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Biomedical subjects

O Yildiz

Publications and source records attributed to O Yildiz.

At least 19 recordsLinked to original sources
PubMed2006

Leptin, soluble interleukin-6 receptor, C-reactive protein and soluble vascular cell adhesion molecule-1 levels in human coronary atherosclerotic plaque.

The aim of the present study was to explore the relationship between tissue levels of leptin, soluble interleukin-6 receptor (sIL-6R), high-sensitive-C-reactive protein (hs-CRP) and soluble vascular cell adhesion molecule-1 (sVCAM-1) in atherosclerotic plaques, and traditional risk factors. Coronary artery specimens were obtained from 35 consecutive patients (26 men and nine women) who underwent coronary artery bypass grafting procedure. The mean tissue levels of leptin, hs-CRP and sIL-6R were significantly higher in patients with diabetes mellitus than without diabetes mellitus. When patients were classified according to the smoking status, the mean tissue levels of leptin, hs-CRP and sIL-6R were significantly higher in current smokers than both former smokers and non-smokers. In addition, the mean tissue levels of leptin and sIL-6R were significantly higher in former smokers than non-smokers. There was a positive association between leptin and hs-CRP, sIL-6R and plasma glucose in all patients. Plasma HDL levels were associated negatively with atherosclerotic tissue levels of leptin. Tissue levels of sIL-6R were associated significantly in a positive manner with leptin, hs-CRP and plasma glucose, while tissue levels of hs-CRP were associated with both leptin and sIL-6R. In conclusion, it is attractive to speculate that hs-CRP, sIL-6R and leptin could act synergistically in course of local inflammatory activity and those molecules may not be just markers of inflammation and cardiovascular risk but are also likely to play a pathogenic role in atheromatous plaque. In addition, atherosclerotic tissue levels of CRP, sIL-6R and leptin were significantly higher in current smokers and patients with diabetes.

Aged↗
PubMed2005

1,25-Dihydroxy vitamin D3: can it be an effective therapeutic option for aggressive fibromatosis.

Aggressive fibromatosis (AF), also known as desmoid tumor is a monoclonal fibroblastic proliferation in a collagen matrix that arises in musculoaponeurotic structures. Though considered as benign, they are locally invasive and their propensity for recurrence after conservative surgery is well documented. Addition of postoperative adjuvant radiotherapy produces higher local control rates, although recurrence rates are still high in patients with positive margins. The antineoplastic activity of vitamin D has been demonstrated both in vitro and in vivo models of several cancers. The proposed mechanisms for antineoplastic activity include inhibition of proliferation associated with cell cycle arrest, induction of apoptosis and reduction in invasiveness and angiogenesis. It has also been shown that vitamin D has a negative impact on collagen homeostasis by inhibiting the formation and increasing its degradation. Since vitamin D has an antineoplastic activity and negative effect on collagen synthesis and deposition, it is proposed that 1,25-dihydroxy vitamin D3 can be a right therapeutic option for the management of desmoid tumors.

Antineoplastic Agents↗
PubMed2005

Importance of timing of antiaggregant treatment in the prevention of radiation induced enteropathy.

Chronic radiation enteropathy (CRE) is an undesirable radiation-induced toxicity and a common health problem in patients with pelvic or abdominal malignancies. Damage to microvascular endothelial cells and connective tissue is blamed to cause this adverse effect. It is shown that platelets are the first cellular elements that initiate the homeostatic and inflammatory responses and release of several proinflammatory and fibrinogenic mediators. Antiplatelet agents such as ticlopidine and clopidogrel were shown to prevent CRE and this effect is believed to be directed by their activities against thrombocytes. However, recent studies have shown that these drugs also induce apoptosis in endothelial cells and may lead to decreased expression of endothelial prostacyclin and thrombomodulin (TM) and increased release of von Willebrand factor which are shown to be major contributors of coagulation process. Assuming that radiation induced apoptosis occur 6-10h after irradiation, we think that timing of these antiaggregant drugs with irradiation is important and a 6-10h interval between these may be beneficial to avoid this adverse interaction.

