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R Liu

Publications and source records attributed to R Liu.

At least 163 records · Page 9Linked to original sources
PubMed1999

Associations among serum lipoprotein(a) levels, apolipoprotein(a) phenotypes, and myocardial infarction in patients with extremely low and high levels of serum lipoprotein(a).

A high serum lipoprotein(a) [Lp(a)] level, which is genetically determined by apolipoprotein(a) [apo(a)] size polymorphism, is an independent risk factor for coronary atherosclerosis. However, the associations among Lp(a) levels, apo(a) phenotypes, and myocardial infarction (MI) have not been studied. Patients with MI (cases, n = 101, M/F: 86/15, age: 62+/-10y) and control subjects (n = 92, M/F: 53/39, age: 58+/-14y) were classified into quintile groups (Groups I to V) according to Lp(a) levels. Apo(a) isoform phenotyping was performed by a sensitive, high-resolution technique using sodium dodecyl sulfate-agarose/gradient polyacrylamide gel electrophoresis (3-6%), which identified 26 different apo(a) phenotypes, including a null type. Groups with higher Lp(a) levels (Groups II, III, and V) had higher percentages of MI patients than that with the lowest Lp(a) levels (Group I) (54%, 56%, or 75% vs. 32%, p<0.05). Groups with different Lp(a) levels had different frequency distributions of apo(a) isoprotein phenotypes: Groups II, III, IV, and V, which had increasing Lp(a) levels, had increasingly higher percentages of smaller isoforms (A1-A4, A5-A9) and decreasingly lower percentages of large isoforms (A10-A20, A21-A25) compared to Group I. An apparent inverse relationship existed between Lp(a) and the apo(a) phenotype. Subjects with the highest Lp(a) levels (Group V) had significantly (p<0.05) higher serum levels of total cholesterol, apo B, and Lp(a). Patients with MI and the controls had different distributions of apo(a) phenotypes: i.e., more small isoforms and more large size isoforms, respectively (A1-A4/A5-A9/A10-A20/A21-A25: 35.7%/27.7%/20.8%/15.8% and 22.8%/23.9%/29.4%/23.9%, respectively). Lp(a) (parameter estimate +/- standard error: 0.70+/-0.20, Wald chi2 = 12.4, p = 0.0004), apo(a) phenotype (-0.43+/-0.15, Wald chi2 = 8.17, p = 0.004), High-density lipoprotein-cholesterol, apo A-I, and apo B were significantly associated with MI after adjusting for age, gender, and conventional risk factors, as assessed by a univariate logistic regression analysis. The association between Lp(a) and MI was independent of the apo(a) phenotype, but the association between the apo(a) phenotype and MI was not independent of Lp(a), as assessed by a multivariate logistic regression analysis. This association was not influenced by other MI- or Lp(a)-related lipid variables. These results suggest that apo(a) phenotype contributes to, but does not completely explain, the increased Lp(a) levels in MI. A stepwise logistic regression analysis with and without Lp(a) in the model identified Lp(a) and the apo(a) phenotype as significant predictors for MI, respectively.

Apolipoproteins A↗
PubMed1999

Development of muscarinic analgesics derived from epibatidine: role of the M4 receptor subtype.

Epibatidine, a neurotoxin isolated from the skin of Epipedobates tricolor, is an efficacious antinociceptive agent with a potency 200 times that of morphine. The toxicity of epibatidine, because of its nonspecificity for both peripheral and central nicotinic receptors, precludes its development as an analgesic. During the synthesis of epibatidine analogs we developed potent antinociceptive agents, typified by CMI-936 and CMI-1145, whose antinociception, unlike that of epibatidine, is mediated via muscarinic receptors. Subsequently, we used specific muscarinic toxins and antagonists to delineate the muscarinic receptor subtype involved in the antinociception evoked by these agents. Thus, the antinociception produced by CMI-936 and CMI-1145 is inhibited substantially by 1) intrathecal injection of the specific muscarinic M4 toxin, muscarinic toxin-3; 2) intrathecally administered pertussis toxin, which inhibits the G proteins coupled to M2 and M4 receptors; and 3) s.c. injection of the M2/M4 muscarinic antagonist himbacine. These results demonstrate that the antinociception elicited by these epibatidine analogs is mediated via muscarinic M4 receptors located in the spinal cord. Compounds that specifically target the M4 receptor therefore may be of substantial value as alternative analgesics to the opiates.

