pH-Activatable Pre-Nanozyme Mediated H2S Delivery for Endo-Exogenous Regulation of Oxidative Stress in Acute Kidney Injury

Oxidative stress induced by excess reactive oxygen species (ROS) is a primary pathogenic cause of acute kidney injury (AKI). Development of an effective antioxidation system to mitigate oxidative stress for alleviating AKI remains to be investigated. This study presents the synthesis of an ultra-small Platinum (Pt) sulfur cluster (Pt5.65S), which functions as a pH-activatable prefabricated nanozyme (pre-nanozyme). This pre-nanozyme releases hydrogen sulfide (H2S) and transforms into a nanozyme (Ptzyme) that mimics various antioxidant enzymes, including superoxide dismutase and catalase, within the inflammatory microenvironment. Notably, the Pt5.65S pre-nanozyme exhibits an endo-exogenous synergy-enhanced antioxidant therapeutic mechanism. The Ptzyme reduces oxidative damage and inflammation, while the released H2S gas promotes proneurogenesis by activating Nrf2 and upregulating the expression of antioxidant molecules and enzymes. Consequently, the Pt5.65S pre-nanozyme shows cytoprotective effects against ROS/reactive nitrogen species (RNS)-mediated damage at remarkably low doses, significantly improving treatment efficacy in mouse models of kidney ischemia-reperfusion injury and cisplatin-induced AKI. Based on these findings, the H2S-generating pre-nanozyme may represent a promising therapeutic strategy for mitigating inflammatory diseases such as AKI and others.

Reaction Mechanisms and Kinetics of Nanozymes: Insights from Theory and Computation

"Nanozymes" usually refers to inorganic nanomaterials with enzyme-like catalytic activities. The research into nanozymes is one of the hot topics on the horizon of interdisciplinary science involving materials, chemistry, and biology. Although great progress has been made in the design, synthesis, characterization, and application of nanozymes, the study of the underlying microscopic mechanisms and kinetics is still not straightforward. Density functional theory (DFT) calculations compute the potential energy surfaces along the reaction coordinates for chemical reactions, which can give atomistic-level insights into the micro-mechanisms and kinetics for nanozymes. Therefore, DFT calculations have been playing an increasingly important role in exploring the mechanisms and kinetics for nanozymes in the past years. The calculations either predict the microscopic details for the catalytic processes to complement the experiments or further develop theoretical models to depict the physicochemical rules. In this review, the corresponding research progress is summarized. Particularly, the review focuses on the computational studies that closely interplay with the experiments. The relevant experimental results without DFT calculations will be also briefly discussed to offer a historic overview of how the computations promote the understanding of the microscopic mechanisms and kinetics of nanozymes.

Employing Noble Metal-Porphyrins to Engineer Robust and Highly Active Single-Atom Nanozymes for Targeted Catalytic Therapy in Nasopharyngeal Carcinoma

Single-atom nanozymes (SANzymes) emerge as promising alternatives to conventional enzymes. However, chemical instability limits their application. Here, a systematic synthesis of highly active and stable SANzymes is presented by leveraging noble metal-porphyrins. Four noble metal-porphyrins are successfully synthesized to mimic the active site of natural peroxidases through atomic metal-N coordination anchored to the porphyrin center. These noble metal-porphyrins are integrated into a stable and biocompatible Zr-based metal-organic framework (MxP, x denoting Ir, Ru, Pt, and Pd). Among these, MIrP demonstrates superior peroxidase-like activity (685.61 U mg-1 ), catalytic efficiency, and selectivity compared to horseradish peroxidase (267.71 U mg-1 ). Mechanistic investigations unveil heightened catalytic activity of MIrP arises from its robust H2 O2 adsorption capacity, unique rate-determining step, and low energy threshold. Crucially, MIrP exhibits remarkable chemical stability under both room temperature and high H2 O2 concentrations. Further, through modification with (-)-Epigallocatechin-3-Gallate, a natural ligand for Epstein-Barr virus (EBV)-encoded latent membrane protein 1, targeted SANzyme (MIrPHE) tailored for EBV-associated nasopharyngeal carcinoma is engineered. This study not only presents an innovative strategy for augmenting the catalytic activity and chemical stability of SANzymes but also highlights the substantial potential of MIrP as a potent nanomedicine for targeted catalytic tumor therapy.

Cascade nanozymatic network mimicking cells with selective and linear perception of H2O2

A single stimulus leading to multiple responses is an essential function of many biological networks, which enable complex life activities. However, it is challenging to duplicate a similar chemical reaction network (CRN) using non-living chemicals, aiming at the disclosure of the origin of life. Herein, we report a nanozyme-based CRN with feedback and feedforward functions for the first time. It demonstrates multiple responses at different modes and intensities upon a single H₂O₂ stimulus. In the two-electron cascade oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), the endogenous product H₂O₂ competitively inhibited substrates in the first one-electron oxidation reaction on a single-atom nanozyme (Co-N-CNTs) and strikingly accelerated the second one-electron oxidation reaction under a micellar nanozyme. As a proof-of-concept, we further confined the nanozymatic network to a microfluidic chip as a simplified artificial cell. It exhibited remarkable selectivity and linearity in the perception of H₂O₂ stimulus against more than 20 interferences in a wide range of concentrations (0.01-100 mM) and offered an instructive platform for studying primordial life-like processes.

Clear-Box Machine Learning for Virtual Screening of 2D Nanozymes to Target Tumor Hydrogen Peroxide

Targeting tumor hydrogen peroxide (H₂ O₂ ) with catalytic materials has provided a novel chemotherapy strategy against solid tumors. Because numerous materials have been fabricated so far, there is an urgent need for an efficient in silico method, which can automatically screen out appropriate candidates from materials libraries for further therapeutic evaluation. In this work, adsorption-energy-based descriptors and criteria are developed for the catalase-like activities of materials surfaces. The result enables a comprehensive prediction of H₂ O₂ -targeted catalytic activities of materials by density functional theory (DFT) calculations. To expedite the prediction, machine learning models, which efficiently calculate the adsorption energies for 2D materials without DFT, are further developed. The finally obtained method takes advantage of both interpretability of physics model and high efficiency of machine learning. It provides an efficient approach for in silico screening of 2D materials toward tumor catalytic therapy, and it will greatly promote the development of catalytic nanomaterials for medical applications.

[Determination of chlorobenzene metabolite-p-chlorophenol in urine by solid phase extraction-gas chromatography]

Objective: A method to determine chlorobenzene metabolite-p-chlorophenol in urine by solid phase extraction-gas chromatography was established. Methods: In May 2021, the urine sample was hydrolyzed at 100 ℃ for 1.5 h with 2 ml concentrated hydrochloric acid. After cooling and filtering, the sample was enriched and purified by Oasis(®)MAX 6cc SPE column. Drip washing with 0.01 mol/L hydrochloric acid solution and elution with acetonitrile, the eluent was volumized to 5 ml with acetonitrile and determined by gas chromatography, and quantify by standard curve method. Results: Calibration curve of the method was linear within the range of 1.61-80.30 μg/ml and showed good linearity with r=0.9997, the regression equation was y=1.51602x-0.10234. The determination limit was 0.17 μg/ml, and the limit of quantitation was 0.55 μg/ml. Recovery rates were between 89.3%-104.4%, the relative standard deviation (RSD) of intra-day measurements ranged from 4.3% to 6.7%, and the RSD of inter-day measurements ranged from 4.5% to 6.7%. Conclusion: This method could optimize sample pretreatment, and eliminate the interference of impurities, which is sensitive, efficient and accurate for the determination of chlorobenzene metabolite-p-chlorophenol in urine.

[Efficiency and safety of peptide receptor radionuclide therapy in the treatment of metastatic neuroendocrine tumors]

The clinical data of 14 patients with neuroendocrine tumors who received Peptide Receptor Radionuclide Therapy (PRRT) from December 2018 to May 2021 were retrospectively analyzed. Among them, 2 patients demonstrated proprogressive disease, 2 patients had partial response, and 10 patients had stable disease. Grade 1-2 myelosuppression occurred in 5 patients. and 1 patient became grade 3 myelosuppression，which recovered to grade 2 after symptomatic treatment. No grade 2 or higher treatment-related renal toxicity was observed in any of the patients. PRRT is efficacy and no significant side effects for unresectable metastatic neuroendocrine tumors.

