bluuebunny/crossref_metadata_2025 huggingface dataset:
Complexing of Low Mr-Weight Human Urokinase In Rat Serum And Its Degradation Into Fragments Of Very Small Molecular Weight In Vivo But Not In Vitro
Authors: Schneider Ph , Ruegg M , Bachmann F
Published: July 2018

Highly purified lew molecular weight urokinase (LMR-UK), moving on SDS-PAGE (reduced and nan-reduced) as a single band of 32 kdalton, was labelled with 125I by the chlora- mine-T method. 106 cpn of this 125I-LMr-UK (94% TCA preci- pitable) were injected into the inferior vena cava of la- par atomized albino rats, which were maintained at 37°C. Blood samples were collected by cardiac puncture 5, 30 and 90 min respectively after the injection. Serun, obtained from these samples, was fractionated on a Sephadex G-100 column, calibrated with proteins of known Mr. Radioactivity was measured in the collected fractions.

In the 5 min sample, the radioactivity was distributed in 2 peaks, corresponding to 32 kdalton and to < 70 kdalton respectively. In the 30 min sample, the distribution was characterized by a diminution of the 32 kdalton peak and the appearance of a third peak corresponding to a Mr of < 4 kdalton. In the 90 min sample, the LMr-UK peak had disappeared almost completely. About 40% of the 125I-activity was present in a skewed high Mr peak with a broad maximum in the 85-100 kdalton region; ≥ 60% of the 125I-activity was recovered in late fractions corresponding to < 4 kdalton. In control experiments, pooled rat serum was incubated in vitro with 125I-LMr-UK for 5, 30 and 90 min respectively and samples were fractionated on the same column. The radioactivity distribution shewed only the 32 and > 70 kdalton peaks, but no < 4 kdalton peak.

These results suggest that LMr-UK is complexed to a carrier protein, both in vivo and in vitro, but that it is degraded into small fragments in vivo only. Attempts to characterize the nature of these complexes are in progress.
Effects Of Fibrinogen, Fragment D, And Fragment E On The Streptokinase Induced Activation Of Human Plasminogen
Authors: Strickland D K , Morris J P , Castellino F J
Published: July 2018

It has been observed by several investigators that fibrinogen acts as a streptokinase cofactor, and accelerates the rate of plasminogen conversion to plasmin in the presence of streptokinase. The purpose of this study was to investigate the streptokinase cofactor activity of fibrinogen and identify the portion of the fibrinogen molecule responsible for this activity. When human lys-plasminogen (Lys77-Asn790) was incubated with human fibrinogen (mole ratio 1:1), and catalytic amounts of streptokinase (mole ratio Pg:SK 250:1), a 6-fold increase in the rate of.plasmin production was observed over that observed in the absence of fibrinogen. This rate increase was not inhibited by 10 mM lysine. A 6 to 7-fold rate increase was also observed for the activation of Val442-plasminogen, a low molecular weight form of plasminogen with greatly reduced lysine binding ability. These results suggest that fibrinogen interaction with the lysine binding sites of plasminogen is not necessary for the increased rate of activation observed in the presence of fibrinogen. The ability of plasmin-digested fibrinogen to enhance the rate of streptokinase-induced activation of plasminogen was also investigated. Upon digestion of fibrinogen with urokinase-free plasmin, the cofactor activity increased by 50%. Subsequent isolation of fragments D and E revealed that fragment D was fully active, while no activity was found in fragment E. The activity of fragment D was stabilized by Ca2+. Further, it was shown that Ca2+ stabilized the structure of fragment D to heat denaturation using differential heat capacity scanning calorimetry. In the presence of Ca2+, the Tm was shifted by 4°, from 52°C to 56°C, while the AH value remained unchanged.
Dextran Sulfate Stimulated Fibrinolytic Activity In Whole Human Plasma: Dependence On The Contact Activation System And On 4 Urokinase-Related Antigen
Authors: Miles Lindsey A , Rothschild Zuleika , Griffin John H
Published: July 2018

The generation of fibrinolytic activity in whole human plasma in the presence of dextran sulfate was studied. Plasma was preincubated with N-flufenamyl-β-alanine to remove its antiplasmin and anti activator activities and then incubated with 50 μg/ml dextran sulfate (Mr - 500,000) for 30 min at 40. The initial fibrinolytic activity in 30 min, as assessed on a 125I-fibrin plate, was equivalent to approximately 9 ng/ml purified plasmin. A fraction of goat antibodies to plasminogen blocked the fibrinolytic activity of stimulated plasma, indicating that the activity was plasminogen dependent. Plasmas genetically deficient in either prekallikrein or Factor XII (Hageman Factor) showed a diminished initial rate of generation of fibrinolytic activity in response to dextran sulfate. However, after prolonged incubation (∼3 hr) of stimulated deficient plasmas with fibrin, the fibrinolytic activity approached that of stimulated normal plasma. When normal plasma was preincubated with the gamma fraction of goat antibodies made against purified urokinase, the dextran sulfate stimulated fibrinolytic activity was markedly decreased in a dose dependent manner. The data suggest that the fibrinolytic activity stimulated in whole human plasma in the presence of dextran sulfate and N-flufenamyl-β-alanine is dependent upon proteins of the contact activation system and also upon molecules immunologically related to urokinase.
A Novel Fibrinolytic Enzyme?
Authors: Pejhan Nooshabeh , Law Jacqueline A , Kemp Graham D
Published: July 2018

It has been known for seme time that plasma contains acid proteinases and that such enzymes are capable of the eventual digestion of fibrin under the conditions of the monochloroacetic acid assay for factor XIII action. It has also been suggested that the enzyme responsible is pepsin, present in the circulation as pepsinogen. There is also a reported case of an individual with a tendency for abnormal bleeding but with no apparent defect apart frccn an increased rate of fibrin clot dissolution at acid pH. Factor XEII, fibrinogen and all other clotting factors were apparently normal.

