Argonaute protein as a linker to command center of physiological processes

MicroRNAs （miRNAs） post-transcriptionally regulate gene expression by binding to target mRNAs with perfect or imperfect complementarity, recruiting an Argonaute （AGO） protein complex that usually results in degradation or translational repression of the target mRNA. AGO proteins function as the Slicer enzyme in miRNA and small interfering RNA （siRNA） pathways involved in human physiological and pathophysiological processes, such as antiviral responses and disease formation. Although the past decade has witnessed rapid advancement in studies of AGO protein functions, to further elucidate the molecular mechanism of AGO proteins in cellular function and biochemical process is really a challenging area for researchers. In order to understand the molecular causes underlying the pathological processes, we mainly focus on five fundamental problems of AGO proteins, including evolution, functional domain, subcellular location, post-translational modification and protein-protein interactions. Our discussion highlight their roles in early diagnosis, disease prevention, drug target identification, drug response, etc.

Experimental study of changes of TNF-α in rabbits with steroid-induced avascular necrosis of femoral head

Objective: To explore the effect of tumor necrosis factor-α(TNF-α)on the occurrence of steroid-induced avascular necrosis of femoral head(SANFH). Methods: Twenty-four rabbits were firstly divided into void group (n=12) and model group (n=12) at random. Prednisone Acetate was injected to the model group(0.32 mg·kg^(-1)·d^(-1)). In the 6 th and 8 th week, two rabbits of the two groups were killed respectively to observe whether the model was successful. The level of TNF-α in serum of the residual rabbits of the two groups was examined in Radioimmunoassay method. Results: The level of TNF-α in model group is significantly higher than that in void group(P<0.001) under the premise of the model of SANFH success by histological observation. Conclusion: The rise of level of TNF-α may be one of the most important factors in the occurrence of SANFH.

SAFETY MARGIN IN ANUS-SAVING RESECTION FOR LOW RECTAL CANCER

The length and method of measurement of the safety-margin below the rectal cancer, being of the utmost importance for its prognosis, is still under debate.The following study was designed and done for its solution.Light microscopic examination was done on 83 resected rectal cancer specimens to assess the extent of intramural invasion towards the anus.By use of a ruler,the distance between the lower tumour margin and the resection line or the dentate line was measured when the specimen was:l. freshly resected,2.after fixing in 10% formalin, and 3.after being mounted in sections. The measurements were compared. By the same method,the distance between the lower tumor margin and the intended resectyion line was measured immediately before resection.It was compared with the measurement immediately after the resection.In 83 rectal cancer specimens, the extent of intramural infiltration toward the anus was:≤0.5 cm in 75 cases (90.4%).≥l cm in 2 cases which showed highly malignant carcinomas.These 2 cases, however,should not have been indicated for anus-saving resection.In 46 fresh specimens,the tumor-resection line distances gave an average of 2.7 cm.After fixing in 10% formalin, they became shortened by 0.7 cm. And, mouting in sections further shortened them by another 0.5 cm,giving a total shortening of l.2 cm.The tumor-resection line distance in 7 of the 11 fresh specimens resected by the Dixon's operation was shortened,though never more than o.5 cm immediately the operation.In performin ganus-saving resection for the low rectal cancer, after full isolation the rectum and stretching it slightly,≥3 cm of the rectum distal to the lower tumor margin should be resected.A safety margin of more than 2.5 cm is necessary in the fresh specimen.If formalin fixed specimen is measured, the safety margin should be ≥2 cm.