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Biomedical subjects

M Devic

Publications and source records attributed to M Devic.

At least 19 recordsLinked to original sources

Cucumber mosaic virus satellite RNA (strain Y): analysis of sequences which affect systemic necrosis on tomato.

The location of a sequence within the Y satellite RNA of cucumber mosaic virus (CMV) that confers the ability to induce necrosis on tomato plants has been analysed using chimeric satellite RNAs. These recombinant RNA molecules contained parts of the Y (necrogenic) and Ra (benign) satellite RNAs and were inoculated into tomato plants together with CMV helper virus. From the composition of the recombinant satellite RNAs that induced necrosis it was concluded that, of the nucleotides which differ between Y and Ra satellite RNAs, those affecting necrosis are on the 3' side of nucleotide 259. The composition of satellite RNAs that failed to induce necrosis implies that at least some of the necrogenic positions are on the 3' side of nucleotide 311. The symptoms induced by mutated forms of Y and Ra satellite RNAs showed that nucleotide spacing between positions 322 and 323 and sequence identity at one or more of nucleotides 318, 323 or 325 affects the necrogenic potential of Y satellite RNA. The effect of a frameshifting mutation in Y satellite RNA and the location of the necrogenic sites relative to open reading frames in other satellite RNAs suggested that necrosis is not caused by polypeptides encoded in satellite RNA.

Base Sequence

Cucumber mosaic virus satellite RNA (Y strain): analysis of sequences which affect yellow mosaic symptoms on tobacco.

Plants infected with cucumber mosaic virus (CMV) (KIN strain) produce a mild mosaic disease on tobacco whereas infections of CMV with satellite RNA (strain Y) cause a severe yellow mosaic. Analysis of recombinant and mutant forms of satellite RNA identified a site (nucleotides 185/186) in the Y satellite RNA that affects the ability to induce the yellow mosaic in combination with CMV but not with tomato aspermy virus. The location of this site with respect to other mutations in the satellite RNA indicated that polypeptides, which may be encoded by the satellite RNA, have no role in induction of yellow mosaic symptoms. The symptom induction is therefore an effect of the satellite RNA on the host plant with the intervention of the helper virus. In the course of the mutation analysis of satellite RNA we detected several secondary mutations which arose in planta. Two of these were deletions of more than 80 nucleotides. Other forms of mutant satellite RNA were non-functional even though the modifications involved nucleotides completely within the large secondary deletions. These data imply complex intramolecular interactions in the satellite RNA.

Base Sequence

Symptom production on tobacco and tomato is determined by two distinct domains of the satellite RNA of cucumber mosaic virus (strain Y).

Complementary DNAs of two different satellite RNA isolates from cucumber mosaic virus (CMV), Y from Japan and Ra from France, have been cloned in a transcription vector containing the Pr promoter. When inoculated on plants with CMV RNA (strain KIN), the transcripts of the cloned Y satellite cDNA elicit a bright yellow mosaic on tobacco and a lethal necrosis on tomato. Addition of the transcripts of the Ra satellite cDNA to an inoculum of CMV RNA resulted in symptom attenuation on both tobacco and tomato, in agreement with the characterized symptoms of the natural satellite. Recombinant molecules involving these two satellites have been constructed in order to determine which parts of the Y satellite RNA are involved in symptom induction. The determinant for symptom production on tobacco lies in the region between nucleotides 1 and 219. The domain for necrotic symptoms on tomato resides on the 3' half of the molecule beyond nucleotide 219.

Base Sequence

[HLA and narcolepsy. Apropos of 28 cases including 2 negative HLA-DR2].

Association between narcolepsy and HLA-DR2 antigen is the strongest so far described between an HLA antigen and a disease. Among 28 narcoleptic patients, we found two HLA-DR2 negative cases: a caucasoid woman also suffering from dystrophia myotonica and a negroid. All of our patients were HLA-DQW1 positive. An hypothetical narcolepsy susceptibility gene could be located in the HLA region, closer to the DQ than to the DR gene. It could be a pathologic allele of a sleep controlling gene in linkage disequilibrium with DQW1. Presence of DQW1 is a quasi-requisite for the expression of narcolepsy. It is not sufficient as it is observed in 70 p. 100 of controls.

Adolescent

[Dexamethasone suppression test in psychiatric pathology].

