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Biomedical subjects

Qi Zhang

Publications and source records attributed to Qi Zhang.

At least 91 records · Page 5Linked to original sources
PubMed2006

[Studies on the interaction of the metal complex of hydrazide of podophyllic acid with DNA].

The interaction between the metal complex of hydrazide of podophyllic acid and calf thymus (CT) DNA was studied by using absorption spectra, fluorescence spectra and DNA heat denaturation. It was found that the intensity of the maximal absorption peaks from absorption spectra is weakened in the presence of the metal complex of hydrazide of podophyllic acid compared with that in the absence of the metal complex. All the experimental results show that the intercalation mode was proved to exist between HDPP-Ni complexes and CT DNA.

Animals↗
PubMed2006

[Effect of Rho kinase on hypoxia stimulated proliferation of pulmonary arterial smooth muscle cells].

OBJECTIVE: To study whether Rho kinase is involved in the proliferation of pulmonary arterial smooth muscle cells (PASMCs) induced by hypoxia. METHODS: Rat's PASMCs were isolated and cultured. Methyl thiazolyl tetrazolium (MTT) was used to determine the growth of cells. The cell cycle was analyzed by flow cytometry. Western blot was used to assess the expression of Rho kinase. RESULTS: The results of MTT showed that the number of PASMCs was increased after exposure to low oxygen tension for 12 hours compared with PASMCs in normoxia. After exposure of PASMCs to hypoxia for 24 hours,the cellular proliferation peaked,and was higher than that of PASMCs exposed to normal oxygen tension, hypoxia and Y27632 (Rho kinase inhibitor) groups,then it declined when exposed for 48 hours. Analysis of cell cycle indicated that the ability of cell proliferation increased significantly in PASMCs exposed to hypoxia compared with normoxia. Rho kinase level was higher in PASMCs exposed to hypoxia compared with normoxia. CONCLUSION: Hypoxia stimulates proliferation of PASMCs and promotes PASMCs into the phase of mitosis. The expression of Rho kinase is increased in PASMCs that are exposed to hypoxia, and it shows that Rho kinase is activated by hypoxia in PASMCs. Rho kinase maybe involve in the proliferation of PASMCs induced by hypoxia.

Animals↗
PubMed2006

[Studies on the mechanism of the interaction between hydrazide-podophyllic Ni(II), Co(II), Zn(II) metal complexes and DNA].

The mechanism of the interaction between hydrazide-podophyllic (HDPP) metal (Me) complexes and calf thymus (ct) DNA in Tris buffer (pH 7.08) was studied by viscosity measurements, electronic absorption, gel electrophoresis, and ethidium bromide (EB) fluorescence spectroscopy. The results from varied experiments show that the intensity of the maximal absorption peaks from absorption spectra is weakened in the presence of DNA compared with that in the absence of DNA. Meanwhile, DNA can remarkably quench the emission intensity of the complex Me-HDPP system. The Me-HDPP complexes can increase the viscosity of ct DNA slightly and catalyze the cleavage of super coiled pBR322 DNA to the nicked form. The complexes of Ni-HDPP and Co-HDPP can be bound to ct DNA mainly by interaction, while the partial interaction of Zn-HDPP and ct DNA is the major modes. The binding constant of Me-HDPP complexes with ct DNA was determined.

DNA↗
PubMed2006

[Standardization of rat stable orthotopic liver transplantation model and comparison of the effect of two liver graft perfusion methods].

