[Lymphoid hyperplasia of the intestine in children. 15 cases].

Fifteen cases of nodular lymphoid hyperplasia (NLH) of the bowel in patients aged 17 months to 15 years are reported. Fourteen patients had NLH confined to the small bowel and one had involvement of both the small bowel and colon. Mean age at diagnosis was 10 years. The most common presenting symptoms were intestinal manifestations (86%). Diagnosis was suspected upon roentgenographic studies in one case and digestive endoscopy in ten cases. Histologic confirmation was obtained in all fifteen patients. Immunohistochemical studies, done in 8 patients, demonstrated a paucity of IgA plasmocytes in one patient with an immune deficiency and a polyclonal plasmocyte population with mainly IgA plasmocytes in the seven other patients. Five patients had a deficiency in humoral immunity, with variable expression hypogammaglobulinemia in three patients and IgA deficiency in two; intestinal giardiasis was found in eight patients. Histologic outcome was documented in five cases; evidence of NLH disappeared in only one patient. Metronidazole improved clinical symptoms in most instances.


[Infantile cystinosis. A new Tunisian case].

A case of cystinosis in a three and a half-year-old is reported. Suggestive manifestations included severe rickets, small stature, and complex renal tubule dysfunction meeting the criteria for secondary Fanconi syndrome. Diagnosis was established by the discovery of retinal lesions upon ophtalmologic evaluation and, above all, by the finding that intracellular leukocyte cystine levels were increased to 16 mumol of 1/2 cystine per gram protein. Cystinosis is severe because it inevitably leads to renal failure. Much hope is currently placed in the use of cysteamine to delay this and other complications. At present, early antenatal diagnosis during the first ten weeks of pregnancy is needed in high-risk families to allow elective termination of pregnancy within the legal time limit.


[HbD Iran-beta-thalassemia association in a Tunisian family].

A nine-year-old boy from Béjà (North-Western Tunisia) was found to have both HbD Iran and beta-thalassemia. This patient presented with anemia and slight enlargement of the spleen and had a history of acute episodes of hemolysis. Structural studies on this hemoglobin variant used several miniaturized techniques, mainly carboxy-methyl-cellulose chromatography, reverse-phase high performance liquid chromatography and manual peptide sequencing using Chang's technique. The glutamic acid in position 22 on the beta chain was found to be replaced by a glutamine, establishing the diagnosis of HbD Iran. Concomitant presence of a thalassemia trait was suggested by the finding in the index patient of microcytosis, hypochromia and increased HbA2. The family study confirmed this patient's combined heterozygous anomalies, showing the D trait in the father and the beta thalassemia trait in the mother. The same combination was found in the index patient's sister who was, however, free of clinical symptoms. The explanation of this difference in clinical expression was provided by the ADN study which disclosed deletion of an alpha gene in the girl. The resulting alpha chain deficiency counterbalanced the beta chain deficiency.


[Posterior urethral valves in Senegalese children. Fourteen cases].

Fourteen pediatric cases of posterior urethral valves in patients aged 6 months to 14 years (with four infants and ten older children) are reported. The main symptoms were vesical, including dysuria, acute urinary retention and dribbling. One patient presented with diarrhea, vomiting and dribbling. Urethral valves were looked for as part of the evaluation for urinary lithiasis in one patient, and in another urinary lithiasis developed following the diagnosis of urethral valves. In half the cases, onset of symptoms occurred within one year of birth. Urethrocystography allowed to evidence the valves and to evaluate repercussions on the bladder including hyperplasia (7 cases) and diverticula (2 cases). The intravenous urogram disclosed bilateral ureterohydronephrosis in eight cases. Pathogens recovered from the urine included Klebsiella (3 patients), Pseudomonas (4 patients), Proteus (one patient), and E. coli (one patient). Most patients were treated by catheter lamination under antimicrobial therapy. Two patients died from renal failure. Results were considered satisfactory in nine cases with follow-ups ranging from 1 month to 4 years. Three patients were lost to follow-up. Early diagnosis is essential and management should rely mainly on endoscopic resection which reduces the length of the hospital stay and the risk of infection.


[Incidence of peri- and intraventricular hemorrhages in a premature population at the Central Hospital of Yaounde (Cameroon)].

In Cameroon, prematurity is common but few studies have been carried out on periventricular and intraventricular hemorrhage in premature neonates. Seventy neonates born between 28 and 34 weeks gestational age were studied by cerebral ultrasonography. Thirty infants (42.8%) showed evidence of periventricular or intraventricular bleeding. This proportion was 58.3% in infants born between 28 and 31 weeks gestational age. All stage III (3 cases) and stage IV (2 cases) hemorrhages were bilateral. Bilateral bleeding was less common among patients with stage I (2 cases) or stage II (2 cases) hemorrhages. Among patients born between 32 and 34 weeks gestational age, only 34.8% had ventricular hemorrhage which was always stage I or II and usually unilateral (two stage I and one stage II bilateral bleeds). The incidence of periventricular and intraventricular hemorrhage is high in Yaoundé. Ultrasonographic evaluation should be routinely performed in infants born before 35 weeks gestational age.


[Epidemiologic and clinical aspects of child tuberculosis in Gabon. Retrospective study of 47 cases].

Forty-seven pediatric cases of tuberculosis seen over three years in a department of general pediatrics are reviewed. The main epidemiological and clinical features were studied. Yearly incidence approximated 1.42% in the department. In most instances the source of contamination was not identified. Most patients had not been immunized according to recommendations. Early immunization should be performed and followed by routine tests for vaccine-induced immunity during the first two years.


Membranous bone lengthening: a serial histological study.

Bone lengthening using the process of corticotomy and gradual distraction of callus is applicable to the membranous bone of the canine mandible. In this study the precursors to bone formation, in the area between the distracted bone edges, are analyzed in an attempt to determine the mechanism of bone formation. Ten mongrel dogs 5 months of age were studied. A unilateral, periosteal-preserving angular corticotomy was performed, and an external bone-lengthening device was fixed to the mandible. After 10 days of external fixation, the mandible was lengthened 1 ml per day for 20 days and then held in external fixation for 8 weeks. The dogs were killed for histological and microradiographic study at 10 and 20 days of distraction, and at 14, 28, and 56 days after the completion of distraction. It was observed that the gap between the distracted bone edges is first occupied by fibrous tissue. As distraction proceeds, the fibrous tissue becomes longitudinally oriented in the direction of distraction. Early bone formation advances along the fibrous tissue, starting from the cut bone ends. Eventually the area is converted to mature cortical bone. Bone is formed predominantly by intramembranous ossification. This mechanism is similar to that of bone formation during long bone lengthening.


Improving the acute nasolabial angle and medial nasolabial fold by levator alae muscle resection.

An acute nasolabial angle and a prominent nasolabial fold are two features that are often associated in the aging face. A new technique is presented that simultaneously addresses both of these features. Levator alae (levator labii superioris alaeque nasi) muscle resection, performed through a subciliary incision, improves the acute nasolabial angle without concomitant rhinoplasty. At the same time, levator alae muscle resection softens the medial nasolabial fold. Partial levator labii superioris muscle resection has occasionally been added to further weaken the middle nasolabial fold. Fresh cadaver dissections were performed to define the anatomy and to plan the surgical approach. This report describes a series of 10 patients who underwent this procedure, with improvement of the acute nasolabial angle and softening of the medial nasolabial fold.


Tissue expansion in the extremities using external reservoirs.

Over a 24-month period, 18 patients had 33 expanders placed in the extremities. Twelve expansions were performed in the upper extremity, and 21 in the lower extremity. Indications for expansion include scarring, excision of skin grafts, tumor excision, burn scars, tattoos, or unacceptable incisional scars for revision. Of the 12 expansions performed in the upper extremity in seven patients, nine were successful. Nine expansions in the thigh and two expansions in the region of the knee were completed without complication. Three expansions were performed in the distal lower extremity following crush injury to remove scarring, and all three failed. Seven expansions were performed in the foot for removal of scarred tissue. There was one infection, two skin necroses on the dorsum of the foot, and one implant exposure. Seven complications in the lower extremity occurred in these areas with an infection rate of 20%. The remaining 23 expansions were performed for soft tissue defects in the upper extremity or in the lower extremity above the level of the mid-calf, with only two complications of implant exposure or infection. Therefore, the infection rate and complication rate in the upper extremity and above the knee was only 6%. Overall, 23 of the 33 expansions, or 70%, were taken to completion with a successful advancement of expanded flaps. Overall, complications occurred in 30% of patients, all eventually requiring removal of the expander.(ABSTRACT TRUNCATED AT 250 WORDS)


Heterotopic ossification as a complication of the staged total thigh muscles flap in spinal cord injury patients.

Between 1980 and 1990, 24 total thigh flap procedures were performed at Rancho Los Amigos Medical Center (Downey, CA) by the Pressure Ulcer Management Service. An unexpected occurrence was identified, that is, the rapid development of heterotopic ossification (HO) occurring in the exposed muscle flap between the first and second stages. There were 15 two-stage total thigh flap procedures on 14 patients performed between 1980 and 1990. Of these 15 flap procedures, 11 in 10 patients were found to have HO evident at the second-stage debridement/closure. In comparing our findings with those in other studies (earliest evidence of HO at 19 days), the initial presentation of HO in affected tissues might be even earlier than previously detected. The risks and technical difficulties due to development of HO associated with the two-stage total thigh flap procedure point toward future modifications in preoperative planning that may prove beneficial. Therefore, if the two-stage total thigh flap procedure is necessary, the interval between initial debridement/disarticulation (stage 1) and definitive flap closure (stage 2) should be kept to an absolute minimum. Additionally, HO medicinal prophylaxis (that is, indomethacin or diphosphonates) or radiation after the first stage of the total thigh flap procedure should be considered. Our final conclusion is that the total thigh flap procedure should be done as a one-stage procedure if possible.


The universal nose of early childhood: nature's aid in understanding the supratip deformity and its correction.

The noses of the babies of the world are strikingly similar despite race. Overresected noses have the same characteristics as babies' noses for exactly the same reason: in both cases the nasal skin is relatively unsupported by its underlying skeleton. Teaching rhinoplasty is a most difficult task, but nature offers valuable help in understanding the delicate balance between nasal skeleton and skin sleeve. Nature transforms the "universal nose of early childhood" into an adult nose by gradually augmenting the nasal skeleton, thus showing us the way to correct the iatrogenically overreduced nose.


