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At least 19 recordsLinked to original sources
PubMed1979

Thrombocytopenic episodes in patients with well-functioning renal allografts. Inverse relationship between platelet count and platelet size pointing to intermittent platelet destruction.

20 out of 50 patients with well-funcioning renal allograft displayed at least one platelet count below 110 X 10(9)/1 (mean -2 SD of controls). For estimation of platelet production during thrombocytopenic episodes, the percentage of large platelets in the peripheral blood was determined which revealed an inverse relationship (p less than 0.01) to the platelet count, indicating that these thrombocytopenias were due to increased platelet consumption. Immunosuppressive treatment as well as rejection processes could be excluded as major pathogenetic factors whereas anti-platelet autoantibodies may contribute to this phenomenon.

Autoantibodies↗
PubMed1979

The peripheral platelet count and the isoprenaline-induced splenic platelet pooling in response to beta-adrenoceptor blockade.

Previous reports have shown that a single, oral dose of 50 mg metoprolol (a selective beta-1-receptor antagonist) causes a significant increase in the peripheral platelet count by releasing platelets from the spleen. In the present study 20 healthy volunteers received 50 mg metoprolol and 40 mg propranolol orally. Both drugs induced a statistically significant increase in the platelet count lasting more than 5 h. In addition, the effect of metoprolol and propranolol on beta-adrenoceptor mediated splenic platelet trapping was studied on 7 healthy subjects who received intravenous infusions of isoprenaline before and after the ingestion of these 2 beta-blocking drugs. It was demonstrated that the isoprenaline mediated decrease in the venous platelet count was diminished by both propranolol and metoprolol but the former compound appeared to be more potent in this respect. We conclude that both selective and non-selective beta-receptor blockade causes an increase in the peripheral platelet concentration during rest as well as during beta-adrenoceptor stimulation.

Adrenergic beta-Antagonists↗
PubMed1978

Platelet counts in children with iron deficiency anemia.

Platelet count was evaluated in 30 children with iron deficiency anemia. It was found elevated when compared with 40 normal controls. No significant difference was found between the platelet counts in patients with hemoglobin levels higher or lower than 7 g/dl. Although no relation was observed between platelet count and transferrin saturation, it was correlated with serum iron values. After oral and/or parenteral iron therapy platelet count decreased insignificantly, while reticulocytes were found to be increased.

Adolescent↗
PubMed1979

Potentiating effect of adrenaline on adenosine diphosphate-induced reduction in rabbit circulating platelet count: inhibition by dihydroergotoxine.

The number of circulating platelets was monitored in anaesthetized rabbits by a continuous flow technique, using a Technicon Autocounter. Transient reductions in circulating platelet count induced by a submaximal dose of adenosine diphosphate (ADP) were potentiated by concomitant infusion of adrenaline at doses (1-25 microgram/kg) i.v.) which did not influence platelet count when infused alone. The adrenaline effect was dose-dependent. Repeated infusions of adrenaline at 15 min intervals resulted in reproducible reductions in circulating platelet count during an observation period of at least 105 min. Dihydroergotoxine (DHET), administered either i.v. (2.5-10 microgram/kg) or intraduodenally (i.d.; 25-100 microgram/kg), inhibited adrenaline-induced potentiation dose-dependently; ADP-induced effects were not influenced. Duration of action was relatively long, and significant inhibitory activity was still apparent 50 (i.v.) and 115 (i.d.) min after drug administration. DHET doses inhibiting adrenaline-induced potentiation of platelet aggregation in the rabbit are similar to doses used in the treatment of impaired human cerebral function. It is conceivable that DHET could prevent activation of human platelets by catecholamines released into the blood stream in clinical stress situations.

Adenosine Diphosphate↗
PubMed1979

Platelet counts in capillary blood.

