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OBJECTIVES: To compare the incidence and survival of acute de novo leukaemias with particular reference to political/socio-economic and environmental factors in two neighbouring countries over the three 5-year periods (1982-1996). PATIENTS: The present report covers only patients diagnosed when aged > or =65 years. SETTING: A well-defined area of Sweden, the so-called Western Swedish Health Care Region and Estonia. Population-wise, the western Swedish Region and Estonia are very similar; area-wise they are also well comparable. RESULTS: The number of acute de novo leukaemias was quite dissimilar in the two countries (Estonia, n = 137, Sweden, n = 354). The age standardized incidence rates regarding the total number of acute de novo leukaemias was 5.31 per 100,000 inhabitants/year for Estonia and 7.99 for Sweden, this difference being statistically significant. However, the difference was merely attributable to incidence rates as regards acute myeloblastic leukaemias (AML); on the contrary, differences as regards acute lymphoblastic leukaemias (ALL) and non-classifiable, undifferentiated or biphenotypic acute leukaemias (uAL) were negligible. The relative survival for the total material of patients was significantly higher for Swedish when compared with Estonian patients (P < 0.001). Thus, the relative survival for the total material of patients aged > or =65 years in Estonia at 1 year was 8.5% and at 3 years 3.5% respectively. The corresponding figures for the Swedish patients were considerably higher, 22.7 and 7.7% respectively. This difference, however, applied only for patients with AML (P < 0.001), whereas the results for patients with ALL and uAL were equally dismal. CONCLUSION: The results clearly reflect how political and socio-economic factors may influence the survival of acute leukemia patients in two neighbouring countries. [ABSTRACT FROM AUTHOR]

In the present study 27 post-myocardial infarction patients were treated with Persantin capsules (Depot-Kapseln, sustained release form), containing 200 mg dipyridamole, b.i.d. over a period of 3 weeks. Baseline levels for plasma beta-thromboglobulin (BTG), platelet factor 4 (PF4), and serum thromboxane B (TXB) were obtained on day 0 and subsequently on days 1, 3, 5, 7,14 and 21. The baseline levels for plasma BTG and PF4 as well as for serum TXB significantly exceeded those for a control group consisting of healthy subjects. The plasma values for BTG and PF4 remained unchanged during the whole study period. During the first week of study the levels for serum. TXB were unchanged; however, on days 14 and 21 the means for TXB dropped significantly. There is experimental work to suggest that dipyridamole may exert an inhibitory effect on platelet thromboxane biosynthesis. The present results support this concept. [ABSTRACT FROM PUBLISHER]

Estonia regained independence in 1991 after five decades of occupation by the Soviet Union. The present population-based survey was carried out over five consecutive 5-year study periods (1982-2006) on the incidence and survival of de novo acute leukemia patients aged ≥65 years at diagnosis in Estonia and in a well-defined area in western Sweden. During the study period of retrospective work (1982-1996), the first 10 years were carried out while Estonia was still under the mentorship of the Soviet Union. Over these years, Estonian hematologists did not have access to therapeutic measures readily available to Swedish hematologists, and the results for survival for western Swedish patients with acute myeloid leukemia (AML) far exceeded those of their Estonian counterparts. However, the results for acute lymphoblastic leukemia were equally dismal in the two countries. Subsequent prospective population-based studies were carried out during the years 1997-2006. A gradual improvement as to long-term relative survival of the Estonian AML patients was observed. When studying 2002-2006, no difference as regards relative survival at 5 years was anymore present between the two countries. Over the first 20 years of our population-based studies, it was repeatedly observed that the age-standardized incidence rate particularly for de novo AML was considerably higher for the western Swedish as compared to the Estonian cohorts. During the last 5-year study period (2002-2006), no such difference between the two countries was present, indicating that some true changes in the reporting procedure in Estonia had occurred. [ABSTRACT FROM AUTHOR]

