Efficacy of different designs of mandibular expanders: A 3-dimensional finite element study.

INTRODUCTION: Nonsurgical mandibular expansion has been increasingly performed in recent years because it can effectively expand the mandibular dental arch. However, many types of mandibular expanders have been used in previous studies. No relevant studies have compared the biomechanical responses of different designs of mandibular expansion appliances with screws. Therefore, the purpose of this study was to analyze the stress distribution and displacement of the dentoalveolar structures according to different designs of mandibular screw expanders. METHODS: Cone-beam computed tomography scans were used for 3-dimensional reconstruction of the mandibular finite element model. Four different designs of mandibular expanders, 1 removable expander (type A) and 3 fixed expanders (types B, C, and D), were added to the finite element models. Expanders were activated transversely for 0.2 mm. The initial tooth displacement and von Mises stress distribution were evaluated. RESULTS: All the expanders enlarged the arch dimensions. In types A and B, the stress was mainly concentrated in the region of the anterior teeth, along with greater tooth displacement, whereas in types C and D, greater stress and displacement occurred in the region of the posterior teeth. Type A showed the greatest amount of transverse displacement. Type D was more efficient in the region of the posterior teeth. CONCLUSIONS: Types A and B should be used with great caution in the clinic because of their incompatible expansion pattern. Type D is the recommended mandibular expansion appliance because of its appropriate expansion pattern.

Serum hepatitis B virus RNA is encapsidated pregenome RNA that may be associated with persistence of viral infection and rebound.

BACKGROUND & AIMS: Hepatitis B virus (HBV) RNA in serum has recently been linked to efficacy and prognosis of chronic hepatitis B (CHB) treatment. This study explored the nature, origin, underlying mechanisms, and potential clinical significance of serum HBV RNA. METHODS: The levels of HBV DNA and RNA were determined in the supernatant of induced HepAD38, HBV-expressing HepG2.2.15 cells and primary human hepatocytes (PHH), and in the serum of transgenic mice and CHB patients. NP-40 and proteinase K treatment, sucrose density gradient centrifugation, electron microscopy, northern blot, multiple identification PCRs and 5' rapid-amplification of cDNA ends were performed to identify the nature of serum HBV RNA. RESULTS: Although significantly lower than HBV DNA levels, abundant HBV RNA was present in the serum of CHB patients. A series of experiments demonstrated that serum HBV RNA was pregenome RNA (pgRNA) and present in virus-like particles. HBV pgRNA virion levels increased after blocking the reverse transcription activity of HBV DNA polymerase, and decreased after blocking the encapsidation of pgRNA. Furthermore, the presence of HBV pgRNA virion was associated with risk of viral rebound after discontinuation of nucleot(s)ide analogues (NAs) therapy in CHB patients. CONCLUSIONS: Serum HBV RNA was confirmed to be pgRNA present in virus-like particles. HBV pgRNA virions were produced from encapsidated particles in which the pgRNA was non- or partially reverse transcribed. Clinically, HBV pgRNA virion might be a potential biomarker for monitoring safe discontinuation of NA-therapy. LAY SUMMARY: HBV may have another virion form in which the nucleic acid is composed of RNA, not DNA. The level of HBV RNA virion in serum may be associated with risk of HBV viral rebound after withdrawal of treatment, and therefore, a potential predictive biomarker to monitor the safe discontinuation of nucleot(s)ide analogues-therapy.

Study on lignin amination for lignin/SiO2 nano-hybrids towards sustainable natural rubber composites.

