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Biomedical subjects

S Levine

Publications and source records attributed to S Levine.

At least 271 records · Page 15Linked to original sources
PubMed1988

Accurate assessment of body composition in obese females.

Although several generalized regression equations exist for body composition assessment the accuracy of these equations for special populations is uncertain. This study examined the ability to predict body composition variables from girth measurements in obese women. Girth measurements were taken on 156 obese women at abdomen 1 and abdomen 2 (mean value of the two was used), buttocks, and right thigh. Stepwise multiple-regression analysis generated on 110 randomly assigned subjects yielded the following equations: density (g/cc) = -0.00020(mean abdomen) - 0.00032(wt) + 0.00039(ht) + 0.97783 (R = 0.76, SEE = +/- 0.00061); % fat = 0.11077(mean abdomen) - 0.17666(ht) + 0.14354(wt) + 51.03301 (R = 0.76, SEE = +/- 2.9); fat wt (kg) = 0.62039(wt) - 0.17844(ht) + 0.09495(mean abdomen) + 5.88874 (R = 0.96, SEE = +/- 2.9); and lean body wt (kg) = 0.37939(wt) + 0.17898(ht) - 0.09494(mean abdomen) - 6.00423 (R = 0.89, SEE = +/- 3.0). Data from the remaining 46 women were used for cross-validation. These equations were valid, with validity coefficients for fat weight and lean body weight of r = 0.92 (SE = +/- 3.3 kg) and r = 0.86 (SE = +/- 3.3 kg), respectively, with no significant mean differences between actual and predicted values. The use of girth measurements is a simple and practical method of estimating fat weight and lean body weight in obese women.

Adult↗
PubMed1988

The response of infants with bronchiolitis to the proteins of respiratory syncytial virus.

Acute phase sera were collected from 28 infants hospitalized with bronchiolitis due to respiratory syncytial (RS) virus and convalescent sera were collected from 24 of them. The sera were assayed for neutralizing antibodies by plaque inhibition, for antibodies to the viral proteins by Western blot against partially purified RS virus, and for their ability to inhibit attachment and fusion. Among the 28 acute phase sera, 27 had antibody to the attachment glycoprotein (G), 16 had antibody to the fusion glycoprotein (F), but none had antibody to the matrix protein (VPM). Both the geometric mean anti-G titre, and the geometric mean anti-F titre correlated with the 50% neutralizing dose (ND50) titre in the acute phase serum. Among the 24 convalescent sera, only four exhibited an increase in neutralizing antibody titre. The response to G appeared to be related to the acute phase ND50 titre. Of 17 infants with acute phase titres of less than 100 ND50/ml, 10 responded to G while there was no response to this protein in seven infants with acute phase titres greater than 100 ND50/ml. While only one infant responded to F, 18 responded to the phosphorylated nucleocapsid protein, VP32, and none responded to VPM. The ability of the acute phase sera to inhibit virus attachment to HeLa cells and to inhibit fusion correlated with the anti-G titre and the anti-F titre, respectively. However, there was no correlation between the inhibition of fusion and the anti-F titre in the convalescent sera, almost all of which inhibited fusion. These results suggest that the infected infants were responding to RS virus, but that their response to the viral proteins was either masked or slowed by residual maternal antibody. The inability to detect VPM in the acute and convalescent phase sera, as well as in 20 paired maternal and cord sera at a 1:50 dilution suggested that VPM, although it is one of the most prevalent viral proteins in both the virion and the infected cell, may be poorly antigenic in humans.

Acute Disease↗
PubMed1988

Low-frequency diaphragmatic fatigue in spontaneously breathing humans.

We used transdiaphragmatic peak twitch tension (PTT) elicited by bilateral phrenic nerve stimulation to ascertain whether low-frequency (LF) diaphragmatic fatigue (DF) can be induced in spontaneously breathing humans by a combination of an inspiratory resistive load (IRL) and graded treadmill exercise (GXT). Our subjects were 10 young males with normal cardiopulmonary function. Before exercise we measured PTT in each subject by administering supramaximal electrical pulses of 100-microseconds duration at a frequency of 1 Hz to each phrenic nerve with the subjects breath holding at functional residual capacity at a given thoracoabdominal configuration. A minimum of six satisfactory PTT measurements were made in each subject, and we computed the 95% confidence limits (CL) for each subject. The subjects then inspired through a resistive load of 38 cmH2O.1(-1).s-1 while carrying out the GXT until exhaustion. After the GXT, PTT was remeasured in all subjects. In five of the subjects, the post-GXT mean PTT fell below the 95% CL of the pre-GXT mean PTT. However, post-GXT PTT means for the other five subjects were within the 95% CL of the pre-GXT means. In conclusion, using PTT as a measure of LFDF, these results demonstrate that LFDF can be produced in 50% of spontaneously breathing young normal males.

