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Biomedical subjects

M Maj

Publications and source records attributed to M Maj.

At least 91 records · Page 5Linked to original sources
PubMed1996

Measuring the potency of pulp mill effluents for induction of hepatic mixed-function oxygenase activity in fish.

A bioassay protocol was optimized for measuring the potency of effluents or waterborne chemicals for inducing mixed-function oxygenase (MFO) activity of rainbow trout (Oncorhynchus mykiss). Measurements of ethoxyresorufin O-deethylase (EROD) can be made with an established endpoint assay using large volumes of reagents and tissue. However, a new kinetic microplate assay offers significant savings in time, reagents, and sample volumes. Data are distributed lognormally and must be log transformed before statistical analyses. EROD activity increases with exposure time to pulp mill effluent, and a 4-d exposure provides a near-maximal response. Optimum fish size conforms to standard practices in fish toxicology; loading rates should not exceed 1 g of fish per liter of test solution per day. Feed should be withheld from test fish 48 h before testing to reduce the variance of measured activity, and anaesthetizing fish with MS-222 does not affect their response to MFO inducers. Pulp mill effluents do not lose their potency during 2-3 wk of exposure at temperatures ranging from -20 to 13 degrees C, whether stored in plastic or glass. Steel containers were associated with slight losses in potency. Bioassays of MFO induction in fish exposed to liquid effluents are practical and conform to standard practice for testing the lethality of waterbone chemicals. The results are sufficiently precise that differences among means based on live fish per treatment can be discriminated statistically when activity changes by threefold or more.

Analysis of Variance↗
PubMed1996

Depressive syndromes and symptoms in subjects with human immunodeficiency virus (HIV) infection.

The association between the infection produced by the human immunodeficiency virus (HIV) and syndromal or subsyndromal depression has been the topic of several studies in recent years. The results of the WHO Neuropsychiatric AIDS Study, conducted in the five geographical areas predominantly affected by the HIV epidemic, suggest that the symptomatic stages of HIV infection are associated with an increased prevalence of depressive symptoms, and, at least in some contexts in which the spreading of the infection is more recent and the social rejection of HIV-seropositive subjects is harsher, may also be associated with an increased prevalence of a syndromal diagnosis of depression.

Acquired Immunodeficiency Syndrome↗
PubMed1996

[Silent myocardial ischemia before and after revascularization].

In 82 patients with unstable ischemic heart disease (IHD) before and after revascularisation (percutaneous transluminal coronary angioplasty-PTCA-in 11 patients and coronary artery bypass graft-CABG-in 71 patients) silent ischemia incidence was observed. In these patients before and after operation election fraction (EF) and wall motion score index (IK) were compared echocardiographically as well as physical ability according to Bruce protocol in treadmill exercise test. Data (EF and IK and exercise test) before and after operation didn't change significantly. Silent ischemia was directed before operation in 17 patients (21.8%) and in 15 patients (19.4%) one month after those procedures.

Adult↗
PubMed1995

Does bright light suppress nocturnal melatonin secretion more in women than men?

Sex differences in the sensitivity of the human pineal gland to the suppressant effect of bright light on melatonin synthesis were studied in 6 healthy men and women. Blood samples were collected in two randomly ordered sessions: in one, subjects rested supine in bed, in the dark, from 21.00 to 7.00 h; in the other session, they were exposed to bright light (2,000 lux) from 2.00 to 4.00 h. In the dark condition, no significant differences were observed between men and women in either the timing or the absolute values of melatonin plasma levels, whereas after bright light exposure, the suppression of plasma melatonin was a 40% greater in women than in men. These findings suggest that, in humans, there is a sex difference in the nocturnal sensitivity of the pineal to light.

Adult↗
PubMed1995

Effects of single and repeated electroconvulsive shock on isoproterenol-stimulated pineal N-acetyltransferase activity and melatonin production in rats.

