Kinetics study of palm oil hydrolysis using immobilized lipase Candida rugosa in packed bed reactor

Continuous hydrolysis of palm oil triglyceride in organic solvent using immobilized Candida rugosa on the Amberlite MB-1 as a source of immobilized lipase was studied in packed bed reactor. The enzymatic kinetics of hydrolysis reaction was studied by changing the substrate concentration, reaction temperature and residence time(tau) in the reactor. At 55 degrees C, the optimum water concentration was found to be 15 % weight per volume of solution (%w/v). The Michaelis-Menten kinetic model was used to obtain the reaction parameters, Km(app) and V max(app). The activation energies were found to be quite low indicating that the lipase-catalyzed process is controlled by diffusion of substrates. The Michaelis-Menten kinetic model was found to be suitable at low water concentration 10-15 %w/v of solution. At higher water concentration, substrate inhibition model was used for data analysis. Reactor operation was found to play an important role in the palm oil hydrolysis kinetic.     

The effects of antibodies to heat shock protein 70 in fertilization and embryo development

The role of heat shock proteins in shielding organisms from environmental stress is illustrated by the large-scale synthesis of these proteins by the organisms studied to date. However, recent evidence also suggests an important role for heat shock proteins in fertilization and early development of mammalian embryos. We found that the presence of anti-HSP70 antibody significantly reduced tight binding of spermatozoa to the zona pellucida of bovine oocytes and interrupted completion of meiosis II and pronuclear formation. Furthermore, the presence of anti-HSP70 in culture medium from day 3 to day 9 of development increased apoptosis and significantly reduced the number of embryos reaching the blastocyst stage. We further observed that the proportion of apoptotic cells in bovine blastocysts was significantly lower after in-vitro culture with a prior exposure to increased temperature. However, nuclear localization of the p53 protein, which is thought to be essential for the up-regulation of genes involved in apoptosis and cell cycle arrest, was detected in the majority of nuclei in blastocysts exposed to increased temperature, whereas in their untreated (control) counterparts, p53 protein was only detected in the cytoplasm. The decrease in apoptosis after exposure of blastocysts to increased temperature may be attributed to cell cycle arrest resulting from nuclear localization of the p53 protein and/or to an increase in heat shock protein synthesis. We propose that HSP70 plays a critical role in fertilization and early embryonic development.     

Aberrant regulation and function of Src family tyrosine kinases: their potential contributions to glutamate-induced neurotoxicity

Excitotoxicity, a major cause of neuronal death in acute and chronic neurodegenerative diseases and conditions such as stroke and Parkinson's disease, is initiated by overstimulation of glutamate receptors, leading to calcium overload in affected neurons. The sustained high concentration of intracellular calcium constitutively activates a host of enzymes, notably the calcium-activated proteases calpains, neuronal nitric oxide synthase (nNOS) and NADPH oxidase (NOX), to antagonise the cell survival signalling pathways and induce cell death. Upon overactivation by calcium, calpains catalyse limited proteolysis of specific cellular proteins to modulate their functions; nNOS produces excessive amounts of nitric oxide (NO), which, in turn, covalently modifies specific enzymes by S-nitrosylation; and NOX produces excessive amounts of reactive oxygen species (ROS) to inflict damage to key metabolic enzymes. Presumably, key regulatory enzymes governing cell survival and cell death are aberrantly modified and regulated by calpains, NO and ROS in affected neurons; these aberrantly modified enzymes then cooperate to induce the death of affected neurons. c-Src, an Src family kinase (SFK) member, is one of the aberrantly regulated enzymes involved in excitotoxic neuronal death. Herein we review how SFKs are functionally linked to the glutamate receptors and the biochemical and structural basis of the aberrant regulation of SFKs. Results in the literature suggest that SFKs are aberrantly activated by calpain-mediated truncation and S-nitrosylation. Thus, the aberrantly activated SFKs are targets for therapeutic intervention to reduce the extent of brain damage caused by stroke.     

