Lactobacillus rhamnosus strain JB-1 reverses restraint stress-induced gut dysmotility

BACKGROUND

Environmental stress affects the gut with dysmotility being a common consequence. Although a variety of microbes or molecules may prevent the dysmotility, none reverse the dysmotility.

METHODS

We have used a 1 hour restraint stress mouse model to test for treatment effects of the neuroactive microbe, L. rhamnosus JB-1^™ . Motility of fluid-filled ex vivo gut segments in a perfusion organ bath was recorded by video and migrating motor complexes measured using spatiotemporal maps of diameter changes.

KEY RESULTS

Stress reduced jejunal and increased colonic propagating contractile cluster velocities and frequencies, while increasing contraction amplitudes for both. Luminal application of 10E8 cfu/mL JB-1 restored motor complex variables to unstressed levels within minutes of application. L. salivarius or Na.acetate had no treatment effects, while Na.butyrate partially reversed stress effects on colonic frequency and amplitude. Na.propionate reversed the stress effects for jejunum and colon except on jejunal amplitude.

CONCLUSIONS & INFERENCES

Our findings demonstrate, for the first time, a potential for certain beneficial microbes as treatment of stress-induced intestinal dysmotility and that the mechanism for restoration of function occurs within the intestine via a rapid drug-like action on the enteric nervous system.

A meta-analysis of serum p16 gene promoter methylation for diagnosis of nonsmall cell lung cancer

OBJECTIVES

To evaluate the diagnostic value of serum p16 gene promoter methylation for diagnosis of nonsmall cell lung cancer (NSCLC).

MATERIALS AND METHODS

By searching the databases of PubMed and CNKI, we included all the published articles related serum p16 gene promoter methylation and nonsmall lung cancer. The true positive, false positive, false negative, and true negative data for each included publication were extracted by the reviewers. The diagnostic sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and area under the receiver operating characteristic (ROC) were pooled by MetaDiSc1.4 software.

RESULTS

Finally, 13 manuscripts with 1440 subjects were involving in this diagnostic meta-analysis. The pooled sensitivity and specificity were 0.25 (95% confidence interval [CI]: 0.18-0.32) and 0.95 (95% CI: 0.93-0.97), respectively, with randomized effect model. The pooled positive likelihood ratio and negative likelihood ratio were 5.08 (95% CI: 3.00-8.62) and 0.69 (95% CI: 0.62-0.77) with fixed effect model and randomized effect model, respectively. The diagnostic ROC curve for the included 13 publications was pooled by statistical software MetaDiSc14.0 according to the Bayes theorem. The pooled area under the ROC was 0.72 with its standard error of 0.10.

CONCLUSION

According to the published articles, high specificity and low sensitivity were found in this meta-analysis for the p16 gene promoter methylation in the diagnosis of NSCLC.

[Economic evaluation on different two-dose-vaccination-strategies related to Measles, Mumps and Rubella Combined Attenuated Live Vaccine]

OBJECTIVE

To evaluate the economic effect of Measles, Mumps and Rubella Combined Attenuated Live Vaccine (MMR) under different two-dose vaccination programs.

METHODS

A hypothetical birth cohort of 750 000 infants over their lifetime, was followed up from birth through death in Zhejiang province. The current MMR vaccination strategie would include three different ones: 1) Childlern were vaccinated with Measles-Rubella Combined Attenuated Live Vaccine and MMR, respectively at the age of 8 months and 18 months. 2) Children receive MMR at 8 months and 18 months, 3) Strategy 1 plus an additional vaccination of MMR at 4 years of age. Incremental cost-effectiveness ratio (ICER), incremental cost-benefit ratio (ICBR) and incremental net benefit (INB) were applied to calculate the health economic difference for Strategy 2 and Strategy 3 as compared to Strategy 1. Univariate sensitivity analysis was used to assess the robustness of results with main parameters, including the rate of immunization coverage, effectiveness of the vaccines, incidence and burdens of the related diseases, cost of vaccines and the vaccination program itself.

RESULTS

ICER, ICBR and INB for Strategy 2 and Strategy 3 appeared as 2 012.51∶1 RMB Yuan per case and 4 238.72∶1 RMB Yuan per case, 1∶3.14 and 1∶1.58, 21 277 800 RMB Yuan and 9 276 500 RMB Yuan, respectively. Only slight changes (<20%) were found under the univariate sensitivity analysis, with varied values on main parameters.

CONCLUSION

Based on the current national immunization program, infants vaccinated with MMR at 8 months of age, generated more health economic effects than the Strategy 3.

Non-immunosuppressive FTY720-derivative OSU-2S mediates reactive oxygen species-mediated cytotoxicity in canine B-cell lymphoma

OSU-2S is a FTY720 (Fingolimod) derivative that lacks immunosuppressive properties but exhibits strong anti-tumour activity in several haematological and solid tumour models. We have recently shown OSU-2S to mediate potent cytotoxicity in human mantle cell lymphoma cell lines and primary cells. We report here the pre-clinical activity of OSU-2S in spontaneous B-cell lymphoma of dogs which shares many characteristics of human lymphoma. OSU-2S mediated apoptosis in canine B-cell lines and primary B-cell lymphoma cells obtained from spontaneous lymphoma bearing dogs. OSU-2S induced reactive oxygen species (ROS) in canine lymphoma cells and inhibition of ROS partially rescued OSU-2S-mediated cell death. These studies provide a rational basis for the use of spontaneous lymphoma in pet dogs as a preclinical large animal model for the development of OSU-2S as small molecule for treating people and dogs with lymphoma.

