Biomedical subjects

M Hidiroglou

Publications and source records attributed to M Hidiroglou.

At least 73 records · Page 4Linked to original sources

PubMed1988

Binding of selenium-75 to blood and liver cytosolic proteins in the preruminant calf.

Labeled selenite (75Se) administered to calves in milk replacer, containing .2 or 5 ppm Se, was rapidly absorbed with peak blood 75Se at 6 h. Gel filtration and dialysis treatment of plasma and erythrocyte hemolysates showed that initially 75Se was transported in blood as 75SeO3= or loosely bound to plasma and erythrocyte proteins. At high Se intake, albumin became a transport protein for some of the plasma 75Se, and proportionately more blood radioactivity was carried in the erythrocytes. At 72 h after dosing, most plasma 75Se was tightly bound to protein in glutathione peroxidase fraction with low peroxidase activity, possibly Se transport protein. At 72 h, distribution of 75Se in erythrocyte was 35 to 40% in glutathione peroxidase, 50% in hemoglobin, and 5% in a selenite plus selenopolypeptide fraction. Erythrocyte peroxidase activity was mostly in the glutathione peroxidase fraction (57%) and hemoglobin (38%). Molecular weight estimate for erythrocyte glutathione peroxidase was 84,200 daltons; about 90% of blood peroxidase activity was in erythrocytes. High Se intake had no marked effect on distribution of 75Se among liver cytosolic proteins. About 35% of 75Se was in glutathione peroxidase fraction, having most of the peroxidase activity, 25% in void volume, 11 to 18% in a selenite plus selenopolypeptide fraction, and small amounts in selenoproteins of about 12,000 and 50,000 daltons.

Animals↗

PubMed1988

Evaluation of a long-acting selenium and copper preparation for intraruminal administration to cattle.

An intraruminal, soluble glass bolus containing selenium (Se) and copper (Cu) was evaluated for improving the Se and Cu status of pregnant cows and their calves. In the cows, there was a marked increase in the Se status following treatment with the soluble glass bolus. In the untreated cows, Se concentration in the blood (27-31 ng/g) as well as milk (5.1-6.8 ng/ml) remained low which was indicative of Se-deficiency. In the treated cows, the soluble glass bolus administration produced higher blood and milk Se concentrations, which were increased during the whole experimental period (10 months). In calves born from soluble glass treated cows, blood Se (11-28 ng/ml) and Cu (0.43-0.82 microgram/ml) concentrations were higher (except at birth for Cu) than in those from the untreated cows. Despite these differences, the status of the calves born from the treated cows was still low in both Se and Cu.

Animals↗

PubMed1987

Vitamin E kinetics in sheep.

1. Kinetics of physiological doses of D-alpha-[5-Me-3H]tocopherol (200 microCi) administered to twenty-four sheep were studied using one of four routes: intravenous, oral (capsules), intraruminal and intramuscular. 2. Blood samples were withdrawn from the jugular vein periodically for 96 h after the intravenous and oral administrations, for 168 h after the intraruminal administration and for 216 h after the intramuscular administration. 3. The study indicated that the biological availability of alpha-tocopherol followed the order intravenous greater than intramuscular greater than oral greater than intraruminal. 4. The rate of elimination was in the order intravenous greater than oral greater than intraruminal approximately intramuscular. 5. The intravenous route was fitted with a three-compartment model, whereas the other routes exhibited a good fit for either a one- or two-compartment model.

Administration, Oral↗

PubMed1987

Kinetics of intravenously administered 25-hydroxyvitamin D3 in sheep and the effect of exposure to ultraviolet radiation.

