Key pathway to prevent the collapse of femoral head in osteonecrosis

OBJECTIVE

Osteonecrosis of the femoral head (ONFH) is a multifactorial disease, with unclear pathogenesis. The collapse of the femoral head is an important turning point in ONFH, especially for young patients. Many methods have been proposed, but the best treatment lacks consensus among orthopedic surgeons. Thus, understanding the collapse mechanism of the femoral head in ONFH is the key to a successful outcome of joint preservation. This review aims to provide an update of the collapse mechanism of the femoral head in ONFH and to focus on the most appropriate therapeutic strategies to adopt in clinical practice.

MATERIALS AND METHODS

We reviewed the international literature to identify studies focusing on ONFH and therapeutic options. PubMed, Medline and Cochrane Library databases were searched for English language papers.

RESULTS

An imbalance between bone resorption and bone formation as well as stress distribution on insufficient trabecular bone may be the most important collapse mechanism in ONFH.

CONCLUSIONS

Treatment to avoid femoral head collapse should focus on local effective mechanical support with modification of bone remodeling in the femoral head.

Nuclear ULK1 promotes cell death in response to oxidative stress through PARP1

Reactive oxygen species (ROS) may cause cellular damage and oxidative stress-induced cell death. Autophagy, an evolutionarily conserved intracellular catabolic process, is executed by autophagy (ATG) proteins, including the autophagy initiation kinase Unc-51-like kinase (ULK1)/ATG1. Although autophagy has been implicated to have both cytoprotective and cytotoxic roles in the response to ROS, the role of individual ATG proteins, including ULK1, remains poorly characterized. In this study, we demonstrate that ULK1 sensitizes cells to necrotic cell death induced by hydrogen peroxide (H2O2). Moreover, we demonstrate that ULK1 localizes to the nucleus and regulates the activity of the DNA damage repair protein poly (ADP-ribose) polymerase 1 (PARP1) in a kinase-dependent manner. By enhancing PARP1 activity, ULK1 contributes to ATP depletion and death of H2O2-treated cells. Our study provides the first evidence of an autophagy-independent prodeath role for nuclear ULK1 in response to ROS-induced damage. On the basis of our data, we propose that the subcellular distribution of ULK1 has an important role in deciding whether a cell lives or dies on exposure to adverse environmental or intracellular conditions.

Effect of anesthesia combined with intercostal nerve block on analgesia for esophageal cancer after operation

OBJECTIVE

To discuss the effect of combined with intercostal nerve block on analgesia for esophageal cacer after operation.

PATIENTS AND METHODS

The total of 80 patients with esophageal cancer as the research object in our hospital from June 2012 to June 2013 were randomly grouped as epidural anesthesia (control group) and general anesthesia and intercostal nerve block combined with application (observation group), whose prognoses were compared.

RESULTS

We compared the control group at each time point and the observation group at time T1-T4 with T0. Mean arterial pressure (MAP) had significantly lower performance (mean p < 0.05); at T4, central venus pressure (CVP) of the control group improved significantly (mean p < 0.05), MAP value of the observation group at T3, T4 was significantly lowerthan the control group (mean p < 0.05). The degree of pain 24-48 h after operation of the observation group was lower than the control group, and the difference was statistically significant (p < 0.05).

CONCLUSIONS

Application of general anesthesia combined with intercostal nerve block analgesia in esophageal surgery can obtain satisfactory postoperative analgesia.

Mitochondria-dependent apoptogenic activity of the aqueous root extract of Croton membranaceus against human BPH-1 cells

