DeaD contributes to Pseudomonas aeruginosa virulence in a mouse acute pneumonia model

DExD/H box RNA helicases play essential roles in various biological processes in prokaryotes and eukaryotes. By screening Pseudomonas aeruginosa strains with mutations in various DExD/H box helicase genes, we identified that deaD was required for bacterial cytotoxicity and virulence in a mouse acute pneumonia model. Compared to a wild-type strain and its complementation strain, the deaD mutant induced less production of proinflammatory cytokines, neutrophil infiltration and lung damage during infection. We further found that the RNA helicase activity of DeaD was required for the expression of type III secretion system (T3SS) genes. Overexpression of ExsA, a master activator of the T3SS, restored the expression of T3SS genes as well as the virulence of the deaD mutant, suggesting that the attenuated virulence of the deaD mutant was mainly due to the defective T3SS. Overall, our results reveal a role of DeaD in the virulence of P. aeruginosa.

[Tetrahydrobiopterin improves left ventricular diastolic function possibly through upregulating phosphorylated protein kinase B expression in hypertensive mice induced by deoxycorticosterone acetate]

Objective: To investigate whether tetrahydrobiopterin (BH4) could improve left ventricular diastolic function through phosphoinositide-3 kinase/protein kinase B (PI3K/Akt) signaling pathway in hypertensive mice. Methods: Ten-week-old male C57BL/6 mice were used to establish the deoxycorticosterone acetate (DOCA)-salt hypertensive model, age matched Sham mice serve as the controls. Mice were divided into four groups: Sham(n=20), Sham+ BH4 (n=20), DOCA (n=22), and DOCA+ BH4 (n=22). On the 14 days after surgery, mice in Sham+ BH4 and DOCA+ BH4 groups received BH4 (0.1 ml/10 g) supplement for 7 days, while mice in Sham and DOCA groups were given equal volume of normal saline.The blood pressure measurements were performed 7 days later.Hemodynamic and echocardiographic parameters were used to assess left ventricular functions.High performance liquid chromatography (HPLC) analysis was used to measure cardiac biopterins BH4 and BH2.The phosphorylated phospholamban (p-PLB) was detected by immunohistochemical staining. PI3K, Akt and phosphorylated Akt were assayed with Western blot analysis. Results: (1) The systolic and diastolic blood pressure of DOCA group were significantly higher than control group (P<0.05). Compared with DOCA group, the systolic blood pressure was lower in DOCA+ BH4 mice (P=0.027). Diastolic blood pressure was similar between the groups. (2) Compared with Sham group, the left ventricular diastolic function indexes such as mitral annulus velocity (E') and E'/A'ratio were significantly lower, while the E/ E'ratio was significantly higher(P<0.05)in DOCA mice. The E/ E'ratio of DOCA+ BH4 group was significantly lower than that of DOCA group (P<0.05). Compared with Sham group, the left ventricular end-diastolic pressure (LVEDP), left ventricular end-diastolic pressure volumetric coefficient (EDPVR) and left ventricular relaxation time constant Tau index were significantly higher in DOCA mice (P=0.002, 0.011 and 0.016, respectively). The EDPVR and Tau index were significantly lower in DOCA+ BH4 group than in DOCA group (P<0.05). (3) Compared with Sham group, the myocardial contents of BH4 and BH2 were significantly lower in DOCA mice (P<0.05). The BH4 levels and BH4/BH2 ratio were significantly higher in Sham+ BH4 and DOCA+ BH4 groups than in the DOCA group (P<0.05), but the BH2 levels were similar between groups. (4) The cGMP content, SOD activity and NO content in the left ventricular myocardial tissue were significantly lower (P<0.05), while the MDA content was significantly higher in DOCA mice than in Sham mice.The NO content and SOD activity in DOCA+ BH4 groups were significantly higher than in the DOCA group (P<0.05). (5) Compared with DOCA group, the expression of p-PLB was significantly higher in Sham mice and lower in DOCA+ BH4 mice (P<0.05). (6) The expression of PI3K, Akt and p-Akt (Ser473 and Thr308) in DOCA mice were significantly lower than in Sham group (P<0.05). The expression of PI3K, Akt and p-Akt (Ser473) was significantly higher in DOCA+ BH4 group than in DOCA group (P<0.05). p-Akt (Thr308) expression was similar between DOCA + BH4 group and DOCA group (all P>0.05). Conclusion: Our results suggest that BH4 could improve left ventricular diastolic function in hypertensive mice, this effect might be mediated by reducing the oxidative stress in ventricular myocardium through modlating the expression of Akt and PLB phosphorylation.

Genetic association study of ABCB1 gene polymorphisms with hypertension in Han Chinese population

OBJECTIVE

Hypertension is a common disorder related to cardiovascular diseases and stroke. Identification of genetic variations related to hypertension may advance our knowledge of the molecular mechanism underlying blood pressure regulation. Here, we aimed to investigate the associations between ABCB1 gene polymorphisms and hypertension-related traits in 1154 Han Chinese subjects.

PATIENTS AND METHODS

A total of 13 SNPs in ABCB1 were genotyped.

RESULTS

Three SNPs were significantly associated with systolic blood pressure (SBP), including rs17327624 (p = 6.167 × 10-4, beta = 5.650), rs3789243 (p = 4.331 × 10-3, beta = 2.800), and rs4148734 (p = 3.514 × 10-3, beta = 3.692). Rs17327624 (p = 2.818 × 10-4, beta = 2.753) and rs3789243 (p = 6.345 × 10-3, beta = 1.497) were significantly associated with diastolic blood pressure (DBP) and rs17327624 was significantly associated with hypertension (p = 1.746 × 10-4, OR = 1.605). These three SNPs (rs17327624, rs3789243 and rs4148734) were also associated with hypertension in female subjects but no significant signal was detected in males.

CONCLUSIONS

Our results suggest that ABCB1 polymorphisms may contribute to the blood pressure variation in Han Chinese population and the effect may be specific in females. Further studies performed in other populations are needed to confirm our findings and elucidate the underlying molecular mechanism.