Anti-CII antibody as a novel indicator to assess disease activity in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that affects a variety of organ systems. Anti-dsDNA Abs and complement factors have been used as indicators of lupus activity for more than 50 years. A novel indicator of activation in SLE is reported in this paper. Anti-collagen type II (CII) Ab was obviously elevated in patients with SLE compared to those patients with ankylosing spondylitis (AS) and healthy controls (HCs). Anti-CII-Ab-positive patients with SLE showed significantly higher levels of serum IgG and higher titers of ANA but lower levels of C3 and C4 than controls. A positive correlation was demonstrated between anti-CII Ab and serum IgG in SLE patients (r = 0.50, p < 0.0001). The negative correlations of anti-CII Ab with C3 and C4 were observed in SLE patients (r = -0.36, p = 0.0013; r = -0.37, p = 0.0006, respectively). The reduced anti-CII Ab level was accompanied by decreased level of serum IgG and increased levels of C3 and C4 after regular treatment. Therefore, anti-CII Ab could be a novel indicator for monitoring activity of SLE.

Effect of grass pollen immunotherapy on clinical and local immune response to nasal allergen challenge

Rationale

Nasal allergen provocations may be useful in investigating the pathophysiology of allergic rhinitis and effects of treatments.

Objective

To use grass pollen nasal allergen challenge (NAC) to investigate the effects of allergen immunotherapy in a cross‐sectional study.

Methods

We studied nasal and cutaneous responses in untreated subjects with seasonal grass‐pollen allergic rhinitis (n = 14) compared with immunotherapy‐treated allergics (n = 14), plus a nonatopic control group (n = 14). Volunteers underwent a standardized NAC with 2000 biological units of timothy grass allergen (equivalent to 1.3 μg major allergen, Phl p5). Nasal fluid was collected and analysed by ImmunoCAP and multiplex assays. Clinical response was assessed by symptom scores and peak nasal inspiratory flow (PNIF). Cutaneous response was measured by intradermal allergen injection. Retrospective seasonal symptom questionnaires were also completed.

Results

Immunotherapy‐treated patients had lower symptom scores (P = 0.04) and higher PNIF (P = 0.02) after challenge than untreated allergics. They had reduced early (P = 0.0007) and late (P < 0.0001) skin responses, and lower retrospective seasonal symptom scores (P < 0.0001). Compared to untreated allergics, immunotherapy‐treated patients had reduced nasal fluid concentrations of IL‐4, IL‐9 and eotaxin (all P < 0.05, 8 h level and/or area under the curve comparison), and trends for reduced IL‐13 (P = 0.07, area under the curve) and early‐phase tryptase levels (P = 0.06).

Conclusions

Nasal allergen challenge is sensitive in the detection of clinical and biological effects of allergen immunotherapy and may be a useful surrogate marker of treatment efficacy in future studies.

Tumor antigen ROR1 targeted drug delivery mediated selective leukemic but not normal B-cell cytotoxicity in chronic lymphocytic leukemia

Selective cytotoxicity to cancer cells without compromising their normal counterparts pose a huge challenge for traditional drug design. Here we developed a tumor antigen-targeted delivery of immunonanoparticle carrying a novel non-immunosuppressive FTY720 derivative OSU-2S with potent cytotoxicity against leukemic B cells. OSU-2S induces activation of protein phosphatase 2A (PP2A), phosphorylation and nuclear translocation of SHP1(S591) and deregulation of multiple cellular processes in chronic lymphocytic leukemia (CLL) resulting in potent cytotoxicity. To preclude OSU-2S-mediated effects on these ubiquitous phosphatases in unintended cells and avoid potential adverse effects, we developed an OSU-2S-targeted delivery of immunonanoparticles (2A2-OSU-2S-ILP), that mediated selective cytotoxicity of CLL but not normal B cells through targeting receptor tyrosine kinase ROR1 expressed in leukemic but not normal B cells. Developing a novel spontaneous CLL mouse model expressing human ROR1 (hROR1) in all leukemic B cells, we demonstrate the therapeutic benefit of enhanced survival with 2A2-OSU-2S-ILP in vivo. The newly developed non-immunosuppressive OSU-2S, its delivery using human CLL directed immunonanoparticles and the novel transgenic (Tg) mouse model of CLL that expresses hROR1 exclusively in leukemic B cell surface are highly innovative and can be applied to CLL and other ROR1+ malignancies including mantle cell lymphoma and acute lymphoblastic leukemia.

Early third trimester maternal response to glucose challenge and pregnancy outcome in Chinese women-relationship between upper distribution level and recommended diagnostic criteria

BACKGROUND/OBJECTIVES

The objective of this study was to examine the relationship between upper distribution levels of glucose values in the 75-g oral glucose tolerance test (OGTT) and recommended diagnostic criteria for gestational diabetes mellitus (GDM) and adverse pregnancy outcomes.

SUBJECTS/METHODS

The distribution of the OGTT 2-h values of 13,501 pregnant women, which were below the World Health Organization (WHO) threshold for overt diabetes mellitus (DM), and managed in one teaching hospital in China, was reviewed and related to maternal characteristics and pregnancy outcomes.