Lignin-based hybrid fillers are of increasing importance with regards to the valorization of low-value biomass and the requirement of sustainability in rubber industry, however, a facile lignin modification approach tuning the supramolecular interactions to favor the assembly of the hybrids is in demand. This study aimed to design a lignin/SiO2 nano-hybrid via an in-situ assembly of diethylamine grafted lignin (DL) and SiO2, and investigate its reinforcing effect on natural rubber (NR). DL was prepared through Mannich modification of lignin, and the grafted diethylamine can be clearly identified by FTIR, NMR and elemental analysis. The resultant hybrid (DLSi) displays as homogeneous nanospheres with well integrated DL and SiO2 components as shown in the TEM images, and the hybrid (DLSi1) prepared with weight ratio of DL/SiO2 = 1/2 shows a minimum particle size of 101.8 nm and significantly reduced polarity. Compared to the reference composite filled only with carbon black (CB), NR composites filled with DLSi/CB of 10/40 phr shows comparable mechanical properties and reduced rolling resistance, which is due to the low particle size, homogenous dispersion and strong rubber-filler interfacial affinity. Such remarkable performance suggests that the DLSi hybrid can be a promising versatile biobased filler for the application in gasoline-saving "green" tires.

Engineered bi-histidine metal chelation sites map the structure of the mechanical unfolding transition state of an elastomeric protein domain GB1.

Determining the structure of the transition state is critical for elucidating the mechanism behind how proteins fold and unfold. Due to its high free energy, however, the transition state generally cannot be trapped and studied directly using traditional structural biology methods. Thus, characterizing the structure of the transition state that occurs as proteins fold and unfold remains a major challenge. Here, we report a novel (to our knowledge) method that uses engineered bi-histidine (bi-His) metal-binding sites to directly map the structure of the mechanical unfolding transition state of proteins. This method is adapted from the traditional ψ-value analysis, which uses engineered bi-His metal chelation sites to probe chemical (un)folding transition-state structure. The φ(M2+)(U)-value is defined as ΔΔG(‡-N)/ΔΔG(U-N), which is the energetic effects of metal chelation by the bi-His site on the unfolding energy barrier (ΔG(‡-N)) relative to its thermodynamic stability (ΔG(U-N)) and can be used to obtain information about the transition state in the mutational site. As a proof of principle, we used the small protein GB1 as a model system and set out to map its mechanical unfolding transition-state structure. Using single-molecule atomic force microscopy and spectrofluorimetry, we directly quantified the effect of divalent metal ion binding on the mechanical unfolding free energy and thermodynamic stability of GB1, which allowed us to quantify φ(M2+)(U)-values for different sites in GB1. Our results enabled us to map the structure of the mechanical unfolding transition state of GB1. Within GB1's mechanical unfolding transition state, the interface between force-bearing ß-strands 1 and 4 is largely disrupted, and the first ß-hairpin is partially disordered while the second ß-hairpin and the α-helix remain structured. Our results demonstrate the unique application of ψ-value analysis in elucidating the structure of the transition state that occurs during the mechanical unfolding process, offering a potentially powerful new method for investigating the design of novel elastomeric proteins.

FeCl2-promoted cleavage of the unactivated C-C bond of alkylarenes and polystyrene: direct synthesis of arylamines.

Ironing it out: an efficient and convenient nitrogenation strategy involving C-C bond cleavage for the straightforward synthesis of versatile arylamines is presented. Various alkyl azides and alkylarenes, including the common industrial by-product cumene, react using this protocol. Moreover, this method provides a potential strategy for the degradation of polystyrene.

Protocol for rapid synthesis of high-performance ambipolar semiconducting polymers using an all-C-H-activation strategy.

Syntheses using classic coupling reactions can be tedious, leading to a dearth of ambipolar semiconducting polymers. Here, we detail the rapid synthesis of balanced ambipolar polymers by using a carbon-hydrogen (C-H) activation strategy. Using this protocol, two C-H reactive hydrogenated monomers and six ambipolar polymers can be rapidly synthesized within 2 h via C-H activation and the optoelectronic properties of the resultant polymers can be characterized. We also describe the fabrication process and performance evaluation of the ambipolar polymers-based organic transistors. For complete details on the use and execution of this protocol, please refer to Shen et al. (2022).

[Analysis on detection of enterovirus nucleotides in feces samples of hand-foot-mouth disease patients after recovery].

