Biomedical subjects
G Manciet
Publications and source records attributed to G Manciet.
Standard heparin but not LMW heparin induces a concomitant increase of t-PA and PAI-1 without modification of global fibrinolysis: study after 60 days treatment.
The relationship between heparin and fibrinolysis is strongly suggested. We have studied the influence on fibrinolysis of standard heparin (SH), Calciparin and low molecular weight heparin (LMWH), Fraxiparin, given preventively in an elderly population. Patients were randomized into two groups (SH, LMWH). We investigated fibrinolytic parameters (ECLT, t-PA antigen, PAI-1 activity and antigen, t-PA/PAI-1 complexes) before treatment (D0) and at D30 and D60, before and after venous occlusion (VO). Values at D0, D30 and D60 were compared within each group. A significant and marked increase in t-PA and t-PA/PAI-1 complexes at D30 and D60 before and after VO was noted only in the SH group. The mechanism and clinical relevance of this increase remains to be established.
Pharmacokinetics of the antidepressant tianeptine at steady state in the elderly.
The pharmacokinetics of tianeptine, an antidepressant with an original serotoninergic neurochemical action, was investigated in elderly patients. Kinetic profiles were developed in 12 elderly patients (age range: 72-81 yr) after single (12.5 mg) dose and multiple oral dosages (12.5 mg tid for 17 days). Multiple dosing of tianeptine was well tolerated; no accumulation of the unchanged drug was observed. Tianeptine and its MC5 metabolite (C5 acid analogue of tianeptine) reached maximum plasma levels after 1.81 +/- .99 and 2.96 +/- 1.44 hr, respectively, with values of 353 +/- 198 and 81 +/- 20 ng/mL, respectively, after a single dose and of 405 +/- 202 and 175 +/- 85 ng/mL, respectively, after multiple dosing. Minimum plasma concentrations of tianeptine were about half those of its MC5 metabolite (68 +/- 41 and 121 +/- 64 ng/mL-1 on day 5), and for each compound, they were not statistically different from day 5 to day 18 of the chronic administration. This finding is compatible with the terminal half-lives that were observed after the single dose that was 2.8 +/- .9 hr for tianeptine and 12.3 +/- 7 hr for the MC5 metabolite. For both compounds, the area-under-the-plasma levels time curve at steady state was as predicted from the initial single dose that showed no deviation from linearity with time. The kinetics of tianeptine in elderly patients were similar to those reported for young adults. However, MC5 metabolite plasma levels were higher in elderly patients than in younger patients.(ABSTRACT TRUNCATED AT 250 WORDS)
[Therapeutics and arterial aging. Antiaggregants].
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[Heparin and the arterial wall].
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[Indications and limitations of anticoagulant treatment in elderly patients].
Anticoagulants constitute the rational treatment of thromboembolic accidents occurring in elderly people, but they are often not prescribed because of the risk of haemorrhage. The chronological age by itself is not a contra-indication, the limitations being the diseases associated with ageing. Anticoagulants may be used as curative treatment in atrial fibrillation with dilated left atrium (greater than 45 mm at echocardiography), in myocardial infarction, embolic strokes and complicated arteritis. They may also be used as preventive and curative treatment in phlebitis and pulmonary embolism. The complications of anticoagulant therapy will be better prevented by using the international normalized ratio and by prescribing doses that are adequate for each indication.
[Value of the corticoliberine test in the etiologic diagnosis of Cushing's syndrome].
Several studies have demonstrated that the corticotropin-releasing factor test (CRF) is useful for the aetiological diagnosis of Cushing's syndrome: in Cushing's disease, as opposed to ectopic ACTH secretion syndrome, the hypothalamus-pituitary-adrenal (HPA) axis can still be stimulated by CRF. In the present study, we compared the CRF test with the reinforced dexamethasone suppression test in 18 patients: 11 with Cushing's disease, 6 with ectopic ACTH secretion and 1 with adrenal gland adenoma. We obtained 2 false-negative results with the CRF test and 1 false-positive result with the dexamethasone suppression test. Our study, together with published data, suggests that the CRF test is useful in the exploration of Cushing's syndromes of uncertain origin. However, the results obtained with this test must be compared with those of other methods used to explore the HPA axis and which are still necessary.
Low levels of serum thyroglobulin after withdrawal of thyroid suppression therapy in the follow up of differentiated thyroid carcinoma.
We evaluated the reliability of very low serum thyroglobulin (Tg) levels (less than 3 ng/ml) obtained after withdrawal of thyroid suppression therapy in 224 patients without anti-Tg antibodies, who had undergone total thyroidectomy (125 patients) or thyroidectomy followed by 1 or more courses of 131I therapy (99 patients), by performing whole body scans after a therapeutic course of 131I given at the same time of Tg measurement. In 79 patients (35%) a positive scan, associated with a very low level of Tg, was noted. The 131I uptake was limited to the thyroid bed in 60 patients, but metastases were demonstrated in 19 patients (8.5%). These results are mainly explained by the much improved performance of scintigraphy after administration of therapeutic doses of 131I. In the majority of patients, especially those whose 131I uptake was limited to the thyroid bed, further scans were negative. Therefore, in these cases, negative Tg values can generally be considered an early indication of satisfactory evolution. However, in 8.5% of all cases, very low Tg levels were associated with metastases. Thus the follow up of thyroid cancer should not rely only upon Tg determination, even after suppression therapy withdrawal.
[Hypothyroid neuropathy].
