bluuebunny/crossref_metadata_2025 huggingface dataset:
A Prospective Trial of Sulfinpyrazone After Peripheral Vascular Surgery
Authors: Blakely J.A. , Pogoriler G.
Published: May 2019

169 patients were randomly allocated to Sulfinpyrazone or placebo after peripheral vascular surgical procedures. Randomization was stratified for surgeon and type of operation (endarterectomy, vein graft, or prosthesis) and aorto-iliac or femoral popliteal site. Treatment was begun with Sulfinpyrazone 200 mgs. t.i.d. or equivalent placebo. Platelet tests were performed at intervals and patients with active collagen aggregation were given increments to 1200 mgs. daily or equilivent placebo. Patients were followed for up to 3 years. Claudication distances, peripheral pulses, readmissions, and returns to surgeon were documented at intervals. Three endpoints were assessed without knowledge of treatment category; occlusion at operated site, occlusion in same leg, and all peripheral vascular events, as well as other episodes of vascular disease. 137 patients had femoral popliteal and 27 had aortoiliac surgery. There was no evidence of benefit in either group with respect to any of the endpoints. There was 1 death in the treated group and 2 deaths in the control group. Suspect drug toxicity was similar in treatment and control groups (22 vs. 19) although more patients were withdrawn from the treatment group as a result (11 vs. 50, mostly because of rash, dyspepsia, and nausea.

This study suggests that Sulfinpyrazone does not prolong patency after peripheral vascular surgery.
Studies on Ristocetin Induced Platelet Aggregation
Authors: Nachman R.L. , Jaffe E.A. , Weksler B.B.
Published: May 2019

Human platelets washed and fixed in paraformaldehyde aggregate in the presence of the antibiotic ristocetin and normal plasma. This aggregation response is abolished after digestion of the fixed platelets with chymotrypsin. Antisera to fixed washed platelets were produced in rabbits and absorbed with chymotrypsin-treated, fixed washed platelets. Monovalent Fab fragments obtained from the isolated γ-globulin fractions of the antisera blocked ristocetin-induced aggregation of fixed washed platelets in buffer and normal platelets in platelet-rich plasma. By double-antibody immunoprecipitation, it was shown that the antibody which blocked the ristocetin reaction interacted with a platelet membrane surface protein of mol.wt.155,000. Partially purified preparations of membrane glycoprotein I obtained from wheat germ affinity columns block the ristocetin reaction. The results suggest that the glycoprotein I complex on the surface of the human platelet mediates ristocetin-induced von Willebrand factor-dependent platelet aggregation.
Cellular Thrombin Binding
Authors: Martin B.M. , Detwiler T.C.
Published: May 2019

The clot promoting enzyme thrombin induces cell-specific changes in washed human blood platelets and cultured chick embryo fibroblasts. In the attempt to understand the mechanism of the enzyme-cell reaction, the association of 125I labeled human α-thrombin with these cells was studied. The conditions chosen for the binding studies enabled parallel investigation of the effect of thrombin on these cells. The results indicate that for both cell types studied, most of the thrombin remains free in solution, however the thrombin binding characteristics of these cells appear to be different. The binding of thrombin to platelets is rapid, with maximum binding occurring within 15 sec. Thrombin is bound reversibly to platelets and rapidly dissociates by dilution of the reaction mixture or by the addition of unlabeled thrombin. The thrombin platelet association can be described as a complex equilibrium with the apparent number of binding sites and dissociation constants dependent on the thrombin comcentration. In contrast, the thrombin binding to avian fibroblasts is slow, with maximum binding occurring within 4 to 8 hours. While the enzyme is also reversibly bound to fibroblasts, it is more tightly associated with these cells since it is not easily removed by washing the cultured cells. Furthermore, the majority, 70-80% of the bound enzyme is not removed by trypsin and appears to be inside the cell. The cell associated thrombin has the same molecular weight as native α-thrombin and retains catalytic activity. Cell fractionalion studies show that the majority of the cell-associated thrombin is located in the nuclear fraction since the 125I-label co-purifies with radiolabeled thymidine.
Platelet Alpha-Adrenergic Receptors: Direct Identification by [3H] Dihydroergocryptine
Authors: Williams L.T. , Newman K.P. , Lefkowitz R.J.
Published: May 2019

Platelet aggregation induced by epinephrine is an α-adrenergic response which is blocked by α-adrenergic antagonists. We now report the successful identification of human platelet α-adrenergic receptors (AR) by direct binding studies with the potent α-adrenergic antagonist [3H] dihydroergocryptine (DHE). Specific DHE binding to platelet AR was assayed by incubating DHE with platelet lysates for 17' at 25°C. Binding of DHE had the specificity expected of binding to AR. The α-adrenergic agonist (-)epinephrine, had a high affinity for the binding site, causing half-maximal inhibition of DHE binding at a concentration (EC50) of 0.8µM. A series of α-adrenergic agonists competed for the binding sites in an order of potency ((-) epinephrine> (-)norepinephrine> (-)isoproterenol) identical to their order of potency in stimulating α-adrenergic mediated platelet aggregation. Competition for DHE binding sites by α-adrenergic agonists was stereospecific, the (-) stereoisomers of epinephrine and norepinephrine being 7-10 fold more potent than the corresponding (+) stereoisomers. Tie α-adrenergic antagonist phentolamine inhibited binding with an EC50 of 0.04µM while β-adrenergic antagonists practolol, propranolol and dichlorisoproterenol competed only at very high concentrations (10 µ M). Other α-adrenergic agents such as phenylephrine (EC50 = 4μ M) and Clonidine (EC50 = .05 μM) also competed for the binding sites. Dopamine (EC50=9μM) and serotonin (EC50 = 90μM) competed for binding at high concentrations. Catecholamine metabolites and structural analogues devoid of α-adrenergic activity did not compete for the binding sites. The results indicate that human platelet AR can be directly labeled and studied with DHE.
Interaction of Platelets with Serotonin and Dopamine
Authors: Drummond A.H. , Olverman H.J. , MacIntyre D.E. , Gordon J.L.
Published: May 2019

