Effect of water-soluble P-chitosan and S-chitosan on human primary osteoblasts and giant cell tumor of bone stromal cells

Water-soluble phosphorylated chitosan (P-chitosan) and disodium (1 → 4)-2-deoxy-2-sulfoamino-β-D-glucopyranuronan (S-chitosan) are two chemically modified chitosans. In this study, we found that P-chitosan significantly promotes cell proliferation of both human primary osteoblasts (OBs) and the OB like stromal cell component of the giant cell tumor of bone (GCTB) cells at the concentration from 125 to 1000 µg ml⁻¹ at all time points of 1, 3, 5 and 7 days after treatment. Further investigation of the osteogenic effect of the P-chitosan suggested that it regulates the levels of osteoclastogenic factors, receptor activator of nuclear factor kappa B ligand and osteoprotegerin expression. An interesting finding is that S-chitosan at lower concentration (100 µg ml⁻¹) stimulates cell proliferation while a higher dose (1000 µg ml⁻¹) of S-chitosan inhibits it. The inhibitory effect of S-chitosan on human primary GCT stromal cells was greater than that of OBs (p < 0.05). Taken together, our findings elucidated the osteogenic effect of P-chitosan and the varying effects of S-chitosan on the proliferation of human primary OBs and GCT stromal cells and provided us the rationale for the construction of novel bone repair biomaterials with the dual properties of bone induction and bone tumor inhibition.

Peroxiredoxins in colorectal neoplasms

Peroxiredoxins (Prxs) are novel group proteins with efficient antioxidant capacity, and some of them also have effects on cell proliferation, differentiation, apoptosis, and chemotherapy and radiotherapy resistance. Altogether six distinct Prxs expressions were investigated in histological samples of colorectal neoplasm and the distant normal tissues and investigated associatedly with parameters such as clinical stage and lymphnodes metastasis. Normal colorectal tissues were almost negative for Prxs, except Prx4 (15/32). In colorectal cancer tissues, the most prominent reactivity was observed with Prx2 in 23/32 cases, while the corresponding figures for others was 21/32 (Prx1), 18/32 (Prx3, Prx5, Prx6) and 8/32 (Prx4). Prx1 (P=0.023), Prx2 (P=0.012), and Prx5 (P=0.028) were the isoforms that showed significantly increased expression in colorectal cancer patients with stage III or lymphnodes metastasis-positive cases. There was a significant relationship between the expression of Prx1 and Prx2 (rs=0.425, P=0.015) and between Prx3 and Prx4 (rs=0.364, P=0.041). Additionally, 8 cases were studied by western analysis. Prx1, 2, 3, 5 and 6 were particularly elevated in tumors compared to nonmalignant tissue as assessed by immunohistochemistry. It appeared that some Prxs were upexpression in colorectal cancer tissues and may have some prognostic significance; the induction of Prxs could be explained by increased production of reactive oxygen species in carcinomatous tissue.

Identification of the forensically important sarcophagid flies Boerttcherisca peregrina, Parasarcophaga albiceps and Parasarcophaga dux (Diptera: Sarcophagidae) based on COII gene in China

Accurate species identication is a crucial step in forensic entomology, as the insect collected on a corpse can provide useful information for estimation of postmortem interval (PMI). The utility of the forensically important Sarcophagidae (Diptera) for crime scene investigation has been severely restricted, as morphological identification is difficult, especially the identification of females and larvae. In this study, a method for using mitochondrial DNA (mtDNA) sequence data and phylogenetic analysis was performed to distinguish the three Chinese sarcophagid species: Boerttcherisca peregrina (Robineau-Desvoidy, 1830) Parasarcophaga albiceps (Meigen, 1826) and Parasarcophaga dux (Thompson, 1869) (Diptera: Sarcophagidae). DNA was extracted and analyzed by a 189 bp fragment of cytochrome coxidase subunit II (COII) gene. The monophyletic branches of the phylogenetic tree reveal that this marker is suitable for discrimination between these species, providing high support for separation on congeneric species. Therefore, the molecular method applied to the sarcophagid species identification is feasible.

