Biomedical subjects

Mehmet Erdem

Publications and source records attributed to Mehmet Erdem.

At least 19 recordsLinked to original sources

PubMed2007

Effects of diclofenac and tenoxicam on distraction osteogenesis.

INTRODUCTION: In the management of bone defects, pseudoarthrosis, deformities, chronic osteomyelitis and in extremity lengthening procedures, the technique of distraction osteogenesis (DO) has been frequently used. In this experimental animal study, the effects of two non-steroidal anti-inflammatory drugs, i.e., diclofenac and tenoxicam, on the outcomes of distraction osteogenesis are investigated. MATERIALS AND METHODS: In this study, 30 mature New Zealand-type male rabbits (2.5-4.5 kg) were used. The rabbits were randomized into three groups, each consisting of ten animals. Under optimal operating conditions, a pre-reconstructed circular external fixator was applied on the right tibias of rabbits, and osteotomy was performed with a Gigli saw just below the tibial tuberosity. After seven postoperative days, distraction was initiated at a rhythm of 2 x 0.5 mm/day. During the 10 days of distraction, adjunctive therapy was not instituted for group I (control group). For 10 days, group II received i.m. diclofenac sodium (0.5 mg/kg per day) and group III was treated with tenoxicam (8 mg/kg per day i.m.). At the end of 3 weeks postoperatively, five rabbits from each group were killed for histologic examinations. The remaining rabbits were killed at the end of eight postoperative weeks for biomechanical and histological analysis. Besides, radiological examinations were performed at the end of 3, 6 and 8 weeks postoperatively for the radiologic evaluation of calluses. For statistical evaluations between groups, Kruskal-Wallis variance analysis, and for intergroup assessments, Mann-Whitney test were performed. RESULTS: For radiological evaluations, the scoring system developed by Lane and Sandhu, and for histopathological assessments, the grading system of Huddlestone et al. were used. Biomechanical tests were realized using torsional loading. During the first 3 weeks, the groups did not differ much in the radiological parameters. However, in the diclofenac group and in especially the tenoxicam group, the histological scores were lower than in the control group. Radiological images obtained at the end of 6 weeks demonstrated inadequate consolidation in the diclofenac and tenoxicam groups when compared with the control group. At the end of 8 weeks postoperatively, in consideration of biomechanical, radiological and histological tests, significantly worse regenerates were obtained in the diclofenac and tenoxicam groups. CONCLUSIONS: During the distraction osteogenesis period, diclofenac and tenoxicam affected the quality of regenerate unfavorably. This effect is sustained during all periods of bone healing. However, this finding should be supported by experimental and human studies.

Animals↗

PubMed2006

Polygonal triple (Kotz) osteotomy (over 10 years experience).

We evaluated the results of polygonal triple (Kotz) osteotomy for the treatment of acetabular dysplasia over 10 years. This study included 31 hips of 27 patients who had the Kotz osteotomy for acetabular dysplasia. The mean age was 21.5 years. We performed the original Kotz osteotomy for the first 22 hips (group I), while the modified Kotz osteotomy through an intra-pelvic approach without damage to the abductor muscle was applied for the last 9 hips (group II). Patients were evaluated by clinically and radiologically. The average follow-up was 106 months in group I, and 18 months in group II. The Trendelenburg gait was unchanged for four patients in group I and for one patient in group II. The Harris Hip Score improved in all patients postoperatively. Radiographic assesment showed improvement in both groups in terms of the angle of CE, VCE, and Sharp postoperatively(P<0.05). The complication rate per hip was 0.29. The original Kotz osteotomy achieves adequate coverage for the treatment of acetabular dysplasia, and patients are generally satisfied by this procedure. Nonetheless, the modified Kotz osteotomy provides recovery of the abductor muscle strength in the early postoperative period and subsequently decreases the rate of the Trendelenburg gait compared to the original Kotz osteotomy.

Adolescent↗

PubMed2006

Tibial slope and high tibial osteotomy using the circular external fixator.

