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Fulltext Trends of platelet inhibition in different clopidogrel pretreatment patterns in malaysian patients undergoing elective percutaneous coronary intervention

Tiong WN, Mejin M, Fong AY, Wee CC, Lai LY, Hwang SS, et al.

Med J Malaysia, 2013 Aug;68(4):326-31.
PMID: 24145261 MyJurnal
Matched MeSH terms: Blood Platelets*
Fulltext Assessment of quality of platelets preserved in plasma and platelet additive solution: A Malaysian experience

Mokhtar MB, Hashim HB, Joshi SR

Asian J Transfus Sci, 2016 Jan-Jun;10(1):84-7.
PMID: 27011678 DOI: 10.4103/0973-6247.172177

A use of platelet additives solution (PAS) improves storage conditions so as to give increased shelf life to platelets and to maintain hemostatic function.

Matched MeSH terms: Blood Platelets
Fulltext In Vitro Cell Proliferation and Migration Properties of Oral Mucosal Fibroblasts: A Comparative Study on the Effects of Cord Blood- and Peripheral Blood-Platelet Lysate

Azmi AF, Yahya MAAM, Azhar NA, Ibrahim N, Ghafar NA, Ghani NAA, et al.

Int J Mol Sci, 2023 Mar 17;24(6).
PMID: 36982842 DOI: 10.3390/ijms24065775

Cord blood-platelet lysate (CB-PL), containing growth factors such as a platelet-derived growth factor, has a similar efficacy to peripheral blood-platelet lysate (PB-PL) in initiating cell growth and differentiation, which makes it a unique alternative to be implemented into oral ulceration healing. This research study aimed to compare the effectiveness of CB-PL and PB-PL in promoting oral wound closure in vitro. Alamar blue assay was used to determine the optimal concentration of CB-PL and PB-PL in enhancing the proliferation of human oral mucosal fibroblasts (HOMF). The percentage of wound closure was measured using the wound-healing assay for CB-PL and PB-PL at the optimal concentration of 1.25% and 0.3125%, respectively. The gene expressions of cell phenotypic makers (Col. I, Col. III, elastin and fibronectin) were determined via qRT-PCR. The concentrations of PDGF-BB were quantified using ELISA. We found that CB-PL was as effective as PB-PL in promoting wound-healing and both PL were more effective compared to the control (CTRL) group in accelerating the cell migration in the wound-healing assay. The gene expressions of Col. III and fibronectin were significantly higher in PB-PL compared to CB-PL. The PDGF-BB concentration of PB-PL was the highest and it decreased after the wound closed on day 3. Therefore, we concluded that PL from both sources can be a beneficial treatment for wound-healing, but PB-PL showed the most promising wound-healing properties in this study.

Matched MeSH terms: Blood Platelets/metabolism
Prophylactic platelet transfusion plus supportive care versus supportive care alone in adults with dengue and thrombocytopenia: a multicentre, open-label, randomised, superiority trial

Lye DC, Archuleta S, Syed-Omar SF, Low JG, Oh HM, Wei Y, et al.

Lancet, 2017 Apr 22;389(10079):1611-1618.
PMID: 28283286 DOI: 10.1016/S0140-6736(17)30269-6