OBJECTIVE: To standardize the establishment of a stable rat model of orthotopic liver transplantation and surgical technique of two-cuff technique for improving the operation success rate, and compare the effect of graft perfusion via the portal vein and the abdominal aorta on the graft function. METHODS: Totally 100 cases of orthotopic liver transplantation was performed in rats under microscope according to modified Kamada's two cuff technique. The rats were divided into 2 groups with the donor liver perfused through the portal vein with 10 ml cold lactated Ringer's solution, and via the abdominal aorta with 20 ml cold lactated Ringer's solution, respectively. The postoperative function recovery and pathological changes of the liver grafts were evaluated by serum ALT detection and histopathological examination. The operation success rate, 3-month survival rate of the rats and the complications were observed. RESULTS: No significant differences was noted in the liver function, operation success rate and 3-month survival rate between the 2 groups, and histopathological examination also showed similar findings. The success rates of the two groups were 98% and 96%, with 3-month survival rate of 93.5% (29/31) and 93.3% (28/30) (P>0.05), respectively. CONCLUSION: The liver transplantation models with portal vein or abdominal aorta graft perfusion both serve well their respective purposes. Good microsurgical skills, standardized performance and shortened anhepatic period are the keys to improved stability and survival rate and reduced operative complications.

Animals↗
PubMed2006

[Atopy spectrum and its relationship with clinical characteristics in asthmatic children under 4 years of age].

OBJECTIVE: To study the atopy spectrum and the influence of clinical characteristics upon it in asthmatic children under 4 years of age. METHODS: Clinical data of 62 asthmatic children under 4 years of age, including age, sex, the age of first wheezing attack, the total times of wheezing attack, the duration of history of wheezing, and the allergic history of both children and parents, were collected. The screening tests on allergens (fx5E, mx2 and Phadiatop) were conducted by fluoroenzyme-immunometric assay using the UniCAP100 system. The total serum IgE level was also measured. Logistic regression was used to analyze the effect of clinical characteristics on allergic sensitization. RESULTS: The positive rates of fx5E, mx2 and Phadiatop were 40.3%, 14.5% and 14.5% respectively, and the total allergic sensitization screening test rate was 46.8%. The sensitization rate to inhalant allergens was 24.2%. The allergic history of parent (s), the sensitization to food allergens, the age of first wheezing attack and total serum IgE level were main factors influencing the sensitization to inhalant allergens. CONCLUSIONS: About a quarter of asthmatic children under 4 years of age showed sensitization to inhalant allergens. The asthmatic history of parent (s), the sensitization to food allergens, the age of first wheezing attack greater than 2 years and the significantly higher total serum IgE level may increase the possibility of sensitization to inhalant allergens in asthmatic children under 4 years of age.

Allergens↗
PubMed2006

[Structure and performance of calcium polyphosphate for bone tissue engineering].

Porous calcium polyphosphate (CPP) has shown promise of tissue engineered implant application because of the biocompatibility and biodegradation. CPP with different polymerization degree were prepared by controlling the calcining time, and its polymerization degree could be calculated by developed method in this paper. Different crystal types CPP were prepared by quenching from the melt and crystallization of amorphous CPP. From the in vitro degradation, carried out in Tris-HCl buffer, the degradation velocity of CPP was controllable. The weight loss of CPP with different polymerization degrees and crystal types were different. With the increasing of polymerization degree, the weight loss during the degradation was decreasing, contrarily the strength of CPP was increasing. The amorphous CPP could degrade completely in 17 days while gamma-CPP do completely in 25 days. The degradation velocity beta-CPP and alpha-CPP was slower than gamma-CPP and the weight loss was about 12% and 5% respectively. The results of this study indicate that CPP have potential applications for bone tissue engineering as inorganic polymeric biomaterials.

Absorbable Implants↗
PubMed2006

[Study on allergenicity of fresh HAM for type I hypersensitivity].

To investigate whether human amniotic membrane (HAM) preparations have the possibility to type I hypersensitivity and its allergenicity. In systemic active allergic test model, 30 guinea pigs were equally divided into three groups. Each 10 guinea pigs were immunized with fresh HAM homogenate, albumen solution (positive control) and PBS (negative control). After the animals were stimulated with corresponding allergen, observe their reaction till dying or 3 h, then obtain blood samples, to determine blood histamine concentrations using chemical fluorometry and four hemorheologic markers by hemorheology analysis system. The guinea pigs responded to fresh HAM homogenate in almost the same manner as to PBS, and no obvious allergic reaction was observed in the animals except those in positive control group. The blood histamine concentration and four hemorheologic markers showed no significant differences between HAM and PBS (P > 0.05), both were much lower than positive control group (P < 0.01). Fresh HAM won't lead to type I hypersensitivity for lack of allergen performance.

