Biomedical subjects

Tao Lin

Publications and source records attributed to Tao Lin.

36 records · Page 2Linked to original sources

PubMed2005

Enhanced immune response to gastric cancer specific antigen Peptide by coencapsulation with CpG oligodeoxynucleotides in nanoemulsion.

CpG oligodeoxynucleotides (CpG ODN) have been shown to have potent adjuvant activity for a wide range of antigens. Of particular interest is their improved activity when closely associated with the antigen. The purpose of this study is to construct a nanovaccine coencapsulated with a gastric cancer specific antigen MG7 mimotope peptide and adjuvant CpG ODN 1645 using new nanotechnology as nanoemulsion and evaluate its immunocompetence. Nanoemulsion vaccine was prepared using magnetic ultrasound methods. BALB/c mice were immunized and the in vivo effectiveness was evaluated using tumor challenge assay. It was shown that the tumor masses formed in the mice immunized with coencapsulated nanovaccine (0.0825 g) markedly smaller (P < 0.01) than those formed in the mice immunized with nanovaccine encapsulated with antigen peptide alone (0.4465 g). A tumor inhibiting rate as high as 82.5% of the coencapsulated nanovaccine was obtained, while nanovaccine encapsulated with peptide only could not achieve the same effect (28.5%) (P < 0.01). Enzyme-linked immunospot assay (ELISPOT) showed that immunization using MG7 mimotope peptide coencapsulated with CpG ODN within the same nanoemulsion enhanced the frequency of splenocytes secreting IFN-gamma significantly (P < 0.01) when compared with immunization using MG7 peptide encapsulated in nanoemulsion alone (197spots/1 x 10(6) vs. 73 spots/1 x 10(6)). Cellular ELISA indicated that serum titer of antibody against MG7-Ag was significantly higher (P < 0.01) in mice immunized with coencapsulation form nanovaccine (0.7884) than that in the group immunized with nanovaccine encapsulated with MG7 peptide alone (0.3616). Using intracellular flow cytometric analysis, it was found that the IFN-gamma response was contributed by CD4+ T-cells. Our experiments suggest that a vaccinal approach using nano-delivery system carrying in tumoral epitope and CpG ODN as adjuvant may have important implications for cancer therapy.

Animals↗

PubMed2005

Determination of norfloxacin by highly accurate nephelometric titration.

A highly accurate nephelometric titration for the determination of norfloxacin is presented. The titration operating conditions were studied and the solubility product constant of norfloxacin-tetraphenylboron precipitation was determined. The result of the titration is comparable to those of control experiments. The proposed method has been found to be accurate, precise, specific, and linear.

Nephelometry and Turbidimetry↗

PubMed2005

Programmed humidifying in drug stability experiments.

The stability of penicillin potassium, as a solid state model, was investigated by a programmed humidity and temperature controlled method. An optimization calculational approach to data handling is suggested. The stability of drugs which are unstable to both heat and moisture could be studied by a single pair of experiments, one with programmed humidity control and one non-isothermal, rather than many standard isothermal studies, each at constant relative humidity. The controlling system, based on a pocket computer, was found to be accurate and reliable. The results indicated that the kinetic parameters obtained were comparable to those from isothermal studies.

Drug Stability↗

PubMed2005

'Candidatus Borrelia texasensis', from the American dog tick Dermacentor variabilis.