Croton membranaceus aqueous root extract (CMARE) is among the widely used phytotherapeutics in Ghana for the management of benign prostatic hyperplasia (BPH) and prostate cancer. However, the mechanism of action of CMARE remains to be elucidated. This study aimed to establish whether apoptosis is involved in the antiproliferative effect of CMARE on human BPH-1 cells. We determined the effect of treatment with 0, 1, 3, and 5 mg/mL CMARE for 24, 48, and 72 h on the viability and morphology of BPH-1 cells using the MMT assay and phase-contrast microscopy, respectively. We examined the apoptosis-inducing effects of CMARE after 48 h at the cellular level using Hoescht 33258 and JC-1 dye staining and flow cytometry analysis. We performed reverse transcription polymerase chain reaction and Western blotting to confirm the apoptotic effects of CMARE at the molecular level. CMARE induced a significant dose-dependent inhibition in the proliferation of BPH-1 cells (P < 0.05) and an alteration in their morphology and a reduction their density. Furthermore, CMARE induced dose-dependent staining of the nuclear chromatin, significant DNA fragmentation with G₀/G₁ sub-diploid cells (P < 0.01), and loss of the mitochondrial membrane potential in the treated cells compared to the controls after 48 h (P < 0.01). Additionally, while CMARE induced a significant upregulation of the mRNA and protein levels of Bax, those of Bcl2 did not change significantly. Therefore, induction of mitochondria-dependent apoptosis of BPH-1 cells may be a possible mechanism of action of CMARE.

Elevated expression of CX3C chemokine receptor 1 mediates recruitment of T cells into bone marrow of patients with acquired aplastic anaemia

OBJECTIVE

Acquired aplastic anaemia (AA) is a T-cell-mediated, organ-specific autoimmune disease characterized by haematopoietic stem cell destruction in the bone marrow. The exact molecular mechanism of T-cell trafficking into the bone marrow is unclear in AA. Very late activation antigen-4 (VLA-4) and CX3C chemokine receptor 1 (CX3CR1) play active roles in many autoimmune diseases. Therefore, we investigated whether VLA-4 and CX3CR1 also contribute to T-cell migration into the bone marrow in acquired AA.

DESIGN, SETTING AND SUBJECTS

Expression levels of CX3CR1 and VLA-4 and their ligands [fractalkine (CX3CL1) and vascular cell adhesion molecule-1 (VCAM-1)] were examined in 63 patients with AA and 21 healthy control subjects. T-cell chemotaxis and adhesion were analysed in 17 patients with severe AA. We also prospectively evaluated the expression pattern of CX3CR1 during treatment with antithymocyte globulin plus cyclosporine in 11 patients with severe AA.

RESULTS

The proportion of peripheral and bone marrow CD4(+) and CD8(+) T cells expressing CX3CR1 and the level of CX3CL1 was increased in patients with AA. However, there was no significant difference in VLA-4 expression or VCAM-1 levels. Functional studies demonstrated that chemotaxis towards autologous bone marrow plasma or soluble CX3CL1 was significantly higher in T cells from AA patients and could be blocked by CX3CR1 inhibitors. CX3CR1-mediated T-cell adhesion was also upregulated in these patients. The expression of CX3CR1 was associated with the efficacy of immunosuppressive therapy.

CONCLUSION

The present findings demonstrate that CX3CR1 plays a pivotal role in recruitment of T cells into the bone marrow in acquired AA and is a potential therapeutic target for treatment of this disorder.

First Report of the Root-Knot Nematode Meloidogyne enterolobii Infecting Jujube in China

