Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| interference between host resistance to listeria monocytogenes infection and ovalbumin-induced allergic responses in mice. | listeria monocytogenes promotes the induction of the t-helper 1 (th1) cell response, while ovalbumin (ova) induces a th2 cell response and allergic reactions, such as airway hyperreactivity and immunoglobulin e (ige) production. when mice were immunized with ova on day 7 after l. monocytogenes infection, eosinophilia in bronchoalveolar lavage and the production of total ige, ova-specific ige, interleukin-4 (il-4), and il-5 in the circulation were markedly suppressed. cytokine responses, includin ... | 2001 | 11179368 |
| aberrant macrophage and neutrophil population dynamics and impaired th1 response to listeria monocytogenes in colony-stimulating factor 1-deficient mice. | listeria monocytogenes, a facultative intracellular bacterium, has been used extensively to study innate immune responses. macrophages act as hosts for this bacterium as well as a major defense against it. using mice homozygous for a null mutation (csf1(op)) in the gene for the mononuclear phagocytic growth factor colony-stimulating factor 1 (csf-1), we have demonstrated that csf-1-regulated macrophages were essential to defend against a listerial infection. in the absence of csf-1, monocytes we ... | 2001 | 11179357 |
| non-major histocompatibility complex control of antibody isotype and th1 versus th2 cytokines during experimental infection of mice with mycobacterium avium. | infection of different strains of mice with mycobacterium avium has revealed genetic control of the immunoglobulin isotype induced and of the balance between th1 and th2 cytokines. female balb/c or c57bl/10 mice were infected intranasally with 10(5) m. avium organisms. the antibody response was measured over 18 weeks by enzyme-linked immunosorbent assay and western blotting, while numbers of cytokine-producing cells were assessed at 12 to 15 weeks by elispot assay. upon infection, c57bl/10 mice ... | 2001 | 11179347 |
| human lactoferrin and peptides derived from its n terminus are highly effective against infections with antibiotic-resistant bacteria. | since human lactoferrin (hlf) binds to bacterial products through its highly positively charged n terminus, we investigated which of the two cationic domains is involved in its bactericidal activity. the results revealed that hlf lacking the first three residues (hlf(-3n)) was less efficient than hlf in killing of antibiotic-resistant staphylococcus aureus, listeria monocytogenes, and klebsiella pneumoniae. both hlf preparations failed to kill escherichia coli o54. in addition, hlf(-3n) was less ... | 2001 | 11179314 |
| listeria monocytogenes-infected phagocytes can initiate central nervous system infection in mice. | listeria monocytogenes-infected phagocytes are present in the bloodstream of experimentally infected mice, but whether they play a role in central nervous system (cns) invasion is unclear. to test whether bacteria within infected leukocytes could establish cns infection, experimentally infected mice were treated with gentamicin delivered by surgically implanted osmotic pumps. bacterial inhibitory titers in serum and plasma ranged from 1:16 to 1:256, and essentially all viable bacteria in the blo ... | 2001 | 11179297 |
| hijacking and exploitation of il-10 by intracellular pathogens. | macrophages play a central role in infections, as a target for pathogens and in activation of the immune system. interleukin-10 (il-10), a cytokine produced by macrophages, is a potent immunosuppressive factor. some intracellular pathogens specifically target macrophages for infection and use il-10 to dampen the host immune response and stall their elimination from the host. certain viruses induce production of cellular il-10 by macrophages, whereas other viruses encode their own viral il-10 hom ... | 2001 | 11173248 |
| persistent infection with listeria monocytogenes in the kidney induces anti-inflammatory invariant fetal-type gammadelta t cells. | after intraperitoneal inoculation with listeria monocytogenes, gammadelta t cells appear in the peritoneal cavity preceding the appearance of alphabeta t cells. such gammadelta t cells predominantly express t-cell receptor (tcr)vgamma1/vdelta6, develop through an extrathymic pathway, and contribute to host defence against the bacteria. we have observed a gradual increase in gammadelta t cells in kidneys of mice after intrarenal inoculation with l. monocytogenes, which resulted in an unusually lo ... | 2001 | 11168642 |
| liver abscess due to listeria monocytogenes. | 2000 | 11168114 | |
| neonatal listeriosis in algeria: the first two cases. | 2000 | 11168082 | |
| use of live bacterial vaccine vectors for antigen delivery: potential and limitations. | most infectious agents are restricted to the mucosal membranes or their transit through the mucosa constitutes a critical step in the infection process. therefore, the elicitation of an efficient immune response, not only at systemic, but also at mucosal level, after vaccination is highly desirable, representing a significant advantage in order to prevent infection. this goal can be only achieved, when the vaccine formulation is administered by the mucosal route. however, soluble antigens given ... | 2001 | 11166877 |
| from evil to good: a cytolysin in vaccine development. | current vaccination strategies mainly target antigens into the phagosomal, major histocompatibility complex class ii antigen-processing pathway and thus lead predominantly to humoral immune responses. the elicitation of cytotoxic t-cell responses instead requires introduction of antigens into the cytosol of professional antigen-presenting cells (apcs). the intracellular bacterium listeria monocytogenes gains access to the host cell cytosol by means of a cytolysin, listeriolysin o. vaccine resear ... | 2001 | 11166239 |
| secretion of different listeriolysin cognates by recombinant attenuated salmonella typhimurium: superior efficacy of haemolytic over non-haemolytic constructs after oral vaccination. | viable antigen (ag) delivery systems expressing defined pathogen-derived proteins represent powerful candidates for future vaccination strategies. here, recombinant (r)salmonella typhimurium aroa strains secreting listeriolysin (hly) of listeria monocytogenes in haemolytic or non-haemolytic form were constructed to direct these carriers into cytosolic or phagosomal host cell compartments, respectively. oral and intravenous (i.v.) vaccination of mice with either construct induced 'transporter ass ... | 2000 | 11165923 |
| comparison of control of listeria by nitric oxide redox chemistry from murine macrophages and no donors: insights into listeriocidal activity of oxidative and nitrosative stress. | the physiological function of nitric oxide (no) in the defense against pathogens is multifaceted. the exact chemistry by which no combats intracellular pathogens such as listeria monocytogenes is yet unresolved. we examined the effects of no exposure, either delivered by no donors or generated in situ within ana-1 murine macrophages, on l. monocytogenes growth. production of no by the two nonoate compounds papa/no (nh2(c3h6)(n[n(o)no]c3h7) and dea/no (na(c2h5)2n[n(o)no]) resulted in l. monocytog ... | 2001 | 11165873 |