BACKGROUND: Dengue is the commonest vector-borne infection worldwide. It is often associated with thrombocytopenia, and prophylactic platelet transfusion is widely used despite the dearth of robust evidence. We aimed to assess the efficacy and safety of prophylactic platelet transfusion in the prevention of bleeding in adults with dengue and thrombocytopenia.
METHODS: We did an open-label, randomised, superiority trial in five hospitals in Singapore and Malaysia. We recruited patients aged at least 21 years who had laboratory-confirmed dengue (confirmed or probable) and thrombocytopenia (≤20 000 platelets per μL), without persistent mild bleeding or any severe bleeding. Patients were assigned (1:1), with randomly permuted block sizes of four or six and stratified by centre, to receive prophylactic platelet transfusion in addition to supportive care (transfusion group) or supportive care alone (control group). In the transfusion group, 4 units of pooled platelets were given each day when platelet count was 20 000 per μL or lower; supportive care consisted of bed rest, fluid therapy, and fever and pain medications. The primary endpoint was clinical bleeding (excluding petechiae) by study day 7 or hospital discharge (whichever was earlier), analysed by intention to treat. Safety outcomes were analysed according to the actual treatment received. This study was registered with ClinicalTrials.gov, number NCT01030211, and is completed.
FINDINGS: Between April 29, 2010, and Dec 9, 2014, we randomly assigned 372 patients to the transfusion group (n=188) or the control group (n=184). The intention-to-treat analysis included 187 patients in the transfusion group (one patient was withdrawn immediately) and 182 in the control group (one was withdrawn immediately and one did not have confirmed or probable dengue). Clinical bleeding by day 7 or hospital discharge occurred in 40 (21%) patients in the transfusion group and 48 (26%) patients in the control group (risk difference -4·98% [95% CI -15·08 to 5·34]; relative risk 0·81 [95% CI 0·56 to 1·17]; p=0·16). 13 adverse events occurred in the transfusion group and two occurred in the control group (5·81% [-4·42 to 16·01]; 6·26 [1·43 to 27·34]; p=0·0064). Adverse events that were possibly, probably, or definitely related to transfusion included three cases of urticaria, one maculopapular rash, one pruritus, and one chest pain, as well as one case each of anaphylaxis, transfusion-related acute lung injury, and fluid overload that resulted in serious adverse events. No death was reported.
INTERPRETATION: In adult patients with dengue and thrombocytopenia, prophylactic platelet transfusion was not superior to supportive care in preventing bleeding, and might be associated with adverse events.
FUNDING: National Medical Research Council, Singapore.
Study site: Hospitals, Singapore; University Malaya Medical Centre (UMMC). Kuala Lumpur, Malaysia
Study protocol: https://clinicaltrials.gov/ct2/show/NCT01030211

Matched MeSH terms: Blood Platelets*
Fulltext Detection of antiplatelet antibodies in patients with idiopathic thrombocytopenic purpura (ITP) by immunofluorescence

Pereira RA, Bosco J, Pang T

Singapore Med J, 1981 Aug;22(4):203-C.
PMID: 7034209

An immunofluorescence test (IFT) using platelet suspensions was used to detect the presence of serum anti-platelet antibodies (APA) in the sera of Malaysian patients with idiopathic thrombocytopenic purpura. Of the 28 patients tested, 19 (or 68%) had detectable APA with percentage platelet fluorescence ranging from 34% - 80% (mean 51% +/- 10). Normal sera gave fluorescence values of 6 - 15% (mean 9% +/- 5). Sera from patients with SLE, thyrotoxicosis and dengue haemorrhagic fever gave mean values of 29%, 8% and 9% respectively. Additionally, no apparent correlation was observed between percentage platelet fluorescence and the severity of thrombocytopenia. The importance and significance of these findings are discussed.

Matched MeSH terms: Blood Platelets/immunology*
The role of peripheral blood smear examination in the evaluation of suspected platelet-related disorders in children: A practical approach and an illustrated review

Tyrrell L, Scruggs M, Kerwin A, Kahwash SB

Malays J Pathol, 2022 Dec;44(3):397-413.
PMID: 36591709

Platelets, along with coagulation factors and vasculature, represent the three main compartments of hemostasis. Upon investigation of a suspected hemostasis disorder, platelet count, size and morphology often offer important clues to the diagnosis or help narrow the differential diagnosis. In this review, we describe a general approach to diagnosing platelet disorders, starting with easily obtained data such as findings of complete blood count (CBC) and microscopic review of a stained peripheral blood smear. We discuss general findings that help separate consumptive from underproduction thrombocytopenia. We further touch on inherited thrombocytopenia disorders after classifying them into those associated with small, normal sized or large platelets. Illustrative microscopic images are provided where contributory. We conclude with a suggested algorithmic step-by-step approach to investigating a suspected platelet disorder in children.

Matched MeSH terms: Blood Platelets
Liquid biopsy in breast carcinoma: Are we there yet?

