Relationships among gut microbiota, plasma metabolites, and juvenile idiopathic arthritis: a mediation Mendelian randomization study.

Objective: The objective of this study is to investigate the causal relationship between gut microbiota and juvenile idiopathic arthritis, and to identify and quantify the potential role of plasma metabolites as mediators. Methods: Using summary-level data from genome-wide association studies, a two-sample Mendelian randomization was conducted involving 131 gut microbiota genus, 1,400 plasma metabolites, and juvenile idiopathic arthritis. Additionally, a two-step approach was employed to quantify the proportion of the effect of gut microbiota on juvenile idiopathic arthritis mediated by plasma metabolites. Effect estimation primarily utilized Inverse Variance Weighting, with further validation using Bayesian weighted Mendelian randomization. Results: In our MR analysis, a positive correlation was observed between Rikenellaceae and the risk of juvenile idiopathic arthritis, while Dorea showed a negative correlation with juvenile idiopathic arthritis risk. Mediation analysis indicated that Furaneol sulfate levels acted as a mediator between Dorea and juvenile idiopathic arthritis, with an indirect effect proportion of 19.94, 95% CI [8.86-31.03%]. Conclusion: Our study confirms a causal relationship between specific microbial genus and juvenile idiopathic arthritis, and computes the proportion of the effect mediated by plasma metabolites, offering novel insights for clinical interventions in juvenile idiopathic arthritis.

Pentraxin 3 exacerbates psoriasiform dermatitis through regulation of macrophage polarization.

OBJECTIVE: To elucidate the mechanism of Pentraxin 3 (PTX3) in the pathogenesis of psoriasiform dermatitis using Ptx3-knockout (Ptx3-KO) background mice. METHODS: An Imiquimod (IMQ)-induced murine psoriatic model was created using Ptx3-KO (Ptx3-/-) and wild-type (Ptx3+/+) mice. Skin lesion severity and expression of inflammatory mediators (IL-6 and TNFα) were assessed using PASI score and ELISA, respectively. Cutaneous tissues from the two mice groups were subjected to histological analyses, including HE staining, Masson staining, and Immunohistochemistry (IHC). The PTX3, iNOS, COX2, and Arg1 expressions were quantified and compared between the two groups. We used RNA-seq to clarify the underlying mechanisms of the disease. Flow cytometry was used to analyze systemic Th17 cell differentiation and macrophage polarization. RESULT: The psoriatic region exhibited a higher PTX3 expression than the normal cutaneous area. Moreover, PTX3 was upregulated in HaCaT cells post-TNFα stimulation. Upon IMQ stimulation, Ptx3-/- mice displayed a lower degree of the psoriasiform dermatitis phenotype compared to Ptx3+/+ mice. Consistent with the RNA-seq results, further experiments confirmed that compared to the wild-type group, the PTX3-KO group exhibited a generally lower IL-6, TNFα, iNOS, and COX2 expression and a contrasting trend in macrophage polarization. However, no significant difference in Th17 cell activation was observed between the two groups. CONCLUSIONS: This study revealed that PTX3 was upregulated in psoriatic skin tissues and TNFα-stimulated HaCaT cells. We also discovered that PTX3 deficiency in mice ameliorated the psoriasiform dermatitis phenotype upon IMQ stimulation. Mechanistically, PTX3 exacerbates psoriasiform dermatitis by regulating macrophage polarization rather than Th17 cell differentiation.

Aminopeptidase O Protein mediates the association between Lachnospiraceae and appendicular lean mass.

