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Biomedical subjects

M Morris

Publications and source records attributed to M Morris.

At least 415 records · Page 23Linked to original sources
PubMed1982

Cerebrospinal fluid vasopressin and oxytocin: evidence for an osmotic response.

A push-pull perfusion technique was used to sample third ventricular cerebrospinal fluid (CSF) in the conscious rat. Ventricular perfusate contained significant quantities of vasopressin and oxytocin, 13.1 and 4.5 pg/ml, respectively. Vasopressin and oxytocin levels were stable over a 3 h perfusion period. High sodium artificial CSF elicited a 4-5-fold stimulation of perfusate concentrations of both peptides. These findings suggest that the CSF represents a dynamic compartment in terms of neuroendocrine function.

Animals↗
PubMed1982

Response to pneumococcal vaccination in children with nephrotic syndrome.

Serologic responses to a 14-valent pneumococcal vaccine were measured in 20 children with steroid-responsive idiopathic nephrotic syndrome. All patients were free of proteinuria and receiving either daily (five patients) or alternate-day (15 patients) prednisone in a dosage of 1-2 mg/kg/day at the time of vaccination. Patients on alternate-day steroids received the vaccine on a day prednisone was not given. The mean fold rise in antibody titer was found to be normal in these children when antibody levels measured 3-6 wk post-vaccination were compared to prevaccination levels. This serologic response has correlated well with a 3-yr follow-up of the patients, none of whom has developed peritonitis secondary to any pneumococcal types in the vaccine. Also described are three patients who developed pneumococcal peritonitis during this period despite prior vaccination; in two of these patients, the pneumococcal type was not included in the vaccine (types 6b and 10a) and in one patient the organism was not typed. It is concluded that in children with nephrotic syndrome pneumococcal vaccination confers good protection against types included in the vaccine despite the concomitant administration of steroids. However, the patients who developed peritonitis secondary to other pneumococcal types remind us that pneumococcus must still be considered as an etiologic agent for peritonitis in nephrotic children who have been vaccinated.

Adolescent↗
PubMed1982

Government and voluntary agency relationships.

The concept of "voluntary agency" is being radically but almost imperceptibly revised under the press of events in the world of social welfare organization and finance. The term now embraces traditional nonprofit social agencies, proprietary agencies offering similar services often financed by the public sector, social programs financed by industry for its employees, and the family as a primary service provider. This evolution demands a major reconsideration of the new relationship between government and the voluntary agency.

Government↗
PubMed1982

Inhibition of the bronchial response to respiratory heat exchange by increasing doses of terbutaline sulphate.

Ten asthmatic patients inhaled terbutaline sulphate (250, 500, or 1000 micrograms) or placebo on separate days, double blind and in random order, 30 minutes before isocapnic hyperventilation induced by cold air inhaled in doses that increased in a precisely controlled manner. The respiratory heat exchange (RHE) was calculated for each level of ventilation and the results were expressed as the RHE causing a fall in FEV1 of 10% (PD10RHE). The PD10RHE after placebo was highly reproducible. After terbutaline inhalation there was a highly significant shift in the RHE dose-response curves to the right and a trend towards a linear increase in PD10RHE with increasing doses of terbutaline. The subjects who were most responsive to the RHE required more terbutaline to inhibit the response completely. The results indicate that RHE dose-response curves are a precise method to examine the effects of drugs on hyperventilation-induced asthma, that increasing doses of terbutaline can produce increasing protection, and that the degree of protection is dependent on the level of increased bronchial responsiveness to RHE.

Adult↗
PubMed1982

Developmental aspects of pituitary and adrenal responses to arterial hypotension in neonatal, weanling, and adult sheep.

We have studied neuroendocrine and heart rate responses to arterial hypotension in unanesthetized, chronically cannulated neonatal (less than 10 days old), weanling (3- to 4-wk-old), and adult sheep. Nitroprusside-induced arterial hypotension in the absence of hypovolemia promptly increased plasma ACTH, vasopressin (AVP), and cortisol levels in all three groups. The integrated adenohypophyseal and neurohypophyseal responses to a standard hypotensive stimulus were similar at the three ages, suggesting that the functional development of the systems subserving these responses is complete by the immediate postnatal period. The integrated cortisol/ACTH ratio was greatest in the youngest animals, suggesting that enhanced adrenal responsiveness to ACTH exists in neonatal as well as in late-gestation fetal lambs. The reflex tachycardia accompanying the arterial hypotension in the weanling and adult sheep was absent in the neonates.

Adrenal Glands↗
PubMed1982

Lipoprotein and blood pressure changes during weight reduction at Duke's Dietary Rehabilitation Clinic.

The influence of a weight-reducing diet among 129 obese patients after only 4 weeks at Duke's Dietary Rehabilitation Clinic is evaluated in its effect on cholesterol, HDL and LDL cholesterol, and on hypertension in combination with and without drugs. The 700-cal diet consists of 60 g protein, 60 g carbohydrates and 25 g invisible fat. After 4 weeks, total cholesterol decreased on the average by 44 mg% and serum triglycerides by 65 mg%. While LDL cholesterol declined by 30 mg% and VLDL cholesterol by 10 mg%, HDL cholesterol showed a small decrease of 7 mg%. Blood pressure levels were normalized in the 63 hypertensive patients. The conclusion is that a very moderate weight loss of only 9-12 kg has profound influences on important risk factors.

