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Biomedical subjects

K Schechtman

Publications and source records attributed to K Schechtman.

At least 19 recordsLinked to original sources
PubMed1996

The relationship between physical performance measures and independence in instrumental activities of daily living. The FICSIT Group. Frailty and Injury: Cooperative Studies of Intervention Trials.

OBJECTIVES: Understanding the relationship between physical capacity and functional status is required to design exercise interventions to maintain independent living. This study assessed the importance of physical performance in maintaining independence in Instrumental Activities of Daily Living (IADL). DESIGN: A pre-planned meta-analysis of cross-sectional data from six sites of the Frailty and Injury: Cooperative Studies of Intervention Trials (FICSIT). Linear regression was used to estimate the relationship between physical performance and IADL. PARTICIPANTS: 2190 community-dwelling older subjects. MEASUREMENTS: IADL was the dependent variable; gait velocity, balance function, grip strength and chair rise time were the predictor variables. Age, gender, education, falls self-efficacy, and cognitive status were covariates. RESULTS: Gait velocity, balance function, and grip strength were independently related to IADL deficits, after correcting for covariates. The linear slopes were relatively steep. For gait, a decrease of 0.1 m s-1 was associated with 0.10 (95% Cl: 0.17, 0.04) increase in IADL deficits, which is equivalent to 1 ADL deficit in 10 subjects. The linear slopes for hand grip and balance were similar or steeper. In the sites where chair stand time was measured, an increase of 1 second in the time to rise was associated with a 0.14 (0.04, 0.24) increase in IADL deficits. The relationships found in the meta-analytic analysis were consistent across sites which enrolled subjects with widely varying levels of physical performance. CONCLUSION: Simple measures of physical performance were strongly associated with IADL independence after correcting for many previously identified predictors of functional status. The data from this meta-analysis support testing interventions designed to improve physical performance to determine whether improved performance can maintain or improve independence in IADLs.

Activities of Daily Living↗
PubMed1994

Depressive symptomatology and smoking among persons with diabetes.

The purpose of this study was to determine whether (a) symptoms of depression are more prevalent and severe among diabetic smokers than diabetic nonsmokers, (b) smoking is related to depressive symptomatology among diabetic patients, and (c) there is a positive relationship between number of cigarettes smoked and severity of depressive symptoms. Diabetic non-smokers (n = 103) and diabetic smokers (n = 83) were surveyed regarding symptoms of depression as measured by the Beck Depression Inventory (BDI). Depressive symptomatology was more prevalent and severe among smokers than nonsmokers. Smoking was significantly associated with depressive symptomatology. Among smokers, the number of cigarettes smoked per day was independently associated with cognitive symptoms of depression.

Adult↗
PubMed1993

Monitoring of antiviral therapy with quantitative evaluation of HBeAg: a comparison with HBV DNA testing.

The serological endpoint of response in the treatment of chronic hepatitis B is the loss of hepatitis B virus DNA and HBeAg. Because the quantitative measurement of hepatitis B virus DNA in serum has been shown to be useful for monitoring and predicting response to interferon-alpha therapy, we decided to evaluate whether changes in HBeAg concentration could also be used in this manner. Twenty-nine patients who were initially positive for HBeAg and HBV DNA were serially evaluated for HBeAg concentration with a microparticle-capture enzyme immunoassay. HBeAg levels in serum were calculated by means of comparison with a standard curve of fluorescence rate vs. HBeAg concentration. The results, expressed in milliunits per milliliter, were compared with hepatitis B virus DNA levels determined by means of solution hybridization. The baseline HBeAg concentration proved to be the best independent predictor of response on stepwise Cox regression analysis (p = 0.026). Similar disappearance curves were observed for the two markers, although hepatitis B virus DNA became undetectable at an earlier interval in 13 of 16 cases (81%). In the 16 responders, a decline in HBeAg concentration of more than 90% was observed by wk 12 of therapy (mean +/- S.D., 95% +/- 13%). Nonresponders did not demonstrate such steep declines in HBeAg values by wk 12 (mean +/- S.D., 45% +/- 27%), and levels tended to increase at subsequent time points. We conclude that serial monitoring of HBeAg concentration with a technique that should be readily adaptable to clinical laboratories may be useful in the initial evaluation and monitoring of patients undergoing antiviral therapy.

