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Biomedical subjects

M Weiner

Publications and source records attributed to M Weiner.

At least 19 recordsLinked to original sources
PubMed2000

The survival characteristics of dense sickle cells.

Sickle red blood cells (RBCs) become depleted of potassium, leading to dehydration and abnormally elevated cellular density. The increased sickling that results is important for both hemolysis and vasocclusion. In this study, sickle cells were subjected to high-speed centrifugation, and the bottom 15% were isolated. This procedure removed light cells and to a variable degree enriched cells that were denser than normal to produce a high-density-enriched (HDE) population of sickle cells. Autologous HDE cells from 3 subjects were labeled with biotin and re-infused. The following determinations were performed: (1) the survival and density changes of HDE cells; (2) the amount of fetal hemoglobin (HbF) in labeled cells after magnetic isolation; (3) the percentage of labeled F cells; (4) the percentage of labeled cells displaying external phosphatidylserine (PS). For patients with 3.5%, 4.5%, and 24% HbF in the HDE RBCs, the circulation half-time was 40, 80, and 180 hours, respectively. The percentage of HbF (measured in all 3 subjects) and of F cells (measured in 2 subjects) in labeled RBCs increased with time after re-infusion, indicating that HDE F cells have longer in vivo survival than HDE non-F cells. The percentage of PS(+), biotin-labeled HDE cells showed no consistent increase or decrease with time after re-infusion. These data provide evidence that HDE sickle cells, especially those that do not contain HbF, have a very short in vivo survival, and that the percentage of PS(+) cells in a re-infused HDE population does not change in a consistent manner as these cells age in the circulation.

Anemia, Sickle Cell↗
PubMed2000

An examination of bias in volunteer subject selection: findings from an in-depth child abuse study.

Remarkably few reported studies tested the assumption that a research sample can be constructed which is representative of the population of interest. In order to investigate potential volunteer bias in abuse research, we utilized a database assembled for an NIMH funded study investigating the relationship among adolescent physical abuse, suicidal behavior, and psychopathology. Extensive information was available concerning the nonparticipant pool from which this sample was assembled, allowing for a comprehensive assessment of possible sample bias. The volunteer sample of 99 abused families who agreed to participate in our study was compared on a large number of variables with a random sample of 99 abused families who declined to participate. Comparisons of the two groups did not support the hypothesis that the non-participating families represented a more dysfunctional population. The two groups were far more similar to, than disparate from, each other.

Adolescent↗
PubMed2000

The perception of dyspnoea in patients with asthma, before and following treatment with inhaled glucocorticosteroids.

This study was designed in order to establish the perception of breathlessness during rest and while breathing against resistance, in patients with asthma, before and after 8 weeks of inhaled glucocorticoids (IGC) treatment and to compare these parameters in patients with and without improvement in FEV1. Sixty-seven asthmatic patients, with moderate asthma, attending the asthma clinic, and 20 normal subjects were studied. After a 2-week run-in period, in which the subjects were asked to use exclusively beta2-agonists as needed, the asthmatic patients were randomized to receive either treatment with IGC, 250 microg of fluticasone propionate (FP) twice a day, via a diskhaler (47 patients), or to receive placebo (20 patients) and to serve as a control group, for 8 weeks. Spirometry and measurements for the sensation of dyspnoea were performed before and at the end of the treatment period. The mean dyspnoea score during breathing against resistance was significantly lower (P<0.05) in the patients with asthma than in normal subjects, before entering the study. Following 8 weeks of inhaled FP, there was a significant improvement in the mean dyspnoea score during breathing against resistance in the asthmatics receiving IGCs but not in the control group (P<005). In the study group 32 patients had an improved FEV1 > 15% and 15 patients did not. There was a statistically significant difference in perception of dyspnoea (P<0.01), between the group of patients with a improved FEV1 and the group of patients that were under IGC treatment without improvement in their FEV1. There was also a difference in the mean beta2-agonists consumption between the two groups (P<0.01). Asthmatic patients have a significantly lower perception of dyspnoea compared to normal subjects. IGC treatment was associated with increased perception of dyspnoea. However, this improvement was noted only in patients with improved FEV1, while the patients without improvement remained with an equal degree of dyspnoea perception and beta2-agonists consumption.

