Determination of Arbutin in Rat Plasma Using Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study After Oral Administration of the Extract of Vaccinium vitis-idaea.

A rapid and sensitive bioassay based on liquid chromatography-tandem mass spectrometry (LC-MS-MS) has been developed and validated to measure arbutin in rat plasma. Sample preparation of plasma after the addition of indapamide as internal standard (IS) involved solid-phase extraction (SPE) on C18 cartridges. Reversed-phase chromatography using acetonitrile and 0.5% formic acid solution (pH 2.56) was used for separation in a run time of 4.0 min. The analytes were detected in the negative ion mode using selective reaction monitoring (SRM) of the transitions at m/z 271.2 → 107.8 for arbutin and 364.3 → 189.0 for indapamide. The method has the following performance characteristics: a reliable response range of 7.5-5250.0 ng/mL with correlation coefficients (r) of >0.995. The lower limit of quantitation (LLOQ) was 7.5 ng/mL. The intra- and inter-day precision and accuracy of the quality control (QC) samples at low, medium and high concentration levels showed ≤8.79% relative standard deviation (RSD) and -1.15 to 1.49% relative error (RE). The method was successfully applied to a pharmacokinetic study to measure arbutin in rats after extracts of Vaccinium vitis-idaea was orally administered.

BCAT1, a key prognostic predictor of hepatocellular carcinoma, promotes cell proliferation and induces chemoresistance to cisplatin.

BACKGROUND & AIMS: BCAT1 initiates the catabolism of branched-chain amino acids. Here, we investigated the function of BCAT1 and its transcriptional regulatory mechanism in hepatocellular carcinoma (HCC). METHODS: RNASeq was used to evaluate BCAT1 mRNA levels in HCC and normal matched specimens. After the exogenous expression of BCAT1 in BEL-7404 cells and the suppression of endogenous BCAT1 expression with shRNA in HepG2 cells, the cell proliferation, clone-forming ability and cell-cycle changes were measured with MTT assay, colony-forming assay and flow cytometry respectively. A xenograft model was used to investigate the effect of BCAT1 on cancer growth in vivo. Chromatin immunoprecipitation and luciferase reporter technologies were used to confirm the transcriptional regulation of the BCAT1 gene by MYC. The expression of the BCAT1 and MYC proteins in 122 HCC tissues was determined with an immunohistochemical analysis. RESULTS: BCAT1 mRNA was clearly increased in HCC tissues and hepatomas. The ectopic expression of BCAT1 in BEL-7404 cells enhanced their proliferation, clone formation, tumourigenic properties, S-G2 /M phase transition and chemoresistance to cisplatin. The suppression of BCAT1 expression in HepG2 cells significantly inhibited their proliferation, clone formation, and S-G2 /M phase transition and caused their chemosensitization to cisplatin. MYC affected the transcriptional regulation of BCAT1. Clinical data showed that BCAT1 expression correlated with a significantly poorer prognosis. CONCLUSION: BCAT1 plays a pathogenic role in HCC by causing cell proliferation and chemoresistance. The MYC transcription factor is involved in regulating the transcriptional activity of BCAT1. BCAT1 expression has prognostic significance for the survival of patients with HCC.

A survey of urolithiasis in young children fed infant formula contaminated with melamine in two townships of Gansu, China.

OBJECTIVE: To determine the prevalence of urolithiasis in young children fed infant formula (IF) contaminated with melamine, and the association between IF consumption and urolithiasis. DESIGN: A total of 2 733 children < or = 3 years of age on September 1, 2008 in two townships of Gansu Province, China were studied. Cases of urolithiasis were diagnosed by ultrasonography. Milk product consumption was determined by their caregivers. Remaining IF samples were tested for melamine and cyanuric acid. RESULTS: Of 2 733 eligible children in the two townships, 2 186 (80%) were enrolled in our study. Overall, 16.6% (362) of 2 186 children had urolithiasis. The prevalence was 24.6% in children exclusively fed Sanlu brand IF, 9.7% in those fed other IF, and 8.5% in those fed exclusively on other milk products. For children exclusively breast-fed, no urolithiasis was found (P < 0.05). The prevalence of urolithiasis was 11.4% in children fed 400 g of Sanlu IF, rising to 37.5% in children fed over 25 600 g. Of 48 Sanlu IF samples, 91.7% contained melamine (median = 1 800 ppm; range = 45-4 700) and 66.7% contained cyanuric acid (median = 1.2 ppm; range = 0.4-6.3). Melamine was also detected in 22.2% of 36 other brand IF (median = 27.5 ppm, range = 4-50). CONCLUSIONS: Urolithiasis was associated with melamine-contaminated IF. Although one product caused most morbidity, other milk products may have also contributed to the outbreak.

