Micro determination of unsaturated disaccharide formed by the action of acidic glycosaminoglycan-endoeliminases. An application of the thiobarbituric acid method to the assay of D-gluco-4-enepyranosyluronic acid-containing disaccharides.

An improved method is described for the micro determination of acidic glycosaminoglycans after digestion with chondroitinase-ABC and -AC. The determination is based on the color production of D-gluco-4-enepyranosyluronic acid-containing disaccharides produced by the action of chondroitinase-ABC and -AC (acidic glycosaminoglycans-endoeliminase) when the periodate-thiobarbituric acid method is applied to the alpha,beta-unsaturated disaccharides. Suitable conditions for the quantitative assay are described.     

Enhancement of erythroid progenitor cell growth in medium conditioned by a human cancer cell line, KONT

Erythroid-potentiating activity (EPA) was detected in culture medium conditioned by a human cancer cell line (KONT) that produces colony-stimulating activity (CSA), using erythroid colony formation in vitro. EPA in the medium conditioned by the KONT cells (KONT-CM) was markedly heat stable. After treating KONT-CM at 80 degrees C for 30 min, 30% EPA remained, while CSA was completely inactivated. Both EPA and CSA appeared in approximately the same fractions of the gel filtration, indicating a molecular weight of approximately 30,000 daltons. EPA bound partially to Concanavalin-A Sepharose, whereas CSA almost did not bind. Our results indicate that EPA can be separated from CSA based on heat stability and binding to Concanavalin-A Sepharose.     

Anti-parasite activity of nucleoside analogues: the metabolism of carbocyclic inosine in promastigotes of Leishmania tropica and Leishmania donovani and its activity against amastigotes of Leishmania donovani in vitro

Carbocyclic inosine is a potent inhibitor for the growth of the promastigote form of Leishmania tropica and Leishmania donovani. In culture, the EC50 values of carbocyclic inosine are 8.3 X 10(-8) and 1.3 X 10(-7) M for the promastigotes of L. tropica and L. donovani, respectively. On the other hand, it is less toxic towards mouse mammary tumor FM3A cells: the EC50 value is 2.7 X 10(-4)M. Carbocyclic inosine is metabolized by Leishmania promastigotes to give carbocyclic adenosine-5'-triphosphate(aristeromycin-5'-triphosphate) and carbocyclic guanosine-5'-triphosphate. This metabolic conversion provides a mechanism for the parasite-selective toxicity of carbocyclic inosine. Carbocyclic inosine was found to be active against L. donovani amastigotes in an in vivo-like cultivation in vitro.     

The Epstein-Barr Virus BDLF4 Gene Is Required for Efficient Expression of Viral Late Lytic Genes

Epstein-Barr virus (EBV) is a gammaherpesvirus, associated with infectious mononucleosis and various types of malignancy. We focused here on the BDLF4 gene of EBV and identified it as a lytic gene, expressed with early kinetics. Viral late gene expression of the BDLF4 knockout strain was severely restricted; this could be restored by an exogenous supply of BDLF4. These results indicate that BDLF4 is important for the EBV lytic replication cycle, especially in late gene expression.     

Effect of moxisylyte hydrochloride on isolated human penile corpus cavernosum tissue

The effect of moxisylyte hydrochloride on isolated human penile corpus cavernosum tissue was investigated and compared with other a-adrenergic antagonists. Moxisylyte produced a concentration-dependent relaxation of a norepinephrine-induced (1 x 10(-5) M) contraction of the corpus cavernosum tissue. Pretreatment with 1 x 10(-6) M doses of moxisylyte reduced competitively the norepinephrine-induced contraction. The competitive effect of prazosin was strongest among four tested agents, followed by phentolamine, moxisylyte, and then yohimbine. The activity ratio for each antagonist is 2.4 for moxisylyte, as compared with 28.2 for prazosin, 6.7 for phentolamine, and 1.6 for yohimbine respectively. Moxisylyte hydrochloride is an agent with potential clinical and research uses capable of producing erection when injected intra-cavernously.     

The Lyb-3+5+ subset of B cells is not required for lupus-like autoantibody formation caused by graft-vs-host reaction

We asked the question whether or not the Lyb-3+5+ B cell subset, which is lacking in CBA/N immune defective mice, is required for the lupus-like autoantibody formation caused by graft-vs-host reaction (GVHR). (CBA/N X DBA/2)F1 male defective mice injected with DBA/2 T cells produced IgG autoantibodies to the same extent as did nondefective F1 mice suffering from GVHR. Although a very small number of DBA/2 B cells might have contaminated the T cell inocula, it was shown that these were B cells of the defective F1 mice that produced autoantibodies during the GVHR. This was demonstrated by detecting autoantibodies carrying an immunoglobulin allotype of the F1 recipient. Furthermore, the defective F1 male mice injected with CBA/N lymphoid cells, which were lacking Lyb-3+5+ B cells, also produced autoantibodies. Isotype analysis of antinuclear antibodies revealed that some of them belonged to IgG3 isotype. It was concluded that the ontogenically late-appearing B cell subset is not required for GVH autoimmunity.