Biomedical subjects
Publications and source records attributed to C Arnaud.
Serum immunoreactive parathyroid hormone(IPTH) is normal in patients with X-linked hypophosphatemic rickets who are not treated with phosphate salts. Phosphate raises IPTH in these patients. Endogenous IPTH does not influence the existing defect in tubular reabsorption of phosphate in male patients.
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The infusion of thyrocalcitonin (TCT) into thyroparathyroidectomized rats, given either no exogenous parathyroid hormone or a constant infusion of this hormone, leads to a transient phosphaturia and a decreased excretion of urinary magnesium, calcium, and hydroxyproline without a change in glomerular filtration rate. The changes in phosphate excretion may be due to a direct effect of the hormone upon renal tubular function or they may be a consequence of the fall in plasma calcium brought about by the action of TCT upon bone. In support of this latter alternative is the fact that the infusion of sodium ethylenebis-oxyethylenenitrilotetraäcetic acid (EGTA, a specific chelator of calcium) also leads to phosphaturia presumably as a consequence of hypocalcemia. However, EGTA infusion leads to enhanced urinary hydroxyproline excretion and sustained phosphaturia. These latter observations are interpreted to mean that alterations in the local ionic environment of osteolytic cells lead to changes in their activity and constitute a local regulatory system whose activity is modulated by the hormones, thyrocalcitonin and parathyroid hormone.
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The reactivity of the somesthetic S1 cortex was studied in the rat, in the course of the seven principle stages of the sleep-waking cycle, in terms of the variation in amplitude of positive wave 4 of the evoked potential induced by stimulation of the thalamocortical radiations. The amplitude of positive wave 4 is minimal during waking with theta (attentive and/or active). It increases in the course of waking without theta, to reach its maximum during the stage of sleep with slow waves. The amplitude decreases with the deepening of slow sleep (spindles, intermediate stage) to a level near to waking without theta, during rapid sleep. No significant difference is observed during periods of eye movements bursts. The variability of the amplitude of intra-state responses is lowest in the phases of waking and paradoxical sleep. The recovery cycle of the S1 cortex responses is long (several hundreds of milliseconds). The rate of recovery is inversely proportional to the amplitude of the response to the conditioning stimulus. It is therefore higher during waking and rapid sleep than during the different stages of slow sleep. These results are integrated in the neurophysiological data of sleep in the rat.
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The authors present a method of real-time automatic analysis of the sleep-waking cycle in the rat recorded by a miniature telemetry system. This method detects seven behavioural phases second by second. The correspondance computer-corrector is 88 p. 100 for the three principal phases: waking, slow sleep and paradoxical sleep.
We examined lens autofluorescence and the permeability of the blood-retinal barrier in 56 diabetic patients (34 insulin-dependent and 22 non-insulin-dependent), using the Fluorotron Master (R), a commercially available fluorophotometer. Significant relationships were found between age and lens autofluorescence (p < 0.01), between duration of diabetes and lens autofluorescence in insulin-dependent diabetics (p < 0.01), and between duration of diabetes and blood-retinal barrier permeability in all diabetics (p < 0.05). The relationships between lens autofluorescence and duration of diabetes in non-insulin dependent patients (p > 0.05), and between lens autofluorescence or the penetration ratio and HBA Ic during the five preceding years (p > 0.05) were not significant. Fluorophotometry provides an objective and reproducible method for in vivo investigation of the ocular complications of diabetes and of the factors influencing them.
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It may be difficult to differentiate between cells of parathyroid and thyroid origin in ultrasound-guided fine needle aspirations of the neck region, even in patients with a clinical history of hyperparathyroidism. A parathyroid hormone antibody was used in an immunohistochemical system to confirm a parathyroid origin in fine needle aspirate smears from nine patients with hyperparathyroidism. Immunoperoxidase positivity for parathyroid hormone confirmed a parathyroid origin in six of nine cases and was strongly suggestive, although equivocal, in the remaining three cases. Technical problems included nonuniform staining and background staining.
Distribution and correlations of serum uric-acid, cholesterol, triglycerides and lipoproteins were sought in this paper. Blood triglycerides and blood cholesterol in males were found significantly higher in patients with hyperuricaemia than in normo-uricaemic subjects. This elevation was reflected in the electrophoresis by a significant elevation of the bêta and pre-bêta lipoproteins correlated with hyperuricaemia. Partial correlations between age and serum uric-acid have been also demonstrated.
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