Comparative efficacy of house dust mite extermination products.

The acaricidal efficacy of nine marketed products, i.e. Acardust, Acarosan (foam and powder), Actelic 50, Artilin 3A (spirit and water base), liquid nitrogen, Paragerm AK, and Tymasil, and of intensive vacuum-cleaning have been compared on four different test surfaces: mattress, tufted carpet, gypsum board and rough wooden board, all covered with artificial house dust. They were inoculated with the house dust mite, Dermatophagoides pteronyssinus or the house-dust fungus Aspergillus repens for evaluation of the fungistatic claims of some products. The acaricidal activity of Tymasil did not surpass that of vacuuming; its fungistatic effect was not apparent. The other products showed complete to almost complete eradication on at least one of the substrates tested. Taking into account the results of acaricidal efficacy as well as the data on safety and practicality acquired earlier, Acarosan powder was considered first choice for carpet treatment. Acarosan and liquid nitrogen, were found to be effective in the treatment of mattress, pillow, upholstered furniture and heavy curtains. On wooden surfaces Acarosan was found to be both effective and safe, while Acardust, Actelic 50, Artilin 3A (both fungistatic as well as acaricidal), liquid nitrogen and Paragerm also passed the efficiency test.


Influence of a positive family history and associated allergic diseases on the natural course of asthma.

The outcome of childhood asthma was studied in a cohort of 406 asthmatic children, with emphasis on the influence of family history for allergic disease, as well as the influence of associated allergic diseases on prognosis. Sixty-two per cent had a positive family history for atopy. In young adulthood no differences, either in symptoms or lung function were demonstrated in comparison to subjects with a negative family history. Fifty-two per cent of the children had no other allergic disease, 48% had either eczema or hay fever or both. When subjects were stratified based on associated allergic disease, no differences in outcome in adulthood were revealed either. It is concluded that neither a positive family history, nor concurrent associated allergic diseases in the child contribute to the prognosis of asthma from childhood to young adulthood. Therefore, environmental factors as well as patient characteristics (including lung function level, level of bronchial responsiveness) are likely to be more important for the prognosis.


How allergenic are hypoallergenic infant formulae?

In a comparative study six different protein hydrolysates, marketed as 'hypoallergenic' infant formulae were investigated by skin prick tests, RAST, RAST inhibition and titrated provocation tests. When hydrolysates containing a high percentage of larger peptides were found to have the highest capacity to induce positive skin tests, provocation tests and to bind to human serum IgE antibodies of cow's milk allergic children. Casein hydrolysates appeared to have the least residual allergenic activity. We recommend that 'hypoallergenic' formulae should be tested in each case, before being prescribed to cow's milk sensitive children.


The effect of intranasal azelastine, Rhinolast, on nasal airways obstruction and sneezing following provocation testing with histamine and allergen.

The effect of single dose topical nasal therapy with azelastine hydrochloride (azelastine) on the response of nasal airways resistance (NAR) to provocation testing was studied in 36 patients with seasonal allergic rhinitis. Nasal provocation testing (NPT) with histamine or grass pollen was performed after a single dose of azelastine, 0.28 mg to each nostril, or placebo. NAR was assessed by rhinomanometry for 10 hr following NPT. Compared to placebo the NAR response to histamine was inhibited at both 1 and 2 hr following azelastine administration, significant at 1 hr (P less than 0.02) and 2 hr (P less than 0.0001). No such effect was observed in relation to allergen-induced changes in NAR. Azelastine also inhibited numbers of sneezes for up to 10 hr following both histamine NPT (P less than 0.02) and allergen NPT (P less than 0.05), when compared to placebo. Forty-seven per cent of participants experienced bitter or unpleasant taste sensations after azelastine administration but no other unwanted effects were clearly related to azelastine therapy.


The allergen specific B-cell response during immunotherapy.

The paper examines the allergen specific B-cell response in peripheral blood from patients undergoing immunotherapy with house dust mite extract. The 12 patients were part of a double blind placebo controlled study, and they were treated with either Dermatophagoides pteronyssinus (n = 4), Dermatophagoides farinae extract (n = 3) (Alutard SQ, ALK, Denmark) or placebo (n = 5). Blood was taken every fortnight on day seven after hyposensitization and tested for IgM, IgG, IgA and IgE antibody secreting cells (AbSC) to D. pteronyssinus and D. farinae allergens and for the total number of immunoglobulin secreting cells (IgSC). The data showed a maximum of approximately 120 Der f I+II specific AbSC/10(6) mononuclear cells (MNC). A comparison of specific AbSC to the major allergens of the two house dust mites demonstrated that there was no measurable species specificity in the B-cell response that could be correlated to immunotherapy with either of the two extracts. The specific IgM, IgG, and IgA response to Der f I+II was examined in the placebo (39 measurements) and the actively treated (56 measurements) groups, and the results demonstrated a significant rise in specific IgM and IgA AbSC following immunotherapy. The number of specific IgG AbSC did not change. There was a mean of less than one specific IgE AbSC/10(6) MNC, and no detectable change following the treatment. It is speculated that immunotherapy to inhalant allergens causes the induction of specific IgA AbSC. It would then be these partly differentiated plasma cells that are detected on their way to the bronchial or gut mucosa to exert their protective function mediated by allergen specific secretory IgA.


Enhanced precision with dual-energy X-ray absorptiometry.

Repeat spine and femur measurements (5 per case) were done on 19 subjects with the DPX-L densitometer operating at 3 mA giving a radiation flux fourfold higher than the earlier DPX model. The precision for spine bone mineral density (BMD) was about 0.55% (L2-L4) and 0.48% (L1-L4) for 2-minute scans (2.4 mrem). The precision was only slightly lower (0.4-0.5%) for 4-minute scans (5 mrem) in a subset of 11 subjects. There was a slight precision advantage for the larger L1-L4 area compared with L2-L4 for 2-minute scans, but no advantage for 4-minute scans. The precision for femoral neck BMD was 1.00 and 0.85% for 2- and 4-minute scans, respectively, with proper positioning. The corresponding values for the Ward's triangle region of the femur were 2.6 and 1.5%. The precision of spine scans was influenced chiefly by variable region location. The precision of femur scans was affected by both patient positioning and location of the region. The 4-minute scans minimized the number of operator changes necessary for analysis. Precision errors can be reduced by up to 50% with utilization of the higher flux, but this does not obviate the need for care in patient positioning and scan analysis.


Nasal human calcitonin for tumor-induced hypercalcemia.

We treated four hypercalcemic cancer patients by nasal hCT, 3 x 2 mg daily, which has been reported to be active in Paget's disease at lower doses. Only one patient became normocalcemic and mean (+/- SEM) calcium levels fell from 11.6 +/- 0.2 mg/dl before therapy to 10.7 +/- 0.6 mg/dl 2-3 days after starting hCT. The tolerance was excellent but, because of insufficient efficacy, we do not recommend this form of therapy for cancer hypercalcemia.


Idiopathic juvenile osteoporosis: evidence of normal osteoblast function by 1,25-dihydroxyvitamin D3 stimulation test.

Idiopathic juvenile osteoporosis (IJO) is a rare form of bone demineralization that occurs during childhood. The mechanism of bone loss is unclear. Some bone hystomorphometric studies have found osteoblast failure and decreased bone formation in the affected patients whereas others have reported increased bone resorption. To elucidate this issue, we studied osteoblast function in six patients with IJO (five males, one female; aged 2.3-14.6 years) and five healthy sex- and age-matched subjects (four males, one female; aged 2.0-15.1 years) measuring serum values of osteocalcin under basal condition and during an osteoblast stimulation test performed by oral 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] administration (1.8 micrograms/1.73 m2/daily). After a baseline day (day 0), all the subjects (patients and controls) received 1,25(OH)2D3 in four divided doses for 6 days (days 1-6). Fasting blood samples were obtained every morning (0800 h) for the determination of serum osteocalcin. Baseline osteocalcin levels were not significantly different between IJO and controls (13.58 +/- 6.05 ng/ml versus 16.04 +/- 5.09 ng/ml, respectively) even if two patients had low osteocalcin values. During 1,25(OH)2D3 administration, serum osteocalcin values significantly increased (P less than 0.001) from baseline in both children with IJO and controls, reaching peak values not significantly different in the two groups. Our results do not support the hypothesis that defective osteoblast function is the primary factor of bone demineralization in IJO.


Decrease in bone level of 1,25-dihydroxyvitamin D in women over 45 years old.

The most active metabolite of vitamin D is 1,25-dihydroxyvitamin D [1,25(OH)2D]. Its level in the bone may play a role in the pathogenesis of metabolic bone diseases such as osteoporosis. To assess this, and to see whether there is correlation between serum and bone levels, we studied serum and bone samples taken from 43 patients (18 men and 25 women) undergoing different orthopedic procedures. Patients were studied according to sex and age groups (less than 45 years, 46-60 years, greater than 61 years). Serum level of 1,25(OH)2D was found to be 29.7 +/- 2.61 pg/ml (mean +/- SEM) for women, 32.2 +/- 3.86 pg/ml for men, and 30.7 +/- 2.18 pg/ml for the group as a whole. No significant statistical differences were found among age subgroups in either sex or between sexes. Bone level of 1,25(OH)2D was found to be 31.5 +/- 4.46 pg/g for women, 26.5 +/- 3.06 pg/g for men, and 29.4 +/- 2.81 pg/g for the entire group. No significant statistical difference was found between the age subgroups for men. However, the level of 1,25(OH)2D was found to be higher in the group of younger women (less than 45 years) compared with the older women (46-60 years and greater than 61 years) (P less than 0.005).


Normocalcemia with persistent increase of parathyroid hormone: a prospective study.

Twelve patients were followed up for 3 months after parathyroidectomy. Serial measurements of serum parathyroid hormone (PTH), calcium, and phosphate were made. Four patients had an increased serum PTH postoperatively, which was already apparent by the third postoperative day. All patients became normocalcemic. Their hyperparathyroid-like phosphate parameters indicated that we were dealing with a biologically active PTH. Using preoperative biochemical parameters it was impossible to predict which patients would have an increased PTH postparathyroidectomy (PTX). Probably the patients with high PTH post-PTX had higher parathyroid volumes. In our opinion after PTX, a normocalcemic high PTH situation should be avoided by 3 1/2 parathyroid gland extirpation in all cases.


Synthetic parathyroid hormone-like protein (1-74) is anabolic for bone in vivo.

