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Biomedical subjects

X Liu

Publications and source records attributed to X Liu.

At least 433 records · Page 24Linked to original sources
PubMed2001

[Experimental study of protective effect of shenmai injection on endotoxin induced systemic inflammatory reaction syndrome and multiple organ dysfunction syndrome].

OBJECTIVE: To study the protective effect of Shenmai injection (SMI) on systemic inflammatory reaction syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) in animal model of SIRS, MODS induced by lipopolysaccharide (LPS). METHODS: Male BALB/c mice, 5-7 weeks old were randomly divided into 3 groups, the normal control group, the LPS model group and the LPS + SMI group. The rectal temperature, peripheral white blood cell count (WBC), blood biochemical examination, histopathologic changes of lung and liver as well as the blood levels of endotoxin and tumor necrosis factor alpha (TNF alpha) were determined before and after treatment. RESULTS: LPS could induce endotoxemia and high serum level of TNF alpha, decrease the rectal temperature and WBC, reduce blood glucose and increase serum triglyceride and cholesterol levels. Pathological examination showed that LPS could cause pulmonary alveolar congestion, edema, exudation, capillary dilation and inflammatory cell infiltration in liver and lung tissue. SMI could significantly raise the low body temperature caused by LPS and reduction of WBC, improve the hypoglycemia and high plasma TNF alpha level, alleviate the pathologic changes in organs and reduce the plasma level of LPS (endotoxin). CONCLUSION: SMI has marked effect in protecting LPS caused SIRS, MODS, the mechanism might be related with the lowering of LPS (endotoxin) level and reducing of TNF alpha secretion.

Animals↗
PubMed2001

[Pharmacokinetics and bioavailability of clinafloxacin in rats].

AIM: To study the pharmacokinetics and bioavailability of clinafloxacin in rats. METHODS: The drug concentration was determined by HPLC. The main pharmacokinetic parameters were obtained by 3P87 program. An RP-C18 was used as the stationary phase. The mobile phase was a mixture of acetonitrile-0.05 mol.L-1 citric acid triethylamine (pH 2.5) (20:80). The flow rate was 1.0 mL.min-1. The UV absorbance detector was set at 300 nm. RESULTS: A good linearity was obtained from 0.03-20 micrograms.mL-1 of clinafloxacin in rat plasma with gamma = 0.9998. The plasma concentration--time curve of clinafloxacin conformed to one compartment open model. After ig administration of 50 mg.kg-1 and 100 mg.kg-1 dose of clinafloxacin in six rats, mean Cmax and AUC values increased in proportion to dose. Mean T1/2 appeared to be independent of dose. Mean AUC was 65 +/- 6 and 27 +/- 4 micrograms.h.mL-1 respectively after i.v. and ig administration of 100 mg.kg-1 dose. The extent of bioavailability (F) of clinafloxacin was 42%. CONCLUSION: The results of the pharmacokinetic study of clinafloxacin showed that it exhibited first order kinetic characteristics and the bioavailability is low.

Animals↗
PubMed2001

[Alterations in the level of calcitonin gene related peptide and endothelin-1 in the cirrhotic rat heart].

OBJECTIVE: To investigate the role of calcitonin gene related peptide(CGRP) and endothelin-1 (ET-1) in cirrhotic cardiomyopathy (CCM). METHODS: We measured the level of CGRP and ET-1 in the samples of rat heart collected from 15 liver cirrhosis rats and 15 controls by using radio immunoassay. RESULTS: The data showed that the levels of CGRP (74.2130 +/- 10.3776 pg/mg protein) and ET-1 level (1.4780 +/- 0.9235 pg/mg protein) were significantly higher in the cirrhotic rat hearts than those in controls (P < 0.05). The increase of ET-1 in the cirrhotic rat hearts was closely associated with the severity of liver cirrhosis (P = 0.004); whereas no significant association was seen between the CGRP concentration and the severity of liver cirrhosis (P = 0.307). CONCLUSION: We infer that the increasing of CGRP level in the cirrhotic rat heart may be a protective or antagonistic reaction to ET-1 or other pathogenic factors for cardiac dysfunction. The disturbance of the balance between CGRP and ET-1 in the liver cirrhosis rat hearts may contribute to the pathologic process of CCM.

