Reelin and APP Cooperatively Modulate Dendritic Spine Formation In Vitro and In Vivo

Amyloid precursor protein (APP) plays an important role in the pathogenesis of Alzheimer’s disease (AD), but the normal function of APP at synapses is poorly understood. We and others have found that APP interacts with Reelin and that each protein is individually important for dendritic spine formation, which is associated with learning and memory, in vitro. However, whether Reelin acts through APP to modulate dendritic spine formation or synaptic function remains unknown. In the present study, we found that Reelin treatment significantly increased dendritic spine density and PSD-95 puncta number in primary hippocampal neurons. An examination of the molecular mechanisms by which Reelin regulates dendritic spinogenesis revealed that Reelin enhanced hippocampal dendritic spine formation in a Ras/ERK/CREB signaling-dependent manner. Interestingly, Reelin did not increase dendritic spine number in primary hippocampal neurons when APP expression was reduced or in vivo in APP knockout (KO) mice. Taken together, our data are the first to demonstrate that Reelin acts cooperatively with APP to modulate dendritic spine formation and suggest that normal APP function is critical for Reelin-mediated dendritic spinogenesis at synapses.

The Effect of Embolotherapy for Acute Gastrointestinal Bleeding in Patient with Coagulopathy

PURPOSE: To analyse the causes of coagulopathy and determine the effect of embolotherapy on acute gastrointestinal(GI) bleeding coexisting with coagulopathy. MATERIALS AND METHODS: Between June 1991 and December 1998, 29 patients with acute GI bleeding (M:F =21:8, mean age, 57.8 years) underwent percutaneous embolotherapy and immediate cessation of bleeding was confirmed. The patients were divided into two groups: control (n =16) and those with coagulopathy (n =13), group membership being determined according to the criteria of >+/-2SD of normal prothrombin time (PT) and activated partial thromboplastin time (aPTT) ( PT >23 seconds, aPTT >40 seconds) at the time at which embolization was requested. Embolotherapy was, defined as clinically successful, if the patient was stable for at least three days, without bleeding, after technically successful embolization. The clinical success rate of embolization and the mortality rate were compared between the two groups, and the causes of coagulopathy statistically analysed. RESULTS: The clinical success rate of embolization was 75% (n =12) in the control group, compared with 38.5% (n =5) in the coagulopathic group (p < 0.05), while the mortality rate for the two groups was 6.3% (n =1) and 53.8% (n =7), respectively (p < 0.005). Statistically, massive transfusion and sustained shock before embolization were the causes of coagulopathy (p < 0.05). CONCLUSION: In coagulopathic patients with acute GI bleeding, embolotherapy induces transient bleeding control, but is unlikely to save lives.

MRI of Vertebral Compression Fracture: Benign versus Metastasis

PURPOSE: This study was performed to evaluate differentiating features of spinal compression fractures between benign and metastatic lesions. MATERIALS AND METHODS: We reviewed MR imaging in 52 patients (benign 38, metastasis 14) with vertebral compression fracture. Signal intensity of fracture and uninvolved areas, presence of contrast enhancement, fragmentation, and paravertebral mass were analyzed retrospectively. RESULTS: Signal intensity of fracture site was variable in benign lesions, but low signal intensity on T1-weighted image and high on T2*-weighted image were seen in all cases of metastasis. Signal intensity of uninvolved area was high on T1-weighted image and low on T2*-weighted image in 84% of benign lesions. On the contrary, normal marrow signal intensity was not seen in the uninvolved areas of all metastatic fractures. Contrast enhancement were observed in all cases of benign & metastatic compression fractures. Fragmentation were seen in 1 case of metastasis(7%) and in 11 cases of benign lesions(29%). Paravertebral mass were seen in 5 cases of metastasis(36%) and in 7 cases of benign lesions(18%). CONCLUSION: Presence of normal marrow signal intensity in the uninvolved area of fracture site could be the most useful sign for differentiating benign causes from metastasis.

Multiple Bile-duct Hamartoma: Two Case Report

Authors report the radiologic findings of two cases of multiple bile-duct hamartoma in the liver. Ultrasonography and computed tomography of the liver were performed in two female patients. In one patient, ERCP was performed. Ultrasonography and computed tomography showed scattered multiple hypoechoic and low attenuated lesions, measuring up to 2cm in both lobe and ERCP showed communication of these lesions with the biliary system. Multiple bile-duct hamartoma should be included in the differential diagnosis of multiple small cystic lesions in the liver.