Construction and analysis of a suppression subtractive hybridization library of regeneration-related genes in soybean

The development of a genetic transformation system is needed to address the problem of the low efficiency associated with soybean regeneration. To contribute to the enhancement of the soybean regenerative capacity, we explored the developmental mechanisms of soybean regeneration at the molecular level using a suppression subtractive hybridization cDNA library constructed from cotyledonary nodes of soybean cultivar DN50. A total of 918 positive clones were identified and screened, with most inserted fragments ranging from 100 to 750 bp. Of these, 411 differentially expressed functional expressed sequence tags were identified and annotated based on their similarity to orthologs and paralogs detected in GenBank using the nucleotide and translated nucleotide Basic Local Alignment Search Tools. Functional analysis revealed that the associated genes were involved in signal transduction, synthesis, and metabolism of macromolecules, glucose and protein synthesis and metabolism, light and leaf morphogenesis, regulation of apoptosis, cell defense, cell wall differentiation, and a variety of hormone and cytokinin-mediated signaling pathways. The information uncovered in our study should serve as a foundation for the establishment of an efficient and stable genetic transformation system for soybean regeneration.

Genetic diversity of HLA-DRB1 alleles in the Tujia population of Wufeng, Hubei Province, China

We established a genetic database by investigating human leukocyte antigen (HLA)-DRB1 allelic frequencies in a disease-association study in the Tujia population in Wufang, Hubei, China. The allele frequencies of the HLA-DRB1 locus in 262 healthy, unrelated Tujia individuals living in the Wufeng region of the Hubei Province were analyzed using the Luminex HLA sequence-specific oligonucleotide method with a WAKFlow HLA typing kit. A total of 13 alleles were detected at the HLA-DRB1 locus. HLA-DRB1*09 was the most common allele (22.52%), followed by DRB1*08 and DRB1*15 (11.07%), and DRB1*12 and DRB1*04 (10.69%). These data were compared with the results obtained for 10 other ethnic groups living in other regions as well as to Han groups using neighbor-joining dendrograms and principal component analysis. The results showed that the Tujia population has a close genetic relationship with the Middle Han population at the HLA-DRB1 locus. This information will be useful for HLA-DRB1-linked disease-association studies.

Annexin A5 anticoagulant activity in children with systemic lupus erythematosus and the association with antibodies to domain I of β2-glycoprotein I

Children with systemic lupus erythematosus (SLE) have a high prevalence of antiphospholipid (aPL) antibodies and are at increased risk for aPL-related thrombosis. We investigated the association between annexin A5 anticoagulant activity and antibodies to the domain I portion of β2-glycoprotein I (anti-DI antibodies), and propose a potential mechanism for the pathogenesis of aPL-related thrombosis. Using samples from 183 children with SLE collected during the Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, we examined resistance to the anticoagulant effects of annexin A5, using the annexin A5 resistance (A5R) assay, and evaluated for anti-DI IgG antibodies. Children with SLE had higher frequency of anti-D1 antibodies (p = 0.014) and significantly reduced A5R compared to pediatric controls: mean A5R = 172 ± 30% versus 242 ± 32% (p < 0.0001). Children with SLE and positive anti-DI antibodies had significantly lower mean A5R levels compared to those with negative anti-DI antibodies: mean A5R = 155 ± 24% versus 177 ± 30% (p < 0.0001). In multivariate analysis, anti-DI antibodies (p = 0.013) and lupus anticoagulant (LA) (p = 0.036) were both independently associated with reduced A5R. Children with SLE have significantly reduced annexin A5 anticoagulant activity that is associated with the presence of LA and anti-DI antibodies.

