Temporary and permanent level shifts in distortion product otoacoustic emissions following noise exposure in an animal model

Noise-induced hearing loss [NIHL] is one of the most common occupational illnesses. Most of the studies on NIHL were conducted at high noise levels that people are rarely exposed to but in industries. The function of the outer hair cells [OHCs] is impaired after exposure to industrial noise. Distortion product otoacoustic emissions [DPOAEs] are useful in examination of noise-induced level shifts. To assess the function of OHCs by DPOAE temporary and permanent level shifts [TLSdp and PLSdp] in rabbits exposed to white noise at realistic levels typically found in industrial settings over a broad range of frequencies. 12 albino rabbits were divided into two groups: the experimental group rabbits which were exposed to 95 dB SPL white noise at 500-8000 Hz for 8 hrs/day for 5 consecutive days, and the control group rabbits with no exposure to noise. The function of OHCs was examined by DPOAE level [Ldp] in different occasions. The study groups were compared for DPOAE temporary and permanent level shifts [TLSdp and PLSdp] to assess the effect of noise on OHCs function. Noise-induced DPOAE levels [Ldp] were decreased up to 20.65 dB [on day 8] and 18.93 dB [on day 11] at 5888.50 Hz [p=0.081]. TLSdp and PLSdp were significantly decreased up to 17.99 dB and 16.27 dB, respectively in the experimental group. The most and least Ldp were significantly different [p<0.05]; they occurred at 5888.50 and 588.00 Hz, respectively. There were significant differences between temporary and permanent threshold shift at various frequencies [p<0.05]. These differences were mainly related to 5888.50 Hz compared to other frequencies in each ear [p<0.05]. DPOAEs are an attractive tool for obtaining information about small temporary or permanent threshold shifts, even when the pure tone audiogram is normal

Establishment of autochthonous and standard cell line derived xenograft models of glioblastoma multiform in Iran

GBM is the most common and malignant astrocity tumor and it is persistent to common treatment so, these patients have a very low survival. Several researchers around the world, including Iran, have been investigated GBM-cell line in vitro. However in vivo studies have not been fulfilled. As standard cell line [U-87MG] derived from human GBM and total GBM tumor derived from 3 patients were heterotypic ally injected into 4-6 weeks old athymic nude mice. Pathologic investigation by H and E, GFAP and Ki-67 were examined 2 months post implantation. GBM characteristics appeared in H and E and GFAP and the rate of proliferation was 6% and in direct xenograft tumor was 9% which was consistent with the pathologic result of patient. GBM Xengraft is the most suitable model for in vivo investigation and researcher can evaluate new treatments for this tumor. On the other hands, Pharmacogenomics differences in treatment response could be indicated among Iranians