Objectives: To explore a method of surface electrocardiogram for assessing cardiac dysfunction in patients with old myocardial infarction. Methods: 1000 patients with old myocardial infarction in Anzhen hospital were analyzed retrospectively. The planar QRS-T angle was calculated automatically according to QRS-wave and T-wave vectors by the electrocardiogram machine. Results: Among these 1000 patients, 822 (82.2%) were male and 178 (17.8%) were female, the mean age was 59.3±10.5 years (34~89 years). The average planar QRS-T angle was 88.5±50.6°. The planar QRS-T angle and LVEF was negative correlation (r=-0.406, p<0.01), the lower the LVEF, the better the relationship with planar QRS-T angle. QRS-T angle>90° had optimal sensitivity and specificity (76%, 74%) in diagnosis of cardiac dysfunction. Conclusion: The planar QRS-T angle and LVEF of patients with old myocardial infarction is negative correlation, the larger the planar QRS-T angle, the lower the LVEF. The planar QRS-T angle may be an easier and more feasible index for assessing cardiac dysfunction in patients with old myocardial infarction.
Planar QRS-T angle; old myocardial infarction; cardiac dysfunction
Somatic mutation of the tumor suppressor gene LKB1 occurs frequently in lung cancer where it causes tumor progression and metastasis, but the underlying mechanisms remain mainly unknown. Here, we show that the oncogene NEDD9 is an important downstream mediator of lung cancer progression evoked by LKB1 loss. In de novo mouse models, RNAi-mediated silencing of Nedd9 inhibited lung tumor progression, whereas ectopic NEDD9 expression accelerated this process. Mechanistically, LKB1 negatively regulated NEDD9 transcription by promoting cytosolic translocation of CRTC1 from the nucleus. Notably, ectopic expression of either NEDD9 or CRTC1 partially reversed the inhibitory function of LKB1 on metastasis of lung cancer cells. In clinical specimens, elevated expression of NEDD9 was associated with malignant progression and metastasis. Collectively, our results decipher the mechanism through which LKB1 deficiency promotes lung cancer progression and metastasis, and provide a mechanistic rationale for therapeutic attack of these processes.
Background: To explore an optimal management of perioperative anticoagulation for patients with long-term warfarin therapy after valve replacement during the perioperative of pacemaker implantation. Methods: We retrospectively reviewed consecutive patients undergoing pacemaker implantation who received long-term warfarin therapy after valve replacements at our hospital. They were divided into 3 groups: discontinued group, bridging group and continued group. We analyzed the relationship between different anticoagulation methods during the peri-procedure period and hemorrhage and embolism events. Results: 132 patients were enrolled. There was no significant difference concerning the mean age, sex, concomitant diseases, atrial fibrillation and whether performed pacemaker replacement among 3 groups. The incidence of hematomas was irrespective of the perioperative anticoagulation strategy used (P = 0.125). A strategy involving bridging anticoagulation with therapeutic-dose heparin was associated with an incidence of wound errhysis (P = 0.008). There was no thromboembolism event in these three groups. Conclusion: The results showed that there was no significant difference in hematoma rate among continued group, discontinued group, and bridging group, but there was much more wound errhysis in the bridging group. Also, the study shows that if warfarin is continued, it will not increase the risk of bleeding when the International Normalized Ratio (INR) is around 1.7 during the procedure.