Two cases of polyneuropathy in patients with hypothyroidism are reported. In both cases, the polyneuropathy involved the lower limbs and was predominantly distal. It was sensorimotor in the first patient and purely sensory in the second one. Electrophysiological findings were consistent with an axonopathy. Symptoms and electrophysiological parameters improved with thyroid therapy. Neuropathy in such cases is probably related to the duration of hypothyroidism.
Antihypertensive efficacy and acceptability of rilmenidine in elderly hypertensive patients.
Elderly hypertensive patients (older than 70 years, with a diastolic blood pressure [BP] between 95 and 114 mm Hg) were entered into a study after a 2-week wash-out period and randomized to 2 parallel groups: rilmenidine (n = 28) and methyldopa (n = 30). The initial dose (rilmenidine, 1 mg once daily A.M. or methyldopa, 250 mg twice daily) was doubled (1 mg twice daily or 500 mg twice daily, respectively) on day 21 if supine diastolic BP remained greater than 90 mm Hg. After a 6-week treatment period (days 0 to 42, with weekly examinations), the effects of treatment withdrawal (day 42) were evaluated twice daily (days 43 to 45), with a final examination on day 49. Most of the 58 patients (70%) (aged 81.5 +/- 0.8 years) with a mean diastolic BP of 100.2 +/- 0.7 mm Hg remained treated with the initial dose in both groups. Efficacy in both groups was identical on day 42: decrease in systolic and diastolic BP of approximately 18 mm Hg, with 85% of patients having BP levels normalized (supine diastolic BP less than or equal to 90 mm Hg). Compared with the reference period, no increase in adverse effects was noted apart from a moderate dryness of mouth in 15% of patients in both groups; no orthostatic hypotension was observed.(ABSTRACT TRUNCATED AT 250 WORDS)
The electrophysiological effects of thyrotropin-releasing hormone are similar in human TSH- and prolactin-secreting pituitary cells.
We studied the electrophysiological properties of individually characterized TSH-secreting cells cultured from pituitary fragments surgically removed from three patients, two who had primary TSH-secreting adenomas and one who had chronic TSH hypersecretion (hyperplasia) secondary to primary hypothyroidism. The TSH-secreting cells were excitable and had calcium-dependent action potentials. More than 80% of the cells cultured from the two patients with TSH-secreting adenomas were spontaneously active, whereas fewer cells (20%) cultured from the hypothyroid patient were spontaneously active. TRH (50 nmol/L) induced a complex pattern of electrical changes. The initial response was transient hyperpolarization (activation of potassium conductance), followed by increased low amplitude voltage fluctuations occasionally leading to action potentials. These TRH-induced electrophysiological changes were similar to those reported in rat and human PRL-secreting adenoma cells. These results suggest that TRH may have an identical mode of action in tumoral PRL and TSH cells. In the cells from the hypothyroid patient, the initial response to TRH cells was similar, but the second phase response was greater. The findings that the cells cultured from these patients behaved differently with regard to their electrophysiological characteristics (action potentials) and responses to TRH may reflect the different clinical conditions from which they were derived.
[Hemorheological disorders in very old persons. Improvement with pentosan polysulfate. Effect on leukocyte and platelet metabolites of arachidonic acid].
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Thallium-201 imaging in the follow-up of differentiated thyroid carcinoma.
Since thallium-201 imaging has been reported as a potential means of follow-up of patients with differentiated thyroid carcinoma (DTC) during ongoing thyroid suppression therapy, the authors evaluated the diagnostic sensitivity of this procedure in 31 patients known to have metastases or local recurrence. Among 51 tumor sites 201TI imaging had a detection rate of 45% whereas 84% was noted for imaging with 131I administered in therapeutic doses. Thus, even though the effectiveness of the two radionuclides is not strictly comparable due to the difference in the administered doses, Thallium imaging cannot be recommended as the only modality for the follow-up of patients with DTC. Six of the eight tumor sites negative with 131I were positive with 201TI (especially metastatic cervico-mediastinal lymph nodes). So 201TI imaging may particularly be helpful in localizing metastases or recurrences in patients with a negative 131I scan and abnormal levels of serum thyroglobulin.
Hemorheological changes in elderly subjects--effect of pentosan polysulfate and possible role of leucocyte arachidonic acid metabolism.
The effects of pentosan polysulfate (PPS) on various hemorheological parameters were studied in a group of very elderly subjects in good general health. Alterations in blood viscosity and filterability were detected in these patients, without any concomitant changes in factors which are known to affect these parameters: notably hematocrit, fibrinogen and plasma lipid levels. The hemorheological abnormalities were considerably improved by twice daily treatment with 50 mg of PPS (i.m.). Apart from its anticoagulant activity, PPS has been shown to have an anti-inflammatory action. We were interested to investigate its effects on metabolism of exogenous arachidonic acid (AA) by both platelets and leucocytes. It is becoming increasingly recognized that metabolites of AA via the 5 LO pathway appear to play a role in inflammatory processes. In this study, PPS was found to inhibit leucocyte 5 LO activity. Reduction in the levels of these metabolites may therefore have an effect on whole blood rheology.
[Monitoring prolonged treatment with amiodarone in the elderly. Value of the protirelin test].
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[Bladder wall hematoma from anticoagulants. A rare complication].
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[Nutrition in the aged and dental prostheses].
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[The treatment of Cushing's syndrome by selective excision of pituitary adenoma. 3 cases (author's transl)].
In three patients suffering from Cushing's disease, exploration revealed an enclosed pituitary adenoma in one case and a microadenoma in two cases. Selective excision via a transphenoidal approach resulted in cure of Cushing's disease as reflected by complete regression of clinical signs and the restoration of circadian rythm of cortisol. Regular follow-up over a period of more than two years showed the persistence of normal regulation of the corticotrophic sector of the pituitary.