Search

Klebsiella pneumoniae (K. pneumoniae) is a frequent pathogen causing nosocomial infections and outbreaks. We developed a multiple cross displacement amplification (MCDA) assay for the detection of K. pneumoniae, which can get the positive results within 40 minutes’ isothermal amplification. Gold-nanoparticle lateral flow biosensor (LFB) and colorimetric indicators were used for the rapid readouts of MCDA amplification. The detection limit of this assay was 100 fg per reaction at 65°C, which was confirmed to be the optimal amplification temperature according to the real time turbidimeters. For specificity, all of the 30 clinical-source K. pneumoniae strains were positive for the MCDA, and all of the non-K. pneumoniae strains belonging to 31 different species were negative for this MCDA assay. To evaluate the practical applicability of this method, we assessed its detection limit for K. pneumoniae strains in sputum samples (24 CFU per reaction), and DNA templates of 100 sputum samples further underwent the MCDA-LFB tests. All of the sputum samples being positive for K. pneumoniae (30/100) with the culture method were successfully identified with the MCDA assay, the detection power of which was higher than that of polymerase chain reaction (PCR) (25/100). Thus, the MCDA test for K. pneumoniae combined with the gold nanoparticle LFB as the results readout scheme, are simple, specific, and sensitive methods for the rapid diagnosis of K. pneumoniae in clinical samples. [ABSTRACT FROM AUTHOR]

Rapid repair of vascular injury is an important prognostic factor for electrical burns. This repair is achieved mainly via stromal cell-derived factor (SDF)-1α promoting the mobilization, chemotaxis, homing, and targeted differentiation of bone marrow mesenchymal stem cells (BMSCs) into endothelial cells. Forming a concentration gradient from the site of local damage in the circulation is essential to the role of SDF-1α. In a previous study, we developed reactive oxygen species (ROS)-sensitive PPADT nanoparticles containing SDF-1α that could degrade in response to high concentration of ROS in tissue lesions, achieving the goal of targeted SDF-1α release. In the current study, a rat vascular injury model of electrical burns was used to evaluate the effects of targeted release of SDF-1α using PPADT nanoparticles on the chemotaxis of BMSCs and the repair of vascular injury. Continuous exposure to 220 V for 6 s could damage rat vascular endothelial cells, strip off the inner layer, significantly elevate the local level of ROS, and decrease the level of SDF-1α. After injection of Cy5-labeled SDF-1α-PPADT nanoparticles, the distribution of Cy5 fluorescence suggested that SDF-1α was distributed primarily at the injury site, and the local SDF-1α levels increased significantly. Seven days after injury with nanoparticles injection, aggregation of exogenous green fluorescent protein-labeled BMSCs at the injury site was observed. Ten days after injury, the endothelial cell arrangement was better organized and continuous, with relatively intact vascular morphology and more blood vessels. These results showed that SDF-1α-PPADT nanoparticles targeted the SDF-1α release at the site of injury, directing BMSC chemotaxis and homing, thereby promoting vascular repair in response to electrical burns. [ABSTRACT FROM AUTHOR]

Luman (also known as LZIP or CREB3) is a transcription factor and a member of the cAMP responsive element-binding (CREB) family proteins. Although Luman has been detected in apoptotic granulosa cells and disorganized atretic bodies, the physiological function of Luman in follicular development has not been reported. Our objective is to determine the role of Luman in folliculogenesis by knocking down Luman expression in mouse GCs (granulosa cells) using shRNA. Luman expression was successfully knocked down in mouse GCs at the mRNA and protein level, as confirmed by real-time quantitative PCR, western blot and immunofluorescence staining, respectively. Knockdown of Luman significantly decreased the concentrations of estradiol (E2) and progesterone (P4) in cell culture medium. Furthermore, Luman knockdown promoted cell proliferation but had no effect on cell apoptosis. To elucidate the regulatory mechanism underlying the effects of Luman knockdown on steroid synthesis and cell cycle, we measured the mRNA and protein expression levels of several related genes. The expression of Star, Cyp19a1, and Cyp1b1, which encode steroidogenic enzymes, was down-regulated, while that of Cyp11a1 and Runx2, which also encode steroidogenic enzymes, was up-regulated. The expression of the cell cycle factors Cyclin A1, Cyclin B1, Cyclin D2, and Cyclin E was significantly up-regulated. Among apoptosis-related genes, only Bcl-2 was down-regulated, while Caspase 3, Bax and p53 were not significantly affected, suggesting that Luman knockdown may regulate cell cycle activity and hormone secretion at the transcriptional and translational level in mouse GCs. The expression of two important genes associated with folliculogenesis in mouse GCs, Has2 and Ptgs2, were also significantly altered by Luman knockdown. In conclusion, the findings of this study indicate that Luman regulates mouse GCs modulation of steroid synthesis, cell cycle activity and other regulators of folliculogenesis. [ABSTRACT FROM AUTHOR]

