Biomedical subjects

H Chu

Publications and source records attributed to H Chu.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Does response of rape to La and critical concentration of La in red earth].

The effects of different concentration of La added in red soil on the growth, yield, content of chlorophyll and peroxidase(POD) activity of rape were studied by pot experiments. The results showed that the growth and yield of rape could be improved by low concentration of La3+, however there was no significant difference between the treatment and the control, and inhibited when the dose were more than 300 mg kg-1 and killed after 600 mg.kg-1 La was added. The decrease of chlorophyll content and chlorophyll a/b was observed when the exogenous concentration of La was more than 15 mg.kg-1. POD activity increased gradually with increasing concentration and prolonging reaction. The feasible application level of La was suggested to be below 15 mg.kg-1.

Chlorophyll↗

PubMed2001

[Human factor VIII expression in retrovirus vector-transduced bone marrow stromal cells].

OBJECTIVE: To explore the feasibility of bone marrow stromal cells (BMSCs) used for gene therapy of hemophilia A. METHODS: Murine and rabbit BMSCs were transduced with a recombinant replication-incompetent retrovirus LNC-FVIII delta B, which encloses a B-domain-deleted (760aa-1,639aa) human factor VIII cDNA. An optimized protocol involving temperature declining (32 degrees C) and centrifugation was used. Antigen and coagulant activity of human FVIII in the cell culture medium were measured by ELISA assay and one-stage method, respectively. Semi-quantitative PCR was performed for the transduction efficiencies. Western blot was used for FVIII protein analysis. RESULTS: Transduction efficiencies were increased 5- to 8-fold by temperature decline and centrifugation, which resulted in high expression and secretion of FVIII in transduced mouse[(556 +/- 80) ng/10(6) cells/24 hr] and rabbit [480 +/- 56) ng/10(6) cells/24 hr] BMSCs. Coagulant activities of human FVIII secreted from transduced murine and rabbit BMSCs were 2.42 U/10(6) cells/24 hr and 1.8 U/10(6) cells/24 hr, respectively. Western blot analysis demonstrated that the B domain-deleted FVIII cDNA was secreted predominantly as heavy and light chain heterodimers that resemble the native forms in human plasma. CONCLUSIONS: It was demonstrated that the BMSCs system has potential utility in the gene therapy for hemophilia A.

Animals↗

PubMed2001

High level expression of human factor VIII in mammalian cells after retroviral-mediated gene transfer.

OBJECTIVE: To develop a retroviral-mediated high efficient expression system of human coagulation factor VIII. METHODS: The LNC-FVIIIBD retroviral vector was generated by cloning a human B-domain-deleted (760aa-1639aa) Factor VIII (FVIII) cDNA (FVIII cDNA BD) into the retroviral vector pLNCX. Several mammalian cell lines, including NIH3T3, CHO, Cos-7 and human hepatic cell line, L-02, were transduced with viral supernatant from the highest virus-producing PA317 clone. Antigen and coagulant activity of human FVIII in cell culture medium were measured by ELISA and a one-stage method, respectively. RT-PCR was performed for the detection of FVIIIBD mRNA. RESULTS: Human FVIII was expressed in all four target cells, with the highest FVIII expression observed in NIH3T3. The coagulant activity of secreted FVIII was up to 1.6 U/10(6) cells.24 hrs-1, and the FVIII antigen was 500 ng/10(6) cells.24 hrs-1. FVIII coagulant activity and antigen expressed by transduced CHO cells were 0.12 U/10(6) cells.24 hrs-1 and 62.4 ng/10(6) cells.24 hrs-1, respectively. Human FVIII expression was relatively low in Cos-7 and L-02 cells. RT-PCR results demonstrated transcription of FVIII cDNA BD in the target cells. CONCLUSIONS: The constructed retroviral vector was able to direct high level expression of human FVIII in various mammalian cell lines. It has potential utility in the future gene therapy for Hemophilia A.

Animals↗

PubMed2001

[Carrier detection and prenatal diagnosis for hemophilia A].