Objective: Investigating the causal relationship between Lachnospiraceae and Appendicular lean mass (ALM) and identifying and quantifying the role of Aminopeptidase O Protein (AOPEP) as a potential mediator. Methods: The summary statistics data of gut microbiota composition from the largest available genome-wide association study (GWAS) meta-analysis conducted by the MiBioGen Consortium (n = 13,266). Appendicular lean mass data were obtained from the UK-Biobank (n = 450,243). We conducted bidirectional two-sample Mendelian randomization (MR) analysis using summary-level data from GWAS to investigate the causal relationship between Lachnospiraceae and ALM. Additionally, we employed a drug-targeted MR approach to assess the causal relationship between AOPEP and ALM. Finally, a two-step MR was employed to quantitatively estimate the proportion of the effect of Lachnospiraceae on ALM that is mediated by AOPEP. Cochran's Q statistic was used to quantify heterogeneity among instrumental variable estimates. Results: In the MR analysis, it was found that an increase in genetically predicted Lachnospiraceae [OR = 1.031, 95% CI (1.011-1.051), P = 0.002] is associated with an increase in ALM. There is no strong evidence to suggest that genetically predicted ALM has an impact on Lachnospiraceae genus [OR = 1.437, 95% CI (0.785-2.269), P = 0.239]. The proportion of genetically predicted Lachnospiraceae mediated by AOPEP was 34.2% [95% CI (1.3%-67.1%)]. Conclusion: Our research reveals that increasing Lachnospiraceae abundance in the gut can directly enhance limb muscle mass and concurrently suppress AOPEP, consequently mitigating limb muscle loss. This supports the potential therapeutic modulation of gut microbiota for sarcopenia. Interventions such as drug treatments or microbiota transplantation, aimed at elevating Lachnospiraceae abundance and AOPEP inhibition, synergistically improve sarcopenia in the elderly, thereby enhancing the overall quality of life for older individuals.

A genome-wide analysis of the GRAS gene family in upland cotton and a functional study of the role of the GhGRAS55 gene in regulating early maturity in cotton.

The members of the GRAS gene family play important roles in regulating plant growth and development, but their functions in regulating early plant maturity traits are still unknown. In this study, we used a series of bioinformatics tools to identify GRAS gene family members and investigate the function of the gene family (GhGRAS55) using a genome-wide database of upland cotton samples. A total of 58 members of the GRAS gene family were identified and screened, which were distributed on 21 chromosomes within the whole cotton genome. The results of the phylogenetic analysis showed that the genes of upland cotton, island cotton, African cotton, Raymond cotton, and Arabidopsis were distributed in subfamilies I-VIII, although subfamily II did not contain any upland cotton or Arabidopsis GRAS family members. The structures and other characteristics of the genes in this family were clarified using bioinformatics technology. The transcriptomic sequencing results for early and late maturing cotton species showed that the expression of most GRAS family genes, such as GhGRAS10, GhGRAS5511, and GhGRAS55, was lower in early maturing species than late maturing species. We also found that cotton plants with GhGRAS55 genes that were silenced by virus-induced gene silencing (VIGS) technology showed early bud emergence phenotypes, so it could be speculated that the GhGRAS55 gene has the function of regulating early maturity in cotton.

The Valuable Prognostic Impact of Regional Lymph Node Removed on Outcomes for IIIA N0 NSCLC Patients.

Background: Regional lymph nodes (RLNs) removed combined with surgery is a standard option for patients at stage I to IIIA NSCLC. The objective of the study is to clarify the effect of removing different number of RLNs on survival outcomes for patients at stage IIIA N0 NSCLC. Methods: Patients at stage IIIA N0 NSCLC from 2004 to 2015 were identified from Surveillance, Epidemiology, and End Results (SEER) database. Prior propensity score method (PSM), survival time was compared among different number (0, 1-3 and ≥4) of RLNs removed groups. After PSM, lung cancer-specific survival (LCSS) and overall survival (OS) were compared. Kaplan-Meier analysis and Cox regression analyses were used to clarify the impact of the factors on the prognosis with hazard ratio (HR) and 95% confidence interval (CI). Results: A total of 11,583 patients at stage IIIA N0 NSCLC were included. Prior PSM, survival indicators including 1-year mortality rate, 5-year mortality rate, median survival time (MDST) and mean survival time (MST) from good to bad were all: ≥4, 1-3 and none RLNs removed group. After PSM, Kaplan-Meier survival analyses and univariate Cox regression analyses on OS and LCSS revealed a statistically significance on survival curve (P<0.001) between each two of the three groups (none, 1-3 and ≥4 RLNs removed group). Multivariable Cox regression analyses on OS and LCSS showed an independent association of RLNs removed with higher OS (HR, 0.275; 95% CI, 0.259-0.291; P<0.001) and LCSS (HR, 0.239; 95% CI, 0.224-0.256; P<0.001) compared with none RLN removed and no statistical difference with OS (HR, 1.118; 95% CI, 0.983-1.271; P=0.088) and LCSS (HR, 1.107; 95% CI, 0.954-1.284; P=0.179) between 1-3 RLNs removed and ≥4 RLNs removed. Conclusions: Removing RLNs was beneficial to survival outcomes of patients at stage IIIA N0 NSCLC. Compared with 1-3 RLNs removed, ≥4 RLNs removed could bring a better survival time but not an independent prognostic factor (P>0.05).

