Search PubMed⌕ Search

Biomedical subjects

Zhi Liu

Publications and source records attributed to Zhi Liu.

At least 73 records · Page 4Linked to original sources
PubMed2005

[Spectroscopic studies on different chemical composition between the shell and core of Radix Notoginseng].

Notoginseng (Sanqi) is one of the most important components of famous Chinese recipe (Yunan Baiyao) and possesses a wide variety of applications in clinical practice. It has been found that Sanqi of different size exhibits different curative effects. Such a phenomenon may be attributed to that the chemical constituent from shell region is different from that of core region. To prove the above-mentioned hypothesis, Ultraviolet-Visible (UV-Vis), FTIR, fluorescence spectroscopy, together with high performance liquid chromatography (HPLC) and electrospray ionization mass spectroscopy (ESI-MS) were utilized to study the variation of chemical compositions from shell and core regions of Sanqi. The results demonstrate that the chemical compositions of Sanqi from shell and core regions are different. In summary, differences in chemical composition between Sanqi shell and core were manifested from versatile aspects. Such differences shed a light on the different curative effects of Sanqi.

Chromatography, High Pressure Liquid↗
PubMed2005

[Characteristic manifestations of neuropsychiatric systemic lupus erythematosus].

OBJECTIVE: To investigate the characteristic manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE) in clinical practice. METHODS: A total of 198 NPSLE cases from 1998 to 2003 in Peking Union Medical College Hospital, were included. Their clinical manifestations and the results of accessory examination such as serology, lumbar puncture, head magnetic resonance imaging, and electroencephalogram were analyzed. RESULTS: The most frequent manifestations of the NPSLE included: headache, psychiatric disorder, seizure, stroke, and acute confusional state. Fifty-two patients took head magnic resonance imaging, and 34 of them showed abnormal, including stroke attack. Among 48 patients who only had a complaint of headache, the increase of intracranial pressure and cerebral spinal fluid protein was significantly higher than other NPSLE syndromes (P < 0.05). CONCLUSION: Diagnosis of NPSLE was mainly based on its clinical manifestations. Head magnetic resonance imaging and cerebral spinal fluid examination may be helpful. More specific accessory examinations require further development.

Adult↗
PubMed2005

[Isolation and functional identification of delta 5 desaturase gene from Mortierella alpina].

Arachidonic acid is an essential fatty acid in human nutrition and a biogenetic precursor of the biologically active prostaglandins and leukotrienes. delta5 desaturase is a key enzyme in the biosynthetic pathway of arachidonic acid, which catalyze the delta5 dehydrogenation of di-homo-gamma-linolenic acid to form arachidonic acid. Complete cDNA encoding putative delta5 fatty acyl desaturase was isolated from Mortierella alpina M6 via RT-PCR. The full length cDNA consisted of 1366 nucleotides encoding 446 amino acids. The deduced protein had conserved domains of known delta5 fatty acyl desaturases including a cytochrome b5 domain in the N terminal and 3 conserved histidine box. To elucidate the function of the protein, the cDNA was subcloned into the expression vector pPIC9K. The resultant recombinant plasmid pPIC9K-D5 was transformed to Pichia pastoris GS115 by electroporation. Transformants containing multi-copy delta5 desaturase gene were screened by Geneticin resistance. The transformants were induced to express the inserted gene with methanol when di-homo-gamma-linolenic acid was provided as an exogenous substrate. Analysis of the recombinant yeast lipids by gas chromatograph showed that a novel peak corresponding to the standard of arachidonic acid was detected. The novel peak was further characterized by GC-MS and identified as arachidonic acid. The results showed that the gene isolated from fungi Mortierella alpina M6 was a delta5 desaturase gene.

Amino Acid Sequence↗
PubMed2005

[Experimental study of tracheal defect repair with shape-memory titanium-nickel alloy net].

