Displaying publications 2421 - 2440 of 5566 in total

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  1. Lee SM, Wong WP, Hiong KC, Loong AM, Chew SF, Ip YK
    J. Exp. Zoolog. Part A Comp. Exp. Biol., 2006 Dec 1;305(12):995-1009.
    PMID: 17068799
    This study aimed to determine effects of 6-day progressive increase in salinity from 1 per thousand to 15 per thousand on nitrogen metabolism and excretion in the soft-shelled turtle, Pelodiscus sinensis. For turtles exposed to 15 per thousand water on day 6, the plasma osmolality and concentrations of Na+, Cl- and urea increased significantly, which presumably decreased the osmotic loss of water. Simultaneously, there were significant increases in contents of urea, certain free amino acids (FAAs) and water-soluble proteins that were involved in cell volume regulation in various tissues. There was an apparent increase in proteolysis, releasing FAAs as osmolytes. In addition, there might be an increase in catabolism of certain amino acids, producing more ammonia. The excess ammonia was retained as indicated by a significant decrease in the rate of ammonia excretion on day 4 in 15 per thousand water, and a major portion of it was converted to urea. The rate of urea synthesis increased 1.4-fold during the 6-day period, although the capacity of the hepatic ornithine urea cycle remained unchanged. Urea was retained for osmoregulation because there was a significant decrease in urea excretion on day 4. Increased protein degradation and urea synthesis implies greater metabolic demands, and indeed turtles exposed to 15 per thousand water had significantly higher O2 consumption rate than the freshwater (FW) control. When turtles were returned from 15 per thousand water to FW on day 7, there were significant increases in ammonia (probably released through increased amino acid catabolism) and urea excretion, confirming that FAAs and urea were retained for osmoregulatory purposes in brackish water.
    Matched MeSH terms: Amino Acids/blood; Blood Chemical Analysis
  2. Inayat-Hussain SH, Lubis SH, Sakian NI, Ghazali AR, Ali NS, El Sersi M, et al.
    Toxicol Appl Pharmacol, 2007 Mar;219(2-3):210-6.
    PMID: 17140616
    A cross-sectional study was conducted to investigate the effects of acute and chronic pesticide exposure on the plasma beta-glucuronidase enzyme activity among five patients of acute pesticide poisoning in Tengku Ampuan Rahimah Hospital, Klang, 230 farmers in the MADA area, Kedah and 49 fishermen in Setiu, Terengganu. The duration of pesticide exposure among the patients was unknown, but the plasma samples from patients were collected on day one in the hospital. The duration of pesticide exposure among the farmers was between 1 and 45 years. The beta-glucuronidase activity was compared with plasma cholinesterase activity in the same individual. The plasma cholinesterase activity was measured using Cholinesterase (PTC) Reagent set kit (Teco Diagnostics, UK) based on colorimetric method, while the plasma beta-glucuronidase activity was measured fluorometrically based on beta-glucuronidase assay. The plasma cholinesterase activity was significantly reduced (p<0.05) among the patients (1386.786+/-791.291 U/L/min) but the inhibition in plasma cholinesterase activity among the farmers (7346.5+/-1860.786 U/L/min) was not significant (p>0.05). The plasma beta-glucuronidase activity among the farmers was significantly elevated (p<0.05) (0.737+/-0.425 microM/h) but not significant among the patients (p>0.05). The plasma cholinesterase activity was positively correlated with the plasma beta-glucuronidase activity among the farmers (r=0.205, p<0.01) but not among the patients (r=0.79, p>0.05). Thus, plasma beta-glucuronidase enzyme activity can be measured as a biomarker for the chronic exposure of pesticide. However, further studies need to be performed to confirm whether plasma beta-glucuronidase can be a sensitive biomarker for anticholinesterase pesticide poisoning.
