Simultaneous determination of diquat, paraquat, glufosinate, and glyphosate in plasma by liquid chromatography/tandem mass spectrometry: from method development to clinical application.

Diquat (DQ), paraquat (PQ), glufosinate (GLU), and glyphosate (GLYP) are commonly used herbicides that have been confirmed to be toxic to humans. Rapid and accurate measurements of these toxicants in clinical practice are beneficial for the correct diagnosis and timely treatment of herbicide-poisoned patients. The present study aimed to establish an efficient, convenient, and reliable method to achieve the simultaneous quantification of DQ, PQ, GLU, and GLYP in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS) without using derivatization or ion-pairing reagents. DQ, PQ, GLU, and GLYP were extracted by the rapid protein precipitation and liquid-liquid extraction method and then separated and detected by LC-MS/MS. Subsequently, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, extraction recovery, matrix effect, dilution integrity, and stability were evaluated to validate the method based on the FDA criteria. Finally, the validated method was applied to real plasma samples collected from 166 Chinese patients with herbicide poisoning. The results showed satisfactory linearity with low LOD (1 ng/mL for DQ and PQ, 5 ng/mL for GLU, and 10 ng/mL for GLYP, respectively) and low LOQ (5 ng/mL for DQ and PQ, 25 ng/mL for GLU and GLYP, respectively). In addition, the precision, accuracy, extraction recovery, and stability of the method were acceptable. The matrix effect was not observed in the analyzed samples. Moreover, the developed method was successfully applied to determine the target compounds in real plasma samples. These data provided reliable evidence for the application of this LC-MS/MS method for clinical poisoning detection.

Vitamin D supplementation reduced blood inflammatory cytokines expression and improved graft function in kidney transplant recipients.

Background: Chronic allograft dysfunction(CAD) is the leading cause of graft loss in kidney transplant recipients (KTRs). Inflammatory process is believed to be one of the major contributors to CAD. The aim of this study is to explore the anti-inflammatory effect of vitamin D (VD) supplementation in KTRs and its role in the graft function improvement(protection). Methods: A retrospective cohort of 39 KTRs with chronic antibody mediated rejection(CAMR)or stable renal function and a prospective cohort of 42 KTRs treated or untreated with VD were enrolled. Serum levels of vitamin D metabolism and serum inflammatory cytokines, renal graft function, and routine blood biomarkers were tested and dynamically tracked within 12 months post-transplant. Results: Compared with the stable group, the CAMR group exhibited significantly elevated serum levels of inflammatory cytokines IL-1ß, IFN-γ, IL-2, IL-10, IP-10, and HMGB1 (P <0.05). The supplementation of vitamin D effectively increased the serum concentration of vitamin D in kidney transplant recipients (KTRs) in the treated group. During the course of treatment, the treated group exhibited a gradual increase in eGFR levels, which were significantly higher than those observed in the untreated group at 12 months post-transplant (p<0.05). Notably, as eGFR improved, there was a significant decrease in levels of IL-1ß, IFN-γ, IL-2, IL-10, IP-10 and HMGB1 in the treated group compared to the untreated group (P<0.05). Conclusion: This study confirmed that immune-inflammation is a crucial factor in the development of CAD in KTRs.VD deficiency impairs its anti-inflammatory activity. By assisting in the regulation of excessive immune inflammation and restoration of immune homeostasis, effective VD supplementation contributes to protection and maintenance of graft function in KTRs.

Metabolomics profile of plasma in acute diquat-poisoned patients using gas chromatography-mass spectrometry.

Diquat (DQ) has been confirmed to be toxic to humans and responsible for severe health impairment. While to date, very little is known about the toxicological mechanisms of DQ. Thus, investigations to discover the toxic targets and potential biomarkers of DQ poisoning are urgently needed. In this study, a metabolic profiling analysis was conducted to reveal the changes of metabolites of plasma and find out the potential biomarkers of DQ intoxication by GC-MS. First, multivariate statistical analysis demonstrated that acute DQ poisoning can lead to metabolomic changes in human plasma. Then, metabolomics studies showed that 31 of the identified metabolites were significantly altered by DQ. Pathway analysis indicated that three primarily metabolic pathways including phenylalanine, tyrosine and tryptophan biosynthesis, taurine and hypotaurine metabolism, and phenylalanine metabolism were affected by DQ, resulting in the perturbations of phenylalanine, tyrosine, taurine, and cysteine. Finally, the results of receiver operating characteristic analysis showed the above four metabolites could be used as reliable tools for the diagnosis and severity assessments of DQ intoxication. These data provided the theoretical basis for basic research to understand the potential mechanisms of DQ poisoning, and also identified the desirable biomarkers with great potential for clinical applications.

