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Biomedical subjects

S Levine

Publications and source records attributed to S Levine.

At least 217 records · Page 12Linked to original sources
PubMed1991

Type of symptomatology as a form of volunteer bias.

We sought to explore the relationship between type of psychopathology and consent bias. Using the Brief Psychiatric Rating Scale we assessed a group of 48 forensic psychiatric inpatients. These patients were later independently approached by a researcher who attempted to get their consent for a study on the validity of self-reported criminal behavior. Thirty agreed to participate and 18 did not. The consenting patients were significantly younger and had significantly more negative symptoms than the nonconsenters. The difference in negative symptoms remained significant after age and medication dose, in chlorpromazine equivalents, were covaried out. The authors discuss the implications of these findings for forensic research.

Adult↗
PubMed1990

Ontogeny of mineralocorticoid (type 1) receptors in brain and pituitary: an in vivo autoradiographical study.

The ontogeny of high affinity [3H]corticosterone uptake and retention in brain and pituitary of 24-h adrenalectomized rats was examined using autoradiography of in vivo labeled brain sections. Our data indicate: (1) There is specific uptake of radiolabeled steroid in both brain and pituitary already at 2 days of age, following administration of a tracer (2 microCi/g body wt.) dose of [3H]corticosterone. This uptake is maximum around 4-8 days of age and decreases towards adult values around postnatal day 16. (2) High affinity uptake, at least in the brain, probably represents mostly binding to the mineralocorticoid receptor (MR) and not to the glucocorticoid receptor (GR), as it was not displaced by an excess dose of a GR antagonist, RU 38486, and its location in the hippocampus resembled that of MRs in the adult animal. The tracer amounts of [3H]corticosterone circulating after injection in the rat pups resulted in steroid levels comparable to basal levels of non-adrenalectomized animals of equivalent age. Thus, MRs may be the receptors mainly responsible for mediating physiological effects of glucocorticoids during early ontogeny.

Aging↗
PubMed1990

Opioid antagonist eliminates the stress-induced impairment of long-term potentiation (LTP).

Rats (n = 20) were injected with the opioid antagonist naltrexone and half were exposed to inescapable shock/restraint. Another 20 rats were injected with saline and half were exposed to shock. Neither saline nor naltrexone alone had any effect on hippocampal LTP. A large reduction in LTP was observed in saline rats exposed to shock, while normal LTP developed in the naltrexone rats exposed to shock. Thus, naltrexone eliminated the impairment, and thereby implicated endogenous opioids in the mechanism responsible for the stress-induced impairment of LTP.

Action Potentials↗
PubMed1990

Hypertensive black men and women. Quality of life and effects of antihypertensive medications. Black Hypertension Quality of Life Multicenter Trial Group.

A multicenter, randomized double-blind clinical trial was conducted among 306 black men and women with mild to moderate hypertension to determine effects of atenolol, captopril, and verapamil SR on measures of quality of life. Patients were randomly assigned to a stable or forced-dose titration sequence. After an 8-week treatment period, the rate of withdrawal from treatment because of adverse effects was low and did not differ by drug treatment group or titration level. Patients taking verapamil SR showed a significantly greater reduction in mean blood pressures than patients treated with atenolol or captopril. Along with absence of worsening on any quality of life total scale scores examined over the treatment period, we found either improvement or no change in the total scale scores for all three treatment groups. Among both male and female patients, comparisons between drug treatment groups showed no differences in degree of change on the total scale scores. In comparisons within each treatment group, improvement in scores of male patients after 8 weeks appeared among those taking atenolol in general well-being and physical symptoms reduction; among male patients taking captopril in general well-being, physical symptoms, and sexual performance; and among male patients receiving verapamil SR in scores in irritability, sleep, and the Digit Span test. Improvement in scores among female patients taking atenolol was found in scores on general well-being, physical symptoms, and sleep; among women taking captopril on general well-being, physical symptoms, and irritability; and among women taking verapamil SR on general well-being. Patients in all treatment groups improved on measures of visuomotor functioning. The research shows that with the three newer generation antihypertensive medications studied, blood pressure control was achieved during the treatment period without negative effects on quality of life scales, along with findings of improvement on some measures. Given the special clinical features of hypertension in black patients, the study underlines as well the potential and utility of systematic tracking of measures of quality of life, while monitoring blood pressures in this patient population.