Allergens↗
PubMed2005

[Cell-cycle negative regulatory gene ANA is over-expressed in the brain tissues of patients with Down syndrome].

OBJECTIVE: To investigate the expression level of genes located in chromosome 21 in the brain tissues of Down syndrome(DS). METHODS: An optimized semi-quantitative RT-PCR method was used to evaluate the expression levels of seven genes encoded in chromosome 21 in fetal cortex brain and cerebellum of DS and the control at the end of 20 weeks of gestation. B2M was used as internal reference to normalize cell loss. RESULTS: The expression levels of 6 genes in cortex and cerebellum, including DYRK1A, SYNJ1, PCP4, C21orf5, C21orf2 and C21orf106, were comparable between DS and the control. ANA, a cell-cycle negative regulatory gene, was over-expressed dramatically in the cortex but not in the cerebellum of DS. CONCLUSION: Over-expression of ANA may contribute to the reduction of neuronal density in DS brain.

Brain↗
PubMed2005

Intranasal recombinant human erythropoietin protects rats against focal cerebral ischemia.

Erythropoietin (EPO) is a hematopoietic growth factor with tissue-protective properties, and can protect animals from cerebral ischemic injury. However, the central nervous effects of EPO as a glycoprotein is limited by the potential complication resulted from its erythropoietic activity and the problem of the penetration through blood-brain barrier (BBB). To avoid these limitations, in this study we administered recombinant human EPO (rhEPO) intranasally (i.n.) to evaluate its neuroprotective effect in the rats with focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO). We found that rhEPO i.n. at doses of 4.8, 12 and 24 U (administered 10 min after MCAO and 1h after reperfusion) reduced infarct volume, brain swelling and cell damage in the ischemic hemispheres, and improved behavioral dysfunction 24 h after cerebral ischemia. Intraperitoneal rhEPO (5000 U/kg) also showed the protective effect, but the heat-inactivated rhEPO did not show any effect. Thus, intranasal administration of relatively small doses of rhEPO protects rats from acute injury after focal cerebral ischemia, suggesting that intranasal rhEPO may be a more effective and safer administration route for treatments of ischemic or other brain diseases.

Administration, Intranasal↗
PubMed2005

Addition of calcite reduces iron's bioavailability in the Pennsylvania coals--potential use of calcite for the prevention of coal workers' lung diseases.

In the present study, a hypothesis was tested that the addition of calcite into the Pennsylvania coals may reduce levels of bioavailable iron (BAI), an important component in the mixed coal dust that may contribute to coal workers' lung diseases. Predetermined proportions of calcite (0, 1, 2, 5, 10% w/w) were added into three PA coals. After suspending the mixtures in an aqueous phosphate solution (10 mM, pH 4.5), which mimics the phagolysosomal conditions of the cells, levels of pH as well as calcium ions (Ca2+) in the coals were increased in a calcite concentration-dependent manner. In contrast, levels of BAI (both Fe2+ and Fe3+) were decreased. The inhibitory effects of calcite on the bioavailability of iron in human lung epithelial A549 cells and primary rat alveolar macrophages (AMs) were also examined. It was found that levels of low-molecular-weight (LMW) iron were significantly decreased in both A549 cells and AMs treated with the 10% calcite-PA coal mixture compared to those treated with the PA coal alone, while calcite itself had no effect on intracellular LMW iron. Calcite also showed a significant inhibitory effect on PA coal-induced ferritin synthesis in A549 cells. Reverse-transcription polymerase chain reaction (RT-PCR) studies revealed that the iron-containing PA coal downregulated levels of transferrin receptor (TfR) mRNA in A549 cells, which was partially restored by the addition of calcite. Our results indicate that calcite can inhibit the bioavailability of iron in the iron-containing PA coals.

