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Biomedical subjects

Z Q Li

Publications and source records attributed to Z Q Li.

At least 19 recordsLinked to original sources
PubMed2006

Earlier flowering induced by over-expression of CO gene does not accompany increase of artemisinin biosynthesis in Artemisia annua.

The early flowering gene CONSTANS (CO) from Arabidopsis thaliana was transferred into Artemisia annua using the Agrobacterium tumefaciens-mediated transformation system. The plant expression vector pBI CO was constructed by inserting the CO gene into the binary vector pBI121 under the control of CaMV 35S promoter. Analyses of PCR, PCR Southern blot, and Southern blot revealed that the transgenic plants contained the foreign CO gene. The results of RT-PCT and RT-PCR Southern blot suggested that the foreign CO gene had expressed at the transcriptional level. Although the flowering time of the CO transgenic plant was about 2 weeks earlier than that of the non-transgenic plant under short-day conditions, no significant difference in artemisinin content was found between the flowering transgenic plant and the non-flowering non-transgenic plant. These results show that the usually observed increase of artemisinin content before plant flowering under natural conditions is not a direct consequence of flowering itself, perhaps there is even no direct linkage between flowering and artemisinin biosynthesis.

Agrobacterium tumefaciens↗
PubMed2006

Infrared imaging of the nanometer-thick accumulation layer in organic field-effect transistors.

We report on infrared (IR) spectromicroscopy of the electronic excitations in nanometer-thick accumulation layers in field-effect transistor (FET) devices based on poly(3-hexylthiophene). IR data allows us to explore the charge injection landscape and uncovers the critical role of the gate insulator in defining relevant length scales. This work demonstrates the unique potential of IR spectroscopy for the investigation of physical phenomena at the nanoscale occurring at the semiconductor-insulator interface in FET devices.

Chemical Phenomena↗
PubMed2005

Humoral and cellular immune responses to Fasciola gigantica experimental infection in buffaloes.

Humoral and cellular immune responses to Fasciola gigantica experimental infection in buffaloes were studied. The results showed that 33.4+/-9.1% of the infection dose was recovered as adult flukes from infected animals at necropsy. Significant differences of weight gain between infected and non-infected buffaloes was observed at 4 MPI (months post-infection). Anti F. gigantica excretory-secretory products (FgESP)-IgG levels increased significantly from 3 WPI (weeks post-infection) and displayed a peak at 13 WPI. Western blot indicated that in FgESP six major bands of 11.5, 19.0, 23.4, 29.8, 47.5 and 53.2kDa were recognized by F. gigantica-infected buffaloes sera after 0 WPI. Eosinophil numbers increased significantly from 3 WPI in F. gigantica-infected buffaloes and displayed a peak at 8 WPI. Peripheral blood mononuclear cells (PBMC) proliferation induced by FgESP increased from 2 WPI with a peak at 5 WPI. IFNgamma secretion by FgESP-stimulated PBMC appeared early from 1 WPI with three peaks at 2, 5 and 8 WPI, respectively. IL-10 production was observed from 2 WPI with two peaks at 4 and 9 WPI, respectively. Our results suggested that buffaloes were highly susceptible to F. gigantica infection, and this susceptibility could be associated with the late and weak cellular immune response in the early phase of infection and the Th0-like response throughout the infection.

Animals↗
PubMed2005

Local anesthesia for functional endoscopic sinus surgery employing small volumes of epinephrine-containing solutions of lidocaine produces profound hypotension.