Viewing dynamic interactions of proteins and a model lipid membrane with atomic force microscopy

The information covered in this chapter will present a model homogenous membrane preparation technique and dynamic imaging procedure that can be successfully applied to more than one type of lipid study and atomic force microscope (AFM) instrument setup. The basic procedural steps have been used with an Asylum Research MFP-3D BIO and the Bruker (formerly, Veeco) BioScope. The AFM imaging protocol has been supplemented by procedures (not to be presented in this chapter) of ellipsometry, standardized western blotting, and dot-blots to verify appropriate purity and activity of all experimental molecular components; excellent purity and activity level of the lipids, proteins, and drug(s) greatly influence the success of imaging experiments in the scanning probe microscopy field. The major goal of the chapter is to provide detailed procedures for sample preparation and operation of the Asylum Research MFP-3D BIO AFM. In addition, one should be cognizant that our comprehensive description in the use of the MFP-3D BIO's functions for successful image acquisitions and analyses is greatly enhanced by Asylum Research's (AR's) accompanying extensive manual(s), technical notes, and AR's users forum. Ultimately, the stepwise protocol and information will allow novice personnel to begin acquiring quality images for processing and analysis with minimal supervision.

First Report of Ralstonia solanacearum Causing Bacterial Wilt of Yacon in China

Yacon (Smallanthus sonchifolius) is an important cash crop in Yunnan Province, China. In 2003, yacon was introduced to Yunnan province as a novelty root crop and as an experimental source of natural sugars; now more than 15 provinces cultivate the crop. Yunnan is one of the major yacon producing areas of China, with up to 10,000 ha yielding up to 50,000 t of yacon, which is nearly half of the production in China. In April and May 2010, bacterial wilt of yacon was observed in the fields of Lion Mountain of Wuding County, Yunnan Province, China. In 2011, the disease occurred in approximately 1 ha of yacon, resulting in 10% crop loss in that area. The initial symptoms observed were irregular, black, necrotic lesions on leaf margins. After 4 to 7 days, leaves became totally necrotic, plants wilted, and black stripes were observed on plant stems. Within 2 to 3 weeks, more than 70% of leaves within the crop were wilted. Subsequently, the plants died and stems became brittle. When dead plants were pulled from the soil, tubers were found to have turned black. When diseased stems and/or petioles were cut with a sterile sharp knife or razor blade, bacterial ooze appeared on the cut ends. High populations of morphologically uniform bacteria were isolated from the diseased plants by conventional methods. When cultured on TZC (2,3,5-Triphenylte tetrazolium chloride) agar medium (3), colonies were large, elevated, fluidal, and entirely white with a pale red center. The isolated bacterium was gram-negative, grew aerobically, and did not form endospores. The cells were 0.5 to 0.7 × 1.5 to 2.0 μm and nonencapsulated. Ralstonia solanacearum was identified and confirmed as the pathogen on the basis of morphological and physiological characteristics, pathogenicity test, and 16S rDNA sequence analysis (1,4). The nucleotide sequence is available in GenBank (Accession No. HQ176322.1). The pathogenic strain belonged to race 1 and biovar 3 according to the pathogenicity and carbohydrate utilization tests (2). Koch's postulates were tested in the greenhouse, with 10 plants inoculated per species. Plants were inoculated with 15 μl of cell suspension containing 10⁶ to 10⁷ CFU ml^-1 deposited into the third axilla with a capillary tube. The bacteria could infect tomato, pepper, tobacco, potato, common sage (Salvia dugesii Fernald), and patchouli, and caused typical symptoms of wilt and black lesions, but could not infect leaves of swamp mahogany (Eucalyptus robusta Smith), stramonium (Dature stramonium Datura L.), ginger, or maize. To our knowledge, this is the first report of yacon as a host of R. solanacearum. Since the pathogen has a wide host range, monitoring of the vegetation in and around yacon fields should be implemented as a mandatory management measure to prevent disease spread. References: (1) C. A. Boucher et al. J. Bacteriol. 169:5626, 1987. (2) A. C. Hayward. J. Appl. Bacteriol. 27:265, 1964. (3) A. Kelman. Phytopathology 44:693, 1954. (4) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.

Annexin A2 binds to endosomes following organelle destabilization by particulate wear debris

Endosomal functions are contingent on the integrity of the organelle-limiting membrane, whose disruption induces inflammation and cell death. Here we show that phagocytosis of ultrahigh molecular weight polyethylene particles induces damage to the endosomal-limiting membrane and results in the leakage of cathepsins into the cytosol and NLRP3-inflammasome activation. Annexin A2 recruitment to damaged organelles is shown by two-dimensional DIGE protein profiling, endosomal fractionation, confocal analysis of endogenous and annexin A2-GFP transfected cells, and immunogold labelling. Binding experiments, using fluorescent liposomes, confirms annexin A2 recruitment to endosomes containing phagocytosed polyethylene particles. Finally, an increase in cytosolic cathepsins, NLRP3-inflammasome activation, and IL-1 production is seen in dendritic cells from annexin A2-null mice, following exposure to polyethylene particles. Together, the results indicate a functional role of annexin A2 binding to endosomal membranes following organelle destabilization.

