Search PubMed⌕ Search

Biomedical subjects

C B Thomas

Publications and source records attributed to C B Thomas.

At least 73 records · Page 4Linked to original sources
PubMed1986

Experimental intramammary inoculation with Mycoplasma bovis in vaccinated and unvaccinated cows: effect on the mycoplasmal infection and cellular inflammatory response.

The effect of vaccination on mycoplasmal infection and the cellular inflammatory response was evaluated in 4 vaccinated and 4 control cows experimentally challenged in 2 of 4 quarters with live Mycoplasma bovis. In unchallenged quarters during the first three weeks after experimental challenge exposure, 6 of 8 quarters on control cows, and 7 of 8 quarters on vaccinated cows became infected with low numbers (10(2)-10(4) cfu/ml) of M bovis. During the same period all challenge-infused quarters on both control and vaccinated animals became infected with high numbers (10(9) cfu/ml) of M bovis. Thereafter, all quarters on vaccinated cows became culture-negative for M bovis, while 2 of 8 unchallenged quarters, and 4 of 8 challenged quarters on 3 of 4 control cows remained infected. A cellular inflammatory response as measured by the California Mastitis Test accompanied the experimental infection in proportion to the infection level except in challenged quarters on vaccinated cows after the first three weeks post challenge in which the cellular inflammatory response remained high despite the advent of negative M bovis culture results. This study indicates that the course of experimental M bovis mastitis can be affected by vaccination, and that vaccination results in an adverse cellular inflammatory response in challenged quarters.

Animals↗
PubMed1986

Experimental intramammary inoculation with Mycoplasma bovis in vaccinated and unvaccinated cows: effect on milk production and milk quality.

The effect of vaccination on milk production was evaluated in vaccinated and control cows experimentally challenged in two of four quarters with live Mycoplasma bovis. During the first three weeks after experimental challenge, six of eight unchallenged quarters on vaccinated cows and seven of eight unchallenged quarters on control cows became infected. Most of these quarters secreted normal milk, with negative California Mastitis Test scores and maintained normal milk production throughout most of the study (although some quarters on control cows remained infected). All challenged quarters became infected, had strong California Mastitis Test reactions, and had a drastic (greater than 85%) loss in milk production. Thereafter, four of eight challenged quarters on control cows remained infected, had mostly positive California Mastitis Test scores, produced mostly normal-appearing milk, and recovered some productive capabilities. By the end of the study no M. bovis could be recovered from challenged quarters on vaccinated cows and the milk appeared mostly normal. The California Mastitis Test scores on these quarters, however, remained elevated and milk production remained very low.

Animals↗
PubMed1986

Canine Dirofilaria immitis infection in a hyperenzootic area: examination by parasitologic findings at necropsy and by two serodiagnostic methods.

A total of 174 dogs from an area hyperenzootic for Dirofilaria immitis were grouped into 4 age categories and necropsied; information was obtained on adult D immitis infections and on the presence of microfilariae. Serum samples from these dogs were examined by an enzyme-linked immunosorbent assay (ELISA) for antibody to adult D immitis and by an indirect fluorescent antibody test (IFAT) for antibody to microfilarial surface antigens. In dogs less than or equal to 5 months of age, necropsy demonstrated no evidence of infection; however, positive serologic results indicated that some of these dogs had prepatent infections. The percentage of dogs with ELISA titers (positive) increased with age, as did the percentage of dogs with adult D immitis infections. The IFAT results were positive in some dogs in each age category. Sera from all 29 dogs with occult infections were positive by ELISA. Sera from 6 of 20 dogs with occult dual-sex heartworm infections and 1 of 9 dogs with occult single-sex heartworm infections were positive by IFAT. For diagnosing occult dirofilariasis, the ELISA had a positive predictive value which increased with age of the dog to a maximum of 65.0% in dogs greater than or equal to 12 months of age; ELISA had a negative predictive value of 100% in all age groups. In contrast, positive and negative predictive values for the IFAT decreased with age of the dog to 60% and 37.5%, respectively, in dogs greater than or equal to 12 months of age.