| evaluation of a recombinant listeria monocytogenes expressing an hiv protein that protects mice against viral challenge. | vaccine strategies that utilize cell mediated immunity to control infection will be a necessary component of human immunodeficiency virus (hiv) vaccines. in previous studies we have shown that a listeria monocytogenes recombinant expressing hiv-gag elicits strong cd8+ and cd4+ t cell responses against hiv gag in addition to its own secreted proteins. here, we show that lm-gag can protect mice against a viral challenge with a recombinant vaccinia virus expressing gag, in an antigen specific manne ... | 2001 | 11163666 |
| actin filament nucleation by endosomes, lysosomes and secretory vesicles. | intracellular pathogens such as listeria monocytogenes and vaccinia virus propel themselves through the cytoplasm of mammalian cells by nucleating actin filaments. recently, actin assembly has also been shown to power the movement of intracellular vesicles, and this may be a mechanism underlying endomembrane movement in a variety of physiological contexts. surprisingly, class i myosins have been found to play important roles in both actin nucleation and endomembrane trafficking. | 2001 | 11163138 |
| relationships between ifngamma, il-6, corticosterone, and listeria monocytogenes pathogenesis in balb/c mice. | the relationships between listeria monocytogenes (lm) pathogenesis, based on bacterial load, and serum levels of il-6, ifngamma, and corticosterone (cort) were quantified. serum ifngamma levels increased along with the lm burden; however, with lm burdens > or =3 x 10(6) cfu per spleen, the serum ifngamma level decreased along with a decrease in splenic weight. serum il-6 levels exponentially increased with increases of lm, and the cort level positively correlated with the increase in il-6 and lm ... | 2001 | 11161448 |
| lipopolysaccharide-induced il-18 secretion from murine kupffer cells independently of myeloid differentiation factor 88 that is critically involved in induction of production of il-12 and il-1beta. | il-18, produced as biologically inactive precursor, is secreted from lps-stimulated macrophages after cleavage by caspase-1. in this study, we investigated the mechanism underlying caspase-1-mediated il-18 secretion. kupffer cells constantly stored il-18 and constitutively expressed caspase-1. inhibition of new protein synthesis only slightly reduced il-18 secretion, while it decreased and abrogated their il-1beta and il-12 secretion, respectively. kupffer cells deficient in toll-like receptor ( ... | 2001 | 11160328 |
| direct analysis of the dynamics of the intestinal mucosa cd8 t cell response to systemic virus infection. | the cd8 t cell response to vesicular stomatitis virus infection was characterized in the spleen and intestinal mucosa using mhc tetramers. surprisingly, the primary response persisted in the lamina propria long after the splenic response had declined. furthermore, the response was characterized by a protracted effector phase in which cytolytic activity in the lamina propria, but not in the spleen, was maintained. the appearance of ag-specific cells in the intestinal mucosa was largely, though no ... | 2001 | 11160292 |
| a novel approach of direct ex vivo epitope mapping identifies dominant and subdominant cd4 and cd8 t cell epitopes from listeria monocytogenes. | we used a novel approach for the direct ex vivo identification and characterization of t cell epitopes based on the screening of peptide spot libraries with freshly isolated splenocytes in a sensitive enzyme-linked immunospot (elispot) assay. this technique was applied for the analysis of splenocytes from listeria monocytogenes-infected balb/c and c57bl/6 mice. the screening of peptide spot libraries covering the whole listeriolysin o and p60 of l. monocytogenes confirmed all known cd4 and cd8 t ... | 2001 | 11160235 |
| conventional alpha beta t cells are sufficient for innate and adaptive immunity against enteric listeria monocytogenes. | we have begun to dissect the cellular requirements for generation of immunity against enteric infection by listeria monocytogenes using a novel t(-) b(-) nk(-) mouse strain (mice double deficient for the common cytokine receptor gamma-chain (gamma(c)) and the recombinase-activating gene-2 (rag2/gamma(c) mice). initial experiments showed that c57bl/6 mice and alymphoid rag2/gamma(c) mice had similar kinetics of bacterial accumulation in the spleen, liver, and brain early after intragastric l. mon ... | 2001 | 11160234 |
| neural route of cerebral listeria monocytogenes murine infection: role of immune response mechanisms in controlling bacterial neuroinvasion. | the pathologic features of cerebral listeria monocytogenes infection strongly suggest that besides hematogenous spread, bacteria might also spread via a neural route. we propose that after snout infection of recombination activating gene 1 (rag-1)-deficient mice, l. monocytogenes spreads to the brain via a neural route. the neural route of invasion is suggested by (i) the immunostaining of l. monocytogenes in the trigeminal ganglia (tg) and brain stem but not in other areas of the brain; (ii) th ... | 2001 | 11160006 |
| human endothelial cell activation and mediator release in response to listeria monocytogenes virulence factors. | the interaction of listeria monocytogenes with endothelial cells represents a crucial step in the pathogenesis of listeriosis. incubation of human umbilical vein endothelial cells (huvec) with wild-type l. monocytogenes (egd) provoked immediate strong no synthesis, attributable to listerial presentation of listeriolysin o (llo), as the no release was missed upon employment of a deletion mutant for llo (egd hly mutant) and was reproduced by purified llo. studies of conditions lacking extracellula ... | 2001 | 11159983 |
| staphylococcus caprae strains carry determinants known to be involved in pathogenicity: a gene encoding an autolysin-binding fibronectin and the ica operon involved in biofilm formation. | the atlc gene (1,485 bp), encoding an autolysin which binds fibronectin, and the ica operon, involved in biofilm formation, were isolated from the chromosome of an infectious isolate of staphylococcus caprae and sequenced. atlc (155 kda) is similar to the staphylococcal autolysins atl, atle, aas (48 to 72% amino acid identity) and contains a putative signal peptide of 29 amino acids and two enzymatic centers (n-acetylmuramoyl-l-alanine amidase and endo-beta-n-acetylglucosaminidase) interconnecte ... | 2001 | 11159959 |
| purification and characterization of pcr-inhibitory components in blood cells. | in a recent study, immunoglobulin g in human plasma was identified as a major inhibitor of diagnostic pcr (w. abu al-soud, l. j. jönsson, and p. rådström. j. clin. microbiol. 38:345-350, 2000). in this study, two major pcr inhibitors in human blood cells were purified using size exclusion and anion-exchange chromatographic procedures. based on n-terminal amino acid sequencing and electrophoretic analysis of the purified polypeptides, hemoglobin and lactoferrin were identified as pcr-inhibitor co ... | 2001 | 11158094 |
| identification and molecular analysis of pcsb, a protein required for cell wall separation of group b streptococcus. | group b streptococcus (gbs) is the leading cause of bacterial sepsis and meningitis in neonates. n-terminal sequencing of major proteins in the culture supernatant of a clinical isolate of gbs identified a protein of about 50 kda which could be detected in all of 27 clinical isolates tested. the corresponding gene, designated pcsb, was isolated from a gbs cosmid library and subsequently sequenced. the deduced pcsb polypeptide consists of 447 amino acid residues (m(r), 46,754), carries a potentia ... | 2001 | 11157929 |
