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P Poncet

Publications and source records attributed to P Poncet.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Expression of VH11-gene family in hybridoma collections from peritoneum and spleen: differential correlation with BrMRBC reactivity.

Hybridoma collections from spleen or peritoneal cells of newborn or adult individuals were screened by RNA hybridization for expression of the VH11-gene family using a V-region probe VCP12, which encodes anti-BrMRBC antibodies. No VH11 expression was observed in hybridomas derived from newborn spleen cells in either BALB/c, NZB or (CBA/N x BALB/c) F1 mice (0/93). Adult NZB and BALB/c spleen cell collections contained only one hybridoma expressing VH11 (1/242). Interestingly, however, the VH11-positive hybridoma showed no anti-BrMRBC reactivity, while one anti-BrMRBC clone in the same collection expressed a Q52 VH gene. In contrast, hybridomas derived from peritoneal cells showed an absolute correlation between expression of VH11 genes and anti-BrMRBC reactivity (15/32). The high expression in the peritoneal cavity of such cells is likely the result of local positive selection.

Animals↗
PubMedDate not supplied

Antibody-mediated endocytosis of G250 tumor-associated antigen allows targeted gene transfer to human renal cell carcinoma in vitro.

Specific gene transfer into targeted tumor cells remains a critical issue for the development of systemic gene therapy protocols. With this end in view, we have tested the possibility of selectively directing genes to tumor cells through the recognition of tumor-associated antigens (TAA). This was approached in vitro on four human renal cell carcinoma (RCC) lines by means of the highly specific mouse G250 monoclonal antibody (mAb) chemically conjugated to a plasmid DNA conveying a reporter activity. This mAb directed to a TAA that is present on 95% of primary RCCs and on 60% of metastatic human RCCs was extensively characterized, including during clinical trials. Epifluorescence microscopy analysis indicated that upon specific binding to G250 TAA, G250 mAb alone or conjugated to plasmid DNA was internalized by an active endocytic process and colocalized with the transferrin concentrated in the late recycling perinuclear compartment. We also observed that both unconjugated G250 mAb or G250 mAb conjugated to plasmid DNA remained in the perinuclear region of the cells for > or = 20 hours and were not rapidly translocated to lysosomes or recycled to the plasma membrane. In contrast, unconjugated plasmid DNA was not internalized. After transfection of G250 TAA-positive RCC lines with G250 mAb conjugated to a plasmid cDNA encoding mouse interleukin-2, a significant and sustained production of mouse interleukin-2 protein was detected from days 5-15 and was abrogated by inhibiting the internalization process. Altogether, our data showed that endocytosis of G250 TAA should be the basis of gene transfer to RCC, suggesting that targeting of TAA capable of internalization may be the basis of new approaches for designing alternative cancer gene therapy procedures.

Animals↗
PubMedDate not supplied

[Value of the cytologic diagnosis of adenopathies by aspiration biopsy. Cytohistologic comparison of 1756 cases].

The value of the cytologic diagnosis by aspiration needle biopsy is analysed in a series of 1756 adenopathies, verified by histological examination (1311 malignant nodes and 445 inflammatory or normal lymph nodes). The result is that a large number of lymph node tumours, either primary or secondary, are identified by the cytologic examination (from 77% to 91% of the cases according to the explored zone). Furthermore the virtually non existent percentage of false positive results (3% of the cases) proves the great accuracy of this method in the diagnosis of malignancy. In contrast, the diagnosis of benign nature must never be stated without biopsy (2% to 4% of the cases are erroneous by negative according to the explored zone). Indeed, even if benign cells are obtained, nothing allows to eliminate a malignant tumour or a limited inflammatory zone, not reached by the needle.

Axilla↗
PubMedDate not supplied

[Aberrant course of the intrapetrous internal carotid in the eardrum. Analysis of a personal case. Review of the literature (author's transl)].

A new case of aberrant course of the internal carotid artery in the eardrum described, with the particular features of being associated with progressive chronic otitis and a picture of multiple malformations. Diagnosis of the abnormality of the course and its topographical limits, using tomography and angiography, led to a successful antroatticotomy. On the basis of a review of the literature, the authors describe the main criteria of the clinical and radiological diagnosis and present the current pathogenic theories of the mechanism of this congenital abnormality.

Adolescent↗