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C Chapman

Publications and source records attributed to C Chapman.

At least 127 records · Page 7Linked to original sources
PubMed1988

Microdialysis measurement of oxytocin, aspartate, gamma-aminobutyric acid and glutamate release from the olfactory bulb of the sheep during vaginocervical stimulation.

Concentrations of oxytocin and amino acids were measured in microdialysis samples taken from the olfactory bulbs of 5 conscious, oestrogen-treated ewes before, during and after a 10-min period of vaginocervical stimulation. Results showed that vaginocervical stimulation induced significant increases in concentrations of oxytocin, aspartate, gamma-aminobutyric acid (GABA) and glutamate in dialysis samples. Concentrations of other amino acids measured were not affected. These findings show that vaginocervical stimulation produces significant changes in neurochemical release in the olfactory bulbs of sheep. Such changes may be involved in the induction of maternal behaviour of the olfactory recognition of offspring.

Animals↗
PubMed1988

Intracranial dialysis measurement of oxytocin, monoamine and uric acid release from the olfactory bulb and substantia nigra of sheep during parturition, suckling, separation from lambs and eating.

Intracranial dialysis was used to measure the release of oxytocin (OXY), monoamines and their metabolites and uric acid (UA) from the substantia nigra (SN) and olfactory bulb (OB) of sheep during parturition, suckling, separation from lambs and eating. Results showed that OXY concentrations increased significantly during parturition, suckling and eating in the SN and during parturition and suckling in the OB. Concentrations of dopamine (DA) increased significantly in the SN during suckling and eating and in the OB during parturition and suckling. The dopamine metabolite, homovanillic acid, also increased significantly in the SN during parturition. Concentrations of the noradrenaline metabolite, 4-hydroxy-3-methoxyphenylethan-1,2-diol (MHPG) and the purine metabolite, UA, were significantly raised during parturition, suckling and separation from the lambs in the SN and increased UA levels were also found during eating. In a separate experiment it was confirmed that OXY was detectable in homogenates of both the SN and the OB. These results show that, in the sheep, OXY and DA release in the SN is associated with maternal and ingestive behaviour whereas similar release in the OB may only be related to maternal behaviour. Release of MHPG in the SN may be associated with maternal behaviour and/or stress.

Animals↗
PubMed1988

Of mice and Merle.

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Home Care Services↗
PubMed1988

Operative treatment of Crohn's ileocolitis complicated by ileosigmoid and ileovesical fistulae.

Ileovesical and ileosigmoid fistulae were found to coexist in 22 patients with Crohn's ileocolitis. Persistent or recurrent urinary tract infection was a complaint in all cases, and 11 patients reported pneumaturia and/or fecaluria. Thus, bladder involvement was either suspected or clinically apparent in each patient. The cystogram was the best confirmatory test for the ileovesical fistula (positive in 9 of 22 patients). The coexistence of the sigmoid fistula was best diagnosed on intestinal radiographs (positive in 9 of 22 patients); there were no clinical signs of its presence. The coexistence of ileosigmoid and ileovesical fistulae was the sole indication for operation in two patients. In all others, a combination of factors required surgical therapy. An ileocolonic resection with primary intestinal anastomosis was performed in 16 patients and exteriorization was performed in six patients. The sigmoid defect was closed primarily in 16 patients and required wedge resection in the other six patients. The bladder defect was sparingly excised and closed with absorbable sutures. All patients recuperated without anastomotic leaks, bladder leaks, or persistent cystitis. This experience indicates that coexisting ileosigmoid and ileovesical fistulae may add complexity to an ileocolonic resection for Crohn's disease, but is not a difficult management problem for the gastrointestinal surgeon.

Adolescent↗
PubMed1988

Opioid-noradrenergic interactions in the neurohypophysis. I. Differential opioid receptor regulation of oxytocin, vasopressin, and noradrenaline release.

The actions of opioids on electrically evoked release of oxytocin, vasopressin, and noradrenaline-using the [3H]-noradrenaline technique-from the rat neurohypophysis were examined in vitro. Antagonism of the action of endogenous neurohypophysial opioids with naloxone enhanced release of peptides and [3H]-noradrenaline differentially. Naloxone enhanced oxytocin release by 100 and 173% in two series of experiments (ED50 7 x 10(-7) M), whilst vasopressin release was enhanced by only 30 and 20%, respectively. [3H]-noradrenaline release was maximally enhanced by 41% (ED50 2 x 10(-7) M). We examined the opioid receptor subtypes mediating these effects using selective receptor agonists. The kappa-agonist U-50,488H inhibited oxytocin and vasopressin release to a similar extent, but did not modify [3H]-noradrenaline release. The effects of U-50,488H were completely prevented by a tenfold molar excess of naloxone. The mu-agonist (D-Ala2, MePhe5 Gly-ol)-enkephalin also failed to inhibit [3H]-noradrenaline release and caused only a minor inhibition of oxytocin and vasopressin secretion. The delta-agonist (D-Pen2, D-Pen5)-enkephalin was without effect. We conclude that (1) kappa-receptors sensitive to U-50,488H mediate opioid inhibition of secretion from oxytocin and vasopressin nerve terminals; (2) when opioid actions are blocked by naloxone, opioid peptides within the neurohypophysis are shown to exert a much greater influence over oxytocin compared to vasopressin terminals; (3) neurohypophysial opioids also regulate release from noradrenergic terminals, although the nature of the receptors involved remains unclear, and (4) kappa-receptors can mediate inhibition of neurohormone secretion by an action independent of the neurohypophysial noradrenergic innervation.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1988