Insights into the pathophysiology of the antiphospholipid syndrome provided by atomic force microscopy

The antiphospholipid syndrome (APS) is an enigmatic autoimmune disorder in which patients present with thrombosis and/or recurrent pregnancy losses together with laboratory evidence for the presence of autoantibodies in the blood that recognize proteins that bind to anionic phospholipids - the most important of which is β(2)-glycoprotein I (β(2)GPI). Earlier, we hypothesized that the clinical manifestations arise from antibody-induced disruption of a two-dimensional anticoagulant crystal shield, composed of annexin A5, present on placental trophoblast plasma membranes. Accordingly, we reasoned that a high resolution imaging technology, such as atomic force microscopy could be used to investigate such molecular interactions at high resolution in a non-fixed hydrated environment. This review will focus on the contribution of this technique to the elucidation of the mechanism of APS.

Hydroxychloroquine reduces binding of antiphospholipid antibodies to syncytiotrophoblasts and restores annexin A5 expression

OBJECTIVE

Antibody-mediated disruption of the annexin A5 anticoagulant shield has been posited to be a thrombogenic mechanism in the antiphospholipid syndrome. We recently showed that the antimalarial drug, hydroxychloroquine, dissociates antiphospholipid immune complexes and restores annexin A5 binding to planar phospholipid bilayer. Using quantitative immunoassays, we demonstrated similar effects on BeWo trophoblasts. We therefore, investigated the effects of the drug on localization of annexin A5 in primary cultures of human placental syncytiotrophoblasts.

STUDY DESIGN

Laser confocal microscopy with computer-based morphometric analysis was used to localize annexin A5 and antiphospholipid antibodies on syncytiotrophoblasts exposed to polyclonal and monoclonal antiphospholipid and control immunoglobulin-Gs.

RESULTS

Hydroxychloroquine reversed the effects of the antiphospholipid antibodies on the syncytiotrophoblasts by markedly reducing immunoglobulin-G binding and restoring annexin A5 expression.

CONCLUSION

These results provide the first morphologic evidence for this effect of hydroxychloroquine on human placental syncytiotrophoblasts and support the possibility of novel treatments that target antiphospholipid antibody binding.

Resistance to annexin A5 anticoagulant activity in women with histories for obstetric antiphospholipid syndrome

OBJECTIVE

The objective of the study was to investigate whether resistance to annexin A5 anticoagulant activity (AnxA5) occurs in women with histories for obstetric complications of antiphospholipid syndrome (Obs-APS) and whether this correlates with antibody recognition of domain 1 of β2-glycoprotein.

STUDY DESIGN

One hundred thirty-six women with antiphospholipid antibodies, including 70 with histories for Obs-APS and 30 controls, were investigated.

RESULTS

Women with Obs-APS showed resistance to AnxA5 activity (median, 216%; range, 130-282% vs controls; median, 247%; range, 217-283%; P < .0001) and elevated levels of anti-domain I immunoglobulin (Ig) G (optical density: median, 0.056; range, 0.021-0.489 vs median, 0.042; range, 0.020-0.323; P = .002). Those in the lowest tertile of AnxA5 anticoagulant ratios had an odds ratio for Obs-APS of 58.0 (95% confidence interval, 3.3-1021.5). There was an inverse correlation between levels of annexin A5 anticoagulant activity and anti-domain I IgG.

CONCLUSION

Resistance to AnxA5 anticoagulant activity is associated with antibody recognition of domain I of β2-glycoprotein I and identifies a subset of women with histories for Obs-APS.

