Biomedical subjects
Publications and source records attributed to R Durmaz.
Nosocomial infection was found in 255 (2.5%) of 10,164 inpatients in a new medical center with a 310-bed capacity. The infection rate was 12.5% in the intensive care unit, 9.5% in neurology, 5.5% in general surgery, and 4.0% in orthopedics. Rates in the other services were lower. Hospital-acquired infections in our medical center frequently involved multiply resistant Enterobacteriaceae and staphylococci.
Twenty-eight rhodium, iridium or ruthenium complexes were evaluated for their in vitro antifungal activities against Candida albicans and Candida tropicalis. Fourteen compounds showed an antifungal activity against C. albicans and C. tropicalis with a range of the minimum inhibitor concentrations (MICs) between 16 and 250 micrograms/mL.
BACKGROUND: The aim is to determine the mechanism of non-hindbrain-related syringomyelia in experimental models. The effects of obstruction of central canal and subarachnoid space on occurrence of cavities were discussed. METHODS: 31 Sprague-Dawley rats were used with eight (Group D) as a control. In 10 rats (Group A) 1.5 microl kaolin was microinjected into the dorsal columns and central gray matter of the spinal cord at the level of Th6-10. In 10 rats (Group B) 0.1 cc kaolin was injected into the subarachnoid space at the same level. In 3 rats (Group C), 1.5 microl kaolin was administered into both dorsal midline of the spinal cord and the subarachnoid space. RESULTS: In Group A, histological examination revealed cystic cavity and dilatation of the central canal in five rats; denuded ependymal line and multicystic formations in ependymal and periependymal areas in seven rats. In Group B, denuded ependymal line in three rats and microcystic formations in ependymal and periependymal areas in four rats were revealed. In Group C, there were microcystic formations in two rats and syrinx cavity in one rat. CONCLUSIONS: Developments leading to occurrence of cavities are focused on the central canal in all groups. These models indicate that the CSF-flow is from the subarachnoid space to the central canal leading to changes of cavities. In cases of obstruction of the subarachnoid space or the central canal, the occurrence of syrinx cavity initially is due to increased CSF (cerebrospinal fluid) pressure in the central canal. Flow changes in spinal cord is indicated by this study.
The presence of the cellular multidrug resistance (MDR1) gene and its product, P-glycoprotein (Pgp), is thought to be a mechanism for the failure of chemotherapy in cancer patients. Calcium channel blockers have been shown to sensitise cancer cells to anticancer drugs by reversing Pgp expression in cell lines. The interactions between anticancer drugs such as carmustine (BCNU), vincristine (VCR) and procarbazine (PCB) and calcium channel blockers such as nimodipine and verapamil on cultured cells of glioblastoma from eight patients were therefore tested. Pgp expression was examined immunohistochemically using C219 monoclonal antibody in cytospin preparation. The cytotoxicity of the drugs was screened using microculture tetrazolium assay. The cells from five patients showed positive immunoreaction for Pgp. Nimodipine showed growth-inhibitory activity against glioblastoma cells at a rate of 16.55-26.88% (P < 0.05), but a similar effect was not observed with verapamil. While antiproliferative effects of BCNU were around 20.91-45.09% (P < 0.05) on the cells from seven patients, VCR was the most effective agent in inhibition of cell growth at a rate of 26.43-48.47% (P < 0.05). The response of the cells from five patients to PCB was from 11.98 to 16.32% (P < 0.05). When used together, nimodipine further enriched cytotoxicity of the anticancer drugs up to 11.14-40.85% (P < 0.05) without relation to Pgp expression. In conclusion, the enhancement of cytotoxicity of anticancer drugs by nimodipine suggests that there might be a synergy between anticancer drugs and nimodipine in the inhibition of glioma cell growth.
