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Biomedical subjects

C B Thomas

Publications and source records attributed to C B Thomas.

At least 55 records · Page 3Linked to original sources
PubMed1991

Familial and psychological predictors of cancer.

The hypothesis that the quality of human relationships is a component in the development of cancer was investigated in a prospective study of former medical students. Findings from two psychological measures are presented: the Closeness to Parents Scale, which showed that students who subsequently developed cancer were more likely to describe a lack of closeness with their parents than their healthy classmates; and the Rorschach Interaction Scale, which demonstrated less satisfactory relationships among male cancer victims as contrasted with the rest of the cohort. The findings suggest that internal self-other representations, as measured by these two tests, are involved as regulators of biologic systems and manifestations of illness, such as cancer.

Attitude↗
PubMed1990

Epizootiologic patterns of diabetes mellitus in cats: 333 cases (1980-1986).

Medical records from 333 cats with diabetes mellitus were studied retrospectively, using epidemiologic methods to determine the incidence of and risk factors for diabetes mellitus in this species. Abstracts were derived, using the Veterinary Medical Data Program with its 17 participating academic institutions in the United States and Canada. A reference population of 135,651 cats was derived from the same hospital population and time span (July 1980 to June 1986). The incidence of diabetes mellitus in cats was determined to be 2.45 cases/1,000 cat-years-of-risk during the 6-year study period. Breed had no detectable effect on risk for diabetes mellitus. In contrast, body weight, age, gender, and neutering had a significant (P less than or equal to 0.01) effect. Body weight of cats was categorized as being less than or greater than or equal to 6.8 kg. The higher body weight, probably indicating obesity, contributed a 2.2-fold increase in risk, even after adjustment for age and gender (adjusted odds ratio). The etiologic fraction for high body weight was 3.8%, suggesting that an estimated 3.8% of cases of diabetes mellitus was attributable to this factor alone. Over 50% of diabetic cats were greater than 10 years old, and the etiologic fraction for age greater than 7 years alone was 73.5%. Age was a significant (P less than 0.001) and the most important single risk factor for development of the disease in cats, with adjusted odds ratios of 8.3 and 14.4 for age 7 to 10 years and greater than 10 years, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Mycoplasma bovis suppression of bovine lymphocyte response to phytohemagglutinin.

The effect of viable Mycoplasma bovis on the in vitro bovine peripheral blood lymphocyte response to phytohemagglutinin (PHA) was studied. Results showed that M. bovis did not act as a mitogen for bovine lymphocytes. Viable M. bovis produced a dose and time dependent suppression of the PHA stimulated lymphocyte response. Suppression was not a result of differences in the viability of infected or control lymphocyte cultures. The suppressive effect of M. bovis was found to be independent of the concentration of PHA used in the test and the lymphocyte response could not be restored by supplementation of the culture medium with arginine. Delay for 48 h after PHA stimulation before adding M. bovis to the lymphocyte cultures diminished, but did not prevent, the suppression of the lymphocyte response. These results show that suppression of the lymphocyte response does not require the presence of M. bovis during the period of PHA stimulation, and that M. bovis was capable of interrupting [3H]-thymidine incorporation in lymphocytes which were actively synthesizing DNA.

Animals↗
PubMed1990

Evaluation of a commercial staphylococcal bacterin for management of idiopathic recurrent superficial pyoderma in dogs.

Twenty-one dogs with idiopathic superficial recurrent pyoderma were entered into a double-blind, placebo-controlled study to evaluate the efficacy of a commercial staphylococcal bacterin. The study spanned an 18-week period. All dogs were administered sodium oxacillin orally for the initial 6 weeks of the study. Dogs were given the bacterin or placebo SC, twice weekly at 3- or 4-day intervals, beginning at week 0 and continuing for 18 weeks. Dogs given antibiotics plus the bacterin (n = 13) had a significantly (P less than 0.05) better treatment response than those given antibiotic plus placebo.

Animals↗
PubMed1989

Ipsilateral sternoclavicular dislocation and clavicle fracture.

A case of ipsilateral distal clavicle fracture and sternoclavicular joint dislocation is reported. This combination of injuries results from two separate forces in sequence. Closed reduction of the dislocation was possible only after open reduction and internal fixation of the clavicle fracture was performed, because of the inability to manipulate the free-floating segment. Patients should be carefully examined for associated brachial plexus injuries.

