Flexible 3D carbon nanotubes cuff electrodes as a peripheral nerve interface

The cuff electrode provides a stable interface with peripheral nerves, which has been widely used in basic research and clinical practice. Currently, the cuff electrodes are limited by the planar processing of microfabrication. This paper presents a novel cuff electrode using high-aspect ratio carbon nanotubes (CNTs) integrated on a flexible biocompatible parylene. The microfabrication process unites the high quality vertical CNTs grown at high temperature with the heat sensitive parylene substrate in a highly controllable manner. The fabricated cuff electrodes have been utilized for extracellular nerve stimulation in rats. The experimental results demonstrate the proposed CNT electrode has a better performance than Pt electrode in nerve stimulation. Moreover, the effect of electrode position and stimulation frequency is demonstrated in this paper. This preliminary data indicates that flexible 3D CNTs cuff electrode provides an excellent platform for functional electrical stimulation.

Diving–floating locomotion induced by capturing and manipulating bubbles in an aqueous environment

A superaerophilic surface achieves capturing and manipulating bubbles to induce the diving-floating locomotion.

A novel fabrication method of carbon electrodes using 3D printing and chemical modification process

Three-dimensional (3D) printing is an emerging technique in the field of biomedical engineering and electronics. This paper presents a novel biofabrication method of implantable carbon electrodes with several advantages including fast prototyping, patient-specific and miniaturization without expensive cleanroom. The method combines stereolithography in additive manufacturing and chemical modification processes to fabricate electrically conductive carbon electrodes. The stereolithography allows the structures to be 3D printed with very fine resolution and desired shapes. The resin is then chemically modified to carbon using pyrolysis to enhance electrochemical performance. The electrochemical characteristics of 3D printing carbon electrodes are assessed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The specific capacitance of 3D printing carbon electrodes is much higher than the same sized platinum (Pt) electrode. In-vivo electromyography (EMG) recording, 3D printing carbon electrodes exhibit much higher signal-to-noise ratio (40.63 ± 7.73) than Pt electrodes (14.26 ± 6.83). The proposed biofabrication method is envisioned to enable 3D printing in many emerging applications in biomedical engineering and electronics.

Outcomes of standard dose EC-MPS with low exposure to CsA in DCD renal transplantation recipients with DGF

AIMS

The lower limit of exposure to cyclosporine A (CsA) has not yet been established in donation after cardiac death (DCD) renal transplantation recipients with delayed graft function (DGF) receiving enteric-coated mycophenolate sodium (EC-MPS) therapy. Stable and adequate mycophenolic acid (MPA) dosing may facilitate lower CsA exposure after DCD renal transplantation in recipients with DGF without compromising safety.

METHODS

A 12-month, single-centre open-label prospective trial was performed in our centre. According to their DGF risk index using the previous DGF prediction models, we divided up the patients on oral CsA into either a DGF group (n = 26) and no DGF group (n = 48). All of the patients initially received the standard EC-MPS dosing (1440 mg/day). The initial dose of CsA in the low risk of DGF group was 4.5 mg/kg/day and in the high risk of DGF group was 2.5 mg/kg/day. Efficacy parameters, safety and tolerability were assessed over a 12-month study period.

RESULTS

The incidence of DGF was 18.5% in the 162 DCD recipients. Between the DGF group and the no DGF group, the 1-year patient survival and graft survival were not significantly different. The incidence of BPAR was higher in the DGF group (26.9% vs. 8.3%, p = 0.032). Most patients in the DGF group had recovery of renal function after 1 month. The adverse events between the two groups were not significantly different. The daily EC-MPS doses of the DGF group were significantly higher than the no DGF group before the 6-month follow-up period. There were no significant differences between the two groups regarding the mean AUC levels during the follow-up period.

CONCLUSIONS

These results show that low expose CsA with standard dosing of EC-MPS and thymoglobulin was efficacious, safe and well-tolerated in DCD renal transplant recipients with DGF in China. Furthermore, stable and adequate MPA exposure helped to reduce the dose of and exposure to CsA. Thus, this may lead to less-induced nephrotoxicity and better renal function recovery.

Phylogenetic analysis of Elymus (Poaceae) in western China

Elymus L. is often planted in temperate and subtropical regions as forage. Species in the genus have 5 allopolyploid genomes that are found in the grass tribe Triticeae. To determine the phylogenetic relationships in Elymus species from western China, we estimated phylogenetic trees using sequences from the nuclear ribosomal internal transcribed spacer and non-coding chloroplast DNA sequences from 56 accessions (871 samples) of 9 polyploid Elymus species and 42 accessions from GenBank. Tetraploid and hexaploid Elymus species from western China had independent origins, and Elymus species from the same area or neighboring geographic regions were the most closely related. Based on the phylogenetic tree topology, the St- and Y-genomes were not derived from the same donor and Y-genome likely originated from the H-genome of Hordeum species, or they shared the same origin or underwent introgression. The maternal genome of tetraploid and hexaploid Elymus species originated from species of Hordeum or Pseudoroegneria. Additionally, Elymus species in western China began diverging 17-8.5 million years ago, during a period of increased aridification as a consequence of the Messinian salinity crisis. Elymus species adapted to drought and high salinity may have developed based on the environmental conditions during this period. Elymus evolution in western China may have been affected by the uplift of the Qinghai-Tibetan Plateau (5 million years ago), when Elymus seeds were dispersed by gravity or wind into a newly heterogeneous habitat, resulting in isolation.