OBJECTIVE: To investigate the feasibility of trachea defect repair with "C" shape shape-memory titanium-nickel alloy net (CSSMAN). METHOD: The CSSMAN substitute for the tracheal cartilage and the skin tube for the tracheal mucosa in order to form a new "trachea" shape structure to repair the mongrel dogs trachea defect. RESULT: Four dogs were successfully decannulate, computerized tomography (CT) examination and fibrotracheoscopy examination showed the CSSMAN located perfectly and the airway is wide enough for breath. One dog failed to decannulate due to the infection. CONCLUSION: It is a promising choice to repair the trachea defect with CSSMAN by two-stage procedure.

Alloys↗
PubMed2005

[Effects of different point association needling methods on IL-1, sICAM-1 and sVCAM-1 in the patient of cerebral infarction].

OBJECTIVE: To observe effects of acupuncture on serum interleukin-1 (IL-1) and soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) in the patient of cerebral infarction. METHODS: Eighty-two cases of cerebral infarction were randomly divided into a treatment group treated by balanced muscular tension needling method, and a control group by traditional needling method. The levels of serum IL-1, sICAM-1 and sVCAM-1 were determined with enzyme-linked immunosorbent assay (ELISA). RESULTS: The levels of serum IL-1, sICAM-1 and sVCAM-1 in the patient of cerebral infarction were significantly higher than those in the healthy persons (P < 0.01); there were positive correlation between sICAM-1 or sVCAM-1 level and IL-1 level (r = 0.743, P < 0.001; r = 0.862, P < 0.001). The three indexes improved to a certain extent in the two groups, with the treatment group superior to the control group (P < 0.01). CONCLUSION: The improvement of nervous function by the balanced muscular tension needling method in the patient of cerebral infarction is possibly related with decrease of IL-1, sICAM-1 and sVCAM-1 levels.

Cerebral Infarction↗
PubMed2005

[The studies on YCl3/PEU system by rheology analysis and FTIR].

FTIR spectroscopy and rheology analysis were applied to study the YCl3/PEU system. It is apparent that modification with lanthanide complexes such as yttrium leads to a slight increase in viscosity of the polyether urethane solution. The authors conclude that this may be due to the interaction between the lanthanide ions and the polar group in urethane.A new band appears at 1650 cm(-1) in the infrared spectra of the YCl3/PEU system, which corresponds to the new carbonyl structure formed through the coordination with yttrium cations. The dynamic rheological behaviors of the solutions demonstrate the interaction furthermore. A higher molecular weight formed with the higher concentration of the lanthanide ions in this DMF solution. And this could be an effective method to characterize the structure of the polymer solutions.

English Abstract↗
PubMed2004

Bullous pemphigoid: using animal models to study the immunopathology.

Bullous pemphigoid was first described by Lever in 1953 as a subepidermal blistering disease. Its immunohistological features include dermal-epidermal junction separation, an inflammatory cell infiltrate in the upper dermis, and basement membrane zone-bound autoantibodies. These autoantibodies show a linear staining at the dermal-epidermal junction, activate complement, and recognize two major hemidesmosomal antigens, BP230 (BPAG1) and BP180 (BPAG2 or type XVII collagen). An IgG passive transfer mouse model of BP was developed by administering rabbit antimurine BP180 antibodies to neonatal mice. This model recapitulates the key features of human bullous pemphigus. Using this in vivo model system, several key cellular and molecular events leading to the bullous pemphigus disease phenotype were identified, including IgG binding, complement activation, mast cell degranulation, and neutrophil infiltration and activation. Proteinases and reactive oxygen species released by neutrophils work together to damage the basement membrane zone, causing dermal-epidermal junction separation. Recent experimental data from human bullous pemphigus studies suggest that human bullous pemphigus and its mouse IgG passive transfer model counterpart may well share not only common immunohistological features but also pathological mechanisms underlying the development of this antibody-mediated disease.

Amino Acid Sequence↗
PubMed2004

Accurate representation of the hepatitis C virus quasispecies in 5.2-kilobase amplicons.

