Detrimental effects of fresh frozen plasma transfusions on postoperative outcomes in patients undergoing liver resection for hepatocellular carcinoma.

BACKGROUND: Perioperative fresh frozen plasma (FFP) is commonly transfused to patients undergoing liver resection for hepatocellular carcinoma (HCC), but its impacts in this population remain unknown. This study aimed to investigate the association of perioperative FFP transfusion with short-term and long-term outcomes in these patients. METHODS: We retrospectively identified and retrieved clinical data for HCC patients undergoing liver resection between March, 2007 and December, 2016. Study outcomes included postoperative bacterial infection, extended length of stay (LOS) and survival. Propensity score (PS) matching was used to determine the association of FFP transfusion with each outcome. RESULTS: A total of 1427 patients were included, and 245 of them received perioperative FFP transfusions (17.2%). Patients received perioperative FFP transfusions were older, underwent liver resection in the earlier time period, and had more extensive resection, poorer clinical conditions, and higher proportions of receiving other blood components. Perioperative FFP transfusion was associated with higher odds of both postoperative bacterial infection (OR = 1.77, p = 0.020) and extended LOS (OR = 1.93, p=<0.001), and the results remained similar after PS-matching. However, perioperative FFP transfusion did not significantly affect survival in these patients (HR = 1.17, p = 0.185). A potential association of postoperative FFP transfusions and poorer 5-year but not overall survival was observed in a subgroup of patients with low postoperative albumin levels after PS-matching. CONCLUSION: Perioperative FFP transfusions were associated with poorer short-term postoperative outcomes in HCC patients undergoing liver resection, including postoperative bacterial infection and extended LOS. Reducing perioperative FFP transfusions has the potential to improve their postoperative outcomes.

A validation and modification of PLASMIC score by adjusting the criteria of mean corpuscular volume and international normalized ratio.

BACKGROUND: The PLASMIC score was developed for distinguishing thrombotic thrombocytopenic purpura (TTP) from other types of thrombotic microangiopathy. However, two components of the PLASMIC score, mean corpuscular volume (MCV) and international normalized ratio (INR), showed non-significant differences between TTP and non-TTP patients in previous validations. Here, we validate the PLASMIC score and aim to modify it by adjusting the criteria of MCV and INR. MATERIALS AND METHODS: A retrospective validation of suspected TTP patients was performed by reviewing electronic medical records from two medical centers in Taiwan. The performance of different modified types of the PLASMIC score was carried out. RESULTS: Among 50 patients included in the final analysis, 12 were diagnosed with TTP based on deficiency of ADAMTS13 activity and clinical judgement. When stratified by high (score ≥ 6) and low-intermediate risk (score < 6), the positive predictive value (PPV) of the PLASMIC score to predict TTP was 0.45 (95% confidence interval [CI]: 0.29-0.61). The area under curve (AUC) was 0.70 (95% CI: 0.56-0.82). When adjusting the criteria of the PLASMIC score from MCV < 90 fL to MCV ≥ 90 fL, the PPV increased to 0.57 (95% CI: 0.37-0.75). The AUC was 0.75 (95% CI: 0.61-0.87). When adjusting the INR from >1.5 to >1.1, the PPV increased to 0.56 (95% CI: 0.39-0.71). The AUC was 0.81 (95% CI: 0.68-0.90). CONCLUSION: MCV ≥ 90 fL and/or INR > 1.1 might be suitable modifications for PLASMIC score but should be validated in a larger sample size.

Metabolomic Analysis of Platelets of Patients With Aspirin Non-Response.

