[Mesothelioma following occupational contact with asbestos].

From 1975 onwards, mesothelioma is by far the most often seen occupational tumour in Switzerland (about 70%). Between 1969 and 1982, there have been 49 cases registered by the SUVA (Schweizerische Unfallversicherungsanstalt, i.e.

Persistent protoporphyrinemia in hereditary porphobilinogen synthase (delta-aminolevulinic acid dehydrase) deficiency under low lead exposure. A new molecular basis for the pathogenesis of lead intoxication.

For several years, a 4-12-fold increase of the upper normal limit in erythrocyte protoporphyrin concentrations persisted in two men 34 and 39 years of age who were chronically exposed to lead. We are dealing with a zinc protoporphyrinemia in both cases, without lead intoxication or anemia. The 34-year-old had been a regular blood donor for 10 years and had already been treated for iron deficiency several times.

Oxygen tolerance of strictly aerobic hydrogen-oxidizing bacteria.

Growth of various bacteria, especially aerobic hydrogen-oxidizing bacteria, in the presence of 2 to 100% (v/v) oxygen in the gas atmosphere was evaluated. The bacterial strains included Alcaligenes eutrophus, A. paradoxus, Aquaspirillum autotrophicum, Arthrobacter spec.

The relationship of the carcinogenic/mutagenic potential of arylamines to their singlet-triplet nitrenium ion energies.

Utilizing intermediate neglect of differential overlap (INDO) and ab initio methodology, trends in the energy differences between the singlet and triplet states for mono- and polycyclic aryl nitrenium ions have been estimated. Calculations reveal an empirical correlation between the energy separation of the singlet and triplet states of the nitrenium ion and the ability of the parent amine to behave as a carcinogen or mutagen. Non-carcinogenic/non-mutagenic arylamines were characterized by nitrenium ions whose singlet states were much less stable than the triplet.

[Place of occupational medicine in the Swiss health service].

Occupational medicine represents an important section of public health. It still has to be developed in Switzerland. Every physician needs basic knowledge of medicine of labour.

[Industrial medical activities of SUVA (Swiss Accident Insurance Agency)].

The group of occupational medicine of the Swiss Accident Insurance Fund (Suva) fulfills functions of standardizing, e.g. setting TLVs, of insurance medicine, i.

Naturally occurring genetic transfer of hydrogen-oxidizing ability between strains of Alcaligenes eutrophus.

Mutants defective in chemolithoautotrophic growth (Aut-) have been isolated from Alcaligenes eutrophus strains H16, N9A, G27, and TF93. Spontaneous Aut- mutants were obtained only with strain TF93. Mutants of the other strains were selected after conventional mutagenesis or treatment with mitomycin.

[Conisation and pregnancy (author's transl)].

Reference is made to experience obtained from specialised outpatient practice in an account of diagnostic and therapeutic approach to pregnant women with pathological cervix smear. Six out of 93 pregnant women were conisised during pregnancy and 41 after delivery. Postpartum primary vaginal hysterectomy was performed on three women with additional gynaecological indication.

Production of superoxide radicals by soluble hydrogenase from Alcaligenes eutrophus H16.

The soluble hydrogenase (hydrogen-NAD+ oxidoreductase, EC 1.12.1.

Efficiency of bovine liver catalase as a catalyst to cleave H2O2 added continually to buffer solutions.

Empirical estimations of H2O2 concentration in a system containing bovine liver catalase and continually supplied with H2O2 were done to evaluate the efficiency of the enzyme to cleave H2O2. It was found that the continuous addition of H2O2 leads to the formation of steady-state concentrations of H2O2 in the medium. At a constant catalase concentration both the level and the duration of the steady state are dependent on the flow rate of H2O2.

Oxygen supply to bacterial suspensions of high cell densities by hydrogen peroxide.

The supply of heterotrophically growing suspensions of Alcaligenes eutrophus PHB-4 with oxygen formed by the continuous addition of H2O2 in the presence of bovine liver catalase was found to be restricted to well-defined conditions. The catalase-H2O2 system proved to be suitable during the growth at low cell densities equivalent to 2 g dry weight/liter. When under these conditions the oxygen concentration was held constant at 1.

[Health hazards caused by wood in Switzerland].

The clinical signs and symptoms of health hazards caused by wood are discussed together with their etiology and pathogenesis. 165 such cases were reported to the SUVA (Swiss Accident Insurance Association) up to the end of 1978. Disorders were most common among workers having the greatest exposure to the fine wood dust produced by tropical woods (in particular during grinding and cutting processes).

Carbon monoxide:methylene blue oxidoreductase from Pseudomonas carboxydovorans.

The enzyme carbon monoxide:methylene blue oxidoreductase from CO autotrophically grown cells of Pseudomonas carboxydovorans strain OM5, was purified to homogeneity. The enzyme was obtained in 26% yield and was purified 36-fold. The enzyme was stable for at least 6 days, had a molecular weight of 230,000, gave a single protein and activity band on polyacrylamide gel electrophoresis, and was homogeneous by the criterion of sedimentation equilibrium.

The regulation of hydrogenase formation as a differentiating character of strains of Paracoccus denitrificans.

Paracoccus denitrificans strains Stanier 381 (DSM 65), Morris (DSM 413), and Vogt 11 (DSM 415) and eleven newly isolated strains were compared with respect to the localization of hydrogenase and its regulation. In all strains hydrogenase was found to be membrane-bound and not able to reduce pyridine nucleotides. The enzyme was inducible in strain 381 and was found only in cells grown with hydrogen as the sole hydrogen donor; in cells grown under mixotrophic or heterotrophic conditions the hydrogenase activity was zero.