Hepatitis C virus (HCV) exists as a swarm of genetically distinct but related variants, or a quasispecies, whose complexity and sequence evolution are critical to studies of viral pathogenesis. Because most studies of the HCV quasispecies have focused on a relatively small genomic segment, the first hypervariable region of the E2 gene, it is possible that viral complexity is occasionally underestimated (due to primer mismatch) and that sequence evolution is misperceived due to unrecognized covariation. This report describes a sensitive and reproducible method to amplify most of the HCV genome as a single 5.2-kb amplicon by using primers directed at relatively conserved genomic segments. Using 52 specimens obtained during acute infection over a range of viral RNA concentrations, the overall rate of successful amplification was 94% and varied in a concentration-dependent manner, with successful amplification in 26 of 26 (100%) specimens at greater than 10(5) IU/ml, 15 of 16 (94%) at 10(4) to 10(5) IU/ml, 6 of 7 (86%) at 10(3) to 10(4) IU/ml, and 2 of 3 (67%) at less than 10(3) IU/ml. Quasispecies complexity, determined by using this novel long-amplicon method followed by heteroduplex mobility assay combined with single-stranded conformational polymorphism (HDA+SSCP) analysis, was very high, even during acute HCV infection, when 10 to 21 (median, 16) different HDA+SSCP patterns were detected among 33 cDNA clones examined. Replicate analyses indicate that this diversity is not dominated by random errors generated during amplification. Therefore, the HCV quasispecies is highly complex even during acute infection and is accurately represented in amplicons representing more than half of the viral genome.

Amino Acid Sequence↗
PubMed2004

[Determination of orientin and vitexin in Trollius chinesis preparation by HPLC].

OBJECTIVE: To establish a HPLC method for determining orientin and vitexin in Trollius chinesis preparation. METHOD: The separation was carried out on Hypersil ODS column with a mixture of acetonitrile-1% acetic acid solution (15:85) as the mobile phase, at a flow rate of 1.0 mL x min(-1). The detection wavelength was set 340 nm. RESULT: Orientin showed a good linear relationship in the range of 8.42-84.2 microg x mL(-1) (r = 0.9999) and the average recovery is 98.3%, RSD is 0.8%. Vitexin showed a good linear relationship in the range of 8.07-80.7 microg x mL(-1) (r = 0.9999) and the average recovery is 102.4%. RSD is 1.7%. CONCLUSION: The method is sensitive, specific, and accurate with a good repeatability and can be used for the quality control of Trollius chinesis preparation.

Apigenin↗
PubMed2004

[Protection of artesunate on activation and injury of vascular endothelial cells induced by lipopolysaccharide].

OBJECTIVE: To investigate the protective effects and mechanism of artesunate (AR) on the activation and injury of human umbilical vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS). METHODS: After HUVECs were cultured and turned to fusion manner, LPS and different concentration of AR (0.04 mg/L, 0.2 mg/L, 1 mg/L, 5 mg/L and 20 mg/L) were added respectively and co-incubated for 24 hrs. The expression of von Willebrand factor (vWF) in the conditioned media was tested by ELISA, the expression of intercellular adhesion molecule (ICAM-1) protein was determined by Western blot method and the expression of tumor necrosis factor alpha (TNFalpha) mRNA was determined by in situ hybridization. RESULTS: After being exposed to 1 microg/ml LPS, vWF and ICAM-1 expression were higher than those in the control group. AR could significantly down-regulate the increased expressions concentration-dependently, significant difference showed as the concentration of AR reached 1 mg/L (P < 0.05). In situ hybridization showed that AR in 0.2 mg/L and 1 mg/L could markedly down-regulate the TNFalpha mRNA expression, showing significant difference as compared with that in LPS group (P < 0.05, P < 0.01). CONCLUSION: AR has protective effect on LPS induced HUVECs activation and injury, which might be related with its inhibition on TNFalpha mRNA expression.

Artemisia↗
PubMed2004

Vascular endothelial injuries and changes of blood coagulation and fibrinolysis indexes in patients with acute respiratory distress syndrome.

