Ruichen Guo

Background: Paraquat and diquat are widely used in agricultural production in many countries, which are very toxic to human beings. Paraquat can be detected in some diquat solution sold in the market. The blood concentration of paraquat or diquat is an important indicator for clinical diagnosis of paraquat or diquat poisoning. So, it is very meaningful to develop a method for simultaneous determination of paraquat and diquat in human plasma.Objective: To develop and validate a HPLC‐DAD method for simultaneous determination of paraquat and diquat in human plasma and to apply it in the acute poisoning patients by these two herbicides.Methods: Paraquat and diquat were simultaneously determined by HPLC‐DAD. The plasma was treated using Waters OASIS^® Column and then separated on a Thermo Hypersil GOLD (250 × 4.6 mm, 5 μm) Column with the mobile phase consisted of 75 mmol/L sodium heptane sulfonate (containing 0.1 mol/L phosphoric acid, pH 3.0) and acetonitrile (87:13, v:v) at a flow rate of 1.0 mL/min. The full‐wavelength scanning was 200‐400 nm, and the detection wavelength of paraquat and diquat was 257nm and 310nm, respectively. 120 and 30 plasma samples from patients with paraquat and diquat poisoning were collected and analyzed by the established method.Results: The standard curve for paraquat and diquat ranged from 0.05 to 20 μg/mL, and the precision of LLOQ for paraquat was 16.49%, which was required to be less than 20%. The precision of other concentrations was less than 14.14%. The recovery of paraquat and diquat was 95.38%‐103.97% and 94.79%‐98.40%, respectively. The results showed that paraquat and diquat were stable under various storage conditions. 120 plasma samples of paraquat poisoning patients and 30 plasma samples of diquat poisoning patients were determined by the established method. The blood concentration of paraquat ranged from 0.10 to 20.62 μg/mL, with an average of 3.61 μg/mL, while for diquat, the concentration ranged from 0 to 26.59 μg/mL, with an average of 2.00 μg/mL. Among the diquat suspected poisoning samples, 5 samples were detected not only diquat but also paraquat, and 2 samples were detected only paraquat, no diquat.Conclusion: The HPLC‐DAD method established in this study was high throughput, high sensitivity, simple operation, and wide linear ranges. It can be used for the screening analysis and quantitative detection of paraquat and diquat in acute poisoning patients, which can provide basis for the treatment and prognosis of these two herbicides poisoning patients.

Aim: To evaluate whether the synonymous mutant rs2515641 could affect Cytochrome P450 2E1 (CYP2E1) expression and the response to acetaminophen (APAP) or triptolide (TP) treatment. Materials & meth...

Increased expression of CYP2E1 may represent the main factor contributing to oxidative stress‐mediated liver damage in drug‐induced liver injury (DILI). However, the regulation mechanism of CYP2E1 expression is poorly described. The present study was aimed to investigate the role of CYP2E1 in acetaminophen (APAP)‐ or tripterygium glycosides (TG)‐induced hepatotoxicity as well as the regulation of CYP2E1 and miR‐378a‐3p expression by APAP or TG. Rats were randomly divided and treated with APAP, TG, chlormethiazole (CMZ), APAP + CMZ and TG + CMZ, respectively, for 4 weeks. Then, blood and liver samples were collected. Serum and hepatic biochemical parameters were measured using commercial kits. Liver histopathology was tested by H&E staining. Expression levels of CYP2E1 mRNA and miR‐378a‐3p were detected by qRT‐PCR. CYP2E1 protein expression was determined by Western blot. Our results showed that CMZ effectively restored the hepatic histopathological changes, oxidative stress biomarkers and TNF‐α levels induced by APAP or TG. CYP2E1 mRNA and/or protein expression levels were dramatically increased after chronic APAP or TG treatment, while this induction was significantly reversed by CMZ co‐treatment. Of note, miR‐378a‐3p expression levels were significantly suppressed after APAP, TG and/or CMZ treatment. These results suggested that CYP2E1 were highly induced after chronic APAP or TG treatment, which in turn play an important role in APAP‐ or TG‐induced hepatotoxicity. These inductions of CYP2E1 expression were probably carried out by inhibition of miR‐378a‐3p. Our findings might provide a new molecular basis for DILI.

