Mechanism of Learning and Memory Impairment in Rats Exposed to Arsenic and/or Fluoride Based on Microbiome and Metabolome / 生物医学与环境科学（英文）

OBJECTIVE@#Arsenic (As) and fluoride (F) are two of the most common elements contaminating groundwater resources. A growing number of studies have found that As and F can cause neurotoxicity in infants and children, leading to cognitive, learning, and memory impairments. However, early biomarkers of learning and memory impairment induced by As and/or F remain unclear. In the present study, the mechanisms by which As and/or F cause learning memory impairment are explored at the multi-omics level (microbiome and metabolome).@*METHODS@#We stablished an SD rats model exposed to arsenic and/or fluoride from intrauterine to adult period.@*RESULTS@#Arsenic and/fluoride exposed groups showed reduced neurobehavioral performance and lesions in the hippocampal CA1 region. 16S rRNA gene sequencing revealed that As and/or F exposure significantly altered the composition and diversity of the gut microbiome，featuring the Lachnospiraceae_NK4A136_group, Ruminococcus_1, Prevotellaceae_NK3B31_group, [Eubacterium]_xylanophilum_group. Metabolome analysis showed that As and/or F-induced learning and memory impairment may be related to tryptophan, lipoic acid, glutamate, gamma-aminobutyric acidergic (GABAergic) synapse, and arachidonic acid (AA) metabolism. The gut microbiota, metabolites, and learning memory indicators were significantly correlated.@*CONCLUSION@#Learning memory impairment triggered by As and/or F exposure may be mediated by different gut microbes and their associated metabolites.

Ultrapotent SARS-CoV-2 neutralizing antibodies with protective efficacy against newly emerged mutational variants

Accumulating mutations in the SARS-CoV-2 Spike (S) protein can increase the possibility of immune escape, challenging the present COVID-19 prophylaxis and clinical interventions. Here, 3 receptor binding domain (RBD) specific monoclonal antibodies (mAbs), 58G6, 510A5 and 13G9, with high neutralizing potency blocking authentic SARS-CoV-2 virus displayed remarkable efficacy against authentic B.1.351 virus. Each of these 3 mAbs in combination with one neutralizing Ab recognizing non-competing epitope exhibited synergistic effect against authentic SARS-CoV-2 virus. Surprisingly, structural analysis revealed that 58G6 and 13G9, encoded by the IGHV1-58 and the IGKV3-20 germline genes, both recognized the steric region S470-495 on the RBD, overlapping the E484K mutation presented in B.1.351. Also, 58G6 directly bound to another region S450-458 in the RBD. Significantly, 58G6 and 510A5 both demonstrated prophylactic efficacy against authentic SARS-CoV-2 and B.1.351 viruses in the transgenic mice expressing human ACE2 (hACE2), protecting weight loss and reducing virus loads. These 2 ultrapotent neutralizing Abs can be promising candidates to fulfill the urgent needs for the prolonged COVID-19 pandemic.

Distinct mechanisms for TMPRSS2 expression explain organ-specific inhibition of SARS-CoV-2 infection by enzalutamide

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly become a global public health threat due to the lack of effective drugs or vaccines against SARS-CoV-2. The efficacy of several repurposed drugs has been evaluated in clinical trials. Among these drugs, a relatively new antiandrogen agent, enzalutamide, was proposed because it reduces the expression of transmembrane serine protease 2 (TMPRSS2), a key component mediating SARS-CoV-2-driven entry into host cells, in prostate cancer cells. However, definitive evidence for the therapeutic efficacy of enzalutamide in COVID-19 is lacking. Here, we evaluated the antiviral efficacy of enzalutamide in prostate cancer cells, lung cancer cells, human lung organoids and SARS-CoV-2-infected Ad-ACE2-transduced Tmprss2 knockout (Tmprss2-KO) and wild-type (WT) mice. TMPRSS2 knockout significantly inhibited SARS-CoV-2 infection in vivo. Enzalutamide effectively inhibited SARS-CoV-2 infection in human prostate cancer cells (LNCaP) but not in human lung cancer cells or patient-derived lung organoids. Although Tmprss2 knockout effectively blocked SARS-CoV-2 infection in ACE2-transduced mice, enzalutamide showed no antiviral activity due to the AR independence of TMPRSS2 expression in mouse and human lung epithelial cells. Moreover, we observed distinct AR binding patterns between prostate cells and lung cells and a lack of direct binding of AR to TMPRSS2 in human lung cells. Thus, our findings do not support the postulated protective role of enzalutamide in treating COVID-19.

