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61.
Plasma free and sulfate conjugated catecholamine levels during acute physiological stimulation in man 总被引:1,自引:0,他引:1
The responses of plasma free and sulfate-conjugated catecholamines to acute physiological stimulation was examined in normal male subjects. Catecholamines were measured with a sensitive radioenzymatic assay incorporating simultaneous hydrolysis of sulfate conjugates and O-methylation of free norepinephrine and epinephrine. Following 20 minutes recumbency after venepuncture 30 +/- 3% of norepinephrine and 16 +/- 5% of epinephrine was in thr free form. Free catecholamines generally increased during standing, cold immersion and isometric handgrip, but sulfates did not change. Bicycle ergometry markedly increased free catecholamines which rapidly returned to basal levels at the end of exercise. In contrast, sulfated norepinephrine decreased substantially with exercise in all subjects but returned to basal levels 3 minutes after stopping exercise. Epinephrine sulfate varied considerably between subjects but showed a similar, although smaller, fall with exercise. Thus, during physiological stimulation, which caused increases in free norepinephrine and epinephrine levels in plasma, the only consistent change in sulfated catecholamines was a marked fall in norepinephrine sulfate after bicycle exercise. This may indicate saturation of sulfotransferase activity, substrate inhibition or impaired tissue conjugation. 相似文献
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Heteroduplex analysis of the RNA isolated from purified virions of clone 3 Moloney murine sarcoma virus (M-MSV) hybridized to cDNA's from Moloney murine leukemia virus (M-MLV) and clone 124 M-MSV shows that the main physical component of clone 3 RNA is missing all or most of the 1.5-kilobase (kb) clone 124 M-MSV specific sequence denoted beta s (S. Hu et al. Cell 10:469--477, 1977). This sequence is either deleted in clone 3 RNA or substituted by a very short (0.3-kilobase) sequence. In other respects, clone 3 and clone 124 RNAs show the same heteroduplex structure relative to M-MLV. Since beta s is believed to contain the src gene(s) of clone 124 RNA, this result leaves as an unresolved question the nature of the src gene(s) of the clone 3 M-MSV RNA complex. 相似文献
64.
B A Davidson 《Plastic and reconstructive surgery》1979,63(3):350-354
A technique is described for excising the excess skin in gynecomastia operations, using a concentric "circle" design to remove a calculated amount in the vertical in the horizontal directions. The sole residual scar is a circular one around the periphery of the areola. 相似文献
65.
Summary Lateral roots ofVicia faba were treated with a solution of 5-aminouracil (3.93 × 10–3 M). They were either treated for 6 hours and allowed to recover for up to 10 hours, or were treated continuously for up to 24 hours. Mitotic index decreased as the duration of treatment increased,e.g., it was < 0.5 after 6 hours treatment and 4 hours recovery and 0.23 after 12 hours continuous treatment. During this period of low mitotic activity nuclei and cells increased in size: mean nuclear volume, for example, was 1505±651 m3 8 hours after the end of a 6 hours treatment. In roots treated continuously, nuclear volume increased from 559±204 m3 at 0 hour to 1272±636 m3 at 12 hours. In the first 3 hours it was the larger nuclei that grew,i.e., nuclei that would have proceeded into mitosis if they had not been blocked by 5-AU. But between 3 and 12 hours of continuous exposure to 5-AU all nuclei increased in volume. Cells, on the other hand, showed no response during the first 6 hours of treatment; their areas did not increase till 6–12 hours had elapsed. It appears that in cells blocked by 5-AU growth continues for about 12 hours. Initially, nuclei grow disproportionately large, suggesting that synthesis of nuclear components is favoured at the expense of cytoplasmic constituents, at least during the first 6 hours of treatment; there is an internal imbalance between nuclear and cell growth and a temporary change in the nuclear cytoplasmic ratio. When cells recover from the 5-AU block and enter mitosis their prophase nuclei are also much larger than those of untreated cells. The response to 5-AU is discussed in terms of internal restrictions on cell growth, due to the presence of cell walls, and the heterogeneity in nuclear volumes. 相似文献
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Mark A. Yorek Joyce A. Dunlap Mark R. Stefani Eric P. Davidson 《Journal of neurochemistry》1992,58(5):1626-1636
