Biomedical subjects

Jun Yin

Publications and source records attributed to Jun Yin.

At least 55 records · Page 3Linked to original sources

PubMed2004

Effects of periods of nonuse and fluctuating ammonia concentration on biofilter performance.

A systematic study on the transient behavior of odor treatment using biofilters is described. The biofilters were exposed to variations in contaminant loading and periods of nonuse. Two bench-scale biofilters with different filter media were used. Mixtures of compost/perlite (5:1) and dry sludge/granular active carbon (5:1) were used as filter media. Ammonia (NH3), one of the main malodorous gases, was used as the target compound. The response of each biofilter to variations in contaminant mass loading, periodic nonuse, water content, and inlet concentration pulse was studied. The nonuse period comprised of two stages: the "idle phase" when no air was passing through the biofilters, and the "no-contaminant-loading phase" when only humidified air was passing through the biofilters. Concentration spike was applied to study the effects of shock loading on the biofilter performance. Biofilters responded effectively to NH3 concentration variations and shock loading by rapidly recovering to the original removal rates within 6-12h. The results indicated re-acclimation times ranged from several hours to longer than a day. Longer idle phase produced longer re-acclimation periods than periods of no contaminant loading. When the media was dried during the biofiltration process, elimination capacity dropped accordingly for both biofilters. After 24 h of drying, the biofilter experiment could be restarted and run for a few days for recovering.

Ammonia↗

PubMed2004

Antiosteoporotic activity of the water extract of Dioscorea spongiosa.

After 60 MeOH and water extracts of natural crude drugs were screened for their ability to stimulate osteoblast proliferation, four MeOH extracts (Cynomorium songaricum, Drynaria fortunei, Lycium chinense, Rehmannia glutinosa) and seven water extracts (Cornus officinalis, Dendrobium nobile, Dioscorea spongiosa, Drynaria fortunei, Eucommia ulmoides, Lycium chinensis, Viscum coloratum) showed that potent activities were evaluated for inhibition of osteoclast formation. The results indicated that the water extract of D. spongiosa not only showed the strongest stimulation of osteoblast proliferation but also possessed potent inhibitory activity aganist osteoclast formation, whereas it showed lower cytotoxicity in osteoblast and bone marrow cells. A further in vivo experiment determined the antiosteoporotic activity of this extract, in which it inhibited the decrease in cancellous bone mineral content, cancellous bone mineral density, and cortical bone mineral content of the proximal tibia in ovariectomized rats.

Animals↗

PubMed2004

Polymorphisms of the coagulation factor VII gene and its plasma levels in relation to acute cerebral infarction differences in allelic frequencies between Chinese Han and European populations.

BACKGROUND: Coagulation factor VII (FVII) levels in plasma are usually related to ischemic heart disease (IHD) and cerebral infarction shares many of the risk factors related to IHD. Is there any relationship between factor VII and cerebral infarction? We investigated the relationship between FVII and acute cerebral infarction and reported genotype frequencies and allelic frequencies of FVII gene polymorphisms in the Chinese Han population. METHODS: We recruited 62 patients with acute cerebral infarction confirmed by magnetic resonance imaging (MRI) from Ruijin Hospital, and 149 age-matched patients clinically free of vascular disease to act as controls. All of them were unrelated, and were from the Chinese Han population. FVII coagulant activity (FVIIc) was determined using an clotting assay, activated FVII (FVIIa) and FVII Ag were assayed using enzyme immunoassay kits. The FVII gene polymorphisms to be detected included-401G/T, -402G/A, 5'F7A1/A2, IVS7 and R353Q. 5'F7 and IVS7 were revealed by means of a PCR and direct agarose gel electrophoresis. The rest were examined by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The results showed that FVIIc, FVIIAg and FVIIa were higher in the acute cerebral infarction group than in the control group (P < 0.01, P < 0.05, P < 0.05, respectively). There were no significant differences in the genotype frequencies of FVII gene polymorphisms between the two groups. The allelic frequencies in the Chinese Han population were as follows: -401G/T (96.64/3.36), -402G/A (52.01/47.99), 5'F7A1/A2 (96.64/3.36), IVS7 H5/H6/H7/H8 (0.34/52.35/46.98/0.34) and R353Q (95.64/4.36). There were significant differences (P < 0.01, P < 0.001, P < 0.001, P < 0.001, P < 0.001, respectively) in these allelic frequencies between the Chinese Han and European populations. CONCLUSIONS: The results indicate that increased plasma FVII levels may contribute to thrombosis in cerebral infarction. And there was no significant difference in genotype frequencies of these five FVII gene polymorphisms between the acute cerebral infarction and control groups. Moreover, these results showed that the frequencies of protective allele, including -401T, 5'F7 A2 and 353Q were lower, but that -402A, which was previously found to be associated with increased plasma FVII levels, is higher in Chinese Han population.