DNA, Viral↗
PubMed1990

Predictors of employee involvement in a worksite health promotion program.

Although worksite health promotion programs have proliferated, little is known about the population they reach. This study of employees of a large utility company compared whether the same characteristics which predict recruitment also predict extended participation. The study also prospectively assessed how risk factors are related to employees' on-going extended participation. The findings demonstrate that sociodemographic predictors of recruitment are almost mirror images of the predictors of extended participation. Over time employees who are at higher risk for cardiovascular disease participated in on-going sessions less frequently. Data suggest that referral to targeted sessions does not result in higher rates of attendance by employees with a particular risk factor, although there is no evidence of selective avoidance. Organizational influences on participation evident from the beginning are sustained through four sessions. Programs targeting higher risk employees nested within worksite-wide programs may be useful to increase the extended participation of individuals at elevated risk for heart disease.

Adult↗
PubMed1989

Use of injectable cultured human fibroblasts for percutaneous tissue implantation. An experimental study.

Large quantities of cultured human facial dermal fibroblasts were propagated from randomly selected patients to determine their relative suitability as percutaneously injectable living implants. Volumetric and histologic comparisons were made between the following implants that were injected subcutaneously into athymic nude mice: (1) cultured human fibroblasts (HFb); (2) cultured human fibroblasts dispersed in Zyderm II collagen (HFb + Zyd); (3) Zyderm II collagen (Zyd); and (4) Zyplast collagen (Zyp). Both the HFb and HFb + Zyd implants were accepted as primary takes but regressed volumetrically at significantly greater rates than either the Zyd or Zyp implants. Correlative immunohistochemical staining revealed that, by 10 days, 90% of the cells within the HFb implants and 80% within the HFb + Zyd implants were of human origin; however, by 9 weeks, approximately 25% of the cells were of human origin in both types of implants. These results indicated that cultured human fibroblasts can be successfully injected as living grafts; however, the subsequent gradual attrition in the numbers of implanted cells, as noted in this model system, limits the long-term retention of the implants.

Animals↗
PubMed1987

Prognostic significance and beneficial effect of diltiazem on the incidence of early recurrent ischemia after non-Q-wave myocardial infarction: results from the Multicenter Diltiazem Reinfarction Study.

Of 576 patients with non-Q-wave acute myocardial infarction enrolled in the Diltiazem Reinfarction Study, 246 (43%) had 1 or more episodes of angina at rest or with minimal effort during 10.5 days of treatment with either diltiazem (90 mg every 6 hours) or placebo. Reinfarction (12.2% vs 3.6%, p less than 0.0001) or death (6.1% vs 1.5%, p = 0.003) was more likely to occur within 2 weeks of randomization in patients with postinfarction angina than in those without angina. Based on serial electrocardiographic data, 115 of the 246 patients with angina had transient ST-T changes and 131 did not. Comparison of the 14-day event rates in these 2 groups showed that the 115 patients with electrocardiographic evidence of ischemia had a higher frequency of reinfarction (20% vs 5.3%, p less than 0.001), more extensive damage as assessed by peak MB-creatine kinase levels (91 +/- 76 vs 37 +/- 19 IU/liter, p = 0.059 [Wilcoxon rank sum]) and a higher mortality rate (11.3% vs 1.5%, p = 0.001). Angina associated with transient ST-T changes occurred in 70 of the 289 patients in the placebo group but in only 45 of the 287 patients in the diltiazem group--a 28% reduction in cumulative life-table incidence (p = 0.0103 [2-tail, log rank]; 95% confidence interval, 9.3 to 53.8%). It is concluded that patients with early postinfarction angina are at increased risk of reinfarction and death, and angina associated with transient electrocardiographic changes identified a very high risk subset. This subset appeared to have a larger area of viable but jeopardized myocardium and benefited from prophylactic therapy with diltiazem.

Actuarial Analysis↗
PubMed1986

Importance of continued activation of thrombin reflected by fibrinopeptide A to the efficacy of thrombolysis.

