İsmail Karabulut

Effect of toluene on erythrocyte membrane stability under in vivo and in vitro conditions with assessment of oxidant/antioxidant status

Toluene, an organic solvent used widely in the industry, is highly lipophilic and accumulates in the cell membrane impeding transport through it. Its metabolites cause oxygen radical formation that react with unsaturated fatty acids and proteins in erythrocytes leading to lipid peroxidation and protein breakdown. In this study, we aimed to investigate the membrane stabilizing and the oxidative stress—inducing effects of toluene in human erythrocytes. Measurements of osmotic fragility, mean corpuscular volume (MCV), oxidative stress parameters and antioxidant enzyme activities were performed simultaneously both in individuals exposed to toluene professionally (in vivo) and human erythrocytes treated with toluene (in vitro). To measure osmotic fragility, erythrocytes were placed in NaCl solutions at various concentrations (0.1% [blank], 0.38%, 0.40%, 0.42%, 0.44%, 0.46%, 0.48% and 1% [stock]). Percentage of haemolysis in each solution was calculated with respect to the 100% haemolysis in the blank solution. The erythrocyte packs prepared at the day of the above-mentioned measurements were kept at —80°C until the time for determination of malonyldialdehyde and protein carbonyl levels, and catalase (CAT) and glutathione peroxidase activities as indicators of oxidative stress. Toluene increased oxidative stress parameters significantly both in vivo and in vitro; it also caused a significant decrease in the activities of antioxidant enzymes. Osmotic fragility was altered only in the case of in vitro exposure. In conclusion, toluene exposure resulted in increased lipid peroxidation and protein damage both in vivo and in vitro. Although, it is natural to expect increased osmotic fragility due to oxidative properties of toluene, its membrane-stabilizing effect overcame the oxidative properties leading to decreased osmotic fragility or preventing its deterioration in vitro and in vivo toluene exposures, respectively, in the present study.

The effects of oral carvacrol treatment against H2O2 induced injury on isolated pancreas islet cells of rats

Pancreatic islet transplantation is an alternative treatment of insulin replacement therapy in diabetes mellitus, but the islets are exposed to many chemical, mechanical damages, and oxidative stress before transplantation. Carvacrol is a well-known essential oil for its antioxidant, antimicrobial, antifungal and antiinflammatory properties. The aim of this study was to investigate the possible protective effects of carvacrol against H2O2 induced cellular injury on isolated pancreas islets. After carvacrol (20, 40 and 80 mg/kg/day) treatment, the pancreas islets were isolated by enzyme digestion. The isolated islets were incubated within 0, 150 and 300 µM H2O2 containing medium at +4°C for 15 min. Then, the islets were examined with fluorescein diacetate and propidium iodide mixture stains for viability. A number of islets were stored for lipid peroxidation, protein oxidation and DNA fragmentation analysis. The cell viability ratio of Carvacrol 20 mg/kg/day group was increased in comparison to control and vehicle (DMSO) groups. Additionally, carvacrol application protected the cells from lipid peroxidation and protein oxidation induced by H2O2. H2O2 caused tissue injury and DNA fragmentation. There was only one DNA fragmentation band from islet cells of 20 mg/kg/day carvacrol treated group, however there were more than one bands from control and DMSO groups. In conclusion, carvacrol treatment ameliorates islet cell injury induced by H2O2. However, the dose of carvacrol is important and our results suggest that 20 mg/kg/day dose is more effective than doses of 40 or 80 mg/kg/day.

Audiological findings in celiac disease.

Objective: Celiac disease (CD) is a gluten-triggered immune enteropathy caused by a genetic predisposition. Recent papers suggest that CD is increasingly recognized by extraintestinal findings. The aim of this study was to investigate the effect of CD on hearing pathway including the olivocochlear efferent system in children. Methods: Forty-one pediatric CD patients and 31 controls were included in the study. Both groups were evaluated with audiometry, tympanometry, transiently evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and contralateral suppression of the TEOAE. Results: The threshold at 250 Hz of the patients with CD was significantly higher (p < 0.05 in CD compared to control group, p < 0.0001). The signal to noise ratio (SNR) amplitudes in DPOAE testing and the SNR amplitudes with and without contralateral acoustic stimulus in TEOAE testing were significantly lower at 1,000 Hz in the CD compared to the control group. There was no significant difference between the CD and the control group regarding contralateral suppression amplitudes. Conclusion: CD seems to have an important impact on the auditory system, and results in an elevation of the thresholds at 250 Hz on audiometry and a decrease in the amplitudes of DPOAE and linear TEOAE at 1,000 Hz in children.

The effect of oral isotretinoin (13-cis retinoic acid) on hearing systems in patients with acne vulgaris: a prospective study.

Isotretinoin is widely used in the treatment of extensive and nodulocystic acne. The objective of this prospective study was to investigate whether oral isotretinoin could affect the hearing system. Thirty‐eight patients with acne vulgaris (76 ears) who were diagnosed and treated at the Department of Dermatology were included in the current study. Study evaluation visits were performed at baseline and at Weeks 1, 2 and 3. Pure‐tone averages (PTAs) of air conduction thresholds at 250 Hz (PTA1); 500, 1000, and 2000 Hz (PTA2); 4000, 8000, and 10, 000 Hz (PTA3); and 12, 500, 16, 000, 18, 000 and 20, 000 Hz (PTA4) for each ear were calculated separately. Assessment of the efficacy was based on the audiometric findings. Compared with pre‐treatment evaluation, the PTAs of patients were found to be significantly different at the first week for PTA2 (P = 0.033) and PTA3 (P = 0.001), at the second week for PTA1 (P = 0.036), and at the third week for PTA4 (P = 0.002). Our results suggest that the oral isotretinoin (13‐cis retinoic acid), which is a derivative of retinol (vitamin A), improved the hearing level of the patients in all audiometric frequencies in a short‐period follow‐up.

Impact of Multilevel Surgical Treatment on Mean Platelet Volume in Patients With Obstructive Sleep Apnea Syndrome.

Background and Objectives:Mean platelet volume (MPV) is a potential marker of platelet reactivity. Increased MPV levels are shown to be the predictor of cardiovascular diseases, hypertension, and stroke. Previous studies demonstrated increased MPV levels in patients with obstructive sleep apnea syndrome (OSAS). The aim of this study was to examine the impact of 1-stage multilevel surgical treatment on MPV levels in patients with OSAS. Methods:Preoperative and postoperative 6-month hematologic parameters as well as polysomnographic findings of 42 patients, who underwent 1-stage multilevel surgery for treatment of moderate or severe OSAS, were compared. Results:In the comparisons of preoperative and postoperative apnea-hypopnea index (AHI) and MPV values, statistically significant decreases were detected There was a significant positive correlation between the decrease in mean AHI and decrease in MPV levels. Conclusions:One-stage multilevel surgery targeting the obstruction at the retropalatal and tongue-base levels was found to be effective in decreasing AHI and MPV. Mean platelet volume may be a new index to indicate the success of OSAS surgery.