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Intermediate Production (intermediate + production)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Bile acid treatment alters hepatic disease and bile acid transport in peroxisome-deficient PEX2 Zellweger mice,

HEPATOLOGY, Issue 4 2007
Megan H. Keane
The marked deficiency of peroxisomal organelle assembly in the PEX2,/, mouse model for Zellweger syndrome provides a unique opportunity to developmentally and biochemically characterize hepatic disease progression and bile acid products. The postnatal survival of homozygous mutants enabled us to evaluate the response to bile acid replenishment in this disease state. PEX2 mutant liver has severe but transient intrahepatic cholestasis that abates in the early postnatal period and progresses to steatohepatitis by postnatal day 36. We confirmed the expected reduction of mature C24 bile acids, accumulation of C27,bile acid intermediates, and low total bile acid level in liver and bile from these mutant mice. Treating the PEX2,/, mice with bile acids prolonged postnatal survival, alleviated intrahepatic cholestasis and intestinal malabsorption, reduced C27,bile acid intermediate production, and prevented older mutants from developing severe steatohepatitis. However, this therapy exacerbated the degree of hepatic steatosis and worsened the already severe mitochondrial and cellular damage in peroxisome-deficient liver. Both untreated and bile acid,fed PEX2,/, mice accumulated high levels of predominantly unconjugated bile acids in plasma because of altered expression of hepatocyte bile acid transporters. Significant amounts of unconjugated bile acids were also found in the liver and bile of PEX2 mutants, indicating a generalized defect in bile acid conjugation. Conclusion: Peroxisome deficiency widely disturbs bile acid homeostasis and hepatic functioning in mice, and the high sensitivity of the peroxisome-deficient liver to bile acid toxicity limits the effectiveness of bile acid therapy for preventing hepatic disease. (HEPATOLOGY 2007;45:982,997.) [source]

Understanding hydrological processes with scarce data in a mountain environment

HYDROLOGICAL PROCESSES, Issue 12 2008
A. Chaponnière
Abstract Performance of process-based hydrological models is usually assessed through comparison between simulated and measured streamflow. Although necessary, this analysis is not sufficient to estimate the quality and realism of the modelling since streamflow integrates all processes of the water cycle, including intermediate production or redistribution processes such as snowmelt or groundwater flow. Assessing the performance of hydrological models in simulating accurately intermediate processes is often difficult and requires heavy experimental investments. In this study, conceptual hydrological modelling (using SWAT) of a semi-arid mountainous watershed in the High Atlas in Morocco is attempted. Our objective is to analyse whether good intermediate processes simulation is reached when global-satisfying streamflow simulation is possible. First, parameters presenting intercorrelation issues are identified: from the soil, the groundwater and, to a lesser extent, from the snow. Second, methodologies are developed to retrieve information from accessible intermediate hydrological processes. A geochemical method is used to quantify the contribution of a superficial and a deep reservoir to streamflow. It is shown that, for this specific process, the model formalism is not adapted to our study area and thus leads to poor simulation results. A remote-sensing methodology is proposed to retrieve the snow surfaces. Comparison with the simulation shows that this process can be satisfyingly simulated by the model. The multidisciplinary approach adopted in this study, although supported by the hydrological community, is still uncommon. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Analysis of cytokine genes polymorphism as markers for inhibitor development in haemophilia A

INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2010
D. Chaves
Summary Antibodies that block factor VIII (FVIII) activity appear in some haemophilia A patients treated with FVIII replacement therapy and severely impaired treatment. To date, the mechanisms that lead to this immune response are unknown. In this work, haplotypes of cytokine interleukin 10 (IL-10) gene have been associated with the presence of FVIII inhibitors in a group of Brazilian haemophilia A patients. The coexistence of a haplotype defining high IL-10 synthesis and one defining an intermediate production of cytokines is found to be associated with the group of patients who have a history of inhibitor development. Additionally, the coexistence of haplotypes defining high and low IL-10 syntheses is strongly associated with the group of negative inhibitors. These results have shown that the simple association considering only the presence or the absence of a haplotype and the development of inhibitors in haemophilia A is not sufficient. Data obtained in this work sustain the idea that the genetic studies may partly explain why only approximately 25% of haemophilia A patients develop FVIII inhibitors. Other genetic issues and details of the protein replacement therapy should be considered to measure the chances of a patient to develop anti-FVIII antibodies. [source]

Comparative study of the intracellular superoxide anion production in different penaeid species through the NBT-reduction assay

AQUACULTURE RESEARCH, Issue 7 2010
Cristhiane Guertler
Abstract The capacity of reactive oxygen intermediates production upon haemocyte stimulation is one of the most important immunoparameter utilized to assess the health status in cultivated shrimps. In the present study, we compared oxidative stress potential, by measuring the superoxide anion production in three penaeid shrimps: two wild Atlantic species, the pink shrimp Farfantepenaeus paulensis and the white shrimp Litopenaeus schmitti and one cultivated Pacific species, the white shrimp, Litopenaeus vannamei, through the nitro-blue-tetrazolium-reduction assay. We also proposed an optimized experimental protocol for this assay, that produces rapid and consistent results with low levels of basal superoxide anion (O2,) production by unstimulated haemocytes and high levels of this oxygen radical after cell stimulation. Among the different cell elicitors used (zymosan, laminarin, lipopolysaccharide and phorbol myristate acetate), laminarin (,-1,3-glucans , 2 mg mL,1) was the most potent cell activator for the haemocytes of all three penaeids and we recommend this immunostimulant to routinely evaluate shrimp respiratory burst. In general terms, the most elevated levels of O2, production, after cell stimulation with microbial components, were detected in L. schmitti. Interestingly, the stimulation profile of the haemocytes of L. vannamei was more similar to F. paulensis, than to L. schmitti, which is more phylogenetically related. [source]