Biomedical subjects

Y Cormier

Publications and source records attributed to Y Cormier.

150 records · Page 9Linked to original sources

PubMedDate not supplied

Bronchial responsiveness to methacholine in swine confinement building workers.

Bronchial responsiveness to methacholine was measured in 60 swine confinement building workers selected from 461 subjects who participated in a recent epidemiologic survey on the respiratory impact of exposure to this environment. Subjects were divided into the following four groups: group 1, asymptomatic with normal spirometry (n = 16); group 2, asymptomatic with forced expiratory volume in one second/forced vital capacity (FEV1.0/FVC) < 95% predicted (n = 17); group 3, presence of chronic bronchitis with normal respiratory function (n = 13); and group 4, both symptomatic and FEV1.0/FVC < 95% predicted (n = 14). Each subject answered a questionnaire and had a physical examination, PA and lateral chest films, lung volumes and DLCO measurements, and a methacholine bronchoprovocation test. Ages were similar in each group. Physical examination, chest x-rays, and DLCO were normal in all subjects. Values of total lung capacity (TLC) for subjects in group 4 were higher than those of subjects in group 3, and respiratory volume (RV) values of group 4 subjects were higher than those found for all other groups. The provocation dose of methacholine (PC20) was lower for group 4, and the number of subjects with PC20 < 16 mg/ml was greater in this group than in the other groups. We conclude that only swine confinement building workers with both symptoms of chronic bronchitis and abnormal spirometry have an increased bronchial responsiveness to methacholine; however, it is uncertain whether the bronchial responsiveness demonstrated is directly related to the subjects' employment.

Adult↗

PubMedDate not supplied

Assessment of particulates and bioaerosols in eastern Canadian sawmills.

The purpose of this study was to quantify and identify the airborne contamination in eastern Canadian sawmills. Seventeen sawmills were chosen to cover a wide range of size, geographic distribution, and wood species processed. Within each sawmill different work sites (debarking, sawing, sorting, or planing) were studied separately. Area sampling was performed for exposure assessment. Microbial contaminants were assessed with all-glass impingers 30 and six-stage Andersen microbial samplers; appropriate selective media and culture conditions for bacteria, thermophilic actinomycetes, molds, and yeasts were used. Inhalable dust, endotoxins, temperature, and humidity also were measured. Penicillium species were the most predominant molds with up to 40 different Penicillium species identified. Debarking was the working site most highly contaminated by molds, bacteria, and endotoxins (p=0.0001). At this working site mold levels reached a maximum of 1.5 x 10(6) CFU/m3, whereas the median values for culturable bacteria and endotoxin were 21,620 CFU/m3 and 1,081 endotoxin units/m3, respectively. Planing sites were the most highly dust contaminated (median: 3.0 mg/m3) (p <0.05). Sawmills of eastern Canada contain airborne biological contaminants that vary between working sites, and their microflora is different from that previously described in European sawmills.

Air Pollutants, Occupational↗

PubMedDate not supplied

Influence of building maintenance, environmental factors, and seasons on airborne contaminants of swine confinement buildings.

Eight swine confinement buildings, selected to cover the widest possible range of cleanliness, were visited twice during winter and once during summer to verify the range, seasonal variations, and correlations between biological and chemical contaminants. Physical aspects were graded for dirtiness (1 = clean, 10 = dirty), ventilation, air temperature, number of animals, building, and room size. Air samples were taken to measure relative humidity, CO2, ammonia, total dust, and microbiological counts and/or identification (bacteria and molds); endotoxin levels also were measured. During winter, average measurements and ranges were: CO2 = 0.304% (0.254 to 0.349%); ammonia = 19.6 ppm (1.9 to 25.9 ppm); dust = 3.54 mg/m3 (2.15 to 5.60 mg/m3). There were 883 cfu/m3 (547 to 2862 cfu/m3) of molds, 4.25 x 10(5) cfu/m3 (1.67 x 10(5) to 9.30 x 10(5) cfu/m3) of total bacteria, 29 cfu/m3 (3 to 94 cfu/m3) of thermophilic actinomycetes). A significant decrease in bacterial levels (p = 0.04), dust (p = 0.0008), ammonia (p = 0.005), and CO2 (p < 0.0001) was observed during summer sampling when compared with winter levels. Mold counts were positively correlated (p = 0.03) with dirtiness scores, while bacterial counts were negatively correlated with this parameter (p < 0.002), whereas bacteria and endotoxins were correlated with the number of animals (p < 0.05). Ambient gases (CO2 and ammonia) correlated with each other (p = 0.006). Bacteria were the most important contaminant in swine confinement buildings, and endotoxin levels found were also very high (mean = 4.9 x 10(3) EU/m3). We conclude that a wide range of air contamination exists in swine confinement buildings of different maintenance. There is a decrease in some of these contaminants during summer. Observed dirtiness of the swine confinement buildings has a poor predictive value concerning air quality.