Animals↗
PubMed2001

[TGF beta 1 and ET-1 expression in the peripheral blood of patients with cirrhosis].

OBJECTIVE: The aims of this study were to determine 1. the variation of blood TGF beta 1 and ET-1 in patients with liver cirrhosis; 2. the relationship of the blood TGF beta 1 and ET-1 with Child degree of liver function and the severity of esophageal varices. METHODS: Peripheral blood samples were obtained from 72 patients and 24 normal controls. The blood levels of TGF beta 1 and ET-1 were measured by using a standard bioassay and the radioimmunoassay. RESULTS: TGF beta 1 level (11.77 +/- 1.32 ng/ml) and ET-1 level (78.37 +/- 17.54 pg/ml) were significantly higher in the patients than those in controls(P < 0.05). The increase of the ET-1 in the patients is closely associated with Child degree of liver function (r = 0.94) and the severity of esophageal varices(r = 0.87). TGF beta 1 concentration is not associated with Child degree of liver function (r = 0.11) and the severity of esophageal varices (r = 0.03). CONCLUSION: TGF beta 1 and ET-1 may play an important role in the pathophysiologic process of cirrhosis. ET-1 concentration may reflect portal hypertension development.

Adult↗
PubMed2001

[Correlation of JNK/SAPK activity and the production of ICAM-1 on renal mesangial cells in vitro].

OBJECTIVE: To observe the activity of c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) and assess the correlation between JNK/SAPK activity and ICAM-1 expression on mesangial cells in mesangial proliferative glomerulonephritis(MSPGN). METHODS: Seven patients with MSPGN and 6 controls were selected for this study. JNK/SAPK activity was detected by immunoprecipitation and western blotting; RT-PCR was used to detect ICAM-1 mRNA expression, and flow cytometry was used to analyze cell surface ICAM-1 expression. RESULTS: Either in spontaneous condition or under the stimulus of TNF alpha, the activity of JNK/SAPK on mesangial cells in vitro in MSPGN was higher than that of the controls(P < 0.05); the activity of JNK/SAPK in MSPGN was found to have a positive correlation with the levels of ICAM-1 mRNA and protein. The levels of ICAM-1 mRNA and protein were increased by TNF alpha stimulation while the levels ICAM-1 mRNA and protein were decreased by DMAP inhibition (P < 0.01). CONCLUSION: JNK/SAPK may have been aberrantly activated in MSPGN, which may involve in the overexpression of ICAM-1 in MSPGN.

Adaptor Proteins, Signal Transducing↗
PubMed2001

[Effects of transforming growth factor beta 1 on the expression of integrin beta 3 and the activity of focal adhesion kinase on human vascular endothelial cell].

OBJECTIVE: To observe the effects of transforming growth factors beta 1 (TGF beta 1) on the expression of integrin beta 3 and the activity of focal adhesion kinase (FAK). METHODS: This study was performed on cultured human endothelial cells (EC) by using cell-ELISA and immunoprecipitation-tyrosine kinase assay respectively. RESULTS: Under the stimulus of TGF beta 1, there a dose-dependent increase in the expression of integrin beta 3 chain in the surface of EC. And after the cultured EC were treated with 5 ng/ml or 10 ng/ml TGF beta 1 for 6 or 24 hours, the FAK activity in EC increased significantly as compared with the control group (P < 0.05). CONCLUSION: The expression of integrin beta 3 and the activity of FAK on EC were regulated by TGF beta 1, and this regulation may be important in cell adherence, angiogenesis, and in the pathophysiology of atherosclerosis.

Cells, Cultured↗
PubMed2001

[Effect of high glucose condition on the secretion of TGF beta by cultured macrovascular endothelial cells of the diabetic rat].

