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D Renault

Publications and source records attributed to D Renault.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of Prussian blue and apple-pectin efficacy on 137Cs decorporation in rats.

Cesium-137 (137Cs) is one of the most important nuclear fission elements that contaminated the environment after the explosion of the Chernobyl nuclear power plant in Ukraine (1986). The aim of the study was to compare the efficacy of two chelating agent, Prussian blue and apple-pectin on 137cesium decorporation in rats. Rats were intravenously injected with a solution of 137cesium (5 kBq per rat). Chelating agents, Prussian blue or apple-pectin were given immediately after Cs contamination and during 11 days by addition of each chelating agent in drinking water at a concentration corresponding to 400 mg kg(-1) day(-1). Efficiency was evaluated 11 days after contamination (at the end of treatment) through their ability to promote Cs excretion and to reduce the radionuclide accumulation in some retention compartments (blood, liver, kidneys, spleen, skeleton and in the remaining carcass). In these conditions after treatment with Prussian blue a fivefold increase in fecal excretion of Cs was observed and was associated with a reduction in the radionuclide retention in the main organs measured. In contrast, no significant differences were observed between untreated rats and rats treated with apple-pectin. These observations were discussed in terms of ability of pectins to bind Cs and compared to recently published results obtained after treatment of Cs-contaminated children with this chelate.

Animals↗
PubMed2006

Changes in free amino acids in Alphitobius diaperinus (Coleoptera: Tenebrionidae) during thermal and food stress.

Temporal changes in free amino acid pools are examined in starved and cold-exposed (10 degrees C) beetles (Alphitobius diaperinus) (control beetles; 4, 7, 14, 28 and 56 days of cold-exposure). The range of individual responses and the effect of gender on survival and free amino acid levels are evaluated. Females survived significantly longer (Lt50 and Lt90) than males under stressing conditions. Pro, Gln, Ala, Arg and Thr are the major components of the free amino acid pool in the whole body of adult beetles. Multivariate analysis indicates that the duration of exposure explains most of the observed variation in amino acid levels, while sex effect is not significant. Moreover, amino acid levels fluctuate strongly within each sampled date, revealing a high inter-individual heterogeneity. However, this heterogeneity decreases after four weeks of cold-exposure and starvation. The increase in Ala level and the concomitant decrease of Pro after four weeks suggest that Pro might be an important fuel for metabolism when fat reserves are reduced. We conclude that changes in free amino acid pools are due to a combination of reduced individual heterogeneity, cold-acclimation and amino acid degradation for energetic purposes.

Acclimatization↗
PubMed2001

[Small cell lung cancer revealed by extramembranous glomerulonephritis].

We describe a case of small-cell lung cancer limited to the thorax but with malignant pleural effusion in a 47-year-old man that was revealed by a nephrotic syndrome due to membranous glomerulonephritis (MGN). Chemotherapy led to a partial tumor response with total resolution of the nephrotic syndrome. Tumor relapse did not provoke proteinuria. Primary lung cancer is the cause of about 3% of all cases of MGN and 40% of tumor-related MGN. There are 49 cases of tumor-related MGN in the literature, including 9 cases of small-cell lung cancer.

Antineoplastic Agents↗
PubMed2000

A sexually dimorphic response in supercooling temperature, enhanced by starvation, in the lesser mealworm Alphitobius diaperinus (Coleoptera: Tenebrionidae).

The effect of starvation on supercooling temperature (SCP) distribution was investigated in adults and larvae of Alphitobius diaperinus (Coleoptera: Tenebrionidae).The mean values for SCPs of adults fed at 20 degrees C were -14.5+/-2.4 degrees C (31 males) and -10.3+/-1.3 degrees C (29 females). The distribution of the SCPs of these control adults was unimodal. No significant differences were observed in either mean wet weight or mean dry weight between males and females.The mean values for SCPs of adults starved for 1 month at 20 degrees C were found to be bimodal due to sexual dimorphism. The mean SCPs for males was lower (-17+/-2.6 degrees C; 28) than that for females (-11.2+/-1.8 degrees C; 26). No significant differences were observed in either mean dry weight or wet weight between males and females.The SCPs of both fed and starved larvae, kept for 1 month at 20 degrees C were -12.3+/-2.4 degrees C (fed) and -18.0+/-2.6 degrees C (starved).