A key linear epitope for a potent neutralizing antibody to SARS-CoV-2 S-RBD

The spread of SARS-CoV-2 confers a serious threat to the public health without effective intervention strategies1-3. Its variant carrying mutated Spike (S) protein D614G (SD614G) has become the most prevalent form in the current global pandemic4,5. We have identified a large panel of potential neutralizing antibodies (NAbs) targeting the receptor-binding domain (RBD) of SARS-CoV-2 S6. Here, we focused on the top 20 potential NAbs for the mechanism study. Of them, the top 4 NAbs could individually neutralize both authentic SARS-CoV-2 and SD614G pseudovirus efficiently. Our epitope mapping revealed that 16/20 potent NAbs overlapped the same steric epitope. Excitingly, we found that one of these potent NAbs (58G6) exclusively bound to a linear epitope on S-RBD (termed as 58G6e), and the interaction of 58G6e and the recombinant ACE2 could be blocked by 58G6. We confirmed that 58G6e represented a key site of vulnerability on S-RBD and it could positively react with COVID-19 convalescent patients plasma. We are the first, as far as we know, to provide direct evidences of a linear epitope that can be recognized by a potent NAb against SARS-CoV-2 S-RBD. This study paves the way for the applications of these NAbs and the potential safe and effective vaccine design.

Interaction network of SARS-CoV-2 with host receptome through spike protein

Host cellular receptors are key determinants of virus tropism and pathogenesis. Virus utilizes multiple receptors for attachment, entry, or specific host responses. However, other than ACE2, little is known about SARS-CoV-2 receptors. Furthermore, ACE2 cannot easily interpret the multi-organ tropisms of SARS-CoV-2 nor the clinical differences between SARS-CoV-2 and SARS-CoV. To identify host cell receptors involved in SARS-CoV-2 interactions, we performed genomic receptor profiling to screen almost all human membrane proteins, with SARS-CoV-2 capsid spike (S) protein as the target. Twelve receptors were identified, including ACE2. Most receptors bind at least two domains on S protein, the receptor-binding-domain (RBD) and the N-terminal-domain (NTD), suggesting both are critical for virus-host interaction. Ectopic expression of ASGR1 or KREMEN1 is sufficient to enable entry of SARS-CoV-2, but not SARS-CoV and MERS-CoV. Analyzing single-cell transcriptome profiles from COVID-19 patients revealed that virus susceptibility in airway epithelial ciliated and secretory cells and immune macrophages highly correlates with expression of ACE2, KREMEN1 and ASGR1 respectively, and ACE2/ASGR1/KREMEN1 (ASK) together displayed a much better correlation than any individual receptor. Based on modeling of systemic SARS-CoV-2 host interactions through S receptors, we revealed ASK correlation with SARS-CoV-2 multi-organ tropism and provided potential explanations for various COVID-19 symptoms. Our study identified a panel of SARS-CoV-2 receptors with diverse binding properties, biological functions, and clinical correlations or implications, including ASGR1 and KREMEN1 as the alternative entry receptors, providing insights into critical interactions of SARS-CoV-2 with host, as well as a useful resource and potential drug targets for COVID-19 investigation.

Engineered Trimeric ACE2 Binds and Locks "Three-up" Spike Protein to Potently Inhibit SARS-CoVs and Mutants

SARS-CoV-2 enters cells via ACE-2, which binds the spike protein with moderate affinity. Despite a constant background mutational rate, the virus must retain binding with ACE2 for infectivity, providing a conserved constraint for SARS-CoV-2 inhibitors. To prevent mutational escape of SARS-CoV-2 and to prepare for future related coronavirus outbreaks, we engineered a de novo trimeric ACE2 (T-ACE2) protein scaffold that binds the trimeric spike protein with extremely high affinity (KD < 1 pM), while retaining ACE2 native sequence. T-ACE2 potently inhibits all tested pseudotyped viruses including SARS-CoV-2, SARS-CoV, eight naturally occurring SARS-CoV-2 mutants, two SARSr-CoVs as well as authentic SARS-CoV-2. The cryo-EM structure reveals that T-ACE2 can induce the transit of spike protein to "three-up" RBD conformation upon binding. T-ACE2 thus represents a promising class of broadly neutralizing proteins against SARS-CoVs and mutants.

