Finite element analysis is a matrix method for structure analysis. It divides a continuum composed of infinite material points and finite degree of freedom into an aggregation with finite small units. Finite element analysis is used to analyze the biomechanical properties of cervical vertebra under pathologic and physiologic conditions and the influence of different surgeries and fixation device on cervical biomechanics. In addition,the application of finite element analysis in cervical biomechanics study is prospected. Due to differences between finite element model and actual human body,calculation results are always limited and fixed. With development of computer and software,finite element analysis will become a focus of spinal mechanics.

Objective To describe the clinicopathologic features of two cases of mucoepidermoid carcinoma of the skin.Methods Two cases of mucoepidermoid carcinoma of the skin were analyzed histopathologically using hematoxylin and eosin (HE) staining,alcian blue-periodic acid Schiff (AB-PAS) staining and immunohistochemical staining.Relavant literature was reviewed.Results Histopathological examination showed that the tumor was subcutaneously located in both cases,with epidermoid cells and intermediate cells arranged in sheets or nests,as well as different sizes of glandular structures lined by mucinous columnar epithelium in some areas.Both tumors had a relatively clear boundary with peripheral invasive growth and no obvious capsules.Immunohistochemical examination showed positive staining for carcinoembryonic antigen (CEA),high and low molecular weight cytokeratin (CK(H) and CK(L)).The cytoplasm of mucous cells was stained blue with,and mucus was visualized after,AB-PAS staining.Conclusions Primary mucoepidermoid carcinoma of the skin is a kind of malignant tumor arising from skin appendages,whose diagnosis depends on histological and immunohistochemical examination.

Objective To develop an immunohistochemical assay for the diagnosis of cutaneous malignant melanoma (CMM) micrometastasis via blood and lymphatic vessels,and to evaluate its clinical significance.Methods Fifty-three patients (32 males and 21 females) histopathologically diagnosed as CMM were enrolled in this study.The patients were aged (61.2 ± 8.4) years (range,52-72 years).Tissue specimens were obtained from the central area of tumor in each case,and also from removed lymph nodes in some cases.The average duration of follow-up was (65.00 ± 5.68) months.During the follow-up,17 patients died of the recurrence or metastasis of CMM,and 6 patients were lost to follow-up.The expressions of D2-40,S100 and CD34 antigens in 53 tissue specimens were examined by immunohistochemical staining with three individual monoclonal antibodies,or by an immunohistochemical method using 2 two-antibody cocktails (D2-40/S 100 and CD34/S100) and double-color chromogens in single tissue sections.Results Of the 53 patients,30.19％ (16/53) were positive for hematoxylin-eosin (HE) staining combined with immunohistochemical staining with individual monoclonal antibodies,and 49.06％ (26/53) for the immunohistochemical method using two-antibody cocktails and double-color chromogens.Statistical differences were found in the positive rate between the two methods (x2 =3.94,P＜ 0.05).Compared with patients without blood/lymph vessel tumor emboli,those with blood/lymph vessel tumor emboli showed higher lymph node metastasis rate (80.77％ (21/26) vs.37.04％ (10/27),x2 =10.43,P ＜ 0.001),but lower five-year survival rate (42.31％ (11/26) vs.70.37％ (19/27),x2 =4.25,P ＜ 0.05).Conclusions The immunohistochemical method with two-antibody cocktails is superior to HE staining combined with immunohistochemical staining with individual monoclonal antibodies in the detection of blood/lymph vessel tumor emboli.And blood/lymph vessel tumor emboli may be an important prognostic factor in patients with CMM.

A 69-year-old male patient presented with a gradually enlarging mass in the left inner upper thigh for more than 2 months,and pigmented patches in the left medial leg for more than 20 years.Physical examination revealed a painless mass measuring 3 cm × 2 cm × 2 cm in size in the left inner upper thigh.Several pigmented patches were observed in the left medial leg,and the largest pigmented patch measured 2 cm× 2 cm in size with an irregular border and uneven pigmentation.The mass in the left inner upper thigh was resected and subjected to histopathological examination,which showed proliferative epithelioid neoplastic cells with mucous matrix,round and spindle cells of varying sizes separated by mucous matrix.The immunohistochemical study of tumor cells showed positive staining for vimentin,S100 and Melan-A,but negative staining for actin,desmin,CD56,epithelial membrane antigen,cytokeratin,leukocyte common antigen,CD99,chromogranin A and synaptophysin.Hematoxylin-eosin staining of pigmented patches on the left medial leg revealed squamous epithelium covering the surface of lesions with no superficial ulceration or atypia in epithelial cells,unevenly distributed melanophages,fibroplasia accompanied by collagen formation,obviously decreased skin appendages,infiltration of a few inflammatory cells in the dermis.AB-PAS staining was negative.The immunohistochemical study of pigmented patches showed positive staining for vimentin and Melan-A.The patient was pathologically diagnosed with metastatic myxoid melanoma with partial regression of the primary lesion.

