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Biomedical subjects

R Rylander

Publications and source records attributed to R Rylander.

At least 73 records · Page 4Linked to original sources
PubMed1994

Bird droppings contain endotoxin and (1-->3)-beta-D-glucan.

Samples of bird droppings were collected and the amount of endotoxin and (1-->3)-beta-D-glucan in these was determined using a specific Limulus assay. All samples contained these agents and calculations on airborne levels demonstrated that doses at risk for inflammation and allergic alveolitis were present. Endotoxin and (1-->3)-beta-D-glucan should be considered in investigations on lung disease induced by bird droppings.

Alveolitis, Extrinsic Allergic↗
PubMed1994

Oxygen metabolites from lavage and interstitial lung cells after inhalation of endotoxin in guinea pigs.

Airborne endotoxins play a role in a variety of occupational diseases such as byssinosis and humidifier's disease and are associated with pulmonary and systemic symptoms. An excess generation of oxygen free radicals (including superoxide anion, O2-) by inflammatory cells has been suggested in endotoxemia. We have studied the release of superoxide from guinea-pig lung lavage and interstitial cells and blood monocytes (BMs) at different times after an acute inhalation exposure to bacterial endotoxin. O2- generation was measured by the O2- dismutase-inhibitable reduction of ferricytochrome c, after stimulation with phorbol-myristate-acetate (PMA) or opsonized zymosan (OZ). After endotoxin exposure, the spontaneous release of O2- remained unchanged for the three cell types. From 4 h after exposure until 48 h afterwards, lung lavage cells produced more O2- after PMA or OZ stimulation than did cells from unexposed guinea pigs. The pattern of O2- generation by interstitial cells followed that of lung lavage macrophages. O2- production remained unchanged in BMs at all times. These results suggest that endotoxin inhalation induced a priming of lavage and interstitial cells, mainly macrophages, associated with an increase in O2- production. As O2- production by BMs remained unchanged, this cell is unlikely to be responsible for the systemic symptoms seen after endotoxin inhalation.

Administration, Inhalation↗
PubMed1994

Organic dusts--from knowledge to prevention.

Vegetable, animal, and microbial aerosols (organic dusts) induce a variety of pulmonary disease and subjective symptoms. This review presents the pathology and clinical symptoms related to organic dust exposure. Most of the symptoms are related to inflammation, which is not unexpected in view of the many inflammatory agents present in organic dusts. Prevention is primarily a matter of dust control, information, and medical surveillance. In the future, specific agents like bacterial endotoxins should be controlled.

Air Pollutants, Occupational↗
PubMed1994

Effects of antioxidants and PAF receptor antagonist in intestinal shock in the rat.

In a model of intestinal ischemia-reperfusion resulting in hypotension, mucosal lesions in the small intestine and mortality, the effects of a combination of superoxide dismutase (SOD) and catalase (cat) or a PAF receptor antagonist were tested. Intestinal ischemia was induced in rats and continued for 60 min. After this, the intestine was reperfused. A PAF receptor antagonist, BN 52021, was given 50 min before ischemia in one group, and SOD + cat was given 10 min before reperfusion in one group. One group received normal saline and one group were controls. Blood pressure, mucosal lesions, plasma volume, and endotoxin in plasma were determined up to 3 hr after reperfusion. Mortality was determined over 4 days. Endogenous endotoxin was not found in any of the groups, but the first types of SOD and cat used were contaminated with endotoxin, resulting in exogenous endotoxemia in animals which received those substances. Later endotoxin-free enzymes were used. Neither SOD + cat nor PAF antagonist had any effect on the hypotension or mucosal lesions. Plasma volume remained at the level of the control group after administration of either regimen. Mortality decreased in the group that received SOD + cat. The effects of SOD + cat indicate that free radicals were released in this model at reperfusion, and the effects of the PAF receptor antagonist indicate that PAF participates in membrane damage, but is an intermediary mechanism in the shock model used. The clearance of infused endotoxin from plasma was less effective in the shocked animals, possibly due to a shock effect on reticuloendothelial system (RES).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Pulmonary inflammation induced by repeated inhalations of beta(1,3)-D-glucan and endotoxin.

