[Clinical and prognostic analysis of accessory pathway-induced dilated cardiomyopathy after catheter ablation in children]

Objective: To investigate the clinical characteristics and prognostic factors after catheter ablation of accessory pathway (AP)-induced dilated cardiomyopathy (DCM) in children. Methods: Data were collected and analyzed on 147 consecutive pediatric patients (81males and 66 females), who hospitalized in our pediatric heart center between January 2009 and August 2018 and received catheter ablation for ventricular pre-excitation (right AP). Thirty-one children were diagnosed as AP-induced DCM and 116 children with normal cardiac function served as control. Data including clinical characteristics, electrocardiogram (ECG), echocardiography, electrophysiological examination (EPS), successful ablation and follow up were analyzed. Results: The median age at first examination was 3.07 (0.09, 5.83) years. The pre-hospital misdiagnosis rate was 87.1% (27/31). The incidence of the AP-induced DCM was 21.1% (31/147) and the rate of right anterior free wall accessory pathway (AP) was the highest (50.0%, 10/20). AP-induced DCM was more common in right free wall Aps (41.9%, 13/31) and right anterior free wall (32.3%, 10/31). 48.4% (15/31) cases had no supraventricular tachycardia (SVT). EPS showed that 29% (9/31) of the AP did not have retrograde conduction. The median follow-up time after successful catheter ablation was 8 (2, 36) months of AP-induced DCM group, LVDd was significantly decreased ((41.6±12.8)mm vs. (45.6±13.9)mm, P<0.01) and LVEF ((56.2±11.8)% vs. (40.8±12.5)%, P<0.01) was significantly increased after ablation. Cox regression analysis showed that LVEF was the predictor of the duration of cardiac function recovery (HR=1.08, 95%CI 1.01-1.15, P=0.03). Conclusions: Misdiagnosis rate is high for children with AP-induced DCM, leading to the delayed treatment. All of the AP-induced DCM occurred in right APs and right anterior free wall APs is the highest. Right free wall APs and right anterior free wall are most common in AP-induced DCM. Catheter ablation is a safe and effective treatment option for these patients. The lower the LVEF, the longer the cardiac function recovery.

A Linear Regression Predictor for Identifying N6-Methyladenosine Sites Using Frequent Gapped K-mer Pattern

N6-methyladenosine (m⁶A) is one of the most common and abundant modifications in RNA, which is related to many biological processes in humans. Abnormal RNA modifications are often associated with a series of diseases, including tumors, neurogenic diseases, and embryonic retardation. Therefore, identifying m⁶A sites is of paramount importance in the post-genomic age. Although many lab-based methods have been proposed to annotate m⁶A sites, they are time consuming and cost ineffective. In view of the drawbacks of the intrinsic methods in RNA sequence recognition, computational methods are suggested as a supplement to identify m⁶A sites. In this study, we develop a novel feature extraction algorithm based on the frequent gapped k-mer pattern (FGKP) and apply the linear regression to construct the prediction model. The new predictor is used to identify m⁶A sites in the Saccharomyces cerevisiae database. It has been shown by the 10-fold cross-validation that the performance is better than that of recent methods. Comparative results indicate that our model has great potential to become a useful and effective tool for genome analysis and gain more insights for locating m⁶A sites.

[Effects of miR-144 on proliferation, apoptosis and cisplatin resistance by targeting MYCN in pediatric neuroblastoma]

Objective: To investigate the effects and mechanisms of miR-144 on proliferation, apoptosis and cisplatin (DDP) resistance of neuroblastoma cells. Methods: Real-time fluorescence quantitative PCR (RT-qPCR) was used to detect the mRNA expressions of miR-144 and MYCN in neuroblastoma cell lines, including SH-SY5Y and SK-N-SH, and human umbilical vein endothelial cells HUVEC. The miR-negative control, miR-144 mimics, si-negative control, si-MYCN, miR-144 mimics and pcDNA, miR-144 mimics and pcDNA-MYCN co-transfected SH-SY5Y cells were described as miR-NC, miR-144, si-NC, si-MYCN, miR-144+ pcDNA and miR-144+ pcDNA-MYCN group, respectively. The half maximal inhibitory concentration (IC(50)) and cell proliferation were detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay. The protein expressions of MYCN, p21, cyclin D1, Bax, Bcl-2 were analyzed by western blot. Cell apoptosis was detected by flow cytometry. The cell fluorescence activity was detected by double luciferase reporter gene assay. Results: Compared with HUVEC cells, the expressions of miR-144 in neuroblastoma cells SH-SY5Y and SK-N-SH significantly decreased, while the mRNA and protein expression of MYCN significantly increased. The IC(50) of DDP was 9.16 μg/ml in SH-SY5Y cells. The absorbance value in 490nm (A(490) value) of miR-144 group was 0.30±0.03, significantly lower than 0.46±0.03 of miR-NC group. The cell apoptotic rate of miR-144 group was 26.94%±2.01%, significantly higher than 9.68%±0.52% of miR-NC group. The IC(50) value of DDP in miR-144 group was 2.95±0.26, significantly lower than 9.23±0.61 of miR-NC group. The expressions of p21, cyclin D1, Bax, Bcl-2 in miR-NC and miR-144 group were 2.67±0.19, 0.41±0.04, 2.12±0.21, 0.18±0.01 and 1.01±0.07, 1.00±0.06, 1.00±0.05, 1.00±0.06, respectively, with statistical significance (all P<0.05). Knockdown of MYCN showed the similar effects with those of miR-144 overexpression in SH-SYSY cells. MiR-144 significantly inhibited the fluorescence activity of ectopic MYCN expressing cells and negatively regulated the expression of MYCN. Overexpression of MYCN can reverse the effects of miR-144 on proliferation inhibition, apoptosis promotion and sensitization of SH-SY5Y cells to DDP. Conclusion: MiR-144 inhibits proliferation, promotes apoptosis and enhances the sensitivity of neuroblastoma cells to DDP through targeting MYCN, which provides a potential treatment for neuroblastoma.

