Biomedical subjects

Hong Cheng

Publications and source records attributed to Hong Cheng.

70 records · Page 4Linked to original sources

PubMed2004

Effect of puerarin on neural function and histopathological damages after transient spinal cord ischemia in rabbits.

OBJECTIVE: To investigate the effect of puerarin on the neural function and the histopathological changes after ischemic spinal cord injury in rabbits. METHODS: Thirty male New Zealand white rabbits were randomly divided into three groups as follows: puerarin group (n=10) receiving intravenous infusion of 30 mg/kg puerarin for 10 minutes, control group (n=10) receiving intravenous infusion of the same volume of normal saline as puerarin for 10 minutes, and sham operation group (n=10) undergoing only the surgical exposure of the abdominal aorta. Temporary spinal cord ischemia was induced by infrarenal aortic occlusion for 20 minutes and followed by reperfusion. The neural status was scored with the Tarlov criteria at 8, 12, 24 and 48 hours after reperfusion. All the animals were killed at 48 hours after reperfusion and the spinal cords (L5) were removed immediately for histopathological study. RESULTS: The neural function scores at 8, 12, 24 and 48 hours after reperfusion were higher in the puerarin group and sham operation group than those in the control group (P<0.05). More normal motor neurons in the anterior horn of spinal cord were present in the puerarin group and sham operation group than those in the control group (P<0.01). There was a strong correlation between the final neural function scores and the number of normal motor neurons in the anterior horn of spinal cord (r=0.839, P<0.01). CONCLUSIONS: Puerarin can significantly ameliorate the neural function and the histopathological damages after transient spinal cord ischemia in rabbits.

Animals↗

PubMed2004

[Ponderal index at birth predicts metabolic syndrome in mid-aged Chinese].

OBJECTIVE: To examine the association between Ponderal index (PI) at birth and metabolic syndrome during middle age. METHODS: Totally, 975 adults (494 men and 481 women) aged 41-52 from the study cohort of Fetal Origin of Adult Disease were recruited in the study for clinic examinations, involving anthropometry and measurements of blood pressure, fasting and 2 hr plasma levels of glucose and insulin, serum lipid profile. Their HOMA-insulin resistance (IR) index was estimated. Metabolic syndrome (MS) was diagnosed according to 1999 WHO definition. Multivariate logistic regression analysis was used to estimate the effect of PI on MS and the interaction between PI at birth and body mass index (BMI) in adulthood. RESULTS: Prevalence of MS was 18.7% in this mid-aged population, 24.8%, 19.4%, 16.3% and 14.0% in those with less than the 25th percentile, the 25th to less than the 50th percentile, the 50th to less than the 75th percentile and more than 75th percentile of PI at birth, respectively, in a decreasing trend (chi2 M-H for trend=9.938 adjusted for gender, P=0.002). Logistic regression analysis showed that both PI at birth and BMI during adulthood could influence their occurrence of MS (beta=-0.125, P=0.002, for PI; and beta=0.430, P=0.000, for BMI). A synergistic effect between PI at birth and BMI in adulthood was observed in this population. Persons who were thin at birth with PI less than the 25th percentile, and became overweight with BMI greater than or equal to 24 kg/m2 later in their life, were at higher risk of suffering from metabolic syndrome (OR=29.1, 95% CI=13.6-62.1), in comparison with those who became overweight during adulthood from a higher PI at birth (OR=16.0, 95% CI=7.9-32.3) and those who were thin at birth and remained a appropriate BMI during their adulthood (OR=2.0, 95% CI=0.7-5.7). Attributable fraction of the interaction to MS was 34.6%. CONCLUSIONS: Thin at birth was a predictor for later occurrence of metabolic syndrome, as well as an effect modifier for the association between of later BMI and metabolic syndrome, i.e., overweight later in his life was most deleterious for a person with growth retardation at birth.

Adult↗

PubMed2004

Polymorphisms of exon 17 of insulin-receptor gene in pathogenesis of human disorders with insulin resistance.

