The N-terminal region of Cdc6 specifically recognizes human DNA G-quadruplex

Guanine (G)-rich nucleic acid sequences can form diverse G-quadruplex structures located in functionally significant genome regions, exerting regulatory control over essential biological processes, including DNA replication in vivo. During the initiation of DNA replication, Cdc6 is recruited by the origin recognition complex (ORC) to target specific chromosomal DNA sequences. This study reveals that human Cdc6 interacts with G-quadruplex structure through a distinct region within the N-terminal intrinsically disordered region (IDR), encompassing residues 7-20. The binding region assumes a hook-type conformation, as elucidated by the NMR solution structure in complex with htel21T18. Significantly, mutagenesis and in vivo investigations confirm the highly specific nature of Cdc6's recognition of G-quadruplex. This research enhances our understanding of the fundamental mechanism governing the interaction between G-quadruplex and the N-terminal IDR region of Cdc6, shedding light on the intricate regulation of DNA replication processes.

Role of C9orf72 hexanucleotide repeat expansions in ALS/FTD pathogenesis

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are progressive neurological disorders that share neurodegenerative pathways and features. The most prevalent genetic causes of ALS/FTD is the GGGGCC hexanucleotide repeat expansions in the first intron region of the chromosome 9 open reading frame 72 (C9orf72) gene. In this review, we comprehensively summarize the accumulating evidences elucidating the pathogenic mechanism associated with hexanucleotide repeat expansions in ALS/FTD. These mechanisms encompass the structural polymorphism of DNA and transcribed RNA, the formation of RNA foci via phase separation, and the cytoplasmic accumulation and toxicities of dipeptide-repeat proteins. Additionally, the formation of G-quadruplex structures significantly impairs the expression and normal function of the C9orf72 protein. We also discuss the sequestration of specific RNA binding proteins by GGGGCC RNA, which further contributes to the toxicity of C9orf72 hexanucleotide repeat expansions. The deeper understanding of the pathogenic mechanism of hexanucleotide repeat expansions in ALS/FTD provides multiple potential drug targets for these devastating diseases.

Electronic Janus lattice and kagome-like bands in coloring-triangular MoTe2 monolayers

Polymorphic structures of transition metal dichalcogenides (TMDs) host exotic electronic states, like charge density wave and superconductivity. However, the number of these structures is limited by crystal symmetries, which poses a challenge to achieving tailored lattices and properties both theoretically and experimentally. Here, we report a coloring-triangle (CT) latticed MoTe2 monolayer, termed CT-MoTe2, constructed by controllably introducing uniform and ordered mirror-twin-boundaries into a pristine monolayer via molecular beam epitaxy. Low-temperature scanning tunneling microscopy and spectroscopy (STM/STS) together with theoretical calculations reveal that the monolayer has an electronic Janus lattice, i.e., an energy-dependent atomic-lattice and a Te pseudo-sublattice, and shares the identical geometry with the Mo5Te8 layer. Dirac-like and flat electronic bands inherently existing in the CT lattice are identified by two broad and two prominent peaks in STS spectra, respectively, and verified with density-functional-theory calculations. Two types of intrinsic domain boundaries were observed, one of which maintains the electronic-Janus-lattice feature, implying potential applications as an energy-tunable electron-tunneling barrier in future functional devices.

Inhibition of VEGF binding to neuropilin-2 enhances chemosensitivity and inhibits metastasis in triple-negative breast cancer

Although blocking the binding of vascular endothelial growth factor (VEGF) to neuropilin-2 (NRP2) on tumor cells is a potential strategy to treat aggressive carcinomas, a lack of effective reagents that can be used clinically has hampered this potential therapy. Here, we describe the generation of a fully humanized, high-affinity monoclonal antibody (aNRP2-10) that specifically inhibits the binding of VEGF to NRP2, conferring antitumor activity without causing toxicity. Using triple-negative breast cancer as a model, we demonstrated that aNRP2-10 could be used to isolate cancer stem cells (CSCs) from heterogeneous tumor populations and inhibit CSC function and epithelial-to-mesenchymal transition. aNRP2-10 sensitized cell lines, organoids, and xenografts to chemotherapy and inhibited metastasis by promoting the differentiation of CSCs to a state that is more responsive to chemotherapy and less prone to metastasis. These data provide justification for the initiation of clinical trials designed to improve the response of patients with aggressive tumors to chemotherapy using this monoclonal antibody.

BK channels of five different subunit combinations underlie the de novo KCNMA1 G375R channelopathy

The molecular basis of a severe developmental and neurological disorder associated with a de novo G375R variant of the tetrameric BK channel is unknown. Here, we address this question by recording from single BK channels expressed to mimic a G375R mutation heterozygous with a WT allele. Five different types of functional BK channels were expressed: 3% were consistent with WT, 12% with homotetrameric mutant, and 85% with three different types of hybrid (heterotetrameric) channels assembled from both mutant and WT subunits. All channel types except WT showed a marked gain-of-function in voltage activation and a smaller decrease-of-function in single-channel conductance, with both changes in function becoming more pronounced as the number of mutant subunits per tetrameric channel increased. The net cellular response from the five different types of channels comprising the molecular phenotype was a shift of -120 mV in the voltage required to activate half of the maximal current through BK channels, giving a net gain-of-function. The WT and homotetrameric mutant channels in the molecular phenotype were consistent with genetic codominance as each displayed properties of a channel arising from only one of the two alleles. The three types of hybrid channels in the molecular phenotype were consistent with partial dominance as their properties were intermediate between those of mutant and WT channels. A model in which BK channels randomly assemble from mutant and WT subunits, with each subunit contributing increments of activation and conductance, approximated the molecular phenotype of the heterozygous G375R mutation.

B-Cell-Derived TGF-β1 Inhibits Osteogenesis and Contributes to Bone Loss in Periodontitis

B cells play a vital role in the elimination of periodontal pathogens, the regulation of the immune response, and the induction of tissue destruction. However, the role of B cells in the dysfunction of mesenchymal stem cell (MSC) differentiation to osteoblasts in periodontitis (PD) has been poorly studied. Here we show that the frequency of CD45^-CD105⁺CD73⁺ MSCs in inflamed periodontal tissues is significantly decreased in patients with PD compared with that of healthy controls. CD19⁺ B cells dominate the infiltrated immune cells in periodontal tissues of patients with PD. Besides, B-cell depletion therapy reduces the alveolar bone loss in a ligature-induced murine PD model. B cells from PD mice express a high level of TGF-β1 and inhibit osteoblast differentiation by upregulating p-Smad2/3 expression and downregulating Runx2 expression. The inhibitory effect of PD B cells on osteoblast differentiation is reduced by TGF-β1 neutralization or Smad2/3 inhibitor. Importantly, B-cell-specific knockout of TGF-β1 in PD mice significantly increases the number of CD45^-CD105⁺Sca1⁺ MSCs, ALP-positive osteoblast activity, and alveolar bone volume but decreases TRAP-positive osteoclast activity compared with that from control littermates. Lastly, CD19⁺CD27⁺CD38^- memory B cells dominate the B-cell infiltrates in periodontal tissues from both patients with PD and patients with PD after initial periodontal therapy. Memory B cells in periodontal tissues of patients with PD express a high level of TGF-β1 and inhibit MSC differentiation to osteoblasts. Thus, TGF-β1 produced by B cells may contribute to alveolar bone loss in periodontitis, in part, by suppressing osteoblast activity.

