77 resultados para Lateral pressure
Resumo:
Background: In cirrhosis, repeated flares of portal pressure and collateral blood flow provoked by postprandial hyperaemia may contribute to variceal dilation and rupture. Aim: To examine the effect of the extent of the collateral circulation on the postprandial increase in portal pressure observed in cirrhosis. Patients and methods: The hepatic venous pressure gradient (HVPG), hepatic blood flow and azygos blood flow were measured in 64 patients with cirrhosis before and after a standard liquid meal. Results: Peak increases in HVPG (median+14.9%), hepatic blood flow (median+25.4%), and azygos blood flow (median+32.2%) occurred at 30 min after the meal. Compared with patients with marked postprandial increase in HVPG (above the median, n¿=¿32), those showing mild (<15%, n¿=¿32) increase in HVPG had a higher baseline azygos flow (p<0.01) and underwent a greater postprandial increase in azygos flow (p<0.02). Hepatic blood flow increased similarly in both groups. Postprandial increases in HVPG were inversely correlated (p<0.001) with both baseline azygos flow (r¿=¿¿0.69) and its postprandial increase (r¿=¿¿0.72). Food intake increased nitric oxide products in the azygos (p<0.01), but not in the hepatic vein. Large varices (p<0.01) and previous variceal bleeding (p<0.001) were more frequent in patients with mild increase in HVPG. Conclusions: Postprandial hyperaemia simultaneously increases HVPG and collateral flow. The extent of the collateral circulation determines the HVPG response to food intake. Patients with extensive collateralisation show less pronounced postprandial increases in HVPG, but associated with marked flares in collateral flow. Collateral vessels preserve their ability to dilate in response to increased blood flow.
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The morphology and distribution of local-circuit neurons (interneurons) were examined, by calbindin D-28k and parvalbumin immunocytochemistry, in the frontal cortex (area 8) in two patients with frontal lobe dementia of non-Alzheimer type associated with classical amyotrophic lateral sclerosis (ALS), and in seven normal cases. The density of calbindin D-28k immunoreactive cells was dramatically reduced in ALS patients, but the density of parvalbumin-immunoreactive neurons was preserved. Decreased density of calbindin D-28k-immunoreactive neurons, which are mainly located in the upper cortical layers, may interfere with the normal processing of cortico-cortical connections, whereas integrity of parvalbumin-immunoreactive cells may be associated with the preservation of the major inhibitory intracortical circuits in patients with frontal lobe dementia.
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The addition of starter culture and high pressure processing after ripening improved the microbial quality of low-acid fermented sausages (fuet and chorizo). The use of Lactobacillus sakei CTC6626 and Staphylococcus xylosus CTC6013 as starter culture significantly reduced Enterobacteriaceae and Enterococcus levels in the finished sausages. Moreover, the addition of starter culture produced sausages of similar quality to traditional low-acid fermented sausages. Slightly lower pH values and higher cohesiveness were obtained for both fuet and chorizo with starter culture. Sensory analysis showed no differences between lots of chorizo whereas starter fuet was more acid and gummy. High pressure induced an additional reduction of Enterobacteriaceae in non-starter sausages. An increase of textural properties was observed after pressurization. No other differences were observed between non-treated and pressurized sausages.
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The efficiency of combining high-pressure processing (HPP) and active packaging technologies to control Listeria monocytogenes growth during the shelf life of artificially inoculated cooked ham was assessed. Three lots of cooked ham were prepared: control, packaging with alginate films, and packaging with antimicrobial alginate films containing enterocins. After packaging, half of the samples were pressurized. Sliced cooked ham stored at 6 °C experienced a quick growth of L. monocytogenes. Both antimicrobial packaging and pressurization delayed the growth of the pathogen. However, at 6 °C the combination of antimicrobial packaging and HPP was necessary to achieve a reduction of inoculated levels without recovery during 60 days of storage. Further storage at 6 °C of pressurized antimicrobial packed cooked ham resulted in L. monocytogenes levels below the detection limit (day 90). On the other hand, storage at 1 °C controlled the growth of the pathogen until day 39 in non-pressurized ham, while antimicrobial packaging and storage at 1 °C exerted a bacteriostatic effect for 60 days. All HPP lots stored at 1 °C led to counts <100 CFU/g at day 60. Similar results were observed when combining both technologies. After a cold chain break no growth of L. monocytogenes was observed in pressurized ham packed with antimicrobial films, showing the efficiency of combining both technologies.
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The effect of high pressure processing (400 MPa for 10 min) and natural antimicrobials 2 (enterocins and lactate-diacetate) on the behaviour of L. monocytogenes in sliced cooked ham 3 during refrigerated storage (1ºC and 6ºC) was assessed. The efficiency of the treatments after a 4 cold chain break was evaluated. Lactate-diacetate exerted a bacteriostatic effect against L. 5 monocytogenes during the whole storage period (3 months) at 1ºC and 6ºC, even after 6 temperature abuse. The combination of low storage temperature (1ºC), high pressure 7 processing (HPP) and addition of lactate-diacetate reduced the levels of L. monocytogenes 8 during storage by 2.7 log CFU/g. The most effective treatment was the combination of HPP, 9 enterocins and refrigeration at 1ºC, which reduced the population of the pathogen to final counts 10 of 4 MPN/g after 3 months of storage, even after the cold chain break.
