[The effect of exogenous whole-body hyperthermia on humoral immunity].

We investigated the proliferative responses of spleen cells (SC) to polyclonal mitogens lipopolysaccharide (LPS) and pokeweed mitogen (PWM), immune responses to sheep red cells (SRC) in mice undergoing hyperthermia. There were increased proliferative responses of lymphocytes to PWM if we used mice having rectal temperature 42 degrees C. Thermal shock in mice was accompanied by suppression of immune response. If we used mice suffering from hyperthermia (43-44 degrees C) for 20 minutes; there were decreased proliferative responses of lymphocytes to PWM or LPS for 10-30 days. We observed low immune response to sheep red cells in mice for 5-20 days. The changes of immune response were not revealed on the 40th day after induction of hyperthermia in mice.


[The immunohistochemical study of trophoblast beta 1-globulin expression in cancer and in the mucosa of the large intestine].

The expression of pregnancy-specific beta-1-globulin (SP1) was studied in cancer-affected and nonaffected colon mucosa. The antigen was revealed in 19 out of 50 (38%) cases of carcinoma and in 1 out of 4 cases of ulcerative colitis. SP1 was found neither in noncancer colon mucosa nor in transitional mucosa and adenomas. The antigen was detected in the epithelium and stromal macrophages of carcinoma. SP1-positive cells were located mainly in the sites of tumor invasion. The results allow considering SP1 the tumor marker suitable for immunohistochemical diagnosis of colon cancer.


[The chemiluminescence reactions of the blood neutrophils and of peritoneal exudate cells in Syrian hamsters to the intraperitoneal administration of cellular and microbial materials].

The luminol-dependent chemiluminescence (CL) activity of peritoneal exudate cells and blood neutrophils of Syrian hamsters inoculated intraperitoneally with heat-inactivated microbial particles of Candida albicans, (C. albicans), heated irradiated normal cells and native or heated irradiated malignant tumor cells was studied. The inoculation with particles of C. albicans and heated normal cells induced significant activation of CL of peritoneal exudate cells, but did not influence the CL reaction of blood neutrophils. The inoculation of animals with nonheated irradiated tumor cells led to increase of CL response of both peritoneal exudate cells and blood neutrophils. The inoculation with heated irradiated tumor cells did not activate CL of peritoneal exudate cells and led to slight, but long-lasting decrease of CL response of blood neutrophils.


[The effect of ascitic fluid globulins on the growth of leukemia P388/DOX and Ehrlich's carcinoma in mice].

The study was performed to investigate the effect of ascitic fluid globulins of tumor on tumor growth and life span of mice. The globulins are shown to shorten the life span of Ehrlich tumor mice from 86.8 to 61.8 days, to increase 3-5-fold the growth rate of Ehrlich carcinoma and P388/DOX tumor. It was found that globulins of ascitic fluids and serum globulins of tumor have equal effects of tumor growth. It is proposed to use globulins of ascitic fluid to study the globulin role in tumor growth.


[The effect of a clover extract on the proliferation of human and murine lymphocytes in vitro].

The extracts were prepared from meadow clover harvested at the stages of blossoming and budding. The major biological activity of such extracts is represented by flavonoid compounds. The influence of extracts on the proliferation of peripheral blood mononuclear cells obtained from healthy donors and of inbred mouse splenocytes in vitro was analyzed. Both preparations stimulated cellular proliferation. The lever of stimulating activity correlated with the stage-dependent concentration of flavonoids.


[Leukocytolysis and phagocytosis under hyperosmotic conditions].

PAN and leukocytolysis were measured in dog blood placed in hypo- and hypertonic solutions of glycerin and glucose (1:10). It was found that leukocytolytic activity of the substances depends on equimolar concentrations of nonelectrolytes. It is more pronounced in hypo- than in hypertonic conditions. Glycerin is 3-5-times more active than glucose. In concentrations 2.0 M for glycerin and 0.5 M for glucose leukocytolysis is less active. Mononuclears are more resistant than neutrophils in strong solutions. PAN increased by 11-16% in hypotonic solutions. Strong glycerin solutions reduce PAN less than glucose which stimulates the digestive activity. The results can be of use in specific leukolysis tests to diagnose drug allergy.


[The seasonal characteristics of the circadian rhythm of hypoxic resistance and convulsive resistance].

Hypoxic and convulsive resistances have daily rhythms, the pattern of which depends on the year season. Latent period of occurrence of epileptic seizures and time of life at the "height" of 11,000 m above the sea level undergo similar changes in autumn and spring. In winter minimal similarity between daily dynamics of each of these resistances and analogous ones in other seasons is observed, but rhythms of tolerance to hypoxia are maximally synchronized with the rhythms of convulsive resistance. In autumn hypoxic and convulsive resistances are minimal. Maximums of these indices are observed in different seasons: for tolerance to hypoxia it is summer, for convulsive resistance--spring.


[The nature of the distribution of the individual circulatory biorhythms in schoolchildren (7 to 17 years old) living at different altitudes in the mountains].

Data on individual biorhythms are presented for 270 children aged 7-17 living in the regions situated at 760, 1700 and 2850 m above the sea level. Central hemodynamics was measured by Kubicek et al. method 6 times a day every 6 hours. The analysis of the pilot evidence was conducted by cosinor program, then an original method was introduced which allowed evaluation of the degree of biorhythmologic dispersion in the samples. The findings indicate a significant increase in hemodynamic biorhythm polymorphism and broadening of "biorhythmological norm" in children population aged 7-17 under the middle and high mountain conditions.


[The radioisotope labelling of thrombocytes using a monoclonal antibody against membrane glycoproteins IIb-IIIa and the measurement of thrombocyte adhesion/aggregation on the substrate surface].

A new method for platelet labeling based on binding of monoclonal antibody to human platelets has been suggested in this study. Monoclonal antibody VM16a against membrane glycoproteins IIb-IIIa was labeled by 125I and then incubated with platelets. About 70% of added antibody was bound when it was used at the concentrations corresponding to the linear part of the concentration curve (0.5 and 1.0 micrograms/ml). Due to high efficiency of binding 125I-VM16a-labeled platelets were used for the measurement of adhesion/aggregation to the substrate in platelet-rich plasma without washing of the free label. Experiments with washed platelets double labeled with 51Cr and 125I-VM 6a showed high correlation between the data obtained with both labels. The method of platelet labeling has been applied for the assessment of drug action on platelet adhesion/aggregation. Measurements were performed in platelet-rich plasma and adhesion/aggregation was stimulated by ADP and analogue of thromboxane A2, U46619. It was shown/that antianginal drug trapidil strongly inhibited and antiatherogenic drug probucol did not affect platelet adhesion/aggregation stimulated by both agonists.


[The permeability of the barrier of the gastrointestinal tract for the macromolecules of polyethylene glycol-4000: an assessment of the mechanism and its reproducibility].

Polyethylene glycol (PEG)-4000 is proposed as a tracer of intestinal macromolecular permeability. The reproducibility of permeability testing with PEG-4000 and the mechanism of its penetration through intestinal mucosa were studied in adult rats. Permeability measurement for PEG-4000 was reproducible when repeated twice for 2 days. This makes it possible to repeat PEG-4000 permeability testing before and after any experimental impact on the intestine. I.p. administration of colchicine to rats (125 micrograms/100 g b. w.) significantly inhibited intestinal absorption of PEG-4000 fed to the animals 3 hours later. Hence, PEG-4000 penetration through the intestinal mucosa is mediated by the system of enterocyte cytoplasmic microtubules. Mucosal permeability for PEG-4000 may be consequently considered as a valuable model of permeability for protein macromolecules.


[The ultrastructural reorganization of the neurons in some brain formations during the deprivation of paradoxical sleep].

Electron microscopy was used to study intracellular changes in the dorsal hippocampus, lateral hypothalamic nucleus and pontine reticular formation of rats after 96-hour paradoxical sleep deprivation. It was found that compensative-accommodative processes predominate in the majority of neurons. At the same time destructive changes are detected in some cells. In changed neurons the ultrastructural signs of damage to protein-synthesizing apparatus were observed. These changes can be as a result of disturbances of protein biosynthesis.


[The marker histochemical detection of glucose-6-phosphate residues in the human placenta].

Glucose-6-phosphate residues were revealed by fine structural analysis using glucose-6-phosphate dehydrogenase-gold conjugate. In human mature placenta specific staining was detected over the stroma of placental villi. Colloidal gold particles were found over the collagen fibrils and reticular lamina of basal membrane. Syncytiotrophoblast cells, fibroblasts, endothelial cells of fetal capillaries avoided labelling. Nucleated blood cells and thrombocytes inside the lumen of fetal capillaries demonstrated intense staining. The present investigation demonstrates histochemically the process of extracellular glycosylation. Glycated collagen fibrils formed channels inside the stroma of placental villi.


[The reactivity of the circulating neutrophils in human peripheral blood].

Using cytochemical, biochemical and disc-electrophoretic methods, the degree of extracellular secretion of peroxidase-containing neutrophil granules has been investigated as an index of their functional activity when in contact with antigens of extra- and intra-circulation. It was established that in in vitro contacts of neutrophils with alive and killed microbe culture St. aur., the quantity of the granules in the cells decreased as well as the enzyme activity in them. This is partially due to extracellular secretion of the granules content confirmed by the presence of peroxidase fractions in the solution. Similar results have been obtained for circulating neutrophils and serum of patients with acute pneumonia at the height of the disease. It is hold that antigen-induced extra- and intracellular neutrophil degranulation in the peripheral human blood reflects functional activity of the neutrophils.


[Leukocytic shifts following pancreatic resection with a plasma scalpel and cryodestruction].

Two series of experiments were carried out on dogs. In the first series, blood leukocytes count was studied after resection of the pancreas using plasma scalpel. The resection caused two-phase leukocyte reaction: neutrocytosis (phase I) and leukocytosis involving mainly lymphocytes and monocytes (phase II). During the first 24 hours after the resection, a sharp increase of the leukocyte intoxication index (LII) was observed. The second series of experiments was performed using the combination of plasma scalpel and cryodestruction. The graphic curves denoted a sharp fall both in total leukocytic counts and in the different types of leukocytes which were plotted separately (neutrophils, eosinophils, etc.) This can be explained by the absence of the second (lympho-monocyte) reaction. Only a slight increase in LII occurred. These results reflect lower degree of the protection and adaptation reactions of leukocytes, this being in favor of a combination of plasma scalpel and cryodestruction during the operation.