Adult↗
PubMed1982

Asthma induced by cold air and its relation to nonspecific bronchial responsiveness to methacholine.

We compared bronchial responsiveness to isocapnic hyperventilation of cold dry air at -18 degrees C and 0% humidity with bronchial responsiveness to inhaled methacholine in 24 subjects with current or previous asthma and 2 nonasthmatics. Two inhalation tests with each agent were carried out in random order on 4 consecutive days. The response to cold air was expressed as the respiratory heat exchange required to reduce the FEV1 by 10% (PD10 RHE) and the response to methacholine as the provocation concentration required to reduce the FEV1 by 20% (PC20 methacholine). There was a close positive linear correlation between PD10 RHE and PC20 (r = 0.86, p less than 0.001). The responsiveness to each agent was highly reproducible. The PD10 RHE could be measured in all 21 subjects with current symptoms of asthma and it could be obtained by extrapolation in 2 normal subjects, but it could not be measured in 3 subjects with a past history of asthma. The PC20 in the current asthmatics was 6.3 mg/ml or less, in the 2 nonasthmatic subjects, it was 14 and 16 mg/ml, and in the previous asthmatics it was between 26 and 54 mg/ml. The results indicate that nonspecific bronchial responsiveness is an important factor influencing the bronchial response to cold air, that either cold air or methacholine are suitable stimuli to measure nonspecific bronchial responsiveness, and that the differences in bronchial responsiveness observed between asthmatics and nonasthmatic subjects are in keeping with a quantitative rather than a qualitative difference in responsiveness.

Adult↗
PubMed1981

Central neural peptides and catecholamines in spontaneous and DOCA/salt hypertension.

Hypothalamic and neurophypophyseal levels of catecholamines and peptides were measured in spontaneous and deoxycorticosterone (DOCA)/salt hypertension. Catecholamines, norepinephrine, epinephrine and dopamine were measured by electrochemical detection while the peptides, vasopressin, oxytocin, luteinizing hormone-releasing hormone (LHRH), the enkephalins and somatostatin (SRIF) were measured by radioimmunoassay. Blood pressure was significantly elevated in both groups as compared to their controls. Marked changes in central neural peptides were observed in the SHR, while no differences were seen in DOCA/salt hypertension. Hypothalamic vasopressin, oxytocin, LHRH and SRIF were significantly decreased. In the posterior pituitary, enkephalins were increased twofold in the SHR. With regard to catecholamines, there was no change in hypothalamic content. However, a dramatic decrease in neurohypophyseal dopamine was observed in SHR. Plasma levels of vasopressin were significantly elevated in both types of hypertension while oxytocin was increased only in the DOCA/salt model. These result show that (1) a wide spectrum of neuroendocrine changes are associated with genetic hypertension, (2) there are CNS differences between DOCA/salt and spontaneous hypertension, and (3) central aminergic changes may be involved in th neuroendocrine alterations seen in the SHR.

Animals↗
PubMed1981

Hemorrhage in newborn lambs: effects on arterial blood pressure, ACTH, cortisol, and vasopressin.

Arterial blood pressure, central venous pressure, and plasma concentrations of ACTH, cortisol, and vasopressin (AVP) were monitored in chronically prepared, unanesthetized newborn and weanling lambs at rest and during and after hemorrhage of 15% of estimated blood volume at 1.5%/min. Differences in the endocrine and blood pressure responses to hypovolemia were noted in the two groups of animals. Hemorrhage did not change arterial mean pressure, reduced central venous pressure, and caused a delayed increase in the plasma concentrations of ACTH, cortisol, and AVP in the newborn lambs. In weanling lambs, hemorrhage reduced arterial mean pressure and central venous pressure and promptly increased plasma ACTH and cortisol levels while plasma AVP concentrations again showed a delayed increase. The data indicate that certain hormonal mechanisms for the defense of blood volume are present and operational within 3 days of birth and that age-related differences in the responses to hemorrhage exist in the lamb.

Adrenocorticotropic Hormone↗
PubMed1981

Ontogeny of endocrine (ACTH, vasopressin, cortisol) responses to hypotension in lamb fetuses.

We studied the ACTH, vasopressin (AVP), and cortisol responses to nitroprusside-induced hypotension in 27 chronically cannulated lamb fetuses between 0.53 and 0.98 gestation. Age-related differences in the hormonal responses to hypotension were found. Hypotension was associated with peak AVP levels of 7.8 +/- 2.7 pg/ml (mean +/- SE) in animals less than 0.68 gestation and 63.5 +/- 20 pg/ml in animals 0.89-0.98 gestation (P less than 0.05). The peak ACTH response was 95 +/- 20 pg/ml in the youngest animals and 380 +/- 111 pg/ml in animals 0.83-0.88 gestation (P less than 0.05). These observations suggest that maturation of the systems (possibly neuroendocrine) subserving the hormonal responses occurs in utero. Fetal plasma cortisol levels did not increase in response to the increase in ACTH except in animals 0.89-0.98 gestation. At this time, the basal plasma cortisol levels were high (58.8 +/- 16.8 pg/ml) and the ACTH response to hypotension was attenuated. Taken together, these findings suggest functional negative feedback regulation of ACTH by cortisol in the late gestation fetus.

Adrenocorticotropic Hormone↗