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Biomedical subjects

M M Ghoneim

Publications and source records attributed to M M Ghoneim.

At least 91 records · Page 5Linked to original sources
PubMed1984

Behavioral effects of diazepam and propranolol in patients with panic disorder and agoraphobia.

The effects of oral doses of diazepam (single dose of 10 mg and a median dose of 30 mg/day for 2 weeks) and propranolol (single dose of 80 mg and a median dose of 240 mg/day for 2 weeks) on psychological performance of patients with panic disorders and agoraphobia were investigated in a double-blind, randomized and crossover design. Both drugs impaired immediate free recall but the decrease was greater for diazepam than propranolol. Delayed free recall was also impaired but the two drugs did not differ. Patients tapped faster after propranolol than diazepam and they were more sedated after diazepam than propranolol. After 2 weeks of treatment, patients tested 5-8 h after the last dose of medication did not show any decrement of performance. These results are similar to those previously found in healthy subjects. Accumulation of drugs was not reflected in prolonged behavioral impairment.

Adult↗
PubMed1984

Comparison of four opioid analgesics as supplements to nitrous oxide anesthesia.

The hemodynamic changes, plasma norepinephrine levels, pupil size, and rapidity of postoperative mental recovery were measured and compared in 72 patients randomly assigned in a double-blind manner to receive either morphine, meperidine, fentanyl, or sufentanil as supplements to nitrous oxide anesthesia. Meperidine, unlike the other opioids, which did not change heart rate, consistently increased it. Hemodynamic responses to laryngoscopy and intubation were suppressed by fentanyl and sufentanil, but not by morphine or meperidine. The sufentanil group was the only group in which median norepinephrine levels remained consistently below preinduction values. The frequency with which opioids had to be administered (doses/hr) was significantly less with sufentanil than with morphine and meperidine. Meperidine produced less constriction of the pupils than the other opioids and the duration of miosis was shorter. Fentanyl and sufentanil were associated with a more rapid return of mental function than morphine and meperidine. Meperidine caused deleterious effects on objective tests of psychomotor and cognitive skills that were not reflected by subjective evaluation of rate of recovery from anesthesia. The authors conclude that moderate doses of fentanyl and sufentanil are better supplements to nitrous oxide anesthesia than morphine or meperidine and that fentanyl and sufentanil are equally satisfactory. Subjective effects of the opioids correlated well with changes in pupil diameter.

Adjuvants, Anesthesia↗
PubMed1983

How often may a Read rebreathing test be repeated?

The minimum duration of the rest period between repeated Read rebreathing tests required to prevent interference between tests is yet unknown. Four male and four female volunteers performed eight Read rebreathing CO2 response tests in a period of 2.5 h. The test-to-test interval was as short as 10 min. No major differences in slope or intercept were found according to time in either the group as a whole or as male and female groups taken separately. There was a slight but nonsignificant depression in slope for the 3rd to 5th tests. The females responded less to a CO2 challenge than did the males. It is concluded that a test-to-test interval as short as 10 min does not effect the results of the Read rebreathing test.

Adult↗
PubMed1982

Diazepam and learning: assessment of acquisition deficits.

Subjects treated with diazepam (0.3 mg/kg) showed significant reductions in performance on multiple-trial free recall, paired-associate learning, and serial learning tasks compared to placebo control subjects. The free recall task showed the largest drug effect with diazepam subjects failing in six acquisition trials to attain the level of performance achieved by placebo subjects on the first trial. Serial position curves in the serial learning task were changed by the diazepam treatment from their usual skewed form to symmetrical functions. Results indicate that diazepam exerts its greatest memory influence on the acquisition of new information.

Adolescent↗
PubMed1981

Memory and performance effects of single and 3-week administration of diazepam.