Parathyroid hormone-related protein (PTHRP) has recently been purified from human tumors associated with the syndrome of humoral hypercalcemia of malignancy. The gene encoding PTHRP has been cloned, and based on predicted amino acid sequence, polypeptides comprising the first 36 [36Tyr(1-36) PTHRP amide] and 74 [(1-74)PTHRP] amino acids have been synthesized. Human (h) PTHRP (1-36) and (1-74) are potent bone-resorbing agents, and are catabolic for bone in vivo when given continuously at high doses. Bovine parathyroid hormone (bPTH) (1-34) is also catabolic for bone at high dose levels, but when given in low doses for weeks to months, it is anabolic. Although PTHRP possess several PTH-like properties in bone, hPTHRP (1-34) is reported to be only weakly anabolic in vivo. As polypeptide length influences PTHRP action, we evaluated hPTHRP(1-74) as an anabolic agent for bone in vivo. Twenty-four 4-week-old male Sprague-Dawley rats were given daily subcutaneous injections of hPTHRP(1-74) (1 and 2 nmol/100 g body weight, bw), bPTH(1-34) (4 nmol/100 g bw) or vehicle. Rats were sacrificed on day 12, and serum calcium, phosphorus, and 1,25 dihydroxyvitamin D and femoral bone dry weight, calcium content, and hydroxyproline content were measured. Serum calcium and phosphorus were equivalent in all groups. A significant increase in dry bone weight was observed in both PTHRP-treated groups compared with controls. PTHRP also caused a significant, dose-dependent increase in bone calcium and hydroxyproline content. Results of these studies indicate that PTHRP (1-74) is anabolic for bone in vivo when administered at low-dosage levels for a prolonged period.


Risk for developing osteoporosis in untreated premature menopause.

The bone mineral density (BMD) of the lumbar spine and proximal femur was determined by dual photon absorptiometry in 32 women with untreated premature menopause (cessation of menses before 45 years of age). The BMD of the spine and proximal femur in four obese patients was not different from the BMD of the age-matched controls. On the contrary, the BMD of the nonobese females with premature menopause was significantly lower with respect to the average values found in healthy young women, in age-matched and menopause-matched controls. The BMD deficit was greater over the lumbar spine than in the proximal femur. Forty three percent of nonobese patients were already under the vertebral fracture threshold and 25% of nonobese patients were below the hip fracture threshold. The BMD deficit in the lumbar spine was correlated to the loss observed in the femoral neck (r = 0.59, P less than 0.001), in the trochanter (r = 0.65, P less than 0.001) and in the Ward's triangle (r = 0.73, P less than 0.001). A negative correlation was observed between years of menopause and the BMD of the lumbar spine (r = -0.39, P less than 0.05). The results indicate the high individual risk for osteoporotic fractures in nonobese females with untreated premature menopause. The BMD loss was greater over the skeletal areas that are predominantly composed of trabecular bone compared with cortical bone.


Ca2+ uptake by endoplasmic reticulum of renal cortex. II. Effects of uninephrectomy and parathyroidectomy.

Calcium uptake by the endoplasmic reticulum (ER) is important for cellular calcium homeostasis, yet its regulation in nonmuscle cells is poorly understood. We reported that Ca2+ uptake by a light fraction of canine renal cortical ER (LER) is stimulated by protein kinase C in vitro. Here we describe conditions in vivo that stimulate renal cortical LER Ca2+ uptake. Thirty minutes after contralateral nephrectomy in the dog, 45Ca2+ uptake into renal cortical LER was increased 42% above control LER. There was no difference in LER Ca2+ uptake 24 hours after uninephrectomy. Acute denervation did not reproduce the increase in LER 45Ca2+ uptake seen at 30 minutes after uninephrectomy, nor did prior thyroparathyroidectomy abolish it. Forty-eight hours after thyroparathyroidectomy, 45Ca2+ uptake activity into renal cortical LER was decreased approximately sevenfold. In a proximal tubular cell line (LLC-PK1), 30-minute incubation with 12-O-tetradecanoylphorbol-13-acetate doubled 45Ca2+ uptake into a nonmitochondrial pool. Pretreatment with epidermal growth factor halved ER Ca2+ uptake, whereas insulin-like growth factor and growth hormone, alone or in combination, had no effect. Our data suggest that Ca2+ uptake into renal cortical ER is stimulated acutely during compensatory renal growth, perhaps through protein kinase C, and is stimulated chronically by parathyroid hormone.


Osteoclast precursors circulate in avian blood.

The osteoclast is known to be derived from a marrow-residing precursor that is a member of the mononuclear phagocyte family, but the means by which this cell moves from marrow to bone is unknown. We herein demonstrate that mononuclear progenitors capable of differentiating, in vitro, into cells exhibiting the osteoclast phenotype circulate in chickens. The mononuclear fraction was isolated on a density gradient from blood drawn from calcium-deprived laying hens and the plastic-adherent population was obtained. These cells are members of the mononuclear phagocyte family, as demonstrated by nonspecific esterase and tartrate-resistant acid phosphatase (TRAP) activities, expression of the macrophage-specific mannose receptor, and their ability to phagocytose latex particles. When cultured in the presence of devitalized bone, these cells undergo progressive multinucleation and ultimately become essentially indistinguishable from isolated osteoclasts and those generated from bone marrow precursors. Specifically, the blood-derived polykaryons are TRAP-positive, exhibit characteristic ruffled membranes, and express the osteoclast antigens 121F and 23C6. When placed on bone slices, these cells form typical resorptive "pits." Moreover, when cultured with 3H-proline-labeled bone, the blood monocyte-generated osteoclasts mobilize matrix as effectively as those derived from marrow. Thus, osteoclast precursors circulate in the blood of laying hens and can be induced to differentiate in vitro.


Kinetics of beta-glycerophosphate-induced endochondral mineralization in vitro. Calcium accumulation, alkaline phosphatase activity, and effects of levamisole.

Isolated mesenchymal limb bud cells from day-12 mouse embryos grown at high density in organoid culture at the medium/air interphase differentiate into chondrocytes and form cartilage nodules. Upon addition of beta-glycerophosphate (beta-GP), cartilage undergoes endochondral mineralization. This beta-GP-induced mineralization was investigated by measuring the calcium content in the cultures and the activity of alkaline phosphatase (AP) in the cell mass and the medium. Calcium incorporation depended on the amount of beta-GP added. After continuous treatment, mineralization began on day 8 of the culture period and increased linearly until day 15. In long-term cultures, periodical treatment for 6 days caused an increase in mineralization the older the cultures were, but the slope of increase was proportionately less steep. Treatment at the latest period on days 19-24 resulted in a markedly reduced mineralization. After short-term treatment (48 hours), mineralization increased also the older the cultures were and proceeded during further cultivation in beta-GP-free medium. This kinetic behavior indicates a dependency of mineralization on cartilage maturation in this in vitro system. AP activity increased enormously and nearly logarithmically in the cell mass in beta-GP-free medium, whereas beta-GP treatment inhibited this drastic increase. In the medium, considerable activities of AP were also measurable from day 10 onward. It increased in beta-GP-free medium up to day 14, but was diminished after mineralization had been induced. Levamisole inhibited AP activity dose dependently when added directly to the enzyme-containing medium (100% inhibition at 10(-3) M).(ABSTRACT TRUNCATED AT 250 WORDS)


Alkaline phosphatase and peptidase levels in invertebrate cartilage.

Cartilage is encountered in the skeletons of many advanced invertebrates, yet it never calcifies or is replaced by bone. In an attempt to account for the absence of bone in invertebrates, we tested a hypothesis proposing that absence or inadequate quantities of several enzymes associated with vertebrate osteogenesis may underlie the failure of the invertebrates to evolve bone. The enzymes examined were alkaline phosphatase, alanyl beta-naphthylamidase, and neutral protease. Their activities were measured in the gill cartilage of the Atlantic horseshoe crab, Limulus polyphemus, and the odontophore cartilage of the marine whelk, Busycon canaliculatum. Animals were collected from the Cape Cod area. Samples of cartilage of Limulus perichondrium, various non-skeletal tissues, and neonatal rat calvaria, the latter as a reference standard, were homogenized in 0.1 M phosphate buffer (pH 7.1) and analyzed for protein content and the above-mentioned enzyme activities. Alkaline phosphatase specific activity was readily detected in most tissues except the invertebrate cartilage specimens in which it was present only at near-trace levels. Naphthylamidase and protease activities were present in all tissues. In a single experiment, higher phosphatase values were recorded for Limulus cartilage retaining perichondrium, but in a subsequent trial assaying cartilage retaining perichondrium, denuded cartilage, and isolated perichondrium separately, it was demonstrated that phosphatase activity resided primarily within the perichondrium. Exposure of thick cryostat sections to p-nitrophenyl phosphate confirmed the suspicion that alkaline phosphatase activity was present principally in the perichondrium.(ABSTRACT TRUNCATED AT 250 WORDS)


Determination of histamine and polyamines in calcified tissues of mice: contribution of mast cells and histidine decarboxylase to the amount of histamine in the bone.

A simple method for determining histamine and polyamines in various tissues was devised. The method, however, could not be applied to calcified tissues, because the high concentration of Ca2+ in the extract interferes with the chromatographic separation of these amines. By treating the extracts from calcified tissues with K2CO3, we succeeded in removing the Ca2+, and the method could then be applied to determine the amines in bone tissues of mice. By using this method, we examined the contribution of mast cells and histidine decarboxylase (HDC) to the amount of histamine in the bone. The results indicate that (1) the HDC activity in the bone is the highest among the tissues of normal mice, and the histamine produced by the HDC in the bone is metabolized rapidly; (2) a major part of HDC in the bone is present in the bone marrow cells other than mast cells, and most of histamine in the bone is attributable to the histamine pooled in mast cells; (3) mast cells in the diaphysis are located largely along the endosteal lining; and (4) the method devised in this study may be useful for studying the roles of histamine (or mast cells) and polyamines in calcified tissues.


An FT-IR microscopic investigation of the effects of tissue preservation on bone.

Fourier transform infrared microscopy is a powerful tool for the characterization of mineral and protein in histologic sections of bone. This study was concerned with determining whether techniques used to preserve these tissues and to prepare them for sectioning had an effect on spectral properties. The nu 1, nu 3 phosphate bands in the 900-1200 cm-1 spectral region were used to evaluate the structure of the apatitic mineral in fresh-frozen, ethanol-fixed, and formalin-fixed 35-day-old rat femurs; fresh-frozen and formalin-fixed 20-day-old fetal rat femurs; ground 35-day-old rat diaphyseal bone samples; and formalin-fixed, methacrylate-embedded ground diaphyseal bone. The crystallinity (crystal size and perfection) of the bone apatite was assessed by a curve-fitting analysis of the nu 1, nu 3 phosphate bands. Results indicate that ethanol or formalin fixation of the 35-day-old intact rat femur, and formalin fixation and embedding of the ground rat bone do not significantly alter the crystallinity of the apatite. However, formalin fixation of the fetal rat bone did alter the structure of the apatite mineral phase. In addition, evaluation of protein secondary structure in the 35-day-old rat femur from the Amide I and Amide II vibrations near 1650 and 1550 cm-1, respectively, revealed that protein conformation was altered by ethanol fixation.