Objective To investigate the changes in pulmonary gas exchange and intrapulmonary shunting during orthotopic liver transplantation (OLT) without veno-venous bypass. Methods Sixteen ASA III-IV patients with end-stage liver diseases were studied. Anesthesia was induced with midazolam 0.1 mg ? kg-1 , fentanyl 10 ?g kg -1 , scopolamine 0.6 mg, and vecuronium 0.1 mg ? kg-1 and maintained with isoflurane and propofol infusion (2-3 mg? kg-1h-1 ) supplemented with intermittent iv boluses of midazolam, fentanyl and vecuronium. The patients were intubated and mechanically ventilated with 100% O2 Swan-Ganz catheter was inserted via right internal jugular vein. Radial artery was cannulated. MAP, HR, ECG, CVP, SpO2 and PET CO2 were continuously monitored. Body temperature was maintained at≥35.5℃ during operation. Blood samples were taken from radial and pulmonary artery for blood gas analysis. P(A-a) O2 and Qs/Qt were calculated immediately before operation (T1 ), cross-clamping (T2) and unclamping of inferior vena cava and portal vein (T3 ) , 5 min (T4) and 90 min (T5 ) after graft reperfusion and at the end of operation (T6). Results P(A-a) O2 and Qs/Qt were both higher than normal value at T1 . PaCO2, P(A-a) O2 and Qs/Qt increased significantly at T3 and T4 as compared with those at T2 P(A-a)O2 and Qs/Qt were significantly decreased at T5 and T6 as compared with those at T3 and T4 Qs/Qt was positively correlated with P(a-A) O2 and PAP. Conclusion There is a certain degree of intrapulmonary shunt before and during orthotopic liver transplantation without veno-venous bypass. The amount of fluid infused should be strictly controlled during anhepatic phase.

The neonatal period is important for the dramatic increment as well as function improvement of islet β-cell.β-cell mass augmentation is primarily regulated by neogenesis,replication,and apoptosis.The mechanisms involve cell cycle related proteins and mitosis-promoting signaling pathways.This remodeling period has far-reaching effects on the body in adapting to the metabolic needs and regulating glucose homeostasis later in life.

Objective To evaluate the effect of probucol on endothelium-dependent vasodilatation(i,e.flow- mediated dilation,FMD) function of the old patients with isolated systolic hypertension.Methods In this single- blind study,a total of 64 old pariems with isolated systolic hypertension were randomized to receive conventional an- tihypertensive therapy and probucol (0.5g twice daily,group A,n=33) or receive conventional antihyperrensive therapy(group B,n=31) for 12 weeks.The levels of blood lipid were measured and vascular endothelial function was assessed in the brachial artery by high-resolution ultrasound technique in form of endothelium-dependent vasodi- latation before and after treatment.Results After 12-week treatment,the levels of TC,LDL-C and HDL-C in group A were significantly reduced compared with those before treatment(all P0.05).Flow-mediated dilatation parameters in both groups were obviously improved compared with those before treatment( P

Mitochondria play important roles in cellular energy metabolism,free radical generation and apoptosis. Mitochondrial dysfunction is one of the most profound features of cancer cells. Several distinct differences between the mitochondria of normal cells and cancer cells have been observed at the molecular,biochemical,metabolic and genetic levels. In this article,we review the relationship between mitochondrial DNA (mtDNA) and carcinogenesis of cancer cells. The possible mechanisms are also discussed.

Objective] To observe the diagnosis value of noninvasive diagnosis model S index used to evaluate the fibrosis degree of slight chronic hepatitis B(CHB). [Method] Trace back and investigate the routine serological indicators GGT, PLT, ALB and liver aspiration biopsy results of 63 cases of CHB;use noninvasive diagnosis formula to calculate:S index=1000×GGT/(PLT×ALB2),use ROC curve to analyze and evaluate the clinical diagnosis value of S index. [Result] S index is in positive relation with liver fibrosis degree. S index can forecast the fibrosis having or not with best truncation point 0.04h, the sensitivity 87.0%, specificity 47.5%and area under the curve(AUC) 0.690,close to 0. 7; in forecasting obvious fibrosis, with best truncation point 0.04h, sensitivity 100%,specificity 36.8%,AUC 0.664. [Conclusion] S index used for forecasting slight CHB having or not fibrosis has high value of diagnosis, but it has low correctness for diagnosing having or not obvious liver fibrosis.

Implantable Neurostimulators ; Micro-Electrical-Mechanical Systems ; Microelectrodes