DN.9693 COMPARED WITH PROSTACYCLIN AND PROSTAGLANDIN E1 IN SEVEN PLATELET TESTS

1987 ◽  
Author(s):  
J R O'Brien ◽  
M D Etherington ◽  
G P Salmon
Keyword(s):  
Bleeding Time ◽  
Prostaglandin E ◽  
Minor Effect ◽  
Membrane Glycoproteins ◽  
Clot Retraction ◽  
Platelet Factor ◽  
Active Concentration ◽  
A Minor ◽  
Induced Aggregation

A new drug, DN.9693, has low Km phosphodiesterase inhibitory properties. Its effect on seven broad spectrum platelet "function" tests has been compared with the effects of prostacyclin E1 (PGI1) and prostaglandin E (PGE ). The tests were (1) platelet aggregation induced by ADP, collagen, adrenaline, thrombin, arachidonic acid and ristocetin; (2) a new test in which platelets aggregate after adding distilled water to cause osmotic stress; (3) the loss of platelets washed in buffered saline; (4) clot retraction; (5) the glass bead column platelet retention test; (6) the in vitro filter "bleeding time" (see two other submitted abstracts); (7) the amount of platelet factor 4 (PF4) which "leaks" from platelets at room temperature.PGI2 inhibited all seven tests, 50% inhibition of the various tests required from 0.1 to 44ng/ml of PGI2. PGE1 also inhibited in all tests but on average required 18 times higher concentrations. Thus an increase in cAMP may be relevant to all these tests, but an understanding of the mechanisms involved is incomplete. DN.9693 inhibited only the first four tests; the equi-active concentration was about 600 times that of PGI2. DN.9693, 2.5μg/ml, caused 50% inhibition of ristocetin induced aggregation and at 4μg/ml had a minor effect on the filter bleeding time. Thus DN.9693 may affect the platelet membrane glycoproteins. In conclusion it is confirmed that PGE1 is less active than PGI^ but has similar activities. DN.9693 whenstudied in these tests has many, but notall, of the prostaglandin-like properties.

scholarly journals Platelet Functional Abnormalities: A Report of Two Familial Defects in Interaction Between Collagen and Platelets and ADP Release

Blood ◽  
1971 ◽  
Vol 38 (6) ◽  
pp. 745-758 ◽  
Author(s):  
A. G. PAPAYANNIS ◽  
E. J. WATSON-WILLIAMS ◽  
M. C. G. ISRAËLS
Keyword(s):  
Collagen Fibrils ◽  
Release Mechanism ◽  
Hemorrhagic Diathesis ◽  
Clot Retraction ◽  
Functional Abnormality ◽  
Platelet Factor ◽  
Prolonged Bleeding Time ◽  
Adp Release ◽  
Induced Aggregation

Abstract Two families have been studied, members of which have a lifelong hemorrhagic diathesis. In both families, a platelet functional abnormality has been found, with the coagulation mechanism intact. Findings common to both families were a prolonged bleeding time, reduced platelet adhesiveness, absence of the second wave of aggregation with ADP and reduced ADP release from platelets. The clot retraction, platelet factor 3 availability and aggregation of platelets with ADP in a final concentration of 1.0 and 20.0 µM were normal. The differences between the families were the platelet morphology, the in vitro adherence of platelets to collagen fibrils, the collagen-induced aggregation, and the thrombin-induced aggregation. In one of them, the Windle family, the platelets were abnormally large in size and showed a delayed adherence to collagen fibrils. The aggregation with collagen was either absent or feeble, and with thrombin, showed an abnormal pattern. In the other, the Hughes family, the platelets were morphologically normal and adhered to collagen fibrils normally. The aggregation with collagen initiated normally but usually did not proceed to completion and the aggregation with thrombin was normal. It appears that in the Windle family the main abnormality concerns the reaction between platelet and collagen and the condition is associated with impaired ADP-release mechanism and abnormal thrombin-platelet reaction, and in the Hughes family the ADP-release mechanism of platelets is defective. On the basis of current information, including that from these families, a classification of the various platelet functional abnormalities and methods for characterizing them is proposed.