Application of multi-output support vector regression on EMGs to decode hand continuous movement trajectory

Applications of neural machine interfaces have received increased attention during the last decades. It is crucial to realize the continuous control of prosthetic devices based on biological signals. In order to deal with the highly nonlinear relationship between the Electromyography (EMG) signals and motion, this study presents a novel decoding approach which employs multi-output support vector regression (M-SVR). The proposed M-SVR is compared with other popular regression techniques and the experimental results demonstrate the effectiveness of M-SVR in hand continuous movement trajectory reconstruction.

Intraoperative detection of sentinel lymph node metastases in breast carcinoma by Fourier transform infrared spectroscopy

Background

Sentinel lymph node (SLN) biopsy is a routine surgical staging procedure in clinically lymph node-negative breast cancer. Fourier transform infrared (FTIR) spectroscopy, a technique based on the biochemical composition of the tissue, has previously been found to be capable of differentiating between normal and malignant tissue. The aim of the present study was to explore the intraoperative use of FTIR spectroscopy for rapidly identifying metastatic SLNs, and distinguishing between metastatic and non-metastatic tissue.

Methods

Freshly removed SLNs from patients with breast cancer were analysed. Samples were measured by FTIR spectroscopy before histopathological diagnosis. The FTIR spectrum of each sample identified ten bands from 2000 to 900 cm−1. The peak position, intensity and full width at half maximum of each absorbent band were measured, and the relative intensity ratios calculated. Canonical discriminant analysis was performed to discriminate between metastatic and non-metastatic samples.

Results

A total of 149 SLNs were removed from 49 patients. Histopathological examination confirmed 38 metastatic and 111 non-metastatic SLNs. Eighteen of 29 parameters were significantly different between the metastatic and non-metastatic SLNs. Five parameters were selected as independent factors to form discriminant functions. The sensitivity, specificity and accuracy of this method were 94·7, 90·1 and 91·3 per cent respectively. The accuracy of histological analysis of frozen sections was 100 per cent.

Conclusion

FTIR spectroscopy is a promising technique for the real-time diagnosis of SLN metastasis during breast cancer surgery. Surgical relevanceSentinel lymph node (SLN) biopsy is a highly accurate predictor of overall axillary status and has become the standard in disease staging in clinically node-negative breast cancer. A rapid and accurate intraoperative assessment of metastatic spread to the SLN provides the necessary information for the surgeon to proceed with immediate axillary dissection.The results of this research indicate that Fourier transform infrared (FTIR) spectroscopy is a rapid, accurate, non-destructive and cost-effective molecular method that can be used to detect SLN metastasis during surgery.FTIR analysis could be useful for the intraoperative diagnosis of lymph node metastases at large institutions, thereby reducing the workload of pathologists, as well as in regions lacking pathologists such as in developing countries.

Which is more suitable for kidney transplantation at the early post-transplantation phase in China - low dosing or standard dosing of enteric-coated mycophenolate sodium?

AIMS

To investigate the pharmacokinetics of enteric-coated mycophenolate sodium (EC-MPS) and the clinical outcome in kidney transplant recipients in the early post-transplantation phase. Then explain which regimen is more suitable for Chinese renal transplant recipients.

METHODOLOGY

In total, 60 de novo kidney transplant recipients treated with tacrolimus and steroids were randomised to receive EC-MPS at standard dose (SD; 1440 mg/day; n = 28) or low dose (LD; 1080 mg/day; n = 32). Efficacy parameters, safety and tolerability were assessed over a 6-month study period. Full mycophenolic acid (MPA) areas under the curve (AUCs) were completed on days 3 and 5, whereas a three-point limited sampling strategy (LSS) was utilised for MPA AUC assessments at 2 weeks and months 1, 3 and 6 (the LSS for three-time-point MPA AUC 0-12 h (mg h/l) = 15.99 + 0.87C1 h  + 0.68C2 h  + 7.85C4 h ; r(2)  = 0.8670.

