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Biomedical subjects

D E Noakes

Publications and source records attributed to D E Noakes.

At least 73 records · Page 4Linked to original sources
PubMed1984

Pelvic dimensions, bodyweight and parturition in rare breeds of sheep.

External pelvic measurements were made in 837 adult ewes of 21 different breeds, the majority of which were rare breeds. The pelvic measurements were the intertuber coxal diameter, the distance between the lateral tuber ischii and medial tuber ischii and the rump length. There was a considerable breed variation with the Soay ewes having the smallest and the Suffolk the largest pelvic dimensions. However when the relationship between pelvic size and ewe's bodyweight was compared, the ratio of the medial tuber ischii:bodyweight and sum of four pelvic dimensions:bodyweight of the Soay was over twice that of the Suffolk ewes. When the size of the pelvis was related to the lamb's birth weight the Soay's was relatively larger. Dystocia caused by feto-maternal disproportion occurred in 19 ewes, all with singletons. In 16 cases involving four different breeds the birth weights of the lambs were significantly larger than those lambs which were born normally.

Analysis of Variance↗
PubMed1984

The effect of experimental induced hypocalcaemia on uterine activity in the sow during parturition and post-partum.

Uterine activity was measured by monitoring intrauterine pressure changes using ballon-tipped catheters placed in the lumen. An infusion rate of Na(2)EDTA of 35 mg/Kg/h gave a chelation rate equivalent to the rate of calcium mobilisation, and when infused at a level greater than this, resulted in a reduction in plasma calcium concentrations and a concomitant reduction in uterine activity. In three of the four sows infused intrapartum, there was complete cessation of uterine activity; however, plasma calcium concentrations of less than 6 mg 100 ml resulted in a reduction in uterine activity at this stage of parturition. The uterus of the sow post-partum appeared to be more sensitive to the effects of hypocalcaemia with reduced uterine activity when plasma calcium concentrations fell below 8.2 mg 100 ml and complete cessation of activity between 6 and 7 mg 100 ml . Although there was evidence of a delay in the expulsion of piglets in the hypocalcaemic sows, there was no evidence of an increased number of stillborn piglets compared with the two control sows.

Journal Article↗
PubMed1984

Spontaneous uterine activity and plasma progesterone and oestrogens in the ewe with live and stillborn lambs.

Peripheral plasma progesterone and oestrogen concentrations were measured during late pregnancy and the parturient period in 12 ewes producing live lambs and three others producing stillborn lambs. Progesterone values started declining by 10 days before lambing but at minus 24 hours were still 6.1 +/- 3 ng/ml in the ewes bearing live lambs; during the last 24 hours progesterone was significantly lower in the ewes producing stillborn lambs. Oestrogens reached a maximum level of 550 +/- 280 pg/ml at the time of delivery and declined rapidly to basal values shortly after lambing. Oestrogens did not rise at lambing in the ewes producing stillborn lambs. In seven of the 12 ewes bearing live lambs, uterine activity, as determined by intrauterine pressure changes, was recorded throughout parturition and compared with the plasma values for progesterone and oestrogens. It was found that there was a highly significant positive correlation between uterine activity and plasma oestrogen concentrations, and a highly significant negative correlation between uterine activty and both plasma progesterone concentrations and the progesterone: oestrogen ratio.

Journal Article↗
PubMed1984

The effect of experimentally induced hypocalcaemia on uterine activity at parturition in the ewe.

