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Biomedical subjects

S T Weiss

Publications and source records attributed to S T Weiss.

At least 199 records · Page 11Linked to original sources
PubMed1992

Recovery of leukotriene E4 from the urine of patients with airway obstruction.

The urinary excretion of leukotriene E4 (LTE4) was measured in subjects presenting for emergency treatment of airway obstruction. A total of 72 subjects presenting with airway obstruction performed peak flow determinations before and after three treatments with nebulized albuterol given at 20-min intervals. Of these subjects, 22 more than doubled their peak flow rates, while 19 failed to increase their peak flow rates more than 25% during the treatment period. These groups were designated "responders" and "nonresponders," respectively. Urinary LTE4 excretion was determined in 16 of the 22 responders and 12 of the 19 nonresponders as well as 13 normal subjects by precolumn extraction, analytic reversed-phase high-performance liquid chromatography, and enzyme immunoassay. In the normal subjects the urinary LTE4 excretion was significantly (p less than 0.0001) less than the urinary LTE4 measured in the responder subjects, but not less than the urinary LTE4 excretion in the nonresponder group (p = 0.071). The enhanced recovery of LTE4 from the urine of subjects with acutely reversible airway narrowing is consistent with a bronchoconstrictor role for the cysteinyl leukotrienes in spontaneous acute asthma.

Acute Disease↗
PubMed1992

Perception of airway obstruction in a random population sample. Relationship to airway hyperresponsiveness in the absence of respiratory symptoms.

Subjects with asymptomatic airway hyperresponsiveness in epidemiologic studies may have variable airway obstruction that is not perceived as dyspnea. We tested the hypothesis that such subjects are less likely to report an increase in dyspnea during histamine-induced bronchoconstriction than symptomatic hyperresponders. A random population sample of 412 middle-aged subjects was studied. Before and after a standardized histamine challenge test, subjects recorded Borg scores for dyspnea: any increase in Borg score was considered significant. More than 80% of hyperresponsive subjects (PC10 histamine < or = 16 mg/ml) had no symptoms. The presence of prechallenge dyspnea was related to increased airways responsiveness and current smoking. An increase in Borg score was associated with younger age, more severe airway responsiveness, atopy, and female sex. The level of and increase in the Borg score were not significantly related to level and change in airway caliber (FEV1). In hyperresponsive subjects (PC10 < or = 16 mg/ml), subjects who reported dyspnea, wheeze, or asthma were more likely to show an increase in Borg score during histamine provocation than asymptomatic subjects (adjusted odds ratio 4.01, 95% confidence interval 1.01 to 16.00, p = 0.049), after adjustment for age, sex, smoking habits, FEV1, and atopy. This suggests that asymptomatic hyperresponders may have variable airway obstruction that is not recognized as breathlessness.

Adult↗
PubMed1992

Relationship of skin test reactivity and eosinophilia to level of pulmonary function in a community-based population study.

We studied the relationship of skin test reactivity (sumscore greater than or equal to 3) and eosinophilia (greater than or equal to 275 cells/mm3 blood), separately and combined, to the level of FEV1 in a community cohort. We used the regression analysis technique, adjusting for age and area of residence, and stratifying by gender and cigarette smoking. Eosinophilia, among men, was associated with lower levels of FEV1 in skin test negative subjects with moderate cigarette smoking (greater than or equal to 10 pack-yr: beta = -250 ml, p = 0.02; greater than or equal to 10 pack-yr: beta = -234 ml, p less than 0.01) and in skin test positive subjects who either never smoked (beta = -228 ml, p = 0.06) or had only a brief history of smoking (beta = -428 ml, p less than 0.01). Eosinophilia, among women, was significantly associated with lower levels of FEV1 in never smokers (beta = -95 ml, p less than 0.01), especially if subjects were skin test positive as well (beta = -289 ml, p less than 0.01). Moderate cigarette smoking was uncommon in women. These data suggest an association of indices of inflammation (eosinophilia alone) and allergic inflammation (eosinophilia combined with skin test reactivity) with lower levels of FEV1, independent of the effect of cigarette smoking.

Age Factors↗
PubMed1992

Longitudinal lung function decline in subjects with respiratory symptoms.