Aging↗
PubMed1985

Correlates of midlife career achievement among women physicians.

In the context of a longitudinal study, we explored factors contributing to midlife career achievement among 108 women physicians. Three groups were formed, based on medical specialty, specialty board certification, and professorial appointment. Using analysis of variance procedures, the career groups were compared on measures obtained during medical school and on marital status, family size, and three health measures in midlife. Of the youthful measures, academic standing, father's socioeconomic status, and early family (specifically father-daughter) relationships were found to be associated with midlife achievement. Furthermore, a clear association was observed between success and good health in midlife. Married women formed the majority in all groups; no differences in family size were found. We conclude that career achievement among women physicians is influenced less by marriage and family size than by motivational and personality factors shaped in early life.

Achievement↗
PubMed1985

Characterization of monoclonal antibodies to bromodeoxyuridine.

The characteristics of three mouse monoclonal antibodies to halogenated uridine derivatives are presented. Two, IU-1 and IU-2, are produced by hybridomas derived in our laboratory, and the third is the B-44 hybridoma described by Gratzner (7) and obtained commercially from Becton-Dickinson Monoclonal Center. Hybridomas IU-1 and IU-2 were derived from the fusion of spleen cells from a Biozzi High Responder mouse immunized with iododeoxyuridine (IdUrd) conjugated to bovine serum albumin and SP2/0 mouse myeloma cells. This paper presents methods and results for enzyme-linked immunosorbent assays (ELISA) against whole cells labeled with bromodeoxyuridine (BrdUrd), ELISA against BrdUrd-labeled DNA, and a competition ELISA for free BrdUrd. All three antibodies show similar binding affinities and specificities. The IU antibodies react with BrdUrd and IdUrd when the nucleosides are either free in solution or incorporated into single-stranded DNA (ss-DNA). The antibodies do not recognize either halogenated base in double-stranded DNA (ds-DNA), nor do they react with uracil or bromocytidine. Weak binding to thymidine, 5-fluorodeoxyuridine, and unsubstituted ss-DNA occurs.

Animals↗
PubMed1985

Estimation of quantitative proteinuria in the dog, using the urine protein-to-creatinine ratio from a random, voided sample.

The correlation between 24-hour urine protein excretion and the protein-to-creatinine ratio (U-P/C) from random, voided urine specimens was assessed in 16 healthy Beagles (9 to 11 months old) and in 14 dogs with suspected renal proteinuria. Initially, a voided urine specimen was obtained from each dog, and the U-P/C was determined. An attempt was not made to standardize the time of collection of the voided urine. Subsequently, each dog was placed in a metabolism cage, and 24-hour urine specimens were collected for quantitative protein analysis. The Coomassie blue technique was used to measure urine protein. The correlation between the U-P/C and the 24-hour urine protein excretion (mg/kg/24 hr), evaluated by linear-regression analysis, was found to be significant (r = 0.975, P less than 0.01). These results substantiate previous findings and indicate that random, voided urine specimens may be used to compute the ratio and to accurately reflect 24-hour urinary protein loss in the dog.

Animals↗
PubMed1984

The oxidation of some polysaccharides by the hydroxyl radical: an e.s.r. investigation.

E.s.r. Experiments employing a flow system in conjunction with the TiIII-H2O2 couple show that dextrans react with the hydroxyl radical (HO.) via indiscriminate attack (except that abstraction of hydrogen atoms from carbons which are both linked by glycosidic bonds and included in the pyranose ring may be inhibited, possibly for steric reasons). Acid- and base-catalysed transformations of first-formed radicals have been demonstrated; the suggestion that such reactions can lead to glycosidic cleavage is supported by viscosity studies which confirm the pH-dependence of radical-initiated degradation. For galacturonan and related compounds, e.s.r. results indicate that reaction with HO. proceeds preferentially via abstraction of the hydrogen on the carbon adjacent to the carboxyl group. The crucial step in the subsequent degradation pathway probably involves a pH-independent rearrangement.