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The combined effect of pressure and mild temperature treatments on bovine sarcoplasmic proteins and quality parameters was assessed. M. longissimus dorsi samples were pressurised in a range of 200–600 MPa and 10–30 °C. High Pressure Processing (HPP) induced a reduction of protein solubility (p < 0.001) compared to non-treated controls (NT), more pronounced above 200 MPa. HPP at pressures higher than 200 MPa induced a strong modification (p < 0.001) of meat colour and a reduction of water holding capacity (WHC). SDS–PAGE analysis demonstrated that HPP significantly modified the composition of the sarcoplasmic protein fraction. The pressurisation temperature mainly affected protein solubility and colour; a smaller effect was observed on protein profiles. Significant correlations (p < 0.001) between sarcoplasmic protein solubility and both expressible moisture (r = −0.78) and colour parameters (r = −0.81 to −0.91) suggest that pressure induced denaturation of sarcoplasmic proteins could influence to some extent WHC and colour modifications of beef. Changes in protein band intensities were also significantly correlated with protein solubility, meat lightness and expressible moisture. These results describe the changes induced by HPP on sarcoplasmic proteins and confirm a relationship between modification of the sarcoplasmic protein fraction and alteration of meat quality characteristics
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Listeria monocytogenes was inoculated on the surface of sliced fermented sausages with no added sodium salt. The pathogen was progressively inactivated during the product shelf life (90 days). Antimicrobial packaging of fermented sausages with PVOH films containing nisin induced a more pronounced reduction of L. monocytogenes counts during refrigerated storage. HPP alone (600 MPa, 5 min, 12 °C) had no antimicrobial effect against L. monocytogenes at the studied conditions. Combination of HPP with antimicrobial packaging did not produce any extra protection against L. monocytogenes compared to antimicrobial packaging alone. The lack of effect of HPP on L. monocytogenes was attributed to a protective effect exerted by the low water activity of the product and its lactate content. These results reflect that antimicrobial packaging with the inclusion of nisin as a natural antimicrobial could be considered as an effective method to reduce the levels of L. monocytogenes in sliced fermented sausages with no added sodium salt
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The aim of this research was to investigate the effects of high pressure processing (HPP) on consumer acceptance for chilled ready meals manufactured using a low-value beef cut. Three hundred consumers evaluated chilled ready meals subjected to 4 pressure treatments and a non-treated control monadically on a 9-point scale for liking for beef tenderness and juiciness, overall flavour, overall liking, and purchase intent. Data were also collected on consumers' food consumption patterns, their attitudes towards food by means of the reduced food-related lifestyle (FRL) instrument, and socio-demographics. The results indicated that a pressure treatment of 200 MPa was acceptable to most consumers. K-means cluster analysis identified 4 consumer groups with similar preferences, and the optimal pressure treatments acceptable to specific consumer groups were identified for those firms that would wish to target attitudinally differentiated consumer segments
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Aeromonas hydrophila AH-3 lateral flagella are not assembled when bacteria grow in liquid media; however, lateral flagellar genes are transcribed. Our results indicate that A. hydrophila lateral flagellar genes are transcribed at three levels (class I to III genes) and share some similarities with, but have many important differences from, genes of Vibrio parahaemolyticus. A. hydrophila lateral flagellum class I gene transcription is σ70 dependent, which is consistent with the fact that lateral flagellum is constitutively transcribed, in contrast to the characteristics of V. parahaemolyticus. The fact that multiple genes are included in class I highlights that lateral flagellar genes are less hierarchically transcribed than polar flagellum genes. The A. hydrophila lafK-fliEJL gene cluster (where the subscript L distinguishes genes for lateral flagella from those for polar flagella) is exclusively from class I and is in V. parahaemolyticus class I and II. Furthermore, the A. hydrophila flgAMNL cluster is not transcribed from the σ54/LafK-dependent promoter and does not contain class II genes. Here, we propose a gene transcriptional hierarchy for the A. hydrophila lateral flagella.
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Death of sensory hair cells in the inner ear results in two global health problems that millions of people around the world suffer: hearing loss and balance disorders. Hair cells convert sound vibrations and head movements into electrical signals that are conveyed to the brain, and as a result of aging, exposure to noise, modern drugs or genetic predisposition, hair cells die. In mammals, the great majority of hair cells are produced during embryogenesis, and hair cells that are lost after birth are not replaceable. However, in the last decades, researches have shown some model organisms that retain the ability to regenerate hair cells damaged after embryogenesis, such as Zebrafish and chicken, providing clues as to the cellular and molecular mechanisms that may block hair cell regeneration in mammals. This discovery initiated a search for methods to stimulate regeneration or replacement of hair cells in mammals, a search that, if fruitful, will revolutionize the treatment of hearing loss and balance disorders. One aim of my project is to study the role of retinoic acid in adult Zebrafish and in mice, which is a metabolite of vitamin A known as an essential molecule to activate hair cell regeneration after cells damaged in Zebrafish embryo. We want to study important genes involved in retinoic acid pathway, such as Aldh1a3 and RARs genes, to check what their role is in the inner ear of adult Zebrafish and compare result obtained in the inner ear of mice. On the other hand, Zebrafish lateral line contains neuromast, which are formed by the same structure than the inner ear: hair cells surrounded by supporting cells and neurons. The lateral line is a structure below the skin's surface that makes easier to damage hair cells to study their regeneration. For that reason, another aim of my project is to study how Sox2 and Atoh1, essential genes during the inner ear development, change their expression during hair cell regeneration in the lateral line. In my project, the most important concepts related to Zebrafish world are explained in order to understand why we have studied this animal and these essential genes. Then, techniques that we used are explained, with their protocol attached in the annexes. Finally, results of my project are shown, but many of them were not expected and they would be needed to follow studying.