Characterisation of such acid proteinases has been hindered by their lew activity against conventional acid proteinase substrates. We have developed a more sensitive assay, based on fibrin clot dissolution. Using this we have noted differing rates of fibrin clot dissolution at acid pH in different individuals and isolated a relatively pure enzyme capable of digesting fibrin at acid pH. Its presence in a high molecular weight fraction and comparison of its mode of action on various substrates indicate same differences from pepsin(ogen). This, plus a more detailed examination of the properties of the substrate suggests that a role for this enzyme in physiological situations is not out of the question and that the designation of 'acid' proteinase may be inaccurate.
Prophylaxis Of Postoperative Thromboembolism: Low Dose Heparin Versus Heparin Plus Dihydroergotamin
Authors: Vinazzer H , Simma W , Dienstl E , Brücke P
Published: July 2018

In a randomized study on surgical patients,the antithrombotic efficacy of 5,000 I.U. heparin given subcutaneously in 8-hour intervals (LDH) was compared to 5,000 I.U. heparin plus 0.5 mg dihydroergotamin given subcutaneously in 12-hour intervals (LDH+DHE). Prophylaxis was started two hours preoperatively and was maintained until the patients were completely mobilized but for a minimum of one week. Patients of both sexes and of over 40 years of age undergoing major abdominal elective surgery were admitted to the study. Two groups of 100 patients each were formed. The groups were comparable by age,sex,weight,type of surgery,and number of risk factors. Thrombosis was diagnosed by the 125I-fibrinogen uptake test. In all cases of thrombosis,an additional perfusion scintigraphy of the lungs was carried out. There was a total of 35% of thromboembolic events in the LDH-group. Out of these,thrombosis was only detectable by the increase of radioactivity in 29% whilst in 6% also clinical signs of thrombosis were observed. One patient of this group died from pulmonary embolism. In the LDH+DHE group,thromboembolic events were found in 12%. In these patients,thrombosis was only detected by the increase of radioactivity with the exception of one case who also developed clinical signs of thrombosis. No pulmonary embolism was found in this group. Bleeding complications were observed in 8% of the LDH group. One of these patients required blood transfusions. In the LDH+DHE-group,increased bleeding was observed in 4% but transfusions were not required. These results speak in favour of the combined prophylaxis,even when intervals between injections are longer than in exclusive heparin prophylaxis.
Antithrombin III Activity During Intravenous And Subcutaneous Treatment With Heparin In Patients With Venous Thrombosis
Authors: Holmgren K , Andersson G , Egberg N , Johnsson H , Ljungberg B , Wilhelmsson S
Published: July 2018

Fifty patients with acute deep venous thrombosis in the leg were randomly allocated to either two daily subcutaneous injections (S.C.) or continuous intravenous infusion (I.V.) of heparin for at least five days. Most patients were given coumarols from the first day of heparin treatment. The amount of heparin required to maintain a prolongation of the APT-time 1 1/2 to 3 1/2 times was the same in both groups and daily heparin dosages varied between 25.000 and 50.000 units. Antithrombin III activity (AT III) was measured daily during heparin treatment and in some patients also AT III estimations were performed 1 to 12 months after heparin treatment i.e. during and after coumarol treatment.

Results: The mean concentration of AT III decreased progressively in both groups during heparin treatment from about 95% to 70%. The decrease in AT III was the same in patients treated with heparin S.C. as in patients treated with heparin I.V.
Predisposing Factors To Thromboembolism In Patients With Cancer Of The Prostate
Authors: Benoit G , Maisonneuve P , Talley F , Limousin-Lamothe M A , Sultan Y , Steg A
Published: July 2018

In a population of 64 patients with cancer of the prostate, 5 of them showed thromboembolic episodes after treatment with Diethyl Stilbestrol (DES) however no thromboembolic complication in patients treated with 17 bèta oestradiol (17βE2) was observed. Predisposing factors to thromboembolism were examined in untreated patients and in the same patients separated in two randomized groups after three months of treatment with either DES or 17βE2.

Before treatment no significant modifications of coagulation factors platelet count, platelet functions, anti Till, plasminogen and fibrinogen levels were observed when compared to a control population of the same age. It was also established that lipids, triglycerides (TG) and very low density lipoproteins (VLDL) were normal before treatment.

After treatment, thromboembolic episodes were only observed in the group receiving DES. Although no modifications of platelets and coagulation factors were observed, a significant increase in TG and VLDL was found. In contrast in the 29 patients treated with 17βE2 no thromboembolic complication of either the coagulation profile or TG and VLDL levels was found.

It is concluded therefore that the elevation of TG and VLDL was the only difference observed between patients treated with either DES or 17βE2. It is however unclear from our study how these parameters influence the coagulation process.

