FIBRIN STIMULATION OF ENDOTHELIAL CELL (EC) PRODUCTION OF PGI AND TISSUE PLASMINOGEN ACTIVATOR (t-PA)

1987 ◽  
Author(s):  
L K Kaplan ◽  
T Mather ◽  
L DeMarco ◽  
S Solomon
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
Umbilical Vein ◽  
Cytochalasin D ◽  
Time Dependent ◽  
Time Intervals ◽  
Tissue Plasminogen ◽  
Protein And Rna Synthesis ◽  
Maximal Production ◽  
Stimulation Of

Many substances are known to stimulate EC production of PGI2 and t-PA. Additionally, it has been reported that fibrin can Be formed on the EC surface. In this study, the possibility that fibrin generated on the surface of cells can stimulate production of PGI2 and t-PA was examined. Human umbilical vein ECs were incubated for various time intervals with citrated human plasma clotted on the cells by the addition of CaCl2 . Control dishes contained plasma without Ca++ or serum. Time-dependent generation of PGI2 and t-PA was seen over 22-24 hours. Maximal production of PGI2 occurred when fibrin on the cells was formed from 10 to 50% plasma, with serum comprising the remainder of the incubation volume, while maximal t-PA production occurred with clots formed from 100% plasma. Fibrin I formed by addition of batroboxin to citrated plasma stimulated less synthesis of t-PA than did fibrin formed by thrombin action, and it did not stimulate PGI2 production. Thrombin clots were significantly more adherent to the cells than were batroboxin clots. PG^ synthesis induced by fibrin was fully inhibited by indomethacin, approximately 50% inhibited by actinomycin D and cycloheximide, and 20% inhibited by trifluoperazine, but was unaffected by cytochalasin D and vinblastine. Stimulation of t-PA synthesis by fibrin was unaffected by indomethacin, completely inhibited by actinomycin D and cycloheximide, and 60%, 80% and 40% blocked by cytochalasin D, vinblastine, and trifluoperazine, respectively. Thus, thrombin-induced fibrin clots stimulated PGI2 synthesis, and both thrombin and batroboxin clots stimulated t-PA synthesis. Protein and RNA synthesis were essential to stimulation of t-PA synthesis but inhibition of these processes only partially inhibited stimulation of PGI2 synthesis. Integrity of the cytoskeleton was necessary for full stimulation of t-PA synthesis, but not for stimulation of PGI2 synthesis. Thus the mechanisms of stimulation of these two cellular products were different. Increased PGI2 production could serve to limit further fibrin formation by preventing platelets from contributing to the coagulation process and increased t-PA could stimulate lysis of existing fibrin.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

scholarly journals Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Glucose Utilization ◽  
Actinomycin D ◽  
Hormone Synthesis ◽  
Pituitary Glands ◽  
Hormone Biosynthesis ◽  
Stimulation Of

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

Stimulation of protein and RNA synthesis by methylmercury chloride in the liver of intact and adrenalectomized rats

1981 ◽  
Vol 47 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Saburo Omata ◽  
Hidemi Tsubaki ◽  
Kenji Sakimura ◽  
Mitsuru Sato ◽  
Ryuji Yoshimura ◽  
...  
Keyword(s):  
Rna Synthesis ◽  
Methylmercury Chloride ◽  
Protein And Rna Synthesis ◽  
Adrenalectomized Rats ◽  
Stimulation Of

STUDIES ON THE MECHANISM OF ACTION OF ANGIOTENSIN ON FLUID TRANSPORT BY THE MUCOSA OF RAT DISTAL COLON

1972 ◽  
Vol 54 (3) ◽  
pp. 483-492 ◽  
Author(s):  
N. T. DAVIES ◽  
K. A. MUNDAY ◽  
B. J. PARSONS
Keyword(s):  
Protein Synthesis ◽  
Cyclic Amp ◽  
Rna Synthesis ◽  
Fluid Transport ◽  
Actinomycin D ◽  
Distal Colon ◽  
Rat Colon ◽  
Colon Mucosa ◽  
Rat Distal Colon ◽  
Stimulation Of

SUMMARY A study was made of the effects of cyclic AMP, theophylline, cycloheximide, puromycin and actinomycin D on the stimulation by angiotensin of fluid transport by sacs of rat colon mucosa. Cyclic AMP and theophylline, added together or separately, had no effect on fluid transport by colon sacs, suggesting that the stimulation of fluid transport after the application of angiotensin is not mediated through cyclic AMP. Cycloheximide and puromycin (used at concentrations which block colon protein synthesis by 50–90%) had no effect on fluid transport by control colon sacs, but completely blocked the stimulatory response of the colon to angiotensin. In contrast, actinomycin D (at a concentration which significantly inhibits RNA synthesis) did not affect fluid transport in control or angiotensin-stimulated colon sacs. The results are discussed in relation to the possibility that protein synthesis, at the stage of translation, is involved in the action of angiotensin on fluid transport by the colon.

