bluuebunny/crossref_metadata_2025_split huggingface dataset:
Twitching Motility Contributes to the Role of Pili in Corneal Infection Caused by
Pseudomonas aeruginosa
Authors: Zolfaghar Irandokht , Evans David J. , Fleiszig Suzanne M. J. 
Published: August 2003

ABSTRACT

Twitching motility is a form of surface-associated bacterial movement mediated by type IV pili of
Pseudomonas aeruginosa
. Others have shown that
pilT
and
pilU
mutants, which are piliated but defective in twitching motility, display reduced cytotoxic capacity towards epithelial cells in vitro. Although these mutants efficiently infected lungs in vivo, they were defective in dissemination to the liver. In this study the role of twitching motility in
P. aeruginosa
epithelial cell invasion and corneal disease pathogenesis was explored.
pilU
and
pilT
mutants of
P. aeruginosa
strain PAK were compared to a nonpiliated
pilA
mutant and to wild-type bacteria in their ability to associate with and to invade corneal epithelial cells in vitro and to cause disease in a murine model of corneal infection. As expected, the
pilA
mutant demonstrated reduced association and invasion of corneal epithelial cells (
P
< 0.05 in both cases). The
pilT
mutant, but not the
pilU
mutant, was less invasive than wild-type PAK was (
P
< 0.05 versus
P
= 0.43), while both
pilU
and
pilT
mutants exhibited association levels similar to those of the wild type (
P
= 0.31 and 0.52, respectively). In vivo, all mutants were markedly attenuated in virulence and showed reduced ability to colonize the cornea at 4 and 48 h (all
P
values < 0.02). Thus, twitching motility contributed to the role of pili in corneal disease but was not involved in the role of pili in adherence to or invasion of corneal epithelial cells.
Differential Interleukin-8 and Nitric Oxide Production in Epithelial Cells Induced by Mucosally Invasive and NoninvasiveTrypanosoma cruziTrypomastigotes
Authors: Eickhoff C. S. , Eckmann L. , Hoft D. F. 
Published: August 2003

ABSTRACTTrypanosoma cruzimetacyclic trypomastigotes (MT), but not blood form trypomastigotes (BFT), are highly mucosally infective. We investigated the abilities of MT and BFT to induce inflammation and/or intracellular killing activity within mucosal epithelia. BFT, but not MT, induced marked increases in interleukin-8, GRO-α, MCP-1, and nitric oxide production in HeLa and AGS cells, despite similar infectivities. MT may avoid induction of inflammation as an important biological mechanism facilitating mucosal invasion.
Genetic Variation Influences the B-Cell Response to Immunization with a Pneumococcal Polysaccharide Conjugate Vaccine
Authors: McCool T. L. , Schreiber J. R. , Greenspan N. S. 
Published: August 2003

ABSTRACT

CBA/J mice immunized with pneumococcal 23F-CRM
197
vaccine produce significantly lower titers of 23F-specific antibodies and fewer 23F-specific antibody-secreting cells (ASC) than did BALB/c or (CBA/J × BALB/c)F
1
(CCBAF
1
) mice. The reduced 23F-specific titers of CBA/J versus BALB/c or CCBAF
1
mice are presumably related to lower frequencies of 23F-specific ASC influenced by genetic variation.
Signaling via Toll-Like Receptor 5 Can Initiate Inflammatory Mediator Production by Murine Osteoblasts
Authors: Madrazo Denise R. , Tranguch Susanne L. , Marriott Ian 
Published: August 2003

ABSTRACTMurine osteoblasts express Toll-like receptor 5 (TLR5), and this expression is upregulated following exposure to bacteria or to the TLR5 agonist, flagellin. Importantly, flagellin activates transcriptional regulators and elicits proinflammatory cytokine production, suggesting TLR5 functionality. TLR5 may represent an important mechanism underlying the recognition of bacterial pathogens by osteoblasts during bone infections.
The Small Nucleoid-Binding Proteins H-NS, HU, and Fis Affect
hilA
Expression in
Salmonella enterica
Serovar Typhimurium
Authors: Schechter Lisa M. , Jain Sumita , Akbar Samina , Lee Catherine A. 
Published: August 2003

