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Biomedical subjects

C Rey

Publications and source records attributed to C Rey.

At least 235 records · Page 13Linked to original sources

[Doppler echocardiography after anatomical repair of transposition of great vessels].

Forty seven patients who underwent anatomical repair of transposition of the great arteries were assessed by Doppler Echocardiography on average 16 months after surgery. Thirty three had transposition alone and 14 had an associated ventricular septal defect. Abnormal left ventricular function was observed in 4 patients (8%) and was associated with a preoperative left to right ventricular systolic pressure ratio less than that of patients with normal left ventricular function (0.76 +/- 0.22 vs 0.90 +/- 0.14 respectively, p = 0.10). Aortic regurgitation was detected in 19 children (40%). It was minimal in 18 cases and mild in the other case, in which a ventricular septal defect has been approached via the original pulmonary valves. Previous pulmonary banding before detransposition was a predisposing factor for postoperative aortic regurgitation. Thirteen patients had pulmonary pressure gradients of over 20 mmHg. The site of obstruction was usually the main pulmonary artery. The 3 cases in which the coronary orifices were closed with two patches instead of one had significant stenosis of the main pulmonary artery. Pulmonary regurgitation was detected in 38 patients (81%); it was minimal in 29 cases, mild in 5 cases and severe in 4 cases. Five patients (11%) had minimal mitral regurgitation and 16 (34%) tricuspid regurgitation. In the 22 cases who had serial echocardiographic evaluation with an average follow-up of 18 months, the postoperative abnormalities were characterised by their stability, with no significant progression of the regurgitant lesions. A reduction in pulmonary pressure gradient was observed in 5 patients and an increase in 1 patient (from 28 to 40 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗

[Permanent junctional reciprocating tachycardia in children and adolescents. Efficacy of medical treatment].

Between 1969 and 1991, 11 patients were followed up for permanent junctional reciprocating tachycardia. The average age at diagnosis was 2 years and 4 months (1 day to 14 years). The tachycardia was diagnosed at routine examination in 5 cases and following an episode of cardiac failure in the other 6. Digitalis was prescribed in all patients with 4 good results, 5 average and 2 poor results. One patient, who remained in mild cardiac failure with digitalis therapy, died suddenly at the age of 9 years. In more recent cases, amiodarone was used from the onset or secondarily with good results in all patients. In 2 patients, in whom amiodarone was withdrawn after 3 months and 3 years' treatment, there was a recurrence of the tachycardia. No side effects of amiodarone therapy were observed in this series. Three patients were prescribed flecainide with 1 good and 2 average results. Propranolol, used in 2 cases, was associated with 1 average and 1 poor result. Disopyramide and Verapamil were ineffective. These results suggest that amiodarone is the drug to choose in permanent junctional reciprocating tachycardia but it must be given long term. The persistence of cardiac failure, poor control of the tachycardia or secondary effects of drug therapy should lead to consideration of non-medical management of the tachycardia.

Adolescent↗

[Influence of age and body surface on the signal averaged high amplification ECG after complete repair of tetralogy of Fallot].

The aim of this study was to assess the influence of age and body surface area on the signal averaged ECG after complete repair of Tetralogy of Fallot. Fifty eight patients operated for Tetralogy of Fallot in whom the postoperative ECG showed right bundle branch block without any significant arrhythmia on Holter monitoring or exercise stress testing underwent signal averaged electrocardiography. A very significant relationship was observed between age and body surface area and the duration of the filtered QRS (r = 0.45, p = 0.0004 and r = 0.49, p = 0.00009 respectively) or the average voltage of the last 40 milliseconds (r = -0.49, p less than 0.03 and r = -0.31, p less than 0.02 respectively). Therefore, signal averaged ECG in patients operated for Tetralogy of Fallot varies with age and morphology. An adjustment of the parameters of the signal averaged ECG with respect to clinical characteristics is necessary before assessing the value of this technique for identifying patients at risk of developing ventricular arrhythmias.

Adolescent↗

[Effects of fatty acids on hepatic amino acid metabolism in isolated perfused liver in rats].

