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Biomedical subjects

P Guiraud

Publications and source records attributed to P Guiraud.

At least 19 recordsLinked to original sources
PubMed2005

Assessment of anthracene toxicity toward environmental eukaryotic microorganisms: Tetrahymena pyriformis and selected micromycetes.

The toxicity of anthracene, a nonmutagenic, noncarcinogenic, low-molecular-weight polycyclic aromatic hydrocarbon present in the environment, was assessed using a ciliated protozoan, Tetrahymena pyriformis, and a selection of 10 micromycetes from different taxonomic groups living in two environmental compartments, namely aquatic and soil ecosystems. With T. pyriformis, a concentration-dependent inhibitory effect was shown on the cell proliferation rate, IC(50) = 33.40+/-4.84 mg/L (kinetic method). Phagocytosis of nonsoluble anthracene was confirmed by the presence of digestive vacuoles with photon microscopy. In fungi, anthracene did not exhibit a fungicide effect but showed a fungistatic action. Except for Absidia fusca and Cladosporium herbarum, the micromycetes showed a concentration-dependent decrease in growth. From IC(50) values determined by endpoint or kinetic methods, Rhodotorula glutinis and all of the Ascomycotina (except for Penicillium chrysogenum) were the most sensitive species, while Phanerochaete chrysosporium, P. chrysogenum, and the two Deuteromycotina were more resistant to anthracene. Our discussion focuses on the evaluation of toxicity by the two methods used for the calculation of the IC(50) values (endpoint and kinetic), the advantages of studying growth by a kinetic method (the dynamic aspect), and a comparison of toxicity to T. pyriformis and the different micromycetes.

Animals↗
PubMed2003

Biodegradation capability of Absidia fusca Linnemann towards environmental pollutants.

The purpose of this work was to study the bioremediation capability of Absidia fusca Linnemann (Zygomycete) towards different classes of xenobiotics (lignin-derived compounds, chloroaromatic compounds, polycyclic aromatic hydrocarbons) the presence of which in contaminated soils, water and sediments poses a significant risk to the environment and human health. Two strains from different origins were compared. One was from an official collection and grown in non-inducing conditions, while the other was isolated during the course of the survey of fungal flora in a polluted soil from Annaba (Algeria). All data were analyzed and results validated via a statistical treatment. We showed the effect of the factors studied (origin of the strain, xenobiotic) but also the interactions between these factors. The strain of A. fusca isolated from a polluted soil was able to efficiently degrade most of the xenobiotics tested, particularly: pentachlorophenol, phenol, catechol, guaiacol and ferulic acid. This property also existed in the other strain but at a very low level.

Absidia↗
PubMed2001

Human immunodeficiency virus type 1 Tat protein impairs selenoglutathione peroxidase expression and activity by a mechanism independent of cellular selenium uptake: consequences on cellular resistance to UV-A radiation.

The expression of the HIV-1 Tat protein in HeLa cells resulted in a 2.5-fold decrease in the activity of the antioxidant enzyme glutathione peroxidase (GPX). This decrease seemed not to be due to a disturbance in selenium (Se) uptake. Indeed, the intracellular level of Se was similar in parental and tat-transfected cells. A Se enrichment of the medium did not lead to an identical GPX activity in both cell lines, suggesting a disturbance in Se utilization. Total intracellular 75Se selenoproteins were analyzed. Several quantitative differences were observed between parental and tat-transfected cells. Mainly, cytoplasmic glutathione peroxidase and a 15-kDa selenoprotein were decreased in HeLa-tat cells, while phospholipid hydroperoxide glutathione peroxidase and low-molecular-mass selenocompounds were increased. Thioredoxin reductase activity and total levels of 75Se-labeled proteins were not different between the two cell types. The effect of Tat on GPX mRNA levels was also analyzed. Northern blots revealed a threefold decrease in the GPX/glyceraldehyde phosphate dehydrogenase mRNA ratio in HeLa-tat versus wild type cells. By deregulating the intracellular oxidant/antioxidant balance, the Tat protein amplified UV sensitivity. The LD50 for ultraviolet radiation A was 90 J/cm2 for HeLa cells and only 65 J/cm2 for HeLa-tat cells. The oxidative stress occurring in the Tat-expressing cells and demonstrated by the diminished ratio of reduced glutathione/oxidized glutathione was not correlated with the intracellular metal content. Cellular iron and copper levels were significantly decreased in HeLa-tat cells. All these disturbances, as well as the previously described decrease in Mn superoxide dismutase activity, are part of the viral strategy to modify the redox potential of cells and may have important consequences for patients.

