Coding joint diversity in mature and immature B-cell lines.

Antigen receptor gene rearrangement is regulated by many factors in B and T lymphocytes. The sequences of the gene segments themselves, their associated recombination signal sequences (RSS), expression of the RAG genes and the chromatin accessibility of the particular gene segments to be rearranged all influence the outcome of recombination and thus antigen receptor diversity. In the present study, we have evaluated the effect of variations in RAG activity level on the junctional diversity of coding joint sequences. Using the pre-B-like 204-1-8 and the mature B DR3 cell lines under different transfection conditions, we were able to investigate recombination activity levels that varied 100-fold. We evaluated the sequences of the coding joints for junctional diversity resulting from nucleotide addition or deletion. Surprisingly, we found that the sequence of coding joints of these recombinants did not exhibit significant variation despite the large difference in recombination frequency. Our results indicate that the fidelity of the joining phase of V(D)J recombination is not jeopardized by varying RAG activity.

Comparative study of five preoperative methods for the localization of accessory pathways in the Wolff-Parkinson-White syndrome.

One hundred and thirty-four cases of Wolff-Parkinson-White syndrome were studied to evaluate the relative usefulness of electrocardiography (ECG), electrophysiological studies (EPS), body surface mapping (BSM), gated blood-pool phase analysis (nuclear studies), and vectorcardiography (VCG) in the localization of the accessory pathway (ACP). In comparison with the final localization verified by intraoperative studies, 93.4% in 8-region ACP localization (97.7% in 4-region ACP localization) could be correctly localized by ECG using our criteria, 83.9% (86.8%) by EPS, 82.6% (95.8%) by BSM, 78.8% (87.7%) by nuclear studies, and 67.3% (78.0%) by VCG. It was concluded that: (a) ACP can be localized preoperatively with considerable accuracy by using our simple ECG criteria. (b) The EPS method has some limitation, especially with respect to 8-region ACP localization. (c) Our observation showed no evidence that BSM, VCG, or nuclear studies were superior to ECG in ACP localization. (d) Among the 5 methods studied, ECG and EPS appear to be the appropriate procedures for preoperative ACP identification.

[Clinical and experimental study of treating aplastic anemia with fetal liver cell suspension and fetal liver cell-free suspension].

Fresh fetal liver obtained from 3- to 6-month fetus was prepared. Fetal liver cell suspension (FLC) or fetal liver cell-free suspension (FLCF) were then transfused into two groups of patient of aplastic anemia. 15 of 21 patients of aplastic anemia treated with FLC showed reconstitution of haemopoietic function or improvement of peripheral blood pictures, while 27 of 30 patients treated with FLCF showed reconstitution or improvement. It is verified that there is a stimulating factor for CFU-CM, BFU-E, and CFU-E and also a immunologic stimulant for improving the nonspecific immunologic function of the organism as shown by clinical analysis and experimental study. It is obvious that the therapeutic effect of FLCF is much better than that of the FLC.

[Role of prostaglandin E in modulation of granulopoiesis by marrow stroma].

The stroma layer (SL) cultured from mouse bone marrow cells for one week, had an inhibitory effect on the granulocyte-macrophage progenitor cells (CFU-GM). The inhibitory effect decreased in the 2nd week SL, while the 3rd week SL promoted CFU-GM growth greatly. When indomethacin (1 x 10(-7) mol/L) was added into the CFU-GM culture system, the score of CFU-GM on the 1st week SL was raised, and on the 2nd week SL was further increased significantly, but it leveled off on the 3rd week SL. The addition of exogenous 10(-8) mol/L PGF1 suppressed the CFU-GM growth on all the 1st to 3rd week SLs. When 1 x 10(-8) mol/L PGE1 was added with 2 x 10(-7) mol/L indomethacin, 1st week SL-CFU-GM increased to 42.61%, 2nd week SL-CFU-GM nearly to 100% of the control. For the 3rd week SL-CFG-GM, 1 x 10(-7) mol/L indomethacin was enough to reverse the inhibition induced by exogenous 1 x 10(-8) mol/L PGE1. It is suggested that definite amount of PGE was produced from cells in the 1st week SL. The secretion of PGE from SL was reduced during 2nd week, and almost stopped in the 3rd week SL. The results indicate that the modulation of granulopoiesis by marrow stroma is, at least partly, mediated by PGE.