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Biomedical subjects

D G Pugh

Publications and source records attributed to D G Pugh.

12 recordsLinked to original sources

Septic metritis secondary to torsion of a pedunculated uterine fibroleiomyoma in a filly.

A 2-year-old Arabian filly was referred for evaluation of a serosanguineous vaginal discharge. Palpation per rectum revealed a large, fluid-filled uterus and a uterine mass. The filly developed septic metritis and secondary laminitis as a result of torsion and necrosis of a pedunculated uterine mass. Ovariohysterectomy was performed. The entire cervix was removed with the uterus. Gross examination of the excised uterus revealed 3 intraluminal masses. Histologic evaluation identified the tumors as fibroleiomyoma. The filly recovered completely, and there was no recurrence of the tumor.

Animals

Characterization of the 5'-flanking region of the human and rat Na,K-ATPase alpha 3 gene.

Genomic clones containing the 5'-flanking region and exon 1 of the human and rat Na,K-ATPase alpha 3 isoform gene have been isolated and characterized. The nucleotide sequences of 1.6 kb of the rat gene and 2.8 kb of the human gene in the 5'-flanking region were determined. Mapping of transcription initiation sites by primer extension and S1 nuclease protection analyses indicates that transcription is initiated in the same region in both genes although the rat gene has a greater number of initiation sites. Neither gene has a canonical TATA box, having instead a ATAT sequence preceding the transcription initiation sites. There is a perfect CCAAT sequence, in the reverse orientation, approximately 30 bp upstream of the potential TATA box in both genes. We have identified potential binding sites for transcription factors Sp-1, AP-1, AP-2, and AP-4, as well as for glucocorticoid and thyroid hormone receptors in the 5'-flanking regions. These are conserved in both human and rat alpha 3 isoform genes.

Animals

The human Na, K-ATPase alpha 1 gene: characterization of the 5'-flanking region and identification of a restriction fragment length polymorphism.

We have determined the sequence of the 5'-flanking region and first three exons of the human Na,K-ATPase alpha 1 gene, ATP1A1. Primer extension and S1 nuclease protection analyses of RNA from human kidney, brain, and skeletal muscle indicate that transcription initiates 273 nucleotides upstream of the translation start site. The promoter region contains a potential TATA box at position -27 relative to the transcription initiation site; however, no CCAAT sequence is observed. The 5'-untranslated and 5'-flanking regions are G + C rich. Five sequence elements exhibiting similarity to binding sites for the transcription factor Sp1 are located within the 5'-flanking region. This region also contains potential binding sites for the transcription factors AP-1, AP-2, AP-3, and NF-1, as well as a site which exhibits perfect identity to an 8-bp sequence element important for calcium induction. A comparison of the 5'-flanking region of the alpha 1 and alpha 2 genes reveals differences in potential transcription factor and hormone receptor binding sites which may be important in mediating the tissue- and developmental stage-specific expression of these genes. We have also identified an intragenic DNA probe which detects a restriction fragment length polymorphism at the alpha 1 locus. This marker should facilitate genetic linkage studies designed to evaluate the role of the sodium pump in human disease.

Base Sequence

Characterization of the human Na,K-ATPase alpha 2 gene and identification of intragenic restriction fragment length polymorphisms.

We have determined the structure of the gene that encodes the alpha 2 isoform of the human Na,K-ATPase. The gene contains 23 exons and spans approximately 25 kilobases. The amino acid sequence of the human alpha 2 isoform deduced from the genomic sequence exhibits 99% identity to the rat alpha 2 isoform. One of the nine amino acid differences between the human and rat sequences occurs at an amino acid position which is known to be involved in species differences in sensitivity of the alpha 1 isoform to cardiac glycosides. Approximately 1500 base pairs of sequence flanking the 5' end of the alpha 2 gene have been determined. This region contains numerous potential AP-1, AP-2, and NF-1-binding sites, a potential Sp1 recognition site, and several sequences that are similar to the glucocorticoid receptor-binding site. The transcription start site was mapped by primer extension and S1 nuclease protection analyses of RNA from human brain, skeletal muscle, and heart. Multiple transcription initiation sites are clustered between residues -104 to -99 relative to the translation initiation codon. A potential TATA box is located 29 base pairs upstream of the first transcription initiation site. Immediately 5' to the apparent TATA box is a 35-base pair polypurine.polypyrimidine tract containing an imperfect mirror repeat which resembles sequences that form triple-stranded structures. Two intragenic DNA probes which detect restriction fragment length polymorphisms associated with the alpha 2 gene have been identified. These probes will be useful in genetic linkage analyses designed to define the possible role of the Na,K-ATPase in certain hereditary disorders.

Amino Acid Sequence

Influence of a wide range of calcium intakes on tissue distribution of macroelements and microelements in dairy calves.

Sixteen intact male Holstein calves averaging 86 kg and 63 d of age were assigned randomly to four treatment groups. The four treatment diets contained .17, .67, 1.31, and 2.35% Ca on an as-fed basis. The resulting Ca:P ratios with P held constant at about .34% were .47:1, 1.92:1, 3.83:1, and 7.20:1. Calves were fed diets at 3% of their body weights for 4 wk. Magnesium in the bone ash and serum was lowered by the 2.35% Ca treatment. Serum inorganic P was also reduced by the highest Ca diet during the last 2 wk of the experiment. Liver had the highest concentration of Zn in calves fed .67% Ca, and the muscle from calves fed 1.31% Ca diet had the lowest amount of Zn. Copper was reduced in pancreas for 1.31% Ca diet, but Ca was highest in the muscle and heart at the .67% Ca treatment. Weight gains and feed efficiencies were not affected by Ca. Fecal pH was different among treatments and increased as Ca intake increased. Young growing dairy calves can adapt to a wide range of Ca intakes and Ca:P ratios and maintain a moderate growth rate for 4 wk. It appears that excessive dietary Ca may affect concentrations of Zn, Fe, Cu, and Mn in some body tissues, but the magnitude of the effect is relatively small.

