Chloroplast clustering around the nucleus induced by OMP24 overexpression unexpectedly promoted PSTVd infection in Nicotiana benthamiana.

Chloroplast clustering around the nucleus is a well-known mechanism that occurs in response to various biotic and abiotic stresses and is believed to be a mechanism of defence against pathogens in plants. This phenomenon is accompanied by increased production of reactive oxygen species (ROS), which can help to destroy invading pathogens. However, the function of chloroplast clustering during viroid infection is unclear. Here, we report that, although the infection by potato spindle tuber viroid (PSTVd) failed to induce chloroplast clustering, chloroplast clustering caused by the overexpression of the Nicotiana benthamiana chloroplast outer membrane protein 24 (NbOMP24) promoted the infection by PSTVd, a viroid pathogen, in N. benthamiana. Interestingly, H2 O2 treatment, which caused increased ROS accumulation, showed no significant effects on PSTVd infection. Moreover, NbOMP24 protein showed no direct interaction with PSTVd. We propose that perinuclear chloroplast clustering induced by NbOMP24 provides a favourable environment for PSTVd infection. These findings highlight the complexity of chloroplast clustering-mediated plant-pathogen interactions and the need for further research to fully understand these mechanisms.

The Additional 15 nt of 5' UTR in a Novel Recombinant Isolate of Chilli Veinal Mottle Virus in Solanum nigrum L. Is Crucial for Infection.

An isolate of chilli veinal mottle virus (ChiVMV; genus Potyvirus) of Solanum nigrum L. from southwest China (ChiVMV-YunN/Yuxi) was identified and sequenced (GenBank: OP404087). Comparison with other ChiVMV isolates and recombination analyses suggested a recombinant origin. The most significant recombination event among all 21 complete ChiVMV isolates was an ending breakpoint at 1408-1488 for ChiVMV-YunN/Yuxi with ChiVMV-TaiW and ChiVMV-YunN/Ca operating as the respective major and minor parents. Interestingly, the 5' UTR of ChiVMV-YunN/Yuxi is 15 nucleotides ('AAAAATAAAACAACC') longer than other reported isolates. A full-length clone of ChiVMV-YunN/Yuxi was constructed and was shown to be infectious in Nicotiana benthamiana. The additional 15 nt of 5' UTR in ChiVMV-YunN/Yuxi was stable when transmitted through three generations. Experiments with modified clones showed that the additional 15 nt are essential for infection by this isolate.

Theaflavin promoted apoptosis in nasopharyngeal carcinoma unexpectedly via inducing autophagy in vitro.

Objectives: This study aimed to investigate the mechanism of the anticancer effect of theaflavin (TF) in nasopharyngeal carcinoma. Materials and Methods: CNE2 cells were used to study the anticancer effect of TF. This study used Cell Counting Kit-8 (CCK8) assay on proliferation and used flow cytometry to detect apoptosis. The protein expression of Bcl-2, Bax, caspase 3, and caspase 9 was detected by Western blot, and autophagy-related proteins were also detected. Results: TF inhibited proliferation of CNE2 cells, promoted apoptosis, and up-regulated the expression of caspase 3, caspase 9, and Bax, and decreased the level of Bcl-2. Unexpectedly, TF induced autophagy rather than inhibiting autophagy through up-regulating the levels of the autophagy marker light chain 3 (LC3) and Lysosomal-associated membrane protein 1 (LAMP1) and reducing levels of the autophagosome cargo protein p62, and the effect was via the mTOR pathway. Besides, autophagy inhibitor Chloroquine (CQ) suppressed the effect of TF on Bax, Bcl-2 and activation of caspase 3 and caspase 9. Conclusion: TF promoted apoptosis of nasopharyngeal carcinoma cells, the mechanism was unexpectedly involved in inducing autophagy.

Biological and Genetic Characterization of Pod Pepper Vein Yellows Virus-Associated RNA From Capsicum frutescens in Wenshan, China.

