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1.
Michael Steinitz Alejandro Livoff Sara Tamir Talma Brenner 《Medical oncology (Northwood, London, England)》1993,10(1-2):49-52
A universal method for selection of surface marker-positive cells is described. The cells, admixed with an excess of surface marker-negative cells, are In-st labelled with a specific biotinylated ligand and then isolated with the aid of monoclonal, anti-biotin coated beads. The method enables selection and isolation of cells with a frequency as low as 10-4. The ligand can be an antigen (for selection of infrequent antibody-producing cells), an antibody (for selection of surface antigen-positive cells) or other molecules (for selection of specific receptor-positive cells). 相似文献
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Teresa Pelissier Carlos Paeile Rub n Soto-Moyano Hern n Saavedra Alejandro Hern ndez 《European journal of pharmacology》1990,190(3):287-293
The antinociceptive activity of the selective k opioid agonist U-50,488H, given intrathecally (i.t.) against chemically induced cutaneous pain in rats, was assessed from cumulative dose-response experiments and the formalin test. Three successive i.t. doses of 5, 10 and 35 nmol of U-50,488H produced a gradual reduction of pain scores which was statistically significant at all observation periods. This effect was antagonized significantly by 3 mg/kg i.p. of the opiate antagonists, naloxone and WIN 44,441-3. The analgesia profile showed a clear dose-response relationship. A dose producing 50% ‘maximum posible analgesia’ of 6.20 nmol (95% confidence interval: 3.05–12.59 nmol) was calculated. The results indicated that cutaneous pain of a chemical/inflammatory nature is highly sensitive to activation of k receptors of the spinal cord dorsal horn. 相似文献
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Pablo L. Joskowicz Alberto Muoz Julio Barrera Alejandro J. Müller 《Macromolecular chemistry and physics.》1995,196(1):385-398
Preparative temperature rising elution fractionation (TREF) on commercial linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) samples has been performed. The resulting fractions exhibited a bimodal and a unimodal distribution, respectively. Two LLDPE fractions of low (5 CH3/1000 C) and high (21 CH3/1000 C) short-chain branching content were solution-mixed with the LDPE central fraction (16 CH3/1000 C). Indirect evidence based on differential scanning calorimetry results suggest that the fractions with similar branch contents are more miscible than those with dissimilar ones. 相似文献
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The DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) procedure was used to analyze DNA single-strand breaks (SSBs) and alkali-labile sites induced by exposure to the nitric oxide (NO) donors sodium nitroprusside (SNP) and 3-morpholinosydnomine hydrochloride (SIN-1) in the whole genome and in long interstitial telomeric repeat sequence (ITRS) blocks from Chinese hamster cells. The relative density of DNA damage generated in the ITRS by X-rays was similar to that induced in the genome overall, whereas it was 1.7 times higher when the alkylating agent MNNG was assayed. Nevertheless, after SNP or SIN-1 treatment, ITRSs proved to be 2.8 and 2.7 times relatively more damaged, respectively, than the whole genome. When the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) was not active, as in XR-C1 mutant cells, the repair kinetics in the whole genome did not differ from that in the parental cell line with X-ray or SNP exposure. However, whereas the SSBs and alkali-labile sites induced in the ITRS by X-rays exhibited rejoining kinetics similar to that of the parental cell line, the damage induced by SNP was more slowly rejoined. This implies a role for DNA-PKcs in the repair of DNA damage induced by NO, especially in ITRSs. The results demonstrated intragenomic heterogeneity of NO-induced DNA damage and repair; there was a higher density of DNA damage in the ITRS blocks, possibly because of their guanine richness. This suggests that a parallel process may occur in the terminal telomeres, which has implications for premature aging and neoplastic development by chronic NO exposure in vivo. 相似文献
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Jos Alejandro Lpez Jonathan H. Lebowitz Stephen M. Beverley Hans-Georg Rammensee Peter Overath 《European journal of immunology》1993,23(1):217-223
The question is addressed whether antigens of Leishmania, a parasite residing in the endosomal compartment of macrophages, can be presented in the context of major histocompatibility complex class I molecules. We used E. coli β-galactosidase as a model antigen which can be expressed in high levels in L. mexicana promastigotes (L. mexicana-gal). Infection of BALB/c mice with L. mexicanagal induces β-galactosidase-specific cytotoxic T cells (CTL), which can be isolated using a β-galactosidase-expressing mastocytoma line as an antigen-presenting cell. These CTL recognize epitopes of β-galactosidase in the context of H-2Kd; however, they do not recognize L. mexicanagal-infected macrophages even after killing of the intracellular amastigotes by drug treatment or macrophage activation by lymphokines, although class I-peptide interaction and the presentation of endogenously produced antigens is normal. It is concluded that parasite antigens can induce a CTL response in vivo but that these CTL cannot recognize infected macrophages because the relevant epitopes cannot gain access to class I molecules. The effect of priming in vivo may be explained by the well-known but ill-understood phenomenon of cross-priming. 相似文献