Alteration of tibial slope is one of the important anatomical changes of the proximal tibia after high tibial osteotomy. Increased or decreased tibial slope can effect further total knee prosthesis procedure. In this retrospective study, 18 knees of 17 patients (17 female, mean age 51 range 43-61, mean BMI is 33.6 +/- 4.6 kg/m2) who were applied high tibial osteotomy using circular external fixator due to medial compartment arthrosis of the knee were evaluated in terms of tibial slope changes. While mean correction about 12.3 degrees in mechanical femoro-tibial angle was obtained in frontal plan (P = 0.0001), significant change in tibial slope was not determined in sagittal plan (P = 0.127). The mean posterior proximal femoral angle values were measured as 79.5 +/- 2.1 degrees preoperatively and as 80.3 +/- 2.7 degrees postoperatively and found to fall into the normal range (80.4 +/- 1.6 degrees). As there is no significant alteration in tibial slope after high tibial osteotomy performed with the Ilizarov system, complications due to alteration in tibial slope will not be experienced in follow-up or in further total knee prosthesis procedure.

Adult↗

PubMed2006

CD105 expression is an independent predictor of survival in patients with endometrial cancer.

OBJECTIVE: The purpose of this study was to detect the prognostic value of CD105 (endoglin) and also to compare with CD34 and vascular endothelial growth factor (VEGF) in patients with endometrial adenocancer. METHODS: Ninety patients with endometrial carcinoma, who were treated at Gazi University Hospital, were included. Staging was performed according to the FIGO recommendations. Angiogenesis was estimated by using CD105 and CD34 and tested for possible significant relation with age, stage, histologic type, grade, depth of myometrial invasion, lymphovascular space invasion, lymph node metastasis, and overall survival (OS). In addition, VEGF staining intensity and distribution were analyzed with respect to all these variables. RESULTS: The mean age at the time of diagnosis was 57.7 years (range, 28-81 years). The mean microvessel density (MVD) for CD105 was 32.87+/-19.99, and it was 55.46+/-31.25 for CD34 (P<0.001). A significant correlation was noted between these two markers (r=0.257, P=0.02). The mean VEGF score was 4.13+/-1.73, and it was significantly correlated with MV counts determined by CD105 (r=0.291, P=0.006). It was not significantly related with CD34 (r=0.031, P=0.78). With respect to clinicopathological variables, none of the comparisons was found to be significant. The mean follow-up period was 60.5 months. To analyze the prognostic value of MVD, the patients were divided into three groups with respect to quartiles ( or=75%). With CD105 staining, the 5-year OS rates for patients with the highest MVD count (>or=75%) were significantly poorer than the remaining two groups (P=0.01 for both). None of the comparisons for CD34 was significant. Survival analysis for VEGF was performed by grouping patients using staining characteristics. No significant difference was noted for OS. Multivariate analysis showed that MVD determined by CD105 correlated significantly and independently with OS (P=0.02). None of the remaining variables was significant in multivariate analysis. CONCLUSION: The current study showed that CD105 is an independent predictor of survival in patients with endometrial cancer. We recommend the use of this highly specific and prognosis-related antigen in further investigations.

Adenocarcinoma↗

PubMed2006

Cu2+, Cd2+ and Pb2+ adsorption from aqueous solutions by pyrite and synthetic iron sulphide.

In this study, removal of Cu(2+), Cd(2+) and Pb(2+) from aqueous solutions by adsorption onto pyrite and synthetic iron sulphide (SIS) was investigated as a function of pH, contact time, adsorbent dosage, initial metal concentration and temperature. It has been determined that the adsorption of metal ions onto both adsorbents is pH dependent and the adsorption capacities increase with the increasing temperature. The mechanisms governing the metal removal processes were determined as chemical precipitation at low pH (<3) due to H(2)S generation and adsorption at high pH (in the range of 3-6). The metal adsorption yields also increased with the increasing adsorbent dosage and contact time and reached to equilibrium for both adsorbents. The Cu(2+), Cd(2+) and Pb(2+) adsorption capacities of both adsorbents decrease in the order of Pb(2+)>Cu(2+)>Cd(2+). Except for cadmium, little fraction of copper and lead in the solid adsorption residues was desorbed in acidic media.

