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.

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.

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.

Quantifying the sources of Salmonella on dressed carcasses of pigs based on serovar distribution.

Salmonella serotyping data, qualitatively described by van Hoek et al. (2012), were used to quantify potential sources of Salmonella in a Dutch pig slaughterhouse. Statistical tests to compare per-day Salmonella prevalence and serotyping data from multiple points in the chain were used to find transmission pathways. A statistical model based on serotyping data was developed to attribute Salmonella on dressed carcasses to the most likely source. Approximately two-third of dressed carcasses carrying Salmonella on the medial surface had been contaminated by house flora. For carcasses carrying Salmonella on the distal surface, transient Salmonella from incoming pigs was a more important source. The relevance of the different sources of Salmonella varied within and between sampling days. Results were compared to those of another modeling approach, in which Salmonella concentration data from the same samples were used (Smid et al., 2012). They mostly agreed. The approach chosen by an individual slaughterhouse depends on the data that are collected.

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.

A biotracing model of Salmonella in the pork production chain.

In biotracing systems, downstream chain information and model-based approaches are used to trace the sources of microbial contamination in a food chain. This article includes the results of a biotracing model for Salmonella in the pork slaughter process chain. A Bayesian belief network model was used in which information on the Salmonella level at different locations in the slaughterhouse were used in combination with prior knowledge about the dynamics of Salmonella throughout the slaughter line. Data collected in a Dutch slaughterhouse were used to specify prior beliefs about the model inputs and to iteratively refine the distributions of the parameters in the model to obtain an optimal description of that specific slaughterhouse. The primary purpose of the model is to trace the sources of contamination for individual Salmonella-positive carcasses at the end of the slaughter line. The model results indicated that house flora on or in the carcass splitter was the source of contamination for many carcasses, especially for those that carried contamination on the cutting side. The results also indicated that the parameter values of the model may be subject to temporal variation and can be used as a tool to provide estimates of such trends. This model illustrates the concept of biotracing, gives insight into the dynamics of Salmonella in the slaughter line, and indicates the sites in the line where data collection is most effective for biotracing. This biotracing model was implemented as an interactive computer application, which is a step in the process toward an operational biotracing system by which a stakeholder can initiate immediate responses to Salmonella contamination and other hazards in the pork slaughterhouse.

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.

Strengths and weaknesses of Monte Carlo simulation models and Bayesian belief networks in microbial risk assessment.

We discuss different aspects of farm-to-fork risk assessment from a modelling perspective. Stochastic simulation models as they are presented today represent a mathematical representation of nature. In food safety risk assessment, a common modelling approach consists of a logic chain beginning at the source of the hazard and ending with the unwanted consequences of interest. This 'farm-to-fork' approach usually begins with the hazard on the farm, sometimes with different compartments presenting different parts of the production chain, and ends with the 'dose' received by the consumer or in case a dose response model is available the number of cases of illness. These models are typically implemented as Monte Carlo simulations, which are unidirectional in nature, and the link between statistics and simulation model is not interactive. A possible solution could be the use of Bayesian belief networks (BBNs) and this paper tries to discuss in an intuitive way the possibilities of using BBNs as an alternative for Monte Carlo modelling. An inventory is made of the strengths and weaknesses of both approaches, and an example is given showing an additional use of BBNs in biotracing problems.

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.

Patterns of in vitro lymphoproliferative responses among HTLV-1-infected subjects: upregulation by HTLV-1 during HIV-1 co-infection.

The present study evaluated the in vitro response to different mitogens and a candidin antigen (CMA) in Human T-cell lymphotropic virus type 1 (HTLV-1) and co-infected HIV-1/HTLV-1 patients, to identify if this co-infection may modify the spontaneous lymph proliferative response. Peripheral blood mononuclear cells from 72 healthy seronegative controls, 75 asymptomatic HTLV-1-infected carriers, 42 HAM/TSP cases, 33 solely HIV-1-infected subjects and 24 HIV-1/HTLV-1 patients were assayed in the presence and absence of mitogens (PHA, PWM and OKT3) and CMA. The HAM/TSP group had the highest proliferation rate at 3 and 6 days after culture. HAM/TSP cases showed decreased response to PHA, compared with asymptomatic HTLV-1 subjects, and most important, the co-infected HIV-1/HTLV-1 cases presented a similar response to HTLV-1-infected subjects after 3 days of culture. The singles HIV-1-infected group had decreased in vitro response. It appears that during co-infection, the HTLV-1 regulatory proteins overwhelm the action of HIV-1 regulatory proteins.

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.

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.

Incidence of dementia in a community-dwelling Brazilian population.

The authors report the incidence of dementia in a community-dwelling Brazilian population. In 1997, 1656 individuals aged 65 years or more, the majority being of very low educational level, were screened at their homes in Catanduva, Brazil, and dementia was diagnosed in 118 cases. The remaining 1538 individuals were rescreened 3.25 years later applying a health questionnaire, the Mini-Mental State Examination (MMSE) and the Pfeffer Functional Activities Questionnaire (PFAQ). According to PFAQ and MMSE scores, selected subjects were submitted to clinical, neurologic, and cognitive evaluations. The subjects diagnosed with dementia underwent laboratory tests and brain computed tomography. A total of 1119 individuals were rescreened and 50 incident cases of dementia (28 with Alzheimer disease [AD]) were identified. The incidence rate of dementia was 13.8 and of AD was 7.7 per 1000 person-years for individuals aged 65 years or older. The incidence rates of dementia almost doubled with every 5 years of age. There was no difference according to gender, but women had a higher incidence of dementia, predominantly AD, in very old age. There was a trend for higher incidence of dementia in illiterates (p = 0.07), but multivariate analysis disclosed significant association only between age and higher incidence of dementia. The incidence rates of dementia in this Brazilian community are comparable to those reported in Western and Asian studies.

Mutagenicity of airborne particulate matter PM10.

Mutagenic activity of extractable organic matter (EOM), from airborne particles collected over winters in four towns of Czech Republic, was investigated by the means of Salmonella typhimurium indicator strains TA98 and YG1041 using the Ames plate incorporation assay. Mutagenicity of all tested samples showed significant dose-related increase in number of revertants per mg of EOM. The direct mutagenic potency detected with TA98 increased further in the presence of external metabolic activation. The mutagenic potency detected with YG1041 was about two orders of magnitude higher than that detected with TA98. The mutagenicity results correlated with the concentrations of the polycyclic aromatic hydrocarbons (PAHs) determined by GC/MS. Local differences in mutagenicity, expressed as numbers of revertants per m3 of air, were observed with the highest values in Prague air samples. For routine ambient air mutagenicity monitoring, the use of YG1041 and the plate incorporation test are recommendable.

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.