Tombusvirus-like associated RNAs (tlaRNAs) are positive-sense single-stranded RNAs found in plants co-infected with some viruses of the genus Polerovirus. Pod pepper vein yellows virus (PoPeVYV) was recently reported as a new recombinant polerovirus causing interveinal yellowing, stunting, and leaf rolling in Capsicum frutescens plants at Wenshan city, Yunnan province, China. The complete genome sequence of its associated RNA has now been determined by next-generation sequencing and reverse transcription (RT) polymerase chain reaction (PCR). PoPeVYV-associated RNA (PoPeVYVaRNA) (GenBank Accession No. MW323470) has 2970 nucleotides and is closely related to other group II tlaRNAs, particularly tobacco bushy top disease-associated RNA (TBTDaRNA, GenBank Accession No. EF529625). In infection experiments on Nicotiana benthamiana and C. frutescens plants, synergism between PoPeVYVaRNA and PoPeVYV was demonstrated, leading to severe interveinal yellowing of leaves and stunting of plants. The results provide further information on the genetic and biological properties of the various agents associated with pepper vein yellows disease (PeVYD).

Second-look endoscopy-guided therapy under sedation prevents early rebleeding after variceal ligation for acute variceal bleeding.

OBJECTIVES: To investigate whether second-look endoscopy (SLE)-guided therapy could be used to prevent post-endoscopic variceal ligation (EVL) early bleeding. METHODS: Consecutive cirrhotic patients with large esophageal varices (EV) receiving successful EVL for acute variceal bleeding (AVB) or secondary prophylaxis were enrolled. The patients were randomized into a SLE group and a non-SLE group (NSLE) 10 days after EVL. Additional endoscopic interventions as well as proton pump inhibitors and octreotide administration were applied based on the SLE findings. The post-EVL early rebleeding and mortality rates were compared between the two groups. RESULTS: A total of 252 patients were included in the final analysis. Post-EVL early rebleeding (13.5% vs 4.8%, P = 0.016) and bleeding-caused mortality (4.8% vs 0%, P = 0.013) were more frequently observed in the NSLE group than in the SLE group. However, post-EVL early rebleeding and mortality rates were reduced by SLE in patients receiving EVL for AVB only but not in those receiving secondary prophylaxis. Patients with Child-Pugh classification B to C at randomization (hazard ratio [HR] 8.77, P = 0.034), AVB at index EVL (HR 3.62, P = 0.003), discontinuation of non-selective ß-blocker after randomization (HR 4.68, P = 0.001) and non-SLE (HR 2.63, P = 0.046) were more likely to have post-EVL early rebleeding. No serious adverse events occurred during SLE. CONCLUSION: SLE-guided therapy reduces post-EVL early rebleeding and mortality rates in cirrhotic patients with large EV receiving EVL for AVB.

Cap-Assisted Endoscopic Sclerotherapy vs Ligation in the Long-Term Management of Medium Esophageal Varices: A Randomized Trial.

INTRODUCTION: Compared with endoscopic variceal ligation (EVL), cap-assisted endoscopic sclerotherapy (CAES) improves efficacy in the treatment of small esophageal varices (EVs) but has not been evaluated in the management of medium EVs. The aim of this study was to compare CAES with EVL in the long-term management of patients exhibiting cirrhosis with medium EVs and a history of esophageal variceal bleeding (EVB), with respect to variceal eradication and recurrence, adverse events, rebleeding, and survival. METHODS: Cirrhotic patients with medium EVs and a history of EVB were divided randomly into EVL and CAES groups. EVL or CAES was repeated each month until variceal eradication. Lauromacrogol was used as a sclerosant. Patients were followed up until 1 year after eradication. RESULTS: In total, 240 patients (age: 51.1 ± 10.0 years; men: 70.8%) were included and randomized to the EVL and CAES groups. The recurrence rate of EVs was much lower in the CAES group than in the EVL group (13.0% vs 30.7%, P = 0.001). The predictors for variceal recurrence were eradication by EVL (hazard ratio [HR]: 2.37, P = 0.04), achievement of complete eradication (HR: 0.27, P < 0.001), and nonselective ß-blocker response (HR: 0.32, P = 0.003). There was no significant difference in the rates of eradication, rebleeding, requirement for alternative therapy, and mortality or the incidence of complications between groups. DISCUSSION: CAES reduces the recurrence rate of EVs with comparable safety to that of EVL in the long-term management of patients presenting cirrhosis with medium EVs and a history of EVB.

Autophagy inhibition enhanced 5­FU­induced cell death in human gastric carcinoma BGC­823 cells.