Journal Article↗
PubMed2000

Kinetics of DNA adduct formation and removal in mouse hepatocytes following in vivo exposure to 5,9-dimethyldibenzo[c,g]carbazole.

5,9-Dimethyldibenzo[c,g]carbazole (DMDBC), a potent mouse hepatocarcinogen, has been shown to induce a non-linear increase in mutant frequency in the liver of the transgenic MutaMouse. To gain insight into the mechanisms underlying the mutagenicity of DMDBC in vivo, DNA damage formation and removal were monitored in mouse hepatocytes over 4-144 h after a single skin application of 10 or 90 mg/kg DMDBC. DNA adducts were measured by (32)P-post-labeling. DNA repair was assessed by: (i) the unscheduled DNA synthesis (UDS) assay, which measures [(3)H]thymidine incorporation into hepatocyte DNA undergoing excision repair; (ii) the Comet assay, which detects DNA strand breaks transiently produced between the incision and rejoining steps of the excision repair process. A plateau of approximately 400 DNA adducts/10(8) nucleotides was reached 24 h after treatment with 10 mg/kg and remained unchanged until 144 h. UDS activity was significantly induced at 15 and 24 h, while no DNA strand breaks were observed at any sampling time. These results suggest that DNA repair mechanisms were efficiently induced and the formation of a high degree of DNA damage was avoided at this dose level. Following exposure to 90 mg/kg DMDBC, the number of DNA adducts increased sharply to a maximum at 24 h ( approximately 8000/10(8) nucleotides) and then declined to approximately 500/10(8) nucleotides at 144 h. UDS activity was markedly induced from 15 to 72 h. Low levels of DNA strand breaks were observed at 24 and 48 h. The formation of large numbers of DNA adducts and the emergence of DNA strand breaks despite a strong initial induction of UDS activity suggested that DNA repair mechanisms were saturated at this dose level. This phenomenon could partly account for the non-linear induction of gene mutations previously reported in the liver of the transgenic MutaMouse.

Animals↗
PubMed1999

Kinetics of induction of DNA adducts, cell proliferation and gene mutations in the liver of MutaMice treated with 5,9-dimethyldibenzo[c,g]carbazole.

5,9-Dimethyldibenzo[c,g]carbazole (DMDBC) is a synthetic derivative of the environmental pollutant 7H-dibenzo[c,g]carbazole. DMDBC is a potent genotoxic carcinogen specific for mouse liver. Using the MutaMouse lacZ transgenic mouse model and a positive selection assay, we measured lacZ mutant frequency (MF) in the liver 28 days after a single s.c. administration of DMDBC at 3, 10, 30, 90 or 180 mg/kg. MF remained low at 3 and 10 mg/kg, but increased markedly from 30 mg/kg onwards. To investigate the reason for this non-linear response, we examined mechanisms potentially involved in mutation induction in the liver. Genotoxic effects such as DNA adduct formation were detected in 32P-post-labelling studies. Liver sections were examined for microscopic changes and cell proliferation. These parameters, and MF, were studied 2, 4, 7, 14, 21 and 28 days after a single s.c. administration of 10 or 90 mg/kg DMDBC. At 10 mg/kg, a dose found to double the MF on day 28, DNA adducts reached a level of 200-600 adducts per 10(8) nucleotides from day 4 to day 28. No changes in histology or cell proliferation were detected at this low dose. At 90 mg/kg, MF increased gradually from day 7 to day 28 (maximum 44-fold). The DNA adduct level ranged from 400 to 4500 adducts per 10(8) nucleotides on day 2, then stabilized at approximately 400 adducts per 10(8) nucleotides on day 4. An early cytotoxic effect was detected microscopically in centrilobular hepatocytes, and was followed by liver cell proliferation. These data suggest that the marked increase in MF in MutaMouse liver after treatment in vivo with DMDBC at 90 mg/kg may be explained by the induction of replicative DNA synthesis due to a cytotoxic effect, allowing the fixation of persistent DNA adducts into mutations.

