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Biomedical subjects

W L Hurley

Publications and source records attributed to W L Hurley.

At least 19 recordsLinked to original sources
PubMed1992

Heparin-binding properties of lactoferrin and lysozyme.

1. Binding of biotin-heparin to immobilized lactoferrin and lysozyme was optimum at pH 6.0, 100 mM NaCl. Complex interactions between NaCl and CaCl2 concentrations were observed for heparin binding to both proteins. 2. The metal ions Cu2+, Zn2+, Fe2+ and Fe3+ inhibited heparin binding, with half-maximal inhibition of binding to lactoferrin occurring between 600 microM and 1 mM and for lysozyme between 500 and 800 microM. 3. Binding of biotin-heparin to both proteins was inhibited to varying degrees by heparin, heparan sulfate, chondroitin sulfate A, dextran sulfate and DNA.

Anions↗
PubMed1991

Effect of relaxin on mammary development in ovariectomized pregnant gilts.

The role of relaxin in mammary development was studied between days 80-110 of pregnancy in ovariectomized gilts given progesterone to maintain pregnancy. To obtain an objective measurement of lobulo-alveolar (parenchymal) composition, mammary glands were cut in cross-section through the teat, and the area of parenchymal tissue on the exposed face of the gland was determined. Ovariectomy on day 80 or 100 followed by progesterone replacement therapy resulted in a dramatic reduction in the rate of growth of mammary parenchymal cross-section area on days 100 and 110 of gestation, respectively, compared to that in controls. In contrast, progesterone plus relaxin therapy, with highly purified porcine relaxin, restored the mammary parenchymal cross-section area to control values in ovariectomized gilts. Morphometric analysis of mammary tissue on day 110 of pregnancy indicated that both the absence of relaxin after ovariectomy and replacement therapy with porcine relaxin in ovariectomized gilts had little if any effect on the percentages of the lumen, stroma, or epithelial that comprised the mammary parenchyma. It is concluded that relaxin has a stimulatory effect on the growth of mammary parenchymal tissue during late gestation in the pig.

Animals↗
PubMed1989

Purification and characterization of bovine lactoferrin from secretions of the involuting mammary gland: identification of multiple molecular weight forms.

1. Lactoferrin was isolated from bovine mammary secretions collected during the nonlactating period. 2. A method utilizing heparin-agarose affinity chromatography was more efficient for purifying lactoferrin than a method including gel filtration, ion exchange chromatography and a second gel filtration. 3. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that the purified lactoferrin was composed of two protein bands of apparent mol. wt. of 83,000 and 87,000. 4. Digestion with endoglycosidase H resolved the lactoferrin into two lower mol. wt. bands of 78,000 and 81,000. 5. The biochemical differences between the forms of lactoferrin are not exclusively due to differences in endoglycosidase H-sensitive oligosaccharide composition.

Amino Acid Sequence↗
PubMed1989

Characterization of the gene corresponding to bovine placental prolactin-related cDNA I: evolutionary implications.

We have previously characterized a family of transcripts, isolated from bovine placental tissue, that are related to prolactin (PRL) and are distinct from placental lactogen (PL). Here we describe a PRL-related gene that corresponds to one of these placental transcripts, bPRC-I. Restriction endonuclease mapping and sequence analysis of this gene reveal that it is distributed among five exons spanning approximately 9.2 kb. The site of transcription initiation was determined and repetitive sequences were localized in the first two introns. The nucleotide sequence of the coding region is 64% homologous to the bPRL gene and 44% homologous to the bovine growth hormone (bGH) gene. The 5'-flanking region shows no detectable homology to that of bPRL or bGH. Genomic Southern blot analysis indicates that this gene is a member of a family of PRL-related genes.

Amino Acid Sequence↗
PubMed1989

Enzyme-linked immunosorbent assays of bovine lactoferrin and a 39-kilodalton protein found in mammary secretions during involution.

Enzyme-linked immunosorbent assays were developed for two proteins found in mammary secretions during the non-lactating period: lactoferrin and a 39-kdal protein. Minimum detectable concentrations were .12 ng/ml for lactoferrin and .0037 ng/ml for the 39-kdal protein. Standard curves were linear in the ranges of .4 to 100 ng/ml for lactoferrin and 2.4 to 30 ng/ml for the 39-kdal protein. The immunoassays were used to measure concentrations of the proteins in mammary secretions during involution. From the last day of milking to d 30 of involution, mean concentrations of lactoferrin and the 39-kdal protein increased from .82 +/- .35 to 78.5 +/- 12.43 mg/ml and from 11.8 +/- 3.8 to 84.4 +/- 21.1 micrograms/ml, respectively. The immunoassays described will be valuable for further studies on the synthesis and secretion of these proteins during mammary involution.