The 21-aminosteroids (lazaroids) are a new family of steroid compounds that inhibit lipid peroxidation reactions. They are novel antioxidant agents, which have been shown to have antiproliferative properties on cancer cells and also are thought to prevent free radical-mediated blood-brain barrier damage. In order to understand the effect of lazaroids on glioma, we tested U-83836E and U-74389G at doses ranging between 0.1 100 m mM on primary cultures of glioblastoma multiforme from three patients, rat C6 glioma cell line, and 5 th subculture established from one of the patients. The effects of both compounds on cell proliferation were determined using 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay. U-83836E in the primary cultures was found to have 50% inhibitory concentrations (IC50 ) of 6.30, 6.75 and 6.50 m mM, respectively. The IC50 value of U-74389G was calculated as 91 m mM in only one of the patients. On C6 glioma cells, while the IC50 of U-83836E was 45 m mM, U-74389G showed no cytotoxic effect. On the 5 th subculture, U-83836E had an IC50 of 37.5 m mM, but the cytotoxic effects of U-74389G was less than in that of the primary culture. In conclusion, these compounds were found to be more cytotoxic in primary culture than the cell lines and there were also differences between their members in the inhibition of cell survival.
Twenty ruthenium (II) complexes (1-5) were evaluated for their in vitro antibacterial and antifungal activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Candida albicans and Candida tropicalis. Compounds 1d, 1e, 1h, 1i and 1j showed more pronounced antimicrobial activity against Gram-positive bacteria and fungi as compared to the nitrogen donor ruthenium complexes; hydrophobic substituents were significantly more effective. None of the compounds 1-5 exhibited antimicrobial activity against the Gram-negative strains Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853) with the concentrations ranging between 12.5 and 800 micrograms/ml.
The fact that meningioma shows at least a 2:1 predilection for women over men is considered to be due to endocrinological and paracrine regulation of the development of this tumour. The presence of receptors for the luteinizing hormone releasing hormone (LHRH) in gynaecological cancer permits the use of LHRH agonistic or antagonistic analogues with a direct effect or by the gonado-pituitary axis suppression in the treatment of these tumours. Therefore, the effect of LHRH on meningioma cells is tested in this study. Meningioma cells from three female patients were cultured and LHRH (50 ng/ml) was added to the growth medium daily, for fourteen days. At the end of this period the cells were counted by means of a Coulter Counter. The stimulating effects of LHRH on the increase of the amount of cells in the meningioma monolayer culture were 146% (p < 0.01), 134% (p < 0.05) and 141% (p < 0.05) of the control, respectively, for the three patients.
Azolium salts and neutral 2-aryl derivatives of benzimidazole, benzothiazole and benzoxazole were synthesized and compounds were identified by 1H and 13C NMR spectroscopy and microanalytical methods. In this work the salts 1 and the neutral compounds 2 were evaluated for their in vitro antimicrobial activity against standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Candida albicans and Candida tropicals. The compounds 1f, 1g, 1l, 1m, 1n, 2a, 2b, 2c, 2e, 2f showed antimicrobial activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Candida albicans and Candida tropicals, with minimum inhibitory concentrations (MICs) ranging between 50 to 200 mg/mL. Compounds 1f, 1g, 1l, lm, 2b, 2c showed the highest activity. Benzothiazolium and benzoxazolium salts were more active than 1,3-disubstituted benzimidazolium salts and neutral 2-substituted benzimidazole, benzothiazole and benzoxazole derivatives.
