In order to understand deeply the present situation and countermeasures of skipping classes among undergraduates,this paper uses questionnaire investigation,mathematical statistics and logical analysis to study the medicos and non-medicos in Guangzhou.The result shows it is very important to pay more attention to education,improve the quality of teaching,and so on.

AIM: To investigate relationship between activity of matrix metalloproteinases-2 ( MMP-2, 72 kD) and invasion, metastasis of breast cancer. METHODS: Useing zymography and computer software assisted analysis, the activitive levels of MMP-2 (72 kD) in tissues from breast cancer were measeured. RESULTS: Mean activitive levels of MMP-2 72 kD (13.93?3.60) in breast cancer were lower than those in benign disease (21.43?8.31), P0.05) in MMP-2 62 kD+72 kD of benign and malignant disease, but MMP-2 62 kD (13.83?4.53) and MMP-2 62 kD/62 kD+72 kD(0.48) respectively were significantly higher in malignant disease (P

AIM: To investigate relationship between activity of matrix metalloproteinases - 2 ( MMP - 2, 72 kD) and invasion, metastasis of breast cancer. METHODS: Useing zymography and computer software assisted analysis, the activitive levels of MMP- 2 (72 kD) in tissues from breast cancer were measeured. RESULTS: Mean activitive levels of MMP- 272 kD (13.93 + 3.60) in breast cancer were lower than those in benign disease (21.43 + 8.31), P < 0.05. There was no difference (P > 0.05) in MMP - 2 62 kD + 72 kD of benign and malignant dis ease, but MMP - 262 kD ( 13.83 + 4.53) and MMP - 262 kD/62 kD + 72 kD (0.48) respectively were significantly higher in malignant disease (P < 0.01). It was also found that MMP- 262 kD/62 kD + 72 kD were apparently higher in invasive carcinomas (0.48) and lymph node metastases (0.61), P < 0.01, respectively. CONCLUSION: These results demonstrated that a clear relationship between MMP - 2 activity and the invasion and metastasis of breast carcinoma.

Objective To investigate clinical effects of g rafting of vascular sural nerve.Methods From1998to 2003,97cases of the defects o f the distal ulnar artery and nerve we re repaired by grafting of sural nerv e with anastomosis of short saphenous vein.Results All the cases were followed up for 6to24months.They were e-valuated according to the modified S eddon rating system.The total excellent and good rate was 80.41%.The ex-cellent and good rate of the emergency cases was 89.74%,while the excelle nt and good rate of second operation was74.14%.Conclusions Grafting of sural nerve with anastom osis of short saphenous vein is an effective method to repair the defects of distal ulnar artery and nerve of the forearm,because the procedure is easy,the nerve and vein are widely available,and the nerve is th ick enough to be foldable.The artery can be repaired after reverse vascul ar anastomosis so as to improve the bloo d circulation of limbs and prevent nerve necrosis.[

Objective To study the significance and value of imaging typing by analyzing the correlation between contrast-enhanced ultrasound perfusion imaging typing and vascularization in patients with primary hepatocellular cancer.Methods The early enhanced arterial phase reflecting angioarchitecture,and the size and edge of enhanced tumor closely related to microvessel distribution, position and density, were observed and analyzed in 89 patients (113 lesions).All the cases were pathologically proved, and some received immunohistochemisty staining and the microvessel density were recorded.Results The perfusion imagings were classified into 4 types according to changes on contrast-enhanced ultrasound,dendritic,mixed,circular and net-like type.Atypia vessels were commonly seen in dendritic type,and Ⅲ and Ⅳ accounted for 79.1%.The microvessel density was higher than the other types.The circular type was relatively regular and Ⅲ and Ⅳ accounted for 12.5%.The microvessel density was lower than the other types.Combined with the contrast-enhanced ultrasound perfusion imaging and compared with pathological grading,growing methods and microvessel density, the dendritic type was characterized by infiltrative growth, and had strong invasion tendency.The circular type was characterized by expansive growth.And the other two types were characterized by transitional type.Conclusions Contrast-enhanced ultrasound can reflect the angioarchiteeture, the microvessel density and the position,and it is related to the pathological grading and growing methods.

Objective    To explore the potential role of tumor spread through air spaces (STAS) as a prognostic indicator of non-small cell lung cancer (NSCLC) through meta-analysis. Methods    PubMed, EMbase and Web of Science, from inception to February 2022 were searched by computer about the research of the 5-year overall survival (OS) and recurrence free survival (RFS) of NSCLC patients with or without STAS. The Newcastle-Ottawa scale (NOS) was used to evaluate the quality of each study. Results    Totally 13 published articles were included with 4 647 patients, and 1 424 (30.6%) patients had STAS. The NOS score of all studies≥6 points. The meta-analysis showed that compared with the NSCLC patients without STAS, those with STAS had a worse prognosis of 5-year RFS, and the combined HR was 1.89 (95%CI 1.61-2.23); they had a shorter 5-year OS, and the combined HR was 2.25 (95%CI 1.79-2.84). There was no statistical heterogeneity among studies. Conclusion    The presence of STAS may be a poor prognostic factor for patients with NSCLC, and enough attention should be paid. The STAS should be recorded in the pathological report to guide the comprehensive treatment and evaluate the prognosis of patients.