Cardiology; pacemaker; anticoagulation; valve replacement; hematomas; thromboembolism
The present study reports a human case of cutaneous gnathostomiasis with recurrent migratory nodule and persistent eosinophilia in China. A 52-year-old woman from Henan Province, central China, presented with recurrent migratory reddish swelling and subcutaneous nodule in the left upper arm and on the back for 3 months. Blood examination showed eosinophila (21.2%), and anti-sparganum antibodies were positive. Skin biopsy of the lesion and histopathological examinations revealed dermal infiltrates of eosinophils but did not show any parasites. Thus, the patient was first diagnosed as sparganosis; however, new migratory swellings occurred after treatment with praziquantel for 3 days. On further inquiring, she recalled having eaten undercooked eels and specific antibodies to the larvae of Gnathostoma spinigerum were detected. The patient was definitely diagnosed as cutaneous gnathostomiasis caused by Gnathostoma sp. and treated with albendazole (1,000 mg/day) for 15 days, and the subsequent papule and blister developed after the treatment. After 1 month, laboratory findings indicated a reduced eosinophil count (3.3%). At her final follow-up 18 months later, the patient had no further symptoms and anti-Gnathostoma antibodies became negative. Conclusively, the present study is the first report on a human case of cutaneous gnathostomiasis in Henan Province, China, based on the past history (eating undercooked eels), clinical manifestations (migratory subcutaneous nodule and persistent eosinophilia), and a serological finding (positive for specific anti-Gnathostoma antibodies).
Gnathostoma spinigerum; gnathostomiasis; migratory subcutaneous nodule; serodiagnosis; albendazole; China
We report a method to promote photoluminescence emission in graphene materials by enhancing carrier scattering instead of directly modifying band structure in multilayer reduced graphene oxide (rGO) nanospheres. We intentionally curl graphene layers to form nanospheres by reducing graphene oxide with spherical polymer templates to manipulate the carrier scattering. These nanospheres produce hot-carrier luminescence with more than ten-fold improvement of emission efficiency as compared to planar nanosheets. With increasing excitation power, hot-carrier luminescence from nanospheres exhibits abnormal spectral redshift with dynamic feature associated to the strengthened electron-phonon coupling. These experimental results can be well understood by considering the screened Coulomb interactions. With increasing carrier density, the reduced screening effect promotes carrier scattering which enhances hot-carrier emission from such multilayer rGO nanospheres. This carrier-scattering scenario is further confirmed by pump-probe measurements.
Primary restless leg syndrome (RLS) is a common sensory-motor disorder that is characterized by an irresistible urge to move the limbs and unpleasant sensations in the legs, which affects 1.9%–4.6% adults. Pramipexole, a potent dopamine D2/3 agonist, is recommended as “effective” in the short-term and “possibly effective” in the long-term treatment of primary RLS in the European guidelines on management of RLS. In this meta-analysis, we summarized the efficacy and tolerability of pramipexole in treatment for primary RLS. Results of this meta-analysis showed a favorable effect of pramipexole versus placebo on RLS symptoms (mean change on International RLS Study Group Rating Scale [IRLS] score: mean difference [MD] = −5.96; 95% confidence interval [CI]: −7.79 to −4.41, P < 0.00001) and sleep quality (pooled standard mean difference [SMD] = −0.48, 95% CI: −0.61 to −0.35, P < 0.00001). Nausea (relative risk [RR] = 2.68, 95% CI: 1.82 to 3.95, P < 0.001) and fatigue (RR = 1.82, 95% CI: 1.14 to 2.93, P = 0.013) were the most common adverse events, but, by and large, pramipexole was well-tolerated in patients with primary RLS. Nevertheless, long-term studies and more evidence of head-to-head comparisons of pramipexole with other dopamine agonists, anticonvulsants, and levodopa are needed.
restless legs syndrome; pramipexole; meta-analysis
T-helper (Th) 22 and Th17 cells are involved in the pathogenesis of autoimmune diseases. However, their roles in the pathogenesis of Graves’disease (GD) are unclear. This study is aimed at examining the frequency of peripheral blood Th22, Th17, and Th1 cells and the levels of plasma IL-22, IL-17, and IFN-γ in patients with GD. A total of 27 patients with new onset GD and 27 gender- and age-matched healthy controls (HC) were examined for the frequency of peripheral blood Th22, Th17, and IFN-γ cells by flow cytometry. The concentrations of plasma IL-22, IL-17, and IFN-γ were examined by enzyme-linked immunosorbent assay. The levels of serum TSHR antibodies (A-TSHR), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) were examined by radioimmunoassay and chemiluminescent assay, respectively. The levels of serum TSAb were examined by enzyme-linked immunosorbent assay. In comparison with those in the HC, significantly elevated percentages of Th22 and Th17 cells, but not Th1 cells, and increased levels of plasma IL-22 and IL-17, but not IFN-γ, were detected in GD patients (P<0.0001, for both). The percentages of both Th22 and Th17 cells and the levels of plasma IL-22 and IL-17 were correlated positively with the levels of serum TSAb in GD patients (r = 0.7944, P<0.0001; r = 0.8110, P<0.0001; r = 0.7101, p<0.0001; r = 0.7407, p<0.0001, respectively). Th22 and Th17 cells may contribute to the pathogenesis of GD.