    Matched MeSH terms: Glucuronidase/blood*; Biomarkers/blood
  3. Hassan R, Abdullah WZ, Nik Hussain NH
    PMID: 16438162
    The purpose of this study was to detect the frequency of iron deficiency anemia in women attending their first antenatal clinic at a Maternal and Child Health Clinic in Kubang Kerian, a district of Kelantan that is located on the East coast of Malaysia. A cross-sectional study was done over a two-month period and fifty-two Malay women were enrolled in this study. Red blood cell indices and serum ferritin were used as a screening tool for anemia and iron status. Eighteen patients (34.6%) were anemic. The majority were classified as having mild anemia (90%). Four of them had hypochromic microcytic anemia. Of 52 women, 7 had iron deficient erythropoiesis and 11 (61.1%) had iron deficient anemia. The prevalence of iron deficiency anemia in pregnant women was 21.2%, which is similar to other developing countries. The serum ferritin level was significantly associated with the hemoglobin level (p=0.003). Other red blood cell indices were not useful in predicting iron deficient erythropoiesis. It is important to detect iron deficient erythropoiesis during the first antenatal check-up, as it is an early manifestation of iron deficiency anemia. In conclusion, screening for iron deficient is recommended during first antenatal visit because iron deficiency anemia is still the leading cause of nutritional deficiency in pregnant women. This will initiate an early therapeutic intervention so as to reduce public health problem.
    Study site: Hopital Universiti Sains Malaysia (HUSM) and the Maternal and Child Health Clinic, Kubang Kerian, Kelantan, Malaysia
    Matched MeSH terms: Pregnancy Complications, Hematologic/blood; Anemia, Iron-Deficiency/blood
  4. Fernandez SH
    Malays J Pathol, 2000 Jun;22(1):25-9.
    PMID: 16329534
    A 26-year-old Indian lady was admitted for lower abdominal pain, diarrhoea, vomiting, fever and cough. The initial diagnosis was that of peritonitis secondary to ruptured or perforated viscus with lobar pneumonia. On laparotomy, she was found to have necrotizing or Kikuchi's lymphadenitis of the abdominal lymph nodes. The initial two antinuclear antibody (ANA) results came back negative. She was diagnosed to have systemic lupus erythematosus (SLE) when the third sample for ANA came back positive and the double-stranded DNA (dsDNA) antibody test was homogenously positive. This case illustrates a need to be aware that necrotizing lymphadenitis can precede the onset of systemic lupus erythematosus.
    Matched MeSH terms: Antibodies, Antinuclear/blood; Lupus Erythematosus, Systemic/blood
  5. Lal S, Madhavan M, Heng CK
    Ann. Hum. Genet., 2005 Nov;69(Pt 6):639-44.
    PMID: 16266403
    Mitochondria are eukaryotic cytoplasmic organelles responsible for oxidative phosphorylation. The C to A nucleotide transversion in the NADH dehydrogenase subunit 2 (MT-ND2) coding region of mitochondrial DNA has been reported to be associated with plasma lipid levels, adult onset diseases and longevity. We have examined the role of this polymorphism in relation to plasma lipid levels and age in a total of 713 healthy individuals belonging to 3 ethnic groups in Singapore. The frequency of the A allele was significantly higher (p < 0.05) among the Chinese (0.15) in comparison to the Malays (0.05) and Indians (0.02). No significant difference in the frequency of the allele was observed between healthy and coronary artery disease subjects, and between age-stratified subjects. We found that the polymorphism is significantly associated in an ethnic- and gender-specific manner with plasma apoB levels in the Chinese males (p < 0.05). This is the first epidemiological report of the mt5178 C > A polymorphism and its association with plasma lipid levels in Asian populations outside Japan.
    Matched MeSH terms: Coronary Disease/blood*; Lipids/blood*
  6. Wong WK, Tan ZN, Othman N, Lim BH, Mohamed Z, Olivos Garcia A, et al.
    Clin Vaccine Immunol, 2011 Nov;18(11):1913-7.
