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Biomedical subjects

I Yildiz

Publications and source records attributed to I Yildiz.

18 recordsLinked to original sources
PubMed2006

Synthesis, antimicrobial activity and QSARs of new benzoxazine-3-ones.

New ethyl 3,4-dihydro-3-oxo-4,6,7-trisubstituted-2H-1,4-benzoxazine-2-acetate derivatives were synthesized and their structures were elucidated by IR, (1)H NMR and mass spectral data. Antimicrobial activity of the compounds was investigated by using the method of twofold serial dilution technique against different Gram-positive, Gram-negative bacteria and some Candida species in comparison to standard drugs. Microbiological results indicated that the synthesized compounds possessed a broad spectrum of activity having MIC values of 6.25-100 micro g/ml against the tested microorganisms. The QSAR analysis of a set of these compounds tested for growth inhibitory activity against Candida krusei was performed by using the computer-assisted multiple regression procedure. The activity contributions for substituent effects of these compounds were determined from the correlation equation for predictions of the lead optimization.

Anti-Bacterial Agents↗
PubMed2006

Heterogeneity of damage between segments of rat liver after inflow-outflow obstruction.

BACKGROUND: Total vascular exclusion (TVE) causes warm liver ischemia. The complete explanation of the events during inflow and outflow obstruction of the liver during selective TVE has not yet been studied. The aim of this study was to investigate the liver injury caused by inflow-outflow obstruction in the rat liver. MATERIALS AND METHODS: Forty Wistar-Albino rats were divided into four groups. Liver inflow occlusion (groups A and C) or inflow-outflow occlusion (groups B and D) was applied for 30 minutes. Samples were collected at the end of the ischemia period. We examined oxidative injury in the liver tissue and liver histopathology. RESULTS: Oxidative stress and histopathologic alterations were more prominent with TVE application. Significant alterations were shown in hepatic superoxide dismutase, glutathione, and glutathione S-transferase levels. Central segments of the rat liver were affected significantly from inflow occlusion, whereas dome segments were significantly damaged from inflow-outflow occlusion. CONCLUSIONS: Inflow-outflow occlusion of the liver caused more tissue damage compared with inflow occlusion. The pattern of distribution of the damage due to TVE seemed different from other well-known ischemia-reperfusion injuries.

Animals↗
PubMed2006

3D-QSAR study on heterocyclic topoisomerase II inhibitors using CoMSIA.

Selective topoisomerase II (Topo II) inhibitors have interested to a great extent for the design of new antitumoral compounds in recent years. Comparative molecular similarity indices analysis (CoMSIA) was performed on a series of previously synthesized benzoxazole, benzimidazole, and oxazolo(4,5-b)pyridine derivatives as eukaryotic Topo II inhibitors. A training set of 16 heterocyclic compounds was used to establish the CoMSIA model. They were constructed and geometrically optimized using SYBYL v7.0. The predictive ability of the model was assessed using a test set of 7 compounds. The best model has demonstrated a good fit having r2 value of 0.968 and cross-validated coefficient q2 value as 0.562 including steric and hydrophobic fields. The hydrophobic interactions showed a dominant role for increasing Topo II inhibitor activity and hydrophilic substituent was found more important than hydrophobic one on the 5 or 6 position of benzazole moiety. The model obtained from the present study can be useful for the modification and/or evaluation of the development of new Topo II inhibitors as potential antitumor compounds.

Benzimidazoles↗
PubMed2006

A study on the antioxidant activities of some new benzazole derivatives.

The in vitro antioxidant properties of some new benzazole derivatives (1-10) such as benzoxazoles, benzimidazoles, and benzothiazoles were determined by their effects on the rat liver microsomal NADPH-dependent lipid peroxidation (LP) level, the scavenging of superoxide anion and the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Compounds 1, 2, 4 and 6, showed potent scavenging effect on superoxide radical at 10(-3) M. Compound 8, 5-nitro-2-(phenoxymethyl)benzimidazole, strongly inhibited lipid peroxidation at 10(-3) M concentration.