Alkaloids↗
PubMed1999

Isoproterenol, forskolin, and cAMP-induced nitric oxide production in pig ciliary processes.

PURPOSE: To investigate whether isoproterenol and forskolin, two adenylylcyclase activators, or 8-bromo-cAMP, an adenosine 3',5'-cyclic monophosphate (cAMP) analog, increase nitric oxide (NO) production in isolated porcine ciliary processes. METHODS: Nitrite (an NO metabolite) was measured (Griess reaction) before and 2 hours after exposure to 0.1 to 100 microM isoproterenol (a beta-adrenoreceptor agonist), 0.01 to 100 microM forskolin, or 0.1 to 1000 microM 8-bromo-cAMP. Some experiments were conducted in the presence of 0.5 mM N(G)-nitro-L-arginine methyl ester (L-NAME; a nitric oxide synthase [NOS] inhibitor), 10 microM propranolol (a beta-adrenoreceptor antagonist), or 1 microM KT 5720 (a cAMP-dependent protein kinase inhibitor). cAMP production was also measured (by immunoassay). RESULTS: Nitrite production was increased by isoproterenol (maximum, 10 microM: 164%; P < 0.001), forskolin (maximum, 10 microM: 254%; P < 0.001), and 8-bromo-cAMP (maximum, 100 microM: 184%; P < 0.001), an effect prevented by L-NAME (P < 0.05-0.001). Propranolol inhibited only isoproterenol-induced (10 microM) nitrite production (P < 0.05), whereas KT 5720 (P < 0.05) inhibited isoproterenol- (10 microM) and 8-bromo-cAMP-induced (10 microM) nitrite production. Furthermore, cAMP production evoked by isoproterenol (10 microM, P < 0.05) but not by forskolin (10 microM, P < 0.001) was inhibited by propranolol (P < 0.05). CONCLUSIONS: In isolated porcine ciliary processes, drugs activating adenylylcyclase or mimicking cAMP increase the production of NO by a mechanism that appears to involve both a cAMP-dependent protein kinase and NOS.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1999

[Expression patterns of platelet membrane glycoprotein in healthy adults].

OBJECTIVE: To study the expression patterns of 6 kinds of platelet membrane glycoprotein(GP) in resting and activated platelets of healthy adults. METHODS: The molecule numbers of platelet GPIIIa, IIb/IIIa, Ib, IX, V and P-selectin on resting platelets or platelets activated by thrombin receptor activating peptide (TRAP) in 60 healthy adults (male/female = 1/1) were detected by flow cytometry. RESULTS: The expression of GPIIb/IIIa and GPIIIa seemed to decrease with the increase of age in the resting and activated platelets of males. The coefficients of correlation(r) in resting platelets were -0.409 and -0.534 (P < 0.05), respectively; whereas this phenomenon were not found in females. The expression of GPIb was reduced while the expressions of GPIIb/IIIa, IIIa, P-selectin increased after the platelets were activated by TRAP. There was a negative relationship between resting and activated platelets in the expression of P-selectin. The molecule number of GPIb on the surface of resting platelet was about 30,000, the ratio of GPIb to GPV was 3:1. CONCLUSION: It seems that there exists some difference with age and sex in the expression of platelet membrane glycoproteins in healthy persons.

Adult↗
PubMed1999

[The elastase activity in gingival crevicular fluid from rapidly progressive periodontitis].

