Carboxymethylated Abrus cantoniensis polysaccharide prevents CTX-induced immunosuppression and intestinal damage by regulating intestinal flora and butyric acid content

As a Chinese folk health product, Abrus cantoniensis exhibits good immunomodulatory activity because of its polysaccharide components (ACP), and carboxymethylation of polysaccharides can often further improve the biological activity of polysaccharides. In this study, we explored the impact of prophylactic administration of carboxymethylated Abrus cantoniensis polysaccharide (CM-ACP) on immunosuppression and intestinal damage induced by cyclophosphamide (CTX) in mice. Our findings demonstrated that CM-ACP exhibited a more potent immunomodulatory activity compared to ACP. Additionally, CM-ACP effectively enhanced the abundance of short-chain fatty acid (SCFA)-producing bacteria in immunosuppressed mice and regulated the gene expression of STAT6 and STAT3 mediated pathway signals. In order to further explore the relationship among polysaccharides, intestinal immunity and intestinal flora, we performed a pseudo-sterile mouse validation experiment and fecal microbiota transplantation (FMT) experiment. The findings suggest that CM-FMT and butyrate attenuate CTX-induced immunosuppression and intestinal injury. CM-FMT and butyrate show superior immunomodulatory ability, and may effectively regulate intestinal cell metabolism and repair the damaged intestine by activating STAT6 and STAT3-mediated pathways. These findings offer new insights into the mechanisms by which CM-ACP functions as functional food or drug, facilitating immune response regulation and maintaining intestinal health.

Unequivocal Identification of Spin-Triplet and Spin-Singlet Superconductors with Upper Critical Field and Flux Quantization

Spin-triplet superconductors play central roles in Majorana physics and quantum computing but are difficult to identify. We show the methods of kink-point upper critical field and flux quantization in superconducting rings can unequivocally identify spin-singlet, spin-triplet in centrosymmetric superconductors, and singlet-triplet admixture in noncentrosymmetric superconductors, as realized in γ-BiPd, β-Bi_{2}Pd, and α-BiPd, respectively. Our findings are essential for identifying triplet superconductors and exploring their quantum properties.

Characterization and macrophages immunomodulatory activity of two water-soluble polysaccharides from Abrus cantoniensis

The study aims to elucidate the physicochemical properties and immunomodulatory activity of two polysaccharides (ACP_t0 and ACP_t2) from Abrus cantoniensis. Results revealed that ACP_t0 with a molecular weight of 26.0 kDa, was mainly composed of glucose (83.1%) and galactose (6.1%), and that ACP_t2 with a molecular weight of 145.6/8.9 kDa, consisted of galactose (25.6%), galacturonic acid (22.2%), arabinos (16.6%) and galactose (11.0%) respectively. AFM and Congo red experiments suggested that ACP_t0 and ACP_t2 might be spherical particles with triple-helix conformation in aqueous solution. ACP_t0 and ACP_t2 exhibited immunomodulatory activity by promoting the proliferation, augmenting pinocytic and phagocytic capacities, releasing immunoactive molecules such as ROS, NO, iNOS, TNF-α, IL-6 and IL-1β, upregulation of the mRNA levels of corresponding cytokines in macrophages. Moreover, ACP_t0 and ACP_t2 were recognized by toll-like receptor 4 (TLR4) and exerted immunomodulatory effects via activating Myeloid differentiation factor 88 (MyD88), mitogen-activated protein kinases (MAPKs) and serine/threonine kinase (Akt) signaling pathways in macrophages. Notably, ACP_t2 had higher immunomodulatory activity than ACP_t0. Based on the present findings, ACP_t0 and ACP_t2 could be explored as an active component of immunomodulators in the food and pharmaceutical fields.

Effects of Different Sources of Calcium in the Diet on Growth Performance, Blood Metabolic Parameters, and Intestinal Bacterial Community and Function of Weaned Piglets

Despite a well-documented effect of calcium on the piglet's intestinal microbiota composition, it is less known about changes in microbial function or the effect of different sources of calcium. The experiment was designed to study the effects of dietary calcium from different sources on production, immune indexes, antioxidant capacity, serum biochemical indexes, and intestinal microflora of weaning piglets. A total of 1,000 piglets were randomly assigned to five groups (10 replicate pens per treatment with 20 pigs per pen) and fed diets supplemented with calcium carbonate, calcium citrate, multiple calcium, organic trace minerals, and different concentrations of acidifier. The results showed that the replacement of calcium carbonate with calcium citrate and multiple calcium had almost no significant difference in the growth performance of pigs compared with the control group, and only the diet of multiple calcium dramatically decreased the average daily feed intake (ADFI) compared to the calcium citrate diet on days 15-28 (p < 0.05). The five groups did not change the content of MDA, SOD, and GSH-Px (p > 0.10). A similar situation occurs in the immune function of the blood. There was no significant effect in immune indexes (IgA, IgG, and IgM) among different treatments after weaning at 6 weeks for piglets (p > 0.10). The 16S rRNA sequencing of ileal and cecal microbiota revealed that only the relative abundance of Actinobacteriota at the phyla level was significantly greater in the ileum of the A group compared to the other treatments (p < 0.05). There was a clear effect on seven bacteria in the top 30 genera of ileum and cecum for five groups (p < 0.05). The result of PICRUSt predicted that the intestinal microbe was mainly involved in carbohydrate and amino acid metabolism, membrane transport, and metabolism of cofactors and vitamins. Besides, adding calcium citrate to a weaned piglet diet is better than other choices from the third week to the fourth week. In conclusion, diets with different calcium sources changed ADFI and some intestinal microbial composition of weaned piglets but had little effect on intestinal microbial function.