Background: The impact of antiepileptics on serum vitamin levels is controversial and uncertain. With no clear conclusions on the impact of antiepileptics on serum levels of vitamins, there is a need for further clinical studies in order to ascertain the impact of old and newer antiepileptic drugs on serum levels of vitamins in epileptic patients, thus accomplishing a suitable usage of vitamins supplementation. Objective: The intention of the present research is to confirm the hypothesis of whether or not vitamin levels are altered with antiepileptic drugs. The study also aims to reveal which vitamin levels are particularly more altered, are vitamin levels affected by gender and the type and number of antiepileptics used. Methods: The present research was piloted in collaboration with the Department of Neurology in Qilu Hospital of Shandong University. A total of 63 serum samples of epileptic patients receiving antiepileptics as monotherapy or polytherapy were requested for analysis of nine vitamin serum levels. Total nine vitamins (B1, B2, B6, B9, B12, A, C, D and E) in epileptic patients receiving antiepileptic drugs were analyzed. The serum results of all vitamins were compiled and evaluated with SPSS. Results: It was alarmingly found that serum levels of vitamin D were particularly very low in almost all (90%) epileptic patients in this study. Notably, serum levels of vitamin C and vitamin B1 were also below reference range in 72% and 46% epileptic patients, respectively. The remaining vitamins were almost in reference range for most of the patients. In our study, mean and frequency of vitamin D, C and B1 levels do not vary too much among different gender groups. The patients receiving newer antiepileptic drugs displayed a slightly increased serum vitamin D levels in comparison to the patients receiving older antiepileptic drugs. We found low vitamin D, C and B1 serum levels in patients who were on monotherapy as in comparison with patients on polytherapy. Conclusion: The most significant and surprising finding of this study revealed that serum vitamin D levels in particular were very low in almost all patients and in some patients’ vitamin B1 serum levels were also below the reference range. More importantly, it is first time reported here that vitamin C serum levels were also below reference range in the majority of these Chinese epileptic patients. It is recommended that all these vitamins should be regularly monitored in addition to therapeutic drug monitoring of antiepileptic drugs. Additional clinical trials are required for further evaluation. It is also recommended that epileptic patients with low serum levels of these vitamins may be prescribed vitamins supplementations with antiepileptic drugs in order to control their seizures more effectively and efficiently.

Brusatol, a quassinoid isolated from the traditional Chinese medicine Brucea javanica, has been reported to be an inhibitor of Nrf2 pathway and has great potential to be developed into a novel chemotherapeutic adjuvant. However, the in vivo process of brusatol has not been comprehensively explained yet. Therefore, this paper focused on the pharmacokinetic metabolism and excretion of brusatol in rats using a simple and reproducible LC–MS/MS method. The results indicated that the plasma concentration of brusatol decreased rapidly; the average cumulative excretion rate in urine was 5.82% during 24 h, and 0.71% in bile during 12 h. High‐resolution mass spectrometry was applied for the identification of metabolites; as a result, four metabolites were detected and the structure was tentatively deduced on the base of the MS² data, Compound Discoverer 2.0 and Mass Frontier 7.0 software. Hydroxylation, hydrolysis and glucuronidation were suggested as major metabolic pathways in vivo. The in vivo process and detection of metabolites of brusatol might improve the understanding of the mechanism of its anticancer effect and provide valuable information for its safety estimation, which will be essential to the new drug development.

Background: Tetramethylpyrazine, isolated from Ligusticum wallichii Franch., is widely used for the treatment of cerebrovascular and cardiovascular diseases in China. Objective: To assess and compare the pharmacokinetic characteristics and bioequivalence of two tetramethylpyrazine phosphate (TMPP) tablets in healthy Chinese male subjects. Materials and methods: 20 healthy male subjects were randomly divided into two groups according to a two-period crossover design test. A single oral dose of 200 mg test or reference tablets was given with a 7-day washout period under fasting conditions. Blood samples were taken at scheduled time points, and the concentration of TMPP was measured by LC-MS. Drug And Statistical Software-Version 2.0 was used to calculate the pharmacokinetic parameters and assess bioequivalence of the two formulations. Results: 20 subjects were enrolled in the study, and none dropped out. The main pharmacokinetic parameters of test and reference formulations were as follows: T-1/2 was (1.79 +/- 0.82) hours and (1.64 +/- 0.52) hours, tmax was (0.76 +/- 0.37) hours and (0.94 +/- 0.44) hours, Cmax was (961.14 +/- 309.64) ng/mL and (1,059.09 +/- 350.69) ng/mL, AUC(0-12h) was (1,744.69 +/- 643.49) ngxh/mL and (1,726.32 +/- 494.11) ngxh/mL, AUC(0-8) was (1,756.95 +/- 643.63) ngxh/mL and (1,740.16 +/- 504.89) ngxh/mL, respectively. The relative bioavailability of TMPP tablets was 102.4 +/- 26.0%, and no serious adverse events were reported. Conclusion: This single- dose study in healthy Chinese male fasted subjects showed that the TMPP test and reference tablets were bioequivalent.

