Search PubMed⌕ Search

Biomedical subjects

C Rey

Publications and source records attributed to C Rey.

At least 163 records · Page 9Linked to original sources
PubMed1996

Characterization of the apatite crystals of bone and their maturation in osteoblast cell culture: comparison with native bone crystals.

Calcium phosphate crystals deposited in the organic matrix synthesized by chick bone osteoblasts in culture were studied by x-ray and electron diffraction, Fourier transform infrared spectroscopy and chemical composition. The amounts of mineral phase deposited with time and the extent of calcification (% of mineral phase in the tissue) were also determined as a function of time, as were the nature of the changes in the short range order of the crystals. The amount of mineral deposited and the extent of calcification increased with time; the tissue not only contained more crystals of apatite, but the extent of calcification also increased with time as it does in vivo. After 30 days of culture the extent of calcification in the cell culture matrix was similar to that in late chick embryonic and early postnatal chick tibiae. The nature of the CO3 and HPD4 environments were similar to those found in vivo although the concentrations of these ions and the changes in their concentrations with time appeared to develop more slowly in cell culture than they do in vivo. However, the general overall pathway of maturation was similar in cell culture to that observed in vivo.

Animals↗
PubMed1996

A pilot case-control study of zidovudine compared with zidovudine plus didanosine in patients with advanced HIV-1 disease and no previous experience with antiretrovirals.

Although zidovudine (ZDV) is effective in HIV-1-infected patients, the duration of its efficacy may be short when treatment is started in advanced HIV disease. This pilot prospective case-control study was designed to evaluate the combination of ZDV plus didanosine [ddI] compared with ZDV monotherapy as an initial therapeutic strategy. 'Control' patients (ZDV monotherapy) were matched with 'case' patients (ZDV plus ddI combination therapy) according to the presence or absence of AIDS-defining criteria at entry and CD4 cell count. The case patient group consisted of 35 consecutive HIV-1-infected individuals with < or = 300 CD4 cells/mm3, no previous experience of antiretroviral therapy and who accepted treatment with a combination of ZDV plus ddI. The control patient group consisted of 35 consecutive patients with similar characteristics, but who preferred to start treatment with ZDV alone. Control patients received 250 mg ZDV bid and case patients received ZDV at the same dose plus ddI (200 mg bid). Primary study endpoints were virological (serum HIV-1 RNA) and immunological (CD4 cell count) responses. Viral phenotype (syncytium-inducing (SI) or non-syncytium-inducing (NSI)), development of mutations at codons 215, 41 and 74 and clinical progression (new AIDS-defining event or death) were also assessed. Virological and CD4 cell count responses were significantly greater and more sustained in the group treated with ZDV plus ddI than in the control group, with peak responses of -1.2 +/- 0.7 log10 versus -0.3 +/- 0.4 log10 at 1 month (P = 0.0003) and 61 +/- 52 cells/mm3 versus 19 +/- 25 cells/mm3 at 2 months (P = 0.001), respectively. In both groups the percentage of patients developing a mutation at codon 215 was around 80 per cent at 12 months. A mutation at codon 74 was detected in 30 per cent of case patients at 12 months. Five case patients (14 per cent) versus 12 control patients (34 per cent) showed signs of clinical progression (P = 0.09). In a multivariate model, clinical progression was significantly associated with a baseline

Adult↗
PubMed1996

Assessment of protein intake in children with chronic renal insufficiency.

Daily nitrogen intake was estimated in 19 children, aged (mean +/- SD) 9.9 +/- 5.0 (range: 1-19) years with chronic renal insufficiency (creatinine clearance 47.1 +/- 19.3 ml/min/1.73 m2, range: 11-75) by 31 three-day prospective dietary records (NIDR) and simultaneous 24-hour urine urea excretion (NIUE). Daily nitrogen intake was 11.05 +/- 3.9 g by NIDR and 8.52 +/- 3.3 g by NIUE, and a significant correlation (r = 0.61; p = 0.0003) existed between both methods of measurement. However, the difference in nitrogen intake estimated from dietary records and from 24-hour urine collection (NIDR-NIUE) was 2.5 +/- 3.3 g, greater than the mean estimated nitrogen intake calculated from both methods, (NIDR + NIUE)/2, 95% limits of agreement being +9.1 to -4.1. Thus, NIDR and NIUE values show a good correlation in children with chronic renal insufficiency, although both methods may provide quite a different estimation in a given child.

Adolescent↗
PubMed1996

Analysis of growth in five-sixths-nephrectomized rats.