OBJECTIVE: To establish a simple, rapid carrier detection and prenatal diagnosis system for hemophilia A. METHODS: Intron 22 inversion in FVIII gene was directly examined by long distance polymerase chain reaction. Polymorphism of factor VIII intragenic RFLP of Bcl I, STR within intron 13 and 22, and extragenic DXS 52 (St 14) VNTR loci by hereditary linkage analysis were assayed. RESULTS: The diagnostic rates of these loci were 47.6% (intron 22 inversion), 27.8% (Bcl I), 28.6% and 29.4% (STR within intron 13 and 22), and 81.3% (DXS52), respectively. The overall diagnostic rate in 21 families was 94.7%. CONCLUSIONS: The diagnosis in hemophilia A patients or carriers can be made if intron 22 inversion is present. The intragenic and extragenic loci hereditary linkage analysis could be used to establish the diagnosis in intron 22 inversion negative patients.

Factor VIII↗

PubMed2001

[Analysis of the reason that patients with chronic sinusitis having a negative CT manifestation].

OBJECTIVE: To explore the reason why the CT manifestation of the patients with chronic nasosinusitis is negative. METHOD: To analyze the clinical and CT manifestation of the patients with chronic sinusitis having a negative CT manifestation. RESULT: Pathological changes were found in all 8 patients during the course of endoscopic sinus surgery, such as pus storing in the sinus cavity, mucous swelling polypoidly, small polyps formation and so on. CONCLUSION: The reasons that the patients with chronic sinusitis having a negative CT manifestation are, 1. CT scan can only give a static one-off image, 2. partial volume effect, 3. maybe result from the location of CT scan and the resolving power of tomograph, 4. maybe attribute to the pathological classify of chronic sinusitis.

Adolescent↗

PubMed2000

Removal of SO2 and NO from flue gas by wet scrubbing using an aqueous NaClO2 solution.

This study used a NaClO2/NaOH solution as the additive/absorbent to determine the extent of NOx removal in a wet scrubbing system. A combined SOx/NOx removal system was also tested. The experiments were performed in a bench-scale spraying sieve tray wet scrubber in a continuous mode. The operating variables included NO and SO2 concentrations, L/G ratio, molar ratio, and initial pH. The results of the individual DeNOx experiments show that the maximum DeNOx efficiencies ranged from 3.1 to 12.6%. The results of the combined DeSOx/DeNOx experiments show that the maximum DeNOx and DeSOx efficiencies ranged from 36.6 to 71.9% and from 89.4 to 100.0%, respectively. The major parameters affecting NOx removal efficiencies are the L/G ratio and the dosage of additive. The major parameter influencing DeSOx efficiencies is the L/G ratio.

Absorption↗

PubMed2000

The lipid treatment assessment project (L-TAP): a multicenter survey to evaluate the percentages of dyslipidemic patients receiving lipid-lowering therapy and achieving low-density lipoprotein cholesterol goals.

OBJECTIVE: To determine the percentage of patients in the multicenter Lipid Treatment Assessment Project receiving lipid-lowering therapy who are achieving low-density lipoprotein cholesterol (LDL-C) goals as defined by National Cholesterol Education Program (NCEP) guidelines. METHODS: Adult patients with dyslipidemia, who had been receiving the same lipid-lowering therapy for at least 3 months, were assessed at investigation sites. Lipid levels were determined once in each patient at the time of enrollment. The primary end point was the success rate, defined as the proportion of patients who achieved their LDL-C target level as specified by NCEP guidelines. RESULTS: A total of 4888 patients from 5 regions of the United States were studied. Of these, 23% had fewer than 2 risk factors for coronary heart disease (CHD) and no evidence of CHD (low-risk group), 47% had 2 or more risk factors and no evidence of CHD (high-risk group), and 30% had established CHD. Overall, only 38% of patients achieved NCEP-specified LDL-C target levels; success rates were 68% among low-risk patients, 37% among high-risk patents, and 18% among patients with CHD. Drug therapy was significantly (P< or =.001) more effective than nondrug therapy in all patient risk groups. However, many patients treated with lipid-lowering drugs did not achieve LDL-C target levels. CONCLUSIONS: Large proportions of dyslipidemic patients receiving lipid-lowering therapy are not achieving NCEP LDL-C target levels. These findings indicate that more aggressive treatment of dyslipidemia is needed to attain goals established by NCEP guidelines.

Adult↗

PubMed2000

Antibody binding regions on human nerve growth factor identified by homolog- and alanine-scanning mutagenesis.

