Noncontact Electromagnetic Wireless Recognition for Prosthesis Based on Intelligent Metasurface

With the development of artificial intelligence and Internet of Things, hand gesture recognition techniques have attracted great attention owing to their excellent applications in developing human-machine interaction (HMI). Here, the authors propose a non-contact hand gesture recognition method based on intelligent metasurface. Owing to the advantage of dynamically controlling the electromagnetic (EM) focusing in the wavefront engineering, a transmissive programmable metasurface is presented to illuminate the forearm with more focusing spots and obtain comprehensive echo data, which can be processed under the machine learning technology to reach the non-contact gesture recognition with high accuracy. Compared with the traditional passive antennas, unique variations of echo coefficients resulted from near fields perturbed by finger and wrist agonist muscles can be aquired through the programmable metasurface by switching the positions of EM focusing. The authors realize the gesture recognition using support vector machine algorithm based on five individual focusing spots data and all-five-spot data. The influences of the focusing spots on the gesture recognition are analyzed through linear discriminant analysis algorithm and Fisher score. Experimental verifications prove that the proposed metasurface-based non-contact wireless design can realize the classification of hand gesture recognition with higher accuracy than traditional passive antennas, and give an HMI solution.

Effect of general anesthesia combined with epidural anesthesia on perioperative immune factors in cervical cancer

Cervical cancer (CC) is a common malignant tumor that seriously threatens the health and life of female patients. At present, surgical resection remains as the preferred treatment for CC.

Identification of O-GlcNAcylation Modification in Diabetic Retinopathy and Crosstalk with Phosphorylation of STAT3 in Retina Vascular Endothelium Cells

BACKGROUND/AIMS

Recently, we observed an increase in O-GlcNAc (O-linked-ß-N-acetylglucosamine) modification, and signal transducer and activator of transcription proteins 3 (STAT3) expression in primary retinal vascular endothelial cells (RVECs) under high glucose conditions and tissues altered by diabetic retinopathy (DR). In this study, we focused on the correlations between O-GlcNAcylation and STAT3 phosphorylation, and their potential effects with regards to DR.

METHODS

Expression of O-GlcNAcylation and STAT3 were detected in DR-affected tissues and primary RVECs. The relationship between O-GlcNAcylation and STAT3 was further delineated by immunoprecipitation and Western blot analysis. Effects of O-GlcNAcylation on human RVEC apoptosis and involved protein expression were assayed with flow cytometry and Western blot.

RESULTS

Global O-GlcNAcylation and pSTAT3 levels were significantly elevated in diabetic rat retina and primary RVECs under high glucose conditions. In vitro assays demonstrated that the Tyr705 site was sensitive to high glucose. While O-GlcNAcylation inhibited p727STAT3 expression, augmented O-GlcNAcylation could balance p705STAT3 expression within relatively high levels corresponding to vascular endothelial growth factor (VEGF) changes. Immunoprecipitation revealed that STAT3 was modified by O-GlcNAcylation and phosphorylation simultaneously. Next, we observed that overexpression of O-GlcNAcylation could relieve human RVEC apoptosis related to the JAK2-Tyr705STAT3-VEGF pathway.

CONCLUSION

O-GlcNAcylation could relieve RVECs apoptosis through the STAT3 pathway in DR, and O-GlcNAcylation combined with STAT3 phosphorylation might open up new insights into the mechanisms of DR and other diabetic complications.

POU2F1 promotes growth and metastasis of hepatocellular carcinoma through the FAT1 signaling pathway

Increasing evidence suggests that POU domain class 2 transcription factor 1 (POU2F1) participates in carcinogenesis and cancer progression via promotion of cell proliferation and metastasis; however, the functional role of POU2F1 in hepatocellular carcinoma (HCC) is largely unknown. In this study, we determined that POU2F1 was significantly up-regulated in HCC tumor tissue and cell lines. We demonstrated that POU2F1 over-expression promoted HCC cell proliferation, colony formation, migration, and invasion, while silencing of POU2F1 inhibited these malignant phenotypes. In vivo experiments indicated that knockdown of POU2F1 inhibited HCC cell metastasis and xenograft growth, whereas ectopic expression of POU2F1 promoted these cellular functions. Microarray analysis suggests that FAT atypical cadherin 1 (FAT1) can function downstream of POU2F1. Functionally, we demonstrated that POU2F1 knockdown induced growth suppression and metastasis inhibition of HCC cells and inactivated the FAT1 pathway, indicating that POU2F1 is a potential novel therapeutic target in HCC.

