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Biomedical subjects

Ke Li

Publications and source records attributed to Ke Li.

At least 55 records · Page 3Linked to original sources
PubMed2005

Characterization of the pharmacokinetics of dioscin in rat.

Dioscin (diosgenyl 2,4-di-O-alpha-l-rhamnopyranosyl-beta-d-glucopyranoside) is an important constituent of some traditional Chinese medicines with several bioactivities. We have investigated the pharmacokinetics of dioscin in rat after intravenous and oral administrations. Compartmental methods were used to perform pharmacokinetic data analysis. The dose-dependent pharmacokinetics of dioscin was characterized after intravenous administrations (0.064, 0.16, 0.4 and 1.0mg/kg) to rats. There was significant decrease in clearance with increasing dose (4.67+/-0.09 ml/min/kg (0.064 mg/kg) versus 3.49+/-0.23 ml/min/kg (1.0 mg/kg), P<0.05), and the plot of reciprocal clearance values versus the doses was linear (r=0.909, P<0.05). After an I.V. dose of 1mg/kg, simultaneous oral gavage of activated charcoal did not change the pharmacokinetic parameters indicating enterohepatic recycling of dioscin is not important in rat. The absolute oral bioavailability was very low (0.2%). In tissue distribution and bile excretion studies after I.V. and oral administrations, dioscin was shown to undergo a prolonged absorption from the intestinal tract and slow elimination from organs, and only a small amount of drug was recovered in bile. The cumulative amounts of dioscin in feces and urine indicated that the parent drug is mainly excreted in the feces.

Administration, Oral↗
PubMed2005

[A pig model of myocardial infarction by intracoronary embolization with gelatin sponge].

OBJECTIVE: We produced a large-animal model of myocardial infarction induced by transcatheter embolization of the left coronary artery using a gelatin sponge. METHODS: Seven pigs underwent transcatheter embolization of the left anterior descending artery (LAD) using gelatin sponge to produce anteroapical myocardial infarction (MI). 4 weeks later, Echocardiography, Coronary angiography and Pathology was performed, and the data were compared with those of the control group (n = 6). RESULTS: The procedure mortality was 1 of 7. In the MI group, the LV end-diastolic dimension increased (control versus MI: 37.0 mm +/- 3.4 mm and 50.8 mm +/- 6.1 mm, P < 0.01), the ejection fraction (EF) decreased (control versus MI: 62.3% +/- 2.9% and 36.6% +/- 2.1%, P < 0.001). Coronary angiography revealed the LAD remained occluded. The postmortem specimen showed a transmural MI scar in the anteroseptal and apical regions in the MI group and the LV volumes at 30 mm Hg were 81.4 ml +/- 4.3 ml, the scar areas were 18.4% +/- 1.6% of total left ventricular free wall and the scar thickness was 3.5 mm +/- 0.8 mm. Histologic samples in the MI group stained with Masson's trichrome showed massive fibrosis in the border zone and patchy fibrosis in the remote region in the LV free wall, whereas the control group showed no fibrosis. CONCLUSION: This pig model of myocardial infarction is reliable, reproducible, and similar to the human condition, amenable to investigate other investigation.

Animals↗
PubMed2005

In vitro neuronal differentiation of cultured human embryonic germ cells.

Human embryonic germ (hEG) cells, which have been advanced as one of the most important sources of pluripotent stem cells [the other one being human embryonic stem cells], can be propagated in vitro indefinitely in the primitive undifferentiated state while being capable of developing into all three germ layer derivatives, hence have become anticipated developing novel strategies of tissue regeneration and transplantation in the treatment of degenerative diseases. In the experiments here, we derived hEG cells from cultured human primordial germ cells (PGCs) of 6- to 9-week-post-fertilization embryos. They satisfied the criteria previously used to define hEG cells, including the expression of markers characteristic of pluripotent cells-abundant alkaline phosphatase (AP) activity, stage specific embryonic antigen (SSEA)-1(+), SSEA-3(-), SSEA-4(+), TRA-1-60(+), TRA-1-81(+), Oct-4(+), and hTERT(+), the retention of normal karyotypes, and possessing pluripotency by forming embryoid bodies (EBs) in vitro. Furthermore, these derived cells tended to neurally differentiate in vitro, especially under high-density culture conditions. We successfully isolated neural progenitor cells from differentiating hEG cultures and about 10% cells induced by 2microM all-trans-retinoic acid (RA) or 0.1mM dibutyryl cyclic AMP (dbcAMP)/1mM forskolin to mature neurons expressing microtubule-associated protein 2ab (MAP2ab), synaptophysin, beta-tubulin III, neuron-specific enolase (NSE), tyrosine hydroxylase (TH), but no glial fibrillary acid protein (GFAP) and choline acetyl transferase (ChAT). The data suggested that hEG cells may provide a potential source of cells for use in transplantation therapy for neurological degenerative diseases.