BACKGROUND: Local anesthetic containing epinephrine is commonly used in many operations for the main purpose of hemostasis. A randomized, controlled, prospective clinical trial was designed to find out hemodynamic changes after local infiltration of different concentrations and/or different dosages of epinephrine during functional endoscopic sinus surgery (FESS) under general anesthesia. METHODS: One hundred and eight adult patients undergoing elective FESS under general anesthesia were randomly allocated into four groups. Group I received 2% lidocaine 2 ml with epinephrine (5 microg/ml); group II received 1% lidocaine 4 ml with epinephrine (2.5 microg/ml); group III received 1% lidocaine 4 ml with epinephrine (5 microg/ml); and group IV received 1% lidocaine 4 ml for local infiltration. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were monitored continuously in the radial artery and recorded in 6 min: before infiltration (baseline), 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, and 6 min after local infiltration. The lowest blood pressure (BP) in this period was also recorded. RESULTS: Significant hemodynamic changes, particularly a decrease in BP (P < 0.001) with a slight increase in HR (P < 0.001) at approximately 1.5 min and an increase in SBP at approximately 3 min (P < 0.01) after local infiltration, were observed in group I, group II and group III compared with the baseline, but not in group IV. No significant hemodynamic differences were observed between group I, group II and group III at the same time points (P > 0.05). CONCLUSION: Local infiltration of low-dose epinephrine causes temporary significant hemodynamic changes particularly a marked decrease in BP during FESS under general anesthesia.

Adolescent↗
PubMed2002

Oncospheres of Taenia solium develop into cysticerci in normal mice.

In vitro-hatched oncospheres of Taenia solium, prepared by the sodium hypochlorite method and adjusted to approximately 5 x 10(2)/2ml phosphate buffer saline, were injected intramuscularly or intravenously into normal Balb/c mice. When these mice were sacrificed 2 months later, all cysticerci were exclusively recovered in the lungs from the mice with intravenous inoculation, but not with intramuscular injection. A high infection rate of 76% was obtained and a total of 45 cysticerci were collected from 50 mice. Thirty-five cysticerci were mature and with normal appearance but the rest were either with abnormal appearance (4) or degenerated (6). These findings give strong evidence that T. solium oncospheres may migrate to the normal mouse lung through venous circulation and develop in this organ.

Animals↗
PubMed2001

Characterization of an iridovirus from the cultured pig frog Rana grylio with lethal syndrome.

Three virus isolates, RGV-9506, RGV-9807 and RGV-9808, were obtained from cultured pig frogs Rana grylio undergoing lethal infections. Previously, the first isolate, RGV-9506, was shown to be an iridovirus based on ultrastructural and morphological studies. In the present study, the original isolate, along with 2 recent ones, were more extensively characterized by experimental infection studies, histopathology, electron microscopy, serological reactivity, gel electrophoresis of viral polypeptides and DNA restriction fragments, PCR amplification, and nucleic acid sequence analysis of the major capsid protein (MCP) gene. The 3 isolates were shown to be identical to each other, and very similar to FV3, the type species of the genus Ranavirus (family Iridoviridae). These results suggest that RGV should be considered a strain of FV3, and indicate that FV3-like iridoviruses are capable of causing widespread, severe disease among cultured frogs.

Amino Acid Sequence↗
PubMed2001

Giant Hall effect in nonmagnetic granular metal films.

Nearly 3 orders of magnitude enhancement in the Hall coefficient is observed in Cu(x)-(SiO(2))(1--x) granular films. This large enhancement of the Hall coefficient not only is significantly larger than the prediction of the classical percolation theory, but also occurs at a metal concentration identified to be the quantum percolation threshold. Measurements of the electron dephasing length and magnetoresistance, plus the TEM characterization of microstructures, yield a physical picture consistent with the mechanism of the local quantum interference effect.

Journal Article↗
PubMed2001

Characterization of oxyntic glands isolated from the rat gastric mucosa.

