Protoporphyrins modulate voltage-gated Ca current in AtT-20 pituitary cells.

1. Zinc-protoporphyrin-IX (ZnPP-IX) is an inhibitor of the enzyme heme-oxygenase-2 (HO-2) and consequently has been used to examine the role of carbon monoxide production in neural tissues. We have measured voltage-gated Ca current in AtT-20 pituitary cells using the whole-cell patch-clamp technique and have assessed the effects of extracellularly applied ZnPP-IX and related compounds.

Serological grouping of indigenous Bradyrhizobium sp. (Arachis) isolated from various soils of Thailand.

ELISA and antibody adsorption tests were applied to determine the minimal somatic antigen constitution of 243 strains of Bradyrhizobium sp. (Arachis) using 12 antisera. The 243 indigenous bradyrhizobial isolates were from 15 sites in four regions of Thailand.

HDS: Establishment of a New Cell Line from a Hairy Cell Leukemia Patient with Resistance to Alpha-Interferon Therapy.

A new cell line, designated "HDS", was established in a suspension culture derived from the peripheral blood of a patient with hairy cell leukemia (HCL) who developed clinical resistance to alpha-interferon (aIFN) therapy. The patient exhibited a clinical picture characteristic of HCL, including splenomegaly, cytopenias, and tartrate-resistant acid phosphatase (TRAP)-positive "hairy" cells in blood and marrow. Chromosomal studies revealed that the cultured cells possess the chromosomal abnormality +12.

B-cell growth factor-induced and alpha-interferon-inhibited proliferation of hairy cells coincides with modulation of cell surface antigens.

alpha-Interferon (IFN-alpha) induced unique ultrastructural alterations in peripheral blood and splenic hairy cell leukemia (HCL) cells (14 of 20 cases) treated in vitro. To further investigate the effects of B-cell growth factor (BCGF) and IFN-alpha on target hairy cells (HCs), we utilized immunogold labeling in conjunction with scanning electron microscopy. This methodology, in contrast to other immunological methods, facilitated direct view of the expression, density, and rearrangement of selected antigens/receptors on individual cells before and after BCGF or IFN-alpha treatment.

Involvement of HLA Antigens, Interleukin 2 Receptor and B-Cell Growth Factor in Interferon Action in Hairy Cell Leukemia.

Little is known about the mechanism(s) by which alpha-interferon (aIFN), when used as a biotherapeutic agent, suppresses the malignant cells and restores the normal phenotype of cells in patients with hairy cell leukemia (HCL). In previous studies using scanning electron microscopy (SEM) we found that alFN induced unique membrane alterations in target hairy cells in vitro. In addition, aIFN was shown to enhance the expression of HLA class II antigens on HCL cells, to induce the production of new proteins in such cells, and to lower the high levels of soluble IL-2 receptors in the serum of HCL patients.