bluuebunny/crossref_metadata_2025 huggingface dataset:
The Diagnosis Of Pulmonary Embolism: The Diagnostic Dilemma Of Ventilation-Perfusion Lung Scanning
Authors: Hull R , Sackett D L , Hirsh J
Published: July 2018

After a promising introduction, many diagnostic tests prove with further experience to be very limited in their clinical application. There are two major reasons for inappropriate application of diagnostic tests. Firstly, the evidence for their clinical value is based on basic or experimental studies, the findings of which have been incorrectly equated with hard evidence for their clinical efficacy. Secondly, studies evaluating diagnostic efficacy have frequently failed to include essential design features which are required to adequately assess the sensitivity, specificity and predictive values of the test under evaluation. The diagnostic dilemma of ventilationperfusion lung scanning is a classic example of the failure to adequately assess a diagnostic test. The diagnostic efficacy of ventilation-perfusion lung scanning is currently uncertain and highly controversial because none of the published studies have adequately evaluated this non-invasive approach. To resolve this uncertainty, we have incorporated the six essential criteria for evaluating diagnostic efficacy in a prospective study of ventilation-perfusion lung scanning and pulmonary angiography. These essential criteria are: comparison with pulmonary angiography, the reference test in consecutive patients; entering a broad spectrum of patients with suspected pulmonary embolism; including a large number of patients with varying clinical severity of illness and disease; and patients with a wide variety of co-morbid conditions; avoiding diagnostic suspicion bias by evaluating consecutive patients and by interpreting the test results independently without knowledge of each other or the patient’s condition; and finally testing the clinical validity of negative results by long-term follow-up. The effect of these criteria on the outcome of this trial will be presented.
Incidence Of Venous Thrombosis, Increased Platelet Release Reaction And Thromboxane Synthesis Following Tourniquet Ischaemia
Authors: Zahavi J , Price A J , Westwick J , Kakkar V V
Published: July 2018

Deep vein thrombosis (DVT) was established by ascending phlebography in 121 meniscectomy (M) (mean age 34 years) and 27 total knee replacement (TKR) (mean age 62.9 years) patients, both procedures performed under ischaemia (by inflating a pneumatic tourniquet to 500 mm Hg). In 27 of the M, 10 TKR and another 10 patients undergoing herniorrhaphy (H) and served as controls plasma β-thromboglobu- lin (βTG) was measured by radioimmunoassay and in 22 M and 10 TKR patients plasma thromboxane B2 (TxB2) was also determined. The incidence of DVT was 29% in the M patients. It increased significantly with age reaching a level of 50% at 60 years. In the TKR group 49% developed DVT. There was also a positive correlation between the severity of of DVT and patient age in both groups. The mean plasma βTG and TxB2, rose sharply (p<0.001) 5 min after the release of the tourniquet and were positively correlated to each other. The high level returned to the pre-operative level after 48 hours. In the H patients βTG did not alter significantly pos toperatively

The high incidence of DVT in the relatively young patients who underwent M (minor surgical trauma similar to that of H) reaching the incidence of TKR patients (major surgical trauma) at 60 years, suggests that tourniquet ischaemia may be an important factor in the development of venous thrombosis in these patients. The increased in-vivo platelet activation and thromboxane synthesis, indicated by the increased plasma βTG and TxB2 levels, which was not detected in the H patients, suggests that platelets may play an important role in the initiation of the DVT in tourniquet ischaemia patients.
Modulation Of PGI2-Like Activity Of Human Endothelial Cells By An Extracellular Collagen Matrix
Authors: Spiegel K M , Mohammad S F , Chuang H Y K , Mason R G
Published: July 2018

Human umbilical vein endothelial cells were grown on several artificial matrices including collagen and on unmodified plastic dishes. Freeze thaw preparations of confluent monolayer endothelial cell cultures were assayed for PGI2-like activity by testing for inhibition of platelet a88regation. The cells grown on a collagen matrix expressed slightly less PGI2-like activity initially compared to the cells grown on plastic. When the PGI2like activity of the cell lysates was examined over a period of three hours after the initial preparation, endothelial cells grown on a collagen matrix exhibited a more rapid loss of activity. Preliminary quantitative evaluations suggest that lysates derived from cells grown on unmodified plastic retained 75% PGI2 like activity at 15 min, at which point collagen grown cells exhibited essentially no PGI2-like activity. Furthermore, as shown in the figure, under identical experimental conditions, cell lysates obtained from endothelial cells grown on unmodified plastic continued to express approximately 50% of the initial PGI2-like activity after one hour. Since addition of purified PGI2 or cell lysates in vitro to the collagen coating used as tissue culture substrate failed to cause any significant loss of platelet aggregation inhibitory activity beyond the normal rate of decay of PGI2 it appears likely that the reduction of PGI2-like activity may be associated with changes in the substrate collagen, possibly effected by the endothelial cell layer. Alternatively, the reduction of activity may be related to differences in the endothelial cells caused by growth on the collagen substrate.
Shortlasting Effects Of Acetylsalicylic Acid (ASA) And Dipyridamole On Spontaneous And Tissue Extract Induced Platelet Stimulation And On Platelet Retention
Authors: Breddin K , Kirchmaier C M , Trautmann K O , Sehrbrock M , Reinfelder G
Published: July 2018

30 healthy individuals received single doses of 250,500 or 1000 mg ASA (Aspirin), 10 persons took 750 mg of an ASA preparation with retarded intestinal absorption.24 volunteers received 75 or 150 mg dipyridamole alone or together with 500 mg ASA.

Spontaneous and tissue extract induced platelet stimulation were investigated using interference contrast microscopy. Collagen induced aggregation (1µg/mlPRP) was measured 30 - 45 minutes after blood sampling. Platelet retention was investigated using a modified Hellem test.