Serotonin and dopamine are transported by platelets, and serotonin also stimulates platelets to change shape. Km values for transport are around 1 µM for serotonin and 40 μM for dopamine. Both amines also enter platelets by diffusion. Antidepressant drugs (e.g. chlorimipramine; Lilly 110140) inhibit serotonin and dopamine uptake with equal potency and also block the stimulatory action of serotonin, but serotonin antagonists (e.g. methysergide; d-lysergic acid diethylamide) which are potent inhibitors of the serotonin-induced shape-change do not affect the transport of serotonin or dopamine. Binding studies with [3H]-serotonin show heterogeneity of receptors: one site has characteristics consistent with the uptake carrier, and another is selectively blocked by serotonin antagonists. We conclude that dopamine is transported into platelets by the serotonin carrier (although with a much lower affinity) and that a separate site mediates platelet stimulation by serotonin. The concept of platelets as models for aminergic neurons in the central nervous system may be valid for serotonin but does not hold for dopamine.
Abnormal Platelet Ultrastructure in Fulminant Hepatic Failure
Authors: Bullock G. , Weston M.J. , Rubin M.H. , Roberts J. , Langley P.G. , White Y. , Williams R.
Published: May 2019

Platelets obtained from eight patients with varying degrees of liver damage have been studied with respect to their ultrastructure. These platelets were isolated from platelet-rich plasma which had been utilised in the pharmacological studies described by Dr. Weston (previous abstract) and were compared with control platelets isolated from five normal subjects. The latter were chosen for normal bleeding times and response of their platelets to aggregation with ADP and collagen.

Marked differences were seen between control platelets and those from the test group in that there was an alteration in the microtubular content and disposition. In addition, these changes were partially reversed during the recovery period suggesting that production of new normal platelets was taking place. This is one of the few conditions where platelet structure has been correlated with a clinical disorder.
Furosemide, Fibrinolytic Activity and Urokinase Excretion
Authors: Chohan I.S. , Singh I. , Vermylen J. , Verstraete M.
Published: May 2019

Plasma fibrinolytic activity, as measured by the fibrin-plate method, is enhanced after an intravenous injection of 40 mg furosemide. The effect is evident within 30 minutes of the injection and attains a peak after 6 hours. If a second injection of furosemide is given at this stage, the increased fibrinolytic activity persists, and a slightly higher peak than the first is obtained again 6 hours after this injection. After the furosemide injection, there is an initial decrease of urokinase excretion which returns to normal after 3 to 6 hours.

The decrease of urokinase excretion is attributed to a dilution effect during increased diuresis and the rise in fibrinolytic activity by furosemide is attributed to its vasodilatory activity and cyclic-AMP phosphodiesterase inhibitory capacity. It also appears related to the Hageman factor dependent pathway of fibrinolysis. In the treatment of high altitude pulmonary oedema, furosemide restores factor XII and fibrinolytic activity, which are both depressed in this disease (I. Singh and I.S. Chohan, Int. J. Biometeor. 18, 33, 1974).
Furosemide and Platelet Functions
Authors: Chohan I.S. , Singh I. , Vermvlen J. , Verstraete M.
Published: May 2019

Furosemide inhibits primary platelet aggregation by adenosine-5'-diphosphate and prolongs the latent period before Thrombofax- or collagen-induced platelet aggregation, both in vitro and ex vivo. Furosemide also inhibits the release of platelet factor 4 and 14C-serotonin. The inhibitory concentrations of furosemide in vitro range between 0.5 and 2.5 mM. The ex vivo effects were obtained after an intravenous injection of 40 mg furosemide.

The furosemide concentrations required for ex vivo inhibition are hundred fold lower than those required for in vitro effect. This suggests in vivo metabolic effects of this drug, such as, calcium ions shifts, or action of other metabolic products of furosemide. In support of this concept platelet aggregation was found more disturbed six hours than 10 minutes after injection of the drug.
Effect of Oral Contraceptives on Factor VIII Clotting Activity and Factor VIII Related Antigen in Known Haemophilia Carriers
Authors: Stableforth Penelope , Dormandy Katharine M. , Hardisty Roger M.
Published: May 2019

The factor VIII clotting activity (VIII:C) and factor VIII related antigen (VIIIR:AG) were determined on 3 occasions in 14 known haemophilia carriers, each paired with an age-matched control, both groups being on oral contraceptives (O.C.), and 18 known carriers each paired with an age-matched control, neither group on O.C. The VIII:C/VIIIR:AG ratio was less than 0.7 in 14 out of 14 carriers on O.C. and greater than 0.7 in 13 out of 14 controls on O.C. 16 out of 18 carriers not on O.C. had a ratio less than 0.7 while 16 out of 18 controls not on O.C. had a ratio greater than 0.7. Statistical analysis showed that there was no significant difference in the accuracy of carrier detection in this group of known carriers, whether or not they were on oral contraceptive pills.
Studies on Spontaneous Platelet Aggregation (PAT III) in Patients with Vascular Disease
Authors: Krzywanek H.J. , Breddin K.
Published: May 2019