OBJECTIVE: To investigate the relationship between polymorphisms of insulin-receptor (INSR) gene and insulin resistance in a population-based study in China. METHODS: Polymerase Chain Reaction (PCR) was used to the amplify Exon 17 of INSR gene and all amplified products were analyzed by direct sequencing. RESULTS: Six single-nucleotide polymorphisms (SNPs) were found at the following loci: T to TC at the locus of 10699 (Tyr(984)), G to GC at the locus of 10731 (Glu(994)), Deletion G at the locus of 10798 (Asp(1017)), C to T/TC at the locus of 10923 (His(1058)), C to CA at the locus of 10954 (Leu(1069)), and T to TA at the locus of 10961 (Phe(1071)), which might not change the amino acid sequence. The data were in agreement with the test of Hardy-Weinberg balance (P > 0.05). Among the 345 cases, all clinical indices were higher in males than in females except for HDL cholesterol (P < 0.05). The proportion of insulin resistance in males (64.4%) was higher than that in females (35.6%, OR = 1.83). It implied that the relative risk of developing insulin resistance in males was 1.83 times as high as that in females. The biochemical indices in different loci on Exon 17 showed that the individuals with deletion G on the locus of 10798 had lower TG (P = 0.052) and higher HDL (P = 0.027) than those without deletion G on the same site. Homa-Index was lower in those with deletion G than in those without deletion G (P > 0.05). After sex stratification in analysis, all allele frequencies on the six loci of SNPs of Exon 17 had different distributions between the insulin resistant group and the control group, but P > 0.05. CONCLUSION: SNPs of Exon 17 of INSR gene are unlikely to play a direct role in the pathogenesis of human disorders with insulin resistance.

Amino Acid Sequence↗

PubMed2003

NMR-detected hydrogen exchange and molecular dynamics simulations provide structural insight into fibril formation of prion protein fragment 106-126.

PrP106-126, a peptide corresponding to residues 107-127 of the human prion protein, induces neuronal cell death by apoptosis and causes proliferation and hypertrophy of glia, reproducing the main neuropathological features of prion-related transmissible spongiform encephalopathies, such as bovine spongiform encephalopathy and Creutzfeldt-Jakob disease. Although PrP106-126 has been shown to form amyloid-like fibrils in vitro, their structural properties have not been elucidated. Here, we investigate the conformational characteristics of a fibril-forming fragment of the mouse prion protein, MoPrP106-126, by using electron microscopy, CD spectroscopy, NMR-detected hydrogen-deuterium exchange measurements, and molecular dynamics simulations. The fibrils contain approximately 50% beta-sheet structure, and strong amide exchange protection is limited to the central portion of the peptide spanning the palindromic sequence VAGAAAAGAV. Molecular dynamics simulations indicate that MoPrP106-126 in water assumes a stable structure consisting of two four-stranded parallel beta-sheets that are tightly packed against each other by methyl-methyl interactions. Fibril formation involving polyalanine stacking is consistent with the experimental observations.

Animals↗

PubMed2003

[Synergetic role of CD3epsilon and 5-fluorouracil in T Lymphocyte apoptosis and P53 expression].