IκBβis an inhibitor of nuclear factor kappa B(NF-κB) and participates in the cardiac response to sepsis. However, the role of the hypo-phosphorylated form of IκBβ at Ser313, which can be detected during sepsis, is unknown. Here, we examined the effects of IκBβ with a mutation at Ser313→Ala313 on cardiac damage induced by sepsis. Transgenic (Tg) mice were generated to overexpress IκBβ, in which Ser-313 is replaced with alanine ubiquitously, in order to mimic the hypo-phosphorylated form of IκBβ. Survival analysis showed that Tg mice exhibited decreased inflammatory cytokine levels and decreased rates of mortality in comparison to wild type (WT) mice, after sepsis in a cecal-ligation and puncture model (CLP). Compared to WT septic mice, sepsis in Tg mice resulted in improved cardiac functions, lower levels of troponin I and decreased rates of cardiomyocyte apoptosis, compared to WT mice. The increased formation of autophagicvacuoles detected with electron microscopy demonstrated the enhancement of cardiac autophagy. This phenomenon was further confirmed by the differential expression of genes related to autophagy, such as LC3, Atg5, Beclin-1, and p62. The increased expression of Cathepsin L(Ctsl), a specific marker for mitochondrial stress response, may be associated with the beneficial effects of the hypo-phosphorylated form of IκBβ. Our observations suggest that the hypo-phosphorylated form of IκBβ at Ser313 is beneficial to the heart in sepsis through inhibition of apoptosisand enhancement of autophagy in mutated IκBβ transgenic mice. [ABSTRACT FROM AUTHOR]

Diet has been shown to have a critical influence on gut bacteria and host health, and high levels of red meat in diet have been shown to increase colonic DNA damage and thus be harmful to gut health. However, previous studies focused more on the effects of meat than of meat proteins. In order to investigate whether intake of meat proteins affects the composition and metabolic activities of gut microbiota, feces were collected from growing rats that were fed with either meat proteins (from beef, pork or fish) or non-meat proteins (casein or soy) for 14 days. The resulting composition of gut microbiota was profiled by sequencing the V4-V5 region of the 16S ribosomal RNA genes and the short chain fatty acids (SCFAs) were analyzed using gas chromatography. The composition of gut microbiota and SCFA levels were significantly different between the five diet groups. At a recommended dose of 20% protein in the diet, meat protein-fed rats had a higher relative abundance of the beneficial genus Lactobacillus, but lower levels of SCFAs and SCFA-producing bacteria including Fusobacterium, Bacteroides and Prevotella, compared with the soy protein-fed group. Further work is needed on the regulatory pathways linking dietary protein intake to gut microbiota. [ABSTRACT FROM AUTHOR]

The diamagnetic levitation as a novel ground-based model for simulating a reduced gravity environment has recently been applied in life science research. In this study a specially designed superconducting magnet with a large gradient high magnetic field (LG-HMF), which can provide three apparent gravity levels (μ-g, 1-g, and 2-g), was used to simulate a space-like gravity environment. Osteocyte, as the most important mechanosensor in bone, takes a pivotal position in mediating the mechano-induced bone remodeling. In this study, the effects of LG-HMF on gene expression profiling of osteocyte-like cell line MLO-Y4 were investigated by Affymetrix DNA microarray. LG-HMF affected osteocyte gene expression profiling. Differentially expressed genes (DEGs) and data mining were further analyzed by using bioinfomatic tools, such as DAVID, iReport. 12 energy metabolism related genes (PFKL, AK4, ALDOC, COX7A1, STC1, ADM, CA9, CA12, P4HA1, APLN, GPR35 and GPR84) were further confirmed by real-time PCR. An integrated gene interaction network of 12 DEGs was constructed. Bio-data mining showed that genes involved in glucose metabolic process and apoptosis changed notablly. Our results demostrated that LG-HMF affected the expression of energy metabolism related genes in osteocyte. The identification of sensitive genes to special environments may provide some potential targets for preventing and treating bone loss or osteoporosis. [ABSTRACT FROM AUTHOR]

