Stable Permanently Hydrophilic Protein-Resistant Thin-Film Coatings on Poly(dimethylsiloxane) Substrates by Electrostatic Self-Assembly and Chemical Cross-Linking

Poly(dimethylsiloxane) (PDMS) is a biomaterial that presents serious surface instability characterized by hydrophobicity recovery. Permanently hydrophilic PDMS surfaces were created using electrostatic self-assembly of polyethyleneimine and poly(acrylic acid) on top of a hydrolyzed poly(styrene-alt-maleic anhydride) base layer adsorbed on PDMS. Cross-linking of the polyelectrolyte multilayers (PEMS) by carbodiimide coupling and covalent attachment of poly(ethylene glycol) (PEG) chains to the PEMS produced stable, hydrophilic, protein-resistant coatings, which resisted hydrophobicity recovery in air. Attenuated total reflection Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the thin films had excellent chemical stability and resisted hydrophobicity recovery in air over 77 days of measurement. The spectra also showed a dense coverage for PEG dialdehyde and excellent resistance to protein adsorption from undiluted rat serum. Atomic force microscopy revealed dense coverage with PEG dialdehyde and PEG diamine. Contact angle measurements showed that all films were hydrophilic and that the PEG dialdehyde-topped thin film had a virtually constant contact angle (approximately 20 degrees ) over the five months of the study. Electrokinetic analysis of the coatings in microchannels always exposed to air also gave good protein separation and constant electroosmotic flow during the five months that the measurements were done. We expect that the stable, hydrophilic, protein-resistant thin-film coatings will be useful for many applications that require long-term surface stability.

Chip-based microfluidic devices coupled with electrospray ionization-mass spectrometry

We present the current status of the development of microfluidic devices fabricated on different substrates for coupling with electrospray ionization-mass spectrometry (ESI-MS). Until now, much success has been gained in fabricating the ESI chips, which show better performances due to miniaturization when compared with traditional methods. Integration of multiple steps for sample preparation and ESI sample introduction, however, remains a great challenge. This review covers the main technical development of electrospray device that were published from 1997 to 2004. This article does not attempt to be exclusive. Instead, it focuses on the publications that illustrated the breath of the development and applications of microchip devices for MS-based analysis.

Identification of novel vaccine candidates against Acinetobacter baumannii using reverse vaccinology

Acinetobacter baumannii (Ab) is a global emerging bacterium causing nosocomial infections such as pneumonia, meningitis, bacteremia and soft tissue infections especially in intensive care units. Since Ab is resistant to almost all conventional antibiotics, it is now one of the 6 top-priorities of the dangerous microorganisms listed by the Infectious Disease Society of America. The development of vaccine is one of the most promising and cost-effective strategies to prevent infections. In this study, we identified potential protective vaccine candidates using reverse vaccinology. We have analyzed 14 on-line available Ab genome sequences and found 2752 homologous core genes. Using information obtained from immuno-proteomic experiments, published proteomic information and the bioinformatics PSORTb v3.0 software to predict the location of extracellular and/or outer membrane proteins, 77 genes were identified and selected for further studies. After excluding those antigens have been used as vaccine candidates reported by the in silico search-engines of PubMed and Google Scholar, 13 proteins could potentially be vaccine candidates. We have selected and cloned the genes of 3 antigens that were further expressed and purified. These antigens were found to be highly immunogenic and conferred partial protection (60%) in a pneumonia animal model. The strategy described in the present study incorporates the advantages of reverse vaccinology, bioinformatics and immuno-proteomic platform technologies and is easy to perform to identify novel immunogens for multi-component vaccines development.

Gender differences in tobacco use in Africa, Asia, the Pacific, and Latin America

This paper reviews historical, anthropological and contemporary survey data concerning gender differences in tobacco use in Africa, Asia, the Pacific, and Latin America. In many cultural groups in these regions, tobacco use has been substantially more common among men than among women. In some groups, tobacco use has been about equally common for both sexes. No evidence was found of any group in which tobacco use has been substantially more common among women. The widespread pattern of greater tobacco use by men appears to be linked to general features of sex roles. For example, men have often had greater social power than women, and this has been expressed in greater restrictions on women's behavior, including social prohibitions against women's smoking. These social prohibitions against women's smoking have strongly inhibited women's tobacco use and thus have been a major cause of gender differences in tobacco use. Gender differences in tobacco use have varied in magnitude, depending on the type of tobacco use and the particular cultural group, age group and historical period considered. Causes of the variation in gender differences in tobacco use include variation in women's status and variation in the social significance and benefits attributed to particular types of tobacco use in different cultures. Contact with Western cultures appears to have increased or decreased gender differences in smoking, depending on the specific circumstances. The patterns of gender differences in tobacco use in non-Western societies are similar in many ways to the patterns observed in Western societies, but there are several important differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term affinity modification on poly(dimethylsiloxane) substrate and its application for ELISA analysis

