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Biomedical subjects

M E White

Publications and source records attributed to M E White.

At least 73 records · Page 4Linked to original sources
PubMed1993

Insulin-like growth-factor binding protein (IGFBP) serum levels and hepatic IGFBP-2 and -3 mRNA expression in diabetic and insulin-treated swine (Sus scrofa).

1. Diabetes had no significant effect on IGFBP-3 message and serum levels however, subsequent insulin treatment caused more than a two-fold increase in both hepatic IGFBP-3 mRNA and serum levels above controls (P < 0.05). 2. The induction of diabetes in pigs significantly increased the steady state levels of IGFBP-2 mRNA in the liver of young swine (P < 0.05). 3. Both liver message and serum IGFBP-2 were reduced to control levels with insulin therapy. 4. We report here that in addition to its affects on IGFBP-2, insulin is involved in the regulation of IGFBP-3 expression.

Animals↗
PubMed1993

Developmental changes in hepatic IGF-2 and IGFBP-2 mRNA levels in intrauterine growth-retarded and control swine.

1. Significantly elevated levels of hepatic IGFBP-2 mRNA were detected in IUGR piglets at 90 days fetally and at birth (P < 0.05). 2. Developmentally, hepatic IGF-2 (P < 0.05) and IGFBP-2 (P < 0.01) mRNA levels were higher fetally and at birth than at 21 and 49 days of age. 3. This study provides new information concerning hepatic expression of IGF-2 and IGFBP-2 in developing swine.

Animals↗
PubMed1993

Molecular analysis of the 18q- syndrome--and correlation with phenotype.

Seven individuals with deletions of the distal long arm of chromosome 18 were evaluated at the clinical, cytogenetic, and molecular levels. The patients had varying degrees of typical clinical findings associated with the 18q- syndrome. Cytogenetic analysis revealed deletions from 18q21.3 or 18q22.2 to qter. Somatic cell hybrids derived from the patients were molecularly characterized using ordered groups of probes isolated from a chromosome 18-specific library. In general, the size of the deletion could be correlated with the severity of the phenotype. Based on the clinical pictures of these seven patients, a preliminary phenotypic map for the clinical features associated with deletions of the distal portion of the long arm has been generated. Furthermore, genes previously localized to 18q21 were mapped relative to the chromosome breakpoints present in these patients.

Abnormalities, Multiple↗
PubMed1992

An outbreak of blue-eared pig disease (porcine reproductive and respiratory syndrome) in four pig herds in Great Britain.

The clinical syndrome of a new disease of pigs in four herds in the Humberside area is described. The first signs of the disease were anorexia, lethargy and pyrexia with up to 60 per cent of the dry sows affected. These signs were followed by an increased incidence of abortions which occurred in up to 3.3 per cent of sows, premature farrowings in up to 20.6 per cent of sows and stillbirths and late mummification which affected up to 26.0 and 18.8 per cent of fetuses, respectively. Mortality in neonatal and pre-weaning pigs reached up to 88 per cent and respiratory disease of high morbidity and low mortality occurred in fattening pigs. There were infertility problems in sows, with an increase in returns to service and a failure to show oestrus after weaning or aborting. The signs of the disease in boars were anorexia and malaise. Cyanosis of the extremities affected up to 2 per cent of the animals. The outbreak lasted 11 weeks in all the herds.

Abortion, Veterinary↗
PubMed1992

Experimental phylogenetics: generation of a known phylogeny.

Although methods of phylogenetic estimation are used routinely in comparative biology, direct tests of these methods are hampered by the lack of known phylogenies. Here a system based on serial propagation of bacteriophage T7 in the presence of a mutagen was used to create the first completely known phylogeny. Restriction-site maps of the terminal lineages were used to infer the evolutionary history of the experimental lines for comparison to the known history and actual ancestors. The five methods used to reconstruct branching pattern all predicted the correct topology but varied in their predictions of branch lengths; one method also predicts ancestral restriction maps and was found to be greater than 98 percent accurate.

Biological Evolution↗
PubMed1992

Insulin-like growth factor-I levels and gene expression in ovine hereditary chondrodysplasia (spider lamb syndrome).

