Author Correction: Radiological Investigation of High Background Radiation Areas.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Radiological Investigation of High Background Radiation Areas.

In this paper, we used the Hyper-Pure Germanium (HPGe) detector to measure 30 samples which are collected from north of Nile Delta near Rosetta beach in Egypt. The activity of primordial radionuclides, such as 238U, 235U, 232Th, and 40K was estimated. Concentrations ranged between 36.5-177.4, 50-397.5 and 56.1-168.9 Bq.kg-1 for 238U, 232Th and 40K respectively. Activity concentration of 235U and the variation in uranium isotopic ratio 235U/238U was calculated. External hazard indices (Hex) (or radium equivalent activity Raeq), activity concentration indices (I), alpha index (Iα), absorbed outdoor gamma dose rate (Dout), effective outdoor gamma dose rate (Eout) and Excess Lifetime Cancer Risk (ELCR) due to different samples are estimated. External hazard indices (Hex) are ranged between 0.32-2.04, radium equivalent activity (Raeq) are ranged between 118.67-753.91, the activity concentration indices (I) are 0.42-2.61, and alpha index (Iα) are 0.18-0.89. External hazard indices (Hex) in some samples more than unity then it exceeds the upper limit of exposure. Also, the radium equivalent activities (Raeq) are higher than the exemption limits (370 Bq.kg-1).

Anticancer and Radiosensitization Efficacy of Nanocomposite Withania somnifera Extract in Mice Bearing Tumor Cells.

The objective of the present study was to evaluate the anticancer and radio-sensitizing efficacy of a Withania somnifera extract/Gadolinium III oxide nanocomposite (WSGNC) in mice. WSGNC was injected to solid Ehrlich carcinoma-bearing mice via i.p. (227 mg/kg body weight) 3 times/week during 3 weeks. Irradiation was performed by whole body fractionated exposure to 6Gy, applied in 3 doses of 2 Gy/week over 3 weeks. Biochemical analyses as well as DNA fragmentation were performed. Treatment of solid Ehrlich carcinoma bearing mice with WSGNC combined with γ-radiation led to a significant decrease in the tumor size and weight associated with a significant decrease in mitochondrial enzyme activities, GSH content and SOD activity as well as a significant increase in caspase-3 activity, MDA concentration and DNA fragmentation in cancer tissues. Combined treatment of WSGNC and low dose of γ-radiation showed great amelioration in lipid peroxidation and antioxidant status (GSH content and SOD activity) in liver tissues in animals bearing tumors. It is concluded that WSGNC can be considered as a radio-sensitizer and anticancer modulator, suggesting a possible role in reducing the radiation exposure dose during radiotherapy.

Human endometrial nuclear estrogen receptors among Norplant implant users.

Twenty-four parous women were included in this study. Sixteen cases were using the Norplant implant contraceptive system for more than 6 months (Group A) while eight cases served as matched controls in the secretory phase (Group B). Norplant implant users belonged to one of two equal subgroups according to whether they experienced regular menstrual bleeding (Subgroup A1) or prolonged episodes of amenorrhoea (Subgroup A2). Endometrial samples were processed for nuclear oestrogen receptor assay and for evaluation of the receptor's binding affinity to oestrogen. The results showed marked reduction in endometrial nuclear oestrogen receptors in Norplant users compared with controls as the majority of users had undetectable receptor levels. This down-regulation effect was significantly more pronounced among women with prolonged episodes of amenorrhoea. The affinity section of the study revealed no significant differences between groups or subgroups probably due to the small number of subjects with detectable receptor concentrations for comparison. These data may help in the understanding of contraceptive mechanisms and menstrual associated problems, and in the development of therapeutic measures.

Gossypol as an inducer or inhibitor in Spodoptera littoralis larvae.

Gossypol occurs naturally in the pigment glands in cotton. It has a role in protecting cotton plants from insect pests such as bollworms, yet it was not toxic to the cotton leafworm larvae Spodoptera littoralis up to 2-5% concentration in artificial diet or at 125 micrograms/ larva by topical application. The compound inhibited protease and lipid peroxidase activities in larvae with in vitro I50 values of 1.5 X 10(-3)M, and 4.4 X 10(-4)M respectively. When gossypol was fed to Spodoptera larvae, it stimulated the microsomal N-demethylase in vitro. This inductive effect was time-dependent similar to that of phenobarbital. Gossypol stimulates ATPase at lower concentrations and inhibited it at higher concentrations. The I50 for mitochondrial ATPase was 1.7 X 10(-4)M, while the corresponding values for DDT and fenvalerate were 1.1 X 10(-4)M and 7.0 X 10(-4)M respectively. Gossypol at 1.5% concentration in the diet reduced the larval weight to 50% of the control within two days, and increased the duration of each larval stage. The number of eggs and their hatchability was seriously decreased in larvae treated for three consecutive generations. Such an effect can be attributed to the ability of gossypol to interfere with protein bio-synthesis.

Interactions of acetylcholine receptors with organic mercury compounds.

Micromolar concentrations of methylmercury and several organic mercury fungicides were found to block binding of [3H]acetylcholine (ACh) to the ACh-receptor of the electric organ of the electric ray, Torpedo ocellata. The same compounds had little or no effect on the catalytic activity of ACh-esterase of the same tissue. [14C]Methyl-mercury bound to the purified ACh-receptor with high affinity (Kd=7micrometer) and there were 6.5 +/- 0.5 binding sites for each ACh-binding site. Binding of methylmercury was highly cooperative with a Hill coefficient of 2.6. This binding was irreversible by redialysis in methylmercury - free medium, however, the bound [14C]methylmercury was easily displaced from the receptor protein with micrometer concentrations of BAL or penicillamine. Methylmercury also blocked binding of [3H] nicotine and [3H]pilocarpine to the nicotinic and muscarinic ACh-receptors of the rat brain, respectively. The data suggest that the ACh-receptor may be a target for methylmercury and other organic mercury compounds.