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Biomedical subjects

R T Stone

Publications and source records attributed to R T Stone.

At least 91 records · Page 5Linked to original sources
PubMed1989

The relationships of birth weight, preweaning gain and postweaning gain with the bovine major histocompatibility system.

A total of 739 cattle from nine breeds maintained at the Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska were tested for 42 class I antigens of the bovine major histocompatibility system (BoLA). Each antigen appears to be the product of a distinct co-dominant allele of the BoLA-A locus. The number of antigens present in each breed ranged from a minimum of 10 in Hereford to a maximum of 21 in Charolais cattle. There were large differences among breeds in the frequencies of antigens. The effect of each antigen on birth weight, preweaning weight gain and postweaning weight gain was estimated in a gene substitution model. Each breed was analyzed separately. There were significant effects of some BoLA antigens on birth weight, preweaning weight gain and postweaning weight gain, which is consistent with previous reports showing associations between the major histocompatibility system and growth parameters in mice, rats and pigs. However, further research is necessary to confirm these findings and to determine the biological mechanisms underlying these associations.

Animals↗
PubMed1989

Isolation and characterization of recombinant cDNA clones corresponding to developmentally regulated genes in pig liver.

To identify clones that corresponded to developmentally regulated genes in pig liver, recombinant cDNA libraries were constructed from early fetal (d 40), late fetal (d 110) and adult liver mRNA. Each library was screened by probing with total cDNA prepared from mRNA at different stages of development. Nine clones that gave distinct developmental patterns when hybridized to liver RNA isolated from various stages of development were subsequently isolated and partially sequenced. The cognate proteins for seven of these clones were identified by searching a national DNA sequence resource (Bionet) for similar sequences. Clones hybridizing to mRNA that was most abundant early in development were alpha fetoprotein, alpha 1 antiprotease, alpha globin and an unidentified clone. The mRNA for beta and gamma fibrinogen were most abundant perinatally. The abundance of mRNA for albumin, haptoglobin and a second unidentified clone was low in fetal liver, but increased to adult levels between birth and 3 d of age. These clones provide probes to study the relationship between factors affecting fetal growth and expression of specific genes throughout the development.

Animals↗
PubMed1988

Breed differences in the distribution of BoLA-A locus antigens in American cattle.

A total of 627 cattle representing seven breeds from south central Nebraska, USA were tested for 37 BoLA antigens which behave as products of 37 distinct alleles of the class I BoLA-A locus. Four antigens were absent from all breeds tested. The other antigens showed marked and statistically significant differences in breed distribution. There was no evidence for blank (null) alleles. The number of alleles in each breed ranged from 10 to 20. The Hereford and Simmental populations tested were less polymorphic than the Angus, Brown Swiss, Charolais, Gelbvieh and Limousin populations.

Alleles↗
PubMed1988

Identification of genetic variation in the bovine major histocompatibility complex DR beta-like genes using sequenced bovine genomic probes.

Two bovine genomic clones that crosshybridize with HLA-DR beta cDNA have been isolated. Nucleotide sequence analysis of the beta 1, beta 2 and transmembrane (TM) exon regions for one of these clones revealed 70, 89 and 86% identity with the corresponding HLA-DR beta exons. Stop codons are present in the beta 1 and TM exons and a single base deletion toward the 3' end of the TM exon negates the consensus sequence for exon/intron splicing. Therefore, we conclude this is a bovine DR beta-like pseudogene, BoDR beta I. Exon-containing regions have been used as probes in Southern blot analyses of bovine genomic DNA digested with EcoRI. The beta 2 exon of BoDR beta I results in prominent bands of 18.9, 7.8, 7.2, 6.4, 5.6, 3.6, 3.0 and 2.7 kb. Polymorphisms were observed for all but the 18.9 kb band and at least three of these bands were identified in each of the 185 animals sampled. A probe containing the TM exon of BoDR beta I hybridizes only to the 5.6- and 3.6-kb bands, suggesting that these are allelic bands corresponding to this pseudogene. Results from hybridizations of a TM exon-containing probe of the second bovine DR beta-like clone (BoDR beta II) suggest that the 6.4- and 2.7-kb bands correspond to this second bovine gene. A nonpolymorphic 8.1-kb band results from a probe containing the BoDR beta I beta 1 exon. Major differences in frequency for the 6.4/2.7 alleles were found for the four breeds sampled.

Amino Acid Sequence↗
PubMed1988

Influence of maternal obesity on fetal development in pigs.