The effect of hypocalcaemia experimentally induced by the intravenous infusion of ethylene-diamine tetraacetic acid, disodium salt (Na(2)EDTA) upon myometrial activity at parturition was studied in eleven ewes. Infusions of Na(2)EDTA were performed during first stage of labour (three animals), second stage (four animals), third stage (three animals) and postpartum (two animals); one in the latter group had been previously treated during second and third stages. Uterine activity was recorded using balloon-tipped catheters surgically implanted into the uterus and was expressed in Montevideo Units (M.U.). Plasma calcium (nonchelated) concentrations were monitored throughout the infusion. Induced hypocalcaemia resulted in a reduction of the activity of the uterus when Na(2)EDTA was administered during the first stage of labour. In the ewes infused during the second stage of labour, there was difficulty in reducing the activity of the uterus and, consequently, in delaying parturition. Reduction in uterine activity was easier in the ewes infused during the third stage of labour and during postpartum. Uterine activity started decreasing when plasma calcium concentrations were 6.6 and 7.1 mg/100 ml in the ewes infused during third stage of labour and postpartum, respectively, compared with 4.9 mg/100 ml in those infused during first stage of labour; the difference between this last group and the first two was significant (p < 0.05). After the end of the infusion, the plasma calcium started rising and normal uterine activity quickly resumed.

Journal Article↗
PubMed1983

Influence of insulin and substrate concentration on protein synthetic rate in fetal tissues.

The influence of fetal plasma substrate and insulin concentrations on the fractional synthesis rate or turnover of the mixed proteins in the organs of fetal lambs was calculated from measurements of the rate of uptake of L-14C lysine by the protein in the steady state in utero. The control values for protein synthesis rate in the fetal organs of Welsh mountain ewes, 130 to 140 days' pregnant, were similar to those previously observed in the fetuses of Border Leicester ewes: the mean turnover rates were 38, 72, 40 and 63 per cent per day for the brain, liver, cardiac muscle and the placenta respectively; that for skeletal muscles was 6.8 per cent per day; the corresponding half lives were 2.15, 1.27, 1.8 and 1.42 days respectively and 11.3 days for skeletal muscle. A fivefold increase in the plasma glucose levels had no influence on protein turnover rate over a six hour period. A fourfold increase in the concentration of some amino acids, following a mixed infusion, decreased turnover rate in brain, heart and liver. The half life was increased by 30 per cent, but a small reduction in half life was observed in skeletal muscle. Insulin caused a fall in intracellular lysine concentration in skeletal muscle and in plasma, which suggests that the hormone can reduce muscle protein catabolism in the fetal lamb in the last trimester of gestation. Enhancement of synthesis rate occurred in the presence of the amino acid infusions only; the half life of the proteins was reduced by a factor of three. Insulin also increased placental protein synthesis rate by 50 per cent but had no influence on the other tissues studied.

Amino Acids↗
PubMed1983

Method for chronic catheterisation of the amniotic sac in cattle.

The chronic catheterisation of the amniotic sac of eight pregnant cows of 180 to 200 days gestational age is described using an indwelling catheter of polyvinyl tubing. Although strict asepsis was followed, the main problem encountered was preventing contaminant bacteria from overwhelming the fetus, causing its death. This was successfully achieved in four animals, three of which received a mixture of ampicillin and cloxacillin sodium intra-amniotically and parenterally in the dam. Daily sequential samples of amniotic fluid were readily obtained until just before fetal death.

Amnion↗
PubMed1982

Effects of exogenous oestrogen and experimentally induced endometritis on absorption of sodium benzylpenicillin from the cow's uterus.

The effects of oestradiol benzoate or of experimentally induced infection on the absorption of sodium benzylpenicillin from the uterus were investigated in three groups of clinically normal, non-pregnant, Friesian cows. All were at day 12 following the day of oestrus. Oestradiol benzoate in oil was administered either into the uterus or intramuscularly one hour before the infusion of 22,000 iu/kg of sodium benzylpenicillin. The dose of oestradiol benzoate was 10 mg, apart from one cow in each group which received 25 mg. Inflammation was induced by infusing a suspension of Corynebacterium pyogenes in Ringer's solution into the uterus, 11 to 18 hours before penicillin infusion. The degree of absorption of penicillin was greater in all three groups than that previously determined in cows given penicillin alone at the same stage of the cycle. The results indicate that factors which might affect blood flow to the uterus may also influence the absorption of sodium benzylpenicillin from the uterus.

Animals↗
PubMed1981

Measurement of fetal tissue protein synthetic rate in the lamb in utero.

