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Biomedical subjects

S Feldman

Publications and source records attributed to S Feldman.

At least 199 records · Page 11Linked to original sources

An 11-year follow-up study of 110 depressed patients.

In 1972 the World Health Organization organized a cross-cultural five-centre study of depressive disorders. This report is concerned with data collected, after an 11-year follow-up period, in the sample of 110 depressed patients in Montreal, Canada. Eighty-five percent were traced and 59% were interviewed. Of 93 patients, 20 were dead at the follow-up date, 11 by suicide. Fifty-two percent of patients were receiving psychiatric treatment at follow-up, but there was no relation between psychiatric morbidity and treatment-seeking. Moderate or severe impairment of social functioning was present in 32%; in women, a trend linking the presence of social impairment and the time spent in episodes was observed. Of the episodes of psychiatric illness recorded after the index episode, 86% were diagnosed as depressive, 14% as unspecified affective disorder. The mean durations of the index and four subsequent episodes were 10, 11, 7, 11, and 2 months respectively. At least one recurrence after the index episode was reported by 78%, at least four recurrences by 19%. Episodes lasted at least one year in 5%, 4%, 6%, and 6% in the first, second, third and fourth episodes respectively. Sixteen percent were depressed for at least one year and 31% for at least 2 years. There was a marked trend from inpatient to outpatient treatment and from ECT to drug therapy over time. Twenty-two percent reported either moderate or severe problems with alcohol or substance abuse. There was a statistically significant association between the amount of time patients spent in depressive episodes and the number of life events they reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Subcortical pathways involved in the mediation of adrenocortical responses following frontal cortex stimulation.

The purpose of this study was to identify the subcortical neural pathways which mediate adrenocortical responses following cortical stimulation. The frontal cortex was stimulated in intact rats and in animals with medial or lateral septal or preoptic lesions or with large or small anterior hypothalamic deafferentations. All the above-mentioned lesions have significantly blocked the adrenocortical responses following frontal cortex stimulation, suggesting that the above-mentioned subcortical structures are involved in the mediation of this response.

Animals↗

Neural pathways that mediate the effects of afferent stimuli on paraventricular nucleus multiunit activity in freely moving rats.

The direct involvement of the hypothalamic paraventricular nucleus (PVN) in the control of adrenocortical secretion is now generally accepted. In order to contribute to our understanding of the electrical activity of cells in this region during adrenocortical activation, we have recorded multiunit electrical activity (MUA) in response to acute neural stimuli in freely moving male rats and have examined the pathways involved. Photic, acoustic, olfactory, and sciatic nerve stimulation all increased PVN MUA by between 130% and 250%. These responses were selectively blocked, according to the stimulus modality tested, by radiofrequency lesions of central neural structures. Thus PVN responses to photic stimulation were blocked by lesions of the suprachiasmatic nuclei and reduced by mammillary peduncle lesions but were unaffected by lesions of the bed nuclei of the stria terminalis. Responses to acoustic stimulation were blocked by lesions of the mammillary peduncles but not by those placed in the suprachiasmatic nuclei, the septum, or the bed nuclei of the stria terminalis. Lesions of the septum blocked the response to sciatic nerve stimulation but did not affect the response to olfactory stimulation with amyl acetate fumes, which was blocked by lesions of the bed nuclei of the stria terminalis. The data confirm those obtained in endocrine studies concerning the neural pathways involved in the transmission of neural stimuli that produce adrenocortical activation.

Acoustic Stimulation↗

Electrophysiology of supraoptico-paraventricular nucleus connections in the rat.

In an attempt to clarify the mechanisms involved during synchronous discharge of magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, extracellular action potentials were recorded from 149 single units located in the rat paraventricular nucleus. Responses of the cells to stimulation of the ipsilateral supraoptic nucleus were recorded and it was observed that 7% of paraventricular nucleus neurones could be antidromically identified as projecting to the supraoptic nucleus. Excitatory responses were recorded from 40% of cells tested and were probably mediated by an interneurone population. Inhibitory responses were recorded from 37% of the cells and may have been mediated by direct projections from the supraoptic nucleus. No differences in responses were recorded from cells identified as projecting to the median eminence or neurohypophysis as compared with the rest of the population tested. However, more of the phasically firing putative vasopressin-secreting cells, (58%) were excited than were continuously active cells (38%). Delivery of short trains of high-frequency stimulation induced bursts of discharge from 93% of cells so tested, regardless of response to single shock stimulation. These burst discharges showed a late onset as compared with responses following single shock stimulation. The results suggest that a complex of intra- and internuclear interactions serve to regulate the neurosecretory activity of magnocellular cells within the supraoptic and paraventricular nuclei.

Action Potentials↗

Hypothalamic afferent connections mediating adrenocortical responses that follow hippocampal stimulation.