OBJECTIVE: To explore the duration of enterovirus (EV) nucleotides positive in feces samples of hand-foot-mouth disease (HFMD) patients after recovery. METHODS: A consecutive 6-week follow up were carried out towards 49 cases of laboratory-diagnosed HFMD patients. A total of 5 - 8 g feces sample was collected from each patient once a week. The common EV nucleotides of HFMD were detected by RT-PCR method and analyzed by Kaplan-Meier Survival Analysis Method. RESULTS: The subtypes of the 49 HFMD patients included 16 enterovirus 71 (EV71), 15 coxsackievirus A16 (CoxA16) and 18 EV; a six-week follow up was carried out among all of them. In the first week, one EV71 patient and two EV patients were lost; in the fourth week, one CoxA16 were lost; and in the fifth week, one EV71 patient was lost. During the consecutive 6-week follow-up, the positive rates of EV nucleotides among EV71 patients were 81.3%, 60.9%, 47.4%, 33.9%, 27.1% and 18.1% separately; and the positive rates in CoxA16 group were 93.3%, 73.3%, 53.3%, 33.3%, 16.7% and 8.3% respectively. In EV group, the positive rates of EV nucleotides were 44.4% and 7.4% in the first two weeks and then turned to negative in the next 4 weeks. There was significant statistical difference in positive rates of EV nucleotides among different patients (χ(2) = 11.78, P = 0.001); however, each group of HFMD patients showed a declined trend with the extension of time. CONCLUSION: The duration of EV nucleotides positive in feces samples of HFMD patients lasted for a long period since their recovery; and the positive results in EV71 and CoxA16 patients might last for 6 weeks.

A pilot study of mandibular expansion in combination with a fixed-appliance for increasing the effective space of the mandibular arch: Finite element analysis and three-dimensional cone-beam computed tomography.

ABSTRACT: Techniques for enhancing the effective space of the mandibular arch are urgently needed. Therefore, this study aimed to perform mandibular expansion in combination with a fixed-appliance technique, with preliminary monitoring by finite element analysis and 3-dimensional cone-beam computed tomography (CBCT).Finite element models were structured according to CBCT images of a 14-year-old girl. The von Mises stress of the alveolar bone and tooth displacement were assessed in different models. The technique was also applied in an 11-year-old boy. CBCT was performed at post-expansion, post-retention, post-treatment and 2 years after treatment. Tooth movement and alveolar bone stress were assessed by the CAD software.Finite element analysis suggested that the teeth tended to stand upright in the buccal side in the expander model compared with the expander-remove model. However, minimum tooth change was observed in the normal model, indicating highest stability. The von Mises stress of the alveolar bone was decreased in the normal model compared with the expander model, suggesting that buccal-inclined teeth could more easily lead to alveolar bone stress than normal ones. Based on CBCT data and the 3D mandibular dentition model fitting, mandibular teeth tended to be upright in the buccal side after retention compared with the post-expansion condition, which somewhat differed from finite element analysis results. Furthermore, dehiscence and fenestration were not observed.This expansion technique is expected to increase the effective space after mandibular expansion and reduce buccal alveolar bone stress.

In vitro anti­bacterial activity of diosgenin on Porphyromonas gingivalis and Prevotella intermedia.

Diosgenin (Dios), a natural steroidal sapogenin, is a bioactive compound extracted from dietary fenugreek seeds. It has a wide range of applications, exhibiting anti­oxidant, anti­inflammatory and anti­cancer activities. However, whether the extracts have beneficial effects on periodontal pathogens has so far remained elusive. The aim of the present study was to investigate the anti­bacterial effects of Dios on Porphyromonas gingivalis (P. gingivalis) and Prevotella intermedia (P. intermedia) in vitro. The anti­microbial effect of Dios on P. gingivalis and P. intermedia was assessed by a direct contact test (DCT) and the Cell Counting Kit (CCK)­8 assay at 60, 90 and 120 min. In addition, counting of colony­forming units (CFU) and live/dead cell staining were used to evaluate the anti­bacterial effects. The results of the DCT and CCK­8 assays indicated that Dios had beneficial dose­dependent inhibitory effects on P. gingivalis and P. intermedia. The CFU counting results also indicated that Dios had dose­dependent anti­bacterial effects on P. gingivalis and P. intermedia. Of note, Dios had significant anti­bacterial effects on the biofilms of P. gingivalis and P. intermedia in vitro as visualized by the live/dead cell staining method. In conclusion, the present results demonstrated that Dios had a marked anti­bacterial activity against P. gingivalis and P. intermedia in vitro, both in suspension and on biofilms. The present study highlighted the potential applications of Dios as a novel natural agent to prevent and treat periodontitis through its anti­bacterial effects.

