The protective effect of metformin against the noise-induced hearing loss.

OBJECTIVE: To test the protective effect of metformin against noise-induced hearing loss. METHODS: 24 rats were included in the study. The first group was exposed to noise only, the second group took metformin, the third group was exposed to noise and took metformin, and the fourth group was neither exposed to noise nor took metformin as control group. After measurement of baseline DPOAE and ABR of rats, the metformin group and the metformin + noise group received 300 mg/kg/day metformin via gavage for 10 days. On the 11th day, group 1 and group 3 were exposured to white noise at 105 dB SPL for 15 h. After noise exposure, DPOAE and ABR measurements of all rats were repeated on days 1st, 7th, and 21st. At the end of the study, all animals were sacrificed and cochlear tissues were separated for immunohistochemical assessments. RESULTS: ABR threshold values and DPAOE measurements of groups 1 and 3 were deteriorated on the 1st day after noise, while deterioration in group 1 continued on 7th and 21st days, but normalized on 7th day in group 3. After immune staining, a significant immunoreaction was observed in the noise group, while the reaction in the noise + metformin group was close to the control group. CONCLUSION: Metformin has a protective effect on noise-induced hearing loss in rats. As a conclusion, it is determined that metformin protects from permanent threshold shift in rats. It can be considered a good alternative for protecting noise-induced hearing loss.

Comparison between corneal cross-linking, topical antibiotic and combined therapy in experimental bacterial keratitis model.

PURPOSE: This study was conducted to investigate the effects of an experimental bacterial keratitis model on the corneal collagen cross-linking treatment (CXL), and also to compare topical antibiotic treatment with the combined treatment. METHODS: The study involved 40 young adult female Sprague Dawley rats, which had a 2 mm scraped defect of the central corneal epithelium in both eyes. The rats were divided into two equal groups. The first group was inoculated in both eyes with standard Pseudomonas Aeruginosa (PA) from a strain suspension prepared from 0.05 ml (Group 1), and the second group was inoculated with standard Methicillin Resistance Staphylococcus Aureus (MRSA) strains from a suspension prepared from 0.05 ml (Group 2). Group 1 was divided into four sub-groups: Group 1A was treated by collagen cross-linking (CXL), Group 1C was treated with topical tobramycin drops CXL and also treated by collagen cross-linking (CXL), Group 1D was treated with topical tobramycin drops, and Group 1B was left untreated in order to create a control group. Similarly, Group 2 was also divided into four sub-groups: Group 2A was treated by CXL, Group 2C was treated with topical 5% fortified vancomycin drops CXL and also treated by CXL, Group 2D was treated with topical 5% fortified vancomycin drops, and Group 2B was left untreated in order to create a control group. CXL was performed on the third day following the inoculation and topical drop therapy. Biomicroscopy and microbiologic assessments were performed on the third and seventh days following the inoculation of microorganisms. RESULTS: In the treatment, which compared baselines in all groups before treatment, the diameter of keratitis infiltrations, corneal clouding, and corneal swab samples were obtained from the reduction in reproduction. The results were statistically significant (p < 0.01). Keratitis infiltration groups were conducted on the seventh day for Groups 1C and 1D according to Group 1B, whilst Groups 2A, 2C and 2D were conducted according to Group 2B, which showed a significant statistical reduction (p < 0.01). On the seventh day, focal groups were conducted in corneal clouding Group 1D according to Group 1B and in Groups 2A, 2C and 2D according to Group 2B, which revealed a significant statistical reduction (p < 0.01). On the seventh day, reproduction in culture was obtained from corneal swab samples in Groups 1C and 1D according to Group 1B; in Groups 1C and 1D according to Group 1A; in Groups 2A, 2C and 2D according to Group 2B; and in Group 2C according to Group 2A, where a significant statistical reduction was observed (p < 0.01). CONCLUSIONS: The clinical and microbiological efficacy of the CXL treatment is evaluated in our study. In accordance with the conclusion reached an effective reduction in the density and severity of (infection), occurred as a result of CXL treatment, CXL treatment combined with topical antibiotic treatment and topical antibiotic treatment of Pseudomonas Aeruginosa (PA) and Metisilin Rezistant Staphylococcus Aureus (MRSA) keratitis infections. From these results, it is shown that topical antibiotics and CXL potentiate each other's effects in the treatment of resistant bacterial keratitis.