Mitochondrial oxygen metabolism in primary human lens epithelial cells: Association with age, diabetes and glaucoma

PURPOSE

The hypoxic environment around the lens is important for maintaining lens transparency. Lens epithelial cells (LECs) play a key role in lens metabolism. We measured oxygen consumption to assess the role of human LECs in maintaining hypoxia around the lens, as well as the impact of systemic and ocular diagnosis on these cells.

METHODS

Baseline cellular respiration was measured in rabbit LECs (NN1003A), canine kidney epithelial cells (MDCK), trabecular meshwork cells (TM-5), and bovine corneal endothelial cells (CCEE) using a XF96 Extracellular Flux Analyzer (Seahorse Bioscience, North Billerica, MA), which measures oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in vitro. Following informed written consent, lens capsule epithelial cells were obtained from patients during cataract surgery and were divided into small explants in 96-well plates. Capsules were removed when LECs became confluent. OCR was normalized to the number of cells per well using rabbit LECs as a standard. The effect of patient age, sex, race, and presence of diabetes or glaucoma on oxygen consumption was assessed by using the Mann-Whitney U test and multivariate regression analysis.

RESULTS

Primary LECs were obtained from 69 patients. The OCR from donors aged 70 and over was lower than that of those under 70 years (2.21±1.037 vs. 2.86±1.383 fmol/min/cell; p<0.05). Diabetic patients had lower OCR than non-diabetic patients (2.02±0.911 vs. 2.79±1.332fmol/min/cell; p<0.05), and glaucoma patients had lower OCR than non-glaucoma patients (2.27±1.19 vs. 2.83±1.286 fmol/min/cell; p<0.05). Multivariate regression analysis confirmed that donors aged 70 and over (p<0.05), diabetic patients (p<0.01), and glaucoma patients (p<0.05) had significantly lower OCR, independent of other variables. Gender and race had no significant effect on OCR.

CONCLUSIONS

The lower oxygen consumption rate of human LECs in older donors and patients with diabetes or glaucoma could contribute to cataract development. Diabetes and glaucoma are particularly important factors associated with decreased OCR, independent of age. Ongoing studies are examining pO2 at the anterior surface of the lens in vivo and oxygen consumption in the patient's LECs.

A Combined Quantitative Structure-Activity Relationship Research of Quinolinone Derivatives as Androgen Receptor Antagonists

Antiandrogens bicalutamide, flutamide and enzalutamide etc. have been used in clinical trials to treat prostate cancer by binding to and antagonizing androgen receptor (AR). Although initially effective, the drug resistance problem will emerge eventually, which results in a high medical need for novel AR antagonist exploitation. Here in this work, to facilitate the rational design of novel AR antagonists, we studied the structure-activity relationships of a series of 2-quinolinone derivatives and investigated the structural requirements for their antiandrogenic activities. Different modeling methods, including 2D MLR, 3D CoMFA and CoMSIA, were implemented to evolve QSAR models. All these models, thoroughly validated, demonstrated satisfactory results especially for the good predictive abilities. The contour maps from 3D CoMFA and CoMSIA models provide visualized explanation of key structural characteristics relevant to the antiandrogenic activities, which is summarized to a position-specific conclusion at the end. The obtained results from this research are practically useful for rational design and screening of promising chemicals with high antiandrogenic activities.

Synthetically Tuning the 2-Position of Halogenated Quinolines: Optimizing Antibacterial and Biofilm Eradication Activities via Alkylation and Reductive Amination Pathways

Agents capable of eradicating bacterial biofilms are of great importance to human health as biofilm-associated infections are tolerant to our current antibiotic therapies. We have recently discovered that halogenated quinoline (HQ) small molecules are: 1) capable of eradicating methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE) and vancomycin-resistant Enterococcus faecium (VRE) biofilms, and 2) synthetic tuning of the 2-position of the HQ scaffold has a significant impact on antibacterial and antibiofilm activities. Here, we report the chemical synthesis and biological evaluation of 39 HQ analogues that have a high degree of structural diversity at the 2-position. We identified diverse analogues that are alkylated and aminated at the 2-position of the HQ scaffold and demonstrate potent antibacterial (MIC≤0.39 μm) and biofilm eradication (MBEC 1.0-93.8 μm) activities against drug-resistant Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecium strains while demonstrating <5 % haemolysis activity against human red blood cells (RBCs) at 200 μm. In addition, these HQs demonstrated low cytotoxicity against HeLa cells. Halogenated quinolines are a promising class of antibiofilm agents against Gram-positive pathogens that could lead to useful treatments against persistent bacterial infections.

Structure-Activity Relationships of a Diverse Class of Halogenated Phenazines That Targets Persistent, Antibiotic-Tolerant Bacterial Biofilms and Mycobacterium tuberculosis

Persistent bacteria, including persister cells within surface-attached biofilms and slow-growing pathogens lead to chronic infections that are tolerant to antibiotics. Here, we describe the structure-activity relationships of a series of halogenated phenazines (HP) inspired by 2-bromo-1-hydroxyphenazine 1. Using multiple synthetic pathways, we probed diverse substitutions of the HP scaffold in the 2-, 4-, 7-, and 8-positions, providing critical information regarding their antibacterial and bacterial eradication profiles. Halogenated phenazine 14 proved to be the most potent biofilm-eradicating agent (≥99.9% persister cell killing) against MRSA (MBEC < 10 μM), MRSE (MBEC = 2.35 μM), and VRE (MBEC = 0.20 μM) biofilms while 11 and 12 demonstrated excellent antibacterial activity against M. tuberculosis (MIC = 3.13 μM). Unlike antimicrobial peptide mimics that eradicate biofilms through the general lysing of membranes, HPs do not lyse red blood cells. HPs are promising agents that effectively target persistent bacteria while demonstrating negligible toxicity against mammalian cells.

