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R Dumas

Publications and source records attributed to R Dumas.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Contribution of magnetic resonance imaging in sclerotic combined degeneration of the spinal cord due to vitamin B12 deficiency].

Subacute combined degeneration (SCD) of the spinal cord is known to present histopathologically degenerative lesions in the spinal cord, but few studies on the neuroradiological findings have so far been reported. We present the interest of initial and follow-up MR findings in three cases of SCD. In the three cases, a causal event precipitated the onset of neurological symptoms: general anesthesia for the first and the third one and folic acid treatment for the second one. Clinical evolution was favorable after specific treatment with nearly total recovery. The initial MR study disclosed lesions predominantly involving the posterior columns of the spinal cord: high intensity on T2 weighted image was seen in the initial MR study and disappeared three months after treatment in correlation with good recovery, but with a delay. The recognition of this MR pattern suggests that MRI may be used in conjunction with clinical assessment to confirm the diagnosis and to monitor the efficacity of treatment in SCD.

Aged↗
PubMed1999

Safety, immunogenicity and antibody persistence of an inactivated hepatitis A vaccine in 4 to 15 year old children.

Among 277 healthy Venezuelan children, aged between 4 and 15 years, who were screened for hepatitis A virus (HAV) antibodies, 118 seronegative children were enrolled in an open study. Each child received one dose of the Pasteur Mérieux Connaught inactivated hepatitis A vaccine (AVAXIM¿trade mark omitted¿, 160 antigen units), followed by a booster dose 24 weeks later. All seronegative subjects seroconverted 2 weeks after immunisation (antibody titres greater, similar20 mIU/ml), and antibody titres were still over greater, similar20 mIU/ml after 24 weeks, at the moment of the booster dose. The anti-HAV antibody geometric mean titre (GMT), as measured by a modified radio-immunoassay (HAVAB(R), Abbott Laboratories, North Chicago, IL, USA), was 73.7 mIU/ml, 2 weeks after the first dose. Four weeks after the booster, the GMT value reached 6999 mIU/ml, representing a 29.6-fold rise from pre-booster levels. One year after the booster dose, the GMT value was 1673 mIU/ml in the 92 subjects who provided blood samples at this time, all of whom were still seroconverted ( greater, similar20 mIU/ml). No serious adverse event related to the vaccination occurred during the study. No immediate systemic reaction occurred. Local reactions were reported by 9.3% of subjects who received the primary injection and 5.5% of those given the booster dose. The systemic reactions were mainly fever and myalgia reported over the 7 days following the injection by 3.4% of subjects after the first dose and 5.5% of subjects after the booster dose. A clinically significant elevation of serum transaminase from pre-immunisation levels was noted in one subject (AST level 2.2 times the upper normal limit) 2 weeks after the first injection, although this was not associated with any clinical signs of impaired liver function. This trial demonstrated that AVAXIM¿trade mark omitted¿ containing 160 antigen units is safe and highly immunogenic in healthy children aged between 4 and 15 years, and could be included in the childhood vaccination schedule to control infection in areas endemic for hepatitis A.

Adolescent↗
PubMed1999

Characterization of the conformational changes of acetohydroxy acid isomeroreductase induced by the binding of Mg2+ ions, NADPH, and a competitive inhibitor.

Acetohydroxy acid isomeroreductase (EC 1.1.1.86), the second enzyme of the parallel branched chain amino acid pathway, is a homodimer with an Mr of approximately 114000 which in the presence of Mg2+ ions catalyzes an unusual alkyl migration followed by an NADPH-dependent reduction. Prior binding of NADPH and Mg2+ to the enzyme was shown to be required for substrate or competitive inhibitor [N-hydroxy-N-isopropyloxamate (IpOHA)] binding [Dumas, R., et al. (1994) Biochem. J. 301, 813-820]. Moreover, crystallographic data for the enzyme-NADPH-Mg2+-IpOHA complex [Biou, V., et al. (1997) EMBO J. 16, 3405-3415] have shown that IpOHA was completely buried inside the active site. These observations raised the question of how the reaction intermediate analogue inhibitor can reach the active site and implied that conformational changes occurred during the binding process. With a view of characterizing these conformational changes, H-D exchange experiments combined with mass spectrometry were performed. Results demonstrated that Mg2+ ions and NADPH binding led to an initial conformational change at the interface of the two domains of each monomer. Binding of the two cofactors to isomeroreductase alters the structure of the active site to promote inhibitor (substrate) binding, in agreement with the ordered mechanism of the enzyme. Structural changes remote from the active site were also found. They were interpreted as long-range structural effects on the two domains and on the two monomers in the time course of the ligand binding process.

