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Biomedical subjects

Y Le Roux

Publications and source records attributed to Y Le Roux.

At least 19 recordsLinked to original sources
PubMed2005

Study of mammary epithelial role in polycyclic aromatic hydrocarbons transfer to milk.

Food would appear to be one of the main routes for animal and human contamination with polycyclic aromatic hydrocarbons (PAH). Many studies have shown the presence of PAH in milk and dairy products, suggesting that these foods can represent a part of this contamination. Our work aimed at defining, in vitro, the mammary barrier role in PAH transfer to milk. MAC T cells were cultivated on permeable filters to measure transepithelial permeability of 14C labeled benzo[a]pyrene (BaP), pyrene (Pyr), and phenanthrene (Phen), which differed in their physicochemical properties. The results showed that only 2 molecules, Phen and Pyr, were able to cross mammary cell layers. Phenanthrene radioactivity appeared more quickly in apical media, and its level after a 6-h exposure was 1.3 times higher than for Pyr and 7.7 times higher than for BaP. These findings suggested that mammary epithelium could play a key role in the selective transfer of PAH from food to milk.

Animals↗
PubMed2004

Thoracoscopic plication of the diaphragm for postoperative phrenic paralysis: a report of two cases.

Unilateral phrenic nerve paralysis after cardiothoracic surgery is not uncommon. When symptomatic, it can require surgical treatment. Plication of the diaphragm through a thoracotomy is known to provide excellent long-term results. Plication is now being performed via video-assisted thoracoscopic surgery (VATS). We report the cases of two patients with postoperative left phrenic nerve paralysis who underwent plication of the diaphragm using VATS and achieved total relief of all symptoms.

Diaphragm↗
PubMed2004

Proteolysis in milk during experimental Escherichia coli mastitis.

This work consisted of the intramammary infections (IMI) of 8 heifers by high doses of Escherichia coli to study both the proteolytic activity in milk and the resulting peptides. Therefore, a milking kinetic has been followed, and several parameters have been studied, such as proteose peptones (PP) fraction (quantitative and qualitative changes), plasmin activity (PA), milk somatic cell count (SCC), and bacterial count. A qualitative study of milk proteins and PP was performed by sodium dodecyl sulfate-PAGE, and the peptides recovered in PP during the acute phase of inflammation were amino-terminal micro-sequenced. A BSA increase in milk over time supported the hypothesis of an increase in the permeability of the epithelial barrier. A significant increase in PP content, considered to be an indicator of proteolysis, was observed from postinfusion hours (PIH) 12 to 48. Both the E. coli bacterial count and the SCC increased from PIH 3 to 216. Plasmin activity was increased noticeably from PIH 15 to 24. The respective increases in SCC, bacterial count, and PA suggest their involvement in a global mechanism responsible for the increase in proteolysis in milk after E. coli challenge. Somatic cell count and E. coli may be involved from PIH 3 to 216, and PA involvement might be highlighted during the maximum proteolysis, from PIH 15 to 24. A qualitative study of PP fraction by electrophoresis revealed the apparition of 5 peptide bands: P1 and P2 previously recovered during the lipopolysaccharide challenge, and E1 (27.0 kDa), E2 (15.5 kDa), and E3 (9.0 kDa) were specific to E. coli challenge; E1, E2, and E3 contained casein fragments. The roles played by leukocytes and E. coli are discussed.

Animals↗
PubMed2004

Isolation and characterization of copolymers of beta-lactoglobulin, alpha-lactalbumin, kappa-casein, and alphas1-casein generated by pressurization and thermal treatment of raw milk.

