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Biomedical subjects

G C Randall

Publications and source records attributed to G C Randall.

35 records · Page 2Linked to original sources
PubMed1982

Attempts to isolate bovine leukemia and bovine syncytial viruses from blood, uterine flush fluid, unfertilized ova and embryos from infected donor cattle.

Blood leucocytes, sediments of uterine flush fluid (UFF), eggs and embryos from 25 BLV-positive donor cows were tested for bovine leukemia (BLV) and bovine syncytial (BSV) viruses by cocultivation with fetal lamb spleen cells and by applying syncytium induction and immunofluorescence tests. BLV was diagnosed in 11/15 (73.3%) leucocyte and 4/25 (16.0%) UFF-sediment specimens as compared to BSV in 14/15 (93.3%) and 21/25 (84.0%) of the similar specimens and neither BLV or BSV were found in 26 eggs and 60 embryos collected from 20 of the 25 cows. Detection of BLV antigens by immunofluorescence was hampered by the competitive replication of both BLV and BSV and competitive growth in indicator cells and uterine cells. As BLV has not been observed in cells of UFF sediments, it was probably isolated from leucocytes present in the lumen of uterus or from blood seeping out from inapparent vessel damage during flushing. Isolation of BLV in UFF sediments gives additional evidence to the concept of a transplacental transmission by a not yet elucidated mechanism. The high rate of BSV recovery from cells of UFF sediments indicated that this virus is more wide-spread than previously shown and that it may play a role in causing disorders of the reproductive tract.

Animals↗
PubMed1982

Changes in fetal and maternal blood at the end of pregnancy and during parturition in the pig.

Fetal and maternal blood gas tensions, pH, packed cell volume and glucose, fructose and lactic acid concentrations were monitored during the last two days of gestation, during parturition and and the first hour after birth. Blood samples were taken by means of indwelling catheters (implanted seven to 14 days before parturition) from 12 fetuses in seven sows. All fetuses were liveborn at a mean gestational age of 113.1 days. The significant finding was that all variables in fetal blood were stable during labour and, although mild hypercapnia was present during the last three hours, no significant changes in mean values were seen until those of samples taken within 15 minutes of birth. In some fetuses, no changes were seen until after birth, while in others pH and pO2 values declined during the last hour of fetal life. Immediately after birth a rapid increase in pO2 and decrease in pCO2 followed the onset of respiration. Blood pH fell during the first 30 minutes after birth and this fall was accompanied by increasing blood lactic acid concentrations. Blood glucose concentrations rose rapidly in the first 15 minutes after birth and were maintained during the first hour despite separation of the piglets from the sow. There was a transient, but significant, increase in packed cell volume during the period from 15 minutes before to 15 minutes after birth. Maternal values for all variables measured remained virtually unchanged during delivery.

Animals↗
PubMed1980

Chromosomal analysis of 159 bovine embryos collected 12 to 18 days after estrus.

One hundred and fifty-nine embryos were analysed in conjunction with embryo transfer studies. Chromosome preparations were made from small biopsy fragments of trophoblast, from large portions of trophoblast and the inner cell mass, or from the entire embryo. Results obtained from fragments were similar to those obtained from large portions of trophoblast and inner cell mass. No structural chromosomal abnormalities were observed. Single triploid, diploid-triploid and diploid-hexaploid and 66 diploid-tetraploid embryos were found. The 41.5% incidence of diploid-tetraploid embryos was relatively high, and appeared to be associated with a donor factor. The transfer of 49 biopsied and analysed embryos to recipients resulted in 15 pregnancies, seven with diploid-tetraploid embryos having up to 25% of polyploid cells. The diploid-triploid and diploid-hexaploid embryos were among the transfers that did not result in pregnancy. The low incidence of embryos with chromosomal abnormalities, excluding the diploid-tetraploid embryos, may have been due to the embryos being analysed at 12 to 18 days of age rather than at an earlier age before death or degeneration could have occurred.

Animals↗
PubMed1980

Collection, description and transfer of embryos from cattle 10--16 days after oestrus.

Of 226 donor cattle treated with PMSG to induce superovulation, 76.5% responded with 3 or more ovulations. Flushing at surgery or slaughter 10-16 days after oestrus recovered eggs and embryos that represented 49.3% of the number of ovulations. Of those recovered, 73.3% were embryos, an average yield of 4.0 embryos/treated cow or 4.8 embryo/flushed cow. The location of eggs and embryos was determined in 65 of the donors. Embryos and unfertilized eggs (6.1% of those recovered) were occasionally found in the oviducts. Empty zonae pellucidae were also found in the uterus on all days. The lengths, or diameters, of embryos were extremely variable within days and within donors, but mean values indicated logarithmic growth between Days 10 and 16. Eighty-four synchronous (+/- 1 day) recipients received single embryos, and 51 recipients twin embryos, by surgical transfer. Pregnancies were obtained in recipients up to Day 16 but not on Day 17, indicating the stage by which an embryo must be present to prevent luteolysis. The overall pregnancy rate at Day 42 was 50.4% and further 18.1% of the recipients exhibited extended oestrous cycles. Of 35 recipients that were allowed to go to term, 12 lost their pregnancies, most often between Days 42 and 63.

