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Biomedical subjects

R Dumas

Publications and source records attributed to R Dumas.

At least 109 records · Page 6Linked to original sources
PubMed1997

[Agenesis of the corpus callosum: modes of manifestation in adults].

Agenesis of corpus callosum is an uncommon brain malformation that is usually detected in childhood. In adult, focal epileptic seizure is the most frequent manifestation. Otherwise, asymptomatic patients can be detected by cerebral imagery with specific criteria. Neither developmental disability nor interhemispheric transfer dysfunction are observed in those patients. Minor facial abnormalities can be found. Agenesis of corpus callosum in adult is usually paucisymptomatic. The prognosis depends on cerebral associated malformations which are involved in epilepsy and cognitive disturbances.

Adolescent↗
PubMed1997

[Acute inoperable cholecystitis treated by endoscopic naso-vesicular drainage. Study of 15 patients].

OBJECTIVES: Cystic duct cannulation during endoscopic retrograde cholangiography is now possible, due to advances in endoscopic equipment and methodology. The aim of this study was to assess the role of endoscopic transpapillary cholecystostomy in inoperable patients with acute cholecystitis. METHODS: Between October 1993 and February 1996, cystic duct cannulation was performed in 15 patients with acute cholecystitis (9 men and 6 women; mean age 74.8 years. Acute calculous cholecystitis was associated with cholangitis in 4 cases, with pancreatitis in 2 cases, and with perforation of the gallbladder in 1 case. RESULTS: Cystic duct cannulation was successful in 13 patients (86.6%), and resulted in remission of cholecystitis by nasovesicular drainage associated with antibiotherapy in all cases. No morbidity and mortality due to this method was observed at one month. No recurrence was observed after a mean follow-up of 8 months (range: 6 weeks-14 months). CONCLUSION: This study suggests that endoscopic nasovesicular drainage is a good alternative treatment to percutaneous cholecystostomy in inoperable patients.

Acute Disease↗
PubMed1996

Characterization of an Arabidopsis thaliana cDNA encoding an S-adenosylmethionine-sensitive threonine synthase. Threonine synthase from higher plants.

An Arabidopsis thaliana cDNA encoding an S-adenosylmethionine-sensitive threonine synthase (EC 4.2.99.2) has been isolated by functional complementation of an Escherichia coli mutant devoid of threonine synthase activity. Threonine synthase from A. thaliana was shown to be synthesized with a transit peptide. The recombinant protein is activated by S-adenosylmethionine in the same range as the plant threonine synthase and evidence is presented for an involvement of the N-terminal part of the mature enzyme in the sensitivity to S-adenosylmethionine.

Amino Acid Sequence↗
PubMed1996

Reduced brain N-acetyl-aspartate in frontal lobes suggests neuronal loss in patients with amyotrophic lateral sclerosis.

We performed proton magnetic resonance spectroscopy (1H-MRS) in three patients with amyotrophic lateral sclerosis (ALS) to evaluate the distribution and extent of cortical neuronal damage as demonstrated by decreased N-acetyl-aspartate (NAA) levels. We examined primary motor (precentral gyrus) and parietal neocortical (superior parietal gyrus) regions. ALS was defined with lower and upper motor neuron signs. Compared with matched healthy controls, ALS patients had a significant decrease in NAA levels in the primary motor cortex (p < 0.001) compared with parietal regions and homologous regions in healthy controls. Two clinical applications can be extracted: first, the upper motor neuron signs present in the ALS, come from a neuronal loss within the primary motor cortex and may explain the frontal syndrome associated with ALS. Second clinical applications of 1H-MRS could include identification of extent of upper motor neuron involvement, aiding diagnosis of syndromes presenting with an ALS-like syndrome.

Aged↗
PubMed1996

Asymmetric metabolic profile in mesial temporal lobes: localized H-1 MR spectroscopy in healthy right-handed and non-right-handed subjects.