Impact of Corneal Endothelial Dysfunctions on Intraocular Oxygen Levels in Human Eyes

PURPOSE

We studied the implications of corneal endothelial dysfunctions on oxidative stress in the anterior segment via in vivo measurements of oxygen partial pressure (pO2) in the anterior chamber (AC) of human eyes.

METHODS

We recruited 51 patients undergoing cataract surgery and/or endothelial keratoplasty (EK). Endothelial cell density (ECD; n = 33) and central corneal thickness (CCT; n = 41) were measured on patients with relatively clear corneas. Before surgery, an oxygen sensor was introduced into the AC via a peripheral corneal paracentesis. In all patients, seven measurements of pO2 were obtained by positioning the flexible tip near the endothelium at the central cornea, at four cardinal subendothelial locations near the midperipheral cornea, and in the mid-AC and AC angle. In patients with pseudophakia or eyes undergoing cataract surgery, pO2 also was measured near the lens surface and in the posterior chamber.

RESULTS

Consistent with our previous reports, a steep oxygen gradient was noted in the anterior segment of normal controls (n = 24). In patients with endothelial dysfunctions (n = 27), there was a significant increase of pO2 at all five subendothelial locations without a significant increase of pO2 in the AC angle. By regression analyses, subendothelial pO2 correlated inversely with ECD and positively with CCT in patients with endothelial dysfunctions.

CONCLUSIONS

This study demonstrates an even steeper intraocular oxygen gradient in eyes with corneal endothelial dysfunctions. It suggests that the reduced oxygen consumption in corneal endothelial cells may increase oxidative stress in the AC and the existence of an alternative aqueous inflow pathway that maintains a relatively low and constant pO2 at the AC angle.

Cloning, Characterization and Expression Pattern Analysis of a Cytosolic Copper/Zinc Superoxide Dismutase (SaCSD1) in a Highly Salt Tolerant Mangrove (Sonneratia alba)

Mangroves are critical marine resources for their remarkable ability to tolerate seawater. Antioxidant enzymes play an especially significant role in eliminating reactive oxygen species and conferring abiotic stress tolerance. In this study, a cytosolic copper/zinc superoxide dismutase (SaCSD1) cDNA of Sonneratia alba, a mangrove species with high salt tolerance, was successfully cloned and then expressed in Escherichia coli Rosetta-gami (designated as SaCSD1). SaCSD1 comprised a complete open reading frame (ORF) of 459 bp which encoded a protein of 152 amino acids. Its mature protein is predicted to be 15.32 kDa and the deduced isoelectric point is 5.78. SaCSD1 has high sequence similarity (85%-90%) with the superoxide dismutase (CSD) of some other plant species. SaCSD1 was expressed with 30.6% yield regarding total protein content after being introduced into the pET-15b (Sma I) vector for expression in Rosetta-gami and being induced with IPTG. After affinity chromatography on Ni-NTA, recombinant SaCSD1 was obtained with 3.2-fold purification and a specific activity of 2200 U/mg. SaCSD1 showed good activity as well as stability in the ranges of pH between 3 and 7 and temperature between 25 and 55 °C. The activity of recombinant SaCSD1 was stable in 0.25 M NaCl, Dimethyl Sulphoxide (DMSO), glycerol, and chloroform, and was reduced to a great extent in β-mercaptoethanol, sodium dodecyl sulfate (SDS), H₂O2, and phenol. Moreover, the SaCSD1 protein was very susceptive to pepsin digestion. Real-time Quantitative Polymerase Chain Reaction (PCR) assay demonstrated that SaCSD1 was expressed in leaf, stem, flower, and fruit organs, with the highest expression in fruits. Under 0.25 M and 0.5 M salt stress, the expression of SaCSD1 was down-regulated in roots, but up-regulated in leaves.

Halogenated Phenazines that Potently Eradicate Biofilms, MRSA Persister Cells in Non-Biofilm Cultures, and Mycobacterium tuberculosis

Conventional antibiotics are ineffective against non-replicating bacteria (for example, bacteria within biofilms). We report a series of halogenated phenazines (HP), inspired by marine antibiotic 1, that targets persistent bacteria. HP 14 demonstrated the most potent biofilm eradication activities to date against MRSA, MRSE, and VRE biofilms (MBEC = 0.2-12.5 μM), as well as the effective killing of MRSA persister cells in non-biofilm cultures. Frontline MRSA treatments, vancomycin and daptomycin, were unable to eradicate MRSA biofilms or non-biofilm persisters alongside 14. HP 13 displayed potent antibacterial activity against slow-growing M. tuberculosis (MIC = 3.13 μM), the leading cause of death by bacterial infection around the world. HP analogues effectively target persistent bacteria through a mechanism that is non-toxic to mammalian cells and could have a significant impact on treatments for chronic bacterial infections.

Directed Differentiation of Embryonic Stem Cells Into Cardiomyocytes by Bacterial Injection of Defined Transcription Factors

Forced expression of defined transcriptional factors has been well documented as an effective method for cellular reprogramming or directed differentiation. However, transgene expression is not amenable for therapeutic application due to potential insertional mutagenesis. Here, we have developed a bacterial type III secretion system (T3SS)-based protein delivery tool and shown its application in directing pluripotent stem cell differentiation by a controlled delivery of transcription factors relevant to early heart development. By fusing to an N-terminal secretion sequence for T3SS-dependent injection, three transcriptional factors, namely Gata4, Mef2c, and Tbx5 (abbreviated as GMT), were translocated into murine embryonic stem cells (ESCs), where the proteins are effectively targeted to the nucleus with an average intracellular half-life of 5.5 hours. Exogenous GMT protein injection activated the cardiac program, and multiple rounds of GMT protein delivery significantly improved the efficiency of ESC differentiation into cardiomyocytes. Combination of T3SS-mediated GMT delivery and Activin A treatment showed an additive effect, resulting in on average 60% of the ESCs differentiated into cardiomyocytes. ESC derived cardiomyocytes displayed spontaneous rhythmic contractile movement as well as normal hormonal responses. This work serves as a foundation for the bacterial delivery of multiple transcription factors to direct cell fate without jeopardizing genomic integrity.