The relation of respiratory symptoms and lung function has not been extensively investigated. To determine better the rate of FEV1 decline in subjects reporting persistent wheeze, chronic cough, chronic phlegm, and/or dyspnea, longitudinal data from an adult population sample of 3,948 subjects (1,757 men; 2,191 women) followed for 12 yr were analyzed. At the initial and subsequent follow-up visits, subjects completed a standardized respiratory questionnaire and performed spirometry using the same methods and spirometers. Subjects were categorized based on the presence or absence of self-reported respiratory symptoms (persistent wheeze, chronic cough, chronic phlegm, or shortness of breath) at the initial visit. Six-specific linear regression models were fitted to determine the effect of these respiratory symptoms on lung function. In both men and women, reporting of any respiratory symptoms was associated with both a reduction in initial lung function and more rapid decline in height-adjusted FEV1. Furthermore, after adjustment for height, age, and cigarette smoking, men with cough or phlegm and women with cough alone showed accelerated loss in FEV1. Clinicians should be aware of the predictive value of these respiratory symptoms, because therapeutic intervention may modify the associated decline in lung function.

Cough↗
PubMed1992

Relationship of urinary serotonin excretion to cigarette smoking and respiratory symptoms. The Normative Aging Study.

The relationship of 2-h urinary excretion of serotonin and 5-hydroxyindoleacetic acid (5-HIAA) to cigarette smoking and respiratory symptoms was examined among 631 male participants in the Normative Aging Study (age range, 44 to 85 years). The amount of serotonin excreted in urine was inversely related to age (p less than 0.001). Mean 2-h excretion of serotonin varied from 8.01 micrograms for men 40 to 49 years of age to 5.84 micrograms for those 70 years of age or over. No clear relationship was evident between the amount of 5-HIAA excreted in urine and age. After adjustment for age, current smokers were found to excrete more serotonin (p less than 0.001) and 5-HIAA (p = 0.001) than never smokers. Former smokers did not differ significantly from never smokers in these respects. After adjustment for age and smoking status in a multivariate model, chronic cough was a significant predictor of serotonin excretion (p = 0.005); chronic cough was less predictive of 5-HIAA excretion (p = 0.07). Other respiratory symptoms were unrelated to urinary excretion of serotonin and 5-HIAA. The mechanisms underlying the observed relationships of urinary serotonin and 5-HIAA excretion to smoking and to chronic cough and their potential relevance to chronic bronchitis remain to be determined.

Age Factors↗
PubMed1992

Association of intrauterine cigarette smoke exposure with indices of fetal lung maturation.

The timing of fetal lung maturation is regulated, at least in part, by the fetal endocrine milieu, which in turn may be influenced by environmental factors. Infants of smoking mothers are at decreased risk of neonatal respiratory distress syndrome (RDS), a disease of lung immaturity. Therefore, we measured fetal lung maturity and cigarette smoke exposure to determine whether the lungs of smoke-exposed fetuses mature more quickly and whether changes in maturation are associated with alterations in amniotic fluid (AF) cortisol levels. Amniotic fluid lecithin-sphingomyelin ratio (L/S) and saturated phosphatidylcholine levels were used as measures of lung maturity, while smoke exposure was assessed by measuring AF cotinine, a stable nicotine metabolite. Lung maturity was more advanced in smoke-exposed fetuses as measured by saturated phosphatidylcholine (P = .02) and L/S ratio (P = .04). Smoke-exposed fetuses attained sufficient lung maturity to minimize the risk of RDS approximately 1 week earlier than in unexposed fetuses. The AF of smoke-exposed fetuses also had higher levels of free, conjugated, and total cortisol. Acceleration of lung maturation in smoke-exposed fetuses is consistent with the decreased risk of RDS in infants of smoking mothers. Maternal smoking could influence lung maturation by directly or indirectly enhancing the production and/or secretion of cortisol. Despite the decreased risk of RDS, the developmental process by which smoke-exposed fetuses attain early pulmonary maturity is abnormal and may contribute to the decreased lung function and increased respiratory illness noted in infants of smoking mothers.

Adult↗
PubMed1991

Host and environmental factors influencing the peripheral blood leukocyte count.

