Campylobacteriosis in returning travellers and potential secondary transmission of exotic strains.

SUMMARY: Multilocus sequence types (STs) were determined for 232 and 737 Campylobacter jejuni/coli isolates from Dutch travellers and domestically acquired cases, respectively. Putative risk factors for travel-related campylobacteriosis, and for domestically acquired campylobacteriosis caused by exotic STs (putatively carried by returning travellers), were investigated. Travelling to Asia, Africa, Latin America and the Caribbean, and Southern Europe significantly increased the risk of acquiring campylobacteriosis compared to travelling within Western Europe. Besides eating chicken, using antacids, and having chronic enteropathies, we identified eating vegetable salad outside Europe, drinking bottled water in high-risk destinations, and handling/eating undercooked pork as possible risk factors for travel-related campylobacteriosis. Factors associated with domestically acquired campylobacteriosis caused by exotic STs involved predominantly person-to-person contacts around popular holiday periods. We concluded that putative determinants of travel-related campylobacteriosis differ from those of domestically acquired infections and that returning travellers may carry several exotic strains that might subsequently spread to domestic populations even through limited person-to-person transmission.

Attribution of human Salmonella infections to animal and food sources in Italy (2002-2010): adaptations of the Dutch and modified Hald source attribution models.

The Dutch and modified Hald source attribution models were adapted to Italian Salmonella data to attribute human infections caused by the top 30 serotypes between 2002 and 2010 to four putative sources (Gallus gallus, turkeys, pigs, ruminants), at the points of animal reservoir (farm), exposure (food), and both combined. Attribution estimates were thus compared between different models, time periods and sampling points. All models identified pigs as the main source of human salmonellosis in Italy, accounting for 43-60% of infections, followed by G. gallus (18-34%). Attributions to turkeys and ruminants were minor. An increasing temporal trend in attributions to pigs and a decreasing one in those to G. gallus was also observed. Although the outcomes of the two models applied at farm and food levels essentially agree, they can be refined once more information becomes available, providing valuable insights about potential targets along the production chain.

Increased risk for Campylobacter jejuni and C. coli infection of pet origin in dog owners and evidence for genetic association between strains causing infection in humans and their pets.

We compared Campylobacter jejuni/coli multilocus sequence types (STs) from pets (dogs/cats) and their owners and investigated risk factors for pet-associated human campylobacteriosis using a combined source-attribution and case-control analysis. In total, 132/687 pet stools were Campylobacter-positive, resulting in 499 strains isolated (320 C. upsaliensis/helveticus, 100 C. jejuni, 33 C. hyointestinalis/fetus, 10 C. lari, 4 C. coli, 32 unidentified). There were 737 human and 104 pet C. jejuni/coli strains assigned to 154 and 49 STs, respectively. Dog, particularly puppy, owners were at increased risk of infection with pet-associated STs. In 2/68 cases vs. 0.134/68 expected by chance, a pet and its owner were infected with an identical ST (ST45, ST658). Although common sources of infection and directionality of transmission between pets and humans were unknown, dog ownership significantly increased the risk for pet-associated human C. jejuni/coli infection and isolation of identical strains in humans and their pets occurred significantly more often than expected.

Bayesian global regression model relating product characteristics of intermediate moisture food products to heat inactivation parameters for Salmonella Napoli and Eurotium herbariorum mould spores.