Calcium biomineralization in the radular teeth of the chiton, Acanthopleura hirtosa.

A method has been devised for isolating the calcium biomineral from the iron biominerals and organic components present in the major lateral teeth of the chiton Acanthopleura hirtosa. Fourier-transform infrared spectroscopy of the calcium biomineral indicated that it was an apatite material containing carbonate and fluoride ions. Carbonate was not found to be present as a separate phase. The apatite was further separated into low and high density fractions, both of which showed crystallinity intermediate between that of bovine tibia cortical bone and human tooth enamel, as indicated by powder X-ray diffraction analysis. The calcified region of the major lateral teeth was also studied in situ using transmission electron microscopy and electron diffraction analysis, revealing a close spatial relationship between the mineral apatite phase and underlying organic matrix. It is suggested that the architectural arrangement of apatite biomineral and fibrous organic constituents imparts specialized mechanical properties to the tooth making it ideally suited for the task of obtaining food from hard surfaces.


CT image analysis of the vertebral trabecular network in vivo.

A method of computed tomography (CT) image analysis of lumbar vertebrae has been developed, providing a visualization of the trabecular network as it is represented in a 1.5 mm-thick CT image. We measured the length of the network and the number of discontinuities found in the image. The ratio of these measurements was called the "trabecular fragmentation index" (TFI). CT images from 71 women between the ages of 50 and 59, and 94 women between the ages of 60 and 69 were divided into three groups according to quantitative computed tomography (QCT) vertebral density and to the presence or absence of crushing and fractures. The measure of the network length versus the vertebral area was significantly higher in normal subjects than in osteoporotics. A TFI threshold at 0.195 could separate the normal subjects, regardless of the decade, from osteoporotic ones. In females between 50 and 69 years of age, TFI was 0.166 (SD = 0.031) for the normal group and 0.248 (SD = 0.082) for osteoporotics. The osteopenic group without fractures but low bone mineral density (BMD) showed an intermediate TFI of 0.195 (SD = 0.05), placing this population on both sides of the threshold. Correlation between TFI and BMD was only -0.60. TFI could provide new information in vivo about the state of trabecular structure, particularly in the osteopenic group.


Soft tissue calcification induced by iron complexes.

Complexed iron (III) induces a local calcification of soft tissues in mice that is strongly dependent upon the nature of the complexing molecule. Ferric lactate is much more effective in inducing calcification than iron dextran.


Hiring the best and the brightest.

Successful dentistry in the nineties demands a well-trained staff who are effective decision makers, team players and committed to excellence. The key to fulfilling this order begins with you, the dentist. It is incumbent on you to invest serious time and thought into the selection of staff. If you do so, you'll likely be surrounded by people who will turn your vision into reality. If you don't, you'll be caught in a staffing quagmire, and your practice vision will remain all-elusive.


Esthetic alternatives for posterior teeth: porcelain and laboratory-processed composite resins.

Porcelain and laboratory-processed composite inlays and onlays are enjoying increasing popularity as a result of heightened patient concern over the esthetics and biocompatibility of restorative materials. This paper reviews current clinical concerns about porcelain and indirect composite restorations, focusing on indirect procedures, microleakage, technique sensitivity, long-term serviceability, finish and polish, abrasion, and wear resistance. The available data indicate that there are still significant limitations to the routine use of these esthetic alternatives for posterior restorations.


A critical view of the rationale for routine, initial and periodic radiographic surveys.

Most dentists and dental faculties use an initial radiographic survey for the comprehensive-care patient rather than selective radiography, as recommended by professional organizations and radiation protection agencies. Survey or screening radiography has been justified in the belief that it is an essential health service designed to disclose serious occult disease and that failure to use such films might expose the dentist to successful malpractice litigation. However, incidence data indicate the chance of disclosing tumors, non-inflammatory cysts or other serious bone disease in the asymptomatic patient by screening jaw films is infinitesimal. On this basis, the practice is not justifiable as a public health measure, nor is the dentist who follows published national guidelines for prescription radiography vulnerable to successful litigation.


Dental management of anticoagulated patients.

Today's trend toward ambulatory medical care will bring more pharmacological problems into the dental office. While the dental management of patients taking oral anticoagulants is controversial, current research supports the contention that they can be safely treated on an outpatient basis. The use of the International Normalized Ratio (INR) has made better estimates of prothrombin time possible, and patients can be maintained in a narrow therapeutic range. Postoperative hemorrhage can be avoided or controlled with local hemostatic agents.


[Risks and benefits of extraction of impacted third molars: A critical review of the literature. 2].

In part I of this critical review of the literature on the risks and benefits of removing impacted third molars, we have dealt with: I--Risks of non-intervention. This second part is about: II--Risks of intervention, III--Benefits of non-intervention, and, finally, IV--Benefits of intervention.


Evaluation of corneal topography: past, present and future trends.

The keratometer and photokeratoscope have long been the standard instruments for measuring corneal curvature. The recent development of computer-assisted photokeratoscopy has greatly enhanced the evaluation of corneal topography, helping improve our understanding of both normal and abnormal topography and their influence on visual acuity. The authors review normal corneal topography and compare various tools, both new and old, currently available for evaluating corneal contour. Case studies are presented to illustrate some of the clinical and research applications of computer-assisted photokeratoscopy in an ophthalmology practice. Future applications of computer-assisted photokeratoscopy include intraoperative topography, the design of custom-fitted contact lenses and combination with ray-tracing analysis.


Eye injuries in Canadian sports and recreational activities.

Over 4000 eye injuries, including 449 blind eyes, have been reported in sports and recreational activities in Canada over the past 20 years. This is not only a great personal loss but also a financial loss, both to the injured person and to the community. Statistics should be tabulated on catastrophic injuries that leave the person with a physical or mental deficit, such as a blind eye, and efforts should be directed toward preventing such injuries. Changing and enforcing game rules and providing proper eye protection has proved very beneficial in Canadian hockey, racket sports and war games. Educational programs supported by the media and government that alert players to the need for eye protection are required. Such measures may lead to the prevention of up to 90% of injuries in sports and recreational activities in Canada.


Implementation of a computerized information system in a long-term care facility.

The successful implementation of computerized nursing information systems requires the completion of many tasks and the participation of many persons. In 1989, Pulliam and Boettcher described a six-step process for introducing computerized information systems into long-term care facilities. This article describes the process, particularly the implementation phase, as it actually happened in a 124-bed facility in a mid-Atlantic state. This facility found that successful implementation requires a systems coordinator who is a professional nurse who understands the needs of the patients, can integrate information with the computer system, and can provide on-going support for the users.


Effect of combined peribulbar and retrobulbar injection of large volumes of anesthetic agents on the intraocular pressure.

A prospective randomized study was done in 79 patients undergoing elective routine cataract surgery in which the Kelman phacoemulsification technique was used with placement of an intraocular lens. In all the patients anesthesia was induced with both a peribulbar and a retrobulbar injection of a large volume (total 10.5 mL) of local anesthetic. The patients were randomly assigned to receive either the peribulbar (39 patients) (group 1) or the retrobulbar (40 patients) (group 2) injection first. The intraocular pressure (IOP) was measured five times during anesthesia. The mean elevation in IOP immediately after the first injection was 0.4 mm Hg in group 1, compared with 2.0 mm Hg in group 2. Twenty minutes after both injections had been given and a Super Pinky pressure device had been placed on the eye, the mean decrease in IOP from the preoperative value was 3.1 mm Hg in group 1 and 4.8 mm Hg in group 2. We conclude that a combined peribulbar and retrobulbar approach is a safe and effective alternative method of regional anesthesia for cataract surgery.


Treatment of encapsulated blebs with 30-gauge needling and injection of low-dose 5-fluorouracil.

We describe a simplified needling procedure, performed at the slit-lamp, with injection of low-dose 5-fluorouracil to treat encapsulated filtering blebs. Between August 1989 and December 1990 we treated 17 eyes of 14 patients with this procedure. At 2 months 13 of the eyes had needed only one needling procedure. Risk factors for reencapsulation of the bleb were a history of three or more previous surgical procedures (p less than 0.05) and prolonged preoperative use of topical adrenergic drugs (p less than 0.05). At 1 year all but one eye had an intraocular pressure below 21 mm Hg (median 15 mm Hg). Twelve of the eyes had needed more than one needling procedure. There were no serious complications of the 32 procedures performed. The incidence rate of minor complications (wound leaks, corneal erosion and small hyphemas) was 38%.


Long-term course of antimalarial maculopathy after cessation of treatment.

Since 1980 I have examined some 1650 patients for the presence or absence of antimalarial maculopathy. Bilateral, irreversible visual field defects have been diagnosed is 62 patients, 37 of whom have been followed for at least 4 years. The 22 patients who presented with relative scotomas did not lose central visual acuity; over a median follow-up period of 6.0 years 33 (75%) of the eyes maintained their visual field, 5 (11%) showed some improvement in visual field, 4 (9%) lost some visual field, and 2 (4%) manifested small absolute scotomas. Nine (60%) of the 15 patients who presented with absolute scotomas were symptomatic. Over a median follow-up period of 8.8 years 19 (63%) of the eyes in this group lost one or more lines of visual acuity, including 4 (13%) that became legally blind; 19 (63%) lost field owing to an increase in the size of the absolute scotomas (13 eyes) or the development of new absolute scotomas (6 eyes). The results suggest that the visual prognosis is excellent if antimalarial therapy is stopped at an early stage of the disease.


Computer assisted instruction for preoperative and postoperative patient education in joint replacement surgery.

This article describes a comprehensive system for preoperative and postoperative patient education. The system offers a cost-effective method of instruction which encourages patient interaction and practice with decision making. The system was designed for patients undergoing total joint replacement surgery and includes two preoperative lessons, and a third lesson presented postoperatively at the bedside. The computer lessons were developed using data collected by a patient assessment instrument, and collaboratively with input from a nurse clinical specialist, orthopedic surgeon, physical therapist, and computer programmer. In this project, several advantages for using computer assisted instruction for preoperative and postoperative patient education were identified.


A dynamic test system: its development and implementation.