The influence of diabetes on free flap transfer: I. Flap survival and microvascular healing.

Although recent clinical case presentations suggest that diabetes does not predispose free tissue transfers to increased risk of failure, this remains an open question. The present study used a syngeneic rat strain (Lewis) for free groin flap transplantations between normal rats and streptozotocin-induced diabetic rats (2 months' duration of symptoms), to investigate the influence of diabetes on flap transfer. Flap survival at 1 week, vascular patency, flap histology and ultrastructure, and scanning electron microscopy of anastomotic sites and of corrosion casts of flap vasculature were used as bases for comparison. No differences were found in comparisons of flap survival between any groups of transfer combinations (normal flap onto normal recipient, diabetic flap onto normal recipient, normal flap onto diabetic recipient, and diabetic flap onto diabetic recipient); 100% success was achieved in each group. No differences were found in histology or corrosion casts. Transmission electron microscopy revealed a thickening of the capillary basement membrane in rat diabetic skin after only 8 weeks of symptoms. This ultrastructural finding is consistent with similar capillary basement membrane thickening seen in many other tissues of short- and long-term diabetic animals and humans. Re-endothelialization across the arterial anastomosis at 2 weeks postoperatively was significantly faster in normal versus diabetic animals (p less than 0.05). The predominantly negative findings of this study support the application of free flap transfers in diabetic patients. It is concluded that reconstructive efforts involving free tissue transfer may not be contraindicated in diabetic patients.


The influence of diabetes on free flap transfer: II. The effect of ischemia on flap survival.

Insulin-dependent diabetes mellitus causes microangiopathic changes in many tissues, including skin and muscle. It is not known if such changes are detrimental to free flap transfer, particularly after extended ischemia. To address this issue, we used an experimental design by using a syngeneic rat strain (Lewis) for free groin flap and muscle flap transplantations from streptozotocin-induced diabetic rats (2 month's duration of symptoms) to normal rats. Flaps from age-matched normal donors were transplanted to normal recipients for control comparisons. Groin flaps were stored ischemically for 12 or 18 hours at room temperature, or for 48 hours in the cold (4 degrees C) before transplantation. Flap survival and vascular patency were assessed at 7 days. Cutaneous maximus muscle flaps were transplanted to the groins of recipients after 6 hours of room temperature ischemia. Vascular patency, muscle viability, flap weight change (edema), and dehydrogenase activity were assessed after 2 days of reperfusion. Seventy percent, 67%, and 73% of diabetic groin flaps survived after 12, 18, or 48 (cold) hours of ischemia, respectively, in comparison with 90%, 73%, and 87% of normal flaps undergoing the same respective ischemia periods. The differences were not significant, even when the data were pooled (p greater than 0.1). Muscle flaps also showed no significant differences for the parameters studied. These results support the use of microvascular reconstructive surgery in diabetic patients, suggesting that moderate ischemic challenges do not compromise free flap transfer or extremity replantation.


Clinical application of the adipofascial turnover flap in the leg and ankle.

In soft-tissue defects with bone exposure over the leg and ankle, it is often impossible to achieve wound closure by a simple skin graft. In this article, we present a simple and effective way to reconstruct complicated skin defects on the pretibial region (four patients), the ankle (three patients), the distal fibula (one patient), and the medial aspect of the leg (one patient). Dissection of the local adipofascial turnover flap is quite easy and quick, requires less time, and involves less risk to the patient. It can be completed as a single-stage procedure, and no muscle function or major artery must be expended. Although there are numerous options for reconstruction of soft-tissue defects of the leg and ankle, the nonbulky adipofascial turnover flap appears particularly indicated for small- to medium-sized defects. The contours of the recipient and donor sites are acceptable aesthetically. Adequate flap-to-base area ratio and length-to-width ratio, tension-free insetting of the flap, and noncompression dressing are essential for the flap's survival.


Reconstruction of the distal foot dorsum with a distally based extensor digitorum brevis muscle flap.

We have successfully applied a reverse flow island flap of extensor digitorum brevis muscle for coverage of tissue defects in the distal portion of the foot dorsum in 2 patients. This flap covered the metatarsophalangeal area well with cadaver limb dissection and seems useful to cover the defect in the distal foot dorsum.


Verification of the pressure provocative test in carpal tunnel syndrome.

Three provocative tests (pressure, Phalen's test, and Tinel's sign) were studied in 30 patients with carpal tunnel syndrome and 30 control subjects. The pressure provocative test had a sensitivity of 100%. In contrast, Phalen's test was 88% sensitive and Tinel's sign only 67% sensitive. The pressure provocative test is a sensitive indicator of median nerve compression at the wrist with a faster reaction time than Phalen's test (mean time of 9 seconds vs 30 seconds). It is an appropriate provocative test in patients with stiff or painful wrists when wrist flexion is restricted.


Transinterosseous transfer of a peroneal island flap for reconstruction of prepatellar skin defect: report of two patients.

We describe the use of a peroneal vascular transinterosseous island flap for the resurfacing of a prepatellar skin defect in 2 patients. Being a fasciocutaneous flap, the peroneal flap is thin, and the location of perforators is easily and safely detected with a Doppler flowmeter. When used as a vascular island flap, either a distal pedicle or a proximal pedicle can be used. The peroneal flap can be used as either a free flap or a vascularized fibular and fasciocutaneous flap. It may, therefore, be applied to compound skin, subcutaneous tissue, and bone defects in the lower extremities. A peroneal vascular transinterosseous island flap can reach a prepatellar skin defect, whereas the peroneal island flap with conventional proximal pedicle cannot.


Massive extravasation of traumatically ruptured buttock silicone prosthesis.

Although requests for gluteal implants are unusual in the United States, the use of silicone implants for buttock cosmesis has been described. Complications of this procedure have rarely been reported. There are no reports of long-term follow-up in these patients. This report describes the traumatic rupture of a silicone buttock implant nine years after initial surgical placement. Massive silicone extravasation and migration, along with silicone granuloma formation, occurred. The contralateral implant remained intact, functional, and cosmetically acceptable. The surgical approach and repair of this injury is outlined and discussed. We conclude that early surgical treatment of extravasation injuries is needed and that buttock reconstruction with implants can be useful, but close follow-up is needed. We also suggest there is a need to evaluate alternative materials for use in this procedure.


Congenital alveolar adhesions.

We report an infant girl with congenital alveolar adhesions and a cleft palate. The mucosal bands were resected the day after birth. Stretching exercises of the mandible improved the range of movement at the temporomandibular joint. Two weeks of therapy were required before full mouth opening was possible. Previously reported patients and theories of embryogenesis are reviewed.


Differentiation requires continuous active control.

The problems posed by differentiation that appear most soluble by a passive control mechanism can readily be solved by an active mechanism. Given the need for plasticity in gene expression in different cell types at different stages, an active mechanism may be advantageous, even essential. It is striking how few changes during differentiation are completely irreversible, the gene rearrangements leading to immunoglobulin expression being one clear exception. Indeed, a prediction of the active-control hypothesis is that any nucleus exposed to the appropriate constellation of proteins at the appropriate concentration should be able to perform functions typical of any given differentiated cell type. In the next decade, the elucidation of novel memory mechanisms, or feedback loops, will substantially increase our understanding of how stable differentiated states can be maintained by continuous active control.


DNA looping.

DNA looping is widely used in nature. It is well documented in the regulation of prokaryotic and eukaryotic gene expression, DNA replication, and site-specific DNA recombination. Undoubtedly looping also functions in other protein-DNA transactions such as repair and chromosome segregation. While the underlying physical chemistry of DNA looping is common to all systems, the precise biochemical details of looping and the utilization of looping by different systems varies widely. Looping appears to have been chosen by nature in such a wide variety of contexts because it solves problems both of binding and of geometry. The cooperativity inherent in binding a protein to multiple sites on DNA facilitates high occupancy of DNA sites by low concentrations of proteins. DNA looping permits a sizeable number of DNA-binding proteins to interact with one of their number, for example RNA polymerase. Finally, DNA looping may simplify evolution by not requiring a precise spacing between a protein's binding site and a second site on the DNA.


Zinc proteins: enzymes, storage proteins, transcription factors, and replication proteins.

In the past five years there has been a great expansion in our knowledge of the role of zinc in the structure and function of proteins. Not only is zinc required for essential catalytic functions in enzymes (more than 300 are known at present), but also it stabilizes and even induces the folding of protein subdomains. The latter functions have been most dramatically illustrated by the discovery of the essential role of zinc in the folding of the DNA-binding domains of eukaryotic transcription factors, including the zinc finger transcription factors, the large family of hormone receptor proteins, and the zinc cluster transcription factors from yeasts. Similar functions are highly probable for the zinc found in the RNA polymerases and the zinc-containing accessory proteins involved in nucleic acid replication. The rapid increase in the number and nature of the proteins in which zinc functions is not unexpected since zinc is the second most abundant trace metal found in eukaryotic organisms, second only to iron. If one subtracts the amount of iron found in hemoglobin, zinc becomes the most abundant trace metal found in the human body.


The value of electrophoretic fingerprinting and karyotyping in wine yeast breeding programmes.

Electrophoretic banding patterns of total soluble cell proteins, DNA restriction fragments and chromosomal DNA were used to characterise ten strains of Saccharomyces cerevisiae used for commercial production of wine. These fingerprinting procedures provided unique profiles for all the different yeast strains and can therefore be used to identify and control industrial strains. Furthermore, the protein profiles, restriction fragments banding patterns and electrophoretic karyotyping by contour clamped homogeneous electric field electrophoresis (CHEF), were valuable to differentiate hybrid and parental strains in yeast breeding programmes. Hybrid strains, with desirable oenological properties, were obtained by mass spore-cell mating between a heterothallic killer yeast and two homothallic sensitive strains and all were shown to have unique DNA fingerprints and electrophoretic karyotypes.


Arginine and proline genes of Aspergillus niger.

Aspergillus niger mutants defective in arginine or proline biosynthesis have been isolated and 12 genetic loci were identified. Mutation was induced by low doses UV, and mutants were isolated after filtration enrichment. The mutants were classified according to their phenotype in growth tests and were further characterized in complementation tests. The arginine auxotrophic mutants represent nine complementation groups. Three additional complementation groups were found for mutants that could grow on proline (two of them on arginine too). Linkage group analysis was done in somatic diploids obtained from a mutant and a master strain with genetic markers on six chromosomes. The arg genes belong to six different linkage groups and the pro genes to two. One arg-mutant could be complemented by transformation with the A. nidulans argB+ gene, and this A. niger gene thus appeared to be homologous to the A. nidulans argB. We isolated an A. niger strain with the argB gene tightly linked with the nicA1 marker. This strain is very suitable as acceptor for transformation with an argB-plasmid, because transformants with inserts on the homologous site can be recognized and analyzed genetically using the nicA1 marker gene.