Analysis of Cognition, Protection, Psychological, and Job-search Intentions Among Medical and Nonmedical College Students During COVID-19 Epidemic.

Context: Since December 2019, medical practitioners discovered a novel coronavirus causing an acute respiratory-tract infection in some hospitals in Wuhan, Hubei Province. COVID-19 has spread globally, making it an epidemic worldwide at present. Understanding the mental-health responses of college students to COVID-19 can help a school staff to better guide students seeking education. Objective: The study aimed to explore the differences between nonmedical and medical college students during the COVID-19 epidemic in their cognitive interest about the disease, preventive behaviors, psychological effects, and job-search intentions, hoping to provide more targeted measures for virus-coping education for college students. Design: The research team conducted a cross-sectional study, using an anonymous online questionnaire. Setting: The study took place at Shanghai, China. Participants: Participants were 1648 college students studying different specialties in various provinces of China, 485 nonmedical students and 1163 medical students. Outcome Measures: The survey's questions covered the respondents': (1) general demographic characteristics, (2) cognitive interest and knowledge about COVID-19 and its infectiousness as well as efforts at active learning about infectious diseases and viruses, (3) awareness of precautionary behaviors against COVID-19, (4) effects on mental health, and (5) effects on job-search intentions. The research team used descriptive statistics and Chi-square tests to analyze the survey data. Results: Among nonmedical students: (1) 297 participants (61.2%) were interested in learning about COVID-19, (2) 321 participants (66.2%) took the initiative to learn about the virus, (3) 301 participants (62.1%) took the initiative to learn about infectious disease, and (4) 151 participants (31.1%) watched medical-themed movies or TV series about COVID-19. Among medical students, the corresponding proportions were 772 participants (66.4%), 855 participants (73.5%), 791 participants (68.1%), and 791 participants (68.1%), respectively. Among nonmedical students, 223 participants (46.0%) had N95 masks available, 429 participants (88.5%) had disinfectant supplies available, 271 participants (55.9%) wore goggles in public places, 75 participants (15.5%) chose public transportation, and 77 participants (15.9%) were exposed to public places in the week prior to the survey. Among medical students, the corresponding proportions were 470 participants (40.4%), 935 participants (80.4%), 575 participants (49.4%), 243 participants (20.9%), and 297 participants (25.5%), respectively. Furthermore, COVID-19 had a stronger effect on medical students' psychology and job-search ambitions. Conclusions: The news about COVID-19 piqued the interest of medical students. Nonmedical students had stronger protective behavior than medical students. The COVID-19 outbreak had a significant influence on medical students' lives, studies, and moods. In addition, COVID-19 had a greater impact on the job-search intentions of medical students.

Application of Multi-Criteria Decision-Making Analysis to Rural Spatial Sustainability Evaluation: A Systematic Review.