Copper↗
PubMed2001

Biodegradation of anthracene and fluoranthene by fungi isolated from an experimental constructed wetland for wastewater treatment.

Pilot-scale constructed wetlands were used to treat water contaminated by polycyclic aromatic hydrocarbons (PAHs), particularly fluoranthene, and the possible role of fungi present in these ecosystems was investigated. A total of 40 fungal species (24 genera) were isolated and identified from samples (gravel and sediments) from a contaminated wetland and a control wetland. All of them were assayed for their ability to remove anthracene (AC) and fluoranthene (FA) from liquid medium. FA was degraded efficiently by 33 species while only 2 species were able to remove AC over 70%. A selection of 10 strains of micromycetes belonging to various taxonomic groups was further investigated for FA and AC degradation, toxicity assays and phenoloxidases (POx) detection. Interesting and not previously reported species were revealed (Absidia cylindrospora, Cladosporium sphaerospermum, and Ulocladium chartarum). They were all able to highly degrade the PAH-model compounds chosen. An interesting inducibility was noted for Ulocladium chartarum. Degradative ability of fungi was not related to their extracellular POx activity. This study may contribute to the improvement of constructed wetlands for water treatment, which may be enriched in efficient fungi.

Anthracenes↗
PubMed2001

Early endoscopic realignment of post-traumatic posterior urethral disruption.

OBJECTIVES: The management of complete or partial urethral disruption is controversial, and much debate continues regarding immediate versus delayed definitive therapy. We further analyze our experience and long-term results using early endoscopic realignment. METHODS: Between April 1987 and January 1999, 29 men with posterior urethral disruption (23 complete and 6 partial) underwent primary urethral realignment 0 to 8 days after injury. Pelvic fractures were present in 23 patients. In all patients, the actual operating time for realignment was 75 minutes or less. All patients were evaluated postoperatively for incontinence, impotence, and strictures. RESULTS: After a mean follow-up of 68 months (range 18 to 155), all patients were continent. Four patients (13.7%) required conversion to an open perineal urethroplasty. At the last follow-up visit, 25 (86%) of the 29 patients were potent and 4 achieved adequate erections for intercourse using intracorporeal injections (prostaglandin E(1)). Twelve patients (41%) developed short secondary strictures and were successfully treated with internal urethrotomy. The mean follow-up of these 12 patients was 83 months (range 34 to 120). Urinary flow rate measurement at the last follow-up visit revealed satisfactory voiding parameters in all patients. CONCLUSIONS: Primary endoscopic realignment offers an effective method for treating traumatic urethral injuries. Our long-term follow-up provides additional support for the use of this technique by demonstrating that urethral continuity can be established without an increased incidence of impotence, stricture formation, or incontinence. In case of failure, endoscopic realignment does not compromise the result of secondary urethroplasty.

Adolescent↗
PubMed2001

A conservative approach to major blunt renal lacerations with urinary extravasation and devitalized renal segments.