Aggregation tests were performed in 345 patients with peripheral occlusive arterial disease (PAD), 274 patients with coronary heart disease (CHD), and 502 diabetics (D). 263 healthy volunteers (N) served as controls. As in previous studies an age dependent increase of strongly enhanced spontaneous platelet aggregation in obviously healthy subjects can be demonstrated, reaching 28% in the 50-59 years’age group. In the various patient groups the incidence of enhanced aggregation is much higher throughout all age groups than in the control s.

The overall incidence of missing spontaneous platelet aggregation vs. strongly enhanced aggregation is summarized below. The difference between normals and the various patient groups is significant (X2-test, α<0.0001).

A prospective investigation has been started to establish whether enhanced spontaneous platelet aggregation is a risk factor and an early indicator of progressive atherosclerosis.
Time and Temperature Dependent Changes of Platelet Aggregation
Authors: Breddin K. , Krzywanek H.J.
Published: May 2019

ADP-, collagen and epinephrine-induced aggregation change markedly if citrate blood or PRP are kept at different incubation temperatures or/and if the time interval between blood sampling and testing varies. With a growing time interval the response of PRP to ADP, collagen or epinephrine increases. Desaggregation after ADP-aggregation decreases with time. If PRP is incubated at 4°C or 10°C aggregation is increased in comparison with room temperature. At 37°C aggregation is markedly inhibited. This inhibitory effect is almost fully reversible several hours after blood sampling. Corresponding results were obtained with PAT III, measuring spontaneous aggregation tendency. Morphologic platelet changes show some correlation with the time and temperature dependent changes of the aggregation pattern. In clinical studies the time interval between blood sampling and testing and the incubation temperature of PRP should be strictly controlled. If enhanced platelet aggregation is to be studied the time interval between venepuncture and performance of the test should be 30 - 60 min for ADP-or collagen-induced aggregation and between 90 and 360 min for PAT III. PRP should always be kept at 20 - 25°C.
The Effect of Endotoxin on Haemostasis in Normal and Leukemic Rats
Authors: Rasche H. , Hoelzer D.
Published: May 2019

Platelet count, fibrinogen and antithrombin levels were studied in normal rats (group A), in rats with the experimental rat leukemia L 5222 in an early phase (group B) and in a final phase (group C) of the disease. The animals were randomized and treated with o.5 mg endotoxin or placebo as a single i.v.injection. Four hours later blood samples were taken for laboratory tests. The results were as follows: 1. Groups A and B did not differ in the laboratory parameters under investigation 4 hours after injection of saline as a placebo. 2. Leukemic rats of group C treated with saline had significantly elevated levels of fibrinogen and antithromin as well as reduced platelet count compared to their normal counterparts. 3. The injection of endotoxin resulted in a comparable decrease of platelets in normal and leukemic animals. 4. The injection of endotoxin led to a decrease of fibrinogen levels in all groups. The most pronounced decrease was observed in group B, while there was only a slight fall in group C. The antithrombin levels of group A and B were not influenced by endotoxinaemia. The elevated level of antithrombin in group C, however, was completely normalized after a single injection of endotoxin.

It can be concluded from these results that the haemostatic system of rats in the early phase of the leukemia L 5222 is more susceptible to endotoxin than that of normal controls. Possibly due to marked elevated levels of antithrombin rats in the final phase of the disease seem to be protected against the aggravation of the haemostatic defect by endotoxin.
Comparison of Risk Factors in Patients with Normal Arteries and Coronary Disease After Infarction
Authors: Durairaj S. K. , Khan A. H. , Haywood L. J.
Published: May 2019

Risk factors were compared in 42 patients (pts) with coronary artery disease (CAD) and 18 with radiographically patent arteries (RPA) on angiography performed three weeks to six months after documented myocardial infarction (Ml). All pts had typical clinical and laboratory findings during the acute attack. All pts were below age 50 and both groups had a similar distribution of racial background (Caucasian, black and Mexican-American). Psychiatric problems were not more frequent in either group. The data demonstrated a high prevalence of standard risk factors in the CAD group for hypertension (28 of 42 = 67%), hypercholesterolemia (25 of 42 = 60%) and smoking (17 of 42 = 64%), and similarly high prevalence of smoking (16 of 18 = 89%), heavy labor (12 of 18 = 61%) and obesity (9 of 18 = 50%) in the RPA group. Factors significantly more common in the CAD group as compared to the RPA group by the Chi Square test were:Hypertension (P < 0.001), hypercholesterolemia (P < 0.001), diabetes (P < 0.001), and family history (P < 0.05). Factors more common in the RPA group were heavy alcohol consumption (P < 0.001), smoking (P < 0.05), heavy laborer occupation (P < 0.001) and obesity (P < 0.001). The data suggest that risk factor screening would identify individuals at risk from coronary artery disease but would be unreliable in identifying individuals at risk for MI with RPA. Further study is indicated to determine what factors operate to produce ischemia and infarction in the RPA group of pts.
Treatment of Venous Thrombosis with Streptokinase: Review of U.S. Clinical Studies
Authors: Maloy J.W. , Mehta D.J. , Boksay I.J.E.
Published: May 2019

