[The local anesthetics].
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Biomedical subjects
Publications and source records attributed to F Chardon.
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Pharmacokinetic measurements, neuroendocrine responses, and side effects profiles of intravenous infusions of 20 mg citalopram over 30 minutes during the early afternoon have been studied. Eight healthy male volunteers were enrolled in a placebo- (saline) controlled, single-blind, cross-over protocol. Plasma concentrations of the parent compound showed a double exponential decay. Demethyl and didemethyl metabolites were not detectable, but low concentrations of the propionic acid derivative of citalopram were found. Determination of the citalopram enantiomers yielded a balanced S(+)/R(-) ratio of 0.9 to 1.2. The endocrine response to the drug was characterized by significant increases in plasma prolactin and cortisol. Except for one subject, who developed pronounced side effects, human growth hormone showed a surge following saline that was inhibited following citalopram. Rectal temperature and heart rate were not affected and tolerability was favorable. Because of citalopram's extremely high selectivity for the presynaptic 5-hydroxytryptamine nerve terminals, the present data suggest that it might be a promising tool for the investigation of serotonergic function in the human brain in vivo.
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Differences and similarities in the temporal organization of hormone secretion in plasma reflect the activity of CNS pacemakers. One aspect of this activity, the temporal synchronization of the secretion of different hormones is still poorly understood. We report the analysis of melatonin and testosterone plasma concentrations during two nights in 6 normal healthy young men. Blood was collected every 20 min between 2040 and 0640. Plasma testosterone concentrations increased by 1.5- to 2-fold during the second part of the night, and melatonin by 2.5- to 4-fold. In each subject, the individual temporal pattern of melatonin was quite stable over the two nights of sampling, while testosterone profiles showed fluctuations. There was a high degree of parallelism in these two hormones nocturnal secretion. These results, together with previous studies, suggest that melatonin might entrain the nocturnal secretion of testosterone.
In order to analyse the role of hypercarotenemia in amenorrhoea, we have studied the ovarian function of 20 patients presenting with hypercarotenemia (serum carotene greater than 5 mumol/l). 12 of these were complaining of secondary amenorrhoea (group I), 7 with a normal weight (group I A) and 5 with a weight below 85% of ideal weight (group I B). Another group of 8 patients had normal menstrual cycles and a body weight within normal limits (group II). Group I presented an ovarian insufficiency of hypothalamic origin with an increase in the FSH/LH ratio. The patients in group I A although of normal weight differed from group II by a history of important weight variations, strenuous sports activity and an essentially vegetarian diet, the most likely reason for their hypercarotenemia. The high carotene levels however do not seem to be directly responsible for the amenorrhoea, in view of the normal menstrual cycles of the patients in group II. Hypercarotenemia can be considered as a biologic marker of weight loss with fat mobilisation and low T3 levels. It can also be due to a vegetarian diet. The latter may be an aetiological factor in anovulation by increasing faecal excretion of oestrogens and thus decreasing blood levels of oestradiol particularly when associated with other compounding factors such as excessive physical activity, loss of weight or affective problems.
The aim of this review of the literature is to indicate several characteristics of undesirable drug-induced psychiatric side effects and give a non-exclusive list of the responsible agents. For more detailed information and to facilitate the identification of iatrogenic effects, the clinician can consult available manuals, computerized data banks or specialists from pharmacological control centers.
Mammography is a basic examination which must never be dissociated from the clinical background. A statistical blind study of 330 cases shows that only well definite syndroms are reliable. The presence of absence of a single sign has no value. Difficulties arise in the diagnosis of suspect nodule in a dense dystrophic breast. Hydratation of the connecting tissue is a fundamental concept for analysis of mammographic pictures. The densities change according to hormonal influence, growth of dystrophy and specific signs of fibrillary or hyalin fibrosis. A histological study of serial cuts of the breast shows that the must reliable signs are found in the center of the nodule ande immediately around it. As in the histological study, serial cuts are indispensable in X-ray examination. Tomography improves the examination of dystrophies.
The authors present the first results of a new technique of breast examination: tomo-mammography. This new method allows a complete study of the whole gland without any compression and any modification of histological and anatomical structures, and an analysis of the center of breast lesions in which are rassembled the most reliable radiological signs. These first results enable to hope a large increase of possibilities of diagnosis of breast lesions in the most difficult anatomical and clinical cases.
The authors present first correlations between histology, anatomy and serial radiography of the breast, in order to establish a new understanding of the mammographic picture, with respect to the tridimensional histological structures. Several essential points are considered: - Mammographic pictures only show fibrous, connecting and fatty tissues. The epithelium of the galactophores is not shown, because of its low radio-opacity. Mammographic densities are due above all to fibrous connecting tissue, which has a high percentage of water. Benign or malignant breast tumors present with a proliferation of epithelium and connecting tissue, but only connecting tissue, more or less hydrated is shown on the mammographic picture. Many mammographic patterns are related to various superimposed fibrous strands, appearing as pseudotumoral opacities. The benign or malignant tumoral opacities are hidden or modified by multiple superimposed adjacent structures. - The mammographic patterns is related to the degree of hydratation and components of the connecting tissue.