Altered Serum Bile Acid Profile Associated with Chronic Allograft Dysfunction in Kidney Transplant Recipients.

BACKGROUND Chronic allograft dysfunction (CAD) is the leading cause of graft loss among kidney transplant recipients (KTRs). Bile acids (BAs) play an important role in regulating inflammatory process, which is the major contributor to the development of CAD. The aim of this study was to evaluate the association between BAs metabolic dysregulation and CAD in KTRs. MATERIAL AND METHODS Fifteen serum BA species were determined in 43 healthy controls (HCs) and 131 KTRs by UPLC-MS/MS. KTRs were grouped into stable renal function (STA) and CAD1 and CAD2 groups based on eGFR levels. Circulating CYP7A1, CYP7B1, CYP27A1, and SLCO2B1 mRNA levels were determined by RT-PCR. RESULTS Total BA concentrations were comparable among the 4 groups. However, KTRs showed significantly different BAs profiling compared to HCs. KTRs with severe CAD (CAD2) had significantly lower unconjugated BAs and secondary BAs (SBAs) compared to the other 3 groups. KTRs had significantly lower SBAs/primary BAs (PBAs) ratios than HCs, which were comparable among the 3 KTR groups. Conjugated/unconjugated BAs ratios increased significantly with the deterioration of allograft function, which was further confirmed by correlation analysis. Differential correlation network analysis revealed that perturbations in intraclass and interclass BA coregulation existed during CAD progression. Moreover, relative gene expressions of CYP7B1 and CYP27A1 were positively correlated with eGFR. CONCLUSIONS BA species profiling, but not total BA concentrations, was significantly altered in KTRs with CAD. The shifts from unconjugated BAs toward conjugated BAs, SBAs toward PBAs, and distinct pairwise BAs coregulation patterns were the main characteristics of KTRs with CAD.

Association of genetic variants in TPMT, ITPA, and NUDT15 with azathioprine-induced myelosuppression in southwest china patients with autoimmune hepatitis.

This study aimed to investigate the influence of TPMT*3C, ITPA, NUDT15, and 6-thioguanine nucleotides (6-TGN) on azathioprine (AZA)-induced myelosuppression in Southwest China patients with autoimmune hepatitis (AIH). A total of 113 Chinese patients with AIH receiving AZA maintenance treatment were evaluated. The relevant clinical data of the patients were collected from the hospital information system. Genotyping of TPMT*3C(rs1142345), ITPA (rs1127354) and NUDT15(rs116855232) was conducted using a TaqMan double fluorescent probe. The concentration of 6-TGN was determined using UPLC-MS/MS. Among AIH patients treated with AZA, 40 (35.4%) exhibited different degrees of myelosuppression. The NUDT15 variant was associated with leukopenia (P = 8.26 × 10-7; OR = 7.5; 95% CI 3.08-18.3) and neutropenia (P = 3.54 × 10-6; OR = 8.05; 95% CI 2.96-21.9); however, no significant association with myelosuppression was observed for TPMT*3C and ITPA variants (P > 0.05). There was no significant difference in 6-TGN concentration between AIH patients with or without myelosuppression (P = 0.556), nor was there a significant difference between patients with variant alleles of TPMT*3C, ITPA, or NUDT15 and wild-type patients (P > 0.05). Interestingly, it was found that patients with a lower BMI had higher adjusted 6-TGN levels and a higher incidence of myelosuppression (P = 0.026 and 0.003). This study confirmed that NUDT15 variants are a potential independent risk predictor for AZA-induced leukopenia and neutropenia. BMI may be a crucial non-genetic factor that affects the concentration of AZA metabolites and myelosuppression. In addition, the 6-TGN concentration in red blood cells does not reflect the toxicity of AZA treatment, and new biomarkers for AZA therapeutic drug monitoring need further research.

