MicroRNA miR-93 promotes tumor growth and angiogenesis by targeting integrin-β8

It has been reported that the miR-106b∼25 cluster, a paralog of the miR-17∼92 cluster, possesses oncogenic activities. However, the precise role of each microRNA (miRNA) in the miR-106b∼25 cluster is not yet known. In this study, we examined the function of miR-93, one of the microRNAs within the miR-106b∼25 cluster, in angiogenesis and tumor formation. We found that miR-93 enhanced cell survival, promoted sphere formation and augmented tumor growth. Most strikingly, when miR-93-overexpressing U87 cells were co-cultured with endothelial cells, they supported endothelial cell spreading, growth, migration and tube formation. In vivo studies revealed that miR-93-expressing cells induced blood vessel formation, allowing blood vessels to extend to tumor tissues in high densities. Angiogenesis promoted by miR-93 in return facilitated cell survival, resulting in enhanced tumor growth. We further showed that integrin-β8 is a target of miR-93. Higher levels of integrin-β8 are associated with cell death in tumor mass and in human glioblastoma. Silencing of integrin-β8 expression using small interfering RNA promoted cell proliferation, whereas ectopic expression of integrin-β8 decreased cell growth. These findings showed that miR-93 promotes tumor growth and angiogenesis by suppressing, at least in part, integrin-β8 expression. Our results suggest that inhibition of miR-93 function may be a feasible approach to suppress angiogenesis and tumor growth.

Disclosure of HIV-positive serostatus to sexual partners and associated factors in southern China

In light of an increased push for disclosure of HIV-positive serostatus to sexual partners (partner disclosure, PD) in China as reflected by national and local policies, the objective of this study was to determine the proportion and evaluate associated factors of PD among people living with HIV/AIDS (PLWHA) in HIV/AIDS high-risk areas in southern China. Of the 946 HIV-positive individuals, the proportion of those who disclosed positive serostatus results to their sexual partners was 90.2% (625/693). Variables independently associated with non-disclosure included testing in Guangxi province (adjusted relative ratio [ARR] = 0.33), becoming infected with HIV via injecting drug use (IDU) transmission (ARR = 0.32), having not reported discussing disclosure with health department staff during post-test counselling (ARR = 0.41) and having a sexual relationship of ≤2 years' duration (ARR = 0.31). This study also identified a relatively larger differential between the proportion of disclosure to regular partners and the proportion of disclosure to casual partners (94.8% versus 13.0%) in comparison with other studies. Findings from this study may aid policies for future consideration.

An improved strip FRAP method for estimating diffusion coefficients: correcting for the degree of photobleaching

Fluorescence recovery after photobleaching is a widely established method for the estimation of diffusion coefficients, strip bleaching with an associated recovery curve analysis being one of the simplest techniques. However, its implementation requires near 100% bleaching in the region of interest with negligible fluorescence loss outside, both constraints being hard to achieve concomitantly for fast diffusing molecules. We demonstrate that when these requirements are not met there is an error in the estimation of the diffusion coefficient D, either an under- or overestimation depending on which assumption is violated the most. We propose a simple modification to the recovery curve analysis incorporating the concept of the relative bleached mass m giving a revised recovery time parametrization tau=m(2)w(2)/4piD for a strip of width w. This modified model removes the requirement of 100% bleaching in the region of interest and allows for limited diffusion of the fluorophore during bleaching. We validate our method by estimating the (volume) diffusion coefficient of FITC-labelled IgG in 60% glycerol solution, D= 4.09 +/- 0.21 microm(2) s(-1), and the (surface) diffusion coefficient of a green-fluorescent protein-tagged class I MHC protein expressed at the surface of a human B cell line, D= 0.32 +/- 0.03 microm(2) s(-1) for a population of cells.