The Philadelphia chromosome-negative (Ph-) chronic myeloproliferative neoplasms include the three well-known clinical entities polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Over time, patients with ET and PV may develop myelofibrosis (MF), and all three entities carry a risk of transformation into acute myeloid leukemia (AML). In a population-based survey during 1983-1999, we studied a total of 358 patients who were diagnosed with ET and PV in the city of Gothenburg, Sweden. At the time of diagnosis, evaluable bone marrow biopsy material was available from 280 of these patients. The current work was aimed at investigating the impact of peripheral blood counts, spleen size, and bone marrow biopsy findings at diagnosis on long-term survival and the risk of development of AML or MF in this well-defined unselected population. The variables evaluated were venous blood hemoglobin concentration, packed cell volume, white blood cell count, platelet count, and splenic enlargement; as to bone marrow biopsies, interest was focused on reticulin content, focal or generalized collagen formation, bone marrow cellularity, and megakaryocyte profile number. Over the median observation time of 15 yr, the patients with ET did not demonstrate any significant difference as to survival compared to the normal Swedish population (hazard ratio, 1.23; 95% confidence interval, 0.97-1.51; p= 0.089). The patients with PV, on the other hand, had a significantly shorter survival compared to general population (hazard ratio, 1.66; 95% confidence interval, 1.38-1.99; p< 0.001). A lower hemoglobin concentration at diagnosis of ET predicted poorer survival (p =0.0281), whereas patients with PV with splenic enlargement at diagnosis had a shorter survival (p =0.037). In the patients with ET, the risk of transformation to either MF or AML was significantly associated with low hemoglobin concentration and high white cell count at diagnosis (p =0.0037 and 0.0306, respectively). An increased reticulin content and hypercellularity in the bone marrow at diagnosis were also independent risk factors (p =0.0359 and 0.0103, respectively). The risk of transformation in patients with PV was significantly associated with splenic enlargement and increase in bone marrow reticulin content (p =0.0028 and 0.0164, respectively)., (© 2010 John Wiley & Sons A/S.)

Background: In a recent retrospective study, we investigated the incidence and survival of de novo acute leukemia (AL) patients aged 16-64 years over three 5-year periods (1982-1996) in Estonia and in the Western Swedish Health Care Region. The incidence rates were similar in the two countries, but the survival data were highly different. Thus, relative survival at 5 years for de novo AL patients in Estonia was virtually negligible, whereas the corresponding figures for the Swedish patients increased from 20.3 to 38.9% during the study period., Aim: To prospectively compare the results for incidence and outcome of de novo AL between the two countries during 1997-2001., Results: Incidence rates for de novo AL were lower in Estonia than in western Sweden but not significantly so. However, the survival for de novo AL patients in Estonia had improved considerably, with the relative survival at 5 years being 16.4%; such improvement was particularly seen in acute myeloid leukemia patients. For the Swedish patients, no change in survival was recorded., Conclusion: In Estonia, a remarkable improvement in outcome for young de novo AL patients was seen after 1996. Nevertheless, relative survival for the Estonian patients had still not reached the levels found in the Swedish cohort., (Copyright © 2011 S. Karger AG, Basel.)

Background: In a recently published retrospective population-based study over three 5-year periods (1982-1996) we investigated the outcome for de novo acute leukemia (AL) patients aged >or=65 years at diagnosis in Estonia (a country that had been occupied by the Soviet Union over 5 decades) and in the so-called Western Swedish Health Care Region. The age-standardized yearly incidence rates regarding the total number of de novo AL was 5.3/100000 inhabitant for Estonia and 8.0 for Sweden, this difference being statistically significant merely as regards acute myeloid leukemia (AML). The relative survival for the total cohort of de novo AL as well as for de novo AML was significantly longer (p<0.001) for Swedish as compared to Estonian patients., Methods: In view of the miserable outcome for the Estonian patients we decided to prospectively compare the results for incidence and outcome of de novo AL between the two countries., Results: The present report covers the first 5-year period comprising 1997-2001 and deals only with patients aged >or=65 years at diagnosis. The age-adjusted annual incidence rates for de novo AML were lower in Estonia (6.4/100000) than in Sweden (9.2/100000) but not significantly so. The present results also show that the outcome for the Estonian AML patients had improved considerably over the study period; thus, at no time point, i.e., at 1, 3 and 5 years did relative survival between the two countries differ significantly., Conclusion: Yet, as compared to the Swedish cohort relative survival for the Estonian patients did still not reach an acceptable level.