Study Design: Meta-analysis. Background: Bilateral pedicle screw fixation (PS) after lumbar interbody fusion is a widely accepted method of managing various spinal diseases. Recently, unilateral PS fixation has been reported as effective as bilateral PS fixation. This meta-analysis aimed to comparatively assess the efficacy and safety of unilateral PS fixation and bilateral PS fixation in the minimally invasive (MIS) lumbar interbody fusion for one-level degenerative lumbar spine disease. Methods: MEDLINE/PubMed, EMBASE, BIOSIS Previews, and Cochrane Library were searched through March 30, 2014. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on unilateral versus bilateral PS fixation in MIS lumbar interbody fusion that met the inclusion criteria and the methodological quality standard were retrieved and reviewed. Data on participant characteristics, interventions, follow-up period, and outcomes were extracted from the included studies and analyzed by Review Manager 5.2. Results: Six studies (5 RCTs and 1 CCT) involving 298 patients were selected. There were no significant differences between unilateral and bilateral PS fixation procedures in fusion rate, complications, visual analogue score (VAS) for leg pain, VAS for back pain, Oswestry disability index (ODI). Both fixation procedures had similar length of hospital stay (MD = 0.38, 95% CI = −0.83 to 1.58; P = 0.54). In contrast, bilateral PS fixation was associated with significantly more intra-operative blood loss (P = 0.002) and significantly longer operation time (P = 0.02) as compared with unilateral PS fixation. Conclusions: Unilateral PS fixation appears as effective and safe as bilateral PS fixation in MIS lumbar interbody fusion but requires less operative time and causes less blood loss, thus offering a simple alternative approach for one-level lumbar degenerative disease. [ABSTRACT FROM AUTHOR]

Objective: Adiponectin receptor 1 (encoded by ADIPOR1) is one of the major adiponectin receptors, and plays an important role in glucose and lipid metabolism. However, few studies have reported simultaneous associations between ADIPOR1 variants and type 2 diabetes (T2D), coronary artery disease (CAD) and T2D with CAD. Based on the “common soil” hypothesis, we investigated whether ADIPOR1 polymorphisms contributed to the etiology of T2D, CAD, or T2D with CAD in a Northern Han Chinese population. Methods: Our multi-disease comparison study enrolled 657 subjects, including 165 with T2D, 173 with CAD, 174 with both T2D and CAD (T2D+CAD), and 145 local healthy controls. Six ADIPOR1 single nucleotide polymorphisms (SNPs) were genotyped and their association with disease risk was analyzed. Results: Multi-case-control comparison identified two ADIPOR1 variants: rs3737884-G, which was simultaneously associated with an increased risk of T2D, CAD, and T2D+CAD (P-value range, 9.80×10−5−6.30×10−4; odds ratio (OR) range: 1.96–2.42) and 16850797-C, which was separately associated with T2D and T2D+CAD (P-value range: 0.007–0.014; OR range: 1.71–1.77). The risk genotypes of both rs3737884 and 16850797 were consistently associated with common metabolic phenotypes in all three diseases (P-value range: 4.81×10−42−0.001). We observed an increase in the genetic dose-dependent cumulative risk with increasing risk allele numbers in T2D, CAD and T2D+CAD (P trend from 1.35×10−5−0.002). Conclusions: Our results suggest that ADIPOR1 risk polymorphisms are a strong candidate for the “common soil” hypothesis and could partially contribute to disease susceptibility to T2D, CAD, and T2D with CAD in the Northern Han Chinese population. [ABSTRACT FROM AUTHOR]

Background: Previous association studies examining the relationship between the APOC1 polymorphism and susceptibility to Alzheimer’s disease (AD) have shown conflicting results, and it is not clear if an APOC1 variant acts as a genetic risk factor in AD etiology across multiple populations. Methods: To confirm the risk association between APOC1 and AD, we designed a case-control study and also performed a meta-analysis of previously published studies. Results: Seventy-nine patients with AD and one hundred fifty-six unrelated controls were included in case-control study. No association was found between the variation of APOC1 and AD in stage 1 of our study. However, our meta-analysis pooled a total of 2092 AD patients and 2685 controls. The APOC1 rs11568822 polymorphism was associated with increased AD risk in Caucasians, Asians and Caribbean Hispanics, but not in African Americans. APOE ε4 carriers harboring the APOC1 insertion allele, were more prevalent in AD patients than controls (χ2 = 119.46, OR = 2.79, 95% CI = 2.31–3.36, P<0.01). Conclusions: The APOC1 insertion allele, in combination with APOE ε4, likely serves as a potential risk factor for developing AD. [ABSTRACT FROM AUTHOR]