Animals↗
PubMed2004

Spectroscopic modification of the Pippard relation applied for the translational mode in ammonia solid II near the melting point.

This study gives our calculation for the frequency shifts 1v partial differentialv partial differentialT(P) and the specific heat C(P) near the melting point in the ammonia solid II. We establish a linear relationship between C(P) and 1v partial differentialv partial differentialT(P) using the Raman frequencies of the translational mode which we calculated in this system. This leads to the validity of the spectroscopic modification of the first Pippard relation in the ammonia solid II near the melting point. From this linear variation of C(P) with the 1v partial differentialv partial differentialT(P) we deduce the slope values of dP(m)dT near the melting point for the fixed pressures of 3.65, 5.02 and 6.57 kbar in the ammonia solid II. They are compared with the experimental dP(m)dT values for this system.

Ammonia↗
PubMed2004

Blue rubber bleb nevus syndrome associated with consumption coagulopathy: treatment with interferon.

The blue rubber bleb nevus syndrome (BRBNS) is a rare vascular malformation syndrome with cutaneous and visceral lesions frequently associated with serious, even fatal bleeding. No systemic therapy is currently available. We report here a case with disseminated skin and gastrointestinal venous malformations and findings of disseminated intravascular coagulation that was treated with interferon beta. The disseminated intravascular coagulation manifestations were cleared with the treatment. The regression of the coagulopathy in our patient led us to think that the use of interferon beta in BRBNS might be beneficial.

Child, Preschool↗
PubMed2000

Multidisciplinary approach to Wilms' tumor: 18 years of experience.

BACKGROUND: The aim was to evaluate the characteristics of Wilms' tumor and the results of combined modality treatment obtained in our center in Turkey. METHODS: From January 1978 to December 1996, 106 patients with Wilms' tumor were diagnosed. Of these 106 patients, 61 were male and 45 were female (M/F = 1,35); the median age at diagnosis was 39 months. The distribution of the 106 patients according to clinical stage was stage I 10%, stage II 42%, stage III 35%, stage IV 9% and stage V 4%. Histologically, 102 of the cases could be evaluated: favorable histology was diagnosed in 88.2% and unfavorable histology in 11.8% of the patients. Ninety-eight patients were treated according to NWTS and eight patients according to SIOP protocols. RESULTS: The EFS and overall survival rates at 2 years were 74.2 and 79.5% respectively, and at 5 years 72.4 and 76.6% respectively. CONCLUSION: As a developing country we evaluated our survival rates and report an improvement in treatment in recent years.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Tropisetron (Navoban) in the control of nausea and vomiting induced by combined cancer chemotherapy in children.

BACKGROUND: We aimed to assess the potency and efficacy of tropisetron, a 5-HT3 receptor antagonist, in the prevention of nausea and emesis observed in the pediatric patient population taking various chemotherapy protocols. METHODS: Tropisetron (Navoban) was given to 100 children (62 boys and 38 girls aged 6 months to 15 years) with various malignancies. Patients received tropisetron during one or more courses of emetogenic chemotherapy for a total of 350 courses administered intravenously or intravenously and intrathecally. Tropisetron (0.2 mg/kg/day, maximum: 5 mg/day) was administered as a single intravenous dose slowly, before the start of chemotherapy on day 1 and intravenously or by mouth on subsequent days (median treatment duration: 5 days). RESULTS: The patients receiving cytotoxic chemotherapy had a 70% complete response rate and a 24% partial response rate during the first 24 h period of the first course. We observed headache (five courses), diarrhea (three courses) and loss of appetite (one course) as side-effects (2.5%). CONCLUSION: Tropisetron is safe, effective, easy to use, has no serious side-effects and can be recommended for pediatric patients. The efficacy of tropisetron may be enhanced by the addition of corticosteroids in patients receiving highly emetogenic cancer chemotherapy.

Adolescent↗
PubMed1990

Pancreaticoduodenectomy. University experience and resident education.