| a novel serotype-specific gene cassette (glta-gltb) is required for expression of teichoic acid-associated surface antigens in listeria monocytogenes of serotype 4b. | listeria monocytogenes serotype 4b strains account for about 40% of sporadic cases and many epidemics of listeriosis. mutations in a chromosomal locus resulted in loss of reactivity with all three monoclonal antibodies (mabs) which were specific to serotype 4b and the closely related serotypes 4d and 4e. here we show that this locus contains a serotype 4b-4d-4e-specific gene cassette (3,071 bp) which consists of two genes, glta and gltb, and is flanked by palindromic sequences (51 and 44 nucleot ... | 2001 | 11157924 |
| characterization of recurrent and sporadic listeria monocytogenes isolates from raw milk and nondairy foods by pulsed-field gel electrophoresis, monocin typing, plasmid profiling, and cadmium and antibiotic resistance determination. | following previous surveys to assess the incidence of listeria monocytogenes in raw milk and nondairy foods processed in northern ireland, isolates were characterized as recurrent or sporadic on the basis of multilocus enzyme electrophoresis (mee) analysis and restriction fragment length polymorphism typing. in the present study, 45 representative recurrent and sporadic electrophoretic types (ets) previously identified by mee were subjected to pulsed-field gel electrophoresis (pfge) of genomic d ... | 2001 | 11157252 |
| characterization and pathogenic potential of listeria monocytogenes isolates from the smoked fish industry. | this study was designed to evaluate the hypothesis that some of the listeria monocytogenes subtypes associated with foods, specifically smoked fish, may have an attenuated ability to cause human disease. we tested this hypothesis by using two different approaches: (i) comparison of molecular subtypes found among 117 isolates from smoked fish, raw materials, fish in process, and processing environments with subtypes found among a collection of 275 human clinical isolates and (ii) the evaluation o ... | 2001 | 11157227 |
| control options for listeria monocytogenes in seafoods. | at least three outbreaks of listeriosis associated with seafood have been reported. listeria monocytogenes is widely distributed in the general environment including fresh water, coastal water and live fish from these areas. contamination or recontamination of seafood may also take place during processing and low levels (< 100 cfu/g) of l. monocytogenes are frequently found on seafood including ready-to-eat (rte) products. apart from heat treatment, which is very effective, there are few options ... | 2000 | 11156271 |
| risk assessment used to evaluate the us position on listeria monocytogenes in seafood. | human listeriosis has been associated with consumption of food including seafood. surveillance information on the presence of listeria monocytogenes in seafood products is presented as a background for steps that are being taken to inform risk managers of risks associated with particular food products. united states policy for l. monocytogenes in food has been shaped by our increasing knowledge of the epidemiology of outbreaks and sporadic cases of human listeriosis, the potentially severe publi ... | 2000 | 11156269 |
| present situation in canada regarding listeria monocytogenes and ready-to-eat seafood products. | the present situation regarding listeria monocytogenes and ready-to-eat (rte) seafood is discussed. an updated regulatory policy on l. monocytogenes directs inspection and compliance action to those rte foods capable of supporting growth of the organism and is based on a combination of inspection, environmental sampling and product testing. the incidence of l. monocytogenes in imported seafood products in 1996-1997 and 1997-1998 was 0.88 and 0.3%, respectively. with respect to domestic products, ... | 2000 | 11156268 |
| predictive modelling of the growth and survival of listeria in fishery products. | predictive microbiology provides a powerful tool to aid the exposure assessment phase of 'quantitative microbial risk assessment'. using predictive models changes in microbial populations on foods between the point of production/harvest and the point of eating can be estimated from changes in product parameters (temperature, storage atmosphere, ph, salt/water activity, etc.). thus, it is possible to infer exposure to listeria monocytogenes at the time of consumption from the initial microbiologi ... | 2000 | 11156267 |
| risk assessment of listeria monocytogenes in fish products: some general principles, mechanism of infection and the use of performance standards to control human exposure. | risk assessment is increasingly used as a scientific process to assess the potential for adverse health effects to occur and as a basis for management of unacceptable risks. for each risk assessment activity, the purpose of the assessment should be clearly stated. for listeria monocytogenes, the purpose of risk assessment may be providing information on the relative contribution of listeriosis to infectious diseases. for control purposes, the emphasis may be put on factors contributing to the ri ... | 2000 | 11156266 |
| microbiological criteria for listeria monocytogenes in foods under special consideration of risk assessment approaches. | this paper shortly summarizes data related to risk assessment of listeria monocytogenes. from available data on risk assessment, it is concluded that the levels of l. monocytogenes consumed is an important factor affecting the incidence of listeriosis. foods that do not support the growth of l. monocytogenes are unlikely to be a source of listeriosis, whereas foods that support the growth to high levels, should be the target of risk management efforts. based on current epidemiological informatio ... | 2000 | 11156265 |
| potential of listeria hazard in african fishery products and possible control measures. | africa contributes 5.54 million mt (4.5%) to the world harvest of aquatic organisms. fisheries represent a vital sector for many countries in africa, both for domestic food supply, employment opportunities and foreign exchange earnings. despite the low level of african fish production and export in comparison with the other continents, fish represent the major protein source in many countries (36-58% of animal proteins in c te d'ivoire, congo, senegal, angola) and fishing is a vital activity for ... | 2000 | 11156264 |
| epidemiology of human listeriosis and seafoods. | while rarely diagnosed prior to 1960, more than 10,000 cases of listeriosis were recorded in the medical literature between 1960 and 1982, and thousands more have been reported annually world-wide [rocourt j., 1991. human listeriosis, 1989. who/hpp/fos/91.3, world health organization, geneva, switzerland; rocourt, j., brosch, r., 1992. human listeriosis, 1990. who/hpp/fos/92.3, world health organization, geneva, switzerland; rocourt, j., jacquet, ch., bille, j., 1997. human listeriosis, 1991/199 ... | 2000 | 11156263 |