Adsorption↗

PubMed2006

Effects of calcitonin and alendronate on distraction osteogenesis.

In this experimental animal study the effects of calcitonin and alendronate on distraction osteogenesis are investigated. Forty-five mature female New Zealand type rabbits were used. Rabbits were randomized into three groups, each consisting of 15 animals. Under optimal operating conditions a pre-reconstructed circular external fixator was applied to the right tibia of rabbits, and osteotomy was performed with a Gigli saw just below the tibial tuberosity. During the ten days of distraction, a placebo was administered for group I (control group), group II received 10 U of calcitonin, and group III was treated with alendronate (0.5 mg/kg/day) gavages. Rabbits were examined histologically (at the third and eighth weeks, according to Huddlestone et al.), radiologically (at the third, sixth, and eighth weeks, according to Lane and Sandhu), and mechanically (at the eighth week, as torsional loading). During the first three weeks, the groups did not differ much with regard to radiological parameters. However, in the calcitonin and alendronate groups improved histological scores were detected compared with the control group. Radiological images obtained at the end of six weeks demonstrated improved consolidation in the calcitonin and alendronate groups compared with the control group. At the end of eight weeks postoperatively, radiological and histological parameters did not differ among the groups, while torsional failure load was found to be much improved in the calcitonin group (p=0.006). During the distraction osteogenesis period, calcitonin and alendronate affected the quality of regenerate favourably. This effect is sustained until the end of the consolidation period. However, this finding needs to be supported by experimental and human studies.

Alendronate↗

PubMed2006

[Combination of microfracture and periosteal transplantation techniques for the treatment of full-thickness cartilage defects].

OBJECTIVES: Microfracture and periosteal transplantation techniques were combined in order to enhance the quality of repair for the treatment of full-thickness cartilage defects. METHODS: In 40 mature New Zealand white rabbits, a full-thickness cartilage defect of 4 mm was induced on the weight-bearing surfaces of the medial condyles of the right femur. The rabbits were randomly divided into four groups equal in size. Control animals remained untreated following defect induction. Two groups were either treated with periosteal transplantation or the microfracture technique, while the fourth group underwent combination of the two techniques. All the animals were immobilized for two weeks postoperatively. At the end of 12 weeks, the animals were sacrificed and the specimens were removed for evaluation according to the criteria of the ICRS scale (International Cartilage Repair Society), and with respect to newly regenerated cartilage areas and the number of viable chondrocytes. RESULTS: Specimens treated with the combination of the two techniques exhibited significant differences from the other groups in all criteria of the ICRS scale (surface, matrix, cellular distribution, cell viability, and cartilage mineralization) except for subchondral bone criteria. In addition, the mean number of viable chondrocytes and newly regenerated cartilage areas were the highest in this group (p=0.0001). CONCLUSION: Due to markedly improved quality of repair, the combination of the microfracture and periosteal flap techniques seems to be more effective than either of the techniques used alone in the treatment of cartilage defects.

Animals↗

PubMed2006

[Atraumatic bilateral patellar tendon rupture in a patient receiving steroid therapy].

Atraumatic bilateral patellar tendon rupture is a rare entity. It is usually due to systemic or local disorders causing tendon degeneration. Early diagnosis and surgical treatment are crucial for recovery of knee functions. Atraumatic bilateral patellar tendon rupture was diagnosed in a 31-year-old female patient who had been receiving steroid therapy for seven years due to systemic lupus erythematosus. She underwent patellar tendon reconstruction with the use of semitendinosus and gracilis tendons. After a follow-up of six months, she could walk without crutches and had a full range of motion.

Adult↗

PubMed2005

Chromium recovery from chrome shaving generated in tanning process.