RESULTS

For the entire group, the 90th and 95th percentile values of the OGTT 2-h glucose level, respectively, were close to the diagnostic cutoff values of the WHO and International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. For adverse maternal outcomes, glucose level above the 90th percentile value was associated with increased hypertensive disorders, whereas no difference was seen with cutoff using the 95th percentile value. For perinatal outcomes, the 90th percentile was associated with increased neonatal intensive care unit admission and hypoglycemia, whereas the 95th percentile showed in addition association with phototherapy for jaundice and 5th-minute Apgar score <7. Although no differences in the incidence of adverse pregnancy outcomes were found using the different cutoffs, the >95th percentile cutoff value would have missed out 33.3-56.7% of the cases of adverse outcomes that would otherwise have been attributed to GDM.

CONCLUSIONS

Further studies are warranted to clarify which diagnostic criterion is most appropriate universally to identify adverse pregnancy outcomes attributed to GDM, and which could be mitigated with treatment specific for GDM.

Nom1 mediates pancreas development by regulating ribosome biogenesis in zebrafish

Ribosome biogenesis is an important biological process for proper cellular function and development. Defects leading to improper ribosome biogenesis can cause diseases such as Diamond-Blackfan anemia and Shwachman-Bodian-Diamond syndrome. Nucleolar proteins are a large family of proteins and are involved in many cellular processes, including the regulation of ribosome biogenesis. Through a forward genetic screen and positional cloning, we identified and characterized a zebrafish line carrying mutation in nucleolar protein with MIF4G domain 1 (nom1), which encodes a conserved nulceolar protein with a role in pre-rRNA processing. Zebrafish nom1 mutants exhibit major defects in endoderm development, especially in exocrine pancreas. Further studies revealed that impaired proliferation of ptf1a-expressing pancreatic progenitor cells mainly contributed to the phenotype. RNA-seq and molecular analysis showed that ribosome biogenesis and pre-mRNA splicing were both affected in the mutant embryos. Several defects of ribosome assembly have been shown to have a p53-dependent mechanism. In the nom1 mutant, loss of p53 did not rescue the pancreatic defect, suggesting a p53-independent role. Further studies indicate that protein phosphatase 1 alpha, an interacting protein to Nom1, could partially rescue the pancreatic defect in nom1 morphants if a human nucleolar localization signal sequence was artificially added. This suggests that targeting Pp1α into the nucleolus by Nom1 is important for pancreatic proliferation. Altogether, our studies revealed a new mechanism involving Nom1 in controlling vertebrate exocrine pancreas formation.

Qualitative analysis and enantiospecific determination of angular-type pyranocoumarins in Peucedani Radix using achiral and chiral liquid chromatography coupled with tandem mass spectrometry

Angular-type pyranocoumarins (APs), the derivatives of khellactone, are widely documented as the main active constituents in Peucedani Radix (Chinese name: Qian-hu). Owing to the natural occurrence of chiral centers, enantiomers of APs are extensively distributed in the original plant, and enantioselective performances have been definitely demonstrated for these enantiomers. In current study, the chemical characterization of the major and minor APs in Peucedani Radix was performed using ultra high performance liquid chromatography coupled with diode array detector and hybrid ion trap-orbitrap mass spectrometry. On the other hand, a heart-cut two-dimensional achiral-chiral liquid chromatography combining triple quadropole-linear ion trap mass spectrometry system (2D LC-MS/MS) was developed for simultaneous enantiospecific quantification of eighteen coumarins, including seven pairs of enantiomers. Eleven APs (1-11) were recruited to propose UV absorption characteristics and electrospray ionization fragmentation patterns of APs. A total of 42 components were categorized into APs based on their UV spectral properties and identified according to the proposed mass fragmentation pathways, while two linear-type furanocoumarins (12-13) were unambiguously assigned by further purification. A Capcell core RP-C18 column was employed in the primary LC dimension to achieve efficient racemic separation for the main chemical constituents (1-9 and 12-13) in Peucedani Radix, while a Chiralpak AD-RH column was utilized in the secondary dimension to contribute enantioselective separation for seven enantiomerically enriched components (1, 3 and 5-9). Collectively, the results provided the chemical evidences for revealing the material basis of the therapeutic effects of Peucedani Radix, and the developed 2D LC-MS/MS system in the present study is expected to be an ideal tool for the quality control of Peucedani Radix as well as a reliable technique for complex matrices containing both achiral and chiral components.

Observation of self-similarity in the magnetic fields generated by the ablative nonlinear Rayleigh-Taylor instability

Magnetic fields generated by the nonlinear Rayleigh-Taylor growth of laser-seeded three-dimensional broadband perturbations were measured in laser-accelerated planar targets using ultrafast proton radiography. The experimental data show self-similar behavior in the growing cellular magnetic field structures. These observations are consistent with a bubble competition and merger model that predicts the time evolution of the number and size of the bubbles, linking the cellular magnetic field structures with the Rayleigh-Taylor bubble and spike growth.