GIBBERELLIN, AS A REGULATOR OF PROTEIN AND RIBONUCLEIC ACID SYNTHESIS DURING SENESCENCE IN LEAF CELLS OF TARAXACUM OFFICINALE

1966 ◽  
Vol 44 (6) ◽  
pp. 739-745 ◽  
Author(s):  
R. A. Fletcher ◽  
Daphne J. Osborne
Keyword(s):  
Leaf Senescence ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Acid Synthesis ◽  
Taraxacum Officinale ◽  
Leaf Discs ◽  
Protein And Rna Synthesis ◽  
Chlorophyll Protein ◽  
Gibberellin Treatment

The addition of gibberellin A3 (GA) to leaf discs of Taraxacum officinale Weber retards their senescence and delays the decline in the levels of chlorophyll, protein, and RNA. Incorporation of 14C leucine and 14C adenine into protein and RNA respectively was increased by GA. This enhancement of protein and RNA synthesis did not occur if the discs were supplied with actinomycin D before treatment with gibberellin. If, however, actinomycin D was added after the gibberellin treatment then the stimulatory effect of the hormone was maintained. These results suggest that the retarding action of gibberellins on leaf senescence could be mediated through a regulation of RNA synthesis that is DNA dependent.

scholarly journals STIMULATION BY INSULIN OF RNA SYNTHESIS IN CHICK FIBROBLASTS

1974 ◽  
Vol 60 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Joel B. Baseman ◽  
Domenic Paolini ◽  
Harold Amos
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Polymerase Activity ◽  
Serum Free Medium ◽  
5S Rna ◽  
Fresh Serum ◽  
Protein And Rna Synthesis ◽  
Rna Polymerase Activity ◽  
Kinetics Of ◽  
Stimulation Of

After the addition of insulin to monolayers of chick fibroblasts previously incubated in serum-free medium, the rates of protein and RNA synthesis increase continuously during the first 8–10 h. Little stimulation of DNA synthesis or mitosis results with the addition of insulin alone in contrast to the addition of fresh serum which stimulates both markedly. The stimulation in RNA synthesis does not result from expansion of the nucleotide pool but is correlated with increases in RNA polymerase activity. All major classes of RNA are stimulated; processing of preribosomal RNA to 28S and 18S and the association of this mature RNA with ribosomes appear to occur normally. The kinetics of stimulation of 5S RNA differ from those of the synthesis of 4S and of ribosomal RNA. Insulin and serum appear to affect the synthesis or stability of certain transcripts differentially.

scholarly journals Improvement in Thrombolytic Therapy Administration in Acute Stroke with Feedback

2012 ◽  
Vol 39 (6) ◽  
pp. 789-792 ◽  
Author(s):  
Esseddeeg Ghrooda ◽  
Susan Alcock ◽  
Alan C. Jackson
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Clinical Performance ◽  
Recombinant Tissue Plasminogen Activator ◽  
Health Sciences ◽  
Time Dependent ◽  
Time Intervals ◽  
Retrospective Audit ◽  
Time Period ◽  
Tissue Plasminogen

Background:The benefits of intravenous recombinant tissue plasminogen activator (rt-PA) in acute ischemic stroke is time dependent. Guidelines recommend a door-to-needle (DTN) time of less than 60 minutes.Methods:A retrospective audit of 730 stroke charts from 2008 - 2011 was conducted at Health Sciences Centre. 158 patients treated with IV rt-PA were identified. The time intervals between Emergency Department (ED) arrival, administration of rt-PA and uninfused brain computed axial tomographic scan (CT) were recorded. From this, CT to needle times were calculated. During November 2010 to January 2011 feedback was given to neurologists, ED physicians, ED nurses, and CT technologists. This raised awareness and emphasized the importance of this time driven protocol.Results:The median DTN times for 2008, 2009, and 2010 were 69, 71 and 76 minutes respectively. The median CT-to-needle time for this time period was 47 minutes. In 2011 (n =58) the median DTN time was 49 minutes and the median CT-to-needle was 18 minutes, which were marked improvements (p<0.00005 and p<0.005, respectively). In 2008-2010 only 31% of treated patients (n=100) received rt-PA within 60 minutes, whereas in 2011 this increased to 64%.Conclusions:Dramatic improvements in DTN times and in the percentage of patients receiving rt-PA treatment within 60 minutes were observed in 2011 after feedback was provided regarding the suboptimal performance. Prior to receiving feedback, DTN times were similar to national median DTN times. All centres administering rt-PA for acute ischemic stroke should monitor their clinical performance and give feedback on a regular basis.