This report describes studies of 25-hydroxyvitamin D3 (25OHD3) kinetics in 10 yearling crossbred wethers (40 to 52 kg body weight) administered [3H] 25-hydroxyvitamin D3 [( 3H] 250HD3). The wethers were divided into two groups of five before dosing with the labeled compound: Group 1 wethers were exposed 2 h daily for 8 to 10 wk to ultraviolet radiation from fluorescent sunlamps. Plasma 250HD3 increased from 13 to 31 ng/ml by d 25 and then remained at a steady-state concentration until d 70. In the non-ultraviolet-exposed wethers (Group 2), plasma 250HD3 averaged 13.2 ng/ml and did not change over the course of the experiment. Six weeks after the start of the experiment three wethers from each group were injected intravenously with 50 microCi of [3H]250HD3, and the other two wethers from each group were similarly dosed 2 wk later. Blood was drawn at suitable time intervals for up to 240 h post-dosing. The kinetic data were satisfied by curve-fitting the data to a two-compartment, pharmacokinetic mathematical model. Individual and mean values for these kinetic analyses are presented with their statistical analyses. Physiological half-life of the tritiated 2500 HD3 in wethers exposed to ultraviolet irradiation was 388 +/- 26.4 h (means +/- SE); in the control it was 393 +/- 29.6 h (P greater than .05). In the wethers exposed to ultraviolet the elimination and clearance rates of 250HD3 were significantly greater than in the control wethers. A two-compartment model provided an acceptable description of 250HD3 disposition kinetics in wethers. Turnover rate constants did not seem to change, but changes were due to increased pool size in the irradiated wethers.

Animals↗

PubMed1987

Effect of intraruminally administered, selenium soluble-glass boluses on selenium status in cows and their calves.

Intraruminal selenium soluble-glass boluses were administered by balling gun to 65 of 125 crossbred beef cows (Shorthorn X Charolais) during the last trimester of pregnancy. Elevated (P less than .01) whole blood glutathione peroxidase (GSH-Px) concentrations were observed monthly for the next 10 mo following initiation of treatment, reaching the maximum magnitude (263 vs 41) at the fourth month. Monthly milk samples showed elevated selenium concentrations (P less than .01, April through August; P less than .05 through September). Intraruminal, selenium soluble-glass bolus administration to gestating cows was highly effective in raising the selenium status of their progeny. Although the control calves were in low-selenium status, no acute cases of nutritional muscular dystrophy were observed during this experiment.

Administration, Oral↗

PubMed1987

Prepartum supplementation of selenium and vitamin E to dairy cows: assessment of selenium status and reproductive performance.

Incidence of retained placenta in dairy cows was evaluated in 627 parturitions. The herd was divided prepartum into three groups: 1) control, no treatment (n = 217 cows); 2) cows injected intramuscularly (n = 190) 21 to 10 d prior parturition with 45 mg Se and 2040 IU of vitamin E; and 3) cows intraruminally administered (n = 220) with two 30-g pellets containing 10% elemental selenium 2 mo prior to expected calving. Incidence of retained placenta (22.1%) was not reduced by Se in combination with vitamin E injection or intraruminal Se pellet nor were other measures of reproduction improved for cows fed a prepartum diet adequate in Se. At parturition the blood plasma Se concentrations were higher in treated postpartum with Se than in untreated cows. No difference in blood plasma Se was observed at parturition between cows with or without placenta retention. Cows dosed intraruminally with Se had a significant increase in milk Se, but this was too small to be a danger to human health. The present results on placenta retention suggest that this disorder is not a Se responsive disease in the dairy cow.

Animals↗

PubMed1987

Effect of excess iron in milk replacer on calf performance.

Milk replacers containing 100, 500, 1000, 2000, or 5000 ppm iron were fed to 3-d-old calves for 6 wk to estimate the lowest amount of dietary iron (added as ferrous sulfate) that would reduce calf performance. Calves tolerated all iron treatments except 5000 ppm. At this intake calves showed reduced weight gains, DM intake, feed efficiency, and digestibility of DM and protein. There were no other signs of iron toxicity and no gross abnormalities were found on postmortem examination. Percent of dietary iron in feces increased with higher dietary iron and ranged from 65 to 84%. Elevated iron intakes caused relatively small increases in iron concentration of blood plasma, bile, kidney, heart, and muscle but marked increased in spleen and liver iron, particularly in liver for the 2000 and 5000 ppm treatments. At 100 ppm iron intake, nonheme iron in liver, spleen, and kidney was composed of similar proportions of ferritin and hemosiderin, but at 5000 ppm iron intake, hemosiderin predominated in these tissues. Thus, the preruminant calf tolerated between 2000 and 5000 ppm iron in milk replacer. At toxic iron intake, calf performance and feed efficiency were reduced; there was a characteristic change to higher liver than spleen iron; and hemosiderin became the predominant iron storage compound in both tissues.

