Bursa of Fabricius is a very important organ for B-eell development. We sot bursa extracts from 2-3 months old Peking Duck. A partially purified PFC-stimulating active factor has been seperated from the extracts by twice molecular sieve chromatography, Sephadex G-15 and Moselect G-10. The M. W. of the active factor is below 750 dal. The results of HPLC analysis of the factor show that its polarity is relatively strong, and it has more positive charges.The works of purifying and looking for a new assay are still going on.

Bursa of Fabricius is the central organ of B-cell development in birds. There are some active factors in Bursa that are involved in the maturation of B lymphocytes. Bursa extracts from 2-3 month-old peking Duck, with a M. W. of 10,000 dal, can obviously increase the number of plaque-forming cells (PFCs) in normal or cyclophosphamidetreated mouse spleen. Cyclophosphamide (CP) is a kind of B-cell inhibitor. The extracts can also increase the life expectation of mouse treated with deathal dose of CP. These results show that Bursa extracts contain a factor (or some factors) which can promote the development or function of B cells. The factor is named as Bursatin. Because the PFCs-stimulating activity of the factor is susceptible to high temperature and pronase E, Bursatin is infered to be a peptide. The effect of Bursa extracts on elevating the cAMP level of mouse spleen cells suggests that Bursatin may function via cAMP. Besides, it is interesting that we have found that the extracts can also increase the rumber of E-rosett forming cells in pig thymocytes. The result shows that there are several active factors or certain factor poesses different activities in Bursa extracts.

Objective To investigate the ultrasonographic characteristics of acute Stanford type A aortic dissection (ATAAD) involving the renal arteries and their relationship with renal function. Methods Patients with ATAAD admitted to Deyang People's Hospital from February 2013 to May 2023 were selected for the study. Based on whether the renal arteries were involved in the dissection, the patients were divided into two groups: a renal artery involvement group and a renal artery non-involvement group. General data and ultrasound characteristics of the two groups were compared. Logistic regression analysis and model correction were performed to analyze the relationship between ultrasound characteristics and renal function involvement in ATAAD patients. Receiver operating characteristic (ROC) curves were used to evaluate the predictive value of ultrasound characteristics for renal artery involvement in ATAAD patients. Additionally, patients in the renal artery involvement group were divided into normal renal function and abnormal renal function subgroups based on serum blood urea nitrogen (BUN) and serum creatinine (Scr) levels. Clinical data of the two subgroups were compared, and a log-binomial model was used to analyze the risk effects of ultrasound characteristics for abnormal renal function. Pearson correlation analysis was performed to assess the correlation between ultrasound characteristics of renal artery involvement and renal function indicators. Results A total of 163 patients were included, consisting of 106 males and 57 females, with a mean age of (50.06±10.46) years (ranging from 20 to 85 years). Significant differences in gender, Scr, and BUN were observed between the renal artery involvement group and the renal artery non-involvement group (P<0.001). Compared to the renal artery non-involvement group, the renal artery involvement group had an increased ascending aorta diameter, a greater proportion of ascending aortic dilation and poor renal perfusion (P<0.05). Logistic regression analysis indicated that ascending aorta diameter, ascending aortic dilation, and poor renal perfusion were independent factors for renal artery involvement (P<0.05). Ultrasonographic characteristics showed good predictive ability for renal artery involvement in ATAAD patients. Furthermore, the combination of the three characteristics yielded a higher predictive value for renal artery involvement. Compared to the normal renal function group, the abnormal renal function group had higher BUN and Scr levels, increased ascending aortic diameter, a greater proportion of ascending aortic dilation and poor renal perfusion (P<0.05). The log-binomial model analysis revealed that the risk ratios for ascending aortic diameter, ascending aortic dilation, and poor renal perfusion were statistically significant both before and after adjustment (P<0.05). Pearson correlation analysis revealed that ascending aortic diameter, ascending aortic dilation, and poor renal perfusion were strongly correlated with renal function parameters (P<0.05). Conclusion Ultrasound characteristics of ATAAD involving the renal arteries are associated with renal function. Ascending aorta diameter, ascending aortic dilation, and poor renal perfusion are independent risk factors for abnormal renal function.