The exact molecular mechanism of 5-fluorouracil (5-FU) in human gastric cancer cells remains to be elucidated. Cultured BGC­823 human gastric carcinoma and AGS cell lines were treated with 5­FU. Autophagosome formation was investigated through multiple approaches, including the quantification of green fluorescent protein­microtubule­associated protein 1A/1B­light chain 3 (LC3) puncta, LC3 conversion and electron microscopy observations. Additionally, autophagy was inhibited using 3­methyladenine (3­MA) and beclin­1 ablation, to determine its role in 5­FU­mediated cell death. In addition, the present study assessed alterations in sirtuin expression following 5­FU treatment with reverse transcription­quantitative polymerase chain reaction. 5­FU treatment induced apoptosis and inhibited proliferation in BGC­823 and AGS gastric cancer cells. It is of note that the 5­FU treatment only promoted autophagy in BGC­823 cells. Additionally, inhibition of autophagy by either 3­MA or beclin­1 ablation increased 5­FU­induced cell death in BGC­823 cells. The present study quantified changes in sirtuin (SIRT1, SIRT3, SIRT5, and SIRT6) expression following 5­FU treatment and using a specific inhibitor, sirtinol, the present study investigated their involvement in 5­FU­mediated autophagy. Autophagy inhibition through manipulation of sirtuin proteins may increase the therapeutic efficacy of the 5­FU chemotherapeutic drug against gastric carcinoma.

Duodenal variceal bleeding secondary to idiopathic portal hypertension treated with transjugular intra-hepatic porto-systemic shunt plus embolization: A case report.

BACKGROUND: Duodenal varices are a lesser-known complication with non-cirrhotic portal hypertension. We report a circuitous route from missed diagnosis of duodenal varices to correction. An extremely rare case of duodenal variceal bleeding secondary to idiopathic portal hypertension (IPH) is expounded in this study, which was controlled by transjugular intra-hepatic porto-systemic shunt (TIPS) plus embolization. CASE SUMMARY: A 46-year-old woman with anemia for two years was frequently admitted to the local hospital. Upon examination, anemia was attributed to gastrointestinal tract bleeding, which resulted from duodenal variceal bleeding detected by repeated esophagogastroduodenoscopy. At the end of a complete workup, IPH leading to duodenal varices was diagnosed. Portal venography revealed that the remarked duodenal varices originated from the proximal superior mesenteric vein. TIPS plus embolization with coils and Histoacryl was performed to obliterate the rupture of duodenal varices. The anemia resolved, and the duodenal varices completely vanished by 2 mo after the initial operation. CONCLUSION: TIPS plus embolization may be more appropriate to treat the bleeding of large duodenal varices.

Senescence-associated Long Non-coding RNA (SALNR) Delays Oncogene-induced Senescence through NF90 Regulation.

Long non-coding RNAs (lncRNAs) have recently emerged as key players in many physiologic and pathologic processes. Although many lncRNAs have been identified, few lncRNAs have been characterized functionally in aging. In this study, we used human fibroblast cells to investigate genome-wide lncRNA expression during cellular senescence. We identified 968 down-regulated lncRNAs and 899 up-regulated lncRNAs in senescent cells compared with young cells. Among these lncRNAs, we characterized a senescence-associated lncRNA (SALNR), whose expression was reduced during cellular senescence and in premalignant colon adenomas. Overexpression of SALNR delayed cellular senescence in fibroblast cells. Furthermore, we found that SALNR interacts with NF90 (nuclear factor of activated T-cells, 90 kDa), an RNA-binding protein suppressing miRNA biogenesis. We demonstrated that NF90 is a SALNR downstream target, whose inhibition led to premature senescence and enhanced expressions of senescence-associated miRNAs. Moreover, our data showed that Ras-induced stress promotes NF90 nucleolus translocation and suppresses its ability to suppress senescence-associated miRNA biogenesis, which could be rescued by SALNR overexpression. These data suggest that lncRNA SALNR modulates cellular senescence at least partly through changing NF90 activity.

Lutein prevents alcohol-induced liver disease in rats by modulating oxidative stress and inflammation.

