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Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 631 records · Page 35Linked to original sources
PubMed2001

Endogenous expression and HLA stabilization assay of Plasmodium falciparum CTL epitope minigene in human HLA-A2. 1 and HLA-B51 cells.

OBJECTIVE: To evaluate the Plasmodium falciparum CTL epitope vaccines in HLA class I allele specific human cell lines that have high frequency among Chinese population. METHODS: Synthesized oligonucleotides encoding for P. f. CTL epitope genes, constructed eukaryotic expression plasmids, transfected the minigenes into HLA class I allele specific human cell lines and identified endogenous expressing of the minigenes by RT-PCR and HLA stabilization assay. RESULTS: Two mini-genes encoding Plasmodium falciparum CTL epitopes were designed and cloned, respectively, into an eukaryotic expressing vector to form TR26 which was restricted to HLA-B51, SH6 which was restricted to HLA-A2. 1, and TS, which had the two aforementioned mini-genes fused in tandem. All of these CTL epitope genes were transfected and endogenously expressed in respective cell lines containing appropriate HLA molecules. The obviously increased expressions of HLA class I molecules were detected in the transfected cell lines. It was demonstrated that the two discrete Plasmodium falciparum epitope genes were effectively processed and presented, and the close proximity of the two epitope genes in one chain as in mini-gene TS did not interfere with the processing and presenting of each epitope gene in corresponding cell line. CONCLUSION: A successful expression and presentation of multiple CTL epitope mini-gene in MHC class I allele specific human cell lines were demonstrated by an in vitro assay, which could be corresponding to the vaccination of CTL vaccines in people with different MHC I molecules. This work also suggested the possibility of constructing a multiple CTL epitope Plasmodium falciparum DNA vaccine that could cover most of Chinese population.

Animals↗
PubMed2001

Flashlamp-pumped pulsed dye laser in treatment of port-wine stains.

OBJECTIVE: To assess the effectiveness of the flashlamp-pumped pulsed dye laser (Photogeneca V, Synosure Corp, Boston, United States) in the treatment of port-wine stains. METHODS: One hundred and ninety-four consecutive patients with port-wine stains were treated with a flashlamp-pumped pulsed dye laser in Peking Union Medical College Hospital from January 1998 to August 1999. RESULTS: Of 194 patients who completed treatment, 56.2% had more than 60% fading of the lesion and only 6.7% had less than 20% fading. An average of 3.6 treatments were needed to achieve more than 60% fading. The response was better in children than in adults, although the difference was not significant. Pigmentary change (usually transient) occurred in 3.1% of patients. CONCLUSIONS: This study confirms the efficacy of the flashlamp-pumped pulsed dye laser in the treatment of port-wine stains in children and adults.

Adolescent↗
PubMed2001

[Identification and cloning of a novel full ORF gene of P. falciparum PDZ domain containing protein].

OBJECTIVE: To identify and clone a novel full ORF gene of P. falciparum PDZ domain containing protein (PfPCP) and study its expression at the erythrocytic stage. METHODS: The primers were designed according to the sequences from P. falciparum genomic database. The full ORF gene of PfPCP was amplified from mRNA of the erythrocytic stage of P. falciparum Hainan strain by RT-PCR. Bio-informatics software were used to analyze PfPCP; PfPCP expression at the erythrocytic stage was studied with Western Blotting. RESULTS: The full ORF gene of PfPCP was 2,076 bp and encoded 691 amino acids. PfPCP contained the typical PDZ domain. Western blotting showed that PfPCP was expressed at the schizont sub-stage of P. falciparum erythrocytic stage. CONCLUSIONS: The novel full ORF gene of PfPCP is cloned. As a PDZ domain containing protein, PfPCP is expressed at the schizont sub-stage of P. falciparum.

Amino Acid Sequence↗
PubMed2001

[Establishment of antigen presenting cells model of Plasmodium falciparum cytotoxic T lymphocyte single epitope vaccine].