The occurrence of disporous Bacillus thuringiensis cells.

Ultrathin sections of sporulating Bacillus thuringiensis were examined in a transmission electron microscope. Less than 1% of the about 2,000 approximately sagittal sections of the bacterial cells examined contained two endospores per cell. This finding clarifies the majority of textbook and research reports (which tend to be ambiguous), contradicts several of the most recent textbook reports, and confirms three unillustrated textbook reports, in relation to the occurrence of disporous bacilli. Electron microscopic evidence of the observation is presented, apparently for the first time.


Botryozyma nematodophila gen. nov., spec. nov. (Candidaceae).

The new genus Botryozyma with a single species, B. nematodophila is proposed for two isolates from nematodes (Panagrellus zymosiphilus) occurring in grapes with sour-rot. The new genus has typical ascomycetous characteristics and, being unable to produce ascospores, is placed in the family Candidaceae.


Neotypification of the genus Trichosporon.

The currently accepted type species of the genus Trichosporon Behrend is T. beigelii. This species has formerly been regarded as identical to T. cutaneum. However, these fungi are now known to represent separate species with different ecology. The first species described in Trichosporon was T. ovoides, an agent of human white piedra. A neotype strain is designated for this species, while a lectotype strain is indicated for T. cutaneum. The name T. beigelii is considered as doubtful and consequently cannot be maintained.


Contributions to a revision of the genus Trichosporon.

The genus Trichosporon was revised using characters of morphology, ultrastructure, physiology, ubiquinone systems, mol% G + C of DNA, DNA/DNA reassociations and 26S ribosomal RNA partial sequences. A total of 101 strains was used, including all available type and authentic cultures of previously described taxa. Nineteen taxa could be distinguished, 15 of which having Q-9 coenzyme systems and 4 having Q-10. Sixteen previously described names were reduced to synonymy. One new species was described. The genus is characterized by the presence of arthroconidia. Few species possess further diagnostic morphological characters, such as the presence of appressoria, macroconidia or meristematic conidiation. The septa of two species were found to be non-perforate, while those of the remaining species contained dolipores at variable degrees of differentiation, with or without vesicular or tubular parenthesomes. All species were able to assimilate a large number of carbon compounds; visible CO2 production was absent. The genus was found to be fairly homogeneous on the basis of a phylogenetic analysis of partial 26S rRNA sequences, with the exception of T. pullulans which proved to be unrelated. Most taxa were found to occupy well-defined ecological niches. Within the group of taxa isolated from humans, a distinction could be made between those involved in systemic mycoses and those which mainly caused pubic or non-pubic white piedras, respectively. One species was consistently associated with animals, while others came mainly from soil or water. One species was mesophilic and another psychrophilic.


The flocculation of wine yeasts: biochemical and morphological characteristics in Zygosaccharomyces--flocculation in Zygosaccharomyces.

The floc-forming ability of flocculent strains of Zygosaccharomyces bailii and Z. fermentati, isolated from musts, was tested for susceptibility to proteinase and sugar treatments. Z. fermentati was found highly resistant to the proteolytic enzymes tested, whereas Z. baili was only trypsin-resistant. The inhibition of flocculation by sugars distinguished two types: in Z. fermentati flocculation was completely inhibited by mannose, in Z. bailli by various sugars. By SEM observation, the cell surface of Zygosaccharomyces revealed the presence of a column structure, resulting from fusion of vesicles present on the cell surface.


Detection of Aspergillus and Penicillium extracellular polysaccharides (EPS) by ELISA: using antibodies raised against acid hydrolysed EPS.

Species of the fungal genera Aspergillus and Penicillium produce immunologically active extracellular polysaccharides (EPS) in which galactofuranose residues are immunodominant. The antigenic determinant of the EPS of A. fumigatus, A. niger and P. digitatum could be removed by acid hydrolysis. Due to the hydrolysis of the EPS the immunological reaction between IgG anti-native EPS and hydrolysed EPS disappeared. Antibodies raised in rabbits against the acid hydrolysed EPS revealed new antigenic determinants that were exposed as a result of the acid hydrolysis. Immunological inhibitory experiments showed that the antibodies were no longer directed to galactofuranose residues. Enzyme Linked Immunosorbent Assay, carried out with antibodies raised against the acid hydrolysed EPS showed that the antibodies against the acid hydrolysed EPS were more species specific in comparison with the antibodies against the native EPS.


Plasmid-determined resistance to arsenic and antimony in Pseudomonas aeruginosa.

Resistance to arsenic salts in a Pseudomonas aeruginosa clinical isolate was shown to be determined by a 100 kb transferable plasmid. The resistance pattern included arsenate, arsenite, and antimonate ions. Arsenate and arsenite resistances were inducible by previous exposure of cultures to subinhibitory amounts of either of the two ions. Phosphate ions protected P. aeruginosa cells from the toxic effects of arsenate but did not alter arsenite toxicity.


The role of an endogenous nonheme iron in microsomal redox reactions.

Microsomal membranes contain a nonheme iron which serves in vitro for the peroxidation of unsaturated lipids or the oxidation of several other chemicals. These redox reactions are reviewed in light of a recent identification of two or more iron-binding proteins in the microsomal milieu. Indirect evidence that the microsomal iron might serve in vivo for the synthesis of heme iron is also presented and discussed. Consistent with this, the newly identified iron proteins not only participate in redox reactions but also release their bound iron upon incubation with certain intermediates of heme synthesis.


Allosteric regulation of tPA-mediated plasminogen activation by a modifier mechanism: evidence for a binding site for plasminogen on the tPA A-chain.

We studied the mechanism responsible for nonlinear double reciprocal plots for tissue type plasminogen activator (tPA)-mediated plasminogen activation reported previously by several groups. We found nonlinear Eadie-Scatchard plots for Glu-plasminogen activation by recombinant single-chain tPA confirming a non-Michaelis-Menten behavior of tPA. In order to characterize this mechanism, enzyme kinetic studies with truncated substrates (Lys- and miniplasminogen) and modified or truncated enzymes (two-chain tPA and tPA B-chain) were performed. Thereby it could be excluded that product-mediated modifications of the enzyme or the substrate are responsible for the nonlinear plots. Linear plots, i.e., Michaelis-Menten kinetics, were only found when tPA B-chain was used as a plasminogen activator, indicating that the tPA A-chain should be responsible for the non-Michaelis-Menten behavior. Binding studies of plasminogen to immobilized tPA A-chain in fact demonstrated a saturable binding of Glu- and miniplasminogen to the A-chain of tPA with a KD approximately 0.1 microM and one binding site per molecule of tPA A-chain. These data suggested a modifier mechanism responsible for the nonlinear plots whereby the substrate plasminogen itself could function as a modifier. When such a mechanism was included into a model for tPA-mediated plasminogen activation, the experimentally obtained data could be fitted into such a model by nonlinear regression analysis with resulting p-values of less than 0.001.


Purification and characterization of glucosamine-6-phosphate deaminase from dog kidney cortex.

Glucosamine-6-phosphate deaminase (EC 5.3.1.10) from dog kidney cortex was purified to homogeneity, as judged by several criteria of purity. The purification procedure was based on two biospecific affinity chromatography steps, one of them using N-epsilon-amino-n-hexanoyl-D-glucosamine-6-phosphate agarose, an immobilized analog of the allosteric ligand, and the other by binding the enzyme to phosphocellulose followed by substrate elution, which behaved as an active-site affinity chromatography. The enzyme is an hexameric protein of about 180 kDa composed of subunits of 30.4 kDa; its isoelectric point was 5.7. The sedimentation coefficient was 8.3S, and its frictional ratio was 1.28, indicating that dog deaminase is a globular protein. The enzyme displays positive homotropic cooperativity toward D-glucosamine-6-phosphate (Hill coefficient = 2.1, pH 8.8). Cooperativity was completely abolished by saturating concentrations of GlcNAc6P; this allosteric modulator activated the reaction with a typical K-effect. Under hyperbolic kinetics, a Km value of 0.25 +/- 0.02 mM for D-glucosamine-6-phosphate was obtained. Assuming six catalytic sites per molecule, kcat is 42 s-1. Substrate-velocity data were fitted to the Monod's allosteric model for the exclusive-binding case for both substrate and activator, with two interacting substrate sites. The Kdis for N-acetyl-D-glucosamine-6-phosphate was estimated at 14 microM.


Proteolysis with trypsin of mammalian tyrosinase isoforms from B16 mouse melanoma.

In spite of the central role of tyrosinase in mammalian pigmentation, few data are available on its structure and structure-function relationships based on direct analysis of the protein. A number of reasons have been invoked to account for this situation, including the problems for its purification and its resistance to proteases. However, no study on the effects of proteases on purified tyrosinase has been reported. We have purified the melanosomal and cytosolic tyrosinases from B16 mouse melanoma and analyzed their susceptibility to trypsin digestion. Both isoforms are sensitive to trypsin, and display similar peptide maps and kinetics of proteolysis, suggesting that they are products of the same gene. The peptide maps and the kinetics of appearance of the fragments were consistent with the sequential removal of N-terminal peptides, leading to a core of 55.3 kDa for the melanosomal form and 48.6 kDa for the cytosolic enzyme. This core was apparently resistant to further proteolysis and catalytically inactive. The difference in molecular weight for the core of the cytosolic and melanosomal forms is the same as that calculated for the native isoforms. The kinetics of enzyme inactivation indicate that the tyrosine hydroxylase and Dopa oxidase activities of tyrosinase are lost at the same rate, and should therefore display similar if not identical structural requirements. The results are discussed in terms of the relationship of both isoforms and of the putative protein sequences deduced from the cDNA clones proposed for tyrosinase.


Degradation of rat liver cytochromes P450 3A after their inactivation by 3,5-dicarbethoxy-2,6-dimethyl-4-ethyl-1,4-dihydropyridine: characterization of the proteolytic system.