Highly sensitive and rapid determination of azathioprine metabolites in whole blood lysate by liquid chromatography-tandem mass spectrometry.

Individualized therapy involves genetic test of drug metabolism, which provides information about the initial dose and therapeutic drug monitoring for adjusting the subsequent dose. Consequently, toxic side effects are expected to be minimized and therapeutic effects to be maximized. In this study, an ultra-performance liquid chromatography tandem mass spectrometry method that was specific, accurate and sensitive was developed to simultaneously determine azathioprine two metabolites, 6-thioguanine nucleotides (6-TGN) and 6-methyl-mercaptopurine riboside (6-MMPr) in the whole blood lysate. We precipitated the sample by trifluoroacetic acid under the protection of dithiothreitol, with 6-MMPr and 6-TGN being hydrolyzed to produce 6-methymercaptopurine and 6-thioguanine. In the chromatographic separation, Waters ACQUITY BEH C18 (2.1 × 100 mm, 1.7 µm) chromatographic column was applied and gradient elution was conducted with 0.02 mol/L ammonium acetate buffer (which contains 0.3% formic acid) and acetonitrile at a flow rate of 0.4 ml/min. Tandem mass spectrometry in multiple reaction monitoring mode was applied for detection via electrospray ionization source in positive ionization mode. The analyzing process lasted for no more than 2 min. The calibration curve for each metabolite fitted a least squares model (weighed 1/X) from 1.25 to 5000 ng/ml (r2 > 0.99). The ion pairs were detected as 6-MMP m/z 167.07 â†’ 152.15, 6-TG m/z 168.06 â†’ 134.13, and internal standard m/z 171.07 â†’ 137.14. Under the guidance of FDA guidelines for bioanalytical method validation, we carried out validation and obtained satisfactory results. The method was successfully utilized for monitoring the concentrations of each metabolite from 65 affected patients who had received azathioprine maintenance therapy and achieved optimal results.

Correlation of CYP2C19 genotype with plasma voriconazole exposure in South-western Chinese Han patients with invasive fungal infections.

The aim of this study was to investigate the correlation between CYP2C19 genotype and dose-adjusted voriconazole (VCZ) trough concentrations (C0/dose).We analyzed the correlation between CYP2C192(681G>A), CYP2C193(636G>A), and CYP2C1917(-806C>T) genetic polymorphisms and the dose-corrected pre-dose concentration (C0/dose) in 106 South-western Chinese Han patients.The frequencies of variant alleles of CYP2C192, 3, and 17 were 29.7%, 4.25%, and 0.92%. For 49.3% of the VCZ samples, the therapeutic window between 1.5 and 5.5 µg/ml was reached. Following the first dose VCZ measurement, in subsequent samples the proportion of VCZ C0 within the therapeutic window increased, suggesting effective therapeutic drug monitoring (TDM) (P = .001). The VCZ C0 was significantly different (P = .010) between patients with normal metabolism (NMs), intermediate metabolism (IMs), and poor metabolism (PMs). The VZC C0/dose was 12.2 (interquartile range (IQR), 8.33-18.2 µg·ml/kg·day), and 7.68 (IQR, 4.07-16.3 µg·ml/kg·day) in PMs and IMs patients, respectively, which was significantly higher than in NMs phenotype patients (4.68; IQR, 2.51-8.87 µg·ml/kg·day, P = .008 and P = .014).This study demonstrated that the VCZ C0/dose was significantly influenced by the CYP2C19 genotype in South-western Chinese Han patients. In this patient population, more over-exposure was observed in patients with a CYP2C19 genotype associated with poor or intermediate metabolism. CYP2C19 genotype-based dosing combined with TDM will support individualization of VCZ dosing, and potentially will minimize toxicity and maximize therapeutic efficacy.

A Low Fixed Tacrolimus Starting Dose Is Effective and Safe in Chinese Renal Transplantation Recipients.