Two dimension (2D) layered molybdenum disulfide (MoS2) has emerged as a promising candidate for the anode material in lithium ion batteries (LIBs). Herein, 2D MoSx (2 ≤ x ≤ 3) nanosheet-coated 1D multiwall carbon nanotubes (MWNTs) nanocomposites with hierarchical architecture were synthesized via a high-throughput solvent thermal method under low temperature at 200°C. The unique hierarchical nanostructures with MWNTs backbone and nanosheets of MoSx have significantly promoted the electrode performance in LIBs. Every single MoSx nanosheet interconnect to MWNTs centers with maximized exposed electrochemical active sites, which significantly enhance ion diffusion efficiency and accommodate volume expansion during the electrochemical reaction. A remarkably high specific capacity (i.e., > 1000 mAh/g) was achieved at the current density of 50 mA g−1, which is much higher than theoretical numbers for either MWNTs or MoS2 along (~372 and ~670 mAh/g, respectively). We anticipate 2D nanosheets/1D MWNTs nanocomposites will be promising materials in new generation practical LIBs.
Ophiostoma piceae is a wood-staining fungus that grows in the sapwood of conifer logs and lumber. We sequenced its genome and analyzed its transcriptomes under a range of growth conditions. A comparison with the genome and transcriptomes of the mountain pine beetle-associated pathogen Grosmannia clavigera highlights differences between a pathogen that colonizes and kills living pine trees and a saprophyte that colonizes wood and the inner bark of dead trees.
We assembled a 33 Mbp genome in 45 scaffolds, and predicted approximately 8,884 genes. The genome size and gene content were similar to those of other ascomycetes. Despite having similar ecological niches, O. piceae and G. clavigera showed no large-scale synteny. We identified O. piceae genes involved in the biosynthesis of melanin, which causes wood discoloration and reduces the commercial value of wood products. We also identified genes and pathways involved in growth on simple carbon sources and in sapwood, O. piceae’s natural substrate. Like the pathogen, the saprophyte is able to tolerate terpenes, which are a major class of pine tree defense compounds; unlike the pathogen, it cannot utilize monoterpenes as a carbon source.
This work makes available the second annotated genome of a softwood ophiostomatoid fungus, and suggests that O. piceae’s tolerance to terpenes may be due in part to these chemicals being removed from the cells by an ABC transporter that is highly induced by terpenes. The data generated will provide the research community with resources for work on host-vector-fungus interactions for wood-inhabiting, beetle-associated saprophytes and pathogens.
