Biomedical subjects

D Bergeron

Publications and source records attributed to D Bergeron.

10 recordsLinked to original sources

PubMed1992

Analysis of proviruses integrated in Fli-1 and Evi-1 regions in Cas-Br-E MuLV-induced non-T-, non-B-cell leukemias.

The DNAs of the Cas-Br-E MuLV-induced leukemias always contain somatically acquired mink cell focus-forming (MCF) recombinant proviruses. MCF recombinants could be involved during leukemogenesis at both preleukemic times and in late-stage tumors. Among the Cas-Br-E-induced non-T-, non-B-cell leukemias, viral integrations were found in the Fli-1 and Evi-1 region in 71% (36 out of 51) and 22% (16 out of 72) of the tumors analyzed, respectively. As an approach to evaluate the contribution of Cas-Br-E MCF recombinant formation in cis-activation of proto-oncogenes, we analyzed the structure of the Fli-1- and Evi-1-associated proviruses by Southern blot hybridization. In Fli-1, we found that the proviruses, ecotropic as well as MCF, are all integrated within a very short DNA region immediately upstream of the initiator ATG, toward the 3' end of a 5' exon (Ben-David, Giddens, Letwin, and Bernstein, 1991, Genes Dev. 5, 908-918). All proviruses are oriented the same way, in the 5' to 3' transcriptional sense. Both provirus types are able to direct the Fli-1 expression to the same extent presumably via a promoter insertion mechanism. Most of the proviruses had no detectable deletion and contained both 5' and 3' LTR sequences with similar U3 sequences. MCF recombinants did not show any selective advantage over ecotropic proviruses for the Fli-1 locus since the frequency of ecotropic to MCF-recombinant virus at the Fli-1 locus was identical to that observed at any other locus. This suggests that the formation of these MCF recombinants is not essential for activation of Fli-1 and that ecotropic Cas-Br-E already possesses the required sequences for full cis-activation of Fli-1. On the other hand, in Evi-1, there is a strict selection for ecotropic proviruses. Presumably, viral genetic elements outside of the U3 region could be critical for the Evi-1 cis-activation.

Animals↗

PubMed1992

Determinants of thymotropism in Kaplan radiation leukemia virus and nucleotide sequence of its envelope region.

Radiation leukemia viruses (RadLVs) are a group of murine leukemia viruses which are induced by radiation and cause T-cell leukemia. Viral clones isolated from the BL/VL3 lymphoid cell line derived from a thymoma show variable tropism and leukemogenic potential. We have constructed chimeric viruses by in vitro recombination between two viruses, a RadLV that is thymotropic and an endogenous ecotropic virus that is nonthymotropic. We show here that, in contrast to thymotropism determinants identified previously, which lie in the long terminal repeat (LTR), it is the envelope region that is responsible for the thymotropism of BL/VL3 RadLV. The nonthymotropic virus which we have rendered thymotropic by transfer of the env region of RadLV in the present study has been shown previously to become thymotropic when the LTR of another thymotropic virus is inserted in its genome. Thus, the LTR and envelope gene may be involved in complementary action to lead to thymotropism.

Amino Acid Sequence↗

PubMed1991

High-yield method for directional cDNA library construction.

Improvement of a cDNA synthesis procedure using a single stranded (ss) vector primer [Bellemare et al., Gene 52 (1987) 11-19] is reported. This vector (pPBS27), upon linearization with XbaI using an appropriate restriction site-directed fragment, releases a thymidilic tail used to prime cDNA synthesis. DNA polymerase I and RNase H replace the RNA strand and replicate the vector before double-stranded (ds) blunt-end ligation with T4 DNA ligase. More than 10(7) cfu/microgram of vector can be obtained with an efficient transformation protocol using either globin-encoding or 7.5-kb poly(A)-tailed RNA. This improved cloning method is easier, faster and a few hundred times more efficient than the original procedure as it involves ds rather than ss DNA for transformation.

Base Sequence↗

PubMed1991

The human homolog of the mouse common viral integration region, FLI1, maps to 11q23-q24.

FLI1 is a common mouse viral integration region in virus-induced leukemias and lymphomas. Using an evolutionarily conserved mouse probe and Southern hybridization to (rodent x human) somatic cell hybrid DNAs, the human homolog of FLI1 has been shown to lie on a fragment of chromosome 11 flanked on the centromeric side by the acute lymphoblastic leukemia-associated t(4;11)(q21;q23) translocation breakpoint and on the telomeric side by the Ewing- and neuroepithelioma-associated t(11;22) (q24;q12) breakpoint.

Animals↗

PubMed1991

Identification of a common viral integration region in Cas-Br-E murine leukemia virus-induced non-T-, non-B-cell lymphomas.