Effect of melatonin on cytokine levels in a hyperthermia-induced febrile seizure model.

Higher serum cytokine levels have been reported in children admitted with febrile seizures and in some experimental models. However, other studies have shown that cytokine levels are influenced by melatonin. In this study, we investigated serum cytokine levels in a hyperthermia-induced febrile rat seizure model and the effect of melatonin. A total of 28 male Sprague-Dawley rats were divided into four groups: the control (C) group, healthy melatonin (MT) group, and hyperthermia-induced febrile seizure groups with (HIFS-MT) and without (HIFS) administration of melatonin. Melatonin (80 mg/kg) was given intraperitoneally 15 min before the seizure. HIFS was induced by placing the rats in 45°C water. The rats were sacrificed under anesthesia after the seizure. Blood samples were drawn by transcardiac puncture to measure serum cytokine and melatonin levels. Serum interleukin (IL)-1ß, IL-6, IL-10, and tumor necrosis factor (TNF)-α levels were lower in the HIFS group than those in the C group (p = 0.005, p = 0.200, p = 0.011, and p = 0.016, respectively). All serum cytokine levels of rats in the MT and HIFS-MT groups were similar to those in the C group. This experimental rat model demonstrated that serum cytokine levels decrease with HIFS and that administering melatonin maintains serum cytokine levels. These results suggest that cytokines may play role in the anticonvulsive activity of melatonin in rats with febrile seizures.

[The relationship between passive rhinomanometry measurements in sitting and supine position and obstructive sleep apnea syndrome]. / Oturur ve sirtüstü pozisyonda pasif rinomanometri ölçümleri ve tikayici uyku apne sendromu ile iliskisi.

OBJECTIVES: This study aims to investigate the possible relationship between passive rhinomanometry measurements in sitting and supine position and obstructive sleep apnea syndrome. PATIENTS AND METHODS: Between January 2011 and December 2013, 88 male patients (mean age 46.8 years; range 18 to 79 years) underwent passive rhinomanometry in sitting and supine position following history, physical examination and fiberoptic endoscopic examination. 1.5 lt/sn air flow was pumped into the nose of each patient via a silicone nasal mask. Meanwhile, flow and pressure values were measured. RESULTS: There was no correlation between the resistance values and apnea hypopnea index (AHI) scores and polysomnography and physical examination parameters (p>0.05). The differential resistance was correlated with AHI (r=0.325, p<0.05), body mass index (r=0.324, p<0.05), neck circumference (r=0.421, p<0.01), waist circumference (r=0.444, p<0.01), modified Mallampati score (r=0.356, p<0.05), and retropalatal grade (r=0.438, p<0.01). CONCLUSION: The correlation between the differential resistance and physical examination parameters and AHI scores support the hypothesis that position-related retropalatal segment alterations can be measured by passive rhinomanometry while awake.

Effect of Er,Cr:YSGG laser irradiation on apical sealing ability of calcium silicatecontaining endodontic materials in root-end cavities.

The aim of this research was to evaluate the apical sealing abilities of 60 root-end cavities filled with mineral trioxide aggregate (MTA) and iRoot BP cements after treated with either 17% EDTA solution or Er,Cr:YSGG laser irradiation. After the filling procedure, apical leakage quantity was measured at 4 weeks using a fluid filtration method. One root from each group was processed for scanning electron microscopy and energy dispersive X-ray spectroscopy analyses. Both EDTA/MTA and laser irradiation/MTA combinations showed significantly lower microleakage than EDTA/iRoot BP and laser irradiation/iRoot BP combinations (p<0.05). Between groups of the same filling material, there were no significant differences among specimens treated with EDTA or laser (p>0.05). Both MTA and iRoot-BP demonstrated tag-like structures within the dentinal tubules when used in conjunction with EDTA.

Minocycline treatment inhibits lipid peroxidation, preserves spinal cord ultrastructure, and improves functional outcome after traumatic spinal cord injury in the rat.

