Search PubMed⌕ Search

Biomedical subjects

Christophe Laurent

Publications and source records attributed to Christophe Laurent.

At least 19 recordsLinked to original sources
PubMed2006

Relationship between the severity of hepatitis C virus-related liver disease and the presence of Helicobacter species in the liver: a prospective study.

AIM: To determine the presence of Helicobacter species DNA in the liver of chronic hepatitis C (CHC) patients with and without cirrhosis as compared to controls, and to identify the bacterial species involved. METHODS: Seventy-nine consecutive patients (HBV and HIV negative) with a liver sample obtained after liver biopsy or hepatic resection were studied: 41 with CHC without cirrhosis, 12 with CHC and cirrhosis, and 26 controls (HCV negative). Polymerase chain reactions (PCRs) targeting Helicobacter 16S rDNA and species-specific were performed on DNA extracted from the liver. A gastric infection with H pylori was determined by serology and confirmed by 13C-urea breath test. RESULTS: Overall, Helicobacter 16S rDNA was found in 16 patients (20.2%). Although positive cases tended to be higher in CHC patients with cirrhosis (41.6%) than in those without cirrhosis (17.0%) or in controls (15.4%), the difference was not statistically significant (P = 0.08). H pylori-like DNA was identified in 12 cases and H. pullorum DNA in 2, while 2 cases remained unidentified. Gastric infection with H pylori was found in only 2 of these patients. CONCLUSION: Our results do not confirm the association of Helicobacter species DNA in the liver of CHC patients with advanced liver disease. The lack of correlation between positive H pylori serology and the presence of H pylori-like DNA in the liver may indicate the presence of a variant of this species.

Biopsy↗
PubMed2006

Efforts to improve local control in rectal cancer compromise survival by the potential morbidity of optimal mesorectal excision.

BACKGROUND: The technique of total mesorectal excision (TME) increases the risk of anastomotic leakage. The impact of postoperative morbidity of TME on longterm survival has never been described. We retrospectively analyzed factors that might influence survival after TME for rectal cancer, including postoperative morbidity. STUDY DESIGN: From 1994 to 2001, 300 patients (192 men and 108 women; mean age, 64 years) had TME for rectal cancer. Preoperative radiotherapy was given in 202 patients. Age, gender, tumor height, size and circular invasion of the tumor, pathologic tumor and nodal status, distal and circumferential margins, number of lymph nodes analyzed, type of surgery, postoperative pelvic sepsis, preoperative radiotherapy, and adjuvant chemotherapy were examined; their association with overall and disease-free survival was evaluated by the log-rank test in univariate analysis and by multivariable Cox proportional hazards analysis. RESULTS: Postoperative morbidity was 38% (113 of 300 patients) and included 18% (54 of 300 patients) pelvic sepsis. The local recurrence rate was 6% (18 of 300 patients), and the distant metastasis rate was 24% (73 of 300 patients). Recurrence was three times more frequent distally than locally, including patients with pelvic sepsis The 5-year overall and disease-free survival rates were 72% and 60%, respectively. Independent predictors of overall survival were age older than 64 years (odds ration [OR]=2.19, 95% CI 1.32 to 4.17), pelvic sepsis (OR=2.06, 95% CI 1.10 to 3.87), circumferential surgical margin (OR=3.19, 95% CI 1.67 to 6.09), pathologic tumor (OR=2.69, 95% CI1.23 to 5.88), and nodal status (OR=3.18, 95% CI 1.79 to 5.64). Independent predictors of disease-free survival were pelvic sepsis (OR=2.17, 95% CI 1.31 to 3.58), circumferential surgical margin (OR=2.61, 95 CI 1.52 to 4.49), pathologic tumor (OR=1.82, 95% CI 1.04 to 3.20), and nodal status (OR=2.67, 95% CI 1.68 to 4.23). Patients with pelvic sepsis had a 5-year disease-free survival of 39% compared with 65% without pelvic sepsis (p<0.001). CONCLUSIONS: After TME for rectal cancer, pelvic sepsis is a common complication that is associated with increased risk of distant recurrence and decreased longterm survival. Efforts are necessary to decrease postoperative morbidity in surgical treatment of rectal cancer.