The diagnosis of polycythaemia vera (PV) has been established upon sets of clinical criteria, which require the presence of absolute erythrocytosis (AE). The most recent clinical criteria for PV, published by the World Health Organization (WHO) in 2001, also required AE, and stated that the measured red cell mass (RCM) could be replaced by a surrogate marker for AE; a haemoglobin (Hb) value of >18.5 g/dl in males and >16.5 g/dl in females. The present study evaluated the potential of venous haematocrit (Hct) and Hb values as possible surrogate markers for AE in a series of 77 consecutive patients with PV and 66 patients with apparent polycythaemia (AP), in all of whom the RCM had been previously determined. In only 35% of the male PV patients would Hb values >18.5 g/dl indicate the presence of AE. Conversely, 14% of male AP patients would be misdiagnosed as having AE. A Hb > 16.5 g/dl would predict the presence of AE in 63% of the female PV patients, but 35% of female AP cases would be misdiagnosed as having AE. However, when the Hct was > or =0.60 an AE was always present, and this was true for both male and female subjects.

In the present work the incidence and survival of acute de novo leukaemias in two neighbouring countries, were studied retrospectively over three 5-year periods, 1982-1996. The aim was to compare the above variables, particularly with respect to political/socio-economic and environmental factors, in a well defined area of Sweden, the so-called Western Swedish Health Care Region, with Estonia. Population-wise the Western Swedish Region and Estonia are very similar; area-wise they are also well comparable. The present report covers only patients diagnosed between the ages of 16-64 years. The number of acute de novo leukaemias in the two regions was quite similar (Western Sweden n = 282 and Estonia n = 237). The age standardized incidence rate regarding total acute de novo leukaemias was slightly lower in Estonia than in Western Sweden (1.49/100,000 inhabitants/year for Estonia and 1.76 for Sweden, respectively), the difference being not statistically significant. However, the survival data for the two countries were highly different (P < 0.001). Thus, the relative survival for the total group of patients aged 16-64 years in Estonia at 1 year was 20.7% and at 5 years 3.6%, respectively. The corresponding figures for the Swedish patients were considerably higher, 65.2 and 29.4%, respectively. Further, the 5 year survival significantly (P < 0.05) increased for the Swedish patients over the 3 consecutive 5-year periods. No such improvement was recorded for the Estonian patients.

Approximately 45% of newly diagnosed patients with essential thrombocythaemia (ET) demonstrate subnormal plasma erythropoietin (EPO) concentrations, which constitutes a risk factor for occlusive vascular events. In 58 ET patients, a possible association between polycythaemia rubra vera-1 (PRV-1) overexpression and subnormal plasma EPO was investigated, which was always measured prior to the institution of platelet lowering agents. At the time when PRV-1 expression was measured, 28 of 58 (48%) ET patients had received platelet lowering treatment. PRV-1 expression was measured by quantitative real-time reverse transcription-polymerase chain reaction assay of mRNA extracted from purified peripheral blood buffy coat. The cycle threshold (CT) value of PRV-1 was determined and was divided with the CT value for the housekeeping GAPDH gene transcript. A quotient <0.93 was defined as PRV-1 positive. Of the ET patients 12 of 58 (21%) were PRV-1 positive and 19 of 58 (33%) demonstrated subnormal plasma EPO. In the 58 ET patients there was a significant association between low plasma EPO and PRV-1 positive results (P = 0.001). The 30 ET patients who had not received any platelet lowering treatment showed a significant (P = 0.005) relation between PRV-1 positivity and subnormal plasma EPO. No such relationship was present in the 28 ET patients who had received prior treatment with the above drugs (P = 0.147).

