Biomedical subjects

H Qian

Publications and source records attributed to H Qian.

At least 91 records · Page 5Linked to original sources

PubMed1999

[In vitro study of 6B11GM to induce cellular immunity in patients with ovarian carcinoma].

OBJECTIVE: In order to explore the possibility of ovarian carcinoma anti-idiotypic single chain antibody (6B11scFV) and human granueocyte-macrophage colony stimulating factor (hGM-CSF) fusion protein 6B11GM as tumor vaccine. METHODS: Mononuclear cells, T cells and monocyte used as antigen presenting cell (APC) were separated from peripheral blood, and tumor cells were obtained from ascitic fluid in the same patients. In vitro T cell proliferation and autologous tumor cell cytotoxicity assay were applied. RESULTS: 6B11GM could induce T cell proliferation in vitro which was antigen specific. Cytotoxicity of mononuclear cells to autologous tumor cells increased after primed with 6B11GM. CONCLUSION: 6B11GM could induce efficient cellular immunity in patients with ovarian carcinoma, hopefully may be used for ovarian carcinoma vaccine.

Adenocarcinoma↗

PubMed1999

[High-level expression of 6B11 ovarian carcinoma anti-idiotypic antibody scFv genes in E. Coli].

OBJECTIVE: To express high-level 6B11 ovarian carcinoma anti-idiotypic antibody single chain Fv (scFv) genes in E. Coli. METHODS: Using PCR cloning technique, We cloned 6B11scFv genes into bacterial expression vector pKPL-3a. Recombinant plasmid vector pL-6B11scFv was transformed into E. Coli pop2136 with temperature control to produce proteins. Renaturated proteins were purified on DEAE-Sepharose Fast Flow ion exchange column with salt gradient elution. Immunoactivity was determined with ELISA and inhibition ELISA tests respectively. RESULTS: 6B11scFv genes were expressed as inclusion bodies in the cytoplasm. The purity of 6B11scFv turned out by SDS-PAGE was more than 95%. The expressed proteins after purification specifically reacted with anti-ovarian carcinoma monoclonal antibody COC166-9 and efficiently inhibited the reaction between primary ovarian carcinoma antigen OC166-9 and COC166-9. CONCLUSION: We successfully expressed high-level 6B11scFv genes in E. Coli. Expressed proteins showed pretty good immunoactivity.

Antibodies, Anti-Idiotypic↗

PubMed1999

[The application of Apo-1/Fas to evaluate apoptosis of myocardial cells in patients with congestive heart failure].

OBJECTIVE: To study the changes of serum level of Apo-1/Fas in patients with congestive heart failure (CHF) and evaluate apoptosis of failing myocardial cells. METHODS: Strepavidin-Biotin ELISA was used to determine serum level of Apo-1/Fas, interleukin-6 (IL-6) and tumor necrosis factor (TNF alpha) in 60 patients with CHF. Cardiac ejection fraction (EF) of the patients were measured by acusson 128XP/10 echocardiograph. RESULTS: Serum levels of Apo-1/Fas and TNF alpha in class III and IV patients with CHF were significantly higher than those in class I and II (P < 0.01). Serum levels of IL-6 in all the patients were obviously higher than those in controls (P < 0.05 and 0.01) and the levels in class III and IV patients were significantly higher than those in class I and II (P < 0.05). Serum levels of Apo-1/Fas in patients with EF < 55 percent were higher than in those with EF > 55 percent (P < 0.05). CONCLUSION: Serum level of Apo-1/Fas in patients with CHF reflects a state of apoptosis in failing myocardial cells. IL-6 and TNF alpha have important effects on immune regulation of myocardial cell apoptosis.

Adult↗

PubMed1999

[Evaluation of immunochromatographic test in the diagnosis of Plasmodium falciparum and Plasmodium vivax].

