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Biomedical subjects

S Brown

Publications and source records attributed to S Brown.

At least 631 records · Page 35Linked to original sources
PubMed1985

Renal oncocytoma followed for eighteen years without resection.

The natural history of unresected renal oncocytomas is unknown. We report a renal oncocytoma which was mistakenly diagnosed as benign renal cyst and followed up for eighteen years. We are unable to find other oncocytomas without resection which were followed up. The apparent lack of change in size over eighteen years supports the concept of slow growth. Malignant histologic characteristics confirm the potential for malignant degeneration in what is generally considered to be a benign lesion.

Adenoma↗
PubMed1985

Desiccation resistance and contamination as mechanisms of gaia.

The gaia hypothesis, formulated by J.E. Lovelock, asserts the composition of the reactive gases, the oxidation-reduction state and the temperature of the lower atmosphere of the planet Earth are actively regulated by the biota. Lovelock and Watson, using highly simplified mathematical models, have shown that the modulation of atmospheric temperature can be achieved by exponentially growing populations of differently colored organisms ("dark and light daisies"). It is more likely that the modulation of atmospheric gas composition is based on the colligative properties of exponentially growing mixed populations of microorganisms rather than on "daisies". Exponential growth of one population of microorganisms leads to gaseous and other metabolic products released to the environment, which favor the exponential growth of different populations, each with their own unique emissions. Extremely high densities of mixed populations of microorganisms ensue. These populations form structured microbial communities composed of members in varying states of activity. Growth potential of metabolically diverse populations most likely provides the basis for the responsiveness of the biota to changing environments. We have attempted to measure an aspect of the growth potential and diversity of one microbial community, that from a flat laminated microbial mat dominated by the cyanobacterium, Microcoleus. Microbial mat samples collected at yearly intervals between 1977 and 1982 were allowed to dry. Subsamples were revived under laboratory conditions by rewetting, and the resulting complex microbial populations were analyzed. Greater than 10(4) viable organisms per ml were estimated to be present in the desiccated samples. Only a portion of the diverse community could be characterized. There were at least 115 different types of desiccation resistant microorganisms present in these samples, primarily bacteria. However, more than a dozen types of rather uncommon fungi and protoctists were removed from naturally desiccated material. Several did not fit descriptions of previously known species or strains. Neither animals nor plants were recovered from these tiny samples. We present minimal diversity estimates for microorganisms in both the desiccated samples and the corresponding fresh laminated microbial mat community from which they were taken. We found that many organisms in laboratory samples capable of immediate growth from a desiccated state were not common components of growing mats in the field.(ABSTRACT TRUNCATED AT 400 WORDS)

Atmosphere↗
PubMed1985

Treating gonococcal infections resistant to penicillin in Bangkok: comparison of cefuroxime and spectinomycin.

Gonococcal organisms have become resistant to antimicrobials throughout the world. Such resistance is common in Thailand, where 40% of gonococci produce penicillinase (PPNG strains) and over half the remainder have MICs of penicillin greater than or equal to 1 mg/l. To evaluate the effectiveness of cefuroxime against such resistant organisms, a controlled clinical trial comparing spectinomycin and cefuroxime was conducted at Bangrak Hospital, Bangkok, in 1982-3. Of 472 patients who were randomly assigned to treatment, 365 (77%) yielded positive cultures before treatment and returned for follow up evaluation three to 13 days after treatment. Of the 365 patients, 359 (98%) were cured, and no difference between the two treatment regimens was found either by the sex of the patient or by the presence of PPNG strains. The MIC of cefuroxime against all organisms was less than or equal to 1 mg/l. In vitro susceptibilities of gonococci in Bangkok have not changed appreciably during the past two years. Regimens of cefuroxime and spectinomycin are highly effective even for the relatively resistant gonococci in Bangkok. The pharmacokinetics, in vitro susceptibilities, and effectiveness of cefuroxime encourage evaluation of lower doses of the drug.

Adolescent↗
PubMed1985

Cost-effective selection of fire fighter recruits.

To discriminate suitable fire fighters from recurring large groups of applicants, an objective test battery was developed which screened applicants on the basis of physical, psychomotor, and mental abilities. The physical and psychomotor selection procedures first involved fundamental tests of general aerobic endurance, upper body strength, and anaerobic endurance. Successful candidates progressed to more specific tests. Measurements were made of height, weight, hamstring flexibility, balance, strength, upper body flexibility, hand-eye coordination, and the ability to negotiate a fire fighting simulation course. Results of these tests were weighted, allocating 25% to physical tests, 20% to psychomotor tests, and 39% to the simulation course. These scores were then combined with scores of several knowledge tests weighted to be 16% of the whole. This provided a computer-generated ability profile of the top applicants which was considered at their interview before a final selection board of fire service officers. Selected candidates were then required to pass a medical examination. Pearson correlation coefficient analysis of 1984 test results demonstrated general independence of the tests (R = -0.34 to R = 0.52), with the exception of bilateral grip strength (R = 0.77). The first four trials of the selection procedure screened 3,172 applicants, 16.4% of whom were finally selected for interview. City officials estimated that based on a comparison of new and previously used selection procedures, cost savings of +92,500 were being achieved by 1984.

British Columbia↗
PubMed1985

A comparison of the nutrient intake of some Scotsmen with dietary recommendations.