Dextrans↗
PubMed1984

Abetalipoproteinemia and metastatic spinal cord glioblastoma.

Abetalipoproteinemia (ABL [Bassen-Kornzweig syndrome]) is characterized by marked hypolipidemia with absence of low-density lipoproteins, fat-soluble vitamin deficiency, spinocerebellar ataxia, and retinitis pigmentosa. Our patient had ABL, severe neurologic disease, and spinal cord malignancy, as well as disseminated CNS and extraneural metastases. It is possible that patients with this disorder and long-standing fat-soluble vitamin deficiency may have increased risk for CNS malignancy.

Abetalipoproteinemia↗
PubMed1984

A comparison of three methods for scoring figure drawings.

Figure drawings obtained from 758 white male medical students were scored using three different methods. Method I involved 16 different physical size measurements; Method II involved six separate sophistication of body concept ratings; and Method III involved 42 separate aspects of the drawings weighted in direct proportion to their relative frequency of occurrence in the sample studied (conventionality scoring). Separate factor analyses of the scores derived from each method revealed that Methods I and II each reflect only a single underlying factor, and that these factors are uncorrelated in the population studied. Method III yielded eight meaningful factors, each of which may be construed as an independent area of conventionality/deviancy. An overall conventionality/deviancy score was also derived. It is believed that these three methods of scoring capture most of the variance inherent in existing figure drawing scoring systems, but that use of all three is necessary for a comprehensive analysis.

Factor Analysis, Statistical↗
PubMed1983

A multivariate analysis of circulatory data and their relationship to later disease.

Measurements on 21 separate variables involving blood pressure and heart rate were obtained under casual, resting, and controlled conditions as part of the baseline evaluation of 1087 white males participating in a prospective investigation of possible precursors of premature disease and death. These measurements were subjected to a components-type factor analysis with orthogonal rotation of component vectors in an effort to construct statistically independent composites of greater predictive power and generality as well as to minimize problems in interpretation introduced by partially redundant variables. Multivariate and univariate techniques were afterwards used to test differences between groups of subjects who developed specific major disorders and those who remained in good health. Comparison of factor scores with original circulatory measures in a series of prospective analyses revealed that the former had the greater predictive power. Although only the hypertension group could be unequivocally differentiated from all others, a number of nominally-significant findings may provide leads for further research.

Adult↗
PubMed1983

Prevalence of mycoplasmas and immune responses to Mycoplasma bovis in feedlot calves.

Microbiological cultural, cytologic, and immunologic observations were made on 30 calves. The eyes, nares, and bronchioalveolar region were subjected to microbiological cultural examination for mycoplasmas. Four of the examinations of 30 eyes, 15 of those of 30 nasal tissues, and 25 of those of the 30 bronchioalveolar regions from the 30 calves were positive for mycoplasmas. Mycoplasma bovis and M bovirhinis were the most prevalent species. Cytologic examinations of peripheral blood and bronchioalveolar washes did not show pathologic changes. Results of indirect hemagglutination, enzyme-linked immunosorbent assay, lymphocyte-stimulation tests on peripheral blood cells, and skin testing demonstrated only a low prevalence of immune recognition of M bovis. Infection and immune response were studied in 3 calves for 10 weeks before, and for 4 weeks after, intratracheal administration of live M bovis.

Animals↗
PubMed1982

Youthful habits of work and recreation and later cancer among physicians.