An allosteric modulator activates BK channels by perturbing coupling between Ca2+ binding and pore opening

BK type Ca²⁺-activated K⁺ channels activate in response to both voltage and Ca²⁺. The membrane-spanning voltage sensor domain (VSD) activation and Ca²⁺ binding to the cytosolic tail domain (CTD) open the pore across the membrane, but the mechanisms that couple VSD activation and Ca²⁺ binding to pore opening  are not clear. Here we show that a compound, BC5, identified from in silico screening, interacts with the CTD-VSD interface and specifically modulates the Ca²⁺ dependent activation mechanism. BC5 activates the channel in the absence of Ca²⁺ binding but Ca²⁺ binding inhibits BC5 effects. Thus, BC5 perturbs a pathway that couples Ca²⁺ binding to pore opening to allosterically affect both, which is further supported by atomistic simulations and mutagenesis. The results suggest that the CTD-VSD interaction makes a major contribution to the mechanism of Ca²⁺ dependent activation and is an important site for allosteric agonists to modulate BK channel activation.

AB0171 TOWARDS A BETTER IMPLEMENTATION OF TREAT-TO-TARGET STRATEGY IN RHEUMATOID ARTHRITIS: A COMPARISON OF TWO REAL-WORLD COHORTS

Background

Treat-to-target (T2T) strategy has been the core of rheumatoid arthritis (RA) management for over a decade, however implemented distinctly varied in real practices.

Objectives

We tried to investigate the differences in disease activity and target achievement of two cohorts with different T2T implementations.

Methods

We used data of the CENTRA (Collaboratively intENsive Treat-to-target in RA) and TARRA (Treat-to-TARget in RA) cohorts. The CENTRA is a RA cohort prospectively follow-up by a fixed team with tight control, while the TARRA is a longitudinal observational cohort follow-up by a rheumatologist with casual control. Patients from two cohorts were matched 1:3 by propensity score matching (PSM). The primary outcome was simplified disease activity index (SDAI) at 1-year follow-up.

Results

102 patients from the CENTRA cohort and 271 patients from the TARRA cohort were included. Both groups were comparable in terms of age, gender, disease course, and seropositivity. At the end of 1 year follow-up, the SDAI of patients in the CENTRA cohort was significantly lower than that of patients in the TARRA cohort (2.1 vs 3.4, p＜0.001). The follow-up interval of patients in the CENTRA cohort was significantly shorter than that in the TARRA cohort when patients have not achieved remission (3.1 vs. 3.3 months, p=0.019).

Conclusion

RA patients may benefit more from a tight control T2T strategy with closer follow-up and appropriate education compared with a casual T2T strategy.

Disclosure of Interests

None declared

POS0599 IMPACT OF TREAT-TO-TARGET THERAPY ON BONE MINERAL DENSITY LOSS IN PATIENTS WITH RHEUMATOID ARTHRITIS: A PROSPECTIVE COHORT STUDY

Background

Osteoporosis is a common comorbidity of rheumatoid arthritis (RA). Although RA disease activity has been demonstrated to be associated with bone loss in previous studies, most of them were cross-sectional studies and not in the context of treat-to-target (T2T) strategies.

Objectives

To evaluate the association of disease activity with bone mineral density (BMD) changes in the context of T2T strategies in a prospective RA cohort.

Methods

RA patients were enrolled from a prospective CENTRA cohort of Peking University First Hospital. BMD was repeated at baseline, 1-year and then every other year. Time-adjusted mean disease activity scores were adopted to reflect the overall disease activity during follow-up. The influence of univariable associations between predictors and BMD was investigated using linear regression.

Results

A total of 268 patients were included in our analysis. Their mean age was 50 (12.9) years old. At enrollment, the mean (SD) DAS28-ESR was 3.70 (1.17), and the median (IQR) CDAI and SDIA was 10 (14.45) and 10.30 (16.53), respectively. Osteoporosis at lumbar spine was observed in 23.1% patients and 9.3% at femoral neck at enrollment. Older age, higher SDAI score and lower BMI were found to be associated with osteoporosis at baseline. Reevaluations of BMD at 1 year was applied in 144 patients. Mean decreases of BMDs were 1.75 % at the lumbar spine and 1.40 % at femoral neck at 1 year form baseline, respectively. Patients who achieved remission had less yearly bone loss at lumbar spine (p=0.036). Female gender was identified as a risk factor in the multiple linear regression analyses, and lower disease activity and bisphosphonates were protective factors of continuous bone loss.

Conclusion

Disease activity is associated with bone loss in RA patients in the context of T2T strategies, and those who achieved remission had less yearly bone loss.

Disclosure of Interests

None declared

POS0315 DIAGNOSTIC PERFORMANCE OF CASPAR CRITERIA FOR PSORIATIC ARTHRITIS WITH OR WITHOUT INTEGRATION OF ULTRASOUND

Background

Although the CASPAR criteria in the diagnosis of psoriatic arthritis (PsA) have been validated, CASPAR based on physical examination (PE) is not “gold standard”. The ultrasound (US) could improve the diagnostic accuracy as compared to clinical examination alone.

Objectives

To evaluate the diagnostic performance of CASPAR criteria for psoriatic arthritis (PsA) with or without integration of ultrasound (US).

Methods

The patients with hint of PsA were enrolled. Tender and swollen joint counts, presents of enthesitis and dactylitis were collected by physical examination (PE). US was performed to evaluate peripheral joints, entheses and tendons. The additional value of US to CASPAR criteria were analysed.

Results

326 consecutive patients were enrolled, with 164 PsA and 162 non-PsA. Significantly higher frequencies of tenosynovitis and enthesitis on US and new bone formation on X-ray were found in PsA than non-PsA patients (56.7% vs. 13.0%; 62.2% vs. 14.2%; 62.2% vs. 8.0%, p<0.01 for all). Logistic regression analysis showed that dactylitis (OR=12.0, p<0.01), family history of PsO/PsA (OR=3.1, p<0.05), nail involvement (OR=3.5, p=0.01), new bone formation (OR=14.8, p<0.01) and tenosynovitis on US (OR=21.3, p<0.01), enthesitis on US (OR=21.7, p<0.01) were independent risk factors for PsA. Adding US tenosynovitis and/or enthesitis to CASPAR criteria showed better performance by improving the specificity (91.4% vs. 67.9%) and meanwhile keeping sensitivity (92.1% vs. 96.3%). When replacing hand X-ray by US in CASPAR criteria, the sensitivity and specificity were comparable to CASPAR criteria adding with US. The diagnostic accuracy was 82.2% for CASPAR criteria based on PE, 91.7% for CASPAR integrated with US, and 91.4% for CASPAR with US to replace X-ray.

Conclusion

CASPAR criteria based on US improve the diagnosis utility of PsA than CASPAR criteria based on PE. US assessment is valuable in the diagnosis of PsA.

References

[1]Fiorenza A, Bonitta G, Gerratana E, et al. Assessment of enthesis in patients with psoriatic arthritis and fibromyalgia using clinical examination and ultrasound. Clinical and experimental rheumatology 2020;38 Suppl 123:31-9.

[2]Zabotti A, Bandinelli F, Batticciotto A, et al. Musculoskeletal ultrasonography for psoriatic arthritis and psoriasis patients: a systematic literature review. Rheumatology (Oxford) 2017;56:1518-32.

Figure 1.

ROC curves for adding US or substituting X-ray by US in CASPAR criteria. Receiver operating characteristic (ROC) curve illustrates the diagnosis performance of CASPAR criteria adding US or substituting X-ray by US in CASPAR criteria and CASPAR criteria based on PE alone. The area under the curve of the ROC curve (AUC) was 0.929 (95%CI 0.897, 0.961) (p<0.01) for adding US to CASPAR criteria. AUC was 0.908 (95%CI 0.876, 0.940) (p<0.01) for CASPAR criteria based on PE. And AUC was 0.916 (95%CI 0.880, 0.951) (p<0.01) for substituting X-ray by US in CASPAR criteria. CASPAR: ClASsification criteria for Psoriatic ARthritis; PE: physical examination; US: ultrasound.