Samples of venous and capillary blood were collected simultaneously from healthy adults to assess the accuracy of platelet counts in capillary blood as determined by an automated particle counter. The difference between the mean venous blood platelet count (248,300) and the mean capillary blood count (215,500) was highly significant (P less than .001). For 24% (7/29) of the subjects, the capillary blood platelet count underestimated the venous blood count by greater than or equal to 25%, with three subjects erroneously classified as thrombocytopenic. A heterogeneous group of thrombocytopenic patients showed a similar difference in mean platelet counts (venous blood: 72,500/microliter; capillary blood: 65,400/microliter; P = 0.01). In most clinical situations, capillary blood platelet counts were adequate for patient evaluation; however, when an accurate platelet count is necessary, venous blood should be used.

Blood Cell Count↗
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↗
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

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↗
PubMed1978

Peripheral platelet count in response to salbutamol before and after adrenergic beta-receptor blockade.

The effect of salbutamol (a comparatively selective adrenergic beta2-receptor agonist) on the peripheral platelet concentration was studied before and after the ingestion of either 50 mg metoprolol or 40 mg propranolol. The study was carried out on healthy males volunteers and autologous 51Cr-labelled platelets were employed at the experiments. Salbutamol was infused intravenously over a period of 6 min in a dose of 0.27 microgram.kg(-1). min(-1). Prior to metoprolol and propranolol administration a statistically significant lowering in platelet-bound radioactivity (PBR) was obtained in response to the salbutamol infusions. This salbutamol-induced fall in PBR was completely blocked by propranolol but was left unaffected by metoprolol. It is concluded that adrenergic beta2-receptor stimulation induces a transient lowering of the peripheral platelet count.

Adrenergic beta-Antagonists↗
PubMed1979

The effect of prophylactic proteinase inhibitor therapy on post-traumatic pulmonary insufficiency and platelet counts.

In a prospective double blind clinical study of 70 patients with bony trauma and shock, 35 patients were allocated into each group receiving either a placebo or Aprotinin. In both groups there was a high incidence of pulmonary insufficiency and thrombocytopaenia. In the placebo group there was a higher incidence of pulmonary insufficiency, but not its severity, with greater volumes of blood transufsion and the most severe form occurred only after decompensated shock. Thrombocytopaenia showed a similar pattern in all patients from both groups falling to a mean minimum on the 2nd day and rising thereafter. In the placebo group counts were lower in those with decompensated shock, and the fall was more profound, rapid and earlier in patients developing severe pulmonary insufficiency. Counts of less than 100,000 on the first day were associated with a high probability of severe pulmonary insufficiency subsequently occurring and this finding was not associated with greater volumes of blood transfusion. In those patients receiving Aprotinin, the subsequent incidence of severity of pulmonary insufficiency was less and not associated with increased volumes of blood transfusion. The platelet counts were not lower in decompensated shock and there was a more rapid rise from the minimum level.

Aprotinin↗
PubMed1979

Relationship of oral complications to peripheral blood leukocyte and platelet counts in patients receiving cancer chemotherapy.

Patients undergoing cancer chemotherapy often suffer from oral complications as a result of their disease and its treatment. The effects of the chemotherapy on the bone marrow and oral mucosa, coupled with the patient's immunosuppressed state and altered oral microbial flora, predispose these patients to oral mucositis, infection, and hemorrhage. The oral mucosa appears to mirror the effects of the chemotherapy on the bone marrow, as there appears to be a direct relationship between the changing peripheral blood counts and the status of the oral mucosa.

Adult↗
PubMed1979

Fresh autologous blood in open-heart surgery. Influence on blood requirements, bleeding and platelet counts.

The role of fresh autologous blood on haemostasis was studied in 30 patients undergoing aortic valve replacement. All the patients were extremely haemodiluted during the perfusion by using a non-haemic priming solution and withdrawal of 15% of the blood volume at the start of operation. In half of the patients, the autologous blood was retransfused immediately after the termination of perfusion. In the other half, donor blood was given in this period, while the retransfusion of autologous blood was delayed until three hours postoperatively. An increase of circulating platelets was found after the withdrawal of blood and replacement with double the amount of Ringer's acetate. Significantly less donor blood and plasma was transfused in the patients receiving early transfusion of autologous blood. An average reduction of 36% donor blood and 45% plasma was obtained. The blood losses were also less in these patients, but the differences were not significant.

Adult↗