Apoptosis↗
PubMed2005

Nocardiosis in a teaching hospital in the Central Anatolia region of Turkey: treatment and outcome.

Predisposing factors, antimicrobial susceptibility patterns, treatment and outcome were analysed for nine consecutive patients with nocardiosis. Predisposing factors were identified in six (67%) of the nine patients. Clinical syndromes of nocardial infection were pulmonary infection (three patients), cerebral infection (five patients) and disseminated infection (one patient). The predominant (60%) species was Nocardia farcinica rather than the Nocardia asteroides complex. Treatment was started empirically, modified according to the antimicrobial susceptibility pattern, and then continued for 6-12 months. Overall mortality was 33%, with death being caused by the Nocardia infection in two cases.

Adult↗
PubMed2004

Nocardia brain abscess mimicking brain tumour in immunocompetent patients: report of two cases and review of the literature.

Nocardia brain abscess is a rare intracranial lesion and has been reported in immunocompromised patients. An optimal treatment approach has not been established. However, early diagnosis and appropriate antimicrobial therapy are very important factors for a good outcome. We report two unusual cases of Nocardia brain abscess simulating brain tumour in immunocompetent patients. One of the cases was presumed to be a primary brain tumour and the other a metastatic brain tumour. They underwent surgical gross total resection. After Nocardia asteroides was seen on Gram's stain and subsequently identified by culture, appropriate antibiotic therapy was initiated.

Adolescent↗
PubMed2004

Effects of azithromycin on cyclosporine-induced gingival hyperplasia in renal transplant patients.

BACKGROUND: Gingival hyperplasia is a well-known complication of cyclosporine therapy, affecting 21% to 35% of renal transplant patients. Metronidazole, clarithromycin, and azithromycin, all azalid antimicrobial agents derived from the macrolide antibiotic erythromycin, have been used for treatment. Marked improvements in gingival hyperplasia have been recorded in particular with azithromycin. The aim of the present study was to investigate histopathological features of cyclosporine-induced gingival hyperplasia and to evaluate the quantitative efficacy of short-term azithromycin therapy. METHODS: Eighteen renal transplant patients with cyclosporine-induced gingival hyperplasia were included in the study. All patients received azithromycin with a dose of 500 mg/d for 3 consecutive days. Changes in gingival hyperplasia were evaluated by measuring the gingival sulcus depth to the cementum-enamel junction of every tooth in each of the four quadrants on days 0, 7, 30, 90, 180. Gum biopsies were obtained on days 0 and 30; the degree of inflammation was classified as "mild," "intermediate," and "severe". RESULTS: Gingival hyperplasia was reduced in all treated patients throughout the study. The degree of improvement was more significant between 0 to 7 and 7 to 30 days than at other times (respectively, P < .0001 and P < .002). Histopathologically, eight patients had severe and one patient moderate chronic inflammation at the beginning of therapy. Three other biopsies were reported as papilloma, mucosal hyperplasia, and normal gingival tissue biopsy. CONCLUSIONS: Azithromycin appears to be useful to treat cyclosporine-induced gingival hyperplasia in renal transplant patients. Treatment is inexpensive and free from known adverse effects.

Adult↗
PubMed2003

The importance of serial measurements of cytokine levels for the evaluation of their role in pathogenesis in familial Mediterraean fever.

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent fever of unknown origin, renal amyloidosis, peritonitis, pleuritis and/or synovitis. There have been many studies to elucidate the etiopathogenesis of FMF. IL-6 is a cytokine that can induce the formation of serum amyloid A and C-reactive protein, both of which are important in development of amyloidosis. IL-6 was determined to be strongly associated in the etiopathogenesis of periodic fever in Chinese-pei dogs. The dogs with this syndrome experience periodic fever, arthritis, renal amyloidosis, a clinical picture very alike of human FMF. Here, we aimed to study mainly whether IL-6 had a similar etiopathogenetic role in human FMF as in Chinese-pei dogs syndrome. The median IL-6 blood levels were found to be higher in patients with acute (n=8) FMF attack (1.85 U/ml) compared to those (n=33) with asymptomatic ones (1.0 U/ml) (p=0.16). There are mainly two results: first; the study should be designed with a larger sample size of patients with acute attack in order to alleviate underestimation of significance, second; sampling time may give various results because of dynamic changes of cytokine levels during acute attack period.