Background: Aspirin is the most commonly used antiplatelet agent for the prevention of cardiovascular diseases. However, a certain proportion of patients do not respond to aspirin therapy. The mechanisms of aspirin non-response remain unknown. The unique metabolomes in platelets of patients with coronary artery disease (CAD) with aspirin non-response may be one of the causes of aspirin resistance. Materials and Methods: We enrolled 29 patients with CAD who were aspirin non-responders, defined as a study subject who were taking aspirin with a platelet aggregation time less than 193 s by PFA-100, and 31 age- and sex-matched patients with CAD who were responders. All subjects had been taking 100 mg of aspirin per day for more than 1 month. Hydrophilic metabolites from the platelet samples were extracted and analyzed by nuclear magnetic resonance (NMR). Both 1D 1H and 2D J-resolved NMR spectra were obtained followed by spectral processing and multivariate statistical analysis, such as partial least squares discriminant analysis (PLS-DA). Results: Eleven metabolites were identified. The PLS-DA model could not distinguish aspirin non-responders from responders. Those with low serum glycine level had significantly shorter platelet aggregation time (mean, 175.0 s) compared with those with high serum glycine level (259.5 s). However, this association became non-significant after correction for multiple tests. Conclusions: The hydrophilic metabolic profile of platelets was not different between aspirin non-responders and responders. An association between lower glycine levels and higher platelet activity in patients younger than 65 years suggests an important role of glycine in the pathophysiology of aspirin non-response.

Thromboelastography characterized CD36 null subjects as slow clot formation and indicative of hypocoagulability.

BACKGROUND: Platelet CD36 is the receptor for oxidized low-density lipoprotein and collagen. The conventional platelet test cannot distinguish CD36-null subjects from normal expression subjects. Thromboelastography (TEG) testing can analyze global hemostasis. TEG testing data on CD36-null subjects are not available. METHODS: Our subjects were 40 apheresis platelet donors, including 8 CD36-null individuals. We grouped the donors according to the platelet CD36 expression levels to assess the effects of platelet CD36 expression levels on TEG measurement variables. RESULTS: The whole blood TEG test revealed that CD36-null subjects had prolonged reaction time of fibrin formation (TEG R time) and a slower rate to build up cross-linked fibrin (TEG α angle). The final maximal amplitudes of clot formation showed little difference between CD36-null individuals and normal expression individuals. Correlation analysis showed that CD36 expression levels were negatively correlated with TEG R time (r = -0.342, p = 0.031) and positively correlated with the TEG α angle (0.379, p = 0.016). TEG testing on apheresis platelet samples with diminished heterocellular interaction did not reveal differences between CD36-null and normal expression individuals. A subanalysis of the data of a group of healthy subjects showed that platelet CD36 levels correlated positively with platelet-monocyte aggregates (PMAs). Low PMA can diminish heterocellular interaction and likely explain the abnormal TEG results observed in CD36-null individuals. CONCLUSION: TEG distinguishes CD36-null subjects from normal CD36 expression subjects as having a slower rate of fibrin formation and reassessment of TEG-based diagnostic monitoring is necessary for CD36 null subjects.

Establishment of calculated panel reactive antibody and its potential benefits in improving the kidney allocation strategy in Taiwan.

BACKGROUND/PURPOSE: Renal transplant candidates who are highly sensitized to human leukocyte antigens (HLAs) tend to wait longer to find a matched donor and have poor outcomes. Most organ-sharing programs prioritize highly sensitized patients in the allocation scoring system. The HLA sensitization status is traditionally evaluated by the panel-reactive antibody (PRA) assay. However, this assay is method dependent and does not consider the ethnic differences in HLA frequencies. A calculated PRA (cPRA), based on a population's HLA frequency and patients' unacceptable antigens (UAs), correctly estimates the percentage of donors suitable for candidates. The Taiwan Organ Registry and Sharing Center does not prioritize sensitized patients. We propose that the incorporation of the cPRA and UAs into the renal allocation program will improve the local kidney allocation policy. METHODS: We established a cPRA calculator using 6146 Taiwanese HLA-A, -B, -C, -DR, and -DQ phenotypes. We performed simulated allocation based on the concept of acceptable mismatch for 76 candidates with cPRA values exceeding 80%. RESULTS: We analyzed 138 waitlisted renal transplant candidates at our hospital, and we determined that the concordance rate of the cPRA and PRA for highly sensitized (%PRA > 80%) candidates was 92.5%, which decreased to 20% for those with %PRA < 80%. We matched 76 highly sensitized patients based on acceptable mismatch with the HLA phenotypes of 93 cadaver donors. Forty-six patients (61%) found at least one suitable donor. CONCLUSION: The application of the cPRA and acceptable mismatch can benefit highly sensitized patients and reduce positive lymphocyte cytotoxicity crossmatch.