Fetuses from linebred lean (L) and linebred obese (O) and reciprocal crossmatings were examined at 110 d of gestation for line, maternal and heterotic effects. There was no significant heterotic effect for any trait measured. A significant maternal effect was observed for adipose tissue lipoprotein lipase (LPL) activity and for serum triglycerides. The enzyme activity and triglycerides concentration were higher in fetuses from O dams than in fetuses from L dams. In a lipid clearance test, no maternal effect was observed for changes in serum concentrations of triglycerides and free fatty acids or in optical density (associated with the disappearance of injected Liposyn). Linebred O fetuses exhibited higher LPL activity in both the biceps femoris muscle and sc adipose tissue compared with linebred L fetuses. The LPL activity of the adipose tissue was higher than that of the skeletal muscle. The percentage of dry matter, percentage of triglycerides and protein/DNA were higher in the muscle of linebred O fetuses than in that of linebred L fetuses. Based on tissue LPL activity and on muscle compositional traits, linebred O fetuses were more mature at 110 d of gestation than were the linebred L fetuses. Maternal obesity had little detectable influence on fetal development of the pig when measured at 110 d of gestation.

Animals↗
PubMed1987

Cloning and developmental regulation of alpha 1 acid glycoprotein in swine.

A cDNA clone of porcine alpha 1 acid glycoprotein (alpha 1AGP) has been isolated and sequenced. Sequence homologies between porcine, human, and rat indicate that porcine alpha 1AGP is similar in structure to the rat and human proteins. RNA blots from days 40, 60, 80, and 110 fetal, newborn, and adult livers showed that alpha 1AGP mRNA is relatively abundant throughout fetal development, particularly at the later stages and in the newborn; there is a rapid decline in abundance following birth. From birth to 3 days of age, there is a three- to four-fold decline in abundance, and alpha 1AGP mRNA is approximately 100 times less abundant in the adult liver than in that of perinatal pigs. Southern blots showed that alpha 1AGP is probably a single-copy gene. The isolation of a cloned cDNA for porcine alpha 1AGP provides a tool to investigate the molecular mechanisms involved in the developmental regulation of the gene and to correlate changes in gene expression during development with fetal growth and well being.

Amino Acid Sequence↗
PubMed1985

Blood parameters and body composition in fetuses from reciprocal crosses of genetically lean and obese swine.

Lines of swine previously selected for either high backfat (obese) or low backfat (lean) were investigated to determine the effect of maternal obesity and the relationship between serum parameters and body composition. Fetal weight, percentage body protein, fat, fat-free organic matter and ash, and serum concentrations of albumin, growth hormone, triiodothyronine, and cortisol were compared in fetuses from straight line and reciprocal crosses at 110 days of gestation. Fetuses from the obese line weighed less but had a greater percentage body protein, fat, and fat-free organic matter than did fetuses from the lean line. Serum concentrations of albumin and triiodothyronine were less whereas those of growth hormone were greater in fetuses from the lean line compared to fetuses from the obese line. Values for these parameters in fetuses from the reciprocal crosses were generally intermediate to those of fetuses from the lean and obese lines. Comparisons of fetuses from the reciprocal and line crosses by linear contrast showed that the observed differences were mainly due to the average genetic effect of individual fetal genotypes and not due to maternal effects. Correlations computed from the residual variance showed a positive relationship between percentage body protein, serum albumin, and triiodothyronine while percentage body fat was not correlated with any of the other traits. Serum growth hormone was negatively correlated with fetal weight. We conclude that there is no apparent maternal effect of obesity or relationship of fetal fat content with any of the other variables measured in these lines of swine at the stage of fetal development at which these determinations were made.

Animals↗
PubMed1985

Relationships of birth weight and pre-nursing concentrations of serum albumin to survival and growth rate in swine.

Data from 29 litters of swine were analyzed to estimate the relationships of birth weight and pre-nursing concentrations of serum albumin to survival and daily gain from birth to 14 d and from 14 to 28 d. Means and standard deviations of birth weight and serum albumin were calculated within each litter and used as analytical units. Positive linear partial regression coefficients were detected for effects of serum albumin on birth weight (P less than .01) and daily gains (P less than .05). As both serum albumin and birth weight increased, survival also increased but at a decreasing rate (P less than .05). Survival decreased as the standard deviations of serum albumin (P less than .05) and the birth weight (P less than .10) increased. Daily gain from 14 to 28 d of age increased (P less than .10) as the standard deviation of serum albumin varied above or below about .5 mg/ml. The linear effect of birth weight on daily gain from birth to 14 d of age was positive (P less than .01), whereas daily gain from 14 to 28 d of age increased as birth weight varied above or below about 1.3 kg (P less than .01). Daily gains during the first and second periods also increased as the standard deviation of birth weight varied above or below .3 kg (P less than .05) and .25 kg (P less than .001), respectively. Fitting birth weight and serum albumin simultaneously into the statistical model accounted for 57% of the variation in survival, a level at least twice as great as previously reported. It is speculated that use of a marker of physiological maturity, such as pre-nursing concentrations of serum albumin, might facilitate selection for survival.