Adolescent↗
PubMed2002

Polymicrobial ventriculitis and evaluation of an outbreak in a surgical intensive care unit due to inadequate sterilization.

At the end of 1999, a case of polymicrobial ventriculitis in the Department of Neurosurgery followed by an outbreak of Serratia marcescens mediastinitis in the intensive care unit of cardiovascular surgery occurred. These nosocomial surgical infections were considered to be the result of contamination of surgical sites with inadequately sterilized instruments or theatre linen. An epidemiological survey was focused on the central sterilization unit of the hospital. The microbiological results of this survey proved that the cause of the outbreak was the use of inadequately decontaminated theatre linen. This study indicates that strict infection control measures including the control of sterilization procedures and a well-organized infection control team are necessary to prevent nosocomial surgical infections.

Acinetobacter Infections↗
PubMed2000

Phenylephrine precontraction increases the sensitivity of rabbit femoral artery to serotonin by enabling 5-HT1-like receptors.

We used selective receptor antagonists to identify the receptors mediating the isometric contractile response to serotonin in control and phenylephrine (PHE)-precontracted rabbit femoral artery rings. Serotonin, in the absence of PHE, elicited monophasic concentration-response curves (CRCs) early, but biphasic CRCs late in the course of the study. In the monophasic curves, the threshold and maximal concentrations were 10 and 1,000 microM, respectively. In biphasic CRCs, the threshold and maximal concentrations of the first phase were 0.03 and 3 microM, respectively. The respective values for the second phase were 10 and 1,000 microM. Prazosin, 0.1 microM, a selective alpha1-adrenoceptor antagonist, inhibited the monophasic curves, but only the second phase of the biphasic curves. Ritanserin, 0.01 microM, a selective 5-HT2A-receptor antagonist, shifted the first phase of the biphasic serotonin CRCs to the right but had little effect on the second phase. PHE increased the sensitivity of rabbit femoral artery response to serotonin. This amplified response to serotonin was antagonized by 0.01 microM GR 127935T, a selective 5-HT1B-receptor antagonist. The selective 5-HT1 agonist, sumatriptan, had no effect in control femoral arteries, but caused a concentration-dependent contraction after PHE precontraction. These results suggest that 5-HT1-like receptors are normally inactive or "silent" in the absence of PHE. However, in the presence of PHE, these receptors become enabled and mediate the amplified response to serotonin. The evidence also suggests that, in the absence of PHE, alpha1-adrenoceptors mediated the contractile response to serotonin in the monophasic CRCs. In the biphasic curves observed late in the study, the first phase was mediated by 5-HT2A receptors, and the second, by the alpha1-adrenergic receptors.

Animals↗
PubMed1999

Beneficial effect of thyrotropin-releasing hormone on neuropathy in diabetic rats.

Thyrotropin releasing hormone (TRH) is therapeutically effective in experimental and clinical spinal injury. The effects of TRH on diabetic neuropathy are not known. The aim of the present study was to investigate the electrophysiological effects of TRH in the streptozotocin diabetic rats. Three groups of rats were studied, non-diabetic control (n = 10), diabetic controls (n = 8), and TRH treated diabetic rats (n = 9). Administration of TRH or saline and electrophysiological measurements were performed 4 weeks after induction of diabetes. TRH was given intraperitoneally in a dose of 600 microg (3 ml). Nerve conduction velocity (NCV), measured in caudal nerve, and N1 latency of somatosensory evoked potentials (SEP) were measured 75 min after injection of TRH or serum saline. SEP latencies were 28.1 +/- 0.6, 29.4 +/- 0.8, 27.8 +/- 1.1 ms, in normal, diabetic and diabetic TRH-treated groups, and NCV values were 28.1 +/- 0.8, 23.8 +/- 0.4, and 27.9 +/- 0.7 m/s respectively. NCV was significantly reduced in the diabetic group compared to normals (P < 0.05). but then improved by TRH treatment (P < 0.05). Our findings suggest that TRH has an acute effect on peripheral neuropathy in experimental streptozotocin diabetes in the rat.