Association of SCD1 and DGAT1 SNPs with the intramuscular fat traits in Chinese Simmental cattle and their distribution in eight Chinese cattle breeds

Intramuscular fat (IMF) is a key parameter for evaluation of nutritional quality of beef, with its endogenous synthesis regulated by stearoyl CoA desaturase (SCD1) and diacylglycerol-acyl transferase 1 (DGAT1) genes in cattle. The object of this research was to evaluate the effect of SCD1 and DGAT1 polymorphisms on IMF trait in beef cattle and to estimate the frequency distribution of SNPs in the two genes in Chinese cattle populations. The SCD1 and DGAT1 polymorphisms were detected by PCR-single strand conformation polymorphism (PCR-SSCP) method in Chinese Simmental cattle and their associations with IMF traits were analyzed using the general linear model (GLM). The frequency distribution of SNPs in SCD1 and DGAT1 genes were detected by PCR-SSCP method and analyzed in seven other cattle populations. The results showed significant associations of SNPs SCD1-878, SCD1-762, and DGAT1 10433 and 10434 with IMF (%) and shearing force values (SFV; kg) in Chinese Simmental cattle. A haplotype combining SCD1-878C, SCD1-762T, and DGAT1 10433 and 10434-GC had the highest IMF, marbling score and shearing force. The polymorphic investigation indicated that the frequency of SCD1-878C or SCD1-762T was significantly higher in Chinese southern cattle (Leiqiong, Yunnan High pump, BMY or Minnan Cattle) than in Chinese northern cattle (Chinese Simmental, Luxi Cattle, Bohai Black or Chinese Holstein), while the frequency of DGAT1 10433 and 10434-GC in Chinese indigenous breed (Leiqiong, Yunnan High pump, BMY, Luxi Cattle, Bohai Black, or Minnan Cattle) was significantly lower than breeds with imported blood (Chinese Simmental or Chinese Holstein). These findings demonstrated that both the SCD1 and DGAT1 SNPs were prospect genetic markers for IMF traits, and the SCD1 SNPs could be used as a genetic marker for southern or northern blood in Chinese cattle.

Resistance to annexin A5 anticoagulant activity: a thrombogenic mechanism for the antiphospholipid syndrome

The phospholipid binding protein, annexin A5 (AnxA5), has potent anticoagulant properties that result from its forming 2-dimensional crystals over phospholipids, blocking the availability of the phospholipids for critical coagulation enzyme reactions. This article reviews the evidence that antiphospholipid antibodies can disrupt this anticoagulant shield and unmask thrombogenic anionic phospholipids, which may thereby contribute to thrombosis in patients with the antiphospholipid syndrome (APS). This mechanism for thrombosis in APS can be monitored with coagulation assays for resistance to anticoagulant activity of AnxA5.

A low molecular weight polysaccharide isolated from Agaricus blazei suppresses tumor growth and angiogenesis in vivo

Previous studies indicated that the low molecular weight polysaccharide extracts from Agaricus blazei are potential antitumor agents or adjuvant in tumor treatment. In this study, we investigated the antitumor activity of LMPAB, a low molecular weight polysaccharide isolated from Agaricus blazei, and the molecular mechanisms of its antitumor activity. The antitumor effect of LMPAB was examined using mouse sarcoma 180 (S180) xenograft models. Antiangiogenic effect of LMPAB was determined by chicken embryo chorioallantoic membrane (CAM) angiogenesis and Matrigel-induced neovascularization in vivo models. The mRNA and protein levels of vascular endothelial growth factor (VEGF) were assessed using real-time reverse transcription-polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assays. Tumor inhibitory rates in the S180 xenograft models were 9.7, 23.9, and 33.0%, respectively, after administration of LMPAB at dose of 50, 100, and 200 mg/kg/day for 2 weeks. LMPAB also inhibited angiogenesis in the CAM model and Matrigel-induced neovascularization in C57BL/6 mice. The mRNA and protein levels of VEGF in tumor tissues were significantly down-regulated in the BALB/c mice received LMPAB treatment. Furthermore, significant down-regulation of serum VEGF levels was also observed in the mice. Our data suggest that LMPAB might be a promising agent for tumor therapy, and the antitumor and antiangiogenic effects of LMPAB may be related with down-regulation of VEGF.