Treatment of venous thrombosis with streptokinase followed by anticoagulants was compared to treatment with anticoagulants alone. The study was performed by several investigators following a common protocol. Results of venographic examinations before and after treatment were compared by radiologists unaware of the treatment assigned to provide the primary comparison of efficacy. Streptokinase therapy was found to be significantly (p<.05) superior to anticoagulants alone in achieving clearance of occluded veins. Approximately 60% of patients treated with streptokinase experienced significant clearance of venous thrombi compared to only 18% of control patients. The incidences of complete clearance of thrombi was 22% in patients treated with streptokinase compared to 5% in patients treated only with anticoagulants. The incidence of severe spontaneous (unrelated to invasive procedures) bleeding occurred at a similar incidence rate in both groups of patients. Bleeding at invasive sites, low-grade fever, and mild allergic manifestations (e.g. headache, nausea, itching, etc.) occurred more often in patients treated with streptokinase but rarely interfered with the treatment procedure. The significantly increased benefit achieved with streptokinase followed by anticoagulants was concluded to outweigh the risk of minor complications and the relatively low risk of severe complications.
Boolean Algebra, Major Defects, Minor Defects, and Hemostasis
Authors: Hathhorn Thomas K.
Published: May 2019

The purpose of this paper is to show how simple application of Boolean algebra to hemostasis can be used in the diagnosis and teaching of problems in coagulation. By utilizing a simple Venn diagram with plasma factors, hemostatic plug and vascular factors (includes local lesions) as categories and dividing defects in these areas arbitrarily into major and minor defects, a simple holoistic approach is revealed. Any major defect (e.g. < 5% AHG or a large lesion) may result in persistent hemorrhage. One minor defect in any area of the diagram does not alter hemostasis clinically or cause spontaneous or persistent hemorrhage. Two minor defects or more in any area may be associated with spontaneous hemorrhage (e.g. 20% AHG and aspirin ingestion). If one sees a bleeding patient and one minor defect is noted, look for a second minor defect. Utilizing this approach to common everyday problems in coagulation with trauma or pathologic lesions constituting one defect reveals the submerged part of the iceberg of treatable hemorrhagic disease. Listing of major and minor defects with illustrative case histories will be presented.
‘In Vivo’ and ‘In Vitro’ Effects of Some Vasoactive Drugs on Platelet Function and on Coagulation/Fibrinolysis System
Authors: Dettori A.G. , Ponari O. , Manotti C. , Megha A. , Pini M.
Published: May 2019

Three substances widely used as vasoactive drugs are known to have an inhibiting effect on platelet aggregation ‘in vitro’. We investigated the changes induced on thrombelastogram, routine clotting tests, euglobulin lysis time (ELT), platelet count, aggregation, and adhesiveness by i, v. administration of these drugs to man. The same indices were also studied ‘in vitro’ by adding comparable concentrations of the substances to human blood or plasma.

Aminophilline did not produce any significant variation in ADP-or collagen-induced aggregation either ‘in vitro’ (50 to 200 μg/ml) or ‘in vivo’ (240 mg). A trend to disaggregation was seen only in a few cases. Shorter ELT were found 30 and 120 minutes after injection.

A papaverine derivative (Metaverinum, 150 mg) showed a similar ‘in vivo’ pattern: minor changes in platelet function tests and a moderate activation of fibrinolysis were seen. The drug acted ‘in vitro’ as a powerful inhibitor of aggregation (from 30 µg/ml)while fibrinolysis was only activated at the highest concentration (120 µg/ml).

Bencyclan, capable of inhibiting platelet function ‘in vitro’ at very low concentrations (0.25µM) did not show similar effects ‘in vivo’ (50 mg) apart from a reduced platelet adhesiveness to glass.
Influence of Imidazole Carboxamide on Platelet Function
Authors: Kubisz P. , Klener P. , Cronberg S.
Published: May 2019

Imidazol carboxamide (DTIC, NSC-45388) is a cytostatic drug used in the treatment of malignant melanoma under the trade name of DacarbazinR, MSD. Its influence on platelet function, blood coagulation and fibrinolysis was investigated in vitro.

At a concentration of 160 µg/ml it inhibited the increase in light transmission induced in platelet-rich plasma by standardized freezing and thawing. It also retarded the retraction of reptilase clots. This therefore indicated a stabilizing effect on the platelets at this dosage.

At a concentration of 40 μg/ml the drug did not significantly influence the platelet function in vitro.

This concentration corresponds to therapeutic plasma levels. At current dosage of the drug any bleeding tendency due to platelet dysfunction therefore seems unlikely.
Prostaglandin-Endoperoxides and Cyclic 3′-5′-AMP in Platelets of Patients with Hypercoagulability and Shock
Authors: Matthias F.R.
Published: May 2019

To get more insight in platelet function of patients suffering from insufficiency of the circulation together with intravascular fibrin formation as a sign of a stimulated coagulation system, the following parameters were determined: 1. the prostaglandin-endoperoxide formation of platelets in response to N-ethylmaleimide and collagen measured as malondialdehyde; 2. the c-AMP content of platelets and plasma according to the Gilman method; 3. the stimulating effect of prostaglandin E1 on the platelets adenylate-cyclase activity; 4. the collagen induced platelet aggregation.