OBJECTIVE: To investigate the relationship between apoptosis induced by CD3epsilon and 5-fluorouracil (5-FU), and study the P53 expression in the apoptosis process provide a novel insight and useful information of the apoptosis signaling pathway induced by CD3epsilon and/or 5-FU, and an important implication for the treatment of T-lymphocyte leukemia. METHODS: The viabilities of Jurkat T lymphocytes (JK), TJK [JK with over-expression of the CD8epsilon chimeria molecule] and T3JK [JK with over-expression of the CD8epsilon (Y170F/Y181F) mutation molecule] cells were cultured and treated with pre-coated anti-CD8 mAb (200 micro g/ml) and/or 5-FU (2.5 micro g/ml) were detected with MTS assay and the apoptosis percentages were calculated. Western blot was used to detect P53 expression. To confirm the role of P53 in 5-FU-treated T lymphocytes, pCMV-p53 plasmid with wild type or mutant p53 were co-transfected transiently with pEGFP-c1 into TJK and T3JK cells, respectively. RESULTS: CD3epsilon or 5-FU induced apoptosis of TJK with increase of P53 expression. Co-treatment with CD3epsilon specific antibody and 5-FU elevated the apoptotic rates and P53 expression in TJK cells remarkably. The cells transfected with wild-type p53 exhibited more sensitivity to 5-FU than that transfected with mutant p53. CONCLUSION: Co-treatment of CD3epsilon and 5-FU increases the apoptosis and p53 expression, suggesting that there is a synergetic role of CD3epsilon and 5-FU on T lymphocytes.

Apoptosis↗

PubMed2003

Structure, stability, and function of hDim1 investigated by NMR, circular dichroism, and mutational analysis.

The 142 amino acid Dim1p protein is a component of the U4/U6.U5 tri-snRNP complex required for pre-mRNA splicing and interacts with multiple splicing-associated proteins. To gain further insight into the structural basis of its function, we determined the solution structure of the reduced form of the dominant negative human hDim1 (hDim1(1)(-)(128)) using multidimensional NMR spectroscopy. This dominant negative hDim1 assumes a thioredoxin-like fold, confirming previous NMR and crystallographic results. However, in contrast to a recent crystal structure, the NMR solution structure for the reduced form of hDim1(1)(-)(128) presented here, along with thermodynamic data, indicates that the presence of a disulfide bond between Cys38 and Cys79 is structurally and functionally unimportant. Comparison of the truncated hDim1(1)(-)(128) with the full-length protein, using NMR and circular dichroism spectroscopy, indicates that the 14 C-terminal residues can undergo a local unfolding transition and assume alternative conformations, which appear to play a functional role. Other residues essential for hDim1 function are identified by using mutational and genetic approaches. The residues thus identified are not identical with those previously shown to govern Dim1 interaction with defined protein partners.

Alanine↗

PubMed2003

Expression of RNase H of human hepatitis B virus polymerase in Escherichia coli.

AIM: To amplify HBV-RNase H gene fragment and expression of RNase H for further use in the studies of HBV associated liver diseases. METHODS: The encoding gene of HBV-RNase H was separately amplified for the first half and second half (H1 and H2) by PCR from full length HBV gene and cloned into pT7Blue-T vector. Clones were first screened by digestion with XbaI and Hind III enzyme for the correct size, and analyzed further by DNA sequencing. The RNase H1 and H2 fragments isolated from XbaI and Hind III digestion products of pT7 Blue-RNase H plasmid were ligated to the GSTag expressing vectors separately, and expressed in E.coli BL21. The expressed proteins were checked by PAGE gel and Western blot. RESULTS: Both H1 and H2 nucleotide seqences consisting of known genes and proteins, in correct size, were further confirmed by Western blot to be the GST and RNase H1 or H2 fusion proteins. CONCLUSION: The successful cloning and expression of HBV-RNase H will contribute to further research and application in HBV-associated diseases.

DNA-Directed DNA Polymerase↗

PubMed2003

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma in gastroscopic biopsy.

AIM: To explore and discuss the clinicopathologic characteristics of mucosa-associated lymphoid tissue (MALT) lymphoma in gastroscopic biopsy specimen. METHODS: A retrospective study of 26 cases of lymphoma diagnosed by gastroscopic biopsy during 1999 to 2001 from gastroscopy files of Xijing Hospital was made. The diagnostic criteria were adopted according to the new classification of non-Hodgkin's lymphoma. RESULTS: Twenty-six cases of primary gastric lymphoma consisting of 15 men and 11 women, aged between 23 to 76 years were recruited from 6 225 cases who received gastroscopy. All of them were diagnosed by both endoscopic findings and histological examinations. Histologically, 23 cases were MALToma (low grade) and 3 cases lymphoblastic lymphoma (high grade). Immunohistochemically, all cases were CD20 positive, while CK and EMA were negative. CONCLUSION: The majority of the cases of primary low-grade gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa associated lymphoid tissue.