Adult↗
PubMed1988

Inspiratory pressure generation: comparison of subjects with COPD and age-matched normals.

We continuously monitored esophageal (Pes) and gastric (Pga) pressures and used these measurements in a three-component model to estimate instantaneous diaphragmatic (DIA), inspiratory accessory muscle (IAM), and postexpiratory recoil (PER) pressures at various times during inspiration. We validated our model both by volume-pressure relationships of the respiratory system (Vrc-Pga and Vab-Pga, where Vrc and Vab are the rib cage and abdominal volumes, respectively) as well as electromyography of the respiratory muscles. Measurements were carried out at rest and during graded treadmill exercise in 11 subjects with chronic obstructive pulmonary disease (COPDs) and 8 age-matched normal subjects (AMNs). AMNs were 59 +/- 2 (SE) yr and had a forced expiratory volume at 1 s (FEV1.0) of 3.6 +/- 0.2 liters; COPDs were 66 +/- 2 yr and had a FEV1.0 of 1.0 +/- 0.1 liters. We noted the following. At rest, both AMNs and COPDs exhibited an increasing DIA pressure (PDIA) across inspiratory time (TI) at rest. As expired minute ventilation increased with exercise intensity, AMNs continued to maintain this PDIA ramp across inspiration; in contrast, COPDs exhibited higher values of PDIA during the first half of TI than during the second half. At all intensities of exercise, COPDs exhibited higher IAM and PER pressures than the AMNs.

Age Factors↗
PubMed1988

Thromboxane A2 in severe hypertension and stroke in stroke-prone spontaneously hypertensive rats.

Thromboxane A2 is a prostanoid having potent platelet aggregatory and vasoconstrictor properties. To determine a possible role for thromboxane A2 in the development of severe hypertension and stroke, we chronically administered the selective thromboxane A2 synthase inhibitor UK-38,485 (Dazmegrel) to stroke-prone spontaneously hypertensive rats (SHRSP). Serum thromboxane B2 (the stable hydrolysis product of thromboxane A2) generation was significantly greater in incubates of whole blood from SHRSP than in those from normotensive control Wistar-Kyoto rats and was inhibited greater than 89% by UK-38,485 administered in vivo. In 10 male SHRSP fed a Japanese-style rat chow and given 1% NaCl in drinking water to accelerate the occurrence of stroke, treatment with 100 mg/kg/day UK-38,485 by gavage starting at 8.6 weeks of age diminished systolic blood pressure elevation at 10 (205 +/- 2 vs. 220 +/- 4 mm Hg, p less than 0.01) and 11 weeks of age (210 +/- 4 vs. 239 +/- 7 mm Hg, p less than 0.01) compared with 10 untreated SHRSP. The ultimate establishment of severe hypertension was not prevented by UK-38,485. Stroke-related mortality was 70% in both UK-38,485-treated and control SHRSP at 14 weeks of age. Histologic examination revealed cerebrovascular lesions consistent with the occurrence of stroke in both control and UK-38,485-treated SHRSP. Our results support a possible role for thromboxane A2 in the elevation of blood pressure in SHRSP but do not support a possible role for the prevention of stroke by thromboxane A2 synthase inhibition in these rats.

Animals↗
PubMed1988

Effect of maternal separation on the complement system and antibody responses in infant primates.

Hemolytic complement activity and complement protein levels were evaluated before and after psychological disturbance in the squirrel monkey. Significant increases in hemolytic complement activity were observed following separation of 6-month-old infants from their mothers. Complement protein levels were generally correlated with hemolytic activity, but did not show the same pattern of change. C3 levels did not change consistently after maternal separation, while C4 decreased significantly on Day 7, and then began to return toward basal levels by Day 14. The alterations in complement activity were associated with elevated adrenal hormone secretion, but were not directly correlated with plasma cortisol levels. A second experiment showed that increased hemolytic complement activity also occurred in juvenile squirrel monkeys following 4-hour to 7-day removals from a peer group. The effect of maternal separation on antibody responses to viral challenge was evaluated in a third experiment. Separated infant squirrel monkeys mounted a smaller antibody response than did control infants that remained with their mothers. A similar decline in antibody responses was observed in separated rhesus macaque infants, but the effect was less marked in this species. Thus, the strong effect of psychological disturbance on immunity in the squirrel monkey is probably related to its prolonged endocrine responses.