Poly(dimethylsiloxane) (PDMS) possesses many advantages, such as biocompatibility and high oxygen permeability, which makes it an attractive material for fabricating biodevices. Creating an affinity surface with long-term stability and reactivity for biomolecular interactions on a PDMS substrate, however, is difficult due to its inherent hydrophobicity. In this study, an affinity surface on a PDMS substrate with long-term hydrophilicity and affinity reactivity is reported. This modification is composed of two parts. The bottom part is made of polyelectrolyte multilayers and is capable of providing long-term hydrophilic stability. The top part consists of three protein layers, bovine serum albumin (BSA), anti-BSA, and protein G, and offers an affinity surface for antibody binding and, more importantly, provides favorable orientation and minimum nonspecific binding. The chemical modification for the different stages was monitored by atomic force microscopy (AFM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR), and contact angle and fluorescence measurements. A long-term PDMS immunodevice (LPID) based on polyelectrolyte multilayers and protein layers was fabricated and applied to the detection of transforming growth factor beta (TGF-beta) protein in mouse serum by the enzyme-linked immunosorbent assay (ELISA) method. Results show that a linear calibration curve was obtained in the concentration range from 500 to 15.125 pg/mL, and the relative standard deviation was less than 3%. Also, the amount of TGF-beta spiked in mouse serum was precisely determined. Results indicate that the modified surface was hydrophilic and reactive to biospecies up to more than 7 days in its dry form. Moreover, the blocking reagent used to reduce nonspecific binding was found to be not necessary for the LPID. Thus, the reported method is expected to hold a great potential for fabricating PDMS-based affinity devices such as protein chips.

A disposable poly(methylmethacrylate)-based microfluidic module for protein identification by nanoelectrospray ionization-tandem mass spectrometry

The design, fabrication, and analytical use of a poly(methylmethacrylate) (PMMA)-based microfluidic module for nanoelectrospray ionization-tandem mass spectrometry (nano-ESI-MS/MS) were described. The microfluidic module can be mass-produced at low costs and used as a disposable device to generate nano-ESI-MS/MS signals for protein identification from low amounts of protein samples. Compared with commercially available nanospray capillary tips, the module gave comparable signal quality and also offered advantages in convenience and easiness of operation, permitting repeated usage, and disposability.

Plastic microchip electrophoresis for genetic screening: The analysis of polymerase chain reactions products of fragile X (CGG)n alleles

Clinical screening of abnormal chromosomes associated with fragile X syndrome (FXS) demands a high-throughput method including DNA sizing and detection of the amplified products. This study is to explore the use of polymer microchip electrophoresis for the analysis of polymerase chain reaction (PCR) products of fragile X (CGG)n alleles to facilitate a fast exclusion test of FXS. The sequences flanking the CGG-repeat of FMR1 gene was amplified by betaine-PCR and the amplified products were desalted and then analyzed by microchips which were fabricated on poly(methyl methacrylate) (PMMA) substrate. The PCR bands with more than six CGG-repeats in difference could be clearly distinguished in less than 3 min by microchip electrophoresis with a separation length of 6 cm. It was found that the signal was greatly enhanced with the use of both covalent (Cy5) and intercalating dye (TORRO-3), which has never been demonstrated before. We tested the method by reanalysis of twelve samples from males and six samples from females. For female samples with less than six repeat differences, Southern blotting method was performed to confirm or exclude the findings from microchips. It was found that the test results from all male and female samples show a 100% correlation between the microchip electrophoresis and the existing methods.

