Biomedical subjects
Patrick Fenichel
Publications and source records attributed to Patrick Fenichel.
Sequestration of connexin43 in the early endosomes: an early event of Leydig cell tumor progression.
Connexins form gap junction channels that allow intercellular communication between neighboring cells. Compelling evidence has revealed that Cx are tumor-suppressor genes and reduced Cx expression has been related with uncontrolled cell growth in tumors and transformed cells. In the present study, we addressed Cx transcriptional and posttranscriptional regulations during the earlier stage of testicular tumors confined to Leydig cells in a transgenic mice model. In situ hybridization indicated that connexin43 (Cx43) mRNA was highly expressed either at early tumorogenesis (3 m) characterized by intense proliferation of Leydig cells, or at advanced tumorogenesis (6-7 m) when tumor cells completely invaded the testis. In contrast, Cx43 protein analyzed by Western blotting or classic immunohistochemical analyses was present at the beginning of tumor progression, but was dramatically reduced as tumor advanced. Application of high-resolution deconvolution microscopy to testis sections demonstrates that cells that proliferate exhibited an aberrant cytoplasmic Cx43 localization, in contrast to the expected plasma membrane Cx43 localization in normal Leydig cells. Dual immunofluorescence labeling with specific markers of cellular compartments shows that cytoplasmic Cx43 signal was mainly sequestered within early endosomes. Altogether, this study provides the first evidence that impaired Cx43 trafficking in endosomes is an early event associated with uncontrolled cell proliferation that could serve as a neoplastic marker.
Perchlorate: low dose exposure and susceptible populations.
Explore the source record for details and available documents.
[Male infertility due to azoospermia and in vitro fertilization assisted by ICSI. Findings based on a prospective study of our first 42 patients].
INTRODUCTION: Our experience of ICSI began in 1997. This study reviews our four-year experience based on 42 consecutive couples. MATERIAL AND METHOD: Between February 1997 and December 2000, 42 sterile couples due to male infertility were treated by ICSI. Surgical exploration and "open" gamete collection were proposed regardless of the predefined type of azoospermia, obstructive or non-obstructive. RESULT: Seventy one cycles were performed: ICSI used epididymal spermatozoa in 49 cycles, and testicular spermatozoa in 22 cycles. The fertilization rate was 76% for fresh semen and 87% for frozen semen. The fertilization rate was 88% for epididymal spermatozoa and 68% for testicular spermatozoa. 13 pregnancies were obtained (18.3%), 11 babies were born at term including 3 twin pregnancies. No significant difference was observed between fresh and frozen semen, or between obstructive and non-obstructive azoospermia. CONCLUSION: IVF-ICSI applied to sterility due to male infertility has revolutionized the management of sterile couples. However, as for any new procedure in medicine, we must be vigilant, as a sufficient follow-up is necessary to definitively evaluate the safety of ICSI, especially in terms of the risk of genetic abnormalities.