The effects of diazepam of several cognitive and performance tasks were investigated in 30 healthy volunteers randomly assigned to three groups: A chronic group received diazepam for 21 days; an acute group received placebo during the same period, except at session 4 when they received diazepam; and a third group received placebo only at the sessions. Diazepam was given orally in a dose of about 0.2 mg/kg. Behavioral sessions were conducted before treatment (practice), after one administration (session 2), after 19 days (session 3), after 20 days (session 4), and 7 days following withdrawal (session 5). A single administration of diazepam produced significant memory impairment in both immediate and delayed free recall. Reduced memory performance was the result of impaired acquisition rather than reduced retention. Comparison of the chronic and acute groups in sessions 3 and 4 and analysis of the performance of the chronic group over sessions indicated the development of some tolerance to the memory impairment with continued administration. No residual memory effects were apparent following withdrawal. No other cognitive or psychomotor functions differed among the three treatment groups.

Diazepam↗
PubMed1981

Diazepam effects and kinetics in Caucasians and Orientals.

Mental and psychomotor effects and diazepam kinetics were studied in Caucasian and Orientals. 12 Caucasian and 13 Oriental young adults received on one of two occasions, separated by 2 weeks, either 0.2-mg/kg diazepam or saline intravenously. Serum diazepam and desmethyldiazepam concentrations were measured by electron-capture gas-liquid chromatography in samples drawn up to 72 hr after injection. Serum protein binding was measured by equilibrium dialysis. Subjects were tested on a battery of psychological tests before and 0.5, 2, and 4 hr after treatment. While the free fraction of diazepam was identical in both races (0.02), volume of distribution at steady state (Vdss) was different when calculated as absolute volume (Vdss = 76.55 +/- 9.63 l in Caucasians and 54.96 +/- 4.55 l in Orientals, p = 0.04) and marginally significant when corrected for body weight (Vdssl/kg = 1.10 +/- 0.11 in Caucasian and 0.88 +/- 0.05 in Orientals, p = 0.07). total body clearance (Cl), but not elimination half-life (t 1/2), was higher in Caucasians than Orientals, p less than 0.01; t 1/2 = 37.70 +2- 5.53 hr in Caucasians and 41.77 +/- 3.80 in Orientals). Desmethyldiazepam levels were higher in Orientals than Caucasians. Mental and psychomotor effects were maximal at the first session (0.5 hr), followed by complete recovery by the 4-hr session. Effects were similar in both groups. If repeated dosing causes a higher rate of cumulated diazepam serum levels in Orientals, as expected, there might be deeper brain depression in that group.

Adult↗
PubMed1981

Time course of mental and psychomotor effects of 30 per cent nitrous oxide during inhalation and recovery.

Two experiments were conducted testing the duration of action of nitrous oxide on human performance. In the first experiment, 11 subjects inhaled 30 per cent nitrous oxide for two periods of 40 min each, 45 min apart. Their mental and psychomotor skills were measured using free recall, tapping board, arithmetic and flicker fusion tests before and 2, 12, 22 and 32 min after establishing and end-tidal concentration of N2O of 30 per cent. Recovery was tested using the same tests 2, 12, 22 and 32 min after discontinuation of N2O. Eleven additional subjects inhaled oxygen only and served as a control group. In the second experiment, 8 subjects received both 30 per cent N2O and oxygen in cross-over fashion, and their flicker fusion threshold was measured. When compared to baseline or oxygen administration, N2O significantly impaired tapping rate, number of words recalled, and performance in arithmetic tests. The effects of N2O were maximal at 2 min and remained similar throughout the entire administration. In flicker fusion tests, the effects of N2O were similar to those of stimulant drugs; N2O improved the subjects' ability to discriminate the fusion of flickering light. Recovery was complete in 22 min. The effects of, and recovery from the second administration of N2O were similar to those of the first experiment. There was no evidence of development of tolerance to mental and psychomotor effects of the drug.

Adult↗
PubMed1981

Evaluation of instrumented force platform as a test to measure residual effects of anesthetics.

