A prospective, multicenter, clinical study of duodenoscope contamination after reprocessing.

OBJECTIVE: Several clinical procedures utilize duodenoscopes, which are processed for reuse after the procedures are completed. However, infection outbreaks due to improper duodenoscope processing occur frequently. To address this, we aimed to assess the contamination rates of duodenoscopes after reprocessing in nonoutbreak settings. DESIGN AND SETTING: Prospective study in 16 clinical sites in the United States. METHODS: We sampled and cultured reprocessed duodenoscopes following the FDA/CDC/ASM guideline; "Duodenoscope Surveillance Sampling and Culturing - Reducing the Risks of Infection." High-concern (HC) organisms were those highly associated with disease, including gram-negative rods, Staphylococcus aureus, Staphylococcus lugdunensis, ß-hemolytic Streptococcus, Enterococcus spp, and yeasts. We evaluated duodenoscopes with ≥1 CFU of organisms after reprocessing. The reprocessing environments were also sampled and cultured. RESULTS: We assessed 859 newer-model (NM) duodenoscopes (TJF-Q180V) and 850 older-model (OM) duodenoscopes (TJF-160F/VF); of these, 35 NM samples (4.1%) and 56 OM samples (6.6%) were contaminated with HC organisms. We detected and classified the HC organisms as gastrointestinal (45.4%), human origin (16.7%), environmental (24.1%), waterborne (13.0%), and unidentified (0.9%). CONCLUSIONS: We detected an overall HC contamination rate of 5.3% in nonoutbreak settings. Although the relationship between endoscopic contamination and the occurrence of infections remains unclear, attempts should continue to be made to further reduce contamination rates. Additional improvements to the manufacturer's instructions for use, human factors during the reprocessing procedure, ongoing training programs, cleanliness of reprocessing environments, and the design of the distal end of the duodenoscope should be considered.

Molecular imaging of aberrant crypt foci in the human colon targeting glutathione S-transferase P1-1.

Aberrant crypt foci (ACF), the earliest precursor lesion of colorectal cancers (CRCs), are a good surrogate marker for CRC risk stratification and chemoprevention. However, the conventional ACF detection method with dye-spraying by magnifying colonoscopy is labor- and skill-intensive. We sought to identify rat and human ACF using a fluorescent imaging technique that targets a molecule specific for ACF. We found that glutathione S-transferase (GST) P1-1 was overexpressed in ACF tissues in a screening experiment. We then synthesized the fluorogenic probe, DNAT-Me, which is fluorescently quenched but is activated by GSTP1-1. A CRC cell line incubated with DNAT-Me showed strong fluorescence in the cytosol. Fluorescence intensities correlated significantly with GST activities in cancer cell lines. When we sprayed DNAT-Me onto colorectal mucosa excised from azoxymethane-treated rats and surgically resected from CRC patients, ACF with strong fluorescent signals were clearly observed. The ACF number determined by postoperative DNAT-Me imaging was almost identical to that determined by preoperative methylene blue staining. The signal-to-noise ratio for ACF in DNAT-Me images was significantly higher than that in methylene blue staining. Thus, we sensitively visualized ACF on rat and human colorectal mucosa by using a GST-activated fluorogenic probe without dye-spraying and magnifying colonoscopy.

Fasting induced up-regulation of activating transcription factor 5 in mouse liver.

AIMS: Food deprivation (fasting) is commonly encountered in the lives of animals and humans. In mammals, adaptive responses predominantly include the induction of hepatic gluconeogenesis, but the regulatory mechanisms remain unclear. Atf5 (activating transcription factor 5) is a transcription factor of the ATF/cAMP response element-binding protein family and is expressed abundantly in human liver. Atf5 has been associated with stress responses, cell differentiation, proliferation, and survival. However, its role in the liver response to in vivo food deprivation has not yet been investigated. MAIN METHODS: Adult mice were food-deprived for 48 h and the expression of two Atf5 mRNA subtypes (Atf5-R1 and Atf-R2) and gluconeogenic factors was investigated. Using in vitro cell culture, Pgc-1alpha (peroxisome proliferator-activated receptor-gamma coactivator-1alpha) promoter activities after ectopic expression of Atf5 and Cebpg (CCAAT/enhancer-binding protein gamma) proteins were measured. KEY FINDINGS: The Atf5-R1 transcript was found to be abundant in liver and other energy metabolism-related organs; Atf5-R2 was prominent in the testis. Fasting resulted in elevation of the expression of both Atf5-R1 and R2 in the liver. Interestingly, up-regulation of Atf5 was accompanied by increased expression of Cebpg and Pgc-1alpha. In human hepatoma cells (HepG2), but not in human cervical carcinoma cells (HeLa), forced expression of Atf5 and Cebpg cooperatively stimulated Pgc-1alpha promoter activity, suggesting that hepatic Pgc-1alpha could be induced by Atf5 and Cebpg in cooperation with other hepatic factors. SIGNIFICANCE: Hepatic Atf5 might be potentially involved in the induction of gluconeogenetic factors during in vivo fasting stress.

Identification of peroxisome-proliferator responsive element in the mouse HSL gene.

Hormone-sensitive lipase (HSL) catalyzes the rate-limiting step of lipolysis in adipose tissue. Several studies suggest that protein phosphorylation regulates the HSL enzymatic activity. On the other hand, the precise mechanism of the transcriptional regulation of the HSL gene remains to be elucidated. Here, we identified a functional peroxisome-proliferator responsive element (PPRE) in the mouse HSL promoter by reporter assay in CV-1 cells using serial deletion and point mutants of the 5'-flanking region. Chromatin immunoprecipitation (ChIP) analysis revealed that both peroxisome-proliferator activated receptor (PPARgamma) and retinoid X receptor (RXRalpha) interacted with the region. Binding of the PPARgamma/RXRalpha heterodimer to the PPRE sequence was also confirmed by electrophoretic mobility shift assay. These results indicate that the HSL gene is transcriptionally regulated by PPARgamma/RXRalpha heterodimer, and suggest that a cis-acting element regulates the HSL gene expression.

Prolonged hypoxia accelerates the posttranscriptional process of collagen synthesis in cultured fibroblasts.

Molecular oxygen is essential for metazoan life. Hypoxia, a reduced oxygen condition, induces systemic and cellular responses for acclimation to the limited oxygen availability. Multicellularity of metazoans is maintained on extracellular matrices. Previously, we demonstrated that acute hypoxia up-regulated the prolyl 4-hydroxylase alpha(I) subunit, the rate-limiting subunit for the hydroxylation of proline residues of procollagens (Y. Takahashi, S. Takahashi, Y. Shiga, T. Yoshimi, and T Miura, 2000, J. Biol. Chem., 275, 14139-14146). The formation of hydroxyproline is an essential posttranscriptional process for stabilization of the helical trimer of procollagen polypeptides at physiological temperature. In this present study, we cultured fetal rat lung fibroblasts for up to 9 days and examined the effects of prolonged hypoxia on the level of procollagen mRNA in the cells and the posttranscriptional steps of collagen synthesis. Hypoxia accelerated the deposition of collagen molecules. These enhancements in hypoxic cultures were observed with or without ascorbic acid in the culture medium. The steady-state level of procollagen alpha1(I) mRNA was not affected by the prolonged hypoxia. In contrast, the mRNA and protein levels of the prolyl 4-hydroxylase alpha(I) subunit were increased by hypoxic culture under both ascorbic acid-sufficient and -deficient conditions. These results suggest that hypoxic enhancement of the posttranscriptional step of collagen synthesis contributed to the accelerated deposition of collagen fibrils.