Transition from Anomalous Hall Effect to Topological Hall Effect in Hexagonal Non-Collinear Magnet Mn3Ga

We report experimental observation of large anomalous Hall effect exhibited in non-collinear triangular antiferromagnet D0₁₉-type Mn₃Ga with coplanar spin structure at temperatures higher than 100 K. The value of anomalous Hall resistivity increases with increasing temperature, which reaches 1.25 μΩ · cm at a low field of ~300 Oe at room temperature. The corresponding room-temperature anomalous Hall conductivity is about 17 (Ω · cm)⁻¹. Most interestingly, as temperature falls below 100 K, a temperature-independent topological-like Hall effect was observed. The maximum peak value of topological Hall resistivity is about 0.255 μΩ · cm. The appearance of the topological Hall effect is attributed to the change of spin texture as a result of weak structural distortion from hexagonal to orthorhombic symmetry in Mn₃Ga. Present study suggests that Mn₃Ga shows promising possibility to be antiferromagnetic spintronics or topological Hall effect-based data storage devices.

Anti-site-induced diverse diluted magnetism in LiMgPdSb-type CoMnTiSi alloy

The effect of three kinds of anti-site disorder to electronic structure and magnetic properties of the LiMgPdSb-type CoMnTiSi alloy are investigated. It was found the Mn-Ti anti-site disorder can induce the diluted magnetism in CoMnTiSi matrix. The magnetic structure has an oscillation between the ferromagnetic and antiferromagnetic states with the different degree of Mn-Ti anti-site disorder. Two novel characteristics: the diluted antiferromagnetic half-metallicity and the diluted zero-gap half-metallity are found in the different degree range of the Mn-Ti anti-site disorder. The Co-Mn and Co-Ti anti-site disorder have little effect on the magnetic properties. The width of energy gap and the intensity of DOS at the Fermi level can be adjusted by the degree of Co-Mn or Co-Ti anti-site disorder. The independent control to the carrier concentration and magnetization can be realized by introducing the different anti-site disorder.

Induction and identification of Stylosanthes guianensis tetraploids

Stylosanthes guianensis is an elite and important forage legume species, which is extensively cultivated in tropical areas. Polyploid breeding via exposure to colchicine is a conventional and practical method to improve varieties of S. guianensis. Terminal buds of S. guianensis Reyan No.5 seedlings were treated with different concentrations of colchicine (0.00, 0.05, 0.10, 0.15, 0.20, and 0.25%) for 24, 48, and 72 h. Morphological and cytological variants were observed at a frequency of <96% among transplanted seedlings. The cytogenetic analysis of young leaf cells was conducted on all variants to identify their ploidy levels. The most efficient procedure for tetraploid production was the treatment of seedling apical buds with 20% colchicine for 48 h, with the tetraploid induction rate being 10%. This is a relatively simple and reliable method for the production of tetraploidy in S. guianensis.