The suicide substrate 3,5-dicarbethoxy-2,6-dimethyl-4-ethyl-1,4- dihydropyridine (DDEP) inactivates rat liver cytochrome P450 (P450) 3A isozymes through prosthetic heme alkylation of the apoprotein in a mechanism-based fashion, which marks them for rapid proteolysis. In this article, through the use of epitope-specific monoclonal antibodies, we show that both 3A1 and 3A2 isozymes are targeted for proteolysis. Furthermore, using intact rats, isolated rat hepatocytes, and rat liver subcellular fractions supplemented with ATP and MgCl2, as well as various proteolytic inhibitors as probes, we now report that the hepatic cytosolic ubiquitin-dependent proteolytic system rather than hepatic lysosomes is involved in the rapid degradation of DDEP-induced heme alkylated P450s 3A.


Location and characterization of multiple glucocorticoid-responsive elements in the rat serine dehydratase gene.

Transcription of the gene coding for serine dehydratase (SDH, EC 4.2.1.13) in the rat in vivo is dramatically increased by glucocorticoid hormones. To identify DNA elements mediating the glucocorticoid-regulated expression of the SDH gene, we transiently transfected 7AD-7 rat hepatoma cells with fusion genes consisting of various regions of the SDH 5' flanking sequence linked to the coding sequence of the gene for chloramphenicol acetyltransferase (CAT). Analysis of the CAT activities from these 5' deletion mutants identified three closely associated glucocorticoid-responsive elements (GREs), located more than 5 kb upstream relative to the cap site. Two distal GREs act synergistically to confer strong glucocorticoid inducibility to the gene, whereas the proximal GRE functions independently of the distal GREs and confers only a weak hormone response to the gene. The purified DNA-binding domain of rat glucocorticoid receptor binds to the sequence of each GRE as shown by footprinting experiments. However, only one of these sequences contains the TGTTCT consensus sequence reportedly associated with many other GREs.


Polyvanadate-stimulated NADH oxidation by plasma membranes--the need for a mixture of deca and meta forms of vanadate.

Polyvanadate solutions obtained by extracting vanadium pentoxide with dilute alkali over a period of several hours contained increasing amounts of decavanadate as characterized by NMR and ir spectra. Those solutions having a metavanadate:decavanadate ratio in the range of 1-5 showed maximum stimulation of NADH oxidation by rat liver plasma membranes. Reduction of decavanadate, but not metavanadate, was obtained only in the presence of the plasma membrane enzyme system. High simulation of activity of NADH oxidation was obtained with a mixture of the two forms of vanadate and this further increased on lowering the pH. Addition of increasing concentrations of decavanadate to metavanadate and vice versa increased the stimulatory activity, reaching a maximum when the metavanadate:decavanadate ratio was in the range of 1-5. Increased stimulatory activity can also be obtained by reaching these ratios by conversion of decavanadate to metavanadate by alkaline phosphate degradation, and of metavanadate to decavanadate by acidification. These studies show for the first time that both deca and meta forms of vanadate present in polyvanadate solutions are needed for maximum activity of NADH oxidation.


Fungal quinone pigments as oxidizers and inhibitors of mitochondrial NADH:ubiquinone reductase.

The interaction of fungal quinone pigments bostricoidin, fusarubin, javanicin, and 2-oxyjuglone with mitochondrial NADH:ubiquinone reductase (complex I, EC 1.6.99.3) has been studied. The bimolecular rate constants (turnover number (TN)/Km) of rotenone-insensitive reduction of these compounds are in the range of 1.2 x 10(4)-1.6 x 10(5) M-1s-1. 2-Oxyjuglone acts as inhibitor of NADH:ferricyanide reductase reaction of complex I (KI = 30 microM). All quinone pigments, except javanicin, decrease the TN of reduction of 5,8-dioxy-1,4-naphtoquinone being reduced at its binding site but with significantly lower TN. They do not affect the rotenone-sensitive reduction of ubiquinone-1. The binding of quinone pigments close to the NADH and ferricyanide binding site is suggested. It seems that quinone pigments, especially 2-oxyjuglone, react with complex I faster than it follows from their approximate values of one-electron reduction potential calculated from their reactivities with flavocychrome b2 and adrenodoxin.


Effect of hydrogen peroxide on calcium homeostasis in smooth muscle cells.

One of the major biological targets of free radical oxidations, prone, for anatomical reasons, to oxidative challenges, is the cardiovascular system. In the present paper the effect of hydrogen peroxide on intracellular ionized calcium ([Ca2+]i) homeostasis in smooth muscle cells (SMC) is studied, the major aim of the study being a better understanding of the protective effect of antioxidants and Ca2+ channel blockers. The exposure of SMC to 300 microM H2O2 induced a rapid increase of [Ca2+]i, followed by a decrease to a new constant level, higher than the basal before the oxidative challenge. When incubation medium was Ca2+ free, the pattern of [Ca2+]i change was different. The rapid increase was still observed, but it was followed by a rapid decrease to a level only slightly above the basal before the oxidative challenge. The involvement of intracellular Ca2+ stores was tested by using vasopressin, a hormone able to induce discharge of inositol 1,4,5-triphosphate-sensitive Ca2+ stores. When H2O2 was added after vasopressin no [Ca2+]i increase was observed. Treatment of cells, in which the stable increase of [Ca2+]i was induced by H2O2, with disulfide reducing compounds, induced a progressive decrease of [Ca2+]i toward the level observed before the oxidative challenge. Calcium channel blockers and antioxidants, on the other hand, effectively prevented the stabilization of [Ca2+]i at the high steady-state, after the internal Ca2+ release phase. Dihydropyridine Ca2+ channel blockers were by far more active than verapamil and among those the most active was lacidipine. Also the antioxidants trolox and N,N'-diphenyl-1,4-phenylenediamine both prevented the [Ca2+]i unbalance. These results suggest that Ca+ channel blockers and antioxidants, although inactive on oxidative stress-induced Ca2+ release from intracellular stores, prevent the increased influx apparently related to a membrane thiol oxidation.


Localization of two binding domains for thrombospondin within fibronectin.

Thrombospondin is a major glycoprotein of the platelet alpha-granule and is secreted during platelet activation. Several protease-resistant domains of thrombospondin mediate its interactions with components of the extracellular matrix including fibronectin, collagen, heparin, laminin, and fibrinogen. Thrombospondin, as well as fibronectin, is composed of several discretely located biologically active domains. We have characterized the thrombospondin binding domains of plasma fibronectin and determined the binding affinities of the purified domains; fibronectin has at least two binding sites for thrombospondin. Thrombospondin bound specifically to the 29-kDa amino-terminal heparin binding domain of fibronectin as well as to the 31-kDa non-heparin binding domain located within the larger 40-kDa carboxy-terminal fibronectin domain generated by chymotrypsin proteolysis. Platelet thrombospondin interacted with plasma fibronectin in a specific and saturable manner in blot binding as well as solid-phase binding assays. These interactions were independent of divalent cations. Thrombospondin bound to the 29-kDa fibronectin heparin binding domain with a Kd of 1.35 x 10(-9) M. The Kd for the 31-kDa domain of fibronectin was 2.28 x 10(-8) M. The 40-kDa carboxy-terminal fragment bound with a Kd of 1.65 x 10(-8) M. Heparin, which binds to both proteins, inhibited thrombospondin binding to the amino-terminal domain of fibronectin by more than 70%. The heparin effect was less pronounced with the non-heparin binding carboxy-terminal domain of fibronectin. By contrast, the binding affinity of the thrombospondin 150-kDa domain, which itself lacked heparin binding, was not affected by the presence of heparin. Based on these data, we conclude that thrombospondin binds with different affinities to two distinct domains in the fibronectin molecule.


Primary structure of locust flight muscle fatty acid binding protein.

The amino acid sequence of the fatty acid binding protein (FABP) from flight muscle of the locust, Schistocerca gregaria, has been determined. The sequence of the N-terminal 39 amino acid residues, determined by automated Edman degradation, was used to prepare a degenerate oligonucleotide that corresponded to amino acid residues 16-23. cDNA coding for FABP was constructed from flight muscle mRNA and amplified by the polymerase chain reaction using the degenerate oligonucleotide and an oligo dT-NotI primer adapter as primers. The amplification product was cloned and sequenced. Additionally, a cDNA library of flight muscle mRNA was prepared and screened with a 414-bp probe prepared from the clone. The primary structure of locust FABP was compared with the proteins in the Swiss protein databank and found to have significant homology with mammalian FABPs over the entire 133-residue sequence. The best match was versus human heart FABP (41% identity), attesting to the highly conserved nature of this protein. The results suggest that locust muscle FABP is a member of the lipid binding protein superfamily and may provide valuable insight into the evolution of this abundant protein class.


Astaxanthin and canthaxanthin are potent antioxidants in a membrane model.

When the conjugated keto-carotenoids, either astaxanthin or canthaxanthin, are added to rat liver microsomes undergoing radical-initiated lipid peroxidation under air, they are as effective as alpha-tocopherol in inhibiting this process. This contrasts with the effect of beta-carotene, which is a much less potent antioxidant when added in this system, without the addition of other antioxidants.


Association of a heat-stable inhibitor protein with cyclic-3',5'-AMP-dependent protein kinase from the nematode Ascaris suum: purification and characterization of the inhibitor.

An inhibitor protein of the catalytic subunit of the cyclic 3',5'-AMP-dependent protein kinase from the nematode Ascaris suum was isolated and characterized. The molecular weight of the inhibitor was estimated as 28,000 by electrophoresis under denaturing conditions and as 30,000 by gel permeation chromatography on Superose 12. The Trypsin-labile inhibitor was resistant to short incubations (less than or equal to 5 min) at temperatures up to 95 degrees C and at pH 3. It affected the protein kinase from Ascaris and bovine heart with almost the same affinity, and inhibition was not relieved by the presence of cAMP and cGMP. However, the inhibition was antagonized by low concentrations of heparin. Unlike in mammalian tissues, the concentration of the inhibitor was sufficiently high to exert at least 90% inhibition of the protein kinase activity in Ascaris muscle. Therefore, the inhibitor may play a role in cellular regulation in the nematode.


Studies on geranylgeranyl diphosphate synthase from rat liver: specific inhibition by 3-azageranylgeranyl diphosphate.