AIM: To evaluate the effectiveness of immunochromatographic test(ICT) in detecting Plasmodium falciparum and Plasmodium vivax in malaria endemic areas. METHODS: ICT was used to detect P. falciparum and P. vivax among patients with fever in the outpatient clinics by comparason with thick blood smear method. RESULTS: The sensitivity of ICT to detect P. falciparum and P. vivax was 96.7% and 90.4%, respectively. The specificity of ICT was 98.6%, and the coincidence rate was 94.7%. There is no cross reaction between P. falciparum and P. vivax. CONCLUSION: ICT could detect P. falciparum and P. vivax simutaneously, being more rapid and simple than blood smear method.

Animals↗

PubMed1999

[The analysis of auditory brainstem response during resection of brainstem neoplasm].

OBJECTIVE: To evaluate changes of auditory brainstem response (ABR) and its role in monitoring auditory functions during the brainstem surgery. METHODS: The data of 400 ABRs from 5 operations for removal of astrocytic glioma, cavernomas or dermoid from the brainstem were analyzed. The changes in latencies, amplitudes and wavefroms were dynamically observed and statistically analyzed with t test and Factor analysis. RESULTS: Surgical manipulations, such as stretching, separation and extrusion, induced the prolongation of ABR peaks and interpeak latencies of waves I, III, V. The amplitudes of waves decreased. Three out of 5 cases presented reversible changes in latencies and wave forms. The dynamical analysis showed: The maximal variable range of latency(LMVD) was more than 11.30%, the maximal reversible degree of latency(LMRD) was more than 53.85%, the time of convalescent half-value latency(LCHT) was around 8-40 min, AMVD was more than 40%, the AMRD was more than 200%, and the ACHT was around 5-40 min. In 2 out of the 5 patients the postoperative ABR latencies kept prolonged, some postoperative waves were malformed and difficult to be identified, One case died, another lost consciousness, their LMRDs were less than 33.33%. These findings suggested that surgical intervention had significant effects on the ABR latency (P < 0.01). CONCLUSION: ABR offers a promise for sensitive detection of the brainstem function. Its latency, amplitude and waveform show us dynamic changes of the brainstem status and can be used as an index during the operation on the brainstem and its adjacent region.

Adult↗

PubMed1999

Deletions and point mutations of p16,p15 gene in primary tumors and tumor cell lines.

Aberrations of chromosome 9 p21-22 are involved in the genesis of many forms of cancer. The gene p16 and p15 have been assigned to this region. Both p16 and p15 are an inhibitor of cyclin D-cdk4,cyclin D-cdk6 complex and have been implicated in a wide variety of cancer types, including the germline of patients with familial melanoma. In order to investigate and compare the status of p16,p15 gene in primary tumors and cell lines, we examined 357 primary tumors and 29 cell lines derived from diverse tumor types. In addition to analysis of these primary tumors and cell lines, blood specimens from 91 patients either with sporadic multiple cancers or from cancer-prone families were also analyzed. The data showed the following: 1) Homozygous deletions of p16,p15 were comparatively rare and far less common than previously reported, although hemizygous deletions were observed in a significant fraction of many tumor types; 2) the incidence of p16,p15 deletions (either homozygous deletions or heterozygous deletions) varied significantly among different tumor types; 3) most deletions involved in both p16 and p15 genes; 4) sequence variations in the coding sequence of p16,p15 were comparatively rare among these tumor types, though mutations and polymorphisms were identified; 5) some tumors which showed LOH at 9p, containing p16 and p15 gene, did not show deletions or point mutations in the p16,p15 gene. 6) In a subset of retinoblastoma and osteosarcoma where no Rb gene mutations were present a significant fraction was found to contain p16,p15 gene deletions.

Bone Neoplasms↗

PubMed1998

Down-regulation of CCAAT/enhancer binding proteins alpha, beta and delta in adipose tissue by intracerebroventricular leptin in rats.

