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Biomedical subjects

C MacLean

Publications and source records attributed to C MacLean.

10 recordsLinked to original sources
PubMed1991

Evaluation of first- and second-generation RIBA kits for detection of antibody to hepatitis C virus.

Samples reactive by first-generation recombinant immunoblot assay (RIBA) to detect antibody to hepatitis C virus (anti-HCV) (RIBA-1 [Chiron, Calif.]) remained reactive by a second-generation test (RIBA-2) for HCV antibodies. A total of 75% of specimens indeterminate by RIBA-1 became reactive, 12.5% were nonreactive, and 12.5% remained indeterminate by RIBA-2. Among RIBA-1-nonreactive specimens, 12.0% became positive and 5.1% became indeterminate by RIBA-2. The antigens c33c and c22-3 have increased the sensitivity of RIBA-2.

Diagnostic Errors↗
PubMed1991

The genetic epidemiology of bulimia nervosa.

OBJECTIVE: The authors seek to clarify, from both an epidemiologic and genetic perspective, the major risk factors for bulimia nervosa and to understand the relationship between narrowly defined bulimia and bulimia-like syndromes. METHOD: Personal structured psychiatric interviews were conducted with 2,163 female twins from a population-based register. Psychiatric disorders were assessed using DSM-III-R criteria. RESULTS: Lifetime prevalence and risk for narrowly defined bulimia were 2.8% and 4.2%, respectively. Including bulimia-like syndromes increased these estimates to 5.7% and 8.0%, respectively. Risk factors for bulimia included 1) birth after 1960, 2) low paternal care, 3) a history of wide weight fluctuation, dieting, or frequent exercise, 4) a slim ideal body image, 5) low self-esteem, 6) an external locus of control, and 7) high levels of neuroticism. Significant comorbidity was found between bulimia and anorexia nervosa, alcoholism, panic disorder, generalized anxiety disorder, phobia, and major depression. Proband-wise concordance for narrowly defined bulimia was 22.9% in monozygotic and 8.7% in dizygotic twins. The best-fitting model indicated that familial aggregation was due solely to genetic factors with a heritability of liability of 55%. A multiple threshold model indicated that narrowly defined bulimia nervosa and bulimia-like syndromes represented different levels of severity on the same continuum of liability. CONCLUSIONS: The liability to fully syndromal bulimia nervosa, which affects around one in 25 women at some point in their lives, is substantially influenced by both epidemiologic and genetic risk factors. The same factors that influence the risk for narrowly defined bulimia also influence the risk for less severe bulimia-like syndromes.

Adolescent↗
PubMed1990

Smoking, pulmonary function, and mortality.

The association of pulmonary function (as percent of predicted forced expiratory volume in 1 second [FEV1]) with total and cause-specific mortality over 15 to 18 years was investigated in a large cohort (5924) of prospectively followed Japanese-American men. Among those who never smoked, pulmonary function was found not to be significantly predictive of total mortality in a multivariate model in which adjustment for variables that might confound the results was made. Among past and current smokers, highly significant associations were found (P < 0.0001). The positive relationship of pulmonary function to mortality in smokers was so strong that it overshadowed these differences in nonsmokers in a model including all smoking groups combined, even after adjusting for smoking. A smoking-pulmonary function interaction term added to this model was statistically significant (P < 0.003). This illustrates the need for attention to the potential for complex interactions between biologic variables when carrying out multivariate statistical analysis. Findings for cardiovascular and noncardiovascular mortality were similar. This analysis indicates that while pulmonary function is associated with subsequent mortality, the relationship is significantly associated with smoking history.

Asian↗
PubMed1990

Orthostatic hypotension, catecholamines, and alpha-adrenergic receptors in mitral valve prolapse.

The reported association of mitral valve prolapse with autonomic dysfunction and neuroendocrine abnormalities is derived from studies of patients selected because of symptoms or specifically referred for investigation. To determine whether such associations occur in nonreferred and unselected women with mitral valve prolapse, we measured blood pressure, heart rate, and norepinephrine response to standing in 13 volunteers with mitral valve prolapse and in 11 control subjects. Platelet alpha-adrenergic receptor quantity and affinity on standing also were determined in all persons. No significant differences were found between the groups in any of these measurements. Although small subsets of women with mitral valve prolapse may indeed have associated neuroendocrine epiphenomena and autonomic dysfunction, it is probably incorrect to generalize these findings to the vast spectrum of those with mitral valve prolapse.

Adolescent↗
PubMed1989

Response bias in the Honolulu Heart Program.

The 14-year incidence rates (1969-1982) for coronary heart disease, cerebrovascular disease (stroke), total mortality, and cause-specific mortality were compared between 8,006 examined and 3,130 nonexamined men of the Honolulu Heart Program using identical surveillance procedures. There was a significant decrease in examination participation with increasing age. Examined men smoked less, weighed more, had a higher level of education, and had a lower percentage of never-married status than did nonexamined men. Total mortality rates, cancer mortality rates, and coronary heart disease incidence rates were higher in nonexamined men, while there were no differences in stroke rates. The average annual response error for total mortality and coronary heart disease rates was underestimated at 8.7% and 5.4%, respectively. The differences in rates were greatest during the first half of the follow-up period and converged during the second half. By the end of 10 years, there were no differences between nonexamined and examined men for any of the endpoints studied. The pattern of convergence of rates suggests a diminishing healthy participant advantage over time. In conclusion, a response bias did occur in this study, but the effect was small and did not alter any of the earlier findings concerning the relative incidence of cardiovascular disease. Because the degree of response bias can vary widely depending on when during follow-up a particular analysis is undertaken, it is recommended that prospective studies monitor, insofar as possible, a sample of nonparticipants in order to ensure valid results.

Aged↗
PubMed1986

The product of gene US11 of herpes simplex virus type 1 is expressed as a true late gene.

The genes of herpes simplex virus type 1 (HSV-1) can be divided into at least three temporally regulated groups termed immediate early (IE), early and late. We have studied in detail the expression of a member of the late class of genes, US11, which encodes a polypeptide of apparent molecular weight 21K. Highly specific and sensitive probes were used to monitor US11 RNA and protein synthesis during HSV-1 infection of tissue culture cells in the presence and absence of phosphonoacetic acid, an inhibitor of viral DNA replication. The results were compared with a similar study of the products of a delayed early gene, US6, encoding glycoprotein D (gD). It was found that the patterns of RNA and protein synthesis from US11 were significantly different to those of gD. US11 products appeared later and accumulated until late in infection, while gD RNA was significantly reduced at late times. In the presence of the inhibitor of DNA synthesis, US11 gene expression was reduced 50- to 100-fold while gD expression was reduced five- to tenfold. We conclude that US11 behaves as a true late gene during HSV-1 infection. However, the use of sensitive assays, which allowed the detection of very low levels of US11 gene products under conditions designed to eliminate DNA replication, brings into question the absolute requirement for DNA replication for the expression of a true late HSV-1 gene. These results are discussed in terms of current models for the regulation of late gene expression.

Animals↗