Alcohol Oxidoreductases↗
PubMed1999

Safety and immunogenicity of a new formulation of an inactivated hepatitis A vaccine.

The safety and immunogenicity of a new formulation of the inactivated hepatitis A vaccine, Avaxim, was evaluated in 189 children, aged 18 months to 15 years in a monocentric, open trial. Two vaccinations were given six months apart. Enrollment was balanced within three age groups: 18 months to 3 years, 4-8 years and 9-15 years. Antibody titers were measured blindly by an independent laboratory using a modified radioimmunoassay. Two weeks after the first dose, seroconversion was achieved by 94.6, 94.3 and 96.4% of initially HAV-seronegative subjects (antibody titre <20 mIU/ml) in each age group (youngest to oldest, respectively), with corresponding geometric mean titre concentrations (GMC) of 72.2, 54.3 and 47.1 mIU/ml. Just before the booster dose, the seroconversion rate was 100% in all groups, and the corresponding GMC values were 163, 169 and 111 mIU/ml. All groups included, a 22.6-fold rise in GMC from prebooster levels was observed four weeks after the booster dose. An explanatory analysis suggested a tendency for higher antibody levels in younger children at all vaccination time points. Local reactions were noted in 18.2% of the vaccinees after the first dose and in 8.5% after the booster dose. The rates of systemic reactions were 23.8% after the first dose and 11.4% after the booster dose. Overall, this trial demonstrated the good safety and immunogenicity profile of this vaccine in children aged 18 months to 15 years of age.

Adolescent↗
PubMed1999

The same mutation affecting the splicing of WT1 gene is present on Frasier syndrome patients with or without Wilms' tumor.

Denys-Drash and Frasier syndromes are rare human disorders that associate nephropathy with gonadal and genital abnormalities. In DDS there is a predisposition to Wilms' tumor. Heterozygous point mutations in the Wilms' tumor, type1 gene (WT1), particularly those altering the zinc finger (ZF) encoding exons, have been reported in most DDS patients, while mutations in intron 9 of the same gene cause FS. This paper describes two cases of DDS, one FS and one patient with Wilm's tumor and intersex genitalia, in which mutations were searched by sequencing the exons 8 and 9 of WT1 gene. Patient 1 carried a missense point mutation in exon 8 (ZF2), converting a CGA-Arg codon to a TGA-stop codon. Patient 2 presented a single nucleotide deletion within exon 9 (ZF3) introducing a premature chain termination at codon 398. Patients 3 and 4 had a C-->T transition at position +4 of the second alternative splice donor site of exon 9 (this mutation was detected in peripheral blood and in tumor derived DNA of patient 3). However, patient 3 had previously developed a Wilms' tumor. This is the first case of Wilms' tumor development in a phenotypically and genetically confirmed case of FS.

Adolescent↗
PubMed1999

Comparison of ultrasound and dimercaptosuccinic acid scintigraphy changes in acute pyelonephritis.

The strategy for morphological investigations in children with acute pyelonephritis (APN) remains debatable. We studied 70 children (median age 2.0 years) admitted with a first episode of pyelonephritis using a high-resolution ultrasound technique (RUS) and compared the results with 99m technetium-dimercaptosuccinic acid (DMSA) renal scintigraphy. The DMSA scan was abnormal in 62 children (89%). However, using a high-frequency transducer we found abnormal sonogram changes in 61 children (87%), consisting of an increased kidney volume in 42, and/or a thickening of the wall of the renal pelvis in 42, and/or a focal hyper- or hypoechogenicity in 36, and/or a diffuse hyperechogenicity in 31 children. Micturating cystourethrography was performed in all children, revealing vesicoureteral reflux (VUR) in 22 (31%). Among those children with VUR, 4 had a normal DMSA scan, 2 an abnormal RUS, and 2 a normal DMSA scan and RUS. Our data suggest that B-mode RUS performed with a high-frequency transducer by a trained radiologist is nearly as sensitive as the DMSA scan in diagnosing renal involvement in children with unobstructed APN and in predicting VUR.

Acute Disease↗
PubMed1999

Experience with Salmonella typhi Vi capsular polysaccharide vaccine.