Most frequently, an elevated packed cell volume (PCV) value arouses the suspicion of a polycythaemic state. The aim of the present work was to assess a few readily available variables which could help the clinician to differentiate between polycythaemia vera (PV) and apparent polycythaemia (AP). During a 5-year period, 31 consecutive newly diagnosed patients with PV were identified, and during a 4-year period 38 consecutive subjects were considered to be afflicted with AP. In each subject: (i) the red cell mass (RCM) and plasma volume were measured, (ii) the spleen size was assessed using gamma-camera imaging, and (iii) the plasma erythropoietin (EPO) concentration was determined. The diagnosis of PV was based upon recently proposed criteria. By definition, all PV patients had absolute erythrocytosis, i.e. the RCM was greater than 25% above the mean normal predicted value for the individual. There was no statistical difference between the plasma volumes for PV and AP patients. However, the mean measured/predicted plasma volume for subjects with AP was significantly lower than the mean for PV. The means for spleen scan areas (posterior and left lateral projections) for AP patients were identical to the mean reference values for our laboratory. As compared to AP, in PV the spleen scan areas were significantly increased, and the lateral spleen scan area was significantly larger than the posterior area. It was also shown that, in contrast to AP, both spleen scan areas were significantly larger in male than in female PV patients. All PV patients had plasma EPO concentrations below the lower reference limit, and in 68% of the patients undetectable EPO concentrations were present. Most AP patients (84%) had EPO values within the reference range; 8% had slightly subnormal, but not undetectable, plasma EPO levels., (Copyright 2002 S. Karger AG, Basel)

It has been shown previously that measurement of the spleen size and plasma erythropoietin (EPO) concentration are valuable adjuncts in the diagnostic work-up of patients with polycythaemia vera. The aim of the present work was to evaluate their value in the assessment of apparent polycythaemia (AP). Therefore, over a 24-month period we routinely performed bone marrow biopsies, measurement of red cell mass (RCM) and plasma volume (PV), spleen size determination by gamma camera scintigraphy and determination of the plasma EPO concentration in consecutive patients referred to us because of elevated values for packed cell volume (>0.48 in females and >0.51 in males). After having excluded patients with clonal and secondary polycythaemias we were left with 38 patients (27 males and 11 females) with AP. In all of them the measured RCM was within normal range, i.e. <36 ml/kg for males and <32 ml/kg for females. The subjects were characterized by moderate increase in RCM and a concomitant moderate decrease in PV. Thus, as an average the measured RCM exceeded the predicted values by 14% in males and by 12% in females; conversely, as compared to the predicted values the average measured value for PV was reduced by 17% in males and by 8% in females. The average RCM for males was 29+/-3 ml/kg; the corresponding figure for females was 23+/-4 ml/kg. It was shown that 86% of the subjects had plasma EPO concentrations within the control range; the remaining had values slightly above or below the control range. The mean posterior spleen scan area was 57+/-16 cm2 and mean left lateral area 57+/-17 cm2; the reference value for spleen scan area (for both projections) is 57+/-12 cm2. Of the patients 35/38 (92%) had a spleen scan area within the mean+2SD for controls and 38 subjects (100%) had values within the mean+3SD. It is concluded that measurement of plasma EPO and a careful assessment of the spleen size should always be considered in the evaluation of patients with elevated values for venous packed cell volume.

The effect of oral zinc supplementation in patients with cystic fibrosis (CF) was investigated in a placebo-controlled, double-blind, crossover study with each treatment period covering 6 months. CF patients (n = 13, aged 2 years, 3 months to 19 years, 1 month) started with placebo and after 6 months, they received zinc therapy. Another 13 patients (aged 3 years, 5 months to 16 years, 10 months) started in the reverse order. Before zinc supplementation, all CF patients had low plasma levels of zinc which normalized during treatment. This effect was, however, transient. CF patients also had low concentrations of plasma selenium. A small decrease in the number of leukocytes was also noted during zinc therapy. In response to zinc treatment, no changes in the clinical status of the patients were observed either by the investigators or by the patients. Growth velocity was the same during the placebo and zinc treatment periods. No significant changes in lung function occurred in response to either placebo or zinc. It appears that the observed low plasma zinc concentration in CF patients was due to an impaired zinc absorption from the gut which was counteracted by an increased supply of oral zinc. No beneficial effect from zinc supplementation on clinical status, growth velocity, or lung function was found in this study.

There is evidence to suggest that zinc (Zn) deficiency may be involved in the pathogenesis of anorexia nervosa (AN). In an open study of 20 females, aged 14-26 years, afflicted with AN the effect of oral zinc supplementation was investigated. In each case the diagnosis of AN was based on the criteria of DSM-III-R. After a careful history, complete physical examination and laboratory screening the subjects were started on 45-90 mg of Zn2+, as zinc sulfate, (SolvezinkR, Tika, Sweden) per day. During a follow-up period of 8-56 months 17 patients increased their body weight by more than 15%. The maximum gradual weight gain of 57% was encountered in one patient after 24 months of zinc therapy. The most rapid weight gain was recorded in a patient who increased her body weight by 24% over a period of 3 months. After the institution of zinc, weight loss was not registered in any of our patients. In 13 subjects the menstruation returned 1-17 months after the initiation of zinc therapy. None of our patients developed bulimia. The design of an ongoing multicenter placebo-controlled clinical trial of zinc supplementation to patients with AN is described.