STUDY DESIGN: A prospective, randomized experimental research. OBJECTIVE: To evaluate the short- and long-term neuroprotective effects of minocycline on the secondary injury process of an experimental traumatic spinal cord injury (SCI) model. SUMMARY OF BACKGROUND DATA: Traumatic SCI is a devastating problem of health that results in high morbidity and mortality rates. The loss of function after SCI results from both the primary mechanical insult and the subsequent, multifaceted secondary response. METHODS: A total of 80 adult male Spraque-Dawley rats (breeded by the Baskent University Animal Research Center) were randomly divided into 4 groups. A T10 contusion injury was produced by using modified Allen technique in all groups except the control group. No medication was administered to the rats in the trauma group. Minocycline was administered intraperitoneally and intravenously to the treatment groups. Short-term and/or long-term neuroprotective effects of minocycline on the lipid peroxidation (malondialdehyde, glutathione), apoptosis (terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling), ultrastructure of spinal cord (tissue electron microscopy), and behavioral assessments (Basso-Beattie-Bresnahan) were evaluated. RESULTS: As compared with the trauma group, tissue malondialdehyde and glutathione levels demonstrated that minocycline significantly diminishes lipid peroxidation. Electromicroscopic study showed that minocycline preserves the ultrastructure of spinal cord tissue in the early post-traumatic period. Minocycline treatment significantly reduced the number of terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling positive cells both 1 day and 28 days after SCI. Behavioral assessments showed significant improvement in the hind limb functions of minocycline receiving rats starting 7 days after the SCI. Any statistically significant difference was not found between intraperitoneal or intravenous routes for minocycline injection. CONCLUSION: Minocycline is neuroprotective and contributes to functional improvement after traumatic SCI by eliminating the destructive process of secondary injury. Having both satisfying anti-inflammatory and antiapoptotic effects in experimental models, it promises to be of therapeutic use in human SCI.

Proinflammatory and anti-inflammatory cytokines in gingival crevicular fluid and serum of patients with rheumatoid arthritis and patients with chronic periodontitis.

BACKGROUND: The aim of this study is to evaluate proinflammatory and anti-inflammatory cytokine levels in gingival crevicular fluid (GCF) and serum of rheumatoid arthritis (RA) and chronic periodontitis (CP) patients to assess whether cytokine profiles distinguish patients with RA and patients with CP while using healthy patients as background controls. METHODS: A total of 49 patients, 17 patients with RA (three males and 14 females; mean age: 47.82 ± 10.74 years), 16 patients with CP (10 males and six females; mean age: 44.00 ± 7.00 years), and 16 controls (eight males and eight females; mean age: 28.06 ± 6.18 years) were enrolled. Patients with RA were under the supervision of rheumatologists; 15 of the patients with RA were being treated with methotrexate-sulfasalazine combined therapy, and two of the patients were being treated with leflunomid therapy. Periodontal parameters (plaque index, gingival index, probing depth, and clinical attachment level) were recorded. Interleukin (IL)-1ß, IL-4, IL-10, and tumor necrosis factor-α (TNF-α) were determined in GCF and IL-1ß and IL-10 in serum by enzyme-linked immunosorbent assay. RESULTS: There were significant differences found among RA, CP, and control groups for all periodontal parameters (P <0.05). The total amount and concentration of GCF IL-1 ß, IL-4, IL-10, and TNF-α were similar in RA and CP patients (P >0.05). Although the total amount and concentration of serum IL-10 was not significantly different among the groups (P >0.05), serum IL-1ß was significantly lower in the RA group compared to CP patients and controls and was higher in GCF of the RA group compared to the CP group. CONCLUSIONS: Although clinical periodontal disease parameters indicated more severe periodontal disease in CP compared to RA patients, immunologic evaluation did not reveal consistent results regarding proinflammatory and anti-inflammatory cytokine levels. This might be a result of the use of non-steroidal anti-inflammatory drugs and rheumatoid agents by patients with RA.

Risks of metabolic syndrome in students of the faculty of health sciences.