OBJECTIVE: To construct plasmodium falciparum cytotoxic T lymphocyte (CTL) single epitope vaccine and establish antigen presenting cells model. METHODS: Gene encoding HLA-A11 restricted plasmodium falciparum CTL epitope (VTCGNGIQVR), which was in high frequency among Chinese population, was chosen and cloned into an eukaryotic expressing vector to form CTL single epitope vaccine: pcDNA3.1/beta 2m/A11. This plasmid was transfected and expressed in cell lines bearing only HLA-A11 molecule. The expressions of HLA class I molecules were accessed by flow cytometry. RESULTS: The CTL single epitope was expressed in HLA-A11 cell lines and an obviously increased expressions of HLA class were detected in the transfected cell lines, and evaluated as mean channel number of fluorescence by flow cytometry (P < 0.05). CONCLUSIONS: CTL single epitope expressing plasmid was constructed and the antigen presenting cells model was established. It was demonstrated that plasmodium falciparum CTL single epitope was effectively processed and expressed. Our work suggested the single-epitope vaccine might provide protection for populations which containing HLA-A11 background.

Animals↗
PubMed2001

[A study on the concentration quenching of Tm3+ upconversion luminescence].

In this work, we have a designation and preparation of MFT glasses for upconversion, the glasses consisted of TeO2 and fluoride: PbF2, AlF3, BaF2, NaF and the impurity Tm2O3. In this glass system the oxide improve forming ability, the fluorides improve the microscopic environment around RE ions in glasses. In this glass host the content of Tm2O3 achieves to 4% mol and crystallization no occurred. A detail study on the concentration quenching of upconversion luminescence for 1G4-->3H6 and 1D2-->3H4 transitions was completed. The experimental results directed that the quenching concentration was 0.6 mol.% and higher 3 times than in other glasses materials. The cross relaxation and mechanism of concentration quenching were discussed.

Attention↗
PubMed2001

[The evaluation of compressive strength of four filling materials for class I cavity].

OBJECTIVE: Compressive strength of four filling materials which are usually used in clinic were evaluated, and the indication of Class I cavity was discussed. METHODS: In vitro, the Class I cavities were prepared on eighty first molars. After filling the cavities with four filling materials, loading was applied with the same speed, and the compressive strength at the fracture point were recorded and analyzed. RESULTS: The compressive strength of silver amalgam was highest, GCFujiIXGP was lower, and 3M composite resin was lowest. CONCLUSION: For Class I cavity of posterior teeth, we should consider the compressive strength of filling materials first, and for anterior teeth, color is most important.

English Abstract↗
PubMed2001

[Administration of leukemic granulocyte colony-stimulating factor to donors: the changes in donor bone marrow cell composition and the transplantation outcome].

OBJECTIVE: To investigate the change of bone marrow cell composition the effect of graft on hemopoietic reconstitution and the incidence of acute graft-versus-host disease (aGVHD) with granulocyte colony-stimulating factor G-CSF administration to donors before marrow harvesting. METHODS: Twenty-four patients with myeloid leukemia underwent allogeneic bone marrow transplantation. The donors of twelve patients (study group) were given G-CSF 250 microg/d for seven days prior to harvesting. The marrow cell composition, the outcome of subsequent engraftment and the occurrence of aGVHD were compared with those in twelve patients without G-CSF (control group). RESULTS: The bone marrow stimulated by G-CSF yielded higher number of nucleated cells, CD34+ cells, CFU-GM and CFU-MK (P < 0.01). The number of T lymphocyte subsets in the graft stimulated with G-CSF was different from that in the control group. The number of CD4+ cells was decreased and that of CD8+ increased. The CD4+/CD8+ ratio was reduced markedly (P < 0.01). The change of CD34+, CD4+, CD8+ percentage and CFU-GM, CFU-MK proliferation in donor bone marrow with and without G-CSF was compared. The same characteristic change as above graft was observed. Hemopoietic reconstitution in the study group after allo-BMT was accelerated. In the study group the days of granulocyte count exceeding 0.5 x 10(9)/L and platelet count exceeding 20 x 10(9)/L were 16 days (range 11 - 23 days) and 17 days (range 14 - 25 days) (in the control group 20.5 day, range 14 - 29 days and 23 days, range 17 - 32 days P < 0.05). Grade II - IV aGVHD did not occur in patients of the study group but in 3 patients of the control group. CONCLUSION: The bone marrow harvested from donor with G-CSF stimulation can accelerate hemopoietic recovery and decrease the incidence of severe aGVHD. The accelerated hematopoietic recovery is associated with increased number of CD34+, CFU-GM and CFU-MK in the graft.

