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Biomedical subjects

B Sener

Publications and source records attributed to B Sener.

At least 19 recordsLinked to original sources
PubMed2003

Chemical and antimicrobial properties of calcium hydroxide mixed with irrigating solutions.

AIM: Chemical and antimicrobial effects of paste-like suspensions of calcium hydroxide (Ca(OH)2) powder with chlorhexidine (CHx), sodium hypochlorite (NaOCl) or iodine potassium iodide (IPI) solutions were tested and compared to conventional Ca(OH)2/saline paste. METHODOLOGY: Equivalent mixtures of Ca(OH)2 with irrigating solutions were compared to conventional Ca(OH)2/saline paste for their ability to raise the pH in root dentine. Ca(OH)2 pastes were compacted into prepared root canals of single-rooted extracted human teeth. Changes in root pH over time were recorded with a microelectrode placed in standardized wells within root surfaces. Antimicrobial efficacy of test solutions and pastes against Enterococcus faecalis and Candida albicans was assayed using an agar diffusion test. RESULTS: The ability of Ca(OH)2 to raise the pH in the root dentine was maintained when using mixtures of Ca(OH)2 with CHx, NaOCl or IPI (Kruskal-Wallis, P > 0.05). Mixtures of Ca(OH)2 with the test solutions had similar antimicrobial properties as equivalent mixtures with saline (anova, P > 0.05). The efficacy of CHx was reduced when mixed with Ca(OH)2. No additive antiseptic effects were recorded between Ca(OH)2 and IPI or Ca(OH)2 and NaOCl. CONCLUSIONS: Ca(OH)2 is a strong alkali, whose pH is not changed when adding weak acids or alkalis in aqueous suspensions. Under the conditions of this study, mixing Ca(OH)2 powder with the test irrigating solutions did not provide an increased antimicrobial effect compared to a conventional Ca(OH)2/saline medication.

Analysis of Variance↗
PubMed2003

Interactions of ethylenediamine tetraacetic acid with sodium hypochlorite in aqueous solutions.

AIM: To evaluate interactions of ethylenediamine tetraacetic acid (EDTA) with sodium hypochlorite (NaOCl). METHODOLOGY: Solutions consisting of 8.5% EDTA and 0.5% NaOCl were compared to a 1 : 1 (w/w) mixture of 17% EDTA and 1% NaOCl for their calcium-chelating, tissue-dissolving, and antimicrobial properties. Amounts of available chlorine were determined in the EDTA/NaOCl solutions with an iodine/thiosulphate titration method. Calcium chelation capacity was titrated with a pure calcium solution using a murexide indicator. Weight loss of porcine palatal mucosal specimens incubated in the test solutions was measured over time. Antimicrobial potential of pure solutions and the combination was recorded using an agar diffusion test in plates incubated with Enterococcus faecalis or Candida albicans. RESULTS: The presence of hypochlorite had little effect on the calcium-chelating ability or on the antimicrobial potential of EDTA. Available chlorine content decreased to 0.06% in the combined EDTA-NaOCl solution compared to 0.50% in an equivalent NaOCl mixture with deionized water. The EDTA-NaOCl solution did not dissolve more tissue than an equivalent pure EDTA solution at any time (anova, P > 0.05). CONCLUSIONS: Ethylenediamine tetraacetic acid retained its calcium-complexing ability when mixed with NaOCl, but EDTA caused NaOCl to lose its tissue-dissolving capacity and virtually no free chlorine was detected in the combinations. Clinically, this suggests that EDTA and NaOCl should be used separately. In an alternating irrigating regimen, copious amounts of NaOCl should be administered to wash out remnants of the EDTA.

Analysis of Variance↗
PubMed2003

Typing of Pseudomonas aeruginosa strains in Turkish cystic fibrosis patients.