scholarly journals Constitutional Thrombocytopathia with Abnormal Aggregation Different from Storage-Pool Disease and Aspirin-Like Syndrome

1977 ◽  
Author(s):  
J. Conard ◽  
M. Samama ◽  
B. Vargaftig ◽  
C. Lecrubier ◽  
J. Breton-Gorius ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Bleeding Time ◽  
Tolerance Test ◽  
Clot Retraction ◽  
Storage Pool ◽  
Dense Bodies ◽  
Arachidonic Acid Production ◽  
Storage Pool Disease ◽  
Induced Aggregation

A thrombocytopathi a associated with a lifelong hemorragic diathesis has been observed in a 18 years old woman. The bleeding time is prolonged. Platelet count and size, and clot retraction are normal. Adrenalin-induced aggregation is abolished and response to ADP and arachidonic acid are impaired. A storage-pool disease is unlikely since platelet ultrastructural aspects appear normal and the number of dense bodies is overnormal, that is confirmed by examination of platelets charged with mepacrine. The uptake of 14(c) serotonin is not increased and it is in correlation with abnormal fluorescence of meracrine-stained dense bodies. Contrasting with aspirin-like syndrome, the first phase aggregation is decreased and in vitro aspirin tolerance test abnormal. Finally, although platelets do not aggregate normally to arachidonic acid, production of Tromboxane A2 and transferable platelet aggregating activity are present. Hence, the thrombocytorathia reported here could not be classified, but a congenital defect is suspected.

Essential Athrombia

1975 ◽  
Vol 33 (02) ◽  
pp. 278-285 ◽  
Author(s):  
Şeref Inceman ◽  
Yücel Tangün
Keyword(s):  
Platelet Aggregation ◽  
Bleeding Time ◽  
Bleeding Tendency ◽  
Clot Retraction ◽  
Platelet Factor ◽  
Prolonged Bleeding Time ◽  
Normal Platelet ◽  
Aggregation Response ◽  
Platelet Disorder ◽  
Fibrinogen Content

SummaryA constitutional platelet function disorder in a twelve-year-old girl characterized by a lifelong bleeding tendency, prolonged bleeding time, normal platelet count, normal clot retraction, normal platelet factor 3 activity and impaired platelet aggregation was reported.Platelet aggregation, studied turbidimetrically, was absent in the presence of usual doses of ADP (1–4 μM), although a small wave of primary aggregation was obtained by very large ADP concentrations (25–50 μM). The platelets were also unresponsive to epinephrine, thrombin and diluted collagen suspensions. But an almost normal aggregation response occurred with strong collagen suspensions. The platelets responded to Ristocetin. Pelease of platelet ADP was found to be normal by collagen and thrombin, but impaired by kaolin. Platelet fibrinogen content was normal.The present case, investigated with recent methods, confirms the existence of a type of primary functional platelet disorder characterized solely by an aggregation defect, described in 1955 and 1962 under the name of “essential athrombia.”

Daunorubicin and Platelet Function

1981 ◽  
Vol 45 (01) ◽  
pp. 038-042 ◽  
Author(s):  
M E Pogliani ◽  
R Fantasia ◽  
G Lambertenghi-Deliliers ◽  
E Cofrancesco
Keyword(s):  
Electron Microscope ◽  
Cellular Membrane ◽  
Hemorrhagic Diathesis ◽  
Clot Retraction ◽  
Freezing And Thawing ◽  
Platelet Factor ◽  
High Doses ◽  
Very High ◽  
Platelet Functions

SummaryThe influence of Daunorubicin on some platelet functions in vitro was investigated, using different concentrations of the drug (0.01-0.02-0.04 μg/ml). Daunorubicin was shown to inhibit Collagen and Thrombin induced platelet aggregation and the intensity of inhibition depended on both drug concentration and the time of preincubation.Daunorubicin was also shown to inhibit the release reaction, the platelet prostaglandin pathway and the availability platelet factor 3; the drug at concentrations for clinical use does not damage the platelet membrane, as is the case with the freezing and thawing test, in platelet uptake of 14C-serotonin and as confirmed by the electron microscope. When very high doses (0.16 mg) of Daunorubicin are used, lysis of the platelets can be observed and this is confirmed under the electron microscope by the presence of empty platelets with fractures at the level of the cytoplasmic membrane.Finally, Daunorubicin causes irreversible inhibition of reptilase clot-retraction, even if this is less severe than with Vincristine. Working with gel-filtered platelets, it would appear that the inhibition exercised by the drug on platelet reactions is not caused through modifications in Ca++ metabolism.The authors suggest that Daunorubicin, at the dosages used clinically, induces in vitro thrombocytopathy without damaging the cellular membrane as confirmed by the electron microscope.This impairment of platelet functions could play a part in hemorrhagic diathesis observed during Daunorubicin therapy.