[Structural-functional transformations of the ileal lymph nodes in pregnancy complicated by blood loss].

The microanatomic organization of iliac lymph nodes was studied in 24 pregnant Wistar rats (pregnancy term 21 days) after simulation of acute hemorrhage in them. A considerable decrease of a relative area occupied by a marginal sinus was revealed. This shows transport functional changes of lymph nodes in pregnancy complicated by hemorrhage.


[The astrocyte reaction to an experimental herpes infection].

The experimental research carried out on rabbits was aimed at determination of astrocytes reaction during brain inflammation caused by Herpes simplex virus. The study was made with the help of glia marker. Immunocytochemical findings showed that the earliest structural brain responses to the infection were changes in astrocyte glia. This was evident from the swelling and hypertrophy of vessel crus and from increased number of astrocytes around the vessels. Glia complexes (astrocyte agglomeration) were formed in the affected sites. During the exudative reaction the hyperplastic alterations of astrocytes were not observed. Later the injured spots of brain tissue were replaced by proliferating astrocytes. The conducted investigation has shown the astrocyte glia to be different during different stages of the infectious process. One may suppose that different subtypes of astrocytes response has place during each stage which should be further confirmed. One may also suppose that a similar alterations of astrocytes coincide with interferon and interleukin secretion by these cells. This is suggested to be a structural base of immune response of the brain.


Hemoglobin desaturation during sleep and daytime in patients with cystic fibrosis and severe airway obstruction.

Transcutaneous hemoglobin saturation by pulse oximetry was evaluated during sleep and for 2-3 h during the day in 31 patients with cystic fibrosis (median age 15.2 years; range 7.6-33.6 years) and severe airway obstruction. Pulse oximetry readings were analyzed as a cumulative percentage of time in which oxygen saturation was < 90% during both sleep and daytime. Each patient was also examined using clinical and radiological scores, spirometry and arterial blood-gas analysis. The agreement between arterial and transcutaneous saturation was evaluated in 29 patients. The difference between transcutaneous and arterial saturation was 2.4 +/- 2.0% and it increased as arterial saturation decreased. Clinical and radiological scores and spirometry parameters showed a poor correlation with both overnight and daytime desaturation. An arterial saturation < 94% may indicate a risk of consistent desaturation. This occurred for more than 50% of the time in 11 of 20 patients during sleep and in 5 of 20 patients during daytime hours.


The role of cow's milk protein intolerance in steroid-resistant nephrotic syndrome.

The role of cow's milk protein intolerance in steroid-resistant nephrotic syndrome was evaluated in 17 children. Cow's milk was excluded from the diet for at least 14 days without changing previously ineffective prednisone dosage. Six patients with minimal change or mesangial proliferation went into remission 3 to 8 days after elimination of cow's milk. After a period of 2-3 weeks of remission, cow's milk challenge was positive in three patients. After one year on a cow's milk-free diet, two of six patients became milk tolerant and are in remission of NS, one of six became steroid-dependent, two of six are still unable to tolerate cow's milk and are in remission on a cow's milk-free diet and one of six children was lost from observation. The role of cellular mechanisms in steroid-resistant nephrotic syndrome is suggested.


Ten-year prognosis for generalized infantile eczema.

Forty children treated in our hospital for generalized infantile eczema were re-examined at 11-13 years of age. In 7 (18%) children the eczema had disappeared and in 26 (65%) it had become less severe. Unrelated to dermatological status or gender, allergic rhinitis was diagnosed in 31 (78%) and asthma in 21 (53%) children. Only 8 children continued without either of these two conditions. All 32 children with allergic rhinitis and/or asthma showed at least one positive skin test reaction in a test panel of 11 common inhalant and food allergens compared with only 4 of 8 children without either allergic rhinitis or asthma (p < 0.001). Our results showed an improvement of dermatological status in most children with generalized infantile eczema but there was a high risk of a concomitant respiratory allergy and development of allergic rhinitis or asthma.


Autologous bone marrow transplantation in children with acute lymphoblastic leukemia.

We report 25 children with acute lymphoblastic leukemia (ALL) treated with purged autologous bone marrow transplantation (ABMT) at a single center. Two children with high-risk ALL were transplanted in first remission and 23 with relapsing ALL were transplanted in second (n = 21) or third (n = 2) remission. There was no procedure-related mortality. The median time to engraftment (i.e. to reach a polymorphonuclear cell count of 0.5 x 10(9)/l) was 25 days (range 16-45 days). Seven children relapsed, four within five months after ABMT: 18 of 25 children (72%) are in continuous complete remission after a median follow-up period of 50 months (range 5-71 months). The predicted long-term disease-free survival is 65% in the whole group and 61% in those transplanted after relapse. Relapse-free children returned to normal activities within three months after ABMT. The major side effects were development of cataract and gonadal insufficiency. We consider the results promising, but our data do not allow comparison with results reported from treatment with chemotherapy alone, since some of our patients were referred from other centers and represent a selected patient group. Long-term follow-up of well-defined patient populations is necessary to evaluate the effect of ABMT.


Growth during treatment of familial hypercholesterolemia.

Treatment of hypercholesterolemic children with restriction of dietary saturated fat may result in an inadequate supply of energy for normal somatic growth. We examined the growth of 30 children with familial hypercholesterolemia, some of whom were also treated with colestipol, a bile acid-binding resin. The median duration of treatment was 8.5 years in 13 patients on diet only, and 5.5 years + 3.5 years in 17 patients treated with diet followed by diet and colestipol. Statistically significant reductions in serum total cholesterol were obtained in both groups. The SD scores for both height/age and weight/age decreased by approximately 0.4 during dietary treatment (p < 0.05), but were not affected by treatment with colestipol. These results document the risk of growth retardation during dietary treatment of children with familial hypercholesterolemia.


Anaemia and macrocytosis--unrecognized features in cartilage-hair hypoplasia.

Cartilage-hair hypoplasia is an autosomal recessive osteo-chondrodysplasia which results in short stature, sparse hair and impaired cell-mediated immunity. In a study of 88 Finnish patients we found episodes of anaemia and/or macrocytosis during childhood in 86% of the patients. The reticulocyte index was always low in relation to anaemia. Bone marrow examination revealed decreased erythropoiesis in six of eight anaemic patients studied. Anaemia was most prevalent and severe during infancy. Spontaneous recovery occurred before adulthood in all patients except in three infants with fatal hypoplastic anaemia. Sixty-two percent of the patients had had lymphopenia and 24% neutropenia. Presence of anaemia significantly correlated to severity of immunodeficiency and growth failure and to presence of neutropenia. Disordered erythrogenesis is an integral feature of cartilage-hair hypoplasia and may, together with growth failure and immunodeficiency, reflect a generalized defect in cellular proliferation.


Magnetic resonance imaging of the brain structures in the posterior fossa in retarded autistic children.

Midsagittal magnetic resonance images of the brains of retarded autistic children were compared to those of non-autistic mental retardation patients and controls. We found that the whole brain stem and particularly two of its components (the midbrain and medulla oblongata) were significantly smaller in retarded autistic children and mental retardation cases than in control children. The pons area was significantly smaller in mental retardation cases as compared to control children but did not differ between autistic and control children. Moreover, there was no difference in the brain stem between retarded autistic children and mental retardation cases. We also noted no difference in the cerebellar vermis area among retarded autistic children, mental retardation cases and control children. The ratio of the midbrain to posterior fossa area was significantly smaller only in autistic patients. Although the significance of these results is unknown, further examination of autistic children with a normal IQ is necessary.


Low back pain and disability in 14-year-old schoolchildren.

In this cross-sectional prevalence study in 1503 14-year-old Finnish schoolchildren (n = 1503) low back pain was found to be the third most common form of pain interfering with schoolwork or leisure time during the past 12 months. The lifetime cumulative incidence of low back pain was 30% and that of sciatica 1.8%. Of the 417 pupils who had experienced low back pain at some time, 39% had suffered during the past month; 65% recovered in one month from the last pain episode, while 35.2% of those reporting disabling low back pain during the past year were aware of recurrent or continual pain. Thus, 7.8% (n = 107) of the whole population could be classified as "low back pain chronics": 86% of the low back pain chronics had trouble with at least one of the daily activities listed, most commonly with sitting at school. Excluding pain in the extremities or sciatica, girls reported various pains more commonly than boys. Moreover, girls reporting recurrent low back pain had more trouble with their daily activities due to pain than boys (p < 0.001), even though the recovery from the last pain episode took the same time in boys and girls. The pupils who had had sciatica at some time, in addition to recurrent low back pain, had more trouble with the 10 daily activities than others with recurrent low back pain (p = 0.014).


Guillain-Barré syndrome presenting with severe musculoskeletal pain.

Three children with Guillain-Barré syndrome are described who presented with musculoskeletal pain to an orthopaedic clinic or to a paediatric rheumatologist at a children's hospital. In each case, osteomyelitis of the spine was considered to be the most likely diagnosis and bone scans were performed in two of the three patients. Two of the three children required care in an intensive care unit, within hours of diagnosis. Outside of the specialty of neurology, the presentation of Guillain-Barré syndrome with severe muscle pain is not generally well known. With greater awareness of this particular presentation, dangerous delays in diagnosis and inappropriate investigations will be minimized.


Bone marrow examination before steroids in thrombocytopenic purpura or arthritis.

Corticosteroids were used to treat two children with presumed idiopathic thrombocytopenic purpura and one with juvenile rheumatoid arthritis without examination of the bone marrow. Of the two with presumed idiopathic thrombocytopenic purpura, one had Fanconi's anaemia and the other may have had aplastic anaemia. The third child had acute lymphoblastic leukaemia. The diagnosis of Fanconi's anaemia was delayed. A diagnostic and therapeutic dilemma was caused in the second case. In the third, delayed diagnosis and, perhaps, compromised outlook resulted. These three cases re-emphasize the well aired caveats about the diagnosis of idiopathic thrombocytopenic purpura and juvenile rheumatoid arthritis and provide further support for the arguments of those who believe that if corticosteroids are to be used to treat such children, their bone marrow should be examined first.