This study identified some neural pathways which mediate the adrenocortical responses that follow hippocampal stimulation. The increase in plasma corticosterone following dorsal hippocampus stimulation, in rats with electrodes chronically implanted under pentobarbital anesthesia, was blocked by dorsal fornix and lateral septal lesions and by small posterior hypothalamic deafferentation. Fimbria transection, lateral septal lesions, and posterior hypothalamic deafferentation, but not midbrain reticular formation lesions, also blocked the adrenocortical responses to ventral hippocampus stimulation. Our present and previous studies indicate that the dorsal and ventral hippocampal effects on the hypothalamus, which increase plasma corticosterone concentrations, are mediated by the dorsal fornix and fimbria, respectively, as well as by the lateral septum. A posterior hypothalamic input, which does not involve the medial forebrain bundle or the midbrain reticular formation is also essential for the activation of this response.

Adrenal Cortex↗

Effects of septal and hippocampal stimuli on paraventricular nucleus neurons.

The electrical activity of 125 neurons within the hypothalamic paraventricular nucleus was recorded in urethan-anaesthetized male rats. Spontaneous activity of the cells and their responses following electrical stimuli delivered to the ipsilateral lateral septum and dorsal hippocampus were recorded. The mean firing rate of all the cells recorded was 3.5 +/- 0.4 Hz and the majority were located within the dorsal and medial components of the paraventricular nucleus. Forty-six percent of the cells were inhibited following stimulation of the lateral septum (onset, 22.8 +/- 6.7 ms; offset, 195.1 +/- 28.5 ms). Inhibitory responses to dorsal hippocampus stimulation were recorded from 44% of all cells (onset, 28.1 +/- 4.7 ms; offset, 180.7 +/- 28.7 ms). Stimulation of both sites caused excitation of equal proportions (26%) of the cells tested (lateral septum onset, 47.7 +/- 4.5 ms; offset, 64.8 +/- 6.6 ms; dorsal hippocampus onset, 48.7 +/- 5.6 ms; offset, 72.3 +/- 8.8 ms). Of the sub-population of cells identified as projecting to the median eminence, inhibition was recorded from 50% following lateral septum stimulation and 43% following dorsal hippocampus stimulation, excitatory responses being recorded from only 9% of cells tested. The excitatory responses were only recorded from phasically firing, vasopressin-secreting cells identified as projecting to the median eminence, and also to the neurohypophysis. Following stimulation of either site, more phasic cells were excited whilst only few were inhibited. Continuously active cells, identified as projecting to the neurohypophysis, showed more mixed responses following stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗

Paraventricular nucleus serotonin mediates neurally stimulated adrenocortical secretion.

The purpose of this study was to further elucidate the role of serotonin (5-HT) in adrenocortical regulation. The effects of stimulating the frontal cortex and extrahypothalamic limbic structures, on plasma corticosterone (CS) responses, were studied in rats with vehicle or 5,7-dihydroxytryptamine (5,7-DHT) injection into the midbrain raphe nuclei. In another group of rats the neurotoxin was injected locally into the paraventricular nucleus (PVN) in view of its importance in adrenocortical regulation, and the effects of photic and dorsal hippocampal stimulation on plasma CS were studied. 5,7-DHT caused a significant depletion of hypothalamic 5-HT and blocked the rise in plasma CS following the stimulation of the above neural modalities. These studies suggest that the PVN 5-HT mediates the adrenocortical responses following afferent neural stimuli.

5,7-Dihydroxytryptamine↗

Efficacy of benzathine penicillin G in group A streptococcal pharyngitis: reevaluation.

The rate of streptococcal eradication after intramuscular administration of benzathine penicillin G in 66 children with acute group A streptococcal pharyngitis was determined and possible reasons for treatment failure explored. Bacteriologic treatment failure, defined as isolation of the same serotype at 3- or 6-weeks follow-up, occurred in eight (12%) patients. The treatment failure rate was 21% in those with immunologically significant infection, versus 8% in those without antibody rises (P greater than 0.1). All group A beta-hemolytic streptococcal (GABS) strains isolated from patients with treatment failure, both before and after benzathine penicillin G therapy, were exquisitely susceptible to penicillin G (minimum inhibitory concentration less than or equal to 0.02 microgram/mL), and none showed evidence of tolerance (minimum bactericidal concentration less than or equal to 0.04 microgram/mL). Thus, we found GABS eradication rates to exceed 10% in children given benzathine penicillin G. The failure rate did not appear to be related to enrichment of the patient population with a high proportion of asymptomatic carriers nor to the presence of penicillin-tolerant GABS.

Child↗

Pharmacokinetics of the acyclureidopenicillins piperacillin and mezlocillin in the postpartum patient.

The postpartum patient experiences numerous physiologic alterations, which may affect the pharmacokinetics of certain drugs. Six patients received either piperacillin or mezlocillin intravenously immediately after delivery. Serum half-life and clearance were, respectively, 82.4 min and 202 +/- 105 ml/min for mezlocillin and 32.9 min and 456 +/- 88 ml/min for piperacillin. The data revealed that mezlocillin and piperacillin have significantly different pharmacokinetic reactions in the postpartum patient at the doses used.

Chromatography, High Pressure Liquid↗

Overpopulation as crisis: redirecting health care services in rural Bangladesh.