Raw skim milk was submitted to high pressure (300 to 600 MPa) and temperature (4 to 70 degrees C) treatments for 2 or 5 min. The combined effects of pressure and temperature on milk proteins induced structural changes and polymer and copolymer formation characterized by anion-exchange and size-exclusion fast protein liquid chromatography and electrophoretic techniques. Approximately half of the beta-lactoglobulin formed polymers, and the other half formed large copolymers, mainly with kappa-casein, alpha-lactalbumin via intermolecular disulfide bond exchange, and alpha(s1)-casein via physicochemical interactions, in proportions of 1.0:0.7:0.3:0.1, respectively. Minor whey proteins (serum albumin, immunoglobulins, and lactoferrin) also participated in the formation of the copolymers but to a lesser extent. Two populations of the copolymers were found with apparent molecular masses ranging from 440 to 2000 kDa for the first and more than 2000 kDa for the second. On the contrary, for heated milks the aggregation kinetics obtained by combination of high pressure and thermal treatment were very fast, as no intermediates such as dimers and small size oligomers were observed after pressurization, whatever the temperature studied. Lactosylation of proteins as well as proteolysis were very limited. A beta-casein amino-terminal peptide of 22 kDa was specifically recovered in milk samples treated under the more drastic conditions (500 MPa/55 degrees C per 5 min and 600 MPa/70 degrees C per 5 min) and might have been generated by neutral proteases such as elastase released from somatic cells present in milk. No casein was released from the micelle whatever the combination of high pressure and temperature studied.

Amino Acid Sequence↗
PubMed2003

Contamination of pastures by polycyclic aromatic hydrocarbons (PAHs) in the vicinity of a highway.

To assess PAH contamination pastures, grass and soil samples have been collected from 10 m (d1), 50 m (d2), and 150 m (d3) perpendicular to a French highway (70,000 vehicles per day) and at a control site in a rural area away from nearby contaminating sources. Total PAH concentration ranges from 767 ng/g dry weight to 3989 ng/g dry weight, according to the matrix and the distance from the highway. Distance is not a significant factor for PAH deposition on grass, while in soil it has an effect between d1 and d2 or d3. The total PAH concentration in highway samples is 8 times higher than in control site samples for grass and 7 to 4 times higher for soil. Fluoranthene, pyrene, and phenanthrene are the major PAHs in grass samples at the control site and the highway, but the concentrations are about 5 times higher near the highway. In soil samples collected near the highway, the values of concentrations between all compounds are not statistically different. PAH deposition on grass is linked to the physicochemical properties of the compounds, which lead to a specific distribution of each molecule (according to their volatility and the number of aromatic rings) while no specific behavior is revealed in soil.

Agriculture↗
PubMed2003

Characterization and proteolytic origins of specific peptides appearing during lipopolysaccharide experimental mastitis.

Based on the compositional change of the proteose peptone fraction, proteolysis was studied over time following lipopolysaccharide-induced experimental mastitis. Electrophoresis of the proteose peptone fraction revealed many degradation products. Five peptides were identified by amino-terminal sequencing as internal fragments of beta-, kappa-, alpha(s1)-, and alpha(s2)-casein that were generated by somatic cell proteases. Although kappa-casein is considered particularly resistant to endogenous proteolysis, a kappa-casein peptide was electrophoretically isolated in association with a beta-casein fragment. The in vitro kinetic studies of caseinate hydrolysis by elastase, one of the main polymorphonuclear neutrophil (PMN) proteases, suggested that the beta-casein peptide might be generated by elastase. In addition, elastase activity in milk PMN was higher during the inflammation of the mammary gland than prior to infusion.

Amino Acid Sequence↗
PubMed2002

Enzymatic activities of bovine peripheral blood leukocytes and milk polymorphonuclear neutrophils during intramammary inflammation caused by lipopolysaccharide.