Black or African American↗
PubMed1990

Inhibition of infant glucocorticoid stress response: specific role of maternal cues.

Previous work from this laboratory has shown that passive contact with an anesthetized lactating dam eliminates the corticosteroid stress response to novelty in 12-, 16-, and 20-day-old rat pups. In the present study, we further examined some of the sensory and developmental aspects of this phenomenon. In two experiments, we asked whether inhibition of the corticosteroid stress response is related exclusively to contact with a maternal stimulus as opposed to other social stimuli. Experiment I compared the effectiveness of contact with an anesthetized dam vs, an anesthetized adult male rat. At 12 and 16 days of age, contact with an adult male was somewhat effective in reducing stress responsiveness, whereas at 20 days, contact with an adult male was entirely ineffective. At all ages, contact with an anesthetized dam was an effective inhibitor of the stress response. Experiment II compared the relative effectiveness of contact with an anesthetized dam vs. an anesthetized sibling pup. At all ages, contact with a dam was very effective, whereas contact with an anesthetized pup was entirely ineffective in inhibiting the glucocorticoid stress response. In Experiment III, the effect of maternal contact was assessed during a period of development when the biological, and presumably social, significance of the lactating-dam stimulus is changing. In this study, 20-, 24-, and 28-day-old rat pups revealed a progressive decrement in the ability of maternal contact to inhibit stress responsiveness. These findings replicate and extend our previous ones by showing that maternal stimuli play a special role in the modulation of pituitary-adrenal activity during development.

Animals↗
PubMed1990

Unpredictable and uncontrollable stress impairs neuronal plasticity in the rat hippocampus.

Almost by definition, learning and the effect of stress on learning represent modifications of existing neuronal circuitry. Under some circumstances, this modification can be measured electrophysiologically. One such measure of plasticity is long-term potentiation (LTP), a long-lasting increase in synaptic efficacy following brief exposure to tetanic stimulation. In 1987, Foy et al. reported that hippocampal LTP was impaired by exposure to inescapable shock. We have recent evidence that the impairment in LTP can be prevented by allowing the animal to learn to escape the shock (Shors et al., 1989), indicating that the stress effect is to some extent mediated by "psychological" variables. Regardless of LTP's putative role in learning and memory processes, such a stress-induced decrease in neuronal plasticity is likely to have profound effects on the behaving organism.

Adaptation, Physiological↗
PubMed1990

Impact of perceived self-efficacy in coping with stressors on components of the immune system.

This experiment examined the impact of experimentally varied perceived self-efficacy in exercising control over stressors on components of the immunological system. Immunological changes while coping with phobic stressors were measured within an intrasubject control design that included a baseline phase, an efficacy-acquisition phase, and a maximal-efficacy phase. In each of these phases, perceived coping self-efficacy, level of autonomic and endocrine activation, and several components of the immunological system were measured. Development of strong perceived self-efficacy to control phobic stressors had an immunoenhancing effect. A slow growth of perceived self-efficacy, heart rate acceleration, and cortisol activation attenuated immunological system status during the efficacy-acquisition phase. Rapid growth of perceived self-efficacy also predicted maintenance of immunoenhancement during the maximal perceived self-efficacy phase.

Adaptation, Psychological↗
PubMed1990

Behavioral and physiological responses to maternal separation in squirrel monkeys (Saimiri sciureus).

This study extends an examination of the behavioral and pituitary-adrenal responses of infant squirrel monkeys (Saimiri sciureus) separated from their mothers under different environmental conditions to another physiological system by measuring the metabolites of the central monoamines found in the cerebrospinal fluid (CSF). This study included spectrographic examination of the vocalizations emitted by the infant during separation. Infants were separated from their mothers for 24 hr under 3 conditions: Home, infant remained in its home cage after removal of mother; adjacent, infant was placed in a cage adjacent to its mother; and total, infant was totally isolated. The behavioral results indicated that the number of calls emitted differed with condition (adjacent greater than total greater than home), and the peak frequency of the calls and number of multiple calls was greatest in the total condition. Plasma cortisol elevations after separation differentiated the conditions of separation (total greater than adjacent greater than home greater than base). The elevations in the CSF catecholamine metabolites (3-methoxy-4-hydroxyphenylglycol and homovanillic acid) were also sensitive to the conditions of separation (total greater than adjacent greater than base). These results are discussed in the context of coping theory.