OBJECTIVE: Oxidative stress and inflammation play an important role in pathogenesis of alcohol-induced liver injury. The present study was designed to investigate the protective role of Lutein against alcohol-induced liver injury. TREATMENT: Wistar rats weighing 150-200 g were divided into 3 groups, control, EtOH treatment, Lutein followed by EtOH treatment. Ethanol-treated rats received EtOH [5 g/kg body weight] by gavage every 12 hours for a total of 3 doses. For Lutein pre-treatment, Lutein at a dose of 40 mg/kg was dissolved in the EtOH and gavaged 30 mins before EtOH treatment. METHODS: Oxidative stress markers-(reactive oxygen species, lipid peroxidation, protein carbonyls and sulfhydryls content), liver markers (ALT, AST, ALP and LDH) were determined. Antioxidant enzyme activities and its master regulator Nrf-2 expression were analyzed. Further, inflammatory proteins NF-κB, COX-2, iNOS and inflammatory cytokines (TNF-α, MCP-1, IL-1ß, IL-6) were analyzed. RESULTS: The results showed significant decrease in oxidative stress markers and liver markers in the lutein pre-treatment. Lutein treatment down regulated inflammatory proteins and cytokines with concomitant up regulation in Nrf-2 levels and antioxidant enzymic activities. CONCLUSION: The present study showed that Lutein treatment exerted potent antioxidant and anti-inflammatory property and offered significant cytoprotection against alcohol-induced liver injury.

Caspase-3 expression in metastatic lymph nodes of esophageal squamous cell carcinoma is prognostic of survival.

AIM: To assess whether differential expression of caspase-3 in paired metastatic lymph nodes (LNs) is prognostic of survival in patients with resectable esophageal squamous cell carcinoma (ESCC). METHODS: Capases-3 expression was evaluated immunohistochemically in 122 pairs of primary ESCCs and regional metastatic LNs assembled on tissue microarrays. The impact of caspase-3 expression on survival outcomes was analyzed by the Kaplan-Meier method and Cox proportional hazards regression model. RESULTS: The level of caspase-3 expression was significantly higher in LN metastases than in primary tumors (P < 0.001). Caspase-3 expression in the primary tumors was associated with longer median survival (23 mo vs 21 mo, P = 0.033), whereas higher expression in paired metastatic LNs was associated with shorter median survival (20 mo vs 22 mo, P = 0.043). Multivariate analysis showed that both were independent prognostic factors. CONCLUSION: Caspase-3 expression in metastatic LNs may be a potential independent predictor of poorer overall survival in patients with resected ESCC and LN metastasis. Protein expression in metastatic tumors may be a biomarker prognostic of survival.

Involvement of ß-catenin in matrine-induced autophagy and apoptosis in WB-F344 cells.

Matrine, one of the main components extracted from Sophora flavescens, has exhibited pharmacological effects on the differentiation in rat liver oval cells. However, its function and mechanism have not yet been fully elucidated. To further investigate them, an in vitro model was established using a rat liver oval cell line called WB-F344 and treated with matrine. Initially, a significant increase in the number of monodansylcadaverine-positive cells and in the levels of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, which is a specific marker for detecting autophagy, was observed in matrine-treated cells. This indicated that autophagy was stimulated by matrine, which was further confirmed by transmission electron microscopy. Additionally, the apoptotic oval cells were easily detected under matrine treatment using an Annexin-V-fluorescein isothiocyanate/propidium iodide assay, indicating that autophagy and apoptosis were synchronously induced by matrine. A decrease in B-cell lymphoma (Bcl-2) mRNA expression, but an increase in Bcl2-associated X protein (Bax) mRNA expression were observed in matrine-treated cells, which led to an upregulation of the Bax/Bcl-2 ratio, a molecular marker for determining the extent of apoptosis. Next, the molecular mechanism of matrine-induced autophagy and apoptosis was analyzed in WB-F344 cells. ß-catenin degradation was downregulated by matrine and rapamycin, a foregone chemical agonist of autophagy, whereas it was upregulated by 3-methyladenine, a specific inhibitor of autophagy. Additionally, ß-catenin activation induced an increase in LC3-II levels and reversed the Bax/Bcl-2 mRNA ratio under matrine treatment, whereas inhibition of ß-catenin by RNA interference induced a decrease of the LC3-II amount and of the Bax/Bcl-2 mRNA ratio. Finally, matrine treatment attenuated p53; however, with little or no change in LC3-II levels, but a decrease in ß-catenin levels occurred in WB-F344 cells upon treatment with pifithrin-α, a chemical inhibitor of p53, revealing that p53, interfering with ß-catenin, may not be involved in matrine-induced autophagy in WB-F344 cells. These results demonstrate that ß-catenin is involved in matrine-induced autophagy and apoptosis in WB-F344 cells, while ß-catenin is negatively regulated by autophagy and positively by p53, indicating that ß-catenin may be involved in the crosstalk between autophagy and apoptosis in WB-F344 cells.