Large disparity in experimental conditions concerning the use of isolated perfused liver led us to investigate the effects of two free-fatty acids on amino acid metabolism in this model. Oleate uptake was 210 +/- 46 nmol/min.g and octanoate uptake 550 +/- 60 nmol/min.g. Fatty acid utilization led to an increase in ketogenesis, enhanced by octanoate in accordance with its known availability for beta-oxidation. In our experiments neither oleate nor octanoate modified hepatic amino acid exchange and metabolism as assessed by the measurements of amino acids fluxes and glucose and urea production.

Amino Acids↗

[The 2-chambered right ventricle with an anomalous muscle bundle].

The clinical picture, course, electrocardiogram and chest X-Ray of 30 patients with the angiocardiographic diagnosis of double-chambered right ventricle, along with the echocardiogram in 18 and surgical results in 26 are analyzed. A ventricular septal defect was associated in most of the patients, that had spontaneous closure in some of them. The clinical picture and serial catheterization in some cases suggested progressive obstruction of the right ventricular outflow tract. In this, as in most of the reported series, the history, physical examination, ECG and roentgenogram were inconclusive for diagnosis of this entity. Two-dimensional echocardiography was the most reliable non invasive method to assess this malformation, even superior to catheterization in some aspects. The angiocardiographic findings are quite distinctive, allowing differentiation of other types of subpulmonary stenosis. In order to achieve a good surgical result is essential a precise diagnosis of this malformation and of the associated anomalies. The long-term prognosis was good as in most of the reported series.

Angiocardiography↗

Multicystic dysplastic kidney: absence of complications in patients treated conservatively.

The optimal treatment, surgical or conservative, for multicystic dysplastic kidney (MDK) is still undetermined. We analyzed prospectively the evolution of 12 children with MDK who were managed conservatively. After a mean follow-up of 32 months, the only complication found was an episode of urinary tract infection in 3 patients. Complete involution of MDK was observed in 9 patients (75%), the mean period for sonographical disappearance being 16 months. Infants with MDK should be closely monitored and nephrectomy performed when MDK compresses neighbor organs or hypertension develops. There is no agreement on the best therapeutic approach in patients in whom MDK involution has not occurred after a prudential waiting time still not determined.

Female↗

[Efficacy and acceptability of dexfenfluramine in women consulting in gynecology. 336 overweight patients treated for 3 months].

The efficacy on bodyweight and the acceptability of a three month treatment with dexfenfluramine (Isoméride), combined with a prescribed diet, were evaluated in 336 women followed by a gynecologist for overweight. These women were divided into three groups, those in the sexually active age group (80%) and perimenopausal and post-menopausal women (20%) and had the following characteristics: mean bodyweight 80.2 +/- 0.6 kg; excess bodyweight 35.0 +/- 0.5% of theoretical ideal weight, mean bodyweight index = 30.6 +/- 0.2 kg/m2. Simultaneously with the weight loss, a study of the change in gynecological symptoms was carried out at each consultation and for each group. Investigation of the bodyweight showed that 80% of the patient who followed the treatment for three months lost weight, the mean loss being 7.2 kg or 41.9% of the initial excess weight. Simultaneously with this loss of weight, there was an improvement in the gynecological symptoms in all three groups. These symptoms included those seen in the premenstrual phase (sexually active age group) and menopause-related symptoms in the perimenopausal and post menopausal groups. The acceptability and safety of Isomeride were also confirmed in this study.

Adult↗

[Activity of adenosine deaminase in acute brucellosis and complicated brucellosis].