The response of the pineal gland to acute isoproterenol administration represents a useful tool to investigate beta 1-adrenoceptor function, because the production of melatonin and the activity of its main synthesizing enzyme, N-acetyltransferase (NAT), are regulated by beta 1-adrenergic receptors. In the present study, rats underwent single electroconvulsive shock (ECS) administration (0.80 mA, 0.5 s, at midday), chronic ECS treatment (0.80 mA, 0.5 s, once daily for 8 days), or sham treatments. On the day after the last ECS or sham ECS, animals were injected with isoproterenol hydrochloride (1 mg.kg-1 SC) or volume-matched saline at 1600 h. After single ECS, isoproterenol injection induced a clear-cut increase in both pineal NAT activity and melatonin levels with no significant differences between ECS-treated rats and the sham-treated ones. In rats chronically treated with ECS, the isoproterenol-induced increases in both pineal NAT activity and melatonin content were significantly lower than in sham-treated animals (p < 0.001 for NAT activity; p < 0.005 for melatonin levels; Turkey's test). These data show that the pinealocyte beta-adrenoceptor function is reduced by chronic, but not acute ECS administration, and that this change is not due to the nonspecific stress effect of animal handling or to the acute effects of the last of a series of ECS.

Acetyltransferases↗
PubMed1995

Plasma melatonin and cortisol circadian patterns in patients with obsessive-compulsive disorder before and after fluoxetine treatment.

The circadian rhythms of melatonin and cortisol were evaluated in seven outpatients with obsessive-compulsive disorder (OCD) before and after 8 weeks of fluoxetine treatment (20 mg/day in the first 2 weeks, and 40 mg/day afterwards), and in seven healthy subjects matched to patients on age, sex and season of testing. The results confirm our previous findings of a decreased 24-h production of melatonin (p < .05; two-way ANOVA with repeated measures) and of an increased circadian secretion of cortisol (p < .01) in OCD patients with respect to matched controls, and show, for the first time, that these hormonal alterations do not significantly change after 2 months of fluoxetine administration, in spite of a good clinical improvement. These data suggest that the normalization of the biochemical changes underlying the altered endocrine parameters in obsessive-compulsive patients is not necessary for effective therapy or clinical remission.

Adult↗
PubMed1995

Levosulpiride: a review of its clinical use in psychiatry.

Levosulpiride is the (-)-enantiomer of sulpiride. It has shown greater central antidopaminergic activity, antiemetic and antidyspeptic effects and lower acute toxicity than both the racemic and dextro forms. Several clinical studies indicate that levosulpiride has therapeutic efficacy in depressive and somatoform disorders, as well as in schizophrenic patients with predominant negative features. All controlled studies report a low frequency of extrapyramidal and autonomic side-effects. The increase of plasma prolactin concentration is the major drawback of the use of the drug, but its frequency may be reduced by low dosage.

Administration, Oral↗
PubMed1995

Nonresponse to reinstituted lithium prophylaxis in previously responsive bipolar patients: prevalence and predictors.

OBJECTIVE: The authors explored the prevalence and predictors of nonresponse to reinstituted lithium prophylaxis in bipolar patients who had relapsed after discontinuation of successful lithium treatment. METHOD: The study was conducted with 54 bipolar patients for whom lithium had been reintroduced after one or more recurrences following discontinuation of successful prophylaxis. They were followed up, through bimonthly personal interviews, for 1 year after recovery from the episode during which lithium treatment had been resumed, or up to the first recurrence with onset after lithium reinstitution. RESULTS: During the follow-up period, 44 patients did not have any affective episodes, whereas 10 had at least one recurrence. The only significant difference between the two patient groups was the longer duration of prediscontinuation lithium treatment for the patients who relapsed. CONCLUSIONS: Nonresponse to reinstituted prophylaxis should be considered among the possible risks of the interruption of effective long-term lithium treatment.

Adult↗
PubMed1995

Neuropsychological slowness in obsessive-compulsive patients. Is it confined to tests involving the fronto-subcortical systems?