The present study was designed in an attempt to better define the pattern of growth in five-sixths-nephrectomized rats. Male Sprague-Dawley rats underwent two-stage (days 0 and 7) five-sixths nephrectomy (NX, n = 16) or sham surgery (SHAM, n = 9). At the time of sacrifice (day 21), renal failure (CRF) of NX rats was confirmed by elevated (p < or = 0.0001) serum concentrations (X +/- SEM) of urea nitrogen (SUN) (56 +/- 5 vs. 20 +/- 1 mg/dl) and creatinine (0.7 +/- 0.04 vs. 0.4 +/- 0.02 mg/dl) and reduced SUN (0.13 +/- 0.02 vs. 0.44 +/- 0.05 ml/min/100 g) and creatinine clearances (0.23 +/- 0.02 vs. 0.58 +/- 0.05 ml/min/100 g). As shown by lower cumulative gains of weight (41 +/- 6 vs. 74 +/- 4 g) and length (5.0 +/- 0.4 vs. 6.8 +/- 0.3 cm), NX rats grew subnormally. Detailed analysis of growth data revealed: (1) In spite of being identically matched in weight and length on day 0, at day 7, NX rats already weighed less than SHAM animals (147.1 +/- 2.3 vs. 153.4 +/- 1.9 g, p = 0.03). (2) From day 7 on, daily gain of weight was lower in the NX group only on days 8 (-6.08 +/- 0.52 vs. -1.60 +/- 0.69 g/100 g body weight) and 9 (-0.41 +/- 1.73 vs. 5.18 +/- 0.63 g/100 g body weight). (3) Following the early post-second-nephrectomy period, two subgroups of NX rats were clearly differentiated according to whether or not their daily growth rate was lower than that of SHAM animals. Maintained subnormal growth rate was observed in rats with severe CRF (SUN 73 +/- 5 mg/dl, range 54-90) but not in rats having milder uremia (42 +/- 3 mg/dl, range 31-51). Thus, growth in five-sixths-nephrectomized rats should be reported based on daily weight increments (g/100 g body weight). Subnormal growth can be attributed to CRF provided SUN is at least 3 times as high as normal while growth impairment of rats with less marked reduction of renal function is likely related to transient acute renal failure and postsurgical catabolic state.

Animals↗
PubMed1996

[French experience in the closure of atrial septal defects of the ostium secundum type with the Sideris button occluder].

From February 1992 to November 1995, four French teams used the Sideris button occluder to close 122 ostium secundum, foramen ovale or surgical fenestration atrial septal defects in 121 patients aged 2 to 79 years with body weights of 10 to 96 kg. a left-to-right shunt in 110 cases (average QP/QS = 2.09) or right-to-left shunt in 12 cases. The usual type of prosthesis was used in 115 cases, 8 centered on a guide wire, reverse type in 5 cases and the "centering-device" type in 2 patients. Nineteen implantation attempts were abandoned before releasing the prosthesis. The immediate results were: closure of the atrial septal defect in 116 patients: 59 were completely occluded, 43 had minimal residual shunts. Five patients were operated for non-buttoning or malposition of the prosthesis. In one other case, the device was removed by catheterisation. During follow-up ranging from 1 month to 3 years, 20 patients were operated for varying complications, the commonest of which was malposition of the prosthesis (17 cases) with a shunt of variable volume. In one other case, a second device was inserted. Seventy-seven patients were reviewed at 1 year, 28 a 2 years and 6 at 3 years. The residual shunts decreased with time but only completely disappeared in half the cases. Secondary fractures not requiring surgery were observed in 5 patients. Failures and complications were the result of various causes which are discussed. Successive technological improvements and the experience of the medical teams should reduce this incidence, but caution is required especially in the treatment of young children.

Adolescent↗
PubMed1996

[Percutaneous implantation of endoprostheses in stenosis of the pulmonary branches].

