Changes in platelet volume,morphology and RNA content in subjects treated with haemodialysis

During haemodialysis treatment, blood flows from the body to the extracorporeal circuit and vice versa. In this study, pathophysiological defects in platelets indicated by alterations in RNA content and aberrations in platelet volume and morphology are detected before and during haemodialysis treatment. In subjects receiving haemodialysis treatment, qualitative interpretation of platelet characteristics with application of light microscopic evaluation reveals only 19±11?% of platelets with appropriate staining density of the granule‐containing cytoplasm. On the contrary, a reference group of apparently healthy subjects shows 70±12?% platelets with appropriate staining density of the granule‐containing cytoplasm. During haemodialysis treatment, mean values for platelet volume, platelet distribution width and platelet large cell ratio demonstrate a tendency to decrease by 10?%, 11?% and 6?%, respectively, from the mean initial value to the value at t = 150?min. Reduction of the platelet volume parameters just mentioned is hypothesized to be due to platelet degranulation as a result of platelet activation.     

Collection of platelets with a new cell separator and their storage in a citrate-plasticized container

A new apheresis device using microprocessor control for the collection of a high-purity single-donor platelet concentrate was evaluated, as was the storage of platelets for up to 5 days in a citrate-plasticized polyvinylchloride blood bag. The study was conducted in three phases: collection of platelets for in vitro studies and determination of donor safety; autologous transfusion of platelets in healthy volunteers; and transfusion of platelets in patients requiring platelet transfusion therapy. Donors had mild hypocalcemia and minimal changes in blood counts except for a platelet count reduction from 288 +/- 50 x 10(3) (288 +/- 50 x 10(9)/L) to 217 +/- 43 x 10(3) per microL (217 +/- 43 x 10(9)/L). A mean of 3.36 +/- 1.24 x 10(11) platelets was collected in the mean volume of 214 mL with red cell and white cell contamination in the range of 10(7). Morphology and aggregation were as described previously in stored platelets. Platelet survival data in eight subjects showed a mean recovery of 61 +/- 11 percent and mean survival of 5.03 +/- 1.07 days by a weighted-mean model. Patients transfused with platelets had mean increments of 23,000 immediately and of 8000 at 24 hours; corrected count increments were 6000 at 1 hour and 4000 at 24 hours. The platelets were successful in providing hemostasis to these patients. Clinically useful 5-day-stored platelets are obtained by using this apheresis technology with a functionally closed system and a citrate-plasticized blood bag.     

Storage of platelets in additive solutions: a new method for storage using sodium chloride solution

The in vitro effect of 6-day storage of platelets prepared from 6 pooled buffy coat (BC) units and stored in a platelet storage medium containing approximately 40 percent CPD-plasma and 60 percent platelet additive solution (PAS) was evaluated. PAS is composed of sodium and potassium chloride, citrate, phosphate, and mannitol. The total count of platelets per pooled unit included in the in vitro studies (n = 25) was 376 +/- 59 x 10(9) (mean +/- SD). The present study included three steps. 1. Evaluation of platelet storage in one (n = 7) and two (n = 6) 1000-mL polyolefin containers using PAS. During storage in one container, significantly lower values were found for pH, pO2, glucose, ATP, and the ratio of ATP to AMP+ADP+ATP. The values for mean platelet volume, pCO2, lactate, and extracellular adenylate kinase activity were significantly higher. These results indicate that storage in only one polyolefin container is not appropriate for maintaining satisfactory platelet quality. During storage in two polyolefin containers, a remarkably decreased lactate production (0.07 +/- 0.02 mmol/day/10(11) platelets) was noted. 2. PAS was substituted for saline during 6-day storage in two 1000-mL polyolefin containers (n = 12). The composition of the platelet preparations was the same in all other respects. Similar in vitro results were noted with PAS and saline, which indicated that PAS has no specific effect on the storage of platelets different from that of saline.(ABSTRACT TRUNCATED AT 250 WORDS)     

First results obtained in France with the latest model of the Fresenius cell separator: AS 104

In Besan?on, we carried out 40 plateletphereses with the latest model of the Fresenius cell separator AS 104 to check this new system against the new generation of cell separators, according to the following criteria: less than 2x10 6 leukocytes (before filtration) and more than 5x10 11 platelets. The results show that platelet concentrates contained 5.04+/-0.88x10 11 platelets in a total volume of 435+/-113 mL. The mean platelet recovery was 40.95+/-4.86% (from 31.7 to 51.6). The leukocyte content was 2.28+/-5.48x10 6 and the red blood cell contamination was 3.48+/-2.38x10 8. The quality of the platelets was very satisfactory. There was no problem with donor biocompatibility or procedure safety, few adverse donor reactions (0.6%) and good therapeutic efficiency of platelet concentrates.     

