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51.
A simple procedure is described for the elimination ofO-linked glycans from bovine submaxillary mucin under non-reducing conditions, using triethylamine in aqueous hydrazine. The glycans were isolated as the hydrazones, which were converted to the reducing glycans by exchange with acetone in neutral aqueous solution. The glycan alditols obtained after reduction corresponded to those obtained by the reductive -elimination ofO-glycans. 相似文献
52.
Poly(ADP-ribose): Historical perspective 总被引:2,自引:0,他引:2
53.
James E. Talmadge John D. Jackson Claudia D. Borgeson Greg A. Perry 《Cancer immunology, immunotherapy : CII》1994,39(1):59-67
In these studies, we examined the effect of a maximum-tolerated, split-dose chemotherapy protocol of cyclophosphamide, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea carmustine on neutrophil and lymphocyte subpopulations in the peripheral blood (PBL), thymus, bone marrow and spleen. It was found that this protocol of polychemotherapy, modeled after the induction protocol used with autologous bone marrow transplantation for breast cancer, suppressed both B and T cell populations and T cell function at times when the absolute neutrophil count had returned to normal or supernormal numbers. In the peripheral blood, 7 days following initiation of chemotherapy, there was a twofold increase in the percentage of granulocytes as compared to the level in control animals on the basis of a differential count. The polymorphonuclear neutrophil (PMN) frequency in the bone marrow was increased on day 14 and statistically identical to that in control mice on all other days analyzed. In contrast to the bone marrow cells and PBL on day 7, the frequency of PMN in the spleen and thymus was depressed. B cells (B220+) were depressed in the PBL, spleen and bone marrow and took 18–32 days to return to their normal frequency, while the frequency of B cells in the thymus was increased owing to a loss of immature T cells. The percentage of CD3+ cells in the thymus, spleen and bone marrow was significantly increased and required 10–18 days to return to normal levels, while the absolute number of CD3+ cells in the blood varied around the normal value. The ratio of CD4+ to CD8+ cells in all the organs studied varied only slightly owing to a similar reconstitution of CD4+ and CD8+ cells. In contrast to the phenotypic recovery of the CD3+, CD4+ and CD8+ cells, the ability of the splenic lymphocytes to respond to concanavalin-A was depressed and remained depressed, despite the phenotypic reconstitution of the T cell subsets, on the basis of both percentage and absolute cell number. These results show a selective T and B cell depression following multi-drug, split-dose chemotherapy in tissue and blood leukocyte populations and a chronic depression in T cell function. 相似文献
54.
Michael R. Pranzatelli 《Neurochemical research》1994,19(3):311-315
To study the early effects of neonatal 5,7-dihydroxytryptamine lesions on 5-hydroxytryptamine1A (5-HT1A) receptors, we measured regional [3H]8-OH-DPAT-labeled 5-HT1A sites in binding assays and compared them to our previous studies of [3H]paroxetine-labeled 5-HT transporter sites during the first month in the same rats. While there were significant time- and dose-dependent effects of 5,7-DHT on 5-HT transporter sites, there were no significant changes in 5-HT1A sites in cortex, hippocampus, diencephalon, brainstem, cerebellum, or spinal cord. 5,7-DHT lesions also did not alter the Ki of Gpp(NH)p at brainstem 5-HT1A sites or the Ki of 5-HT in cortex or brainstem in the presence or absence of GTPS or Gpp(NH)p. There were significant regional differences between the density of 5-HT1A sites and 5-HT transporter sites. The ontogeny of brainstem 5-HT1A sites was a pattern of increases until three weeks postnatal, and 5,7-DHT lesions did not alter the ontogeny of 5-HT1A sites. These data suggest differential plasticity of 5-HT1A and 5-HT transporter binding sites during the first month after neonatal 5,7-DHT lesions. 相似文献
55.
56.
Sieghart Sopper Susanne Hemm Jürgen Meixensberger Cheik Coulibaly Christiane Stahl-Hennig Gerhard Hunsmann Bernhard Fleckenstein Volker ter Meulen Rüdiger Drries 《Journal of medical primatology》1993,22(2-3):138-146
Paired sera and CSF samples were collected from SIVmac-infected macaques. Animals infected with SIVmac251 maintained low gag and high env-specific antibody levels in plasma. Increasing env-specific antibody titers in CSF were associated in one animal with strong intrathecal synthesis. SIVmac239-infected monkeys revealed high antibody titers of gag and env-specificity, in one animal accompanied by weak intrathecal synthesis of virus-specific antibodies. In all animals, the CD4/CD8 ratio in CSF decreased faster compared to blood. 相似文献
57.
为探讨八肽胆囊收缩素(CCk-8)和阿片肽相互作用的分子机理,利用抗体免疫沉淀技术研究了CCK-8与NDAP(k阿片受体激动剂)对大鼠脑(去皮层和小脑)和脊髓背柱组织Fos蛋白的影响。结果表明,0.1μmol/LCCK-8可显著刺激脑和脊髓组织中Fos蛋白增加(分别是对照组的3.8倍和3.6倍)。相同浓度的NDAP对Fos蛋白的生成亦有一定的诱导作用,分别是对照组的2.7倍和2.6倍。CCK-8和NDAP共同处理组织,Fos蛋白生成水平相似(脑)或高于(脊髓)CCK~-8单独诱导的水平。结果表明,CCK-8和NDAP均可直接诱导大鼠脑和脊髓组织c-fos的表达,它们对c-fos表达的相互作用在脑和脊髓中呈现不同的模式。 相似文献
58.