The augmentation of O-GlcNAcylation reduces glyoxal-induced cell injury by attenuating oxidative stress in human retinal microvascular endothelial cells

It has recently been reported that O-linked β-N-acetyl glucosamine (O-GlcNAc) modification (a simple intracellular serine (Ser)/threonine (Thr)-linked monosaccharide) in human retinal microvascular endothelial cells (HRECs) is related to diabetic retinopathy (DR). During O-GlcNAcylation, O-GlcNAc is added to Ser and Thr residues. As the generation of reactive oxygen species (ROS) is one of the characteristics of advanced glycation end product (AGE) injury, and the most important key pathogenic factor of DR, in the present study, we aimed to investigate the association between O-GlcNAcylation and ROS generation in order to ascertain whether O-GlcNAcylation mitigates cellular injury through the generation of ROS. For this purpose, HRECs were divided into 4 groups as follows: HRECs treated with normal glucose (5 mM), HRECs treated with glyoxal (500 µM), glyoxal-treated HRECs also treated with 200 µM PUGNAc, and glyoxal-treated HRECs infected with O-GlcNAc transferase (OGT) siRNA. We detected increased O-GlcNAc levels and increased ROS production in the glyoxal-treated HRECs. The cellular redox status was determined by cellular ROS staining and by measuring the expression levels of the antioxidant genes, superoxide dismutase (SOD) and glutathione peroxidase (GPX). While the augmentation of O-GlcNAcylation following treatment with PUGNAc significantly attenuated the production of ROS (p<0.01) and increased the expression levels of SOD and GPX, the reduction of O-GlcNAcylation following infection with OGT siRNA, exacerbated the production of ROS (p<0.01) and decreased the expression of antioxidant genes. The effects of O-GlcNAcylation on the viability of HRECs were significant (p<0.01), particularly in the hydrogen peroxide (H2O2)-treated HRECs. Treatment with PUGNAc reduced glyoxal-induced cell apoptosis and transfection with OGT siRNA increased HREC apoptosis; these results were confirmed by flow cytometry and by the assessment of mitochondrial membrane potential. The augmentation of O-GlcNAcylation exerted cytoprotective effects on the HRECs by reducing the generation of ROS, increasing the expression of antioxidant genes, preventing the dissipation of mitochondrial membrane potential and preventing HREC apoptosis. Therefore, it can be concluded that O-GlcNAcylation plays a role in the early developmental process of DR.

First Report of Leaf and Sheath Spot Caused by Waitea circinata var. zeae on Paspalum vaginatum and Zoysia tenuifolia in China

Waitea circinata var. zeae was previously reported as the causal agent of leaf and sheath spot on Festuca arundinacea (1) and Panicum tennesseense (2) in the United States. In late May to mid-September 2013, a disease resembling leaf and sheath spot was observed on Paspalum vaginatum in fairways from several golf courses in Hainan Province, China. Affected plants initially had large yellow and brown spots on leaves and sheathes, then the whole plant turned yellowish-brown and eventually died. The same symptoms were also observed on a lawn established with Zoysia tenuifolia in Hainan University. Symptomatic leaves were surface sterilized in 1% hypochlorite for 1 min, rinsed with sterile water three times, and plated onto potato dextrose agar (PDA) amended with 0.01% gentamicin sulfate. Two Rhizoctonia-like fungal isolates were obtained from the diseased P. vaginatum (Isolate no. ML-WC1) and Z. tenuifolia (Isolate no. HNU-1) samples. After incubation on PDA for 1 week at 25°C, white mycelial colonies developed and eventually turned a salmon color with age. Small, white, spherical sclerotia (0.5 to 1 mm in diameter) were observed submerged throughout the agar media after incubation for 1 week and turned a reddish-brown color within 4 weeks. The two isolates were tentatively identified as W. circinata var. zeae based on these characteristics. The internal transcribed spacer (ITS) region of the ribosomal DNA gene was amplified and sequenced using primer pair ITS1/ITS4. The sequences of the two isolates (GenBank Accession Nos. KJ717943 and KJ717944) were more than 99% similar to W. circinata var. zeae (JQ688056 and JQ688059) sequences deposited in GenBank. To confirm pathogenicity, inocula were prepared by incubating autoclaved rye grains with strains ML-WC1 and HNU-1 for 2 weeks at 25°C. Ten colonized rye grains were uniformly spread around the crowns of 6-week-old P. vaginatum and Z. tenuifolia seedlings grown in 10-cm-diameter pots. Each isolate was placed in four separate pots and four control plants were treated with non-inoculated grain. All pots were covered with translucent plastic bags and placed in a greenhouse at 24 ± 2°C with a 12-h light/dark cycle. By 1 week post-inoculation, significant blighting of leaves and sheaths was observed, while non-inoculated plants showed no symptoms. W. circinata var. zeae was successfully re-isolated from symptomatic plants and confirmed by its Rhizoctonia-like mycelium and small, reddish-brown, spherical sclerotia on the PDA. Recently a related species, W. circinata var. circinata, causing brown ring patch on two cool-season grasses was reported in China (3). However, the isolates of W. circinata var. zeae were distinguished from W. circinata var. circinata base on ITS sequence data and morphological characters. To our knowledge, this is the first report of W. circinata var. zeae infecting P. vaginatum and Z. tenuifolia in China. References: (1) S. S. Martin, Jr. and L. T. Lucas. Plant Dis. 67:676, 1983. (2) N. A. Mitkowski. Plant Dis. 87:1006, 2003. (3) X. X. Ni et al. Plant Dis. 96:12, 2012.