Primary malignant fibrous histiocytoma of the thyroid

AIMS AND METHODS

To study the clinical features, diagnosis, and treatment of primary malignant fibrous histiocytoma of the thyroid (MFH-T). Treatment and outcome were analyzed retrospectively in a consecutive series of 12 patients with primary MFH-T treated at the Cancer Hospital of the Chinese Academy of Medical Sciences from 1987 to 2007.

RESULTS

All 12 patients underwent surgery; surgery alone was used in four patients. Five patients were given post-operative radiotherapy, and one patient was given pre-operative radiotherapy. Two patients were given post-operative chemotherapy. Five patients had locoregional recurrence, and five had distant metastases in follow-up. Median survival was 9 months. One patient is alive, and has no evidence of disease. Six patients died six months after treatment, and the other four patients died in 10, 14, 18, and 24 months after treatment, respectively. Nine patients died of the disease, and one patient died of cerebral hemorrhage after treatment.

CONCLUSION

Primary MFH-T is very rare and has a poor prognosis. Although surgical resection of MFH-T is the treatment of choice in MFH-T, the results are unsatisfactory.

Theoretical investigations of the EPR parameters for Cr3+ and Mn4+ ions in PbTiO3 crystals

The complete high-order perturbation formulas of EPR parameters (g factors g( parallel), g( perpendicular) and zero-field splitting D), containing the crystal-field (CF) mechanism and charge-transfer (CT) mechanism (the latter is omitted in crystal-field theory which is often used to study the EPR parameters), are established from a cluster approach for 3d3 ions in tetragonal octahedral sites. According to the calculations based on these formulas, the EPR parameters g( parallel), g( perpendicular) and zero-field splitting D for Cr3+ and Mn4+ ions in PbTiO3 crystals are explained reasonably. The calculations show that (i) the sign of g-shift Deltag(i)(CT) (=g(i)-g(s), where g(s)=2.0023 is free-electron value and i= parallel and perpendicular) in CT mechanism is opposite to, but that of D(CT) is the same as, the corresponding signs in the CF mechanism and (ii) the relative importance of CT mechanism for the high valence state 3d3 ion (e.g., Mn4+) is large and so the contributions to EPR parameters from CT mechanism should be taken into account. The different sign of splitting D and the different defect structure for Cr3+ and Mn4+ impurity centers in PbTiO3 crystals are also suggested from the calculations. The results are discussed.

Investigations of the EPR zero-field splitting and the defect structure for Mn(2+) and Fe(3+) ions in anatase crystals

The EPR zero-field splittings D of Mn(2+) and Fe(3+) ions in anatase crystals at room and low temperatures are calculated from the high-order perturbation formula of zero-field splitting D for 3d(5) ions in tetragonal symmetry based on the dominant spin-orbit coupling mechanism. The calculated results are consistent with the observed values. From the calculations, Mn(2+) and Fe(3+) ions are suggested to substitute for Ti(4+) ions in anatase (in the previous paper, Mn(2+) ion was suggested at an interstitial site rather than substitutional site) and the defect structures (characterized mainly by the local oxygen parameter u) for both tetragonal Mn(2+) and Fe(3+) impurity centers are estimated. The different zero-field splitting at room and low temperatures are due mainly to the change of local oxygen parameter u with the temperature. These results are discussed.

Theoretical calculation of EPR g factors for Ni(3+) ion at the interstitial site of SnO(2) crystal

The EPR g factors g(x), g(y) and g(z) for Ni(3+) ion at the interstitial site in the rutile-type SnO(2) crystal are calculated from the second-order perturbation formulas of g factors based on the cluster approach for 3d(7) ion in rhombic symmetry. The calculated results are in agreement with the experimental values. The local lattice distortion induced by the impurity Ni(3+) at the interstitial site of SnO(2) is also estimated from the calculations. These results are discussed.