Animal Feed↗

PubMed1987

Vitamin E levels in sheep tissues at various times after a single oral administration of d-alpha-tocopherol acetate.

Five groups, each of 5 sheep of 40-45 kg body weight were used. One group acted as control (killed at 0 time, no vitamin E dose) while the other four groups were given a single oral dose of d-alpha-tocopherol acetate (100 mg/kg body weight) and killed 24, 48, 72 and 240 h after dosing. Samples of adrenal, adipose, heart, liver, kidney, lung, muscle, pancreas and spleen were taken from all 25 sheep and were analyzed for their vitamin E content. In the control sheep the tocopherol concentration in some tissues such as pancreas and adrenal were substantially higher than in the other tissues. Muscle and adipose tissue contained the lowest tocopherol concentrations among the various tissues. Tissues responded differently to the vitamin E dosing. Liver was characterized by a rapid accumulation of alpha-tocopherol at 24 h followed by a progressive loss. In the adrenal and lung the peak occurred 48 h after vitamin E loading. The variable pattern in tocopherol concentrations in the various sheep tissues following vitamin E dosing was considered a reflection of their different metabolic activities.

Adipose Tissue↗

PubMed1986

Tolerance of the preruminant calf for selenium in milk replacer.

Calves were fed skim milk powder-based milk replacer containing either .2, 1, 3, 5, or 10 ppm selenium (added as sodium selenate) in the dry matter from 3 to 45 d of age to estimate the lowest amount of dietary selenium that would reduce calf performance and feed utilization. Only at the highest selenium (10 ppm) did calves show reduced average daily gain and feed efficiency and lower blood packed cell volume. Apparent digestibility of dry matter, nitrogen, and lipid, and plasma creatine phosphokinase activity were not affected by any of the selenium intakes. In general, selenium in blood, bile, duodenal mucosa, liver, kidney, and muscle reflected selenium intakes with liver and kidney reaching the highest selenium concentrations. Postmortem examinations of calves revealed no gross abnormalities for any of the selenium treatments. The preruminant calf is very tolerant of high inorganic selenium concentrations in skim milk powder-based milk replacer.

Animal Feed↗

PubMed1986

Interrelationships among liposoluble vitamins in ruminants.

Plasma concentrations of vitamins A and E were examined in sheep, and a transitory decrease was observed after a single massive dose of vitamin D3 (5 X 10(6) IU) was administered orally or parenterally. Administration of a large dose of vitamin E to sheep decreased plasma retinol concentrations within 72 hours, but thereafter, the plasma retinol concentrations returned to near baseline values. Oral administration of a single pharmacologic dose of dl-alpha-tocopherol (5 g) to sheep caused a slow increase of this vitamin in the blood plasma. In cattle, a single IM administration of 3 liposoluble vitamins (A, D3, and E) at acceptable concentrations had no detectable influence on plasma alpha-tocopherol concentrations with the sampling intervals used. Plasma concentrations of alpha-tocopherol in these cattle showed a marked seasonal pattern; the concentrations increased from January to a peak in July, with a subsequent decrease in the fall. Also reported are estimates of inter- and intraindividual variation in plasma liposoluble vitamin concentrations.

Administration, Oral↗

PubMed1986

Vitamin E response in sheep to various modes of administration.

