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PubMed1977

Platelet count and disease activity in juvenile rheumatoid arthritis.

Blood samples from 41 children with juvenile rheumatoid arthritis (JRA) were studied. The platelet count was tested for possible relationship and correlation with a number of clinical and laboratory parameters. High platelet count was associated with active disease, presence of secondary amyloidosis, and poor functional capacity. The platelet count was positively correlated with the erythrocyte sedimentation rate, anemia, and granulocytosis. The platelet count thus seems to provide an additional parameter of disease activity in patients with JRA.

Adolescent↗
PubMed1976

Interrelations between ABO blood group, plasminogen, alpha1-antitrypsin, alpha2-macroglobulin and the platelet count in blood donors.

The level of plasminogen alpha1-antitrypsin, alpha2-macroglobulin and the platelet count were measured in 511 blood donors. The mean level of alpha1-antitrypsin was significantly lower in men of group B compared with that of group O. No other differences between the blood groups reached statistical significance. Woman had higher mean levels of alpha1-antitrypsin and alpha2-macroglobulin and a higher platelet count than men. The levels of plasminogen and alpha1-antitrypsin were significantly higher in women using oral contraceptive compared with those who were not. The level of alpha2-marcoglobulin fell with age until the 60-64 year age-group in men and the 40-49 year age-group in women. A positive correlation existed between the alpha1-antitrypsin and the alpha2-macroglobulin level and between the platelet count and the plasminogen level.

ABO Blood-Group System↗
PubMed1977

[Electronic platelet counting with particular reference to thrombocytopenias (author's transl)].

Platelet counts in platelet-rich plasma without hematocrit dependent correction were performed by following rapid and simple steps: 1. pre-dilution of 20 microliter of whole blood by an isotonic solution 1:25; 2. stabilized low-speed centrifugation with 55 g for 5 minutes; 3. final dilution 1 : 5000; 4. enumeration by use of a TOA platelet counter PL-100 which has been technically improved in comparison to similar machines. Erroneously high results were obtained after a too short or too low centrifugation. As reason for this artifical small pulses due to disturbances of the flow patterns around the aperture (so-called vortex-effect) can be assumed having been caused by large-volumed erythrocytes and leukocytes in the suspension. The routinely used procedure was reliable for all platelet ranges, especially in thrombocytopenias between 100 X 10(9)/l and 25 X 10(9)l. In lower ranges comparisons with visual counts are essential.

Blood Cell Count↗
PubMed1978

Electronic platelet counting with capillary blood samples--experiences in a paediatric clinic.

For several reasons, electronic platelet counts have not been generally adopted in paediatric routine laboratories. A method of platelet counting in capillary blood samples using an electronic counter is described. This is based on brief centrifugation of the blood sample after the addition of a diluent containing heparin/dextran and with a density of 1.050. The thrombocytes are uniformly suspended in the supernatant after 5 min of centrifugation at 250 g, so that the counting procedure in the electric unit can follow immediately. This simplified, dependable and reproducible method is also suitable for venous blood, and as a result of several years of successful trial, it can be recommended for routine use, especially in clinics with paediatric patients.

Blood↗
PubMed1978

Rapid reduction of platelet count in essential hemorrhagic thrombocythemia by discontinuous flow plateletpheresis.

Dramatic reduction of the platelet count by discontinuous flow plateletpheresis was achieved safely and swiftly in a patient with essential hemorrhagic thrombocythemia. The patient had a history of thrombo-occlusive arterial disease and on admission had gastrointestinal bleeding. This technic is recommended as an effective means of rapidly controlling marked increase in the platelet count and its consequences in the interval before chemotherapy becomes effective.

Aged↗
PubMed1978

Relationship between platelet count and cardiotomy suction return.

A simple, inexpensive, accurate method of measuring the amount of blood returned by the cardiotomy suction system was devised and calibrated. Preoperative and postoperative platelet counts were obtained in 76 patients with congenital heart disease in whom the amount of cardiotomy suction return was measured. The mean percentage of total perfusate returned by the cardiotomy suction system was 8.9%. Both postoperative platelet count and the percentage change between preoperative and postoperative platelet counts correlated with the amount of blood returned by the cardiotomy suction system, time on bypass, and the percentage of total perfusate aspirated by the system.