Enhanced susceptibility of adriamycin-treated human renal cell carcinoma cells to lysis by peripheral blood lymphocytes and tumor infiltrating lymphocytes

Previous studies indicated that the anticancer agent adriamycin (ADR) could induce activation of cytotoxic T lymphocytes (CTL) and natural killer cells. In this study, we investigated the effect of ADR on the susceptibility of human renal cell carcinoma (RCC) cells to lysis by peripheral blood lymphocytes (PBL) and tumor infiltrating lymphocytes (TIL). Treatment of human RCC cell line ACHN and freshly derived RCC cells with ADR at 1 microg/ml or more for 3 h significantly enhanced their susceptibility to lysis by PBL (P<0.05). This ADR-induced enhancement of susceptibility of RCC cells to lysis by PBL was also observed when freshly derived TIL were used as effector cells (P<0.05). ADR up-regulated the expression of leukocyte function-associated antigen-3 (LFA-3) and intercellular adhesion molecule-1 (ICAM-1), which are critical in the binding and killing of CTL against cancer cells. Of the five fresh RCC cell cultures treated with ADR, LFA-3 was increased in all and ICAM-1 was increased in three of them, respectively (P<0.05). Up-regulation of LFA-3 and ICAM-1 was also observed in ACHN cells treated with two derivatives of ADR, epirubicin and pirarubicin. ADR further significantly increased the bindings of PBL to RCC cells (P<0.05). These findings suggest that treatment of RCC patients with low doses of ADR may sensitize the RCC cells to killing by PBL and TIL and may be a novel immunotherapeutic modality for the treatment of drug-resistant and/or immune-resistant RCC. The inducing of LFA-3 and ICAM-1 by ADR may be involved in the enhancement of susceptibility of PBL and TIL-mediated cytolysis in human RCC cells.

[Investigation of optical and EPR spectra of ZnO : V3+ crystal]

In the present paper, the 45 X 45 energy matrix of the 3d2 ions in trigonal symmetry with the strong-field-coupling mechanism is established. The forty-five optical energy levels and five EPR parameters (including the zero-field splitting D, g factors g//, g perpendicular and hyperfine structure constants A//, A perpendicular) of ZnO : V3+ cryst are calculated from the diagonalization of this complete energy matrix. The calculated results are in agreement with the observed values. Based on the calculation, it was found that the local structure of V3+ impurity center is different from the corresponding structure in the host crystal, i. e., the V3+ ion in ZnO does not occupy the exact Zn2+ site, but is displaced by DeltaZ approximately 0.003 nm along the c3 axis. The reasonableness of these results is discussed.

Investigations of the EPR g factors and hyperfine structure constants for two trigonal Co2+ centers in Al2O3 crystals

The EPR g factors gparallel, gperpendicular and the hyperfine structure constants Aparallel, Aperpendicular for two trigonal Co2+ centers (i.e. Co2+(I) center at the substitutional site and Co2+(II) center at the interstitial site) in Al2O3 crystals are calculated from the second-order perturbation formulas based on the cluster approach. In these formulas, the contributions to EPR parameters from both the spin-orbit coupling parameter of central 3dn ion and that of ligand are included. The calculated results are in reasonable agreement with the observed values. Based on the calculations, the defect structures of both Co2+ centers in Al2O3 crystals are obtained and the negative sign of Aparallel for Co2+(I) center is suggested. The results are discussed.

Monoclonal antibody to tumor necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL-R2) induces apoptosis in primary renal cell carcinoma cells in vitro and inhibits tumor growth in vivo

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis in a variety of tumor cells through two of its receptors: TRAIL-R1 and TRAIL-R2. We investigate the susceptibility of human renal cell carcinoma (RCC) cells to TRM-1 and HGS-ETR2, 2 human monoclonal agonistic antibodies specific for TRAIL-R1 and TRAIL-R2, respectively. HGS-ETR2 effectively induced apoptotic cell death in 10 of 11 cell cultures, including 2 human RCC cell lines and 9 human primary RCC cell cultures, with a more pronounced effect after preincubation with anti-human IgG Fc. In contrast, TRM-1 was effective in only 1 primary RCC cell culture. The increased effectiveness of HGS-ETR2 for inducing cell death might have been affected by differences in the cell-surface expression of the 2 TRAIL receptors, namely that TRAIL-R2 but not TRAIL-R1 was frequently expressed in most of the RCC cells tested. The activities of caspase-9, -8, -6, and -3 were increased with HGS-ETR2-induced apoptosis, and cell death could be blocked by specific caspase inhibitors for caspase-9, -8, and -3, and the general caspase inhibitor. In vivo administration of HGS-ETR2 with or without cross-linker significantly suppressed tumor growth of subcutaneously inoculated human RCC xenografts in immunodeficient mice. These results suggest the potential utility of TRAIL-R2 antibody as a novel therapeutic agent in RCC.