Screen of micro-organisms for inducing the production of dragon's blood by leaf of Dracaena cochinchinensis

AIMS

To screen micro-organisms for inducing the production of dragon's blood, which is normally produced by stem xylem and by leaf of Dracaena cochinchinensis, and to evaluate the product by comparing with the standard.

METHODS AND RESULTS

Thirty microbial strains were isolated from D. cochinchinensis leaves. Three of them were confirmed to elicit the leaf of D. cochinchinensis producing dragon's blood after inoculation. Upon elicitation, all of the 6-month-old leaves of the inducible trees produced dragon's blood; 60-70% of the 1-year-old leaves elicited produced the resin. All the three strains were identified as Colletotrichum gloeosporioide by morphological and molecular methods. The leaf resin had a similar TLC profile and antioxidant activities to the standard resin. In particular, it had a higher total flavonol content and antimicrobial activity than the standard.

CONCLUSIONS

Upon the induction of the screened C. gloeosporioide mycelia, D. cochinchinensis leaf produced dragon's blood with higher total flavone content and antimicrobial activity than the standard dragon's blood.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work has provided a strategy for producing dragon's blood in a sustainable way using leaves of C. gloeosporioides by fungal elicitation.

Chemical composition and antioxidant, antimicrobial activities of the essential oils of Thymus marschallianus Will. and Thymus proximus Serg

Chemical composition and antioxidant, antimicrobial activities of the essential oils from Thymus marschallianus Will. and Thymus proximus Serg. growing in the wild in Xinjiang were studied. Samples were collected from the aerial parts of the plants with simultaneous distillation-extraction apparatus. The yields ranged between 1.22%+/- 0.01 and 0.16%+/- 0.01 (weight/dry weight), respectively, 53 and 60 kinds of volatiles, representing 99.6% and 99.7% of the essential oils, respectively, were identified in extracts from T. marschallianus and T. proximus by GC/MS analysis. The main components were Thymol (28.0% to 32.9%), p-Cymene (7.7% to 25.4%), and gamma-Terpinene (18.0% to 22.4%). Antioxidant activities of the oils were evaluated using metal chelating, reductive potential, 2,2-diphenyl-1-picrylhydrazyl, hydroxyl radical, and modified thiobarbituric acid reactive substances assay. Antimicrobial activities of the oils were investigated on Escherichia coli, Staphylococcus aureus, Bacillus subtilis, yeast, Rhizopus, and Penicillium. The inhibition zones (IZ) and minimum inhibitory concentration (MIC) values were 5.0 to 35.7 mm in diameter and 1.81 to 4.52 microL/mL, respectively.

PRACTICAL APPLICATION

Due to the economical impacts of spoiled foods and the consumer's concerns over the safety of foods, a lot of attention has been paid to naturally derived compounds. Fresh and dried Thymus species as well as their processed products have been widely used as flavorings since ancient times; however, during the last few decades, they also have become a subject for a search of natural antioxidants and antimicrobial agents. Biological activities of Thymus essential oils depend on their chemical composition, which is determined by the genotype and influenced by environmental conditions. Recent studies have showed that Thymus species have strong antimicrobial and antioxidant activities. To the best of our knowledge, the properties of Thymus species growing wild in the Xinjiang have not been reported before.

Molecular cloning and temporal-spatial expression of I element in gregarious and solitary locusts

It has been reported that many genes and small RNAs are associated with density-dependent polyphenism in locusts. However, the regulatory mechanism underlying gene transcription is still unknown. Here, by analysis of transcriptome database of the migratory locust, we identified abundant transcripts of transposable elements, which are mediators of genetic variation and gene transcriptional regulation, mainly including CR1, I, L2 and RTE-BovB. We cloned one I element, which represents the most abundant transcripts in all transposable elements, and investigated its developmental and tissue-specific expression in gregarious and solitary locusts. Although there are no significant differences of I element expression in whole bodies between gregarious and solitary locusts at various developmental stages, this I element exhibits high expression level and differential expression pattern between gregarious and solitary locusts in central and peripheral nervous tissues, such as brain, antenna and labial palps. These results suggest that I element is potentially involved in the response of neural systems to social environmental changes in locusts.