Adult↗

PubMed2003

[Prevalence of vitamin A deficiency in children under six years of age in Tibet, China].

OBJECTIVE: To understand the prevalence of vitamin A deficiency (VAD) among children under six years of age in Tibet, China. METHODS: Totally, 1 257 children under six years of age were selected from two cities, two farming counties, two semi-farming counties and two livestock farming counties with stratified cluster sampling to asses VAD status in Tibet. Family information, children's feeding and disease history in the previous two weeks were collected by questionnaire. Blood specimen was collected from each child and serum was separated for detection of vitamin A concentration with microfluorescent spectrophotometry. RESULTS: Totally, 1 257 children under six years of age were surveyed, with 635 boys, 622 girls, 862 aged over two years, and 98.5% of Tibet nationality. Six cases of night blindness and two cases of xerophthalmia were detected from them, with prevalence of clinical VAD of 0.96%. Eighteen of 1071 mothers with children under six years of age were found suffering from night blindness, accounting for 1.7%. Clinical cases of VAD both in children and mothers came from all four sampling strata. Average serum concentration of vitamin A and prevalence of subclinical VAD (serum vitamin A lower than or equal to 0.70 micromol/L) was 1.15 micromol/L and 5.4% and 1.12 micromol/L and 4.7% in cities and livestock farming counties, respectively, significantly higher than those in farming (1.04 micromol/L and 11.0%) and semi-farming counties (1.05 micromol/L and 12.3%), respectively, as compared to average levels of 1.09 micromol/L and 8.4% in the autonomous region as a whole. Prevalence of subclinical VAD in children under six months and those aged six to eleven months were 22.2% and 13.3%, respectively, significantly higher than those in children aged one year (8.5%), two to three years (5.4%) and four to five years (7.9%), respectively. There was also significant difference in serum level of vitamin A between children at varied ages, but no significant difference both in serum level of vitamin A and prevalence of subclinical VAD between gender was found. CONCLUSIONS: In general, status of VAD in children of Tibet was milder than that at national level. But, moderate subclinical VAD in some areas, such as farming and semi-farming counties, did exist, so vitamin A supplementation aiming to children, especially those under one year of age, in those areas should be urged.

Age Factors↗

PubMed2002

[Gastroenterology].

Explore the source record for details and available documents.

Biomedical Research↗

PubMed2002

Mapping the epitope of an inhibitory monoclonal antibody to the C-terminal DNA-binding domain of HIV-1 integrase.

Integrase (IN) catalyzes the insertion of retroviral DNA into chromosomal DNA of a host cell and is one of three virus-encoded enzymes that are required for replication. A library of monoclonal antibodies against human immunodeficiency virus type 1 (HIV-1) IN was raised and characterized in our laboratory. Among them, monoclonal antibody (mAb) 33 and mAb32 compete for binding to the C-terminal domain of the HIV-1 IN protein. Here, we show that mAb33 is a strong inhibitor of IN catalytic activity, whereas mAb32 is only weakly inhibitory. Furthermore, as the Fab fragment of mAb32 had no effect on IN activity, inhibition by this mAb may result solely from its bivalency. In contrast, Fab33 did inhibit IN catalytic activity, although bivalent binding by mAb33 may enhance the inhibition. Interaction with Fab33 also prevented DNA binding to the isolated C-terminal domain of IN. Results from size-exclusion chromatography, gel electrophoresis, and matrix-assisted laser desorption ionization time-of-flight mass spectrometric analyses revealed that multiple Fab33 small middle dotIN C-terminal domain complexes exist in solution. Studies using heteronuclear NMR showed a steep decrease in (1)H-(15)N cross-peak intensity for 8 residues in the isolated C-terminal domain upon binding of Fab33, indicating that these residues become immobilized in the complex. Among them, Ala(239) and Ile(251) are buried in the interior of the domain, whereas the remaining residues (Phe(223), Arg(224), Tyr(226), Lys(244), Ile(267), and Ile(268)) form a contiguous, solvent-accessible patch on the surface of the protein likely including the epitope of Fab33. Molecular modeling of Fab33 followed by computer-assisted docking with the IN C-terminal domain suggested a structure for the antibody-antigen complex that is consistent with our experimental data and suggested a potential target for anti-AIDS drug design.