Ophiostoma piceae; Genome; Transcriptome; Wood-staining fungus; Saprobe
Cardiac injury is a common pathological change frequently accompanied by diabetes mellitus. Recently, some evidence indicated that calcium-sensing receptor (CaSR) expressed in the cardiac tissue. However, the functional role of CaSR in diabetic cardiac injury remains unclear. The present study was designed to investigate the relationship between CaSR activation and diabetes-induced cardiac injury. Diabetic model was successfully established by administration of streptozotocin (STZ) in vivo, and cardiomyocyte injury was simulated by 25.5 mM glucose in vitro. Apoptotic rate, intracellular calcium concentration ([Ca2+]i) and the expression of Bcl-2, Bax, extracellular signal-regulated protein kinase (ERK), c-Jun NH2-terminal protein kinase (JNK), and p38 were examined. We demonstrated a significant increase in left ventricular end-diastolic pressure (LVEDP) as well as decrease in maximum rate of left ventricular pressure rise and fall (±dp/dtmax), and left ventricular systolic pressure (LVSP), apoptosis of cardiomyocytes was also observed by TUNEL staining. In vitro, 25.5 mM glucose-induced apoptosis was detected by flow cytometry in neonatal rat cardiomyocytes. Further results showed that 25.5 mM glucose significantly increased [Ca2+]i, up-regulated the expression of Bax, P-ERK and P-JNK, and suppressed Bcl-2 expression. However, the above deleterious changes were further confirmed when co-treatment with CaSR agonist GdCl3 (300 µM). But the effects of GdCl3 were attenuated by 10 µM NPS-2390, a specific CaSR inhibitor. When CaSR was silence by siRNA transfection, the effects of high glucose were inhibited. These results suggest that CaSR activation could lead to the apoptosis of cardiomyocytes in diabetic cardiac injury through the induction of calcium overload, the activation of the mitochondrial, and mitogen-activated protein kinase pathway.
Sexual reproduction in fungi is regulated by the mating-type (MAT) locus where recombination is suppressed. We investigated the evolution of MAT loci in eight fungal species belonging to Grosmannia and Ophiostoma (Sordariomycetes, Ascomycota) that include conifer pathogens and beetle symbionts. The MAT1-2 idiomorph/allele was identified from the assembled and annotated Grosmannia clavigera genome, and the MAT locus is flanked by genes coding for cytoskeleton protein (SLA) and DNA lyase. The synteny of these genes is conserved and consistent with other members in Ascomycota. Using sequences from SLA and flanking regions, we characterized the MAT1-1 idiomorph from other isolates of G. clavigera and performed dotplot analysis between the two idiomorphs. Unexpectedly, the MAT1-2 idiomorph contains a truncated MAT1-1-1 gene upstream of the MAT1-2-1 gene that bears the high-mobility-group domain. The nucleotide and amino acid sequence of the truncated MAT1-1-1 gene is similar to its homologous copy in the MAT1-1 idiomorph in the opposite mating-type isolate, except that positive selection is acting on the truncated gene and the alpha(α)-box that encodes the transcription factor has been deleted. The MAT idiomorphs sharing identical gene organization were present in seven additional species in the Ophiostomatales, suggesting that the presence of truncated MAT1-1-1 gene is a general pattern in this order. We propose that an ancient unequal recombination event resulted in the ancestral MAT1-1-1 gene integrated into the MAT1-2 idiomorph and surviving as the truncated MAT1-1-1 genes. The α-box domain of MAT1-1-1 gene, located at the same MAT locus adjacent to the MAT1-2-1 gene, could have been removed by deletion after recombination due to mating signal interference. Our data confirmed a 1:1 MAT/sex ratio in two pathogen populations, and showed that all members of the Ophiostomatales studied here including those that were previously deemed asexual have the potential to reproduce sexually. This ability can potentially increase genetic variability and can enhance fitness in new, ecological niches.
heterothallism; homothallism; mating system evolution; outcrossing; selfing
Salmonella are important human and animal pathogens. Though highly related, the Salmonella lineages may be strictly adapted to different hosts or cause different diseases, from mild local illness like gastroenteritis to fatal systemic infections like typhoid. Therefore, rapid and accurate identification of Salmonella is essential for timely and correct diagnosis of Salmonella infections. The current identification methods such as 16S rRNA sequencing and multilocus sequence typing are expensive and time consuming. Additionally, these methods often do not have sufficient distinguishing resolution among the Salmonella lineages.