The binding specificities of a panel of mouse monoclonal antibodies (MAbs) to human nerve growth factor (hNGF) were determined by epitope mapping using chimeric and point mutants of NGF. Subsequently, the MAbs were used to probe NGF structure-function relationships. Six MAbs, which recognize distinct or partially overlapping regions of hNGF, were evaluated for their ability to block the binding of hNGF to the TrkA and p75 NGF receptors in various in vitro assays, which included blocking of TrkA autophosphorylation and blocking of NGF-dependent survival of dorsal root ganglion sensory neurons. Three MAbs (911,912,938) were potent blockers of all activities. Potent blocking of p75 binding occurs only with MAb 909, which recognizes an NGF region identified by mutagenesis as important for NGF-p75 binding. These results are consistent with recently proposed models of binding regions involved in NGF-TrkA and NGF-p75 interactions generated through mutagenic analysis and structure determination of the NGF-TrkA complex. These studies provide insight to the epitope specificities and potency of MAbs that would be useful for physiological NGF blocking studies.

Alanine↗

PubMed2000

[A study on the relationship between serum free alpha-subunit of human chorionic gonadotropin and pregnancy induced hypertension].

OBJECTIVE: To determine the correlation of free alpha subunit of human chorionic gonadotropin (F alpha-hCG) with pregnancy induced hypertension(PIH), and to observe the immunohistochemical expression of alpha-hCG in placentae from PIH. METHODS: Serum was obtained from 66 successive pregnant women diagnosed with PIH (5 mild, 8 middle and 53 severe) at 21-43 weeks' gestation. A group of 30 non PIH gravid women were used as controls. The serum was assayed for F alpha-hCG by monoclonal technology and human prolactin was assayed for correcting the blood contraction. Immunolocalization and the intensity of the immunohistochemical stained in the placentae from 13 PIH and 13 normal pregnancies. RESULTS: Significant difference was noted between the two groups mean of F alpha-hCG (the control group VS PIH group was 528 +/- 421 IU/L VS 222 +/- 129 IU/L, P < 0.001); no significant between two groups of hPL. The mean value of F alpha-hCG of severe PIH revealed significantly higher than the mild and moderate (569 +/- 455 IU/L VS 363 +/- 159 IU/L, P < 0.01); The leve of F alpha-hCG in group of proteinuria > or = +++ was higher than that of proteinuria < +++ (598 +/- 474 IU/L VS 425 +/- 291 IU/L, P > 0.05). The intensity of alpha-hCG immunostaining in syncytiotrophoblast was significantly increased in 13 PIH compared with the control group (the strong positive rate 10/13 VS 3/13 P < 0.025). CONCLUSIONS: The level of F alpha-hCG are significantly higher in PIH compared with controls. The more severe the higher level of F alpha-hCG is in PIH. The higher level of alpha-hCG has the basement of placentae pathology.

Female↗

PubMed2000

[Effects of holothuria glycosaminoglycan on the expression of tissue factor and thrombomodulin in stimulated endothelial cells].

OBJECTIVE: To study the mechanism of antithrombotic effects of holothuria glycosaminoglycan (GAG). METHODS: Endothelial cells from human umbilical vein which were pre-induced with 1 mg/L lipopolysaccharide, were treated by GAG (1 mg/L, 5 mg/L, and 10 mg/L, respectively) and 5 mg/L heparin as a control for 6 hours. Procoagulant activity (PCA), the expressions of tissue factor (TF) antigen and thrombomodulin (TM) antigen and their mRNA transcriptions were investigated. RESULTS: GAG could down-regulate the expression of TF antigen and mRNA, up-regulate the expression of TM antigen and mRNA, down-regulate the PCA of stimulated endothelial cells. CONCLUSION: Down-regulating TF expression and up-regulating TM expression of stimulated endothelial cells may be one of the mechanisms of GAG antithrombosis.

Animals↗

PubMed2000

[Mechanism of tissue factor expression on NB4 cells down-regulated by all-trans retinoic acid and arsenic trioxide].