RESULTS

The mean AUC levels at day 3 and day 5 in the SD group were significantly higher than in the LD group (57.4 mg·h/l vs. 38.2 mg·h/l and 59.3 mg·h/l vs. 44.8 mg·h/l, respectively, p < 0.01). There was a trend for fewer clinically diagnosed acute rejections in the SD group vs. the LD group at 6 months (7.1% vs. 12.5%). This trend was also present when acute rejection was analysed as biopsy-proven cases. There were significantly more acute rejections (all definitions) in patients with MPA AUC levels < 30 mg·h/l compared with those with MPA AUC levels ≥ 30 mg·h/l within 6 months (p < 0.05). Renal function, incidence of infection and haematological disorders were not significantly different in either study group.

CONCLUSIONS

Early adequate MPA exposure in renal transplant recipients can be achieved with a higher starting dose. In addition, a SD regimen was as well-tolerated as a LD regimen. Furthermore, early adequate MPA exposure significantly lowered the rate of acute rejection without compromising safety and tolerability.

SrRietveld: a program for automating Rietveld refinements for high-throughput powder diffraction studies

SrRietveldis a highly automated software toolkit for Rietveld refinement. Compared to traditional refinement programs, it is more efficient to use and easier to learn. It is designed for modern high-throughput diffractometers and is capable of processing large numbers of data sets with minimal effort. The software currently uses conventional Rietveld refinement engines, automatingGSASandFullProfrefinements. However, as well as automating and extending many tasks associated with these programs, it is designed in a flexible and extensible way so that in the future these engines can be replaced with new refinement engines as they become available.SrRietveldis an open-source software package developed in Python.

Specificity and kinetics of norovirus binding to magnetic bead-conjugated histo-blood group antigens

AIMS

To characterize the specificity and effect of pH and ionic strength on the kinetics of virus binding to histo-blood group antigens (HBGA)-conjugated magnetic beads.

METHODS AND RESULTS

HBGAs from porcine gastric mucin (PGM) have been conjugated to magnetic beads (PGM-MB) for concentration of NoV. A GII.4 virus was used for the detailed binding kinetics study and a panel of genogroup I (GI) NoVs, genogroup II (GII) NoVs and recombinant NoVs (rNoVs) were used for specificity and binding efficiency assays. We determined that NoV can be captured after 15min of incubation with PGM-MB, and virus recovery efficiency is decreased after extended incubation times. rNoV binding as measured by ELISA and NoV recovery as measured by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), were both enhanced significantly at acidic pH conditions. rNoV binding to PGM as measured by ELISA was increased up to 66%. While real-time RT-PCR analyses suggest that NoV could be concentrated as much as 1000-fold at neutral pH, up to 3·4-fold further increase of NoV recovery was achieved by adjusting the pH of the sample to 3·0-4·2. Variation between GI and GII viral binding to the PGM-MB at basic pH was observed. All five GI rNoVs tested and 6 of 9 GII rNoVs were captured by PGM. All eight GI strains tested were concentrated by PGM-MB, ranging from 28-fold (GI.4) to 1502-fold (GI.1). Eleven of 13 GII strains were concentrated from 30-fold (GII.5) to 1014-fold (GII.4, lab strain) by PGM-MB. GI and GII rNoVs viral capsid proteins were recovered with high salt conditions, but results were inconsistent for whole virus recovery.

CONCLUSIONS

All GI and 85% of GII NoVs tested could be captured and concentrated by PGM-MB method. The binding occurred rapidly and was enhanced at low pH.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results facilitated development of a prototype method for sensitive detection of NoV in samples requiring larger volumes.

Inhibition of the growth of human hepatoma cell line bothin vitro andin vivo by transducing CKI genep21 ( WAF-1 ) with GE7 targeting gene delivery system

The EGF receptor-mediated targeting gene delivery system GE7 was used to transduce exogenous genepCEP-p21 ( WAF-1 ) into human hepatocellular carcinoma cell bothin vitro andin vivo. Afterin vitro transduction of the exogenous gene, the growth of the cell lines SMMC-7721 and BEL-7402 was significantly inhibited compared with the control. On day 8 the inhibition rates of the above cell lines reached 56.0% and 66.7%, respectively. Thein vivo experiment showed that the growth of human hepatoma transplanted in nude mice injected with GE7 gene delivery system subcutaneously once a week for 3 weeks was remarkably inhibited compared with that of untransfected control. The average tumor weight of the experiment group was (0.083 +/-0.043) g, while that of the control group was (0.281 +/-0.173) g. The difference is significant (P<0.05). It was indicated that GE7 gene delivery system could efficiently transduce exogenous genepCEP-p21 ( WAF-1 ) into hepatoma cell with high EGF receptor expression, and inhibit the cell growth with high efficacy bothin vivo andin vitro.

Norovirus binds to blood group A-like antigens in oyster gastrointestinal cells

AIMS

To determine if histo-blood group antigens (HBGA) present in oyster gastrointestinal (GI) cells mediate accumulation of human noroviruses (NoV) in oyster GI cells.