scholarly journals SYNTHESIS OF MESSENGER-LIKE RIBONUCLEIC ACID AND PROTEIN DURING MEIOSIS IN ISOLATED CELLS OF TRILLIUM ERECTUM

1963 ◽  
Vol 19 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Yasuo Hotta ◽  
Herbert Stern
Keyword(s):  
Messenger Rna ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Morphological Changes ◽  
Reaction Rates ◽  
Meiotic Stage ◽  
Isolated Cells ◽  
Rna Analysis ◽  
Protein And Rna Synthesis

The synthesis of RNA and protein by cultures of isolated microsporocytes has been demonstrated. The variation in capacities of such cultures to perform syntheses is a function of meiotic stage and parallels the pattern of changes observed for microsporocytes in situ. A principal feature of this pattern is the induction of syntheses during pachytene and diplotene, stages at which the chromosomes are partly contracted. By use of Actinomycin D, chloramphenicol, pulse-labeling with P32-phosphate, and nucleotide analyses of RNA digests, part of the RNA synthesized has been shown to correspond to messenger RNA. Analysis of reaction rates and the overlappings of protein and RNA synthesis indicates that the spread of cytological events in Trillium is not purely a function of the low temperature at which it occurs but, presumably, arises from a complement of regulatory devices which govern the periodic onset of reactions within the cells. The main conclusion drawn from the whole of these studies is that the sequence of morphological changes associated with chromosome contraction and movement during meiosis is accompanied by a set of gene transcriptions. Although comparatively few genes are presumed to be active during meiosis, the action of such genes may be essential to a translation of some of the information embodying the meiotic sequence which has been stored in the genome in the course of evolution.

scholarly journals SYNTHESIS OF PLASMA MEMBRANE-ASSOCIATED AND SECRETORY IMMUNOGLOBULIN IN DIPLOID LYMPHOCYTES

1972 ◽  
Vol 135 (1) ◽  
pp. 136-149 ◽  
Author(s):  
Richard A. Lerner ◽  
Patricia J. McConahey ◽  
Inga Jansen ◽  
Frank J. Dixon
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Plasma Membrane ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
G1 Phase ◽  
Synchronized Cells ◽  
Disappearance Time ◽  
Protein And Rna Synthesis ◽  
Secretory Immunoglobulin

The half disappearance time for detectable plasma membrane-associated and cytoplasmic immunoglobulin after treatment of continuously growing diploid lymphocytes with inhibitors of protein and RNA synthesis was studied. Also, the amount of plasma membrane-associated and cytoplasmic immunoglobulin of synchronized cells in the G1 phase of the cell cycle has been studied. Plasma membrane-associated immunoglobulin has a half disappearance time of 45 min after inhibition of protein synthesis. By contrast, after treatment of cells with actinomycin D for 24 hr, plasma membrane-associated immunoglobulin remains relatively unchanged whereas cytoplasmic immunoglobulin decreased by almost 90%. In the G1 phase of the cell cycle, plasma membrane-associated immunoglobulin and cytoplasmic immunoglobulin were 70 and 10%, respectively, of that in logarithmically growing cells, and the half disappearance of M-Ig after treatment of cells with puromycin was again 45 min. In toto, these results suggest that perhaps secreted and plasma membrane-associated immunoglobulin may be separately controlled by the cells.

scholarly journals The synthesis of ribonucleic acid in immature rat uterus responding to oestradiol-17β

1971 ◽  
Vol 125 (2) ◽  
pp. 605-614 ◽  
Author(s):  
J. T. Knowler ◽  
R. M. S. Smellie
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
Soluble Fraction ◽  
Rat Uterus ◽  
Immature Rat ◽  
Radioactive Precursor ◽  
Major Increase ◽  
Very High ◽  
Time Of Administration ◽  
Stimulation Of

Stimulation of incorporation of labelled precursors into the RNA of immature rat uterus is an early result of oestradiol-17β action. However, the extent of the increased incorporation varies with the mode of administration of the labelled precursors and with the weight of the rat. At the age and weight range normally used response is maximal at ten times control incorporation, 4h after the administration of 0.3μg or more of oestradiol-17β. Under these conditions the stimulation of incorporation into the acid-soluble fraction is only 2–2.5-fold. When the purified RNA is separated on polyacrylamide gels the major increase in incorporation of radioactive precursor is found in rRNA and 4S RNA; the formation of the former has been followed from the 45S precursor. Preceding these events by at least 30min, however, is an increase in the incorporation of precursor into RNA species of very high molecular weight, which remained in the first few slices of the gel. The possible significance of these findings is discussed. The increased synthesis of rRNA in response to oestradiol-17β is more strongly inhibited by actinomycin D than the synthesis of other RNA species. Cycloheximide, depending on time of administration and dosage, inhibits either RNA synthesis or the maturation of rRNA.

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