It has been proposed that abnormal myo-inositol metabolism may be a factor in the development of diabetic complications. Studies with animal models of diabetes and cultured cells have suggested that hyperglycemia by an unknown mechanism may alter myo-inositol metabolism and content. Recently, we have shown that L-fucose, a 6-deoxy sugar whose content has been reported to be increased in diabetes, is a potent inhibitor of myo-inositol transport. To examine the effect of L-fucose on myo-inositol metabolism, neuroblastoma cells were cultured in medium supplemented with L-fucose. L-Fucose is a competitive inhibitor of Na(+)-dependent, high-affinity myo-inositol transport. The Ki for inhibition of myo-inositol transport by L-fucose is about 3 mM. L-Fucose is taken up and accumulates in neuroblastoma cells. The uptake of L-fucose is inhibited by Na+ depletion, D-glucose, glucose analogues, phloridzin, and cytochalasin B. In contrast, neither myo-inositol nor L-glucose inhibits L-fucose uptake. Chronic exposure of neuroblastoma cells to 1-30 mM L-fucose causes a decrease in myo-inositol accumulation and incorporation into inositol phospholipids, intracellular free myo-inositol content, and phosphatidylinositol levels. Na+,K(+)-ATPase transport activity is decreased by about 15% by acute or chronic exposure of neuroblastoma cells to L-fucose. Similar defects occur when neuroblastoma cells are exposed chronically to 30 mM glucose. Cell myo-inositol metabolism and Na+/K(+)-pump activity are maintained when 250 microM myo-inositol is added to the L-fucose-supplemented medium. Unlike the effect of chronic exposure of neuroblastoma cells to medium containing 30 mM glucose, the resting membrane potential of neuroblastoma cells is not altered by chronic exposure of the cells to 30 mM L-fucose. The effect of L-fucose on cultured neuroblastoma cell properties occurs at concentrations of L-fucose which may exist in the diabetic milieu. These data suggest that increased concentrations of L-fucose may have a role in myo-inositol-related defects in mammalian cells. 相似文献
69.
Diseases and parasites of red foxes, gray foxes, and coyotes from commercial sources selling to fox-chasing enclosures. 总被引:3,自引:0,他引:3
W R Davidson M J Appel G L Doster O E Baker J F Brown 《Journal of wildlife diseases》1992,28(4):581-589
Fifty-six red foxes (Vulpes vulpes), 18 gray foxes (Urocyon cinereoargenteus), and 13 coyotes (Canis latrans) obtained by the South Carolina Wildlife and Marine Resources Department during an investigation of suspected illegal wildlife translocation were examined for diseases and parasites. Red foxes and coyotes were confiscated from an animal dealer based in Ohio (USA), and gray foxes were purchased from an animal dealer in Indiana (USA). Emphasis was placed on detection of pathogens representing potential health risks to native wildlife, domestic animals, or humans. All animals were negative for rabies; however, 15 gray foxes were incubating canine distemper at necropsy. Serologic tests disclosed antibodies to canine parvovirus, canine distemper virus, canine adenovirus, canine coronavirus, canine herpesvirus, and canine parainfluenza virus in one or more host species. Twenty-three species of parasites (two protozoans, three trematodes, four cestodes, eleven nematodes, and three arthropods) were found, including species with substantial pathogenic capabilities. Echinococcus multilocularis, a recognized human pathogen not enzootic in the southeastern United States, was found in red foxes. Based on this information, we conclude that the increasingly common practice of wild canid translocation for stocking fox-chasing enclosures poses potential health risks to indigenous wildlife, domestic animals, and humans and, therefore, is biologically hazardous. 相似文献
70.
Oligosaccharide structures present on asparagine-289 of recombinant human plasminogen expressed in a Chinese hamster ovary cell line 总被引:2,自引:0,他引:2
The oligosaccharide structures linked to Asn289 of a recombinant (r) variant (R561S) human plasminogen (HPg) expressed in Chinese hamster ovary (CHO) cells, after transfection of these cells with a plasmid containing the cDNA coding for the variant HPg, have been determined. Employing high-performance anion-exchange liquid chromatography mapping of the oligosaccharide units cleaved from the protein by glycopeptidase F, compared with elution positions of standard oligosaccharides, coupled with monosaccharide compositional determinations and analyses of sequential exoglycosidase digestions and specific lectin binding, we find that considerable microheterogeneity in oligosaccharide structure exists at this sole potential N-linked glycosylation site on HPg. A variety of high-mannose structures, as well as bi-, tri-, and tetraantennary complex-type carbohydrate, has been found, in relative amounts of 1-25% of the total oligosaccharides. The complex-type structures contain variable amounts of sialic acid (Sia), ranging from 0 to 5 mol/mol of oligosaccharide in the different glycan structures. Neither hybrid-type molecules, N-acetylglucosamine bisecting oligosaccharides, nor N-acetyllactosaminyl-repeat structures were found to be present in the complex-type carbohydrate pool in observable amounts. Of interest, a significant portion of the Sia exists an outer arm structures in an (alpha 2,6) linkage to the penultimate galactose, a novel finding in CHO cell-directed glycosylation.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献