The fractional synthesis rate of the mixed proteins in the organs of fetal lambs at 123 to 130 days' gestation were calculated from measurements of the rate of uptake of L14Clysine by the protein in the steady state in utero. The fractional synthesis rates were 82, 121 and 99 per cent per day for the brain, liver and cardiac muscle respectively; the average values of 40 per cent for skeletal muscle was significantly smaller than for the other tissues. The fetal fractional protein synthetic rates measured were similar to those of the newborn lamb, but faster than in the adult sheep by a factor of 10. Similar differences in synthesis rates have been observed between the young and adult rat and the possible reasons for the change in fractional rate during growth are discussed.

Animals↗
PubMed1980

Effect of gonadotrophin releasing hormone on levels of luteinising hormone in cattle synchronised with dinoprost.

Synchronisation of oestrus was achieved in a group of three cows and two heifers with dinoprost. Sixty-six hours after the second injection of dinoprost, 0.125 mg synthetic gonadotrophin releasing hormone (GnRH) was given intramuscularly. Concentrations of luteinising hormone (LH) were monitored in peripheral blood and close grouping of preovulatory LH peaks was seen around 2.5 hours after injection of GnRH.

Animals↗
PubMed1980

The effect of the stage of the oestrous cycle and exogenous sex steroids on the transport of starch grains through the genital tract of the ewe, a preliminary study.

The starch grain test was studied in two ewes to determine the effect of the stage of the oestrous cycle on their transport through the Fallopian tubes. There was very little difference when the test was performed at oestrus or day 10 of the oestrous cycle. Bilateral ovariectomy had very little effect on the transport of starch grains. When progesterone in oil was administered by intramuscular injection to a bilaterally ovariectomised ewe and an intact ewe there was a marked increase in the number of grains which were recovered. Oestradiol benzoate in oil delayed the recovery of grains and reduced their numbers.

Journal Article↗
PubMed1979

The use of the starch grain and phenolsulphonphthalein tests to investigate infertile cows.

The starch grain and phenolsulphonphthalein (PSP) tests were used to investigate the patency of the fallopian tubes in five "repeat breeder" cows. Evidence of tubal lesions was determined in three cows on rectal palpation. Using the starch grain test, bilateral occlusion was determined in three animals, left sided occlusion was determined in one and right sided occlusion in another. Using the PSP test there was evidence of bilateral occlusion in two of the four coes which were tested. In four cows the genital organs were examined visually and by palpation at laparotomy and in two cows tubal occlusion was confirmed when they were flushed with saline, and patency restored. In one animal both ovaries were almost completely encapsulated, while in the fourth adhesions involving the fimbriae occluded the ostia. There were broken down and this cow was the only one which subsequently conceived.

Animals↗
PubMed1979

Plasma progesterone and luteinising hormone levels in cattle after synchronisation of oestrus with dinoprost.

The plasma levels of progesterone and luteinising hormone (LH) were monitored in a group of cattle after pretreatment with two injections of 25 mg dinoprost. Close groupings of preovulatory LH peaks were observed and the possible significance of this is discussed. Based on the findings of this study, supporting evidence is provided for the timing of insemination after injection of cattle which have been synchronised for oestrus with dinoprost.

Animals↗
PubMed1979

Evaluation of uterine tube function in pony mares.

Two experimental procedures were investigated in order to assess their usefulness in diagnosing occlusion of the equine uterine tube. The starch grain test, which involves the injection of a starch suspension onto the ovary and the subsequent recovery of starch from the cervix, proved to be safe and reliable. Each tube could be investigated separately. It was found that when starch was injected onto the ovulating ovary on the day of ovulation, there was a delay of four to seven days before starch was recovered from the cervix. The phenolsulphonphthalein (PSP) test, which involves the deposition of dye solution into the uterus and its subsequent identification in urine after peritoneal absorption, was not reliable. Contamination of the urine occurred per vaginum, and the test was not unilaterally specific.

Animals↗