A case-control study was conducted in 620 cases of hematological malignancies and in 1,240 age- and sex-matched controls in order to verify the possible association between occupation, toxic substances exposure, and the risk of hematological neoplasias. The results demonstrate that farmers and industrial workers have a significant risk for hematological malignancies. Exposure to asbestos, aromatic hydrocarbons, fertilizers, mineral oils, pesticides, and radiations is associated with a significant increase in the risk for these malignant diseases. These data are in agreement with previously reported data, and require a confirmation in larger, prospective studies.

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A retrospective study was undertaken on onset of symptoms in 667 cases of stroke. All strokes occurred out of hospital. There were 382 males and 285 females, observed from 1971‐1988. The 667 cases of stroke consisted of 508 cases of cerebral infarction and 159 cases of cerebral hemorrhage. The data, analyzed by the single cosinor method, demonstrate a significant circadian, circaseptan, and circannual rhythmicity in the occurrence of stroke. The peaks occur in the morning hours, in the weekend, and in winter. Cerebral hemorrhages do not have a circadian rhythmicity in their occurrence, while they do present circaseptan and circannual rhythmicity. Cerebral infarctions present circadian, circaseptan, and circannual rhythms. No difference was found between males and females. The possible factors involved in temporal distribution of stroke are discussed. These observations could be useful for a better understanding of the pathogenesis and treatment of stroke.

The short-term effects of atenolol and nifedipine on plasma levels of atrial natriuretic peptide (ANP), plasma renin activity (PRA), and plasma aldosterone (PA) were studied in two groups of patients with uncomplicated essential hypertension. Urinary catecholamines, and sodium and potassium excretion were also studied. A group of 20 patients with hypertension, after a wash-out period of at least 10 days, was randomly subdivided into two protocol therapy subgroups. One group (six men and four women) received atenolol (100 mg/d), and the other group (six men and four women) received nifedipine (30 mg/d). Circulating plasma levels of ANP, PRA, and PA were determined by radioimmunoassay, and other variables were determined by routine laboratory techniques before therapy and at day 3 and day 7 after the treatment began. Arterial blood pressure and heart rate were monitored during the study. Both drugs reduced arterial blood pressure (P less than .001) significantly. The atenolol therapy decreased heart rate (P less than .001), increased plasma ANP levels and urinary catecholamine excretion, and decreased PRA and circulating PA levels. Nifedipine treatment did not modify plasma ANP values, whereas it increased PRA and PA circulating levels and urinary catecholamine excretion. No differences were shown for urinary volume, urinary sodium, and potassium excretions during the two different treatments. These findings suggest that the increased plasma ANP levels could contribute to the antihypertensive effects of the beta-adrenoreceptor blockers, by a reduction in PRA and PA levels and a vasodilatative effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Background Because airway calibre shows a circadian rhythm and since exposure to passive smoking reduces lung function this study was undertaken to investigate whether passive smoking affects the circadian rhythm of peak expiratory flow (PEF) in schoolchildren. Methods Twenty schoolchildren (12 boys and 8 girls, aged 10-11 years) exposed to passive smoking were matched for sex, age, and height with 20 children who had not been exposed to cigarette smoke. Exposure to passive smoking was assessed by questionnaire and by urinary cotinine concentrations. A portable spirometer was used to measure PEF at 16:00, 20:00,