The rational allocation of spatial resources is an important factor to ensure the sustainable development of rural areas, and effective pre-emptive spatial evaluation is the prerequisite for identifying the predicament of rural resource allocation. Multi-criteria decision-making analysis has advantages in solving multi-attribute and multi-objective decision-making problems, and has been used in sustainability evaluation research in various disciplines in recent years. Previous studies have proved the value of spatial evaluation using multi-criteria decision analysis in guiding rural incremental development and inventory updates, but systematic reviews of the previous literature from a multidisciplinary perspective and studies of the implementation steps of the evaluation framework are lacking. In the current paper, the research is reviewed from the two levels of quantitative statistics and research content, and through vertical and horizontal comparisons based on three common operating procedures: standard formulation, weight distribution, and ranking and verification. Through the results, the application status and characteristics of the MCDA method in related research are determined, and five research foci in the future are proposed.

Highly Robust de Novo Full-Length Protein Sequencing.

Accurate full-length sequencing of a purified unknown protein is still challenging nowadays due to the error-prone mass-spectrometry (MS)-based methods. De novo identified peptide sequence largely contain errors, undermining the accuracy of assembly. Bias on the detectability of the peptides also makes low-coverage regions, resulting in gaps. Although recent advances on multi-enzyme hydrolysis and algorithms showed complete assembly of full-length protein sequences in a few examples, the robustness in practical application is still to be improved. Here, inspired by genome assembly strategies, we demonstrate a contig-scaffolding strategy to assemble protein sequences with high robustness and accuracy. This strategy integrates multiple unspecific hydrolysis methods to minimize the bias in the hydrolysis process. After de novo identification of the peptides, our assembly algorithm, named Multiple Contigs & Scaffolding (MuCS), assembles the peptide sequences in a multistep, i.e., contig-scaffold manner, with error correction in each step. MS data from different hydrolysis experiments complement each other for robust contig extension and error correction. We demonstrated that our strategy on three proteins and three replications all reached 100% coverage (except one with 98.85%) and 98.69-100% accuracy. It can also efficiently deal with the membrane protein, although the transmembrane region was missing due to the limitation of the MS. The three replicates reached 88.85-92.57% coverage and 97.57-100% accuracy. In sum, we provided a practical, robust, and accurate solution for full-length protein sequencing. The MuCS software is available at http://chi-biotech.com/mucs/.

V367F Mutation in SARS-CoV-2 Spike RBD Emerging during the Early Transmission Phase Enhances Viral Infectivity through Increased Human ACE2 Receptor Binding Affinity.

The current pandemic of COVID-19 is caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 spike protein receptor-binding domain (RBD) is the critical determinant of viral tropism and infectivity. To investigate whether naturally occurring RBD mutations during the early transmission phase have altered the receptor binding affinity and infectivity, we first analyzed in silico the binding dynamics between SARS-CoV-2 RBD mutants and the human angiotensin-converting enzyme 2 (ACE2) receptor. Among 32,123 genomes of SARS-CoV-2 isolates (December 2019 through March 2020), 302 nonsynonymous RBD mutants were identified and clustered into 96 mutant types. The six dominant mutations were analyzed applying molecular dynamics simulations (MDS). The mutant type V367F continuously circulating worldwide displayed higher binding affinity to human ACE2 due to the enhanced structural stabilization of the RBD beta-sheet scaffold. The MDS also indicated that it would be difficult for bat SARS-like CoV to infect humans. However, the pangolin CoV is potentially infectious to humans. The increased infectivity of V367 mutants was further validated by performing receptor-ligand binding enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance, and pseudotyped virus assays. Phylogenetic analysis of the genomes of V367F mutants showed that during the early transmission phase, most V367F mutants clustered more closely with the SARS-CoV-2 prototype strain than the dual-mutation variants (V367F+D614G), which may derivate from recombination. The analysis of critical RBD mutations provides further insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin under negative selection pressure and supports the continuing surveillance of spike mutations to aid in the development of new COVID-19 drugs and vaccines. IMPORTANCE A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused the pandemic of COVID-19. The origin of SARS-CoV-2 was associated with zoonotic infections. The spike protein receptor-binding domain (RBD) is identified as the critical determinant of viral tropism and infectivity. Thus, whether mutations in the RBD of the circulating SARS-CoV-2 isolates have altered the receptor binding affinity and made them more infectious has been the research hot spot. Given that SARS-CoV-2 is a novel coronavirus, the significance of our research is in identifying and validating the RBD mutant types emerging during the early transmission phase and increasing human angiotensin-converting enzyme 2 (ACE2) receptor binding affinity and infectivity. Our study provides insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin. The continuing surveillance of RBD mutations with increased human ACE2 affinity in human or other animals is critical to the development of new COVID-19 drugs and vaccines against these variants during the sustained COVID-19 pandemic.