Biomarkers↗
PubMed2005

Fingerprint chromatogram analysis of extracts from the leaves of Tripterygium wilfordii Hook. F. by high performance liquid chromatography.

A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated for the study of fingerprint chromatograms of extracts from the leaves of Tripterygium wilfordii Hook. F. (TWHF) and for controlling the quality of the herb. HPLC separation of the extracts was performed on a Lichrospher RP-18 column and detected by ultraviolet absorbance at 210 nm. The column temperature was maintained at 35 degrees C. A mobile phase composed of acetonitrile:H2O in the ratio of 39:61 (v/v) was found to be most suitable for this separation at a flow rate of 0.8 mL/min with isocratic elution. Under the chromatographic conditions described, the peak profile of the 10 components collected within 35 min made up the fingerprint of the extracts from leaves of TWHF with universal features. The fingerprint chromatograms had a good stability, precision, and reproducibility. The similarity of the extracts from leaves of TWHF collected in summer and winter was studied with triptolide as a reference peak. The method is suitable for differentiation of extracts from the leaves of TWHF, and can be used as a quality control method for this herb.

Chromatography, High Pressure Liquid↗
PubMed2005

Liquid chromatography/tandem mass spectrometry for pharmacokinetic studies of 20(R)-ginsenoside Rg3 in dog.

A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the investigation of the pharmacokinetics of 20(R)-ginsenoside Rg3 in dog. The plasma samples were pretreated by liquid-liquid extraction and analyzed using LC/MS/MS with an electrospray ionization interface. Dioscin was used as the internal standard. The method had a lower limit of quantitation of 0.5 ng/mL for Rg3 in 200 microL of plasma or 2 ng/mL in 100 microL of plasma, which offered a satisfactory sensitivity for the determination of Rg3 in plasma. The intra- and inter-day precisions were measured to be below 8% and accuracy between -1.5 and 1.4% for all quality control samples. This quantitation method was successfully applied to pharmacokinetic studies of Rg3 after both an oral and an intravenous administration to beagle dogs. No Rh2 and protopanaxadiol were detected in plasma.

Administration, Oral↗
PubMed2005

DYRK gene structure and erythroid-restricted features of DYRK3 gene expression.

DYRKs are an emerging family of dual-specificity kinases that play key roles in cell proliferation, survival, and development. Up to seven mammalian DYRK isoforms have been reported, but only the DYRK1A gene (and its products) has been well characterized. Defined here are the genomic structures (and phylogenetics) of DYRK3, four additional murine and/or human DYRKs, and two related HIPK genes. For murine DYRK3, direct BAC sequences are provided, a basis for differential processing of murine versus human transcripts is defined, and tissue expression profiles plus a functional DYRK3 promoter are characterized. Unlike complex DYRKs 1A, 1B, and 4A, DYRK3 and DYRK2 possess simple 4-exon structures. For DYRK3, expression is strong in erythroid cells and testis, but is also detected in adult kidney and liver in situ. In addition, a 1930-bp DYRK3 promoter drives erythroid expression and transcript expression is inhibited sharply on GATA1-induced G1E cell differentiation.

Animals↗
PubMed2005

[The implementation of sharing treatment planning system based on DICOM].

Based on DICOM, three DICOM objects of RT S. S, RT Plan, RT Image are designed to implement the information sharing of different TPS, and to implement the information exchanging and sharing of the radiotherapy planning systems (TPS) of different manufacturers. The information exchange of different TPS based on DICOM is feasible.

Computer Communication Networks↗
PubMed2005

The effects of Chinese herb Angelica in focal cerebral ischemia injury in the rat.

This experiment was designed to study the therapeutic mechanisms of Angelica on the focal cerebral ischemia injury of the rat. The ischemic area was determined by TTC stain. And terminal deoxynucleotidyl transferase (TDT) mediated DUTP-biotin nick end labeling (TUNEL) method was applied to detect neuronal apoptosis. The expressions of Bcl-2 and Bax proteins were observed by immunohistochemical staining methods. Results show that the treatment with angelica reduced the volume of cerebral infarction (p < 0.05), and that the number of neuronal apoptosis cells decreased significantly (p < 0.01). Also the expression level of Bax protein decreased (p < 0.01). These results suggest that Angelica can reduce the number of apoptosis cells by decreasing the expression of Bax protein. This is maybe one of the mechanisms of the therapeutic effect of Angelica on focal cerebral ischemia injury.

Angelica↗
PubMed2005

[Simultaneous determination of pseudoephedrine hydrochloride and dextromethorphan hydrobromide in composite pseudoephedrine hydrochloride dry suspension by HPLC].