A comparative study of the thermoelectric performance of graphene-like BX (X = P, As, Sb) monolayers

The electronic and phonon transport properties of graphene-like boron phosphide (BP), boron arsenide (BAs), and boron antimonide (BSb) monolayers are investigated using first-principles calculations combined with the Boltzmann theory. By considering both the phonon-phonon and electron-phonon scatterings, we demonstrate that the strong bond anharmonicity in the BAs and BSb monolayers can dramatically suppress the phonon relaxation time but hardly affect that of electron. As a consequence, both systems exhibit comparable power factors with that of the BP monolayer but much lower lattice thermal conductivities. Accordingly, a maximum ZT value above 3.0 can be realized in both BAs and BSb monolayers at optimized carrier concentration. Interestingly, very similar p - and n-type thermoelectric performance is observed in the BSb monolayer along the zigzag direction, which is of vital importance in the fabrication of thermoelectric modules with comparable efficiencies.

[PDCD4 enhances the inhibitory effect of As(2)O(3) on the growth and NF-κB signaling pathway in neuroblastoma cells]

Objective: To investigate the inhibitory effect of programmed cell death factor 4 (PDCD4) on arsenic trioxide (As(2)O(3))-induced cell growth and nuclear factor kappa B (NF-κB) signaling pathway in neuroblastoma. Methods: The PDCD4 overexpression vector was transfected into neuroblastoma cells and detected by fluorescence quantitative PCR and Western blot. As(2)O(3) was used to treat PDCD4 overexpressing neuroblastoma cells. MTT assay was used to measure the proliferation. Colony formation assay was used to determine the cell clone forming ability. Apoptosis was measured by flow cytometry. Western blot was used to detect the expression of NF-κB p65 and cleaved caspase-3 protein in cells. Results: The transfection of PDCD4 overexpression vector significantly increased the expression level of PDCD4 in neuroblastoma cells. The cell survival rates of the control group, PDCD4 group, As(2)O(3) group and As(2)O(3)+ PDCD4 group were 100%, (72.14±5.20)%, (62.58±3.14)% and (40.87±2.47)%, respectively. The colony formation rates in these four groups were (91.25±8.36)%, (65.32±7.14)%, (57.23±5.28)% and (37.14±3.64)%, respectively. In addition, the cell apoptotic rates of these four groups were (3.57±0.24)%, (28.64±3.20)%, (36.41±4.58)% and (49.65±5.27)%, respectively. Therefore, overexpression of PDCD4 in the absence or presence of As(2)O(3) inhibited cell proliferation and clone formation ability, while promoted apoptosis. Furthermore, the expression levels of cleaved caspase-3 in the control group, PDCD4 group, As(2)O(3) group and As(2)O(3)+ PDCD4 group were 0.21±0.03, 0.30±0.02, 0.43±0.05 and 0.57±0.06, respectively. And the expression levels of NF-κB p65 protein were 0.68±0.04, 0.52±0.03, 0.43±0.04, and 0.32±0.02, respectively. Compared with the control group, the expression levels of NF-κB p65 protein in PDCD4 group, As(2)O(3) group and As(2)O(3)+ PDCD4 group were significantly decreased (P<0.05), whereas the expression level of cleaved Caspase-3 protein was significantly increased (P<0.05). The changes in As(2)O(3)+ PDCD4 group were more significant than those in PDCD4 group and As(2)O(3) groups (both P<0.05). Conclusion: PDCD4 enhances the inhibitory effect of As(2)O(3) on the growth and NF-κB signaling pathway in neuroblastoma cells.

[Clinical analysis of right atrial appendage aneurysms complicated by atrial tachyarrhythmias in three children]

Objective: To investigate the clinical features and results of treatment for right atrial appendage aneurysms complicated by atrial tachyarrhythmias in children. Methods: This retrospective study included three children with right atrial appendage aneurysm complicated by atrial tachyarrhythmias (aged 1.0 to 5.3 years, weight 10 to 17.1 kg) who were hospitalized at the Pediatric Cardiology Department (Heart Center) of the First Hospital of Tsinghua University (Beijing Huaxin Hospital) during the period from January 2016 through April 2018. The patients' clinical features, the results of electrocardiogram (ECG) and echocardiography, the effects of therapeutic interventions (antiarrhythmics, radiofrequency ablation, and surgical resection of right atrial appendage aneurysm) and the results of pathological assessment were analyzed. Results: Three cases of right atrial appendage aneurysm were diagnosed at 36 weeks of gestational age, 1 month and 4 months after birth respectively. In two cases, ECG showed alternating episodes of atrial tachyarrhythmias including atrial tachycardia, atrial flutter, and atrial fibrillation, and echocardiography showed aneurysmal dilatation of right atrial appendage. These two cases underwent right atrial appendage aneurysm resection. In the remaining one case of atrial tachycardia, echocardiography did not visualize important lesions in the right atrium, thus the intracardiac electrophysiologic study and radiofrequency ablation were performed; and focal atrial tachycardia originating from the apex of right atrial appendage was mapped but failed to be ablated; consequently, the patient received the right atrial appendage resection, in which the right atrial appendage aneurysm was found. Preoperative multiple antiarrhythmics showed only modest or no efficacy for all the three cases. The atrial tachyarrhythmias disappeared in all the three cases after right atrial appendage aneurysm resection. Postoperative atrial tachycardias associated with new foci of impulse formation developed in two cases. These two patients reverted to normal sinus rhythm and remained in this rhythm by using antiarrhythmics. Pathological assessment showed cystic dilation of parts of atrial cavity, fibrosis of cyst wall, generalized fibrosis of atrial myocardium combined with myocardial atrophy and cystic dilation, as well as uneven myocardial thickness with generalized myocardial interstitial fibrosis. Conclusions: For patients with congenital right atrial appendage aneurysm, atrial tachyarrhythmias might develop during fetal stage or early postpartum period. Reliance on echocardiography might often lead to the missed diagnosis. These patients with atrial tachyarrhythmias responded poorly to antiarrhythmics. Radiofrequency ablation might be associated with a high risk and limited efficacy. Surgical resection of right atrial appendage aneurysm showed satisfactory results and should be highly recommended.

