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Biomedical subjects

B Lewis

Publications and source records attributed to B Lewis.

At least 37 records · Page 2Linked to original sources
PubMed1998

Comparison of primary and reoperative surgery in patients with Crohns disease.

OBJECTIVE: This study was performed to determine the clinical results of patients with Crohns disease who require surgical resection. The outcome of patients undergoing initial surgery was compared with those having reoperation. METHODS: One hundred sixty-four patients undergoing intestinal resection for Crohns disease at The Mount Sinai Hospital from 1976 to 1989 were studied prospectively. The mean duration of follow-up was 72 months. RESULTS: Ninety patients (55%) underwent initial intestinal resection whereas 74 patients (45%) underwent reoperation for recurrent disease. Patients undergoing reoperation were older (33.4 vs. 38.7 years), had longer durations of disease (8.7 vs. 15.2 years), had shorter resections (60 vs. 46 cm), and were more likely to require ileostomy. Forty-seven percent of the patients with multiple previous resections required an ileostomy. This group also received a mean of 2.3 U blood in the perioperative period and showed a trend to increased symptomatic recurrence (49% vs. 71% at 5 years). CONCLUSIONS: Patients with Crohns disease undergoing first and second reoperation have outcomes similar to those in patients undergoing primary resection. Patients requiring multiple reoperations are more likely to require blood transfusions and permanent ileostomy and to show a greater trend to early symptomatic recurrence.

Adult↗
PubMed1998

Readmissions to drug abuse treatment and HIV risk behavior.

The objectives of the study were (a) to investigate the characteristics of drug abuse treatment clients who return to treatment and (b) among those with readmissions, to describe changes over time in risk behavior for human immunodeficiency virus (HIV) infection and to identify factors associated with behavior change. Data were derived from a multisite HIV surveillance program in a single community; the program used a unique identifier to link HIV test results and behavioral information from multiple contacts. During a 30-month period, 1994 clients were admitted to three satellite facilities of a single treatment agency: detoxification, long-term residential, and outpatient. Of these clients, 574 (29%) had one or more readmissions to the same or a different facility during the 24 months following the index admission. Drug injectors, those tested for HIV, and those living in the community were more likely to be readmitted to treatment. There was little overall change in HIV risk behavior between the index admission and the readmission furthest in time from the index admission. Clients whose index visit was at the residential facility were more likely to reduce their injection risk behavior than those admitted to the other facilities. Clients readmitted to either the residential or the outpatient facility were more likely to have reduced their injection risk behavior than those readmitted to detoxification. Treatment facility was not associated with sexual risk behavior change. Men were more likely than women to reduce their high-risk sexual behaviors. The results underscore the need for treatment programs to make HIV testing readily available to their clients and to make special efforts to assist female clients to reduce their HIV risk.

Adolescent↗
PubMed1998

Formaldehyde in dentistry: a review for the millennium.

This article reviews the history and use of formaldehyde in dentistry. Research from outside the dental field is included, particularly those articles that pertain to mutagenicity and carcinogenicity. The controversies over the use of formocresol continue, despite overwhelming research citing deleterious effects.

Aldehydes↗
PubMed1997

Reactive oxygen species generation by human spermatozoa is induced by exogenous NADPH and inhibited by the flavoprotein inhibitors diphenylene iodonium and quinacrine.

Human spermatozoa possess a specialized capacity to generate reactive oxygen species (ROS) that is thought to be of significance in the redox regulation of sperm capacitation (De Lamirande and Gagnon, 1993; Aitken et al., 1995). However, the mechanisms by which ROS are generated by these cells are not understood. In this study we have examined the possible significance of NADPH as a substrate for ROS production by human spermatozoa. Addition of NADPH to viable populations of motile spermatozoa induced a sudden dose-dependent increase in the rate of superoxide generation via mechanisms that could not be disrupted by inhibitors of the mitochondrial electron transport chain (antimycin A, rotenone, carbonyl cyanide m-chlorophenylhydrazone [CCCP], and sodium azide), diaphorase (dicoumarol) xanthine oxidase (allopurinol), or lactic acid dehydrogenase (sodium oxamate). However, NADPH-induced ROS generation could be stimulated by permeabilization and was negatively correlated with sperm function. Both NADH and NADPH were active electron donors in this system, while NAD+ and NADP+ exhibited little activity. Stereo-specificity was evident in the response in that only the beta-isomer of NADPH supported superoxide production. The involvement of a flavoprotein in the electron transfer process was indicated by the high sensitivity of the oxidase to inhibition by diphenylene iodonium and quinacrine. These results indicate that NAD(P)H can serve as an electron donor for superoxide generation by human spermatozoa and present a simple strategy for the production of motile populations of free radical generating cells with which to study the significance of these molecules in the control of normal and pathological sperm function.

