Biomedical subjects

Hui Sun

Publications and source records attributed to Hui Sun.

At least 91 records · Page 5Linked to original sources

PubMed2004

Trichostatin A extends the lifespan of Drosophila melanogaster by elevating hsp22 expression.

The level of acetylation of histones in nucleosomes is related to the longevity of yeast and animals. However, the mechanisms by which acetylation and deacetylation affect longevity remain unclear. In present study, we investigated the influence of histone acetylation modification on the expression of hsp22 gene and the lifespan in Drosophila melanogaster using histone deacetylase (HDAC) inhibitor Trichostatin A (TSA). The results showed that TSA could extend the lifespan of Drosophila melanogaster. Furthermore, TSA significantly promoted the hsp22 gene transcription, and affected the chromatin morphology at the locus of hsp22 gene along the polytene chromosome. Present data implicate that TSA may affect the lifespan of Drosophila through changing the level of histone acetylation and influencing the expression of hsp22 gene that is related to aging.

Acetylation↗

PubMed2004

Sequence and comparative analysis of the maize NB mitochondrial genome.

The NB mitochondrial genome found in most fertile varieties of commercial maize (Zea mays subsp. mays) was sequenced. The 569,630-bp genome maps as a circle containing 58 identified genes encoding 33 known proteins, 3 ribosomal RNAs, and 21 tRNAs that recognize 14 amino acids. Among the 22 group II introns identified, 7 are trans-spliced. There are 121 open reading frames (ORFs) of at least 300 bp, only 3 of which exist in the mitochondrial genome of rice (Oryza sativa). In total, the identified mitochondrial genes, pseudogenes, ORFs, and cis-spliced introns extend over 127,555 bp (22.39%) of the genome. Integrated plastid DNA accounts for an additional 25,281 bp (4.44%) of the mitochondrial DNA, and phylogenetic analyses raise the possibility that copy correction with DNA from the plastid is an ongoing process. Although the genome contains six pairs of large repeats that cover 17.35% of the genome, small repeats (20-500 bp) account for only 5.59%, and transposable element sequences are extremely rare. MultiPip alignments show that maize mitochondrial DNA has little sequence similarity with other plant mitochondrial genomes, including that of rice, outside of the known functional genes. After eliminating genes, introns, ORFs, and plastid-derived DNA, nearly three-fourths of the maize NB mitochondrial genome is still of unknown origin and function.

Base Sequence↗

PubMed2004

Phloridzin improves hyperglycemia but not hepatic insulin resistance in a transgenic mouse model of type 2 diabetes.

The chronic hyperglycemia that occurs in type 2 diabetes may cause deterioration of beta-cell function and insulin resistance in peripheral tissues. Mice that express a dominant-negative IGF-1 receptor, specifically in skeletal muscle (MKR mice), exhibit severe insulin resistance, hyperinsulinemia, dyslipidemia, and hyper-glycemia. To determine the role of hyperglycemia in the worsening of the diabetes state in these animals, MKR mice were treated with phloridzin (PHZ), which inhibits intestinal glucose uptake and renal glucose reabsorption. Blood glucose levels were decreased and urine glucose levels were increased in response to PHZ treatment in MKR mice. PHZ treatment also increased food intake in MKR mice; however, the fat mass was decreased and lean body mass did not change. Serum insulin, fatty acid, and triglyceride levels were not affected by PHZ treatment in MKR mice. Hyperinsulinemic-euglycemic clamp analysis demonstrated that glucose uptake in white adipose tissue was significantly increased in response to PHZ treatment. Despite the reduction in blood glucose following PHZ treatment, there was no improvement in insulin-stimulated whole-body glucose uptake in MKR mice and neither was there suppression of endogenous glucose production by insulin. These results suggest that glucotoxicity plays little or no role in the worsening of insulin resistance that occurs in the MKR mouse model of type 2 diabetes.

