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H Qiu

Publications and source records attributed to H Qiu.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Study on the differentiation and apoptosis of promyelocytic leukemia cells induced by tributyrin].

OBJECTIVE: To investigate the differentiation of NB4 and MR2 cells induced by tributyrin (TB) in combination with different doses of all-trans retinoic acid (ATRA) and to see if TB can induce apoptosis of NB4 and MR2 cells. METHODS: Cell differentiation was analyzed by NBT reduction and CD(11b), CD(14) and CD(33), apoptosis by morphology, DNA electrophoresis, flow cytometry (FCM) and TUNEL in situ hybridization, bcl-2 expression by reverse transcriptase polymerase chain reaction. RESULTS: 0.2 mmol/L TB in combination with different doses of ATRA could potentiate the differentiation of NB4 cells induced by ATRA alone. No MR2 cell could be markedly induced by ATRA alone or in combination with TB. Treated with 1 mmol/L TB for 24 hours NB4 and MR2 cells exhibited a morphological characteristic of apoptosis and typical DNA ladder on gel electrophoresis. FCM analysis showed that TB could interfere with cell cycle in NB4 and MR2 cells, with a similar ratio of sub-G(1) in both cell lines. TUNEL in situ hybridization confirmed these results. Further study showed that TB could gradually down-regulated bcl-2 expression. CONCLUSION: TB exerts synergetic effect on ATRA-induced differentiation and induces apoptosis in promyelocytic leukemic cells.

Apoptosis↗
PubMed2000

[The effect of heparin on mesangial cells proliferation and cytokines production].

The human glomerular mesangial cells(MC) proliferation and cytokines secretion were detected by using MTT method and biological active method so as to assess the effects of heparin on the cultured human glomerular MC induced by lipopolysaccharides (LPS). The results showed that there were basic production of interleukin-6(IL-6) and tumor necrosis factor-alpha (TNF-alpha) on MC in the control group without LPS, that high-concentration heparin(500 U/ml) increased the effects of LPS on MC, and that low-concentration heparin (5 U/ml) conversely inhibited the effects of LPS on MC. These data indicate that the low-concentration heparin could inhibit the proliferation of MC and the secrection of IL-6 and TNF-alpha induced by LPS, and hence provide an experimental evidence for administration of heparin in the treatment glomerular disease.

Cells, Cultured↗
PubMed2000

[Nucleotide sequence analysis of E2 major protective antigen encoding region of 12 strains of hog cholera virus(HCV)].

cDNA fragments, of HCV envelope glycoprotein E2 major gene of 11 field strains isolated in China in different time and 1 French reference strain(Thiveral) were amplified respectively with RT-PCR method and sequenced. The fragments amplified located by the 5' 2485 to 2708 of E2 major domains B and C and encoded 75 amino acid residues of E2 glycoprotein. All the products amplifield by RT-PCR from 12 strains in the study were same size of 224 bp. Comparing 12 sequences with other 9 references strains sequence reported before using software DNAstar, it was found that Hog Cholera Virus could be classified in two groups by analysis of phylogenetic tree. Strains Brescia, Gpe, Ald, Thiverval, C, CW, HCLV, HCVSM, BJCY1/96, BJTX3/96, BJSY2/96, HeNXH2/98, HeNZZ1/82 and GDGZ1/95 were assigned to group A and were 85.7%-100% for nucleotide sequence and 83.8%-100% for amino acid sequence in homology; but strains HCVF98, HCVF94, HeBHH2/95, LN1/84, SZGM1/85, SCCD1/79 and Alfort were assigned to group B and were 84.3%-100% for nucleotide sequence and 85.1%-100% for amino acid sequence in homology; and 21 strains of HCV were 78.1%-100% for nucleotide sequence and for 78.4%-100% amino acid sequence in homology. Homology were 99.1% for nucleotide sequence and 100% for amino acid sequence between strains HCLV in our study and strains C reported by Rijn's in the Netherlands. It's showed our method of sequencing is reliable. There were obvious differences between the two groups in sequences of envelope glycoprotein E2 major gene, especially in the amino acid substitutions of sites 713 and 729 respectively, and it is showed the two groups of HCV field strains might vary genetically in some extents. The results of other report of challenging of the partial field strains showed that the Chinese stock vaccine virus(HCLV) has good immunity.