A novel anti-tumor inhibitor identified by virtual screen with PLK1 structure and zebrafish assay

Polo-like kinase 1 (PLK1), one of the key regulators of mitosis, is a target for cancer therapy due to its abnormally high activity in several tumors. Plk1 is highly conserved and shares a nearly identical 3-D structure between zebrafish and humans. The initial 10 mitoses of zebrafish embryonic cleavages occur every∼30 minutes, and therefore provide a rapid assay to evaluate mitosis inhibitors including those targeting Plk1. To increase efficiency and specificity, we first performed a computational virtual screen of∼60000 compounds against the human Plk1 3-D structure docked to both its kinase and Polo box domain. 370 candidates with the top free-energy scores were subjected to zebrafish assay and 3 were shown to inhibit cell division. Compared to general screen for compounds inhibiting zebrafish embryonic cleavage, computation increased the efficiency by 11 folds. One of the 3 compounds, named I2, was further demonstrated to effectively inhibit multiple tumor cell proliferation in vitro and PC3 prostate cancer growth in Xenograft mouse model in vivo. Furthermore, I2 inhibited Plk1 enzyme activity in a dose dependent manner. The IC50 values of I2 in these assays are compatible to those of ON-01910, a Plk1 inhibitor currently in Phase III clinic trials. Our studies demonstrate that zebrafish assays coupled with computational screening significantly improves the efficiency of identifying specific regulators of biological targets. The PLK1 inhibitor I2, and its analogs, may have potential in cancer therapeutics.

Comparison of FIB-4 and APRI in Chinese HBV-infected patients with persistently normal ALT and mildly elevated ALT

Significant liver disease has been reported in chronic hepatitis B patients with normal alanine aminotransferase (ALT). Liver biopsy (LB) is the current gold standard for assessing hepatic inflammation and fibrosis in patients with chronic HBV. However, associated risks have led to the development of noninvasive models. Their utility in patients with normal ALT is unknown. FIB-4 and aspartate aminotransferase (AST)-to-platelet ratio index (APRI) were calculated for patients with chronic HBV infection undergoing biopsy. The performance of each model and AUROC for predicting significant fibrosis (Scheuer's score ≥ S2) were determined for the entire cohort and stratified by elevated (≥50 U/L) and normal ALT. Two-hundred and thirty-one liver biopsies were included. The number of patient with normal ALT was 140, and 22.1% had significant fibrosis. The AUROC curve for patients with normal ALT was 0.81 for FIB-4 and 0.80 for APRI, compared with 0.71 for FIB-4 and 0.72 for APRI for those with mildly elevated ALT level. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FIB-4 were 0.63, 0.88, 0.61 and 0.93, for patients with normal ALT; the values for APRI were 0.40, 0.88, 0.33 and 0.93. Both FIB-4 and APRI are useful for identification of those without significant fibrosis. However, because they have poor PPV, LB will continue to be used for assessment of HBV-infected patients with normal ALT and mildly elevated ALT.

Generating energetic electrons through staged acceleration in the two-plasmon-decay instability in inertial confinement fusion

A new hot-electron generation mechanism in two-plasmon-decay instabilities is described based on a series of 2D, long-term (~10 ps) particle-in-cell and fluid simulations under parameters relevant to inertial confinement fusion. The simulations show that significant laser absorption and hot-electron generation occur in the nonlinear stage. The hot electrons are stage accelerated from the low-density region to the high-density region. New modes with small phase velocities develop in the low-density region in the nonlinear stage and form the first stage for electron acceleration. Electron-ion collisions are shown to significantly reduce the efficiency of this acceleration mechanism.

Trichosanthin-stimulated dendritic cells induce a type 2 helper T lymphocyte response through the OX40 ligand

BACKGROUND

Trichosanthin (TCS) induces a type 2 helper T lymphocyte (T(H)2) immune response that leads to the production of TCS-specific immunoglobulin (Ig) E and a subsequent allergic reaction in vivo. However, events immediately following treatment with TCS are poorly understood.

OBJECTIVE

We aimed to investigate whether dendritic cells (DCs) are the initial mediators of T(H)2 cell polarization induced by TCS and to investigate potential causative mechanisms

METHODS

DCs were cultured from purified human peripheral monocytes in the presence of granulocyte-macrophage colony-stimulating factor and interleukin (IL) 4. Flow cytometry was used to analyze cell surface antigen, intracellular cytokines, DC endocytic capacity, and apoptosis. The transcriptional profile for 120 genes in DCs was detected using oligonucleotide microarray analysis.

RESULTS

TCS exerted a cytotoxic effect on DCs in a concentration-dependent manner. Although TCS alone did not induce full maturation of DC, it did so in the presence of tumor necrosis factor alpha and IL-1beta in vitro. TCS-stimulated DCs induced a decreased ratio of T(H)1/T(H)2 cells derived from naïve T cells and showed selective expression of OX40 ligand (OX40L) at both mRNA and protein levels. This induction was partially blocked by anti-OX40L antibody.

CONCLUSION

Our results imply that TCS-stimulated DCs polarize the development of T(H)2 cells partially by means of the OX40L signal. Modulation of these DC will favor the alleviation of TCS-induced allergy.

Predicted probability of meniscus tears: comparing history and physical examination with MRI

BACKGROUND

The indication for surgical treatment of a meniscal lesion should not only rely on magnetic resonance imaging (MRI) findings, but also on a detailed history and a thorough clinical examination. However, various intra-articular lesions may often produce similar symptoms. So, what kinds of symptoms are more associated with a meniscal tear? Is MRI worth doing?

OBJECTIVE

The aims of this study were to identify sensitive and specific clinical tests and elements of patients' history with a high predictive value, and to assess the combined diagnostic accuracy of sensitive and specific clinical tests and elements of patients' history with MRI.

METHODS

Data from 281 consecutive knee arthroscopies to investigate and treat suspected internal knee pathologies were retrospectively collected between March 2009 and April 2010. The study group consisted of 262 knees. Statistically significant factors in the clinical diagnosis of meniscal tears were screened by a chi-square test. Logistic regression analysis was used to determine which factors associated with meniscal tears found during arthroscopy. The diagnostic values of MRI and the sensitive and specific clinical tests and elements of patients' history with high predictive value for meniscal tears were calculated.

