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Biomedical subjects

G Coutris

Publications and source records attributed to G Coutris.

At least 19 recordsLinked to original sources
PubMed1999

Effects of chronic treatment by amiodarone on transmural heterogeneity of canine ventricular repolarization in vivo: interactions with acute sotalol.

OBJECTIVE: The present study was designed to examine the effects of chronic amiodarone on the different ventricular cell subtypes in situ and to evaluate its interactions with sotalol. METHODS: Three groups of dogs were studied. Group I (n = 8) received no treatment. Group II (n = 7) and group III (n = 8) received, respectively, 100 and 200 mg amiodarone orally twice a day for 6 weeks to 8 months. In vivo studies were performed under halothane anesthesia 14 h after the last administration of amiodarone. Three leads ECG, femoral blood pressure and left ventricular intramural monophasic action potentials (MAP) were continuously recorded. Bradycardia was obtained by clamping the sinus node and beta-blockade and the heart was driven by atrial pacing. Three weeks before the in vivo experiments, the cellular electrophysiologic properties of right ventricular tissues obtained by cardiac biopsy in six treated and six control dogs were studied with standard microelectrodes. RESULTS: Amiodarone produced a dose-dependent decrease in plasma levels of triiodothyronine (T3; 5.9 +/- 0.4 pM in control dogs, 3.1 +/- 0.2 pM in group III, P < 0.001) without affecting thyroxine (T4). Under anesthesia, the QT interval was 14% larger in group III compared to group I at a paced cycle length (PCL) of 1500 ms (P < 0.05). This is consistent with the 10% increase in endocardial MAP duration in group III at the same PCL (P < 0.05). There was no significant increase in transmural dispersion of MAP duration. In group I, sotalol induced a significant reverse use-dependent increase in MAP duration. This effect was reduced in group II and completely suppressed in group III. Amiodarone prevented the sotalol-induced increase in transmural dispersion of ventricular repolarization which was 69 +/- 12 ms in untreated dogs, 41 +/- 8 ms in group II (P < 0.05) and 34 +/- 8 ms (P < 0.05) in group III at PCL = 1500 ms. Amiodarone also prevented the sotalol-induced ventricular tachyarrhythmias. In vitro, the action potential duration was longer in amiodarone-treated dogs that in control ones (208 +/- 5 ms versus 188 +/- 9 ms at PCL = 1000 ms, P < 0.05). The sotalol-induced prolongation of repolarization was reduced in amiodarone-treated dogs. CONCLUSION: Chronic treatment of dogs with amiodarone induced a moderate prolongation of the QT interval and MAP duration without affecting transmural dispersion of repolarization and inhibited the effects of acute sotalol, including the prolongation of repolarization, the increase in transmural dispersion of repolarization and the induction of arrhythmias.

Action Potentials↗
PubMed1994

Aluminium-related osteodystrophy and desferrioxamine treatment: role of phosphorus.

We investigated (1) the prevalence of aluminium overload among 96 patients with symptomatic bone disease haemodialysed from 1987 to 1989 in the Sao Paulo area, Brazil; (2) the effect of 6 months desferrioxamine (DFO) treatment (1-2g/week). All patients underwent a first bone biopsy. Aluminium overload (extent of stainable bone aluminium more than 20% trabecular surface) was observed in 74 of 96 patients. Forty overloaded patients were divided into patients with high bone formation rate (BFR) (group 1; n = 17) and patients with low BFR (group 2; n = 23), and had a second biopsy after DFO therapy. In both groups aluminium surface was reduced after treatment (P < 0.001), osteoblast surface (P < 0.02-P < 0.01) and plasma parathyroid hormone (iPTH) (P < 0.01) increased. In group 1 BFR remained high. In group 2 BFR remained low in 16 patients (2a) and increased in seven (P < 0.02) (2b). In group 2a plasma phosphorus was below that in group 2b patients, before (P < 0.03) and after (P < 0.01) DFO. The histological features of group 2a patients resembled hypophosphataemic osteomalacia, those of group 2b patients aluminium osteodystrophy. These data show a high prevalence of aluminium overload in Brazilian patients. Low-dose DFO therapy was safe, decreased bone pain, prevented fractures, and reduced stainable bone aluminium. Bone lesions only partially improved, suggesting that low phosphorus intake and/or plasma calcitriol concentrations may have prevented improvement of bone formation and mineralization.

