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Fulltext Utility of pre-treatment neutrophil-lymphocyte ratio and platelet-lymphocyte ratio as prognostic factors in breast cancer

Koh CH, Bhoo-Pathy N, Ng KL, Jabir RS, Tan GH, See MH, et al.

Br. J. Cancer, 2015 Jun 30;113(1):150-8.
PMID: 26022929 DOI: 10.1038/bjc.2015.183

Peripheral blood-derived inflammation-based scores such as the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) have recently been proposed as prognostic markers in solid tumours. Although evidence to support these markers as unfavourable prognostic factors is more compelling in gastrointestinal cancers, very little is known of their impact on breast cancer. We investigated the association between the NLR and PLR, and overall survival after breast cancer.

Matched MeSH terms: Blood Platelets/pathology*
Fulltext Plasma-derived microparticles in polycythaemia vera

Ahadon M, Abdul Aziz S, Wong CL, Leong CF

Malays J Pathol, 2018 Apr;40(1):41-48.
PMID: 29704383 MyJurnal

INTRODUCTION: Microparticles are membrane bound vesicles, measuring less than 1.0 um, which are released during cellular activation or during apoptosis. Studies have shown that these circulating microparticles play a role in coagulation, cell signaling and cellular interactions. Increased levels of circulating microparticles have been observed in a number of conditions where there is vascular dysfunction, thrombosis and inflammation. The objective of this study was to determine the various plasma-derived microparticles in patients with polycythaemia vera (PV) in Universiti Kebangsaan Malaysia Medical Centre and to compare them with normal control.
METHODS: A total of 15 patients with PV and 15 healthy volunteers were included in this cross-sectional descriptive study. Plasma samples from both patients and healthy volunteers were prepared and further processed for isolation of microparticles. Flow cytometry analyses were then carried out in all samples to determine the cellular origin of the microparticles. Full blood count parameters for both groups were also collected. Data collected were analyzed using SPSS version 12.0.
RESULTS: Patients with PV had a significantly higher percentage of platelet derived microparticles compared to healthy controls (P <0.05). The control group had a higher level of endothelial derived microparticles but the differences were not statistically significant (P > 0.05).
CONCLUSION: The median percentage of positive events for platelet derived microparticles was higher in patients with PV compared to normal healthy controls.

Matched MeSH terms: Blood Platelets/pathology
Fulltext Effect of pyridostigmine (Mestinon) on human platelet aggregation

Leong CF, Aini-Ardena M, Cheong SK, Norris N

Malays J Pathol, 2009 Jun;31(1):45-52.
PMID: 19694313 MyJurnal

Normal platelet functions are critical for achieving primary haemostasis. Numerous medications have been shown to affect platelet functions. Pyridostigmine (Mestinon), an orally active cholinesterase inhibitor that is commonly used to treat myasthenia gravis has been documented to cause epistaxis and prolonged bleeding after a cut in anectodal reports. This study was initiated after a patient diagnosed to have myasthenia gravis, developed multiple bruises a week after being started on Mestinon. The objective of this study was to investigate the effect of Mestinon on platelet aggregation stimulated with various agonists in vitro.

Matched MeSH terms: Blood Platelets/pathology
Risk factors and clinical outcome of profound thrombocytopenia in adult patients with DENV infections

Dhanoa A, Rajasekaram G, Hassan SS, Ramadas A, Azreen Adnan NA, Lau CF, et al.

Platelets, 2017 Nov;28(7):724-727.
PMID: 28287000 DOI: 10.1080/09537104.2017.1293802

Severe thrombocytopenia is common in dengue virus (DENV) infections. However, studies focusing on the role of profound thrombocytopenia (PT) (nadir platelet counts ≤ 20 000/mm3) in DENV infections are scarce. This study aims to identify the associated features and outcome of DENV patients with PT. It involves 237 adult hospitalized patients who were DENV PCR positive. The presence of comorbidity (AOR = 4.625; 95% CI = 1.113-19.230), higher admission hematocrit (AOR = 1.213; 95% CI = 1.067-1.379), lower admission albumin (AOR = 0.870; 95% CI = 0.766-0.988) and lower admission platelets (AOR = 0.980; 95% CI = 0.969-0.991) was associated with platelets ≤ 20 000/mm3 in multivariate logistic regression. PT was not affected by DENV serotypes, coinfections and secondary DENV infections. Patients with PT had significantly higher risk of experiencing warning signs (AOR = 3.709, 95% CI = 1.089-12.634) and longer hospital stay (AOR = 1.943, 95% CI = 1.010-3.774). However, severe dengue disease, hemorrhagic manifestations and need for intensive care were not significantly associated with PT.

