Biomedical subjects

Kai Yang

Publications and source records attributed to Kai Yang.

50 records · Page 3Linked to original sources

PubMed2003

Genome-wide linkage analysis using cross-sectional and longitudinal traits for body mass index in a subsample of the Framingham Heart Study.

To evaluate linkage evidence for body mass index (BMI) using both cross-sectional and longitudinal data, we performed genome-wide multipoint linkage analyses on subjects who had complete data at four selected time points (initial, 8th, 12th, and 16th year following the initial visit) from the Framingham Heart Study. The cross-sectional measures included BMI at each of the four selected time points and the longitudinal measure was the within-subject mean of BMI at the above four time points. Using the variance components method, we consistently observed the maximum LOD score out of the genome scan using BMI at each time point and the mean of BMI between 049xd2 and GATA71H05 on chromosome 16. The highest LOD score (3.0) was at time point 1, while the lowest (1.9) was at time point 4. We also observed other suggestive linkages on chromosome 6, 10, and 18 at time point 1 only. The longitudinal measure we studied (mean of BMI) did not provide greater power to identify a positive linkage than some of the cross-sectional measures (e.g., time point 1). The changing of linkage evidence over time provided some insights on the variation of genetic effect on BMI with aging. There may be a QTL on chromosome 16 that contributes to BMI and this locus, and maybe others, is more likely to affect BMI during early adulthood.

Adult↗

PubMed2003

Validation of T10-T11 finite element model and determination of instantaneous axes of rotations in three anatomical planes.

STUDY DESIGN: A finite element (FE) model of thoracic spine (T10-T11) was constructed and used to determine instantaneous axes of rotation (IARs). OBJECTIVES: To characterize the locations and loci of IARs in three anatomic planes. SUMMARY OF BACKGROUND DATA: The center of rotation is a part of a precise method of documenting the kinematics of a spinal segment for spinal stability and deformity assessments and for implant devices study. There is little information about loci of IARs in thoracic spine. METHODS: A FE model of thoracic spine (T10-T11) was developed and validated against published data. The validated model was then used to determine the locations and loci of IARs in three anatomic planes. RESULTS: Within the validated range, The IARs locations and loci were found to vary with the applied pure moments. Under flexion and extension pure moments, the loci of IARs were tracked anterosuperiorly for flexion and posteroinferiorly for extension with rotation between the superior endplate and the geometrical center of the inferior vertebra T11. Under left and right lateral bending pure moments, the loci were detected to diverge latero-inferiorly from the mid-height of the intervertebral disc, then converge medio-inferiorly toward the geometrical center of the inferior vertebra T11. For axial rotation, the IARs were located between anterior nucleus and anulus and found to diverge in opposite direction latero-posteriorly with increasing left and right axial torque. CONCLUSIONS: The results of IARs would provide further understanding to the kinematics and biomechanical responses of the human thoracic spine, which is important for the diagnosis of disc degeneration and implant study.

Biomechanical Phenomena↗

PubMed2003

Characterization of a chitin-binding protein GP37 of Spodoptera litura multicapsid nucleopolyhedrovirus.

The GP37 amino acid sequence of Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) was compared with other baculovirus GP37, entomopoxvirus fusolin, the enhancing factor of Pseudaletia separata entomopoxvirus, and Alteromonas sp. chitin-binding protein 1. In these proteins, five 'conserved regions' previously reported constitute a chitin-binding domain. SpltMNPV GP37 effectively bound to purified crab shell chitin and the dissociation constant (Kd) for binding was 0.28 microM. Immunofluorescence analysis indicated that SpltMNPV GP37 was located in both cytoplasm and nucleus. Immunoblot analysis revealed that this protein was present in the envelopes of both occlusion body-derived virus and budded virus. Further analysis suggested that GP37 may bind to the chitin component of the peritrophic membrane of S. litura larvae.

Amino Acid Sequence↗

PubMed2003

Characterization of bro-b gene of Spodoptera litura multicapsid nucleopolyhedrovirus.

Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) ORF125 (designated as the bro-b gene) is a member of the unique multigene family called the baculovirus repeated ORFs (bro) family. Computer-assisted analysis revealed that BRO-B contains a conserved Bro-N domain in its N-terminus and a single-stranded DNA (ssDNA) binding motif in the middle region. In vitro the bro-b gene transcription was present at 12 h post-infection (p.i.) and remained detectable up to 96 h p.i. Western blot analysis of BRO-B expression with an antiserum made against 6xHis tagged BRO-B expressed in Escherichia coli showed that it was present from 12 h through 96 h p.i. in vitro. Structural localization revealed that BRO-B could be found in the nucleocapsid components of both occlusion-derived virus (ODV) and budded virus (BV). Immunofluorescence analysis indicated that BRO-B is located only in the nucleus of infected S. litura cells. Furthermore, Western blot analysis indicated that BRO-B was associated with nuclear structures. These results suggested that BRO-B might be a nuclear-associated protein.