A simple and reproducible method for isolating oxyntic glands from the rat gastric mucosa was developed. The mucosa was incubated with pronase and EGTA, and then treated mechanically to release glands that were separated from single cells by sedimentation. Parietal cells were identified by immunostaining using a monoclonal antibody against H,K-ATPase. The glandular cells appeared morphologically intact. By careful control of the conditions of gland isolation, long glandular structures comprising hundreds of cells surrounding the lumen were obtained. Intraperitoneal injection of Br-deoxyuridine in the rat 1.5 h before the isolation procedure resulted in glands with a labeling of cells in their neck region. The glands were viable, as demonstrated by their ability to respond to various hormones. Histamine dose-dependently stimulated the acid formation which was measured as the accumulation of [14C]aminopyrine. At 100 microM histamine the accumulation was increased 5-10-fold. At 100 nM, pentagastrin potentiated the histamine stimulated accumulation by approximately 40% but pentagastrin alone did not stimulate. The oxyntic glands obtained by the present procedure appear useful for studies on cell physiology, including regulation of acid secretion, cellular interactions, and possibly also differentiation and proliferation mechanisms since long glandular fragments that contained the proliferative zone could be isolated.

Animals↗
PubMed2001

[Production of transgenic lamb integrated with modified human anti-trypsin gene].

This experiment is to produce the human mAAT(modified anti-trypsin) which cures the emphysema specifically through mammalian galactophore of transgenic goat. 56 goats were selected as donor for superovulation by FSF + LH microinjection in this experiment. The pronucleic embryos were injected with human mAAT gene after fertilization in vivo, and transferred to the donors or receptors directly. The superovulation was better in March and May than in December with the number of ovulation of 19.50, 21.70 and 16.06, and number of fertilized embryos of 4.31, 6.48 and 3.57 per-animal respectively. The pregnant rates were 18.18% and 25% respectively after transferred to donors and receptors with natural estrus. The donors also can be used as the embryo receptor with no remarkable decrease of pregnant rate. 29 lamb were labored. 4 positive transgenic lamb were checked by PCR, PCR-Southern and Southern analysis. The integrated efficiency of foreign DNA was 13.79% with microinjection of high copy number of foreign DNA fragment.

Animals↗
PubMed2001

[Ameliorative effects of adrenomedullin on rat cardiac sarcoplasmic reticulum injured by isoproterenol].

Five indices were used to assess the degree of the ameliorative effects of adrenomedullin (Adm) in isoproterenol (ISO) induced injury of cardiac sarcoplasmic reticulum (SR) of rats: +/- LV dp/dtmax, SR Ca2+ uptake, Ca2+ release (in nmol/mg SR protein) and Ca(2+)-ATPase activity. Adm (5 x 10(-5) mol/L) was perfused into rat heart before cardiac function +/- LV dp/dtmax was determined. Cardiac SR was purified and SR Ca2+ uptake, Ca2+ release, Ca(2+)-ATPase activity, and 3H-ryanodine maximal binding (Bmax) were measured. After perfusion of Adm (5 x 10(-5) mol/L), the +LV dp/dtmax and -LV dp/dtmax in ISO injured heart were increased by 16.9% (2,135 +/- 281 vs 1980 +/- 302, P < 0.05) and 29.2% (1375 +/- 267 vs 1064 +/- 355, P < 0.05), respectively. Cardiac SR Ca2+ uptake and Ca2+ release were increased by 23.0% (15.0 +/- 1.4 vs 12.2 +/- 1.2, P < 0.01) and 43.5% (6.6 +/- 1.0 vs 4.6 +/- 0.6, P < 0.01), respectively. Ca(2+)-ATPase activity and 3H-ryanodine binding were increased by 23.0% (P < 0.01) and 42.2% (P < 0.05), respectively. It seems that Adm exerted a protective effect on cardiac function in injured rat heart by enhancing SR Ca2+ uptake and release, suggesting that Adm may play a therapeutic role in myocardial injury.

Adenosine Triphosphatases↗
PubMed2000

Isolation of a lethal rhabdovirus from the cultured Chinese sucker Myxocyprinus asiaticus.