Thermal inactivation of pathogenic and spoilage organisms in low and intermediate moisture foods is of critical importance for guaranteeing microbiological safety and stability of these products. Producers tendentially reduce salt in low and intermediate moisture foods because of nutritional health considerations, but it is unclear how this affects microbial inactivation rates during pasteurization. In this study we predict the time to achieve a pre-defined 6-log reduction for Salmonella enterica subsp. enterica serovar Napoli (hereafter: S. Napoli) and Eurotium herbariorum mould spores (hereafter: E. herbariorum spores) and the relationship with product characteristics. We tested 31 design products for heat inactivation of S. Napoli and 29 design products for heat inactivation of E. herbariorum spores. We used a global Bayesian regression combining primary Weibull models with a secondary regression model to relate pasteurization temperature and product characteristics (water activity (aw), pH, and fractions of sodium chloride, sucrose and oil on product) to microbial counts. With this model, we predict the time to 6-log reduction. Thermal inactivation rates were much higher for vegetative S. Napoli than for E. herbariorum spores. Also, inactivation curves were non-linear for many experiments. There were significant associations between the Weibull model parameters and temperature, and pH and aw for S. Napoli and E. herbariorum spores, respectively. We parameterized an inactivation model for S. Napoli and E. herbariorum spores using design products with a broad range of characteristics and showed how the simplified approach of using D-values does not accurately describe the non-linearity of thermal inactivation for both types of organism. Results of our model can be used to produce accurate heat inactivation predictions as input for the pasteurization process in factories where intermediate moisture foods are manufactured.

A practical framework for the construction of a biotracing model: application to Salmonella in the pork slaughter chain.

A novel purpose of the use of mathematical models in quantitative microbial risk assessment (QMRA) is to identify the sources of microbial contamination in a food chain (i.e., biotracing). In this article we propose a framework for the construction of a biotracing model, eventually to be used in industrial food production chains where discrete numbers of products are processed that may be contaminated by a multitude of sources. The framework consists of steps in which a Monte Carlo model, simulating sequential events in the chain following a modular process risk modeling (MPRM) approach, is converted to a Bayesian belief network (BBN). The resulting model provides a probabilistic quantification of concentrations of a pathogen throughout a production chain. A BBN allows for updating the parameters of the model based on observational data, and global parameter sensitivity analysis is readily performed in a BBN. Moreover, a BBN enables "backward reasoning" when downstream data are available and is therefore a natural framework for answering biotracing questions. The proposed framework is illustrated with a biotracing model of Salmonella in the pork slaughter chain, based on a recently published Monte Carlo simulation model. This model, implemented as a BBN, describes the dynamics of Salmonella in a Dutch slaughterhouse and enables finding the source of contamination of specific carcasses at the end of the chain.

The elevated interferon gamma production is an important immunological marker in HAM/TSP pathogenesis.

Human T-lymphotropic virus type 1 (HTLV-1) is the agent of the HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), which may occur in >5% of patients during their lifetime. HTLV-1-infection causes disturbances in the immune system, and the viral load may also play an important role in the pathogenesis of HAM/TSP. Some cytokines are involved in the pathogenesis of this disorder. We have determined IL-2, IL-4, IL-10, IL-12 p70, IFN-gamma and TNF-alpha production among HTLV-1-infected subjects from our HTLV-out Clinic in Institute of Infectious 'Emílio Ribas' in Sao Paulo city, Brazil. PBMC obtained from healthy controls (n = 32), asymptomatic HTLV-1 carriers (n = 68) and HAM/TSP patients (n = 44) were grown in the absence and in the presence of phytohaemagglutinin (PHA), and the supernatants' fluids were measured for cytokines production. IL-2 levels were increased in the asymptomatic HTLV-1 carriers, and IFN-gamma was increased in both groups of patients (asymptomatic HTLV-1 carriers and more significantly among HAM/TSP patients). IL-4, IL-10, TNF-alpha and IL-12 p70 levels were not significantly increased on both groups of patients, as compared with controls. The major finding of this study is that IFN-gamma was an important cytokine for the HAM/TSP pathogenesis. Therefore, immune modulation of IFN-gamma may be critical to treat of HAM/TSP patients.

Mouse molar dentin size/shape is dependent on growth hormone status.

Growth hormone (GH) status affects dental development, but how GH influences tooth size/shape is unclear. Since GH affects dental epithelial proliferation, we hypothesized that GH influences the tooth crown and root dimensions. Dentin matrix dimensions were measured in longitudinal sections of decalcified first mandibular molars from 3 genetically modified mice: giant (GH-Excess) mice and dwarf (GH-Antagonist and GH-Receptor-Knockout) mice. GH status was found to influence crown width, root length, and dentin thickness. Analysis of these data suggests that GH influences both tooth crown and root development prior to dentinogenesis as well as during appositional growth of dentin. This is concordant with the expression of paracrine GH and GH receptors during tooth bud morphogenesis, and of GH receptors in the enamel organ, dental papilla, and Hertwig's epithelial root sheath during dentinogenesis. Based on prior studies, these GH morphogenetic actions may be mediated by the induction of both bone morphogenetic protein and insulin-like growth factor-1 expression.

