Effects of chronic noise exposure on spatial learning and memory of rats in relation to neurotransmitters and NMDAR2B alteration in the hippocampus.

Objectives: The purpose of this study was to examine the effects of noise exposure on spatial learning and memory and associated mechanisms in the hippocampus (HIP).

Methods: Forty-eight male SD rats were grouped as: A, control; B, Morris water maze (MWM) training group; C, noise exposure group; and D, noise exposure followed by MWM training group. The influence of noise stress on spatial learning and memory in rats was assessed in hidden platform acquisition training and probe trial testing in MWM.

Changes in Guinea pig cochlear hair cells after sound conditioning and noise exposure.

Sound conditioning has reduced noise-induced hearing loss in experimental mammalian animals and in clinical observation. Forty guinea pigs were grouped as: A, control; B, conditioning noise exposure group; C, high level noise exposure group; and D, conditioning noise exposure followed by a high level noise exposure group. Auditory brainstem response thresholds were measured.

Mechanisms of inactivation of hepatitis A virus in water by chlorine dioxide.

In this study, to elucidate the mechanisms of inactivation of hepatitis A virus (HAV) by chlorine dioxide, cell culture, enzyme-linked immunosorbent assay (ELISA), and long-overlapping RT-PCR were used to detect the infectivity, antigenicity, and entire genome of HAV before and after disinfection. The results revealed the complete inactivation of infectivity after a 10-min exposure to 7.5mg of chlorine dioxide per liter; and the highest level of sensitivity in the 5'non-translated regions (5'NTR) (the sequence from bp 1 to 671), inactivation of which took as much time as the inactivation of infectivity of HAV by chlorine dioxide; the complete destruction of antigenicity after a 10-min exposure to 7.

Mechanisms of inactivation of hepatitis a virus by chlorine.

The study was intended to investigate the feasibility of reverse transcription-PCR (RT-PCR) for evaluation of the efficacy of inactivation of viruses in water and to elucidate the mechanisms of inactivation of hepatitis A virus (HAV) by chlorine. Cell culture, enzyme-linked immunosorbent assay, and long-overlap RT-PCR were used to detect the infectivity, antigenicity, and entire genome of HAV inactivated or destroyed by chlorine. The cell culture results revealed the complete inactivation of infectivity after 30 min of exposure to 10 or 20 mg of chlorine per liter and the highest level of sensitivity in the 5' nontranslated regions (5'NTR), inactivation of which took as much time as the inactivation of infectivity of HAV by chlorine.