BACKGROUND: Adenosine deaminase (ADA) is an essential enzyme for the differentiation and proliferation of T lymphocytes and the monocyte-macrophage system. The basic immunitary response of brucellosis is cellular. To this end, ADA activity was evaluated in brucellosis. METHODS: Serum ADA activity was assessed by a colorimetric method in 67 patients with brucellosis, before therapy and at 1, 3 and 6 months of follow up. RESULTS: Serum ADA activity in brucellosis was higher than that in 52 healthy controls, both in those with the acute febrile noncomplicated form (48 patients) and in those with focal symptoms from one organ (19 patients) (p less than 0.0001 and p less than 0.001). There were no differences between both groups of brucellosis. There was a negative correlation between the duration of the disease and ADA activity. After therapy there was a rapid decrease of ADA values, more marked in patients with noncomplicated brucellosis. During the follow up, only one patient had a new increase in ADA activity, coincident with a clinical and bacteriological relapse, and previous to the increase of IgG anti-Brucella titers. CONCLUSIONS: The results indicate that adenosine deaminase activity is increased during the active stage of brucellosis. It can be considered as a biochemical follow up marker of the disease and, probably, as a marker of relapses.

Acute Disease↗

Structural studies of the mineral phase of calcifying cartilage.

The calcified cartilage of the epiphyseal growth plate of young calves has been studied by x-ray diffraction. Fourier transform infrared spectroscopy, magic angle 31P nuclear magnetic resonance spectroscopy, and chemical composition. The powdered tissue was separated by density centrifugation as a function of mineral content and thus qualitatively of the age of the calcium-phosphorus mineral phase. The individual density centrifugation fractions were examined separately. X-ray diffraction of the samples, especially of the lowest density fractions, revealed very poorly crystalline apatite. Fourier transform infrared spectroscopy and 31P nuclear magnetic resonance spectroscopy revealed the presence of significant amounts of nonapatitic phosphate ions. The concentration of such nonapatitic phosphates increases during the early stages of mineralization but then decreases as the mineral content steadily rises until full mineralization is achieved. The total concentration of carbonate ions was found to be much lower in calcified cartilage than in bone from the same organ (scapula). The carbonate ions are located in both A sites (OH-) and B sites (PO4(3-)), with a distribution similar to that found in bone mineral. However, discrepancies between infrared resolution factors of phosphate and carbonate bands are consistent with a heterogeneous distribution of carbonate ions in poorly organized domains of the solid phase of calcium phosphate. These initial studies permit one to characterize the calcium phosphate mineral phase as a very poorly crystalline, immature calcium phosphate apatite, rich in labile nonapatitic phosphate ions, with a low concentration of carbonate ions compared with bone mineral of the same animal, indeed from the bone of the same organ (scapula).

Animals↗

A role for osteocalcin in osteoclast differentiation.

Specific cellular interactions with components of the extracellular matrix can influence cellular differentiation and development of many tissues. The extracellular matrix of bone is composed of organic constituents and a solid phase of calcium and inorganic phosphate (apatite). When implanted subcutaneously in rats, particles of bone matrix (BPs) recruit progenitors that differentiate into multinucleated cells with osteoclastic features. Because BPs deficient in osteocalcin, a bone matrix protein, were less efficient at promoting osteoclast formation than were normal BPs, we directly examined the influence of osteocalcin on osteoclast differentiation. We evaluated tissue responses to particles of synthetic crystalline apatite alone (Ap), having many of the features of native apatite of mature bone, or to apatite prepared with osteocalcin (Ap/OC), bovine serum albumin (Ap/BSA) or rat bone collagen (Ap/Col). Twelve days after subcutaneous implantation in normal rats, Ap, Ap/BSA, and Ap/Col particles generated a mild foreign body reaction with multinucleated cells in direct contact with the particles; these cells were negative for tartrate-resistant acid phosphatase (TRAP) activity and lacked ruffled borders. In contrast, Ap particles containing approximately 0.1% osteocalcin were partially resorbed and they generated more multinucleated cells that were TRAP-positive, were immunoreactive with an antibody against tartrate-resistant purple acid phosphatase, and displayed ultrastructural features of active osteoclasts including ruffled borders and clear zones. These data support the hypothesis that osteocalcin may function as a matrix signal in the recruitment and differentiation of bone-resorbing cells.

Acid Phosphatase↗

The syndrome of renal tubular acidosis and nerve deafness. Discordant manifestations in dizygotic twin brothers.

