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GI flexible endoscope disinfection: "in use" test comparative study.

BACKGROUND/AIMS: There is some confusion as to the effectiveness of the available disinfectants for achieving "high level" disinfection, and the microbiologic method to assess the efficacy of the selected disinfectant regime. The "in use" method is adequate for control and for establishing comparisons between different disinfectants. METHODOLOGY: This study compares the efficacy of the different disinfectants and disinfection regimes available, including automatic systems to the 20-minute immersion in 20 degrees C 2%-alkaline-glutaraldehyde (AG). After cleaning and disinfection the effluent obtained from each channel was collected under sterile conditions. A total of 0.1 mL of the effluent was introduced in liquid thioglycolate, an additional 0.1 mL was seeded in solid blood agar and in MacConkey agar medium, and maintained for 48 hours at 37 degrees C. Thioglycolate media turbidity after a 48-hour culture indicates bacterial growth. RESULTS: The disinfectants used were 2% AG, 0.125% and 0.27% glutaraldehyde, glutaraldehydephenol-phenate, peracetic acid, N-duopropenida, 13%-H2O2-27%-lactic acid and ortho-phtalaldehyde using manual and automated methods. Most of the disinfectants available obtain similar or better results compared with 20' 2% AG. The best results (bacterial reduction greater than 3 log10), were those obtained using 20-minute 1/4 or 1/2 glutaraldehydephenol-phenate, 10-minute peracetic acid, or hydrogen-peroxide compounds, 5-minute 0.125% and 0.27% AG at high temperature and 5-minute 0.5% ortho-phtalaldehyde. CONCLUSIONS: A sensitive microbiologic method described may be useful in the control of disinfection and allowed: 1) knowledge of the limits of the efficacy of the disinfection methods usually used, 2) effective comparison of the different disinfectants and disinfection regimes and 3) awareness of the need for microbiologic regulations in assessing "high level" disinfection.

Colony Count, Microbial↗
PubMed1977

Decrease of lysosomal enzymes in macrophages incubated with supernatants of mixed culture of allograft donor and recipient lymphocytes.

Incubation of mouse peritoneal macrophages (thioglycollate-induced) for 72 hours with the supernatant of a mixed lymphocyte culture (MLC) between skin allograft donor and recipient results in a decrease of macrophage acid phosphatase (EC 3.1.3.2.) and beta glucuronidase (EC 3.2.1.31). The alteration of these lysosomal enzymes is not explained by a loss of cell viability.

Acid Phosphatase↗
PubMed1994

Okadaic acid stimulates inflammatory cytokine gene transcription in murine peritoneal macrophages.

The involvement of protein phosphorylation in controlling proinflammatory cytokine gene expression by mononuclear phagocytes has been examined using okadaic acid (OA), a specific inhibitor of protein phosphatases 1 and 2A. OA (100 nM) was able to stimulate accumulation of TNF alpha and IP-10 mRNAs in thioglycollate-elicited peritoneal macrophages from C57B1/6 mice. The responses to OA or LPS were similar in several respects. The OA- and LPS-stimulated increases in IP-10 and TNF alpha mRNA were mediated through increases in the transcriptional activity of the genes as measured by nuclear run-on analysis. Both OA- and LPS-stimulated mRNA accumulation were independent of protein synthesis. Furthermore, OA and LPS resulted in elevated kappa B binding activity in treated macrophages which coincided temporally with the increased transcriptional activity of the two cytokine genes. The polypeptide composition of kappa B motif binding complexes from LPS- or OA-treated macrophages was similar. However, OA-induced expression of the TNF alpha and IP-10 genes was markedly delayed (detectable expression was only seen at 4-8 hr after stimulation) relative to that seen in LPS-stimulated macrophages in which both transcription and accumulation of mRNA can be seen within 30 min to 1 hr. Furthermore, the combination of LPS and OA had differential effects on TNF alpha and IP-10 mRNA levels; TNF alpha mRNA expression was prolonged in cells stimulated with LPS plus OA as compared to cells treated with LPS alone. This difference was the result of an increase in the half-life of cytoplasmic TNF alpha mRNA. No similar effect was seen on IP-10 mRNA stability. Thus, although protein phosphorylation appears to be important in regulating cytokine mRNA levels, OA and LPS most likely function via at least partially distinct cellular mechanisms.