CSTP1, a novel protein phosphatase, blocks cell cycle, promotes cell apoptosis, and suppresses tumor growth of bladder cancer by directly dephosphorylating Akt at Ser473 site.

Akt/protein kinase B is a pivotal component downstream of phosphatidylinositol 3-kinase (PI3K) pathway, whose activity regulates the balance between cell survival and apoptosis. Phosphorylation of Akt occurs at two key sites either at Thr308 site in the activation loop or at Ser473 site in the hydrophobic motif. The phosphorylated form of Akt (pAkt) is activated to promote cell survival. The mechanisms of pAkt dephosphorylation and how the signal transduction of Akt pathway is terminated are still largely unknown. In this study, we identified a novel protein phosphatase CSTP1(complete s transactivated protein 1), which interacts and dephosphorylates Akt specifically at Ser473 site in vivo and in vitro, blocks cell cycle progression and promotes cell apoptosis. The effects of CSTP1 on cell survival and cell cycle were abrogated by depletion of phosphatase domain of CSTP1 or by expression of a constitutively active form of Akt (S473D), suggesting Ser473 site of Akt as a primary cellular target of CSTP1. Expression profile analysis showed that CSTP1 expression is selectively down-regulated in non-invasive bladder cancer tissues and over-expression of CSTP1 suppressed the size of tumors in nude mice. Kaplan-Meier curves revealed that decreased expression of CSTP1 implicated significantly reduced recurrence-free survival in patients suffered from non-invasive bladder cancers.

Nifedipine induced autophagy through Beclin1 and mTOR pathway in endometrial carcinoma cells.

BACKGROUND: Endometrial carcinoma is one of the most common female tract genital malignant tumors. Nifedipine, an L-type calcium channel antagonist can inhibit cell proliferation of carcinomas. Recent studies indicated that a rise in the free cytosolic calcium ([Ca(2+)](c)) was a potent inducer of autophagy. Here, we investigated the relationship between nifedipine and autophagy in Hec-1A cells. METHODS: Cells were cultured with nifedipine (10 µmol/L) and harvested at different times for counting cell number. MTT assay was applied to evaluate the cell viability and transwell assay to reveal cell migration. Apoptotic cells were detected with annexin V/PI assay. Then cells were treated with 3-methyladenine (3-MA) (2.5 mmol/L) for 0, 5, 15, 30, 60, and 120 minutes and the expression of the L-type calcium channel alpha1D (Cav1.3) protein was detected. At last, cells were cultured and assigned to four groups with different treatment: untreated (control group), 10 µmol/L nifedipine (N group), 2.5 mmol/L 3-MA (3-MA group), and 10 µmol/L nifedipine plus 2.5 mmol/L 3-MA (N+3MA group). Autophagy was detected with GFP-LC3 modulation by fluorescent microscopy, and expression of the autophagy-associated proteins (LC3, Beclin1 and P70s6K) by Western blotting and monodansylcadaverine (MDC) labeled visualization. RESULTS: Proliferation of Hec-1A cells was obviously suppressed by nifedipine compared with that of the untreated cells for 24, 48, and 96 hours (P = 0.000 for each day). The suppression of migration ability of the nifedipine-treated cells (94.0 ± 8.2) was significantly different from that of the untreated cells (160.00 ± 9.50, P = 0.021). The level of early period cell apoptosis induced by nifedipine was (2.21 ± 0.19)%, which was (2.90 ± 0.13)% in control group (P = 0.052), whereas the late period apoptosis level reached (10.38 ± 0.96)% and (4.40 ± 0.60)% (P = 0.020), respectively. The 3-MA group induced a slight increase in the Cav1.3 levels within 15 minutes, but significantly attenuated the Cav1.3 levels after 30 minutes. There were more autophagic vacuoles labeled by MDC in the N group (20.63 ± 3.36) than the control group (6.29 ± 0.16, P = 0.015). GFP-LC3 localization revealed that the LC3 levels of cells in 3-MA group, N+3MA group, 3-MA group were 2.80 ± 0.29, 2.30 ± 0.17, and 1.80 ± 0.21, respectively. Cells in the N group showed significant augmentation of autophagy (P < 0.05). Western blotting analysis confirmed the down-regulation of LC3 levels in 3-MA group (0.85 ± 0.21) and N+3MA group (1.21 ± 0.12) compared with nifedipine treatment (2.64 ± 0.15, P < 0.05). The annexin-V-FITC/PI assay showed that the level of early period cell apoptosis induced in the N+3-MA group ((11.22 ± 0.91)%) differed significantly from that of the control group ((2.51 ± 0.70)%) and N group ((3.47 ± 0.39)%). Similarly, the late period level of the N+3-MA group ((55.19 ± 2.51)%) differed significantly from that of the control group ((15.81 ± 1.36)%) and the N group ((22.09 ± 2.48)%, P < 0.05). The down-regulated expression of P70s6k and up-regulated expression of the Beclin1 revealed significant differences between the N+3-MA group and control group (P = 0.025; Beclin1: P = 0.015). CONCLUSIONS: Proliferation and migration in vitro of endometrial carcinoma Hec-1A cells are significantly suppressed by nifedipine. The nifedipine leads autophagy to oppose Hec-1A cells apoptosis. Autophagy inhibition by 3-MA leads down-regulation of Cav1.3 and enhances nifedipine-induced cell death. The nifedipine-induced autophagy is linked to Beclin1 and mTOR pathways.

