Giemsa stain applied to deplasticized sections to identify pancreatic islet cells

A new application of the Giemsa stain to demonstrate endocrine cells in deplasticized sections of Epon embedded material is described. Its application to the pancreas of Rana temporaria is illustrated. The technique does not require postfixation with OsO4 and is easily performed in 30 min. It allows the easy identification of three types of endocrine cells (A, B, and D). A cells, preferentially located at the islet periphery, stain purple-blue. B cells, which occupy the interior of the islet, display a lilac color. D cells give a strong purple color; they are located both in the periphery of the islets and scattered among acinar cells. Positive identification of the cell types was made by immunocytochemistry and electron microscopy.     

DQ α and β RFLP reveals the composition of the DQ molecule recognized by T-cell clones

Pst I RFLP, revealed with DQ and DQ probes, was compared with Taq I RFLP using a panel of DR-homozygous cell lines and HLA-typed family members. Taq I patterns, characteristic for each DR-associated DQ and allelic forms, were recognized in the homozygous state and then proven to segregate in the heterozygous members of informative families. The presence of both specific and chains was found to be necessary to form the type of DQ molecule specifically recognized by two alloreactive T-cell clones. Particular and associations also seem to be responsible for some Dw splits of the DRw6-positive cells. Taq I RFLP analysis may be more complex than the Pst I analysis, but is certainly more informative and complete, considering the type of information we were seeking by performing these types of experiments.Abbreviations used in this paper BSA bovine serum albumin - GLO glyoxalase - kb kilobase(s) - LCL lymphoblastoid cell line - MHC major histocompatibility complex - PBL peripheral blood lymphocyte - PLT primed lymphocyte test - RFLP restriction fragment length polymorphism - SDS sodium dodecyl sulfate - SSC standard sodium citrate - SSCP sodium, sodium citrate, sodium phosphate - TBE Tris-borate, boric acid, ethylenediaminetetraacetate (EDTA) - TCGF T-cell growth factor     

An HLA-C-specific DNA probe

Analysis of available nucleotide sequence data for class I HLA genes has established that the seventh intron is one of the gene regions which expresses the highest degree of locus specificity (the percentage sequence divergence between nonallelic genes minus the percentage sequence divergence between allelic genes). We have subcloned short DNA sequences including this region from the HLA-Cw3 gene. Two clones, pC250 and pC800, were tested by hybridizing them at high stringency to a panel of clones containing class I HLA genes. Under conditions permitting a strong hybridization signal with a C-locus gene, pC800 also expressed a weak but significant hybridization to other class I genes, while pC250 appeared to hybridize exclusively to the C-locus gene. Hybridization of the pC250 probe at high stringency to Hind III-digested genomic DNA from a panel of unrelated individuals and homozygous typing cell lines revealed a single band in all cases. However, equivalent hybridization against Eco RI-digested DNA revealed two hybridization bands, one at 7.9 kb which correlated with the serologically defined Cw5 and Cw8 alleles, and one at 7.6 kb which correlated with the Cw1, Cw2, Cw3, Cw4, Cw6, and Cw7 alleles.     

Some aspects of social problems facing conservation in Brazil

There has been growing concern in Brazil for environmental issues in the last two decades. The conservation policies for Amazonia, which still represents the largest portion of forests of the country, are still based on isolated decisions made in the late 1970's. Among these policies there is, for instance, the plan for the establishment of a net of National Parks, proposed by Wetterberg et al. (1), based on the 'Pleistocene refugia' model. These refugia are areas of high species endemism, representing forest islands formed during the dry periods of the Pleistocene age, constituting the center of evolution and dispersal of Amazonian species (2). A number of parks and biological reserves have since been established and the decreese of laws protecting some elements of the fauna have been implemented. In 1979, studies for a more comprehensive plan for the conservation and development of Brazilian Amazonia were carried out in several institutions committed to research in Amazonia. As a result, several documents were handed to the government, but nothing has yet been implemented. Indeed, no environmental policy for Amazonia will succeed without an effective and comprehensive social plan, and the latter has yet to be formulated.     

Interaction between prostacyclin and colchicine on the gastric mucosa of rat in different experimental ulcer models

The effect of prostacyclin and colchicine on the fundic gastric mucosa of adult female Wistar rats was investigated in stress (immobilization) and indomethacin induced ulcer models. Under prostacyclin treatment the ulcer index decreased significantly in both ulcer models. This effect was inhibited by colchicine. The nuclear volume of fundic epithelial cells increased significantly after application of either type of ulcerogenic stimulus. Prostacyclin did not influence the nuclear volume changes in stress ulcer, while it prevented this phenomenon in indomethacin-induced ulceration. Following colchicine treatment the nuclear volume decreased in both ulcer models. After combined prostacyclin and colchicine treatment the nuclear shrinkage remained unaltered in stress ulcer, while in indomethacin ulcer the nuclear volume decreasing effect of the separately administered drugs disappeared after combined treatment. The latter phenomenon was interpreted as an antagonistic interaction between prostacyclin and colchicine.