Rats were subjected to incomplete cerebral ischemia induced by occlusion of common carotid arteries for 30 min, and subsequent reperfusion for 15 min. The concentrations of reduced glutathione (GSH), malondialdehyde (MDA) and superoxide dismutase (SOD) activity were determined in the dorsal hippocampus in order to evaluate their changes during ischemia and reperfusion following ischemia. The depletion of GSH was observed during ischemia with a further depletion during post-ischemic reperfusion (P < 0.001), while a significant increase in SOD activity and MDA levels was found only after reperfusion following ischemia (P < 0.001). Animals in which ischemia was followed by reperfusion were treated with a non-competitive NMDA receptor antagonist, MK-801 (1 mg/kg, i.v.), and a radical scavenger, U-83836E (5 mg/kg, i.v.), prior to ischemia. Although a full recovery of GSH levels was not observed following MK-801 and U-83836E pretreatment as compared to control (P < 0.05), MK-801 was more potent than U-83836E in the partial protection of the GSH pool (P < 0.05 and P < 0.01, respectively). The rise in SOD activity and MDA level were brought close to those of control due to the effects of both MK-801 and U-83836E (P > 0.05). In conclusion, the tissue changes in GSH concentrations evoked by ischemia and reperfusion were partially prevented by the effects of both drugs, MK-801 having the greater effect. This suggests that the NMDA receptor activation may play a role in the generation of reactive oxygen species. On the other hand, the inhibition of lipid peroxidation brought about by both MK-801 or U-83836E suggests the therapeutic efficiency of these agents in ischemia/reperfusion injury.
In order to establish the etiological agents of anaerobic infections, 154 clinical specimens collected from patients with suspected anaerobic infection were cultured under both aerobic and anaerobic conditions. Bacteria were isolated from 111 (72%) of these specimens. Only aerobes were recovered from 48 (43%), only anaerobes from 31 (28%) and both aerobes and anaerobes from 32 (29%) of the 111 specimens. A total 83 anaerobic bacteria including Bacteroides fragilis group (28%), Porphyromonas (19%), Peptostreptococci (10%), Prevotella (17%), Clostridia (12%), Fusobacteria (10%), Veillonella (2%) and Eubacteria (2%) were identified. Anaerobes were most commonly isolated from peritoneal fluid followed by joint fluid, abscess and endometrial materials, blood, soft-tissue biopsy and draining material.
We present a 69 year old man with two simultaneous meningiomas in different compartment of neural axis, in both of which 22q13 locus is lost. Histologically the two tumours appeared to be different; meningotheliomatous and transitional with psammoma bodies, respectively. No numerical or structural chromosome abnormalities were seen in karyotype analysis of the cultured spinal and cranial meningioma samples. Since long arm structural aberrations and/or whole loss of chromosome 22 are frequently reported abnormalities of meningiomas, the tumours were also analysed by fluorescence in situ hybridisation (FISH) with different colour-labelled probes in respect to relevant chromosome. The metaphases and interphase nuclei of the samples were evaluated by the combined biotinylated 22q11 and digoxigenin-labelled 22q13 locus specific FISH probes, and 22q13 deletion was revealed in both of spinal and cranial tumour cells. In conclusion, since both tumours from the presented case show the same genetic alterations, multiplicity may be derived from the same clone of cells, and support the theory of development of multiple meningiomas from the spreading of tumour cells via cerebrospinal fluid as a possible mechanism.
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To investigate whether Epstein-Barr virus (EBV) is associated with ordinary gastric carcinoma and to determine its genotype, samples from ordinary gastric carcinoma from 65 patients (40 males, 20 females) and 21 endoscopic biopsies from 7 individuals with non-neoplastic mucosa were analysed using one-stage and nested (two-stage) polymerase chain reaction (PCR) assays. The nested PCR assay yielded 56.9% (37/65) and 52.3% (11/21) positivity for the ordinary gastric carcinoma and control cases, respectively; these results were significantly than those of the one-stage PCR assay (13.5% and 0%, respectively). The EBV positivity showed similar rate in male and female patients (60% versus 52%, P > 0.05). The dominant genotype of EBV was 1 (92%) followed by mixture of 1 + 2 (5.4%) and 2 (2.6%). In conclusion, similar positivity rates of EBV in neoplastic and non-neoplastic tissues suggest that the relationship of this virus to the ordinary gastric carcinoma is not clear.
