Multiple amino acid mutations in viral RNA polymerase may synergistically enhance the transmissibility and/or virulence of the 2009 pandemic influenza (H1N1) virus

Influenza viruses may change their transmissibility and virulence via single or multiple point mutations in the functional regions of their structural proteins. In this study, we compared sequences of all three subunits of viral RNA polymerase, i.e. PA, PB1 and PB2, of the 2009 pandemic influenza A (H1N1) virus isolates from different stages of the pandemic and found that the frequencies of three mutations, including V14I and K716Q in PA and K736G in PB1, showed a similar trend. Interestingly, the death rate of infected patients during the pandemic matched the frequency of the three mutations with a 2-months delay. These findings suggest that the combined mutations may have acted synergistically in enhancing the transmissibility and/or virulence of the 2009 pandemic virus. If definitely proved, this hypothesis could guide the rational design of antiviral therapeutics targeting the RNA polymerase of influenza viruses.

Neotyphodium coenophialum-infected tall fescue and its potential application in the phytoremediation of saline soils

The growth response of endophyte-infected (EI) and endophyte-free (EF) tall fescue to salt stress was investigated under two growing systems (hydroponic and soil in pots). The hydroponic experiment showed that endophyte infection significantly increased tiller and leaf number, which led to an increase in the total biomass of the host grass. Endophyte infection enhanced Na accumulation in the host grass and improved Na transport from the roots to the shoots. With a 15 g l(-1) NaCl treatment, the phytoextraction efficiency of EI tall fescue was 2.34-fold higher than EF plants. When the plants were grown in saline soils, endophyte infection also significantly increased tiller number, shoot height and the total biomass of the host grass. Although EI tall fescue cannot accumulate Na to a level high enough for it to be termed a halophyte, the increased biomass production and stress tolerance suggested that endophyte/plant associations had the potential to be a model for endophyte-assisted phytoextraction in saline soils.

Stimulated mast cells promote maturation of myocardial microvascular endothelial cell neovessels by modulating the angiopoietin-Tie-2 signaling pathway

Angiopoietin (Ang)-1 and Ang-2 interact in angiogenesis to activate the Tie-2 receptor, which may be involved in new vessel maturation and regression. Mast cells (MCs) are also involved in formation of new blood vessels and angiogenesis. The present study was designed to test whether MCs can mediate angiogenesis in myocardial microvascular endothelial cells (MMVECs). Using a rat MMVEC and MC co-culture system, we observed that Ang-1 protein levels were very low even though its mRNA levels were increased by MCs. Interestingly, MCs were able to enhance migration, proliferation, and capillary-like tube formation, which were associated with suppressed Ang-2 protein expression, but not Tie-2 expression levels. These MCs induced effects that could be reversed by either tryptase inhibitor [N-tosyl-L-lysine chloromethyl ketone (TLCK)] or chymase inhibitor (N-tosyl-L-phenylalanyl chloromethyl ketone), with TLCK showing greater effects. In conclusion, our data indicated that MCs can interrupt neovessel maturation via suppression of the Ang-2/Tie-2 signaling pathway.

The prevalence of isolated calf deep vein thrombosis in patients with pulmonary embolism

AIM

Due to discordant results, the risk of isolated calf deep vein thrombosis (DVT) -associated pulmonary embolism (PE) is not well established. This study aimed to detect the prevalence of isolated calf DVT in patients with PE, discussing the importance of isolated calf DVT.

METHODS

We retrospectively reviewed all the inpatients that were both diagnosed PE and DVT between November 2002 and February 2010 in our hospital, analyzed the prevalence of isolated calf DVT and the relevance details.

RESULTS

Among all the 63 patients who were diagnosed both PE and DVT, isolated calf DVT was detected in 23 limbs in 16 patients (16/63=25.4%). Soleal vein was the most frequently involved, with 14 limbs. Ten of the patients had low risk PE, 3 had submassive PE and 3 had massive PE. In the 6 patient who had submassive and massive PE, 4 had bilateral leg calf DVT and all 6 were multiple calf vein involvement.

CONCLUSION

Our results reflected the prevalence of PE at presentation, which was high and included severe cases. Though, as reported, PE during surveillance was the most precisely way to reflect PE in isolated calf DVT, but such a risk of PE at presentation should not just be ignored and its importance still needs to be discussed. Well-designed and adequately powered studies are needed to give strong evidence to recognize the real risk of isolated calf DVT, either at presentation or at surveillance, to distinguish the one with high risk and determine appropriate way to treat it.