A rhabdovirus was found to be associated with a lethal hemorrhagic disease in the cultured Chinese sucker Myxocyprinus asiaticus Bleeker. The rhabdovirus was amplified and isolated from the infected GCO (grass carp ovary) cells. In ultrathin sections of liver cells from the diseased fish, the virus particles exhibited the characteristic bacilliform morphology, and budded through vesicle membranes of the infected cells. The isolated rhabdovirus particles were found to have a bacilliform morphology with 2 rounded ends rather than a typical flat base. The virus particles were measured and ranged in size from 150 to 200 nm in length and 50 to 60 nm in diameter. Most other characteristics, including their size, extensive virus infectivity to fish cell lines, strong cytopathogenic effects, stability at high temperatures, vesicle formation in infected cells, structure protein electrophoretic patterns and the presence of an RNA genome, very closely resembled those of other fish rhabdoviruses. At present it is not known if this is a novel virus species or if it is an isolate of a known fish rhabdovirus. Until a confirmed identification can be made, we will temporarily refer to this virus as Chinese sucker rhabdovirus (CSRV).

Animals↗
PubMed2000

Characterization of a murine monoclonal antibody that mimics heparin-induced thrombocytopenia antibodies.

Antibodies to PF4/heparin can be demonstrated in almost all patients with heparin-induced thrombocytopenia/thrombosis (HIT/HITT) and in some persons exposed to heparin who do not have clinical manifestations. The role of anti-PF4/heparin antibodies in the pathogenesis of HIT/HITT has been difficult to establish because the antibodies found in serum are generally polyclonal and polyspecific. To circumvent this problem, we developed a murine monoclonal antibody (mAb) to human (h) PF4/heparin complexes. A monoclonal IgG(2bkappa )antibody (designated KKO) was identified that bound specifically to hPF4/heparin complexes. Maximal binding of KKO to hPF4/heparin complexes occurred at similar molar ratios of PF4:heparin observed for HIT/HITT antibodies. KKO also bound to hPF4 in association with other glycosaminoglycans. Platelet activation by KKO required heparin and was abrogated by blockade of FcgammaRIIA. In the presence of PF4, KKO bound to endothelial cells, but not to CHO cells lacking heparan sulfate proteoglycans. Variants of PF4 complexed to heparin were recognized equally well by KKO and HIT/HITT sera. KKO competes for binding with a subset of HIT/HITT antibodies that are relatively spared by mutations in the 3rd domain of PF4. The nucleotide and predicted amino acid sequences of KKO and RTO, a murine anti-hPF4 mAb that does not require heparin for binding, revealed no obvious relationship in either the heavy- or the light-chain immunoglobulin variable regions. These studies suggest that KKO recapitulates the antigenic and functional specificity of a subset of HIT/HITT antibodies and may, therefore, provide insight into the pathogenesis of thrombocytopenia and thrombosis in affected persons. (Blood. 2000;95:1533-1540)

Amino Acid Sequence↗
PubMed2000

Molecular characterization and PCR detection of a deletional HPFH: application to rapid prenatal diagnosis for compound heterozygotes of this defect with beta-thalassemia in a Chinese family.

Hereditary persistence of fetal hemoglobin (HPFH) is one of the hemoglobinopathies in which the fetal gamma-globin genes remain active in adult life. Most HPFHs are caused by a large deletion involving a variable extent of DNA segment on the beta-globin gene cluster. We report the molecular defects associated with a deletional HPFH, which has previously been described in Cambodians and Vietnamese, in two unrelated Chinese individuals. To define the sequence around the breakpoints of the deletion, both the deletion junction fragment and the normal DNA across the breakpoints were cloned by PCR and sequenced. We found that the 5' breakpoint is located between nucleotides 986 and 987 upstream from the startpoint of the beta-globin gene, which further confirmed the Southeast Asian (SEA) HPFH deletion previously determined, whereas the 3' breakpoint, which is clarified for the first time by us, lies approximately 2.3 kb downstream from the 3' HS1 site of the beta-globin gene. It is suggested that deletions were the result of a non-homologous recombination event. Based on our novel sequence data, we designed a PCR amplification method with three primers bridging the 3' breakpoint. With this method and reverse dot blot (RDB) for detecting beta-thalassemia mutations, a Chinese family that had a 6-year-old propositus with severe thalassemia intermediate and that had requested prenatal diagnosis for the second pregnancy was found to be compound heterozygotes of HPFH defects with beta-thalassemia. The fetal genomic DNA diagnosis showed the same results as those in propositus, i.e., both of them inherited the deletion from their mother and inherited a codons 14-15 (+G) frameshift mutation causing beta-thalassemia from their father.

