Evaluating the miR-302b and miR-145 expression in formalin-fixed paraffin-embedded samples of esophageal squamous cell carcinoma

Background: MicroRNAs are involved in key cellular processes regulating, and their misregulation is linked to cancer. The miR-302-367 cluster is exclusively expressed in embryonic stem and carcinoma cells. This cluster also promotes cell reprogramming and stemness process. In contrast, miR-145 is mostly regarded as a tumor suppressor, where it regulates cellular functions such as cell division, differentiation, and apoptosis. By suppressing the main pluripotency factors (OCT4, SOX2, MYC and KLF4), miR-145 silences the self-renewal program in ESCs. Therefore, the main aim of this study is to find a potential link between the expression level of hsa-miR-302b and hsa-miR-145 with tumor vs. non-tumor as well as high-grade vs. low-grade states of the esophageal tissue samples. Methods: A total number of 40 formalin-fixed, paraffin-embedded (FFPE) samples of esophageal squamous-cell carcinoma (ESCC) were obtained, and the tumor and marginal non-tumor areas delineated and punched off by an expert pathologist. Total RNA was extracted with Trizol, and cDNA synthesized using the miRCURY LNA™ Universal RT microRNA PCR Kit. Real-time reverse transcription polymerase chain reaction (RT-PCR) assays were performed using specific LNA-primers and SYBR Green master mix. Results: The expression level of miR-302b failed to show any significant difference, neither between tumor and their non-tumor counterparts, nor among tumors with different grades of malignancies (P > 0.05). In contrast, miR-145 was significantly down regulated in all grades of tumor samples (P 0.05). CONCLUSION: Our data revealed a significant down-regulation of miR-145 in ESCC tissue samples. Based on our ROC curve analysis data (AUC = 0.74, P < 0.001) miR-145 could be regarded as a potential tumor marker for diagnosis of esophageal cancer. © 2015, Academy of Medical Sciences of I.R. Iran. All rights reserved

Effects of N-Acetylcysteine on auditory brainstem response threshold shift in rabbits exposed to noise and carbon monoxide

Problem statement: Noise Induced Hearing Loss (NIHL) is one of the most important occupational disease in worldwide. NIHL has been found to be potentiated by simultaneous Carbon monoxide (CO) exposure. Exposure to noise plus CO is common in occupational and environmental settings. Free radicals have been implicated in cochlear damage resulting from exposure to noise and due to CO hypoxia This study examined whether N-Acetylcysteine (NAC) administration cause attenuation of Auditory Brainstem Response (ABR) threshold shifts resulting from noise exposure and noise plus CO exposure. Approach: Forty-two rabbits were divided into seven groups including control, noise+ saline, noise+ CO +saline, noise+ NAC, noise+ CO+ NAC, CO+ NAC and NAC alone. ABR was assessed before exposure, 1 hour and 14 days post exposure. Results: The administration of 325 mg kg-1 of NAC prior, following and post exposure to noise or noise plus CO recovered permanent ABR threshold shift at 1 and 2 kHz almost to the baseline and provided significant attenuation in permanent ABR threshold shift at 4 and 8 kHz in subjects which were exposed to noise but it did not block the potentiating of threshold elevation by CO exposure (extra threshold loss by combined exposure) at 4 and 8 kHz. Conclusion: NAC provides protective effect against hearing loss resulting from noise exposure and simultaneous exposure to noise plus CO. © 2010 Science Publications

Improvement of electromagnetic shielding effectiveness for radar frequencies (X-band) using dispersion factor

Background and aims: X-band with 8-12.5 frequencies range has various applications such as air control traffic, navy communication etc. Uncontrolled exposure with microwave can lead to adverse effect on workers. Currently, application of the shielding is a superior control for prevention of microwave exposure. This study investigated the effect of dispersion on shielding effectiveness improvement about a novel nanocomposit shiled. Methods: Nanocomposites prepared by epoxy resin and nano nickel oxide (7wt) with 2, 4 and 6 mm thicknesses. In order to investigate the effect of dispersion, 10 and 66 minutes was considered as mixing time. Nanoparticles characterized by X-ray Diffraction and Field Emission Scanning Electron Microscope. Shielding effectiveness measured with vector network analyzer. Results: Dispersion of nanoparticles in group 2-nanocomposites was better than group 1-nanocomposites. Average of percentage attenuation in group 2-nanocomposites was better than group 1- nanocomposites. The Average of shielding effectiveness for three thicknesses in group 1 was 46.5, 69.03, 70.83 and for group 2 was 52.02, 78.48 and 84.14dB, respectively. Maximum attenuation obtained by the 6mm thickness in group 2- nanocomposites at 8.8 GHz frequency (91.12). The Average of shielding effectiveness increased with increasing the thickness. Conclusion: With increasing the mixing time, the dispersion and shielding effectiveness be improved. These nanocomposites could be used as appropriate shielding for exposure control of X-band frequency in workplace and nanocomposite with 4mm thickness is appropriate shield in this study. Both 4mm and 6mm thicknesses in group 2 are useful in specific frequency such as 8.8 and 12.5 GHz.the average of percentage attenuation for above thicknesses is more than 87. © 2016; MA Healthcare Ltd. All rights reserved