Disclosure of Interests

None declared

Hydrogen Spillover-Enhanced Heterogeneously Catalyzed Hydrodeoxygenation for Biomass Upgrading

Hydrodeoxygenation (HDO) is regarded as a promising technology for biomass upgrading to obtain sustainable and competitive chemicals and fuels. In fact, biomass HDO over heterogeneous solid catalysts is often accompanied by the phenomenon of hydrogen spillover, which further affects the catalytic performance. Thus, it is necessary to gain in-depth understand the promoting effect of hydrogen spillover in the biomass HDO process to obtain desired conversion and selectivity. This Review summarized the extensive research on hydrogen spillover in biomass refining and discussed in detail the regulation mechanism of hydrogen spillover in biomass HDO process, mainly by regulating different active center sites on catalyst supports, such as metal sites, acid sites, surface functional groups, and defective sites, which exhibit independent and synergistic characteristics promoting catalyst activity, selectivity, and stability. Finally, the prospective of hydrogen spillover in biomass HDO applications was critically evaluated, and the key technical challenges in developing "hydrogen-free" HDO and upgrading biofuels were highlighted. The presentation of hydrogen spillover-enhanced catalytic biomass HDO in this Review will hopefully provide insight and guidance for further development of efficient catalysts and preparation of high-value chemicals in the future.

Iodine-125 brachytherapy for the treatment of central mucoepidermoid carcinoma of the jaw in a pre-teen

Central mucoepidermoid carcinoma (MEC) of the jaw is a rare malignant neoplasm, even rarer in teenagers. Radical surgical resection, such as en bloc resection or segmental resection, is the main treatment for MEC of the jaw. This surgical treatment results in a loss of integrity of the jaw. The successful application of iodine-125 brachytherapy for the treatment of intraosseous MEC of the mandible in an 11-year-old girl is reported here. No local recurrence or distant metastasis was observed during 6 years of follow-up. The integrity of the mandible was preserved and the development of the mandible was not significantly affected. Iodine-125 brachytherapy is a potential alternative treatment for central mucoepidermoid carcinoma of the jaw, especially in teenagers, and may preserve the continuity and function of the jaw.

[Analysis of molecular and clinical characteristics of carbapenem-resistant hypervirulent Klebsiella pneumoniae in the intensive care unit]

To investigate the carbapenemases distribution of carbapenem-resistant Klebsiella pneumoniae (CRKP) in the intensive care unit, and the clinical characteristics between carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) and carbapenem-resistant non-hypervirulent Klebsiella pneumoniae (CR-non-hvKP) were compared. A total of 53 non-repetitive CRKP strains isolated from 49 patients in the intensive care unit of the Second Affiliated Hospital of Xi'an Jiaotong University from May 2020 to March 2021 were retrospectively studied. The carbapenemase inhibitor enhancement test was used for screening carbapenemase-producing strains, and the string test was carried out to screen the hypermucoviscosity phenotype. Using PCR to detect five main carbapenemase genes (bla_KPC-2, bla_NDM, bla_IMP , bla_VIM and bla_OXA-48-like), common serotype (K1 and K2) and virulence gene (rmpA and iutA). Treated the strains with both rmpA and iutA genes as hypervirulent Klebsiella pneumonia (hvKP), and the whole genome sequencing of CR-hvKP was completed. At the same time, the clinical data of 49 patients were sorted out, and the differences in clinical characteristics of CR-hvKP and CR-non-hvKP infected patients were compared using the independent sample t test, Mann-Whitney U test, chi-square test or Fisher's exact probability test. CRKP isolated from the intensive care unit were extensively drug resistance and still had a good sensitivity to polymyxin B and tigecycline. Producing carbapenemases were the main resistance mechanism of CRKP (52/53, 98.1%). Of the 53 CRKP strains, except for 1strain that did not detect carbapenemase, at least one carbapenemase resistance gene was detected in the remaining 52 CRKP strains, of which 45 strains carried an enzyme, including 36 bla_KPC-2 (36/53, 67.9%), 8 bla_NDM (8/53, 15.1%), 1 bla_IMP (1/53, 1.9%), and 7 strains carried with both bla_KPC-2 and bla_NDM (7/53, 13.2%). String test and virulence gene showed that 7 CR-hvKP strains (13.2%) were detected in 53 CRKP strains, and two of which were hypermucoviscosity phenotype. Sequencing results revealed that CR-hvKP were mainly ST11 type. Almost all patients with CR-hvKP infection were over 60 years old (7/7), with invasive treatment (7/7), pulmonary infection with hypermucoviscosity phenotype (2/7) and high mortality (5/7); and the percentage of neutrophils in patients with CR-hvKP infection (86.44±4.70) % was higher than those patients with CR-non-hvKP infection (78.90±19.15) %, the difference was statistically significant (t=-2.225, P=0.032). The CR-hvKP strains in the intensive care unit mainly produced KPC-2 enzyme, with K2 capsular serotype and ST11 type. It is necessary to strengthen the monitoring and control of the CR-hvKP strain to prevent the co-evolution of drug-resistant and hypervirulent strains.

[The standardized diagnosis and treatment of rheumatoid arthritis]

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation of the joints with high risk of disability. In recent years, remarkable progress has been made towards the diagnosis and treatment of RA, and the international RA guidelines have been also kept updated. Nevertheless, there are many challenges in China, especially inadequate number of rheumatologists and insufficient experience in the diagnosis and treatment of RA. Therefore, Chinese Rheumatology Association drafted the standardized diagnosis and treatment of RA based on the available evidence, so as to improve the management of RA patients in China.

Crystal structure of parallel G-quadruplex formed by the two-repeat ALS- and FTD-related GGGGCC sequence

The hexanucleotide repeat expansion, GGGGCC (G4C2), within the first intron of the C9orf72 gene is known to be the most common genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The G4C2 repeat expansions, either DNA or RNA, are able to form G-quadruplexes which induce toxicity leading to ALS/FTD. Herein, we report a novel crystal structure of d(G4C2)2 that self-associates to form an eight-layer parallel tetrameric G-quadruplex. Two d(G4C2)2 associate together as a parallel dimeric G-quadruplex which folds into a tetramer via 5'-to-5' arrangements. Each dimer consists of four G-tetrads connected by two CC propeller loops. Especially, the 3'-end cytosines protrude out and form C·C+•C·C+/ C·C•C·C+ quadruple base pair or C•C·C+ triple base pair stacking on the dimeric block. Our work sheds light on the G-quadruplexes adopted by d(G4C2) and yields the invaluable structural details for the development of small molecules to tackle neurodegenerative diseases, ALS and FTD.

AB0280 THE INFLUENCE OF TARGET THERAPY AS WELL AS GLUCOCORTICOIDS TAPERING ON DISEASE FLARE IN SYSTEMIC LUPUS ERYTHEMATOSUS: RESULTS FROM A PROSPECTIVE CHINESE COHORT

Background:

Treat-to-target in systemic lupus erythematosus (SLE) has been proposed for 7 years and several recommendations were developed [1]. In these recommendations, prevention of flares should be a realistic target. Meanwhile, ‘remission’ or ‘low disease activity’ was recommended as the treatment target and minimizing glucocorticoids (GC) dose or withdrawal if possible was suggested in the maintenance treatment. However, would target therapy and GC tapering/withdrawal influence disease flare?

Objectives:

To investigate the frequency and determinants of disease flare, especially the influence of target therapy as well as GC tapering on flare in Chinese lupus patients.

Methods:

The baseline and follow-up data of all consecutive patients in a prospective longitudinal lupus cohort from January 2017 to June 2020 were collected. The lupus low disease activity state (LLDAS) was defined as in Golder et al., 2019[2]. The criteria for remission were from DORIS definitions [3]. Flare was assessed using the SELENA-SLEDAI flare index [4].