Evaluation of the efficiency of peptide receptor radionuclide therapy in patients with metastatic prostate carcinoma: A protocol for systematic review and meta-analysis.

BACKGROUND: Metastatic prostate carcinoma has poor prognoses with a median survival period ranging from 2 to 5 years with existing therapeutic challenges. Currently, peptide receptor radionuclide therapy is permitted as a treatment method for metastatic prostate carcinoma patients. Therefore, it is crucial to comprehend the efficiency and safety of peptide receptor radionuclide therapy among this patient population. This study aims to analyse the efficacy of peptide receptor radionuclide therapy when used to treat metastatic prostate carcinoma patients. METHODS: This research will perform a methodological search in the following electronic databases to find related randomized controlled trials: Cochrane Library, EMBASE, PubMed, Web of Science, Scopus, China National Knowledge Infrastructure (CNKI), WanFang database, and Chinese BioMedical Literature. All the databases are searched from their inauguration till November 2020. Two independent authors will screen and select literature for review. The two authors will independently utilize the Cochrane Risk of Bias tool to assess the bias risk in studies. This study also plans to conduct subgroup and sensitivity analyses to evaluate the robustness in the results. Statistical analyses will be conducted with the RevMan 5.3 software. RESULTS: A high-quality synthesis of existing evidence related to peptide receptor radionuclide therapy in the treatment of metastatic prostate carcinoma will be presented in this study. CONCLUSION: Our findings will provide evidence to judge whether peptide receptor radionuclide treatment is efficient for metastatic prostate carcinoma patients. ETHICS AND DISSEMINATION: An ethics approval is not required because the data of the present study are primarily obtained from published studies.OSF registration number: December 1, 2020.osf.io/3psx7. (https://osf.io/3psx7/).

Transformation and functional verification of Cry5Aa in cotton.

Most of the cotton bollworm-resistant genes applied in cotton are more than 20 years and they all belong to Cry1Ab/c family, but the insect-resistant effects of Cry5Aa on cotton were rarely reported. The possible risk of resistance is increasing. The study synthesized a novel bollworm-resistant gene Cry5Aa artificially based on preferences of cotton codon. The new gene was transferred to cotton through the method of pollen tube pathway. The transgenic strains were identified by kanamycin test in field and laboratory PCR analysis. Meanwhile, an insect resistance test was conducted by artificial bollworm feeding with transgenic leaves and GK19 was used as a control in this study. Results showed that rate of positive transgenic strains with kanamycin resistance in the first generation (T1), the second generation (T2) and the third generation (T3) respectively were 7.76%, 73.1% and 95.5%. However, PCR analysis showed that the positive strain rate in T1, T2 and T3 were 2.35%, 55.8% and 94.5%, respectively. The resistant assay of cotton bollworm showed that the mortality rate of the second, third and fourth instar larva feed by the transgenic cotton leaves, were 85.42%, 73.35% and 62.79%, respectively. There was a significant difference between transgenic plant of Cry5Aa and GK19 in insect resistance. Finally, we also conducted the further analysis of gene expression patterns, gene flow and the effect on non-target pest in the study. The results showed that Cry5Aa gene had less environmental impact, and Cry5Aa has been transferred successfully and expressed stably in cotton. Therefore, the novel bollworm resistance gene can partially replace the current insect-resistance gene of Lepidoptera insects.

Temperature dependence of the SARS-CoV-2 affinity to human ACE2 determines COVID-19 progression and clinical outcome.