The unpredictable and unfavorable connection of dose and plasma concentration of valproic acid supports the necessity to regularly measure its plasma concentration. The present study is drug monitoring of valproic acid and comparative evaluation of therapeutic monitoring results of valproic acid for assessment of clinical response, safety and toxicity in different age and gender groups of Chinese epileptic patients. This knowledge will help the clinicians in adjusting the drug dosages of valproic acid in various sub-groups of epileptic patients for enhancing the safety and minimizing the toxicity of valproic acid. A total of 206 plasma samples (126 males and 80 females) of epileptic patients using valproic acid were requested for therapeutic drug monitoring by neurology department of Qilu Hospital. It was found that 29 % of the total samples were found in sub-therapeutic levels, 13% of the samples had toxic levels and 58% of all the samples had valproic acid levels in therapeutic range. The difference in plasma concentration of valproic acid is notably altered in gender and various age groups. However, this requires further investigation. Despite the majority of samples in the therapeutic range, there was an unfavorable clinical response. The outcomes of the current research work exposed that there was a poor correlation between the plasma concentration and clinical response. Careful attention must be applied to specific gender and particular age group on an individual basis in the interpretation of plasma concentration results, in order to facilitate the modification of doses and develop the best approach in treatment and to obtain the desired clinical response because multiple factors can affect the valproic acid plasma concentration. Through these results, it can be concluded that poor correlation exists between valproic acid plasma concentration and clinical response.

The narrow therapeutic index, non-linear pharmacokinetics and unpredictable absorption require regular therapeutic monitoring of phenytoin. The influence of genetic differences, sex, age and race on the phenytoin plasma levels and its metabolites is well recognized This study is aimed at evaluating phenytoin plasma drug concentration and its relationship with clinical response, persistent seizures and toxicity in different gender and various age groups of Chinese epileptic patients. This knowledge will help the clinicians in adjusting the drug dosages of phenytoin in various sub-groups of epileptic patients for enhancing the safety, efficacy and minimizing the toxicity of phenytoin. A total of 48 plasma samples of epileptic patients for measuring the plasma phenytoin concentration were received. Only patients displaying persistent seizures or suspected of adverse effects were requested for drug monitoring. All these samples were analyzed for therapeutic drug monitoring with Enzyme-multiplied immunoassay technique. Surprisingly, it was found that majorities (85.5%) of samples were out of the reference range, of which 69% of samples were in sub-therapeutic levels and 16.5% of samples were above therapeutic levels. Only 14.5% of all samples had phenytoin levels in the therapeutic range. The difference in plasma concentration of phenytoin was notably altered in gender and various age groups. Careful attention must be applied to specific gender and particular age group on an individual basis in the interpretation of plasma concentration results, in order to facilitate the modification of doses and develop the best approach in treatment and to obtain the desired clinical response because multiple factors can affect the phenytoin plasma concentration. Through these results, it can be concluded that a good correlation exists between phenytoin plasma concentration and clinical response. Therefore, regular therapeutic monitoring of phenytoin and screening of HLA-A, B, C and DRB1 genotypes before prescribing phenytoin in epileptic patients is essentially required to achieve maximum clinical response and prevent the serious toxicity.

An economical, rapid, and sensitive method of gas chromatography-mass spectrometry (GC-MS) was developed and validated to determine the presence of six pesticides (dichlorvos, acetochlor, atrazine, chlorpyrifos, α-endosulfan, and β-endosulfan) in human plasma. The pesticides were extracted with acetonitrile and concentrated using anhydrous sodium sulfate. Then, the target compounds were analyzed and quantified with GC-MS using borneol as an internal standard. Separation was performed on a HP-5MS capillary column (30 m × 0.25 mm × 0.25 µm) with temperature programming. Detection was accomplished under electro-spray ionization (ESI) in selected ion monitoring (SIM) mode. Under optimized conditions, satisfactory linear ranges of 0.05-10 μg/mL were obtained for all of the analyzed pesticides. The linear correlation coefficients were greater than 0.99. The average recovery was between 86.8 and 106.5%. The inter- and intra-day precision ranged from 1.7-14.5% and 4.2-13.8%, respectively. Dichlorvos was unstable in plasma both at room temperature and when frozen. The other five pesticides were stable after storage at – 20°C for 17 days and two freeze-thaw cycles. Thirty-five plasma samples from 15 patients with acute self-poisoning were analyzed using this method. Dichlorvos was found in 13 plasma samples with a mean concentration of 0.289 μg/mL, and atrazine was found in 6 with a mean concentration of 0.261 μg/mL. Acetochlor was found in one plasma sample (0.153 μg/mL). This method is simple, reliable and cost-effective. It takes little time and does not waste solvents, and it can be used to routinely detect six pesticides in patients with acute poisoning.