Animals↗
PubMed1990

Prediction of lactate threshold (LT) and fixed blood lactate concentrations (FBLC) from 3200-m running performance in women.

The present study evaluated the accuracy of predicting velocity and oxygen consumption (VO2) at the LT lactate threshold and FBLC fixed blood lactate concentrations from a 3200-m time trial in women. Forty-four women (mean age = 31.1 yrs, mean ht = 164.9 cm, mean wt = 65.0 kg) completed a treadmill protocol for the determination of LT and FBLC and a 3200-m time trial. Velocity and VO2 values at LT, FBLC of 2.0 2.5, and 4.0 mM, and peak were determined. Mean VO2 and velocity ranged from 27.8 +/- 10.8 ml/kg.min-1 at LT to 42.5 ml/kg.min-1 at peak and from 129.8 +/- 44.0 m.min-1 at LT to 187.0 +/- 52.4 m.min-1 at peak, respectively. Results indicated that a 3200-m time trial (mean time = 20.6 +/- 6.6 min) was a good predictor of VO2 and velocity at LT, FBLC, and peak. Correlation coefficients (using a quadratic model) for velocity ranged from R = 0.96 to R = 0.98 with SEE ranging from 9.0 to 13.1 m.min-1. Correlation coefficients for VO2 ranged from R = 0.94 to R = 0.96 with SEE ranging from 2.8 to 3.6 ml/kg.min. The validity of these regression equations was examined in 13 women who completed a 12-month running program (VO2 LT, VO2 at FBLC of 2.0, 2.5 and 4.0 mM, and VO2 peak increased by 34.7, 19.9, 16.9, 11.9, and 5.4%, respectively, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Self-reported side effects from antihypertensive drugs. A clinical trial. Quality of Life Research Group.

We report on the distress associated with physical symptoms in 761 male hypertensive patients enrolled in a clinical trial of the effects of captopril, methyldopa or propranolol on quality of life. Educational level at entry into the trial showed a negative association with a series of physical symptom distress items among patients not previously treated with antihypertensive medications but no association with symptoms among the previously treated. Over the 24 weeks of therapy captopril as monotherapy was associated with no change from baseline in distress in all symptoms examined. In contrast, distress increased in the methyldopa treated patients for dry mouth and blurred vision. Propranolol treated patients had increased "trouble getting breath," bradycardia, shortness of breath or wheezing, and blurred vision. Between group comparisons revealed significant differences favorably comparing captopril to both methyldopa and propranolol in regard to fatigue, and blurred vision, as well as to methyldopa alone for dry mouth and "feeling worn out." There were significant differences as well between captopril and propranolol with patients on propranolol worsening in bradycardia. Other comparisons of patients on propranolol and methyldopa monotherapy showed propranolol patients worsening in bradycardia and loss of taste, but methyldopa patients reported more dry mouth and feeling worn out than those on propranolol. The addition of hydrochlorothiazide to therapy worsened total physical symptom distress scores for methyldopa and propranolol patients. This study confirms the value of methods which assess the degree of distress associated with symptoms commonly reported by hypertensive patients receiving antihypertensive medications. This approach can be useful in establishing a treatment regimen least likely to cause distress and can be of value in preserving quality of life, preventing noncompliance, and withdrawal from treatment.

Adult↗
PubMed1990

Encephalitogenicity for rats of myelin basic protein without the aid of water-in-oil emulsions.

The induction of experimental allergic encephalomyelitis (EAE) with purified myelin basic protein (MBP) has, heretofore, required its incorporation in a water-in-oil emulsion or adsorption on particulate adjuvants. In the present work, the absorption of a saline solution of MBP from the peritoneal cavity into the mediastinal lymph nodes was increased by giving repeated inoculations or by pretreating rats with a peritoneal irritant. Under these conditions, the only adjuvant needed for production of EAE was aqueous pertussis vaccine which was injected separately a few hours or one day after the MBP. Pertussis vaccine was also necessary for production of EAE with intradermal injection of aqueous MBP. By injecting the aqueous MBP directly into pre-enlarged popliteal lymph nodes, it was possible to produce EAE without the pertussis vaccine. Thus, EAE can be induced in rats using MBP without the addition of Freund's adjuvant or pertussis vaccine.