In vitro evaluation of COM.TEC apheresis platelet concentrates using a preparation set and pathogen inactivation over a storage period of five days

The aim of the present study was to evaluate in vitro data on platelets collected by apheresis, processed on a preparation set followed by photochemical treatment (PCT). Fifteen single-donor platelet concentrates (PCs) were collected by apheresis (COM.TEC blood cell separator, Fresenius, Bad Homburg, Germany). The platelets were transferred to the preparation set and plasma was removed after centrifugation to resuspend the platelets in approximately 37% plasma and 63% platelet additive solution InterSol. PCT was done by exposing the platelets to amotosalen HCl followed by illumination with ultraviolet light. Blood cell counts and in vitro PLT function were measured up to 5 days. An average of 3.44 +/- 0.28 x 10(11) platelets were collected in a product volume of 351 +/- 21 mL. Plasma removal resulted in a mean platelet loss of 7.8%. After PCT, a progressive decrease in platelet function was observed. LDH level rose through storage (171 +/- 81 U/L) to levels approximating LDH levels observed post-collection (180 +/- 103 U/L). There was a gradual decrease of the platelets to respond to hypotonic shock response from 90 +/- 9 % post-plasma reduction to 48 +/- 16% at day 5. All PLT units met the European requirements for leukoreduction and the pH limit of 6.8 up to day 5 post-collection. The new preparation set was capable of producing platelet units meeting the requirements for PCT. Despite differences observed in in vitro platelet function parameters, PLTs at storage day 5 fit the German and European guidelines.     

Kinetics and mobilization from the spleen of indium-111-labeled platelets during platelet apheresis

The rate and extent of platelet mobilization from the spleen were measured, and their relationship to the removal of platelets from the peripheral blood during discontinuous flow platelet apheresis was determined in four normal volunteers. Autologous platelets were labeled with Indium-111-oxine and in vivo whole body and organ In-111 radioactivity quantitated with a scintillation camera and a computer-assisted imaging system. Dynamic changes in splenic radioactivity were monitored during 12 cycles of platelet apheresis. The number of platelets harvested and changes in whole body and blood In-111 activity were determined during the procedure. The platelet life-span was estimated, and the sites of sequestration of labeled platelets was measured. Platelet apheresis removed a mean of 64 percent of platelets in the circulation; i.e., 48 percent of all platelets in the body. During the procedures, 28.0 +/- 9.4 percent In-111-labeled platelets in the body were removed, splenic radioactivity decreased by 36.5 +/- 13.2 percent, and whole body activity decreased by 34.5 +/- 9.7 percent. In-111 activity in the spleen and whole body decreased in parallel, indicating a dynamic equilibrium between these pools. The life-span of the labeled platelets was 226 +/- 25 hours, similar to that of normal subjects. The major sites of sequestration of senescent platelets were the spleen (37.9 +/- 20%) and liver (30.3 +/- 5.6%); this is similar to that found in normal subjects. We conclude that as platelets are removed from the peripheral blood, the blood pool is rapidly and effectively replenished from the splenic platelet pool. These two pools are in dynamic equilibrium and permit removal of large numbers of platelets without resultant thrombocytopenia. Platelet apheresis does not adversely effect platelet life-span, and the sequestration pattern in the reticuloendothelial system is normal.     