Acridines↗
PubMed1997

The effect of pentoxifylline on random-pattern skin-flap necrosis induced by nicotine treatment in the rat.

Cigarette smoke, and specifically nicotine, has been shown to reduce skin-flap survival. The purpose of this study was to determine if the preoperative administration of pentoxifylline can counteract the deleterious effects of nicotine on skin-flap survival in the rat. Sixty rats were distributed into four groups (n = 15). The survival of modified McFarlane skin flaps was assessed on postoperative day 7. The administration of nicotine (0.6 mg/kg) for 24 weeks preoperatively produced an average skin-flap survival of 59 percent; this was significantly decreased compared with controls (p < 0.05). When similarly treated animals were given pentoxifylline (20 mg/kg) for 30 days preoperatively, the mean skin-flap survival improved significantly to 80 percent (p < 0.05). Withholding nicotine for 2 weeks preoperatively also was found to significantly improve skin-flap survival to 73 percent (p < 0.05). Blood filterability was measured as an indicator of viscosity. The blood filterability in rats that received nicotine for 24 weeks was significantly decreased compared with controls (p < 0.05). Both the addition of pentoxifylline preoperatively and the withholding of nicotine for 2 weeks preoperatively were found to significantly improve blood filterability compared with rats that received nicotine alone for 24 weeks postoperatively (p < 0.05).

Analysis of Variance↗
PubMed1997

Environmental health hazards: the impact on a southern community.

The impact of environment on health is a growing area of concern for nurses. The purpose of this study is to describe and characterize residents living near an abandoned hazardous waste site, assess their past and present exposure risk, and describe health concerns and psychosocial effects. Data were obtained by a door-to-door outreach effort. Networking was also used to identify residents with health concerns. Extensive field notes were taken to record the responses of residents. A preliminary windshield survey was conducted to approximate the number of residents living in the geographic area, assess the residential community, analyze drainage pathways away from the site, and observe outdoor activity patterns. Community concerns from the residential population were collected and analyzed for recurrent themes. Significant off-site activity patterns included use of drainage ditches as play areas for children. Foraging on-site activities included picking berries, crawfishing, geophagy (clay eating), and rabbit hunting. Common health problems described by residents included skin rashes, respiratory-related complaints, reproductive difficulties, and headaches. The majority of residents were concerned about the incidence of cancer in the area. Identifying the concerns of residents and indicators of health problems helps nurses begin to understand the relationship between the environment and health.

Adolescent↗
PubMed1997

The effects of planned duration of residential drug abuse treatment on recovery and HIV risk behavior.

OBJECTIVE: This study assessed the effects of planned duration of residential drug abuse treatment on recovery from drug use and on human immunodeficiency virus (HIV) risk behaviors. METHODS: Two concurrent randomized controlled trials of programs differing in planned duration were conducted: 6-month vs 12-month versions of a traditional therapeutic community program, and 3-month vs 6-month versions of a modified therapeutic community incorporating a relapse prevention and health education program. Outcomes, measured at least 16.5 months after admission, included time from admission to first drug use; severity of drug, alcohol, legal, and employment problems; and risky drug injection and sexual behaviors. RESULTS: Among 539 clients (86% of those enrolled), there were no significant effects of planned duration of treatment upon Addiction Severity Index scores or HIV risk behavior. In the relapse prevention program, clients randomized to the 6-month program had a longer time to first drug use than those in the 3-month program (hazard ratio = 0.74; 95% confidence interval = 0.58, 0.93). Employment problems at follow-up were significantly less severe among clients treated in the therapeutic community than among those in the relapse prevention program. CONCLUSIONS: No overall benefit of extending treatment beyond 6 months was found.

Adult↗
PubMed1996

Dietary fatty acids and progression of coronary artery disease in men.

