Deleterious effects of xanthine oxidase on rat liver endothelial cells after ischemia/reperfusion

AbstractPrevious studies have demonstrated that reactive oxygen species are involved in ischemic injury. The present work was undertaken to determine in vivo the role of xanthine oxidase in the oxygen free radical production during rat liver ischemia and to examine the activity of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) during the same period. Our results indicate a 4-fold increase in xanthine oxidase activity between 2 and 3 hours of normothermic ischemia, in parallel with a decrease in cell viability. Moderate hypothermia delays both events. Under the same conditions, the activity of oxygen radical scavenging enzymes remains unchanged. Moreover, we have compared in vitro the susceptibility of isolated liver cells to an oxidative stress induced by O2·−, H2O2 and OH. Our results reveal that endothelial cells are much more susceptible to reactive oxygen species than hepatocytes, probably because they lack H2O2-detoxifying enzymes. These findings suggest that xanthine oxidase might play a major role in the ischemic injury mainly at the level of the sinusoidal space where most endothelial cells are located

Biological functions of lysosomal membrane-associated glycoproteins

Lysosomes are the final repository of degradation products from the extracellular and intracellular spaces. The lysosomal membrane forms a unique vacuole participating in both endocytosis and autophagocytosis. It is extremely resistant to degradation by lysosomal hydrolases, maintains an acidic intralysosomal environment, transports amino acids and oligosaccharides produced by lysosomal hydrolases, interacts and fuses with other membrane organelles, such as endosomes and phagosomes, and with the plasma membrane.Biomedical Reviews 1997; 8: 119-125

Agriculture and Dairy Production Systems in China: An Overview and Case Studies

The Chinese dairy industry is growing rapidly. Since 1980, the rate of increase in dairy cattle in China's dairy industry (+210,000 cows per year) is 1.7 times higher than the rate of decline of dairy cattle in the US dairy industry (-124,000 cows per year). If the current trends do not change, there will be as many dairy cows in China as in the US-approximately 7.45 million cows in 2012. This two-part Discussion Paper presents the context in which the Chinese dairy industry is developing (Part I) and a study of the Dairy Farm systems and case studies of five farms in the Province of Yunnan, the city of Beijing and the province of Heilongjiang (Part II).Chinese Dairy Industry, Dairy Cows in China, Development of the Chinese Dairy Industry, Chinese Dairy Farm Case Studies, Consumer/Household Economics, Farm Management, International Development, International Relations/Trade, Productivity Analysis,

Endocytosis of hyaluronidase-1 by the liver

International audienceIt has been suggested that intracellular hyaluronidase-1 (Hyal-1), considered as a lysosomal enzyme, originates from the endocytosis of the serum enzyme. To check this proposal we have investigated the uptake of recombinant human hyaluronidase-1 (rhHyal-1) by mouse liver and its intracellular distribution, making use of centrifugation methods. Experiments were performed on wild type mice injected with 125I-rhHyal-1 and on null mice (Hyal-1 -/-) injected with the unlabelled enzyme. Mice were euthanized at increasing times after injection Activity of the unlabelled enzyme was determined by zymography. Intracellular distribution of the Hyal-1 was investigated by differential and isopycnic centrifugation. Results indicated that rhHyal-1 is endocytosed by the liver, mainly by sinusoidal cells and follows the intracellular pathway described for many endocytosed proteins that find themselves eventually in lysosomes. However, Hyal-1 endocytosis has some particular features. Endocytosed rhHyal-1 is quickly degraded. Its distribution after differential centrifugation differs from the distribution of β-galactosidase, taken as reference enzyme of lysosomes. After isopycnic centrifugation in a sucrose gradient, endocytosed rhHyal-1 behaves like β-galactosidase soon after injection but Hyal-1 distribution is markedly less affected than the distribution of β-galactosidase by a prior injection of Triton WR-1339 to the mice. This agent is a specific density perturbant of lysosomes. Behaviour in centrifugation of endogenous liver Hyal-1, identified by HA zymography exhibits some kinship with the behaviour of the endocytosed enzyme, suggesting that it could originate from an endocytosis of the serum enzyme. Overall, these results could be explained by supposing that active endocytosed Hyal-1 is mainly present in early lysosomes. Although its degradation half-time is short, Hyal-1 could exert its activity owing to a constant supply of active molecules from the blood