Factors responsible for initial success or failure of coronary thrombolysis and persistent recanalization or early reocclusion have not been thoroughly elucidated. Both adequate initial clot lysis and preclusion of rethrombosis are required. Failure may reflect clot lysis followed immediately or somewhat later by rethrombosis. To determine whether differences in the intensity and persistence of the activation of thrombin are determinants of success or failure of recanalization, plasma fibrinopeptide A, a fibrinogen product liberated by thrombin, was serially assayed in 19 patients treated with intravenous streptokinase. In patients exhibiting recanalization (n = 9), plasma fibrinopeptide A decreased after administration of streptokinase but before administration of heparin. In patients without initially apparent recanalization, fibrinopeptide A increased, suggesting ongoing thrombosis, and subsequently decreased promptly after heparin. In patients with initial recanalization followed by overt reocclusion the pattern was different. Despite recanalization, fibrinopeptide A continued to rise markedly. Elevations persisted despite administration of heparin. Thus, inhibition of activation of thrombin is associated with successful recanalization. Conversely, persistent activation of thrombin may be a predisposing factor to both apparent initial failure of recanalization and overt early reocclusion.

Coronary Disease↗
PubMed1986

Flecainide and amiodarone interaction.

Oral amiodarone therapy was given to seven patients already taking oral flecainide regularly. In one additional patient, administration of flecainide was temporarily discontinued when amiodarone therapy was begun, and then resumed. Amiodarone produced a rise in mean dose-adjusted flecainide plasma level (trough plasma level at steady state/daily dose) from 2.3 +/- 0.8 to 3.4 +/- 0.9 (ng/ml)(mg/day) (p less than 0.01). Accordingly, the mean dose of flecainide required to maintain similar plasma levels of the drug was one-third lower during combined treatment than during therapy with flecainide alone. This drug interaction must be accounted for when amiodarone and flecainide are used concomitantly.

Adult↗
PubMed1986

Adrenergically mediated variations in the energy required to defibrillate the heart: observations in closed-chest, nonanesthetized dogs.

The day-to-day variations in epicardial defibrillation threshold (DFT) were examined in closed-chest, unanesthetized dogs. In 11 animals, DFT decreased from 15.8 +/- 2.1 J (mean +/- SE) at the beginning of the study (day 1), to 7.4 +/- 1.7 J on day 2 (p less than .0001). DFT measured daily for 5 consecutive days in seven dogs decreased from 22.1 +/- 3.1 J on day 1 to 9.3 +/- 2.3 J on day 2 (p less than .01) and remained stable from day 2 to day 5. Transcardiac impedance, measured in six dogs, decreased from 112 +/- 6 omega on day 1 to 100 +/- 6 omega on day 2 (p = NS). Propranolol given on day 2 in 14 dogs increased DFT from 12.0 +/- 2.2 to 18.0 +/- 3.1 J (p less than .05). The effects on DFT of sequential administration of isoproterenol and propranolol were examined in 10 dogs. Isoproterenol decreased DFT from 10.0 +/- 1.9 to 5.5 +/- 1.5 J when given before propranolol (p less than .001, n = 10), and from 11.7 +/- 3.0 to 9.7 +/- 3.1 J when given after propranolol (p less than .05, n = 9). Propranolol increased DFT from 10.6 +/- 3.0 to 14.6 +/- 3.9 J when given before isoproterenol (p less than .02, n = 9), and from 10.7 +/- 1.4 to 14.4 +/- 1.5 J when given after isoproterenol (p less than .01, n = 10). These experiments demonstrate a sustained cardiac effect of epicardial defibrillation reflected by a decrease in DFT that is partially reversible by propranolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1985

Beta-adrenergic modulation of direct defibrillation energy in anesthetized dog heart.

