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Biomedical subjects

C Rey

Publications and source records attributed to C Rey.

At least 145 records · Page 8Linked to original sources
PubMed1997

[Value of detachable silicone balloon in the closure of coronary artery fistula. Apropos of 3 cases].

Surgical treatment of coronary artery fistulae is being progressively suppleated by interventional cardiology. Each method has its advantages and drawbacks. The authors report their experience with a silicone balloon inflated with contrast (ITC) and released into the fistula. Between May and September 1996, percutaneous embolisation of coronary artery fistulae was attempted by this technique in 3 children aged 8 months, 6 and 7 years. One had a right coronary artery to right ventricle fistula, the second had a right coronary artery to right atrium fistula and the third a left coronary artery to right ventricle fistula. The infant with a left-to-right shunt required digitalo-diuretic therapy and the 7 year old child had undergone surgical ligature with immediate repermeabilisation of the fistula 2 years previously. Catheterization was performed under general anaesthesia in 1 case and local anaesthesia in 2 cases. In all patients, complete occlusion was obtained when the balloon was inflated. However, in the infant, electrocardiogram signs of ischaemia were observed due to the distal origin of coronary vessels. The outcomes were uncomplicated. One child developed partial ischaemia of the lower limb which regressed with regressed with fibrinolysis and heparin therapy. The authors conclude that this is a reliable and safe technique for occluding large coronary artery fistulae. The results on the myocardium of occlusion can be assessed before final release of the balloon. For this reason, it may be proposed as the method of first intention before cardiac surgery.

Catheterization↗
PubMed1997

[Secondary subaortic obstruction after correction of double outlet right ventricle. Echocardiographic aspects and surgical findings].

The authors report echocardiographic appearances of subaortic obstruction secondary to correction of double outlet right ventricle in 8 children reoperated between January 1994 and June 1996. The initial repair of the double outlet right ventricule was performed before 3 months of age in 6 cases. Forms with subaortic ventricular septal defects (4 cases) and those with ventricular septal defects not connected to the great arteries (2 cases) were treated by tunneling between the left ventricule and the aorta, and forms with subpulmonary ventricular septal defects (2 cases) by tunneling between the left ventricle and pulmonary artery and detransposition. Reoperation for subaortic obstruction was performed after 18 to 33 months. The instantaneous maximal gradient measured by Doppler echocardiography was high, ranging from 60 to 145 mmHg. The causes of the secondary subaortic obstruction were stenosis of the tunneling patch (n = 2), subaortic fibrous ring (n = 3), muscular septal hypertrophy (n = 1), antero-lateral muscular hypertrophy (n = 1), relics of tricuspid tissue inserted on the infundibular septum (n = 1). Subaortic obstruction was diagnosed in the echocardiographic subcostal views in all cases; the nature of the obstruction was determined in 6 of the 8 cases. The mechanism of obstruction by stenosis of the tunneling patch was only detected in 1 of the 2 cases. This study show, 2D echocardiography to be the investigation of choice for follow-up of operated double outlet right ventricle for the diagnosis of secondary subaortic obstruction.

Adult↗
PubMed1997

[Prognosis and outcome of idiopathic dilatation of the right atrium in children. A cooperative study of 15 cases].

Idiopathic dilatation is a rare abnormality corresponding to isolated aneurysmal dilatation of the right atrium, the outcome of which is not well known. Therefore a multicentric retrospective study was set up by the paediatric working group of the French Society of Cardiology recensing 7 boys and 8 girls who were diagnosed with this condition between 1971 and 1993. Ten of the children were asymptomatic and the diagnosis was suggested by the chest X-ray: one neonate had cardiac failure secondary to atrial tachycardia. The diagnosis has been facilitated by echocardiography since 1980. In this series, since 1993, four diagnoses were made antenatally. The outcome was variable : eight children are alive and well with follow-up periods ranging from 2 to 15 years (average 6 years) : four children have had cardiac arrhythmias : benign atrial extrasystoles (1 case), junctional reentrant tachycardia (1 case). The other two had more severe arrhythmias with flutter in a 7 year-old and one neonatal atrial tachycardia. The outcome was favourable with medical treatment. Three children underwent surgical atrial resection : the outcome has been good in these 3 cases with follow-up periods of 4, 13 and 18 years. This series shows that idiopathic dilatation of the right atrium is usually a well tolerated abnormality but unexpected complications may arise which can be severe such as arrhythmias, or which may be potentially threatening such as interatrial thrombosis. Management consists of either follow-up to diagnose complications which require appropriate treatment of systematic surgical correction as some authors suggest.

Adolescent↗
PubMed1997

[Value of the tilt-table test in the management of unexplained syncope in children and adolescents].

