Search PubMed⌕ Search

Biomedical subjects

T Yilmaz

Publications and source records attributed to T Yilmaz.

44 records · Page 3Linked to original sources
PubMedDate not supplied

The value of elective neck dissection in treatment of cancer of the tongue.

PURPOSE: The "adequate" therapy of tongue cancer has not yet been determined. The authors report their experience with 58 N(0) patients to elucidate the role of elective neck dissection in surgical treatment of cancer of the tongue. MATERIALS AND METHODS: The files of 58 N(0) patients with tongue cancer were evaluated retrospectively. In every patient, partial glossectomy continuous with neck dissection was the mainstay of the treatment. TNM staging, intraoperative N staging, pathologically confirmed cervical lymph node metastases and their levels, and clinical outcomes (local and regional recurrences) were recorded. The sensitivity and specificity of intraoperative staging was determined. RESULTS: Fifty-four percent (31/58) of the patients presented as T(1), and 26% (15/58) as T(2). The overall occult metastasis rate was 29.3% (17/58). The occult metastasis rate for T(1) and T(2) lesions was 19.4% (6/31) and 26.7% (4/15), respectively. The sensitivity of intraoperative staging was 76.5%, and the specificity was 51.2%. CONCLUSIONS: The rate of occult metastasis to the neck is too high in all tongue cancer cases to take the risk of regional recurrence, and the surgeon can not solely depend on neck palpation for determination of neck metastasis. Radiologic investigations and fine-needle aspiration decrease, but never reduce to zero the rate of false-negative examination. There is an obvious indication for neck dissection, even in early cases.

Adult↗
PubMedDate not supplied

Bcl-2 and LMP1 expression in nasopharyngeal carcinomas.

In vitro studies of B-cells immortalized by Epstein-Barr Virus (EBV) have shown that B-cell leukemia/lymphoma-2 (bcl-2) protein expression is upregulated by the EBV-latency-associated antigen, latent membrane protein 1 (LMP1). The same phenomenon has also been observed in epithelial cells in vitro. However, such correlation between these 2 markers has not been shown in nasopharyngeal carcinoma (NPC), in which EBV infection is a well-known etiologic factor. This retrospective study examined 35 cases of undifferentiated NPC to answer the question of whether LMP1 and/or bcl-2 presence can be used as biomarkers at treatment response, as well as to see the relationship between bcl-2 and LMP in NPC. Of the 35 patients, 26 (74.3%) were bcl-2, and 10 (28.6%) were LMP1-positive. Although a significant correlation was observed between bcl-2 and LMP1 staining (P =.003), it appeared that bcl-2 expression could be independent of LMP1. Statistical analysis showed that cervical lymph node metastasis (P =.04) and cranial nerve involvement (P =.03) are the only variables that significantly affect patient survival. At this time, bcl-2 and LMP1 presence are not significant indicators of outcome; however, although they are not directly related to survival, expression of both bcl-2 and LMP1 was strongly correlated with cervical lymph node metastasis, which is a potent predictor of patient survival.

Adaptor Proteins, Signal Transducing↗
PubMedDate not supplied

The protective effects of melatonin, vitamin E and octreotide on retinal edema during ischemia-reperfusion in the guinea pig retina.

PURPOSE: The purpose of this study is to provide evidence that free radical damage is a component of retinal ischemia-reperfusion (I/R) injury, and to determine whether melatonin, vitamin E and octreotide can protect retina from this injury. METHODS: The right eyes of 50 male guinea pigs weighing 500-600 g were used. The animals were randomly assigned to group 1 (control), group 2 (I/R), group 3 (melatonin + I/R), group 4 (vitamin E + I/R) and group 5 (octreotide + I/R). Groups 3, 4 and 5 received four subcutaneous injections at six-hour intervals for total dosage of 10 mg/kg melatonin, 150 mg/kg vitamin E and 22 microg/kg octreotide respectively. The first dose of each substance was administered 5 minutes before retinal ischemia. Retinal ischemia was induced for 1.5 hours, then followed by reperfusion for 24 hours. Infections of all three substances were repeated at 6, 12 and 18 hours during reperfusion. The animals were killed at 24 hours of reperfusion. Sagittal sections of 4 microm were cut and stained with hematoxylin and eosin for light microscopic evaluation. The average thickness (edema) of the inner plexiform layer for each eye was measured in sagittal sections near the optic nerve and expressed in microns. RESULTS: The efficacy of each compound had the following relationships: melatonin>vitamin E>octreotide in preventing retinal damage by ischemia-reperfusion. The mean thickness of the inner plexiform layer was 13.3 +/- 0.8 microm, 25.9 +/- 2. 0 microm, 20.0 +/- 0. 7 microm, 21.6 +/- 0.7 microm, 23.9 +/- 0.8 microm respectively in the control, I/R, I/R plus melatonin, I/R plus vitamin E and I/R plus octreotide groups. The thickness of the inner plexiform layer in group 1 (control) was significantly less than the other groups (p<0.001). The inner plexiform layer was thicker in the I/R group than with I/R plus melatonin, I/R plus vitamin E and I/R plus octreotide (all p < 0.01). The inner plexiform layer was thicker in the I/R plus octreotide group than the I/R plus vitamin E and I.R plus melatonin groups both (p < 0.05). Compared to the I/R plus melatonin group, the inner plexiform layer was significantly thicker in the I/R plus vitamin E group (p < 0. 05). CONCLUSIONS: This study demonstrates a protective effect of melatonin, vitamin E and octreotide on the retina during retinal ischemia-reperfusion injury.

