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M Oates

Publications and source records attributed to M Oates.

12 recordsLinked to original sources
PubMed2000

Chronic leptin administration in developing rats reduces stress responsiveness partly through changes in maternal behavior.

In adult rodents, leptin has been shown to significantly alter the activity of several neuroendocrine functions, including the activity of the hypothalamic-pituitary-adrenal (HPA) axis. Leptin is generally believed to be inhibitory to HPA activity in adults. Developing rat pups have high circulating levels of leptin, which begs the question of leptin's physiological role in controlling basal and stress-induced adrenocortical activity in neonatal rats. In this study, we treated rat pups daily from days 2-9 (or 6-10) of life with either vehicle or leptin (1 or 3 mg/kg body wt, ip) and determined the effects on body weight gain, fat pad deposits, and HPA activity in 10-day-old pups. We measured hypothalamic CRF mRNA levels in vehicle- and leptin-treated pups by in situ hybridization and determined plasma ACTH, corticosterone, and leptin concentrations under basal conditions or following exposure to a 3-min ether stress. Because leptin activates sympathetic activity and energy expenditure in adults and possibly also in rat pups, and because litter temperature is an important determinant of maternal behavior, we also investigated whether chronic leptin administration would modify aspects of maternal care that are important for the maintenance of HPA function. Chronic leptin treatment increased circulating levels of leptin and had significant dose-related metabolic effects, including reduced body weight gain and fat pad weight in 10-day-old pups. Basal expression of CRF mRNA in the PVN or secretion of ACTH and corticosterone was not modified by leptin treatment. In contrast, chronically elevated leptin concentrations during the neonatal period significantly lowered CRF expression in the PVN 60 min after stress and reduced the duration of the ACTH response to stress in pups, suggesting that glucocorticoid feedback on the HPA axis might be altered by this treatment. In addition, mothers caring for pups injected with leptin displayed longer bouts of anogenital licking of pups than mothers of vehicle-treated rats. Given that this particular type of pup stimulation has been shown to influence stress responsiveness, it is possible that the maternal response modulates the effects of exogenous leptin treatment. In conclusion, our results demonstrate that the leptin signal is functional during the early developmental period and that leptin can modulate the hormonal response to stress in young rats either by a direct effect on the HPA axis or indirectly through changing some aspects of maternal behavior.

Adipose Tissue↗
PubMed1994

Topoisomerase I and II activity in human breast, cervix, lung and colon cancer.

The identification of human DNA topoisomerases as cellular targets for active anti-cancer drugs has stimulated further interest in topoisomerase function in tumour biology. Topoisomerase I and II catalytic activity is detectable in many normal and malignant tissues. However, little is known about the expression of topoisomerases in most human solid tumours. The present study evaluated topoisomerase I and II activity in biopsy samples from 86 patients with breast, lung, cervix or colon cancers. Significant intra- and inter-tumour variation in topoisomerase expression was observed. Topoisomerase I activity was relatively high in cervix and colon tumours in comparison to lung and breast cancers. Topoisomerase II activity was high in cervix, colon and lung cancers relative to breast cancer. Topoisomerase I and II activity co-segregated in individual colon tumour samples, but no correlation was observed in cervix, lung or breast tumours. The large heterogeneity in both topoisomerase I and II activity within a tumour type suggests a mechanism for variable response to topoisomerase-directed therapy. The differences in activity between tumour groups suggest that the potential efficacy of inhibitors of topoisomerase I in colon and cervical tumours may be greater than in lung and breast tumours. Future in vivo evaluation is required to establish the clinical relevance of the observed heterogeneity in topoisomerase activity.

Breast Neoplasms↗
PubMed1994

Cardiac MRI.

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Angiocardiography↗
PubMed1990

Prepartum psychosis.

Four patients are described who suffered from postpartum psychosis, and also from similar episodes starting in late pregnancy. It is argued that these patients provide evidence for the prepartum onset of postpartum psychosis in a small minority of patients. The relevance of this to the aetiology of puerperal psychosis is discussed.

Adult↗
PubMed1989

Normal emotional changes in pregnancy and the puerperium.

There is tremendous individual variation in the response to the inherent emotional, psychological and cognitive changes that take place during pregnancy and puerperium, particularly in first-time mothers. Although the psychological changes, particularly in terms of emotional and behavioural changes, have probably been overstated in pregnancy, there are undoubtedly marked changes in such aspects of functioning following delivery. Women should be aware of these changes and be prepared for them, and obstetricians and midwives should incorporate them into their management of patients. All women have valid psychological needs during pregnancy and in the puerperium, and these must be met in order to ensure maternal and infant health and maximum satisfaction with the experience. Antenatal and postnatal care should not result in a struggle for power and control between patient and obstetrician. Emotional reassurance and support can only follow upon adequate information. The best antenatal care and management of delivery requires a spirit of mutual trust and active participation on the part of the patient in the decision-making process. There is ample evidence to support the theory that continuity of care and the continuous supporting role of the midwife, particularly during delivery, exerts a favourable outcome in mothers and children.

Adolescent↗