BACKGROUND We investigated whether a low fixed Tac starting dose regimen could lead to a better achievement of Tac target concentrations, as well as an effective immunosuppressive treatment, in Chinese kidney transplant recipients (KTRs). MATERIAL AND METHODS We collected whole-blood and serum samples from 189 KTRs and the Tac starting dose was 2, 2.5, or 3 mg/day. Information on Tac C0, dose, body weight, body mass index (BMI), Scr, eGFR, and CYP3A5 genotypes were collected from a routine therapeutic drug monitoring database. The correlation between Tac C0 and body weight (or BMI) was investigated by calculating the goodness of fit. Multivariable logistic regression was performed to estimate the independent associated factors. RESULTS The patients with 3 mg per day of Tac had higher C0 at day 7 compared to those with 2 or 2.5 mg. For patients receiving the same Tac starting dose, no significant difference was found in Tac C0 at day 7 among different body weight or BMI groups. There was no significant difference in Scr or eGFR at 1 year after transplant, nor was there a significant difference in the rates of DGF or AR at post-transplant day 30 among different Tac starting dose groups or among the 3 Tac C0 range groups. CYP3A5 genotype and Tac initial dose were independently associated with Tac C0. CONCLUSIONS CYP3A5 genotype and Tac initial dose were independently associated with Tac C0 in renal transplant recipients. Our results suggest that a low Tac target C0 range (5-8 ng/ml) with a low fixed starting dose (3 mg/day) would be safe and effective among Chinese KTRs.

Urinary 8-oxo-7,8-dihydroguanosine as a Potential Biomarker of Aging.

Background: A molecular biomarker of physiologic age, as opposed to chronologic age, is needed in clinical medicine. 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGsn) and 8-oxo-7, 8-dihydroguanosine (8-oxoGsn) are two promising aging biomarkers. Methods: A total of 1,228 healthy Chinese residents (613 males and 615 females) 2-90 years of age were randomly selected. Spot urine samples were collected, and the concentrations of 8-oxodGsn and 8-oxoGsn were measured using ultra-high-performance liquid chromatography with a triple quadrupole mass spectrometer (UPLC-MS/MS). Method validation, including accuracy, precision, linearity and quantification limit, was performed. The relationship between oxidized guanosine and age/gender was evaluated. Results: 8-oxodGsn and 8-oxoGsn were eluted at 1.61 and 1.30 min, respectively. The calibration curve was linear in the range of 0.2-500 ng/ml for both analytes. The lowest limit of quantification (LLOQ) was 0.2 ng/ml for 8-oxodGsn and 0.1 ng/ml for 8-oxoGsn. There was an age-dependent increase in the biomarkers from the 21- to 30-year-old group to the 81- to 90-year-old group in both genders. In the subjects older than 61 years of age, the levels of 8-oxodGsn as well as 8-oxoGsn in urine were much higher in females than in males. The content of 8-oxoGsn correlated more closely with age and was higher (approximately 2-fold) than that of 8-oxodGsn for a given individual. Conclusions: 8-oxodGsn and 8-oxoGsn can be easily measured by UPLC-MS/MS. Urinary 8-oxoGsn may be a potential biomarker to determine a person's physiologic age and identify individuals at high risk of developing age-associated disease.

Elevated Levels of Urinary Markers of Oxidative DNA and RNA Damage in Type 2 Diabetes with Complications.

The mechanisms underlying progression of type 2 diabetes are complex and varied. Recent studies indicated that oxidative stress provided a new sight. To further assess the relationship between nucleic acid oxidation and complications in patients with type 2 diabetes and explore its possible molecular mechanisms, we studied 1316 subjects, including 633 type 2 diabetes patients and 683 age- and sex-matched healthy controls. Urinary levels of DNA oxidation marker 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and RNA oxidation marker 8-oxo-7,8-dihydroguanosine (8-oxoGuo) were measured by ultraperformance liquid chromatography and mass spectrometry (UPLC-MS/MS). Serum glucose, HbA1c, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides (TG) were also determined. The results showed significantly elevated levels of both the urinary 8-oxodGuo and 8-oxoGuo in diabetes patients with/without complications compared with age-matched healthy control subjects (p = 0.02 and p < 0.001, resp.). Patients with complications, especially macrovascular complications, exhibited higher levels of 8-oxoGuo than those without complications, while there was no difference in the concentrations of serum glucose and lipids. The finding indicates the role for oxidative damage to DNA and RNA, as a molecular mechanism contributing to the progression of type 2 diabetes. Elevated levels of 8-oxoGuo may be a risk factor for type 2 diabetes complications, especially in diabetic macrovascular complications.