The value of the tilt test in assessing unexplained syncope in children and adolescents was investigated in 79 patients (41 girls and 38 boys, 12.3 +/- 2.9 years). The test was performed with a tilt of 60 degrees for 45 minutes. A pharmacological provocation with isoprenaline was carried out in negative passive test. The tilt test was considered to be positive in cases of symptomatic falls of the systolic blood pressure with or without bradycardia. Asystole was defined as a ventricular pause > or = 5 seconds. During the investigation, 52 patients (66%) reproduced symptoms related to vasovagal syncope in 45 patients (57%) or panic attack in 7 others (9%). Of the 45 presenting vasovagal syncope, 7 had a cardio-inhibitory reaction with asystole of 11.2 +/- 3.3 seconds. The other responses were vasodepressive in 17 patients and mixed in 21 patients. A comparative study did not reveal any significant difference between patients with a positive or negative test including those with panic attacks. Seventy-five patients were followed up for an average of 32 +/- 22.3 months. Preventive therapy was prescribed in 34 patients because of the frequency or severity of their symptoms. At the end, 10 patients (13%) had at least one recurrence of syncope, 3 in the group with panic attacks, 5 in non-treated patients (irrespective of the result of the tilt test) and only 1 in the group of 23 patients treated with beta-blockers. The authors conclude that with a diagnostic return of 66% in this series, the tilt test seems to be the non-invasive investigation of choice in unexplained syncope in children and adolescents. In addition, true vasovagal syncope can be differentiated from psychogenic.

Adolescent↗
PubMed1997

[Amyloidosis AL of the breast in an ileal carcinoid tumor].

An ileal tumor was detected in a patient with monoclonal plasmocytosis of the bone marrow (IgA Kappa). The pathological examination showed a carcinoid tumor with amyloid stroma. Immunotyping of the amyloidosis showed that it was stained with the antibody directed against light chain kappa, though the amyloidosis was located within a carcinoid tumor.

Amyloidosis↗
PubMed1996

Variation in the inflammatory properties of basic calcium phosphate crystals according to crystal type.

OBJECTIVE: To determine the inflammatory potential of basic calcium phosphate (BCP) crystals, which have been identified in human joints. METHODS: Hydroxyapatite, carbonate apatite, whitlockite, and octacalcium phosphate crystals were injected in rat air pouches. Volume and cellularity of the exudate were measured. Physicochemical properties of the injected BCP crystals were determined, and correlations with the magnitude of induced inflammatory responses were sought. RESULTS: Significant differences were observed among the volumes and white blood cell (WBC) counts of the pouch exudates, based on the various crystal types used to induce inflammation. A strong correlation was demonstrated between the specific surface (SS) area of the injected crystals and the area under the curve for induced WBC count versus time (R2 = 0.88, P = 0.05). This correlation was observed for SS area values below 50 m2/gm, but when SS area increased further, this parameter plateaued. Another parameter of inflammatory response was obtained by dividing the area under the curve figuring WBC counts versus time by the corresponding SS area for each crystal type. This parameter increased linearly with the Ca:P ratio (R2 = 0.97, P = 0.0003). CONCLUSION: The inflammatory potential of BCP crystals appeared to vary according to crystal features. SS area and the Ca:P ratio (which correlates with crystal solubility) influenced inflammatory properties. These results could explain the variable clinical consequences of BCP deposits, and must be taken into account in the choice of apatite ceramics for use as biomaterials.

Animals↗
PubMed1996

Acquisition of syncytium-inducing HIV-1 strains during therapy with zidovudine alone or combined with alpha interferon or didanosine.

The effect of antiretroviral treatment on HIV-1 phenotype was studied in a group of 83 nucleoside-naive patients. These initially nonsyncytium-inducing HIV-1 positive patients were followed prospectively for their HIV-1 phenotype. Syncytium-inducing variants were detected by cocultivation of peripheral blood mononuclear cells with the MT-2 T-cell line. Overall, 16 of 83 (19%) patients underwent a shift to syncytium-inducing phenotype: 11 of 67 during zidovudine treatment, 3 of 10 during zidovudine plus alpha interferon treatment, and 2 of 6 under initial zidovudine plus didanosine therapy. The results of this study demonstrate that neither zidovudine therapy alone nor combined with interferon or didanosine prevents the acquisition of syncytium-inducing strains.

Adult↗
PubMed1996

X-ray diffraction, electron microscopy, and Fourier transform infrared spectroscopy of apatite crystals isolated from chicken and bovine calcified cartilage.

