On the ratio T2/T1 for non‐Ohmic spectral densities

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/101/1/10.1063/1.468089.Defining T 1 and T 2 to be the population and phase relaxation times, respectively, for a two‐level system coupled to a bath, previous work for Ohmic spectral densities has shown, surprisingly, that in some instances T 2≳2T 1. This note shows that this inequality can also be realized for non‐Ohmic spectral densities

Serum Homocysteine and Intracranial Aneurysms

Subarachnoid haemorrhage (SAH) occurs as a result of rupture of intracranial aneurysms. SAH causes significant morbidity and mortality. In addition, SAH leads to significant financial burden. In this chapter, we will look into the association between raised serum homocysteine and intracranial aneurysms. In a study on the Han Chinese patients with intracranial aneurysm who were admitted to the hospital, the mean serum total homocysteine level in the patient group with intracranial aneurysm was significantly higher than those in the control group. In the same study, the patients with raised serum homocysteine had 2.196 higher risk of developing intracranial aneurysms. Ren et al. proposed that homocysteine should be seen as an indicator of the risk of intracranial aneurysm and not a direct cause of intracranial aneurysm. In another study, homocysteine increases the development of intracranial aneurysms in rats. Endothelial damage is an early change in the walls of intracranial aneurysms. Polymorphisms of the genes coding for the various components of the vessel walls may be associated with the formation of intracranial aneurysms. In a previous animal study, the size of intracranial aneurysms is significantly smaller in the mice with inducible nitric oxide synthase (iNOS) compared with the mice without iNOS

Extending Bilingual WordNet via Hierarchical Word Translation Classification

PACLIC 23 / City University of Hong Kong / 3-5 December 200

Endotoxin and CD14 in the progression of biliary atresia

<p>Abstract</p> <p>Background</p> <p>Biliary atresia (BA) is a typical cholestatic neonatal disease, characterized by obliteration of intra- and/or extra-hepatic bile ducts. However, the mechanisms contributing to the pathogenesis of BA remain uncertain. Because of decreased bile flow, infectious complications and damaging endotoxemia occur frequently in patients with BA. The aim of this study was to investigate endotoxin levels in patients with BA and the relation of these levels with the expression of the endotoxin receptor, CD14.</p> <p>Methods</p> <p>The plasma levels of endotoxin and soluble CD14 were measured with a pyrochrome Limulus amebocyte lysate assay and enzyme-linked immunosorbent assay in patients with early-stage BA when they received the Kasai procedure (KP), in patients who were jaundice-free post-KP and followed-up at the outpatient department, in patients with late-stage BA when they received liver transplantation, and in patients with choledochal cysts. The correlation of CD14 expression with endotoxin levels in rats following common bile duct ligation was investigated.</p> <p>Results</p> <p>The results demonstrated a significantly higher hepatic CD14 mRNA and soluble CD14 plasma levels in patients with early-stage BA relative to those with late-stage BA. However, plasma endotoxin levels were significantly higher in both the early and late stages of BA relative to controls. In rat model, the results demonstrated that both endotoxin and CD14 levels were significantly increased in liver tissues of rats following bile duct ligation.</p> <p>Conclusions</p> <p>The significant increase in plasma endotoxin and soluble CD14 levels during BA implies a possible involvement of endotoxin stimulated CD14 production by hepatocytes in the early stage of BA for removal of endotoxin; whereas, endotoxin signaling likely induced liver injury and impaired soluble CD14 synthesis in the late stages of BA.</p

Increasing the civil service retirement age in Hong Kong : a study of policy processes and dynamics

published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

Telomerase prevents accelerated senescence in glucose-6-phosphate dehydrogenase (G6PD)-deficient human fibroblasts

Fibroblasts derived from glucose-6-phosphate dehydrogenase (G6PD)-deficient patients display retarded growth and accelerated cellular senescence that is attributable to increased accumulation of oxidative DNA damage and increased sensitivity to oxidant-induced senescence, but not to accelerated telomere attrition. Here, we show that ectopic expression of hTERT stimulates telomerase activity and prevents accelerated senescence in G6PD-deficient cells. Stable clones derived from hTERT-expressing normal and G6PD-deficient fibroblasts have normal karyotypes, and display no sign of senescence beyond 145 and 105 passages, respectively. Activation of telomerase, however, does not prevent telomere attrition in earlier-passage cells, but does stabilize telomere lengths at later passages. In addition, we provide evidence that ectopic expression of hTERT attenuates the increased sensitivity of G6PD-deficient fibroblasts to oxidant-induced senescence. These results suggest that ectopic expression of hTERT, in addition to acting in telomere length maintenance by activating telomerase, also functions in regulating senescence induction

