Multivariate analysis for the understanding of typical diabetic hemostasis criteria. 2. Prevalent thrombocytic markers]

Various thrombocyte functions and metabolic criteria were investigated in 309 test persons, among them 198 Patients affected with diabetes mellitus, 67 of type I and 131 of type II as well as 111 healthy control persons. From the variety of these factors an optimal amount was determined by means of the statistical method of multivariance analysis separating both types of diabetes and healthy control persons. In addition to haemoglobin A1 concentration, thrombocyte parameters have been found together with the degree of capillary fragility, adrenalin-induced aggregation, platelet aggregation test and clot retraction, which allow individuals to be assigned diagnostically to various groups of test persons. Thus, thrombocyte functions found in both types of diabetes and normal persons exhibit differences which may contribute to a diagnostic classification.     

The effect of stabilizer composition on the thrombocytes and thrombocyte function in stored whole blood. II. Results of the thrombocyte spreading test]

The behaviour of thrombocyte spreading in ACD, AcD-A and AcD-AG stabilized blood was examined in 18 apparently healthy test persons for a storage period of 9 days. Due to an improved energy metabolism of thrombocytes the addition of adenin or guanosin respectively in ACD stabilized blood will cause the thrombocyte spreading to be widely preserved during storage.     

Effect of phospholipase A on erythrocyte and thrombocyte aggregation]

A study was made of the effect of plasmin and trypsin on the phospholipase activation, and also of the action of phospholipase A (cobra venom) on the release reaction and the erythrocyte and thrombocyte aggregation. Trypsin and fibrinolysin proved to activate phospholipase, this being accompanied by the accumulation of nonesterified fatty acids in the blood serum. Phospholipase A caused a release of the thromboplastic factor from erythrocytes and thrombocytes and their aggregation. The later is inhibited by albumin and EDTA. It is suggested that the action of the proteolytic enzymes on the blood formed elements was realized through the phospholipase activation.     

Cyclic nucleotides, prostaglandins and thrombocyte aggregation in rats poisoned with "murine" Yersinia pestis toxin

Y. pestis "mouse" toxin, introduced intraperitoneally into rats in a dose of LD100 [correction of LG100], produces phasic changes in the thrombin-induced aggregation of thrombocytes and the content of prostaglandins and cyclic nucleotides in them. As the result of the damaging action on the endothelium of blood vessels at the initial period of intoxication, the concentration of prostaglandin 6-keto F1 alpha in blood plasma and cAMP [correction of cAMR] in thrombocytes sharply decreases, which causes the enhancement of thrombin-induced cell aggregation. At a later period the level of prostaglandin E in the cells sharply rises. At later irreversible stages of shock, induced in the cells of Y. pestis "mouse" toxin, the content of cGMP in cells sharply increases, which leads to the development of the phase of thrombocyte hypoaggregation.     

The prostaglandin synthesis in marine fish thrombocyte

1. Prostaglandin (PG) syntheses from labelled highly unsaturated fatty acids were investigated in washed thrombocyte suspensions of four species of marine fish, flounder (Paralichthys olivaceus), black seabream (Acanthopagrus schlegeli), black rockfish (Sebastes schlegeli), and red seabream (Pagrus major). 2. Synthesized PGs were analyzed by thin-layer radiochromatogram scanner and high-performance liquid chromatography. 3. When [1-(14)C]arachidonic acid (AA) was incubated with washer thrombocyte suspension, AA was mainly converted to PGF(2alpha), PGE2, and PGD2 in all species. 4. It was suggested that [1-(14)C]eicosapentaenoic acid was mainly converted in PGs only in black rockfish thrombocytes, and the metabolites were mainly PGE3 and PGD3. 5 However, [1-(14)C]docosahexaenoic acid was not cyclized into PGs in all the species.     