Application of SRAP markers in the identification of Stylosanthes guianensis hybrids

Sequence-related amplified polymorphism (SRAP) is a new molecular marker technology developed based on polymerase chain reaction. The authenticity of 84 progenies of 8 hybrid combinations of Stylosanthes guianensis was identified by SRAP markers to select the true hybrids used in the present study. A total of 35 SRAP primer combinations were selected from the parents of 8 hybrid combinations. The selected polymorphism primer combinations were applied to identify the authenticity of all progenies. The male parents of the primer combinations had specific markers, whereas the female parents did not. 68 progenies exhibited male parent-specific bands, which were identified as true hybrids. The rest of the progenies were considered self-hybrids because of the absence of male parent-specific bands. The results of hybrid identification provided solid evidence for further studies of hybrids and demonstrated SRAP molecular markers as a useful technology for assessing the purity of S. guianensis hybrids.

Rapid and high-throughput identification of recombinant bacteria with mass spectrometry assay

OBJECTIVE

To construct a rapid and high-throughput assay for identifying recombinant bacteria based on mass spectrometry.

METHODS

Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques were used to identify 12 recombinant proteins (10 of Yersinia pestis, 1 of Campylobacter jejuni and 1 of Helicobacter pylori). A classification model for the various phase of recombinant bacteria was established, optimized and validated, using MALDI-TOF MS-ClinProTools system. The differences in the peptide mass spectra were analyzed by using Biotyper and FlexAnalysis softwares.

RESULTS

Models of GA, SNN, and QC were established. After optimizing the parameters, the GA recognition model showed good classification capabilities: RC=100%, mean CVA=98.7% (the CVA was 96.4% in phase 1, 100% in phase 2, 98.4% in phase 3, and 100% in phase 4, respectively) and PPV=95%. This model can be used to classify the bacteria and their recombinant, which only requires 3.7×103 cells for analysis. The total time needed is only 10 min from protein extraction to reporting the result for one sample. Furthermore, this assay can automatically detect and test 96 samples concurrently. A total of 48 specific peaks (9, 16, 9, and 14 for the four stages, respectively) was found in the various phase of recombinant bacteria.

CONCLUSION

MALDI-TOF MS can be used as a fast, accurate, and high-throughput method to identify recombinant bacteria, which provide a new ideas not only for recombinant bacteria but also for the identification of mutant strains and bioterrorism pathogens.

First Report of Limonomyces roseipellis Causing Pink Patch on Bermudagrass in South China