OBJECTIVE: This study was designed to examine the secretion of TGF-beta by cultured rat thoracic aortic endothelial cells of the diabetic rats under high gluocose condition. METHODS: First we created diabetic rat models, then the thoracic aortic endothelial cells of the diabetic rats were isolated and cultured in 10% FBS-RPMI 1640 media with various high glucose concentrations (12.5 mmol/L, 25 mmol/L or 50 mmol/L D-glucose), high glucose and TNF-alpha or high glucose and insulin for 48 hours, and the supernatant obtained from the cultured aortic endothelial cells was collected. The level of TGF-beta 1 in the supernatant was measured using a standard bioassay, which utilizes the TGF-beta 1 sensitive Mv1Lu (CLL-64) Mink lung epithelial cell line, and the production of endothelin (ET) in the supernatant was also assessed by RIA (radio immol/Lunoassay). RESULTS: Both total TGF-beta 1 (406 +/- 29 vs 189 +/- 23 pg/ml, P < 0.05) and active TGF-beta 1 (161 +/- 24 vs 39.5 +/- 8 pg/ml) secreted by the cultured aortic endothelial cells under high glucose condition (25 mmol/L) were significantly increased as compared with control. TNF-alpha could enhance the effect of high glucose on the secretion of TGF-beta 1, whereas insulin could inhibit it. With various high glucose concentrations, the levels of ET were increased. Also TNF-alpha enhanced it and insulin inhibited it. CONCLUSION: TGF-beta 1 may be involved in the development of diabetic macrovascular complication.

Animals↗
PubMed2001

[Inflammatory mediator in patients with obstructive jaundice and its effect on renal function].

OBJECTIVE: To investigate the effect of inflammatory transmitter on renal function in obstructive jaundice. METHODS: 15 patients with obstructive jaundice (OJ) as the experimental group and 15 non-joundiced patients as the control group were involved in this study. The plasma ET, LPS, TNF-alpha, IL-6, IL-8 and urine REP, TFR, ALB were measured in 15 patients with OJ before and 1, 4, 7 days after surgery and in 15 patients without jaundice as controls. RESULTS: The levels of plasma ET, LPS, TNF-alpha, IL-6, IL-8 and urine RBP, TFR, ALB increased significantly at multiple time points as compared with those in the non-OJ patients (P < 0.05), and the changes of plasma ET, LPS, TNF-alpha, IL-6, IL-8 are the same as those of urine RBP, TFR, ALB. CONCLUSION: These data suggest that there is interaction between ET, LPS, TNF-alpha, IL-6, IL-8 and the damage to renal function with OJ after surgery.

Adult↗
PubMed2001

[Study on mutations in the connexin 26 gene among Chinese with nonsyndromic hearing loss].

OBJECTIVE: To study the relation between nonsyndromic hearing loss in Chinese and mutations in connexin 26 (Cx 26) gene and to explore the pathogenic mechanism. METHODS: One hundred and thirty-eight individuals from thirty-five pedigrees with nonsyndromic hearing loss, 99 children with sporadic nonsyndromic hearing loss and 100 normal adults as control were collected in present studies. The Cx 26 coding sequence was screened by single strand conformational polymorphism (SSCP) and analyzed by direct sequencing when SSCP shifts were observed. RESULTS: Five SSCP shifts in 2 pedigrees were observed. Homozygous deletion C at position 233-235 of Cx 26 cDNA, which resulted in frameshift mutation, was found in 2 pedigrees with nonsyndromic hearing loss. CONCLUSION: The hot-spot mutations of Cx 26 gene in Chinese with nonsyndromic hearing loss may be different from other ethnic groups. The 233-235 delC homozygous mutation of Cx 26 cDNA can result in autosomal recessive nonsyndromic hearing loss in Chinese population.

Adult↗
PubMed2001

[Maxillofacial vascular malformation associated with abnormal communication between external carotid and cranial arteries].