Administration, Inhalation↗
PubMed2000

Factors associated with adherence to treatment regimens after lung transplantation.

CONTEXT: The number of patients currently awaiting lung transplantation far exceeds the supply of available organs. Adherence to postoperative treatment regimens is essential for optimal posttransplant success. OBJECTIVE: The present study was designed to examine the demographic and psychological factors associated with compliance in patients who have had lung transplants. DESIGN: Eighteen women and 13 men participated in this study an average of 24 months after transplantation, completing a demographic form, a self-report compliance measure, a social support questionnaire, and the Multidimensional Health Locus of Control Scale. A significant other or family member and the posttransplant nurse coordinator also rated each subject's compliance with the posttransplant regimen. RESULTS: Although patients rated themselves as being compliant with aspects of their self-care, on more subtle measures of compliance, their self-reported compliance was not as impressive. Patients who had had their transplants more recently appeared to be more compliant. Patients with cystic fibrosis used their spirometer more often than patients with other lung diseases. Family support was significantly correlated with self-reported compliance. CONCLUSIONS: This study suggests that how patients are asked about adherence to treatment regimens influences how compliant they appear. The data also indicate that the longer after transplant, the less compliant the patient, and suggests the need for patient reeducation at some point after transplant. Longitudinal studies are needed to assess the degree to which compliance affects the number of rejection and febrile episodes as well as patient mortality after lung transplant.

Adolescent↗
PubMed2000

Specific inspiratory muscle training in patients with mild asthma with high consumption of inhaled beta(2)-agonists.

BACKGROUND: It has been known for many years that there are variations between asthmatic patients in terms of their perception of breathlessness during airway obstruction. STUDY OBJECTIVE: To investigate the relationship between beta(2)-agonist consumption and the score of perception of dyspnea, in mild asthmatics, and the relationship between the effect of specific inspiratory muscle training (SIMT) on the score of perception of dyspnea and beta(2)-agonist consumption in "high perceivers." METHODS: Daily beta(2)-agonist consumption was assessed during a 4-week run-in period in 82 patients with mild asthma. Patients with a mean beta(2)-agonist consumption of > 1 puff/d ("high consumers") then were randomized into two groups: one group of patients received SIMT for 3 months; the other group of patients was assigned as a control group and received sham training. Inspiratory muscle strength and perception of dyspnea were assessed before patients entered the study, following the 4-week run-in period, and after completing the training period. RESULTS: Following the 4-week run-in period, 23 high-consumer patients (mean [+/- SEM] beta(2)-agonist consumption, 2.7 +/- 0.4 puffs/d) were detected. The mean Borg score during breathing against resistance was significantly higher (p < 0.05) in the patients with high beta(2)-agonist consumption than in the subjects with low mean beta(2)-agonist consumption. Following SIMT, the mean maximal inspiratory pressure increased significantly from 94.1 +/- 5.1 to 109.7 +/- 5.2 cm H(2)O (p < 0.005) in the training group. The increase in inspiratory muscle strength was associated with a statistically significant decrease in the mean Borg score during breathing against resistance (p < 0.05) as well as in the mean daily beta(2)-agonist consumption. CONCLUSIONS: We have shown that patients with mild asthma, who have a high beta(2)-agonist consumption, have a higher perception of dyspnea than those with normal consumption. In addition, SIMT was associated with a decrease in perception of dyspnea and a decrease in beta(2)-agonist consumption.

Administration, Inhalation↗
PubMed2000

The cumulative effect of long-acting bronchodilators, exercise, and inspiratory muscle training on the perception of dyspnea in patients with advanced COPD.