Flow synthesis, characterization, anticoagulant activity of xylan sulfate from sugarcane bagasse.

High-value utilization of hemicellulose is critical to improve the append value of integrated biorefineries. In this research, the alkali-soluble sugarcane bagasse hemicellulose was sulfated using chlorosulfonic acid and N,N-dimethylformamide/LiCl under homogeneous conditions. With the aid of flow technique, a rapid, mild, and efficient method for the synthesis of xylan sulfate with high molecular weight and controllable degree of substitution was achieved. The results showed that the reaction time and the degradation of xylan chain were drastically reduced compared to the "in flask" batch conditions. High molecular weight of the product (Mw = 148,217) with a reasonable degree of substitution (DS = 1.49) could be obtained even at room temperature in 10 min under the present flow system. Anticoagulant experiments showed good anticoagulant activity of the resultant xylan sulfate, which could significantly prolong the activated partial thromboplastin time and thrombin time. This work not only provides a novel method for the synthesis of xylan sulfate, but also offers new opportunities for the production of other functional polysaccharide derivatives under the flow reaction conditions.

Enterovirus 71 vaccine acceptance among parents of children < 5 years old and their knowledge of hand, foot and mouth disease, Chongqing, China, 2017.

BACKGROUND: Enterovirus 71 (EV71) vaccine, which was put into market in China in 2016, has been viewed as a promising prevention measure against severe and fatal hand, foot and mouth disease (HFMD). This study aimed to investigate the knowledge of HFMD and acceptability of EV71 vaccine among parents of under-five in Chongqing, China. METHODOLOGY /PRINCIPAL FINDINGS: A cross-sectional survey was conducted in 2017. A validated questionnaire consisting of three sections including demographic information, knowledge of HFMD, acceptability and reasons for declining vaccination was developed based on literature review. Factors associated with unwillingness to receive EV71 vaccine were explored using multivariate logistic regression. A total of 992 parents finished the questionnaire with a response rate of 91.9%. Awareness of HFMD and EV71 vaccine were reported by 823 (83.0%) parents and 386 (38.9%) parents respectively. Knowledge about HFMD was with a mean score of 5.0 (standard deviation = 3.5) out of a total score of 12. Only 369 (37.2%) participants were classified as with good knowledge level about HFMD. 279 (28.1%) participants had their children received EV71 vaccine and 271 (27.3%) expressed willingness to vaccinate their children after a short-time education about EV71 vaccine. Acceptability of EV71 vaccine increased along with parents' education level (p = 0.008) and HFMD knowledge level (p<0.001). Parents of scattered children had higher acceptability than those of preschool children (p = 0.002). 442 (44.6%) of participants were unwilling to have their children vaccinated with EV71 vaccine. The most common reasons for declining EV71 vaccine were doubts about its safety (56.6%) and efficacy (48.3%), and the necessity of vaccination (38.3%). Physicians and vaccination certificate were the parents' most trusted sources of vaccine information. CONCLUSIONS: Parents' knowledge about HFMD was not sufficient, and nearly half of the parents expressed unwillingness to vaccinate their children with EV71 vaccine. Our findings stress that more efforts by health authorities in Chongqing are needed to increase the acceptability of EV71 vaccine, especially among parents of preschool children with lower education level.

Prevention of in-stent restenosis with endothelial progenitor cell (EPC) capture stent placement combined with regional EPC transplantation: An atherosclerotic rabbit model.

