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Biomedical subjects

M B Hamner

Publications and source records attributed to M B Hamner.

22 records · Page 2Linked to original sources

Plasma beta-endorphin levels in post-traumatic stress disorder: a preliminary report on response to exercise-induced stress.

Post-traumatic stress disorder (PTSD) may be associated with changes in endogenous opioid peptide function. To test this hypothesis, 10 male Vietnam combat veterans with PTSD and 8 age-matched male controls underwent a standard grade-incremented exercise treadmill stress test. Plasma beta-endorphin measurements were obtained at rest and following maximal exercise. Resting plasma beta-endorphin levels were comparable between groups. Post-exercise plasma beta-endorphin levels were significantly higher than resting levels in the PTSD patients only (P less than 0.05). These pilot data suggest a differential alteration in plasma beta-endorphin response to exercise in PTSD.

Adult↗

Effects of lipid A and liposomes containing lipid A on platelet and fibrinogen production in rabbits.

The effect of the lipid A moiety of endotoxin on platelet and fibrinogen production was studied in rabbits. Lipid A was infused intravenously in doses ranging from 1 to 100 micrograms/kg body mass; 18 hr later, selenomethionine-75Se was injected intravenously and its incorporation into fibrinogen and platelets determined. Lipid A in saline stimulated fibrinogen and platelet production, but the dose required was 50--100 times that required for an intact endotoxin. Although lipid A solubilized in triethylamine (TEA) was at least 60 times more active in the Limulus amebocyte lysate assay than was lipid A suspended in saline, the sensitivity of platelet and fibrinogen production to solubilized lipid A was increased only twofold. Incorporation of lipid A into liposomes had no effect on its Limulus activity. Lipid A in liposomes continued to stimulate platelet, but not fibrinogen, production. Leukopenia that was induced by lipid A in TEA did not occur when rabbits received the same dose of lipid A in liposomes. Lipid A, like intact endotoxin, can stimulate platelet and fibrinogen production and induce leukopenia but the doses required are high. The low solubility of lipid A in aqueous solutions may be only one factor that determines its biologic activity.

Animals↗

Clonazepam-related sexual dysfunction in male veterans with PTSD.

Medication-induced sexual dysfunction can significantly interfere with patients' quality of life and lead to poor compliance. This retrospective study examined the records of 100 male veterans with post-traumatic stress disorder (PTSD) selected in alphabetical order from an active treatment file of 230 patients. Forty-two patients had received clonazepam (mean maximum dose: 3.4 +/- 1.6 mg/day) at some point during their treatment. Of these, 18 (42.9%) complained of significant sexual dysfunction (primarily erectile dysfunction). Eighty-four patients received diazepam (mean maximum dose: 52.1 +/- 29.7 mg/day), nine received alprazolam (mean maximum dose: 5.2 +/- 2.8 mg/day) and eight received lorazepam (mean maximum dose: 3.8 +/- 2.4 mg/day). None of these patients complained of sexual dysfunction during treatment with these three other benzodiazepines. Our findings suggest that benzodiazepines, particularly clonazepam in the current study, can be a cause of sexual dysfunction in many male patients. Prospective studies comparing the overall clinical utility of various benzodiazepines are indicated in this and other clinic populations.

Adult↗