Placental weight and size in relation to fetal growth restriction: a case-control study

OBJECTIVE

Reductions in placental weight and size have been associated with reduced fetal growth. However, few studies have examined the association of placental weight and size with the risk of fetal growth restriction (FGR).

METHODS

We enrolled 121 mother-newborn pairs, including 54 FGR cases and 67 healthy controls, from our previous case-control study. The weight, surface area, and thickness of the placenta were measured by medical professionals.

RESULTS

Reduced placental weight and surface area were found to be associated with decreased birth weight. A 10-unit decrement in placental weight (g) and surface area (cm²) was associated with 33.9 (β = 33.9, 95% CI, 22.1-45.7) and 24.3 (β = 24.3, 95% CI, 11.2-37.5) g decrease in birth weight, respectively. Those associations varied by infant gender and the magnitudes of effect were larger among male fetuses. Moreover, reduced placental weight and surface area were associated with increased odds of FGR. A 10-unit decrease in placental weight and surface area were associated with 21% (OR = 1.21, 95% CI, 1.08-1.44) and 19% (OR = 1.19, 95% CI, 1.06-1.41) increase in the odds of FGR.

CONCLUSIONS

Our results suggest that fetuses with lower placental weight and smaller surface area are at higher risk of developing FGR.

[Clinical characteristics and treatment of congenital long QT syndrome in 58 children]

Objective: To assess the clinical characteristics, pathogenic genes and therapeutic effects of congenital long QT syndrome (LQTS) in children. Methods: A retrospective analysis included 58 LQTS children (37 boys, 21 girls; age of diagnosis (8.0±4.1) years, range 0.1 to 16.0 years) at Division of Pediatric Cardiology, First Hospital of Tsinghua University from August 2013 to November 2017. Each patient was evaluated with a detailed medical history, 12-lead resting electrocardiogram, Doppler echocardiography, and molecular genetic analysis. Results: Forty-eight of the children (83%) had a delay to diagnosis (0.7 (0.1, 2.0)years) and initially received a misdiagnosis. QT prolongation of unknown origin was found in 10 cases (17%), complex arrhythmic conditions in 27 cases (47%), myocarditis in 3 cases (5%), syncope of unknown origin in 3 cases (5%), epilepsy in 2 cases (3%), myocardial infarction in 1 case (2%), cardiomyopathy in 1 case (2%), and vasovagal syncope in 1 case (2%). Nine children presented with the positive family history of LQTS and three children had congenital nervous deafness. Twenty-one (36%) children presented with recurrent syncope, and 14 cases of whom had symptoms during physical activity and/or emotional stress. The common arrhythmias were ventricular arrhythmia (26 cases), sinus node dysfunction (18 cases), atrioventricular block (AVB) (12 cases), and atrial arrhythmia (6 cases). LQTS-associated pathologic or possibly pathologic mutations were found in 41 children (71%). Thirty-three children (57%) were treated with propranolol (22 cases), permanent pacemaker (PM) combined with propranolol (5 cases), PM (4 cases), and implantable cardioverter defibrillator (ICD) combined with propranolol (2 cases). Eighteen children (55%) were asymptomatic, thirteen children (39%) reported infrequent syncope, and one case (2%) died. Conclusions: LQTS in children is potentially malignant and present as phenotypic diversity and complex arrhythmias. LQTS-related pathogenic or possibly pathogenic mutations are identified in most of the children. Beta-blockers therapy is effective in reducing the risk of malignant cardiac events. Some children with LQTS should receive PM or ICD therapy.

Cerebral Nocardiosis: A Rare Cause of Hemiplegia in the Acute Medicine Unit

Nocardiosis, a rare infection occurring mostly in immunosuppressed patients can present with neurological complications including cerebral abscess formation, and is associated with high morbidity and mortality. We describe the case of a 54-year-old immunocompetent man with cerebral nocardiosis, who presented with sudden onset hemiparesis in an acute medicine unit. He required three craniotomies with excision, following failure to respond to antimicrobial therapy, with subsequent clinical improvement and radiological resolution of multiple cerebral abscesses. Challenges in diagnosis and management of hemiparesis in the acute medical unit are discussed. Successful management of cerebral nocardiosis require early communication with a neurosurgical unit, neuropathology and microbiology services to optimise management with targeted antimicrobial therapy.

[Increased receptor activator of nuclear factor kappa B ligand expressed on B10 cells in rheumatoid arthritis]

OBJECTIVE

To detect receptor activator of nuclear factor kappa B ligand (RANKL) expressed on B10 cells in rheumatoid arthritis (RA) and to evaluate the correlation between RANKL-producing B10 cells in RA and clinical features and laboratory parameters, trying to reveal the possible role of B10 cells in the pathogenesis of RA and the potential mechanism of impaired immunosuppressive capacities.