In an animal model of hypersensitivity pneumonitis (HP) guinea-pigs were exposed for 5 weeks to an aerosol of bacterial endotoxin, beta(1,3)-D-glucan (curdlan) or a combination. Exposure to endotoxin or curdlan showed only small changes in inflammatory cells in airways or the lung wall, histologically or in terms of enzyme secretion from alveolar macrophages. When the two agents were given together, a histology resembling HP was seen with alveolar infiltrates and early granulomas. Inflammatory cells in airways were increased and enzyme production of macrophages was changed, suggesting an effect of curdlan on the inflammatory regulating capacity of airway macrophages. The results suggest that interference with macrophage function and inflammation are important components in the development of HP.

Acetylglucosaminidase↗
PubMed1993

Genetic polymorphism of cytochrome P4502E1 in a Swedish population. Relationship to incidence of lung cancer.

Genetic polymorphism of CYP2E1 was investigated among 195 Swedish patients with lung cancer and 206 controls. Three different polymorphic sites were found, all in introns, using RFLP and the restriction enzymes DraI, RsaI and TaqI. The frequencies of the rare alleles were 0.08-0.18 and much lower than previously described among Japanese. No significant difference in distribution of the polymorphic alleles between controls and lung cancer patients was evident, in contrast to results of a previous Japanese study. However, examination of a polymorphic site in the 5'-flanking region, within a putative binding motif for the hepatic transcription factor HNF-1, revealed a significantly less frequent distribution of the mutated allele (c2) among the lung cancer patients as compared to controls. It is concluded that major interethnic differences exist in the genetic polymorphism of CYP2E1 and that people carrying the c2 allele might be at lower risk for developing lung cancer.

Base Sequence↗
PubMed1993

Lung inflammatory cells after exposure to mouldy hay.

To investigate the inflammatory cell response after exposure to mouldy hay, guinea pigs were exposed to an aerosol of spores from mouldy hay. Lung wall (LW) and lung lavage (LL) cells were counted after 5 weeks of daily exposures. At 5 weeks both LW and LL macrophages, lymphocytes and neutrophils increased. The LL cell increase was proportionally higher. At 12 weeks, the increase in the number of cells was slightly less than at 5 weeks. After cessation of exposure, macrophages and lymphocytes remained elevated up to 7 days whereas neutrophils rapidly decreased to normal values. This animal inhalation model of early allergic alveolitis could be used to evaluate the importance of different exposure conditions and various agents in the dust.

Aerosols↗
PubMed1993

Bronchial reactivity among cotton workers in relation to dust and endotoxin exposure.

Bronchial reactivity was measured before work among non-smoking female and male workers from carding, spinning, warping and weaving areas in a cotton mill. Airport baggage loaders were used as controls. The amount of dust and endotoxin was measured at the different workplaces. Statistically significant decreases in FEV1 were found between groups of cotton workers at different work sites after administration of the highest accumulated methacholine dose used (1.25 mg). A relationship was found between decreases in FEV1 after methacholine challenge and airborne endotoxin levels but not for dust.

Bronchial Hyperreactivity↗
PubMed1993

Effects of oral and intravenous administration of endotoxin in prepubertal gilts.

The effect of oral intake of endotoxins was studied in 12 prepubertal gilts. The animals were given 30 or 100 mg of ET each in their regular morning feed ration. Blood samples were collected periodically during 24 h and the clinical status, including rectal temperature, was recorded at the same time. Hematological and clinical chemical analyses that included serum bile acids, glutamate dehydrogenase, alkaline phosphatase, calcium, iron, zinc and a blood plasma metabolite of prostaglandin F2 alpha, were done. The animals showed no obvious clinical symptoms following endotoxin feeding. The major findings were increased bile acid and glutamate dehydrogenase values with the most prominent rises being recorded 10-12 h after endotoxin intake. In a later experiment, 6 animals were injected i.v. with endotoxin in doses in the range 0.1-0.5 micrograms/kg b.w. Blood samples were taken and analysed as in the endotoxin-feeding experiment. Within 1 h of injection, all animals showed symptoms such as vomiting, fever and dyspnea. The clinical signs disappeared within 2-5 h. The injections were followed by increases in bile acids, glutamate dehydrogenase and prostaglandin F2 alpha metabolite. To conclude, this study indicates that clinically healthy prepubertal gilts react to ingested endotoxin in feed but that no apparent clinical disturbances ensue.

