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81.
A Amar S F Radka S L Holbeck S J Kim B S Nepom K Nelson G T Nepom 《Journal of immunology (Baltimore, Md. : 1950)》1987,138(11):3986-3990
Bgl II restriction endonuclease digestion of genomic DNA from lymphoblastoid cell lines homozygous for HLA DR and DQ serological specificities, followed by hybridization with a DQ alpha cDNA probe, identified a genomic polymorphism characterized by two reciprocal patterns, one associated with DR 3, 5 and 8 and the other with DR 1, 2, 4, 7, and 9. The former pattern corresponded precisely to the reactivity of monoclonal antibody SFR20-DQ alpha 5, shown by Western blotting to react with isolated alpha-chains, but not with beta-chains. Additional variants of the DQ alpha genes were identified by using a locus-specific oligonucleotide probe for the DQ alpha gene, indicating differences among the DQ alpha 5-negative set of alleles. This analysis defines a set of DQ alpha allelic markers that are distinct from the well-established DQ serologic specificities DQw1, 2, 3 or "blank." Although most DQ alpha 5+ cells carry the DRw52 specificity associated with the DR beta 2 gene, analysis of DQ alpha polymorphisms on DR5, DQw1; DR8, DQw1; and DRw13, DQw1 cells verified that this DQ alpha family of alleles was not invariably linked to the DR beta 2 locus. 相似文献
82.
Antibodies to the L3T4 and Lyt-2 molecules interfere with antigen receptor-driven activation of cloned murine T cells 总被引:1,自引:0,他引:1
R L Moldwin W L Havran G J Nau D W Lancki D K Kim F W Fitch 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(3):657-664
When L3T4+ cloned murine helper T lymphocytes (HTL) are stimulated with antigen or immobilized anti-T cell receptor (TCR) monoclonal antibodies (mAb) at concentrations which are optimal for proliferation, anti-L3T4 mAb inhibits activation as measured by proliferation and lymphokine production. Under similar conditions, IL 2-independent proliferation of Lyt-2+ cloned murine cytolytic T lymphocytes (CTL) stimulated by anti-TCR mAb is inhibited by anti-Lyt-2 antibodies. Proliferation of cloned HTL and CTL cells stimulated by IL 2 is not affected by the anti-L3T4 and anti-Lyt-2 mAb. The inhibition of TCR-induced activation of the T cell clones is not due to interference with the binding of the anti-TCR mAb. Stimulation of the TCR has been proposed to induce lymphokine secretion and proliferation by T cells through a pathway involving the activation of protein kinase C and the stimulation of an increase in the concentration of intracellular free calcium. However, proliferation of T cells stimulated by PMA (which activates protein kinase C) plus the calcium ionophore A23187 (which increases the concentration of intracellular free calcium) is not affected by mAb reactive with the Lyt-2 or L3T4 structures. If TCR stimulation does indeed activate T cells by activating protein kinase and increasing intracellular free calcium, then our data suggest that anti-L3T4 and anti-Lyt-2 mAb inhibit TCR-driven proliferation at some step before the activation of protein kinase C and the stimulation of a rise in intracellular free calcium concentration. Our results suggest that anti-L3T4 and anti-Lyt-2 mAb interfere with early biochemical processes induced by stimulation of the TCR. In HTL, which proliferate via an autocrine pathway, anti-L3T4 mAb appears to inhibit proliferation by interfering with signaling events involved in lymphokine production. Inhibition of IL 2-independent proliferation of Lyt-2+ cells by anti-Lyt-2 mAb appears to occur by a different mechanism. The precise molecular basis for the interference of each cell type has not yet been characterized. 相似文献
83.
Stevens suggests a test of fit, based on Bernstein's estimators, of the Hardy-Weinberg law for the ABO system. Nam and Gart extend this test to the generalized ABO-like system and apply it to HLA data. When the recessive gene is rare, Huether and Murphy recall Haldane's point that its Bernstein's estimator is negatively biased and go on to suggest novel corrected versions of it. With the identification of more HLA antigens, it is not uncommon to find, in certain populations, that the sample data contain no double blanks; that is, every individual reacts to at least one antigen for a given locus. Gart and Nam give a simple score test of a zero true recessive-gene frequency for such situations. Here we examine the extended test of Stevens as a test of this hypothesis. We find that it is fully efficient for two codominant alleles but that when the number exceeds two its efficiency may be 50% or lower or as high as 100%, depending on the number of alleles and the pattern of gene frequencies. The tests are applied to a set of HLA data. 相似文献
84.