Animals↗
PubMed1989

Recent developments in the roles of vitamins and minerals in reproduction.

Vitamins and minerals affect reproductive function. Vitamin A deficiency has long been known to affect reproductive function in cattle. More recently, a role has been proposed for the vitamin A percursor, beta-carotene, in reproductive efficiency. Dietary supplementation with vitamin E and selenium may reduce the incidence of retained placenta, but these nutrients may also affect reproductive function in other ways. Calcium and phosphorus deficiencies affect reproduction in cattle, and vitamin D may directly affect reproductive function in addition to its role in calcium and phosphorus metabolism. Dietary manipulation of a number of other vitamins and minerals also influences reproductive function. However, the specific roles of nutrients in reproductive tissues are not well-defined in dairy cattle, and nutrient requirements for optimal reproductive efficiency in modern dairy cattle deserve careful reevaluation. This review provides a background of the effect of vitamins and minerals on reproduction and it attempts to provide a basis for further investigation of specific mechanisms by which reproductive function is affected. The interface between nutritional science and reproductive physiology provides considerable potential for optimizing reproductive efficiency in dairy cattle.

Animals↗
PubMed1989

Mammary gland function during involution.

The process of mammary gland involution occurs during the transition from a lactating to a nonlactating state. This transition phase begins after cessation of milk removal and results in changes in mammary secretion composition. Secretion volume declines during involution, as does the concentration of most milk-specific components. Lactoferrin, hydrolytic enzymes, immunoglobulins, and serum-derived components increase in concentration in the secretions during involution. Changes in mammary secretion composition may reflect changes in function of alveolar epithelial cells and have implications for the disease resistance of the gland. Histological and ultrastructural changes occurring in the gland are consistent with a decline in secretion of milk components from epithelial cells. Autophagocytic mechanisms may be involved in this decline in the lactation function. Ultrastructurally, there is little evidence for an extensive loss of epithelia in the bovine mammary gland during involution. Completion of the functional changes occurring in the gland during the process of involution may be required for the gland to redevelop fully for maximal milk yield in the subsequent lactation. Cellular mechanisms involved in mammary involution and relationships between the processes of involution and redevelopment should be areas of particular interest in the mammary function of dairy cattle.

Animals↗
PubMed1988

Isolation and characterization of a novel 39 kilodalton whey protein from bovine mammary secretions collected during the nonlactating period.

A 39 kilodalton glycoprotein has been isolated from bovine mammary secretions by heparin-agarose affinity chromatography and gel filtration. It is a minor whey protein in mammary secretions collected during the nonlactating period, but is clearly detectable by affinity chromatographic and immunoblotting techniques. It is not detectable by these techniques in milk or colostrum. This protein is not immunologically related to milk proteins, serum proteins or cytoskeletal proteins. The N-terminal amino acid sequence (36 amino acids) is not similar to other known proteins. Isolating this novel 39 kilodalton protein provides a specific marker for mammary function during the nonlactating period.

Acetylglucosaminidase↗
PubMed1988

Immunohistological localization of IgG1, IgA and secretory component in the bovine mammary gland during involution.

Immunoperoxidase methods were used to localize secretory component, immunoglobulin A and immunoglobulin G1 in mammary tissue from dairy cows. In lactating tissue, immunostaining for immunoglobulin A and secretory component was observed primarily in the luminal contents of alveoli. By day 2 of involution, alveolar epithelial cells stained for both immunoglobulin A and secretory component. Staining of alveolar epithelial cells for immunoglobulin A and secretory component continued throughout the period of mammary involution. No staining for secretory component was observed in the interalveolar stromal area. Immunoglobulin G1 immunostaining was localized primarily in the interalveolar areas in lactating tissue, but was localized at the apical and basolateral surface of alveolar cells on day 2 of involution. In contrast to immunoglobulin A, immunoglobulin G1 staining of epithelial cells did not persist and was primarily in the interalveolar areas by day 4. These results suggest that an increased localization of immunoglobulin G1 in bovine mammary epithelial cells may occur transiently in early involution, while an increase in immunoglobulin A and secretory component localization in epithelial cells persists throughout involution.