Results:

We enrolled 185 patients with disease duration at recruitment of 2.3 (0.8–7.7) years. During the 26.2 (12.5-34.5) months of follow-up, 73 (39.5%) patients experienced 95 flares, including 70 mild/moderate and 25 severe flares. The incidence of flare per patient-year was 0.27. Kaplan-Meier analyses showed that compared with those who never achieved LLDAS or DORIS, the patients who achieved the target at least once had a higher flare free survival rate; meanwhile, the patients with prednisone withdrawn had significantly lower flare free rate compared with those with small dose of GC maintained (≤7.5mg/d) (Figure 1A), but among the patients with different prednisone maintain doses (7.5~5mg, 5~2.5mg, and ≤2.5mg) there was not significant difference (Figure 1B). Cox regression analysis showed that younger age at disease onset and lower Complement 3 (C3) level at recruitment were independent risk factors for flare and achieving LLDAS or DORIS ≥50% of visits was independent protective factor (Table 1).

Conclusion:

In this Chinese prospective SLE cohort, age at disease onset, C3 level at recruitment and therapeutic target achieving influenced disease flare independently and significantly. GC tapering in appropriate patients and with appropriate pace did not increase the flare rate, but prednisone withdrawal may induce more disease exacerbation, which needs to be confirmed by large prospective studies.

References:

[1]Van Vollenhoven R F, et al. Treat-to-target in systemic lupus erythematosus: recommendations from an international task force. Ann Rheum Dis, 2014. 73(6): 958-967

[2]Golder, V., et al. Lupus low disease activity state as a treatment endpoint for systemic lupus erythematosus: a prospective validation study. The Lancet Rheumatology, 2019. 1(2): p. e95-e102.

[3]van Vollenhoven R, et al. A framework for remission in SLE: consensus findings from a large international task force on definitions of remission in SLE (DORIS). Ann Rheum Dis. 2017. 76(3): 554–561.

[4]Petri M, et al. Classification and definition of major flares in SLE clinical trials. Lupus. 1999. 8(8): 685-691.

Table 1.

Determinants of disease flare by multivariate Cox regression analyses

Model 1(LLDAS) ΔModel 2(RONT) ΔModel 3(Complete RONT) ΔHR95%CIP valueHR95%CIP valueHR95%CIP valueAge at disease onset (years)†0.970.95-0.990.0040.970.95-0.990.0030.970.95-0.990.003Anti-dsDNA positive at recruitment1.340.82-2.180.2171.120.68-1.850.6491.190.73-1.960.486C3 (mg/L) at recruitment0.9980.997-0.9990.0040.9980.997-0.9990.0070.9980.997-1.0000.010Minimum prednisone dose during follow- up (mg/d)0.980.90-1.080.7161.010.94-1.080.7471.040.97-1.110.243Therapeutic target achieved≥50% of observationsΔ0.600.39-0.940.0010.540.34-0.870.0110.680.51-0.920.011

Δ In the three hazard models, the different target achievement status were included respectively.

RONT: Clinical remission on treatment; Complete RONT: Complete remission on treatment.

Disclosure of Interests:

None declared

[Association between parental education level and left ventricular hypertrophy in childhood]

Objective: To examine the relationship between parental education level and left ventricular hypertrophy (LVH) in children. Methods: The data comes from the baseline survey of the Huantai Childhood Cardiovascular Health Cohort Study (HCCH) conducted in Huantai County, Zibo City, Shandong Province. A convenient cluster sampling method was used to select a primary school in Huantai County, Zibo City, Shandong Province as a survey point. A cross-sectional survey was conducted from November 2017 to January 2018. A total of 1 316 children aged 6-11 years with complete data were included. LVH was defined as left ventricular mass index ≥ sex-and age-specific 90th percentile values of this population. Education levels of both parents were divided into junior high school or lower, high school, university or higher, respectively. Logistic regression models were used to analyze the association between parental education level and LVH in children. Results: The age of 1 316 participants was (8.9±1.5) years old. Among them, there were 703 boys (53.4%).After adjusting for gender, age, intake of vegetables and fruits, intake of carbonated drinks, physical activity, sleep time, screen time, overweight or obesity, and occasional hypertension, the logistic regression model results show that compared with those children whose parents' education level is junior high school or below, paternal or maternal education level of college or higher was associated with odds of LVH (father: OR=0.53, 95%CI: 0.33-0.87; mother: OR=0.52, 95%CI: 0.32-0.87; father/mother: OR=0.54,95%CI: 0.32-0.91). Conclusion: Parental education level is inversely associated with LVH in childhood. The probability of LVH in childhood decreases with the increase of parental education levels.

[The mechanism of hyperbaric oxygen regulating HMGB1 in the prevention and treatment of encephalopathy after acute CO poisoning]

Objective: To study the expression of high mobility group protein 1 (HMGB1) in the brain of rats after hyperbaric oxygen (HBO) treatment of acute carbon monoxide poisoning (DEACMP) , and to explore the mechanism of HBO in the prevention and treatment of DEACMP pathological process by regulating HMGB1. Methods: 108 SD rats were randomly divided into control group (NC group) and co group (CO group) . HBO treatment group (HBO group) , 48 rats in each group. Co group and HBO group were used to establish CO poisoning model, HBO group were treated with hyperbaric oxygen once a day. Water maze test was used to detect and analyze the memory retention ability of three groups of rats in 3 d, 7 d, 14 d. ELISA was used to detect the plasma concentration of HMGB1、IL-6、TNF-α in three groups of rats on the 1 d, 3 d, 7 d, 14 d, 21 d Concentration. Western blotting was used to detect the expression of HMGB1 and Caspase-3 in the brain of the three groups on the 1 d, 3 d, 7 d, 14 d, 21 d. TUNEL staining was used to detect the apoptosis of hippocampal neurons in the three groups. Results: Compared with NC group, the average escape latency of rats in CO group and HBO group was significantly prolonged, and the activity time of platform quadrant in CO group was significantly shortened on 14 d and 21 d (P<0.05) ; compared with CO group, the average escape latency of HBO group on 7 d, 14 d and 21 d was significantly shortened (P<0.05) . Compared with NC group, plasma HMGB1 in CO group and HBO group were significantly increased (P<0.05) ; after 3 days, HBO group was significantly lower than co group, the difference was statistically significant (P<0.05) . The levels of IL-6 and TNF-α in HBO group and co group increased rapidly and then decreased gradually. The increased levels of IL-6 and TNF-α in HBO group were significantly lower than those in CO group (P<0.05) . Compared with NC group, the expression of HMGB1 and Caspase-3 in CO group was significantly increased on 3 d, 7 d and 14 d (P<0.05) ; the expression of HMGB1 and Caspase-3 in HBO group was significantly increased on 3 d, 7 d, 14 d and 21 d (P<0.05) ; compared with CO group, the expression of HMGB1 and Caspase-3 in HBO group decreased significantly on 3 d, 7 d, 14 d and 21 d (P<0.05) . The apoptotic index of nerve cells in CO group began to increase at 3 days, which was significantly different from that of NC group (P<0.05) , and the difference was still statistically significant on 21 d (P<0.05) ; the apoptotic index of nerve cells in HBO group was slightly increased, but there was no significant difference compared with NC group (P>0.05) , and the apoptotic index of 3 d, 7 d, 14 d and 21 d in HBO group was significantly lower than that in CO group (P<0.05) . Conclusion: acute CO poisoning can induce the release of HMGB1 and a variety of inflammatory factors. HMGB1 can promote the apoptosis of nerve cells after acute CO poisoning by up regulating the expression of caspase-3 protein, and participate in the pathological process of DEACMP. HBO can down regulate the expression of HMGB1, IL-6, TNF-α and caspase-3 protein, inhibit the apoptosis of nerve cells, and play a protective role on nerve cells.