The peripheral leukocyte count is an important predictor of mortality. Hence, host and environmental factors influencing the peripheral leukocyte count are of interest. The authors studied 8,635 subjects, aged 30-74 years, who were seen as part of the National Health and Nutrition Examination Survey II in 1976-1980, and sought to assess the relation of age, sex, obesity (body mass index), alcohol use, and various parameters of cigarette smoking to the peripheral leukocyte count using multiple regression analysis. Various parameters of cigarette smoking were statistically significant independent predictors of the peripheral leukocyte count with higher leukocyte counts seen among current smokers, relative to former or never smokers. Among current smokers, a dose-response relation was seen for cigarettes/day and total pack-years smoked. A dose-response relation with pack-years and years since quitting was seen in former smokers. Other variables that were statistically significant independent predictors of a higher peripheral blood leukocyte count were younger age, male sex, increased body mass index, and decreased alcohol consumption. Although the specific cell or cells responsible for these relations are not defined by this analysis, the results support the suggestion that a number of host and environmental factors can influence cellular markers of inflammation.

Adult↗
PubMed1991

Obesity, blood pressure, and the sympathetic nervous system.

Obesity has long been recognized as a major risk factor for the development of hypertension. Recently, insulin level has been shown to correlate with blood pressure in clinical and population-based studies. Since insulin is a major signal in the relationship between dietary intake and sympathetic nervous system activity, the possibility that insulin-mediated sympathetic stimulation is involved in the pathogenesis of hypertension in the obese has been raised. This hypothesis, developed on the basis of studies in laboratory rodents and normal human subjects, is currently being tested in the Normative Aging Study in Boston. Utilizing epidemiologic techniques applied to this defined population, evidence in support of this hypothesis has been accumulated. The preliminary results indicate that in this population, the abdominal form of obesity is associated with higher insulin levels and increased 24-hour urinary norepinephrine excretion (an index of sympathetic activity).

Animals↗
PubMed1991

Cigarette smoking, dietary intake, and physical activity: effects on body fat distribution--the Normative Aging Study.

Studies have indicated that although smokers weigh less than nonsmokers, smokers have greater waist-to-hip circumference ratios after adjustment for age and body mass index (BMI). The purpose of this investigation was to determine whether factors associated with smoking, such as dietary intake, alcohol intake, and physical activity, modified or confounded the relationship between smoking and body fat distribution. The study used cross-sectional data for 765 men aged 43-85 y from the Normative Aging Study. Current smokers were found to have a greater amount of central adiposity, as represented by the abdomen-to-hip circumference ratio (abdomen-hip ratio), than did former smokers and people who never smoked after adjustment for age, BMI, dietary and alcohol intakes, and physical activity. Multiple-linear-regression analysis revealed that physical activity was negatively associated with and alcohol intake was positively associated with the abdomen-hip ratio. These results suggest a direct effect of smoking on body fat distribution, independent of other smoking-related behaviors.

Adipose Tissue↗
PubMed1991

Relation of obesity and diet to sympathetic nervous system activity.

The hypothesis that dietary intake and obesity stimulate the sympathetic nervous system was investigated in a cross-sectional study of 572 men aged 43-85 years from the Normative Aging Study. Habitus was represented by body mass index, as a measure of overall adiposity, and by the ratio of abdomen-to-hip circumference (abdomen/hip ratio), as a measure of centripetal fat distribution. Sympathetic activity was assessed by measurement of 24-hour urinary norepinephrine excretion. Increased body mass index and total caloric intake were independently associated with increased 24-hour urinary norepinephrine excretion (p = 0.0001 and p = 0.0055, respectively). In addition, mean urinary norepinephrine excretion was higher in subjects classified as either hyperglycemic (serum fasting glucose greater than or equal to 113 mg/dl) and hyperinsulinemic (serum fasting insulin greater than or equal to 19 microIU/ml) (p = 0.0023) or in subjects classified as either hyperglycemic or hyperinsulinemic (p = 0.0063) than the mean urinary norepinephrine excretion in normal subjects. These relations were demonstrated to be independent of age, smoking status, and physical activity. Our results are consistent with the hypothesis that insulin mediates sympathetic stimulation in response to dietary intake and increases sympathetic nervous system activity in the obese.