Functionalized 3D-hydrogel plugs covalently patterned inside hydrophilic poly(dimethylsiloxane) microchannels for flow-through immunoassays

Integration of a hydrogel and polydimethylsiloxane (PDMS)-based microfluidic device can greatly reduce the cost of developing channel-based devices. However, there are technical difficulties including the hydrophobic and inert surface properties associated with PDMS as well as back pressure and fragile material associated with the use of hydrogel in microchannels. In this study, a strategy to covalently photopattern 3-D hydrogel plugs with functionalized protein G inside microfluidic channels on a hydrophilic PDMS substrate coated with polyelectrolyte multilayers (PEMS) is presented. In this process, a UV-light microscope is applied to initiate the protein G-poly(acryl amide) copolymerization from the bulk substrate to solution areas via the deeply implanted photoinitiator (PI), resulting in sturdy 3D plugs covalently bonded to the upper and lower channel wall, while leaving open spaces in the channel width for the fluid to flow through. In addition, the long-term hydrophilicity and low nonspecific binding property associated with PEMS surface can be conserved for the nonpatterned area, leading to hydrogel plugs in extremely hydrophilic and permeable environment in a restricted channel space for bubble-free fluid transport and affinity interaction. By immobilization of well-oriented antibodies via protein G on the hydrogel plugs in the channel, estrogen receptor alpha (ERalpha) is demonstrated to be captured quantitatively with high loading capacity and high specificity.

Poly(dimethylsiloxane)-based microfluidic device with electrospray ionization-mass spectrometry interface for protein identification

An easy method to fabricate poly(dimethylsiloxane) (PDMS)-based microfluidic chips for protein identification by tandem mass spectrometry is presented. This microchip has typical electrophoretic microchannels, a flow-through sampling inlet, and a sheathless nanoelectrospray ionization (ESI) interface. The surface of the microchannel was modified with 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and the generated electroosmotic flow under acidic buffer condition used for the separation was found to be more stable compared to that generated by the microchannel without modification. The feasibility of the device for flow-through sampling, separation, and ESI-MS/MS analysis was demonstrated by the analysis of a standard mixture composed of three tryptic peptides. Results show that four peaks corresponding to three peptide standards and acetylated products of the standard peptide were well resolved and the deduced sequences were consistent with those expected. Furthermore, the compatibility of this device with other miniaturized devices to integrate the whole process was also explored by connecting a miniaturized enzymatic digestion cartridge and a desalting cartridge in series to the sampling inlet of the microchip for the identification of a model protein, beta-casein.

Effect of dietary vitamin E on antioxidant status and antioxidant enzyme activities in Sprague-Dawley rats

The effect of dietary vitamin E on plasma, red blood cells (RBC), hepatic antioxidant status, and antioxidant enzyme activities was investigated. Three groups of six Sprague-Dawley rats were fed 0, 100, or 1,500 ppm vitamin E for eight weeks. Plasma alpha-tocopherol level was increased significantly by increasing dietary vitamin E (p < 0.05). Plasma lipid peroxidation (thiobarbituric acid-reactive substances) stimulation by 1 mM t-butyl hydroperoxide was correlated with dietary vitamin E level and was significantly greater in rats fed no vitamin E than in rats fed 100 or 1,500 ppm vitamin E (p < 0.05). RBC reduced glutathione (GSH) level was positively correlated with dietary vitamin E and was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed 0 or 100 ppm vitamin E (p < 0.05). RBC oxidized glutathione was negatively correlated with dietary vitamin E. GSH redox status was expressed as the GSH-to-total GSH ratio; the ratio was also positively correlated with dietary vitamin E and was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed no vitamin E (p < 0.05). For antioxidant enzymes, superoxide dismutase activity in hepatic cytosolic fraction was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed 100 ppm vitamin E. Hepatic GSH reductase activity was significantly greater in rats fed 100 ppm vitamin E than in rats fed no vitamin E (p < 0.05). Dietary vitamin E had no effect on plasma vitamin C and protein thiol levels. In the systems studied, results indicated that dietary vitamin E selectively influences plasma vitamin E level, RBC GSH status, and hepatic cytosolic superoxide dismutase and GSH reductase activities.