In this study, the chromium recovery conditions in the form of soluble chromate from chrome shaving (chromium-containing solid waste) by oxidation with air, oxygen and Na2O2 were investigated and basic Cr(III) sulphate solution using in the tanning was prepared from the chromate obtained. It has been determined that the oxidation agent is the most effective parameter affecting the chromate formation. While maximum oxidation yields in air and oxygen atmosphere at 850 degrees C were found to be 23.02 and 30.41%, respectively, the highest chromium recovery efficiency in the form of chromate (99.45%) occurred in the presence of eight times Na2O2 with respect to stoichiometric amount of chromium. The chromate generated in Na2O2 oxidation process where 99.45% of chromium in the chrome shaving can be recovered was leached with distilled water and pregnant chromate solution was prepared. The chromate ions in this solution were reduced by using Na2SO3 and Cr(III) sulphate solution was obtained.

Chromium↗

PubMed2005

Hexavalent chromium removal by ferrochromium slag.

The aim of this study is to demonstrate the potential of Cr(VI) generation during jigging operation applied for ferrochrome recovery from slag. The Cr(VI) concentrations of water contacted with ferrochromium slag (W/FS=10) in a closed cycle after 50 batches were found as 0.61 mg/l. Also, reduction of Cr(VI) to Cr(III) and a subsequent precipitation of Cr(III) by using ferrochrome slag (FS) in a model solution has been aimed. The effects of amount of acid, contact time, FS dosage, initial Cr(VI) concentration and temperature on the Cr(VI) reduction have been studied through the batch runs. The amount of acid has been found to be the most effective parameter affecting the Cr(VI) reduction. A 10 g/l FS dosage and 3.5 ml/l H2SO4 (5M) are sufficient to reduce all Cr(VI) in the model solution containing 10mg/l Cr(VI) and for contact time of 60 min at 25 degrees C. In reduced solutions, precipitation of metal ions has been studied by using extra FS. A 60 g/l dosage of fresh FS can precipitate all Cr(III) and Fe ions in the reduced solution. Thus, it has been demonstrated that the treatment of jigging water stream to be generated in a ferrochrome plant containing Cr(VI) can be accomplished by using ferrochromium slag and sulphuric acid. Also, it has been determined that solid residues of the process are environmentally stable by applying TCLP test.

Calcium Carbonate↗

PubMed2005

Prediction of spontaneous onset of labor at term: the role of cervical length measurement and funneling of internal cervical os detected by transvaginal ultrasonography.

The objective of this study was to examine the values of the cervical length measurement and detection of internal cervical os funneling by transvaginal ultrasonography in the prediction of spontaneous labor within a 7-day period at term. Ninety-three pregnant women were enrolled into this study. All patients were evaluated by transvaginal ultrasonography first at the 37th completed week of gestation and weekly thereafter. Endocervical canal length was measured and the presence of funneling was recorded. The end points were the percentage of patients with a spontaneous onset of labor in the week after these data were recorded. The optimal cutoff values for predicting the onset of spontaneous labor within 7 days were 29.5 mm for cervical length at 37 weeks, 27.5 mm at 38 weeks, 25.5 mm at 39 weeks, and 24.5 mm at 40 weeks of gestation. There was also statistically significant agreement between the presence of the funneling and spontaneous labor within 7 days. Measurement of cervical length and detection of funneling at the internal cervical os by transvaginal ultrasonography might help us to predict the spontaneous onset of labor in a 7-day period, and help clinicians to decide about the time of labor induction in certain complicated pregnancies.

Adult↗

PubMed2005

[A case of congenital pseudarthrosis of the clavicle].

Congenital pseudarthrosis of the clavicle is a rare condition of unknown etiology. It usually presents as a painless mass in the clavicular region; however, it may sometimes be associated with pain and weakness in the shoulder. We presented a 21-year-old male patient who had pain and weakness in the right shoulder during sportive and daily vigorous activities due to congenital pseudarthrosis of the clavicle. The patient was successfully treated by excision of the ends of the medial and lateral fragments, reconstruction of the defect with a tricortical iliac crest autograft, and internal fixation of the clavicle with a plate and bone screws. After seven months postoperatively, his complaints disappeared, with a full range of motion and Constant score.