Autophagy inhibition enhances etoposide-induced cell death in human hepatoma G2 cells.

Induction of autophagy usually acts as a survival mechanism of cancer cells in response to chemotherapy. However, the function and molecular mechanism of autophagy in human hepatoma cells under drug treatment is still not clear. To address this issue, we established an experimental model in which HepG2 cells were treated with etoposide, a widely used anticancer agent. We demonstrate the etoposide-induced accumulation of GFP-LC3 dots by fluorescent microscopy, the up-regulation of LC3-II protein expression by Western blotting and the increased number of autophagic vacuoles by electron microscopy, confirming the activation of autophagy by etoposide in HepG2 cells. Inhibition of autophagy by either 3-methyladenine (3MA) or beclin-1 small interfering RNA enhanced etoposide-induced cell death. Furthermore, activation of p53 and AMPK was detected in etoposide-treated cells and inhibition of AMPK triggered apoptosis through suppression of autophagy. On the other hand, inactivation of p53 promoted cell survival through augmentation of autophagy. Collectively, these findings indicate that etoposide-induced autophagy promotes hepatoma cell adaptation and survival, and that autophagy inhibition improves the chemotherapeutic effect of etoposide. Moreover, AMPK activation is clearly associated with etoposide-induced autophagy. We conclude that manipulation of AMPK may be a promising approach of adjuvant chemotherapy for hepatocellular carcinoma.

[Effect of baicalin on liver fatty acid binding protein in oxidative stress model in vitro].

OBJECTIVE: To investigate the effect of baicalin on liver fatty acid binding protein in oxidative stress model in vitro. METHODS: (1) Cellular oxidative stress in vitro was induced by incubating cells with 400µmol/L hydrogen peroxide (H2O2) for 20 minutes at 37 degrees C in the dark. After Chang liver cell line was treated with different dose of baicalin for 24, 48 and 72 hours. MTT assay was employed to detect cell viability, and then the hydrogen peroxide (TC50) of the different dose of baicalin was calculated. (2) Based on MTT assay, cells were treated with three different doses of baicalin (25, 50, 100 µmol/L) for 24 and 48 hours before being exposed to 400 µmol/L H2O2 for 20 minutes at 37 degrees C. Then, reactive oxygen species (ROS) assay and activity assays of superoxide dismutase (SOD) and reduced glutathione hormone (GSH) were evaluated. (3) Realtime PCR and Western blotting were applied to explore the influence of baicalin on the expression level of L-FABP. (4) One-way ANOVA was used for results statistical analysis. RESULT: (1) MTT assay showed baicalin treatment at 25, 50, 100 µmol/L for 24 and 48 hours was feasible (83.60% ± 3.47%, 72.36% ± 2.18%, 70.16% ± 2.04% for 24 hours; 84.93% ± 3.11%, 76.16% ± 2.45%, 72.72% ± 2.31% for 48 hours, P > 0.05, F = 386.24, 475.92 respectively). Meanwhile, we found by the linear regression model that the median toxic concentration of baicalin for 48 hours was 170.6 µmol/L, and the median toxic concentration of baicalin for 24 hours was 153.2 µmol/L. (2) ROS assay showed dichlorofluorescin in all baicalin-treated cells after stress was significantly reduced (37.0 ± 3.30, 22.90 ± 3.84, 29.60 ± 2.52 for 24 hours respectively, P < 0.05, F = 70.06; 35.77 ± 2.35, 21.80 ± 3.10, 23.87 ± 1.98 for 48 hours respectively, P < 0.05, F = 110.92) as compared with the H2O2-treated cells. Moreover, 50 µmol/L baicalin treatment for 48 hours was the optimal condition against ROS generation (21.80 ± 3.10, P < 0.01, F = 110.92). Furthermore, the activities of intracellular SOD and GSH was increased significantly (51.53 ± 1.91 µg/mg for SOD, P < 0.05, F = 93.81; 49.85 ± 1.45 U/mg for GSH, P < 0.05, F = 92.51). (3) Although realtime PCR analysis indicated 50 µmol/L baicalin treatment for 48 hours could have no changes of the level of L-FABP expression under the oxidative stress condition, western blotting analysis indicated 50 µmol/L baicalin treatment for 48 hours could increase up to about 80% for the level of L-FABP expression. CONCLUSION: Baicalin was suggested to be able to enhance both L-FABP expression and activity of intracellular SOD and GSH, and therefore protected hepatocytes from oxidative stress.