A biphasic response pattern of lipid metabolomics in the stage progression of hepatitis B virus X tumorigenesis

Metabolic syndrome has closely linked to the development of human hepatocellular carcinoma (HCC). By using the hepatitis B virus (HBV) X (HBx) transgenic mouse model, we studied the dynamic evolution of serum and liver profiles of lipids and global cDNA expression at different stages of HBx tumorigenesis. We observed that the lipid (triglycerides, cholesterol, and fatty acids) profiles revealed a biphasic response pattern during the progression of HBx tumorigenesis: a small peak at early phase and a large peak or terminal switch at the tumor phase. By analyzing cDNA microarray data, the early peak correlated to the oxidative stress and pro-inflammatory response, which then resolved at the middle phase and were followed by the terminal metabolic switch in the tumor tissues. Five lipid metabolism-related genes, the arachidonate 5-lipoxygenase, lipoprotein lipase, fatty acid binding protein 4, 1-acylglycerol-3-phosphate O-acyltransferase 9, and apolipoprotein A-IV were identified to be significantly activated in HBx transgenic HCCs and further validated in human HBV-related HCCs. Inhibition of these lipid genes could reverse the effect of HBx on lipid biosynthesis and suppress HBx-induced cell proliferation in vitro. Our results support the concept that metabolic syndrome plays an important role in HBV tumorigenesis. The dysregulation of lipid metabolic genes may predict the disease progression to HCC in chronic hepatitis B patients.

Evaluation of disulfide scrambling during the enzymatic digestion of bevacizumab at various pH values using mass spectrometry

Disulfide linkages play an important role in protein stability and activity. Thus, it is critical to characterize disulfide bonds to ensure the quality and function of protein pharmaceuticals. There are, however, problems associated with maintaining disulfide linkages in the conventional procedures that are used to digest a protein. In order to preserve enzyme activity during the digestion of a protein, it is commonly carried out at neutral to basic environment which increases the possibilities of disulfide bond scrambling. However, it is not easy to differentiate whether the scrambled disulfide linkages are initiated by the sample itself or whether they are induced during the protease digestion process. In this study, the optimum pH for minimizing disulfide bond rearrangements during the digestion process was determined. Three sets of proteases, trypsin plus Glu-C, Lys-C and thermolysin were used, followed by dimethyl labeling and mass spectrometry for a bevacizumab (Avastin) disulfide linkage analysis. No disulfide linkage scrambling was detected at pH6 when Lys-C or trypsin plus Glu-C were used as enzymes. When thermolysin was applied, some scrambled disulfide bonds were identified at pH5, 6 and 7. Nevertheless, there was less disulfide bond scrambling at a lower pH. All correct disulfide bonds on bevacizumab could be identified using this approach. The results demonstrated that by choosing the proper enzymes, using a lower pH environment for the digestion could reduce the degree of artifact disulfide scrambling.

The role of a nuclear protein, histone H1, on signalling pathways for the maturation of dendritic cells

We have demonstrated previously that liver allograft tolerance is associated with the immunosuppressive activity of anti-histone H1 autoreactive antibodies induced in the serum of liver transplantation. Furthermore, we and others have shown that nuclear proteins such as histone H1 and high mobility group box 1 play an important role in maturation of dendritic cells (DCs), although the precise mechanisms are still unknown. In the present study, we focus upon the significance of histone H1 on DCs in terms of the intracellular signalling pathway of DCs. Our immunostaining and immunoblot studies demonstrated that histone H1 was detected in cytoplasm and culture supernatants upon the activation of DCs. Histone H1 blockage by anti-histone H1 antibody down-regulated the intracellular activation of mitogen-activated protein kinases (MAPKs) (p38) and IkappaBalpha of DCs, and inhibited DC activity in the proliferation of CD4+ T cells. On the other hand, the addition of histone H1 without endotoxin stimulation up-regulated major histocompatibility complex class II, the CD80 and CD86 surface markers of DCs and the activation of MAPKs (p38 and extracellular-regulated kinase 1/2) and IkappaBalpha. These results suggest that the translocation of histone H1 from nuclei to cytoplasm and the release of their own histone H1 are necessary for the maturation of DCs and the activation for T lymphocytes.

Recent advances in pharmacokinetic applications of capillary electrophoresis

This article reviews recent capillary electrophoresis (CE)-based assays which were published for pharmacokinetic studies. Both the advantages and disadvantages of these CE-based assays are discussed based on their feasibility and the significance towards the better understanding of pharmacokinetics. In addition, as a future outlook, novel assays such as immunoaffinity CE and chip-based CE for analyzing drugs in biological fluids are summarized in view of their potential for pharmacokinetic applications.