Identification of matrine as a promising novel drug for hepatic steatosis and glucose intolerance with HSP72 as an upstream target

BACKGROUND AND PURPOSE

Matrine is a small molecule drug used in humans for the treatment of chronic viral infections and tumours in the liver with little adverse effects. The present study investigated its therapeutic efficacy for insulin resistance and hepatic steatosis in high-fat-fed mice.

EXPERIMENTAL APPROACH

C57BL/J6 mice were fed a chow or high-fat diet for 10 weeks and then treated with matrine or metformin for 4 weeks. The effects on lipid metabolism and glucose tolerance were evaluated.

KEY RESULTS

Our results first showed that matrine reduced glucose intolerance and plasma insulin level, hepatic triglyceride content and adiposity in high-fat-fed mice without affecting caloric intake. This reduction in hepatosteatosis was attributed to suppressed lipid synthesis and increased fatty acid oxidation. In contrast to metformin, matrine neither suppressed mitochondrial respiration nor activated AMPK in the liver. A computational docking simulation revealed HSP90, a negative regulator of HSP72, as a potential binding target of matrine. Consistent with the simulation results, matrine, but not metformin, increased the hepatic protein level of HSP72 and this effect was inversely correlated with both liver triglyceride level and glucose intolerance.

CONCLUSIONS AND IMPLICATIONS

Taken together, these results indicate that matrine may be used for the treatment of type 2 diabetes and hepatic steatosis, and the molecular action of this hepatoprotective drug involves the activation of HSP72 in the liver.

Joint effects of gray matter atrophy and altered functional connectivity on cognitive deficits in amnestic mild cognitive impairment patients

BACKGROUND

Gray matter (GM) atrophy and disrupted intrinsic functional connectivity (IFC) are often present in patients with amnestic mild cognitive impairment (aMCI), which shows high risk of developing into Alzheimer's disease. Little is known, however, about the relationship between GM atrophy and altered IFC, and whether they are related to cognitive decline.

METHOD

A total of 30 aMCI and 26 cognitively normal (CN) subjects were recruited for this study. Optimized voxel-based morphometric and resting-state functional connectivity magnetic resonance imaging approaches were performed to measure the GM volumes (GMVs) and atrophy-related IFC, respectively. Multivariate linear regression analysis was used to examine the effects of GM atrophy and IFC on cognitive performance across subjects, after controlling for the effects of age, education, gender and group.

RESULTS

Compared with CN subjects, aMCI subjects showed significantly reduced GMVs and decreased IFC in the frontal-parietal and medial temporal lobe systems. Multivariate regression analysis further demonstrated that the GMVs and decreased IFC simultaneously affected the cognitive function. Specifically, GMVs were positively correlated with cognitive performances, including global cognition and episodic memory, and showed a strong trend in correlation between GMVs and non-episodic memory, whilst IFC was positively correlated with the above three cognitive measures, across all subjects. In addition, significant correlation was found between GMVs and altered IFC strength across all subjects.

CONCLUSIONS

Our findings demonstrated that GMVs and IFC jointly contribute to cognitive performance, and combining quantitative information about GMVs and the strength of functional connectivity may serve as an indicator of cognitive deficits in non-demented elderly.

Efficient Gene Editing in Pluripotent Stem Cells by Bacterial Injection of Transcription Activator-Like Effector Nuclease Proteins

The type III secretion system (T3SS) of Pseudomonas aeruginosa is a powerful tool for direct protein delivery into mammalian cells and has successfully been used to deliver various exogenous proteins into mammalian cells. In the present study, transcription activator-like effector nuclease (TALEN) proteins have been efficiently delivered using the P. aeruginosa T3SS into mouse embryonic stem cells (mESCs), human ESCs (hESCs), and human induced pluripotent stem cells (hiPSCs) for genome editing. This bacterial delivery system offers an alternative method of TALEN delivery that is highly efficient in cleavage of the chromosomal target and presumably safer by avoiding plasmid DNA introduction. We combined the method of bacterial T3SS-mediated TALEN protein injection and transfection of an oligonucleotide template to effectively generate precise genetic modifications in the stem cells. Initially, we efficiently edited a single-base in the gfp gene of a mESC line to silence green fluorescent protein (GFP) production. The resulting GFP-negative mESC was cloned from a single cell and subsequently mutated back to a GFP-positive mESC line. Using the same approach, the gfp gene was also effectively knocked out in hESCs. In addition, a defined single-base edition was effectively introduced into the X-chromosome-linked HPRT1 gene in hiPSCs, generating an in vitro model of Lesch-Nyhan syndrome. T3SS-mediated TALEN protein delivery provides a highly efficient alternative for introducing precise gene editing within pluripotent stem cells for the purpose of disease genotype-phenotype relationship studies and cellular replacement therapies.

Investigation of cell aggregation on the substrate of a parallel-plate flow chamber

Adhesion of tumor cells (TCs) to polymorphonuclear neutrophils (PMNs) tethered on a monolayer of vascular endothelial cells (ECs) in shear flows is investigated theoretically. Both TC&mdash;PMN and PMN&mdash;EC aggregations are modeled using the population balance equations (PBEs). Parameters in the model obtained by curve fitting show that an increase of shear rate or viscosity will suppress the formation of aggregates and promote the breakage of them. Analysis on the collision frequency suggests that the averaged encounter duration is affected by viscosity. Based on the model, a nonlinear connection between the number of migrated TCs and the concentration of PMNs in the flow near the substrate is presented.

Assessment of radiological vertebral fractures in HIV-infected patients: clinical implications and predictive factors

OBJECTIVES

The aim of this study was to evaluate the clinical impact of including lateral spine X-ray in the screening of bone diseases in HIV-positive patients.