Typhoid fever remains an important health threat in many parts of the world, with an estimated 16 million cases and 600,000 deaths occurring each year. The emergence of Salmonella typhi strains multiply resistant to antibiotics has complicated the treatment of this disease. Field experience of 8 years shows that a vaccine composed of purified Vi capsular polysaccharide of Salmonella typhi, given as a single intramuscular or deep subcutaneous injection, has consistent immunogenicity and efficacy. Side effects, based on reports since 1989, are infrequent and mild. Furthermore, the Vi vaccine may be administered simultaneously with other common "travel" vaccines, at two different sites of injection, without affecting immunogenicity and tolerability. This review presents an update of the development and clinical experience with the Salmonella typhi Vi polysaccharide vaccine (Typhim Vi; Pasteur Mérieux Connaught, France).

Antibodies, Bacterial↗
PubMed1999

Endoscopic Nd:YAG laser therapy for villous adenomas of the right colon.

BACKGROUND: Endoscopic laser therapy is considered an acceptable treatment of benign colorectal adenomas. The aim of our study was to evaluate the efficacy of Nd:YAG laser to ablate right-sided colonic sessile adenomas. METHODS: Between January 1990 and February 1996, 56 patients underwent laser therapy because of high operative risk or refusal of surgery. Lesions were located as follows: cecum (23), ascending, (15), and hepatic flexure (18). Six patients (10.7%) had multiple polyps in the ascending colon. Histologic examination showed a tubulovillous pattern in 20 (35.7%) and a villous pattern in 36 (64.3%). Low-grade dysplasia was detected in 44 patients (78. 5%) and high-grade dysplasia in 12 (21.4%). RESULTS: The number of laser sessions ranged between 1 and 6 (median 3) and complete ablation, histologically confirmed, was achieved in 49 cases (87.5%). Seven patients (12.5%) underwent surgery: 2 for incomplete tumor destruction, 3 because of invasive carcinoma on repeated biopsies. Two patients (3.6%) had complications (one perforation of the cecum and one hemorrhage). Follow-up ranged from 6 to 60 months and no recurrences were observed. CONCLUSION: Laser therapy is an effective method for the destruction of sessile adenomas of the right colon in selected patients.

Adenoma, Villous↗
PubMed1999

A prospective study of pancreatic disease in patients with alcoholic cirrhosis: comparative diagnostic value of ERCP and EUS and long-term significance of isolated parenchymal abnormalities.

BACKGROUND: The prevalence of pancreatic disease in patients with alcohol-related liver cirrhosis is uncertain. We assessed the prevalence of pancreatic abnormalities in patients with alcoholic cirrhosis, and we compared endoscopic ultrasonography (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) for the detection of chronic pancreatitis and other pancreatic lesions. In addition, we assessed the long-term significance of isolated pancreatic parenchymal abnormalities detected at EUS. METHODS: EUS and ERCP were performed in each patient. Subjects with minimal parenchymal changes at initial EUS underwent clinical follow-up and subsequent EUS and/or ERCP to document the occurrence, absence, or progression of these changes. RESULTS: Seventy-two patients with alcoholic cirrhosis were recruited. Chronic pancreatitis was diagnosed in 14 patients (19%) by both methods independently. Isolated parenchymal lesions were observed in 18 patients by EUS alone. After a mean follow-up of 22 months the EUS appearance was unchanged. Ten of the 18 patients underwent follow-up ERCP and this was normal in all cases. CONCLUSIONS: This study demonstrated that (1) 19% of patients with alcoholic cirrhosis have chronic pancreatitis, (2) an additional 25% have isolated pancreatic parenchymal changes at EUS, and (3) these parenchymal abnormalities do not progress during follow-up.

Aged↗
PubMed1999

[Association of severe bronchial disease (bronchial casts, bronchiectasis) and partial abnormal pulmonary venous drainage in 2 children with Turner's syndrome].

UNLABELLED: The prevalence of cardiovascular malformation is high in Turner's syndrome. We report two cases of partial anomalous pulmonary venous drainage associated with a severe bronchial disease. CASE REPORTS: Case 1: a 5-year-old girl with monosomy X presented with acute respiratory failure. The chest X-ray showed an atelectasis of the left lower lobe. The patient improved following bronchoscopic removal of a bronchial cast. During hospitalization, an anomalous pulmonary venous drainage of the right lung was discovered. In spite of complete surgical repair of the cardiac malformation, several episodes of respiratory failure occurred several years after the operation. Case 2: a 9-year-old girl with monosomy X and coarctation of the aorta underwent pre-operative cardiac catheterization. She had a history of bronchiectasis, leading to a lobectomy. Her respiratory condition improved following surgery. A partial anomalous pulmonary venous return was discovered during the cardiac angiography. The coarctation was repaired surgically. The correction of the left-to-right shunt was not necessary. CONCLUSION: The partial anomalous pulmonary venous return is frequently reported in Turner's syndrome. The possible respiratory disease associated with this cardiac malformation is usually described as a consequence of the increase in pulmonary blood flow. Our two cases did not match this hypothesis.

