Inhibition of alpha-glucosidase in cattle by Castanospermum australe: an attempted phenocopy of Pompe''s disease

Pompe's disease is characterised by an absence of lysosomal alpha-glucosidase, but this enzyme is also inhibited by Castanospermum australe seeds. Four calves were fed C. australe seeds at the rate of 0.15 g/kg body weight for periods from 1 to 4 days. Lymphocyte alpha-glucosidase activity was reduced by at least 90%, with the majority of inhibition occurring within 8 h of dosing. Several weeks elapsed before activity returned to normal. Significant inhibition of muscle alpha-glucosidase occurred and the ratio of plasma alpha-glucosidase activity measured at pH 5.6 relative to that at pH 3.7 was depressed. In an attempt to induce Pompe's disease, 2 calves were dosed with 1.2 g C. australe seed/kg body weight/day for 13 months. Lymphocyte and muscle alpha-glucosidase activities were markedly reduced over the entire period of feeding, but the animals showed no clinical signs of disease. Tissue cells were not vacuolated nor did they show any apparent accumulation of glycogen. Despite significant inhibition of alpha-glucosidase in skeletal and cardiac muscle, liver, kidney and brain, it is suggested that there was sufficient residual enzyme to prevent induction of a phenocopy of Pompe's disease.     

Evaluation of Canine Cortical Bone Graft Remodeling

A stable cortical bone fracture model was developed to evaluate the remodeling rate of cortical bone grafts. Samples of cortical bone were harvested with a trephine and press fit into predrilled holes in the femoral diaphyses of four live dogs. The percentages of new bone, unremodeled graft bone, porosity, forming bone surface area, and resorbing bone surface area were determined morphometrically and compared in cortical autografts, cortical allografts sterilized with 84% ethylene oxide (EO), and allografts sterilized with 12% EO. The host-graft interfaces healed without formation of fibrous tissue or cartilage, indicating a stable fracture surface. The amount of new bone formed in cortical autografts and allografts sterilized with 84% EO was significantly greater than the amount of new bone in allografts sterilized with 12% EO. There was no significant difference between the amounts of new bone formed in the allografts sterilized with 84% EO and the cortical autografts. No significant differences were detected in percentages of porosity or bone surface areas.     

Chronological Appearance of Apoptosis in Bovine Embryos Reconstructed by Somatic Cell Nuclear Transfer from Quiescent Granulosa Cells

Efficiency of cloning has remained low and in spite of attempts to improve this technology, many reconstructed embryos do not implant or are lost during early pregnancy. Chromosomal aberrations, deviant gene expression patterns and abnormal regulation of cell death may be involved in this increased early embryonic loss. Here, we investigate the chronological onset of both apoptotic changes in nuclear morphology and DNA degradation [detected by transferase-mediated dUTP nick-end labelling (TUNEL) reaction] in bovine two-cell- to blastocyst-stage embryos. Such embryos were generated either by reconstruction with nuclear transfer from quiescent granulosa cells or by regular in vitro embryo production. Nuclear condensation was observed from the two-cell stage and TUNEL labelling was observed from the six-cell stage in reconstructed embryos, whereas nuclear condensation was evident from the eight-cell stage and TUNEL labelling from the 13-cell stage in embryos derived in vitro. Furthermore, reconstructed embryos displayed elevated ratios of embryos containing apoptotic nuclei at pre-compaction stages and higher indices of apoptotic nuclei in morula and blastocyst stages when compared with in vitro-produced embryos.     

The effects of exposure to water-soluble fractions of crude oil on selected histochemical parameters of the liver of Atlantic croaker, Micropogon undulatus L.

Abstract. Micropogon undulatus L. were sampled from Galveston Bay, Texas, and transported to the research laboratory. Groups of five fish were exposed to 5 and 10% dilutions of the water soluble fraction (WSF) of southern Louisiana crude oil for 1, 3, 7, 14 and 21 days. Selected histochemical parameters of liver sections from control and WSF-exposed fish were evaluated. Glycogen was reduced in amount while glucose-6-phosphate dehydrogenase, lipid and cholesterol were increased in liver sections of WSF-exposed fish. These observations support a hypothesis that exposure to petroleum hydrocarbons increases mixed-function oxidase activity. The alterations were more obvious in sections from fish exposed to the higher level of the WSF. The histochemical parameters appeared most altered in hepatocytes near afferent hepatic blood vessels. These hepatocytes were the first cells of the liver to contact the pollutants.