OBJECTIVE: It is now generally accepted that polymorphonuclear neutrophil (PMN) chemotactic defect increases the patient's susceptibility to early-onset periodontitis. However, some reports including ours have failed to show defective PMN chemotaxis in rapidly progressive periodontitis(RPP) patients. The purpose of the study was to survey the role of PMN in the progression of RPP. METHODS: The elastase activity in gingival crevicular fluid from 22 RPP patients and 11 healthy controls were studied. For the control group and 12 RPP patients, 30 s GCF and clinical data were obtained at the first visit. For other 10 RPP patients, 30 s GCF and clinical data were collected prior to treatment and 4 weeks after scaling and root-planing. The elastase activity was measured with a low molecular weight substrate (L-Pyroglutamyl-L-prolyl-L-valine-p-nitroaniline, S2484) specific for granulocyte elastase. RESULTS: The pre-treatment elastase activity was much higher (0.63 +/- 0.38, Abs/site) in RPP patients than that in control subjects (0.07 +/- 0.05, Abs/site). The elastase activity was positively correlated with GCF volume, probing depth, attachment loss and gingival bleeding. Scaling and root-planing resulted in decrease of both clinical data and elastase activity. CONCLUSION: These results suggested that PMN with the increased accumulation or the increased release of lysosomal enzymes may play a role in the pathogenesis of RPP.

Adult↗
PubMed1999

[A study on the reserve capacity of endothelial tissue plasminogen activator in patients with acute coronary syndrome].

OBJECTIVE: To study the changes of the endothelial tissue plasminogen activator (tPA) reserve capacity in patients with acute coronary syndromes (ACS). METHODS: Veinous blood was sampled for determination of markers of the fibrinolytic system and hypercoagulability at admission and on the 10th day in patients with acute coronary syndrome (ACS), including acute myocardial infarction (AMI) in 15 and unstable angina pectoris (UAP) in 20. An occlusion test to determine the maximal endothelial tPA release was performed in order to evaluate the endothelial tPA reserve capacity. 20 patients with stable angina pectoris (SAP) and 12 normal subjects served as control. RESULTS: Patients with ACS had higher levels of tPA mass concentration, PAI-1 activity, D-dimers mass concentration and TAT mass concentration at admission and on the 10th day as compared with those in SAP and normal subjects. Maximal endothelial tPA release was initially reduced to (2.2 +/- 0.8) microg/L (P < 0.01, vs patients with SAP), but the levels recovered on the 10th day of follow-up to (4.5 +/- 1.2) microg/L (P > 0.05, vs patients with SAP). CONCLUSION: Endothelial tPA reserve capacity is reduced only during the acute phase and becomes normalized during follow-up. The alterations of plasma markers of systemic fibrinolysis persist longer in patients with ACS. The results demonstrated that the intravascular thrombus formation may relate more to the disturbance of endothelial fibrinolysis than to markers of the systemic fibrinolytic system. It is very important to correct the disturbances of endothelial fibrinolysis during the acute phase of ACS.

Acute Disease↗
PubMed1999

[Inhibitory effect of conjugated linoleic acid on human gastric carcinoma cell line].

The effects of conjugated linoleic acid (CLA) on human gastric carcinoma cell line (SGC-7901) were studied in cell culture. The four levels of CLA in medium were designed as 25, 50, 100 and 200 mumol/L, and the dissolvent control being ethane. The result displayed that CLA could inhibit the cell proliferation, cellular mitosis, cell clone formation and DNA synthesis and induce cellular differentiation of SGC-7901 cells.

Adenocarcinoma↗
PubMed1999

[Clinical and pathological analysis in 327 cases with renal biopsy].

The renal biopsy results of 372 cases are summarized in this article. Definite pathological diagnoses were made in 354 cases, among which most cases were of mesengioproliferative glomerulonephritis type (27.1%), followed by glomerulopathy type with minimal change(12.4%). The association between clinical manifestation and pathological change was discussed. The data indicate that renal biopsy plays pivotal role in confirming the clinical diagnosis and guiding treatment.

Adolescent↗
PubMed1999

[Perhydrit and sodium bicarbonate improve maternal gases and acid-base status during the second stage of labor].

Perhydrit and sodium bicarbonate were administered to 99 women during the second stage of labor. Gas analysis was done twice at the beginning and the end of the second stage. The results showed that 33 women received both perhydrit and sodium bicarbonate(Group I) had significantly higher pH, BE, pO2, and O2sat at the end of the second stage than those of 30 controls (Group III) (P < 0.05 and < 0.01). And 33 women received only sodium bicarbonate(Group II) showed merely higher pH and BE than those of Group III. The difference was significant(P < 0.05 and < 0.01), while PO2 and O2sat had no statistical difference between Group II and Group III. By comparing the values, we found that pH, PO2 and O2sat were much higher at the end of the second stage in Group I and Group II than those at the beginning of the second stage(P < 0.05 and < 0.01). No statistical difference of BE had been found between both groups. In contrary, BE, pH, PO2 and O2sat declined at the end of the second stage in Group III (P < 0.02 and < 0.01). There were no significant differences of PCO2 among the three groups. It is suggested that the administration of perhydrit and sodium bicarbonate may effectively improve the tendency of maternal metabolic acidosis and tissue oxygen debt caused by consumption and uterine contractions during the second stage, subsequently improve maternal gases and acid-base status.