BACKGROUND: Dyspnea is a common complaint during daily activities in patients with advanced COPD. The mechanisms underlying dyspnea and the appropriate treatment strategies to relieve it are still not totally understood. We hypothesized that the perception of dyspnea (POD) may be modified by the accumulative effect of bronchodilator therapy, exercise, and inspiratory muscle training (IMT). METHODS: Spirometry, submaximal exercise performance, inspiratory muscle strength and endurance, and the POD were assessed before and following three consecutive 6-week periods of therapy with a long-acting bronchodilator (LABD), the LABD plus exercise, and the LABD plus exercise plus IMT in 30 patients with moderate-to-severe COPD. RESULTS: There was a small, statistically insignificant, increase in FEV(1) in the study group (mean [+/- SEM] increase, 1.42+/-0.3 to 1.49+/-0.4 L) following the LABD therapy period, and no additional increase following the two other periods of therapy. There was a significant increase (p<0.05) in the 6-min walk distance following the therapy period with the LABD plus exercise (mean increase, 252+/-41 to 294+/-47 m) and an additional small increase following the therapy period with the LABD plus exercise plus IMT period (mean increase, 252+/-41 to 302+/-49 m). The decrease in the POD was small and statistically not significant following the therapy periods with the LABD and the LABD plus exercise. The major and statistically significant decrease in the POD was noted following the therapy period with the LABD plus exercise plus IMT. CONCLUSIONS: In patients with moderate-to-severe COPD, following sequential periods of therapy with the LABD, the LABD plus exercise, and the LABD plus exercise plus IMT, there is a cumulative benefit in the POD. The most significant improvement was associated with IMT and not with the LABD and exercise training. The FEV(1) was moderately increased following the therapy period with the LABD, and the addition of exercise has most affected the 6-min walk distance.

Administration, Inhalation↗
PubMed2000

Smoking and first acute myocardial infarction: age, mortality and smoking cessation rate.

BACKGROUND: Cigarette smoking is a major contributor to the risk of acute myocardial infarction and the subsequent morbidity and mortality. Physicians can play an important role in smoking cessation among patients with AMI because of their frequent contact with the patient during the event. OBJECTIVES: To study the prevalence of smoking, age, localization of coronary occlusion, mortality and rate of smoking cessation in consecutive patients who were diagnosed with a first AMI in our center in 1989-93. METHODS: The study included 1,510 consecutive patients with first AMI: 973 men (512 smokers, 52.6%) and 537 women (215 smokers, 40%), whose mean age was 64.1 +/- 6.7 and 68.6 +/- 5.2 years respectively. RESULTS: The median age at the first AMI in non-smoking and smoking men differed significantly (70.4 +/- 6.8 vs. 56.6 +/- 6.1 years, P < 0.001) while the difference in the women was smaller (70.4 +/- 6.9 vs. 66.8 +/- 7.2). The proportion of smokers/non-smokers among men was greater at a younger age and decreased proportionally with age. The overall mortality was 11.3% with a significant difference in mortality rate in the younger age groups between smokers and non-smokers (1% vs. 0% in the age group 31-40 years, P < 0.05, and 6.1% vs. 0.8% in the 41-50 year age group, P < 0.001). Only 62% of the smokers who survived the AMI declared that they had received anti-smoking advice from a physician during hospitalization. The cessation rate in this group was significantly higher than in smokers who had not been cautioned against smoking (56% vs. 18%). CONCLUSIONS: Current smokers sustained their first AMI more than one decade earlier than non-smokers, and the younger smokers had a higher mortality rate. The majority of the smokers who received anti-smoking advice during their hospitalization for AMI quit smoking in the year following the acute event.

Adult↗
PubMed1999

The response to inhaled and oral steroids in patients with stable chronic obstructive pulmonary disease.