Warfarin dosage response related pharmacogenetics in Chinese population.

OBJECTIVES: As the most frequently prescribed anticoagulant, warfarin has large inter-individual variability in dosage. Genetic polymorphisms could largely explain the differences in dosage requirement. rs9923231 (VKORC1), rs7294 (VKORC1), rs1057910 (CYP2C9), rs2108622 (CYP4F2), and rs699664 (GGCX) involved in the warfarin action mechanism and the circulatory vitamin K were selected to investigate their polymorphism characteristics and their effects on the pharmacodynamics and pharmacokinetics of warfarin in Chinese population. METHODS: 220 patients with cardiac valve replacement were recruited. International normalized ratio and plasma warfarin concentrations were determined. The five genetic polymorphisms were genotyping by pyro-sequencing. The relationships of maintenance dose, plasma warfarin concentration and INR were assessed among groups categorized by genotypes. RESULTS: rs9923231 and rs7294 in VKORC1 had the analogous genotype frequencies (D': 0.969). 158 of 220 recruited individuals had the target INR (1.5-2.5). Patients with AA of rs9923231 and CC of rs7294 required a significantly lower maintenance dose and plasma concentration than those with AG and TC, respectively. The mean weekly maintenance dose was also significantly lower in CYP2C9 rs1057910 mutated heterozygote than in patients with the wild homozygote. Eliminating the influence from environment factors (age, body weight and gender), rs9923231 and rs1057910 could explain about 32.0% of the variability in warfarin maintenance dose; rs7294 could explain 26.7% of the variability in plasma concentration. For patients with allele G of rs9923231 and allele T of rs7294, higher plasma concentration was needed to achieve the similar goal INR. CONCLUSIONS: A better understanding of the genetic variants in individuals can be the foundation of warfarin dosing algorithm and facilitate the reasonable and effective use of warfarin in Chinese.

[Association of CYP3A5 and MDR1 genetic polymorphisms with the blood concentration of tacrolimus in Chinese liver and renal transplant recipients].

OBJECTIVE: To investigate the association of CYP3A5 and MDR1 genetic polymorphisms with the concentration/ dose (C/D) ratio of tacrolimus for the feasibility of individualized medication. METHODS: The concentration of tacrolimus was detected by enzyme-multiplied immunoassay technique, and was adjusted by weight and dosage to C/D ratios. The single nucleotide polymorphisms of CYP3A5 A6986G and MDR1 C3435T, G2677T/ A, T1236C were determined by TaqMan RT-PCR. The differences of C/D ratio were compared among all of the genotype groups. RESULTS: There were 5 cases with CYP3A5 *1/*1, 22 cases with CYP3A5 *1/*3, and 33 cases with CYP3A5 *3/*3. The C/D ratios of the patients with at least one CYP3A5 *1 allele (130.40 +/- 53.94) was significantly lower than those with CYP3A5 *3/*3 (198.12 +/- 90.80) (P < 0.01). For MDR1, there were 22, 23 and 15 recipients carried C/C, C/T and T/T respectively in C3435T, and 8, 32 and 20 recipients carried T/T, T/ C and C/C respectively in T1236C. The carriers with G/G, G/T, G/A, T/A, T/T were 9, 24, 5, 8 and 14 respectively in G2677T/A. No significant difference was found in the C/D ratios of tacrolimus among different MDR1 genotypes. CONCLUSIONS: Determination of CYP3A5 genotype could help individualize tacrolimus dose regimen prospectively. The patients with CYP3A5 *3 *3 require less dose of tacrolimus to reach the same concentrations comparing with the patients with at least one CYP3A5 * 1 allele.

Influence of CYP3A4, CYP3A5 and MDR-1 polymorphisms on tacrolimus pharmacokinetics and early renal dysfunction in liver transplant recipients.