Adenocarcinoma↗
PubMed2006

Genotype-phenotype correlation in hepatocellular adenoma: new classification and relationship with HCC.

Hepatocellular adenomas are benign tumors that can be difficult to diagnose. To refine their classification, we performed a comprehensive analysis of their genetic, pathological, and clinical features. A multicentric series of 96 liver tumors with a firm or possible diagnosis of hepatocellular adenoma was reviewed by liver pathologists. In all cases, the genes coding for hepatocyte nuclear factor 1alpha (HNF1alpha) and beta-catenin were sequenced. No tumors were mutated in both HNF1alpha and beta-catenin enabling tumors to be classified into 3 groups, according to genotype. Tumors with HNF1alpha mutations formed the most important group of adenomas (44 cases). They were phenotypically characterized by marked steatosis (P < 10(-4)), lack of cytological abnormalities (P < 10(-6)), and no inflammatory infiltrates (P < 10(-4)). In contrast, the group of tumors defined by beta-catenin activation included 13 lesions with frequent cytological abnormalities and pseudo-glandular formation (P < 10(-5)). The third group of tumors without mutation was divided into two subgroups based on the presence of inflammatory infiltrates. The subgroup of tumors consisting of 17 inflammatory lesions, resembled telangiectatic focal nodular hyperplasias, with frequent cytological abnormalities (P = 10(-3)), ductular reaction (P < 10(-2)), and dystrophic vessels (P = .02). In this classification, hepatocellular carcinoma associated with adenoma or borderline lesions between carcinoma and adenoma is found in 46% of the beta-catenin-mutated tumors whereas they are never observed in inflammatory lesions and are rarely found in HNF1alpha mutated tumors (P = .004). In conclusion, the molecular and pathological classification of hepatocellular adenomas permits the identification of strong genotype-phenotype correlations and suggests that adenomas with beta-catenin activation have a higher risk of malignant transformation.

Adenoma, Liver Cell↗
PubMed2005

Fe/Co alloys for the catalytic chemical vapor deposition synthesis of single- and double-walled carbon nanotubes (CNTs). 1. The CNT-Fe/Co-MgO system.

Mg(0.90)Fe(x)Co(y)O (x + y = 0.1) solid solutions were synthesized by the ureic combustion route. Upon reduction at 1000 degrees C in H2-CH4 of these powders, Fe/Co alloy nanoparticles are formed, which are involved in the formation of carbon nanotubes, which are mostly single and double walled, with an average diameter close to 2.5 nm. Characterizations of the materials are performed using 57Fe Mössbauer spectroscopy and electron microscopy, and a well-established macroscopic method, based on specific-surface-area measurements, was applied to quantify the carbon quality and the nanotubes quantity. A detailed investigation of the Fe/Co alloys' formation and composition is reported. An increasing fraction of Co2+ ions hinders the dissolution of iron in the MgO lattice and favors the formation of MgFe2O4-like particles in the oxide powders. Upon reduction, these particles form alpha-Fe/Co particles with a size and composition (close to Fe(0.50)Co(0.50)) adequate for the increased production of carbon nanotubes. However, larger particles are also produced resulting in the formation of undesirable carbon species. The highest CNT quantity and carbon quality are eventually obtained upon reduction of the iron-free Mg(0.90)Co(0.10)O solid solution, in the absence of clusters of metal ions in the starting material.

Journal Article↗
PubMed2005

Fe/Co alloys for the catalytic chemical vapor deposition synthesis of single- and double-walled carbon nanotubes (CNTs). 2. The CNT-Fe/Co-MgAl2O4 system.

