BACKGROUND:The combination of fiber post and resin core for restorations of mesial or distal defects of the maxil ary central incisor can restore the elastic modulus close to the nature dentin, and achieve good aesthetic effects. However, when a complete dentin col ar cannot be prepared due to a large number of dental tissue defects, the post and core are easy to be lost or fractured after defect repair using the combination of fiber post and resin core.
OBJECTIVE:To compare the stress distribution after nickel-chromium cast post and core, gold-pal adium cast post and core, and fiber post and resin core were used for restorations of mesial or distal defects of the maxil ary central incisors using three-dimensional finite element analysis.
METHODS:An intact adult maxil ary central incisor that meets the average dental anatomical value in China was selected and scanned using a dental cone-beam CT. Then, three-dimensional tooth-fiber post and core (nickel-chromium cast post and core or gold-pal adium cast post and core)-al-ceramic crown models of mesial or distal defects of the maxil ary central incisors and part loss of dentin col ar were established using ABAQUS analysis. After repair with nickel-chromium cast post and core, gold-pal adium cast post and core, and fiber post and resin core, stress distribution in the loaded state was compared using the ABAQUS three-dimensional finite element analysis.
RESULTS AND CONCLUSION:The stress peak at the adhesive and cast layers in the fiber post and resin core group was significantly lower than that in the nickel-chromium cast post and core or gold-pal adium cast post and core group. It indicated that the tooth root was easy to be fractured after mesial or distal defects of the maxil ary central incisors with partial loss of dentin col ar were restored with nickel-chromium cast post and core, gold-pal adium cast post and core. In addition, the stress peaks at the dentin layer were consistent for fiber post and core, nickel-chromium cast post and core, and gold-pal adium cast post and core. These findings indicate that the combination of fiber post and resin core is better for restorations of mesial or distal defects of the maxil ary central incisors.

ObjectiveImpairment in auditory comprehension is one of the most common clinical symptoms of aphasia. Analysing the features of Chinese aphasics in auditory comprehension might be valueable to classify the types of aphasia, distinguish the difference between the Western aphasics and Chinese aphasics, and find out the neural mechanisms in the language processes in the brain. MethodsThe Standardized Aphasia Battery in Chinese and Additional Test of Auditory Comprehension were utilized, and the cerebral lesion of each case was demonstrated by CT scan or MRI. Results and Conclusions 1.Different types of aphasia indicate different damage grades in auditory comprehension impairment at each stage. 2. Posterior apasia and mixed aphasia indicate damages in the phonemic discrimination abilities. There are phonemic discrimination abilities preserved in Anterior aphasia and subcortical aphasia. 3. Anterior aphasia, posterior aphasia and mixed aphasia are at a different difficulty grades for lexical comprehension, especially for the discrimination to body parts. Subcortical aphasia doesn\'t demonstrate this feature that might be the characteristic in Chinese aphasics different from English aphasics. 4. The comprehension of the passive sentences is more difficult than that of the active sentences for all types of aphasics . 5. The damages are all severe in the story comprehension for all types of aphasics.

Recent studies about stem cells show that the formation of portal vein tumor thrombus(PVTT)is closely relative to the metastasis of liver cancer stem cells induced by portal vein microenvironment.Liver cancer stem cells first detach from the primary tumor,extravasate to extracellular matrix,stimulate angiogenesis or intravasate and migrate through the systemic circulation,evade host defense mechanisms,migrate to specific blood vessel sites through chemo-taxis and attach to blood vessel wall,then extravasate through blood vessel and home to specific microenvironment and to form PVTT.