Metastable Iron Sulfides Gram-Dependently Counteract Resistant Gardnerella Vaginalis for Bacterial Vaginosis Treatment

Bacterial vaginosis (BV) is the most common vaginal infection found in women in the world. Due to increasing drug-resistance of virulent pathogen such as Gardnerella vaginalis (G. vaginalis), more than half of BV patients suffer recurrence after antibotics treatment. Here, metastable iron sulfides (mFeS) act in a Gram-dependent manner to kill bacteria, with the ability to counteract resistant G. vaginalis for BV treatment. With screening of iron sulfide minerals, metastable Fe₃ S₄ shows suppressive effect on bacterial growth with an order: Gram-variable G. vaginalis >Gram-negative bacteria>> Gram-positive bacteria. Further studies on mechanism of action (MoA) discover that the polysulfide species released from Fe₃ S₄ selectively permeate bacteria with thin wall and subsequently interrupt energy metabolism by inhibiting glucokinase in glycolysis, and is further synergized by simultaneously released ferrous iron that induces bactericidal damage. Such multiple MoAs enable Fe₃ S₄ to counteract G. vaginalis strains with metronidazole-resistance and persisters in biofilm or intracellular vacuole, without developing new drug resistance and killing probiotic bacteria. The Fe₃ S₄ regimens successfully ameliorate BV with resistant G. vaginalis in mouse models and eliminate pathogens from patients suffering BV. Collectively, mFeS represent an antibacterial alternative with distinct MoA able to treat challenged BV and improve women health.

TiO2 supported single Ag atoms nanozyme for elimination of SARS-CoV2

The outbreak of SARS-coronavirus 2 (SARS-CoV2) has become a global health emergency. Although enormous efforts have been made, there is still no effective treatment against the new virus. Herein, a TiO₂ supported single-atom nanozyme containing atomically dispersed Ag atoms (Ag-TiO₂ SAN) is designed to serve as a highly efficient antiviral nanomaterial. Compared with traditional nano-TiO₂ and Ag, Ag-TiO₂ SAN exhibits higher adsorption (99.65%) of SARS-CoV2 pseudovirus. This adsorption ability is due to the interaction between SAN and receptor binding domain (RBD) of spike 1 protein of SARS-CoV2. Theoretical calculation and experimental evidences indicate that the Ag atoms of SAN strongly bind to cysteine and asparagine, which are the most abundant amino acids on the surface of spike 1 RBD. After binding to the virus, the SAN/virus complex is typically phagocytosed by macrophages and colocalized with lysosomes. Interestingly, Ag-TiO₂ SAN possesses high peroxidase-like activity responsible for reactive oxygen species production under acid conditions. The highly acidic microenvironment of lysosomes could favor oxygen reduction reaction process to eliminate the virus. With hACE2 transgenic mice, Ag-TiO₂ SAN showed efficient anti-SARS-CoV2 pseudovirus activity. In conclusion, Ag-TiO₂ SAN is a promising nanomaterial to achieve effective antiviral effects for SARS-CoV2.

[Insist principles of medical science, boycott illegal or inappropriate "tooth beauty"]

Regarding the illegal performance of "tooth beauty" and the mal-practice in aesthetic dentistry, the author proposed boycotts and solutions that were making clear of the property and forming professional guidelines, getting supports from administrations by fully communication, enhancing oral health education, promoting self-discipline within professions, and standing firmly on medical profession morals.

[Dose-response relationship between noise kurtosis and noise-induced hearing loss]

Objective: To analyse the dose-response relationships between the kurtosis metric of noise and noise-induced hearing loss (NIHL) and study the role of kurtosis in the evaluation of NIHL associated with non-Gaussian noise. Methods: From January 2012 to December 2017, a total of 1869 workers in seven manufacturing industries were selected as the study subjects. The basic data of the workers were investigated by questionnaire, personal noise waveform was collected for a long time, and pure tone hearing threshold was tested. The 8-hour continuous equivalent A sound level (L(Aeq, 8 h)) , cumulative noise exposure (CNE) and kurtosis structure indexes were calculated. The dose-response relationships between kurtosis and NIHL were analyzed by stratification analysis method, which controlled the influence of CNE, L(Aeq, 8 h), exposure duration, age and sex on hearing loss using high-frequency noise-induced permanent threshold shift (NIPTS(346)) and high-frequency noise-induced hearing loss (HFNIHL) as outcome indicators. Results: When CNE was <90 dB (A) ·year and ≥100 dB (A) ·year, NIPTS(346) in the extremely high kurtosis group was significantly greater than that in the Gaussian kurtosis, low kurtosis and medium kurtosis group (P<0.05) . In the workers exposed to L(Aeq, 8 h)<85 dB (A) and ≥94 dB (A) , NIPTS(346) in the extremely high kurtosis group was significantly greater than that in the Gaussian kurtosis group (P<0.05) . Among workers under the age of 50 or male workers, NIPTS(346) in the extremely high kurtosis group was significantly greater than that in the Gaussian kurtosis, low kurtosis and medium kurtosis group (P<0.05) . Kurtosis was positively correlated with NIPTS(346) (r=0.121, P<0.05) . When CNE was <100 dB (A) ·year, the detection rate of HFNIHL increased with the increase of kurtosis level (P<0.01) . Logistic regression analysis showed that kurtosis was an important influencing factor for HFNIHL (OR=1.321) . Conclusion: Kurtosis has a dose-response relationship with the detection rate of HFNIHL in noise exposed workers, and noise kurtosis is an influencing factor of NIHL.

A GGA + U investigation into the effects of cations on the electromagnetic properties of transition metal spinels

Spinel oxides are promising low-cost catalysts with manifold and controllable physicochemical properties. Trial and error strategies cannot achieve the effective screening of high-performance spinel catalysts. Therefore, unraveling the structure–performance relationship is the foundation for their rational design. Herein, the effects of cations in tetrahedral and octahedral sites on the electronic structures of spinels were systematically investigated using GGA + U calculations based on ACr₂O₄ (A = Mn, Fe, Co, Ni, and Zn) and Zn/LiB₂O₄ (B = Cr, Mn, Fe, Co and Ni). The results indicate that the octahedrally coordinated B cations have notable influence on the electronic structures of spinels. The Jahn–Teller active ions Fe²⁺, Ni²⁺, Mn³⁺, Ni³⁺, Cr⁴⁺ and Fe⁴⁺ can remarkably reduce the band gaps of spinels and even change their electroconductibilities. These results will provide theoretical insights into the electronic properties of 3d transition metal spinels.

Jahn–Teller active ions Fe²⁺, Ni²⁺, Mn³⁺, Ni³⁺, Cr⁴⁺ and Fe⁴⁺ can effectually regulate the electronic structures of transition metal spinels.

[Effect of digital virtual simulation system for preclinical teaching of access and coronal cavity preparation]

Objective: To investigate the effectiveness of a digital virtual simulation training system applied in the preclinical teaching of access and coronal cavity preparation. Methods: Twenty dental undergraduate students from Peking University School and Hospital of Stomatology were recruited and divided randomly and equally into two groups according to the random number method after being unified with theory training, including access and coronal cavity preparation skills assessment form and Simodont system operation manual. Tests for access and coronal cavity preparation skills by using standard simulation plastic teeth were performed and the scores were recorded as baseline for each student. Students in group of virtual simulation priority were trained using Simodont virtual simulation system, while those in group of phantom-simulator priority were trained using conventional phantom-simulator system. Access and coronal cavity preparation skills of standard simulation plastic teeth were assessed once again and recorded as the second scores for the two groups. Furthermore, the two groups of students exchanged training systems and were assessed and graded once more as the third scores. Finally, all students were asked to fill up a Teaching Questionnaire after the training. The data were then collected and analyzed. Results: For the group of virtual simulation priority, after the training by using Simodont virtual simulation system and conventional phantom-simulator system, the mean score of access and coronal cavity preparation (16.00±1.49) was significantly higher than the baseline score (13.30±1.41) (P<0.05). For the group of phantom-simulator priority, after the training by using conventional phantom-simulator system and Simodont virtual simulation system, the mean score of access and coronal cavity preparation (15.60±1.26) was also significantly higher than the baseline score (13.00±1.89) (P<0.05). Furthermore, in the group of virtual simulation priority, of which the students were trained by using Simodont virtual simulation system first and then conventional phantom-simulator system, the score of access and coronal cavity preparation was significantly higher than the score of training by using conventional phantom-simulator system only (14.30±1.77) (P<0.05). In the group of phantom-simulator priority, of which the students were trained by using conventional phantom-simulator system first and then Simodont virtual simulation system, the score of access and coronal cavity preparation was significantly higher than the score of training by using Simodont virtual simulation system only (14.10±1.45) (P<0.05). Moreover, in the group of virtual simulation priority, the score of training by using conventional phantom-simulator system after using Simodont virtual simulation system was significantly higher than that of training by using Simodont virtual simulation system only (P<0.05). The results of the questionnaire showed that the students fully agreed that "the Simodont virtual simulation system has the characteristics of repeatability, multi-dimension and multiple practice, and provides me with more attention to details" [80% (16/20)], however "it needs to be improved and upgraded to be close to the conventiaonl phantom-simulator system" [90% (18/20)]. Conclusions: Compared with using the conventional phantom-simulator system only, the preclinical teaching effectiveness of access and coronal cavity preparation could be effectively improved by using Simodont virtual simulation system combined with the phantom-simulator training system and might influenced by the training sequence.