Role of exercise cardiogoniometry in coronary artery disease diagnostics.

BACKGROUND: The use of noninvasive diagnostics in coronary artery disease remains underdeveloped. To date, there is no simple and inexpensive method that can lead to a reliable diagnosis. Aside from costly and elaborate imaging techniques, exercise ECG, with its rather moderate sensitivity and specificity, is the main diagnostic method available. METHODS: In this prospective study of 109 patients, the diagnostic value of cardiogoniometry (CGM), a three-dimensional, computer-analyzed vector cardiogram, was determined before and after physical stress, and the results were compared with those obtained from a stress test. We also investigated whether the sensitivity and specificity of the classical bicycle stress test could be increased with the addition of measurements obtained by CGM. Coronary angiography was used as a reference method. RESULTS: CGM had a sensitivity of 39% at rest and 42% after physical stress and a specificity of 63% at rest and 57% after stress. This method was found to be markedly inferior to pre-test probability (sensitivity 53%, specificity 81%), stress ECG (sensitivity 52%, specificity 81%), and resting ECG (sensitivity 50%, specificity 64%). The efficiency of exercise ECG testing was not improved by use of CGM results. CONCLUSION: If CGM is to be established as a viable diagnostic method in daily clinical practice, it must undergo further development.

Cognitive impairment is frequent among symptomatic carriers of human T-cell lymphotropic virus type 1 (HTLV-1), regardless of their clinical status.

The main goal of this study was to investigate the presence of cognitive impairment in patients infected with HTLV-1 presenting or not TSP/HAM. METHODS: Cross-sectional study including 104 participants: 37 asymptomatic HTLV-1 carriers, 37 patients diagnosed with TSP/HAM and 30 HTLV-1 negative control patients. Within the HTLV-1 positive group, 53 were female and 21 were male, the average age was 46 (SD=13.5) and the average schooling time was 7.7years (SD=3.3).The sociodemographic variables (genre, age and education) were compared between the three groups. The assessment tools used were: Beck Depression Inventory, Lawton's Activities of Daily Life Scale and a complete neuropsychological battery. The application of these assessment tools was carried out in blind. Both HTLV-1 asymptomatic subjects and HAM/TSP patients showed a lower performance on neuropsychological tests and higher depression scores when compared to the control group. HTLV-1 patients performed poorly in several cognitive domains, but only fluid intelligence, estimated intellectual functioning, immediate and delayed recall of visual memory and information processing speed (in the specific case of patients with TSP/HAM) reached statistical significance when compared with controls. Depression was not associated with cognitive impairment. HTLV-1 carriers presented a higher frequency of cognitive impairment than normal controls.

Ionophorous polymers. Interaction with polynucleotides and effects on RNA-directed DNA polymerase activity.

Poly(vinylbenzo-18-crown-6), a water-soluble polymer endowed with ion-binding crown moieties as pendent groups, forms insoluble complexes with polyadenylate in the presence of K+; the corresponding monomeric benzo-18-crown-6, does not form a precipitate under the same conditions. In the presence of Na+ and Mn2+ which in aqueous solution complex weakly to crown compounds, no coprecipitation of the crown polymer and polyadenylate occurs; nevertheless, the crown polymer strongly binds to immobilized polyadenylate even under these conditions. The interactions of crown polymer with the poly-nucleotide result in a loss of templating ability of the latter. Using RNA-dependent DNA polymerase of murine leukemia virus it was found that (1) enzymatic action is efficiently inhibited even in the absence of ions which coprecipitate crown polymer and template, (2) inhibition is reversed by addition of excess polynucleotide and (3) monomeric crown does not inhibit the reaction.