A detailed 57Fe Mössbauer study of the Mg(0.8)Fe(0.2-y)Co(y)Al2O4 (y = 0, 0.05, 0.1, 0.15, 0.2) solid solutions and of the CNT-Fe/Co-MgAl2O4 nanocomposite powders prepared by reduction in H2-CH4 has allowed characterization of the different iron phases involved in the catalytic process of carbon nanotube (CNT) formation and to correlate these results with the carbon and CNT contents. The oxide precursors consist of defective spinels of general formulas (Mg(1-x-y)(2+)Fe(x-3alpha)(2+)Fe(2alpha)(3+)[symbol: see text](alpha)Co(y)(2+)Al2(3+))O4(2-) . The metallic phase in the CNT-Fe/Co-MgAl2O4 nanocomposite powders is mostly in the form of the ferromagnetic alpha-Fe/Co alloy with the desired composition. For high iron initial proportions, the additional formation of Fe3C and gamma-Fe-C is observed while for high cobalt initial proportions, the additional formation of a gamma-Fe/Co-C phase is favored. The higher yield of CNTs is observed for postreaction alpha-Fe(0.50)Co(0.50) catalytic particles, which form no carbide and have a narrow size distribution. Alloying is beneficial for this system with respect to the formation of CNTs.

Journal Article↗
PubMed2005

Prognostic factors and longterm survival after hepatic resection for hepatocellular carcinoma originating from noncirrhotic liver.

BACKGROUND: The incidence of hepatocellular carcinoma (HCC) in cirrhotic and noncirrhotic liver is increasing in the world, probably because of the high prevalence of infections by hepatitis B and C viruses. Despite numerous publications on hepatic resection, prognostic factors for intrahepatic recurrence and survival are not well known for patients with HCC without cirrhosis. STUDY DESIGN: One hundred eight consecutive patients with HCC in noncirrhotic liver have been treated by hepatic resection in the past 18 years in our center. Clinical, biologic, and histopathologic parameters of these patients were collected. Risk factors for intrahepatic recurrence and prognostic factors for survival were evaluated by univariate and multivariate analyses. RESULTS: Postoperative morbidity and mortality rates were 23% and 6.5%, respectively. The 3- and 5-year disease-free and overall survival rates were 55% and 43%, and 43% and 29%, respectively. Blood transfusion, absence of tumor capsule, and daughter nodules were independently associated with overall survival. But the only risk factors for recurrence were blood transfusion, absence of tumor capsule, daughter nodules, and margin resection < 10 mm. CONCLUSIONS: In the treatment of HCC without cirrhosis, hepatectomy remains a safe and legitimate treatment, but longterm results are impaired by a high rate of early recurrence likely related to metastatic dissemination. Only histopathologic factors related to the tumor are predictive of recurrence and overall survival.

Adult↗
PubMed2005

Surgical resection after radiochemotherapy in patients with unresectable adenocarcinoma of the pancreas.

BACKGROUND: The use of chemoradiotherapy for pancreatic cancer has been advocated for its potential ability to downstage locally advanced tumors. This article reports our experience with chemoradiotherapy for patients with unresectable, locally advanced pancreatic cancer (superior mesenteric artery or celiac axis encasement). STUDY DESIGN: Since 1998, 61 patients with radiographically unresectable, pathologically confirmed pancreatic adenocarcinoma have received standard fractionation radiation therapy (total dose, 45 Gy at 1.8 Gy, 5 d/wk) with chemotherapy, which included a continuous infusion of fluorouracil (5-FU: 650 mg/m(2)/D1-D5 and D21-D25) and cisplatin (80 mg/m(2)/bolus D2 and D22). Patients with tumor response at restaging CT scan underwent surgical exploration to determine whether the tumor was resectable. RESULTS: Thirty-eight of 61 (62%) restaged patients demonstrated a disease progression. Twenty-three patients (38%) had an objective response, with, in all cases, persistence of arterial encasement. Twenty-three patients underwent exploratory operations after chemoradiotherapy, and 13 underwent standard Whipple resection. So 13 of 23 (56%) patients who had exploratory operation, or 23 of 61 (21%) patients, underwent surgical resection. With a median followup of 27 months, median survival for the resected patients was 28 months. Median survival was 11 months in the nonresponder group (n = 38) and 20 months in the group who received a palliative procedure (n = 10). CONCLUSIONS: Locally advanced, unresectable pancreatic adenocarcinoma may be downstaged by chemoradiotherapy to allow for surgical resection. Patients whose cancer becomes resectable have a median survival at least comparable with survival after resection for initially resectable pancreatic adenocarcinoma.