Hybrid bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy) is widely used on golf course putting greens in southern China. In September 2011, circular pink patches ranging from 10 to 20 cm in diameter were observed on putting greens established with cv. 'Tifgreen' on a golf course in Haikou, Hainan Province. There were approximately 50 pink patches on a putting green. Infected leaves were covered with pink, gelatinous fungal mycelium, which resulted in the production of chlorotic lesions. Lesions expanded, became water-soaked, and leaves died basipetally. A pink fungus, characterized by the presence of clamp connections, was consistently isolated from leaves of infected plants on a potato dextrose agar amended with 0.01% gentamicin sulfate. Based on morphological characteristics, the fungus was preliminary identified as Limonomyces roseipellis Stalpers & Loerakker, the causal agent of pink patch of turfgrass (2,3). To verify the identity, the internal transcribed spacer (ITS) of rDNA was amplified and sequenced using primers ITS1 and ITS4. Comparison with sequences in the GenBank database revealed that the ITS sequence (Accession No. KC193592) showed 98% homology with the sequence of L. roseipellis (EU622846). For pathogenicity tests, inoculum was prepared by culturing the fungus on an autoclaved mixture of 100 g of rye grain and 20 ml water for 3 weeks at 25°C. Six-week-old C. dactylon plants in 10-cm pots were inoculated by placing 2 g of infested grain in the center of the turf canopy, or 2 g sterilized, uninfested grain as a control, with four replications of each treatment. After inoculation, pots were covered with translucent plastic bags and placed in a greenhouse at 24 ± 2°C with a 12-h photoperiod (1). After 3 weeks, more than 70% of leaves in the infested pots showed symptoms identical to those observed under natural conditions while control plants remained asymptomatic. The fungus was reisolated from symptomatic plants. To our knowledge, this is the first report of L. roseipellis causing pink patch on hybrid bermudagrass in China. References: (1) L. L. Burpee and L. G. Goulty. Phytopathology 74:692, 1986. (2) J. D. Kaplan and N. Jackson. Plant Dis. 67:159, 1983. (3) J. A. Stalpers and W. M. Loerakker. Can. J. Bot. 60:529, 1982.

First Report of Laetisaria fuciformis Causing Red Thread on Seashore Paspalum (Paspalum vaginatum) in South China

Seashore paspalum (Paspalum vaginatum Swartz.) is a prostrate-growing, perennial, warm-season turfgrass native to tropical and coastal areas (2). Because of its good texture and natural tolerance to various environmental stresses, seashore paspalum has been introduced to golf courses in coastal regions of southern China. In April 2010, circular or irregular pink patches ranging from 5 to 50 cm in diameter were observed in the golf course fairway and rough established with cv. Salam on two golf courses in Haikou, Hainan Province, China. When morning dew was present or rainfall occurred, a pink layer of gelatinous fungal growth could be observed on leaves and sheaths. The green leaves of infected plants initially became water soaked, then tan to bleached, shriveled, and infested with pink or reddish, gelatinous, stranded hyphae. The hyphae matted together, then formed threadlike or antlerlike stromata from the tips of blighted leaves. Two isolates from each golf course were collected by plating diseased leaf blades, stromata, or hyphal aggregates from the blighted leaves directly onto antibiotic (0.01% gentamicin sulfate) amended potato dextrose agar. To confirm pathogenicity, isolates were inoculated on 6-week-old P. vaginatum (cv. Seaspray) planted (0.5 mg seed/cm^-2) in 10-cm pots. Inoculum was prepared by culturing isolates separately on an autoclaved mixture of 100 g of rye grain and 20 ml of water for 3 weeks at 25°C. Pots were inoculated by placing 2 g of infected grain within the center of the turf canopy or 2 g of sterilized, uninfested grains to serve as controls, with four replications of each treatment. After inoculation, each pot was placed in a translucent plastic bag and placed into a greenhouse at 24 ± 2°C with a 12-h photoperiod (1). Two days after inoculation, the fungus was observed on the leaves. Approximately 40% of leaves in inoculated pots were necrotic after 7 days, and this increased to 80% after 21 days. Diseased plants in inoculated pots displayed symptoms similar to those observed in the field and no symptoms were detected on the control plants. The two isolates were successfully reisolated from all symptomatic tissues, completing Koch's postulates. Sequences of mitochondrial small subunit ribosomal RNA (mt-SSU) were amplified from the two isolates by primers MS1 and MS2, and the sequences showed 99% similarity with Laetisaria fuciformis from the NCBI database (Accession No. AY293232). Red thread on turfgrass has been commonly observed in temperate climates during periods of cool and humid weather (3). To our knowledge, this is the first report of L. fuciformis causing red thread on P. vaginatum or from any host plant in China. References: (1) L. L. Burpee and L. G. Goulty. Phytopathology. 74:692, 1984. (2) R. R. Duncan and R. N. Carrow. Seashore Paspalum: The Environmental Turfgrass. John Wiley and Sons, Toronto, ON, Canada, 2000. (3) R. W. Smiley et al. Page 38 in: Compendium of Turfgrass Diseases. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2005.