Platelet stimulation and retention were inhibited for 8 - 10 hours after the intake of ASA. The higher doses had a more pronounced and longer lasting effect. The effect of 750 mg of the slowly absorbed form of ASA lasted longer than that of 1000 mg Aspirin. Platelet retention was inhibited in a similar way as platelet stimulation. No correlation between the long lasting inhibition of platelet aggregation and the shortlasting effects of ASA on platelet retention and platelet stimulation was found.

It has to be established to which extent the shortlasting effects of ASA and Dipyridamole are essential for the antithrombotic effect of both drugs. If these effects are contributing to the antithrombotic effect of ASA, differences in the results of similar clinical trials as the AMIS and PARIS studies on patients with recent myocardial infarction could be explained by different dose regimens in these studies, e.g.the use of 2 × 500 against 3 × 330 mg ASA.
The Activity Of PhthalazinoL In Basic Platelet Function Tests
Authors: Saunders R N , Smith S L , Nicholson N S
Published: July 2018

Phthalazinol (EG-626, SC-32840) was evaluated in several basic platelet function tests in comparison with known antiplatelet agents. The IC50șs for collagen-, ADP-, and thrombin-induced aggregation of human platelets in vitro were 28, 51 and 88 µM, respectively. Phthalazinol (100 µM) did not alter the cAMP levels of rat platelets in vitro in either the presence or absence of PGE1. When administered orally to retired breeder rats, Phthalazinol prevented the formation of platelet aggregates as determined by the Wu and Hoak technique with ED50’s of 5.5 and 18.7 mpk, i.g. at 3 and 24 hours, respectively, post injection. Phthalazinol did not alter the platelet serotonin content in rats even when administered at 100 mg/kg orally for three days. In an ex vivo disaggregation assay, arterial blood from anesthetized cats was perfused over rabbit tendon strips and recirculated to the cat. The resulting platelet build-up (200-400 mg) was significantly (p < .001) reversed (67% loss) by the i.v. infusion of Phthalazinol at 15 mg/kg. Phthalazinol has demonstrated positive effects in several platelet evaluation models and is a potentially unique antithrombotic agent.
Lu 23051, A New Potent Inhibitor Of Platelet Aggregation
Authors: Lehmann H D , Gries J , Lenke D
Published: July 2018

6- [p-(2-(Chiorpropionylamino)phenyl] -4.5-dihydro-5-methyl-3(2H)-pyridazinone, LU 23051, is primarily characterized by its strong inhibition of platelet aggregation under in vitro and in vivo conditions. In vitro there is a concentration-dependent inhibition of ADP and collagen induced aggregation in platelet rich plasma of man, rat and dog. The inhibitory concentration EC 33 % is 0.0010-0.030 mg/1 (man: ADP-0.030, col 1.-0.013 mg/l) depending on species and type of aggregation. When administered orally in ex vivo experiments on rats and dogs the substance is found to have a dose-dependent antiaggregatory effect in the range from 0.1-3.16 mg/kg. The ED 33 % is 0.27-0.63 mg/kg.-In addition after oral administration the substance has a good inhibitory effect in models being based on intravascular platelet aggregation. Thus, a dose of 1 mg/kg inhibits laser-induced aggregation in mesenteric venules of rats. Mortality after i.v. injection of collagen in mice is reduced by 50 % after a dose of 0.02 mg/kg. A dose of 0.039 mg/kg prolongs the bleeding time of rats by 50 %. The aggregation-inhibiting action is of long duration (0.1 mg/kg p.o.∼24 h). The substance does not interfere with clotting.

Besides its effect on platelet aggregation LU 23051 acts as vasodilatator as well. Dilatation of coronary vessels by 100 % is seen in isolated guinea-pig hearts at a concentration of 0.1 mg/l. In spontaneously hypertensive rats the substance has an anti hypertensive effect. The ED 20 % is 0.36 mg/kg p.o.

The combination of antiaggregatory and vasodilatatory effects opens up interesting aspects with respect to the pharmacotherapeutic use of the new substance
Effect Of Solvents On Indium-111 Oxine Transport In Human Platelets And On Platelet Function In Vitro
Authors: Tsukada T
Published: July 2018

Mechanism of Indium-111 oxine(In) transport in human platelets in buffered saline and the effect of In-labeling on platelet function were studied using In dissolved in 25% of ethanol in saline (In-ES) or 0.01% of polysorbate 80 in HEPES buffer(In-PH). Increase in temperature up to 37° C progressively enhanced the transport of In-ES, while transport of In-PH reached to plateau at 15°C. A states of equilibrium was not reached during 2 hr incubation at 22°C in In-ES. Uptake of In-PH reached to plateau after only 15 min of incubation. Distribution of In taken up by platelets in InES was 57% in cytosol and 27% in stroma, while in In-PH 69% in stroma and 22% in cytosol. 88% of In in cytosol was bound to lipids(46% in cholesterol and 27% in PS+PI). 82% of In in stroma was found in PS+PI fraction.

The fact that the ratio of free In between the platelet water space and the outside medium after 30 min of incubation at up to 0.1 uM of In exceeded unity, suggests satura- , ble component of In transport prevails at this concentration in In-ES and In-PH. Kinetic constant could be calculated, Kt= 2nM, Vmax= 2.5 pmol/min/ml in In-ES, and Kt= InM, Vmax=0.7 pmol/min/ml in In-PH.

Elution of In from radiolableled platelets in autologous plasma incubated at 37°C for 5 hr was less than 10% in the case of In-ES and 56% in the case of In-PH. Less than 3% of labeled-In was eluated from platelets in collagen-induced aggregation and 4-7% of In was eluated in thrombin-induced aggregation.