BACKGROUND: Metabolic syndrome is highly prevalent in the adult population worldwide. Education may play an important role in preventing metabolic syndrome in young adults, especially those who are attending university. Such adults are at a critical point in their lives and make their own lifestyle choices that can affect their future health. AIMS: The aims of this study were to determine the metabolic syndrome risk levels of students from the Faculty of Health Sciences. STUDY DESIGN: Survey design study. METHODS: In a questionnaire developed by the researchers to collect data in accordance with the relevant literature, the scale of the risk of metabolic syndrome was assessed. A stepwise logistic regression analysis was performed to determine the risks. RESULTS: Important risk factors for metabolic syndrome were found to be gender, weight gain, "stress eating" excessive amounts of food, sleeping for more than 8 hours a day, feeling tired after sleep, belonging to a divided family, and eating whilst working on the computer. CONCLUSION: The students from the Faculty of Health Sciences, particularly because they are trained in the health sector, are expected to have more information about the risk factors of metabolic syndrome, and take necessary precautions to prevent it.

Increased vulnerability to oxidative stress in pediatric migraine patients.

Little is known about the role of oxidative stress in the pathogenesis of pediatric migraine. The objective of the present study was to investigate, during a headache-free period, the activities of erythrocyte antioxidant enzymes in children and adolescents diagnosed with migraine. In all, 47 migraine patients (age range, 8-17 years; mean, 14.1 +/- 2.4 years, 14 with aura) and 35 control subjects were included. Superoxide dismutase, glutathione peroxidase, and catalase activities were measured in erythrocytes. Although superoxide dismutase activities did not differ between groups, both catalase and glutathione peroxidase activities were significantly lower in migraine patients (P = 0.001 and P = 0.009, respectively). Activities of all three antioxidant enzymes were similar across migraine subgroups; there was no correlation with age and sex. These results confirm vulnerability to oxidative stress in pediatric migraine. Further studies and search for new therapeutic agents with antioxidant properties are needed.

Push-out bond strength and SEM evaluation of new polymeric root canal fillings.

OBJECTIVE: The objective of this study was to compare the interfacial strengths and failure modes of new polymeric endodontic obturation systems consisting of different material combinations. STUDY DESIGN: Extracted human single-rooted teeth (n = 105) were instrumented using HERO Shaper rotary instruments and obturated with different combinations of core and sealer as follows: group 1, RealSeal/Resilon; group 2, RealSeal/Herofill; group 3, Hybrid Root Seal/Resilon; group 4, Hybrid Root Seal/Herofill; group 5, MM-Seal/Resilon; group 6, MM-Seal/Herofill; group 7 (control). Failure modes of root slices (1.00 +/- 0.05-mm thick) after push-out testing were examined with stereomicroscope and scanning electron microscopy. RESULTS: Hybrid Root Seal/Resilon combination had significantly greater bond strength than all the other groups (P < .001); RealSeal/Resilon combination proved to have the second highest bond strength (P < .001). Bond failure was mainly mixed failure in both adhesive and cohesive modes at the dentin/sealer interface. CONCLUSION: The push-out bond strengths of methacrylate-based sealers (Hybrid Root Seal and RealSeal) and thermoplastic synthetic-polymer-based core material (Resilon) combinations were higher than epoxy-resin-based sealer (MM-Seal) and gutta-percha (Herofill) combination.

Elevated CK-MB mass and plasma brain-type natriuretic peptide concentrations following convulsive seizures in children and adolescents: possible evidence of subtle cardiac dysfunction.

PURPOSE: To evaluate the presence of myocardial injury during convulsive seizures in children and adolescents by determining serum concentrations of cardiac troponin I (cTnI), creatine kinase-MB mass (CK-MB mass), and plasma brain-type natriuretic peptide (BNP). METHODS: Thirty-one children (20 boys; mean age, 6.6 +/- 5.34 years) with convulsive seizures and 50 healthy children were enrolled. Serum cTnI, CK-MB mass, and plasma BNP concentrations were analyzed 12 h after the seizure and repeated 7 days thereafter in the patient group and obtained one time in the control group. RESULTS: The difference between serum concentrations of cTnI obtained 12 h and 7 days after the seizure was not statistically significant. cTnI levels 12 h postictal and those in control subjects also were not significantly different. CK-MB mass and BNP at the 12th h were higher than those obtained on the 7th day (p < 0.05 and p < 0.001, respectively). Children with seizures had increased levels of CK-MB mass and BNP 12 h after seizure than control subjects (p < 0.05 and p < 0.001, respectively). The results of electrocardiography (ECG) recordings, which were obtained up to 30 min after seizure activity, were completely normal in patients with seizure. CONCLUSION: Normal cTnI levels are not indicative of overt myocardial necrosis in patients with seizures. However, markedly elevated BNP concentrations together with elevated CK-MB mass levels do suggest subtle cardiac dysfunction in patients with seizure, and further large-scale studies are warranted.