Specific activity of various tissues was determined in sheep administered with a single dose of D-alpha-(5-Me-3H)-Tocopherol (200 mu Ci) given by one of four routes: intravenous, oral (capsules), intraruminal or intramuscular. The animals were killed at different time intervals, 96 h after intravenous and oral administration, 168 h after intraruminal administration and 216 h after intramuscular administration. Specific activity in the tissues of the intravenously dosed sheep was much higher than in the corresponding tissues of the other groups. In the intravenous group, the highest specific activity was recorded in lung and liver. In the intramuscular group liver had the highest specific activity. No difference in specific activity was recorded among the tissues of the per os groups.

Administration, Oral↗

PubMed1986

Determination of 25-hydroxyvitamin D3 in sheep tissues by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method is described for the determination of 25-hydroxyvitamin D3 (25-OH-D3) in sheep tissue. The procedure involved saponification followed by chromatography on Sephadex LH-20 in order to remove extraneous material. Quantitation of 25-OH-D3 in tissue samples containing as little as 2 ng/g, was achieved by HPLC and ultraviolet detection at 254 nm in HPLC system.

Animals↗

PubMed1986

Mineral and amino acid composition of beef cattle hooves.

Twenty-three Hereford X Shorthorn cattle were used to evaluate the effects of seasonal and dietary changes on the mineral composition (Ca, Mg, Cu, Zn, and S) of hooves. A seasonal pattern was found in the Ca, Mg, and Zn composition of hooves in the 12 cattle evaluated in 1982 and in the 11 cattle evaluated in 1983, with the concentrations of 3 minerals decreasing in winter when dietary change did not occur. Copper concentrations significantly decreased during the 1st year (1982) and had a tendency to decrease during the 2nd year. During the 1983 pasturing season, when effects of seasonal vs dietary change could not be distinguishable, hoof concentrations of Ca and Mg decreased, whereas the inverse trend was observed for Cu and Zn. Seasonal patterns for hoof concentrations of S were not found. Results of mineral analysis of hooves indicated strong correlations between calcium and the other minerals (except S), and between Zn and Cu. Amino acid analyses of hooves of the 11 cattle in 1983 indicated differences in their composition related to dietary changes (winter feeding vs pasture) or to management.

Amino Acids↗

PubMed1985

Intraruminal selenium pellet for control of nutritional muscular dystrophy in cattle.

Administration of an intraruminal selenium pellet to a herd of pregnant crossbred cows was evaluated for controlling nutritional muscular dystrophy in an area of northern Ontario with numerous losses of calves. Cows were winter-fed grass silage. Each spring cows and calves went to pasture. A single dose of intraruminal selenium pellet was given to 80 cows during last 3 mo of pregnancy the 1st yr only while the remaining 80 were controls. During 3 consecutive years, efficacy of intraruminal selenium pellet was evaluated by selenium status of recipient cows and their offspring as well by the incidence of nutritional muscular dystrophy. Selenium in plasma, as well as glutathione peroxidase in whole blood, in the cows administered intraruminal selenium pellet, were higher than in the deficient controls. Ten months after intraruminal selenium pellet treatment, selenium in tissues was higher in treated than in untreated cows but within normal ranges. Before cows were turned out to pasture the 1st yr, milk selenium of intraruminal selenium pellet cows were higher than controls. This technique of selenium dosing was effective in raising the selenium status of the progeny. There was no evidence of nutritional muscular dystrophy in calves from selenium-dosed cows, while 15 calves born of the untreated cows showed clinical symptoms of nutritional muscular dystrophy.

Animals↗

PubMed1985

Mammary transfer of vitamin D3 in the rabbit doe.

Mammary transfer of vitamin D3 from a single intravenous injection containing 100 000 IU vitamin D3 in ethanol, was studied in lactating rabbit does. Significant amounts of the injected vitamin D3 appeared in the milk of does. The highest concentration was observed in the first milk sampling (24 h after administration) which was followed by a decreasing pattern in the five postinjection days. Vitamin D3 concentration in the neonate tissues were smaller than in their dams. In the maternal tissue the highest concentration occurred in the liver, whereas muscle had the lowest value. Among the various neonatal tissues liver contained the highest amounts although in the other tissues appreciable amounts of vitamin D3 were recovered.