Studies of the trigonal field parameters and g factors for magnetic semiconductor NaCrS2

The trigonal field parameters v and v' of magnetic semiconductor NaCrS2 are calculated from the superposition model, and its g factors g parallel and g perpendicular are calculated from the high-order perturbation formulas of 3d3 ions in trigonal symmetry obtained by the one and two spin-orbit coupling parameter models. These calculations are based on the structural data of NaCrS2 crystal. The calculated results suggest that the superposition model is effective to the analyses of the low-symmetry field parameters of 3dn ions in crystals and that the two spin-orbit coupling parameter model (where the contributions from both the spin-orbit coupling parameter of 3dn ion and that of ligand are considered) is preferable to the one spin-orbit coupling parameter model (in which the contribution from only the spin-orbit coupling parameter of 3dn ion is considered) in the explanations of g factors in the cases that ligands have large spin-orbit coupling parameter in 3dn clusters.

Correlation between antiphospholipid antibodies that recognize domain I of beta2-glycoprotein I and a reduction in the anticoagulant activity of annexin A5

The paradoxical correlation between thrombosis and the lupus anticoagulant (LAC) effect is an enigmatic feature of the antiphospholipid (aPL) syndrome. The Dutch authors previously reported that thrombosis-related anti-beta2-glycoprotein I (beta2GPI) antibodies recognize domain I and cause LAC. The American authors reported that aPLs disrupt an anticoagulant annexin A5 (AnxA5) crystal shield. We investigated whether antidomain I antibodies correlate with disruption of AnxA5-anticoagulant activity. We studied a well-characterized group of 33 patients including subgroups with beta2GPI-dependent LAC that recognize domain I (n=11), with beta2GPI-independent LAC (n=12), and lacking LAC (n=10). The effects on AnxA5-anticoagulant activity were determined with an AnxA5 resistance assay that measures coagulation times with and without AnxA5. Patients with beta2GPI-dependent LAC (group A, all with thrombosis) had significantly lower AnxA5-anticoagulant ratios than those with beta2GPI-independent LAC (group B, thrombosis n=4; 157.8% versus 235.6%, P<.001) and those without LAC (group C, thrombosis n=2; 157.8% versus 232.5%, P<.001). There was no difference in the ratios between groups B and C (P=.92). Plasmas with beta2GPI-dependent LAC that recognize domain I displayed significantly increased AnxA5 resistance, suggesting that specifically anti-beta2GPI antibodies compete with AnxA5 for anionic phospholipids. These results are consistent with a model in which aPL antibodies may promote thrombosis by interfering with the anticoagulant activity of AnxA5.

Analysis of circulating annexin A5 parameters during pregnancy: absence of differences between women with recurrent spontaneous pregnancy losses and controls

OBJECTIVE

We investigated whether levels of annexin A5 (AnxA5), AnxA5 anticoagulant activity and binding, and anti-AnxA5 antibodies might be altered in women with previous histories of recurrent spontaneous pregnancy losses (RSPL) when tested during pregnancy.

STUDY DESIGN

Ninety pregnant women with histories of 3 or more RSPL (cases) and 150 women without adverse pregnancy histories (controls) were assayed for these AnxA5 parameters.

RESULTS

There were no significant differences between cases and controls in AnxA5 levels (median, 23.1 ng/mL [range, 2.1-201.1 ng/mL] vs 19.7 ng/mL [2.1-151.5 ng/mL]; P = .20), AnxA5 anticoagulant activity (183% [101%-236%] vs 168% [128%-256%]; P = .39) and binding (6.0 ng/aliquot PL [2.1-19.5 ng/aliquot PL) vs 6.1 ng/aliquot PL [1.6-16.8 ng/aliquot PL]; P = .72), and anti-AnxA5 antibody levels.

CONCLUSIONS

AnxA5 parameters do not distinguish between cases and controls when tested during pregnancy. The pregnant state itself appears to be associated with altered levels of AnxA5 parameters.