A dynamic test system that uses a computer, commercially available software [Data Base IV], and logical human thinking was designed. The system facilitates construction of a multiple-choice test, places an emphasis on the use of item-analysis statistics, and establishes a feedback mechanism for faculty to use when preparing a multiple-choice examination. Prerequisites to the system, development of the system, test construction, and outcomes are described.


Comparison of threshold and standard Amsler grid testing in patients with established antimalarial retinopathy.

To evaluate the sensitivity of threshold Amsler grid testing in the detection of established antimalarial retinopathy, 30 eyes of 15 patients with bilateral, irreversible field defects were examined with the standard Amsler grid and the threshold Amsler grid. Four eyes (13%) showed significant enlargement of large relative scotomas on testing with the threshold Amsler grid. Although only a small proportion of the eyes demonstrated an increase in the size of the scotoma, the patients had established field defects of varying depth, in some cases absolute scotomas. A prospective study in patients with early disease (i.e., with small, shallow scotomas) may be worth while.


Dye yellow vs. argon green laser in panretinal photocoagulation for proliferative diabetic retinopathy: a comparison of minimum power requirements.

We compared the power required to achieve a retinal burn with the dye yellow laser (wavelength 577 nm) and the argon green laser (wavelength 514 nm) in 49 eyes of 38 patients with proliferative diabetic retinopathy who underwent panretinal photocoagulation. All eyes were treated with both lasers. The dye laser required on average 35.7% less power to achieve a retinal burn than the argon laser (p = 0.0001). With both lasers more power was needed in patients older than 55 years than in those aged 55 years or less and in patients with light skin versus those with dark skin (p less than 0.02). The lower power required with the dye yellow laser allows facilitated photocoagulation in patients in whom treatment with the argon green laser would be problematic.


Choroidal detachment associated with retinal detachment as a presenting finding.

Choroidal detachment along with retinal detachment as a presenting finding is rare. We identified five such cases presenting to our ophthalmology practice between 1964 and 1991. The patient is usually myopic and presents with marked visual loss, profound hypotony and a marked anterior chamber reaction. The pathogenesis seems to revolve around the hypotony and myopia and an unstable choroidal vascular system. Management usually involves a scleral buckling procedure with cryotherapy under direct visualization to release choroidal and subretinal fluid, possibly preceded by a few days of anti-inflammatory therapy. The overall prognosis is poor owing to delays in diagnosis and the postoperative development of proliferative vitreoretinopathy.


The integration of theoretical constructs into the design of computer assisted instruction.

The authors believe that for computer assisted instruction to be an effective instructional tool, it must incorporate the most current theoretical principles related to learning and instruction. To assist future developers of computer assisted instruction, the authors review some of the major constructs from the theoretical foundations of various disciplines and then illustrate the integration of these constructs in the design of a software program entitled SOS--Strategies for Problem Solving.


Late-onset Moraxella catarrhalis endophthalmitis after filtering surgery.

We describe a young man in whom endophthalmitis caused by Moraxella catarrhalis developed 5 years after glaucoma filtering surgery. The infection responded to treatment with broad-spectrum antibiotics, and 2 months after presentation the visual acuity had returned to 20/50. To our knowledge this is the first report of late-onset endophthalmitis due to M. catarrhalis complicating glaucoma filtering surgery.


Favourable outcome in a patient with penetrating intraocular BB pellet injury.

Intraocular BB pellet injuries are a devastating form of ocular trauma with a poor prognosis. The penetration of the eye by the pellet causes a marked disruption of the intraocular contents that in most cases leads to enucleation. We describe a 15-year-old boy who suffered a penetrating intraocular BB pellet injury to his right eye and underwent primary repair of the injury followed by secondary vitrectomy and prophylactic panretinal photocoagulation. The postoperative management was complicated by a retinal detachment; however, this responded to a scleral buckling procedure. Eighteen months after the injury the acuity in the affected eye was 20/30 with a contact lens. To our knowledge this is the first case in which useful vision has been recovered in this type of injury.


Relative persistence capacity of BCG substrains in mouse spleen. Computerized statistical analysis. Multiple comparison.

The relative persistence capacity in mouse spleen of 10 and 9 BCG substrains from liquid and dried vaccines, respectively, was evaluated in two studies. Recoverable BCG colony counts from mouse spleen were determined at given days on solid medium in the two studies during a period of 1-360 and 1-345 days, respectively, after the intravenous BCG vaccination, performed with two different viable units. From 36,000 (study 1) and 21,600 (study 2) recoverable BCG colony counts, 180 and 108 mean relative persistence capacity values were estimated to test the residual virulence during the follow-up time, using computerized statistical analysis. The early and late trends of mean relative persistence capacity of the BCG substrains in mouse spleen were tested by linear regression analysis and analysis of variance and covariance; then with ranked adjusted group mean relative persistence capacity, Gabriel's simultaneous test procedure was performed for multiple comparison to diminish type 1 error in statistical inference and in objective interpretation of the experimental results. The associations of the ranked mean relative persistence capacity of the BCG substrains at the different sacrifice days of mice were also analyzed by Kendall's test of concordance. The early, late, and overall relative persistence capacity reflects the residual virulence of the BCG substrains and provides information on the required protective efficacy (immunogenicity) and adverse reactions (reactogenicity), allowing the appropriate vaccination dose, expressed in viable units of the substrain used, to be determined.


Cooperation between two Thiobacillus strains for heavy-metal removal from municipal sludge.

A mixed culture of two fast-growing bacterial strains for heavy-metal solubilization of municipal sewage sludge has been developed. Strain VA-7 decreases the initial sludge pH (7-8.5) to a value between 4.0 and 4.5. Then, strain VA-4 begins growing and further reduces the pH to values below 2.0. The rapid decrease of sludge pH by a mixed culture through sulfur oxidation into sulfuric acid solubilizes the toxic metals (Cd 83-96%, Cr 16-54%, Cu 85-87%, Mn 91-94%, Ni 78-79%, Pb 28-46%, Zn 82-96%) to levels recommended for intensive use of residual sludge in agriculture. A study of the physiological and metabolic characteristics of these strains revealed that isolate VA-7 is a strain of Thiobacillus thioparus (ATCC 55127), while isolate VA-4 corresponds to a Thiobacillus thiooxidans (ATCC 55128). These bacterial strains possess distinctive physiological characteristics that allow them to easily grow and solubilize heavy metals in municipal sludge.


Modulation of murine macrophage responses stimulated with influenza glycoproteins.

Previously it was reported that influenza virus stimulated, nonspecific resistance was largely due to its glycoproteins, hemagglutinin (HA) and neuraminidase (NA). The enhancement of natural killer cell activity was the intrinsic property of NA and HA. In the present study, the stimulatory effect of these glycoproteins on the murine peritoneal macrophages was studied. Electrophoretically purified glycoproteins, NA and HA, of influenza virus A/USSR/90/77 (H1N1) were administered intraperitoneally to C3H/HeN mice, with or without stearyl tyrosine (ST). Macrophages were isolated and were restimulated with phorbol myristate acetate. H2O2 secretion was determined by horseradish peroxidase dependent oxidation of phenol red assay. HA enhanced H2O2 secretion only in the presence of ST (60 nmol.mg-1.h-1), whereas NA alone stimulated H2O2 secretion (83 nmol.mg-1.h-1), by 6-fold over control (13 nmol.mg-1.h-1), and this stimulation was further increased (136 nmol.mg-1.h-1) in the presence of ST. Interleukin 1 (IL-1) activity was determined by using D10.G4.1 cells. There was a little stimulation of IL-1 activity (less than 1 U/mL) of macrophages isolated from HA-primed of HA+ST-primed mice restimulated with HA. On the other hand, IL-1 activity of macrophages isolated from NA-primed mice restimulated with NA significantly increased (102 U/mL) over control (less than 1 U/mL), and an additional 2-fold increase (231 U/mL) resulted when macrophages from NA+ST-primed mice were used. Tumor necrosis factor (TNF) activity was examined by using L929 cells. Negligible TNF activity was observed in macrophages isolated from either HA-primed or HA+ST-primed mice restimulated with HA.(ABSTRACT TRUNCATED AT 250 WORDS)


Nucleotide sequence analysis of the gene encoding the Caulobacter crescentus paracrystalline surface layer protein.

The entire nucleotide sequence of the rsaA gene, encoding the paracrystalline surface (S) layer protein (RsaA) of Caulobacter crescentus CB15A, was determined. The rsaA gene encoded a protein of 1026 amino acids, with a predicted molecular weight of 98,132. Protease cleavage of mature RsaA protein and amino acid sequencing of retrievable peptides yielded two peptides: one aligned with a region approximately two-thirds the way into the predicted amino acid sequence and the second peptide corresponded to the predicted carboxy terminus. Thus, no cleavage processing of the carboxy portion of the RsaA protein occurred during export, and with the exception of the removal of the initial methionine residue, the protein was not processed by cleavage to produce the mature protein. The predicted RsaA amino acid profile was unusual, with small neutral residues predominating. Excepting aspartate, charged amino acids were in relatively low proportion, resulting in an especially acidic protein, with a predicted pI of 3.46. As with most other sequenced S-layer proteins, RsaA contained no cysteine residues. A homology scan of the Swiss Protein Bank 17 produced no close matches to the predicted RsaA sequence. However, RsaA protein shared measurable homology with some exported proteins of other bacteria, including the hemolysins. Of particular interest was a specific region of the RsaA protein that was homologous to the repeat regions of glycine and aspartate residues found in several proteases and hemolysins. These repeats are implicated in the binding of calcium for proper structure and biological activity of these proteins. Those present in the RsaA protein may perform a similar function, since S-layer assembly and surface attachment requires calcium. RsaA protein also shared some homology with 10 other S-layer proteins, with the Campylobacter fetus S-layer protein scoring highest.


Biodegradation of soil humic acids by Streptomyces viridosporus.

Biodegradation of soil humic acids by Streptomyces viridosporus ATCC 39115 growing in a mineral salts--glucose medium was demonstrated. This biodegradation accompanies bacterial growth and is, therefore, presumed to be a primary metabolic activity, but humic acids were not used as the sole source of carbon. This bacterial activity was enhanced when cells were shaken and within a pH range of 6.5-8.5. In further experiments, the relative abilities of S. viridosporus to mineralized [14C]melanoidin, used as synthetic humic acid, were also established. In contrast to the white rot fungus Phanerochaete chrysosporium, another microorganism exhibiting humic acid degrading activity at acidic pH, poor extracellular activities were found in culture medium of S. viridosporus, and veratryl alcohol does not result in increased humic acid degradation. In spite of some peroxidase activity measured in culture filtrates and analyzed by polyacrylamide gel electrophoresis, the humic acid degrading system of S. viridosporus, in these experimental conditions, seems to be cell associated.


