Protein S multimers and monomers each have direct anticoagulant activity

BACKGROUND AND OBJECTIVES

Plasma protein S (PS) is an essential anticoagulant that has activated protein C-independent, direct anticoagulant activity (PS-direct). It was reported that monomeric purified PS has poor PS-direct and that a subpopulation of multimeric purified PS has high PS-direct and high affinity for phospholipids. We independently examined the relative PS-direct and affinity for phospholipids of monomeric and multimeric PS and we obtained contrasting results.

METHODS AND RESULTS

Unpurified recombinant protein S (rPS) was monomeric and had PS-direct potency similar to that of both PS in plasma and multimeric affinity-purified PS, as measured in plasma assays for PS-direct and in thrombin-generation assays. Multimers of unpurified rPS were not induced by ethylenediaminetetraacetic acid (EDTA), pH 2.5, NaSCN, or barium adsorption/elution. Multimers were induced by chromatography in the presence of EDTA and thus may be concentration-dependent. In contrast to a different report, monomers, dimers, trimers, and higher-order PS forms were clearly separated in sedimentation velocity experiments and multimers were not dissociated by adding Ca(2+). Active plasma-derived and recombinant immunoaffinity-purified PS were fractionated into monomers and multimers. On a mass basis, monomers and multimers had similar specific PS-direct and ability to compete with prothrombinase components (factors Xa/Va) for limiting phospholipids. FXa ligand blotted to both monomers and multimers.

CONCLUSIONS

Plasma PS-direct is similar to that of affinity-purified PS and unpurified rPS. Under our conditions, monomeric and multimeric PS have similar PS-direct and ability to compete for phospholipids. Discordant earlier findings are likely due to loss of PS-direct during conventional purification procedures.

Effect of composition and packing configuration on the dichroic optical properties of coinage metal nanorods

When nanorods of Au, Ag and some other elements are aligned with a preferred orientation with respect to light, their optical extinction characteristics become dependent on the polarization and angle of incidence of the light. This effect is explored here and it is shown that it could potentially be exploited to produce a 'colour-change coating'. However, particle-particle interactions are also likely to occur in such coatings, with red shifting of extinction spectra occurring for end-on-end configurations of monodisperse rods, and blue shifting for side-by-side configurations. Surprisingly, the particle-particle interactions are attenuated if they are between rods of differing aspect ratios, and this offers a useful new means of control of the optical properties of coatings of nanorods.

Nanofluidic channels fabrication and manipulation of DNA molecules

Nanofluidic channel arrays, which have a width of about 40 nm, depth of 60 nm and length of 50 mum, were created using a focused-ion-beam milling instrument on a silicon nitride film swiftly and exactly, as is necessary. Stained -DNA molecules were put inside these sub-100 nm conduits by capillary force and they were stretched and transferred along these conduits, which were dealt with activating reagent Brij aqueous solution in advance. The movements of DNA molecules in these channels were discussed. These nano-structure channels may be useful in the study and analysis of the statics as well as the dynamics of single biomolecules.

BRCA1 germline mutations in Chinese patients with hereditary breast and ovarian cancer

The role of germline BRCA1 mutations in hereditary breast and ovarian cancer (HBOC) has been well established in women in Western countries. However, relatively few studies have been carried out in Chinese population. In the present study, we investigated the frequency and spectrum of germline BRCA1 mutations in Chinese HBOC patients, all of whom were from northern part of China. A total of 25 women with HBOC and ten relatives were analyzed. Mutation screening was performed by a combination of denaturing high-performance liquid chromatography and sequencing. Seven protein-truncating mutations were identified. They were 667delG, 3347A → T, 3478del5, 4255delCT, 1235A → G, 2064G → T, and 5589del8. The first four of the mutations were putative ones never reported before. The prevalence of the protein-truncating mutations in this HBOC series was 40.0%, which is similar to that observed in Western hereditary ovarian cancer patients but higher than that reported in Chinese women with sporadic breast and ovarian cancer. Among the ten relatives we analyzed, six shared the same mutations with their affected relatives. No ovarian cancer was detected after 19 months of follow-up. This study showed that BRCA1 mutations play an important role in Northern Chinese HBOC.

Efficiency and efficacy of multi-channel gastric electrical stimulation

Gastric electrical stimulation (GES) using single channel has been under investigation for its therapeutic potential for gastroparesis. The aim of this study was to study the efficacy and efficiency of multi-channel GES in accelerating gastric emptying in dogs. The study was performed in eight dogs, and gastric emptying of liquid was assessed in three randomized sessions of control, one-channel GES and four-channel GES. It was found that (i) GES of both one-channel and four-channel was able to completely entrain the slow waves in the entire stomach. However, the stimulation energy required by four-channel GES was only 1% of that required by one-channel GES. (ii) Four-channel, but not one-channel, GES significantly and substantially accelerated gastric emptying. An increase of 121.0 and 93.9% was noted with four-channel GES at 30 and 60 min after the meal, respectively. It was concluded that four-channel GES is substantially more efficient and effective than conventional single-channel GES in improving gastric emptying. It is worthy to explore its therapeutic potential for gastroparesis in clinical settings.