Platelet aggregation was reduced. The prostaglandin-endoperoxide formation was unchanged or elevatedin comparison to normal donors. Plasma c-AMP was increased, whereas the platelet c-AMP content was unaltered. Adenylate cyclase activity in response to prostaglandin E1 was reduced. Platelet function recovered concomitantly with the improvement of the circulation and the clotting parameters.
A Study of Lymphocyte Transformation as a Mechanism for Spontaneous Factor VIII Inhibitor Formation
Authors: Katz J. , Lea R. , Gomperts E.D.
Published: May 2019

Two elderly patients with a bleeding tendency due to spontaneous Factor VIII inhibition were investigated. An in vitro study was designed to investigate lymphocyte transformation and the production of Factor VIII inhibitor. Blood samples from patients were separated on a ficoll-hypaque gradient and the mononuclear cells were cultured with haemophiliac plasma. Factor VIII concentrate and normal plasma as sources of Factor VIII antigen. The results showed that the patients lymphocytes were stimulated by some samples of haemophiliac plasma, but not by the Factor VIII concentrates or normal plasma. However, normal control lymphocytes were similarly stimulated by these samples of haemophiliac plasma suggesting that immune complexes were present in the haemophiliac plasma and probably caused the stimulation. Furthermore, the patients lymphocytes were stimulated with phytohaemagglutinin candida and tuberculin and normal responses were obtained with AB serum. However, the sera of both patients inhibited candida and tuberculin stimulated lymphocyte cultures and the inhibition correlated with the presence of Factor VIII inhibitor. In this study a cellular immune mechanism for the production of spontaneous Factor VIII inhibitor could not be demonstrated, however a serum inhibitor of candida and tuberculin stimulated lymphocyte cultures was found.
Effect of Thrombin on Factor VIII/VON Willebrand Factor (FVIII/vWF)
Authors: Switzer Mary Ellen , McKee P.A.
Published: May 2019

The sodium dodecyl sulfate (SDS) gels and immunological properties of FVIII/vWF and thrombin-activated (thr-act) FVIII/vWF are identical. Hence thrombin must either modify FVIII/vWF by very minor proteolysis or cleave only a few FVIII/vWF molecules. The procoagulant (PC) activity of FVIII/vWF and thr-act FVIII/vWF eluted sharply in the void volume (Vo) from 4% agarose in 0.15 M NaCl, with >65% loss of the PC activity of the thr-act FVIII/vWF by 3 hrs. The PC activity of FVIII/vWF and thr-act FVIII/vWF was stabilized by 0.25 M CaCl2. When FVIII/vWF and thr-act FVIII/vWF were filtered on 4% agarose in 0.25 M CaCl2, the protein eluted in the Vo, but most of the PC activity eluted later in a region of little detectable protein; however, the delayed PC peak from thr-act FVIII/vWF was greatly enhanced above control levels. Nonreduced, neither activity peak protein entered a 7.5% SDS gel. After reduction, the gel pattern for the PC activity peak protein from FVIII/vWF showed major bands of 195x, 79x, 61x, 51x and 18x (103) molecular weight (MW) and several minor bands >100,000 MW. The reduced PC protein from thr-act FVIII/vWF lacked all bands >100,000 MW, but the four lower MW bands were present and well-resolved. Thrombin activation did not affect the vWF activity which was proportional to protein concentration throughout any chromatogram; the 195,000-dalton subunit was not necessary for vWF activity. FVIII/vWF, which had the peak PC activity in the Vo and no other PC activity peak on 4% agarose-0.25 M CaCl2, was thr-act before filtration under the same conditions. Then, the greatly enhanced PC activity eluted well after the Vo, with <10% PC activity in the Vo. We conclude that modification of a few FVIII/vWF molecules by thrombin and their stabilization by 0.25 M CaCl2 causes the PC peak that elutes aberrantly from 4% agarose-0.25 M CaCl2.
Increase in Platelet Volume and Aggregability in Adenosine Diphosphate Induced Pulmonary Micro Thromboembolism and Effect of Acetylsalicylic Acid Treatment
Authors: Motomiya T. , Yamazaki H.
Published: May 2019

Several reports suggest that functional and morphological changes of platelet may occur in atherosclerotic and thromboembolic diseases and acetylsalicylic acid (ASA) has been considered as one of the possibly beneficial treatments of such conditions. Thirty male rabbits including 7 pretreated with ASA 200 mg/Kg p.o. for 4 days were catheterized. ECG, respiration, arterial and central venous pressures were recorded throughout the experiment. ADP 2 mg/Kg was injected into the central vein and citrated blood was obtained before, 30 seconds, 3, 10 and 45 minutes after the injection for platelet studies. Platelet count and volume were measured using with a Coulter Counter Zbl coupled with a Channelyzer C-1000. Platelet aggregability was determined by a Sienco aggregometer. Within several seconds after completion of ADP injection the animal developed bradycardia, premature beats, ischemic ST-T wave changes, hypotension, apnea and convulsion. Histology of the lung revealed small vessels being obstructed with platelet aggregates. In rabbits received ASA developed less bradycardia and hypotension and no ischemic ST-T wave changes, apnea or convulsion. Platelet count decreased at 30-second and increased at 10-minute after injection. Significant increases in platelet volume and aggregability were noted with no overt change in platelet morphology at 3 and 10 minutes after ADP injection. Correlation between platelet volume and aggregability was significant (r=0.60, P<0.05). This experiment demonstrated that platelet size or volume is not only dependent on its age but changes transiently under certain circumstances such as thrombosis. Treatment with ASA prevented cardiorespiratory disorders and changes in platelet volume and aggregability induced by administration of ADP.
Potentiation of Heparin by Dextran and its Clinical Implication
Authors: Atik M.
Published: May 2019

