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51.
Synthesis and degradation of collagens in skin of healthy and protein-malnourished rats in vivo, studied by 18O2 labelling. 总被引:1,自引:0,他引:1
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J A Molnar N M Alpert D A Wagner S Miyatani J F Burke V R Young 《The Biochemical journal》1988,250(1):71-76
To explore the effects of growth retardation, caused by restricted protein intake, on collagen turnover in the whole skin, Sprague-Dawley rats (n = 20) were labelled with 18O2 and fed on either an adequate (18%) or a low (3%) lactalbumin diet. Skin biopsies were obtained at intervals during the following 6 months. Independent groups of animals (n = 186) were used to determine the size of the 0.5 M-acetic acid-soluble and -insoluble collagen pools in the entire skin of healthy and malnourished rats. Collagen was estimated by measurement of hydroxyproline. Soluble-collagen synthesis rates were equivalent to 99 +/- 8 mumol of hydroxyproline/day in healthy animals and 11 +/- 2 mumol/day in malnourished rats. Insoluble-collagen synthesis rates were 32 and 5 mumol of hydroxyproline/day in the healthy and protein-depleted rats respectively. The degradation of soluble collagen amounted to 37 +/- 8 and 6 +/- 2 mumol of hydroxyproline/day in the healthy and malnourished groups respectively. Efflux of collagen from the soluble collagen, defined as the sum of the rate of soluble collagen that is degraded plus that which matures into insoluble collagen, was 70 +/- 8 and 11 +/- 2 mumol of hydroxyproline/day in the healthy and malnourished groups respectively. Insoluble collagen was not degraded in either group. The fraction of soluble collagen leaving the pool that was converted into insoluble collagen was 0.46 in both diet groups. It is concluded that the turnover of soluble collagen is markedly decreased with malnutrition, but degradation and conversion into insoluble collagen account for the same proportions of efflux from the soluble-collagen pool as in rapidly growing rats. 相似文献
52.
G. Wiedemann R. Pabst T. Wagner F. Trepel 《Virchows Archiv. B, Cell pathology including molecular pathology》1988,56(1):407-412
Labelling index after one or repeated intravenous injections of 3H-thymidine was measured for various subpopulations of lymphatic
cells in different canine lymphoid compartments and correlated with cell morphology. High doses of tritiated thymidine were
injected and exposure times of up to 211 days were used. The labelling indices of lymphoid blasts were comparable in all tissues
investigated. Labelling index varied from 100% in immunoblasts to 4% in small-sized lymphocytes. Approximately 80% of immunoblasts
were labelled 1 h after 3H-thymidine application and 100% labelling was obtained after 12 h repetitive 3H-thymidine labelling.
In contrast with mediumsized and large lymphocytes, immunoblasts seem to be rapidly proliferating cells in the dog with almost
no Go cells.
Supported by the Deutsche Forschungsgemeinschaft DFG Grant SFB 112 相似文献
53.
54.
This report describes the development and use of functional immunoradiometric assays that distinguish the activity of beta-migrating endothelial-type plasminogen activator inhibitor (PAI-1) from that of placental-type plasminogen activator inhibitor (PAI-2). These assays are based upon the binding of PAI-1 and PAI-2 to immobilized single-chain tissue-type plasminogen activator (tPA) and to immobilized urokinase (UK), respectively. The extent of binding of each PAI is quantified by incubating the PAI-PA complex first with rabbit antiserum specific for the individual PAI and then with 125I-labeled goat antirabbit IgG. In control experiments, the assays were shown to be sensitive, dose-dependent over a wide range, and specific for each PAI. These assays were employed to establish the PAI profile of a variety of human cells. Neither PAI-1 nor PAI-2 could be detected in Bowes melanoma cells or in a renal adenocarcinoma cell line (ACHN), while the histiocytic lymphoma cell (U-937) produced only PAI-2. Five cell lines, including two that were previously shown to contain one or the other PAI (e.g., umbilical vein endothelial cells and a fibrosarcoma cell line, HT-1080) in fact contained both PAIs. The cells containing both PAIs were studied in more detail. In each case, SDS treatment of CM was shown to enhance PAI-1 activity (by converting the latent form of this inhibitor into its active form) and to destroy PAI-2 activity. Various compounds including interleukin 1, dexamethasone, and phorbol myristate acetate were found to selectively influence the cellular production of one PAI without concomitantly affecting the production of the other, suggesting that the synthesis of these inhibitors is not coordinately regulated. 相似文献
55.