Primary adenovirus-specific cytotoxic T lymphocyte response occurs after viral clearance and liver enzyme elevation

The virus-specific cytotoxic T lymphocyte (CTL) response is a major obstacle to effective delivery of adenovirus gene therapy. However, its relative role in viral clearance, transgene elimination and hepatotoxicity remains unclear. In this paper, we present an analysis of viral clearance and liver toxicity in relation to the induction of the virus-specific CD8 T-cell response revealed by an MHC class I tetramer. A surprisingly high number of tetramer+ CD8 T cells were found in the liver and lung and reached peak values at days 8 and 10, respectively, post-infection. Nearly 100% of these tetramer+ CD8 T cells expressed high levels of granzyme B and IFNgamma. Remarkably, liver viral load and liver enzyme elevation peaked early, at days 2 and 4, respectively, post-infection, before the specific CTL response was detectable. After generation of CTLs, there was only minimal liver damage or further decrease in virus titer. These results indicated that the primary peak response of tetramer+ CTLs does not correlate with the elimination of adenovirus or liver cytotoxic response.

DNA pooling analysis of ADHD and genes regulating vesicle release of neurotransmitters

ADHD is one of the most prevalent, and heritable behavioural disorders in childhood. Genetic associations have been reported with polymorphic variants within or near to dopamine pathway genes. Recently snap-25 has also shown association with ADHD in several datasets. We therefore investigated other genes that produce proteins that interact with SNAP-25 in the mechanism of vesicular release of neurotransmitters at the synapse. A total of 106 SNPs were screened for minor allele frequency greater than 5% and 61 SNPs selected for analysis in DNA pools made up from an ADHD clinical sample of DSM-IV combined type probands (n = 180) and a control sample of 90 males and 90 females. Initial screening identified several SNPs that showed allele frequency differences of 5% or more. One SNP in the synaptophysin gene showed suggestive evidence of association following case-control and TDT analysis and warrants further investigation.

Salt-stress-responsive membrane proteins in Rhodobacter sphaeroides f. sp. denitrificans IL 106

The salt-mediated-stress response in Rhodobacter sphaeroides f. sp. denitrificans IL 106 was investigated by culturing cells in the presence and in the absence of NaCl in growth media. Fractionation of cells followed by SDS-PAGE and 2D-PAGE revealed an increase in the levels of membrane proteins of 39 and 50 kDa and a decrease in the level of a membrane protein of 52 kDa with increasing levels of external NaCl. The proteins were isolated and sequenced. The polypeptide of 50 kDa in the inner membrane was assigned to an ATP synthase beta chain and that of 52 kDa in the outer membrane to a flagellar filament protein. As the N terminal of the 39 kDa protein in the outer membrane was blocked, partial proteolysis was carried out and four peptides were sequenced. Each sequence exhibited no significant homology with those available in databases, suggesting that the polypeptide of 39 kDa (named SspA) is a novel salt-stress-induced protein.

Characterization of the nociceptin receptor (ORL-1) agonist, Ro64-6198, in tests of anxiety across multiple species

RATIONALE

Previous studies have demonstrated behaviors indicative of anxiolysis in rats pretreated with the nociceptin receptor (opioid receptor like-1, ORL-1) agonist, Ro64-6198.

OBJECTIVES

The aim of this study was to examine the effects of Ro64-6198 in anxiety models across three species: rat, guinea pig, and mouse. In addition, the receptor specificity of Ro64-6198 was studied, using the ORL-1 receptor antagonist, J-113397, and ORL-1 receptor knockout (KO) mice. Finally, neurological studies examined potential side effects of Ro64-6198 in the rat and mouse.