Well-differentiated epithelial thyroid cancer management in the Asia Pacific region: a report and clinical practice guideline.

CONTEXT: Thyroid cancer is among the 10 most common malignancies in populations in the Asia Pacific region, where access to various relevant health care resources varies widely. OBJECTIVE: An expert consensus conference was held to define regional patterns of practice and guidelines for optimal management of well-differentiated epithelial thyroid carcinomas. RESULTS: Practice patterns vary from country to country, as would be anticipated form their variety of ethnic and racial populations, health care systems, economies, and cultures. Thyroid cancer care is provided by a number of medical and surgical specialists, usually including endocrinologists. The thyroid surgical skills, experience, and outcomes vary widely in the region. Radioiodine is available, to a greater or lesser extent, is almost all countries. Laboratory services for thyroid function monitoring are universally accessible; thyroglobulin assays are available in most countries. Recombinant thyrotropin is approved for use in only two countries, but can be accessed in some others on a "named patient" compassionate need basis. Access to advanced imaging, for exampke, positron emission tomography (PET) scanning, is limited to a few countries. CONCLUSIONS: In light of these realities, appropriate strategies for initial treatment and postoperative monitoring of patients with thyroid cancer have been defined, and these are presented and discussed.     

Liraglutide,a once‐daily human GLP‐1 analogue,added to a sulphonylurea over 26 weeks produces greater improvements in glycaemic and weight control compared with adding rosiglitazone or placebo in subjects with Type 2 diabetes (LEAD‐1 SU)

Aim To compare the effects of combining liraglutide (0.6, 1.2 or 1.8 mg/day) or rosiglitazone 4 mg/day (all n ≥ 228) or placebo (n = 114) with glimepiride (2–4 mg/day) on glycaemic control, body weight and safety in Type 2 diabetes. Methods In total, 1041 adults (mean ± sd ), age 56 ± 10 years, weight 82 ± 17 kg and glycated haemoglobin (HbA_1c) 8.4 ± 1.0% at 116 sites in 21 countries were stratified based on previous oral glucose‐lowering mono : combination therapies (30 : 70%) to participate in a five‐arm, 26‐week, double‐dummy, randomized study. Results Liraglutide (1.2 or 1.8 mg) produced greater reductions in HbA_1c from baseline, (?1.1%, baseline 8.5%) compared with placebo (+0.2%, P < 0.0001, baseline 8.4%) or rosiglitazone (?0.4%, P < 0.0001, baseline 8.4%) when added to glimepiride. Liraglutide 0.6 mg was less effective (?0.6%, baseline 8.4%). Fasting plasma glucose decreased by week 2, with a 1.6 mmol/l decrease from baseline at week 26 with liraglutide 1.2 mg (baseline 9.8 mmol/l) or 1.8 mg (baseline 9.7 mmol/l) compared with a 0.9 mmol/l increase (placebo, P < 0.0001, baseline 9.5 mmol/l) or 1.0 mmol/l decrease (rosiglitazone, P < 0.006, baseline 9.9 mmol/l). Decreases in postprandial plasma glucose from baseline were greater with liraglutide 1.2 or 1.8 mg [?2.5 to ?2.7 mmol/l (baseline 12.9 mmol/l for both)] compared with placebo (?0.4 mmol/l, P < 0.0001, baseline 12.7 mmol/l) or rosiglitazone (?1.8 mmol/l, P < 0.05, baseline 13.0 mmol/l). Changes in body weight with liraglutide 1.8 mg (?0.2 kg, baseline 83.0 kg), 1.2 mg (+0.3 kg, baseline 80.0 kg) or placebo (?0.1 kg, baseline 81.9 kg) were less than with rosiglitazone (+2.1 kg, P < 0.0001, baseline 80.6 kg). Main adverse events for all treatments were minor hypoglycaemia (< 10%), nausea (< 11%), vomiting (< 5%) and diarrhoea (< 8%). Conclusions Liraglutide added to glimepiride was well tolerated and provided improved glycaemic control and favourable weight profile.