We compared 27 completely sequenced Salmonella genomes to identify possible genomic features that could be used for differentiation of individual lineages. We concatenated 2372 core genes in each of the 27 genomes and constructed a neighbor-joining tree. On the tree, strains of each serotype were clustered tightly together and different serotypes were unambiguously separated with clear genetic distances, demonstrating systematic genomic divergence among the Salmonella lineages. We made detailed comparisons among the 27 genomes and identified distinct sets of genomic differences, including nucleotide variations and genomic islands (GIs), among the Salmonella lineages. Two core genes STM4261 and entF together could unambiguously distinguish all Salmonella lineages compared in this study. Additionally, strains of a lineage have a common set of GIs and closely related lineages have similar sets of GIs.
Salmonella lineages have accumulated distinct sets of mutations and laterally acquired DNA (e.g., GIs) in evolution. Two genes entF and STM4261 have diverged sufficiently among the Salmonella lineages to be used for their differentiation. Further investigation of the distinct sets of mutations and GIs will lead to novel insights into genomic evolution of Salmonella and greatly facilitate the elucidation of pathogeneses of Salmonella infections.
Xylanase is an important component of hemicellulase enzyme system. Since it plays an important role in the hydrolysis of hemicellulose into xylooligosaccharides (XOs), high thermostable xylanase has been the focus of much recent attention as powerful enzyme as well as in the field of biomass utilization.
A xylanase gene (xyn10A) with 3,474 bp was cloned from the extremely thermophilic bacterium Thermotoga thermarum that encodes a protein containing 1,158 amino acid residues. Based on amino acid sequence homology, hydrophobic cluster and three dimensional structure analyses, it was attested that the xylanase belongs to the glycoside hydrolase (GH) families 10 with five carbohydrate binding domains. When the xylanase gene was cloned and expressed in Escherichia coli BL21 (DE3), the specific enzyme activity of xylanase produced by the recombinant strain was up to 145.8 U mg-1. The xylanase was optimally active at 95°C, pH 7.0. In addition, it exhibited high thermostability over broad range of pH 4.0-8.5 and temperature 55-90°C upon the addition of 5 mM Ca2+. Confirmed by Ion Chromatography System (ICS) analysis, the end products of the hydrolysis of beechwood xylan were xylose, xylobiose, xylotriose, xylotetraose, xylopentaose and xylohexaose.
The xylanase from T. thermarum is one of the hyperthermophilic xylanases that exhibits high thermostability, and thus, is a suitable candidate for generating XOs from cellulosic materials such as agricultural and forestry residues for the uses as prebiotics and precursors for further preparation of furfural and other chemicals.
Xylanase; Xylan; Thermostability; Beechwood; Oat spelt; Birchwood
The current study sought to assess the role of paraaortic lymphadenectomy (LNE) in females with endometrial cancer. A retrospective analysis of patients diagnosed with endometrial cancer of stage IA to II preoperatively, between 2009 and 2011 was conducted. Patients were included who had suffered from endometrial cancer without preoperative adjuvant therapy and who underwent hysterectomy plus systematic pelvic LNE and paraaortic LNE by laparoscopy or laparotomy. A total of 54 patients who underwent surgery for preoperative endometrial cancer were selected. All patients underwent LNE. The incidences of pelvic and paraaortic lymph node metastases were 11.1% (6/54) and 7.4% (4/54), with a total positive lymph node rate of 14.8% (8/54). In addition, among the 8 positive cases, 5 patients underwent laparotomy and 3 underwent laparoscopy; 3 cases were classified as stage I and 5 as stage II preoperatively. Of these, 7 patients were identified with pathology-related risk factors, including low differentiation or clear cell adenocarcinoma postoperatively. Discordance of pathological differentiation between the pre- and postoperative stages reached 57.1% (4/7). The results revealed the high occurrence of positive lymph nodes in endometrial cancer which demonstrate the importance of systematic LNE. Additonally, no severe complications were caused by LNE besides lymph cysts. In summary, it is neccesary to perform LNE, particularly the removal of the paraaortic lymph node, in patients with endometrial cancers in order to improve postoperative therapy. Laparoscopy has similar surgical effects as laparotomy, but has a number of advantages.