Alanine↗

PubMed2002

Calcineurin is implicated in the regulation of the septation initiation network in fission yeast.

BACKGROUND: In fission yeast, calcineurin has been implicated in cytokinesis because calcineurin-deleted cells form multiple septa and cell separation is impeded. However, this mechanism remains unclear. RESULTS: We screened for mutations that confer synthetic lethality with calcineurin deletion and isolated a mutant, its 10-1/cdc7-i10, a novel allele of the cdc7+ gene involved in the septation initiation network (SIN). The mutation created a termination codon, resulting in the truncation of Cdc7 by 162 amino acids, which is not localized in the spindle pole body. Following treatment with the immune suppressive drug FK506, cdc7-i10 and the original cdc7-24 mutant cells showed highly elongated multinuclear morphology with few visible septa, closely resembling the phenotype at the restrictive temperature. Other SIN mutants, cdc11, spg1, sid2 and mob1 showed similar phenotypes following FK506 treatment. Consistent with this, expression of the constitutively active calcineurin suppressed the growth defects and septum initiation deficiency of these SIN mutants at the restrictive temperature. Moreover, electron microscopy revealed that calcineurin-deleted cells had very thick multiple septa which were partially and ectopically formed. CONCLUSION: These results suggest that calcineurin is involved in the regulation of the SIN pathway, and is required for the proper formation and maturation of the septum in fission yeast.

Alleles↗

PubMed2002

Role of the Rab GTP-binding protein Ypt3 in the fission yeast exocytic pathway and its connection to calcineurin function.

A genetic screen for mutations synthetically lethal with fission yeast calcineurin deletion led to the identification of Ypt3, a homolog of mammalian Rab11 GTP-binding protein. A mutant with the temperature-sensitive ypt3-i5 allele showed pleiotropic phenotypes such as defects in cytokinesis, cell wall integrity, and vacuole fusion, and these were exacerbated by FK506-treatment, a specific inhibitor of calcineurin. Green fluorescent protein (GFP)-tagged Ypt3 showed cytoplasmic staining that was concentrated at growth sites, and this polarized localization required the actin cytoskeleton. It was also detected as a punctate staining in an actin-independent manner. Electron microscopy revealed that ypt3-i5 mutants accumulated aberrant Golgi-like structures and putative post-Golgi vesicles, which increased remarkably at the restrictive temperature. Consistently, the secretion of GFP fused with the pho1(+) leader peptide (SPL-GFP) was abolished at the restrictive temperature in ypt3-i5 mutants. FK506-treatment accentuated the accumulation of aberrant Golgi-like structures and caused a significant decrease of SPL-GFP secretion at a permissive temperature. These results suggest that Ypt3 is required at multiple steps of the exocytic pathway and its mutation affects diverse cellular processes and that calcineurin is functionally connected to these cellular processes.

Actins↗

PubMed2002

Cancer incidence among triazine herbicide manufacturing workers.