OBJECTIVES: To determine the feasibility of a conservative (expectant) approach to major blunt renal laceration with urinary extravasation and devitalized renal segments. PATIENTS AND METHODS: All patients treated conservatively who presented between 1990 and 1999 with major renal laceration (grade 4 and 5) were retrospectively reviewed to determine whether urinary extravasation and devitalized segments adversely affected the outcome. For each patient the data collected included the initial emergency department evaluation, findings on computed tomography, associated injuries, duration of hospital stay, transfusion requirements, complications and follow-up imaging. RESULTS: Of 20 patients who sustained blunt trauma resulting in a major renal laceration (five grade 5 and 15 grade 4) with urinary extravasation, 11 had coexisting devitalized segments. There was a statistically significant difference in the length of hospital stay (16.3 vs 7.3 days), blood transfusions (six vs two patients, P < 0.08) and the need for delayed surgical intervention (nine vs two, P < 0.01) between patients with and with no devitalized segments, respectively. Urinary extravasation spontaneously resolved in two of 11 patients with and in seven of nine with no devitalized segment, respectively (P < 0.05) CONCLUSIONS: Urinary extravasation will resolve spontaneously in most patients with blunt renal trauma, and expectant treatment does not adversely affect the outcome or prolong hospitalization. In patients who present with a major renal laceration associated with devascularized segments, conservative management is feasible in those who are clinically stable with blunt trauma. However, the physician must be especially aware of the probable complications within this subset of patients.

Adolescent↗
PubMed2001

Recurrent pyelonephritis without vesicoureteral reflux: is there a role for an antireflux procedure?

PURPOSE: To evaluate the results of an endoscopic antireflux procedure in women with recurrent acute pyelonephritis and no evidence of vesicoureteral reflux (VUR) on voiding cystograms. PATIENTS AND METHODS: From 1989 to 1999, 603 female patients were hospitalized for acute pyelonephritis with unilateral loin pain, chills, fever, and a positive urine culture. Of these patients, 48 (8%) had recurrent episodes of acute pyelonephritis and underwent a thorough diagnostic work-up including intravenous urography or renal CT scan, cystoscopy, and voiding cystourethrography (VCUG). Vesicoureteral reflux was demonstrated in 21 patients, who were then offered an antireflux procedure, either surgical or endoscopic. Another 27 patients had no reflux on VCUG; in 15 cases, the upper urinary tract was normal, and the ureteral orifices did not show any abnormality on cystoscopy. The other 12 patients in this group with a normal VCUG had one or more abnormal findings normally associated with VUR: renal scarring in five and ureteral duplication in two. Golf-hole ureteral orifices were noted in two patients. The intravesical ureter was short (< 5 mm) in five patients. In spite of the normal VCU, we offered these patients endoscopic treatment of VUR by submeatal injection of Teflon or microparticulate silicone (Macroplastic). The median follow-up before treatment was 4 years (range 1-15.3 years); 0.3 episodes of acute pyelonephritis per patient-month of follow-up were noted. The frequence of preoperative and postoperative episodes of acute pyelonephritis was compared with Wilcoxon's paired analysis. The median postoperative follow-up was 3.9 years (range 1.1 months-10.2 years). RESULTS: There were no significant postoperative complications. One patient had two episodes of acute pyelonephritis during pregnancy. On the whole, 11 patients (91%) were free of recurrent pyelonephritis after treatment. Overall, 0.003 episodes of acute pyelonephritis per patient-month of postoperative follow-up were observed. The result was statistically significant (P < 0.01). CONCLUSION: Recurrent acute pyelonephritis is frequently related to VUR. Intermittent reflux can be difficult to demonstrate on voiding conventional or nuclear cystograms but can be suspected in the presence of ureteral duplication, renal scarring, or abnormal ureteral orifices. Adult patients with recurrent episodes of upper urinary tract infection and normal cystograms should be considered for an endoscopic antireflux procedure in the presence of anatomic abnormalities commonly associated with reflux.

Acute Disease↗
PubMed2000

Oxidative stress involvement in chemically induced differentiation of K562 cells.