Microphthalmos with bilateral colobomatous orbital cyst accompanied by polycystic kidney disease and vacuolization of myeloid progenitor cells.

A case of microphthalmos with bilateral colobomatous orbital cyst accompanied by polycystic kidney disease and vacuolization of myeloid progenitor cells is presented. Association of these three entities has not been described previously in the literature.


Graves' disease, multinodular toxic goiter or toxic adenoma are the usual causes of hyperthyroidism in children as well as in adults. We report a case of hyperthyroidism due to TSH-secreting pituitary macroadenoma in an 11-year-old girl. The patient was admitted to the Endocrine Department for pituitary function evaluation, five months after transfrontal adenomectomy and pituitary irradiation for a macroadenoma. On admission the patient was clinically hyperthyroid and the work-up established a diagnosis of hyperthyroidism due to TSH-secreting adenoma (high levels of TSH in the face of hyperthyroidism, no TSH response to TRH stimulation, diffuse thyroid goiter without eye signs or pretibial myxedema). Of interest in this case was the fact that: (a) she is the youngest patient reported with hyperthyroidism due to a TSH-secreting macroadenoma and (b) hyperthyroidism was diagnosed after adenomectomy.


Cystic adult granulosa cell tumor causing precocious pseudopuberty in a six-year-old girl.

A very rare occurrence of adult granulosa cell tumor of the ovary (not of the juvenile type) causing precocious pseudopuberty in a six-year-old girl is described. An additional feature of interest was that the tumor appeared entirely cystic. To our knowledge, this condition in such a young premenarchal patient has not been reported previously.


Lumbar bone mineral content measured by dual energy X-ray absorptiometry in newborns and infants.

Dual energy X-ray absorptiometry (DXA), a non-invasive method for measuring small amounts of mineral, was used to assess the bone mineral content (BMC) and bone mineral density (BMD) of the lumbar spine (5 vertebrae) in 57 newborns (on day 1-2) and 22 infants (1-24 months of age). A modified high-resolution program (Hologic) allowed us to assess BMC and BMD with a precision higher than 2.4% and 1.5%, respectively. In newborns, BMC and BMD correlated positively with birth weight, body area, length and gestational age: r = 0.73, 0.71, 0.63 and 0.60, respectively, for BMC; and r = 0.59, 0.58, 0.54 and 0.53, respectively, for BMD. In infants, both BMC and BMD were highly correlated with weight, age, length and body area over two years (r = 0.94 or better in each instance). The data provide normal values for lumbar spine BMC and BMD in newborns (gestational age 31-40) and infants up to two years of age; DXA appears to be an excellent and safe tool for pediatric bone mineral measurements.


Effects of body movement restraint on cardiac response to auditory stimulation in sleeping infants.

When exposed to an unfamiliar and sudden noise, infant rodents may show an abrupt bradycardia, as part of a "fear-paralysis response". The response is enhanced by body movements restraint. To investigate if this reaction is seen in humans, 15 normal infants with a median age of 12 weeks were studied polygraphically. They were exposed to a 100-dB (A) white noise, while sleeping in REM sleep. Each infant was studied in both "unrestrained" and "restrained" conditions. Restraint of body movement was obtained by means of sand bags and tightly-binding bed sheets. During movement restraint, the infants had a significantly greater and earlier decrease in heart rate compared with during the unrestrained condition. No infant had a minimal heart rate less than 95 beats/min. The present observation raises questions about the possible unfavorable effects of tightly wrapped bed sheets around sleeping infants.


Narcotic and nicotine effects on the neonatal auditory system.

To evaluate narcotic and nicotine effects on the neonatal auditory system, brain stem auditory evoked responses were recorded in 15 infants prenatally exposed to both narcotics and nicotine (median gestational age 38.4 weeks, median birth weight 2820 g), in 15 nicotine exposed infants (gestational age 40.0 weeks, birth weight 3000 g) and in 24 healthy term infants (gestational age 40.1 weeks, birth weight 3310 g) who served as controls. Whereas nicotine-exposed and control infants were similar in all brain stem auditory evoked response measurements, narcotic/nicotine infants had bilaterally increased wave V latencies (left: p = 0.005; right: p = 0.04) and I-V intervals (left: p = 0.02; right: p = 0.01) when compared to controls. Our findings suggest that prenatal narcotic but not nicotine exposure negatively affects maturation or integrity of the neonatal auditory brain stem tract and that neither narcotic nor nicotine exposure is associated with hearing loss in the neonate.


Elevated calcitonin gene-related peptide in polycythemic newborn infants.

In this study, calcitonin gene-related peptide levels were measured in cord and at 16-36 h of extrauterine life in 43 polycythemic newborns; 20 healthy term infants were also studied as controls. Calcitonin gene-related peptide values were significantly higher in polycythemic neonates in comparison with controls both at delivery and at 16-36 h after birth. Five polycythemic (11.6%) infants who develop hypocalcemia had greater elevated calcitonin gene-related peptide concentrations. Our data suggest that calcitonin gene-related peptide may be implicated in the circulatory adaptation to extrauterine life. In polycythemic neonates, calcitonin gene-related peptide is probably increased to compensate for blood hyperviscosity; in some cases, high calcitonin gene-related peptide concentrations may induce hypocalcemia.


Low renal net acid excretion, high calciuria and biochemical signs of sodium deficiency in low-birth-weight infants fed a new low-phosphorus formula.

In 11 infants (birth weight greater than 1800 g) fed a new type of humanized formula with a low phosphorus (P) content (calcium (Ca) 11 mmol/l, P 7.2 mmol/l, sodium (Na) 8.3 mmol/l) biochemical parameters of blood, serum and urine were determined. In nine boys Ca and P balances were evaluated also. Renal net acid excretion was low (0.85 mmol/kg/day). Mean concentrations of P and Ca in urine were 0.34 mmol/kg/day (10.5 mg/kg/day) and 0.1 mmol/kg/day (4 mg/kg/day), respectively. In four infants, Ca concentration in urine was, however, greater than 0.15 mmol/kg/day) (6 mg/kg/day). In infants with birth weights greater than 1800 g fed the new, low-P formula, the low renal net acid excretion, the normal P and the high Ca concentrations in urine were comparable to term infants fed human milk. The high calciuria in several infants may be normal physiologic values. However, it remains to be established that the urinary solubility product of infants fed the new, low-P formula is in the same range as those for infants fed human milk. Unexpectedly, low urinary Na excretion (0.26 mmol/kg/day) and increased urinary excretion of aldosterone-18-glucuronide indicated biochemical evidence of Na deficiency secondary to low Na intake and a high weight gain. If the new, low-P formula is to be fed to infants with a birth weight as low as 1800 g. Na content should be higher than in mature human milk because of the often relatively higher weight gain.


Non-nutritive sucking does not increase blood levels of gastrin, motilin, insulin and insulin-like growth factor 1 in premature infants receiving enteral feedings.

Non-nutritive sucking in premature infants accelerates weight gain for unclear reasons. The effects of non-nutritive sucking on enteral hormone secretion may augment digestion and/or absorption of nutrients. Blood concentrations of gastrin, motilin, insulin and insulin-like growth factor-1 were measured before and 72 h after the initiation of nasogastric feedings in 21 premature infants randomly assigned to either a non-nutritive suckling or control group. Gastrin and motilin concentrations increased significantly after feedings in all infants (mean +/- SEM) (gastrin, 41 +/- 4 to 73 +/- 9 pg/ml, p < 0.01; motilin, 141 +/- 5 to 181 +/- 3 pg/ml, p < 0.01) Pre- and post-feed insulin concentrations were greater in the non-nutritive sucking group receiving bolus feeds than in control infants who were bolus-fed (P < 0.01). Non-nutritive sucking in premature infants does not appear to alter blood concentrations of motilin, gastrin, insulin or insulin-like growth factor-1 three days after initiation of feedings. If changes in the secretion of these hormones are induced by non-nutritive sucking, they may be at a local paracrine level.


Atrial natriuretic peptide in the preterm infant. Lack of correlation with natriuresis and diuresis.

We assessed the relation of atrial natriuretic peptide (ANP) to renal function on postnatal day 2 and day 5 in preterm infants. Plasma ANP concentration was measured by radioimmunoassay in two groups of preterm infants: group 1, gestational age less than 30 weeks, n = 10; and group 2, gestational age 30-34 weeks, n = 11. The identity of the immunoreactivity as ANP-28 was confirmed by HPLC. Plasma ANP was significantly higher in group 1 than in group 2 on day 2 and day 5 (p < 0.01) and ANP concentration decreased by day 5 in both groups (group 1, p < 0.01; group 2, p < 0.02). The results showed no correlation between plasma ANP concentration and urinary sodium excretion or creatinine clearance, which may be due to a blunted renal response to ANP, but other factors may be involved also. We conclude that preterm infants are able to release large amounts of ANP, but a high plasma ANP concentration does not correlate directly with renal regulation of sodium and water balance.


Participation of immune complexes in adenovirus infection.

To determine the participation of immune complexes during adenovirus infection, we evaluated serum and necropsy specimens of patients with confirmed adenovirus infection of the lower respiratory tract. In lung and kidney from seven dead patients, immunofluorescence revealed the presence of hexon, immunoglobulins and complement. These patients had clinical manifestations of kidney dysfunction. In dead patients (3/3 in whom serum was available) neither anti-adenovirus antibodies nor adenovirus-specific immune complexes could be found in the final stage of the infection. However, two of these patients had anti-adenovirus antibodies and immune complexes in samples obtained early in the infection. Most patients (16/19) who survived the infection had circulating anti-adenovirus antibodies. Half also had immune complexes specific for adenovirus in some moment of the illness. This suggests that immune complexes arise during respiratory infection by adenovirus, probably contributing to its clinical picture.


Role of non-capsulated Haemophilus influenzae as a respiratory pathogen in children.

