Biomedical subjects

M Mutlu

Publications and source records attributed to M Mutlu.

13 recordsLinked to original sources

PubMed2003

The effects of HEMA-monomer and air atmosphere treatment of glass fibre on the transverse strength of a provisional fixed partial denture resin.

This study focused on some mechanical properties such as the transverse strength, the maximal deflection, and the modulus of elasticity of resin reinforced with two different types of agents-treated and with untreated glass fibre, and without fibre. A Teflon mould was used to prepare six groups of specimens. Two different types of chemical modification agents, hydroxyethyl-methacrylate (HEMA)-monomer and air atmosphere were applied to create hydrophilic surfaces on the glass fibres. The flow rate was kept at two different levels, 25 and 60 mL min-1. The discharge powers of the surface treatment process were 15 or 20 W. The fibres were exposed to glow discharge conditions for the periods of 10 or 15 min. Without fibre specimens were the control group. The provisional resin was same in all groups. All the specimens were subjected to transverse testing with a cross-head speed of 5 mm min-1. The three-point load test was used to record the load of the fracture for each specimens. The Kruskal-Wallis analysis of variance was used to compare the transverse strength, the maximal deflection and the modulus of elasticity. The differences in the transverse strength and the maximal deflection between the six groups were found statistically significant but the modulus of elasticity was not statistically significant. The transverse strength of HEMA-monomer (group A) was shown the highest value (66.3 MPa). For without-fibre group, the value was 52.9 MPa. This difference was statistically significant when the Mann-Whitney U-test was used for comparing. Repairing or remaking provisional restorations can be a time-consuming endeavour. The added strength of the polymethyl methacrylate with the fibre can reduce clinical failures of provisional fixed partial dentures. The surface treatment process was increased the transverse strength and the maximal deflection. The clinical implication of chemical modification agents-coated fibres is reduced incidence of fixed provisional restoration failure.

Acrylic Resins↗

PubMed2000

The pelvic external fixation: the mid-term results of 41 patients treated with a newly designed fixator.

The purpose of this study was to evaluate the clinical and radiological results of unstable pelvic fractures treated with a new external fixation device. Between May 1992 and May 1998, 43 patients with unstable pelvic fractures were treated with a new anterior pelvic external fixator. Two died, and therefore 41 patients' results were evaluated. There were 29 men and 12 women, and their average age was 34 years (range 12-70 years). Traffic accidents accounted for 34 injuries. Three patients fell from a height, 3 were injured in industrial accidents, and 1 was hit by a train. According to the Tile classification, there were 24 type B pelvic injuries and 17 type C. Associated injuries were observed in 21 patients. A considerable reduction of the pelvic pain was noted after application of the fixator in all patients. Excessive blood transfusion was not required in any patient. The average follow-up was 24 months (range 12-50 months). Clinical results at final evaluation were good according to the criteria of Matta and Saucedo in 34 patients and poor in 7. In conclusion, the new pelvic external fixator is effective, safe, and easy to apply in the treatment of unstable pelvic fractures. The fixator can be used alone in patients with type B pelvic injuries such as open book and lateral compression. However, it does not provide sufficient stability for severely displaced type C injuries when applied alone. Nevertheless, it may be helpful for fixing type C injuries like a posterior iliac fracture without dislocation of the sacroiliac joint.

Adolescent↗

PubMed1998

Hemodynamic monitoring of the contralateral testis during unilateral testicular torsion describes the mechanism of damage.

Contralateral testicular perfusion during unilateral testicular torsion was evaluated using simultaneous blood flow and O2 content determinations. Two groups, each consisting of 7 rats, were studied. Sham operation or 720 degrees clockwise twisting was performed on the left testes, and blood flow, O2 content and temperatures were monitored in the right testes for 180 min. An ultrasonic perivascular Doppler flowmeter system, an electronic thermometer and an O2 electrode were used for the monitoring. The contralateral testicular blood flow and relative O2 contents were stable in the control group. However, the initial and 180 min blood flow values decreased from 0.21 +/- 0.04 to 0.11 +/- 0.02 ml/min (p < 0.001), and the O2 contents from 0.857 +/- 0.123 to 0.319 +/- 0.037 (1.0 corresponds to 19.6 mm Hg pO2, p < 0.05) in the experimental group. Unilateral testicular torsion decreases the blood flow and O2 content of the contralateral testis. The contralateral testicular injury encountered following unilateral testicular torsion might result from hypoxia following the decrease in blood flow.

Animals↗

PubMed1998

Estrogen and progesterone receptors in the peripheral giant cell granulomas of the oral cavity.