OBJECTIVE: To study endothelial damage by observing changes of circulating endothelial cells (CECs) in blood, coagulation and fibrinolysis index in patients with acute respiratory distress syndrome. METHODS: CECs were separated by isopycnic centrifugation method in 14 patients with acute lung injury (ALI), 7 patients with acute respiratory distress syndrome (ARDS), 10 intensive care unit (ICU) controls, and 15 healthy controls. Plasma prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FG), fibrin degradation products (FDP), and D-dimer were examined simultaneously. Acute physiology and chronic health evaluation (APACHE) II and lung injury score (LIS) were recorded to evaluate severity of illness and lung injury. RESULTS: (1) The number of CECs in ALI (10.4 +/- 2.3) and ARDS groups (16.1 +/- 2.7) was higher than that in the healthy (1.9 +/- 0.5) (P < 0.01). In both ALI and ARDS, the number of CECs correlated with APACHE II (r = 0.55, P < 0.05 and r = 0.62, P < 0.05, respectively) and LIS (r = 0.60, P < 0.05 and r = 0.53, P < 0.05, respectively). CEC number was negatively correlated with PaO2 in ALI and ARDS (r = -0.49, P < 0.05 and r = -0.64, P < 0.05, respectively). (2) The level of FDP and D-dimer were higher in ALI and ARDS patients than that in ICU and healthy control groups (P < 0.05). The level of FG in ARDS group was significantly higher than in the ICU and healthy control groups (P < 0.05). But in ALI group, the level of FG was significantly higher than only healthy control group (P < 0.05). CONCLUSIONS: Endothelial cell damage occurs in ARDS patients, which may play a major role in the pathophysiology of ARDS. Changes of endothelial cell activation and damage markers, such as CECs, plasma coagulation and fibrinolysis index, to some extent reflect severity of illness and lung injury in ARDS.

APACHE↗
PubMed2004

[The interaction between La and polyurethane system].

A series of polyether polyurethane (PU)-LaCl3 composites with different lanthanum contents were prepared. DSC results indicate that LaCl3 promotes phase transition behavior of the LaCl3/PU composites, which causes the endothermic peak at 11.58 degrees C to disappear. FTIR spectroscopy demonstrates that significant variation can be observed. The peak at 1633 cm(-1) attributed to carbonyl vibration and the peak at 3311 cm(-1) attributed to N-H stretching band moves to 1647 cm(-1) and 3355 cm(-1), respectively, when LaCl3 is introduced into the PU system. A new band (-200 cm(-1)) assigned to the La-O band was observed, and the far IR result provided a direct evidence of the coordination between La3+ ion and C=O group of PU system.

English Abstract↗
PubMed2004

[Cloning and analysis of cDNA encoding key enzyme gene (dxr) of the non-MVA pathway in Taxus chinensis cells].

Two distinct routes (classical mevalonate pathway and a novel mevalonate-independent pathway) are utilized by plants for the biosynthesis of isopentenyl diphosphate, the universal precursor of isoprenoids (Fig. 1). Present researches indicated that taxol was synthesized mainly via non-mevalonate pathway, but not genetic evidence was showed. The second step in non-mevalonate pathway involves an intramolecular rearrangement and subsequent reduction of deoxyxylulose phosphate to yield 2-C-methyl-D-erythritol-4-phosphate, and 1-Deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) with responsibility for this reaction was considered as a key enzyme. As a tool for the isolation of genes in terpenoid biosynthesis in plants, total RNA was prepared from Taxus chinensis suspension cells, a cell type highly specialized for diterpene (taxol). A reverse transcription-PCR strategy based on the design of degenerated oligonucleotides was developed for isolating the gene encoding a gymnosperm homolog of this enzyme from Taxus chinensis. Through sequence analysis by Blast P online, the resulting cDNA showed highly homologous to 1-deoxy-D-xylulose 5-phosphate reductoisomerases, with 95% identification compared with Arabidopsis thaliana (Q9XFS9), 94% with Mentha x piperita (Q9XESO), 80% with Synechococcus elongatus (Q8DK30), 78% with Synechocystis sp. PCC 6803 (Q55663) and Nostoc sp. PCC 7120 (Q8YP49), and 73% with Synechococcus leopoliensis (Q9RKT1). Deduced amino acid sequences were also analyzed by PROSITE, ClustalX (1.81) and Phylio (3.6 alpha), and data present evidence for the existence of this deoxyxyluose phosphate reductoisomerase in Taxus chinensis. This is the first report of the dxr gene cloned from gymnosperm.

Aldose-Ketose Isomerases↗