Forage nutritive value and predicted fiber digestibility of Kernza intermediate wheatgrass in monoculture and in mixture with red clover during the first production year

Kernza intermediate wheatgrass is thefirst perennial grain crop in the world and has been de-veloped with conventional breeding to increase seed yield of forage intermediate wheatgrass(Thinopyrum intermedium(Host) Barkworth & D.R. Dewey). When managed for dual-use (grainand forage), Kernza intermediate wheatgrass can produce grain, crop residue (straw) in thesummer, and green forage in the spring and fall. Mixtures of this grass with legumes could in-crease forage yield and nutritive value and provide other environmental and economic benefits.Despite the growing interest in these dual-use production systems, forage nutritive value ofKernza intermediate wheatgrass forage in a dual-use system in the Upper Midwest is unknown. Areplicatedfield experiment was established in two locations in southern Wisconsin (Arlingtonand Lancaster) with two treatments: Kernza intermediate wheatgrass grown in monoculture andmixture with red clover (Trifolium pratenseL.). Forage samples were collected at late vegetativestage in the spring, at grain harvest in the summer, and at the end of the regrowth period in thefall. Forage nutritive value of the monoculture was greatest in the spring with 456, 249 and 225 gkg−1for neutral detergentfiber (NDF), acid detergentfiber (ADF) and crude protein (CP), re-spectively; lowest in the summer with 702, 427 and 51 g kg−1NDF, ADF and CP, respectively,and intermediate in the fall with 590, 337 and 119 g kg−1NDF, ADF and CP, respectively.Predicted total-tract neutral detergentfiber digestibility (ttNDFD) was 0.53 for the spring forageand averaged 0.37 for the summer and fall forage, with no differences between the mixture andmonoculture. The relative forage quality (RFQ) for the monoculture was 175 for the springforage, 65 for the summer residue, and 116 for the fall. Intercropping red clover with Kernzaintermediate wheatgrass increased CP of the summer crop residue by 69%, and increased CP andRFQ of the fall forage by 49% and 11%, respectively, while reducing NDF and ADF of the fallforage by 25% and 18%, respectively. Therefore, Kernza intermediate wheatgrass forage is sui-table for lactating beef cows, dairy cows, and growing heifers when harvested in the spring andfall, and it offers high potential for dual-use grain and forage systems

A Discrete-Event, Simulated Social Agent-Based Network Transmission (DESSABNeT) model for communicable diseases: Method and validation using SARS-CoV-2 data in three large Australian cities

IMPORTANCE: During pandemics Agent Based Models (ABMs) can model complex, fine-grained behavioural interactions occurring in social networks, that contribute to disease transmission by novel viruses such as SARS-CoV-2. OBJECTIVE: We present a new agent-based model (ABM) called the Discrete-Event, Simulated Social Agent based Network Transmission model (DESSABNeT) and demonstrate its ability to model the spread of COVID-19 in large cities like Sydney, Melbourne and Gold Coast. Our aim was to validate the model with its disease dynamics and underlying social network. DESIGN: DESSABNeT relies on disease transmission within simulated social networks. It employs an epidemiological SEIRD+M (Susceptible, exposed, infected, recovered, died and managed) structure. One hundred simulations were run for each city, with simulated social restrictions closely modelling real restrictions imposed in each location. MAIN OUTCOME(S) AND MEASURE(S): The mean predicted daily incidence of COVID-19 cases were compared to real case incidence data for each city. R(eff) and health service utilisation outputs were compared to the literature, or for the Gold Coast with daily incidence of hospitalisation. RESULTS: DESSABNeT modelled multiple physical distancing restrictions and predicted epidemiological outcomes of Sydney, Melbourne and the Gold Coast, validating this model for future simulation work. CONCLUSIONS AND RELEVANCE: DESSABNeT is a valid platform to model the spread of COVID-19 in large cities in Australia and potentially internationally. The platform is suitable to model different combinations of social restrictions, or to model contact tracing, predict, and plan for, the impact on hospital and ICU admissions, and deaths; and also the rollout of COVID-19 vaccines and optimal social restrictions during vaccination