Assessment of outer hair cell function and blood antioxidant status of rabbits exposed to noise and metal welding fumes

Objectives: To investigate the interaction between welding fumes and noise in causation of hearing impairment. Methods: Groups of rabbits (n = 6) were exposed to noise, welding fumes or combination of both prior to Distortion Product Otoacoustic-Emissions (DPOAEs) analysis. The function of outer hair cells (OHCs) was examined by DPOAE assessment over a broad range of frequencies. Variations in DPOAE amplitude were compared between control (n = 6) and exposed (n = 18) groups. Results: The DPOAEs levels measured at different frequencies (1379-6299 Hz) were found to decrease significantly (P &lt; 0.05) in rabbits exposed to 110 dB sound pressure level (SPL) broadband noise (8 h/day, 12 days). In rabbits, exposed to carbon-steel welding fumes alone (157 mg/m3), the threshold shift was limited to the high frequencies (2759-6299 Hz), whereas, mixed exposure to noise and fumes resulted in reduction of DPOAEs at all the frequencies. Changes in DPOAEs were associated with increased susceptibility of erythrocytes to oxidation (P &lt; 0.05). Exposure to noise or fumes alone or simultaneously, suppressed total antioxidant ability of plasma as measured by ferric reducing ability of plasma (FRAP). Noise alone or in combination with fumes resulted in depletion of blood glutathione (GSH). Despite suppression of FRAP in the exposed groups, GSH was found to remain unchanged due to welding fumes suggesting that antioxidants other than GSH are affected by toxicants present in metal welding fumes. Conclusion: Exposure to very high levels of welding fumes can increase noise-related effects on OHC function by extending hearing threshold shift to wide band frequencies. © 2006 Elsevier Ireland Ltd. All rights reserved

Effects of whole body vibration on outer hair cells' hearing response to distortion product otoacoustic emissions

Whole body vibration (WBV) is one of the most vexing problems in industries. There is a debate about the effect of WBV exposure on hearing system as vibration-induced hearing loss. The purpose of this study was to investigate outer hair cells' (OHCs') hearing response hearing response to distortion product otoacoustic emissions (DPOAEs) in rabbits exposed to WBV. It was hypothesized that the DPOAE response amplitudes (A dp) in rabbits exposed to WBV would be lower than those in control rabbits not exposed to WBV. New Zealand white (NZW) rabbits as vibration group (n�=�6, exposed to WBV in the z-axis at 4-8 Hz and 1.0 ms-2 root mean square for 8 h per day during five consecutive days) and NZW rabbits as control group (n�=�6, not exposed to any WBV) were participated. A dp and noise floor levels (L nf) were examined on three occasions: day 0 (i.e., baseline), day 8 (i.e., immediately 1 h after exposure), and day 11 (i.e., 72 h following exposure) with f 2 frequencies ranging from 500 to 10,000 Hz and primaries L 1 and L 2 levels of 65 and 55 dB sound pressure level, respectively. Main effects were statistically found to be significant for group, time, and frequency (p�&lt;�0.05). DPOAE amplitudes were significantly larger for rabbits exposed to WBV, larger on day 8 and larger for mid to high f 2 frequencies (at and above 5,888.50 Hz). Main effects were not statistically found to be significant for ear (p�&gt;�0.05). Also, four statistically significant interactions including time by ear, time by frequency, group by frequency, and group by time were detected (p�&lt;�0.05). Contrary to the main hypothesis, DPOAE amplitudes were significantly larger for rabbits exposed to WBV. WBV exposure significantly led to enhanced mean A dp at mid to high frequencies rather than at low ones. © 2012 The Society for In Vitro Biology

Experimental and mathematical survey of sound absorption performance of date palm fibers

The present study examines the acoustic behavior sample composites made of date palm natural fibers and polyvinyl alcohol. It also provides the comparison between the sound absorption coefficients obtained from the experimental tests and the ones predicted by the mathematical models. An impedance tube system was used to measure the normal sound absorption coefficient of the samples. Using the differential equation algorithm, the predicted sound absorption coefficient for the Johnson-Champoux-Allard model was also calculated. The sound absorption properties of samples increased significantly by increasing the frequency, and increasing the thickness of materials with constant density. Comparison of the data from the experimental tests and mathematical model showed that increasing the thickness of samples will make the predicted and tested values of acoustic absorption coefficient significantly comparable. Date palm fibers have a good potential for dissipating the energy of sound waves particularly when an air gap is introduced behind the sample and can be used as a new source for the fabrication of natural fiber reinforced composites. © 2019 The Author(s