Properties of hepatitis C virus minigenome containing mutated 5'UTR region and luciferase transgene

Sequences at the 3'UTR of Hepatitis C virus (HCV) negative-strand (-)RNA play an important role in the initiation of positive-strand (+)RNA synthesis. However, the underlying mechanism in cellular context is still unclear. In this report, we designed several cDNA-based HCV-like minigenomes containing different mutations at the 5'UTR of (+)RNA. These (+)RNAs transcribed from the minigenomes in vitro were transfected into HCV replicon cells for producing (-)RNAs with deletions of different stem loops (SL) at the 3'-end. The results showed that expression of the antisense transgene from minigenome increased, when the minigenome containing deletion of SL-C1+D1+E1 at the 3'-end of (-)RNA was transfected into the HCV replicon cells compared to that of the full minigenome. The expression of the transgene from minigenome decreased using other mutant minigenomes containing deletions SL-A1, SL-A1+B1, and SL-A1+B1+C1 at the 3'-end of (-)RNA. Finally, the transgene from SL-C1+D1+E1 of (-)RNA using CMV promoter-driven minigenome was expressed at higher level than full minigenome in HCV replicon cell lines. These results indicated that the region of (-)RNA interacting with HCV replicase may locate in the SL-C1+D1+E1 region of (-)RNA.

KEYWORDS

Hepatitis C virus; minigenome; RNA dependent RNA polymerase; replication.

The T helper type 17/regulatory T cell imbalance in patients with acute Kawasaki disease

The study is designed to investigate the changes and roles of T helper type 17/regulatory T cells (Th17/T(reg) ) in the immunological pathogenesis of Kawasaki disease (KD). In addition, we explore the alteration and significance of Th17 cells in patients with intravenous immune globulin-resistant KD. Real-time polymerase chain reaction (PCR) was used to evaluate the mRNA levels of interleukin (IL)-17A/F, retinoic acid-related orphan receptor (ROR)-γt and forkhead box P3 (FoxP3) in CD4-positive cells. The proportions of Th17 cells and CD4(+) CD25(+) FoxP3(high) T(regs) were analysed by flow cytometry. Plasma cytokine [IL-17A, IL-6, IL-23 and transforming growth factor (TGF)-β] concentrations were measured by sandwich enzyme-linked immunosorbent assay. Our data demonstrate that Th17 proportions and expression levels of cytokines (IL-17, IL-6 and IL-23) and transcription factors (IL-17A/F, ROR-γt) were up-regulated significantly, while T(reg) proportions and expression levels of T(reg ) transcription factor (FoxP3) were down-regulated significantly in children with acute KD (P<0·01). Compared with the sensitive group, the Th17 proportions were up-regulated significantly during the acute phase in immune globulin-resistant KD (P < 0·01). The plasma IL-17A, IL-6 and IL-23 concentrations in patients with KD were significantly higher compared with the concentrations in normal controls (NC) and infectious disease (ID). Plasma TGF-β concentrations were markedly lower in the KD group than the NC and ID groups (P < 0·05). These results suggest that Th17/T(reg) cells imbalance exists in the patients with KD. Th17/T cells imbalance may be important factors causing disturbed immunological function and resulting in immunoglobulin-resistant KD.

Silver square nanospirals mimic optical properties of U-shaped metamaterials

We present a study of the optical properties of three-armed square nanospirals made of silver and realized as nanostructured thin films with Glancing Angle Deposition. Calculation of current flows in the nanospirals show excited resonant modes resembling those observed in U-shaped resonators. Four principal resonances were determined: near 200 THz and 480 THz for one polarization and 250 THz and 650 THz for the polarization orthogonal to the first one. In particular, a mode with anti-parallel current flow in opposite arms, associated with the observed resonance near 650 THz, indicates the existence of a magnetic-like resonance in the square nanospiral arrays. The robustness of the resonances against variations in the structural parameters of the nanospirals was investigated. This study revealed that the main parameter driving the position of the resonances was the overall dimension of the nanospiral, directly related to the length of their arms. Optical properties of a sample were measured by generalized spectroscopic ellipsometry at near-normal incidence, and evidence conversion between polarization states even for light polarized in the plane containing one of the arms in agreement with the numerical study. The measurements compared favorably to the results of the numerical simulations taking into account the disorder in the sample.