The Protective Effects of Three Polysaccharides From Abrus cantoniensis Against Cyclophosphamide-Induced Immunosuppression and Oxidative Damage

This study was designed to systematically elucidate the immunomodulatory and antioxidant effects of three polysaccharide fractions (ACP₆₀, ACP₈₀, and ACP_t2) from Abrus cantoniensis on cyclophosphamide (CTX)-induced immunosuppressive mice. The experimental mice were divided into 12 groups, then modeled and administrated with different doses of three polysaccharides (50, 150, 300 mg/kg/day) by gavage. The results showed that ACP could markedly recover the CTX-induced decline in immune organ and hemocytes indexes and promote proliferation of splenocytes, earlap swelling rate, secretion of cytokines (TNF-α, IFN-γ, IL-1β, IL-6), and immunoglobulin (Ig-M and Ig-G). Additionally, ACP improved the enzymatic activities of T-SOD and GSH-PX greatly, while the level of MDA was significantly decreased in the liver. In particular, ACP_t2 had higher immunomodulatory and antioxidant activities than ACP₆₀ and ACP₈₀. Based on the present findings, ACP could be utilized as an efficacious candidate for immunomodulators and antioxidants, which provide a new application prospect in the food and pharmaceutical industries.

[Clinical characteristics of human adenovirus infection in hospitalized children with acute respiratory infection in Beijing]

Objective: To compare the clinical characteristics of different types of human adenovirus (HAdV) infection in hospitalized children with acute respiratory infection in Beijing, and to clarify the clinical necessity of adenovirus typing. Methods: In a cross-sectional study, 9 022 respiratory tract specimens collected from hospitalized children with acute respiratory infection from November 2017 to October 2019 in Affiliated Children's Hospital, Capital Institute of Pediatrics were screened for HAdV by direct immunofluorescence (DFA) and (or) nucleic acid detection. Then the Penton base, Hexon and Fiber gene of HAdV were amplified from HAdV positive specimens to confirm their HAdV types by phylogenetic tree construction. Clinical data such as laboratory results and imaging data were analyzed for children with predominate type HAdV infection using t, U, or χ² test. Results: There were 392 cases (4.34%) positive for HAdV among 9 022 specimens from hospitalized children with acute respiratory infection. Among those 205 cases who were successfully typed, 131 were male and 74 were female, age of 22.6 (6.7, 52.5) months,102 cases (49.76%) were positive for HAdV-3 and 86 cases (41.95%), HAdV-7, respectively, while 17 cases were confirmed as HAdV-1, 2, 4, 6, 14 or 21. In comparison of clinical characteristics between the predominate HAdV type 7 and 3 infection, significant differences were shown in proportions of children with wheezing (10 cases (11.63%) vs. 25 cases (24.51%)), white blood cell count >15 ×10⁹/L (4 cases (4.65%) vs.14 cases (13.73%)), white blood cell count <5×10⁹/L (26 cases (30.23%) vs.11 cases (10.78%)), procalcitonin level>0.5 mg/L (43 cases (50.00%) vs. 29 cases (28.43%)), multilobar infiltration (45 cases (52.33%) vs.38 cases (37.25%)), pleural effusion (23 cases (26.74%) vs. 10 cases (9.80%)), and severe adenovirus pneumonia (7 cases (8.14%) vs. 2 cases (1.96%)) with χ²=5.11, 4.44, 11.16, 9.19, 4.30, 9.25, 3.91 and P=0.024, 0.035, 0.001, 0.002, 0.038, 0.002, 0.048, respectively, and also in length of hospital stay (11 (8, 15) vs. 7 (5, 13) d, Z=3.73, P<0.001). Conclusions: HAdV-3 and 7 were the predominate types of HAdV infection in hospitalized children with acute respiratory tract infection in Beijing. Compared with HAdV-3 infection, HAdV-7 infection caused more obvious inflammatory reaction, more severe pulmonary symptoms, longer length of hospital stay, suggesting the clinical necessity of further typing of HAdVs.

[Clinical characteristics of children infected with different subtypes/genotypes of human respiratory syncytial virus in Beijing from 2009 to 2017]

Objective: To explore the different clinical characteristics of children infected with different subtype/genotype of human respiratory syncytial virus (HRSV) in Beijing. Methods: Respiratory specimens for positive HRSV were randomly collected from children with acute respiratory tract infection (ARTI) in the epidemic season of HRSV from November of each year to January of the next year during 2009 and 2017. G genes of HRSV were amplified and sequenced for subtyping and genotyping by bioinformatics analysis. Clinical data were collected and analyzed. Results: Out of 590 children, 376 (63.7%) with subtype A, and 214 (36.3) with subtype B. The annual dominant subtypes of HRSV from 2009 to 2017 were B-A-A-B-AB-A-A-B-A, respectively, whilst a total of 10 genotypes were detected with 95.8% assigned to genotype ON1 and NA1 of subtype A, and genotype BA9 of subtype B. Children infected with subtype B (96 cases, 44.9%) were more likely aged 0-3 month old than those with subtype A (118 cases, 31.4%) (P=0.001), and more likely to be admitted to Intensive Care Unit(ICU) ((124 cases, 57.9%) than those with subtype A (172 cases, 45.7%)) (P=0.005). Statistical significance were shown among children infected with genotype ON1, NA1 or BA9, in the possibility of infection in children aged 0-3 month (P=0.003), proportion of admission into ICU (P=0.007), length of stay in hospital (P=0.001), and clinical outcome (P=0.001), respectively. Conclusion: Children infected with different subtype or genotype of HRSV have different clinical characteristics, which stresses the important role of the monitoring HRSV subtypes and genotypes among children.

Rapid and accurate diagnosis of brain abscess caused by Nocardia asiatica with a combination of Ziehl-Neelsen staining and metagenomics next-generation sequencing

BACKGROUND AND PURPOSE

Early and accurate diagnosis is vital in cerebral nocardiosis, a very rare and infectious disease associated with a high mortality rate. Herein, we report a case that a patient with brain abscess was swiftly diagnosed and successfully treated.