BACKGROUND: A significant minority of patients with COPD have favourable response to corticosteroid treatment. In addition, the benefit of corticosteroid treatment may be outweighed by the side-effects. Long-term administration of inhaled steroids is a safe means of treatment. However, only a few studies have addressed the role of inhaled steroids in patients with COPD, with conflicting results. METHODS: Forty-four patients with stable COPD were defined as 'responders to bronchodilators' (increase in FEV1 > or = 20% following administration of beta 2-agonist) (group A), and 124 as 'non-responders to bronchodilators' (group B). All patients were randomized to receive a 6-week course of either a daily dose of 800 micrograms of inhaled budesonide or placebo, separated by 4 weeks when no medication was taken; were randomized again to receive a 6-week course of either 1600 micrograms day-1 of inhaled budesonide, or 800 micrograms day-1 of inhaled budesonide plus placebo; and were randomized once again to receive a 6-week course of either 40 mg day-1 of prednisone or placebo. All stages were performed in a double-blind cross-over design. RESULTS: Following administration of 800 micrograms day-1 of inhaled budesonide, there was an increase in the mean FEV1 from 1.40 +/- 0.20 to 1.92 +/- 0.22 L (P < 0.001) and a significant decrease in inhaled beta 2 agonist consumption in group A. These changes remained almost stable during the increased dose of inhaled budesonide or during prednisone treatment. The mean FEV1 did not change during the placebo period, or in group B in either treatments. CONCLUSIONS: Treatment with inhaled steroids improved spirometry data and inhaled beta 2-agonist consumption in about one-quarter of patients with stable COPD, and this rate increased to about three-quarters in patients who responded to beta 2-agonist inhalation. There was no additional benefit in using a higher dose of inhaled budesonide or prednisone.

Administration, Inhalation↗
PubMed1999

Physically abused adolescents: behavior problems, functional impairment, and comparison of informants' reports.

OBJECTIVE: This study, like earlier studies that focused on younger abused children, ascertained whether physically abused adolescents exhibited increased internalizing and externalizing behaviors. Relevance to pediatric practice is discussed. DESIGN: A cross-sectional design was used to compare the behavior of physically abused adolescents and comparison adolescents using self-reports, parent reports, and teacher reports. The level of agreement among raters was also examined. PARTICIPANTS: The subjects were 99 physically abused adolescents between the ages of 12 and 18 years, who were recruited from Child Protective Services. Comparison subjects were 99 community-recruited nonabused adolescents who were matched for age, gender, and income with the abused adolescents. MEASURES: The behavior of the adolescents was assessed using the Child Behavior Checklist, and the comparable Youth Self-Report and Teacher Report Form, which are widely used measures of behavioral and emotional problems. The Child Global Assessment Scale was also used as a measure of functional impairment and of the need for mental health services. RESULTS: Parents and teachers rated the problems of abused adolescents as significantly greater than the problems of nonabused adolescents on all checklist subscales. Abused adolescents reported significantly greater problems only on externalizing behavior subscales. In addition, based on interviewer ratings, physically abused adolescents exhibited significantly greater functional impairment. CONCLUSIONS: Similar to previous research on abused children, physically abused adolescents exhibit externalizing and internalizing behavior problems and experience greater functional impairment. Parent, teacher, and adolescent reports of externalizing behaviors were similar, but physically abused adolescents reported fewer internalizing behaviors than did the other informants.

Acting Out↗
PubMed1998

Time-dependent changes in the density and hemoglobin F content of biotin-labeled sickle cells.

Sickle red blood cells (RBC) are subject to a number of important cellular changes and selection pressures. In this study, we validated a biotin RBC label by comparison to the standard 51Cr label, and used it to study changes that occur in sickle cells as they age. Sickle RBC had a much shorter lifespan than normal RBC, but the two labels gave equivalent results for each cell type. A variable number of sickle, but not normal, RBC disappeared from the circulation during the first few hours after reinfusion. The number of biotinylated sickle reticulocytes was decreased by 50% after 24 h and 75% after 48 h, with a gradual decrease in the amount of reticulum per cell. The labeled sickle cells exhibited major density increases during the first 4-6 d after reinfusion, with smaller changes thereafter. A small population of very light, labeled sickle RBC was essentially constant in number after the first few days. Fetal hemoglobin (HbF) content was determined in isolated biotinylated sickle RBC after reinfusion, allowing an estimate of lifespan for RBC containing HbF (F cells) and non-F cells. The lifespan of sickle biotinylated RBC lacking HbF was estimated to be approximately 2 wk, whereas F cells survived 6-8 wk.