Prophylaxis against hepatitis B recurrence posttransplantation using lamivudine and individualized low-dose hepatitis B immunoglobulin

Although the combination of lamivudine (LAM) and high-dose intravenous (IV) hepatitis B immunoglobulin (HBIG) is very effective in preventing hepatitis B virus (HBV) recurrence after liver transplantation (LT), the major limitation of this regimen is its high cost. A more cost-effective, convenient and widely accepted regimen is urgently needed. We evaluated the safety and efficacy of another strategy using LAM and individualized low-dose intramuscular (IM) HBIG. Between May 2002 and December 2009, a total of 254 adult patients undergoing LT for HBV-related benign end-stage liver diseases received this regimen in our center. The mean follow-up of these patients was 41.2 +/- 22.7 months. Their 1-, 3- and 5-year survival rates were 85.3%, 77.4% and 76.4%, respectively, and 1-, 3- and 5-year HBV recurrence rates were 2.3%, 6.2% and 8.2%. Fourteen patients experienced posttransplant HBV recurrence. Pretransplant high viral load and posttransplant prednisone withdrawal time were observed to be associated with recurrence. In conclusion, combination therapy with LAM and individualized low-dose IM HBIG provides a safe and effective prophylaxis against HBV recurrence after LT at about 5% of the cost of conventional high-dose IV HBIG regimens.

Prognostic factors in survival of colorectal cancer patients with synchronous liver metastasis

AIM

To determine the factors affecting the survival in colorectal cancer patients with synchronous liver metastases.

METHOD

A total of 168 patients who had been treated colorectal cancer with synchronous liver metastases at Guangxi Medical University from January 2000 to December 2005 were identified. Criteria studied consisted of gender, age, time of symptoms, primary tumour location, primary tumour circumference, histological type, grade (tumour differentiation), T-status, N-status, large bowel obstruction, type of operation, primary tumour resection, ascities, location, number and diameter of liver lesions, preoperative CEA and chemotherapy. Survival curves were plotted using the Kaplan-Meier method. Multivariate analysis was conducted by Cox regression analysis.

RESULTS

The mean survival time for all patients was 18.71 (SEM = 1.59) months. The 1, 2, 3 and 5-year survival rates were 55.95%, 23.21%, 12.30%, 8.0% respectively. Univariate analysis share of grade (tumour differentiation), N-status, large bowel obstruction, operation, primary tumour resection, location, number and the most diameter of liver lesions, extrahepatic transfer, preoperative CEA level and chemotherapy to be predictors of survival. In the Cox regression analysis, the N-status, large bowel obstruction, operation, diameter of liver lesion and extrahepatic transfer were independent factors related to survival.

CONCLUSION

Tumour differentiation, N-status, bowel obstruction, operation, primary tumour resection, location of liver metastasis, number of liver metastasis, diameter of liver metastasis, extrahepatic transfer, preoperative CEA level and chemotherapy are related to the survival of patients with colorectal cancer and synchronous liver metastases.

Understanding the electric and magnetic response of isolated metaatoms by means of a multipolar field decomposition

We introduce a technique to decompose the scattered near field of two-dimensional arbitrary metaatoms into its multipole contributions. To this end we expand the scattered field upon plane wave illumination into cylindrical harmonics as known from Mie's theory. By relating these cylindrical harmonics to the field radiated by Cartesian multipoles, the contribution of the lowest order electric and magnetic multipoles can be identified. Revealing these multipoles is essential for the design of metamaterials because they largely determine the character of light propagation. In particular, having this information at hand it is straightforward to distinguish between effects that result either from the arrangement of the metaatoms or from their particular design.

Chirped-quasi-periodic structure for quasi-phase-matching

We propose in this paper a chirped-quasi-periodic structure using the projection method. This type of new structure combines the advantages of chirped and quasi-periodic structures, and can be used for both multiple quasi-phase-matching and multiple bandwidths control. Numerical simulation of second-harmonic generation performance is in good agreement with the Fourier spectrum of the structure.

Molecular modeling of human BAD, a pro-apoptotic Bcl-2 family member, integrating glycolysis and apoptosis

Comparison between the BAD complexes indicated that BAD all docks a hydrophobic surface of PKAc regardless of its phosphorylation. PKAc may prevent Bcl-xL from rebinding to BAD by phosphorylating human BAD at Ser118; whereas human BAD is phosphorylated on Ser75 in a BAD-Bcl-xL complex, resulting in the dissociation of BAD.