Phosphorus release from ash and remaining tissues of two wetland species after a prescribed fire

Dead plant tissues and ash from a prescribed fire play an important role in nutrient balance and cycling in the Florida Everglades ecosystem. The objective of this study was to assess the dynamic changes in total phosphorus release (TPr) from ash or tissues of either cattail (Typha domingensis Pers.) or sawgrass (Cladium jamaicense Crantz) to water. Natural-dead (senesced-dead) and burning-dead (standing-dead due to a prescribed fire) cattail and sawgrass were collected from highly (H) and moderately (M) impacted zones in the Florida Everglades. This experiment was conducted by incubation and water-extraction of the materials in plastic bottles for 65 d at room temperature (24 +/- 1 degrees C). Results showed that 63 to 88%, 17 to 48%, 9 to 20%, and 13 to 28% of total P (TPp) were released as TPr from cattail and sawgrass ash, cattail tissues from the H zone, cattail tissues, and sawgrass tissues from the M zone, respectively. TPp means total P of plant tissues, whereas TPr is total P release from the tissues or ash. Most of the TPr was released within 24 h after burning. The quick release of TPr observed in this experiment may help explain the P surge in the surface water immediately following a fire in the marsh. These findings suggest that prescribed burning accelerates P release from cattail and sawgrass. They also imply that it is very important to keep the water stagnant in the first 24 h to maximize the benefits of a prescribed fire in the Everglades.

Hepatitis C virus infection of human hepatoma cell line 7721 in vitro

AIM: To establish a cell culture system with long-term replication of hepatitis C virus in vitro.

METHODS: Human hepatoma cell line 7721 was tested for its susceptibility to HCV by incubating with a serum from a patient with chronic hepatitis C. Cells and supernatant were harvested at various phases during the culturing periods. The presence of HCV RNA, the expression of HCV antigens in cells and/or supernatant were examined by RT-PCR, in situ hybridization and immunohisto-chemistry respectively.

RESULTS: The intracellular HCV RNA was first detected on d2 after infection and then could be intermittently detected in both cells and supernatant over a period of at least three months. The expression of HCV NS₃, CP₁₀ antigens could be observed in cells. The fresh cells could be infected by supernatant from cultured infected cells and the transmission of viral genome from HCV-infected 7721 cells to PBMCs was also observed.

CONCLUSION: The hepatoma line 7721 is not only susceptible to HCV but also supports its long-term replication in vitro.

Fluorescence spectral study of interaction of water-soluble metal complexes of Schiff-base and DNA

The fluorescence spectral characteristics and the interaction of several water-soluble metal complexes of Schiff-base with DNA are described. Among the complexes tested, Mn-Schiff-base bound to DNA showed a marked decrease in the fluorescence intensity with a blue shift of the excitation and emission peaks. Some hypochromism in the UV absorption spectra was also observed. KI quenching and competitive binding to DNA between Mn-Schiff-base and ethidium bromide (EB) were studied in connection with other experimental observations to show that the interactive model between Mn-Schiff-base and DNA is an intercalative one. The pH and salt effect on the fluorescence properties was also investigated. The linear relationship between F/F0 and the concentration of calf thymus DNA covers 3.0 x 10(-6)-2 x 10(-4) mol L-1, which can be utilized for determining traces of calf thymus DNA with a detection limit of 8.0 x 10(-7) mol L-1 in base pairs.