Adipose Tissue↗

PubMed2004

[Relationship between fibrinogen B beta gene FGB -455G/A polymorphism and atherosclerotic cerebral infarction].

OBJECTIVE: To explore the distribution of fibrinogen (FGB) B beta polymorphism in Chinese Han population and the association of the polymorphisms with the occurrence of atherosclerotic cerebral infarction (ACI). METHODS: The B beta gene FGB -455G/A polymorphism was identified by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) in 132 patients with ACI and 148 healthy controls matching on age and sex. Turbidimetric assays were performed to measure the plasma fibrinogen levels of all cases. RESULTS: The plasma fibrinogen level in ACI group (3.42+/-0.52 g/L), was significantly higher than that in the controls (2.96+/-0.42g/L), P<0.001. The A allele was associated with the elevated plasma fibrinogen levels in both patients and controls. Among the A allele carriers, smokers had significantly higher plasma fibrinogen levels than did the non-smokers (P<0.05). The distribution of B beta gene FGB -455G/A polymorphism was in accordance with the Hardy-Weinberg equilibrium (P>0.05). The A allelic frequency in ACI group (0.258) was significantly higher than that in the control group (0.152) (P<0.05). Logistic regression analysis showed that the cases carrying A allele (GA+AA genotype) had 1.653 times the risk of ACI. CONCLUSION: The study demonstrates that A allele of the B beta gene FGB -455G/A polymorphism may be a susceptible predictor of the occurrence of ACI, particularly in smokers.

Aged↗

PubMed2004

[CXCR4 expression in B-lineage acute lymphocyte leukemia and its significance].

The study was aimed to explore the chemokine receptor CXCR4 expression on the B-lineage acute lymphocyte leukemia (B-ALL) cells of various differentiation stages and its relationship with myeloid antigen expression. Flow cytometry was used to detect the CXCR4 expression by means of double-fluorescence labeling with CD19/SCC gating. The results demonstrated that 92.9% B-ALL patients were positively expressed CXCR4. The CD10, CD34 antigens were differently expressed in differentiation stages of B-ALL. The immunotypes of (1) CD10(-)/CD34(+), (2) CD10(+)/CD34(+), (3) CD10(+)/CD34(-), (4) CD10(-)/CD34(-) presented at various differential stages from premature to mature. The positive rate of CXCR4 were (27.60 +/- 15.25)%, (30.95 +/- 15.50)%, (55.62 +/- 18.37)% and (77.25 +/- 10.86)% from (1) to (4) respectively. The median fluorescence intensity (MFI) of CXCR4 expression were 46.69 +/- 15.06, 47.43 +/- 12.39, 79.28 +/- 24.71 and 132.92 +/- 88.09. CXCR4 expressions were not significantly different between the premature stages of CD10(-)/CD34(+) and CD10(+)/CD34(+) subtypes, but both were lower than the CXCR4 expression in CD10(+)/CD34(-) and CD10(-)/CD34(-) subtypes. The highest incidence of CXCR4 expression was found in CD10(-)/CD34(-) B-ALL. The average level of CXCR4 expression on B-ALL cell with positive myeloid antigen CD13 or/and CD33 (my(+)B-ALL) was (12.56 +/- 3.88)% of positive rate and 39.82 +/- 11.58 of MFI, both of which were less than the positive rate (37.57 +/- 11.59)% and the MFI (50.72 +/- 13.34) on B-ALL cells with negative myeloid antigen expression (mye(-)B-ALL). In conclusion, the CXCR4 expression is associated with differentiation level of B-ALL cells and down-regulated when co-expressed with myeloid antigens.

Adolescent↗

PubMed2004

[Preliminary research on the effect of antisense oligodeoxynucleotides of tankyrase 1 on tumor growth following intratumoral injection in mice].