Atherosclerosis at Extracranial Carotid Vessels and Serum Homocysteine

In this chapter we will discuss more about the role of homocysteine in atherosclerosis and also association between serum homocysteine with extracranial carotid atherosclerosis. Carotid atherosclerosis comprises an increase in carotid intima-media (CIMT) thickening, plaque formation and carotid stenosis. Atherogenic property of homocysteine was discovered in 1969. Atherosclerosis is initiated by endothelial dysfunction. One of the causes of endothelial abnormality is homocysteine. The development of aggregates of homocysteinylated lipoproteins with microorganisms obstructs the vasa vasorum in vulnerable plaques. In one study, serum homocysteine in the highest quartile was independently associated with extracranial carotid artery stenosis ≥50%. In another study, raised serum homocysteine was also independently associated with severe extracranial carotid stenosis in both genders. In other studies, serum homocysteine was significantly associated with carotid artery stenosis in internal carotid arteries and external carotid arteries as well as the degree of stenosis. The hypertensive patients who had raised serum homocysteine were reported to have higher risk of developing asymptomatic extracranial carotid artery stenosis

Cellular glucose-6-phosphate dehydrogenase (G6PD) status modulates the effects of nitric oxide (NO) on human foreskin fibroblasts

AbstractGlucose-6-phosphate dehydrogenase (G6PD) plays an important role in cellular redox homeostasis, which is crucial for cell survival. In the present study, we found that G6PD status determines the response of cells exposed to nitric oxide (NO) donor. Treatment with NO donor, sodium nitroprusside (SNP), caused apoptosis in G6PD-deficient human foreskin fibroblasts (HFF1), whereas it was growth stimulatory in the normal counterpart (HFF3). Such effects were abolished by NO scavengers like hemoglobin. Ectopic expression of G6PD in HFF1 cells switched the cellular response to NO from apoptosis to growth stimulation. Experiments with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and 8-bromo-cGMP showed that the effects of NO on HFF1 and HFF3 cells were independent of cGMP signalling pathway. Intriguingly, trolox prevented the SNP-induced apoptosis in HFF1 cells. These data demonstrate that G6PD plays a critical role in regulation of cell growth and survival

TLR7 and TLR8 Gene Variations and Susceptibility to Hepatitis C Virus Infection

Toll-like receptors (TLRs) play pivotal roles in the innate immune system and control inflammatory responses and adaptive immunity. We previously evaluated associations between TLR7 and TLR8 gene SNPs and susceptibility to hepatitis C virus (HCV) infection. Our results suggested that TLR7IVS2-151G and TLR8-129G alleles were present at higher frequency in males of an HCV-infected group as compared to a control group (24.1% vs. 14.4%, p = 0.028; 17.6% vs. 6.8%, p = 0.004, respectively). Based upon their recognition of single stranded viral RNA, this suggested that TLR7 and TLR8 played a significant role in anti-HCV immune responses. Here, we studied the functional effects of these polymorphisms by analyzing the mRNA expressions of TLR7 and TLR8 and cytokine production induced ex vivo by TLR7- and TLR8-specific agonists using whole blood of subjects with different genotypes. The percentage of CD14+ cells from those with an AG haplotype that expressed TLR7 and TLR8 was significantly lower, but higher in intensity compared to cells from those with GG and AC haplotypes. Cells from those with an AG haplotype produced more IFN-α and less amounts of pro-inflammatory cytokines upon stimulation. This suggests that variations in TLR7 and TLR8 genes might impair immune responses during HCV infection

Alpha-Glucosidase Inhibitory and Antioxidant Activity of Solvent Extracts and Fractions of Typha domingensis (Typhaceae) Fruit

Purpose: To identify a solvent fraction with potent antiglucosidase and antioxidant activities from the fruit of Typha domingensis.Methods: Extracts were prepared using hexane, chloroform, ethyl acetate, acetone (AE), methanol, and water. Antiglucosidase and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities of extracts were assessed. The most active extract was partitioned into chloroform, ethyl acetate, butanol (BF) and water, and the antiglucosidase and radical scavenging activities of the fractions were determined. Mode of inhibition of the strongest antiglucosidase fraction was investigated. Polyphenol, coumarin, proanthocyanidin (TPro), and hydroxycinnamic acid contents of the extracts and fractions were evaluated.Results: AE had the highest antiglucosidase (EC50 = 12.36 μg/mL) and radical scavenging (EC50 = 8.57 μg/mL) activities. Solvent-partitioning of AE resulted in BF, which showed markedly stronger antiglucosidase activity (EC50 = 4.27 μg/mL) than quercetin (EC50 = 22.18 μg/mL). BF also had potent radical scavenging activity (EC50 = 7.20 μg/mL). BF was rich in TPro (735.65 mg/g) and was a competitive glucosidase inhibitor. TPro content correlated with antiglucosidase (R2 = 0.709) and DPPH scavenging activities (R2 = 0.838).Conclusion: TPro-rich BF of T. domingensis fruit is a highly potent glucosidase inhibitor and radical scavenger. The findings demonstrate a potential for the development of natural antihyperglycemic agents with antioxidant effect from T. domingensis fruit.Keywords: Typha domingensis, Antiglucosidase, Antioxidant, Proanthocyanidin, Hydroxycinnamic acid, Polyphenol, Coumari