The different mechanisms underlying the antithrombotic effects of heparin and dextran are known. To document the clinically suspected potentiation effect when the two agents are used together, the following study was undertaken:

In 9 patients with peripheral vascular disease, the Ivy bleeding time, the Lee-White clotting time and the platelet adhesiveness by Hellem method, were determined at control periods and at 1 and 3 hours following infusion of various doses of heparin alone. These were repeated on separate days after infusion of 500 ml of dextran in combination with same doses of heparin.

While dextran alone had no effect on the clotting time, it produced a marked and statistically significant potentiation of heparin effect (P<0.01). The mean clotting time one hour after infusion of 10,000 u of heparin was increased from 36 min. with dextran to 69 min. with dextran. This effect persisted at 3 hours. The mean clotting time after 5,000 u of heparin with dextran was almost the same as after 10,000 u of heparin with dextran. The potentiation was slight at 2.500 u of heparin. Heparin did not affect platelet adhesiveness. Dextran suppressed it when it was abnormally high, but did not reduce it below the normal value of 41 ± 9%. There was no demonstrable changes in the bleeding time by either dextran or heparin at the dosage given.

Our clinical experience and reports of other investigators suggest the desirability of the use of the two drugs in certain circumstances. To be effective and yet safe, it is recommended that whenever heparin is used in patients receiving dextran the dosage should be reduced to a half or a third of the usual.
Increased von Willebrand Factor and Defective Ristocetin-Induced platelet Aggregation in Liver Disease
Authors: Maragall S. , Ordinas A. , Clemente C. , Casals F. , Profitós J. , Castillo R.
Published: May 2019

Increased concentrations of factor VIII-related antigen(VIIIR:AG), factor VIII procoagulant activity (VIII:C) and factor VIII von Willebrand activity (VIIIR:WF) were found in plasma of patients with evidence of advanced hepatic cirrhosis. There was no correlation among the three plasmatic activities of factor VIII complex as opposed to those existing in normal individuals. The mobility of the (VIIIR:AG) as detected by crossed electrophoresis was normal.

On the other hand, washed platelets from those patients showed a defective Ristocetin-induced aggregation with normal platelet poor plasma (PPP). The platelet (VIIIR:AG) was quantitatively and qualitatively normal.
Evidence for Disseminated Intravascular Coagulation in Newborns with Streptococcal Sepsis
Authors: Sutor A.H. , Staudt F. , Pringsheim W. , Künzer W.
Published: May 2019

Neonatal sepsis with Streptococci group B has a high mortality rate. 10 of our 13 patients died within a few days. In all patients we found low platelet counts. However, only the non-survivors showed additional coagulation findings compatible with DIC (low plasma coagulation factors, low plasminogen proactivator level, increased fibrin-fibrinogen degradation products, and low granulocyte numbers). Clinical symptoms were not present until shortly before death. The diagnosis of DIC was confirmed at autopsy. The clinical course was unchanged inspite of adequate antibiotic therapy. In 3 cases therapy with heparin or exchange transfusion was unsuccesful.
Discocyte-Echinocyte Transformation in Human Platelets: Geometries of Echinocytes Prepared with Osmotic Stress and Aggregating Agents
Authors: Milton John G. , Frojmovic M.M.
Published: May 2019

Many agents cause platelets in the disc-form (discocytes) to change into spherical forms from which many pseudopods project (echinocytes). It is not known whether echinocytes prepared with different stimuli are the same. Here we investigate the geometries of echinocytes prepared with aggregating agents and osmotic stress. Geometric parameters were estimated from a cinematographic analysis of freely-rotating platelets in citrated platelet-rich plasma (PRP) under a phase contrast microscope. Echinocytes were prepared by the addition of adenosine diphosphate, thrombin or 35-50% by volume of distilled water to PRP. Under conditions of osmotic stress, 75-90% of the discocytes convert to echinocytes within five minutes followed by a slow reversion to discocytes complete within 1 - 2 hours. Main body diameters for the echinocytes, excluding consideration of the pseudopods, were in all cases 2.1 ± 0.4 um. Comparisons of the mean volume and mean surface area of the main body of the echinocyte with that of the original discocyte show that in each case echinocyte formation is accompanied by: 1) ~15% reduction in main body platelet volume, and 2) ~25% decrease in main body platelet surface area.

These results indicate that the main body geometries of echinocytes are essentially independent of the stimuli used and suggest a common pathway for echinocyte formation with

of the original discocyte surface area available for pseudopod formation.
Generation of Fibrinogen Degradation Products (FDP’s) by Neutral Proteases from Human Granulocytes and their Importance for the Blood Clotting System
Authors: Gramse M. , Bingenheimer Ch. , Egbring R. , Havemann K.
Published: May 2019

The effect of neutral proteases from human granulocytes (elastase-like and chymotrypsin-like protease) on purified human fibrinogen was investigated. Detectable by two-dimensional and Polyacrylamide electrophoresis, dependence of fibrinogen degradation of enzyme concentration and incubation time was found. Molecular weight of the FDP’s was estimated by gelchromatografy. Some greater FDP’s showed the antigenic determinants of fibrinogen and of the split products D and E. High molecular weight FDP’s inhibited fibrinogen clotting. Generated at high enzyme concentrations and longer incubation times, FDP’s lost their ability to clot themselves and to interfere with fibrin polymerization.

