Respiratory health among bleachery workers exposed to ozone and chlorine dioxide

OBJECTIVES: This study investigated the possibility of occupational exposure to ozone increasing the risk of obstructive airway disease among bleachery workers. : Bleachery workers (N = 129) from two Swedish pulp mills using ozone for bleaching were studied together with referents (N = 80) from adjacent paper mills. The pulp mills had previously used chlorine dioxide as the bleaching agent. Testings included spirometry, methacholine challenge testing, and questionnaires. Area samplings showed sporadic ozone levels exceeding 0.9 ppm. RESULTS: There was a greater prevalence of wheezing (25%) among the bleachery workers with a history of gassings (from ozone, chlorine, or sulfur dioxide) than among those without gassings (18%) and among the referents (13%). Among the current smokers the fraction with a slightly increased bronchial responsiveness to methacholine was greater among the bleachery workers reporting gassings than among those that had not been gassed. For the period from 1992 to 1996, when the mills were using ozone, there was an increased incidence rate of wheezing among the workers in the bleachery (incidence rate ratio 2.3, 95% confidence interval 1.6-5.8). CONCLUSIONS: Repeated exposure to irritants increases the risk of asthma-like symptoms. This finding reinforces the view that repeated peak exposures to irritants must be prevented in pulp mills.     

Characterization of Mechanical Effects and β-Adrenoceptor Binding of Prenalterol in Rat Myocardium

Abstract: The partial β-agonist prenalterol has been found to differ from the full agonist isoprenaline in some aspects of its cardiac action. We therefore studied in rat myocardium whether prenalterol elicited the same qualitative changes of the contraction-relaxation cycle as was previously found for isoprenaline. We also measured binding of prenalterol to β-adrenoceptors. Prenalterol augmented relaxation more than contraction and thus evoked the same qualitative changes of the contraction-relaxation cycle as did isoprenaline. However, the response developed slowlier than that to isoprenaline, and the effect on relaxation followed a more protracted time course than the effect on contraction. Prenalterol bound non-selectively to β₁- and β₂-adrenoceptors in both heart and lung broken cell preparations. pK_d for binding to β-adrenoceptors and pD₂ values for functional effects in heart were similar, i.e. prenalterol had to occupy half the amount of β-adrenoceptors in order to evoke half-maximal functional effects. The non-selective α-blocker phentolamine potentiated the effects of prenalterol on contraction, but did not change the equilibrium binding of prenalterol to cardiac β-adrenoceptors. Phentolamine did not change the potency and efficacy of isoprenaline. Thus, although prenalterol qualitatively evoked the same response as isoprenaline, it also exhibited some properties which differed.     

A Clinical and Immunological Study of Allergy to Hen's Egg White

The occurrence of proteins cross-reacting with allergens in hen's egg white was studied in turkey, duck, goose and seagull egg whites, in hen egg yolk, and in hen and chicken sera and flesh. The study was based upon quantitative immunoelectrophoretic techniques. The different egg whites were all found to contain proteins cross-reacting with most of the allergens in hen's egg white, but the degree of cross-reactivity varied considerably among the various egg whites. All egg whites contained proteins able to bind human IgE-antibody in the sera of patients with allergy to hen's egg white. Several proteins cross-reacting with allergens in hen's egg white were also detected in egg yolk and in hen and chicken sera and flesh. Clinical implications of the results are discussed.     

Treatment of caries and periodontitis in Sweden in 1974–77

Abstract During 1974 and 1975 a sample of individuals in Sweden between 20 and 60 years were interviewed about dental care habits. 938 oft them were then clinically examined. An estimation of the time needed for treatment of dental caries and periodontitis was based upon the clinical examination. Dental status and the estimated treatment time were then related to the dental care carried out during one period of 18 months and one of 48 months after the clinical examination. For these calculations, information on dental care was acquired from the patient register of the National Social Insurance Board. The results derived from the analyses showed that the requisite time for treating caries related well to the treatment executed. On the other hand the time for treating periodontal disease showed a poorer agreement with what could have been expected from the clinical periodontal status. The treatment time devoted to periodontal disease was considerably higher in the metropolitan areas, with their higher density of dentists, than in other parts of Sweden. Thus, dental care in Sweden between 1974 and 1978 concentrated primarily on restorative procedures while a progression of periodontal disease was largely ignored by dental practitioners.     

Prenatal development of brown adipose tissue in man. A morphometric and biomathematical study

In a series of 110 liveborn infants who died within 24 h of birth, and six 14- to 17-week-old fetuses, the development of perirenal brown fat was studied by morphometric and biomathematical methods. Brown fat was present at the 20th week of age and, taking as index of maturity the population of multilocular adipocytes, its development progressed according to a 3-parametric logistic growth function, with a half-time of 26 weeks and a tendency to asymptotic stabilization by the 35th week. Unilocular adipocytes appeared early and their low percentage (10.9%) remained relatively stable. Brown fat development in 75% of the cases of small-for-dates corresponded to that of infants with matched postconceptional age but appropriate birth weight. Abnormal cases presented whether a persistence of immature patterns or an unusual predominance of unilocular cells. No changes due to lipolysis were detected in any case.     

Escherichia coli endocarditis of the aortic valve with formation of a paravalvular abscess cavity

A 42-year-old male with a history of chronic aortic valve disease and urethra stenosis, was admitted with fever, dysuria, and vomiting. Escherichia coli (E. coli) was cultured from blood and urine. Repeated transesophageal echocardiographic studies performed during the early phase of the hospitalization did not exclude the possibility of infective endocarditis. A definite diagnosis was, however, not established until 6 weeks after admission. At that time a large paravalvular aortic abscess cavity had developed and urgent surgery was necessary. A possible explanation for the delayed diagnostic evaluation was the low level of suspicion, as the septicemia was believed to originate from the urinary tract, without involvement of other organs. The possibility of endocarditis due to E. coli should be considered, especially in subjects with underlying cardiac valve disease, despite an alternative source of septicemia and despite the rarity of this condition. Frequent echocardiographic studies are recommended since extensive tissue destruction may occur without any striking symptoms.