OBJECTIVES: Tacrolimus is a widely used immunosuppressive drug in organ transplantation. The oral bioavailability of tacrolimus varies greatly between individuals and depends largely on the activity of both the cytochrome P450 3A (CYP3A) subfamily and P-glycoprotein (P-gp). The possible influence of single nucleotide polymorphisms (SNPs) of CYP3A subfamily and P-gp (MDR-1) in liver transplant recipients has recently been indicated as one of the most important variables affecting the pharmacokinetics of tacrolimus and the renal injury induced by tacrolimus. METHODS: A total of 216 liver transplant recipients were enrolled in this study. The recipients' mean follow-up time was 52 mo (range from 16 to 96 mo). All liver transplant recipients were all in a stable stage with normal serum creatinine (SCr). All liver transplant recipients treated with tacrolimus were genotyped for CYP3A5 (6986A>G), CYP3A4 intron 6 (CYP3A4*22), MDR-1 exon 26 (3435C>T) and exon 12 (1236 C>T) SNPs by HRM analysis (high-resolution melting curve analysis). Recipients were defined as the early renal injury by the elevation of different microproteins in the urine including microalbumin (MA), urine immunoglobulin G (IGU), urine transferrin (TRU) and α1-microglobulin (A1M). RESULTS: The daily dose of tacrolimus was higher for recipients with CYP3A5 1/1 (AA) genotype than those with CYP3A5 3/ 3 (GG) genotype [3.0 (2.0-4.0) versus 2.0 (1.5-2.5) mg/d, P<0.05]. The concentration/dose ratio of recipients with CYP3A5 1 homozygotes was lowest compared to recipients with CYP3A5 3/ 3 and CYP3A5 1/ 3 genotypes. Furthermore, the recipients carrying CYP3A5 3 allele were associated with increased risk of early renal glomerular injury compared to the recipients carrying CYP3A5 1 allele (P=0.01). MDR-1 polymorphisms were not related with tacrolimus pharmacokinetics and early renal injury. CONCLUSION: CYP3A5 6986A>G genetic polymorphism affected daily dose requirements, concentration and nephrotoxicity of tacrolimus. Screening for this single nucleotide polymorphism before the transplantation might be helpful for the selection of adequate initial daily dose and to achieve the desired immunosuppression outcome.

Sirolimus-based regimen promotes inhibitory costimulatory signal of HVEM/BTLA/CD160/LIGHT pathway in allo-renal recipients.

HVEM/BTLA/CD160/LIGHT pathway is a very special costimulatory molecule system which can regulate T-cell immune responses by activating both inflammatory and inhibitory signalings. The regulatory effect of Sirolimus on HVME costimulatory system in allo-renal recipients has not been reported. In this study, we analyzed the expression of HVEM, BTLA, CD160 and LIGHT on circulating T cell subgroups and the expression of HVEM on CD4+ Tregs by flow cytometry and also the pre-dose concentration of Sirolimus by automatic analyzer. Both the allo-renal recipients receiving Sirolimus immunosuppressive regimen and health volunteers were included. The expression of both BTLA and CD160 on T cells increased significantly while the expression of LIGHT on T cells decreased significantly in allo-renal recipients receiving Sirolimus regimen (p<0.05). The expression of HVEM on T cells and CD4+ T-cell subgroup decreased (p<0.05) while that on CD8+ T-cell subgroup remained roughly normal (p>0.05).The expression of HVEM on CD4+ Tregs increased significantly (p<0.05) in allo-renal recipients receiving Sirolimus regimen (p<0.05). Though regulating the expression of HVEM/BTLA/CD160/LIGHT costimulatory system, Sirolimus-based regimen promotes inhibitory costimulatory signal in T cells and enhances the function of CD4+ Tregs in allo-renal recipients, which are in benefit of the control of transplant rejection as well as the induction and maintenance of transplant tolerance.

The value of plasma paraquat concentration in predicting therapeutic effects of haemoperfusion in patients with acute paraquat poisoning.