Animal Feed↗
PubMed1993

Bronchial reactivity, atopy, and airway response to cotton dust.

Studies of cotton textile workers have found an association between atopy and drop in FEV1 over a workshift. We studied the response of previously nonexposed volunteers with and without a history of mild atopy to a 5-h exposure to 1 mg/m3 of respirable cotton dust in a model cardroom. All participants were nonsmokers, had no history of asthma, and had normal spirometry. Twenty atopic subjects gave a personal history of mild respiratory allergy to pollen, dusts, or animals that had been confirmed by a physician. Thirty-two nonatopic subjects had no history of allergy. Spirometry and a methacholine challenge test were performed 1 to 2 days prior to exposure. Spirometry was repeated immediately before exposure to cotton dust; spirometry and a methacholine challenge were performed immediately after exposure. Atopic subjects showed a significantly higher mean serum IgE level to Phadiatop, a screening test to common inhalant allergens, than did nonatopic subjects (mean percent binding, 32.1 versus 1.5; p < 0.001). Atopic subjects had a significantly greater mean fall in FEV1 during exposure (8.3% versus 4.9%, p < 0.05). The difference in FEV1 decline between atopic and nonatopic subjects was similar in magnitude to that reported for workshift FEV1 declines between textile workers with and without mild atopy. Atopic subjects had significantly higher baseline methacholine responsiveness than did nonatopic subjects (26% versus 0% reaching a PD20, p < 0.0005). After cotton dust exposure, there was a significant increase in airway reactivity in both groups (68% versus 20% reaching a PD20, p < 0.0005). For all subjects combined baseline responsiveness was significantly related to the change in FEV1 after exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Effects of noise on mental performance with regard to subjective noise sensitivity.

Objective and subjective effects of moderate levels of recorded traffic noise [Leq = 55 dB(A) and 75 dB(A)] on mental performance were studied in a laboratory setting. A total of 45 subjects (23 males and 22 females) were investigated with respect to subjective noise sensitivity (SNS). Four cognitive tasks were applied involving different psychological functions: Short-Term Memory (STM), Search and Memory 5 (SAM 5) (vigilance), Hidden Figures (HF) (spatial reasoning) and Mental Arithmetic (MA) (parallel processing). Three groups of 15 subjects were defined according to their scores on Weinstein's Noise Sensitivity Scale as tolerant, moderately sensitive or highly sensitive to noise. A similar level of performance was observed in the three groups under quiet conditions [30 dB(A) Leq], but under noisy conditions significant differences (P < 0.05) were seen between them on the STM (words) and MA (total results) tasks, and the lowest performance accuracy was demonstrated by the noise-sensitive subjects. SNS was the primary factor responsible for these differences. There were no significant differences between the groups in respect of the SAM 5 and HF tasks, under either quiet or noisy conditions. Annoyance while performing tasks under noisy conditions was regularly and significantly higher among subjects judged to be noise sensitive on Weinstein's scale, as compared with those judged to have low or moderate SNS.

Adolescent↗
PubMed1992

Acute pulmonary toxicity of inhaled beta-1,3-glucan and endotoxin.

The number of inflammatory cells was studied in lung walls and airways after inhalation of endotoxin or beta-1,3-glucan. In the water unsoluble form, beta-1,3-glucan caused a delayed response in terms of a decrease in macrophages and lymphocytes in the lung wall, 1 to 7 days after exposure but no invasion of neutrophils into the airways. When solubilized in 0.02 N NaOH, the cell response was the same as that observed after exposure to endotoxin.

Administration, Inhalation↗