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51.
Molecular analysis of the envelope gene and long terminal repeat of Friend mink cell focus-inducing virus: implications for the functions of these sequences. 总被引:45,自引:33,他引:12
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We sequenced the envelope (env) gene and 3' long terminal repeat of a Friend mink cell focus-inducing virus (F-MCFV). We also sequenced the gp70 coding regions for two cDNA clones of another F-MCFV. The deduced amino acid sequence of the env gene products of both F-MCFVs were compared to the corresponding sequences of other MCFVs and of ecotropic viruses. The env polypeptides of the different viruses showed long stretches of homology in the carboxy-terminal half of gp70 and in p15env ("constant region"). The amino-terminal half of gp70 was very similar in all MCFVs, but showed extensive variations relative to the ecotropic viruses ("differential region"). This differential region in all MCFVs is of endogeneous origin. We show evidence that this region carries determinants for ecotropic or polytropic host range. No indication could be found that the env gene products determine the histological type of disease caused by particular MCFVs. When the long terminal repeats of F-MCFV and Friend murine leukemia virus were compared with those of other viruses causing either lymphatic leukemia or erythroleukemia, several nucleotides were localized which might determine the histological type of disease caused by these viruses. 相似文献
52.
53.
Hypoxia-induced alterations of norepinephrine vascular reactivity in isolated perfused cat lung 总被引:1,自引:0,他引:1
Past work in the isolated perfused cat lung has shown that acute hypoxia (H) changes the response to norepinephrine (NE) from vasoconstriction to vasodilation but has no effect on the response to serotonin (S). These results could be related to the increase in pulmonary arterial pressure or vascular resistance during the hypoxic pressor response or a direct effect of H. We addressed this question, in the same preparation, by comparing responses to NE under four conditions in each experimental animal (n = 12): 1) NE infused during normoxia; 2) NE infused after vascular resistance (Rpv) was increased with serotonin; 3) NE infused after Rpv was increased by H; 4) NE infused after lobar pressure was raised by an increase in flow (P/F). PO2 values during H were varied (27-56 Torr). S and H produced a 137 +/- 35 and 43 +/- 8% delta Rpv increase in lobar vascular resistance, respectively. P/F increased lobar pressure 91 +/- 10%. Only NE infusion during H demonstrated significant differences in lobar pressure and Rpv compared with control normoxic periods. There was no correlation between responses to NE during S, H, and P/F and degree to which each stimulus increased Rpv or lobar pressure (r = 0.003, 0.28, 0.24). A significant relationship between response to NE during H vs. PO2 during H was observed (r = 0.78; P less than 0.001). In a subset of animals, we repeated the infusion of NE during H and P/F post-beta-blockade. The decrease in vascular response to NE during H and the correlation of PO2 with NE response were abolished (n = 7).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
54.
Dr. Hans-Joachim Gabius Katalin Vehmeyer Reinhild Engelhardt Gerd A. Nagel Friedrich Cramer 《Cell and tissue research》1986,246(3):515-521
Summary A tumor model system of clones of myeloproliferative sarcoma virus (MPV)-transformed rat fibroblasts (NRK) with different growth properties and metastatic potential was studied. The relationship between metastatic behavior and composition of carbohydrate-binding proteins (lectins) was analyzed by affinity chromatography. The metastatic variant differs qualitatively from its parental clone in the presence of galactoside-binding proteins at apparent molecular weights of 80 kDa, 70 kDa, 22 kDa, 18 kDa and 16 kDa and of a fucose-binding protein at apparent molecular weight of 42 kDa. The -glucosyl-binding proteins at apparent molecular weights of 67 kDa and 53 kDa and a galactoside-binding protein of apparent molecular weight of 34 kDa, however, are not detectable in the metastatic variant in comparison to its parental clone. In this respect the parental clone shows closer resemblance to the clone 5–8#1 with different growth properties and low metastatic potential than to its own metastatic variant. Furthermore, only the parental clone has a melibiose- and a mannan-binding protein of an apparent molecular weight of 64 kDa and 14 kDa, respectively. Rosette formation as model system for intercellular interaction reveals differences in the inhibition pattern with sugar between the two clones 5–8#1 and 5–20#20, whereas the metastatic variant 5–20#20 (s) exhibits drastically reduced capability to form rosettes. Initial experiments demonstrate the feasibility of drug targeting to transformed fibroblasts via carbohydrate-binding proteins. 相似文献
55.