Apatite crystals of the calcified zone of the subarticular cartilaginous growth plates of the long bones of young growing chickens and calves were isolated by low temperature reaction with hydrazine and plasma ashing and examined by electron microscopy, electron diffraction and microprobe analysis, and computer-generated deconvolution of the spectra obtained by Fourier transform infrared spectroscopy. The crystal habit was that of wide, very thin, relatively long rectangular plates, which tended to form small clusters of crystals, possibly because reaction with hydrazine alone did not remove all of the organic matrix constituents. Further reaction with low power plasma ashing released more of the isolated crystals although to a lesser extent than was possible with bone. Stereograms of the small clusters showed that many of the crystals in the small isolated aggregates of crystals were bent and/or curved. Together with the resultant overlap of individual adjacent crystals, they also produced images of sharp, very dense lines, reminiscent of the electron-dense needle or rod-like appearances frequently observed by transmission electron microscopy of thin sections of calcified cartilage and thought to represent the habit of the apatite crystals. No true rod or needle-like crystals were observed in the isolated crystals. Although the overall general apatitic structure of the apatite crystals was similar to that of the apatitic crystals of bone, the individual crystals were significantly larger than those of bone from the same specimen, and there were small but significant differences in the concentrations of acid phosphate and carbonate groups and in their short range order.

Animals↗
PubMed1996

Occlusion of large atrial septal defects with a centering buttoned device: early clinical experience.

A feasibility clinical study was conducted for the transcatheter occlusion of large ostium secundum atrial septal defects with the centering buttoned device. The centering buttoned device is a modification of the regular buttoned device in which a centering counter-occluder is sutured at the central 40% portion of the occluder. During centering it is stretched, forming a parachute-shaped structure and pulling the occluder over the center of the defect. During buttoning, the counter-occluder forms a double figure eight, opposing the right atrial side of the atrial septum. Occlusion was performed in 12 patients aged 6 to 56 years. All had been rejected for transcatheter occlusion by the regular buttoned device, because of either their defect size or the lack of adequate septal rim. The defect size varied between 23 and 31 mm, and the device size varied between 45 and 60 mm. Nine had immediate effective occlusions of their defects and three residual shunts. One patient with unbuttoning had hemolysis at 2 weeks and underwent surgery. Early results of the transcatheter occlusion of large atrial septal defects are promising, and larger clinical trials are justified.

Adolescent↗
PubMed1996

Rate of development of mutation at codon 215 of HIV-1 reverse transcriptase and its predictive factors at the time of initiation of zidovudine therapy.

The objective of the present study was to determine the rate of development of mutation at codon 215 of HIV-1 reverse transcriptase and to identify baseline characteristics associated with this mutation following initiation of zidovudine therapy. To achieve such a purpose, 80 HIV-1-infected patients starting zidovudine therapy have been submitted to clinical, immunological and virological monitoring at entry and every 12 weeks. The critical end point of the study was time to development of mutation at codon 215. The association of key baseline characteristics (CD4+ counts, clinical stage, HIV-1 p24 antigen, CD8+ counts, serum beta 2-microglobulin and virus phenotype) with the mutation at codon 215 was also investigated. A total of 38 subjects (48%) developed mutation at codon 215 during follow-up. The estimated Kaplan-Meier probability of remaining with wild genotype at 24, 48 and 96 weeks (96% CI) was 0.82 (0.73-0.90), 0.70 (0.60-0.80) and 0.53 (0.41-0.66) respectively. Univariate analysis showed that time to the development of mutation at codon 215 was positively associated with baseline p24 positivity, C clinical stage, low CD4+ count and high beta 2-microglobulin level. Only p24 antigenaemia and CD4+ count remained significantly independent predictive factors for the development of mutation at codon 215 in the Cox proportional hazard stepwise regression analysis [risk ratio (95% CI): 3.67 (1.75-7.70), P = 0.0007; 2.89 (1.17-6.72), P = 0.0073 respectively]. Thus, a continuous emergence of mutation at codon 215 was observed and HIV-1 p24 antigenaemia should be considered an independent predictor for faster development of zidovudine resistance.

Adolescent↗
PubMed1996

HIV-1 viraemia changes in patients with and without syncytium-inducing phenotype treated with nucleoside analogues: a case-control study.