[Clinical analysis of 14 infective endocarditis in patients with obstructive hypertrophic cardiomyopathy]

Objective: This observational study was aimed to analyze the clinical characteristics of infective endocarditis (IE) in patients with hypertrophic cardiomyopathy (HCM). Methods: A total of 668 patients with IE, and 7 427 patients with HCM were treated in Fuwai Hospital from August 2006 to December 2018. Among them, 14 patients were diagnosed with HCM and IE. The clinical characteristics of these patients including clinical manifestations, pathogen distribution, echocardiography features, in-hospital treatment and outcomes were analyzed retrospectively. Results: The proportion of HCM patients with IE was 0.19%,with the estimated incidence of 0.15/1 000 person-years in HCM patients. Of the 14 patients, 11 patients were male. The most common clinical manifestations were fever and heart murmur, and the main complications were heart failure (12/14) and bacterial embolism (8/14). There were 8 cases (8/14) with positive blood culture, and all causative bacteria were gram positive coccus, in which 5/8 were Streptococcus. The median interventricular septum thickness was (21.2±2.7) mm, and left ventricular outflow obstruction was severe based on echocardiography (Echo) examination. The Echo showed that vegetation was found in all 14 patients and most of the vegetation attached at the anterior leaflet of mitral valve (12/14). The proportions of patients with circulatory embolism (8/14) and valve lesions (12/14) were relatively high. Most cases (10/14) were cured, especially those underwent cardiac surgery (8 cases). The rest 4 cases died with 2 in hospital and 2 after auto-discharge. Conclusions: HCM patients complicated with IE are rare. Septic embolization and valve lesions are common in these patients. IE patients with HCM might have a poor prognosis compared to those without HCM and should receive cardiac surgery as early as possible.

Origins of the peroxidase mimicking activities of graphene oxide from first principles

Graphene-based nanomaterials, including graphene oxide (GO) and reduced graphene oxide (rGO), play key roles in the nanozyme field. GO and rGO carrying various oxygen-containing functional groups, including epoxy, hydroxyl, ether, endoperoxide, carbonyl, carboxyl, and ester, have been reported to display peroxidase mimicking activities. However, the active center and the underlying mechanism responsible for its peroxidase mimicking activities still remain unclear. Herein, taking the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) by H2O2 as the model reaction, we investigate the possible catalytic mechanisms using DFT calculations. The results indicate that the carbonyl groups are the active centers. The activation of the C[double bond, length as m-dash]O bond is the key step in the catalytic cycle. The results will help realize the rational design of carbon-based nanozymes.

A biomimetic platelet based on assembling peptides initiates artificial coagulation

Platelets play a critical role in the regulation of coagulation, one of the essential processes in life, attracting great attention. However, mimicking platelets for in vivo artificial coagulation is still a great challenge due to the complexity of the process. Here, we design platelet-like nanoparticles (pNPs) based on self-assembled peptides that initiate coagulation and form clots in blood vessels. The pNPs first bind specifically to a membrane glycoprotein (i.e., CD105) overexpressed on angiogenetic endothelial cells in the tumor site and simultaneously transform into activated platelet-like nanofibers (apNFs) through ligand-receptor interactions. Next, the apNFs expose more binding sites and recruit and activate additional pNPs, forming artificial clots in both phantom and animal models. The pNPs are proven to be safe in mice without systemic coagulation. The self-assembling peptides mimic platelets and achieve artificial coagulation in vivo, thus providing a promising therapeutic strategy for tumors.

[Clinical analysis of 12 cases of mixed connective tissue disease-associated trigeminal neuropathy]

Objective: The aim of present study is to analyze clinical and laboratory features of mixed connective tissue disease (MCTD)-associated trigeminal neuropathy (TN). Methods: Clinical records of 12 cases of MCTD complicated with TN diagnosed in Peking University People's Hospital from January 2008 to October 2019 were analyzed retrospectively. Results: The present study included 12 cases, 1 males and 11 females, average age was(40±13)years. TN was developed before the diagosis of MCTD in 1 case. TN and MCTD were occurred simutaneously in 1 case. Raynaud phenomenon (12 cases), arthritis (10cases), edema of fingers (9cases), myositis (6 cases), and pulmonary involvement (11cases) were main cinical feature of MCTD-associate TN. Antinuclear antibody (ANA) and high titer anti-U1-RNP antibody could be detected in serum of all patients. Elevated erythrocyte sedimentation rate (ESR) and creatine kinase were found in serum of 7cases and 5cases, respectively. Blink reflex tests were positive in 6 cases. Neurological symptoms improve slowly without any progress by using glucocorticoid combined immunosuppressants or intravenous gamma globulin. Conclusions: TN is often associted with actived MCTD. Positive ANA and anti-U1-RNP antibody were common in MCTD-associated TN. Blink reflex test is essential to diagnose MCTD-associated TN. Intensive treatment of MCTD contributes to control the progress of TN.

PCNA and GSK3β interact with each other to regulate H1299 lung adenocarcinoma cells apoptosis

Glycogen synthase kinase beta (GSK3β) is considered as a promising target for lung cancer treatment and its inhibitor lithium chloride (LiCl) is widely regarded as having potent anti-proliferative and apoptosis-modulating activities. Proliferating cell nuclear antigen (PCNA), as an auxiliary protein for DNA polymerase delta, which regulates DNA replication and repair, has been reported to play an important role in regulating apoptosis. Here, we showed that GSK3β interacted with PCNA in H1299 lung adenocarcinoma cells using GST pull-down and co-immunoprecipitation experiments. We discovered that their interaction can be enhanced within the first 3 h after UVC irradiation and decreased gradually with time. Overexpression of PCNA protein decreased GSK3β Ser9 phosphorylation, whereas knockdown of PCNA using small interfering RNA (siRNA) increased Ser9 phosphorylated GSK3β, which was attenuated by phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 after UVC irradiation, indicating the involvement of the PI3K-AKT pathway. Functional analyses suggested that downregulation of PCNA sensitized H1299 cells to LiCl-induced apoptosis. Thus, our results unraveled a novel regulatory of GSK3β by PCNA and provided a promising direction for treatment of lung cancer.

P825Long-term clinical benefit of atorvastatin pretreatment before primary percutaneous coronary intervention in patients with STEMI: a multi-center propensity score-matched study

Aims

We aim to investigate the effect of single dose of statin pretreatment prior to primary Percutaneous Coronary Intervention (PCI) on long-term clinical outcomes in patients with ST-elevation Myocardial Infarction (STEMI).

Methods

Using data from China Acute myocardial Infarction (CAMI) registry, we compared the outcome in STEMI patients with vs without atorvastation pretreatment prior to primary PCI. The primary endpoint was the composite outcome of all-cause mortality, non-fatal MI or stroke events during follow-up. Propensity-score (PS) matching was used to assemble a cohort of patients with similar baseline characteristics. All patients were followed till 24 months since baseline.

Results

Of all 3772 patients who met our inclusion criteria at 108 hospitals in China, 3288 patients (1644 patients in each arm) were included in our PS-matched cohort. In the PS-match cohort, overall 144 (8.65%) and 113 (6.79%) patients in the control group and pretreatment group had the primary endpoint respectively (p=0.048). The estimated HRs were 0.78 (95% CI: 0.606–0.997, p=0.046) in the unadjusted model and 0.76 (95% CI: 0.596–0.984, p=0.032) in the adjusted model (Figure). The HRs were broadly similar for the pretreatment dosage of 40 mg or 80 mg (0.78 vs 0.77, p=0.75). The HRs were even stronger in patients with single-vessel only than multi-vessel coronary artery disease (0.31 vs 0.75, p=0.014).

