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Biomedical subjects

W G Pond

Publications and source records attributed to W G Pond.

At least 145 records · Page 8Linked to original sources
PubMed1976

Immunoreactive growth hormone levels in pigs fed protein or energy restricted diets during the postweaning period.

Developmental changes in growth hormone levels during protein or energy malnutrition was studied in weaned pigs. Three or 4 weeks old pigs from control dams were fed a control diet (18% protein), an energy-restricted diet (18% protein) or a low protein diet (6% protein) for 8 weeks. Energy restriction was achieved by feeding the control diet in amounts that allowed very little growth. After the restriction period, all pigs were fed the control diet ad libitum for another 8 weeks. Blood samples were collected at intervals throughout the experiment and the plasma was analyzed for growth hormone by radioimmunoassay. Post weaning protein deprivation resulted in higher growth hormone levels during the restriction period as compared to control pigs or pigs with a restricted energy intake.

Age Factors↗
PubMed1976

Plasma adrenocorticosteroid levels in protein and energy restricted pigs.

Pigs (Yorkshire) were subjected to protein-energy malnutrition in the following manner: 3- or 4-week-old pigs from control dams were fed a control diet (18% protein), an energy-restricted diet (18% protein), or a low protein diet (6% and 3% protein) for 8 weeks. Energy restriction was achieved by feeding the control diet in amounts that allowed some growth, but only to an extent equal to the low protein diet being matched. After the restriction period, all pigs were fed the control diet for another 8 weeks. Blood samples were collected at intervals from the superior vena cava. Plasma samples were analyzed for corticosteroids in all groups and for free cortisol in the controls and 3% protein groups. No significant differences were found for total plasma corticosteroids among all groups. Free cortisol was found significantly higher in the 3% group compared to the controls. An ACTH test was performed with depleted and recovered pigs of the 3% protein group and controls. No differences were found among controls, depleted and recovered pigs.

Adrenal Cortex↗
PubMed1976

Bone pathology in hypervitaminosis D an experimental study in young pigs.

Five groups of 4 weanling pigs were fed a diet with 1.2% calcium and 1.0% phosphorus for 8 weeks with vitamin D3 at 1, 5, 25, 125 and 625 times the recommended levels, respectively. Hypercalcemia and hypophosphatasemia developed rapidly and persisted in Group 5 and developed more slowly but steadily in Group 4. Increasing levels of vitamin D3 influenced progressively and negatively the activity of resorbing osteocytes with osteopetrosis in Groups 2 and 3 and with osteonecrosis in Group 5. Atrophy of osteoblasts further contributed to the osteopenia in Group 5. Cartilage growth activity was arrested in Group 5. The negative effect on the resorbing osteocytes, which finally lead to death of the cells, was ascribed directly to vitamin D3 toxicosis since hypoparathyroidism and hypercalcitonism, both resulting from hypercalcemia, are not known to induce osteonecrosis. Since hypercalemia was finally as severe in Group 4 as in Group 5 and since there was soft tissue calcinosis only in Group 5, the calcinosis was always considered dystrophic, an interpretation supported by the observation that degenerative histologic changes preceded soft tissue calcinosis.

Animals↗
PubMed1975

Effect of dietary Ca and Cd level of pregnant rats on reproduction and on dam and progeny tissue mineral concentrations.

Pregnant Sprague-Dawley rats were used to determine the effects of the addition of 200 ppm of Cd (as CdCl2) to the diet factorially with two levels of dietary Ca (0.07% and 0.96%) on reproductive performance, concentrations of Cd, Cu, Fe, Zn, Ca and Mg in dam liver and kidney and in newborn progeny. High Cd significantly increased liver and kidney Cd, Zn and Ca and decreased liver Fe. High dietary Ca partially protected against accumulation of Cd in liver and kidney but had no effect on concentration of other elements. Number of live or stillborn pups per litter was not significantly affected by diet but high Cd significantly reduced pup birth weight. No grossly abnormal pups were noted. Concentration of Cd in bodies of newborn pups was increased approximately 8.6-fold by high Cd in the diet of dams fed the 0.07% Ca-diet and 3.8-fold by high-Cd in the diet of dams fed the 0.96% Ca diet. Pup, Zn, Cu and Fe contents were significantly decreased and Ca was significantly increased by high-Cd in the maternal diet whereas pup Mg content was unchanged. Maternal Ca intake had no effect on concentration of Zn, Cu, Fe or Ca in newborn pups. The biological importance of the alteration in maternal and fetal tissue concentration of Zn, Cu and Fe by high-Cd maternal diets is unknown.

Animal Nutritional Physiological Phenomena↗
PubMed1973

Lead inclusion bodies in osteoclasts.

Inclusion bodies occur frequently in the nuclei and rarely in the cytoplasm of osteoclasts in pigs with experimental lead poisoning. The light and electron microscope pictures of undemineralized sections are similar to those described for liver cord cells and renal tubular cells.

Animals↗