During a 12-month surveillance period from 1981-1982, non-capsulated Haemophilus influenzae was detected in nasopharyngeal aspirates from 64 (14%) of the 449 children hospitalized for middle or lower respiratory infection. An antibody response to H. influenzae was indicated in 15(23%) of the 64 patients with H. influenzae present in nasopharyngeal aspirate and in 10 (3%) of the 385 patients with a negative finding. Thus, serological evidence of H. influenzae infection was demonstrated in 25 (6%) of all the 449 children with respiratory infection. Of 13 patients with cultures positive for H. influenzae acute otitis media, an antibody response was seen in only 4 (30%) patients. H. influenzae infection was associated with infections caused by other microbes in 20 children (80%), with viral infections in 60% and with pneumococcal infections in 24% of cases. An infection focus was present in 15 (79%) of the 25 patients with H. influenzae infection; pneumonia was present in 10 cases and acute otitis media in 9 cases. Non-specific laboratory evidence of bacterial infection was seen in 11 patients (58%); C-reactive protein was increased in 7 and erythrocyte sedimentation rate in 9 patients. It is concluded that non-capsulated H. influenzae is a genuine respiratory pathogen in children. H. influenzae infections appear to be secondary to preceding viral or other bacterial infections in children who are carriers of this strain.


Role of Moraxella (Branhamella) catarrhalis as a respiratory pathogen in children.

During a 12-month surveillance period in 1981-1982, Moraxella catarrhalis was detected in cultures from nasopharyngeal aspirates from 76 (17%) of 449 children hospitalized with middle or lower respiratory tract infection. Seroconversion to M. catarrhalis was positive in 4 (5%) of the 76 patients with M. catarrhalis present in nasopharyngeal aspirates and in 4 (1%) of 373 patients with a negative finding. Although children with respiratory tract infections were often colonized by the organism, this was rarely the infective agent of the middle or lower airways. Four of 8 patients with seroconversion to M. catarrhalis exhibited a concomitant RSV infection. The carriage of this species was more closely associated with parainfluenza virus infections. Serological responses to M. catarrhalis were not associated with acute otitis media, and were also rare in children with pneumonia. It is concluded that bronchopulmonary infections caused by M. catarrhalis are rare in children, and that M. catarrhalis aetiology need not be considered in the selection of antibiotics in cases of community-acquired pneumonia or other infections of the middle or lower respiratory tract affecting primarily healthy children.


Nested amplification protocol for the detection of Mycobacterium tuberculosis.

Several methods for rapid diagnosis of tuberculosis have been devised through DNA amplification. However, the chemically strong cell wall of the species, the presumptively low numbers of organisms and their uneven distribution in clinical samples, and the lack of a "gold standard" for diagnosing tuberculosis, have hindered the routine clinical use of this method. In a pediatric patient group, these factors are more perplexing. To circumvent these problems, we made use of nested amplification and developed a standard protocol for extracting DNA from various forms of clinical samples which were suitable to our clinical laboratory. It is our impression that the overall sensitivity, including technical bias accompanying this method, is equal to, or at least greater than, that of culture. Most notably, the rapidity in obtaining results and the simplicity in handling, storage and transfer of samples are the principal advantages of this method.


Public health nursing in schools: perceptions of public school administrators.

In localities throughout the country, in lieu of school nurses, nursing services are provided to county schools by public health nurses. The multiple demands placed upon these nurses and counties' fund limitations suggested this study of school administrators' perceptions of nursing responsibility and nursing activities. Administrators of elementary, middle, and high schools were surveyed by questionnaire as to (1) area(s) of nursing responsibility they considered most important and (2) their rank ordering of importance of individual nursing activities. Supervision activities related to communicable disease and immunization garnered the highest ratings. The only significant difference in ranking between groups of administrators was that health counseling for students was ranked higher by high school administrators, whereas health education for parents was ranked higher at the elementary level.


Scabies: update on diagnosis and treatment.

Scabies, a pruritic, contagious skin disease, is endemic in our society. It is especially prevalent in schools and day care centers. Close physical contact, such as that of children playing, is required for transmission. During the past decade a new therapeutic agent has replaced standard therapy. Diagnosis, symptoms, possible complications and treatment options are discussed.


Color-vision deficiency--what does it mean?

Color-vision deficiency is a disorder affecting a significant proportion of the population, yet it remains poorly understood by school personnel as well as the general public. This article examines the many ways abnormal color perception affects peoples' lives. The role of the school nurse in detection of the problem, plus education and counseling of the affected student, parents, and teachers is discussed.


A five year review of anaerobic, necrotizing soft tissue infections: a nursing perspective.

Anaerobic necrotizing soft tissue infections are known for their devastating effects of tissue destruction and death. These infections may occur as a result of trauma, surgical intervention or occur spontaneously in predisposed individuals. They are caused by a wide range of anaerobic organisms and may be categorised according to the tissue involvement as Necrotizing Fasciitis and Myonecrosis. A five year review of patients admitted for hyperbaric oxygen (HBO) therapy and requiring intensive care revealed a patient group numbering 25, roughly equally divided between the two classifications of tissue involvement. Trauma was an aetiological factor in 5 of these cases. Cancer and diabetes mellitus were also prominent aetiological factors. Treatment consisted of the triad of early selective/aggressive surgery, high dose antibiotic therapy and HBO therapy. The mortality of the group was 25%. Delay in treatment was associated with increased mortality. Nursing care, for this particular patient group is demanding, requiring particular attention to wound care, analgesia, transport, psychosocial care of patient with mutilating wounds, nutrition and temperature homeostasis. It is a cause for concern that two cases occurred after elective orthopaedic procedures requiring the application of plaster of paris (POP) cast over a leg.


Creating the optimum environment for pressure area care.

Pressure area care is often thought to be only 'skin deep' but this does not fulfil the philosophy of holistic patient care. Nurses, as the pivot of the multidisciplinary team, must fully assess each patient's needs and implement care based on this assessment, thereby creating the optimum environment for pressure area care.


Episiotomy vs perineal tear: which is less traumatic?

Episiotomy is a well-established procedure in obstetric care worldwide. This article examines the available research and literature on episiotomy vs perineal tear to determine whether there is any evidence that episiotomy is indeed less traumatic than allowing the perineum to tear.


Children in critical care: how parents cope.

This article examines the parental role in the critical care setting. Parents' perceptions of stress and stressors are discussed, and the coping strategies developed by families to deal with them are identified. The implications of the findings are discussed in the light of current practice.


Health visiting an elderly couple.

Health visitors play an important role in their involvement with the elderly population. As Parkinson's disease becomes increasingly prevalent among elderly people, a multidisciplinary approach to treatment and care is essential in the holistic assessment and management of the condition. The importance of the carer in the life of the elderly person with Parkinson's disease cannot be overemphasized. Effective two-way communication and involvement of both the sufferer and main carer in decisions about treatment and care are essential. Effective communication between all members of the primary healthcare team is necessary for continuity of care and support. The use of the Neuman System Model in this case demonstrates the way in which tools of assessment can influence our perception of the client, the type of information obtained and the care and support clients receive.


Creativity in nurse education.

Educationalists have been accused of suppressing, or at least not encouraging, creativity in nursing students. Is this still the case or are the changes in nurse education helping to reverse this trend?


Management of an inadequately ventilated patient.

The aim of this article is to help the nurse aider recognize and manage breathing problems other than those associated with upper airway obstruction. Although the emphasis is on nurse aid in the work environment, inadequate ventilation may have to be dealt with in any nurse-aid situation.


How to be successful when applying for a postregistration course: 1.

The recent publication of the Tomlinson Report (Department of Health, 1992) will see far-reaching changes to the employment prospects for many nurses. Therefore, nurses need to be fully aware of the available opportunities when applying for a course place to ensure a successful outcome.


Healthcare in Kenya: learning from a Third World country.

Kenya's healthcare problems are exacerbated by illiteracy, widespread communities, poor sanitation in some areas, and tribal customs and traditions. This article gives an overview of Kenya's healthcare system that was gained by the author during a study tour to Kenya in March 1991.


Reaction of the human gingival tissue to different suture materials used in periodontal surgery.

The gingival reaction to 4 different suture materials used in periodontal surgery was studied in 36 patients. The gingiva was sutured prior to surgery and biopsies were taken at 3, 7 and 14 days to observe the tissue reaction. The histological examination showed that silk caused the most intense and longest inflammatory response. Polyester and perlon provoked shorter, less intense tissue reactions than silk, and nylon caused the least inflammatory response, with earlier tissue repair.


Influence of age on the reactivity of the BANA test among Brazilian children.

Three hundred and twenty samples of subgingival plaque were obtained from 80 caucasian girls, ranging from 10 to 13 years of age. The samples were analyzed to verify the influence of age upon colonization of the gingival sulcus by microorganisms potentially pathogenic to the periodontal tissues. The gingival and plaque status were evaluated through the gingival index (GI) and plaque index (PlI) and the microflora was assessed by the enzymatic method benzoyl-arginine-naphthylamide (BANA). The results of the BANA test were positive for 62.50% of the tested individuals and 40% of the examined sites. The influence of age was statistically significant on BANA reactivity, and the number of positive sites was greater at 11 (57.5%) than at 12 years (28.8%).


Surface tension of several drugs used in endodontics.

Surface tension of various drugs used in endodontic therapy was studied by the capillary method. Drugs of the phenol group--eugenol, paramonochlorophenol, tricresol-formalin and phenol--presented very low surface tension. The association of a detergent to the solution of calcium hydroxide reduced its surface tension by half.


Dental pain and sleep. Experimental study on guinea pigs (Cavia porcellus).

The relationship between pain and sleep was studied by using electrocorticograms (ECoG) taken from guinea pigs submitted to noxious stimulation (NS) of the dental pulp of the upper incisors, after local application of serotonin (5-HT) to the obex (a brain region inductive to sleep). The results showed that the dental electrical stimulation of the sleepy animal was capable of keeping this animal in a state of vigilance and excitation, suggesting that the trigeminal system probably acts on the sleep regulating centers.


Effect of polishing burs and stones on the micro-hardness of dental amalgam.

Square standard cavities were prepared in human teeth and restored with amalgam obtained from alloys of different trade-marks. Twenty-four hours after condensation, excess amalgam was removed from three of the four margins, each with a different rotatory instrument (number 4 bur, multiblade finishing bur, and fine green stone). No rotatory instrument was used on the fourth margin (control), and this control was polished with pumice and zinc-oxide pastes and Sweeney's brushes. Vickers' tests for micro-hardness of the amalgam were performed on the four margins of the restorations. The restorations were then submitted to metallographic polishing, and a second micro-hardness measurement was made seven days later. The statistical analysis of the data showed that micro-hardness values were higher at the margins on which no rotatory instruments were used. The lowest micro-hardness values were found at the margins where finishing and/or round burs were used. Polishing with fine green stones gave intermediate values.