Structural basis of DNA replication origin recognition by human Orc6 protein binding with DNA

The six-subunit origin recognition complex (ORC), a DNA replication initiator, defines the localization of the origins of replication in eukaryotes. The Orc6 subunit is the smallest and the least conserved among ORC subunits. It is required for DNA replication and essential for viability in all species. Orc6 in metazoans carries a structural homology with transcription factor TFIIB and can bind DNA on its own. Here, we report a solution structure of the full-length human Orc6 (HsOrc6) alone and in a complex with DNA. We further showed that human Orc6 is composed of three independent domains: N-terminal, middle and C-terminal (HsOrc6-N, HsOrc6-M and HsOrc6-C). We also identified a distinct DNA-binding domain of human Orc6, named as HsOrc6-DBD. The detailed analysis of the structure revealed novel amino acid clusters important for the interaction with DNA. Alterations of these amino acids abolish DNA-binding ability of Orc6 and result in reduced levels of DNA replication. We propose that Orc6 is a DNA-binding subunit of human/metazoan ORC and may play roles in targeting, positioning and assembling the functional ORC at the origins.

Novel SLC26A6 gene polymorphism rs184187143 is associated with diabetic ketoacidosis of gestational diabetes

OBJECTIVE

Diabetic ketoacidosis is one of the most serious acute complications of the gestational diabetes and is marked by the triad of the uncontrolled hyperglycemia, acidosis, and ketosis. Diabetic ketoacidosis can be a life-threatening emergency for mother and fetus, whose genetic factors resulting in diabetic ketoacidosis remain unclear. This study aimed to explore the correlation between SLC26A6 gene polymorphism rs184187143 and the risk of diabetic ketoacidosis of gestational diabetic mellitus (GDM).

PATIENTS AND METHODS

A total of 98 patients with GDM and 98 patients with diabetic ketoacidosis of GDM were enrolled. The direct sequencing of the products by Polymerase Chain Reactions of the extracted genomic DNA from the involved patients was performed to analyze the SLC26A6 gene polymorphism rs184187143, and the further genotype frequencies were compared to the statistical analysis of the clinical and biochemical data.

RESULTS

A significantly increased prevalence of the G allele (p = 0.032, OR = 2.326, 95% CI = 1.539-3.516), C/G genotype (p = 0.021, OR = 3.582, 95% CI = 1.216-10.558), and a previously uncharacterized rs184187143, was discovered in the diabetic ketoacidosis of the GDM group. The genotype of SLC26A6 rs184187143 was shown to be markedly associated with increased prevalence of the diabetic ketoacidosis of GDM.

CONCLUSIONS

Our study firstly established that the G allele and C/G genotype of rs184187143 single nucleotide polymorphism (SNP) in SLC26A6 gene was closely linked with the increased risk for the development of the diabetic ketoacidosis of GDM.

AB0243 THE SHORT DISEASE DURATION IS ASSOCIATED WITH WORSE MOOD DISORDER IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) is commonly associated with mood disorders, especially depression and anxiety. But the status of mood disorders in RA patients with different courses is unknown.

Objectives:

The aims of this study were to investigate the frequencies of depression and anxiety in patients with early RA and non-early RA, and further to identify the risk factors for mood disorders.

Methods:

Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) were applied to all enrolled RA patients to assess their corresponding status of anxiety and depression. Besides clinical assessment, power Doppler and grey-scale ultrasound of 22 joints were also performed. The status of mood disorder was studied in early RA patients compared to non-early RA patients. Multivariate regression was used to identify the risk factor for mood disorders.

Results:

201 RA patients were enrolled, with 76 early RA (disease duration≤2 years) and 125 non-early RA (disease duration > 2 years) patients. Mood disorder (depression and/or anxiety) was found in 20.9% (42/201) patients. Depression was more often observed in early RA patients than non-early RA patients (26.3% vs. 14.4%,P=0.036). The similar trend for anxiety was observed also in early RA patients compared to non-early RA patients, although the difference was insignificant (13.2% vs. 5.6%,P=0.062). Multivariate logistic regression analysis showed that disease duration (OR 0.991 [95% CI 0.985-0.998]), rheumatoid factor concentration (OR 2.697 [95% CI 1.165-6.241]), Health Assessment Questionnaire Disability Index (HAQ-DI) (OR 1.045 [95% CI 1.001-1.091]) and grey-scale synovitis score (GS score) (OR 1.092 [95% CI 1.032-1.156]) were independent risk factors for predicting depression in RA. Disease duration (OR 0.983 [95% CI 0.970-0.997]), HAQ-DI (OR 1.069 [95% CI 1.002-1.141]) and GS score (OR 1.073 [95% CI 1.005-1.141]) were independent risk factors for predicting anxiety in RA patients.

Conclusion:

Mood disorders were almost doubled in frequency in early RA patients than non-early RA patients. RA Patients with short disease duration, high HAQ-DI and high GS score were more likely to be in depression and anxiety. More attention is needed to the psychological status of RA patients, especially those at an early stage, with poor physical function and severe synovitis.

References:

[1]Sturgeon JA, Finan PH, Zautra AJ. Affective disturbance in rheumatoid arthritis: psychological and disease-related pathways. Nat Rev Rheumatol 2016;12(9):532-42.

[2]Bacconnier L, Rincheval N, Flipo RM, et al. Psychological distress over time in early rheumatoid arthritis: results from a longitudinal study in an early arthritis cohort. Rheumatology (Oxford) 2015; 54(3): 520-7.

Acknowledgments:

The authors thank all the colleagues in our department.

Disclosure of Interests:

None declared

SAT0562 ADDITIONAL BENEFIT OF ULTRASOUND TO THE EARLY DIAGNOSIS OF PSORIATIC ARTHRITIS

Background:

Being an inflammatory disease of joint, spine or enthesis is the premise of the CASPAR diagnostic criteria for psoriatic arthritis (PsA). Traditionally, the assessment of local inflammation in joint, enthesis and tendon relies on physical examinations. But multiple studies have demonstrated that ultrasound (US) is capable of detecting subclinical inflammation as well as non-inflammatory lesions.

Objectives:

To compare the capabilities of physical examination and US findings in the diagnosis of early PsA, and further identify the US features which are most valuable for the diagnosis of PsA.

Methods:

66 patients with suspected PsA or early PsA (disease duration< 2 years) due to psoriasis with joint pain or seronegative inflammatory arthritis were enrolled and further assessed by both physical examination and ultrasound (US).Tender and swollen joint counts based on 68/66 joints, tender tendons, enthesitis (14 entheses) and dactylitis (20 digits) count were collected by physical examination. Abnormalities of peripheral joints, entheses and tendons were also evaluated by US. New bone formation was evaluated by hand X-ray. The diagnostic capacity of CASPAR criteria based on US and based on physical examination were compared. The diagnosis value of US features as well as clinical characteristics were analyzed. The clinical diagnosis of PsA by the expert panel was taken as the standard.

Results:

CASPAR criteria based on US showed a higher specificity than those based on physical examination (96.7% vs. 53.3%) with a bit decrease of sensitivity (91.7% vs. 97.2%). 36 patients were eventually diagnosed as PsA and 30 patients were non-PsA. Gender distribution, mean age and disease duration were equally distributed in two groups of patients. Dermatology Life Quality Index (DLQI) was higher in PsA patients than non-PsA patients. Significantly more patients had nail change and new bone formation on hand X-ray in PsA patients than in non-PsA patients (69.4% vs. 26.7%,P=0.001 and 66.7% vs. 13.3%,P<0.001 respectively). Significantly higher frequencies of synovitis/synovium hypertrophy, tenosynovitis and enthesitis were found in PsA patients than non-PsA patients (58.3% vs 20.0%,P=0.002, 38.9% vs 3.3%,P=0.001 and 52.8% vs 13.3%,P=0.002, respectively). Logistic regression analysis showed that nail change (OR=25.1, P=0.007), new bone formation on X-ray (OR=33.1, P=0.003), tenosynovitis on US (OR=149.1, P=0.003) and enthesitis on US (OR=39.2, P=0.008) were independent risk factors for predicting the diagnosis of PsA.