Amino Acid Motifs↗

PubMed2003

[In vitro study of the effect of nm23-H1 on metastasis ability and chemo-sensitivity of Acc-M cell lines].

OBJECTIVE: To transfect nm23-H1 into the Acc-M cell lines in a safe, high-efficiency and low-toxicity way, and then to find out whether nm23-H1 affects the metastasis ability and chemo-sensitivity of Acc-M cell lines. METHODS: Lipofect was used to transfect nm23-H1 into Acc-M cell lines. The difference in expression of nm23-H1 between the transfected and non-transfected cell lines was detected by immunohistochemistry. Then by use of transwell-room and wash way, the difference in invasion and metastasis ability between the transfected and non-transfected cell lines was tested. MTT method was adopted in finding the change of chemo-sensitivity. RESULTS: Using pCMV-Neo-Bam system, we observed the stable expression of nm23-H1 and the significant difference in Nucleoside Diphosphate kinase-A, expression between the transfected and non-transfected Acc-M cell lines. The metastasis ability of transfected Acc-M cell lines decreased significantly. The chemo-sensitivity of transfected Acc-M cell line to cis-diamminedichloroplatin (C-DDP) increased significantly. CONCLUSION: nm23-H1 can inhibit the metastases of Acc-M cell lines significantly and can increase the chemo-sensitivity to C-DDP significantly.

Animals↗

PubMed2003

[Clinical application of anticancer nanoparticles targeting metastasis foci of cervical lymph nodes in patients with oral carcinoma].

OBJECTIVE: The aim of this study was to investigate the target delivery of Cucurbitacin BE (CuBE) to cervical lymph nodes by peri-oral-cancer submucosal injection of the average diameter 85 nm Cucurbitacin BE poly-lactic acid nanoparticles (CuBE-PLA-NP) and evaluate its clinical therapy efficacy. METHODS: CuBE and CuBE-PLA-NP were respectively injected into peri-oral-cancer submucosa at 2, 12, 24, 48, 72, 96, 120, 144, 168 and 192 hours before operation in 26 patients with oral cancer. The concentrations of CuBE in cervical lymph nodes and blood were measured by high performance liquid chromatography (HPLC) at every time point. Cancer cell degeneration and necrosis in metastasis foci of cervical lymph nodes were observed using light microscope and electron microscope. RESULTS: (1) The CuBE concentrations in cervical lymph nodes after CuBE-PLA-NP injection were far higher than those after CuBE injection at every time point, the duration of CuBE existing in the cervical lymph nodes in CuBE-PLA-NP group was far longer than those in CuBE group, the area under the CuBE concentrations-time curve of the cervical lymph nodes in CuBE-PLA-NP group was 43.67 times as many as that in CuBE group; (2) The CuBE ratio of maximum concentrations in the cervical lymph nodes in CuBE-PLA-NP group was 106.46 times as high as that in CuBE group; (3) The CuBE concentrations in the blood in CuBE-PLA-NP group was far lower than that in CuBE group; (4) Cancer cell necrosis and degeneration in the metastasis foci of cervical lymph nodes were found in CuBE-PLA-NP group, necrosis and degeneration were not found in CuBE group. CONCLUSION: The peri-oral-cancer submucosa injection of the average diameter of 85 nm CuBE-PLA-NP can specifically delivery CuBE to the cervical lymph nodes, enhance treatment efficiency, and reduce general toxicity.

Adult↗

PubMed2003

[The study of cucurbitacin BE polylactic acid nanoparticles delivering cucurbitacin BE to metastasized cervical lymph nodes in mice with oral cancer].