BACKGROUND: Although it is acknowledged that obsessive-compulsive (OC) patients may be slower than healthy controls in performing neuropsychological tests, speed has usually been treated as a confounding variable. It is possible, however, that the slower performance of OC patients is itself the result of a dysfunction of specific neural circuits (in particular of fronto-subcortical systems). METHOD: A neuropsychological battery including tests sensitive to fronto- and temporo-subcortical dysfunction was administered to a group of OC patients and a group of healthy controls. Each test provided independent indices of accuracy and speed. RESULTS: OC patients were significantly slower than controls only when performing tasks involving the fronto-subcortical systems, whereas they did not differ from controls with respect to accuracy indices. CONCLUSION: It may be that neuropsychological slowness of OC patients is not merely an epiphenomenon of meticulous concern for correct test execution or intrusion of obsessive thoughts, but reflects the dysfunction of fronto-subcortical systems.

Adolescent↗
PubMed1995

(+)-N-allylnormetazocine enhances N-acetyltransferase activity and melatonin synthesis: preliminary evidence for a functional role of sigma receptors in the rat pineal gland.

In the present study, to evaluate the role that sigma receptors play in the physiology of the pineal gland, we assessed the effects of the sigma receptor ligand (+)-N-allylnormetazocine on the gland activity during either the day or the night. As compared to saline, (+)-N-allylnormetazocine enhanced the physiological increases in both pineal N-acetyltransferase (NAT) activity and melatonin content at night, but it did not affect the biosynthetic activity of the gland during the day. Moreover, (+)-N-allylnormetazocine potentiated the enhancement of NAT activity and pineal melatonin content induced by isoproterenol administration during the day. The nocturnal stimulation of pineal NAT activity and melatonin levels by (+)-N-allylnormetazocine was prevented by pretreatment with rimcazole, a specific sigma receptor antagonist. These results demonstrate that sigma receptor activation by (+)-N-allylnormetazocine is not able, by itself, to stimulate pineal melatonin production, whereas it potentiates the biosynthetic activity of the pineal gland when this is stimulated noradrenergically.

Animals↗
PubMed1994

QEEG alpha 1 changes after a single dose of high-potency neuroleptics as a predictor of short-term response to treatment in schizophrenic patients.

Baseline quantitative electroencephalographic (QEEG) characteristics and their changes after a single test dose of either haloperidol or clopenthixol were investigated in a group of 29 schizophrenics as possible predictors of short-term response to those drugs. On baseline QEEG assessment, responders (R) to subsequent treatment showed fewer slow and more fast activities than nonresponders (NR). A large overlap between R and NR with respect to these measures was observed, however, revealing their practical inadequacy to predict short-term response in individual patients. On the contrary, changes in alpha 1, observed 6 hr after the administration of a single test dose of either haloperidol or clopenthixol, discriminated to a very large extent between R and NR, correctly identifying 17 out of 18 R and 8 out of 10 NR. The QEEG test dose procedure might be used in the selection of the most appropriate antipsychotic drug for individual schizophrenic patients.

Adolescent↗
PubMed1994

WHO Neuropsychiatric AIDS study, cross-sectional phase I. Study design and psychiatric findings.

BACKGROUND: Most available studies on the psychiatric, neuropsychological, and neurological complications of HIV-1 infection and AIDS have been conducted in Western countries, on samples of well-educated, mostly white, homosexual men. Concerns about generalizability of the results of those investigations prompted the WHO to implement the cross-cultural venture called WHO Neuropsychiatric AIDS study. METHODS: This project aims to assess the prevalence and natural history of HIV-1-associated psychiatric, neuropsychological, and neurological abnormalities in representative subject samples enrolled in the five geographic areas predominantly affected by the HIV-1 epidemic. Assessment is made by a data collection instrument including six modules. The intercenter and intracenter reliability in the use of each module has been formally evaluated. The study consists of a cross-sectional phase and a longitudinal follow-up. RESULTS: The cross-sectional phase was completed in five centers. This paper reports on the results of psychiatric assessment, which revealed a significantly higher prevalence of current mental disorders in symptomatic seropositive persons compared with seronegative controls among intravenous drug users in Bangkok and homosexuals/bisexuals in São Paulo. The mean global score on the Montgomery-Asberg Depression Rating Scale was significantly higher in symptomatic seropositive individuals than in matched seronegative controls in all centers. CONCLUSIONS: These results suggest that the significance of the psychopathological complications of symptomatic HIV-1 infection may have been underestimated by previous studies conducted on self-selected samples of well-educated, middle-class, mostly white, homosexual men.