The majority of cystic fibrosis (CF) patients suffer from chronic respiratory infection with the opportunistic bacterial pathogen Pseudomonas aeruginosa. The virulence of P. aeruginosa is associated with the presence of various extracellular factors, like alginate, elastase, alkaline protease which contribute tissue destruction and assist bacterial invasion. Virulence factor production of P. aeruginosa strains isolated from 46 CF patients followed in two cities in Turkey was detected. Strains were compared genotypically by arbitrarily primed PCR. Antimicrobial susceptibilities to 12 antibiotics were determined by broth microdilution method. Evaluation of virulence factor results revealed that 95.8% of the strains were alginate, 71.7% elastase and 52.1% alkaline protease producers. AP-PCR analysis revealed 35 genotypes indicated almost a complete discrepancy among the strains. The most effective drugs were penems and quinolones. Among aminoglycosides amikacin was the most effective one and a high level resistance to beta lactams was observed. Alginate is the most important virulence factor in the chronic colonisation of CF patients with P. aeruginosa. No evidence for cross infection between patients and for relationship between phenotypes and genotypes of the strains was found.

Alginates↗
PubMed2002

Resistance of an enamel-bonding agent to saliva and acid exposure in vitro assessed by liquid scintillation.

OBJECTIVES: To determine the leakage and resistance of a bonding agent and a light-curing fine hybrid composite when exposed to saliva or lactic acid (pH 4) in vitro. METHODS: Twenty discs in each of four groups of selected irradiated bovine lower central incisors were treated with one of three sealing options: an enamel bond (Heliobond, Vivadent, Schaan, Liechenstein) in a single-step application; Heliobond in a two-step application; and Tetric Flow (Vivadent) as the negative control. One group served as the positive control and remained unsealed. Loss of apatite was determined using the radiochemical method of liquid scintillation. The Cherenkov radiation was assessed in order to evaluate the acid resistance and leakage of smooth surface enamel bonding after exposure to saliva and lactic acid. In addition, replicas were made for SEM analysis of micromorphologic surface changes. RESULTS: A mean loss of 416.5 g (s.d. 57.0) apatite was observed over the unsealed sites following 14 days of exposure to lactic acid. The application of Heliobond in a one- and two-step application still revealed a remarkable degree of leakage, and substance losses of 196.5 g (s.d. 38.9) and 161.8 g (s.d. 39.7), but a protective potential was evident. In saliva, untreated, as well as sealed teeth, showed a modest leakage that was less than 20 g. When Tetric Flow was used (negative control) leakage was reduced to a minimum of 2.4 g (s.d. 1.0) in saliva and 12.8 g (s.d. 19.6) in lactic acid. These results were confirmed by SEM analysis. SIGNIFICANCE: The method of liquid scintillation was revealed to be of considerable value in evaluating leakage and acid resistance of potential smooth enamel sealing options. Sealing with an unfilled resin still demonstrated remarkable levels of acid dissolution, although a protection tendency could be observed. This leads to the conclusion that there is a need for further investigation to establish more acid-resistant enamel sealing agents.

Acrylates↗
PubMed2002

Detection of inflammatory lymph nodes in rabbits by 99mTc-HIG lymphoscintigraphy.