Acid-Base Imbalance↗
PubMed1999

[Effect of benazepril on renal interstitial inflammatory cell infiltration in rats with unilateral ureteral obstruction].

Effect of benazepril on renal interstitial inflammatory cell infiltration was observed in rats with unilateral ureteral obstruction(UUO). The results showed that the relative volume of interstitium and number of infiltrating inflammatory cell on the fifth day were significantly less in rats with benazepril than the control group, but the difference between two groups lose significance on the tenth day. These data indicate that benazepril can ameliorate early phase of renal interstitial inflammation in UUO.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

[Purification and characterization of alkaline xylanases from Pseudomonas G6-2].

Pseudomonas G6-2 produced two extracellular xylanases, named XynA and XynB. The enzymes were purified by ammonium sulfate fractionation, Sephadex G-100, DEAE-Sephadex, CM-Sephadex and Bio-gel P-10 chromatographies. Both enzymes were indicated to be endoxylanases, which produced oligomers of xylose from xylan and did not hydrolyze it to xylose. They had same temperature optimum(50 degrees C) and different pH optimum(pH 7.0-9.8 for XynA and pH 7.0-8.0 for XynB). At pH 7.6 and 65 degrees C, XynA and XynB possessed the half life of 6 min and 140 min, respectively. Their activities were strongly inhibited by Cu2+, Fe3+, Pb2+, Zn2+ and Hg2+. The results of chemical modification indicated that tryptophan and carboxy group were related to active center.

Endo-1,4-beta Xylanases↗
PubMed1999

[Changes in chloroquine resistance of Plasmodium falciparum in Hainan province].

AIM: To observe the variation in resistance of Plasmodium falciparum after the cessation of chloroquine medication. METHODS: WHO standard in vitro microtest and in vivo test were used. RESULTS: In vitro test showed that the rate of chloroquine-resistant P. falciparum dropped from 97.9% in 1981 to 26.7% in 1997 (P < 0.001). The mean concentration of chloroquine for complete inhibition of schizont formation declined from 10.46 +/- 7.14 pmol/ul blood in 1981 to 1.63 +/- 1.47 pmol/microliter blood in 1997(P < 0.001). In vivo test showed that the rate of chloroquine-resistant P. falciparum decreased from 84.2% in 1981 to 18.4% in 1997(P < 0.001). The proportion of R III cases to the total resistant cases dropped from 53.1% in 1981 to 14.3% in 1997. CONCLUSION: A tendency of progressive decline of resistance of the parasite was revealed after the cessation of chloroquine medication.

Adolescent↗
PubMed1999

[Changes in transforming growth factor beta 1 mRNA and its clinical value in patients with schistosomal liver fibrosis].

AIM: To explore the changes in TGF-beta 1 mRNA in patients with schistosomal liver fibrosis. METHODS: Reverse-transcription polymerase chain reaction and dot blot analysis were used to determine the level of TGF-beta 1 mRNA in PBMC. The serum levels of hyaluronic acid, type IV collagen, laminine and procollagen III peptide were also measured simultaneously. RESULTS: The mean level (m +/- s) of PBMC TGF-beta 1 mRNA was significantly higher in late-stage schistosomiasis group (LSS) (1.26 +/- 0.14), liver cirrhosis group (LC) (2.05 +/- 0.81) and hepatocellular carcinoma group (HCC) than that in control group (0.62 +/- 0.40) (P < 0.05). PBMC TGF-beta 1 mRNA level was higher in LC and HCC than that in LSS (P < 0.05). No significant difference was found in TGF-beta 1 mRNA between PBMC and liver tissue in patients with HCC. All patients with increased fibrogenic activity (i.e., abnormal levels of serum HA, Col-IV and LN) had increased levels of TGF-beta 1 mRNA. CONCLUSION: The level of TGF-beta 1 mRNA is correlated with the fibrotic activity of liver, the increasement of TGF-beta 1 mRNA in schistosomiasis patients after praziquantel treatment might induce liver fibrosis.