METHODS

25 RA patients and 20 healthy volunteers were enrolled. These RA patients did not received treatment with glucocorticoids, disease-modifying anti-rheumatic drug and biologics during the recent half of a year. The levels of RANKL-producing B10 cells were measured by flow cytometry (FCM) and polymerase chain reaction (PCR). The correlation between the frequencies of RANKL-producing B10 cells in RA and clinical data, laboratory parameters were analyzed. The role of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) in inducing RANKL expression in B10 cells was evaluated by in vitro stimulation assay. Independent samples t test, Pearson and Spearman correlation were used for statistical analysis.

RESULTS

B10 cells were capable of producing RANKL at a low level in health controls. The frequencies of RANKL-producing B10 cells were markedly higher in RA patients than in health controls (3.65%±1.59% vs. 2.25%±0.68%, P<0.01). The frequencies of these cells correlated positively with RA tender joint counts, swollen joint counts and disease activity score in 28 joints (DAS28) (r=0.479, P=0.035; r=0.519, P=0.008; r=0.526, P=0.019). However, no correlation was found between these cells and RA patient age, disease duration, or the levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF) and anti-citrullinated peptide antibody (ACPA). After in vitro stimulation by TNF-α, but not IL-1β, B10 cells isolated from healthy donors demonstrated fundamentally upregulated expression of RANKL.

CONCLUSION

Our studies showed the frequencies of RANKL-producing B10 cells were markedly higher in RA patients, and their frequencies were positively correlated with RA tender joint counts, swollen joint counts and DAS28. These findings suggested that B10 cells might be involved in RA bone destruction.

[3D electronic anatomy mapping guided radiofrequency catheter ablation in 95 children with atrioventricular nodal reentrant tachycardia]

Objective: To investigate the clinical features and evaluate the efficacy of radiofrequency catheter ablation (RFCA) guided by 3D electronic-anatomy mapping system (CARTO3 System) in children with atrioventricular nodal reentrant tachycardia (AVNRT). Methods: This was a retrospective case-controlled study. Data were collected from 95 children with AVNRT who underwent RFCA using CARTO3 System in the first hospital of Tsinghua University from January 2014 to December 2017. The onset age, characteristic of electrophysiology and anatomy feature of Koch triangle were analyzed. The efficacy and safety of ablation and X-ray fluoroscopy were compared with control 135 children with AVNRT who underwent RFCA without using CARTO3 System. The t test or the chi-square test was used for group comparison. Linear regression equation was established for correlation analysis. Results: The onset age of the 95 children (male 55, female 40; the average age (8.0±3.6) years) with AVNRT was (0.2-17.0) years and 23(24.2%) children were less than 3 years old. Electrophysiologic study showed that 84.2% (80 cases) was AVNRT-slow fast (SF), 11.6% (11 cases) AVNRT-slowslow and 4.2%(4 cases) AVNRT-fast slow. The phenomena of atrio-Hisian(AH) jump occurred in 65.3% and the interval of AH jump was (73.0±10.6) ms. The height of Koch triangle (CSo-His) was (22.3±5.8) mm and related with the weight of children (Y=0.171X+ 16.660, r(2)=0.224, P<0.001).The distance between the successful ablation target and the lowest point of His zone (ABL-His) was (11.7±2.6) mm. And there was no relation with the body weight(Y=-0.005X + 11.650, r(2)=0.001, P=0.780) and CSo-His (Y=0.072X+9.914, r(2)=0.030, P=0.171). The acute success rate was 97.9% (93/95) and recurrent rate was 5.4% (5/93) during follow-up. No obvious complication was reported. Compared with control group, the fluoroscopy time ((3.3±2.5) vs. (10.7±5.8) min, t=13.190, P<0.05), radiation dose ((5.4±4.9) vs. (15.5±6.3) mGy, t=13.660, P<0.05), and dose area product (514±445) vs. (2 478±415) mGy·cm(2), t=33.850, P<0.05) were decreased significantly. Conclusions: AVNRT-SF was the most common type of AVNRT. AVNRT incidence in infant and toddlers is lower than that in elder children. CSo-His is correlated with the body weight. ABL-His is relatively fixed. There is no correlation between ABL-His and the body weight and also no correlation between ABL-His and CSo-His. RFCA of AVNRT in children using the CARTO3 system is safe, effective and minimizes X-ray fluoroscopy.

[Feasibility of amplicon-based targeted next-generation sequencing of colorectal cancer in endoscopic biopsies]

Objective: To investigate whether small endoscopic biopsies of colorectal cancer were sufficient for quality and accurate mutational analysis by amplicon-based next-generation sequencing (NGS). Methods: By using an amplicon-based targeted NGS panel for mutational detection on Illumina Miseq platform, a total of 109 formalin-fixed and paraffin-embedded (FFPE) endoscopic biopsies of colorectal cancer were retrospectively selected, based on specific histopathologic criteria, from January 2012 to June 2016 at West China Hospital of Sichuan University and Peking University Third Hospital. Twelve of these biopsies had corresponding FFPE surgical resection specimens. Quality control parameters of NGS testing were analyzed and NGS results were confirmed by other methods. Mutation calls of the 12 paired endoscopic biopsies and surgical resections were compared. Results: Of the endoscopic biopsy specimens, 97.2% (106/109) had sufficient DNA and qualified sequencing library. NGS generated excellent sequencing data, with a median of 848× for median read depth and 95.7% for uniformity. The success rate of NGS was 95.4% (104/109). Conventional methods confirmed the results of NGS for KRAS and BRAF, and the concordance rate was 100.0%. The clinically actionable mutations detected in the 12 paired endoscopic biopsies and surgical resections were concordant. Conclusion: FFPE endoscopic biopsies of colorectal cancer is suitable for targeted NGS, providing quality sequencing data and accurate mutational information to guide targeted therapy.