RESULTS

The overall diagnostic value of MRI for meniscal tears was: accuracy, 88.8%; sensitivity, 95.7%; specificity, 75.8%; positive predictive value (PPV), 88.2%; and negative predictive value (NPV), 90.4%. Giving way, locking and McMurray's test were independent diagnostic factors with a predicted correct percentage of 80.0% (p <0.05) for the diagnosis of meniscal tears found during arthroscopy. Locking, McMurray's test and MRI increased the predicted correct percentage of meniscal tears found during arthroscopy to 91.6% (p <0.05). For the diagnosis of meniscal tears found during arthroscopy, giving way, locking and McMurray's test had the following values for accuracy (49.2, 60.9, 76), sensitivity (43.5, 55.2, 75.8), specificity (84, 96, 76.9), PPV (94.4, 98.8, 95.1) and NPV (19.4, 25.8, 35.1). Combining MRI, the diagnostic values of giving way, locking, and McMurray's test were: accuracy, 88.3,89.9,89.4; sensitivity, 95.7,97.4,97.4; specificity, 74.2,75.8,74.2; PPV, 87.5,88.4,87.7; and NPV, 90.2,94,93.9.

CONCLUSIONS

Giving way, locking and McMurray's test are independent clinical diagnostic factors for the diagnosis of meniscal tears. MRI has higher accuracy, sensitivity and NPV for the diagnosis of meniscal tears than giving way, locking and McMurray's test. The combination of giving way, locking, McMurray's test and MRI for confirmation is typical for a meniscal lesion diagnosis. Based on these findings, MRI should be used in a standard manner to detect meniscal tears found during arthroscopy.

Stereoselective metabolism of (±)-praeruptorin A, a calcium channel blocker from Peucedani Radix, in pooled liver microsomes of rats and humans

(±)-Praeruptorin A (PA) is the major component of Peucedani Radix. The present study investigated stereoselectivity in PA metabolism in liver microsomes of rats (RLMs) and humans (HLMs), for the first time. PA was enantioseparated by semi-preparative chiral HPLC. Metabolic profiles of the dextrorotatory (dPA) and the levorotatory (lPA) forms in HLMs and RLMs were determined using LC-MS/MS. (-)-cis-Khellactone (D1) prepared from basic hydrolysis of dPA, and (3'R, 4'R)-4'-angeloyl-khellactone (L8) and (3'R, 4'R)-3'-angeloyl-khellactone (L9) isolated from a scale-up incubation of lPA with rat plasma were unambiguously identified by LC-MS/MS and NMR analysis. Other metabolites were tentatively identified using LC-MS/MS. In the absence of NADPH-regenerating system, dPA remained intact, however, lPA yielded L8 and L9 via a carboxylesterase(s)-mediated process. In the presence of NADPH-regenerating system, lPA produced 9 (L1-9) metabolites in both species, while dPA generated 12 (D1-12) and 6 (D1-3, 6, 9 and 10) metabolites in RLMs and HLMs, respectively. Hydrolysis, oxidation and acyl migration were demonstrated to be the predominant pathways for both enantiomers. Both enantiomers were eliminated faster in RLMs than in HLMs, while lPA showed greater species difference. PA enantiomers exhibited stereoselective metabolism in RLMs and HLMs, implying chiral discrimination in their actions.

Ratio-contrast imaging of dual-energy absorption for element mapping with a scanning transmission X-ray microscope

The detection of chemical mapping with a spatial resolution of 30 nm has been achieved with a scanning transmission X-ray microscope at the Shanghai Synchrotron Radiation Facility. For each specimen, two absorption images were scanned separately with energies E(1) and E(2): E(1) was focused on the absorption edge of the chosen element and E(2) was focused below the edge. A K-edge division method is proposed and applied to obtain the element mapping. Compared with the frequently used K-edge subtraction method, this ratio-contrast method is shown to be more accurate and sensitive in identifying the elements of interest, where the definition of the contrast threshold is simple and clear in physics. Several examples are presented to illustrate the effectiveness of the method.

A novel endophytic Huperzine A-producing fungus, Shiraia sp. Slf14, isolated from Huperzia serrata

AIMS

To characterize and identify a novel Huperzine A (HupA)-producing fungal strain Slf14 isolated from Huperzia serrata (Thunb. ex Murray) Trev. in China.

METHODS AND RESULTS

The isolation, identification and characterization of a novel endophytic fungus producing HupA specifically and consistently from the leaves of H. serrata were investigated. The fungus was identified as Shiraia sp. Slf14 by molecular and morphological methods. The HupA produced by this endophytic fungus was shown to be identical to authentic HupA analysed by thin layer chromatographic, High-performance liquid chromatography (HPLC), LC-MS, (1) H NMR and acetylcholinesterase (AChE) inhibition activity in vitro. The amount of HupA produced by Shiraia sp. Slf14 was quantified to be 327.8 μg l(-1) by HPLC, which was far higher than that of the reported endophytic fungi, Acremonium sp., Blastomyces sp. and Botrytis sp.

CONCLUSIONS

The production of HupA by endophyte Shiraia sp. Slf14 is an enigmatic observation. It would be interesting to further study the HupA production and regulation by the cultured endophyte in H. serrata and in axenic cultures.