Conclusion

Among Chinese patients with STEMI, atorvastatin pretreatment before primary PCI may have better long-term composite outcome of all-cause mortality, non-fatal MI, or stroke events.

Acknowledgement/Funding

CAMS Innovation Fund for Medical Sciences (CIFMS) (2016-I2M-1-009)

P4622Prediction of in-hospital bleeding for AMI patients undergoing PCI using machine learning method

Background

Prediction of in-hospital bleeding is critical for clinical decision making for acute myocardial infarction (AMI) patients undergoing percutaneous coronary intervention (PCI). Machine learning methods can automatically select the combination of the important features and learn their underlying relationship with the outcome.

Objective

We aim to evaluate the predictive value of machine learning methods to predict in-hospital bleeding for AMI patients.

Methods

We used data from the multicenter China Acute Myocardial Infarction (CAMI) registry. We randomly partitioned the cohort into derivation set (75%) and validation set (25%). Using data from the derivation set, we applied a state-of-art machine learning algorithm, XGBoost, to automatically select features from 106 candidate variables and train a risk prediction model to predict in-hospital bleeding (BARC 3, 5 definition).

Results

16736 AMI patients who underwent PCI were consecutively included in the analysis, while 70 (0.42%) patients had in-hospital bleeding followed the BARC 3,5 definition of bleeding. Fifty-nine features were automatically selected from the candidate features and were used to construct the prediction model. The area under the curve (AUC) of the XGBoost model was 0.816 (95% CI: 0.745–0.887) on the validation set, while AUC of the CRUSADE risk score was 0.723 (95% CI: 0.619–0.828).

Relative contribution of the 12 most important features Feature Relative Importance Direct bilirubin 0.078 Heart rate 0.077 CKMB 0.076 Creatinine 0.064 GPT 0.052 Age 0.048 SBP 0.036 TG 0.035 Glucose 0.035 HCT 0.031 Total bilirubin 0.030 Neutrophil 0.030

ROC of the XGBoost model and CRUSADE

Conclusion

The XGBoost model derived from the CAMI cohort accurately predicts in-hospital bleeding among Chinese AMI patients undergoing PCI.

Acknowledgement/Funding

the CAMS innovation Fund for Medical Sciences (CIFMS) (2016-12M-1-009); the Twelfth Five-year Planning Project of China (2011BAI11B02)

P4629Long-term outcomes in patients with ST-segment elevation myocardial infarction according to modalities of reperfusion therapy: data from china acute myocardial infarction (CAMI) registry

Background

Although primary percutaneous coronary intervention (pPCI) is the optimal reperfusion method for ST-segment elevation myocardial infarction (STEMI), it remains difficult to implement in many areas. Some STEMI patients have to accept fibrinolytic therapy and no reperfusion therapy instead.

Purpose

The aim of this study was to describe the impact of reperfusion therapy on the long-term outcomes of STEMI patients in China.

Methods

Using data from the China Acute Myocardial Infarction (CAMI) registry, we analyzed the 2-year outcomes of 18,075 STEMI patients symptom onset within 7 days from January 2013 to September 2014 according to the type of reperfusion therapy. The primary endpoint was a composite of major adverse cardiovascular event (MACE), defined as all-cause mortality, myocardial infarction or stroke.

Results

7798 (43%) were treated with pPCI and 1798 (10%) underwent fibrinolysis; 8479 (47%) did not receive any reperfusion. The 2-year MACE was 9.6% following pPCI, 15.7% following fibrinolysis, and 21.5% for patients without reperfusion therapy (P<0.0001). Adjusted hazard ratios for 2-year MACE were 0.71 (95% confidence interval [CI] 0.65–0.78, P<0.0001) for pPCI versus no reperfusion and 0.92 (95% CI 0.82–1.03, P=0.16) for fibrinolysis versus no reperfusion. Compared with patients without reperfusion, fibrinolysis only showed benefit in patients presented within 3 hours of symptom onset (HR 0.70, 95% CI 0.57–0.85, P=0.0005), whereas pPCI was associated with significantly decreased 2-year MACE rate in patients presented within 3 hours (HR 0.53, 95% CI 0.44–0.64, P<0.0001), 3–6 hours (HR 0.60, 95% CI 0.51–0.71, P<0.0001) and >6 hours (HR 0.86, 95% CI 0.76–0.97, P=0.01) of symptom onset.

Adjusted cumulative MACE rate

Conclusions

In a real-world setting, early reperfusion is the optimal strategy for STEMI. Fibrinolysis was not associated with better outcome in STEMI patients admitted >3 hours of symptom onset in Chinese real world setting.

Acknowledgement/Funding

Ministry of Science and Technology of China (Grant No. 2011BAI11B02)

[Analysis on the short-term outcome of patients with acute myocardial infarction complicating cardiogenic shock due to left main disease]

Objective: To investigate the short-term outcome of patients with acute myocardial infarction complicating cardiogenic shock due to left main disease. Methods: A total of 24 patients with acute myocardial infarction complicating cardiogenic shock due to left main artery disease hospitalized in Fuwai hospital from June 2012 to May 2018 were included. The clinical data were analyzed,and the patients were divided into survivor group (11 cases) and death group (13 cases) according to survival status at 28 days post the diagnosis of shock. The patients were further divided into thrombolysis in myocardial infarction(TIMI) flow grade 0-2 group (11 cases) and TIMI flow grade 3 group (13 cases) according to TIMI flow grade after the procedure. The patients were then divided into non-three-vessel lesions group (14 cases) and three-vessel lesions group (10 cases) according to coronary angiography results. Results: Compared with survivor group, patients in death group presented with lower worst systolic blood pressure within 24 hours after admission (50(48, 70) mmHg (1 mmHg=0.133 kPa) vs. 73(70, 80) mmHg, P<0.01), lower worst diastolic blood pressure with in 24 hours after admission ((33.5±12.4) mmHg vs. (48.9±9.4) mmHg, P<0.01), higher respiratory rates ((27.3±2.5) times/min vs. (21.5±4.0) times/min, P<0.01), less 24 hours urine output ((422±266) ml vs. (1 680±863) ml, P<0.01), lower platelet counts ((161.9±81.9)×10(9)/L vs. (241.6±94.0)×10(9)/L, P=0.03), higher serum creatinine ((250.0±36.8) μmol/L vs. (132.7±34.2) μmol/L, P<0.01), higher alanine aminotransferase (288(76,846) IU/ml vs. 81(42, 109) IU/ml, P=0.04), lower artery pH (7.11±0.17 vs. 7.39±0.09, P<0.01), higher lactic acid ((10.29±3.62) mmol/L vs. (4.21±2.85) mmol/L, P<0.01), higher incidence of invasive ventilation (7/13 vs. 2/11, P=0.02), higher scores of acute physiology and chronic health evaluation (APACHE) Ⅱ (35.4±6.8 vs. 18.7±1.7, P<0.01) and simplified acute physiology score (SAPS) Ⅱ (73.5±17.4 vs. 47.0±4.3, P<0.01), and higher incidence of target vessel TIMI flow grade 0-2 (10/13 vs. 1/11, P<0.01). Kaplan-Meier survival curve analysis showed that survival rate at 28 days post the diagnosis of shock in TIMI flow grade 3 group was higher than that in TIMI flow grade 0-2 group (76.9% vs. 9.1%, log-rank test, P<0.01), and mortality rate was similar at 28 days post the diagnosis of shock between non-three-vessel lesions group and three-vessel lesions group (35.7% vs. 60.0%, log-rank test, P=0.14). Multivariate logistic regression analysis showed that compared with TIMI flow grade 0-2 group, the OR value of death at 28 days post the diagnosis of shock in TIMI flow grade 3 patients with acute myocardial infarction complicating cardiogenic shock due to left main disease was 0.030(95%CI 0.003-0.340, P<0.01). Conclusion: Short-term outcomeof patients with acute myocardial infarction complicating cardiogenic shock due to left main disease remains poor, and final flow of TIMI grade 3 is confirmed as independent protective factor of death at 28 days post the diagnosis of shock in these patients.

