Iron status in the acute phase and six weeks after myocardial infarction

In a case-control study of 84 myocardial infarction patients and 84 population controls we investigated the association between iron status parameters and myocardial infarction during the acute phase and after six weeks. Immediately after the infarction mean ferritin levels were significantly higher, whereas iron levels and iron saturation of transferrin were significantly lower in cases than in controls. Six weeks after the infarction, serum iron levels were still significantly lower in cases than in controls. Neither serum ferritin levels nor serum iron levels did show a clear association with the size of the ischemic tissue damage as estimated by creatine phosphokinase levels. Our results indicate that serum ferritin and iron levels are influenced by the traumatic effects of the myocardial infarction. Possibly, these transient changes are an acute effect, as seen in infections. An increased uptake of iron in the reticulo-endothelial system for synthesis of ferritin, may account for the lowered serum iron level and the iron saturation of transferrin.     

Ritual production of environmental history among the Arawakan Wakuénai of Venezuela

This essay examines ritual and ceremonial activities among the Arawakspeaking Wakuénai of the Venezuelan Amazon as processes of constructing power relations in changing historical and ecological conditions. Ritual evocations of the vertical dimension of power relations between mythic ancestors and human descendants adapt local populations to conditions of relatively severe stress, such as epidemics and scarcity of fish in long wet seasons. Other rituals evoke the horizontal dimension of power relations between affinally-related groups as a way of expanding the local descent group in conditions of lowered stress. These two ways of exercising ritual power link human populations to specific natural habitats and provide flexibility needed to adjust to demographic and other historical changes. Through ritual performances, the Wakuénai transform the natural environment into a cultural landscape of socialized objects and, conversely, remember the history of political relations among peoples through spirit-naming of natural species, objects, places, and geographic landmarks.     

Gaps in the canopy: the missing dimension in vegetation dynamics

Canopy gaps are important as entry points for new genotypes and new species into many types of vegetation, yet little is known about them in any type of vegetation but forests. Forest gaps are too large for manipulative experiments to be readily undertaken, and hitherto grassland gaps have been too small to be easily mapped. Preliminary results from mapping small (>1 cm) grassland gaps with a new fibre-optic device suggest that experiments need to be performed at a smaller physical scale than has hitherto been achieved.     

The human heat-shock genes HSPA6 and HSPA7 are both expressed and localize to chromosome 1.

HSPA6 is a member of the human heat-shock protein gene family, encoding a basic 70-kDa protein, with unique induction characteristics (Leung et al., 1990, Biochem. J. 267: 125-132). Hybridization analyses with a somatic cell hybrid DNA panel localized the gene to chromosome 1q. The highly related HSPA7 DNA sequence (Voellmy et al., 1985, Proc. Natl. Acad. Sci. USA 82: 4949-4953) colocalized. Both HSPA6 and HSPA7 represent functional genes, as determined by analyses of mRNA from heat-shocked human cells using specific oligonucleotides, although their pattern of expression differed. Neither mRNA was detected in the absence of heat stress. A BamHI polymorphism in the HSPA7 gene was present in a predominantly Asian population.