Geranylgeranyl diphosphate synthase from rat liver was separated from farnesyl diphosphate synthase, the most abundant and widely occurring prenyltransferase, by DEAE-Toyopearl column chromatography. The enzyme catalyzed the formation of E,E,E-geranylgeranyl diphosphate (V) from isopentenyl diphosphate (II) and dimethylallyl diphosphate (I), geranyl diphosphate (III), or farnesyl diphosphate (IV) with relative velocities of 0.09:0.15:1. 3-Azageranylgeranyl diphosphate (VII), designed as a transition-state analog for the geranylgeranyl diphosphate synthase reaction, was synthesized and found to act as a specific inhibitor for this synthase, but not for farnesyl diphosphate synthase. Diphosphate V and its Z,E,E-isomer (VI) also inhibited geranylgeranyl diphosphate synthase, but the effect was not as striking as that of the aza analog VII. Specific inhibition of geranylgeranyl diphosphate synthase by VII was also observed in experiments with 100,000g supernatants of rat brain and liver homogenates which contained isopentenyl diphosphate isomerase and prenyltransferases including farnesyl diphosphate synthase as well as geranylgeranyl diphosphate synthase. For farnesyl:protein transferase from rat brain, however, the aza compound did not show a stronger inhibitory effect than E,E,E-geranylgeranyl diphosphate.


Thyroid peroxidase glycosylation: the location and nature of the N-linked oligosaccharide units in porcine thyroid peroxidase.

Highly purified, trypsin/detergent-solubilized thyroid peroxidase (TPO), prepared from pig thyroid tissue, was subjected to reduction and alkylation followed by trypsin digestion. The resulting peptides were fractionated using HPLC. Corresponding carbohydrate positive regions from three separate HPLC experiments were pooled and further chromatography was carried out to yield purified peptide suitable for sequence analysis and complete carbohydrate composition analysis. Four of the five putative sites for N-linked glycosylation were found to carry oligosaccharide units in which mannose and glucosamine were the sole or predominant sugars. Three of the four glycosylations occur at asparagine residues which are likely to be at beta turns or bends. The fifth putative glycosylation site could not be confirmed and may either be poorly glycosylated or escape glycosylation. All of the confirmed glycosylated sites occur in the N-terminal third of the TPO polypeptide chain, in the portion of the molecule believed to be extracellular. The isolation of at least two chromatographic forms of glycopeptide derived from each of the confirmed sites suggests microheterogeneity in the structure of the oligosaccharide units of thyroid peroxidase similar to that observed in many other glycoproteins.


Regulation of phospholipase C delta activity by sphingomyelin and sphingosine.

Phospholipase C delta (PLC delta) is strongly inhibited by sphingomyelin (SM). The inhibition occurs in both the presence and the absence of spermine, an activator of PLC delta. Phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylinositol (PI) also inhibit PLC delta in the presence of spermine but are much less effective than SM. PE and PC activate and PS and PI inhibit PLC delta in the absence of spermine. Again, the inhibition by PS and PI is much weaker than the inhibition observed with SM. Similar or identical effects are observed in detergent micelle and liposome assays. Comparisons of physiological concentrations of SM with concentrations yielding 50% inhibition of PLC delta in vitro indicate that SM is likely to be a major factor in regulating the activity of PLC delta by inhibition. It is proposed that, in vivo, sphingomyelin acts as an inhibitor of PLC delta, which enables the enzyme to be regulated by activation. In certain circumstances, there is a substantial decline in SM and this may lead to a partial relief of the inhibition. PLC delta is activated by sphingosine in the absence of spermine. However, this activation occurs at unphysiologically high concentrations of sphingosine. The effects of SM and sphingosine on PLC delta in marked contrast to those observed with protein kinase C, which is unaffected by sphingomyelin and inhibited by sphingosine.


Fragmentation of dimyristoylphosphatidylcholine vesicles by apomyoglobin.

Previously we have reported results of a preliminary study on the micellization of phosphatidylcholine vesicles by apomyoglobin at pH 4 (J. W. Lee and H. Kim, 1988, FEBS Lett. 241, 181-184). The micellization study has been extended here to investigate the effect of the lipid to protein ratio, temperature, size of vesicles, and pH. The pH-dependent study indicated that micellization occurs when the protein assumes either a molten globular or random coil structure. Time-dependent hydrophobic labeling by 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)-diazirine showed that there is an initial increase in contact between the protein and hydrophobic acyl chain of lipid followed by a decrease in the interaction. This may be explained as the initial stage of vesicle aggregation which is subsequently superseded by the fragmentation. These reactions are discussed in term of protein unfolding at low pH.


The chelation of nonheme iron within sickle erythrocytes by the hydroxypyridinone chelator CP094.

Nonheme, nonferritin iron has been detected in membrane preparations from sickle erythrocytes and has been suggested to catalyze free radical reactions in these cells contributing to the development of membrane oxidation. In this study the hydroxypyridinone iron chelator, CP094, currently being evaluated as a potentially therapeutic chelator, and desferrioxamine have been studied for their abilities to chelate the nonheme iron within intact sickle erythrocytes under physiological conditions. The results suggest that CP094 can enter sickle erythrocytes, chelate nonheme iron and suppress membrane lipid peroxidation within a timescale in which desferrioxamine does not enter the cells. Suppression of lipid peroxidation showed no protective effect in an in vitro system inducing the formation of irreversibly sickled cells.


Novel protein inhibits in vitro precipitation of calcium carbonate.

Organic molecules both coexist and interact with inorganic crystal lattices in biomineralizing tissues. Mineral precipitation and crystal morphology are tightly regulated by the actions of these molecules. Polyacrylamide gel electrophoresis studies on water soluble extracts from the cuticle of Callinectes sapidus (Atlantic blue crab) reveal the presence, in unmineralized nascent premolt cuticle, of proteins which are absent in the mineralized postmolt cuticle. In the present studies, homogenates from both premolt and postmolt C. sapidus cuticles have been tested for their effect on the in vitro precipitation of calcium carbonate. The role of protein in this process was determined by heat pretreatment and trypsin pretreatment of the cuticle homogenates prior to the precipitation assay. The results from these experiments indicate that proteins, with molecular weights of approximately 75,000 and between 10,000 and 20,000, concentrated in the C. sapidus premolt cuticle, inhibit calcium carbonate precipitation in vitro. The inhibitory activity of these proteins appears to be a result of specific interactions since trypsin, myoglobin, and ovalbumin are not inhibitory. The presence of lower amounts of these inhibitory proteins in C. sapidus postmolt cuticle may be responsible for the subsequent mineralization of this tissue.


Cutaneous reactions to granulocyte-monocyte colony-stimulating factor.

Granulocyte-monocyte colony-stimulating factor (GMCSF) is a hematopoietic growth factor that stimulates the proliferation and differentiation of neutrophils, eosinophils, and monocytes. We reviewed the cutaneous reactions that developed in 26 patients who received GMCSF as part of a chemotherapeutic protocol. Fourteen patients developed immediate localized angioedematous reactions at the subcutaneous GMCSF injection site, and 21 developed generalized cutaneous reactions. Four biopsy specimens were obtained from three patients who had generalized erythrodermic reactions. All specimens showed perivascular and periadnexal lymphocytic inflammation in the dermis, and two showed perivascular and periadnexal eosinophilia. Staining for eosinophil granule major basic protein showed infiltration by eosinophils and extracellular deposition of major basic protein in three specimens from two patients with eosinophilia. Extracellular deposition of neutrophil elastase and mast cell tryptase was minimal. Cutaneous reactions are prominently associated with GMCSF administration. Eosinophils, known to release toxic products after being activated, may have a role in these skin reactions through stimulation by GMCSF.


Treatment of pyoderma gangrenosum with cyclosporine.

Pyoderma gangrenosum is a chronic inflammatory ulcerative skin disease of unknown origin, often associated with various diseases including inflammatory bowel disease, inflammatory arthritis, monoclonal gammopathies, hepatitis, and myeloproliferative disorders. Treatment of associated systemic disorders may improve the ulcers, but lesions may be recalcitrant and persist for months to years. Therapy for pyoderma gangrenosum includes high-dose systemic corticosteroids, sulfa drugs such as sulfasalazine, clofazimine, and immunosuppressive agents such as mercaptopurine and azathioprine; these drugs are sometimes ineffective. We present a series of 11 patients with pyoderma gangrenosum, with a wide range of underlying diseases, whose ulcers were refractory to usual therapy and who were treated with low-dose cyclosporine. Ten of the 11 patients cleared rapidly and completely with cyclosporine therapy. Cyclosporine should be seriously considered as a primary form of treatment for pyoderma gangrenosum.


Exogenous origin of n-alkanes in pathologic scale.

Although n-alkanes accumulate in some disorders of cornification, recent studies using radioactive carbon 14 content by accelerator mass spectrometry point to an exogenous origin for alkanes in normal stratum corneum, and their derivation in congenital ichthyosiform erythroderma remains controversial. Using 14C content to measure sample age, the n-alkane fractions from two patients with congenital ichthyosiform erythroderma contained no detectable contemporary materials. By electron microscopy, alkane-enriched emollients (petrolatum [Vaseline]) permeated to all levels of stratum corneum of hairless mice, expanding the intercellular domains and distorting membrane bilayers. Similar ultrastructural changes were also observed in the stratum corneum of patients with congenital ichthyosiform erythroderma. When alkanes were excluded, no differences in lipid content were evident between two forms of autosomal recessive ichthyosis. These data demonstrate that scale n-alkanes in disorders of cornification derive from environmental sources and indicate the pervasiveness of petroleum-based emollients in skin. Therefore, epidermal lipid analyses must be interpreted with caution. However, these studies do not rule out an important therapeutic and/or pathogenic role for exogenous n-alkanes in skin.


Alopecia areata. Autoreactive T cells are variably enriched in scalp lesions relative to peripheral blood.

Alopecia areata is a condition characterized by hair loss in association with perifollicular infiltration of T cells and antigen-presenting cells. Autoreactive T cells are postulated to amplify this abnormality by interacting with DR+ follicular epithelium. These cells may recognize either autologous major histocompatibility complex class II antigen or an autoantigen restricted by major histocompatibility complex class II. Limiting dilution analysis was used to determine the frequency of autoreactive lymphocytes in scalp biopsy specimens and peripheral blood from seven adult patients with alopecia areata. Autoreactive T cells are defined for this study as those that proliferate in response to autologous irradiated peripheral blood mononuclear cells. Autoreactive lymphocytes were enriched in scalp biopsy specimens relative to peripheral blood in five of seven patients. This enrichment was statistically significant in four of five patients. Five autoreactive T-cell clones derived from lesional scalp were characterized. Four of these clones were CD3+CD4+CD8- and one clone was CD3+CD4-CD8+. Enrichment of autoreactive cells in lesions of alopecia areata supports a role for these cells in the pathogenesis of this condition. Enrichment of autoreactive lymphocytes is also found in allergic contact dermatitis. Thus, these autoreactive lymphocytes may have a general role in inflammation.