| listeria monocytogenes in the smoked salmon industry. | smoked salmon is sporadically contaminated with listerial monocytogenes. contamination levels are normally low and consumers are probably seldom exposed to risk concentrations. no clones of l. monocytogenes seem to be specific to smoked salmon, some clones found in smoked salmon having been isolated from several sources, including patients. cold-smoking has been shown to eliminate l. monocytogenes in challenge tests at temperatures from 17.1 to 21.1 degrees c, while from 22.2 to 30 degrees c the ... | 2000 | 11156261 |
| listeria in tropical fish and fishery products. | listeria monocytogenes is considered to be a ubiquitous organism occurring in both terrestrial and aquatic habitats. this organism has been isolated from fish and fishery products from different parts of the world and interestingly the incidence rate reported from tropical fish is rather low. varying methodologies have been used by different investigators to study the incidence of l. monocytogenes in fish. data on virulence of seafood-associated strains are lacking. for quality assurance in the ... | 2000 | 11156260 |
| lessons from an outbreak of listeriosis related to vacuum-packed gravad and cold-smoked fish. | the first lesson learned from this outbreak was that vacuum-packed rainbow trout is not only an excellent medium for the growth of listeria monocytogenes, but may also cause human listeriosis. another lesson is that one single fish processing plant may spread multiple clonal types of l. monocytogenes by selling contaminated products to consumers. thus, when investigating fish-borne outbreaks of listeriosis one should identify and type several isolates of l. monocytogenes from each food and envir ... | 2000 | 11156259 |
| the use of host cell machinery in the pathogenesis of listeria monocytogenes. | the bacterial pathogen, listeria monocytogenes, exploits the host cell's machinery, enabling the pathogen to enter into cells and spread from cell to cell. three bacterial surface proteins are crucial for these processes: internalin and inlb, which mediate entry into cells, and acta, which induces actin polymerisation at one pole of the bacterium and promotes intracellular and intercellular motility. recent studies have identified several of the cellular factors involved in the entry process and ... | 2001 | 11154924 |
| strain-related differences of nonspecific respiratory defense mechanisms in rats using a pulmonary infectivity model. | a number of animal studies have assessed pulmonary host defense mechanisms by inoculating the lungs with the bacterial agent, listeria monocytogenes. most studies use only a single strain of the animal to be tested; however, strain-related differences in responsiveness to pulmonary toxicants have been well documented. it was the goal of this current investigation to measure the pulmonary defense responses of two different strains of rats in a lung infectivity model. fischer 344 (f344) and spragu ... | 2001 | 11153062 |
| in vitro activities of 22 antimicrobial agents against listeria monocytogenes strains isolated in barcelona, spain. the collaborative study group of listeriosis of barcelona. | the in vitro activity of 22 antimicrobial agents against 82 human listeria monocytogenes strains isolated in barcelona from 1994 to 1998 was determined. ampicillin and gentamicin showed good in vitro activity against all strains (mic90: 1 and < or = 0.25 microg/ml, respectively). no resistance to rifampin or co-trimoxazole was detected and only one strain was resistant to tetracycline. of the nine fluoroquinolones tested, clinafloxacin and gemifloxacin were the most active compounds (mic90: 0.12 ... | 2000 | 11146253 |
| variable immunodominance hierarchies for h2-m3-restricted n-formyl peptides following bacterial infection. | h2-m3-restricted presentation of n-formyl methionine (f-met) peptides to cd8(+) t cells provides a mechanism for selective recognition of bacterial infection. in this report we demonstrate that listeria monocytogenes infection induces distinct cd8(+) t cell populations specific for each of the known listeria-derived formyl methionine peptides presented by m3. the sum h2-m3-restricted, listeria-specific t cell response constitutes a major fraction of the total cd8(+) t cell response to primary in ... | 2001 | 11145694 |
| bystander activation of cd8+ t cells contributes to the rapid production of ifn-gamma in response to bacterial pathogens. | the bacterium burkholderia pseudomallei causes a life-threatening disease called melioidosis. in vivo experiments in mice have identified that a rapid ifn-gamma response is essential for host survival. to identify the cellular sources of ifn-gamma, spleen cells from uninfected mice were stimulated with b. pseudomallei in vitro and assayed by elisa and flow cytometry. costaining for intracellular ifn-gamma vs cell surface markers demonstrated that nk cells and, more surprisingly, cd8(+) t cells w ... | 2001 | 11145690 |
| acute bacterial meningitis in adults. a 12-year review. | one hundred three episodes of acute bacterial meningitis in adults hospitalized in edmonton's 2 largest hospitals from 1985 to 1996 were reviewed. cases complicating neurosurgery were excluded. most cases were community-acquired (87%). twenty-three cases remained culture-negative, and there was no statistical relation between culture negativity and antibiotic pretreatment. streptococcus pneumoniae was the predominant pathogen (52.5%), but listeria monocytogenes was the second most common isolate ... | 2000 | 11144034 |
| role of macrophage scavenger receptors in response to listeria monocytogenes infection in mice. | type i and type ii macrophage scavenger receptors (sr-a i/ii) recognize a variety of polyanions including bacterial cell-wall products such as lipopolysaccharide, suggesting a role for sr-a i/ii in immunity against bacterial infection. sr-a i/ii-deficient (msr-a-/-) mice were more susceptible to infection with listeriolysin-o (llo)-producing listeria monocytogenes. after infection, kupffer cells in wild-type (msr-a+/+) mice phagocytized larger numbers of listeria than those in msr-a-/- mice. the ... | 2001 | 11141491 |
| [isolation of listeria spp., aeromonas spp., and vibrio spp. from seafood products]. | forty-one strains of listeria, aeromonas and vibrio have been isolated in 71 samples of seafood, both raw and ready to eat and frozen. l. monocytogenes, detected by pcr also, is found in the smoked salmon only. aeromonas spp. and vibrio spp. are isolated in the raw products (shrimps and shellfish). no relationship is found between the presence of such microrganisms and the common indicator bacteria. finally, the health hazard related to strong contamination and the need to diversify the food saf ... | 2000 | 11140096 |
| nisin-curvaticin 13 combinations for avoiding the regrowth of bacteriocin resistant cells of listeria monocytogenes atcc 15313. | nisin (25-100 iu/ml) and curvaticin 13 (160 au/ml), a bacteriocin produced by lactobacillus curvatus sb13, were shown to have a bactericidal effect against listeria monocytogenes atcc 15313 in tsb-ye broth (ph 6.5), but it was only transitory. regrowth was not due to the loss of bacteriocin activity. cells surviving nisin or curvaticin 13 were more resistant to the respective bacteriocin than the parental strain. survivors to curvaticin 13 were resistant to the class iia bacteriocins (camocin cp ... | 2000 | 11139023 |