Adolescent↗
PubMed1978

Prognostic value of blood platelet counts, coagulation factors and serum fibrin/fibrinogen degradation products (FDP) in acute infections.

Platelet counts, P&P, factor V and fibrin/fibrinogen degradation products (FDP) in serum were determined in 96 patients with 100 episodes of acute infections. The aim of the study was to evaluate the possible correlation between the tests, separately and in combination, and the outcome of the patients. The prognostic value was found to be dubious (0.05 greater than P greater than 0.01) as regards both a low platelet count and a decreased level of P&P and very low (P greater than 0.2) as regards factor V. On the other hand, the demonstration of a raised S-FDP as well as the presence of more than one pathological test was of distinct prognostic value (P less than 0.001). It is concluded that coagulation tests are useful as supportive aids in the prognostic evaluation of patients with acute infectious diseases.

Acute Disease↗
PubMed1977

Assay of ristocetin co-factor using fixed platelets and a platelet counting technique.

A new assay of ristocetin co-factor has been developed which is based on platelet counting using a Coulter Counter. A modified method of washing and fixing platelets has also been devised to provide a suitable platelet preparation which can be used in this assay. These fixed platelets have consistently proved to be satisfactory and have given high levels of maximum percentage aggregation. They have been stored for periods up to 6 months without significant deterioration. The method of platelet counting is simple in operation and sensitive to relatively low levels of platelet aggregation. It is precise and seems to offer distinct advantages over existing methods.

Blood Cell Count↗
PubMed1979

Platelet counting with a laser nephelometer.

A method for platelet counting is described, based on the Laser nephelometric principle. Experimental results are reported, together with the practical considerations for the standardisation and correlation of the method, and for application of the method in the routine biochemical laboratory. Venous blood, taken with EDTA-NaCL solution according to Schulz et al (1071, Z. Klin. Chem. Klin. Biochem. 9, 329-333) is used. The blood is centrifuged at 100 g for 10 min and 10 microliter of the supernatant is added to 3000 microliter of a suspending medium (dilution 1:80); 300 microliter platelet suspension are read in a nephelometer cuvet or tube against blank. The number of platelets per liter blood are determined with the aid of a standard curve. The sensitivity and reproducibility of the method, and the correlation with the "electronic coulter counting" method are satisfactory.

Humans↗
PubMed1977

Depression of the platelet count after inoculation of mice with L1210 or L5178Y cells.

The inoculation of L1210 or L5178Y leukaemia cells decreased the platelet count of the recipient mouse before extensive infiltration of marrow was expected by either tumour line. The decrease was more pronounced after intravenous inoculation of L1210 leukaemia than after intraperitoneal inoculation. Inoculation of L5178Y cells by both routes caused an initial decrease but the count recovered to 80% of normal before becoming markedly depressed prior to death of the host. Implantation of diffusion chambers containing L1210 cells also decreased the platelet count, which later returned to normal.

Animals↗
PubMed1977

Factor-VIII activity and antigen, platelet count and biochemical changes after adrenoceptor stimulation.

Adrenaline, isoprenaline and salbutamol were administered by intravenous infusion to human subjects. Isoprenaline was covered with practolol in an attempt to reduce the unpleasantness of the circulatory effects. Changes were recorded in pulse rate and blood pressure, and in blood levels of factors V, VIII, X, XI, and XII, platelet count, lactate, pyruvate, potassium and free fatty acids. Factor VIII was studied by clotting assays, by reactions with two rabbit antisera and two human antibodies, and by desulphated agarose chromatography. At the rate at which they were adiminstered, all three drugs increased the pulse rate by 20-40 beats/min. Factor VIII rose c. 2.5 X with adrenaline but only c. 1.5 X with isoprenaline and salbutamol; but other clotting factors did not alter. Chromatography provided no evidence of a change in the size of the molecule carrying factor-VIII clotting activity. The rate of clearance of the heightened plasma activity could not be shown to differ from that of "ordinary" factor VIII infused into haemophiliacs. The platelet count rose after adrenaline, fell after salbutamol and did not change significantly after isoprenaline. Among the biochemical responses, the only significant difference between the drugs was that lactate rose after adrenaline and salbutamol but did not change after isoprenaline. The rise in factor-VIII clotting activity after adrenaline is considered to represent a real increase in blood concentration, presumably by release of additional factor VIII from stores. The evidence suggests that this could be classified as a beta2 effect; and that the quantity which can be released is unrelated to the current plasma level. The rise in platelet count produced by adrenaline may be the resultant of an alpha-mediated rise due to contraction of the exchangeable splenic pool and a beta2-mediated fall, the alpha effect predominating.