Animals↗
PubMed1988

The changing character of the medical profession: a theoretical overview.

Technological advances in medicine have greatly enhanced the ability of physicians to treat disease and disability, but, at the same time, changes in the organization and management of health care services in the United States have imposed constraints on their autonomy. How have these changes--medical advancement and professional decline--affected the theoretical concept of the medical profession? Challenging the prevailing model of professional dominance, the concepts of deprofessionalization, corporatization, and proletarianization emphasize the effects of recent social and economic developments on the changing status of the medical profession. There is evidence, however, that what the proponents of these concepts perceive as the profession's response to external forces are, in fact, the unanticipated consequences of the profession's campaign for autonomy.

Europe↗
PubMed1988

The topography of mercurial lymphadenopathy in brown Norway rats.

Injection of mercuric chloride caused a progressive systemic lymphadenopathy and splenomegaly in Brown Norway (BN) but not in Lewis rats, as reported by others. We studied the number, duration and route of HgCl2 treatments and the topography of the resultant lymphadenopathy, as well as its age and strain dependency. Five injections of HgCl2 increased three-fold the weight of the lymph nodes which became considerably heavier than the spleen. Weanling rats were less susceptible than adults. A regional lymphadenopathy could not be produced. However, a synergistic interaction was observed when the systemic effects of HgCl2 were added to the regional lymphadenopathy produced by injections of metal powders, such that the lymph node mass approached 2% of body weight.

Animals↗
PubMed1988

Retrosternal hemorrhage: an experimental model for study of lymphatic leakage.

Courtice and colleagues observed that blood injected into the peritoneal cavity of rats occasionally leaked from retrosternal lymphatics. The present work shows that this leakage is determined by volume as well as dose of inoculum. The uniform occurrence of visible retrosternal hemorrhage after injection of diluted blood suggests its use as a model for lymphatic leakage. Leakage was prevented when the blood was instilled during the healing phase of a chemical peritonitis.

Animals↗
PubMed1988

Postinflammatory increase of lymphatic absorption from the peritoneal cavity: role of diaphragmatic stomata.

During the healing phase of a chemical peritonitis in rats, absorption of various inocula from the peritoneal cavity into the draining lymph nodes is increased. Heretofore, this phenomenon has been attributed to fibrosis and shrinkage of the greater omentum. The loss of the sequestering function of the omentum allows the inoculum more ready access to the lymphatic vessels in the diaphragm where it is absorbed. In the present work, it is demonstrated that the chemical peritonitis also widens the stomata in the roofs of the diaphragmatic lymphatic lacunes. Both increased access and larger openings contribute to enhanced lymphatic absorption in the postinflammatory state.

Absorption↗
PubMed1988

The frequency of sexual problems among family practice patients.

Two hundred-twelve patients attending a family practice center participated in a questionnaire study of their sexual identity and function. Using conservative definitions of problems, 75% were identified as having at least one specific sexual problem area. Most of these problems were functional in nature and involved desire, arousal, or orgasm. While the frequency of sexual problems was high in both sexes among all age groups, identity problems were primarily seen among the young, and desire problems among older adults. The prevalence rate of reporting sexual problems did not differ significantly by sex. However, females reported more specific sexual problems than males. Only 26% of the subjects summarized their overall sexual lives as problematic and the vast majority of patients thought their family physicians were able to help with such problems. This study reaffirms the high prevalence of sexual disorders in the population. Given adequate training, family physicians may be the ideal providers of assistance for these problems.

Adolescent↗
PubMed1988

Sexual symptoms in hypertensive patients. A clinical trial of antihypertensive medications.