The S1/S2 boundary of SARS-CoV-2 spike protein modulates cell entry pathways and transmission

The global spread of SARS-CoV-2 is posing major public health challenges. One unique feature of SARS-CoV-2 spike protein is the insertion of multi-basic residues at the S1/S2 subunit cleavage site, the function of which remains uncertain. We found that the virus with intact spike (Sfull) preferentially enters cells via fusion at the plasma membrane, whereas a clone (Sdel) with deletion disrupting the multi-basic S1/S2 site instead utilizes a less efficient endosomal entry pathway. This idea was supported by the identification of a suite of endosomal entry factors specific to Sdel virus by a genome-wide CRISPR-Cas9 screen. A panel of host factors regulating the surface expression of ACE2 was identified for both viruses. Using a hamster model, animal-to-animal transmission with the Sdel virus was almost completely abrogated, unlike with Sfull. These findings highlight the critical role of the S1/S2 boundary of the SARS-CoV-2 spike protein in modulating virus entry and transmission.

A rapid and efficient screening system for neutralizing antibodies and its application for the discovery of potent neutralizing antibodies to SARS-CoV-2 S-RBD

Neutralizing antibodies (Abs) have been considered as promising therapeutics for the prevention and treatment of pathogens. After the outbreak of COVID-19, potent neutralizing Abs to SARS-CoV-2 were promptly developed, and a few of those neutralizing Abs are being tested in clinical studies. However, there were few methodologies detailly reported on how to rapidly and efficiently generate neutralizing Abs of interest. Here, we present a strategically optimized method for precisive screening of neutralizing monoclonal antibodies (mAbs), which enabled us to identify SARS-CoV-2 receptor-binding domain (RBD) specific Abs within 4 days, followed by another 2 days for neutralization activity evaluation. By applying the screening system, we obtained 198 Abs against the RBD of SARS-CoV-2. Excitingly, we found that approximately 50% (96/198) of them were candidate neutralizing Abs in a preliminary screening of SARS-CoV-2 pseudovirus and 20 of these 96 neutralizing Abs were confirmed with high potency. Furthermore, 2 mAbs with the highest neutralizing potency were identified to block authentic SARS-CoV-2 with the half-maximal inhibitory concentration (IC50) at concentrations of 9.88 ng/ml and 11.13 ng/ml. In this report, we demonstrated that the optimized neutralizing Abs screening system is useful for the rapid and efficient discovery of potent neutralizing Abs against SARS-CoV-2. Our study provides a methodology for the generation of preventive and therapeutic antibody drugs for emerging infectious diseases.

Immunization with the receptor-binding domain of SARS-CoV-2 elicits antibodies cross-neutralizing SARS-CoV-2 and SARS-CoV without antibody-dependent enhancement

Recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen responsible for the ongoing coronavirus disease 2019 (COVID-19) pandemic. Currently, there is no vaccine available for preventing SARS-CoV-2 infection. Like closely related severe acute respiratory syndrome coronavirus (SARS-CoV), SARS-CoV-2 also uses its receptor-binding domain (RBD) on the spike (S) protein to engage the host receptor, human angiotensin-converting enzyme 2 (ACE2), facilitating subsequent viral entry. Here we report the immunogenicity and vaccine potential of SARS-CoV-2 RBD (SARS2-RBD)-based recombinant proteins. Immunization with SARS2-RBD recombinant proteins potently induced a multi-functional antibody response in mice. The resulting antisera could efficiently block the interaction between SARS2-RBD and ACE2, inhibit S-mediated cell-cell fusion, and neutralize both SARS-CoV-2 pseudovirus entry and authentic SARS-CoV-2 infection. In addition, the anti-RBD sera also exhibited cross binding, ACE2-blockade, and neutralization effects towards SARS-CoV. More importantly, we found that the anti-RBD sera did not promote antibody-dependent enhancement of either SARS-CoV-2 pseudovirus entry or authentic virus infection of Fc receptor-bearing cells. These findings provide a solid foundation for developing RBD-based subunit vaccines for SARS-CoV2.

