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Biomedical subjects

S Liu

Publications and source records attributed to S Liu.

At least 631 records · Page 35Linked to original sources
PubMed1998

[Experimental studies on dynamic changes of circulating antigens of Schistosoma japonicum in infected rabbits].

AIM: To observe the dynamic changes and disappearance of three kinds of schistosome circulating antigens(CAgs) in infected rabbits before and after praziquantel treatment. METHODS: Dot-ELISA assays were developed by using 3 McAbs to determine the dynamic changes of the gut-associated antigen (GAA), membrane-associated antigen (MAA) and soluble egg antigen (SEA) respectively in sera of rabbits infected with S. japonicum. RESULTS: By the 4th week after infection 39% of the rabbits infected with S. japonicum were GAA positive and only 8.6% were MAA or SEA positive. All the infected rabbits becOme positive with GAA, MAA and SEA by the 8th week after infection. The titers of the GAA, MAA and SEA in sera of the infected rabbits reached their peaks by the 10th week after infection. Titers from rabbits of the untreated group rabbits remained high level until the 27th week after infection. SEA titers were found negative in 10% of the infected rabbits in the treatment group by the 6th week after treatment. The titers of GAA of, MAA' and SEA were found negative in 20%, 80% and 70% of the rabbits in the treatment group, respectively the 8th after treatment. GAA, MAA and SEA in sera except one of the treated rabbits were all negative by the 14th week after treatment. CONCLUSION: The determination of GAA is useful for the early diagnosis of schistosomiasis, while the determination of, MAA and SEA might be used for the efficacy evaluation.

Animals↗
PubMed1998

[Immunization of mice with native tropomyosins from Schistosoma japonicum and Oncomelania hupensis].

AIM: To study the protection against cercariae challenge in mice immunized with native tropomyosin (TM) antigens from Schistosoma japonicum (Chinese strain) and Oncomelania hupensis. METHODS: The native TM antigens were extracted from adult worms of S. japonicum (SjcTM) and head-pad of O. hupensis (OhTM), the purity and the molecular weight of these antigens were analysed by SDS-PAGE. Each C57BL/6 female mouse was immunized subcutaneously by injection of 5 micrograms SjcTM or 30 micrograms OhTM emulsified in an equal volume of Freuds adjuvant for three times. Control mice were injected only with adjuvant. All the mice were artificially challenged with cercariae of S. japonicum at five days after final injection. Six weeks after challenge, the mice were perfused, the worms and the eggs collected from the livers and the intestines of mice were counted. RESULTS: The prepared SjcTM and OhTM antigens were shown to be pure, the molecular weight being around 40 kDa. Compared with the control group, the worm reduction rates of SjcTM group and OhTM group were 21.1% and 28.2%, respectively; the egg reduction rates per worm pair in the tissues were 20.1% and 52.2% (liver), 32.8% and 28.1% (intestine), respectively; the matured egg reduction rates in the tissues were 25.9% and 46.8% (liver), 39.7% and 66.8%, respectively. CONCLUSION: SjcTM and OhTM antigens can be served as new candidates of vaccine against schistosomiasis japonica.

Animals↗
PubMed1998

[A study on processing of the root of Pueraria lobata (Willd.) ohwi by HPLC].

OBJECTIVE: To study the changes of active components in the root of Pueraria lobata after processing. METHOD: Using HPLC, with a C18 column, MeOH-H2O-CHCl3(25:75:1) as mobile phase, and flow rate 1 ml/min. RESULT: The Puerarin in different processed products of the drug is increased in content, but gets seriously destroyed if processed by carbonizing. CONCLUSION: The Puerarin content in the root of Pueraria lobata is affected by drug-processing.

Chromatography, High Pressure Liquid↗
PubMed1998

[Construction and screening of type 1 human immunodeficiency virus specific phage antibodies combinatorial library].

UNLABELLED: Human monoclonal antibodies to type 1 immunodeficiency virus (HIV-1) gp120 were generated from phage antibody combinatorial library. METHODS: The human immunoglobulin heavy chain Fd and light chain k genes were amplified by half-nested PCR from PBMC of patient infected with HIV. Phage antibody combinatorial library was constructed with the Fd and k chain genes using Pcomb3 as vector. The affinity selection and ELISA were adopted for generating specific phage antibodies. Partial DNA of a positive clone was sequenced and its soluble Fab was expressed in E coli. HIV-1 specific phage antibodies combinatorial library were constructed using the Fd and k genes and Pcomb3 vector. The library capacity was about 1.95 x 10(7). The specific phage antibodies were highly enriched after three rounds of biopanning selection against HIV-1 gp120 and 32% positive clones were detected by ELISA screening. DNA fragment coding for CH1 and CL derived from a positive clone was sequenced and its product was successfully expressed as soluble Fab which was specific for HIV-1 gp120. The HIV-1 specific phage antibody combinatorial library, and human monoclonal antibodies to HIV-1 gp120 have been used as tools for screening of neutralizing antibody to HIV-1, and the methods seem to be very crucial and applicable.