METHODS

A total of 194 HIV-positive patients underwent dual-energy X-ray absorptiometry (DEXA), lateral spine X-ray and bone biochemical analysis. Vertebral fractures were identified using a morphometric analysis of X-rays and classified using the semiquantitative scoring system of Genant et al. For each patient, a spine deformity index (SDI) score was calculated by summing the grades of vertebral deformities. Reductions in vertebral body height of > 25% were considered vertebral fractures, and those < 25% were considered vertebral deformities. Risk factors associated with vertebral fractures were evaluated by univariate and multivariate analysis.

RESULTS

Vertebral fractures were detected in 24 patients (12.4%) and vertebral deformities in 17 patients (8.7%); 153 patients (78.9%) did not show any vertebral deformity. Among patients with fractures, only two with SDI > 10 reported lumbar pain; the remaining were asymptomatic. Patients over 50 years old showed a higher prevalence of vertebral fracture [24.4% versus 11.8% in patients 41-50 years old (P = 0.05) and 1.9% in patients ≤ 40 years old (P = 0.04)]. No significant increase in the prevalence according to bone mineral density (BMD) reduction was observed, and 70% of fractures were diagnosed in nonosteoporotic patients. Older age [adjusted odds ratio 1.09; 95% confidence interval (CI) 1.03-1.13; P = 0.001] and steroid use (adjusted odds ratio 3.64; 95% CI 1.29-10.3; P = 0.01) were independently associated with vertebral fracture; no association was found with HIV- or highly active antiretroviral therapy (HAART)-related variables.

CONCLUSIONS

A prevalence of vertebral fractures of 12.4% was observed in our HIV-positive cohort. Given that two-thirds of fractures occurred in nonosteoporotic patients, spine X-ray may be considered in patients at increased risk, irrespective of BMD; that is, in elderly patients and/or patients using steroids.

A test of lens opacity as an indicator of preclinical Alzheimer Disease

Previous studies reported that characteristic lens opacities were present in Alzheimer Disease (AD) patients postmortem. We therefore determined whether cataract grade or lens opacity is related to the risk of Alzheimer dementia in participants who have biomarkers that predict a high risk of developing the disease. AD biomarker status was determined by positron emission tomography-Pittsburgh compound B (PET-PiB) imaging and cerebrospinal fluid (CSF) levels of Aβ42. Cognitively normal participants with a clinical dementia rating of zero (CDR = 0; N = 40) or with slight evidence of dementia (CDR = 0.5; N = 2) were recruited from longitudinal studies of memory and aging at the Washington University Knight Alzheimer's Disease Research Center. The age, sex, race, cataract type and cataract grade of all participants were recorded and an objective measure of lens light scattering was obtained for each eye using a Scheimpflug camera. Twenty-seven participants had no biomarkers of Alzheimer dementia and were CDR = 0. Fifteen participants had biomarkers indicating increased risk of AD, two of which were CDR = 0.5. Participants who were biomarker positive were older than those who were biomarker negative. Biomarker positive participants had more advanced cataracts and increased cortical light scattering, none of which reached statistical significance after adjustment for age. We conclude that cataract grade or lens opacity is unlikely to provide a non-invasive measure of the risk of developing Alzheimer dementia.

Central corneal thickness correlates with oxygen levels in the human anterior chamber angle

PURPOSE

To measure oxygen (pO2) in eyes of patients undergoing intraocular surgery and identify correlations with central corneal thickness (CCT).

DESIGN

Prospective, cross-sectional study.

METHODS

setting: Institutional. patient population: 124 patients undergoing cataract and/or glaucoma surgery. observation procedure: Prior to surgery, an oxygen sensor was introduced into the anterior chamber (AC) via peripheral corneal paracentesis. The tip of the flexible fiberoptic probe was positioned for 3 measurements in all patients: (1) near central corneal endothelium; (2) in mid-AC; and (3) in AC angle. In patients undergoing cataract extraction, additional measurements were taken (4) at the anterior lens surface and (5) in the posterior chamber. main outcome measures: pO2 measurements at 5 locations within the eye were compared to central corneal thickness measurements by multivariate regression analyses.

RESULTS

There was a statistically significant inverse correlation between CCT and pO2 in the anterior chamber angle (P = .048). pO2 was not significantly related to CCT at any other location, including beneath the central cornea. Regression analysis relating CCT to age, race, and oxygen levels in all 5 locations in the anterior segment revealed an association of a thinner cornea with increasing age (P = .007).

CONCLUSIONS

Physiologic correlations with central corneal thickness may provide clues to understanding why a thinner cornea increases the risk of open glaucoma. Associations between glaucoma risk, CCT, and pO2 in the AC angle suggest that exposure of the outflow system to increased oxygen or oxygen metabolites may increase oxidative damage to the trabecular meshwork cells, resulting in elevation of intraocular pressure.

Assessment of growth rate, chlorophyll a fluorescence, lipid peroxidation and antioxidant enzyme activity in Aphanizomenon flos-aquae, Pediastrum simplex and Synedra acus exposed to cadmium

In this study, the effects of cadmium on the cyanobacterium Aphanizomenon flos-aquae, the green alga Pediastrum simplex and the diatom Synedra acus was evaluated on the basis of growth rate, chlorophyll a fluorescence, lipid peroxidation and antioxidant enzyme activity. The EC50 values (effective concentration inducing 50 % of growth inhibition) of cadmium in A. flos-aquae, P. simplex and S. acus were 1.18 ± 0.044, 4.32 ± 0.068 and 3.7 ± 0.055 mg/L, respectively. The results suggested that cadmium stress decreases growth rate and chlorophyll a concentration. The normalized chlorophyll a fluorescence transients significantly increased at cadmium concentrations of 5.0, 10.0 and 20.0 mg/L, but slightly decreased at concentrations of 0.2, 0.5 and 1.0 mg/L. The chlorophyll fluorescence parameters showed considerable variation among the three species, while lipid peroxidation and antioxidant enzyme activities showed a significant increase. Our results demonstrated that blockage of electron transport on the acceptor side of photosystem II is the mechanism responsible for cadmium toxicity in freshwater microalgae, and that the tolerance of the three species to cadmium was in the order green alga P. simplex > diatom S. acus > cyanobacterium A. flos-aquae.

