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Biomedical subjects

L Li

Publications and source records attributed to L Li.

At least 1,153 records · Page 64Linked to original sources
PubMed1998

[PCR-based analysis of the D1S80 locus and its application in paternity test].

Allelic data for the D1S80 locus was obtained by using the PCR and subsequent analysis with high-resolution horizontal PAGE technique. In a sample of 184 unrelated Chinese, the D1S80 locus had 75 phenotypes and 20 allelic. The distribution of genotype was in agreement with expected values according to the Hardy-Weinberg equilibrium. Analysis of the D1S80 locus by the PCR has been successfully applied in 150 cases of questioned paternity.

Alleles↗
PubMed1998

[Protective effects of schisanhenol against oxygen free radical induced injury of rat cerebral mitochondria and synaptosomes].

The cerebral tissue injury induced by ischemia and reperfusion or trauma has been considered to be due to over production of oxygen free radicals (OFRs). The aim of this study was to evaluate the effects of schisanhenol (Sal) on Fe(2+)-cysteine (Cys) induced injury of rat cerebral mitochondria and synaptosomes in vitro. Incubation of cerebral mitochondria or synaptosomes with Fe(2+)-Cys at 37 degrees C resulted in an increase of malondialdehyde (MDA) formation and decrease of ATPase activity. Sal(10(-4) mol.L-1) completely inhibited Fe(2+)-Cys induced increase of MDA formation of mitochondria and synaptosomes as well as the loss of ATPase activity of mitochondria. The swelling of mitochondria and reduction of membrane fluidity of mitochondria and synaptosomes induced by Fe(2+)-Cys were also prevented by Sal. Sal(10(-5) mol.L-1) was shown to significantly inhibit the decrease of synaptosomal GSH content induced by H2O2. The electron micrographs also showed that Sal markedly reduced the pathological damage of mitochondria and synaptosomes induced by Fe(2+)-Cys. The results suggest that Sal has protective action against Fe(2+)-Cys induced injury of rat cerebral mitochondria and synaptosomes.

Adenosine Triphosphatases↗
PubMed1998

[Changes of CYP2E1 activity in diabetic rat model].

Diabetic rat model was induced by alloxan. To evaluate CYP2E1 activity indirectly, the activities of aniline dehydroxylase and other drug metabolic enzymes were measured. The pharmacokinetic profile of chlorzoxazone(CZX), a drug probe for CYP2E1, was obtained after a single oral dose of 50 mg.kg-1. The results indicated that diabetes increased aniline dehydroxylase activity by 53%. The Cmax and AUC of chlorzoxazone in diabetic rats were reduced 37% and 34%, respectively. The Tpeak of 6-hydroxychlorzoxazone in diabetic rats was shortened apparently. The hydroxylation index described by the AUC ratio of 6-hydroxychlorzoxazone to chlorzoxazone or the ratio of concentration of 6-hydroxychlorzoxazone to chlorzoxazone, which indicated the ability of hydroxylation, was increased in diabetes. In conclusion, diabetes can induce CYP2E1 activity, suggesting that diabetic patients should be cautious when taking some therapeutic drugs which metabolized by CYP2E1.

Aniline Hydroxylase↗
PubMed1998

[Synthesis and antiinflammatory activity of 2-(E)-(4-hydroxy-3-methoxybenzylidene)-5-(N-substituted aminomethyl) cyclopentanones].

In search for new antiinflammatory agents, a series of 2-(E)-(4-hydroxy-3-methoxybenzylidene)-5-(N-substituted aminomethyl) cyclopentanones was synthesized via Stork reaction, Mannich reaction and amine exchange reaction. All of the fifteen target compounds were characterized by spectral analysis and elemental analysis. Preliminary pharmacological tests showed that several target compounds exerted appreciable effect on xylene-induced ear edema in mice and that alteration of the substituents of anilines showed significant influence on antiinflammatory potency.

Animals↗
PubMed1998

[The determination of ligustilide in Ligusticum chuanxiong Hort. by supercritical fluid extraction].

In this study, a systematic method was used to optimize the supercritical fluid extraction (SFE) of ligustilide in Ligusticum chuanxiong Hort. Overall five variables (pressure, temperature, static extracting time, modifier concentration and CO2 dynamic extracting volume) were considered. To reduce the loss of volatile substance, a solid-liquid trap was developed for SFE collection. Comparisons were made on the solvent trap for SFE. The extracts were analyzed by high performance liquid chromatography (HPLC) with ultraviolet absorbance detection. The recoveries of 99.34% (RSD 1.70%) and 92.11% (RSD 5.72%) were achieved for solid-liquid trap and solvent trap, respectively. SFE conditions: temperature 40 degrees C, pressure 27.6 MPa, static extraction 3 min, dynamic extraction 7 ml and 0.1 ml CHCl3 as modifier. HPLC conditions: The HPLC column (3.9 mm x 150 mm) was packed with Nova-Pak C18(4 microns). Naphthalene was used as internal standard. The mobile phase was methanol--10% isopropyl alcohol solution (53:47 v/v). The detection wavelength was 280 nm and the flow rate was 0.8 ml.min-1.