Effects of age, BMI, smoking and contraception on levels of Cu, Se and Zn in the blood of the population in the Czech Republic.

Variations in the levels of Cu, Se and Zn in blood were analyzed in relation to gender, age, BMI, smoking and hormonal contraception. The blood samples were collected from 3,207 blood donors (2,362 men, 845 women) during years 1996-2003. Blood concentrations of these elements were in the same range as those found for populations of other European countries. Significant differences exist between men and women, in blood concentration, for Cu (840 microg Cu.l(-1) vs. 970 microg Cu.l(-1), p<0.01) and Zn (6,780 microg Zn.l(-1) vs. 6,235 microg Zn.l(-1), p<0.01) only. The level of Cu in relation to age is increasing in men, but decreasing in women. The level of Se in relation to age increases regardless of sex. Concentrations of Zn rise with age in women group, only. Positive correlation was found between BMI and level of Cu only for group of men. For Se levels and BMI differences exist only in men namely between groups <20 and >35 (82 microg Se.l(-1) vs. 92 microg Se.l(-1)). Slight positive correlations exist between Zn concentration and BMI in women only. The significant differences were found between smokers and non-smokers for Cu in men (850 microg Cu.l(-1) vs. 830 microg Cu.l(-1)) and Se (81 microg Se.l(-1) vs. 84 microg Se.l(-1)). The smoking has not significant influence on concentration of Zn in the blood. The hormonal contraception significantly increases the concentration of Cu in blood (920 microg Cu.l(-1) vs. 1,270 microg Cu.l(-1), p<0.01). The levels of Se and Zn in blood are not influenced using hormonal contraception.

Effect of long-term administration of fluoride on the levels of EDTA-soluble protein and gamma-carboxyglutamic acid in rat incisor teeth.

EDTA-soluble material, extracted from incisor teeth of rats given 50 ppm fluoride (NaF) in drinking water ad libitum from conception to age nine wk, contained significantly higher levels of protein (P less than 0.01) and gamma-carboxyglutamic acid (P less than 0.01) than did similar material from control rats. Tooth fluoride levels indicated that the incisors were mildly fluorosed. Analysis of these data indicates that mild fluorosis of rat incisor teeth involves not only the characteristic disturbances of pigmentation and mineral structure but also some alteration of the matrix protein.

Effects of a single intravenous dose of sodium fluoride on plasma electrolytes and metabolites in rats, rabbits, and cockerels.

This study assessed the effect of a single intravenous dose of sodium fluoride (20 mg/kg body wt.) on plasma ionic fluoride and on some other plasma electrolytes and metabolites in rats, rabbits, and cockerels. At any given time following sodium fluoride administration, the plasma ionic fluoride was highest in rabbits and lowest in cockerels. The rate of removal of fluoride from plasma was slower in rabbits as compared with that in the other two species. Plasma sodium, chloride, total protein, albumin, total globulins, and osmolality were not significantly altered by sodium fluoride in any of these three species. However, plasma phosphate (inorganic), urea, creatinine, and glucose were elevated, and plasma calcium was reduced in the rats and the rabbits, but none was significantly altered in the cockerels. The analyses indicated that species variability does exist in fluoride toxicity.

Mouse cellular cementum is highly dependent on growth hormone status.

Cementum is known to be growth-hormone (GH)-responsive, but to what extent is unclear. This study examines the effects of extremes of GH status on cementogenesis in three lines of genetically modified mice; GH excess (giant), GH antagonist excess (dwarf), and GH receptor-deleted (GHR-KO) (dwarf). Age-matched mandibular molar tissues were processed for light microscope histology. Digital images of sections of first molar teeth were captured for morphometric analysis of lingual root cementum. Cross-sectional area of the cellular cementum was a sensitive guide to GH status, being reduced nearly 10-fold in GHR-KO mice, three-fold in GH antagonist mice, and increased almost two-fold in giant mice (p < 0.001). Cellular cementum length was similarly influenced by GH status, but to a lesser extent. Acellular cementum was generally unaffected. This study reveals cellular cementum to be a highly responsive GH target tissue, which may have therapeutic applications in assisting regeneration of the periodontium.

