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Biomedical subjects

M H Ebert

Publications and source records attributed to M H Ebert.

31 records · Page 2Linked to original sources

Urinary catecholamines and amphetamine excretion in hyperactive and normal boys.

Urinary catecholamines and metabolites and urinary amphetamine excretion were examined for hyperactive and normal boys following a single dose of dextroamphetamine (0.5 mg/kg) and placebo. Hyperactive children showed a significantly faster rate of excretion of amphetamine which could not be accounted for by previous exposure to drug or by signs of neurological involvement. Urinary norepinephrine (NE) was significantly higher for hyperactive than for normal children, but NE excretion did not correlate with motor activity or any measures of arousal. The single dose of amphetamine produced a significant rise in urinary epinephrine excretion (EP) for the normal children but not for the hyperactive group, supporting the notion of a more sluggish catecholamine response to stimulants for hyperkinetic children.

Amphetamine

Effects of self-induced starvation on cardiac size and function in anorexia nervosa.

Cardiac size, function and rhythm were examined in 11 patients with anorexia nervosa. Mean left ventricular, left atrial and aortic dimensions on echocardiogram were below normal adult values at baseline. In addition to decreased cardiac dimensions--ventricular ectopy, relative hypotension, bradycardia and blunted heart rate--response to exercise were noted. Left ventricular systolic function, however, was unimpaired as indicated by normal echocardiographic fractional shortening, and by normal exercise augmentation of ejection fraction determined by radionuclide cineangiography. Eight of the patients responded to treatment with a mean weight gain of 32%. In these eight, cardiac dimensions increased toward normal: left ventricular dimension increased by 13%; left atrial dimension by 20%; aortic dimension by 15% and estimated left ventricular mass by 20%. We conclude that abnormalities of heart size and rhythm occur in patients with anorexia nervosa. However, cardiac dimensions, including left ventricular mass, may increase following nutritional rehabilitation, accompanied by an increase in heart rate and blood pressure.

Adolescent

Couples group therapy as an adjunct to lithium maintenance of the manic patient.

Use of couples therapy groups in conjunction with lithium in the long-term management of married manic-depressive patients is described. Among bipolar patients on lithium, those in couples group therapy had more benign posthospital course than those given minimal support beyond medication. The structure and benefits of the couples group are discussed.

Adult

Studies on the transfer of steroid hormones across the blood-cerebrospinal fluid barrier in the rhesus monkey. II.

The movement of progesterone (P), cortisol (F) and 17-hydroxyprogesterone (17-OHP) across the blood-cerebrospinal fluid (CSF) barrier was determined using six adult male rhesus monkeys with indwelling canulae in the lateral ventricles of their brains. Tritiated steroids were given iv as a bolus followed by a constant 6 h infusion with continuous collection of CSF and periodic sampling of blood before and during the infusion. The amounts of authentic steroid in the plasma and CSF were determined by recrystallization to constant isotopic ratio and the amount of free plasma steroid was determined by equilibrium dialysis against Ringer's solution. Tritiated progesterone was undetectable in the pooled samples of CSF. The average concentration of tritiated 17-OHP in the CSF was 10.3% of the concurrent plasma level while the concentration of tritiated F was 22.5% of the concurrent plasma level. Plasma free steroid was found to be 2.2% for P, 6.3% for 17-OHP and 22.3% for F, showing a rough correlation between steroid entry into the CSF and free steroid concentration in plasma.

Animals

An outline for the analysis of dementia. The memory disorder of Huntingtons disease.

Methods have been developed for assessing the cognitive parameters contributing to a memory disorder. Our findings suggest that individuals with Huntington disease have impairments in the encoding of new information and the consistent retrieval from storage of learned material. Their difficulties lie particularly in the realm of episodic memory.

Adult

Studies on the transfer of steroid hormones across the blood-cerebrospinal fluid barrier in the Rhesus Monkey.

Indwelling canulae were placed in the lateral ventricles of the brains of six adult male rhesus monkeys, and the movement of estradiol-17beta (E2), testosterone (T), and 5alpha-dihydrotestosterone (DHT) across the blood-cerebrospinal fluid (CSF) barrier was measured. Serial samples of blood and CSF were collected every 30 minutes during a 6 hour infusion of the tritiated steroids, and the quantity of free steroid in the blood and CSF was determined by recrystallization to constant specific activity. During the course of the 6-hour infusion, the average CSF concentration of steroid, expressed as dpm/ml, was about 3.5% of the concurrent plasma level of E2, 1.6% of the concurrent plasma level of T, and 0.08% of the concurrent plasma level of DHT. It is proposed that these differences in steroid transfer can be attributed to differential binding of these steroids to testosterone-estrogen-binding globulin (TeBG) in plasma.

Animals

Intravenous probenecid loading. Effects on plasma and cerebrospinal fluid probenecid levels and on monoamine metabolites in cerebrospinal fluid.

Probenecid blocks the active transport from cerebrospinal fluid to blood of homovanillic acid and 5-hydroxyindoleacetic acid, thus increasing cerebrospinal fluid levels of these products of central monoamine metabolism. The half-life in plasma of probenecid given as a single intravenous infusion (40 mg per kilogram of body weight) to patients with either Huntington's chorea or Parkinson's disease averaged about 6.6 hours. In cerebrospinal fluid, peak values for homovanillic acid and 5-hydroxyindoleactic acid occurred in samples collected 8 hours after the 1-hour probenecid infusion was started. Even after 4 hours, however, levels of both monoamine metabolites were significantly increased. There was a positive correlation between cerebrospinal fluid levels of probenecid and the increase in 5-hydroxyindoleacetic acid but not homovanillic acid. Compared with the oral administration of probenecid, the intravenous infusion technique produced more consistent elevations in plasma and cerebrospinal fluid probenecid levels, greater increases in cerebrospinal fluid homovanillic acid values, and fewer gastrointestinal side effects.

Administration, Oral