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Biomedical subjects

E Pratt

Publications and source records attributed to E Pratt.

8 recordsLinked to original sources

Alcohol consumption alters insulin secretion and cardiac autonomic activity.

BACKGROUND: Alcohol may have a cardioprotective effect. One possible mechanism is by modifying insulin resistance/secretion. The aims of this study were: (i) to examine the effect of short-term alcohol consumption on the metabolic control of glucose tolerance; (ii) to study the influence of short-term alcohol consumption on cardiac autonomic activity using spectral analysis of heart rate variability. METHODS: Twenty-one healthy subjects, in a randomized crossover design, either received three units of ethanol daily for 1 week or abstained from ethanol. The control of glucose tolerance was assessed using the intravenous glucose tolerance test with minimal modelling. RESULTS: There was no difference in fasting glucose, fasting insulin or insulin sensitivity between the two groups. Alcohol showed a lower insulin first phase insulin response (no alcohol 659.0 +/- 394.1 SD, alcohol 535.2 +/- 309.1) pmol L-1 min-1, P = 0.027). There was no difference in heart rate or blood pressure but a significant difference in the ratio of high to low frequency spectral power of heart rate variability; (no alcohol 4.55 +/- 3.78, alcohol 8.16 +/- 6.77, P = 0.033). This suggests decreased sympathetic and/or increased vagal modulation of heart rate in the alcohol group. CONCLUSION: The finding of no difference in insulin sensitivity between the two groups contrasts with, but does not entirely contradict, the results of previous epidemiological studies--perhaps suggesting that longer term changes such as liver enzyme induction may be important. The difference in insulin secretion questions the validity of previous studies of the influence of alcohol on insulin sensitivity, where insulin levels were used as a surrogate for insulin resistance.

Adult↗

Antibiotic susceptibility profiles for group B streptococci isolated from neonates, 1995-1998.

Antibiotic susceptibility profiles were analyzed for 119 invasive and 227 colonizing strains of group B streptococci isolated from neonates at 6 US academic centers. All strains were susceptible to penicillin, vancomycin, chloramphenicol, and cefotaxime. The rate of resistance to erythromycin was 20.2% and to clindamycin was 6.9%. Resistance to erythromycin increased in 1997. Type V strains were more resistant to erythromycin than were type Ia (P=.003) and type Ib (P=.004) strains and were more resistant to clindamycin than were type Ia (P<.001), type Ib (P=.01), and type III (P=.001) strains. Resistance rates varied with geographic region: in California, there were high rates of resistance to erythromycin and clindamycin (32% and 12%, respectively), and low rates in Florida (8.5% and 2.1%, respectively). Penicillin continues to be the drug of choice for treatment of group B streptococcus infection. For women who are penicillin intolerant, however, the selection of an alternative antibiotic should be guided by contemporary resistance patterns observed in that region.

Anti-Bacterial Agents↗

Does co-aggregation of the CD45 and CD3 antigens inhibit T cell antigen receptor complex-mediated activation of phospholipase C and protein kinase C?

The binding of agonistic monoclonal antibodies (mAb) to the CD3 antigen in T cells induces a rapid increase in tyrosine phosphorylation, inositive phosphate (IP) production, a rise in intracellular calcium and protein kinase C (PKC) activation. These intracellular signals have been implicated in the control of interleukin-2 and interleukin-2R receptor gene expression, thereby regulating T cell proliferation. Previous studies have shown that co-ligation of the CD45 and CD3 antigens inhibits CD3-induced tyrosine phosphorylation, IP production, calcium signals and T cell proliferation. It has therefore been suggested that the CD45 antigen uncouples the T cell receptor (TcR) from mitogenic signal pathways. In this study co-ligation of the CD3 and CD45 antigens with precisely constructed bispecific mAb did not inhibit CD3-induced T cell proliferation, IP production, calcium signals, diacylglycerol production or PKC activation. Furthermore, co-ligation of CD3 and CD45 antigens already cross-linked with IgM mAb did not lead to inhibition of CD3-induced calcium signals. Inhibitions of CD3-induced intracellular signals were observed following co-ligation of IgG CD45 and CD3 mAb with anti-IgG (F(ab')2 fragments. However, comparable inhibitions were also noted following co-ligation of CD3 with other abundant cell-surface antigens such as CD5 and LFA-1, and inhibitions were only observed when the CD3 mAb used required cross-linking to induce signals. These results suggested that the inhibitory effects of CD45 IgG mAb were not specific and were caused by the prevention of CD3-CD3 cross-linking following CD3 antigen co-ligation with other cell surface molecules. These findings are inconsistent with a specific inhibitory role for the CD45 phosphotyrosine phosphatase in uncoupling the TcR from mitogenic signal pathways.

Antibodies, Monoclonal↗

Psychological and behavioral benefits of a stress/type A behavior reduction program for healthy middle-aged army officers.

Twenty army officers who participated in a stress/type A behavior reduction program and a comparison group of 17 officer nonparticipants volunteered to undergo a battery of psychological and behavioral tests before and after the program. Following the program, participants displayed a significantly greater reduction in average daily caloric intake and levels of perceived stress, anxiety, hostility, depression, psychological distress, and type A behavior as compared to the officers who did not participate in it. Given the fact that most of these psychological and behavioral factors have been found in previous studies to be related to an increased risk for coronary artery disease, it seems that the changes reported by the participants in the program are potentially healthful.

Adaptation, Psychological↗

Problems associated with rabies preexposure prophylaxis.

With the rabies vaccine presently available for preexposure prophylaxis, 20% of all individuals do not have seroconversion following routine immunizations, and 5% are allergic to this vaccine. Two experimental rabies vaccines of cell culture origin offering greater purity and potency were evaluated by means of a double-blind experiment. Thirty-one volunteers who did not have seroconversion or who were allergic to duck embryo rabies vaccine received rabies vaccine produced in either human diploid cell culture (WI-38), or hamster kidney-cell culture. All volunteers had seroconversion within 14 days of receiving a single injection of other experimental vaccine. Clinical side effects were only minor.

Adult↗