A Rapid and International Applicable Diagnostic Device for Cobra (Genus Naja) Snakebites

Cobra snakes (genus Naja) are some of the most dangerous snake species in Asia and Africa, as their bites cause severe life-threatening respiratory failure and local tissue destruction, especially in the case of late diagnosis. The differential diagnosis of snakebite envenomation still mainly relies upon symptomatology, the patient’s description, and the experience of physicians. We have designed a rapid test, immunochromatographic test of cobra (ICT-Cobra), which obtained fair results in improving the diagnosis and treatment of Naja (N.) atra snakebites in Taiwan. In this study, we further investigated the feasibility of applying the kit for the detection of other cobra venoms based on the potential interspecies similarity. We firstly demonstrated the cross-reactivity between eight venoms of medically important cobra species and the rabbit anti-N. atra IgG that was used in ICT-Cobra by Western blotting and sandwich enzyme-linked immunosorbent assay. Then, ICT-Cobra was used to detect various concentrations of the eight venoms to elucidate its performance. Noticeable correlations between the cross-reactivity of venoms from genus Naja snakes and existing geographical characteristics were found. ICT-Cobra could detect venoms from other Asian cobras with variable detection limits comparable to those observed for N. atra, but the kit was less successful in the detection of venom from African cobras. The similar but slightly different venom components and the interaction between venom and rabbit anti-N. atra IgG led to variations in the detection limits. The transcontinental usage of ICT-Cobra might be possible due to the cross-reactivity of antibodies and similarities among the larger-sized proteins. This study showed that the close immunological relationships in the genus Naja could be used to develop a venom detection kit for the diagnosis of cobra envenomation in both Asian and African regions. Additional clinical studies and technical adjustments are still needed to improve the efficacy and broadening the application of ICT-Cobra in the future.

Development of a Broad-Spectrum Antiserum against Cobra Venoms Using Recombinant Three-Finger Toxins

Three-finger toxins (3FTXs) are the most clinically relevant components in cobra (genus Naja) venoms. Administration of the antivenom is the recommended treatment for the snakebite envenomings, while the efficacy to cross-neutralize the different cobra species is typically limited, which is presumably due to intra-specific variation of the 3FTXs composition in cobra venoms. Targeting the clinically relevant venom components has been considered as an important factor for novel antivenom design. Here, we used the recombinant type of long-chain α-neurotoxins (P01391), short-chain α-neurotoxins (P60770), and cardiotoxin A3 (P60301) to generate a new immunogen formulation and investigated the potency of the resulting antiserum against the venom lethality of three medially important cobras in Asia, including the Thai monocled cobra (Naja kaouthia), the Taiwan cobra (Naja atra), and the Thai spitting cobra (Naja Siamensis) snake species. With the fusion of protein disulfide isomerase and the low-temperature settings, the correct disulfide bonds were built on these recombinant 3FTXs (r3FTXs), which were confirmed by the circular dichroism spectra and tandem mass spectrometry. Immunization with r3FTX was able to induce the specific antibody response to the native 3FTXs in cobra venoms. Furthermore, the horse and rabbit antiserum raised by the r3FTX mixture is able to neutralize the venom lethality of the selected three medically important cobras. Thus, the study demonstrated that the r3FTXs are potential immunogens in the development of novel antivenom with broad neutralization activity for the therapeutic treatment of victims involving cobra snakes in countries.

Effect of vitamin E on rat hepatic cytochrome P-450 activity

Hepatic cytochrome P-450 activity has been shown to be affected by various dietary factors including vitamin E. However, reports of the effect of dietary vitamin E on cytochrome P-450 activity have been inconsistent. The aim of the present study was to investigate the influence of dietary vitamin E on rat hepatic cytochrome P-450 activity. Three groups of six male weanling Sprague-Dawley rats were fed semipurified diets containing 0, 100, or 1,500 ppm vitamin E for eight weeks. Vitamin E was given in the form of alpha-tocopheryl acetate. Dietary vitamin E significantly affected liver vitamin E content (p < 0.05) but had no effect on rat hepatic total P-450 content, N-nitrosodimethylamine demethylase, and NADPH-cytochrome-P-450 reductase activities. Hepatic pentoxyresorufin O-dealkylase and glutathione S-transferase activities were significantly greater in rats fed 100 and 1,500 ppm vitamin E than in rats fed no vitamin E (p < 0.05). Dietary vitamin E induced changes in hepatic phospholipid fatty acid composition. Hepatic phospholipid linoleate was significantly greater in rats fed 0 and 1,500 ppm vitamin E than in rats fed 100 ppm vitamin E (p < 0.05). Hepatic phospholipid eicosapentaenoate was increased significantly by dietary vitamin E (p < 0.05). Hepatic thiobarbituric acid-reactive substance was significantly greater in rats fed no vitamin E than in rats fed 100 and 1,500 ppm vitamin E (p < 0.05). The results suggest that vitamin E may influence cytochrome P-450 IIB1 enzyme activity and may affect hepatic phospholipid fatty acid composition.

