Characterization of methicillin-resistant Staphylococcus aureus isolated from retail raw chicken meat in Japan.

Two isolates of mecA-positive methicillin-resistant Staphylococcus aureus (MRSA) from retail raw chicken meat were characterized by phenotypic and genotypic methods. One isolate showed the human biovar, coagulase type III, phage group I * III, the lack of production of enterotoxins and TSST-1, and resistance to PCG/ABPC/EM/GM/KM. The other isolate showed the human biovar, coagulase type III, phage group III, production of enterotoxin C and TSST-1, and resistance to PCG/ABPC/CEZ. The biotyping results indicate that the two isolates showed characteristics of human S. aureus. They also harbored SCCmec type IV, which has prevalently been found in community-acquired MRSA isolates. This paper is the first publication regarding MRSA isolates from raw chicken meat in Japan.

Lafutidine inhibits Helicobacter pylori-induced interleukin-8 production in human gastric epithelial cells.

BACKGROUND AND AIM: Attachment of Helicobacter pylori to gastric epithelial cells leads to the production of chemokines, such as interleukin-8 (IL-8), which in turn activate and recruit neutrophils to the site of infection. Lafutidine [(+/-)-2-(furfurylsulfinyl)-N-(4-(4-(piperidinomethyl)-2-pyridyl)oxy-(Z)-2-butenyl)acetamide] is a new type of antiulcer drug that possesses an antisecretory action as well as gastroprotective activity, independent of its antisecretory action. In the present study, we examined the effects of lafutidine on H. pylori-induced IL-8 release and H. pylori adhesion to MKN45 cells. METHODS: MKN45 cells were stimulated with H. pylori, tumor necrosis factor (TNF)-alpha, or IL-1beta, then IL-6 and IL-8 levels in the culture supernatants were determined with a specific enzyme-linked immunosorbent assay kit. RESULTS: Lafutidine significantly inhibited both the release of IL-8 induced by H. pylori and the adhesion of H. pylori to cells in a dose-dependent manner. These properties of lafutidine are unrelated to the blockade of histamine H(2)-receptors, because the same effects have not been observed with other H(2)-receptor antagonists, such as cimetidine and famotidine. Lafutidine also significantly inhibited H. pylori-induced IL-6 release. Both TNF-alpha and IL-1beta-induced IL-8 releases, conversely, were little affected by lafutidine up to a concentration of 10(-5) M. CONCLUSIONS: These results suggest that lafutidine inhibits IL-8 release by inhibiting H. pylori adherence to gastric epithelial cells, indicating a novel mechanism by which lafutidine protects against the mucosal inflammation associated with H. pylori infection.

Protein kinase C activation by Helicobacter pylori in human gastric epithelial cells limits interleukin-8 production through suppression of extracellular signal-regulated kinase.

Helicobacter pylori (H. pylori) infection of gastric epithelial cells has been shown to induce interleukin (IL)-8 production, but the signal transduction mechanism leading to IL-8 production has not been clearly defined. Here, we investigate the role of protein kinase C (PKC) in the mechanism of induction of IL-8 release by H. pylori in human gastric epithelial cells. In MKN45 cells, H. pylori-induced IL-8 release was enhanced by treatment with PKC inhibitors (GF109203X and calphostin C) and PKC depletion, which completely inhibited PKC activity. Moreover, PKC inhibitors and PKC depletion increased extracellular signal-regulated kinase (ERK) activity and phosphorylation, but not calcium/calmodulin-dependent protein kinase II (CaMK II) activity, in response to H. pylori infection. PKC activated by H. pylori inhibited activation of ERK induced by H. pylori without affecting the CaMK II activity and negatively regulated IL-8 production in human gastric epithelial cells.

Messenger RNA levels and enzyme activities of 5 alpha-reductase types 1 and 2 in human benign prostatic hyperplasia (BPH) tissue.

BACKGROUND: Benign prostatic hyperplasia (BPH) development requires testicular androgens and aging. The principle prostatic androgen is dihydrotestosterone (DHT). Testosterone is converted to DHT by the enzyme 5 alpha-reductase. Two distinct 5 alpha-reductase enzymes, types 1 and 2, have been identified. While some studies have suggested that type 2 isoenzyme predominates in the prostate, studies on the prostatic localization of the two isoenzymes are controversial. The purpose of this study was to determine the quantitative expressions of 5 alpha-reductase types 1 and 2 in BPH tissues. METHODS: We examined the localizations of types 1 and 2 isoenzymes in BPH tissues using immunohistochemical staining and a real-time quantitative RT-PCR assay using the TaqMan system. We measured the enzyme activities of types 1 and 2 at pH values of 7.5 and 5.0, respectively. RESULTS: Our immunohistochemical study showed that type 1 isoenzyme was expressed predominantly in epithelial cells, whereas type 2 isoenzyme was expressed in both stromal and epithelial cells. The real-time RT-PCR assay demonstrated that the copy numbers of type 1 isoenzyme mRNA were significantly higher than those of type 2 isoenzyme mRNA. There were significant associations between enzyme activity at pH 7.5 and type 1 isoenzyme mRNA expression, and between the activity at pH 5.0 and type 2 mRNA expressions. CONCLUSIONS: We demonstrated that 5 alpha-reductase type 1 had a specific enzyme activity in the prostate, which supports the hypothesis that the type 1 isoenzyme may play a significant role in maintaining prostate enlargement along with the type 2 isoenzyme.

Identification of a signaling cascade for interleukin-8 production by Helicobacter pylori in human gastric epithelial cells.

Infecting gastric epithelial cells with Helicobacter pylori (H. pylori) has been shown to induce interleukin-8 (IL-8) production, but the signal transduction mechanism leading to IL-8 production is not defined clearly. In the present study, we investigated the molecular mechanism responsible for H. pylori-induced IL-8 release in human gastric epithelial cells. IL-8 levels in culture supernatants were determined by an enzyme linked-immunosorbent assay. Extracellular signal-regulated kinase (ERK) activity was tested using an in vitro kinase assay, which measured the incorporation of [gamma-33P]ATP into a synthetic peptide that is a specific ERK substrate. ERK phosphorylation and IkappaBalpha degradation by H. pylori infection were assessed by western blotting. In MKN45 cells, H. pylori-induced IL-8 release in a time-dependent manner. This IL-8 release was abolished by treatment with intracellular Ca2+ chelators (BAPTA-AM and TMB-8) but not by EGTA or nifedipine. The Ca2+ ionophore A23187 also induced IL-8 release to an extent similar to that of H. pylori infection. Calmodulin inhibitors (W7 and calmidazolium) and tyrosine kinase inhibitors (genistein and ST638) completely blocked IL-8 release by H. pylori and A23187. PD98059, an ERK pathway inhibitor, completely abolished H. pylori-induced IL-8 release. Moreover, BAPTA-AM, calmidazolium, and genistein, but not nifedipine, suppressed the ERK activation induced by H. pylori infection. PD98059 as well as MG132, an NF-kappaB pathway inhibitor, blocked both IL-8 production and degradation of IkappaBalpha induced by H. pylori infection, whereas only PD98059 inhibited ERK activity in response to H. pylori. There was no significant difference between IL-8 production induced by the cagA positive wild-type strain and the cagA negative isogenic mutant strain of H. pylori; therefore, CagA is not involved in the IL-8 production pathway. H. pylori-induced IL-8 production is dominantly regulated by Ca2+/calmodulin signaling, and ERK plays an important role in signal transmission for the efficient activation of H. pylori-induced NF-kappaB activity, resulting in IL-8 production.