Early migration of a covered self-expanding metal stent corrected by implantation of a second stent.
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Adenocarcinoma↗
Biomedical subjects
R Dumas
Publications and source records attributed to R Dumas.
[Acute cholecystitis with gallbladder perforation treated by transpapillary endoscopic drainage].
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Acute Disease↗
Evidence for two catalytically different magnesium-binding sites in acetohydroxy acid isomeroreductase by site-directed mutagenesis.
Alignment of procaryotic and plant acetohydroxy acid isomeroreductase (EC 1.1.1.86) reveals five conserved regions designated domains I, II, III, IV, and V. Domain I has been previously proposed to correspond to the NADPH-binding site [Dumas et al. (1991) Biochem. J. 277, 469-475] and domain III to a putative magnesium-binding site [Sista & Bowman (1992) Gene 120, 115-118]. The binding and the function of this cation are of particular importance. First, Mg2+ is essential for the two-step reaction catalyzed by this enzyme: an isomerization followed by an NADPH-dependent reduction. Second, the plant acetohydroxy acid isomeroreductase exhibits Kd and Km values for Mg2+ of 5 microM and 6 microM, respectively. Such values correspond to the strongest affinity known between an enzyme and the metal ion. To determine if domain III of acetohydroxy acid isomeroreductase is effectively involved in magnesium binding, and with the goal to assign a function to the other conserved domains, site-directed mutagenesis was performed on each charged or polar conserved amino acids of domains II-V of the spinach acetohydroxy acid isomeroreductase. The results demonstrate that mutation of each of these amino acids leads to a partial or complete inactivation of enzyme activity. Steady-state kinetic analysis and equilibrium binding experiments show that both domains III and IV are directly involved in the binding of magnesium. Also, they suggest that magnesium bound to domain III plays a role in the reductive half-reaction, whereas, magnesium bound to domain IV is involved in the isomerization half-reaction.
Alcohol Oxidoreductases↗
Levorotatory form of 5-hydroxytryptophan in Friedreich's ataxia. Results of a double-blind drug-placebo cooperative study.
OBJECTIVE: To study the effect of the levorotatory form of 5-hydroxytryptophan on the cerebellar symptoms of Friedreich's ataxia. DESIGN: Cooperative double-blind study of the levorotatory form of 5-hydroxytryptophan vs placebo. SETTING: Twelve centers in research hospitals. PATIENTS: Twenty-six patients were included; 19 completed the study (mean +/- SD age of patients, 25.9 +/- 8.1 years). Of these 19 patients, eight were treated with placebo and 11 were treated with the drug. MAIN OUTCOME MEASURES: A semiquantitative scale for kinetic and static ("postural") cerebellar functions and quantitative measurements of time in standard tests that evaluated stance, speech, writing, and drawing. RESULTS: In the active treatment group, a significant decrease of the kinetic score was observed (P = .03), indicating an improvement in coordination. CONCLUSIONS: These results demonstrated that the levorotatory form of 5-hydroxytryptophan is able to modify significantly the cerebellar symptoms in patients with Friedreich's ataxia. However, the effect is only partial and not clinically major.
5-Hydroxytryptophan↗
Late thalamic atrophy in infarction of the middle cerebral artery territory in neonates. A prospective clinical and radiological study in four children.
We report four cases of progressive thalamic atrophy following ipsilateral cerebral infarction in the territory of the middle cerebral artery in neonates, with prospective radiological and clinical follow-up. This type of atrophy appears within 6 months after the onset of cerebral infarction. In the short term, this atrophy has no action on sensory and memory function and/or on sensory evoked potentials. This atrophy is not the result of secondary ischemic neuronal damage. Judging from several other experimental studies, thalamic atrophy may primarily result from retrograde degeneration. It would be interesting to observe the consequences of this atrophy on sensory and memory function over a long period.
Cerebral Arteries↗
Cerebrovascular disease in children under 16 years of age in the city of Dijon, France: a study of incidence and clinical features from 1985 to 1993.