METHODS

We report a case of a 61-year-old woman with a brain abscess caused by Nocardia asiatica, diagnosed by a combination of Ziehl-Neelsen staining and metagenomics next-generation sequencing (mNGS).

RESULTS

A 61-year-old woman with left breast cancer resection, diabetes mellitus and a 7-month discontinuous cough and fever was admitted to our hospital. On the third day of hospitalization, she experienced a sudden loss of consciousness and was diagnosed with a brain abscess and a pathological change in cerebral mass on brain magnetic resonance imaging (MRI). Due to the failure of culturing any microorganisms from the pup, the dissected sample from the patient with Ziehl-Neelsen staining tested positive for acid-fast bacilli and was subjected to mNGS. The pathogen was identified as N. asiatica and the patient was treated accordingly with linezolid and trimethoprim-sulfamethoxazole until complete recovery was confirmed by the follow-up cerebral MRI.

CONCLUSIONS

This is the first case report of a brain abscess caused by N. asiatica being swiftly diagnosed by a combination of Ziehl-Neelsen staining and mNGS. This rapid diagnosis allowed us to successfully treat this rare infection.

Main active components of Jiawei Gegen Qinlian decoction protects against ulcerative colitis under different dietary environments in a gut microbiota-dependent manner

As an effective drug against acute enteritis diarrhea, Gegen Qinlian decoction (GQD) has a history of 2000 years. However, the potential molecular mechanism through which GQD could protect intestinal barrier from ulcerative colitis (UC) still remains undefined. As an important part of the homeostasis of the colon, gut microbiota is closely related to the dynamic evolution of the surrounding environment and the adjustment of dietary structure. At present, the effectiveness and mechanism of Jiawei Gegen Qinlian decoction against UC in different dietary environments are not clear. Here, the main active components of Jiawei Gegen Qinlian Decoction (PBM), were selected to construct a reasonable and effective compound scheme. We adopted "5% dextran sulfate sodium (DSS)" and "high temperature and humidity + high sugar and high fat + alcohol + 5%DSS" to induce UC rat models in general environment and UC rat models in Lingnan area, respectively. Then, we examined the therapeutic effects of PBM (89.96 mg/kg and 179.92 mg/kg) on two kinds of UC rats. The role of gut microbiota in the anti-UC effect of PBM was identified by intestinal flora consumption and fecal microbiota transplantation (FMT) experiments. Subsequently, we monitored the alterations of gut microbiota and fecal metabolism in the rat colon by 16Sr DNA technique and targeted metabonomics, respectively. The colon inflammation of the PBM-treated and the FMT-treated rats both showed significant relief, as evidenced by a reduction in body weight loss, bloody stool, diarrhea, disease activity index (DAI) score, shortening of colon length as well as decreased colon histology damage. Interestingly enough, the depletion of intestinal flora took away the protective effect of PBM, confirming the importance of intestinal flora in the anti-UC effect of PBM. Then our findings suggested that PBM could not only regulate the gut microbiota by increasing Akkermansia and Romboutsia but also decrease Escherichia-Shigella. More importantly, PBM could increase the production of propionate and total short-chain fatty acids (SCFAs) in colitis rats, regulate medium and long chain fatty acids (M-LCFAs), maintain bile acids (BAs) homeostasis, and regulate amino acids (AAs) metabolism. The transformation of intestinal environment might be related to the upregulation of anti-inflammation, anti-oxidation and tight junction protein expression in colonic mucosa. In summary, PBM showed potential for anti-UC activity through gut microbiota dependence and was expected to be a complementary and alternative medicine herb therapy.

Absence of Evidence of Electrical Switching of the Antiferromagnetic Néel Vector

Much theoretical and experimental attention has been focused on the electrical switching of the antiferromagnetic (AFM) Néel vector via spin-orbit torque. Measurements employing multiterminal patterned structures of Pt/AFM show recurring signals of the supposedly planar Hall effect and magnetoresistance, implying AFM switching. We show in this Letter that similar signals have been observed in structures with and without the AFM layer, and of an even larger magnitude using different metals and substrates. These may not be the conclusive evidence of spin-orbit torque switching of AFM, but the thermal artifacts of patterned metal structure on substrate. Large current densities in the metallic devices, beyond the Ohmic regime, can generate unintended anisotropic thermal gradients and voltages. AFM switching requires unequivocal detection of the AFM Néel vector before and after SOT switching.

MiR-378 promotes the cell proliferation of non-small cell lung cancer by inhibiting FOXG1

OBJECTIVE

To identify the functioning mode of miR-378 on non-small cell lung cancer (NSCLC) and provide therapeutic targets for NSCLC.

PATIENTS AND METHODS

Expression levels of miR-378 in human NSCLC tissue samples and NSCLC-derived cell lines were measured by using quantitative Real-time polymerase chain reaction (PCR). Cell proliferation capacity was assessed by methyl thiazolyl tetrazolium (MTT) assay and colony formation assay. Cell apoptosis and cell cycle distribution were identified by flow cytometry. Downstream target gene was confirmed by using luciferase and Western blotting assays.

RESULTS

MiR-378 was significantly elevated in NSCLC tissues when compared with para-carcinoma tissues (n=42). Decreased-miR-378 could attenuate cell proliferation capacity, as well as promoted cell apoptosis and induced cell cycle arrest at G0/G1 phase. FOXG1 was chosen as the target gene of miR-378 by bioinformatics analysis and luciferase reporter assay. Moreover, restoration of miR-378 could impair the tumor suppression role of downregulated-miR-378 on NSCLC growth.

CONCLUSIONS

Decreased-miR-378 exerted tumor-suppressive effects on NSCLC growth via targeting FOXG1 in vitro, which provided an innovative and candidate target for diagnosis and treatment of NSCLC.