Jujube (Ziziphus jujuba Mill.) is an economically-important fruit crop grown in Europe, Australia, and southern/eastern Asia. In China, it is often called red date and the fruit is used in traditional Chinese herbal medicine and wine. In February 2014, jujube plants growing in a sandy soil in Sanya, Hainan Province, China, were observed exhibiting symptoms of decline, including stunting, wilting, and no flowering or fruit set. Roots systems of sick plants (n = 20) had many galls, the typical symptoms of root-knot nematode infection, and the incidence of infection was 100%. These galls were formed in the primary, secondary, and tertiary roots. Meloidogyne spp. females and egg masses were dissected from the symptomatic roots. Each root contained about 72 females on average (n = 20). The perineal patterns of females (n = 10) were oval shaped with moderate to high dorsal arches and mostly lacking obvious lateral lines. Second-stage juveniles (n = 20) had large and triangular lateral lips and broad, bluntly rounded tail tips. These morphological characteristics are the same as those for Meloidogyne enterolobii Yang & Eisenback 1983 (5). Identification was further confirmed after DNA extraction from 12 nematodes. Part of the rDNA spanning the internal transcribed spacer (ITS) 1, 5.8S gene, and ITS2 was amplified with primers V5367/26S (TTGATTACGTCCCTGCCCTTT/TTTCACTCGCCGTTACTAAGG) (4). A 764-bp fragment was amplified, which was 100% identical to sequences of M. enterolobii (GenBank Accession Nos. KJ146863, KF418369, JQ082448, and JX024149) in GenBank. Species identification was confirmed by using PCR to amplify mitochondrial (mt) DNA and rDNA intergenic spacers (IGS) 2 with primers C2F3/1108 (GGTCAATGTTCAGAAATTTGTGG/TACCTTTGACCAATCACGCT) (3) and M. enterolobii specific primers Me-F/Me-R (AACTTTTGTGAAAGTGCCGCTG/TCAGTTCAGGCAGGATCAACC), respectively (2). The PCR products were approximately 700 bp for mtDNA and 200 bp for rDNA-IGS2, which were also identical to those previously reported for M. enterolobii (2,3). M. enterolobii is considered as one of the most damaging root-knot nematode species due to its wide host range, high reproduction rate, and ability to overcome the resistance genes (Mi-1, Mh, Mir1, N, Tabasco, and Rk) in several crops (1). It is reported that over 20 plant species from eight families (Annonaceae, Apiaceae, Cucurbitaceae, Convolvulaceae, Fabaceae, Marantaceae, Myrtaceae, and Solanaceae) in China are hosts for M. enterolobii. To our knowledge, this is the first report of jujube as a host of M. enterolobii and the first record of M. enterolobii as a parasite of a plant in the family Rhamnaceae in China. References: (1) P. Castagnone-Sereno. Nematology 14:133, 2002. (2) H. Long et al. Acta Phytopathol. Sinica 36:109, 2006. (3) T. O. Powers and T. S. Harris. J. Nematol. 25:1, 1993. (4) T. C. Vrain et al. Fundam. Appl. Nematol. 15:565, 1992. (5) B. Yang and J. D. Eisenback. J. Nematol. 15:381, 1983.

Bone-cartilage interface crosstalk in osteoarthritis: potential pathways and future therapeutic strategies

Currently, osteoarthritis (OA) is considered a disease of the entire joint, which is not simply a process of wear and tear but rather abnormal remodelling and joint failure of an organ. The bone-cartilage interface is therefore a functioning synergistic unit, with a close physical association between subchondral bone and cartilage suggesting the existence of biochemical and molecular crosstalk across the OA interface. The crosstalk at the bone-cartilage interface may be elevated in OA in vivo and in vitro. Increased vascularisation and formation of microcracks associated with abnormal bone remodelling in joints during OA facilitate molecular transport from cartilage to bone and vice versa. Recent reports suggest that several critical signalling pathways and biological factors are key regulators and activate cellular and molecular processes in crosstalk among joint compartments. Therapeutic interventions including angiogenesis inhibitors, agonists/antagonists of molecules and drugs targeting bone remodelling are potential candidates for this interaction. This review summarised the premise for the presence of crosstalk in bone-cartilage interface as well as the current knowledge of the major signalling pathways and molecular interactions that regulate OA progression. A better understanding of crosstalk in bone-cartilage interface may lead to development of more effective strategies for treating OA patients.

Molecular cloning and expression analysis of the GNAS gene in pig and porcine fibroblast cells

The Alpha subunit of the stimulatory guanine nucleotide-binding protein (GNAS) is a complex imprinted gene. The major product of the GNAS gene is the α-subunit of the guanine nucleotide-binding protein (Gas), which plays a key role in multiple signal transduction pathways. Gas is required for the production of the receptor-stimulated intracellular cyclic adenosine monophosphate (cAMP). It has been demonstrated that an increase in the concentration of the intracellular second messenger cAMP promotes apoptosis in different tumor entities. Mutations of GNAS have also been identified in many tumors. This study aimed to investigate the expression pattern and the apoptosis effect in fibroblast cells for porcine GNAS. The results show that GNAS mRNA was detected in a wide range of tissues, especially in the longissimus dorsi muscle and thyroid gland. The developmental pattern of GNAS mRNA in the thyroid gland of Jinhua pigs was then examined; however, there was no significant difference (P > 0.05) among any of the stages. GNAS gene expression was relatively stable in the thyroid gland during the entire growth and development process. The developmental pattern of GNAS mRNA in the longissimus dorsi muscle was significantly different among the various developmental stages (P < 0.01). GNAS mRNA was strongly expressed at 60 days, 90 days, and 150 days after birth, whereas the expression level was very low during the embryo stages. Target RNA interference of GNAS in porcine fibroblast cells leads to lower mRNA expression of Bcl-2, Fas, and Caspase-3, which are recognized as apoptosis related markers.