As these fibrinogen degradating enzymes are released by the influence of antigen-antibody-complexes and endotoxine, it can be assumed that clotting defects in patients with acute leukemia, septicemia a. o. are caused by the effects of the proteases on fibrinogen and the accumulation of FDP’s.
Alterations of Blood Coagulation in Patients with Pancreatic Disorders
Authors: Kästering H. , Hasenbein M. , Wendt C. , Lankisch P.G.
Published: May 2019

Hemorrhage as uell as thromboembolism is often found in patients uith pancreatic diseases. Ide systematically examined in the past tuo years blood coagulation factors in Ikpatients, uho uere admitted to our clinic uith elevated levels of amylases or uho were transfered from other hospitals after complications had occured.5B patients uith increased amylases (20 patients uith acute pancreatitis, 25 uith chronic relapsing pancreatitis, 2 uith concomitant pancreatitis, 11 uith pancreatic cysts) shoued no severe complications. In comparison to 26 normal persons ue found significant differences in the follouing results: enhancement of the thrombin generation in the TGT, shortening of the PTT and of the r- and k-time in the TEG, louered levels of α1-antitrypsin, α2-macroglobulin and heparin-like substances (Hiepler Test), increased levels in fibrinogen and fibrin monomere complexes, and decrease in platelets and in Quick’s Test. There uere no changes in the thrombin time, antithrombin III and plasminogen. In the group of 16 patients uith complications there uere only 3 cases of hypercoagulability, all others shoued signs of consumption-coagulopathy. The nine patients uho died all shoued signs Df acute renal failure and pancreatic lungs. Ue believe that the disturbances of blood coagulation in patients uith increased levels of amylases are initially caused by hypercoagulability and lead in some cases to thromboembolism, consumption-coagulopathy and DIC of the lungs and kidneys.
Surreptitious Warfarin Ingestion in three Nurses with Co-Existing Bleeding Disorders
Authors: Hayne O.A. , Sherman L.A. , Gaston L.W. , Fraser E.
Published: May 2019

We describe the clinical course and coagulation data of three patients surrepetitiously ingesting Warfarin. AH three patients, however, had coexisting conditions and screening coagulation tests which were initially felt to be responsible for the hemorrhagic state. All three patients were young nurses with ready access to Warfarin.

The first patient with previously documented systemic lupus erythematosis presented with hematuria and soft tissue bleeding and on the basis of screening coagulation tests was felt to have a lupus type anticoagulant.

The second nurse had disseminated intravascular coagulation and the third nurse had congenital factor V deficiency. All patients, however, had a severe depression in Vitamin K dependant coagulation factors and high levels of Warfarin were detected in the plasma of all patients. The co-existence of a disorder capable of producing hemorrhage and occult Warfarin ingestion has not been previously reported and presents a clinical diagnostic challenge.
Storage Pool Disease of Platelets in an Infant with Thrombocytopenic Absent Radii Syndrome Simulating Fanconi Anemia
Authors: Zahavi J. , Gale R. , Sacks Z.
Published: May 2019

This study reports the first example of storage pool disease, “aspirin like” variety, in a 4 month old infant with multiple congenital malformations including bilateral absent radii, thumbs and right kidney, dislocation of hip joints, equinovarus, convergent squint and hypospadias. Platelet count was decreased to 29,000/mm3 at birth and rose to 296,000/mm3 4 months later. Studies of platelet function showed a slightly prolonged bleeding time (ivy technic), decreased aggregation to collagen 0,003% and ADP 4 MM, total absence of aggregation to l-epinephrine and decreased platelet factor 4 activity. Platelet serotonin content was slightly decreased. These abnormal findings were equally detected with the father’s platelets, suggesting a genetic transmission of the platelet disorder. Platelet function of the mother, which is a first cousin of her husband, were normal. This study provides further evidence to the hereditary nature of thrombocytopenic absent radii (TAR) syndrome. The impaired platelet function seems to be an important and helpful test in the differential diagnosis of TAR syndrome and Fanconi anemia.
Morphology of Blood Platelets Exposed to pH 5.3.
Authors: Mürer E.H. , Stewart G.J. , Davenport K.
Published: May 2019

Washed human platelets incubated at 37°C in citrate buffer of pH 5.3 released most of their stored compounds slowly (t1/2 = 60 min). Addition of 2 μM NaF greatly increased the rate of release (t1/2=2 min). Exposure of platelets to pH 5.3 caused three prominent ultrastructural changes: (1) extensive formation of long, narrow channels often parallel with the plasma membrane; (2) condensation of the densely staining component (DSC) (actin?) of the cytoplasm leaving large clear areas, the whole enclosed in an apparently intact plasma membrane; and, (3) aggregation and concentration of glycogen in these clear areas. Channel formation was immediate while the other changes developed over one hour. Most platelets contained a circular mass composed of fibrillar material (DSC) with or without granules. The ultrastructure of platelets exposed to 2 μM NaF at pH 5.3 for 3 min had the characteristics of platelets exposed to pH 5.3 alone for 60 min plus the “butterfly” appearance of platelets exposed to 10 μM NaF at pH 7.4 for 15 min. Glycogen was frequently located in bulbous protrusions. Exposure of platelets to pH 5.3 may cause a slow liberation of free intracellular Ca until the level is reached which induces secretion, while NaF may act by inducing a fast and specific rise in the free Ca level. The enhanced free [Ca] may cause the condensation and centralization of DSC, which in its course may force out the glycogen particles that were previously distributed in the cytoplasm.
Quality Control of Factor VIII Concentrates Using an Automated Device. A Long-Term Study
Authors: Kirkwood T. , Miller-Andersson M. , Seghatchian M.J.
Published: May 2019