Adolescent↗
PubMed1993

[Biliary scintigraphy. Application to the study of chronic cholestasis].

In a sample population of 49 subjects (7 normal, 42 with various liver diseases), the parameters of the activity/time curve of trimethylbromo-iminodicetic acid (TBIDA) biliary scintigraphy were compared with the clearances of bromosulfophthalein (BSP) and indocyanine green (ICG). Correlation between T1/2 and P2 BSP slope was r = 0.50 (n = 33; P < 0.01). Correlation between Tmax TBIDA and fractional ICG clearance (P ICG) was r = 0.65 (n = 44; P < 0.001). In 23 cases of chronic cholestasis correlations remained significant (T1/2-P2 BSP: r = 0.53; n = 17; P = 0.02; Tmax-P ICG: r = 0.59; n = 17; P < 0.01). A prospective study of 11 cases of chronic intrahepatic cholestasis (primary biliary cirrhosis 8, primary sclerosing cirrhosis 3) showed that these two types of tests varied concordantly. Biliary scintigraphy, therefore, seems to be an accurate method to explore hepatocellular mass (degree of hepatic insufficiency) and cholestasis. The validation of biliary TBIDA scintigraphy as hepatobiliary functional exploration method and the possibility to study intrahepatic "regions of interest" defined a priori would make it possible to obtain a functional estimate of hepatic segments or lobes, for example before wide liver excision.

Aged↗
PubMed1993

Utility of thallium-201 and iodine-123 metaiodobenzylguanidine in the scintigraphic detection of neuroendocrine neoplasia.

Metaiodobenzylguanidine (MIBG) is a specific marker for neuroendocrine tumours, such as phaeochromocytoma, neuroblastoma, medullary thyroid cancer (MTC) and paraganglioma, but it suffers in some cases (especially in MTC) from a lack of sensitivity. Thallium is a well-known marker of cellularity with a great sensitivity and a lack of specificity. In order to determine whether the association of these two markers is able to improve the detection of neuroendocrine lesions, 137 scintigraphic examinations using MIBG and thallium were performed in 101 patients referred for suspicion or follow-up of neuroendocrine tumours. Thallium chloride was first injected (1 MBq/kg), images being acquired about 20 min after injection; 123I-MIBG (4 MBq/kg) was then injected and images acquired 5 and 24 h later. In patients with phaeochromocytoma or neuroblastoma, thallium scintigraphy appeared of little help since no tumoural site was discovered by thallium accumulation alone. In contrast, thallium examination seemed of interest in the detection of paraganglioma and MTC, the association of the two radiopharmaceuticals increasing the number of detected sites.

3-Iodobenzylguanidine↗
PubMed1992

Correction of severe secondary hyperparathyroidism in two dialysis patients: surgical removal versus percutaneous ethanol injection.

Two chronic hemodialysis patients had recurrent, severe secondary hyperparathyroidism. The first had no sonographically visible parathyroid gland in the neck. Computed tomography (CT) scan indicated the existence of a parathyroid mass in the upper mediastinum, which was removed surgically. The second patient had two intracervical, hyperplastic parathyroid glands visible on ultrasound examination. He volunteered for nonsurgical removal via sonographically guided percutaneous injection of ethanol. In both patients, serum total calcium concentration decreased dramatically to values near 1.5 mmol/L 24 hours after treatment. In patient 1, serum immunoreactive parathyroid hormone (iPTH) (1-84) decreased from 1,582 pg/mL before surgery to 34 pg/mL after 24 hours (normal range, 10 to 65 pg/mL). In contrast, serum iPTH (1-84) decreased only progressively in patient 2, from 1,680 pg/mL before ethanol injection to 865 pg/mL after 24 hours and to 378 pg/mL after 72 hours to reach 30 pg/mL after 14 days. Thus, patient 2 had a striking decrease of plasma calcium immediately after parathyroid gland destruction, even though circulating iPTH was still very high. The reason for such a discrepancy remains unexplained at present, and further study will be necessary to solve this issue.

