Oxidative status in the macula densa modulates tubuloglomerular feedback responsiveness in angiotensin II-induced hypertension

AIM

Tubuloglomerular feedback (TGF) is an important mechanism in control of signal nephron glomerular filtration rate. The oxidative stress in the macula densa, primarily determined by the interactions between nitric oxide (NO) and superoxide (O2-), is essential in maintaining the TGF responsiveness. However, few studies examining the interactions between and amount of NO and O2- generated by the macula densa during normal and hypertensive states.

METHODS

In this study, we used isolated perfused juxtaglomerular apparatus to directly measure the amount and also studied the interactions between NO and O2- in macula densa in both physiological and slow pressor Angiotensin II (Ang II)-induced hypertensive mice.

RESULTS

We found that slow pressor Ang II at a dose of 600 ng kg(-1) min(-1) for two weeks increased mean arterial pressure by 26.1 ± 5.7 mmHg. TGF response increased from 3.4 ± 0.2 μm in control to 5.2 ± 0.2 μm in hypertensive mice. We first measured O2- generation by the macula densa and found it was undetectable in control mice. However, O2- generation by the macula densa increased to 21.4 ± 2.5 unit min(-1) in Ang II-induced hypertensive mice. We then measured NO generation and found that NO generation by the macula densa was 138.5 ± 9.3 unit min(-1) in control mice. The NO was undetectable in the macula densa in hypertensive mice infused with Ang II.

CONCLUSIONS

Under physiological conditions, TGF response is mainly controlled by the NO generated in the macula densa; in Ang II induced hypertension, the TGF response is mainly controlled by the O2- generated by the macula densa.

Cohort Profile: Hong Kong Department of Health Elderly Health Service Cohort

The Department of Health Elderly Health Service Cohort in Hong Kong was set up to promote understanding of ageing in a global context, to exploit the role of Hong Kong as a sentinel for populations currently experiencing very rapid economic development, to provide a developed non-Western 'social laboratory' where empirically derived hypotheses can be tested and to leverage the different patterns of common chronic diseases between East and West to generate novel hypotheses about their determinants. The initial cohort enrolled from July 1998 to the end of December 2001 includes 66 820 people aged 65 years or older, forming about 9% of the population of this age. A comprehensive health assessment was made at enrollment and then repeated regularly on an ongoing basis. The health assessment included a comprehensive assessment of lifestyle, social circumstances, physical health and mental health, including an assessment of cognition and depressive symptoms. Health services use and deaths have been obtained by record linkage and confirmed, where necessary, by telephone interview. Currently, the data are not publicly available; we would welcome collaborations and research proposals.

Calreticulin promotes angiogenesis via activating nitric oxide signalling pathway in rheumatoid arthritis

Calreticulin (CRT) is a multi-functional endoplasmic reticulum protein implicated in the pathogenesis of rheumatoid arthritis (RA). The present study was undertaken to determine whether CRT was involved in angiogenesis via the activating nitric oxide (NO) signalling pathway. We explored the profile of CRT expression in RA (including serum, synovial fluid and synovial tissue). In order to investigate the role of CRT on angiogenesis, human umbilical vein endothelial cells (HUVECs) were isolated and cultured in this study for in-vitro experiments. Our results showed a significantly higher concentration of CRT in serum (5·4 ± 2·2 ng/ml) of RA patients compared to that of osteoarthritis (OA, 3·6 ± 0·9 ng/ml, P < 0·05) and healthy controls (HC, 3·7 ± 0·6 ng/ml, P < 0·05); and significantly higher CRT in synovial fluid (5·8 ± 1·2 ng/ml) of RA versus OA (3·7 ± 0·3 ng/ml, P < 0·05). High levels of CRT are expressed in synovial membrane localized predominantly to inflammatory cells and synovial perivascular areas in both the lining and sublining layers of RA synovial tissue (RAST). Increased nitric oxide (NO) production and phosphorylation level of endothelial nitric oxide synthase (eNOS) were measured in HUVECs following CRT stimulation, while the total eNOS expression was not significantly changed. Furthermore, CRT promoted the proliferation, migration and tube formation of HUVECs, which were significantly inhibited by a specific eNOS inhibitor. These findings suggested that CRT may be involved in angiogenesis events in RA through NO signalling pathways, which may provide a potential therapeutic target in the treatment of RA.

Does cross-linked polyethylene decrease the revision rate of total hip arthroplasty compared with conventional polyethylene? A meta-analysis

BACKGROUND

Although cross-linked polyethylene is resistant to wear in comparison to conventional polyethylene, it remains unknown whether it can decrease the wear-related revision rate of total hip arthroplasty.

OBJECTIVES

To determine whether cross-linked polyethylene decreases the wear-related revision rate of total hip arthroplasty compared with conventional polyethylene.