BACKGROUND: Even with drug-eluting stents, the risk of in-stent restenosis (ISR) remains high. The goal of this study was to investigate the use of an endothelial progenitor cell (EPC) capture stent plus regional EPC transplantation to reduce the ISR rate. METHODS: Endothelial progenitor cell capture stents were fabricated using fibrin gel and anti-CD34 plus anti-VEGFR-2 dual antibodies. Twenty male New Zealand white rabbits established as an atherosclerotic model were randomly divided into two groups: group 1 (n = 10), in which EPC capture stents were deployed into the right iliac artery; and group 2 (n = 10), in which sirolimus-eluting stents were placed. In both groups, EPCs were transplanted into target vessels beyond the stents, with outflow blocked. Radiologic-pathologic correlation outcomes were reviewed after 2 months. RESULTS: The technical success rate of EPC capture stent placement plus EPC transplantation was 100%. The ISR rate in group 1 was lower than in group 2 (1/10 vs. 4/10; p > 0.05). Minimal luminal diameters were larger in group 1 than in group 2 (computed tomographic angiography, 1.85 ± 0.15 mm vs. 1.50 ± 0.20 mm; duplex ultrasound, 1.90 ± 0.10 mm vs. 1.70 ± 0.30 mm; p > 0.05). Transplanted EPCs were tracked positively only in group 1. Pathologic analysis demonstrated neointimal hyperplasia thickness of 0.21 ± 0.09 mm in group 1 vs. 0.11 ± 0.07 mm in group 2 (p < 0.05). CONCLUSION: Endothelial progenitor cell capture stent placement plus local EPC transplant decreases the ISR rate through thrombosis reduction rather than through neointimal hyperplasia inhibition.

Regeneration of osteochondral defects in vivo by a cell-free cylindrical poly(lactide-co-glycolide) scaffold with a radially oriented microstructure.

A scaffold with an oriented porous architecture to facilitate cell infiltration and bioactive interflow between neo-host tissues is of great importance for in situ inductive osteochondral regeneration. In this study, a poly(lactide-co-glycolide) (PLGA) scaffold with oriented pores in its radial direction was fabricated via unidirectional cooling of the PLGA solution in the radial direction, following with lyophilization. Micro-computed tomography evaluation and scanning electron microscopy observation confirmed the radially oriented microtubular pores in the scaffold. The scaffold had porosity larger than 90% and a compressive modulus of 4 MPa in a dry state. Culture of bone marrow stem cells in vitro revealed faster migration and regular distribution of cells in the poly(lactide-co-glycolide) scaffold with oriented pores compared with the random PLGA scaffold. The cell-free oriented macroporous PLGA scaffold was implanted into rabbit articular osteochondral defect in vivo for 12 weeks to evaluate its inductive tissue regeneration function. Histological analysis confirmed obvious tide mark formation and abundant chondrocytes distributed regularly with obvious lacunae in the cartilage layer. Safranin O-fast green staining showed an obvious boundary between the two layers with distinct staining results, indicating the simultaneous regeneration of the cartilage and subchondral bone layers, which is not the case for the random poly(lactide-co-glycolide) scaffold after the same implantation in vivo. The oriented macroporous PLGA scaffold is a promising material for the in situ inductive osteochondral regeneration without the necessity of preseeding cells.

A density gradient of VAPG peptides on a cell-resisting surface achieves selective adhesion and directional migration of smooth muscle cells over fibroblasts.