It is proposed that other dynamic coagulation investigations have to be performed in order to assume the role of TG and VLDL predisposing factors to thromboembolism.
Differences in cell cycle between human adult aortic and Vena Cava SMC In Cell Culture. A Impuls-Cytophotometric Study
Authors: Thilo D G S , Heinrich D , Peifer E , Rudloff P
Published: July 2018

Human aortic and vena cava SMCs show different growth pattern and proliferation rates in cell culture. We further tried to substantiate these differences by examination of the cell cycle phases with the impuls-cytophotometry(ICP). As reported in the previous abstract SMCs were established from explant cultures of human adult aortic and vena cava. After sufficient outgrowth the SMCs were subcultivated and used for cell cycle analysis at different intervals. Acridine orange(AO), ethidium bromide(Eb) and mithramycin(M) were used for nucleic acid staining followed by fluorescence microscopy. For ICP a nucleus suspension was prepared and stained with Eb/M.DNA-histogramms of SMC were recorded in a ICP 22 in combination with a 500-channel distribution analyzer. Results:Clear DNA-histogramms of SMC-suspension could not be obtained because of the large cell size and their tendency to form aggregates in suspension. Therefore, a nucleus suspension of the appropiate culture was prepared. The AO-stained SMCs show a green and red staining of the nucleus. In Eb/M-stained SMCs a uniformly staining was observed. Histogramms of proliferating art. SMC show a peak at 4N(about 50%), a second peak at 2N (about 40%) and a minor one at 8N (about 10%). In contrast we found only two peaks in the vena cava SMCs at 2 N (about 85%) and at 4N (about 15%).

Summary: Again these results show that there a marked differences between the art and venous SMCs. These results fit with the microscopic examinations and the growth curves for both types of SMCs. These differences have to be considered of the effect of drugs on functions of SMCs are examined.
Thrombin Inhibiting Capacity Of Normal Aorta
Authors: Swedenborg J , Dryjski M , Olsson P
Published: July 2018

The present investigation was designed to investigate the capacity of normal vessels to inactive activated coagulation enzymes.

Fresh and frozen porcine and canine aortae were exposed in virto to thrombin, dissolved in an albumin solution. Thrombin activity appearing on the vascular wall was assayed with a chromogenic substrate (S-2238-Kabi). Aortic endothelium retained considerable amounts of thrombin. After exposure of the aorta with plasma, a rapid inactivation of thrombin was observed. Exposure of the thrombin-absorbed endothelium to a modified Ringer’s solution resulted in a much slower inactivation. A similar slow inactivation was seen after exposure with plasma devoid of anti thrombin III. No difference was observed between fresh aortae and those stored in a frozen state. No inactivation occured during the observation time when the thrombin-albumin solution was mixed with the modified Ringer’s solution without presence of aortic endothelium and when mixed with normal plasma only slow activation was seen.

It is concluded that the aortic wall can take up thrombin and inactivate it. This occurs in the absence of plasma but it is greatly accelerated by plasma containing antithrombin III.
No Effect Of Persantin On Platelet Aggregation And Plasma βTg Levels In Healthy Volunteers
Authors: Lensing A W A , Sturk A , ten Cate J W
Published: July 2018

Previous studies from our laboratory revealed no effect of aspirin on plasma βTG levels in healthy volunteers as well as in patients with cerebrovascular accident. This double blind study was undertaken to investigate the effect of prolonged administration of Persantin. Two groups of 10 volunteers each received 4×100 mg Persantin or 2×200 mg daily in slow release form for 21 days. Platelet studies were performed prior to- and once every week during the trial. The volunteers refrained from smoking and were not on oral contraceptives or other drugs. No effect was observed on ADP (1 μ M f.c.) or collagen induced aggregation. All βTG plasma levels were within normal limits i.e. below 60/ml of plasma. No tendency of decreasing levels was observed. Side effects were significantly more observed in the volunteers on slow release Persantin (Mean Whitney Test α < 0.025). Side effects included sensations of a dry mouth and thirst, headache and di2Lzyness.
Plasma β-Thromboglobulin And Platelet Factor 4 In Patients With Chronic Renal Failure And Effect Of Hemodialysis
Authors: Endo Y , Mamiya M , Takahashi K ,   Satoh
Published: July 2018

We have reported that jS-thromboglobulin (β-TG) and platelet factor 4 (PF4) increased in chronic renal failure. The purpose of the current study is to reveal a correlation between plasma β-TG (Amersham Corp. England) and renal function, a correlation between plasma β-TG and PF. (Abbott Lab., USA) and the effect of hemodialysis on patients with chronic renal failure.

Significantly increased levels of plasma β-TG (76.8±25.5 ng/ml, p<0.01) were observed in 24 patients with chronic renal failure (BUN>20mg/dl), compared to normal subjects (13.2±5.6ng/ml). The increase in β-TG was highly correlated with BUN (r=0.651, p<0.01), creatinine (r=0.778, p<0.01) and creatinine clearance (r=-0.723, p<0.01). Although plasma PF4 (normal 5.0±2.0ng/ml) increased also, no statistical significance could be found. Statistical correlation between β-TG and PF4 was not found in these patients. This reason is thought to Be due to the difference of molecular weight (PF. 8000MW, β-TG 36000MW) and half-life (PF4 30min,β-TG 100min) The high levels of β-TG (89.4±3.4ng/ml) showed a further increase (109.4±5.8ng/dl, p<0.01) after dialysis. This is thought to be due to hemoconcentration, because of no adhesion of platelet to cellulose membrane but about 20% elevation in mean of other blood factors such as RBC, WBC, platelet, fibrinogen etc. The PF4 levels (before, 7.7±1.3ng/ml) which increased at 15min (55.2±19.6ng/ml, p<0.01) and 1 hr (23.7±8.4ng/ml, p< 0.01) are thought to be due to the influence of heparin infusion. The change in PF4. was not accompanied by the change in β-TG. During hemodialysis the decrease of other platelet functions such as adhesiveness, aggregation induced by ADP, collagen and PF3remained unchanged.
The Platelet Specific Proteins During Cardio Pulmonary Bypass
Authors: Cella G , Gallucci V , Vittadello O , Girolami A
Published: July 2018

Cardiopulmonary bypass is extremely damaging to platelets. In fact, it causes a quantitative and qualitative alteration in their function.

