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Biomedical subjects

Ragnar Rylander

Publications and source records attributed to Ragnar Rylander.

28 records · Page 2Linked to original sources
PubMed2003

Endotoxin exposure and lung cancer mortality by type of farming: is there a hidden dose-response relationship?

Previous studies have suggested that those in occupations exposed to endotoxin have a reduced rate of lung/respiratory cancer. An initial investigation found a significantly reduced risk of all sites malignant neoplasms in white male crop and livestock farmers, and black male and female crop farmers. This study provides data on lung/respiratory cancers in the same workers. Data were obtained from occupation and industry-coded US death certificates collected from 26 states for the period 1984-1993. Cause, sex, and race specific proportionate mortality ratios (PMRs) were calculated using a National Institute of Occupational Safety and Health computer program. A pooled relative risk (PRR) was obtained by summing up separately and then dividing the sex-race specific observed and expected cases, separately in crop and livestock farmers. Deaths from respiratory cancer were 12,482 and 2,290, and deaths from lung cancer were 12,091 and 2,201. In each sex and race group respiratory and lung cancer PMRs are generally lower than unity. Lung cancer PRR was 0.80 (0.78-0.81) in crop farmers and 0.70 (0.67-0.73) in livestock farmers, a significant difference (p < 0.0001). Comparison of our findings with those by Nieuwenhuijsen et al. [1999] reporting personal exposure measurements in groups of Californian farmers (endotoxin averaging 132.5 EU/m(3) during livestock farming against 19.9 EU/m(3) during field crop and fruit farming), suggests a decreasing lung cancer risk with increasing endotoxin exposure, and supports a possible dose-response relationship between the two.

Agricultural Workers' Diseases↗
PubMed2002

Low frequency noise enhances cortisol among noise sensitive subjects during work performance.

Salivary free cortisol concentration, rated stress and annoyance were determined in 32 subjects before, during and after carrying out a battery of performance tasks for 2 hours during exposure to ventilation noise, with dominant low frequencies (low frequency noise) or a flat frequency spectrum (reference noise). Both noises had a level of 40 dBA. All subjects were studied on two occasions and were exposed to both noises in strict rotation. Subjects were categorised as high- or low-sensitive to noise in general and low frequency noise in particular on the basis of questionnaires. Cortisol concentrations during the task were not significantly modulated by the noises or related to noise sensitivity alone. The normal circadian decline in cortisol concentration was however significantly attenuated in subjects high-sensitive to noise in general, when they were exposed to the low frequency noise. This noise was rated as more annoying and more disruptive to working capacity than the reference noise. The study showed physiological evidence of increased stress related to noise sensitivity and noise exposure during work. This is the first study to demonstrate an effect of moderate levels of noise on neuroendocrine activity. The impact of long-term exposure to moderate noise levels, and particularly low frequency noise, in the workplace deserves further investigation.

Adult↗
PubMed2002

Effects after inhalation of (1-->3)-beta-D-glucan and relation to mould exposure in the home.

BACKGROUND: Damp conditions indoors favour the growth of microorganisms, and these contain several agents that may cause inflammation when inhaled. Moulds contain a polyglucose in their cell wall, defined as (1-->3)-beta-D-glucan, exhibiting effects on inflammatory cells. AIM: The aim of the present study was to evaluate whether an inhalation challenge to purified (1-->3)-beta-D-glucan (grifolan) in humans could induce effects on inflammatory markers in blood, and to evaluate whether the reactions were related to the home exposure to (1-->3)-beta-D-glucan. METHODS: Seventeen subjects in homes with high levels of airborne (1-->3)-beta-D-glucan (G-high) and 18 subjects in homes with low levels of (1-->3)-beta-D-glucan (G-low) underwent two randomised, double-blind inhalation challenges, one to (1-->3)-beta-D-glucan suspended in saline and one to saline alone. A blood sample was taken before and after the challenges, and differential cell count, granulocyte enzymes in serum and the secretion of cytokines from peripheral blood mononuclear cells (PBMC) were measured. RESULTS: Inhalation challenge with (1-->3)-beta-D-glucan induced a decrease in the secretion of tumour necrosis factor alpha from endotoxin-stimulated PBMC in the G-high group as well as in the G-low group. In the G-high group, the inhalation of (1-->3)-beta-D-glucan induced an increase in blood lymphocytes that was significantly different from the saline-induced effect. CONCLUSIONS: The results suggest that an inhalation challenge to (1-->3)-beta-D-glucan has an effect on inflammatory cells and this effect may be related to a chronic exposure to moulds at home.

Adult↗
PubMed2002

Measurement strategies for the determination of airborne bacterial endotoxin in sewage treatment plants.