Adolescent↗
PubMed2000

In vitro assembly and structure of trichocyte keratin intermediate filaments: a novel role for stabilization by disulfide bonding.

Intermediate filaments (IF) have been recognized as ubiquitous components of the cytoskeletons of eukaryotic cells for 25 yr. Historically, the first IF proteins to be characterized were those from wool in the 1960s, when they were defined as low sulfur keratins derived from "microfibrils." These proteins are now known as the type Ia/type IIa trichocyte keratins that constitute keratin IF of several hardened epithelial cell types. However, to date, of the entire class of >40 IF proteins, the trichocyte keratins remain the only ones for which efficient in vitro assembly remains unavailable. In this paper, we describe the assembly of expressed mouse type Ia and type IIa trichocyte keratins into IF in high yield. In cross-linking experiments, we document that the alignments of molecules within reduced trichocyte IF are the same as in type Ib/IIb cytokeratins. However, when oxidized in vitro, several intermolecular disulfide bonds form and the molecular alignments rearrange into the pattern shown earlier by x-ray diffraction analyses of intact wool. We suggest the realignments occur because the disulfide bonds confer substantially increased stability to trichocyte keratin IF. Our data suggest a novel role for disulfide bond cross linking in stabilization of these IF and the tissues containing them.

Amino Acid Sequence↗
PubMed2000

Densities, length proportions, and other distributional features of repetitive sequences in the human genome estimated from 430 megabases of genomic sequence.

The densities of repetitive elements in the human genome were calculated in each GC content class using non-overlapping windows of 50kb. The density of Alu is two to three times higher in GC-rich regions than in AT-rich regions, while the opposite is true for LINE1. In contrast, LINE2 and other elements, such as DNA transposons, are more uniformly distributed in the genome. The number of Alus in the human genome was estimated to be 1.4 million, higher than previous estimates. About 40% of the autosomes and approximately 51% of the X and Y chromosomes are occupied by repetitive elements. In total, the human genome is estimated to contain more than 4 million repetitive elements. The GC contents (%) of repetitive elements and their flanking regions were also calculated. The GC contents of almost all kinds of repeats are positively correlated with the window GC contents, suggesting that a repetitive sequence is subject to the same mutation pressure as its surrounding regions, so it tends to have the same GC content as its surrounding regions. This observation supports the regional mutation hypothesis. The only two exceptions are AluYa and AluYb8, the two youngest Alu subfamilies. The GC content of AluYb8 is negatively correlated with that of its surrounding regions, while AluYa shows no correlation, suggesting different insertion patterns for these two young Alu subfamilies. This suggestion was supported by the fact that the average genetic distance between members of AluYb8 in each GC window class is positively correlated with the GC content of the window, but no correlation was found for AluYa. AluYa is more frequent in Y chromosome than in other chromosomes; the same is true for LTR retroviruses. This pattern might be correlated with the evolutionary history of Y chromosome.

Alu Elements↗
PubMed2000

Ginkbilobin, a novel antifungal protein from Ginkgo biloba seeds with sequence similarity to embryo-abundant protein.

A novel single-chained antifungal protein with a molecular weight of 13 kDa displaying an N-terminal sequence with marked similarity to embryo-abundant protein from the white spruce was isolated from the seeds of Ginkgo biloba using ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on SP-Sepharose, and then gel filtration on Superdex 75. The protein, designated ginkbilobin, exerted potent antifungal activity against a variety of fungi, including Botrytis cinerea, Mycosphaerella arachidicola, Fusarium oxysporum, Rhizoctonia solani, and Coprinus comatus. Ginkbilobin exhibited a moderate antibacterial action against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. It suppressed the activity of HIV-1 reverse transcriptase and the proliferation of murine splenocytes.