When platelets adhere and aggregate or are broken up on foreign surfaces they release their. granular contents. We evaluated the release of two platelet specific proteins B-thromboglobulin (BTG) and Platelet factor 4 (PF4) in 20 patients who underwent extracorporeal circulation for open heart surgery. All the patients were perfused with Pemco modular pump and a Bently disposable oxygenator. BTG and PF4 were estimated using commercial radioimmunoassay kits. A parallel release (basal value, under anesthesia and sternotomy, BTG:119.6 ng/ml, PF4:30 ng/ml) was present for both proteins in time dependent fashion until the end of extracorporeal circulation. High average levels were observed in patients in whom the bypass was stopped after about one hour (BTG 1606 ng/ml, PF4 745 ng/ml) and similarly in those in whom bypass was stopped after about two hours (BTG 1540 ng/ml, 745 ng/ml). No correlation was found either between the level of PF4 and the additional heparin administered after the initial standard dose (r = 0.29. p>0.10) and between the level of PF4 and the amount of heparin consumed during the bypass (r = 0.05, p>0.47).
The Effect Of Storage On Platelet Morpholog
Authors: Sturk A , Burt L M , Hakvoort T , ten cate J W , Crawford N
Published: July 2018

Platelet concentrates were stored for one, two or three days at 4°C (unagitated) or room temperature (unagitated and linearly agitated). The morphology of platelets in platelet concentrates, directly after twice washing at room temperature and after 60 min incubation of the washed platelets at 37°C was investigated by both scanning and transmission electron microscopy.

Platelets in the freshly prepared concentrates are slightly activated, i.e. show some pseudopod formation. At 4°C platelets rapidly loose their discoid shape. After three days their surface membrane shows extensive folding, they are slightly vacuolated and have lost most of their granules. Incubation of these cold-stored platelets at 37°C does not induce reversal to the discoid shape.

Room temperature storage results in reversal of the slight initial platelet activation. After three days unagitated platelets are slightly more vacuolated than platelets stored with agitation. Room temperature storage usually results in remarkably well preserved, discoid platelets. Occasionally however, agitated platelet concentrates contain a high proportion of odd shaped cells. As platelets stored at 4°C did not became discoid after incubation at 37°, the altered membrane structure could provide an explanation for their short survival upon transfusion. Our results also provide a morphological correlation with the slightly better recovery and survival of platelets stored agitated vs.- non-agitated platelets at room temperature.
Differences In The Volume Of Stress Platelets And Vincristine Stimulated Platelets
Authors: Martin J F , Francis P , Lee L , Shaw T , Macpherson J , Penington D G
Published: July 2018

The mechanisms by which thrombocytoses are produced are not understood. This study examines the size of platelets in thrombocytoses produced by two different stimuli.

Rats were given Vincristine (0.1 mg/kg intravenously) which produced an increase in platelet count from 1.0 to 1.5 × 109/ml on day 5 without a preceding thrombocytopenia. The volume of platelets from an aliquot of the whole platelet population was measured daily using a Coulter ZF counter coupled to a 2000 channel multichannel analyser.

Platelet volume was found to be log Gaussian with a mean modal volume of 2.44 f1. in a control group of rats (n=8). There was no significant difference between platelet volumes in the Vincristine treated group and the control group on any day.

In a second experiment platelet antiserum (PAS) or saline (control) was injected into groups of five rats. PAS produced a platelet count of 8% relative to the control group on day 1. Platelet modal volume was measured daily and in the control group did not significantly vary from 2.28±0.14 f1. In the PAS group on day 1 platelet volume was 4.17 ±0.70 f1, an increase of 83%. By day 6 the platelet count was 1.6 × 109/ml. and modal volume was 2.42 ± 0.08 f1. Platelet volume and count returned to control group levels by days 8 and 9 respectively.

Bone marrow microdensitometry showed a change in megakaryocyte ploidy number after injection of PAS.

The rise in platelet counts produced by vincristine and after thrombocytopenia (stress platelets) are probably produced by different mechanisms.
The Regression Of Platelet Malondialdehyde Production After A Single Intake Of Aspirin - The Effect Of Dosage
Authors: Takayama H , Okuma M , Uchino H
Published: July 2018

The regression of platelet malondialdehyde (MDA) formation in normal subjects was investigated after a single oral intake of various doses of aspirin (ASA). To increase the sensitivity of MDA determination by the use of thiobar- bituric acid reaction, platelets were incubated with arachi- donic acid. In the large dose group, the regression curve plotted as percent recovery had a initial lag phase (ILP) for 2 days and became linear thereafter. However, in the small dose group it was almost linear without ILP. The difference of the recovery time between these 2 groups was about 2 days. When the MDA formation was not completely inhibited, the degree of the maximal inhibition in the circulating platelets djd not affect the recovery time. Undetectable serum ASA 4 hrs after the intake suggested the effect of residual ASA on the recovery time could be negligible. These data support the concept that megakaryocytes could be affected m vivo by large doses of ASA, but slightly or not by its small doses which affect circulating platelets.
Study Of A Membrane Physico-Chemical Mechanism Of The Platelet Anti-Aggregating Effect Of TicloPidin
Authors: Stoltz J F , Solagna S , Nicolas A , Verry M
Published: July 2018

In view of earlier investigations which had revealed that Ticlopidin interferes with fatty acids, the authors decided to study the adsorption and penetration of the molecule on the platelet membrane, as well as its influence on the “membrane microviscosity” of the platelet membrane.