Amino Acid Sequence↗
PubMed1998

[Cloning and sequencing of adenovirus type 7 vaccine strain 76.5-87 mu fragment].

Adenovirus 7(Ad7) vaccine strain has been used more than 30 years in US army recruits for prevention of Ad7 infection and has been proven to be safe and effective. Recent years more attention has been paid to exploring the possibilities of using it for gene therapy or making recombinant vaccine. In order to construct adenovirus 7 vector, Ad 7 vaccine strain 76.5-87 mu fragment was cloned and sequenced. The fragment contains 3,557 bp which encodes 6 proteins of E3 region, namely 12.1 kD, 19.2 kD, 20.1 kD, 20.5 kD, 10.3 kD and partial of 15.2 kD. Nucleotide sequences of all these proteins show a high homology with the corresponding region of human adenovirus prototype strain Ad 7(Ad 7p) and Ad 7h(the homology of nucleotide sequence of the 6 proteins is more than 97.2%). The equivalent of ORF 16.1 kD in Ad7p and Ad7h was mutation due to a base pair deletion. The region corresponding to ORF 7.7 kD in Ad7p was missing in Ad7v due to a deletion. The results should be helpful to the construction of Ad7v vectors.

Adenovirus E3 Proteins↗
PubMed1998

[Construction of adenovirus type 7(vaccine strain) vector and expression of beta-galactosidase gene].

Human adenovirus type 7 DNA was extracted from purified virus cultured in WI-38 cells. The essential fragment (68-100 mu) of Ad7 DNA was used for constructing a non-defective Ad7 vector termed as pAd7 delta E3. The vector was characterized by a deletion at the E3 region that contains a multicloning site for the insertion of foreign genes. A helper-independent adenovirus type 7-beta-galactosidase recombinant was established. The recombinant contains the beta-galactosidase gene flanked by CMV early promoter and SV40 poly A signal. The constructed recombinant virus showed efficient capacity in expressing the foreign gene, beta-galactosidase.

Adenovirus E3 Proteins↗
PubMed1998

[Identificating of Actinomycetes producting activity of herbicide].

14 strains of Actinomycetes were isolated from soil samples collected in Yunnan, China. Experiments showed that they had activity of herbicide. In this paper, the morphological and chemotaxonomic characters of these strains were studied and they were identified as three genera of Actinomycetales respecitively, such as Streptomyces, Micromonospora and Nocardia.

Actinobacteria↗
PubMed1998

[Isolation and characterization of a insecticidal protein from Pseudomonas pseudoalcaligenes].

A insecticidal protein was purified by gel-filtration chromatography on Sephadex G-100 and anion-exchange chromatography on DEAE-Sephadex A-50 from the suspension of Pseudomonas pseudoalcaligenes culture. Certain biophysical and biochemical properties were also studied. The molecular weight of the subunit of the insecticidal protein is 25,100 and pI is 5.16. Amino acid composition analysis showed that it is an acidic protein.

Amino Acids↗
PubMed1998

[Tetracycline tracing of artificial bone composite with high biological induction in repairing bone defect].

The tetracycline tracing method was adopted to study the new bone formation at the early stage of two different composite artificial bones (HA-bBMP-Co and HA-Co)in repairing segmental bone defect in 8 rabbits. The results indicated that from the early stage even just one week after implantation, HA-bBMP-Co acted much faster than HA-Co did in inducing new bone formation, suggesting that HA-bBMP-Co be of good quality in ferms of histo-compatibility and osteoinduction.

Animals↗
PubMed1998

[Seeds collecting of Ephedra sinica and treatment before sown].

Seeds collecting of Ephedra sinica and treatment before sown were studied. These results indicated that time collecting seeds and treating such as threshing, washing, drying, storing at low temperature and immersing seeds with chemical were available measures. Which could supply a reference for the culture of E. sinica.

Desiccation↗
PubMed1998

[A preliminary report of the effect of levodopa and carbidopa for childhood amblyopia].