OBJECTIVE: To introduce the clinical characteristics of maxillofacial vascular malformation with abnormal communication between external carotid and cranial arteries. METHODS: One hundred and twenty patients with maxillofacial vascular malformations had been studied by arteriography of internal and external carotid, and vertebral arteries before embolization of tumor supplying artery. Cases found to have communications between extra- and intra-cranial arteries were analyzed. RESULTS: Fourteen patients (11.67%, 14/120) were found to have abnormal communications between external carotid and cranial arteries. Among them, 11 patients demonstrated communications between occipital and vertebral arteries, 1 patient showed ascending pharyngeal artery and vertebral artery communication, and 2 patients showed maxillary artery-ophthalmic artery communication. CONCLUSION: Embolization of tumor supplying artery is a safe and practical method for the treatment of maxillofacial vascular malformation when done under digital subtraction angiography and superselective catheterization to avoid the abnormal communicant branches.

Adolescent↗
PubMed2001

Urotensin II receptor in the rat airway smooth muscle and its effect on the rat airway smooth muscle cells proliferation.

OBJECTIVE: To investigate the characteristics of urotensin II (U-II) receptor in the rat airway smooth muscle and the effect and signal transduction pathway of U-II on the proliferation of airway smooth muscle cells. METHODS: Using 125I-UII binding assay to measure the Bmax and Kd of U-II receptor. Using the 3H-TdR incorporation to determine the effect of U-II on the proliferation of airway smooth muscle cells and its signal transduction pathway. Using Fura-2/AM to measure the effect of U-1I on the cytosolic free calcium concentration. RESULTS: 1. 125I-UII binding increased with the time and reached saturation at 45 min. The B(max0 was (11.36 +/- 0.37)fmol/mg pr and Kd was (4.46 +/- 0.61) nmol/L. 2. U-II increased 3H-TdR incorporation of the airway smooth muscle cells in a dose-dependent manner. 3. H7, PD98059 and nicardipine, inhibitors of PKC, MAPK, calcium channel, respectively, significantly inhibited U-II-stimulated 3H-TdR incorporation of airway smooth muscle cells. W7, inhibitor of CaM-PK, had no effect. 4. Cyclosporin A, inhibitor of CaN, inhibited 3H-TdR incorporation of the airway smooth muscle cells induced by U-II in a dose-dependent manner. 5. U-II promoted cytosolic free calcium concentration increase by 18%. CONCLUSIONS: 1. There was U-II receptor in the rat airway smooth muscle. 2. The effect of U-II-stimulated 3H-TdR incorporation of airway smooth muscle cells was mediated by such signal transduction pathway as Ca2+, PKC, MAPK and CaN, etc.

Animals↗
PubMed2001

[Study of Raman-PL spectra for GaAs layer on Si substrate in hot wall epitaxy].

The quality of GaAs layer on the Si substrate under different growth conditions with HWE technology was studied by Raman and PL spectra. The results show that the ratio of peak value to area for the TO peak at 265 cm-1 increased gradually with the improvement of the GaAs crystallinity quality for the GaAs layer at 300 K. The FWHM of Raman spectra of TO peak at 265 cm-1 is narrow, and the Raman shift is 2 cm-1. In the PL spectra, the FWHM at 900 nm is narrow. Then the results show GaAs layer is highly structural quality. But if we can not measure the PL peak at 900 nm, or the FWHM of Raman spectra of TO peak at 265 cm-1 is not narrow, the GaAs layer is not crystallinity. Therefore, we can estimate the layer quality by Raman and PL spectra.

Arsenicals↗
PubMed2001

[Investigation on the excited state dynamics properties of hemicyanine molecules].

In this paper, the excited state dynamics properties of hemicynine were investigated by using time-resolved fluorescence and 3D fluorescence spectra techniques. The interaction of hemicyanine molecules caused formation of H-aggregates and a blue shift of the 3D fluorescence spectra in interleaving hemicyanine/arachidic acid multilayers. The peak of fluorescence was a red shift along with the time decay. The lifetime of the LB fluorescence was much shorter and the difference of beginning luminescence was less than that of the hemicyanine solution due to the stronger intermolecule interactions in the aggregates.

English Abstract↗
PubMed2001

[Uncommon fluorescent properties of nano-structured terbium (III)-phthalic acid complex in polyvinylpyrrolidone].