Our motivation for undertaking the present survey was to determine the incidence, the distribution, and the clinical features of ischemic and hemorrhagic strokes in children under 16 years old, in a well-defined population-based study. The survey was carried out on the population of the City of Dijon (150,000 inhibitants) from January 1, 1985 to December 31, 1993, collecting prospectively both in adulthood and in childhood (23,877 resident children). Diagnosis of stroke was established on the basis of clinical features and the mechanism was identified by CT scan from 1985 to 1987, and by CT scan and magnetic resonance imaging from 1987 to 1993. When a hemorrhagic stroke was identified, a cerebral arteriogram and an investigation of the coagulation factors were performed. When an ischemic stroke was identified, the following were performed: an ultrasound examination of the cervical arteries, a cerebral arteriogram, a lumbar puncture, an investigation of the coagulation factors and lipid status, a measurement of homocysteine in the plasma and the urine, an electrocardiogram (EKG), a Holter procedure, and a cardiac echography. During the 9 full calendar years of this study we observed 28 stroke patients from a population of 23,877 resident children. There were 17 cases of ischemic stroke, representing some 61% percent of the total, as well as 11 cases of hemorrhagic stroke, 39% percent of the total. The average annual incidence rate was 13.02/100,000 for all strokes, 7.91/100,000 for ischemic strokes, and 5.11/100,000 for hemorrhagic strokes.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
[Hereditary nephrogenic diabetes insipidus].
Congenital nephrogenic diabetes insipidus (NDI) is a rare inherited disorder characterized by the inability of the kidney to concentrate urine in response to vasopressin (AVP). Following the recent characterization of the cDNA and genomics sequences encoding the human V2 receptor to AVP (AVPR2), X-linked NDI has been found to be due to mutations in the AVPR2 gene that maps to the chromosome Xq28 region. To date more than 30 mutations, insertions or deletions have been reported in independent families, without any significant differences in the phenotypic expression of the disease. The AVPR2 is a member of the superfamily of 7 transmembrane domain, G protein-coupled receptor, linked to cyclic AMP second messenger system. Other types of inheritance have been described in NDI, and recently, a mutation of the aquaporin-2 gene, encoding a water channel of the renal collecting duct, has been reported in an autosomal recessive form of NDI.
Diabetes Insipidus, Nephrogenic↗
Role of associated cortical lesions in motor partial seizures and lenticulostriate infarcts.
In a population-based study, we evaluated seizures occurring in the first 15 days after strokes among 1,640 consecutive patients who had ischemic (814 infarcts with atheroma and 126 with cardiogenic embolism, 273 lacunar infarcts, 259 transient ischemic attacks) or hemorrhagic stroke (129 supratentorial hematomas and 24 subarachnoïd hemorrhage) on computed tomography (CT) scan. Ninety patients had an epileptic seizure in the first 15 days after stroke onset. Thirteen of the 90 had a lenticulostriate infarct, diagnosed on CT scan, without an apparent ipsilateral cortical ischemic lesion. No lenticulostriate hematoma was observed with seizures. To determine the possible existence of an ipsilateral cortical lesion, magnetic resonance imaging (MRI) with gadolinium perfusion, and HMPAO single photon emission CT (SPECT) were performed in the 13 patients with seizures. MRI showed an associated ipsilateral posterofrontal or anterotemporal cortical ischemic lesion in 11 cases, and SPECT showed decreased blood flow in the ipsilateral frontal area in all cases (superficial sylvian territory). Overall, 56 patients had a lenticulostriate infarct and clinical, CT, and MRI data from the 13 with seizures was compared with those of the 43 without seizures. Two criteria differentiated the two groups: the size of the lenticulostriate infarct was larger (8.3 vs. 3.9 cm3) and ipsilateral cortical ischemic lesions were more frequent in the group with seizures (84 vs. 9%).
Aged↗
Clinical and topographical range of callosal infarction: a clinical and radiological correlation study.
A prospective clinical and radiological correlation study was performed to determine the frequency, and the clinical and radiological features of callosal infarction. From 1 January 1993 to the end of December 1993 282 cases of cerebral infarction seen in the Neurology service of the University Hospital of Dijon were studied prospectively. Eight cases with callosal ischaemic lesions were identified by CT and MRI. A callosal disconnection syndrome occurred in only five of eight patients, related to a single, large infarct or several infarctions in the anterior part of the corpus callosum. Clinical features were characterised by left ideomotor apraxia, construction apraxia, and left agraphia in all five cases. Alien hand was noted in only two cases. There were gait disorders in three cases with MRI features of multiple lacunes in a large part of the corpus callosum, and also the subcortical areas of both hemispheres. It is emphasised that callosal infarctions are not rare and that they contribute to the clinical features of strokes. As well as the classic incomplete callosal disconnection syndrome, these callosal ischaemic lesions may induce non-specific gait disorders.
Aged↗
Risk factors for primary cerebral hemorrhage: a population-based study--the Stroke Registry of Dijon.