Hereditary Chondrodysplasia or Spider Lamb Syndrome (SLS) is an inherited, semi-lethal, musculo-skeletal disease affecting lambs primarily of Suffolk or Hampshire breeding. Deformities of the limbs and spinal column along with multiple sites of ossification at the anconeal process are diagnostic for the disease. Muscle atrophy is also predominant. We have investigated the relationship between SLS and circulating levels of IGF-I and the IGF-BPs in older (50-80 d of age) animals. Serum IGF-I levels were lower (P less than 0.01) in SLS affected lambs (117 ng/ml) than in phenotypically normal lambs (188 ng/ml) while serum levels of the 32 kDa BP increased (P less than 0.01) 77% in SLS affected lambs as compared to contemporary controls. All other IGF-BPs appeared to be unaffected in this group. Gene expression of IGF-I and -II in the liver and muscle of younger (16-22 d of age) lambs was also measured. There were no differences in IGF-II expression in either muscle or liver between SLS affected and phenotypically normal control lambs. Muscle IGF-I expression also did not differ. However, liver IGF-I expression in SLS affected lambs was nearly double that of control lambs (P less than 0.01). These data suggest that the regulation of IGF-I and the IGF-BPs may be involved in the physical manifestations of this disorder.

3-Hydroxybutyric Acid↗
PubMed1992

Influence of somatotropin on lipid metabolism and IGF gene expression in porcine adipose tissue.

The present study was designed to evaluate the effects of porcine somatotropin (pST) treatment (2 mg/day) and dietary fat (10%) separately and in combination on the metabolic activity of subcutaneous adipose tissue, serum adipogenic activity, and insulin-like growth factor (IGF) gene expression within adipose tissue from growing 5- to 6-mo-old barrows. This study attempted to determine how these factors might contribute to the reported changes in adiposity of treated swine. Biopsies of adipose tissue were collected after 28 days of treatment following anesthesia with thiopental sodium (15 mg/kg iv). Somatotropin inhibited in vitro glucose oxidation and lipogenesis in adipose tissue but did not affect fatty acid esterification. Adipogenic activity of serum was not altered by pST treatment. Subcutaneous adipose tissue contained mRNA for IGF-I and -II, and pST administration increased the abundance of IGF-I mRNA. Dietary fat had no effect on these variables. Thus somatotropin reduces glucose metabolism in porcine subcutaneous adipose tissue. Preadipocyte proliferation and differentiation are not affected by somatotropin through its actions on systemic factors. Dietary fat provides no additional benefit in combination with pST administration to affect accretion of adipose tissue in growing swine.

Adipose Tissue↗
PubMed1992

Intestinal development and fatty acid binding protein activity of newborn pigs fed colostrum or milk.

Newborn pigs (n = 20) were gavage-fed sow's colostrum, defatted colostrum, milk, defatted milk or a 5% lactose solution over 24 h in order to evaluate effects on growth and functional differentiation of small intestine. Colostrum-fed pigs had greater (p less than 0.01) mucosal mass in the proximal half of the small intestine than did the milk- or lactose-fed groups. Total fatty acid binding protein (FABP) activity and FABP activity per mg DNA in proximal intestines of colostrum-fed pigs exceeded that for the lactose group. FABP activities (per g mucosa or mg soluble protein) were greater (p less than 0.01) in the proximal segments of small intestines of pigs fed whole versus the corresponding defatted secretion. These results indicate that the feeding of colostrum specifically augments perinatal intestinal growth and differentiation as manifested by increased cellular hypertrophy and FABP activity. Milk lipid and unidentified factor(s) enriched in colostrum are inducers of intestinal FABP activity.

Animals↗
PubMed1992

Gene expression and secretion of insulin-like growth factor-binding proteins during myoblast differentiation.