Anemia, Sickle Cell↗
PubMed1998

Prophylactic inspiratory muscle training in patients undergoing coronary artery bypass graft.

Pulmonary complications after cardiac surgery are a leading cause of postoperative morbidity and mortality. Respiratory muscle weakness may contribute to the postoperative pulmonary abnormalities. We hypothesized that: (1) there is a decrease in inspiratory muscle strength (PImax at residual volume) and endurance (Pmpeak/PImax) following coronary artery bypass graft (CABG); (2) this weakness is associated with reduced pulmonary function tests (PFTs), impaired gas exchange, and a higher rate of pulmonary complications; and (3) prophylactic inspiratory muscle training (IMT) can prevent those changes. Eighty-four candidates for CABG, with ages ranging from 33 to 82 years, were evaluated prior to operation and randomized into two groups: 42 patients underwent IMT using a threshold trainer for 30 min/day for 2 weeks, 1 month before operation (group A); 42 patients served as a control group and underwent sham training (group B). There was a significant decrease in respiratory muscle function, PFTs, and gas exchange in the control group following CABG, whereas these parameters remained similar to those before entering the study in the training group. The differences between the groups were statistically significant. In addition 11 (26%) patients in the control group but only 2 (5%) in the training group needed postsurgical mechanical ventilation longer than 24 hours, CABGs have a significant deteriorating effect on inspiratory muscle function, PFTs, and arterial blood gases. The decrease in these parameters can be prevented by prophylactic inspiratory muscle training, which may also prevent postsurgical pulmonary complications.

Adult↗
PubMed1998

Respiratory muscle training in patients with moderate to severe myasthenia gravis.

BACKGROUND: Myasthenia gravis (MG) is a specific autoimmune disease characterized by weakness and fatigue. MG may affect also the respiratory muscles causing symptoms that may vary from dyspnea on severe exertion to dyspnea at rest. This study was undertaken in order to determine the effects of respiratory muscle training on respiratory muscle performance, spirometry data and the grade of dyspnea in patients with moderate to severe generalized MG. METHODS: Eighteen patients with MG were studied and divided into 2 groups: Group A included 10 patients (3 males and 7 females aged 29-68) with moderate MG, and Group B that included 8 patients (5 males and 3 females aged 21-74) with severe MG. Patients in Group A received both inspiratory and expiratory muscle training for 1/2 h/day, 6 times a week, for 3 months, while patients in Group B followed the same protocol but had inspiratory muscle training only. RESULTS: Mean PImax increased significantly from 56.6 +/- 3.9 to 87.0 +/- 5.8 cm H2O (p < 0.001) in Group A, and from 28.9 +/- 5.9 to 45.5 +/- 6.7 cm H2O (p < 0.005) in Group B. The mean PEmax also increased significantly in patients in Group A, but remained unchanged in the patients in Group B. The respiratory muscle endurance also increased significantly, from 47.9 +/- 4.0 to 72.0 +/- 4.2%, p < 0.001, in patients of Group A, and from 26.0 +/- 2.9 to 43.4 +/- 3.8, p < 0.001, in patients in Group B. The improved respiratory muscle performance was associated with a significant increase in the FEV1 values, and in the FVC values, in patients of both groups. Mean dyspnea index score also increased significantly from 2.6 +/- 0.8 to 3.6 +/- 0.4 (p < 0.005) in Group A, and from 0.7 +/- 0.2 to 2.0 +/- 0.2 (p < 0.001) in Group B. CONCLUSIONS: Specific inspiratory threshold loading training alone, or combined with specific expiratory training, markedly improved respiratory muscle strength and endurance in patients with MG. This improvement in respiratory muscle performance was associated with improved lung function and decreased dyspnea. Respiratory muscle training may prove useful as a complementary therapy with the aim of reducing dyspnea symptoms, delay the breathing crisis and the need for mechanical ventilation in patients with MG.