Tc-Human immunoglobulin G ( Tc-HIG) is a well-known radiopharmaceutical for the evaluation of inflammatory lesions. Recently, it has been demonstrated as a new agent for the visualization of the lymphatic system by our group. Our aim was to investigate the feasibility of detection of inflammatory lymph nodes by Tc-HIG lymphoscintigraphy. Ten adult New Zealand rabbits were used as group A. In a baseline study, 37 MBq Tc-HIG (0.1 ml) was injected into both hind legs of the rabbits, and sequential posterior gamma imaging with the rabbits lying prone was performed at 5, 15, 30, 60, 90 and 120 min using a single-headed gamma camera (Toshiba GCA G01 E). One week later, microorganisms ( ) were injected in a volume of 0.1 ml intradermally into the web space between the second and third toes in the bilateral hind legs of each rabbit in order to obtain inflammation in the popliteal lymph nodes. After 4 days, 37 MBq Tc-HIG (0.1 ml) was injected into the hind legs of the rabbits bilaterally, and sequential posterior gamma imaging was performed as described above (second study). Another group of 10 adult New Zealand rabbits (group B) was injected with the same microorganisms in the right hind legs only. After 4 days, scintigraphic imaging was carried out in the same way as described above (third study). Regions of interest were drawn over the injection sites and popliteal lymph nodes on each image for semiquantitative analysis. Count rates for each were calculated and a decay correction was applied. Time-activity curves were generated to show the percentage retention of radioactivity in each region. After the scintigraphic study, some of the group B rabbits were killed by intravenous injection of pentobarbitone (100-150 mg.kg, and both left and right lymph nodes were removed for microscopic examination. On the scintigrams, lymphatic channels and popliteal lymph nodes were visualized within 15 min. In the second study, bilateral popliteal lymph nodes were visualized more clearly than in the baseline study. The right popliteal lymph nodes of the rabbits were more clearly visualized in the third study. Semiquantitative analysis showed a higher percentage uptake of radioactivity in the right compared to the left popliteal lymph nodes in group B rabbits. Microscopic examination of the tissue sections demonstrated inflammation in the right lymph nodes of group B rabbits. In this preliminary study, it was found that Tc-HIG is a new promising agent for the demonstration and evaluation of inflammatory lymph nodes.

Animals↗
PubMed2001

Penetration of topical fluconazole into human aqueous humor.

The purpose of this study was to determine the aqueous levels and pharmacokinetics of topical fluconazole 0.2% upon single and multiple drop applications. Forty-nine patients undergoing cataract surgery were given topical fluconazole 0.2%. They either received single drop or a loading dose of 1 drop per 5 min for 20 min. Aqueous samples were obtained during surgery 5, 15, 30, 45 and 60 min after the last drop. The samples were analysed by high-pressure liquid chromatography to determine aqueous concentrations. After single and loading dose applications peak aqueous levels were achieved at 15 min (3.35 +/- 0.64 and 7.13 +/- 0.79 microg ml(-1), respectively). Both had a steady decrease in concentration at 30, 45 and 60 min down to 4.06 +/- 0.37 microg ml(-1)with loading dose and undetectable levels with single dose application. Comparing the concentrations with the minimum inhibitory concentrations (MIC) of yeasts determined by the National Committee for Clinical Laboratory Standards showed that concentrations achieved with single dose applications were higher than MICs of Candida albicans and Candida parapsilosis and concentrations achieved after loading dose applications were higher than MICs of C. parapsilosis, C. albicans and Candida tropicalis. We concluded that topical fluconazole 0.2% penetrates into the aqueous humor in concentrations that satisfy MICs of most of the Candida strains. It can be a good alternative to Amphotericin B for treatment of Candida keratitis.

Administration, Topical↗
PubMed2001

Epidemiology of chronic Pseudomonas aeruginosa infections in cystic fibrosis.

Chronic lung infection with Pseudomonas aeruginosa is primarily responsible for pulmonary deterioration of cystic fibrosis patients. The purpose of this study was to type the P. aeruginosa isolates collected sequentially from cystic fibrosis patients, chronically colonized with P. aeruginosa, by random amplified polymorphic DNA fingerprinting-PCR (RAPD-PCR). Sequential P. aeruginosa isolates (n: 130) that had been collected from 20 CF patients over at least 9 years were investigated. The isolates were analyzed by RAPD-PCR using two arbitrary primers. Antimicrobial susceptibility testing of all isolates was performed by the disc diffusion method. RAPD-PCR typing demonstrated that strains dissimilar in colony morphotype and of different antibiotic susceptibility patterns could be of the same genotype. Some CF patients were colonized with a rather constant P. aeruginosa flora, with strains of different phenotypes but of one genotype. However, some patients may be colonized with more than one genotype. The results also demonstrated that there might be a risk of cross-colonization between CF patients followed-up at the same center.

