Biomedical subjects

O Dunin-Borkowski

Publications and source records attributed to O Dunin-Borkowski.

3 recordsLinked to original sources

PubMed1993

Blood gases, pH and hematology of montane and lowland coot embryos.

Blood gases, air cell-blood gas differences, blood pH, and hematology were compared in embryonic coots (Fulica americana peruviana) at 4150 m and sea level in Peru. Neither arterialized nor venous O2 tensions differed significantly between montane and lowland groups but blood CO2 tensions of the two groups differed significantly. The air cell PO2-arterialized blood PO2 difference of montane eggs was less than half the value in lowland eggs. Both arterialized and venous CO2 tensions differed substantially between montane and lowland groups. Despite these differences, plasma pH at both altitudes was statistically indistinguishable, due in part to variation in plasma [HCO3-]. Hematocrits of montane embryos were significantly higher than that of their lowland counterparts.

Altitude↗

PubMed1993

Integrins and morphogenesis.

The Drosophila position specific (PS) integrins consist of two cell surface heterodimers, PS1 (alpha PS1 beta PS) and PS2 (alpha OS2 beta PS), which are expressed on complementary sides of attachments between cell layers and are essential for these attachments. Current evidence suggests that the PS integrins bind to components of the extracellular matrix, similar to the majority of vertebrate integrins, but specific Drosophila ligands have not yet been identified. In the embryo PS1 is found on the surface of the epidermis and endoderm, while PS2 is restricted to the mesoderm. The integrins are concentrated at the sites where the somatic muscles attach to the epidermis and at the interface between the visceral mesoderm and the endoderm. In myospheroid mutant embryos, which lack the beta PS subunit, the adhesion between the mesoderm and the other cell layers fails. The PS integrins are also required for the adhesion of the dorsal to the ventral surface of the wing during metamorphosis. PS1 is expressed on the basal surface of the dorsal cells and PS2 is expressed on the ventral cells. Loss of PS integrin function in the wing results in balloon shaped wings because of the failure of the two surfaces of the wing blade to adhere to each other. These and other aspects of the phenotypes of mutations in the genes encoding the PS integrins indicate that integrins play an important role in the adhesion of different cell layers to each other and thus an essential role in the morphogenesis of the organism. The use of extracellular matrix receptors in this role may aid in keeping the different cell layers distinct.

Animals↗

PubMed1991

Metabolic effects of cyanate on mice at sea level and in chronic hypobaric hypoxia.

In order to evaluate the toxic effects of Sodium Cyanate (NaOCN), it was orally administered to growing mice at sea level (SL-CN) and to mice chronically exposed to intermittent hypobaric hypoxia (IHH-CN). The effects on body weight, in-vivo O2 consumption (VO2) and the respiratory function of liver mitochondria were evaluated. At sea level, the animals on cyanate lost weight in contrast with the controls that gained weight. When exposed to IHH, the controls lost weight and the animals on cyanate regained weight. After 2 months observation the weights of the IHH-CN and IHH-C were similar. The VO2 after one month of treatment was similar in the SL-C and in the SL-CN but it was lower in the IHH-CN when compared with IHH-C. The substrate-stimulated respiration of isolated liver mitochondria (ST4) was not affected by NaOCN, but the ADP-stimulated respiration (ST3) was reduced. The ratio ST3/ST4 (RCR) was also lower. These changes were present in both SL and in IHH and were much larger after three months of treatment. The toxic effects of chronic administration of NaOCN are discussed.

Administration, Oral↗