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Biomedical subjects

S Levine

Publications and source records attributed to S Levine.

At least 127 records · Page 7Linked to original sources
PubMed1996

Employee attitudes toward work-site alcohol testing.

Few studies have been published on how employees feel about work-site alcohol testing. By mail, we surveyed employees (n = 6370) at 16 corporate work sites stratified by type of work force, industrial setting, and managerial tolerance toward drinking. We queried respondents about their drinking on the job and support for work-site alcohol testing under three conditions: pre-employment testing, testing after an accident, and random testing. Sixty-five percent of respondents supported pre-employment testing, 81% supported testing after an accident, and 49% supported random testing. Support was relatively consistent across hierarchy (managers, supervisors, and workers) but different by age, education, occupation, type of work force, and perceived exposure to occupational hazards. Support for work-site alcohol testing was highest among blue-collar workers whose jobs involved manufacturing or exposure to work-site hazards.

Accidents, Occupational↗
PubMed1996

Worksite barriers to the effective management of alcohol problems.

The purpose of this analysis is to describe barriers to workplace interventions in cases of alcohol abuse. A survey of 7255 supervisors in 114 worksites across seven major corporations was completed (79% responded). Information about barriers to intervention was elicited by 12 questions. Cluster analysis revealed three analytically independent classes of barriers--Organizational, Interpersonal, and Individual. Most managers reported encountering some barriers to intervention: the extent of barriers perceived was related to characteristics of the worksite, job, and/or the environment. Barriers were greatest for female managers, managers in larger worksites, and the first-line supervisors. Barriers were also related to the form (formal vs informal) of intervention a manager was willing to make. Intervention strategies must take into account differences between company worksites and job levels, and not assume that policies are equally effective throughout the corporation.

Alcoholism↗
PubMed1996

Creatine depletion elicits structural, biochemical, and physiological adaptations in rat costal diaphragm.

To elucidate adaptations elicited by creatine (Cr) depletion in the costal diaphragm (Dia), 16 12-wk-old male Fisher 344 rats had 2% beta-guanidinopropionic acid (beta-GPA), a competitive inhibitor of Cr transport into muscle, added to their food; a control group (Con) of 16 rats ate normal rat chow. After 18 wk, beta-GPA and Con Dia did not differ histochemically with respect to fiber-type distribution; however, the cross-sectional area of type II(b + x) fibers was 33% less in beta-GPA than Con Dia. Biochemically, the proportion of myosin heavy chain IIb in beta-GPA Dia was decreased 42% from Con Dia, whereas the proportions of myosin heavy chains I and IIa were increased. Physiologically, both peak twitch tension and tetanic tension in beta-GPA Dia were decreased 40% from Con. To assess fatigability, we used the protocol of Kelsen and Nochomovitz (J. Appl. Physiol. 53; 440-447, 1982) for 2-6 min duration; the percentage of initial force exhibited by beta-GPA Dia was approximately twice that of Con Dia. We conclude that these structural, biochemical, and physiological adaptations elicited by Cr depletion can all be explained by selective atrophy of IIb muscle fibers in the Dia.

Acclimatization↗
PubMed1996

Work-site variation in managerial drinking.

To assess cross-work-site variation in the general drinking behaviors (on and off the job) of employees, we conducted a cross-sectional survey of managers (n = 7255) at 114 places of work located throughout the continental United States. The work-site mean for the total number of drinks consumed on a typical drinking day ranged from 1.4 to 3.17, a two-fold differential. Regression analysis showed an independent work-site effect, controlling for respondents demographics and type of work. This finding suggests that modifiable work-site characteristics could influence what employees drink on and off the job.

Administrative Personnel↗
PubMed1996

Treatment of chronic tympanic-membrane perforations with a platelet-derived releasate.

PURPOSE: Tympanic membrane perforations are very common and often require surgical treatment. Recent studies have suggested that growth factors may be an effective nonsurgical alternative for treating chronic perforations. The purpose of this study was to assess the efficacy of a platelet releasate in the treatment of chronic nonhealing perforations in the chinchilla model. METHODS: Bilateral perforations were created in 47 chinchillas by excising 80% of the tympanic membrane with a thermal myringotomy knife. Bilateral perforations > 50% of its surface area persisted for 10 weeks in 34 animals, and unilateral perforations > 50% of its surface area, in nine animals. Only animals with bilateral chronic perforations were included in this study. After deepithelializing the perforation and packing the middle ear and external ear canals with Gelfoam, we treated the perforations with either platelet releasate or buffered saline. Each animal served as its own control. RESULTS: The tympanic membranes were evaluated over a 12-week period by microscopy, photography, tympanometry, and histology. No statistical difference between treated and control ears in the incidence of perforation closure was evident. Histologically, the treated tympanic membranes consistently had a thicker fibrous layer than the controls. CONCLUSIONS: These data suggest that platelet releasate is not effective in enhancing closure of chronic tympanic membrane perforations in the chinchilla model.