Leukocytes are recruited from peripheral blood into milk as part of the inflammatory response to mastitis. However, excessive accumulation of inflammatory cells alters the quality of milk and the proteases produced by polymorphonuclear neutrophils (PMNs) and macrophages may lead to mammary tissue damage. To investigate PMN recruitment and the kinetics of their intracytoplasmic enzymes in inflammation, we generated mastitis in six cows by intramammary infusion of lipopolysaccharide (LPS). Clinical signs of acute mastitis were observed in all of the cows, and normal status was resumed by 316 h. Intracytoplasmic elastase, collagenase, and cathepsin activities were measured within live cells by flow cytometry in peripheral blood leukocytes and milk PMNs before and during the inflammatory process (at 10 time points between 4 and 316 h). The proportion of immature PMNs was appreciated by CD33 surface labeling measured in flow cytometry. Leukopenia was observed in the peripheral blood 4 h postinfusion, concomitant to an increase in somatic cell counts in milk. CD33(+) PMNs were preferentially recruited from the peripheral blood to milk. Enzymatic activities were detected in PMNs, lymphocytes, and monocytes at levels depending on the cell type, sample nature, and time of collection. Milk PMNs had lower enzymatic activities than peripheral blood PMNs. This study showed that milk PMNs recruited during LPS-induced experimental mastitis have an immature phenotype and significantly lower enzymatic activities than peripheral blood PMNs. This suggests that CD33, an adhesion molecule, may be involved in the egress from blood to milk and that the enzymatic contents of PMNs are partly used during this process.

Animals↗
PubMed2002

Mechanisms involved in milk endogenous proteolysis induced by a lipopolysaccharide experimental mastitis.

Experimental mastitis has been induced by the lipopolysaccharide (LPS) of Escherichia coli on six dairy cows in order to study the mechanisms involved in milk endogenous proteolysis during the inflammatory process. Variations in somatic cell count (SCC), plasmin activity, and total casein (CN) content were measured, and proteose-peptone content and the percentage of pH 4.6 insoluble peptides including gamma-CN have been considered as indicators of endogenous proteolysis. Furthermore, polymorphonuclear neutrophils (PMN) maturity has been evaluated by optical microscopy, and proteolysis by PMN proteinases has been studied at neutral and acidic pH in order to establish a link between caseinolysis, proteinase class, and PMN maturation. Two peaks of proteose-peptones content have been noticed for the six cows. First peak could be explained by both plasmin activity and SCC, while second peak was concomitant with a low plasmin activity but a SCC remaining high. The second peak of proteose-peptones content confirmed the role of cellular proteases in milk caseinolysis. Casein breakdown by cellular proteases was confirmed by SDS-PAGE electrophoresis, and a link between neutral proteinases activity and immature PMN recruitment was shown. Acidic proteinases activity was effective with mature PMN and during the recovery phase.

Animals↗
PubMed2000

[Statistical analysis in the evaluation of controlled diffusion of iodine in the water in developing countries].

This report describes the methodology and findings of a novel statistical technique for evaluation of the efficacy of the Rhodifuse Iode system in prevention of endemic goiter in Mali. The system involves continuous release of iodine in ground water used for drinking. Study was carried out in four villages for one year. The iodine release system was used in three villages. The fourth village served as the control. The incidence of goiter graded using the criteria of the WHO was assessed in each village according to sex. Statistical analysis consisted of correlating goiter grade with four predictors, i.e., village, sex, iodine release, and time. Since goiter grade is a dependent variable, its law of probability was modeled in function of the predictors. The Cat Mot procedure included in the SAS software package allowed both definition of the law of probability of grade of goiter and its transformation in function of predictor. The generalized linear model was obtained by either the generalized least square method or greatest likelihood method. The Proc Catmod procedure was then used to generalize analysis of variance in case of a nominal or ordinal, binary or polytomic response. The results of this novel statistical technique suggested that the Rhodifuse Iode system was effective.

Adult↗
PubMed1999

[Laparoscopic treatment of common bile duct lithiasis. Study of 56 cases].

