Yazar "Karatas, E" seçeneğine göre listele

Listeleniyor 1 - 6 / 6
  • Küçük Resim Yok
    Öğe
    Aminoguanidine prevents ototoxicity induced by cisplatin in rats
    (Assoc Clinical Scientists, 2005) Iraz, M; Kalcioglu, MT; Kizilay, A; Karatas, E
    Cisplatin (CDDP) is one of the most potent antineoplastic drugs, but its therapeutic use is limited by side effects such as ototoxicity. This study tested the effect of aminoguanidine (AG), a specific inhibitor of inducible nitric oxide synthase, on CDDP ototoxicity. Female Wistar albino rats were randomly assigned to 4 groups: saline controls (n=7), CDDP (n=7), CDDP plus AG (n=7), and AG (n=7). Rats in the CDDP group received a single injection of cisplatin (16 mg/kg, ip). Rats in the CDDP plus AG group received aminoguanidine (20 mg/kg, ip) twice daily on the day before and on 5 consecutive days after a single injection of CDDP (16 mg/kg, ip). Rats in the AG group received aminoguanidine (20 mg/kg, ip) twice daily for 6 days. Distortion product otoacoustic emissions (DPOAEs) were elicited from the control and experimental animals utilizing a standard commercial otoacoustic emissions apparatus. DPOAEs were measured in the rats on day 0, prior to any drug administration, and on day 5. The initial baseline distortion product diagrams (DPgram) and input/output (I/O) function measurements gave similar results in all 4 groups. On day 5, there was significant deterioration of the DPgrams and I/O functions in the CDDP group; no significant changes of DPgrams and I/O functions were observed on day 5 in the other 3 groups. The median amplitudes of DPgrams and I/O functions revealed significant differences between the CDDP group and the other 3 groups. These results suggest that AG had a preventive effect against CDDP ototoxicity. In summary, this study indicates that AG prevents the cochlear dysfunction and hearing loss induced in rats by a single dose of CDDP.
  • Küçük Resim Yok
    Öğe
    The effects of the chorda tympani damage on submandibular glands: biometric changes
    (Elsevier Sci Ltd, 2003) Miman, MC; Sigirci, A; Ozturan, O; Karatas, E; Erdem, T
    Objective: It was aimed to analyze the biometric changes in ipsilateral submandibular glands of patients with unilateral chorda tympani (ChT) section during otological operations, compared with change in size of the contralateral glands and with those of healthy subjects. Method: 29 patients with unilateral complete ChT section and 29 healthy subjects with identical ages, genders, and weights to the patient group were examined ultrasonographically. The patients having a mean duration to follow-up examination of 32 months (2-84 months) were subdivided into two groups by their time to follow-up as short-term patient group (2-12 months. 14 patients) and long-term patient group (13-84 months. 15 patients). The ultrasonographic dimensions and volumes of submandibular glands were compared statistically between the groups. Results: In the patient group. the glands on the contralateral, non-operated side were found to be greater than the ipsilateral. denervated glands in terms of both paramandibular depth dimension (P <0.05) and volume (P <0.01). The differences could be determined only in long-term patient group. When comparing the submandibular glands of the patient group with those of the control group, it was found that paramandibular depth dimension and volume of the submandibular g-lands on the contralateral, non-operated side were statistically greater (P <0.01). There was no difference between submandibular glands on the operated side of the patient group and those of the control group (P >0.05). Conclusion: The late (13-84 months) biometric results of ChT damage on submandibular gland were significant for increase in the size of the contralateral, non-denervated submandibular gland. An atrophying effect was not ascertained in the submandibular glands denervated parasympathetically due to the section of the ChT. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Effects of the chorda tympani damage on submandibular glands: scintigraphic changes
    (Cambridge Univ Press, 2004) Yagmur, C; Miman, MC; Karatas, E; Akarcay, M; Erdem, T; Ozturan, O
    The aim of this study is to compare the scintigraphic results of a denervated submandibular gland with the contralateral normal side in patients with unilateral chorda tympani damage. Sixteen patients (11 women and five men with a mean age of 27) with unilateral proven chorda tympani damage during their previous ear surgery were included in the study. The perfusion ratio (PR), concentration ratio (CR) and stimulated excretion ratio (SER) were calculated scintigraphically and the results from the salivary glands on opposite sides were compared. For submandibular glands, the perfusion ratio (PR), concentration ratio (CR) and stimulated excretion ratio (SER) were found to be 0.65 +/- 0.21, 0.70 +/- 0.21, 0.79 +/- 0.37, respectively. All ratios resulted from statistically decreased radioactivity accumulation on the affected side (P<0.05). Chorda tympani damage negatively affects the function of the ipsilateral submandibular glands despite the absence of atrophy. Dynamic salivary gland scintigraphy is a practical and valuable method of disclosing the decreased capacity of perfusion, concentration and secretion function in unilateral neurological deprivation.