TXW-1, a Borrelia strain isolated in March 1998 from an adult male Dermacentor variabilis tick feeding on a coyote from Webb county, Texas, USA, was characterized by using randomly amplified polymorphic DNA (RAPD) analysis, RFLP and sequence analysis of flaB and rrs (16S rRNA gene), DNA-DNA hybridization analysis, SDS-PAGE and Western blotting with mAbs. It shows different banding patterns in RFLP analysis of flaB and forms distinct branches in phylogenetic analysis derived from flaB and rrs genes. It differs from other borreliae based on the banding patterns obtained by RAPD analysis. This strain contains a small, 38-kDa endoflagellar protein. DNA-DNA hybridization experiments revealed that the levels of DNA reassociation between TXW-1 and previously described relapsing fever borreliae were 38.64 % (Borrelia turicatae), 38.40 % (Borrelia parkeri), 7.39 % (Borrelia hermsii) and 18.30 % (Borrelia coriaceae). However, the level of DNA relatedness between B. parkeri and B. turicatae was 78.78 %. Sequence analyses of flaB and rrs genes indicate that the similarities of nucleotide sequences among TXW-1 and B. turicatae or B. parkeri are less than that between B. turicatae and B. parkeri, and that the genetic distances among TXW-1 and B. turicatae or B. parkeri are greater than that between B. turicatae and B. parkeri. TXW-1 lacks an ospC gene. Electron microscope observations showed that this spirochaete had different morphological structures compared to previously described relapsing fever borreliae. All the results obtained from the above-mentioned analyses indicate that TXW-1 is different from other described Borrelia species and that it represents a novel species of Borrelia. We have been unable to revive frozen cultures and so can not meet the requirements of the Bacteriological Code to deposit viable type material at two different culture collections. Therefore we use the Candidatus designation; based on these results, the species 'Candidatus Borrelia texasensis' is proposed.

Animals↗

PubMed2005

Immune responses to foot-and-mouth disease DNA vaccines can be enhanced by coinjection with the Isatis indigotica extract.

The Isatis indigotica extract is widely used in clinical practice for the treatment of influenza, epidemic hepatitis, epidemic encephalitis B etc. The goal of this study was to investigate whether coinjection of the Isatis indigotica extract with foot-and-mouth disease virus (FMDV) DNA vaccine could increase the protective immune response. Mice were vaccinated twice with either FMDV DNA vaccine plus the Isatis indigotica extract or DNA vaccine alone. Compared with the group of DNA vaccine alone, in the group that received DNA vaccine plus the Isatis indigotica extract was observed a significant increase in not only FMDV-specific antibody response but also T cell proliferation assay. All swine immunized with either FMDV DNA vaccine plus the Isatis indigotica extract or DNA vaccine alone were partially protected from FMDV challenge, but the signs of DNA vaccine plus the Isatis indigotica extract group were less severe than that of DNA vaccine alone. Coinjection of the Isatis indigotica extract with DNA vaccine has adjuvant effect on the immune response against viral pathogens and its application provides an effective strategy to improve the efficacy of DNA vaccines.

Adjuvants, Immunologic↗

PubMed2005

[CT analysis of 69 patients with nasopharyngeal carcinoma invading the Cranio-maxillofacial structures].

PURPOSE: To analyze the characteristics of involvement of surrounding tissues in nasopharyngeal carcinoma(NPC). METHODS: CT images of 69 cases with preradiotherapeutic nasopharyngeal carcinoma were analyzed to calculate the rates of anterior spread(including pterygoid plates,pterygopalatine fossa, maxillary sinus, ethmoidal sinus, nasal cavity), lateral spread(including palatal muscle, parapharyngeal space, carotid sheath and infratemporal fossa), medial spread(including pharyngeal cavity, the contralateral side of the nasopharynx), posterior spread(including prevertebral muscle, cervical vertebra and clivus), superior spread(including sphenoidal sinus,foramen lacerum, foramen ovale, greater wing of sphenoid bone, petrous apex and intracranial region), inferior spread(including oropharynx, parapharyngeal space, soft palate, hard palate) respectively. RESULTS: 18 cases of in this series had anterior spread(26.1%); 53 had lateral spread(76.8%); 31 had medial spread(44.9%); 32 had posterior spread(46.4%); 14 had superior spread(20.3%); 29 had inferior spread(42.0%). CONCLUSIONS: Lateral spread is the most common spread direction in nasopharyngeal carcinoma, followed by posterior spread, median spread, inferior spread, anterior spread, superior spread in turn.

Carcinoma↗

PubMed2004

Differentiation of group VIII Spiroplasma strains with sequences of the 16S-23S rDNA intergenic spacer region.

