Biomedical subjects
Y Tesfaye
Publications and source records attributed to Y Tesfaye.
Trends in clinic fees at U.S. dental schools--academic year 1986-87 to 1992-93.
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Effect of scopolamine on spontaneous yawning in men.
The effect of scopolamine hydrobromide (0.4 mg s.c.) on spontaneous yawning was studied in 16 male volunteers in a double-blind study. Scopolamine (or placebo) was given 60 min before (-60 min) placebo (physiological saline s.c.) (time 0 min) and yawning monitored from -15 to +60 min by recording displacement of the lower jaw and storing the traces on diskettes. After placebo, the number of yawns was 5.3 +/- 1.4 (means +/- SE) and after scopolamine pretreatment 4.3 +/- 1.6 (p = NS). Drowsiness was assessed with the Stanford Sleepiness Scale and the Analog Sleepiness Scale at -15, 0, +20, +40, +60 min. There was no significant correlation between total sleepiness scores (area under the curve, 0 min to +60 min), peak sleepiness score or peak increment in sleepiness score and number of yawns on either scale. These data suggest that (a) spontaneous yawning in man is not mediated by a central muscarinic cholinergic link, and (b) the assumed relationship between drowsiness and yawning remains to be verified experimentally.
Tetrahydroaminoacridine-lecithin combination treatment in patients with intermediate-stage Alzheimer's disease. Results of a Canadian double-blind, crossover, multicenter study.
We studied the efficacy and safety of oral tetrahydroaminoacridine (THA) combined with lecithin in 52 patients with Alzheimer's disease. The maximal tolerated dose of THA (up to 100 mg per day) was determined during an eight-week titration period, after which the tolerated dose of THA or placebo was given during two sequential randomized periods of treatment lasting eight weeks each. Highly purified lecithin (4.7 g per day) was administered during all phases of the study. Efficacy was expressed in terms of scores on the Mini-Mental State (MMS) test, the modified MMS test, the Hierarchic Dementia Scale, the Rapid Disability Rating Scale-II, and the behavioral scale of Reisberg et al. Safety was assessed by careful clinical monitoring as well as serial measurements of liver aminotransferases. Forty-six patients completed the titration period, and 39 completed the double-blind period, during which only the MMS score showed a small but significant increase (P less than 0.05) after four weeks of treatment with THA. Autonomic side effects of THA were common but mild. Reversible elevations of serum aspartate and alanine aminotransferase levels to three or more times the upper limit of normal occurred in 17 percent of patients; most of the patients affected were women. A liver biopsy performed in one patient showed resolving focal liver-cell necrosis. These studies fail to demonstrate a significant clinical benefit of THA given orally in a maximal dose of 100 mg per day over a period of eight weeks in combination with lecithin.
Apomorphine: clinical studies on erectile impotence and yawning.
1. The erectile response to the short-acting dopamine (DA) receptor agonist, apomorphine (Apo) HCl (0.25, 0.5, 0.75 and 1.0 mg sc), and placebo was evaluated in 28 impotent patients and penile circumference monitored using a mercury strain gauge and strip chart recording. 2. A full erection (increment in penile circumference greater than 2 cm and lasting at least one minute) occurred in 17 patients with Apo; no erection developed after placebo. An erection occurred in 6/8 patients with impaired glucose tolerance, 2/6 patients with diabetes mellitus and in both patients on lithium. 3. Nine patients who responded to Apo were treated in an open trial with bromocriptine; 6 reported improvement in potency. 4. Impairment in DA function may play a role in idiopathic impotence and in impotence associated with impaired glucose tolerance and diabetes mellitus. 5. An erectile response to Apo may predict therapeutic response to bromocriptine or other long acting dopaminergic agents. 6. Lithium, which inhibits DA-sensitive adenylate cyclase, does not prevent Apo-induced erections. This provides further support indicating that Apo induces erections by an effect on D2 receptors. 7. The yawning response to placebo and four doses of Apo HC1 (3.5, 5.0, 7.0, and 10.5 ug/kg sc) was evaluated in five normal men using a polygraphic technique. The yawning response was also assessed in normal young (less than 30 yrs; N = 16) and elderly (greater than 60 yrs; N = 12) volunteers. 8. Under experimental conditions of study, placebo induced spontaneous yawning. This was antagonized by 3.5 and 5.0 ug/kg Apo HC1 but increased by 7.0 ug/kg Apo HC1. These observations are compatible with the view that Apo HC1 in doses of 3.5-5.0 ug/kg stimulates presynaptic DA receptors whereas 7.0 ug/kg stimulates postsynaptic DA receptors. 9. Spontaneous and Apo-induced yawning were significantly decreased in the elderly which suggests that D2 receptor function declines with normal aging.
Some biochemical actions of carnitylcholine, a neuromuscular blocking agent.
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Growth hormone response to apomorphine, a dopamine receptor agonist, in normal aging and in dementia of the Alzheimer type.
The growth hormone (GH) response to the dopamine (DA) receptor agonist, apomorphine HCl (Apo) (0.5 mg SC) was studied in young and elderly normal subjects as well as in patients with dementia of the Alzheimer type (DAT) and controls matched for age, gender and Quetelet index. The GH response was significantly decreased in normal elderly men (mean age 67.3 years; N = 16) compared with young men (mean age 21.2 years; N = 12) and in elderly women (mean age 65.4 years; N = 9) compared with young women (mean age 25.5 years; N = 6) in the luteal phase but not in the early follicular phase. Young men had a significantly greater GH response than young women in either phase of the menstrual cycle. The decline in GH response with normal aging may be related to a decrease in sex steroid activity. There was no significant difference in GH response between DAT patients (N = 15) and paired controls. This suggests that hypothalamic D2 receptor function regulating GH secretion is not altered in DAT.