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E Leblanc

Publications and source records attributed to E Leblanc.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Clinical aspects of primary cancer of the fallopian tube. A retrospective study of 20 cases].

OBJECTIVES: From a review of 20 cases of primary carcinoma of the fallopian tube, we stress the various clinical aspects of the disease and discuss the possibilities of a preoperative diagnosis. MATERIALS AND METHODS: A retrospective study covering the period between 1982 and 1996. An analysis of the different etiological factors mentioned in the literature, of the physical signs and symptoms of the carcinoma, of the patients' age and hormonal status as well as the role of additional investigations was conducted. RESULTS: The average age of the patients was 62.3 years, 90% of the women had reached menopause and 15% were nullipara. A history of salpingitis was noted in 5% of the patients and another 5% had infertility problems. 20% of the patients had suffered from another carcinoma. Metrorrhagia was the most frequent clinical finding revealing the disease (55%) followed by abnormal secretions of blood stained liquid (15%). Hydrops Tubae Profluens was not observed in this series. The main complementary investigations performed were pelvic ultrasound scanning and hysterosalpingography, preoperative diagnosis was possible in 15% of cases; diagnosis was made during the operative procedure in 45% of cases and by pathologic examination in the remaining 40% of patients. CONCLUSION: Primary carcinoma of the fallopian tube is a rare form of cancer of unknown aetiology. Clinical signs are often unrelated and sometimes misleading; however, preoperative diagnosis is possible if one keeps in mind the existence of this carcinoma.

Aged↗
PubMed1998

Residues involved in co-factor and substrate binding of the short-chain dehydrogenase/reductase PTR1 producing methotrexate resistance in Leishmania.

The Leishmania short-chain dehydrogenase/reductase gene ptr1 has been isolated while characterizing antifolate-resistant Leishmania mutants. PTR1 is active as a tetramer and can reduce pterins and folates. PTR1 has several of the hallmarks of the short chain dehydrogenase/reductase family, including a glycine rich co-factor binding site at its N-terminus, and the consensus catalytic site TyrXaa3Lys. To start probing the structure/function of PTR1, we have generated by site-directed mutagenesis five mutants, either in the co-factor-binding site, Y38D or in the catalytic site Y195F, Y195W, K199R or in a PTR1-specific region, Y175F. The mutated versions of PTR1 were studied in vivo in Leishmania and at the biochemical level using purified proteins. The Y175F mutant showed properties similar to wild-type PTR1 in every aspect tested, but all the other mutants were inactive even if they were purified as tetramers. To test the ability of the mutated PTR1 versions to bind its co-factor and substrates, trypsin digestion experiments were carried out under conditions upon which binding will prevent wild-type PTR1 of being digested by trypsin. The wild-type PTR1 as well as Y175F and Y195F mutants were protected against trypsin digestion whereas Y38D and K199R mutants were not. Mutations in regions involved in co-factor binding (Y38D) or in catalytic site (K199R) altered the binding of the ligands, explaining why those protein versions are inactive.

Amino Acid Sequence↗
PubMed1998

An objective experimental assessment of the learning curve for laparoscopic surgery: the example of pelvic and para-aortic lymph node dissection.

OBJECTIVES: To date the number of procedures required to become competent to perform new laparoscopic surgical techniques is not known. STUDY DESIGN: The pig model was chosen for assessment of the learning curve associated with an advanced laparoscopic procedure. A unilateral laparoscopic pelvic lymphadenectomy was performed by two residents and a laparoscopic para-aortic lymphadenectomy was performed by a fellow on a series of 20 pigs. The quality of the dissection was checked by immediate laparotomy by an independent observer. RESULTS: The operative objectives were: (a) There should be less than 5% residual lymph nodes. (b) The operating time should be less than 30 min for pelvic and less than 100 min for para-aortic lymphadenectomy. (c) Avoiding conversion because of complications. This target was achieved after 7 and 9 pigs respectively for pelvic lymphadenectomy and after 14 pigs for para-aortic lymphadenectomy. CONCLUSION: It is feasible to assess the learning curve of trainee surgeons while performing laparoscopic pelvic and para-aortic lymphadenectomy on pigs. A training programme such as this should prevent complications due to inexperience and should satisfy ethical and medico-legal considerations.

Animals↗
PubMed1998

[Comparative study of tumor evaluation with computerized tomography and surgery in ovarian cancer].