Peripheral giant cell granulomas are common proliferative lesions of the oral cavity with a predilection for females. In this study, the presence of estrogen and progesterone receptors in 26 peripheral giant cell granuloma cases were studied utilizing the immunoperoxidase technique. In fourteen cases, estrogen receptor positivity was found in stromal cells. In ten of these, osteoclast-type giant cells also exhibited estrogen receptor immunostaining. Progesterone receptor expression was not detected. It was concluded that the cells forming peripheral giant cell granuloma are potential targets for estrogens and that these lesions might be conditioned by sex hormones.

Adolescent↗

PubMed1992

A study of macromolecular diffusion through native porcine mucus.

A diffusion chamber technique based on time-lag analysis for the estimation of effective diffusion coefficients of radiolabelled macromolecules of varying molecular weights through native mucus gel is reported. For all solutes studied, a reduction in effective diffusion coefficients was observed with a retardation of solute flux in both aqueous and mucus layers. Over the molecular weight range of solutes investigated (126-186,000 Daltons), a consistent effect of molecular weight was evident with regard to the retarding effect of mucus. No apparent or absolute molecular weight cut-off for macromolecular transfer was exhibited. However, at high molecular weights (greater than 30,000 Daltons) the retardation was greatly enhanced. The results confirm that mucus can be regarded as a gel with finite pores, but that it does not constitute an absolute barrier to even high molecular weight solutes.

Animals↗

PubMed1991

Evaluation of 99mTc labelled monodisperse polystyrene/polyacrylate latex particles for the study of colon transit and morphology.

A new radiopharmaceutical for the study of colon transit time and morphology is proposed. Polymeric latexes, as monodisperse polymeric spheres (1-10 microns in diameter), were prepared by a coaxial dispersion polymerization of styrene and dimethylaminoethyl-methacrylate (DMAEA). They were labelled with 99mTc by the tin reduction method with high efficiency (greater than 99%). The label was stable up to 48 h at pH values of 1-8 at room temperature. Scintigrams obtained in rabbits after oral administration of 37 MBq of 99mTc-latex particles showed that greater than 90% of the dose remained in the gastrointestinal tract. The cumulative faecal excretion was 8.6 +/- 6.7 in 24 h and 21.3 +/- 13.8% in 48 h. In human studies the colon was well visualized at 4 h. The thyroid and the urinary bladder were not detected on scintigrams, indicating the stability of the label in vivo. Our results demonstrated that the radiopharmaceutical developed in the present study was ideal for the intended purpose.

Adult↗

PubMed1990

Blood plasma proteins on polyurethane and alkylsiloxane plasma-treated polyurethane surfaces. Dynamic approach by stimulus-response technique. Part 2. Evaluation of adsorption data by moment technique.

In this study, interactions of blood proteins (i.e. albumin and fibrinogen) with polyurethane biomaterial surfaces were investigated in an in vitro bead column test circuit using a stimulus-response technique. The dynamic sorption process of radiolabelled proteins on the surfaces was followed by detecting the radioactivity at the exit stream of the column, which was the response of a pulse stimulus at the inlet. The mathematical model was described and solved using 'parameter estimation by cybernetic moment technique', and the adsorption rate constants of plasma proteins on different biomaterial surfaces were calculated. By evaluation of the response curves with standard and cybernetic moment techniques, the following results were obtained. Albumin and fibrinogen adsorption is competitive, and the competition is strongly dependent upon the surface characteristics of the biomaterial. Preadsorption or preferential adsorption of albumin decreases the fibrinogen adsorption, and therefore increases the biocompatibility of material surface. Adsorption of blood plasma proteins are irreversible. The moment technique can also be used for the evaluation of stimulus-response data of biological systems, to determine the process parameters.

Adsorption↗

PubMed1989

99mTc-MDP adsorption of some dental alloys with varying surface roughness: effect of oral environment.

The purpose of this study was to measure the surface characteristics of some dental alloys by 99mTc-MDP adsorption and to investigate the effect of oral environment on 99mTc-MDP adsorption. Sample discs of five different dental alloys were prepared. The surfaces were sandblasted, ground with sandpaper, polished and electrolysed in succession. The surface roughness of each disc was measured by the use of a profilometre. Contact angles (theta) of the surfaces were also measured. 99mTc-MDP adsorption of the discs was determined both prior to and after 2 h of exposure to the oral environment. Our results indicated that the discs sandblasted and electrolysed had the maximum surface roughness and those polished the minimum surface roughness. The 99mTc-MDP adsorption showed variation according to the type of alloy used and its surface roughness prior to exposure to the oral environment. After exposure 99mTc-MDP adsorption was essentially the same for all the alloys.

Adsorption↗

PubMed1984

Preparation of polyethyleneglycol (PEG) coatings for microencapsulation of charcoal.