Animals↗

PubMed1985

Plasma vitamin D3 response in cattle and sheep exposed to ultraviolet radiation.

Plasma levels of vitamin D3 were determined in a group of 10 cows housed indoors and exposed during the winter to ultraviolet irradiation (UVR). Exposure to UVR was associated with marked rises in plasma vitamin D3 concentrations. The pattern and magnitude of the plasma vitamin D3 response to UVR exposure in sheep raised in total confinement was also investigated. Exposure to sun lamps produced a significant increase in sheep plasma vitamin D3 concentrations. There was no significant difference in the plasma levels of vitamin D3 due to length of time of exposure to UVR.

Animals↗

PubMed1984

Fate of tritium-labeled vitamin D3 and 25-hydroxyvitamin D3 in rabbit does and their pups.

Mammary transfer of label from intraperitoneally injected 50 microCi [1 alpha, 2 alpha(n)-hydrogen-3] cholecalciferol, and 50 microCi (26,27-methyl-hydrogen-3)cholecalciferol was studied in nursing rabbits. Does were injected at 3 days postpartum with one of the two labeled compounds. Pups were killed at either 1, 2, 3, 4, or 5 days after dosing of the does, and does were killed after 5 days. Concentrations of radioactivity were greater in tissues of does dosed with tritiated vitamin D3 than in tissues of those dosed with tritiated 25-hydroxyvitamin D3. Concentrations of radioactivity were greater in maternal tissues than in tissues of pups. On the 5th day following administration of tritiated vitamin D3 or 25-hydroxyvitamin D3, the major portion of the radioactivity in does plasma and liver was associated with tritiated 25-hydroxyvitamin D3. In pups from the tritiated vitamin D3 group, the concentration of plasma radioactivity associated with 25-hydroxyvitamin D3 (isolated by high pressure liquid chromatography) increased significantly with time, reaching 85% of the total vitamin D and metabolite radioactivity in the pups at the 5th day. Over 90% of the total recovered plasma radioactivity of pups of the tritiated 25-hydroxyvitamin D3 group was associated with the 25-hydroxyvitamin D3. Much more radioactivity was secreted in the milk of tritiated 25-hydroxyvitamin D3 dosed does than in milk of does dosed with tritiated vitamin D3.

Animals↗

PubMed1984

Zinc in mammalian sperm: a review.

The relationship of zinc to morphologic, physiologic, and metabolic functions in the male reproductive system are summarized, and gaps in current understanding are pointed out. Semen and its constituents generally contain high zinc, although concentrations vary among animals and species; the relationships between zinc and fertility of semen is unclear. During zinc deficiency, retarded development of testicular growth involved marked atrophy of tubular epithelium and reduced deoxyribonucleic acid, ribonucleic acid, and protein, as well as reduced zinc contents of testis, epididymis, and dorsolateral prostate. Functions of zinc in hormone interrelationships are little understood, but zinc deficiency decreases output of pituitary gonadotrophins and androgen production, and zinc turnover involves testosterone as well as pituitary hormones. Metabolic regulation of sperm appears to be mediated through zinc as a regulator of enzyme activity in the semen. Within spermatozoa, zinc is closely associated with sulfhydryl groups and disulfide linkages and is concentrated in the tail. Control of motility of sperm by zinc apparently involves control of energy utilization through adenosine triphosphate systems involved in contraction and through regulation of phospholipid energy reserves. The many roles for zinc in the male reproductive system are extremely complex and scarcely understood. The importance of zinc contents of commonly utilized feedstuffs in relation to reproductive capabilities of the mammalian sperm remain unclear, although zinc deficiency in relation to male reproduction may be much more widespread than is recognized commonly.

Animals↗