Between July 1992 and October 1995. 10 Palmaz stents were implanted in 6 patients aged 2 to 25 years with stenoses of pulmonary artery branches. The stenoses were located on the right (n = 2) or left pulmonary artery (n = 3) or both branches (n = 1). Stenoses of the right pulmonary artery were secondary to a Waterston (n = 1) or Blalock-Taussig (n = 1) anastomosis or to surgical plasty with Dacron (n = 1). Stenoses of the left pulmonary artery were secondary to surgical plasty with Goretex (n = 2), pericardium (n = 1) or Dacron (n = 1): three of these patients had undergone a left Blalock-Taussig anastomosis before complete correction. After implantation of the stent, the pulmonary artery diameter increased from 4 +/- 2 mm to 11 +/- 2 mm (p = 0.0117) and the transstenotic gradient decreased from 44 +/- 18 to 15 +/- 12 mmHg (p = 0.0277). Similarly, the percentage of homolateral pulmonary perfusion at scintigraphy increased from 22 +/- 13% to 53 +/- 17% (p = 0.0431). There were no deaths. The major complication was migration of the stent, observed in three patients at the moment of implantation in two cases and in the hours following implantation in the other case. In these 3 patients, the embolised stent was left in the pulmonary arteries with no adverse consequences on pulmonary perfusion. Two of these patients later successfully underwent further catheterisation for implantation of another stent. Implantation of a stent is a therapeutic alternative in pulmonary artery stenoses which often recur after surgery and/or angioplasty. They increase the diameter of the stenosed vessel and reestablish the equilibrium of perfusion between the two lungs.

Adolescent↗
PubMed1996

[Percutaneous valvotomy of aortic valve stenoses in children].

A retrospective cooperative study of percutaneous aortic valvuloplasty was undertaken in 12 French centres from 1985 and included 90 children over 3 months of age (average 8.5 +/- 5.2 years) treated for isolated aortic valve stenosis with peak transvalvular pressure gradients of 80.7 +/- 23 mmHg. over 50 mmHg in 92% of cases. The majority of cases were performed by a retrograde femoral arterial approach with inflation of a balloon with a diameter approximating that of the aortic annulus. There was one serious complication (lethal collapse occurring before dilatation) and 12% of local complications due to arterial trauma: the latter were temporary or accessible to simple therapeutic measures. Overall, the pressure gradient decreased by an average of 39.2 +/- 25.4 mmHg. There were 15 immediate failures (17%) and 21 partial results (23%) requiring a further procedure at varying intervals after the valvuloplasty. There were 54 primary successes (60%) with annulation of the pressure gradient and this result was sustained in 45 of the 51 cases followed up for an average of 34 +/- 21 months. Aortic regurgitation was observed or aggravated in 29 children; at the end of the study, this remained a serious problem in 15 cases (17%). The authors conclude that interventional catheterisation is an elegant. simple and relatively economical alternative to conventional surgery. It is as safe, but less immediately effective overall; aortic continence may be compromised in the long-term. In the absence of technical innovations, a parallel development of the two therapeutic procedures is to be expected.

Adolescent↗
PubMed1996

[Percutaneous pulmonary valvuloplasty in neonates and infants with tetralogy of Fallot].

Percutaneous pulmonary valvuloplasty remains controversial as a palliative procedure in Tetralogy of Fallot. This paper reports the results of this technique with respect to clinical improvement and growth of the pulmonary arterial tree. Between June 1990 and July 1995, valvuloplasty with a balloon catheter was performed in 25 neonates or infants with Tetralogy of Fallot (13 girls and 12 boys). All patients were symptomatic with severe cyanosis associated with anoxic malaise in 14 cases. At catheterisation, the children were aged 3.5 +/- 2.6 months and weighted 4.7 +/- 1.2 kg. After dilatation, cutaneous oxygen saturation increased from 75 +/- 11 to 88 +/- 8% (p = 0.001). However, 3 children were referred for early surgery (one complete correction and two systemico-pulmonary anastomoses because of persistent desaturation. There were no lethal complications. A control (catheterisation or surgery) allowed evaluation of the growth of the pulmonary tract, on average 5.5 +/- 4.3 months after dilatation. The pulmonary artery diameter increased from 6.17 +/- 1.26 mm to 8.66 +/- 1.22 mm (p = 0.0015). Expressed as a Z score, the annulus diameter changed from -3.93 +/- 0.91 to -2.54 +/- 1.2 SD (p = 0.0019). The mean Z score of the right pulmonary artery increased from -3.01 +/- 0.69 to -1.98 +/- 1.12 SD (p = 0.0251) and the Z score of the left pulmonary artery from -2.68 +/- 0.85 to -1.61 +/- 1.46 SD (p = 0.0357). At complete correction, 50% of patients had had correction of their malformation without section of the pulmonary annulus. In conclusion, pulmonary valvuloplasty in Tetralogy of Fallot enables growth of the annulus and pulmonary arteries and is a valuable alternative to palliative systemico-pulmonary anastomosis.

Blood Gas Analysis↗
PubMed1996

[Double outlet left ventricle: a rare and unusual cardiopathy. Apropos of 7 new cases].