Animals↗
PubMed1999

Effect of mitogenic or regenerative cell proliferation on lacz mutant frequency in the liver of MutaTMMice treated with 5, 9-dimethyldibenzo[c,g]carbazole.

The purpose of this work was to investigate the impact of cell proliferation on liver mutagenesis. The genotoxic hepatocarcinogen 5, 9-dimethyldibenzo[c,g]carbazole (DMDBC) was administered to lacZ transgenic MutaTMMice at a non-hepatotoxic dose of 10 mg/kg, which induces only a slight increase in the liver lacZ mutant frequency (MF). To determine if cell proliferation stimuli enhanced DMDBC mutagenicity, MF was analyzed in mice first receiving DMDBC 10 mg/kg, then approximately 2 weeks later, either carbon tetrachloride (CCl4, a cytotoxic agent inducing regenerative cell proliferation) or phenobarbital (PB, a mitogenic agent inducing direct hyperplasia). In preliminary studies, the extent of cell proliferation induced by CCl4, PB and DMDBC was determined in non-transgenic CD2F1 mice by means of 5-bromodeoxyuridine labeling. The labeling index was significantly increased after CCl4 and PB, while no change was detected with DMDBC. MF was then determined in MutaTMMice 28 days after initial DMDBC treatment. No increase in MF was detected in mice receiving CCl4 or PB alone. A 2- to 3-fold increase in MF was detected in mice treated with 10 mg/kg DMDBC alone. In contrast, MF was markedly increased in mice receiving DMDBC followed by proliferative treatment (15-fold with CCl4 and 25-fold with PB). These results demonstrate that expression of DMDBC-induced mutations in mouse liver largely depends on the induction of cell proliferation (by a cytotoxic or mitogenic stimulus) and illustrate that MutaTMMouse is a valuable tool to investigate the early events of liver carcinogenesis.

Animals↗
PubMed1999

Kinetics of induction of DNA damage and lacZ gene mutations in stomach mucosa of mice treated with beta-propiolactone and N-methyl-N'-nitro-N-nitrosoguanidine, using single-cell gel electrophoresis and MutaMouse models.

beta-Propiolactone (BPL) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) are two direct alkylating agents that induce multiple genetic lesions and tumors in the rodent stomach. We measured the kinetics of the induction of DNA damage by using the single-cell gel electrophoresis assay (SCGE) and the induction of gene mutations by using the MutaMouse model in the glandular stomach mucosa of mice exposed to a single oral administration of BPL or MNNG. The aims were to determine the optimal sampling time and to investigate the cause-effect relationship between DNA damage and gene mutations. The induction of comets, evaluated in individual cells with the tail moment, was analyzed 1, 2, 4, 24, and 72 hr after a single oral administration of 25 mg/kg BPL or 20 mg/kg MNNG. The effects of both compounds were most intense at the earlier sampling times (1-2 hr), tailing off 4 hr after treatment and becoming undetectable at 72 hr. The lacZ mutant frequency (MF) was measured 3, 7, 14, 28, and 50 days after a single oral administration of 150 mg/kg BPL or 100 mg/kg MNNG, and 3 and 14 days after a single administration of 25 mg/kg BPL or 20 mg/kg MNNG. The MF was strongly enhanced at the highest doses and all sampling times, the most marked effects being observed 14 days (11.1-fold) and 28 days (19.0-fold) after BPL and MNNG administration, respectively. At the lowest doses, only a small increase in MF ( approximately 2.5- to 3.5-fold) was found at both sampling times. Primary DNA damage detected with SCGE shortly after treatment (1-2 hr) was rapidly (3 days) transformed into stable gene mutations that remained detectable for 50 days. These results illustrate the ability and complementarity of the SCGE and MutaMouse models to assess the genotoxicity of direct alkylating agents in the mouse gastric mucosa in vivo.