Recovery from anesthesia was assessed in a controlled manner in 38 healthy student volunteers, using two psychomotor tests (perceptual speed and tapping board) and an instrumented force platform 1, 3, 5 and 7 h after intravenous injection of 0.3 mg/kg diazepam, 2.0 mg/kg methohexital, 6.0 mg/kg thiopental or saline. Postural stability remained unaltered but the performance on psychomotor tests improved when the tests were repeated after saline injection. Methohexital did not induce any changes in body sway or psychomotor performance at the time periods tested when compared with saline. Postural stability of subjects receiving thiopental or diazepam was imparied (P less than 0.001) for 1 and 7 hours after anesthesia, respectively, when compared with saline. The impairment on performance in the psychomotor tests induced by thiopental or diazepam was of smaller magnitude and for diazepam of shorter duration than balance disturbances measured with the body sway tests. Further clinical studies on the use of the instrumented force platform as a fast and easily interpretable guideline for discharge from hospital after different modes of outpatient anesthesia are warranted.

Adult↗
PubMed1980

Diphenhydramine in Orientals and Caucasians.

The kinetics and psychomotor effects of diphenhydramine were investigated in Orientals and Caucasians. Each of 5 Oriental and 5 Caucasian young adults received on 1 of 3 occasions diphenhydramine 50 mg/70 kg body weight either intravenously or orally, or placebo. Plasma levels of diphenhydramine were measured hourly for 8 hr at each session. Tests of subjective sedation and psychomotor performance were performed at hourly intervals. The results showed that after both intravenous and oral diphenhydramine, at all times Orientals had plasma levels approximately half those of Caucasians. With the assumption of linear kinetics and a 1-compartment open model, analysis of the data showed that the volume of distribution (VD) and plasma clearance (Cl) but not plasma half-life (t 1/2) were higher in Orientals than Caucasians: [VD = 480 +/- 24 (SEM) and 292 +/- 36 1/70 kg; Cl = 79 +/- 7 and 51 +/- 7 1/70 kg/hr; t 1/2 = 4.1 +/- 0.4 and 4.3 +/- 0.4 hr]. Unbound diphenhydramine in fresh plasma was higher in Orientals than Caucasians [24.0 +/- 1.9% (SEM) and 14.8 +/- 1.5%] and probably explains the increased VD in Orientals. Orientals had significantly less sedation and deterioration in psychomotor performance.

Adult↗
PubMed1979

The effects and interactions of scopolamine, physostigmine and methamphetamine on human memory.

Seventy college age subjects learned and recalled a series of word lists prior to being injected with methamphetamine (0.2 mg/kg or 0.3 mg/kg), scopolamine (8 microgram/kg), or a placebo. Following the injection subjects were tested for their free recall and recognition of the words and they completed a short-term digit recall task. Subjects who had previously received scopolamine were next injected with either methamphetamine (0.2 mg/kg or 0.3 mg/kg), physostigmine (32 microgram/kg), or placebo, while other subjects received a placebo injection. The above memory procedure was then repeated with a second series of word lists. In addition, subjective feelings were measured with a questionnaire. Scopolamine and methamphetamine did not affect recall of information learned prior to injection. Scopolamine did, however, impair performance in both the digit recall task and in the second series of memory tests. Physostigmine and methamphetamine alleviated most of the memory deficits and sedation produced by scopolamine. Methamphetamine alone produced subjective arousal and a small improvement in recall of words learned after injection and a large increase in incorrect responding.

Adolescent↗
PubMed1978

Pharmacokinetics of thiopentone: effects of enflurane and nitrous oxide anaesthesia and surgery.

Plasma concentrations of thiopentone following the injection of 3.5 mg kg-1 i.v. were studied in six patients who received enflurane and nitrous oxide anaesthesia and six volunteers. We identified a three-compartment open model system containing both a "shallow" and a "deep" peripheral compartment in all the patients and half of the controls, and a two-compartment open model for the remaining volunteers. The distribution of thiopentone to the tissues was very rapid, the alpha and beta distribution half-lives averaging 2.5 min and 46.4 min respectively for the patient group and 2.8 min and 48.7 min for the control group. The wide distribution of the drug was indicated by the apparent volume of distribution, the means of which varied between 2 and 1.5 times body weight. The mean elimination half-life was 5.1 h for the patients and 5.7 h for the volunteers. The return of the drug to the central compartment from the deep peripheral compartment was the rate-controlling factor in its elimination. Neither enflurane and nitrous oxide anaesthesia nor the stress of surgery affected the distribution or clearance of the drug from plasma.

Adult↗