Interference of daratumumab with pretransfusion testing, mimicking a high-titer, low avidity like antibody.

Daratumumab is a monoclonal immunoglobulin against CD38 and has been approved for treating patients with refractory multiple myeloma. The presence of daratumumab in the sera can interfere with pretransfusion testing due to the weakly expression of CD38 on red cells. The reactivity could be mistaken as autoantibody (if autocontrol is positive) or alloantibody (if autocontrol is negative). We present a case that demonstrates daratumumab could mimic a high titer low avidity (HTLA) alloantibody. A 34-year-old male patient of refractory myeloma was recruited in phase three clinical trial involving daratumumab. Samples were sent to the blood bank for pretransfusion testing. Without knowledge of patient having used daratumumab, we mistook the reactivity in the patient's sera as an HTLA antibody due to the results of negative autocontrol and high titers of antibody activity. Antibody screen showed a panreactive pattern and the reactivity against screening cells was up to a titer of 1: 1240. The reactivity was weaker against cord cells than adult cells, became weaker against ZZAP-treated cells and became negative against DDT-treated cells. A discussion with attending physician finally revealed the reactivity was due to the interference caused by daratumumab. The case demonstrates good communication is essential in performing pretransfusion testing for patients receiving daratumumab and other new biological regimens that can interfere with compatibility test.

Intermediate CD14++CD16+ monocyte predicts severe coronary stenosis and extensive plaque involvement in asymptomatic individuals.

Circulating leukocyte subtypes and monocyte subsets are independent predictors of cardiovascular events. We hypothesized that an increased leukocyte subtype would predict severe coronary stenosis and extensive plaque involvement. We retrospectively analyzed clinical, laboratory, and coronary CT data in a total of 588 asymptomatic adults (69% men; mean age, 57 ± 9 years) undergoing a general health check-up. Intermediate CD14++CD16+ monocyte count had the strongest association with mixed and calcified plaque scores, whereas the numbers of neutrophils and classical CD14++CD16- monocytes were significantly associated with non-calcified plaque score. Only high CD14++CD16+ monocyte count (>12 cells/µL) significantly predicted extensive plaque involvement [odds ratio 3.16 (95% confidence interval 1.84-5.43), P < 0.001; quartile 4 vs. 1-3] and severe coronary stenosis [3.67 (1.84-7.33), P < 0.001; quartile 4 vs. 1-3] after adjustments for Framingham Risk Score (FRS), metabolic syndrome, and C-reactive protein. The CD14++CD16+ monocyte count, when added to FRS, significantly reclassified 30.4 and 26.7% of the overall and 50.2 and 36.2% of the intermediate-risk population (FRS 6-20%) for predicting extensive plaque involvement and severe coronary stenosis, respectively. Thus, in asymptomatic individuals, intermediate CD14++CD16+ monocyte could independently predict severe CAD and improve risk stratification.

The association of carotid intima-media thickness with serum Level of perfluorinated chemicals and endothelium-platelet microparticles in adolescents and young adults.

Perfluorinated chemicals (PFCs) have been widely used in a variety of products worldwide. Our previous study has documented a close association of higher serum level of perfluorooctane sulfonate (PFOS) with an increased carotid intima-media thickness (CIMT) in a cohort of adolescents and young adults. Herein, we further investigated the association of oxidative stress, circulating endothelial microparticles (EMPs) and platelet microparticles (PMPs) with PFCs and CIMT in humans. We recruited 848 subjects (12-30years old) from a population-based sample to determine the relationship between serum levels of PFCs, EMPs (CD62E and CD31+/CD42a-), PMPs (CD62P and CD31+/CD42a+), and the urine levels of 8-hydroxydeoxyguanosine (8-OHdG) and CIMT. The results showed that CD31+/CD42a- (endothelial apoptosis marker) and CD31+/CD42a+ (platelet apoptosis marker) increased significantly across quartiles of PFOS in multiple linear regression analysis. Furthermore, the elevation of CD31+/CD42a- and CD31+/CD42a+ corresponded to the increase of the odds ratios of thicker CIMT (greater than 50th percentile) with higher serum PFOS concentration (greater than 50%) (OR=2.86, 95% C.I.=1.69-4.84, P<0.001) in logistic regression models. There was no association between PFC concentration and 8-OHdG. In conclusion, we found the positive association between PFOS and CIMT that was more evident when serum levels of EMPs (CD31+/CD42a-) and PMPs (CD31+/CD42a+) were elevated. Further studies are warranted to investigate the causal inference of PFOS exposure on endothelial cell damage and atherosclerosis.

