Exposures and mortality among chrysotile asbestos workers. Part I: exposure estimates.

A detailed study of plant processes and dust control methods over the period 1930-1975 was conducted in an asbestos textile plant processing chrysotile. Linear statistical models for reconstructing historic dust exposure levels, taking into account textile processes, dust control measures, and job assignments, were developed. Parameters of these statistical models were estimated using 5,952 industrial hygiene sampling measurements covering the period 1930-1975.

A comparison of the logistic risk function and the proportional hazards model in prospective epidemiologic studies.

The logistic regression and proportional hazards models are each currently being used in the analysis of prospective epidemiologic studies examining risk factors in chronic disease applications. The advantages and disadvantages of each are yet to be fully described. However, a theoretical relationship between the two models has been documented.

Spin-trapping studies on the free-radical products formed by metabolic activation of carbon tetrachloride in rat liver microsomal fractions isolated hepatocytes and in vivo in the rat.

1. The metabolic activation of carbon tetrachloride to free-radical intermediates is an important step in the sequence of disturbances leading to the acute liver injury produced by this toxic agent. Electron-spin-resonance (e.

Brain and central nervous system cancer mortality in U. S. rubber workers.

Since 1963 the observed mortality experience of BCNS cancers among rubber workers appears to be very comparable to that expected. A possible exception to this statement is the experience of one plant in Akron, Ohio, reported by Monson and Nakano. Excesses in earlier years may also be localized to one or two companies.

Practical considerations for approximating relative risk by the standardized mortality ratio.

The standardized mortality ratio is a widely used and often criticized summary statistic for studies of occupational mortality. In this paper the authors discuss practical conditions under which relative risk can reasonably be approximated by the standardized mortality ratio. When the true relative risk is greater than 100%, the standardized mortality ratio overestimates relative risk no matter how small the mortality rates or how short the age bands utilized in the analysis.

A method for monitoring the fertility of workers. 2. Validation of the method among workers exposed to dibromochloropropane.

A method has been developed for monitoring industrial workers and others exposed to environmental agents which may impair fertility. National birth probabilities specific for maternal birth cohort, age, parity, and race are used to derive expected fertility. Observed fertility is obtained by questionnaire.

A method for monitoring the fertility of workers. 1. Method and pilot studies.

A method has been developed for monitoring male and female industrial workers and other persons exposed to environmental agents which may impair fertility. The essential feature of the method is its ability to distinguish the potential effects of occupational exposure from a multitude of other factors known to affect fertility. Information is collected primarily through use of a questionnaire which take less than three minutes to complete and can be administered to persons of either sex.

Worker exposures to chemical agents in the manufacture of rubber tires: solvent vapor studies.

Environmental sampling surveys have been conducted in ten large tire manufacturing plants across the U.S. to characterize the nature and intensity of current exposure to solvent vapors.

Worker exposure to chemical agents in the manufacture of rubber tires and tubes: particulates.

The Occupational Health Studies Group industrial hygiene studies at a group of 14 tire and tube manufacturing plants chosen to represent a cross-section of the industry include numerous evaluations of potential exposure to airborne particulate matter. Results of these environmental particulate sampling studies are reported by plant and by occupational groups within plants. High volume, open face and cyclone samplers were employed to evaluate both personnel and area particulate concentrations.

The relative electron affinities of the alpha and beta chains of oxyhaemoglobin as a function of pH and added inositol hexaphosphate. An electron spin resonance study.

Exposure of aqueous glasses of oxyhaemoglobin to 60Co gamma-rays at 77K results in electron addition to the FeO2 unit, the ESR spectrum for the alpha-chain electron adduct being well separated from that for the beta-chain. The relative yields of these two centres has been measured in the pH range 4.5 to 8.

Electron addition to the active site of Cancer magister haemocyanins. An ESR study of cu(II) centres after gamma-radiolysis.

Exposure of aqueous glasses of Cancer magister haemocyanin to 60Co gamma-rays at 77 K results in a novel paramagnetic centre with ESR features showing hyperfine coupling to one strongly coupled 63/65 Cu nucleus and possibly one weakly interacting 63/65 Cu nucleus. Addition of electron scavengers showed that this centre is formed by electron addition. It is suggested that addition occurs at Cu2+-O2-Cu2+ units to give Cu2+-O2Cu+ centres.

Electron capture at the iron-oxygen centre in single crystals of oxymyoglobin studied by electron spin resonance spectroscopy.

Exposure of single crystals of oxy-myoglobin to 60Co gamma-rays at 77 K results in electron addition to the Fe-O2 units. The resulting ESR spectrum has been analysed to give the principal values and directions for the g-tensor of this unit. The results suggest that the dioxygen ligand is strongly tilted, the direction of tilt being close to one of the bisectors of the N-Fe-N bond angles.

The light-induced carotenoid absorbance changes in Rhodopseudomonas sphaeroides: an analysis and interpretation of the band shifts.

An analysis has been made of the spectrum of the carotenoid absorption band shift generated by continuous illumination of chromatophores of the GlC-mutant of Rhodopseudomonas sphaeroides at room temperature by means of three computer programs. There appears to be at least two pools of the same carotenoid, only one of which, comprising about 20% of the total carotenoid content, is responsible for the light-induced absorbance changes. The 'remaining' pool absorbs at wavelengths which were about 5 nm lower than those at which the 'changing' pool absorbs.

Chronic diseases in the rubber industry.

An overview is presented of epidemiologic studies of chronic diseases in the rubber industry. Analyses of the mortality experience during the period 1964-1972 of workers age 40-64 and retirees age 65-84 of two large rubber and tire manufacturing companies consistently disclosed excesses of deaths attributed to leukemia and lymphosarcoma, and for cancers of the stomach, large intestine, and prostate. The relation of site-specific malignancies to work histories and grouped occupational titles as surrogate measures of work-related exposures to possible carcinogens is described.

Water structure and hydration.

Possible structures adopted by bulk water are discussed with special reference to the possible presence of monomeric water and the detection of 'free' -OH groups. The way in which water tends to accommodate small hydrophobic molecules is considered, with particular reference to the clathrate theory and the phenomenon of 'structure making'. Cage-pairing and cage-sharing processes are described.