A high spatial resolution outdoor dose rate map of the Rio de Janeiro city, Brasil, risk assessment and urbanization effects.

Geophysical surveys have been widely used for geological mapping, and with appropriate ground calibration the database can be converted to radiometric surveys. Herein we present a case study of a high resolution map of the City of Rio de Janeiro, Brazil, constructed by integrating aerial and in situ (ground) measurements. This allowed assessing the influence of urbanization observed between 1978 and 2009 on radiation external exposure. Radiometric, geological and demographics databases were integrated in a Geographic Information System (GIS) facility. The average absorbed dose rate recorded for the city was 96 ± 0.3 nGy h(-1) and ranged from 22 to 152 nGy h(-1) among districts. The corresponding annual effective dose was determined as 0.09 ± 0.01 mSv. The number of people at risk per year according to the estimated natural radiation levels was 17 ± 1.4, among the 28,000 new cases estimated by the INCA (Brazilian National Cancer Institute) within a population of approximately 6.3 million people.

Tx2-6 toxin of the Phoneutria nigriventer spider potentiates rat erectile function.

The venom of the spider Phoneutria nigriventer contains several toxins that have bioactivity in mammals and insects. Accidents involving humans are characterized by various symptoms including penile erection. Here we investigated the action of Tx2-6, a toxin purified from the P. nigriventer spider venom that causes priapism in rats and mice. Erectile function was evaluated through changes in intracavernosal pressure/mean arterial pressure ratio (ICP/MAP) during electrical stimulation of the major pelvic ganglion (MPG) of normotensive and deoxycorticosterone-acetate (DOCA)-salt hypertensive rats. Nitric oxide (NO) release was detected in cavernosum slices with fluorescent dye (DAF-FM) and confocal microscopy. The effect of Tx2-6 was also characterized after intracavernosal injection of a non-selective nitric oxide synthase (NOS) inhibitor, L-NAME. Subcutaneous or intravenous injection of Tx2-6 potentiated the elevation of ICP/MAP induced by ganglionic stimulation. L-NAME inhibited penile erection and treatment with Tx2-6 was unable to reverse this inhibition. Tx2-6 treatment induced a significant increase of NO release in cavernosum tissue. Attenuated erectile function of DOCA-salt hypertensive rats was fully restored after toxin injection. Tx2-6 enhanced erectile function in normotensive and DOCA-salt hypertensive rats, via the NO pathway. Our studies suggest that Tx2-6 could be important for development of new pharmacological agents for treatment of erectile dysfunction.