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Biomedical subjects

S Messier

Publications and source records attributed to S Messier.

At least 19 recordsLinked to original sources
PubMed2005

Shiga toxin production by sausage-borne Escherichia coli O157:H7 in response to a post-processing in vitro digestion challenge.

In order to study the effects of the fermentation-drying procedure and subsequent in vitro digestion on Shiga toxins (Stx) production by Escherichia coli O157:H7, dry sausages were inoculated during the formulation step with pure cultures of strains 5-1 and ATCC 43895. The inoculated sausages were submitted to a minimum (30 min, pH between 3.1 and 3.5) or a maximum (120 min at stepwise adjusting the pH downward) gastric challenge followed by a 240-min pancreatic challenge at pH 8.0 and 37 degrees C. Production of toxins by the overnight culture controls, assessed using the Vero cell assay, was dependent on the pathogen cell concentration. The effect of cell concentration was not relevant in sausage samples and data showed: (a) higher Stx production in contaminated sausage samples than in overnight cultures; (b) the lowest Stx levels were detected with undigested sausage samples; (c) the maximum gastric challenge enhanced Stx production, compared to minimally digested and undigested samples. Reverse transcriptase polymerase chain reaction (RT-PCR) performed on extracts from inoculated, digested (4.5-6 h process) and undigested sausages produced amplicons for both stx1 and stx2 mRNA, suggesting that post-stress expression of stx genes had occurred. Our data suggest that sub-lethal stresses imposed by the fermentation-drying procedure and subsequent digestion of ingested food (i.e. contaminated sausages) may affect the degree to which the surviving E. coli O157:H7 cells express their virulence in vivo.

Animals↗
PubMed2001

Self-efficacy and the progression of functional limitations and self-reported disability in older adults with knee pain.

OBJECTIVES: The prospective relationships between self-efficacy beliefs, in conjunction with measures of knee pain and knee strength, and subsequent decline in both physical performance and self-reported disability among older adults with knee pain were examined. METHODS: In this prospective epidemiological trial, 480 men and women aged 65 years and older who had knee pain on most days of the week and difficulty with daily activity were followed for 30 months. RESULTS: There was a significant interaction of baseline self-efficacy with baseline knee strength in predicting both self-reported disability and stair climb performance. Participants who had low self-efficacy and low strength at baseline had the largest 30-month decline in these outcomes. DISCUSSION: These data underscore the important role that self-efficacy beliefs play in understanding functional decline with chronic disease and aging. Self-efficacy beliefs appear to be most important to functional decline in older adults when they are challenged by muscular weakness in the lower extremities.

Activities of Daily Living↗
PubMed2001

Host response to various treatments to reduce Salmonella infections in swine.

Host response was evaluated following the administration of various treatments, such as probiotics, prebiotics, and vaccination, to reduce Salmonella in swine. Response to the treatments were studied by the evaluation of phagocytosis rates by flow cytometry, by studying the activation of whole-blood phagocytes by bioluminescence, the production of IgA against S. Typhimurium, and by histopathology. Significant differences were observed in the activation of whole-blood phagocytes in all groups of treated pigs (P = 0.0001). In SC54 vaccinated pigs, a significant reduction of Salmonella in the ileum was observed (P < 0.05) and the production of IgA against S. Typhimurium was higher in this group in comparison to uninfected control pigs (P = 0.0007). Furthermore, significant histopathological (P < 0.05) changes were observed in SC54 vaccinated pigs. Villus height and mucus and goblet cells density in the small intestine were reduced in vaccinated pigs in comparison to infected control pigs. Taken together, these findings suggest that SC54 vaccine can stimulate local immunity and reduce the presence of Salmonella in the ileum in swine. Use of SC54 vaccine should thus be considered in further field experiments.

Animals↗
PubMed2001

Three year injury crash records of new licensees with suspensions or invalidity periods lasting 90 days or more.

A subset of new licensees, namely the ones with suspensions or invalidity periods of at least 90 days are studied. This subpopulation is comprised of 3,550 men and 1,295 women for whom the study file contains age, gender, licensing exam performance, and the dates all police reported crashes for the first three years after licensing. This group is compared with the complementary subpopulation of 53,069 men and 58,464 women. The average injury crash rate per year, not prorated, is 0.057 for men and 0.033 for women, about twice the rate for those without lengthy suspensions. These licensees are older, have lower success rates at licensing exams, and have a longer learning period than the others. Separate logistic-normal regression models for men and for women are estimated for the probability of a collision in a year using the available explanatory variables.

Accidents, Traffic↗
PubMed2000

Impact of diabetes on crash risks of truck-permit holders and commercial drivers.