Conclusion:

US increased the specificity of CASPAR criteria compared with physical examination. Combined nail change, new bone formation on X-ray, tenosynovitis and enthesitis on US improved the diagnosis of early PsA.

References:

[1]Polachek A, Cook R, Chandran V, et al. The association between sonographic enthesitis and radiographic damage in psoriatic arthritis. Arthritis Res Ther 2017; 19(1): 189.

[2]Faustini F, Simon D, Oliveira I, et al. Subclinical joint inflammation in patients with psoriasis without concomitant psoriatic arthritis: a cross-sectional and longitudinal analysis. Ann Rheum Dis 2016; 75(12): 2068-74.

Acknowledgments:

The author thank all the colleagues in the department of Rheumatology of Guy’s hospital.

Disclosure of Interests:

None declared

The crystal structure of an antiparallel chair-type G-quadruplex formed by Bromo-substituted human telomeric DNA

Human telomeric guanine-rich DNA, which could adopt different G-quadruplex structures, plays important roles in protecting the cell from recombination and degradation. Although many of these structures were determined, the chair-type G-quadruplex structure remains elusive. Here, we present a crystal structure of the G-quadruplex composed of the human telomeric sequence d[GGGTTAGG8GTTAGGGTTAGG20G] with two dG to 8Br-dG substitutions at positions 8 and 20 with syn conformation in the K+ solution. It forms a novel three-layer chair-type G-quadruplex with two linking trinucleotide loops. Particularly, T5 and T17 are coplanar with two water molecules stacking on the G-tetrad layer in a sandwich-like mode through a coordinating K+ ion and an A6•A18 base pair. While a twisted Hoogsteen A12•T10 base pair caps on the top of G-tetrad core. The three linking TTA loops are edgewise and each DNA strand has two antiparallel adjacent strands. Our findings contribute to a deeper understanding and highlight the unique roles of loop and water molecule in the folding of the G-quadruplex.

Afatinib versus methotrexate as second-line treatment in Asian patients with recurrent or metastatic squamous cell carcinoma of the head and neck progressing on or after platinum-based therapy (LUX-Head & Neck 3): an open-label, randomised phase III trial

BACKGROUND

Treatment options are limited for patients with recurrent or metastatic squamous cell carcinoma of the head and neck (HNSCC) following progression after first-line platinum-based therapy, particularly in Asian countries.

PATIENTS AND METHODS

In this randomised, open-label, phase III trial, we enrolled Asian patients aged ≥18 years, with histologically or cytologically confirmed recurrent/metastatic HNSCC following first-line platinum-based therapy who were not amenable for salvage surgery or radiotherapy, and had an Eastern Cooperative Oncology Group (ECOG) performance status of 0/1. Patients were randomised (2 : 1) to receive oral afatinib (40 mg/day) or intravenous methotrexate (40 mg/m2/week), stratified by ECOG performance status and prior EGFR-targeted antibody therapy. The primary end point was progression-free survival (PFS) assessed by an independent central review committee blinded to treatment allocation.

RESULTS

A total of 340 patients were randomised (228 afatinib; 112 methotrexate). After a median follow-up of 6.4 months, afatinib significantly decreased the risk of progression/death by 37% versus methotrexate (hazard ratio 0.63; 95% confidence interval 0.48-0.82; P = 0.0005; median 2.9 versus 2.6 months; landmark analysis at 12 and 24 weeks, 58% versus 41%, 21% versus 9%). Improved PFS was complemented by quality of life benefits. Objective response rate was 28% with afatinib and 13% with methotrexate. There was no significant difference in overall survival. The most common grade ≥3 drug-related adverse events were rash/acne (4% with afatinib versus 0% with methotrexate), diarrhoea (4% versus 0%), fatigue (1% versus 5%), anaemia (<1% versus 5%) and leukopenia (0% versus 5%).

CONCLUSIONS

Consistent with the phase III LUX-Head & Neck 1 trial, afatinib significantly improved PFS versus methotrexate, with a manageable safety profile. These results demonstrate the efficacy and feasibility of afatinib as a second-line treatment option for certain patients with recurrent or metastatic HNSCC.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01856478.

Meta-analysis of the association between primary tumour location and prognosis after surgical resection of colorectal liver metastases

BACKGROUND

Primary tumour location is emerging as an important prognostic factor in localized and metastatic colorectal cancers. However, its prognostic role in colorectal liver metastasis (CRLM) after hepatectomy remains controversial. A systematic review and meta-analysis was undertaken to evaluate its prognostic value.

METHODS

References were identified through searches of PubMed, Embase, Web of Science and the Cochrane Library comparing overall or disease-free survival after hepatic resection between patients with CRLM originating from right- or left-sided colorectal cancers. Data were pooled using hazard ratios (HRs) and 95 per cent confidence intervals according to a random-effects model. Meta-regression and subgroup analyses were conducted to assess the effect of underlying confounding factors on HR estimates and to adjust for this.

RESULTS

The final analysis included 21 953 patients from 45 study cohorts. Compared with left-sided primary tumour location, right-sided location was associated with worse overall survival (HR 1·39, 95 per cent c.i. 1·28 to 1·51; P < 0·001; prediction interval 1·00 to 1·93), and also tended to have a negative impact on disease-free survival (HR 1·18, 1·06 to 1·32; P = 0·004; prediction interval 0·79 to 1·75). Subgroup analysis showed that the negative effect of right-sided primary tumour location on overall survival was more prominent in the non-Asian population (HR 1·47, 1·33 to 1·62) than the Asian population (HR 1·18, 1·05 to 1·32) (P for interaction <0·01).

CONCLUSION

This study demonstrated a prognostic role for primary tumour location in patients with CRLM receiving hepatectomy, especially regarding overall survival. Adding primary tumour location may provide important optimization of prognosis prediction models for CRLM in current use.

Rapid improvement of muscle weakness post-thymectomy indicates good long-term neurological outcome in patients with ocular myasthenia gravis

BACKGROUND AND PURPOSE

This study was conducted to evaluate whether post-thymectomy rapid remission of ocular myasthenia gravis (oMG) is a prognostic indicator of good long-term neurological outcome.

METHODS

Eighty-four oMG patients who underwent thymectomy at our institute were enrolled. The incidence of 5-year complete stable remission (CSR) was compared between patients with rapid remission of MG status (<1 month after surgery) and those with non-rapid remission.

RESULTS

Kaplan-Meier survival analysis indicated that the incidence of CSR was higher in oMG patients with rapid remission than in those without rapid remission (P < 0.001). Multivariate analysis showed that rapid remission (odds ratio 16.34, 95% confidence interval 3.58-74.60, P < 0.001) is an independent prognostic factor for CSR.

CONCLUSION

Postoperative rapid remission of MG status predicts a higher likelihood of complete remission in patients with oMG.