The SARS-CoV-2 virus and its homolog SARS-CoV penetrate human cells by binding of viral spike protein and human angiotensin converting enzyme II (ACE2). SARS-CoV causes high fever in almost all patients, while SARS-CoV-2 does not. Moreover, analysis of the clinical data revealed that the higher body temperature is a protective factor in COVID-19 patients, making us to hypothesize a temperature-dependent binding affinity of SARS-CoV-2 to human ACE2 receptor. In this study, our molecular dynamics simulation and protein surface plasmon resonance cohesively proved the SARS-CoV-2-ACE2 binding was less affinitive and stable under 40 °C (~18 nM) than the optimum temperature 37 °C (6.2 nM), while SARS-CoV-ACE2 binding was not (6.4 nM vs. 8.5 nM), which evidenced the temperature-dependent affinity and explained that higher temperature is related to better clinical outcome. The decreased infection at higher temperature was also validated by pseudovirus entry assay using Vero and Caco-2 cells. We also demonstrated the structural basis of the distinct temperature-dependence of the two coronaviruses. Furthermore, the meta-analysis revealed a milder inflammatory response happened in the early stage of COVID-19, which explained the low fever tendency of COVID-19 and indicated the co-evolution of the viral protein structure and the inflammatory response. The temperature dependence of the binding affinity also indicated that higher body temperature at early stages might be beneficial to the COVID-19 patients.

Serum level of fetuin B is associated with osteoporosis: a 4-year prospective study in China.

PURPOSE: As a novel hepatokine, fetuin B involves in various functions of energy metabolism. Recent advance reveals a complex interaction between bone and liver via the secretion of hepatokines. The association between serum fetuin B and osteoporosis was evaluated in a 4-year hospital-based prospective study of 1,370 Chinese postmenopausal women. METHODS: Bone mineral densities (BMDs) were obtained on femoral neck and lumbar spines by dual energy X-ray absorptiometry. Serum fetuin B level was tested by enzyme-linked immunosorbent assay. RESULTS: Of the 1,370 participants in the baseline study (2012), 650 subjects were included in the 4-year follow-up study (2016). Serum fetuin B level presented higher in subjects with osteoporosis (106.7 ± 17.6 µg/ml) than it in controls (86.3 ± 17.5 µg/ml) (P < 0.001). Meanwhile, fetuin B positively correlated with triglycerides (r = 0.227, P = 0.001), femoral BMD (r = -0.426, P < 0.001) and lumbar BMD (r = -0.332, P < 0.001). At the 4-year follow-up, 116 subjects had developed osteoporosis. Serum fetuin B concentration was significantly higher in subjects who developed (P < 0.001). The osteoporosis incidence increased from Q1 9.9%, Q2 14.7%, and Q3 17.8% to Q4 30.2% (P for trend < 0.001), among the quartiles of baseline fetuin B. A higher fetuin B baseline level was linked to the incidence of osteoporosis (adjusted OR = 1.179, 95% CI [1.119 - 1.243], P = 0.009). CONCLUSION: Serum fetuin B levels increased with the development of osteoporosis.

Simplified recovery of enzymes and nutrients in sweet potato wastewater and preparing health black tea and theaflavins with scrap tea.

The industry discards generous organic wastewater in sweet potato starch factory and scrap tea in tea production. A simplified procedure to recover all biochemicals from the wastewater of sweet potato starch factory and use them to make health black tea and theaflavins from scrap green tea was developed. The sweet potato wastewater was sequentially treated by isoelectric precipitation, ultrafiltration and nanofiltration to recover polyphenol oxidase (PPO), ß-amylase, and small molecular fractions, respectively. The PPO fraction can effectively transform green tea extracts into black tea with high content of theaflavins through the optimized fed-batch feeding fermentation. The PPO transformed black tea with sporamins can be used to make health black tea, or make theaflavins by fractionation with ethyl acetate. This work provides a resource- and environment-friendly approach for economically utilizing the sweet potato wastewater and the scrap tea, and making biochemical, nutrient and health products.

Graphics processing unit-based alignment of protein interaction networks.