Numerous cell types have been reported to secrete insulin-like growth factor-binding proteins (IGFBPs) in vitro. We have observed such IGFBPs in culture medium conditioned by the mouse myoblast cell line C2C12 and have identified IGFBP-2 among the secreted IGFBPs. Since C2C12 cells fuse in culture, these cells were used to examine IGFBP-2 mRNA expression and protein secretion during myogenic differentiation. Cells were harvested at approximately 80% of confluent density. Additional cultures were rinsed, fed differentiation medium, and harvested when approximately 15%, 60%, and 85% differentiated (fused). Northern and dot blot analyses were performed using total cellular RNA and a labeled cDNA specific for rat IGFBP-2. A single mRNA transcript of approximately 1.8 kilobases was observed. The level of expression of IGFBP-2 mRNA was highest in proliferating cells and decreased to 35%, 20%, and less than 10% of initial levels as differentiation progressed. Serum-free medium was conditioned for 24 h at each time point and collected from similar cultures. Three IGFBP species of 32,000, 30,000, and 24,000 mol wt (Mr) were detected in conditioned medium by probing Western blots with [125I]IGF-I (ligand blot analysis). The intensity of the 32,000 Mr band decreased with differentiation. These same blots were probed with an antibody raised against the 34,000 Mr bovine IGFBP-2. This antibody specifically bound to only the 32,000 Mr IGFBP. The level of antibody binding decreased by 50%, 90%, and nearly 100% as differentiation progressed. It, therefore, appears that IGFBP-2 is expressed and secreted in a differentiation-dependent manner by C2C12 myoblasts and may, thus, be involved in the process of myoblast differentiation.

Animals↗
PubMed1992

Risk factors for injuries due to the 1990 earthquake in Luzon, Philippines.

On 16 July 1990, an earthquake measuring 7.7 on the Richter scale struck the island of Luzon, Philippines. A case-control study was carried out to identify the risk factors for earthquake-related injuries and at the same time observations were made on the rescue efforts. Being hit by falling objects was the leading cause of injury (34%). Those injured during the tremor were more likely to have been inside buildings constructed of concrete or mixed materials (odds ratio, 2.6; 95% confidence interval (CI), 1.7-4.1) and to have been on the middle floors of multistorey buildings (odds ratio, 3.4; 95% CI, 2.2-5.5). Leaving a building during the earthquake was a protective behaviour (odds ratio, 0.3; 95% CI, 0.2-0.8). Of the 235 survivors who were trapped and rescued alive from the rubble, 99% were rescued within 48 hours of the impact of the tremor. These findings should prove useful in developing seismic safety codes. People should be taught proper evasive actions to take during earthquakes, and training in basic first aid and methods of rescue should be an integral part of community preparedness programmes.

Case-Control Studies↗
PubMed1991

Multivariate analysis of factors associated with calving interval and calving rate in dairy cows.

We collected data on reproductive events of cows (n = 2116) that included dates of calving, first service, last artificial insemination before pregnancy examination, pregnancy examination, abortion, diagnosis of cystic ovary, and treatment with prostaglandin. We used multivariate analysis to evaluate the relationship between the interval from insemination to pregnancy examination and the length of calving interval, adjusting for other factors affecting the calving interval. The effect of the interval from insemination to pregnancy examination on calving rate was estimated using logistic regression analysis. The calving interval was long for cows with a short interval from artificial insemination to first pregnancy examination, it was at a minimum at 55 d and increased thereafter. Other factors affecting the calving interval were cystic ovaries, prostaglandin treatment, abortion, number of artificial inseminations, and days to first service. The calving rate was low among cows with a short interval to pregnancy examination, reached a maximum at 48 d, and then declined. Other factors affecting the calving rate were abortion, number of artificial inseminations and whether the cow was bred by a clean-up bull.

Journal Article↗
PubMed1991

Functional antagonism between endogenous mouse growth hormone (GH) and a GH analog results in dwarf transgenic mice.