Adult↗
PubMed1989

Cardiovascular reactivity to the cold pressor test as a predictor of hypertension.

Cardiovascular reactivity to stress is hypothesized to be a marker for subsequent neurogenic cardiovascular disease, but few prospective studies of this hypothesis are available. We studied 910 white male medical students who had their blood pressure and pulse rate measured before and during a cold pressor test in the years 1948-1964. Hypertensive status (requiring drug treatment) was ascertained by annual questionnaires in the 20- to 36-year follow-up period. An association was observed between maximum change in systolic blood pressure and later hypertension, with a cumulative incidence of hypertension by age 44 of 6.7%, 3.0%, and 2.4% for a change in systolic blood pressure in the upper, middle two, and lowest quartiles, respectively (Kaplan-Meier, p less than 0.02). After adjustment for study entry age, Quetelet Index, cigarette smoking, pretest systolic blood pressure, and paternal or maternal history of hypertension in a Cox model, the association persisted. The excess risk associated with systolic blood pressure reactivity was not apparent until the population aged some 20 years and was most apparent among those in whom hypertension developed before age 45 (relative risk = 2.5, 95% confidence intervals = 1.47, 4.71 for a 20 mm Hg change). Diastolic blood pressure and heart rate changes were not associated with later hypertension. These data suggest that persons prone to later hypertension manifest an altered physiology at a young age.

Adult↗
PubMed1988

Epidemiologic and immunologic evaluation of an outbreak of canine blastomycosis.

Five confirmed cases of canine blastomycosis occurred over the 10-month period of December 1983 to September 1984 in a south-eastern Wisconsin colony of 30 dogs maintained for sled competition. Contrary to other published reports of canine blastomycosis, the sex-specific attack rates were higher among females than males. Four of the five confirmed cases and all four deaths occurred among young female dogs. Differences in the age distribution and/or the micro-environment of the females may have contributed at least in part to the difference in sex-specific attack rates. The serologic response and leukocyte function of the clinically affected and apparently healthy dogs from this colony were assessed during the outbreak. A survey of the adult dogs in the colony suggested that the mitogen-induced lymphocyte blastogenesis of dogs with clinical signs of blastomycosis was suppressed compared with that of dogs that remained free of clinical signs. In contrast to previous reports that autologous sera from dogs and humans with clinical blastomycosis inhibited mitogen-induced lymphocyte blastogenesis, lymphocyte responsiveness was similar to, or greater in the presence of autologous canine serum than it was in the presence of fetal bovine serum.

Animals↗
PubMed1988

Immune responses to Mycoplasma bovis vaccination and experimental infection in the bovine mammary gland.

This study characterized the immune responses in four vaccinated and four control cows in response to vaccination and experimental intramammary inoculation with Mycoplasma bovis. Specific antibody responses occurred in serum and milk in response to vaccination and experimental infection. Lymphocytes from peripheral blood, but not from the mammary gland of vaccinated cows had increased responsiveness to mitogens. No lymphocytes tested were responsive to M. bovis antigen. Both vaccination and experimental infection resulted in skin test reactivity. These results imply that vaccination results in immune responses which may alter the course of experimental M. bovis mastitis, but may contribute to cellular inflammation.

Animals↗
PubMed1987

Precursors of hypertension in black compared to white medical students.

Data were collected on 433 black medical students at Meharry Medical College (MMC) and 573 white medical students at The Johns Hopkins University School of Medicine (JHMS) during the period of 1958 through 1965 consisting of baseline measurement of some possible precursors of hypertension. Similar methods were employed in both cohorts. Comparison as to prevalence and significance of hypertension precursors revealed the following: Black males had significantly higher casual and resting blood pressures than whites (p less than 0.01); and higher mean changes in blood pressure following the cold pressor test. White males had a significantly higher mean change in heart rate following cold pressor test (p less than 0.01). Upon exercise black males had significantly higher mean change in blood pressure and heart rate (p less than 0.01). There appears to be more blood pressure lability in blacks as indicated by higher mean SBP + DBP changes following the cold pressor test, and by mean pulse pressure level at peak exercise. The difference in blood pressure lability observed between blacks and whites in young adulthood may be one of the earliest identifiers of later differences in the incidence of hypertension. However, of even more importance is the difference in blood pressure levels between the two groups, though both are normotensive.