Acute Disease↗

PubMed2004

[Construction of human phage-displayed scFv library and selection of the ScFv against rabies virus].

AIM: To construct a human phage displayed single chain Fv antibody (scFv) library and screen specific scFv against rabies virus. METHODS: Using a phage-display technique, IgVH and IgVL genes were cloned from peripheral blood lymphocytes from three donors immunized with the WISTAR PM strain vaccine. Genes encoding scFv fragments were constructed by random linkage of VH gene and VL gene by SOE PCR, and then the constructed scFv genes were cloned into phagemid vector and transfected into E. coli TG1. The recombinant phages were screened by four rounds of panning with rabies virus vaccine. The positive recombinant phages were sequenced and antigen-binding activity of recombinant scFv was detected by competition ELISA. RESULTS: A human phage-displayed scFv library with about 7 x 10(8) sink size was constructed. A new human scFv was selected, which bound specifically to rabies virus and had higher affinity. CONCLUSION: The results lay a solid foundation for preparation of human engineering antibody to rabies virus reported herein with higher affinity.

Amino Acid Sequence↗

PubMed2004

[Cloning and analysis of six full-length cDNA similar to sheep KAP6-1 from cashmere goat].

Cashmere is the fiber of kings, produced from the cashmere goat (Capra hircus). Cashmere fabric has little squama. Due to its lightness cashmere feels smooth and silky. An intriguing feature of cashmere structure is multiplicity of the hair keratin proteins with distinctive amino acid compositions. To study the role and regulation of one of these keratins, we used the SMART ( switching mechanism at 5' end of RNA transcript) technology to construct a cDNA library of skin tissue from an Inner Mongolia male cashmere goat. A total of 636 cDNA sequences were obtained by randomly sequenced from 5' of cDNA library. Sequence comparison with the GenBank database confirmed that there are 41 sequences showed high nucleotide sequence identity in the coding region with sheep keratin associated protein 6-1 (KAP6-1). They represent six different cDNAs (The accession numbers in GenBenk are AY310749, AY310750, AY310751, AY310752, AY310753 and AY310754, respectively). They are full-length cDNAs according to the known KAP6-1 genomic gene sequences of sheep. From the nucleotide sequences the open reading frames were identified, that encoded six basic proteins of 82, 84, 71, 71, 83, 83 amino acids, respectively, with a combined glycine and tyrosine content of about 60%. Compared analysis showed that the KAPs from goats shared more than 55.4% identities in nucleotide sequences and more than 79.8% identities in amino acid sequences with each other, and shared highest identities (81.9% approximately 98.8%) with KAP6-1 from sheep. The KAP6s from different animal species shared more than 50% identities in amino acid sequences with each other.

Amino Acid Sequence↗

PubMed2004

Biological removal of air loaded with a hydrogen sulfide and ammonia mixture.

The nuisance impact of air pollutant emissions from wastewater pumping stations is a major issue of concern to China. Hydrogen sulfide and ammonia are commonly the primary odor and are important targets for removal. An alternative control technology, biofiltration, was studied. The aim of this study is to investigate the potential of unit systems packed with compost in terms of ammonia and hydrogen sulfide emissions treatment, and to establish optimal operating conditions for a full-scale conceptual design. The laboratory scale biofilter packed with compost was continuously supplied with hydrogen sulfide and ammonia gas mixtures. A volumetric load of less than 150 gH2S/(m3 x d) and 230 gNH3/(m3 x d) was applied for about fifteen weeks. Hydrogen sulfide and ammonia elimination occurred in the biofilter simultaneously. The removal efficiency, removal capacity and removal kinetics in the biofilter were studied. The hydrogen sulfide removal efficiency reached was very high above 99%, and ammonia removal efficiency was about 80%. Hydrogen sulfide was oxidized into sulphate. The ammonia oxidation products were nitrite and nitrate. Ammonia in the biofilter was mainly removed by adsorption onto the carrier material and by absorption into the water fraction of the carrier material. High percentages of hydrogen sulfide or ammonia were oxidized in the first section of the column. Through kinetics analysis, the presence of ammonia did not hinder the hydrogen sulfide removal. According to the relationship between pressure drop and gas velocity for the biofilter and Reynolds number, non-Darcy flow can be assumed to represent the flow in the medium.