Recovery and life span of 111indium-radiolabeled platelets treated with pathogen inactivation with amotosalen HCl (S-59) and ultraviolet A light

BACKGROUND: A photochemical treatment (PCT) method to inactivate pathogens in platelet concentrates has been developed. The system uses a psoralen, amotosalen HCl, coupled with ultraviolet A (UVA) illumination. STUDY DESIGN AND METHODS: Three sequential clinical trials evaluated viability of PCT platelets prepared with a prototype device. Posttransfusion recovery and lifespan of (111)Indium-labeled autologous 5 day-old platelets in healthy subjects was assessed. In the first study, 23 subjects received transfusions of autologous PCT and/or control platelets. In a second study, 16 of these subjects received PCT platelets processed with a Compound Adsorption Device (CAD) (PCT-CAD) to reduce patient exposure to residual amotosalen. In the third study, the effect of gamma-irradiation on PCT platelets was studied. Data from control transfusions from Study A were used for paired comparisons in the latter 2 studies. RESULTS: Mean PCT-CAD platelet recovery for the 16 subjects with paired data was 42.5 +/- 8.7% versus 50.3 +/- 7.7% for control platelets, mean difference of 7.8% (p < 0.01). Mean lifespan for PCT-CAD platelets was 4.8 days (+/-1.3) versus 6.0 days (+/-1.2) for control platelets, mean difference of 1.3 days (p < 0.01). Platelet recovery and lifespan were similar to PCT-CAD for PCT without CAD treatment and PCT-CAD with gamma-irradiation. CONCLUSION: Viability of 5 day-old PCT platelets was less than for control platelets. However, both were within ranges reported for 5 day-old platelets.     

Plasma glycolate concentrations under conditions of dialysis

Plasma glycollate and oxalate concentrations were measured in 20 patients undergoing chronic haemodialysis treatment. The mean plasma glycollate level was 173.7 +/- 52.9 mumol/l, which was not significantly different from the normal value (means = 145.8 +/- 37.8 mumol/l). The mean plasma oxalate concentration (means = 128.7 +/- 25.6 mumol/l) was about 8 times higher than the value found in normal volunteers (means = 16.8 +/- 6.0 mumol/l). During haemodialysis lasting for 6 hours the plasma oxalate concentration decreased by 53.5%. However, no decline in plasma glycollate levels was noted. Since glycollate was not found in ultrafiltrates obtained in vivo, it is concluded that glycollate is not eliminated during haemodialysis treatment.     

Platelet collection using the IBM 2997 cell separator

Platelets were collected using the dual-channel module on the IBM 2997 Blood Fraction Separator. We carried out 320 procedures to harvest platelets for therapeutic purposes and yielded 5.1 +/- 1.5 X 10(11) platelets (mean +/- SD). Infusion into previously unsensitized recipients with hypomegakaryocytic thrombocytopenia achieved increments at 1 hr of 19 +/- 7.3 X 10(9)/liter/m2 (mean +/- SD) and at 24 hr of 15 +/- 6.3 X 10(9)/liter/m2. The only consistent donor reaction was mild hypocalcaemia, easily corrected by calcium gluconate infusion. Changes in donor packed-cell volume and white cell count were not statistically altered (p greater than 0.05) but donor platelet counts fell from 216 +/- 43.1 X 10(9)/liter to 162.5 +2- 41.7 X 10(9)/liter (mean +/- SD) (p less than 0.01). Additional plateletphereses were carried out in seven normal volunteers, using the same technique, in order that the function of the harvested platelets could be studied. Following radiochromium labelling and reinfusion into the same donors, normal in vivo recoveries were obtained at 10 min (59.4 +/- 3.4%; mean +/- SD) and platelet mean life span was also normal (218 +/- 12 hr; mean +/- SD). Furthermore, in vitro platelet factor III availability and aggregation patterns of the harvested platelets did not differ from control values and their ultrastructural appearance was normal.     