In our previous report, intracerebroventricular (i.c.v.) administration of leptin caused fat depletion by an induced adipocyte apoptosis in addition to influencing lipid metabolism. To uncover the biochemical mechanisms that mediate this response, the present study was designed to determine whether CCAAT/enhancer binding proteins (C/EBP)alpha, -beta and -delta play a role in the leptin-induced fat depletion. Expressions of C/EBPalpha, -beta and -delta in epididymal fat tissues were examined by Western immunoblot and in situ immunocytochemical analysis after 5 days of i.c.v. treatment. Young and old rats (3 and 8 months old) were treated with or without 5 micrograms/day leptin. The expression of C/EBPalpha, -beta and -delta was decreased by i.c.v. leptin treatment in young rats as compared with controls (P<0.05). However, leptin did not influence the expression of C/EBPalpha, -beta and -delta in adipose tissues of 8-month-old rats. The basal level of expression of C/EBPbeta was greater in 8-month-old rats than in 3-month-old rats, (P<0.05) whereas the basal expression of C/EBPalpha and -delta was not different between age groups. These results were confirmed by in situ immunocytochemical analysis. The present study suggests that leptin-induced down-regulation of C/EBPalpha, -beta and -delta might influence adipocyte differentiation and growth in a number of ways.

Adipose Tissue↗

PubMed1998

Simultaneous determination of fat-soluble vitamins A, D and E and pro-vitamin D2 in animal feeds by one-step extraction and high-performance liquid chromatography analysis.

Traditionally, alkaline saponification for the extraction of vitamins and step-wise HPLC analyses have been widely used for analysis of fat-soluble vitamins in animal feeds. The objective of present study was to develop an analytical method using one-step extraction and simultaneous determination of the vitamins A, D and E and pro-vitamin D2 in animals feeds b HPLC. Various analytical conditions were tested which included sample particle size extraction solvents, the ratio of solvent to sample, extraction approach, extraction time, N2 protection, prepurification with Sep-Pak cartridge and detection wavelength. The accuracy of the developed method has been proven by comparison with the AOAC method. The reproducibility of the developed method has been substantiated by repeated recovery experiments. The detection limit for the four vitamins was 10 ng/g of feed sample. One of the important properties of the present method is rapidity and ease of use.

Animal Feed↗

PubMed1998

Molecular and pharmacological properties of GABA-rho subunits from white perch retina.

Five gamma-aminobutyric acid (GABA)-rho subunits were cloned from a white perch retinal cDNA library and expressed in Xenopus oocytes. The deduced amino acid sequences indicated that all are highly homologous to the GABA-rho subunits cloned from mammalian retinas; two clones (perch-rho 1A and perch-rho 1B) were in the rho 1 family, two (perch-rho 2A and perch-rho 2B) were in the rho 2 family, and one clone has been tentatively identified as a perch-rho 3 subunit. When expressed in Xenopus oocytes, all but one of the subunits (rho 3) formed functional homooligomeric receptors. However, the receptors expressed by each of the GABA-rho subunits displayed unique response properties that distinguished one from the other. For example, receptors formed by perch-rho 1B subunits were more sensitive to GABA than the receptors formed by other GABA-rho subunits, the dose-response curves for the various receptors revealed different Hill coefficients, and there were differences in the kinetics of the GABA-induced currents. In addition, the GABA-mediated current-voltage curve for rho 2 receptors was approximately linear, whereas the responses from rho 1 receptors showed outward rectification. A further division in the properties of the GABA-rho subunits was revealed in their responses to imidazole-4-acetic acid (I4AA); the drug behaved as an antagonist on A-type rho receptors and a partial agonist on the B-type rho receptors. These results suggest that there is a large diversity of GABAC receptors in the vertebrate retina, probably formed by homooligomeric and heterooligomeric combinations of GABA rho subunits, that exhibit different functional properties.

Amino Acid Sequence↗

PubMed1998

In vivo gene transfer of nitric oxide synthase enhances vasomotor function in carotid arteries from normal and cholesterol-Fed rabbits.

