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Biomedical subjects

M D Lebowitz

Publications and source records attributed to M D Lebowitz.

At least 145 records · Page 8Linked to original sources
PubMed1982

Significance of intraindividual changes in maximum expiratory flow volume and peak expiratory flow measurements.

To examine criteria to assess significant changes of measurements derived from the forced expiratory vital capacity (FVC), and to examine changes in the peak expiratory flow (PEF) maneuvers, ten subjects were tested on approximately 30 occasions. Since mini Wright peak flow meters are increasingly used for clinical and research purposes, peak flow intraindividual variability and relations to FVC peak flow were examined, each set of tests consisting of five FVC maneuvers and one peak flow. Measurements on a pneumotachograph included FVC, (FEV1), maximum mid-expiratory flow (MMF or FEF25-75%), and instantaneous maximum expiratory flow after 50 and 75 percent expiration of the FVC. PEF measurements were derived using the mini Wright peak flow meter and the pneumotachograph. The coefficients of variation for the FVC measurements were greatest for maximum expiratory flow measurements and least for the FVC and FEV1. Maximum values from each set of tests reduced the variability. From these values, criteria and estimates were derived to evaluate significant intraindividual change. The PEF measurements were evaluated also to determine intraindividual changes. The coefficients of variation were only 2 percent to 14 percent. The peak flows obtained were shown to correlate well with the PVC peak flow.

Adult↗
PubMed1981

Subjective psychological symptoms in outpatient asthmatic adolescents.

Outpatient adolescent asthmatics were studied using the Asthma Symptom Checklist (ASC) of Kinsman et al. The study showed that outpatient asthmatic adolescents are similar in many respects to older institutionalized asthmatics, except that in the former, psychological symptoms are more diffuse and recognition of respiratory symptoms is less severe. Further studies are needed to determine which psychological symptoms are most important in predicting prognosis in affected asthmatics or the development of "psychosomatic" asthma.

Adolescent↗
PubMed1981

Respiratory symptoms and disease related to alcohol consumption.

It was found that alcohol consumption affected respiratory symptoms and lung function, even when age, smoking habits, and other risk factors were taken into account. The effect of alcohol was most consistently noted among male present heavy drinkers who were also heavy smokers. Smoking is a far more important contributor to respiratory symptoms, but alcohol consumption is a significant risk factor as well.

Adult↗
PubMed1981

The relationship of serum immunoglobulin E to cigarette smoking.

Data from adults enrolled in a general population study in Tucson, Arizona, indicated that smokers have higher serum IgE concentrations than nonsmokers, despite a lower rate of allergy skin test reactivity, at least after 35 yr of age. After 15 yr of age there was a significant decline in serum IgE with age in both allergy skin test positive and skin test negative nonsmokers but no significant age decline was noted in similar groups of smokers. Ex-smokers showed a decline in serum IgE concentrations since quitting cigarettes. Also, the marked increase in geometric mean IgE that was seen in nonsmokers during the spring was not observed in smokers. The data suggested that smoking leads, directly or indirectly, to an increase in serum IgE and that this excess IgE may be qualitatively different from that seen in nonsmokers. Possible mechanisms for the effect are discussed. The observations raised the possibility that some of the adverse health effects of smoking might be immunologically mediated.

Adolescent↗
PubMed1980

Epidemiologic observations on eosinophilia and its relation to respiratory disorders.

The percentage of eosinophils (%EOS), determined from a differential blood smear, was measured in 2,311 subjects enrolled in a general population study in Tucson, Arizona. A subgroup of 290 subjects was tested in more detail during a later evaluation in which absolute eosinophil counts, leukocyte counts, and nasal smears for eosinophils were obtained. In men, but not in women, there was a significant tendency for the %EOS to decrease with age. The highest %EOS was noted during the months of February through May, the time when most plants in this region are in bloom. Blood eosinophils were significantly related to allergy skin test reactivity, circulating IgE concentrations, several respiratory symptoms and disease diagnoses, as well as to reduced ventilatory function. Among subjects younger than 55 yr of age, however, ventilatory function was significantly low, and symptom rates increased only when there was allergy skin test reactivity in addition to eosinophilia. Neither allergy skin test reactivity nor eosinophilia alone was related to ventilatory function in this age group. Among older subjects, blood eosinophilia was associated with definite impairment of ventilatory function, regardless of skin test reactivity and independent of smoking habits. The presence of eosinophilia identified a predominantly female group of elderly nonsmokers with markedly impaired ventilatory function. These subjects appeared to fall into the clinical category of "asthmatic bronchitis".