Studies of thrombocyte function in CPD blood]

The CPD stabilizer according to Gibson with an addition of 1.25 mMol adeninesulfate and 2.50 mMol guanosine is used in blood storage for better preserving 2.3-bis-phosphoglycerate of erythrocytes. Here platelet-rich CPD plasma was investigated before and during a 3 days storage at 4 degrees C or room temperature with regard to preserving the global thrombocyte function. The latter consists in the ability to seal blood vessels and is tested by means of pressure registration in combined thrombocyte-aggregation-adhesion (DKTA method) as an ability to close the pores of a sieve by adding 10(-5) mM/l of ADP. At room temperature this thrombocyte function is approximately 0 following 3 days of storage in CPD plasma excess without shaking. When stored at 4 degrees C it is preserved to a slight degree. Loss of thrombocyte function will depend on pH, thus being particularly evident at room temperature.     

Electrorotation--a new method for investigating membrane events during thrombocyte activation. Influence of drugs and osmotic pressure

The measurement of the spin of cells in rotating high-frequency electric fields ('electrorotation') make possible the investigation of dielectric membrane properties of single cells. This method was applied to membrane permeability changes accompanying thrombocyte activation and compared with light-scattering data. Describing the dielectric behavior of platelets by a single-shell model and assuming a sufficiently low membrane conductivity of 1 X 10(-7) S/m we found for nonactivated platelets a membrane capacity of 5.5 mF/m2 and the conductivity of the internal medium was estimated to be 0.12 S/m. Upon activation, the electrorotation decreased continuously, with half-times in the range of few minutes. This could be explained assuming a 500-fold increase in membrane conductivity. The application of both local anesthetics and virostatics inhibited the decrease of electrorotation, as did hypertonic osmotic pressure. In all cases this was accompanied by inhibition of platelet aggregation. Hypotonic solutions induced self-aggregation and spontaneous loss of electrorotation. It was concluded that the increase in permeability of the granule membrane is a crucial step in the release reaction and that the electrorotation method is able to detect the incorporation of the granule membranes into the plasma membrane during activation. The advantage of this electrorotation method is that it enables measurements on a single-cell level, thus avoiding interactions between platelets.     

The question of thrombocyte substitution as a prophylactic measure in splenectomy for idiopathic thrombocytopenic purpura (ITP)]

The problem of intraoperative thrombocyte transfusion in splenectomy of patients with ITP is discussed. The indication for splenectomy cannot be equalized with that for intra-operative platelet substitution. Thrombocyte kinetic examinations with a concurrent determination of the thrombocyte turnover enable those patients to be recognized by their bleeding tendency who are particularly endangered by operations. The intraoperative platelet substitution should be limited to those patients with ITP whose turnover is markedly lowered as a manifestation of reduced thrombocytopoiesis. In these cases it is advisable to shift splenectomy to a later date.     

Thrombocyte counting with the Laborscale (PSL-1/PSA-1) particle-counting instrument by Medicor (Budapest/Hungary) and thrombocyte volume analysis in the diagnosis of selected thrombocytopathies

A thrombocyte counting technique is presented in comparison with the chambre counting according to the German Book of Medicaments (DAB 7 D.L.) GDR on the particle counting device "Laborscale" (PSL-1/PSA-1) of Medicor by using a thrombofuge (70 g). The composition of reagents accounts for problems of measurement which are caused by the device and influences the separation of particles. The possibility of recording the curve of thrombocyte volume distribution and calculating the average thrombocyte volume (VM) is demonstrated by means of a normal collective of test persons as well as by intravascular disorders of haemostasis and during cytostatic therapy.     

The thrombocyte-activation factor and endotoxin-induced thrombocyte activation

The effect of PAF in aggregation of platelets induced by endotoxin was studied in experiments in vitro. It is indicated that in high concentration (1.10(-7)-1.10(-6) M) PAF did not affect the degree of aggregation of platelets induced by lipopolysaccharides (LPS) S. typhimurium and N. meningitidis. Successive addition to PRP LPS and PAF or joint addition of PAF and LPS did not change the degree of aggregation of each inductor or their sum. A lower concentration of PAF (1.10(-11)-1.10(-9) M) and endotoxin caused a more expressive aggregation of platelets than their successive addition. Stimulating activity of PAF on endotoxin-induced aggregation, perhaps, is caused by involvement of metabolism of arachidonic acid during blood platelets activation.     