Competitive interaction on dual-species biofilm formation by spoilage bacteria, Shewanella baltica and Pseudomonas fluorescens

AIMS

This study aims to characterize the biofilm produced by mono- and dual-species of Shewanella baltica and Pseudomonas fluorescens as fish spoilers at the different incubation temperature, and to elucidate the interactive behaviour of dual-species biofilm development.

METHODS AND RESULTS

The mono- and dual-species biofilm formation and adhesion characteristics of S. baltica and P. fluorescens were evaluated by using crystal violet staining, scanning electron microscopy and confocal laser scanning microscopy. Results showed that P. fluorescens had significantly higher biofilm biomass and polysaccharides production than S. baltica, and two isolates reached the maximum biofilm biomass during the early stationary phase. Lower biomass and polysaccharides in dual-species biofilms were observed compared to mono-species of P. fluorescens. Meanwhile, S. baltica and P. fluorescens formed fragile and viscous pellicles with different spatial architectures respectively. In dual-species pellicle few large microcolonies were dominated by P. fluorescens. Compared to mono-species of PF07, adherent cell population and biofilm thickness at the developing phase significantly decreased, and biofilm-forming cycle prolonged in the dual-species biofilms. Biofilm formation and adhesion of mono- and dual-species at 4 or 15°C were significantly higher than at 30°C during the same phase. The culture supernatant extracts of the two spoilage strains greatly inhibited biofilm development to each other.

CONCLUSIONS

Shewanella baltica and P. fluorescens had different biofilm and pellicle characteristics, and the inhibitory development on dual-species biofilm was associated with the competitive interaction by the two psychrotrophic spoilage bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work contributes to a better understanding of interactive behaviour of multispecies biofilm communities by psychrotrophic spoilage bacteria at low temperature, which could contribute to further control contamination of spoilage organism during the preservation and processing of aquatic products.

SAR and QSAR study on the bioactivities of human epidermal growth factor receptor-2 (HER2) inhibitors

In this paper, structure-activity relationship (SAR, classification) and quantitative structure-activity relationship (QSAR) models have been established to predict the bioactivity of human epidermal growth factor receptor-2 (HER2) inhibitors. For the SAR study, we established six SAR (or classification) models to distinguish highly and weakly active HER2 inhibitors. The dataset contained 868 HER2 inhibitors, which was split into a training set including 580 inhibitors and a test set including 288 inhibitors by a Kohonen's self-organizing map (SOM), or a random method. The SAR models were performed using support vector machine (SVM), random forest (RF) and multilayer perceptron (MLP) methods. Among the six models, SVM models obtained superior results compared with other models. The prediction accuracy of the best model (model 1A) was 90.27% and the Matthews correlation coefficient (MCC) was 0.80 on the test set. For the QSAR study, we chose 286 HER2 inhibitors to establish six quantitative prediction models using MLR, SVM and MLP methods. The correlation coefficient (r) of the best model (model 4B) was 0.92 on the test set. The descriptors analysis showed that HAccN, lone pair electronegativity and π electronegativity were closely related to the bioactivity of HER2 inhibitors.

Regulatory Roles of Dclk1 in Epithelial Mesenchymal Transition and Cancer Stem Cells

The identification of functionally relevant subpopulations of therapy-resistant cancer cells is a challenge. These cells, intrinsically resistant to conventional therapy, can cause recurrence. Evidence has suggested that therapy-resistant cancer cells are likely epithelial–mesenchymal transition (EMT) cells and/or stem-like cells called cancer stem cells (CSCs). EMT, a normal embryological process that converts epithelial cells into mesenchymal cells, is frequently activated during cancer development and progression. CSCs are a small subpopulation of cancer cells within a tumor mass that have the ability to self-renew and maintain tumor-initiating capacity by giving rise to heterogeneous lineages of cancer cells that comprise the whole tumor. Although the origin of CSCs and EMT cells remains to be fully explored, a growing body of evidence has indicated that the biology of EMT and CSCs is strongly linked. Doublecortin-like kinase 1 (DCLK1), a cancer stem cell marker, is functionally involved in maintaining cancer stemness and the process of EMT important for cancer initiation, cancer metastasis, and secondary tumor formation. Therefore, targeting these cells may provide new strategies to overcome tumor heterogeneity, therapeutic resistance, and cancer relapse. In this review, we will provide a potential mechanistic link between EMT induction and the emergence of CSCs for the origin and progression of cancer. We will highlight the functional activity of DCLK1 in supporting EMT and cancer cell self-renewal, which will lead us to a better understanding of DCLK1 expression in cancer development and progression, and help us to develop targeted therapies for effective cancer treatment.

Glial cell line-derived neurotrophic factor promotes β-catenin phosphorylation and nuclear translocation in glioma cells

AIM

Glial cell line-derived neurotrophic factor (GDNF) and N-cadherin interact to transduce intracellular signals. However, the specific molecular mechanisms of this interaction are unclear. This study attempted to detect changes in GDNF-induced β-catenin phosphorylation and nuclear translocation in C6 glioma cells.

METHODS

C6 glioma cells were treated with GDNF (70 ng/mL) and membrane and cytoplasmic proteins were extracted. A N-cadherin antibody was used for co-immunoprecipitation (co-IP). Western blot analysis using the co-IP protein was completed using antibodies for β-catenin, Src and β-actin. Immunocytochemistry was conducted with the same antibodies. To determine if Src induced phosphorylation of β-catenin Tyr-654, Western blot analysis was also performed on nuclear proteins from C6 cells treated with tyrosine kinase inhibitor PP2 using then p- β-catenin antibody.