Decreased platelet serotonin transporter sites and increased platelet inositol triphosphate levels in patients with unipolar depression: effects of clomipramine and fluoxetine

BACKGROUND: The central serotonergic system has been implicated in the pathophysiology of depression and in the mechanism of the action of antidepressant drugs. The human platelet has been proposed as a peripheral model of central serotonergic neurons. METHODS: Six peripheral serotonergic parameters were determined simultaneously in 27 patients with unipolar depression before and after 2, 4, and 12 weeks of clomipramine or fluoxetine treatment according to the psychiatrist. RESULTS: In patients with depression versus matched control subjects, platelet [3H]paroxetine binding sites were found to be significantly decreased (2.10 +/- 0.70 versus 3.88 +/- 0.77 fmol/10(9) platelets; P = .0001), platelet serotonin (5-HT) content was found to be significantly decreased (1.90 +/- 1.52 versus 2.74 +/- 1.12 nmol/10(9) platelets; P = .001), and platelet inositol triphosphate levels were found to be significantly increased (2.85 +/- 0.70 versus 1.85 +/- 0.77 fmol/10(9) platelets; P = .0001). No significant difference between patients and control subjects was found for platelet [3H]-lysergic acid diethylamide ([3H]LSD) binding sites, aggregation tests with 5-HT or adenosine diphosphate and plasma 5-HT levels. Treatment with both clomipramine and fluoxetine gradually further reduced the density of platelet [3H]paroxetine binding sites and induced a dramatic decrease in platelet and plasma 5-HT levels. With clomipramine, the decreased blood 5-HT levels are associated with increased platelet [3H]LSD binding sites and aggregation responses. After 12 weeks, nonresponders to both treatments had platelet inositol triphosphate levels that were still increased (2.81 +/- 0.75 fmol/10(9) platelets) when responders levels were not different from those of control subjects (1.41 +/- 0.45 versus 1.70 +/- 0.25 fmol/10(9) platelets). CONCLUSIONS: Drug-free patients with depression had simultaneously decreased 5-HT transporter (5-HTT) sites and overstimulated phosphoinositide signaling systems. Clomipramine and fluoxetine treatments, which further decreased the density of 5-HTT sites, allowed platelet inositol triphosphate levels to return to normal values only in responders.     

Progressive platelet activation with storage: evidence for shortened survival of activated platelets after transfusion

Platelets are known to become activated during storage, but it is unclear whether such activation affects recovery or survival after platelet concentrate (PC) transfusion. With the use of flow cytometry to determine the percentage of platelets expressing the alpha-granule membrane protein 140 (GMP-140), a known adhesive ligand appearing on the platelet surface after activation, several studies were conducted. These investigations evaluated 1) the occurrence of significant platelet activation over time in PCs (n = 46) stored under standard blood bank conditions; 2) the correlation between platelet activation and platelet recovery in normal subjects after PC storage (n = 12), as assessed by the recovery of Indium-labeled platelets; and 3) the recovery of activated and unactivated platelets in thrombocytopenic cancer patients transfused with standard PCs (n = 11). It was determined 1) that an increasing duration of storage of PC was associated with increasing platelet activation as measured by the percentage of platelets expressing GMP-140, progressing from a mean of 4 +/- 2 percent (SD) on the day of collection to a mean of 25 +/- 8 percent by 5 days of storage: 2) that, in normal subjects, posttransfusion recovery of autologous platelets stored for 2 to 4 days and then labeled with In111 was inversely correlated with the percentage of activated platelets in the transfused PC (r = -0.55, p = 0.05); and 3) that, when thrombocytopenic patients were transfused with standard PCs, the recovery of the activated platelets in the transfused PCs averaged only 38 +/- 15 percent of the number predicted by the absolute platelet increment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Recovery and survival in vivo of platelet concentrates prepared with prostaglandin E1

In follow-up to previous studies showing that stimulators of adenylate cyclase inhibit the activation of platelets in platelet concentrates (PC), the posttransfusion recovery and survival of autologous platelets prepared and stored after the addition of prostaglandin E1 (PGE1) to platelet-rich plasma at a concentration of 1.3 X 10(-8) M were investigated. Six normal subjects were studied on the two occasions, using PC stored with and without PGE1 and radiolabeling with 51Cr. The mean recovery of platelets prepared with PGE1 (35.2 +/- 8.1%) was significantly lower (p less than 0.013) than that of routinely prepared platelet concentrates (46.3 +/- 9.4%). The mean life-spans of platelets prepared with and without PGE1 were 7.1 +/- 0.4 and 6.2 +/- 1.0 days, respectively (p = NS). Despite its ability to inhibit the activation of platelets during concentration and storage, prostaglandin E1 appears to reduce posttransfusion recovery of platelets significantly in this experimental model and cannot be recommended at this time as an adjunct for PC preparation.     