A radical pancreaticoduodenectomy offers the best chance for survival in patients with periampullary and pancreatic malignant neoplasms. A pancreaticoduodenectomy has educational value since complex pancreatic operations are demanding and important to the training of surgical residents. Increased pancreaticoduodenectomy experience (per surgeon) has been associated with improved outcomes. We examined the hypothesis that residents who are supervised by faculty surgeons can perform pancreaticoduodenectomies with acceptable outcomes. From 1976 to 1987, 127 pancreatic resections were performed by 81 residents who were supervised by 15 faculty surgeons in four teaching hospitals. A pancreaticoduodenectomy was performed on 61 patients. All residents served as an operating surgeon on a pancreatic resection, and 58 (82%) performed pancreaticoduodenectomies. The mortality for the pancreaticoduodenectomies was 8%, with a 36% major complication rate. A pancreaticoduodenectomy can be performed safely by residents under supervision. A review of the results identifies the means of improving outcomes. These results justify the preservation of a pancreaticoduodenectomy as an important experience for residents.

Adult↗
PubMed1987

Small non-cleaved follicular center cell lymphoma in Turkey. Burkitt's and non-Burkitt's types. A retrospective clinicopathologic analysis of 53 cases in the pediatric age group.

Fifty-three patients in the pediatric age group diagnosed as having small non-cleaved follicular center cell (FCC) lymphoma (40 Burkitt's and 13 non-Burkitt's type) have been re-evaluated. Although the histopathologic distinction between the two subgroups is fairly easy to determine there is a considerable degree of clinical overlap in regard to age, sex, anatomic presentation of the disease, the incidence of bone marrow and central nervous system involvement, and the survival. The most important determinant of survival in both subgroups is the stage of the disease.

Adolescent↗
PubMed1987

Wilms' tumor: prognostic factors and survival.

A statistical analysis of 38 cases of Wilms' tumor treated and followed by the Pediatric Oncology Group of Cerrahpaşa Medical Faculty, from 1977 to 1984, is presented. The two-year survival rate was 67% and the five-year survival rate was found to be 63%. There was a strong correlation between the stage and age of the patients and prognosis. The median age was 16 months in stages I and II of the disease and the two-year survival rate was 87%. The median age was found to be 5 years in advanced stages and the survival rate at 2 years was 43%. No correlation was found between survival and initial symptoms of the tumor or its localization. The effects of histological grade on prognosis of disease were also investigated.

Adolescent↗
PubMedDate not supplied

Toxic epidermal necrolysis after the use of high-dose cytosine arabinoside.

We report a fatal case of toxic epidermal necrolysis (TEN) resulting from a high dose of cytosine arabinoside (ARA-C). A 13-year-old girl with acute lymphocytic leukemia was treated according to the protocol of the BFM Group (BFM-95, HRG). On the fifth day after administration of a high dose of ARA-C (2 g/m2 intravenously every 12 hours), she developed bullous lesions on the hands and soles that disseminated, evolving to necrosis, sepsis, and death on the 22nd day. ARA-C is frequently associated with dermatologic toxicity, but this is only the second case of toxic epidermal necrolysis described in connection with this drug.

Abdomen↗
PubMedDate not supplied

Regional DNA content heterogeneity in Wilms' tumor: incidence and potential clinical relevance.

DNA content (ploidy status and proliferative fraction) was retrospectively studied by flow cytometry on archival material from 44 Wilms' tumors of the kidney to evaluate intratumoral DNA heterogeneity and correlate the findings with clinicopathologic factors and patients' outcome. Analyses of 168 blocks from these neoplasms (average 4 per case) revealed diploid DNA in 24 (54.5%) and aneuploid DNA in 20 (45.5%). Thirteen (29.5%) Wilms' tumors demonstrated intratumoral DNA heterogeneity. No statistical correlation between DNA content and age, gender, tumor size, tumor stage, histological subtypes, and clinical outcome was found. Significant association, however, was found between DNA ploidy heterogeneity and unfavorable histology, and death due to disease. Our results indicate that approximately one third of Wilms' tumors manifest intratumoral heterogeneity and this accounts, at least in part, for the variable incidence of DNA ploidy reported and may be associated with pernicious biological feature.

Adolescent↗