4-Butyrolactone↗
PubMed1998

[Determination of chlorzoxazone and its metabolite 6-hydroxychlorzoxazone in plasma by HPLC and their pharmacokinetics].

A rapid and sensitive HPLC assay was developed for the quantitation of chlorzoxazone and its metabolite 6-hydroxychlorzoxazone in plasma. These compounds, as well as internal standard 5-fluorobenzoxazolone, were extracted with ethyl acetate, then were analyzed on Alltima C18 column with a mobile phase of acetonitrile-0.5% acetic acid, and detected at 287 nm. The retention times of 6-hydroxychlorzoxazone, internal standard and chlorzoxazone were 6.12 min, 10.47 min and 18.65 min, respectively. The linearity of the method was tested in the concentration range 0.5-20 micrograms.ml-1, and the limits of detection of 6-hydroxychlorzoxazone and chlorzoxazone were found to be 0.2 and 0.5 microgram.ml-1, respectively. Inter-day and intra-day relative standard deviations (RSD) were below 8% and 11%. The recoveries of these two compounds were between 82.80%-100.76%. The pharmacokinetic profile of chlorzoxazone in human following an oral dose of 400 mg was studied. Both absorption and elimination of chlorzoxazone were found to be rapid in human. There seemed to be an obvious interindividual difference and perhaps an interracial difference as well, when compared with other races.

Adult↗
PubMed1998

[Isolation and structure of 6'-O-caffeylerigeroside from Erigeron multiradiatus].

The plant, Erigeron multiradiatus (Wall.) Benth(Family: Compositae), is a perennial herb distributed abundantly in the mountainous area of the southwestern part in China. It is used in folk medicine for the treatment of common cold, panting cough, rheumatic, enteritis and toothache. In this paper, we report a new glycoside named as 6'-O-caffeylerigeroside isolated from Erigeron Multiradiatus (Family: Compositae) together with four known compounds. The known compounds were identified as pyromeconic acid(I), scopoletin(II), 4-hydroxybenzoic acid(III) and vanillic acid(IV). The structure of 6'-O-caffeylerigeroside was elucidated as gamma-pyrone-3-O-[6"-(3',4'-dihydroxy-cinnamoyl)]-beta-D-glucoside(V) on the basis of chemical evidence and spectral data.

Asteraceae↗
PubMed1998

[Protective effects of schisanhenol, salvianolic acid A and SY-L on oxidative stress induced injuries of cerebral cells and their mechanisms].

Oxidative stress may play an important role in neuronal degenerative diseases such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. These disorders make the elderly not being able to live normally and move freely. So it is necessary to find effective antioxidants to prevent or cure the aged persons from diseases related to neuronal degeneration. Schisanhenol (Sal) and salvianolic acid A (Sal A) are known antioxidants which were isolated from Chinese herbs respectively. SY-L is a totally synthetic new compound. The results showed that Sal, Sal A and SY-L significantly protect cerebral cells from the injuries induced by oxidative stress.

Alzheimer Disease↗
PubMed1998

[Bio-mechanical property changes of long bone in ovariectomized goats].

This paper presents the biomechanical property changes of long bone in goats at 180 days after ovariectomy. 10 female goats at the age of 1.5 +/- years(average body wight 22 kg) were randomly divided into the control group and ovariectomized group. These goats were sacrificed at 180 days after ovariectomy and the femora, tibiae, metatarsus, humeri, radius and metacarpus were taken out bilaterally. The structural mechanical properties of these bones were measured with the three-point bending method. The material mechanical properties of flexura, compress and tensile in the compact bone specimens taken from the two broken ends were also measured. The results showed that the bone density, bone thickness in broken ends, and the break load of three-point bending for the long bones in the OVX group were obviously lower than those in the control group (P < 0.05). And compared with the control group all the long bones in the OVX group, except the femur, had significantly lower ultimate bending strength, bending elastic modulus; ultimate flexural strength, flexural elastic modulus; ultimate compressing strength, and compressing elastic moduus. Some long bones in the OVX group had significantly decreased ultimate tensile strength (P < 0.05). These indicated that the mechanical properties of long bone in OVX group at 180 days after ovariectomy were reduced in varying degrees and were liable to fracture. This result is in accord with the clinical findings in osteoporosis resulting from post-menopausal estrogen fall and is also consistent with the osteoporotic model of ovariectomized rats. The authors conclude that the bone biomechanical properties are important parameters in assessing osteoporosis and the ovariectomized goat can possible be a good big animal model of osteoporosis.