AIM OF THE STUDY: The aim of this retrospective study was to report the results of the laparoscopic management of common bile duct stones in an unicentric series of 56 patients. PATIENTS AND METHOD: From January 1993 to April 1998, 56 patients, 38 women, 18 men (mean age: 59.2 years), underwent a common bile duct exploration for lithiasis through a laparoscopic approach. The patients were hospitalised for angiocholitis (n = 13), cholecystitis (n = 11), biliary pain (n = 29, nine with jaundice), pancreatitis (n = 3), abnormality of hepatic profile (n = 1). All the patients underwent an intraoperative cholangiography. Removal of the stones was tried in 50 cases through a choledochotomy, in four through the cystic duct, using Mirrizi forceps, or Dormia and Fogarty catheters in case of failure. External biliary drainage and postoperative cholangiography were done systematically. The average diameter of the common bile duct was 10.5 mm (6-20 mm). RESULTS: In 41 patients, removal of the stones was laparoscopically successful. In 11 patients, a conversion into laparotomy was necessary for several reasons. In three patients with common bile duct of small diameter, the stones were abandoned for a further endoscopic sphincterotomy. There was no mortality and the morbidity rate was 7%. The mean postoperative hospital stay was 8.6 days (4-20) for all the series and 7.8 days in case of successful laparoscopic management. CONCLUSION: In 73% of the patients, the treatment of the common bile duct lithiasis could be achieved laparoscopically, but conventional approach and endoscopic sphincterotomy are still useful in case of failure of the laparoscopic management.

Adult↗
PubMed1999

[Long-term results of the treatment of eventrations by intraperitoneal non-absorbable prosthesis (149 patients)].

The authors report a series of 149 cases of incisional hernia, operated between 1983 and 1993, by insertion of a non-absorbable prosthetic mesh within the intraperitoneal cavity. This series consisted of 93 women and 56 men, with a mean age 57 years. One third of repairs were performed because of primary treatment failure. One or more operative risk factors were present in 127 patients. A non-absorbable intraperitoneal prosthetic mesh was inserted with tension to allow good musculo-aponeurotic repair. Postoperative mortality was 0.6%. All but 13 of the patients, were reviewed with a mean follow-up of 83 months. Twenty eight patients (20%) developed recurrence. In 8 cases, the cause of recurrence was failure of prosthetic mesh insertion because of excessive tension. Three patients (1.7%) developed a fistula in contact with the prosthetic mesh, that had to be removed. A small bowel fistula was observed in 2 cases after an intraoperative wound in 1 case, and a colonic fistula in 1 case. The results of incisional hernia repair with nonabsorbable intraperitoneal prosthetic mesh can be compared with these of other techniques using prosthetic materials. This technique does not require dissection of the intermediate planes and avoids undermining which causes substantial bleeding. The risk of sepsis is also decreased by deep placement of the prosthesis. The exceptional cases of fistula or the possibility of migration of the prosthesis are not exclusively observed with this technique, but must clearly encourage a very strict aseptic technique, with placement of omentum between the prosthetic mesh and the viscera.

Adult↗
PubMed1998

Laparoscopic anatomical hepatic resection. Report of four left lobectomies for solid tumors.

Four patients underwent a laparoscopic left hepatic resection for solid tumor, two for metastasis from colonic cancer, and two for focal nodular hyperplasia (final diagnosis). The procedure was performed according to the rules of conventional hepatic surgery and cancer surgery. No blood transfusion was necessary. No surgical complication occurred. In malignant disease, laparoscopy allows a good staging and the performance of a real no-touch technique; the specimen is removed in a plastic bag without contact to the abdominal wall. In symptomatic benign disease the esthetic benefit of the laparoscopic approach is real. In asymptomatic benign disease, laparoscopy could allow large biopsies in the case of uncertain diagnosis or dangerous resection. It allows safe resections in the case of small, well-located tumors. This approach requires sophisticated material and extensive experience in both laparoscopy and hepatobiliary surgery.

Adult↗
PubMed1998

[Medico-economic evaluation of treatment of inguinal hernia: Shouldice vs. laparoscopy].

Between May 1994 and September 1995, 64 men were included in a randomized prospective study comparing conventional Shouldice repair (S group) and transperitoneal laparoscopic repair with polypropylene mesh (L group). Cost evaluation was divided into distinct parts: drugs, non usable surgical materials, medico-technical procedures food and employees costs. In group S, mean operating time was 56', total cost was 3,922 FF in the case of unilateral hernia and 4,808 FF and respectively 77' in the case of bilateral hernia. In group L, mean operative time was 89', total cost 8,949 FF (disposable trocars) and 7,136 FF (non-disposable trocars) in the case of unilateral hernia and 116', 9,570 FF and 7,763 FF in case of bilateral hernia. Postoperative stay was 4.2 days in group S and 4 days in group L. Return to work was 28.6 days in group L and 35.5 days in group S (ns). In conclusion laparoscopic hernia repair does not decrease post operative pain, hospital stay and return to work, but is twice as expensive.