Animals↗
PubMed2005

Local application of morphine suppresses glutamate-evoked activities of C and Adelta afferent fibers in rat hairy skin.

Behavior studies have demonstrated that local application of morphine in peripheral tissues resulted in a significant antinociceptive effect, but there has been no electrophysiological evidence to support the peripheral mechanism of opioid antinociception. The purpose of the present study was to investigate whether local application of morphine suppressed the glutamate-evoked activities of C and Adelta primary afferent fibers in dorsal hairy skin of rat in vivo. The single unit activities of the C and Adelta afferent fibers were recorded by means of isolation of the fiber filaments from the dorsal cutaneous nerve branches, and the effects of glutamate and glutamate plus morphine injected into the receptive field on these activities were determined. The results revealed that most of the C and Adelta fibers were excited significantly by local injection of glutamate (0.3 mM), with the percentage being 81% (22/27, for C fibers) and 73% (36/49, for Adelta fibers), respectively. The glutamate-induced excitatory response was significantly suppressed by co-injection of morphine (1.0 mM). The mean discharge rates of C fibers and Adelta fibers decreased from 28.96 +/- 6.85, 28.99 +/- 3.79 impulses/min to 4.40 +/- 1.76, 2.72 +/- 0.71 impulses/min, respectively. The suppressing effect of morphine was reversed by pretreatment with opioid receptor antagonist naloxone (1.0 mM). These findings suggest that local application of morphine can suppress the glutamate-evoked activities of the fine fibers in rat hairy skin and thus provide an electrophysiological evidence for peripheral antinociception of opioids.

Action Potentials↗
PubMed2005

Determination of promethazine hydrochloride and its preparations by highly accurate nephelometric titration.

A highly accurate nephelometric titration for the determination of promethazine hydrochloride and its preparations was presented. The titration operating conditions were studied and the solubility product constant of promethazine tetraphenylboron precipitation was determined. The result of the titration is comparable to those of control experiments. The proposed method has been found to be accurate, precise, specific and linear.

Nephelometry and Turbidimetry↗
PubMed2005

Single-crystalline GdB6 nanowire field emitters.

Having the lowest work function in the rare-earth hexaboride family, GdB6 nanowires of rectangular cross-section with about 50 nm in lateral dimension and several microns in length have been successfully produced using a CVD method. The nanowires are grown in the 001 lattice direction, and both the tip-top and the side surfaces are terminated with the {100} lattice planes. A GdB6 single nanowire field emitter has also been built with an emission current of more than 150 nA at an applied field of less than 3.2 V/mum. The work function of the nanowire emitter was estimated to be about 1.5 eV.

Boron↗
PubMed2005

Simultaneous determination of loratadine and pseudoephedrine sulfate in human plasma by liquid chromatography-electrospray mass spectrometry for pharmacokinetic studies.

To support the pharmacokinetic and bioavailability study of an extended-release loratadine (LOR)/pseudoephedrine sulfate (PES) tablet, a high performance liquid chromatographic-electrospray ionisation-mass spectrometric method (LC-MS) was developed for the simultaneous determination of LOR and PES in human plasma. Diazepam (DP) and phenylpropanolamine (PPA) were used as internal standards for LOR and PES, respectively. Analytes were extracted from alkalized human plasma by liquid/liquid extraction using ethyl ether. Chromatographic separation was performed on an ODS column at flow rate of 0.2 ml/min. The total chromatographic run time was 10.5 min with the retention time of 7.1 min and 6.2 min for LOR and DP, respectively, and 2.2 min for both of PES and PPA. The LOQ was 10 pg/ml and 50 pg/ml for LOR and PES, respectively. The method is accurate and precise enough for its intended purpose.

