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Biomedical subjects

S Findlay

Publications and source records attributed to S Findlay.

At least 109 records · Page 6Linked to original sources
PubMed1991

Inorganic phosphorus stimulation of bacterioplankton production in a meso-eutrophic lake.

Experiments were conducted to determine whether production of heterotrophic bacterioplankton in a small meso-eutrophic lake was influenced by the dissolved inorganic phosphorus (DIP) supply. DIP may indirectly limit bacterial production by limiting phytoplankton, which in turn may limit the carbon available to bacteria. Direct DIP limitation of bacteria occurs where the availability of DIP for bacteria is insufficient to maintain growth. This work examined direct DIP limitation of bacteria by removing phytoplankton and incubating flasks with or without added P in the dark. Bacterial production was measured via the rate of incorporation of [H]thymidine ([H]TdR) into DNA. Bacterial abundance was followed with epifluorescent direct counts. Rates of [H]TdR incorporation were significantly greater in flasks with added DIP, and changes in cell abundances generally paralleled increases in [H]TdR incorporation. Even very small additions of P (0.05 muM) were sufficient to stimulate production. DIP addition to whole lakewater also stimulated [H]TdR incorporation relative to that in zero-addition controls, but there was not a concurrent increase in bacterial cell numbers. The stimulation of [H]TdR incorporation after DIP addition to whole lakewater was significantly less than the stimulation due to DIP addition to 1-mum-pore-size-filtered lakewater. In this study, addition of DIP caused as much as an eightfold stimulation of [H]TdR incorporation.

Journal Article↗
PubMed1991

Pentigetide nasal solution: a multicenter study evaluating efficacy and safety in patients with seasonal allergic rhinitis.

The safety and efficacy of pentigetide (Pentyde) nasal solution, administered as 1 mg into each nostril four times daily, was compared with placebo for controlling symptoms associated with seasonal allergic rhinitis. This was a randomized, multicenter, double-blind, parallel-group trial involving 431 patients divided equally between pentigetide and placebo treatment. The study was conducted during the 1986 spring allergy season and consisted of 1 week of baseline followed by 2 weeks of treatment. Physicians evaluated the frequency and severity of nasal symptoms at study entry (day 1) and the final visit (day 22). Physicians and patients assessed the global condition of the patient at the end of the study and patients also recorded the severity of symptoms in a daily diary. Pentigetide-treated patients showed a statistically significant greater reduction in the frequency (P = .004) and severity (P = .05) of total nasal symptom score (sneezing, nasal congestion, and rhinorrhea) and in the individual nasal symptom scores compared with placebo-treated patients. Diary results showed consistently lower total nasal symptom scores on each treatment day for pentigetide-treated patients (P = .02). Both the physicians and patients globally rated more pentigetide-treated patients improved than placebo-treated patients. The incidence and types of adverse experiences were similar between treatment groups and there were no reports of sedation or fatigue in the pentigetide group. No clinically significant changes occurred for laboratory tests, physical examination parameters or vital sign measurements. Pentigetide nasal solution was safe and effective for the treatment of seasonal allergic rhinitis.

Administration, Intranasal↗
PubMed1991

Once daily triamcinolone acetonide nasal spray is effective for the treatment of perennial allergic rhinitis.

A randomized, double-blind, placebo-controlled, parallel group study was conducted in 11 centers to evaluate the safety and efficacy of a once-a-day regimen of 110 micrograms, 220 micrograms; and 440 micrograms of triamcinolone acetonide intranasal aerosol versus placebo in relieving the symptoms of rhinitis in 305 adult and older pediatric patients with perennial allergic rhinitis. Nasal stuffiness, nasal discharge, sneezing, nasal itching and the nasal index (the sum of the mean scores of the first three symptoms) averaged over the first 6 weeks and second 6 weeks of the study were significantly reduced in patients who received the 220 micrograms/day and the 440 micrograms/day dosages. The 110 micrograms/day group had a reduction in these nasal symptoms, but only the sneezing and nasal index were significantly (P less than .05) better than placebo. During the last 6 weeks of the study, patients were allowed to take oral back-up medication for their nasal symptoms; all three groups receiving triamcinolone nasal aerosol took less back-up medication than did the placebo group. There were no significant adverse effects or laboratory abnormalities noted during this study. Intranasal triamcinolone acetonide 220 micrograms and 440 micrograms, used once-a-day for 12 weeks is clinically and statistically superior to placebo for the treatment of perennial allergic rhinitis.

Administration, Intranasal↗
PubMed1990

Computer experiments on the evolution of sex: the haploid case.

We have conducted a set of computer experiments that investigate the conditions under which sexual reproduction can evolve. In these experiments, haploid genomes are treated as integer strings able to undergo mutation and, in the case of sexual strings, recombination, with string sequence (the genotype) determining fitness. Our results indicate that the likelihood of a rare sexual mutant spreading through an otherwise asexual population is small when sexual reproduction entails the classical two-fold cost of males. However, our results indicate that when mutation rates are not excessively high, sexual reproduction constitutes a more efficient fitness optimization algorithm, allowing a sexual population to adapt more quickly to its environment than an asexual population.

Animals↗
PubMed1990

America's best hospitals. Exclusive survey.

To identify the nation's best hospitals, U.S. news surveyed in 12 specialties from aids to urology. The survey yielded 57 different hospitals, many of which appear on more than one of the 12 specialty lists. The following hospitals, all of which found their way onto at least four of the lists, represent the cream of America's medical institutions.

Attitude of Health Personnel↗
PubMed1990

Fundamental theorem of natural selection in biocultural populations.

I derive a general equation for the evolution of mean biological fitness in large, randomly mating populations in which the phenotype is subject to both biological and cultural transmission and in which fitness and the effects of cultural transmission are genotype-dependent. The equation is dm/dt = 2 Cov(m,m'), where dm/dt is the instantaneous rate of change in the mean biological fitness of the population and Cov(m, m') is the covariance between offspring and parental fitnesses. This formulation differs from Fisher's fundamental theorem in at least two important respects. First, because covariances can be either positive or negative, mean fitness can decline over evolutionary time, in contrast to Fisher's result that fitness always increases. Second, since Cov(m, m') is a phenotypic rather than a genotypic covariance, natural selection can bring about changes in mean fitness even in the absence of additive genetic variance for fitness. Comparison of simple models of vertical (from parents to offspring) and oblique (from members of the parental generation to offspring) cultural transmission indicates that in the former case, mean fitness can evolve in the absence of genotypic variation for both fitness and the effects of cultural transmission, while in the latter case, both are required for evolution to occur.

Adaptation, Physiological↗
PubMed1984

Anaphylaxis in mast cell-deficient mice.

Evidence of a functional deficit in mast cell-deficient mice was sought by testing for the development of systemic anaphylaxis. W/Wv mast cell-deficient mice and wild type control animals were sensitized by injection of bovine serum albumin and subsequently challenged. Nine of ten W/Wv mast cell-deficient mice and 10/10 control mice demonstrated signs of anaphylaxis, including death. Although histamine levels were higher in control animals, no differences were noted before and after antigen challenge. The numbers of peripheral blood basophils were the same in W/Wv and wild type mice. These studies suggest that caution is necessary in the use of these animals to study disease.

Anaphylaxis↗