OBJECTIVE: The U.S. and some Canadian government agencies have waived commercial license restrictions for some insulin-using diabetic drivers. However, the U.S. Federal Highway Administration is no longer giving waivers. Scientific evidence to support such regulations has been sparse. This article presents detailed analyses of crash risks for users and nonusers of insulin among diabetic truck-permit holders in Québec, Canada. RESEARCH DESIGN AND METHODS: Diabetic truck-permit holders were group-matched by age to a random sample of healthy permit holders. Data on permits, medical conditions, and crashes involving 13,453 permit holder-years in 1987-1990 were extracted from the files of the public insurer for automobile injuries in Québec. Additional health status data were obtained from the provincial public health insurer. A telephone survey was conducted to collect data on driving patterns and exposure. Risk ratios were estimated using negative binomial regression models. RESULTS: Risk ratios for crashes vary by category of diabetes. Permit holders for single-unit trucks (STs) who are diabetic without complications and not using insulin have an increased crash risk of 1.68 when compared with healthy permit holders of the same permit class. When controlling for risk exposure, commercial drivers with an ST permit and the same diabetic condition have an increased risk of 1.76. Insulin use is not associated with higher crash risk. CONCLUSIONS: The increased crash risk for the group with uncomplicated diabetes not using insulin is a new finding. The lack of consistent increases in crash risks among diabetic commercial drivers with complications or who use insulin may be a "healthy worker effect" masking the real risk, because these licensees have a lower participation rate as professional drivers.

Accidents, Traffic↗
PubMed2000

Assessment of various treatments to reduce carriage of Salmonella in swine.

In this study, different strategies to reduce carriage of Salmonella spp. in pigs were evaluated. Probiotics, prebiotics, vaccination, and acidification of drinking water were assessed as means of reducing Salmonella. Acidification of water, use of egg yolk-specific immunoglobulins, and vaccination with an endotoxin vaccine did not reduce Salmonella excretion in experimentally infected pigs. A reduction of Salmonella in the colonization of mesenteric lymph nodes was observed with the use of bambermycins and a live attenuated vaccine. A reduction in the shedding of S. Typhimurium was also observed after supplementation with fructooligosaccharides in drinking water. The use of probiotics and prebiotics appeared to change the pig fecal bacterial flora as indicated by Gram staining of smears from rectal swabs.

Animals↗
PubMed1999

Distribution of Salmonella in swine herds in Québec.

Five porcine finishing units, previously identified as contaminated by Salmonella, were sampled to identify possible sources of contamination and to study the distribution of Salmonella within the herds. A total of 208 environmental samples were taken and 87 samples (42%) were found contaminated by Salmonella spp. Salmonella was recovered from several types of samples. Among these, fecal material from pens, building environment such as doors, floors, ventilation units, dust and farm accessories were most often found positive. Some of the flies and rodents were also positive. Two of the finishing units were part of an integrated production system and the prevalence and distribution of Salmonella spp. at different production steps of the integrated facilities were studied. Forty-one farms were sampled and a total of 1923 faecal samples in randomly selected pens were analysed. One hundred and fifty-one samples (7.9%) were positive for Salmonella spp. Among the farms sampled, 70.7% (29/41) were positive for isolation of Salmonella. The different levels in the integrated production were unevenly contaminated. Replacement sow (15.9%) and finishing unit for gilts (21.9%) were the most contaminated levels. Ten serotypes of Salmonella (n = 132) were identified in the production pyramid with a predominance of Salmonella Derby (37.1%) and Salmonella Typhimurium (34.1%). Pulse Field Gel Electrophoresis analysis of the various isolates from serotypes and Salmonella Typhimurium, Salmonella Derby and Salmonella Anatum showed no variation in the genetic profiles, within each serotype, suggesting a vertical contamination throughout the different production steps.

Agglutination Tests↗
PubMed1999

Arcobacter butzleri isolated from a diarrhoeic non-human primate.

The bacteriological examination of a faecal specimen from a 20-year-old female rhesus macaque (Macaca mulatta) with diarrhoeal illness revealed the presence of a large number of a relatively new enteric pathogen, Arcobacter butzleri. The animal was from a closed colony of about 60 females, some of them were showing intermittent diarrhoea possibly related to Giardia spp. Conditions for the isolation and identification of A. butzleri are reported, as well as discussions about its role as a primary pathogen and its zoonotic potential.

Animals↗
PubMed1999

Prevalence of Salmonella spp. and Yersinia enterocolitica in finishing swine at Canadian abattoirs.

The prevalence of Salmonella spp. and Yersinia enterocolitica in finishing swine was evaluated using samples of cecal material. Samples were taken at six different slaughterhouses from 1420 healthy, 5-month-old pigs, raised by 223 producers in Quebec (1009 samples), Ontario (283), and Manitoba, Canada (128). Two different broth media (Rappaport-Vassiliadis and Tetrathionate brilliant green) were used for the selective enrichment of Salmonella spp. The recovery of Y. enterocolitica was done by a cold enrichment technique, followed by plating on a selective media (cefsulodin-irgasan-novobiocin agar). Prevalence (with a 95% confidence interval) of Salmonella spp. and Y. enterocolitica were, respectively, 5.2% (4.0 to 6.4%) and 20.9% (18.8 to 23.0%). Overall, 24.6% of the animals tested were positive for one or both of these pathogens. Since only a few herds (2.8%) appeared to be highly contaminated by Salmonella spp., efforts should be undertaken in priority to control this pathogen in those herds.

Abattoirs↗
PubMed1999

Isolation of Actinobacillus suis from a cat's lung.