RESULTS

After induced by GDNF, C6 cell membrane β-catenin was phosphorylated at Tyr-654 and subsequently separated from the N-cadherin/β-catenin complex. Further study confirmed that the induction by GDNF significantly increased cytoplasmic and nuclear expression of phospho-β-catenin (Tyr-654) in C6 glioma cells. There was also an increase in the binding of non-receptor protein kinase Src with N-cadherin on the inner cell membrane surface. Src induced phosphorylation of β-catenin Tyr-654 induced by GDNF decreased significantly.

CONCLUSION

The results of our study demonstrate that GDNF increases the intracellular phosphorylation level of β-catenin through N-cadherin/Src signaling, which subsequently stimulates the nuclear translocation of β-catenin. This study provides a theoretical basis for us to reveal the role of biological mechanisms on glioma cell by GDNF.

Psychotropic drugs for the management of cancer-related fatigue: a systematic review and meta-analysis

Cancer-related fatigue (CRF) is a common symptom affecting 60-90% of cancer survivors, and effective management for CRF is not yet available. Recently, an increasing number of trials examining the use of psychotropic drugs for the treatment of CRF have been performed, but these trials have yielded inconsistent results. Therefore, we conducted a meta-analysis aimed at assessing the effect and safety of psychotropic drugs for the management of CRF. Ten eligible trials of the psychotropic drugs methylphenidate and modafinil in a total of 1582 participants treated for CRF were subjected to statistical analyses. A meta-analysis of seven of these studies indicated that methylphenidate was superior to placebo for the treatment of CRF. Another meta-analysis of three studies evaluating modafinil found that this drug was no better than placebo. Adverse events were similar between both methylphenidate and modafinil and the placebo groups. Our meta-analysis indicated that the treatment of CRF with methylphenidate appears to be effective, whereas modafinil provides no benefit. These results of this analysis warrant further trials to confirm the efficacy and safety of psychotropic drugs for the treatment of CRF.

The dynamic dielectric at a brain functional site and an EM wave approach to functional brain imaging

Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging.

Physical origins of the new magnetoresistance in Pt/YIG

A new type of magnetoresistance (MR) observed in Pt/YIG when nominally nonmagnetic Pt comes in contact with a ferrimagnetic insulator yttrium iron garnet (YIG) has drawn intense experimental and theoretical interest. In this Letter, we experimentally demonstrate two physical origins of the new MR: a spin current across the Pt/YIG interface and the magnetic proximity effect. The new MR can also be reproduced when Pt is in contact with a nonmagnetic insulator doped with a few percent of Fe impurities. By tuning the YIG surface and inserting an Au layer between the Pt and YIG, we are able to separate the two contributions.

Effects of exogenous 5-aminolevulinic acid on PIP1 and NIP aquaporin gene expression in seedlings of cucumber cultivars subjected to salinity stress

Aquaporins play a direct role in plant water relation under salt stress, but the effects of 5-aminolevulinic acid (ALA) on aquaporin gene expression in salt-treated plants remain unknown. This study investigated the potential effects of exogenous ALA (50 mg/dm3) on aquaporin expression levels under salt stress (75 mM NaCl) in the salt-sensitive (Jinchun No.4) and the relatively salt-tolerant cucumber (Jinyou No.1) seedlings. The expressions of cucumber PIP aquaporin gene (CsPIP1:1) and cucumber NIP aquaporin gene (CsNIP) were analyzed in 20-day-old seedling leaves at 2, 4, 8, 16, and 24 h after ALA treatment. After treatment with saline alone and ALA alone, CsPIP1:1 and CsNIP gene expression levels in the 2 cucumber cultivars increased to maximum at 2 h. The aquaporin gene expression in salt-treated cucumber seedling leaves was considerably higher than that in leaves subjected to exogenous ALA. Further, the aquaporin expression levels in Jinchun No.4 were higher than those in Jinyou No.1, reaching 5.20- and 2-fold induction levels, respectively. After treatment with both ALA and NaCl, the CsNIP gene expression was downregulated in both the cucumber cultivars, while that of CsPIP1:1 decreased at 2 h and then increased to 3.8-fold in Jinchun No.4. In Jinyou No.1, CsPIP1:1 gene expression gradually increased to 2.3-fold at 4 h, followed by a decline in expression. The results indicated that ALA might delay and counteract the upregulated expression of CsPIP1:1 and CsNIP genes in cucumber seedlings under NaCl stress. Thus, salt tolerance of cucumber seedlings might be enhanced by ALA application.

Inverse spin Hall effect in a ferromagnetic metal

The inverse spin Hall effect (ISHE) has been observed only in nonmagnetic metals, such as Pt and Au, with a strong spin-orbit coupling. We report the observation of ISHE in a ferromagnetic permalloy (Py) on ferromagnetic insulator yttrium iron garnet (YIG). Through controlling the spin current injection by altering the Py-YIG interface, we have isolated the spin current contribution and demonstrated the ISHE in a ferromagnetic metal, the reciprocal phenomenon of the anomalous Hall effect. A large spin Hall angle in Py, determined from Py thin films of different thicknesses, indicates many other ferromagnetic metals may be exploited as superior pure spin current detectors and for applications in spin current.

Intrinsic spin Seebeck effect in Au/YIG

The acute magnetic proximity effects in Pt/YIG compromise the suitability of Pt as a spin current detector. We show that Au/YIG, with no anomalous Hall effect and a negligible magnetoresistance, allows the measurements of the intrinsic spin Seebeck effect with a magnitude much smaller than that in Pt/YIG. The experiment results are consistent with the spin polarized density functional calculations for Pt with a sizable and Au with a negligible magnetic moment near the interface with YIG.

Transport magnetic proximity effects in platinum

Platinum (Pt) metal, being nonmagnetic and with a strong spin-orbit coupling interaction, has been central in detecting the pure spin current and establishing most of the recent spin-based phenomena. Magnetotransport measurements, both electrical and thermal, conclusively show strong ferromagnetic characteristics in thin Pt films on the ferromagnetic insulator due to the magnetic proximity effects. The pure spin current phenomena measured by Pt, including the inverse spin Hall and the spin Seebeck effects, are thus contaminated and not exclusively established.