Geographic differences on accumulation of sugars and polyols in locust eggs in response to cold acclimation

The accumulation of low molecular weight sugars and polyols is one of major mechanisms hypothesized to increase cold tolerance in overwintering insects. But little is known about whether these sugars and polyols are involved in geographic variation of cold tolerance. In this study, we investigated accumulation patterns of eight low molecular weight sugars and polyols of eggs in tropical and temperate populations of the migratory locust, which exhibits between-population variation in cold tolerance, in response to cold acclimation (5, 0 and -5 degrees C). Excluding erythritol, the other seven carbohydrates were identified as possible cryoprotectants in locust eggs. Basal maximal and minimal concentrations were 45 microg/g wet weight for trehalose and 0.59 microg/g wet weight for glycerol. Most sugars and polyols were elevated after a -5 degrees C exposure. In a tropical population, fructose, glucose, sorbitol and myo-inositol were significantly accumulated by low temperature treatments, but glycerol was not. In the temperate population, glycerol, glucose, mannitol, sorbitol, myo-inositol were significantly accumulated but trehalose did not increase. Our results suggest different accumulation patterns of these carbohydrates of locust eggs between tropical and temperate populations and highlighted possible roles for them in geographic variation of cold tolerance in the migratory locust.

The availability of 16S rRNA for the identification of forensically important flies (Diptera: Muscidae) in China

Many species of Muscidae are cosmopolitan synanthropic insects. It is frequently found on dead bodies after death, so an accurate identification of each species is necessary for the correct estimation of the postmortem interval (PMI). Identification species of Muscidae is traditionally performed through their morphological features. However, the morphological similarity of Muscidae in the level of species usually poses a challenge for forensic entomologists. Therefore a molecular method used 16S rRNA sequence on mitochondrial DNA was established for species identification. In this study, a 289 base pair region of mitochondrial DNA (mtDNA) coding for 16S rRNA was investigated for identification of the following forensically important species of Muscidae. The specimens were from four genera, including 18 Musca domestica (Linnaeus, 1758), 2 Ophyra spinigera (Stein, 1910), 2 Ophyra chalcogaster (Wiedemann, 1824), 1 Morellia hortorum (Fallén, 1817), and 1 Fannia canicularis (Linnaeus, 1761). 16S rDNA region allowed the identification of these species of Muscidae, indicating the possibility of separation congeneric species with molecular method.

Expression and functional significance of Twist1 in hepatocellular carcinoma: its role in vasculogenic mimicry

The up-regulation and nuclear relocation of epithelial-mesenchymal transition (EMT) regulator Twist1 have been implicated in the tumor invasion and metastasis of human hepatocellular carcinoma (HCC). The term vasculogenic mimicry (VM) refers to the unique capability of aggressive tumor cells to mimic the pattern of embryonic vasculogenic networks. However, the relationship between Twist1 and VM formation is not clear. In this study, we explored HCC as a VM and EMT model in order to investigate the role of Twist1 in VM formation. We first examined the expression of Twist1 in human HCC samples and cell lines and found that Twist1 was frequently overexpressed in the nuclear relocation occurring in VM-positive HCCs (13/18 [72%]). Twist1 nuclear expression was likewise significantly associated with VM formation. Clinicopathological analysis revealed that both VM and Twist1 nuclear expressions present shorter survival durations than those without expression. We consistently demonstrated that an overexpression of Twist1 significantly enhanced cell motility, invasiveness, and VM formation in an HepG2 cell. Conversely, a knockdown of Twist1 by the short hairpin RNA approach remarkably reduced Bel7402 cell migration, invasion, and VM formation. Using chromatin immunoprecipitation, we also showed that Twist1 binds to the vascular endothelial (VE)-cadherin promoter and enhances its activity in a transactivation assay.