    PMID: 21918120 DOI: 10.1128/CVI.05356-11
    Serodiagnosis of amoebiasis remains the preferred method for diagnosis of amoebic liver abscess (ALA). However, the commercially available kits are problematic in areas of endemicity due to the persistently high background antibody titers. Human serum samples (n = 38) from patients with ALA who live in areas of endemicity were collected from Hospital Universiti Sains Malaysia during the period of 2008 to 2010. Western blots using excretory-secretory antigen (ESA) collected from axenically grown Entamoeba histolytica were probed with the above serum samples. Seven antigenic proteins of ESA with various reactivities were identified, i.e., 152 kDa, 131 kDa, 123 kDa, 110 kDa, 100 kDa, 82 kDa, and 76 kDa. However, only the 152-kDa and 110-kDa proteins showed sensitivities above 80% in the Western blot analysis. All the antigenic proteins showed undetectable cross-reactivity when probed with healthy human serum samples (n = 30) and serum samples from other infections (n = 33). From the matrix-assisted laser desorption ionization-two-stage time of flight (MALDI-TOF/TOF) analysis, the proteins were identified as heavy subunits of E. histolytica lectin and E. histolytica pyruvate phosphate dikinase, respectively. Use of the E. histolytica lectin for diagnosis of ALA has been well reported by researchers and is being used in commercialized kits. However, this is the first report on the potential use of pyruvate phosphate dikinase for diagnosis of ALA; thus, this molecule merits further evaluation on its diagnostic value using a larger panel of serum samples.
    Matched MeSH terms: Antibodies, Protozoan/blood*; Biomarkers/blood
  7. Alimon AR, Ivan M, Jalaludin S
    Br J Nutr, 2011 Oct;106(8):1224-30.
    PMID: 21492494 DOI: 10.1017/S0007114511001462
    A 6-month experiment with nine dietary treatments was conducted to determine amounts of S plus Mo supplements required to maintain normal hepatic concentrations of Cu and Mo and to prevent chronic Cu toxicity in lambs fed palm kernel cake (PKC) diets. All diets consisted of PKC supplemented with minerals and vitamins, and with appropriate amounts per kg DM of S (level 0 or level 1 = 1 g) as sodium sulfate and/or Mo (level 0; level 1 = 4 mg; level 2 = 8 mg; level 3 = 16 mg; level 4 = 32 mg) as ammonium molybdate to form treatments S0Mo1, S0Mo2, S0Mo3, S0Mo4, S1Mo0, S1Mo1, S1Mo2, S1Mo3 and S1Mo4.There was no effect (P>0·05) of dietary treatments on the growth performance of the lambs. The dietary supplement of 1 g S plus 8 mg Mo per kg dietary DM (treatment S1Mo2) prevented accumulation of Cu in the liver without elevation of the concentration of Mo (P>0·05). The treatments S0Mo1, S0Mo2 and S0Mo3 increased (P 
    Matched MeSH terms: Copper/blood; Sheep, Domestic/blood
  8. Usin MF, Ramesh P, Lopez CG
    Malays J Pathol, 2004 Jun;26(1):43-8.
    PMID: 16190106
    Event reporting can provide data to study the failure points of an organization's work process. As part of the ongoing efforts to improve transfusion safety, a Medical Event Reporting System Transfusion Medicine, (MERS - TM) as designed by Kaplan et al was implemented in the Transfusion Medicine Unit of the University Malaya Medical Centre to provide a standardized means of organized data collection and analysis of transfusion errors, adverse events and near misses. An event reporting form was designed to detect, identify, classify and study the frequency and pattern of events occurring in the unit. Events detected were classified according to Eihdhoven Classification model (ECM) adopted for MERS - TM. Since our system reported all events, we called it Event Reporting System - Transfusion Medicine (ERS-TM). Data was collected and analyzed from the reporting forms for a period of five months from January 15th to June 15th 2002. The initial half of the period was a process of evaluation during which 118 events were reported, coded, analyzed and corrective measures adopted to prevent the recurrence of the same event. The latter half saw the reporting of 122 events following the adoption of corrective measures. There was a reduction in the occurrence of some events and an increase in others, which were mainly beyond the organization's control. A longer period of evaluation is necessary to identify the underlying contributory causes that can be useful to develop plans for corrective and preventive action and thereby reduce the rate of recurrence of errors through proper training and adoption of just culture.