scholarly journals Roles of Transcription Factor Mot3 and Chromatin in Repression of the Hypoxic Gene ANB1 in Yeast

2000 ◽  
Vol 20 (19) ◽  
pp. 7088-7098 ◽  
Author(s):  
Alexander J. Kastaniotis ◽  
Thomas A. Mennella ◽  
Christian Konrad ◽  
Ana M. Rodriguez Torres ◽  
Richard S. Zitomer
Keyword(s):  
Binding Site ◽  
Regulatory Region ◽  
Direct Interaction ◽  
Minor Effect ◽  
Histone H4 ◽  
Coding Region ◽  
Basal Transcriptional Machinery ◽  
In The Wild ◽  
A Minor

ABSTRACT The hypoxic genes of Saccharomyces cerevisiae are repressed by a complex consisting of the aerobically expressed, sequence-specific DNA-binding protein Rox1 and the Tup1-Ssn6 general repressors. The regulatory region of one well-studied hypoxic gene,ANB1, is comprised of two operators, OpA and OpB, each of which has two strong Rox1 binding sites, yet OpA represses transcription almost 10 times more effectively than OpB. We show here that this difference is due to the presence of a Mot3 binding site in OpA. Mutations in this site reduced OpA repression to OpB levels, and the addition of a Mot3 binding site to OpB enhanced repression. Deletion of the mot3 gene also resulted in reduced repression of ANB1. Repression of two other hypoxic genes in which Mot3 sites were associated with Rox1 sites was reduced in the deletion strain, but other hypoxic genes were unaffected. In addition, the mot3Δ mutation caused a partial derepression of the Mig1–Tup1-Ssn6-repressed SUC2 gene, but not the α2–Mcm1–Tup1-Ssn6-repressed STE2 gene. The Mot3 protein was demonstrated to bind to the ANB1 OpA in vitro. Competition experiments indicated that there was no interaction between Rox1 and Mot3, indicating that Mot3 functions either in Tup1-Ssn6 recruitment or directly in repression. A great deal of evidence has accumulated suggesting that the Tup1-Ssn6 complex represses transcription through both nucleosome positioning and a direct interaction with the basal transcriptional machinery. We demonstrate here that under repressed conditions a nucleosome is positioned over the TATA box in the wild-type ANB1promoter. This nucleosome was absent in cells carrying arox1, tup1, or mot3 deletion, all of which cause some degree of derepression. Interestingly, however, this positioned nucleosome was also lost in a cell carrying a deletion of the N-terminal coding region of histone H4, yet ANB1expression remained fully repressed. A similar deletion in the gene for histone H3, which had no effect on repression, had only a minor effect on the positioned nucleosome. These results indicate that the nucleosome phasing on the ANB1 promoter caused by the Rox1–Mot3–Tup1-Ssn6 complex is either completely redundant with a chromatin-independent repression mechanism or, less likely, plays no role in repression at all.

scholarly journals Platelet Dysfunction with Glutathione Reductase Deficiency After 1,3-Bis(2 Chloroethyl)-l-Nitrosourea

1977 ◽  
Author(s):  
R. McKenna ◽  
T. Ahmad ◽  
H. Frischer
Keyword(s):  
Glutathione Reductase ◽  
Platelet Dysfunction ◽  
Dose Response Relationship ◽  
Control Activity ◽  
Platelet Factor ◽  
Antitumor Chemotherapy ◽  
Glutathione Reductase Deficiency ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Induced Aggregation

