Characterisation of stroma-dependent blast colony-forming cells in human marrow

Human bone marrow contains a population of haemopoietic progenitor cells that can be distinguished by their ability to adhere to preformed stromal layers (cultured in the presence of methylprednisolone [MP+] and form blast cell colonies. The stromal layers function in the colony assay after they have been heavily irradiated but not after they have been passaged. The binding of the progenitor cells to the stromal cells is complete after 2 hours of coincubation, and stromal layers of 9.6 cm2 can provide adhesion sites for at least 2,000 blast colony-forming cells. The blast colony-forming cells were shown by micromanipulation to self-renew as well as to give rise to multipotential and lineage-committed colony-forming progenitor cells.     

Intraspecific variation in reproductive physiology and egg quality in the European Starling Sturnus vulgaris

Egg mass shows large intraspecific variation in birds and is repeatable within individuals. The mechanisms underlying this variation are unknown. We hypothesized that measures of egg quality (the mass of yolk protein, yolk lipid, and albumen protein) would be positively correlated with the plasma pools of the yolk precursor vitellogenin, and the masses of the oviduct, metabolic machinery (liver, heart, lungs, kidneys, gizzard, small intestine and pancreas), and endogenous stores of protein and lipid. We tested these predictions in European Starlings Sturnus vulgaris collected at the peak of egg production effort. In contrast to our predictions, both yolk protein and yolk lipid were negatively correlated with plasma vitellogenin levels. Albumen protein was positively related to oviduct mass, but other aspects of body composition failed to explain variation in egg quality. Hence, while we observed correlations between egg composition and peripheral systems (circulating precursor pools and the oviduct), we found no evidence that egg quality is determined by more general processes, i.e., the supply and processing of nutrients.     

Polymorphisms of DQ β genes in HLA-DR4 haplotypes from healthy and diabetic individuals

The restriction fragment length polymorphism (RFLP) of DQ was assessed in a panel of control and insulin-dependent diabetes (IDD) patients who were serologically typed as HLA-DR4 homozygotes or HLA-DR3, DR4 heterozygotes. Digestions of genomic DNA with Barn HI, Bg1 II, Pst I, Xba I, and Hind III revealed a total of 15 RFLPs in the panel of 71 HLA-DR4 chromosomes. These RFLPs were organized into six allelic groups on the basis of segregation analysis in families. Complete RFLP haplotypes for the 5 restriction enzymes could be constructed for 42 of the HLA-DR4 chromosomes. This analysis revealed 18 RFLP haplotypes of DQ associated with the DR4 chromosomes tested. Two of these haplotypes, designated DQ3.DR4.a and DQ3.DR4.b, accounted for over 50 % of the DR4 chromosomes analyzed. These two haplotypes were antithetical for the RFLPs detected by all five enzymes, indicating that they represent very distinct forms of DQ . The remaining 16 haplotypes were infrequent or unique and were closely related to either a DQ3.DR4.a or DQ3.DR4.b. Two of the RFLPs detected, a 5.8 kb Bg1 II fragment and a 10.5 kb Barn HI fragment, had increased frequencies in disease-associated chromosomes. However, none of the RFLPs we detected exhibited a statistically significant increase in IDD or control populations. In contrast, the DQ3.DR4.b DQ haplotype was significantly decreased in IDD-associated DR4 chromosomes. (P=0.04). These results suggest that the DQ3.DR4.b DQ allele may be protective for the development of IDD.