Animals↗
PubMed2000

Activation state alters the effect of dietary fatty acids on pro-inflammatory mediator production by murine macrophages.

Studies investigating the effect of dietary fats on pro-inflammatory cytokine production by macrophages (M phis) have yielded conflicting results. We hypothesised that this may be due to the different capacities of the M phis studied commonly (resident, thioglycollate-elicited) to produce prostaglandin E(2)(PGE(2)) and leukotriene B(4)(LTB(4)) which inhibit and stimulate, respectively, tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) production. To investigate this, male C57Bl6 mice were fed for 6 weeks on a low fat (LF) diet or on high fat diets which contained coconut oil (CO), olive oil (OO), safflower oil (SO) or fish oil (FO) as the main fat source. Production of TNF-alpha, IL-1 beta, PGE(2)and LTB(4)by lipopolysaccharide-stimulated resident and thioglycollate-elicited (i.e. inflammatory) peritoneal M phis was measured. PGE(2)production by both inflammatory and resident M phis was significantly decreased by FO feeding. FO also decreased LTB(4)production by resident M phis compared with LF feeding. Production of both cytokines by inflammatory M phis decreased with increasing unsaturation of the high fat diets, such that cells from FO-fed mice showed significantly decreased production of TNF-alpha and IL-1 beta compared to those from mice fed on each of the other diets. In contrast, resident M phis from mice fed FO showed increased TNF-alpha production compared to those from CO-fed mice. Thus, FO feeding decreases production of TNF-alpha and IL-1 beta by inflammatory M phis and increases production of TNF-alpha by resident M phis, at least in comparison to some other dietary fats. These results indicate the mechanisms by which dietary fats exert their effects upon pro-inflammatory cytokine production are most likely different for resident and inflammatory M phis.

Animals↗
PubMed1982

Release of platelet-activating factor (PAF-acether) and leukotrienes C and D from inflammatory macrophages.

Macrophages (M phi) isolated from the peritoneal cavity of C57BL/6 mice were either untreated or treated with various eliciting agents (thioglycollate, sodium caseinate) or with an activating agent bacillus Calmette Guérin (BCG). The various populations were assessed for their ability to release platelet-activating factor (PAF-acether), an ether phospholipid mediator, and slow-reacting substance (SRS), a lipoxygenase arachidonic acid derivative. PAF-acether was recovered in higher amounts form BCG M phi than from resident M phi, whereas elicited M phi exhibited a marked decreased ability to release this mediator. Such variations were only quantitative as evidenced by the similar enzyme sensitivity and high pressure liquid chromatography (HPLC) retention times of the various PAF-acether-containing supernatants. Resident, BCG- and sodium caseinate-induced M phi released similar amounts of SRS, whereas thioglycollate M phi exhibited once again a marked decreased ability to release this mediator. Comparing retention times on HPLC of resident and BCG M phi SRS with those of synthetic leukotrienes C and D, molecular variations were noted. Even though both M phi populations released higher amounts of leukotrienes C than D, the D/C ratio was higher in BCG M phi than in resident M phi. These results show that different environmental factors can influence the release of PAF-acether and leukotrienes from M phi.

Animals↗
PubMed1993

Lipoxygenase-derived mediators may be involved in in vivo neutrophil migration induced by Bothrops erythromelas and Bothrops alternatus venoms.

Bothrops erythromelas (BEV) and B. alternatus (BAV) venoms induced a dose-dependent neutrophil migration when injected into rat peritoneal cavities (20-160 micrograms/cavity). These venoms (80 micrograms/rat) also induced neutrophil migration in the air pouch model of inflammation. This migratory response seemed to be related to the phospholipase A2 (PLA2) activity of the venoms. BAV had approximately two times more PLA2 activity than BEV, and the neutrophil migration induced by the former venom was two to three-fold greater than that observed with the latter. Heated (90 degrees C for 5 min) BEV lost about 50% of its PLA2 activity and this was accompanied by a corresponding loss in the ability to induce neutrophil chemotaxis. Dexamethasone (0.5 mg/kg, s.c.), an indirect inhibitor of PLA2 activity, also abolished the neutrophil migration induced by both venoms. Since NDGA (100 mg/kg, s.c.) and dexamethasone, but not indomethacin (2 mg/kg, s.c.), strongly reduced the neutrophil migration induced by both bothropic venoms, it is suggested that arachidonate-derived lipoxygenase metabolites such as leukotriene B4 act as the chemotactic mediators. Macrophages could be the main cellular source of such metabolites since they are the predominant resident cells in the rat air pouch, and the migratory response of BEV and BAV into peritoneal cavities was potentiated in rats pretreated with thioglycollate. The neutrophil migration induced by BEV and BAV was not due to endotoxin contamination since heated BEV showed no effect and polymyxin B-treated BAV still remained active.