Focal dermal hypoplasia syndrome in a male patient. Report of a case and histologic and immunohistochemical studies.

Focal dermal hypoplasia (FDH) is a rare ectomesodermal dysplasia syndrome characterized by cutaneous, skeletal, dental, ocular, and soft-tissue defects. An X-linked dominance with death of male subjects has been assumed as the mode of inheritance. Only a few cases of FDH have been reported in male subjects. A 68-year-old man had typical skin lesions of FDH. Clinical, histologic, and immunohistochemical features are presented. The cutaneous abnormalities consisted of atrophic hyperpigmented and hypopigmented macules and erythematous, slightly raised lesions showing a highly characteristic linear distribution. Other abnormalities, including syndactyly, apocrine hidrocystoma of eyelids, and bilateral cholesteatoma were observed. Only one case of FDH in association with an apocrine hidrocystoma has been reported previously. Consistent findings microscopically in the erythematous lesions were areas of scar formation with subepidermal bulla overlying the neodermis. A strongly positive immunohistochemical reaction for vimentin, fibronectin, and collagen type III was observed in the scar tissue. No collagen type IV was detected in the basement membrane zone of the epidermis covering the lesion. It has been proposed that fibroblastic abnormalities may lead to an alteration of collagen synthesis in FDH, although confirmation of this hypothesis was unavailable. Our findings suggest that production of collagen type IV may be delayed in FDH resulting from a fibroblastic defect.


The pyloric atresia-junctional epidermolysis bullosa syndrome. Report of a case and review of the literature.

The concomitant occurrence of the two rare conditions of pyloric atresia (PA) and inherited epidermolysis bullosa (EB) is not as rare as would be expected. We collected 41 case reports in the world literature and add a personal case in which EB was investigated with modern methods and found to be a GB3-positive/non-Herlitz junctional variant. Our review of the PA-EB association discloses that it is an autosomal recessive inherited entity in which EB is of the junctional EB (JEB) subtype and PA is a primary manifestation rather than a scarring process secondary to JEB. The disease is thus better called "PA-JEB." Patients with the PA-JEB syndrome present, not uncommonly, with erosions and/or subepithelial cleavage in the respiratory, gastrointestinal, and urinary tracts. In addition, certain facultative features are unique to PA-JEB, ie, obstruction of the ureterovesical junction and high incidence of a peculiar form of aplasia cutis congenita. The GB3 monoclonal antibody was found normally expressed in three of three cases, excluding the Gravis-Herlitz variant, in spite of an unmatching EB phenotype in one case. Further studies are needed to assess which of the JEB varieties are present in the PA-JEB syndrome.


Congenital localized absence of the skin as a manifestation of epidermolysis bullosa.

Congenital localized absence of the skin has been observed in various subsets of inherited epidermolysis bullosa. Through electron microscopy and immunomapping, we attempt to clarify the relationship of congenital localized absence of the skin lesions to epidermolysis bullosa. The case of a child with epidermolysis bullosa simplex and congenital localized absence of the skin is presented. Electron microscopy and immunomapping of the areas of congenital localized absence of the skin and sites of skin fragility suggest that these lesions are pathogenically identical. After reviewing the literature, we believe that the term Bart's syndrome should be used to identify patients with any type of epidermolysis bullosa who present with localized congenital absence of the skin on the extremities.


Histologic features of paraneoplastic pemphigus.

We describe the histopathologic features of paraneoplastic pemphigus, a recently described autoimmune mucocutaneous disease associated with neoplasia. Complete evaluation for paraneoplastic pemphigus requires identification of the characteristic mucocutaneous eruption, tissue specimens for routine histologic and direct immunofluorescence evaluation, and identification of circulating autoantibodies with a unique specificity. Immunoprecipitation from keratinocytes reveals a characteristic complex of four proteins with the circulating antibodies. Various neoplasms have been identified in patients with paraneoplastic pemphigus. We reviewed 16 skin and oral mucous membrane biopsy specimens from six patients with paraneoplastic pemphigus confirmed by fulfillment of all criteria. Major features include epidermal acantholysis, suprabasal cleft formation, dyskeratotic keratinocytes, vacuolar change of the basilar epidermis, and epidermal exocytosis of inflammatory cells. Seven (44%) of 16 specimens displayed a unique combination of suprabasal acantholysis and dyskeratotic keratinocytes throughout the epidermis. These histologic findings correspond to those of the characteristic clinical lesions that are described as having features of pemphigus and erythema multiforme. Paraneoplastic pemphigus represents a unique clinical, histologic, and immunologic disease characterized by autoantibody production to desmoplakin I and desmoplakin II, bullous pemphigoid antigen, and, possibly, other antigens in the desmosomal complex. Recognition of the histologic features should prompt immunopathologic confirmation and evaluation for an occult neoplasm.


Vehicular traffic as a determinant of blood-lead levels in children: a pilot study in Mexico City.

The major determinants of blood-lead levels were studied in 90 children who attended an outpatient pediatric clinic in Mexico City. All children, who were from 1-10 y of age, were from homes for which socioeconomic status had been categorized as medium to high. Blood-lead levels ranged from 0.17 (standard deviation [SD] = 0.008) to 1.21 (SD = 0.06 mumol/l). The main determinant of blood-lead levels was place of residence. Children who lived on private streets (i.e., low-traffic areas) had a significantly lower blood-lead level than children who lived on large avenues and who resided close to main roads (p = .0001, r2 = .27). This observation documented high exposure levels among children who live in Mexico City and suggested that leaded fuel used in Mexico could play an important role in determining blood-lead levels in this population.


Repeated bone lead levels in Queensland, Australia--previously a high lead environment.

Bone lead levels (finger and tibia) were measured, both in vivo and in vitro, with an x-ray fluorescence technique. In vivo finger-bone lead levels of 105 volunteers were estimated and subsequently re-estimated after a 5-y period. In many instances, elevated levels in some of these individuals probably resulted from lead ingested during childhood (i.e., more than 60 y ago). A decline in finger-bone lead from the initial value was accompanied by a mean finger-bone lead half-life of 6.2 y (n = 25); many individual's half-life values were less than 3.0 y. Perhaps one reason for these low values is the special propensity of finger bone to resorption during the involutional period, at which time there are high levels of circulating parathormone.


Placental cadmium and birthweight in women living near a lead smelter.

It has been suggested that the accumulation of tobacco-derived cadmium (Cd) in the placenta is responsible for the adverse effect of cigarette smoking on infant birthweight. We chose to test this hypothesis; therefore, we studied a population of nonsmoking pregnant women who were exposed to low levels of smelter-derived Cd and a group of nonexposed women. A higher mean placental Cd concentration (p less than .0007) was found in the exposed women (n = 106), compared with those who were not exposed (n = 55); the observed Cd concentrations were comparable to concentrations reported previously for smoking and nonsmoking women, respectively. Least squares multiple regression (controlling for potentially confounding variables) revealed no association between placental Cd and birthweight. It was, therefore, concluded that the effect of smoking on birthweight was not mediated through Cd.


Reported symptom prevalence rates from comparison populations in community-based environmental studies.

National, regional, state, and county rates of mortality and morbidity are frequently used as reference values in epidemiologic studies. However, baseline information on self-reported symptom rates is currently unavailable. This information is potentially very useful as outcome measures in environmental and occupational epidemiologic studies in which symptoms may be the most sensitive measure of effects of low-level chemical exposure. Comparison populations (n = 934 adults) from three community-based studies were used to determine 1-y symptom prevalence rates. Symptoms rates varied greatly between one study, in which a self-administered questionnaire was used, and the two studies for which data were collected via a similar questionnaire administered by trained interviewers. Four symptoms were selected for detailed analysis of covariates associated with symptom reporting: (1) skin irritation, (2) eye irritation, (3) sleep disturbance, and (4) fatigue. Logistic regression analysis of symptom reporting, by demographic data, and a risk perception variable suggested that the prevalence of symptoms varied with gender, race, and degree of respondent's environmental concern. The results from two of three surveys provide rates that might be used as reference rates in a community-based survey if resources are not available to permit the study of a comparison population. These rates may also provide a quick, initial impression prior to embarking on a full-scale epidemiologic study.


Investigation of a reported cluster of bladder cancer cases in the Pottstown/Phoenixville area of Pennsylvania.

A urologist in Phoenixville, Pennsylvania, noted an apparent excess of invasive bladder cancer cases in his practice area during 1988 and 1989. Background incidence data for the local area were derived from state Cancer Registry statistics. Seventeen additional cases were noted during review of local hospital tumor registry data. Exposure evaluation included complete occupational histories for 15 index cases and correlation of residential histories with a review of local industries, water quality data, and toxic waste sites. The data were compared with incidence data from 1984 and 1985, and no increase in bladder cancer incidence for this area in 1988 and 1989 was evident. There was, however, a higher bladder cancer incidence among white males in the study area and Chester County, compared with Pennsylvania as a whole. Residential histories and environmental analysis did not reveal a common environmental carcinogen. A high incidence of occupational exposure to suspected bladder carcinogens was noted. In addition, all but 4 of the index cases smoked cigarettes. The study was limited by an extreme paucity of water supply analysis data. Effective environmental monitoring would promote more effective research into environmental carcinogenesis.


Gastric cancer mortality and nitrate levels in Wisconsin drinking water.

The association between nitrate levels in public and private sources of drinking water and gastric cancer mortality in Wisconsin was investigated in a case-control study. All gastric cancer deaths of Wisconsin residents from 1982 through 1985 were compared with deaths from other causes (controls), and nitrate levels in the home drinking water of these residents were determined. Nitrate measures for public sources were obtained from historic nitrate data from municipal sources that existed in 1970. Nitrate measures for private water sources were obtained by testing the wells individually at the existing residences. Controls were matched individually to gastric cancer cases with respect to sex, year of birth, year of death, Wisconsin birth, and Wisconsin residency at the time of death. Matched-pair analyses were performed on the paired data, and the following levels of nitrate-nitrogen exposure were used as indicators of exposure: 0.5, 2.5, 5.0, and 10.0 mg/l. Matched-pair analysis was also performed for which private water supply constituted exposure. Odds ratios and 95% confidence intervals were, respectively, 0.92 (0.75, 1.12); 0.97 (0.74, 1.35); 0.86 (0.69, 1.08); 1.50 (0.12, 18.25); and 1.09 (0.82, 1.47) for exposure to private well-water sources. These results did not indicate an increased risk of gastric cancer at any level.


