Biomechanical Properties and Biocompatibility of Implant-Supported Full Arch Fixed Prosthesis Substructural Materials.

OBJECTIVES: The purpose of this study was to investigate the fracture resistance, biocompatibility, hardness, and transverse strength of non-precious metal alloy (chromium-cobalt; Cr-Co), titanium (Ti), zirconia (Zr), polymethylmethacrylate (PMMA), and polyetheretherketone (PEEK) when employed as substructure materials according to the implant supported full arch fixed prosthesis treatment concept. MATERIALS AND METHODS: In total, 150 Cr-Co, Ti, Zr, PMMA, and PEEK samples (n = 30 per material) measuring 25 × 2 × 2 mm in size were produced. Of the samples, 50 (n = 10 for each material, all having dimensions of 6 × 3 mm) were subjected to biocompatibility tests. The Vickers hardness test and three-point bending test were performed; fracture resistance measurements were taken and the biocompatibility of the samples was evaluated by the XTT assay. RESULTS: Vickers hardness was highest for Zr (p < 0.05). PEEK and PMMA had the lowest (and similar) fracture resistance values (p < 0.05). Cell proliferation on the surfaces of the materials was similar between PEEK and Zr (p > 0.05), which were the most biocompatible materials. CONCLUSIONS: Within the limitations of this study, the most favorable materials in terms of biocompatibility were found as PEEK and Zr. When biomechanical properties are evaluated, the most durable materials can be specified as Cr-Co and Zr. Also, further studies are needed to improve material stability.

The Effect of the iNOS Inhibitor S-Methylisothiourea and Hyperbaric Oxygen Treatment on Radiation Colitis in Rats.

INTRODUCTION: External radiotherapy is one of the main treatment modalities for a variety of malignancies. However, the lower gastrointestinal tract is sensitive to the ionizing radiation. Hyperbaric oxygen treatment (HOT) has been suggested as a viable treatment for refractory radiation colitis, but the effect of S-Methylisothiourea (SMT) in the radiation colitis have not reported. To investigate the effect of SMT, HOT and the combination of both in an acute radiation-induced enterocolitis model. METHODS: Sixty Sprague-Dawley rats were divided randomly into five equal groups. A single dose of gamma irradiation (25 Gy) was administered through the colorectal region to anesthetized rats. In the control group, we applied 2 ml of saline solution intraperitoneally for five days. In the HOT group, 100-per-cent oxygen at 2.5 atm pressure was applied for five days. In the SMT group, 10 mg/kg/day of SMT was applied intraperitoneally for five days. In the HOT+SMT group, HOT and SMT were both applied in the same dosages as in the preceding two groups. At the end of five days, the rats were sacrificed and colon samples were collected for histological grading. Blood samples were collected to test for : tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), IL-1ß, transforming growth factor-ß (TGF-ß) and intercellular adhesion molecule-1 (ICAM-1) mRNA. RESULTS: The TNF-α, IL-1ß, IL-10 and TGF-ß levels were reduced by SMT, HOT and HOT+SMT applications (p < 0.05). However ICAM-1 mRNA levels were not significantly lower (p:0.19). The microscopic scores differed significantly between the SMT, HOT and HOT+SMT groups and the control group. There was significant improvement histologically, especially in the HOT+SMT group. When we compared the weight of the rats before and after the study, weight loss was significantly lower in the SMT, HOT and HOT+SMT groups compared with the control group (p < 0.05). CONCLUSION: HOT and SMT together were significantly more effective in preventing weight loss and in reducing inflammation and the severity of colitis histology when compared with HOT and SMT separately.

The diagnosis of common variable immunodeficiency in adults should not be missed: A delayed diagnosis can be devastating

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Unusual localization of a primary hydatid cyst: a subcutaneous mass in the paraumbilical region.

Hydatid cyst disease caused by Echinoccus granulosus is not a rare disease and mostly localized in liver and lung. The localization of the disease in the subcutaneous paraumbilical region without any other organ involvement is a unique existence that we present. A 63-year-old Turkish male complaining of abdominal distention and pain had an abdominal mass for one year. When the patient came to our Clinic, we detected a 4x5 cm mass in the left quadrant- paraumbilical region by using ultrasonography. Complete surgical resection of the mass was performed with uneventful post-operative recovery. Histopathological examination of the surgical specimen demonstrated a multive-sicular hydatid cyst. When a subcutaneous cystic mass is detected in a patient, regarding the region where he lives and endemicity, hydatid cyst should be considered.

Early postoperative hemodynamic performances of stented versus stentless aortic xenografts in aortic valve replacement in elderly patients: a comparative study.

BACKGROUND AND AIM: Surgical valve replacement is the most commonly performed for aortic stenosis. Randomized trials comparing stentless to stented bioprostheses for aortic valve replacement in elderly are scarce. The aim of our study was comparing and evaluating the early hemodynamic performances of Hancock™ stented and FreeStyle™ stentless xenograft aortic valves in aortic valve replacement in elderly patients. PATIENTS AND METHODS: The study involved 40 patients (27 females and 13 males) older than 75 years old. The study was done during the postoperative period. Aortic valve replacements of stented and stentless xenografts were performed to the patients in Group I and Group II, respectively. Investigations for the echocardiographic results were completed on the postoperative 8-10th days. Parameters for the evaluation of hemodynamics were peak pressure gradient, mean pressure gradient and effective orifice area. The parameters were calculated with Doppler echocardiography by using specific formulas. RESULTS: Peak pressure gradients in patients with stented valves were significantly higher than in stentless valves [Stented valve group 32.45 ± 7.58 vs Stentless valve group 21.50 ± 4.77 mmHg] (p < 0.05). Mean pressure gradients were found to be significantly higher in stented group compared with stented group [Stented valve group 11.050 ± 3.2521 vs Stentless valve group 19.350 ± 6.6036 mmHg] (p < 0.05). The effective orifice area index of implanted valve was significantly greater in the stentless group, as well [Stentless valve group 2.5050 ± 0.6022 vs Stented valve group 1.3050 ± 0.3316 cm2] (p < 0.05). CONCLUSIONS: In early postoperative period, effective orifice areas and pressure gradients were found higher in stentless valve group.

Antitumor effects of Origanum acutidens extracts on human breast cancer.

PURPOSE: There has been a long-standing interest in the identification of medicinal plants and derived natural products for developing anticancer agents. This work aimed at investigating the antiprolipherative properties of Origanum acutidens (OA) on breast cancer. METHODS: OA water extracts were studied for cytotoxicity against the breast cancer cell lines MCF-7, MDA-MB-468 and MDA-MB-231. In vitro apoptosis studies of these cancer cell lines were performed by annexin V staining in flow cytometry analyses. Immunohistochemistry studies for Ki-67 and caspase-7 of tumor tissue sections of dimethylbenzanthracene (DMBA) -induced mammary cancer in rats were also performed. TUNEL assay was used to detect apoptotic cells of tumor tissue. In vivo anticancer activity testing was carried out by inhibiting the growth of DMBA-induced mammary cancer in rats. RESULTS: OA showed cytotoxicity on all 3 cancer cell lines. Annexin-positive cells level in OA-treated cell lines were significantly higher compared with untreated control cells (p=0.002). The expressions of caspase-7 protein and TUNEL-positive cells were much higher for the rats treated by OA, compared with the untreated control group (p<0.05). The expressions of the Ki-67 decreased in the treated groups compared with the control group (p<0.05). In vivo studies showed that the mean tumor volume inhibition ratio in OA-treated group was 41 % compared with the untreated rats (p<0.05). CONCLUSION: These results indicate that OA has antitumor activity against breast cancer cell lines.