In order to determine the positivity rate and genotype of Epstein-Barr virus (EBV) in cases with Hodgkin's disease (HD) in Turkey, 40 tissue specimens from HD patients were analysed. Ten non-lymphoid tissue samples from individuals without any evidence for lymphoma were used as controls. The cases with HD included 33 males and 7 females with a mean age of 28 years. Nodular sclerosis was the most prevalent histological subtype (16/40) followed by mixed cellularity (10/40), lymphocyte predominance (9/40), and lymphocyte depletion (5/40). After histopathological evaluation, deparafinisation and lysis of the specimens, one-stage polymerase chain reaction (PCR) and two-stage (nested) PCR assays were performed with the primers common for both EBV genotypes and the primers specific for EBV types 1 and 2, respectively. EBV DNA was detected in 22 of 40 (55%) cases with HD and in 1 of 10 (10%) control specimens. The distribution of EBV DNA positivity according to the histological subtypes was as follows: 10 of 16 (62.5%) for nodular sclerosis, 3 of 5 (60%) for lymphocyte depletion, 5 of 9 (55.6%) for lymphocyte predominance, and 4 of 10 (40%) for mixed cellularity. Although most of the HD patients were males of 15-34 years of age, there were no significant differences between EBV positivities obtained from different sex and age groups. The rates of EBV genotypes were 82% for type 1, 9% for type 2, and 9% for both types, respectively.
Twenty-eight rhodium, iridium, or ruthenium complexes were evaluated for their in vitro antibacterial activity against Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922 and Pseudomonaa aeruginosa ATCC 27853. Ten compounds showed an antibacterial activity against Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 29213 with a range of the minimum inhibitory concentrations (MICs) between 16 and 125 micrograms/ml. None of the compounds exhibited antimicrobial activity against the gram-negative strains E. coli ATCC 25922 or Pseudomonas aeruginosa ATCC 29213 with a concentration range between 4 and 500 micrograms/ml.
In previous studies many benzimidazole, imidazole and benzothiazole derivatives had been synthesized and their antimicrobial activities were tested in vitro conditions. Four of these compounds showed minimal inhibitory concentrations (MIC) of 5-25 micrograms/ml against standard strains and clinical isolates. In order to determine whether these four compounds can be used for therapeutic purpose, their serum MIC values and side effects on hepatic and renal functions were determined. Different concentrations of the compounds were tested on Wistar rats. Compound 1 was administered orally, intramuscularly and intravenously; compounds 2, 3 and 4 were given orally and intramuscularly. Blood samples were taken 4 and 24 h after administration of the compounds. Serum MIC values were investigated by bioassay and serum levels of biochemical parameters by autoanalyzer. None of the tested compounds showed antimicrobial activity at their serum concentrations. Although creatinine activity was found at normal levels in all experiments, compounds 1 and 2 caused a significant increase in blood urea nitrogen (BUN) level. The values of aspartate aminotransferase and/or alanine aminotransferase and/or alkaline phosphatase which are characteristic for liver function were generally found at high levels. According to these results, it can be concluded that the tested compounds caused damage in liver and biliary tracts without antimicrobial activity by their serum concentrations.
The purposes of this study were to determine the prevalence of Turkish isolates of methicillin-resistant Staphylococcus aureus (MRSA) in nosocomial and community infections and their antibiotic resistant patterns. The oxacillin disk diffusion method for the detection of methicillin resistance and the Kirby-Bauer disk diffusion for antibiotic susceptibility tests were used. A total 383 S. aureus strains were identified from different patients. The prevalence of methicillin resistance among S. aureus strains was 31.3% (120/383). The proportions of MRSA isolated from nosocomial and community infections were 26.4% (46/174) and 35.4% (74/209), respectively. The resistance rates of MRSA to other antibiotics were as follows: 71% resistant to erythromycin, 54% to clindamycin, 52% to gentamicin, 44.5% to trimethoprim-sulfamethoxazole and 36% to ciprofloxacin. No strain resistant to vancomycin was recorded in this study.