Evaluation of the use of probiotic acid lactic bacteria in the development of chicken hambúrguer

The objective of this study was to investigate the effect of fermentation with Lactobacillus acidophilus CRL 1014 on the physicochemical, microbiological and sensory characteristics of a hamburger product like processed with chicken meat and okara flour, with reduction of curing salts. A mixture of ingredients containing 90% chicken meat and 10% okara flour was subjected to the following treatments: F1: fermented with Lactobacillus acidophilus; F2:75 mg nitrite/kg and fermented with Lactobacillus acidophilus; F3: 150 mg nitrite/kg and unfermented. The quality of the “hamburgers” was assessed by physical and chemical analysis (pH, cooking yield and shrinkage), chemical composition, microbiological tests (Salmonella spp., count of sulphite-reducing clostridia, staphylococos coagulase-positive, total coliforms and Escherichia coli) and sensory analysis (sensory acceptance and purchase intent). During the first six days of fermentation, there was a decrease in pH from approximately 6.33 to 5.10. All the samples showed the same chemical composition (p < 0.05). The fermentation process was observed to inhibit the multiplication of microorganisms of several groups: coagulasepositive staphylococci, sulphite-reducing clostridia, Salmonella spp. and E. coli. The different “hamburgers” formulations showed high scores for all the sensory attributes evaluated, without differing from each other (p < 0.05). The results showed that the use of L. acidophilus CRL 1014 enabled the production of a safe product, with good physicochemical and sensory characteristics, in the absence of curing salts.

Acidose láctica ruminal aguda induzida experimentalmente em ovinos: estudo clínico e laboratorial

Pós-graduação em Medicina Veterinária - FCAV

Distinct mechanisms underlie adaptation of proximal tubule Na+/H+ exchanger isoform 3 in response to chronic metabolic and respiratory acidosis

The Na+/H+ exchanger isoform 3 (NHE3) is essential for HCO3- reabsorption in renal proximal tubules. The expression and function of NHE3 must adapt to acid-base conditions. The goal of this study was to elucidate the mechanisms responsible for higher proton secretion in proximal tubules during acidosis and to evaluate whether there are differences between metabolic and respiratory acidosis with regard to NHE3 modulation and, if so, to identify the relevant parameters that may trigger these distinct adaptive responses. We achieved metabolic acidosis by lowering HCO3- concentration in the cell culture medium and respiratory acidosis by increasing CO2 tension in the incubator chamber. We found that cell-surface NHE3 expression was increased in response to both forms of acidosis. Mild (pH 7.21 +/- 0.02) and severe (6.95 +/- 0.07) metabolic acidosis increased mRNA levels, at least in part due to up-regulation of transcription, whilst mild (7.11 +/- 0.03) and severe (6.86 +/- 0.01) respiratory acidosis did not up-regulate NHE3 expression. Analyses of the Nhe3 promoter region suggested that the regulatory elements sensitive to metabolic acidosis are located between -466 and -153 bp, where two consensus binding sites for SP1, a transcription factor up-regulated in metabolic acidosis, were localised. We conclude that metabolic acidosis induces Nhe3 promoter activation, which results in higher mRNA and total protein level. At the plasma membrane surface, NHE3 expression was increased in metabolic and respiratory acidosis alike, suggesting that low pH is responsible for NHE3 displacement to the cell surface.

In vitro and in vivo evaluation of the biocompatibility of a calcium phosphate/poly(lactic-co-glycolic acid) composite

This study assess the effects of bioceramic and poly(lactic-co-glycolic acid) composite (BCP/PLGA) on the viability of cultured macrophages and human dental pulp fibroblasts, and we sought to elucidate the temporal profile of the reaction of pulp capping with a composite of bioceramic of calcium phosphate and biodegradable polymer in the progression of delayed dentine bridge after (30 and 60 days) in vivo. Histological evaluation of inflammatory infiltrate and dentin bridge formation were performed after 30 and 60 days. There was similar progressive fibroblast growth in all groups and the macrophages showed viability. The in vivo study showed that of the three experimental groups: BCP/PLGA composite, BCP and calcium hydroxide (Ca(OH)(2)) dentin bridging was the most prevalent (90 %) in the BCP/PLGA composite after 30 days, mild to moderate inflammatory response was present throughout the pulp after 30 days. After 60 days was observed dentine bridging in 60 % and necrosis in 40 %, in both groups. The results indicate that understanding BCP/PLGA composite is biocompatible and by the best tissue response as compared to calcium hydroxide in direct pulp capping may be important in the mechanism of delayed dentine bridge after 30 and 60 days.