Adult↗
PubMed1987

Dementia of the Alzheimer type: clinical and family study of 22 twin pairs.

We studied 22 twin pairs in which one or both twins had dementia of the Alzheimer type (DAT). In four twins, diagnosis was confirmed by autopsy. Seven monozygotic (MZ) pairs were concordant for DAT; 10 MZ pairs were discordant. Two dizygotic (DZ) pairs were concordant for DAT, and 3 DZ pairs were discordant. The current concordance rate was 41% for MZ twins and 40% for DZ twins. The study supports the belief that, etiologically, DAT cannot be entirely accounted for by a single autosomal dominant gene. The data also suggest that in certain genetic circumstances, disease expression may be delayed in females.

Aged↗
PubMed1987

Pathogenesis of bovine mycoplasma mastitis.

Most bovine mastitis due to mycoplasmas is initiated by passage of mycoplasmas through the teat canal into the teat and gland cisterns. Within a few days, mycoplasma numbers increase to as much as 10(6) or 10(8), and the cows react with a strong inflammatory response. Alveolar epithelium undergoes degenerative changes and exudate replaces milk secretion. The interstitium between alveoli is invaded with lymphocytes, macrophages, plasma cells and fibroblasts. The extent and duration of these changes vary greatly. In milder cases, they may be reversed within days or weeks with a return to normal or reduced milk production. Often, destruction and atrophy of alveoli are complete with extensive fibrosis throughout the udder. Milk ducts may undergo invasive and obliterative fibrosis. Cell-mediated responses are suppressed, while hypersensitivity is suspected of enhancing the adverse responses. Immunity in cows that recover is variable and of limited duration.

Animals↗
PubMed1987

Experimental intramammary inoculation with Mycoplasma bovis in vaccinated and unvaccinated cows: effect on local and systemic antibody response.

Four cows were vaccinated with Mycoplasma bovis five times at two week intervals: three times subcutaneously in Freund's complete adjuvant, and two times with M. bovis alone in two of four quarters by intramammary infusion. The effect of vaccination on the immune response was evaluated in the serum and whey of the four vaccinated and control (placebo) cows experimentally challenged in two of four quarters with live M. bovis. Vaccination resulted in markedly increased M. bovis-specific, serum IgM, IgG and IgG2, but not IgA, reactivity. Challenge exposure with live M. bovis by intramammary infusion resulted in high specific serum IgM, IgG1 and IgG2 reactivity and a noticeable IgA response in both vaccinated and control cows. Whey from quarters on vaccinated cows had elevated, specific IgG1 reactivity at the time of challenge but no other differences were observed. Challenge exposure with live M. Bovis resulted in high antibody levels of all isotypes in quarters which were challenged, but highly elevated reactivities in unchallenged quarters occurred only with IgG1 and IgG2. These results indicate that vaccination elevated M. bovis-specific IgG1 but not other immunoglobulin reactivity in quarters on vaccinated cows, and that live organisms are necessary to elicit a local, specific IgA response.

Animals↗
PubMed1987

Enzyme-linked immunosorbent assay for detection of Mycoplasma californicum-specific antibody in bovine serum: optimization of assay determinants and control of serologic cross-reactions.

An enzyme-linked immunosorbent assay (ELISA) was adapted to detect Mycoplasma californicum-specific antibodies in bovine serum. Cross-reactive antibody was found in the M californicum-positive reference serum when assayed against each of 7 solid-phase antigens of heterologous mycoplasma species. Cross-reactivity was further demonstrated by inhibition of ELISA reactivity to M californicum solid-phase antigen by incubation of sera with antigen suspensions of each heterologous species. Incubation of test sera with a cross-reacting antigen mixture containing equal proportions of the 7 cross-reactive mycoplasmas was used to minimize cross-reactivity in the M californicum-specific ELISA. Specificity of antibody reactivity to M californicum, as measured by ELISA, was determined by enzyme-linked immunosorbance inhibition, in which sera were incubated with M californicum antigen suspensions before determining ELISA reactivity to M californicum solid-phase antigen. Seropositive and suspect sera (n = 55) were obtained from 3 dairies that had bacteriologically verified epizootics of M californicum mastitis. The percentage of inhibition demonstrated in enzyme-linked immunosorbance inhibition was determined for each serum. Inhibition percentages below the 15th percentile (61% inhibition) of this distribution were classified as nonspecific.

