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Biomedical subjects

R Levin

Publications and source records attributed to R Levin.

At least 55 records · Page 3Linked to original sources
PubMed1985

Ventricular fibrillation in a tetraplegic patient who had a therapeutic level of a tricyclic antidepressant. Case report.

A case is presented of a young, chronic tetraplegic patient who, shortly after achieving therapeutic levels of imipramine, a tricyclic antidepressant (TCA) developed a life-threatening ventricular arrhythmia. Since tetraplegic patients frequently manifest evidence of autonomic supersensitivity, the autonomic effects of the TCA may have led to the cardiac arrhythmia. Caution should be exercised in the use of TCA's in tetraplegic patients.

Adult↗
PubMed1984

The diagnosis and management of renal inflammatory processes in children.

Renal inflammatory processes in children often present a diagnostic and therapeutic dilemma. Since the advent of improved diagnostic imaging techniques these lesions can be appreciated and defined better. An analysis of 12 children with renal inflammatory lesions treated at our institution clearly outlines the pathological spectrum of these lesions and provides a format for their diagnosis and management.

Abscess↗
PubMed1984

Human vaginal pH and sexual arousal.

The surface pH of the vagina was measured before and after sexual arousal by self-stimulation in ten healthy women. The mean value of six spots measured and pH measured in collected vaginal fluid was highly correlated. Two-way analysis of variance showed a mean increase of pH after orgasm (significant at the 0.5% level). The Wilcoxon matched-pairs test and a paired t-test showed a significant increase in three and four of the subjects, respectively, and a decrease in pH in one other subject. It is concluded that in the present laboratory setting, clitoral self-stimulation to orgasm only results in small changes of the vaginal surface pH.

Adult↗
PubMed1981

Sperm function in affective illness.

There is evidence for functional changes in the hypothalamic-pituitary-gonadal axis of patients with affective disorders. Little is known concerning spermatogenesis or sperm function in depressed men. We systematically evaluated the sperm indices in a group of depressed males complaining of diminished libido, and a healthy control group. No differences were noted in sperm parameters between the groups.

Adult↗
PubMed1981

Pleural plaques and cigarette smoking in asbestos workers.

In a survey of 45 men aged 40 or over who had worked five years or more in an asbestos manufacturing plant, the prevalence of pleural plaques was studied with respect to age, duration of asbestos exposure, estimated cumulative asbestos dose, and smoking habit. Plaques were found in 38 to 53% of the men, depending on the interpretation of the chest film reader. Cigarette habit appeared to be the most important factor; the prevalence was lowest in non-smokers, intermediate in current smokers, and particularly high in exsmokers. There was some confounding of this relationship by estimated cumulative asbestos dose but such confounding did not seem to be sufficient to explain fully the relationship between the prevalence of plaques and smoking habit. Both factors must be considered in studies of the risk of pleural plaques in asbestos workers.

Adult↗
PubMed1978

Oxygen tension of the vaginal surface during sexual stimulation in the human.

An oxygen electrode was maintained by suction on the vaginal wall in seven women. The basal value of pO2 was 9.3 mm Hg +/- 10.7 (mean +/- standard deviation) before clitoral self-stimulation was initiated. When stimulation took place the oxygen tension rose and peaked immediately after orgasm to 39.5 +/- 14.1 mm Hg. It then declined and fell to 20.1 +/- 13.8 mm Hg 10 minutes after the peak value. The changes correlate closely with changes in vaginal blood flow. The increased oxygen tension may be one of the factors that enhance of even initiate the motility of spermatozoa when deposited intravaginally.

Adult↗
PubMed1978

Comparison of the effects of restricted morning or evening water intake on adrenocortical activity in female rats.