Reduced membrane fluidity and increased glycation of membrane proteins of platelets from diabetic subjects are not associated with increased platelet adherence to glycated collagen.

Platelets could contribute to vascular disease in diabetes through enhanced adherence to collagen exposed in injured vessels. Increased platelet adherence to collagen in diabetes could result from an alteration in platelets and/or platelet hypersensitivity to collagen that has been glycated to a greater extent. In this study, the adherence of platelets from diabetic or control subjects to glycated or nonglycated collagen coated onto glass surfaces was examined. Membrane fluidity of platelets was also determined, since decreased membrane fluidity associated with increased glycation of membrane proteins of platelets from diabetic subjects was shown in a previous study, and decreases in membrane fluidity have been shown by others to increase platelet adhesion. Thirteen diabetic subjects were compared with 13 age-and sex-matched control subjects. Collagen was glycated (9.7 nmol glucose/mg protein) by preincubation for 12 days in glucose-rich medium (500 mmol/L). A control solution of collagen incubated without glucose for the same time had 3.3 nmol glucose/mg protein. There were no differences in the adherence of platelets from diabetic and control subjects to nonglycated and glycated collagen-coated glass. The mean steady-state fluorescence polarization value (0.187 +/- 0.002) in 1.6-diphenyl-1,3,5-hexatriene-labeled platelets from diabetic subjects was significantly greater than in platelets from control subjects (0.174 +/- 0.002, p < 0.002); thus membrane fluidity in platelets from the group of diabetic subjects was decreased. The extent of glycation of membrane proteins from diabetic subjects (25.4 +/- 0.5 nmol glucose/mg protein) was significantly greater than from control subjects (20.2 +/- 0.4 nmol glucose/mg protein, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Biocompatibility of a new cell separator studied by flow cytometry: analyses of platelet antigens during apheresis and storage

BACKGROUND: Alterations of platelet antigens are known to occur during cytapheresis and storage. These changes have been shown to be dependent on the biomaterials, techniques, and devices used. In this study, the influence of a new cell separator (AMICUS) and storage container (PL-2410) on platelet glycoproteins was analyzed. STUDY DESIGN AND METHODS: During plateletpheresis and storage, the levels of platelet glycoproteins and binding of fibrinogen were determined by flow cytometry. RESULTS: During apheresis, mean channel fluorescence intensity of CD41 a did not change significantly (p = 0.06). A small increase was evident in CD42b mean channel fluorescence intensity, which rose from a baseline level of 178.6 +/- 68.3 to 231.5 +/- 97.9 at the end of the procedure (p<0.05); in CD62p-positive platelets, which increased from 2.0 +/- 0.9 percent to 9.9 +/- 3.9 percent (p<0.05); in CD63-positive platelets, which increased from 1.7 +/- 0.7 percent to 7.9 +/- 2.6 percent (p<0.05); and in the binding of fibrinogen, which increased from 1.9 +/- 0.8 percent positive platelets to 10.5 +/- 2.6 percent (p<0.05). During storage, the mean channel fluorescence intensity of CD41a and CD42b, the percentage of CD62p- and CD63-positive platelets, and the binding of fibrinogen to platelets showed no significant change. CONCLUSION: These studies show that alterations in platelet antigens and platelet activation occur to a small degree during apheresis and storage. These findings demonstrate generally good biocompatibility of this new cell separator.     

Alpha- and gamma-tocopherol in plasma, red blood cells, and platelets during plasma exchange