| occurrence of and a possible mechanism for resistance to a quaternary ammonium compound in listeria monocytogenes. | in a study of 200 listeria monocytogenes isolates, 10% were determined to be resistant to benzalkonium chloride (bc). serial subcultivation of initially bc sensitive (bc(s)) and bc resistant (bc(r)) isolates in sublethal concentrations of bc resulted in enhanced and approximately equal resistance of all strains to the compound. fifty per cent of the bc(r) isolates showed resistance to ethidium bromide (eb) as well. a proton motive force (pmf)-dependent efflux of eb was demonstrated in bc(r) isol ... | 2000 | 11139022 |
| low-dose irradiation as a measure to improve microbial quality of ice cream. | the present study was undertaken to investigate the efficacy of low-dose irradiation to improve the microbial safety of ice cream. initially three different flavors (vanilla, strawberry and chocolate) of ice cream were exposed, at -72 degrees c, to doses of 1, 2, 5, 10 and 30 kgy to gamma-radiation. irradiation at 1 kgy resulted in reduction of microbial population by one log cycle, thus meeting the requirement limits prescribed by bureau of indian standards. pathogens such as listeria monocytog ... | 2000 | 11139019 |
| incidence of listeria spp. and salmonella spp. in horsemeat for human consumption. | the incidence of salmonella spp., listeria spp. and listeria monocytogenes in horsemeat for human consumption was investigated. one-hundred and twenty-one samples of frozen horsemeat collected from two brazilian abattoirs were analysed over a period of 1 year. twenty-two samples (18.2%) were positive for listeria spp. with nine (7.4%) containing l. monocytogenes. none of the samples harbored salmonella spp. | 2000 | 11139017 |
| pulsed-field gel electrophoresis (pfge) typing of listeria strains isolated from a meat processing plant over a 2-year period. | as part of a hygiene monitoring program in a meat processing plant a total of 131 listeria isolates were detected by sampling different processing areas and meat products within a 2-year period. the isolates were differentiated by means of phenotypic characteristics. furthermore, the genomic apai and smai fragment patterns of all isolates were examined by pulsed-field gel electrophoresis (pfge). pfge using smai and apai yielded 15 (listeria monocytogenes), 20 (listeria innocua) and six (listeria ... | 2000 | 11139016 |
| behaviour of listeria monocytogenes during the manufacture and ripening of manchego and chihuahua mexican cheeses. | the ability of listeria monocytogenes to survive the mexican manchego and chihuahua cheese-making processes and its persistence during the ripening stages of both cheeses was examined. commercial pasteurized and homogenized whole milk was inoculated with listeria monocytogenes (strain atcc 19114) to a level between 2 x 10(6) and 9 x 10(6) cfu/ml. the milk was used to make mexican manchego and chihuahua cheeses in a 25-l vat. mexican manchego cheese was ripened for 5 days and chihuahua cheese for ... | 2000 | 11139015 |
| comparative evaluation of adhesion and biofilm formation of different listeria monocytogenes strains. | thirteen listeria monocytogenes strains were used to grow biofilms on glass surfaces in static conditions at 37 degrees c for up to 4 days. after the initial 3-h adhesion and in subsequent 1-day intervals, cell numbers were determined using standard plate count after swabbing the cells from the glass surface. the three-dimensional structure of in situ biofilms was determined by confocal scanning laser microscopy (cslm). after 3 h incubation, bacterial cells for all 13 strains of l. monocytogenes ... | 2000 | 11139010 |
| hijacking of apoptotic pathwaysby bacterial pathogens. | increasing evidence indicates that apoptosis of the host cell may constitute a defense mechanism to confine the infection by bacterial pathogens. certain pathogens have developed elegant mechanisms to modulate the fate of the host cell, which include induction or blockage of apoptosis. these studies will promote our understanding of the pathogenesis of infectious diseases and aid the development of means for therapeutic intervention. | 2000 | 11137044 |
| molecular studies on the ecology of listeria monocytogenes in the smoked fish processing industry. | we have applied molecular approaches, including pcr-based detection strategies and dna fingerprinting methods, to study the ecology of listeria monocytogenes in food processing environments. a total of 531 samples, including raw fish, fish during the cold-smoking process, finished product, and environmental samples, were collected from three smoked fish processing facilities during five visits to each facility. a total of 95 (17.9%) of the samples tested positive for l. monocytogenes using a com ... | 2001 | 11133446 |
| molecular ecology of tetracycline resistance: development and validation of primers for detection of tetracycline resistance genes encoding ribosomal protection proteins. | phylogenetic analysis of tetracycline resistance genes encoding the ribosomal protection proteins (rpps) revealed the monophyletic origin of these genes. the most deeply branching class, exemplified by tet and otra, consisted of genes from the antibiotic-producing organisms streptomyces rimosus and streptomyces lividans. with a high degree of confidence, the corresponding genes of the other seven classes (tet m, tet s, tet o, tet w, tet q, tet t, and tetb p) formed phylogenetically distinct sepa ... | 2001 | 11133424 |
| evaluation of batch and semicontinuous application of high hydrostatic pressure on foodborne pathogens in salsa. | the effects of high hydrostatic pressure (hpp; 545 mpa) on strains of escherichia coli o157:h7, listeria monocytogenes, enterotoxigenic staphylococcus aureus, and nonpathogenic microorganisms were studied in tomato-based salsa. products were evaluated for the survival of the inoculated pathogens following hpp treatment and after storage at 4 degrees c and 21 to 23 degrees c for up to 2 months. inoculated samples without hpp treatment, stored under the same conditions, were also evaluated to dete ... | 2000 | 11131896 |
| reduction of normal flora by irradiation and its effect on the ability of listeria monocytogenes to multiply on ground turkey stored at 7 degrees c when packaged under a modified atmosphere. | listeria monocytogenes did not multiply faster during storage at 7 degrees c on irradiated than on nonirradiated raw ground turkey, and there was a concentration-dependent inhibition of its multiplication by co2. ground turkey was gamma irradiated at 5 degrees c to 0, 1.5, and 2.5 kgy and inoculated (approximately 100 cfu/g) after irradiation with a cocktail of l. monocytogenes atcc 7644, 15313, 49594, and 43256. the meat was then packaged in air-permeable pouches or under atmospheres containing ... | 2000 | 11131894 |
| isolation of a bacteriocin-producing lactococcus lactis subsp. lactis and application to control listeria monocytogenes in moroccan jben. | use of a bacteriocin-producing lactococcal strain to control listeria monocytogenes in jben. | 2000 | 11123469 |
| effect of various environmental parameters on the recovery of sublethally salt-damaged and acid-damaged listeria monocytogenes. | the influence of supplementing the culture medium with magnesium sulphate, d-glucose, l-cysteine, catalase or lithium chloride, of incubation temperature and of oxygen availability on the recovery of salt- or acid-damaged listeria monocytogenes, was studied on a solid repair medium according to a hadamard matrix, with seven parameters varying between a high and a low level. the most important factors for repair of stressed listeria were further studied with complete factorial design experiments. ... | 2000 | 11123467 |