PURPOSE: To explore the short-term effect of levodopa and carbidopa in 36 children (4.5-14 years) with refractory amblyopia. METHODS: 36 cases of incurable childhood amblyopia treated with occlussion with visual acuity stably for 6 months were retreated by levodopa and carbidopa 1.5 mg/kg, 0.38 mg/kg respectively for 3 months. Visual acuity, fusional and stereoscopic function, retinal light sensitivity and scotomas were observed at 1 and 3 months after tablet taken. Medicine side effects were observed. RESULTS: At 3 months, the visual acuity of 88.89% eyes were improved(average 2.27 +/- 1.26 line), fusional and stereoscopic function were restored in 10 and 6 cases respectively. Retinal light sensitivity significantly increased, scotomas disappeared in 19 eyes and contracted in 6 eyes. The basic cure rate was 42.86% Less side effect were found. CONCLUSION: Average dose levels(1.5/0.38 mg/kg) of levodopa and carbidopa were an effective and secuity method to improve visual function of refractory childhood amblyopia.

Adolescent↗
PubMed1998

Unilateral acute idiopathic maculopathy.

PURPOSE: To discuss the fluorescein angiographic features and diagnosis as well as differential diagnosis. METHODS: In our hospital, we have found three cases of UAIM, one of them has eccentric maculopathy, another has papillitis, and the third associates with pregnancy. Each has characteristic clinical findings. We have made the diagnosis base on ophthalmoscopy and fluorescein angiography (FA). RESULTS: Three patients with UAIM have been experienced sudden unilateral decreased visual acuity. The significant changes on fundus are retinal pigment epithelium (RPE) thickening with neurosensory retinal detachment with in the macular area. FA showed early patchy hypofluorescence and hyperfluorescence at the level of the RPE. 'Bull's eye appearance may occur in the macular area after the acute stage of the disease. The clinical findings are similar to what the foreign report described. But there were no previous reports in China. CONCLUSION: We can establish the diagnosis on the base of clinical and fundus features associated with fluorescein angiographic findings. However, the etiology and pathology could not be identified. It required further research.

Acute Disease↗
PubMed1998

[Spectral interference correction for ICP-AES by factor analysis and a comparison with other methods].

Factor analysis method was used to correct spectral interference in inductively coupled plasma atomic emission spectrometry (ICP-AES) in the present work. The spectral overlap and structural background interferences were investigated and discussed with two real examples. Results show that the factor analysis is comparable to partial least squares (PLS) and the Kalman filtering in correcting the interferences.

English Abstract↗
PubMed1998

[Library search of UV spectra of organic environmental pollutants by artificial neural network].

In this paper, the artificial neural network (ANN) was applied to the library search of UV spectra of organic environmental pollutants. The optimization of network parameters was discussed and the effects of noise and impurity were investigated in detail. The use of derivative spectra for ANN library search was proposed to enhance the resolution of the UV spectra. This method could speed up the convergence of the network and could enhance the tolerance of impurity level, but was subject to noise comparing with the ANN using conventional UV spectra. Results show that the ANN is superior to the correlation coefficient method in resistance to noise and impurity.

Databases, Factual↗
PubMed1998

[A kinetic study of organic reaction by Kalman filter and spectrophotometry].

The Kalman filter-spectrometry was used to the study on the chemical dynamics of alpha-Oxo ketene cyclic dithioacetals. Results show that the method can effectively eliminate or reduce the intercomponent interferences in the simultaneous determination of all components. The method was successfully used to study the condensation reaction dynamics of 1-phenyl-2-(1,2-dithioethylene)methylene-1,3-dibutandione and m-nitrophenyl aldehyde.

English Abstract↗
PubMed1998

[Low temperature FTIR study of the structure of ruthenium polyhydrides].

A novel compound of Ru2H4 (CO) (PPh3)4 (A) is synthesized under hydrogen atmosphere. An in situ infrared apparatus which can be operated at liquid nitrogen temperarure is established. The structural conversion of RuH4 (PPh3)3 between dihydrogen and dihydride is observed firstly at room temperature. It is suggested that a fluxional molecule between terminal and bridged hydrogen appears in (A) with temperature changes. H2 molecule coordinated in ruthenium complex is rather easy to be substituted by CO, N2 and small organic molecule, this property is very important for activing molecular hydrogen and using in hydrogenation of unsaturated compounds.

English Abstract↗
PubMed1998

[Analysis of alpha-Oxo ketene cyclic dithioacetals compounds by using Kalman filtering and UV spectrophotometry].

The Kalman filtering and UV spectrophotometry have been used to analyte the alpha-Oxo ketene cyclic dithioacetal compounds in the present paper. The innovation sequence and concentration trends in the Kalman filtering process have been investigated, results show that the combination of the Kalman filtering and UV spectrophotometry is an applicable and reliable means in analysis of this kind of compounds.

English Abstract↗