[Characteristics of pulmonary vascular remodeling in rat model of pulmonary hypertension in left heart disease]

Objective: To investigate pulmonary vascular remodeling in rat model of pulmonary hypertension in left heart disease (PH-LHD). Methods: A total of 66 male minor Sprague-Dawley (SD) rats were randomly divided into control group (n=6), sham operation group (n=6) and model group (n=54). The rats in the control group entered the experimental procedure immediately without any treatment, and the rats in the sham operation group entered the experimental procedure 64 days after sham operation, and the rats in model group entered the experimental procedure (6 rats each) on day 1, day 3, day 5, day 8, day 15, day 22, day 36, day 50 and day 64 respectively after supracoronary aortic banding successfully. The lung tissue was fixed and cut and made into pathological sections to observe the characteristics of pulmonary vascular remodeling. Results: Medial thickening was mainly observed in pulmonary arterioles with diameter <100 μm [(11.17±1.03)%]. Additionally, medial thickening was seen in pulmonary arterioles with diameter 50-100 μm and 20-50 μm from day 15 [(12.73±1.15)%] and day 50 [(14.53±1.53)%], respectively. Medial muscularize of pulmonary arterioles were mainly observed in arterioles with diameter 20-50 μm, and deteriorated with time. Reduced pulmonary arteriole lumen size were observed with diameter 20-50 μm since day 50 (P<0.05). Conclusion: Pulmonary arteries with diameter >100 μm have little effect on the reconstruction of pulmonary vessels in PH-LHD rat model. However, arterioles with diameter 20-50 μm and 50-100 μm are the most important vessels involved in the formation of pulmonary hypertension, especially 20-50 μm.

[Changes in the composition of intestinal microbiota in mice with acute liver failure induced by D-galactosamine]

Objective: To investigate the changes in the composition of intestinal microbiota in mice with acute liver failure and identify characteristic bacteria, and to provide a basis for the diagnosis and treatment of acute liver failure with intestinal microbiota disorders. Methods: A total of 30 specific pathogen-free male BALB/c mice were used in this study, including 25 mice in the model group and 5 mice in the control group. An acute liver failure model was induced by D-galactosamine. Microbial DNA was extracted from intestinal contents in different segments of the lower digestive tract (ileum and colon) and feces and then were amplified using PCR. The regions of 16S V3-V4 were subjected to high-throughput sequencing, followed by bioinformatics analyses, including OTU hierarchical clustering, species annotation, alpha-diversity analysis, and LEfSe (LDA Effect Size) analysis. Comparison of continuous data was made using t-test, while comparison of categorical data was made using χ2 test. Results: A total of 10 mice survived in the two groups, with 80% mortality rate in the model group. The alpha-diversity analysis revealed increased bacterial diversity and abundance in the ileum, increased bacterial diversity and reduced bacterial abundance in the colon, and reduced bacterial diversity and insignificantly changed bacterial abundance in feces in the model group compared with the control group. Based on the optimized classification level, significantly reduced abundance of Clostridiaceae (44.95% ± 19.28% vs 7.51% ± 16.57%, P = 0.011) in the ileum, whereas significantly increased abundance of Rikenellaceae (1.08% ± 1.01% vs 4.18% ± 2.39%, P = 0.028), S24-7 (4.75% ± 4.87% vs 22.77% ± 13.05%, P = 0.020), and F16 (0.24% ± 0.28% vs 2.18% ± 1.61%, P = 0.029) in the colon were found in model group compared with the control group. The LEfSe analysis demonstrated that there were significant differences in Staphylococcaceae and S24-7 between the two groups, and S24-7 could be defined as the characteristic bacteria. Conclusion: Intestinal microbiota disorders, especially the excessive growth of microbes in the ileum, are observed in mice with acute liver failure. Moreover, acute liver failure may be closely associated with the excessive growth of S24-7.

Fluid Restriction for Treatment of “Fluid Creep” after Acute Burn Resuscitation

Objective

Fluid creep in patients recovering from acute burns still exists, despite the use of a more treatment conservative approach. Most of our severe burn patients develop fluid overload and body weight increase after acute fluid resuscitation. How to quickly return patients to their pre-injury body weight is an important issue.

Methods

Right after acute fluid resuscitation, we applied a “total fluid requirement” volume (usually 1/2 to 2/3 of initial 24 hour volume) and strictly monitored patients' hourly urine (between 0.5-1 ml/kg/hr). Patients' responses (body weight, enteric feeding amount, pulmonary condition, etc.) were also closely monitored and frequent adjustments of fluid volume administration were performed simultaneously.

Results

Most patients regained their pre-injury body weight within 2-3 weeks. Enteric feeding also improved markedly. No patients had severe oedema-related complications.