METHODS AND RESULTS

HBGA-specific monoclonal antibodies (MAbs) were used to determine the presence of the corresponding HBGA in oyster GI cells. All oyster samples tested contained type A-like HBGA in GI tissue as measured by ELISA. Recombinant Norwalk virus viral like particles (rNVLP) were bound to plates coated with oyster GI homogenate. The binding was inhibited when rNVLPs were pre-incubated with MAbs specific for type A HBGA, or samples of human saliva from type A individuals. Co-localization of rNVLP and type A-like HBGA, but not type B-like or type H-like HBGA, on GI epithelial cells was observed by immunofluorescent histochemical staining and three-channel confocal scanning laser microscopy.

CONCLUSION

Type A-like HBGA is present in oyster GI cells and responsible for binding of rNVLP.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of the presence of type A-like HBGA in oyster GI cells and the specific binding of rNVLP to type A-like HBGA on oyster GI cells. The results of this study suggest that human NoV concentrate in oyster GI cells by specific binding to concentrated type A-like HBGA rather than by a nonmolecular entrapment within the tissues.

Detection of norovirus capsid proteins in faecal and food samples by a real time immuno-PCR method

AIMS

To develop a sensitive real time immuno-polymerase chain reaction (rtI-PCR) method for detecting norovirus (NV) capsid protein in food samples.

METHODS AND RESULTS

The viral antigens were captured by two polyclonal antisera against recombinant Norwalk viral-like particles (rNVLPs). Biotin-conjugated antibodies, avidin and biotin-conjugated DNA reporter were used to convert the protein signals into DNA signals. The reporter DNA was then amplified by addition of primers and PCR. A real time PCR method was used in order to perform a quantitative post-PCR analysis. One hundred rNVLPs (10 fg) and a NV sample containing 660 rNVLPs equivalent particle units (66 fg) could be detected by this method.

CONCLUSION

The PCR inhibitors present in the food samples had minimal effect on antigen capture and were removed by multiple wash steps during the rtI-PCR procedure. The sensitivity of rtI-PCR was >1000-fold higher than the standard enzyme-linked immunosorbent assay and approximately 10 times higher than reverse transcription PCR in detection of NV capsid protein in stool and food samples.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of a rtI-PCR method to detect NV in contaminated food samples without concentration or purification of the virus.

Porcine gastric mucin binds to recombinant norovirus particles and competitively inhibits their binding to histo-blood group antigens and Caco-2 cells

AIMS

To determine if human noroviruses (NV) bind to histo-blood group antigens (HBGA) from pig gastric mucosa.

METHODS AND RESULTS

An assay was developed to measure the inhibition of binding of recombinant norovirus-like particles (rNVLP) to HBGA in human saliva by porcine gastric mucin (PGM). The binding of rNVLP to HBGA could be inhibited by PGM in a dose-dependent pattern. Also, rNVLP could be captured effectively by PGM coated directly on plates and was detected by binding of polyclonal antibodies against rNVLP. Similarly, the binding of rNVLP to PGM could be inhibited effectively by HBGA in human saliva, and by Lewis b and Lewis d synthetic oligosaccharides (OS), but not inhibited effectively by an H3 OS or by purified bovine submaxillary gland mucin. Preincubation of rNVLPs with PGM completely inhibited their binding to human Caco-2 cells.

CONCLUSIONS

PGM binds effectively to rNVLPs and competitively inhibits rNVLPs binding to human HBGA and Caco-2 cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of the binding of glycoproteins from animal gastric mucosa to human NVs. This study highlights the importance of further characterizing the NV incidence and infections in nonhuman animal hosts and the possibility that NV is a zoonotic disease.

[Construction of mucosal vaccine derived from HBV surface antigen epitope A and the assay of its immunogenicity]

The fusion gene of HBV(adr) surface antigen epitope and B subunit of Cholera toxin was constructed and expressed successfully in E. coli at high yield. After denaturation-renaturation process, SDS-PAGE analysis showed that most of the renatured product reassociated in a pentameric form which was the same as natural CTB. Western blot analysis indicated that the immunogenicity of HBsAg antigen epitope was conserved. Moreover, ELISA analysis of the sera of orally, intranasally and intraperitoneally immunized mice showed that the circulating IgG antibodies to HBsAg were developed. The results may be helpful for constructing the novel mucosal vaccine with high efficacy.