Aging↗
PubMed1984

Relationship of alpha-fetoprotein and albumin in fetuses and neonates from genetically lean and obese swine.

The relationship between alpha-fetoprotein and albumin during fetal development in two genetic lines of swine selected for either high backfat (obese) or low backfat (lean) has been investigated. Differences in serum concentrations, in vitro synthesis by liver slices, and cell-free translational activity of total tissue RNA for alpha-fetoprotein and albumin were determined at days 40, 60, and 80 of gestation and in newborn pigs. Serum concentrations of alpha-fetoprotein tended to be greater in pigs from the lean line compared to those from the obese line during the fetal stages, but no differences were observed in newborn pigs. Similar differences between the two lines were observed for alpha-fetoprotein synthesis by liver slices and cell-free mRNA translational activity. Serum albumin concentrations and the relative synthesis by liver slices were between 2- and 3-fold greater in the obese pigs compared to the lean pigs at days 60 and 80 of gestation and at birth. Albumin mRNA activity increased with fetal age in a manner similar to increases observed in serum concentrations and in vitro synthesis; however, no differences in the cell-free albumin mRNA activity in total liver RNA extracts from the two lines could be detected. The overall pattern of increasing albumin and decreasing alpha-fetoprotein concentrations in serum with increasing fetal age was similar in the two lines. Results from dot-blot hybridizations of total liver RNA to a heterologous recombinant mouse albumin cDNA probe suggested that increasing albumin synthesis with increasing age can be attributed to an increasing abundance of albumin mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Factors affecting growth and survival of neonatal genetically obese and lean swine: cross fostering experiments.

Obese and lean lines of pigs were developed previously by genetic selection for thick and thin backfat thickness, respectively. A greater proportion of these obese than lean pigs survive to weaning. A cross-fostering experiment was designed to study neonatal piglet growth and to attempt to decipher some of the causes of the increased survival rate. At about 24 h postpartum, lean and obese sows were paired, the litters standardized to six pigs and three pigs from each sow transferred to a dam of opposite genetic line. The smaller birthweight of obese than lean piglets and the lesser growth of either obese or lean pigs raised on obese compared to lean sows were both observations that might support greater survival of lean rather than obese piglets. Positive factors that might contribute toward the greater survival of obese than lean piglets were the greater lipid content of milk from obese than from lean sows during the first 2 wk postpartum and possibly greater physiological maturity of obese than lean pigs at birth as reflected in greater hemoglobin, hematocrit, plasma protein and plasma albumin.

Animals↗
PubMed1984

Porcine growth hormone and prolactin: concentrations in the fetus and secretory patterns in the growing pig.

The concentrations of growth hormone (GH) and prolactin (PRL) were measured in serum harvested from umbilical arterial blood of fetal pigs from 40 to 112 days of gestation and the secretory patterns of these hormones determined in plasma obtained from jugular blood samples at 5, 13, 18, and 24 wks after birth. Fetal serum concentrations of GH appeared to parallel the changes in fetal weight until approximately 75 days of fetal age, after which minimal change in GH concentrations occurred. The PRL concentrations in fetal sera reached 1 to 1.5 ng/ml on days 40 to 50 of fetal age and declined approximately 50% through 80 days of fetal age. Near day 80 of gestation, fetal serum PRL concentrations began to increase from nadir concentrations to 3 ng/ml on day 112. In postnatal pigs, the level of GH secretion declined with age and this decline was mainly associated with a reduction in the amplitude of secretory peaks. Decreases in incidence and amplitude of PRL secretory peaks were the only significant age-associated changes observed in PRL secretion postnatally.

Aging↗
PubMed1982

The relationship of fetal weight to serum albumin and alpha-fetoprotein in swine.