Animals↗
PubMed2000

Genetic diversity of hantaviruses isolated in china and characterization of novel hantaviruses isolated from Niviventer confucianus and Rattus rattus.

The antigenic and genetic properties of 46 hantaviruses from China, 13 from patients, 23 from rodents, and 10 from unknown hosts, were compared with those of other hantaviruses. The viruses were classified as either Hantaan (HTN) or Seoul (SEO) viruses. A phylogenetic analysis of the partial M (300 bp) and S (around 485 bp) genomes of HTN viruses identified nine distinct genetic subtypes, one consisting of isolates from Korea. The SEO viruses were divided into five genetic subtypes, although they had less variability than the HTN subtypes. There was a correlation between the subtype and province of origin for four subtypes of HTN viruses, confirming geographical clustering. Hantaan virus NC167 isolated from Niviventer confucianus and SEO virus Gou3 isolated from Rattus rattus were the basal clades in each virus. The phylogenetic trees constructed from the entire S and M segments suggested that NC167 was introduced to N. confucianus in a host-switching event. The reactivity of a panel of 35 monoclonal antibodies was almost exactly the same in NC167 and a representative HTN virus and in Gou3 and a representative SEO virus. However, there was a one-way cross-neutralization between them. These results confirm the varied nature of Murinae-associated hantaviruses in China.

Animals↗
PubMed2000

Mice lacking renal chloride channel, CLC-5, are a model for Dent's disease, a nephrolithiasis disorder associated with defective receptor-mediated endocytosis.

Nephrolithiasis (kidney stones) affects 5-10% of adults and is most commonly associated with hypercalciuria, which may be due to monogenic renal tubular disorders. One such hypercalciuric disorder is Dent's disease, which is characterized by renal proximal tubular defects that include low molecular weight proteinuria, aminoaciduria and glycosuria, together with rickets in some patients. Dent's disease is due to inactivating mutations of the renal-specific voltage-gated chloride channel, CLC-5, which is expressed in the proximal tubule, thick ascending limb and collecting duct. The subcellular localization of CLC-5 to the proximal tubular endosomes has suggested a role in endocytosis, and to facilitate in vivo investigations of CLC-5 in Dent's disease we generated mice lacking CLC-5 by targeted gene disruption. CLC-5-deficient mice developed renal tubular defects which included low molecular weight (<70 kDa) proteinuria, generalized aminoaciduria that was more pronounced for neutral and polar amino acids, and glycosuria. They also developed hypercalciuria and renal calcium deposits and some had deformities of the spine. Furthermore, endocytosis as assessed by horseradish peroxidase uptake in the proximal tubule was severely impaired in CLC-5-deficient mice, thereby demonstrating a role for CLC-5 in endosomal uptake of low molecular weight proteins. Thus, CLC-5-deficient mice provide a model for Dent's disease and this will help in elucidating the function of this chloride channel in endocytosis and renal calcium homeostasis.

Animals↗
PubMed2000

Hepatocyte nuclear factor 4alpha regulates the expression of pancreatic beta -cell genes implicated in glucose metabolism and nutrient-induced insulin secretion.

Mutations in the HNF4alpha gene are associated with the subtype 1 of maturity-onset diabetes of the young (MODY1), which is characterized by impaired insulin secretory response to glucose in pancreatic beta-cells. Hepatocyte nuclear factor 4alpha (HNF4alpha) is a transcription factor critical for liver development and hepatocyte-specific gene expression. However, the role of HNF4alpha in the regulation of pancreatic beta-cell gene expression and its correlation with metabolism secretion coupling have not been previously investigated. The tetracycline-inducible system was employed to achieve tightly controlled expression of both wild type (WT) and dominant-negative mutant (DN) of HNF4alpha in INS-1 cells. The induction of WT-HNF4alpha resulted in a left shift in glucose-stimulated insulin secretion, whereas DN-HNF4alpha selectively impaired nutrient-stimulated insulin release. Induction of DN-HNF4alpha also caused defective mitochondrial function substantiated by reduced [(14)C]pyruvate oxidation, attenuated substrate-evoked mitochondrial membrane hyperpolarization, and blunted nutrient-generated cellular ATP production. Quantitative evaluation of HNF4alpha-regulated pancreatic beta-cell gene expression revealed altered mRNA levels of insulin, glucose transporter-2, L-pyruvate kinase, aldolase B, 2-oxoglutarate dehydrogenase E1 subunit, and mitochondrial uncoupling protein-2. The patterns of HNF4alpha-regulated gene expression are strikingly similar to that of its downstream transcription factor HNF1alpha. Indeed, HNF4alpha changed the HNF1alpha mRNA levels and HNF1alpha promoter luciferase activity through altered HNF4alpha binding. These results demonstrate the importance of HNF4alpha in beta-cell metabolism-secretion coupling.