A F VIII quality control system must allow accurate and uniformly precised measurements. Accuracy depend both on assay method and on reagents. The “right answer” to a F VIII:c is undefined, so we can only control internal accuracy of the assay system by demonstrating that the result is uneffected by changes from one batch of reagent to another. Precision is affected by several sources of error,(e.g. pipetting, measurement of end point etc.) Automation allows great uniformity of these. Accuracy and precision also depend on the reference plasma. It is well established that assays of concentrate against concentrate are less variable than assays of concentrate against plasma. In this study we collected data from quality control assays of 437 batches of concentrate against frozen normal plasma (–150°C). Each assay also contained a single batch of cryoprecipitate stored under equal conditions. The assays were performed over 60 weeks during which time 6 batches of substrate plasma 2 batches of Cephotest and 7 normal plasma pools were used. The lamp used for optical determination of the end point was also changed once. Statistical analysis showed that the only major change of the results occured when the normal plasmapools were changed. Otherwise the uniformity of the measurement was very good. The results strongly suggests the use of large batches of reference standards which may be calibrated against the international standard, and is preferable to the use of frozen normal plasma pools.
An Automated one Stage Assay Technique for the Routine Evaluation of Factor VIII Concentrates
Authors: Miller-Andersson M. , Seghatchian M.J. , Kirkwood T. , Nilsson I.M.
Published: May 2019

There is a general need for a reliable automated F VIII assay system with a large capacity for block bioassays. We present a method fulfilling these requirements. A rebuilt device for APTT determinations based on an optically clear activator and an artificial F VIII deficient substrate plasma has been used continously for 2 years. The substitution of hemophilia plasma by an artificial substrate plasma is a necessary feature for any satisfactory large scale automated system. There was no evidence of any differences between results obtained using this substrate and congenital deficient plasma. The reproducibility of the assay system was very good.(S.D. ≈ 10 %). And the results obtained by two different machines where indistingquish-able. The results showed very good agreement between the relative potency estimates of known F VIII standards obtained with this method and those found at recent international collaborative studies. However, comparison of assay results of clinical F VIII preparations with estimates of in vivo recovery shows that this method estimates lower potency of the given concentrates. These finding is in accordance with several other studies, that has shown that different assay methods detect relatively differing activities in preparations of different purity. Since it is important that the labeled unitage of the clinical material should continue to produce the same measured in vivo recovery at the “Reference Hemophilia Centre” (Malmö, Sweden), we have calculated simple convertion factors to apply to the assay results eliminating the appearent différencies.
Procoagulant Activity of Thrombosthenln Preparations
Authors: Muszbek L. , Fésüs L. , Szabó T. , Harsfalyi J.
Published: May 2019

3 x precipitated bovine thrombosthenin preparation exerted a powerful pro-coagulant effect similar to platelet factor 3 activity. In the presence of thrombosthenin the recalcification time, the kaolin clotting time and the Stypven tine considerably shortened, the partial thromboplastin time only slightly altered and the activated partial thromboplastin time did not change at all. Thrombosthenin highly accelerated the generation of intrinsic thromboplastin but it was not active in a factor IXa generation test. It neither possessed tissue factor like property nor influenced the activity of tissue factor preparation or the action of thrombin on purified fibrinogen. Thrombosthenin contained 109 μg phospholipid/mg protein, the composition of which was quantitatively determined by thin layer chromatography. The procoagulant activity as well as the phospholipid content were retained after agarose gel filtration. It is suggested that thrombosthenin having an associated phospholipid component significantly contributes to the clot promoting effect of activated platalets.
Studies on the Effects of Smoking on Vmous Thromboembolic Disease
Authors: Pollock Andrew , Lewis M.J. , Mistry D.K.
Published: May 2019

It has been suggested that smoking protects against the development of deep vein thrombosis following myocardial infarction, although large studies on the effects of smoking have generally failed to show any association with venous thromboembolic disease.

In a preliminary survey of patients attending an anticoagulant clinic, fewer male smokers, and more female smokers than expected, were attending after a deep vein thrombosis. Further analysis of these results, suggested that they were due, at least in part, to factors other than smoking, and a larger study was undertaken to compare the incidence of smoking in patients who had had a deep vein thrombosis, with that in the hospital outpatient population as a whole. No differences in smoking habits were found “between these groups, but small differences were observed between various groups of patients with venous thromboembolism, e.g. myocardial infarction was listed as a predisposing cause, more often than expected in male non-smokers.

Thus, while smoking may effect the development of deep vein thrombosis in particular situations, e.g. after myocardial infarction, this study has failed to show any significant influence on venous thrombosis in general.