Wide-scale pollen banking of ornamental plants through cryopreservation

BACKGROUND

Cryopreservation has been proved to be an efficient method for the long-term storage of pollen, based on our previous studies establishing cryo pollen banks for Camellia, Paeonia, and Prunus mume.

OBJECTIVE

In the present study, we aimed to extend and verify the applicability of the cryopreservation protocol for ornamental plants.

MATERIALS AND METHODS

71 species or cultivars from 19 families were cryopreserved using the established protocol.

RESULTS

Pollen from 60 species or cultivars (85% of those experimented on) retained viability after 1 year's cryopreservation; of these, 36 (51% of the total investigated) retained a sufficiently high germination capability compared with fresh pollen to enable longer term cryopreservation.

CONCLUSION

This study confirms that wide-scale pollen banking of ornamental plants is feasible.

Nuclear PRAS40 couples the Akt/mTORC1 signaling axis to the RPL11-HDM2-p53 nucleolar stress response pathway

The Ribosomal Protein (RP)-HDM2-p53 pathway has been shown to play key roles in oncogene-induced apoptosis and senescence, but the mechanism regulating this pathway remains elusive. The Proline-Rich Akt Substrate of 40 kDA (PRAS40) has recently been identified as a binding partner and inhibitor of the mechanistic Target of Rapamycin Complex 1 (mTORC1). Although other inhibitors of mTORC1 are known tumor suppressors, PRAS40 promotes cell survival and tumorigenesis. Here we demonstrate that Akt- and mTORC1-mediated phosphorylation of PRAS40 at T246 and S221, respectively, promotes nuclear-specific association of PRAS40 with Ribosomal Protein L11 (RPL11). Importantly, silencing of PRAS40 induces upregulation of p53 in a manner dependent upon RPL11. This effect is rescued by wild type PRAS40, but not by the RPL11 binding-null PRAS40 T246A mutant. We find that PRAS40 negatively regulates the RPL11-HDM2-p53 nucleolar stress response pathway and suppresses induction of p53-mediated cellular senescence. This work identifies nuclear PRAS40 as a dual-input signaling checkpoint that links cell growth and proliferation to inhibition of cellular senescence. These findings may help to explain the pro-tumorigenic effect of PRAS40 and identify the PRAS40-RPL11 complex as a promising target for p53-restorative anti-cancer drug discovery.

The delayed massive hemorrhage after gastrectomy in patients with gastric cancer: characteristics, management opinions and risk factors

AIMS

This study was designed to investigate the clinical features of delayed massive hemorrhage (DMH) after gastrectomy in patients with gastric cancer (GC).

METHODS

This study retrospectively reviewed 1536 GC patients with major gastrectomy between 1998 and 2011. Based on the time onset of postoperative bleeding, patients were divided into early postoperative hemorrhage (EPH), delayed massive hemorrhage (DMH), and no-bleeding groups. Postoperative mortality, bleeding treatment, and risk factors of hemorrhage were explored.

RESULTS

In sum, 15 (0.9%) patients suffered from DMH, with three (20%) dead cases. None of 18 (1.2%) patients with EPH died, but there were three dead cases in no-bleeding group. DMH had more extra-intestinal bleeding (P = 0.037) than EPH. Angiographic embolization was performed in 12 (80%) of DMH patients and successful in ten cases. Surgical procedures were applied in only two embolization-failed cases. Extended lymphadenectomy (P = 0.038), vascular skeletonization (P = 0.012) and advanced TNM stage (P < 0.001) were correlated with DMH.