Animals↗
PubMed1999

Acetyl salicylic acid improves somatosensory evoked potentials in streptozotocin-diabetic rats.

The effects of acetyl salicyclic acid (ASA) on somatosensory evoked potentials (SEP) and neural levels of thiobarbituric acid reactive substances (TBARS), products of lipid peroxidation, were studied in streptozotocin-diabetic rats. ASA (100 mg/kg, in rat chow) was given to diabetic rats (n = 8) after the induction of diabetes for 16 weeks. ASA-treated normal control rats (n = 8), untreated diabetic rats (n = 8) and normal control rats (n = 8) were used for comparison. At the 8 weeks, SEP latency in diabetic group (15.4 +/- 0.5 ms) was significantly longer than that in normal control group (10.0 +/- 0.8 ms, P < 0.05). When compared to levels in diabetic control group, ASA shortened SEP latency significantly (12.7 +/- 0.1 ms; P < 0.05). This effect of ASA was significant in all three measurements from week 8 to 16 (P < 0.05 vs. diabetic control group). Neural TBARS level in diabetic control group (60.1 +/- 2.2 nmol/g) was significantly, higher than that in normal control group (28.5 +/- 3.6 nmol/g, P < 0.05). When compared to levels in diabetic control group, ASA depressed TBARS level significantly (41.5 +/- 12 nmol/g; P < 0.05). TBARS level in ASA-treated diabetic group (27.2 +/- 5.7 nmol/g) was comparable with that in normal control group (NS). These results suggest that ASA has beneficial effect on diabetic neuropathy and this effect may be related in part with prevention of lipid peroxidation.

Animals↗
PubMed1999

The clinical value of the ratio of free prostate specific antigen to total prostate specific antigen.

OBJECTIVE: To examine the usefulness of the ratio of free prostate specific antigen (FPSA) to total prostate specific antigen (TPSA) in men with serum TPSA concentration of 4 to 10 ng/mL by using the cut off value of 0.15 for avoiding unnecessary biopsies. PATIENTS AND METHODS: Two hundred thirty-six men aged between 52 and 91 with symptoms of prostatism were evaluated with digital rectal examination (DRE), FPSA and TPSA measurements. Patients with TPSA values under 4 ng/mL were biopsied if they had positive DRE and/or a FPSA/TPSA ratio lower than 0.15. All patients with TPSA values higher than 4 ng/mL were also biopsied. The predictive value and sensitivity of FPSA/TPSA ratio and TPSA alone were calculated. RESULTS: Eleven patients out of 170 with a TPSA value lower than 4 ng/mL were biopsied. Fifty-five patients had a value between 4.1 and 10 ng/mL. We performed transrectal ultrasound (TRUS) and prostate biopsy in these men except one patient. Biopsy proven prostate cancer was detected only in 12 patients. In this group of patients the predictive value of TPSA was 21%, but the predictive value of FPSA/TPSA ratio of 0.15 was 78% maintaining at least 90% sensitivity. Eleven of the patients had a prostate specific antigen (PSA) value higher than 10 ng/mL. In 6 of these patients the biopsy result was prostate cancer and 10 of these patients had a FPSA/TPSA ratio lower than 0.15. CONCLUSION: In patients with TPSA values between 4-10 ng/mL the cut off value of FPSA/TPSA ratio of 0.15 can be used to eliminate unnecessary biopsies with minimal loss of cancer patients.

Aged↗
PubMed1998

Relationship between prostate specific antigen density, microvessel density and prostatic volume in benign prostatic hyperplasia and advanced prostatic carcinoma.