Although 0.3% of ethanol and/or 6nM of oxine have no inhibitory effect of platelet aggregation, collagen-induced aggregation and release reaction of In-labeled platelet was impaired. 0.003% of polysorbate 80 itself abolished completely the aggregability of platelets by collagen or thrombin.

It is concluded In-PH is unsuitable for platelet labeling. In-111 oxine also seems to have problems which Cr-51 has, i.e. inhomogenous distribution of In in a platelet population, elution of In from labeled platelets in circulation.
Distribution Of Indium-111 In Labeled Human Platelets: Implications In Platelet Survival And Dosimetry
Authors: Dewanjee M K , Rao S A , Didisheim P
Published: July 2018

Subcellular distribution of In-111 in In-111-labeled platelets (In-P1) determines the biodistribution and dosimetry of In-111 after the in vivo lysis of In-P1. Human platelets were labeled with In-111-oxine (In-Ox) and In- 111-troPolone (In-TPL) in ACD/saline (A/S) and plasma (P). In-P1 was lysed after 6 repeated freezing and thawing procedures. A fraction of In-P1-lysate (In-P1-LS) was filtered (0.22 ym) and passed through a calibrated Sephadex G-100 column for estimation of molecular weight (Mol. wt.) of In-bound Pl-protein. The In-P1-LS was injected in 15 rabbits and biodistribution (% I.D.) performed at 24 hours after I.V. administration. Results are tabulated below: 80 ± 11% and 70 ± 10% of In was bound to soluble platelet protein when platelets were labeled in plasma and A/S respectively. Mol. wt. of In-bound platelet protein was estimated as 52,000 ± 5,000 daltons. Biodistribution shows that In-PI-LS labeled in A/S localizes more in RES than plasma; whole body retention is also longer. These studies shed further light on the binding sites of In in platelets labeled in A/S or plasma media and their ultimate fate after administration
Fibrinogen Induces Changes In Platelet Membrane Potential
Authors: Vainer H , Caprani A
Published: July 2018

Changes in platelet membrane potential (MP) reflecting ion transmembrane transport accompany the platelet activation by various stimuli. We have studied the platelet MP and the effect of fibrinogen on its expression, using an electro-chemical method. The MP determination is based on the evaluation of the transmembrane partition coefficient (PC) (Ci/Ce) of an electroactive tracer, such as the ferro- cyanid anion. Washed human platelets are incubated with the tracer solution ; the amount of tracer in the supernatant (Ce) and in the acellular lysate of SDS-treated platelet pellet (Ci) is measured as the diffusion limiting current corresponding to the tracer oxidation at the surface of a rotating disc electrode. The kinetics for the PC evaluation have been studied in order to standardize the experimental conditions which allow to express the MP by the Nernst equation : Vi-Ve = RT/4F. Log Ci/Ce.

The mean value ± SD (N = 9) of the platelet MP in saline is -5.5 ± 0.5 mV (PC = 0.445 ± 0.020). When fibrinogen replaces the saline, a MP of -8.83 mV (PC = 0.257) is observed. While it contrasts sharply with the MP of platelets in saline, it is comparable to the MP of platelets in plasma, which is : -8.63 mV (PC=0.266). We have also measured the effect of human albumin and gamma globulins on the MP ; both these plasmatic proteins cause a much smaller decrease of MP, as compared to fibrinogen (or plasma), all used at physiological concentrations in saline and without the platelet pretreatment with any agent.

The results suggest that a relationship might exist between the marked decrease of platelet MP caused by fibrinogen - possibly via mediators of the transmembrane transport- and/or some of the platelet membrane glycoproteins which appear to function as binding sites for fibrinogen and must undergo (conformational) changes that allow fibrinogen to bind.
Comparison Op Fibrinogen Binding To Pig Intact Platelets And Their Membranes
Authors: Cierniewski C S , Krajewski T , Janiak A
Published: July 2018

In order to explain the precise role of fibrinogen in ADP dependent aggregation of platelets, purification of the presumed platelet fibrinogen receptors is required. We, therefore, compared binding of fibrinogen to the intact platelets and their membranes. Fibrinogen, free of plasminogen and vitamin K-dependent factors, was radiolabelled and used as the probe for a receptor in the platelets membranes. Platelet membranes isolated according to Barber and Jamieson /1970/ were used in the binding assay as a suspension in 0.025 N Tris-HCl buffer, pH 7.4, containing 0.14 M NaCl and 0.66 % polyethylene glycol. The binding specificity was determined by test in which cold fibrinogen completely inhibited binding of the io- dinated fibrinogen, whereas other proteins did not. The pattern of fibrinogen binding was characteristic for a saturable receptor. Scatchard analysis of the binding indicated a single class of receptors, with an estimated association constant of 5 × 108M-1 comparable to that estimated for fibrinogen binding to the intact pig platelets. In contrast to the intact platelets, binding of fibrinogen was not dependent upon the ADP stimulation. We conclude that a specific receptor for fibrinogen is exposed on the surface as a result of cell damage which is the first step of platelet membrane isolation procedure.
The isolated membranes retain binding properties of the intact platelets and may serve as a source for the isolation of fibrinogen receptors.
Circulating Platelet Aggregates In Thrombotic Pathologies
Authors: Rodzynek J J , Schoenfeld P L , Martin T , Léautaud P , Wettendorff P , Delcourt A
Published: July 2018

The dosage of circulating platelet aggregates following Wu and Hoak (CPA) was performed in 52 healthy volunteers acting as normal controls (N), in 205 consecutive patients admitted in a general hospital for pathologies other than thrombotic or cardiac ischaemia (group I), in 59 consecutive admissions for deep venous thrombosis (group II), in 45 consecutive admissions for pulmonary thromboembolism (group III), in 35 consecutive admissions for acute coronary insufficiency (group IV) and in 73 consecutive admissions for acute myocardial infarction demonstrated by electrocardiogram and specific enzymes (group V). The percentage of positive tests (CPA 0.80) in those various groups appeared as follows: In conclusion: The positivity of CPA is not a specific indicator of a thrombotic disease neither of acute coronary insufficiency (36.5% false positive tests). CPA is not sensitive for the diagnosis of thrombotic conditions.

