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Biomedical subjects

C Rey

Publications and source records attributed to C Rey.

At least 253 records · Page 14Linked to original sources
PubMed1991

Growth hormone metabolism in uremia.

The influence of chronic renal failure (CRF) on growth hormone (GH) and insulin-like growth factor I (IGF-I) metabolisms is not well understood. Clinical studies on GH secretion in CRF have yielded conflicting results. In vitro, pituitary GH secretion has been shown to be unimpaired in moderate uremia. CRF reduces binding of GH to liver as a result of decreased number of GH receptors. CRF induces elevation of serum GH concentrations and does not modify the circulating values of IGF-I. However, the somatomedin bioactivity of uremic serum is depressed, and unsaturated low-molecular-weight IGF-I-binding proteins have been suggested to act as inhibitory factors of IGF-I action. Circulating GH and IGF-I do not necessarily reflect the state of GH and IGF-I in tissues, and further investigations on the effect of CRF on GH and IGF-I metabolisms at the growth plate level are clearly required.

Child↗
PubMed1991

[Aortic valve insufficiency: an unrecognized complication of the surgical repair of ostium primum atrial septal defect].

Between 1974 and 1989, eight children undergoing surgical repair of a partial atrioventricular canal comprising an ostium primum atrial septal defect, mitral regurgitation due to a cleft mitral valve (6 cases) and a small ventricular septal defect (1 case) developed aortic regurgitation. This complication was diagnosed on the finding of a diastolic murmur 1 day to 9 years after the repair of the atrial septal defect. The degree of regurgitation was Grade I in 4 cases but in the other patients it was severe from the outset requiring emergency surgery the next day (1 case), or moderate at the beginning but rapidly progressive (1 case) or slowly progressive (2 cases) leading to aortic valvuloplasty in these 3 patients. The cause of the regurgitation was iatrogenic: perforation of the non coronary cusp secondary to repair of the ostium primum atrial septal defect. None of the patients required aortic valve replacement. After surgical valvuloplasty, all children had Grade 1 aortic regurgitation. Color coded Doppler echocardiography confirmed the diagnosis and helped assess the clinical course of this lesion during follow-up.

Adolescent↗
PubMed1991

[Holter monitoring, exercise test and atropine test in isolated congenital atrioventricular block in children].

Twenty-four patients with isolated congenital heart block were investigated by 24-hour Holter monitoring at an average age of 9.3 +/- 5.5 years. Six patients were symptomatic and 18 were asymptomatic. Eight asymptomatic patients underwent exercise stress tests and an atropine test was performed in 10 asymptomatic patients to evaluate the capacity to accelerate the heart rate. The symptomatic patients were older than the asymptomatic patients. None of the parameters which analyse ventricular rate were significantly different in the two groups of patients. Significant ventricular arrhythmias (Lown Grade 2 or over) were recorded in 1 symptomatic and 3 asymptomatic patients. The incidence of these ventricular arrhythmias increased with age and degree of bradycardia. The percentage increase in ventricular rate after atropine correlated with what was observed on effort (r = 0.95, p = 0.01) but there was no relationship between the ventricular rates during these two tests and those recorded on Holter monitoring. The results of this series of children with isolated congenital heart block show the Holter parameters cannot distinguish symptomatic from asymptomatic patients. The exercise stress and atropine tests gave very similar results but their prognostic value has not yet been established.

Adolescent↗
PubMed1990

[Pediatric interventional cardiology].

Interventional catheterization is performed in children as a palliative or curative treatment during venous, arterial or cardiac exploratory catheterization. It is used to create an interatrial shunt; to suppress venous or arterial stenosis by balloon catheter angioplasty; to dilate stenotic cardiac valves, also with balloons; to occlude arteriovenous shunts by different methods (metallic spirals, detachable balloons, Spongel fragments, biological glues), or to close a ductus arteriosus by means of an umbrella introduced through a femoral vein.

Angioplasty, Balloon, Coronary↗
PubMed1990

[An evaluation of the efficacy of different commercial kits in the serological diagnosis of the early phase of human immunodeficiency virus infection].