Animals↗
PubMed1990

New drug treatment for diarrhoea.

This paper reviews the scientific background to the development of new drugs for the treatment of diarrhoeal diseases, and it includes an update of three classes of drugs which may prove useful; gut specific alpha2-adrenergic agonists, intestinal Cl- channel blockers, and somatostatin analogues.

Animals↗
PubMed1990

Remoxipride and haloperidol in the acute phase of schizophrenia: a double-blind comparison.

The efficacy and safety of remoxipride in the treatment of schizophrenia were compared with those of haloperidol in a multicentre double-blind 6-week study which was randomized with a parallel group design and was preceded by a washout period. Eighty-nine consecutively admitted men and women meeting the Research Diagnostic Criteria for schizophrenia in an acute phase of the illness were treated with remoxipride 75-300 mg twice daily or haloperidol 5-20 mg twice daily. The efficacy assessments were the Brief Psychiatric Rating Scale, Krawiecka Rating Scale, and Clinical Global Impression. Both antipsychotic drugs produced clinical improvement with no significant differences between the efficacy of the two drugs. There were relatively few side effects. There were significantly fewer extrapyramidal symptoms and instances of blurred vision with remoxipride and less constipation with haloperidol. The results indicate that remoxipride is as effective an antipsychotic as haloperidol. Remoxipride has an advantage over haloperidol in respect to extrapyramidal side effects.

Acute Disease↗
PubMed1990

Effect of adrenalectomy and demedullation on the stress-induced impairment of long-term potentiation.

In these three experiments, we investigated the effect of adrenalectomy and adrenal demedullation on the stress-induced impairment of long-term potentiation (LTP) in the rat hippocampal slice. In the first, adrenalectomy alone resulted in a significant reduction in LTP, while exposure to stress resulted in a further reduction. In the second, replacing corticosterone in adrenalectomized rats did not restore LTP. In the last experiment, demedullation resulted in a reduction in LTP similar to that induced by adrenalectomy, while exposure to stress did not result in a further reduction. In combination, these studies provide evidence that the adrenal medullary system modulates hippocampal plasticity and the stress-induced impairment of LTP.

Adrenal Glands↗
PubMed1990

Influence of maternal proximity on behavioral and physiological responses to separation in infant rhesus monkeys (Macaca mulatta).

The effects of maternal proximity on the behavioral and physiological responses of infant rhesus macaques during 4 days of total or adjacent separations from the mother were studied. The 6 infants tested showed behavioral responses that differentiated the two separation conditions. Major differences were found in the quantity and quality of vocalizations, the occurrence of cage-biting and cage-shaking behavior, object exploration, and hunched and freezing postures. In particular, the structure of coo vocalizations clearly discriminated between the presence or the absence of the mother during separation. Cerebrospinal fluid (CSF) concentrations of dopamine and serotonin metabolites did not discriminate between the two separation conditions but showed a transient elevation at 24 hr after separation and were not different from baseline by 96 hr after separation. In contrast, both the plasma cortisol and the CSF norepinephrine metabolite responses tended to be greater and to persist for a longer period of time when infants were totally isolated. The results are discussed within the context of attachment and coping theories.

Animals↗
PubMed1990

Peptides of myelin basic protein are encephalitogenic in rats without the aid of emulsions.

Immunization with peptides is usually done with the aid of Freund's adjuvant. Using peptides derived from myelin basic protein, we show that aqueous solutions can be antigenic (encephalitogenic in this instance) in Lewis rats. The first procedure involved multiple doses of aqueous peptide, increased absorption into the lymphatic system from the peritoneal cavity in the postinflammatory state, and the use of pertussis vaccine. Three different peptides containing the major encephalitogenic site were active in this system, with the activity somewhat proportional to the size of the fragment. The second procedure, the direct delivery of peptide to lymph nodes by percutaneous inoculation, was equally successful and did not require the use of pertussis vaccine.

Absorption↗
PubMed1990

Anomalous serum thyroxin measurements with the Abbott TDx procedure.

We describe a patient whose serum gave consistently low results for thyroxin as measured with the Abbott TDx but normal results by radioimmunoassay. Further clinical and laboratory studies did not support the low TDx results. Anti-thyroxin antibodies did not explain the discordant results, and we found no evidence of heterophilic antibodies in the patient's serum. We were unable to identify the cause of the problem.

Adult↗