    Matched MeSH terms: Blood Transfusion/adverse effects; Blood Transfusion/standards*
  9. Yvonne-Tee GB, Rasool AH, Halim AS, Rahman AR
    J Pharmacol Toxicol Methods, 2005 Sep-Oct;52(2):286-92.
    PMID: 16125628
    Postocclusive reactive hyperemia in forearm skin is a commonly used model for studying microvascular reactivity function, particularly in the assessment of vascular effect of topically applied pharmacological substances. In this study, we investigated the reproducibility of several different laser-Doppler-derived parameters in the measurement of postocclusive reactive hyperemia at forearm skin in healthy subjects.
    Matched MeSH terms: Forearm/blood supply; Skin/blood supply
  10. Saat M, Tochihara Y, Hashiguchi N, Sirisinghe RG, Fujita M, Chou CM
    J Physiol Anthropol Appl Human Sci, 2005 Jul;24(4):267-75.
    PMID: 16079566
    The effect of low-intensity exercise in the heat on thermoregulation and certain biochemical changes in temperate and tropical subjects under poorly and well-hydrated states was examined. Two VO2max matched groups of subjects consisting of 8 Japanese (JS) and 8 Malaysians (MS) participated in this study under two conditions: poorly-hydrated (no water was given) and well-hydrated (3 mL x Kg(-1) body weight of water was provided at onset of exercise, and the 15th, 35th and 55th min of exercise). The experimental room in both countries was adjusted to a constant level (Ta: 31.6+/-0.03 degrees C, rh: 72.3+/-0.13%). Subjects spent an initial 10 min rest, 60 min of cycling at 40% VO2max and then 40 min recovery in the experimental room. Rectal temperatures (Tre) skin temperatures (Tsk), heart rate (HR), heat-activated sweat glands density (HASG), local sweat rate (M sw-back) and percent dehydration were recorded during the test. Blood samples were analysed for plasma glucose and lactate levels.The extent of dehydration was significantly higher in the combined groups of JS (1.43+/-0.08%) compared to MS (1.15+/-0.05%). During exercise M sw-back was significantly higher in JS compared to MS in the well-hydrated condition. The HASG was significantly more in JS compared to MS at rest and recovery. Tre was higher in MS during the test. Tsk was significantly higher starting at the 5th min of exercise until the end of the recovery period in MS compared to JS. In conclusion, tropical natives have lower M sw-back associated with higher Tsk and Tre during the rest, exercise and recovery periods. However, temperate natives have higher M sw-back and lower Tsk and Tre during experiments in a hot environment. This phenomenon occurs in both poorly-hydrated and well-hydrated states with low intensity exercise. The differences in M sw-back, Tsk and Tre are probably due to a setting of the core temperature at a higher level and enhancement of dry heat loss, which occurred during passive heat exposure.
    Matched MeSH terms: Blood Glucose; Lactic Acid/blood
  11. Kotresha D, Noordin R
    APMIS, 2010 Aug;118(8):529-42.