Evaluation and comparison of the diagnostic performance of routine blood tests in predicting liver fibrosis in chronic hepatitis B infection

Background & aims: Biopsy is the gold standard for staging liver fibrosis, but it may be accompanied by complications. As an alternative, non-invasive markers such as transient elastography (for liver fibrosis) and certain combinations of routine blood markers (liver function tests, full blood count) have been developed although their clinical significance remains controversial. Here, we compare the diagnostic values of non-invasive markers for liver fibrosis in patients with chronic hepatitis B infection. Methods: Transient elastography and routine laboratory tests were performed in 196 patients. Diagnostic performances were compared and were assessed based on the area under the curve (AUC) of a receiver operating characteristic (ROC) analysis. Results: Elevated GGT to platelet ratio (GPR), the fibrosis index FIB-4 [based on age, AST, platelets and ALT], platelet to lymphocyte ratio (PLR) and total bilirubin were independent predictors of liver stiffness defined by transient elastography (all P < 0.001). The AUCs of GPR in predicting both advanced fibrosis and cirrhosis were significantly larger than that of FIB-4 (P = 0.037 and P = 0.008, respectively) and AST-to-platelet ratio index (APRI) (P = 0.008 and P = 0.005). FIB-4, APRI and red cell volume distribution width-to-platelet ratio (RPR) had similar diagnostic values in discriminating different levels of liver fibrosis. Conclusions: GPR showed the best diagnostic value and RPR and PLR are easily available and inexpensive markers in evaluating fibrosis and cirrhosis. The diagnostic values of these laboratory markers are useful in diagnosing advanced fibrosis or cirrhosis, and in confirming the different levels of liver fibrosis.

Dexmedetomidine attenuation of renal ischaemia-reperfusion injury requires sirtuin 3 activation

BACKGROUND

Dexmedetomidine attenuates renal ischaemia and reperfusion (I/R) injury, but its mechanism of action is unclear. As sirtuin 3 (SIRT3) activation can alleviate acute kidney injury, we investigated whether dexmedetomidine acts through SIRT3 to reduce renal I/R injury.

METHODS

The potential involvement of SIRT3 in dexmedetomidine attenuation of renal I/R injury was tested in HK2 cells subjected to hypoxia/reoxygenation and C57BL/6J mice subjected to renal I/R. A short interfering RNA targeting SIRT3 was used in some experiments to examine the potential role of SIRT3. Cell death and mitochondrial membrane potential (Δψm) were analysed in cultured cells. Mitochondrial damage in mice was assessed using electron microscopy and markers for renal function. Expression of cyclophilin D, cytochrome c, and SIRT3, and the level of cyclophilin D acetylation were determined.

RESULTS

Hypoxia/reoxygenation of HK2 cells increased cell death, cytochrome C expression, and cyclophilin D acetylation, and decreased Δψm and SIRT3 expression (P<0.05). Dexmedetomidine attenuated these changes. The dexmedetomidine effects were enhanced by SIRT3 overexpression and eliminated by SIRT3 knockdown. I/R in mice damaged renal function, and increased histological lesions, mitochondrial damage, cytochrome c expression, and cyclophilin D acetylation, while SIRT3 activity was decreased by 51% (P<0.05). Dexmedetomidine inhibited these changes in mice expressing normal levels of SIRT3, but not in SIRT3-knockdown mice.

CONCLUSIONS

Dexmedetomidine appears to act, at least in part, by up-regulating SIRT3 to inhibit mitochondrial damage and cell apoptosis and thereby protect against renal I/R injury.

Wavelength multiplexing of four-wave mixing based fiber temperature sensor with oil-filled photonic crystal fiber

A fiber temperature sensor based on four-wave mixing (FWM) with an oil-filled photonic crystal fiber (PCF) is proposed in this study, and a multipoint measurement based on the wavelength multiplexing of such sensors is constructed for the first time. The sensing performance and signal spectral characteristics of the temperature sensor are theoretically and experimentally studied. The maximum temperature sensitivity of the signal light of 0.207 nm/°C is achieved using a FWM sensing fiber with a length of 10 cm. The signal wavelength response to excitation power is also explored in this experiment. Results showed that the temperature sensor is relatively insensitive to the fluctuation of power change. The wavelength multiplexing of a FWM-based PCF temperature sensor also presents the possibility of multiplexing measurement and multipoint sensing, and high multiplexed capability is theoretically predicted to be obtainable with optimized sensitivity and splicing loss.

A chair-type G-quadruplex structure formed by a human telomeric variant DNA in K+ solution

The chair-type G-quadruplex structure formed by human telomeric variant DNA.

Guanine tracts of human telomeric DNA sequences are known to fold into eight different four-stranded structures that vary by the conformation of guanine nucleotides arranged in the stack of G-tetrads in their core and by different kinds and orders of connecting loops, called G-quadruplexes. Here, we present a novel G-quadruplex structure formed in K⁺ solution by a human telomeric variant d[(GGGTTA)2GGGTTTGGG], htel21T₁₈. This variant DNA is located in the subtelomeric regions of human chromosomes 8, 11, 17, and 19 as well as in the DNase hypersensitive region and in the subcentromeric region of chromosome 5. Interestingly, single A18T substitution that makes htel21T₁₈ different from the human telomeric sequence results in the formation of a three-layer chair-type G-quadruplex, a fold previously unknown among human telomeric repeats, with two loops interacting through the reverse Watson–Crick A6·T18 base pair. The loops are edgewise; glycosidic conformation of guanines is syn·anti·syn·anti around each tetrad, and each strand of the core has two antiparallel adjacent strands. Our results expand the repertoire of known G-quadruplex folding topologies and may provide a potential target for structure-based anticancer drug design.

Effects of chronic dexamethasone exposure on bile acid metabolism and cecal epithelia function in goats

Bile acids (BAs) are synthesized in the liver via the oxidation of cholesterol and further metabolized by microbiota in the gut, where they simultaneously impact gut function. In the present study, 10 goats were randomly divided into 2 groups; 1 group was injected with dexamethasone (Dex; 0.2 mg/kg), and the other group was injected with saline as the control (Con) for 21 d. Expression levels of key genes and proteins in the liver and gut mucosa were analyzed and compared to investigate the impact of chronic stress on BA metabolism and related functions in ruminants. The results revealed that Dex decreased plasma total BAs (TBAs) concentration (P < 0.05) but increased TBA concentration in the cecal digesta (P < 0.05). Total cholesterol in the liver decreased moderately in response to Dex. The protein expression of cytochrome P450 family 7 subfamily A member 1 and cytochrome P450 family 27 subfamily A member 1, 2 enzymes that control BA synthesis in the liver, remained unchanged by Dex administration (P > 0.05). The expression of several genes in the cecal mucosa encoding epithelial tight junction proteins, including occludin (P < 0.05), tight junction protein 1 (P < 0.01), and claudin 1 (P < 0.05), increased significantly in response to Dex, and expression of defensin beta 1, which can strengthen the innate immune system, was also upregulated (P < 0.05). In addition, BAs increased the expression of the Solute Carrier family 9 member A 2 (P < 0.01) that encodes a sodium hydrogen exchanger. These results suggest that the Dex-induced disruption of BA homeostasis might be mediated through a liver-independent pathway in goats, and the Dex-induced accumulation of TBAs in the cecal digesta may improve volatile fatty acid transportation and mucosal defense.

Mortality and prognostic factors in Chinese patients with systemic lupus erythematosus

Objectives

To investigate the mortality and causes of death in Chinese patients with systemic lupus erythematosus.

Methods

We collected the clinical data of all consecutive adult systemic lupus erythematosus patients at the Rheumatology department of Peking University First Hospital between January 2007 and December 2015. The primary causes of death were identified, the standardized mortality ratio and years of life lost were calculated, and the survival and variables associated with mortality were determined by Kaplan–Meier and Cox regression analysis respectively.

Results

The mean age of all 911 patients (814 females and 97 males) was 37.8 ± 14.7 years, the median disease duration at recruitment was 2.6 (0.5–7.0) years, and the median follow-up duration was 3.0 (1.4–5.1) years. Among the 911 patients who were successfully followed up, 45 patients died. Infection (31.1%) was the leading cause of death followed by renal failure, pulmonary arterial hypertension and cerebrovascular diseases. The overall age and sex-adjusted standardized mortality ratio was 3.2 (95% confidence interval 2.4–4.0), and the years of life lost for women and men were 29.8 and 9.4 respectively. Overall survival at 1, 5 and 10 years was 98.2%, 95.3% and 93.7% respectively. Older age at disease onset, infection, autoimmune hemolytic anemia, thrombocytopenia and pulmonary arterial hypertension were independent risk factors for the mortality of systemic lupus erythematosus patients, and longer disease duration at recruitment was an independent protective factor.