Conclusions

Stricter fluid administration after acute burn fluid resuscitation is advised for allowing patients to reduce body weight to their pre-injury weight or at least close to it. We use pre-injury body weight, enteric feeding and urine output as our guides. (Hong Kong j.emerg.med. 2014;21:222-229)

[Clinical challenges in the management of catecholaminergic polymorphic ventricular tachycardia in children]

Objective: Catecholaminergic polymorphic ventricular tachycardia (CPVT) accounts for up to 10%-15% sudden cardiac death (SCD) in the children and young population. This study aimed to assess the current situation and challenges in CPVT clinical diagnosis. Method: A retrospective review included 11 children (7 male patients) at the First Hospital of Tsinghua University clinically diagnosed with CPVT from June 2014 to July 2017. Each patient was evaluated with detailed history, physical examination, resting 12-lead electrocardiogram(ECG), 24-h Holter, exercise stress test, Doppler echocardiography and genetic test. Result: During physical activity and/or emotional stress, ten children presented with recurrent syncope and one child presented with palpitation and chest distress. The mean age of symptom onset was 8.4 (4.0-13.7) years with a delayed diagnosis of 2.4 (0.04-5.00) years. Two children had a familial history of syncope or sudden death. Nine children were initially misdiagnosed as complex arrhythmic conditions (n=4), syncope of unknown origin (n=3), and drug-resistant epilepsy (n=2) treated with antiepileptic medication for several years. Bidirectional VT and (or) polymorphic VT were detected using Holter recording or exercise test ECG in all patients. Genetic test revealed CPVT-associated pathologic or possible pathologic mutations in nine patients. All patients were treated with beta-blockers. Six patients were asymptomatic, four patients reported infrequent syncope, and one sudden death occurred during a mean follow-up of 0.97 years. Conclusion: CPVT mainly occurs in children and adolescents with recurrent syncope during physical activities and/or emotional stress. Early diagnosis of CPVT remains challenging due to delayed diagnosis or misdiagnosis. Detailed clinical history and exercise stress test improve the early diagnosis and intervention for CPVT patients.

[Relationship of symptoms with sleep-stage abnormalities in obstructive sleep apnea-hypopnea syndrome]

Objective:To study the relationship between symptoms and sleep staging in OSAHS patients.Method:A cross-sectional study. Adult subjects who attended a sleep laboratory for diagnostic polysomnography for a period of 1 month were recruited consecutively.OSAHS was diagnosed using American Academy of Sleep Medicine criteria.Subjects filled a questionnaire for symptoms prior to polysomnography.Result:Thirty subjects, of whom 83.3% were obese, met diagnostic criteria, with males constituting 46.7% and females constituting 53%.Mean age was (53.40±11.60) years.Sleep architecture comprised N1 (19.50±19.00)%, N2 (53.93±13.39)%,N3 (3.90±19.50)%, and rapid eye movement (8.92±6.21)%.Excessive fatigue or sleepiness, waking up tired, falling asleep during the day, trouble paying attention, snoring and insomnia were significantly related to decreased N3 sleep.Conclusion:Most of the symptoms in OSAHS in adults are related to decreased stage N3 sleep.If confirmed by larger controlled studies, correcting N3 sleep deficiency by pharmacotherapy may become an important adjunct to CPAP/BIPAP therapy to alleviate symptoms.

[Myeloid-derived suppressor cells promoted autologous B cell proliferation in rheumatoid arthritis]

OBJECTIVE

To investigate the effect of myeloid-derived suppressor cells (MDSC) on pro-liferation of B lymphocytes in rheumatoid arthritis (RA) patients.

METHODS

The peripheral blood specimens were collected from 15 healthy adults and 38 RA patients who were divided into high disease activity group, medium activity group and low activity group according to their 28-joint disease activity score (DAS28). And the frequencies of MDSC were determined by flow cytometry. Then, B cells and MDSC were isolated by flow cytometry, respectively. B cells were labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE) and then were co-cultured with MDSC in the presence of 3 mg/L anti-CD40 antibody and 10 mg/L CpG, for 3 days. Flow cytometry was performed to investigate the proliferation of B cells.

RESULTS

MDSC expanded markedly in high disease activity patients (7.13% ±2.17%) compared with medium (5.35%±1.36%) and low disease activity patients (4.72%±1.08%) or healthy controls (4.79%±1.02%) (P<0.05), and there were no statistical differences between healthy controls, medium and low disease activity RA (P>0.05). Moreover, the frequencies of MDSC were positively correlated with the DAS28 (P<0.05). After co-culture, MDSC significantly promoted B cell proliferation (P<0.01).

CONCLUSION

Our studies showed that MDSC expanded obviously in high disease activity RA patients, and their frequencies were positively correlated with the disease activities. Furthermore, MDSC could promote autologous B cell proliferation remarkably in vitro. These findings suggest that MDSC might be involved in RA pathogenesis through regulating B cell functions.

[Increased serum C-C chemokine ligand 19 levels correlated with B cell abnormalities in systemic lupus erythematosus]

OBJECTIVE

To detect the levels of serum C-C chemokine ligand 19 (CCL19) in patients with systemic lupus erythematosus (SLE) and to evaluate the correlation between CCL19 expression and clinical features and laboratory parameters, trying to reveal the possible role of CCL19 in the pathogenesis of systemic lupus erythematosus.

METHODS

The levels of serum CCL19 were measured by enzyme linked immunosorbent assay (ELISA) in 90 patients with SLE and 30 healthy controls. These SLE patients included 75 patients who received treatment with glucocorticoids and disease-modifying anti-rheumatic drug (DMARD) and 15 patients without therapy. The frequencies of peripheral blood B cells and the B cell subsets were assessed in the patients with SLE by flow cytometry. The correlation between the clinical data, laboratory parameters, B cell subset frequencies and serum CCL19 levels were analyzed. Indepen-dent samples t test, paired t test, Pearson and Spearman correlation were used for statistical analyses.