    PMID: 20666734 DOI: 10.1111/j.1600-0463.2010.02629.x
    Toxoplasma gondii is an important human pathogen with a worldwide distribution. It is primarily of medical importance for pregnant women and immunocompromised patients. Primary infection of the former is often associated with fetal infection, which can lead to abortion or severe neonatal malformation. Immunocompromised patients are at risk of contracting the severe form of the disease that may be fatal. Thus, detection of T. gondii infection with high sensitivity and specificity is crucial in the management of the disease. Toxoplasmosis is generally diagnosed by demonstrating specific immunoglobulin M (IgM) and IgG antibodies to toxoplasma antigens in the patient's serum sample. Most of the commercially available tests use T. gondii native antigens and display wide variations in test accuracy. Recombinant antigens have great potential as diagnostic reagents for use in assays to detect toxoplasmosis. Thus in this review, we address recent advances in the use of Toxoplasma recombinant proteins for serodiagnosis of toxoplasmosis.
    Matched MeSH terms: Antibodies, Protozoan/blood*; Immunoglobulin G/blood
  12. Parthasarathy S, Ramanathan S, Ismail S, Adenan MI, Mansor SM, Murugaiyah V
    Anal Bioanal Chem, 2010 Jul;397(5):2023-30.
    PMID: 20454783 DOI: 10.1007/s00216-010-3707-7
    A new solid phase extraction method for rapid high performance liquid chromatography-UV determination of mitragynine in plasma has been developed. Optimal separation was achieved with an isocratic mobile phase consisting of acetonitrile-ammonium acetate buffer, 50 mM at pH 5.0 (50:50, v/v). The method had limits of detection and quantification of 0.025 and 0.050 microg/mL, respectively. The method was accurate and precise for the quantitative analysis of mitragynine in human and rat plasma with within-day and between-day accuracies between 84.0 and 109.6%, and their precision values were between 1.7 and 16.8%. Additional advantages over known methods are related to the solid phase extraction technique for sample preparation which yields a clean chromatogram, a short total analysis time, requires a smaller amount of plasma samples and has good assay sensitivity for bioanalytical application. The method was successfully applied in pharmacokinetic and stability studies of mitragynine. In the present study, mitragynine was found to be fairly stable during storage and sample preparation. The present study showed for the first time the detailed pharmacokinetic profiles of mitragynine. Following intravenous administration, mitragynine demonstrated a biphasic elimination from plasma. Oral absorption of the drug was slow, prolonged and was incomplete, with a calculated absolute oral bioavailability value of 3.03%. The variations observed in previous pharmacokinetic studies after oral administration of mitragynine could be attributed to its poor bioavailability rather than to the differences in assay method, metabolic saturation or mitragynine dose.
    Matched MeSH terms: Plant Extracts/blood*; Secologanin Tryptamine Alkaloids/blood*
  13. Chan SP, Ji LN, Nitiyanant W, Baik SH, Sheu WH
    Diabetes Res Clin Pract, 2010 Aug;89(2):e30-2.
    PMID: 20541826 DOI: 10.1016/j.diabres.2010.05.008
    Symptoms of hypoglycemia were reported by 35.8% of patients with type 2 diabetes treated with oral antihyperglycemic agents in the Asia-Pacific region. Symptoms were severe in 11.6% and very severe in 8.2% of patients experiencing hypoglycemia.
    Matched MeSH terms: Diabetes Mellitus, Type 2/blood*; Hypoglycemia/blood*
  14. Venkatesh G, Majid MI, Ramanathan S, Mansor SM, Nair NK, Croft SL, et al.
    Biomed Chromatogr, 2008 May;22(5):535-41.
    PMID: 18205140 DOI: 10.1002/bmc.965
    A simple, sensitive and specific reversed-phase high-performance liquid chromatographic method with UV detection at 251 nm was developed for quantitation of buparvaquone (BPQ) in human and rabbit plasma. The method utilizes 250 microL of plasma and sample preparation involves protein precipitation followed by solid-phase extraction. The method was validated on a C18 column with mobile phase consisting of ammonium acetate buffer (0.02 m, pH 3.0) and acetonitrile in the ratio of 18:82 (v/v) at a flow rate of 1.1 mL/min. The calibration curves were linear (correlation coefficient>or=0.998) in the selected range. The method is specific and sensitive with limit of quantitation of 50 ng/mL for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and BPQ was found to be stable. Partial validation studies were carried out using rabbit plasma and intra- and inter-day precision and accuracy were within 7%. This method is simple, reliable and can be routinely used for preclinical pharmacokinetic studies for BPQ.
