ABSTRACT
OBJECTIVE: Although apolipoprotein (APOE) ε4 allele is a well-established risk factor for late-onset Alzheimer disease (AD), the mechanism of its effects on AD pathogenesis is not fully understood. We aimed to investigate the effects of APOE genotype on regional cerebral glucose metabolism in cognitively normal (CN) elderly. We further tried to elucidate whether or not such effects are associated with beta-amyloid protein (Aß) deposition. METHODS: 31 CN elderly participants underwent clinical examination, a range of neuropsychological tests, APOE genotyping, and Pittsburgh compound-B- and fluorodeoxyglucose-PET scans. RESULTS: 17 APOE ε4 carriers and 15 non-carriers were included. Both hypometabolic and hypermetabolic regions were observed in ε4 carriers compared with noncarriers when age, education, and sex were controlled. When the degree of global cerebral Aß deposition was adjusted, the hypometabolic regions in the temporo-parietal area (i.e., BA 22 and 39) largely disappeared, whereas the hypermetabolic regions persisted in medial frontal and anterior temporal areas (i.e., BA 38, 11, and 39). Behaviorally, verbal episodic memory scores of APOE ε4 carriers were slightly lower than those of noncarriers, though still within normal range. CONCLUSIONS: Our findings indicate that decreased cerebral glucose metabolism in the temporoparietal junction associated with APOE ε4 in CN elderly appears to be mediated by Aß deposition, and the effect of APOE ε4 on hypermetabolism in the frontal and anterior temporal regions is independent of Aß and may be associated with presence of compensatory mechanism in CN elderly with the ε4 allele.
Subject(s)
Aging/genetics , Amyloid beta-Peptides/metabolism , Apolipoprotein E4/genetics , Cerebral Cortex/metabolism , Cognition , Aged , Alzheimer Disease/genetics , Aniline Compounds , Female , Fluorodeoxyglucose F18 , Functional Neuroimaging , Genotype , Glucose/metabolism , Humans , Male , Memory, Episodic , Neuropsychological Tests , Positron-Emission Tomography , ThiazolesABSTRACT
BACKGROUND AND AIM: The aim of the present study was to investigate the clinical effectiveness, safety, and outcome associated with the use of covered expandable Nitinol stents (Taewoong Medical, Seoul, Korea) for the treatment of malignant gastroduodenal obstructions. METHODS: Between March 2001 and October 2004, covered expandable Nitinol stents were placed in 68 consecutive patients under endoscopic and fluoroscopic guidance for the following reasons: gastric carcinoma (n = 49), recurrent carcinoma after partial gastrectomy (n = 7), or another malignant neoplasm involving the duodenum (n = 12). RESULTS: Technical success was achieved in 60 of the 68 patients (88.2%). After stent placement, mean dysphagia score improved from a mean of 3.5 to 1.2 (P < 0.001). The mean period of primary stent patency was 107.2 days. During follow up (mean 4.4 months; range, 1-15 months), major complications (migration [6], bleeding [3], perforation [1], ingrowth [1], overgrowth [7], fistula [1]) occurred in 19 patients (27.9%), and stent migration occurred in six (8.8%) (proximal migration into the stomach [n = 3], or distal migration [n = 3]). Recurrent dysphagia (mainly due to tumor ingrowth/overgrowth) occurred in eight patients (11.8%). CONCLUSION: Covered expandable Nitinol stents appear to offer an effective and feasible palliative therapy in patients with a malignant gastroduodenal obstruction.