Adenocarcinoma↗
PubMed2005

Impact of colloid response on survival after preoperative radiotherapy in locally advanced rectal carcinoma.

Neoadjuvant therapy for rectal carcinoma modifies morphology and natural history of the tumor. Colloid response defined by predominant colloid changes with or without residual tumor cells is a form of tumor response whose impact on survival is unknown. This study evaluated influence of tumor histologic response, especially of colloid response, on survival in patients treated by long-course preoperative radiotherapy for rectal cancer. In 200 patients with uT3-T4 or N1 rectal carcinomas, influence of type of surgery, dose of radiotherapy, residual tumor size, surface tumor aspect, tumor response (downstaging vs. colloid or no response), tumor grade, vascular and neural invasion, circumferential margin, and postoperative chemotherapy on 5-year overall and disease-free survival were studied by univariate and multivariate analyses. A colloid response was observed in 20% of the cases. Tumor response, circumferential margin, and vascular invasion were independently associated with the disease-free survival. Patients with downstaging had a better disease-free survival than patients without response (80% vs. 54%), whereas those with colloid response had an intermediate survival (64%). After colloid response, the rate of recurrence was similar to patients with downstaging for local recurrence (0%-3%) and to those with no response for distant recurrence (28%). After preoperative radiotherapy for rectal cancer, survival and type of recurrence are influenced by the tumor response. The intermediate natural history of patients with colloid response suggests taking colloid response into account in postoperative tumor staging to optimize adjuvant therapy.

Adenocarcinoma, Mucinous↗
PubMed2005

Sphincter-saving resection for all rectal carcinomas: the end of the 2-cm distal rule.

OBJECTIVE: To assess oncologic outcome of patients treated by conservative radical surgery for tumors below 5 cm from the anal verge. SUMMARY BACKGROUND DATA: Standard surgical treatment of low rectal cancer below 5 cm from the anal verge is abdominoperineal resection. METHODS: From 1990 to 2003, patients with a nonfixed rectal carcinoma at 4.5 cm or less from the anal verge and without external sphincter infiltration underwent conservative surgery. Surgery included total mesorectal excision with intersphincteric resection, that is, removal of the internal sphincter, to achieve adequate distal margin. Patients with T3 disease or internal sphincter infiltration received preoperative radiotherapy. RESULTS: Ninety-two patients with a tumor at 3 (range 1.5-4.5) cm from the anal verge underwent conservative surgery. There was no mortality and morbidity was 27%. The rate of complete microscopic resection (R0) was 89%, with 98% negative distal margin and 89% negative circumferential margin. In 58 patients with a follow-up of more than 24 months, the rate of local recurrence was 2% and the 5-year overall and disease-free survival were 81% and 70%, respectively. CONCLUSIONS: The technique of intersphincteric resection permits us to achieve conservative surgery in patients with a tumor close to or in the anal canal without compromising local control and survival. Tumor distance from the anal verge is no longer a limit for sphincter-saving resection.

Adult↗
PubMed2005

Instant electronic patient data input during emergency response in major disaster setting: report on the use of a rugged wearable (handheld) device and the concept of information flow throughout the deployment of the disaster response upon hospital admission.

A hard- and software solution has been conceived, realized, produced and used to gather clinical information about disaster victims in the field in such a way that it makes the different efforts made by mass casualty incident management managers and first responders work more efficient, ergonomic, safe and useful for further scientific and statistic analysis.

Data Collection↗
PubMed2004

Comparison of functional results and quality of life between intersphincteric resection and conventional coloanal anastomosis for low rectal cancer.