Animals↗
PubMedDate not supplied

Aprotinin reduces ischemia-reperfusion injury in the retina of guinea pigs.

PURPOSE: The aim of this study was investigate the role of aprotinin on retinal lipid peroxidation and histopathological changes during ischemia/reperfusion (I/R) of guinea pigs. METHODS: Three groups of seven pigmented guinea pigs each were formed: a control (group 1), ischemia/saline (group 2) and ischemia/aprotinin (group 3). One eye of each animal was selected for histopathological evaluation and the other for biochemical assay. Bilateral pressure-induced retinal ischemia was instigated for 90 min and was followed by 24 hours of reperfusion. Animals in the ischemia/aprotinin and ischemia/saline groups received either 20,000 KIU/kg of aprotinin or saline, repeated four times at 6-hour intervals, with the first dose administered 5 min prior to the ischemic insult. The animals were killed at 24 hours of reperfusion. Retinal malondialdehyde (MDA) levels and the thickness of the inner plexiform layers were measured. RESULTS: The level of MDA in group 1 was significantly (p<0.001) lower than the other groups. The mean MDA level in group 2 was significantly (p<0.01) higher than in group 3. The inner plexiform layer in group 1 was significantly (p<0.001) thinner than in the other groups. The mean thickness of the inner plexiform layer in group 2 was significantly (p<0.01) higher than in group 3. CONCLUSIONS: These data indicate that intraperitoneally administrated aprotinin has a protective effect against I/R injury in the retina of guinea pig as evidenced by reduced retinal MDA level and retinal thickness.

Animals↗
PubMedDate not supplied

Effects of melatonin, vitamin E and octreotide on lipid peroxidation during ischemia-reperfusion in the guinea pig retina.

PURPOSE: The purpose of this study is to provide evidence that free radical damage is a component of retinal ischemia-reperfusion (I/R) injury, and to determine whether melatonin, vitamin E and octreotide can protect the retina from this injury. METHODS: The right eyes of 50 male guinea pigs weighing 500-600 g were used. The animals were randomly assigned to group 1 (control), group 2 (I/R), group 3 (melatonin + I/R), group 4 (vitamin E + I/R) and group 5 (octreotide + I/R). Groups 3, 4 and 5 received four subcutaneous injections with a 6-h interval for a total daily dose of 10 mg/kg melatonin, 150 mg/kg vitamin E and 22 microg/kg octreotide. The first dose of each substance was administered 5 minutes before retinal ischemia, which was induced for 1.5 hours, followed by reperfusion for 24 hours. All three substances were repeated for 6, 12 and 18 hours during reperfusion. The animals were killed at 24 hours of reperfusion. Retinas were isolated and processed for the quantification of malondialdehyde (MDA). RESULTS: The compounds had the following relationships: melatonin more than vitamin E more than octreotide in preventing retinal damage by ischemia-reperfusion. All three gave significantprotection against the formation of MDA (10.4+/-2.3, 12.4+/-2.4, 13.9+/-1.5 nmol/100 mg tissue wet weight, respectively) compared to the control (3.7+/-1.3 nmol/100 mg tissue wet weight) and I/R groups (22.7+/-6.2 nmol/100 mg tissue wet weight). CONCLUSIONS: This study demonstrates the inhibitory effect of melatonin, vitamin E and octreotide on MDA levels during retinal ischemia-reperfusion injury.

Animals↗
PubMedDate not supplied

Effects of methylprednisolone pulse therapy on insulin injections in patients with insulin-dependent diabetes mellitus.

In this study we evaluated 31 insulin-dependent diabetes mellitus (IDDM) patients (ages 12.1 +/- 3.4 years, 18 males/13 females) who started on multiple subcutaneous insulin injections (MSII) within six weeks of diagnosis and achieved either complete (CR: no insulin requirement and near-normoglycemia for at least two weeks) or incomplete (ICR: minimum 50% decline in insulin requirement while maintaining near-normoglycemia for two weeks or more) remissions within the first 12 weeks of the MSII trial. Methylprednisolone pulse therapy (MP) was administered four times per day by i.v. bolus at a dose of 30 mg/kg (max. 1000 mg) on alternative days. Eleven patients did not accept "MP-pulse" therapy; therefore, we followed these cases (7 males/4 females) as the control group. During the first year of follow-up, 13 patients from the "MP pulse" group achieved CR (3 males/1 female) or ICR (5 males/4 females) in 3.5 to 14 months. Remission occurred in only two of the control group cases (1 male CR for 17 days and 1 female CR for 7 months). Of those with CR in the "MP-pulse" and control groups, all were greater than 12 years of age, and all but one in the "MP-pulse" group were males. The stimulation capacity of beta cells (as defined by percentage increase in serum C-peptide levels after glucagon injection) among CR cases was found to be higher than that of non-remitted (NR) cases (p < 0.05 at onset, p < 0.001 during MSII-induced remission and p < 0.05 at the end of the first year of follow-up). Although patients with CR or ICR had higher beta cell reserves than NR cases at onset, only CR cases could sustain this capacity during the MSII-induced remission phase and one year after "MP-pulse" therapy. From this preliminary study, we conclude that "MP-pulse" therapy, may lead to prolonged near-normal beta cell function or partly preserved residual beta cell reserve during the MSII-induced remission phase of IDDM, The beneficial effects of MP could be seen clearly in patients diagnosed during the late childhood years.

Adolescent↗