Biomechanical Test on Novel Arc Cervical Titanium Mesh with Endplate Ring / 医用生物力学

Objective To establish the instability model of goat cervical vertebrae, and test biomechanical stability of the novel arc cervical titanium mesh with endplate ring. Methods The anatomical data from cervical vertebrae of adult goats were measured, so as to select a new type of arch cervical titanium mesh with endplate ring which was suitable for goat cervical vertebrae. A total of 24 goats with preserved articular capsule, ligaments and intervertebral disc were randomly divided into 4 groups. Group A (n=6, normal group) didn’t receive any special treatment, while Group B (n=6, model group) received partial resection of C4 vertebrae as well as upper and lower intervertebral disc. On the basis of models in Group B, Group C (n=6, experimental group) was installed with the novel arch cervical titanium mesh and fixed by plate and screw, and Group D (n=6,control group) was installed with traditional straight titanium mesh and fixed by plate and screw. The ranges of motion (ROMs) for 4 groups of specimens during flexion, extension, left/right lateral bending, left/right rotation under 2.0 N·m load were measured, and their three-dimensional (3D) motion stability was tested. The displacement of Group C and Group D under 200 N compression force was measured, the stiffness was calculated, and the anti settlement ability of the whole specimen was tested. Results The ROMs of Group A in all directions were smaller than those of Group B,the ROMs of Group A were larger than those of Group C, and the ROMs of Group C during flexion were smaller than those of Group D (P<0.05). The stiffness of Group C was higher than that of Group D (P<0.05).The compression displacement of Group C was smaller than that of Group D(P<0.05). Conclusions Compared with the straight titanium mesh, the novel arc titanium mesh is more consistent with the physiological curvature of cervical verebrae, and has better stability than the traditional titanium mesh during the most frequent flexion activities of cervical verebrae. Moreover, compression displacement of the novel arc titanium mesh under short-term stress is smaller than that of the straight titanium mesh, and its postoperative anti-settlement is better than that of the straight titanium mesh, which is worthy of further experiment and clinical promotion.

Development of a peer evaluation form and a self-evaluation form to acquire oral presentation skills / 医学教育

1) We have developed two forms to evaluate students' oral presentation skills (important but hard to teach in the medical school curriculum): one is a peer review form for an audience to evaluate a presenter's performance, and the other is a form for a presenter to evaluate his or her own performance.2) The evaluation process is simple: evaluators fill out the forms by checking the items for evaluation. With these evaluation forms students can get tips for improving their presentations because technical suggestions are written near each item.3) The forms were beneficial for both students and instructors, because students could get tips for improving their presentations, and instructors could concentrate their efforts on scientific content after the students' presentations.

Cloning Expression and Characterization of Two Cysteine Proteinases of Clonorchis sinensis / 热带医学杂志

Objective To clone and express the valuable Clonorchis sinensis antigen molecules which can be applied to the diagnosis of clonorchiasis. Methods Based on the sequences (Genbank) No. AF271091 (CysA) and No.AF093242 (CysB), primers were designed to amplify the two C. sinensis cysteine proteinase genes and expressed in E.cloi. The expressed proteins were purified by affinity chromatography and then tested for their immunological characters.Results The two genes were successfully cloned and expressed. Western blot showed that CysB had strong reaction with clonorchiasis sera and very weak reaction with schistosomiasis sera, while CysA showed no reactivity with the probed sera. Immunohistochemistry showed that both proteins were mainly located in adult worm intestines and the intrauterine eggs.Conclusions The results suggested that, of the two expressed C. sinensis proteins, CysB had good antigenic reactivity against sera from patients. It is a potential candidate of diagnostic antigens for clonorchiasis.

FURTHER EVIDENCE THAT GENOTYPE I AND GENOTYPE II OF CRYPTOSPORIDIUM PARVUM ARE DISTINCT

Three new genes of <I>Cryptosporidium parvum</I> were cloned, including a gene encoding methionine aminopeptidase, one encoding chaperonin containing T-complex protein 1 delta (TCP-1 delta) and one with unknown function. DNA sequence analysis indicated that these genes are quite conserved, but there were some base pair differences between genotype I and genotype II isolates. These differences were confirmed by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the 3 genes from 41 isolates collected from different hosts and geographical origins. In brief, the band patterns generated by endonuclease Hind III or Hinf I restrictions of the gene of methionine aminopeptidase, Sac I restriction of the gene of chaperonin, or Ava II restriction of the unknown gene could differentiate the isolates of <I>C. parvum</I> into genotype I and genotype II. PCR primers based on these genes amplified only <I>C. parvum</I> genes. Even a single oocyst was detectable with these PCR primers. Thus the results provided further evidence that genotype I and genotype II are distinct, and our three new primers can be used to detect and characterize <I>C. parvum</I> isolates with high sensitivity.