[Expression of two truncated enhancin gene from Helicoverpa armigera granulosis virus in E. coli and its preliminary bioassay]

The plasmids pET-30a-Ben and pET-30a-Den which included 1.7 kd and 2.2 kb fragments of 5'-terminal of HaGV enhancin gene were obtained by cutting recombinant plasmid pET-30a-En with Bal I and Dra I respectively. Two fragments were expressed in E. coli successfully and the products were named Ben and Den respectively. The enhancement, which Ben and Den enhance the infectivity of HaNPV and Bt in 3rd larvae of Helicoverpa armigera, was studied. The results indicated that there was increase of the mortality of 10.5%-26.5% and the LT50 decrease of 0.9 d causes by adding Ben, while Den could increase the mortality by 10.2%-33.0% and decrease the LT50 by 1.2 d-1.9 d. The preliminary bioassay on Bt against Helicoverpa armigera indicated the recombinant enhancin could increase the mortality of larvae by 20.7%-35.4%, Den by 16.7%-31.5%, Ben by 11.7%-27.4%.

[Immunorelated pancytopenia]

OBJECTIVE

A report of a group of patients with pancytopenia which might be related to abnormal immunity.

METHODS

The clinical and laboratory features of 29 patients with positive bone marrow mononuclear cell (BMMNC) Coombs tests were analyzed.

RESULTS

Most of these cases were pancytopenia with normal or decreased bone marrow cellularities and increased normoblasts. They were all found to have negative results of conventional hemolysis tests and hematopoietic nutrient determination and had no evidence of malignant clonal hematopoiesis. However, all of them showed positive BMMNC-Coombs test and good response to corticosteroids.

CONCLUSION

Immunorelated pancytopenia might be caused by abnormal immunity (especially autoantibody) mediated destruction or abnormal function of blood cells. It is beneficial to differentiate immunorelated pancytopenia from aplastic anemia or myelodysplastic syndromes.

Crystal structure of the oligomerization domain of NSP4 from rotavirus reveals a core metal-binding site

During the maturation of rotaviral particles, non-structural protein 4 (NSP4) plays a critical role in the translocation of the immature capsid into the lumen of the endoplasmic reticulum. Full-length NSP4 and a 22 amino acid peptide (NSP4(114-135)) derived from this protein have been shown to induce diarrhea in young mice in an age-dependent manner, and may therefore be the agent responsible for rotavirally-induced symptoms. We have determined the crystal structure of the oligomerization domain of NSP4 which spans residues 95 to 137 (NSP4(95-137)). NSP4(95-137) self-associates into a parallel, tetrameric coiled-coil, with the hydrophobic core interrupted by three polar layers occupying a and d-heptad positions. Side-chains from two consecutive polar layers, consisting of four Gln123 and two of the four Glu120 residues, coordinate a divalent cation. Two independent structures built from MAD-phased data indicated the presence of a strontium and calcium ion bound at this site, respectively. This metal-binding site appears to play an important role in stabilizing the homo-tetramer, which has implications for the engagement of NSP4 as an enterotoxin.

[Molecular cloning of enhancin gene from Helicoverpa armigera granulosis virus and its expression in E. coli]

In order to provide recombinant enhancin for studying its mechanism of increasing the mortality of larvae infected by HaNPV and creating new insecticide, enhancin gene from Helicoverpa armigera granulosis virus was amplified by PCR technique. 2.7 kb fragment of enhancin gene was cloned into EcoRI/XbaI site of plasmid pBluescript KS. Sequence analysis revealed that enhancin gene was similar with that reported in the literature except eight nucleotides and five amino acids. Thereby enhancin gene was inserted into vector pET-30a and expressed successfully in Escherichia coli BL21(DE3). The preliminary bioassay of expressed product and HaNPV indicated that mortality of larvae increased 31.7%-34.1% in 7 post-infection days and the LT50 decreased at least 1.5-2.1 days.

Sperm function tests after vasovasostomy

AIM

To evaluate the sperm function after vasovasostomy.

METHODS

Semen samples from 42 subjects after vasovasostomy (Group A: 1-6 months, Group B: 6-12 months; Group C: 12-18 months after vasectomy reversal) were investigated. Semen from 34 normal fertile men was used as controls. Sperm function tests, including hypoosmotic swelling test (HOST), acridine orange (AO) fluorescence, acrosome reaction (triple-stain), cervical mucus penetration test (CMPT), etc were done.

RESULTS

After vasectomy reversal, the percentage of HOST was significantly lower than that of the normal fertile men. In regard to AO, there were no significant differences between the three vasovasostomy groups and between these 3 groups and the controls. With triple-stain, the percentage of normal acrosome reaction was significantly lower in Group A as compared with the controls, but not in Groups B and C. There were no significant differences in the results of CMPT between the vasovasostomy groups and the controls. However, the number of "poor" type was significantly higher in Groups A and C than in the controls; the percentage of "negative" type were higher in Groups A and B than in the controls.

CONCLUSION

After vasovasostomy a lower level of HOST remained for one year and gradually recovered after one year. Six months after vasectomy reversal, the percentage of acrosome reaction could be changed from lower level to normal range. The data of AO indicated that the genetic material (double-stranded DNA) in spermatozoa was not affected by vasovasostomy. To evaluate the result of CMPT after vasectomy reversal, not only the normal results but also the abnormal results ("poor" and "negative" types) should also be considered.