The erythroid differentiation of K562 cells could be achieved by exposure to several pharmacologic agents, including hemin, butyric acid (BA), and anthracycline antitumor drugs such as aclarubicin (ACLA) and doxorubicin (DOX). When used at subtoxic concentrations, these drugs induce the overexpression of erythroid genes, leading to hemoglobinization of cells. Because anthracyclines are known to generate oxidative damage, we intended to demonstrate the involvement of an oxidative stress in the chemically induced differentiation process. The addition of antioxidants to anthracycline- and BA-induced cells decreased their growth and dramatically reduced the percentage of differentiated cells at day 3. Northern blot analysis showed that antioxidants also decrease the expression of erythroid genes and related transcription factors in induced cells. Moreover, analyses of oxidative stress markers showed that treatment with BA, ACLA, and DOX lead to a decrease in reduced glutathione and antioxidant enzymes (glutathione peroxidase [GPx], glutathione reductase [GRase], CuZn superoxide dismutase [SOD], and catalase [CAT]). In addition, DOX increased thiobarbituric acid reactants (TBARs), and MnSOD activity was decreased by BA and DOX. Finally, the production of reactive oxygen species (ROS) by differentiating agents was demonstrated using the dihydroethidium probe in a microspectrofluorometric assay. Altogether, these results strongly suggest the involvement of an oxidative stress generated by BA or anthracyclines as the first step in the irreversible differentiation process. Additionally, these results underline the differences between BA, ACLA, and DOX molecular mechanisms.

Aclarubicin↗
PubMed2000

Exserohilum israeli, a new species isolated from soil from Timna Park (Israel), and its physiological properties.

Fungi isolated from soil in Timna Park (Israel) were found to belong to a new species of Exserohilum for which the name Erserohilum israeli sp. nov. is proposed. The main physiological properties of members of this species are discussed and the influence of temperature and copper concentrations on the growth and morphology of the fungus were investigated.

Anti-Bacterial Agents↗
PubMed2000

[An uncommon tumor of the urinary bladder: the small cell carcinoma].

Primary small cell carcinoma of the urinary bladder is an uncommon tumor, compared to the frequency of urothelial tumors. Fifty percent of cases are combined with a non endocrine carcinomatous component. We report six new cases of this tumor, three of pure, and three associated with an urothelial carcinoma. Diagnosis is easy established by the immunohistochemical study which show the neuro-endocrine differentiation of these aggressive tumors. Pathologist needs to look for a neuro-endocrine part in all bladder cancer, as its presence modify the treatment. Chemotherapy is used in these cancers, due to their high metastatic power. Places of radical surgery and radiotherapy need to be specified.

Adult↗
PubMed2000

[Symptom scores: what do they describe exactly?].

OBJECTIVE: Standardized symptom scores have been developed to evaluate voiding disorders. The most widely used in France are the IPSS and Madsen-Iversen. These self-assessment questionnaires are by definition subjective. The objective of this study was to compare the capacities of the IPSS and Madsen-Iversen score to describe the patient's voiding status and to define the patient's level of understanding of these questionnaires. PATIENTS AND METHODS: One hundred male patients were included in this prospective study. All completed an IPSS and Madsen-Iversen questionnaire. Physical examination, uroflowmetry and post-voiding bladder ultrasonography were also performed. RESULTS: The description of the voiding status was considered to be satisfactory or fairly satisfactory, with a total of 85% for IPSS and 87% for Madsen-Iversen. Understanding of the questionnaire was high with a value of 84% for IPSS and 83% for Madsen-Iversen. Neither the order of completion of the IPSS or Madsen-Iversen questionnaires nor the patient's age influenced these results. CONCLUSIONS: No difference was demonstrated between the IPSS score and the MADSEN-IVERSEN questionnaire in terms of description and comprehension. However, one out of five patients experienced difficulties completing these questionnaires.

Humans↗
PubMed1999

Degradation of phenolic and chloroaromatic compounds by Coprinus spp.