Animals↗
PubMed1996

Nerve block in prostate surgery.

PURPOSE: We describe a novel technique for anesthetizing the prostate, which should be used for patients at risk undergoing prostate surgery with general, spinal or epidural anesthesia. MATERIALS AND METHODS: Local anesthesia to the prostatic plexus supplemented by monitored anesthesia care was performed on 40 patients with outflow obstruction secondary to an enlarged prostate. Of the patients 34 underwent transurethral resection of the prostate, 5 underwent visual laser ablation and 1 underwent transurethral electrovaporization. A 20 gauge spinal needle was inserted via a suprapubic approach toward the base and apex of the prostate, and guided by the left index finger inserted into the rectum. Lidocaine was injected into the prerectal space. Bulging of the rectal wall caused by the amount of lidocaine injected was appreciated. Insertion into the proper area was essential for a good anesthetic result. RESULTS: Adequate anesthesia levels could be obtained without major complications. All but 1 patient with poor bladder compliance were rendered free of a Foley catheter. There were no deaths. CONCLUSIONS: This technique has definite advantages for patients who are at risk for prostate surgery with general or spinal anesthesia.

Aged↗
PubMed1995

Adrenocorticotropin secretagog release: stimulation by frustration and paradoxically by reward presentation.

Colchicine blockade of axonal transport from the paraventricular nucleus to the median eminence was used to indirectly infer adrenocorticotropin (ACTH) secretagog release in response to a reward presentation and the psychological stressor of frustration. After training rats to drink at the same time of day for 30 min for 2-3 weeks, basal arginine vasopressin (AVP), but not corticotropin-releasing factor (CRF) or oxytocin (OT), concentrations were elevated. The frustration of presenting empty water bottles resulted in increased corticosterone concentrations. Concordantly, CRF, AVP, and OT contents in the median eminence decreased compared to controls. All three secretagogs are thus apparently involved in the corticosterone response to frustration. As expected, water presentation decreased both ACTH and corticosterone. Paradoxically, however, CRF, AVP, and OT contents also decreased compared to controls. The discrepancy of ACTH and corticosterone concentrations declining despite release of secretagogs cannot be explained by decreased adrenal or pituitary sensitivities since both exogenous ACTH and CRF elevated corticosterone and ACTH, respectively, in rewarded rats. Secretagog release, therefore, may not always be associated with stimulation of ACTH release.

Adrenocorticotropic Hormone↗
PubMed1995

Benefit of selective respiratory muscle training on exercise capacity in patients with chronic congestive heart failure.

BACKGROUND: Diminished respiratory muscle strength and endurance have been demonstrated in patients with heart failure. This may contribute to exertional dyspnea and reduced exercise capacity in these patients. The purpose of this study was to investigate whether selective respiratory muscle training could alleviate dyspnea and improve exercise performance in patients with chronic congestive heart failure. METHODS AND RESULTS: Fourteen patients with chronic heart failure (left ventricular ejection fraction, 22 +/- 9%) were enrolled in a supervised respiratory muscle training program. This consisted of three weekly sessions of isocapnic hyperpnea at maximal sustainable ventilatory capacity, resistive breathing, and strength training. Maximum sustainable ventilatory capacity, maximum voluntary ventilation, maximal inspiratory and expiratory pressures, peak VO2, and the 6-minute walk test were measured before (pre) and after (post) 3 months of training. Eight patients completed the training program. Respiratory muscle endurance was improved with training, as evidenced by increases in maximal sustainable ventilatory capacity (pre, 48.6 +/- 10.7 versus post, 76.9 +/- 14.5 L/min; P < .05) and in maximal voluntary ventilation (pre, 100 +/- 36 versus post, 115 +/- 39 L/min; P < .05). Respiratory muscle strength was also increased with training as maximal inspiratory (pre, 64 +/- 31 versus post, 78 +/- 33 cm, H2O; P < .01) and expiratory (pre, 94 +/- 30 versus post, 133 +/- 53 cm H2O; P < .001) pressures rose. Submaximal and maximal exercise capacity were significantly improved with selective respiratory muscle training as the 6-minute walk (pre, 1101 +/- 351 versus post, 1421 +/- 328 ft; P < .001) and peak exercise VO2 (pre, 11.4 +/- 3.3 versus post, 13.3 +/- 2.7 mL.kg-1.min-1; P < .05) both significantly increased. Dyspnea during activities of daily living was subjectively improved in the majority of trained patients. Dyspnea quantified by the Borg scale was significantly reduced during progressive isocapnic hypernea but not during bicycle exercise. No statistically significant improvement in maximal sustainable ventilatory capacity, maximum voluntary ventilation, maximal inspiratory or expiratory mouth pressures, 6-minute walk, or peak VO2 was observed in the 6 patients who did not complete the training program. CONCLUSIONS: Selective respiratory muscle training improves respiratory muscle endurance and strength, with an enhancement of submaximal and maximal exercise capacity in patients with heart failure. Dyspnea during activities of daily living was subjectively improved in the majority of trained patients.