Development of high-growth influenza H7N9 prepandemic candidate vaccine viruses in suspension MDCK cells

BACKGROUND

Influenza vaccine manufacturers traditionally use egg-derived candidate vaccine viruses (CVVs) to produce high-yield influenza viruses for seasonal or pandemic vaccines; however, these egg-derived CVVs need an adaptation process for the virus to grow in mammalian cells. The low yields of cell-based manufacturing systems using egg-derived CVVs remain an unsolved issue. This study aimed to develop high-growth cell-derived CVVs for MDCK cell-based vaccine manufacturing platforms.

METHODS

Four H7N9 CVVs were generated in characterized Vero and adherent MDCK (aMDCK) cells. Furthermore, reassortant viruses were amplified in adherent MDCK (aMDCK) cells with certification, and their growth characteristics were detected in aMDCK cells and new suspension MDCK (sMDCK) cells. Finally, the plaque-forming ability, biosafety, and immunogenicity of H7N9 reassortant viruses were evaluated.

RESULTS

The HA titers of these CVVs produced in proprietary suspension MDCK (sMDCK) cells and chicken embryos were 2- to 8-fold higher than those in aMDCK cells. All H7N9 CVVs showed attenuated characteristics by trypsin-dependent plaque assay and chicken embryo lethality test. The alum-adjuvanted NHRI-RG5 (derived from the fifth wave H7N9 virus A/Guangdong/SP440/2017) vaccine had the highest immunogenicity and cross-reactivity among the four H7N9 CVVs. Finally, we found that AddaVax adjuvant improved the cross-reactivity of low pathogenic H7N9 virus against highly pathogenic H7N9 viruses.

CONCLUSIONS

Our study indicates that cell-derived H7N9 CVVs possessed high growth rate in new sMDCK cells and low pathogenicity in chicken embryo, and that CVVs generated by this platform are also suitable for both cell- and egg-based prepandemic vaccine production.

The stability and immunogenicity of inactivated MDCK cell-derived influenza H7N9 viruses

In recent years, cell-based influenza vaccines have gained a great interest over the egg-based vaccines. Several inactivated H7N9 vaccines have been evaluated in clinical trials, including whole-virion vaccines, split vaccines and subunit vaccines. Recently, we developed a new suspension MDCK (sMDCK) cell line for influenza viruses production. However, the properties of purified antigen from sMDCK cells remain unclear. In this study, the stability of influenza H7N9 vaccine bulk derived from sMDCK cells was investigated, and the data were compared with the vaccine antigen derived from our characterized adhesion MDCK (aMDCK) cells in serum-free medium. The influenza H7N9 bulks derived from sMDCK and aMDCK cells were stored at 2-8 °C for different periods of time, and a number of parameters selected to monitor the H7N9 vaccine antigen stability were evaluated at each interval (1, 3 and 12 months). The monitored parameters included virus morphology, hemagglutinin (HA) activity, HA concentration, antigenicity, and immunogenicity. The sMDCK-derived H7N9 bulk showed similar morphology to that of the aMDCK-derived H7N9 bulk, and there were no obvious changes after the extended storage periods. Furthermore, the HA titer, HA concentration, and antigenicity of sMDCK-derived H7N9 bulk were stable after 28 months of storage. Finally, the results of hemagglutination inhibition and neutralization tests showed that sMDCK- and aMDCK-derived H7N9 vaccines had comparable immunogenicity. These results indicated that sMDCK-derived H7N9 bulk has good stability compared to that of aMDCK-derived H7N9 bulk. Thus, the newly developed suspension MDCK cell line shows a great alternative for manufacturing cell-based influenza vaccines.

