Seroepidemiologic investigations of human hepatitis caused by A, B, and a possible third virus

The results of magnet implantation in the upper and lower eyelids of 29 patients suffering from Keratopathia due to lagophthalmos due to facial palsy as well as the surgical techniques involved are described. Contrary to a lateral tarsorrhaphy - still popular today - this method does not alter the form or the size of the palpebral fissure nor does it hinder the visual field. It is technically simple to perform and easily reversible should nerve function recover. The subjective results were also good.     

Anatomical distribution of heavy metals in the scallop Pecten maximus

This paper studied the anatomical distribution of mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), arsenic (As), silver (Ag), copper (Cu) and zinc (Zn) in the scallop Pecten maximus and the possible implications in terms of shellfish management. Six organs were analysed: mantle, gills, foot, digestive gland, kidney and gonad. On the basis of their anatomical distribution, two groups of metals were able to be distinguished: the first included Pb, Hg, Ni, Zn and Ag; and the second comprised the four other metals studied. The metals in the first group preferentially accumulated in the kidney (except for Pb), with generally much lower concentrations in the other organs. The metals in the second group accumulated mainly in the digestive gland. As and Cu were included in the second group, but they also had particular inter-organ distribution characteristics. Among the edible organs of the scallop only the adductor muscle contained important proportions of one metal, As (which is very likely accumulated as a non-toxic derivative). A selective evisceration of the metal rich non-edible organs may therefore be considered a reliable measure to be taken with a view to reduce the metal content of scallops used for human consumption. This could be especially relevant for Cd, which is accumulated in high concentrations in the digestive gland.     

Effects of Fat and Sugar on Dough and Biscuit Behaviours and their Relationship to Proton Mobility Characterized by TD-NMR

This study aimed to analyse the effect of large variations in fat and sucrose contents of biscuit formulation on dough rheology, biscuit quality and proton mobility. Control dough (full fat and sucrose) and 25 and 50% fat and sucrose-reduced doughs were elaborated. Rheological properties of dough were determined. Dough cooking behaviour and biscuit quality were evaluated. Fat reduction produced an increase in the consistency and elastic properties of the dough. The decrease in sucrose content affected to a lesser extent the rheological properties at room temperature, although it produced significant changes during dough baking. The biscuit quality decreased with fat and sucrose reductions. The reduction of fat or sucrose produced gluten hydration and extra interactions and subsequent cross-linking during baking, and a reduction of sucrose led to the swelling and partial gelatinization of starch during baking. A dipolar reversed eco NMR sequence was applied to determine changes in the amount and mobility of solid and mobile components both in dough and biscuits. TD-NMR results allowed corroborating the proposed hypotheses about the effects on dough and biscuit characteristics as a consequence of reduction of main ingredients, as fat and sucrose. The redistribution of water after baking can be correlated with biscuit factor and breaking force.     

Effects of dietary inclusion of sunflower soap stocks on colour,oxidation and microbiological growth of meat from light fattening lambs

Thirty-two lambs were finished on a total mixed ration (TMR) pelleted alone (00SS) or including sunflower soap stock (SS): 15SS (15 g SS per kg TMR), 30SS (30 g SS per kg TMR) and 60SS (60 g SS per kg TMR). Lambs (8 per group) were slaughtered at 27 kg live weight. Colour evolution, lipid oxidation, microbial growth and detection of diarrhoeagenic Escherichia coli were studied in meat samples. SS in the diet reduced meat lipid oxidation (P < 0.05), but had no significant effect (P > 0.05) on the cholesterol oxidation products. Meat from 60SS and control animals (00SS) revealed greater discoloration (P < 0.05) than 15SS. SS supplementation did not affect the microbiological populations, whereas high doses of SS seemed to increase the proliferation of diarrhoeagenic E. coli on day 14 (P < 0.10). These results suggest that the rate of SS inclusion in the diet of fattening lambs should not be above 15 g SS per kg TMR.     

Synergistic antimicrobial effect of lactocin AL705 and nisin combined with organic acid salts against Listeria innocua 7 in broth and a hard cheese

The effectiveness of antimicrobial mixtures against Listeria innocua 7, used as a L. monocytogenes surrogate, was investigated in broth and a food system. Synergistic effects were found for nisin (Nis), potassium sorbate (PS), calcium propionate (CP) and sodium lactate (SL), Nis + PS being the most effective binary mixture that exhibited listericidal activity in broth. To assess the effect of adding lactocin AL705 (AL705) to Nis + organic acid salt combinations, tridimensional isobolograms were generated. Sub-MIC combinations of the antimicrobials exerted bactericidal activity against L. innocua 7 after AL705 addition to the binary mixtures. However, when applied on Sardo cheese contaminated with L. innocua 7 (initial inoculum 4.45 ± 0.06 CFU g⁻¹), only Nis + PS + AL705 produced count reductions respect to the control, reaching 3.04 ± 0.35 CFU g⁻¹ counts after 15 days at 15 °C. Ternary combinations containing AL705 showed potential to reduce antimicrobial usages for L. innocua 7 inhibition.     