Animals↗
PubMed1987

Detection of bovine serum antibody specific to Mycoplasma bovis and Mycoplasma californicum by enzyme-linked immunosorbent assay (ELISA).

ELISA for use in epidemiologic field studies of bovine mastitis, were developed to measure serum antibody to Mycoplasma bovis and M. californicum. Varying levels of serological cross-reactivity to seven heterologous bovine mycoplasmal species were demonstrated in each assay. Cross-reactivity was minimized by preincubation of cattle sera with suspensions of heterologous mycoplasma antigens, prior to measuring serum antibody to solid-phase antigen. Heterologous absorption improved the immunological specificity of the assays while avoiding the need to prepare species-unique antigens. Serum antibody was measured at one serum dilution. Test results were expressed as a ratio of the reactivity of a positive and a negative reference serum. A negative reference population (n = 127) was assembled. The percentile distribution of ELISA reactivity of these 127 sera were used to establish the classification criteria for each assay. The statistical methods used, while easily applied, were found to be sensitive to outlying values in the reference population. The resulting classification criteria provided controlled or known probabilities of false-positive misclassification in the two ELISA test systems. Sera from cattle with defined exposure histories were tested and classified according to these criteria.

Animals↗
PubMed1986

Coffee consumption and the incidence of coronary heart disease.

We conducted a prospective investigation of the effect of coffee consumption on coronary heart disease in 1130 male medical students who were followed for 19 to 35 years. Changes in coffee consumption and cigarette smoking during follow-up were examined in relation to the incidence of clinically evident coronary disease in comparisons of three measures of coffee intake--base-line intake, average intake, and most recent intake reported before the manifestation of coronary disease. Clinical evidence of coronary disease included myocardial infarction, angina, and sudden cardiac death. In separate analyses for each measure of coffee intake, the relative risks for men drinking five or more cups of coffee per day, as compared with nondrinkers, were approximately 2.80 for all three measures in the univariate analyses (maximum width of 95 percent confidence intervals, 1.27 to 6.51). After adjustment for age, current smoking, hypertension status, and base-line level of serum cholesterol, the estimated relative risk for men drinking five or more cups of coffee per day (using the most recent coffee intake measure), as compared with those drinking none, was 2.49 (maximum width of 95 percent confidence interval, 1.08 to 5.77). The association between coffee and coronary disease was strongest when the time between the reports of coffee intake and the coronary event was shortest. These findings support an independent, dose-responsive association of coffee consumption with clinically evident coronary heart disease, which is consistent with a twofold to threefold elevation in risk among heavy coffee drinkers.

Adult↗
PubMed1986

A possible relationship between figure drawing data collected in medical school and later health status among physicians.

Figure drawings obtained while subjects were in medical school were scored using two different scales: (a) Sophistication-of-Body-Concept, a scoring system that measures the overall quality of the drawings; and (b) Conventionality/deviancy of the drawings, as determined by the relative frequency with which 42 different characteristics occurred in the total sample of drawings. Figure drawings were obtained from 1951 to 1964. As of 1984, subjects were classified into 1 of 11 health outcome (disease) categories plus a "healthy" category. Statistical analysis included one-way analyses of variance and multiple logistic regression in which age and cigarette consumption were controlled. Several statistically significant differences among groups were noted with respect to Conventionality/deviancy, but not with respect to Sophistication-of-Body-Concept.

Adult↗
PubMed1986

Thermotaxis in third and fourth-stage Dirofilaria immitis larvae.

Third-stage and fourth-stage Dirofilaria immitis larvae exhibited positive thermotaxis when placed in a thermal gradient. Negative thermotaxis was not observed. Positive thermotaxis may be important for the successful transmission and for directing third and fourth-stage larval migration toward predilection sites in the host.

Aedes↗