Working in sewage plants can involve exposure to different types of microorganisms, viruses and chemicals. The purpose of this study was to evaluate different measurement strategies to determine airborne bacterial endotoxin in such plants. Sewage treatment plants in three municipalities in western Sweden were included. Measurements of airborne endotoxin were performed in April-May and September-October 2001 using personal and stationary samplers. The air sampling times ranged from 60 to 444 min. In stationary and personal sampler measurements, the amounts of airborne endotoxin detected were generally low. At specific worksites, however, higher endotoxin values were identified, with the highest values at worksites located indoors. The results suggest that the exposure situation is relatively stable over a short time period at a specific worksite and that higher values can be recorded during work practices where agitation of wastewater occurs. The results further suggest that airborne endotoxin exposure situations in sewage treatment plants are complex. Sampling techniques, indoor/outdoor measurements and identification of specific worksites/tasks where there is a risk of airborne endotoxin exposure are important factors that must be considered in order to obtain relevant exposure determinations and establish preventive measures from a health risk perspective.

Air Pollutants↗
PubMed2002

Endotoxin in the environment--exposure and effects.

This review deals with endotoxin in the environment and its relation to disease among exposed persons. Data are presented on levels of endotoxin in different environments with maximum values of several microg/m(3). The cellular reactions of importance for inhalation exposure effects are attachment to lipopolysaccharide binding protein, CD14 cell surface protein and TLR-4 receptors. The internalisation of endotoxin in macrophages and endothelial cells results in local production of inflammatory cytokines with subsequent migration of inflammatory cells into the lung and the penetration of cytokines into the blood. These events orchestrate clinical effects in terms of toxic pneumonitis, airways' inflammation and systemic symptoms. Inhalation challenges with pure endotoxin and field studies confirm the relation between these effects and exposure to dusts containing endotoxin. It is possible that polymorphism in genes determining endotoxin reactivity, particularly TLR-4, influences the risk for disease after environmental exposures. Some data suggest that the inflammation caused by inhaled endotoxin may decrease the risk for atopic sensitisation among children and lung cancer among workers exposed to organic dust. Additional research is needed to clarify the role of other environmental agents that are present in connection with endotoxin, particularly (1-->3)-beta-D-glucan from mold cell walls.

Air Pollutants↗
PubMed2002

Diet as risk for lung cancer: a Swedish case-control study.

A case-control study was undertaken to study lung cancer in relation to dietary habits, occupational exposure, and living in urban or country areas. Suspect lung cancer cases in West Sweden and population controls were interviewed using a food frequency questionnaire. The study comprised 177 female and 359 male cases and 916 controls. The cases mainly comprised former and current smokers (82% female, 95% male). For the analysis, cases were divided into the histological diagnoses adenocarcinoma and squamous cell, small cell, and adenosquamous cell carcinomas, as well as into smoking categories. A high frequency of consumption of vegetables was significantly related to a lower risk for adenocarcinoma and squamous cell and adenosquamous cell carcinoma among men and adenocarcinoma among women. A low odds ratio in the highest quartile of vegetable consumption in men was seen in all smoking categories. There were no significant protective effects from fruit in the different lung cancer subgroups, although a significant trend was found for heavy-smoking females. A high consumption of milk was related to an increased risk for lung cancer, especially adenosquamous cell carcinoma. The results suggest that the protective effect or risk due to dietary factors may affect different forms of lung cancer. The results from this as well as previous studies suggest a complex interaction between diet and lung cancer risk, involving the types of lung cancer as well as consumption patterns in the population.

Aged↗
PubMed2002

Second inter-laboratory study comparing endotoxin assay results from cotton dust.

Previously, a large two-part inter-laboratory round robin endotoxin assay study was completed. This first study showed that when cotton dust samples, which are practically identical, are assayed for endotoxin that the intra- laboratory results had a very small variation while intra-laboratory results of the sample had a very high variation. In the first part of the study, each laboratory followed its own in-house assay protocol; but in the second part of the study, when the extraction protocol was standardized, the inter-laboratory results showed a lower variation, which suggested that with further standardization, further reduction of differences between laboratories might be achieved in order that results between laboratories would become more comparable. The results stimulated interest in extending the study to include cotton dust with two levels of endotoxin, standardization of the extraction protocol, and using the same assay kit from the same production lot. The results of this second round robin endotoxin assay study indicate that differences between laboratories are still high, but most of the laboratories could discern the cotton dusts with the different levels of endotoxin.

Chemistry Techniques, Analytical↗
PubMedDate not supplied

Lung function and symptoms among cotton workers and dropouts three years after the start of work.

A longitudinal study of cotton workers was undertaken to assess the presence of work-related medical effects. A cohort of 110 subjects was examined before starting work and one year later. Measurements of pulmonary function were made before and after the work shift. Airway responsiveness was measured using a methacholine challenge test. A questionnaire was used to determine work-related symptoms. The 60 workers who remained after three years experienced an over-shift drop in FEV1 and an increase in airway responsiveness that did not increase after the first year. The data from the dropout group (n = 50) before work and after one year were compared with those for the active workers. The dropout group had a higher prevalence of symptoms of chest tightness and nasal irritation after one year of work. Atopy was not more common in this group. The results suggest that leaving work was related to symptoms of airways inflammation but not to atopy.

Adult↗