Search PubMed⌕ Search

Biomedical subjects

H Weill

Publications and source records attributed to H Weill.

At least 91 records · Page 5Linked to original sources
PubMed1979

Inhalation challenge and pharmacologic studies of toluene diisocyanate (TDI)-sensitive workers.

Workers with "sensitivity" to toluene diisocyanate (TDI) studied in depth in an attempt to determine mechanisms of bronchial hyperreactivity. Tests included provocative inhalation challenge (PIC) with TDI and methacholine challenge. Blood samples obtained prior to and at various times after PIC were used to measure complement and split products of complement and plasma histamine levels and to determine dose-response slopes of lymphocyte cyclic adenosine monophosphate (cAMP) following stimulation with agonists. TDI-reactive individuals were all reactive to methacholine and responded to PIC with TDI by immediate, delayed, or dual bronchospastic reactions. No change in plasma histamine, total complement levels, or split products of complement were measurable. TDI reactors gave decreased lymphocyte cAMP dose response slopes to stimulation with isoproterenol, prostaglandin E1, and TDI, which suggests that impairment of adrenergic receptors may play an important role in TDI reactivity.

Aerosols↗
PubMed1979

Evaluation of dust exposure in asbestos cement manufacturing operations.

Previous investigations of the health of workers of the asbestos cement industry have demonstrated dose-response relationships for the diffuse radiographic changes of asbestosis and pulmonary function impairment. Studies of the mortality experience of past employees have also identified levels of cumulative exposure above which an excess of respiratory cancer could be detected. These epidemiologic studies were based on particulate concentrations determined by the midget impinger. We attempted to develop information that might lead to conversion of particulate to fiber concentrations in the industry in order that the risk assessment could be related to the current membrane filter methods. Pairs of impinger and membrane filter samples were taken in the various areas of the plant. Personal samples were also taken to determine the current exposure of workers. The ratio of fiber concentration to particle count varied from 0.63 to 2.5. Por correlation (0.18) was obtained at low fiber and particle counts and good correlation (0.91) was demonstrated in dustry areas where asbestos and silica were handled in a dry form. The concentration of fibers in 80% of the personal samples was less than 2 fibers/cc, and 60% were less than 0.5 fibers/cc. The results also show that no one conversion factor can be used for all areas of this type of operation.

Asbestos↗
PubMed1979

Mill effect and dose-response relationships in byssinosis.

Four hundred and eighty-six textile workers in three cotton mills and one wool/synthetic mill were studied for symptoms and functional effects of workroom exposure to dust. Byssinosis was found in 5.7% of 386 cotton workers, with an apparent threshold level of 0.5 mg cotton dust/m3 of air. Mean post-shift functional declines were greater in workers exposed to greater than or equal to 0.2 mg/m3. Workers with byssinosis were unequally distributed, however, with respect to job category and mill; and these variables, rather than current dust exposure levels, accounted for the observed distribution of byssinosis prevalence rates. Variation in biological potency of different samples of cotton dust could be responsible for 'mill effect', the residual variation in response rates by mill after controlling for variation due to dust exposure. A number of other potential influencing variables that are likely to be distributed unequally by mill should also be considered. Mill effect should be assessed in large-scale studies of byssinosis, most of which have analysed biological response rates by combining mill and other variables to examine first-order effects of dust dosage. In such analyses, much of the observed variability may be due to factors other than dust dosage.

Air Pollutants, Occupational↗
PubMed1979

Influence of dose and fiber type on respiratory malignancy risk in asbestos cement manufacturing.

This investigation provides information concerning the risk or respiratory malignancy in relation to duration, degree, and fiber type of exposure to asbestos in a manufacturing cohort of 5,645 with long-term follow-up. Excess mortality for this cause was found in groups with moderate and high cumulative exposure (standard mortality ratios of 290 and 226). Analysis of the influence of components of total exposure dose (duration, average concentration) revealed no detectable excess risk in persons employed for less than 2 years or with low-degree average exposure. Exposure to corcidolite (blue) fiber in addition to the predominantly used chrysotile in pipe making appeared to be associated with higher risk than was exposure to chrysotile alone.

Aged↗
PubMed1978

Physical state of airborne p, p'-diphenylmethane diisocyanate (MDI) and its measurement.

The current exposure standard of 0.02 ppm ceiling for MDI by definition refers to a gaseous species. The standard method, recommended by NIOSH, for measuring MDI in air, is also based on the the assumption that MDI is in the gas phase. Investigations in our Unit indicate that a major portion of airborne MDI, in working environments during spraying operations, is present as an aerosol. In view of this finding, the standard method would underestimate the MDI concentration and describing the airborne MDI concentration in "ppm" or "volume/volume unit" in invalid. A new method for calibration of the continuous reading monitors to measure airborne MDI concentration in mg/m3 unit is described.

Aerosols↗
PubMed1978

Elimination of bagassosis in Louisiana paper manufacturing plant workers.

The prevalence of bagassosis was investigated in a Louisiana paper mill, which in the past had considerable numbers of workers with the disease. Based on negative clinical histories and the low number of positive serological reactions of the workers' serum with Thermoactinomyces sacchari antigen, it was concluded that bagassosis was no longer present. This was thought to be due to a different method of storage of bagasse, which retards microbial decay and reduces airborne organic dust, and to the increased awareness of plant management resulting in greater safety measures.

Dust↗
PubMed1978

A comparison of the Jones and Stead-Wells spirometers.

