Abiud Laurent - Academia.edu (original) (raw)

Papers by Abiud Laurent

IEEE Transactions on Plasma Science, 1991

An inverse method for studying the dynamic behavior of a low-voltage arc column is presented. A s... more An inverse method for studying the dynamic behavior of a low-voltage arc column is presented. A small number of microcoils are placed at suitably chosen points. The measured inductions are recorded during the whole arc life, and the evolution curves of the position of the anodic and cathodic roots, as well as those of the arc column gradient, assumed to

Radiology, 2002

To compare the effects on the myometrium of polyvinyl alcohol (PVA) particles and calibrated micr... more To compare the effects on the myometrium of polyvinyl alcohol (PVA) particles and calibrated microspheres (MS) in embolization of the uterine arteries in sheep. Superselective and bilateral embolization of the uterine arteries was performed with PVA particles and calibrated MS within 24 hours after artificial ovulation in 26 adult nonpregnant sheep. PVA particles of four diameters, 150-250, 250-400, 400-600, and 600-1,000 microm, were compared with calibrated MS of similar diameters, 100-300, 300-500, 500-700, and 700-900 microm, in eight groups of sheep. Evaluation was based on histopathologic study of uterus, ovaries, and vascular pedicles after sacrifice 5 days after embolization. The scores of necrosis, the diameter of occluded arteries, and the number of particles were determined. The scores of uterine necrosis were compared by using nonparametric tests (Mann-Whitney U and Kruskal-Wallis). Spearman rank test was used for correlations. PVA particles clumped more readily than did MS. Small particles had a higher score (P =.02) of uterine necrosis than did large particles. PVA particles produced more necrosis than did MS. Size of MS and diameter of occluded arteries showed significant correlation (rho = 0.762, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.001). Size of PVA particles and diameter of occluded arteries showed no correlation. PVA particles occluded vessels of a wider range of size than did calibrated MS. PVA particles are associated with intense uterine necrosis and extensive arterial occlusion regardless of size. Calibrated MS, which are associated with less uterine necrosis, permit a segmental arterial occlusion correlated with size.

Bioconjugate chemistry, 1997

In the prooligonucleotide approach, a step of activation by cellular esterases is necessary for t... more In the prooligonucleotide approach, a step of activation by cellular esterases is necessary for the removal of internucleoside phosphate masking groups and subsequent intracellular delivery of active antisense oligonucleotides. The efficacy of this approach implies that prooligonucleotides, once they are taken up by cells, are demasked by esterases during their course to their nucleic acid targets. In this regard, a method for labeling oligomers with esterase-activable fluorogenic tag was designed. The two phenolic functions of carboxyfluorescein were protected by pivaloyl groups, yielding a nonfluorescent lactone which was further activated as a N-hydroxysuccinimide ester. Two nuclease-resistant phosphorothioate 18-mer and methylphosphonate 19-mer oligodeoxynucleosides were attached to this biprotected fluorescein derivative via an amino linker at the 5'-end of the oligomers. The two conjugates were assayed for their carboxyesterase substrate ability in different biological media. In the presence of purified esterases or when incubated in serum or cell extracts, both oligonucleotide conjugates became fluorescent. In addition, the phosphorothioate oligoconjugate was microinjected into the cytoplasm of human fibroblasts, and a fast cytoplasmic release of fluorescence was observed with a rapid translocation of the fluorescent oligomer into the nucleus.

Archives of Surgery, 2007

Patients: Fifty patients with benign disease underwent laparoscopic liver resection. Indications ... more Patients: Fifty patients with benign disease underwent laparoscopic liver resection. Indications for resection included preoperative diagnosis of adenoma or cystadenoma, uncertain preoperative diagnosis, and presence of symptoms. Inclusion criteria were lesions 5 cm or less located in the peripheral segments (segments 2-6). Intervention: Laparoscopic liver resection using a surgical technique including 5 ports, harmonic transection, stapling of large vessels, and extraction in a bag through a separate incision. Main Outcome Measures: Intraoperative results and postoperative morbidity. Results: Thirty-five patients (70%) presented with solid tumor; 11 (22%), with cystic lesions; and 4 (8%), with biliary disease. Tumor was solitary in 41 cases (82%) and multiple in 9 (18%). Mean (SD) surgical time was 191 (77.5) minutes (range, 30-480 minutes). There were 4 conversions (8%) and 1 patient received a transfusion (2%). There was no mortality. The postoperative morbidity rate was 10% and included only nonspecific complications. Median hospital stay was 5 days. Conclusions: Laparoscopic liver resection for benign disease can be recommended in patients with peripheral lesions requiring limited resection. Major resections may be performed in highly select patients but require further evaluation. Specific training is required. Indications for laparoscopic resection of benign liver disease must be the same as those for open surgery. Reduction of abdominal wall damage and cosmetic advantages of the laparoscopic approach represent a clear benefit in patients with benign liver disease.