Alexander M. Eggermont Willem Weimar Bhupendra Tank Amelie M. Dekkers-Bijma Richard L. Marquet Johannes S. Lameris Dick L. Westbroek Johannes Jeekel 《Cancer immunology, immunotherapy : CII》1986,21(1):81-84
Summary A total of 20 patients with advanced colorectal cancer received recombinant leukocyte interferon-A (rIFNA) either chronically (group I: twice a week up to 20×106 IU/m2 i.m.) or cyclically (group II: 1–4 periods of 8 consecutive days up to 20×106 IU/m2 i.m. daily at 20-days intervals) over a period of 12 weeks. There was 1 partial response, 1 mixed response and 1 patient with stable disease, whilst 17 patients had progressive disease. Median survival was 15.5 months. Survival was significantly shorter when the extent of hepatic disease was >25% (P=0.05), extrahepatic disease was extensive (P<0.005), alkaline phosphatase level was >2× normal (P<0.02), or performance status was <100% (P<0.001). Toxicity consisting mainly of fever, fatigue, anorexia and weight loss was serious in group I and minimal in group II. Administration of rIFNA led to a short lived augmentation of natural killer (NK) cell activity. In the cyclically treated group this was a recurrent phenomenon whereas a marked lasting depression of NK cell activity was seen in chronically treated patients. Interferon- production capacity was significantly stimulated during rIFNA therapy. The differences in toxicity and immunostimulatory effects between the two schedules may be of importance in the design of further studies.This trial was supported in part by Hoffmann-La Roche, Basle 相似文献
56.
M Solti P Dévay I Kiss J Londesborough P Friedrich 《Biochemical and biophysical research communications》1983,111(2):652-658
Like adult heads and whole flies, larval brains of wild type Drosophila melanogaster contain two major soluble cyclic nucleotide phosphodiesterases, forms I and II. Larval brains of the learning-defective mutant strain, dunceM11, contain only the form I enzyme. In both wild type and dunce strains the form I enzyme is activated by Ca2+/calmodulin. A time-dependent loss of this Ca2+ activation was observed. 相似文献
57.
Abstract: Primary cultures were prepared from newborn rat brain. After 16-18 days, they consisted mainly of mature and immature astrocytes and oligodendrocytes, as judged by immunohistochemistry. To study the metabolism of ethanolamine glycerophospholipids, the cells were incubated with 1-[1-3 H]alkyl- sn -glycero-3-phosphoethanolamine (1-alkyl-GPE), for 1–20 h. Five main products were formed: 1-alkyl-2-acyl-GPE; 1-alkyl-2-acyksn-glycero-3-phosphocholine (1-alkyl-2-acyl-GPC); 1-alkenyl-2-acyl-GPE (ethanolamine plasmalogen); 1-alkenyl-2-acyl-GPC (choline plasmalogen); and 1-alkyl-glycerol. Acylation of the substrate was the main reaction during the first 3 h of incubation, whereas desaturation to plasmaiogen reached a maximum after 12 h. Greater amounts of radioactivity were observed in the phosphatidylcholine fraction after longer incubation times. Only small amounts of choline plasmalogen were observed. The phosphatidylethanolamine fraction consisted of 26.5% diacyl-, 27.5% alkyl-acyl-, and 46.0% alkenyl-acyl- compounds, whereas the corresponding data for the phosphatidylcholine fraction were 78.5, 16.4, and 5.1%, respectively, after 20 h of incubation. Hydrolysis of the substrate to 1-alkyl-glycerol was a minor reaction. 相似文献
58.
59.
60.
Mathias Sprinzl Karl-Heinz Scheit Hans Sternbach Friedrich von der Haar Friedrich Cramer 《Biochemical and biophysical research communications》1973,51(4):881-887
2′-Deoxyadenosine and 3′-deoxyadenosine (cordycepin) can be incorporated into the 3′-terminal position of tRNAPhe by tRNA nucleotidyl transferase. tRNAPhe-C-C-2′dA and tRNAPhe-C-C-3′dA, missing the cis-diol group at the 3′-terminal end are resistant to periodate oxidation and are not able to form borate complexes. In aminoacylation experiments only the tRNAPhe-C-C-3′dA proved to be chargeable. 相似文献