The effect of a rapid reduction of plasma lipoproteins on the alpha- and gamma-tocopherol levels in plasma, erythrocytes, and platelets was studied. Sixteen successive plasma exchange procedures performed weekly in an adult with heterozygous familial hypercholesterolemia were evaluated. Plasma exchange was done by intermittent flow centrifugation, exchanging one plasma volume against a 4% human albumin solution. Plasma exchange reduced in plasma alpha-tocopherol from 41.5 +/- 8.9 to 23.6 +/- 4.8 mumol/L and gamma-tocopherol from 4.9 +/- 4.1 to 2.4 +/- 2.1 mumol/L, without changing their ratios to total lipids. It diminished alpha-tocopherol in platelets from 12.97 +/- 4.37 to 10.03 +/- 1.78 mumol/10(13) cells and gamma-tocopherol from 1.43 +/- 0.55 to 1.06 +/- 0.41 mumol/10(13) cells, but did not affect erythrocyte tocopherols. The total amount removed per procedure was 47.57 +/- 13.65 mumol for alpha-tocopherol and 4.70 +/- 3.59 mumol for gamma-tocopherol. Plasma exchange increased the number of erythrocytes from 3.67 +/- 0.10.10(12) to 4.05 +/- 0.13.10(12) cells/L, without affecting their volume. Platelet count did not change, but mean platelet volume decreased from 7.7 +/- 0.5 to 6.9 +/- 0.5 fl and platelet distribution width from 15.1 +/- 0.4 to 14.9 +/- 0.5. Thus, plasma exchange reduces plasma alpha- and gamma-tocopherol to the same extent as total lipids, and decreases these tocopherols in circulating platelets, along with a reduction in platelet size and, compared to the change in erythrocyte count, a fall of platelet number.(ABSTRACT TRUNCATED AT 250 WORDS)     

单独采集血小板和浓缩血小板在保存期中的活化情况

研究单独采集血小板 (单采血小板 )和浓缩血小板在保存期中的活化情况。用流式细胞术对这两种血小板的CD62 p和CD41表达量进行测定。结果表明 :在保存 0 ,1 ,3和 5天时 ,单采血小板的CD62 p阳性率和CD41的平均荧光强度分别为 (1 8 91± 6 2 5) % ,(1 9 48± 8 2 7) % ,(2 2 82± 6 0 6) % ,(56 71± 1 1 79) %及 (8 0 9±2 38) % ,(8 1 3± 2 45) % ,(8 44± 2 51 ) % ,(1 9 87± 6 1 3) % ,而浓缩血小板的分别为 (30 65± 1 2 33) % ,(31 46± 1 1 86) % ,(32 51± 1 3 0 5) % ,(63 55± 1 3 2 7) %及 (1 0 33± 4 37) % ,(1 1 0 9± 6 61 ) % ,(1 3 46± 9 69) % ,(2 4 41± 1 0 1 5) %。二项指标均随保存时间推移而上升。对这两种血小板的计数和 pH值测定显示 ,二者均随保存时间推移而下降。在保存 0 - 3天内两种血小板的计数 ,pH值 ,CD62 p和CD41表达量无显著差异。在第 5天血小板计数和pH值出现显著下降 (P <0 0 0 1 ) ;而CD62p和CD41表达量出现显著上升 (P <0 0 0 1 )。结论 :单采血小板优于浓缩血小板     

Paired comparison of the in vivo and in vitro results of storage of platelet concentrates in two containers

Both in vitro and in vivo methods are used to test the validity of techniques for storing platelet concentrates for transfusion. In this study, the characteristics of platelet concentrates stored for 5 days at 22 degrees C in two different containers were evaluated by paired comparison using two in vitro measurements and two in vivo measurements. On two occasions, 10 normal subjects donated concentrates that were stored in containers of either the CLX system or the PL-146 system. The first plastic used was chosen at random. If necessary, a concentrate platelet count was reduced to 1,200,000 per microliters by addition of plasma to avoid pH fall. Mean recoveries were 48.2 +/- 10.6 percent (mean +/- 1 SD) and 42.4 +/- 7.8 percent for platelets stored in containers of the CLX and PL-146 systems, respectively. Similarly, survivals (T 1/2 in days) were 3.4 +/- 0.8 and 3.0 +/- 0.7, respectively. Since a paired design was used, the superiority of the CLX system was demonstrable with a one-tailed paired t test. If a paired design had not been used, a pooled t test would have been appropriate and the differences would not have been significant. This result emphasizes the value of the paired design. Furthermore, two in vitro measurements that reflect platelet morphology, dispersion of the size distribution and extent of shape change with adenosine diphosphate, were superior for platelets stored in CLX containers as well, suggesting a relationship between these measurements and in vivo viability.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduced number of angiotensin II receptors on platelets in insulin-dependent diabetes