ABSTRACT

hilA
encodes an activator of
Salmonella enterica
serovar Typhimurium virulence genes and is transcriptionally modulated by environmental conditions. We show that H-NS represses
hilA
under low-osmolarity conditions. H-NS, HU, and Fis also appear to affect the derepression of
hilA
by HilD. Modulation of
hilA
by counteracting repressing and derepressing mechanisms may allow
Salmonella
serovar Typhimurium to regulate its virulence genes in response to different situations in vivo.
Production of FaeG, the Major Subunit of K88 Fimbriae, in Transgenic Tobacco Plants and Its Immunogenicity in Mice
Authors: Huang Yahong , Liang Wanqi , Pan Aihu , Zhou Zhiai , Huang Cheng , Chen Jianxiu , Zhang Dabing 
Published: August 2003

ABSTRACTTransgenic tobacco plants stably expressing recombinant FaeG, which is the major subunit and adhesin of K88ad fimbriae, were obtained. Analysis of sera from immunized mice indicates that in mice, the immunogenicity induced by plant-derived FaeG protein is comparable to that generated with traditional approaches.
Signature-Tagged Mutagenesis of
Pasteurella multocida
Identifies Mutants Displaying Differential Virulence Characteristics in Mice and Chickens
Authors: Harper Marina , Boyce John D. , Wilkie Ian W. , Adler Ben 
Published: August 2003

ABSTRACT

Pasteurella multocida
is the causative agent of fowl cholera in birds. Signature-tagged mutagenesis (STM) was used to identify potential virulence factors in a mouse septicemia disease model and a chicken fowl cholera model. A library of
P. multocida
mutants was constructed with a modified Tn
916
and screened for attenuation in both animal models. Mutants identified by the STM screening were confirmed as attenuated by competitive growth assays in both chickens and mice. Of the 15 mutants identified in the chicken model, only 5 were also attenuated in mice, showing for the first time the presence of host-specific virulence factors and indicating the importance of screening for attenuation in the natural host.
Occupational health guidelines for the management of low back pain: an international comparison
Authors: Staal J B , Hlobil H , van Tulder M W , Waddell G , Burton A K , Koes B W , van Mechelen W 
Published: August 2003

Background:The enormous socioeconomic burden of low back pain emphasises the need for effective management of this problem, especially in an occupational context. To address this, occupational guidelines have been issued in various countries.Aims:To compare available international guidelines dealing with the management of low back pain in an occupational health care setting.Methods:The guidelines were compared regarding generally accepted quality criteria using the AGREE instrument, and also summarised regarding the guideline committee, the presentation, the target group, and assessment and management recommendations (that is, advice, return to work strategy, and treatment).Results and Conclusions:The results show that the quality criteria were variously met by the guidelines. Common flaws concerned the absence of proper external reviewing in the development process, lack of attention to organisational barriers and cost implications, and lack of information on the extent to which editors and developers were independent. There was general agreement on numerous issues fundamental to occupational health management of back pain. The assessment recommendations consisted of diagnostic triage, screening for “red flags” and neurological problems, and the identification of potential psychosocial and workplace barriers for recovery. The guidelines also agreed on advice that low back pain is a self limiting condition and, importantly, that remaining at work or an early (gradual) return to work, if necessary with modified duties, should be encouraged and supported.
A mortality and morbidity study of refinery and petrochemical employees in Louisiana
Authors: Tsai S P , Wendt J K , Cardarelli K M , Fraser A E 
Published: August 2003

Aims:To examine the mortality experience of 4221 employees from 1973 to 1999 and the illness absence patterns for 2203 employees from 1990 to 1999 of a chemical and refinery facility in Louisiana.Methods:Mortality and illness absence data were extracted from the Shell Oil Company’s health surveillance system (HSS). The standardised mortality ratio was used as a measure of mortality risk. Morbidity frequency and duration of absence were calculated by age, sex, and four health risk factors (cigarette smoking, high blood pressure, hypercholesterolaemia, and obesity).Results:Male employees experienced a significant deficit in mortality for all causes of death, all cancers, lung cancer, heart disease, and respiratory disease compared with the corresponding US population. Brain cancer was non-significantly increased, with six observed and five expected deaths; mortality from leukaemia was consistently lower than expected. The majority of employees had no illness absences of six days or longer during the 10 year study period. The loss of productivity (in terms of days of absence) was greater for employees with health risk factors. Ever smoking male employees had a 79% increase of heart disease and more than 50% higher rates of respiratory disease and musculoskeletal disorders compared to non-smokers. Smokers were absent 2.9 and 1.6 more days than non-smokers and ex-smokers, respectively.Conclusions:Regardless of the comparison population, significantly fewer deaths were seen for all causes combined, all cancers, lung cancer, heart disease, or non-malignant respiratory disease. Illness absence rates and duration were higher among employees with health risk factors.
Occupation related pesticide exposure and cancer of the prostate: a meta-analysis
Authors: Van Maele-Fabry G , Willems J L 
Published: August 2003