Fonsecaea pedrosoi: lipid composition and determination of susceptibility to amphotericin B.

Conidia and mycelial cells of Fonsecaea pedrosoi ATCC 46428 were obtained for analyses of lipid composition. Total lipids, phospholipids, sterols, and qualitative sterols and fatty acid composition were determined. A higher lipid content was detected in conidia than in mycelial cells of Fonsecaea pedrosoi, which could not be attributed to total sterols and phospholipids. In both forms of this fungus, ergosterol was the only sterol detected. The minimal inhibitory concentration of amphotericin B was lower for conidia than for mycelium.


Cloning of tetracycline-resistance genes from various strains of Clostridium perfringens and expression in Escherichia coli.

One hundred strains of Clostridium perfringens and 52 strains of other clostridia of human and animal origins were screened for tetracycline resistance. Fifty-six strains were resistant to tetracycline in the C. perfringens group. Ten strains were selected for their high level of resistance. In all of them, the tetracycline-resistance genes were found to be residing in large plasmids of about 50 kb, all showing homologies. Several tetracycline-resistance genes from plasmids of various strains of C. perfringens were cloned in plasmid pUC19 and the resistance was expressed in Escherichia coli. Hybridization analysis showed these genes to be homologous among themselves and also to tetP gene from the PCW3-type plasmid.


Microcarrier culture of fish cells and viruses in cell culture bioreactor.

This article deals with the culture of grass carp (Ctenopharyngodon idellus) lip and embryo cells on Cytodex 3 and GT-2 microcarriers in a 1.5-L cell culture bioreactor to propagate grass carp hemorrhage virus. The cells and viruses were successfully cultivated at 26 degrees C, pH 7.0, and dissolved oxygen 40% of air saturation. The cell density achieved was as high as 7.4 x 10(6) cells/mL, and the virus titre reached 6.75 log LD50/0.5 mL from an initial 3.00 log LD50/0.5 mL. The results present broad prospects for fish virus vaccine production.


Recovery of Bacteroides fragilis group from clinical specimens following antimicrobial therapy.

Over a period of 14 years (1973-1987), 3165 specimens submitted to the microbiology laboratory demonstrated the recovery of anaerobic bacteria. A total of 988 Bacteroides fragilis group isolates were recovered (0.3 isolates per specimen). Bacteroides fragilis accounted for 62% of the total of all B. fragilis group isolates, Bacteroides thetaiotaomicron for 15%, Bacteroides vulgatus for 8%, Bacteroides ovatus for 7%, Bacteroides distasonis for 6%, and Bacteroides uniformis for 2%. Of the 988 B. fragilis group isolates, 310 (31%) were recovered after the administration of antimicrobial therapy, and 129 (13%) were the single isolate recovered from the infected site at that time. The recovery rate of all members of B. fragilis group after the administration of antimicrobial therapy, when isolated alone or when mixed with other bacteria, was similar. The data illustrate the equal ability of all members of the B. fragilis group to persist in and to contribute to the inflammatory process; and provide further support for their pathogenic role.


A succinate transport mutant of Bradyrhizobium japonicum forms ineffective nodules on soybeans.

Biochemical evidence has shown that dicarboxylic acids actively support symbiotic nitrogen fixation by both fast- and slow-growing Rhizobium. Mutants defective in the active uptake of succinate have been previously described only in species of the fast-growing rhizobium. This article is a report on the isolation of mutants defective in dicarboxylate transport in a slow-growing species of rhizobium, Bradyrhizobium japonicum. One of these presumptive dicarboxylate transport mutants, GTS, was characterized further. Cultured GTS was unable to accumulate [14C]succinate above background levels but possessed normal rates of malate dehydrogenase, fumarase, and hydroxybutyrate dehydrogenase activities. When inoculated onto soybeans, GTS produced a Nod+, Fix- phenotype. The bacteroids isolated from these nodules failed to accumulate labelled succinate. Electron micrographs of nodules formed by inoculation with GTS appeared normal with the exceptions of more prominent peribacteroid spaces in the infected cells and the appearance of starch granules in the noninfected cells. The phenotypical and morphological changes observed for B. japonicum are similar to those previously reported for the fast-growing species.


Biochemical characterization and time-course analysis of Lymantria dispar nuclear polyhedrosis virus with monoclonal antibodies.

Hybridoma cell lines secreting monoclonal antibodies (MAbs) specific to a 31,000 molecular weight viral protein or a 31,000 molecular weight polyhedrin protein of Lymantria dispar nuclear polyhedrosis virus (LdNPV) were developed. The two polypeptides were shown to be different by comparing their amino acid compositions. Immuno-electron microscopy was used to verify specific binding of the MAbs to their respective targets. Specific MAbs were used to develop an ELISA procedure to monitor the development of LdNPV virus and polyhedrin in vivo. Results indicated that in hemolymph of larvae fed 10(6) polyhedral inclusion bodies, the concentration of virus began to increase 16 h after inoculation and continued to increase for the next 5 days. By 36 h, the concentration of polyhedrin increased and was maintained at a high level in the later stages of infection. One-third of this group of infected larvae survived the infection. In these individuals, the concentrations of virus and polyhedrin declined to a low level 5 days after infection. This suggests the presence of a host mechanism for clearing the virus from the hemolymph.


Effect of nitrogen sources on oxidoreductive enzymes and ethanol production during D-xylose fermentation by Candida shehatae.

The effect on D-xylose utilization and the corresponding xylitol and ethanol production by Candida shehatae (ATCC 22984) were examined with different nitrogen sources. These included organic (urea, asparagine, and peptone) and inorganic (ammonium chloride, ammonium nitrate, ammonium sulphate, and potassium nitrate) sources. Candida shehatae did not grow on potassium nitrate. Improved ethanol production (Y(p/s), yield coefficient (grams product/grams substrate), 0.34) was observed when organic nitrogen sources were used. Correspondingly, the xylitol production was also higher with organic sources. Ammonium sulphate showed the highest ethanol:xylitol ratio (11.0) among all the nitrogen sources tested. The ratio of NADH- to NADPH-linked D-xylose reductase (EC 1.1.1.21) appeared to be rate limiting during ethanologenesis of D-xylose. The levels of xylitol dehydrogenase (EC 1.1.1.9) were also elevated in the presence of organic nitrogen sources. These results may be useful in the optimization of alcohol production by C. shehatae during continuous fermentation of D-xylose.


Sheen formation and growth response of groundwater bacteria to reduced oxygen concentrations during incubation of M-Endo medium.

In vitro pure-culture studies were conducted to assess growth and sheen formation of groundwater bacteria on M-Endo medium incubated under reduced oxygen concentrations (0, 4, 8, 12, and 16%). Coliform and noncoliform bacteria were isolated from 17 untreated, rural groundwater supplies on M-Endo medium. All 16 coliform isolates tested were capable of sheen formation at oxygen concentrations of 4% or greater, yet some of these same isolates (Enterobacter aerogenes, Enterobacter cloacae, and Hafnia alvei) were either unable to grow or failed to produce a metallic sheen when incubated under strict anaerobiosis. Approximately 70% of the 21 noncoliform isolates examined exhibited growth inhibition at oxygen concentrations of 8% or less. The growth of a false-positive coliform isolate of Serratia fonticola was inhibited when incubated under reduced oxygen concentrations of 16% or less. Our findings suggest that the selectivity of M-Endo medium, and resultant inhibition of noncoliforms and false-positive coliforms, is enhanced by incubation in the absence of oxygen. However, the failure of strict anaerobiosis to permit detection of total coliforms such as Hafnia and Enterobacter spp. may compromise the reliability of this technique for evaluating the sanitary quality of some waters. On the other hand, oxygen concentrations of 4, 8, 12, and 16% permitted adequate sheen development of all coliforms tested while inhibiting some noncoliforms.


Binding of mutagenic pyrolyzates to fractions of intestinal bacterial cells.

The binding of mutagenic pyrolyzates to cell fractions from some gram-negative intestinal bacteria and to thermally treated bacterial cells was investigated. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) were effectively bound by several of the bacterial cells. The cell wall skeletons of all bacteria effectively bound Trp-P-1 and Trp-P-2. Their cytoplasmic fractions retained Trp-P-1 and Trp-P-2, but to a lesser extent than the cell wall skeletons. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) was not found in their cytoplasmic fractions. These cell wall skeletons also bound 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-5-phenylpyridine (Phe-P-1), IQ, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX). The amount of each mutagen bound differed with the type of mutagen and the bacterial strain used. The outer membrane of Escherichia coli IFO 14249 showed binding of about 123.7 micrograms/mg of Trp-P-2, and its cytoplasmic membrane bound 57.14 micrograms/mg. Trp-P-2 bound to the bacterial cells was extracted with ammonia (5%), methanol, and ethanol but not with water.


Eradication of biofilm cells of Staphylococcus aureus with tobramycin and cephalexin.

The kinetics of growth and formation of biofilm by Staphylococcus aureus were investigated under iron-limited conditions in the chemostat. The population of planktonic cells reached 5.5 x 10(9) cells/mL 24 h after inoculation (D = 0.05 h-1) and remained constant throughout. The number of biofilm cells of S. aureus colonizing the silicone tubing increased exponentially from 6 x 10(4) to 2.7 x 10(7) cells/cm2 (6 days later) and continued to increase at a reduced rate to 2.7 x 10(8) cells/cm2 on day 13. Planktonic cells of S. aureus were susceptible to tobramycin and cephalexin. The planktonic cells could be successfully eradicated with a combination of 5 micrograms tobramycin plus 100 micrograms cephalexin per millilitre. Exposure of young biofilm cells of S. aureus to 5 micrograms tobramycin plus 100 micrograms cephalexin per millilitre resulted in a rapid loss of cell viability. The percentage of survival dropped to less than 0.0001% after exposure to these concentrations of antibiotics for 3 h. Old biofilm cells of S. aureus were found to be extremely resistant to these antibiotics. The cell viability was reduced to 0.09% after exposure to 10 micrograms tobramycin plus 100 micrograms cephalexin per millilitre. The results suggest that it is possible to eradicate S. aureus infection at the early stage with tobramycin plus cephalexin. Any delay in implementing antibiotic therapy is likely to result in the failure of the treatment. It is important to note that the concentrations of antibiotics required for the eradication of young biofilm cells must be determined for the treatment of device-associated infections.


Relationship of low lysine and high arginine concentrations to efficient ethanolic fermentation of wheat mash.

