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At least 235 records · Page 13Linked to original sources
PubMed1977

Changes in ultrastructure and function of the sheep pigment epithelium and retina induced by sodium iodate. I. The ultrastructure of the normal pigment epithelium of the sheep.

The normal ultrastructure of the sheep pigment epithelial cells is described as a basis for the interpretation of toxic (sodium iodate) effects on these cells dealt with in two following papers. The morphological features of the different cell membranes and cell organelles, particularly the phagosomes and the lipid droplets, are discussed in relation to renewal of the photoreceptor outer segment, pigment epithelial and retinal metabolism, barrier mechanisms and electrical properties.

Animals↗
PubMed1994

Synaptonemal complex analysis of domestic sheep (Ovis aries) with Robertsonian translocations. I. Pachytene karyotype substaging of normal sheep.

Meiotic chromosome pairing behaviour in three normal sheep was surveyed by synaptonemal complex (SC) analysis at the electron microscope level. The SC karyotype of normal rams is composed of a sex pair, three metacentric or submetacentric pairs, and 23 acrocentric autosomal bivalents, with the total autosomal SC length ranging from 309 to 315 mircrons. Five nucleoli are terminally located on the three metacentric, and one large and one small acrocentric autosomal bivalents. XY morphology was used to divide pachytene into five substages. Although pairing abnormalities (mostly SC interactions) were recorded in an average of 16% of the spermatocytes, bivalent-XY association occurred in only 4.7% of the cells.

Animals↗
PubMed1982

Vanadium metabolism in sheep. II. Effect of dietary vanadium on performance, vanadium excretion and bone deposition in sheep.

Sixteen ram lambs were fed 0, 50 or 200 ppm supplemental vanadium daily as NH4VO3 for 90 d and coccygeal vertebrae were sampled at 0, 15, 30, 60 and 90 d after the imposition of dietary treatments. Vertebral vanadium content was elevated (P less than .05) after exposure to 200 ppm added vanadium in the diet of 15 d, but nonsignificant increases occurred thereafter. Increasing dietary vanadium increased bone ash vanadium concentration from .4 to 1.7 and 3.8 ppm in sheep fed 0, 50 and 200 ppm supplemental vanadium, respectively. In a balance study, urinary concentrations of the element also were related directly to dietary intake. A trend toward elevated urine volume with increased intake of vanadium was also observed.

Absorption↗
PubMed1989

Computer modeling of sheep reproduction: II. Accelerated reproduction in sheep.

A computer simulation program was written in SLAM (Simulation Language for Alternative Modeling) to simulate certain biological aspects involved in alternative systems of reproduction in sheep. Four fundamental lambing schemes, once a year, three times in 2 yr, twice a year and continuous schemes, along with modifications of these schemes, are simulated. Parameters of greatest effect in this simulation were the average spread of the estrous season (SA), the measure of asymmetry (SD) and the maximum proportion of ewes exhibiting estrus (MX). It was demonstrated that the greater the SA values (longer estrous seasons and shorter anestrous seasons), the more advantageous it was to breed frequently. The SD and MX parameters influenced to a lesser degree the lambing results obtained from these simulations. The relative merits of certain breeds and locations for out-of-season breeding were studied and evaluated for annual and seasonal fertility.

Algorithms↗
PubMed1978

[Residues of the antifluke preparations, dovenix and acredist, in sheep milk and their effect on the biochemical blood indices of sheep].

The excretion of residual amounts of acedist and dovenix with the milk of sheep that had been treated with these preparations was established on the 24th, resp., up to the 27th day following treatment, though their presence in the milk was found to drop sharply after the third day. The treatment with acedist led to a dependable decrease (P less than 0.05) in the hemoglobin amount, the total protein, and the erythrocyte count, and a dependable increase (P less than 0.05) in the leukocyte count. The intensity of these changes subsided parallel to the decrease in the residual amounts of the preparation in the milk excreted. The treatment with dovenix did not result in any deviations of the indices refered to.

Animals↗
PubMed1985

Phenolsulfonphthalein test in healthy sheep and in sheep with reductions in functional renal mass.

The phenolsulfonphthalein (PSP) plasma clearance and urinary excretion tests were applied to sheep before and after 50% and 75% reductions in functional renal mass. The PSP determinants found most useful as indicators of renal mass reduction were the 15-minute urinary excretion percentage and the 60-minute (PSP60) plasma concentration. Although both of these determinants could be used to detect renal mass reduction, the 15-minute PSP excretion percentage was the more sensitive. The PSP60 value was influenced by factors other than reduced nephron numbers; the contraction of the PSP volume of distribution that occurred after renal mass reduction was one important influencing factor. Overall, the PSP tests more accurately reflected the volume of blood delivered to the kidney than the proximal tubular secretory capacity.

Animals↗
PubMed1975

[Studies on the properties of acid erythrocyte phosphatase in sheep and the isoenzymes of sheep and goat acid erythrocyte phosphatase].