The ratio of epicardial to body fat improves the prediction of coronary artery disease beyond calcium and Framingham risk scores.

The association between epicardial fat and coronary artery disease (CAD) might be affected by general adiposity. We aimed to determine whether the percentage of epicardial adipose tissue (%EAT), defined as the mass ratio of epicardial fat to body fat, could improve prediction of asymptomatic CAD. We consecutively enrolled 846 adults who underwent coronary computed tomography angiography as part of a health check-up and assessed their coronary stenosis severity and epicardial fat mass. Body fat mass was measured by bioelectrical impedance analysis. Subjects with CAD history, hyperthyroidism, pitting edema, or subjects taking diuretics or thiazolidinedione were excluded. Obstructive CAD was defined as at least one coronary artery with 50 % or greater obstruction, and severe CAD was defined as 70 % or greater obstruction. The %EAT had the maximum area under the curve for predicting the presence of CAD and superior discriminative performance to EAT and other EAT-indexed parameters. Multivariable logistic regression analysis revealed that %EAT >0.41 % was a predictor of obstructive CAD [odds ratio 3.59 (95 % confidence interval 2.28-5.64)], and %EAT >0.47 % was a predictor of severe CAD [4.01 (2.01-7.99)] after adjustment for calcium score and Framingham risk score. This prediction was more pronounced in subjects with higher body fat percentage (≥25 % for men and ≥35 % for women), Framingham risk score (≥10 %), or calcium score (≥100). A spillover of body fat at epicardium over a critical threshold is associated with significant coronary stenosis. This association was independent of obesity, coronary calcium burden, and Framingham risk factors.

Positive association between concentration of phthalate metabolites in urine and microparticles in adolescents and young adults.

Di-(2-ethylhexyl) phthalate (DEHP) has been used worldwide in various products for many years. In vitro studies have shown that exposure to DEHP and its metabolite mono(2-ethylhexyl) phthalate (MEHP) induces endothelial cell apoptosis. Moreover, exposure to DEHP had been linked to cardiovascular risk factors and cardiovascular diseases in epidemiological studies. Circulating microparticles have been known to be indicators of vascular injury. However, whether DEHP or its metabolites are independently associated with microparticles in humans remains unknown. From 2006 to 2008, we recruited 793 subjects (12-30years) from a population-based sample to participate in this cardiovascular disease prevention examination. Each participant was subjected to interviews and biological sample collection to determine the relationship between concentrations of DEHP metabolites MEHP, mono(ethyl-5-hydroxyhexyl) phthalate, and mono(2-ethly-5-oxoheyl) phthalate in urine and concentrations of endothelial microparticles (CD62E and CD31+/CD42a-), platelet microparticles (CD62P and CD31+/CD42a+), and CD14 in serum. Multiple linear regression analysis revealed that an ln-unit increase in MEHP concentration in urine was positively associated with an increase in serum microparticle counts/µL of 0.132 (±0.016) in CD31+/CD42a- (endothelial apoptosis marker), 0.117 (±0.023) in CD31+/CD42a+ (platelet apoptosis marker), and 0.026 (±0.007) in CD14 (monocyte, macrophage, and neutrophil activation marker). There was no association between DEHP metabolite concentration and CD62E or CD62P. In conclusion, a higher MEHP concentration in urine was associated with an increase in endothelial and platelet microparticles in this cohort of adolescents and young adults. Further studies are warranted to clarify the causal relationship between exposure to DEHP and atherosclerosis.

Severe lymphopenia is associated with elevated plasma interleukin-15 levels and increased mortality during severe sepsis.