Calibration↗
PubMed2005

Pranlukast, a cysteinyl leukotriene receptor-1 antagonist, protects against chronic ischemic brain injury and inhibits the glial scar formation in mice.

We have recently reported the neuroprotective effect of pranlukast (ONO-1078), a cysteinyl leukotriene receptor-1 (CysLT1) antagonist, on cerebral ischemia in rats and mice. In this study, we further determined whether the effect of pranlukast is long lasting and related to the formation of a glial scar in cerebral ischemic mice. Focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). After ischemia, pranlukast (0.1 mg/kg) was injected intraperitoneally for 5 consecutive days. Neurological deficits and sensorimotor function were determined during 70 days after ischemia. Brain lesion and glial scar formation were detected at the end of the experiment. Pranlukast did not reduce mortality, but significantly improved neurological deficits and promoted sensorimotor recovery during 70 days. At the end of the experiment, pranlukast significantly reduced lesion volume, and increased neuron densities in the cortex and hippocampal CA1 region in the ischemic hemispheres. Importantly, pranlukast also remarkably reduced the thickness of a scar wall in the ischemic hemispheres. These findings indicate that pranlukast has a long-lasting protective effect on focal cerebral ischemia in mice, and inhibit the ischemia-induced glial scar formation, providing further evidence of the therapeutic potential of pranlukast in the treatment of ischemic stroke.

Analysis of Variance↗
PubMed2005

[Residual stomach, duodenum, and continual jejunal interposition after subtotal gastrectomy].

OBJECTIVE: To investigate the clinical effect of residual stomach, duodenum, and continual jejunal interposition on the patients of gastric cancer after subtotal gastrectomy. METHODS: Fifty-four patients with gastric cancer after subtotal gastrectomy were randomly divided into 2 groups: Group A (n = 26, receiving digestive tract reconstruction by manual end-to-side anastomosis of residual stomach and jejunum, end-to-side anastomosis of residual duodenum and jejunum, and side-to-side anastomosis of jejunum and jejunum, then the jejunum proximal to the stomach-jejunum anastomosis and the jejunum distal to the duodenum-jejunum anastomosis were ligated so as to form an integral continual jejunal interposition; and Group B (n = 28, receiving Bilroth digestive tract reconstruction. The operation time, body weight, prognosis nutrition index (PNI), and Visick score 3 and 6 months after the operation were observed. RESULTS: All patients recovered quickly and no complicating anastomosis leakage and obstruction was found. It took 53 +/- 9 minutes to finish the reconstruction in Group A, significantly shorter than that in Group B (57 +/- 6 minutes, t = -2.145, P = 0.037). The body weight and PNI of both groups decreased significantly 3 months after the operation in comparison with those before the operation (both P < 0.05). The body weight and PNI of Group A returned to the levels before operation. Although the body weight and PNI of Group B recovered to some extent 6 months after operation, they remained significantly lower than those before operation both P < 0.05). The Visick score 6 months after operation of Group A was superior to that of Group B (t = 2.1 P < 0.05). CONCLUSION: Residual stomach, duodenum, and continual jejunal interposition after subtotal gastrectomy helps overcome the difficulty in the procedure of digestive tract reconstruction and restore the physiological passage through duodenum, thus avoiding reflux and improving patients' quality of life.

Adult↗
PubMed2005

Two triterpenoids and other constituents from Petasites tricholobus.

Two migrated ursane skeleton triterpenoids, one is D:B-friedoursane-3alpha,16alpha-dihydroxy-7alpha,8alpha-epoxy-5(10)-ene, named petatrichol A (1) and the other one represents a novel triterpenoid carbon framework, named petatrichol B (2), along with 10 known compounds were isolated from the rhizome of Petasites tricholobus. Their structures were elucidated on the basis of spectroscopic methods (IR, EIMS, HRMS, 1D and 2D NMR). The triterpenoids were assayed against Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Compounds 1 and 2 exhibited significant antibacterial activity against B. subtilis.

Anti-Bacterial Agents↗