[Modified vascular endothelia growth factor receptor-mediated targeting nonviral gene delivery system and in vivo beta-gal transducing experiment]

OBJECTIVE

To investigate whether the modified vascular endothelial growth factor (VEGF) receptor-mediated targeting nonviral gene delivery system is efficient in transducing exogenous gene.

METHODS

We detected the expression of VEGF receptor on some tumor models by immunohistochemistry at first and selected nine models, i.e. SMMC-7721, SK-OV-3, H128, SPC-A1, LoVo, MKN-45, BCaP-37, A375, cervical cancer xenograft and hepatoma xenograft. Then we prepared two complexes, GV1-P.L./beta-gal and GV2-P.L./beta-gal, and injected the two complexes subcutaneously into nude mice around the tumor. The expression of the reporter gene was observed in the vascular endothelial cells and some tumor cells with highly expressed VEGF receptor.

RESULTS

GV2 gene delivery system could transduce exogenous gene into vascular endothelial cells and subcutaneously transplanted tumors such as SK-OV-3, and cervical xenograft which were rich of VEGF receptor on the surface of the tumor cell. The expression reached a high level at day 3 and decreased eventually until the 3(rd) week. There was no expression in the heart and lung but low expression was seen in the spleen. GV1 gene delivery system also transduced exogenous gene into the endothelial cells but with low efficiency.

CONCLUSION

This system can specifically transduce beta-gal to cells rich of VEGF receptor but not to cells with undetectable VEGF receptor. The targetability of this modified system is increased as compared to the system previously reported.

The authentic sequence of rotavirus SA11 nonstructural protein NSP4

Recent studies demonstrate that the rotavirus nonstructural protein NSP4 functions as an enterotoxin and plays an important role in viral pathogenesis. Previous in vitro studies of NSP4 have used a cDNA clone of gene 10 derived from the prototypic rotavirus strain, SA11. We recently compared the sequence of the commonly used NSP4 cDNA with the sequence obtained from several SA11 isolates by direct sequencing of reverse transcription polymerase chain reaction products. One codon difference was identified between the cDNA clone and the SA11 virus isolates, and this resulted in a predicted amino acid substitution at position 47. The cDNA sequence specifies an asparagine at position 47, and the SA11 virus gene 10 encodes a hisitidine. To determine if this amino acid substitution altered the function of NSP4, we analyzed the ability of both NSP4-Asn47 and NSP4-His47 to regulate intracellular calcium levels and exhibit cell cytotoxicity. Our results indicate that the expression of NSP4-His47 from a recombinant baculovirus displays enhanced cytotoxicity and calcium flux.

[HIM82 protects RBC from the ROS damage produced by activated PMN]

OBJECTIVE

To investigate the protection of RBC from ROS damage produced by activated PMN with McAb-HIM82.

METHODS

RBC was injured by ROS produced from PMN activated with PMA and the injury was antagonised by adding HIM82(30 micrograms/ml) to the medium with PMN.

RESULTS

Comparing antagonitic group with injured group, the activity of AchE on RBC membrane after adding HIM82 was recovered from (71.36 +/- 22.15)% to (87.66 +/- 14.78)% (n = 6 P < 0.001). The proportion of MDA was decreased from (52.42 +/- 20.63)% to (23.81 +/- 12.4)%(n = 9 P < 0.001); the hemolysis rate was decreased from (80.76 +/- 20.23)% to (66.30 +/- 7.08)% (n = 6 P < 0.05);

CONCLUSIONS

The result showed that the McAb HIM82 could protect RBC from injury by down-reguration of ROS level in activated PMN. It could help to establish a newer approach to study the regulation effect of McAb HIM82 on ROS production from PMN actived with relerant cytokines as well as mediators.

The rotavirus nonstructural glycoprotein NSP4 possesses membrane destabilization activity