Animals↗
PubMed1988

Total and differential cell counts and N-acetyl-beta-D-glucosaminidase activity in sow milk during lactation.

Colostrum and milk collected from 11 sows throughout lactation were used to estimate total and differential cell counts and N-acetyl-beta-D-glucosaminidase activity (NAGase). The mean log10 cell counts did not change significantly through the four weeks of lactation, ranging between 250,000 and 750,000 cells/ml. Polymorphonuclear neutrophils (PMN) decreased from about 56% of total leukocytes at day 1 (colostrum) to 12-14% at day 14 and day 21. Macrophages were 35% at day 1 and were the predominant cell type throughout the remainder of lactation, peaking at 77-80% at day 14 and 21. The PMN were again increased on day 28 (44% PMN vs 52% macrophage). The mean lymphocyte proportions ranged between 7.0 and 11.3% during the first two weeks of lactation and were decreased to 4.6-5.6% in the second two weeks of lactation. The activity of NAGase declined 9.5 fold (p less than 0.0001) between day 1 and day 14 with the greatest decline between day 1 and day 3. The activity of NAGase remained constant through the last two weeks of lactation. NAGase activity was significantly correlated with log10 of cell counts in sow milk (r = 0.42).

Acetylglucosaminidase↗
PubMed1988

The effect of immunization against somatostatin on growth and concentration of somatotropin in plasma of Holstein calves.

Holstein calves were used to investigate the effects of immunization procedures against somatostatin (SRIF) on growth and concentrations of somatotropin in plasma. In Trial 1, eight heifers 37 weeks of age were inoculated with cyclic-SRIF conjugated to human alpha-globulin. Final body weight, average daily gain, and measurements of body size were not significantly different between control and SRIF-immunized calves. Apparent total tract nutrient digestibilities and efficiency of feed utilization also were not significantly different between treatments. Plasma concentrations of somatotropin were increased and plasma concentrations of urea nitrogen were decreased in calves immunized against SRIF compared to controls, but these mean differences were not significant. In Trial 2, eleven bull calves seven weeks of age were inoculated with cyclic-SRIF conjugated to keyhole limpet hemocyanin. Calves immunized against SRIF had larger average daily gains (P less than .06) than did control calves. Body size, efficiency of feed utilization, and concentrations of somatotropin in plasma were not significantly different for SRIF immunized calves and control calves. Urea nitrogen in plasma was lower (P less than .04) for calves immunized against somatostatin than for control calves. Data indicate that Holstein calves can produce auto-antibodies against SRIF; however, additional research will be required before such immunization techniques can be effectively used to improve weight gains in cattle.

Animals↗
PubMed1988

Effects of abomasal or intravenous administration of arginine on milk production, milk composition, and concentrations of somatotropin and insulin in plasma of dairy cows.

Holstein cows just past peak lactation were used in a 3 x 3 Latin square design to determine the effects of arginine infusion on concentrations of somatotropin and insulin in plasma, milk production, and milk composition. Treatments were: 1) control; 2) arginine injection into jugular vein, and 3) arginine infusion into abomasum. Concentrations of arginine and ornithine in plasma were increased by injection of arginine into the jugular vein compared with the control. The concentration of ornithine in plasma was increased shortly after injection of arginine into the jugular vein, and both arginine and ornithine concentrations in plasma decreased rapidly. Abomasal infusion of arginine significantly increased concentrations of arginine, ornithine, and urea in plasma compared with concentrations in the control treatment. Injection of arginine into the jugular vein increased concentrations of somatotropin and insulin in plasma, but the increase did not persist for more than 30 min. A secondary peak in plasma somatotropin concentration occurred approximately 1 h after the initial peak. Arginine infusion into the abomasum did not alter plasma concentrations of either somatotropin or insulin. Dry matter intake, milk production, and milk composition were not affected by treatments. Lack of changes in milk production and milk composition suggest that acute increases in somatotropin with concomitant increases in insulin are not sufficient to stimulate synthesis of milk and milk components by cows during established lactation.

Abomasum↗
PubMed1987

Assays and activities of glycosidic enzymes in bovine peripheral blood leukocytes.