Angiography↗
PubMed1999

[Hematuria revealing primary hyperparathyroidism in a child].

BACKGROUND: Hematuria rarely reveals primary hyperparathyroidism in the child. CASE REPORT: A 10-year-old boy presented with gross hematuria and urolithiasis. Biological findings showed hypercalcemia and hypercalciuria. Initially, parathormone plasma levels remained within normal range, but raised after a few months and at that time, ultrasound scan examination showed a parathyroid adenoma. Nevertheless, two surgical explorations were necessary to cure hypercalcemia and hyperparathyroidism. Histological aspects of parathyroid adenoma were not found on pathological examination. CONCLUSION: Symptomatic hypercalciuria may be the first symptom revealing primary hyperparathyroidism in children. Surgical treatment remains difficult in such a case.

Calcium↗
PubMed1999

Mechanical characterization in shear of human femoral cancellous bone: torsion and shear tests.

In order to investigate and compare the mechanical behaviour of human cancellous bone during different shear loading modes, two tests were performed to characterise human femoral cancellous bone in shear: a torsion test until failure and a shear test using a sharpened stainless steel tube. Paired cylindrical samples were core drilled from 12 human femoral heads, symmetrically with respect to the coronal plane and along the primary trabecular direction. The distal part of the sample was assigned to a torsion test and the shear test was performed on the proximal part along two perpendicular anatomical directions. Apparent densities and tissue densities were measured on both torsion and shear specimens. The mean torsion properties were shear modulus G, 289 (183) MPa, ultimate stress tau(torsion), 6.1 (2.7) MPa, ultimate strain gamma(ultimate), 4.6 (1.3)%, yield stress tau(yield), 4.3 (1.9) MPa and yield strain gamma(yield), 1.8 (0.3)%. Strong correlation was obtained between G and tau(torsion) (r'=0.853, p<0.001). These torsion properties were correlated with apparent density of torsion specimens showing, respectively: r'=0.713, p=0.005 and r'=0.671, p=0. 008. Properties from the shear test were invariable with regard to the two tested directions then isotropic ultimate shear stress and isotropic elementary shear stress, which represent the mean values of the two tested directions were, respectively, tau(shear), 10.0 (4. 5) MPa and tau(elem), 18.8 (6.1) MPa. Both shear stresses were correlated with apparent density of shear specimens: tau(shear), r'=0.564, p=0.045 and tau(elem), r'=0.636, p=0.024. Apparent densities for shear specimens were superior than for torsion specimens (p=0.06) and the comparison was the opposite for tissue densities (p=0.028), showing strong density gradients of cancellous bone in the femoral head. These torsion and shear tests which permit the evaluation of cancellous bone behavior under two different types of shear loading, may be performed on different human sites and the measured shear properties may be compared to structural properties of cancellous bone.

Aged↗
PubMed1999

Prevalence of cholelithiasis: results of an epidemiologic investigation in Vidauban, southeast France. General Practitioner's Group of Vidauban.

Cholelithiasis leads to 80,000 cholecystectomies being performed every year in France, but its prevalence is still unknown. The aim of this study was to assess the prevalence and risk factors of cholelithiasis in a random population of 1027 women and 727 men over the age of 30 in a small town in the southeast of France. Detailed clinical history, dietary investigation, and gallbladder ultrasound were collected for each subject and assessed by univariate analysis. A regression model was used in the multivariate analysis to detect the relative risk of cholelithiasis. Cholelithiasis was found in 130 individuals (global prevalence 13.9%). The relative risk for lithiasis was higher in women compared to men (1.89). Age (P<0.0001) and body mass index (BMI) >25 (P = 0.013) were also significant risk factors. Neither pregnancy nor oral contraceptive use proved to be risk factors. Typical biliary colic pain was the only symptom significantly associated with cholelithiasis (P<0.0001). These results show that the prevalence of gallstones in France is similar to that in Denmark and Italy.

Adult↗
PubMed1999

Stepwise building of a 115-kDa macromolecular edifice monitored by electrospray mass spectrometry. The case of acetohydroxy acid isomeroreductase.

The macromolecular complexes formed by the enzyme acetohydroxy acid isomeroreductase with NADPH, magnesium ions and the competitive inhibitor N-hydroxy-N-isopropyloxamate (IpOHA) were analysed by electrospray mass spectrometry. Each ligand was added successively to a protein solution, allowing the stoichiometry of the whole macromolecular edifice (115 583 Da) to be unambiguously determined. The combination of an electrospray ion source with the high mass range magnetic instrument used in the present studies proved to be a very powerful tool for characterizing, in a specific manner, the quaternary structures of proteins by single mass measurements.

