GD3 Accumulation in Cell Surface Lipid Rafts Prior to Mitochondrial Targeting Contributes to Amyloid-beta-induced Apoptosis

Neuronal apoptosis induced by amyloid beta-peptide (A beta) plays an important role in the pathophysiology of Alzheimer's disease (AD). However, the molecular mechanism underlying A beta-induced apoptosis remains undetermined. The disialoganglioside GD3 involves ceramide-, Fas- and TNF-alpha-mediated apoptosis in lymphoid cells and hepatocytes. Although the implication of GD3 has been suggested, the precise role of GD3 in A beta-induced apoptosis is still unclear. Here, we investsigated the changes of GD3 metabolism and characterized the distribution and trafficking of GD3 during A beta-induced apoptosis using human brain-derived TE671 cells. Extracellular A beta induced apoptosis in a mitochondrial-dependent manner. GD3 level was negligible in the basal condition. However, in response to extracellular A beta, both the expression of GD3 synthase mRNA and the intracellular GD3 level were dramatically increased. Neosynthesized GD3 rapidly accumulated in cell surface lipid microdomains, and was then translocated to mitochondria to execute the apoptosis. Disruption of membrane lipid microdomains with methyl-beta-cyclodextrin significantly prevented both GD3 accumulation in cell surface and A beta-induced apoptosis. Our data suggest that rapidly accumulated GD3 in plasma membrane lipid microdomains prior to mitochondrial translocation is one of the key events in A beta-induced apoptosis.

Treatment of the Acetabular Fracture / 대한정형외과학회잡지

Fractures of the acetabulum are relatively uncommon, but because they involve a major weight bearing joint in the low extremity, they assume great clincal importance. The principle of management for this fracture is as for any other displaced intra-articular fracture, nsmely that anstomical reduction is essential for good long term function of the obtained by closed means, but more often, open reduction followed stable internsl fixation allowing early active or passive motion will be required. In the past, the achievement of this ideal, that is anatomical reduction, has been difficult because technical problems such as those caused by complicated anatomy, difficulty with surgical exposure, severe comminution in many cases, and major associated injuries. We classified the acetabular fractures of 71 patients with 72 hips from 1980 to 1987 and clinical analysis was performed on 51 hips allowing the possible follow-up evaluation beyond the 12 months. Following results were obtained. 1. The most common associated injury was the pelvic bone fracture(25.5%). 2. The most common types of fracture on each classification were posterior wall fracture in Letournel(37.5%), posterior acetabular fracture in Rowe & Lowell(42.3%), central fracture- dislocation without involving of weight bearing dome of acetabulum in Carnesale(23.9%). 3. According to calssification method, the interpretation for characteristics of fracture type and frequency of acetabular fracture was very different each other. 4. The Leournels classification was relatively simple and could contain with many types of fracture and was helpful to determine the index of treatment. 5. The prognosis of linear undisplaced fracture and posterior fracture was better than acetabular medial, superior and bursting fracture in both conservative and operative treatment. 6. The posterior wall fracture with widely displaced fracture or joint instability, acetabular dome fracture, intraarticular fragment was absolute indication for operative treatment. 7. The treatment result and prognosis was influenced to the accurate classification of fracture type, anatomical reduction and rigid internal fixation.

A Study on the Tilting of the Normal Korean Adult Pelvis / 대한정형외과학회잡지

In the standing lateral position, the pelvis is tilted in some degree anteroinferiorly. But there was no accurate and standard measurement about the pelvis tilting. The pelvis tilting affects on the lumbar lordosis, weight bearing area of the hip joint, and the anteversion of acetabulum. In the standing true lateral view of the pelvis, 5 points were marked: midpoint of both anterosuperior iliac spines (M), upper margin of symphysis pubis (S), lower margin of symphysis pubis(S), sacral promontorium (SP), coccyx tip (C). And using the additional horizontal plane (H), we measured the 4 angles : angle I ( < MSH), angle II ( < SPSH), angle III(

Supracondylar Fracture of the Humerus in Children: Part I : Extension / 대한정형외과학회잡지

The authors made an attempt to classify the supracondylar extension-valgus fracture according to the direction and location of the fracture line based on the radiographic manifestation. This new classification helps to dictate the model of treatment, possible sequence of reduction and the causes of deformity of the elbow after treatment. During the last 12 years of this study, 200 supracondylar fractures of the humerus were treated in the Kyung Hee University Hospital. Of the cases 82 were extension-valgus fractures. The results were as follows: 1. The supracondylar extension-valgus fracture were classified into 5 types: Type I: fish-tail fracture (14 cases) Type II : obtuse fish-tail fracture (27 cases) Type III: oblique fracture (16 cases) Type IV: oblique fracture with comminution of lateral column (14 cases) Type V: Transverse fracture (11 cases) 2. The displacement of the distal fragment in the fish-tail fracture is severe but it can be reduced easily by manipulation. Once reduction has been obtained, the fracture is stable and maintained by a long arm cast with acute flexion of the elbow alone. There is no need of percutaneous pinning. Among 14 cases of type I fracture there was no cubitus varus deformity. 3. The line of the obtuse fish-tail fracture lies distal to fish-tail fracture. This is unstable so it is necessary to percutaneous pinning. 4. The oblique fracture is produced by the hyperextension of the elbow and degrees of the obliquity of the fracture line were 12 to 20 degrees (Av. 14 degrees). The valgus angles in opposit elbows were 9 to 25 degrees (Av. 16 degrees). The forearm must be pulled into valgus position during the reduction of the fracture. 5. Type IV fracture occures under 4 years old, and more commonly in girls. This is unstable, so it is necessary to percutaneous pinning.