The syndrome of renal tubular acidosis (RTA) and nerve deafness is a distinct nosological entity that is inherited as an autosomal recessive trait. We studied a pair of dizygotic twin brothers both with nerve deafness but only one with RTA. Distal RTA was diagnosed in twin A because of inappropriately high urinary pH (6.9) and low net acid excretion (40.0 muEq/min per 1.73 m2) in the presence of hyperchloraemic metablic acidosis, and fractional bicarbonate excretion of 1.6% at a normal serum bicarbonate concentration. The urine minus blood PCO2 differences (U-B PCO2) during a neutral sodium phosphate load and in alkaline urine induced by bicarbonate supplementation were: 11 and 0 mm Hg, respectively. Twin A developed nephrocalcinosis and, after a 9.5-year follow-up period, was 5.3 cm taller than his brother. Twin B remained asymptomatic. Periodic determinations of blood pH and serum bicarbonate were normal and urine pH decreased to 4.6 in the face of ammonium chloride-induced metabolic acidosis. The U-B PCO2 assessed in alkaline urine was 33.5 mm Hg. Audiograms demonstrated bilateral nerve deafness in both brothers. The presence of deafness without RTA has not been previously reported in this syndrome. This report also shows that a primary distal acidification defect is responsible for the RTA observed in this syndrome.

Acidosis, Renal Tubular↗

Resolution-enhanced Fourier transform infrared spectroscopy study of the environment of phosphate ion in the early deposits of a solid phase of calcium phosphate in bone and enamel and their evolution with age: 2. Investigations in the nu3PO4 domain.

Resolution-enhanced Fourier Transform Infrared (FTIR) spectra of early mineral deposits in enamel and bone show bands at 1020, 1100, 1110, 1125, and 1145 cm-1 in the nu3PO4 domain which do not belong to well crystallized stoichiometric hydroxyapatite. Bands at 1020 and 1100 cm-1 have been shown to occur in nonstoichiometric apatites containing HPO4(2-) ions and the weak band at 1145 cm-1 has been assigned to HPO4(2-) ions. Though the bands at 1110 and 1125 cm-1 have not been found in any well crystallized apatite, they are present in newly precipitated apatite. These latter bands disappear progressively during maturation in biological as well as synthetic samples, and partial dissolution of synthetic apatites shows that they belong to species that exhibit an inhomogeneous distribution in the mineral, and that are the first to be solubilized. Comparison of the FTIR spectra of biological apatites with those of synthetic, nonapatitic-containing phosphate minerals shows that the presence of these bands does not arise from nonapatitic, well-defined phases; they are due to the local environment of phosphate ions which may possibly be loosely related or perhaps unrelated to the phosphate groups present in the well-crystallized nonapatitic calcium phosphates. Resolution-enhanced FTIR affords a very precise characterization of the mineral phases which may be very useful in characterizing pathological deposits of Ca-P mineral phases.

Animals↗

Fourier transform infrared spectroscopic study of the carbonate ions in bone mineral during aging.

The environment of CO3(2-) ions in the bone mineral of chickens of different ages and in bone fractions of different density have been investigated by resolution-enhanced Fourier Transform Infrared (FTIR) Spectroscopy. Three carbonate bands appear in the upsilon 2 CO3 domain at 878, 871, and 866 cm-1, which may be assigned to three different locations of the ion in the mineral: in monovalent anionic sites of the apatitic structure (878 cm-1), in trivalent anionic sites (871 cm-1), and in unstable location (866 cm-1) probably in perturbed regions of the crystals. The distribution of the carbonate ions among these locations was estimated by comparing the intensities of the corresponding FTIR spectral bands. The intensity ratio of the 878 and 871 cm-1 bands remains remarkably constant in whole bone as well as in the fractions obtained by density centrifugation. On the contrary, the intensity ratio of the 866 cm-1 to the 871 cm-1 band was found to vary directly and decreased with the age of the animal. In bone of the same age, the relative content of the unstable carbonate ion was found to be highest in the most abundant density centrifugation fraction. A resolution factor of the CO3(2-) band (CO3 RF) was calculated from the FTIR spectra which was shown to be very sensitive to the degree of crystallinity of the mineral. The crystallinity was found to improve rapidly with the age of the animal. The CO3 RF in the bone samples obtained by density centrifugation from bone of the same animal was found to be essentially constant.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

A resolution-enhanced Fourier transform infrared spectroscopic study of the environment of the CO3(2-) ion in the mineral phase of enamel during its formation and maturation.