The aim of the present study was to identify the most useful serum markers for the early identification of the infection by the human immunodeficiency virus (HIV). To this end, sequential serum samples of 19 individuals who later had seroconversion to anti-HIV were evaluated. The p24 antigen (Ag-HIV) was the earliest marker of the infection, although it could only be detected in five of the 19 individuals: in two as an isolated marker and in the remaining four associated to anti-HIV (first generation Western blot: WB-1, and recombinant enzyme immunoanalysis: EIA-2G). In 12 of the 19 individuals, WB-1G (Pasteur) was the technique which permitted the earliest detection of anti-HIV: in five cases with bands which made the unequivocal diagnosis of the infection, and in seven with indeterminate results (anti-HIV against core or envelope antigens). The second earliest test was the detection of anti-HIV against envelope antigens with a competitive EIA-2G (Abbott). WB-1G (Sorin) detected anti-HIV in a late phase, as it was the case for EIA-1G or EIA-2G for anti-HIV against antigens encoded by the GAG gene. These results indicate that there may be remarkable differences in sensitivity among the different commercial kits. The use of EIA for Ag-HIV together with WB-1G shortens the gap period of HIV infection, even if seroconversion is identified with EIA-2G for global anti-HIV.

AIDS Serodiagnosis↗
PubMed1990

Increase of GABA-stimulated diazepam binding after lipid methylation in membrane preparations from rat brain.

Incubation of membrane preparations from rat brain with S-adenosyl-L-methionine resulted in methylation of the lipid fraction. Neither [3H]diazepam nor [3H]muscimol (a gamma-aminobutyric acid (GABA) agonist) binding was affected by this incubation. In contrast, when [3H]diazepam binding was stimulated by GABA, the methylation caused both a decrease of the minimal GABA concentration needed to produce its effect (10(-9) M instead of 10(-7) M) and an enhancement (from 36 to 66% over basal) of the GABA-stimulated [3H]diazepam binding.

Animals↗
PubMed1990

Hepatitis C virus infection in sexually promiscuous groups.

As there is insufficient data available on the spread of hepatitis C virus (HCV) infection by sexual transmission, the prevalence of anti-HCV was determined in several sexually promiscuous groups (78 female prostitutes, 55 clients of prostitutes and 146 homosexual men) who denied intravenous drug abuse. The overall HCV infection rate was much higher in the sexually promiscuous groups (8.97%, 16.36% and 5.48% respectively) than in voluntary blood donors (0.48%), suggesting that HCV infection can be transmitted by sexual intercourse. Consequently, promiscuity may be a risk factor for this infection.

Blood Donors↗
PubMed1990

Resolution-enhanced Fourier transform infrared spectroscopy study of the environment of phosphate ions in the early deposits of a solid phase of calcium-phosphate in bone and enamel, and their evolution with age. I: Investigations in the upsilon 4 PO4 domain.

In order to investigate the possible existence in biological and poorly crystalline synthetic apatites of local atomic organizations different from that of apatite, resolution-enhanced, Fourier transform infrared spectroscopy studies were carried out on chicken bone, pig enamel, and poorly crystalline synthetic apatites containing carbonate and HPO4(2-) groups. The spectra obtained were compared to those of synthetic well crystallized apatites (stoichiometric hydroxyapatite, HPO4(2-)-containing apatite, type B carbonate apatite) and nonapatitic calcium phosphates which have been suggested as precursors of the apatitic phase [octacalcium phosphate (OCP), brushite, and beta tricalcium phosphate and whitlockite]. The spectra of bone and enamel, as well as poorly crystalline, synthetic apatite in the upsilon 4 PO4 domain, exhibit, in addition to the three apatitic bands, three absorption bands that were shown to be independent of the organic matrix. Two low-wave number bands at 520-530 and 540-550 cm-1 are assigned to HPO4(2-). Reference to known calcium phosphates shows that bands in this domain also exist in HPO4(2-)-containing apatite, brushite, and OCP. However, the lack of specific absorption bands prevents a clear identification of these HPO4(2-) environments. The third absorption band (610-615 cm-1) is not related to HPO4(2-) or OH- ions. It appears to be due to a labile PO4(3-) environment which could not be identified with any phosphate environment existing in our reference samples, and thus seems specific of poorly crystalline apatites. Correlation of the variations in band intensities show that 610-615 cm-1 band is related to an absorption band at 560 cm-1 superimposed on an apatite band. All the nonapatitic phosphate environments were shown to decrease during aging of enamel, bone, and synthetic apatites. Moreover, EDTA etching show that the labile PO4(3-) environment exhibited a heterogeneous distribution in the insoluble precipitate.

