N-nitrosamines induced infertility and hepatotoxicity in male rabbits.

N-nitrosamines are widely spread environmental pollutants of well-known toxicity and carcinogenicity in various animal species. These compounds are metabolically activated by cytochrome P450 system predominantly in the liver and in other tissues into more active metabolites leading to generation of both alkylating agents that alkylate DNA and reactive oxygen species. In the current study, we investigated the influence of four types of N-nitrosamines that are commonly present in the environment [methyethylnitrosamine, (MEN), diethylnitrosamine (DEN), diphenylnitroasamine (DPN) and dimethylnitrosamine (DMN)] on both livers and testes of male rabbits through assessment of 17 ß-hydroxysteroid dehydrogenase (17 ß-HSD) activity. The protein expression of the three cytochrome P450s (CYP11A1, CYP19A1, and CYP21A2) is involved in the steroidogenesis. The levels of testosterone (T) and estradiol (E2) were also determined in the plasma of N-nitrosamines-treated rabbits after one, four-, eight- and twelve weeks of treatment of male New Zealand rabbits with an oral dose of 0.5 mg/kg B.W/day of each compound. In addition, activities of glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT) and levels of free radicals measured as thiobarbituric acid reactive substances (TBARS), and reduced glutathione (GSH) level were quantified in both livers and testes. The present study showed that levels of free radicals (TBARS) were markedly increased, whereas GSH levels were depleted in the tissues of both livers and testes after treatment of rabbits with any of N-nitrosamines. In addition, all tested N-nitrosamines inhibited the activities of antioxidant enzyme activities (GR, GST, SOD, and CAT) in hepatic and testicular tissues of rabbits after 12 weeks of treatment. Histopathological examination showed that N-nitrosamines caused lymphocytic infiltration with vascular degeneration and necrosis, congestion of central vein with RBCs hemolysis, dilated sinusoids, as well as fibrosis around portal areas were seen in hepatic tissues. In the testes, histopathological examination displayed disorganized seminiferous tubules with degeneration of germinal epithelium and Sertoli cells. Also, spermatogenic cells had pyknotic nuclei and others were detached from basement membranes of seminiferous tubules, edema was seen between seminiferous tubules. Moreover, the present data showed that MEN and DEN down-regulated the protein expression of both CYP19A1 and 21A2 in both livers and testes of male rabbits. In addition, both MEN and DEN decreased levels of testosterone and estradiol in plasma of treated rabbits. On the one hand, DMN and DPN markedly up-regulated the protein expression of CYP19A1 in both hepatic and testicular tissues of treated rabbits. These compounds potentially increased estradiol and decreased testosterone levels. On the other hand, no correlation was found between the expression of CYP11A1 and levels of both testosterone and estradiol. It is concluded that most of tested N-nitrosamines induce different changes, which could be a new mechanism of infertility due to exposure to N-nitrosamines from different environmental sources.

Optical and positron annihilation spectroscopic studies on PMMA polymer doped by rhodamine B/chloranilic acid charge transfer complex: Special relevance to the effect of γ-ray irradiation.

Polymeric sheets of poly (methylmethaclyerate) (PMMA) containing charge transfer (CT) complex of rhodamine B/chloranilic acid (Rho B/CHA) were synthesized in methanol solvent at room temperature. The systematic analysis done on the Rho B and its CT complex in the form of powder or polymeric sheets confirmed their structure and thermal stability. The IR spectra interpreted the charge transfer mode of interaction between the CHA central positions and the terminal carboxylic group. The polymer sheets were irradiated with 70 kGy of γ radiation using (60)Co source to study the enhanced changes in the structure and optical parameters. The microstructure changes of the PMMA sheets caused by γ-ray irradiation were analyzed using positron annihilation lifetime (PAL) and positron annihilation Doppler broadening (PADB) techniques. The positron life time components (τ(i)) and their corresponding intensities (I(i)) as well as PADB line-shape parameters (S and W) were found to be highly sensitive to the enhanced disorder occurred in the organic chains of the polymeric sheets due to γ-irradiation.

Xylometazoline pretreatment reduces nasotracheal intubation-related epistaxis in paediatric dental surgery.

BACKGROUND: Epistaxis is the most common complication encountered during nasotracheal intubation (NTI) in children. The aim of this study was to test the efficacy of prophylactic intranasal admixture of xylometazoline and local anaesthetic gel in reducing epistaxis after NTI in children. METHODS: Children presenting for dental procedures requiring NTI were randomly allocated into two groups: Group 1 (xylometazoline group, n=53) and Group 2 (control group, n=51). After sevoflurane inhalation induction, the more patent nostril in each subject was lubricated with lidocaine 2% (1 ml) jelly, followed by 0.6 ml of either xylometazoline hydrochloride 0.1% nasal drops (Group 1) or sodium chloride 0.9% (Group 2). The presence and extent of bleeding occurring during intubation, extubation, or both and navigability through the nasal passage were assessed. RESULTS: The incidence and severity of bleeding were significantly reduced between the study group (7.5%) compared with the control group (27.5%; P<0.01). Navigability was similar in both groups. CONCLUSIONS: Admixture of intranasal xylometazoline 0.1% drops and lidocaine 2% jelly reduced the incidence and severity of epistaxis after NTI in preschool children.

Experimental studies and nuclear model calculations on proton-induced reactions on (nat)Se, (76)Se and (77)Se with particular reference to the production of the medically interesting radionuclides (76)Br and (77)Br.

Excitation functions of the reactions (nat)Se(p,x)(75,76,77,82)Br, (76)Se(p,xn)(75,76)Br, (76)Se(p,x)(75)Se and (77)Se(p,xn)(76,77)Br were measured from their respective thresholds up to 40 MeV, with particular emphasis on data for the production of the medically important radionuclides (76)Br and (77)Br. The conventional stacked-foil technique was used. The samples were prepared by a sedimentation process. Irradiations were performed using the compact cyclotron CV 28 and the injector of COSY, both at the Research Centre Jülich. In order to validate the data, nuclear model calculations were performed using the code ALICE-IPPE which is based on the preequilibrium-evaporation model. Good agreement was found between the experimental and theoretical data, except in the high-energy region where the calculated data were somewhat higher. All the measured excitation curves were compared with the data available in the literature. From the experimental data the theoretical yields of all the investigated radionuclides were calculated and plotted as a function of proton energy. The calculated yield of (77)Br from the (nat)Se(p,x)(77)Br process over the energy range E(p)=25-->15 is 72.7 MBq/microAh and from the (77)Se(p,n)(77)Br reaction over E(p)=15-->6 MeV it is 86.2 MBq/microAh. The yield of (76)Br from the (76)Se(p,n)(76)Br reaction for E(p)=15-->8 is 360.1 MBq/microAh and from the (77)Se(p,2n)(76)Br reaction for E(p)=28-->18 MeV it is 879.2 MBq/microAh. The radionuclidic impurity levels are discussed.