Renewable amperometric immunosensor for complement 3 assay based on the sol-gel technique

A renewable amperometric immunosensor based on the sol-gel technique has been constructed by dispersing graphite, complement 3 (C3) antiserum, and sol-gel at low temperature. The prepared immunosensor is rigid, porous, and has a renewable external surface. A competitive binding assay has been used to determine C3 in human serum with the aid of C3 labeled with horseradish peroxidase. The enzyme-labeled antigen can readily diffuse toward the encapsulated antibody, which retains its binding properties. The experimental conditions for the assay with the biocomposite, including the loading of C3 antiserum in the biocomposite, the amount of labeled C3 in incubation solution, incubation time, and temperature, have been optimized. Using C3 labeled with horseradish peroxidase, and o-AP as the substrate, amperometric detection at -150 mV (relative to the SCE) results in a linear detection range of 1.17-35.1 microg mL(-1), with a detection limit of 0.56 microg mL(-1). Serum samples have been assayed and the results demonstrate the feasibility of the proposed immunosensor for clinical analysis. The surface of the immunosensor can be renewed simply by polishing to obtain a fresh immunocomposite ready to use in a new competitive assay.

Renewable amperometric immunosensor for Schistosoma japonium antibody assay

A renewable amperometric immunosensor has been proposed for the determination of Schistosoma japonium antibody (SjAb) in rabbit serum. A paraffin-graphite-Schistosoma japonium antigen (SjAg) biocomposite, which needs no additional curing, was directly used to construct the immunosensors. The analytical sample containing the desired SjAb was mixed with SjAb labeled with horseradish peroxidase (HRP) to form the incubation solution for the competitive binding assay. Amperometry was used to determine the amount of HRP fixed on the sensor surface, which was related to the content of desired SjAb. Assay conditions were optimized, including the selection of substrate, the loading of SjAg in the biocomposite, the amount of labeled SjAb in the incubation solution, the incubation time, and the temperature. Using o-aminophenol (o-AP) as a substrate, amperometric detection at -200 mV (vs SCE) resulted in a pseudolinear detection range of about 0.36 to 14 microg/mL, with a detection limit of 0.36 microg/mL. Rabbit serum samples with varying infection degrees were analyzed, and the results demonstrated that the concentration that is detectable in this system meets the demands of clinical analyses. A new surface on the immunosensor for use in another competitive assay can be obtained by removing the original one and polishing the surface.

Renewable amperometric immunosensor based on paraffin-graphite-transferrin antiserum biocomposite for transferrin assay

A renewable electrochemical immunosensor was developed for the determination of transferrin in human serum. It is based on a paraffin-graphite-transferrin antiserum biocomposite, which needs no additional curing. A competitive binding assay was used to determine transferrin in human serum with the aid of transferrin labeled with horseradish peroxidase. The assay conditions were optimized, including the loading of transferrin antiserum in the biocomposite, the amount of labeled transferrin in the incubation solution, incubation time and temperature. Serum samples were analyzed and the results demonstrate that the concentration range of determination with this system meets the demands of clinical analysis. The surface of the immunosensor can be regenerated by simply polishing to obtain a fresh immunocomposite ready to be used in a new competitive assay.

Basic fibroblast growth factor enhanced LAK cell cytotoxicities against human bladder neoplasm cells

AIM

To study the effects of basic fibroblast growth factor (bFGF) on the proliferation of lymphokine-activated killer (LAK) cells from patients with bladder cancer and LAK cells cytolysis against bladder tumor cells.

METHODS

LAK cell proliferation was assayed in the presence of various concentrations of bFGF combined with interleukin-2 (IL-2) by cell count. Cytotoxicity of LAK cells against bladder cancer cell line EJ cells and bladder tumor cells (BTC) from patients was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays.

RESULTS

The proliferation of peripheral blood monocytes (PBMC) was inhibited by bFGF 5 micrograms.L-1. bFGF did not affect the stimulation of LAK cells induced by IL-2. The LAK cell numbers in the combination of IL-2 with bFGF were not significantly different compared with that treated with IL-2 alone. bFGF enhanced cytotoxicity of LAK cells against bladder cancer cell line EJ cells or BTC, respectively.