The study was carried out using two different techniques:
- study of the adsorption-penetration and/or desorption kinetic by means of a molecule labeled 14C
- study of membrane microviscosity by fluoresence polarization measurement (anisotropy of light emission) after incorporating a fluorescent molecule (1.6 diphenyl-1,3,5 hexatriene - DHP)

The measurements were carried out on normal platelet suspensions in a physiological salt medium (I = 0.145 M).

The results reveal:
- very rapid fixation of the molecule, whatever the quantities involved (<10mins)
- absence of saturation of the adsorption sites, even at very high concentrations (> 400γ/ml).
- a very low reversibility of the fixation bond (approx. 25 %) estimated by elution and by elution competition.
- a decrease (15 %) in membrane microviscosity for concentrations superior to 200 γ/ml (membrane microviscosity usually increases during platelet activation due to aggregating agents).

On the basis of these results the authors suggest that a physico-chemical mechanism of adsorption-penetration both in an on the platelet membrane might explain some of the biochemical and pharmacological effects observed
Clinical And Platelet Function Changes By Sulfinpyrazone (S) In Essential Mixed Cryoglobulinemia (Emc)
Authors: Boschetti C , Cortellaro M , Invernizzi F , Massaro P , Rigolone A , POlli E E
Published: July 2018

EMC represents a typical model of immune complexes (IC) disease. The interaction between platelets and IC through Fc receptors plays an important role in the pathogenesis of IC clinical features. The effects of 2 months’ treatment with an antiaggregating drug, sulfinpyrazone (S) (400 mg twice a day) were investigated in 15 patients (9 male and 6 female, mean age 55 yr) with EMC (cryocrit 2-40%). All patients presented with the purpura arthralgia syndrome. In 2 cases there was evidence of renal impairment (proteinuria < 1.5 g/day). Duration of EMC was 2-8 yr. The following platelet function tests were carried out on 12 patients before and after S treatment: platelet production time (PPT), CPA ratio and plasma β-TG. Basal data of platelet function: 4/12 patients had PPT < 6.5 days (normal value 9.88 ± 0.19), 4/12 had a CPA ratio of < 0.8, and 10/12 had ft-TG of > 60 ng/ml (n.v. 35.11 ±; 13.93). Seven patients showed a clinical improvement. These patients had a shorter basal PPT and lower CPA ratio than the others, and after treatment PPT was markedly lengthened (8.75→12.46 days) and the CPA ratio increased (0.774→0.995); in the other patients who showed no clinical improvement PPT and the CPA ratio remained almost unchanged (9.06→9-09 and 0.94 →0.89 respectively). Plasma β-TG levels were practically unvaried in both groups.

These data indicate that treatment with S may be useful in IC diseases, particularly in subjects in whom laboratory tests evidence accelerated platelet consumption in vivo.
Platelet Survival In Rabbits Treated With Uk37248 Or With Sulphinpyrazone
Authors: Davies J A , Menys V C
Published: July 2018

Survival time of Na51Cr-label led platelets was measured in rabbits and results calculated by linear regression. In 10 normal rabbits, survival was 81.9 ± 3-3 hours (mean ±SEM). This was not significantly different at 85.2 ± 4.6 hours in 8 rabbits in which survival was repeated following trauma to the aorta by single passage of an inflated balloon catheter. Indwelling nylon cannulae (4FG) were inserted through the femoral artery to lie the full-length of the aorta. Platelet survival was significantly (p<0.01) shortened from 79.7 ± 3.7 hours in 9 shamoperated animals to 62.2 ± 2.4 hours in 10 cannulated rabbits. Administration of the thromboxane synthetase inhibitor UK37248 at 10mg/kg in two oral doses daily did not prolong platelet survival (64.5 ± 3.4 hours, n = 14). Measurement of serum T×B2 concentration in samples taken at random indicated inhibition ranging from 10 to 95% during the five days of study. Incomplete inhibition of thromboxane synthetase might account for the lack of effect. However treatment of 4 cannulated rabbits with sulphinpyra- zone 20mg/kg/day also failed to prolong platelet survival (53.9 ± 3.0 hours). The results suggest that this model of platelet survival may prove resistent to the effects of anti-platelet drugs.
Thromboxane-Synthetase Inhibitors Could Be “Large Spectrum” Anti-Aggregating Agents
Authors: Bonne C , Martin B
Published: July 2018

“Large spectrum”anti-aggregating activity could be only achieved by agents which increased the c AMP content of platelets. Cyclo-oxygenase inhibitors could only block the Thromboxane (Tx)- dependent pathway of platelet aggregation. Conversely, Tx-synthetase inhibitors could deviate the endoperoxides metabolism to anti-aggregating prostaglandins in particular in the presence of vascular tissues. In this study we have investigated the effect of CBS634 (1-(3-hydroxy- 1 - octenyl)-imidazole nicotinic ester, dichlorhydra- teD, a potent inhibitor of T×A2 synthesis, both on the production of anti-aggregating prosta- glandins and on the simultaneous c AMP synthesis in platelets.

Rat aorta fragments pretreated with aspirin were incubated with rat platelet rich plasma in the presence or absence of tested compound, c AMP, T×B2, PGE2 and 6-keto-PGFF1α were determined by radioimmunoassays.

