Screw shaped implants of Titanium-13Zirconium-6Niobium(newly developed), Titanium-6Zirconium-6Sn-6Niobium(newly developed) and Titanium-6Aluminum-4Vanadium were machined with square top and inserted in rabbit bone for 3 months. Biomechanical tests(removal torque) showed Titanium-13Zirconium-6Niobium and Titanium-6Zirconium-6Sn-6Niobium to be more stable in the bone bed than those of Titanium-6Aluminum-4Vanadium. Titanium-13Zirconium-6Niobium implants demonstrated a mean removal torque of 31.59Ncm while Titanium-6Aluminum-4Vanadium demonstrated a mean removal torque of 25.27Ncm and Titanium-6Zirconium-6Sn-6Niobium revealed a mean removal torque of 37.44Ncm and were statistically significance in Wilcoxon Signed Rank test(P<0.05). Histomorphometrical comparisons were performed on 10 micrometer thick undecalcified ground sections in the light microscope and Titanium-13Zirconium-6Niobium showed more mean bone-to-metal contact ratio than to other two titanium alloys but had no statistically significant differences were found among the three materials(P>0.01).
Alloys* ; Titanium* ; Torque

Finite element analyses were performed to study effects on stress distribution generated in jaw bone for various shapes of dental implants: plateau type, plateau with small radius of curvature, triangular thread screw type in accordance with ISO regulations and square thread screw filleted with small radius partially. It was found that square thread screw filleted with small radius was more effective on stress distribution than other dental implants used in analyses. Additional analyses were performed on the implant with square thread screw filleted with small radius for verying design parameters, such as the width of thread end, the height of the thread of the implant and load direction, to determine the optimum dimensions of the implant. The highest stress concentration occurred at the region in jaw bone adjacent to the first thread of the implant. The maximum effective stress induced by a 15 degree oblique load of 100 N was twice as high as the maximum effective stress caused by an equal amount of vertical load. Stress distribution was more effective in the case when the width of thread end and the height of thread were p/2 and 0.46p, respectively, where p is the pitch of thread. At last, using tensile force calculated from the possible insert torque without breading bone thread, finite element analysis was performed on the implant to calculate pre-stress when the primary fixation of the implant was operated in jaw bone. The maximum effective stress was 136.8 MPa which proven to be safe.
Bread ; Dental Implants ; Finite Element Analysis ; Jaw ; Radius ; Social Control, Formal ; Torque

PURPOSE: In this study, brazing characteristics of ZrO2 and Ti-6Al-4V brazed joints with increasing temperature were investigated. MATERIALS AND METHODS: The sample size of the ZrO2 was 3 mm x 3 mm x 3 mm (thickness), and Ti-6Al-4V was 10 mm (diameter) x 5 mm (thickness). The filler metal consisted of Ag-Cu-Sn-Ti was prepared in powder form. The brazing sample was heated in a vacuum furnace under 5 x 10(-6) torr atmosphere, while the brazing temperature was changed from 700 to 800degrees C for 30 min. RESULTS: The experimental results shows that brazed joint of ZrO2 and Ti-6Al-4V occurred at 700 - 800degrees C. Brazed joint consisted of Ag-rich matrix and Cu-rich phase. A Cu-Ti intermetallic compounds and a Ti-Sn-Cu-Ag alloy were produced along the Ti-6Al-4V bonded interface. Thickness of the reacted layer along the Ti-6Al-4V bonded interface was increased with brazing temperature. Defect ratios of ZrO2 and Ti-6Al-4V bonded interfaces decreased with brazing temperature. CONCLUSION: Thickness and defect ratio of brazed joints were decreased with increasing temperature. Zirconia was not wetting with filler metal, because the reaction between ZrO2 and Ti did not occur enough.
Alloys ; Atmosphere ; Dental Implants ; Hot Temperature ; Joints ; Sample Size ; Titanium ; Vacuum ; Zirconium