CONCLUSION

The results of this study indicate that Twist1 induces HCC cell plasticity in VM cells more through the suppression of E-cadherin expression and the induction of VE-cadherin up-regulation than through the VM pattern in vivo and in a three-dimensional in vitro system. Our findings also demonstrate a novel cogitation in cancer stem-like cell differentiation and that related molecular pathways may be used as novel therapeutic targets for the inhibition of HCC angiogenesis and metastasis.

Evaluation of InGaN/GaN light-emitting diodes of circular geometry

Blue GaN light emitting diodes (LEDs) in the shape of cuboids and circular disks have been fabricated by laser micromachining. The proposed circular geometry serves to enhance overall light extraction on a macro-scale and to improve uniformity of the emission pattern due to the rotational symmetry of the chip. Analysis of the chip shaping effect is carried out by ray-tracing simulations and further supported with mathematical modeling using ideal LED models, and subsequently verified with fabricated devices. In comparison, a 10% improvement in overall emission was observed for circular LEDs over the regular cuboids, consistent with simulations and calculations. The measured emission pattern from the circular LED confirms the axial symmetry of the emission beam.

Immunomodulatory drug FTY720 induces regulatory CD4(+)CD25(+) T cells in vitro

As a novel immunosuppressant, FTY720 (2-amino-2-(2-[4-octylphenyl] ethyl)-1, 3-propanediol hydrochloride) has been used to prevent the allograft rejection in organ transplantation. FTY720 can prolong markedly survival of the allograft by inducing apoptosis of reactive lymphocytes and by redirecting the homing of lymphocytes. However, as the archetype of a new class of immune modulators, the potential effect of FTY720 on the immune response needs to be elucidated further. In this study, FTY720 was added into the mixed lymphocyte reaction (MLR) consisting of murine splenocytes from BALB/c and C57BL/6, to observe its direct effect on the induction of CD4(+)CD25(+) regulatory T cells. It was demonstrated that the proportion of CD4(+)CD25(+) and CD4(+)CD25(+)forkhead box P3 (FoxP3)(+) T cells in MLR were increased significantly by FTY720 treatment, and the expression of FoxP3 mRNA in lymphocytes was also enhanced markedly by the drug. A synergetic effect was observed between FTY720 and co-stimulation blockades. Moreover, analysis of the function of FTY720-treated cells manifested an increased suppressive activity in an in vitro antigen-specific proliferation assay. In conclusion, FTY720 can increase the number and enhance the functional activity of CD4(+)CD25(+) regulatory T cells in MLR, and these FTY720-treated cells possess the activity to down-regulate the alloreactivity of lymphocytes, indicating its potential use for therapeutic purposes.

Design of vertically-stacked polychromatic light-emitting diodes

A new design for a polychromatic light-emitting diode (LED) is proposed and demonstrated. LED chips of the primary colors are physically stacked on top of each other. Light emitted from each layer of the stack passes through each other, and thus is mixed naturally without additional optics. As a color-tunable device, a wide range of colors can be generated, making it suitable for display purposes. As a phosphor-free white light LED, luminous efficacy of 30 lm/watt was achieved.

[Pilot study of differentiation of bone marrow derived mesenchymal stem cells into endothelial cells induced by B16 melanoma cells in vitro]

OBJECTIVE

Bone-marrow derived mesenchymal stem cells (BMSC) have the potential to differentiate into endothelial cells. The aim of the study was to investigate the induction process of BMSC by B16 melanoma cells in vitro and to analyze the role of VEGF-a in the process.

METHODS

A co-culture system containing BMSC and B16 melanoma cells based on transwell indirect model was established, and the induction process of BMSC by B16 melanoma cells was studied in vitro.