PURPOSE: To evaluate the results of an abdomino-pelvic scan in cancers of the ovary in comparison with surgery. MATERIAL AND METHODS: We reviewed the observations concerning patients operated on for malignant tumors of the ovary between January 1992 and April 1995 in our anti-cancer center. We selected 32 patients who had had both a complete surgical abdominal exploration (laparotomy or laparoscopy) and an abdominal pelvic scan in the preceding months. We divided the abdomen into 33 areas and compared the scan of each with the surgical findings. Two cancer radiologists, including one gynecology specialist, studied the imaging separately. Neither knew the results of the surgical observations. RESULTS: Imaging findings varied with localization tumor size and presence or not of ascites radiologists. For certain localization, detection of lesions was difficult for both readers (pancreas, spleen, stomach), for others, recognition improved with experience (bowel, diaphragm, colon). CONCLUSION: The clinician must be aware of the variability of ovarian cancer assessment by CT scan, particularly if imaging alone is being used to guide treatment.

Abdominal Neoplasms↗
PubMed1997

Pterin and folate reduction by the Leishmania tarentolae H locus short-chain dehydrogenase/reductase PTR1.

Overproduction of the short-chain dehydrogenase/reductase PTR1 confers resistance to the dihydrofolate reductase inhibitor methotrexate in the protozoan parasite Leishmania. Genetic analysis has previously implicated PTR1 in pterin and folate metabolism. PTR1 was purified from a fusion protein expressed in Escherichia coli. Purified PTR1 exhibits NADPH-dependent biopterin, dihydrobiopterin, folate, and dihydrofolate reductase activities. The highest activity was found with the most oxidized pterins. The active protein was found to be a tetramer as demonstrated by gel-filtration chromatography. Kinetic constants (K(m)), as determined by double-reciprocal plots, were calculated for NADPH and for several of PTR1's substrates. The PTR1 of Leishmania tarentolae had a K(m) of 16.9 microM for the cofactor NADPH and K(m) values ranging from 3.5 to 85 microM for the various substrates. The dissociation constant (KD), as determined by fluorescence titration, for NADPH was estimated to be 130 microM. The biochemical characterization of this important and novel enzyme involved in folate and pterin metabolism of Leishmania should be useful for structure-function analysis and for developing specific inhibitors against this putative important chemotherapeutic target.

Animals↗
PubMed1997

Accuracy and safety of laparoscopic lymphadenectomy: an experimental prospective randomized study.

INTRODUCTION: The goal of this study was to investigate the accuracy and safety of bilateral pelvic and paraaortic lymphadenectomy performed via transperitoneal laparoscopy (LS) compared to laparotomy (LT) in a porcine model. MATERIALS AND METHODS: Fifteen adult, female hogs underwent LS and 15 underwent LT. A complete pelvic and paraaortic lymphadenectomy was performed in each animal by an experienced surgeon. Lymph nodes were counted by a pathologist in each case. Operative times were reviewed and included all procedures performed. The intraoperative complications were noted. Four weeks after the lymphadenectomy, the animals underwent exploratory laparotomy, and intraperitoneal adhesions were quantified. RESULTS: Thirty animals were evaluable. The average total number of lymph nodes retrieved by LS was 16.9 +/- 3.8, which was not statistically (P = 0.77) different from 16.5 +/- 4.9 nodes in LT. The average operating time in LT was 60 +/- 16 min compared with 128 +/- 24 min in LS. Twenty-eight animals were evaluable for adhesion formation. The average adhesion scores observed in anterior abdominal wall (P = 0.0006), paraaortic (P = 0.0005), right (P = 0.015), and left (P = 0.0324) iliac areas after LS were uniformly lower than after LT. DISCUSSION: This study indicates that laparoscopic pelvic and paraaortic lymphadenectomy is a safe and effective procedure. The node yield is similar for both approaches. The transperitoneal laparoscopy pelvic and paraaortic lymphadenectomy may not induce the degree of adhesion formation associated with laparotomy.

Animals↗
PubMed1996

[Endometrial cancer: total simple hysterectomy or radical hysterectomy? Abdominal or vaginal route?].

Total abdominal hysterectomy and bilateral salpingo-oophorectomy has long been the standard surgical treatment for endometrial cancer. Radical hysterectomy is not useful in stage I. in women with extreme obesity and medical risk factors, vaginal hysterectomy is recommended. Laparoscopy-assisted vaginal hysterectomy complete the oncologic treatment if lymphadenectomy is necessary.

Endometrial Neoplasms↗
PubMed1995

Functional PET scanning in the preoperative assessment of cerebral arteriovenous malformations.