Amino Acid Sequence↗
PubMed2000

[Surgical treatment of rectal villous adenomas: report of 49 cases].

OBJECTIVE: To evaluate surgical treatment of rectal villous adenomas. METHODS: Forty-nine cases of rectal villous adenomas treated with different surgical procedures were reviewed. Twenty (40.8%) of 49 patients had Mason's operation, eleven(22.4%) had Dixon's operation, eighteen (36.8%) had transanal excision and other procedures. RESULTS: Seventeen(34.7%) of 49 were villous adenomas containing invasive carcinoma. The rates of recurrence and complication of Mason's operation were 0% and 10% (2/20), Dixon's operation were both 18% (2/11), other procedures were 33.3% (6/18) and 16.7% (3/18). CONCLUSION: Mason's operation for most cases of villous adenomas at mid and low rectum can be a safe and effective method of treatment.

Adenoma, Villous↗
PubMed1999

Identification of a cytochrome b-type NAD(P)H oxidoreductase ubiquitously expressed in human cells.

Cytochrome b-type NAD(P)H oxidoreductases are involved in many physiological processes, including iron uptake in yeast, the respiratory burst, and perhaps oxygen sensing in mammals. We have identified a cytosolic cytochrome b-type NAD(P)H oxidoreductase in mammals, a flavohemoprotein (b5+b5R) containing cytochrome b5 (b5) and b5 reductase (b5R) domains. A genetic approach, using BLAST searches against DBEST for FAD-, NAD(P)H-binding sequences followed by reverse transcription-PCR, was used to clone the complete cDNA sequence of human b5+b5R from the hepatoma cell line Hep 3B. Compared with the classical single-domain b5 and b5R proteins localized on endoplasmic reticulum membrane, b5+b5R also has binding motifs for heme, FAD, and NAD(P)H prosthetic groups but no membrane anchor. The human b5+b5R transcript was expressed at similar levels in all tissues and cell lines that were tested. The two functional domains b5* and b5R* are linked by an approximately 100-aa-long hinge bearing no sequence homology to any known proteins. When human b5+b5R was expressed as c-myc adduct in COS-7 cells, confocal microscopy revealed a cytosolic localization at the perinuclear space. The recombinant b5+b5R protein can be reduced by NAD(P)H, generating spectrum typical of reduced cytochrome b with alpha, beta, and Soret peaks at 557, 527, and 425 nm, respectively. Human b5+b5R flavohemoprotein is a NAD(P)H oxidoreductase, demonstrated by superoxide production in the presence of air and excess NAD(P)H and by cytochrome c reduction in vitro. The properties of this protein make it a plausible candidate oxygen sensor.

Amino Acid Sequence↗
PubMed1999

Tyrosine replacement in P-selectin glycoprotein ligand-1 affects distinct kinetic and mechanical properties of bonds with P- and L-selectin.

Selectins are adhesion molecules that initiate tethering and rolling of leukocytes on the vessel wall. Rolling requires rapid formation and breakage of selectin-ligand bonds that must have mechanical strength to resist premature dissociation by the forces applied in shear flow. P- and L-selectin bind to the N-terminal region of P-selectin glycoprotein ligand-1 (PSGL-1), a mucin on leukocytes. To define determinants on PSGL-1 that contribute to the kinetic and mechanical properties of bonds with selectins, we compared rolling of transfected preB cells expressing P- or L-selectin on transfected cell monolayers expressing wild-type PSGL-1 or PSGL-1 constructs with substitutions in targeted N-terminal residues. Rolling through P- or L-selectin required a Thr or Ser at a specific position on PSGL-1, the attachment site for an essential O-glycan, but required only one of three nearby Tyr residues, which are sites for Tyr-SO(3) formation. The adhesive strengths and numbers of cells rolling through P- or L-selectin were similar on wild-type PSGL-1 and on each of the three PSGL-1 constructs containing only a single Tyr. However, the cells rolled more irregularly on the single-Tyr forms of PSGL-1. Analysis of the lifetimes of transient tethers on limiting densities of PSGL-1 revealed that L-selectin dissociated faster from single-Tyr than wild-type PSGL-1 at all shears examined. In sharp contrast, P-selectin dissociated faster from single-Tyr than wild-type PSGL-1 at higher shear but not at lower shear. Thus, tyrosine replacements in PSGL-1 affect distinct kinetic and mechanical properties of bonds with P- and L-selectin.