Very high gravity wheat mashes containing 20 or more grams of carbohydrates per 100 mL were fermented completely by Saccharomyces cerevisiae, even though these mashes contained low amounts of assimilable nitrogen. Supplementation of wheat mashes with various amino acids or with yeast extract, urea, or ammonium sulfate reduced the fermentation time. However, lysine or glycine added as single supplements, inhibited yeast growth and fermentation. With lysine, yeast growth was severely inhibited, and a loss of cell viability as high as 80% was seen. Partial or complete reversal of lysine-induced inhibition was achieved by the addition of a number of nitrogen sources. All nitrogen sources that relieved lysine-induced inhibition of yeast growth also promoted uptake of lysine and restored cell viability to the level observed in the control. They also increased the rate of fermentation. Experiments with minimal media showed that for lysine to be inhibitory to yeast growth, assimilable nitrogen in the medium must be in growth-limiting concentrations or totally absent. In the presence of excess nitrogen, lysine stimulated yeast growth and fermentation. Results indicate that supplementing wheat mash with other nitrogen sources increases the rate of fermentation not only by providing extra nitrogen but also by reducing or eliminating the inhibitory effect of lysine on yeast growth.


Bactericidal properties of peracetic acid and hydrogen peroxide, alone and in combination, and chlorine and formaldehyde against bacterial water strains.

The bactericidal properties of peracetic acid, hydrogen peroxide, chlorine, and formaldehyde were compared in vitro using a rapid micromethod. A combination of peracetic acid and hydrogen peroxide was also tested to assess interactions. The activities of these agents, which are widely used as disinfectants, were evaluated against water isolates and culture collection strains. Peracetic acid and chlorine exhibited an excellent antimicrobial activity, with a relatively rapid destruction of 10(5) bacteria/mL. The time-dependent bactericidal activities of hydrogen peroxide and formaldehyde were the lowest. The combination of peracetic acid and hydrogen peroxide, tested by a checkerboard micromethod, was found to be synergistic. The minimal bactericidal concentration was established in terms of time for a given mixture of peracetic acid and hydrogen peroxide. Determination of bactericidal concentrations showed that synergy was maintained with increasing contact time. Concentrations for minimal times of treatment by chemicals that provided interesting activities in vitro were tested for disinfection of ultrafiltration membranes. The bactericidal activities of peroxygen compounds were confirmed and synergism was maintained in working conditions. Chlorine showed a loss of efficacy when used on membranes.


Alcoholic glucose and xylose fermentations by the coculture process: compatibility and typing of associated strains.

As part of the simultaneous fermentation of both glucose and xylose to ethanol by a coculture process, compatibilities between xylose-fermenting yeasts and glucose-fermenting species were investigated. Among the Saccharomyces species tested, none inhibited growth of the xylose-fermenting yeasts. By contrast, many xylose-fermenting yeasts, among the 11 tested, exerted an inhibitory effect on growth of the selected Saccharomyces species. Killer character was demonstrated in three strains of Pichia stipitis. Such strains, despite their high fermentative performances, cannot be used to ferment D-xylose in association with the selected Saccharomyces species. From compatibility tests between xylose-fermenting yeasts and Saccharomyces species, pairs of microorganisms suitable for simultaneous xylose and glucose fermentations by coculture are proposed. Strains associated in the coculture process are distinguished by their resistance to mitochondrial inhibitors. The xylose-fermenting yeasts are able to grow on media containing erythromycin (1 g/L) or diuron (50 mg/L), whereas the Saccharomyces species are inhibited by these mitochondrial inhibitors.


Serotyping of Bacillus thuringiensis environmental isolates by extracellular heat-stable somatic antigens.

A total of 525 Bacillus thuringiensis environmental isolates, belonging to the five flagellar (H) serovars (alesti, sotto, kenyae, aizawai, and morrisoni), were serotyped by extracellular heat-stable somatic antigens (HSSAs). The isolates belonging to a given H serovar were assigned to a single HSSA serogroup at a high frequency, 87-100%. This indicates that the extent of HSSA variation within a single H serovar is small in the field populations of these B. thuringiensis serovars.


Capsules of Escherichia coli, expression and biological significance.

Escherichia coli may cause intestinal or extraintestinal infections. Generally, extraintestinal E. coli are encapsulated. The capsules are important virulence determinants, which enable the pathogenic bacteria to evade or counteract the unspecific host defense during the early (preimmune) phase of infection. They interfere with the action of complement and phagocytes. This effect is generally transient and overcome by capsule-specific antibodies in the immune phase of the host defense. In some cases, capsules are not or only poorly immunogenic, as a result of structural relationship or identity with host material. Strains with such capsules (e.g., K1 or K5) are very virulent. Bacterial capsules consist of acidic polysaccharides, which are made up from oligosaccharide repeating units. The capsules of E. coli are divided into two groups, which differ in chemistry, biochemistry, and genetic organization. All capsular polysaccharides are chromosomally determined: those of group I close to his and those of group II close to serA. The biosynthesis and surface expression have been extensively studied with representatives of group II capsular polysaccharides. It could be shown that their biosynthesis is directed from a gene block that determines the synthesis of the polysaccharide, its translocation across the cytoplasmic membrane, as well as its surface expression in a coordinate process. The chemical nature of group II capsular polysaccharides, as well as the mechanism(s) of their biosynthesis and expression, is presented.


Mechanism and regulation of synthesis of aerobactin in Escherichia coli K12 (pColV-K30).

The aerobactin operon of the virulence plasmid pColV-K30 of Escherichia coli K12 consists of four genes for biosynthesis and one for transport of the siderophore. Regulation by iron occurs at the transcriptional level and is mediated by a ferrous iron binding protein designated Fur (ferric uptake regulation). The metallated Fur repressor binds at a palindromic dyad, the "iron box" operator, situated in the vicinity of the RNA polymerase attachment site of the promoter. Evidence suggests that the ferrous iron enters the C-terminal domain of Fur to cause a conformational change in the N-terminal part of the protein. This results in greatly enhanced affinity of the repressor for the operator.


Escherichia coli cytotoxins and enterotoxins.

Vero cell cytotoxins and cytotonic enterotoxins produced by E. coli are toxic proteins, which have been implicated in a number of specific diseases in humans and animals. Nomenclature for these toxins is complicated by the existence of different names for the same toxin. The Vero cell cytotoxins are called verotoxins because they are lethal for Vero cells in culture; they are also known as Shiga-like toxins (SLTs) because they are clearly related to Shiga toxin in structure, amino acid sequence, mechanism of action, and biological activity. SLTs belong to two classes. SLT-I is identical with Shiga toxin and is in a class by itself (class I). The other SLTs are closely related to each other and form a second class (class II). Class II SLTs include SLT-II, SLT-IIv, SLT-IIvha, SLT-IIvhb, and SLT-IIva. All SLTs that have been investigated are A-B subunit protein toxins, whose A subunits possess N-glycosidase activity against 28S rRNA and cause inhibition of protein synthesis in eukaryotic cells. These toxins are enterotoxic as well as cytotoxic. SLTs produced in the intestine are absorbed into the blood stream and affect vascular endothelial cells in target organs. They may also have a direct toxic effect on enterocytes. Diseases in which E. coli SLTs have been implicated include diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome in humans and edema disease in pigs. Variation in receptor specificities among SLTs may be the reason for different disease syndromes in different host species. The E. coli enterotoxins belong to three distinct classes: heat-labile enterotoxin (LT), heat-stable enterotoxin type I or type a (STI, STa), and heat-stable enterotoxin type II or type b (STII, STb). There is clear evidence that these cytotonic enterotoxins play an essential role in diarrheal disease. LT is an A-B subunit protein toxin, closely related to cholera toxin. Following binding of LT to receptors in enterocytes the A subunit is internalized. The enzymatically active A subunit transfers ADP-ribose from NAD to a GTP-dependent adenylate cyclase regulatory protein, thereby elevating intracellular levels of adenylate cyclase. The increased levels of cyclic AMP cause stimulation of A kinase and lead to hypersecretion of electrolytes and fluid. STI is a small peptide of 18 or 19 amino acids. It binds to receptors in enterocytes and stimulates particulate guanyl cyclase. Elevated intracellular cyclic GMP stimulates G kinase, resulting in increased Cl- secretion and impaired absorption of Na+Cl-. STII is a peptide toxin whose mechanism of action is unknown.(ABSTRACT TRUNCATED AT 400 WORDS)


Virulence determinants of Escherichia coli: present knowledge and questions.

This paper describes the present state of research on the pathogenicity of Escherichia coli and points out the gaps in knowledge that should be filled in the future. First, the great versatility of E. coli in producing disease is noted, as well as the invaluable contributions that studies of it have made to the development of general knowledge on bacterial pathogenicity. Then, the biological requirements for pathogenicity: infection of mucous surfaces; penetration of those surfaces; multiplication in vivo; interference with host defence mechanisms; and damage to the host, are taken in turn, and an enquiry is made on how far studies have progressed toward identifying their molecular determinants and relating structure to biological action. Only for mucous surface adhesins and protein toxins are studies at the structure-function level. Some progress has been made on interference with host defence, but little is known about competition with commensals on mucous surfaces, invasion into the tissues, and growth in vivo.


Magnetic resonance imaging and 31P magnetic resonance spectroscopy study of the effect of temperature on ischemic brain injury.

Transient forebrain ischemia was induced in rats whose brain temperature was 31, 33, 35, 38, or 40 degrees C. The development of regional injury was followed using magnetic resonance (MR) imaging, with the ultimate extent of neuronal injury quantified histopathologically. Animals in the hypothermic groups showed minimal changes in MR images over 4 days; normothermic animals showed intensity enhancement attributed to progressive edema developing in the striatum and, later, in the hippocampus. Ischemia at 40 degrees C resulted in widespread edema formation by 1 day post-ischemia; animals in this group did not survive beyond 30 hours. Histopathological analysis at 4 days (1 day for the hyperthermic group) post-ischemia showed that neuronal damage in the normothermic group was confined to the hippocampus and striatum. Minimal damage was found in the hypothermic groups; damage in the hyperthermic group was severe throughout the forebrain. There were no differences in the pre-ischemia 31P MR spectra for the different groups. During ischemia, the increase in intensity of the Pi peak and the fall in tissue pH increased with temperature in the order hypothermic less than normothermic less than hyperthermic group of animals. Post-ischemia energy recovery was similar in all groups, while pH recovered more rapidly in hypothermic animals.


Malondialdehyde, glutathione peroxidase, and superoxide dismutase in cerebrospinal fluid during cerebral vasospasm in monkeys.