Polyethyleneglycols (PEGs) with their high solubility in water cannot normally be used as a coating material in aqueous solutions such as blood. A gamma-radiation procedure was therefore applied after coating charcoal granules with PEG in a non-aqueous phase, and an 80-90% insoluble polymer matrix on charcoal was obtained. PEGs with different molecular weights from 4000 to 300,000 were used for coating. The performance of this system was determined by using several test solutes, namely creatinine, uric acid, and vitamin B-12. It was observed that the pore size and structure of these membranes can be adjusted by changing the irradiation time and by using PEGs with different molecular weights. Thus, very high mass transfer rates can be achieved.

Adsorption↗

PubMedDate not supplied

Evaluation of 99mTc labelled poly lactic acid microspheres for diagnostic radioembolization.

Radioembolization is used in diagnostic imaging of the lungs and for radioembolization therapy of hepatic tumours. Presently, 99mTc labelled macroaggregates or microspheres of human serum albumin (HAM) are used for this purpose. Poly lactic acid (PLA) is biodegradable, like HAM, and, unlike HAM, is not a blood product. The aim of the present study was to evaluate the uptake and biodegradation of PLA microspheres in lungs. PLA (MW = 48720 Da) microspheres of 1.0-100 microm (mean = 39.5 microm) in diameter were prepared by solvent evaporation from methylene chloride. They were labelled with 99mTc by stannous chloride reduction at pH 3, with an efficiency of 98% and a stability of 96% at 24 h. For biodistribution studies, 15 mice were i.v. injected with 20 microCi 99mTc-PLA microspheres in 0.1 ml and sacrificed at 15 min, 1, 3, 6 and 24 h (three at each time point). All the organs were removed, weighed and counted against a standard prepared from 1/100 dilution of the injected radioactivity. Some mice were similarly injected and sacrificed at 30 min, 15 and 30 days. The lungs were removed and frozen, and 10 microm sections were obtained, stained with haemotoxylin and eosin and examined under a light microscope. Five rabbits were i.v. injected with 1 mCi of 99mTc-PLA microspheres. Scintigrams were obtained at various intervals up to 24 h. In mice, the lung uptake was significant at 30 min-1h post-injection. In rabbits, the lungs were the only organs visualized up to 24 h. Microscopic examination of tissue sections demonstrated slow biodegradation of PLA particles. In conclusion; (1) The high lung uptake obtained in mice and rabbits indicates the suitability of PLA microspheres for lung imaging, and (2) although the slow biodegradation rate might be a disadvantage in patients with lung disorders in diagnostic studies, it may be an advantage in therapeutic applications with radionuclides which have long physical half lives.

Animals↗

PubMedDate not supplied

Preliminary traction as a single determinant of avascular necrosis in developmental dislocation of the hip.

The role of preliminary traction before closed reduction in the treatment of developmental dysplasia of the hip has been questioned by many authors lately. However, the studies advocating or opposing the use of this treatment modality include several other parameters besides traction. Thus, it is unclear whether the affection is the result of preliminary traction or concurrent variables such as the "human position." This study aimed to put forward the effect of preliminary traction as a single determinant of avascular necrosis. We had two groups of patients who had developmental dislocation of the hip. The first group consisted of 52 patients treated with preliminary traction before closed reduction and the other group comprised 40 patients treated with closed reduction without preliminary traction. Both groups were similar in age, gender, side, level of dislocation, and method and duration of immobilization. Three patients from the first group developed avascular necrosis, which was not statistically significant. Preliminary traction did not affect the rate of avascular necrosis.

Age Factors↗

PubMedDate not supplied

The de Barsy syndrome.

We report a child with de Barsy syndrome, which is a very rare, genetically transmitted clinical entity associated with mental and growth retardation, severe cutis laxa, joint laxity and various ocular and skeletal system findings. The patient was operated to treat her orthopedic disabilities. Typical findings of this case with eight-year follow-up beginning from birth are described and compared with previously reported cases. The main aim of this paper was to describe the diagnostic and therapeutic difficulties of this rarely encountered syndrome.

Abnormalities, Multiple↗

PubMedDate not supplied

Congenital dislocation of the hip and its relation to swaddling used in Turkey.

A screening program was initiated and performed at five hospitals in Konya, Turkey from 1988 to 1990. Four thousand one hundred seventy-three infants aged 3-24 months were examined. With this study, we hoped to determine the incidence of and contributing factors to the etiology of congenital dislocation of the hip (CDH) in the central region of Turkey. The overall CDH incidence was 1.34%. CDH occurred about three times more often among girls than boys (40 girls vs. 16 boys). No infant with CDH had been delivered by Cesarean section or breech presentation. No teratologic CDH was detected. The relationship between CDH and swaddling (bundled in extension and adduction) was statistically significant.

Culture↗