Adult↗
PubMed1998

Defining an antigenic epitope on platelet factor 4 associated with heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is a potentially serious complication of heparin therapy. Antibodies to platelet factor 4 (PF4)/heparin complexes have been implicated in the pathogenesis of this disorder, but the antigenic epitope(s) on the protein have not been defined. To address this issue, we studied the binding of HIT antibodies to a series of recombinant proteins containing either point mutations in PF4 or chimeras containing various domains of PF4 and the related protein, neutrophil activating peptide-2 (NAP-2). Serum samples from 50 patients with a positive 14C-serotonin release assay (14C-SRA) and a clinical diagnosis of HIT and 20 normal controls were studied. HIT antibodies reacted strongly with wild-type (WT) PF4/heparin complexes, but reacted little, if at all, with NAP-2/heparin complexes (optical density [OD]405 = 2.5 and 0.2, respectively). Alanine substitutions at three of the four lysine residues implicated in heparin binding, K62, K65, and K66, had little effect on recognition by HIT antibodies (OD405 = 2.2, 2.8, and 2.0, respectively), whereas an alanine substitution at position K61 led to reduced, but still significant binding (OD405 = 1.0). Similar studies involving chimeras between PF4 and NAP-2 localized a major antigenic site to the region between the third and fourth cysteine residues for more than half of the sera tested. This site appears to involve a series of amino acids immediately after the third cysteine residue beginning with P37. Thus our studies suggest that whereas the C-terminal lysine residues of PF4 are important for heparin binding, they do not comprise a critical antigenic site for most HIT antibodies. Rather, we propose that maintaining a region near the third cysteine residue of PF4, distal from the proposed heparin-binding domain, is required to form the epitope recognized by many HIT antibodies.

Amino Acid Sequence↗
PubMed1997

Detection of spiral and coccoid forms of Helicobacter pylori using a murine monoclonal antibody.

Helicobacter pylori is the major cause of gastritis. The aim of this investigation was to develop a specific antibody, which recognizes both coccoid and spiral forms of Helicobacter pylori and to test this antibody on gastric biopsy sections known to harbour coccoid bacteria. Murine monoclonal antibodies against glycine-acid extracts of five strains of Helicobacter pylori were raised. Immunofluorescence and immunoelectron microscopy showed that one antibody of the IgG1 subclass was specific for both the spiral and coccoid forms. It reacted with a 28 kDa protein that was present in all the five strains tested. Using this antibody in an indirect immunofluorescence assay of formalin-fixed antral and corpus biopsy specimens from Helicobacter pylori-associated gastritis patients showed that nine of the nine antral and five of six corpus specimens harboured the coccoid form of Helicobacter pylori. This technique thus provides a rapid and specific detection of both the spiral and coccoid forms.

Antibodies, Bacterial↗
PubMed1997

Highly selective iodide poly(vinyl chloride) membrane electrode based on a nickel(II) tetraazaannulene macrocyclic complex.

A PVC membrane electrode based on a nickel(II) tetraazaannulene macrocyclic complex as the carrier is described. The electrode exhibits an anti-Hofmeister selectivity sequence with a preference for iodide at pH 3.0-4.0. It has a linear response to iodide from 8.0 x 10(-6) to 1 x 10(-1) mol dm-3 with a slope of -54.7 +/- 0.2 mV per decade (20 degrees C), a satisfactory reproducibility and a rapid response time. The pH dependence of the potential response is discussed. The response mechanism of the electrode was investigated by ac impedance, quartz crystal microbalance and spectroscopic techniques. The electrode can be used for the determination of iodide in drug preparations.

Heterocyclic Compounds↗