CONCLUSION

Although the proliferation of PBMC was inhibited by bFGF, bFGF increased LAK cell cytotoxicity against bladder neoplasm cells.

Modulating effect of mitomycin or cisplatin on lymphokine-activated killer cell proliferation and antitumor activity to bladder cancer cell lines in vitro

AIM

To study the effect of mitomycin (Mit) or cisplatin (Cis) on the proliferation of lymphokine-activated killer (LAK) cells in patients with transitional cell cancer of bladder and their cytolysis to bladder tumor cells.

METHODS

LAK cell proliferation was assayed in the presence of Mit or Cis by cell counting. Bladder cancer cell lines BIU-87 and EJ were cultured as target cells and cytotoxicity of LAK cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

The proliferation of LAK cells induced by recombinant interleukin-2 (IL-2) was inhibited by Cis in a concentration-dependent manner and was decreased to 55.3% at 100 mg.L-1 compared with control at 96 h. The enhanced growth of the LAK cells was observed with Mit 5-10 mg.L-1 from 48 to 96 h. Cis 10 mg.L-1 increased the cytotoxicity against BIU-87 and EJ cells.

CONCLUSION

Immunomodulatory effect of chemotherapeutic agents on LAK cell proliferation induced by IL-2 in patients with bladder cancer mainly depends on the drug itself.

Tretinoin or retinol enhancement of lymphokine-activated killer cell proliferation and cytotoxicity against human bladder cancer cells in vitro

AIM

To study the effect of tretinoin (Tre) or retinol (Ret) on the proliferation of lymphokine-activated killer (LAK) cells in patients with transitional cell cancer of bladder and their cytolysis to bladder tumor cells.

METHODS

LAK cell proliferation was assayed in the presence of either Tre or Ret by cell counting. Human transitional bladder cancer cell lines BIU-87, EJ, or bladder tumor cells (BTC) from patients with bladder cancer were used as target cells and cytotoxicity of LAK cells was determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

The proliferation of LAK cells induced by interleukin-2 (IL-2) was stimulated by Tre or Ret (10-100 nmol.L-1). The cytotoxicity of LAK cells against BIU-87, EJ cells, or BTC was enhanced by pretreatment of LAK cells with Tre or Ret 10-100 nmol.L-1.

CONCLUSION

Tre or Ret enhances the proliferation and cytotoxicity of LAK cells from patients with bladder cancer. Retinoids are potential in adoptive immunotherapy of bladder cancer.

Prevention of postischemic reperfusion damage on isolated working rat hearts by bopindolol and propranolol

Reperfusion after 30-min regional or global ischemia of the isolated working rat hearts did not restore the cardiac functions (as measured by cardiac output and power production), but exacerbated the existing damages. The lipid peroxidation product malondialdehyde (MDA) in the regional and global ischemic-reperfused myocardium increased by 37.6 and 45.2%, respectively. Bopindolol 0.1 mumol/L and propranolol 10 mumols/L protected the myocardium against the postischemic reperfusion damages, accelerated the recovery of cardiac functions during reperfusion and decreased the MDA content in the ischemic-reperfused myocardium. It is postulated that the prevention of cardiac cells from lipid peroxidation injury is related to the protection afforded by the drugs to the ischemic-reperfused hearts.

Effect of extract of Hirudo Medicinalis L. against adherence of calcium oxalate crystals to acid-injured bladder mucosa

The effect of extract of Hirudo Medicinalis L. on preventing the adhesion of calcium oxalate crystals to 0.1 M hydrochloric acid-injured bladder urothelium of the rat was studied. It was found that in this species the extract coated to the bladder mucosa after it was instilled into the chemically injured bladder; and the adhesion of calcium oxalate crystals was prevented. In regard to the anti-adhesion property the Hirudo extract appears more effective than heparin, a documented glycosaminoglycan.