OBJECTIVE: The aim of this study was to investigate the delivery of Cucurbitacin BE to cervical lymph nodes by peri-cancer submucosal injection of the average diameter 85 nm Cucurbitacin BE polylactic acid nanoparticles (CuBE-PLA-NP). METHODS: Cervical lymph node metastasis model of mice oral cancer was established and CuBE-PLA-NP and CuBE were injected in peri-cancer submucosal of the mice respectively, the concentration in blood, heart, liver, spleen, lung, kidney and cervical lymph node were measured by high performance liquid chromatography at fifteen time points, Targeted cervical lymph nodes were evaluated by targeting index, selectivity index, targeting efficiency, relative targeting efficiency and ratio of maximum concentration. RESULTS: (1) The CuBE concentration in the cervical lymph nodes after CuBE-PLA-NP injection was far higher than that after CuBE injection at every time point, the CuBE duration in the cervical lymph nodes in CuBE-PLA-NP group was far longer than that in CuBE group; (2) The five targeted values of the cervical lymph nodes in CuBE-PLA-NP group was far higher than that in CuBE group; (3) The CuBE concentration in blood, heart, liver, spleen, lung and kidney in CuBE-PLA-NP group was far lower than that in CuBE group. CONCLUSION: The CuBE-PLA-NP can specifically deliver CuBE to the cervical lymph nodes by peri-cancer submucosal injection, increase CuBE concentration and duration in metastasized cervical lymph nodes, and decrease drug concentration of other organs.

Animals↗

PubMed2003

[Study on chemical constituents from Mycale parishi].

Three alkaloids have been isolated from Mycale parishi collected from Naozhou Island of Zhanjiang in China, their structure were identified as 1-(4-Hydroxy-5-hydroxymethyl-tetrahydro-furan-2-yl)-5-methyl-1H-pyrimidine- 2,4-dione(I), 1H-Pyrimidine-2,4-dione(II), Pentacosanoic acid (2-hydroxy-1-hydroxymethyl-heptadec-3-enyl)-amide(III), respectively on the basic of the spectral data of MS, 1H NMR, 13CNMR.

Alkaloids↗

PubMed2003

[Establishment of Spodoptera exigua multicapsid nucleopolyhedrovirus BAC-TO-BAC expression system].

Present studies describe the successful establishment of Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV) BAC-TO-BAC expression system. The mini-F-lacZ-attTn7-kan fragment (Luckow et al, 1993) was inserted into SeMNPV US1 isolate (SeUS1) at polyhedrin gene locus by directly cloning. The recombinant virus containing low-copy-number mini-F replication, which named bacmid, can propagate in Escherichia coli. Because SeUS1 isolate is make up of several genotypes and one bacmid carries one SeMNPV genotype, the SeUS1 BAC library is established by all SeMNPV bacmids (SeBAC). REN analysis for 111 SeBAC shows that SeUS1 consists of the genotype with whole SeMNPV genetic information and several genotypes with various different deletions. Progeny virus can be produced in insect cell line after transfection with SeBAC10, which carries the whole SeMNPV genome. So SeBAC10 is a shuttle vector that can replicate in eukaryocyte as well as prokaryocyte. Considering the insert mutation of SeMNPV polyhedrin gene (Seph) in SeBAC10, Seph was reintroduced into the bacmid by site-specific transposon-mediated insertion at attTn7, the target site for the bacterial transposon Tn7. The derived recombinant SeBAC10 was named SeBAC10ph. After SeBAC10ph was transfected into Se301 cells (a susceptible insect cell line to SeMNPV), cytopathogenic effect was shown and polyhedra appeared, which indicate that the foreign gene (Seph) is expressed.

Animals↗

PubMed2002

Infection of wild-type Autographa californica multicapsid nucleopolyhedrovirus induces in vivo apoptosis of Spodoptera litura larvae.

Direct evidence of in vivo apoptosis of Spodoptera litura larvae was demonstrated by haemocoel inoculation with wild-type Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) budded virus (BV). In sharp contrast to natural infection, cadavers did not melt, liquefy and melanize. Typical morphological changes of apoptosis in insect haemocytes post-infection, including blebbing of the cell surface, chromatin margination and condensation, vacuolization of the cytoplasm and formation of apoptotic bodies, were observed by light and electron microscopy. Total DNAs extracted from virus-infected haemocytes showed DNA ladders. Cleavage of chromatin DNA by endogenous endonucleases were detected in the cells of most tissues cells, including epithelial cells and fat body cells, using terminal dUTP nick end labelling assays. Virogenic stroma and viral nucleocapsids could be seen in the nuclei of a few haemocytes. Yields of BV and OV (occluded virus) produced from the infected S. litura larvae were much lower than from the infected S. exigua larvae. These data suggest that host apoptotic responses to virus infection reduce AcMNPV spread at the level of the organism and that apoptosis could be a host-range limiting factor for baculovirus infections.

Animals↗

PubMed2002

Pivotal role of the non-hr origin of DNA replication in the genesis of defective interfering baculoviruses.