We have previously shown that patients receiving antitumor chemotherapy with 1,3-bis-(2 chloroethyl)-1-nitrosourea (BCNU) rapidly acquire a severe generalized glutathione reductase (GSSG-R) deficiency. We now report that when platelets were exposed in vitro to BCNU (30 minutes, 37°, at 10-3 M, six separate studies), the resulting GSSG-R deficiency was associated with marked impairment of platelet aggregation in response to ADP (1 μM and 3 μM), to epinephrine and to collagen (all p’s< 0. 001). Platelet factor 3 availability was also markedly reduced (p<0.001); prothrombin consumption and glass adhesiveness were unaffected. In additional experiments to evaluate the dose response relationship, epinephrine induced aggregation was abnormal at 5 × 10-6 M BCNU, ADP (1 μM) induced aggregation was abnormal at 10-5 M BCNU, while ADP (3 μM) and collagen aggregation became abnormal at 5 × 10-5 M BCNU. GSSG-R deficiency (less than 11% of control activity), without glucose-6-phosphate dehydrogenase and 6-phosphogluconic dehydrogenase deficiencies, preceded all platelet abnormalities. We have demonstrated that a specific platelet GSSG-R deficiency after BCNU precedes the development of severe platelet dysfunction.

FACTOR XIII IS NOT INVOLVED IN THE PLATELET ADHESION TO COLLAGEN

1987 ◽  
Author(s):  
K Kariya ◽  
Y Sawada ◽  
K Ueno ◽  
I Kudo ◽  
M Aihara ◽  
...  
Keyword(s):  
Factor Xiii ◽  
Platelet Adhesion ◽  
Bleeding Time ◽  
Type I Collagen ◽  
Rabbit Serum ◽  
Type I ◽  
Platelet Factor ◽  
Normal Plasma ◽  
Von Willebrand

We have reported that the adhesion of human formalin-fixed washed platelets (FWP) to collagen was enhanced by von Willebrand factor but inhibited by plasma fibronectin (Thromb. Res. 44, 1986). Recently, platelet factor XIII is reported to be a receptor for collagen (Saito, JBC, 261, 1986). To investigate the role of factor XIII in the interaction between platelets and collagen, effect of purified XIII or rabbit anti-XIIIa on the adhesion of FWP to collagen or on the in vitro bleeding time was studies. FWP adhesion was measured by either collagen-coated glass beads column or aggregometric method using bovine type I collagen (Ethicon Inc., Dr. Kronenthal). In vitro bleeding time was measured with Thrombostat-4000 (VDG-VONDERGOLTZ), in which citrated whole blood as a sample and ADP, CaCl2 and rat type I collagen as the reagents were used. Platelet adhesion to the collagen immobilized column (1,300 ug collagen, flow rate 5 ml/min) was not changed by the addition of purified XIII (Fibrogammin, Hoechst); the adhesion were 42.7 ± 1.7% in the presence of 1% human serum albumin, 42,0 ± 0.3%, 43,0 ± 1.4% in the presence of 1 or 2 u/ml factor XIII. Furthermore, the adhesion of FWP which was added by 1:100 rabbit anti-XIIIa was 42.3 ± 1.4% and not different from that of control rabbit serum (46.1 ± 1.3%). Similar results were also obtained with different technique using aggregometer. No significant change on in vitro bleeding time was observed after the addition of 1:100 rabbit anti-XIIIa to citrated normal blood. When the binding of factor XIII to the collagen was investigated by batch method, 17%, 23% and 54% of factor XHIa in normal plasma bound to 250, 500 and 1000 ug/ml collagen, respectively. These data suggest that factor XIII is not involved in the platelet adhesion to the type I fibrillar collagen, while factor XHIa in normal plasma binds to the collaeen.

scholarly journals The Effect of Chromium on Platelet Function In Vitro

Blood ◽  
1970 ◽  
Vol 35 (5) ◽  
pp. 659-668 ◽  
Author(s):  
HERMAN E. KATTLOVE ◽  
THEODORE H. SPAET
Keyword(s):  
Connective Tissue ◽  
Platelet Function ◽  
Adenine Nucleotides ◽  
Adenosine Diphosphate ◽  
Sodium Chromate ◽  
Platelet Factor ◽  
Survival Studies ◽  
Induced Aggregation ◽  
Platelets Function