[Prognostic value of TIMI and GRACE risk scores for in-hospital mortality in Chinese patients with non-ST-segment elevation myocardial infarction]

Objective: To evaluate the prognostic value of the thrombolysis in myocardial infarction (TIMI) and global registry of acute coronary events (GRACE) risk scores for in-hospital mortality in Chinese non-ST-segment elevation myocardial infarction (NSTEMI) patients. Methods: Data of present study derived from the prospective, multi-center registry trial of Chinese AMI (CAMI). Among 31 provinces, municipalities or autonomous districts in China, at least one tertiary and secondary hospital was selected. From January 2013 to September 2014, 5 896 consecutive non-ST-segment elevation myocardial infarction patients who were admitted to 107 hospitals within 7 days of symptom onset were enrolled. For each patient, TIMI and GRACE risk scores were calculated using specific variables collected at admission. Their prognostic value was evaluated by the endpoint of in-hospital mortality. Results: Among 5 896 NSTEMI patients (age was (65.4±12.1) years old), 68.2% (n=4 020) were males. The in-hospital mortality was 6.0% (n=353) and the median length of hospital stay was 10.0 (7.0, 13.0) days. The incidence of pre-hospital cardiac arrest was 3.6% (n=213) among 5 896 NSTEMI patients. Six hundreds and forty five patients (10.9%) received primary percutaneous coronary intervention, and 6 patients underwent emergent coronary artery bypass grafting surgery (0.1%), and the median time of reperfusion was 529.5 (256.0, 1 065.0) minutes. The prescription percentage of statins, β-blocker, angiotensin converting enzyme inhibitors or angiotensin Ⅱ receptor blockers, and aldosterone antagonists were 94.8% (n=5 587), 71.7% (n=4 228), 65.5% (n=3 864) and 26.0% (n=1 533) respectively. The area under the curve of GRACE risk score for in-hospital mortality (0.7930 (95%CI 0.767-0.818)) was better than that of TIMI risk score (0.5588 (95%CI 0.532-0.586), P<0.001). Conclusion: GRACE risk score demonstrates better predictive accuracy than TIMI risk score for in-hospital mortality in NSTEMI patients in this patient cohort.

Dioxygen activation with stable N-heterocyclic carbenes

Dioxygen activation with both cyclic (amino)(alkyl)carbenes and di(amino)carbenes at ambient temperature is described.

Computed tomography-quantified body composition predicts short-term outcomes after gastrectomy in gastric cancer

Background

Malnutrition is a common and critical problem that influences outcome in cancer patients. Body composition reflects a patient's metabolic profile and physiologic reserves, which might be the true determinant of prognosis. In the present study, which aimed to identify valuable new prognostic indicators, we investigated the association between computed tomography-quantified body composition and short-term outcomes after gastrectomy for gastric cancer.

Methods

Skeletal muscle index, mean muscle attenuation, and ratio of visceral-to-subcutaneous adipose tissue area (vsr) were calculated from preoperative computed tomography images. Low skeletal muscle index, low mean muscle attenuation, and high vsr were respectively termed "sarcopenia," "myosteatosis," and "visceral obesity." The association of body composition with postoperative complications and serum markers of nutrition and inflammation after radical gastrectomy were analyzed.

Results

The overall complication rate was significantly higher in the sarcopenia (62.5% vs. 27.3%, p = 0.001) and myosteatosis groups (38.2% vs. 4%, p = 0.002). Patients with visceral obesity had a higher incidence of inflammatory complications (20.3% vs. 6.5%, p = 0.01). Multivariate logistic regression analysis demonstrated that sarcopenia (p = 0.013), myosteatosis (p = 0.017), and low serum retinol-binding protein (p = 0.019) were independent risk factors for overall complications. Compared with control subjects, patients with sarcopenia had lower postoperative levels of serum retinol-binding protein (p = 0.007), and patients with visceral obesity had higher levels of C-reactive protein (p = 0.026).

Conclusions

Sarcopenia, myosteatosis, and visceral obesity were significantly associated with increased rates of postoperative complications and affected the postoperative nutrition and inflammation status of patients with gastric cancer.

[Comparison on the predictive value of different scoring systems for risk of short-term death in patients with acute myocardial infarction complicating cardiogenic shock]

Objective: To compare predictive value of the current 7 scoring systems and CADILLAC-plus scoring system for risk of short-term deathin patients with acute myocardial infarction complicating cardiogenic shock. Methods: A total of 126 acute myocardial infarction patients complicating cardiogenic shock hospitalized in Fuwai hospital from June 2014 to January 2018 were enrolled in this study, the clinical data were retrospectively analyzed. The patients were divided into survival group(49 cases) and death group(77 cases) according to survival or not at 28 days after diagnosis of cardiogenic shock.The scores of APACHE Ⅱ,APACHE Ⅲ,SAPS Ⅱ,PAMI, TIMI-STEMI,TIMI-NSTEMI,and CADILLAC were calculated within 24 hours in coronary care unit (CCU),and scores of CADILLAC-plus, which is an improved score derived from CADILLAC, was also calculated. The predictive value of the different scoring systems for 28 day smortality of acute myocardial infarction patients complicating cardiogenic shock were compared in this patient cohort. Results: Scores of APACHEⅡ,APACHEⅢ,SAPSⅡ,PAMI,TIMI-STEMI, TIMI-NSTEMI,CADILLAC,and CADILLAC-plus were all significantly higher in death group than in survival group: (28.9±10.2 vs. 21.8±8.3,94.0 (57.0,114.0) vs. 57.0 (45.4,81.5) ,62.0 (46.0,81.0) vs. 47.0 (41.5,60.5) ,7.0 (6.0,9.0) vs. 6.0 (6.0,7.5) ,10.0 (9.0,11.0) vs. 9.0 (8.0,10.0) ,4.0 (3.0,5.0) vs. 3.0 (3.0,4.0) ,10.0 (7.0,12.0) vs. 7.0 (5.0,9.0) ,and 10.0 (8.0,14.0) vs. 7.0 (5.0,10.0) , respectively, all P<0.01).The area under the curve(AUC) of receiver operating characteristic(ROC) curve for predicting 28 days death of APACHE Ⅱ,APACHE Ⅲ,SAPS Ⅱ,PAMI, TIMI-STEMI,TIMI-NSTEMI,and CADILLAC scoring systems were 0.820,0.797,0.785,0.667,0.657,0.711,and 0.821,respectively and cut-off value was 27.5,79.5,66.0,8.5,10.5,3.5,and 8.5, respectively and the sensitivity was 0.766,0.844,0.649,0.494,0.494,0.740,and 0.753, respectively and specificity was 0.816,0.755,0.837,0.204,0.796,0.571,and 0.755,respectively.The AUC of ROC of CADILLAC-plus scoring system was 0.885,cut-off value was 9.5, sensitivity was 0.896,and specificity was 0.735. The predicting efficacy of CADILLAC-plus scoring system was superior to other scoring systems. Conclusion: The 7 current scoring systems are all suitable for predicting theshort-term death in acute myocardial infarction patients complicating cardiogenic shock, and the predicting efficacy of the improved CADILLAC-plus score is superior to other scoring systems in this patient cohort.

[Detection of root cracks after root canal preparation using rotary NiTi systems by optical coherence tomography (OCT) scan]

OBJECTIVE

To evaluate the accuracy of optical coherence tomography (OCT) in detecting root cracks after root canal instrumentation using histological gold standard.

METHODS

Twenty complete extracted human mandibular incisors that were free of caries, calculus, and root treatment were chosen and accessed coronally with a diamond bur, then mounted in resin blocks with alginate impression material using simulated periodontal ligaments, and the apex was exposed 3 mm. The teeth were stored in water at room temperature. Then the teeth were then instrumented to the major apical foramen (AF) at #30/0.09 using ProTaper Universal rotary nickel titanium system (Dentsply Maillefer, Ballaigues, Switzerland), irrigation with 1% sodium hypochlorite (NaOCl) by using a 26-gauge needle followed after each instrument. The apical root was scanned with 360° of rotation by Swept-Source Optical Coherence Tomography (SS-OCT) (wavelength: 1 310 nm, scan rate: 20 kHz, axial resolution: 16 μm) with driving device (stepper motor and lifting platform). The reconstruction images of axial planes 1, 2 and 3 mm from the apex were examined and the root cracks were blindly diagnosed by two observers. The horizontal section was performed at 1, 2 and 3 mm from the apex using low speed disc saw (Leica SP1600, Wetzlar, Germany). The presence of cracks was noted under an optical stereomicroscope (ZOOM-630E) with a cold light source using as gold standard to evaluate the accuracy of OCT in detecting root cracks after root canal instrumentation.

