Biomedical subjects
Publications and source records attributed to C Burlet.
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The neuropeptide binding sites at the level of their target cells can be localized by several morphological methods. For one of the neurohypophysial hormones, vasopressin, not all labelling techniques can be applied: radioiodinated vasopressin has no biological activity; only 3Hvasopressin can be used. Immunocytochemical evidence for vasopressin receptors must be supported by complementary data in order to demonstrate the specificity of the binding. A new labelled ligand is prepared: vasopressin-dextran. In vivo, this macromolecular compound has antidiuretic properties equivalent to those of free vasopressin. In vitro, it gives a cross reaction with specific anti-vasopressin antibodies. For the same macromolecular compound, the ratio between the conjugated vasopressin estimated through R.I.A. and that assayed by biological method was 30.
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Ultrastructural examination of the posterior pituitary of the garden dormouse (Eliomys quercinus L) was carried out at different times in the annual cycle of this hibernating rodent. Obvious differences between experimental groups have not been observed, and the results presented here must be considered as general features of the garden dormouse posterior pituitary. Neurosecretory axons and endings can be divided into two types, according to different aspects of neurosecretory granules (NSG) and microvesicles (MV). One type contains spherical NSG with homogeneous cores and round MV. In the other type, NSG have various, often elongated, shapes. Their content shows two types of crystalline structures and most of the MV have flattened aspects. As it is very unlikely that this duality in NSG is a result of an artefact of fixation, three hypotheses are presented as explanation. The duality of NSG might be related either to their hormonal content (oxytocin or vasopressin) or to their degree of maturation. Moreover, both explanations may be valid. In the species studied, pituicytes often contain concentric lamellar structures of the endoplasmic reticulum (whorls), the significance of which remains obscure.
The administration of ehtanol by gavage immediately produced a maintened hyperdiuresis, a transient decrease of urinary osmolality and antidiuretic hormone secretion, followed by increased plasmatic and urinary antidiuretic hormone concentrations. Chronic intoxication enhanced these effects probably due to central disturbance.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
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We used the Amersham radioimmunological method to measure plasma 1 alpha 25-dihydroxyvitamin D3 (calcitriol) levels in patients presenting with one of the following diseases: (i) non-acute myelodysplastic syndrome (39 cases); (ii) acute myeloid leukaemia in blastic phase (43 cases) or in complete remission (15 cases) and (iii) acute lymphoid leukaemia in blastic phase (11 cases). All patients had normal metabolic functions. Compared with our standard laboratory values (15-35 pg/ml), the results of these assays were related to the type of pathology or, in patients with acute myeloid leukaemia, to the stage of the disease (p less than 0.001). Moreover, the mean plasma calcitriol values differed according to the type of pathology (p less than 0.003). Patients with acute myeloid leukaemia in blastic phase had a low level of calcitriol as compared with controls (p less than 0.05) and with patients with acute myeloid leukaemia in complete remission (p less than 0.001) whose calcitriol levels were never low. In contrast, there was no significant difference between controls and patients with myelodysplastic syndrome or acute lymphoid leukaemia in blastic phase. This study demonstrates the usefulness of plasma calcitriol assays in malignant blood diseases where low values in certain types of leukaemia would incite to include calcitriol in therapeutic regimens.
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Hormonal regulation of fluid and electrolyte homeostasis and blood pressure is under the auspices of three organs: the heart, the brain, and the kidneys. Their regulatory roles are fulfilled by the actions of atrial natriuretic peptide (ANP), vasopressin, and the renin-angiotensin-aldosterone system (RAAS), respectively. The aim of this study was to appreciate the short-term effects of orthotopic human heart transplantation on the release of these hormones. Alpha-ANP, renin, aldosterone, and vasopressin serum levels were assessed by radioimmunoassay before and during the 10 days after grafting in a series of 10 patients. On day 1, alpha-ANP levels dropped from 42.4 +/- 6.5 to 25.1 +/- 2.2 fmol/ml before returning to levels comparable with those found before transplantation. This decrease in alpha-ANP levels was associated with a peak in vasopressin and aldosterone levels. With the exception of the peak in vasopressin levels seen on day 1, preoperative and postoperative levels of this hormone were near normal. Increased preoperative renin levels dropped significantly as of day 5 (from 268 +/- 99 to 122 +/- 66 ng/L). This decrease was related to improved patient hemodynamic status. No significant correlation was found between the changes in alpha-ANP levels, RAAS or vasopressin levels, patient hemodynamic status, or administered drugs. In conclusion, grafted heart tissue was capable of high alpha-ANP release early on. The drop in alpha-ANP serum levels, compared with the peaks in vasopressin and aldosterone on day 1, might have been caused by the ability of the graft to play a role in the hormonal regulation of fluid and electrolyte balance.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this study was to investigate the changes in endocrine control of blood pressure and electrolyte homeostasis during the early postoperative period after heart transplantation. Dynamic testing using volume-expansion to increase cardiac filling pressures was performed to determine changes in alpha atrial natriuretic peptide, renin, aldosterone, and vasopressin secretion in response to a physiologic stimulus. Volume expansion was performed on five heart transplant patients each day from postoperative day 1 to postoperative day 5. Alpha atrial natriuretic peptide, renin, aldosterone, and vasopressin plasma levels were assessed by radioimmunoassay before and during the 6 hours after the beginning of infusion. No significant changes in the secretion of any of the various hormones studied were found after volume expansion. Moreover, we found that heart transplant recipients were unable to increase water and sodium renal excretion after volume expansion. The physiologic decrease in vasopressin release after volume expansion appears to be altered by graft denervation. Furthermore, persistently elevated alpha atrial natriuretic peptide plasma levels at rest despite improved patient hemodynamic status and the absence of enhanced hormone secretion after a physiologic stimulus are in favor of an intrinsic hypersecretion of this hormone. Moreover, the absence of an appropriate renal response could be a major consequence of both the lack of further increased alpha atrial natriuretic peptide secretion and the heart denervation resulting from transplantation. This blunted renal response should be taken into account when managing patients in the early period after transplantation.