RESULTS

BMSC were isolated from the bone marrow of C57 mice. BMSC expressed CD105, CD90, CD73, CD44 and CD166, and acquired expressin of endothelial phenotype markers including VEGFR-1, VEGFR-2 and Factor VIII after co-culture with B16 melanoma cells for 48 hours. The expression level of VEGFR-2 would be double and Factor VIII threefold more by extending the co-culture time to 72 hours. In the co-culture system, B16 melanoma cells also up-regulated the expression of VEGF-a.

CONCLUSIONS

VEGF-a plays a significant role in the differentiation of BMSC into cells of endothelial phenotype, therefore, is important to tumor angiogenesis.

Siderophore production by the marine-derived Aureobasidium pullulans and its antimicrobial activity

Over 300 yeast strains isolated from different marine environments were screened for their ability to produce siderophore. Among them, only the yeast strain HN6.2 which was identified to be Aureobasidium pullulans was found to produce high level of the siderophore. Under the optimal conditions, this yeast strain could produce 1.1mg/ml of the siderophore. The crude siderophore produced by the yeast strain HN6.2 was able to inhibit cell growth of Vibrio anguillarum and Vibrio parahaemolyticus, isolated from the diseased marine animals.

[Correlation between expressions of matrix metalloproteinase-2 & 9 and vasculogenic mimicry in gastrointestinal stromal tumors]

OBJECTIVE

To study the correlation between the expression of matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor (VEGF) and vasculogenic mimicry (VM) in gastrointestinal stromal tumors (GIST).

METHODS

The immunohistochemical staining indices (SI) of MMP-2, MMP-9, VEGF were assessed on specimens of 84 human cases with GIST (21 VM-positive cases). Gelatin zymography analysis of the activity of MMP-2 and MMP-9 activities were performed on another 42 human cases of GIST with fresh tissue (22 VM-positive cases).

RESULTS

The staining indices (SI) of MMP-2 and MMP-9 were higher in the VM-positive group (4.10 +/- 2.05 and 3.43 +/- 1.89 respectively) than in the VM-negative group (2.98 +/- 1.97 and 2.38 +/- 1.84 respectively, both P < 0.05); there was no statistic difference in the SI of VEGF between VM-positive and VM-negative group. Gelatin zymography analysis showed that the activity of MMP-2 and MMP-9 were significantly higher in the VM-positive group (3.62 +/- 3.95 and 4.77 +/- 5.29 respectively) than in the VM-negative group (1.26 +/- 1.21 and 2.11 +/- 1.54 respectively, both P < 0.05).

CONCLUSION

The expression of MMP-2 and MMP-9 correlates with VM formation in GIST.

Microbial structure of nitrifying granules and their estrogens degradation properties

It has been known that endocrine disruption compounds such as natural estrogens estrone, 17beta-estradiol, estriol, and synthetic steroid 17a-ethynylestradiol can be degraded by nitrifying bacteria. The aim of this research was to test biodegradation of estrogens by microbial granules containing nitrifying bacteria. Cultivation of microbial granules was performed in sequencing batch reactor in model wastewater with carbon to nitrogen ratio of 100:30 by weight. After the system reached the steady state, the mean diameter of granules, sludge volume index of granular biomass, and biomass concentration were 0.6 mm, 22 mL g(-1) and 7 g L(-1), respectively. Nitrite was not detected in the effluent, and conversion of the consumed NH4+-N to NO3--N was 93%. Specific NO3--N production rate was 0.12 d(-1) at the constant NH4+- loading late of 0.9 g L d(-1). The presence of ammonium-oxidizing and nitrite-oxidizing bacteria was confirmed by fluorescence in situ hybridization with 16S rRNA-targeted oligonucleotide probes Nsm156 and Nit3. The estrogen biodegradation by the granules was conducted in batch experiments. The complete biodegradation of the mixture of estrone, 17beta-estradiol, estriol, and 17a-ethynylestradiol, 100 microg L(-1) each, by microbial granules was within 60 days. The order of biodegradation for estrogens by microbial granules was as follows: 17beta-estradiol-->estriol-->estrone-->17a-ethynylestradiol. The degradation rate constants of estrogens by microbial granules were 0.19 d(-1), 1.26 d(-1), 0.14 d(-1) and 0.11 d(-1) for estrone, 17beta-estradiol, estriol and 17a-ethynylestradiol, respectively.

