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J Aron

Publications and source records attributed to J Aron.

5 recordsLinked to original sources
PubMed1987

Asbestos and asbestos-related disease: the South African case.

The asbestos industry in South Africa has suffered a decline in production, employment, and sales over the last few years. This mirrors the state of the industry internationally. In South Africa this has more to do with the economic recession than with legislative restrictions on asbestos use. New information has become available on the extent of asbestos-related diseases in South Africa. In this article, we outline developments in labor organization in the asbestos industry, and discuss the marked lack of control of asbestos, the inadequate state compensation system, and the difficulties facing labor. After describing recent improvements won by trade unions, mainly in the transnational corporation sector, we discuss the implications for industry, labor, and control of the asbestos hazard.

Asbestos↗
PubMed1987

Cancer risk-assessment models: anticipated contributions from biochemical epidemiology.

Uncertainties in quantitative assessment of cancer risk limit the scientific role of this activity in the policy and regulatory debate on cancer control. Risk-assessment strategies and models are highly dependent on the nature and quality of the data available. However, accumulating laboratory and epidemiologic studies that are shedding new light on mechanisms of carcinogenesis have not yet been integrated into current risk-assessment models. Future developments in risk assessment may, therefore, be anticipated by considering the type of epidemiologic data that may soon be generated. Three important areas of epidemiologic and biochemical research should reduce some of the uncertainty in quantitative risk assessment by making it possible to: identify stages of the disease process through precursor lesions, biochemical markers, and to determine at which stage the carcinogen acts; identify subpopulations that are at enhanced or reduced susceptibility to carcinogenic influences; and obtain additional and refined indices of dose. Much of this research is being called "biochemical epidemiology." Strategies for incorporating these newly generated data into regulatory decisions vary from developing new mechanistically based mathematical models to applying existing models to biologically distinct subpopulations.

Carcinogens↗
PubMed1986

Hemes and hemoproteins. 1: Preparation and analysis of the heme-containing octapeptide (microperoxidase-8) and identification of the monomeric form in aqueous solution.

The heme-octapeptide from cytochrome c, Microperoxidase-8 (MP-8), was prepared by peptic and tryptic digestion of horse heart cytochrome c and purified by gel permeation chromatography in about 50% yield. Conditions for the identification of MP-8 by TLC and analysis by HPLC are described. Study of the concentration-dependence of the absorption spectrum showed that at concentrations of less than or equal to 2.5 X 10(-5) M in aqueous solution at pH 7, 25 degrees C and mu = 0.1, MP-8 exists as an equilibrium mixture of monomers and dimers with KD = 1.17 +/- 0.02 X 10(5) M-1, decreasing to 1.21 +/- 0.02 X 10(4) M-1 and 2.16 +/- 0.21 X 10(3) M-1 in 20% and 50% (v/v) methanol:water mixtures, respectively. Comparison of the Soret region spectrum of monomeric MP-8 with other hemoproteins suggests that it is six-coordinate in aqueous solution with water and His as axial ligands.

Animals↗
PubMed1985

Does plasma transferrin regulate iron absorption?

It has been suggested that transferrin that has recently donated its iron to receptor sites is 'activated' to take up iron more avidly from donor tissues. The hypothesis was tested in vitro in a system in which use was made of the different electrophoretic mobilities of normal and desialated transferrin. Recently desaturated transferrin and native apotransferrin were added in equal amounts to a solution of radioactive ferric citrate to produce various end saturations. The resultant mixture was electrophoresed on 5.4% polyacrilamide gel, which was then sliced and counted for 59Fe counts. The size of the 2 radioactive peaks was then compared and expressed as a ratio. Using this in vitro system no supporting evidence could be found for the hypothesis that diferric transferrin which has just donated its iron is able to bind available iron more avidly than native apotransferrin.

Apoferritins↗