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Results for “Platelet Count”

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At least 523 records · Page 29Linked to original sources

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↗

PubMed1995

Investigations of platelet aggregation and platelet counts from stored canine whole blood.

The effects of the long term storage of canine blood at 4 to 6 degrees C in PVC-bags containing CPDA-1 as a stabiliser on platelet aggregation and platelet counts were investigated. Aggregation induced by collagen, adenosine diphosphate or a calcium ionophore was preserved well during the first six hours, but there was then a decrease of 24 to 46 per cent in the ability of the platelets to aggregate, after which during the next three to four weeks of storage there was no further decrease in their aggregation properties. The formation of aggregates of platelets reduced the numbers of platelets counted as single thrombocytes by more than 30 per cent during the first four days. The numbers of platelets recorded varied widely with the counting method used (counting chamber or automatically) and with the ethylenediamine tetra-acetic acid content of the dilution fluid.

Adenine↗

PubMed1984

The effects of amrinone on platelet count, survival and function in patients with congestive cardiac failure.

In a prospective trial, the immediate and long-term haematological effects of amrinone were studied in sixteen patients with refractory cardiac failure. The platelet count was significantly and variably reduced in all patients and the reduction was related to log plasma amrinone concentration. Platelet survival was significantly reduced in those cases studied. No evidence of disseminated intravascular coagulation or intravascular platelet deposition was observed and the reduced platelet survival was not considered to be the result of an immunological process. Evidence of a marrow response to the reduced platelet count and survival was seen. Although no haemorrhagic symptoms were observed in the patients, the haematological side-effects were considered to be of such severity as to limit the use of this drug in clinical practice.

Adult↗

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↗

PubMed2002

TT virus of certain genotypes may reduce the platelet count in patients who achieve a sustained virologic response to interferon treatment for chronic hepatitis C.

The platelet count increases after a sustained response to interferon (IFN) treatment for chronic hepatitis C (CH-C). However, the extent of the increase differs by patient. We investigated whether concurrent TT virus (TTV) infection interferes with the improvement of thrombocytopenia. Serial serum samples were obtained from 85 noncirrhotic CH-C patients who achieved a sustained virologic response for hepatitis C virus (HCV) upon IFN treatment, and tested for TTV DNA by three polymerase chain reaction (PCR) methods (UTR, N22 and TTV genotype-1). UTR PCR can detect essentially all TTV genotypes, whereas N22 PCR primarily detects four major TTV genotypes (1-4). Eighty-four patients (84/85, 99%) were positive for TTV DNA by UTR PCR, 27 (32%) by N22 PCR and 18 (21%) by TTV genotype-1 PCR just before IFN treatment was started (baseline). A sustained virologic response for TTV was observed in 6% (5/84) by UTR PCR, 52% (14/27) by N22 PCR and 56% (10/18) by TTV genotype-1 PCR. The platelet count was significantly lower in the N22 PCR-positive group than in the N22 PCR-negative group not only at baseline (14.9+/-3.8 vs. 18.1+/-6.4x10(4)/&mgr;l, P<0.05), but also at the non-HCV-viremic state one year after the completion of IFN treatment (15.5+/-2.8 vs. 18.6+/-5.5x10(4)/&mgr;l, P<0.05), the differences also being statistically significant by TTV genotype-1 PCR, but not by UTR PCR. These results suggest that certain TTV genotypes including genotype 1 may play a role in aggravating the thrombocytopenia of CH-C patients, either alone or in concert with HCV.

Journal Article↗

PubMed2003

Impact of allogenic blood transfusions on temperature, platelet count and differential leukocyte count of patients after coronary artery bypass grafting.

We compared the median values of temperature, platelet count, white blood cell count and differential leukocyte count (neutrophils, eosinophils, basophils, lymphocytes and monocytes) just before and after coronary artery bypass grafting of patients transfused with packed red cell units (n = 119), and not transfused with packed red cell units (n = 98). Just before surgery and at 7 h, 13 h, 22 h, 46 h and 142 h after surgery, blood samples were taken. In the patient group undergoing transfusion lower median values at a significance level of alpha = 0.025 were found of their temperature postoperatively at 7 h, platelets at 22 h, 46 h and 142 h, white blood cell count at 13 h and 22 h, neutrophils at 7 h, 13 h and 22 h, lymphocytes at 46 h and 142 h, compared to the patients not transfused.

Blood Transfusion↗

PubMed1997

A prospective randomized study of three types of platelet concentrates in patients with haematological malignancy: corrected platelet count increments and frequency of nonhaemolytic febrile transfusion reactions.