Conclusions

Mortality of systemic lupus erythematosus patients in China was substantial, especially in females, with infection the leading cause of death. Older age at disease onset, infection, autoimmune hemolytic anemia, thrombocytopenia and pulmonary arterial hypertension were associated with poor outcomes.

All-optical multilevel amplitude regeneration in a single nonlinear optical loop mirror

We experimentally demonstrate all-optical amplitude regeneration of 4-level pulse amplitude modulated signals (PAM4) based on a single nonlinear optical loop mirror (NOLM). Four power-plateau regions are achieved using return-to-zero (RZ) pulses of narrow pulse-width, enabling large nonlinear phase shifts within the highly nonlinear fiber (HNLF). We quantify noise suppression characteristics at each amplitude level and obtain an overall EVM improvement of 0.92dB by optimizing input power and distortion strength. A theoretical analysis has been also carried out matching the experimental results and revealing the design characteristics of the regenerator's nonlinear transfer function.

Prognostic values of common clinical parameters in advanced pancreatic ductal adenocarcinoma: a large multicenter cohort study of ten years

OBJECTIVE

We conducted a multicenter cohort study to investigate the prognostic value of some commonly-used laboratory indices in advanced pancreatic ductal adenocarcinoma (PDAC).

METHODS

A multicenter cohort study was conducted from 2004 to 2013. The associations between laboratory indices and prognosis of advanced PDAC were examined.

RESULTS

This cohort consisted of 553 females (36.2%) and 973 males (63.8%). Patients at cancer stage III and IV were 595 (39.0%) and 931 (61.0%), respectively. The median survival of stage III patients was 9.0 months, with 3-, 6-, and 12-month survival rates of 94.5%, 73.4%, and 28.5%, respectively. The median survival of stage IV patients was 5.4 months, with 3-, 6-, and 12-month survival rates of 79.3%, 42.9%, and 15.0%, respectively. In multivariate analyses, primary tumor diameter, low albumin, and elevated CA19-9 were associated with decreased survival for stage III patients. Age, smoking, primary tumor diameter, elevated ALT or AST, low albumin, and elevated CA19-9 were associated with decreased survival for stage IV patients.

CONCLUSION

Elevated CA19-9 level, decreased albumin level, and tumor size were associated with worse survival in stage III patients. Meanwhile, advanced age, smoking, and ALT or AST level were negatively correlated to prognosis in stage IV patients.

Characterizations of distinct parallel and antiparallel G-quadruplexes formed by two-repeat ALS and FTD related GGGGCC sequence

The large expansion of GGGGCC (G4C2) repeats of the C9orf72 gene have been found to lead to the pathogenesis of devastating neurological diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The structural polymorphisms of C9orf72 HRE DNA and RNA may cause aberrant transcription and contribute to the development of ALS and FTD. Here we showed that the two-repeat G4C2 DNA, d(G4C2)₂, simultaneously formed parallel and antiparallel G-quadruplex conformations in the potassium solution. We separated different folds of d(G4C2)₂ by anion exchange chromatography, followed with characterizations by circular dichroism and nuclear magnetic resonance spectroscopy. The parallel d(G4C2)₂ G-quadruplex folded as a symmetric tetramer, while the antiparallel d(G4C2)₂ adopted the topology of an asymmetric dimer. These folds are distinct from the antiparallel chair-type conformation we previously identified for the d(G4C2)₄ G-quadruplex. Our findings have demonstrated the conformational heterogeneity of the C9orf72 HRE DNA, and provided new insights into the d(G4C2)_n folding. Meanwhile, the purified d(G4C2)₂ G-quadruplex samples are suitable for further three-dimensional structure characterizations, which are required for the structure-based design of small molecules targeting ALS and FTD related C9orf72 HRE.

Development of an Open Metadata Schema for Prospective Clinical Research (openPCR) in China

Objectives: In China, deployment of electronic data capture (EDC) and clinical data management system (CDMS) for clinical research (CR) is in its very early stage, and about 90% of clinical studies collected and submitted clinical data manually. This work aims to build an open metadata schema for Prospective Clinical Research (openPCR) in China based on openEHR archetypes, in order to help Chinese researchers easily create specific data entry templates for registration, study design and clinical data collection.

Methods: Singapore Framework for Dublin Core Application Profiles (DCAP) is used to develop openPCR and four steps such as defining the core functional requirements and deducing the core metadata items, developing archetype models, defining metadata terms and creating archetype records, and finally developing implementation syntax are followed.

Results: The core functional requirements are divided into three categories: requirements for research registration, requirements for trial design, and requirements for case report form (CRF). 74 metadata items are identified and their Chinese authority names are created. The minimum metadata set of openPCR includes 3 documents, 6 sections, 26 top level data groups, 32 lower data groups and 74 data elements. The top level container in openPCR is composed of public document, internal document and clinical document archetypes. A hierarchical structure of openPCR is established according to Data Structure of Electronic Health Record Architecture and Data Stand -ard of China (Chinese EHR Standard). Meta-data attributes are grouped into six parts: identification, definition, representation, relation, usage guides, and administration.

Discussions and Conclusion: OpenPCR is an open metadata schema based on research registration standards, standards of the Clinical Data Interchange Standards Consortium (CDISC) and Chinese healthcare related stand -ards, and is to be publicly available throughout China. It considers future integration of EHR and CR by adopting data structure and data terms in Chinese EHR Standard. Archetypes in openPCR are modularity models and can be separated, recombined, and reused. The authors recommend that the method to develop openPCR can be referenced by other countries when designing metadata schema of clinical research. In the next steps, openPCR should be used in a number of CR projects to test its applicability and to continuously improve its coverage. Besides, metadata schema for research protocol can be developed to structurize and standardize protocol, and syntactical interoperability of openPCR with other related standards can be considered.

Safety of Metformin Therapy in Patients with Type 2 Diabetes Living on an Oxygen-Deficient Plateau, Tibet, China

BACKGROUND

In the general population, the absolute risk of lactic acidosis in patients treated with metformin appears to be low. However, in the Tibetan plateau, an extreme oxygen-deficient environment, there are no data available concerning the safety of metformin. The aim of our study is to assess the safety of metformin in people of the plateau area.

METHODS

We conducted an observational cross-sectional study in Tibet. All the 166 subjects were divided into two groups: T2DM+metformin group and T2DM group. Clinical characteristics as well as lactate levels were measured in all subjects. The association between lactate, metformin use, FBG, HbA1c, eGFR, and other potential predictors was evaluated.

RESULTS

A total of 166 subjects were enrolled in this study. Average age was 51.7±12.3 years, and the percentage of male participants was 67%. The median level of lactate was 1.89 (1.35-2.91) mmol/L in all the subjects. The mean (±SD) lactate concentration in patients treated with metformin, versus those who were not, was 2.35±1.42 vs 2.29±1.65 mmol/L, respectively (mean difference 0.06 mmol/L, 95% CI: -0.48-0.60, P=0.556). FBG was significantly higher in the high lactate group than in the low lactate group (12.1±4.1 vs. 10.5±4.0 mmol/L, P=0.018). Similarly, HbA1c level was also significantly higher in the high lactate group than in the low lactate group (12.3±2.6 vs. 11.0±3.0%, P=0.008).

CONCLUSIONS

In the oxygen-deficient Tibetan plateau, lactate concentration among patients on metformin was not significantly different from patients without metformin. The level of lactate was significantly associated with FBG and HbA1c levels.