Adult↗
PubMed1997

Single- and multiple-dose pharmacokinetics of riluzole in white subjects.

Riluzole is a novel neuroprotective agent that has been developed for the treatment of amyotrophic lateral sclerosis. A series of studies was undertaken to establish its pharmacokinetics on single- and multiple-dose administration in young white male volunteers. The mean absolute oral bioavailability of riluzole (50-mg tablet) was approximately 60%. Maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) values were linearly related to dose for the range studied. Cmax occurred at 1.0 hour to 1.5 hours after administration. Plasma elimination half-life appeared to be independent of dose. After repeated administration of 100 mg riluzole for 10 days, some intraindividual variability in bioavailability was seen. A high-fat meal significantly reduced the rate (tmax = 2 hours compared with 0.8 hours; Cmax = 216 ng.mL-1 compared to 387 ng.mL-1) and extent of absorption (AUC = 1,047 ng.hr.mL-1 versus 1,269 ng.hr.mL-1). With multiple-dose administration, riluzole showed dose-related absorption, although the terminal plasma half-life was prolonged slightly. Steady-state plasma concentrations were achieved within 5 days. Steady-state trough plasma concentrations were significantly higher with a 75-mg dose twice daily than with a 50-mg dose three times daily, although AUC values did not differ.

Adolescent↗
PubMed1997

[Contribution of laparoscopy in the management of abdominal stab wounds].

Laparotomy is useless in 5 to 39% of patients suffering from penetrating abdominal trauma. The objective of this study is to try to determine the value of laparoscopy in the management of such patients. Thirteen patients underwent laparoscopy for abdominal wound. 11 of these patients had a penetrating abdominal trauma and only 4 of them suffered from lesions requiring surgical treatment (2 intestinal wounds, 1 gastric wound and 1 coeliac artery disruption). No treatment was required in 30 cases (1 wound of intestinal serosa and 2 superficial hepatic wounds). In the last 6 cases no intra-abdominal wound was found. There was no mortality or morbidity. No lesions were missed at laparoscopy. Laparoscopy avoided useless laparotomy in 9 out of 13 patients. This suggests that laparoscopy is a reliable method in the management of patients suffering from abdominal wounds, allowing a very sensitive and specific diagnosis of penetration and visceral injuries. In some cases, is allows laparoscopic treatment of the visceral injury.

Abdominal Injuries↗
PubMed1996

[Geotropic reaction of different types of roots in Hevea brasiliensis].

To describe the different types of geotropic reactions of hevea (Hevea brasiliensis), young seedlings were cultivated in root observation boxes and submitted to a double gravistimulation (90 degrees rotation of the minirhizotrons in the vertical plane). It was demonstrated that the taproot is a strongly orthogeotropic organ since it resumed rapidly its prestimulation vertical position. Morphological and morphogenetic modifications were associated with the geotropic response: reduced speed of growth coupled with a reduction of the apical diameter as well as an alteration of ramification density in the curving zone and the following one. Early secondary roots showed a somewhat reduced orthogeotropism that was weaker as the growth direction before gravistimulation was more distant from the vertical. Secondary roots of the acropetal sequence were semiplagiotropic, that is only those roots oriented upward after the gravistimulation resumed, more or less, the original direction. Tertiary roots didn't respond to the gravistimulation and therefore were ageotropic. Complementary observations conducted in large laboratory rhizotrons showed that late forming secondary roots were plagiotropic in their younger stages, thereafter loosing most of their sensitivity to gravity. Quaternary roots were ageotropic. On the basis of these data, a geotropic gradient was defined within the hevea root system, where the strongly responding taproot and late secondary roots are opposed to the weakly or nonresponding tertiary and quaternary roots. Functional significations of the differential geotropic reactions in different hevea root types are discussed.

Gravitation↗