Sepsis-related mortality has been found increased in RAG-1 knockout mice. However, in patients admitted to medical intensive care units, it is unknown whether severe lymphocyte depletion at admission is associated with increased interleukin (IL)-7 and IL-15 levels in circulation, and increased mortality. We prospectively enrolled 92 patients who were admitted to medical intensive care units for severe sepsis or septic shock. At admission, 24 patients (26.1%) had severe lymphopenia, defined as lymphocyte counts of less than 0.5 × 10(3)/µL. Severe lymphopenia was associated with significantly higher plasma levels of tumor necrosis factor α, IL-6, IL-8, and IL-10 and was also independently associated with 28-day mortality (adjusted hazard ratio, 3.532; 95% confidence interval, 1.482-8.416; P = 0.004). The levels of plasma IL-15, but not IL-7, were increased modestly in patients with severe lymphopenia compared with those without (median, 12.2 vs. 6.4 pg/mL; P = 0.005). The elevated plasma IL-15 levels were contrarily associated with significantly decreased B-cell lymphoma 2 mRNA expression in peripheral blood mononuclear cells. In conclusion, severe lymphopenia was associated with increased mortality in patients with severe sepsis. We found that patients with sepsis with severe lymphopenia had down-regulated B-cell lymphoma 2 mRNA expression in peripheral blood mononuclear cells, despite increased plasma IL-15 concentrations. Whether IL-7 and IL-15 are insufficient in patients with severe lymphopenia during severe sepsis warrants further investigations.

In acute kidney injury, indoxyl sulfate impairs human endothelial progenitor cells: modulation by statin.

Renal ischemia rapidly mobilizes endothelial progenitor cells (EPCs), which provides renoprotection in acute kidney injury (AKI). Indoxyl sulfate (IS) is a protein-binding uremic toxin with a potential role in endothelial injury. In this study, we examined the effects and mechanisms of action of IS on EPCs in AKI. Forty-one consecutive patients (26 male; age, 70.1 ± 14.1 years) diagnosed with AKI according to the AKIN criteria were enrolled. The AKI patients had higher serum IS levels than patients with normal kidney function (1.35 ± 0.94 × 10(-4)M vs. 0.02 ± 0.02 × 10(-4)M, P < 0.01). IS levels were negatively correlated to the number of double-labeled (CD34(+)KDR(+)) circulating EPCs (P < 0.001). After IS stimulation, the cells displayed decreased expression of phosphorylated endothelial nitric oxide (NO) synthase, vascular cell adhesion molecule-1, increased reactive oxygen species, decreased proliferative capacity, increased senescence and autophagy, as well as decreased migration and angiogenesis. These effects of IS on EPCs were reversed by atorvastatin. Further, exogenous administration of IS significantly reduced EPC number in Tie2-GFP transgenic mice and attenuated NO signaling in aortic and kidney arteriolar endothelium after kidney ischemia-reperfusion injury in mice, and these effects were restored by atorvastatin. Our results are the first to demonstrate that circulating IS is elevated in AKI and has direct effects on EPCs via NO-dependent mechanisms both in vitro and in vivo. Targeting the IS-mediated pathways by NO-releasing statins such as atorvastatin may preempt disordered vascular wall pathology, and represent a novel EPC-rescued approach to impaired neovascularization after AKI.

Endothelial progenitor cells in primary aldosteronism: a biomarker of severity for aldosterone vasculopathy and prognosis.