Antioxidant inhibits HMGB1 expression and reduces pancreas injury in rats with severe acute pancreatitis.

BACKGROUND: Pathogenesis of severe acute pancreatitis is still unclear, which leads to a lack of proper treatment in severe acute pancreatitis therapeutic strategy. OBJECTIVE: To investigate the effect of treatment with antioxidant pyrrolidine dithiocarbamate on pancreas injury in rats with severe acute pancreatitis and its possible mechanism. METHODS: A total of 144 male Sprague-Dawley rats were randomly allocated into a sham operation group (n=48), a severe acute pancreatitis group (n=48), and a pyrrolidine dithiocarbamate-treated group (n=48). All the rats were killed at 1, 3, 6, 12, 24, and 48 h after operation. The pancreas histopathologies were observed and serum amylase levels were tested. Meanwhile, the nuclear factor-kappaB activation, tumor necrosis factor-alpha levels and high-mobility group box protein-1 expression levels in pancreatic tissue were studied. RESULTS: Animals receiving pyrrolidine dithiocarbamate had significantly improved pancreas histopathology and lower serum amylase levels (p<0.05). In the severe acute pancreatitis group, pancreas tumor necrosis factor-alpha levels reached a peak at 6 h after operation and afterwards rapidly declined to normal levels. However, high-mobility group box protein-1 levels in pancreatic tissue increased remarkably at the 12th hour, reached a peak at 24 h, and maintained up to 48 h post-severe acute pancreatitis. Compared to the severe acute pancreatitis group, the pancreas nuclear factor-kappaB activity, tumor necrosis factor-alpha, high-mobility group box protein-1 levels in the pyrrolidine dithiocarbamate-treated group all remarkably decreased (p<0.05). CONCLUSIONS: High-mobility group box protein-1 seems to act as a late cytokine mediator in the pathogenesis of severe acute pancreatitis. Pyrrolidine dithiocarbamate might inhibit the activation of nuclear factor-kappaB to blockade tumor necrosis factor-alpha, thereby indirectly suppressing the high-mobility group box protein-1 and reducing pancreatic tissue damage in rats with severe acute pancreatitis.

[Experimental therapeutic study for activated coagulation by hemorrhagic shock in rats].

The study was aimed to investigate the changes of blood coagulation factors during hemorrhagic shock in rats and the effects of various of resuscitation fluids on expression of blood coagulation factors in rats with hemorrhagic shock and to clarify its possible mechanism. 50 SD rats were randomly divided into 5 groups: control, sham operation, shock, resuscitation 1 (infusion with Ringer's lactate) and resuscitation 2 (infusion with 6% VOLUVEN), 10 rats per group. The rats in resuscitation 1 and resuscitation 2 groups were subjected to hemorrhagic shock, after hemorrhage shock for 1 hour resuscitation was performed with Ringer's lactate and 6% VOLUVEN. After resuscitation for 2 hours the changes of t-PA, PAI-1, TF were measured. At the same time, the rats in shock and the sham operation groups were blooded out so as to test. The results showed that the levels of plasma t-PA, t-PA/PAI, TF in the shock and resuscitation 1 groups were significantly higher than that in control and sham operation groups (P<0.01). The levels of plasma t-PA, t-PA/PAI in resuscitation 1 group were higher than that in shock group (P<0.01), the levels of plasma t-PA, t-PA/PAI and TF in the resuscitation 2 group were significantly lower than that in shock and resuscitation 1 groups (P<0.01). It is concluded that hemorrhagic shock may trigger the coagulation cascade reaction, results in hyperfunctioning of fiberinolysis and activation of platelets and coagulation system, and so the coagulation factor is greatly consumed. Unbalance of coagulation system plays an important role in the progress of shock. Efficacy of resuscitation with 6% VOLUVEN plus Ringer's lactate may be better than Ringer's lactate alone in regulating blood coagulation after hemorrhagic shock in rats.