Potent antiviral effect of protoporphyrin IX and verteporfin on SARS-CoV-2 infection

The SARS-CoV-2 infection is spreading rapidly worldwide. Efficacious antiviral therapeutics against SARS-CoV-2 is urgently needed. Here, we discovered that protoporphyrin IX (PpIX) and verteporfin, two FDA-approved drugs, completely inhibited the cytopathic effect produced by SARS-CoV-2 infection at 1.25 M and 0.31 M respectively, and their EC50 values of reduction of viral RNA were at nanomolar concentrations. The selectivity indices of PpIX and verteporfin were 952.74 and 368.93, respectively, suggesting broad margin of safety. Importantly, PpIX and verteporfin prevented SARS-CoV-2 infection in mice adenovirally transduced with human ACE2. The compounds, sharing a porphyrin ring structure, were shown to bind viral receptor ACE2 and interfere with the interaction between ACE2 and the receptor-binding domain of viral S protein. Our study suggests that PpIX and verteporfin are potent antiviral agents against SARS-CoV-2 infection and sheds new light on developing novel chemoprophylaxis and chemotherapy against SARS-CoV-2.

Stability of the COVID-19 virus under wet, dry and acidic conditions

COVID-19 has become a pandemic and is spreading fast worldwide. The COVID-19 virus is transmitted mainly through respiratory droplets and close contact. However, the fecal-oral transmission of the virus has not been ruled out and it is important to ascertain how acidic condition in the stomach affects the infectivity of the virus. Besides, it is unclear how stable the COVID-19 virus is under dry and wet conditions. In the present study, we have shown that the COVID-19 virus is extremely infectious as manifested by the infection of Vero-E6 cells by one PFU (Plaque Forming Unit) of the virus. We then investigated the stability of the COVID-19 virus in wet, dry and acidic (pH2.2) environments at room temperature. Results showed that the COVID-19 virus could survive for three days in wet and dry environments, but the dry condition is less favorable for the survival of the virus. Our study also demonstrated that the COVID-19 virus at a relative high titer (1.2 x 103 PFU) exhibits a certain degree of tolerance to acidic environment at least for 60 minutes. When the virus titer was [≤]1.0 x 103 PFU, acid treatment (pH2.2) for 30 or 60 minute resulted in virus inactivation. It suggests that the virus at a high concentration may survive in the acidic environment of the stomach. The finding of the present study will contribute to the control of the spread of the COVID-19 virus.

Filamentation initiated by Cas2 and its association with the acquisition process in cells / 国际口腔科学杂志·英文版

Cas1-and-Cas2-mediated new spacer acquisition is an essential process for bacterial adaptive immunity. The process is critical for the ecology of the oral microflora and oral health. Although molecular mechanisms for spacer acquisition are known, it has never been established if this process is associated with the morphological changes of bacteria. In this study, we demonstrated a novel Cas2-induced filamentation phenotype in E. coli that was regulated by co-expression of the Cas1 protein. A 30 amino acid motif at the carboxyl terminus of Cas2 is necessary for this function. By imaging analysis, we provided evidence to argue that Cas-induced filamentation is a step coupled with new spacer acquisition during which filaments are characterised by polyploidy with asymmetric cell division. This work may open new opportunities to investigate the adaptive immune response and microbial balance for oral health.

Advances in two-component signal transduction system VraSR of Staphylococcus / 中华微生物学和免疫学杂志

Staphylococcus utilizes vancomycin-resistance associated sensor/regulator ( VraSR) , a two-component signal transduction system ( TCS) , to sense and respond to cell wall damage and to adapt to environmental changes through regulating transcriptions of downstream genes. It has been indicated that VraSR can regulate the transcription of a series of genes involved in the synthesis of peptidoglycan, drug re-sistance, and virulence in Staphylococcus aureus ( S. aureus) . A similar two-component system, VraSR, is also present in Staphylococcus epidermidis ( S. epidermidis ) , sharing a high homology with the VraSR of S. aureus. Little is known about the functions of VraSR in S. epidermidis and it is not yet clear what the simi-larities and differences in resistance and pathogenicity are. Based on the previous work of our group, a brief review on the regulation mechanism of staphylococcal VraSR was performed.