OBJECTIVE: To observe the suppressing effect of antisense oligodeoxynucleotides of tankyrase 1 (TANK1-ASODN) on murine tumor growth following intratumoral injection, and to explore its potential use in clinical treatment of lung cancer. METHODS: After human lung cancer cells CALU had been inoculated subcutaneously to BALB/c nude mice and grew to tumor nodules, these mice were distributed randomly into three groups: four in the saline group, five in the TANK1-ASODN group, and another five in the sense oligodeoxynucleotides of tankyrase (TANK1-SODN) group. Multiple direct intratumoral injections of TANK1-ASODN, TANK1-SODN or saline were given into the tumor nodules, respectively. The tumor growth and the histopathological characteristics were observed and the expression of ki67 and telomerase hTERT in tumor cells were measured by SABC immunohistrochemical method. RESULTS: After 16 days of continuous injection, the tumor volume of the TANK1-ASODN group was significantly smaller than that of the TANK1-SODN (P < 0.01) and saline-treated groups (P < 0.01); tumor cell degeneration and necrosis were observed in mice treated with TANK1-ASODN. Moreover, a statistically significant decrease in Ki67 labeling index (P < 0.01) and the positive expression ratio of telomerase hTERT (P < 0.01) was observed in the TANK1-ASODN group. CONCLUSIONS: Human lung tumor cell lines express high telomerase activity. TANK1-ASODN can inhibit the activity of telomerase and suppress the proliferation of tumor cells.

Animals↗

PubMed2004

[Influence of gentian leaf blight on the output and quality of Chinese gentian].

OBJECTIVE: To study the influecnce of gentian leaf blight on the output and quality of rough gentian. METHOD: The same grade seedlings were transplanted, disease of every plant was investigated in autumn and the output of gentian was determined. HPLC was applied to determine the content of gentiopicroside and swertiamarin. RESULT: The output decreased with the aggravation of the disease, and the decrease was obvious when the index of disease was above 60. The content of gentiopicroside and swertiamarin began to drop when the index of disease was above 70. CONCLUSION: The loss of output and the drop of quality are relatively heavy when the disease is serious. The loss of income is not obvious when the index of disease is under 60.

Gentiana↗

PubMed2004

[Treatment of delayed complex malhealed jaw fractures in 32 patients.].

PURPOSE: Three methods were used to manage delayed complex malhealed jaw fractures in 32 patients. The indication for each method and final result was evaluated. METHODS: Three methods included conservative therapy, internal fixation and orthognathic surgery. In conservative therapy, intermaxillary fixation was obtained with dental arch splints. In internal fixation, ordinary operation was performed including open exposure of the fractured segments, anatomical reposition and rigid fixation with steel wire or titanium miniplates. In some patients, orthognathic surgery was carried out with intermaxillary ligation for 2 to 3 weeks postoperatively. RESULTS: All the wounds healed primarily without significant complications. The postoperative occlusion and appearance were satisfactory or fair. CONCLUSIONS: The selection of treatment methods should be based on the location, time, severity of the fracture and the patients' age, in order to achieve maximal recovery of mastication and appearance.

Dental Occlusion↗

PubMed2003

Direct activation by dopamine of recombinant human 5-HT1A receptors: comparison with human 5-HT2C and 5-HT3 receptors.