BACKGROUND: The vascular endothelium is anatomically intact but functionally abnormal in preatherosclerotic states, and an early deficit in the bioavailability of nitric oxide (NO) or related molecules has been described in both humans and animal models. We hypothesized that the targeted gene transfer of NO synthase (NOS) isoforms might ameliorate or reverse the deficit. METHODS AND RESULTS: We constructed a recombinant adenovirus, Ad.nNOS, that expresses the neuronal isoform of NOS (nNOS) and used it for in vivo endovascular gene transfer to carotid arteries (CA) from normal and cholesterol-fed rabbits. Vessels were harvested 3 days after gene transfer. In CA from normal rabbits, Ad.nNOS generated high levels of functional nNOS protein predominantly in endothelial cells and increased vascular NOS activity by 3.4-fold relative to sham-infected control CA. Ad.nNOS gene transfer also significantly enhanced endothelium-dependent vascular relaxation to acetylcholine; at 3 micromol/L acetylcholine, Ad.nNOS-treated arteries showed an 86+/-4% reduction in precontracted tension, whereas control CA showed a 47+/-6% reduction in tension. Contraction in response to phenylephrine and relaxation in response to nitroprusside were unaffected in both control and Ad.nNOS-treated CA. To determine the effect of Ad.nNOS in atherosclerotic arteries, 10 male New Zealand White rabbits maintained on a 1% cholesterol diet for 10 to 12 weeks underwent gene transfer according to the same protocol used in normal rabbits. Ad.nNOS-treated arteries showed a 2-fold increase in NADPH-diaphorase staining intensity relative to sham-infected and Ad. betaGal-treated arteries. The CA from cholesterol-fed rabbits showed impaired acetylcholine-induced relaxation, but this abnormality was almost entirely corrected by Ad.nNOS gene transfer. CONCLUSIONS: In vivo adenovirus-mediated endovascular delivery of nNOS markedly enhances vascular NOS activity and can favorably influence endothelial physiology in the intact and atherosclerotic vessel wall.

Animals↗

PubMed1998

Hysteresis in force probe measurements: a dynamical systems perspective.

Macromolecular binding forces between single protein-ligand pairs have been directly measured with the Atomic Force Microscope (AFM) in several recent experiments. In a typical measurement, the AFM probe, or cantilever, is attached to the ligand and exerts a disruptive force on the bond between the macromolecular pair while the receptor is held fixed; the probe is then moved away from the substrate until the bond is broken. When the bond actually breaks, the tip is observed to slip; in fact, the ligand is jumping to a new equilibrium point determined purely by the cantilever, as if the receptor had been instantaneously moved to infinity. This "jumping-off" or "minimum rupture force" is determined by measuring cantilever deflection. In a similar manner, the two molecules can be brought together and the "jumping-on" force can be determined. These two measurements will result in different estimates of the binding force due to hysteresis. This hysteresis is caused by a cusp catastrophe in the space defined by probe position and cantilever stiffness. The phenomena of "jumping-off" in macromolecular rupture experiments and "jumping-on" when molecules are brought together occur when the system passes through a saddle-node bifurcation as the probe position is varied. Probe approach and withdrawal result in different post-bifurcation equilibria, different energy dissipation, and different force measurements.

Animals↗

PubMed1998

NMR solution structure of the oxidized form of MerP, a mercuric ion binding protein involved in bacterial mercuric ion resistance.

Mercuric ions are toxic to living organisms because of their strong affinity for cysteine residues in proteins. Some bacteria have developed a resistance mechanism whereby Hg2+ is transported into the cytoplasm and reduced to Hg0. One of the proteins involved in the transport of mercuric ion is the periplasmic binding protein MerP, which can exist both as oxidized (disulfide) and as reduced (dithiol) forms. Only the reduced form with Cys-17 and Cys-14 residues as free thiols is a potent receptor for mercuric ion. In this work the solution structure of the oxidized form of MerP has been determined by multidimensional NMR spectroscopy and compared to the NMR structures of the previously published structures of the reduced and mercury-bound forms of MerP. The mercury-bound and oxidized forms have similar tertiary structures, whereas in the reduced form there is a large rearrangement of the mercuric ion binding loop and the nearby loop comprising residues 38-41. The structural arrangement of the latter loop seems to be important for the stabilization of the surface location of the cysteine-containing loop. In the reduced form at low pH the cysteine-containing loop adopts a conformation similar to what is observed in the oxidized and mercury-bound forms. The oxidized form also differs with respect to the other two forms in the relative positions of some of the alpha-helices and beta-strands. Structural differences between the oxidized and reduced forms may help explain why the reduced form is stable in the periplasm, which is considered to be an oxidizing environment.