Root form and canal anatomy of maxillary first premolars.

The external and internal anatomy of 240 extracted, maxillary first premolars was studied. The external anatomy was studied by measuring each tooth and by observing the direction of the root curvatures from the facial and proximal aspects. The internal anatomy of the pulp cavity was studied by a method of making the teeth translucent. A total of 55.8% of the teeth had a single root, 41.7% had two roots and 2.5% had three roots. Considering all of the first premolars, 17.1% had one canal, 80.4% had two canals and 2.5% had three canals.


A method to evaluate and compare roentgenograms.

A simple and practical method is suggested to evaluate and compare roentgenograms concerning optical density and contrast. The method is specifically indicated for research in which a metallic stepwedge penetrometer and a photodensitometer are used. A PC computer may be optionally employed for the mathematical and statistical processing of the data.


Effects of baroceptor and cardiopulmonary reflexes on neural control of heart rate in normal man, as assessed by power spectral analysis.

This study was designed to establish the neurally-mediated effects of baroceptor and cardiopulmonary reflexes on heart rate in normal subjects. We therefore studied the effects of various interventions, able to modify the activity of arterial baroreceptors and cardiopulmonary receptors, on the power spectrum of the R-R interval in nine healthy men. To confirm the efficacy of these interventions left ventricular volume was monitored using a portable radionuclide probe. Isosorbide dinitrate (5 mgm sublingually) while sitting unloads both baroreceptors and the cardiopulmonary receptors; it decreased left ventricular end-diastolic volume (p < 0.01) and the mean R-R interval (p < 0.005), increased the power of the low-frequency (LF) component of the R-R interval (p < 0.01), decreased the power of the high-frequency (HF) component (p < 0.005) and increased the LF/HF ratio (p < 0.05). The application of cuffs around the thighs in the supine position, which unloads only cardiopulmonary receptors, decreased left ventricular end-diastolic volume (p < 0.05) but did not affect mean R-R interval, LF component, HF component and LF/HF ratio (p > or = 0.10). Leg raising, which loads only cardiopulmonary receptors, increased left ventricular end-diastolic volume (p < 0.05) and did not affect the mean R-R interval, LF component, HF component and LF/HF ratio (p > or = 0.10). In conclusion, our data suggest that, in normal man, baroreceptor unloading increased sympathetic and decreased parasympathetic neural control of heart rate; cardiopulmonary reflexes do not appear to have a direct neurally mediated effect on heart rate.


A comparison of the effects of the selective peripheral alpha 1-blocker terazosin with the selective beta 1-blocker atenolol on blood pressure, exercise performance and the lipid profile in mild-to-moderate essential hypertension.

The effects of six weeks of treatment with the selective peripheral alpha 1-adrenoceptor blocker terazosin, or the selective beta 1-adrenoceptor blocker atenolol on blood pressure, exercise performance and blood lipid profile were compared in a single-blind, randomized, crossover study of 17 patients with mild-to-moderate essential hypertension. Although both drugs significantly reduced blood pressure at rest, atenolol caused a larger fall in supine blood pressure (11/11 and 7.5/7.0 mmHg, atenolol and terazosin, respectively; p < 0.001). Both treatments controlled the pressor response to exercise, although a greater reduction in diastolic blood pressure was observed at the end of exercise on terazosin (74.0 +/- 5.7 and 91.6 +/- 4.0 mmHg, terazosin and atenolol, respectively; p < 0.01). Alpha 1-blocker therapy was not associated with any measurable improvement or deterioration in cardiopulmonary performance and exercise duration. Unlike atenolol, terazosin therapy had the potentially beneficial effect of reducing serum total cholesterol levels and increasing the high-density lipoprotein-cholesterol/low-density lipoprotein-cholesterol ratio.


Heart rate variability in smokers, sedentary and aerobically fit individuals.

To test the hypothesis that certain lifestyles may affect cardiovascular regulatory mechanisms, heart rate variability (HRV) among three age-matched groups with different lifestyles (smoking, sedentary and aerobically fit) were compared. Heart rate variability was defined as the difference in heart rate during inhalation vs. exhalation. Heart rate was obtained from normal RR intervals, using a continuous electrocardiogram recording, while subjects were seated and breathing at an augmented tidal volume, and also while subjects were standing and breathing at normal tidal volumes. In the physically active group, heart rate variability was significantly elevated at rest as well as during some of the autonomic tests, when compared to the sedentary and smoker groups (p < 0.05). A hypothesis to explain this finding is that smoking or a sedentary lifestyle reduces vagal tone, whereas a physically active lifestyle, resulting in enhanced aerobic fitness, increases vagal tone. These findings may have cardiovascular health implications.


Sympathoinhibition and hypotension in carotid sinus hypersensitivity.

Carotid sinus reflex hypersensitivity is a known cause of syncope in humans. The condition is characterized by cardioinhibition and vasodepression, each to varying degrees. The extent and importance of sympathoinhibition has not been determined in patients with carotid sinus hypersensitivity. This study reports on the extent of sympathoinhibition measured directly directly during carotid massage with and without atrioventricular sequential pacing, in a patient with symptomatic carotid sinus reflex hypersensitivity. Carotid massage elicited asystole, hypotension and complete inhibition of muscle sympathetic nerve activity. Carotid massage during atrioventricular pacing produced similar sympathoinhibition, but with minimal hypotension. Therefore, sympathoinhibition did not contribute importantly to the hypotension during carotid massage in the supine position in this patient. Further investigations are required to elucidate the relation of sympathoinhibition to hypotension in patients with carotid sinus hypersensitivity in the upright position.


Influence of posture on cardiorespiratory reflexes in normal subjects and patients with diabetes mellitus.

This study was designed to assess the effect of patient posture, either sitting or supine, on the results and diagnostic yield of tests of cardiorespiratory reflexes on 25 normal subject controls and 128 patients with diabetes mellitus. The heart rate changes during slow breathing at 6 per minute (delta R6) and during a Valsalva manoeuvre (highest heart rate during manoeuvre divided by lowest heart rate within 30 s after manoeuvre; Valsalva ratio) were measured from the electrocardiographic signal and tachometry. In control subjects, heart rate changes during slow breathing averaged 25.0 when sitting and 21.3 when supine (p < 0.01); Valsalva ratio averaged 1.90 and 1.83 (p > 0.2) respectively. In diabetic patients, mean values for heart rate changes during slow breathing were 6.1 and 5.1, and mean values for Valsalva ratio were 1.23 and 1.28 in sitting and supine postures respectively. According to our normal limits, heart rate changes during slow breathing was below normal in 109 patients tested when sitting and in 113 tested when supine, and Valsalva ratio was abnormal in 103 and 95 respectively. These results indicate that subject posture is an important variable of cardio-respiratory reflex testing, and should be standardized to allow comparisons of individual results.


Tachyphylaxis to capsaicin-induced cough and its reversal by indomethacin, in patients with the sinobronchial syndrome.

Cough reflex testing with capsaicin has been used to study the pathophysiology of the cough reflex and the antitussive effects of various drugs. Although the reproducibility of capsaicin-induced cough has been well established in normal subjects, it is not known if prior challenge with capsaicin reduces the subsequent cough response to inhaled capsaicin in patients with the sinobronchial syndrome, a condition characterized by chronic upper and lower airway inflammation. Measurement of the capsaicin cough threshold, defined as the lowest concentration of capsaicin eliciting five or more coughs, was repeated four times at intervals of 15, 30 and 60 min in eleven patients with the SBS and ten normal subjects. The cough thresholds at 15, 30 and 60 min were greater than the initial value in patients with the SBS but not in normal subjects. In addition, we examined the effect of 4 days treatment with indomethacin (100 mg/day) on the cough thresholds measured twice at an interval of 15 min in eight patients with the SBS. Indomethacin increased the initial cough threshold and reduced the increment in the post-15 min cough threshold from the initial value compared with placebo, thus reducing the tachyphylaxis. These results indicate that chronic airway inflammation may be responsible for the decreased response (tachyphylaxis) to repeated inhalation of capsaicin, and suggest that cyclooxygenase products released by the airway inflammation may be involved in tachyphylaxis, cough receptor sensitivity to inhaled capsaicin, or both, in patients with the SBS.


Autonomic neuropathy and immunological abnormalities in Chagas' disease.

Chagas' disease (American Trypanosomiasis) is caused by infection with the haemoflagellate parasite Trypanosoma cruzi, which is transmitted from animals to man by the Reduviidae bug. The human disease is characterized by two phases. In the first (acute phase) parasitaemia is high and general symptoms variable. The next, which is lifelong (chronic phase), is characterized by inflammatory lesions in cardiac and skeletal muscle, gastrointestinal, the autonomic nervous system. Parasites are difficult to detect in blood and affected tissues. Lesions within the autonomic nervous system, lead to development of cardiomyopathy, megaoesophagus and megacolon. The discrepancy between the profusion of inflammatory lesions and the absence of parasites suggests the development of autoimmunity probably of a cell-mediated type. Several autoimmune abnormalities have been noted during Trypanosoma cruzi infection. These include suppression of the specific response to autoantibodies directed against antigens located in the endocardium and in nerves, and development of cell-mediated immunity against host antigens (cytotoxic T- and delayed type hypersensitivity T-cells). These autoimmune disorders are thought to be responsible for much of the pathological damage in chronic Chagas' disease.


What are enzyme structures telling us?

Most globular proteins are waxy inside and soapy outside. Their compact structures are stabilised by the hydrophobic effect which is mainly entropic, and by hydrogen bonds and dispersion forces which are mainly enthalpic. Structurally homologous proteins tend to share a common set of internal sites from which polar residues are excluded, even if they share little sequence homology. Electrostatic effects are dominant in enzyme catalysis. The active sites of enzymes are generally buried in clefts or cavities where dipoles tend to be oriented so as to optimise the pKas of ionizable amino acid side chains for catalysis; substrates are clamped close by to maximise electrostatic interactions. The activities of many enzymes have long been known to be controlled by allosteric effects or by induced fit. Some serine proteinase inhibitors have evolved yet another control mechanism: this is a spring-loaded safety catch that makes them revert to their latent, stable, inactive form unless the catch is kept in the 'loaded' position by another molecule.


Substrate recognition by proteinases.