The effects of dopamine (DA) on the function of human 5-HT1A receptors expressed in Xenopus oocytes and CHO-K1 cells were investigated. In addition, the effect of DA on the activation of three different types of human 5-HT receptors (5-HT1A, 5-HT2C, and 5-HT3) were studied comparatively in Xenopus oocyte expression system. Application of 5-HT or DA in oocytes coexpressing 5-HT1A receptors and G-protein-activated inwardly rectifying potassium channels (GIRK1) induced inward currents with respective EC50 values of 4.2 nM and 11.2 microM. Maximal responses induced by DA were 85 +/- 4% of maximal 5-HT currents and DA responses were blocked by the specific 5-HT1A antagonist, WAY-100635 (50 nM). In CHO-K1 cells expressing 5-HT1A receptors, 5-HT and DA inhibited the specific binding of selective antagonist [3H]-8-OH-DPAT with IC50 values of 10.2 nM and 1.4 microM, and both 5-HT and DA inhibited the forskolin-induced accumulation of cAMP. In oocytes expressing 5-HT2C receptors, 5-HT and DA induced inward currents with respective EC50 values of 6.2 nM and 67.7 microM. Magnitudes of maximal DA induced currents were 42 +/- 3% of maximal 5-HT responses and blocked by the 5-HT2 antagonist, piperazine (1 microM). In oocytes expressing 5-HT3 receptors, 5-HT and DA induced fast inward currents with respective EC50 values of 2.1 microM and 266.3 microM. Maximal DA induced currents were 37 +/- 3% of maximal 5-HT responses and blocked the specific 5-HT3 antagonist LY-278584 (0.1 microM). Comparison of the potencies and efficacies of 5-HT and DA indicated that the relative potency of DA increased in the order of 5-HT3 > 5-HT1A > 5-HT2C, and relative efficacy increased in the order of 5-HT1A > 5-HT2C > 5-HT3. These results suggest that although DA activates different subtypes of human 5-HT receptors directly, the potency and efficacy of the binding site varies significantly among different receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed2003

A pilot study of high-throughput, sequence-based mutational profiling of primary human acute myeloid leukemia cell genomes.

In this pilot study, we used primary human acute myeloid leukemia (AML) cell genomes as templates for exonic PCR amplification, followed by high-throughput resequencing, analyzing approximately 7 million base pairs of DNA from 140 AML samples and 48 controls. We identified six previously described, and seven previously undescribed sequence changes that may be relevant for AML pathogenesis. Because the sequencing templates were generated from primary AML cells, the technique favors the detection of mutations from the most dominant clones within the tumor cell mixture. This strategy represents a viable approach for the detection of potentially relevant, nonrandom mutations in primary human cancer cell genomes.

Case-Control Studies↗

PubMed2003

The Arabidopsis heterochronic gene ZIPPY is an ARGONAUTE family member.

Plants progress through a temporal sequence of juvenile, adult, and reproductive phases, each marked by the expression of phase-specific traits. Here we show that loss-of-function mutations in ZIPPY (ZIP) cause the premature expression of adult vegetative traits but do not accelerate the onset of reproductive competence or flowering time. ZIP encodes ARGONAUTE7 (AGO7), one of ten members of the ARGONAUTE family in Arabidopsis. In addition to playing developmental roles, some ARGONAUTE family members are required for RNAi-like phenomena, such as posttranscriptional gene silencing. In contrast to Arabidopsis ARGONAUTE1, ZIP has no significant role in transgene silencing; its primary function is in the regulation of developmental timing.

Arabidopsis↗

PubMed2003

An antitumour lectin from the edible mushroom Agrocybe aegerita.

An antitumour lectin (named AAL) consisting of two identical subunits of 15.8 kDa was isolated from the fruiting bodies of the edible mushroom Agrocybe aegerita using a procedure which involved precipitating the extract by addition of (NH(4))(2)SO(4), ion exchange chromatography on DEAE-Sepharose Fast Flow, gel filtration chromatography on Sephacryl S-200 HR and finally purification on a GF-250 HPLC column. Amino acid analysis of the N-terminus and an internal fragment indicated that the sequences of the two fragments were QGVNIYNI and Q(K)PDGPWLVEK(Q)R respectively. AAL showed strong inhibition of the growth of human tumour cell lines HeLa, SW480, SGC-7901, MGC80-3, BGC-823, HL-60 and mouse sarcoma S-180. AAL also inhibited the viability of S-180 tumour cells in vivo. Analysis by Hoechst 33258 staining, MitoSensor Kit and flow cytometry showed that AAL induced apoptosis in HeLa cells. TUNEL (terminal transferase deoxytidyl uridine end labelling) analysis of slides of tumour tissues excised from BALB/c mice also demonstrated the apoptosis-induction activity of the lectin. Furthermore, AAL was shown to possess DNase activity in assays using plasmid pCDNA3 and salmon sperm DNA. Based on the results obtained in these assays, we conclude that AAL exerts its antitumour effects via apoptosis-inducing and DNase activities.