Adult↗

PubMed2004

Cr(VI) reduction in aqueous solutions by siderite.

Hexavalent chromium is a common and toxic pollutant in soils and wastewaters. Reduction of the mobile Cr(VI) to less mobile and less toxic Cr(III) is a solution for decontamination of industrial effluents. In this study, the reduction of hexavalent chromium in aqueous solutions by siderite was investigated. The influences of amount of acid, contact time, siderite dosage, initial Cr(VI) concentration, temperature and particle size of siderite have been tested in batch runs. The process was found to be acid, temperature and concentration dependent. The amount of acid is the most effective parameter affecting the Cr(VI) reduction since carbonaceous gangue minerals consume acid by side reactions. The highest Cr(VI) reduction efficiency (100%) occurred in the 50 mg/l Cr(VI) solution containing two times acid with respect to stoichiometric amount of Cr(VI) and at the conditions of siderite dosage 20 g/l, contact time 120 min and temperature 25 degrees C. Reduction efficiency increased with increase in temperature and decrease in particle size. The reduction capacity of siderite was found to be 17 mg-Cr(VI)/g.

Carbonates↗

PubMed2004

Chromium removal from aqueous solution by the ferrite process.

This research summarises the results of the study on the removal of chromium by applying the ferrite process to the solutions obtained from two different Cr(VI) reduction processes utilising sodium sulphite and ferrous sulphate as reducing agents. For both solutions containing trivalent chromium ions, the optimum treatment conditions were determined. The generated sludges were characterised by XRD analysis and physical tests. In addition, to explore the dissolution properties of the sludges obtained, they were contacted with the solutions of sulphuric, citric, tartaric, oxalic and ascorbic acids and EDTA. Also, the sludge samples were subjected to standard toxicity characterisation leaching procedure (TCLP) test of USEPA in order to determine the pollution potential. An efficient Cr(III) removal (about 100%) in the solution from the Cr(VI) reduction process utilising sodium sulphite as reducing agent was achieved when the solution was treated at pH 9 and 50 degrees C for 60 min in the presence of Fe2+/Cr3+ weight ratio of 16. For the other Cr(III) solution prepared from Cr(VI) reduction by ferrous sulphate, a Fe2+/Cr3+ weight ratio of 17.9 at the same conditions was found to produce complete removal of Cr(III). It was determined that the spynel chromium-iron compounds obtained in the process were in the form of chromite (Cr2FeO4). Dissolution experiments and TCLP tests show that the concentrations of the chromium dissolved from both sludges were below the limit given as 5 mg l(-1) by USEPA. The results showed that Cr(III) removal through ferrite process provides the advantages that the sludges generated are non-voluminous, easily separable and environmentally stable.

Chromium↗

PubMed2004

Knee arthrodesis using circular external fixator in the treatment of infected knee prosthesis: case report.

A patient (68 years old and male) underwent total knee replacement because of arthrosis, but he subsequently had infection due to a wound problem. Although he underwent early debridement, antibiotherapy, and soft-tissue operation, treatment failed because of improper soft-tissue coverage and progression of the infection. Therefore, the prosthesis was removed and a spacer with antibiotic was placed, in order to provide soft-tissue coverage and to eradicate infection. After 2 months, the patient underwent knee arthrodesis using a circular external fixator to achieve a stable lower extremity and to facilitate return to activities of daily living. We obtained knee fusion at 4 months without any requirement for secondary procedure of soft tissue and bone graft. There was no major complication. Arthrodesis with circular external fixator is a reliable and successive method that should be preferred for the treatment of infected knee replacement.

Aged↗

PubMed2004

Comparison of basal and clomiphene citrate induced FSH and inhibin B, ovarian volume and antral follicle counts as ovarian reserve tests and predictors of poor ovarian response in IVF.

