Induction of interdigitating reticulum cell-like differentiation in human monocytic leukemia cells by conditioned medium from IL-2-stimulated helper T-cells

Monocytic leukemia (MoL) cells were obtained from the peripheral blood of a patient in whom the leukemic cells infiltrating various lymphoreticular organs exhibited features intermediate between interdigitating reticulum cells (IDC) and ordinary phagocytic macrophages, whereas the leukemic cells in the peripheral blood were essentially monocytic and lacked such features. Peripheral blood CD4+ T-cells were established as an interleukin-2-dependent T-cell line. When the MoL cells were exposed for a few days to conditioned medium from the T-cell line, they extended several dendritic cytoplasmic projections and became intensely positive for HLA-DR antigen, cytoplasmic S-100β protein, and CD1 antigen. Functionally, the conditioned medium significantly down-regulated Fc-mediated and Fc-independent phagocytic activities, and the levels of lysosomal enzymes such as lysozyme and nonspecific esterase in the MoL cells. Moreover, the conditioned medium significantly up-regulated the accessory cell function of the MoL cells as measured by the primary allogenic mixed leukocyte reaction (MLR). Furthermore, the conditioned medium significantly down-regulated the expression of CD14 antigen. Biochemical analysis indicated that the factor responsible for these changes is a protein which is distinct from known human cytokines and whose molecular weight is approximately 31 kDa. These findings suggest that IDC are closely related the monocytic lineage and that helper T-cells play an important role in constructing the microenvironment of T-lymphoid tissues which is necessary for the differentiation and maturation of IDC.     

A minority of 46,XX true hermaphrodites are positive for the Y-DNA sequence including SRY

Summary A total of 30 cases of 46,XX true hermaphroditism was analysed for Y-DNA sequences including the recently cloned gene for male testis-determination SRY. In 3 cases, a portion of the Y chromosome including SRY was present and, in 2 cases, was localised, to Xp22 by in situ hybridisation. Since previous studies have shown that the majority of XX males are generated by an X-Y chromosomal interchange, the Xp22 position of the Yp material suggests that certain cases of hermaphroditism can arise by the same meiotic event. The phenotype in the 3 SRY-positive cases may be caused by X-inactivation resulting in somatic mosaicism of testis-determining factor expression giving rise to both testicular and ovarian tissues. Autosomal or X-linked mutation(s) elsewhere in the sex-determining pathway may explain the phenotype observed in the remaining 27 SRY-negative cases.     

Selective allele loss and interference between cauliflower mosaic virus DNAs

Summary Some cauliflower mosaic virus (CaMV) alleles are selectively lost during growth of the virus in mixedly infected turnip plants. Viral DNA from plants co-inoculated with DNA of the cabbage S isolate and infectious cabbage S DNA with an extra EcoRI restriciion site lacked the extra site. The EcoRI allele was also lost in most plants co-inoculated with a non-infectious mutant of cabbage S DNA while little selective allele loss was observed with two other non-infectious mutant DNAs. Plants co-inoculated with DNAs of closely-related isolates (CM4-184 and W) contained both parental viral DNAs and some DNAs with characteristics of both parents. Interference, scored as a reduced frequency of infection or a delay in symptom appearance relative to plants inoculated with wild-type DNA, occurred when plants were inoculated with wild-type and mutant DNAs covalently attached to one another in partial dimer plasmid DNAs. Similarities in the conditions leading to selective allele loss and those leading to interference suggest that both may have been due to active gene conversion between CaMV DNA molecules.     

Phosphatidyl glycerolphosphate serves as glycerolphosphate donor in polymer synthesis

Phosphatidyl glycerolphosphate was found to serve as the glycerolphosphate donor for polymer synthesis. When CDP-diglyceride and radiolabeled glycerolphosphate were incubated with the membrane enzyme prepared from Streptococcus sanguis, active syntheses of radiolabeled lipids and polymers were observed. The synthesis of polymer was not inhibited by low concentration of unlabeled phosphatidylglycerol. When [3H, 32P]glycerolphosphate was used, the polymer synthesized contained both 3H and 32P. The lipids formed were characterized as phosphatidylglycerol and phosphatidyl glycerolphosphate. The polymers formed from the latter were characterized as lipoteichoic acid like compounds by sodium dodecylsulfate-polyacrylamide gel electrophoresis.     

Cytochrome P-450-catalyzed stereoselective epoxidation at the K region of benz[a]anthracene and benzo[a]pyrene

The enantiomers of K-region benz[a]anthracene (BA) 5,6-epoxide and benzo[a]pyrene (BP) 4,5-epoxide were resolved by chiral stationary-phase high-performance liquid chromatography (CSP-HPLC). The K-region epoxides formed in the metabolism of BA by liver microsomes from untreated (control), phenobarbital (PB)-treated, and 3-methylcholanthrene (MC)-treated male Sprague-Dawley rats were determined by CSP-HPLC to have a 5R,6S/5S,6R enantiomer ratio of 25:75, 21:79, and 4:96, respectively. The K-region 4,5-epoxide formed in the metabolism of BP by the same rat liver microsomal preparations contained a 4R,5S/4S,5R enantiomer ratio of 48:52 (control), 40:60 (PB), and 5:95 (MC), respectively. The results indicate that various cytochrome P-450 isozymes of rat liver exhibit different stereoselective properties in catalyzing the epoxidation reactions at the K region of BA and of BP.     

Polypeptide fragments of the third component of complement in urine of hereditary nephritis patients

Pro-HNP, a urine protein isolated from hereditary nephritis patients, is derived from C3 and resembles the C3c domain. It contains disulfide-linked polypeptides of beta 75, alpha 40, and alpha 28. Plasmin degraded pro-HNP in vitro to HNP, which was also isolated from the urine of patients and which contained disulfide-linked polypeptides of beta 60, alpha 38, and alpha 26, and noncovalently bound polypeptide of beta 17. Amino terminal sequence analyses and amino acid compositions of the seven polypeptides isolated from pro-HNP and HNP show that beta 75 degrades to beta 60 and beta 17 (beta 17 locates at the amino end of beta 75), alpha 40 degrades to alpha 38 (both locate at the carboxyl end of the alpha-chain of C3), and alpha 28 degrades to alpha 26 (both are from the amino end of the alpha'-chain of C3b). These results confirm the enzymatic specificity of plasmin on pro-HNP. In HNP, the half-cystine contents of beta 60, alpha 38, alpha 26, and beta 17 were approximately 3, 12, 3, and 4, respectively. Partial reduction readily released alpha 40 from pro-HNP and alpha 38 from HNP. There were about five intra-chain disulfide bonds in alpha 40 or alpha 38; stepwise reduction of these intra-polypeptide bonds apparently accounted for multiple conformations of alpha 40 or alpha 38.