Biomedical subjects

R Dubois

Publications and source records attributed to R Dubois.

At least 55 records · Page 3Linked to original sources

PubMed1997

[New data on the role of glycoproteins in germ cell chemotactism in chick embryo].

Using peroxidase-coupled Concanavalin A during the organogenesis of embryonic gonads, we show that there is a positive correlation between the expression of specific glycoprotein complexes by germ cells and the migratory activity of these cells. An experimental artifice enabled us to subject 'sedentary' primary gonocytes in the undifferentiated gonad to the attractive influence of a young germinal epithelium. Under these conditions, chemotactism was reactivated in the primary gonocytes, in conjunction with a stimulation of their expression of glycosylated complexes.

Animals↗

PubMed1997

[Pheochromocytoma: pediatric features].

Pheochromocytoma is a rare tumor in children which explains, together with its miscellaneous symptomatology, why the diagnosis may be delayed. The localization of the tumor(s) rests mainly on MIBG scintigraphy, and CT scan and/or magnetic resonance imaging. Thanks to a systematic preoperative treatment of hypertension and major progress in anesthesia, the operative mortality of pheochromocytomas in children is nowadays very low. Nevertheless two major problems remain: 1) the difficulty of diagnosing and treating the malignant forms, 2) the high frequency of recurrences, sometimes many years after the removal of the primary tumor. A regular long term supervision is therefore necessary after the surgical treatment.

Adrenal Gland Neoplasms↗

PubMed1997

[Malformations of Wolffian duct derived male genital organs (epididymis, vas deferens, seminal vesicules, ejaculatory ducts)].

OBJECTIVES: To analyse embryological phenomena, in order to define a practical approach to management. METHODS: The authors reviewed the files of eight boys with an abnormality of Wolffian duct derived genital organs, consisting of three cases of vas deferens agenesis, two of which were accompanied by homolateral renal agenesis, one case of ectopic vas deferens with contralateral renal agenesis, three cases of duplicated vas deferens and one congenital seminal vesicle cyst with renal agenesis. DISCUSSION: Congenital malformations of the epididymis consist of cysts and agenesis or partial atresia. Cysts essentially raise a problem of differential diagnosis. Treatment is only required in the case of severe discomfort. Vas deferens agenesis is the commonest lesion, an incidental finding in children. An experimental treatment is proposed in adults. Duplications, interdeferential communications and deferentomegaly are much rarer lesions. Seminal vesicle cysts are well visualized by transrectal ultrasonography and should be treated surgically. Lastly, ejaculatory ducts may present urethroseminal reflux or may be ectopic. CONCLUSION: The possibility of absent or ectopic vas deferens should be considered in the case of unilateral renal agenesis. Vas deferens agenesis justifies examination of the contralateral side and investigation to exclude renal agenesis. Congenital cysts of the epididymis only require surgery when they are symptomatic. The presence of ipsilateral renal agenesis should be investigated in the case of cystic dilatation of the seminal vesicle.

Adolescent↗

PubMed1996

Altered sensory processing in the somatosensory cortex of the mouse mutant barrelless.

Mice homozygous for the barrelless (brl) mutation, mapped here to chromosome 11, lack barrel-shaped arrays of cell clusters termed "barrels" in the primary somatosensory cortex. Deoxyglucose uptake demonstrated that the topology of the cortical whisker representation is nevertheless preserved. Anterograde tracers revealed a lack of spatial segregation of thalamic afferents into individual barrel territories, and single-cell recordings demonstrated a lack of temporal discrimination of center from surround information. Thus, structural segregation of thalamic inputs is not essential to generate topological order in the somatosensory cortex, but it is required for discrete spatiotemporal relay of sensory information to the cortex.

Animals↗

PubMed1996