Air Pollutants↗

PubMed2004

[Non-viral vector mediating human coagulation factor VIII gene expression in mouse 32D cell line].

To investigate the non-viral vector mediating human coagulation factor VIII gene expression in mouse 32D cell line, a recombinant plasmid vector, pRC/RSV-hFVIIIBDcDNA, was constructed by cloning B-domain-deleted (Delta760aa-1639aa) human factor VIII cDNA (hFVIIIBDcDNA) into plasmid vector, pRC/RSV. The plasmid RC/RSV-hFVIIIBDcDNA was then transfected by means of SuperFect Transfection Reagent into mouse 32D cell line. After screening with G418, the procoagulant activity (hFVIII:C) and antigen (hFVIII:Ag) of human factor VIII in the culture medium were detected using one-stage method and ELISA, respectively. Furthermore, RT-PCR was performed to observe the transcription of hFVIIIBDcDNA. The results showed that human coagulation factor VIII protein existed in culture medium with hFVIII:C up to 2.01 U/(10(6) cell x 24 hours) and hFVIII:Ag to 450.08 ng/(10(6) cell x 24 hours). RT-PCR displayed mRNA of hFVIIIBDcDNA in 32D cells. It is concluded that the recombinant plasmid RC/RSV-hFVIIIBDcDNA can successfully express human FVIII in mouse 32D cell line, and hFVIII expressed in vitro presents the similar coagulant activity to the native hFVIII existing in normal human plasma.

Animals↗

PubMed2004

[Preliminary application of PCR-DGGE to analyzing microbial diversity in biofilters treating air loaded with ammonia].

As a new DNA fingerprinting technique, denaturing gradient gel electrophoresis (DGGE) can be used to analyze the microbial diversity in different environmental samples. Three biofilters treating air loaded with ammonia will be studied with respect to microbial diversity by applying cultivation-independent molecular methods DGGE. The principal objectives of this paper include the development and application of a suitable set of molecular tools to deliver information about the possible microbial community changes within carriers during treatment of ammonia-contaminated gas. Carriers were sampled at different time during operation of biofilters. After extraction and purification of the genomic DNA, the 16S rRNA genes (V3 region) were amplified by using the specific primers. These amplified DNA fragments were then separated by paralleled DGGE. The profile of DGGE showed that the same carrier at different time had the different bands' patterns. The structural diversity of the microbial community was examined by the Shannon index of general diversity H. Shannon indexes of three kinds of carriers all showed a decrease with time, which had a similar trend to NH3 removal efficiency.

Air Pollutants↗

PubMed2004

[Modification and high level expression of protective antigen fragment of botulinum neurotoxin serotype A].

Designed a pair of primers through modifying N-terminal bases (5bps) of gene after ATG but not changing amino acid, and amplified a smaller mutated gene sequnce (468bp) containing two protective antigenic determinants from pBlue-BoNTaHc, N-terminal codon of mutated gene fragment is changed from low to high frenqence in E. coli. Mutated gene was ligated into pGEM-T vector and sequenced, then, cloned into a expression plasmid pBV220. As a result, cloned gene was expressed in insoluble form by temperature inducing (from 30 degrees C to 42 degrees C) in E. coli. Expression product is 40% of total proteins and is of specific binding activity to antibody in ELISA. The successful modification and high level expression of protective fragment of botulinum neurotoxin serotype A(BoNTaHc468) gene is conducive to further study on antitoxin and vaccine.

Bacterial Vaccines↗

PubMed2004

[Preparation of alpha-toxin's protective antigen of clostridium perfringens type A and research for its primary immunological protective function].

Induced by 42 degrees C, the recombinant engineering bacterial pBV/cpa408 was highly expressed. After having been pelleted by 80% (NH4)2 SO4 and dialysised, the expressed protein was isolated and purified by the gel filtration choromatography. Then according to an amount of 1.0 mg/kg, the Kunming Mice (body weighted 18g) were immuned with the purified protein by intraperitoneal inoculation. One week after the first enhanced immunization, the Kunming Mice were attacked with an amount of 1.0MLD alpha-toxin, in which the eight mice immuned all survive and the control group all died. During the period of immunization, the titre of the mouse's serum antibody was measured by ELISA. One week after the first immunization, the titre of the mice's serum antibody was 1:800, but that of one week after the first enhanced immunization reached to 1:6400.