MicroRNA-320 expression in myocardial microvascular endothelial cells and its relationship with insulin-like growth factor-1 in type 2 diabetic rats

1. The aim of the present study was to determine the role of myocardial microvascular endothelial cells (MMVEC) in impaired angiogenesis of type 2 diabetic Goto-Kakizaki (GK) rats. 2. A microRNA (miRNA) microarray was used to assess miRNA expression in MMVEC from GK and Wistar rats. Upregulation of miRNA-320 was observed in MMVEC from GK rats using real-time reverse transcription-polymerase chain reaction (RT-PCR). 3. So far, nine miRNAs have been reported to target angiogenic factors and/or receptors, including kinase insert domain containing receptor (Flk-1), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 1 receptor (IGF-1R). The predicted genes targeted by miR-320 include Flk-1, IGF-1 and IGF-1R. Western blot analysis and RT-PCR were used to analyse the protein and mRNA expression, respectively, of the putative genes IGF-1 and IGF-1R. The expression of IGF-1 and IGF-1R proteins decreased significantly in diabetic MMVEC. However, the expression of IGF-1 mRNA increased rather than decreased. The mRNA expression of IGF-1R did not differ significantly between diabetic and control MMVEC. 4. Transfection of an miR-320 inhibitor into MMVEC from GK rats confirmed that miR-320 impaired angiogenesis. The proliferation and migration of diabetic MMVEC improved after transfection of the miR-320 inhibitor. In addition, the miR-320 inhibitor significantly increased the expression of IGF-1 protein, but had no effect on the expression of IGF-1R. 5. Eleven miRNAs were upregulated in MMVEC from GK rats compared with those in Wistar rats: let-7e, miR-129, miR-291-5p, miR-320, miR-327, mir-333, miR-363-5p, miR-370, miR-494, miR-503 and miR-664. 6. The results indicate that upregulation of miR-320 in MMVEC from GK rats may be responsible for the inconsistency between the expression of IGF-1 protein and mRNA and therefore related to impaired angiogenesis in diabetes. Transfection of an miR-320 inhibitor may be a therapeutic approach for the treatment of impaired angiogenesis in diabetes.

Reproductive health risks and HIV infection vulnerability of hostesses in metropolitan areas, China: a qualitative study

In this paper, we describe sex-related health risks among hostesses in two metropolises in China based on data obtained from in-depth interviews. The data show that hostesses, many engaging in commercial sex, are vulnerable to HIV infection, unwanted pregnancies and reproductive tract infections. Nevertheless, many obstacles still are present that hinder them from engaging in safe sex. The findings from our study illustrate the need for targeted interventions in order to improve reproductive health and promote safe sex among this group.

Characterization of viscoelastic properties of normal and osteoarthritic chondrocytes in experimental rabbit model

The goal of this study was to characterize the changes of the viscoelastic properties of rabbit chondrocytes from normal and osteoarthritic cartilage. All samples were harvested from rabbit articular cartilage with the same age, sex, body weight, breed and osteoarthritic degree. Anterior cruciate ligament transection was utilized to induce rabbit osteoarthritic model. Micropipette aspiration technique coupled with a viscoelastic model was used to characterize viscoelastic properties of rabbit chondrocytes. The present results indicate that the viscoelastic behaviors of osteoarthritic chondrocytes have decreased during the progress of osteoarthritis and exhibited a significantly lower equilibrium modulus, instantaneous modulus and apparent viscosity (E( proportional, variant)=0.39+/-0.14 kPa, E(0)=0.68+/-0.27 kPa, mu=0.39+/-0.14 kPa.s, n=67) compared with normal chondrocytes (E( proportional, variant)=0.55+/-0.11 kPa, E(0)=0.98+/-0.14 kPa, mu=6.36+/-1.12 kPa.s, n=52) (p<0.0001). These findings may be relevant for chondrocyte-based cartilage tissue engineering.