Wijesinghe HD, Lokuhetty MDS

Malays J Pathol, 2023 Aug;45(2):175-186.
PMID: 37658527

Breast carcinoma is the most common malignancy among women worldwide. Liquid biopsy is a method of obtaining tumour-derived material from blood and body fluid. This includes the assessment of circulating tumour cells (CTCs), circulating tumour deoxyribose nucleic acid (ctDNA), tumour educated platelets (TEPs) and exosomes. Detection of CTCs and ctDNA in liquid biopsy has been shown to have prognostic and predictive value in both early and metastatic breast carcinoma. The study of CTCs could also advance our understanding of aspects of tumour biology, including epithelial mesenchymal transition. ctDNA can be used to assess and monitor the molecular profile of breast carcinoma. It may help detect new genetic alterations in tumours and predict disease progression before the onset of clinical features or radiological evidence. TEPs and exosomes are also emerging as diagnostic, prognostic and predictive markers of breast carcinoma. Thus, liquid biopsy provides a non-invasive, repeatable method for the dynamic assessment of the tumour. Many methods have been used for the detection of CTCs and ctDNA. Most of these are still in the research stage and only the CellSearch method for the detection of CTCs and Therascreen PIK3CA RGQ polymerase chain reaction (PCR) assay for the detection of PIK3CA (Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha) mutations in liquid biopsy have approval of the United States, Food and Drug Administration. However, their high costs, lack of standardized procedures, and a long and complicated detection process have limited their use. Despite its limitations, liquid biopsy is a useful tool in clinical decision making and has the potential to play an increasingly important role in the management of breast carcinoma in the future as we move toward more personalized cancer care.

Matched MeSH terms: Blood Platelets
Fulltext Platelet rich concentrate promotes early cellular proliferation and multiple lineage differentiation of human mesenchymal stromal cells in vitro

Shani S, Ahmad RE, Naveen SV, Murali MR, Puvanan K, Abbas AA, et al.

ScientificWorldJournal, 2014;2014:845293.
PMID: 25436230 DOI: 10.1155/2014/845293

Platelet rich concentrate (PRC) is a natural adjuvant that aids in human mesenchymal stromal cell (hMSC) proliferation in vitro; however, its role requires further exploration. This study was conducted to determine the optimal concentration of PRC required for achieving the maximal proliferation, and the need for activating the platelets to achieve this effect, and if PRC could independently induce early differentiation of hMSC. The gene expression of markers for osteocytes (ALP, RUNX2), chondrocytes (SOX9, COL2A1), and adipocytes (PPAR-γ) was determined at each time point in hMSC treated with 15% activated and nonactivated PRC since maximal proliferative effect was achieved at this concentration. The isolated PRC had approximately fourfold higher platelet count than whole blood. There was no significant difference in hMSC proliferation between the activated and nonactivated PRC. Only RUNX2 and SOX9 genes were upregulated throughout the 8 days. However, protein expression study showed formation of oil globules from day 4, significant increase in ALP at days 6 and 8 (P ≤ 0.05), and increased glycosaminoglycan levels at all time points (P < 0.05), suggesting the early differentiation of hMSC into osteogenic and adipogenic lineages. This study demonstrates that the use of PRC increased hMSC proliferation and induced early differentiation of hMSC into multiple mesenchymal lineages, without preactivation or addition of differentiation medium.

Matched MeSH terms: Blood Platelets/physiology*
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 Effectiveness of Autologous Platelet Concentrates in Management of Young Immature Necrotic Permanent Teeth-A Systematic Review and Meta-Analysis

Panda S, Mishra L, Arbildo-Vega HI, Lapinska B, Lukomska-Szymanska M, Khijmatgar S, et al.

