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M Hay

Publications and source records attributed to M Hay.

108 records · Page 6Linked to original sources

Effects of food deprivation on midbrain 5-HT1A autoreceptors in Lewis and SHR rats.

Food deprivation stimulates the activity of the hypothalamo-pituitary-adrenal axis and brain serotonin (5-hydroxytryptamine, 5-HT) synthesis. Because midbrain somato-dendritic 5-HT1A autoreceptors may obey homologous and heterologous (e.g. by glucocorticoids) down-regulation, we have analyzed whether 24 hr of fasting affects midbrain 5-HT1A receptor binding and sensitivity in Lewis and SHR rats (i.e. strains that differ in behavioral/neuroendocrine responses to stressors). Fasting affected neither [3H]8-hydroxy-2-(di-N-propylamino)tetralin ([3H]8-OH-DPAT) binding at 5-HT1A autoreceptors nor 8-OH-DPAT-induced inhibition of midbrain 5-HT synthesis (an index of 5-HT1A autoreceptor sensitivity). Because fasting increased 5-HT precursor (tryptophan) levels to similar extents in the midbrains of saline- and 8-OH-DPAT-treated rats, we conclude that food deprivation does not affect 5-HT1A autoreceptors. In turn, our results suggest that the differential effects of 5-HT1A receptor agonists on food intake, in fed and fasted rats may be independent from 5-HT1A autoreceptors.

5-Hydroxytryptophan↗

[Radiotherapy of stage T1-T2 M0 prostatic adenocarcinoma. Analysis of the carcinologic results of a multicenter study of 610 patients. Groupe Radiothérapie de la Commission de Coopération Médicale Intercentres (CCMI)].

PURPOSE: Retrospective analysis of the results of radiotherapy in localized prostatic adenocarcinoma. Complications were excluded. PATIENTS AND METHODS: Six-hundred-and-ten T1-T2 adenocarcinomas of the prostate were treated with continuous courses of external beam radiation therapy in 19 participating Institutes between January 1983 and January 1988. The mean follow-up was 10.4 years; the mean age of patients at the beginning of radiotherapy was 68.5 years. RESULTS: A 10-year, local control had been achieved in 86% of T1-T2 (81.4% for T2). The 5- and 10-year metastatic relapse rates were 25.3% and 30% (29% and 38.1% for T2), respectively. At 10 years, 62.4% of T1-T2 were recurrence-free; overall survival rate was 45.8% and cause-specific survival rate was 70.5%; 29.9% of T1-T2 patients were alive and disease-free. T category (TNM), pathologic grade, pelvic lymph node status, local tumor control, and obstructive ureteral symptoms were correlated with survival. The influence of pelvic nodes radiation, dose, overall treatment time, previous endocrine treatment, and transuretral resection was not significant for disease-free survival (alive and disease-free) and other endpoints. CONCLUSION: There was no difference between the French series (1975-1982 and 1983-1988). The results of the literature are comparable to ours. As far as prognostic factors are concerned, this report provides evidence that the explainable variables which influence survival depend on the tumor and patient status.

Adenocarcinoma↗

Area postrema and sympathetic nervous system effects of vasopressin and angiotensin II.

1. Precise control over the cardiovascular system requires the integration of both neural and humoral signals related to blood volume and blood pressure. Humoral signals interact with neural systems, modulating their control over the efferent mechanisms that ultimately determine the level of pressure and volume. 2. Peptide hormones such as angiotensin (Ang)II and arginine vasopressin (AVP) act through circumventricular organs (CVO) to influence cardiovascular regulation. 3. The area postrema (AP), a CVO in the brainstem, mediates at least some of the central actions of these peptides. Vasopressin appears to act in the AP to cause sympathoinhibition and a shift in baroreflex control of the sympathetic nervous system (SNS) to lower pressures. These effects of AVP and the AP appear to be mediated by alpha2-adrenoceptor and glutamatergic mechanisms in the nucleus tractus solitarius. 4. In contrast to AVP AngII has effects in the AP to blunt baroreflex control of heart rate and cause sympathoexcitation. The effects of chronic AngII to increase activity of the SNS may be due to AP-dependent activation of neurons in the rostral ventrolateral medulla.

Angiotensin II↗

Behavioural, growth and immune consequences of early weaning in one-week-old large-white piglets.

Genetic improvement in sows' prolificity is limited by their milk capacities, which do not allow all piglets to survive or grow normally. This experiment compared the behaviour, growth and immune responses of piglets that were weaned early at 6 days of age (EW) vs. control Large White piglets' (C) suckled by their mothers. Behaviour of 9 litters of 5 to 8 piglets in each group were observed from d5 to d20. All piglets were weighed from birth to d74. Three piglets from each group were slaughtered on d36 for immunological analysis. Until they began to eat dry food, EW piglets walked and vocalised more than C piglets. After that time, when resting, they were less often lying down and more frequently in contact with littermates under the heater. Aggressive behaviour and belly-nosing were more frequent. They displayed a more marked growth check after weaning than did C piglets until 28 days of age. In EW piglets, at 36 days of age, there was a higher density of T- and B-lymphocytes in the gut epithelium and lamina propria, fespectively, in relation to the size of lymphoid follicles of Peyer's patches. The results indicate great behavioural adaptation capacities of very early-weaned piglets, together with earlier maturation of their gut immune system.

Adaptation, Physiological↗

Urinary excretion of catecholamines, cortisol and their metabolites in Meishan and large white sows: validation as a non-invasive and integrative assessment of adrenocortical and sympathoadrenal axis activity.

Urinary free corticoids (cortisol and cortisone), catecholamines (norepinephrine or NE, epinephrine or E, dopamine or DA, and their O-methoxylated metabolites) as well as creatinine (Cr) were analysed in 42 spontaneously voided urine samples from Large White (LW, n = 20), Meishan (MS, n = 6), and LW x MS (F1, n = 16) lactating sows. The cortisol concentration in the urine of MS (28.1 pg/micrograms Cr) was five-fold greater than that of LW sows (6.2 pg/micrograms Cr, P < 10(-4)). F1 were intermediate (12.0 pg/micrograms Cr). Mean cortisone concentration was also larger in MS (13.5 pg/micrograms Cr) compared to LW (7.1 pg/micrograms Cr, P < 0.01). Although the differences were less pronounced, the concentrations of the catecholamines were also greater in MS than in LW sows (norepinephrine: 25.4 versus 5.9 pg/micrograms Cr, epinephrine: 8.7 versus 2.8 pg/micrograms Cr and dopamine: 59.2 versus 17.8 pg/micrograms Cr, P < 10(-4)). These results confirmed the hypercortisolism state of MS pigs previously shown by plasma cortisol assay and supported the hypothesis that the sympathetic nervous system is hyperactive in this breed. These urinary investigations may offer possible applications for the assessment of chronic stress.

Adrenal Cortex↗