Separation and characterization of clindamycin phosphate and related impurities in injection by liquid chromatography/electrospray ionization mass spectrometry.

A simple high-performance liquid chromatography/electrospray ionization tandem mass spectrometric (HPLC/ESI-MS/MS) method has been developed for the rapid identification of clindamycin phosphate and its degradation products or related impurities in clindamycin phosphate injection. Detection was performed by quadrupole time-of-flight mass spectrometry (Q-TOFMS) via an ESI source in positive mode. Clindamycin phosphate and its related substances lincomycin, 7-epilincomycin-2-phosphate, lincomycin-2-phosphate, clindamycin B, clindamycin B-2-phosphate, and clindamycin were identified simultaneously by HPLC/ESI-MS/MS results. Based on the MS/MS spectra of their quasi-molecular ions, the fragmentation pathways of clindamycin phosphate and its related substances were compared and proposed, which are specific and useful for the identification of the lincosamide antibiotics and related impurities. The method was rapid, sensitive and specific and can be used to identify clindamycin phosphate and its related impurities in clindamycin phosphate injection without control compounds.

Separation and identification of purine nucleosides in the urine of patients with malignant cancer by reverse phase liquid chromatography/electrospray tandem mass spectrometry.

Urinary-modified nucleosides have a potential role as cancer biomarkers for a number of malignant diseases. High performance liquid chromatography (HPLC) was combined with full-scan mass spectrometry, MS/MS analysis and accurate mass measurements in order to identify purine nucleosides purified from urine. Potential purine nucleosides were assessed by their evident UV absorbance in the HPLC chromatogram and then further examined by the mass spectrometric techniques. In this manner, numerous modified purine nucleosides were identified in the urine samples from cancer patients including xanthine, adenosine, N1-methyladenosine, 5'-deoxy-5'-methylthioadenosine, 2-methyladenosine, N6-threonylcarbamoyladenosine, inosine, N1-methylinosine, guanosine, N1-methylguanosine, N7-methylguanine, N2-methylguanosine, N2,N2-dimethyguanosine, N2,N2,N7-trimethylguanosine. Furthermore, a number of novel purine nucleosides were tentatively identified via critical interpretation of the combined mass spectrometric data including N3-methyladenosine, N7-methyladenine, 5'-dehydro-2'-deoxyinosine, N3-methylguanine, O6-methylguanosine, N1,N2,N7-trimethylguanosine, N1-methyl-N2-ethylguanosine and N7-methyl-N1-ethylguanosine.

Analysis of modified nucleosides in the urine of patients with malignant cancer by liquid chromatography/electrospray ionization mass spectrometry.

As modified nucleosides reflect altered tRNA turnover which seems to be impaired in the body of cancer patients, they have been evaluated as potential tumor markers. High-performance liquid chromatography/electrosprary ionization quadrupole time-of-flight mass spectrometry (HPLC/ESI-Q-TOFMS) was used to identify nucleosides purified from urine in positive ionization mode. Potential nucleosides were assessed by their evident UV absorbance in HPLC and then further examined by mass spectrometric techniques. In this manner, 21 nucleosides were detected in the urine of a patient with lymphoid cancer including three modified nucleosides 5'-dehydro-2-deoxyinosine, N1,N2,N7-trimethylguanosine and N1-methyl-N2-ethylguanosine, which had never been reported previously.