Abstract Sodium chromate inhibits platelet function in vitro. The primary effect is inhibition of connective tissue-induced aggregation. In addition, the primary wave of epinephrine-induced aggregation is moderately inhibited and adenosine diphosphate-induced aggregation is mildly inhibited. The effect on connective tissue-induced aggregation is due to inhibition of the platelet "release reaction"; chromate inhibited the release of adenine nucleotides, 14C labeled serotonin and the activation of platelet factor III normally caused by connective tissue. The amount of chromium which must be bound to platelets to inhibit aggregation is 10-100 times the amount of radioactive chromium bound to platelets under the usual conditions of labeling for survival studies. However, this does not imply that chromium labeled platelets function normally.

scholarly journals Observations on the Thrombocytopenia Due to Hypersensitivity to Quinidine

Blood ◽  
1954 ◽  
Vol 9 (2) ◽  
pp. 134-143 ◽  
Author(s):  
PERCY BARKHAM ◽  
LEANDRO M. TOCANTINS
Keyword(s):  
Sodium Citrate ◽  
Bleeding Time ◽  
Test Dose ◽  
Complete Inhibition ◽  
Normal Blood ◽  
Clot Retraction ◽  
Thrombocytopenic Purpura

Abstract Studies are reported on a patient who developed thrombocytopenic purpura following quinidine therapy. Quinidine caused lysis of the patient’s platelets in vitro within 40 minutes and complete inhibition of clot retraction. Platelet lysis preceded platelet agglutination. Increasing the concentration of the sodium citrate used as anticoagulant inhibited the in vitro action of the quinidine. No thrombocytolytic effect of the patient’s serum with quinidine could be shown when tested against normal blood. A test dose of quinidine administered orally after the patient had recovered from the thrombocytopenia produced a profound decrease in the number of platelets within 90 minutes, associated with a prolongation of the bleeding time and disappearance of clot retraction. The in vitro hypersensitivity to quinidine persisted for at least four weeks after recovery from the purpura; after six weeks it could no longer be demonstrated.

scholarly journals PDK1 selectively phosphorylates Thr(308) on Akt and contributes to human platelet functional responses

2014 ◽  
Vol 111 (03) ◽  
pp. 508-517 ◽  
Author(s):  
Carol Dangelmaier ◽  
Bhanu Kanth Manne ◽  
Elizabetta Liverani ◽  
Jianguo Jin ◽  
Paul Bray ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein A ◽  
Human Platelets ◽  
Clot Retraction ◽  
Functional Responses ◽  
Atp Secretion ◽  
Dependent Protein ◽  
Induced Aggregation

Summary3-phosphoinositide-dependent protein kinase 1 (PDK1), a member of the protein A,G and C (AGC) family of proteins, is a Ser/Thr protein kinase that can phosphorylate and activate other protein kinases from the AGC family, including Akt at Thr308, all of which play important roles in mediating cellular responses. The functional role of PDK1 or the importance of phosphorylation of Akt on Thr308 for its activity has not been investigated in human platelets. In this study, we tested two pharmacological inhibitors of PDK1, BX795 and BX912, to assess the role of Thr308 phosphorylation on Akt. PAR4-induced phosphorylation of Akt on Thr308 was inhibited by BX795 without affecting phosphorylation of Akt on Ser473. The lack of Thr308 phosphorylation on Akt also led to the inhibition of PAR4-induced phosphorylation of two downstream substrates of Akt, viz. GSK3β and PRAS40. In vitro kinase activity of Akt was completely abolished if Thr308 on Akt was not phosphorylated. BX795 caused inhibition of 2-MeSADP-induced or collagen-induced aggregation, ATP secretion and thromboxane generation. Primary aggregation induced by 2-MeSADP was also inhibited in the presence of BX795. PDK1 inhibition also resulted in reduced clot retraction indicating its role in outside-in signalling. These results demonstrate that PDK1 selectively phosphorylates Thr308 on Akt thereby regulating its activity and plays a positive regulatory role in platelet physiological responses.

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