Agaricales↗

PubMed2003

L-type Ca2+ channels provide a major pathway for iron entry into cardiomyocytes in iron-overload cardiomyopathy.

Under conditions of iron overload, which are now reaching epidemic proportions worldwide, iron-overload cardiomyopathy is the most important prognostic factor in patient survival. We hypothesize that in iron-overload disorders, iron accumulation in the heart depends on ferrous iron (Fe2+) permeation through the L-type voltage-dependent Ca2+ channel (LVDCC), a promiscuous divalent cation transporter. Iron overload in mice was associated with increased mortality, systolic and diastolic dysfunction, bradycardia, hypotension, increased myocardial fibrosis and elevated oxidative stress. Treatment with LVDCC blockers (CCBs; amlodipine and verapamil) at therapeutic levels inhibited the LVDCC current in cardiomyocytes, attenuated myocardial iron accumulation and oxidative stress, improved survival, prevented hypotension and preserved heart structure and function. Consistent with the role of LVDCCs in myocardial iron uptake, iron-overloaded transgenic mice with cardiac-specific overexpression of the LVDCC alpha1-subunit had twofold higher myocardial iron and oxidative stress levels, as well as greater impairment in cardiac function, compared with littermate controls; LVDCC blockade was again protective. Our results indicate that cardiac LVDCCs are key transporters of iron into cardiomyocytes under iron-overloaded conditions, and potentially represent a new therapeutic target to reduce the cardiovascular burden from iron overload.

Amlodipine↗

PubMed2003

Structure-function analysis of the bestrophin family of anion channels.

The bestrophins are a newly described family of anion channels unrelated in primary sequence to any previously characterized channel proteins. The human genome codes for four bestrophins, each of which confers a distinctive plasma membrane conductance on transfected 293 cells. Extracellular treatment with methanethiosulfonate ethyltrimethylammonium (MTSET) of a series of substitution mutants that eliminate one or more cysteines from human bestrophin1 demonstrates that cysteine 69 is the single endogenous cysteine responsible for MTSET inhibition of whole-cell current. Cysteines introduced between positions 78-99 and 223-226 are also accessible to external MTSET, with MTSET modification at positions 79, 80, 83, and 90 producing a 2-6-fold increase in whole-cell current. The latter set of four cysteine-substitution mutants define a region that appears to mediate allosteric control of channel activity. Mapping of transmembrane topography by insertion of N-linked glycosylation sites and tobacco etch virus protease cleavage sites provides evidence for cytosolic N and C termini and an unexpected transmembrane topography with at least three extracellular loops that include positions 60-63, 212-227, and 261-267. These experiments provide the first structural analysis of the bestrophin channel family.

Amino Acid Sequence↗

PubMed2003

The DNA sequence of human chromosome 7.

Human chromosome 7 has historically received prominent attention in the human genetics community, primarily related to the search for the cystic fibrosis gene and the frequent cytogenetic changes associated with various forms of cancer. Here we present more than 153 million base pairs representing 99.4% of the euchromatic sequence of chromosome 7, the first metacentric chromosome completed so far. The sequence has excellent concordance with previously established physical and genetic maps, and it exhibits an unusual amount of segmentally duplicated sequence (8.2%), with marked differences between the two arms. Our initial analyses have identified 1,150 protein-coding genes, 605 of which have been confirmed by complementary DNA sequences, and an additional 941 pseudogenes. Of genes confirmed by transcript sequences, some are polymorphic for mutations that disrupt the reading frame.

Animals↗

PubMed2003

Modulation of 5-HT3 receptor-mediated response and trafficking by activation of protein kinase C.