Matched MeSH terms: Blood Platelets/pathology*
Fulltext Platelets kill circulating parasites of all major Plasmodium species in human malaria

Kho S, Barber BE, Johar E, Andries B, Poespoprodjo JR, Kenangalem E, et al.

Blood, 2018 Sep 20;132(12):1332-1344.
PMID: 30026183 DOI: 10.1182/blood-2018-05-849307

Platelets are understood to assist host innate immune responses against infection, although direct evidence of this function in any human disease, including malaria, is unknown. Here we characterized platelet-erythrocyte interactions by microscopy and flow cytometry in patients with malaria naturally infected with Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, or Plasmodium knowlesi Blood samples from 376 participants were collected from malaria-endemic areas of Papua, Indonesia, and Sabah, Malaysia. Platelets were observed binding directly with and killing intraerythrocytic parasites of each of the Plasmodium species studied, particularly mature stages, and was greatest in P vivax patients. Platelets preferentially bound to the infected more than to the uninfected erythrocytes in the bloodstream. Analysis of intraerythrocytic parasites indicated the frequent occurrence of platelet-associated parasite killing, characterized by the intraerythrocytic accumulation of platelet factor-4 and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling of parasite nuclei (PF4+TUNEL+ parasites). These PF4+TUNEL+ parasites were not associated with measures of systemic platelet activation. Importantly, patient platelet counts, infected erythrocyte-platelet complexes, and platelet-associated parasite killing correlated inversely with patient parasite loads. These relationships, taken together with the frequency of platelet-associated parasite killing observed among the different patients and Plasmodium species, suggest that platelets may control the growth of between 5% and 60% of circulating parasites. Platelet-erythrocyte complexes made up a major proportion of the total platelet pool in patients with malaria and may therefore contribute considerably to malarial thrombocytopenia. Parasite killing was demonstrated to be platelet factor-4-mediated in P knowlesi culture. Collectively, our results indicate that platelets directly contribute to innate control of Plasmodium infection in human malaria.

Matched MeSH terms: Blood Platelets/pathology
Increased PAC-1 expression among patients with multiple myeloma on concurrent thalidomide and warfarin

Abdullah WZ, Roshan TM, Hussin A, Zain WS, Abdullah D

Blood Coagul Fibrinolysis, 2013 Dec;24(8):893-5.
PMID: 24030118 DOI: 10.1097/MBC.0b013e3283642ee2

Treatment with thalidomide is associated with vascular thrombosis. The effect of thalidomide on platelet activation is unclear, although the use of aspirin is justified for thromboprophylaxis. A study on platelet activation markers was done among multiple myeloma patients receiving thalidomide therapy with warfarin as thromboprophylaxis. Strict criteria and procedure were set to avoid misinterpretation of platelet activation other than due to the thalidomide's effect. Blood specimen pre and post thalidomide therapy were used for flow cytometric analysis. Platelet surface P-selectin, CD62P expression and PAC-1 (antibody that recognizes conformational change of the GPIIb/IIIa complex) were examined by using three-colour flowcytometer. Increased expression marker for PAC-1 was observed after 4 weeks of thalidomide treatment (P

Matched MeSH terms: Blood Platelets/pathology
Anticoagulation Therapy in Patients with Chronic Kidney Disease

Saheb Sharif-Askari F, Syed Sulaiman SA, Saheb Sharif-Askari N

Adv Exp Med Biol, 2017;906:101-114.
PMID: 27628006

Patients with chronic kidney disease (CKD) are at increased risk for both thrombotic events and bleeding. The early stages of CKD are mainly associated with prothrombotic tendency, whereas in its more advanced stages, beside the prothrombotic state, platelets can become dysfunctional due to uremic-related toxin exposure leading to an increased bleeding tendency. Patients with CKD usually require anticoagulation therapy for treatment or prevention of thromboembolic diseases. However, this benefit could easily be offset by the risk of anticoagulant-induced bleeding. Treatment of patients with CKD should be based on evidence from randomized clinical trials, but usually CKD patients are excluded from these trials. In the past, unfractionated heparins were the anticoagulant of choice for patients with CKD because of its independence of kidney elimination. However, currently low-molecular-weight heparins have largely replaced the use of unfractionated heparins owing to fewer incidences of heparin-induced thrombocytopenia and bleeding. We undertook this review in order to explain the practical considerations for the management of anticoagulation in these high risk population.

Matched MeSH terms: Blood Platelets/pathology