CONTEXT: Primary aldosteronism (PA) is associated with a higher incidence of cardiovascular events, probably through mineralocorticoid receptor (MR)-dependent endothelial cell dysfunction, in comparison with essential hypertension (EH). OBJECTIVE: Our objective was to investigate the number and function of endothelial progenitor cells (EPC) in PA and the relationship with arterial stiffness and disease progression. DESIGN AND SETTING: We conducted a prospective study of the change of EPC number and outcome of PA patients after treatment at a tertiary medical center. PRIMARY OUTCOMES: Changes in arterial stiffness and EPC number after treatment and the curability of hypertension were assessed. PATIENTS: A total of 113 PA patients (87 patients diagnosed with aldosterone-producing adenoma, 26 with idiopathic hyperaldosteronism) and 55 patients with EH participated. RESULTS: PA patients had higher arterial stiffness than EH patients (P = 0.006), with a lower numbers of circulating EPC and endothelial colony-forming units (P < 0.05). The differences were ameliorated at 6 months after unilateral adrenalectomy or treatment with spironolactone. Expression of MR was identified in the EPC. The number of circulating EPC was inversely correlated with the plasma aldosterone concentration (P = 0.021), arterial stiffness (P = 0.029) and serum high-sensitivity C-reactive protein (P = 0.03). High-dose aldosterone (10(-5) and 10(-6) m) attenuated EPC proliferation and angiogenesis in vitro. Among the 45 patients who underwent unilateral adrenalectomy, 32 (71%) were cured of hypertension. The preoperative number of EPC [log(EPC number percent) >-3.6] predicted the curability of hypertension after adrenalectomy (P = 0.003). CONCLUSIONS: The relative deficiency of EPC in PA patients may contribute to aldosterone vasculopathy, which can be reversed by adrenalectomy and spironolactone. High aldosterone levels attenuated EPC proliferation and angiogenesis. Circulating EPC number may be a valuable biomarker to identify PA patients with a high incidence of arterial stiffness and to predict postoperative residual hypertension of aldosterone-producing adenoma.

Comparison of corneal epitheliotrophic capacity among different human blood-derived preparations.

PURPOSE: To compare the corneal epitheliotrophic capacity of different human blood-derived preparations, including cord blood serum (CBS), peripheral blood serum (PBS), and fresh frozen plasma (FFP) on bovine corneal epithelial cells. MATERIALS AND METHODS: The concentrations of epithelial growth factor, transforming growth factor ß1, insulin-like growth factor 1, hyaluronic acid, fibronectin, albumin, glucose, and calcium in different human blood derivatives were evaluated using enzyme-linked immunosorbent assay or biochemical methods. Cultivated bovine corneal epithelial cells were incubated with various blood derivatives, and cell proliferation, migration, and differentiation were evaluated by colorimetric assay, Boyden chamber chemotaxis assay, wounding assay, scanning electron microscopy, and transepithelial electric resistance measurements. Wound closure was assessed using a scratch-induced directional wounding assay. RESULTS: Of the 3 human blood derivatives evaluated, CBS had the highest concentrations of epithelial growth factor, transforming growth factor ß1, and hyaluronic acid (P < 0.05). FFP had the lowest concentration of calcium and the highest concentration of glucose (P < 0.05). CBS demonstrated the highest ability to promote cellular proliferation, followed by PBS and FFP (P < 0.05). CBS was also the best in promoting cellular differentiation because scanning electron microscopy demonstrated coherent monolayers of flattened and polygonal-shaped cells with evenly distributed microvilli. Transepithelial electric resistance was noted to be the highest for cells incubated in CBS, indicating formation of well-differentiated cells with functional tight junction (P < 0.05). Cells cultivated with FFP were the least capable of promoting proliferation, migration, and differentiation. CONCLUSIONS: Different human blood derivatives may have different concentrations of epitheliotrophic factors. CBS is generally superior to PBS in promoting corneal epithelial proliferation and differentiation.

Epitope-based matching for HLA-alloimmunized platelet refractoriness in patients with hematologic diseases.

BACKGROUND: For HLA-alloimmunized patients, platelet (PLT) concentrations are provided either at matched HLA-A and HLA-B loci or by serologic cross-reactivity groups (CREG) matching strategy. However, this method has some limitations. STUDY DESIGN AND METHODS: In this study, the epitope-based matching (EBM) method was evaluated for selecting proper HLA-typed PLTs for patients with PLT transfusion refractoriness. Bead-based single-antigen HLA antibody detection method and HLAMatchmaker software were used to define the epitopes recognized by HLA-specific antibodies and to select compatible PLTs for nine patients with alloimmunized refractoriness. Corrected count increments (CCIs) were prospectively determined to compare successful transfusion rates among different matching methods in 142 PLT transfusions. In addition, HLA antibodies were serially detected to see whether any emerging antibodies appeared after receiving the EBM-matched PLTs. RESULTS: The transfusion success rates evaluated with 1-hour CCIs for perfect matching or lacking any mismatching at HLA-A and -B locus (A/BU)-matched, CREG-matched, and EBM-matched PLTs were 85.2, 63.2, and 83.7%, respectively. Compared to CREG-matched PLTs, EBM-matched PLTs showed better transfusion results (p = 0.035). In the follow-up study (7 months; range, 3-13 months), no emerging HLA-specific antibodies were detected after receiving EBM-matched PLTs. CONCLUSIONS: EBM performed on the basis of bead-based single-antigen HLA antibody detection coupled with the HLAMatchmaker program is recommended in choosing proper PLTs for refractory patients when A/BU-matched PLTs were not available.