Isolation and characterization of the organ-specific and light-inducible promoter of the gene encoding rubisco activase in potato (Solanum tuberosum)

Constitutive promoters have been widely used in crop biotechnology applications. Tissue-specific or inducible promoters, however, have advantages in some cases. We isolated the 731-bp 5' flanking sequence of a potato (Solanum tuberosum) gene, encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) activase (RCA), which was isolated by genome walking. By using GUS as a reporter and with Northern blot analysis, the 702-bp fragment (referred to as StRCAp), ranging from nt -731 to -30 relative to the initiation code of the RCA gene, was analyzed in transgenic tobacco plants. The activity of StRCAp in leaves was 0.4-fold less than that of cauliflower mosaic virus 35S promoter, and was expressed throughout the green part of the light-grown transgenic T(1) seedlings, including cytoledons, leaves and young stems, but not roots. Further deletion analysis revealed that a shorter fragment (nt -249 to -30, StRCAp2) retained light-inducible features in cytoledons and leaves, but showed no detectable activity in young stems and roots. Although the activity of StRCAp2 in leaves was reduced significantly compared with that of StRCAp, the overall data indicated that cis-elements sufficient to regulate organ-specific and light-inducible transcription are within the 220-bp fragment. There is potential for application of StRCAp in plant genetic engineering.

Low temperature magnetothermoelectric effect and magnetoresistance in Te vapor annealed Bi2Te3

The electrical properties of single crystals of p-type Bi(2)Te(3) are shown to be tuned by annealing as-grown crystals in elemental Te vapor at temperatures in the range of 400-420 °C. While as-grown nominally stoichiometric Bi(2)Te(3) has p-type conductivity below room temperature, Te vapor annealed Bi(2)Te(3) shows a cross over from p- to n-type behavior. The temperature dependent resistivity of the Te annealed crystals shows a characteristic broad peak near 100 K. Applied magnetic fields give rise to a large low temperature magnetothermoelectric effect in the Te annealed samples and enhance the low temperature peak in the resistivity. Further, Te annealed Bi(2)Te(3) shows a large positive magnetoresistance, ∼ 200% at 2 K, and ∼ 15% at room temperature. The annealing procedure described can be employed to optimize the properties of Bi(2)Te(3) for study as a topological insulator.

Desalination of brackish groundwater by direct contact membrane distillation

The direct contact membrane distillation (DCMD) applied for desalination of brackish groundwater with self-made polyvinylidene fluoride (PVDF) membranes was presented in the paper. The PVDF membrane exhibited high rejection of non-volatile inorganic salt solutes and a maximum permeate flux 24.5 kg m(-2) h(-1) was obtained with feed temperature at 70 degrees C. The DCMD experimental results indicated that the feed concentration had no significant influence on the permeate flux and the rejection of solute. When natural groundwater was used directly as the feed, the precipitation of CaCO(3) would be formed and clog the hollow fibre inlets with gradual concentration of the feed, which resulted in a rapid decline of the module efficiency. The negative influence of scaling could be eliminated by acidification of the feed. Finally, a 250 h DCMD continuous desalination experiment of acidified groundwater with the concentration factor at constant 4.0 was carried out. The permeate flux kept stable and the permeate conductivity was less than 7.0 microS cm(-1) during this process. Furthermore, there was no deposit observed on the membrane surface. All of these demonstrated that DCMD could be efficiently used for production of high-quality potable water from brackish groundwater with water recovery as high as 75%.

Regulated endothelial protein C receptor shedding is mediated by tumor necrosis factor-alpha converting enzyme/ADAM17

Endothelial protein C receptor (EPCR) plays an important role in the protein C anticoagulation pathway. Previously, we have reported that EPCR can be shed from the cell surface, and that this is mediated by an unidentified metalloproteinase. In this study, we demonstrate that tumor necrosis factor-alpha converting enzyme/ADAM17 (TACE) is responsible for EPCR shedding. Phorbol-12-myristate 13-acetate (PMA)-stimulated EPCR shedding is reduced by approximately 50% in HEK293 cells transfected with human EPCR cDNA and by 60% in human umbilical vein endothelial cells after transfection of TACE small interfering RNA (siRNA) into these cells. PMA-stimulated EPCR shedding is completely blocked in fibroblasts from TACE-deficient mice transfected with human EPCR cDNA, and restored by transfection of TACE cDNA into this cell line. To characterize the EPCR sequence requirement for shedding, we generated several mutants of EPCR. Replacing amino acids from residue 193 to residue 200 with the FLAG sequence (DYKDDDDK) completely blocks EPCR shedding, whereas a single amino acid substitution in this region has less effect on EPCR shedding.

Long-Range Interactions between Soft Colloidal Particles in Slit−Pore Geometries

Combining theoretical and experimental techniques, we investigate the structure formation of charged colloidal suspensions of silica particles in bulk and in spatial confinement (slit-pore geometry). Our focus is to identify characteristic length scales determining typical quantities, such as the position of the main peak of the bulk structure factor and the period of the oscillatory force profile in the slitpore. We obtain these quantities from integral equations/SANS experiments (bulk) and Monte Carlo simulations/colloidal probe-AFM measurements (confinement), in which the theoretical calculations are based on the Derjaguin-Landau-Verwey-Overbeck (DLVO) potential. Both in bulk and in the slitpore, we find excellent qualitative and quantitative agreement between theory and experiment as long as the ionic strength chosen in the DLVO potential is sufficiently low (implying a relatively long-ranged interaction). In particular, the bulk properties of these systems obey the widely accepted density scaling of xi proportional to phi(-1/3). On the other hand, systems with larger ionic strengths and, consequently, more short-ranged interactions do not obey such power law behavior and rather resemble an uncharged hard-sphere fluid, in which the relevant length scale is the particle diameter.