PURPOSE: The technique of intersphincteric resection permits sphincter preservation with good oncologic results in very low rectal cancer. This study aimed to investigate functional results and quality of life after intersphincteric resection compared with conventional coloanal anastomoses. METHODS: From 1990 to 2000, 170 patients underwent total mesorectal excision with coloanal anastomosis for low rectal tumors. Questionnaires were obtained from 77 patients alive without colostomy: 37 had a conventional coloanal anastomosis and 40 had intersphincteric resection. Both groups were similar according to age, gender, anastomotic stenosis, colonic pouch, anastomotic leakage, preoperative radiotherapy, and follow-up (median, 56 months). Assessment included one functional and two quality-of-life questionnaires: the SF-36 Health Status and the Fecal Incontinence Quality of Life score. RESULTS: There was no difference in stool frequency, fragmentation, urgency, dyschesia, and alimentary restriction between patients with and without intersphincteric resection. Patients with intersphincteric resection had significantly worse continence (Wexner score, 10.8 vs. 6.9; P < 0.001) and needed more antidiarrheal drugs (60 vs. 35 percent; P = 0.04) than those without. Compared with conventional coloanal anastomoses, quality of life was altered by intersphincteric resection for the subscale embarrassment ( P < 0.01) in the Fecal Incontinence Quality of Life score, whereas no difference of quality of life was observed with SF-36. CONCLUSIONS: Compared with conventional coloanal anastomoses, patients with intersphincteric resection have a higher risk of fecal incontinence and a slightly altered quality of life.

Adult↗
PubMed2004

Impact of microscopic hepatic lymph node involvement on survival after resection of colorectal liver metastasis.

BACKGROUND: Macroscopic hepatic lymph node involvement is usually a contraindication to hepatic resection. Only a few studies have investigated the impact of hepatic lymph node involvement on survival. The aim of this retrospective study was to assess microscopic hepatic lymph node involvement in resectable colorectal liver metastasis and outcomes in patients with such involvement. STUDY DESIGN: From January 1985 to December 2000, 156 patients underwent curative liver resection in association with systematic hepatic lymph node dissection for colorectal liver metastasis. A first analysis was performed to assess the association between hepatic lymph node metastasis and patients' characteristics. A second analysis assessed survival after resection of liver colorectal metastasis by using the Kaplan-Meier method. RESULTS: Twenty-three of the 156 patients (15%) had microscopically involved hepatic lymph nodes. No predictive factor of lymph node metastasis was identified. Multivariate analysis showed that lymph node metastasis, preoperative carcinoembryonic antigen level, number of metastases, and morbidity were factors influencing survival. The 3- and 5-year survival rates of patients with lymph node metastasis were 27% and 5%, respectively, compared with 56% and 43% without lymph node metastasis (p = 0.0001). CONCLUSIONS: During resection of liver colorectal metastasis, microscopic lymph node involvement occurred in 15% of the patients and was associated with a poor 5-year survival. Hepatic lymph node dissection should be performed systematically to select high-risk patients.

Colorectal Neoplasms↗
PubMed2004

Long-term functional results after sphincter-saving resection for rectal cancer.

INTRODUCTION: A number of patients suffer from gastrointestinal side effects following sphincter-saving resection of the rectum. The aim of this study was to assess frequency and risk factors of long-term gastrointestinal side effects after sphincter-saving resection for rectal cancer. PATIENTS AND METHODS: Between 1980 and 1997, among 209 patients treated for rectal cancer by rectal resection and sphincter conservation, 145 who were alive without recurrence or colostomy, responded to a questionnaire. There were 85 males and 60 females with a mean age of 64 Years; the follow-up was 5.4 Years. The functional result was considered good if the number of stools per 24h was three or less with normal continence and poor if the number of stools was four or more or if fecal incontinence was present. Influence of age, gender, anastomotic height, type of sutured colon, colonic pouch, defunctioning stoma, leakage, stenosis, radiotherapy, history of irritable bowel syndrome and follow-up were analyzed. RESULTS: The mean anastomotic height was 5 cm from the anal margin. Functional results were good in 56% of patients and poor in 44%. Univariate analysis showed three variables to be significantly associated with the functional results: anastomotic height (P=0.001), radiotherapy (P=0.03) and follow-up > 24 Months (P=0.009). Multivariate analysis showed that only anastomotic height independently influenced functional results. They were good in 76%, 53% and 35% of patients for anastomoses located above 6 cm, between 6 and 3 cm, and below 3 cm from the anal margin, respectively. CONCLUSION: After sphincter-saving resection for rectal cancer, about half of patients have poor long-term functional results, the latter being related only to the anastomotic height. This suggests the need to preserve a small part of the rectum when oncologically feasible.