Animals

Influence of high dietary lead on selenium metabolism in dairy calves.

Metabolism of orally dosed 75Se was studied in 10 intact male Holstein calves that were fed ad libitum a control diet containing no added Pb or supplemented with 1000 ppm Pb as PbSO4 for 4 wk. Lead-supplemented calves did not exhibit any clinical signs of Pb toxicity. Voluntary feed intake was reduced by 9.5% and average daily gain by 23%. Lead content of rib, liver, and kidney increased. Serum glutamic oxaloacetate transaminase activity was increased during the last 2 wk of the experiment in calves fed Pb. In calves receiving supplemental Pb, 75Se absorption, blood concentration, and urine concentration were reduced by 26, 21, and 42%, respectively. Tissue 75Se concentrations were significantly lower in kidney, liver, testicle, pancreas, small intestine, heart, spinal cord, and muscle in calves fed Pb. There was a significant negative correlation (r = -.78) between 75Se and stable Pb concentrations in the liver. It is not clear whether the ingestion of subclinical amounts of Pb could affect the absorption and utilization of Se in dairy calves to the extent of Se deficiency when dairy calves are kept in areas known to be low in Se.

Animals

Effects of varying the amounts of dietary calcium on selenium metabolism in dairy calves.

Influence of dietary Ca on Se metabolism was studied with 16 intact male Holstein calves averaging 86 kg. Calves were assigned randomly and fed one of four diets containing, .17, .67, 1.31, and 2.35% Ca at 3% of their body weight for 4 wk. The diets contained .062 ppm Se and .34% P. Four days prior to the end of the experiment, calves were dosed orally with radioactive 75Se. Dietary Ca had no significant effect on 75Se absorption. There was a slight curvilinear relationship between apparent 75Se absorption and dietary Ca intakes. Urinary excretion of 75Se and stable Se tended to decrease with increasing dietary Ca, but differences were not significant. No significant differences were found in concentration of 75Se in several tissues. Kidney and liver had the highest concentration with that in kidney being about four times that of liver. Apparent 75Se absorption was decreased 10 to 6%, respectively, in calves fed extremely low and high amounts of Ca, compared with those receiving the requirement (.67% Ca). These small reductions along with a small R2 suggest that dietary Ca probably is of little practical importance relative to Se metabolism in calves.

Animals

Restraint.

The object of restraint is to limit, restrict, and keep under control the animal's movement while performing different procedures. The author discusses the importance of evaluating the horse and its owner prior to employing any type of restraint, various concepts of restraint, and examples of situations in which restraint may be required.

Animal Communication

Potassium toxicity and acid-base balance from large oral doses of potassium to young calves.

Potassium chloride and sodium chloride were infused into the reticulorumen of male Holstein calves, approximately 6 mo of age and 260 kg, at .29, .58, 1.15, 1.73, 2.31, or 2.88 g potassium per kilogram body weight or 1.35, 2.12, or 2.16 g sodium per kilogram in equal volumes of water. Paired controls were infused with water. Calves were monitored for physiological changes for 6 h at 15, 30, or 60-min intervals. Potassium and total solids of plasma and packed cell volume were increased at potassium doses greater than .29 g of potassium per kilogram body weight within 1 h after dosing. At the higher doses of potassium, sodium content of plasma increased about 1 h after the increase in plasma potassium. Respiration rates within a potassium treatment varied with respect to time after dosing, but generally they increased, and associated variables of carbon dioxide pressure, pH, and bicarbonate in blood were decreased accordingly. Clinical toxicity signs, including excess salivation, muscular tremors of legs, and excitability were observed with potassium doses greater than .58 g of potassium per kilogram body weight. Three of five calves given 1.73 g of potassium per kilogram, three of four calves given 2.31 g of potassium per kilogram, and one calf given 2.88 g of potassium per kilogram body weight died. With a small number of calves, oral sodium infusions increased plasma sodium in proportion to the dose, but plasma potassium remained relatively constant. Sodium infusions of 2.12 and 2.16 g of sodium per kilogram body weight were fatal.

Acid-Base Imbalance

Effects of feeding high magnesium to young dairy calves.

Holstein bull calves were fed 1, 2, and 4% supplemental magnesium as magnesium oxide. The control diet contained .3% magnesium and consisted of ground corn, soybean meal, cottonseed hulls plus mineral, vitamin, and antibiotic supplements. Diarrhea was the most obvious effect of high intake of magnesium. The extent and intensity of the diarrhea was related closely to the dietary magnesium content. High (2 and 4%) magnesium reduced feed consumption and weight gains. Although there were traces of blood in feces, no abnormalities were observed at autopsy. Large tubular sections of mucus were voided in the feces with a greater prevalance among calves fed 2 and 4% supplemental magnesium. Magnesium in plasma rose sharply in response to the increased intake of magnesium. In calves receiving the 4% added magnesium, the plasma values were triple those of controls. When high magnesium was fed, magnesium increased much more in urine than in plasma. Within 1 wk after calves were returned to control diet, magnesium in urine and plasma declined to control.

Animals