Modulation of neurotransmitter-gated membrane ion channels by protein kinase C (PKC) has been the subject of a number of studies. However, less is known about PKC modulation of the serotonin type 3 (5-HT3) receptor, a ligand-gated membrane ion channel that can mediate fast synaptic transmission in the central and peripheral nervous system. Here, we show that PKC potentiated 5-HT3 receptor-mediated current in Xenopus oocytes expressing 5-HT3A receptors and mouse N1E-115 neuroblastoma cells. In addition, using a specific antibody directed to the extracellular N-terminal domain of the 5-HT3A receptor, treatment with the PKC activator, 4 beta-phorbol 12-myristate 13-acetate (PMA), significantly increased surface immunofluorescence. PKC also increased the amount of 5-HT3A receptor protein in the cell membrane without affecting the amount receptor protein in the total cell extract. The magnitude of PMA potentiation of 5-HT3A receptor-mediated responses is correlated with the magnitude of PMA enhancement of the receptor abundance in the cell surface membrane. PMA potentiation is unlikely to occur via direct phosphorylation of the 5-HT3A receptor protein since the potentiation was not affected by point mutation of each of the putative sites for PKC phosphorylation. However, preapplication of phalloidin, which stabilizes the actin polymerization, significantly inhibited PMA potentiation of 5-HT-activated responses in both N1E-115 cells and oocytes expressing 5-HT3A receptors. On the other hand, latrunculin-A, which destabilizes actin cytoskeleton, enhanced the PMA potentiation of 5-HT3A receptors. The observations suggest that PKC can modulate 5-HT3A receptor function and trafficking through an F-actin-dependent mechanism.

Actins↗

PubMed2003

A lectin with mycelia differentiation and antiphytovirus activities from the edible mushroom Agrocybe aegerita.

A lectin named AAL has been purified from the fruiting bodies of the edible mushroom Agrocybe aegerita. AAL consisted of two identical subunits of 15.8 kDa, its pI was about 3.8 determined by isoelectric focusing, and no carbohydrate was discerned. Being treated by pyrogultamate aminopeptidase, the blocked N-terminus of AAL was sequenced as QGVNIYNI. AAL agglutinated human and animal erythrocytes regardless of blood type or animal species. Its hemagglutinating activity was unaffected by acid or alkali treatment and demetalization or addition of divalent metals Mg(2+), Ca(2+) and Zn(2+). AAL was toxic to mice: its LD50 was 15.85 mg per kilogram body weight by intraperitoneal injection. In this study, two novel activities of AAL were proved. It showed inhibition activity to infection of tobacco mosaic virus on Nicotiana glutinosa. The result of IEF suggested that AAL attached to TMV particles. Mycelia differentiation promotion was the other interesting activity. AAL promoted the differentiation of fruit body primordia from the mycelia of Agrocybe aegerita and Auricularia polytricha. AAL antiserum was prepared and immunologically cross-reactived with several proteins from five other kinds of mushrooms. These results suggested that AAL probably was a representative of a large protein family, which plays important physiological roles in mushroom.

Agaricales↗

PubMed2003

The DNA sequence and analysis of human chromosome 14.

Chromosome 14 is one of five acrocentric chromosomes in the human genome. These chromosomes are characterized by a heterochromatic short arm that contains essentially ribosomal RNA genes, and a euchromatic long arm in which most, if not all, of the protein-coding genes are located. The finished sequence of human chromosome 14 comprises 87,410,661 base pairs, representing 100% of its euchromatic portion, in a single continuous segment covering the entire long arm with no gaps. Two loci of crucial importance for the immune system, as well as more than 60 disease genes, have been localized so far on chromosome 14. We identified 1,050 genes and gene fragments, and 393 pseudogenes. On the basis of comparisons with other vertebrate genomes, we estimate that more than 96% of the chromosome 14 genes have been annotated. From an analysis of the CpG island occurrences, we estimate that 70% of these annotated genes are complete at their 5' end.

5' Untranslated Regions↗