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Biomedical subjects

B Devaux

Publications and source records attributed to B Devaux.

107 records · Page 6Linked to original sources

H3-receptors control histamine release in human brain.

The regulation of histamine release was studied on slices prepared from pieces of human cerebral cortex removed during neurosurgery and labeled with L-[3H]histidine. Depolarization by increased extracellular K+ concentration induced [3H]histamine release, although to a lesser extent than from rat brain slices. Exogenous histamine reduced by up to 60% the K+-evoked release, with an EC50 of 3.5 +/- 0.5 X 10(-8) M. The H3-receptor antagonists impromidine and thioperamide reversed the histamine effect in an apparently competitive manner and enhanced the K+-evoked release, indicating a participation of endogenous histamine in the release control process. The potencies of histamine and the H3-receptor antagonists were similar to those of these agents at presynaptic H3-autoreceptors controlling [3H]histamine release from rat brain slices. It is concluded that H3-receptors control histamine release in the human brain.

Cerebral Cortex↗

Genomic footprinting detects factors bound to major late and IVa2 promoters in adenovirus-infected HeLa cells.

We used DNase I footprinting assays on nuclei isolated from adenovirus-infected cells to examine the nucleoprotein configuration of a 250-base-pair segment which encompasses the adenovirus type 5 major late (ML) and IVa2 promoters. At 12 and 20 h postinfection (p.i.), fine DNase I digestion mapping of wild-type adenovirus-infected cells revealed specific sequences protected from digestion which corresponded to promoter elements required for expression of the ML gene in vivo. At 12 h p.i., a G+C-rich region which lies upstream of the IVa2 cap site and is important for maximal IVa2 activity was also found masked to nuclease activity. At 20 h p.i., however, this element became more sensitive to nuclease attack, while the ML promoter elements stayed protected. No major changes in DNA-protein interactions were detected in the region spanning the ML and IVa2 cap sites upon promoter activation, suggesting that the binding properties of the cognate factors for this region are not modified during the process.

Adenoviruses, Human↗

[Stereotaxic approach in extensive lesions of the septum-fornix-callosal region. Apropos of 14 cases].

Stereotactic approach of anterior midline lesions which involve the septum-fornix-callosal region is a logical alternative to open surgery as a first choice. It contributes to know anatomical relations--particularly vascular and ventricular--of the lesion; it provides an accurate neuro-pathological diagnosis, with grading and spatial configuration of the lesion, and therapy in some cases. In other cases, it is a guide for appropriate therapeutic choice.

Adolescent↗

[Stereotaxic ventriculocisternostomy in the treatment of triventricular obstructive hydrocephalus. Apropos of 23 cases].

UNLABELLED: During the period January 1975-October 1987, we performed stereotactic ventriculocisternostomy (V.C.S.) on 23 patients (13 M., 10 F.; age: 11-73 years, m: 33). Sometimes used as an isolated therapeutic procedure, V.C.S. may also follow stereotactic biopsies using Talairach's methodology. Serial stereotactic biopsies were performed in 15 out of 23 patients showing 11 tumoral lesion, two arachnoïdal cysts and two cryptic vascular malformations. Eight patients presented with an isolated aqueductal stenosis. Among the 12 non tumoral patients, seven had very large triventricular hydrocephalus (6 with a retroclival dilatation of the third ventricle) and 5 showed significant dilatation. Of the 11 tumoral patients, 7 had significant ventricular dilatation (1 with a protrusion of the floor of the third ventricle) and 4 with modest dilation. V.C.S. is done by creating an opening (diameter: 5-6 mm) in the floor of third ventricle with a fine forceps introduced through a tubular guide (diameter: 2.45 mm). The percutaneous double oblique transfrontal trajectory (drill-hole: 2.5 mm of diameter) passing through the foramina of Monro, avoids superficial and deep vessels visualised on the previous Stereoscopic Tele-Angiographic and Ventriculographic study. A systematic verification of the V.C.S. patency is made intraoperatively by injection of iodine contrast medium into the third ventricle. RESULTS: (non tumoral patients: 12) (m follow-up: 4 years): two patients needed a ventricular shunt after 3 and 1 months respectively, the first one because of an associated communicant hydrocephalus, the second because of a post-operative meningeal infection. Long-term clinical and CT-Scan follow-up showed that complete resolution (7 cases) or partial (2 cases) improvement of symptoms and signs was not accompanied by normalization of ventricular size, even though the dilatation was significantly reduced in 8 cases and to a lesser extent in 2. RESULTS: (tumoral patients: 11) (m follow-up: 3 years). Hydrocephalus was reduced in 6 cases and remained unchanged in 5. Two patients needed a ventricular shunt 2 years after the V.C.S.: 1 patient, because of a tumoral recurrence involving the region of the fenestration, the second patient because of adhesive arachnoiditis following reoperation for suspicion of recurrence, though this was found to be granulomatous inflammation. Two patients died as a result of their tumors at 2 and 6 years. CONCLUSION: Stereotactic V.C.S. is the treatment of choice for triventricular obstructive hydrocephalus even when there is no retroclival dilatation of the floor of the third ventricle.