Bacterial Proteins↗

PubMed1998

Leptin regulation of peroxisome proliferator-activated receptor-gamma, tumor necrosis factor, and uncoupling protein-2 expression in adipose tissues.

It has previously been reported that intracerebroventricular (i.c.v.) administration of leptin induced adipose tissue apoptosis in addition to influencing lipid metabolism. The objective of the present study was to determine if the expressions of peroxisome proliferator-activated receptor-gamma (PPAR gamma), uncoupling protein-2 (UCP2), and tumor necrosis factor (TNF alpha) were influenced by in vivo leptin treatment. Expression of PPAR gamma, UCP2, and TNF alpha in epididymal fat tissue was examined by Western immunoblot and in situ immunocytochemical analysis after 5 days of i.c.v. leptin treatment. Young and old rats (3 and 8 months old) were treated with or without 5 micrograms/d leptin. Leptin treatment increased PPAR gamma expression by 70-80% (P < 0.01) in both age groups. Leptin treatment decreased the expression of UCP2 (P < 0.01) in young rats, whereas it increased UCP2 expression (P < 0.01) in old rats. Leptin treatment also decreased TNF alpha expression by 40% (P < 0.01) in young rats but did not influence its expression in old rats. The basal level of expression of PPAR gamma was greater in 3-month-old rats than in 8-month-old rats. The basal level of UCP2 and TNF alpha expression was not different between the two age groups. These immunoblotting data were further confirmed by in situ immunocytochemical analysis. The present study suggests that expression of PPAR gamma may be directly involved in the leptin-induced adipocyte apoptosis signal pathway, whereas UCP2 and TNF alpha may play roles in the leptin-induced lipolysis process.

Adipose Tissue↗

PubMed1998

Antibody-mediated targeting of CD45 isoforms: a novel immunotherapeutic strategy.

CD45 is a family of transmembrane protein tyrosine phosphatases exclusively expressed by hematopoietic cells and critically involved in the regulation of T cell activation signals. We now demonstrate that three 100-microg doses of anti-CD45RB mAb MB23G2 can induce long-term engraftment of islets into major histcompatibility complex-disparate chemically diabetic mice. Long-term graft survivors (>120 days) were tolerant to new islet allografts from the original donor strain. MB23G2 induced a temporary decrease in number circulating leukocytes but had no effect on leukocyte number in other lymphoid compartments. Histologic examination of allografts from treated and untreated recipients revealed a similar peri-islet infiltration on day 6. Eleven days after transplant, the peri-islet infiltrate in treated animals persisted, but in marked contrast to untreated control animals, there was no insulitis and islet integrity was preserved. The peri-islet infiltrate from treated animals showed a mild increase in CD4 cells, a decrease in CD8 cells, and decreased intensity of CD45RB expression. Treatment of naive animals with anti-CD45RB (MB23G2) resulted in a shift in CD45 isoform expression on T cells with a loss of higher molecular weight isoforms and increased expression of lower molecular weight (CD45R0) isoform. This shift in CD45 isoform expression from CD45RBHi to CD45RBLo was associated with an increase in the intragraft expression of transcripts for interleukin (IL) 4 and IL-10, consistent with the expected activity of this distinct immunoregulatory T cell subset. Antibody-mediated targeting of CD45 may induce tolerance through novel mechanisms and have direct applicability to clinical transplantation in humans.

Animals↗

PubMed1998

Sequential assignment of 1H, 15N, 13C resonances and secondary structure of human calmodulin-like protein determined by NMR spectroscopy.