Amino Acid Sequence↗
PubMed1999

Studies of peptide binding to allyl amine and vinyl acetic acid-modified polymers using matrix-assisted laser desorption/ionization mass spectrometry.

Previous studies have shown that increases in surface-peptide binding affinity result in decreases in peptide matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) ion signals. The present work demonstrates that, with appropriate corrections for peptide ionization efficiency under MALDI conditions, relative surface-peptide binding affinities can be assayed using the MALDI MS methodology. Peptides with a range of pI values are allowed to interact with amine-modified and carboxylic acid-modified polymer surfaces (produced by pulsed radio-frequency plasma polymerization of allyl amine and vinyl acetic acid) in buffered solutions of neutral pH. Because of the net positive and negative charges associated with the peptides and surfaces in solution, both electrostatic and hydrophilic interactions play a role in the surface-peptide interaction. Consistent with expectations, the peptide MALDI ion signals for peptides with net negative charges in solution are smaller than those for peptides with net positive charges in solution when the peptides are allowed to interact with positively charged surfaces. A reversal of the relative peptide MALDI ion signal intensities is observed when the same peptides are allowed to interact with negatively charged surfaces. Cumulatively, the results demonstrate that even modest changes in surface-peptide interactions can be comparatively probed by MALDI mass spectrometry.

Amines↗
PubMed1999

Clinical effects and mechanism of chanlibao in accelerating second stage of labor.

To observe the clinical effects and the mechanism of Chanlibao (CLB, a preparation of Chinese herbal medicine) in accelerating second stage of labor, primiparae were divided into 3 groups at random. CLB or oxytocin (OTC) was given to the CLB group (n = 80) and the OTC group (n = 52) respectively. The third group served as controls (n = 29). The control group consisted of women experiencing natural labor and to whom no drug was given. The time of second stage of labor and prognosis of mother and newborn of different groups were observed and compared. And intrauterine pressure and fetal heart rate were monitored by means of electronic monitoring. Isolated uterine muscular tissue was used to observe the reactivity to CLB. The results showed that the time of second stage of labor and postpartum hemorrhage in the CLB group were less than those in the control group and the average intrauterine pressure in the former was higher than that in latter, so was the contraction strength of isolated uterine muscle, but with no difference as compared with the OTC group. No side effect of CLB was found. It is concluded that CLB could obviously strengthen uterine contraction and accelerate second stage of labor. Moreover, it is inexpensive, convenient and free of side effect. It can be used as a new, safe and effective alternative for improving prognosis of mother and newborn, especially those not indicated for oxytocin or profuse infusion.

Adult↗
PubMed1999

Genetic susceptibility to pre-eclampsia and chromosome 7q36.

Pre-eclampsia is the most common serious medical disorder of human pregnancy. The human endothelial cell nitric oxide synthase (eNOS) gene is a candidate for pre-eclampsia/eclampsia (PE/E) susceptibility. A linkage study was performed on Australian PE/E families using 25 microsatellite markers from chromosome 7, one of which (eNOS-CA) resides within the eNOS gene. No significant linkage was found for the eNOS-CA marker using either parametric or non-parametric analysis. However, D7S 1805 from the eNOS gene region on 7q36, gave a suggestion of linkage using parametric analysis (maximum LOD score =2.143 at theta=0.14) and non-parametric APM analysis (T1/sqrt(p)=3.53; P=0.002). Further, an association study was performed on unrelated PE/E cases and controls from both Chinese and Australian populations to test for a relationship between the eNOS gene and PE/E. No association was found between the eNOS-CA marker and PE/E in either population. However, there was a significant difference in the allelic distribution of eNOS-CA between the two ethnic groups. The linkage results support the possibility that a susceptibility locus for pre-eclampsia resides in the 7q36 region, however, there is no definitive evidence to support the notion that the eNOS gene itself is responsible for susceptibility to pre-eclampsia.

