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Biomedical subjects

H Langevin

Publications and source records attributed to H Langevin.

14 recordsLinked to original sources
PubMed1987

Plasma atriopeptin concentrations in hyperthyroidism, euthyroidism, and hypothyroidism: studies in man and rat.

Atriopeptin (AP) is a polypeptide produced by atrial myocytes that is capable of inducing diuresis, natriuresis, and vasodilatation. Because thyroid dysfunction is known to be associated with alterations in both renal function and vasomotor control, we investigate the possible effects of varying thyroid function on AP in humans and rats. Plasma AP concentrations were determined in hyperthyroid and hypothyroid patients and normal subjects. Plasma AP was also measured in some patients after the iv infusion of 1 L 150 mmol/L NaCl and after treatment of hyperthyroidism or hypothyroidism. Plasma and atrial AP concentrations were measured in hyperthyroid, euthyroid, and hypothyroid rats. Plasma AP concentrations did not differ in the hyperthyroid (n = 22), euthyroid (n = 45), and hypothyroid (n = 16) subjects [47.1 +/- 18.2 (mean +/- SD), 45.1 +/- 28.9, and 42.4 +/- 20.0 pg/mL, respectively]. After NaCl infusion, mean plasma AP concentrations did not increase significantly in any of the three groups. Treatment of hyperthyroidism and hypothyroidism did not result in a significant change in plasma AP levels. In contrast, plasma AP concentrations were significantly higher in T4-treated (hyperthyroid) rats than in either euthyroid or propylthiouracil-treated (hypothyroid) rats [621 +/- 17 vs. 266 +/- 41 (P less than 0.01) and 210 +/- 28 pg/mL (P less than 0.001), respectively], whereas atrial AP contents were similar in the three groups of rats. We conclude that hyperthyroidism and hypothyroidism in man are not associated with significantly altered plasma AP concentrations. The higher plasma AP levels in T4-treated rats may reflect the relatively shorter duration or greater severity of thyroid dysfunction or thyroid hormone-induced myocardial hypertrophy in the animals.

Adult↗
PubMed1986

Anatomical localization of corticotropin-releasing activity in the human brain.

Corticotropin-releasing activity (CRa) and arginine-vasopressin (AVP) content were measured in seven human hypothalami. The hypothalami were obtained from routine autopsy of patients suffering from no obvious neuroendocrinological abnormality. Twelve distinct hypothalamic areas were dissected in the frozen state and extracted in aqueous solution. CRa was measured by a bioassay measuring the aCTH released by rat pituitary cells in vitro, and vasopressin by direct radioimmunoassay. CRa was detectable in almost every area with the highest values in the supraoptic, paraventricular and infundibular (arcuate) areas. Vasopressin concentrations were maximum in the supraoptic nucleus, followed by the paraventricular and infundibular nuclei. We conclude that: hypothalami obtained from routine autopsy at a general hospital can be used for consistent CRa and vasopressin assay. Vasopressin and CRa are similarly distributed in man and in the rat. In both species, high CRa, which is not explained by AVP, is found in the paraventricular nucleus. The infundibular (arcuate) nucleus seems to display non AVP-dependent CRa much greater in the human than in the rat.

Adrenocorticotropic Hormone↗
PubMed1984

Regional distribution of bombesin and seven other regulatory peptides in the human brain.

In order to compare within the same brains the quantitative distributions of a range of neuropeptides, bombesin, N- and C-terminal glucagon, cholecystokinin, neurotensin, somatostatin, substance P and vasoactive intestinal polypeptide immunoreactivities were determined by radioimmunoassay in 24 regions of 5 normal adult human brains. Each peptide showed a different distribution pattern. Of the peptides not previously mapped in detail in the human brain, bombesin-like immunoreactivity was present in all regions with the highest concentrations in particular areas of the hypothalamus, septal nuclei, nucleus accumbens, globus pallidus, amygdala, periaqueductal grey and substantia nigra. C- and N-terminal glucagon immunoreactivities were detected only in the ventromedial hypothalamus. The concentrations of the remaining 5 peptide immunoreactivities, and their molecular forms, were in good general agreement with those reported individually by others in both human brains and those of experimental animals. The quantitative mapping of the regulatory peptides in the human brain provides an essential base for further comparative study in diseased postmortem brains.

Adult↗
PubMed1982

Distribution of substance P, somatostatin and neurotensin in the human hypothalamus.

The distribution of substance P, somatostatin and neurotensin in the human hypothalamus was studied by radioimmunoassay analysis of 11 nuclei and areas within the hypothalamus, in 10 human post-mortem cases. The samples were microdissected according to a recently developed standardized method. Substance P was present in higher concentrations both rostrally in the hypothalamus, and ventrally. Somatostatin was found predominantly in the basal tuberal region, and neurotensin in the anterior hypothalamic area. The chromatographic behaviour of human hypothalamic neurotensin is also presented.

Adult↗
PubMed1982

[Home hyperalimentation through the digestive tract].

There are few reports in the contemporary literature on the use of home hyperalimentation by the enteral route, especitially for intestinally crippled patients. The authors describe five patients who had a total of 78 months of therapy by continuous nasogastric infusion of an elemental diet at home. The majority of the patients had undergone massive bowel resection. Home intravenous hyperalimentation techniques are compared with respect to feasibility, morbidity, cost and psychologic impact for the patient. Because of the differences, the authors suggest that home intravenous hyperalimentation should be reserved for patients who have failed a trial of enteral therapy.

Adult↗
PubMed1980

A new method for the microdissection of the human hypothalamus, with mapping of cholinergic, GABA and catecholamine systems in twelve nuclei and areas.

A new method was developed for the microdissection of the human hypothalamus, based on a local system of co-ordinates, using the fornix as an internal reference curve. Dopamine, noradrenaline, adrenaline, CAT, GAD and GABA were assayed in twelve microdissected nuclei and areas, in nine human post-mortem cases. This neurochemical study was aimed to demonstrate the validity of the dissection method, and its potential usefulness for the controlled study of groups of abnormal human cases.

Adolescent↗
PubMed1978

Corpora amylacea of the lumbar spinal cord and peripheral nervous system.

Tissue from L-4 spinal cord, dorsal root ganglia, sural nerve, and intramuscular branches to the gastrocnemius was obtained during 35 random autopsies, embedded in paraffin, and stained with PAS and Holmes Alcian blue and studied for the incidence and distribution of corpora amylacea (CA). Intraaxonal CA in spinal grey matter were commonly found, but the incidence in root ganglia, sural, and intramuscular nerve was low. Clinically insignificant intraneuronal spinal grey CA were found in six of eight men past the age of 60 years. Corpora amylacea in spinal white matter were most common in the region of posterior root entry.

Age Factors↗
PubMed1966

A psychiatric home care program: a report based on three years' experience (1962-1964).

The activities covering a three-year period of a psychiatric home care treatment program attached to a psychiatric unit of a general hospital are described. A detailed account of its operation and the roles played by each member of the team is given. This service frequently provides a substitute for hospitalization in the management of both acute and chronic psychiatric states and thereby constitutes an important preventive measure in the field of public health. Even if the initial attitude of the patient is negative it is possible to gain the co-operation of the family who become a useful ally in the treatment. The co-operation of the patient is not as essential as has been thought. The traditional role of the psychiatrist is reversed by virtue of his attending the patient at home. The active participation of social agencies is an integral part of the treatment.

Home Care Services↗