We prospectively randomized 51 patients with haematological malignancy requiring platelet concentrates (PCs) to receive either single donor platelet-pheresis products (SD-PC), PCs made from pooled buffy coats (BC-PC) or pooled units of platelets made by the platelet-rich plasma method (PRP-PC). The leucocyte content of each type of PC was 0.33 (0.03-13.5), 5.68 (0.19-99.0) and 365 (65-910) x 10(6); median (range), respectively; P < 0.0001. All red cell transfusions were leucodepleted by filtration. Statistical comparison of the probability of the occurrence of a nonhaemolytic febrile transfusion reaction (NHFTR) following transfusion of PCs in patients in each group showed a significant decrease for the SD-PC and BC-PC groups (0.031 and 0.038, respectively) when compared with PRP-PC (0.171); P = 0.0001. The actual corrected platelet count increments (CCI) at 1-6 and 18-24 h post-transfusion for all three types of PC did not differ significantly. We conclude that transfusion of PRP-PC is associated with a significant increase in NHFTR.

Adult↗

PubMed2006

Acute onset of severe hemolysis, elevated liver enzymes, and low platelet count syndrome in a patient with a partial hydatidiform mole at 17 weeks gestation.

Preeclampsia is uncommon prior to 24 weeks gestation and has been associated with partial and complete hydatidiform moles. We present an unusual case in which a patient was diagnosed with preeclampsia at 17 weeks gestation. Ultrasound findings were consistent with a partial hydatidiform mole. Within 24 hours of the onset of symptoms, the patient developed severe hemolysis, elevated liver enzymes, and low platelet count syndrome, with a platelet count of 20 x 10 (9) cells/L. Termination of pregnancy was performed with rapid resolution of signs, symptoms, and laboratory abnormalities. Triploid 69,XXY was confirmed at karyotype analysis. This case demonstrates the acuteness in which life-threatening maternal conditions can arise with this uncommon complication of pregnancy, and the importance of correct identification of the characteristic ultrasonographic findings associated with a partial hydatidiform mole.

Abortion, Induced↗

PubMed1997

Effects of polyethylene glycol-conjugated recombinant human megakaryocyte growth and development factor on platelet counts after chemotherapy for lung cancer.

BACKGROUND: Polyethylene glycol (PEG)-conjugated recombinant human megakaryocyte growth and development factor (MGDF, also known as PEG-rHuMGDF), a recombinant molecule related to thrombopoietin, specifically stimulates megakaryopoiesis and platelet production and reduces the severity of thrombocytopenia in animals receiving myelosuppressive chemotherapy. METHODS: We conducted a randomized, double-blind, placebo-controlled dose-escalation study of MGDF in 53 patients with lung cancer who were treated with carboplatin and paclitaxel. The patients were randomly assigned in blocks of 4 in a 1:3 ratio to receive either placebo or MGDF (0.03, 0.1, 0.3, 1.0, 3.0, or 5.0 microg per kilogram of body weight per day), injected subcutaneously. No other marrow-active cytokines were given. RESULTS: In the 38 patients who received MGDF after chemotherapy, the median nadir platelet count was 188,000 per cubic millimeter (range, 68,000 to 373,000), as compared with 111,000 per cubic millimeter (range, 21,000 to 307,000) in 12 patients receiving placebo (P = 0.013). The platelet count recovered to base-line levels in 14 days in the treated patients as compared with more than 21 days in those receiving placebo (P<0.001). Among all 40 patients treated with MGDF, 1 had deep venous thrombosis and pulmonary embolism, and another had superficial thrombophlebitis. CONCLUSIONS: MGDF has potent stimulatory effects on platelet production in patients with chemotherapy-induced thrombocytopenia.

Adult↗

PubMed2004

Platelet count, previous infection and FCGR2B genotype predict development of chronic disease in newly diagnosed idiopathic thrombocytopenia in childhood: results of a prospective study.

About 25-30% of children with acute idiopathic thrombocytopenia (ITP) develop chronic disease. It is not well known which patient characteristics influence the course of the ITP. A prospective study in 60 children with newly diagnosed ITP was performed. The aim of the study was to identify patient characteristics at the onset of thrombocytopenia that predicts the progression to chronic ITP. Clinical data and blood samples were collected at several time points during the first 6 months of the disease. Variables predicting chronic disease, as calculated in a multivariate logistic regression analysis, were a platelet count >10 x 10(9)/l at the onset [odds ratio (OR) 1.1, 95% confidence interval (CI) 1.01-1.14], the absence of infection shortly before the onset of the disease (OR 4.8, CI 1.16-19.57) and FGR2B-232I/T genotype (OR 7.9, CI 0.96-65.27). The latter may point at an immune-modulating role of Fc gamma RIIb in ITP. Although only three patients had serious bleeds, 35 patients received immune-modulating treatment for low platelet counts only. Seventeen patients were treated with intravenous immunoglobulin (IVIG) and 18 patients received corticosteroids. Patient variables did not differ between these treatment groups. However, patients receiving IVIG had significantly lower risk for chronic disease.

Adolescent↗

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↗

PubMed1964