lymphadenectomy; endometrial cancer; paraaortic
To elucidate the phytohormonal basis of the feedback regulation of leaf senescence induced by potassium (K) deficiency in cotton (Gossypium hirsutum L.), two cultivars contrasting in sensitivity to K deficiency were self- and reciprocally grafted hypocotyl-to-hypocotyl, using standard grafting (one scion grafted onto one rootstock), Y grafting (two scions grafted onto one rootstock), and inverted Y grafting (one scion grafted onto two rootstocks) at the seedling stage. K deficiency (0.03mM for standard and Y grafting, and 0.01mM for inverted Y grafting) increased the root abscisic acid (ABA) concentration by 1.6- to 3.1-fold and xylem ABA delivery rates by 1.8- to 4.6-fold. The K deficiency also decreased the delivery rates of xylem cytokinins [CKs; including the zeatin riboside (ZR) and isopentenyl adenosine (iPA) type] by 29–65% and leaf CK concentration by 16–57%. The leaf ABA concentration and xylem ABA deliveries were consistently greater in CCRI41 (more sensitive to K deficiency) than in SCRC22 (less sensitive to K deficiency) scions under K deficiency, and ZR- and iPA-type levels were consistently lower in the former than in the latter, irrespective of rootstock cultivar or grafting type, indicating that cotton shoot influences the levels of ABA and CKs in leaves and xylem sap. Because the scions had little influence on phytohormone levels in the roots (rootstocks) of all three types of grafts and rootstock xylem sap (collected below the graft union) of Y and inverted Y grafts, it appears that the site for basipetal feedback signal(s) involved in the regulation of xylem phytohormones is the hypocotyl of cotton seedlings. Also, the target of this feedback signal(s) is more likely to be the changes in xylem phytohormones within tissues of the hypocotyl rather than the export of phytohormones from the roots.
Abscisic acid; cotton; cytokinins; feedback regulation; potassium deficiency
High-affinity nitrite influx into mycelia of Aspergillus nidulans has been characterized by use of 13NO2−, giving average Km and Vmax values of 48 ± 8 μM and 228 ± 49 nmol mg−1 dry weight (DW) h−1, respectively. Kinetic analysis of a plot that included an additional large number of low-concentration fluxes gave an excellent monophasic fit (r2 = 0.96), with no indication of sigmoidal kinetics. Two-dimensional (2D) and three-dimensional (3D) models of AnNitA are presented, and the possible roles of conserved asparagine residues N122 (transmembrane domain 3 ]Tm 3]), N173 (Tm 4), N214 (Tm 5), and N246 (Tm 6) are discussed.
In the rapid development of nanoscience and nanotechnology, many researchers have discovered that metal oxide nanoparticles have very useful pharmacological effects. Cuprous oxide nanoparticles (CONPs) can selectively induce apoptosis and suppress the proliferation of tumor cells, showing great potential as a clinical cancer therapy. Treatment with CONPs caused a G1/G0 cell cycle arrest in tumor cells. Furthermore, CONPs enclosed in vesicles entered, or were taken up by mitochondria, which damaged their membranes, thereby inducing apoptosis. CONPs can also produce reactive oxygen species (ROS) and initiate lipid peroxidation of the liposomal membrane, thereby regulating many signaling pathways and influencing the vital movements of cells. Our results demonstrate that CONPs have selective cytotoxicity towards tumor cells, and indicate that CONPs might be a potential nanomedicine for cancer therapy.
nanomedicine; selective cytotoxicity; apoptosis; cell cycle arrest; mitochondrion-targeted nanomaterials
Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Many studies suggest that age-related maculopathy susceptibility 2 (ARMS2) is a second major susceptibility gene for AMD. At present, there is no functional information on this gene. Therefore, the purpose of the present study was to detect the expression of ARMS2 in retinal pigment epithelium (RPE) cells and to investigate the effect of ARMS2 on the phagocytosis function of RPE cells.