OBJECTIVE: This study was aimed to analyze the scavenging effect of haemoperfusion on plasma paraquat (PQ) and to evaluate the clinical significance of PQ examination in the treatment of patients with acute paraquat poisoning. METHODS: 85 patients with acute paraquat intoxication by oral ingestion were admitted in West China Hospital from Jun, 2010 to Mar, 2011. A standardized therapeutic regimen including emergency haemoperfusion was given on all subjects. A total of 91 whole blood samples were taken before (0 h), underway (1 h after haemoperfusion beginning) and at the end (2 h) of the haemoperfusion therapy. The clearance rate was calculated and related factors were analyzed. RESULTS: As heamoperfusion was going on, the plasma paraquat concentration of the patients kept falling down. After 1 hour of haemoperfusion, the average clearance rate (R(1)) was 37.06±21.81%. After 2 hours of haemoperfusion, the average clearance rate (R(2)) was 45.99±23.13%. The average of R(1)/R(2) ratio was 76.61±22.80%. In the high paraquat concentration group (plasma paraquat concentration (C(0)) >300 ng/mL), both the averages of R(1) and R(2) were significantly higher than those of the low paraquat concentration group (C(0)≤200 ng/mL) (p<0.05), and there was no significant difference of R(1)/R(2) between these two groups (p>0.05). CONCLUSIONS: The dynamic monitoring of plasma PQ concentration was not only critical in the clinical evaluation but also helpful in guiding the treatment of patients with acute PQ intoxication. Haemoperfusion can effectively eliminate paraquat from the plasma in patients with high initial plasma PQ concentration, while in patients with low initial plasma PQ concentration (<200 ng/ml), the clearance effect of harmoperfusion was very limited. Increasing HP time might improve the overall clearance rate of HP on plasma PQ yet decrease the elimination efficiency of HP, while repeated HP treatment was helpful against the rebound phenomena.

Impact of tacrolimus on bone metabolism after kidney transplantation.

Bone disease is a common clinical problem after kidney transplantation. To date, studies investigating the effects of tacrolimus (TAC) on bone metabolism in vivo or vitro yielded conflicting data. This study was carried out to discuss the relationship between TAC blood concentrations and bone metabolism status in kidney transplant recipients. 72 kidney recipients whose time since transplantation more than 5 months (5-51 months) were divided into two groups by the TAC blood concentrations, high TAC group (TAC≥6 ng/mL) and low TAC group(TAC<6 ng/mL), respectively. Bone mineral density (BMD) of lumbar vertebrae L1-L4 and neck of the femur and allied biochemical markers (TRAP-5b, B-ALP, 25-(OH)D, PTH, beta-CrossLaps, N-MID Osteocalcin, Ca, PO4) were measured simultaneously. Our results showed that 27.78% of our patients had bone loss and the loss rates were statistical different between the high TAC group and low TAC group in kidney recipients (45.5% vs 20.0%, P=0.026). Correlation analysis showed that TAC concentrations were positively correlated with tartrate-resistant acid phosphatase-5b (TRAP-5b) in male recipients (r=0.287, P<0.05). In conclusion, kidney transplant recipients with high TAC blood concentrations are at risk of bone loss, and TAC may cause bone disorders involved in accelerated bone resorption.

The associations of IL-18 serum levels and promoter polymorphism with tacrolimus pharmacokinetics and hepatic allograft dysfunction in Chinese liver transplantation recipients.

Interleukin 18 (IL-18) is a potent proinflammatory cytokine, which promotes the secretions of TNF-α, IL-1ß, IL-2 and IFN-γ. All those inflammatory cytokines can influence the CYP450 and MDR dependent drug disposition. On the other side, those cytokines can induce hepatic allograft dysfunction. We investigated the effects of serum IL-18 and IL-18 gene promoter polymorphisms on tacrolimus pharmacokinetics and hepatic allograft dysfunction in liver transplant recipients. A total of 155 liver transplant recipients were enrolled into this study (34 females and 121 males). The mean follow-up was 52 months (range 16-96 months).The total liver transplant recipients were divided into hepatic allograft dysfunction (N=14) and no hepatic allograft dysfunction (N=141). We studied two single-nucleotide polymorphisms in the promoter region of IL-18 gene at the position G-137C (rs187238) and A-607C (rs1946518) by HRM analysis (high-resolution melting curve analysis). Tacrolimus dosage, tacrolimus blood concentration, serum levels of IL-18 and IFN-γ were also investigated. We found the recipients with higher IL-18 and IFN-γ serum levels had lower tacrolimus concentration/dose (C/D) ratios (P<0.05). In the mean time, after transplantation hepatic allograft dysfunction was more likely to happen to those recipients. However, there was no significant difference in the frequencies of A-607C and G-137C allelic distribution in recipients' tacrolimus concentration/dose (C/D) ratios. This study identifies IL-18 reduced tacrolimus concentration/dose (C/D) ratio through up regulation of P-glycoprotein (P-gp).