Upregulated Hoxc6 expression is associated with poor survival in gastric cancer patients

Human Hox genes (Homeobox) have crucial roles in development and differentiation, regulating numerous processes including apoptosis, receptor signalling, differentiation, motility and angiogenesis. Aberrant expression of Hoxc6 gene has been reported in several tumor tissues and cancer cell lines. The prognostic significance of Hoxc6 in gastric cancer remains largely unknown.This study was aimed to investigate the clinical significance of Hoxc6 in gastric cancer.Total RNA of paired tissue samples (n=25) and a tissue microarray containing 161 paired tissues from patients with gastric cancers at different stages were collected. Quantitative real-time PCR and immunochemistry assay were carried out to investigate the expression of Hoxc6. Hoxc6 mRNA was increased in gastric cancer tissues ( 16 of 25) compared with the adjacent normal mucosa (P<0.05). Immunohistochemical detection showed that expression of Hoxc6 was associated with the depth of tumor invasion (P<0.05). Patients with higher expression levels of Hoxc6 had a shorter overall survival rate (P<0.05).Hoxc6 might contribute to the progression of gastric carcinogenesis and may be a significant predictor of poor survival in patients with gastric cancer after curative operations.

Subinhibitory concentrations of pinocembrin exert anti-Staphylococcus aureus activity by reducing α-toxin expression

AIMS

Natural products have been used as potentially important sources of novel antibacterials in combating pathogenic Staphylococcus aureus isolates, a major problem around the world. In this study, we aimed to investigate the antibacterial effects of pinocembrin (PNCB) against Staph. aureus pneumonia in a murine model and its influence on the production of Staph. aureus α-haemolysin (Hla).

METHODS AND RESULTS

The in vitro activities of PNCB on α-haemolysin production were determined using haemolysis, Western blot and real-time RT-PCR assays. The viability and cytotoxicity assays were performed to evaluate the influence of PNCB on α-toxin-mediated injury of human alveolar epithelial cells. Moreover, through histopathologic analysis, we further determined the in vivo effects of PNCB on Staph. aureus pneumonia in a mouse model. In vitro, PNCB at low concentrations exhibited inhibitory activity against α-haemolysin production and attenuated α-haemolysin-mediated cell injury. Furthermore, the in vivo findings demonstrated that PNCB protected mice from Staph. aureus pneumonia.

CONCLUSIONS

We have provided new evidence of the effects of PNCB, which suggest that PNCB attenuated α-haemolysin-mediated cell injury and protected mice from Staph. aureus pneumonia.

SIGNIFICANCE AND IMPACT OF THE STUDY

The findings indicate that PNCB may be used as a basis for anti-Staphylococcus agent.

A novel experimental method to evaluate motor task control in Parkinson's patients

In this paper, a novel experimental method was developed to study planar arm movement control in tremor dominant Parkinson's (PD) patients. The method utilized a ball-bearing supported fiberglass brace apparatus against gravity to maintain the upper extremity in the horizontal plane. Subjects can perform postural and movement tasks with minimum damping effects. Arm movements were recorded using the MotionMonitor II system concurrently with EMGs of multiple muscles. Testing results in normal subjects with and without the brace support showed that the inertia and damping effects were negligible for oscillatory arm movement at maximum voluntary frequency (MVF). The tremor behaviors in horizontal posture maintenance and reaching movement in three PD subjects were also obtained with this method. The average frequency of postural tremor was 4.34 ± 0.15 Hz in all arm positions tested. However, the tremor magnitudes changed significantly with posture locations. In performing reaching movements, the tremor was inhibited prior to reaching, but resumed after reaching. These results may provide interesting insights into the pathological mechanisms of Parkinsonian tremor, as well as the modular nature of neural control of movements.

Comparative fasting bioavailability and pharmacokinetic properties of 2 formulations of glucosamine hydrochloride in healthy Chinese adult male volunteers