alpha-Tocopherol acetate supplementation enhances rat hepatic cytochrome PROD activity in the presence of phenobarbital induction

Hepatic cytochrome P-450 enzymes play important roles in bioactivation of chemical carcinogens, biotransformation of many endogenous compounds, and detoxification of numerous xenobiotics. These enzyme activities have been shown to be regulated by various dietary factors. In our previous study, hepatic cytochrome pentoxyresorufin O-dealkylase (PROD) activity was decreased in rats fed an alpha-tocopherol acetate-deficient diet compared with rats fed alpha-tocopherol acetate-adequate or -supplemented diets. The objective of the present study was to investigate whether the modulatory effect of dietary alpha-tocopherol acetate on hepatic cytochrome PROD activity is influenced by the presence of phenobarbital. Weanling male Sprague-Dawley rats were fed the AIN-76 diet for four days, fasted for two days, then fed semipurified diets that were alpha-tocopherol acetate deficient, adequate, or supplemented with 5 and 15 g/kg alpha-tocopherol acetate for four days. Liver and plasma alpha-tocopherol concentrations were dose dependently regulated by dietary alpha-tocopherol acetate level. Inhibition of lipid peroxidation by dietary alpha-tocopherol acetate was dose dependent. Hepatic total cytochrome P-450 content was significantly greater in rats fed diets supplemented with 5 and 15 g/kg alpha-tocopherol acetate than in rats fed an alpha-tocopherol-adequate diet (p < 0.05). Hepatic cytochrome PROD activity was significantly greater in rats fed diets supplemented with 5 and 15 g/kg alpha-tocopherol acetate than in rats fed alpha-tocopherol acetate-deficient and -adequate diets (p < 0.05). These results suggest that, in the presence of phenobarbital, dietary alpha-tocopherol acetate efficiently affects tissue alpha-tocopherol levels and inhibits lipid peroxidation and that diets supplemented with 5 or 15 g/kg alpha-tocopherol acetate enhance hepatic cytochrome PROD activity compared with alpha-tocopherol acetate-deficient or -adequate diets.

Pharmacokinetic applications of capillary electrophoresis: A review on recent progress

This article covers recent publications from 2003 to 2005 on the subject of pharmacokinetic applications of CE. Many analytical methods were validated and more importantly, they were shown to have sufficient sensitivities to access pharmacokinetic data on different models. Because of unique advantages, such as simplified sample preparation methods, small sample amount required, high separation power, and speedy analysis, CE-based assays were found to gain popularity not only as a second method but also as a major method for many pharmacokinetic studies.

Depletion of regulatory T-cells leads to moderate B-cell antigenicity in respiratory syncytial virus infection

OBJECTIVES

The regulation of the immunopathology of respiratory syncytial virus (RSV) by regulatory T-cells (CD4(+)CD25(+)Foxp3(+); Tregs) is not understood.

METHODS

To deduce the same, Tregs were depleted in BALB/c mice by injecting anti-CD25 antibody followed by RSV infection (anti-CD25-RSV mice).

RESULTS

In this model, a decrease in anti-fusion (F) antibody and neutralizing activity, and an increase in anti-nucleocapsid (N) antibody in serum, were seen. Decreased antibody-dependent cell-mediated cytotoxicity (ADCC) activity, increased IgG2a, and an influx of activated CD8(+) T-cells into the lungs were also observed. Co-culture of splenic CD45RA(+) B-cells from RSV-infected normal mice with CD4(+) cells isolated from anti-CD25-RSV mice (B/CD4) increased anti-F antibody secretion. The inclusion of CD25(+) Tregs isolated from isotype Ig-RSV mice into the B/CD4 co-culture substantially enhanced the frequency of anti-F antibody production. However, the same effect was not seen in the co-culture of CD45RA(+) B-cells with dendritic cells (DCs) (B/DCs) or CD8(+) cells (B/CD8) that were obtained from anti-CD25-RSV mice. The transfer of enriched B-cells from anti-CD25-RSV mice into RSV-infected SCID mice increased severe lung inflammation associated with the increased viral load and eosinophil number.

CONCLUSIONS

These results indicate that Tregs modulate B-cell activity, particularly in producing F-specific neutralizing antibodies, to regulate RSV-mediated exacerbated diseases.