Phage types, virulence genes and PFGE profiles of Shiga toxin-producing Escherichia coli O157:H7 isolated from raw beef, soft cheese and vegetables in Lima (Peru)

The present study was conducted in Lima Metropolitana to evaluate the prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in raw beef, raw ground beef, soft cheese and fresh vegetables, sampled at different markets in the city. Between October 2000 and February 2001, 407 food samples were collected from different markets in the 42 districts of Lima Metropolitana. Samples were assayed for E. coli O157 by selective enrichment in modified Tryptic Soy Broth containing novobiocin, followed by immunomagnetic separation (IMS) and plating onto sorbitol MacConkey agar supplemented with cefixime and potassium tellurite. Fifty (12.3%) of 407 food samples resulted positive for E. coli O157 isolation (23 of 102 ground beef; 15 of 102 beef meat; eight of 102 soft cheese and four of 101 fresh vegetables). Thirty-five E. coli O157 isolates were further analysed for the presence of virulence genes. All 35 were positive by PCR for O157 rfbE, fliCh7, eae-gamma1 and ehxA genes. In addition, genes encoding Shiga toxins were detected in 33 of 35 isolates, five isolates (14%) encoded stx(1), stx(2), and 28 (80%) stx2 only. The isolates were of seven different phage types (PT4, PT8, PT14, PT21, PT34, PT54, and PT87) with three phage types accounting for 80% of isolates: PT4 (15 isolates), PT14 (8 isolates), and PT21 (5 isolates). Interestingly, the majority (31 of 35; 89%) of E. coli O157:H7 isolates characterized in this study belonged mainly to the phage types previously found in STEC O157:H7 strains associated with severe human disease in Europe and Canada. Pulsed-field gel electrophoresis (PFGE) of 32 isolates revealed 14 XbaI-PFGE groups (I to XIV) of similarity >85%, with 23 (72%) isolates grouped in five clusters. Some isolates from different districts presented a high clonal relatedness. Thus, PFGE group VIII clustered eleven strains from nine different districts. The broad range of PFGE subtypes found in this study demonstrates the natural occurrence of many genetic variants among STEC O157:H7 spread in Lima.     

Thermodynamic properties of multifunctional oxygenates in atmospheric aerosols from quantum mechanics and molecular dynamics: dicarboxylic acids

Ambient particulate matter contains polar multifunctional oxygenates that partition between the vapor and aerosol phases. Vapor pressure predictions are required to determine the gas-particle partitioning of such organic compounds. We present here a method based on atomistic simulations combined with the Clausius-Clapeyron equation to predict the liquid vapor pressure, enthalpies of vaporization, and heats of sublimation of atmospheric organic compounds. The resulting temperature-dependent vapor pressure equation is a function of the heat of vaporization at the normal boiling point [deltaHvap(Tb)], normal boiling point (Tb), and the change in heat capacity (liquid to gas) of the compound upon phase change [deltaCp(Tb)]. We show that heats of vaporization can be estimated from calculated cohesive energy densities (CED) of the pure compound obtained from multiple sampling molecular dynamics. The simulation method (CED) uses a generic force field (Dreiding) and molecular models with atomic charges determined from quantum mechanics. The heats of vaporization of five dicarboxylic acids [malonic (C3), succinic (C4), glutaric (C5), adipic (C6), and pimelic (C7)] are calculated at 500 K. Results are in agreement with experimental values with an averaged error of about 4%. The corresponding heats of sublimation at 298 K are also predicted using molecular simulations. Vapor pressures of the five dicarboxylic acids are also predicted using the derived Clausius-Clapeyron equation. Predicted liquid vapor pressures agree well with available literature data with an averaged error of 29%, while the predicted solid vapor pressures at ambient temperature differ considerably from a recent study by Bilde et al. (Environ. Sci. Technol. 2003, 37, 1371-1378) (an average of 70%). The difference is attributed to the linear dependence assumption thatwe used in the derived Clausius-Clapeyron equation.     

Prevalence of Escherichia coli O157 in cattle and swine in central Mexico

Escherichia coli O157:H7 is a foodborne pathogenic bacterium that can reside undetected in the gastrointestinal tract of cattle because colonization by this bacterium is asymptomatic. Recent research has indicated that swine can carry and transmit this pathogen as well. The development of more advanced and sensitive detection techniques has improved the limit of detection and increased sensitivity for this important pathogen. This study was undertaken to determine the prevalence of E. coli O157 in cattle and swine in Mexico with the more sensitive detection technique of immunomagnetic bead separation. Samples (n = 60 per farm) were taken from four cattle and four swine farms (n = 240 cattle samples, n = 240 swine samples) located throughout central Mexico in October 2001. The prevalence of E. coli O157 was found to be only 1.25% on cattle farms and 2.1% on swine farms. The prevalence in cattle in this study is lower than that reported in the United States and could be related to the lower reported prevalence of E. coli O157 in humans in Mexico. However, further research is needed to verify prevalence throughout other regions of Mexico, as well as prevalence during other seasons of the year.     

Lucerne grazing compared with concentrate-feeding slightly modifies carcase and meat quality of young bulls

Carcase and meat quality of young bulls raised on one of three fattening strategies from 224 to 450 kg were compared. One group was fed concentrates (CON), another group grazed on lucerne plus 1.8 kg DM barley/day (LUC) and the last group had the same management as LUC young bulls for 3 months and was then finished on concentrates for 2 months. Among carcase traits, only tissue composition differed, with LUC young bulls having more muscle and less subcutaneous and intermuscular fat than their counterparts. Concerning meat quality, most attributes did not differ among fattening strategies but LUC young bulls had the lowest intramuscular fat, which presented greatest n−3 PUFA content. It can be concluded that lucerne grazing can be a good alternative to concentrates for young bulls, with similar carcase and meat quality but with lower fat content and healthier fatty acid composition than young bulls fed concentrates during the finishing period.