The Ser219-->Gly dimorphism of the endothelial protein C receptor contributes to the higher soluble protein levels observed in individuals with the A3 haplotype

The endothelial cell protein C receptor (EPCR) plays an important role in regulating blood coagulation and in activated protein C-mediated anti-inflammatory and antiapoptotic processes. Recent studies reported that there are polymorphisms in the human EPCR gene. One of the polymorphisms (haplotype A3) results in substitution of the Ser at residue 219 with Gly in the transmembrane domain. This haplotype is associated with increased plasma levels of soluble EPCR and is a candidate risk factor for thrombosis. We established stable cell lines expressing either the EPCR A1 (Ser at residue 219) or A3 (Gly at residue 219) haplotype. Both constitutive and PMA-stimulated shedding are five- to sevenfold higher in the A3 cell line than the A1 cell line. We also isolated human umbilical vein endothelial cells (HUVEC) from A1/A1 or A1/A3 origins. PMA-stimulated shedding is fourfold higher in HUVEC derived from A1/A3 origin than from A1/A1 origin. After PMA treatment, the rate of human protein C activation decreased 36% in HUVEC derived from A1/A3 origin, while it only decreased 18% in HUVEC derived from A1/A1 origin. These results indicate that the A3 haplotype does promote cellular shedding in either 293 or endothelial cells and therefore is likely directly contributory to the higher soluble EPCR levels seen in patients carrying this haplotype.

Selective functional deficit in dendritic cell--T cell interaction is a crucial mechanism in chronic hepatitis B virus infection

A defect in specific T cell immunity has long been assumed to be the central mechanism of persistent Hepatitis B virus (HBV) infection. Recent studies on HBV transgenic mice have suggested, however, that functional deficit of dendritic cells (DC) was an underlying cause for the T cell dysfunction. The functions of monocyte-derived DC were determined by studying 75 subjects that included chronic hepatitis B patients with low or high HBV load; antibody to hepatitis B surface antigen (anti-HBs) positive individuals who had recovered completely from previous acute HBV infection; healthy donors who had received hepatitis B vaccination and were anti-HBs positive; and immunologically naïve to HBV or the vaccine individual. Impaired interactions between monocyte-derived DC and T cells were shown in chronic HBV infection patients, especially in those with active virus replication. The dysfunctions included: (i) failure of DC to increase human leukocyte antigen (HLA-II), B7 expression and interleukin-12 secretion in responses to hepatitis B surface antigen (HBsAg), (ii) defective induction of T cell proliferative response to HBsAg, (iii) failure to activate T cells to produce cytokines and (iv) deficit in the induction of antigen specific cytotoxic T lymphocytes (CTLs). In vitro treatment of DC with tumour necrosis factor-alpha improved HLA-II and B7 expression, as well as Th cell and CTL responses. It is concluded that defective DC-T cell interactions may account for the specific T cell immune defects in chronic HBV infection. Immunotherapy that aims at restoring DC functions could offer a new opportunity for effectively managing persistent HBV infections.

[Microbial reduction ability of various iron oxides in pure culture experiment]

The microbial reduction of ferrihydrite, lepidocrocite, hematite, goethite and aluminum-substituted iron oxides were examined by iron-reducer GS-15 under anaerobic pure culture condition. The results indicated that the ferrihydrite and lepidocrocite can be rapidly reduced by iron-reducer, and the percentage of microbial reduction are respectively 95.4% and 95.8% after 4 days incubation at 25 degrees C. The other iron oxides like hematite, Al-hematite, goethite and Al-goethite are very difficult to reduce during short-term incubation. The amounts of Fe(III)-reducing, Fe(II)-producing and Fe-reducing calculated by acetate consumption are identical under the conditions of lower concentration iron oxides addition.

A 23bp insertion in the endothelial protein C receptor (EPCR) gene impairs EPCR function

EPCR is a type I transmembrane protein, highly expressed on the endothelium of large vessels, that binds protein C and augments its activation. In this study, a 23bp insertion in the EPCR gene was found in 4/198 survivors of myocardial infarction and 3/194 patients with deep vein thrombosis. The EPCR gene with the insertion predicts a protein that lacks part of the extracellular domain, the transmembrane domain and the cytoplasmic tail. Expression studies showed that the truncated protein is not localized on the cell surface, cannot be secreted in the culture medium, and does not bind activated protein C. Since protein C activation depends on the concentration of EPCR, patients with the EPCR insertion could have a diminished protein C activation capacity. Further clinical studies of adequate samples size are necessary to establish whether or not the EPCR insertion predisposes to the development of thrombotic events.

[Anterior thoracolumbar K-plate fixation system: design and clinical application]

OBJECTIVES

To develop an anterior thoracolumbar K-plate fixation system and to report its preliminary clinical application.

METHODS

The K-plate system was developed with titanium alloy(TC4, Ti6A14V) and self-locking screw design was used. In 23 cases treated with this system, 13 had thoracolumbar fracture, 9 tuberculosis, and back syndrome after lumbar TFC operation.

RESULTS

All the 23 cases were followed up for one to ten months, averaging 4.5 months. In the 13 cases of fracture, body height of injured vertebra were regained completely, and neurologic deficits improved 2.1 grades in Frankel scale. In the 9 cases of tuberculosis, neurologic functions recovered and no local recurrence was noted. In one case of back syndrome, symptoms and signs did not occur after anterior TFC removal, interbody fusion, and K-plate fixation. This patient received second operation to remove K-plate 3 months after solid osseous fusion, and no electric erosion or obvious tissue reaction was found. 18 of the 23 cases were followed up for four months or more, and solid fusion was found in these patients in three to four months after surgery. No early complications related to implant were noted during the follow-up.