During 1980 and 1982, 164 men aged 45-54 in North Edinburgh and West Fife participated in a 7-day individual weighed dietary survey. The mean energy intake was 11.2 MJ (2700 kcal), 38.1 per cent of which came from fat and 6.7 per cent from alcohol. The P:S ratio was 0.30 and the mean daily fibre intake 19.8 g. Saturated fatty acids accounted for 16.3 per cent of the energy and polyunsaturated fatty acid for 4.6 per cent. Oleic acid was the principal dietary fatty acid accounting for 32.4 per cent of fatty acids. The major polyunsaturated fatty acid was linoleic acid and contributed 3.5 per cent of energy. Cereal and cereal products were the principal source (30.8 per cent) of linoleic acid. Though this study was conducted prior to the publication of recent dietary recommendations, a small proportion of the men were achieving some of them but few would have met the recommendations in full.

Animals↗
PubMed1985

Emission tomography: its contribution in the detection of subdural haematoma.

The technique of emission computed tomography (ECT) was assessed with regards to its value in the detection of subdural haematoma. Results from an anthropomorphic head phantom and a short clinical trial both showed promising signs of better differentiation between normal and abnormal in equivocal results. A simple quantitative index was used to compare ECT with static imaging. The conclusion is that ECT is of value in those patients whose scan results are otherwise equivocal.

False Negative Reactions↗
PubMed1985

Cell interactions in preimplantation embryos: evidence for involvement of saccharides of the poly-N-acetyllactosamine series.

Roles of cell surface carbohydrates containing the 3-fucosyl-N-acetyllactosamine and poly-N-acetyllactosamine sequences (SSEA-1 and I antigens, respectively) in the compaction of mouse embryos have been investigated using the endo-beta-galactosidase of Bacteroides fragilis to modify the surface of cleavage-stage embryos. Treatment with this enzyme abolished SSEA-1 activity and diminished I antigen activity on the embryonic cell surface. Embryos cultured in the presence of endo-beta-galactosidase from the 2- to 4-cell stage onwards, or treated with the enzyme at the compacting 8-cell stage, continued to compact and proceeded to form blastocysts at the normal rate. However, when compacted 8- to 16-cell embryos were experimentally decompacted in calcium-free medium, treated for 1 h with endo-beta-galactosidase and returned to normal culture medium, the time taken for 50% of the embryos to recompact was prolonged five-fold. There was an even greater delay if these embryos were maintained in culture medium containing the enzyme. Blastocysts were eventually formed under both conditions. Thus, endo-beta-galactosidase did not affect compaction unless the embryos were first decompacted. On the assumption that recompaction and de novo compaction occur by similar mechanisms, we propose that carbohydrate-binding molecules are involved which have high affinities for poly-N-acetyllactosamine structures and protect them from digestion by endo-beta-galactosidase.

Animals↗
PubMed1985

Transplantation of amniotic epithelial membranes in patients with mucopolysaccharidoses.

This paper reports the biochemical results of transplanting human amniotic epithelial cells in 3 children with Hunter's and 2 with Hurler's disease. A transient and modest increase of alpha-L-idurono-2-sulphate sulphatase or alpha-iduronidase was observed in the white cells collected from 1 patient with Hunter's and 1 with Hurler's disease. No variation in the excretion of glycosaminoglycans or oligosaccharides was detected in all 5 patients. There was no evidence of immune response towards the transplanted cells or the specifically deficient enzyme. Thus, in spite of the absence of the major histocompatibility antigens, HLA A, B, C and DR, on the surface of the amniotic epithelial cells, no long-term correction of lysosomal enzyme deficiencies was achieved by transplanting amniotic epithelial membranes collected at the end of the gestational period.

Amnion↗
PubMed1984

The 4.5 S RNA gene of Escherichia coli is essential for cell growth.

The Escherichia coli gene coding for the metabolically stable 4.5 S RNA (ffs) has been shown to be required for cell viability. Essentiality was demonstrated by examining the recombination behavior of substitution mutations of ffs generated in vitro. Substitution mutants of ffs are able to replace the chromosomal allele only in the presence of a second, intact copy of ffs. Independent evidence of essentiality and the finding that 4.5 S RNA is important for protein synthetic activity came from characterization of cells dependent on the lac operon inducer isopropyl-beta-D-thiogalactoside for ffs gene expression. Here, a strain dependent on isopropyl-beta-D-thiogalactoside for 4.5 S RNA synthesis was developed by inactivation of the chromosomal ffs allele and lysogenization by a lambda phage containing 4.5 S DNA fused to a hybrid trp-lac promoter. Withdrawal of the thiogalactoside leads to a deficiency in 4.5 S RNA, a dramatic loss in protein synthesis activity, and eventual cell death. Tagging of the chromosomal ffs region with a kanamycin-resistance gene allowed mapping of the 4.5 S RNA gene. Results from this analysis place ffs near lon at approximately ten minutes on the E. coli linkage map.

Bacterial Proteins↗
PubMed1984

Schneider's first-rank symptoms of schizophrenia. An association with increased growth hormone response to apomorphine.

Growth hormone and prolactin (PRL) responses to 0.75 mg of apomorphine hydrochloride were measured in 19 newly admitted psychotic patients who had been untreated by neuroleptic or antidepressant drugs for at least nine months. We compared hormonal responses between subgroups of patients who were distinguished using the diagnostic criteria of Feighner et al and Spitzer et al, and by the presence or absence of Schneider's first-rank symptoms of schizophrenia. We included nine healthy subjects who were matched by age and sex with the schizophrenic patients. Growth hormone responses to apomorphine were greater in patients with Schneider's first-rank symptoms than in those without first-rank symptoms, and were also greater than in control subjects. Suppression of plasma PRL was also greater in schizophrenic patients than in control subjects. These results support the dopamine hypothesis of schizophrenia.

Acute Disease↗