The effects of restricting daily water intake to either a 30-min morning or evening period were investigated on: (1) the overall circadian pattern of adrenocortical activity, and (2) adrenocortical activity during the 20-min period immediately after water presentation. Morning water restriction produced a substantial increase in pre-water levels of circulating corticosterone without affecting evening levels, thereby changing the form of the circadian pattern. In contrast, evening water restriction did not elicit any pre-water increase in corticosterone levels, and there was no change in the circadian pattern. Both morning and evening water restricted animals showed a pronounced and rapid decline in corticosterone levels during the 20-min post-water period, with levels dropping by more than 50% within 10 min of water presentation. The dissociation of the pre-water elevation and post-water decline in corticosterone evident in evening water animals indicates that these 2 processes may be governed by different factors. It is suggested that the pre-water effect involves circadian regulatory mechanisms whereas the post-water effect is associated with the process of reinforcement.

Adrenal Cortex↗
PubMed1977

Alterations in the maternal behavior of rats rearing malnourished offspring.

Investigations of maternal behavior of mothers fed a low-protein diet indicated deficits in retrieval and in the rate of nest-building. In addition, they indicated a concomitant increase in time spent with young when assessed during periods not associated with the retrieval/nest-building test session. The adrenalectomized mother, another case that produces growth-stunted progeny, was compared with both low-protein and control mothers for maternal behavior. Unlike the low-protein mother, the adrenalectomized mother did not exhibit retrieval or nest-building deficits; however, the adrenalectomized mother did display an increase in time spent with young. These data suggest that although deficits in retrieval and nest-building can be attributed to the nutritional condition of the mother, the stimulus characteristics of the malnourished pup are important in eliciting the increased time spent with the litter.

Adrenalectomy↗
PubMed1977

Influence of experiential factors and gonadal hormones on pituitary-adrenal response of the mouse to novelty and electric shock.

Plasma corticosterone elevations have been shown to occur in response to exposure to a novel environment and to the delivery of painful stimulation, such as footshock. The present experiment investigated the effects of experience with these types of stimuli upon the responsivity of the pituitary-adrenal system. When mice were subjected to repeated footshock, the adrenocortical response was increased. When animals were repeatedly shocked in a specific environment, the adrenocortical-stimulating properties of the situational stimuli were also elevated. On the other hand, plasma corticosterone elevations in response to merely being placed in an experimental chamber were not affected by 10 exposures to the situation. Previous data showed that animals that had been shocked in one environment were generally more responsive to many types of stimulus changes. Such a pattern of results suggests that the pituitary-adrenal system is subject to sensitization processes and that the central nervous system substrate which controls its function is one that is normally involved with the production of states of arousal. This configuration of results was quite pronounced in the female mouse regardless of hormonal state, and it was absent in the intact male. The results of studies with gonadectomized males suggested that testosterone inhibits sensitization.

Animals↗
PubMed1976

Expression of feline type-C virus in normal and tumor tissues of the domestic cat.

Tumor and normal tissues from domestic cats were examined for FeLV and RD-114 specific nucleic acids and proteins. Virus-positive tissues showed a 100- to 200-fold higher level of FeLV and a 200- to 400-fold higher level of FeLV p30 than virus-negative tumors and normal cat tissues. In contrast, the levels of RD-114 viral RNA and p30 antigen were comparable in the majority of tumorous and normal tissues examined. When the DNA of these tissues was examined for FeLV-related sequences, the virus-positive tumors were found to contain extra copies of FeLV DNA. Virus-negative tumors contained DNA sequences homologous with FeLV but the copy number of these sequences could not be distinguished from normal tissues. The results indicate that in certain FeLV-induced type-C lymphoproliferative diseases, extra type-C sequences not present in normal tissues can be identified.

Animals↗
PubMed1976

Food availability as a determinant of the rats' circadian rhythm in maternal behavior.

Thre present study was designed to determine whether environmental factors other than light would alter the dialy periodicity in the rat's maternal behavior and whether such a change in the dam's behavior pattern would in turn alter the pattern of her sucklings' milk intake. Experiment 1 determined the daily pattern of litter weight gain (which presumably reflects milk intake) displayed by young reared by dams fed and watered either ad lib (Group C), only during the day (Group D), or only at night (Group N). Experiment 2 compared nocturnal and diurnal frequency of maternal behavior in Groups C, D, and N. The pattern of both litter weight gain and maternal behavior was observed to be diurnal in Groups C and N and nocturnal in Group D.

Animals↗