In the presence of CBS63U (50μM), T×B2 formation was reduced from 17 ± 2 to 0.2 ng/ml/min. In parallel, PGE production in controls was 1.4 ± 0.6 and 8 ± 1 ng/ml/min in the presence of the drug. On the other hand, 6-keto-PGF1α formation, very low in controls, rose to 4 ±1.2 ng/mV min in the presence of CBS63U. Radiochemical assays performed with c14C)-arachidonate confirmed that metabolic deviation. The increased level of c AMP formed in the presence of T×A2-synthetase inhibitor supports the hypothesis that such a drug could present a “large spectrum”antiaggregating activity.
Internal Ca2+ Interfering Drugs Alter Arachidonic Acid Metabolism And Inhibit In Vitro Platelet Functions
Authors: delaBaume H , Maclouf J , Levy-Toledano S , Caen J P
Published: July 2018

Internal Ca2+ fluxes are known to play a critical role in the activation of human blood platelets as well as for the liberation of arachidonic acid from the phospholipids.

When exogenous arachidonic acid is added to platelets, cyclooxygenase inhibitors, aspirin, flurbiprofen and indo- methacin inhibit its conversion into prostaglandin G2 and H2 and therefore aggregation as well as 14C- serotonin (5-HT) release but they did not affect bovine thrombin - and iono- phore A 23187 induced platelet aggregation and had only little influence on 14C -5 HT release. On the other hand, the intracellular calcium antagonist TMB 8 and chlorpromazine inhibit arachidonic acid-induced platelet aggregation and secretion although they do not affect thromboxane (TX) production. These agents also inhibit platelet aggregation, 14C -5-HT release as well as TX synthesis when ionophore or thrombin are the stimulators. Using a glass capillary column gas chromatography method developed for this purpose, we studied the quantitative amount of the liberated eicosanoids. At high concentrations, TMB 8 and chlorporomazine inhibited strongly arachidonic release as well as platelet aggregation and 14C - 5HT release but although TX production was abolished, arachidonic acid was still liberated and converted to some extent by the lipoxygenase pathway. These findings suggest that internal Ca2+ mobilization is a prerequisite for platelet activation as well as for arachidonic acid liberation. However, at intermediate doses, internal Ca2+ - interfering agents may also modulate the oxidative balance that exists between the cyclooxygenase and the lipoxygenase towards the latter pathway.
Familial Thrombocytopenia With Morphological Changes In Megakaryocytes: A Possible New Inherited Purpura
Authors: Frassoni F , Piovella F , Castagnola C , Almasio P , Ricetti M M , Ascari E
Published: July 2018

Results of an investigation concerning a familial thrombocytopenia with morphological abnormalities of bone marrow megakaryocytes and moderate bleeding tendency are presented. The laboratory and clinical data of a young woman and her mother are described. Both patients presented orolonged bleeding time which correlated with a low platelet count and which was not asso ciated with morphological or functional platelet impairment or plasmatic factors defects. Examination of bone marrow aspirates of both proposita revealed the presence of unusual features.

Smears revealed a great increase of megakaryo cyte count and most of them had the appearance of micromegakaryocytes. The nature of these celi was confirmed by immunofluorescence for factor VIII-related antigen and fibronectin. Electron microscopy performed on megakaryocytes showed the presence of a wide peripheral area of amornhous substance, while platelet ultrastructure did not show any abnormality.
Kinetics And Sites Of Destruction Of Indium-111-Oxine Labelled Platelets In Immune Thrombocytopenic Purpura
Authors: Heyns A duP , Badenhorst P N , Lötter M G , de Kock F , Herbst C , Pieters H , Minnaar P C
Published: July 2018

Kinetics and quantification of the sites of destruction of In-111-oxine labelled autologous platelets was investigated in eight patients with idiopathic thrombocytopenic purpura. The mean platelet count was 17 9 × 109/l; platelets were separated by differential centrifugation and labelled with 5,6 ±2,5 MBq In-111. Whole body and organ In-111-platelet distribution was quantitated with a scintillation camera and a computer assisted imaging system acquisition matrix. Areas of interest were selected with the computer and organ In-111-radioactivity expressed as a percentage of whole body activity. Mean platelet survival was 49,5+29,6h, and the survival curves exponential. Equilibrium percentage organ In-111-radioactivity was (normal values in parenthesis): spleen 33,7±8,8 (31,1 ± 10,2); liver 16,1 ± 9,5 (13,1 ± 1,3); thorax 22,8 ± 3,7 (28,8 ± 5,6). Percentage organ In-111-activity at the time when labelled platelets had been removed from the circulation was: spleen 44,5 ± 16,4 (40 ± 16); liver 16,0 ± 11,5 (32,4 ± 7,2); thorax 19,7±6,0 (17,7 ± 10,3). Thorax activity corresponds to radioactivity in the bony cage of the thorax. Three patterns of platelet sequestration were evident. Three patients had mainly splenic sequestration; two, mainly hepatic sequestration; and three, diffuse reticuloendothelial system sequestration with a major component of platelets destroyed in the bone marrow. Splenectomy was performed in two patients. The pattern of In-111-platelet sequestration was not predictive of response to glucocorticoid therapy or indicative of the necessity for splenectomy. Quantitative In-111-labelled autologous platelet kinetic studies provide a new tool for the investigation of platelet disorders.
Indium-111 Autologous Platelets In The Detection Of Experimental Pulmonary Emboli
Authors: Cella G , Tow D E , Godin P , Cunningham T , McCracken L , Sasahara A A
Published: July 2018

We investigated the efficacy of detecting fresh pulmonary emboli in dogs using 2 different age preparations of Indium-111 autologous platelets. Clots were induced in jugular veins of 18 mongrel dogs weighing 12-26 kg by ligating a segment of the jugular vein and the addition of thrombin. Clots thus formed were left in situ for 24 hours and then released into the pulmonary circulation. Pulmonary angiography (PA) was performed immediately before and after embolization. Scintillation imaging (SI) of the lungs was performed with a high resolution LFOV camera within 4 hours of embolization. There were 28 autopsy-iden tified clots in the lungs, of which 26 (92%:26/28) were detected by PA. Of these, SI detected 14. SI also detected 2 additional clots missed by PA.