SIGNIFICANCE AND IMPACT OF THE STUDY

Although the current accumulation of HupA by the endophyte is not very high, it could provide a promising alterative approach for large-scale production of HupA. However, further strain improvement and the fermentation process optimization are required to result in the consistent and dependable production.

The glycoprotein Ibalpha-von Willebrand factor interaction induces platelet apoptosis

BACKGROUND

The interaction of glycoprotein (GP) Ibalpha with von Willebrand factor (VWF) initiates platelet adhesion, and simultaneously triggers intracellular signaling cascades leading to platelet aggregation and thrombus formation. Some of the signaling events are similar to those occurring during apoptosis, however, it is still unclear whether platelet apoptosis is induced by the GPIbalpha-VWF interaction.

OBJECTIVES

To investigate whether the GPIbalpha-VWF interaction induces platelet apoptosis and the role of 14-3-3zeta in apoptotic signaling.

METHODS

Apoptotic events were assessed in platelets or Chinese hamster ovary (CHO) cells expressing wild-type (1b9) or mutant GPIb-IX interacting with VWF by flow cytometry or western blotting.

RESULTS

Ristocetin-induced GPIbalpha-VWF interaction elicited apoptotic events in platelets, including phosphatidylserine exposure, elevations of Bax and Bak, gelsolin cleavage, and depolarization of mitochondrial inner transmembrane potential. Apoptotic events were also elicited in platelets exposed to pathologic shear stresses in the presence of VWF; however, the shear-induced apoptosis was eliminated by the anti-GPIbalpha antibody AK2. Furthermore, apoptotic events occurred in 1b9 cells stimulated with VWF and ristocetin, but were significantly diminished in two CHO cell lines expressing mutant GPIb-IX with GPIbalpha truncated at residue 551 or a serine-to-alanine mutation at the 14-3-3zeta-binding site in GPIbalpha.

CONCLUSIONS

This study demonstrates that the GPIbalpha-VWF interaction induces apoptotic events in platelets, and that the association of 14-3-3zeta with the cytoplasmic domain of GPIbalpha is essential for apoptotic signaling. This finding may suggest a novel mechanism for platelet clearance or some thrombocytopenic diseases.

Growth and saturation of convective modes of the two-plasmon decay instability in inertial confinement fusion

Particle-in-cell (PIC) and fluid simulations of two-plasmon decay (TPD) instability under conditions relevant to inertial confinement fusion show the importance of convective modes. Growing at the lower density region, the convective modes can cause pump depletion and are energetically dominant in the nonlinear stage. The PIC simulations show that TPD saturates due to ion density fluctuations, which can turn off TPD by raising the instability threshold through mode coupling.

Laser channeling in millimeter-scale underdense plasmas of fast-ignition targets

Two dimensional particle-in-cell simulations show that laser channeling in millimeter-scale underdense plasmas is a highly nonlinear and dynamic process involving longitudinal plasma buildup, laser hosing, channel bifurcation and self-correction, and electron heating to relativistic temperatures. The channeling speed is much less than the linear group velocity of the laser. The simulations find that low-intensity channeling pulses are preferred to minimize the required laser energy but with an estimated lower bound on the intensity of I approximately 5x10(18) W/cm(2) if the channel is to be established within 100 ps. The channel is also shown to significantly increase the transmission of an ignition pulse.

Reticulon proteins: emerging players in neurodegenerative diseases

Reticulons (RTNs) are a group of integral membrane proteins that have a uniquely conserved C-terminal domain named RHD. In mammalian genomes, transcripts are produced from four genes, rtn1 to rtn4, under the regulation of tissue or cell-type-specific expression. The presence of alternative promoters for gene expression and multiple cryptic splicing sites have resulted in large numbers of genes/proteins that are classified among the reticulon family. Although this family exists in almost all eukaryotes, only the rtn4 gene product, Nogo (RTN4), has gained relatively more in-depth attention. Despite predominant localization in the endoplasmic reticulum, Nogo on the cell surface appears to play a critical role as an inhibitory molecule for axonal growth and regeneration in humans and rodents. Recently, studies have expanded the biological functions of RTNs to other facets including modulating the enzymatic activity of beta-secretase in Alzheimer's disease. In this review, we summarize the accumulated findings concerning the structural and functional aspects of RTNs and speculate on their linkage to the pathogenesis of neurodegenerative diseases.

Stable gene silencing of cyclin B1 in tumor cells increases susceptibility to taxol and leads to growth arrest in vivo

Cyclin B1 is the regulatory subunit of cyclin-dependent kinase 1 (Cdk1) and is critical for the initiation of mitosis. Accumulating data indicate that the deregulation of cyclin B1 is tightly linked to neoplastic transformation. To study the phenotype and the potential preclinical relevance, we generated HeLa cell lines stably transfected with the plasmids encompassing short hairpin RNA (shRNA) targeting cyclin B1. We demonstrate that the reduction of cyclin B1 caused inhibition of proliferation by arresting cells in G2 phase and by inducing apoptosis. Cells, entering mitosis, were impaired in chromosome condensation and alignment. Importantly, HeLa cells with reduced cyclin B1 were more susceptible to the treatment of small interfering RNA targeting Polo-like kinase 1 (Plk1) and to the administration of the chemotherapeutic agent taxol. Finally, HeLa cells with reduced cyclin B1 showed inhibited tumor growth in nude mice compared to that of control cells. In summary, our data indicate that cyclin B1 is an essential molecule for tumor cell survival and aggressive proliferation, suggesting that the downregulation of cyclin B1, especially in combination with other molecular targets, might become an interesting strategy for antitumor intervention.

