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Biomedical subjects

J Volavka

Publications and source records attributed to J Volavka.

At least 127 records · Page 7Linked to original sources
PubMed1979

EEG response to sine wave modulated light in XYY, XXY, and XY men.

Ten XYY, 14 XXY, and 47 control XY men were located in a birth cohort of non-institutionalized, tall men. Their EEGs were recorded during stimulation with sine were modulated light; 2.5, 5, 10 and 20 Hz were the modulation frequencies. EEGs with and without stimulation were subjected to power spectral analysis. The frequency-specific EEG change due to visual stimulation (i.e. photic driving) was studied. The XYY subjects showed generally lower levels of driving than their XY controls. At stimulation frequencies of 10 and 20 Hz, the EEG driving in the XYY subjects were significantly smaller when measured in the same frequency bands (i.e. 10 and 20 Hz). In addition, stimulation at 10 Hz elicited a significantly smaller response at the third harmonic frequency (i.e. 30 Hz) in the XYY subjects. No consistent differences in EEG driving were detected between the XXY subjects and their XY controls, or between XXY and XYY subjects.

Adult↗
PubMed1979

Classification and bioavailability studies with WE 941 by quantitative pharmaco-EEG and clinical analyses.

Psychoactivity, pharmacodynamic properties and drug tolerance of 2-bromo-4-(2-chlorophenyl)-9-methyl-6H-thieno[3,2-f]1,2-(4-triazolo)[4,3-a][1,4]diazepine (WE 941), a new triazolodiazepine, were studied in 10 normal subjects utilizing quantitative pharmaco-EEG and clinical evaluation methods. In the double-blind, placebo-controlled trial, the subjects received randomized at weekly intervals oral single doses of 0.1 mg, 0.3 mg and 0.5 mg WE 941, placebo, and 30 mg flurazepam as reference substance. Measurements were obtained before and at the 2nd, 4th, 6th h post drug. EEG power spectral density analysis demonstrated no changes after placebo, while WE 941 and flurazepam induced statistically significant alterations characterized by an increase in beta-activity, a decrease in alpha-activity and increase in average frequency ("anxiolytic pharmaco-EEG profile"). In addition, 0.3 mg and 0.5 mg WE 941 and 30 mg flurazepam produced a significant augmentation of delta-activity indicating hypnotic qualities. Considering spontaneous and placebo-induced alterations, evaluation of the time- and dose-effect relationship indicated that all active substances exerted a tranquilizing effect throughout 8 h, while the hypnotic properties of 0.1 mg WE 941 were minimal (up to the 4th h), those of 0.3 mg WE 941 were moderate (up to 6 h) and those of 0.5 mg WE 941 were marked (up to 8 h). The dosage equipotent to 30 mg flurazepam is 0.3 mg WE 941. Heart rate and blood pressure exhibited no relevant changes, while side effects including fatigue, drowsiness and dizziness were mostly observed after the highest dosage of WE 941.

Adult↗
PubMed1978

Endorphins in psychiatry: an overview and a hypothesis.

This article presents an overview of the biochemistry, pharmacology, and physiology of endogenous opioid peptides (endorphins). Clinical psychopharmacology of exogenous opiate agonists and antagonists is reviewed. The evidence presented in the review is compatible with a hypothesis that the level of functional endorphins may be related to psychological events, with a normal level needed for psychological homeostasis. One corollary of this hypothesis is that the level of opioids in the brains of the mentally ill may be disturbed. Therapeutic implications of this hypothesis are considered.

Animals↗
PubMed1978

Methadone dose, plasma level, and cross-tolerance to heroin in man.

The development of cross-tolerance between methadone and heroin was studied in postaddict volunteers who had been drug-free for at least 6 weeks. Two methadone dose schedules were used; each was employed in six subjects. One schedule brought the subjects to a dose of 40 mg, while the other brought them to 80 mg of methadone a day. Subjects received injections of heroin (0.214 mg/kg) and placebo at various times before and during methadone treatment. Pupillary and subjective effects of injections were measured. Plasma levels of methadone were determined concurrently. Subjects on both treatment schedules developed an incomplete cross-tolerance to this dose of heroin. As the dose and plasma level of methadone increased with time, the cross-tolerance to all heroin effects increased. Plasma levels did not affect the development of cross-tolerance independently of methadone dose. The most important contribution to the cross-tolerance to pupillary effects was made by the duration of methadone treatment. Furthermore, the cross-tolerance to the subjective effects of heroin developed earlier than that to the pupil effect.

