Oxidative stress and histopathological changes induced by methylthiophanate, a systemic fungicide, in blood, liver and kidney of adult rats

Background: Methyl-thiophanate (MT), a fungicide largely used in agriculture throughout the world including Tunisia, protects many vegetables, fruits and field crops against a wide spectrum of fungal diseases. Oxidative stress has been proposed as a possible mechanism involved in MT toxicity on non-target organism.Methods: In the present study, the effect of MT injected intraperitoneally to adult rats at 300 or 500 mg/kg of body weight was studied on blood, liver and kidney.Results: Our results showed 3 days after MT injection, a significant decrease in hemoglobin and hematocrit values. A disruption in total white blood cells and platelets also occurred. Accordingly, an increased in malondialdehyde, H2O2 and advanced oxidation protein levels in liver and kidney were noted with the two doses. A significant change in plasma biomarkers and organ enzymatic and non-enzymatic activities were observed after MT treatment. The modifications in biochemical parameters were substantiated by histopathological data.Conclusion: These data confirmed the pro-oxidant effects of this fungicide. Accordingly, care must be taken to avoid mammalian and human exposure to MT.Keywords: Methyl-thiophanate, white blood cells, red blood cells, liver, kidne

Oxidative stress and histopathological changes induced by methylthiophanate, a systemic fungicide, in blood, liver and kidney of adult rats.

Background: Methyl-thiophanate (MT), a fungicide largely used in agriculture throughout the world including Tunisia, protects many vegetables, fruits and field crops against a wide spectrum of fungal diseases. Oxidative stress has been proposed as a possible mechanism involved in MT toxicity on non-target organism. Methods: In the present study, the effect of MT injected intraperitoneally to adult rats at 300 or 500 mg/kg of body weight was studied on blood, liver and kidney. Results: Our results showed 3 days after MT injection, a significant decrease in hemoglobin and hematocrit values. A disruption in total white blood cells and platelets also occurred. Accordingly, an increased in malondialdehyde, H2O2 and advanced oxidation protein levels in liver and kidney were noted with the two doses. A significant change in plasma biomarkers and organ enzymatic and non-enzymatic activities were observed after MT treatment. The modifications in biochemical parameters were substantiated by histopathological data. Conclusion: These data confirmed the pro-oxidant effects of this fungicide. Accordingly, care must be taken to avoid mammalian and human exposure to MT

Approximation of the Fixed Point of the Product of Two Operators in Banach Algebras with Applications to Some Functional Equations

Making use of the Boyd-Wong fixed point theorem, we establish a new existence and uniqueness result and an approximation process of the fixed point for the product of two nonlinear operators in Banach algebras. This provides an adequate tool for deriving the existence and uniqueness of solutions of two interesting type of nonlinear functional equations in Banach algebras, as well as for developing an approximation method of their solutions. In addition, to illustrate the applicability of our results we give some numerical examples

Approximation of the Fixed Point of the Product of Two Operators in Banach Algebras with Applications to Some Functional Equations

Making use of the Boyd-Wong fixed point theorem, we establish a new existence and uniqueness result and an approximation process of the fixed point for the product of two nonlinear operators in Banach algebras. This provides an adequate tool for deriving the existence and uniqueness of solutions of two interesting type of nonlinear functional equations in Banach algebras, as well as for developing an approximation method of their solutions. In addition, to illustrate the applicability of our results we give some numerical examples

Fixed point results for multivalued mapping with closed graphs in generalized Banach spaces

In this paper, by establishing a new characterization of the notion of upper semi-continuity of multi-valued mappings in generalized Banach spaces, we prove some Perov type fixed point theorems for multi-valued mappings with closed graphs. Moreover, we derive some Krasnoselskii's fixe point results for multi-valued mappings in generalized Banach spaces. Our results are applied to a large class of nonlinear inclusions systems.Comment: no comment

H2O2 determination at iron-rich clay modified electrodes

International audienc

Investigation of human papillomavirus in bladder cancer in a series of Tunisian patients