Clinical and radiographic evaluations of chitosan gel in periodontal intraosseous defects: a pilot study.

Periodontitis is a chronic infection in the supportive tissue of the teeth which eventually leads to tooth loss. Various grafting materials and barrier membranes have been used to repair periodontal intraosseous lesions. Chitosan is a derivative of chitin, a natural biopolymer, which is biologically safe, biodegradable, and nontoxic and has been applied in a variety of forms in dentistry. It also exerts bioactive properties such as wound healing, antimicrobial, tissue regeneration, and hemostatic activities. The aim of this study was to evaluate effects of chitosan on periodontal regeneration. Twenty chronic periodontitis patients were recruited. Following initial therapy, the patients were divided into four groups: group A, receiving chitosan gel (1% w/v); group B, receiving chitosan gel + demineralize bone matrix; group C: receiving chitosan gel + collagenous membrane; and group D, receiving flap only (control group). Clinical and radiographic measurements were recorded at baseline, day 90 (3rd month), and day 180 (6th month) after surgery. For clinical data, no significant differences were obtained among the treatment groups. However, radiographic data revealed that except control group, all the other groups showed statistically significant bone fills when compared with baseline indicating that chitosan gel alone or its combination with demineralize bone matrix/collagenous membrane is promising for periodontal regeneration.

Plasminogen activator inhibitor-1 gene 4G/5G polymorphism in Turkish children with asthma and allergic rhinitis.

Plasminogen activator inhibitor (PAI-1) has an essential role in tissue remodeling after inflammation. Recent literature revealed only one study evaluating PAI-1 4G/5G gene polymorphism in children with asthma and none in children with allergic rhinitis. We aimed to investigate distribution of PAI-1 4G/5G polymorphism in a group of Turkish children with asthma and allergic rhinitis and compare these findings with those obtained in normal peers. Patients with physician-diagnosed asthma (n = 106) and allergic rhinitis (n = 99) and 83 healthy peers were included in this study. We evaluated PAI-1 4G/5G polymorphism genotype as well as the possible association between PAI-1 4G/5G polymorphism and pulmonary function tests, serum total immunoglobulin E (IgE), total eosinophil count, and skin-prick test positivity in our study. The prevalence of the 4G allele significantly exceeded the values found in the controls both in patients with asthma (p = 0.001) and in patients with allergic rhinitis (p = 0.002). Interestingly, comparison of asthmatic patients revealed that mean baseline percent forced expiratory volume in 1 second and forced vital capacity were significantly higher in patients who bear 5G/5G genotype than in those who have 4G/4G or 4G/5G genotypes. No statistically significant relationship were found between PAI-1 polymorphism and total serum IgE levels, total eosinophil count, or selected skin test responses to aeroallergens. Our study suggests that Turkish children with asthma or allergic rhinitis have a higher prevalence of PAI-1 4G allele compared with their healthy peers.

Dental erosion in chronic renal failure.

Dental erosion is a common oral finding in chronic renal failure and may develop due to extrinsic and/or intrinsic causes. The aim of this study was to compare the salivary calcium and phosphorus levels, salivary flow rate, salivary buffer capacity, salivary pH, serum calcium and phosphorus levels and parathyroid hormone levels in chronic renal failure patients with and without dental erosion. Twenty-four men and 19 women who had had chronic renal failure for at least 2 years were studied. Twenty-two subjects displayed erosion-like patterns on their teeth and the other 21 patients showed no signs of erosion. Two closely age- and sex-matched control groups (control groups 1 and 2) were enrolled in this study because of the age disparity between the erosion and non-erosion groups. The data were analyzed by Mann-Whitney U test, Student t test, Pearson's and Spearman's correlation tests. None of the comparisons were statistically different between the erosion and non-erosion groups. There were statistically significant differences in salivary calcium (P < 0.01) and phosphorus (P < 0.01) levels, serum phosphorus level (P < 0.01) and serum PTH level (P < 0.01) for the erosion group and control group 1 and also for the non-erosion group and control group 2. There was also a significant difference in salivary flow rate (P < 0.05) for the erosion group and control group 1. There was a positive significant correlation between saliva buffer capacity and salivary phosphorus level (r = 0.454, P < 0.05) in the erosion group.