Platelet aggregation, rheological parameters and blood glucose profiles in diabetic children (type I) treated with human and porcine insulin

In a three-year bicentric cross-sectional investigation on type I diabetic children between six and eighteen years of age, blood sugar profiles and spontaneous thrombocyte aggregation were assessed besides anamnestic and clinical data. In the children treated with human insulin raised spontaneous thrombocyte aggregation was significantly more frequent than in those treated with porcine insulin. At the same time blood sugar fluctuation from day to day measured between seven and nine a.m. tended to be raised in the children treated with human insulin; the fluctuation in the diurnal profile measured for fourteen days was indeed very much greater. Since the two groups were comparable as to sex distribution, age, duration of disease, quality of compensation, application and dose of insulin, the greater fluctuation of blood sugar in the children treated with human insulin appears to be the cause for the raised spontaneous thrombocyte aggregation.     

Effect of ultraviolet ray irradiation of blood on thrombocyte function and cholesterol level

Action of the ultraviolet irradiation of autologous blood on thrombocyte function and serum cholesterol values. By means of a screen pressure measurement in vitro in patients with arterial occlusive disease during the course of treatment with ultraviolet irradiation of autologous blood a normalisation of thrombocyte functions is evident. This effect lasted up to a year after beginning of treatment. In the same time a significant diminuation of serum cholesterol levels appeared. The course of these parameters permits a theoretical confirmation of the observed good clinical long term effects of the ultraviolet irradiation of autologous blood and corroborates the acceptability of this therapy in cardiological and vascular dispensaires.     

Comparison of sea turtle thrombocyte aggregation to human platelet aggregation in whole blood

The endangered sea turtles are living "fossils" that afford us an opportunity to study the hemostatic process as it likely existed millions of years ago. There are essentially no data about turtle thrombocyte aggregation prior to our studies. Thrombocytes are nucleated cells that serve the same hemostatic functions as the anucleated mammalian platelet. Sea turtle thrombocytes aggregate in response to collagen and beta-thrombin. Ristocetin induces an agglutination/aggregation response indicating the presence of a von Willebrand-like receptor, GPIb, found in all mammalian platelets. Samples treated with alpha-thrombin plus gamma-thrombin followed by ristocetin results in a rapid, stronger response than ristocetin alone. These responses are inhibited by the RGDS peptide that blocks fibrinogen cross-linking of mammalian platelets via the fibrinogen receptor, GPIIb/IIIa. Three platelet-like proteins, GPIb, GPIIb/IIIa and P-selection are detected in sea turtle thrombocytes by fluorescence activated cell sorting. Turtle thrombocytes do not respond to ADP, epinephrine, serotonin, thromboxane A2 mimetic, U46619, trypsin, or alpha-thrombin and gamma-thrombin added alone. Comparison of hemostasis in sea turtles to other vertebrates could provide a framework for understanding the structure/function and evolution of these pathways and their individual components.     

Postoperative changes of the thrombocyte number and function]

In 30 patients the number of thrombocytes was determined 24-48 hours after surgical interventions and compared with the normal range. The function of thrombocytes was determined by the method of pressure registration in combined thrombocyte-aggregation-adhesion (DKTA method). In spite of the occurring thrombocytosis there is a tendency towards a decrease of response in most cases and thus of haemostatic function of blood platelets. The influence of the thrombocyte function caused by fibrinolytic split products or by a change of prostaglandine metabolism is discussed.     