Background: Association between human papillomavirus (HPV) infection and the development of bladder cancer is variable. Furthermore, the prevalence of HPV DNA in bladder carcinoma subtypes varies from study to study. To clarify the impact of HPV infection on the development of bladder carcinoma, we performed a retrospective study on Tunisian patients for the status of HPV infection in urothelial carcinoma, squamous cell carcinoma and adenocarcinoma. Methods: A total of 125 formalin-fixed, paraffin-embedded archival tissue of bladder carcinoma were reviewed and classified according to the World Health Organization (WHO) classification of tumors (119 urothelial carcinomas, five squamous carcinomas and one adenocarcinoma). Anogenital HPV DNA detection was performed with three different polymerase chain reaction (PCR) techniques. The first one, using primers pU-2R/pU-1M specific to high-risk oncogenic HPV. The second one, using primers PU-2R/PU-31B specific to low-risk oncogenic HPV and the third one, employing consensus primers (E1-547R/E1-350L). Results: No evidence of HPV infection was detected by morphological examination and PCR in any case of bladder carcinoma. Conclusion: Our study shows that anogenital HPV investigated are not associated with the pathogenesis of bladder cancer in Tunisia, however, the possibility that other subtypes of HPV contribute to bladder carcinogenesis remains to be clarified

Investigation of human JC and BK polyomaviruses in breast carcinomas

We have previously showed the presence of the simian virus 40 (SV40) and the mouse mammary tumor virus (MMTV)-like in a significant proportions of Tunisian breast carcinomas. However, to date there are no published studies concerning evaluation of the possible implication of the human polyomaviruses JC (JCV) and BK (BKV) in breast carcinomas. The presence of JCV and BKV DNA was investigated by PCR in a 123 primary breast carcinomas and matched adjacent non-tumor breast tissues. The results were correlated to clinicopathological and virological parameters. JCV T-antigen DNA was detected in 23% of breast carcinoma cases; however, all cases were negative for BKV. JCV T antigen PCR products were further confirmed as authentic JCV genome by direct sequencing. JCV was found in invasive ductal carcinomas (28/112 cases) but not in invasive lobular carcinomas (0/5) or medullary carcinomas (0/6). JCV DNA presence correlates inversely with the expression of estrogen (P = 0.022) and progesterone (P = 0.008) receptors. JCV DNA presence correlates also with "triple negative" phenotype (P = 0.021). With regard to virological data, a trend toward an inverse correlation was noted between the presence of JCV and SV40 (P = 0.06). Moreover, significant correlation was found between multiple viral infection (JCV, and/or SV40, and/or MMTV-like in the same tumor) and "triple negative" phenotype (P = 0.001) and also with p53 accumulation (P = 0.028). To the best of our knowledge, this is the first study demonstrating the presence of JCV in a subset of breast carcinomas. Also our results suggest that "triple negative" breast carcinomas are viral-related tumors

Contribution of epigenetic alteration of BRCA1 and BRCA2 genes in breast carcinomas in Tunisian patients

Objective: The aim of this study was to evaluate the contribution of the BRCA1 and BRCA2 promoter methylation in the pathogenesis of sporadic breast cancer in Tunisian patients. Methods: Breast carcinoma tissues (n=117) and available paired normal breast tissues (n=65) from Tunisian women who had no family history were investigated for the methylation status of BRCA1 and BRCA2 promoters using methylation-specific PCR. Breast specimens from women without carcinoma (16 fibroadenomas and 5 mastopathies) were used as control. Results: Hypermethylation of BRCA1 and BRCA2 promoters was detected respectively in 60.7% and 69.2% of the carcinoma tissues, and in only 7.7% and 4.6% of the paired normal breast tissues. None of the fibroadenomas and mastopathies showed hypermethylation. Correlations were found between BRCA1 and BRCA2 hypermethylation and decrease in their mRNA expression (p=0.02 and p=0.009, respectively). Moreover, BRCA1 methylation correlates with patients age (p=0.01) and triple negative (ER-, PR-, HER2-) tumors (p=0.01). Patients with methylated BRCA1 and/or BRCA2 had a significant prolonged survivals compared to those with unmethylated tumors (p=0.002). Conclusion: Our results suggest an important role of BRCA1 and BRCA2 promoter methylation in breast cancer development in the Tunisian population