Aims:To summarise recent literature on the risk of prostate cancer in pesticide related occupations, to calculate the meta-rate ratio, and to compare it to data from meta-analyses previously published.Methods:A meta-analysis of 22 epidemiological studies, published between 1995 and 2001, was conducted in order to pool their rate ratio estimates. Studies were summarised and evaluated for homogeneity and publication bias.Results:The meta-rate ratio estimate, based on 25 estimators of relative risk from 22 studies, was 1.13 (95% CI 1.04 to 1.22). Significant heterogeneity of rate ratios existed among the different studies. Therefore, a stratified analysis was carried out. Major sources of heterogeneity identified were geographic location, study design, and healthy worker effect. Overall, pooled risk estimates for studies derived from Europe were lower than those derived from the USA/Canada. A significant increase in rate ratio was observed for the occupation category of pesticide applicators, whereas no significant increase was observed for farmers. There was no evidence of publication bias.Conclusion:This increased meta-rate ratio for prostate cancer in different pesticide related occupations, including farmers, is very similar to three, previously published, meta-rate ratios for prostate cancer in farmers calculated from studies published before 1995. Although the underlying data do not identify pesticide exposure as an independent cause for prostate cancer, the fact that an increased meta-rate ratio is again obtained points to occupational exposure to pesticides as a possible factor. Future epidemiological studies should focus, as far as possible, on reliable methods to estimate actual exposure.
Smoking and occupation from the European Community Respiratory Health Survey
Authors: McCurdy S A , Sunyer J , Zock J-P , Antó J M , Kogevinas M ,   European Community Respiratory Health Survey Study Group
Published: August 2003

Background:Smoking is among the most important personal and modifiable risk factors for adverse health outcomes. The workplace offers a potentially effective venue for tobacco prevention programmes; identifying occupational groups with high smoking prevalence may assist in targeting such programmes.Aims:To examine smoking prevalence among occupational groups in the European Union.Methods:The European Community Respiratory Health Survey (ECRHS), a cross sectional health survey conducted in 1992–93, was used to examine smoking prevalence by occupation among 14 565 subjects from 30 centres in 14 participating countries.Results:There was an approximately twofold range in smoking prevalence by occupation. For occupational groups with at least 50 subjects, the highest smoking prevalence was seen in metal making and treating for men (54.3%) and cleaners for women (50.7%). Increased smoking prevalence by occupation persisted after adjustment for age, country, and age at completion of education. Smoking was also increased among occupations with high exposure to mineral dust and gas or fumes.Conclusions:Smoking rates vary significantly by occupation. Prevention efforts in the workplace should focus on occupations with high smoking prevalence and large employment bases.
Risk factors in the onset of neck/shoulder pain in a prospective study of workers in industrial and service companies
Authors: Andersen J H , Kaergaard A , Mikkelsen S , Jensen U F , Frost P , Bonde J P , Fallentin N , Thomsen J F 
Published: August 2003

Aims:To quantify the relative contribution of work related physical factors, psychosocial workplace factors, and individual factors and aspects of somatisation to the onset of neck/shoulder pain.Methods:Four year prospective cohort study of workers from industrial and service companies in Denmark. Participants were 3123 workers, previously enrolled in a cross sectional study, where objective measurement of physical workplace factors was used. Eligible participants were followed on three subsequent occasions with approximately one year intervals. Outcomes of interest were: new onset of neck/shoulder pain (symptom cases); and neck/shoulder pain with pressure tenderness in the muscles of the neck/shoulder region (clinical cases).Results:During follow up, 636 (14.1%) participants reported neck/shoulder pain of new onset; among these, 82 (1.7%) also had clinical signs of substantial muscle tenderness. High shoulder repetition was related to being a future symptom case, and a future clinical case. Repetition was strongly intercorrelated with other physical measures. High job demands were associated with future status as a symptom case, and as a clinical case. A high level of distress predicted subsequent neck/shoulder pain, and neck/shoulder pain with pressure tenderness.Conclusions:High levels of distress, and physical and psychosocial workplace factors are predictors of onset of pain in the neck and/or shoulders, particularly pain with pressure tenderness in the muscles.
Prevalence and association of welding related systemic and respiratory symptoms in welders
Authors: El-Zein M , Malo J-L , Infante-Rivard C , Gautrin D 
Published: August 2003

