Quercetin from Polygonum capitatum Protects against Gastric Inflammation and Apoptosis Associated with Helicobacter pylori Infection by Affecting the Levels of p38MAPK, BCL-2 and BAX

A one-step non-radioactive assay to determine the proliferation of murine lymphocytes, lymphoid tumor cells and hybridoma cells is described. This assay requires the addition of Alamar Blue dye to cell cultures and the degree of change in its color, which is reflective of the extent of cellular proliferation, can be determined by an ELISA plate reader. Alamar Blue must be added during the initial phase of cell culture. The pattern of concanavalin A (ConA) or anti-CD3 antibody-induced proliferative response of murine lymphocytes as assessed by Alamar Blue was similar to that of a [3H]thymidine assay. Similarly, the spontaneous proliferation curve of anti-CD3 antibody secreting cell line (YCD3-1), monocytic macrophage cell lines (PU5-1.8, P388D1, J774.1) and myeloma cells (Sp2/0) as determined by Alamar Blue closely resembled that of the [3H]thymidine assay. The minimum detectable number of proliferating cells was comparable in Alamar Blue and [3H]thymidine assays. Since cell lysis/extraction and washing procedures are not involved in the Alamar Blue assay, this approach has several distinct advantages over currently available assays (eg. [3H]thymidine). First, it allows daily monitoring of proliferation without compromising the sterility of cultures. An indication of proliferation can be evaluated (spectrophotometrically or visually) as early as 24 h after ConA stimulation. Second, unlike previously reported assays, Alamar Blue permits further analysis of proliferating cells by other methods. Analysis of cells in culture with Alamar Blue for various surface antigens (CD44, CD45RB, CD4, heat stable antigen) by flow cytometry revealed that the fluorescent profile and relative percentage of cells in cultures with the Alamar Blue were comparable to those without this reagent. The salient advantages of Alamar Blue assay over the [3H]thymidine assay include: (i) non-radioactivity; (ii) simplicity; (iii) less costly; (iv) non-labor intensive; (v) rapidity of assessment of proliferation of large number of samples; (vi) non-toxicity; (vii) usefulness in determining the kinetics of cell growth of hybridomas; and (viii) non-interference of secretion of antibodies by a hybridoma cell line.

To review previous studies (the last 6 years) about the Helicobacter pylori (H. pylori) antibiotic resistance in order to evaluate the trend in antibiotic resistance.

Many viruses interact with the host cell division cycle to favor their own growth. In this study, we examined the ability of influenza A virus to manipulate cell cycle progression. Our results show that influenza A virus A/WSN/33 (H1N1) replication results in G(0)/G(1)-phase accumulation of infected cells and that this accumulation is caused by the prevention of cell cycle entry from G(0)/G(1) phase into S phase. Consistent with the G(0)/G(1)-phase accumulation, the amount of hyperphosphorylated retinoblastoma protein, a necessary active form for cell cycle progression through late G(1) into S phase, decreased after infection with A/WSN/33 (H1N1) virus. In addition, other key molecules in the regulation of the cell cycle, such as p21, cyclin E, and cyclin D1, were also changed and showed a pattern of G(0)/G(1)-phase cell cycle arrest. It is interesting that increased viral protein expression and progeny virus production in cells synchronized in the G(0)/G(1) phase were observed compared to those in either unsynchronized cells or cells synchronized in the G(2)/M phase. G(0)/G(1)-phase cell cycle arrest is likely a common strategy, since the effect was also observed in other strains, such as H3N2, H9N2, PR8 H1N1, and pandemic swine H1N1 viruses. These findings, in all, suggest that influenza A virus may provide favorable conditions for viral protein accumulation and virus production by inducing a G(0)/G(1)-phase cell cycle arrest in infected cells.