Selective adhesion and migration of smooth muscle cells (SMCs) over fibroblasts (FIBs) is required to prevent adventitia fibrosis in vascular regeneration. In this study, a uniform cell-resisting layer of poly(ethylene glycol) (PEG) with a density gradient of azide groups was generated on a substrate by immobilizing two kinds of PEG molecules in a gradient manner. A density gradient of alkynyl-functionalized Val-Ala-Pro-Gly (VAPG) peptides was then prepared on the PEG layer via click chemistry. The VAPG density gradient was characterized by fluorescence imaging, revealing the gradual enhancement of the fluorescent intensity along the substrate direction. The adhesion and mobility of SMCs were selectively enhanced on the VAPG density gradient, leading to directional migration toward the higher peptide density (up to 84%). In contrast, the adhesion and mobility of FIBs were significantly weakened. The net displacement of SMCs also significantly increased compared with that on tissue culture polystyrene (TCPS) and that of FIBs on the gradient. The mitogen-activated protein kinase (MAPK) signaling pathways related to cell migration were studied, showing higher expressions of functional proteins from SMCs on the VAPG-modified surface in a density-dependent manner. For the first time the selective adhesion and directional migration of SMCs over FIBs was achieved by an elaborative design of a gradient surface, leading to a new insight in design of novel vascular regenerative materials. STATEMENT OF SIGNIFICANCE: Selective cell adhesion and migration guided by regenerative biomaterials are extremely important for the regeneration of targeted tissues, which can avoid the drawbacks of incorrect and uncontrolled responses of tissue cells to implants. For example, selectivity of smooth muscle cells (SMCs) over fibroblasts (FIBs) is required to prevent adventitia fibrosis in vascular regeneration. Herein we prepare a uniform cell-repelling layer, on which SMCs-selective Val-Ala-Pro-Gly (VAPG) peptides are immobilized in a continuous manner. Selective adhesion and enhanced and directional migration of SMCs over FIBs are achieved by the interplay of cell-repelling layer and gradient SMCs-selective VAPG peptides, paving a new way for the design of novel vascular grafts with enhanced biological performance.

Hydrazine hydrate and organosolv synergetic pretreatment of corn stover to enhance enzymatic saccharification and co-production of high-quality antioxidant lignin.

Hydrazine hydrate and organosolv synergetic pretreatment of corn stover was developed. With the aid of alkaline and reductive hydrazine hydrate, a high delignification rate (77.94%) and total sugar yield of 90.27% (96.60% glucose, 78.82% xylose) based on the pulp could be obtained using hydrazine hydrate (10 mmol/g corn stover) and aqueous ethanol (60 vt%) as the solvent system. Analysis techniques such as FT-IR, SEM, XRD, and NMR were employed to characterize the structure and property changes of stock before and after pretreatment to evaluate the effect of hydrazine hydrate. A mechanism is proposed for the presented system.

Epidemiological Characteristics and Spatial-Temporal Distribution of Hand, Foot, and Mouth Disease in Chongqing, China, 2009-2016.

(1) Objective: Even with licensed vaccine for enterovirus 71 (EV71) put into market in 2016 in China, hand, foot, and mouth disease (HFMD) is still a threat for children's health in Chongqing. We described the epidemiological characteristics and spatial-temporal patterns of HFMD in Chongqing from 2009 to 2016, in order to provide information and evidence for guiding public health response and intervention. (2) Methods: We retrieved the HFMD surveillance data from January 2009 to December 2016 from "National Disease Reporting Information System", and then analyzed demographic and geographical information integrally. Descriptive analysis was conducted to evaluate the epidemic features of HFMD in Chongqing. The spatial-temporal methods were performed to explore the clusters at district/county level. (3) Results: A total of 276,207 HFMD cases were reported during the study period (total population incidence: 114.8 per 100,000 per year), including 641 severe cases (129 deaths). The annual incidence of HFMD sharply increased in even-numbered years, but remained stable or decreased in odd-numbered years. A semiannual seasonality was observed during April to July, and October to December in each year. The male-to-female ratios of the mild and severe cases were 1.4:1 and 1.5:1, with the median age of 2.3 years and 1.9 years, respectively. More than 90% of the cases were children equal to and less than 5 years old. High-incidence clustered regions included the main urban districts and northeast regions according to incidence rates comparison or space-time cluster analysis. A total of 19,482 specimen were collected from the reported cases and 13,277 (68.2%) were positive for enterovirus. EV71 was the major causative agent for severe cases, while other enteroviruses were the predominant serotype for mild cases. (4) Conclusions: The characteristics of HFMD in Chongqing exhibited a phenomenon of increasing incidence in two-year cycles and semiannual seasonality in time distribution. Children ≤5 years old, especially boys, were more affected by HFMD. EV71 was the major causative agent for severe cases. We suggest initiating mass EV71 vaccination campaigns among children aged 6 months to 5 years in Chongqing, especially in the main urban districts and northern regions, in order to reduce case fatality, and take integrated measurements for controlling and preventing HFMD attributed to other enteroviruses.