During a unique morphogenetic process, rotaviruses obtain a transient membrane envelope when newly synthesized subviral particles bud into the endoplasmic reticulum (ER). As rotavirus particles mature, they lose their transient membrane and a layer of the glycoprotein VP7 forms the virion outer capsid shell. The nonstructural glycoprotein NSP4 functions as an intracellular receptor in the ER membrane (K. S. Au, W. K. Chan, J. W. Burns, and M. K. Estes, J. Virol. 63:4553-4562, 1989), and it has been hypothesized that NSP4 is involved in the removal of the envelope during viral morphogenesis (M. K. Estes and J. Cohen, Microbiol. Rev. 53:410-449, 1989; B. L. Petrie, M. K. Estes, and D. Y. Graham, J. Virol. 46:270-274, 1983). The purpose of the present study was to determine if NSP4 has a direct membrane destabilization activity (MDA) by using liposome leakage assays and electron microscopic visualization of liposome, microsome, and viral envelope disruption. The fluorescent marker (calcein) incorporated into liposomes was released when the liposomes were incubated with purified NSP4. A region corresponding to amino acid residues 114 to 135 of NSP4 also released calcein from liposomes. NSP4(114-135) peptide-specific antibody completely blocked the MDA of the purified NSP4 protein. These results suggest that this region contains at least part of the functional domain of NSP4. Liposomes composed of phosphatidylcholine and microsomes (to simulate ER membranes) were broken when observed by electron microscopy after incubation with NSP4 or the NSP4(114-135) peptide. In contrast, the envelope of Sendai virus, which is derived from cytoplasmic membranes, and erythrocytes were not disrupted by NSP4 and the NSP4(114-135) peptide. These results provide direct evidence that NSP4 possesses MDA and suggest that it can cause ER membrane damage. Therefore, NSP4 might play an important role in the removal of the transient envelope from budding particles during viral morphogenesis. A model for the MDA of NSP4 in viral morphogenesis is proposed.

Age-dependent diarrhea induced by a rotaviral nonstructural glycoprotein

The rotavirus nonstructural glycoprotein NSP4 is an intracellular receptor that mediates the acquisition of a transient membrane envelope as subviral particles bud into the endoplasmic reticulum. NSP4 also causes an increase in intracellular calcium in insect cells. Purified NSP4 or a peptide corresponding to NSP4 residues 114 to 135 induced diarrhea in young (6 to 10 days old) CD1 mice. This disease response was age-dependent, dose-dependent, and specific. Electrophysiologic data from intestinal mucosa showed that the NSP4 114-135 peptide potentiates chloride secretion by a calcium-dependent signaling pathway. Diarrhea is induced when NSP4, acting as a viral enterotoxin, triggers a signal transduction pathway.

Rotavirus protein expression is important for virus assembly and pathogenesis

Rotaviruses have a unique morphogenesis in which particles obtain a transient membrane-envelope as newly made subviral particles bud into the endoplasmic reticulum (ER). This process is mediated by a viral nonstructural glycoprotein, NSP4. We have found that NSP4 has pleiotropic properties that became evident following expression of this protein in eukaryotic cells. NSP4 expressed in insect cells bound double-layered rotavirus particles in a manner similar to receptor-ligand interactions and this interaction is thought to trigger the particle budding process. Expression of NSP4 in insect cells also increases intracellular calcium ([Ca2+]i) levels and this effect may explain the toxicity of this protein in eukaryotic cells. Increases in [Ca2+]i levels in insect cells also are observed following exogenous addition to cells of purified NSP4 or of a synthetic peptide of NSP4. Experiments to determine the mechanism by which NSP4 causes an increase in [Ca2+]i showed that Ca2+ is released from a subset of the thapsigargin-sensitive store [endoplasmic reticulum (ER)]. However, exogenously added and endogenously expressed NSP4 use different mechanisms to alter the Ca2+ permeability of the ER membrane. We hypothesize that NSP4-mediated changes in ER membrane permeability trigger viral budding into the lumen of the ER, and eventually induce cell death and release of virus particles from infected cells. We also propose that release of NSP4 following cell lysis and the concomitant stimulation of a Ca2+ signal transduction pathway in neighboring cells contributes to altered ion transport in intestinal epithelium resulting in diarrheal disease.

The rotavirus nonstructural glycoprotein NSP4 mobilizes Ca2+ from the endoplasmic reticulum