E-cadherin upregulation as a therapeutic goal in cancer treatment

We review the role of E-cadherin in cancer progression, and its therapeutic restoration as a strategy to suppress metastasis. We subsequently discuss E-cadherin upregulating drugs, proposing a schema for restoring E-cadherin by targeting its epigenetic and transcriptional regulators. These pathways will likely provide significant future treatment breakthroughs against cancer metastasis.

Functional significance of VEGF-a in human ovarian carcinoma: role in vasculogenic mimicry

Ovarian cancer is a silent killer, and shows early extensive tumor invasion and peritoneal metastasis. The microcirculation of most tumors includes cooperation of pre-existing vessels, intussusceptive microvascular growth, postnatal vasculogenesis, glomeruloid angiogenesis and vasculogenic mimicry (VM). VM is critical for a tumor blood supply and is asscociated with aggressive features and metastasis. Our studies highlight the plasticity of aggressive human ovarian carcinoma cells and call into question the underlying significance of their ability to form VM in vitro induced by VEGF-a. These studies also show their clinicalpathological features of the cancers with human Paraffin-embedded tumor tissue samples. Results show that the process: VEGF-a-->EphA2-->MMPs-->VM is the main pathway for VM formation and VEGF-a appears to play an important role in the formation of VM based on our in vitro assays and clinical immunohistochemical analyses. VM-targeting strategies for ovarian cancer include anti-VEGF-a treatment, knocking down the EphA2 gene and using antibodies against human MMPs if the tumor is VM positive. This strategy may be of significant value in laying the foundation for a more explicit anti-tumor angiogenesis therapy.

Analytical methods for the determination of zeranol residues in animal products: A review

Analytical methods for zeranol residues are reviewed. Zeranol was a widely used as an anabolic promoter, and it could give rise to very low residues in the edible tissues of food animals. Zeranol was officially banned in Europe due to safety concerns because of its potential carcinogenic and endocrine-disrupting biological activity. A few analytical methods for determination of zeranol are reported in the literature and most of the methods such as thin-layer chromatography (TLC), gas chromatography-mass spectrometry (GC/MS), high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC/MS) and immunoassay are reviewed in this paper. Specific aspects of analysing zeranol such as sample selection, sample handling, method selection and chromatographic conditions are discussed. The instrumental methods such as LC/MS and GC/MS provide sensitive and specific techniques, but are very laborious and expensive. These methods are suitable for confirmation but not for screening of large numbers of samples. A rapid, sensitive and specific assay is needed to detect positive samples in routine analysis, and immunoassay offers practical advantages over the conventional instrumental methods in rapid analysis of zeranol residues. Immunochemical methods such as enzyme-linked immunoabsorbant assay (ELISA) are simple, rapid and cost-effective, with adequate sensitivity and specificity to detect small molecules. This review can be considered as a basis for further research aimed at identifying the most efficient approaches for the analysis of zeranol.

X-chromosome linked inhibitor of apoptosis protein inhibits muscle proteolysis in insulin-deficient mice

Loss of muscle protein is a serious complication of catabolic diseases and contributes substantially to patients' morbidity and mortality. This muscle loss is mediated largely by the activation of the ubiquitin-proteasome system; however, caspase-3 catalyzes an initial step in this process by cleaving actomyosin into small protein fragments that are rapidly degraded by the proteasome-dependent proteolytic pathway. We hypothesized that X-chromosome linked inhibitor of apoptosis protein (XIAP), an endogenous caspase-3 inhibitor, would block this first step in the cleavage of actomyosin that would make XIAP a candidate for treating muscle wasting. To determine if XIAP could attenuate muscle protein degradation, we used a recombinant lentivirus (Len-XIAP) encoding the full-length human XIAP cDNA to express XIAP in vivo. In muscle of streptozotocin-treated insulin-deficient mice, total muscle protein degradation, caspase-3 activity, and myofibril destruction were increased while XIAP was decreased. Overexpression of XIAP in these mice attenuated the excessive muscle protein degradation. Increased proteasome activity, caspase-3 activity and myofibril protein breakdown were all reduced. The ability of XIAP to prevent the loss of muscle protein suggests that XIAP could be a therapeutic reagent for muscle atrophy in catabolic diseases.