Adult↗
PubMed1979

Cytoplasmic fragments causing spurious platelet counts in the leukemic phase of poorly differentiated lymphocytic lymphoma.

A patient with a leukemic phase of poorly differentiated lymphocytic lymphoma had a spuriously high automated platelet count because of cytoplasmic fragments. The number and relative percentage of cytoplasmic fragments increased during chemotherapy. The cytoplasmic fragments did not interfere with platelet aggregation using adenosine diphosphate, collagen, and epinephrine even though they were found in platelet-rich plasma. The ultrastructure of the cytoplasmic fragments is discussed. Cytoplasmic fragments as a cause of spuriously high automated platelet counts should be considered in cases of leukemic patients.

Adult↗
PubMed1978

The peripheral platelet count in response to adrenergic alpha-and beta-1-receptor stimulation.

The aim of the present work was to investigate the effect of adrenergic alpha- and beta-1-receptor stimulation on the peripheral platelet count. The experiments were carried out on 8 healthy male volunteers using radioisotopically labelled platelets. 3 subjects received i.v. infusions of adrenaline (0.09 microgram X kg-1 X min-1) before and after the ingestion of 40 mg propranolol. In response to the first infusion there was an instant increase in the venous platelet-bound radioactivity (PBR) which amounted to 12% over basal value. This effect of adrenaline seemed to be potentiated by propranolol pretreatment. 5 subjects received i.v. infusions of the highly selective beta-1-receptor agonist H 133/22 (prenalterol, Hässle, Sweden). In response to a cumulative dose of 4.75 mg prenalterol a slight but significant (P less than 0.05) decrease in PBR occurred. It is concluded that alpha-receptor stimulation causes a depletion of platelets from the exchangeable splenic platelet pool resulting in a concomitant increase in the peripheral platelet count. Beta-receptor stimulation has an opposite effect on the spleen. The trapping of platelets by the spleen is mediated both via beta-1- and beta-2-receptors, but the effect of beta-2-receptor stimulation seems to predominate.

Adrenergic beta-Agonists↗
PubMed1977

The relation between baseline and 150 min platelet counts in response to selective beta-1-receptor blockade. An experimental study on healthy subjects.

In 30 healthy volunteers after an oral administration of 50 mg metoprolol basal and 150 min platelet counts were determined. A significant negative correlation (p less than 0.01) between the baseline platelet count and the percentage increase at 150 min was shown to be present. It is postulated that this observation reflects interindividual differences between the magnitude of the exchangeable splenic platelet pool.

Administration, Oral↗
PubMed1978

A modified sedimentation method for counting platelets in blood.

A sedimentation method for counting human blood platelets is proposed which uses a fluid of sp.gr. i.057 at an osmolarity of 320 milliosmols. The fluid is a mixture of Lymphoprep and Isoton II. After centrifugation at about 200 platelets are counted on an electronic particle counter.

Blood Cell Count↗
PubMed1977

The peripheral platelet count in response to intravenous infusion of salbutamol.

Five healthy male volunteers received i.v. infusions of salbutamol, a relatively selective beta-2-receptor-stimulating agent, in doses of 0.03, 0.06, 0.09 and 0.27 microgram X kg-1 X min-1 over a period of 6 min. At the three low doses the heart rate remained essentially unchanged and no significant decrease in the platelet count occurred. However, in response to 0.27 microgram X kg-1 X min-1 of salbutamol the heart rate increased by 25% over basal value (p less than 0.01) and a significant lowering (p less than 0.005) of the platelet count was obtained. The present findings suggest that the drop in the peripheral platelet concentration in response to adrenergic beta-receptor stimulation is mediated via beta-1-receptors.

Adult↗
PubMed1977

Metoprolol and the peripheral platelet count.

An acute oral administration of 50 mg metoprolol (a selective beta-1-receptor antagonist) to 18 healthy volunteers induced a significant increase in the peripheral platelet concentration lasting more than 4 h. It is suggested that this increment in the platelet count originates from the exchangeable splenic platelet pool. The mechanism by which metoprolol exerts its effect remains to be established.

Administration, Oral↗