Amyloid precursor protein processing in Alzheimer's disease

Alzheimer's disease [AD] is a progressive neurodegenerative disorder and a leading cause of dementia. The AD is characterized by presence of intraneuronal tangles and extracellular plaques in the brain. The plaques are composed of dense and mostly insoluble deposits of amyloid beta peptide [A beta], formed by sequential cleavage of the Amyloid Precursor Protein [APP], by two pathways amyloidogenic and non-amyloidogenic. Tangles are composed of paired helical fragments, which aggregate to form, microtubular protein tau. Although A beta plaques are established to be the cause of the disease, there exist genetic factors and other pathological identifications in addition to these which are an integral part of the disease. This article gives an overview into the mechanism of APP action, genetic factors and other pathological identifications contributing to Alzheimer's disease formation

A study on the imaging characteristics of autoimmune pancreatitis / 中华普通外科杂志

ObjectiveTo investigate the CT and MRI imaging characteristics of autoimmune pancreatitis and its clinical value.MethodsFourteen patients(13males, 1female, mean age 58.3 years) with autoimmune pancreatitis proved histopathologically or clinically were enrolled in the study.Clinical data was studied retrospectively.Among those patients,CT was performed on 12 cases and MR imaging was performed on 8 patients,6 patients underwent both CT and MR imaging.ResultsAll 14 patients had enlargement of the pancreas,which could be divided into three types including diffuse type ( n =7 ),focal type ( n =5 ) and mixed type ( n =2 ).On plain CT the pancreas was of isodensity ( n =5 ) or mild hypodensity ( n =7).In one case there was several small hypodensity cystic lesions within and around the pancreas that was rarely seen in other autoimmune pancreatitis cases.Pancreatic lesions as shown by MRI were all mildly hypointense on T1WI and mildly hyperintense on T2WI,all displayed lesions were detected as high-signal intensity areas on DWI. By medium contrast,autoimmune pancreatitis lesions demonstrated “ snow-like” heterogeneously decreased enhancement on artery phase of dynamic contrast enhanced imaging and then showed gradually delayed enhancement on portal venous phase and later phases.“Capsule-like” rim was present around the autoimmune pancreatitis lesions in 9 cases.Main pancreatic duct was irregular in shape in 4 cases and slightly dilated in 5 patients.Strictures of lower common bile duct and upper bile duct dilatation as well as thickening and enhancement of the bile duct wall were found in 9 cases.Peripheral vascular involvement was seen in 4 cases. Abdominal lymphadenopathy at hepatic portal was observed in 1 patient.Two cases showed tiny decreased enhancement lesions in the kidneys.Steroid therapy was given in 10 cases,all pancreatitis lesions ameliorated as showed by follow-up imaging examinations.ConclusionsAIP specific CT and MRI imaging findings are common in most patients which help establish the diagnosis and differential diagnosis of AIP.

MDCT findings and characteristics of metastatic pancreatic tumors / 中华胰腺病杂志

Objective To evaluate MDCT findings and characteristics of metastatic pancreatic tumors. Methods A total of 23 cases with metastatic pancreatic tumors were collected and the CT findings including the size, number, location, density patterns, enhancement patterns and secondary signs (dilatation of the pancreatic duct and/or bile duct, involvement of peripancreatic vessels, atrophy of distal pancreas) were analyzed retrospectively. Results A total of 35 metastatic pancreatic tumors were identified in the 23 patients. Tumors were multiple in 7 patients, the other 16 patients had single metastatic pancreatic tumor. The mean maximum diameter of the tumors was 3. 3 cm; the majority was located in the pancreatic body/tail. Thirty tumors demonstrated no enhancement in the arterial phase, and in the portal phase 23 tumors were hypodensive compared with normal pancreatic tissue, 4 tumors were isodense and 3 tumors showed a peripheral rim of enhancement. Five tumors showed markedly enhancement in the arterial and portal phase. Only 1 patients had dilated biliary and pancreatic duct, and 2 patients had dilated pancreatic duct. Only 1 case demonstrated involvement of splenic vein. 13 of the 23 patients had extra-pancreatic metastasis. Conclusions Pancreatic metastasis showed certain imaging characteristics. The accuracy of CT diagnosis could be improved by understanding of these CT findings and clinical features.