Glucosamine (CAS 66-84-2) hydrochloride is an amino monosaccharide indicated for the treatment of arthrosis, especially osteoarthritis of the knee joint. This study was conducted to assess and compare the pharmacokinetic (PK) properties, bioavailability of a newly developed dispersible tablet formulation (test) of glucosamine hydrochloride with those of an established branded capsule formulation (reference) in healthy Chinese adult male volunteers.This single-dose, randomized, open-label, 2-period crossover study was conducted in 18 healthy Chinese adult male volunteers under fasting condition. Plasma samples were collected at pre-specified times over a 12-h period following administration in each period and analyzed the plasma glucosamine concentrations by Liquid Chromatography coupled with Tandem Mass Spectrometry (LC/MS/MS) method. The mean (SD) PK parameters of Cmax, Tmax, AUC0-12, and AUC0-∞ after administration of the test and reference formulations were, respectively, as follows: Cmax, 907.01 (444.22) vs. 944.40 (429.89) ng/mL, Tmax, 3.03 (0.95) vs. 3.30 (0.99) hours, AUC0-12, 2891.41 (1352.30) vs. 2889.69 (925.48) ng/mL/h, and AUC0-∞, 3029.90 (1321.36) vs. 3091.87 (870.36) ng/mL/h. The mean (SD) t1/2 was 1.10 (0.52) hours for the test formulation and 1.50 (1.17) hours for the reference formulation. On ANOVA, neither period nor sequence effects were observed for any PK properties. The relative bioavailability of the test formulation was 98.3% assessed by AUC0-12. The 90% CIs of glucosamine for the log-transformed ratios of Cmax, AUC0-12, and AUC0-∞ were 78.4-113.9%, 80.8-108.5% and 80.8-105.8%, respectively, meeting the predetermined criteria for bioequivalence of SFDA.

Leptin regulates proliferation and apoptosis of colorectal carcinoma through PI3K/Akt/mTOR signalling pathway

Epidemiological studies have indicated that obesity is associated with colorectal cancer. The obesity hormone leptin is considered as a key mediator for cancer development and progression. The present study aims to investigate regulatory effects of leptin on colorectal carcinoma. The expression of leptin and its receptor Ob-R was examined by immunohistochemistry in 108 Chinese patients with colorectal carcinoma. The results showed that leptin/Ob-R expression was significantly associated with T stage, TNM stage, lymph node metastasis, distant metastasis, differentiation and expression of p-mTOR, p-70S6 kinase, and p-Akt. Furthermore, the effects of leptin on proliferation and apoptosis of HCT-116 colon carcinoma cells were determined. The results showed that leptin could stimulate the proliferation and inhibit the apoptosis of HCT-116 colon cells through the PI3K/Akt/mTOR pathway. Ly294002 (a PI3K inhibitor) and rapamycin (an mTOR inhibitor) could prevent the regulatory effects of leptin on the proliferation and apoptosis of HCT-116 cells via abrogating leptin-mediated PI3K/Akt/mTOR pathway. All these results indicated that leptin could regulate proliferation and apoptosis of colorectal carcinoma through the PI3K/Akt/ mTOR signalling pathway.

Factors Affecting Dental Air-Turbine Handpiece Bearing Failure

Objectives

To investigate the influence of various factors on air-turbine handpiece bearing failure through developing standard protocols for testing the bearing longevity.

Methods

Groups of four air-turbine assemblies (Synea TA-98, W&H, Dentalwerk, Bürmoos, Austria) were subjected repeatedly to a full binary combinatorial set of operating conditions: with and without lubrication, simulated clinical loading, and corrosion protection, all with autoclaving, to the point of failure. A control set was lubricated only. Lubrication (Assistina, W&H), autoclaving (ST-Im30b, Eschmann Bros & Walsh, West Sussex, England), simulated clinical loading (0.56 N at 45° to the turbine axis, after autoclaving), and corrosion protection during autoclaving (magnesium sacrificial anode) were used as required. Free-running speed (Hz) and bearing resistance (μNm) were determined (Darvell-Dyson testing machine) at baseline and after every 10 cycles until turbine failure. Three-way analysis of variance (lubrication × loading × corrosion protection) of log(cycles to failure), with α = 0.05, was used.

Results

All autoclaved turbines had failed by 560 cycles, while the controls failed at 960-1000 cycles. All three main effects were significant: loading (p&lt;10−6), lubrication (p&lt;0.0002), and corrosion protection (p&lt;0.02), as was the interaction lubrication × loading (p&lt;10−6). No other interaction attained significance.

Conclusions

Running under load was the most important factor affecting bearing longevity. While autoclaving clearly has a detrimental effect, lubrication effectively increases longevity. A sacrificial anode may be economically worthwhile to extend life further, but low-load usage patterns, as generally instructed, are confirmed as beneficial.

[Expression of leptin and p-mTOR and their clinicopathological significance in human colon carcinoma]

OBJECTIVE

To investigate the relationship between the expression of leptin, p-mTOR protein and the pathogenesis, development and clinicopathological features in colon carcinoma.