Plasma concentration of beta-thromboglobulin (BTG) and platelet factor 4 (PF4) were measured in three consecutive blood samples from 29 healthy male blood donors. The first sample was collected after 15 min of rest, the second immediately after a phlebotomy of 450 ml blood and the third after a further 15 min of rest. The mean baseline plasma BTG and PF4 values were 68 x 5 and 13.8 +/- 0.7 ng/ml, respectively. The second sample's mean plasma values of these two platelet-specific proteins were significantly higher (88 +/- ( and 24.1 +/- 4.1 ng/ml, respectively). The plasma concentrations of BTG and PF4 in the last sample, however, had returned to baseline levels. It is concluded that significant but short-lasting platelet activation and secretion take place in healthy subjects in response to an acute but comparatively mild blood loss even though the platelets do not participate in the process of hemostasis.

30 platelet transfusions were administered to 9 thrombocytopenic patients with acute leukemias. Using the Raji cell radioimmunoassay, the serum concentration for circulating immune complexes (CIC) were determined immediately before and 10--12 h after each transfusion therapy. Elevated serum concentrations for CIC were present in 14 of the pretransfusion samples. After platelet transfusion therapy, a significant (p < 0.02) decrease in the values of CIC occurred. In these 14 transfusion studies the mean percent platelet increment was considerably lower (0.10 > p > 0.05) than the mean for the 16 transfusion studies in which the pretransfusion values for CIC were normal. These results show that CIC probably play an important role in removing transfused platelets from the circulation. Conversely, platelets are able to remove CIC from the circulation.

The template bleeding time (TBT), ADP-induced platelet aggregation, and serum production of TXB2 were measured in healthy young male subjects immediately before, and on days 1, 4 and 6 after the ingestion of 1 single dose of 500 mg acetylsalicylic acid (ASA) in 3 different formulations: Aspirin (Bayer), and the 2 enteric-coated formulations Reumyl (Hässle) and Premaspin (Lääke). The ingestion of Aspirin resulted in a significant prolongation of the TBT over a period of 6 d. However, after the ingestion of the same amount of ASA in the 2 enteric coated formulations, the TBT as measured on day 6 had become normalized. After the ingestion of Aspirin, there was no reappearance of the second wave of ADP-induced platelet aggregation during the study period; however, after the ingestion of the 2 enteric-coated formulations, secondary platelet aggregation occasionally returned on day 6. In response to the intake of each of the 3 ASA formulations, the serum TXB2 production as measured 24 h later was almost completely inhibited. In each of the 3 study groups, the TXB2 formation as measured on day 6 was still significantly impaired.

Blood was obtained from 63 consecutive patients within 24 h period after the admission to a coronary care unit for the determination of plasma platelet factor 4 (PF-4) concentration. 28 of the subjects proved to have an acute myocardial infarction (MI), 24 had evidence of ischaemic heart disease (IHD) but no MI, and the remaining 11 patients had no signs of IHD. 40 healthy subjects served as controls. The mean PF-4 value in the MI group was 10.5 +/- 0.8 ng/ml. The corresponding values for patients with and without IHD were 8.7 +/- 0.6 and 8.3 +/- 0.6 ng/ml, respectively. The control mean (5.4 +/- 0.3 ng/ml) was significantly lower (P less than 0.001) than the means for all 3 groups of patients studied. The difference between the group of MI patients and patients with IHD as well as patients without IHD was only of borderline significance (0.10 greater than P greater than 0.05).

Using a recently described platelet factor 3 (PF3) immunoinjury technique designed for the detection of antiplatelet antibody, sera from 62 patients were analysed. 30 of the subjects had systemic lupus erythematosus and the remaining 32 had other clinical disorders. Platelet survival studies were also carried out in every subject. The PF3 test proved positive in 10 of our patients. However, only 1 of these 10 subjects had shortened platelet survival. It is concluded that the PF3 test does not appear to be of use in the detection of circulating antiplatelet antibody.