| behaviour of listeria monocytogenes and autochthonous flora on meat stored under aerobic, vacuum and modified atmosphere packaging conditions with or without the presence of oregano essential oil at 5 degrees c. | the effect of aerobic, modified atmosphere packaging (map; 40% co2/30% o2/30% n2) and vacuum packaging (vp) on the growth/survival of listeria monocytogenes on sterile and naturally contaminated beef meat fillets was studied in relation to film permeability and oregano essential oil. the dominant micro-organism(s) and the effect of the endogenous flora on the growth/survival of l. monocytogenes were dependent on the type of packaging film. the fact that l. monocytogenes increased whenever pseudo ... | 2000 | 11123463 |
| listeria monocytogenes modulates macrophage cytokine responses through stat serine phosphorylation and the induction of suppressor of cytokine signaling 3. | macrophage activation as part of natural resistance to infection is caused by stimulation with ifn-gamma and by the invading microorganisms or microbial products. infection of macrophages with the gram-positive bacterium listeria monocytogenes for short periods before activation with ifn-gamma increased the phosphorylation of transcription factor stat1 at s727 and thereby the expression of ifn-gamma-induced genes. by contrast, persistent infection with viable bacteria or treatment with heat-kill ... | 2001 | 11123325 |
| early programming of t cell populations responding to bacterial infection. | the duration of infection and the quantity of ag presented in vivo are commonly assumed to influence, if not determine, the magnitude of t cell responses. although the cessation of in vivo t cell expansion coincides with bacterial clearance in mice infected with listeria monocytogenes, closer analysis suggests that control of t cell expansion and contraction is more complex. in this report, we show that the magnitude and kinetics of ag-specific t cell responses are determined during the first da ... | 2000 | 11120806 |
| immunotoxic effects of inorganic lead on host resistance of mice with different circling behavior preferences. | we have observed differential immune responses in mice with different circling preferences, which are posited to reflect interindividual immune response differences influenced by brain laterality effects on neuroimmune circuits. in this study, we have investigated the influence of inorganic lead (pb) and/or listeria monocytogenes (lm) infection on the cytokine and corticosterone (cort) levels of mice grouped by lateralized behavior. pb increased the lm susceptibility of mice with both left (lc)- ... | 2000 | 11120598 |
| the effect of thermal stress on campylobacter coli. | enteropathogenic campylobacter jejuni, camp. coli and camp. lari are currently the most common cause of acute infectious diarrhoeal illness in the uk. many domestic animals, including pigs, act as natural reservoirs for these organisms and infection may occur through the ingestion of contaminated foodstuffs. the safety of locally produced porcine liver was assessed in relation to the heat susceptibility of campylobacter spp. present in eviscerated product. | 2000 | 11119166 |
| carbon tetrachloride is immunosuppressive and decreases host resistance to listeria monocytogenes and streptococcus pneumoniae in female b6c3f1 mice. | carbon tetrachloride (ccl(4)) is an environmental contaminant that has been detected in ambient air, seawater, surface-water and snow. the immunotoxic potential of ccl(4) was evaluated in female b6c3f1 mice. the animals were administered with ccl(4) daily for 14 days at doses of 50, 100, 500 or 1000 mg/kg body weight by gavage with corn oil as a vehicle. exposure to ccl(4) resulted in an increase of liver weight but not the body weight and the weights of brain, spleen, lungs, thymus and kidneys. ... | 2000 | 11118673 |
| comparative investigations of listeria monocytogenes isolated from a turkey processing plant, turkey products, and from human cases of listeriosis in denmark. | listeria monocytogenes was isolated from critical control points in a danish turkey processing plant, from turkey products and from cases of human listeriosis. during processing in the plant the prevalence of l. monocytogenes ranged from 25.9 to 41.4%. cleaning and disinfection decreased the prevalence to 6.4%. isolates of l. monocytogenes were characterized by pulsed-field gel electrophoresis (pfge) using restriction endonuclease apai. identical dna types were obtained from turkey products and ... | 2000 | 11117953 |
| pharmacological and antimicrobial studies on different tea-tree oils (melaleuca alternifolia, leptospermum scoparium or manuka and kunzea ericoides or kanuka), originating in australia and new zealand. | three different species of myrtaceae growing in australia and new zealand are known as 'tea-tree': the australian tea tree (melaleuca alternifolia), the new zealand manuka (leptospermum scoparium) and kanuka (kunzea ericoides). all three essential oils are used by aromatherapists, although only melaleuca has been tested for toxicity, and its antimicrobial effects studied. the pharmacology and antimicrobial activity of the three 'tea-tree' oils was determined using guinea-pig ileum, skeletal musc ... | 2000 | 11114000 |
| allergen immunotherapy: novel approaches in the management of allergic diseases and asthma. | currently available pharmacotherapies for allergic diseases and asthma, which are serious public health problems, are aimed primarily at neutralizing effector molecules and inflammatory mediators such as histamine and leukotrienes or at inhibiting the function of inflammatory cells such as eosinophils and th2 lymphocytes. while this approach is effective in controlling symptoms, these therapies have a limited capacity to alter the natural course of allergic diseases and asthma, and discontinuati ... | 2000 | 11112358 |
| detection of listeria monocytogenes by polymerase chain reaction in intestinal mucosal biopsies from patients with inflammatory bowel disease and controls. | components of the intestinal microflora are believed to play an important role in the pathogenesis of inflammatory bowel disease (ibd) in genetically susceptible hosts acting either as a non-specific antigenic stimulus or as a specific pathogen. listeria monocytogenes has been suggested as an organism with the potential to cause ibd. the objective of the present study was to investigate the prevalence of l. monocytogenes dna in intestinal biopsies from patients with ibd and from non-ibd controls ... | 2000 | 11106094 |
| stimulatory action of pluchea quitoc extract on the hematopoietic response during murine listeriosis. | the importance of both granulocytes and macrophages in the response to listeria monocytogenes infection make this infection a suitable choice to investigate the effects of pluchea quitoc on hematopoiesis. a significant depletion of bone marrow granulocyte-macrophage progenitor cells (cfu-gm) was observed at 48 and 72 h after intraperitoneal infection of mice with 1 x 10(4) l. monocytogenes. however, the treatment of infected animals with p. quitoc ethanolic extract (250, 500 or 1000 mg/kg) given ... | 2000 | 11105784 |