Asian People↗
PubMed1999

Loss of retinoic acid receptor-beta expression is an early event during esophageal carcinogenesis.

We recently observed that growth inhibition of esophageal cancer cells by retinoic acid (RA) was associated with both constitutive expression and RA-induced up-regulation of RA receptor beta (RAR-beta). Cell lines that did not express RAR-beta were also resistant to RA. To explore the expression of RAR-beta mRNA in vivo, we analyzed esophageal tissue specimens from 16 normal mucosae, 30 dysplastic lesions, and 157 esophageal tumors by in situ hybridization. RAR-beta was detected in 88% (14/16) of normal esophageal tissues and in 96% (96/100) of distant normal esophageal mucosa from cancer specimens. In contrast, RAR-beta was expressed in only 57% (17/30) of dysplastic lesions and in 54% (84/157) of carcinomas. Among esophageal carcinomas RAR-beta mRNA was expressed in 62% (26/42) of well-differentiated, 54% (27/50) of moderately differentiated, and only 29% (4/14) of poorly differentiated SCCs. Our data suggest that the loss of RAR-beta expression is an early event associated with esophageal carcinogenesis and the status of squamous differentiation.

Aged↗
PubMed1999

Phase behavior of the monoerucin/water system.

Monoerucin is a monoacylglycerol incorporating a cis monounsaturated fatty acid, 22 carbon atoms long, with the double bond at carbon number 13. The original temperature-composition phase diagram for the monoerucin/water system, constructed on the basis of 'consistency' and light microscopy, includes unexpectedly only the lamellar and fluid isotropic phases [Lutton, E.S., 1965. J. Am. Oil Chem. Soc. 42:1068-1070]. In separate studies using X-ray diffraction, the cubic phase [Larsson et al., 1978. J. Sci. Food Agric. 29:909-914] and the inverted hexagonal (HII) phase [Caffrey, M., 1989. Biophys. J. 95:11-21] were shown to be the dominant phases. We have resorted to the traditional isoplethal diffraction method for constructing the equilibrium phase diagram of monoerucin in water with a view to resolving the controversy regarding the thermotropic and lyotropic properties of the system. The study confirms the presence of the pure HII phase that extends from ca. 10 to 22% (w/w) water and from ca. 35 to 125 degrees C, and its coexistence with excess water above ca. 24% (w/w) water in the same temperature range. The low temperature region of the diagram is dominated by the lamellar crystal (Lc) phase, with the existence of the lamellar liquid crystal (L alpha) and cubic-Ia3d phases at intermediate temperatures and hydration levels. Differential scanning calorimetry and polarizing light microscopy were used to confirm the reported equilibrium phase behavior. Full structure characterization of the system and how phase microstructure depends on sample hydration and temperature are reported.

Calorimetry, Differential Scanning↗
PubMed1999

Calcium-induced activation of a mutant G-protein-coupled receptor causes in vitro transformation of NIH/3T3 cells.

The calcium-sensing receptor (CaR) is a G-protein-coupled receptor that is widely expressed, has tissue-specific functions, and regulates cell growth. Activating mutations of this receptor cause autosomal dominant hypocalcemia, a syndrome characterized by hypocalcemia and hypercalciuria. The identification of a family with an activating mutation of the CaR (Thr151Met) in which hypocalcemia cosegregates with several unusual neoplasms led us to examine the transforming effects of this mutant receptor. Transfection of NIH/3T3 cells with the mutant but not the normal receptor supported colony formation in soft agar at subphysiologic calcium concentrations. The mutant CaR causes a calcium-dependent activation of the extracellular signal-regulated protein kinase (ERK) 1/2 and Jun-N-terminal kinase/stress-activated (JNK/ SAPK) pathways, but not P38 MAP kinase. These findings contribute to a growing body of information suggesting that this receptor plays a role in the regulation of cellular proliferation, and that aberrant activation of the mutant receptor in this family may play a role in the unusual neoplastic manifestations.

3T3 Cells↗
PubMed1999

[Analysis of complications and deaths in aged patients with obstructive jaundice].