We examined associations between dietary fatty acids and progression of coronary artery disease (CAD) in 50 men receiving a lipid-lowering diet or usual care in the St Thomas' Atherosclerosis Regression Study. Nutrient intake was assessed by dietary history and computerized food tables. Progression of CAD over 39 mo, measured by a decrease in minimum absolute width of coronary segments (MinAWS) on angiography, was highly correlated with intakes of palmitic, stearic (18:0), palmitoleic, and elaidic (t-18:1) acids (P < 0.001); no protective effects were found with polyunsaturates. Total saturates and trans unsaturates explained 20% of variance in CAD progression. After adjustment for plasma cholesterol and other risk factors, change in MinAWS was most closely associated with intakes of 18:0 and t-18:1 fatty acids (P = 0.009). We suggest that progression of CAD in men is strongly related to intakes of both long-chain saturates and trans unsaturates, the effects of 18:0 and t-18:1 possibly being independent of plasma cholesterol concentration.

Cholesterol↗
PubMed1996

Differences in body composition of black and white girls.

Adults have racial differences in body composition that may modulate risks resulting from obesity. Although black and white children have been shown previously to have differences in bone mineral density and subcutaneous body fat, differences in visceral adipose tissue have not been evaluated. We studied 20 black and 20 white normal-weight girls aged 7-10 y, who were matched for weight, body mass index (BMI), bone age, chronological age, Tanner breast stage, and socioeconomic status. Each underwent anthropometric measurements, bioelectrical impedance analysis, dual-energy X-ray absorptiometry (DXA), and abdominal magnetic resonance imaging (MRI) for determination of total (TAT), visceral (VAT), and subcutaneous (SAT) adipose tissue. Serum lipids and fasting and 2-h oral-glucose-tolerance test (OGTT) glucose and insulin concentrations were also measured. There were no differences between groups in absolute waist circumference or waist-to-hip ratio, but waist-to-thigh ratio was smaller in black than in white girls. Black girls had greater bone mineral density and less TAT, VAT, and SAT than whites. VAT was not significantly correlated with any measure of insulin, or with serum lipids. However, both basal and 2-h OGTT serum insulin were significantly correlated with SAT as assessed by MRI in black girls (r2 = 0.46 for basal insulin, P = 0.001: r2 = 0.31 for 2-h insulin, P = 0.01) but not in white girls (r2 < 0.05, for basal and 2-h insulin, NS). We conclude that there are significant racial differences in body composition and differences in the strength of association between abdominal adipose tissue depots and insulin sensitivity in black and white girls.

Abdomen↗
PubMed1996

An overview of the oral health component of the 1988-1991 National Health and Nutrition Examination Survey (NHANES III-Phase 1).

As part of a Federal consortium, the National Institute of Dental Research's (NIDR) Division of Epidemiology and Oral Disease Prevention (DEODP) staff and consultants collaborated with the National Center for Health Statistics (NCHS) to conduct a national oral health examination as a component of the 1988-94 National Health and Nutrition Examination Survey (NHANES III). The Phase 1 took place between October 18, 1988, and October 24, 1991, at 44 survey locations; Phase 2, between September 20, 1991, and October 15, 1994, at 45 sites. This article provides general background information on the NHANES III and its oral health examination component which pertains to all six years of the full survey. It also focuses on particular aspects of the first three years of the survey (NHANES III-Phase 1)--the database for the articles in this peer-reviewed Special Issue--and provides the essential context for the substantively oriented analyses of the Phase 1 database which are presented in the articles which follow this overview.

Adolescent↗
PubMed1996

Coronary heart disease prevention and the infarctogenic plaque.

The characteristics of a subset of atherosclerotic plaques that is responsible for myocardial infarction (infarctogenic plaques) are increasingly well defined. They include moderate size, a thin fibrous cap, and a large lipid pool. Fissuring of the cap leads to thrombotic occlusion and often to an acute coronary event. Physical stresses on, and proteolytic weakening of, the cap--both related to effects of hyperlipidemia on the plaque--increase the risk of fissuring. Treatment of hyperlipidemia leads to regression of experimental atherosclerosis, promotes regression and reduces progression of human coronary artery disease. The arterial changes in humans are predictive of reduced incidence of coronary events. This sequence of events may reflect gradual depletion of plaque lipids, and also a more rapid depletion of chronic inflammatory cells in the plaque cap that are the source of collagenase and other proteases. The primary objective of lipid-lowering therapy appears to be the induction of these changes in infarctogenic plaques, and vigorous treatment should be targeted on patients likely to harbor such plaques.

Animals↗