Catecholamines facilitate ventricular defibrillation in animals. We examined the effects of beta-adrenergic stimulation and blockade on ventricular defibrillation threshold in anesthetized dogs. Calibrated shocks were delivered between epicardial and superior vena caval electrodes, and defibrillation threshold was measured before and after administration of isoproterenol and propranolol. Eight dogs (group 1) received isoproterenol before propranolol. Nine dogs (group 2) received propranolol before isoproterenol. In group 1, the minimum energy required to defibrillate before isoproterenol was 10.6 +/- 1.7 (SE) J and decreased to 5.9 +/- 1.3 with isoproterenol (P less than 0.001). In group 2, the minimum energy required to defibrillate was 8.3 +/- 2.4 J before propranolol and increased to 10.7 +/- 2.2 after propranolol (P less than 0.001). In group 1, propranolol after isoproterenol increased defibrillation threshold (P less than 0.07), whereas in group 2 isoproterenol after propranolol produced no significant change in defibrillation threshold. Thus beta-stimulation decreased defibrillation threshold significantly in the anesthetized dog heart, an effect that was blocked by propranolol. Conversely, propranolol increased defibrillation threshold, an effect that occurred despite prior beta-stimulation, probably because of the short half-life of isoproterenol.

Animals↗
PubMed1984

Increased congestive heart failure after myocardial infarction of modest extent in patients with diabetes mellitus.

To elucidate the factors involved in the reduced survival rate of diabetic patients after acute myocardial infarction (AMI), we prospectively evaluated 100 patients with well-documented diabetes and 426 control patients. We characterized infarct size and analyzed the incidence and severity of congestive heart failure (CHF) and subsequent death with respect to infarct size. The extent of the index infarct was less in diabetic compared to nondiabetic patients, 16.2 +/- 2.2 CK-gm-eq/m2 compared with 19.2 +/- 0.9 (p less than 0.02). However, CHF was more prevalent in diabetic patients (31.2% of the diabetic patients compared to 15.7%). The difference was most prominent in diabetic patients who had sustained prior infarction (50% compared to 16%), but was evident also in diabetic patients with initial infarction (26% compared to 16%). The mortality rate was greater in diabetic patients (p less than 0.04). When diabetic and nondiabetic patients were stratified with respect to the presence or absence of CHF, survival curves were comparable. The increased incidence of CHF despite a smaller infarct size suggests that additional factors must contribute to myocardial dysfunction and the resultant excess in mortality.

Diabetes Complications↗
PubMed1984

The role of trazodone in the treatment of depressed cardiac patients.

The novel antidepressant trazodone is hypothesized to be less cardiotoxic than the tri-tetracyclic antidepressants. Recently, however, 2 patients with preexisting ventricular irritability showed an increased number of ventricular premature beats and of repetitive forms after starting on trazodone. Data are presented here from four studies on the cardiovascular safety of trazodone. Conclusions are: (1) Trazodone has little effect on cardiac conduction. (2) Trazodone does not worsen supraventricular arrhythmias. (3) Trazodone produces less postural hypotension than most other antidepressants and it tends to lower heart rate. (4) Lower doses of trazodone (100-300 mg) are better tolerated and more effective in major depressives simultaneously debilitated by significant cardiovascular disease. (5) It is possible that the so-called 'trazodone aggravation' of ventricular irritability is a statistical artifact--although further research is needed to verify this conclusion, and in the meantime the drug should be used with caution in such patients.

Aged↗
PubMed1984

The role of concentrated sodium solutions in the resuscitation of patients with severe burns.

Seventy-four severely burned patients were resuscitated with intravenous crystalloid solutions that varied in their average sodium concentration. No colloid solution was used. During the first 24 hours, when requirements were greatest, 21 patients received fluids containing less than 150 mEq sodium/L, nearly all of which was lactated Ringer's solution, while for 31 patients the fluids contained more than 199 mEq sodium/L; the remaining 22 patients were treated with fluids of intermediate sodium content (150 to 199 mEq/L). Detailed, computer-assisted analysis of the data was performed. There were no significant intergroup differences in mean hourly urine output, which was in the targeted range of 0.5 to 1 ml/kg, or in urinary sodium excretion. Both the sodium and water loads administered were significantly larger in patients who died than in survivors (P less than 0.0025). This observation is new. The use of concentrated sodium solutions did not increase the sodium requirement, but water loads were significantly lower in patients who received the most concentrated sodium solutions compared to those resuscitated with the least concentrated sodium solutions (P less than 0.014). The data suggest that minimizing the water loads during resuscitation by increasing the sodium content of the administered fluid might improve the chance for survival of severely burned patients.

Acute Disease↗
PubMed1983

Estrogen and progesterone receptor assays on breast carcinoma from mastectomy specimens.