Isolation and characterization of sulphur-oxidizing Thiomonas sp. and its potential application in biological deodorization

AIMS

To isolate and characterize a sulphur-oxidizing bacterial strain from activated sludge and to evaluate its potential application in biological deodorization.

METHODS AND RESULTS

A dominant sulphur-oxidizing bacterial strain, designated as strain SS, was isolated from an enrichment culture using thiosulphate as a sole energy source and CO2 as a sole carbon source. The cells of this organism were aerobic, rod-shaped, Gram-negative and motile. Strain SS could grow autotrophically, heterotrophically as well as mixotrophically. Autotrophic growth was observed at pH values ranging from 2.3 to 9.0. Phylogenetic analyses revealed that strain SS belonged to Group 1 of the genus Thiomonas, closely related to Thiomonas perometabolis and Thiomonas intermedia. The thiosulphate oxidation rates of strain SS at different pH values were evaluated in terms of oxygen uptake using a Micro-Oxymax respirometer. The results showed that the maximum oxidation rate of 5.65 mg l(-1) h(-1) occurred at 56 h of growth and pH 6.0. Continuous H2S removal study demonstrated that strain SS could remove more than 99% of H2S when the inlet concentration was below 58.6 ppm. Further increase of the inlet concentration to 118 ppm gave rise to a decline in the removal efficiency to ca 90%.

CONCLUSIONS

The strong acidification of the culture medium during the later period could result in the deterioration of the growth activity and the metabolism activity of strain SS. In practical application, the problems caused by the end-product inhibition and the acidification can be alleviated by periodical replacement of culture medium with fresh medium. Given the physiological flexibility and the ability to remove H2S rapidly and efficiently, strain SS could be a good 'deodorizing' candidate.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first time that Thiomonas species has been reported for biological deodorization application.

Use of activated carbon as a support medium for H2S biofiltration and effect of bacterial immobilization on available pore surface

The use of support media for the immobilization of microorganisms is widely known to provide a surface for microbial growth and a shelter that protects the microorganisms from inhibitory compounds. In this study, activated carbon is used as a support medium for the immobilization of microorganisms enriched from municipal sewage activated sludge to remove gas-phase hydrogen sulfide (H2S), a major odorous component of waste gas from sewage treatment plants. A series of designed experiments is used to examine the effect on bacteria-immobilized activated carbon (termed "biocarbon") due to physical adsorption, chemical reaction, and microbial degradation in the overall removal of H2S. H2S breakthrough tests are conducted with various samples, including microbe-immobilized carbon and Teflon discs, salts-medium-washed carbon, and ultra-pure water-washed carbon. The results show a higher removal capacity for the microbe-immobilized activated carbon compared with the activated carbon control in a batch biofilter column. The increase in removal capacity is attributed to the role played by the immobilized microorganisms in metabolizing adsorbed sulfur and sulfur compounds on the biocarbon, hence releasing the adsorption sites for further H2S uptake. The advantage for activated carbon serving as the support medium is to adsorb a high initial concentration of substrate and progressively release this for microbial degradation, hence acting as a buffer for the microorganisms. Results obtained from surface area and pore size distribution analyses of the biocarbon show a correlation between the available surface area and pore volume with the extent of microbial immobilization and H2S uptake. The depletion of surface area and pore volume is seen as one of the factors which cause the onset of column breakthrough. Microbial growth retardation is due to the accumulation of metabolic products (i.e., sulfuric acid); and a lack of water and nutrient salts in the batch biofilter are other possible causes of column breakthrough.

Volatile organic compound adsorption in a gas-solid fluidized bed

Fluidization finds many process applications in the areas of catalytic reactions, drying, coating, combustion, gasification and microbial culturing. This work aims to compare the dynamic adsorption characteristics and adsorption rates in a bubbling fluidized bed and a fixed bed at the same gas flow-rate, gas residence time and bed height. Adsorption with 520 ppm methanol and 489 ppm isobutane by the ZSM-5 zeolite of different particle size in the two beds enabled the differentiation of the adsorption characteristics and rates due to bed type, intraparticle mass transfer and adsorbate-adsorbent interaction. Adsorption of isobutane by the more commonly used activated carbon provided the comparison of adsorption between the two adsorbent types. With the same gas residence time of 0.79 seconds in both the bubbling bed and fixed bed of the same bed size of 40 mm diameter and 48 mm height, the experimental results showed a higher rate of adsorption in the bubbling bed as compared to the fixed bed. Intraparticle mass transfer and adsorbent-adsorbate interaction played significant roles in affecting the rate of adsorption, with intraparticle mass transfer being more dominant. The bubbling bed was observed to have a steeper decline in adsorption rate with respect to increasing outlet concentration compared to the fixed bed. The adsorption capacities of zeolite for the adsorbates studied were comparatively similar in both beds; fluidizing, and using smaller particles in the bubbling bed did not increase the adsorption capacity of the ZSM-5 zeolite. The adsorption capacity of activated carbon for isobutane was much higher than the ZSM-5 zeolite for isobutane, although at a lower adsorption rate. Fourier transform infra-red (FTIR) spectroscopy was used as an analytical tool for the quantification of gas concentration. Calibration was done using a series of standards prepared by in situ dilution with nitrogen gas, based on the ideal gas law and relating partial pressure to gas concentration. Concentrations up to 220 ppm for methanol and 75 ppm for isobutane were prepared using this method.