V Bencko V Wagner M Wagnerová J Bátora 《Journal of hygiene, epidemiology, microbiology, and immunology》1988,32(2):137-146
A group of 47 male adults working in a thermal power plant burning coal containing 900 to 1,500 g of arsenic per ton dry weight was examined on the blood serum immunoglobulins IgG, IgA and IgM content and levels of acute reactants alpha-1-antitrypsin (A1AT), alpha-2-macroglobulin (A2M), transferrin (TRF), orosomucoid (ORO) ceruloplasmin (CPL), and lysozyme (LYS). Investigations in the control group comprising 27 workers from another power plant in the same district where the coal content of arsenic was more than 10 times lower were analogous. The inter-group differences in means were evaluated by t-test, differences in the association of values by F-test, and the correlations with age and the length of exposure were assessed using the regression analysis method. The differences in mean IgG, IgA, IgM, LYS and A2M levels between the exposed and control groups of workers were insignificant or of borderline significance only. In contrast, differences in TRF, ORO and particularly CPL levels were statistically highly significant, in all instances P less than 0.001. In the control group, persons with abnormal values in at least two immunobiochemical tests used accounted for 3.7%, in the group of the exposed for 51% (P less than 0.002). All these findings, especially the rise in CPL concentration levels in the exposed group are discussed on the background of the rise in cancer mortality rates found previously in this group of power plant workers. 相似文献
56.
57.
Conformation of [Cd7]-metallothionein-2 from rat liver in aqueous solution determined by nuclear magnetic resonance spectroscopy 总被引:5,自引:0,他引:5
P Schultze E W?rg?tter W Braun G Wagner M Vasák J H K?gi K Wüthrich 《Journal of molecular biology》1988,203(1):251-268
The three-dimensional structure of [Cd7]-metallothionein-2 from rat liver was determined in aqueous solution, using nuclear magnetic resonance spectrometry and distance geometry calculations. The experimental data provided proton-proton distance constraints from measurements of nuclear Overhauser effects, constraints on the geometry of the metal-cysteine clusters determined by heteronuclear correlation spectroscopy, and dihedral angle constraints derived from both coupling constants and nuclear Overhauser effects. The structure calculations were performed with the program DISMAN. As in previous studies with rabbit liver metallothionein-2a, the structure calculations were performed separately for the alpha and beta-domains containing the 4 and 3-metal clusters, respectively, since no interdomain constraints were found. For both domains, the global polypeptide fold, the location of polypeptide secondary structure elements, the architecture of the metal-sulfur cluster and the local chirality of the metal co-ordination are very similar to the solution structure of rabbit metallothionein-2a, but show considerable difference relative to the crystal structure of rat metallothionein-2. 相似文献
58.
Lawrence E. Shapiro Neil Wagner 《In vitro cellular & developmental biology. Plant》1988,24(4):299-303
Summary Serum-free tissue culture medium consisting of a 1∶1 mixture of Dulbecco's modified Eagle's medium (DMEM) and Ham's F12 medium
is herein shown to support growth of Reuber H-35 cells over several days in culture. Cells were initially plated in serum
containing DMEM medium for 3 h. After cell attachment, serum is removed and replaced with a serum-free 1∶1 mixture of these
two commercially available tissue culture media. The doubling time of cell growth in this unsupplemented serum-free medium
was 46 h in lightly plated cultures over the first 5 d. The presence of transferrin (5 μg/ml) and insulin (3.3 nM) results in a cell doubling time of 17 h, which equaled the growth rate in medium containing 10% fetal bovine serum. In the
absence of transferrin, growth rates in serum-free medium were correlated with the cell density of cultures. Conditioned medium
from dense, serum-free cultures has growth-stimulating activity in recipient lightly plated cultures. This simple, serum-free
culture medium will facilitate studies on the growth regulation of H-35 rat hepatoma cells.
This work was funded by a feasibility grant from the American Diabetes Association, as well as by the National Institutes
of Health grants CA 24604-09 and CA 16463-14. 相似文献
59.
60.
Unstable amplification of two extrachromosomal elements in alpha-difluoromethylornithine-resistant Leishmania donovani.
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We describe the first example of unstable gene amplification consisting of linear extrachromosomal DNAs in drug-resistant eukaryotic cells. alpha-Difluoromethylornithine (DFMO)-resistant Leishmania donovani with an amplified ornithine decarboxylase (ODC) gene copy number contained two new extrachromosomal DNAs, both present in 10 to 20 copies. One of these was a 140-kb linear DNA (ODC140-L) on which all of the amplified copies of the odc gene were located. The second was a 70-kb circular DNA (ODC70-C) containing an inverted repeat but lacking the odc gene. Both ODC140-L and ODC70-C were derived from a preexisting wild-type chromosome, probably by a conservative amplification mechanism. Both elements were unstable in the absence of DFMO, and their disappearance coincided with a decrease in ODC activity and an increase in DFMO growth sensitivity. These results suggest the possibility that ODC70-C may play a role in DFMO resistance. These data expand the diversity of known amplification mechanisms in eukaryotes to include the simultaneous unstable amplification of both linear and circular DNAs. Further characterization of these molecules will provide insights into the molecular mechanisms underlying gene amplification, including the ability of linear amplified DNAs to acquire telomeres and the determinants of chromosomal stability. 相似文献