The aim of this study was to investigate the relationship between prostate specific antigen density and prostate volume with microvessel density in patients with benign prostatic hyperplasia and advanced prostatic carcinoma. Sixty-eight patients with benign prostatic hyperplasia and 11 patients with advanced prostatic carcinoma participated in the study. The paraffin blocks of all patients were stained with CD34 by the standard immunohistochemical technique and microvessel density, prostate specific antigen density and prostatic volume were determined. In patients with benign prostatic hyperplasia the mean microvessel density, mean prostate specific antigen density and mean prostatic volume were 74+/-89+/-22.73, 0.12+/-0.10 and 59.97+/-27.0 ml, respectively. There was no correlation between prostate specific antigen density and mean prostatic volume or microvessel density (r = 0.079 and -0.095, respectively). In patients with advanced prostatic carcinoma the mean microvessel density, mean prostate specific antigen density and mean prostatic volume were 147.90+/-47.55, 0.63+/-0.41 and 54.00+/-22.42 ml, respectively. In this group, while there was a good correlation between prostate specific antigen density and microvessel density (r = 0.785), no significant correlation was found between prostatic volume and microvessel density (r = -0.07). There was significant statistical difference in patients with advanced prostatic carcinoma compared to patients with benign prostatic hyperplasia in terms of mean microvessel density (p<0.0001). The findings that there was no correlation between prostatic volume and MVD either in benign prostatic hyperplasia or in prostatic carcinoma suggest that microvessel development is not correlated with prostatic volume but may be correlated with morphology.

Aged↗
PubMed1998

Serotonin and vasoconstrictor synergism.

Contractile synergism between serotonin (5-hydroxytryptamine, 5-HT) and other vasoconstrictor substances has been observed in a number of peripheral and cerebrovascular blood vessels. This phenomenon may play an important role in certain pathological states such as hypertension, peripheral vascular disease, and coronary spasm. In the present review, we summarize studies on the synergism between serotonin and other vasoconstrictor agents and focus on a recently described type of vasoconstrictor synergism in which precontraction with a non-5-HT receptor agonist yields an enhanced contractile response to serotonin which is mediated by previously inactive or "silent" 5-HT receptor subtypes.

Animals↗
PubMed1998

Establishment and characterization of a human glioblastoma multiforme cell line.

Cell lines provide a useful system for further understanding the biology of glioblastoma multiforme. In this study, a new glioblastoma multiforme cell line, GATAGM-96 (Gulhane Askeri Tip Akademisi-Gliblastoma Multiforme-96), was established from a tumor specimen removed from an 80-year-old male patient who underwent surgery for intracranial tumor. Morphologic examination, immunocytochemical staining, growth kinetics, and karyotypic characteristics of this cell line were studied. The cytoskeleton was positive for neuron-specific enolase, vimentin, and neurofilament, and it was negative for glial fibrillary acidic protein, S-100 protein, p53 protein, epidermal growth factor, and transforming growth factor alpha. Growth kinetic studies demonstrated an approximate population doubling time of 38 to 42 h and a colony forming efficiency of 83.3%. The karyotype of the cells demonstrated it as hyperdiploid, with a large subpopulation of polyploid cells. There were numerous structural and numerical chromosome aberrations; most of them were present as clonal events. The phenotypic and chromosomal features detailed on the GATAGM-96 cell line should make it a useful addition to the cell lines currently available for in vitro and in vivo studies of glioblastoma multiforme.

Aged↗
PubMed1996

L-carnitine treatment improves brain stem auditory evoked potentials in diabetic rats.

The effect of L-carnitine (LC) on brain stem auditory evoked potentials (BAEP), was examined in alloxan-diabetic rats. LC (200 mg kg-1, i.p., once daily) was given to diabetic rats starting from the third week after the induction of diabetes, lasting for 4 weeks. Age-matched non-diabetic rats served as controls. The latency of wave I and interpeak latency I-IV were measured once weekly. Diabetes-induced deficits in BAEP latencies (p < 0.05, diabetics vs non-diabetic controls) were improved after LC treatment (p < 0.05, LC-treated diabetic rats vs non-diabetic controls). Weight and glucose levels were not influenced by LC treatment. Our results suggest that LC had beneficial effects on diabetic central neuropathy but these effects are not associated with the regulation of glycaemia in alloxan-diabetic rats.

Animals↗