The molecular recognition of limited proteolytic site substrates by serine proteinases has been compared and contrasted to the recognition of serine proteinase inhibitors, utilising the coordinate sets contained in the Brookhaven Protein Databank. Most families of these inhibitors are known to possess a structurally conserved recognition motif at their reactive site-binding loops. Structural comparisons with trypsin limited proteolytic sites revealed that the in situ conformation of these substrates bears little resemblance to the inhibitor-binding loops. Assuming that both inhibitors and substrates bind to the proteinase in the same manner, segmental mobility would be required to permit substrates to adopt an 'inhibitor-like' binding conformation, which is presumed to be necessary for proteolysis. Modelling experiments have been conducted to attempt to introduce such a conformation into tryptic limited proteolytic segments of the native proteins, to test the ability of the limited proteolytic sites to alter their geometry. Further to this, the conformational parameters of accessibility, protrusion, mobility and secondary structure have been analysed and incorporated into a predictive algorithm to assign likely limited proteolytic sites within native protein structures.


Catalytic mechanism of glycogen phosphorylase.

Proposals for the catalytic mechanism of glycogen phosphorylase based on crystallographic studies with the T-state form of the enzyme are reviewed in the light of new structural data from studies with the R-state enzyme. The observed position for a sulfate ion at the catalytic site and the crystallographic binding studies of glucose-1-P to the R-state enzyme support the previous proposals in which the 5'-phosphate group of the essential cofactor pyridoxal phosphate functions as an acid-base to promote attack by the substrate phosphate on the polysaccharide substrate. The sulfate (phosphate) recognition site, which is fully formed only in the R state, comprises interactions from the side chains of Arg-569 and Lys-574 and the main chain nitrogen of Gly-135 at the start of an alpha-helix. The interactions of the cofactor 5'-phosphate do not change between the T and the R state. Other groups on the protein play important roles in binding the substrate but are not involved in the catalytic reaction. The presumed reactive conformation of bound substrate has been observed with heptulose-2-P in the T state and in this conformation stereoelectronic arguments suggest the C(1)-O(1) bond is weakened. For the natural substrate glucose-1-P it is proposed that the reactive conformation is achieved only in the presence of the oligosaccharide component in the reactive ternary enzyme-substrate complex. The phosphate recognition sites are discussed.


cAMP-dependent protein kinase and the protein kinase family.

The structure of the catalytic subunit of cAMP-dependent protein kinase, the first protein kinase structure to be solved, is reviewed. The general architecture of the enzyme is described as well as the active site regions associated with substrate binding and catalysis. In particular, the unique features of the protein kinase nucleotide fold are outlined. While the catalytic subunit is one of the simplest of the protein kinases, it nevertheless serves as a structural framework for the catalytic core of the entire protein kinase family which now includes over 200 important regulatory enzymes. The essential and conserved features of this core are summarized, and a preliminary model of myosin light-chain kinase, based on the structure of the catalytic subunit, is also discussed.


Mechanism of allosteric transition of bacterial L-lactate dehydrogenase.

The allosteric behaviour of L-lactate dehydrogenase (L-lactate:NAD+oxidoreductase, EC 1.1.1.27, LDH) from Bifidobacterium longum aM101-2 was studied by means of the subunit hybridization technique as well as X-ray crystallography. Homotropic allosteric response of the LDH activity was found against the concentration of its substrate, pyruvate. Heterotropic allosteric activation of the enzyme was induced by the addition of fructose 1,6-bisphosphate (FBP). Two mutant enzymes, which had either altered sensitivity to FBP or altered substrate specificity from pyruvate to oxaloacetate, were made by site-directed mutagenesis. Hybrid LDHs, between the wild and the mutant LDHs, were made by in vivo subunit hybridization using double transformation of Escherichia coli with two plasmids carrying either the gene of wild or mutant LDH. Introduction of only one desensitized mutant subunit to the LDH changed the characteristic of the wild enzyme to that of the mutant LDH. Kinetic studies on hybrid enzymes consisting of subunits having different substrate specificity indicated that there was a strong cooperative interaction among subunits. These results strongly support the idea that the allosteric change of the LDH fits the concerted-symmetry model proposed by Monod, Wyman, and Changeux. We analysed the crystallographic structure of the LDH having low affinity to substrate at 1.9 A resolution. By the comparison of the structure with that of other LDHs, we concluded that the conformational transition of the LDH was mainly caused by concerted rotations of subunits.


Dissection of protein structure and folding by directed mutagenesis.

The lysozyme from bacteriophage T4 is being used as a model system to determine the roles of individual amino acids in the folding and stability of a typical globular protein. One general finding is that the protein is very adaptable, being able to accommodate many potentially destabilizing replacements. In order to determine the importance of 'alpha-helix propensity' in protein stability, different replacements have been made within alpha-helical segments of T4 lysozyme. Several such substitutions of the form Xaa-->Ala increase the stability of the protein, supporting the idea that alanine is a strongly helix-favouring amino acid. It is possible to engineer a protein that has up to ten alanines in succession, yet still folds and has normal activity. This illustrates the redundancy that is present in the amino acid sequence. A number of 'cavity-creating' mutants of the form Leu-->Ala have been constructed to understand better the nature of hydrophobic stabilization. The structural consequences of these mutations differ from site to site. In some cases the protein structure hardly changes at all; in other cases removal of the wild-type side-chain allows surrounding atoms to move in and occupy the vacated space, although a cavity always remains. The destabilization of the protein associated with these cavity-creating mutations also varies from case to case. The results suggest how to reconcile recent conflicting reports concerning the strength of the hydrophobic effect in proteins.


Pathway of protein folding.

The order of formation of substructures in the folding of barnase has been determined by a protein engineering procedure and corroborated and complemented by NMR experiments. Early events are the formation of the centre of the beta-sheet and the C-terminus of the major alpha-helix. These later dock to form the major hydrophobic core. Structural studies of fragments of barnase in solution show that a peptide that spans the major alpha-helix is found to contain a significant fraction of its C-terminal region in the helical structures. The formation of the native secondary structure as an early event in folding and in isolated fragments is accompanied by considerable burial of hydrophobic surfaces. The experimental data support a model for protein folding in which initiation sites in secondary structure are driven by local hydrophobic interactions, and their docking via further hydrophobic interactions drives the formation of tertiary structure.


Exploring the molecular mechanism of dihydrofolate reductase.

A description of the transition-state complex of the enzyme dihydrofolate reductase is presented based upon extensive crystallographic studies of substrate/cofactor complexes from various sources. Structural elements of DHFR have been identified which contribute in different ways to effect the chemical step involving protonation and hydride transfer. Emphasis is placed upon residues, structures and solvent which create the appropriate environment for stabilization of the positively charged carbenium ions which are thought to be developed in the transition state of the enzyme-catalysed reaction. Changes in the positions of the substrate and cofactor in the active site which must occur to achieve the correct geometry for hydride transfer are also described. Finally, the structures of several site-directed mutants of DHFR are presented and the results are discussed in the context of the proposed structure for the transition state.


Simulation analysis of triose phosphate isomerase: conformational transition and catalysis.

A theoretical approach is employed to study the catalysis of the dihydroxyacetone phosphate (DHAP) to D-glyceraldehyde 3-phosphate (GAP) reaction by the enzyme triose phosphate isomerase (TIM). The conformational change in a loop involved in protecting the active site from solvent is examined by use of X-ray data and molecular dynamics simulations. A mixed quantum-mechanics and molecular mechanics potential is used to determine the energy surface along the reaction path. The calculations address the role of the enzyme in lowering the barrier to reaction and provide a decomposition into specific residue contributions. To obtain a clearer understanding of the electronic effects, the polarization of the substrate carbonyl group by the active site residues is examined and compared with FTIR measurements on the wild-type and mutant forms of the enzyme.


Cold destabilisation of enzymes.

The thermal stability profile of chymotrypsinogen has been investigated in the temperature range 230-340 K, with special emphasis on the phenomenon of cold instability. Differential scanning calorimetry was used to study the heat capacities of the native and denatured protein in undercooled solution and the results were combined with those obtained by spectrophotometry at ordinary temperatures. The partial heat capacities of both forms decrease with decreasing temperature, assuming negative values. In the experimentally accessible temperature range (above the spontaneous nucleation temperature of ice) the heat capacity difference delta C is found to be positive with a non-linear temperature dependence. delta C is predicted to change sign at some low temperature which cannot, however, be reached by experiment for chymotrypsinogen. In contrast to earlier studies, covering a much more limited temperature range and having to employ an additional destabilisation by means of pH and/or chaotropes, the present findings permit the construction of a more reliable thermodynamic stability profile and related properties. These differ in important details from those reported for other proteins, but based on measurements only in the neighbourhood of the heat-denaturation temperature. The thermodynamic characteristics are, however, in good agreement with earlier predictions and with recent low-temperature measurements on the tetrameric enzyme lactate dehydrogenase.


Three-dimensional profiles for analysing protein sequence-structure relationships.

In the method of 3D (three-dimensional) profiles, each residue position in a protein is characterized by its environment and is represented by a row of 20 numbers in a table, the profile. These numbers are the statistical preferences (called 3D-1D scores) of each of the 20 amino acids for this environment. A profile is computed from the coordinates of a protein model, and it gives a score S for any amino acid sequence folded as the model. To date 3D profiles have found three applications. The first is to identify other protein sequences which are folded in the same general pattern as the structure from which the profile was prepared. These are sequences which have high scores for the profile computed from the model. The second is to assess the validity of protein models, however determined. Correct models are found to give profiles that have high scores for their own amino acid sequences, and incorrect models are found to have lower scores. The example of the X-ray structure determination of diphtheria toxin is discussed. The third application is to assess which is the stable oligomeric state of a folded protein. Several examples suggest that the highest profile score for a sequence is achieved when the protein is aggregated into its most stable oligomeric state.


Vibrational Raman optical activity of enzymes.

Advances in Raman optical activity (ROA) instrumentation, based on the employment of a backscattering geometry together with a back-thinned CCD detector and a single-grating spectrograph with a holographic edge filter, have now enhanced the sensitivity to the level necessary to provide vibrational ROA spectra of proteins in aqueous solution. Early results show at least four separate regions in protein ROA spectra associated with vibrations of the backbone which appear to characterize the alpha-helix, beta-sheet, reverse turn and random-coil secondary conformation content. Side-group ROA features also appear, with tryptophan particularly prominent in lysozyme and alpha-lactalbumin. ROA should become a sensitive new probe of protein folding and ligand-induced conformational change in aqueous solution.