Cells, 2020 10 07;9(10).
PMID: 33036462 DOI: 10.3390/cells9102241

The use of autologous platelet concentrates (APCs) in regenerative endodontic procedures is inconsistent and unclear. The aim of this meta-analysis was to evaluate the effectiveness of autologous platelet concentrates compared to traditional blood-clot regeneration for the management of young, immature, necrotic, permanent teeth. The digital databases MEDLINE, SCOPUS, CENTRAL, Web of Science, and EMBASE were searched to identify ten randomized clinical trials. The outcomes at postoperative follow-up, such as dentinal wall thickness (DWT), increase in root length (RL), calcific barrier formation (CB), apical closure (AC), vitality response (VR), and success rate (SR), were subjected to both qualitative synthesis and quantitative meta-analysis. The meta-analysis showed that APCs significantly improved apical closure (risk ratio (RR) = 1.17; 95% CI: 1.01, 1.37; p = 0.04) and response to vitality pulp tests (RR = 1.61; 95% CI: 1.03, 2.52; p = 0.04), whereas no significant effect was observed on root lengthening, dentin wall thickness, or success rate of immature, necrotic teeth treated with regenerative endodontics. APCs could be beneficial when treating young, immature, necrotic, permanent teeth regarding better apical closure and improved response to vitality tests.

Matched MeSH terms: Blood Platelets/metabolism
Coagulation of Malays and caucasians: a comparative study of two groups of young soldiers

Loncin H

Med J Malaya, 1965 Sep;20(1):85-7.
PMID: 4221440
Matched MeSH terms: Blood Platelets*
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 Coexistence of CACNA1A, ATP1A2, and KCNN3 gene mutation in migraine patients with human platelet polymorphism

Bhaskar S, Abdullah JM, Ghazali MM

Neurosciences (Riyadh), 2008 Oct;13(4):356-8.
PMID: 21063360

OBJECTIVE: To look for any possible coexistence of CACNA1A, ATP1A2, and KCNN3 gene mutations in migraine patients who had human platelet HPA-1a/1b polymorphism, which is also known as PlA1/A2 polymorphism.
METHODS: The study was carried out at the Neurology Clinic, Hospital University Sains Malaysia, Kelantan, Malaysia between April 2004 and March 2005. The DNA from 4 patients who had migraine with the HPA1a/1b polymorphism were analyzed by polymerase chain reaction using the allele specific oligonucleotide technique to detect the presence of CACNA1A, ATP1A2, and KCNN3 genotypes.
RESULTS: We found that the CACNA1A gene mutation alone was present in only one patient who presented with classical migraine with aura. The gene mutations on ATP1A2 and KCNN3 were seen in none of our 4 cases with migraine.
CONCLUSION: There is no coexistence between the platelet HPA-1a/1b polymorphism and the ATP1A2 and KCNN3 gene mutations, though one classical migraine patient with HPA-1a/1b polymorphism had the CACNA1A gene mutation. Larger studies are warranted to confirm these findings.
Study site: Neurology Clinic, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia

Matched MeSH terms: Blood Platelets
Fulltext Effect of ultrapure lipopolysaccharides derived from diverse bacterial species on the modulation of platelet activation

Vallance TM, Ravishankar D, Albadawi DAI, Layfield H, Sheard J, Vaiyapuri R, et al.

Sci Rep, 2019 12 03;9(1):18258.
PMID: 31796818 DOI: 10.1038/s41598-019-54617-w

Platelets are small circulating blood cells that play essential roles in the maintenance of haemostasis via blood clotting. However, they also play critical roles in the regulation of innate immune responses. Inflammatory receptors, specifically Toll-like receptor (TLR)-4, have been reported to modify platelet reactivity. A plethora of studies have reported controversial functions of TLR4 in the modulation of platelet function using various chemotypes and preparations of its ligand, lipopolysaccharide (LPS). The method of preparation of LPS may explain these discrepancies however this is not fully understood. Hence, to determine the impact of LPS on platelet activation, we used ultrapure preparations of LPS from Escherichia coli (LPSEC), Salmonella minnesota (LPSSM), and Rhodobacter sphaeroides (LPSRS) and examined their actions under diverse experimental conditions in human platelets. LPSEC did not affect platelet activation markers such as inside-out signalling to integrin αIIbβ3 or P-selectin exposure upon agonist-induced activation in platelet-rich plasma or whole blood whereas LPSSM and LPSRS inhibited platelet activation under specific conditions at supraphysiological concentrations. Overall, our data demonstrate that platelet activation is not largely influenced by any of the ultrapure LPS chemotypes used in this study on their own except under certain conditions.