The objective of the present study was to investigate the effect of the nucleoside analogue treatment on serum viraemia, CD4+ cell count and disease progression in patients with and without syncytium-inducing (SI) HIV-1 variants. To achieve this in a case-control study, 11 nucleoside-naive patients harbouring SI variants who started treatment with zidovudine or zidovudine plus didanosine were matched with 11 control patients who never formed SI variants during a follow-up of 48 weeks. The matching criteria were age, CD4+ cell count and CDC clinical category at the start of the study and exposure to the same antiretroviral treatment. During the follow-up there were no significant differences in the changes of serum HIV-1 RNA viral load and CD4+ cell counts between the two groups. In contrast, AIDS or new AIDS-defining events were observed in five SI cases but in none of the non-SI controls (P = 0.002). The emergence of a zidovudine-resistant mutation at codon 215 was observed in all the patients harbouring SI strains and in six of the subjects with non-SI variants (P = 0.03). The results of the present study show that in patients carrying SI virus, measurements of CD4+ count or RNA viral burden are neither related to the virulence of the virus strains nor able to predict the clinical course of the disease, at least under anti-retroviral drug conditions. Thus, determination of SI phenotype should be considered in the evaluation and monitoring of HIV-1 therapies.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Chronic renal failure and human growth hormone treatment do not modify endothelium-dependent reactions in the rat aorta in vitro.

1. Growth hormone (GH) increases glomerular filtration rate and renal plasma flow and decreases renal vascular resistance. Sustained GH-induced hyperfiltration might be undesirable in children with chronic renal failure (CRF) who are receiving recombinant human GH (rhGH) therapy. 2. In order to determine the effect of CRF on vascular reactivity and the modifications induced by rhGH administration, two endothelium-dependent effects, acetylcholine relaxation and decrease of contractile response to noradrenaline, were studied in aorta segments of various groups of male Sprague-Dawley rats: CRF rats (CRF, n = 8) with serum urea nitrogen (SUN) 68 +/- 16 mg dl-1 (mean +/- SEM), CRF rats treated with intraperitoneal rhGH at 10 IU kg-1 day-1 for 13 days (CRFGH, n = 6, SUN = 88 +/- 15 mg dl-1), sham operated rats (SHAM, n = 8, SUN: 21 +/- 1 mg dl-1) and control rats (CONTROL, n = 8, SUN 20 +/- 1 mg dl-1), housed in identical conditions but without undergoing surgical intervention or manipulation. CRF was induced by 5/6 two stage nephrectomy. 3. Rats were sacrificed and a segment of thoracic aorta was immediately removed, cut into spirals, and suspended in organ baths according to standard procedures. First, dose-response curves to noradrenaline and acetylcholine relaxation, in strips previously exposed to noradrenaline, were determined. Then, the endothelium was removed and both dose-response curves were repeated. Acetylcholine induced a greater relaxation, P < 0.05, in the aorta of CONTROL rats (82.6 +/- 6.1%) as compared with SHAM (60.3 +/- 4.7%), CRF (60.0 +/- 6.8%) and CRFGH (54.8 +/- 8.2%) rats. 4. Endothelium removal only caused a greater contractile response to noradrenaline (10(-9) and 3 x 10(-9)M) in the CONTROL group, P < 0.05. 5. No differences to acetylcholine and noradrenaline responses were found among the SHAM, CRF and CRFGH groups. 6. These results suggest that the endothelium-dependent vascular reactivity was modified by the experimental protocol to induce chronic renal failure but no further changes resulted from uraemia and rhGH treatment.

Acetylcholine↗
PubMed1996

Effects of valproate-induced alteration of the GABAergic system on pulsatile luteinizing hormone secretion in ovariectomized women.

It is well established that valproate increases hypothalamic concentrations of gamma-aminobutyric acid (GABA). Although little research has been done on the role of GABA in the control of pulsatile luteinizing hormone (LH) secretion in humans, our group recently found that administration of valproate had no significant effect on pulsatile LH secretion in late follicular and mid-late luteal phase normal women. However, the results of several studies of rats suggest that GABAergic regulation of LH secretion may depend on steroid levels. The objective of this work was to determine whether regular administration of sodium valproate inhibits pulsatile LH secretion in ovariectomized women. Twelve women who had undergone ovariectomy for causes other than malignant tumors were each studied in two 8 h sessions, in each of which blood samples were taken every 5 min. The first session was the control; for the second. 400 mg of sodium valproate was administered every 8 h during the seven preceding days and at 08.00 h and 14.00 h on the day of the study session. Serum valproate was determined by repolarization fluorescence spectrophotometry, and LH, estradiol and progesterone by radioimmunoassay. The serum LH series were subjected to a deconvolution procedure to reconstruct the pattern of pituitary LH secretion. Luteinizing hormone pulses were identified by the authors' non-parametric method. Control and post-valproate results were compared with regard to number of pulses, pulse duration, the quantity of LH secreted in each pulse, interpulse interval and mean serum LH level. There was no statistically significant difference between control and post-valproate results for any of the variables considered. It is concluded that sustained serum valproate levels do not alter pulsatile secretion of LH in ovariectomized women. This implies that, in humans, GABA is probably not a decisive factor in the regulation of the GnRH pulse generator.

Adult↗