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.     

超声乳化术对小梁切除术患者眼压及滤过泡功能的影响

目的：观察使用丝裂霉素C小梁切除术成功/合格史的患者超声乳化术后眼压(IOP)控制及滤过泡功能。

方法：回顾性队列研究。收集2013-01-01/2015-12-31期间接受小梁切除术并随后进行白内障手术患者的数据。所有患者都曾成功/合格地进行过小梁切除术。他们通过透明角膜切口进行了简单的超声乳化手术。用Goldmann眼压计进行术后眼压随访,复查滤过泡情况。观察术后IOP控制、视力改善、抗青光眼药物的数量以及从小梁切除术到超声乳化术的时间,并与对照组进行比较。

结果：共13例15眼患者满足了研究标准,并且在小梁切除术后进行了简单的超声乳化术。其中2眼为继发性青光眼,13眼为原发性青光眼。所有的超声乳化术均在小梁切除术后至少6mo进行(平均14.7±4.3mo)。白内障术前仅1眼(6.7%)需要抗青光眼药物治疗,超声乳化术1a后,增加到4眼(26.7%),超声乳化术2a后,进一步增加到8眼(53.3%)。术后2a所需抗青光眼药水的数量在2～4种之间。在15眼中,白内障术前(平均13.4±2.9 mmHg)与超声乳化术后1a(平均14.1±3.2 mmHg,P=0.357)和2a(平均15.1±3.3 mmHg,P=0.212)的IOP控制无显著性差异。然而,术前平均LogMAR视力为1.52±1.00, 术后平均视力为0.53±0.54,超声乳化术后的视力改善是显著的(P=0.000)。

结论：结果显示,在不影响眼压控制的情况下,小梁切除术后白内障患者的视力明显改善。然而,手术后,特别是白内障手术后2a,抗青光眼眼药水的使用数量增加,证明了术后滤过泡功能的降低。白内障超声乳化手术后,患者应该被告知重新开始服用抗青光眼药物的可能性。白内障和青光眼手术的时机和顺序应优化,以获得最佳的手术效果。