Adolescent↗
PubMed1979

The timing of the forced vital capacity.

Based on analysis of more than 2,500 forced vital capacity (FVC) maneuvers, we examined 2 aspects of the standards for spirometry recommended by the 1977 Snowbird Workshop concerning the timing of the FVC maneuver. We compared the forced expiratory volume in one sec (FEV1) when timing was initiated by the back extrapolation method with FEV1 when timing was initiated by flow or volume threshold to determine whether the latter offered a reliable equivalent. Although the mean differences appear to be relatively small, because of variability in initiating expiratory effort, neither alternative is likely to offer a uniformly accurate numeric equivalent to backward extrapolation. We also measured the volume expired before the initiation of the timing as a per cent of FVC to determine whether 10 per cent was a reasonable limit to apply for acceptability of a test. Although 2 SD from the mean of 4.35 per cent were well within this limit, it appears that the technician's judgment of acceptability is sufficient in most cases.

Forced Expiratory Volume↗
PubMed1979

Assessment of alpha-1-antitrypsin deficiency heterozygosity as a risk factor in the etiology of emphysema. Physiological comparison of adult normal and heterozygous protease inhibitor phenotype subjects from a random population.

For plethysmographic studies of lung mechanics and measurement of pulmonary diffusing capacity, 62 subjects were drawn from a randomly selected population sample. Data obtained from the 24 subjects of heterozygous phenotype for alpha-1-antitrypsin deficiency (PiMZ) were compared by age group with data from 38 normal (PiM) subjects matched for sex, age, and smoking history. Comparison of mean values by age group for lung volumes, diffusing capacity, lung elastic recoil, maximum expiratory flow, and the occurrence of frequency dependence of dynamic compliance revealed no differences between phenotype groups. There was no evidence of an accelerated effect of aging among PiMZ subjects when compared with normal counterparts nor was there evidence of an increased effect of smoking. From these data it appears that the PiMZ phenotype per se is not a risk factor in the development of emphysema.

Adult↗
PubMed1979

Spirometric testing. Number of tests required and selection of data.

To address the questions of whether three or five maneuvers for forced vital capacity (FVC) should be required for adequate spirometric testing and whether the largest or mean values for FVC and the forced expiratory volume in the first second (FEV1) should be used for analysis, we analyzed spirometric data obtained from approximately 3,000 people for each of three consecutive years. The following four algorithms for selection of data were tested: (1) the average of the best two of five measurements; (2) the average of the best two of the first three; (3) the best of five; and (4) the best of the first three. There were no significant differences between any two algorithms within a given year and no differences between any two years for any algorithm. We conclude that there is little to be gained by requiring more than three maneuvers for FVC or in using values other than the largest FEV1 and FVC.

Adolescent↗
PubMed1978

Closing volume and flow volume abnormalities in alpha(1)-antitrypsin phenotype groups in a community population.

Alpha1-antitrypsin phenotype groups, found in a community population studied in Tucson, were compared by using the maximum expiratory flow volume curve and the single-breath nitrogen test, alone and in combination. Subjects 25 to 54 years of age were used for the comparison, among whom there were 728 Pi M, 29 Pi MZ, and 62 Pi MS phenotypes. None of the flow volume parameters or closing volume parameters was able to differentiate among the phenotype groups; subjects in groups heterozygous for alpha1-antitrypsin did not differ from individuals homozygous for Pi M with regard to any or all flow volume or closing volume parameters.

Adult↗
PubMed1977

Relation of protease inhibitor phenotypes to obstructive lung diseases in a community.

To examine the relative risk for the development of obstructive lung disease in persons heterozygous for alpha1-antitrypsin deficiency, we determined protease inhibitor phenotypes in 2944 subjects in a general community population. Phenotype M was found in 89.5 per cent, MS in 7.1 per cent, and MZ in 3.0 per cent of the population. There were two persons of phenotype Z and six of phenotype SZ. The study also included respiratory questionnaires and spirometry. There were no statistically significant differences in the prevalence of respiratory symptoms and diagnoses or of ventilatory impairment among the three major phenotype groups (M, MS and MZ), nor were there differences in the rates of deterioration of function with age or smoking. Consequently, we do not consider population screening for heterozygous alpha1-antitrypsin deficiency to be worthwhile.

Adolescent↗