Double outlet left ventricle is a very rare condition due to an abnormality of conotruncal morphogenesis. The authors report 7 new cases to the 119 already published, one with an anatomical variation not previously described. Three of the cases reported were of the most usual type similating tetralogy of Fallot. Two of these cases underwent complete correction with excellent results 13 months and 2 years after surgery. The third patient aged 6 months is well after initial palliative neonatal surgery. A case with an L-malposition pedicle with subpulmonary ventricular septal defect and pulmonary outflow tract obstruction died after early palliative surgery (Blalock-Taussig). A case with subaortic ventricular septal defect, pulmonary stenosis, and tricuspid atresia, underwent physiopathological correction (Fontan procedure) after a Waterston shunt and is well at 19 years of age. The other two cases presented more unusual anatomical forms aortic outflow obstruction: one had hypoplasia of the aortic arch with an isthmic coarctation requiring a Crafoord procedure in the neonatal period associating with banding followed by complete correction at 19 months of age. After 3 years, the patient is asymptomatic. The last case with atresia of the aortic valve and severe hypoplasia of the ascending aorta died after corrective surgery of first intent. Other cases have been described in the literature with different clinical presentations: absence of pulmonary or aortic obstruction; intact interventricular septum. The anatomical variability is due to the complex embryogenesis of the conotruncal region and explains the clinical diversity of this congenital cardiac malformation.

Aortic Valve↗
PubMed1996

[Cardiac involvement in Kugelberg-Welander disease. A prospective study of 8 cases].

Kugelberg-Welander disease is a juvenile form of slowly progressive spiral amyotrophy in which the incidence of cardiac involvement is difficult to appreciate as cases are sporadic. Classically, it presents with atrial hyperexcitability with variable degrees of atrioventricular block. In order to assess the prevalence of cardiac involvement in this condition, the authors undertook a prospective study in 8 patients with Kugelberg-Welander disease. All underwent clinical and paraclinical examinations to assess cardiac function and rhythm. Doppler echocardiography, myocardial scintigraphy with Thallium 201 and Technetium99m, resting ECG. 24 hour Holter monitoring and signal averaged ECG were performed in all cases. This unique study detected one patient with infraclinical disease of the conduction system who became symptomatic during the follow-up period and required definitive cardiac pacing. During the study, one 20 year old man with Kugelberg-Welander disease was admitted to hospital with dilated cardiomyopathy with a fatal outcome. Because of the small number of patients and after a review of the literature, this study is to be continued to obtain a more accurate evaluation of cardiac involvement in this neuromuscular disease.

Adolescent↗
PubMed1996

[Pulmonary vein stenosis. Description of a sutureless surgical procedure using the pericardium in situ].

Pulmonary vein stenosis is a rare cardiac disease associated with a disastrous prognosis. Nowadays, it is more often a iatrogenic complication, following neonatal surgical repair of total anomalous pulmonary venous drainage (TAPVD). It is as well a native congenital anomaly. The responsible histologic lesion is an intimal hyperplasia that proliferates to involve the extracardiac segment of the pulmonary veins. This lesion tends to be extremely recurrent following surgical or angioplastic attempts. A new sutureless surgical technique, that tunelizes the pulmonary veins to the left atrium through the pericardium, is described. This method was successfully applied in a 2.5 years old child, presenting with bilateral stenosis of pulmonary veins, following neonatal repair of a TAPVD. The result, controlled 6 months later, by catheterization and angiography was judged satisfactory. This new technique, that has to be confirmed by a longer follow up, may provide a therapeutic answer to this challenging disease.

Angiocardiography↗
PubMed1996

[Hyperplastic gastric polyposis and familial colonic adenomas. Apropos of a case].

A case of gastric hyperplastic polyposis is reported in a 48-year old woman, with iron deficiency anemia. An hyperplastic gastric polyposis was discovered. This patient had been operated 17 years previously for a large adenomatous polyp of the caecum. Her son had also several adenomatous polyps of the right colon. A gastrectomy was performed. Hyperplastic gastric polyposis is very rare, and is quite always associated with colorectal adenomas. The relationship between gastric hyperplastic polyposis and intestinal polyposis is not quite clear.

Adenomatous Polyps↗
PubMed1995

Structural and chemical characteristics and maturation of the calcium-phosphate crystals formed during the calcification of the organic matrix synthesized by chicken osteoblasts in cell culture.