Animals↗
PubMed1971

Characterization of the late steps of microbial heme synthesis: conversion of coproporphyrinogen to protoporphyrin.

Cell-free extracts of various cytochrome-containing, heterotrophic microorganisms were examined for ability to convert coproporphyrinogen to protoporphyrin. Extracts of Escherichia coli and Pseudomonas denitrificans readily accumulated large amounts of protoporphyrin when assayed under aerobic conditions. However, protoporphyrin did not accumulate under either aerobic or anaerobic conditions of assay or in the presence of various supplements in extracts of the aerobe Micrococcus lysodeikticus, the facultative anaerobe Staphylococcus aureus, or the anaerobe Vibrio succinogenes. Protoporphyrin also accumulated when extracts of E. coli and P. denitrificans were incubated aerobically with the early heme precursor, delta-amino levulinic acid (ALA). This protoporphyrin accumulation was markedly stimulated by the iron chelator, o-phenanthroline. Extracts of S. aureus and M. lysodeikticus accumulated coproporphyrin, but not protoporphyrin when incubated with ALA. The enzyme system in extracts of E. coli which converts coproporphyrinogen to protoporphyrin under aerobic conditions of assay was also partially characterized. This conversion was stimulated by the iron chelator, o-phenanthroline, the respiratory inhibitor, cyanide, and the reducing agent, thioglycolate. Dialysis of the extract did not diminish enzyme activity. Certain alternate electron acceptors and nitrite caused a marked inhibition of the conversion. These results indicate that this late step in heme synthesis, the conversion of coproporphyrinogen to protoporphyrin, can be readily demonstrated in extracts of some, but not all, cytochrome-containing bacteria and that the aerobic conversion in E. coli exhibits many characteristics similar to those demonstrated for the aerobic conversion previously studied in liver mitochondria.

Aerobiosis↗
PubMed1985

A lectinlike receptor on murine macrophage cell line cells, Mm1: involvement of sialic acid-binding sites in opsonin-independent phagocytosis for xenogeneic red cells.

The recognition mechanism of xenogenic red cells by mouse macrophages was studied by using established cell lines. Approximately 30% of cell line cells Mm1 which lack la antigen, as well as of thioglycollate-induced peritoneal macrophages from SL/Am mice (TGC-M phi) could ingest unopsonized quail red cells (QRC). In contrast, an undifferentiated type of cell line, M1-, and another type of macrophage cell line, Mk1-C, possessing accessory cell activity in association with the expression of la antigen, had no phagocytic activity for QRC. Approximately 80% of Mm1 cells, as well as TGC-M phi formed rosettes with QRC, whereas M1- and Mk1-C cells did not; indicating that specific binding sites for QRC are expressed on a large portion of Mm1 and TGC-M phi but not on M1- and Mk1-C cells. No requirement of divalent cation (Mg++, Ca++) and metabolic energy was observed for rosette formation between Mm1 cells and QRC. Protease treatment of Mm1 cells eliminated the rosetting activity, whereas periodate oxidation of glycosidase treatment slightly enhanced this activity, suggesting the involvement of surface protein in binding sites of Mm1 cells. In contrast to these findings on Mm1 cells, binding components of QRC were sensitive to periodate oxidation or neuraminidase treatment but resistant to protease, suggesting that the terminal sialic acid residues of carbohydrate of QRC are recognized by Mm1 cells. Furthermore, N-acetylneuraminic acid (NeuNAc) inhibited the rosette formation and promoted the dissociation of rosettes already formed. N-Acetylneuramin lactose (Neu-NAc-Lact) was more efficient in rosette inhibition than NeuNAc. These sugars also blocked the phagocytosis of QRC by Mm1 cells but had no effect on either Fc-mediated phagocytosis or latex ingestion. These results suggest that phagocytosis of QRC by murine macrophages is mediated by protease-sensitive binding sites recognizing terminal sialic acid residues of QRC in conjunction with additional carbohydrates.