Alcohol Oxidoreductases↗
PubMed1999

The role of endoscopic retrograde cholangiopancreatography in the management of hepatic hydatid disease.

BACKGROUND AND STUDY AIMS: Hydatid disease of the liver, and its complications, causes serious morbidity and mortality. We evaluated the role of endoscopic retrograde cholangiopancreatography (ERCP) in the management of hepatic hydatid disease. PATIENTS AND METHODS: This retrospective analysis includes 28 patients with hepatic hydatid disease who underwent ERCP. ERCP was performed preoperatively in 11 patients, for acute cholangitis (n =7), acute pancreatitis (n = 1) and right upper quadrant pain (n = 3), and in eight asymptomatic cases to search for fistulae between the cyst and the biliary tree. In a further nine patients ERCP was performed for early (< 30 days; n = 7) and late (n = 2) postoperative biliopancreatic problems. RESULTS: In all seven patients with cholangitis preoperative ERCP with EST and ductal clearance of daughter cysts and debris led to substantial clinical improvement, including four acutely ill elderly patients who stabilized and were later able to undergo surgery. EST in two of the three patients with pain who had papillary stenosis led to resolution of the abdominal pain. Six of the seven postoperative fistulae could be successfully treated endoscopically using EST. CONCLUSIONS: This study demonstrates the usefulness of ERCP in symptomatic patients with hepatic hydatid cysts; EST enables clearance of the common bile duct and allows healing of postoperative fistulae in the majority of patients. We do not, however, recommend performing routine preoperative ERCP in asymptomatic patients with the disease.

Aged↗
PubMed1999

Effect of endoscopic sphincterotomy on bile lithogenicity in patients with gallbladder in situ.

BACKGROUND AND STUDY AIMS: Endoscopic sphincterotomy results in a continuous flow of bile into the duodenum and consequently leads to an increase in the frequency of enterohepatic bile acid cycling. Because bile acids are the driving force of biliary secretion, sphincterotomy may affect bile genesis. The present study was undertaken to determine the influence of endoscopic sphincterotomy on bile composition. PATIENTS AND METHODS: The cholesterol saturation index and the bile acid pattern were determined in the gallbladder bile of lithiasis patients with (group III) or without sphincterotomy (group I), and in the hepatic bile of patients with gallbladder in situ who were checked at 3 months after the endoscopic procedure (group II). Stones from each patient were examined for chemical composition and microstructure. RESULTS: All the patients had cholesterol stones. After endoscopic sphincterotomy the molar percentages of cholesterol in the gallbladder bile of group III and in the hepatic bile of group II were significantly lower (-31% and -46% respectively) than in group I. Similarly, the cholesterol saturation index in the hepatic bile (0.79) and the gallbladder bile (0.86) from patients who had undergone sphincterotomy indicated undersaturation whereas bile from group I was oversaturated (1.25). On the other hand, endoscopic sphincterotomy did not modify the hydrophobicity index of the bile acid pool, even though deoxycholate content increased. CONCLUSIONS: Endoscopic sphincterotomy causes a marked decrease in the lithogenicity of bile and thus may prevent the risk of recurrence of cholesterol lithiasis.

Absorptiometry, Photon↗
PubMed1999

Survival rates of malignant gliomas in Burgundy from 1990 to 1995.

The aim of this study was to provide current data on case-fatality rates of malignant gliomas in the area of Burgundy (1,300,000 inhabitants). The ascertainment was specific according to imaging and histologic criteria, and was exhaustive because of the existence of a single University Hospital allowing both imaging and histologic diagnosis from stereotaxic cerebral biopsy. During six full years we collected 161 cases of malignant gliomas grades II to IV, 93 men (57.76%) and 68 women (42.23%). The mean age was 61 years. In all the age groups, there were a male predominance. Headache, epilepsy and motor deficit were the most frequent symptoms at onset. In most cases, the gliomas were localized within the frontal area. The post-surgical Karnofsky score was up to 70 in 40% of the cases. There were 89 glioblastomas with grade IV, 37 anaplastic astrocytomas, 13 gliomatous tumors with grade II and IV and six anaplastic oligodendrogliomas. This grading explains the very low survival rates, with a negative effect induced by age. Among the most relevant contributions of this study to the clinical features of malignant gliomas is an analysis of case-fatality rates, evaluation of health care services and therapeutic trials.

Adolescent↗