Actinobacillus suis has been isolated from the lungs of 9-month-old cat. The bacterium was characterized biochemically as well as genetically, and its sensitivity profile to different antimicrobial agents was established. The role of this isolate in the cat's condition is discussed.

Actinobacillus↗
PubMed1997

Detection of Campylobacter jejuni in food and poultry viscera using immunomagnetic separation and microtitre hybridization.

Thermophillic Campylobacter and Camp. jejuni were detected from samples of chicken liver, gall bladder, muscle and contaminated milk and chicken meat after an enrichment step by using immunomagnetic capture of cells with monoclonal antibody against a specific outer membrane protein of thermophilic Campylobacter. The detection of captured cells was achieved using two different hybridization methods. In one of the methods, the captured cells were lysed by guanidine isothiocyanate and the 23S rRNA was reacted with a microtitre plate-immobilized rDNA probe specific for thermophilic Campylobacter. In the other method, the captured cells were subjected to lysis by ultrasonication and the genomic DNA reacted with a microtitre plate-immobilized RNA probe specific for Camp.jejuni. Detection of the RNA-DNA hybrids formed in the wells was carried out using a monoclonal anti-RNA-DNA hybrid antibody.

Animals↗
PubMed1997

Microtitre plate hybridization system for detection of thermophilic Campylobacter rRNA.

A microtitre plate nucleic acid probe hybridization system was developed for the detection of ribosomal RNA from thermophilic Campylobacter (Camp. jejuni, Camp. coli, Camp. lari and Camp. upsaliensis). A specific DNA probe obtained by amplification of 23S rRNA sequences using the polymerase chain reaction technique was immobilized on a microtitre plate, and used for hybridization with target 23S rRNA from cell lysates. The RNA-DNA hybrids thus formed in the wells were detected by an immunoenzymatic assay using a monoclonal antiRNA-DNA hybrid antibody. The sensitivity of this system was 2.7 x 10(4) cells ml(-1). This simple, sensitive and inexpensive hybridization and immunoenzymatic assay system should facilitate the detection of Campylobacter in food and clinical samples.

Bacteriological Techniques↗
PubMed1997

Outbreak of Salmonella give in the province of Quebec.

Salmonellosis due to Salmonella Give involving cows, a goat, and an ostrich over a 6-month period was investigated. Cases were found in 4 different regions. Antimicrobial susceptibility patterns, phagetyping, and pulsed-field gel electrophoresis analyses confirmed that all isolates belonged to the same clone. A common source of infection was suspected.

Animals↗
PubMed1996

Microtitre plate riboprobe system for detection of ultrasonicated Campylobacter jejuni genomic DNA.

Microtitre plate nucleic acid probe hybridization systems were developed for the detection of thermophilic Campylobacter and Campylobacter jejuni. Specific RNA probes obtained by in vitro transcription of DNA templates synthesized by polymerase chain reaction using two sets of specific primers incorporating bacteriophage T7 promoter sequences were immobilized on a microtitre plate. The hybridizations were carried out on samples of genomic DNA sheared by ultrasonication. Optimum conditions for the ultrasonic treatment were determined in order to obtain the highest degree of hybridization with immobilized RNA probe. Finally, detection of RNA-DNA hybrids in the wells was accomplished by an immunoenzymatic assay using a monoclonal anti-RNA-DNA hybrid antibody. This rapid, simple hybridization and immunoenzymatic assay system will facilitate the detection of Campylobacter in foods and clinical samples.

Bacteriological Techniques↗
PubMed1996

Helicobacter canis isolated from a dog liver with multifocal necrotizing hepatitis.

On the basis of biochemical, phenotypic, and 16S rRNA analysis, a novel gram-negative bacterium, isolated from normal and diarrheic dogs as well as humans with gastroenteritis, has been recently named Helicobacter canis. A 2-month-old female crossbred puppy was submitted to necropsy with a history of weakness and vomiting for several hours prior to death. The liver had multiple and slightly irregular yellowish foci up to 1.5 cm in diameter. Histologically, the liver parenchyma contained randomly distributed, occasionally coalescing hepatocellular necrosis, often accompanied by large numbers of mononuclear cells and neutrophils. Sections of liver stained by the Warthin-Starry silver impregnation technique revealed spiral- to curve-shaped bacteria predominantly located in bile canaliculi and occasionally in bile ducts. Aerobic culture of liver was negative, whereas small colonies were noted on Campylobacter selective media after 5 days of microaerobic incubation. The bacteria were gram negative and oxidase positive but catalase, urease, and indoxyl acetate negative; nitrate was not reduced to nitrite, and the organism did not hydrolyze hippurate. The bacteria were also resistant to 1.5% bile. Electron microscopy revealed spiral-shaped bacteria with bipolar sheathed flagella. By 16S rRNA analysis, the organism was determined to be H. canis. This is the first observation of H. canis in active hepatitis in a dog and correlates with recent findings of Helicobacter hepaticus- and Helicobacter bilis-related hepatic disease in mice. Further studies are clearly warranted to ascertain whether H. canis-associated hepatitis is more widespread in canines as well as a cause of previously classified idiopathic liver disease in humans.

Animals↗