The use of YG bacterial tester strains for the monitoring of drinking water mutagenicity.

The organic extract from the 50 drinking water specimens taken in four cities were tested for mutagenicity in the Ames test (plate incorporation assay) using the parent TA98 and TA100 strains, and derived YG1041 and YG1042 strains. Four dose levels of extractable organic matter (EOM) with duplicate plate per dose were used. Slopes (revertants/mg EOM) were calculated by the Bernstein linear regression rejection model using GeneTox Manager software. The mutagenicity observed in the conventional strains TA98 and TA100 did not reach the significant increase in all tested samples with the higher mutagenic response found in TA100-S9. With the YG1041 and YG1042 tester strains, the results obtained demonstrated the clear-cut direct dose-related mutagenicity response in all tested drinking water extracts. Compared with TA98 and TA100 strains, the numbers of YG induced revertants were approximately 20 times higher. The high sensitivity of the YG tester strains could facilitate the mutagenicity monitoring in drinking water extracts, and help reduce the volume of sample required. However, to identify the chemical contaminants in drinking water responsible for the mutagenicity further studies are required.

Genotoxicity of industrial effluents, river waters, and their fractions using the Ames test and in vitro cytogenetic assay.

Total and fractionated organic extracts from industrial effluents and Labe river water were tested for mutagenicity using the Ames test with TA98 strain and its YG derivatives (YG1021, YG1024 and YG1041) and cytogenetic analysis with human peripheral lymphocytes in vitro. The bacterial mutagenicity results showed a dose-dependent increase in numbers of TA98 revertants (10(5)) with effluent extracts and lower, but still significant, increase (10(3)) with river water extracts 6 km downstream. The further increase of YG revertants indicates the possible presence of nitroarenes and aromatic amines in the tested samples. In fractionated samples the significant mutagenicity was detected in two-polar acidic and polar basic-fractions, but the numbers of revertants in all effluent fractions were about one order of magnitude lower compared with total extracts results. The cytogenetic effect in human peripheral lymphocytes in vitro was not significant. The increase in chromosomal aberrations was not clearly dose-dependent and may reflect more the combination of toxic and clastogenic effects.

Mutagenicity monitoring of airborne particulate matter (PM10) in the Czech Republic.

The mutagenic activities associated with inhalable airborne particulate matter (PM10) collected over a year in four towns (Czech Republic) have been determined. The dichloromethane extracts were tested for mutagenicity using the Ames plate incorporation test and the Kado microsuspension test both with Salmonella typhimurium TA98 and its derivative YG1041 tester strains in the presence and absence of S9 mixture. The aim of this study was to assess the suitability of both bacterial mutagenicity tests and to choose the appropriate indicator strain for monitoring purposes. To elucidate the correlation between mutagenicity and polycyclic aromatic hydrocarbons (PAHs), the concentration of PAHs in the air samples were determined by GC/MS. In general, the significant mutagenicity was obtained in organic extracts of all samples, but differences according to the method and tester strain used were observed. In both mutagenicity tests, the extractable organic mass (EOM) exhibited higher mutagenicity in the YG1041 strain (up to 97 rev/microg in the plate incorporation and 568 rev/microg in the microsuspension tests) than those in TA98 (up to 2.2 rev/microg in the plate incorporation and 14.5 rev/microg in the microsuspension tests). In the plate incorporation test, the direct mutagenic activity in YG1041 was on average 60-fold higher and in microsuspension assay 45-fold higher with respect to strain TA98. In the presence of S9 mix, the mutagenic potency in YG1041 declined (P<0.001) in summer, but increased in TA98 (P<0.05) in samples collected during the winter season. The microsuspension assay provided higher mutagenic responses in both tester strains, but in both strains a significant decrease of mutagenic potency was observed in the presence of S9 mix (P<0.001 for YG1041, P<0.05 for TA98 in winter). The mutagenic potencies detected with both indicator strains correlated well (r=0.54 to 0.87) within each mutagenicity test used but not (for TA98) or moderately (r=0.44 to 0. 66 for YG1041) between both of the tests. The mutagenic activity (in rev/m(3)) likewise the concentration of benzo[a]pyrene and sum of carcinogenic PAHs showed seasonal variation with distinctly higher values during winter season. A correlation between the PAH concentrations and the mutagenicity results for the plate incorporation, but not for the microsuspension tests was found. In samples from higher industrial areas, the higher mutagenicity values were obtained in plate incorporation test with TA98 and in both tests with YG1041 in summer season (P<0.05). According to our results, plate incorporation test seems to be more informative than microsuspension assay. For routine ambient air mutagenicity monitoring, the use of YG1041 tester strain without metabolic activation and the plate incorporation test are to be recommended.