Twelve non-thrombocytopenic patients ( 3 males and 9 females) with systemic lupus erythematosus (SLE) were investigated with respect to platelet size, percentage of megathrombocytes, platelet survival and platelet production. The values for platelet size and percentage of megathrombocytes did not differ from those of a control group. In the SLE group the mean platelet MLS was identical to the control mean, and all patients with SLE had values for platelet MLS within the range of the control subjects. All SLE patients but one had values for platelet turnover within the control range. For unclear reason one single SLE patient had a moderately elevated platelet turnover value. The results of the present investigation do not support the theory that a state of compensated thrombocytolysis is present in SLE.

A 16-year-old female was admitted because of rapidly progressive fatigue, severe anaemia and icterus. The S-bilirubin was 190 mumol/l, COHb 7.3% and high amounts of free Hb in plasma were present. The Coombs' direct test was strongly positive with anti-IgG but negative with anti-IgM and anti-C3. Conventional therapy with very high doses of hydrocortisone i.v., cyclophosphamide, azathioprine, and transfusions of washed packed red cells proved ineffective. During 5 consecutive days she also received i.v. infusions of gamma-globulin (25 g each day). Nevertheless, her condition deteriorated and 3 plasma exchanges were carried out with impressive clinical and laboratory effects. After the 3rd plasma exchange, the patient did not require further transfusions of packed red cells. Therapy with corticosteroids could be rapidly reduced and she was discharged after 5 weeks with a normal blood picture. Since then she has remained in excellent health.

It has previously been demonstrated that patients with infantile autism demonstrate impaired in vivo platelet behaviour. Therefore, in 14 children (13 boys and 1 girl) with infantile autism (aged 2-14, mean 6 years) and 12 healthy control boys (aged 6-15, mean 11 years) we studied in vitro platelet reactivity using ADP- and collagen-induced platelet aggregation. In each child a total of 7 different final concentrations of ADP and 4 different concentrations of collagen were employed. At all concentrations of ADP and collagen used the autistic children consistently exhibited diminished platelet aggregability; the differences, however, did not reach statistical significance. Therefore a wider panel of in vitro tests is apparently required and a larger group of patients be studied to help elucidate the functional/metabolic platelet defect met in infantile autism.

The aim was to investigate whether plasma platelet factor 4 (PF-4) in suspected acute myocardial infarction (AMI) patients could serve as a prognostic tool and identify patients at risk for future death from AMI or ischaemic heart disease (IHD). Therefore, upon admission to our coronary care unit plasma PF-4 was measured on 109 consecutive patients. 53 of them proved to have AMI, and 50 IHD but no AMI; the remaining 6 had no evidence of IHD. 24 patients died in hospital or during the follow-up period which was an average of 16.7 +/- 2.4 months. The decreased were subgrouped into those dying of AMI (n = 16), and those dying of IHD but with no AMI (n = 8). No deaths from other causes were recorded. As compared with survivors there was a tendency towards higher PF-4 values among those who died of AMI. However, patients who during follow-up suffered death from IHD proved to have significantly (p less than 0.05) higher PF-4 levels than survivors.

Sera from 21 patients with systemic lupus erythematosus (SLE) were tested with a platelet factor 3 (PF3) assay. A control serum (pooled blood group AB serum) was always run in parallel with the test sera. The test and control sera were run in duplicate and for each patient the mean recalcification time was used for the calculation of the test serum: AB serum ratio. Concomitantly, the patients' serum concentrations of circulating immune complexes (CIC) were measured by using the Raji cell radioimmunoassay. 20 healthy hospital employees served as controls. In the latter subjects the mean test serum: AB serum ratio was 0.99 (range 0.92-1.09), their CIC concentrations being less than or equal to 16 micrograms/ml. 7 of the SLE patients had CIC values less than or equal to 16 micrograms/ml, and their test serum: AB serum ratios ranged 0.95-1.09. All the remaining SLE patients had elevated values for CIC. In the total material of SLE there was a highly significant (r = -0.87; P less than 0.001) negative correlation between the test serum: AB serum ratios and the values for CIC. It is widely held that the so-called PF3 immunoinjury test detects circulating antiplatelet antibodies. The present results, however, strongly suggest that the assay rather or also detects CIC which like antiplatelet antibodies may damage platelets as we and others have shown in prior publications.