In the setting of ischaemic heart disease, CPA positivity appears with higher frequency when myocardial necrosis is demonstrated, However the two groups don’t differ significantly on a statistical basis (P non significant).
Platelet Adhesion And Aggregation In Behcet’S Syndrome
Authors: Brook J G , Aviram M , Haim S , Markel A , Weiner A , Marmur A , Berkowits Y , Bornstein I , Youdim M
Published: July 2018

Both venous and arterial thrombosis can be a feature in some patients with Behcet’s Syndrome. The pathogenesis of the coagulopathy is as yet ill understood. We have examined platelet adhesion and platelet aggregation in 14 patients with proven Behcet’s Syndrome and compared them with matched controls. Platelet adhesion was measured by two techniques recently developed in our laboratory. In the first platelet adhesion is determined when platelet rich plasma is applied to a glass slide while applying a predefined centrifugal force. In the second method citrated whole blood is pumped through an inert silicone tube and applied to a glass slide in the form of a stagnation point flow field. The number of platelets adhering to the slide per unit area is determined. The conditions of blood flow through this system were similar to those prevailing in arteries of similar size. Adhesion is found to be significantly greater in Behcet’s patients by both methods. There was a 30% increase in platelet adhesion in the Behcet patients. Platelet aggregation was determined by the Born method. Platelet rich plasma was used and 5HT, epinephrine, ADP, and collagen were the aggregating agents. In our hands platelets from the Behcet’s patients are more sensitive to aggregation induced by epinephrine and ADP than platelets from our controls.

It appears that disturbed platelet function may play an important role in the coagulopathy of Behcet’s Syndrome.
Platelet Norepinephrine Fluxes In Normotensive Subjects And Essential Hypertensive Patients
Authors: Legrand C , Dubernard V , Meyer P
Published: July 2018

Disturbed neuronal metabolism and storage of monoamines has been described in various experimental and human hypertensive diseases. Since blood platelets are considered as valid models of sympathetic neurons, the uptake and release of [3H] norepinephrine (NE) was investigated in platelets isolated from normal subjects and from patients having essential hypertension. In addition, the intracellular metabolism of [3H] -NE was followed by high performance liquid chromatography.

In basal conditions, NE was found to be slowly incorporated into the platelets and approximately 25% of the absorbed radioactivity was recovered as a sulfoconjugate metabolite which is thought to represent the cytoplasmic form of the monoamine. The uptake of NE was inhibited by drugs known to interfere with the platelet serotonin accumulation at the plasma membrane level (chlorimipramine, ouabain) or at the vesicular storage level (tyramine, reserpine). In addition, drugs which impair the intravesicular storage of monoamines leading to their accumulation in the cytoplasm, induced a marked increase in platelet NE metabolism and release.

The uptake of norepinephrine was slightly reduced in platelets from essential hypertensive patients. A marked increase in spontaneous NE release was measured in correlation with increased intracellular NE metabolism. The results are compatible with impaired intravesicular storage of the monoamine leading to increased diffusion through the plasma membrane.
Interaction Of Platelets And Tumor Cells: Differentiation Between Nine Human Tumor Cell Lines Based On Aggregation And Effects Of Apyrase, Hirudin And Phospholipase D
Authors: Jamieson G A , Bastida Eva , Ordinas Antonio
Published: July 2018

Aggregation mechanisms have been examined in a homologous system using heparinized human platelet-rich plasma with cell lines derived from human tumors. The A549 (epithelial lung carcinoma) and Hut23 (adenocarcinoma) did not aggregate platelets at 107 cells/ml. Other cell lines could not be classified by aggregation pattern alone since all gave biphasic or quasibiphasic patterns. HT 29 (adenocarcinoma) , SKBR3 (adenocarcinoma), HT 144 (melanoma) and Hut 20 (large cell lung carcinoma) were inhibited by apyrase and phospholipase D but not by hirudin: aggregation induced by this group is probably primarily dependent on ADP. Aggregation by SKNMC (mesothelioma) and Hut 28 (mesothelioma) was inhibited by hirudin and phospholipase D but not by apyrase. Aggregation by this second group probably involves activation of the clotting system in the early stages but can be differentiated from a similar mechanism with U87MG since thq latter is not inhibited by phospholipase D. Phospholipase C had no effect on any cell line and phospholipase A2 inhibited all cell lines, as did its hydrolytic product, lysolecthin. Platelet aggregating material (PAM) could not be isolated by urea extraction of any of these human tumor cells. These results suggest that various inhibitors are necessary to allow classification of mechanisms of tumor cell-induced platelet aggregation.
Circulating “Empty” Platelets In Hemolytic Uremic Syndrome And Thrombotic Thrombocytopenic Purpura
Authors: Lüchters G , Budde U , Klehr U , Müller N
Published: July 2018

In two patients (1 male, 1 female) the diagnosis of hemolytic uremic syndrome (HUS) and in one male patient the diagnosis of thrombotic thrombocytopenic purpura (TTP) was confirmed. All patients showed a platelet aggregating factor in plasma. PgI2-stimulating activity of patient’s plasma was defective or absent. Platelet count was low and platelet aggregation was severely impaired. Even with high amounts of ADP (20 μM) only first phase aggregation could be seen. Epinephrine induced aggregation was absent. The highest amount of collagen used (20 μg/ml) induced only a small aggregation and no ATP-secretion. Thrombin stimulated ATP-secretion was decreased while Ristocetin induced aggregation was normal. ATP- and ADP-content of platelets was low and ATP/ADP ratio was raised above the normal value. Platelet spreading was severely impaired.