Adipose Tissue↗
PubMed1991

The influence of age and level of pulmonary function on nonspecific airway responsiveness. The Normative Aging Study.

The relationship of age and prechallenge FEV1 to methacholine airway responsiveness was examined among 914 male participants of the Normative Aging Study (age range 41 to 86 yr). Methacholine airway responsiveness was analyzed as both a continuous (dose-response slope) and categorical (PD20 FEV1 greater than 8.6 mumol; PD20 FEV1 less than or equal to 8.6 mumol) variable. Methacholine responsiveness, as assessed by dose-response slope, displayed a significant inverse relationship to the prechallenge level of FEV1 (p less than 0.001). The dose-response slope was directly related to age among former smokers (p = 0.003) but not among current and never smokers. Using a categorical variable rather than the dose-response slope to characterize responder status yielded very similar results. A logistic regression model of the data predicts an approximately threefold greater odds of a positive methacholine challenge test in association with a 500 ml lower FEV1. The model predicts that among former smokers a 20-yr increase in age is associated with an approximately fivefold increase in the odds of a positive methacholine challenge test. This analysis suggests that nonspecific airway responsiveness increases with advancing age among former smokers even after adjustment for prechallenge level of FEV1.

Adult↗
PubMed1991

Is it useful to distinguish between asthma and chronic obstructive pulmonary disease in respiratory epidemiology.

Disagreement exists on how to define asthma in population studies. Features characteristic of asthma also have been demonstrated in nonasthmatic subjects. For example, although in a random sample of 339 subjects investigated in the Netherlands, subjects with a history of asthmatic attacks, wheeze and/or dyspnea, or chronic dry cough on average were the most responsive (mean PD20 values for histamine of 11.5, 17.0, and 15.0 mg/ml) and asymptomatic subjects were the least responsive (mean PD20, 45.4 mg/ml), the distributions of PD20 values in all groups overlapped considerably. The best way to investigate the association between exposure and disease is in a cohort study. It is argued that follow-up studies in patients may have limited meaning because of a high risk for selection bias. Furthermore, in general, diagnostic disease entities will not represent homogeneous exposure groups. It is concluded that end points of disease should be defined as objectively as possible, for instance, as the level of FEV1, or as simple respiratory symptoms such as dyspnea, wheeze, or chronic cough. Terms such as "asthma," "COPD," or "CNSLD" will not be helpful in defining end points because there is a risk that they could introduce bias, misclassification, and hence confusion.

Asthma↗
PubMed1991

Methacholine airway responsiveness and 24-hour urine excretion of sodium and potassium. The Normative Aging Study.

Prior studies have suggested a direct relationship between dietary sodium intake and nonspecific airway responsiveness. The relationship of dietary sodium and potassium intake to methacholine airway responsiveness was examined among 273 male participants of the Normative Aging Study (age range 44 to 82 yr) using 24-h urinary excretion of these cations as a surrogate for intake. Methacholine airway responsiveness was analyzed as dose-response slope, a continuous measure of responsiveness that represents the slope of a line connecting the origin to the last point of the dose-response plot. Greater airway responsiveness to methacholine was associated with greater potassium excretion. A significant relationship between methacholine dose-response slope and potassium excretion (p = 0.014) was observed in multivariate analysis that took into account other covariates, including age, percentage of predicted FEV1, cigarette smoking, and skin test reactivity. In contrast, methacholine airway responsiveness did not appear related to urinary sodium excretion. These data suggest that dietary potassium may have an influence on airway responsiveness of middle-aged and older men.

Adult↗
PubMed1991

Asthma, hay fever, and phlegm production associated with distinct patterns of allergy skin test reactivity, eosinophilia, and serum IgE levels. The Normative Aging Study.

