Morphological and Chemical Mechanisms of Elongated Mineral Particle Toxicities

Much of our understanding regarding the mechanisms for induction of disease following inhalation of respirable elongated mineral particles (REMP) is based on studies involving the biological effects of asbestos fibers. The factors governing the disease potential of an exposure include duration and frequency of exposures; tissue-specific dose over time; impacts on dose persistence from in vivo REMP dissolution, comminution, and clearance; individual susceptibility; and the mineral type and surface characteristics. The mechanisms associated with asbestos particle toxicity involve two facets for each particle's contribution: (1) the physical features of the inhaled REMP, which include width, length, aspect ratio, and effective surface area available for cell contact; and (2) the surface chemical composition and reactivity of the individual fiber/elongated particle. Studies in cell-free systems and with cultured cells suggest an important way in which REMP from asbestos damage cellular molecules or influence cellular processes. This may involve an unfortunate combination of the ability of REMP to chemically generate potentially damaging reactive oxygen species, through surface iron, and the interaction of the unique surfaces with cell membranes to trigger membrane receptor activation. Together these events appear to lead to a cascade of cellular events, including the production of damaging reactive nitrogen species, which may contribute to the disease process. Thus, there is a need to be more cognizant of the potential impact that the total surface area of REMP contributes to the generation of events resulting in pathological changes in biological systems. The information presented has applicability to inhaled dusts, in general, and specifically to respirable elongated mineral particles

HFE C282Y and H63D in adults with malignancies in a community medical oncology practice

BACKGROUND: We sought to compare frequencies of HFE C282Y and H63D alleles and associated odds ratios (OR) in 100 consecutive unrelated white adults with malignancy to those in 318 controls. METHODS: Data from patients with more than one malignancy were analyzed according to each primary malignancy. For the present study, OR ≥2.0 or ≤0.5 was defined to be increased or decreased, respectively. RESULTS: There were 110 primary malignancies (52 hematologic neoplasms, 58 carcinomas) in the 100 adult patients. Allele frequencies were similar in patients and controls (C282Y: 0.0850 vs. 0.0896, respectively (OR = 0.9); H63D: 0.1400 vs. 0.1447, respectively (OR = 0.9)). Two patients had hemochromatosis and C282Y homozygosity. With C282Y, increased OR occurred in non-Hodgkin lymphoma, myeloproliferative disorders, and adenocarcinoma of prostate (2.0, 2.8, and 3.4, respectively); OR was decreased in myelodysplasia (0.4). With H63D, increased OR occurred in myeloproliferative disorders and adenocarcinomas of breast and prostate (2.4, 2.0, and 2.0, respectively); OR was decreased in non-Hodgkin lymphoma and B-chronic lymphocytic leukemia (0.5 and 0.4, respectively). CONCLUSIONS: In 100 consecutive adults with malignancy evaluated in a community medical oncology practice, frequencies of HFE C282Y or H63D were similar to those in the general population. This suggests that C282Y or H63D is not associated with an overall increase in cancer risk. However, odds ratios computed in the present study suggest that increased (or decreased) risk for developing specific types of malignancy may be associated with the inheritance of HFE C282Y or H63D. Study of more patients with these specific types of malignancies is needed to determine if trends described herein would remain and yield significant differences

α 1‐Antitrypsin phenotypes in chronic active hepatitis

Abstract α‐Antitrypsin (Pi) phenotypes were determined in 58 Caucasian patients with chronic active hepatitis, in whom there was no evidence for a specific aetiological factor. Pi allele and gene frequencies were compared with frequencies in 1007 Australian Caucasian blood donors. There was an increased frequency of the M1M3 phenotype in chronic active hepatitis patients. In contrast to other studies, there was no increase in the frequency of the MZ phenotype. The chronic hepatitis patients had a gene frequency of 0.034 for Pi Z, compared to 0.012 in blood donors. The difference is not statistically significant. The Pi Z group consisted of one homozygous Pi Z patient, previously diagnosed as having chronic active hepatitis and cirrhosis due to α‐antitrypsin deficiency, and only two heterozygous Pi Z subjects. This study fails to confirm a major association between chronic active hepatitis and heterozygous Pi Z phenotypes. Copyrigh