OBJECTIVE: To investigate molecular mechanism of tissue factor (TF) expression on acute promyelocytic leukemia cell line NB4 cells down-regulated by all-trans retinoic acid (ATRA) and arsenic trioxide (As(2)O(3)). METHODS: Cyclohexamide (CHX) inhibition test for de novo protein synthesis and actinomycin D (Act D) inhibition test for RNA synthesis were used to check the effect of ATRA on the TF expression. TF antigen of U937 cells transfected with pMSCV-PML-RARalpha treated with or without ATRA and As(2)O(3) was detected. RESULTS: CHX treatment completely suppressed the down-regulation effect of ATRA on the TF mRNA expression, Act D inhibition test showed that half-life of TF mRNA in treated NB4 cells was shortened to about 30 min from that of around 60 min in untreated NB4 cells. The TF antigen contents in U937 cells transfected with pMSCV-PML-RARalpha were significantly higher than that in transfected U937 cells with retrovirus vector. Both ATRA and As(2)O(3) could down-regulate the TF antigen level in U937 cells transfected with or without PML-RARalpha. CONCLUSION: The modulation of the TF mRNA expression in NB4 cells by ATRA might be indirect. TF mRNA destabilization was involved in the TF regulation process mediated by ATRA. Elevated TF antigen level in U937 cells transfected with pMSCV-PML-RARalpha may be related to the fusion protein PML-RARalpha. The down-regulation effect of ATRA and As(2)O(3) on the TF expression of U937 cells might not involve the fusion protein.

Antineoplastic Agents↗

PubMed2000

[Retroviral-mediated high efficient in vitro expression of human coagulation factor VIII].

OBJECTIVE: To develop a retroviral-mediated high efficient expression system of human coagulation factor VIII. METHODS: The retroviral vector LNC-VIIIBD was generated by cloning a B-domain-deleted FVIII cDNA (760aa - 1639aa) into retroviral vector pLNCX. Several cell lines including NIH3T3, CHO, COS-7 and human hepatic cell line L-02 were infected with viral supernatant from the highest productive PA317 clones. The antigen and procoagulant activity of human FVIII in the cell culture medium were measured by ELISA assay and one-stage method, respectively. RT-PCR was performed for the detection of F VIII BD mRNA. RESULTS: Human FVIII was expressed in all four target cells. The highest expression was observed in NIH3T3, the procoagulant activity of secreted FVIII was up to 1.6 U, and the FVIII antigen was 500 ng by 10(6) cells/ml in 24 hours, respectively. CONCLUSION: The constructed retroviral vector was able to generate high level expression of human FVIII in some cell lines, and it might have potential utility in the gene therapy for Hemophilia A.

3T3 Cells↗

PubMed1999

Neuronal overexpression of APPL, the Drosophila homologue of the amyloid precursor protein (APP), disrupts axonal transport.

The two pathological hallmarks of Alzheimer's disease, amyloid plaques and neurofibrillary tangles, involve two apparently unrelated proteins, the amyloid precursor protein (APP) and Tau. Although it is known that aberrant processing of APP is associated with Alzheimer's disease, the definitive role of APP in neurons is not yet clear. Tau regulates microtubule stabilization and assembly in axons and is, thus, an essential component of the microtubule-associated organelle transport machinery. Although several groups have reported physical interaction between APP and Tau, and induction of Tau phosphorylation by APP and beta-amyloid peptide, the functional connection between APP and Tau is unclear. To explore the possibility that the functions of these two proteins may somehow converge on the same cellular process, we overexpressed APPL, the Drosophila homologue of APP, along with Tau in Drosophila neurons. Panneural coexpression of APPL and Tau resulted in adults that, upon eclosion, failed to expand wings and harden the cuticle, which is suggestive of neuroendocrine dysfunction. We analyzed axonal transport when Tau and APPL were coexpressed and found that transport of axonal cargo was disrupted, as evidenced by increased retention of synaptic proteins in axons and scarcity of neuropeptide-containing vesicles in the distal processes of peptidergic neurons. In an independent approach, we demonstrated genetic interaction and phenotypic similarity between APPL overexpression and mutations in the Kinesin heavy chain (Khc) gene, the product of which is a motor for anterograde vesicle trafficking.

Amyloid beta-Protein Precursor↗

PubMed1999

Association between HPV 16/18 infection and expression of P53 protein in laryngeal papillomas.

To understand the relationship between expression of P53 protein and HPV16/18 infection in laryngeal papillomas, PCR and immunohistochemical techniques were used to examine the paraffin-embedded tissue samples of laryngeal papillomas from 35 subjects. HPV 16/18-DNA was found in 24 cases of laryngeal papillomas (68.8%). Overexpression of P53 protein was detected in 19 cases (54.3%). Both HPV16/18-DNA and overexpression of P53 protein were demonstrated in 12 cases of laryngeal papillomas (34.3%). Our results suggest that HPV16/18 infection and P53 gene mutation are associated with pathogenesis of laryngeal papillomas. The relation between HPV infection and P53 mutation in tissues of laryngeal papillomas remains to be clarified.