Comparison of calycosin and irbesartan for their impact on renin angiotensin system in human umbilical vein endothelial cell

AIM

The aim of this paper was to compare the efficacy of in vitro calycosin and irbesartan for the treatment of angiotensin II (AngII)-induced renin angiotensin system (RAS) disorder in human umbilical vein endothelial cells (HUVECs).

METHODS

Cultured HUVECs were randomly divided into several groups: control, AngII 1×10-6 mol) alone, Ang II (1×10-6 mol) plus calycosin (0.1, 1, 10 mg/L) and Ang II (1×10-6 mol) plus Irbesartan (10 μmol). Morphology of vascular endothelial cells was studied by using a light microscope with hematoxylin and eosin double staining. Changes in both protein and gene expression of Angiotensin-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2) were detected by immunohistochemistry analysis and reverse transcription polymerase chain reaction (RT-PCR) techniques, respectively.

RESULTS

In comparison to control, AngII significantly promoted both protein and gene expressions of ACE while inhibited those of ACE2 in HUVECs. Interestingly, Calycosin was able to inhibit the effect of AngII in a concentration dependent manner, and its effect at concentration of 35 μmol was equal to that of positive control Irbesartan (10μmol).

CONCLUSION

Calycosin from Radix Astragali from Gansu province could protect HUVECs from AngII induced RAS disorder by downregulation of ACE expression and increased ACE2 expression, which is similar to irbesartan. These results suggest that calycosin may be a promising candidate for treatment of endothelial dysfunction.

Bromophenazine derivatives with potent inhibition, dispersion and eradication activities against Staphylococcus aureus biofilms

Bacterial biofilms are surface-attached communities of bacteria that are: (1) highly prevalent in human infections, and (2) resistant to conventional antibiotic treatments and host immune responses.

Phenazine antibiotic inspired discovery of potent bromophenazine antibacterial agents against Staphylococcus aureus and Staphylococcus epidermidis

Nearly all clinically used antibiotics have been (1) discovered from microorganisms (2) using phenotype screens to identify inhibitors of bacterial growth. The effectiveness of these antibiotics is attributed to their endogenous roles as bacterial warfare agents against competing microorganisms. Unfortunately, every class of clinically used antibiotic has been met with drug resistant bacteria. In fact, the emergence of resistant bacterial infections coupled to the dismal pipeline of new antibacterial agents has resulted in a global health care crisis. There is an urgent need for innovative antibacterial strategies and treatment options to effectively combat drug resistant bacterial pathogens. Here, we describe the implementation of a Pseudomonas competition strategy, using redox-active phenazines, to identify novel antibacterial leads against Staphylococcus aureus and Staphylococcus epidermidis. In this report, we describe the chemical synthesis and evaluation of a diverse 27-membered phenazine library. Using this microbial warfare inspired approach, we have identified several bromophenazines with potent antibacterial activities against S. aureus and S. epidermidis. The most potent bromophenazine analogue from this focused library demonstrated a minimum inhibitory concentration (MIC) of 0.78-1.56 μM, or 0.31-0.62 μg mL(-1), against S. aureus and S. epidermidis and proved to be 32- to 64-fold more potent than the phenazine antibiotic pyocyanin in head-to-head MIC experiments. In addition to the discovery of potent antibacterial agents against S. aureus and S. epidermidis, we also report a detailed structure-activity relationship for this class of bromophenazine small molecules.

[Preliminary study on CT retrograde intubation dacryosystography (CT-RIDC) and its impact factors]

OBJECTIVE

To observe practicality and safety of CT-RIDC for the patients with presaccular lacrimal obstruction and study the related factors. To provide guidance for the diagnosis and treatment of the patients with presaccular lacrimal obstruction.

METHODS

Fifty-four patients (75 eyes) with presaccular lacrimal obstruction, including 3 cases (5 eyes) of upper and lower lacrimal punctum atresia, 15 cases (24 eyes) of superior and inferior canalicular obstruction, 18 cases (28 eyes) of common canaliculus obstruction, 18 cases (18 eyes) of old laceration of superior and inferior canalicular, were recruited. All patients underwent the examination by using 0° and 30° ear endoscope and the imaging characteristics of the inferior orifice of nasolacrimal duct were obtained. Fifty-three cases (65 eyes) with the opening inferior orifice were randomly divided into four groups (15 eyes, 17 eyes, 17 eyes, 16 eyes) according to different angle of head hypsokinesis in the supine position. The OM lines back along the sagittal plane of the head back 10°, 20°, 30°, 40° were measured. The angles of head hypsokinesis were set in accordance with the OM line measurement results.Intubation was successful when the intubation guided needle within the set of epidural anesthetic catheter aided with endoscopy was inserted into the inferior orifice of nasolacrimal duct and then the epidural anesthetic catheter was inserted into the lacrimal duct 6 mm. The angle (θ) between the long axis of the curved part of the intubation guided needle and the long axis of the guided needle was measured. The numbers of intubation success cases in each group were recorded.χ² test was used to compare intubation success rate under the different angle of head hypsokinesis.Scheffe method was used to compare intubation success rate between each group. Contrast medium was then injected into lacrimal duct through the epidural anesthetic catheter for patients with successful intubation and CT scan was carried out. 3D model of lacrimal passage was reconstructed with CT axial scanning.