CONCLUSIONS

DMH can be successfully managed with angiographic embolization, followed by alternative surgery. Extensive lymphadenectomy and vascular skeletonization should be discreetly performed during gastrectomy.

Association of autoantibody specificity and response to intravenous immunoglobulin G therapy in immune thrombocytopenia: a multicenter cohort study

BACKGROUND

Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder, in which platelet glycoprotein (GP)IIb-IIIa and GPIb-IX are the two most frequently targeted autoantigens. Our previous studies in animal models of ITP demonstrated that intravenous immunoglobulin G (IVIG) could protect against anti-GPIIb-IIIa autoantibody-mediated thrombocytopenia but failed to ameliorate ITP induced by most anti-GPIb-IX autoantibodies.

OBJECTIVES

The objective of this human study was to evaluate the association between the specificity of antiplatelet autoantibodies and response to IVIG treatment.

PATIENTS/METHODS

In this retrospective study, a cohort of 156 previously untreated adults with severe ITP who underwent IVIG therapy (0.4 g kg(-1)  day(-1) for 5 days) was analyzed. The primary outcome was response defined as platelet counts of ≥ 30 × 10(9)  L(-1) and a doubling of baseline counts within 7 days of dosing, and an absence of bleeding.

RESULTS AND CONCLUSIONS

Among the 66 patients with anti-GPIb-IX autoantibodies, only 24 (36.4%) achieved a response, as compared with 72 of 90 patients (80.0%) who were negative for anti-GPIb-IX autoantibodies (relative risk 2.2; 95% confidence interval 1.6-3.1). This study found no difference in response between patients with anti-GPIIb-IIIa autoantibodies (61.7%) and those without anti-GPIIb-IIIa autoantibodies (61.3%). Logistic regressions, including main effects and the interaction between these two autoantibodies, showed no influence of anti-GPIIb-IIIa autoantibodies on the effects of anti-GPIb-IX autoantibodies with regard to their association with IVIG response. Thus, in adults with ITP, the presence of anti-GPIb-IX autoantibodies is a predictive factor for poor response to IVIG treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01666795.

Identical Quality Assurance for Volumetric Modulated Arc Therapy in Elekta and Varian Machines

Volumetric modulated arc therapy (VMAT) has been adopted by many clinics for its higher delivery efficiency compared to conventional intensity modulated radiotherapy techniques. Currently, the quality assurance (QA) has remained a challenge in that no identical tests are available for accelerators from different vendors. This study is the first attempt to design identical QA tests for the VMAT technique for Varian and Elekta machines. Identical procedures testing MLC positions and movements, dose rate variations, and gantry positions and movement were created for both machines. These included picket fence (PF), dose rate vs. gantry speed (DRGS) and MLC speed vs. dose rate (MLCDR) tests. Deliverable plans for these tests were made with in-house software that was deliverable for linacs from two vendors (Elekta Synergy and Varian Trilogy). The electronic portal imaging device (EPID) was used for these tests. An automated analysis method was established and software was created to quantitatively evaluate the result. The systematic gap position and width errors from PF tests were within 0.5 mm. We evaluated the detectability of this program for introduced errors down to 0.2 mm. Linear relationships existed between the introduced errors and measured errors. In the DRGS test, 99.8% and 100.0% of the intensity deviations from expected profiles were less than 3% for the Synergy and Trilogy, respectively. For the MLCDR, the intensity deviations from expected profiles less than 3% were 100.0% for Synergy and 98.1% for Trilogy. Identical test series were created and implemented for VMAT accelerators from two vendors. Test results were reported from both accelerators. Comparable results were obtained from both vendors, enabling uniform criteria to be established for VMAT quality assurance.

Abstract P2-11-07: Proteins predictive of bone metastasis development in breast cancer patients

Background

Bone is the commonest site of metastasis in breast cancer and bone metastasis is associated with skeletal complications and reduced quality of life. Adjuvant use of zoledronic acid (ZA) has been explored to prevent or reduce development of bone metastases. In the large international AZURE trial (N = 3360), early stage (II/III) breast cancer patients were randomised to standard therapy (control arm) or to standard therapy + ZA. There is an unmet need for biomarkers to identify early stage patients at high risk of developing bone metastasis so that therapy can be appropriately targeted. We report a study using proteomics and primary tumour tissue microarrays (TMAs) from patients in the AZURE trial to address this need.