Gas-producing and spoilage potential of Enterobacteriaceae and lactic acid bacteria isolated from chilled vacuum-packaged beef

This study aimed to enumerate and identify lactic acid bacteria and Enterobacteriaceae from spoiled and nonspoiled chilled vacuum-packaged beef and determine their potential to cause blown pack spoilage. These microbial groups were also enumerated in nonspoiled samples and detected in abattoir samples. The potential of isolates to cause blown pack spoilage of vacuum-packaged beef stored at chilled temperature (4 degrees C) and abuse temperature (15 degrees C) was investigated. Populations of lactic acid bacteria in exudate of spoiled and nonspoiled samples were not significantly different (P > 0.05), whereas the number of lactic acid bacteria on the surface was significantly higher (P < 0.05) in spoiled samples as compared to nonspoiled samples. The population of Enterobacteriaceae species in exudate and on the surface of samples were significantly higher (P < 0.05) in spoiled packs in comparison with nonspoiled packs. Results of the deterioration potential showed that blown pack spoilage was noticeable after 7 days at 15 degrees C and after 6 weeks at 4 degrees C for samples inoculated with Hafnia alvei.

Intravenous Hypertonic Saline Solution (7.5%) and Oral Electrolytes to Treat of Calves with Noninfectious Diarrhea and Metabolic Acidosis

Objective The aim of this study was to compare the efficacy of treating osmotic diarrhea and dehydration in calves with hypertonic saline solution (HSS) IV, isotonic electrolyte solution (IES) PO, and a combination of these 2 solutions (HSS + IES). Experimental Design Eighteen male calves 830 days of age were used to evaluate the efficacy of 3 methods of fluid therapy after induction of osmotic diarrhea and dehydration. The diarrhea and dehydration were induced by administration of saccharose, spironolactone, and hydrochlorothiazide for 48 hours. The animals were randomly divided into 3 experimental groups: Group 1: 7.2% hypertonic saline solution-HSS (5 mL/kg IV); Group 2: oral isotonic electrolyte solution IES (60 mL/kg PO); or Group 3: HSS+IES. Clinical signs and laboratory finding observed 48 hours post-induction (Time 0) included diarrhea, dehydration, lethargy, and metabolic acidosis. Results Calves treated with HSS + IES experienced decreases in hematocrit, total protein concentration, albumin concentration, urea nitrogen concentration, and plasma volume as well as increases in blood pH, blood bicarbonate concentration, and central venous pressure between 1 and 3 hours post-treatment. These findings also were observed in animals treated with IES, however, at a slower rate than in the HSS + IES-treated animals. Animals treated with HSS continued to display signs of dehydration, lethargy, and metabolic acidosis 24 hours post-treatment. Conclusion Treatment with a combination of HSS and IES produced rapid and sustainable correction of hypovolemia and metabolic acidosis in calves with noninfections diarrhea and dehydration.

Multi-Walled Carbon Nanotubes and Poly(lactic acid) Nanocomposite Fibrous Membranes Prepared by Solution Blow Spinning

Nanocomposite fibers based on multi-walled carbon nanotubes (MWCNT) and poly(lactic acid) (PLA) were prepared by solution blow spinning (SBS). Fiber morphology was characterized by scanning electron microscopy (SEM) and optical microscopy (OM). Electrical, thermal, surface and crystalline properties of the spun fibers were evaluated, respectively, by conductivity measurements (4-point probe), thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), contact angle and X-ray diffraction (XRD). OM analysis of the spun mats showed a poor dispersion of MWCNT in the matrix, however dispersion in solution was increased during spinning where droplets of PLA in solution loaded with MWCNT were pulled by the pressure drop at the nozzle, producing PLA fibers filled with MWCNT. Good electrical conductivity and hydrophobicity can be achieved at low carbon nanotube contents. When only 1 wt% MWCNT was added to low-crystalline PLA, surface conductivity of the composites increased from 5 x 10(-8) to 0.46 S/cm. Addition of MWCNT can slightly influence the degree of crystallinity of PLA fibers as studied by XRD and DSC. Thermogravimetric analyses showed that MWCNT loading can decrease the onset degradation temperature of the composites which was attributed to the catalytic effect of metallic residues in MWCNT. Moreover, it was demonstrated that hydrophilicity slightly increased with an increase in MWCNT content. These results show that solution blow spinning can also be used to produce nanocomposite fibers with many potential applications such as in sensors and biosensors.