Opioid-noradrenergic interactions in the neurohypophysis. II. Does noradrenaline mediate the actions of endogenous opioids on oxytocin and vasopressin release?

The function of noradrenaline in the rat neurohypophysis was investigated by examining the effects of selective adrenergic receptor agents on electrically evoked release of oxytocin, arginine vasopressin, and noradrenaline using the [3H]-noradrenaline technique. Since endogenous opioids in the neurohypophysis suppress release of both neurohormones and of noradrenaline, we assessed the role of noradrenaline in mediating opioid actions on neurohormone secretion by examining modification of the action of the opioid antagonist naloxone by adrenergic receptor agents. The data suggest (1) that in addition to opioid receptors, 'presynaptic' alpha 2-receptors regulate release from neurohypophysial noradrenaline terminals; (2) noradrenaline released from neurohypophysial terminals acts on beta- and alpha 1-receptors to facilitate both oxytocin and arginine vasopressin release: this action only becoming evident at elevated levels of endogenous noradrenaline release attained following removal of presynaptic opioid or alpha 2-regulation, and (3) opioid peptides within the neurohypophysis act to inhibit oxytocin and, to a lesser extent, arginine vasopressin secretion, partly through inhibiting release of facilitatory noradrenaline. We propose a model in which opioids act in the neurohypophysis both independently of noradrenaline via kappa-receptors on neurosecretory terminals or pituicytes and also via interaction with the noradrenaline system.

Animals↗
PubMed1988

Plasma vasopressin and oxytocin levels in intact goats and in castrated goats given testosterone.

Oxytocin, vasopressin, cortisol and testosterone levels in the plasma were measured by radioimmunoassay in intact male goats as well as in prepubertally castrated goats injected daily, for 2 weeks, with oil vehicle and then, for 4 weeks, with testosterone propionate in oil to study the influence of gonadal steroids on posterior pituitary hormones. Packed cell volume, plasma osmolality and sodium concentration were also measured in all blood samples. Plasma levels of oxytocin, vasopressin and cortisol were similar in the intact and oil-injected castrated goats. Testosterone treatment significantly increased plasma levels of oxytocin (P less than 0.01) in castrated goats but the increased levels were similar to those seen in the intact goats at the same time of year. Plasma levels of cortisol and vasopressin were unaffected by testosterone propionate treatment, whereas packed cell volume was significantly decreased (P less than 0.01). Testosterone treatment of castrated male goats appears not to have any action on pituitary hormones and oxytocin increases in the spring in both intact and castrated male goats.

Animals↗
PubMed1988

Endogenous opioid actions and effects of environmental disturbance on parturition and oxytocin secretion in rats.

Blood samples were taken from conscious, chronically-catheterized rats during parturition for measurement of oxytocin by specific radioimmunoassay. After the birth of the 3rd pup, rats were allowed to remain in their nesting cage (undisturbed rats) or were transferred for 45 min to a glass bowl (disturbed rats); at the time of transfer, rats were given an i.v. injection of the opioid antagonist naloxone or saline vehicle. Subsequent parturition was prolonged in saline-treated disturbed rats, but not in naloxone-treated disturbed rats. Parturition was significantly hastened in naloxone-treated undisturbed rats. Naloxone injections were followed by a large rise in plasma oxytocin concentrations in disturbed and undisturbed rats. We conclude, from a statistical analysis of the relationship within experimental groups between plasma oxytocin concentration and speed of parturition, that the effects of disturbance and of naloxone upon parturition may be accounted for, at least in part, by their effects upon oxytocin release. However, the effects of disturbance on parturition may not be mediated entirely by activation of opioid pathways. Naloxone did not potentiate oxytocin release in non-pregnant rats, or on Day 1 post partum, but did potentiate oxytocin release on Day 22 of pregnancy even in rats before the onset of parturition. Endogenous opioid pathways regulating oxytocin release therefore appear to be active during late pregnancy and during parturition itself.

Animals↗
PubMed1988

Percutaneous balloon aortic valvuloplasty in pregnancy.