RESULTS

The levels of CCL19 were markedly higher in the SLE patients without therapy and the patients with therapy than in the health controls[(596.25±409.19) ng/L and (422.90±395.84) ng/L vs. (157.79±125.23) ng/L, all P<0.001]. Serum CCL19 levels in the SLE patients without therapy were higher than the SLE patients who accepted glucocorticoids and DMARD treatment (P<0.05). The levels of serum CCL19 were positively correlated with anti-double stranded deoxyribonucleic acid (dsDNA), anti-nucleosome antibody (AnuA), IgA, IgG and IgM (r=0.38, P=0.007; r=0.332, P=0.029; r=0.519, P=0.007; r=0.461, P=0.018, respectively). Serum CCL19 levels in the SLE patients with photosensitivity, arthritis and secondary Sjögren's syndrome were higher than the SLE patients without photosensitivity, arthritis and secondary Sjögren's syndrome, respectively [(562.25±399.12) ng/L, (565.6±435.24) ng/L and (694.9±531.02) ng/L vs. (394.7±281.42) ng/L, (385.90±325.33) ng/L and (424.8±305.46) ng/L, all P<0.05]. The levels of serum CCL19 were positively correlated with the percentage of CD27-B cells and CD27-IgD-double-negative memory B cells (r=0.519, P=0.007; r=0.461, P=0.018, respectively). However, the levels of serum CCL19 were negatively correlated with the percentage of CD27⁺ memory B cells and CD27⁺IgD^- switched memory B cells (r=-0.433, P=0.027; r=-0.616, P=0.001, respectively).

CONCLUSION

The increased serum CCL19 levels in SLE patients were associated with the production of autoantibodies, and CCL19 might be involved in the pathogenesis of SLE by disturbing the homeostasis of B cell subsets.

[Multicenter investigation of the correlation between supraventricular tachycardia and tachycardia-induced cardiomyopathy in children]

Objective: This study aimed to investigate the correlation between supraventricular tachycardia (SVT) and tachycardia-induced cardiomyopathy(TIC) in children and assess the risk factors for the development of TIC. Method: One hundred and eighty-three patients were recruited in four hospitals of Beijing diagnosed as SVT were divided into two groups depending on whether or not complicated with TIC. The age, gender, tachycardia type, ventricular rate during tachycardia, frequency of tachycardia episodes and duration of tachycardia were compared between the two groups and risk factors associated with TIC were analyzed. Statistical analyses were performed using t test, Mann-Whitney U and χ(2) test. Result: Totally 183 patients were included in this study (paroxysmal supraventricular tachycardia, PSVT, n=149; atrial tachycardia, AT, n=34). The incidence of TIC was 13.1%. There was significant difference regarding the incidence of TIC between children with AT and children with PSVT (26.5% vs. 10.1%, χ(2)=6.537, P=0.011). The percentage of AT in patients with TIC was significantly higher than patients without TIC (37.5% vs. 15.7%, χ(2)=6.537, P=0.011). Patients with TIC had a higher frequency of tachycardia episodes(2.5(1.0-4.8) beats/year vs 4.0(1.0-10.0) beats/year, Z=-2.223, P=0.026)and longer duration of tachycardia(11.0(1.1-36.0) h vs 2.5(1.0-12.0) h, Z=-2.154, P=0.031)compared with patients without TIC. Multivariate predictors of TIC was longer duration of tachycardia (OR=2.041, P=0.028). Conclusion: TIC occurs in 13.1% of children with SVT. The incidence of TIC in children with AT is higher than in children with PSVT. Risk factor for the development of TIC is longer duration of tachycardia.

Circulating periostin levels increase in association with bone density loss and healing progression during the early phase of hip fracture in Chinese older women

The present study shows that hip fracture women had higher serum periostin (sPostn) levels. The elevation of sPostn is associated with bone density loss, yet fracture itself may even increase sPostn levels during early healing phase.

INTRODUCTION

The study aims to quantify the associations of sPostn levels with bone density loss and the possible effect on the fracture healing.

METHODS

This study enrolled 261 older women with osteoporotic hip fracture and 106 age-matched women without fracture serving as controls. Clinical features, bone mineral density (BMD), and bone turnover markers including sPostn level were measured after fracture within 2 days. Follow-up sPostn levels during 1 year after 2 days were available for 128 patients.

RESULTS

Initial levels of sPostn after fracture were significantly higher in patients than controls. sPostn was correlated with BMD of femoral neck (r = -0.529, P < 0.001), β-isomerized C-terminal crosslinking of type I collagen (β-CTX) (r = 0.403, P = 0.008), and N-terminal procollagen of type I collagen (PINP) (r = 0.236, P = 0.042) in the entire cohort. After multivariate analysis, sPostn remained as an independent risk factor for femoral neck BMD, which explained 19.1% of the variance in BMD. sPostn sampled within 7 days after fracture were acutely increasing from day 2 and then decreased and maintained at slightly high levels at 360 days. The percentage changes of sPostn positively correlated with the variation in β-CTX (r = 0.396, P = 0.002) and PINP (r = 0.180, P = 0.033) at day 7 after fracture.

CONCLUSIONS

High sPostn levels were an independent predictor of femoral neck BMD in older women presenting with an acute hip fracture. Increased sPostn levels during early healing phase may imply that Postn play a role in bone repair.