Organic amine catalytic organosolv pretreatment of corn stover for enzymatic saccharification and high-quality lignin.

A novel and efficient organic amine and organosolv synergetic pretreatment method was developed to overcome the recalcitrance of lignocellulose to produce fermentable sugars and high-quality salt-free lignin. After optimization of the process parameters, a delignification of 81.7% and total sugar yield of 83.2% (87.1% glucose, 75.4% xylose) could be obtained using n-propylamine (10mmol/g, biomass) as a catalyst and aqueous ethanol (60%, v/v) as a solvent. The susceptibility of the substrates to enzymatic digestibility was explained by their physical and chemical characteristics. The physical structure of extracted lignin showed higher ß-aryl ether bonds content and functionalities, offering the potential for further downstream upgrading. The role of organic amine catalyst and a synergistic mechanism is proposed for the present system.

Serum cholinesterase: a potential assistant biomarker for hand, foot, and mouth disease caused by enterovirus 71 infection.

BACKGROUND: Hand, foot, and mouth disease (HFMD) caused by enterovirus 71 (EV71) is a potentially life-threatening infectious disease that commonly occurs in children. Diagnosis of HFMD caused by EV71 largely depends on clinical manifestations and rare serological biomarkers used to identify children suffering from HFMD. Serum cholinesterase (SChE) activity has frequently been reported as a potential biomarker for solid central nervous system tumors, chronic heart failure, and liver cirrhosis. However, its potential value in the diagnosis of neurotropic virus infections, such as HFMD caused by EV71, remains to be determined. FINDINGS: In our study, 220 children hospitalized with HFMD caused by EV71, 34 inpatients infected with coxsackievirus A16 (CVA16), and 43 undefined enterovirus-infected HFMD inpatients were recruited at the Anhui Provincial Children's Hospital between January 2011 and December 2012. SChE activity was measured. The non-parametric Mann-Whitney U test showed that SChE activity in children diagnosed with HFMD caused by EV71 was significantly higher than in healthy controls (p < 0.001), as well as in children with upper respiratory tract infections (p = 0.011), bronchopneumonia (p < 0.001), septicemia (p < 0.001), amygdalitis (p < 0.001), and appendicitis (p < 0.001). In addition, higher SChE activity was observed in male inpatients with HFMD caused by EV71 (47.7 % positivity) compared to female inpatients (26.1 % positivity) (chi-square test, p = 0.002). In our study, no significant differences in SChE levels were observed among different ages (up to 120 months) (r = -0.112, p > 0.05). An important finding was that SChE activity declined in the recovery phase of HFMD caused by EV71 compared to the acute phase (p < 0.001). CONCLUSIONS: Elevated SChE activity was observed in patients with severe HFMD caused by EV71. Therefore, SChE might be a potential assistant biomarker for the diagnosis of HFMD caused by EV71 in children.

Gene sequencing and variable site analyzing of coding region of two enterovirus A71 isolates with different clinical phenotypes.

Currently, it is still controversial that if the pathogenicity of EV-A71 causing severe or mild hand, foot, and mouth disease (HFMD) is associated with viral nucleotide or amino acid sequence(s). In this study, 19 clinical strains were detected in samples from diagnosed patients of EV-A71-caused HFMD with mild or severe symptoms. Then, VP1-2A fragment sequences of 19 EV-A71 isolates were determined, the phylogenetic analysis, based on VP1 sequences of 19 EV-A71 stains in this study and which of 62 EV-A71 strains with different clinical phenotypes reported before, were carried out. Our results showed that no difference in the genotype and evolution distribution was observed among the EV-A71 strains mentioned above. Furthermore, two EV-A71 isolates, which with much close evolutionary relationship but different clinical manifestations, were purified by plaque assay, the complete genome sequencing was done, and deduced amino acid sequence analysis of 11 proteins coded by EV-A71 was carried out. Eight variable amino acid sites were found and further verified with those of 62 strains reported before. Our study provides further evidence that the potential pathogenicity of EV-A71 causing severe or mild HFMD seems not to be associated with viral genotype and even the amino acid substitution.