Animals↗
PubMed1998

Comparative mutagenicity of 7H-dibenzo[c,g]carbazole and two derivatives in MutaMouse liver and skin.

7H-Dibenzo[c,g]carbazole (DBC) is an environmental pollutant that produces DNA adducts and tumors in mouse liver and skin following subcutaneous injection and topical application. The two synthetic derivatives 5,9-dimethyl-DBC (DMDBC) and N7-methyl-DBC (NMDBC) induce tissue-specific lesions. DNA adducts and tumors are observed only in liver following exposure to DMDBC and only in skin following exposure to NMDBC. We used the positive selection MutaMouse model to measure the induction of mutations in the two target organs, 28 days after a single subcutaneous injection or topical application of DBC, DMDBC and NMDBC. In liver, DBC and DMDBC induced 30- to 50-fold increases in mutant frequency (MF), while NMDBC had only a weak effect, regardless of the route of administration. After topical application, DBC and NMDBC produced 3.4- to 7.9-fold increases in MF in skin, while DMDBC had a weak effect. After subcutaneous injection, the three compounds had no or weak effect in skin. This study shows gene mutations arise in the respective target organs in which primary DNA damage and tumors are observed. These results illustrate the relevance of the MutaMouse model for testing organ-specific mutagens.

Administration, Cutaneous↗
PubMed1997

Effect of ethylnitrosourea and methyl methanesulfonate on mutation frequency in Muta Mouse germ cells (seminiferous tubule cells and epididymis spermatozoa).

As part of the Germ Cell Collaborative Study, we used the positive-selection Muta Mouse model to evaluate the effects of two direct alkylating agents, ethylnitrosourea (ENU) and methyl methanesulfonate (MMS), on male germ cells. The LacZ mutation frequency in seminiferous tubule cells and epididymis spermatozoa was measured 3, 14, 25 and 50 days after a single intraperitoneal (i.p.) administration of 150 mg/kg ENU and 3 and 14 days after a single i.p. administration of 40 mg/kg MMS. Three and 14 days after ENU treatment, the mutation frequency was slightly but significantly increased in seminiferous tubule cells (3.5- and 3.6-fold, respectively), while it remained unchanged in epididymis spermatozoa. After 25 and 50 days, time-dependent increase in the mutation frequency was observed in seminiferous tubule cells (8.9- and 14.3-fold, respectively) and epididymis spermatozoa (3.4- and 7.9-fold, respectively), confirming the sensitivity of premeiotic cells to the mutagenic activity of ENU. Three and 14 days after MMS administration, the mutation frequency remained unchanged in seminiferous tubule cells and epididymis spermatozoa. The inability of Muta Mouse model to reveal the mutagenic activity of MMS was confirmed in bone marrow cells, 14 days after treatment. These data indicate that the Muta Mouse model can be used to detect the induction of gene mutations but not chromosome damage in germ cells.

Animals↗
PubMed1997

Water: where from, and for whom?

When the agricultural sector takes measures to diminish water losses, access to water for domestic purposes may be greatly reduced and community health may be adversely affected.

Agriculture↗
PubMed1996

Tissue-specific induction of mutations by acute oral administration of N-methyl-N'-nitro-N-nitrosoguanidine and beta-propiolactone to the Muta Mouse: preliminary data on stomach, liver and bone marrow.