RESULTS

After canals instrumentation with ProTaper Universal rotary nickel titanium system to #30/0.09, root cracks were detected in 9 of 20 teeth by histological examination. Crack lines were observed on 13 of 60 horizontal sections and cracks on 12 of the 13 sections were detected by OCT. No cracks were observed in the other 47 of the 60 horizontal sections,none of which was misdiagnosed by OCT. The overall accuracy rate for detection of root cracks with OCT was 0.983, the sensitivity was 0.923, the specificity was 1.000, the positive predictive value (PPV) was 1.000 and the negative predictive value (NPV) was 0.979.

CONCLUSION

OCT may be a promising nondestructive imaging method for diagnosing root canal cracks after canal instrumentation.

Methanol-Assisted Phthalimide Ring Opening: Concerted or Stepwise Mechanism?

The opening of the five-membered ring is the essential step for phthalimide and its derivatives to be used as the reactants in many chemical synthetic routes. Reportedly, such ring opening follows the concerted mechanism in methanol solvent, which, however, has an unreasonably high energy barrier (36.3 kcal mol^-1 at the M06-2X/6-311++G(d,p) level of theory). By density functional theory calculations, we report that this ring opening prefers the alternatively stepwise mechanism. The stepwise mechanism has a much lower energy barrier (21.0 kcal mol^-1 at the same level of theory) and thus is much more completive than the concerted one. The stepwise mechanism should be considered as the dominant mechanism responsible for the phthalimide ring opening when studying the kinetics of the relevant synthetic reactions in the future.

[Nano-sized bioactive glass enhances osteogenesis of critical bone defect in rabbits]

OBJECTIVE

To compare the osteogenic effects of a nano-sized 58S bioactive glass (nano-58S BG) and a traditional 45S5 bioactive glass(45S5 BG) in penetrating parietal critical bone defects.

METHODS

Critical bone defect with 9 mm diameter was created in the parietal bone of New Zealand rabbits. The bone defects were then filled with either nano-58S BG, or 45S5 BG, or nothing but the newly-formed blood clot as the blank control at random. For histological observation, specimens were gained 4 and 8 weeks after the surgery, sectioned and stained by HE. The amount of collagen type I was observed with Picric-Sirius Red staining through polarimetry. To observe the new bone formation with fluorescence under the laser confocal microscope, we injected fluorescent markers 14, 28, and 42 days after the surgery. The markers were tetracycline hydrochloride, alizarin red and calcin individually in chronological order. Image J software was used to quantify the bone regeneration.

RESULTS

HE staining showed that BG particulates were integrated with the surrounding tissue without any inflammatory cells infiltration 4 weeks after surgery. New bone regeneration was observed both from the border and in the center of the defects in both BG groups. No bone regeneration in defect center was observed in control group. At the end of 8 weeks, there was more bone regeneration in nano-58S group compared with 45S5 group and control group. The structure of the new bone in BG groups was hollow, which was similar to the natural normal parietal bone. No hollow structure was observed in the new bone of control group. Picric-sirius Red polarimetry showed that more amount of collagen type I was found in nano-58S group than in either 45S5 or control group. The fluorescent observation of the hard tissue slices at the end of 8 weeks showed statistically larger scope and faster new bone formation in nano-58S group with (29.4±4.48) μm thickness from 4-6 weeks and (35.3±3.74) μm from 6-8 weeks compared with 45S5 group [(13.43±3.44) μm and (17.64±4.13) μm] and control group [(5.88±2.92) μm and (6.07±3.02) μm, P<0.01].

CONCLUSION

Compared with the traditional 45S5 bioactive glass, 58S nano-sized bioactive glass showed better osteogenic effect in bone regeneration in parietal bones of rabbits.

[How to write and publish a scientific article in stomatology]

The general principles and key points in writing of a scientific article in stomatology were interpreted based on the national guideline and the author's personal experiences in the present article. Efforts should be made by the authors focusing on core information, refinement and description of their papers. In the second half of the article, the general process of paper review was introduced. The article also gave suggestions on how to response to the reviewers' questions. It is well recognized that a good scientific journal was created by good authors, good reviewers and good editors. The author proposed that efforts by above mentioned three parties should be gathered to make more valuable, delicately designed and well performed clinical research articles be published.

[Age-related coronary risk factors in Chinese patients with acute myocardial infarction]

Objective: To determine the age-related coronary risk factors in Chinese patients with acute myocardial infarction (AMI). Methods: Among 31 provinces, municipalities or autonomous districts in China, from January 1st 2013 to September 30th 2014, 24 394 consecutive AMI patients who were admitted to 107 hospitals were divided into five groups according to age. Cardiovascular risk factors of groupⅠ (<45 years, n=2 307), group Ⅱ (45-54 years, n=4 448), group Ⅲ (55-64 years, n=7 029), group Ⅳ (65-74 years, n=6 147) and group Ⅴ (≥75 years, n=4 463) patients were compared. Results: Among 24 394 AMI patients [with a mean age of (62.2±13.8) years, 18 162 males], 24.7% patients had three and more conventional modifiable cardiovascular risk factors. ST-elevation myocardial infarction (STEMI) was diagnosed in 18 209 (74.6%) patients. The ratios of female, hypertension and diabetes tended to increase with the increase of age. Young AMI patients were predisposed to smoking, overweight/obesity and hyperglycemia. Nearly 90% patients in group Ⅰ and group Ⅱ were male. The ratio of male patients (92.3% to 58.0%), overweight/obesity (63.9% to 37.4%), current smoking (68.7% to 19.8%), dyslipidemia (9.1% to 4.5%), family history of premature coronary artery disease (CAD) (6.2% to 1.2%) and eating greasy food (86.1% to 66.2%) decreased markedly from group Ⅰ to Ⅴ patients. Proportion of hypertension gradually increased from 34.3% in group Ⅰ patients to 57.9% in group Ⅴ patients. Diabetes was most common to group Ⅳ (65-74 years) patients. Conclusion: There were different risk factors for AMI patients in different age groups, and young AMI patients were predisposed to live an unhealthy lifestyle.

[Relationship between shift work and overweight/obesity in male steel workers]

Objective: To investigate the relationship between shift work and overweight/obesity in male steel workers. Methods: A questionnaire survey was conducted among the male steel workers selected during health examination in Tangshan Steel Company from March 2015 to March 2016. The relationship between shift work and overweight/obesity in the male steel workers were analyzed by using logistic regression model and restricted cubic splinemodel. Results: A total of 7 262 male steel workers were surveyed, the overall prevalence of overweight/obesitywas 64.5% (4 686/7 262), the overweight rate was 34.3% and the obesity rate was 30.2%, respectively. After adjusting for age, educational level and average family income level per month by multivariable logistic regression analysis, shift work was associated with overweight/obesity and obesity in the male steel workers. The OR was 1.19(95% CI: 1.05-1.35) and 1.15(95% CI: 1.00-1.32). Restricted cubic spline model analysis showed that the relationship between shift work years and overweight/obesity in the male steel workers was a nonlinear dose response one (nonlinear test χ²=7.43, P<0.05). Restricted cubic spline model analysis showed that the relationship between shift work years and obesity in the male steel workers was a nonlinear dose response one (nonlinear test χ²=10.48, P<0.05). Conclusion: Shift work was associated with overweight and obesity in the male steel workers, and shift work years and overweight/obesity had a nonlinear relationship.

Computational Study on the Mechanisms of Multiple Complexation of CO and Isonitrile Ligands to Boron

The recent experimental realization of compound Tripp-B(CO)₂ (denoted as 2a), where Tripp is 2,6-di(2,4,6-triisopropylphenyl)-phenyl), breaks through conventional knowledge that only transition metals can bind more than one CO to form multicarbonyl adducts. Compound 2a is stable in air but liberates CO under light. The B-CO bonds of 2a are considered to be similar to donor-acceptor bonds of transition metal complexes. To address the formation mechanism and chemical bonding of this novel type of boron compounds, we present a density functional theory study on the formation and photolysis of 2a and similar compounds. The results suggest that the formation of 2a is facile by three consecutive additions of CO to the terminal borylene metal complex, that is, the boron source of the synthesis. These CO additions can be practically accomplished via two different paths: CO direct addition and CO migration followed by addition. Such mechanisms can be excellently rationalized by the donor-acceptor bonding model of the terminal borylene complex, which in turn suggests that using donor-acceptor bonds for 2a is natural for understanding the mechanisms. Liberation of CO from 2a and its similar compounds has higher energy barriers at the ground states than that at the triplet states by 40 kcal/mol. These energy barriers explain the experimentally observed air stability and photolysis of these compounds. The results for the first time provide mechanistic insights for the unprecedented chemical processes; they allow evaluation of the applicability of donor-acceptor bonding in main-group compounds from the new perspective of chemical reactions.