Human calmodulin-like protein (CLP) is closely related to vertebrate calmodulin, yet its unique cell specific expression pattern, overlapping but divergent biochemical properties, and specific target proteins suggest that it is not an isoform of calmodulin. To gain insight into the structural differences that may underlie the difference target specificities and biochemical properties of CLP when compared to calmodulin, we determined the sequential backbone assignment and associated secondary structure of 144 out of the 148 residues of Ca2+-CLP by using multinuclear multidimensional NMR spectroscopy. Despite a very high overall degree of structural similarity between CLP and calmodulin, a number of significant differences were found mainly in the length of alpha-helices and in the central nonhelical flexible region. Interestingly, the regions of greatest primary sequence divergence between CLP and calmodulin in helices III and VIII displayed only minor secondary structure differences. The data suggest that the distinct differences in target specificity and biochemical properties of CLP and calmodulin result from the sum of several minor structural and side-chain changes spread over multiple domains in these proteins.

Amino Acid Sequence↗

PubMed1998

Remarks on discrete and continuous large-scale models of DNA dynamics.

We present a comparison of the continuous versus discrete models of large-scale DNA conformation, focusing on issues of relevance to molecular dynamics. Starting from conventional expressions for elastic potential energy, we derive elastic dynamic equations in terms of Cartesian coordinates of the helical axis curve, together with a twist function representing the helical or excess twist. It is noted that the conventional potential energies for the two models are not consistent. In addition, we derive expressions for random Brownian forcing for the nonlinear elastic dynamics and discuss the nature of such forces in a continuous system.

Biophysics↗

PubMed1998

Blood flows and metabolic components of the cardiome.

This is a plan for the first stage of The Cardiome Project. The cardiome is the representation, in quantitative, testable form, of the functioning of the normal heart and its responses to intervention. The goal is to integrate the efforts of many years into a comprehensive understandable scheme. Past efforts have spanned the fields of transport within blood vessels, the distributions of regional coronary blood flows, permeation processes through capillary and cell walls, mediated cell membrane transport, extra- and intracellular diffusion, cardiac electrophysiology, the uptake and metabolism of the prime substrates (fatty acid and glucose), the metabolism of the purine nucleosides and nucleotides (mainly adenosine and ATP), the regulation of the ionic currents and of excitation-contraction coupling and finally the regulation of contraction. The central theme is to define the coronary flows and metabolic components of a computer model that will become a part of a three-dimensional heart with appropriate fibre shortening and volume ejection. The components are: (a) coronary flow distributions with appropriate heterogeneity, (b) metabolism of the substrates for energy production, (c) ATP, PCr and energy metabolism and (d) calcium metabolism as it relates to excitation-contraction coupling. The modeling should provide: (1) appropriate responses to regional ischemia induced by constriction of a coronary artery, including tissue contractility loss and aneurysmal dilation of the ischemic region; (2) physiological responses to rate changes such as treppe and changes in metabolic demand and (3) changes in local metabolic needs secondary to changes in the site of pacing stimulation and shortening inactivation or stretch activation of contraction.

Adenosine↗

PubMed1998

Superoxide production after spinal injury detected by microperfusion of cytochrome c.

Highly reactive oxygen-containing species may form upon CNS injury and cause oxidative damage to important cellular components, thereby destroying cells. To test this hypothesis, free radical formation following such insults should be characterized first. In this study, we measured the time course of superoxide production following impact injury to the rat spinal cord using a novel microcannula perfusion technique developed by us. Cytochrome c (50 microM in artificial cerebrospinal fluid) was perfused into the rat spinal cord through the cannula inserted laterally into the gray matter of the cord, and reduced cytochrome c was measured from perfusates spectrophotometrically. We found that the levels of superoxide in the extracellular space increased to approximately twice the basal level and remained elevated for over 10 h. Superoxide dismutase (60 U/ml) significantly reduced the elevation of superoxide levels (p = .016) and ferric chloride (0.1 mM)/EDTA (0.25 mM) infused together with cytochrome c completely removed the superoxide measured, validating the measurement of superoxide. The relatively long-lasting formation of superoxide reported herein suggests that removal of superoxide may be a realistic treatment strategy for reducing injury caused by free radicals.

Animals↗