T-cell lymphoma: a morphological, histochemical and immunological study of nine Chinese cases

Nine cases of T-cell lymphoma presenting in the Guizhou province of China between 1982 and 1984 are reviewed. Seven of the patients were male; seven patients have died, the mean survival period being 22 months. The clinical features resembled those reported in Japanese cases, but skin lesions were absent. Histologically three cases were classified as of lymphoblastic type, three as pleomorphic cell type, two as clear cell type and one as immunoblastic-lymphadenopathy-like T-cell type.

Genetic analysis of the nitrogen fixation system in Klebsiella pneumoniae

Fine structure mapping of nif mutations of Klebsiella pneumoniae was accomplished by means of Pl-transductional crosses and the plasmid R144 drd mediated conjugations. The physical distance between nif mutations based on the percentage of co-transduction with hisD of the nif mutations was estimated. The maximal distance between two mutations was calculated about 3 Kb, and the average distance between different nif mutations was about 1 to 2 Kb. So no "silent region" was shown within the nif cluster nearby the histidine operon. Several hisD-unlinked nif mutants were isolated and investigated genetically and biochemically. They all differed from the glutamineless mutants, one of these mutants was tentatively assigned as a sort of N-assimilation mutant with little activity of glutamate synthetase. It differed from the known N-assimilation mutants in its absence of nitrogenase activity. Since the wild type hisD-linked nif genes carried by the plasmid RP4 failed to complement the defects of the hisD-unlinked nif genes in the recipient cells but they were effective to facilitate E. coli in acquiring the ability to fix nitrogen, which indicates that the hisD-unlinked nif genes necessary for the functioning of the hisD-linked nif genes are present in E. coli.