Adolescent↗

The abundance and in vitro DNA binding of three cellular proteins interacting with the adenovirus EIIa early promoter are not modified by the EIa gene products.

Specific protein binding on the EIa-inducible adenovirus EIIa early (EIIaE) promoter was analyzed by the sensitive electrophoretic band-shift assay and by protection against DNase I digestion. Three factors were identified, and precise mapping of the cognate-binding sites revealed their correspondence to promoter elements essential for constitutive EIIaE transcription. One binds to the major upstream element located between -82 and -64 (with respect to the major EIIaE cap site), another appears to interact with sequences on either side of this region, and the last one binds to an element located further upstream. Comparison of the binding activities of the factors present in extracts from cells infected with wild-type adenovirus (adenovirus type 5) or with the EIa deletion mutant dl312 did not reveal striking differences. Not only were the general binding patterns indistinguishable, but the concentration of each of the identified factors as well as their affinity for the cognate-binding sites were unchanged. Our results suggest that the EIa-mediated activation of the EIIaE transcription complexes involves appropriate interactions between transcription factors, rather than their increased binding to DNA.

Adenovirus Early Proteins↗

Identical genomic footprints of the adenovirus EIIa promoter are detected before and after EIa induction.

Genomic DNase I footprinting was used to compare specific protein binding to the adenovirus type 5 early, EIa-inducible, EIIa promoter. Identical protection patterns of the promoter region were observed whether EIIa transcription was undetectable or fully induced. These results suggest that EIa-mediated transcriptional induction does not increase binding of limiting transcription factors to the promoter but rather that transactivation results from the proper interactions between factors already bound to their cognate sequences.

Adenoviridae↗

[Extradural hematoma in the Emergency Medical Assistance System and scanners. Comparison between 2 series at the Sainte-Anne Hospital Center].

The authors compare two groups of intracranial epidural hematomas treated in the Neurosurgical department of Sainte-Anne Hospital in Paris: the first group includes 262 patients operated upon between 1965 and 1977; the second group concerns 124 patients operated during the period 1979-1984. The mortality rate has been progressively diminishing from 1969 (50%) to 1984 (12.5%). Among the survivors, functional sequellae are still frequent; some improvement in the functional prognosis has although been noted; in the first group, 41% of patients are cured and 56% of them returned to work; in the second group, 50% are cured, and 62% returned to their professional activities. The detailed analysis of those data emphasizes the importance of CT-Scan and of the improvement of specialized neurosurgical intensive care; on the other hand, the particular role of an emergency care organisation, such as the SAMU, appears rather discreet referring to this type of pathology.

Adolescent↗

[Expression of MMTV proviruses in lymphopoietic organs of C3H Bi mice].

We show that transcription of MMTV proviruses takes place in lymphopoietic tissues (spleen, thymus) of C3H Bi mice, a strain with high incidence of tumors. This transcription is found in the spleen of 21 day old mice but is no longer detectable in the spleen of 4 month old mice. In the mammary tumor, the 3.8 kb RNA (24S) which encodes the viral envelope proteins is well transcribed whereas the 1.7 kb RNA (13 S) is barely detectable. In contrast, the 1.7 kb (13 S) is the major species present in the spleen of 21 day old mice. It appears that the 7.8 kb genomic RNA (35 S) is differentially spliced into a mature RNA of either 3.8 kb (24 S) or 1.7 kb (13 S). The function of the latter is still unknown, though it could encode a protein involved in the induction of carcinogenesis.

Animals↗

Influence of residual moisture and sealing atmosphere on viability of two freeze-dried viral vaccines.

This study demonstrated the complexity of the factors leading to changes in the infectivity titers of freeze-dried canine distemper and poultry infectious bronchitis viral vaccines. The change in moisture content during the storage period was an additional parameter which may influence the infectivity titer. The results emphasized the difficulty of predetermining variations in infectivity titers from the initial residual moisture. The analysis of the variations in infectivity titers during the storage of two vaccines led to the formulation of a hypothesis of the presence of two components of different thermostability. Moreover, the temporary increase in the infectivity titer of infectious bronchitis vaccine stored progressively dissociating during storage concurrent with a progressive inactivation of infectious particles.

Coronaviridae↗

Transcription of integrated MMTV LTR DNA in fibroblast clones is not associated with DNA methylation but with the integration site.

By transfecting 3T3 TK- fibroblasts with a plasmid DNA containing the MMTV LTR promotor and the thymidine kinase gene, we have isolated TK+ clones that contain only one copy of the recombinant DNA. The newly acquired DNA is integrated at different sites in each TK+ clones and can be amplified as a tandem repeat in some cases. The basal level of expression of the newly acquired LTR sequence is variable among the TK+ clones studied. Among those producing detectable amounts of MMTV RNA, we found that transcription is initiated from the LTR promotor and that the synthesis is stimulated by a short dexamethasone treatment. In addition, the presence of tandem repeated LTR DNA does not amplify the MMTV RNA synthesis. Endogenous LTR sequences have been found to be methylated, whereas we show that the newly integrated sequences, both as single copy and tandem repeats, remain unmethylated. Thus, non-methylation of MMTV LTR DNA is necessary but not significant to allow its transcription. Our results suggest that the level of LTR promotor activity could be modulated by the nature of its integration site within the cellular genome.