Human papillomavirus 16↗

PubMed1999

Leginon: a system for fully automated acquisition of 1000 electron micrographs a day.

We have developed a system to automatically acquire large numbers of acceptable quality images from specimens of negatively stained catalase, a biological protein which forms crystals. In this paper we will describe the details of the system architecture and analyze the performance of the system as compared to a human operator. The ultimate goal of the system if to automate the process of acquiring cryo-electron micrographs.

Automation↗

PubMed1999

Validation of a rat pheochromocytoma (PC12)-based cell survival assay for determining biological potency of recombinant human nerve growth factor.

A method has been validated, according to the Guidelines of the International Conference on Harmonization (ICH), for precise quantitation of the biological activity of recombinant human nerve growth factor (rhNGF) for lot release testing. The assay is based on the survival of a subclone of rat pheochromocytoma PC12 cells (PC12-CF) in response to rhNGF. Cell survival is measured by monitoring the reduction, by living cells, of the alamarBlue dye into a red form which is highly fluorescent. The assay is simple, has high throughput (performed in 96-well microtiter plates) and shows reproducible dose-response curves in the concentration range of 0.2-50 ng/ml. The method was validated for its linearity, accuracy, precision, robustness, and to meet current regulatory requirements. The assay demonstrated good linearity, yielding a coefficient of determination of 0.9902. Sample recovery studies demonstrated an accuracy ranging from 96 to 98%. The repeatability of the assay and intermediate precision had coefficients of variation (CV) of <9%. The assay was stability-indicating since it was able to detect changes in rhNGF samples degraded by protease treatment and in a number of isolated rhNGF variants. Robustness was demonstrated by the relative insensitivity of the assay to small deliberate changes in key method parameters. The validation data, provided in this manuscript, indicate that the newly described bioassay for rhNGF is robust, accurate, precise, and suitable for lot release potency testing of rhNGF.

Animals↗

PubMed1999

Agonist-directed signaling of serotonin 5-HT2C receptors: differences between serotonin and lysergic acid diethylamide (LSD).

For more than 40 years the hallucinogen lysergic acid diethylamide (LSD) has been known to modify serotonin neurotransmission. With the advent of molecular and cellular techniques, we are beginning to understand the complexity of LSD's actions at the serotonin 5-HT2 family of receptors. Here, we discuss evidence that signaling of LSD at 5-HT2C receptors differs from the endogenous agonist serotonin. In addition, RNA editing of the 5-HT2C receptor dramatically alters the ability of LSD to stimulate phosphatidylinositol signaling. These findings provide a unique opportunity to understand the mechanism(s) of partial agonism.

3T3 Cells↗

PubMed1998

Formation and specification of ventral neuroblasts is controlled by vnd in Drosophila neurogenesis.

During Drosophila neural development, neuroblasts delaminate from the neuroectoderm of each hemisegment in a stereotypic orthogonal array of five rows and three columns (ventral, intermediate, and dorsal). Prevailing evidence indicates that the individual neuroblast fate is determined by the domain-specific expression of genes along the dorsoventral and anteroposterior axis. Here, we analyze the role of Vnd, a NK-2 homeodomain protein, expressed initially in the ventral neuroectoderm adjacent to the ventral midline, in the dorsoventral patterning of the neuroectoderm and the neuroblasts. We show that in vnd null mutants most ventral neuroblasts do not form and the few that form do not develop ventral fates, but instead develop intermediate-like fates. Furthermore, we demonstrate that Vnd influences the gene expression patterns in the ventral proneural clusters and neuroectoderm, and that its action in neuroblast formation includes, but is not exclusive to the activation of proneural AS-C genes. Through the use of GAL4/UAS gene-expression system we show that ectopic Vnd expression can promote ventral-like fates in intermediate and dorsal neuroblasts and can suppress certain normal characteristics of the intermediate and dorsal neuroectoderm. Our results are discussed in the context of the current evidence in dorsoventral patterning in the Drosophila neuroectoderm.

Animals↗