Victor L. Sylvia Hyeong L. Kim James O. Normanand David L. Busbee 《Cell biology and toxicology》1987,3(1):39-49
Hymenoxon, a toxic sesquiterpene lactone found in bitterweed, bound deoxyguanosine in a cell free system and formed adducts with guanine residues in cellular DNA. The reactive dialdehyde form of hymenoxon formed stable Schiff base products with deoxyguanosine which were separable from unreacted hymenoxon and deoxynucleosides by reverse phase high pressure liquid chromatography. Hymenoxon adducts which eluted as a single impure peak from the octadecylsilane column separated on amino and diphenyl-bonded phases with 10% methanol. Tritiated nucleoside adducts were isolated and purified from CFW mouse sarcoma cells treated with hymenoxon. Proton nuclear magnetic resonance spectra of purified hymenoxon-deoxyguanosine adducts revealed a loss of signals for hydroxyl groups in the bishemiacetal of hymenoxon. 13C-nuclear magnetic resonance spectra revealed that the major adduct has 35 carbon atoms, indicating an interaction of at least two guanine residues per hymenoxon molecule and suggesting that hymenoxon may cross-link DNA. Sedimentation analysis of treated DNA further showed that DNA cross-linking by hymenoxon (30 µg/ml) was equivalent to that of a known cross-linking agent, mitomycin C (7.5 µg/ml). Hymenoxon was more cytotoxic to DNA cross-link repair-deficient Chinese hamster ovary cell mutants than to repair proficient strains. These data combine to indicate that hymenoxon acts as a bifunctional alkylating agent which cross-links DNA in mammalian cells.CHO
Chinese hamster ovary
- HYM
hymenoxon
- MMC
mitomycin C
- NMR
nuclear magnetic resonance
- PBS
phosphate buffered saline 相似文献
85.
Regional mapping panel for human chromosome 17: Application to neurofibromatosis type 1 总被引:34,自引:0,他引:34
A somatic cell hybrid mapping panel was constructed to localize cloned DNA sequences to any of 15 potentially different regions of human chromosome 17. Relatively high-resolution mapping is possible for 50% of the chromosome length in which 12 breakpoints are distributed over approximately 45 megabases, with an average spacing estimated at 1 breakpoint every 2-7 megabases. This high-resolution capability includes the pericentromeric region of 17 to which von Recklinghausen neurofibromatosis (NF1) has recently been mapped. Using 20 cloned genes and anonymous probes, we have tested the expected order and location of panel breakpoints and confirmed, refined, or corrected the regional assignment of several cloned genes and anonymous probes. Four markers with varying degrees of linkage to NF1 have been physically localized and ordered by the panel: the loosely linked markers myosin heavy chain 2 (25 cM) to p12----13.105 and nerve growth factor receptor (14 cM) to q21.1----q23; the more closely linked pABL10-41 (D17S71, 5 cM) to p11.2; and the tightly linked pHHH202 (D17S33) to q11.2-q12. Thus, physical mapping of linked markers confirms a pericentromeric location of NF1 and, along with other data, suggests the most likely localization is proximal 17q. 相似文献
86.
Molecular cloning of an endoglucanase gene from an alkalophilic Bacillus sp. and its expression in Escherichia coli. 总被引:1,自引:0,他引:1
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One of the cellulase genes from alkalophilic Bacillus sp. strain N-4 was cloned in pBR322. A recombinant plasmid, pYBC107, expressing carboxymethyl cellulase (CMCase) was isolated, and the size of the cloned HindIII fragment was found to be 5.5 kilobases. The restriction map of pYBC107 showed a different pattern from those of pNKI and pNKII (N. Sashihara, T. Kudo, and K. Horikoshi, J. Bacteriol. 158:503-506, 1984). When the HindIII fragment from pYBC107 was subcloned into pYEJ001, there was a 3.8-fold increase in CMCase activity over that observed with pYBC107. Plasmid pYBC108 constructed by treatment of pYBC107 with HindIII and EcoRI expressed the CMCase activity, although to a limited extent. To verify the originality of cloned pYBC107 from Bacillus sp., we analyzed the restriction digest by Southern blotting. 相似文献
87.
Latika P. Chanderkar Gouri Shanker Robert L. Knobler Fred D. Lublin Woon Ki Paik Sangduk Kim 《Neurochemical research》1987,12(5):445-449
Mice with the dysmyelinating mutation shiverer were studied by measuring the activity of two protein methylases and myelin marker enzymes in the brain. It was observed thatS-adenosylmethionine: protein-lysineN-methyltransferase (protein methylase III, EC. 2.1.1.43) activity is significantly reduced in phenotypically affected homozygous shiverer (shi/shi) mutant mouse brain compared to the unaffected heterozygous littermate brain. This reduction in enzyme activity is manifested mainly by reduced formation of trimethyllysine during the in vitro methylation of histone. In contrast, myelin marker enzymes such as 2,3-cyclic nucleotide 3-phosphohydrolase and 5-nucleotidase as well asS-adenosyl-methionine: protein-carboxylO-methyltransferase (protein methylase II, EC. 2.1.1.24) activities were not significantly affected in these strains of mice. 相似文献
88.