Scores on seven factors derived from a Habits of Work and Recreation Survey administered to 1,038 white male medical students 17 to 35 years ago were used to compare students who subsequently developed some form of major cancer with those who did not. With the Type I error rate controlled through use of multivariate analysis of variance and age and smoking ruled out as possible confounding variables, the two groups were significantly differentiated, primarily in terms of intellectual interests--cancer cases having fewer. Students at or below the overall mean on the intellectual interests measure were more than three times as likely to develop cancer as were students with scores above the mean. In this population, the results appear interpretable in terms of the stamina concept, in which few intellectual interests may reflect an absence of stamina and spontaneity and/or failure to meet subcultural expectations--factors possibly associated with increased cancer risk.

Adolescent↗
PubMed1982

Family attitudes in youth as a possible precursor of cancer among physicians: a search for explanatory mechanisms.

A measure of youthful family attitudes, the Closeness to Parents Scale, has continued to be predictive of cancer among physicians in a prospective study of medical students. Nonetheless, questions have remained concerning the meaning and reliability of this measure and whether its predictive value is diminishing over time. Perhaps more important, it is necessary to ascertain whether the relationship is the result of some methodological artifact or whether it is mediated by an association with known risk factors, such as smoking, drinking, and radiation exposure. Each of these issues was examined in turn, using a variety of statistical techniques to refine the scale and to equate cancer and control groups with respect to risk factors as well as possible artifacts. In a group of 913 men, it was found that the scale is primarily a function of good father-son relationships and that its association with later cancer persists even after the influence of possible mediating and artifactual variables is statistically controlled. Several possible explanations for these findings are discussed.

Alcohol Drinking↗
PubMed1982

Cholesterol levels in young adulthood and subsequent cancer: a preliminary note.

In a study of the serum cholesterol of 30 male medical students who later developed major cancer, no consistent relationship between baseline cholesterol level and cancer was found during follow-up studies extending for up to 33 years. However, different cancer types seemed to have different cholesterol profiles: subjects who developed melanoma or lung cancer had relatively low initial levels, while subjects who developed cancer of the digestive system, brain or urinary bladder tended to have high initial values. Sequential cholesterol measurements made on two men with cancer of the colon are presented. It is suggested that such sequential cholesterol studies combined with knowledge of the types of cancers involved would help to clarify such complex interrelationships as may exist. The implications of a two-population hypothesis are discussed.

Adult↗
PubMed1982

Blood pressure levels in young adulthood as predictors of hypertension and the fate of the cold pressor test.

In a study of the circulatory characteristics of 78 male medical students who later developed hypertension, no relationship was found between response to the cold pressor test and subsequent hypertension. Casual and resting blood pressure and heart rate measurements were all significantly higher in medical school in subjects who later developed hypertension than in two groups of control subjects who have remained in good health. Of the circulatory characteristics measured, a casual systolic pressure value greater than or equal to 125 mmHg in medical school was found to be the most predictive of future hypertension. A significant positive association was also found between parental hypertension and the presence of hypertension in the subject. When the two risk factors--higher casual systolic pressure in youth and parental hypertension--occur together, their predictive power is shown by the odds ratio of 12.65 (x2 = 12.87, 1 d.f., p less than .001).

Adult↗
PubMed1982

Cancer in families of former medical students followed to midlife: prevalence in relatives of subjects with and without major cancer.

In an ongoing longitudinal study of former medical students, now physicians in midlife, the prevalence of cancer among relatives of 46 probands affected by cancer has been compared with that of two control groups of cancer-free probands. Overall, the prevalence of cancer among relatives of the three groups of probands was similar. However, male probands with cancer appeared to have a greater prevalence of cancer among their relatives than did male cancer-free probands, while the corresponding comparisons for the smaller groups of female probands showed the opposite tendency. Among the relatives of cancer probands of either sex, there was evidence of familial clustering of cancer. Where two relatives in a proband's family had the same type of cancer, the two relatives were usually on the same side (paternal or maternal) of the family. Ages at onset of cancer and types of cancer in relatives of the cancer and cancer-free probands did not reveal any significant differences.

Adult↗