Ovine erythrocytic acid phosphatase showed two peaks of activity at pH 5.0 and 5.7 in acetate buffer with p-nitrophenylphosphate as substrate. The enzyme was only slightly inhibited by fluoride and L-phenylalanine, but high concentrations of urea strongly inhibited it. Activity of the enzyme was greater in goat erythrocytes than in sheep. By means of starch electrophoresis, three isoenzymes belonging to nine types were separated from the ovine enzymes, while three isoenzymes of five types were present in goats. Electrophoresis in polyacrylamide gel was suitable for detecting the rapidly migrating isoenzymes.

Acid Phosphatase↗
PubMed1977

Hemoglobin switching in sheep and goats. Preparation and characterization of complementary DNAs specific for the alpha-, beta-, and gamma-globin messenger RNAs of sheep.

Specific complementary DNAs (cDNAs) for the messenger RNAs coding for sheep alpha-, betaA-, betaB-, betaC-, and gamma-globins were prepared by thermal denaturation of heterologous hybrids (e.g. alphabetaB-cDNA-alphagamma-mRNA) followed by hydroxylapatite chromatography. Each cDNA represented a nearly full-length copy of its globin mRNA complement as determined by electrophoretic analysis in polyacrylamide gels containing 98% formamide. The purity of each cDNA fraction was estimated by hybridization analysis and thermal denaturation. The beta- and gamma-cDNAs contained 5 to 20% contaminating alpha-cDNA while the alpha-cDNA was 25 to 30% contaminated with non-alpha-cDNA. The melting temperatures (Tm) of homologous duplexes between each non-alpha chain cDNA and its mRNA complement ranged from 69.5-71.5 degrees in 50% formamide while alpha-alpha duplexes melted with a Tm of 75-76 degrees. The Tm values of heterologous duplexes formed between each non-alpha-cDNA and the various globin mRNAs (e.g. betaB-cDNA-Hb C mRNA) ranged between 64.5 degrees and 68 degrees and thus were only 1.5-5.0degrees below that of homologous duplexes. These results suggest that the nucleotide sequence divergence among the various non-alpha-mRNAs (or cDNAs) is not greatly different from the minimum predicted from the amino acid sequence differences of the corresponding globins. When annealing reactions were performed above the Tm of the heterologous hybrids (68 degrees), each non-alpha-cDNA hybridized only to its own complementary mRNA. Thus the purified cDNAs provide molecular probes for the quantitation of alpha-, beta-, and gamma-globin-specific nucleotide sequences.

Animals↗
PubMed1977

Sulphur-selenium studies in sheep. I. The effects of varying dietary sulphate and selenomethionine on sulphur, nitrogen and selenium metabolism in sheep.

Sulphur, selenium and nitrogen metabolism were studied in Merino wethers fed for 35-day periods on semipurified diets in which the sulphur content was increased to either 0-07 or 0-20% by the addition of sodium sulphate. At both levels of sulphur, additions of selenium as DL-selenomethionine increased the basal level of selenium (0-02 microgram/g) to 0-06, 0-09 and 0-67 microgram/g. Both levels of dietary sulphur supported positive sulphur balances but a reduction in sulphur intake per se resulted in a significant depression in dry matter digestibility (P less than 0-05), apparent nitrogen digestibility (P less than 0-05), nitrogen balance (P less than 0-01), sulphur balance (P less than 0-05) and plasma sulphate-sulphur (P less than 0-05) and wool (P less than 0-01) selenium levels. Selenium balance was not affected by differences in sulphate-sulphur intake. Selenium balances (P less than 0-001), plus the selenium levels in plasma (P less than 0-001), and wool (P less than 0-001) were significantly different at the different levels of selenium supplementation. A positive selenium balance was achieved when the selenium intake was approximately 37 microgram/day, regardless of sulphur treatment. The validity of using plasma and/or wool selenium levels as indices of the selenium status of sheep is questioned.

Animals↗
PubMed1983

Vitamin E status of cattle and sheep. 2: Survey of liver from clinically normal cattle and sheep for alpha-tocopherol.

Analysis of liver from clinically normal animals showed a mean alpha-tocopherol level of 20 mg/kg for cattle and 6 mg/kg for sheep. The corresponding normal values (mean +/- 2 S.D.) were 9 to 44 mg/kg and 1.8 to 20 mg/kg. The usefulness and assessment of tocopherol analyses on liver and serum samples are discussed in the light of these normal values and routine diagnostic submissions.

Journal Article↗
PubMed1976

Inhibitory effect of sheep erythrocyte fragments on rosette formation of human T lymphocytes with sheep red blood cells.

The effect of sheep red blood cells (SRBC) fragments on rosette formation of human peripheral T lymphocytes with SRBC was evaluated on the active and total T-rosette tests. The rosetting capacity of active rosette-forming cells was selectively and nearly completely inhibited by the pretreatment of lymphocytes with SRBC fragments. The decrease in total rosettes by blocking with SRBC fragments was almost parallel to that of active rosettes. SRBC fragments had no inhibitory effect on the rosetting capacity of a lymphocyte population in which active rosette-forming cells were removed by gradient centrifugation. These results suggested that active rosette-forming cells in human T lymphocytes have the receptors of high affinity for SRBC and these receptors readily bind SRBC fragments, resulting in block of rosette formation.

Animals↗