The calcium-phosphate (CA-P) crystals formed in the extracellular organic matrix synthesized by chicken osteoblasts in cell culture were examined after 30, 40, and 60 days of culture by a number of physical and chemical techniques including chemical analyses, X-ray diffraction, transmission electron microscopy of isolated crystals, and resolution-enhanced Fourier transform infrared spectroscopy. The data reveal that the solid inorganic calcium-phosphate phase consists of a very poorly crystalline apatite, having a low carbonate content and containing acid phosphate groups. The chemical and structural characteristics are generally similar to the apatite crystals found in young newly synthesized bone but there were small but significant differences found. The major significant differences noted were the rate at which maturational changes occurred in the crystals formed in cell culture compared with those noted in vivo and in synthetic carbonate apatite crystals equilibrated with the same cell culture medium, and the persistence of labile groups, especially HPO4(-2) ions during a relatively long period of incubation. Despite extensive chemical efforts to degrade the organic constituents and to disperse the individual crystals isolated from the organic matrix constituents, a large proportion of the crystals were found to be organized in both loosely and densely packed relatively large roughly spherical aggregates. A few of the aggregates were organized in the form of fibrils with the crystals oriented with their c-axes roughly parallel to the long axes of the crystal aggregate. With briefer periods of chemical treatment, larger aggregates of crystals were occasionally observed in which there was a distinct axial periodicity of approximately 70 nm. In such collagen-crystal fragments, the crystals were well-oriented with their c-axis roughly parallel to the long axes of the aggregate similar to the organization and relationships between crystals and collagen fibrils in native bone. Isolated crystals were in the shape of thin plates. At the end of 30 days of culture, many of the crystals were clearly larger than those observed in native chick bone, except for those in the very youngest (7- to 8-day-old) embryos. At the end of 40 and 60 days of culture, the crystal habit remained as thin plates but the crystals were predominantly smaller, similar to those found in older embryo and postnatal chicken bone. The marked tendency of the crystals to form relatively large aggregates that resist dispersion by techniques that readily disperse the crystals of bone, and the presence of a significant number of larger crystals has also been observed in studies of calcified cartilage. Resolution enhanced FTIR spectroscopy revealed the presence of a high concentration of labile phosphate groups, especially after 30 days of culture and just after the plateau of mineralization is reached.

Animals↗
PubMed1995

Isolation of calcium-phosphate crystals of bone by non-aqueous methods at low temperature.

We have developed low temperature nonaqueous solution methods as well as low power plasma ashing for the degradation of the organic matrix of bone power which have permitted us to obtain bone crystals essentially free of organic matrix constituents without any significant change in their composition, overall structure, or internal short-range order. We have also been able to disperse the crystals, which has made it possible to examine the isolated crystals by X-ray diffraction and resolution-enhanced Fourier transform infrared (FTIR) spectroscopy and isolated single crystals by high resolution transmission electron microscopy (TEM) and electron diffraction. TEM of isolated single crystals of fish, chicken, mouse and bovine bone have clearly demonstrated that the crystals are very thin plates. No rod or needle-like crystals were observed in any of the bone samples in the four species studied including the earliest crystals deposited. Although there were variations in the size distribution of the crystals in the different species studied, in general the average crystal dimensions were very similar.

Animals↗
PubMed1995

Nutritional status of children with moderate chronic renal failure.

Nutritional status was evaluated in 15 children (11 males) with moderate chronic renal failure (CRF). Two 3-day prospective dietary records, anthropometric measures and biochemical determinations were performed 3 months apart. Energy, protein, carbohydrate, fat, polyunsaturated, monounsaturated and saturated fatty acid intakes, expressed as percentages of international recommendations, were 87 +/- 14, 223 +/- 42, 73 +/- 12, 110 +/- 27, 55 +/- 31, 129 +/- 51 and 111 +/- 26%, respectively. The relative distribution of calories was 15 +/- 2% from proteins, 48 +/- 5% from carbohydrates and 37 +/- 5% from lipids. Anthropometric indices, expressed as standard deviation score, were: weight -0.50 +/- 0.8, height -0.94 +/- 1.3, growth velocity -0.61 +/- 1.8, triceps skinfold thickness -0.30 +/- 0.6, subscapular skinfold thickness -0.19 +/- 0.8, mid-arm muscle circumference 0.38 +/- 0.3 and body mass index -0.22 +/- 1.0. Serum concentrations of albumin, total protein, transferrin, IgG, IgA, IgM, C3 and C4 and blood lymphocyte counts were within normal limits. The mean serum insulin-like growth factor-I concentration, expressed as standard deviation score, as 0.74 +/- 1.5. No anthropometric or biochemical signs of malnutrition were found in children with moderate CRF. However, their dietary intake of calories and carbohydrates was low and the protein and saturated fatty acid intake excessively high.

Adolescent↗