The cause of Parkinson’s disease has been traditionally believed to be the dopaminergic neuronal death in the substantia nigra pars compacta (SNpc).This traditional view has been recently challenged by the proposal that reactive astrocytes serve as key players in the pathology of Parkinson’s disease through excessive GABA release. This aberrant astrocytic GABA is synthesized by the enzymatic action of monoamine oxidase B (MAOB), whose pharmacological inhibition and gene-silencing are reported to significantly alleviate parkinsonian motor symptoms in animal models of Parkinson’s disease. However, whether genetic ablation and over-expression of MAOB can bidirectionally regulate parkinsonian motor symptoms has not been tested. Here we demonstrate that genetic ablation of MAOB blocks the MPTP-induced augmentation of astrocytic GABA-mediated tonic inhibition of neighboring dopaminergic neurons as well as parkinsonian motor symptoms, indicating the necessity of MAOB for parkinsonian motor symptoms. Furthermore, we demonstrate that GFAP-MAOB transgenic mice, in which MAOB is over-expressed under the GFAP promoter for astrocyte-specific over-expression, display exacerbated MPTP-induced tonic inhibition and parkinsonian motor symptoms compared to wild-type mice, indicating the importance of astrocytic MAOB for parkinsonian motor symptoms. Our study provides genetic pieces of evidence for the causal link between the pathological role of astrocytic MAOB-dependent tonic GABA synthesis and parkinsonian motor symptoms.

The cause of Parkinson’s disease has been traditionally believed to be the dopaminergic neuronal death in the substantia nigra pars compacta (SNpc).This traditional view has been recently challenged by the proposal that reactive astrocytes serve as key players in the pathology of Parkinson’s disease through excessive GABA release. This aberrant astrocytic GABA is synthesized by the enzymatic action of monoamine oxidase B (MAOB), whose pharmacological inhibition and gene-silencing are reported to significantly alleviate parkinsonian motor symptoms in animal models of Parkinson’s disease. However, whether genetic ablation and over-expression of MAOB can bidirectionally regulate parkinsonian motor symptoms has not been tested. Here we demonstrate that genetic ablation of MAOB blocks the MPTP-induced augmentation of astrocytic GABA-mediated tonic inhibition of neighboring dopaminergic neurons as well as parkinsonian motor symptoms, indicating the necessity of MAOB for parkinsonian motor symptoms. Furthermore, we demonstrate that GFAP-MAOB transgenic mice, in which MAOB is over-expressed under the GFAP promoter for astrocyte-specific over-expression, display exacerbated MPTP-induced tonic inhibition and parkinsonian motor symptoms compared to wild-type mice, indicating the importance of astrocytic MAOB for parkinsonian motor symptoms. Our study provides genetic pieces of evidence for the causal link between the pathological role of astrocytic MAOB-dependent tonic GABA synthesis and parkinsonian motor symptoms.

No abstract available.
Bleomycin* ; Lymphangioma, Cystic*

All-trans retinoic acid (ATRA) is the standard induction treatment for acute promyelocytic leukemia (APL). Quite many ATRA-related side effects, including retinoic acid syndrome, were reported. So far, it has rarely been reported that Sweet's syndrome, characterized by fever, neutrophilia, painful erythematous cutaneous plaques, dense dermal infiltrates of mature neutrophils and rapid response to steroid therapy, is associated with ATRA. In the case that Sweet's syndrome associated with ATRA is found, physicians will have to face a great challenge over the possibility of infectious conditions. We present here a case of Sweet's syndrome associated with ATRA. A 35-year-old female with APL developed fever, painful erythematous cutaneous plaques on both cheeks, right wrist and both shins during induction chemotherapy with ATRA. A skin biopsy revealed a dense dermal infiltrate, consisting of mature neutrophils without vasculitis or cutaneous immunoglobulin deposits, which is compatible with Sweet's syndrome. Oral prednisone was administered and the lesions started to improve within 48 hours
Adult ; Biopsy, Needle ; Case Report ; Female ; Follow-Up Studies ; Human ; Leukemia, Promyelocytic, Acute/diagnosis/*drug therapy ; Prednisone/administration & dosage ; Risk Assessment ; Sweet's Syndrome/*chemically induced/drug therapy/*pathology ; Tretinoin/*adverse effects/therapeutic use

No abstract available.

No abstract available.

No abstract available.
Osteoblasts* ; PPAR gamma