DATA SOURCES

Electronic databases, including PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, were queried from inception to July 6, 2013.

STUDY SELECTION

Randomized controlled trials (RCTs) comparing cross-linked polyethylene with conventional polyethylene were included. In addition, the standard 28-mm femoral head was used, and follow-up was performed for a minimum of 5 years. The primary outcome assessed was wear-related revision. The secondary outcome measures evaluated were the incidence of osteolysis, the linear wear rate, and the linear head penetration.

DATA SYNTHESIS

The Cochrane Collaboration's tool for assessing the risk of bias was used for quality assessment. Data from eligible studies were pooled using a random effects model.

RESULTS

Eight studies involving 735 patients were included in this study. Meta-analysis showed there was no significant difference between cross-linked and conventional polyethylene group in terms of osteolysis or wear-related revision. The pooled mean differences were significantly less for the linear wear rate and linear head penetration for cross-linked polyethylene than for conventional polyethylene.

LIMITATIONS

The studies differed with respect to the cross-linked liner brands, manufacturing processes, and radiological evaluation methods. Moreover, the follow-up periods of the RCTs were not long enough.

CONCLUSIONS

The current limited evidence suggests that cross-linked polyethylene significantly reduced the radiological wear compared with conventional polyethylene at midterm follow-up periods. However, there is no evidence that cross-linked polyethylene had an advantage over conventional polyethylene in terms of reducing osteolysis or wear-related revision. Nevertheless, future long-term RCTs on this topic are needed.

KEY FINDINGS

Cross-linked polyethylene significantly reduced radiological wear but not osteolysis or wear-related revision in comparison to conventional polyethylene at midterm follow-up periods.

LEVEL OF EVIDENCE

Level I, systematic review of level I studies.

Obesity interventions in African American faith-based organizations: a systematic review

African Americans, especially women, have higher obesity rates than the general US population. Because of the importance of faith to many African Americans, faith-based organizations (FBOs) may be effective venues for delivering health messages and promoting adoption of healthy behaviours. This article systematically reviews interventions targeting weight and related behaviours in faith settings. We searched literature published through July 2012 for interventions in FBOs targeting weight loss, diet and/or physical activity (PA) in African Americans. Of 27 relevant articles identified, 12 were randomized controlled trials; seven of these reported a statistically significant change in an outcome. Four of the five quasi-experimental and single-group design studies reported a statistically significant outcome. All 10 pilot studies reported improvement in at least one outcome, but most did not have a comparison group. Overall, 70% of interventions reported success in reducing weight, 60% reported increased fruit and vegetable intake and 38% reported increased PA. These results suggest that interventions in African American FBOs can successfully improve weight and related behaviours. However, not all of the findings about the success of certain approaches were as expected. This review identifies gaps in knowledge and recommends more rigorous studies be conducted to strengthen the comparative methodology and evidence.

Joint detection of ERCC1, TUBB3, and TYMS guidance selection of docetaxel, 5-fluorouracil and cisplatin (DDP) individual chemotherapy in advanced gastric cancer patients

Background

To investigate the guidance selection of docetaxel (D), cisplatin (DDP) (C), and 5-fluorouracil (5-FU) (F) as individual chemotherapy agents via joint detection of ERCC1, TUBB3, and TYMS genes in patients with advanced gastric cancer (AGC).

Method

Clinical data of 120 patients with AGC who enrolled in our hospital between May 2009 and May 2012 were analyzed. These patients were randomly assigned to experimental and control groups. The mRNA expression of ERCC1, TUBB3, and TYMS was measured by DNA chip technology in the experimental group. Different chemotherapies were administered according to the mRNA expression levels of the three genes, while DCF chemotherapy was directly applied to the control group. Correlation between the three genes’ mRNA levels, efficiency rate, the median time to progression (MTP), median survival time (MST) and adverse reactions was evaluated.

Results

As a result, there was a significant correlation between ERCC1 and TUBB3 mRNA expression (P = 0.005), but no obvious correlation between TUBB3 and TYMS or ERCC1 and TYMS. There was also no significant difference in the efficiency rate of chemotherapy (50% versus 55%; P = 0.357) and the MTP (10 months versus 7 months; P = 0.091) between the two groups. However, there was obvious significance in MST (13.7 months versus 11.6 months; P = 0.004). Additionally, the experimental group provided us with a more effective way for controlling adverse reactions to chemotherapy.

Conclusion

Combination regimen of D, C, and F in AGC patients according to their ERCC1, TUBB3, and TYMS mRNA expression level may reduce adverse reactions and improve MST.

Myeloid dendritic cells are primed in allergic asthma for thymic stromal lymphopoietin-mediated induction of Th2 and Th9 responses

BACKGROUND

Type 1 myeloid dendritic cells (mDCs) contribute to inception of allergic asthma (AA) and are regulated by epithelial-derived cytokines.