Methods are described for the quantitative measurement of N-acetyl-beta-D-glucosaminidase, alpha-mannosidase and beta-glucuronidase in peripheral blood leukocytes of the bovine. Enzyme kinetics and stability were determined. Activities of the glycosidases in polymorphonuclear leukocytes and mononuclear leukocytes were determined using the optimized assays. Polymorphonuclear leukocytes had greater activities of N-acetyl-beta-D-glucosaminidase and alpha-mannosidase, and similar levels of beta-glucuronidase, when compared to mononuclear leukocytes.

Acetylglucosaminidase↗
PubMed1987

Lysosomal enzymes in bovine mammary leukocytes during the nonlactating period.

Leukocytes from mammary secretions in dairy cows were collected during the nonlactating and postpartum periods. Differential cell counts, viability and activity of peroxidase, N-acetyl-beta-D-glucosaminidase (NAGase, beta-glucuronidase and alpha-mannosidase in cells were determined. Cell viability (trypan blue exclusion) was 75-80% during most of the nonlactating period, but declined to 45-50% by parturition. Polymorphonuclear neutrophils (PMN) predominated during the first week of involution, after which macrophages were the predominant cell type. Peroxidase activity in leukocytes from mammary secretions was high in early involution, probably reflecting the predominant peroxidase-containing PMN. Peroxidase activity declined through the remaining nonlactating and postpartum periods. The activity of NAGase was variable in early involution, then increased to a peak during the mid-nonlactating period, before declining prior to parturition. Activity of beta-glucuronidase generally was unchanged during the nonlactating period, although NAGase and beta-glucuronidase activities were significantly and positively correlated throughout the period studied. Activity of alpha-mannosidase changed in a manner similar to peroxidase activity.

Acetylglucosaminidase↗
PubMed1987

Apolipoprotein composition of bovine lipoproteins isolated by gel filtration chromatography.

1. Bovine lipoproteins were isolated from plasma by gel filtration and apolipoprotein composition determined by SDS-polyacrylamide gel electrophoresis. 2. Bovine triglyceride-rich lipoproteins contained a novel low mol. wt protein Mr = 22,000 and low mol. wt proteins that may be analogous to non-ruminant apolipoproteins A-I, A-IV, and E. 3. Apolipoprotein C appeared to be a minor constituent of bovine triglyceride-rich lipoproteins. 4. Triglyceride-rich lipoproteins contained two high mol. wt proteins of approx. Mr = 220,000 and 290,000. 5. The predominant bovine low density lipoprotein apolipoprotein was approx. Mr = 290,000, however, greater then 25 proteins were often observed between Mr = 110,000 and 370,000. 6. Bovine high density lipoprotein contained proteins analogous to apolipoprotein A-I and C apolipoproteins. 7. Differences in apolipoprotein profiles between non-lactating and lactating cows were not apparent.

Animals↗
PubMed1987

Molecular cloning and nucleotide sequence of a bovine alpha-lactalbumin cDNA.

A cDNA clone for the bovine milk protein, alpha-lactalbumin (alpha LA), has been identified using a rat cDNA probe. The bovine cDNA clone is 703 nucleotides (nt) long, contains 8 nt of 5'-untranslated sequence and 269 nt of 3'-untranslated sequence. When compared with previously reported sequences, the bovine alpha LA mRNA sequence has 74% similarity with rat alpha LA mRNA, 79% similarity with human mRNA and 74% similarity with guinea pig mRNA.

Amino Acid Sequence↗
PubMed1987

Molecular cloning of a prolactin-related mRNA expressed in bovine placenta.

Bovine (Bos taurus) prolactin-related cDNA I (bPRC-I), distinct from the isolated bovine placental lactogen, was derived from bovine fetal placental mRNA by molecular cloning. The nucleotide sequence is 63% homologous to bovine prolactin cDNA and only 45% to bovine growth hormone. The region of bPRC-I corresponding to the 5' portion of the signal peptide and 5' untranslated region of bovine prolactin mRNA is markedly different from prolactin. The predicted protein is 39% homologous to bovine prolactin and about 30% to the related placental hormones in rodents. This identification of a prolactin-related gene in the cow in addition to those reported in rodents suggests that multiple prolactin-related genes expressed in the placenta may be a general phenomenon in nonprimates. The role of these related hormones during gestation remains to be investigated.

Amino Acid Sequence↗