Picosecond transient absorption changes, with a laser intensityas low as one photon absorbed per single reaction center, weremeasured with vitamin K1-depleted and P700-enriched particleswhich were obtained by ether treatment of spinach PS-I particles.When P700 was in the oxidized state, a bleaching that correspondedto about one-seventh of the ground state absorption was observedjust after a laser flash (0 picosecond delay). A major partof the bleaching decayed with a lifetime of about 35 picoseconds,which corresponds to the relaxation of the excited antenna chl-ato the ground state. By contrast, when P700 was in the reducedstate, the bleaching observed at a 0 ps delay was broader, especiallyon the longer wavelength side than the ground state absorption,probably because of the generation of the excited state of P700.About one half of the bleaching decayed within 35 ps and theremaining half, which had a broad spectrum and a peak around682 nm, was conserved up to 2 ns. This long-lived bleachingprobes no picosecond decay of the radical pair P700+-A0because electrons were not transferred from A01 to A1 in vitaminK1-depleted particles. After addition of vitamin K3, an analogof vitamin K1, to the reduced particles, the bleaching around685 nm decayed successively with an apparent rate of about 150picosecond, while the bleaching around 700 nm was conservedfor up to 2 nanosecond. Thus, the bleaching remaining at 2 nsresembled the difference spectrum of P700, suggesting a subnanosecondquenching of A01 by the externally added vitamin K3. These observationssupport a recent proposal that the secondary electron acceptorA1, in photosystem I, is vitamin K1.
3Permanent address: Optics Laboratory, Korea Standards ResearchInstitute, Daedok Science Town, Chungnam 300-31, Korea. (Received October 24, 1988; Accepted April 14, 1989) 相似文献
89.
The AIDS epidemic has transformed the importance of cytomegalovirus (CMV) as a pathogen for the adult human central nervous system (CNS). At autopsy, about 25 percent of AIDS cases have cytopathologic evidence of CNS infection by CMV. Since almost nothing is known of the host CNS-viral interactions, we have developed a laboratory model of CMV infection of the brain in the guinea pig. In the present paper, we review the syndromes of CMV infection of the human CNS and compare the neuropathological findings of the opportunistic CMV brain infection in AIDS with the model. Destructive meningoencephalitis, perivascular infiltrates, and subependymal inflammation are found in both, but the glial nodule is the most characteristic feature of each. Thus, we demonstrate that the model faithfully reflects the histopathology of the human disease. Furthermore, since we have found that CNS infection is achieved following systemic infection in the guinea pig, the model recapitulates the sequence of infection in humans. 相似文献
90.
Urinary gonadotropin fragment (UGF) measurements in the diagnosis and management of ovarian cancer 总被引:1,自引:0,他引:1
UGF is a small peptide present in the urines and tissues of patients with gynecologic cancers. Published research (which, at present, mainly comes from our laboratory) on the general application of UGF as a tumor marker, and on its use in the diagnosis of ovarian cancer, is reviewed, and new studies on its use, alone and with CA125, in the management of patients with ovarian cancer, are presented. In 234 healthy women, 89 with benign disease, and 79 with ovarian cancer, UGF levels were above 3 fmol/ml (low cut-off) in 12 percent, 7 percent, and 82 percent, respectively, and above 8 fmol/ml (high cut-off) in 1.7 percent, less than 1.1 percent, and 59 percent, respectively. Similarly, 11 percent, 14 percent, and 70 percent, respectively, had CA125 levels above 35 U/ml (low cut-off), and less than 1.9 percent, 1.2 percent, and 49 percent had levels above a 200 U/ml (high cut-off). Ideally, the higher UGF and CA125 cut-offs should be used for diagnostic applications, like differentiation of a benign from a malignant pelvic mass (false-positive rate: UGF, less than 1.1 percent; CA125, 1.2 percent), but raising the cut-offs diminishes sensitivities for malignancy (UGF, 59 percent; CA125, 49 percent). The populations detected by the two markers only partially overlap, however, so that, together, UGF or CA125 can identify 75 percent of malignant pelvic masses. Levels of UGF (cut-off, greater than 3 fmol/ml) and CA125 (35 U/ml) were also monitored in 30 women undergoing therapy for ovarian cancer. Clinical observations were reflected at each clinic visit by UGF alone in 67 percent, by CA125 alone in 57 percent, and by UGF and CA125 together in 87 percent of cases. While separately UGF and CA125 levels predicted 71 percent and 57 percent, together they forecast 86 percent of recurrent cancers prior to clinical manifestations. UGF and CA125 should be used together in the detection and management of ovarian cancers. 相似文献