A dwarf transgenic mouse (DTM) line has been established in which mice express relatively high levels of a mutated bovine (b) GH gene. This bGH analog binds to mouse liver membrane preparations with an affinity similar to that of wild-type bGH. The mean growth ratio of these mice is approximately 0.7 relative to that of their nontransgenic littermates. Serum insulin-like growth factor-I (IGF-I) levels of DTM were found to be approximately half those in nontransgenic littermates. Liver GH receptor levels were up-regulated in DTM or wild-type bGH transgenic mice. Pituitary GH levels were negatively correlated with serum IGF-I concentrations. Wild-type bGH transgenic mice contain relatively high serum IGF-I and low pituitary GH levels, whereas DTM possess low serum IGF-I and high pituitary GH levels. The decrease in serum IGF-I resulting from the interaction between the bGH analog, the endogenous mouse GH, and GH receptor(s) apparently leads to a dwarf phenotype. These data suggest that this bGH analog has uncoupled GH ligand-receptor binding from IGF-I production and acts as a functional antagonist to the action of endogenous mGH.

Animals↗
PubMed1991

Effect of weaning at different ages on serum insulin-like growth factor I (IGF-I), IGF binding proteins and serum in vitro mitogenic activity in swine.

We investigated the effects of weaning or fasting of 21- or 35-d-old swine by monitoring serum mitogenic activity, circulating insulin-like growth factor I (IGF-I) and its binding proteins using L6 myoblast bioassays, RIA and ligand blotting techniques. Serum samples were collected from 21- or 35-d-old animals just before and 36 h after weaning or fasting. Sera from 21- and 35-d-old weaned animals were not significantly altered in their ability to promote myoblast proliferation, whereas sera from 21- and 35-d-old fasted animals caused 29 and 21% decreases (P less than .05) compared with preweaning. The mitogenic activity of control serum was inhibited by serum from fasted animals but not by preweaned or weaned sera. Serum IGF-I levels were decreased 65 to 70% (P less than .05) with weaning or fasting at both ages. Unoccupied binding sites on circulating IGF binding proteins in the 155 kDa range decreased 18 to 19% with weaning at both ages and decreased 40% (P less than .05) with fasting at 21 d but only 17% at 35 d. Ligand blotting revealed that the 43 and 39 kDa IGF binding protein bands decreased with weaning and fasting at both ages, whereas the 29-kDa band increased with weaning and fasting. These data indicate that serum IGF-I and specific IGF binding protein bands decrease during weaning or fasting at 21 and 35 d of age. However, serum mitogenic activity did not always follow serum IGF-I levels.

Age Factors↗
PubMed1991

Effect of maternal fasting on fetal and placental lipid metabolism in swine.

This experiment was designed to determine whether mobilizing maternal energy stores by fasting pregnant gilts would promote fetal energy storage by altering placental and fetal lipid metabolism. Pregnant gilts were fed a 15% tallow diet from d 80 to 99 and then fed a basal high-carbohydrate diet (control) or fasted from d 100 to 110 of gestation. Caesarean section was performed on d 110. Fasting caused maternal nonesterified fatty acid (NEFA) levels to increase 7.5-fold, beta-hydroxybutyric acid (beta-HBA) levels to increase 4.8-fold triglyceride (TG) levels to decrease 1.8-fold, and no change in plasma glucose concentration compared with controls. Fasted fetuses had a 1.3-fold increase in NEFA, 1.9-fold decrease in TG, 1.5-fold decrease in glucose, and no change in beta-HBA levels compared with control fetuses. Distribution of NEFA in fetal plasma was different from distribution of NEFA in maternal plasma. Esterification of [14C]-palmitate by maternal placenta and fetal adipose tissue was reduced by fasting, but other parameters of fatty acid metabolism were unaffected. Fasting decreased lipoprotein lipase activity per milligram of protein by 33% in maternal placenta and by 44% in fetal adipose tissue. Glycogen content of fetal liver and skeletal muscle was reduced by fasting pregnant gilts, but there was no detectable effect on percentage of carcass lipid of the fetus. These data suggest that fasting mobilizes maternal fuel stores but that these stores are not effectively used by the placenta or transported to the fetus for storage.

3-Hydroxybutyric Acid↗
PubMed1991

Fatty acid metabolism by the porcine placenta.