Immunofluorescence and reverse transcriptase PCR were used to demonstrate the presence and location of ARMS2 in ARPE-19 (human retinal pigment epithelial cell line, ATCC, catalog No.CRL-2302) cells. siRNA was used to knock down ARMS2 mRNA, and the effects of the knockdown on the phagocytosis function of the ARPE-19 cells were evaluated via Fluorescence Activated Cell Sorting (FACS).
ARMS2 was present in ARPE-19 cells, localized in the cytosol of the perinuclear region. The expression of ARMS2 mRNA (messenger RNA) in ARPE-19 cells transfected with ARMS2-siRNA (small interfering RNA, 0.73±0.08) was decreased compared with normal cells (1.00±0.00) or with cells transfected with scrambled siRNA (0.95±0.13) (P<0.05). After incubation of RPE cells with a latex beads medium for 12, 18, or 24 hours, the fluorescence intensities were 38.04±1.02, 68.92±0.92, and 78.00±0.12 in the ARMS2-siRNA-transfected groups, respectively, and 77.98±5.43, 94.87±0.60, and 98.30±0.11 in the scrambled siRNA-transfected groups, respectively. The fluorescent intensities of the same time points in the two groups were compared using Student's t-test, and the p values were all less than 0.001 at the three different time points.
There is endogenous expression of ARMS2 in ARPE-19 cells. ARMS2 plays a role in the phagocytosis function of RPE cells, and this role may be one of the mechanisms that participates in the development of AMD.
age-related maculopathy susceptibility 2; age-related macular degeneration; retinal pigment epithelium; phagocytosis
Membrane type-1 matrix metalloproteinase (MT1-MMP) is a key member of the matrix metalloproteinase (MMP) family. It participates in pericellular proteolysis of extracellular matrix (ECM) macromolecules and is essential for many biological and pathological processes, such as tumor development, angiogenesis and metastasis. A ligand that specifically binds to MT1-MMP may facilitate the labeling of this molecule, allow imaging at the cellular and organism levels, and provide a means for targeted drug delivery specific to MT1-MMP. A non-substrate MT1-MMP binding peptide was identified by screening a Ph. D.™ - 12 phage display peptide library and conjugated with near-infrared fluorescent (NIRF) dye Cy5.5 for tumor imaging. Peptide HWKHLHNTKTFL (denoted as MT1-AF7p) showed high MT1-MMP binding affinity. Computer modeling verified that MT1-AF7p binds to the MT-loop region of MT1-MMP and interacts with MT1-MMP through hydrogen bonding and hydrophobic interactions. MDA-MB-435 xenografts with high MT1-MMP expression had significantly higher tumor accumulation and better tumor contrast than the low MT1-MMP expressing A549 xenografts after intravenous injection of Cy5.5-MT1-AF7p. A novel non-substrate affinity peptide MT1-AF7p was found for MT1-MMP high affinity and specificity. Using NIRF imaging, we have demonstrated specific targeting of MT1-AF7p to MT1-MMP-expressing tumors. Thus, MT1-AF7p is an important tool for noninvasive monitoring of MT1-MMP expression in tumors, and it shows great potential as an imaging agent for MT1-MMP – positive tumors.
matrix metalloproteinase; MT1-MMP (MMP-14); phage display peptide library; near-infrared fluorescence optical imaging
A fundamental property of cortical neurons is the capacity to exhibit adaptive changes or plasticity. Whether adaptive changes in cortical responses are accompanied by changes in synchrony between individual neurons and local population activity in sensory cortex is unclear. This issue is important as synchronized neural activity is hypothesized to play an important role in propagating information in neuronal circuits. Here we show that rapid adaptation (300 ms) to a stimulus of fixed orientation modulates the strength of oscillatory neuronal synchronization in macaque visual cortex (area V4) and influences the neurons’ ability to distinguish small changes in stimulus orientation. Specifically, rapid adaptation increases the synchronization of individual neuronal responses with local population activity in the gamma frequency band (30–80 Hz). In contrast to previous reports that gamma synchronization is associated with an increase in firing rates in V4, we found that the post-adaptation increase in gamma synchronization is associated with a decrease in neuronal responses. The increase in gamma-band synchronization after adaptation is functionally significant as it is correlated with an improvement in neuronal orientation discrimination performance. Thus, adaptive synchronization between the spiking activity of individual neurons and their local population can enhance temporally-insensitive, rate-based-coding schemes for sensory discrimination.