Modelling the structure and function of enzymes by machine learning.

A machine learning program, GOLEM, has been applied to two problems: (1) the prediction of protein secondary structure from sequence and (2) modelling a quantitative structure-activity relationship in drug design. GOLEM takes as input observations and combines them with background knowledge of chemistry to yield rules expressed as stereochemical principles for prediction. The secondary structure prediction was explored on the alpha/alpha class of proteins; on an unrelated test set it yielded 81% accuracy. The rules from GOLEM defined patterns of residues forming alpha-helices. The system studied for drug design was the activities of trimethoprim analogues binding to E. coli dihydrofolate reductase. The GOLEM rules were a better model than standard regression approaches. More importantly, these rules described the chemical properties of the enzyme-binding site that were in broad agreement with the crystallographic structure.


Functional zinc-binding motifs in enzymes and DNA-binding proteins.

Zinc is now known to be an integral component of a large number and variety of enzymes and proteins involved in virtually all aspects of metabolism, thus accounting for the fact that this element is essential for growth and development. The chemistry of zinc, superficially bland, in reality has turned out to be ideally appropriate and versatile for the unexpected development of multiple and unique chemical structures which biology has used for specific life processes. The present discussion will centre on those distinctive zinc-binding motifs that are critical both to enzyme function and the expression of the genetic message. X-Ray diffraction structure determination of 15 zinc enzymes belonging to IUB classes I-IV provide absolute standards of reference for the identity and nature of zinc ligands in their families. Three types of zinc enzyme binding motifs emerge through analysis of these: catalytic, coactive or cocatalytic, and structural. In contrast to zinc enzymes virtually all DNA-binding proteins contain multiple zinc atoms. With the availability of NMR and X-ray structure analyses three distinct motifs now emerge for those: zinc fingers, twists and clusters.


Structure and mechanism of D-xylose isomerase.

The action of xylose isomerase depends on the presence of two divalent cations. Crystal structure analyses of the free enzyme, and of the enzyme bound to a variety of substrates and inhibitors, have provided models for a number of distinct intermediates along the reaction pathway. These models, in turn, have suggested detailed mechanisms for the various chemical steps of the reaction: a ring opening catalysed by an activated histidine, a hydride-shift isomerization, and a ring closure which may be facilitated by a polarised water molecule.


Three-dimensional structure of galactose oxidase: an enzyme with a built-in secondary cofactor.

Galactose oxidase is a copper-containing enzyme, which catalyses stereospecific oxidation of primary alcohols. The three-dimensional structure of the enzyme has been determined in this study by X-ray crystallography at high resolution. The molecule is almost entirely composed of beta-structures and consists of three domains. The arrangement of 28 beta-strands in the second domain is of particular interest, having seven four-stranded antiparallel beta-sheets with pseudo-sevenfold symmetry. The copper site has square-pyramidal coordination with two histidines, one tyrosine and one exogenous ligand at the equatorial sites and another tyrosine at the axial site. The most intriguing structural feature is a covalent bond between C epsilon 1 of Tyr-272, which is one of the equatorial ligands, and S gamma of Cys-228. This unexpected thioether bond, and Trp-290 stacked above it, strongly supports the presence of a tyrosine free radical in the enzyme as a 'built-in' secondary cofactor. Calculation of the molecular surface shows a small pocket at the copper site and suggests a substrate-binding model, which can explain the substrate specificity. A model for the catalytic mechanism, involving a tyrosine free radical and basic tryptophan, is also proposed.


Induced-fit movements in adenylate kinases.

Adenylate kinases have an M(r) around 23,000 which classifies them among the smallest phosphoryl group transferring enzymes. In order to prevent phosphoryl transfer to water, i.e. hydrolysis, these enzymes undergo induced-fit motions on substrate binding and assemble/disassemble their catalytic centres during each reaction cycle. Details of these processes have been derived from several X-ray structure analyses. The disturbance of these analyses by crystal-packing effects is discussed.


Structural and evolutionary relationships in lipase mechanism and activation.

Lipases that break down triglycerides to monoglycerides and glycerol are characterised by low or no activity in water; in the presence of an oil/water interface, however, their activity increases markedly. The structural and chemical basis for this phenomenon, referred to as interfacial activation, has been revealed by the crystal structures of a fungal lipase and a human pancreatic lipase which evidently have a divergent evolutionary history. These studies reveal that: (1) In both enzymes the catalytic sidechains are Asp:His:Ser, the same as occur in the serine proteases. The active atoms on this catalytic triad have essentially identical stereochemistry in the serine proteases and in these two lipases. The amino acids themselves, however, have quite different conformations and orientations. (2) In both enzymes the catalytic groups are buried and inaccessible to the surrounding solvent. Burial in these two lipases is brought about by a small stretch of helix (the lid) which sits over the active site. (3) In both enzymes this helical lid presents non-polar sidechains over the catalytic group, and polar sidechains to the enzyme surface. Although the 'lids' are very similar in construction in the two enzymes, they belong to very different parts of the polypeptide chain. (4) Although the amino acid sequences have no identity (except at the active serine) the two enzymes show a similar architectural framework consisting of a central five-stranded parallel beta sheet structure. The catalytic groups decorate this beta sheet structure in a strikingly similar way though there are also some significant differences. The crystal structure of the complex between the fungal enzyme and a substrate analogue demonstrates how the helical lid is displaced to reveal the active site. The movement of the lid also greatly enlarges the non-polar surface at the active surfaces and buries previously exposed polar residues. The movement of the lid also helps to create the appropriate movement at the oxyanion hole. It is possible to define the stereochemistry at the active site and to identify the positioning of the fatty acid and the glycerol moieties.


Role of platelet derived growth factor in bone cell function.

PDGF is a mitogen for cells of the osteoblastic lineage. PDGF is present in the systemic circulation and is locally synthesized by skeletal cells. The systemic form primarily contains PDGF B chains, which are intrinsically more active than PDGF A subunits, the forms secreted by normal bone cells. PDGF AA is regulated by other growth factors and cytokines, which modulate its binding to osteoblastic receptors and its synthesis by skeletal cells. The exact role of PDGF in bone remodelling is still uncertain and current information suggests that this factor has a function in the response to inflammation and wound healing.


The influence of age, size, pubertal status and renal factors on urinary growth hormone excretion in normal children and adolescents.

Overnight urinary growth hormone (GH) excretion was measured in 528 schoolchildren (aged 4-16 years) whose heights and weights were between the third and 97th centiles. Urinary GH increased significantly with age, reaching a maximum in boys at 15-years-old and in girls at 13-years-old. Peak levels were five and three times higher in boys and girls respectively than in 4-year-olds. Maximum urinary GH excretion was seen at breast stages 3 and 4 in girls and at genital stage 4 in boys followed by a decline in both sexes at stage 5. Boys excreted more GH than girls during prepubertal and pubertal years. During prepubertal years there were fluctuations of urinary excretion of GH with age. Height, weight and pubertal status predicted 31% of the variability of urinary excretion of GH, and urinary excretion of creatinine, albumin and N-acetylglucosaminidase (NAG) predicted 52% of the variability. The importance of establishing sound age and sex-related reference ranges for urinary growth hormone is stressed before application of this test to children with growth disorders.


Tissue specific responses to clenbuterol; temporal changes in protein metabolism of striated muscle and visceral tissues from rats.

The beta-adrenoceptor agonist, clenbuterol, was administered orally to male weanling rats for a period of up to 10 days. The composition and fractional rate of protein synthesis (Ks) in skeletal and cardiac muscle, gut and liver were determined. There were few changes in the visceral tissues, but there was marked protein accretion in the muscles. The results suggested that in skeletal muscles there is an increase in both Ks and the amount of protein synthesised per unit RNA. In cardiac muscle, the results indicated that there was only a very transient increase in Ks and that changes in translational capacity (RNA/prot) may account in part for the increase in protein content. It is concluded that the mechanistic basis for the increased protein gain may be different between skeletal and cardiac muscles.


Evolution of the growth hormone-releasing factor (GRF) family of peptides.

1. The primordial GRF may have arisen quite early in evolutionary history, at or prior to (i.e. should immunoreactivity data be confirmed in invertebrates) the appearance of jawed vertebrates (Gnathostomates). A common evolutionary pathway using gene duplication may have been utilized to generate the GRF super-family of peptides. As most members of this peptide superfamily are produced in the gastrointestinal tract, the question is posed whether the GRF may have similar origins. 2. It is suggested that the GRF superfamily has two major branches: a) GRF; PRP/PACAP; VIP/PHI; secretin and b) Glucagon/GLP-1/GLP-2. GIP is likely to be a member of the glucagon branch. The two branches may be attributable to gene duplication encoding an ancestral molecule. These gene duplications are likely to have occurred prior to the evolution of vertebrates (conservatively 400-500 million years ago, and possibly 1 billion years ago). It is probable that peptides homologous to GRF, VIP and glucagon will be isolated from invertebrates. These invertebrate sequences will shed further light upon the evolution of this peptide superfamily. 3. Throughout the GRF superfamily, amphiphilic alpha-helical secondary structures represent preferred bioactive conformations. It is assumed that stable, ordered secondary structures conferring enhanced ligand-receptor interactions were conserved due to selective pressures. 4. It is well documented that hypothalamic GRF stimulates adenohypophyseal GH secretion in a variety of species. Thus far, the physiological effects of GRF have been attributed thus to the elevation of GH, and possibly also IGF-I. Recent data suggests a more liberal view; that GRF may also have direct actions in fetal/placental development, reproduction and immune function. Furthermore these direct effects may be mediated via GRF from either hypothalamic or extrahypothalamic (e.g. placenta, testes, ovary, leukocyte) sources. In conclusion, a great wealth of information has accumulated since the discovery of GRF. Examination of the GRF peptide superfamily from an evolutionary perspective has revealed new insights into the synthesis, processing, degradation, conformation and activities of these molecules. Knowledge obtained from these evolutionary comparisons has also become particularly useful in contemporary peptide drug design, which may be liberally viewed as a form of 'artificial evolution' (i.e. the selective pressure being clinical/veterinary requirements for more potent, long-acting GRF analogs).