Methods

Bone- and lung-homed variants of the MDA-MB-231 cell line were compared to the parental (non-bone homing) cell type using proteomics (difference gel electrophoresis and mass spectrometry) to identify differentially regulated proteins for clinical validation using TMAs from the AZURE trial. Following characterisation on breast cancer TMAs of different grade, protein expression of candidate biomarkers on AZURE TMAs was assessed semi-quantitatively (low, medium, or high) based on immunohistochemical staining intensity. Statistical analysis investigated associations between protein expression, clinical variables (e.g. ER/PR/HER2 status) and time to local and distant recurrence events (updated to 59 months follow-up).

Results

Over 140 proteins were differentially expressed and two were chosen for validation based on fold change, biological relevance and antibody availability: Macrophage-capping protein (CAPG) and PDZ domain-containing protein GIPC1. Cox proportional hazards regression analysis of 378 AZURE breast tumour samples showed that patients who did not receive ZA were 4.5-fold more likely to develop bone-only metastasis (p = 0.006) if both proteins were highly expressed in the primary tumour (adjusted for systemic therapy plan, ER status, lymph node involvement, Table 1). This effect was not seen in patients who received ZA. Kaplan-Meier analysis indicated that the effect was not linked to menopausal status.

Discussion

We have identified two proteins expressed in primary breast tumours of patients which are significantly associated with subsequent development of bone-only metastases and appear to predict for benefit from ZA. Biologically, the two proteins are reported to be involved in cellular structures and signalling, and are implicated in cancers, but their association with breast cancer bone metastasis appears to be novel. Ongoing analysis will extend validation in a further AZURE TMA sample set. These proteins have potential as biomarkers to predict development of bone metastasis.

Table 1: Cox proportional hazards regressions for breast cancer patients with high expression of CAPG and GIPC1 protein in primary tumour cells ArmN (events)HR95% CIp OV691.4520.673-3.1330.342Any distant recurrenceC341.2110.542-2.7040.641 ZA351.2400.468-3.2870.665 OV313.0361.150-8.0170.025Skeletal and other distant metastasesC172.9721.119-7.8890.029 ZA140.9780.214-4.4700.977 OV214.4461.547-12.7800.006Skeletal metastases onlyC144.4491.545-12.8080.006 ZA71.0560.122-9.1540.961Arm: OV, Overall, n = 378; C, Control, n = 191; ZA, n = 187

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-11-07.

Basic science and clinical application of platelet-rich plasma for cartilage defects and osteoarthritis: a review

Cartilage defects (CDs) and the most common joint disease, osteoarthritis (OA), are characterized by degeneration of the articular cartilage that ultimately leads to joint destruction. Current treatment strategies are inadequate: none results in restoration of fully functional hyaline cartilage, for uncertain long-term prognosis. Tissue engineering of cartilage with auto-cartilage cells or appropriate mesenchymal stem cell (MSC)-derived cartilage cells is currently being investigated to search for new therapies. Platelet-rich plasma (PRP), an autologous source of factors obtained by centrifugation, possesses various functions. For culture of MSCs and cartilage cells, it might be substituted for fetal bovine serum (FBS) with high efficiency and safety. It enhances the regeneration of cartilage cells when added to cartilage tissue engineering constructs for repairing CDs and as regenerative injection therapy for OA. But challenges also remain. Some of the growth factors (GFs) present in PRP have negative effects on the OA joint. It is therefore unlikely that a mix of GFs some of which have negative effects in the OA joint, as present in PRP, will be of benefit in OA. Future directions of PRP application may concentrate on seeking an appropriate and innocuous agent like anti-VEGF antibody that can modulate and control the effect of PRP.