The reasons of complications and deaths in 98 aged patients with obstructive jaundice were analysed in the paper. Among them, 52 cases were diagnosed as benign obstruction, 46 cases as malignant obstruction; 92 patients were treated by surgical management(15 died), 6 patients were treated without operation(4 died). The results showed that effective management on time and intensive perioperative care are important to minimize the mortality rate. Malignant obstructive jaundice was more harmful to the patients' renal function no the mortality rate would be increased. The operations, internal drainage and pressure reduction of biliary duct, were performed on time, thus the survival rate was improve.

Aged↗
PubMed1998

Homodimerization restores biological activity to an inactive erythropoietin mutant.

Erythropoietin (Epo) is believed to transduce a signal by bringing two Epo receptors into close proximity, enabling cross-phosphorylation. We compared monomeric Epos with homodimers in which two Epo monomers are linked by polyglycine. Monomeric Epo mutant R103A is unable to support Epo-dependent cell growth or trigger Janus kinase 2 and STAT5 activation, even at concentrations greater than 7,000 times that sufficient for wild-type Epo activity. In contrast, R103A homodimer induces proliferation and transduces signal at concentrations similar to that of wild-type Epo monomer and homodimer. These experiments show that two discrete domains on Epo are required for receptor binding and activation. Our results also suggest that the EpoR can be dimerized by different forms and sizes of molecules, as long as two recognition motifs are provided in the same molecule. Design of other dimeric molecules may enhance our understanding of cytokine specificity and signal transduction.

Animals↗
PubMed1998

A simple mechanical mixer for small viscous lipid-containing samples.

The construction and performance characteristics of a simple device for rapid and convenient hydration and mixing of small volumes (10-500 microliters) of viscous hydrated lipid samples for use in X-ray diffraction/scattering and other applications are described. The mixer has been used successfully over the past several years in studies of the equilibrium properties of lipid mesophases and of the kinetics and mechanism of phase transitions. It is a low dead-volume (3.6-11.2 microliters) device that was built to facilitate maximal transfer of homogeneously hydrated lipid from the mixer into 1 mm diameter X-ray capillaries with minimal loss of water during transfer and sample manipulation. The device consists of inexpensive, commercially available parts, the most important of which are two microsyringes joined by a small-bore coupling needle. Also described in this report is a technique for determining the water content of the small volume, hydrated samples prepared with the mixer and an accessory for conveniently heating and/or degassing samples during mixing. Inadvertent sample heating that occurs during mixing is described.

Lipids↗
PubMed1998

Dimerization by translation initiation factor 2 kinase GCN2 is mediated by interactions in the C-terminal ribosome-binding region and the protein kinase domain.

The protein kinase GCN2 stimulates translation of the transcriptional activator GCN4 in yeast cells starved for amino acids by phosphorylating translation initiation factor 2. Several regulatory domains, including a pseudokinase domain, a histidyl-tRNA synthetase (HisRS)-related region, and a C-terminal (C-term) segment required for ribosome association, have been identified in GCN2. We used the yeast two-hybrid assay, coimmunoprecipitation analysis, and in vitro binding assays to investigate physical interactions between the different functional domains of GCN2. A segment containing about two thirds of the protein kinase (PK) catalytic domain and another containing the C-term region of GCN2 interacted with themselves in the two-hybrid assay, and both the PK and the C-term domains could be coimmunoprecipitated with wild-type GCN2 from yeast cell extracts. In addition, in vitro-translated PK and C-term segments showed specific binding in vitro to recombinant glutathione S-transferase (GST)-PK and GST-C-term fusion proteins, respectively. Wild-type GCN2 could be coimmunoprecipitated with a full-length LexA-GCN2 fusion protein from cell extracts, providing direct evidence for dimerization by full-length GCN2 molecules. Deleting the C-term or PK segments abolished or reduced, respectively, the yield of GCN2-LexA-GCN2 complexes. These results provide in vivo and in vitro evidence that GCN2 dimerizes through self-interactions involving the C-term and PK domains. The PK domain showed pairwise in vitro binding interactions with the pseudokinase, HisRS, and C-term domains; additionally, the HisRS domain interacted with the C-term region. We propose that physical interactions between the PK domain and its flanking regulatory regions and dimerization through the PK and C-term domains both play important roles in restricting GCN2 kinase activity to amino acid-starved cells.

Binding Sites↗