    Matched MeSH terms: Antiprotozoal Agents/blood; Naphthoquinones/blood*
  15. Rahman S, Ismail AA, Ismail SB, Naing NN, Rahman AR
    Diabetes Res Clin Pract, 2008 May;80(2):253-8.
    PMID: 18249457 DOI: 10.1016/j.diabres.2007.12.010
    Type II diabetes patients have increased risk of macrovascular complications compared with the general population. Arterial stiffness is considered as an independent predictor of macrovascular events. This study investigated arterial stiffness in newly diagnosed never treated diabetes and impaired glucose tolerance (IGT) patients without any traditional cardiovascular diseases (CVD) risk factors. After preliminary screening of 1620 individuals, 30 diabetic and 30 IGT patients were recruited and compared with age- and sex-matched 30 normoglycaemic subjects. The subjects were newly diagnosed, never treated, normotensive, non-obese, non-hyperlipidaemic and non-smoker. Haemodynamic variables, pulse wave velocity (PWV) and augmentation index (AI) were measured. The PWV was significantly higher in diabetic patients (10.37+/-2.64m/s vs. 8.70+/-1.29m/s; p=0.035) and was of borderline significant in IGT subjects (9.54+/-1.56m/s vs.8.70+/-1.29m/s, p=0.078) compared to normoglycaemic individuals. Augmentation index was higher of borderline significant in diabetic (134.53+/-17.32% vs. 129.17+/-11.18%, p=0.055) and IGT patients (132.02+/-16.11% vs. 129.17+/-11.18%, p=0.059) compared to normoglycaemic individuals. The study demonstrated that newly diagnosed never treated diabetic patients without any CV complications had early manifestation of macrovascular diseases as evident by increased arterial stiffness. The findings also revealed early manifestations of preclinical vasculopathy and potentially increased risk for development of macrovascular diseases at an early age in diabetic patients.
    Matched MeSH terms: Blood Pressure; Lipids/blood
  16. Tarmalinggam Y, Prakash ES
    Adv Physiol Educ, 2007 Dec;31(4):370-1.
    PMID: 18057413
    Matched MeSH terms: Bilirubin/blood; Jaundice, Chronic Idiopathic/blood*
  17. Yankuzo HM, Emilia ST, Shaari R, Yaacob NS
    Asian Pac J Cancer Prev, 2014;15(16):6721-6.
    PMID: 25169515
    BACKGROUND: The aim of this preliminary study was to address variations of responses observed with different starting tumor sizes of 10 and 15 mm, and the effects of different doses of tamoxifen (TAM) on experimental rat mammary tumors.

    MATERIALS AND METHODS: Thirty-five inbred female Sprague Dawley rats aged 43 days were administered with three weekly doses of N-methyl-N-nitrosourea (NMU) intraperitoneally (ip) at 50 mg/kg body weight. Animals were randomized (beginning from 10 mm tumor size) into four TAM-treated (50, 100, 200 and 500 μg/day) groups of six animals each, and another group (n=6) treated with TAM 100 μg/day at starting tumour size of 15 mm. The animals were treated by oral gavage daily for 8 weeks before sacrifice.

    RESULTS: Serum urea and creatinine, and overall physical tumor burden were significantly modulated in animals treated with variable doses of TAM compared to the untreated controls (n=5). Final body weight and tumor number were significantly different in the 10 mm-treated animals compared to those treated at 15 mm. There were no significant differences in histopathological features among all the groups.

    CONCLUSIONS: Our findings suggest the importance of standardizing tumour size and drug doses before initiation of treatment, particularly in the direct comparison of basic end-tumour physical parameters.