We have evaluated positron emission tomography (PET) scanning during sensory stimulation or during the performance of auditory, visually based or expressive language tasks (activation PET scanning) to determine its reliability in establishing the relationships of cerebral arteriovenous malformations (AVMs) to the ambient cortex in 10 patients. Five patients with a central AVM underwent activation PET scanning combined with three-dimensional MRI during vibrotactile stimulation of the contralateral hand, and 5 patients with AVMs in or around speech areas were similarly scanned during a language task. Vibrotactile stimulation identified the post-central gyrus, establishing the relationship of the AVM to the central region. The results of language activation were specific to the modality (visual, auditory, articulate) on which the task was based. Sensory PET activation scanning is reliable in identifying the pre- and post-central gyri and useful in assessing AVMs in and around the central region. A greater understanding of results in normal controls for specific visual, auditory, and expressive language tasks is necessary before language activation PET scanning can be confidently applied to clinical cases.

Brain↗
PubMed1994

Changes in folate and pterin metabolism after disruption of the Leishmania H locus short chain dehydrogenase gene.

The short chain dehydrogenase gene ltdh, which is derived from the H locus of Leishmania, confers high level resistance to the dihydrofolate reductase inhibitor methotrexate via a novel mechanism. Resistance is correlated with LTDH overproduction. High level resistance of ltdh transfectants was observed even in poor media where reduced folates are essential for the synthesis of thymidylate precursors. The ltdh transfectants were also capable of growing for several passages, at slightly reduced rates, in unsupplemented folate-deficient medium (fdDME-L), unlike the wild-type cells that could grow only in fdDME-L if supplemented with various folates or pterins. An homozygous ltdh mutant was obtained by gene targeting. This mutant became hypersensitive to methotrexate, but unlike wild-type cells, methotrexate toxicity could not be circumvented by the addition of thymidine. Although the homozygous mutant was capable of growing in fdDME-L supplemented with folate derivatives, it lost its ability to thrive in fdDME-L supplemented with pterins. Our results support the model in which LTDH is a key enzyme responsible for the conversion of a pterin derivative into an essential cofactor. This essential cofactor can also be converted into reduced folates at sufficient levels for growth when LTDH is overproduced, rendering dihydrofolate reductase dispensable. The novelty and uniqueness of LTDH opens the possibility of developing parasite-specific inhibitors.

Animals↗
PubMed1994

[Place of celiosurgery in the extensive diagnosis of gynecologic cancers].

Laparoscopic surgery occupies an increasingly important place in the diagnosis and staging of gynaecological cancers. It allows repeated complete investigation of the abdomen and retroperitoneum: macroscopic examination of the peritoneum, cytology, biopsies, infracolonic omentectomy, appendicectomy, pelvic and para-aortic lymphadenectomy, without interfering with therapeutic procedures (simple or radical hysterectomy) which can be associated. In cancers of the endometrium, it is part of a surgical strategy associating vaginal hysterectomy. In ovarian cancers, it is essentially applied to restaging of insufficiently explored apparent stage I tumours. In operable cervical cancer, it guides the therapeutic protocol and surgical indication by allowing interiliac lymphadenectomy. In advanced cervical cancers, it is used to detect para-aortic lymph nodes.

Endometrial Neoplasms↗
PubMed1993

[Pelvic endoscopic lymphadenectomy in the assessment of early cancer of the uterine neck: survey of 25 French hospital centers].

Accurate staging of invasive cervical cancer is essential to its adequate treatment. Current clinical staging of cervical cancer is inaccurate, particularly for lymph-nodes evaluation. At reduced cost and risks laparoscopic pelvic lymphadenectomy allows accurate detection of lymph-node metastases. Its place in the staging of early cervical cancer is being evaluated. Our inquiry, multicentric and including more than 500 laparoscopic pelvic lymphadenectomies, leads to the conclusion that this technique is accurate and is associated with a reduced but variable morbidity depending on the technique and operator's ability. The implications of the results of laparoscopic lymphadenectomy in the type and modalities of subsequent treatment are discussed.

Female↗
PubMed1991

Laparoscopic pelvic lymphadenectomy in the staging of early carcinoma of the cervix.

Laparoscopic pelvic lymphadenectomy was performed in 39 patients. An incision of the peritoneum between the round and infundibulo-pelvic ligament on each side gave access to the retroperitoneal space. Subsequently, laparoscopic surgery allowed precise dissection of external and internal iliac vessels, umbilical artery, and obturator nerve. The peritoneum was left open, and the lymph was drained into the peritoneal cavity. No lymphocele was observed. Three to 22 (mean, 8.7) nodes were removed, and there was no significant morbidity. Sensitivity and specificity were 100% in this preliminary experience. It is thus possible to remove the first-line regional lymph nodes of the cervix for pathologic examination. Because "skip" metastases are quite rare in early cervical carcinoma, the risk of missing a positive node is low. Brachytherapy alone, vaginal surgery, or, in microinvasive carcinoma, conization alone can be applied safely without the need of a staging laparotomy in cases with negative nodes.

Biopsy↗