Angiotensin II receptors on platelets were studied in 13 patients with uncomplicated type I diabetes mellitus and in 15 age-matched normal subjects. Receptor density on cells from the diabetic patients was 15% lower than the normal subjects (5.2 +/- 0.8 SD sites/platelet in diabetic patients and 6.4 +/- 0.8 in normals, P less than 0.001), but there were no differences in receptor affinity as measured by Kd (4.9 +/- 1.5 X 10(-10) mol/l in diabetic patients and 5.4 +/- 1.4 X 10(-10) mol/l in normals). Plasma concentrations of renin and angiotensin II were similar in both groups. The reduced density of angiotensin II receptors on platelets from patients with insulin-dependent diabetes may reflect a generalized abnormality of angiotensin II receptor regulation.     

Collection of platelets depleted of red and white cells with the "surge pump" adaptation of a blood cell separator

The surge pump is a device which modifies platelet collection of a blood cell separator so that red and white blood cell contamination is minimized. Plasma collected from the donor is directed back into the centrifuge bowl at 200 ml per min, where it causes platelets to be floated off the red cell-plasma interface and thus is collected as an almost pure platelet preparation. Fifty plateletapheresis procedures with the surge pump adaptation were compared to 50 procedures using the standard red cell method. Mean (+/- SD) white cell (greater than 95% lymphocytes) contamination was 5.4 +/- 3.1 X 10(8) cells per collection with the surge pump and 63.5 +/- 10 X 10(8) cells per collection with the standard red cell method (p less than 0.0001). Mean collection hematocrit was 8.1 +/- 2.6% with the standard method and less than 1% with the surge pump eliminating the need for crossmatch or centrifugation to remove red cells from ABO incompatible platelets. Surge pump collection produced a mean of 4.0 +/- 1.6 X 10(11) platelets compared to 5.0 +/- 2.0 X 10(11) platelets for the standard method (p less than 0.01). The mean time per run was 14.8 +/- 2.4 min with the surge pump compared with 18.1 +/- 3.3 min with the standard method (p less than 0.001). Therefore, the platelet yield per minute of procedure time was comparable with both methods (surge pump, 37.3 +/- 11.7 X 10(8) platelets per min; standard method, 39.2 +/- 14.3 X 10(8) platelets per min.). Surge pump operation was learned easily by technologists and caused no donor complications. The surge pump is a simple and effective way of minimizing white and red blood cell contamination in platelet collections from the blood cell separator studied without compromising platelets yields.     

The use of thrombin inhibitors and aprotinin in the preservation of platelets stored for transfusion

We have evaluated the use of several thrombin inhibitors (heparin, Fragmin, hirudin, and Thromstop) in combination with cyclic adenosine 3',5'-monophosphate-active agents (prostaglandin E-1 [PGE-1] plus theophylline) and aprotinin for preparation and extended storage of platelet concentrates. Replacement of citrate with heparin resulted in accelerated clumping of platelets during storage. Fragmin, a low molecular weight heparin fraction, induced a high degree of platelet clumping, even in the presence of a standard amount of citrate (citrate-phosphate-dextrose-adenine formula 1 [CPDA-1]) plus PGE-1 and theophylline. The best anticoagulant formulation appeared to be CPDA-1 containing PGE-1 plus theophylline plus aprotinin, plus either hirudin or Thromstop for preservation of platelet responsiveness and structural integrity by in vitro markers. In eight platelet concentrates prepared with these inhibitors and stored for 15 days, the plasma pH was 6.50 +/- 0.15, the PO2 was 94 +/- 29 mm Hg, the PCO2 was 27 +/- 4 mm Hg, and the hypotonic shock response was 76% +/- 25% of the initial value recorded at Day 1 (all values expressed as mean +/- SD). Only 11% +/- 3% of the cellular lactate dehydrogenase was released, 69% +/- 8% of the platelets appeared to be in a discoid shape, and the response to 20 mumol/L adenosine 5'-diphosphate remained at 50% +/- 17% of the initial value. These results were all significantly different (p less than 0.01) from data obtained for concentrates prepared without aprotinin. The use of a factor Xa inhibitor (diamidino-benzofuranyl ethane) in place of Thromstop or hirudin did not provide substantial improvement over controls without inhibitors.