Agricultural Workers' Diseases↗

PubMedDate not supplied

[The sleep apnea syndrome. A general review].

During the last years, medical interest has focused on sleep related diseases, especially the sleep apnea syndrome (SAS) and the nocturnal breathing abnormalities associated with broncho-pulmonary diseases. It now appears that SAS is far more prevalent than previously believed. In this review article we present the clinical features, the investigations and the current therapeutic methods. We also discuss the recent developments in our understanding of the SAS pathophysiology and their implications in the disease's management. Clinical importance of sleep related disorders of breathing is appreciated when one looks at some of the secondary effects including hypertension, angina pectoris, cardiac insufficiency and worsening of a broncho-pulmonary disease (hypoxemia, hypercapnia); these are associated with a high degree of morbidity. The recent advent of ambulatory screening systems allows an easier evaluation of patients at risk, such as obese or hypertensive snorers and patients with hypersomnolence; then the diagnostic polysomnographic studies can be reserved for subjects in whom home recording is abnormal. A precise and early diagnosis is important to allow the initiation of treatment such as Continuous Positive Airway Pressure (CPAP) or naso-pharyngeal surgery.

Humans↗

PubMedDate not supplied

Quantification of the effect of gas exchange on the slope of phase III.

It was previously shown that gas exchange could contribute to the rising slope of phase III of the single-breath nitrogen (SB-N2) test. This study was done to quantify this role. We studied eight normal volunteers with a series of SB-N2 derived tests where the RV gas was progressively changed from room air to 90% O2 and 10% N2, by 10% increments in O2 and 10% decreases in N2 concentrations (i.e. room air, 70% N2 30% O2, 60% N2 40% O2, etc.). A similar series of SB-R (single-breath reversed gradients test) derived tests was done. Here the RV contained 100% O2 by previous washout, while the inspired gas was changed by 105 steps from room air to 10% N2 90% O2. We therefore have a situation where dilutional N2 gradients change with the % N2, in either the RV or the inspired gas. However, the alveolar volume loss remains the same for all tests. The mean +/- SD slope of phase III in the SB-N2 series for our eight subjects decreased from 0.87 +/- 0.25 with room air to 0.14 +/- 0.07 with 10% N2 90% O2, while its steepness in the SB-R series decreased from 0.62 +/- 0.23 with the inspired room air to 0.11 +/- 0.06 with the final inspiration being 10% N2 90% O2. From these data, we could calculate that the mean % contribution of gas exchange to the slope of phase III was 10.2%.

Breath Tests↗

PubMedDate not supplied

[Influence of sequential breath-holding on the slope of phase III (author's transl)].

Many factors contribute to the slope of phase III of the single-breath nitrogen test (SB-N2). By its effect of nitrogen concentrations, alveolar oxygen exchange may be responsible for a fraction of this slope. In fact, the slope of phase III is steeper when expiratory time is prolonged. We studied the effect of two sequential breath-holding periods of 20 seconds each with ten healthy young male volunteers, by SB-N2 and a reverse technique (SB-R). We observed a sudden increase (mean 1.27%) in the expired nitrogen concentration after each breath-holding period. Closing volume remained the same in all tests, but the slope of phase IV decreased by 44% in SB-N2A (SB-N2 with breath-holding) and increased by 55% in SB-RA. Expiratory vital capacity was significantly less after breath-holding. These data suggest that gas exchange during expiration is partly responsible for the slope of phase III.

Adult↗