Use of sub-lethal high pressure homogenization (HPH) treatments to enhance functional properties of lactic acid bacteria probiotic strains

The aim of this PhD thesis was to evaluate the effect of a sub-lethal HPH treatment on some probiotic properties and on cell response mechanisms of already-known functional strains, isolated from Argentinean dairy products. The results achieved showed that HPH treatments, performed at a sub-lethal level of 50 MPa, increased some important functional and technological characteristics of the considered non intestinal probiotic strains. In particular, HPH could modify cell hydrophobicity, autoaggregation and resistance to acid gastric conditions (tested in in vitro model), cell viability and cell production of positive aroma compounds, during a refrigerate storage in a simulated dairy product. In addition, HPH process was able to increase also some probiotic properties exerted in vivo and tested for two of the considered strains. In fact, HPH-treated cells were able to enhance the number of IgA+ cells more than other not treated cells, although this capacity was time dependent. On the other hand, HPH treatment was able to modify some important characteristics that are linked to the cell wall and, consequently, could alter the adhesion capacity in vivo and the interaction with the intestinal cells. These modifications, involving cell outermost structures, were highlighted also by Trasmission Electron Microscopy (TEM) analysis. In fact, the micrographs obtained showed a significant effect of the pressure treatment on the cell morphology and particularly on the cell wall. Moreover, the results achieved showed that composition of plasma membranes and their level of unsaturation are involved in response mechanisms adopted by cells exposed to the sub-lethal HPH treatment. Although the response to the treatment varied according to the characteristics of individual strains, time of storage and suspension media employed, the results of present study, could be exploited to enhance the quality of functional products and to improve their organoleptic properties.

Prevalence and densitometric characteristics of incomplete distal renal tubular acidosis in men with recurrent calcium nephrolithiasis

The aim of this study was to assess the prevalence of incomplete distal renal tubular acidosis (idRTA) in men with recurrent calcium nephrolithiasis and its potential impact on bone mineral density. We conducted a retrospective analysis of 150 consecutive, male idiopathic recurrent calcium stone formers (RCSFs), which had originally been referred to the tertiary care stone center of the University Hospital of Berne for further metabolic evaluation. All RCSFs had been maintained on a free-choice diet while collecting two 24-h urine samples and delivered second morning urine samples after 12 h fasting. Among 12 RCSFs with a fasting urine pH >5.8, a modified 3-day ammonium chloride loading test identified idRTA in 10 patients (urine pH >5.32, idRTA group). We matched to each idRTA subject 5 control subjects from the 150 RCSFs, primary by BMI and then by age, i.e., 50 patients, without any acidification defect (non-RTA group) for comparative biochemistry and dual energy X-ray absorptiometry (DEXA) analyses. The prevalence of primary idRTA among RCSFs was 6.7% (10/150). Patients with idRTA had significantly higher 2-h fasting and 24-h urine pH (2-h urine pH: 6.6 ± 0.4 vs. 5.2 ± 0.1, p = 0.001; 24-h urine pH: 6.1 ± 0.2 vs. 5.3 ± 0.3, p = 0.001), 24-h urinary calcium excretion (7.70 ± 1.75 vs. 5.69 ± 1.73 mmol/d, p = 0.02), but significantly lower 24-h urinary urea excretion (323 ± 53 vs. 399 ± 114 mmol/d, p = 0.01), urinary citrate levels (2.32 ± 0.82 vs. 3.01 ± 0.72 mmol/d, p = 0.04) and renal phosphate threshold normalized for the glomerular filtration rate (TmPO(4)/GFR: 0.66 ± 0.17 vs. 0.82 ± 0.21, p = 0.03) compared to non-RTA patients. No significant difference in bone mineral density (BMD) was found between idRTA and non-RTA patients for the lumbar spine (LS BMD (g/cm(2)): 1.046 ± 0.245 SD vs. 1.005 ± 0.119 SD, p = 0.42) or femoral neck (FN BMD (g/cm(2)): 0.830 ± 0.135 SD vs. 0.852 ± 0.127 SD). Thus, idRTA occurs in 1 in 15 male RCSFs and should be sought in all recurrent calcium nephrolithiasis patients. Bone mineral density, however, does not appear to be significantly affected by idRTA.