Abortion, Veterinary↗
PubMed1980

Fetal perfusion with maternal blood; a possible sequel to fetal catheterization in the pig.

Plasma gamma-globulin concentrations were increased in three catheterized pig fetuses in which the packed red cell volume rose rapidly after surgery, but were not increased in one fetus in which the packed cell volume remained normal. The increases in packed cell volume and gamma-globulin concentration were closely correlated. The source of the gamma-globulin was investigated in one sow with catheterized fetuses. Maternal proteins, identified by [125I]-labelling and gel diffusion, crossed to the circulation of the one catheterized fetus with an elevated packed cell volume but not to the other, in which packed cell volume remained normal, nor to two unoperated fetuses. The results suggest that vascular anastmosis between fetal and maternal circulations is a possible sequel to cannulation in this species.

Animals↗
PubMed1979

Studies on the effect of acute asphyxia on the fetal pig in utero.

8 term fetal pigs (110-112 days gestation) and one 97-day fetus were asphyxiated in utero by occlusion of the umbilical cord. Mean times to last gasp and last heart beat were 5.1 and 22.4 for term and 5.4 and 30.4 min for the 97-day fetus. Cord occlusion was followed by profound bradycardia and an increase in blood pressure which was maintained until gasping ceased. Profound acidemia, hypercapnia and hyperlactacidemia developed in all animals and values following asphyxiation were comparable with those seen in stillborn piglets. Liver and cardiac glycogen levels were lower in asphyxiated fetuses than in littermates but muscle glycogen levels were similar in both groups.

Animals↗
PubMed1977

Daily changes in the blood of conscious pigs with catheters in foetal and uterine vessels during late gestation.

1. Catheters were inserted into the foetal carotid artery and maternal middle uterine artery and vein in twenty foetuses from fifteen sows, 91-105 days pregnant. Blood samples were collected from foetal and maternal circulations for periods of 7-21 days after surgery.2. Blood gas tensions, pH, packed cell volume (PCV) and the levels of glucose, fructose and lactic acid in conscious pigs were followed in foetal and maternal bloods during late pregnancy.3. Foetal blood gas tensions, pH, PCV, lactic acid and glucose levels did not change markedly during the last 20-25 days of gestation. Blood fructose concentration fell during this period with the greatest change occurring after 100 days gestation. Foetal and maternal blood pH values were higher than those reported in the sheep, cow, mare and rhesus monkey.4. Small changes in P(CO2) and pH in foetal carotid blood were associated with similar changes in maternal uterine venous blood, so that gradients between sow and foetus remained relatively constant.5. Daily changes in maternal blood glucose levels were associated with smaller changes in foetal blood glucose and fructose levels. Blood glucose concentrations in foetal blood were generally 40-70% of maternal concentrations. Over-all relationships between maternal blood glucose and foetal blood fructose concentrations were masked by the independent fall in foetal fructose levels with age.6. The present findings have been compared with previous observations on acute, anaesthetized preparations in pigs, and chronic preparations in other domestic animals.

Animals↗
PubMed1976

Tissue glycogen and blood glucose and fructose levels in the pig fetus during the second half of gestation.

Tissue glycogen levels in the liver, cardiac ventricle, lung, thigh muscle, kidney and placenta were determined in pig fetuses of 60-112 days gestational age. Liver glycogen levels increased earlier in gestation than suggested by previous reports although the maximum rate of deposition occurred between 100 and 107 days. The time of deposition of muscle glycogen was similar to that of the liver. Lung glycogen levels peaked between 70 and 90 days but then fell rapidly in late gestation. Cardiac levels were similar at all ages studied. Blood fructose levels were high in younger fetuses but levels were lower in older fetuses and were falling rapidly between 107 and 112 days. Maternal blood contained only traces of fructose. Fetal blood glucose levels were lower than maternal levels and appeared to be more closely related to maternal levels than to the gestational age of the fetuses.

Animals↗
PubMed1971

The relationship of arterial blood pH and pCO2 to the viability of the newborn piglet.

Clinical observations were made on the majority of 749 newborn piglets from 75 litters and the blood pH and pCO(2) levels in samples taken from an umbilical artery were determined in 299 of these piglets. A method of individual clinical assessment was developed which reduced the effect of subjective error on the evaluation of viability at the time of delivery. Blood samples were collected from the umbilical artery prior to the onset of respiratory movements and it was found that increased acidemia and hypercapnia were associated with reduced viability. The pH values in severely depressed piglets were between 6.50 and 6.95 and pCO(2) values between 105 and 185 mm Hg, whereas in the fully viable animals, the ranges were 7.10-7.42 and 46-75 mm Hg respectively. It was concluded that a large proportion of the mortality and reduced viability at the time of delivery could be attributed to intra-uterine asphyxia.

Animals↗