| tnf-alpha blockade by a dimeric tnf type i receptor molecule selectively inhibits adaptive immune responses. | tumor necrosis factor-alpha (tnf-alpha) is a mediator of severe inflammatory processes, including rheumatoid arthritis. suppression of tnf with a soluble type i or type ii receptor molecule (tnf-ri or tnf-rii) has the potential to decrease cytokine levels and modulate inflammatory diseases in humans. however, it has recently been reported that treatment of mice with a tnf-ri:fc immunoadhesin protein augmented gram positive infections and subsequent mortality. to determine if tnf-alpha blockade w ... | 2000 | 11105778 |
| a cross-sectional study on the prevalence of listeria monocytogenes and salmonella in new york dairy herds. | as part of our long-term objective of assessing risk for listeria monocytogenes and salmonella spp. in dairy herds, we carried out a cross-sectional study to determine the prevalence of the two organisms. the study population consisted of a sample of dairy herds enrolled in the quality milk promotion services at cornell during the period of april 1998 to march 1999. the sample was stratified by geographical region to assure representation. four hundred and four dairy farms were enrolled in the s ... | 2000 | 11104262 |
| quantifying translocation of listeria monocytogenes in rats by using urinary nitric oxide-derived metabolites. | the urinary nitric oxide metabolites no(2)(-) and no(3)(-) (summed as no(x)) are a noninvasive, quantitative biomarker of translocation of salmonella from the intestinal lumen to systemic organs. listeria monocytogenes is a food-borne gram-positive pathogen that can also cross the intestinal epithelium. in this study, we tested the efficacy of urinary no(x) as a marker of listeria translocation. rats (eight per group) were orally infected with increasing doses of l. monocytogenes; control rats r ... | 2000 | 11097905 |
| bacterial meningitis. | initial empiric therapy for community-acquired bacterial meningitis should be based on the possibility that penicillin-resistant pneumococci may be the etiologic organisms and, hence, should include a combination of third-generation cephalosporin (cefotaxime or ceftriaxone) and vancomycin. ampicillin should be included if the patient has predisposing factors that are associated with a risk for infection with listeria monocytogenes. bacterial isolates from the cerebrospinal fluid should be tested ... | 1999 | 11096704 |
| effect of acid-adaptation on listeria monocytogenes survival and translocation in a murine intragastric infection model. | acid tolerance response mechanisms can greatly influence listeria monocytogenes survival in low ph foods. in the present paper, the effect of acid-adaptation together with control of gastric ph level on l. monocytogenes survival and translocation was analyzed after intragastric inoculation in the balb/c mouse model. our results showed that acid-adaptation led to an increase in resistance to the first barrier constituted by the low gastric ph and that inoculation at alkaline ph had a synergistic ... | 2000 | 11094295 |
| human dendritic cells infected by listeria monocytogenes: induction of maturation, requirements for phagolysosomal escape and antigen presentation capacity. | an important feature of microbial infections is the ability of the microorganisms to interfere with and modulate the induction of host immune reactions. however, little is known about the effects of broad host range pathogens such as listeria monocytogenes on similar cell types in different hosts. here we examine the effects of the human and animal pathogen l. monocytogenes on human dendritic cells (dc) since this type of cells is essential for the initiation of immune responses. listeria are ph ... | 2000 | 11093163 |
| role of sigma(b) in adaptation of listeria monocytogenes to growth at low temperature. | the activity of sigma(b) in listeria monocytogenes is stimulated by high osmolarity and is necessary for efficient uptake of osmoprotectants. here we demonstrate that, during cold shock, sigma(b) contributes to adaptation in a growth phase-dependent manner and is necessary for efficient accumulation of betaine and carnitine as cryoprotectants. | 2000 | 11092874 |
| the impact of the quality of silage on animal health and food safety: a review. | this paper reviews the microbiological aspects of forage preserved by ensilage. the main principles of preservation by ensilage are a rapid achievement of a low ph by lactic acid fermentation and the maintenance of anaerobic conditions. the silage microflora consists of beneficial micro-organisms, i.e. the lactic acid bacteria responsible for the silage fermentation process, and a number of harmful micro-organisms that are involved in anaerobic or aerobic spoilage processes. micro-organisms that ... | 2000 | 11087133 |
| depletion of a gamma delta t cell subset can increase host resistance to a bacterial infection. | gammadelta t lymphocytes have been shown to regulate immune responses in diverse experimental systems. because distinct gammadelta t cell subsets, as defined by the usage of certain tcr v genes, preferentially respond in various diseases and disease models, we have hypothesized that the various gammadelta t cell subsets carry out different functions. to test this, we compared one particular gammadelta t cell subset, the vgamma1(+) subset, which represents a major gammadelta t cell type in the ly ... | 2000 | 11086087 |
| oppa of listeria monocytogenes, an oligopeptide-binding protein required for bacterial growth at low temperature and involved in intracellular survival. | we identified a new oligopeptide permease operon in the pathogen listeria monocytogenes. this opp operon consists of five genes (oppa, oppb, oppc, oppd, and oppf) and displays the same genetic organization as those of several bacterial species. the first gene of this operon, oppa, encodes a 62-kda protein sharing 33% identity with oppa of bacillus subtilis and is expressed predominantly during exponential growth. the function of oppa was studied by constructing an oppa deletion mutant. the pheno ... | 2000 | 11083832 |
| clpc atpase is required for cell adhesion and invasion of listeria monocytogenes. | we studied the role of two members of the 100-kda heat shock protein family, the clpc and clpe atpases, in cell adhesion and invasion of the intracellular pathogen listeria monocytogenes. during the early phase of infection, a clpc mutant failed to disseminate to hepatocytes in the livers of infected mice whereas the invasive capacity of a clpe mutant remained unchanged. this was confirmed by a confocal microscopy study on infected cultured hepatocyte and epithelial cell lines, showing a strong ... | 2000 | 11083831 |
| regulation of antigen-specific cd8+ t cell homeostasis by perforin and interferon-gamma. | t cell memory depends on factors that regulate expansion and death of these cells after antigenic stimulation. mice deficient in perforin and interferon-gamma (ifn-gamma) exhibited increased expansion, altered immunodominance, and decreased death of antigen-specific cd8+ t cells after infection with an attenuated strain of listeria monocytogenes, which was cleared from these mice. expansion of cd8+ t cells was controlled by perforin, whereas ifn-gamma regulated immunodominance and the death phas ... | 2000 | 11082062 |