A resolution-enhanced Fourier Transform Infrared (FTIR) Spectroscopic study of the CO3(2-) ion in pig enamel of increasing age and maturity has demonstrated the existence of four different, main carbonate locations. The major CO3(2-) site arises as a result of the substitution of CO3(2-) ions in the positions occupied by PO4(3-) ions in the apatitic lattice. In addition, two minor locations have been identified in positions in which the CO3(2-) ions substitute for OH- ions. The fourth carbonate group appears to be in an unstable location. Its concentration has been found to decrease with aging and maturation, during which there is a progressive increase in the amount of mineral deposited in the enamel. The distribution of the carbonate ions in the different apatitic sites varies randomly during the formation of the mineral phase in enamel and during its maturation. Although these changes have been shown to be related to changes in the composition of the mineral phase, a comparison of the parameters assessing the degree of crystallinity of the mineral phase from upsilon 2CO3(2-) and upsilon 4PO4(3-) infrared absorption data reveals a significant discrepancy related to the nonhomogeneous partition of the CO3(2-) ion in the mineral phase. After maximum mineralization is reached, the composition of the mature mineral phase is decidedly different than that of the initial mineral deposited; the changes affect principally the concentrations of Ca2+, OH-, and HPO4(2-) ions, but not the CO3(2-) ions.

Aging↗

Carbonate ions in apatites: infrared investigations in the upsilon 4 CO3 domain.

Fourier transform infrared (IR) spectroscopic investigations of precipitated carbonate apatites in the upsilon 4 CO3 domain reveal the existence of five bands at 757, 740, 718, 692, 670 cm-1 which can be assigned to several distinct environments of the carbonate ion in the apatite structure. In order to identify these environments precisely, fluoridated and pure type A carbonate apatites (i.e., with carbonate ions in monovalent anionic sites) were examined. The bands at 670 and 757 cm-1 were attributed to type A carbonate and their relative intensity was found to increase when the carbonate content of the apatite diminished or when samples were heated at 400 degrees C. Fluoridated apatites show only two bands, close to 718 and 692 cm-1, corresponding to type B carbonate ions (carbonate in trivalent anionic sites). The band at 740 cm-1 was revealed by heating the samples to 400 degrees C. This is due to OH ions' hydrogen bonded to fluoride and to carbonate ions in an undetermined apatite site. Despite the low intensity of IR bands, investigations in the upsilon 4 CO3 domain appear complementary to those in other carbonate vibrational domains and could be useful for a more precise identification of bone mineral.

Apatites↗

Effect of bile acids on ischemia-reperfusion liver injury.

We investigated whether stimulation of bile flow by taurocholic acid (TCA), ursodeoxycholic acid (UDCA) or its taurine conjugate (TUDCA) could protect the liver from ischemia-reperfusion injury. The isolated perfused rat liver model was used. In livers perfused without bile acids (n = 8), 60 min of ischemia induced a significant reduction in bile flow and in portal flow, together with a marked increase in LDH, AST and uric acid release in the perfusate. These alterations were maximal at the beginning of reperfusion. In livers perfused with TCA (n = 6), UDCA (n = 7) or TUDCA (n = 6), bile flow was significantly increased as compared to controls during the pre-ischemic phase, as well as during the reperfusion phase. However, no significant improvement was observed in any of the biochemical, hemodynamic or histologic parameters studied. The results show that stimulation of bile flow either by TCA, UDCA or TUDCA does not reduce ischemia-reperfusion liver injury. Furthermore, the results do not provide evidence for a cytoprotective effect of UDCA or TUDCA in this model of liver injury.

Animals↗