Competition between antiferromagnetism and ferromagnetism in Sr2RuO4 probed by Mn and Co doping

Spin-triplet superconductivity in Sr₂RuO₄ has attracted enormous interest. Like other unconventional superconductors, superconductivity in Sr₂RuO₄ is in close proximity to magnetic instability. Undoped Sr₂RuO₄ exhibits incommensurate antiferromagnetic (AFM) fluctuations, which can evolve into static, short-range AFM order via Ti doping. Moreover, weak ferromagnetic (FM) coupling in Sr₂RuO₄ has also been suggested by NMR/neutron scattering experiments and studies on Ca_2−xSr_xRuO₄ and Sr_2−yLa_yRuO₄, implying orbital dependent magnetism. We report bulk static, short-range FM order in Sr₂RuO₄ triggered by <2% Co doping, showing superconductivity in Sr₂RuO₄ is much closer to FM instability than previously reported in Ca_2−xSr_xRuO₄. We also find Mn doping can effectively establish incommensurate AFM order, with T_N ~ 50 K for 3% Mn doping. These new results place Sr₂RuO₄ in a unique situation where superconductivity lies directly on the borderline of two distinct magnetic states, highlighting the important role of competing magnetic fluctuations in determining superconducting properties of Sr₂RuO₄.

Taccalonolide binding to tubulin imparts microtubule stability and potent in vivo activity

The taccalonolides are highly acetylated steroids that stabilize cellular microtubules and overcome multiple mechanisms of taxane resistance. Recently, two potent taccalonolides, AF and AJ, were identified that bind to tubulin directly and enhance microtubule polymerization. Extensive studies were conducted to characterize these new taccalonolides. AF and AJ caused aberrant mitotic spindles and bundling of interphase microtubules that differed from the effects of either paclitaxel or laulimalide. AJ also distinctly affected microtubule polymerization in that it enhanced the rate and extent of polymerization in the absence of any noticeable effect on microtubule nucleation. In addition, the resulting microtubules were found to be profoundly cold stable. These data, along with studies showing synergistic antiproliferative effects between AJ and either paclitaxel or laulimalide, suggest a distinct binding site. Direct binding studies demonstrated that AJ could not be displaced from microtubules by paclitaxel, laulimalide, or denaturing conditions, suggesting irreversible binding of AJ to microtubules. Mass spectrometry confirmed a covalent interaction of AJ with a peptide of β-tubulin containing the cyclostreptin-binding sites. Importantly, AJ imparts strong inter-protofilament stability in a manner different from other microtubule stabilizers that covalently bind to tubulin, consistent with the distinct effects of the taccalonolides as compared with other stabilizers. AF was found to be a potent and effective antitumor agent that caused tumor regression in the MDA-MB-231 breast cancer xenograft model. The antitumor efficacy of some taccalonolides, which stabilize microtubules in a manner different from other microtubule stabilizers, provides the impetus to explore the therapeutic potential of this site.

Investigation of 20 non-HLA (human leucocyte antigen) psoriasis susceptibility loci in Chinese patients with psoriatic arthritis and psoriasis vulgaris

BACKGROUND

Recently, a number of non-HLA (human leucocyte antigen) psoriasis genetic susceptibility loci have been identified through genome-wide association studies, but data on their association with psoriatic arthritis (PsA) are lacking.

OBJECTIVES

To investigate recently identified psoriasis susceptibility loci in a cohort of Chinese patients with PsA, psoriasis vulgaris (PsV) and healthy controls.

METHODS

Twenty single-nucleotide polymorphisms (SNPs) from 20 loci were selected for genotyping in 379 patients with PsA, 595 patients with PsV and 1181 healthy controls using the MassARRAY platform (Sequenom, San Diego, CA, U.S.A.). Data handling, quality control and association were performed using PLINK software, v. 1.07. The Cochran-Armitage trend test was used to test the genotype-phenotype association.

RESULTS

PsA showed a significant association with markers at TNIP1 (rs17728338, P = 2.20 × 10(-8)), IL28RA (rs4649203, P = 5.04 × 10(-6)), IL12B (rs2082412, P = 3.82 × 10(-5)), ERAP1 (rs27524, P = 1.25 × 10(-3)), PTTG1 (rs2431697, P = 1.22 × 10(-3)) and GJB2 (rs3751385, P = 1.48 × 10(-3)) when compared with the control group. In PsV a significant association was found for IL28RA (rs4649203, P = 9.53 × 10(-7)), TNIP1 (rs17728338, P = 1.21 × 10(-4)) and ERAP1 (rs27524, P = 1.17 × 10(-3)). The allele frequencies were not statistically different between PsA and PsV except for SNPs at IL12B and ZNF816A with a nominal P-value of 0.04 and 0·01, respectively.