Immune alterations in humans exposed to the termiticide technical chlordane.

Lymphocyte phenotype frequencies and in vitro functional assays were studied in 27 individuals who had been exposed to technical chlordane in their homes or at their places of work. A control group consisted of 118 individuals who were similar to the exposed group with respect to age and sex distribution, and who had not knowingly experienced exposure to technical chlordane, was chosen for study. A significantly increased frequency of cortical thymocytes in the circulation (CD1) (p less than .001) and a decreased frequency of the suppressor-inducer phenotype CD45RA/T4 (p less than .01) were noted in the exposed group. Both kappa and lambda light-chain frequencies were elevated (p less than .01). Proliferative responses to the three mitogens tested, PHA, CONA, PWM, and to allogeneic lymphocytes in the mixed-lymphocyte culture assay were significantly lower than in controls (p less than .01). Responses in assays of the natural killer function were not significantly different from those of controls, but Fc receptor-associated K cell function was significantly greater than responses in controls. Of 12 individuals tested for evidence of autoimmunity, 11 demonstrated some increased titer of a form of autoantibody. This cluster of significant findings demonstrates the emergence of aberrant peripheral T and B cell regulation and a potential for autoimmune activation, detectable up to 10 y after exposure to technical chlordane.


Assessment of acute health effects from the Medfly Eradication Project in Santa Clara County, California.

Surveys were performed to assess the acute health effects of aerial application of malathion bait over a large urban area. Three indirect attempts to assess utilization of health care services were made: (1) surveillance of a major hospital emergency department was undertaken, (2) ambulance dispatches were reviewed, and (3) emergency treatments for asthma at a university hospital were reviewed. These assessments were negative but insensitive. Prevalence of self-reported symptoms was assessed with two surveys that were subject to severe time constraints. Personal interviews of the same individuals, before and after the spraying, were conducted: one was conducted by telephone and the other by residential visit. Results indicated no detectable increase in acute morbidity. Also, after the spraying, there was a decrease in anxiety-related symptoms.


Decontamination of human skin exposed to 2,3,7,8-tetrachlorodibenzo-p-Dioxin (TCDD) in vitro.

Human post-mortem skin was exposed in vitro to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at 32 degrees C, under controlled humidity. In one-half of the samples, damage to the surface of the skin was simulated by stripping of the stratum corneum. After incubation with TCDD for 100 min, four different decontamination protocols were performed: (1) the sample was wiped with dry, adsorbent material (cotton balls); (2) a 10-min topical treatment with mineral oil was followed by dry wiping with cotton balls; (3) a 10-min topical treatment with mineral oil was followed by wiping with acetone-soaked cotton balls; and (4) the sample was washed with water and soap. After decontamination, skin samples were incubated (up to 300 min) again at 32 degrees C. One set of both intact and stripped TCDD-exposed skin samples was incubated for 300 min--absent decontamination--and was used as a control. Mineral oil treatment and acetone wipes, or water and soap, were effective in reducing (i.e., about two-fold) the amount of TCDD in the stratum corneum of intact skin. Mineral oil plus dry wipes reduced the amount of TCDD in the stratum corneum by about one-third, whereas dry wiping alone was ineffective. All protocols, however, were similarly effective in reducing the amount of TCDD in the epidermis and upper dermis; TCDD concentrations were decreased locally by factors of up to ten. In the lower dermis, a minimal effect of the decontamination procedures was observed.(ABSTRACT TRUNCATED AT 250 WORDS)


A study of current residents' knowledge of a former environmental health survey of their community.

A follow-up survey of current residents who live near the McColl waste disposal site was conducted to assess community knowledge of an environmental health survey that occurred in the same neighborhood 7 y earlier. Of the 193 eligible adults who participated in an interview (response rate = 73.4%), 35.8% reported having heard of the 1981 health survey; 48% of these (n = 33) reported hearing or seeing the results of the survey. Knowledge of the earlier survey was reported by 34.6%, 40.6%, and 35.7% of respondents in the high-exposure, low-exposure, and comparison areas, respectively. Recall was significantly associated with age (i.e., greater than 55 y), college education, and residence prior to 1981. Our findings suggest that both long-term and recent residents in the study areas know about the McColl waste-disposal site, but the majority of current residents in this sample do not know that the health of the community was assessed in 1981 and that no serious health effects associated with the site were identified. Future efforts to communicate findings of similar health studies should focus on individuals who have less education and on communication with residents who move into an area after a study has been conducted. Creative public participation and media relations should be developed to assure that the results of such studies reach the public.


Breath ammonia depletion and its relevance to acidic aerosol exposure studies.

It is thought that gaseous ammonia in breath neutralizes acidic air pollution and thereby potentially mitigates the pulmonary effects of pollution. The efficacy of breath ammonia depletion methods reported in recent acid aerosol exposure-health response studies was investigated. Fourteen subjects (21 to 54 y of age) performed one or more of the following hygiene maneuvers: (a) acidic oral rinse (pH 2.5); (b) tooth brushing, followed by acidic oral rinse; (c) tooth brushing, followed by distilled water rinse; and (d) distilled water rinse. Initial ammonia levels ranged from 120 to 1,280 ppb (147-1,570 micrograms/m3). Acidic rinsing resulted in an immediate 90% reduction in exhaled ammonia in all subjects, and a return to 50% of baseline levels occurred within 1 h. Depletion that resulted from tooth brushing or distilled water alone was not significant. It was concluded that acidic oral rinsing is an effective method of reducing airway ammonia, but repeated oral rinsing may be required to maintain consistent, low-breath-ammonia conditions during acid aerosol exposure studies.


Calcium antagonists and renal protection. Current status and future perspectives.

During the past decade, considerable attention has been focused on the effects of calcium antagonists on renal function. Direct in vivo and in vitro observations in diverse experimental models indicate that calcium antagonists antagonize preglomerular vasoconstriction. Furthermore, calcium antagonists are postulated to have additional properties that contribute to their ability to afford renal protection. These putative mechanisms include the ability to retard renal growth, and possibly to attenuate mesangial entrapment of macromolecules, and to attenuate the mitogenic effects of diverse growth factors. Although the clinical implications of the above-mentioned findings have not been fully delineated, the results of recent clinical trials indicate that calcium antagonists exert salutary effects on renal function in clinical settings characterized by impaired renal hemodynamics, including transplant-associated acute renal insufficiency and, possibly, cyclosporine nephrotoxicity. Evidence has accrued suggesting that calcium antagonists may also be protective against acute radiocontrast-induced nephrotoxicity. Finally, the renal hemodynamic and natriuretic effects of calcium antagonists commend their use as antihypertensive agents in the management of essential hypertension, renovascular hypertension, and transplant-associated hypertension.


Effect of benomyl toxicity on some liver constituents of albino rats.

Weanling albino rats were fed 0-600 mg/kg body weight methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate (benomyl) for 7 d, and effects on protein, glycogen, and vitamin A constituents were recorded. Doses fed in rat chow were 0, 40, 80, 125, 165, 200, 240, 280, 320, 360, 400, 440, 480, 520, 560, and 600 mg/kg body weight. There was a dose-dependent decrease in the concentration of liver constituents, of which glycogen decreased the most. Histopathological findings included cellular swelling and edema of the liver, kidney, and spleen.


Current status of lung transplantation for cystic fibrosis.

Lung transplantation has emerged as an acceptable option for the management of cystic fibrosis patients with endstage lung disease. Heart-lung transplantation and, more recently, double lung transplantation have been successfully performed in this group of patients. The choice of operation, so far, has been based on the surgeon's preference and experience as well as the cardiac function of the patient. Each of the procedures has advantages and disadvantages. This article reviews the current worldwide experience in lung transplantation for patients with cystic fibrosis and highlights the controversies involved in the selection of patients and procedure.


Optimal therapeutic level of heparin therapy in patients with venous thrombosis.

Audits of heparin sodium therapy suggest that heparin administration is fraught with difficulty. The literature indicates that the current clinical practice of intuitive ordering of heparin results in inadequate therapy because of fear of bleeding. The importance of exceeding the lower limit of the therapeutic range has been strongly supported by findings of prospective clinical trials. Firm evidence indicates that failure to exceed the lower limit is associated with unacceptably high rates of recurrent venous thromboembolism. By comparison, evidence supporting the risk of exceeding the upper limit of the therapeutic range is weak. The purposes of this study were (1) to validate prospectively an approach designed to minimize the proportion of patients receiving subtherapeutic doses of heparin and (2) to determine the effectiveness and safety of decreasing the heparin dosage infused on the basis of activated partial thromboplastin time (APTT) prolongation reflecting both heparin and warfarin sodium effects. We performed a randomized double-blind study evaluating a prescriptive approach to heparin administration in patients receiving heparin or heparin with warfarin. Thromboembolic and bleeding complications were objectively documented. Only 1% and 2% of patients had subtherapeutic heparin levels for 24 hours or more in the heparin and combined groups, respectively. Recurrent venous thromboembolism occurred infrequently in both groups (7%). Sixty-nine (69%) of 99 patients receiving combined therapy had supratherapeutic values, compared with 24 (24%) of 100 receiving heparin; bleeding complications occurred in 9% and 12%, respectively. Our findings demonstrate that no association exists between supratherapeutic APTT responses and bleeding, which is in direct contrast to the observed association between subtherapeutic APTT responses and recurrent venous thromboembolism.


Severity of illness and resource use differences among white and black hospitalized elderly.

Disparities between races in access to health care services continue to exist. We examined differences in illness severity, charges, and length of stay between white and black hospitalized elderly. The study sample was 1184 elderly patients. Data using the Computerized Severity Index were collected for admission, maximum throughout the stay, and discharge. Blacks were admitted significantly more severely ill than whites. At discharge, 96% were severity level 1. At each severity level, blacks had significantly shorter hospitalizations and lower charges. The differences were not explained by disease, surgery, age, sex, hospital, and payer. Admission severity disparities may exist because of patients' decisions to seek care or provider admitting practices. We need to study whether differences in severity-adjusted resource use are due to underutilization for blacks or overutilization for whites.