Background:The prevalence of welding related respiratory symptoms coexisting with welding related systemic symptoms in welders is unknown.Aims:To determine in a sample of welders the prevalence of coexisting welding related systemic symptoms indicative of metal fume fever (MFF) and welding related respiratory symptoms suggestive of occupational asthma (OA), and the strength and significance of any association between these two groups of symptoms.Methods:A respiratory symptoms questionnaire, a systemic symptoms questionnaire, and a questionnaire on occupational history were administered by telephone to 351 of a sample of 441 welders (79.6%) from two cities in Québec, Canada.Results:The co-occurrence of possible MFF (defined as having at least two symptoms of fever, feelings of flu, general malaise, chills, dry cough, metallic taste, and shortness of breath, occurring at the beginning of the working week, 3–10 hours after exposure to welding fumes) together with welding related respiratory symptoms suggestive of OA (defined as having at least two welding related symptoms of cough, wheezing, and chest tightness) was 5.8%. These two groups of symptoms were significantly associated (χ2= 18.9, p < 0.001).Conclusion:There is a strong association between welding related MFF and welding related respiratory symptoms suggestive of OA. As such, MFF could be viewed as a pre-marker of welding related OA, a hypothesis that requires further investigation.
Increased plasma homocysteine levels in shift working bus drivers
Authors: Martins P J F , D’Almeida V , Vergani N , Perez A B A , Tufik S 
Published: August 2003

Background:Previous studies have indicated an association between shift work and cardiovascular disease. There is also considerable epidemiological evidence that hyperhomocysteinemia is an independent risk factor for cardiovascular disorders.Aims:To analyse plasma homocysteine levels in shift work bus drivers, and to investigate possible relations with sleep parameters and other biochemical factors.Methods:Blood samples were collected from 30 male shift working long-haul bus drivers in a Brazilian sample and analysed for plasma levels of homocysteine, folic acid, vitamin B12, and serum lipids. A group of 22 daytime workers, matched for age and body mass index served as controls. The incidence of mutations in the gene coding for methylene tetrahydrofolate, an enzyme which is related to hyperhomocysteinemia, was also assessed. Polysomnographic recordings were obtained from the target group.Results:Bus drivers showed significantly higher levels of plasma homocysteine than the control group (18.57v9.43 μM). Most of the other biochemical, behavioural, and molecular parameters did not differ between groups. Likewise, sleep parameters appeared to be within the normal range.Conclusions:The significantly increased plasma homocysteine levels in long-haul bus drivers did not appear to be secondary to other biochemical or behavioural problems in this group. These results suggest that hyperhomocysteinemia may be involved in the increased incidence of cardiovascular diseases observed in shift workers.
Agreement between hearing thresholds measured in non-soundproof work environments and a soundproof booth
Authors: Wong T W , Yu T S , Chen W Q , Chiu Y L , Wong C N , Wong A H S 
Published: August 2003

Aims:To study the agreement between audiometric test results measured in non-soundproof environments at the worksite, and in a soundproof booth.Methods:In a cross sectional prevalence study on noise induced hearing loss, 885 transport workers whose hearing thresholds were measured by a standard audiometric test method in non-soundproof environments at the worksite were identified to have some hearing loss (>25 dB), and were retested in a soundproof booth.Results:At 4–8 KHz, the mean of the absolute differences in hearing threshold obtained by these two methods was 2 dB or less. When the proportions of hearing loss (⩾30 dB for any frequencies at 3–8 KHz, or ⩾90 dB for three low frequencies at 0.5–2 KHz, or ⩾90 dB for three high frequencies at 3–6 KHz) were compared, considerable differences existed. A much better agreement was obtained when the criteria for hearing loss as measured in the field test under non-soundproof conditions were relaxed by 5 dB. At 4 KHz, the difference between the proportion of subjects with hearing loss as measured in the field and that as measured in the booth was the smallest. The kappa statistic was highest at 3 and 4 KHz.Conclusions:Audiometric test results conducted in non-soundproof environments in the field are comparable to those obtained in a soundproof environment among transport workers with a hearing loss of >25 dB. The hearing threshold at 4 KHz appears suitable for the estimation of the prevalence of hearing loss when appropriate adjustments are made in the diagnostic criteria.
Cancer risk for chemical workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin
Authors: Bodner K M , Collins J J , Bloemen L J , Carson M L 
Published: August 2003