RESULTS

Ro64-6198 (3-10 mg/kg) increased punished responding in a rat conditioned lick suppression test similarly to chlordiazepoxide (6 mg/kg). This effect of Ro64-6198 was attenuated by J-113397 (10 mg/kg), but not the mu opioid antagonist, naltrexone (3 mg/kg). In addition, Ro64-6198 (1-3 mg/kg) reduced isolation-induced vocalizations in rat and guinea pig pups. Ro64-6198 (3 mg/kg) increased the proportion of punished responding in a mouse Geller-Seifter test in wild-type (WT) but not ORL-1 KO mice, whereas diazepam (1-5.6 mg/kg) was effective in both genotypes. In rats, Ro64-6198 reduced locomotor activity (LMA) and body temperature and impaired rotarod, beam walking, and fixed-ratio (FR) performance at doses of 10-30 mg/kg, i.e., three to ten times higher than an anxiolytic dose. In WT mice, Ro64-6198 (3-10 mg/kg) reduced LMA and rotarod performance, body temperature, and FR responding, but these same measures were unaffected in ORL-1 KO mice. Haloperidol (0.3-3 mg/kg) reduced these measures to a similar extent in both genotypes. These studies confirm the potent, ORL-1 receptor-mediated, anxiolytic-like effects of Ro64-6198, extending the findings across three species. Ro64-6198 has target-based side effects, although the magnitude of these effects varies across species.

Distortion and segregation in a dislocation core region at atomic resolution

The structure of an isolated, Ga terminated, 30 degree partial dislocation in GaAs:Be is determined by high resolution transmission electron microscopes and focal series reconstruction. The positions of atomic columns in the core region are measured to an accuracy of better than 10 pm. A quantitative comparison of the structure predicted by an ab initio electronic structure total energy calculation to the experiment indicates that theory and experiment agree to within 20 pm. Further analysis shows the deviations between theory and experiment appear to be systematic. Electron energy loss spectroscopy establishes that defects segregate to the core region, thus accounting for the systematic deviations.

Expression of endothelial nitric oxide synthase traffic inducer in the placentas of women with pre-eclampsia

OBJECTIVE

To investigate the expression of endothelial nitric oxide synthase traffic inducer (NOSTRIN) in the placenta of women with pre-eclampsia (PE) and discuss its role in the pathogenesis of PE.

METHODS

Western blot analysis was used to detect the expression of NOSTRIN and endothelial nitric oxide synthase (eNOS). The activity of eNOS in placental tissue was assayed by spectrophotometry. Serum and placental NO(2)/NO(3), the stable metabolic end product of NO, was measured using nitrate reductase.

RESULTS

Western blot analysis showed that the protein level of NOSTRIN was significantly higher in women with PE than in the control group (P<0.01). However, no significant difference between groups was observed in the expression of placental eNOS (P>0.05). The activity of eNOS was significantly decreased in women with PE (13.727+/-3.58 U/mg) compared with the control group (21.69+/-3.84 U/mg) (P<0.01). The placental levels of NO(2)/NO(3) were significantly lower in women with PE (27.53+/-8.51 micromol/mg) than in the control group (44.38+/-9.59 micromol/mg) (P<0.01). The levels of serum NO(2)/NO(3) were significantly lower in women with PE (48.56+/-8.49 micromol/L) than in the control group (65.37+/-9.61 micromol/L) (P<0.01). A significant negative correlation existed between the expression of NOSTRIN protein and the activity of eNOS in the placental tissues of women with PE (r=-0.57, P<0.01).

CONCLUSION

The level of NOSTRIN expression in the placental tissues of women with PE is increased and is negatively correlated with the activity of eNOS-which may play an important role in the pathogenesis of PE.

Development and psychometric tests of the Chinese-version Low Vision Quality of Life Questionnaire

BACKGROUND/AIMS

To develop and assess the psychometric validity of a Chinese language Vision Health related quality-of-life (VRQoL) measurement instrument for the Chinese visually impaired.

METHODS

The Low Vision Quality of Life Questionnaire (LVQOL) was translated and adapted into the Chinese-version Low Vision Quality of Life Questionnaire (CLVQOL). The CLVQOL was completed by 100 randomly selected people with low vision (primary group) and 100 people with normal vision (control group). Ninety-four participants from the primary group completed the CLVQOL a second time 2 weeks later (test-retest group). The internal consistency reliability, test-retest reliability, item-internal consistency, item-discrimination validity, construct validity and discriminatory power of the CLVQOL were calculated.

RESULTS

The review committee agreed that the CLVQOL replicated the meaning of the LVQOL and was sensitive to cultural differences. The Cronbach's alpha coefficient and the split-half coefficient for the four scales and total CLVQOL scales were 0.75-0.97. The test-retest reliability as estimated by the intraclass correlations coefficient was 0.69-0.95. Item-internal consistency was > 0.4 and item-discrimination validity was generally < 0.40. The Varimax rotation factor analysis of the CLVQOL identified four principal factors. the quality-of-life rating of four subscales and the total score of the CLVQOL of the primary group were lower than those of the Control group, both in hospital-based subjects and community-based subjects.

CONCLUSION

The CLVQOL Chinese is a culturally specific vision-related quality-of-life measure instrument. It satisfies conventional psychometric criteria, discriminates visually healthy populations from low vision patients and may be valuable in screening the local community as well as for use in clinical practice or research.