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Biomedical subjects

R Dumas

Publications and source records attributed to R Dumas.

At least 163 records · Page 9Linked to original sources
PubMed1993

PCR analysis and sequencing of the SRY sex determining gene in four patients with bilateral congenital anorchia.

OBJECTIVE: We explored the possibility of a genetic anomaly in the sex determining region of the Y chromosome, SRY gene, known to be equated to the testis determining region. PATIENTS: Four patients with bilateral congenital anorchia, absence of testicular tissue, elevated FSH and a lack of testosterone response to human chorionic gonadotrophin stimulation tests were studied. MEASUREMENTS: Amplification by polymerase chain reaction of the SRY gene and direct double stranded DNA sequencing were performed with the same primers. RESULTS: The expected 648 basepairs band of SRY was detected in the four DNA samples from patients with bilateral congenital anorchia. Direct sequencing did not show any difference with the previous published sequence. CONCLUSIONS: These data suggest that, in the four patients, bilateral congenital anorchia is not related to an anomaly of the opening reading frame sequence of the SRY gene.

Child, Preschool↗
PubMed1993

[Lissencephaly. Clinical, electroencephalographic and radiological aspects].

We report 2 cases of lissencephaly and review the cardinal symptoms: microcephalia, mental retardation, pyramidal syndrome and generalized epilepsy. CT-Scan and MRI show the anatomical abnormalities of this malformation: microcephalia, smooth cortex reducing the surface of white matter and lack of sulci and gyri. The fact that the myelin is normal on MRI suggests that this major disorder of neuronal migration does not come from radial glial fibers.

Cerebral Cortex↗
PubMed1993

[Transient neurologic deficit preceding intracerebral hemorrhage. Physiopathological hypotheses].

Seventeen out of 238 cases (7%) of intracerebral hemorrhage were preceded by transient neurological deficit. In two cases, intracerebral hemorrhage and transient neurological deficit were thought to be due to amyloid angiopathy, this diagnosis was confirmed at autopsy in one case. In one case, intracerebral hemorrhage and transient neurological deficit were due to a cavernoma. In the other 14 cases, hypertension was the major risk factor. In 3 of them, CT-scans made after the transient neurological deficit but before the intracerebral hemorrhage showed deep small hypodensities suggestive of lacunas. The mechanisms of transient neurological deficit preceding intracerebral hemorrhage are reviewed.

Aged↗
PubMed1993

[Agenesis of the corpus callosum and epilepsy. 26 cases].

Agenesis of the corpus callosum is a cerebral malformation diagnosed by CT scan. Beside mental retardation, the most frequent clinical manifestation is epilepsy. In a personal study of 26 cases, the authors analysed the clinical features of epileptic seizures observed with this malformation. They put the stress on the paradoxical presence of generalized seizures.

Abnormalities, Multiple↗
PubMed1993

[Functional hemispheric arousal and egocentric reference. An experimental study in 20 normal subjects].

The aim of this study was to evaluate the influence of each hemispheric functional arousal (right or left) on the designation of a subjective egocentric reference. The subjective designation of a egocentric reference was measured and compared in 20 right-handers healthy volunteers in cognitive tasks concerning either the right or the left hemisphere. The location of the egocentric reference was different during right or left hemispheric arousal. The hemispheric arousal induce a displacement of the egocentric reference to the contralateral space. These results are compared with clinical and neurophysiological studies and suggest new explorations to the mechanisms of heminegligence.

Adult↗
PubMed1993

[Mortality of cerebral infarction with auricular fibrillation. Results of a population study].

To evaluate the relationship between atrial fibrillation (AF) and mortality of the cerebral infarction, we have studied in a population survey, 540 cerebral infarctions, whose 162 were with AF (30%) and 378 without AF (70%). The group with AF differs significantly from that without AF, by the higher frequency of women (62% versus 35%), older subjects (75.4 +/- 10.2 years old versus 69.1 +/- 9.7 years old), a severe loss of consciousness, a more frequent subcortical infarction on CT-Scan. During a period of 24 months, 139 patients died, 64 among the 162 patients with AF (40%), 75 among the 378 patients without AF (20%). Rates of death are different in the 2 groups with, in the group with AF, at 1, 6, 18 and 24 months a rate of 20, 24, 37 and 40 percent. To the opposite, in the group without AF, the rates are 8, 12, 16 and 20 percent. The authors try to research the factors that may explain the mortality linked to AF, and they insist on the necessity to look for AF on admission for a stroke, to identify a subgroup of stroke patients with a high risk of death.

Aged↗
PubMed1992

Isolation and kinetic properties of acetohydroxy acid isomeroreductase from spinach (Spinacia oleracea) chloroplasts overexpressed in Escherichia coli.