Adult↗
PubMed1991

[Thyroid cancer revealed by a suppressive hot nodule].

We report the case of a 62-year old woman in euthyroidism who presented with a thyroid cancer located within a hot nodule. The nodule was partially extinctive, and the triiodothyronine test showed incomplete suppression. Fine needle cytology showed no malignant cells. Systematic lobectomy was performed, and the diagnosis of cancer was made at pathology. This rare situation does not mean that all non-toxic hot nodules must be removed, but if surgery is decided an extemporaneous histological examination is mandatory. Besides, such cases provide an additional argument in favour of surgery or treatment of toxic adenomas.

Female↗
PubMed1987

Radioiodinated meta-iodobenzylguanidine uptake in medullary thyroid cancer. A French cooperative study.

Fifty meta-iodobenzylguanidine (MIBG) scintiscans were performed in three groups of medullary thyroid cancer (MTC) patients. Group 1 (n = 11) included treated patients with normal calcitonin levels; Group 2 (n = 24) included patients with elevated calcitonin levels due to sporadic and isolated MTC; Group 3 (n = 15) included patients with elevated calcitonin levels due to familial MTC or multiple endocrine neoplasia Type IIA syndrome (MEN). In Group 1 three pheochromocytoma were depicted by MIBG scintiscan. In Group 2 MTC was seen in a small number of patients (3 of 24). In Group 3, besides adrenal hyperplasia and pheochromocytoma four patients, MIBG scintigraphy showed where MTC had localized and spread in almost half of patients (7 of 15). MIBG uptake occurred in patients with relatively high calcitonin level (greater than 0.6 nmol/l). These data indicate that in patients with familial MTC or MEN syndrome, MIBG scintiscan can be useful not only in detecting associated pheochromocytoma, but also in showing MTC.

3-Iodobenzylguanidine↗
PubMed1986

Uptake of 131I-MIBG by medullary carcinoma of thyroid in familial cases.

Medullary carcinoma of the thyroid (MCT) and pheochromocytoma are APUD tumors. MIBG (Meta Iodo Benzyl Guanidine) uptake by pheochromocytomas is now well known but very few cases of MIBG uptake in sporadic MCT have been described. We report here the two first cases of inherited MCT with MIBG uptake.

3-Iodobenzylguanidine↗
PubMed1985

[Risk of vertebral fracture after menopause: identification of subjects at high risk by dual photon absoprtionometry].

Dual photon absorptionometry of bone is used to detect in an exposed population those subjects who are high risk of fracture and also to follow up the evolution of these patients. 37 women who have suffered fractures have been compared to 41 women without fractures of similar age distribution. A highly significant correlation between body height and Bone Mineral Content (BMC) of the lumbar spine is found in the control group thus allowing the calculation of the expected BMC value for each patient. A crushing index is defined as the ratio of the observed BMC value to the expected one. Using this index, instead of the two more usual modes of BMC expression, leads to an improvement of the predictive estimation of fracture risk. The predictive value of such indices should still be improved. With this aim, further determinations of indices are desirable. The following requirements should be borne in mind: The physical data should be easily obtainable e.g. body height and weight and the meaning of the index based on these easily verifiable factors they should be easily understood.

Aged↗
PubMed1984

[Experimental schistosomiasis III. Observations on the infestation of Biomphalaria glabrata by a miracidium of Schistosoma mansoni].

380 B. glabrata infected with 1 miracidium of S. mansoni produced 87 positive snails (22,9%), 38 of which sending out male cercariae and 49 female cercariae. The snails belonged to 3 experimental series kept at 27 degrees and 24 degrees C for 15 weeks under continuous lighting. There was no difference between the proportions of both sexes. The survival of the positive snails was favoured by the male sex. The shedding of female cercariae was greater than shedding of male. During those 15 weeks, the cercarial shedding of both sexes showed large and recurring changes. A certain correlation seems to exist between the sex of cercariae, the abundance and the frequency of cercarial shedding, and the longevity of the parasitized snails. All those factors could take a part in the epidemiology of the schistosomiasis.