Adult↗
PubMed2003

FNH-like nodules: Possible precursor lesions in patients with focal nodular hyperplasia (FNH).

BACKGROUND: The typical lesion of focal nodular hyperplasia (FNH) is a benign tumor-like mass characterized by hepatocytic nodules separated by fibrous bands. The solitary central artery with high flow and the absent portal vein give the lesions their characteristic radiological appearance. The great majority of cases seen in daily practice conform to the above description. Additional small nodules (from 1-2 up to 15-20 mm in diameter) detected by imaging techniques or on macroscopic examination may be difficult to identify as representing FNH if they lack the key features of FNH as defined in larger lesions. The aim of this study was to characterize these small nodules, and to compare their characteristics with those of typical lesions of FNH present in the same specimens. RESULTS: Eight patients underwent hepatic resections for the removal of a mass lesion ("nodule") diagnosed as: FNH (1 patient); nodules of unknown nature (5 patients); or nodules thought to be adenoma or hepatocellular carcinoma (2 patients). Six nodules out of 9 discovered by imaging techniques met histopathological criteria for the diagnosis of typical FNH, at least in parts of the nodule; 2 nodules corresponded to a minor form of FNH ("subtle FNH") and one nodule to a steatotic area. Although FNH was thought to be found in a normal or nearly normal liver, this study revealed that, in addition, there were various types of small FNH-like nodules and vascular abnormalities in the liver with typical FNH nodule. The various types of small FNH-like nodules (n = 8, diameter 2 to 20 mm) consisted of the association to various degrees of numerous and/or enlarged arteries in portal tracts or in septa, with hyperplastic foci, slight ductular reaction, and regions of sinusoidal dilatation, accompanied by thin fibrous bands. Vascular abnormalities consisted of unpaired arteries, portal tracts with arteries larger than the associated bile duct, and regions of sinusoidal dilatation. CONCLUSIONS: Although these small nodules can be considered as insufficient type or abortive forms of FNH, or adenoma, they can be precursors of the large mass lesions in which FNH was recognized and defined.

Journal Article↗
PubMed2003

Gram-scale CCVD synthesis of double-walled carbon nanotubes.

Synthesis of clean double-walled carbon nanotubes by a catalytic chemical vapour deposition (CCVD) method is reported; the catalyst is a Mg(1 - x)Co(x)O solid solution containing additions of Mo oxide; this MgO-based catalyst can be easily removed, leading to gram-scale amounts of clean carbon nanotubes, 77% of which are double-walled carbon nanotubes.

Journal Article↗
PubMed2003

Association of adenoma and focal nodular hyperplasia: experience of a single French academic center.

BACKGROUND: We report our experience of the simultaneous occurrence of adenoma and focal nodular hyperplasia (FNH). Liver cell adenoma together with FNH was found in five out of 30 cases of "multiple benign hepatocytic nodules" collected in our files of the Department of Pathology of the University Hospital of Bordeaux, during the last 12 years. All five cases were women on oral contraceptives. In all cases, the reason for surgery was the discovery, by imaging techniques, of an adenoma (4 cases) or of an unidentified benign tumor, possibly an adenoma. RESULTS: Four cases of FNH were discovered by imaging techniques, prior to surgery. Additional small nodules were diagnosed either during surgery or during the slicing of the specimen in 3 cases. Adenoma and the FNH cases identified by imaging techniques were confirmed as such by light microscopy. Some small nodules could not be categorized with certainty because they contained biliary structures without ductular reaction. In one case, the non-nodular liver was abnormal around the area in which there were multiple nodules: there was approximation of portal tracts with portal and hepatic venous thromboses, and portal tract remnants with arteries surrounded with a rim of fibrosis. In two cases, some large hepatic veins had thickened walls. CONCLUSIONS: The association of FNH and adenoma could be coincidental or secondary to shared causal mechanisms: a) systemic and local angiogenic abnormalities induced by oral contraceptives; b) tumor-induced growth factors; c) thrombosis and local arterio-venous shunting. A better recognition of the association of adenoma and FNH, particularly in the context of multiple nodules, could be useful in clinical practice.

Journal Article↗