Animals↗
PubMed1998

[Application of time-frequency filter of wavelet to single-trail ERP extracting].

A new approach to extracting single-trail event-related potential(ERP) in combination with the correlation analysis has been proposed. This approach, called time-frequency filter, is based on the concept that multiresolution wavelet transforms. At first, an investigation of the properties in time and frequency domain was carried out on the ERP. On the basis of the findings, the time-frequency filter of wavelet was designed and used for single-trail ERP extracting. The results and related discussion are presented in this paper.

Adult↗
PubMed1998

[Approach to recognition of ECG P waves based on approximating functions].

A new method of recognizing ECG P waves based on approximating function is presented in this paper. The result of experiment demonstrates that the method based on the second order approximating functions to recognize P waves in useful and easy to do. The rate of correctness for recognizing P waves is higher than 99% according to MIT/BIH ECG Datebase.

Algorithms↗
PubMed1998

[A biomechanical evaluation of the effects of XW630 on the healing of experimental fracture].

The aim of this study was to evaluate whether tetracycline-estrone (XW630) plays a role in the healing of fracture. 120 rabbits were divided into 4 groups and subjected to osteotomies at the middle of both radials, and they were given XW630, estrone (E2), tetracycline (T) and 0.9% sodium chloride (C) respectively after operation by means of intramuscular injection (M) or local injection(L) in the fracture region. The biomechanical properties, including bending and compression, and the biochemical changes were tested at 30 days, 60 days and 90 days after osteotomy. The results showed that the bending stress and compression stress in the XW630(M) group were significantly higher than those in other groups at different periods after osteotomy. At 30 days after osteotomy, the bending ultimate stress in the XW630(M) group was 80% higher than that in group C, 76% higher than that in group E2, and 69% higher than that in group T. At 90 days after osteotomy, the bending ultimate stress in XW630(M) group increased to 80% of that of the normal radius, and it was 30% higher than that of group C, 34% higher than that of group E2 and 19.5% higher than that of group T. The biochemical changes corresponded with the changes biomechanical properties. These data suggest that XW630 given by intramuscular injection plays an obvious role in accelerating the healing of fracture. The medicine given by intramuscular injection is obviously more effective than that locally injected.

Animals↗
PubMed1998

[Effects of Curcuma phaeocaulis on learning and memory and lipid peroxide in mice].

Nine months mice were inoculated and the method of water maze test and lipid peroxide determination to study the effects of extract of Curcuma phaeocaulis Valeton on learning and memory ability and retarding of senescence. Results showed that in water maze test the time for the group with Curcuma phaeocaulis Valeton needed from initial position to the end was significantly shortened compared with old control. The error numbers for the group of Curcuma phaeocaulis Valeton were significantly decreased compared with old control after starting experiment for 18 days and 24 days and for 35 days no significance difference was showed between groups. The levels of brain, liver and red blood cells lipid peroxide in the group with Curcuma phaeocaulis Valeton were considerably lower than old control, hemoglobin content was considerably increased than old control.

Aging↗
PubMed1998

[GFAAS determination of trace Cr(III) and Cr(VI) after its separation by coprecipitation-floatation with aluminium hydroxide].

A method for determination of trace Cr(III) in natural water and drinking water by GFAAS after separation by coprecipitation-floatation with Al(OH)3 has been studied. Cr(VI) was determined also after being reduced by FeSO4. Conditions of Cr(III) floatation such as pH, the amount of floatation agent and coprecipitator-Aluminium added, the flow rate of nitrogen gas, the floatation time etc. were discussed. The influence of coexisting elements was investigated. The detection limit is 0.027 microg/L (n = 15). For Cr(III) concentration level of 0.5 microg/L, the RSD is 3.4% and the recovery of Cr(III) is 96.0-104.0%.

Aluminum Hydroxide↗
PubMed1998

[Room temperature phosphorimetric determination of practolol with dansyl chloride labeling].

Dansyl Chloride (DNS-Cl) was used as a phosphorescent labeling agent for the determination of practolol. The derivative was formed by refluxing practolol-ethyl acetate solution with the solid DNS-Cl in the presence of potassium carbonate anhydride. Room-temperature phosphorescent (RTP) properties of the derivative were studied by a micelle-stabilized room-temperature phosphorescence (MS-RTP) method. Phosphorescence lifetimes of practolol-DNS and the DNS-Cl were found to be 0.791 and 0.408ms, respectively. By applying the derivative MS-RTP technique, practolol could be quantitatively determined without previous separation process. Detection limit of practolol with the proposed method was 0.19 microg/mL.

Dansyl Compounds↗