Removal of odorous sulphur-containing gases by a new isolate from activated sludge

Biological treatment of odorous sulphur-containing compounds is attracting attention due to its benign eco-friendliness, energy-savings and low operating costs. As the biological treatment efficiency of dimethylsulphide (DMS) reported was often low and variable, selection of useful DMS-degrading microorganisms is of importance for the enhancement of the biological deodorizing process. This paper reports the successful isolation of a DMS-degrading bacterium from activated sludge, using the enrichment isolation technique. The isolate was identified by 16S rRNA gene sequencing, and found to belong to the alpha group of Proteobacteria, with an identity of 99.4% and 99.1% to the 16S rRNA gene sequences of Afipia felis and Pseudomonas carboxydohydrogena, respectively. The isolate was able to metabolize DMS as well as hydrogen sulphide (H2S). A batch experiment was performed to assess the removal characteristics of DMS by the isolate. The results showed that over half of DMS could be removed by the isolate in 3 hours when the initial DMS amount was approximately 10 micromol and 25 micromol. Removal of H2S by the isolate was evaluated by a continuous test in a 2-L gas-bubbling bottle. Although part of the H2S removal by the mineral medium itself was observed in the control test, the majority of H2S removal was believed to be attributed to the metabolic activity of the isolate. In conclusion, the isolate might be potentially useful for the enhancement of the biological deodorizing processes.

Batch experiment on H2S degradation by bacteria immobilised on activated carbons

Biological treatments of odorous compounds, as compared to chemical or physical technologies, are in general ecologically and environmentally favourable. However, there are some inefficiencies relative to the media used in biofiltration processes, such as the need for an adequate residence time; the limited lifetime, and pore blockage of media, which at present render the technology economically non-viable. The aim of the study is to develop novel active media to be used in performance-enhanced biofiltration processes, by achieving an optimum balance and combination of the media adsorption capacity with the biodegradation of H2S through the bacteria immobilised on the media. An enrichment culture was obtained from activated sludges in order to metabolise thiosulphate. Batch-wise experiments were conducted to optimise the bacteria immobilisation on activated carbon, so as to develop a novel "biocarbon". Biofilm was mostly developed through culturing the bacteria with the presence of carbons in mineral media. SEM and BET tests of the carbon along with the culturing process were used to identify, respectively, the biofilm development and biocarbon porosity. Breakthrough tests evaluated the biocarbon performance with varying gas resistance time, inlet H2S concentration, and type of support materials. Fundamental issues were discussed, including type of support material, mode of bacteria immobilisation, pore blockages, and biodegradation kinetics, etc. This batch-wise study provides a basis for our future research on optimisation of the biofiltration process using a bio-trickling reactor.

Post-onset inhibition of murine arthritis using combined chemokine antagonist therapy

OBJECTIVE

To investigate the effect of targeting the chemotaxis of monocytes and polymorphonuclear monocytes (PMNs) in situ in MRL-Faslpr arthritis.

METHODS

MRL-Faslpr mice were injected intradermally with complete Freund's adjuvant and cellular infiltration into the joint was monitored. Once clinical disease developed, the animals received one of three treatments: MCP-1(9-76); MCP-1(9-76) plus Gro-alpha(8-73); or control peptide, MCP-1 Ala. The bimalleolar ankle width was measured for 11 days and histological examination of the joints was then assessed.

RESULTS

Cellular infiltration started after the onset of ankle swelling, and increased progressively. The incidence of swelling and the histopathology was reduced after day 6 of treatment in the MCP-1(9-76)-treated mice. Mice treated with the two antagonists MCP-1(9-76) and Gro-alpha(8-73) displayed a further significant reduction in disease parameters.

CONCLUSION

Treatment after disease onset with chemotactic antagonists for monocytes and PMNs significantly alleviated both the swelling and the histopathology seen in arthritis, suggesting that chemokine antagonists are an effective anti-inflammatory therapy.

Three-dimensional pseudospectral modelling of cardiac propagation in an inhomogeneous anisotropic tissue

Various investigators have used the monodomain model to study cardiac propagation behaviour. In many cases, the governing non-linear parabolic equation is solved using the finite-difference method. An adequate discretisation of cardiac tissue with realistic dimensions, however, often leads to a large model size that is computationally demanding. Recently, it has been demonstrated, for a two-dimensional homogeneous monodomain, that the Chebyshev pseudospectral method can offer higher computational efficiency than the finite-difference technique. Here, an extension of the pseudospectral approach to a three-dimensional inhomogeneous case with fibre rotation is presented. The unknown transmembrane potential is expanded in terms of Chebyshev polynomial trial functions, and the monodomain equation is enforced at the Gauss-Lobatto node points. The forward Euler technique is used to advance the solution in time. Numerical results are presented that demonstrate that the Chebyshev pseudospectral method offered an even larger improvement in computational performance over the finite-difference method in the three-dimensional case. Specifically, the pseudospectral method allowed the number of nodes to be reduced by approximately 85 times, while the same solution accuracy was maintained. Depending on the model size, simulations were performed with approximately 18-41 times less memory and approximately 99-169 times less CPU time.

A study of the mortality rate and life expectancy of the Chinese population over the last forty years

"In order to make up for the incompleteness of data in the last 40 years, this paper will try to make a preliminary study of the age-specific mortality rate and average life expectancy and its changing trends [for] the Chinese population over the last 40 years, based on the relevant data on mortality from sample surveys on fertility and birth control among Chinese women."