Animals↗
PubMed1991

The cysteine transport system of Saccharomyces cerevisiae.

Although Saccharomyces cerevisiae strains had different cysteine uptake activities, they revealed monophasic uptake kinetics and had the same KT (83.3 microM). The optimal pH of cysteine uptake was between 4.5 and 5.0, but the activity was quickly lost if cells were kept in buffer. When the activity was measured in the growth medium, it increased in the presence of EDTA and greatly decreased in the presence of mercuric chloride. Thioglycol as well as metabolic inhibitors such as dinitrophenol and azide were inhibitory. Homocysteine and methionine were competitive and non-competitive inhibitors, respectively. Cysteamine and cysteic acid were not inhibitory. From these observations, we conclude that the system mediating uptake of cysteine is specific (we thus name it the cysteine transport system) and that the cysteine transport system recognizes not only the SH-group but also amino- and carboxyl-groups. In wild-type strains the cysteine transport system was derepressed only when the cells were incubated without any sulfur source. On the other hand, in cysteine-dependent mutants, cysteine uptake activity increased with increase of exogenous supply of cysteine, glutathione or methionine. From this result, we suspect that the cellular cysteine level is the limiting factor for biosynthesis of the cysteine transport system in cysteine-dependent strains.

Biological Transport↗
PubMed2001

Regulation of leukocyte recruitment by polypeptides derived from high molecular weight kininogen.

Proteolytic cleavage of single-chain, high molecular weight kininogen (HK) by kallikrein releases the short-lived vasodilator bradykinin and leaves behind a two-chain, high molecular weight kininogen (HKa) reported to bind to the beta2-integrin Mac-1 (CR3, CD11b/CD18, alphaMbeta2) on neutrophils and exert antiadhesive properties by binding to the urokinase receptor (uPAR) and vitronectin. We define the molecular mechanisms for the antiadhesive effects of HK related to disruption of beta2-integrin-mediated cellular interactions in vitro and in vivo. In a purified system, HK and HKa inhibited the binding of soluble fibrinogen and ICAM-1 to immobilized Mac-1, but not the binding of ICAM-1 to immobilized LFA-1 (CD11a/CD18, alphaLbeta2). This inhibitory effect could be attributed to HK domain 5 and to a lesser degree to HK domain 3, consistent with the requirement of both domains for binding to Mac-1. Accordingly, HK, HKa, and domain 5 inhibited the adhesion of Mac-1 but not LFA-1-transfected K562 human erythroleukemic cells to ICAM-1. Moreover, adhesion of human monocytic cells to fibrinogen and to human endothelial cells was blocked by HK, HKa, and domain 5. By using peptides derived from HK domain 5, the sequences including amino acids H475-G497 (and to a lesser extent, G440-H455) were identified as responsible for the antiadhesive effect, which was independent of uPAR. Finally, administration of domain 5 into mice, followed by induction of thioglycollate-provoked peritonitis, decreased the recruitment of neutrophils by approximately 70% in this model of acute inflammation. Taken together, HKa (and particularly domain 5) specifically interacts with Mac-1 but not with LFA-1, thereby blocking Mac-1-dependent leukocyte adhesion to fibrinogen and endothelial cells in vitro and in vivo and serving as a novel endogenous regulator of leukocyte recruitment into the inflamed tissue.

Amino Acid Sequence↗
PubMed2004

Monoclonal antibody analysis of Perkinsus marinus extracellular products.

The protozoan oyster parasite Perkinsus marinus releases a complex set of extracellular products (ECP) during in vitro culture. These products have been previously implicated in parasite virulence, and their expression can be altered by medium supplementation with oyster tissue homogenate. Little is known regarding ECP function, regulation, or mechanism of storage and release. Perkinsus marinus ECP were purified from a protein-free medium and used to produce a panel of five monoclonal antibodies. Several of the antibodies recognised series of proteins implying that the ECP may originate from comparatively few parental molecules. The ECP are secreted by several pathways, including the release of one product from an external cell layer, and two other products from two morphologically distinct intracellular compartments. Antibodies against separate epitopes on one protein provided information about possible protein structure. A sandwich ELISA format allowed sensitive quantification of that protein and showed significantly reduced protein expression in oyster tissue homogenate supplemented cultures. Immunopurification allowed tandem mass spectroscopic amino acid sequencing of that protein. Another antibody was used to characterise the P. marinus cell wall. This antibody specifically bound to trophozoite and tomont walls, and was used to investigate the morphological and antigenic changes in these walls during Ray's fluid thioglycollate medium-induced formation of hypnospores. It was also used to confirm that oyster tissue homogenate supplementation could induce formation of hypnospores. This antibody labeled P. marinus cells in fixed oyster tissue in a species-specific manner.