Spiroplasma species (Mollicutes: Spiroplasmataceae) are associated with a wide variety of insects, and serology has classified this genus into 34 groups, 3 with subgroups. The 16S rRNA gene has been used for phylogenetic analysis of spiroplasmas, but this approach is uninformative for group VIII because the serologically distinct subgroups generally have similarity coefficients >0.990. Therefore, we investigated the utility of the 16S-23S rRNA spacer region as a means to differentiate closely related subgroups or strains. We generated intergenic sequences and detailed serological profiles for 8 group VIII Spiroplasma strains. Sequence analyses using Maximum Parsimony, Neighbor Joining, and Maximum Likelihood placed the strains into 2 clades. One clade consisted of strains BARC 2649 and GSU5367. The other clade was divided into clusters containing representatives of the 3 designated group VIII subgroups (EA-1, DF-1, and TAAS-1) and 3 previously unclassified strains. The stability of the positions of the strains in various analytical models and the ability to provide robust support for groupings tentatively supported by serology indicates that the 16S-23S intergenic rDNA sequence will prove useful in intragroup analysis of group VIII spiroplasmas.

DNA, Bacterial↗

PubMed2004

Molecular characterization of Borrelia isolates from ticks and mammals from the southern United States.

Fifty Borrelia isolates from ticks and rodents from several geographic regions of the southern United States were analyzed by genomic macrorestriction analysis. Significant genetic diversity was observed among them. These isolates segregated into 4 major clusters and 10 subclusters, which are correlated with the genospecies distribution. Nineteen pulsed-field gel electrophoresis (PFGE) types were recognized among the isolates. The genospecies Borrelia andersonii and Borrelia bissettii consisted of 5 and 2 subclusters, respectively. Two subclusters comprised the Borrelia burgdorferi sensu stricto (s. s.) strains. These results indicated that PFGE is a suitable molecular typing method for B. burgdorferi at both the genospecies and strain levels. Seventeen representative isolates from different PFGE groups were analyzed by restriction fragment length polymorphism (RFLP) and sequence analysis of flaB. Twenty-three AluI, 3 CelII, and 11 DdeI RFLP patterns were found among strains from the B. burgdorferi sensu lato (s. l.) complex and the relapsing fever borreliae complex. Three genospecies in the B. burgdorferi s. l. complex and 1 species in the relapsing fever borreliae complex were recognized. Phylogenetic analysis based on nucleotide sequences of flaB indicated that all the Borrelia strains analyzed here could be divided into 2 parts, i.e., B. burgdorferi s. l. complex and the relapsing fever borreliae complex. The flaB appears to be a useful target gene to screen and identify strains from both B. burgdorferi s. l. and relapsing fever borreliae complexes.

Animals↗

PubMed2004

[A new rat model of transplant kidney-sclerosis accelerated by prolonged cold ischemia time].

OBJECTIVE: To establish an accelerated animal model of the chronic renal allograft dysfunction in rat. METHODS: Kidney transplantation was performed from SD to Wistar strain (allogeneic) according to the procedure of Kamada with some modification. Before the transplantation, the kidney was preserved in 0-4 degrees C heparin sodium chloride solution for prolonging the one hour. The serum creatinine level and pathological change of transplant kidney were observed in the 2nd, 4th, 6th, 8th and 12th weeks post-transplantation. RESULTS: After transplantation, the serum creatinine level of recipient rats obviously increased in the 6th week and the pathologic changes of chronic nephropathy evidently appeared in the 8th week when compared to those of the control group with non-reinforcement I/R injury; a statistically significant difference was noted. CONCLUSION: It is simple and feasible to establish a rat model of (SD-->Wistar) transplant kidney-sclerosis accelerated by prolonging I/R injury.

Animals↗

PubMed2004

[Influence of illuminance on the photo-reaction rate order of nitrofurazone solution].

OBJECTIVE: To explore the relationship between the illuminance and the observed order of reaction of photodegradation of nitrofurazone solution. METHODS: Studying the observed order of reaction of photodegradation of nitrofurazone solution exposed to light with three illuminance values at three concentration values respectively. RESULTS: The observed order of reaction of photodegradation increased with the decrease of concentration when the illuminance kept constant and, on the other hand, the observed order increased with the increase of illuminance when the concentration kept constant. CONCLUSION: The observed order of reaction of photodegradation of nitrofurazone solution depends on both the concentration of the drug and the illuminance of the incident light.

Drug Stability↗

PubMed2004

Full-scale study of removal effect on Cyclops of zooplankton with chlorine dioxide.

Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.

Animals↗

PubMed2004

Influence of light and temperature on the stability of procaine hydrochloride injection.

AIM: To study the influence of light and heat on the stability of procaine hydrochloride injection. METHODS: Accelerated tests upon exposure to light at high temperatures were employed. RESULTS: In experiments with either isothermal heating or exposure to light at high temperatures, the drug degradation rate obeys first-order kinetics. The total rate constant, ktotal, caused by both light and heat can be divided into two parts: ktotal = kdark + klight, where kdark and klight are the rate constants caused by heat and light, respectively. The klight can be expressed as klight = Alight x E x exp(-Ea,light/RT). Where E is the illuminance of light, Alight is an experimental constant related to light sources, and Ea,light is an experimental constant. CONCLUSION: Because the form of klight is similar to the Arrhenius equation, it is suggested that Ea,light might be the observed activation energy of the rate-determining step of the subsequent processes of the photochemical reaction. This viewpoint is supported by the fact that the Ea,light is independent of light sources.

Drug Stability↗

PubMed2004

[Effect of programmed humidification and temperature on drug stability].

AIM: To simplify the study on the effect of relative humidity and temperature on drug stability. METHODS: The stability of penicillin potassium as a model was studied with programmed humidifying and heating. RESULTS: Results of our programmed humidifying and heating experiments are comparable to those of traditional experiment at constant humidity and temperature. CONCLUSION: Programmed humidifying and heating experiments are applicable to drug stability study.

Drug Stability↗

PubMed2003

Comparative analysis of Borrelia isolates from southeastern USA based on randomly amplified polymorphic DNA fingerprint and 16S ribosomal gene sequence analyses.

Fifty-three southern USA Borrelia isolates were characterized using randomly amplified polymorphic DNA fingerprinting analysis (RAPD). Twenty-nine types were recognized among 37 B. andersonii strains, seven types among eight B. bissettii strains, and seven types among seven B. burgdorferi sensu stricto strains. Strain TXW-1 formed a separate RAPD type. Nearly complete sequences of the rrs genes from 17 representative southern Borrelia were determined. The similarity values were found to be 96-100% within the B. burgdorferi sensu lato (s.l.) complex, 94-99% among the relapsing fever borreliae, and 93-99% between the two complexes. Phylogenetic analysis indicated that all the Borrelia strains we analyzed could be divided into two parts: the B. burgdorferi s.l. complex and the relapsing fever borreliae complex. TXW-1 segregated with the North American relapsing fever borreliae and formed a separate subbranch.

Animals↗

PubMed2003

Screening and identification of mimotope of gastric cancer associated antigen MGb1-Ag.

AIM: Using a monoclonal antibody against gastric cancer antigen named MGb1 to screen a phage-displayed random peptide library fused with coat protein pIII in order to get some information on mimotopes. METHODS: Through affinity enrichment and ELISA screening, positive clones of phages were amplified. 10 phage clones were selected after three rounds of biopanning and the ability of specific binding of the positive phage clones to MGb1-Ab were detected by ELISA assay (DNA sequencing was performed and the amino acid sequences were deduced) By blocking test, specificity of the mimic phage epitopes was identified. RESULTS: There were approximately 200 times of enrichment about the titer of bound phages after three rounds of biopanning procedures. DNA of 10 phage clones after the third biopanning was assayed and the result showed that the positive clones had a specific binding activity to MGb1-Ab and a weak ability of binding to control mAb or to mouse IgG. DNA sequencing of 10 phage clones was performed and the amino acid sequences were deduced. According to the homology of the amino acid sequences of the displayed peptides, most of the phage clones had motifs of H(x)Q or L(x)S. And these 10 phage clones could also partly inhibit the binding of MGb1-Ab to gastric cancer cell KATO-III. The percentage of blocking was from (21.0+/-1.6) % to (39.0+/-2.7) %. CONCLUSION: Motifs of H(x)Q and L(x)S selected and identified show a high homology in the mimic epitopes of gastric cancer associated antigen. There may be one or more clones which can act as candidates of tumor vaccines.

Animals↗

PubMed2003

[Study on the clinical use of alpha-fetoprotein (AFP) colloidal gold diagnostic strip].