To determine whether autolytic loss of estrogen (ER) and progesterone (PgR) receptors might affect results of assays performed on primary carcinoma samples taken from fresh mastectomy specimens rather than from biopsy specimens, a group of 71 cases were examined, in which both types of samples were assayed. The comparisons showed a small significant reduction in the proportion of positive ER assay results in mastectomy-primary specimens compared with biopsy specimens, although the frequency of high-binding ER results in the mastectomy-primary specimens was not reduced. The number of positive PgR assays on mastectomy-primary specimens was not reduced in comparison with biopsy specimens. Correlation coefficients for ER values in the paired data were r = 0.836 for biopsy versus mastectomy, and r = 0.795 for primary tumor versus nodal metastasis. For PgR biopsy versus mastectomy r = 0.664, and for PgR primary versus node r = 0.352. The mean quantitative ER and PgR values were significantly higher in axillary lymph nodal metastases than in primary carcinomas, and the higher nodal receptor levels were explained in part by significantly higher tumor cellularity. It is concluded that while loss of ER sufficient to cause a false-negative interpretation may possibly occur in a few cases during the course of mastectomy, as a general rule, significant losses do not occur. The performance of assays on axillary metastases in mastectomy specimens is advantageous because of their high cellularity.

Axilla↗
PubMed1983

Effect of exercise training on the blood pressure and hemodynamic features of hypertensive adolescents.

Twenty-five adolescents (aged 16 +/- 1 years) whose blood pressure (BP) was persistently above the 95th percentile for their age and sex were studied before and after 6 +/- 1 months of exercise training and again 9 +/- 1 months after the cessation of training. Maximal oxygen consumption (VO2) increased significantly with training. There was no change in body weight or sum of skinfolds. Both systolic and diastolic BP decreased significantly with training; however, complete BP normalization was not achieved. When the subjects were retested 9 +/- 1 months after cessation of training, systolic BP and VO2 max had returned to pretraining levels; however, diastolic BP was still below pretraining levels in the subjects who had diastolic hypertension initially. Except in subjects who initially had an elevated cardiac output, no consistent hemodynamic changes were found with training or cessation of training to account for the reductions in BP. The subjects whose resting cardiac outputs were high initially had significantly lower cardiac outputs after training as a result of decreases in both heart rate and stroke volume; however, vascular resistance remained unchanged. Sedentary control subjects with similar BP had no significant change in any of the variables measured over a similar period. These data indicate that moderate endurance exercise training can lower BP in otherwise healthy hypertensive adolescents as an initial therapeutic intervention.

Adolescent↗
PubMed1981

Noninvasive assessment of changes in left ventricular function induced by graded isometric exercise in healthy subjects.

This study was designed to characterize the changes in left ventricular performance induced by graded isometric exercise. Fourteen healthy subjects (12 men and 2 women), aged 19 to 27, performed handgrip isometric exercise at 20, 40, and 60 percent of their maximal voluntary contraction (MVC) with three minutes of rest interval between each contraction. Left ventricular performance was assessed by M-mode echocardiography at rest and during each isometric contraction. Left ventricular end-diastolic and end-systolic dimensions did not change significantly. Heart rate and blood pressure increased significantly during each level of isometric contraction. Left ventricular posterior wall thickness fell from 8.6 +/- .4 (mean +/- SE) to 7.1 +/- .5 (P less than 0.01) and 6.5 +/- .4 mm (P less than 0.001) in response to 40 and 60 percent of MVC, respectively. Left ventricular wall thickness to radius ratio decreased progressively as systolic blood pressure increased which suggests increased wall tension. Fractional shortening remained unchanged during graded isometric exercise. However, mean velocity of circumferential fiber shortening (mVcf) increased from 1.08 +/- 0.4 to 1.24 +/- .05 circ/sec (P less than 0.005) in response to 60 percent of MVC. We conclude that the effect of isometric exercise on left ventricular performance depends, to some extent, on the relative strength of muscle contraction. In healthy subjects, isometric exercise of low intensity (less 40 percent of MVC) does not generally result in depression of left ventricular function. Higher levels of isometric exercise may modestly enhance left ventricular performance despite a sudden increase in blood pressure.

Adult↗