This study evaluated cancer incidence and prostate specific antigen (PSA) testing among workers at a plant in Louisiana (LA) that made atrazine and other triazine herbicides. The study covered the time period 1985 through 1997 and included 2045 subjects, of whom 757 worked for the company that owned the plant and 1288 were contract employees. Linkage with a population-based cancer registry and review of death certificates and plant medical records identified cancer cases. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) compared subjects' cancer incidence rates with those of a regional general population. Plant medical records provided data on the proportion receiving PSA tests among male company employees. Subjects had 46 observed and 40 expected cases of all cancers combined (SIR = 114, CI = 83-152) and had 11/6.3 prostate cancers (SIR = 175, CI = 87-312). The prostate cancer excess was greater in actively working company employees (5/1.3, SIR = 394, CI = 128-920) than in contract employees or inactive company employees (6/5.0, SIR = 119, CI = 44-260) and was limited to men under 60 years of age. Of the 11 prostate cancer cases, nine were diagnosed at an early clinical stage. From 1993 to 1999, the proportion of male company employees who had at least one PSA test was 86% for those who reached 40 years of age while actively working and was 98% for those who reached 45 years of age. The observed prostate cancer increase may have been due to the frequent PSA testing of actively working company employees. There is no epidemiologic or other information that clearly supports a causal relation between atrazine and prostate cancer.

Adult↗

PubMedDate not supplied

5-Fluorouracil enhances apoptosis sensitivity of T lymphocytes mediated by CD3 epsilon.

Previous studies by our laboratory have reported that the T cell receptor (TCR) TCR/CD3 complex could mediate activation as well as apoptosis of T lymphocytes. Two tyrosine residues in the ITAM (immuno-receptor tyrosine-based activation motifs) of CD3 epsilon were required for apoptosis signalling of Jurkat T lymphocytes. Stable cell lines TJK and T3JK produced from CD8(-) Jurkat T lymphocytes by transfection with wild-type and mutant CD8 epsilon (fusion of the extracellular and transmembrane domains of human CD8 alpha to the intracellular domain of mouse CD3 epsilon), were used with CD8(-) Jurkat T lymphocytes for studying the role of single intact CD3 epsilon. 5-Fluorouracil (5-FU), a chemotherapeutic drug can induce cell death of many tumour cell lines. In the present experiments, we examined the expression of caspase-3, p53 and Bid in the three cell lines induced by 5-FU and/or anti-CD8 antibody. We found high expression of p53 during activation-induced cell death of TJK cells mediated by anti-CD8 antibody and apoptosis of TJK and T3JK induced by 5-FU, implicating p53 involvement in apoptosis of leukemia cells induced by anti-CD8 antibody and 5-FU. We also detected the active form of caspase-3 and Bid in apoptotic leukemia cells after treatment with 5-FU and/or anti-CD8 antibody, indicating that the drug and antibody induced cell death through caspase-3 and the signal pathway may involve the Bcl-2 protein family. Our results showed that combined treatment with 5-FU and anti-CD8 antibody could enhance the rate of apoptosis induced by 5-FU or anti-CD8 antibody through increased expression of p53 and by promoting activation of caspase-3 and Bid. This suggests that the combination of 5-FU and anti-CD8 antibody may play an important role in inducing apoptosis of leukemia cells.

Antibodies, Monoclonal↗

PubMedDate not supplied

The anatomy, affinity, and phylogenetic significance of Markuelia.

The fossil record provides a paucity of data on the development of extinct organisms, particularly for their embryology. The recovery of fossilized embryos heralds new insight into the evolution of development but advances are limited by an almost complete absence of phylogenetic constraint. Markuelia is an exception to this, known from cleavage and pre-hatchling stages as a vermiform and profusely annulated direct-developing bilaterian with terminal circumoral and posterior radial arrays of spines. Phylogenetic analyses have hitherto suggested assignment to stem-Scalidophora (phyla Kinorhyncha, Loricifera, Priapulida). We test this assumption with additional data and through the inclusion of additional taxa. The available evidence supports stem-Scalidophora affinity, leading to the conclusion that scalidophorans, cyclonerualians, and ecdysozoans are primitive direct developers, and the likelihood that scalidophorans are primitively metameric.

Animals↗