Secretory response of the vessel wall to DDAVP and venous occlusion in von Willebrand's disease.

The aim of this study was to compare the secretory response of the vascular wall in vivo to DDAVP (i.v. 0.3 microgram/kg, 30 min) and to venous occlusion (VO, 20 min) in control healthy subjects, patients with von Willebrand's disease type I (vWd I) and patients with von Willebrand's disease type III (vWd III). In controls (n = 10) and vWd I (n = 12), DDAVP induced a 2 to 3-fold rise in plasma von Willebrand factor antigen (vWf: Ag), factor VIII coagulant activity (VIII: C) and tissue--type plasminogen activator antigen (t-PA:Ag). VO was less effective in increasing vWf: Ag and VIII:C but produced a greater rise in t-PA:Ag. Large increments (over 10-fold) were observed in plasmin-alpha 2-antiplasmin complexes following both stimuli. In vWd III (n = 10), DDAVP and VO failed to increase vWf:Ag, VIII:C and t-PA:Ag. No significant changes in plasmin-alpha 2-antiplasmin complexes were observed in this group. Moreover, the baseline t-PA:Ag values were significantly lower in vWd III (2.17 +/- 1.13 ng/ml) than in controls (4.84 +/- 1.97 ng/ml, p < 0.001). A significant increase in urokinase--type plasminogen activator antigen (u-PA:Ag) was found only in controls after VO. Neither controls nor patients with vWd showed any changes in plasma fibronectin levels following DDAVP. The low t-PA:Ag results and the abnormal fibrinolytic response to DDAVP and VO in patients with severe (type III) vWd indicate that their endothelial cell abnormality is more extensive than the defect in the synthesis or release of vWf.

[Comparison of platelet concentrates obtained using blood cell separators with continuous flow: CS-3000 and Cobe-Spectra]. / Porównanie jakosci koncentratów plytkowych otrzymanych przy uzyciu separatorów z przeplywem ciaglym: CS-3000 i Cobe-Spectra.

During a platelet apheresis procedure on CS-3000 the platelet concentrate (Pc) is centrifugated for about 1.5 h. In the Cobe system Pc is gradually collected in a container located outside the machine. Influence of both techniques on platelet viability and function was examined in vitro. MPV, hypotonic stress response (HSR), aggregation using ADP, activity and percent leakage of lactic dehydrogenase (LDH) were similar in both groups. ATP contents in platelets (Plts) obtained on CS-3000 reached 5.18 +/- 0.75 mumol/10(11) Plts and was significantly lower than in Plts collected on Cobe-Spectra: 7.26 +/- 1.00 mumol/10(11) Plts. The functions of Plts obtained on both blood cell separators, immediately after collection, appeared to be correct. ATP level reduction in Plts from CS-3000 suggests that prolonged centrifugation leads to Plts activation which can affect cells during storage.

[Evaluation of platelet quality obtained using conventional methods or from buffy-coat and stored at room temperature]. / Ocena jakosci plytek krwi uzyskanych metoda konwencjonalna oraz z kozuszka leukocytarno-plytkowego przechowywanych w temperaturze pokojowej.

A comparison has been made between platelet concentrates (Pcs) obtained from buffy coat (Bc) and from platelet rich plasma. The method of preparation proves to have an platelet properties in vitro. Both types of Pcs were investigated immediately after isolation as well as during the 5 day period of storage. It has been confirmed that due to the new technique the number of white cells in Pcs could be reduced 25 fold (to 2.79 +/- 1.68 x 10(6)/unit). It has also been showed that traditional way of obtaining Pcs provokes a greater platelet activation than the new technique. The storage conditions of Pcs obtained from Bc must however be practically defined because when CLX containers are used, afer 5 days an excessive pH increase (to 7.59), aggregation decline and HSR weakening are observed.

[Therapeutic plasmapheresis in patients with multiple myeloma]. / Plazmafereza lecznicza u chorych na szpiczaka plazmocytowego.

The effectiveness of therapeutic plasmaphereses with antineoplastic chemotherapy was evaluated in 25 cases of plasmocytic myeloma in stage III of progression of the proliferative process. The indication to plasmapheresis was hypergelification of serum with clinical symptoms of central nervous system disturbances, renal failure in various stages of progression, intensification of coronary symptoms, bleeding tendency. Good effects with reduced level of total protein and monoclonal protein in serum by 30-80% with regression of clinical symptoms caused by serum hypergelification were obtained in 11 cases. In the remaining patients clinical improvement of varying degree was noted when the level of total and monoclonal protein in the serum fell by 10-29%.

Venostasis but not DDAVP infusion provokes the plasma fibronectin increase.

Plasma fibronectin (pFN), von Willebrand factor antigen (vWf:Ag), factor VIII procoagulant activity, fibrinogen, euglobulin lysis time (ELT) and hematocrit were determined in healthy blood donors before and after venostasis as well as after intravenous infusion of 1-deamino-8-D-arginine vasopressin (DDAVP). Both venostasis and DDAVP provoked an increase in vWf:Ag and shortening in the ELT. In contrast, venostasis only but not DDAVP induced an increase in pFN levels which was statistically significant with and without correction for a concomitant hematocrit increment. The results indicate that there is a distinct difference in the patterns of venostasis and DDAVP mediated release of proteins from the vessel wall.

Cryoprecipitate of intermediate purity produced in a closed thaw-siphon system from DDAVP stimulated blood donor plasma.

The effects of intravenous administration of DDAVP to blood donors and the use of DDAVP plasma for the production of cryoprecipitate in the closed thaw-siphon system were evaluated. DDAVP treatment produced on the average a 3.2-fold rise in plasma levels of factor VIII. Von Willebrand factor antigen increased to a lesser extent. Cryoprecipitate prepared from 220-280 ml aliquots of DDAVP stimulated donor plasma contained 472 +/- 210 units of factor VIII and 276 +/- 130 units of von Willebrand factor antigen. The average yield of factor VIII was 57% of that in the prefrozen plasma. The specific activity of factor VIII in cryoprecipitate was 0.77 +/- 0.44 U/mg protein, comparable to that for intermediate purity concentrates. Thus, by the use of DDAVP and the thaw-siphon technique it is possible to produce cryoprecipitate 4-7 times as potent as conventionally manufactured preparations.

Chromosome aberrations in human lymphocytes exposed to tritiated water in vitro.

The induction of chromosome aberrations in human peripheral blood lymphocytes by tritiated water or 180 kV X-rays in vitro was studied. Lymphocytes were exposed to various concentrations of HTO for 2 h or for 53 h. Chromosome and chromatid type aberrations were scored during the first mitotic division after stimulation with phytohaemagglutinin. For the analysis of the dose-response relationship the data were fitted by the method of least-squares to different models. After acute exposure to tritium beta-rays and X-rays, the dicentrics + centric rings and terminal + interstitial deletions gave the best fit to the linear-quadratic function. However, data for these types of aberrations after 53 h exposure to HTO gave equally good fit to the linear and linear-quadratic functions. The best description of the dose-response relationship for chromatid aberrations is given by the linear model. In the system studied the RBE of tritium beta-rays as compared to 180 KV X-rays was 1.17 +/- 0.02.