Two experiments were performed to determine whether esterification is a major pathway of fatty acid utilization within porcine placenta and to determine what metabolic parameters may limit fatty acid transfer to the fetal pig. Maternal (endometrium) and fetal (chorioallantois) placenta were obtained by Caesarean section at d 110 of gestation in both experiments. Eight gilts were used in the first experiment. Tissue sections were incubated with palmitate at concentrations ranging from .25 to 2.0 mM. Maternal placenta metabolized palmitate at a higher rate than fetal placenta, although fetal placenta was more efficient in esterifying palmitate. Esterification composed the majority of palmitate utilization within fetal and maternal placenta. The second experiment evaluated the effect of dietary lipid on placental fatty acid metabolism and evaluated the ability of placenta to mobilize lipids. Fourteen gilts were divided into two groups of seven and fed a diet containing 15% tallow diet or a diet not supplemented with tallow (control) from d 90 to 110 of gestation. Dietary lipid had no detectable effects on lipoprotein lipase activity, [14C]palmitate metabolism, or lipolysis by the maternal or fetal placenta. Lipolytic activity of placental tissues was minimally affected by incubation with various proposed lipolytic activity of placental tissues was minimally affected by incubation with various proposed lipolytic agents. The data indicate that supply of fatty acids to the fetal pig may be limited by transfer of plasma fatty acids into the cytoplasm of placental cells or by regulatory enzymes for intermediate esterification; both types of limitations have been proposed to be influenced by fatty-acid binding proteins.

Animals↗
PubMed1991

A case-control study of the association between blood selenium and cystic ovaries in lactating dairy cattle.

We carried out a case-control study to investigate the association between the risk of developing cystic ovaries and the concentrations of Se in the blood of dairy cows. Cows were from dairy herds in the vicinity of Ithaca, NY. One hundred and thirty-two cystic ovary cases were identified; a similar number of herdmates who did not have cystic ovaries were selected as controls. Whole blood samples were collected from cystic cows and controls in which Se concentrations were determined. Milk samples also were collected and analyzed for concentrations of progesterone. Multivariate logistic regression analysis was used to identify the role of Se in the risk of developing cystic ovaries while controlling for other possible risk factors. Mean Se in blood concentration for cows with cystic ovaries (141 ng/ml) was similar to that of control cows without cystic ovaries (136 ng/ml). The concentration of progesterone in milk was significantly higher in controls than in cows with cystic ovaries. In the multivariate logistic regression analysis, cows with concentrations of Se in blood greater than 169 ng/ml had twice the risk of developing cystic ovaries compared with cows that had Se levels less than 108 ng/ml.

Age Factors↗
PubMed1990

Isolation, characterization, and developmental expression of pig intestinal fatty acid-binding proteins.

The goal of this study was to characterize and quantify intestinal fatty acid-binding proteins of the pig. Small intestinal mucosa from 13-19 kg pigs was homogenized and centrifuged to obtain cytosol. Isolation of fatty acid-binding proteins from delipidated cytosol was achieved using molecular sieve, oleic acid affinity, and ion exchange chromatography. Fatty acid-binding protein isolation was monitored using a fatty-acid binding assay in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Antisera to rat liver-fatty acid-binding protein cross reacted with an isolated intestinal fatty acid-binding protein of Mr = 13,000, whereas antisera to rat intestine-fatty acid-binding protein was not cross reactive with isolated pig intestinal proteins. These experiments identify a pig intestinal fatty acid-binding protein that exhibits strong immunochemical similarity to rat liver-fatty acid-binding protein. Cytosol prepared from intestinal mucosa of pigs at -4, 2, 4, 7, 15, 22, 28, and 35 d of age was assayed for fatty acid-binding protein activity. Preweaning fatty acid-binding protein activity in cytosol was maximal at 7 days of age when expressed as total jejunal fatty acid binding per kilogram bodyweight, intestinal or mucosal weight or milligram total protein. After weaning (21 d), fatty acid-binding protein activities declined to 28 days, but increased again by 35 days. Total soluble fatty acid-binding protein activity in pig intestine is regulated during postnatal development and this may account in part for the altered intestinal absorption of lipids observed in young pigs at weaning.

Journal Article↗