The Cas-Br-E murine leukemia virus is a nondefective retrovirus that induces non-T-, non-B-cell lymphomas in susceptible NIH/Swiss mice. By using a DNA probe derived from Cas-Br-E provirus-flanking sequences, we identified a DNA region, originally called Sic-1, rearranged in 16 of 24 tumors analyzed (67%). All proviruses were integrated in a DNA segment smaller than 100 bp and were in the same 5'-to-3' orientation. Ecotropic as well as mink cell focus-forming virus types were found integrated in that specific DNA region. On the basis of Southern blot analysis of somatic cell hybrids and progeny of an interspecies backcross, the Sic-1 region was localized on mouse chromosome 9 near the previously described proto-oncogenes or common viral integration sites: Ets-1, Cbl-2, Tpl-1, and Fli-1. Restriction map analysis shows that this region is identical to the Fli-1 locus identified in Friend murine leukemia virus-induced erythroleukemia cell lines and thus may contain sequences also responsible for the development of mouse non-T-, non-B-cell lymphomas.

Animals↗

PubMed1990

[A new space for feminine desire].

Psychoanalitical literature evolved around the idea of a space for desire structured according to the boy-mother relationship model. Is the feminine clinical approach, together with the historical contribution of feminism, discovering a new space for feminine desire? The psychotic female, for whom the role of the father has no meaning in the mother's discourse, refuses the Law as a symbol of social authority. As for the hysteric female, she does not rely on the Father as a safeguard against the emptyness that lies behind the Laws and the beliefs of men. In its own way, feminism adopts these positions of psychotic rejection and hysteric contestation by projecting them on to the social landscape. Furthermore, feminism requires new forms of social interaction that embody the esthetical space women need to experience life as full-fledged citizens.

Cultural Characteristics↗

PubMed1989

Cystic schwannoma of the brainstem.

A rare case of cystic schwannoma occurring in the brainstem in the absence of von Recklinghausen's disease is reported. This appears to be the first case in the literature of a cystic schwannoma ever described in this location. While the exact origin of this tumor in this unusual location remains uncertain, different hypotheses are discussed and the possible origin of this tumor from perivascular elements in the brainstem is seriously considered.

Brain Neoplasms↗

PubMed1989

[Post-intubation right paratracheal abscess. Apropos of a case].

We report the case of a young woman who had undergone a difficult emergency intubation and rapidly developed a mediastinal collection of pus. Mediastinoscopy, requested for diagnostic purposes, was also therapeutic as it drained the abscess. The patient received a course of antibiotics and was cured without sequelae. Accidents of tracheal intubation are severe, especially when unrecognized. They often include perforation of the oesophagus resulting in mediastinitis or abscess with an estimated 30 to 40% mortality rate, and they constitute a medico-surgical emergency. In the case reported here mediastinoscopy was crucial, but the theoretical value of computerized tomography must be stressed since this method not only detects the lesion but is also used to perform a guided drainage.

Abscess↗

PubMed1976

Tracheobronchopathia osteochondroplastica.

Tracheobronchopathia osteochondroplastica is a rare disorder characterized by the projection of ossified formations into the trachea and bronchi. Unlike most cases, which are reported because of incidential postmortem findings, our patient presented with a slowly resolving pneumonia. The diagnosis was suspected by radiographic evaluation and bronchoscopic findings, then confirmed by histopathologic studis of a tracheal biopsy specimen. Pulmonary function studies were normal, except for flow-volume loops, which provided information for diagnosis and follow-up.

Aged↗

PubMedDate not supplied

Low-grade myxoid chondrosarcoma of the base of the skull: CT, MR, and histopathology.

A retrospective CT, MR, and histopathologic study was performed in five patients with histologically verified low-grade myxoid chondrosarcoma of the base of the skull. In four patients, the tumor originated off the midline and was associated with bone destruction at the petrous apex near the petrooccipital fissure. Tumor extent included the cerebellopontine angle in three patients and the parasellar area in two patients. The fifth tumor originated on the midline and was associated with destruction at the dorsum sellae. Three tumors contained calcifications, whereas two lesions were mostly isodense with brain on CT scan. All tumors were hypointense on T1-weighted MR images and very intense on T2-weighted images except for areas of signal void consistent with calcifications. Light microscopy revealed islands of mature hyaline cartilage in an abundant myxoid ground substance. Histology and immunocytochemical analysis were consistent with a low-grade myxoid chondrosarcoma. The CT and MR features of low-grade myxoid chondrosarcoma are comparable with those of chordoma. Chordoma usually arises from the midline, but cases with origin from the lateral portion of the clivus or the petrous apex have been described. Low-grade myxoid chondrosarcoma has distinct histologic and immunocytochemical features and includes lesions formerly called "chondroid chordomas."

Adolescent↗