This article examines the consequences of a "population-as-crisis" theme on the institutional configuration and resource endowments of health care services in an integrated Ministry of Health and Population Control in Bangladesh. The Ministry's focus on women as child bearers and its emphasis on sterilization supported by incentives has contradictory consequences as women become vulnerable to a limited health service and incentives encourage a focus on meeting sterilization targets. Both undermine people's access to and use of primary health care services. Findings from three studies, undertaken between 1978 and 1983, support the argument that despite international concern with preventive and promotive primary health care, simultaneous support for and emphasis on population control inhibits meeting the goals of a broad-based rural primary health care service.

Bangladesh↗

Varicella in children with cancer: impact of antiviral therapy and prophylaxis.

To estimate the impact of antiviral therapy and prophylaxis on the natural course of the infection, 288 cases of varicella in children with cancer were reviewed. Among 127 patients with untreated infections, the overall mortality rate was 7%. Varicella-zoster virus pneumonitis developed in 28% of the untreated patients and was associated with a 25% mortality rate. Pneumonitis was much more likely to develop in patients with acute leukemia than in those with other malignancies (32% v 19%). Similarly, deaths due to pneumonitis were restricted to patients with acute leukemia. Lymphopenia (absolute lymphocyte count less than 500/microL) was significantly associated with varicella-zoster virus pneumonitis and a higher fatality rate among patients with this complication. Both acyclovir and adenine arabinoside, administered to 18 and 28 patients, respectively, stopped the progression of skin lesions; however, pneumonitis developed in none of the acyclovir recipients after two days of treatment, compared with 29% of the adenine arabinoside recipients (P = .03). Passive immunization in 45 children who subsequently had varicella was associated with an 11% incidence of varicella-zoster virus pneumonitis. Despite passive immunization of approximately 150 children, the attack rate of varicella at our institution remains unchanged. Results of this study demonstrate the efficacy of antiviral therapy and passive immunization in patients with childhood cancer and varicella, but prevention of the infection will require a universal vaccine.

Antiviral Agents↗

Varicella zoster and herpes simplex virus pneumonias.

Varicella zoster (VZV) and herpes simplex (HSV) viruses commonly cause self-limited infection of the skin and mucous membranes. However, certain groups of subjects, including neonates, cancer patients, organ and bone marrow transplant recipients and those with congenital or acquired deficiencies of cell mediated immunity, are at increased risk for dissemination of either virus to the lungs and/or other viscera. The highest risk for VZV pneumonitis is in bone marrow transplant recipients, 44%, and in children with acute leukemia, 32%. The mortality from this complication of VZV infection in the preantiviral era was at least 25%. Except for neonates, dissemination and mortality rates for HSV infections are less than for VZV infections in the high risk groups. Cell-mediated immunity has a major role in both recovery from primary infection and modulation of latent infection, but antiherpes antibodies also have an important role in moderating the extent and severity of infection. Both viruses cause a patchy nodular pneumonia with scattered necrotic and hemorrhagic foci. Physical examination is often misleading and rapid progression of pneumonia can occur within hours. Intravenous acyclovir, administered early in the course of HSV and VZV infection at dosages of 250 mg/m2 and 500 mg/m2 every eight hours, respectively, has nearly eliminated the risk of severe symptomatic pneumonitis. Treatment of established pneumonitis with acyclovir at these doses has also reduced the mortality of herpesvirus pneumonias.

Adult↗

Evaluation for endotoxemia in patients receiving penicillin therapy for secondary syphilis.

To determine if endotoxin liberation occurs after antibiotic administration to patients with syphilis, serial plasma samples were obtained from 15 patients receiving intramuscular penicillin G benzathine for secondary syphilis. The endotoxin content of these plasma samples was determined using a Limulus lysate assay (detection limit, 0.025 ng of reference Escherichia coli endotoxin per milliliter of patient plasma). Although secondary syphilis is the stage of syphilis having the greatest burden of spirochetes and the highest incidence of Jarisch-Herxheimer reactions, no endotoxin was detected in plasma either before or after antibiotic therapy. Despite the absence of detectable endotoxemia, five patients experienced mild Jarisch-Herxheimer-like reactions. These results suggest that endotoxin is not an important factor in either secondary syphilis or the reactions associated with antibiotic therapy of this disease.

Adult↗

Norepinephrine depletion in the paraventricular nucleus inhibits the adrenocortical responses to neural stimuli.

In view of the importance of teh paraventricular nuclei of the hypothalamus (PVN) in the regulation of adrenocortical secretion and the possible role of norepinephrine (NE) in this mechanism, we have studied the effects of injecting the catecholamine neurotoxin 6-hydroxydopamine into the PVN on basal corticosterone (CS) secretion and following ether stress and neural stimuli. PVN NE depletion did not affect the basal and the ether stress-induced rise in CS levels. However, it inhibited significantly the adrenal response to photic, acoustic and sciatic nerve stimulation, suggesting that the PVN NE plays a role in the activation of adrenocortical responses following afferent neural stimuli.

Acoustic Stimulation↗