We previously reported that expression of rotavirus nonstructural glycoprotein NSP4 is responsible for an increase in cytosolic free Ca2+ concentration ([Ca2+]i) in Spodoptera frugiperda (Sf9) insect cells (P. Tian, Y. Hu, W. P. Schilling, D. A. Lindsay, J. Eiden, and M. K. Estes, J. Virol. 68:251-257, 1994). The purpose of the present study was to determine the mechanism by which NSP4 causes an increase in [Ca2+]i by measuring the permeability of the cytoplasmic and endoplasmic reticulum (ER) membranes in recombinant-baculovirus-infected Sf9 cells. No obvious change in plasmalemma permeability to divalent cations was observed in cells expressing NSP4 compared with that in cells expressing another rotaviral glycoprotein (VP7) when the influx of Ba2+, a Ca2+ surrogate, was monitored. The basal Ca2+ permeability of the internal Ca2+ store was evaluated by measuring the release of Ca2+ induced by ionomycin, a Ca2+ ionophore, or thapsigargin, an inhibitor of the ER Ca(2+)-ATPase pump, following suspension of the cells in Ca(2+)-free extracellular buffer. Releasable Ca2+ decreased with time to a greater extent in cells expressing NSP4 compared with that in cells expressing VP7, suggesting that NSP4 increases the basal Ca2+ permeability of the ER membrane. To determine the possible mechanism by which NSP4 increases ER permeability, purified NSP4 protein or a 22-amino-acid synthetic peptide consisting of residues 114 to 135 (NSP4(114-135) was added exogenously to noninfected Sf9 cells during measurement of [Ca2+]i. Both NSP4 and the NSP4(114-135 peptide produced a time-dependent increase in [Ca2+]i that was attenuated by prior inhibition of phospholipase C with U-73122. Pretreatment of the cells with thapsigargin completely blocked the increase in [Ca2+]i produced by NSP4(114-135, but the peptide only partially reduced the change in [Ca2+]i produced by thapsigargin. No changes in [Ca2+]i were seen in cells treated with control peptides. These results suggest that (i) exogenous NSP4 increases [Ca2+]i through the activation of phospholipase C, (ii) Ca2+ release by exogenous NSP4 is from a store that is a subset of the thapsigargin-sensitive compartment, and (iii) amino acid residues 114 to 135 of NSP4 are sufficient for this activity. In contrast to exogenous NSP4, the mechanism by which endogenously expressed NSP4 increases [Ca2+]1 appears to be unrelated to phospholipase C, since no effect of U-73122 was seen on the elevated [Ca2+]1 in cells expressing NSP4 and exogenously applied NSP4(114-135) caused a further increase in [Ca2+]1 in cells expressing NSP4 protein.(ABSTRACT TRUNCATED AT 400 WORDS)

Antitumor activity of immunoconjugates composed of boanmycin and monoclonal antibody

Boanmycin (bleomycin A6, BM), an antitumor antibiotic, was conjugated to monoclonal antibodies including R19, H111 and CCT2. The immunoconjugates exhibited selective cytotoxicity to related target cells including cecum cancer Hce-8693 cells, liver cancer BEL-7402 cells and leukemia CEM cells. They were highly effective against related human tumor xenografts in nude mice, and the inhibition rates by the conjugates were much higher than those by free BM. The inhibition rate by R19-BM conjugate against human cecum cancer xenografts reached 90%. BY immunoelectron microscopy, CCT2-BM conjugate showed specific binding and internalization in leukemia CEM cells. The results indicate that boanmycin-monoclonal antibody immunoconjugates are highly active both in vitro and in vivo.

The nonstructural glycoprotein of rotavirus affects intracellular calcium levels

Rotavirus infection of monkey kidney cells has been reported to result in a significant increase in the concentration of intracellular calcium. This increase in intracellular calcium was associated with viral protein synthesis and cytopathic effects in infected cells. We tested the effect of individual rotavirus proteins on intracellular calcium concentrations in insect Spodoptera frugiperda (Sf9) cells. Insect cells were infected with wild-type baculovirus or baculovirus recombinants that contained an individual rotavirus gene. The cells were harvested at different times postinfection, and the intracellular calcium concentration was measured by using fura-2 as a fluorescent calcium indicator. We found that the concentration of intracellular calcium was increased nearly fivefold in infected Sf9 cells that expressed the nonstructural glycoprotein (NSP4) of group A rotavirus, and this increase in intracellular calcium concentration coincided with NSP4 expression. A similar result was observed in insect cells expressing NSP4 from a group B rotavirus, suggesting the conservation of this function among rotavirus groups. Expression of the other 10 rotavirus proteins or of wild-type baculovirus proteins in Sf9 cells did not significantly increase intracellular calcium levels. These results suggest that the nonstructural glycoprotein NSP4 is responsible for the increase in cytosolic calcium observed in rotavirus-infected cells.

[Ultrastructural study and localization of duck hepatitis B virus in the livers of experimentally infected ducks]

An electron microscopic study was performed to investigate the occurrence and localization of duck hepatitis B virus (DHBV) in the livers of infected Beijing ducks. DHBV-DNA was found in trace amounts in liver extract on 9th hours after infection by Southern blot hybridization and was found in serum on the 4th day of infection. Virus particles were recognized in the hepatocytes as early as the 3rd day of infection. Many incomplete virus particles, (50 to 80 nm in diameter), and a few complete virus particles, (45-65 nm in diameter), were seen in cisternae of rough and smooth endoplasmic reticula of hepatocytes, clusters or scattered core particles, (35-38 nm in diameter), were seen in the cytoplasm, some core particles were found in nuclei of liver cells where core assembly might be occur. The similarities and differences of the localizations of DHBV and HBV in duck liver cells are discussed.

Mechanism of soft X-ray radiation damage on glycine by XPS

This paper reports the behaviour of radiation damage of solid glycine in a XPS spectrometer equipped with Mg and Al X-ray sources. The main results are as follows: (i) the kinetics of the damage process obeys the first-order rate law, (ii) decarboxylation can be deduced, and (iii) deamination does not occur, but the nitrogen atoms in original molecules are transformed into a new chemical form with higher electron density by photo-reduction.