Duplicate platelet survival studies, using autologous platelets labelled in vitro with radioactive sodium chromate, were performed on six young healthy asplenic men. In the first experiment plasma, and in the second a Ringer-citrate-dextrose (RCD) solution (Abrahamsen, 1968), was employed as incubation medium. The uptake of chromate by the platelets was about 2.5 times higher in the RCD compared to the plasma experiments. An identical pattern for the immediate behaviour of infused labelled platelets was observed in the duplicate studies, and the recovery of platelet-bound radioactivity remained stable at the 90% level during 2 h post-infusion. In these experiments the means for platelet mean life span (MLS) were identical, 7.2 +/- 0.5 and 7.2 +/- 0.4 days, respectively. These values slightly, but not significantly, exceeded the mean platelet MLS for a control group consisting of 10 young healthy males (6.9 +/- 0.4 days). The means for platelet production rate (P) at the duplicate studies made on the asplenic subjects were 19 +/- 2 X 10(10) and 21 +/- 2 X 10(10) platelets per day, respectively, and did not differ from the mean for P obtained in the control group (22 +/- 2 X 10(10).

The aim was to investigate whether in the acute stage of myocardial infarction (MI) platelet activation, as measured by plasma platelet factor 4 (PF-4), excluding that in ischaemic heart disease (IHD) is taking place. Over a period of 4 d the plasma levels of PF-4 were determined on 44 consecutive patients admitted to a coronary care unit with suspected MI. 21 of them had a definite acute MI (group 1), and 13 had evidence of IHD but no MI (group 2). In the remaining 10 subjects there was no evidence of either MI or IHD. On the first day the mean plasma PF-4 concentrations in group 1 and 2 patients were 11,8 +/- 1.1 and 15.0 +/- 2.3 ng/ml, respectively; the difference between means was not statistically significant. A peak mean PF-4 for group 1 patients (17.5 +/- 4.6 ng/ml) was recorded on the second day of study. The corresponding value for group 2 patients was lower, but not significantly so. In the latter subjects no peak PF-4 was recorded. During the last 2 d of study the plasma PF-4 concentrations tended to decrease, but the means for the 2 groups did not differ statistically. Thus, at no point in time was there a significant difference between the PF-4 values for MI and IHD patients present.

Fifteen recently diagnosed patients with acute leukemias admitted for induction chemotherapy were selected for study. When thrombocytopenic (venous platelet count less than 20 X 10(9)/l) these patients received prophylactic platelet transfusions. A total of 67 platelet transfusion therapies were administered and evaluated. Using the Raji cell radioimmunoassay, the serum concentrations of circulating immune complexes (CIC) were measured immediately before and 10-12 hr after each platelet transfusion. In 36 instances, elevated values of CIC were present in the recipient's pretransfusion samples. The corresponding posttransfusion values being significantly lower (P less than 0.05). Furthermore, in those 36 instances the mean percentage for the posttransfusion platelet increment was significantly lower (P less than 0.001) than in the remaining 31 instances in which normal pretransfusion values of CIC were measured. We conclude that CIC were an important factor in rapidly removing transfused platelets from the circulation, thereby, adversely affecting the benefit of platelet transfusions.

The plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) were determined in patients with various hematologic malignancies, and the results were related to simultaneously determined venous platelet counts. All studied patients were in a steady state. The plasma beta-TG concentrations were determined on 69 occasions and the values ranged from 0 to 82 ng/ml. In 33 instances, the venous platelet count was <25 x 10 (9/1) and in two thirds of these samples beta-TG was undedectable. The highest values for plasma beta-TG were found in patients with the highest venous platelet counts. A highly significant correlation (r=0.77, p <0.001) between the values for plasma beta-TG and venous platelet count was present. The plasma concentrations for PF-4 ranged from 0 to 50 ng/ml. Similarly, there was a highly significant relationship (r=0.78, p<0.001) between the values for PF-4 and venous platelet concentration. We conclude, if the plasma levels of beta-TG and PF-4 are used as markers of platelet activation in vivo, it is necessary to simultaneously consider the platelet concentration in the collected blood.