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The aim of this study was to investigate the effect of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on key physical and chemical characteristics of white cabbage (Brassica oleracea L. var. capitata alba). Thermal treatment (blanching) was also investigated and compared with high-pressure processing (HPP). HPP at 400 MPa and 20–40 °C caused significantly larger colour changes compared to any other pressure or thermal treatment. All pressure treatments induced a softening effect, whereas blanching did not significantly alter texture. Both blanching and pressure treatments resulted in a reduction in the levels of ascorbic acid, effect that was less pronounced for blanching and HPP at 600 MPa and 20–40 °C. HPP at 600 MPa resulted in significantly higher total phenol content, total antioxidant capacity and total isothiocyanate content compared to blanching. In summary, the colour and texture of white cabbage were better preserved by blanching. However, HPP at 600 MPa resulted in significantly higher levels of phytochemical compounds. The results of this study suggest that HPP may represent an attractive technology to process vegetable-based food products that better maintains important aspects related to the content of health-promoting compounds. This may be of particular relevance to the food industry sector involved in the development of convenient novel food products with excellent functional properties
Resumo:
The effects of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on the physical and nutritional properties of swede roots (Brassica napus var. napobrassica) were assessed. Changes induced by high pressure processing (HPP) on the original properties of swede samples were compared with those produced by thermal treatment (blanching). All studied treatments altered the physical properties of swede, resulting in a loss of hardness and water binding capacity. The strongest alteration of texture was observed after HPP at 400 MPa, while 600 MPa was the treatment that better preserved the texture properties of swede. Blanching caused less total colour changes (ΔE) than HPP. Antioxidant properties of swede were measured as total antioxidant capacity, ascorbic acid and total phenol content. All treatments caused a loss of antioxidant capacity, which was less pronounced after HPP at 600 MPa and 20 °C and blanching. Four glucosinolates were detected in swede roots, glucoraphanin, progoitrin, glucobrassicanapin and glucobrassicin. Glucobrassicanapin and glucobrassicin contents were reduced with all studied treatments. Progoitrin content was not affected by blanching and HPP at 200 MPa. HPP at higher pressure levels (400 and 600 MPa), though, induced an increase of progoitrin levels. The results indicated that blanching and HPP at 600 MPa and 20 °C were the treatments that better preserved the original quality properties of swede.
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The relationship between pressure induced changes on individual proteins and selected quality parameters in bovine longissimus thoracis et lumborum (LTL) muscle was studied. Pressures ranging from 200 to 600 MPa at 20 °C were used. High pressure processing (HPP) at pressures above 200 MPa induced strong modifications of protein solubility, meat colour and water holding capacity (WHC). The protein profiles of non-treated and pressure treated meat were observed using two dimensional electrophoresis. Proteins showing significant differences in abundance among treatments were identified by mass spectrometry. Pressure levels above 200 MPa strongly modified bovine LTL proteome with main effects being insolubilisation of sarcoplasmic proteins and solubilisation of myofibrillar proteins. Sarcoplasmic proteins were more susceptible to HPP effects than myofibrillar. Individual protein changes were significantly correlated with protein solubility, L*, b* and WHC, providing further insights into the mechanistic processes underlying HPP influence on quality and providing the basis for the future development of protein markers to assess the quality of processed meats.
Resumo:
Etimológicamente, esclerosis significa endurecimiento (skerós es "endurecmiento patológico" y osis, "enfermedad") y hace referencia al estado de la médula espinal en las fases avanzadas de la enfermedad. Lateral significa "al lado" y pone de manifiesto la ubicación del daño en la médula espinal. Por último, el término amiotrófica significa "sin nutrición muscular" y se refiere a la pérdida de señales que los nervios envían normalmente a los músculos. La Esclerosis Lateral Amiotrófica (ELA) es la enfermedad más grave de un grupo de dolencias que tienen síntomas similares y son conocidas como "enfermedades de motoneuronas": la Atrofia Muscular Juvenil o Enfermedad de Kugelberg Welander, la Atrofia Muscular Infantil o Enfermedad de Werdnig Hoffmann, la parálisis bulbar progresiva, la amiotrofia focal benigna, la esclerosis lateral primaria y la atrofia muscular espinobulbar o Enfermedad de Kennedy.