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L L David

Publications and source records attributed to L L David.

56 records · Page 4Linked to original sources

Ultrastructural study of liver fibrosis in turkeys fed diets containing rapeseed meal.

Livers of turkeys fed low and high glucosinolate rapeseed meal diets for 16 weeks were examined ultrastructurally. Hepatocytes from birds fed on Tower rapeseed meal (0.15 mg of glucosinolate per g) showed a mild accumulation of lipid droplets and an apparent increase in lysosomes and microbodies. The parenchymal cells of the livers of turkeys fed on Target Rapeseed meal (9.50 mg of glucosinolate per g) exhibited varying degrees of degenerative change: dilation of endoplasmic reticulum, swelling of mitochondria with fragmentation and loss of cristae, presence of autophagic vacuoles, myelinoid bodies, electron-dense lipidlike droplets, vesiculation of cytoplasm and necrosis of the hepatocytes. The electron-dense lipidlike bodies were most frequent at the biliary pole. Sinusoids near the degenerating hepatocytes were often disrupted and perisinusoidal mesenchymal cells in the area showed distended cisternae of granular endoplasmic reticulum. Such cells or fat-storing cells were frequently seen in the vicinity of proliferated collagen fibrils and degenerating hepatocytes. These observations suggest that degenerative alterations of hepatocytes accompanied or preceded the development of fibrosis in turkeys fed rapeseed meal high in glucosinolate.

Animal Feed↗

Role of calcium in selenium cataract.

The purpose of this research was to test the role of certain minerals in the formation of cataract caused by an overdose of selenium. Several pieces of information indicated that lenticular calcium may play an important role in selenite cataractogenesis: 1) Lens calcium concentrations in selenite treated rats were increased more than 5-fold, and the increase in lens calcium was localized in the nucleus. 2) Lens calcium concentrations were elevated at least one full day before actual formation of nuclear cataract, but serum calcium levels were not changed. 3) In older rats not susceptible to selenite cataract, lens calcium was not significantly increased. 4) No evidence was found for a generalized disruption in lens permeability, since no major changes in lens water, sodium, and potassium levels were observed, and 5) when levels of calcium observed in selenite cataract were added to solutions of soluble proteins from rat lenses, light scattering was increased. Selenium-overdose cataracts may provide an important model for studies on the role of calcium in cataractogenesis.

Age Factors↗