OBJECTIVE: Cerebral vasospasm (CVS) induced by subarachnoid hemorrhage (SAH) is a difficulty in neurosciences. Because the pathogenesis of CVS remains a matter of discussion, clinical prevention and treatment are currently not sufficient. With the application of advanced experimental technology in recent years, great breakthroughs have been achieved in domestic and foreign studies on potassium channels. Definite mechanism in the region plays a significant role in instruction for clinical prevention and treatment. In this paper, researches related to potassium channels in cerebral vascular vessels after SAH are reviewed.DATA SOURCES: Related articles published between January 1991 and December 2005 were searched by the computer in Medline database with the key words of "potassium channels, subarachnoid hemorrhage, cerebral vasospasm" and the language was limited to English. Meanwhile, relevant articles were also searched in CNKI and Wanfang database with the same key words in Ghinese.STUDY SELECTION: All articles were selected firstly, and literatures related to potassium channel on physiology and pathogenesis of SAH-induced CVS were selected. Researches on biochemistry and gene etc were excluded.DATA EXTRACTION: A total of 45 English articles were collected, among which, 17 met the inclusion criteria. Of 2 Chinese articles collected,one study was in accordance with the inclusion criteria. Eighteen literatures on the pathological and physiological mechanism of CVS after SAH were looked for the full text.DATA SYNTHESIS: Researches showed that remarkable changes occurred in potassium channels in CVS after SAH, while potassium channel modulators had significant interventional effect on CVS in animal experiment by promoting or blocking the ion movements.CONCLUSION: Potassium channels plays an important role in the pathogenesis of SAH-indueed CVS. Some therapeutic intervention may be provided based on the studies of potassium channels in CVS.

Constipation ; diagnosis ; therapy ; Humans ; Medicine, Chinese Traditional ; Rectum ; physiopathology ; Syndrome ; Touch

Objective To observe the biological characteristics and analyse primary therapeutic response of acute erythroid leukemia.Methods The data of 28 patients primarily diagnosed as acute erythroid leukemia were analyzed.The patients were divided into with muhilineage dysplasia group and without muhilineage dysplasia group,and the morphology,immunology,cytogenetics and molecular biology characteristics and the complete remission rate of the first induction therapy were compared.Results There were 14 cases(50％)with muhilineage dysplasia,which involved in two lineage or trilineage.In 6 cases by flow cytometry,the myeloid blast immunophenotypes were common expressed.In 8 cases detected by karyotype analysis,5 cases were chromosomal abnormal,including 4 cases were complex chromosomal abnormal,1 case was trisomy 8.In 4 cases underwent WT1 detection,all of them were positive.The complete remission rate of the first induction therapy was 39.29％(11/28),the ratein the multilineage dysplasia group was 35.71％(5/14),and the ratein without multilineage dysplasia group was 42.86％(6/14),the difference had no statistical significance(P＞0.05).The complete remission rate of the complex chromosome group was 25.00％(1/4),the intermediate prognostic group was 50.00％(2/4).Conclusions Acute erythroid leukemia had special biological features different from other subtype AML:accompanyed with high frequency of multilineage dysplasia.The abnormality of karyotype were high,and it was often complex karyotype involved with chromosome 5 and/or chromosome 7,which had a low complete remission rate.The complete remission rate of chemotherapy was low,treatment effect was poor.

Objective To investigate the possible way through which transplanted Sertoli cells support the nerve tissues in vivo.Methods Culture the isolated cells from the fetal mouse cerebral cortex alone(coated the culture plate with poly-D-lysine previously),the control group,or with prepubertal homologous Sertoli cells(planted Sertoli cells beforehand),the coculture group.To observe the morphological changes of the cultured neurons,neural stem cells(NSC) and neuroglial cells every day and compared the differences in their growth between the tow groups.Sertoli cells,neurons and NSC were identified by the expression of Fas ligand,neuron-specific enolase(NSE) and Nestin in the cytoplasm respectively.Results A significant increase of both the survival of neurons(P

In order to probe into effect of stimulation of wind, cold and Sdampness to the cervical part on oxygen free radical and prostaglandins, 24 rabbits were randomly assigned to control group and wind - cold - Sdampness group, head - lowering group and combined model group, 6 rabbits in each group, and changes of superoxide dismutase (SOD),lipid hyperoxide (LPO), prostanglandin E2 (PGE2), 6 -keto -PGF1a in affected local region and blood were observed. Results indicated that the commonly - seen pathogenetic factors of cervical spondylopathy such as wind, cold , dampness and lowering head might cause aspetic inflammation of the cervical part and abnormality of SOD, LPO, PGE2 and 6 - keto - PGF1a in affected local tissue and blood, and abnormal metabolism of oxygen free radical and prostagnadins might be one of important mechanisms of cervical spondylopathy induced by wind, cold and dampness.