    Matched MeSH terms: Creatinine/blood; Urea/blood
  18. Wilailak S, Chan KK, Chen CA, Nam JH, Ochiai K, Aw TC, et al.
    J Gynecol Oncol, 2015 Jan;26(1):46-53.
    PMID: 25310857 DOI: 10.3802/jgo.2015.26.1.46
    The purpose of this study was to develop a risk prediction score for distinguishing benign ovarian mass from malignant tumors using CA-125, human epididymis protein 4 (HE4), ultrasound findings, and menopausal status. The risk prediction score was compared to the risk of malignancy index and risk of ovarian malignancy algorithm (ROMA).
    Matched MeSH terms: Biomarkers, Tumor/blood*; CA-125 Antigen/blood
  19. Phan K, Kim KW, Hashim JH
    Environ Res, 2014 Nov;135:37-41.
    PMID: 25262072 DOI: 10.1016/j.envres.2014.07.031
    We investigated relationship of arsenicosis symptoms with total blood arsenic (BAs) and serum albumin (SAlb) of residents in the Mekong River basin of Cambodia. We found that arsenicosis patients had significantly higher BAs and lower SAlb than asymptomatic villagers (Mann-Whitney U test, p<0.01). Arsenicosis symptoms were found to be 76.4% (1.764 times) more likely to develop among individuals having an SAlb≤44.3gL(-1) than among those who had an SAlb>44.3gL(-1) (OR=1.764, 95% CI=0.999-3.114) and 117.6% (2.176 times) as likely to occur among those with BAs>5.73µgL(-1) than for those having BAs≤5.73µgL(-1) (OR=2.176, 95% CI=1.223-3.872). Furthermore, a significant negative correlation was also found between BAs and SAlb (rs (199)=-0.354, p<0.0001). As such, this study suggests that people with low SAlb and/or high BAs are likely to rapidly develop arsenicosis symptoms.
    Matched MeSH terms: Water Pollutants, Chemical/blood; Arsenic Poisoning/blood*
  20. Periayah MH, Halim AS, Yaacob NS, Saad AZ, Hussein AR, Rashid AH, et al.
    Biomed Res Int, 2014;2014:653149.
    PMID: 25247182 DOI: 10.1155/2014/653149
    Platelet membrane receptor glycoprotein IIb/IIIa (gpiibiiia) is a receptor detected on platelets. Adenosine diphosphate (ADP) activates gpiibiiia and P2Y12, causing platelet aggregation and thrombus stabilization during blood loss. Chitosan biomaterials were found to promote surface induced hemostasis and were capable of activating blood coagulation cascades by enhancing platelet aggregation. Our current findings show that the activation of the gpiibiiia complex and the major ADP receptor P2Y12 is required for platelet aggregation to reach hemostasis following the adherence of various concentrations of chitosan biomaterials [7% N,O-carboxymethylchitosan (NO-CMC) with 0.45 mL collagen, 8% NO-CMC, oligochitosan (O-C), and oligochitosan 53 (O-C 53)]. We studied gpiibiiia and P2Y12 through flow cytometric analysis and western blotting techniques. The highest expression of gpiibiiia was observed with Lyostypt (74.3 ± 7.82%), followed by O-C (65.5 ± 7.17%). Lyostypt and O-C resulted in gpiibiiia expression increases of 29.2% and 13.9%, respectively, compared with blood alone. Western blot analysis revealed that only O-C 53 upregulated the expression of P2Y12 (1.12 ± 0.03-fold) compared with blood alone. Our findings suggest that the regulation of gpiibiiia and P2Y12 levels could be clinically useful to activate platelets to reach hemostasis. Further, we show that the novel oligochitosan is able to induce the increased expression of gpiibiiia and P2Y12, thus accelerating platelet aggregation in vitro.
    Matched MeSH terms: Blood Platelets/drug effects; Blood Platelets/physiology*
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