Porphyrin conjugated SiC/SiOx nanowires for X-ray-excited photodynamic therapy.

The development of innovative nanosystems opens new perspectives for multidisciplinary applications at the frontier between materials science and nanomedicine. Here we present a novel hybrid nanosystem based on cytocompatible inorganic SiC/SiOx core/shell nanowires conjugated via click-chemistry procedures with an organic photosensitizer, a tetracarboxyphenyl porphyrin derivative. We show that this nanosystem is an efficient source of singlet oxygen for cell oxidative stress when irradiated with 6 MV X-Rays at low doses (0.4-2 Gy). The in-vitro clonogenic survival assay on lung adenocarcinoma cells shows that 12 days after irradiation at a dose of 2 Gy, the cell population is reduced by about 75% with respect to control cells. These results demonstrate that our approach is very efficient to enhance radiation therapy effects for cancer treatments.

TCDD and corticosterone on testicular steroidogenesis and antioxidant system of epididymal sperm in rats.

2,3,7,8-Tetrachloro dibenzo-p-dioxin (TCDD), an endocrine-disrupting environmental pollutant, has been found to cause male reproductive toxicity. Glucocorticoids have been found to influence the metabolic pathway of TCDD. Stress, which affects the male reproductive function, is marked by an increase in the level and activity of glucocorticoids in the body. The present study was carried out to understand the effect of TCDD on testicular steroidogenesis and sperm antioxidant system under the influence of increased level of corticosterone in the body. Adult male rats were treated with either TCDD (100 ng/kg bw/ day) or corticosterone (3 mg/kg bw/day) or both for 15 days. Treatment with either TCDD or corticosterone was found to suppress the levels of steroidogenic acute regulatory protein and androgen-binding protein and reduce the activities of steroidogenic enzymes in testis while increasing oxidative stress in ventral prostate, seminal vesicles and epididymal sperm. In rats treated with both TCDD and corticosterone, the suppression of testicular steroidogenesis and increase in oxidative stress observed in ventral prostate, seminal vesicles and epididymal sperm were significant as compared to TCDD alone treated rats. The levels of Fas and FasL proteins were also increased in rats subjected to either TCDD or corticosterone treatment. In rats treated with both compounds, the increase observed in testicular levels of Fas and FasL was significant as compared to TCDD alone treated rats. Effect of TCDD on testicular steroidogenesis and antioxidant system of epididymal sperm may get enhanced under increased level of glucocorticoids in the body.

Selective response inversion to NO2 and acetic acid in ZnO and CdS nanocomposite gas sensor.

High sensitivity zinc oxide (ZnO) tetrapods (TPs) have been functionalized by nucleating cadmium sulphide (CdS) nanoparticles (NPs) directly on their surface with a spotted coverage thanks to an optimized synthesis in dimethylformamide (DMF). The obtained hybrid coupled material has been used to realize a gas sensing device with a highly porous nanostructured network, in which the proper alternation of ZnO-TPs and CdS-NPs gives rise to unconventional chemoresistive behaviours. Among the different tested gases and vapours, the sensor showed a unique fingerprint response-inversion between 300 °C and 400 °C only for nitrogen dioxide (NO2) and acetic acid (CH3COOH).

Effect of restraint stress on 2,3,7,8 tetrachloro dibenzo-p-dioxin induced testicular and epididymal toxicity in rats.

Dioxins like 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) impair male reproductive system by increasing the generation of reactive oxygen species (ROS). Glucocorticoids have been found to suppress male reproductive function and also influence TCDD pathway. As stress is characterized by an increase in the level and activity of glucocorticoids, the present experiments were conducted to evaluate the effect of restraint stress on TCDD-induced testicular and epididymal toxicity. Adult male Wistar rats were subjected to either restraint stress (5 hours/day) or TCDD treatment (100 ng/kg b.w./day) or both for 15 days. Restraint stress or TCDD treatment raised the serum level of corticosterone and suppressed the testicular level of steroidogenic acute regulatory (StAR) protein and serum level of testosterone significantly. In the testis and epididymis, restraint stress or TCDD treatment raised the levels of lipid peroxidation and hydrogen peroxide and suppressed the activities of antioxidant enzymes significantly. In rats subjected to both restraint stress and TCDD treatment, a significant increase in the serum level of corticosterone and a significant decrease in the testicular level of StAR protein and serum level of testosterone were observed as compared to rats treated with TCDD alone. A significant increase in the levels of lipid peroxidation and hydrogen peroxide and a significant decrease in the activities of antioxidant enzymes were observed in the testis and epididymis of rats subjected to both restraint stress and TCDD treatment as compared to TCDD alone treated rats. Thus, restraint stress potentiates the adverse effects of TCDD on male reproductive organs.

Effects of corticosterone and 2,3,7,8-tetrachloro- dibenzo-p-dioxin on epididymal antioxidant system in adult rats.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an endocrine disruptor, causes epididymal toxicity by inducing oxidative stress. Glucocorticoids have been found to influence TCDD action in vitro and in vivo. The present experiments were set up to analyze the effects of TCDD on rat epididymal antioxidant system under the influence of increased corticosterone level. Adult male Wistar/NIN rats (70-80 days old) numbering 24 (six per group) were used in the study. Corticosterone (3 mg/kg body weight per day) or TCDD (100 ng/kg body weight per day) were administered or coadministered to rats for 15 days. Treatment with corticosterone or TCDD decreased the levels of serum testosterone significantly. In caput, corpus, and cauda fractions, administration of corticosterone or TCDD increased the levels of lipid peroxidation and hydrogen peroxide and decreased the activities of superoxide dismutase and catalase significantly. Coadministration of corticosterone and TCDD to rats decreased the levels of serum testosterone significantly as compared with rats treated with TCDD alone. In caput, corpus, and cauda fractions, the levels of lipid peroxidation and hydrogen peroxide were increased and activities of superoxide dismutase and catalase were decreased significantly as compared with rats treated with TCDD alone. Stress, characterized by increased glucocorticoid levels and activity, may enhance TCDD-induced epididymal toxicity.

Low dose of 2,3,7,8 tetrachlorodibenzo-p-dioxin induces testicular oxidative stress in adult rats under the influence of corticosterone.

2,3,7,8 Tetrachlorodibenzo-p-dioxin (TCDD), an endocrine disruptor, causes testicular toxicity by increasing the production of reactive oxygen species (ROS). Glucocorticoids have been reported to influence TCDD action in vitro. Stress, characterized by increased glucocorticoid levels, has been found to suppress the testicular function. The present experiments were set up to analyse the effects of a low dose of TCDD on the rat testis under the influence of increased corticosterone levels. TCDD (1 ng/kg b.w./day) and corticosterone (3 mg/kg b.w./day) were administered alone or together to adult male rats for 15 days. Corticosterone administration raised the levels of serum corticosterone and decreased the levels of serum testosterone significantly. In the testicular mitochondrial- and microsomal-rich fractions, corticosterone administration increased the levels of lipid peroxidation and hydrogen peroxide and decreased the activities of antioxidant enzymes like superoxide dismutase and catalase significantly. TCDD administration to rats treated with corticosterone decreased the levels of serum testosterone as compared to rats treated with corticosterone alone. The levels of lipid peroxidation and hydrogen peroxide increased and the activities of superoxide dismutase and catalase were decreased significantly in mitochondrial- and microsomal fractions of the testis of treated rats as compared to those treated with corticosterone alone. It is concluded that stress may enhance the effects of TCDD on the testis.