The generation of deletion mutants, including defective interfering viruses, upon serial passage of Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV) in insect cell culture has been studied. Sequences containing the non-homologous region origin of DNA replication (non-hr ori) became hypermolar in intracellular viral DNA within 10 passages in Se301 insect cells, concurrent with a dramatic drop in budded virus and polyhedron production. These predominant non-hr ori-containing sequences accumulated in larger concatenated forms and were generated de novo as demonstrated by their appearance and accumulation upon infection with a genetically homogeneous bacterial clone of SeMNPV (bacmid). Sequences were identified at the junctions of the non-hr ori units within the concatemers, which may be potentially involved in recombination events. Deletion of the SeMNPV non-hr ori using RecE/RecT-mediated homologous ET recombination in Escherichia coli resulted in a recombinant bacmid with strongly enhanced stability of virus and polyhedron production upon serial passage in insect cells. This suggests that the accumulation of non-hr oris upon passage is due to the replication advantage of these sequences. The non-hr ori deletion mutant SeMNPV bacmid can be exploited as a stable eukaryotic heterologous protein expression vector in insect cells.

Animals↗

PubMed2002

[Generation and analysis of a repeat DNA fragment of SeMNPV by serial undiluted passage in Se301 insect cells].

Two major clades, designated Groups I and II, of nucleopolyhedroviruses (NPVs) from insect hosts have been previously identified. In order to gain insight into DNA replication of Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV, Groups II), the essential cis-acting DNA segments were studied. A strain, named Se-4, was plaque-purified from SeMNPV isolate US1. PCR, ELT-PCR and REN showed that Se-4 was genetically relatively homogeneous and retained the full-length of a hypervariable region which is usually prone to deletion from SeMNPV genome. To study the stability of this isolate in vitro, Se-4 was serially passaged in the Se301 cell line up to 10 times without dilution. Intracellular viral DNA extracted from every passage was analyzed by REN. A novel 3.5 kb PstI fragment was observed in passage 7 and the relative intensities of the bands increased with subsequent passages. In passage 10, the molar ratio of the fragment was much higher than those of any other viral DNA fragments. This fragment was thus expected to contain an important cis-acting element for SeMNPV DNA replication. The fragment was cloned and sequenced and it was found that it overlapped 3 525 bp with the published SeMNPV genome sequence (GenBank AF169823), from 81 014 nt to 84 538 nt. The region contained the SeMNPV non-hr origin (ori) of DNA replication and some ORFs including partial vlf-1, partial p26, Se84 as well asSe83, Se85, Se86, which are unique to SeMNPV. As compared to Autographa californica MNPV (Groups I), which also generated hypermolar DNA fragments containing the non-hr ori by serial undiluted passage in IPLB-SF-21 cell culture, our results provided in vitro evidence that the non-hr ori may also play an important role in the viral infection cycle of Groups II NPVs.

Animals↗

PubMed2002

A study on the difference of craniofacial morphology between oral and nasal breathing children.

OBJECTIVE: The purpose of this study was to compare the difference of craniofacial morphology between oral and nasal breathing children, and discover the relationship between respiratory mode and craniofacial morphology. METHODS: Using the system for the simultaneous measurement of oral and nasal respiration, 34 oral breathing children and 34 nasal breathing children aged from 11 to 14 years were selected. RESULTS: Compared with the nasal-breathing children, the oral-breathing children showed apparently vertical growth pattern. The mandibuler plane Angle of oral breathing children is 39.3, which is significant greater than that of nasal breathing children (P < 0.01). The jans, the oral-breathing children had shorter mandibular body, larger gonion angle, retrusive chin and face (P < 0.05). On the other hand, in the sagittal direction, the oral breathing children may display all kinds of skeletal facial types. There is no significant difference between the two groups. CONCLUSIONS: Oral breathing is one of the factors related to the vertical over-development.

Adolescent↗

PubMed2000

Cloning and Sequence Analysis of the Chitinase Gene of Spodoptera litura Nuclear Polyhedrosis Virus.

Using AcMNPV chiA-containing fragment as a probe, the chitinase gene of Spodoptera litura nuclear polyhedrosis virus (SpltNPV) was localized in two contiguous fragments, XbaI 5.1 kb and 2.1 kb, and the intact SpltNPV chiA gene was obtained by cloning and sequencing those two fragments. The complete open reading frame of the gene was 1 695 nucleotide long, encoding a putative protein of 564 amino acids with molecular weight of 62.9 kD. Sequence analysis further revealed that the 5' noncoding region had a baculovirus late promoter motif TAAG. A polyadenylation signal, AATAAA, was located dowmnstream of the translation stop codon. A putative signal peptide was present at the N-terminus of the protein. This gene shares 57% homology with AcMNPV chitinase gene.

Journal Article↗