From these findings we conclude that at least part of the platelets in these related diseases are circulating “empty” platelets which underwent degranulation in the patient’s blood vessels.
Beta - ThrombogloBulin And HA - Platelet Factor 4 In Multiple Myeloma, Hodgkin Disease And Malig - Nant Lymphoma - Effects Of Therapy
Authors: Klingemann H G , Eqbrinq R , Havemann K
Published: July 2018

Determination of platelet specific proteins Beta-Thromboglobulin ( β-TG) and High Affinity Platelet Factor 4 (PF 4) in plasma has been proved as useful marker for an enhanced release reaction in some diseases, mostly due to an in - creased platelet aggregation. To evaluate suit - able marker for a prethrombotic state in some myeloproliferative diseases ue investigated patients suffering from multiple myeloma, Hodgkin disease and malignant lymphoma. β- TG and PF 4 were measured in platelet poor plasma using RIA - kits (Amersham-Buchler / Abbott Labor.). In addition ue determined; platelet count, spontaneous and collagen induced platelet aggregation, the activity of AT III and of the clotting factors I, V, VIII, XIII and the concentration of FDP.

RESULTS: Normal range was found to be 0-55 ng/ml forβ-TG and 0-12 ng/ml for PF 4. Both release proteins were increased in 17 out of 25 patients with myeloma, in 13 out of 15 patients with Hodgkin disease and in 10 out of 12 patients with malignant lymphoma. A correlation to the severity of the diseases were demonstrable. Chemotherapy caused a decrease of β -TG and PF 4 levels in some cases. However no correlation could be found between β- TG and PF 4 levels and in vitro tests of platelet aggregation. Further clotting assay provided evidence for an activation of clotting (like DIC) in a few patients. Other possibilities - like the release of the platelet specific proteins by immunocomplexes, prostaglandins or proteolytic enzymes from granulocytes must taken into account.
A Radioimmunoassay For The Quantitation Of Bovine Platelet Factor 4 And Its Use In Monitoring Artificial Heart Implants
Authors: Clark D M , Deneris J , Workman E F , Olsen D
Published: July 2018

A radioimmunoassay for the quantitation of bovine platelet factor 4 (PF4) has been developed for use on bovine plasma. The assay utilizes classical radioimmunoassay techniques; 50λ of standard or plasma are mixed with 250λ 125I- bovine PF4 and 250λ goat anti-bovine PF4 for two hours at room temperature. Antibody-bound PF4 is separated from free PF4 by precipitation with ammonium sulfate. The resulting standard curve has a least detectable dose of 50 ng/ml, a 50% intercept around 400 ng/ml, a range of 01000 ng/ml and is unaffected by the presence of heparin in samples. Plasma samples are collected using a two-Vacu- tainer technique employing Thrombotect™ collection tubes (Abbott Laboratories) which have been developed to minimize any in vitro platelet release. The mean PF4 concentration of 7 healthy control calves was 55 ng/ml with a range of 0 to 180 ng/ml. PF4 levels were measured serially in calves which had undergone artificial heart implantation.

In one calf with a pre-operative PF4 level of 99 ng/ml, the PF4 level increased to 638 ng/ml during post-surgical complications 7 days after surgery and subsequently decreased to 230 ng/ml after coumarin therapy 27 days after surgery. A similarly implanted calf without post-surgical complications had a pre-operative PF4 level of 180 ng/ml and a 20 day post-surgical level of 245 ng/ml. These data suggest that PF4 levels are elevated in post-surgical hypercoaguable states and that measuring PF4 provides a useful tool for monitoring the post-surgical patency of artificial surfaces such as prosthetic valves, artificial hearts, left ventricular assists and thoracic surgery in general. This program is under further investigation to increase the understanding of platelet involvement in such systems, to determine how long PF4 elevations exist prior tc the.onset of clinical symptoms and to follow the success or failure of anticoagulant therapies.
Modification Of The Haemostatic System By Atherogenic Diets In Rats
Authors: Badimon J J , Badimon L , Villaverde C A
Published: July 2018

We have studied the haemostatic system and its modification due to different atherogenic diets in Sprague-Dawley rats. The diets administrated were an original previous ly described atherogenic model and its two constituent phases; a first phase of 3 days (hypervitaminic-D2) that produced calcic infiltration followed by a second one of 12 days (hyperlipidic) that induced lipid deposition.

The hypervitaminic diet induced a highly significant (2p< 0.001) increase on triglycerides (TGL); the total-CHO/ HDL-CHO ratio decreased slightly. It induced a highly increase of the index of thrombodynamic potential (ITP) with out modification of fibrinolytic activity and fibrinolytic inhibitors.

The hyperlipidic diet induced a highly significant increase (2p<0.001) of TGL, CHO and VLDL. The total-CHO/ HDL-CHO ratio decreased markedly (2p <0.001). This diet by itself did not produced vascular morphological lesions. It was obtained a slight increase in the ITP, a significant de crease in fibrinolytic activity of whole blood without modT fication of diluted blood fibrinolytic activity and an increase in the level of fibrinolytic inhibitors.

The experimental model, arranged by the two phases consecutively given, induced a highly (2p<0.001) increase of CHO, TGL and VLDL. The total-CHO/HDL-CHO ratio decreased markedly (2p <0.001). The ITP was also increased; fibrinolytic activity of whole blood was diminished without modifica tion of diluted blood and fibrinolytic inhibitors were increased.