Journal of Molecular Biology, 1972

Single crystals of duck egg-white lysozyme II suitable for high-resolution X-ray diffraction stud... more Single crystals of duck egg-white lysozyme II suitable for high-resolution X-ray diffraction studies were obtained at 4, 20 and 37°C. The space group is P2, and unit-cell dimensions are a = 28.5 A; b = 66.2 A; c = 32 A; ,9 = 113". Suitable heavy-atom derivatives have been prepared. Although only a single type of lysozyme (EC 3.2.1.17) was found in hen, guinea-hen and goose egg-white as well as in normal human tissues or secretions (Jolles, 1969), multiple lysozymes have been characterized in duck egg-white by JollAs, Spotorno & Jolli% (1965). They prepared by ion-exchange chromatography on Amberlite CG50 three fractions, called I, II and III, containing material active against Micrococcw luteus cells. From peaks II and III, histidine-free duck lysozymes were isolated and their primary structures were established (Hermann & Jolles, 1970; Hermann, Jolles & Jolles, 1971). Six replacements were noted between the two duck enzymes; their immunological behaviour (Maron, Arnon, Sela, P&in & Jollb, 1970) as well as their behaviour in the presence of inhibitors (Joll&s et al., 1968) were slightly different. Other groups (Imanishi, Shinka, Miyagawa, Amano UC Tsugita, 1966; Prager & Wilson, 1971) reported also the presence of multiple lysozymes in the duck egg-white and submitted the enzymes to extensive immunological and genetic investigations. Following the studies of Blake, Mair, North, Phillips & Sarina (1967) on hen and of Blake t Swan (1971) on human leukaemio lysozymes, we decided to establish the tertiary structure of the two hi&line-free duck lysozymes II and III; they differed from hen by 19 and 20 and from human lysozymes by 48 and 47 residues, respectively (Jolles, van Leemputten, Mouton & Jo&s, 1972). The present note deals w&h the crystallization and some preliminary X-ray data of duck lysozyme II. Despite the fact that enzymes II and III were nearly-related substances, our efforts to crystallize duck lysozyme III have remained unsuccessful until now. Duck egg-white lysozyme II was prepared and purified according to Hermann et al. (1971). The crystallization was achieved at 4, 20 and 37'C. To 6 mg enzyme dissolved in O-27 ml. water was added O-03 ml. of O-2 M-phosphate buffer, pH 5-26; after centrifugation, O-3 ml. of 3 M-ammonium nitrate was added and the pH was adjusted to 8. Under these experimental conditions, suitable crystals (3 mm x 1 mm x 1 mm) were obtained in a few days (Plate I). Smaller orystals could be obtained by other procedures, namely in a O-02 M-T& buffer, pH 8, and 16% N&Cl. The crystals obtained at 37°C could be stored for weeks at 20°C without deterioration (Jolles & Berthou, 1972). For all crystallization techniques the crystals were monoclinio and were usually bounded by well-developed 010 iO0 iO1 forms. The space group was P2, and unitcell dimensions were a = 28-5 8; b = 66-2 A; c = 32 A; p = 113'. Their lifetime in the X-ray beam was at least 3 days. The water content was measured by thermo-'Ibis investigation was supported in part by the C.N.R.S. (ER102), I.N.S.E.R.M. (groupe U116) and HofTmann-La Roche, I&ale.

Investigative …, 1994

RATIONALE AND OBJECTIVES: The feasibility of tubal occlusion by selective salpingography was test... more RATIONALE AND OBJECTIVES: The feasibility of tubal occlusion by selective salpingography was tested in an animal model; three novel occluding materials also were tested for this application. METHODS: Unilateral selective salpingography was performed ...

Malaria …, 2010

The overall malaria prevalence was 34.3% according to microscopy and 57.2% according to the HRP-2... more The overall malaria prevalence was 34.3% according to microscopy and 57.2% according to the HRP-2 test. The HRP-2 test had a sensitivity of 96.1%, a specificity of 63.1%, a positive predictive value of 57.6% and a negative predictive value of 96.9%. The test sensitivity was higher ( ...