The effects of captopril, methyldopa, and propranolol hydrochloride on reported distress over sexual symptoms over a 24-week treatment period were examined as part of a multicenter, randomized, double-blind clinical trial in which 626 men with mild to moderate hypertension participated. On entry into the clinical trial, 58% of patients taking antihypertensive medications and 44% of men not receiving antihypertensive drugs reported distress over one or more sexual symptoms. Among 304 patients treated with monotherapy who completed the trial, total symptoms distress scores of treatment groups did not differ from each other in change from baseline to week 24, but in particular, problems of maintaining an erection were significantly worsened with propranolol therapy. Among 177 patients treated with monotherapy plus a diuretic, total sexual symptoms distress scores worsened among the groups taking methyldopa or propranolol, with significant worsening in all individual symptoms among patients taking propranolol, and problems in maintaining an erection and in ejaculation among patients receiving methyldopa. Among patients treated with captopril plus a diuretic, no change from baseline appeared in scores for any of the sexual symptoms. The findings underline the importance of taking an adequate sexual history and document that selection of antihypertensive drugs may significantly affect the incidence of sexual symptoms.

Adult↗
PubMed1988

Respiratory muscle rest therapy.

This article discusses the role of respiratory muscle rest therapy in hypercapnic ventilatory failure and/or inspiratory muscle fatigue associated with primary lung disease, diseases of the chest wall, and neuromuscular diseases. Some animal data on the role of ventilatory muscle rest therapy in states characterized by a low cardiac output and arterial hypotension are also reviewed. Additionally, a method for quantitating the degree of respiratory muscle rest elicited by negative pressure ventilation devices is presented.

Cardiac Output, Low↗
PubMed1987

Maternal contact inhibits pituitary-adrenal stress responses in preweanling rats.

Three experiments examined psychological factors which inhibit pituitary-adrenal activity in 12-, 16-, and 20-day-old rats. Infant rats were placed in heated novel test arenas for 30 min--a treatment which increases corticosterone secretion--and were presented with different appetitive stimuli in order to determine whether these stimuli inhibit this increased hormone secretion. The first experiment was a factorial combination of two conditions: suckling an anesthetized dam and milk ingestion through an intraoral cannula. At all ages, suckling inhibited corticosterone secretion but milk ingestion did not, nor was there an interaction of these factors. In the second experiment, the importance of suckling was assessed by allowing pups' contact with an anesthetized dam either with or without the opportunity to suckle. At all ages, contact with suckling and contact alone were equally effective in inhibiting corticosterone secretion. The third experiment asked whether contact with a lactating female is necessary for pituitary-adrenal inhibition or whether more distal cues associated with lactation are sufficient. Pups were tested under one of four treatments formed by a 2(Lactating vs. Virgin Female) X 2(Contact vs. No Contact) factorial design. At all ages inhibition of corticosterone secretion occurred only in animals which were allowed contact with an anesthetized female. Lactating and virgin females were equally effective for the 12- and 16-day-old pups, but contact with a virgin female was less effective for the 20-day-old pups. These findings indicate that neuroendocrine mechanisms subserving inhibition of the pituitary-adrenal system exist during the preweanling period in the rat, and suggest the possibility of maternal regulation of this physiological system during development.

Animals↗
PubMed1987

Influence of postnatal rearing conditions on the response of squirrel monkey infants to brief perturbations in mother-infant relationships.

This study was designed to determine the behavioral and pituitary-adrenal responses of squirrel monkey mother-infant dyads reared under different housing conditions to either 1- or 6-hr separations. Dyads were reared either in an individual cage or in social groups of 3 mother-infant dyads. The two separation conditions consisted of removing either the mother or the infant to a novel test cage while the other member remained in the home cage. Group-reared infants displayed lower levels of plasma cortisol, movement, and vocalization when they remained in the home cage during separation compared to their responses in the novel cage. However, individually-reared infants displayed high cortisol and activity levels in both separation environments, and vocalization levels were higher at 1 hr in the home cage than in the novel cage. These results indicate that familiarity with the separation environment, per se, does not attenuate the behavioral or physiological responses of infants, but that familiar conspecifics, even in the absence of alloparenting, can benefit an infant during separation from its mother. Two additional test conditions assessed the responses of mother-infant dyads when they were only momentarily separated and then immediately reunited in either the home cage or a novel cage. Reunion in the home cage evoked no cortisol or behavioral responses, but reunion in a novel cage resulted in significant elevations in infant cortisol levels and time in contact with the mother. The corticoid response of the mothers differed from their infants during separations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