Thus, this experimental model induced an atheroscle- ritic pattern with activation of the coagulation system, due to the hypervitaminic phase, and decrease of fibrinolytic activity and increase of fibrinolytic inhibition, due to the hyperlipidic phase.
Erythrocyte Adherence To Endothelium In Diabetes Mellitus. Relation To Vascular Complications
Authors: Wautier J L , Paton R C , Wautier M P , Passa P , Caen J P
Published: July 2018

Diabetes mellitus is associated with an increased tendency to thrombotic diseases. Contributing factors may include red cell abnormalities. The adhesion of erythrocytes from 29 diabetics and 18 controls to endothelial cells was studied. Washed erythrocytes were labelled with 51Cr and added to confluent endothelial cells cultured from umbilical veins in 35 mm Petri dishes. After 30 min incubation at 37°C, the non adherent erythrocytes were removed by sequential washings. The percentage of erythrocytes adhering to cultured endothelium after each wash was significantly increased in diabetics compared to controls (p 0.005). After the fifth wash the mean adherence ratio (% of adhering diabetic RBC/2i adhering control RBC) was 2.32 (range 0.8 - 5.2). Increased adhesion was related to the extent of vascular complications in the diabetics as assessed by a vascular score adjusted for age and not to age or duration of diabetes. These results suggest that abnormal interactions between erythrocytes and endothelium may be one factor contributing to vascular disease in diabetes.
In Vitro Tests Fail To Predict The Increased Risk For Ara-Chidonate-Induced Thromboembolism In Rats On Oral Contraceptive (OC) Treatment
Authors: Roncaqlioni M C , Bertelé V , Minno Di G , Pangrazzi J , Donati M B , de Gaetano G
Published: July 2018

Much effort is at present devoted to the search for laboratory tests to predict thromboembolic complications. In this context we have selected OC-treated rats as an experimental model to evaluate whether increased in vivo susceptibility to a thrombotic challenge (sodium arachidonate, NaAA) could be detected by appropriate in vitro tests. Female CD-COBS rats were treated for 10 estral cycles (about 40 days) with an oral combination of lynestrenol (10 mg/kg b.w.) and mestranol (0.3 mg/kg b.w.) dissolved in com oil. Control rats received the vehicle only. After i.v. infusion of NaAA (110 mg/kg b.w.) only 2 out of 24 control rats died within 2 min. Despite the relative resistance of this species to NaAA 10 of the 23 OC-treated rats did not survive NaAA infusion (p = 0.006 compared to controls). Rats made severely thrombocytopenic (less than 2.104 platelets/ul) by a specific antiplatelet antiserum or given aspirin (100 mg/kg b.w.) 1 hour before injection were significantly protected from death following NaAA infusion (p˂0.005) . This indicates that the lethal effect of NaAA involved platelet cyclooxygenase. In vitro experiments however shewed that platelet thromboxane B2 generated with various concentrations of NaAA(0.25- 1 mM) was not significantly different in OC-treated and control rats. Moreover, the minimal concentration of NaAA inducing maximal platelet aggregation was 2.1”0.2 mM in controls and 2.6”0.4 mM in treated rats (p˃0.05) . PGI2 antiaggregating activity generated by aortic specimens incubated with 25 uM NaAA was also similar in both groups. In conclusion, in vitro tests exploring platelet or vascular susceptibility to NaAA failed to identify OC-treated rats as a group at risk for NaAA-induced thromboembolism.
Hemostatic Variables In A Group Of Traffic Police Men
Authors: Mandalaki T , Hatzakis A , Louizou C , Antonopoulou A , Vergi M , Polichronakis E , Trichopoulos D
Published: July 2018

A study of various haemostasis parameters in a group of twenty-two traffic policemen working under special conditions, i.e. in locations of heavy traffic (5 hours shifts in the centre of Athens) is presented. These normal subjects (aged 22-39) are subjected to physical and psychological stress and to the effect of increased air pollution. Pretests were conducted before the beginning of the shift (6 a.m.) and postests were conducted at the end of the shift (12 noon).

The following tests were performed: 1. Prothrombin Time (P.T.), 2. Activated Partial Thromboplastin Time (A.P.T.T.), 3. Fibrinogen, 4. Euglobulin Lysis Time (E.L.T.), 5. Fibrin Degradation Products (F.D.P.), 6. Platelets, 7. Platelet Aggregation by A.D.P., 8. PF4 9. F VIII:C, F VIII:Ag, F VIII:Rcof, 10. Antithrombin III (AT III).

Results: Significant decrease of Fibrinogen, ELT and AT III, significant increase in APTT, FDP. Increase in PF4 levels. The results are indicative of the occurence of an activation of the fibrinolytic mechanism after the shift with signs of consumption of certain coagulation factors. There is an adverse effect on the hemostatic balance of traffic policemen during their service.
Influence Of Yoga Or Blood Coagulation
Authors: Chohan I S , Nayar H S , Thomas P , Geetha N S
Published: July 2018

Yoga,an ancient Indian cult,is knovn to endow one with perfect physical,mental and spiritual health. Its effect on blood coagulation is not known. A pilot study was conducted, Seven adult males underwent a combination of yogic exercises, daily one hour,for 4 months. Parameters of blood coagulation were estimated before commencement of yoga and then repeated at the end of training. These included: haemoglobin(Hb) gm/dl,haematocrit (Hct), blood platelet counts in thousands/cu mm, activated partial thromboplastin time(APTT) sec, platelet aggregation time(FAT) sec, fibrinogen mg/dl, and euglobulin fibrinolytic activityfFA) measured as area of lysis in sq mm. Final results were compared with the initial ones. All values are expressed as Mean ± SEM.