8-Hydroxydeoxyguanosine (8-OHdG) is now widely used as a sensitive marker of oxidative damage to DNA. When human granulocytes are stimulated with TPA, they release a large quantity of reactive oxygen species (superoxide, hydrogen peroxide) which might be expected to generate hydroxyl radicals (OH-) which in turn could produce 8-OHdG in the DNA. There had been considerable debate as to whether OH -is detectable in stimulated granulocytes; most workers now agree that none can be detected, unless exogenous iron is added. An earlier report had described that 8-OHdG (a marker of OH -) was increased in the DNA of TPA-stimulated, compared to control, granulocytes. We have repeated this experiment and have been unable to reproduce this Finding. We conclude that the amount of 8-OHdG produced in the DNA of TPA-stimulated human ganulocytes is indistinguishable from that seen in control (unstimulated) cells (less than one 8- OHdG/105 dG). 相似文献
59.
Kiwifruit β-galactosidase: Isolation and activity against specific fruit cell-wall polysaccharides 总被引:1,自引:0,他引:1
A -galactosidase (EC 3.2.1.23) capable of degrading a number of fruit cell-wall polysaccharides in vitro, was isolated from ripening kiwifruit (Actinidia deliciosa [A. Chev.] C.F. Liang et A.R. Ferguson cv. Hayward). The enzyme has a molecular weight of approximately 60 kDa by gel permeation and consists of several basic isoforms. Several polypeptides were enriched during purification, with 33-, 46- and 67-kDa bands being predominant after sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The optimum activity of the enzyme against p-nitrophenyl--d-galactopyranoside was at pH 3.2, but against a galactan purified from kiwifruit cell walls, it was at pH 4.9. The enzyme was specific for galactosyl residues in the -configuration, releasing galactose from a variety of kiwifruit cell-wall polysaccharide fractions including cell wall material, Na2CO3-soluble pectin, high-molecular-weight galactan, xyloglucan, and galactoglucomannan. A galactosylated glucuronomannan found throughout the kiwifruit plant was also a substrate for the enzyme. The results indicate that the enzyme attacks the non-reducing end of galactose side chains, cleaving single galactose residues which may be attached to the 2, 3, 4, or 6 position of the aglycone. Activity of the enzyme in-vitro was too low to account for the total loss of galactose from the cell walls during ripening. If the -galactosidase of this study is solely responsible for the removal of galactose from the cell wall during ripening then its in-vivo activity must be much greater than that observed in-vitro.Abbreviations CWM
cell wall material
- SDS-PAGE
sodium dodecyl sulphate-polyacrylamide gel electrophoresis
We thank Bronwyn Culling and Teresa Wegrzyn for assistance and acknowledge a contribution towards the cost of the research from the New Zealand Kiwifruit Marketing Board. 相似文献
60.
Van Lint Johan Van Damme Jo Billiau Alfons Merlevede Wilfried Vandenheede Jackie R. 《Molecular and cellular biochemistry》1993,127(1):171-177
The signal transduction initiated by the human cytokine interleukin-8 (IL-8), the main chemotactic cytokine for neutrophils, was investigated and found to encompass the stimulation of protein kinases. More specifically, IL-8 caused a transient, dose and time dependent activation of a Ser/Thr kinase activity towards myelin basic protein (MBP) and the MBP-derived peptide APRTPGGRR patterned after the specific concensus sequence in MBP for ERK enzymes. The activated MBP kinase was furthermore identified as an extracellular signal regulated kinase (ERK1) based on several criteria such as substrate specificity, molecular weight, activation-dependent mobility shift, and recognition by anti-ERK antibodies. For comparison, the chemotactic response of neutrophils to a stimulus of bacterial origin (fMet-Leu-Phe or fMLP) was also examined and found to involve the activation of a similar ERK enzyme. The present data clearly indicate that in terminally differentiated, non-proliferating human cells, the MBP kinase/ERK activity can serve other purposes than mitogenic signaling, and that processes such as chemotaxis, induced by bacterial peptides as well as by human cytokines like IL-8, involve the regulation of ERK enzyme.Abbreviations IL-8
interleukin-8
- fMLP
fMet-Leu-Phe
- MBP
myelin basic protein
- ERK
extracellular signal regulated kinase
- MAP2
microtubule-associated protein 2
- PK-A
cAMP dependent protein kinase
- PKI
protein kinase inhibitor
- PMSF
phenyl-methanesulfonyl fluoride
- PVDF
poly-vinylidene difluoride
- HBSF
Hank's buffered salt solution
- DAB
3,3-diaminobenzidine tetrahydrochloride
- PNPP
p-nitrophenyl-phosphate
- HSA
human serum albumin
- EGTA
[ethylenebis (oxyethylenenitrilo)]tetraacetic acid
- SDS-PAGE
sodium dodecyl sulfate polyacrylamide gel electrophoresis 相似文献