The within-litter relationship of fetal weight to fetal serum albumin and alpha-fetoprotein (AFP) was investigated at d 30 to 40, 45 to 50, 50 to 60, 75 to 85 and 90 to 105 of gestation in swine. Regression equations were calculated on individual litters and regression coefficients pooled across litters within each gestational age group. Coefficients for the regression of albumin on fetal weight (microgram . ml-1 . g fetus-1) were significant over all groups and ranged from 22.5 +/- 6.6 to d 45 to 50 to .7 +/- .2 at d 95 to 105. There was no significant relationship between AFP levels and fetal weight at any gestational age. Unilateral ovariectomy-hysterectomy was performed before mating to study effects of uterine crowding on the relationship of fetal weight to AFP and albumin. Although the total number of ovulations was not different from controls, this treatment resulted in only about 1.3 more fetuses/uterine horn compared with controls at either d 40 or 60 of gestation. Fetal weights in crowded litters were not different from controls. However, AFP levels in fetuses from crowded litters were lower than in control fetuses at d 40 (4.5 +/- .1 vs 6.7 +/- .5 mg/ml). Albumin levels in crowded fetuses were significantly lower than in controls at d 60 (342 +/- 50 vs 653 +/- 41 micrograms/ml). Because none of these differences in albumin or AFP could be attributed to variation in fetal weight or fetal number at the time of sample collection, it is possible that more extreme uterine crowding earlier in development resulted in these differences. These results demonstrate that fetal serum albumin concentrations are related to fetal weight when analyzed on a within-litter basis and that unilateral ovariectomy-hysterectomy may affect serum concentrations of both AFP and albumin early in fetal development. Future studies involving the regulation of synthesis of these proteins at the cellular level during development should provide information as to how factors affecting overall fetal growth and development influence the expression of a single gene. Previously, such markers that are amenable to study early in development have been lacking.

Animals↗
PubMed1980

Uptake of 5-fluorouracil during isolated perfusion of the canine liver.

This study describes a technique of hepatic isolated perfusion in dogs. The uptake of 14C-labeled 5 fluorouracil (5-FU) by the normal canine liver was fourfold greater when isolated perfusion was used than when peripheral intravenous administration or hepatic artery infusion were applied. Systemic leakage of 5-FU was small during, and even following, hepatic isolated perfusion. This technique, which maximizes chemotherapy delivery to the liver while minimizing systemic toxicity, may be useful in the treatment of primary and metastatic hepatic malignancies.

Animals↗
PubMed1979

Massive lower gastrointestinal bleeding from intestinal varices.

Lower gastrointestinal bleeding from intestinal varices cannot readily be detected at operation; hence, preoperative identification is important. Our experience with six patients having sudden, massive bleeding per rectum from intestinal varices suggests a group of common findings. These patients had cirrhosis, no blood in the stomach or duodenum, characteristic mucosal imprints on barium enema, or direct visualization of varices on sigmoidscopy or colonoscopy. Only two had demonstrable esophageal varices. The diagnosis was confirmed and the site of the varices localized on the venous phase of selective mesenteric angiography in five patients. Varices were located in the duodenojejunum in two, in the cecum and ascending colon in two, and in the rectum and sigmoid colon in two patients. Three patients were treated nonoperatively with transfusion and intraarterial infusion of vasopressin into the superior mesenteric artery; one died. One patient with cecal varices had a right hemicolectomy that controlled the bleeding, but progressive hepatic failure resulted in postoperative death. The remaining two patients had successful decompression of left colonic varices by portasystemic shunt.

Aged↗
PubMed1978

Patency of biologic and prosthetic inferior vena cava grafts with distal limb fistula.

A 5-cm segment of the infrarenal inferior vena cava (IVC) in 27 dogs was excised and replaced with a prosthesis of bovine heterograft, venous allograft, or polytetrafluoroethylene (ePTFE). On completion of the IVC graft, a side-to-side femoral arteriovenous fistula was constructed in the thigh. At six weeks an IVC venogram was obtained to assess patency and the femoral arteriovenous fistula closed. After three months, the dogs were reexplored, the grafts were removed, and patency was determined. Patency of the venous allograft and bovine heterografts were maintained with the arteriovenous fistula in only two dogs and further deteriorated after closure of the fistula so that only one dog in each group had a patent IVC graft at the end of three months. Eight of the 13 e-PTFE prostheses were patent at six weeks and remained patent for three months after fistula closure. Light and electron microscopy of the patent e-PTFE specimens excised at three months showed regenerative endothelium. Expanded e-PTFE was the most suitable prostheses for replacement of the IVC, resulting in 61% patency three months after closure of a distal arteriovenous femoral fistula.

Animals↗