A comparison was made between the noncounterweighted Jones and Stead-Wells spirometers, and "conversion factors" were determined for the forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC). A cross-sectional study produced a high correlation between the instruments for these two measurements, yielding quadratic and linear regression equations ("conversion factors") for FEV1 and FVC, respectively. Standard deviations of measurements were similar for both spirometers. Results from a longitudinal study agreed with the "conversion factors" predicted from the cross-sectional study; however, significant day-to-day variability was observed by both spirometers. Neither spirometer met all of the technical recommendations proposed by the Committees on Environmental Health and Respiratory Physiology of the American College of Chest Physicians; however, the Stead-Wells water-sealed spirometer complied more often than the Jones waterless spirometer (Pulmonor). In addition, the open-circuit procedure used for the Jones spirometer required more corrdination in the subject than did the closed-circuit procedure employed in this study for the Stead-Wells spirometer; however, with application of the "conversion factors," both instruments, yield comparable data and prove adequate for spirometric studies.

Forced Expiratory Flow Rates↗
PubMed1977

Toluene diisocyanate pulmonary disease: immunopharmacologic and mecholyl challenge studies.

Selected workers exhibiting clinical "sensitivity" to toluene diiosocyanate (TDI) (wheezing, cough, and dyspnea upon entering a TDI-containing area) were studied for : (1) in vitro TDI-induced leukocyte histamine release; (2) determination of cyclic 3',5' adenosine monophosphate (cAMP) levels of lymphocytes exposed to TDI; (3) effect of TDI on the isoproterenol-induced increase of lymphocyte cAMP levels: and (4) acetyl-beta-methylcholine (mecholyl) inhalation challenge. TDI did not induce histamine release from leukocytes of "sensitive" or "nonsensitive" individuals, nor were lymphocyte cAMP levels affected by in vitro TDI exposure, TDI did, however, diminish in vitro stimulation of cAMP by isoproterenol. This effect, seen with cells of "sensitive" and "nonsensitive" individuals, appeared to be dose-dependent; there were no significant differences between the two groups. When challenged with mecholyl, 7 of 10 "sensitive" but only 1 of 10 "nonsensitive" individuals showed a greater than 20% decrease in FEV1. These results suggest that TDI-induced obstructive airways disorders may be associated with altered beta-adrenergic function.

Administration, Intranasal↗
PubMed1977

Respiratory health and dust levels in cottonseed mills.

Four cottonseed mills in the southern United States contained high levels of total and respirable dust. A survey of 172 workers showed low prevalences of byssinosis (2-3%) and chronic bronchitis (4%). Mean baseline (out of dust) lung function values were normal. Mean functional declines over the working shift were present on Monday and absent on Friday, indicating an acute bronchoconstrictor response. Despite limitations in translating measured dust levels into estimates of individual exposures, the overall dose-response relationship seems to differ from that found in the cotton textile industry.

Adult↗
PubMed1977

Longitudinal study of workers employed in the manufacture of toluene-diisocyanate.

Workers at a toluene-diisocyanate manufacturing plant were studied longitudinally to determine the effects of the chemical on their health. Studies included health questionnaire, pulmonary function, environmental monitoring, and immunologic testing. Workers reporting increased lower respiratory symptoms were from the nonsmoker group. Environmental monitoring showed frequent excursions of toluene-diisocyanate concentrations above the threshold limiting value. There was poor correlation between area and personal exposure levels. No exposure-related decline of pulmonary function was demonstrable. Immunologic studies showed development of a positive skin test to a toluene-diisocyanate-human serum albumin conjugate by some persons and an increasing incidence of toluene-diisocyanate-specific IgE antibodies as measured by a radioallergosorbent test. Toluene-diisocyanate did not induce histamine release from leukocytes in vitro but did diminish the in vitro stimulation of cyclic adenosine monophosphate by isoproterenol. Most of the clinically sensitive persons demonstrated adverse bronchial response when challenged by inhalation of toluene-diisocyanate. This response was dose dependent in some persons. When challenged with Mecholyl, clinically sensitive persons showed greater reactivity of airways than nonsensitive persons.

Antibodies↗
PubMed1976

Toluene diisocyanate (TDI) pulmonary disease: immunologic and inhalation challenge studies.

Clinical and serologic effects of TDI exposure were studied in 112 occupationally exposed plant workers. Sera were obtained before and after commencement of TDI production. All subjects were skin-tested with common inhalant allergens and a TDI-HSA conjugate. Total eosinophil counts, immunoglobulin quantitations, and specific antibody assays by PCA, P-K, and radioimmunoassay were performed. Clinically "sensitive" individuals were tested by provocative inhalation challenge with from 0.005 ppm to the threshold limit value of 0.02 ppm TDI. No TDI-induced immunologic changes were noted with the exception of 3 individuals who demonstrated small positive wheal-and-erythema reactions to TDI-HSA but not to HSA alone. Inhalation challenge with TDI vapor produced airways obstruction, as measured by FEF (25-75). These responses were of the immediate, delayed, and dual type, and were provoked in some cases with levels as low as 0.005 ppm TDI.

Airway Obstruction↗
PubMed1976

High prevalence of antinuclear antibodies in sandblasters' silicosis.

Of 39 silicotic sandblasters evaluated in 1972 and 1973, 17 (44 per cent) had positive serum antinuclear antibody reactions. This prevalence is higher than those reported for other pneumonconioses. Comparison of the groups positive and negative for antinuclear antibodies showed that patients positive for antinuclear antibodies were unlikely to have normal ventilatory function and were more likely to have roentgenograms showing large opacities. Both groups had similar proportions showing lobar cavitation or contraction.

Antibodies, Antinuclear↗