CT findings of pancreatic mucinous neopalsms / 中华放射学杂志

Objective To analyze the CT appearances with pathologic correlation and improve the recognition of pancreatic mucinous cystadenoma/cystadenocarcinoma.Methods CT findings in 20 patients with pathologically proven pancreatic mucinous cystic tumor were retrospectively and jointly reviewed by two observers blinded to the pathological results.All patients underwent precontrast and postcontrast helical CT.The number,size,location,and margins of the lesions were observed,along with wall thickness,septation,calcification witllin the lesions.and presence of mural nodules and their enhancement.The findings of malignant and benign tumors were compared.Results Twelve cases of mucinous cystadenoma.3 borderline cystadenomas and 5 cystadenocacinomas were included in this study.Sixteen tumors(16/20)were located at pancreatic body or tail.The findings of thick walsl,calcifications and mural nodules appeared in 4,2 and2 cases respectively in benign mucinous cystic tumors,while appeared in 7,5,and 5 cases respectively in malignant mucinous cystic tumom.Presence of tIlick walls.calcifications and mural nodules in the lesions were significantly associated with malignancy(P＜0.05).Conclusion CT manifestations of pancreatic mucinous neoplasm are variable,but has some specific radiographic features.A combination of CT findings is helpful ifl differentiation of malignant and benign pancreatic mucinous adenomas.

Imaging appearance of primary hepatic neuroendocrine carcinomas / 中华放射学杂志

Objective To investigate the CT and MRI findings of primary hepatic neuroendocrine carcinomas.Methods Imaging findings of 6 patients with pathologically confirmed hepatic neuroendocrine carcinomas were retrospectively analyzed.Four patients underwent plain CT and contrast enhanced CT examinations.The other 2 patients underwent plain MRI and contrast enhanced MRI.Results One out of the 6 cases manifested multicentric tumor which appeared as one large tumor surrounded with multiple small nodules peripherally,and the tumors of the other 5 cases were solitary.On plain CT images,all lesions were well-defined and hypoattenuating with central areas of even lower density except punctuate calcifications at tumor periphery in 1 case.On pre-contrast MRI,the cases manifested heterogeneous low signal intensity on T1 wI and slightly high intensity on T2 WI.On dynamic contrast enhanced CT and MRI,Tumors manifested slight to mild enhancement in arterial phase,slight enhancement in portal venous phase or delayed phase with no enhancement in the center,accompanied by dislocation of surrounding vessels.There Was no lymphadenopathy in peritoneal cavity and retroperitoniurm. Conclusion CT and MRI scanning can demonstrate specific features of primary hepatic neuroendocrine carcinoma,which may help the diagnosis and differential diagnosis of the tumor.

The application and advantages of multi-slice CT in the diagnosis of myocardial bridging / 中华放射学杂志

Objective To investigate the ability of electrocardiogram-gated multislice CT(MSCT)in the diagnosis of myocardial bfidging.Methods Fifty-one patients(82 coronary arteries)with suspected coronary artery disease underwent multi-detector row CT,conventional coronary angiography and intravascular ultrasonography as well.The sensitivity,specificity and accuracy of MSCT for the detection of myocardial bridging were determined.The interobserver agreement was calculated by using Cohen's Kappa test.Results A total of 26 tunneled arteries exclusively located near the middle segment of left anterior descending coronary artery were found by coronary angiography and intravascular uhrasonography.Compared to the invasive methods,MSCT correctly detected 23 of 26 myocardial bridges with a sensitivity of 88%(23/26),specificity of 96%(52/54)and accuracy of 94%(75/80).The Kappa value for overall interobserver variation Was 0.62.Two myocardial bridges diagnosed by MSCT were missed with the invasive method.With the results of invasive and non-invasive methods combined as the standard of reference,the overall sensitivity.specificity,and accuracy of MSCT in detecting myocardial bridging were 89%(25/28),91%(21/23),and 90%(46/51),respectively.Conclusion As a non-invasive imaging modality,MSCT is feasible and reliable in the detection of myocardial bridging.

Comparative Study on 100 Cases of Chronic Hepatitis B Treated with Chinese Traditional and Western Drugs / 中医杂志

Fifty Cases of chronic B—hepatitis were treated withTCM based on differentiation of syndromes and com-pared with a control group of 50 cases treated withwestern remedies.Results showed that for the treatinggroup,the rate of negative return of HBeAg was64%,and the rate of positive return of HBe was 48%,while that of the control group were 20% and 10% re-spectively.