Following yoga, Hb Showed a significant rise from 13.5 ±;, 0.1 to 14.5 ± 0.3 and so did Hct from 44.5 ± 1.1 to 49.3 ± 1.2. FA increased significantly from 271 ± 36 to 443 ± 6 4, it was accompanied by a fall in fibrinogen from 2 54± 17 to 202 ± 10. APTT prolonged from 16.4 ± 0.2 to 17.4 ± 0.7 and so did PAT from 3 3 .O ± 3 .? to 40.1 ± 9.75 though differences here were not significant. Blood platelet counts showed a marginal but significant rise from 336.6 ± 26.3 to 391.6 ± 10.0.

This study suggests that yoga induces a state of hypocoagulability evident by raised FA,fall in fibrinogen,suppressed platelet activity and low levels of activated clotting factors. Yogic exercises,therefore,may be instituted for prevention of cardiovascular and thrombotic disorders in man. Benefits of yoga seem to accrue from oarasympathodominance and symnathetic quiescence of the autonomic nervous system brought about by yoga.
Uraemic Bleeding : Contributory Role Of Red Cells
Authors: Livio M , Marchesi D , Mecca G , Remuzzi G , Donati M B , de Gaetano G
Published: July 2018

The bleeding times (B.T.) of 65 patients with chronic uraemia were determined inmediately before a routine haonodialysis session. A significant negative correlation (r=0.67, p < 0.01) was found between B.T. and packed cell volume (PCV) values. When the patients with bleeding times longer than 15 min were excluded frcm the analysis, a negative correlation with PCV was still apparent (r = 0.55; p<0.01 ) .in addition, X2 analysis showed a significant association between PCV values <30% and B.T. longer than 260 sec(p<0.001) . Fourteen uraemic patients with PC/ values between 13% and 27% and B.T. longer than 15 min, required washed blood cell transfusions, after which PCV values increased variably but no shortening of B.T. was observed unless PCV rose to at least 30%. In particular, 2 uraemic patients with B.T. >15 min and PCV values of 21% and 19% were transfused on several occasions. PCV rose to 23%, 30% and 35% in the first patient and to 25% and 34% in the second one. The corresponding B.T. were >15 min,>15 min and 0 min 30 sec and > 15 and 9 min 30 sec. In a group of 15 patients with uraemia-unrelated anemias (PCV between 20% and 34%) the median B.T. was 300 sec (range 120-450 sec) whereas in a group of 15 uraemic patients with comparable PCV values, the median B.T. was 390 sec (range 180 - 900 sec) (p<0.05, paired student's t test) . It is concluded that among other factors red cells may contribute to the defective haemostasis in uraemic patients.
EFfect Of Platelet Aggregation Inhibitor On Foetal Outcome In Cases Of Eph Gestosis
Authors: Bhattacharya N , Bhattacharya S , Mukherjee K , Bose N , Das B , Chakravorti T , Pradhan P , Samanta B
Published: July 2018

42 mothers with clinical features of mild to moderate specific gestosis (Oedema, Proteinuria, Hypertension) with mean age 29.6±2.8 yrs SD, mean diastolic pressure at 28 weeks 98±4.4, mean parity 2.1±1.1, were enrolled in a placebo controlled double blind trial to see the effect of Dipyridamole (a platelet aggregation inhibitor mainly) in 100 mg t.i.d. on the augmentation of the placental perfusion, by changing the microplatelet thrombi, from 28 weeks up to term. Mothers randomized and grouped equally. Group A received placebo and Group B received drugs in the schedule mentioned. Two cases started premature labour (Group A) and excluded from study. The mean foetal wt in Group B 2700±67 and in Group A 2462±142, expressed in Gms with SD. Fibrinoid area stained with Phosphotungstic acid Aniline Blue of Mallory, was estimated for point counting of W. Ahere (The Placenta, pp. 83-84, Ed. P. Gruenwald, MTP, 1975). The result of the counting suggested a positive physiological correlationship with the outcome of the foetal weight in this tentative study.
Quantitation of the Coagulation Inhibition in Vivo Due to Breakdown Products of Fibrin
Authors: Mitchell P. S , Beller F. K
Published: July 2018

Degradation products of human fibrinogen were prepared by in vitro lysis of fibrin clots by urokinase activation and injected into rabbits on a quantitative basis. The dose necessary to anticoagulate the animal was equal to 2½ to 3 times the animals’ fibrinogen level. The effect on whole blood clotting time and thrombin time lasted for approximately 2 hrs. The “r” time of the TEG returned to normal after 1 hr while the “Max” value remained abnormal for more than 120 min. Degradation product E was shown to clear more rapidly than D by immunochemical techniques. The overall T ½ clearance was found to be approximately 12 hrs.
Effects of Trans-4-Aminomethylcyclohexane Carboxylic Acid as an Antifibrinolytic Agent on Arterial Wall and Experimental Atherosclerotic Lesions in Rabbits
Authors: Kato N , Morimatsu M , Tanaka K , Horie A
Published: July 2018

Effects of trans-4-aminomethylcyclohexane carboxylic acid (t-AMCHA) as an antifibrinolytic agent on the experimental arteriosclerosis produced by cholesterol feeding and on the experimental thromboembolism induced by autogenous fibrin clot injection were observed in rabbits. Effect of inhibited fibrinolysis on the arterial wall itself was also observed.

Administration of 500 mg/kg body weight of t-AMCHA highly inhibited the lysis time of serum, but there was no influence on the plasma fibrinogen level.

There was no significant difference in the cholesterol level, sudanophilia of the aorta and the accumulation of foam cells in the aorta and pulmonary arteries between t-AMCHA + cholesterol group and cholesterol group.

