AIM: To explore a simple, reliable method for tissue processing and section staining by extracting DNA from the manually microdissectioned specimen, and to identify whether the extracted DNA is useful in the following study at molecule level. METHODS: The experiment was performed at the pathological laboratory of Guangdong Medical College from July 2004 to July 2007. The paraffin imbedding tissue sections of cervical cancer were thoroughly deparaffinized after mounted on slides for a long period of time. The nucleus was slightly stained with hematoxylin and microdissectioned under inverted microscope. The microdissectioned samples were put into EP tubes filled with digestion buffer to split the cells and then the DNA was extracted. During the whole course, PE tubes did not change, and the complicated phenol/chloroform extraction did not perform. The DNA extraction was rapid and simple. RESULTS: The DNA was measured by the spectrophotometer with concentrations from 0.14 to 5.25 g/L and absorbance values of A260/A280 were 1.6-1.8. All samples were amplified with PCR to produce expected length specific target fragment (231 bp). CONCLUSION: Rapid DNA extraction after manual tissue microdissection can produce adequate amount of DNA and maintain good quality of DNA template for PCR. The DNA meets the need of the following molecular experiments.

Objective To summarize the experience in transanal local excision (LE) for rectal cancer (RC). Methods The clinical data of 28 cases of RC treated by LE from 1988 to 1998 were analyzed retrospectively. Results In this series, five-year survival rate was 83.4?6.2%, and the local recurrence rate (LRR) was 17.8%. In well-differentiated carcinoma, 4 cases were convinced as local recurrence with a LRR of 17.4%(4/23); in moderately- differentiated carcinoma, one case with a LRR of 20.0%(1/5). The LRR in T 1 and T 2 group was 15.0% (3/20) and 25.0% (2/8) respectively. LRR was 16.7% (4/24) in patients with less than 1/3 bowel wall involved, LRR was 16.7%(4/24),whereas LRR was 25.0%(1/4) in more than 1/3 bowel wall involved group. In total bowel wall resection group the LRR was 16.7%(3/18) while in partial resection group was 20.0% (2/10). In patients with tumour size larger than 4 cm LRR was 22.2% (2/9), tumour size smaller than 4 cm LRR was 15.7% (3/19). Conclusion LE for RC might only be successfully performed in selected patients (T 1～T 2, N 0M 0, well or moderately-differentiated carcinoma,low RC within 6 cm from anal edge). The indications of transanal LE must be controlled strictly. Total excision of tumor and prevention of implantation of carcinoma are the main points in the prophylaxes of recurrence. Postoperative follow-up is needed in order to find local recurrence as early as possible.

Objective To propose a method for abdominal multi-organ segmentation assisted by multi-phase CT synthesis.Methods Multi-phase CT synthesis for synthesizing high-quality CT images was used to increase the information details for image segmentation.A transformer block was introduced to help to capture long-range semantic information in cooperation with perceptual loss to minimize the differences between the real image and synthesized image.Results The model was trained using multi-phase CT dataset of 526 total cases from Nanfang Hospital.The mean maximum absolute error(MAE)of the synthesized non-contrast CT,venous phase contrast-enhanced CT(CECT),and delay phase CECT images from arterial phase CECT was 19.192±3.381,20.140±2.676 and 22.538±2.874,respectively,which were better than those of images synthesized using other methods.Validation of the multi-phase CT synthesis-assisted abdominal multi-organ segmentation method showed an average dice coefficient of 0.847 for the internal validation set and 0.823 for the external validation set.Conclusion The propose method is capable of synthesizing high-quality multi-phase CT images to effectively reduce the errors in registration between different phase CT images and improve the performance for segmentation of 13 abdominal organs.

Objective To propose a method for abdominal multi-organ segmentation assisted by multi-phase CT synthesis.Methods Multi-phase CT synthesis for synthesizing high-quality CT images was used to increase the information details for image segmentation.A transformer block was introduced to help to capture long-range semantic information in cooperation with perceptual loss to minimize the differences between the real image and synthesized image.Results The model was trained using multi-phase CT dataset of 526 total cases from Nanfang Hospital.The mean maximum absolute error(MAE)of the synthesized non-contrast CT,venous phase contrast-enhanced CT(CECT),and delay phase CECT images from arterial phase CECT was 19.192±3.381,20.140±2.676 and 22.538±2.874,respectively,which were better than those of images synthesized using other methods.Validation of the multi-phase CT synthesis-assisted abdominal multi-organ segmentation method showed an average dice coefficient of 0.847 for the internal validation set and 0.823 for the external validation set.Conclusion The propose method is capable of synthesizing high-quality multi-phase CT images to effectively reduce the errors in registration between different phase CT images and improve the performance for segmentation of 13 abdominal organs.