An improved approach for extraction and high-performance liquid chromatography analysis of paraquat in human plasma.

A simple, sensitive, reliable and economical HPLC method for quantifying paraquat concentration in human plasma has been developed, using diethyl paraquat as an internal standard. The drugs were extracted from the sample and separated on Xtimate C18 column with a mobile phase of 15% acetonitrile in 0.1M orthophosphoric acid containing SDS (150 mg/l). The pH of the mobile phase was adjusted to 3 with triethylamine and the detection wavelength was 256 nm for both paraquat and the internal standard. The average extraction recoveries were 91.9%. Good linearity (R(2)=0.9984) was observed throughout the range of 0.02-10 µg/ml in 0.5 ml plasma. The overall accuracy of this method was 97.6-107.3% and the lower limit of detection was 0.01 µg/ml. The intra- and inter-day variations were lower than 3.65% and 2.64%, respectively. We used this method to examine the paraquat concentrations of 53 patients with acute paraquat intoxication of whom 26 (49.1%) survived. In conclusion, this method was suitable for quantification of paraquat plasma concentration in toxicological samples. It was helpful in both assessing the severity of intoxication and predicting the outcome of paraquat poisoning.

Modulation of human bronchial epithelial cells by pneumococcal choline binding protein A.

Choline binding protein A (CbpA) is an important adhesin and a determinant of virulence for Streptococcus pneumoniae. Binding to epithelial cells of host mucosal surfaces by pneumococcal CbpA is essential for pneumococcus to initiate colonization and to trigger subsequent invasive pneumococcal infections. In this study, we examined the immunopathologic mechanisms for the activation of human bronchial epithelial cells by CbpA in pneumococcal infections. Adhesion molecules, cytokines, and chemokines were assessed by flow cytometry, quantitative real-time polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively. Intracellular signaling molecules were investigated by enzyme-linked immunosorbent assay or transcription factor assay. CbpA could upregulate cell surface expression of adhesion molecule intercellular adhesion molecule-1 on human bronchial epithelial cells. CbpA could also induce the release of inflammatory cytokine interleukin-6, and chemokines CCL2, CXCL1, and CXCL8 from human bronchial epithelia cells. CbpA-mediated induction of these mediators was differentially regulated by extracellular signal-regulated kinase, c-Jun N-terminal protein kinase, p38-mitogen-activated protein kinase, and nuclear factor-κB pathways. CbpA was also found to participate in the induction of IL-6, CCL2, CXCL1, and CXCL8 in the airways of mice upon intranasal challenge with S. pneumoniae. Our study therefore suggests that pneumococcal CbpA plays an immunopathophysiologic role by activating human bronchial epithelial cells in pneumococcal infections.

Pharmacokinetics of acamprosate calcium in healthy Chinese subjects after oral administration of three dosage levels.

To study the pharmacokinetics of acamprosate calcium (CAS 77337-73-6) in healthy Chinese subjects after oral administration of three dosage levels, 12 healthy subjects were divided into three groups and given a single oral dose of 333 or 666 or 1332 mg acamprosate calcium (enteric coated tablet). A sensitive liquid chromatography-tandem mass spectrometry method (LC-MS-MS) was used for the determination of acamprosate calcium in plasma. Both, a non-compartmental and compartmental method were used for analysis of kinetics parameters. The main pharmacokinetic parameters of the 333, 666 and 1322 mg regimen groups were as follows: tmax 7.5 +/- 2.6 h, 7.4 +/- 2.2 h, 8.1 +/- 3.1 h, Cmax 134.8 +/- 103.9 ng/mL, 297.5 +/- 188.1 ng/mL, 385.4 +/- 155.7 ng/mL, t1/2 13.3 +/- 11.4 h, 17.9 +/- 18.1 h, 15.1 +/- 9.1 h, AUC(0-t) 1772 +/- 1323 ng x h/mL, 3709 +/- 1195 ng x h/mL, 6421 +/- 2486 ng x h/mL, respectively. Statistical analysis of AUC/D showed that AUCs increased linearly with the administered dose. The kinetic process of acamprosate calcium was best fitted to a one-compartment model.