Aging↗
PubMed1990

Amino acid metabolism in isolated perfused rat liver.

Conflicting evidence concerning hepatic amino acid (AA) metabolism in the isolated perfused rat liver (IPRL) led us to investigate the response of IPRL using perfusates with various AA contents. Perfusion (n = 4) with whole rat blood diluted in Krebs buffer (1:3, v/v) led to acute proteolysis on account of AA deprivation, as shown by the large release of AA (approximately 1400 mumoles in 120 min), especially branched-chain AA (BCAA) (e.g., Leu, 35.4 +/- 10.4 nmole.min-1.g-1 the first hour, 34.3 +/- 5.5 nmole.min-1.g-1 the second hour). In a first attempt to prevent proteolysis, livers (n = 4) were perfused with the previous medium supplemented with AA known for their antiproteolytic activity, at twice their physiological concentrations. Results during the first hour showed uptake of several AA (mainly alanine, glutamine, and proline), reduced release of BCAA (leucine, 12.5 +/- 6.3 nmole.min-1.g-1), and an increase in glucose and urea production. However, during the second hour, because of the use of a recirculating system, progressive AA depletion induced a reappearance of proteolysis. A two-step AA loading technique, i.e., the addition of antiproteolytic AA at the beginning of the perfusion and the addition of a balanced AA mixture at 60 min caused a further decrease in proteolysis during the 2 hr of perfusion (n = 6). Under these conditions, most AA were taken up by the liver with uptake values comparable to those observed in vivo.

Amino Acids↗
PubMed1990

Increased methylation of chloroform extractable products in brain membrane preparations after propranolol injection to the rat.

1. One and four hours after acute or chronic (8 days) intraperitoneal injection of propranolol to rat at doses up to 25 mg/kg, a beta-adrenergic receptor blockage occurred in brain homogenates, as monitored by [3H]dihydroalprenolol binding. 2. A dose-dependent increased methylation of chloroform extractable products was observed (acute treatment: 18% increase, chronic treatment: 136% increase for the dose of 25 mg/kg). 3. The implication of beta-adrenergic receptors in this effect was studied and this revealed that: (a) acute intraperitoneal injection of the less active propranolol stereoisomer (+) did not produce any effect; (b) the chronic intraperitoneal injection of salbutamol, a beta-adrenergic receptor agonist, induced a decreased methylation of chloroform extractable products (62% decrease for the dose of 2.5 mg/kg). 4. It is concluded that injection of beta-adrenergic antagonist to the rat increases basal methyltransferase activity in the brain. This induces a decreased sensitivity of the enzyme activity to noradrenaline.

Albuterol↗
PubMed1990

Renal cell carcinoma in childhood.

Renal cell carcinoma is extremely infrequent in children. We report a case of renal cell carcinoma in a 13-year-old male. Presenting manifestations were loin pain, fever, and weight loss. A palpable abdominal mass was found. Imaging studies showed a solid mass into the right kidney. Nephrectomy was performed and pathological examination demonstrated characteristic findings of renal cell carcinoma. This report emphasizes that renal cell carcinoma should be included in the differential diagnosis of renal masses in children.

Adolescent↗
PubMed1990

[Endoluminal closure of ductus arteriosus. A cooperative study].

