Fine structure of human- and monkey-derived type C virus particles in monkey lymphoid cell lines expressing adult T-cell leukemia-associated antigens

Summary Ultrastructures of Japanese monkey(Macaca fuscata)-derived type C virus particles in a monkey lymphoid cell line, expressing adult T-cell leukemia (ATL)-associated antigens, are indistinguishable from those of human ATL-associated virus in human and monkey cell lines.With 6 Figures     

ESTABLISHMENT and CHARACTERISTICS OF A HUMAN PANCREATIC CANCER CELL LINE (HGC-25)

A floating cell line (HGC-25) was established from the metastatic ascitic fluid of a human pancreatic adenocarcinoma of ductal cell origin. The cell line was characterized by the growth in suspension with a doubling time of 15.6 hr, a high cloning efficiency in soft agar and a modal chromosome number of 72. Electron microscopic examination revealed terminal bars in a small number of cells. Production of mucin and immunoglobulins and phagocytosis were not demonstrated. Heterotransplantation of the cells produced tumors, being undifferentiated carcinoma histologically. These characteristics mentioned above confirm that HGC-25 cell line is a human pancreatic cancer ceU line.     

Stereochemistry of the copolymerization of carbon dioxide with optically active phenylepoxyethane

The stereochemistry of the copolymerization of optically active phenylepoxyethane ( 5 ) with carbon dioxide using a diethylzinc/water system as catalyst was investigated. The optically active copolymer, poly(oxycarbonyloxy-2-phenylethylene) ( 1 ), was hydrolyzed and the oxy-2-phenylethylene unit was isolated in the form of 1,2-bis(trimethylsilyloxy)-1-phenylethane ( 3 ). The determination of the optical activity of this ether led to the conclusion that the ring opening of 5 takes place predominantly at the methineoxygen linkage accompanying an inversion in the copolymerization. This fact is in sharp contrast with the stereochemistry of the copolymerization of carbon dioxide with 1,2-epoxypropane in which the ring opening takes place at the methylene-oxygen linkage.     

Copolymerization of N-carboxy-γ-benzyl-L-glutamate anhydride and alkylene oxides by organometallic compounds

Copolymerization of N-carboxy-γ-benzyl-L -glutamate anhydride and ethylene oxide or DL-propylene oxide was carried out in the presence of triethylaluminum or diethylzine as catalyst with (or without) dioxane as solvent. From the data obtained by nuclear magnetic resonance spectroscopy, optical rotatory dispersion measurements, infrared absorption spectroscopy and turbidimetry, it was concluded that the copolymer obtained by the triethylaluminum catalyst consisted of two parts, peptide-block part and random or alternate part, while diethylzinc catalyst resulted in the formation of a less random copolymer only. In dioxane, formation of peptide-block part by triethylaluminum was suppressed to some extent.     

Nodular alteration of the paracortical area. An in situ immunohistochemical analysis of primary, secondary, and tertiary T-nodules.

With the use of in situ immunohistochemical techniques on freshly frozen and paraffin-embedded material from 63 reactive lymph nodes, the cellular composition of T-nodules observed in 30 cases with nodular alteration of the paracortical area was analyzed. T-nodules were composed of S-100 beta + interdigitating reticulum cells (IDRCs), variable numbers of OKT6+ dendritic cells (DCs), high endothelial venules, and a very high T helper/T suppressor ratio because of an enrichment of OKT4+, Leu3a+ helper/inducer T cells in these nodules. According to their localization in the paracortical area, and the arrangement of IDRCs and high endothelial venules, T-nodules could be divided into "primary" and "secondary" T nodules. In all cases of dermatopathic lymphadenitis, very large aggregates of S-100 beta + and OKT6+ DCs, admixed with few high endothelial venules and variable numbers of OKT4+, Leu3a+ helper/inducer T cells, were observed and were termed "tertiary T-nodules." It is suggested that T-nodules represent the paracortical counterparts of B-lymphoid follicles and are the in vivo equivalents of DC/T-cell clusters observed in vitro. According to their cellular composition and localization in the lymph node, "primary" and "secondary" T-nodules probably represent subsequent maturation stages of distinctive nodular paracortical structures, which play an important role in the presentation of antigens to helper/inducer T cells and in the proliferation of antigen-responsive T cells. Their close topographic relationship to B-lymphoid follicles may indicate their role in the extrafollicular generation of antibody-forming cells.     

Histamine downregulates CD14 expression via H2 receptors on human monocytes

Lipopolysaccharide (LPS) binds to LPS-binding protein (LBP) in plasma and is delivered to the cell surface receptor CD14 on human monocyte. LPS is transferred to the transmembrane signaling receptor toll-like receptor (TLR) 4. In the present study, the effect of histamine on the expression of CD14 on human monocytes was investigated. Histamine concentration- and time-dependently decreased the expression of cell surface CD14, whereas histamine did not decrease mRNA for CD14 nor increase soluble CD14 (sCD14). The inhibitory effects of histamine on CD14 expression were antagonized by H2-receptor antagonist, but not by H1 and H3/H4 antagonist. The effects of selective H2-receptor agonists, 4-methylhistamine and dimaprit, on CD14 expression mimicked that of histamine indicating that histamine regulated CD14 expression through the stimulation of H2-receptors. The pretreatment with histamine partially inhibited the LPS-induced TNF-alpha production in human peripheral blood mononuclear cells (PBMC). Such inhibition might be due to the down-regulation of CD14 expression on monocytes by histamine.