Matched MeSH terms: Blood Platelets/drug effects; Blood Platelets/immunology; Blood Platelets/metabolism
Fulltext Evaluation of immature platelet fraction as a marker of dengue fever progression

Looi KW, Matsui Y, Kono M, Samudi C, Kojima N, Ong JX, et al.

Int J Infect Dis, 2021 Sep;110:187-194.
PMID: 34302960 DOI: 10.1016/j.ijid.2021.07.048

OBJECTIVES: Progression of dengue is often associated with thrombocytopenia resulting from viral-induced bone marrow suppression and immune-mediated peripheral platelet consumption. Immature platelet fraction (IPF), which can be measured using a haematology analyser, is a precursor indicating platelet formation in the bone marrow. This study evaluated the trend of IPF as an early recovery indicator of platelets in dengue patients with thrombocytopenia, and its relationship with severe dengue in conjunction with reticulocyte count.
METHODS: Hospitalized patients with dengue were enrolled and followed-up daily until discharge. Blood investigations included daily full blood counts and IPF measured using a haematology analyser.
RESULTS: In total, 287 patients with confirmed dengue were enrolled in this study, 25 of whom had severe dengue. All patients had a decreasing trend in platelet count in the first week of illness, concomitant with an increasing trend in the percentage of immature platelets to total platelets (IPF%) for more than 3 days prior to platelet recovery. IPF% was significantly increased in patients with severe dengue compared with patients with non-severe dengue on days 3-5 after the onset of fever. Reticulocyte count increased significantly in patients with severe dengue on day 5.
CONCLUSIONS: IPF can be utilized as an early recovery indicator of platelets in patients with dengue and thrombocytopenia.

Matched MeSH terms: Blood Platelets
Fulltext Platelet Alloantibody in Multiply Transfused Thrombocytopenic Patients

Wan Haslindawani Wan Mahmood, Rapiaah Mustaffa

International Medical Journal Malaysia, 2007;6(2):1-10.
MyJurnal

Introduction: Multiply transfused patients are frequently subjected to platelet alloimmunization. These platelet alloantibodies produced can result in refractoriness to platelet transfusion. Material and Methods: Ninety five thrombocytopenic (platelet count

Matched MeSH terms: Blood Platelets
Fulltext Routine blood parameters of dengue infected children and adults. A meta-analysis

Low GK, Jiee SF, Masilamani R, Shanmuganathan S, Rai P, Manda M, et al.

Pathog Glob Health, 2023 Sep;117(6):565-589.
PMID: 36593636 DOI: 10.1080/20477724.2022.2161864

The World Health Organization (WHO) has revised dengue case classification in 2009 to better reflect the severity of the disease. However, there was no comprehensive meta-analysis of pooled routine blood parameters according to the age or the categories of the 2009 WHO classification. This study aimed to meta-analyze the routine blood parameters of dengue infected children and adults. Electronic search was performed with eligible articles included for review. Meta-analysis was conducted for six blood parameters stratified into children, adults and all ages, which were further grouped into the three 2009 WHO case classifications (dengue without warning signs, DwoWS; dengue with warning signs, DwWS; severe dengue, SD), non-severe dengue (non-SD) and 'All' cases. A total of 55 articles were included in the meta-analysis. Fifteen studies were conducted in the children's age category, 31 studies in the adult category and nine studies in all ages. The four selected pooled blood parameters for children were white blood cell (WBC) (×103/L) with 5.11 (SD), 5.64 (DwWS), 5.52 (DwoWS) and 4.68 (Non-SD) hematocrit (HCT) (%) with 36.78 (SD), 40.70 (DwWS), 35.00 (DwoWS) and 29.78 (Non-SD) platelet (PLT) (×103/µL) with 78.66 (SD), 108.01 (DwWS), 153.47 (DwoWS) and 108.29 (non-SD); and aspartate aminotransferase (AST) (/µL) with 248.88 (SD), 170.83 (DwWS), 83.24 (DwoWS) and 102.99 (non-SD). For adult, WBC were 4.96 (SD), 6.44 (DwWS), 7.74 (DwoWS) and 3.61 (non-SD); HCT were 39.50 (SD), 39.00 (DwWS), 37.45 (DwoWS) and 41.68 (non-SD); PLT were 49.62 (SD), 96.60 (DwWS), 114.37 (DwoWS) and 71.13 (non-SD); and AST were 399.50 (SD), 141.01 (DwWS), 96.19 (DwoWS) and 118.13 (non-SD). These blood parameters could not differentiate between each dengue severity according to the WHO 2009 classification, SD, DwoWS, DwWS and non-SD, because the timing of blood drawing was not known and there was an overlapping confidence interval among the clinical classification. Hence, these pooled blood parameter values could not be used to guide clinicians in management and did not correlate with severity as in previous scientific literatures and guidelines.