Network alignment is an important bridge to understanding human protein-protein interactions (PPIs) and functions through model organisms. However, the underlying subgraph isomorphism problem complicates and increases the time required to align protein interaction networks (PINs). Parallel computing technology is an effective solution to the challenge of aligning large-scale networks via sequential computing. In this study, the typical Hungarian-Greedy Algorithm (HGA) is used as an example for PIN alignment. The authors propose a HGA with 2-nearest neighbours (HGA-2N) and implement its graphics processing unit (GPU) acceleration. Numerical experiments demonstrate that HGA-2N can find alignments that are close to those found by HGA while dramatically reducing computing time. The GPU implementation of HGA-2N optimises the parallel pattern, computing mode and storage mode and it improves the computing time ratio between the CPU and GPU compared with HGA when large-scale networks are considered. By using HGA-2N in GPUs, conserved PPIs can be observed, and potential PPIs can be predicted. Among the predictions based on 25 common Gene Ontology terms, 42.8% can be found in the Human Protein Reference Database. Furthermore, a new method of reconstructing phylogenetic trees is introduced, which shows the same relationships among five herpes viruses that are obtained using other methods.

[Expression of HCN4 protein in ventricular outflow tract of rabbit with idiopathic ventricular tachycardia].

OBJECTIVE: To confirm the existence of purkinje fibers in rabbit outflow tract tissue and explore the role of Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel 4 (HCN4) protein in idiopathic ventricular tachycardia. METHODS: A total of ten New Zealand white rabbits were randomly selected to observe whether there were pukinje fibers in outflow tract by the methods of HE staining and immunohistochemical detection of midsize neurofilament (NF-M). Forty rabbits were randomly divided into four groups: normal control group (SO), ventricular tachycardia group (VT), ventricular tachycardia+ esmolol intervention group (VT+ ESM) and ventricular tachycardia+ ivabradine intervention group (VT+ IVA). Immunohistochemistry was used to detect the expression of HCN4 protein in ventricular outflow tract; the required output voltage amplitude was recorded when ventricular tachycardia was induced; the times and duration of spontaneous ventricular tachycardia when stimulation stopped were also recorded for each group. RESULTS: (1)Purkinje fibers existed in the myocardial tissue of rabbit outflow tract. (2)HCN4 protein expression significantly increased in VT group compared with SO group (left ventricular: 97.6 ± 16.7 vs 29.0 ± 8.0, P<0.01; right ventricular: 92.7 ± 12.3 vs 26.0 ± 10.8, P<0.01), the expression of HCN4 protein obviously reduced in VT+ IVA group compared with VT group (left ventricular: 32.0 ± 9.4 vs 97.6 ± 16.7, P<0.01; right ventricular: 30.8 ± 12.4 vs 92.7 ± 12.3, P<0.01). (3)The output voltage amplitude required to induce the desired ventricular tachycardia in VT+ ESM group and VT+ IVA group were higher than the VT group, under the same high frequency stimulation (P<0.01); the times and duration of spontaneous ventricular tachycardia in VT+ ESM group and VT+ IVA group significantly reduced when the stimulation stopped, compared with the VT group (both P<0.01). CONCLUSIONS: (1)Purkinje fibers exist in ventricular outflow tract, which may be the histological origin of the ventricular tachycardia. (2)HCN4 protein is up-regulated in ventricular outflow tract when ventricular tachycardia occurs. (3)Esmolol and ivabradine can prevent and reduce the occurrence of ventricular tachycardia, and as the specific inhibitor of the HCN channel, the effect of ivabradine is more obvious.

A novel Pseudomonas aeruginosa strain with an oprD mutation in relation to a nosocomial respiratory infection outbreak in an intensive care unit.

Seven imipenem-resistant Pseudomonas aeruginosa isolates were recovered from the sputum samples of pneumonia patients in southwestern China. They had identical antibiotic resistance patterns and indistinguishable pulsed-field gel electrophoresis profiles. Nucleotide sequence analysis revealed a 4-bp (AGTC) insertion in the oprD gene, resulting in a frameshift in the cognate open reading frame. These isolates became imipenem susceptible when the chromosomal oprD lesion was complemented, indicating that the 4-bp insertion in the oprD gene resulted in imipenem resistance.