AIDS Dementia Complex↗
PubMed1994

WHO Neuropsychiatric AIDS study, cross-sectional phase II. Neuropsychological and neurological findings.

BACKGROUND: The neuropsychological and neurological complications of HIV-1 infection and AIDS were explored within the cross-sectional phase of the WHO Neuropsychiatric AIDS Study. Special attention was devoted to the controversial issue of the prevalence and clinical significance of subtle cognitive deficits in asymptomatic seropositive subjects. METHODS: A neuropsychological test battery validated for cross-cultural use, a structured interview for the diagnosis of dementia, a rating scale of functioning in daily living activities, and a neurological module were administered to representative samples of seropositive subjects and to matched seronegative controls living in the five geographic areas predominantly affected by the HIV-1 epidemic. Data are available for five centers. RESULTS: The prevalence of global neuropsychological impairment was significantly increased in asymptomatic seropositive subjects compared with controls in only two centers. A significant effect of education on neuropsychological performance was observed among asymptomatic seropositive individuals. In the two African centers, low-education, but not high-education, asymptomatic seropositive persons had an impaired performance. The frequency of impaired functioning in daily living activities and of neurologic abnormalities was higher in symptomatic, but not in asymptomatic, seropositive subjects compared with controls in all centers. CONCLUSIONS: These data suggest that the risk of subtle cognitive deficits may be increased in asymptomatic stages of HIV-1 infection. However, these deficits are not associated with neurologic changes and do not seem to affect subjects' social functioning.

AIDS Dementia Complex↗
PubMed1994

Burden on key relatives of patients with schizophrenia vs neurotic disorders: a pilot study.

The burden perceived by the key relatives of 27 schizophrenics and 19 patients with neurotic disorders, both with at least a minimal degree of personal/social disability and a current exacerbation of symptoms, was assessed by a self-administered questionnaire. Only modest quantitative and qualitative differences between the two samples of key relatives were found. The burden perceived by the relatives of schizophrenics was more closely related to the patients' personal/social disability than that reported by the relatives of neurotic patients. The psychopathological features of schizophrenic patients that were perceived as the most burdensome were "negative" symptoms, whereas the burden reported by the relatives of neurotic patients was predominantly related to obsessive/compulsive and anxiety symptoms.

Adolescent↗
PubMed1994

Role of seizure activity in the decreased pineal response to isoproterenol in rats chronically treated with electroconvulsive shock.

Chronic electroconvulsive shock (ECS) has been previously reported to blunt the melatonin response to acute isoproterenol administration in rats. To assess whether electrically induced seizures are indeed required for the appearance of the blunted pineal response to isoproterenol, pineal and serum melatonin levels were measured after isoproterenol stimulation in rats treated with ECS (80 mA, 0.5 sec), subconvulsive shock (15 mA, 0.5 sec), or sham-ECS once per day at 11:30-12:00 h for 8 days. In ECS-treated rats, both pineal and serum melatonin levels after isoproterenol administration were significantly lower than those in sham-treated animals and in rats receiving subconvulsive shock. Moreover, as compared with sham treatment, chronic subconvulsive shock did not affect the melatonin response to isoproterenol. These data show that seizure activity is indeed required for the ECS-induced decrease in the pineal response to acute beta-adrenergic stimulation.

Animals↗