Aims:To describe the long term mortality experience of a cohort of 2187 male chemical production workers previously exposed to substantial levels of dioxin.Methods:Vital status for a previously identified cohort was determined for an additional 10 years, to 1995. Dioxin exposures took place before 1983 and were sufficient to result in chloracne in 245 individuals. Mortality rates were compared with national figures and with a large pool of co-workers in unrelated production jobs.Results:All cancers combined (standardised mortality ratio (SMR) = 1.0, 95% CI 0.8 to 1.1) and lung cancer (SMR = 0.8, 95% CI 0.6 to 1.1) were at or below expected levels. Rates for soft tissue sarcoma (SMR = 2.4, 95% CI 0.3 to 8.6) and non-Hodgkin’s lymphoma (SMR = 1.4, 95% CI 0.6 to 2.7) were greater than expected overall, but below expectation in the update period. No trend of increasing risk with increasing exposure was observed for these cancers. Workers who developed chloracne had very low all-cancer rates (SMR = 0.5, 95% CI 0.3 to 1.0), and lung cancer rates (SMR = 0.3, 95% CI 0.0 to 1.1).Conclusions:We found no coherent evidence of increased cancer risk from dioxin exposure in this cohort. Our study highlights the wide range of cancer rates and the lack of consistency across dioxin studies.
Risk of soft tissue sarcomas and residence in the neighbourhood of an incinerator of industrial wastes
Authors: Comba P , Ascoli V , Belli S , Benedetti M , Gatti L , Ricci P , Tieghi A 
Published: August 2003

Aims:To investigate the association between occurrence of soft tissue sarcomas (STS) in Mantua and residence near an incinerator of industrial wastes.Methods:Cases were subjects with histologically confirmed primary malignant STS diagnosed 1989–98 in the population resident in Mantua and in the three neighbouring municipalities. Controls were randomly extracted from population registries, matched for age and sex. Residential history was reconstructed for all study subjects since 1960. Main residence was geographically positioned according to GPS standards.Results:The study included 37 STS cases (17 men and 20 women) and 171 controls. The incidence of STS in the area of study was estimated as 8.8 per 100 000 in men and 5.6 per 100 000 in women. The odds ratio associated with residence within 2 km, standardised by age and sex, was 31.4 (95% CI 5.6 to 176.1), based on five exposed cases. At greater distances, risk rapidly decreased, showing a fluctuation around the null value of 1.Conclusion:The study shows a significant increase in risk of STS associated with residence within 2 km of an industrial waste incinerator; an aetiological role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can be hypothesised.
Risk factors among elderly for short term deaths related to high levels of air pollution
Authors: Filleul L , Baldi I , Dartigues J-F , Tessier J-F 
Published: August 2003

Background:Air pollution has been linked to increased rates of mortality, but little is known about individual characteristics related to the increase in risk.Aims:To examine short term effects of air pollution on daily mortality in elderly people in Bordeaux and compare characteristics of subjects ⩾65 years old who died with levels of particulate air pollution.Methods:Daily mortality data from Bordeaux were used to determine the core model of mortality for the period 1988–97. The air pollution indicator was regressed on the core model of mortality, allowing control of the main effect modifiers and confounding factors of air pollution on the same day. The residual series of this regression model was classified from the lowest to the highest to determine “low level days” and “high level days”. A sample of 1469 elderly people in a French cohort study were studied.Results:From 1988 to 1997, 543 subjects died; 55 deaths were during days with low air pollution and 51 during days with high air pollution. Only gender differed significantly according to both types of days, with a proportion of women significantly higher in high air pollution days than men. After adjustment for smoking habits, the odds ratio was 5.2 for women.Conclusion:The risk of mortality between women and men was determined on days with “high air pollution levels” above the 50–90th centiles compared to below the 10th centile. No clear pattern was observed between days with low levels of air pollution and the different centiles of exposure.