Three species of Coprinus: C. sp, C. cinereus and C. micaceus were compared on solid media for some aspects of their physiological behaviour and cultural requirements (temperature, pH, substrate). Constitutive extracellular enzymatic activities were also determined. The Coprinus spp. exhibited different physiological and cultural features. Cultures of the 3 Coprinus species in synthetic liquid medium showed an efficient degradation of phenolic lignin model compounds (catechol, ferulic acid, guaiacol, phenol, protocatechuic acid syringic acid and vanillic acid) and pentachloronitrobenzene, while pentachlorophenol was not metabolized after 5 days perhaps because of a strong adsorption on mycelial biomass. It was suggested that phenoloxidases were not necessarily required for the metabolization of these compounds. Coprinus species may share a common degrading system for monomeric phenolic and chloroaromatic compounds.

Benzene↗
PubMed1999

Menkes disease: study of the mitochondrial respiratory chain in three cases.

Mitochondrial oxidative metabolism in three patients with typical Menkes disease was studied. In two cases, a general decrease in all of the respiratory chain complex activities (I, II, III and IV) was observed. However, in the most severe case, these activities were entirely normal. Our results emphasize the diversity of the cellular expression of Menkes disease which can, in some cases, be associated with a mitochondrial encephalomyopathy.

Ceruloplasmin↗
PubMed1999

Characterisation of the acoustic cavitation cloud by two laser techniques.

An experimental investigation of the size and volumetric concentration of acoustic cavitation bubbles is presented. The cavitation bubble cloud is generated at 20 kHz by an immersed horn in a rectangular glass vessel containing bi-distilled water. Two laser techniques, laser diffraction and phase Doppler interferometry, are implemented and compared. These two techniques are based on different measuring principles. The laser diffraction technique analyses the light pattern scattered by the bubbles along a line-of-sight of the experimental vessel (spatial average). The phase Doppler technique is based on the analysis of the light scattered from single bubbles passing through a set of interference fringes formed by the intersection of two laser beams: bubble size and velocity distributions are extracted from a great number of single-bubble events (local and temporal average) but only size distributions are discussed here. Difficulties arising in the application of the laser diffraction technique are discussed: in particular, the fact that the acoustic wave disturbs the light scattering patterns even when there are no cavitation bubbles along the measurement volume. As a consequence, a procedure has been developed to correct the raw data in order to get a significant bubble size distribution. After this data treatment has been applied the results from the two measurement techniques show good agreement. Under the emitter surface, the Sauter mean diameter D(3, 2) is approximately 10 microm by phase Doppler measurement and 7.5 microm by laser diffraction measurement at 179 W. Note that the mean measured diameter is much smaller than the resonance diameter predicted by the linear theory (about 280 microm). The influence of the acoustic power is investigated. Axial and radial profiles of mean bubble diameters and void fraction are also presented.

Journal Article↗
PubMed1999

Antimicrobial and antitumor activities of mycosporulone.

The conditions for optimal production of mycosporulone (1) are given. Its cytotoxic, antimicrobial, and antitumor activities are described. The biological activities of 1 were compared with those of known antibacterial, antifungal, and antitumor agents. The compound was particularly active against Pseudomonas aeruginosa and Staphylococcus aureus (resistant to penicillin). Compound 1 was not toxic to normal human cells (MRC(5)), although it exhibited cytotoxic activity against the human tumor cell lines MDA-MB 231 and PC(3) and the murine L-1210 leukemia cell line.

Anti-Bacterial Agents↗
PubMed1997

Soil mycoflora from the Dead Sea Oases of Ein Gedi and Einot Zuqim (Israel).

Samples were taken from the top 10 cm of soils from 24 points in the Ein Gedi area. Among 329 isolates, 142 species were identified: 11 genera of ascomycetes, one genus of coelomycetes, 28 genera of hyphomycetes, 7 genera of zygomycetes and one yeast, in addition to some unidentified basidiomycetes. The hyphomycetes were represented by 17 dematiaceous, 9 mucedinaceous and two tuberculariaceous. Melanconiaceous and stilbellaceous genera were not found. Two new varieties of Microascus recently described were reisolated. No strict thermophiles or halophiles were obtained. There is apparently no very characteristic or specific fungal flora of the Dead Sea Oases although it was different from that found in the desert soil surrounding this area.

Ecology↗