NP-184[2-(5-methyl-2-furyl) benzimidazole], a novel orally active antithrombotic agent with dual antiplatelet and anticoagulant activities.

The established antiplatelet and anticoagulant agents show beneficial effects in the treatment of thromboembolic diseases; however, these drugs still have considerable limitations. The effects of NP-184, a synthetic compound, on platelet functions, plasma coagulant activity, and mesenteric venule thrombosis in mice were investigated. NP-184 concentration-dependently inhibited the human platelet aggregation induced by collagen, arachidonic acid (AA), and U46619, a thromboxane (TX)A(2) mimic, with IC(50) values of 4.5 +/- 0.2, 3.9 +/- 0.1, and 9.3 +/- 0.5 microM, respectively. Moreover, NP-184 concentration-dependently suppressed TXA(2) formations caused by collagen and AA. In exploring effects of NP-184 on enzymes involved in TXA(2) synthesis, we found that NP-184 selectively inhibited TXA(2) synthase activity with an IC(50) value of 4.3 +/- 0.2 microM. Furthermore, NP-184 produced a right shift of the concentration-response curve of U46619, indicating a competitive antagonism on TXA(2)/prostaglandin H(2) receptor. Intriguingly, NP-184 also caused a concentration-dependent prolongation of the activated partial thromboplastin time (aPTT) with no changes in the prothrombin and thrombin time, indicating that it selectively impairs the intrinsic coagulation pathway. Oral administration of NP-184 significantly inhibited thrombus formation of the irradiated mesenteric venules in fluorescein sodium-treated mice without affecting the bleeding time induced by tail transection. However, after oral administration, NP-184 inhibited the ex vivo mouse platelet aggregation triggered by collagen and U46619 and also prolonged aPTT. Taken together, the dual antiplatelet and anticoagulant activities of NP-184 may have therapeutic potential as an oral antithrombotic agent in the treatment of thromboembolic disorders.

The relationship of p1 and lewis antigens with peritoneal dialysis-related Escherichia coli peritonitis.

It has been known that the P1 and Lewis antigens on red blood cells (RBCs) affect the risk of Escherichia coli-related urinary tract infection. In the present study, we investigated the associations between those antigens and peritoneal dialysis (PD)-related peritonitis and E. coli peritonitis. We recruited 155 patients (66 men, 89 women) who were under PD treatment in July 2005, checked the P1 and Lewis antigen status of their RBCs, reviewed their medical charts, and recorded the dates and the causative pathogens of peritonitis episodes. The relationships between peritonitis and the antigens were analyzed. The mean age of these PD patients was 52.5 +/- 14.9 years, and the mean PD duration was 39.8 +/- 38.2 months. A total of 66 peritonitis episodes occurred (over 93.4 patient-months) in 41 patients, with 8 patients having more than 1 episode. In particular, E. coli peritonitis accounted for 16 of the 66 peritonitis episodes. We fitted two multiple Cox proportional hazards models (with the robust variance method) for predicting the hazard rates of peritonitis-free and E. coli peritonitis-free survival times to our right-censored data with recurrent events. We found that patients on PD treatment for less than 4 years with (A) lower serum albumin, (B) one or more previous peritonitis episodes, or (C) negative Lewis a and positive Lewis b antigens (secretor) would be at higher risk of peritonitis. And, conditioning on blood type, the PD patients with one or more previous peritonitis episodes and (A) positive P1 antigen, (B) negative Lewis a and positive Lewis b antigens (secretor), or (C) positive Lewis a and negative Lewis b antigens (non-secretor) would be at higher risk of E. coli peritonitis.