Acetohydroxy acid isomeroreductase catalyses a two-step reaction, an alkyl migration and a NADPH-dependent reduction, in the assembly of the carbon skeletons of branched-chain amino acids. Detailed investigations of acetohydroxy acid isomeroreductase aimed at elucidating the biosynthetic pathway of branched-chain amino acids and at designing new inhibitors of the enzyme having herbicidal potency have so far been conducted with the enzymes isolated from bacteria. To gain more information on a plant system, the gene encoding the mature acetohydroxy acid isomeroreductase from spinach (Spinacia oleracea) leaf chloroplasts has been used to transform Escherichia coli cells and to overexpress the enzyme. A rapid protocol is described that allows the preparation of large quantities of pure spinach chloroplast acetohydroxy acid isomeroreductase. Kinetic and structural properties of the plant enzyme expressed in Escherichia coli are compared with those reported in our previous studies on the native enzymes purified from spinach chloroplasts and with those reported for the corresponding enzymes isolated from Escherichia coli and Salmonella typhimurium. Both the plant and the bacterial enzymes obey an ordered mechanism in which NADPH binds first, followed by substrate (either 2-acetolactate or 2-aceto-2-hydroxybutyrate). Inhibition studies employing an inactive substrate analogue, 2-hydroxy-2-methyl-3-oxopentanoate, showed, however, that the binding of 2-hydroxy-2-methyl-3-oxopentanoate and NADPH occurs randomly, suggestive of some flexibility of the plant enzyme active site. The observed preference of the enzyme for 2-aceto-2-hydroxybutyrate over 2-acetolactate is discussed with regard to the contribution of acetohydroxy acid isomeroreductase activity in the partitioning between isoleucine and valine biosyntheses. Moreover, the kinetic properties of the chloroplast enzyme support the notion that biosynthesis of branched-chain amino acids in plants is controlled by light. As judged by analytical-ultracentrifugation and gel-filtration analyses the overexpressed plant enzyme is a dimer of identical subunits.

2-Acetolactate Mutase↗
PubMed1992

Sphenoidal electrode insertion under local analgesia in children.

The indications for method and the results of sphenoidal electrode insertion under local analgesia are evaluated in children. This technique makes it possible to study the hippocampal area, which cannot be studied by other extracranial electrodes. It also localizes in a temporal lobe some complex seizures without electrical events on surface recordings, complex seizures with bilateral temporal spikes or a frontotemporal focus of spikes, as well as those with a temporal focus with bilateral synchronous spikes in standard EEG. Therefore, sphenoidal electrodes inserted without heavy general analgesia enable temporal seizures to be identified and localized, leading to more specific neuroradiological and neurophysiological explorations and helping in this way to select possible patients for epileptic surgery.

Adolescent↗
PubMed1992

Effect of somatostatin analog octreotide on human sphincter of Oddi.

The effect of the long-acting somatostatin analog octreotide on the sphincter of Oddi was investigated in seven subjects referred for endoscopic sphincter of Oddi manometry. Six patients had unexplained right upper quadrant pain and one had bile duct dilatation without evidence of fixed obstruction on endoscopic retrograde cholangiopancreatography. A triple-lumen low-compliance system was used to record the sphincter of Oddi basal pressure, phasic contraction frequency, amplitude, duration, and direction of wave propagation before and after intravenous administration of octreotide in a dose of 50 micrograms. After a mean latency period of 1 min, significant changes included increased basal pressure in all seven patients, increased frequency of wave contractions in six patients, and decreased wave amplitude in six patients. The median duration of wave contraction and wave propagation sequence were not significantly influenced. Thus, octreotide has a significant stimulatory affect on the sphincter of Oddi activity, which may impair biliary and pancreatic flow.

Adult↗
PubMed1992

Vascular manifestations in homocystinuria.

Homocystinuria was discovered in a 21-year-old woman when she presented with lower limb ischemia and pulmonary embolism. This patient had a partial deficit in cystathionine-synthetase and took strongly dosed oral contraceptive medication. This report underscores: (1) the value of searching for this type of pathology even in the adult; (2) the possibility of disclosure by another condition, and particularly, drug-induced; (3) the importance of searching for other involved members of the same family; and (4) the possibility of treatment in vitamin sensitive patients.

Adult↗
PubMed1992

[Investigation via electroencephalogram with sphenoidal electrodes of a case of reading epilepsy: role of the temporal lobe in the emotional evocation of seizures].

Reading epilepsy in a 20-year-old male. Electroencephalographic study with sphenoidal electrodes localized the onset of critical spikes in the temporal areas (especially the left). The frequency and diffusion of critical spikes were increased when material read had an emotional content. This case report supports the "communication" hypothesis as opposed to hypotheses that emphasize proprioceptive and other "lower order" stimuli in evoking seizures while reading. The authors discuss the role of the temporal lobe in reading: lexical function, treatment of visual information and emotional integration of stimuli.

Adult↗