Cerebral vasospasm may result from lipid peroxidation induced by oxyhemoglobin in the subarachnoid space after subarachnoid hemorrhage. To test this theory, vasospasm was induced in monkeys by intrathecal injections of oxyhemoglobin or supernatant fluid from autologous blood incubated in vitro. Concentration of malondialdehyde (MDA), a product of lipid peroxidation, was elevated in cerebrospinal fluid (CSF) in association with vasospasm caused by oxyhemoglobin and supernatant fluid. Intrathecal injections of methemoglobin or bilirubin did not cause vasospasm or increased CSF MDA. Activity of glutathione peroxidase in CSF increased significantly after injection of oxyhemoglobin and methemoglobin. There were no significant changes in CSF superoxide dismutase activity although there was a trend towards higher activities in animals treated with oxyhemoglobin, methemoglobin, bilirubin, and supernatant fluid. These results show oxyhemoglobin-induced vasospasm is associated with MDA and lipid peroxidation in the subarachnoid space. Furthermore, detection of peroxidation products after injection of oxyhemoglobin in the absence of erythrocyte membranes indicates that oxyhemoglobin may directly damage cerebral arteries and brain by inducing lipid peroxidation in these structures. Depletion of free-radical scavenging enzymes in CSF did not seem necessary for development of vasospasm. In fact, there was a tendency for vasospasm to elevate enzyme activities, as if production of scavengers was induced by excess free radicals in the subarachnoid space.


A Canadian population survey on the clinical, epidemiologic and societal impact of migraine and tension-type headache.

Trained telephone interviewers contacted 1,573 adults across Canada about the nature and frequency of headaches suffered by them or by others in their households. Using a table of pain symptoms and other characteristics abstracted from the International Headache Society (IHS) classification, the headaches were assigned to migraine headache, tension-type headache or other diagnostic groups. Of the households sampled, 59% had at least one headache sufferer in residence. The proportion of headache sufferers with migraine was 14%; with tension-type, 36%; and with both, 14%. Migraine headache caused more disability than tension-type headache, with nearly 20% of migraine sufferers taking time off work and disability lasting for a mean of 1 day. It is concluded that the current prevalences of migraine and tension-type headache in Canada fall around the mean of previous studies, that the IHS criteria can form a basis for diagnostic classification and that the functional impact of migraine has been seriously underestimated in the past.


Comparison of the efficacy and safety of flunarizine to propranolol in the prophylaxis of migraine.

This study was designed to compare flunarizine, a cerebro-specific calcium channel antagonist, and propranolol in the prophylaxis of migraine with or without aura. Following a 1 month single-blind placebo baseline period, 94 patients were equitably randomised under double-blind conditions to take flunarizine 10 mg daily or propranolol 80 mg twice daily for 4 months. Both treatments led to a significant reduction in the frequency of migraines and use of rescue analgesics with a significantly greater decrease in number of attacks for flunarizine after 1 and 4 months. Neither treatment affected the severity nor duration of migraines. Overall, 67% of flunarizine patients and 51% of propranolol patients responded positively. Propranolol significantly reduced blood pressure and heart rate; flunarizine had no effect on cardiovascular function. Weight gain was noted with both treatments. Flunarizine is at least as effective as propranolol in the prophylactic treatment of migraine and may have a better safety profile.


The distinctive clinical features of paraneoplastic sensory neuronopathy.

A 15-year experience with paraneoplastic sensory neuronopathy at the Mayo Clinic is reviewed. Of 26 patients with paraneoplastic sensory neuropathy, 19 had small cell lung cancer, 4 had breast cancer, and 3 had other neoplasms. There was a striking predominance of females (20:6). Neuropathic symptoms (pain, paresthesia, sensory loss) were asymmetric at onset, with a predilection for the upper limbs; in three patients, symptoms were confined to the arms. Electrophysiologic testing revealed absent sensory responses and normal or minimally altered motor responses. Slightly more than half the patients had associated autonomic, cerebellar, or cerebral abnormalities. In some patients, treatment of the neoplasm seemed to halt progression of the neuronopathy, but none had neurologic improvement and most continued to worsen, even when the oncologic response was good. Distinguishing between paraneoplastic and nonparaneoplastic sensory neuronopathies can be difficult, but prominent neuropathic pain, neurologic dysfunction involving more than the peripheral sensory system, or an increased cerebrospinal fluid protein value should prompt a careful search for a cancer.


Ventricular size, cognitive function and depression in patients with multiple sclerosis.

The purpose of this study was to explore further the hypothesis that changes in cognitive function may occur in the mild stages of multiple sclerosis (MS) by determining whether ventricular enlargement was related to cognitive function. Ten measures of ventricular size were made in a sample of 123 MS patients with mild disability and 60 well-matched healthy controls. In addition, sixteen tests of cognitive function and the Beck Depression Inventory were administered. For the MS group, there were significant correlations between the ventricular measures and cognitive performance but not for the normal controls. Scores on the Beck Depression Inventory were not correlated with either cognitive performance or ventricular enlargement. These findings suggest that for the MS group cognitive impairment was related to the disease process but not to the level of depression.


Amyotrophic lateral sclerosis: interleukin-6 levels in cerebrospinal fluid.

Recent observations indicate that antibodies to gangliosides are found in many patients with amyotrophic lateral sclerosis (ALS). If antigen-antibody complexes occur in ALS, elevations of cytokine levels might be expected, among them the cytokine interleukin-6 (IL-6). IL-6 is secreted by activated monocytes and other cell types and is an important mediator of the inflammatory response. We have measured cerebrospinal fluid (CSF) IL-6 levels in patients with ALS and compared them with those in psychiatric and neurodegenerative disorders not believed to be due to immune disorders of the central nervous system. We found no significant differences in CSF IL-6 levels between these groups.


Treatment of acquired autoimmune myasthenia gravis: a topic review.

We propose a new approach to staging the disease based on clinical and immunological response to treatment. We oppose clinical remission to immunological remission and define total clinical remission as the goal of therapy. We describe the use, side effects and indications of established therapies. Acetylcholine esterase inhibitors are only a symptomatic treatment as is plasma exchange. Usefulness and limits of thymectomy, corticosteroids and immunosuppressants are described here. Their goal is to reduce the auto-immune process. Long-term hazards from these medications are described and methods to reduce their potential risks are suggested. We suggest the number of patients having life threatening complications while undergoing aggressive immunosuppression can be reduced by a systematic approach to follow-up. In the second part of this review article, adapting management to specific situations is emphasized in refractory disease, respiratory failure, neonatal and juvenile forms of the disease. The special situation of seronegative myasthenia is discussed.


MRI diagnosis of brainstem cavernous angiomas presenting as tumours.

We report experience with 11 patients misdiagnosed for years, on the basis of computed tomography (CT) and angiography, as harbouring brainstem tumours in whom magnetic resonance imaging (MRI) demonstrated cavernous angiomas. Seven had undergone external irradiation, 2 had a ventriculo-peritoneal shunt, 2 developed aseptic femur necrosis following corticosteroid treatment, 1 had undergone a biopsy with a pathological diagnosis of glioma. CT had depicted ill-defined, hyperdense, faintly enhancing lesions. Angiography was normal, or showed an avascular mass or subtle venous pooling. MRI delineated discrete lesions, typical of cavernous angiomas, with a mixed hyperintense, reticulated, central core surrounded by a hypointense rim. Six patients subsequently underwent stereotactic radiosurgery without changes in clinical status or lesion. Although hemorrhagic neoplasms may mimic the clinical course and MRI appearance of cavernous angiomas, MRI is useful in the diagnosis of brainstem cavernous angiomas and should be performed in patients with suspected brainstem tumours.


Stiff-person syndrome.

The stiff-person syndrome is a disorder of persistent, painful muscle contractions predominately affecting the axial musculature. We describe a patient with this disorder and review its pathophysiology. Molecular biologic and immunologic techniques have recently added to the understanding of the mechanism of this disorder. Association with diseases such as diabetes, vitiligo and hypothyroidism have strengthened the auto-immune nature of this syndrome. Auto-antibodies against glutamic acid decarboxylase (GAD), an intraneuronal enzyme, have been implicated in the etiology of this unique disease. Therapeutic intervention with agents such as benzodiazepines that modify central GABAergic activity have demonstrated significant benefit in patients with stiff-person syndrome.


Spontaneous disappearance of an intracranial aneurysm after subarachnoid hemorrhage.

Spontaneous disappearance of an intracranial aneurysm after subarachnoid hemorrhage is an uncommon event and usually associated with severe cerebral vasospasm, giant aneurysms or the use of antifibrinolytics. We present a young woman who suffered a grade 5 subarachnoid hemorrhage with severe vasospasm caused by a small anterior communicating artery aneurysm. The patient underwent a slow recovery and two years later requested surgery. Angiography demonstrated complete disappearance of the aneurysm. The neurosurgeon should be aware that spontaneous thrombosis of cerebral aneurysms can occur and ensure that angiography is repeated when surgery is significantly delayed.


Intraventricular central neurocytoma.

A case of central neurocytoma treated surgically is described. The authors review the literature. Emphasis is placed on radiological and pathological features not previously described. In particular, the intra-operative ultrasound appearance is described. The role of adjunctive radiotherapy is also discussed.


Survival of breast-cancer patients with previous or subsequent neoplasms.

The authors reviewed retrospectively 1510 patients with breast cancer operated on between 1960 and 1980. They compared 1353 patients who had an isolated breast cancer (group 1) with 157 patients who also had breast cancer but had other cancers either previously or subsequently (group 2). The mean age of patients in group 2 was 2 years more than that of patients in group 1. Group 2 patients had fewer T3 tumours, more T1 tumours (TNM classification), a lower incidence of lymph-node involvement and clinically less advanced tumours than group 1 patients. Hormonal status, histologic type of tumour and surgical and adjuvant treatment were identical in both groups. The 10-year survival rate (considering death from breast cancer) was 54.6% in group 1 versus 78.1% in group 2. The overall survival rate (considering death from breast cancer or from the other cancer) was 54.1% in group 1 versus 64.5% in group 2. Survival was also better in group 2 for each clinical stage. The authors conclude that patients who have another cancer before or after the development of their breast cancer have a better survival rate than those who have isolated breast cancer with no previous or subsequent neoplasms.


Total mastectomy is not always mandatory for the treatment of recurrent breast cancer after lumpectomy alone.