RESULTS

The intubation guided needle was successfully inserted into the inferior orifice of nasolacrimal duct in 44 eyes among 65 eyes with the opening orifice. The number of successful intubation cases were 4 eyes, 15 eyes, 13 eyes, 12 eyes and the intubation success rate was 26.67%, 88.24%, 76.74%, 75.00% according the angle of head hypsokinesis 10° group (15 eyes), 20° group (17 eyes), 30° group (17 eyes), 40° group (16 eyes). The intubation success rate of head hypsokinesis 10° group was significantly lower than that of the other groups. Multiple Comparison by Scheffe Test demonstrated that there was a remarkable difference (P < 0.05) in the intubation success rate between head hypsokinesis 10° group and the other three groups. There were no significant differences in the intubation success rate among head hypsokinesis 20° group, head hypsokinesis 30° group and head hypsokinesis 40° group. The mean of θ was 108° with a range of 93.2°-120.5° by measuring the angle θ of the successful intubation cases. According to the frequency distribution plot, most θ was in 104°-115°. The successful intubation cases (44 eyes) underwent CT scan in the same position immediately after injected contrast medium (Optiray) through the epidural anesthetic catheter. CT images of 28 eyes showed retained contrast medium in the nasolacrimal duct and lacrimal sac. The findings from CT-DCG images were basically agreed with the operation.

CONCLUSIONS

CD-RIDC may apply to pre-operative examination for the patients with the opening orifice and presaccular lacrimal obstruction.It provideed imaging evidence for diagnosis and therapy and it was safe and practical. Many factors could affect CD-RIDC. The main verified facors were the shape of the inferior orifice of nasolacrimal duct, head position of the patient and the bending angle of the tip of intubation guided needle.

Diagnosis of lacrimal canalicular diseases using ultrasound biomicroscopy: a preliminary study

AIM

To evaluate the application of ultrasound biomicroscopy (UBM) in the examination of lacrimal canalicular diseases, and to investigate UBM image characteristics of lacrimal canaliculi in disease states.

METHODS

Sixty cases (63 eyes, 69 canaliculi) of lacrimal canalicular diseases were enrolled that included 32 patients (32 eyes, 32 canaliculi) with chronic lacrimal canaliculitis, 18 patients (18 eyes, 18 canaliculi) with previous lacrimal canalicular laceration, 9 patients (12 eyes, 18 canaliculi) with congenital absence of lacrimal puncta and canaliculi, and 1 case (1 eye, 1 canaliculus) of canalicular mass. The patients were examined using UBM, and disease-specific features of the UBM images were noted.

RESULTS

UBM imaging of lacrimal canaliculi in chronic canaliculitis patients showed obvious ectasia of the lacrimal canalicular lumen. Dot-like moderate echoic signals were detected on some ectatic lumina of the lacrimal canaliculus. Some lumen-like structures of the lower lacrimal canaliculus were observed in 2 (2 eyes, 2 canaliculi) of the 9 patients (12 eyes, 18 canaliculi) with congenital absence of the lacrimal canaliculus. Of the 18 patients (18 eyes, 18 canaliculi) with previous lacrimal canalicular laceration, the lacerated end on the nasal side of the lacrimal canaliculus was detected only in 14 patients (14 eyes, 14 canaliculi).

CONCLUSION

UBM can be used to evaluate lacrimal canalicular diseases and can provide an imaging basis for the diagnosis of lacrimal canalicular diseases.

A strategy for fusion expression and preparation of functional glucagon-like peptide-1 (GLP-1) analogue by introducing an enterokinase cleavage site

KGLP-1, a 31-amino acid glucagon-like peptide-1 (GLP-1) analogue, has a great therapeutic potential for anti-diabetes. In this work, a strategy for expression and purification of functional KGLP-1 peptide has been established. KGLP-1 cDNA was fused with glutathione S-transferase (GST), with an enterokinase cleavage site in the fusion junction. The recombinant fusion protein GST-KGLP-1 was affinity purified via the GST-tag, and then digested with enterokinase. The resulting GST part as well as the enzymes were eliminated by ultra-filtration followed by size exclusion chromatograph. The yield of purified KGLP-1 was approximately 12.1 mg/L, with purity of 96.18 %. The recombinant KGLP-1 was shown to have similar bioactivity as native GLP-1 when evaluated in a Chinese hamster ovary cell line expressing a GLP-1 receptor-egfp reporter gene.

Pseudomonas aeruginosa injects NDK into host cells through a type III secretion system

Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen possessing a type III secretion system (T3SS) which injects toxic effector proteins into mammalian host cells. In previous studies, P. aeruginosa strains lacking all of the known type III effectors were shown to cause cytotoxicity upon prolonged infection time. In this study, we report the identification of a new cytotoxin, nucleoside diphosphate kinase (NDK), which is injected into eukaryotic cells in a T3SS-dependent manner. Injection of NDK is inhibited by the presence of previously known effectors of the T3SS, with an effectorless strain injecting the highest amount, suggesting active competition with the known T3SS effectors. NDK is shown to cause a cytotoxic response when expressed in eukaryotic cells, and P. aeruginosa strains harbouring NDK also show a greater toxicity than strains lacking it. Interestingly, the cytotoxic effect of intracellular NDK is independent of its kinase activity. In previous studies, NDK was shown to be secreted into culture supernatants via a type I secretion system and cause cytotoxicity in a kinase-dependent manner. Therefore, the current study highlights an alternative route of NDK secretion as well as two different cytotoxic mechanisms of NDK, depending on the extra- or intra-cellular location of the protein.

Breech presentation at delivery: a marker for congenital anomaly?

OBJECTIVE

To determine whether congenital anomalies are associated with breech presentation at the time of birth.

STUDY DESIGN

A population-based, retrospective cohort study was conducted among 460,147 women with singleton live births using the Missouri Birth Defects Registry, which includes all defects diagnosed during the first year of life. Maternal and obstetric characteristics and outcomes between breech and cephalic presentation groups were compared using χ(2)-square statistic and Student's t-test. Multivariable binary logistic regression analysis was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULT

At least one congenital anomaly was more likely present among infants breech at birth (11.7%) than in those with cephalic presentation (5.1%), whether full-term (9.4 vs 4.6%) or preterm (20.1 vs 11.6%). The relationship between breech presentation and congenital anomaly was stronger among full-term births (aOR 2.09, CI 1.96, 2.23, term vs 1.40, CI 1.26, 1.55, preterm), but not in all categories of anomalies.