Adult↗
PubMed1998

Alzheimer's disease under managed care: implications from Medicare utilization and expenditure patterns.

BACKGROUND: Little information is available about the costs, utilization patterns, and the delivery system used by Medicare beneficiaries with chronic illnesses. This information will become increasingly important as more Medicare beneficiaries with chronic illness enroll in managed care plans and delivery systems must be developed to meet their needs. OBJECTIVES: To analyze health care expenditures and utilization patterns for Medicare beneficiaries with dementia of the Alzheimer type (DAT) and compare them with those of all Medicare beneficiaries. DESIGN: A cross-sectional study. SETTING: Practices providing services to Medicare beneficiaries in the U.S. SUBJECTS: Aged Medicare beneficiaries with DAT in fiscal year (FY) 1992. MEASUREMENTS: Medical expenditures and utilization patterns. RESULTS: In FY 1992, per capita Medicare expenditures for 9323 patients with DAT were $6208, or 1.9 times the per capita expenditure for all 1,221,615 beneficiaries in our sample. Inpatient care accounted for 62.7% of expenditures. Internal medicine was the specialty identified with the largest proportion of expenditures, but no single specialty accounted for the majority of care. Payments increased with comorbid conditions such as heart failure, chronic pulmonary diseases, and cerebrovascular disease. CONCLUSION: Current Medicare capitation payments to managed care plans may not meet the higher expected annual costs of care for beneficiaries with DAT. In turn, physicians (or physician groups) who accept capitation for Medicare beneficiaries with DAT should also consider how capitation rates are established by managed care plans and should learn ways to reduce financial risk.

Aged↗
PubMed1998

Influence of excessive weight loss after gastroplasty for morbid obesity on respiratory muscle performance.

BACKGROUND: Morbidly obese subjects are known to have impaired respiratory function and inefficient respiratory muscles. A study was undertaken to investigate the influence of excessive weight loss on pulmonary and respiratory muscle function in morbidly obese individuals who underwent gastroplasty to induce weight loss. METHODS: Twenty one obese individuals with mean (SE) body mass index (BMI) 41.5 (4.5) kg/m2 without overt obstructive airways disease (FEV1/FVC ratio > 80%) were studied before and six months after vertical banded gastroplasty. Only patients who had lost at least 20% of baseline BMI were included in the study. Standard pulmonary function tests and respiratory muscle strength and endurance were measured. RESULTS: Before operation the predominant abnormalities in respiratory function were significant reductions in lung volumes and respiratory muscle endurance and, to a lesser degree, reductions in respiratory muscle strength. All parameters increased towards normal values after weight loss with significant increases in functional residual capacity (FRC) from 84.0 (2.2) to 91.3 (2.5)% of predicted normal values (mean difference 7.3, 95% confidence interval of difference (CI) 4.2 to 10.5), total lung capacity (TLC) from 85.6 (3.0) to 93.5 (3.7)% of predicted normal values (mean difference 7.9, 95% CI 4.5 to 11.5), residual volume (RV) from 86.7 (3.1) to 96.4 (3.0) of predicted normal values (mean difference 9.7, 95% CI 5.2 to 14.1), expiratory reserve volume (ERV) from 76.6 (3.0) to 89.0 (3.4)% of predicted normal values (mean difference 12.4, 95%, CI 6.3 to 18.9), respiratory muscle strength: PImax from 92 (4.4) to 113 (4.6) cm H2O (mean difference 21, 95% CI 12.2 to 31.6), PEmax from 144 (5.6) to 166 (4.3) cm H2O (mean difference 22, 95% CI 12.9 to 32.0), and endurance: PmPeak/PImax from 56 (1.4) to 69 (2.0)% (mean difference 13, 95% CI 9.7 to 16.9). The strongest correlation was between weight loss and the improvement in respiratory muscle endurance. CONCLUSIONS: Lung volumes and respiratory muscle performance are decreased in obese individuals. Weight loss following gastroplasty is associated with improvement in lung volumes and respiratory muscle function.

Adult↗