Adult↗
PubMed1995

Social effects and circadian rhythms in squirrel monkey pituitary-adrenal activity.

Simultaneous measures of plasma cortisol and ACTH were collected at the morning peak (AM) and evening nadir (PM) of the circadian rhythm in group-housed and individually housed squirrel monkeys (Saimiri sciureus). Pronounced AM-PM differences in cortisol were evident in both conditions, but morning measures of cortisol in monkeys housed without companions were 32% higher than baseline control values observed when the same monkeys were sampled in groups. Consistent AM-PM differences in cortisol were not associated with consistent AM-PM differences in ACTH, and for monkeys housed without companions, plasma ACTH concentrations were consistently and significantly reduced (23% lower in the morning, 42% lower in the evening). All monkeys were subsequently pretreated overnight when dexamethasone to temporarily suppress the secretion of endogenous ACTH and then challenged the following morning with a bolus injection of synthetic ACTH. Monkeys housed without companions responded to the challenge with greater, more prolonged elevations in cortisol relative to monkeys housed in groups. These observations together suggest that squirrel monkeys housed without companions hypersecrete cortisol at the morning peak of the rhythm because adrenal responsiveness to ACTH is enhanced. Low circulating ACTH levels in turn are maintained by robust glucocorticoid feedback mechanisms that inhibit the synthesis or release of pituitary ACTH.

Adrenocorticotropic Hormone↗
PubMed1995

Activation and inhibition of the hypothalamic-pituitary-adrenal axis of the neonatal rat: effects of maternal deprivation.

These studies investigated the activation and inhibition (negative feedback) of the neonatal rat. The ACTH response of maternally deprived pups is persistently elevated for 30 min, suggesting a deficiency in the negative feedback system. In Experiment 1, we examined the time-course of corticosterone (CORT) and ACTH responses to a saline injection over a 120-min period during development. In deprived pups, CORT and ACTH were persistently elevated throughout the testing period, whereas only 15-day-old nondeprived pups showed ACTH and CORT elevations. Further nondeprived and deprived pups were exposed twice to ether (Experiment 2) or saline injections (Experiment 3) separated by a 1-h interval. Nondeprived pups showed an augmented ACTH response to double exposure to ether, but not to saline. No CORT response to either stimulus was observed. In response to one exposure of each stimulus, deprived pups showed increased ACTH and CORT values and no further elevation to repeated exposure. These results suggest the negative feedback system of neonates is immature, but partially functional in deprived pups. Moreover, nondeprived pups show a stressor-specific response to stress, whereas deprived animals show a similar response to different stimuli.

Adrenocorticotropic Hormone↗
PubMed1995

Patterns of adrenocorticotropin secretagog release in response to social interactions and various degrees of novelty.

Colchicine blockade of axonal transport from the paraventricular nucleus to the median eminence was used to indirectly infer ACTH secretagog release in response to the psychological stressors of social interactions and various degrees of novelty. Placing a rat in a new cage with either the smell or presence of a novel conspecific decreased arginine vasopressin and oxytocin (OT) contents, but not corticotropin-releasing factor content. Secretagog contents were unchanged in rats in their home cages faced with a novel conspecific. Secretagog release during social stress is thus primarily a function of being in a novel setting. For different degrees of novelty, rats were placed in either a novel cage, a novel bucket, or a novel bucket smelling of another rat. Whereas secretagog contents were unchanged with a novel cage, OT content alone decreased in response to both the bucket and the unclean bucket. Despite a graded corticosterone response, there was no distinction in the OT response, suggesting that the colchicine technique cannot accurately reflect gradations of stressors.

Adaptation, Psychological↗
PubMed1995

Evaluating hearing threshold differences between ears as a screen for acoustic neuroma.

Differences in pure tone thresholds between ears were evaluated at two different patient care facilities to determine this measure's value as a screen for acoustic neuroma. We evaluated the audiograms of tumor and nontumor groups to estimate the true positive rates and false positive rates for several decision rules. Threshold differences were found to be a more effective diagnostic tool for females than for males. However, even for the most effective rules, the efficiency of this test alone is mediocre, which indicates that hearing threshold differences between ears must be combined with other criteria for a cost-effective approach to acoustic neuroma identification. Furthermore, tumor size was not predicted by the amount of threshold asymmetry between ears, which suggests that some large, potentially life-threatening tumors may be missed if pure tone threshold differences are the sole criterion for referral for additional tests.