Adult↗
PubMed1999

Sequence analysis of the MSP 1 gene of Plasmodium falciparum isolates from Hainan, China.

AIM: To obtain the complete sequence and analyze the diversity of the MSP 1 molecule from the Chinese isolates of Plasmodium falciparum. METHODS: Genomic DNA was prepared directly from blood samples spotted on filter papers from 2 malaria patients from Baoting County, Hainan Province. PCR amplification of the target gene was carried out using 5 pairs of oligonucleotides specific for the MSP 1 gene. Direct sequencing of the target gene fragments was performed using ABI PRISM Dye Terminator Cycle Sequencing Ready Reaction Kit (Perkin Elmer) in a automatic ABI PRISM 310 Genetic Analyzer. RESULTS: For the first time, two complete sequences of the MSP1 gene from two Chinese isolates of Plasmodium falciparum were obtained. A comparison with the previously reported sequences identified them as members of the MAD20 allelic family. The deduced amino acid sequences of the MSP1 from this two Chinese isolates were identical with each other except for Blocks 2, 4 and 8. CONCLUSION: The sequences of the MSP 1 from two Chinese isolates of P. falciparum belong to the MAD20 allelic family. Minor variations through the whole sequences exist compared with the MAD20 sequence. The results provide the first evidence of the diversity of the MSP 1 molecule from Chinese isolates of Plasmodium falciparum.

Amino Acid Sequence↗
PubMed1999

[Surgical reconstruction of laryngeal and tracheal stenosis].

OBJECTIVE: Reconstruction of laryngotracheal stenosis. METHOD: According to the pathologic condition of the larynx and trachea, various surgical procedures were designed for the treatment of laryngotracheal stenosis. These techniques included endoscopic management, laser therapy and laryngotrachoetomy with autogenous tissue and stent. RESULT: Among 36 patients, 32 were decannulated. The success rate was 88.8%. CONCLUSION: In order to improve the curation effects of laryngjotrachal stenosis, the choice of surgical procedure must be individualized to the pathologic condition of larynx and trachea, as well as the experience of the surgeon. Learning previous successful experience is also very important for a good result.

Adolescent↗
PubMed1999

[A preliminary study of two Chinese herbs protective tablets on some Chinese traditional medicines].

The protective action of 2 tablets of Chinese herb to 5 Chinese traditional medicines against harm of insects and mildews was tested. It was found that 2 tablets have a obvious effects of insect-repellency and mouthproof in the test with Homalomena occulta and Prunus armeniaca, the bore in the medicinal materials was decreased 94.95% and 95.55% respectively than that of check. The tablets have some effects of mildewproof in the test with Tussilago farfara.

Alisma↗
PubMed1999

Increased hydroxyl radical production and apoptosis in PC12 neuron cells expressing the gain-of-function mutant G93A SOD1 gene.

Mutations of the SOD1 gene (formerly known as Cu,Zn-SOD) are frequently associated with the familial form of amyotrophic lateral sclerosis (ALS). The G93A mutation of SOD1 with substitution of Gly to Ala at residue 93 results in gain of a peroxidative function. Here we report that transfection of PC12 neuron precursor cells with the G93A mutation of SOD1 results in increased production of hydroxyl radicals (*OH) and an enhanced rate of cell death by apoptosis. Notably, PC12 cells transfected with the H63C/G93A mutant of SOD1 with a mutation in the catalytic site that converts histidine at position 63 to cysteine showed a dramatically reduced production of *OH and rate of death by apoptosis. Thus the gain of function of the mutant G93A SOD1 can be reduced by an active site mutation. These results provide additional genetic evidence for the hypothesis that the increased *OH production and induced cytotoxicity in neuron cells expressing the mutant G93A SOD1 results from the gain of peroxidative function by the enzyme's catalytic site.

Animals↗