Using PA as standard, the overall detection rate of SI was 54% (14/26). There was some difference between platelets of 4 hours (69%:9/13) and those labeled 24 hours before (38%:5/13). The difference was not significant. As expected, SI detectability was related to the product of concentration ratios between clot and blood (C/B) and weight (Wt) of the clots and not to either one alone: Data showed that Indium-111 platelets appeared to be a promising radiopharmaceutical for the detection of throm- boemboli and that the freshly prepared platelets should be preferred.
In Vivo Measurement Of Platelet Aggregation
Authors: Ambrus J L , Ambrus C M , Gastpar H , Spavento P , Gordon S , Weber F J
Published: July 2018

In stumptailed monkeys (Macaca arctoides) arteriovenous anastomoses were established. Into these an apparatus was inserted in which blood flows through a 20 micron pore diameter screen and blood pressure is recorded before and after the screen. Injection of 0.1 to 0.5 μgm of ADP or 1 to 2 vgm of serotonine resulted in rapid platelet aggregation on the screen even in heparinized animals. This increased pre-screen pressure and decreased post-screen pressure as recorded with strain gauges. From these data a platelet aggregation index is calculated. Platelet aggregation was significantly decreased by a series of agents which inhibit phosphodiesterases and stimulate release of prostacyclin. This includes several pyrimido- pyrimidine derivatives, methylxantine derivatives, and lmidazoquinazolinones. These agents increased circulation time of intravenously injected labeled polyploid ascites tumor cells. They decreased pulmonary embolism and thrombocytopenia following intravenous injection of tumor cells and decreased development of pulmonary metastases. These methods appear to be suitable to study platelet aggregation inhibitors and their mechanisms of action in vivo.
Effect Of Factor XIII On Platelet Aggregation. Study Of Platelet Function And Fibrin Stabilization Inhibitors
Authors: Maamer M , Demay O , Aurousseau M
Published: July 2018

There is little information on the participation of Factor XIII in platelet aggregation. Using BORN’s photometric method to study platelet aggregation induced by ADP in vitro on platelet rich plasma (PRP) of rabbit; clot solubility in 1 % monochloracetic acid and incorporation of dansylcadaverin into casein (LORAND L. et al.) to measure plasma FXIII concentration ; we showed that addition of activated F.XIII (F.XIIIa) to a PRP, aggregating power of platelets was significantly increased (+ 30.4 %, p<0.00l). Addition of inactive F.XIII or thrombin + Ca++ in concentrations used to activate F.XIII, had no significant effect on platelet aggregation induced by ADP.

When F.XIIIa was added to plasma in presence of F.XIII inhibitors as 3178 AQ (a new synthetic benzothiophen keton derivative) or monodansylcadaverin (DC) in concentrations of (3.27 × 10-4 M and 9.31 × 10-4 m respectively), the platelet aggregation was significantly inhibited (- 48.8 % and - 35.4 % respectively, p<0.001). This inhibitory effect was not seen when dipyridamole or Acetylsalicylic Acid (ASA) in concentrations of (6.18 × 10-4 M and 17.3 × 10-4 M respectively) ware added in PRP in presence of F.XIIIa

When platelet aggregation was performed without addition of F.XIIIa the inhibitory effect of 3178 AQ and DC was respectively (- 76.6 % and - 65.1 %, p<0.001), dipyridamole (- 37.6 %, p<0.00l) and ASA (-4.1%, no significant)

These results suggest that F.XIIIa increased the platelet aggregation induced by ADP and compounds which are both inhibitors of platelet aggregation and F.XIII would be more potent antithrombotic by acting on platelets and fibrin stabilization, than drugs which are inhibitors of platelet aggregation only.
Disturbance Of Platelet Function In The Nephrotic Syndrome
Authors: Walter E , Deppermann D , Andrassy K , Weber E
Published: July 2018

Thromboembolic phenomena often (30 %) complicate the nephrotic syndrome. It was therefor investigated, wether disturbed platelet functions play a role in this disease.

28 normals, 34 patients with nephrotic syndrome and 18 of them with impaired kidney function were tested. In 20 patients the measurements were repeated after administration of aspirin plus dipyridamo1e.

Patients with nephrotic syndrome showed in comparison to normals the following changes: 1. increased platelet count (p < 0.01), 2. enhanced platelet adhesiveness (Wright-test: p < 0.001), 3. increased spontaneous aggregation (PAT I: p < 0.001; PAT III: p < 0.01), 4. enhanced PF 4-activity (heparin neutralisation: p < 0.001), 5. elevated β TG-levels only in impaired kidney function. There was no difference in the reaction of platelets against ADP as well as collagen. The changes in platelet function correlated with the severity of the nephrotic syndrome (proteinurea, hypalbuminaemia, hyperlipo- proteinaemia). After aspirin plus dipyridamole administration spontaneous platelet aggregation and adhesiveness were normalized.