Metal-like Boronic-Organic Frameworks: A Design and Computation

Because of the lack of strong π-interaction in their bonds connecting building units, most of the metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs) achieved so far are insulators or wide-bandgap semiconductors. The design of metal-like frameworks based on known chemical components is a challenge. This work reports that aryl borons can be linked together through isocyanides to form stable and easily accessible low-dimensional boronic-organic frameworks (BOFs). Particularly, the boron atoms in the BOFs behave like transition metals, forming the combined σ-donation and π-backdonation bonds instead of the usual electron-sharing bonds with the isocyanide linkers. This peculiar bonding endows BOFs with semimetal and narrow-bandgap semiconductor features, which are different from MOFs and COFs and may be found to be useful in future nanoelectronics. The results open a door to integrating the knowledge of the donor-acceptor chemistry in the main group into materials science.

[Influence of Coca-Cola on early erosion and surface microhardness of human enamel: an in situ study]

OBJECTIVE

Assessed the effect of single dose attack of Coca-Cola on early erosion and surface microhardness of permanent human enamel, in order to provide diet instructions on minimum amount and frequency of carbonated beverage consumption.

METHODS

Eighty enamel slabs were prepared out of 10 extracted human mandibular third molars, and distributed into 8 groups with randomized block design(n=10). Ten generally healthy volunteers with normal saliva secretion wore acrylic palatal appliances containing 2 enamel slabs, with formation of a salivary pellicle 2 h ahead. The volunteers were instructed to drink 100 ml fresh Coca-Cola within 20 s. And then the alterations of the enamel slabs were measured using a Vicker's microhardness tester at 1, 2, 4, 6, 8, 10, 20 and 30 min after the consumption of Coca-Cola. For each volunteer, the experiment was carried out in four days, 2 samples were examined each time. Data were analyzed using Kruskal-Wallis and Wilcoxon tests(α =0.05).

RESULTS

Significant decreases in surface microhardness(SMH)were observed in each time point(P<0.01). The percentages of surface microhardness changes on each exposure time were(12.2±3.9)%,(16.8±5.5)%,(16.7±5.6)%,(16.2±6.2)%,(16.6±9.0)%,(15.6±3.7)%,(13.8±4.8)% and(11.4±3.2)%, respectively. Significant differences were observed between G1 min and G2-8 min(P=0.029), G2-8 min and G30 min(P=0.008).

CONCLUSIONS

Single intake of 100 ml Coca-Cola could lead to significant decrease of enamel microhardness and initiate erosion of enamel surface. Enamel surface microhardness decreased to the lowest points at 2-8 min, and began to recover after 10 min. The enamel surface microhardness could not fully recovered to the baseline level in 30 min if no intervention was performed.

[Rheumatoid arthritis involving tibialis posterior tendon: study on the early diagnostic value of power Doppler ultrasonography and comparison with surgery]

Objective: To explore the value of power Doppler ultrasonography (PDUS) in the early diagnosis of tibialis posterior tendon injury induced by rheumatoid arthritis (RA). Method: From January 2014 to December 2015, a total of 48 cases (60 feet) of RA tendinopathy group were selected as the research subjects from Guanghua Hospital; 12 cases(20 feet) of non-RA tendinopathy group and 10 cases (20 feet) of healthy volunteers were selected as control group.The blood flow signals of pannus were observed by PDUS to determine whether the tendon was injured or the degree of the injury. The following indexes were compared and analyzed by Chi-square testing: (1)positive rate of blood flow signal; (2)grade of blood flow signal; (3)spatial distribution of blood flow signal: diffusibility or local. Results: Of 70 cases(100 feet) in the study, the positive blood flow signals were only in the RA(88.3%) and non-RA group(40.0%) .Grade Ⅲ in RA was 20.0%, while this was not observed in non-RA . Grade Ⅱ in RA and non-RA was 36.7% and 10.0% , respectively. There were significant differences in the positive rate and grades between RA and non-RA group (P<0.01). The spatial distribution of blood flow signal in RA was significantly different from that in non-RA. In RA, they can be detected in the whole tendon.However, they were mainly distributed around the scaphoid in non-RA. In this study, three patients with grade Ⅲwere treated with surgery. The intraoperative findings were consistent with the preoperative ultrasound results. Conclusions: PDUS can be used to detect the neovascular formation of tendon synovitis. It can detect the early tendon injury before the appearance of foot deformity induced by RA, which can guide clinical early intervention treatment and prevent the occurrence of deformity and other serious consequences.

[Effect of root canal sealers on biocompatibility of human periodontal ligament cells]

OBJECTIVE

To compare the effects of three root canal sealers with respect to time on biocompatibility of human periodontal ligament cells (hPDLCs).The sealers included zinc oxide and eugenol based sealers (ZOE), epoxy resin sealers (ERS) and silicone based sealers (SBS).

METHODS

hPDLCs were primarily cultured,with the method combining of tissue explant and enzymatic digestion. The cells were then exposed to different extract fluids: (1) ZOE extracted for 24 h group ;(2) ZOE extracted for 1 week group;(3)ZOE extracted for 2 weeks group;(4) ERS extracted after 24 h group; (5) ERS extracted after 1 week group; (6) ERS extracted after 2 weeks group; (7) SBS extracted after 24 h group; (8) SBS extracted after 1 week group; (9) SBS extracted after 2 weeks group; (10) Dulbecco modified Eagle's medium/F12 (DMEM/F12) as negative control group. Cell morphology was observed under an inverted microscope.Cell proliferation was measured by methyl-thiazol-diphenyltetrazolium (MTT) assay. ALP assay kit was used for measuring alkaline phosphatase (ALP) activity. Sealers of 2 weeks' setting time were then immersed in an osteogenic medium for examination of mineral nodules and calcium deposits.

RESULTS

Considering the relative growth rate(RGR),ZOE was severely to moderately cytotoxic(RGR:13.6%-39.9%), while ERS was slightly or not cytotoxic (RGR: 87.6%-95.3%).Only SBS did not show any cytotoxicity after setting (RGR: 91.8%-106.7%). The setting time influenced the cytotoxicity of ERS which decreased after 1 week. Considering the ALP activity,there was no difference between SBS group and control group (F=3.397,P=0.053). According to the results of calcium deposits, ZOE:D562 nm=0.180±0.050,ERS: D562 nm=2.968±0.201,SBS:D562 nm=3.623±0.039,Control:D562 nm=3.477±0.102,the ranking of ALP activity and calcium deposits was as follows: ZOE<ERS <SBS=Control.

CONCLUSION

The cytotoxicity of ZOE was the highest and persisted with time. The setting time had influence on the cytotoxicity of ERS. Only SBS did not show any cytotoxicity or inhibition of the mineral potential on hPDLCs, indicating which was more biocompatible than the others.

[Survey of medical care resources of acute myocardial infarction in different regions and levels of hospitals in China]

OBJECTIVE

To investigate the medical care resources of acute myocardial infarction (AMI) in Chinese hospitals of different regions and levels.

METHODS

We selected 115 hospitals in China, including 61 northern hospitals, 54 southern hospitals, 52 eastern hospitals, 26 central hospitals, 37 western hospitals, 79 tertiary hospitals, 36 secondary hospitals, 34 pro vincial-level hospitals, 46 prefectural-level hospitals and 35 county hospitals. From November 2012 to August 2013, we sent questionnaire to the cardiologists in each hospital, to collect related information.