Thirty-two patients from 3 Pediatric Cardiological Centres underwent attempted endoluminal transcatheter closure of a patent ductus arteriosus. The patients' age ranged from 8 months to 67 years, but there were only 2 adults (18 and 67 years) in this series. All patients had a murmur which was continuous in 28 cases and systolic in 4 cases. Nine patients had left ventricular hypertrophy on the electrocardiogram and radiological cardiomegaly. Closure of the patent ductus was attempted by Rashkind's technique using a double umbrella of 12 mm diameter for ductus less than 4 mm diameter (26 cases), and an umbrella of 17 mm diameter when the ductus was wider (6 cases). The immediate results judged by retrograde aortography showed total occlusion in 12 patients and incomplete closure in 17 others with persistence of a minimal left-to-right shunt. In 3 cases, embolisation of the umbrella into the left pulmonary artery (2 cases) or right pulmonary artery (1 case), required thoracotomy to extract the umbrella and at the same time section-suture of the ductus arteriosus. Color Doppler echocardiographic follow-up showed the disappearance of the residual shunt in seven children.

Adolescent↗
PubMed1990

[Incidence and factors favouring ventricular arrhythmia after surgical repair of tetralogy of Fallot].

The prevalence and factors favorising postoperative ventricular arrhythmias in 62 patients undergoing surgical repair of tetralogy of Fallot between 1971 and 1982 were analysed. Nineteen patients (31 %) had significant ventricular arrhythmias (Lown greater than or equal to 2) on Holter monitoring or exercise stress testing. The arrhythmia could only be recorded after stress testing in 5 patients. The patient's age at operation, the duration of follow-up and age at evaluation were significantly greater in the group with ventricular arrhythmias. However, age at operation was closely related to the other two parameters and a discriminating analysis showed that the age at operation was not a favorising factor for the occurrence of ventricular arrhythmias (p = 0.23), in contrast to the duration of follow-up (p = 0.0015) and age at evaluation (p = 0.0007). No relationship was found between ventricular arrhythmias and the following factors: previous anastomosis, outflow patch, necessity of a ventriculotomy or reoperation, presence of residual ventricular septal defect, postoperative systolic right ventricular pressure, severity of intraventricular conduction defects, and effort tolerance. These results suggest that after surgical repair of tetralogy of Fallot, the incidence of ventricular arrhythmias increases with time. The main problem is to identify patients with a high risk of sudden death, i.e. those with high degree ventricular arrhythmias and poor haemodynamic results of repair.

Arrhythmias, Cardiac↗
PubMed1990

[Follow-up of surgically treated congenital heart disease using Doppler echocardiography].

Surgery can restore normal cardiac anatomy in some forms of congenital heart disease but in others this is not possible even after a "complete correction". In yet other forms, surgery is only palliative. Echocardiography coupled with pulsed, continuous wave and color coded Doppler should be carried out after clinical, electrocardiographic and radiological examination to assess the surgical results and detect possible complications in the short or long-term. It is therefore important to be familiar with the "normal" appearances of operated congenital heart disease in order to be able to detect postoperative abnormalities. The authors describe the normal postoperative findings for each form of congenital abnormality and the changes which may be observed during Doppler echocardiographic examination. This paper only deals with the more simple malformations: ventricular septal defect, atrial septal defect, atrioventricular canal, patent ductus arteriosus, coarctation of the aorta, aortic stenosis, tetralogy of Fallot and simple transposition of the great vessels.

Aortic Coarctation↗
PubMed1990

[Interventional catheterization in children].

In children, interventional catheterization is performed to treat congenital heart diseases: balloon atrial septostomy; balloon valvotomy for valvar pulmonary stenosis, valvar aortic stenosis, valvar mitral stenosis; balloon angioplasty for venous or arterial stenosis. Transcatheter vascular occlusion can be accomplished using a wide range of devices: transcatheter patent ductus arteriosus closure, embolisation of arteriovenous malformations, systemic-pulmonary collaterals and other extracardiac shunts. Intracardiac or intravascular catheters can be removed.

Angioplasty, Balloon, Coronary↗