Annals of Surgical Oncology, 2008

Background: This study characterizes the histological effect of chemotherapy (CT) on primary colo... more Background: This study characterizes the histological effect of chemotherapy (CT) on primary colonic tumors. Methods: Between 2000 and 2006, 38 patients with stage IV colon cancer underwent resection of the primary, after chemotherapy (CT group, n = 16) or without preoperative CT (control group, n = 22). For all primary tumors, histological analysis included: fibrosis, acellular necrosis, acellular mucin pools, lymphoplasmacytic infiltration, and changes at tumor surface. Tumor regression grade (TRG) was determined by the amount of residual tumor cells and was graded from 1 to 5. Results: No patient had complete histological response. Major histological tumor regression (TRG2) was observed in 70% of patients treated by CT and none of the not treated patients (P < 0.0001). Fibrosis, acellular necrosis, and surface changes were significantly increased in the CT group. TRG in the primary was comparable to the TRG in the corresponding liver metastases for 7/9 patients who underwent both colonic and hepatic resection after CT. Conclusion: CT induces major histological response in 70% of colon cancers. Response to CT in the primary and the corresponding liver metastases are correlated. These results support a policy of initial CT management for stage IV colon cancer and may warrant future studies of neoadjuvant CT in locally advanced colon carcinomas.

Acoustics, Speech …, 2009

Industrial & engineering …, 1994

... Res. 1994,33, 519-525 519 Influence of Gas Density on the Hydrodynamics of Cocurrent Gas-Liqu... more ... Res. 1994,33, 519-525 519 Influence of Gas Density on the Hydrodynamics of Cocurrent Gas-Liquid Upflow F,ixed Bed Reactors Faiqal Larachi,&#x27;.+ Gabriel Wild$, Andre Laurentt, andNoel Midouxt ... G = 0.86 kg . m&quot;. 1.l L I 12.8 kg . m.&#x27;. d 4 n 0.05 10 20 30 Time 40 Fimre2. ...

Science of The Total Environment, 1982

ABSTRACT The EUROPOLL multicell scrubber is a new gas-liquid contactor that may be use for the fi... more ABSTRACT The EUROPOLL multicell scrubber is a new gas-liquid contactor that may be use for the fight against the chemical and dust pollution of air.This contactor involves a regular package of elementary patterns called cells in which it is possible to transfer mass and/or heat between the gas and liquid phases. Indeed each cell comprises a convergent and a divergent the intersection of which constitutes the throat and thus leads to a good contact between the phases.From the hydrodynamic point of view, the scrubber is characterized by graphs of pressure losses and liquid holdup and by the domain of the flowrates leading to the working in satisfactory conditions.The capacity of the mass transfer of the contactor is presented in terms of liquid side and gas side mass transfer coefficients and of gas-liquid interfacial area.Finally the performances of the scrubber are compared with those of the other classical contactors employed to fight the air pollution. This is made with the use of a diagram plotting the mass transfer parameters versus the spent energy.

Journal of the …, 1985

The density of myelinated fibres in the superficial peroneal nerve was studied in 41 samples from... more The density of myelinated fibres in the superficial peroneal nerve was studied in 41 samples from 24 control human subjects. Photographic montages of the whole nerve fascicle were made from semithin and ultrathin transverse sections and used for a statistical analysis of sampling procedures, range of variations and relations between density and other variables. The results indicate that the spatial distribution of myelinated fibres within a nerve is often non-uniform. Therefore, it was not possible to define a statistically valid sampling system. The study of relations between variables shows the lack of any correlation between density and age and a considerable variation in the density. In contrast, there is a strong positive linear correlation between the surface area of the nerve fascicle and its content of myelinated fibres. That is, the fibre density of a given normal nerve is related to its diameter and can be predicted within a narrow range of error. We propose the term "derived density" for this value, and its application as a tool in the diagnosis of peripheral neuropathies is now being studied.

Research in …, 1992

In vitro transmission and antigenicity of a retrovirus isolated from a multiple sclerosis patient... more In vitro transmission and antigenicity of a retrovirus isolated from a multiple sclerosis patient H. Perron (1)(2)(.), B. Gratacap (2), B. Lalande (2), O. Genoulaz (2), A. Laurent (3), C. Geny (6), M. Mallaret (4) p. Innocenti (2), E. Schuller (5), p. Stoebner 0) and J.M. Seigneurin (2)