The association between genetic damage in peripheral blood lymphocytes and polymorphisms of three glutathione S-transferases in Chinese workers exposed to 1,3-butadiene.

1,3-Butadiene (BD) has been classified as a human carcinogen, group I; however, the relationship between polymorphisms of glutathione S-transferases that metabolize BD and chromosomal damage is not clear. The present study used sister chromatid exchange (SCE) and cytokinesis-block micronucleus (CBMN) assays to detect chromosomal damage in peripheral lymphocytes of 44 BD-exposed workers and 39 non-exposed healthy controls. PCR and PCR-RFLP were employed to detect three known glutathione S-transferase polymorphisms GSTT1, GSTM1, and GSTP1 (Ile105Val). The data demonstrated that the micronucleus (CBMN) frequency in BD-exposed workers was significantly higher than that in controls (frequency ratio (FR)=1.48, 95% CI: 1.14-1.91, P<0.01), and the CBMN frequency was higher in workers exposed to higher cumulative BD levels (FR=1.70, 95% CI: 1.28-2.27, P<0.01). However, differences in SCE frequency were not observed (FR=1.14, 95% CI: 0.81-1.61, P>0.05). Among exposed workers, chromosomal damage was related to BD exposure levels (FR=1.35, 95% CI: 1.02-1.80, P<0.05); age, older workers exhibited higher MN frequencies than younger workers (FR=1.45, 95% CI: 1.14-1.84, P<0.05); and years of work, those with more years of work exhibited higher MN frequencies than those with fewer years (FR=1.40, 95% CI: 1.10-1.77, P<0.05). Multivariate Poisson regression analysis showed that those who carried GSTM1 (-) (FR=1.48, 95% CI: 1.14-1.92) or GSTT1 (-) (FR=1.42, 95% CI: 1.10-1.83) genotypes, and especially those who carried both (FR=2.10, 95% CI: 1.43-3.09) exhibited significantly higher MN frequencies than those carrying GSTM1 (+), GSTT1 (+) genotypes or their combination. The GSTP1 Val genotype did not affect MN frequency (P>0.05). Our results suggested that higher levels of BD exposure in the workplace resulted in increased chromosomal damage, and that polymorphisms in GSTT1 and GSTM1 genes might modulate the genotoxic effects of BD exposure. Furthermore, the GSTT1 and GSTM1 polymorphisms exhibited an additive effect. Finally, urinary DHBMA was found to provide a biomarker that correlated with airborne BD levels.

Itch E3 ubiquitin ligase regulates large tumor suppressor 1 stability [corrected].

The large tumor suppressor 1 (LATS1) is a serine/threonine kinase and tumor suppressor found down-regulated in a broad spectrum of human cancers. LATS1 is a central player of the emerging Hippo-LATS suppressor pathway, which plays important roles in cell proliferation, apoptosis, and stem cell differentiation. Despite the ample data supporting a role for LATS1 in tumor suppression, how LATS1 is regulated at the molecular level remains largely unknown. In this study, we have identified Itch, a HECT class E3 ubiquitin ligase, as a unique binding partner of LATS1. Itch can complex with LATS1 both in vitro and in vivo through the PPxY motifs of LATS1 and the WW domains of Itch. Significantly, we found that overexpression of Itch promoted LATS1 degradation by polyubiquitination through the 26S proteasome pathway. On the other hand, knockdown of endogenous Itch by shRNAs provoked stabilization of endogenous LATS1 proteins. Finally, through several functional assays, we also revealed that change of Itch abundance alone is sufficient for altering LATS1-mediated downstream signaling, negative regulation of cell proliferation, and induction of apoptosis. Taking these data together, our study identifies E3 ubiquitin ligase Itch as a unique negative regulator of LATS1 and presents a possibility of targeting LATS1/Itch interaction as a therapeutic strategy in cancer.