OBJECTIVES

To evaluate whether mDCs from AA patients are primed for thymic stromal lymphopoietin (TSLP)-driven responses.

METHODS

mDCs from 18 AA patients and 15 controls were purified using immunomagnetic sorting. Cells were pulsed with TSLP or Dermatophagoides pteronyssinus (Der p) allergen, before FACS phenotyping and co-culture with allogeneic CD4+ T cells. Bronchial biopsies from 15 AA patients and four controls were immunostained for CD1c and TSLP receptor (TSLPR).

RESULTS

Allergic asthma patients had a higher proportion of TSLPR+ mDCs, in blood and bronchial mucosa. When compared to mDCs from controls, both TSLP- and Der p-pulsed blood mDCs from AA patients induced increased polarization of CD4+ T cells into Th2 cells (IL-5, IL-13, and GATA3+), while only TSLP-mDCs promoted Th9 cells (IL-9 and PU.1+ /IRF4+). In addition, OX40L was induced upon TSLP stimulation and was required for the induction of Th2, but not Th9, cells. In contrast, development of Th9 cells in this model depended on TGF-β1.

CONCLUSIONS

Our data indicate overlapping but partially distinct effects of TSLP and Der p allergen pathways, showing that DCs are primed in human asthma for TSLP-driven induction of both Th2 and Th9 cells. This novel TSLP/mDC/Th9 axis operates through a distinct, OX40L-independent pathway. These data further highlight the TSLP pathway as a relevant target in human asthma.

A 3-D elasticity theory based model for acoustic radiation from multilayered anisotropic plates

A theoretical model built upon three-dimensional elasticity theory is developed to investigate the acoustic radiation from multilayered anisotropic plates subjected to a harmonic point force excitation. Fourier transform technique and stationary phase method are combined to predict the far-field radiated sound pressure of one-side water immersed plate. Compared to equivalent single-layer plate models, the present model based on elasticity theory can differentiate radiated sound pressure between dry-side and wet-side excited cases, as well as discrepancies induced by different layer sequences for multilayered anisotropic plates. These results highlight the superiority of the present theoretical model especially for handling multilayered anisotropic structures.

Comparison of flucytosine and fluconazole combined with amphotericin B for the treatment of HIV-associated cryptococcal meningitis: a systematic review and meta-analysis

Treatment guidelines recommend combination antifungal therapy with amphotericin B (AmB) as an induction therapy for cryptococcal meningitis. The objective of this study was to compare the survival benefit between 5-FC (flucytosine) and fluconazole as second-line drugs given in combination with AmB. We carried out a systematic review and meta-analysis of prospective controlled studies reporting early combination treatment for human immunodeficiency virus (HIV)-associated cryptococcal meningitis. We searched MEDLINE, EMBASE and the Cochrane Library up to October 2013. Randomised trials and prospective cohort studies were selected. The primary outcome was mortality in the first 14 and 70 days. The secondary outcome was early fungicidal activity (EFA) in the first 2 weeks. Four trials were included in our study. All included studies could be considered to be of fair quality in their methodology. The meta-analysis suggested that mortality was lower in patients who were given AmB and 5-FC at the 2 weeks point (Fig. 2); the overall reduction in mortality with the 5-FC combination group was 44% [risk ratio (RR) 0.56, 95% confidence interval (CI) 0.33-0.95, p = 0.03]. EFA was significantly shorter in patients receiving AmB plus 5-FC [mean difference (MD) -0.10 log10 colony-forming units (CFU) per day, 95 % CI -0.11-0.09, p < 0.00001]. Mortality was no different between the 5-FC and fluconazole groups at the 3 months time point (p = 0.15) (Fig. 4). Adverse events occurred with similar frequency between the two treatment groups. There was no statistically significant difference in the survival rate between AmB in combination with high-dose fluconazole and the current standard of AmB plus 5-FC therapy for HIV-associated cryptococcal meningitis.

Scalable implementation of boson sampling with trapped ions

Boson sampling solves a classically intractable problem by sampling from a probability distribution given by matrix permanents. We propose a scalable implementation of boson sampling using local transverse phonon modes of trapped ions to encode the bosons. The proposed scheme allows deterministic preparation and high-efficiency readout of the bosons in the Fock states and universal mode mixing. With the state-of-the-art trapped ion technology, it is feasible to realize boson sampling with tens of bosons by this scheme, which would outperform the most powerful classical computers and constitute an effective disproof of the famous extended Church-Turing thesis.

Effects of common polymorphisms rs2910164 in miR-146a and rs11614913 in miR-196a2 on susceptibility to colorectal cancer: a systematic review meta-analysis

PURPOSE

Emerging evidence has shown that single nucleotide polymorphisms occurred in microRNAs may contribute to the development of colorectal cancer (CRC). rs2910164 in miR-146a and rs11614913 in miR-196a2 are suggested to be associated with the susceptibility to CRC, but individually published studies revealed inconclusive results. To systematically summarize the possible correlationship between these polymorphisms and CRC risk, we performed this meta-analysis.

