Biomedical subjects

E Seal

Publications and source records attributed to E Seal.

5 recordsLinked to original sources

PubMed1992

Effects of steady-state and variable ozone concentration profiles on pulmonary function.

Measurements of ambient ozone (O2) concentration during daylight hours have shown a spectrum of concentration profiles, from a relatively stable to a variable pattern usually reaching a peak level in the early afternoon. Several recent studies have suggested that in estimating exposure dose (O3 concentration [C] x exposure time [T] x ventilation [V]), O3 concentration needs to be weighted more heavily than either ventilation or duration of exposure in the estimates. In this study we tested the hypothesis that regardless of concentration pattern and exposure rate the same exposure dose of O3 will induce the same spirometric response. We exposed 23 healthy male volunteers (20 to 35 yr of age) for 8 h to air, 0.12 ppm O3 (steady-state), and a triangular exposure pattern (concentration increased steadily from zero to 0.24 ppm over the first 4 h and decreased back to zero by 8 h). During the first 30 min of each hour, subjects exercised for 30 min at minute ventilation (VE) approximately 40 L/min. The order of the exposures was randomized, and the exposures were separated by at least 7 days. The response patterns over the 8-h periods for spirometric variables in both O3 exposures were statistically different from air exposure changes and from each other. For FEV1 the p values were 0.017 between air and steady-state profile, 0.002 between air and triangular profile, and 0.037 between steady-state and triangular profiles. Although in the triangular pattern of exposure the maximal O3 concentration was reached at 4 h, the maximum FEV1 decrement (10.2%) was observed at 6 h of exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

The effect of ozone exposure on the dispersion of inhaled aerosol boluses in healthy human subjects.

Acute exposure of humans to low levels of ozone are known to cause decreases in FVC and increases in SRaw. These alterations in lung function do not, however, elucidate the potential for acute small airway responses. In this study we employed a test of aerosol dispersion to examine the potential effects of ozone on small airways in humans. Twenty-two healthy nonsmoking male volunteers were exposed to 0.4 ppm ozone for 1 h while exercising at 20 L/min/m2 body surface area. Before and immediately after exposure, tests of spirometry (FVC, FEV1, and FEF25-75) and plethysmography (Raw and SRaw) were performed. Subjects also performed an aerosol dispersion test before and after exposure. Each test involved a subject inhaling five to seven breaths of a 300-ml bolus of a 0.5 micron triphenyl phosphate aerosol injected into a 2-L tidal volume. The bolus was injected into the tidal breath at three different depths: at Depth A the bolus was injected after 1.6 L of clean air were inhaled from FRC, at Depth B after 1.2 L, and at Depth C after 1.2 L but with inhalation beginning from RV. The primary measure of bolus dispersion was the expired half-width (HW). Secondary measures were the ratio (expressed as percent) of peak exhaled aerosol concentration to peak inhaled concentration (PR), shift in the median bolus volume between inspiration and expiration (VS), and percent of total aerosol recovered (RC). Changes in pulmonary function after ozone exposure were consistent with previous findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Relationships between lung function and physical characteristics in young adult black and white males and females.

The relationships of lung function to physical characteristics in young adults have not been adequately described for different gender-race groups in the United States. As part of a study of the effects of ozone exposure upon Black and White men and women, we measured lung volumes, expiratory flow rates, and airways resistance on a sample of 314 healthy 18-35 yr old nonsmokers. Regression analysis indicated that lung function was adequately described as a linear function of either height or sitting height in each of the four groups, and that while not always significant, gender and race differences in the height and sitting height coefficients were consistently present with those of males and Whites larger than those of females and Blacks, respectively. Lung volumes were frequently observed to be associated with body mass index as measured by Quetelet Index (weight.height.2). The best fitting gender-race specific multiple regression models including these terms and occasional age terms are presented. Two additional models are presented, one of which simultaneously adjusts for both gender and race, and the other of which adjusts for gender for a given race. Comparison of predicted values from our study to those of other studies suggests that the population samples from this study may be similar to those of other American populations reported upon by others.

Adolescent↗

PubMed1976

Oncornavirus-like protein expression in human prostatic tissue.

A sensitive competition radioimmunoassay using 125 I-labelled p 30 interspecies antigen, antiserum specific to the interspecies antigen of the feline leukaemia virus, and aqueous tissue extracts from prostate was used to examine benign hyperplastic prostates for the presence of protein components able to complete with the interspecies viral antigens. Six of 20 prostatic nodular hyperplastic tissues were competitive in radioimmunoassay with the 125 I-labelled viral antigen for binding sites on the antiviral antibodies. These findings suggest the presence of oncornavirus-like proteins in prostatic nodular hyperplasia. No correlation could be made between the presence of competing protein and histological features of acute or chronic prostatitis and squamous metaplasia.

Antibodies, Viral↗

PubMed1975

Detection of oncornavirus antigenic activity in human urothelial tissues.

Our studies indicate that certain urologic tissues demonstrate evidence of proteins which compete with the interspecies antigens of C-type ribonucleic acid viruses for binding sites of the feline and murine oncornavirus antiglobulins. This fact indicates either the association of viral antigens within these tissues or the presence of a protein so similar to the interspecies antigen that it cross reacts. Studies are now underway to localize reacting antigens within these urologic cells, to correlate the immunologic properties with enzymatic properties known to be specific for oncornaviruses and to assay the activity of patient sera with isolated interspecies antigens. Sera from patients with urologic malignancies will be tested to determine whether the sera can effectively absorb reactivity from tissue extracts or compete with reagent rabbit antisera raised against the interspecies component of the viruses. Should either activity be detected in patient sera, clinical screening will be undertaken to determine if this approach is applicable to early detection of urologic malignancies.

Animals↗