METHODS

The expression of leptin and p-mTOR protein was evaluated by immunohistochemical methods in 40 normal colon mucosas, 40 colon adenomatous polyps and 108 cases of colon carcinomas. The relationship between the staining pattern and clinicopathogical features was examined.

RESULTS

The positive rates of detection of leptin in normal colon mucosa, adenomatous polyps and colon carcinomas were 10% (4/40), 27.5% (11/40), and 71.3% (77/108), respectively; with significant differences among the three groups (P<0.05). The positive rates of p-mTOR protein in the normal colon mucosa, the adenomatous polyps, and the colon carcinomas were 2.5% (1/40), 20% (8/40), and 61.1% (66/108), respectively; with significant differences among the three groups (P<0.05). The expression of leptin and p-mTOR proteins were related to invasive depth, TNM stages, lymph node metastasis, distant metastasis and tumor differentiation (P<0.05), but not to age, sex, or site (P>0.05). In colon carcinoma tissues, leptin expression was positively correlated with p-mTOR expression (P<0.01).

CONCLUSION

Leptin and p-mTOR proteins may play important roles in the occurrence and development of colon carcinoma. The detection of leptin and p-mTOR may be helpful for evaluation of the prognosis of the patient with colon carcinoma.

First Report of Yam mild mosaic virus in Yam in Guangxi Province, China

Yams (Dioscorea spp.) are widely grown in China as vegetables and herbal medicine. However, studies on viral diseases on yams are still limited. As a pilot project of a government initiative for improving yam productivity, a small study was conducted in Guangxi, a southern province of China, on viral disease in yams. Incidence of virus-like disease for the three extensively grown D. alata cultivars, GH2, GH5, and GH6, were 12 to 40%, 12 to 29%, and 11 to 25%, respectively, as found in a field survey with a five-plot sampling method in 2010. A total of 112 leaf samples showing mosaic or mottling or leaves without symptoms were collected from the cvs. GH2, GH5, GH6, and seven additional cultivars (D. alata cvs. GY2, GY23, GY47, GY69, GY62, GY72, and D. batatas cv. Tiegun). To determine if the symptoms were caused by Yam mild mosaic virus (YMMV; genus Potyvirus, family Potyviridae), total RNA was extracted from leaves with a commercial RNA purification kit (TIANGEN, Beijing, China), and reverse-transcription (RT)-PCR was conducted with a YMMV-specific primer pair (4) that amplifies the 3'-terminal portion of the viral genome. A PCR product with the predicted size of 262 bp was obtained from samples of GH5 (number testing positive of total number of leaves = 5 of 12), GH6 (24 of 42), and GY72 (1 of 1), but not from asymptomatic leaves. PCR products from a GH5 sample (YMMV-Nanning) and a GH6 sample (YMMV-Luzhai) were cloned and sequenced using an ABI PRISM 3770 DNA Sequencer. The two PCR products were 97% identical at nucleotide (nt) level and with the highest homology (89% identity) to a YMMV isolate (GenBank Accession No. AJ305466). To further characterize the isolates, degenerate primers (2) were used to amplify viral genome sequence corresponding to the C-terminal region of the nuclear inclusion protein b (NIb) and the N-terminal region of the coat protein (CP). These 781-nt fragments were sequenced and a new primer, YMMV For1 (5'-TTCATGTCGCACAAAGCAGTTAAG-3') corresponding to the NIb region, was designed and used together with primer YMMV UTR 1R to amplify a fragment that covers the complete CP region of YMMV by RT-PCR. These 1,278-nt fragments were sequenced (GenBank Accession Nos. JF357962 and JF357963). CP nucleotide sequences of the YMMV-Nanning and YMMV-Luzhai isolates were 94% similar, while amino acid sequences were 99% similar. BLAST searches revealed a nucleotide identity of 82 to 89% and a similarity of 88 to 97% for amino acids to sequences of YMMV isolates (AF548499 and AF548519 and AAQ12304 and BAA82070, respectively) in GenBank. YMMV is known to be prevalent on D. alata in Africa and the South Pacific, and has recently been identified in the Caribbean (1) and Colombia (3). To our knowledge, this is the first report of the natural occurrence of YMMV in China and it may have implications for yam production and germplasm exchange within China. References: (1) M. Bousalem and S. Dallot. Plant Dis. 84:200, 2000. (2) D. Colinet et al. Phytopathology 84:65, 1994. (3) S. Dallot et al. Plant Dis. 85:803, 2001. (4) R. A. Mumford and S. E. Seal. J. Virol. Methods 69:73, 1997.