Determine cyclin-dependent kinase inhibitor 2A (p16Ink4a) and polycomb ring finger oncogene (Bmi1) expression in corneal endothelium samples from different age groups and test whether the expression of p16INK4a and Bmi1 are associated with endothelial cellular senescence in human cornea.
Samples were selected from an eyebank of healthy human corneal endothelial cells (HCECs). Donor human corneas were divided into three age-groups: age ≤30 years, 30–50 years and ≥50 years. The expression of p16INK4a and Bmil were analyzed by real-time PCR, immunohistochemistry, and immunofluorescence.
Through real-time PCR, we detected less than threefold decreases in Bmi1 expression and greater than fivefold increases in p16INK4a expression associated with aging. Bmi1 expression was significantly down-regulated with increasing donor age. The number of p16INK4a-positive cells was significantly higher and the number of Bmi1-positive cells was significantly lower in older donors compared to the younger age groups. Our immunohistochemistry experiments showed that the expression of p16INK4a in older donors was stronger than that in younger donors and the expression of Bmi1 in older donors was weaker than that in younger donors. Results from both the immunohistochemistry and real-time PCR experiments confirmed increased expression of p16INK4a and decreased expression of Bmi1 with age in HCECs. Additionally, the results of immunofluorescence double-staining for p16INK4a and Bmi1 further validated the immunocytochemistry and real-time PCR results.
Our data are the first to demonstrate that high expression of p16INK4a and low expression of Bmi1 are associated with endothelial cellular senescence in human cornea. Our findings are not just for cornea transplantation but also for a better understanding of the cornea senescence and the process of aging in this sepcific human organ.
Inappropriate contact lens (CL) use and care often lead to corneal neovascularization (corneal NV). We used mouse eyes which wore CL as the animal model to assess the reason for corneal NV with CL wear. The similar and overlapping activity of vascular endothelial growth factor (VEGF) and the potent angiogenic hypoxia-inducible factor 1α (HIF-1α) called for a study of the temporal relationship in the expression of these two autocoids. We determined the time dependent expression of HIF-1α and correlated it to that of VEGF expression in the mouse model of closed eye with CL wear.
Mouse eyes were fitted with CL followed by a silk suture tarsorrhaphy. The anterior surface was analyzed at 4, 7, and 10 days after tarsorrhaphy by slit lamp and corneal NV. HIF-1α and VEGF levels were measured by reverse transcription PCR, western blotting and immunofluorescence with specific primers and antibodies. We used shRNA targeting HIF-1α to substantiate the link between HIF-1α, VEGF expression, and angiogenesis in the CL wear model.
Corneal NV scores increased in a time dependent manner in the model of closed eye CL induced hypoxic injury. Corneal epithelial HIF-1α and VEGF expression increased in a time dependent manner. The prolonged hypoxic state brought by closed eye CL wear induced a time dependent neovascular response which was significantly attenuated by HIF-1α specific shRNA but not by nonspecific shRNA. Both HIF-1α and VEGF levels were reduced significantly in corneal homogenates from eyes treated with the HIF-1α specific shRNA.
The present study documented the increased expression of HIF-1α in the corneal epithelium during CL wear. It also demonstrated the presence of VEGF in the corneal epithelium and its increased expression in this model. Altogether, the results of this study raised the possibility of interaction between HIF-1α and VEGF, in mediating the neovascularization response induced by the prolonged hypoxic state brought about by closed eye CL wear. The results strongly implicated corneal HIF-1α as a component of the inflammatory and neovascular cascade initiated by hypoxic and further suggested that HIF-1α was a proximal regulator of VEGF expression in this model.