Effects of ginseng neutral polysaccharide on gut microbiota in antibiotic-associated diarrhea mice / 中国中药杂志

To investigate the effect of ginseng neutral polysaccharide on gut microbiota composition and diversity as well as the therapeutic effect for antibiotic associated diarrhea( AAD) in mice. The water-soluble ginseng neutral polysaccharide( WGPN) was purified from water-soluble ginseng polysaccharides( WGP) by DEAE-sepharose fast flow column,which was obtained from the roots of Panax ginseng. AAD mice were induced by gastric gavage with lincomycin hydrochloride,followed by administration of normal saline( natural recovery group,NR) or WGPN( WGPN group) for one week. Body weight changes,psychosis and diarrhea status were observed and assessed. 12 h after the last administration,histological observation of ileum and 16 S rRNA high throughput sequencing analysis of intestinal contents were conducted to identify the effects of WGPN on AAD mice. The results showed that WGPN could alleviate the symptoms of diarrhea in mice,decrease the inflammation and edema of ileum,and increase the length of intestinal villi. As compared to NR mice,WGPN could increase the relative abundance of Lactobacillus,and significantly decrease the relative abundance of Bacteroides,Streptococcus,Ochrobactrum and Pseudomonas at the genus level. In conclusion,WGPN could improve the gut microecology by recovering the ileum structure and improving the diversity and composition of the gut microbiota in AAD mice.

Investigation on the status of 3-14 years old children with cerebral palsy in Liaoning / 中国医师进修杂志

Objective To investigate the status on children of 3-14 years old who suffered from cerebral palsy in Liaoning province. Methods One thousand three hundred and twenty-three cases of children with cerebral palsy of 3-14 years old who received rehabilitation in city hospital, county hospital and community hospital were investigated from January 2013 to October 2016 in 14 cities in Liaoning Province. The proportion of cerebral palsy children in 3-4 years old, 4-5 years old, 8-9 years old, 5-6 years old , 6-7 years old and 7-8 years old was about 10%, and in the other age the proportion was about 7%. The proportion of men and women generally was 4:1;neonatal convulsion (252 cases, 19%), premature delivery (230 cases , 17.3%) and low birth weight infant (187 cases, 14.1%) were main risk factors and accounted for more than 10%. Spastic type cerebral palsy accounted for the highest proportion (54.35%, 719 cases)and ataxia cerebral palsy accounted for the lowest proportion (2.95%). In complications , lower intelligence accounted for the highest proportion (50.34%, 666 cases), followed by the language barrier (43.99% , 582 cases), and the other complications accounted for less than 10%.;gross motor function classification in most studied children was stageⅡ(35%) and stageⅢ(32.50%); 6.95% patients could go to school, and 84.96% patients had health insurance. Patients coming from city accounted for 69.01%, and patients coming from rural area accounted for 30.99%. Mothers′ education below primary school was 4.16% . 36.05% children received rehabilitation in comprehensive hospital, 60.09%in children′s hospital and 3.85%in maternal and child health hospital. Conclusions Spastic cerebral palsy is the main type of children with cerebral palsy in Liaoning.High risk factors include neonatal convulsions, premature birth and low birth weight infants. Most patients complicate with low intelligence and language barriers.This paper can be used as the basis of further research on prevention and treatment

Pneumoperitoneum simulation based on mass-spring-damper models for laparoscopic surgical planning.

Laparoscopic surgery, which is one minimally invasive surgical technique that is now widely performed, is done by making a working space (pneumoperitoneum) by infusing carbon dioxide ([Formula: see text]) gas into the abdominal cavity. A virtual pneumoperitoneum method that simulates the abdominal wall and viscera motion by the pneumoperitoneum based on mass-spring-damper models (MSDMs) with mechanical properties is proposed. Our proposed method simulates the pneumoperitoneum based on MSDMs and Newton's equations of motion. The parameters of MSDMs are determined by the anatomical knowledge of the mechanical properties of human tissues. Virtual [Formula: see text] gas pressure is applied to the boundary surface of the abdominal cavity. The abdominal shapes after creation of the pneumoperitoneum are computed by solving the equations of motion. The mean position errors of our proposed method using 10 mmHg virtual gas pressure were [Formula: see text], and the position error of the previous method proposed by Kitasaka et al. was 35.6 mm. The differences in the errors were statistically significant ([Formula: see text], Student's [Formula: see text]-test). The position error of the proposed method was reduced from [Formula: see text] to [Formula: see text] using 30 mmHg virtual gas pressure. The proposed method simulated abdominal wall motion by infused gas pressure and generated deformed volumetric images from a preoperative volumetric image. Our method predicted abdominal wall deformation by just giving the [Formula: see text] gas pressure and the tissue properties. Measurement of the visceral displacement will be required to validate the visceral motion.

