Orientation of Giemsa C-bands in interphase cells of Allium cepa L.

Summary Orientation of Giemsa C-bands in Allium cepa was studied in both mitotic and interphase cells. It has been shown that telophase orientation of the chromosome is maintained throughout the interphase and early prophase. It has been assumed that this non-random orientation is due to anchorage of the telomeres with the nuclear membrane. Contrary to earlier observations, 2 by 2 pairing of the telomeres could not be traced in this species.     

delta-9-Tetrahydrocannabinol (THC) inhibition of the membrane transport system for thymidine]

THC decreases 3H-thymidine uptake within 15 sec. after addition of the drug to the culture (L1210 murine lymphoma cells and human lymphocytes). Experiments performed at 0 degrees C indicate that THC has no action on thymidine binding to the carrier. THC in micromolar concentration inhibits DNA synthesis through a alteration of membrane configuration.     

Long-term depression of two primary immune responses induced by a single dose of 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC)

Summary 2 primary immune responses (anti-SRBC antibody response and allograft rejection) have been tested in mice at various time intervals after single doses of either DTIC or cyclophosphamide. The DTIC-induced immunodepression proved to be extremely long-lasting, being still detectable after 2 months.This work was supported by Project NO1-CB 64054 of the U.S.-Italy Cooperative Science Program.     

Effect of low density lipoprotein and high density lipoprotein on sodium dodecyl sulphate precipitation of very low density lipoprotein from human serum

Summary In the presence of low density lipoprotein, the sodium sodecyl sulphate(SDS)-very low density lipoprotein(VLDL) complex sedimented, while in the presence of high density lipoprotein the complex floated. This SDS-VLDL aggregate floats at serum triglyceride to cholesterol ratio of 0.7–0.9 and sediments at a ratio of 0.2–0.5.     

Purification and structural characterisation of human HLA-linked B-cell antigens.

The human B cell-specific alloantigen which is closely linked genetically to HLA contains two non-covalently associated, sialogycoprotein subunits of molecular weight (MW) 29,000 (p29), and 34,000 (p34). Although p29 and p34 have different amino-terminal sequences, their tyrosine peptide maps indicate considerable similarity in other portions of their polypeptide chains. Thus the genes for their proteins may have evolved by duplication of a common ancestral gene. Another lymphocyte cell surface protein of MW 16,000 (p16) has also been characterised. Both p16 and p44 (the heavy chain of HLA-A,B antigens) have been compared with p29 and p34.