Thermal conductivities of phosphorene allotropes from first-principles calculations: a comparative study

Phosphorene has attracted tremendous interest recently due to its intriguing electronic properties. However, the thermal transport properties of phosphorene, especially for its allotropes, are still not well-understood. In this work, we calculate the thermal conductivities of five phosphorene allotropes (α-, β-, γ-, δ- and ζ-phase) by using phonon Boltzmann transport theory combined with first-principles calculations. It is found that the α-phosphorene exhibits considerable anisotropic thermal transport, while it is less obvious in the other four phosphorene allotropes. The highest thermal conductivity is found in the β-phosphorene, followed by the δ-, γ- and ζ-phase. The much lower thermal conductivity of the ζ-phase can be attributed to its relatively complex atomic configuration. It is expected that the rich thermal transport properties of phosphorene allotropes can have potential applications in the thermoelectrics and thermal management.

[Epidemiological characteristics of HBeAg reversion in chronic hepatitis B patients with HBeAg seroconversion in Jiangsu province, 2012-2014]

Objective: To understand characteristics and influencing factors of reversion of HBeAg in chronic hepatitis B patients with HBeAg sero-conversion, and provide epidemiological evidence for the regular management of chronic hepatitis B patients. Methods: From 2012 to 2014, a cohort study was conducted among the chronic hepatitis B patients with sero-conversion of HBeAg in Jiangsu province. Association between participants' demographics, ALT, HBV DNA and incidence of HBeAg reversion was analyzed by Cox regression model. HBV DNA changing trend between patients with HBeAg reversion and patients with persistent HBeAg sero-conversion was compared by repeated measure data variance analysis. Results: In 2012, there were 5 068 HBeAg seroconverted chronic hepatitis B patients aged (51.9 ± 12.8) years enrolled. By 2014, HBeAg had reversed in 121 cases with the rate of 1.3/100 person-years. The probability of HBeAg reversion decreased with the age of the patients. By Cox regression analysis, HBV DNA level was an important influencing factor for the progress of HBeAg reversion. The patients with HBV DNA≥200 000 IU/ml had a higher HBeAg reversion rate DNA (3.8/100 person-years) than those with HBV DNA <2 000 IU/ml (1.1 person-years) (HR=3.44, 95% CI: 1.91-6.20, P=0.000). Compared with the persistent HBeAg sero-conversion group, HBV DNA and ALT showed a more dramatic increase in the HBeAg reversion group (P=0.000). Conclusions: There was a certain HBeAg reversion rate in chronic hepatitis B patients with HBeAg sero-conversion. Younger chronic CHB patients with HBeAg sero-conversion and those with higher HBV DNA lever had higher HBeAg reversion rate. Following up and management of chronic CHB patients with HBeAg sero-conversion is important and helpful for the control of hepatitis B.

[A cohort study on the epidemiological characteristics of HBeAg sero-clearance in HBeAg positive chronic hepatitis B patients in Jiangsu province from 2012 to 2014]

Objective: To understand the epidemiological characteristics and influencing factors related to HBeAg sero-clearance in chronic hepatitis B patients so as to provide evidence for regular management on chronic HBV patients. Methods: From 2012 to 2014, a cohort study was conducted among HBeAg positive chronic HBV patients in Jiangsu province. Association between the characteristics and incidence of HBeAg sero-clearance was analyzed by Cox regression method. The changing trend on HBV DNA between patients with HBeAg sero-clearance and those with persistent HBeAg positive status was compared by repeated measure data variance analysis method. Results: In 2012, there were 721 HBeAg positive hepatitis B patients aged (45.2 ± 14.2) years enrolled in this study. By 2014, the follow-up observation period was 1 058 person-years, and 393 cases had lost their HBeAg status, with the rate as 37.2/100 person-years. The HBeAg sero-clearance rate was 32.4/100 person-years in hepatitis B patients who received antiviral treatment. The probability of HBeAg clearance in HBeAg positive hepatitis B patients aged ≥60 year (62.0/100 person-years) was higher than those of aged <20 year (7.0/100 person-years). The rate of HBeAg sero-clearance in HBeAg positive patients with HBV DNA <20 000 IU/ml (75.8/100 person-years) was higher than those whose HBV DNA were ≥200 000 IU/ml (16.1/100 person-years). By Cox regression analysis, the HBV DNA level was an important influencing factor on the progress of HBeAg sero-clearance. Patients with HBV DNA levle as ≥200 000 IU/ml, had a lower HBeAg clearance rate (HR=0.18, 95%CI: 0.13-0.23, P<0.001). Compared to the persistent HBeAg positive group, HBV DNA showed a more dramatic fall in the HBeAg-lost group (P<0.001). Conclusion: The rate of HBeAg sero-clearance among HBeAg positive hepatitis B patients was correlated with age and HBV DNA status of the patients that called for comprehensive management and intervention programs to develop for the HBeAg positive hepatitis B patients with different characteristics.

[Microflora changes in upper digestive tract and bile in acute liver failure mice]

Objective: To study the changes of upper digestive tract and bile flora associated with acute liver failure in mice. Methods: Mice were randomly divided into 2 groups: control group and acute liver failure group (group M). Acute liver failure in group M was induced by intraperitoneal injection of D-galactosamine (D-GaIN). The information of relative abundance and diversity were observed by high-throughput sequencing of V3 + V4 region in 16 S rDNA from bacteria of oral cavity, stomach, duodenal and bile.Bacterial translocation and changes associated with acute liver injury were identified by LEfSe (LDA effect size) analysis. Results: At the phylum level, compared with control group, the relative abundance of TM7 in oral cavity and stomach increased in group M. At the family level, compared with control group, group M resulted in a significant decrease in Pasteurellaceae in the stomach (P<0.05) and a increase in Lactobacillaceae in the bile (P<0.05). Conclusion: The diversity of bacteria and relative abundance of each bacterium in upper digestive tract and the bile are significantly changed during the process of acute liver injure in mice.