The role of a new electromagnetic shielding in reducing the microwave radiation for the X-band frequencies

Background and aims: X-band microwave with 8-12.5 frequency range has various applications such as air control traffic, navy communication etc. Uncontrolled exposure with microwave can lead to adverse effect on workers. Application of the shielding is superior control for prevention of microwave exposure. The aim of this study is production a new electromagnetic shielding for exposure control of X-band frequency by nano nickel oxide and epoxy resin. Methods: Nanocomposites prepared by epoxy resin and nano nickel oxide (7 wt) with 2, 4 and 6 mm thicknesses. Nanoparticles characterized by XRD and FESEM. Shielding effectiveness measured with vector network analyzer. Results: The Average of shielding effectiveness for three thicknesses were 2.68, 5.09 and 5.35 dB respectively that were equivalent to 45.98, 69.01 and 70.87 attenuation percentage. Maximum attenuation (8.96 dB or 87.29 attenuation percentage) obtained by the nanocomposite with 6mm thickness at 8.51 GHz frequency. The Average of shielding effectiveness increased with increasing the thickness. Conclusion: these nanocomposites could be used as appropriate shielding for exposure control of X-band frequency in workplace.Both Epoxy and nanocomposite with 6mm thicknesses are useful in specific frequency such as 8.52 and 8.51 GHz. However, According to economical and technical issues, nanocomposite with 4mm thickness is appropriate shield in this study. In according to required attenuation and economical benefit, attenuation matrix can be used for selecting the appropriate electromagnetic shield

Assessment of the influence of whole body vibration on Cochlear function

Background: Whole body vibration (WBV) is a potentially harmful consequence resulting from the dissipation of energy by industrial machineries. The result of WBV exposure on the auditory system remains unknown. The objective of the present research was to evaluate the influence of WBV on cochlear function, in particular outer hair cell function. It is hypothesized that WBV impairs cochlear function resulting in decreased Distortion Product Otoacoustic Emission (DPOAE) levels (Ldp) in rabbits subjected to WBV. Methods. Twelve rabbits were equally divided into vibration and control groups. Animals in vibration group were exposed to 1.0ms-2 r.m.s vertical WBV at 4-8Hz for 8h/day during 5 consecutive days. Outer hair cell function was assessed by comparing repeated-measurements of DPOAE levels (Ldp) across a range of f2 frequencies in rabbits both exposed and unexposed to WBV. DPOAE level shifts (LSdp) were compared across ears, frequencies, groups, and times. Results: No differences were seen over time in DPOAE levels in the non-exposed rabbits (p=0.082). Post-exposure Ldp in rabbits exposed to WBV were significantly increased at all test frequencies in both ears compared to baseline measures (p=0.021). The greatest increase in Ldp following exposure was seen at 5888.5Hz (mean shift=13.25dB). Post-exposure Ldp in rabbits exposed to WBV were not significantly different between the right and left ears (p=0.083). Conclusion: WBV impairs cochlear function resulting in increased DPOAE responses in rabbits exposed to WBV. DPOAE level shifts occurred over a wide range of frequencies following prolonged WBV in rabbits. © 2012 Moussavi-Najarkola et al.; licensee BioMed Central Ltd

Noise-induced outer hair cells' dysfunction and cochlear damage in rabbits

Background: Outer hair cells' (OHCs') dysfunctions as the extent of temporary and permanent threshold shifts (TTS and PTS) and cochlear damage were assessed in rabbits exposed to continuous noise. Methods: Twelve New Zealand white rabbits were studied in noise (N) (n=6; exposed to continuous noise; 95 dB SPL, 500-8000 Hz for 8 h per day during 5 consecutive days) and control (C) (n=6; not exposed to noise). OHCs' functions were assessed by distortion product otoacoustic emission (DPOAE) level (Ldp) measurements in different periods and comparing TTS and PTS. Animals were anaesthetized by CO2; cochleae were extracted, fixed in 10 formaldehyde for 48 hours, decalcified by 10 nitric acid for 24 hours, and dehydrated, embedded, sectioned 5 \am thickness and stained by Hematoxylin and Eosin for light microscopy. Results: The most and least Ldp or TTS or PTS were related to 5888.50 Hz and 588.00 Hz respectively in noise subjected rabbits (P0.05). Severely vacuolated OHCs, pyknotic IHCs, swollen SC, and slightly thickened BM were found. Conclusion: Continuous noise extensively led to OHCs' dysfunctions as decreased Ldp (both TTS and PTS) and highly damage to cochlea. © Iranian Red Crescent Medical Journal