Thromboembolic risk factors in kidney transplantation: hemorheologic examination in secondary polycythemia

Cardiovascular risk factors will increase the lethality of kidney patients being under dialysis treatment and after transplantation. This risk is additionally increased after transplantation by secondary polycythemia. The paper investigates the rheological properties of the blood of 20 patients affected by secondary polycythemia after kidney transplantation, 10 patients without polycythemia after kidney transplantation and 19 test persons. Plasma viscosity, erythrocyte aggregation and whole blood viscosity were determined. As a result, an increase of erythrocyte aggregation without their deformability being changed could be found in patients affected by polycythemia after kidney transplantation. The reduced thrombocyte aggregation identified in these patients can be explained by the influence of therapy.     

Effects of forskolin and cilostazol on clot retraction

We examined the effects of two inhibitors of aggregation of human platelets the, Forskolin and Cilostazol on clot retraction. Both substances suppressed clot retraction in a dose-dependent way. Both suppress platelet aggregation because of an increase in intercellular cyclic AMP, but there was no close correlations were shown between suppression rate for clot retraction and cyclic-AMP content in platelets in the clot in each substance. Furthermore, although it has been considered that actomyosin in platelets is a major contractile source for clot retraction and that failure of actin polymerization results suppression of clot retraction. As it was difficult to obtain active actin from platelets of the reagents on the polymerization. Cilostazol accelerated actin polymerization, whereas Forskolin did not. From these findings, it was considered that the effects of both substances on clot retraction could not be interpreted directly just by the increasing effect for intracellular cyclic-AMP. Clot retraction is consider to be a in vitro model of hemostasis and its contractile force is supplied from platelets (1,2,3). Experiments used prostaglandin E-1 revealed that elevation of cyclic-AMP (c-AMP) would regulate the clot retraction, and experiments used cytochalasin B demonstrated that actomyosin is responsible to the retraction (4,5). Many date demonstrate that elevation of c-AMP level suppresses platelet aggregation (6,7). c-AMP, therefore, should play a key role on platelet activation. Forskolin and Cilostazol are newly-developed reagents as a suppress for platelet functions. Pharmacological action of these substances have been interpreted to process increase effect for intracellular c-AMP of platelets(8,9). If so, both substances should show some effect on clot retraction. Under this assumption, we examined the effects.     

Failure of therapy with thrombocyte concentrates as a sequela of anti-Kob (3b) antibodies in a patient

The report deals with a failure in transfusing thrombocyte concentrates in a patient affected with bone-marrow hypoplasia caused by thrombocyte antibodies with anti-Kob (3b) specificity. This is referred to as a rare occurrence since, in general, HLA cytotoxins are identified as underlying cause and polyspecific or anti-Zwa(P1A1) antibodies only in exceptional cases.     

Inhibition of thrombocyte aggregation by antioxidants

The effects of antioxidants (3-hydroxypyridines, 5-hydroxypyrimidines, hindered phenols) on platelet aggregation were studied. All the compounds under study possessed low anti-aggregation activity against indometacin-sensitive aggregation (activation with arachidonic acid, 50 M). Half-maximal inhibition of aggregation was achieved at a concentration similar to that of the compounds used (10(-3) M in cases of indomethacin-insensitive aggregation, platelet activation by thrombine 1.5 mu/ml and Ca2+-ionophore A23187 1.5 g/ml). 4-methyl-2.6-ditretbutyl phenol (BHT) in the concentration range of 10(-5)-4 X 10(-5) M inhibited and in the concentration range of 4 X 10(-5)-10(-4) M activated indomethacin-sensitive aggregation. The latter effect was not observed in the absence of Ca2+ ions in the incubation medium. It is concluded that the effects of the antioxidants studied on platelet aggregation were due to their non-specific action on platelet membranes.     

The effect of oxalic acid on the aggregability of human platelet rich plasma

Human platelet aggregation induced by ADP was studied after incubation with urea, methylguanidine, creatinine and oxalic acid. Oxalic acid significantly (p < 0.05) inhibits human thrombocyte aggregation. Physiopathological implications are discussed.