CONCLUSION

Breech presentation at delivery is a marker for the presence of congenital anomaly. Infants delivered breech deserve special scrutiny for the presence of malformation.

[Novel immobilization of arginase I via cellulose-binding domain and its application in producing of L-ornitine]

The recombinant Escherichia coli strain pET35b-ARG, which overexpresses arginase I fused to a cellulose-binding domain (CBD), was developed. After preparing cellulose microspheres, arginase I was immobilized via the CBD of the fusion protein. Under optimal reaction conditions (40 degrees C, pH 9.5, 1 mM of Mn2+, 30 microl/ml of immobilized enzyme, 30 g/l of L-Arg, and for I h), the conversion rate of L-Arg was 98.7%. After 7 reuses of 30 microl of immobilized enzyme in 1 ml of catalytic solution, 153 mg of L-Orn with 97.3% purity was obtained. This indicated that the immobilization method was effective, feasible and could be used for the industrial production of L-Orn in the future.

Imprinting in plants as a mechanism to generate seed phenotypic diversity

Normal plant development requires epigenetic regulation to enforce changes in developmental fate. Genomic imprinting is a type of epigenetic regulation in which identical alleles of genes are expressed in a parent-of-origin dependent manner. Deep sequencing of transcriptomes has identified hundreds of imprinted genes with scarce evidence for the developmental importance of individual imprinted loci. Imprinting is regulated through global DNA demethylation in the central cell prior to fertilization and directed repression of individual loci with the Polycomb Repressive Complex 2 (PRC2). There is significant evidence for transposable elements and repeat sequences near genes acting as cis-elements to determine imprinting status of a gene, implying that imprinted gene expression patterns may evolve randomly and at high frequency. Detailed genetic analysis of a few imprinted loci suggests an imprinted pattern of gene expression is often dispensable for seed development. Few genes show conserved imprinted expression within or between plant species. These data are not fully explained by current models for the evolution of imprinting in plant seeds. We suggest that imprinting may have evolved to provide a mechanism for rapid neofunctionalization of genes during seed development to increase phenotypic diversity of seeds.

One-stitch anastomosis through the skin with bicanalicular intubation: a modified approach for repair of bicanalicular laceration

AIM

To evaluate the efficacy and safety of one-stitch anastomosis through the skin with bicanalicular silicone tube intubation in repairing of bicanalicular laceration.

METHODS

The clinical data of 15 consecutive patients with both superior and inferior canalicular laceration in one eye who underwent surgical repair using one-stitch anastomosis through the skin and bicanalicular stent were retrospective studied. All the operations were performed under surgical microscope, 5-0 silk sutures were used and were with bicanalicular silicone tube (diameter was 8mm) intubation, for one lacerated canaliculi one-stitch anastomosis through the skin. The stents were left in place for 3 months postoperatively and then removed. The follow-up period was 3 - 36 months (average 14 months).

RESULTS

In 15 patients, 13 patients were cured entirely, 1 patient was meliorated, 1 patient with no effects. All patients had got good recovery of eyelid laceration with no traumatic deformity in eyelid and canthus. Complication was seen in one case, for not followed the doctor's guidance to come back to hospital to had the suture removed on the 7(th) day after operation, when he came at the 15(th) day, the inferior canalicular wall and eyelid skin were corroded by the suture caused 2mm wound, and the inside silicone tube was exposed, a promptly repair with 10-0 nylon suture was done, the wound healed in a week. There were no early tube protrusions and punctal slits in the patients.

CONCLUSION

One-stitch anastomosis through the skin with bicanalicular silicone tube intubation is a good method in repair of bicanalicular laceration in one eye, the cut ends can be anastomosed directly, and with excellent cosmetic results, it is acceptable for the patients. For there is no suture remained in the wound permanently, so there is no suture-related granuloma which may cause obstruction or stenosis of canaliculi. It is simple, economical, effective and safe.

Two novel potent α-amylase inhibitors from the family of acarviostatins isolated from the culture of Streptomyces coelicoflavus ZG0656

Two novel aminooligosaccharides were separated from the culture filtrate of Streptomyces coelicoflavus ZG0656. Their chemical structures were determined by acidic hydrolysis, electrospray-ionization tandem mass spectrometry (ESI-MS/MS), and NMR spectroscopy. The compounds were named acarviostatins III0(-1) and III23 according to the nomenclature of this group of metabolites. The two novel acarviostatins were both mixed noncompetitive inhibitors of porcine pancreatic α-amylase (PPA). The inhibition constants (K(i)) for acarviostatins III0(-1) and III23 were 0.009 and 0.026 μM, respectively, 151 and 52 times more potent than acarbose.

Inhibitory effect of components from Streptomyces species on alpha-glucosidase and alpha-amilase of different origin

The search for the effective and safe a-glucosidase and alpha-amylase inhibitors from Actinomycetaceae being antidiabetic agents is actual problem. Twenty one Streptomyces spp. of soil samples collected from different places of China were screened for the ability to produce this kind of inhibitory activities. Fermentation broth of isolated strains had absorbance between 350-190 nm. The Streptomyces strains PW003, ZG636, and ZG731 were characterized by special absorption at 280, 275, and 400 nm, respectively. Ten of the collected actinomycete strains had the ability to inhibit alpha-glucosidase or/and alpha-amylase and the fermentation broth of the same strain had inhibitory activity varied greatly depending on the enzyme source. In the process to screen the leading compounds used as antidiabetic agents, human alpha-glucosidase and alpha-amylase were revealed as the best used in trail compared with the same enzymes from other sources. Active alpha-glucosidase inhibitor was isolated from Streptomyces strain PW638 fermentation broth and identified as acarviostatin 103 by MS and N MR spectrometry. Its IC50 value was 1.25 and 12.23 microg/mL against human intestinal N-terminal maltase-glucoamylase and human pancreatic alpha-amylase, respectively.