Animals↗

PubMed2003

[Molecular mechanisms of two novel mutations of factor XIII gene resulting in hereditary coagulation deficiency].

OBJECTIVE: To investigate the mechanisms of two novel missense mutations of factor XIIIA subunit gene (Arg77-->Cys,Ser413-->Trp) in the pathogenesis of hereditary factor XIII deficiency. METHODS: Site-directed mutagenesis was conducted to obtain 2 mutant human XIII A recombinant plasmids, mut-PCI/FXIIIA. Normal wild type factor XIII A recombinant plasmid, wt-PCI/FXIIIA, and mut-PCI/FXIIIA, were transfected into cultured COS7 cells line, renal fibroid cell of African green monkey using Superfect reagent respectively, The expression levels of DNA, RNA and protein of human factor XIII, both wild type and mutant, were detected by PCR, RT-PCR and Western blotting. Pulse-chase experiment was used to look into the changing of factor XIII A in the cytoplasm. Factor XIIIA activity was assayed by Biotin-pentylamine incorporation technique. RESULTS: The mRNA levels of the two mutants in transfected cells were similar to that of the wild type factor XIIIA. But the amount of mutant factor XIIIA protein and its activity in cells decreased markedly, even disappeared. Pulse-chase experiment revealed that at the two mutants existed chase time 0.5 h and 1 h considerable amounts in cells and then disappeared rapidly later. CONCLUSION: The 2 mutations of the factor XIIIA cause the instability, degradation, and rapid disappearance of FXIIIA in cytoplasm, thus resulting in hereditary factor XIII deficiency.

Animals↗

PubMed2003

Formation of whisker-related principal sensory nucleus-based lemniscal pathway requires a paired homeodomain transcription factor, Drg11.

Little is known about the molecular mechanisms underlying the formation of the principal sensory nucleus (PrV) of the trigeminal nerve, a major relay station for somatotopic pattern formation in the trigeminal system. Here, we show that mice lacking Drg11, a homeodomain transcription factor, exhibit defects within the PrV, which include an aberrant distribution of Drg11-/- cells, altered expression of a molecular marker, unusual projections of primary afferents from trigeminal ganglion cells, and, subsequently, increased cell death. In addition, surviving PrV cells exhibit delayed and more spatially restricted ascending projections to the ventral posterior medial nucleus of the thalamus (VPm). These early embryonic abnormalities in the PrV lead to the failure to develop whisker-related patterns in the PrV, VPm, and somatosensory cortex. By contrast, somatotopic patterns exist in the spinal trigeminal subnuclei interpolaris (SpVi) and subnuclei caudalis (SpVc) and the dorsal column nucleus-based lemniscal and cortical pathway. Thus, the deficits in the trigeminal system of Drg11-/- mice are specific to the PrV. Our results demonstrate that Drg11 is essential for proper cellular differentiation and, subsequently, for the formation of the whisker-related lemniscal and cortical structures.

Afferent Pathways↗

PubMed2003

Structural plasticity and the evolution of antibody affinity and specificity.

The germline precursor to the ferrochelatase antibody 7G12 was found to bind the polyether jeffamine in addition to its cognate hapten N-methylmesoporphyrin. A comparison of the X-ray crystal structures of the ligand-free germline Fab and its complex with either hapten or jeffamine reveals that the germline antibody undergoes significant conformational changes upon the binding of these two structurally distinct ligands, which lead to increased antibody-ligand complementarity. The five somatic mutations introduced during affinity maturation lead to enhanced binding affinity for hapten and a loss in affinity for jeffamine. Moreover, a comparison of the crystal structures of the germline and affinity-matured antibodies reveals that somatic mutations not only fix the optimal binding site conformation for the hapten, but also introduce interactions that interfere with the binding of non-hapten molecules. The structural plasticity of this germline antibody and the structural effects of the somatic mutations that result in enhanced affinity and specificity for hapten likely represent general mechanisms used by the immune response, and perhaps primitive proteins, to evolve high affinity, selective receptors for so many distinct chemical structures.

Antibody Affinity↗

PubMed2003

Structural evidence for substrate strain in antibody catalysis.