Adult↗
PubMed1995

Electrode ranking of "place pitch" and speech recognition in electrical hearing.

The ability to distinguish electrical stimulation of different electrodes on the basis of "pitch or sharpness" was evaluated with an electrode ranking procedure in 14 individual users of the Nucleus cochlear implant. Prior to the electrode ranking test, absolute thresholds and maximum comfortable loudness levels were measured, and loudness balancing was accomplished across all usable electrodes. Performance on the electrode ranking task was defined in terms of d' per mm of distance between comparison electrodes. Large individual differences were found among cochlear-implant users. In subjects with good to excellent place-pitch sensitivity, the electrode ranking task was limited by a ceiling effect; however, in those with poor to moderate sensitivity d'/mm was relatively constant with spatial separation between electrodes. Place pitch was typically ordered from apical to basal electrodes, i.e., basal electrodes were judged to be higher in pitch than more apical electrodes. However, instances of reversals in place-pitch ordering were seen on some electrodes in some subjects. Instances were also seen of better electrode ranking in the apical half of the electrode array than in the basal half, and vice-versa. Analyses of the electrode ranking functions in terms of d' per stimulus indicated that, in some subjects, perfect performance was reached with as little as 0.75 mm between comparison electrodes, the minimum possible. In other subjects, perfect performance was not reached until the spatial separation between comparison electrodes was over 13 mm, more than three quarters of the entire length of the electrode array. Ten of the subjects also participated in a closed-set recognition task of intervocalic consonants. Although the maximum transmitted information for place of consonant articulation (which is based primarily on spectral speech cues) was only 34%, correlations between place-pitch sensitivity and transmitted speech information were as high as 0.71. This was surprising considering the excellent place-pitch sensitivity exhibited by some of the subjects, and may reflect limitations of the Nucleus speech coding strategy for representing spectrally coded speech information. The two prelingual subjects performed notably poorer on the speech task than the postlingual subjects, even though one of the prelingual subjects demonstrated very good place-pitch sensitivity.

Adult↗
PubMed1995

Growth hormone does not prevent corticosteroid-induced changes in rat diaphragm structure and function.

The present study tested the hypothesis that growth hormone (GH), an anabolic agent, could prevent the abnormalities of diaphragm structure and function associated with short-term administration of the corticosteroid triamcinolone (TR). During a 10-day period, male rats (n = 33) were assigned to control (CTL), TR (1 mg.kg-1.day-1 im), and TR-GH (2 mg.kg-1.day-1 im) groups. Diaphragm weight was significantly reduced in the TR and TR-GH animals compared with the CTL animals, but there was no difference in the diaphragm-to-body weight ratio. Fiber type (I, IIa, and IIx/b) proportions did not differ among the three groups. However, in TR rats there was a significant reduction in the contribution of type IIx/b fibers to total diaphragm cross-sectional area due to marked atrophy (approximately 42% decrease in mean fiber cross-sectional area). There was no significant reversal of TR-induced type IIx/b fiber atrophy by concomitant GH administration. TR and TR-GH groups both exhibited a left-ward shift of the force-frequency relationship and enhanced in vitro fatigue resistance, whereas maximal specific force was unaltered. We conclude that GH does not prevent corticosteroid-induced effects on the diaphragm under these conditions, possibly as a result of reduced nutritional intake associated with TR administration.

Animals↗
PubMed1995

Time for creative integration in medical sociology.

The burgeoning of medical sociology has sometimes been accompanied by unfortunate parochialism and the presence of opposing intellectual camps that ignore and even impugn each other's work. We have lost opportunities to achieve creative discourse and integration of different perspectives, methods, and findings. At this stage we should consider how we can foster creative integration within our field.

Disease↗
PubMed1995

Patient knowledge about electroconvulsive therapy: effect of an informational video.

We wished to ascertain whether the addition of an informational video to the informed consent procedure for electroconvulsive therapy (ECT) results in improved patient knowledge about ECT. Eighteen ECT patients were randomized to consent using the usual written document or using the written document and an informational video. The two groups were similar when compared on demographic variables and scores on the Brief Psychiatric Rating Scale (BPRS) and Mini-Mental State Examination (MMSE). Each subject, just after signing the informed consent document, was administered an 8-question ECT knowledge questionnaire. The addition of an informational video to the consent process for ECT did not result in improved knowledge about ECT. Poor knowledge about ECT might be accounted for by unsuccessful communication from the doctors or cognitive impairment and apathy on the part of the patients. One benefit of the video was increased interest from family members in ECT and the consent process.

Adult↗