UPLC-MS-based urine metabolomics reveals indole-3-lactic acid and phenyllactic acid as conserved biomarkers for alcohol-induced liver disease in the Ppara-null mouse model

Since the development and prognosis of alcohol-induced liver disease (ALD) vary significantly with genetic background, identification of a genetic background-independent noninvasive ALD biomarker would significantly improve screening and diagnosis. This study explored the effect of genetic background on the ALD-associated urinary metabolome using the Ppara-null mouse model on two different backgrounds, C57BL/6 (B6) and 129/SvJ (129S), along with their wild-type counterparts. Reversed-phase gradient UPLC-ESI-QTOF-MS analysis revealed that urinary excretion of a number of metabolites, such as ethylsulfate, 4-hydroxyphenylacetic acid, 4-hydroxyphenylacetic acid sulfate, adipic acid, pimelic acid, xanthurenic acid, and taurine, were background-dependent. Elevation of ethyl-β-d-glucuronide and N-acetylglycine was found to be a common signature of the metabolomic response to alcohol exposure in wild-type as well as in Ppara-null mice of both strains. However, increased excretion of indole-3-lactic acid and phenyllactic acid was found to be a conserved feature exclusively associated with the alcohol-treated Ppara-null mouse on both backgrounds that develop liver pathologies similar to the early stages of human ALD. These markers reflected the biochemical events associated with early stages of ALD pathogenesis. The results suggest that indole-3-lactic acid and phenyllactic acid are potential candidates for conserved and pathology-specific high-throughput noninvasive biomarkers for early stages of ALD.

Effect Of Confined Impinging Jet Mixing Processing Parameters On Poly (Lactic Acid) Nanoparticle Morphology

Biodegradable nanoparticles are at the forefront of drug delivery research as they provide numerous advantages over traditional drug delivery methods. An important factor affecting the ability of nanoparticles to circulate within the blood stream and interact with cells is their morphology. In this study a novel processing method, confined impinging jet mixing, was used to form poly (lactic acid) nanoparticles through a solvent-diffusion process with Pluronic F-127 being used as a stabilizing agent. This study focused on the effects of Reynolds number (flow rate), surfactant presence in mixing, and polymer concentration on the morphology of poly (lactic acid) nanoparticles. In addition to looking at the parameters affecting poly (lactic acid) morphology, this study attempted to improve nanoparticle isolation and purification methods to increase nanoparticle yield and ensure specific morphologies were not being excluded during isolation and purification. The isolation and purification methods used in this study were centrifugation and a stir cell. This study successfully produced particles having pyramidal and cubic morphologies. Despite successful production of these morphologies the yield of non-spherical particles was very low, additionally great variability existed between redundant trails. Surfactant was determined to be very important for the stabilization of nanoparticles in solution but appears to be unnecessary for the formation of nanoparticles. Isolation and purification methods that produce a high yield of surfactant free particles have still not been perfected and additional testing will be necessary for improvement.¿

Early resuscitation with polymerized bovine hemoglobin reverses acidosis, but not peripheral tissue oxygenation, in a severe hamster shock model

Awake hamsters equipped with the dorsal window chamber preparation were subjected to hemorrhage of 50% of the estimated blood volume. Initial resuscitation (25% of estimated blood volume) with polymerized bovine hemoglobin (PBH) or 10% hydroxyethyl starch (HES) occurred in concert with an equivolumetric bleeding to simulate the early, prehospital setting (exchange transfusion). Resuscitation (25% of estimated blood volume) without bleeding was performed with PBH, HES, or autologous red blood cells (HES-RBCs). Peripheral microcirculation, tissue oxygenation, and systemic hemodynamic and blood gas parameters were assessed. After exchange transfusion, base deficit was -8.6 +/- 3.7 mmol/L (PBH) and -5.1 +/- 5.3 mmol/L (HES) (not significant). Functional capillary density was 17% +/- 6% of baseline (PBH) and 31% +/- 11% (HES) (P < 0.05) and arteriolar diameter 73% +/- 3% of baseline (PBH) and 90% + 5% (HES) (P < 0.01). At the end, hemoglobin levels were 3.7 +/- 0.3 g/dL with HES, 8.2 +/- 0.6 g/dL with PBH, and 10.4 +/- 0.8 g/dL with HES-RBCs (P < 0.01 HES vs. PBH and HES-RBCs, P < 0.05 PBH vs. HES-RBCs). Base excess was restored to baseline with PBH and HES-RBCs, but not with HES (P < 0.05). Functional capillary density was 46% +/- 5% of baseline (PBH), 62% + 20% (HES-RBCs), and 36% +/- 19% (HES) (P < 0.01 HES-RBCs vs. HES). Peripheral oxygen delivery and consumption was highest with HES-RBCs, followed by PBH (P < 0.05 HES-RBCs vs. PBH, P < 0.01 HES-RBCs and PBH vs. HES). In conclusion, the PBH led to a correction of base deficit comparable to blood transfusion. However, oxygenation of the peripheral tissue was inferior with PBH. This was attributed to its negative impact on the peripheral microcirculation caused by arteriolar vasoconstriction.