We used the positive selection Muta Mouse model to detect organ-specific activity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and beta-propiolactone (BPL), two highly reactive alkylating agents known to induce genetic damage and tumors in rodent stomach when administered orally. Seven days after a single oral administration of MNNG (100 mg/kg) or BPL (150 mg/kg), the mutation frequency in the Muta Mouse stomach increased significantly by 6.4-fold and 8.8-fold, respectively. A slight (1.8-fold) but significant increase in mutation frequency was also observed in the livers of BPL-treated mice, but not in the livers of MNNG-treated mice or the bone marrow of MNNG- and BPL-treated animals. These data indicate that the Muta Mouse model can be used to predict the gastric specificity of genotoxic carcinogens.

Administration, Oral↗
PubMed1993

Membrane permeabilization of Listeria monocytogenes and mitochondria by the bacteriocin mesentericin Y105.

Mesentericin Y105, a bacteriocin produced by a Leuconostoc mesenteroides strain, dissipates the plasma membrane potential of Listeria monocytogenes and inhibits the transport of leucine and glutamic acid. It also induces an efflux of preaccumulated amino acids from cells. In addition, the bacteriocin uncouples mitochondria by increasing state 4 respiration and decreasing state 3 respiration. The bacteriocin inhibits ATP synthase and adenine nucleotide translocase of the organelle while the affinity of ADP for its carrier is not modified. The results suggest that mesentericin Y105 acts by inducing, directly or indirectly, pore formation in the energy-transducing membranes, especially those of its natural target.

Adenosine Triphosphate↗
PubMed1988

[Simple cysts of the testis in children. Apropos of 2 cases].

Reporting two cases of simple testicular cysts in children, the authors analyse these rare benign tumors (9 other cases in literature). The cystic dilatation first affect the rete testis, it can be partial (simple cyst) or extensive (multicystic dysplasia). The primitive perturbation would affect the mesonephrotic formations, with a defect of junction between the two different embryologic formations of the testicle and its excretor system. These tumors are revealed by a large isolated testicle, histology only makes the diagnosis. Despite their benignity, simple orchidectomy is the save treatment; enucleation is justified only when the opposite testicle is also injured.

Cysts↗
PubMed1987

[Benign cystic tumors of the testis in children].

Benign cystic testicular tumors are very uncommon in childhood. These tumors can be dysplasic or teratomatous forming two peculiar groups. First electively affect the rete testis cells realizing simple cysts or multicystic dysplasia. The authors report one case of simple cyst in a four months old boy and analyse the eight observations of the literature of similar localisation and histologic structure. Dysplasic cysts are always surrounded by cuboidal or flatted epithelium and their contain is a clear liquid. The cystic dilatation of the rete testis would be consecutive to a defect of junction between the two different embryologic formations of the testicle and its excretor system. The primitive perturbation would affect the mesonephrotic formations sometimes partial cause of simple cysts, elsewhere more extensive responsible of the multicystic dysplasia associated in maximum cases with urinary system malformations. Liquid of the cysts would be the consequence of a very early accentuation of the rete cells secretion. In a second part, the different sorts of benign cystic teratomas are exposed, in order: epidermoid cysts, dermoid cysts and benign mature teratomas. For each of them are related their histologic structure and the frequency in consideration of literature analysis. These teratomatous cystic tumors would be results of a same tumoral process of increasing differentiation. They are benign under condition to be perfectly pure, examination of the whole piece is mandatory. All these benign tumors are commonly revealed by a large isolated testicle, the echography and negative biological evaluation (alpha foetoprotein, gonadotrophin hormones) may lead to suspect the type of tumor but histology only makes the diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Dermoid Cyst↗
PubMed1981

[The mechanical properties of devices used for the fixation of femoral neck fractures (author's transl)].

The authors have studied the mechanical problems of internal fixation of femoral neck fractures, both from the theoretical and experimental point of view. They have tested stability of several types of fixation according to the obliquity of the fracture line. Three types of strain have been applied to fractured dried bone. Fixation by three parallel screws seemed to give the most stability. The authors conclude that, with this type of fixation, early weight-bearing can be resumed by patients with fractures of Pauwels type I and II, but weight-bearing is still dangerous in type III.

Biomechanical Phenomena↗