Risk factors for primary cerebral hemorrhage remain uncertain. The population-based Stroke Registry of Dijon provides data on the risk factors. Among residents of Dijon (France), 130 cases of primary cerebral hemorrhage hospitalized from 1985 to 1992 were matched with 130 controls by age and sex. The following data were collected: history of hypertension, alcohol consumption, tobacco consumption, history of coagulation disorder, diabetes mellitus, dyslipidemia, and infectious disease in the 7 days before admission. The following parameters were measured on admission: blood pressure, blood glucose, cholesterol, triglycerides, hematocrit, fibrinogen, prothrombin levels, platelet counts, prothrombin time, bilirubin, transaminases, gamma-glutamyltransferase, and alkaline phosphatase. Electrocardiogram and Doppler ultrasound examination of cervical arteries were performed. Statistical analysis was performed by means of relative risk ratio for paired samples when dealing with proportions, and Student's t test for quantitative variables. A stepwise discriminant analysis was carried out to establish the relative weight of the different risk factors and their discriminant values. Among the qualitative data, the significant factors were history of hypertension, alcohol consumption, cardiac arrhythmia, atherosclerosis of carotid arteries and a previous infectious disease in the 7 days before admission. Among the quantitative data, the significant factors were early hypertension, high blood glucose levels, high hematocrit, and low cholesterol levels, in the acute stage of the stroke. After multifactorial analysis, only two factors were significant: hypertension and low cholesterol levels. Our population-based case-control study showed that hypertension and low cholesterol levels are the two discriminant risk factors for both lobar and basal ganglia primary cerebral hemorrhage. Therefore, treatment of hypercholesterolemia may increase risk of cerebral hemorrhage.
Adult↗
[Value of gadolinium magnetic resonance imaging of the lumbosacral roots in acute polyradiculoneuritis].
Four patients with acute inflammatory polyradiculoneuropathy were evaluated with MRI. In 3 of 4 cases, gadolinium enhancement was observed in the nerve roots of cauda equina, on frontal and horizontal slices. This enhancement was correlated with the severity of the clinical picture and the cerebrospinal-fluid inflammatory protein concentration and supports the inflammatory nature of this forms of acute polyradiculoneuropathy.
Acute Disease↗
Use of somatostatin and its long-acting analogue, octreotide, in the treatment of pancreatic diseases.
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Hormone Antagonists↗
[Cortico-basal degeneration: a new entity].
Cortico-basal degeneration is a progressive disease comprisong characteristic features concerning both cortical and basal ganglionic dysfunction. Manifestations include akineto-rigid syndrome and apraxia strictly limited at disease onset to one hemibody, especially the left. Myoclonus, chorea a alien limb syndrome can begin within the clinicalcome. Functional exploration of the brain shows an asymmetric hypometabolism affecting both cortical and basal structures. Neuropathologic studies show pathological features including neuronal loss, gliosis and neuronal achromasia affecting the cortex (frontal and parietal), basal ganglia and locus niger. Further evaluation of this disease is needed to understand its links with the other neurological degenerative diseases especially progressive aphasia and Pick's disease.
Atrophy↗
Crystallization and preliminary crystallographic data for acetohydroxy acid isomeroreductase from Spinacia oleracea.
Acetohydroxy acid isomeroreductase (EC 1.1.1.86) is one of the enzymes involved in branched-chain amino acid biosynthesis. The enzyme from spinach (Spinacia oleracea) leaves has been crystallized using the hanging drop vapour diffusion method. The free enzyme crystallized from polymethylene glycol solutions, but these crystals were unsuitable for X-ray diffraction analysis. In the presence of NADPH, Mg(2+) and a reaction intermediate analogue (2-dimethylphosphinoyl-2-hydroxy acetic acid (Hoe 704) or N-hydroxy-N-isopropyloxamate (IpOHA)), much better crystals were obtained. Crystals grown from ammonium sulphate belong to space group P2(1) with cell dimensions a + 193.78(7) A, b = 63.69(2) A, c = 112.84(1) A and beta = 121.22(1) degrees. The molecular mass of the protein, the volume of the unit cell, and crystal density measurements indicated that the asymmetric unit contains two dimers. X-ray diffraction patterns showed measurable reflections to beyond 2.5 A.
Alcohol Oxidoreductases↗
Interactions of plant acetohydroxy acid isomeroreductase with reaction intermediate analogues: correlation of the slow, competitive, inhibition kinetics of enzyme activity and herbicidal effects.