Macrophages are heterogeneous cell populations that are present in all tissues. Macrophages can be divided into classically activated inflammatory macrophages (M1) and alternatively activated anti-inflammatory macrophages (M2). It has been generally accepted that M1 macrophages are polarised in an inflammatory environment to produce pro-inflammatory cytokines, whilst M2 macrophages are involved in anti-inflammation and aid tissue repair in wound healing. Bacterial endotoxin (lipopolysaccharide; LPS) is a potent factor in infection, which induces M1 macrophages resulting in higher levels of iNOS, TNFα and IL-12p70 which dictate inflammatory T cell responses. M2 macrophages can be transformed into M1 macrophages following LPS stimulation to promote inflammation. Candida albicans is a commensal fungal microorganism, which has been suggested to induce immune tolerance; however, the mechanism of C. albicans-induced immune tolerance has not been investigated in detail. IL-35 is a recently identified anti-inflammatory cytokine which is a heterodimeric protein consisting of the Epstein-Barr virus-induced gene 3 (EBI3) and IL-12p35. IL-35 shares the protein subunit p35, with IL-12p70. IL-12p70 is the most potent cytokine to induce Th1 responses during inflammation. In this study, we demonstrate that heat-killed C. albicans (HKC) strongly suppressed LPS-induced IL-12p70 production in M2 macrophages. Candida albicans induced a high level of EBI3 expression in M2 macrophages, which served as a mechanism for IL-12p70 suppression by competitive binding of the common protein subunit (p35) of IL-35 and IL-12p70. To demonstrate that EBI3 expression had the ability to block IL-12p70 production intracellularly, a Chinese Hamster Ovary (CHO) cell line with biscistronic expression of IL-12p40 and p35 was constructed, followed by ectopic over-expression of EBI3. The over-expression of EBI3 in the IL-12p70 producing cell line effectively suppressed IL-12p70 production. IL-35 secretion was also detected in the cell line, with suppressed IL-12p70 production by immune-precipitation Western blotting. However, this secretion was not evident in M2 macrophages following stimulation by HKC. This can be explained by the constitutive expression of IL-35 receptors (gp130 and IL-12Rβ2) in M2 macrophages for cytokine consumption. Our results have indicated that C. albicans can suppress host inflammatory responses in mucosal skin by suppressing LPS-induced IL-12p70 production. Lower IL-12p70 production may avoid an unnecessary Th1 response in order to retain immune tolerance, which may be one of the mechanisms by which C. albicans achieves a successful commensal lifestyle without having a detrimental effect on the host’s health. [ABSTRACT FROM AUTHOR]

MMPs comprise a family of proteolytic enzymes that degrade pericellular substances, which may result in the destabilization of vessels and related to the development of brain arteriovenous malformations (BAVM). MMP3 is a key member of this family, overexpressed in BAVM tissues, and a single nucleotide polymorphism within MMP3, −709A>G (rs522616), is significantly associated with the risk of BAVM. In this study, we aimed to investigate the mechanism through which the polymorphism rs522616 regulates the expression of MMP3. Our results showed that −709A led to a over 2-fold higher transcriptional activity compared with the G allele (P<0.05) and this transcriptional activity can be depressed by co-transfecting cells with competitive DNA fragments containing −709A but not −709G. Bioinformatics analyses suggested that the transcription factor C-MYB might bind to the area around rs522616. Overexpressed C-MYB significantly increased the transcriptional activity of −709A compared with −709G or controls that did not overexpress c-myb (P<0.01) in HEK293 and HUVEC cells. ChIP assays indicated that C-MYB bound to the SNP region in the two cell lines and three BAVM tissue samples. Together, these data indicated that C-MYB can bind to the −709A allele of the MMP3 promoter, activate its transcription and lead to a higher expression of this gene. This novel hypothesis, supported by molecular evidence, explains how this SNP affects MMP3 promoter function and results in a risk of BAVM development. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is the leading cause of skin infections. In a mouse model of S. aureus skin infection, we found that lesion size did not correlate with bacterial burden. Athymic nude mice had smaller skin lesions that contained lower levels of myeloperoxidase, IL-17A, and CXCL1, compared with wild type mice, although there was no difference in bacterial burden. T cell deficiency did not explain the difference in lesion size, because TCR βδ (-/-) mice did not have smaller lesions, and adoptive transfer of congenic T cells into athymic nude mice prior to infection did not alter lesion size. The differences observed were specific to the skin, because mortality in a pneumonia model was not different between wild type and athymic nude mice. Thus, the clinical severity of S. aureus skin infection is driven by the inflammatory response to the bacteria, rather than bacterial burden, in a T cell independent manner. [ABSTRACT FROM AUTHOR]