Effect of bevacizumab on proliferation and invasion of human lung cancer A549 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effect and mechanism of bevacizumab on proliferation and invasion of human lung cancer A549 cells.</p><p><b>METHODS</b>A549 cells were treated with bevacizumab. Proliferation and invasion of the bevacizumab-treated A549 cells were detected using cell counting kit CCK-8 and Transwell assay, respectively. The expression of the mRNA and protein of MMP-2, MMP-9 and c-Met were detected by real-time PCR and Western blotting, respectively.</p><p><b>RESULTS</b>Proliferation activity was inhibited at the concentration of 10 µg/ml and promoted at the concentration of 100 µg/ml bevacizumab. Bevacizumab in the concentration of 50 µg/ml had a stronger inhibitory effect on the invasion of A549 cells (16 406.19 ± 5 674.23 penetrated cells) than that of control group (36 108.68 6 263.83, P<0.05). The real-time PCR showed that bevacizumab had a stronger inhibitory effect on the expression of MMP-2 and MMP-9 mRNA at the concentration of 50 µg/ml and on the expression c-Met mRNA at the concentration of 10 µg/ml bevacizumabin the A549 cells. However bevacizumab at the concentration of 100 µg/ml showed a promoting effect on the expression of MMP-2, MMP-9 and c-Met mRNA (1.82 ± 0.31, 1.60 ± 0.25, 2.63 ± 0.48), significantly higher than that of the control group (1.00 ± 0.19, 1.00 ± 0.23, 1.00 ± 0.22, P<0.05). The expression of MMP-2, MMP-9 and c-Met mRNA and protein was inhibited by 10 µg/ml bevacizumab in a time-dependent manner. The Western blot assay showed that bevacizumab had a bi-directional effect on the expression of MMP-2 and c-Met proteins in the A549 cells: a promoting effect at 100 µg/ml and inhibitory effect on the expression of MMP-2 at 50 µg/ml bevacizumab, and inhibitory effect on the expression of c-Met protein at 10 µg/ml bevacizumab.</p><p><b>CONCLUSIONS</b>Our findings indicate that in a certain range of concentrations, bevacizumab has prominent inhibitory effect on the proliferation and invasion of A549 cells. However,over the concentration of 100 µg/ml, bevacizumab shows a weakening anti-invasion effect, even has a promoting effect on cell proliferation. This phenomenon may be related to the inhibiting effect on the expression of MMP-2 and c-Met proteins in a non-concentration-dependent manner by bevacizumab.</p>

Analysis on job stress assessment in BSL-3 laboratories / 中国比较医学杂志

Objective The staffs of biosafety level 3 laboratories (BSL-3) face with the stress of handling highly pathogenic microbs and special laboratory environment.The job stress may result in accidents in the laboratory as negative factor for the risk control.The research may provide support for the control of risk in biosafety laboratories.Methods In order to assess the job stress in the staff in BSL-3 laboratory, we modified “the Chinese simple job stress questionnaire”based on the theory of the JDC mode and ERI mode, and an investigation was carried out.The present study included the staffs (87 employees) from six BSL-3 laboratories located in five provinces ( Shanghai, Zhejiang, Jiangsu, Fujian and Wuhan) .Results Analysis of the data indicates that variables of age, working years, job duties, manipulating of animals, type of microorganisms and transmission route have a significant influence on the level of job stress in BSL-3 laboratory.Conclusion The BSL-3 laboratory staff in higher stress level have the characteristicses:20-39 years old, short work years, regular staff, operating on air-borne microbiology, manipulating of animals and operating on one more microbiology.