Ultrastructural examination of glomerular and tubular changes in renal allografts with cyclosporine toxicity.

The introduction of cyclosporine (CsA) has improved the clinical results of renal transplantation significantly; however, these improvements were closely associated with an increased incidence of renal dysfunction. The present study sought to examine the ultrastructural changes in renal allografts with CsA nephrotoxicity. Nine patients who underwent renal transplantation at the Baskent University Faculty of Medicine between 2001 and 2002 were examined; 26 biopsies of these nine patients who had received their first renal allograft were included in this study. All patients with CsA toxicity showed some form of glomerular endothelial cell injury. The swelling of mitochondria was present in three of nine renal allografts with CsA toxicity, and podocyte changes were found significantly more frequently among patients with CsA toxicity. In addition, focal segmental thickening and the duplication of glomerular basement membrane were observed statistically more frequently. In conclusion, these findings could help differentiate CsA toxicity from other conditions and develop better treatment strategies.

The effect of melatonin treatment on oxidative and nitrosative stress in rats with thioacetamide-induced hepatic damage.

BACKGROUND: : The following study aimed to clarify the importance of arginase and NOS activities in thioacetamide-induced hepatic damage and to evaluate the underlying mechanism of proposed protection provided by melatonin, using commonly applied therapeutic dose. METHODS: : Rats were randomly assigned to four groups (n=5): control, melatonin (10mg/kg i.p.), thioacetamide (200mg/kg i.p., two doses with a 24h interval) and thioacetamide+three doses of melatonin (10mg/kg i.p., prior- and post-treatment with a 24h interval before thioacetamide administrations) treated groups. RESULTS: : Thioacetamide administration caused hepatic damage creating oxidative and nitrosative stress accompanying perivenous necrosis and eosinophil infiltration. The significant elevation of total nitrite level in livers of thioacetamide treated groups reflected the activation of inducible nitric oxide synthase activity. The decrease in arginase activity indicated hepatic damage. Non-altered specific activity of arginase in the livers of thioacetamide treated groups did not overcome the elevation of NO production. Melatonin treatment did not modulate the levels/activities significantly. CONCLUSIONS: : Our results have indicated that nitrosative stress seems to be essentially critical in thioacetamide-induced hepatic failure in rats. Possible regulatory effect of arginase on NO production and applied dose of melatonin could not prevent hepatic damage.

Contractile responses of the human umbilical artery to KCl and serotonin in Ca-free medium and the effects of levcromakalim.

It is known that K(ATP) channel openers inhibit the release and refilling of Ca(2+) from intracellular stores. The present study was designed to test the effects of levcromakalim in human umbilical artery (HUA) rings stimulated by serotonin (5-HT) and KCl in Ca-free medium. Umbilical cords were obtained at vaginal or cesarean deliveries from healthy, term pregnancies. After the isolation, HUA rings were placed in organ baths in solution with indomethacin (10(-5) M) and N(G)-nitro-L-arginine methyl ester (L-NAME) (10(-3) M) at 37 degrees C and aerated with 95% O(2) and 5% CO(2) for the measurement of isometric force. In Ca-free solution with Ethylene glycol-bis (ss-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) (2 mM) the contractions produced by 5-HT (10(-6) M) and KCl (40 mM) decreased significantly. Afterwards, HUA rings were treated with 5-HT and KCl in repeated manner in Ca-free medium. In contrast to KCl, 5-HT induced contractions reduced in each application, progressively. Levcromakalim (10(-4) M) abolished the contractions elicited by 5-HT. On the other hand, levcromakalim had a little but significant inhibitory effect on KCl induced contraction in Ca-free medium. These results suggest that Ca(2+) is not the only transduction pathway in KCl produced contractions of HUA smooth muscle cells.