There is a disturbance of platelet function in patients with nephrotic syndrome, which can be reversed with antiaggregating agents.
Platelet Activation In Severe Burns
Authors: Hourdille P , Bernard P , Fialon P , Sanchez R , Boisseau M R , Soria C , Soria J
Published: July 2018

Acquired storage pool disease occurs in severe burns from the first week post-burn and during a period which depends on the severity of the burn and the presence of complications. As in congenital storage pool disease we observed a decrease of platelet ADP and serotonin content, abnormal aggregation, impaired 14c serotonin uptake. But we did not find a good correlation between the content of very dense bodies and the number of granules stained with mepacrine. In the majority of cases, the number of fluorescent granules per platelet remained normal although the ADP and 5-HT levels decreased markedly. These results suggest that mepacrine was able to visualize granular structures even if the granular content was very reduced. For this reason the mepacrine labelling test is of no use in detecting this acquired storage pool deficiency. Coagulation factors have been shown to be involved after burn injury. The decrease of prekallikrein and some time of antithrombine III which occur from the plasmatic coagulation activation is also correlated to the decrease of granular content.
Positive And Negative Platelet Aggregation Responses To Human Tumor Cells Among Different Normal Individuals
Authors: Ordinas Antonio , Bastida Eva , Jamieson G A
Published: July 2018

Heparinized platelet-rich plasma from 16 normal donors has been examined for platelet aggregation in response to 6 cultured human tumor cell lines. All donors showed maximal aggregation equal to 10 μM ADP with U87MG (glioblastoma) with the exception of one donor (#7) who gave 50% response: donor 7 reacted with no other tumor cell line. With Hut 20 (large cell lung carcinoma, 105 cells/ml) six donors (#3, 4, 7, 14, 15 and 16) failed to show aggregation. With HT 29 (adenocarcinoma, 106 cells/ml), the same six donors (#3, 4, 7, 14, 15 and 16) plus three additional donors (#5, 9 and 10) failed to show aggregation with Hut 28 (mesothelioma) and SKNMC (neuroblastoma), the same nine donors (#3, 4, 5, 7, 9, 10, 14, 15 and 16) failed to show platelet aggregation at 5 × 106 cells/ml. None of the donors showed aggregation with the A549 line (epithelial lung carcinoma). Gel-filtered platelets show no aggregation response with any cell line. Crossover studies with responders and non-responders showed no differences in the platelets from different donors but did show that the aggregation response is dependent upon a plasma component. Interaction of platelets and tumor cells is thought to be an important factor in the metastatic dissemination of human cancer. Similar tumors are known to show different degrees of metastatic activity in different patients. The present results suggest that responders and non-respondiers may be identified from aggregation data and that this differentiation may depend on the presence of unidentified plasma factor(s).
Reduction Of Tumor Metastasis By Cobra Venom Factor (CVF) Via Inhibition Of Platelet Aggregation (PA)
Authors: Gasic G J , Gasic T B
Published: July 2018

Tumor cells or plasma membrane vesicles shed by these cells can induce PA in vitro. To induce PA, vesicles first bind to platelets and then, subsequently, promote platelet release or plasma generation of a platelet aggregating material. The first step of this pathway is mediated by complement. If, for example, plasma is depleted of the complement component C3 by CVF neither binding nor PA occurs.

Blood-borne tumor cells can also aggregate platelets and this activity appears to facilitate their establishment as metastases. Since CVF at lower doses prevents thrombocytopenia and death of mice injected with tumor vesicles, we investigated the effect of CVF on lung colonies produced by iv inoculation of syngeneic tumor cells (T241 and B16). CVF (1-4 units) was given ip at 0, 4, 10, and 24 hr and tumor cells (5×104 and 2×104) inoculated iv 4 hr after the last injection of CVF. Two weeks later mice were killed and lung tumors counted. As shown by the Tavle lung tumors were significantly reduced in mice receiving the lowest doses of CVF but increased in the group treated with the highest dose

These results are probably due to different effects of different doses of CVF as inhibitor of PA and suppressor of immune responses, the lowest doses being more beneficial because of their greater antiplatelet and lower immune suppressing activity
Biochemical Platelet Abnormalities After Renal Transplantation
Authors: Capitanio A , Mannucci P M , Ponticelli C , Pareti F I
Published: July 2018

In recipients of renal transplants (RT), the biochemical defects accompanying increased platelet (plt)deposition in the grafts and shortened survival in the circulation are poorly characterized. 48 patients (pts) with RT (13 acute transplant rejections, ATR; 15 chronic transplant rejections, CTR; and 18 normofunctioning transplants, NFT)had lower pit serotonin (5HT) and higher plasma beta-thromboglobulin (BTG)than normal controls(NC). These abnormalities were more pronounced in ATR than CTR (5HT : 0.13±0.10, 0.18±0.08 ng/108 pits, respectively; BTG: 85±37, 62±49 ng/ml), but were also present in NFT compared with NC (5HT : 0.27±0.08, 0. 34±0. 08; BTG ; 39±33, 16±7). RT recipients also had an abnormal production of ptl pro staglandins, as expressed by low serum levels of thromboxane B2 (ATR: 324±241 pmol/108 pits; CTR : 260 ±180; NFT:262±170; NC: 441±155). T×B2 attained measurable plasma levels in 4 CTR pts (range : 0.7-9. 7 pmol/ml), whereas it was below the minimum detectable amount ( 0.5pmol/ml) in the remaining pts. Plasma fibrinopeptide A (FPA) was higher in ATR than in NC (2.6±0.9 ng/ml; 1.5± 0.8, respectively); in CTR and NFT , FpA was not different than in NC (1.9±1.1; 1.4±0. 9).

These findings suggest that in RT the in vivo occurrence of the pit release reaction has resulted in the extrusion of the content of cyt oplasmic organelles and the circulation of exhausted pits. The resulting abnormalities were usually proportional to the extent of graft injury,but were also present in NFT. Vasoactive, mitogenic and proaggregatory substances released from pits might damage the graft and aggravate the rejection process.