The dexamethasone suppression test (DST) has been used in psychiatric pathology for about 10 years. Carroll et al. consider this test to be specific of endogenous depression. According to these, and many other authors, approximately 55% of patients with endogenous depression show a positive response to the test, whereas a positive response is observed in only 4% of normal subjects or patients with psychiatric disorders other than major depressive disorders. The DST was performed in 162 psychiatric inpatients (5 with organic disease, 28 with schizophrenic disorders, 17 with major affective disorders, 5 with obsessive compulsive disorders, 103 with dysthymic disorders and 4 unclassified). Dexamethasone (1 mg) was administered orally at 11 p.m., and plasma cortisol concentration was measured the following day at 16 p.m. Response to the test was positive in 53% of patients with major affective disorders, 25% of those with schizophrenic disorders, 60% with obsessive compulsive disorders and 18% with dysthymic disorders. There was no statistical difference in the results according to age, sex ratio, family history of depression or duration of the disorders. Only two variables were close to the P less than 0.05 level of statistical significance: severity of the disorders and early morning awakening. DST sensitivity, therefore, would appear to be about 50% in major affective disorders, but this test is not specific as it may also be positive in other psychiatric disorders. A positive dexamethasone suppression test may be regarded as a sign of severity of psychiatric disorders.

Depressive Disorder

[South-Eastern France, a high risk area for multiple sclerosis?].

A questionnaire-based prevalence study was conducted in the Chalon-sur-Saône and Avignon areas, in the Rhône-Saône valley, France, to determine the frequency of multiple sclerosis. These areas are 300 km apart and lie on the 47 degrees and 44 degrees North parallels respectively. Age-adjusted prevalence rates on March 20, 1984 were 58.5 and 48.6 per 100,000 inhabitants respectively. There was no significant difference between the two areas. These preliminary data suggest that south-eastern France, as represented by Avignon, may fall within the high risk area for multiple sclerosis.

France

[Ineffectiveness of hyperbaric oxygen therapy in multiple sclerosis. A randomized placebo-controlled double-blind study].

Seventeen patients with definite and progressive multiple sclerosis entered a double-blind randomized placebo-controlled therapeutic trial of hyperbaric oxygen (HBO). Exposure in monoplace chamber was 90 minutes long each time, 5 days a week, for 4 weeks. The treatment and placebo groups received 100% oxygen at 1.5 bar constant pressure or normal air at 0.1-0.2 bar, respectively. The clinical status of the patients in both groups were compared until one year after treatment. There was no benefit of HBO versus placebo according to the Kurtzke disability status scale. A lesser proportion of patients with deterioration of bowel/bladder function 12 months after therapy was the only benefit of HBO versus placebo according to Kurtzke functional systems scales. On the whole however, HBO is useless in the management of progressive forms of multiple sclerosis.

Double-Blind Method

Plasma cells in cerebrospinal fluid and multiple sclerosis: diagnostic yield and clinicobiological correlations.

Cerebrospinal fluid (CSF) cytocentrifugation was performed for plasma cells' demonstration in parallel with white cell count (WCC) and quantitative protein assays. Over a 5-year period, 154 consecutive multiple sclerosis (MS) patients were studied and compared to 28 other inflammatory neurological disease, 85 non-inflammatory neurological disease and 29 non-neurological disease cases. CSF cytology was easy to perform, gave definitive results within 2 h and was abnormal in 80 MS patients, 26 of whom had a normal WCC. Its sensitivity in MS was 0.57, i.e. higher than for WCC (0.45) but lower than for IgG index (0.70) and IgG synthesis rate (0.71). Its specificity was 0.86, not significantly different from specificity of WCC, IgG index and IgG synthesis rate. Plasma cells demonstration in MS CSF was neither a disease activity nor a prognosis marker. It was significantly correlated with pleiocytosis and intrathecal IgG synthesis. If these morphologically defined plasma cells are actual B cells, they could represent circulating individuals of the lymphocyte clones active in MS plaques and have a pathogenetic significance.

Adult

Oligoclonal "fingerprint" of CSF IgG in multiple sclerosis patients is not modified following intrathecal administration of natural beta-interferon.

The IgG pattern in CSF was studied in 11 patients with multiple sclerosis who exhibited an oligoclonal banding upon thin-layer polyacrylamide gel isoelectric focusing followed by silver stain of unconcentrated CSF. Each patient received beta-interferon intrathecally during a 2 month period. No modification was observed over a 6 month period. In addition, the oligoclonal pattern was remarkably unique for each individual representing a typical "fingerprint" which allowed the identification of any single CSF.