Edema in the subendothelial layer of the aorta and elastic pulmonary artery, proliferation and swelling of the endothelial cells, and edema of the subendothelial layer of large muscular pulmonary arteries were increased in the incidence and severity in t-AMCHA treated animals. Localized intimai fibrous thickening was found in large muscular artery in t-AMCHA treated animals. Small fibrin thrombi and angitis were rarely found in muscular pulmonary artery in t-AMCHA treated animals.

Fibrinolytic activity of blood and dissolution of clots in the pulmonary arteries were depressed by t-AMCHA treatment in the animals injected autogenous fibrin clots, while the inflammatory reaction in the arterial wall was less severe as compared with that of untreated animals.

It was reasonable to presume that the inhibition of fibrinolysis would promote the development of atherosclerosis through its influence on the fibrin dissolution on and in the arterial wall, and on the vascular permeability of the arterial wall.
Effets du Sodium et du Calcium sur la Conversion du Fibrinogène en Fibrine
Authors: Marguerie G , Hudry G , Hollard G
Published: July 2018

Une méthode simple est décrite pour étudier l’effet de la force ionique sur la transformation de fibrinogène en fibrine. L’influence du Sodium et du Calcium a été étudiée. Nos résultats semblent montrer que l’augmentation de la concentration en sel affecte la polymérisation des monomères de fibrine. Un effet particulier du calcium est discuté.
Protection by Aspirin against Experimentally Induced Arterial Thrombosis in Dogs
Authors: Danese C. A , Voleti Ch D. , Weiss H. J
Published: July 2018

The possible anti-thrombotic properties of drugs which interfere with platelet aggregation were studied. Segments of the peripheral arteries of dogs were isolated, injured either by endarterectomy or chemically by instillation of 0.1 N H2 S04 (chemical injury). Two days later, the segments were examined for the presence of thrombosis. In animals which received only a placebo, 29% of the chemically-injured segments and 43% of the endarterectomized segments became totally occluded with thrombi. Treatment with aspirin (600 mg per day) reduced this incidence to 2 and 11% respectively (p < .05) while treatment with dipyridamole (DPM) (200 mg per day) had no effect. In a second study, aspirin ingestion reduced the incidence of total occlusion in chemically-injured segments from 38 to 0%. Connective-tissue induced platelet aggregation decreased in aspirin treated animals, while DPM had no effect. The findings support previous suggestions that aspirin, perhaps by inhibiting platelet aggregation, has anti-thrombotic properties.
The Coagulability of Partially Lysed Fibrinogen Effect of pH and Ionic Strength
Authors: Triantaphyllopoulos D. C , Torres Mary
Published: July 2018

Addition of thrombin to plasma obtained from dogs injected with plasmin clotted more fibrinogen when the plasma was diluted with saline than when it was diluted with distilled water. In contrast, more fibrin was formed in dilutions with distilled water when thrombin was added to intact plasma obtained prior to the injection of plasmin.

The same phenomenon was observed with purified human fibrinogen submitted to limited digestion with plasmin and was found to be pH dependent. When the pH was greater than 7.3 more fibrin was formed if the fibrinogen was diluted with saline than if it was diluted with distilled water. The opposite was observed at pH values lower than 7.2.

Similar results were obtained with the fraction of partially lysed human fibrinogen which precipitates at 25% saturation with ammonium sulfate. The same fraction, however, obtained from partially digested bovine fibrinogen did not react exactly the same way. In dilutions with distilled water there was an inverse relationship between the pH value and the amount of protein which clotted; but the reverse did not apply to the same extent in dilutions with saline.

At variance to the above observations the clottability of purified intact fibrinogen was not significantly altered by changes in pH or in ionic strength.

The clottability of partially lysed human plasma could be reversed (more fibrin in distilled water than in saline) after exhaustive dialysis against oxalated (pH 7.0) but not against citrated (pH 7.8) saline indicating that the change in clottability was due to a change in pH.
Concentration of Platelet Cofactor I (Factor VIII) from Bovine Serum*
Authors: Mammen Eberhard F
Published: July 2018

A method for obtaining concentrates of platelet cofactor I (factor VIII) from ether extracted bovine serum has been developed. Platelet cofactor I is inactivated during the coagulation process by undergoing a complex formation, which is broken by ether extraction.

In each of 13 preparations from 1,000 ml of extracted serum an average total activity of 3,055 platelet cofactor I units was isolated. The specific activity was 4,760 units per milligram tyrosine and 138 units per milligram protein (Biuret.)

In the paper electrophoresis the fractions were homogeneous. Using immunoelectrophoretic techniques three bands were found against anti-bovine serum from rabbits. The preparations activated purified prothrombin in the presence of platelets, Ac-globulin and calcium ions. They substituted in the thromboplastin generation test for adsorbed plasma and corrected the delayed thromboplastin generation of hemophilia A plasma. They also corrected the prolonged recalcification times of hemophilia A plasma. The preparations lost their activity upon storage at room temperature and in the icebox rapidly. Also freeze drying resulted in a complete loss of activity.
Hypercephalinemia and Experimental Venous Thrombosis in the Rat
Authors: Nordöy Arne F
Published: July 2018

Summary and Conclusion

Nine, 18 and 36 mg per kg body weight of a crude cephalin prepared from rat brain were suspended in saline and injected intraperitoneally in rats. The influence on coagulation, platelet adhesiveness, antifibrinolytic activity and incidence of experimental venous thrombosis was studied.

The following observations were made:

1. The recalcification time of plasma was shortened maximally one hour after the injection, with gradual return to normal values. Normal recalcification time was obtained 24 hours after the injection of the lowest dose, whereas it was still slightly shortened after the higher doses.

2. The number of adhesive platelets increased, whereas no antifibrinolytic activity was found.

3. An increased incidence of experimental venous thrombosis was observed.

Thus, there seems to be a relation between increased platelet adhesiveness, accelerated recalcification time and the tendency to venous thrombosis.