The present status in all-trans retinoic acid (ATRA) treatment for acute promyelocytic leukemia patients: further understanding and comprehensive strategy are required in the future.

All-trans retinoic acid (ATRA) has recently been recognized as the first line therapeutic agent in the treatment of patients with acute promyelocytic leukemia (APL). The extraordinary high remission rate achieved by ATRA in comparison with other chemotherapeutic agents suggested that ATRA differentiation induction therapy seemed superior to conventional chemotherapy for APL patients. However, after the great excitement aroused after the initial successes, we have to take stock and examine in detail several problems which have emerged preventing us from improving the clinical outcome in APL. Maintenance in order to prolong remission and prevention of or retreatment for the relapse are the major subjects of concern at present. Efforts should be made either to keep ATRA effective for APL patients or to resensitize the relapsing patients for repeated ATRA therapy. The administration of ATRA should be carefully adapted in accordance with the individual patient's condition. From both conceptual and practical points of view, ATRA differentiation therapy should be combined with chemotherapy, bone marrow transplantation and biomodifier treatment. Thus, a more comprehensive strategy must be planned and developed in the near future. Using molecular biological techniques, the diagnosis of APL can be more precisely made and the course of the disease more closely monitored. The central dogma, still to be revealed, is the relationship between APL pathogenesis, the chromosome translocation present with the relevant molecular alterations and the response to ATRA treatment. Current studies in all these above fields have provided us with a deeper understanding of the pathogenesis of APL and the physiological function and curative action of ATRA.(ABSTRACT TRUNCATED AT 250 WORDS)


The therapeutic potential of interleukin-1 and tumor necrosis factor on hematopoietic stem cells.

Dose intensity is emerging as a crucial determinant of success in cytotoxic cancer therapy; however, myelosuppression presents as one of the major complications encountered with increased dose intensity. Therefore, investigators are looking at the use of cytokine administration in combination with cytotoxic therapy to overcome this problem. Interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) have been shown to be beneficial in protecting the hematopoietic system from radiation and chemotherapy. In this report, we give an overview of studies using IL-1 and TNF-alpha as protective agents and discuss possible mechanisms involved in their protective action. Mice pretreated with IL-1 and/or TNF-alpha were shown to be protected from the lethal effects of radiation and it has been suggested that the mechanism for this protection may be through the production of the antioxidant enzyme manganese superoxide dismutase. Similarly, aldehyde dehydrogenase, an enzyme important in the metabolic pathway of cyclophosphamide compounds, has been implicated as being important in the protection of hematopoietic cells from 4-hydroperoxycyclophosphamide. While IL-1 and TNF-alpha stimulate both of these enzymes, other mechanisms are probably also operative for other forms of chemotherapy, i.e. IL-1 and TNF-alpha were shown to protect hematopoietic progenitors from phenylketophosphamide, a cyclophosphamide derivative that is not metabolized by the enzyme aldehyde dehydrogenase. Furthermore, malignant as well as normal cells may possess receptors for these cytokines; therefore, IL-1 and TNF-alpha will have to be selective in their protection. They must be capable of protecting normal hematopoietic cells while rendering malignant cells susceptible to the toxic actions of the chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)


Platelet storage pool deficiency, leukemia, and myelodysplastic syndromes.

Abnormalities in platelet dense granules, small intracellular organelles containing ATP, ADP, calcium, serotonin, and pyrophosphate, have frequently been reported in patients with leukemia and myeloproliferative disorders, particularly acute and chronic myelogenous leukemia. Recent studies of a family which includes several members with an autosomal dominant dense granule deficiency condition show an association between the presence of this form of dense granule deficiency and the development of acute myelogenous leukemia. Studies in two additional patients, one with the Monosomy 7 syndrome and the second with a myelodysplastic syndrome, revealed a defect in platelet dense granules. This defect appears to be due to an abnormality in the formation of these granules rather than the presence of empty vesicular structures or decreased contents due to activation associated secretion. The results suggest that the defect in platelet dense granules associated with leukemia or myelodysplastic syndromes may result from a chromosome alteration in the megakaryocyte cell line leading to decreased formation of dense granules. Studies in the family with an inherited bleeding disorder suggest that a gene coding for a protein important for the formation of dense granules is located adjacent to a gene which, when abnormal, may predispose to the development of leukemia.


Acute tumor lysis syndrome in hematologic malignancies.

Acute tumor lysis syndrome (ATLS) represents one of the most urgent of all oncologic treatment related complications. This is due not only to its broad impact on organ dysfunction, but also to its relative ease of prevention and treatment when aware of its potential threat. Despite anecdotal experiences of ATLS in settings outside the use of chemotherapy, the majority of patients susceptible to ATLS can be predicted using clinical as well as laboratory parameters and prophylaxis can prevent this potentially lethal consequence of otherwise successful cancer therapeutics. This review article will attempt to bring the critical aspects involving ATLS together in order to delineate the pathophysiology as well as treatment of this generally avoidable entity.


The use of fluconazole prophylaxis in patients with chemotherapy-induced neutropenia.

Systemic Candida infections are a major cause of infectious morbidity and mortality during chemotherapy-induced neutropenia. Because of the unreliability of conventional diagnostic tests to detect systemic infection early in its course, treatment of established disseminated Candida infection has been generally disappointing with mortality rates of 60-80% in leukemia and bone marrow transplant patients and 30-40% in solid tumor patients. The use of empiric amphotericin B in patients with fever not responding to empiric antibacterial agents has been shown to be successful in reducing morbidity and mortality from fungal infections. However, its toxicity has mitigated the success of this approach. Fluconazole given prophylactically at the institution of chemotherapy has been shown to be a safe and effective alternative. It, however, is not active against all fungal species, especially Aspergillus and some of the less virulent Candida species. Some centers have reported break-through infections by these less susceptible organisms. Whether or not these limitations in its spectrum of activity will limit its usefulness in the future remains unanswered at this time and could pose a cloud to an otherwise bright promise.


Comparison of the survivals between bone marrow transplantation and chemotherapy for acute leukemia in first remission--a Japanese single institution study.

The outcome of sixty-four patients with acute leukemia in first remission who had been treated with either bone marrow transplantation (BMT) or conventional chemotherapy was retrospectively evaluated (a median follow-up of 37 months). Among them, 26 patients (age range; 14-42 years) received allogeneic BMT from HLA-identical siblings and 38 patients (age range; 13-43 years) who had no HLA-identical donors undertook the continued combination chemotherapy. Kaplan-Meier product-limit estimate of actuarial survival of acute myelogenous leukemia (AML) patients was 48.9% for the BMT group and 15.7% for the chemotherapy group (p = not significant, NS). For acute lymphoblastic leukemia (ALL) patients, the survival following BMT was 80.2% and was significantly higher than that of the chemotherapy group of 33.3% (p < 0.05). The disease-free survival of AML and ALL for the BMT group was 34.3% and 36.5%, respectively, which was higher than that of the chemotherapy group (16.7% and 23.4%, respectively (p = NS)). These findings in our Japanese single institution study suggested that BMT may be the treatment of choice for adult patients with acute leukemia in first remission if they had suitable donors and that more effective therapeutic regimens were necessary for patients without compatible donors in order to obtain the longer remission duration.


AMSA combination chemotherapy in patients with acute myelogenous leukemia unsuitable for standard antileukemic treatment.

Forty-eight patients with acute myelogenous leukemia (AML) not eligible for anthracycline or mitoxantrone treatment, mostly due to cardiac contraindications, were given aggressive therapy using m-amsacrine (AMSA) in combination with conventional or high-dose cytarabine for remission induction. Twenty-nine patients (60.4%) responded to treatment, and complete remission was attained in 19 (39.6%), partial remission in 4 (8.3%) and death in bone marrow aplasia without detectable blasts in 6 patients (12.5%). Median time to granulocyte recovery was 32 days, median duration of relapse-free survival 199 days. One patient experienced a serious cardiac adverse event; nausea and vomiting were observed in 73%, diarrhea in 44%, and hepatoxicity in 29% of patients. All potentially AMSA-related side effects were fully reversible, and a lethal complication did not occur. It is concluded that combination chemotherapy with AMSA and Ara-C is also effective and tolerable in leukemic patients in whom cardiotoxic drugs are contraindicated.


Prognostic value of the histologic classification of peripheral T-cell lymphoma: a clinico-pathologic study of 71 HTLV-1 negative cases.

The histologic and clinical features of 71 cases of peripheral T-cell lymphoma (PTCL) have been studied. All patients were HTLV-1 negative. The T-cell phenotype was demonstrated by immunohistochemistry on cryostat sections (41 cases) and paraffin-embedded sections (30 cases). All cases were histologically classified according to the updated Kiel classification of non-Hodgkin's lymphoma (low and high-grade) and according to a Working Formulation (WF)-based classification (predominantly small cells, mixed small and large cells, and predominantly large cells). Most cases were in the high-grade group according to both classifications. The prognostic value of these two classifications was comparatively assessed. The analysis of the actuarial survival curves showed that, by using the updated Kiel classification, low-grade PTCL had a survival probability higher than high-grade PTCL although the difference was not statistically significant. Similar results were obtained when the WF-based classification was applied: furthermore, actuarial survival curves of mixed small and large cell PTCL, and of large cell PTCL were rather similar, thus indicating that differentiating these two categories has a limited prognostic value.


Leukaemic intermediate lymphocytic lymphomas: analysis of twelve cases diagnosed by morphology.

Twelve cases of leukaemic intermediate diffuse lymphocytic lymphoma (ILL), diagnosed by morphology, were analysed. The morphology of the ILL cells was so typical that it allowed ready distinction from chronic lymphocytic leukaemia (CLL) and other related B cell disorders. All cases were of B derivation, had strong mu and chi or lambda immunoglobulin (Ig) staining, were CD5 and FMC7 positive and CD10 negative. Cytogenetic abnormalities were found in 8 patients all having t(11;14)(q13;q32). DNA analysis revealed a relatively high incidence of hypoploidy. At diagnosis all the patients (9 males, 5 females; median age 68) had a low degree of absolute lymphocytosis but the disease was advanced and mostly widespread. The course of the disease appears to be aggressive and incurable with conventional combination chemotherapy.