We investigated the relationship of three phenotypic markers of atopy (allergy skin test reactivity, serum IgE level, and eosinophilia) to the prevalence of respiratory symptoms in 1,071 middle-aged and older men participating in the Normative Aging Study. Participants had all been health screened at the onset of the study in the 1960s to exclude individuals with asthma or other chronic respiratory diseases. Respiratory symptoms were grouped into three categories: asthma (adult onset) and other wheezing syndromes; cough and phlegm production; and hay fever. Multivariate logistic regression models were utilized to assess the independent relationship of each phenotypic marker to symptom prevalence adjusted for age, cigarette smoking, and the competing influence of the other markers. In this population, the prevalence of each symptom increased with serum total IgE concentration, this relationship being strongest for asthma. Skin test positivity (greater than or equal to 5 mm induration to one or more aeroallergens) was strongly associated with hay fever but was not significantly associated with symptoms of wheeze or cough and phlegm. Eosinophilia was associated with asthma and with phlegm production. The association of eosinophilia with phlegm production was present in skin test-negative as well as skin test-positive subjects and remained significant even after current smokers and individuals with asthma or hay fever were excluded. These data support the concept that asthma and hay fever are related to different immunologic host factors as reflected by expression of atopy phenotypes. Future investigations of immunologic factors in respiratory disease susceptibility should include, at a minimum, an assessment of all three phenotypic markers of atopy.

Adult↗
PubMed1991

The influence of lower respiratory illness on childhood asthma: defining risk and susceptibility.

This article reviews the role of lower respiratory illness as a risk factor for the development of asthma in childhood. Lower respiratory illness may influence the natural course of lung-function growth and decline directly or indirectly promoting the development of asthma symptoms in susceptible individuals. The authors discuss the current definitions of lower respiratory illness and asthma and the characteristics of the individuals most prone to their effects. Last, they review how socioeconomic status and race affect the lower respiratory illness-asthma relationship.

Asthma↗
PubMed1990

Body fat distribution, blood pressure, and hypertension. A prospective cohort study of men in the normative aging study.

The relation between the abdominal accumulation of body fat, blood pressure, and hypertension was assessed prospectively among 1972 male participants in the Veterans Administration Normative Aging Study. Body mass index (BMI = weight [kg]/height [m]2) and the ratio of abdominal circumference to hip breadth (AC/HB), measured at regular exams, were used as indices of total adiposity and body fat distribution, respectively. Considering blood pressure as a continuous outcome variable (in models that allowed for intraclass correlation), the AC/HB ratio was significantly positively associated with both diastolic and systolic blood pressure (P < 0.001), adjusting for age and BMI. Blood pressure was dichotomized and hypertension risk was assessed using the proportional hazards model, adjusting for age and BMI. Seven hundred cases of hypertension were recorded by study physicians during 35,496 person-years of follow-up. The risk of hypertension increased approximately three-fold (95% confidence interval, 1.7 to 5.2) with a change of one unit in the AC/HB ratio. These estimates were little changed when the effects of smoking and alcohol intake were considered. Thus, the abdominal accumulation of body fat, apart from overall level of adiposity, was associated with both increased blood pressure and an increased risk of hypertension.

Adult↗
PubMed1990

The relationship of eosinophilia and positive skin test reactivity to respiratory symptom prevalence in a community-based population study.

We studied the relationship of the prevalence of a variety of respiratory symptoms to positive skin test reactivity (skin test index greater than or equal to 3) and/or eosinophilia (greater than or equal to 275 eosinophilic cells per cubic millimeter of blood) in a community-based population sample (N = 2805), adjusting for age, gender, area of residence, and cigarette smoking. We considered subjects with neither positive skin test reactivity nor eosinophilia to be the reference group. Positive skin test reactivity without eosinophilia (N = 487; 17.3%) was significantly associated with persistent wheeze (odds ratio value (OR) = 1.6; 95% confidence interval of the odds ratio value (CI) = 1.0 to 2.6) and with asthmatic attacks (OR = 3.2; CI = 2.0 to 5.3). Positive skin test reactivity in combination with eosinophilia (N = 92; 3.3%) was also significantly associated with persistent wheeze (OR = 2.7; CI = 1.2 to 6.0) and with asthmatic attacks (OR = 10.4; CI = 5.3 to 20.2), however, with a stronger association than in subjects with positive skin test reactivity alone. Finally, eosinophilia without positive skin test reactivity (N = 170; 6.1%) was significantly associated with chronic cough (OR = 1.8; CI = 1.2 to 2.7), bronchitis episodes (OR = 2.1; CI = 1.4 to 3.2), dyspnea grade greater than or equal to III (OR = 1.7; CI = 1.0 to 2.8), and asthmatic attacks (OR = 3.0; CI = 1.5 to 6.6).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