CONCLUSION

This K-plate system is suitable for reconstruction of thoracolumbar stability after anterior decompression in indicated patients.

[Development and clinical application of posterior STBtrade mark thoracolumbar transpedicular screw-plate fixation system]

OBJECTIVE

To develop a posterior STBTM thoracolumbar transpedicular screw-plate system and to apply it clinically.

METHODS

A posterior STBTM thoracolumbar transpedicular screw-plate system was developed with titanium alloy (TC4, Ti64A14V) and was used, from December 1999 to July 2000, to treat 63 cases with thoracolumbar or lumbar injuries or diseases, including thoracolumbar fracture/dislocation (33 cases), lumbar spondylosis and spondylolisthesis (16 cases), lumbar spondylosis and disk protrusion (6 cases), degenerative lumbar instability (4 cases), kyphosis due to ankylosing spondylitis (2 cases), and tuberculosis of spine (2 cases).

RESULTS

The 33 cases with thoracolumbar fracture/dislocation showed perfect reduction and fixation after the operation. The height of injured vertebral bodies returned to normal. One month later, all patients with neurological deficits, except the 6 cases with neurological deficits of Frankel grade A, showed improvement by 1 approximately 3 Frankel grades. The radicular symptoms in the 26 patients with lumbar spondylolisthesis, lumbar spondylosis and disk protrusion, and degenerative lumbar instability disappeared after operation. Among those cases, complete reduction was achieved in the 7 cases with grade I spondylolisthesis and 7 out of the 9 cases with grade II spondylolisthesis, and incomplete reduction (grade I) was seen in the remaining 2 cases with grade II spondylolisthesis. Forty cases were followed up for 5 months or over in out-patient department, no complication was found.

CONCLUSION

The posterior STBTM thoracolumbar transpedicular screw-plate system has the advantages of biological stability, excellent reduction capacity, easiness of operation, and positive clinical effectiveness.

[The inhibitory effect of oxymatrine on hepatitis C virus in vitro]

OBJECTIVE

To study the inhibitory effect of oxymatrine on HCV in vitro.

METHODS

SMMC-7721 cells transfected with pBK-HCV using lipofectin transfection protocal were treated with oxymatrine. bDNA signal amplification assay and MTT colorimetric assay were used for intracellular HCV RNA and cytotoxicity.

RESULTS

The stable HCV expression cell model established here could be used as a tool for medicine screen. Oxymatrine at the concentration of 100~1000 mug/ml could significantly decrease the level of intracellular HCV RNA. No cytotoxicity was shown in such concentrations.

CONCLUSIONS

Oxymatrine has an anti-HCV potential activity in vitro.

[Construction of plasmid gene bank of V. cholerae O139 and detection of O-antigen genes]

Because O-antigen biosynthesis genes are a tandem gene cluster. Gnomic fragments of 4-20 kilobases (kb) were obtained by digesting genomic DNA of V. cholerae O139 with restriction endonuclease EcoRI, then plasmid gene bank was constructed. Recombinant colony, E. coli DH5 alpha (pMG320), expressing O-antigen of V. cholerae O139 was detected from the bank by immunological agglutinative reaction. The futher analysis showed O-antigen expressed by recombinant colony had both immunogenicity and reactogenicity, and the size of O-antigen biosynthesis genes was about 4.6 kb.

Cloning and Expression of Chinese Duck Interferon-gamma Gene

The efficacy of cytokine therapy has been demonstrated in several viral diseases. Interferon-gamma is a cytokine that has potent antiviral property and immunomodulatory activity. To investigate the role of IFN-gamma in viral clearance during natural infection and to define the antiviral mechanism, DHBV-infected ducks was used as an animal model. To clone, express, and develop the method of quantifying DuIFN-gamma gene transcription and expression, DuIFN -gamma cDNA was amplified by RT-PCR from PHA stimulated duck PBMC. Recombinant plasmid expressing DuIFN-gamma was used to transfect COS-7, and the cell culture supernatant was analyzed by CPE inhibitory assay and MTT methods to determine the antiviral titer of IFN-gamma. The GST-DuIFN-gamma fusion protein was expressed in E.coli and purified using the GST sepharose 4B. Results indicated that the supernatant collected from COS-7 cells transfected with DuIFN-gamma cDNA was able to prevent duck fibroblasts from VSV induced CPE in a dose dependent manner. An anti-DuIFN-gamma antibody neutralized this antiviral activity.

Characterization of [Phe(13), Tyr(19)]-MCH analog binding activity to the MCH receptor

Melanin concentrating hormone (MCH), a hypothalamic neuropeptide, is an important regulator of energy homeostasis in mammals. Characterization of an MCH specific receptor has been hampered by the lack of a suitable radioligand. The [Phe(13), Tyr(19)]-MCH analog has been shown by different investigators to bind specifically to cell lines of epithelial or pigment cell origin. Recently, using functional assays, the MCH receptor has been characterized as a seven transmembrane G-coupled protein initially identified as SLC-1. In the present study, we used tyrosine iodinated [Phe(13), Tyr(19)]-MCH analog, which stimulates food intake in a manner similar to that of MCH, as well as native MCH to conduct binding studies. Specific binding could not be demonstrated in intact cells of several cell lines, including A431 and B16. Specific binding associated with membranes localized to the microsomal, not the plasma membrane, fraction. Message for SLC-1 was absent in these cell lines, as assessed by Northern blot analysis. We conclude that cells previously reported to express the MCH receptor do not express SLC-1 and that both iodinated MCH and the [Phe(13), Tyr(19)]-MCH have a large component of non-specific binding. These ligands may be useful for binding studies in transfected cells with high levels of SLC-1 expression. However they do not appear to be suitable for screening for the MCH receptor as most cells demonstrate significant low affinity non-specific binding.