METHODS

We retrieved the relevant articles of the associations between these two microRNA polymorphisms and susceptibility to CRC for the period up to July 1, 2013. A total of seven articles were identified with 2,143 cases and 2,457 controls for miR-146a rs2910164, 1,594 cases and 2,252 controls for miR-196a2 rs11614913. Odds ratio and 95 % confidence interval were calculated to investigate the strength of the association.

RESULTS

The pooled analysis showed that miR-146a rs2910164 did not reveal any correlation with CRC susceptibility. However, a decreased risk was observed between miR-196a2 rs11614913 and CRC in all genetic models.

CONCLUSION

Our current meta-analysis demonstrates that miR-196a2 rs11614913 most likely contributes to decreased risk of CRC, whereas miR-146a rs2910164 may not be associated with the susceptibility to CRC.

KL-6 regulated the expression of HGF, collagen and myofibroblast differentiation

OBJECTIVES

KL-6 is a pulmonary epithelial-derived mucin which is secreted mainly by type II alveolar epithelial cells. The level of KL-6 in serum is closely correlated to the clinical activity of various interstitial lung diseases (ILD) and acts as a prognostic factor for ILD patients. Previous studies have showed that KL-6 promoted chemotaxis, proliferation and inhibited the apoptosis of human lung fibroblasts. However, the underlying mechanism remains unknown. In this study, we investigated the function of KL-6 on the expression of hepatocyte growth factor (HGF), transforming growth factor-β1 (TGF-β1), collagen and α-smooth muscle actin(α-SMA) in human embryonic lung fibroblasts cell line MRC-5.

METHODS

Human embryonic lung fibroblasts were cultured in Eagle's minimum essential medium. The cells plated in 6-well plates was cultured in serum-free medium at 37°C in 5% CO2 and challenged with recombinant KL-6 at a final concentration of 0, 10, 20, 40 ng/mL. Five micrograms of total RNA template were transcripted to cDNA by using AMV (Avian Myeloblastosis Virus) reverse transcriptase and random 9 mers as the first-strand primer. Synthesized cDNA was used in PCR experiments. The expression of TGF-β1 and HGF in cell culture supernatants was measured using ELISA kit. Cells incubated with KL-6 for 72h were collected for flow-cytometry analysis. The analysis was done using a Beckman counter device.

RESULTS

It was found that KL-6 up-regulated the expression of collagen type I and III in a dose-dependent manner. However, the addition of KL-6 significantly inhibited the production of HGF. As regard to the biological function, KL-6 induced myofibroblast differentiation confirmed by the elevated expression of a-SMA.

CONCLUSIONS

KL-6 is one of the key molecules involved in epithelial-mesenchymal interactions and might contribute to the fibrosis in ILD.

Identification of epithelial stromal interaction 1 as a novel effector downstream of Krüppel-like factor 8 in breast cancer invasion and metastasis

Krüppel-like factor 8 (KLF8) is a transcriptional factor critical for metastatic progression of breast cancer. Epithelial stromal interaction 1 (EPSTI1), a recently identified stromal fibroblast-induced gene in non-invasive breast cancer cells is highly overexpressed in invasive breast carcinomas. The function and regulation of EPSTI1, however, remain largely unknown. In this paper, we report a novel KLF8 to EPSTI1 signaling pathway in breast cancer. Using various expression analyses, we revealed a high co-overexpression of KLF8 and EPSTI1 in invasive human breast cancer cells and patient tumors. Ectopic overexpression of KLF8 in the non-invasive, MCF-10A cells induced the EPSTI1 expression, whereas KLF8 knockdown from the invasive, MDA-MB-231 cells decreased the EPSTI1 expression. Promoter activation and binding analyses indicated that KLF8 promoted the EPSTI1 expression by directly acting on the EPSTI1 gene promoter. EPSTI1 knockdown dramatically reduced the KLF8-promoted MCF-10A cell invasion and ectopic expression of EPSTI1 in the non-invasive, MCF-7 cells is sufficient to induce the cell invasion. Experiments using nude mice demonstrated that the ectopic EPSTI1 granted the MCF-7 cells capability of both invasive growth in the breasts and metastasis to the lungs. Using co-immunoprecipitation coupled with mass spectrometry, we discovered that EPSTI1 interacts with the valosin containing protein (VCP), resulting in the degradation of IκBα and subsequent activation of NF-κB in the nucleus. These findings suggest a novel KLF8 to EPSTI1 to VCP to NF-κB signaling mechanism potentially critical for breast cancer invasion and metastasis.