Amino Acid Sequence↗
PubMed1990

Selective reduction of fatty acid oxidation in colonocytes: correlation with ulcerative colitis.

Attempts were made to define which fatty acid (2:0 to 18:1) was optimally oxidized by isolated colonocytes (colonic epithelial cells) and to select inhibitors of fatty acid oxidation which would be analogous in their action to the inhibition of fatty acid oxidation observed in colonocytes involved with ulcerative colitis. Isolated colonic epithelial cells of Sprague-Dawley rats were used with 2-mercaptoacetate, dichloroacetate, 3-mercaptopropionate, 4-mercaptobutyrate, 4-sulfatebutyrate, 2-bromobutyrate, sulfite ions and nitrite ions. n-Butyrate (4:0) was maximally oxidized to CO2 and ketone bodies (mean value 5.46 mumols/min/g dry wt). Oxidation of butyrate to CO2 was diminished by 2-bromobutyrate, sulfite ions and all mercapto fatty acids. Both fatty acid oxidation and glucose oxidation were significantly inhibited by 2-bromobutyrate, while mercapto fatty acids and sulfite inhibited fatty acid oxidation (p less than 0.01) without significantly changing glucose oxidation. Observation with 2-mercaptoacetate and sulfite correlate with early changes of fatty acid oxidation observed in cases of ulcerative colitis, and warrant further study with isolated colonocytes of man.

3-Mercaptopropionic Acid↗
PubMed1995

Uptake by macrophages of low-density lipoprotein damaged by nitrogen dioxide in air.

In order to know whether nitrogen dioxide, an environmental and endogenous free radical toxin, can participate in the formation of atherosclerotic lesions, damage to low-density lipoprotein (LDL) by nitrogen dioxide and uptake of the damaged LDL by macrophages were investigated. A solution of LDL at pH 7.5 was exposed to an atmosphere of nitrogen dioxide (70 ppm) in air at 37 degrees C for 5 or 10 h. Lipid oxidation was induced by the exposure as assessed by the formation of thiobarbituric acid reactive substances. Apolipoprotein B was covalently cross-linked via nondisulfide bonds. Fluorescence analysis showed that tryptophan residues were extensively decreased, and amino acid analysis indicated that the contents of histidine, lysine, and tyrosine residues were decreased by 30-40, 10-20, and 20-30%, respectively. Binding of LDL to thioglycolate-induced mouse peritoneal macrophages was markedly increased by the exposure as observed by the binding of mouse erythrocytes coated with LDL. The activity of LDL to convert macrophages into lipid-laden foam cells was also increased by the exposure. Modification of lysine residues of apo B with lipid oxidation products formed by the exposure may be responsible for the uptake by macrophages. The results suggest the possibility that exposure of LDL in vivo to nitrogen dioxide participates in the formation of atherosclerotic lesions.

Air Pollutants↗
PubMed1990

5-series peptido-leukotriene synthesis in mouse peritoneal macrophages: modulation by dietary n-3 fatty acids.

This study was undertaken to elucidate the metabolic fate of dietary eicosapentaenoic acid (20:5n-3), a major n-3 polyunsaturated fatty acid constituent of fish oil, in the mouse peritoneal macrophage. Mice were fed diets containing menhaden fish oil (FO) or safflower oil (SO). After 3 weeks, resident or responsive peritoneal macrophages were isolated and stimulated with zymosan and A23187, respectively. We demonstrate the novel synthesis of leukotriene C5 (LTC5), derived from 20:5n-3, in addition to LTC4 in both resident and responsive macrophages from FO fed mice. The structures of these peptido-leukotrienes were characterized by their retention times on reverse phase high pressure liquid chromatography, by their u.v. absorbance spectra, and by cross-reactivity with peptido-leukotriene antibody. These results demonstrate for the first time that macrophages are capable of metabolizing dietary 20:5n-3 to LTC5, a pentaene peptido-leukotriene.

Animals↗