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Interbody fusion cage surgery with discectomy has been the major surgical method for treating back pain and degenerative diseases. However, highly rigid fusion devices cause great concentrations of mechanical stress, engendering stress concentration effects. In this study, various geometric structures with single porosity and gradient porosity were designed and 3D printed with selective laser melting. ANSYS software was applied to analyze the stress and strain distributions for different motion modes. For a disc fusion cage comprising three concentric rings surrounding a solid cylinder, with gradient porosity values of 60%-70%-80%-solid (from outside to inside), both the stress and strain showed closer agreement with the intervertebral disc stress and strain. Both the cage and the disc exhibited uniform stress distributions with bone, which would be able to avoid stress concentration. The patterns of the designed models were then printed using Ti-6Al-4V powders. The morphologies of the printed porous structures were examined by optical microscopy and scanning electron microscopy. The porosities of the printed specimens were investigated using the Archimedes method. The results revealed only minor geometric deviation between the computer-aided design patterns and the as-printed samples. [ABSTRACT FROM AUTHOR]

Multiple symmetric lipomatosis (MSL; Madelung disease) is an uncommon disorder with diffuse multiple symmetrical unencapsulated accumulations of fat located in the neck and the upper trunk. MSL usually occurs in middle aged Caucasian men of Mediterranean ancestry with a history of alcoholism. In the past decade, an increasing number of cases in the Chinese population have been reported which appear to be limited to the head and neck regions. We describe two Chinese patients with MSL who have a history of alcoholism. The MR and CT findings disclosed that one patient had the typical accumulation of unencapsulated fat in the neck and upper back, while the other patient had more than the typical neck involvement and an unusual distribution of fat in the scrotum.

Aim: To study the effect of copper transporting P-type ATPase in copper metabolism of hepatocyte and pathogenesis of Wilson disease (WD)., Methods: WD copper transporting properties in some organelles of the cultured hepatocytes were studied from WD patients and normal controls.These cultured hepatocytes were incubated in the media of copper 15 mg x L(-1) only, copper 15 mg x L(-1) with vincristine (agonist of P-type ATPase) 0.5mg x L(-1), or copper 15 mg x L(-1) with vanadate (antagonist of P-type ATPase) 18.39 mg x L(-1) separately. Microsome (endoplasmic reticulum and Golgi apparatus), lysosome, mitochondria, and cytosol were isolated by differential centrifugation. Copper contents in these organelles were measured with atomic absorption spectrophotometer, and the influence in copper transportion of these organelles by vanadate and vincristine were comparatively analyzed between WD patients and controls. WD copper transporting P-type ATPase was detected by SDS-PAGE in conjunction with Western blot in liver samples of WD patients and controls., Results: The specific WD proteins (M(r)155,000 lanes) were expressed in human hepatocytes, including the control and WD patients. After incubation with medium containing copper for 2 h or 24 h, the microsome copper concentration in WD patients was obviously lower than that of controls, and the addition of vanadate or vincristine would change the copper transporting of microsomes obviously. When incubated with vincristine, levels of copper in microsome were significantly increased, while incubated with vanadate, the copper concentrations in microsome were obviously decreased. The results indicated that there were WD proteins, the copper transportion P-type ATPase in the microsome of hepatocytes. WD patients possessed abnormal copper transporting function of WD protein in the microsome, and the agonist might correct the defect of copper transportion by promoting the activity of copper transportion P-type ATPase., Conclusion: Copper transportion P-type ATPase plays an important role in hepatocytic copper metabolism. Dysfunction of hepatocytic WD protein copper transportion might be one of the most important factors for WD.