The crystal structure of the Michaelis complex between the Fab fragment of ferrochelatase antibody 7G12 and its substrate mesoporphyrin has been solved to 2.6-A resolution. The antibody-bound mesoporphyrin clearly adopts a nonplanar conformation and reveals that the antibody catalyzes the porphyrin metallation reaction by straining/distorting the bound substrate toward the transition-state configuration. The crystal structures of the Fab fragment of the germ-line precursor antibody to 7G12 and its complex with the hapten N-methylmesoporphyrin have also been solved. A comparison of these structures with the corresponding structures of the affinity-matured antibody 7G12 reveals the molecular mechanism by which the immune system evolves binding energy to catalyze this reaction.

Antibodies↗

PubMed2003

Steroidal glycosides from the rhizomes of Dioscorea spongiosa.

A water extract of the rhizomes of Dioscorea spongiosa, which showed antiosteoporotic activity, was examined, and four new pregnane glycosides, named spongipregnolosides A-D (1-4), and two new cholestane glycosides, named spongiosides A (5) and B (6), were isolated together with 15 known glycosides. Their structures were determined on the basis of spectroscopic analysis and chemical methods. Among the isolated compounds, spongioside A (5), hypoglaucin G (7), methylprotodioscin (8), and (R)-oct-1-en-3-yl O-alpha-l-arabinopyranosyl-(1-->6)-alpha-d-glucopyranoside (9) showed potent inhibition against bone resorption induced by parathyroid hormone in a bone organ culture system.

Animals↗

PubMed2003

Lmx1b is essential for the development of serotonergic neurons.

The specification and differentiation of serotonergic (5-HT) neurons require both extrinsic signaling molecules and intrinsic transcription factors to work in concert or in cascade. Here we identify the genetic cascades that control the specification and differentiation of 5-HT neurons in mice. A major determinant in the cascades is an LIM homeodomain-containing gene, Lmx1b, which is required for the development of all 5-HT neurons in the central nervous system. Our results suggest that, during development of 5-HT neurons, Lmx1b is a critical intermediate factor that couples Nkx2-2-mediated early specification with Pet1-mediated terminal differentiation. Moreover, our data indicate that genetic cascades controlling the caudal and rostral 5-HT neurons are distinct, despite their shared components.

Animals↗

PubMed2003

[Analysis of an inherited FVII deficiency pedigree caused by homozygosity of Thr359Met].

OBJECTIVE: To explore the gene mutation type of an inherited coagulation factor VII deficiency pedigree. METHODS: FVII:Ag, FVII:C, FVIIa were detected to classify deficiency type. FVII gene mutations were analysed in the proband and her family members by DNA directly sequencing. Biostructural pathology of the identified mutation was analysed by molecular modeling. RESULTS: Homozygosity of C-->T transition at position 11514 in exon 8 resulting in Thr359Met was identified in the proband, and heterozygosity for Thr359Met was confirmed in her parents, her son and some other family members. Thr359Met induces CRM-deficiency. It is found by computer simulated molecular model that the replacement of Thr by Met which has a larger and longer side chain might cause steric hindrance, and change the number of H-bonds. CONCLUSIONS: Homozygous missense mutation Thr359Met was found in a pedigree of hereditary FVII deficiency. This mutation might change the configuration of protein molecule and result in severe FVII deficiency.

Adolescent↗

PubMed2003

[Knockout of tyrR gene in Escherichia coli and its effects on the phenylalanine biosynthesis].

TyrR is a global regulation protein encoded by tyrR gene which controls several transcriptional units involving biosynthesis and transportation of aromatic amino acids in Escherichia coli. In this work, the tyrR gene was knocked out by a double-cross homologous recombination. The tyrR- mutant was verified by structural identification by PCR and sequencing, and functional demonstration using lacZ reporter gene. In tyrR- mutant, the activities of two key enzymes in the phenylalanine biosynthesis pathway, whose expression was controlled by TyrR, DAHPS and AT, had been shown to elevate by a 1.08-fold and 2.70-fold compared with the parent strain, respectively. The yield of phenylalanine biosynthesis in the mutant was 1.59 times higher than that of wild type strain. The repression on the transcription of aroP, encoding an aromatic amino acid permease, was eliminated, resulting in a 70.2% increase of the aromatic amino acid transportation in tyrR- mutant strain.

Amino Acid Transport Systems↗