OBJECTIVE: To test the sensitivity and specificity of alpha-fetoprotein (AFP) colloidal gold diagnostic strip as compared with RIA-AFP diagnostic kit. METHODS: Double blind method was used to test sera from 426 healthy people and 1567 patients selected in two general hospitals and a cancer hospital. Each serum was measured by RIA-AFP and AFP colloidal gold diagnostic strip on the same day. RIA-AFP diagnostic results was identified as true positive or negative. RESULTS: Among 426 healthy people, all the RIA-AFP test showed negative result (serum AFP concentration less than 25 IU/ml), but the AFP colloidal gold diagnostic strip had 1.88% false positive. When comparing the result from 1567 patients measured by RIA-AFP, the sensitivity and specificity of AFP colloidal gold diagnostic strip were 99.3%, and 97.2%, respectively. The crude correspondence rate between the two diagnostic regents was 97.6%. CONCLUSION: AFP colloidal gold diagnostic strip showed very good result and could be used as a screening diagnostic kit in clinic and hospital settings.

Biomarkers, Tumor↗

PubMed2002

Genetic diversity of the outer surface protein C gene of southern Borrelia isolates and its possible epidemiological, clinical, and pathogenetic implications.

The ospC genes of 20 southern Borrelia strains were sequenced. The strains consisted of B. burgdorferi sensu stricto, B. andersonii, B. bissettii, one undescribed genospecies, MI-8, and one probably new Borrelia species, TXW-1. A high degree of similarity exists between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Lateral transfers of the ospC gene probably occurred between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Internal gene recombination appears to occur among them. The highest degree of genetic diversity among them was observed in the two variable domains (V1 and V2), semivariable domain (SV), and the species-specific epitopes (between amino acids 28 and 31). Differences in ospC sequences among southern strains reflect diversity at the strain and genospecies levels. MI-8, which was recognized as an undescribed genospecies in our previous reports, remains distinguishable in our current analysis of ospC genes and is distinct from B. burgdorferi sensu stricto. Interestingly, another undescribed southern isolate, TXW-1, was not amplified under various PCR conditions. Compared to European B. burgdorferi sensu stricto strains, American B. burgdorferi sensu stricto strains show greater genetic heterogeneity. Southern B. burgdorferi sensu stricto, B. andersonii, and B. bissettii isolates were intermixed with each other in the phylogenetic trees. In the derived trees in our work, at least one southeastern strain of B. burgdorferi, MI-2, most closely aligns with a so-called invasive cluster that possesses many proven human-invasive strains. Transmission experiments show that MI-2 and the strains in this group of southern spirochetes are able to infect mice and hamsters and that the typical vector of Lyme disease, Ixodes scapularis, can acquire the spirochetes from infected mammals. Currently, strain MI-2 appears to be the only southern isolate among the 20 we analyzed that clusters with an OspC invasive group and thus might be invasive for humans.

Amino Acid Sequence↗

PubMed2002

[Effect of light and heat on the stability of furacilin aqueous solution].

AIM: To study the effect of both light and heat on the stability of furacilin aqueous solution and the probability of substituting for isothermal accelerated tests by nonisothermal accelerated tests upon exposure to light at high temperatures. METHODS: The isothermal and nonisothermal accelerated tests were employed. The accelerated tests were proceeded in the dark and exposed to light at high temperature. Tungsten, ultraviolet and fluorescent lamps were employed in exposure tests. RESULTS: The degradation of furacilin aqueous solution in isothermal heating experiments or the exposure experiments to light at high temperatures obeys zero-order kinetics. The total degradation rate constant k caused by both light and heat can be divided into two parts: k = kdark + klight, where kdark and klight are the degradation rate constant caused by heat and light, respectively. The klight can be expressed as klight = Alight.exp(-Ea,light/RT).E, where E is the illuminance of light; Alight and Ea,light are both experimental constants. The parameters obtained in nonisothermal accelerated tests were comparable to those obtained in classic isothermal accelerated tests. CONCLUSION: Nonisothermal accelerated tests may substitute for isothermal accelerated tests during the study of the effects of both light and heat on the stability of drugs, in order to save time, labor and drugs.

Anti-Infective Agents, Local↗