Adolescent↗
PubMed2001

Antibacterial activity of fifth-generation dentin bonding systems.

Past concepts that the pulp does not become infected until an actual carious exposure takes place have been challenged. The antibacterial effects of the dentin bonding systems Single Bond, Prime&Bond NT, and Excite were evaluated using the bacteria Streptococcus mutans ATCC 25175, Streptococcus intermedius, Lactobacillus acidophilus, Prevotella oris, Prevotella bivia, Prevotella denticola, Porphyromonas gingivalis, Porphyromonas endodontalis, and Clostridium ramosum with a disk diffusion method. Chlorhexidine (0.2%) was used as a positive control. After incubation zones of inhibited bacterial growth were measured. Prime&Bond NT showed growth inhibition for all bacterial strains. Lactobacillus acidophilus and Streptococcus mutans were remarkably resistant to Single Bond, whereas EX produced no inhibitory effect on Porphyromonas endodontalis, although the adhesive produced the maximum halo inhibition to Streptococcus mutans (15+/-1 mm), showing an antibacterial effect closest to chlorhexidine. The variety of results obtained in this study suggest that antibacterial properties of current dentin adhesives may depend on components that are originally incorporated to promote adhesion.

Anti-Infective Agents, Local↗
PubMed2001

Toxicity of dietary Heliotropium dolosum seed to mice.

Experimental pyrrolizidine alkaloid intoxication was produced in inbred Swiss mice. Animals were fed diets containing 0, 1, 3, 5, or 10% Heliotropium dolosum seed for 24 w. The seeds contained 0.13% total alkaloid concentration composed of 4 specific components: lasiocarpine (78.79%), heliosupine (11.96%), echimidine (5.43%), and heliotrine (3.82%). Deaths occurred in all dosed groups and increased with dietary seed concentration. Massive to submassive liver necrosis together with sinusoidal congestion, and hemorrhage or multifocal hepatocytic necrosis was limited to animals which survived < 5 w and were fed on 10% seed. Moderate to severe hepatomegalocytosis, scattered single cell necrosis, and mild subcapsuler fibrosis were seen in all test group animals that survived > 5 w. Intranuclear eosinophilic inclusions in hepatocytes and bile duct and ductular cell hyperplasia were the most noticeable lesions in the 1, 3, and 5% groups. There was mild to moderate renal tubular megalocytosis in the 3, 5, and 10% groups. It seems likely that H dolosum seed, at least to a limited extent, constitutes a health hazard for certain animal species.

Animals↗
PubMed2000

Anti-ulcerogenic effect of Momordica charantia L. fruits on various ulcer models in rats.

The mature fruits of Momordica charantia L. (Cucurbitaceae) are used externally for the rapid healing of wounds and internally for the treatment of peptic ulcers in Turkish folk medicine. For the evaluation of the latter activity, ethanol-induced ulcerogenesis model in rats was employed. The olive oil extract of the material as well as dried-powdered fruits in filtered honey showed significant and dose-dependent anti-ulcerogenic activity against this model. A potent and dose-dependent inhibitory activity was also observed by the administration of ethanol extract of the fruits. For the bioassay-guided fractionation, the material was first extracted with hexane and then by ethanol and both extracts were found active against the same ulcer model. Furthermore, ethanol extract of the fruits showed significant activity against HCl-EtOH induced ulcerogenesis in indomethacin-pretreated rats and diethyldithiocarbamate-induced ulcer models.

Animals↗
PubMed2000

Apical nodular subepithelial corneal scar after retreatment in hyperopic photorefractive keratectomy.