Adult↗
PubMed1978

Treatment of the alcoholic organic brain syndrome with EMD 21657. A derivative of a pyritinolmetabolite: double-blind clinical, quantitative EEG and psychometric studies.

The efficacy of EMD 21657--a derivative of a pyritinolmetabolite--with regard to the improvement of the organic brain syndrome (OBS) of chronic alcoholics was investigated in a double-blind study utilizing clinical, psychometric and quantitative EEG evaluation. Nineteen patients received 3 x 300 mg EMD and 21 patients 3 x 1 dragee placebo for 6 weeks. The groups did not differ in regard to age, sex, weight, height, alcohol anamnesis or IQ. The hospitalized patients were examined before as well as at the end of the second, fourth and sixth week of drug treatment. While the overall evaluation by the psychiatrist and patients at the end of the period of treatment did not show marked intergroup differences, the clinical global impression scale and the OBS rating scale demonstrated that both groups showed a significant reduction in their OBS and that improvement with EMD 21657 therapy was significantly superior to the one with placebo. Psychometric analysis also exhibited a significant superiority of EMD in regard to the general, associative, numeric and total verbal memory, concentration and attention variability. Psychovisual memory and the quantative aspects of attention showed opposite findings. Flickerlight fusion frequency, reaction time and after-image did not change significantly. The psychomotor activity improved significantly more with EMD than placebo; this was especially pronounced in the left hand. Affect and mood improved also more with EMD than placebo. Side effects were observed more frequently under active treatment and were characterized by temporary headaches. Power spectral density analysis of the EEG revealed in both groups a decrease of delta, fast alpha and beta activities and an increase in theta and slow alpha activity, but changes during EMD treatment more frequently reached the level of statistical significance than with placebo. The most consistant finding was the theta augmentation under EMD treatment. It was concluded that EMD 21657 is a CNS-effective drug with pronounced nootropic and slight thymotropic properties.

Adult↗
PubMed1977

Naloxone in chronic schizophrenia.

The specific narcotic antagonist naloxone (0.4 milligram) was given intravenously to seven chronic schizophrenics who reported that they had very frequent auditory hallucinations. Saline solution was used as a placebo. The coded study did not reveal any effect of naloxone on hallucinations or on global psychopathology.

Adult↗
PubMed1977

EEG spectra in XYY and XXY men.

Ten XYY, 13 XXY, and 45 control XY men were located in a birth cohort of tall men (non-institutionalized), and their EEGs were subjected to computer analyses. The XYY men showed a significantly slower alpha activity and more power in the 3.3--9.6 c/sec band than their XY controls. There were no consistent EEG differences between the XXY men and their controls.

Adult↗
PubMed1977

Electroencephalograms of XYY and XXY men.

Abnormal EEGs have been reported in XYY and XXY men located in psychiatric hospitals and prisons. In general, persons resident in institutions are more likely to exhibit EEG abnormalities than "normal" population, and this bias of ascertainment has complicated the interpretation of these results. The present study was conducted in Denmark. Chromosome determinations were made on 4,140 men selected from a birth cohort of 31,438 men. Twelve XYY and 16 XXY men were detected. Appropriate XY control groups were selected from the same population. The XYY men were found to have a significantly lower average frequency of the occipital alpha activity than their controls. The XYY and XXy men showed significantly more theta activity than the controls.

Adult↗
PubMed1976

Naltrexone: disposition, metabolism, and effects after acute and chronic dosing.