Wavelength-Sensitive Photocatalytic Degradation of Methyl Orange in Aqueous Suspension over Iron(III)-doped TiO2Nanopowders under UV and Visible Light Irradiation

Well-crystallized iron(III)-doped TiO2 nanopowders with controlled Fe3+ doping concentration and uniform dopant distribution, have been synthesized with plasma oxidative pyrolysis. The photocatalytic reactivity of the synthesized TiO2 nanopowders with a mean particle size of 50-70 nm was quantified in terms of the degradation rates of methyl orange (MO) in aqueous TiO2 suspension under UV (mainly 365 and 316 nm) and visible light irradiation (mainly 405 and 436 nm). The photodecomposition of MO over TiO2 nanopowders followed a distinct two-stage pseudo first order kinetics. Interestingly, the photocatalytic reactivity depends not only on the iron doping concentration but also on the wavelength of the irradiating light. Under UV irradiation, nominally undoped TiO2 had much higher reactivity than Fe3+ -doped TiO2, suggesting that Fe3+ doping (> 0.05 at. %) in TiO2 with a mean particle size of approximately 60 nm was detrimental to the photocatalytic decomposition of methyl orange. Whereas, under visible light irradiation, the Fe3+ -doped TiO2 with an intermediate iron doping concentration of approximately 1 at. % had the highest photocatalytic reactivity due to the narrowing of band gap so that it could effectively absorb the light with longer wavelength. A strategy for improving the photocatalytic reactivity of Fe3+ -doped TiO2 used in the visible light region is also proposed.

Antisense oligonucleotides targeted against asialoglycoprotein receptor 1 block human hepatitis B virus replication

Chronic hepatitis B virus (HBV) infection is a major worldwide public health problem. Better therapeutics and treatment strategies are urgently needed because of ineffective clinical treatment. Our previous study showed that asialoglycoprotein receptor 1 (ASGPR1) was upregulated by HBV but downregulated by lamivudine in HepG2.2.15 cells. It has also been reported that ASGPR is a candidate receptor for HBV attachment to hepatocytes. Therefore, as a major subunit of ASGPR, ASGPR1, might be a potential target for anti-HBV drugs. To validate this hypothesis, antisense oligonucleiotides (ASODNs) were used to downregulate ASGPR1 level in HepG2.2.15 cells. By using the MFOLD web server and BLAST searches, five ASODNs theoretically targeting ASGPR1 were selected. After 72 h post-transfection, HBV-DNA level in cell medium were examined by real-time polymerase chain reaction (PCR). Hepatitis B surface antigen (HBsAg) and Hepatitis B e antigen (HBeAg) were detected using enzyme-linked immunosorbent assay (ELISA). ASGPR1 mRNA and protein level were measured by semi-quantitative reverse transcriptase (RT)-PCR and Western blot analysis respectively. The results showed that ASODN2 significantly downregulated ASGPR1 level. It also reduced HBV-DNA, HBsAg and HBeAg level in cell medium as observed with lamivudine. In contrast, the sense sequence and scrambled sequence of ASODN2 had no effect on ASGPR1 and HBV markers in HepG2.2.15 cells. This indicated that ASODN2 could specifically reduce HBV replication in vitro. Additionally, cell proliferation and apoptosis assay suggested that downregulation of ASGPR1 did not affect cell viability. We, therefore, proposed that ASODNs targeted against ASGPR1 could block HBV replication without the influence of other changes, and ASGPR1 could be targeted for anti-HBV drug development.