The molecular characteristics and virulence factor of Methicillin-resistant Staphylococcus aureus isolatedfrom pediatric patients / 中华传染病杂志

Objective To investigate the molecular characteristic,the virulence factors and antimicrobial resistance of Methicillin-resistant Staphylococcus aureus (MRSA) isolated from pediatric patients.Methods Ninety-eight non-duplicate strains of and 49 non-duplicate strains of Methicillinsusceptible Staphylococcus aureus (MSSA) isolated from the three children's hospitals in Shanghai in 2008 were investigated.Panton-valentine leukocidin (PVL) gene was detected by polymerase chain reaction (PCR).The genotypes of staphylococcal cassette chromosome mec (SCCmec) of the MRSA isolates were confirmed by multiplex PCR.The sequence type (ST) of each strain was determined by multilocus sequence typing (MLST),and the algorithm eBURST was used to identify groups of clonal complex (CC).The minimal inhibitory concentrations (MIC) of fourteen antibiotics for all isolates were determined by agar dilution method.Results Among 98 isolates of MRSA,the positive rate of PVL genes was 6.1％ (6/98).In contrast,the positive rate of PVL genes was 4.1％ (2/48) of the MSSA strains.Among 98 isolates of MRSA,4.1％ (4/98),23.5％ (23/98),53.0％ (52/98) and 15.3％ (15/98) of the strains harboured SCCmec types Ⅱ,Ⅲ,Ⅳ and Ⅴ,respectively. The remaining four isolates (4.1 ％) presented a unique SCCmec pattern that could not be classified to any known types by the employed typing assays.Combining the ST and SCCmec type,the predominant clones were ST59-SCCmec Ⅳ (30 strains) and ST239-SCCmec Ⅲ (23 strains),followed by ST5-SCCmecⅣ and ST1-SCCmecⅣ (8 strains for each clone),ST239-SCCmec Ⅴ (6 strains),ST88-SCCmecⅤ (5 strains),ST5 SCCmecⅡ (4 strains),ST59-SCCmec Ⅴ (3 strains),ST8-SCCmecⅣ and ST88-SCCmecⅣ (2 strains for each clone),ST22-SCCmecⅣ,ST910-SCCmecⅣ and S45-SCCmec Ⅴ (1 strain for each clone),eBURST analysis distributed the MRSA isolates into several CC.ST8 and ST239 belonged to ST8 CC,ST1 belonged to ST15 CC,ST910 belonged to ST 30 CC,ST59,ST5,ST88,ST45,ST22,ST9 and ST7 were the origin of their own CC.The results of MIC showed that the 67 strains of MRSA harboring SCCmec type Ⅳ or SCCmec type Ⅴ were more susceptible to various non-β-lactam antibiotics than 27 strains of MRSA harboring SCCmec type Ⅱ or SCCmec type Ⅲ,and no vancomycin-resistant strain was found.Conclusions In three children's hospitals in Shanghai,the PVL gene-positive rate of MRSA isolates is relatively low,SCCmec type Ⅳ and SCCmec type Ⅴ could spread among hospitals to cause a small scale epidemic and have a variety of ST.

Expression profiles of IL-10, TNF-a, and SOCS3 in placenta of pregnant women with intrahepatic cholestasis / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To detect the expression profiles of suppressor of cytokine signaling 3 (SOCS3), interleukin (IL)-10, and tumor necrosis factor-alpha (TNF-a) in the placenta of women with intrahepatic cholestasis of pregnancy (ICP) and determine the clinical significance of the differential expressions.</p><p><b>METHODS</b>Placentas were collected from 37 ICP gravidas who delivered through cesarean section at the First Teaching Hospital of Xingjiang Medical University from October 2010 to May 2011 and from 35 healthy pregnant women (controls). SOCS3, TNF-a, and IL-10 protein levels were detected by immunoblotting and the Envision immunohistochemical method.</p><p><b>RESULTS</b>TNF-a and IL-10 expression was detected in placentas of both groups, and was present mainly in the cytoplasm of trophoeytes. IL-10 expression was obviously lower in the ICP placentas than in the control placentas; meanwhile, TNF-a expression was obviously higher than in the control placentas (Z=-2.63, P less than 0.01). SOCS3 protein was significantly more abundant in the control placentas than in the ICP placentas. Furthermore, SOCS3 and IL-10 placental expressions were positively correlated (r=0.494, P less than 0.01), but there was a negative correlation between SOCS3 and TNF-a placental expressions (r=-0.472, P less than 0.01).</p><p><b>CONCLUSION</b>In ICP, an increase of the type 1 cytokine, TNF-a, is associated with decreases of the type 2 cytokine, IL-10, and of SOCS3, which may reduce the secretion of IL-10. Furthermore, SOCS3 may contribute to ICP pathogenesis by modulating the Th1/Th2 cytokine balance.</p>