Severe symptomatic aortic stenosis in pregnancy carries a poor prognosis. Although cardiopulmonary bypass and surgical repair has been reported to have a low maternal mortality, the fetal risk remains substantial. We report a case in which percutaneous balloon valvuloplasty was performed successfully at 19 weeks' gestation. The procedure restored physiologic left ventricular outflow and improved the aortic valve peak systolic pressure gradient. This allowed progression of the pregnancy to term and an uneventful delivery of a healthy infant, with no maternal complications. Although the long-term efficacy of percutaneous balloon aortic valvuloplasty has not been established, this case report has shown it to be useful as a palliative procedure.

Adolescent↗
PubMed1987

Using a national register for the epidemiological study of congenital heart defects.

Data validity is a fundamental problem in epidemiology. An objective of birth defect registers is the collection of high quality data, often from a number of sources, for use in epidemiological research. This paper examines the use of data from a national register in New Zealand in the study of congenital heart defects. The prevalence rates of congenital heart defects are shown to depend on the definition of the terms employed, the methods and completeness of the case ascertainment, the correctness of the diagnoses, the nature and size of the population under study, and the duration of followup. Recommendations are made for increasing the utility of this register in the study of this major group of malformations.

Autopsy↗
PubMed1987

Stress-induced disruption of parturition in the rat may be mediated by endogenous opioids.

Plasma samples were obtained before and during parturition from conscious rats implanted chronically with a jugular cannula. Rats were either allowed to remain in their nesting cage throughout parturition, or were moved immediately following the birth of the second or third pup into an empty glass chamber. The time-course of parturition was prolonged for mother rats which were moved in mid-parturition to this unfamiliar environment. However, in rats given an i.v. injection of the opioid antagonist naloxone at the time of transfer, parturition followed a normal time-course, and plasma oxytocin levels were significantly higher than in animals injected with saline. Thus our hypothesis is that stress activates opioid pathways which delay parturition by inhibiting oxytocin release. Opioid-mediated mechanisms may similarly be responsible for some problems in human parturition.

Animals↗
PubMed1987

Unity for education.

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Attitude of Health Personnel↗
PubMed1986

Remission of diarrhoea due to cryptosporidiosis in an immunodeficient child treated with hyperimmune bovine colostrum.

A boy aged 6 months who presented with poor weight gain, diarrhoea, and infection with Pneumocystis carinii was found to have congenital hypogammaglobulinaemia, which did not improve despite monthly treatment with intravenous gammaglobulin. At the age of 3 years and 2 months he developed severe vomiting and diarrhoea due to cryptosporidiosis, which failed to respond to conventional treatment. Infusion of hyperimmune bovine colostrum produced against parasite antigen, given by nasogastric tube, was started after symptoms had persisted for three weeks. His vomiting and diarrhoea resolved within five days of treatment, and oocysts were no longer seen in the stools after eight days. Later, however, he developed a rare complication, and oocysts were found in the common bile duct. Hyperimmune bovine colostrum may be useful in the treatment of many patients with immunodeficiency disorders.

Agammaglobulinemia↗
PubMed1986

Hypogonadism in chronic liver disease: impaired release of luteinising hormone.

Alcohol abuse leads to impotence, infertility, and feminisation. Patients with chronic alcoholism may have impaired hypothalamic-pituitary function. The release of luteinising hormone was investigated in men with alcoholic cirrhosis with and without hypogonadism and controls. Blood was sampled every 15 minutes for six or eight hours and luteinising hormone concentrations measured by radioimmunoassay. Data were analysed by iterative computerised analysis and spectral analysis to assess pulsatile release and the length of the cycle, respectively. Pulsatile release of luteinising hormone was shown in all the control subjects; in the men with alcoholic liver disease it was normal in those with subclinical primary testicular failure but absent or grossly attenuated in those with overt combined central and primary gonadal failure. The impaired release of luteinising hormone in the men with overt gonadal failure might be due to a hypothalamic defect.

Adult↗
PubMed1986

LH pulsatility following acute ethanol ingestion in men.

Alcohol abuse leads to impotence, infertility and feminisation. Patients with chronic alcoholism have impaired hypothalamic-pituitary function, but the effect of acute alcohol intake on hypothalamic function is unclear. The present study investigated the effect of ethanol ingestion on the pulsatile release of LH. Eight healthy male volunteers, aged 24-36 years, were investigated on a control day and a study day. Blood was sampled every 15 min for 8 h. On the study day ethanol was ingested, 1.5 ml/kg as an initial dose with supplements to maintain mean levels at 110-140 mg%. LH was measured on each sample by specific radioimmunoassay. Testosterone was measured at 0, 90 and 360 min. Data were analysed for pulsatile release by visual inspection, iterative computerized analysis and for longer period secretion by spectral analysis. Pulsatile release of LH was shown for all subjects on both days. Ethanol increased median LH levels (4.8 vs 5.55), but not by a significant amount. LH pulse amplitude was increased by ethanol ingestion, 3.7 vs 5.4 IU/l; P less than 0.05. Spectral analysis demonstrated a release of LH with a wavelength of 240 min which was unchanged by ethanol administration. Testosterone levels were unchanged.

Adult↗