A histochemical study of the effects of high doses of sodium fluoride on dipeptidyl peptidase II activity in the rat incisor ameloblast.

Female Wistar rats, 3 weeks old, were given sodium fluoride in saline solution (isotonic) by intraperitoneal injection at a dose of either 0, 10 or 20 mg per kg body weight. This treatment was given 9 times over 4.5 days. After fixation by perfusion and demineralization in neutral EDTA, hemi-mandibles were sectioned in a cryostat. Sections were stained for dipeptidyl peptidase II activity, using the specific substrate Lys-Ala-MNA and the coupler Fast Blue B for histochemical localization. Staining indicative of dipeptidyl peptidase II was found in the enamel organ of the incisor, particularly in cells of the stratum intermedium and in both secretory and maturation ameloblasts. This staining was markedly reduced in ameloblasts of rats given either 10 or 20 mg sodium fluoride per kg body weight.

Radiopaque acrylic resins containing miscible heavy-metal compounds.

Radiopacity is needed in order to facilitate diagnosis of polymeric appliances, which may be dislodged and become impacted in the upper respiratory or digestive tracts. In order for a stable, optically transparent, radiopaque material to be provided, heavy-metal compounds were investigated which we had previously shown to form homogeneous structures with methyl methacrylate-based systems. It was found that, when present in PMMA at 11 to 14%, several compounds of either bismuth or uranium or 35% of an organo-zirconium compound impart radiopacity equivalent to that of aluminum. A low level of cytotoxicity and lack of mutagenicity indicated that a high level of biocompatibility can be expected. Processing characteristics are somewhat altered, but formulations satisfactory for use in various dental devices were found.

Population-based biomonitoring in the Czech Republic--the system and selected results.

In the framework of the system of monitoring the environmental impact on population health, the concentration of lead, cadmium and selenium in blood and cadmium in urine was measured in adults (n = 670), children (n = 599) and umbilical blood (n = 549) using atomic absorption spectrophotometry. Furthermore, cytogenetic analysis of peripheral lymphocytes in all population groups under study was investigated. The median blood Pb level for the overall group of adults (47.8 micrograms/l, i.e. 0.23 mumol/1) was significantly higher in men (51.5 micrograms/l, i.e. 0.25 mumol/l). Smoking significantly influenced the blood Pb level in women. The 90th percentile in no group exceeded the value of 100 micrograms/l (0.48 mumol/l). The median blood Cd level in adults (0.9 microgram/l, i.e. 0.008 mumol/l) depends on smoking habit (1.25 micrograms/l, i.e. 0.01 mumol/l). The median urine Cd level was 0.585 microgram/g creatinine (0.59 mumol/mole creatinine) in adults and 0.37 microgram/g creatinine (0.37 mumol/mole creatinine) in children. The median blood Se level (53.5 micrograms/l, i.e. 0.68 mumol/l) was found to be higher in the group of non-smokers (57.5 micrograms/l, i.e 0.73 mumol/l). Lead and selenium level were significantly lower in the umbilical blood. Cytogenetic analysis results showed age-dependent average percentages of aberrant cells: 1.1% in umbilical blood, 1.27% in children and 1.71 in adults in line with the reference values for the Czech population.