Adenosine Triphosphate↗
PubMed2000

Pharmacology of the receptors for the phorbol ester tumor promoters: multiple receptors with different biochemical properties.

The phorbol ester tumor promoters and related analogs are widely used as potent activators of protein kinase C (PKC). The phorbol esters mimic the action of the lipid second messenger diacylglycerol (DAG). The aim of this commentary is to highlight a series of important and controversial concepts in the pharmacology and regulation of phorbol ester receptors. First, phorbol ester analogs have marked differences in their biological properties. This may be related to a differential regulation of PKC isozymes by distinct analogs. Moreover, it seems that marked differences exist in the ligand recognition properties of the C1 domains, the phorbol ester/DAG binding sites in PKC isozymes. Second, an emerging theme that we discuss here is that phorbol esters also target receptors unrelated to PKC isozymes, a concept that has been largely ignored. These novel receptors lacking kinase activity include chimaerins (a family of Rac-GTPase-activating proteins), RasGRP (a Ras exchange factor), and Unc-13/Munc-13 (a family of proteins involved in exocytosis). Unlike the classical and novel PKCs, these "non-kinase" phorbol ester receptors possess a single copy of the C1 domain. Interestingly, each receptor class has unique pharmacological properties and biochemical regulation. Lastly, it is well established that phorbol esters and related analogs can translocate each receptor to different intracellular compartments. The differential pharmacological properties of the phorbol ester receptors can be exploited to generate specific agonists and antagonists that will be helpful tools to dissect their cellular function.

Animals↗
PubMed2000

Scale-up study on suspension cultures of Taxus chinensis cells for production of taxane diterpene.

Suspension cells of Taxus chinensis were cultivated in both shake flasks and bioreactors. The production of taxuyunnanine C (TC) was greatly reduced when the cell cultures were transferred from shake flasks to bioreactors. Oxygen supply, shear stress and stripping-off of gaseous metabolites were considered as potential factors affecting the taxane accumulation in bioreactors. The effects of oxygen supply on the cell growth and metabolism were investigated in a stirred tank bioreactor by altering its oxygen transfer rate (OTR). It was found that both the pattern and amount of TC accumulation were not much changed within the range of OTR as investigated. Comparative studies on the cell cultivation in low shear and high shear generating bioreactors suggest that the decrease of TC formation in bioreactors was not due to the different shear environments in different cultivation vessels. An incorporation of 2% CO(2) in the inlet air was beneficial for the cell growth, but did not improve the TC production in bioreactors. Furthermore, the effects of different levels of ethylene addition into the inlet air on the cell growth and TC production were investigated in a bubble column reactor. The average cell growth rate increased from 0.146 to 0.204 d(-1) as the ethylene concentration was raised from 0 to 50 ppm, and both the content and production of TC were also greatly improved by ethylene addition. At an ethylene concentration of 18 ppm, the highest TC content and volumetric production in the reactor reached 13.28 mg/(g DW) and 163.7 mg/L, respectively, which were almost the same as those in shake flasks. Compared with the control reactor (bubble column without ethylene supplementation), the maximum TC content was increased by 82% and the total production of TC was doubled. The results indicate that ethylene is a key factor in scaling up the process of the suspension cultures of T. chinensis from a shake flask to a bioreactor.

Journal Article↗