| inib-dependent internalization of listeria is mediated by the met receptor tyrosine kinase. | the listeria monocytogenes surface protein inlb promotes bacterial entry into mammalian cells. here, we identify a cellular surface receptor required for inlb-mediated entry. treatment of mammalian cells with inlb protein or infection with l. monocytogenes induces rapid tyrosine phosphorylation of met, a receptor tyrosine kinase (rtk) for which the only known ligand is hepatocyte growth factor (hgf). like hgf, inlb binds to the extracellular domain of met and induces "scattering" of epithelial c ... | 2000 | 11081636 |
| alternative strategies for becoming an insider: lessons from the bacterial world. | 2000 | 11081622 | |
| the rpon gene of enterococcus faecalis directs sensitivity to subclass iia bacteriocins. | the final sigma 54 factor has been previously described to be involved in listeria monocytogenes sensitivity to mesentericin y105, a subclass iia bacteriocin. here, we identified the rpon gene, encoding final sigma 54, of enterococcus faecalis jh2-2 and showed that its interruption leads to e. faecalis resistance to different subclass iia bacteriocins. moreover, this rpon mutant remained sensitive to nisin, a class i bacteriocin, suggesting that final sigma 54 is especially involved in sensitivi ... | 2000 | 11080395 |
| combined effect of bacteriocins on the survival of various listeria species in broth and meat system. | the antilisterial efficiency of three bacteriocins from lactic acid bacteria, lactocin 705 (produced by l. casei crl705, 17000 au/ml), enterocin crl35 (produced by e. faecium crl35, 17000 au/ml), and nisin (2000 iu/ml), was tested in broth, individually and in combination against listeria monocytogenes and listeria innocua. both listeria species showed an initial decrease in viable counts followed by the regrowth of the survivors after 1 h in the presence of each bacteriocin. a greater antiliste ... | 2000 | 11080390 |
| stimulation of starter culture for further reduction of foodborne pathogens during salami fermentation. | this study was conducted to determine if stimulated meat starter culture (msc; pediococcus acidilactici) would further control escherichia coli o157:h7, listeria monocytogenes, and staphylococcus aureus during salami fermentation. manganese ion (0.005% of mnso4) was used as a stimulator for the growth and acid production of msc. after 24-h salami fermentation, nonstimulated msc and stimulated msc reduced e. coli o157:h7 levels by 1.3 and 2.3 log10 units, respectively. nonstimulated msc reduced l ... | 2000 | 11079689 |
| efficacy of electrolyzed oxidizing (eo) and chemically modified water on different types of foodborne pathogens. | this study was undertaken to evaluate the efficacy of electrolyzed oxidizing (eo) and chemically modified water with properties similar to the eo water for inactivation of different types of foodborne pathogens (escherichia coli o157:h7, listeria monocytogenes and bacillus cereus). a five-strain cocktail of each microorganism was exposed to deionized water (control), eo water and chemically modified water. to evaluate the effect of individual properties (ph, oxidation-reduction potential (orp) a ... | 2000 | 11078171 |
| effects of combinations of lactoperoxidase system and nisin on the behaviour of listeria monocytogenes atcc 15313 in skim milk. | individual or combined effects of nisin (100 or 200 iu/ml) and the lactoperoxidase system (lps) were analysed against 1 x 10(4) cfu/ml listeria monocytogenes atcc 15313 cells in skim milk, at 25 degrees c for 15 days. nisin induced an immediate bactericidal effect and lps a 48 h bacteriostatic phase which in both cases was followed by re-growth of l. monocytogenes. lps and nisin added together at t0 showed a synergistic and lasting bactericidal effect which after 8 days and until 15 days resulte ... | 2000 | 11078167 |
| microbiological hazard identification and exposure assessment of street food vending in johannesburg, south africa. | one hundred and thirty-two samples of beef, chicken, salad and gravy were collected from two street vendors over eleven replicate surveys to assess microbiological safety and quality. for each food type samples were collected during preparation and holding. dish water was also collected and food preparation surfaces swabbed during preparation and display. standard methods were used to determine aerobic plate counts, enterobacteriaceae counts, coliform counts and spore counts. six hundred and sev ... | 2000 | 11078164 |
| reversable demential syndrome secondary to chronic central nervous system infection by listeria monocytogenes. | 2000 | 11076191 | |
| [details of meningitis in the elderly]. | elderly patients being more at risk for infections than younger people, this study was aimed at defining the epidemiological and clinical features of meningitis in this population, with the objective of improving diagnosis and management. | 2000 | 11075393 |
| immunomodulation in dna damage and repair. | 2000 | 11074359 | |
| oxymetholone modulates cell-mediated immunity in male b6c3f1 mice. | oxymetholone is a synthetic androgen, structurally related to testosterone. it is currently used to treat anemias, but has also been abused as a performance enhancing anabolic steroid by the sport community. concern about its suspected immunomodulatory properties provided the incentive for a detailed investigation into its effects on the mammalian immune system. in this study, male b6c3f1 mice were treated for 14 d with oxymetholone (0, 50, 150, and 300 mg/kg) by gastric intubation, then evaluat ... | 2000 | 11071398 |
| steps and fluctuations of listeria monocytogenes during actin-based motility. | the actin-based motility of the bacterium, listeria monocytogenes, is a model system for understanding motile cell functions involving actin polymerization. although the biochemical and genetic aspects of listeria motility have been intensely studied, biophysical data are sparse. here we have used high-resolution laser tracking to follow the trailing ends of listeria moving in the lamellae of cos7 cells. we found that pauses during motility occur frequently and that episodes of step-like motion ... | 2000 | 11069185 |
| cellular morphology of rough forms of listeria monocytogenes isolated from clinical and food samples. | transmission electron microscopy (tem) studies revealed that rough cell-forms of l. monocytogenes (designated fr variants), isolated from clinical and food samples (and under conditions of sublethal heat stress), consist of either single or paired long-filaments. these fr variants markedly contrast in cell morphology from other previously described avirulent rough-mutants of l. monocytogenes that form long chains consisting of multiple cells of similar size (designated mcr variants). the identit ... | 2000 | 11068915 |
| [listeria infection risk]. | 2000 | 11068613 | |
| cutting edge: off cycling of tnf production by antigen-specific cd8+ t cells is antigen independent. | although they are known for their capacity to kill infected cells, ag-specific cd8(+) t cells elaborate other effector mechanisms, including tnf and ifn-gamma, that contribute to defense against infection. ag-specific cd8(+) t cells rapidly turn on and turn off ifn-gamma production in direct response to ag contact, presumably to minimize the potential immunopathology that could result from inappropriate secretion of this inflammatory mediator. in this study, we show, using in vitro propagated an ... | 2000 | 11067887 |