Matched MeSH terms: Blood Platelets
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/drug effects*; Blood Platelets/pathology
Fulltext Inhibition of Human Platelet Aggregation and Low-Density Lipoprotein Oxidation by Premna foetida Extract and Its Major Compounds

Dianita R, Jantan I

Molecules, 2019 Apr 13;24(8).
PMID: 31013947 DOI: 10.3390/molecules24081469

Many Premna species have been used in traditional medicine to treat hypertension and cardiac insufficiency, and as a tonic for cardiac-related problems. Some have been reported to possess cardiovascular protective activity through several possible mechanisms, but not Premna foetida. In the present study, the methanol extract of P. foetida leaves (PFM) and its isolated compounds were evaluated for their ability to inhibit copper-mediated human low-density lipoprotein (LDL) oxidation and arachidonic acid (AA)- and adenosine diphosphate (ADP)-induced platelet aggregation. Six flavonoids, three triterpenoids, vanillic acid and stigmasterol were successfully isolated from PFM. Of the isolated compounds, quercetin was the most active against LDL oxidation (IC50 4.25 µM). The flavonols were more active than the flavones against LDL oxidation, suggesting that hydroxyl group at C-3 and the catechol moiety at B-ring may play important roles in protecting LDL from oxidation. Most tested flavonoids showed stronger inhibition towards AA-induced than the ADP-induced platelet aggregation with apigenin exhibiting the strongest effect (IC50 52.3 and 127.4 µM, respectively) while quercetin and kaempferol showed moderate activity. The results suggested that flavonoids, especially quercetin, apigenin and kaempferol were among the major constituents of P. foetida responsible for anti-LDL oxidation and anti-platelet aggregation.

Matched MeSH terms: Blood Platelets/cytology; Blood Platelets/metabolism*
Thrombocyte counts in mice after the administration of papaya leaf suspension

Sathasivam K, Ramanathan S, Mansor SM, Haris MR, Wernsdorfer WH

Wien Klin Wochenschr, 2009 Oct;121 Suppl 3:19-22.
PMID: 19915811 DOI: 10.1007/s00508-009-1229-0

Following up a popular use of crude leaf preparations from Carica papaya for the treatment of dengue infections, a suspension of powdered Carica papaya leaves in palm oil has been investigated for its effect on thrombocyte counts in mice, administering by gavage 15 mg of powdered leaves per kg body weight to 5 mice. Equal numbers of animals received corresponding volumes of either palm oil alone or physiological saline solution. Thrombocyte counts before and at 1, 2, 4, 8, 10, 12, 24, 48 and 72 hours after dosing revealed significantly higher mean counts at 1, 2, 4, 8, 10 and 12 after dosing with the C. papaya leaf formulation as compared to the mean count at hour 0. There was only a non-significant rise of thrombocyte counts in the group having received saline solution, possibly the expression of a normal circadian rhythm in mice. The group having received palm oil only showed a protracted increase of platelet counts that was significant at hours 8 and 48 and obviously the result of a hitherto unknown stimulation of thrombocyte release. The results call for a dose-response investigation and for extending the studies to the isolation and identification of the C. papaya substances responsible for the release and/or production of thrombocytes.

Matched MeSH terms: Blood Platelets/cytology*; Blood Platelets/drug effects*

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