PURPOSE: To compare basal and clomiphene citrate (CC) induced follicle-stimulating hormone (FSH), estradiol (E2), and inhibin B levels with ultrasound indices of ovarian reserve in infertile women and to test the prognostic value of these tests on response to ovarian stimulation in in vitro fertilization (IVF). METHODS: Fifty-six patients had basal and CC induced serum hormone levels and ultrasound measured mean ovarian volume (MOV) and mean antral follicle counts (MFC). Thirty-two patients were then appropriately selected to have a total of 41 cycles of IVF/ICSI treatment. RESULTS: Women with diminished ovarian reserve had lower MOV, MFC, day 3 and day 10 inhibin B levels (p < 0.001). Only basal and CC induced FSH and inhibin B correlated with MOV and MFC. Poor responders in IVF/ICSI had higher basal FSH (p < 0.05), lower basal and induced inhibin B levels (p < 0.05), and lower MOV and MFC (p < 0.01) than normal responders. Ovarian volume alone was better than age and basal hormones in predicting poor ovarian response, while abnormal CC test was the only independent significant factor in predicting ovarian response. However, age was the only independent predictor of pregnancy in IVF as compared to hormonal and ultrasound indices of ovarian reserve. CONCLUSION: CC test and ovarian volume are better than other hormonal and sonographic tests in predicting the response to ovarian stimulation in IVF cycles.

Adult↗

PubMed2004

A study on dissolution properties of the sludges from Cr(VI) reduction-precipitation processes.

In this article, dissolution characteristics of Cr(VI) reduction-precipitation sludges in the solutions containing mineral acids, organic complexing materials or both are examined. For this purpose, the effects of pH, concentration of complex forming agent and contact time on dissolution of metals from two different sludges obtained by using sodium sulphite and ferrous sulphate as reducing agents are studied. In addition, pollution potentials of the sludges are determined by applying the toxicity tests of TCLP, SPLP, USEPA-1979, and USEPA-19X0. It was found that pH, contact time, concentration and type of complex forming substances are effective parameters on dissolution of metals from the sludges. In mineral acid solutions at pH 3, especially in the presence of organic complexing substances, chromium leached out from hydroxide sludges exceeds the concentration limits of USEPA for hazardous wastes. The amounts of chromium dissolved in the citric and ascorbic acid solutions and the amount of iron dissolved in the EDTA solution were found to be higher than in the other test solutions. Also, TCLP test shows that chromium hydroxide sludge obtained from sulphite reduction precipitation process of Cr(VI) is a potential hazardous solid. According to the results of this study, considering the probable presence of complexing agents in the disposal sites, toxicity test methods should be modified.

Carcinogens, Environmental↗

PubMed2004

[The chondroprotective effect of intra-articular hyaluronic acid at early stages of osteoarthritis: an experimental study in rabbits].

OBJECTIVES: Hyaluronic acid (HA) is used in osteoarthritis, especially for the control of pain. In this study, we investigated the effect of intra-articular HA on experimental osteoarthritis of early stage. METHODS: Osteoarthritis was induced in both knees of 10 rabbits by transecting the anterior cruciate ligament under intramuscular anesthesia with ketamine and xylazine. Intra-articular HA at a dose of 0.6 ml (15 mg/ml) and physiologic saline solution (0.6 ml) were injected into the right and left knees, respectively, three times with a week interval. Three rabbits died during the study period and were excluded. The remaining rabbits were sacrificed in the 12th week via high dose anesthesia to remove the distal femora for histological evaluation using the Mankin scale and for measurements of the cartilage area. RESULTS: The mean cartilage areas calculated in HA- and saline-injected knees differed significantly (1.097 mm2 and 0.477 mm2, respectively; p<0.05). The overall mean Mankin score was significantly lower in HA-injected knees (3.57 versus 11.14; p<0.05). Although, there were no significant differences between the two groups with respect to cellular abnormality, matrix staining, and tidemark continuity (p>0.05), the mean scores for the structure of the cartilage were significantly different (0.86 versus 4.43; p<0.05). The integrity of the tidemark was preserved in all the HA-administered knees, though a notable disruption was observed in four control knees. CONCLUSION: Our results suggest that HA delays the development of osteoarthritis at early stages through exerting a chondroprotective effect.

Adjuvants, Immunologic↗