To determine the treatment that offered the best local control for isolated local recurrences of breast cancer after lumpectomy without radiotherapy, the authors reviewed 355 patients initially treated by lumpectomy (with or without axillary dissection) without radiotherapy. Local breast cancer recurred in 79 patients. They underwent either repeat partial mastectomy (PM) or completion total mastectomy (TM). Twenty-four patients (5 TM, 19 PM) received radiotherapy. Local control was defined as the absence of further recurrence of breast or chest-wall cancer. The 19 patients treated with repeat PM and radiotherapy had an actuarial local control rate of 82% at 5 years. Those treated with TM (28 patients) [corrected] or TM plus radiation (5 patients) had rates of local control of 60% and 52% respectively. Although there were no significant differences between the TM and PM plus radiotherapy groups, the 27 patients who had a repeat PM without radiotherapy had a significantly lower rate of local control (32%, p < 0.005). Treatment of recurrent breast cancer with PM and radiotherapy is a viable alternative to TM for enhancing local control. Repeat PM alone gave much poorer results. The authors conclude that local cancer recurrences after lumpectomy alone do not necessarily require TM and can often be treated with repeat excision and radiotherapy.


Surgery for critical aortic stenosis in newborns is still good therapy after 25 years.

Because of the high operative mortality in newborn infants with critical aortic stenosis, new therapeutic modalities have emerged. The authors reviewed their results of surgery for this condition in newborn infants between January 1964 and December 1990. Thirty-seven infants were operated on for critical aortic stenosis, which was diagnosed at a mean patient age of 14.5 days. The surgical procedure was done at a mean patient age of 37 days. Five infants died intraoperatively of ventricular fibrillation at the time of incision. Transventricular valvotomy was attempted in 4 infants, and the remaining 28 infants underwent transaortic valvuloplasty. Overall survival improved markedly in the last 5 years of the study, from 31% to 75%. All patients who had transventricular valvotomy died, as did the only infant with previous percutaneous aortic valvuloplasty. Of the infants who died, 38% weighed less than 3000 g at the time of operation compared with 13% of the survivors (p < 0.05). The duration of cardiopulmonary bypass was also identified as a risk factor (p = 0.001). Of the surviving infants, 93% were followed up at a mean of 66 months. All but one were in New York Heart functional class I or II. The following risk factors were identified for operative mortality: year of surgery, preoperative hemodynamic condition, associated anomalies of the left ventricle, surgical weight less than 3000 g, transventricular valvotomy, year of surgery and prolonged cardiopulmonary bypass. Because of the much improved survival recently, surgery remains a good therapeutic choice for critical aortic stenosis in the newborn infant.


Descending thoracic aortic aneurysms: surgical treatment with the Gott shunt.

Over the past 16 years, 267 consecutive patients underwent surgery for a descending thoracic aortic aneurysm. To provide optimal protection of surrounding organs during aortic occlusion, a 9-mm Gott shunt was used for distal perfusion in all cases. The shunt was placed preferentially between the ascending aorta and the descending aorta; however, alternative sites of proximal and distal cannulation were chosen according to the location and the extent of the aneurysmal disease and the presence of a concomitant aneurysm along the aortic conduit. In one-third of the patients, a flowmeter on the shunt recorded shunt flows, which varied from 1100 mL/min to 4900 mL/min (mean 2526 mL/min). Because the highest shunt flows were obtained with proximal systolic pressures lower than 140 mm Hg, nitroglycerin and nitroprussate were used routinely to improve distal perfusion by arterial vasodilation and release of proximal organs from a circulatory overload. The mean aortic cross-clamp time was 33 minutes for the entire series but was reduced to 25 minutes for the last 140 patients. The hospital death rate was 14.6% overall (12.2% if ruptured aneurysms were excluded). Of the 267 patients, 260 survived the operation and underwent clinical neurologic assessment. No paraplegia or other spinal-cord ischemic deficit occurred.


Central neurogenic tumours of the thoracic region.

Of special concern in the management of neurogenic tumours arising in the thorax is spinal-cord compression resulting from either intraspinal lesions or vertebral-body destruction and collapse. A review of 16 cases disclosed three dumbbell tumours, six intrathoracic tumours, one case of neurofibromatosis with multiple intraspinal neurogenic tumours, two malignant neurogenic tumours with vertebral-body destruction causing spinal-cord compression and four foraminal lesions with central intraspinal (extradural) extension. There were 3 men and 13 women, ranging in age at the time of operation from 37 to 79 years. Three patients, of the six with intrathoracic tumours, were asymptomatic; the remaining 13 had preoperative symptoms ranging in duration from 3 weeks to 12 months (average, 9 months). Back pain with intercostal neuralgia was present in eight patients and neurologic signs were present in six patients. A routine chest radiograph was abnormal in 10 patients, and x-rays of the thoracic spine were abnormal in 4 of the other 6 patients. The tumour was excised surgically in all patients. Complications developed postoperatively in two patients: one had Horner's syndrome, transient paraparesis and bleeding; the other had a small subarachnoid-cutaneous fistula. The authors conclude that dumbbell neurogenic tumours and those causing vertebral-body destruction and collapse demand a multidisciplinary one-stage surgical approach. If the lesion is malignant and resection is not complete, radiotherapy or chemotherapy is necessary.


Colorectal leiomyosarcomas: a pathobiologic study with long-term follow-up.

Colorectal leiomyosarcoma (CLM) is an uncommon tumour. Reports of its occurrence have been published mostly as single cases or small series. This study documents 12 cases of CLM that were seen over a 28-year period in Saskatchewan. The annual incidence of CLM was 0.45 per million people and constituted 0.12% of all colorectal malignant tumours seen during the study period. CLMs had a predilection for the rectum and sigmoid and commonly were associated with rectal bleeding or abdominal pain. More than half the tumours were detected by sigmoidoscopy. A correct preoperative or intraoperative histologic diagnosis of leiomyosarcoma was made in only two out of six cases. A potentially curative surgical procedure was done in 10 of the 12 patients. The mean follow-up was 6.9 years. Eight patients had tumour recurrence or metastasis, or both. From the findings of this study the authors recommend wide excision of colorectal smooth-muscle tumours whenever there is a suggestion of malignancy.


Thoracoscopic transthoracic dorsal sympathectomy.

The authors report on the three patients who underwent thoracoscopic transthoracic dorsal sympathectomies by the techniques of minimal-access surgery learned from laparoscopic cholecystectomy. All three had histologic confirmation of removal of the sympathetic chain and have had an encouraging early postoperative result. The authors believe that thoracoscopic transthoracic dorsal sympathectomy can be accurately and safely performed and will become the method of choice for dorsal sympathectomy.


Prevention of herpes simplex virus infection by oral acyclovir after cardiac transplantation.

Infection with herpes simplex virus is common among immunosuppressed patients. In an attempt to prevent such infection, 58 patients (group 1) who underwent cardiac transplantation between 1987 and 1990 were given acyclovir (200 mg orally three times a day) prophylactically throughout their postoperative hospital stay (mean 22 days +/- 1 day). The patients' immunosuppressive protocol included cyclosporine, azathioprine and prednisone. The course of these patients was compared to that of 24 patients (group 2) who underwent cardiac transplantation between 1983 and 1986 but were not given prophylactic antiviral treatment postoperatively. The immunosuppressive protocol in these patients consisted of cyclosporine and prednisone. Herpes infection developed during the 1st year in 5 patients (9%) in group 1 and in 11 patients (46%) in group 2 (p < 0.05). The actuarial rates of freedom from herpes infection at 1, 6 and 12 months after transplantation were 100%, 98% +/- 2% and 95% +/- 3%, respectively, in group 1 and 82% +/- 7%, 58% +/- 11%, 53% +/- 11% in group 2. All viral infections were cutaneous or mucosal, except for one, which developed in a patient with pneumonia. All infections responded well to treatment, although one patient with an infected cornea was left with a permanent visual deficit. The authors conclude that prophylaxis of herpes simplex virus infection with acyclovir administered orally in the early postoperative period is effective in preventing viral infections during the 1st year after cardiac transplantation.


Unilateral versus bilateral thyroid resection in differentiated thyroid carcinoma.

Risk-group definitions have been developed recently in an attempt to clarify which operation to do for whom in differentiated thyroid carcinoma. The authors attempted to confirm the validity of an age-based risk-group definition for identifying patients at high risk of death from thyroid carcinoma and to test whether the degree of surgical resection in either high- or low-risk groups affected patient survival. An age-based risk-group definition was used in the retrospective analysis of 161 patients with differentiated thyroid carcinoma seen at the Saskatoon Cancer Centre, University of Saskatchewan, between 1933 and 1964. A significant difference was found in the death rate between low- and high-risk groups (4.3% versus 47% respectively). This confirms the validity of such an age-based risk-group definition. Although a long-term survival benefit was suggested with the use of bilateral thyroid resection in high-risk patients, the difference was not significant. In low-risk patients, there was no difference in the survival rate between patients who underwent unilateral or bilateral thyroid resection, followed up for as long as 55 years.


Management of papillary carcinoma arising in thyroglossal-duct anlage.

Cysts of the thyroglossal duct are common congenital abnormalities. They present as asymptomatic midline cervical swellings. The risk of malignant change is low; only 103 cases have been reported in the world literature, 85% of which were papillary adenocarcinomas. The appropriate treatment for this condition remains controversial. The authors describe three patients who had papillary carcinoma contained within a thyroglossal-duct rest. All were treated by cyst resection and thyroid suppression, but without thyroidectomy and radioactive thyroid ablation. Postoperatively, all patients remained disease free, with no recurrence at follow-up ranging from 10 to 29 years. Isolated papillary carcinomas arising from primitive thyroid remnants, associated with a palpably normal thyroid gland at surgery and a negative thyroid scan, can be treated adequately by excising the thyroglossal mass.


Nontertiary surgery in Manitoba: comparison of provincial and teaching-hospital data.

Do the teaching hospitals in Manitoba provide a suitable spectrum and sufficient numbers of operations to prepare surgeons for practice in Manitoban communities? To answer these questions, the author reviewed the types and frequencies of all operations performed in Manitoba during 1985 and 1986 and compared them with all operations performed in the two Manitoba teaching hospitals for the same years. The 189,380 operations studied were categorized according to the surgical specialist who usually performed each operation in the teaching hospitals. For some procedures commonly performed in the province as a whole, there were too few operations performed in the teaching hospitals to provide sufficient experience for the trainees. A breakdown of nontertiary operations performed in Manitoba revealed that 39% were in the category of general surgery, 29% were in gynecology and operative obstetrics, 17% were in orthopedics, 10% were in urology and 4% were in plastic surgery. The author concludes that a surgeon going to a smaller community as the only surgical specialist requires training of a broader scope than is provided currently in the standard general-surgery training programs in Manitoba.