RESULTS

(1) The number of AMI admitted each year of northern hospital was more than the number of southern hospital (220 (120, 400) cases vs. 220 (80, 350) cases, P=0.033), while number of coronary care unit (CCU), thrombolytic therapy, percutaneous coronary intervention (PCI), primary PCI and coronary artery bypass grafting (CABG) were similar (all P> 0.05). (2) The number of AMI admitted each year of eastern, central and western hospital was 295(150, 501) cases, 175(75, 300) cases and 170(50, 250) cases respectively(P=0.007), with no significant difference among them for setting CCU, carrying out thrombolytic therapy, PCI, primary PCI and CABG (all P>0.05). (3) The total number of the in-patient beds and AMI admitted each year of tertiary hospitals were significantly higher than that in the secondary hospitals(104(70, 152)vs. 47(30, 52), P<0.001) and (300(200, 460)cases vs.80(47, 135)cases, P<0.001) respectively. There was a significant difference between tertiary and secondary hospitals for the number of CCU (97.5% (77/79)and 75.0%(27/36)), PCI (98.7%(78/79)and 27.8%(10/36)), primary PCI (96.2%(76/79)and 22.2%(8/36)), CABG (81.0%(64/79)and 11.1%(4/36)), intra-aortic balloon pump (IABP) (91.1%(72/79) and 13.9%(5/36)) respectively (all P<0.001). (4) There were obvious differences among provincial-level, prefectural-level and country-level hospitals for the admitted AMI patient numbers annually which was 400(250, 600), 232(100, 380)and 80(50, 162)cases, CCU proportion which was 100 %(34/34), 95.7%(44/46) and 74.3%(26/35), thrombolytic therapy proportion which was 88.2%(30/34), 100%(46/46)and 91.4%(32/35), PCI proportion which was 100%(34/34), 89.1%(41/46)and 37.1%(13/35), primary PCI proportion which was 100%(34/34), 84.8%(39/46)and 31.4%(11/35), CABG proportion which was 97.1%(33/34), 67.4%(31/46) and 11.4%(4/35)respectively (P<0.01 or 0.05) .

CONCLUSIONS

Different regional hospitals have no significant difference in number of CCU and reperfusion therapies, while there is a big difference on medical care resources of AMI between different-level hospitals, which may affect the diagnosis and treatment effect of patients with AMI. Clinical Trail Registry: National Institutes of Health, NCT01874691.

Effect of tumor necrosis factor-induced protein 8 on T-cell-mediated immunity in mice after thermal injury

Tumor necrosis factor-induced protein 8(TNFAIP8), the first identified member of the TNFAIP8 family, shares considerable sequence homology with members of this family. It is expressed in a wide variety of human normal tissues, with relatively higher levels in lymphoid tissues and placenta. The present study was designed to examine the effect of TNFAIP8 on T-cell-mediated immunity secondary to burn injury. Sixty male mice were randomly divided into four groups as follows: sham burn group, burn group, burn with TNFAIP8-siRNA transfection group, and burn with negative control transfection group, and they were sacrificed at designated time points. CD4+ T cells were isolated using MACS microbeads. T-Cell proliferation was analyzed with MTT assay, and IL-2, soluble IL-2R, IL-4, interferon-γ (IFN-γ) were determined with enzyme-linked immunosorbent assay kits. It was found that CD4+ T lymphocyte proliferative activity was significantly down-regulated when TNFAIP8 gene was silenced by siRNA in mice at 24 h post burn. Down-regulation of TNFAIP8 can significantly decrease expression levels of IL-2 and soluble IL-2R at 24 h after thermal injury. These results demonstrated that TNFAIP8 appeared to be involved in the immune regulation of CD4+ T lymphocytes, and the decreased expression of TNFAIP8 could affect T lymphocyte functions after thermal injury.

Fullerenes and their derivatives as inhibitors of tumor necrosis factor-α with highly promoted affinities

Tumor necrosis factor-α (TNF-α) is a cell signalling protein involved in systemic inflammation in infectious and other malignant diseases. Physiologically, it plays an important role in regulating host defence, but its overexpression can lead to serious illnesses including cancer, autoimmune disease and inflammatory disease. Gadolinium-based metallofullerenols, e.g., Gd@C82(OH) x (x ≈ 22), are well known for their abundant biological activities with low toxicity experimentally and theoretically; however, their activity in direct TNF-α inhibition has not been explored. In this work, we investigated the inhibiting effects of four types of fullerene-based ligands: fullerenes, fullerenols, metallofullerenes, and metallofullerenols. We reported previously that fullerenes, metallofullerenes and their hydroxylated derivatives (fullerenols) can reside in the same pocket of the TNF-α dimer as that of SPD304-a known inhibitor of TNF-α [He et al. (2005) Science 310:1022, 18]. Ligand docking and binding free energy calculations suggest that, with a similar nonpolar interaction dominated binding pattern, the fullerene-based ligands, C60, C60(OH)12, Gd@C60, C82, C82(OH)12, Gd@C82, Gd@C82(OH)13 and Gd@C82(OH)21, have larger affinity than currently known inhibitors, and could be used to design novel inhibitors of TNF-α in the future. Graphical Abstract Fullerene-material/TNF-α.

[Comparison of periapical radiography and cone-beam computed tomography in endodontic treated teeth for assessment of periapical lesions]

OBJECTIVE

To compare the assessments of the presence or absence and the changes of post-treatment periapical lesions using periapical radiographs versus cone-beam computed tomography (CBCT).

METHODS

Imaging records were selected from a sample of 233 radiographic examinations (including periapical radiographs and CBCT) of patients with chronic apical periododontitis who received treatment and review in Department of Cariology and Endodontology of Peking University School of Stomatology. After testing the inter-observer and intra-observer agreement, two observers determined the presence or absence of a periapical lesion and classified the changes of lesions in 4 categories: absence, reduction or enlargement of lesion, or uncertain. The differences between CBCT and periapical radiographs in detecting the presence or absence and the changes of periapical lesions were compared using McNemar test and Fisher's exact test respectively.

RESULTS

In the study, 233 teeth were assessed with both periapical radiographs and CBCT images. Periapical lesions were detected in 178 teeth on CBCT scans and in 146 teeth on periapical radiographs. CBCT images revealed a significantly larger number of lesions than were revealed by periapical radiographs (P<0.01). There was disagreement on the changes of lesions between the two radiological technologies in 25% teeth, and the difference was statistically significant (P<0.01).

CONCLUSION

Significant differences were observed between periapical radiographs and CBCT in detection of post-treatment periapical lesions and assessment of the changes of periapical lesions.

[Age-related differences in the clinical symptoms and triggering factors among Chinese patients with acute myocardial infarction]

OBJECTIVE

To analyze the age-related differences in the clinical symptoms and triggering factors among Chinese patients with acute myocardial infarction.

METHODS

Acute myocardial infarction Patients (n=14 854) registered in the China Acute Myocardial Infarction Registry from January 2013 to March 2014 were included in this study. Patients were divided into 4 groups: <55 years old group (3 950 patients), 55-64 years old group (4 361 patients), 65-74 years old group ( 3 759 patients), and ≥75 years old group (2 784 patients). Demographic features, medical history, clinical presentation and triggering factors were obtained via electronic data capture system.

RESULTS

(1)Persistent chest pain and sweat were the major typical symptoms 66.4%(9 863/14 854) and 63.8%(9 471/14 854)) in the whole cohort. Prevalence of persistent chest pain among four groups were 73.8%(2 915/3 950), 69.2%(3 016/4 361), 63.6%(2 394/3 759) and 55.2%(1 538/2 784), and radiating pain among four groups were 36.2%(1 428/3 950), 34.1%(1 487/4 361), 30.9%(1 160/3 759)and 25.9%(722/2 784), and sweat among four groups were 70.0%(2 765/3 950), 66.5%(2 898/4 361), 61.8%%(2 323/3 759)and 53.3%(1 485/2 784), and there were statistical significance for all above symptoms among groups (all P<0.001). (2)triggering factors before acute myocardial infarction could be found in 19.4%(2 879/14 854) of the patients. Prevalence of existed triggering factors among four groups were 23.8%(941/3 950), 21.0%(914/4 361), 16.6%(625/3 759) and 14.3%(399/2 784, P<0.001). Recent excessive unhealthy lifestyles among four groups were 20.8%(196/3 950), 11.9%(109/4 361), 10.1%(63/3 759) and 9.0%(36/2 784) among the 4 groups (P<0.001).

CONCLUSIONS

Persistent chest pain and sweat are absent in nearly half of Chinese patients in ≥75 years old group. Triggering factors prior to acute myocardial infarction could be evidenced in about twenty percent patients, and which are more often in young patients. Clinical Trail Registry: National Institutes of Health，NCT018746.