N-Hydroxy-N-isopropyloxamate (IpOHA) is known to inhibit extremely tightly (Ki of 22 pM) the bacterial acetohydroxy acid isomeroreductase (EC 1.1.1.86) [Aulabaugh and Schloss (1990) Biochemistry 29, 2824-2830], the second enzyme of the branched-chain-amino-acid-biosynthetic pathway. Yet, although the same pathway exists in plant cells, this compound presents only very poor herbicidal action. Towards the goal of gaining a better understanding of this behaviour, we have studied the mechanism of interaction of this compound with a highly purified acetohydroxy acid isomeroreductase of plant origin, i.e. the spinach (Spinacia oleracea) chloroplast enzyme. IpOHA behaved as a nearly irreversible inhibitor of the enzyme. Encounter complex formation was very slow (association rate constant 1.9 x 10(3) M-1.s-1) and involved a single bimolecular step. Since inhibition was competitive with respect to acetohydroxy acid substrates, the time needed to achieve substantial (90%) inhibition in vitro of enzyme activity in the simultaneous presence of substrates and inhibitors was extremely long (for example of the order of hours at 1 microM IpOHA and 100 microM acetohydroxy acid substrates). Thus, under in vivo conditions, binding of the inhibitor may be so slow that it may delay considerably the time required for inhibition of the target enzyme. Simialr kinetic behaviour was observed with another reaction intermediate analogue described by Schulz, Spönemann, Köcher and Wengenmayer [(1988) FEBS Lett. 238, 375-378], 2-dimethyl-phosphinoyl-2-hydroxyacetic acid (Hoe 704), which displays a higher herbicide activity than IpOHA. The herbicidal potency of these two compounds appeared to be correlated with their rates of association with the plant acetohydroxy acid isomeroreductase, since the bimolecular rate constant for Hoe 704 (2.2 x 10(4) M-1.s-1) was higher than that for IpOHA.
Alcohol Oxidoreductases↗
[Effect of smoking in cerebral vascular accidents].
Until recently, the effect of smoking as a risk factor in cerebral vascular events had not been analyzed carefully and no causal relationship had been identified. This could appear paradoxical since it has been well established that smoking plays a role in the pathogenesis of ischaemic cardiopathies and peripheral angiopathies. Indeed, several population studies have demonstrated that smoking plays a role in meningeal haemorrhage, but in other types of cerebral vascular events, biases related to the heterogeneous character of the involved mechanisms could explain the lack of any identifiable relationship. The most recent hospital series both in Europe and in North America based on case-control studies have however demonstrated that tobacco smoking is a vascular risk factor for most types of cerebral vascular events. Increased risk has been estimated between 1.7 and 5.7. While smoking habits in Western countries have declined, these findings emphasize the importance of the tendency towards an increased rate of cigarette smoking in third-world countries. In addition, from a public health standpoint, smoking is an extremely interesting aetiological factor since it is theoretically controllable.
Arteriosclerosis↗
Decrease in cerebellar blood flow in patients with Friedreich's ataxia: A TC-HMPAO SPECT study of three cases.
Three cases of Friedreich's ataxia were submitted to diverse neuroradiological procedures in order to determine the extent of atrophic processes in the central nervous system. All patients underwent computerized-tomography scan, Magnetic Resonance Imaging, and HMPA-single Photon emission computerized tomography studies, focusing in cerebellar lobes. A slight atrophy was observed in the vermis and the cerebellar lobes with CT scan and MRI. In contrast a significant decrease in cerebellar blood flow was shown by TC-HMPAE SPECT study. The significance of these findings in understanding physiopathological mechanisms in Friedreich's ataxia is discussed.
Adult↗
Preliminary observations of metabolic characterization of bilateral temporal epileptic focus, using proton magnetic resonance spectroscopy. Three cases.
The authors report the case of 3 patients with bilateral temporal lobe epilepsy demonstrated by EEG and sphenoïdal electrodes. Two out of the 3 patients presented with childhood febrile convulsions. Their neurological and mental examination was normal. EEG showed spikes within the anterior part of the 2 temporal lobes. CT scan and MRI showed no atrophic lesion within the 2 temporal lobes. Proton magnetic resonance spectroscopy, performed within a cube of 8 cube-centimetres localized in the anterior part of the 2 temporal lobes showed a significant decrease of N-acetyl-aspartate in the 2 temporal lobes of the 3 cases, compared with controls matched with age, sex and laterality. Because N-acetyl-aspartate is a marker of the neuronal cells, the decreased level of NAA in the temporal area with spikes, may be related to a decreased number of neuronal cells, developing an abnormal tendency to seizures.
Adolescent↗