Animals↗

[Psychosurgical treatment of malignant OCD: three case-reports].

Surgery can be proposed for some patients affected by psychiatric diseases such as severe, disabling and refractory affective disorders (depression), OCD and chronic anxiety states. It can be performed after a period of evolution of minimum 5 Years and after all other classical treatments have failed. For the last Years, different stereotactic techniques have been used: capsulotomy, cingulotomy, subcaudate tractotomy and limbic leukotomy, performed by radiofrequency thermolesions or radiosurgery (g rays). In the case of OCD, these procedures are supposed to affect some of the neural circuits between the frontal lobes and different structures of the limbic system, considered as central to OCD symptoms. As they cause smaller cerebral lesions than earlier surgical techniques (mostly open surgery techniques), modern stereotactic approaches have less clinical side effects, primarily less deficit in emotional reactivity and motivation. This type of treatment offers some hope to patients seriously disabled by OCD. These surgeries and especially their main side effects are mentioned briefly in this Article. The most current indications for psychosurgery are severe OCD and chronic major depressive disorder. The level of stress should be significant and assessed by clinical and social functioning scale scores (for the OCD: Y-BOCS>25, GAF>50). Patients affected by demential disorders, sociopathic or paranoiac personality disorder, substance abuse should be excluded as well as patients aged 65 Years over and less than 18 Years. Several studies evaluating the results of the surgical treatment showed significant improvement in 54% of cases. and a moderate improvement in 27% of them. These results seem unchanged a few Years later in 56% of cases. Despite the lack of controlled trials of neurosurgery and several bias in published reports, evidence suggests that the condition of intractable OCD patients may improve after this surgery. Although capsulotomy and cingulotomy are mainly used, the superiority of any of these four surgical techniques has not been established yet. In this Article, we reported 3 "malignant" OCD cases treated by different psychosurgery techniques: 2 of the cases showed a clinical improvement, whereas the third did not -benefit from surgery. All of them were suffering of OCD since childhood with a gradual clinical impairment, unless the -second patient who presented a severe impairment following an accident causing a ten-day coma. In all three cases social consequences of OCD were important: negative socio-professional and family-life consequences and depressive complication with suicide risk. All patients remained unresponsive or showed a very transient reaction to the other forms of therapy, including varied pharmacotherapy (potentiation pharmacotherapy strategies included), intensive psychotherapy, behavioural therapy and electro-convulsive therapy. Pre- and post-operative assessment included neurological, radiological, psychometric and neuropsychological examination. The free and informed consent of the patient was always required before surgery, notifying the nature of the procedure, the potential risks and outcome. The first patient benefited of a bilateral anterior cingulotomy by thermocoagulation in stereotactic conditions, followed, four years later, by a second complementary one because of a relapse which occurred a few months after the first intervention. A clinical improvement was noticed over a period of two years, though it was not sufficient according to the patient. The second patient benefited of a stereotactic cingulotomy associated with a limbic leucotomy: it was initially efficient on OCD as well as on thymic symptoms. Nevertheless the positive evolution on OCD is not perceived by the patient and has not been assessed until now by clinical rating scales. Anterior cingulotomy is undergone in the third case, who showed a significant improvement. Despite clomipramine administered secondary to the surgery, a slight relapse of obsessive ideas was noticed six months later. The postoperative side effects were transient and regressive after a few months; they were observed especially in the case of tractotomy (oedema and transient frontal syndrome). On the whole, morbidity seemed more important with extensive lesions, whereas recurrence rate may be higher with smaller lesions. We did not observe any consequences on personality or on cognitive functions of these patients. No additional -deficits were observed after surgery. Further research is needed in order to determine the optimal site and size of the lesions in terms of efficacy and safety. Although psychosurgery is still controversial from an ethical view point, this treatment appears to be an ultimate solution for these severe disabled patients. Psychosurgery is a safe and relatively effective treatment which should be carried out by an expert multidisciplinary team in these disorders; surgery should be considered as part of an entire treatment program including an appropriate psychiatric rehabilitation part. Research in this field is currently focused on MRI-guided basal ganglia stimulation techniques which would allow to target specific structures in a reversible way.

Brain↗

Spontaneous disappearance of a spinal dural arteriovenous fistula.

A case of proved regression of an asymptomatic dural arteriovenous fistula is reported. At the time of diagnosis, myelography showed dilated perimedullary veins. Angiography demonstrated a radicular outflow from these veins to the epidural plexus. A follow-up angiogram 5 years later was normal.

Angiography↗