CONCLUSIONS

This study provides evidence for the involvement of ERAP1, IL28RA, GJB2 and PTTG1 loci in PsA susceptibility and confirmed the previously reported association with PsA and PsV. These results support the hypothesis that genetic aetiology of psoriasis is the same in both PsA and PsV and also support the higher genetic component of PsA than PsV.

The Effect of Polymer Additives on Surface Quality of Microcellular Injection Molded Parts

Microcellular injection molding is an emerging process for producing foamed plastic parts with complex geometries. It has many advantages including material, energy, and cost savings as well as greater design freedom and dimensional stability. In spite of these advantages, this technique has been limited to non-aesthetic applications by its propensity to create parts with swirling patterns on the surface, a common characteristic of all foamed parts produced. This paper describes a novel method for achieving microcellular injection molded parts free of surface defects. By controlling the amount of supercritical fluid (SCF) and adding the proper type of polymer additives into the polymer, the onset and rate of cell nucleation were properly controlled so that swirl-free microcellular injection molded parts could be successfully molded. This paper presents the theoretical background and experimental results that demonstrate the effect of polymer additives on the surface quality of microcellular injection molded parts.

Study of Microcellular Injection Molding with Expandable Thermoplastic Microsphere

Injection molding with expandable thermoplastic microspheres (ETM) containing blowing chemicals is capable of fabricating lightweight, dimensionally stable plastic parts while using less material. This paper presents the study of microcellular injection molding of low density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS) parts with various ETM contents. It was found that the molded parts exhibit relatively better surface quality than conventional foamed parts. The microcellular morphology and cell density of the fractured cross-sectional surfaces were characterized using a scanning electron microscope (SEM). As reflected by the testing results, the cell microstructure – such as cell size, cell density, and a layered structure with a foamed core sandwiched by skin layers – play an important role in the weight reduction, surface quality, and mechanical properties. A smaller cell diameter and a thicker skin layer help to improve the surface quality and tensile properties of the injection molded parts with ETM. Finally, an appropriate ETM content has a positive effect on cell microstructure and weight reduction, whereas too high a concentration of microspheres adversely affects the tensile properties and surface quality.

XBP1 promoter polymorphism modulates platinum-based chemotherapy gastrointestinal toxicity for advanced non-small cell lung cancer patients

BACKGROUND

The X-box binding protein 1 (XBP1) is a critical transcription factor in the endoplasmic reticulum stress response, which is essential for the maintenance of cellular homeostasis. Here, we investigated whether the regulatory variant rs2269577 of the XBP1 gene influences clinical outcome in advanced non-small cell lung cancer (NSCLC) patients undergoing platinum-based chemotherapy.

PATIENTS AND METHODS

We recruited 663 Chinese patients with advanced NSCLC treated with platinum-based regimens and assessed the association between rs2269577 and clinical outcome. Subsequent functional analyses, including real-time quantitative PCR and dual-luciferase assays, were performed to explore possible molecular mechanisms.

RESULTS

The G/G genotype of rs2269577 was significantly associated with severe gastrointestinal toxicity compared with the homozygous C/C genotype (P=0.012, odds ratio=2.755), particularly in the female, performance status 0-1, and adenocarcinoma subgroups. No significant relevance was found between rs2269577 and treatment efficacy. In gastric epithelial cells, in vitro molecular analyses demonstrated that XBP1 mRNA expression levels decreased after treatment with cisplatin and the G allele of rs2269577 weakened the transcriptional activity of the XBP1 promoter.

CONCLUSION

This is the first study to evaluate the effect of XBP1 polymorphism on severe chemotherapy-related adverse outcomes in platinum-treated advanced NSCLC patients using both pharmacogenomics and functional molecular analyses.