Chronic fatigue syndrome criteria. A critique of the requirement for multiple physical complaints.

The purpose of this study was to test the hypothesis that the patients with chronic fatigue who have the highest number of medically unexplained physical symptoms over their lifetime would also have the highest prevalence of current and lifetime affective and anxiety disorders, lifetime affective symptoms, and the most functional disability. A further goal was to use this information to modify the current case definition to better identify a subgroup of patients with chronic fatigue syndrome who are less likely to have psychiatric illness. Two hundred eighty-five consecutive patients with chronic fatigue were interviewed with the National Institute of Mental Health Diagnostic Interview Schedule and completed four self-rating questionnaires measuring psychologic distress, functional disability, and the tendency to amplify symptoms. Based on previously published data, patients were divided into four groups with a progressively higher number of lifetime medically unexplained physical symptoms. The prevalence of current and lifetime psychiatric disorders, lifetime psychologic symptoms, and extent of functional impairment was then compared in these four groups of patients. The prevalence of current and lifetime psychiatric diagnosis and lifetime depressive symptoms increased linearly with the number of lifetime physical symptoms that the patient experienced. The extent of impairment in activities of daily living and the tendency to amplify symptoms also increased linearly with the number of medically unexplained physical symptoms. The patients with the highest numbers of medically unexplained physical symptoms had extraordinarily high rates of current and lifetime psychiatric disorders. These data suggest that the current case definition for chronic fatigue syndrome inadvertently selects for patients with the highest prevalence of lifetime psychiatric diagnoses. A recommendation based on these results is to modify the case criteria for chronic fatigue syndrome to include patients with fatigue and few physical symptoms and to identify and consider excluding patients with high numbers of physical complaints.


Angiographic patterns and severe coronary artery disease. Exercise test correlates.

In a Veterans Affairs Medical Center, we studied 607 male patients to determine whether patterns and severity of coronary artery disease could be predicted by means of standard clinical and exercise test data. We found significant differences in clinical, hemodynamic, and electrocardiographic measurements among patients with progressively increasing disease severity determined by angiography. Left main disease produced responses significantly different from those of three-vessel disease only when accompanied by a 70% or greater narrowing of the right coronary artery. Discriminant function analysis revealed that the maximum amount of horizontal or downsloping ST depression in exercise and/or recovery was the most powerful predictor of disease severity, with 2-mm ST depression yielding a sensitivity of 55% and a specificity of 80% for prediction of severe coronary artery disease (three-vessel disease plus left main disease). Patients with increasingly severe disease also demonstrated a greater frequency of abnormal hemodynamic responses to exercise.


Gaps in the anion gap.

To review limitations of the use of serum anion gap in clinical practice. Original reports and reviews. Sources containing the most recent pertinent information. Theoretical and practical limitations beset the use of serum anion gap. Awareness of these limitations reduces but does not eliminate wrong diagnoses based on the anion gaps. Serum anion gap has a limited value in the differential diagnosis of acid-base disorders and can be misleading.


Risk factors associated with complaints of insomnia in a general adult population. Influence of previous complaints of insomnia.

Insomnia is a common complaint both in the general population and also in physician's offices. However, risk factors for the development of insomnia complaints have not been completely identified. To identify population characteristics associated with increased prevalence of insomnia complaints, we surveyed a large general adult population in 1984 through 1985. We evaluated the relationship among current complaints of initiating and maintaining sleep and obesity, snoring, concomitant health problems, socioeconomic status, and documented complaints of difficulty with insomnia 10 to 12 years previously. The strongest risk factor for complaints of initiating and maintaining sleep was previous complaints of insomnia (odds ratio, 3.5). In addition, female gender (odds ratio, 1.5), advancing age (odds ratio, 1.3), snoring (odds ratio, 1.3), and multiple types of concomitant health problems (odds ratios, 1.1 to 1.7) were all risk factors associated with an increased rate of complaints of initiating and maintaining sleep. Complaints of insomnia tend to be a persistent or recurrent problem over long periods of time. Female gender, advancing age, and concomitant health problems also are important risk factors.


Pneumococcal endocarditis in Alaska natives. A population-based experience, 1978 through 1990.

Streptococcus pneumoniae is an uncommon cause of infective endocarditis (IE). We studied the presentation, microbiologic characteristics, and outcome of nine cases of S pneumoniae IE during a 12 1/2-year period in a population of 75,000 indigenous Alaska Natives (ANs), who have documented high rates of invasive pneumococcal disease. Fifty-six cases of IE occurred in ANs statewide during 1978 through 1990. Medical records of all nine confirmed cases of S pneumoniae IE were reviewed. Incidence rates for S pneumoniae IE and all IE were calculated. Alaska Natives experience S pneumoniae IE as a fulminant illness, with acute aortic valve insufficiency (100%) frequently requiring emergent valve replacement, S pneumoniae meningitis (56%), and death (33%). No patient with S pneumoniae IE had known preexisting heart disease, and the most common underlying disease was alcoholism (56%). Pneumonia was diagnosed and embolic complications were suspected in 33%. All five S pneumoniae isolates examined were penicillin sensitive and were of serotypes included in the pneumococcal vaccine. Pneumococcal IE accounted for 15.8% of all IE diagnosed in ANs. Age- and sex-adjusted incidence rates for IE of all causes and S pneumoniae IE were 8.5 and 1.5 per 10(5) persons per year, respectively. During 1986 through 1988, 4.3% of AN adults diagnosed with S pneumoniae bacteremia developed S pneumoniae IE. Pneumococcal endocarditis in all but one AN case required emergent valve replacement and had a 33% mortality. The annual incidence rate of S pneumoniae IE in this population was five to 37 times higher than contemporary rates elsewhere. Increased efforts to prevent pneumococcal disease in ANs appear warranted. Clinicians everywhere should anticipate the possible development of S pneumoniae IE in adult patients with pneumococcal sepsis, especially with meningitis, even with previous vaccination and prompt adequate antimicrobial therapy.


The prevalence of risk factors for venous thromboembolism among hospital patients.

This study provides an estimate of the prevalence of risk factors for venous thromboembolism among hospital patients. The presence of risk factors for venous thromboembolism was determined from a retrospective review of the medical records of 1,000 randomly selected patients in 16 acute care hospitals in central Massachusetts. The most common risk factors for venous thromboembolism were age 40 years (59%) or more, obesity (28%), and major surgery (23%). The average number of risk factors increased with increasing age. One or more risk factors for venous thromboembolism were present in 78% of hospital patients, two or more in 48%, three or more in 19%, four or more in 6%, and five or more in 1%. Risk factors for venous thromboembolism are common among hospital patients, suggesting that prophylaxis should be widely employed. The cost-effectiveness and risk benefit of prophylaxis is well established in patients undergoing major surgery. Further studies are needed to confirm the benefit of prophylaxis in patients with nonsurgical risk factors for venous thromboembolism.


Cost, uncertainty, and doctors' decisions. The case of thrombolytic therapy.

To examine the prescribing patterns and predictors of physician choice in the selection of intravenous thrombolytic therapy for the treatment of acute myocardial infarction. Survey of a random sample of 250 California cardiologists between July 1989 and February 1990. The adjusted response rate was 66%. For a patient presenting within 30 minutes after the onset of an uncomplicated acute anterior-wall myocardial infarction, 98% of respondents reported that they would prescribe a thrombolytic agent, 79% chose tissue plasminogen activator, and 21% chose streptokinase. Users of tissue plasminogen activator were nine times more likely than streptokinase users to perceive tissue plasminogen activator as superior for early coronary artery recanalization, although most users of tissue plasminogen activator and streptokinase perceived no difference between the two agents for improvement in ejection fraction and mortality. Estimates of side effects did not distinguish the two groups. Users of streptokinase were eight times more likely to practice in a health maintenance organization than were users of tissue plasminogen. For a self-paying patient, 36% of users of tissue plasminogen activator said that they would switch to streptokinase, and 27% would switch for a patient insured by Medicaid. These results indicate that physicians place great emphasis on surrogate end points. Physicians vary in their willingness to use more expensive therapies over cheaper alternatives, even when their perceptions of the relative risks and benefits are similar. The patient's insurance status and the provider's practice setting may exert an important influence on doctors' clinical choices.


Assessing medical interview performance. Effect of interns' gender and month of training.

Observation of history taking is commonly used to assess interviewing skills in medical internships, yet specific interviewing problems are infrequently documented. We evaluated videotaped recordings of 83 complete medical histories of new patients for content and questioning technique. Frequent deficiencies were found in history of medication compliance, gynecologic and psychiatric history, use of open questions, and mental status examination. The initial segments of 48 interviews were evaluated, and in 44% the patient was not allowed to complete their opening statement of concerns. Female physicians allowed fewer patients to finish their opening statement, and physicians at the end of the internship permitted the patients less time to express their concerns. Structured evaluation of complete histories reveals frequent interviewing problems as well as possible important effects of physician gender and length of training.


Mortality in intensive care patients with respiratory disease. Is age important?

Age has been proposed as a criterion for health care rationing. However, the relationship of age and other prognostic factors to in-hospital mortality in older patients is unclear. The purpose of this study was to examine the effect of age on hospital mortality for patients admitted to the intensive care unit. This historical prospective study examined 3050 admissions of patients aged 50 years and older with disease of the lower respiratory tract to intensive care units in 78 hospitals in the United States during an 18-month period (July 1987 through December 1988). The association of age with hospital mortality was examined by means of a multiple logistic regression model that included age, gender, primary discharge diagnosis, severity, and comorbid diseases. Variables significantly predictive of in-hospital mortality included age, severity of illness, diagnosis, and a history of chronic obstructive pulmonary disease. In contrast, gender, diabetes mellitus, congestive heart failure, angina, and stroke/transient ischemic attack were not significant predictors of mortality. Predicted mortalities varied from 0.7% to 40.7% in 50-year-old patients and from 5.5% to 78.6% in 90-year-old patients. Chronological age is independently associated with in-hospital mortality in patients with disease of the lower respiratory tract admitted to an intensive care unit. However, the clinical importance of this relationship is modulated by other variables, such as the primary diagnosis, the presence of comorbid conditions (chronic obstructive pulmonary disease), and the severity of the acute illness, such that use of age alone is not sufficient to predict hospital outcome.