Nano-sized terbium(III)-phthalic acid complex was prepared in polyvinylpyrrolidone. It's fluorescent spectrum has been investigated, compared to that of common terbium(III)-phthalic acid complex and terbium(III)-polyvinylpyrrolidone complex. The results show that fluorescent characterizations of Nano-sized terbium(III)-phthalic acid complex is obviously different from that of common terbium(III)-phthalic acid complex and terbium(III)-polyvinylpyrrolidone. The relative intensity and half-height width of main emission peaks are obviously varied, two splitting peaks are displayed.

Chelating Agents↗
PubMed2001

[On the characteristics of velocity modulation laser spectroscopy].

The technical properties of velocity modulation laser spectroscopy were investigated using the spectrum of A2 pi u-X2 sigma g+ (2-0) band of Meinel system of N2+. The dependence of spectral intensity on discharge current, the pressure of the gas mixture and the pump velocity of the vacuum pump were studied. Making uses of the results of these studies, the sensitivity and resolution of the spectrometer are improved by above 3 times, and economized the experimental expenses can be reduced to as 3/4 time as normal, which confirms that the results of this paper is of considerable uses.

Lasers↗
PubMed2001

[Assignments of FIR-LMR spectra of CF X 2Pi (nu = 1) and MIR-LMR spectra of NO X 2Pi (nu = 1<--0)].

According to the theories of Zeeman effect and the principle of laser magnetic resonance (LMR), a method and model for the analysis of the laser magnetic resonance spectra were developed and successfully employed to assign the FIR-LMR spectra of CF X2 Pi (nu = 1) and the MIR-LMR spectra of NO X 2Pi (nu = 1<--0). This work provided an efficient and accurate approach for primary analysis of the LMR spectra of novel radicals.

English Abstract↗
PubMed2001

[An epidemiological study of spongiform leucoencephalopathy among heorin abusers].

OBJECTIVE: To understand the distribution and related risk factors of heroin spongiform leucoencephalopathy among drug users in coastland of Guangdong Province. METHODS: A cross-sectional study was conducted in four thousand four hundred and twenty eight drug users from eighteen detoxification organizations in six cities on coastland of Guangdong, using clustered random sampling methods. The six cities are Chaoyang (714), Heyuan (462), Shantou (572), Huidong (1286), Guangzhou (871) and Zhanjiang (523) and heroin abuse was considered serious in these cities. Questionnaire was used to collect the data on sex (man 3632, 82 percent; woman 795, 18 percent), age (minimum 15y, maximum 54y), duration of using heroin (minimum 1 month, maximum 150 months), daily dosage (minimum 0.02 g, maximum 6.0 g) and manner of using heroin. In addition, the neurological examination was taken in all of them and cerebral MRI was carried out in those with signs of cerebellar ataxia. RESULTS: Results showed that the total incidence of heroin spongiform leucoencephalopathy in six cities is 3.16 per thousand. Poisson regression analysis showed that the incidence was related to residential areas. In comparison with other cities, there are higher incidences in Chaoyang and Heyuan. Our investigation also showed that all the patients with this disease used heroin by inhaling the pyrolysate. The incidence of heroin spongiform leucoencephalopathy was unrelated to the daily inhaling amount of heroin and the duration of inhaling heroin. No differences could be observed between the groups of different age and sex. CONCLUSIONS: Spongiform leucoencephalopathy after inhalation of heroin is a rare complication and has never been reported in mainland of China before. The lesions are symmetrical and spongiform, but not necrotic and the cerebellum is invariably involved--a feature consistent with the clinical presentation that begins with ataxia. Cerebral CT showed symmetrical non-enhancing hypodense areas in both cerebellar hemispheres. Cerebral MRI showed the corresponding areas with decreased signal intensity on T1 weighted images and increased signal intensity on T2 weighted images. There was no contrast enhancement. When it occurs, several cases are affected as a small epidemic. It is suggested that the aetiology is related to the heroin batch and could perhaps be a toxic effect of a substance which came from heroin pyrolysis.

Administration, Inhalation↗