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Biomedical subjects

G Thomson

Publications and source records attributed to G Thomson.

158 records · Page 9Linked to original sources
PubMed1979

HLA haplotype associations with disease.

Interest recently has extended to the problem of looking for HLA haplotype associations with particular diseases. Higher order interactions, that is to say of particular haplotypes with a disease, are much more complicated than individual antigen associations, with which most disease studies have so far been concerned. Our aim in this work is to explain the concept of higher order interactions and to discuss the difficulties involved when trying to measure such haplotype associations. The main emphasis is to point out that it is not easily possible to detect haplotype associations if an individual antigen association with the disease exists.

Alleles↗
PubMed1979

Genetic drift in sex-linked lethal disorders.

A model is considered to calculate effects of genetic drift on the expected proportion of new mutants amongst males affected by a sex-linked recessive lethal. We show how to relate the number of cases of the disorder in males to the expected deviations from the deterministic value of the proportion of new mutants. For small values of alpha (= 3N mu), where N is the size of the female population, and mu is the mutation rate from wild-type to lethal allele, the standard deviation (SD) of the proportion of new mutants is large. However, if alpha more than 50, the potential effect of genetic drift is probably less important than the many other sources of error and bias.

Gene Frequency↗
PubMed1977

Giant cell tumor of the sphenoid bone.

The clinical and histological features of two cases of giant cell tumor of the sphenoid bone are described. Both presented with similar symptoms and signs, comparable to previously described cases. The problems in histological differential diagnosis are discussed and radiotherapy as the treatment of choice is suggested.

Adolescent↗
PubMed1977

The effect of a selected locus on linked neutral loci.

The effects produced on linked neutral loci as a selected locus evolves towards its equilibrium value are considered. Significant effects on the neutral loci arise if the recombination fraction between the neutral and selected loci is smaller than the order of magnitude of the selective differences at the selected locus. The effect on gene frequencies at the neutral loci, that is, the hitchhiking effect, is determined, as well as the linkage disequilibrium generated by this hitchhiking effect. One of the more important findings is that significant disequilibrium can be generated between two neutral loci by the evolution of a linked selected locus. Consideration is given to the problem of determining how the effect of selection operating in natural populations can be detected, the question of the establishment of inversions in populations, and also to the nonequilibrium properties of populations.

Chromosome Inversion↗
PubMed1977

Properties of equilibria in multi-locus genetic systems.

The classical mathematical theory of population genetics considered, for simplicity, almost exclusively one-locus systems. In the last two decades much work has been done on two-locus and, less frequently, multi-locus systems. This research has usually involved investigating properties of systems with given, and usually rather special, fitness parameters. Real genetic fitness systems are undoubtedly multi-locus and seldom will possess simplifying characteristics. One aim of this paper is to study generalized systems where no special assumptions are made about fitness structure, the number of alleles at each locus, the number of loci involved or the recombination structure between loci. A second aim is to consider marginal properties (often one-locus properties) of complex systems: the fact that many observations involve data from only on locus makes this second aim relevant.

Alleles↗
PubMed1971

Caveat lector.

Explore the source record for details and available documents.

Letter↗
PubMedDate not supplied

Physiologic observations in a controlled clinical trial of the antiemetic effectiveness of 5, 10, and 15 mg of delta 9-tetrahydrocannabinol in cancer chemotherapy. Ophthalmologic implications.

One hundred twenty patients about to receive their first treatment with potentially nauseant cancer chemotherapy were randomized to one of six antiemetic treatments: (1) no treatment; (2) placebo; (3) prochlorperazine (PCPZ), 10 mg; (4) delta 9-tetrahydrocannabinol (THC), 5 mg; (5) THC, 10 mg; (6) THC, 15 mg. Four doses of each medication were given orally at 4-hour intervals starting 2 hours before chemotherapy. A study nurse was responsible for both objective (nurse) and subjective (patient) symptom questionnaires. Serum levels were obtained at intervals for cross-reacting cannabinoids. Physiologic measurements including intraocular pressure (IOP), blood pressure, and pulmonary function were also recorded. In summary, the patients were remarkably free of adverse physiologic effects. All intraocular pressures before and after treatment were within the normal range, although a surprising statistically significant increase in IOP occurred in the group receiving 5 mg THC.

Antineoplastic Agents↗
PubMedDate not supplied

Field observations on influenza vaccination among horses in Britain, 1971-1976.

The observations reported in this paper were obtained as part of a long term surveillance programme designed to monitor the efficacy of influenza vaccines and study the prevalence of influenza and other respiratory viruses among horses in Britain. Inactivated influenza vaccines were found to be effective in protecting horses from disease caused by influenza A/equine-1 but were less successful in protecting horses against influenza A/equine-2. The paper presents the clinical, epidemiological virological and serological findings obtained between 1971 and 1976.

Animals↗