No abstract

One hundred twenty-five cases of Hodgkin's disease from the United States (79), Mexico City (31), and Costa Rica (15) were analyzed for the presence of Epstein-Barr virus (EBV) by in situ hybridization to EBER1 transcripts. EBV was more frequently detected in the Reed- Sternberg (RS) cells of mixed cellularity Hodgkin's disease (37 of 48 [77%]) compared with the nodular sclerosis subtype (19 of 71 [27%], P < .001). The presence of EBV was also associated with Hispanic ethnicity (P < .001). In a multivariate analysis, patient age, gender, and geographic location were less predictive of EBV positivity than were mixed cellularity histology (odds ratio = 8.3) and Hispanic ethnicity (odds ratio = 4.3). Southern blot analysis of EBV terminal repeat fragments using the Xho1a probe showed that the viral DNA was monoclonal in 17 of 17 cases having EBER1-positive RS cells. By comparison, EBV DNA was not detected by Southern analysis in 20 cases lacking EBER1 in RS cells, even when occasional background lymphocytes expressed EBER1. Because clonal viral DNA was so readily detected in EBER1-positive cases, the EBV genome is probably amplified at least 50- fold in the infected RS cells. Monoclonality of EBV DNA implies that the RS cells were infected before malignant transformation.

No abstract

Rabbit kidney tissue either from normal rabbits or from rabbits “programmed” by phlebotomy or varying periods of hypoxia was cultured and shown to release into the culture medium an erythropoietically active substance. The cultures established from rabbits programmed by 6- 12 hr of hypoxia yielded the highest levels of erythropoiesis- stimulating activity.

Granulocytic (colony-forming units in culture, or CFU-c) and erythrocytic (erythropoietin-responsive cells, or ERC) progenitor cells in canine cyclic hematopoiesis (CH) have been shown to fluctuate over the cycle and in the same phases as one another. The ERC cycle is preceded by 3 or 4 days by a rise in serum erythroid-stimulating activity and is followed by a reticulocytosis. During the cycle CFU-c show a differential sensitivity to two sera, one normal and one containing elevated amounts of colony-stimulating activity. The proliferation rate of CFU-c also fluctuates from well above normal to considerably less than normal over the cycle. These results are discussed in the light of present knowledge of the pathogenesis of canine CH. We suggest that these results support the contention that CH is a disorder of hemopoietic stem cells and that the cycling of humoral factors and peripheral blood cells may follow as a consequence.