Animals↗
PubMed1981

[Chromosome abnormalities associated with Phl and acturial survivorship curve in chronic myeloid leukemia. Probabilistic interpretation of blastic transformation of CML].

Sixty-six patients with chronic myelogenous leukemia, all with Philadelphia chromosome, have been studied for chromosomic abnormalities associated (CAA) to Ph', as well as for actuarial curve of survivorship. Patients dying from another disease were excluded from this study. Frequency of cells with CAA was measured and appeared strongly higher after blastic transformation than during myelocytic state; probability to be a blastic transformation is closely correlated with this frequency. On the other hand, actuarial curve of survivorship is very well represented by an exponential curve. This suggests a constant rate of death during disease evolution, for these patients without intercurrent disease. As a mean survivance after blastic transformation is very shorter than myelocytic duration, a constant rate of blastic transformation could be advanced: it explains possible occurrence of transformation as soon as preclinic state of a chronic myelogenous leukemia. Even if CAA frequency increases after blastic transformation, CAA can occur a long time before it and do not explain it: submicroscopic origin should be searched for the constant rate of blastic transformation would express the risk of a genic transformation at a constant rate during myelocytic state.

Chromosome Aberrations↗
PubMed1979

A technique for multiple, high-rate blood samplings via an external cannula in rats.

A method for obtaining multiple, high-rate blood sample collections from rats without the use of anesthesia and anticoagulant is described. The surgical procedure consists of a bypass of the carotid via a cannula; this cannula forms a loop above the rat's head and is available for blood sampling. The method permits the investigation of high-frequency oscillations in blood components of rat.

Animals↗
PubMed1975

[Tests of stimulation of calcitonin secretion. Value in medullary cancer of the thyroid].

The detection of high circulating levels of calcitonin is a most valuable procedure to diagnose advanced cases of medullary carcinoma of the thyroid. However, the diagnosis of a primitive tumor in the early stages of development (as in cases of the familial form of the disease) or of a metastasis following ablation of the tumor is more difficult. In the latter cases, the levels of circulating calcitonin may be within normal limits, and for diagnosis one must then resort to tests to stimulate the secretion of calcitonin. We are reporting from our personal experiences the advantages, disadvantages and inconveniences of the three most well-known tests. All patients responded positively to administration of calcium or pentagastrin. The alcohol test, however, produced inconsistent results.

Adult↗
PubMed1975

[Multidimensional analysis in clinical investigation. Application to the pathogenic classification of idiopathic hypercalciuria].

Multidimensional analytical techniques enable any number of variables to be studied simultaneously. These techniques have been described and a few examples of their application to biomedical research given. A classification of so called "idiopathic hypercalciuria" was made using this approach which demonstrated the existence of three possible mechanisms of pathogenesis.

Analysis of Variance↗
PubMed1975

[Analysis of disorders of the principal pathways of calcium metabolism in Paget's disease. Effects of calcitonin administration. 26 cases].

Analysis of the principal routes of calcium metabolism by means of calcium-45 in 26 patients suffering from Paget's diseases sometimes showed, in agreement with data from the literature, a considerable increase in the common stocks of calcium in 25 cases, and an elevation in the anabolism (Vo+) in bone and in the catabolism (Vo-) in bone in all cases. The calcium balance was sometimes equal, but often clearly positive (10 cases) or negative (10 cases) and the level intestinal absorption of calcium was usually within the normal limits. An elevation in the endogenous fecal calcium (Vf) noted in half of the cases, although no value was below normal, seemed to represent an metabolic anomaly of abnormally high frequency in patients with Paget's disease, even though this fact has never been emphasized before. Statistically significant correlations were shown between the values of different kinetic and metabolic parameters in the group of patients studied. A second kinetic study carried out after several weeks of treatment with porcine calcitonin showed a statistically significant diminution in the values of Vo +, Vo -, endogenous fecal calcium, calciuria, hydroxyprolinuria, and in alkaline phosphatasaemia, as well as significant variations in the calcium balance in a positive direction. The common calcium stocks did not show a significant diminution, contrary to the findings of other authors. The level of intestinal absorption of calcium increased more often than it decreased, but the magnitude of the variations was slightly less than the level of statistical significance.

Aged↗