Electrophoresis, Polyacrylamide Gel

[Paralysis of downward gaze and chronic global amnesia as a result of a bilateral thalamo-subthalamic lesion].

A 47 year-old male was found in coma and upon awakening 36 hours later, he showed a selective paralysis of downward gaze and convergence associated to an intellectual impairment. He was euphoric, unconcerned, poorly attentive, and had a severe amnesia for both anterograde and retrograde material. CT scan and NMR demonstrated a bilateral lacunar lesion of thalamic and subthalamic paramedian region. Over the 5 years follow-up, behavioral, personality and amnestic changes remained. On the other hand, supranuclear gaze paralysis improved as documented by EOG recordings with persisting limitations in voluntary down movements amplitude and dramatic reduction of fast components velocity.

Amnesia

[Thalamic dementia after a unilateral hemorrhagic lesion of the right pulvinar].

A 68 year-old man with a history of right thalamic hemorrhage demonstrated radiologically in the pulvinar and posterior portion of the dorsomedian nucleus developed a clinical picture of severe physical sequelae associated with major affective, behavioral and psychic disorders. Affective manifestations were a permanent anxiety-depression state contrasting with indifference to his surroundings. Behavioral changes included marked apathy, inertness and hypersomnia, together with occasional clastic agitated episodes and verbal and gestural stereotypies and soliloquies. Psychic sequelae were psychotic in nature: depersonalization crises, delusions of persecution, multisensorial hallucinations and absurd acts.

Aged

Cloning of the human glucocorticoid receptor cDNA.

We show that the human glucocorticoid receptor (GR), isolated from the breast cancer cell line MCF-7, has an apparent molecular weight identical to that of rat liver GR (94 kDa) and reacts with antibodies raised against the latter. These antibodies were used to clone cDNA sequences corresponding to the human GR from a lambda gt11 expression library constructed using MCF-7 poly(A)+ RNA. Three non-homologous cDNA clones with inserts of 125, 220 and 350 bp, which express epitopes recognised by the rat liver GR antibodies, were isolated. Rat liver GR antibodies, immunopurified using the immobilised purified beta-galactosidase fusion proteins, detect partially purified rat liver and human GRs on Western blots. In addition, these antibodies immuno-adsorb rat liver and human GRs affinity-labelled with [3H] triamcinolone acetonide. Northern blot analysis, using all three cDNA probes, reveals the presence of a major MCF-7 poly(A)+ RNA species of approximately 7 kb.

Cloning, Molecular

[Encephalitis and acute amnesic encephalopathies. Retrospective study of 16 cases (author's transl)].

A retrospective study was conducted on sixteen cases of encephalitis or acute amnesic encephalopathies, only one of which was confirmed by pathological examination, seen over the last fifteen years. The amnesic syndrome was always associated with a very marked anterograde deficiency and the absence of severe disturbances of other higher functions. Its onset was always acute, was secondary to disturbances of consciousness or associated with epilepsy, and in half of the cases presented as a severe infections disorder with high fever. The mood and behavioural disorders, and the temporal epilepsy, were evidenced clinically as a pure or predominant hippocampic lesion. The diversity of the progressive nature of the disorders, and the etiological environmental factors, enable divison into three groups : a group of six cases of postencephalitic Korsakoff's syndrome, probably of herpetic origin, and associated with a stable amnesic syndrome which remained as a sequela ; a group of 5 patients with non-herpetic but probable viral "curable amnesic encephalitis" ; another group of 5 patients with "acute amnesic encephalopathy" with various etiologies and with obvious encephalitic lesions.

Acute Disease

[Surgically treated supratentorial gliomas in the adult. Favourable action of a podophyllin derivative (VM 26) administered alone (author's transl)].

The action of VM 26 on cerebral glioblastomas was suggested by studies of phase II or protocols in which the drug was used in association. The randomised protocol presented here, involving 10 treated subjects and 11 controls, showed that VM 26 was active in terms of the duration of survival of patients undergoing surgery for a glioblastoma. The mean survival was 16.4 months as against 9.6 months in the controls (statistically significant difference at p less than 0.05). This activity would tend to characterise the drug as one of the essential factors in the chemotherapy of all malignant gliomas, in particular since it is itself free of all haematological complications, even at high doses, and causes scarcely any allergic problems.

Brain Neoplasms