  • Küçük Resim Yok
    Öğe
    Exploration of the early auditory effects of hyperlipoproteinemia and diabetes mellitus using otoacoustic emissions
    (Springer-Verlag, 2003) Erdem, T; Ozturan, O; Miman, MC; Ozturk, C; Karatas, E
    Although the relationship between hearing loss and hyperlipoproteinemia (HLP) or diabetes mellitus (DM) has been shown in many clinical investigations, this concept is still controversial. A prospective study was designed to search for the existence of subclinical auditory dysfunction related to HLP and DM by transient-evoked (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs) in patients with hearing levels better than 30 dB. Evoked otoacoustic emissions were utilized to investigate subclinical auditory dysfunction. Fifteen hypercholesterolemic patients (28 ears), 21 hypertriglyceridemic patients (42 ears) and 21 DM patients (40 ears) were eligible for investigation. The results of the DPOAEs and TEOAEs of the study groups were compared with the control group composed of individuals with similar ages and with normal blood lipids and glycemia. This group consisted of 22 people (44 ears). There was no difference in the existence of TEOAEs at all frequencies among the groups (P>0.05). No differences were found in the amplitudes of the DPOAES between the groups except at 4 kHz (P>0.05). The difference was caused by the hypertriglyceridemia group (P=0.014) and the non-insulin-dependent diabetes mellitus (NIDDM) group (P=0.012) when compared with the control group. The mean DPOAE amplitudes of the hypertriglyceridemic and NIDDM groups at 4 kHz were higher, than those of the control group. The decreased DPOAE amplitudes at 4 kHz in hypertriglyceridemic and diabetic patients without clinical findings are compatible with the sensorineural hearing loss observed with hyperviscosity and increased noise susceptibility, as was shown before in these patients. Longitudinal investigations should be performed with otoacoustic emissions to help with the early prediction of the prospective effects of HLP and DM on the auditory system.
  • Küçük Resim Yok
    Öğe
    Management of cerebrospinal fluid gusher in pediatric cochlear implantation
    (Royal belgıan soc ear, nose, throat, head & neck surgery, po box 1248, leuven, 00000, belgıum, 2018) Karatas, E
    Management of cerebrospinal fluid gusher in pediatric cochlear implantation. Objectives: This study's aim is to evaluate the management of Cerebrospinal Fluid (CSF) gusher after cochlear implantation in children postoperatively. Methodology: 120 children (age ranges 13 to 72 months) who underwent cochlear implantation and eight of them had CSF gusher intraoperatively. Successful cochlear implantations and intraoperative management performed by complete packing of the electrode around in cochleostomy with muscle for Case I to III. CSF gusher was observed in these cases postoperatively. Second and third look revision surgeries were performed. Also, fat tissue was used for the sealing of leakage in Case IV to VIII. Results: Severe CSF gusher occurred in 6 children with the common cavity, moderate in one child with Incomplete Partition (IP) type 1 and mild in one child with normal cochlea. Sealing the cochleostomy with muscle performed in the first 3 children intraoperatively and they also had CSF gusher postoperatively. Revision surgeries were performed for 3 children. Sealing the cochleostomy with fat tissue was successful in Case I and II but not in Case III. Subtotal petrosectomy and obliteration of cavity with fat tissue had been performed for Case III. CSF leakage has not been seen in the other 5 children with fat tissue packing for the postoperative long term. Conclusions: CSF gusher may occur in pediatric cochlear implantation with inner ear malformations postoperatively. Packing around the electrode in cochleostomy with muscle may not be enough. Fat tissue packing is more effective than muscle for the postoperative long term.
  • Küçük Resim Yok
    Öğe
    The protective effect of erdosteine against ototoxicity induced by cisplatin in rats
    (Springer, 2005) Kalcioglu, MT; Kizilay, A; Gulec, M; Karatas, E; Iraz, M; Akyol, O; Egri, M
    The elimination of cisplatin ototoxicity is an ongoing concern. This experimental study was undertaken to investigate the effect of oral erdosteine in ameliorating cisplatin-induced ototoxicity. Twenty-eight adult female Wistar albino rats were randomly divided into four equal groups. Group A received an oral carrier vehicle of the drug erdosteine with 0.2 ml of 0.9% saline. Group B was administered only erdosteine (per oral 10 mg/kg twice a day) for 6 days. Group C was injected with cisplatin intraperitoneally (i.p.) on day 0 (16 mg/kg body weight), once only. Group D was given erdosteine (per oral 10 mg/kg/day) 1 day before and for 5 days consecutively after cisplatin injection (16 mg/kg, i.p.). Distortion product otoacoustic emissions (DPOAEs) were elicited in different frequency regions, ranging from 1,001 to 6,299 Hz as DPgram and input/output (I/O) functions from the control and experimental animals. All experimental animals were killed under general anesthesia on day 5, following the last otoacoustic emission measurements. Prior to death, blood samples were drawn for measurement of superoxide dismutase, xanthine oxidase (XO), malondialdehyde and nitric oxide. Initial DPgram and I/O function baseline measurements were similar in all groups prior to any drug administration ( P > 0.05). On day 5, intra-subject measurement parameters of DPgrams and I/O functions in the cisplatin group showed significant deterioration ( P < 0.05). The other groups revealed no differences between their pre- and post-test drug administration DPgrams and I/O functions at any test frequency ( P > 0.05). Comparison of the amplitudes of DPgrams and I/O functions between the cisplatin and control groups showed significant changes ( P < 0.05). Biochemical studies noted an increased XO activity following cisplatin administration ( P < 0.007). The other biochemical results did not show significant differences between the study and control groups. This study demonstrates that, in rats, erdosteine is protective for cochlear function against the disruptive effects of cisplatin as measured by DPOAEs.