Home About us Contact
|
Home About us Contact | ||
|
|
||
Glycerol Levels (glycerol + level)
Selected AbstractsAge-dependent changes in tolerance to cold and accumulation of cryoprotectants in overwintering and non-overwintering larvae of European corn borer Ostrinia nubilalisPHYSIOLOGICAL ENTOMOLOGY, Issue 4 2008STEFANOS S. ANDREADIS Abstract The age-dependent cold hardiness profile of Ostrinia nubilalis is compared between nondiapausing and diapausing larvae, as well as with field-collected larvae. The results suggest that both cold tolerance and accumulation of cryoprotectants depends upon the age of O. nubilalis larva. Late fifth-instar nondiapausing larvae are more cold tolerant than younger fifth-instars because they show enhanced ability to withstand sub-zero temperatures. No appreciable difference is observed between the experimental groups of diapausing larvae as far as their supercooling ability and tolerance at sub-zero temperatures above the supercooling point. In general, both field-collected and diapausing larvae are more cold tolerant than nondiapausing larvae, indicating a direct link between diapause and cold hardiness. The age of diapausing larvae affects the ability to accumulate glycerol. Glycerol levels of 45-day-old diapausing larvae are significantly higher (2.7-fold) compared with 90-day-old diapausing larvae. Moreover, diapausing larvae display a five- to 13-fold higher glycerol content compared with nondiapausing larvae. There is a trend for an age-dependent cold hardiness profile in O. nubilalis and further tests that could demonstrate a causal relationship between age and cold tolerance are needed. [source] Evaluation of Glycerol from Biodiesel Production as a Feed Ingredient for Channel Catfish, Ictalurus punctatusJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2010Menghe H. Li Glycerol is the main by-product of biodiesel production from vegetable oils and animal fats. It has been evaluated as an energy source for several farm animals. A study was conducted to examine the effects of various levels of glycerol in channel catfish, Ictalurus punctatus, diets. Fish with mean initial weight of 6.8 ± 0.1 g were stocked in 110-L flow-through aquaria and fed practical diets containing 0, 5, 10, 15, and 20% glycerol for 9 wk. There were no significant differences in feed consumption, weight gain, feed efficiency ratio, and liver lipid level among fish fed diets containing 0, 5, and 10% glycerol. However, fish fed diets containing 15 and 20% glycerol had reduced weight gain, feed efficiency, and liver lipid content. Survival was not affected by dietary glycerol levels. Blood glucose level was significantly higher in fish fed 5% glycerol than fish fed other diets. Fillet protein and fat generally decreased and fillet moisture increased as dietary glycerol level increased. It appears that channel catfish can utilize about 10% glycerol in the diet without adverse effects on feed consumption, weight gain, feed efficiency ratio, hemoglobin, hepatosomatic index, and liver lipid. [source] Metabolic changes in the liver graft monitored continuously with microdialysis during liver transplantation in a pig modelLIVER TRANSPLANTATION, Issue 5 2002Grzegorz Nowak MD Microdialysis provides the opportunity to continuously monitor metabolic changes in tissue. The aim of the study is to monitor metabolic changes in the liver graft over time during transplantation in a pig model. Fourteen littermate female pigs with a body weight of 30 to 34 kg were used for seven orthotopic liver transplantations. Intrahepatic implantation of a microdialysis catheter into the liver graft was performed in the donor. Microdialysis samples were collected at 20-minute intervals during the donor operation, cold preservation, and for 7 hours after reperfusion in the recipient. Glucose, lactate, pyruvate, and glycerol concentrations were measured. After cold perfusion, glucose, lactate, and glycerol levels increased, whereas pyruvate levels decreased rapidly. During cold storage, glucose and glycerol levels increased, whereas lactate levels remained stable and pyruvate levels were undetectable. During implantation of the liver graft, glucose, lactate, and glycerol levels showed an accelerated increase. After portal reperfusion, glucose, lactate, and glycerol levels continued to increase for another 40 to 60 minutes, after which they decreased and finally settled at normal levels. At this time, pyruvate levels increased, with a peak within 2 hours after reperfusion, and then decreased to normal levels. Calculated lactate-pyruvate ratio increased after cold perfusion and remained stable during cold storage. During rewarming, it showed an accelerated increase, but after reperfusion, it decreased rapidly. Rewarming and reperfusion are most harmful to the liver, reflected by an accelerated increase in glucose and glycerol levels and lactate-pyruvate ratio. High intrahepatic glucose levels during ischemia appear to be a liver-specific event, which may represent glycogen degradation in injured hepatocytes. [source] Peritoneal Cooling May Provide Improved Protection for Uncontrolled Donors After Cardiac Death: An Exploratory Porcine StudyAMERICAN JOURNAL OF TRANSPLANTATION, Issue 6 2009A. P. Navarro Uncontrolled donation after cardiac death (DCD) renal transplantation relies on rapid establishment of organ preservation interventions. We have developed a model of the uncontrolled DCD, comparing current in situ perfusion (ISP) techniques with additional peritoneal cooling (PC). Ten pigs were killed and subjected to a 2 h ischemia period. The ISP group modeled current DCD protocols. The PC group (PC) modeled current protocols plus PC. Two animals were used as controls and subjected to 2 h of warm ischemia. Core renal temperature and microdialysis markers of ischemia were measured. Preservation interventions began at 30 min, with rapid laparotomy and kidney recovery performed at 2 h, prior to machine perfusion viability testing. The final mean renal temperature achieved in the ISP group was 26.3°C versus 16.9°C in the PC group (p = 0.0001). A significant cryopreservation benefit was suggested by lower peak microdialysate lactate and glycerol levels (ISP vs. PC, p = 0.0003 and 0.0008), and the superiority of the PC group viability criteria (p = 0.0147). This pilot study has demonstrated significant temperature, ischemia protection and viability assessment benefits with the use of supplementary PC. The data suggests a need for further research to determine the potential for reductions in the rates of ischemia-related clinical phenomena for uncontrolled DCDs. [source] Responses of protein phosphatases and cAMP-dependent protein kinase in a freeze-avoiding insect, Epiblema scudderianaARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2006Thomas D. Pfister Abstract Larvae of the goldenrod gall moth, Epiblema scudderiana, use the freeze avoidance strategy of winter cold hardiness and show multiple metabolic adaptations for subzero survival including accumulation of large amounts of glycerol as a colligative antifreeze. Induction and regulation of cold hardiness adaptations requires the intermediary action of signal transduction enzymes. Changes in the activities of several signaling enzymes including cAMP-dependent protein kinase (PKA), protein phosphatases 1 (PP1), 2A, 2C, and protein tyrosine phosphatases (PTPs) were monitored over the winter and during experimental exposures of larvae to subzero temperatures (,4°C, a temperature that triggers rapid glycerol synthesis, or ,20°C, a common midwinter ambient temperature) or anoxia. A strong increase in the amount of active PP1 in the latter part of the winter may be responsible for shutting off glycogenolysis once glycerol levels are maximized. There appears to be a limited role for PKA in overwintering but PP2A and PP2C activities rose when larvae were exposed to ,20°C and PTP activities rose significantly over the winter months and also in response to laboratory subzero (,20°C) and anoxia exposures. The strong responses by PTPs suggest that these may be involved in cell cycle and growth arrest during winter diapause. Arch. Insect Biochem. Physiol. 62:43,54, 2006. © 2006 Wiley-Liss, Inc. [source] | ||||||||||