PURPOSE: To determine a possible asymmetric metabolic profile in right- handed and non-right-handed healthy subjects by comparing proton spectra from temporal lobes. MATERIALS AND METHODS: Twenty-eight healthy adults (17 right-handers, 11 non-right-handers) underwent magnetic resonance (MR) imaging and single-voxel MR spectroscopy. N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) peak areas were measured. RESULTS: Volume of hippocampal formations was larger on the right in right-handers (right volume: 4.04 cm3 +/- 0.67 vs left volume: 3.84 cm3 +/- 0.62; P = .00004) and in non-right-handers (right volume: 4.22 cm3 +/- 0.78 vs left volume: 4.05 cm3 +/- 0.80; P = .004). NAA/Cho was significantly higher in the left temporal lobe of right-handers (right lobe: 1.53 +/- 0.18 vs left lobe: 1.89 +/- 0.18; P=.00004) as was NAA/Cr (right lobe: 1.79 +/- 0.36 vs left lobe: 2.45 +/- 0.45; P=.0001). No statistically significant difference was noted for these ratios in non-right-handers: NAA/Cho (right lobe: 1.49 +/- 0.18 vs left lobe: 1.61 +/- 0.35) and NAA/Cr (right lobe: 1.93 +/- 0.45 vs left lobe: 2.40 +/- 0.70). CONCLUSION: A clear metabolic asymmetry observed in right-handers is less clear-cut in non-right-handers. Both tendencies should be considered when assessing the brain metabolism of patients with uni- or bilateral disorders, such as temporal lobe epilepsy.

Adult↗
PubMed1996

Molecular diagnosis of Charcot-Marie-Tooth 1A disease and hereditary neuropathy with liability to pressure palsies by quantifying CMT1A-REP sequences: consequences of recombinations at variant sites on chromosomes 17p11.2-12.

The most frequent form of Charcot-Marie-Tooth disease (CMT1A; OMIM118.220) is the result of a duplication on chromosome 17 in pll.2-p12. This region contains PMP22, a gene expressed in peripheral myelin. The mutation results from an unequal crossing-over involving repeated sequences, CMT1A-REP, located on both sides of the duplicated region. The reciprocal product of this recombination is a deletion of the same region, which is associated with hereditary neuropathy with liability to pressure palsies (HNPP; OMIM162.500). Proximal and distal CMT1A-REP sequences can be distinguished by the presence of a variant EcoRI site. We quantified the number of these repeat sequences in 36 CMT1A and 40 HNPP patients. CMT1A-REP sequences are involved in almost all of the mutations. The majority of recombination breakpoints occur distally from the variant EcoRI site. However, a few have a breakpoint proximal to this site, which creates the risk of misinterpretation with respect to a duplicated/deleted status.

Charcot-Marie-Tooth Disease↗
PubMed1996

[Cardiac adaptation to muscular exercise in children after complete repair of tetralogy of Fallot].

The aim of this study was to assess cardiac adaptation to muscular exercise in children operated for tetralogy of Fallot. Eight children with a history of tetralogy of Fallot were studied and compared with ten control children. The basal evaluation consisted of an electrocardiogram, spirometry in all cases. Chest X-ray and echocardiography in all operated children. A muscular exercise stress test with incremental load on a bicycle ergometer was carried out with measurement of the cardiac output by CO2 rebreathing (experimental method). Under resting conditions, the two groups were comparable with respect to anthropometrical parameters and respiratory function. The cardiovascular data confirmed the good postoperative results of the children with a history of tetralogy of Fallot; cardiothoracic index of 0.49 to 0.55; sinus rhythm on the electrocardiogram; right ventricular pressures within normal limits; residual instantaneous right ventricular-pulmonary artery pressure gradient less than 25 mmH. On exercise, there was no significant difference with respect to VO2max, maximal heart rate, maximal cardiac output and maximal ventilation. The relationship between cardiac output and oxygen consumption was linear in two groups: y = 8.17x + 1.95 in the control group, y = 8.57x + 2.82 in the operated children. The change in cardiac output on exercise was comparable in the two groups. These observations seemed to be related to the good postoperative haemodynamic result: absence of pulmonary sequellae and right ventricular dysfunction. Despite the normality of the results obtained in this series, exercise stress testing with analysis of cardiac and respiratory adaptation would seem to be necessary in the follow-up of children operated for tetralogy of Fallot to exclude a ventilatory or circulatory limitation.

Adaptation, Physiological↗