PURPOSE: To report a complication, apical nodular subepithelial corneal scar, that can occur after hyperopic photorefractive keratectomy (PRK) retreatment. SETTING: Istanbul University Eye Research Center, Istanbul, Turkey. METHODS: Twelve eyes of 6 patients with apical nodular subepithelial corneal scar were retrospectively studied. Mean age of the 5 men and 1 woman was 30.2 years +/- 5.4 (SD). All eyes had hyperopic PRK retreatment for regression 9.5 +/- 1.44 months after primary hyperopic PRK. Mean spherical equivalent refraction of the residual hyperopia before retreatment was +4.67 +/- 0.81 diopters (D). All patients had a corneal haze grade of less than 1+. Hyperopic PRK retreatment was performed with a 193 nm excimer laser (Chiron Technolas Keracor 116). RESULTS: Apical nodular subepithelial corneal scars developed within the first month of hyperopic PRK retreatment and progressed until the third month in 12 eyes of 6 patients. The lesion was round and symmetrical in both eyes, smaller than 2.0 mm, and centrally located. During the mean 40.66 +/- 2.46 month follow-up, the lesion did not change in size or density. Mean spherical equivalent refraction after retreatment was 2.88 +/- 0.88 D (range +1.50 to +4.00 D) at 1 month and +4.36 +/- 1.83 D at last follow-up. Refraction was unmeasurable in 3 eyes. Five eyes lost 1 line of best spectacle-corrected visual acuity and 7 eyes, 2 or more lines. The surface regularity indexes were higher than 2.00 in all the eyes. CONCLUSION: Hyperopic PRK retreatment may cause the sight-threatening complication of apical nodular subepithelial corneal scar. This complication behaves unlike corneal haze and does not resolve spontaneously over time.

Adult↗
PubMed2000

Triterpenoid saponins from Bongardia chrysogonum.

Two new triterpenoid saponins, 3-O-[beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-alph a-L-arabinopyranosyl]-hederagenin (1) and 3-O-[beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-alph a-L-arabinopyranosyl]-hederagenin 28-O-[beta-L-glucopyranosyl-(1-->6)-beta-L-glucopyranosyl] ester (2), together with five known saponins, were isolated from an ethanolic extract of the tubers of Bongardia chrysogonum. The structures of 1 and 2 were determined on the basis of spectroscopic studies.

Chromatography, High Pressure Liquid↗
PubMed1999

Secondary laser in situ keratomileusis 1 year after primary LASIK for high myopia.

PURPOSE: To report the results of the laser in situ keratomileusis (LASIK) using a second-cut hinged corneal flap to treat regression 1 year after primary LASIK for high myopia. SETTING: Istanbul University, Eye Research Center, Istanbul, Turkey. METHODS: Six eyes of 4 patients who had a mean myopic regression of -6.20 diopters (D) +/- 1.10 (SD) 1 year after primary LASIK were retreated with secondary LASIK performed using the Automated Corneal Shaper (Chiron Vision) and a 193 nm excimer laser (Chiron Technolas, Keracor 116). Fluence was 130 mJ/cm2 and the repetition rate, 10 Hz. RESULTS: Mean follow-up was 12.16 +/- 0.75 months. At the last follow-up, the mean spherical equivalent was -0.18 +/- 0.77 D (range +0.12 to -1.25 D). Two eyes (33.3%) remained within +/- 0.50 D of emmetropia; 5 eyes (83.3%) were within +/- 1.00 D of emmetropia. No patient lost best spectacle-corrected visual acuity. No complications occurred such as detachment of the former corneal flap and rolling, irregularity, or tearing of the new corneal flap. CONCLUSION: Secondary LASIK was an effective, safe method to treat regression after primary LASIK for high myopia.

Adult↗
PubMed1999

New steroidal alkaloids from the roots of buxus sempervirens

Phytochemical studies on an EtOH-soluble extract of the roots of Buxus sempervirens of Turkish origin have resulted in the isolation of three new steroidal alkaloids, (+)-semperviraminol (1), (+)-buxamine F (2), and (+)-17-oxocycloprotobuxine (3), along with two known steroidal alkaloids, (+)-buxoxybenzamine (4) and (+)-buxapapillinine (5). The structures of 1-3 were elucidated with the aid of spectroscopic studies. Compounds 4 and 5 exhibited phytotoxic activity against Lemna minor.

Journal Article↗