The disposition of naltrexone during acute and chronic administration of 100-mg oral dose was studied in 4 subjects. Following an acute dose the mean (X) peak naltrexone plasma level was 43.6 +/- 29.9 ng/ml at 1 hr and for the major biotransformation product, beta-naltrexol, was 87.2 +/- 25.0 ng/ml at 2 hr. Twenty-four hours after the dose the X levels of naltrexone and beta-naltrexol declined to 2.1 +/- 0.47 and 17.6 +/- 5.0 ng/ml, respectively. Following chronic administration and X peak plasma levels of naltrexone and beta-naltrexol rose to 46.4 +/- 18.5 and 158.4 +/- 89.9 ng/ml at 1 hr, but by 24 hr both compounds declined to levels of the same order as in the acute state at 24 hr. Plasma levels of naltrexone and beta-naltrexol measured 24 hr after the daily doses of naltrexone throughout the study indicated that steady-state equilibrium was rapidly attained and that there was no accumulation of naltrexone and beta naltrexol in the plasma after chronic treatment on 100 mg oral doses. Biexponential kinetics were observed for naltrexone and beta-naltrexol in the first 24 hr. The half-life of naltrexone and beta-naltrexol decreased slightly from the acute to thechronic study from 10.3 +/- 3.3 to 9.7 +/- 1.1 hr and from 12.7 +/- 2.6 to 11.4 +/- 2.0 hr. The plasma levels of naltrexone declined slowly from 24 through 72 hr from 2.4 to 1.7 ng/ml, with an apparent half-life of 96 hr. The renal clearance data indicate that naltrexone is partially reabsorbed while beta naltrexol is actively secreted by the kidney. During acute and chronic naltrexone administration the mean fecal excretion was 2.1% and 3.6% while urinary excretion was 38% and 70% of the dose in a 24-hr period. Opiate antagonism to 25 mg heroin challenges was nearly complete through 48 hr after naltrexone. At 72 hr the objective responses reappeared to a greater extent than the subjective ones. Correlation coefficient (r) between naltrexone plasma levels and opiate antagonism was 0.91 and between individual half-life of naltrexone and opiate antagonism it was 0.99.

Adult↗
PubMed1976

ACTH 4-10: a study of toxicological and behavioral effects in an aging sample.

Placebo and ACTH 4-10 (in ascending dosages from 15 to 60 mg) were administered subcutaneously to normal aging subjects (mean, 65.6 years). Measurements were obtained for EEG, EKG, SMA-12, urine, and blood pressure. Behavioral tasks measuring reaction time (RT), short-term memory, perceptual speed, and motor speed were administered. There were no pre- to post-injection changes in SMA-12, urine, EEG, and EKG. There was an improvement in RT time that was dose related. These data indicate that ACTH 4-10 is (1) safe to administer to an aging population and (2) combined with data on young adults suggest that it may act on the attentional/arousal processes. Results suggest that ACTH 4-10 may have stimulant-like properties on behavior without effecting the CNS and cardiovascular system.

Adrenocorticotropic Hormone↗
PubMed1976

Short-term effects of naltrexone in 155 heroin ex-addicts.

The narcotic antagonist naltrexone was administered for periods of up to 8 months to a total of 155 patients at a dose of 40-200 mg per day. The antagonistic effect of naltrexone was tested by injections of heroin. Eighty milligrams of natrexone was effective for 48hr. The antagonistic effect decreased at 72 hr after the administration of 120-200 mg of naltrexone. Laboratory tests indicated no signs of toxicity. Naltrexone may elicit an increase in blood pressure and opigastric pain. Neither of these side effects appear clinically important. No signs of dependence on naltrexone were detected. These results suggest that naltrexone may be useful for clinical treatment of opiate dependence.

Abdomen↗
PubMed1975

Methadone in man: pharmacokinetic and excretion studies in acute and chronic treatment.

The biologic disposition of methadone in acute and during chronic administration was studied in 12 human volunteers. In the acute study a biexponential methadone plasma level decay was observed. The acute primary half-life (t1/2) of 14.3 hr in combination with the acute secondary t1/2 of 54.8 hr were longer than the single exponential chronic t1/2 of 22.2 hr determined in the same subjects. The urinary and fecal excretion of methadone and its mono-N-demethylated metabolite increased from 22.2% in the acute to 62.0% in the chronic phase of the study. The urinary metabolite 1 to methadone ratio tripled from the acute to the chronic phase. The pupillary effects of methadone monitored throughout 24 hr were nearly the same in magnitude in the acute and the chronic studies, whereas the plasma levels increased 3- to 8-fold following chronic methadone administration. These findings suggest that both dispositional and pharmacologic tolerance are involved in the development of tolerance following chronic administration of methadone.

Adult↗