A simple and reliable reversed-phase high performance liquid chromatographic method (HPLC) for the routine analysis of pseudoephedrine hydrochloride and dextromethorphan hydrobromide in composite pseudoephedrine hydrochloride dry suspension has been established. HPLC determination for the drug was performed in a Lichrospher C6H6 column and detected at 220 nm. Acetonitrile-H2O-H3PO4 (50:50:0.1, v/v, pH 2.5, containing 1 g/L sodium dodecyl sulfate) was used as the mobile phase and the flow rate was 1.2 mL/min. The method was proved to be linear in the ranges of 1.03-206 mg/L and 5-200 mg/L for dextromethorphan hydrobromide and pseudoephedrine hydrochloride, respectively. The relative standard deviations of intra-assay (n = 7) and inter-assay (n = 5) were 1.0% and 1.5% for pseudoephedrine hydrochloride analysis and 1.8% and 2.2% for dextromethorphan hydrobromide analysis. The recoveries of pseudoephedrine hydrochloride and dextromethorphan hydrobromide were 95.7%-98.7% and 100.0%-101.8%, respectively. The method has been successfully applied to the simultaneous determination of pseudoephedrine hydrochloride and dextromethorphan hydrobromide in composite pseudoephedrine hydrochloride dry suspension.

Bronchodilator Agents↗
PubMed2005

[Neuronal activities related to right-sided mastication detected with functional magnetic resonance imaging].

OBJECTIVE: To observe neuronal activities related to right-sided mastication in cortex and to explore the effect of mastication on brain function. METHODS: Neuronal activities related to right-sided mastication were detected with functional magnetic resonance imaging in 10 healthy volunteers. Image data was analyzed by SPM99 software with the use of t test. RESULTS: Localization of activation in brain was different among subjects. Brain activation during mastication included left basal ganglion, Broca's area, angular gyrus and right supramarginal gyrus. CONCLUSIONS: The functional areas related to right-sided mastication and speech were closely connected, which indicated close relationship between mastication and speech. The central control of mastication might share part of common neural mechanism with that of speech. The roles of activated brain regions in mastication still remained to be elucidated.

Adult↗
PubMed2005

[Statistical analysis of clinicopathologic characteristics of 1075 cases with colonic cancer].

OBJECTIVE: To investigate the clinicopathologic characteristics of colonic cancer. METHODS: All clinical data of surgical cases from hospital registry from 1982 to 2002 were analyzed using SPSS 11.0 software. RESULTS: There were 1075 patients with colonic cancer including 573 males and 502 females. The median age of the patients was 58 years. 90.8% of the patients aged over 40 years . The proportion of right colonic cancer was 64.7%. Well-differentiated and moderately differentiated adenocarcinoma accounted for 69.8%, and mucous carcinoma 13.6%. The proportions of early stage I, advanced stage II, III and IV cancer were 8.1%, 45.0%, 26.5% and 20.3% respectively. The 5-, 10-year survival rates were 61.9% and 53.0% respectively. CONCLUSIONS: The risk for colonic cancer is significantly increased in patients over 40 years. The frequency of right colonic cancer is higher than that of left colonic cancer. The overall survival rate is high.

Adolescent↗
PubMed2005

[Protective effects of extract of Ginkgo biloba against ethanol-induced oxidative injury in rat testes].

OBJECTIVE: This study was designed to investigate whether EGB protect against ethanol-induced oxidative injury in rat testes. METHODS: The rats were pretreated with EGB (4.8,9.6 mg/100g bw per day) before 30% ethanol administration (2.37g/kg bw by gastric incubation). Ninety days later, the rats were killed in order to measure the activities of Superoxide Dismutase (SOD), Glutathione Reductase (GST), Glutathione Peroxidase (GSH-Px), Catalase (CAT) and the contents of Glutathione (GSH), Reactive Oxygen Species (ROS), Malondialdehyde (MDA)in rat testes. The microsomal fractions were obtained by the method of differential centrifugation, and HO-1 (Heme Oxygenase-1) activity in testicular microsomal was measured. To examine the expression of HO-1 mRNA by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Compared with ethanol group, ROS, and MDA contents significantly decreased in EGB group testes, respectively (P < 0.05). GST, GSH-Px, CAT, SOD activities, and GSH content in EGB group testes elevated markedly (P <0.05). EGB could enhance HO-1 mRNA expression remarkably. CONCLUSION: It is suggested that EGB as a preventive antioxidant can protect against ethanol-induced testicular injury, which may be associated with HO-1 activity enhancement, free radicals elimination, lipid per-oxidation reaction inhibition.

Animals↗
PubMed2004

UV photolysis of trichloroethylene: product study and kinetic modeling.

Direct UV photolysis of trichloroethylene (TCE) in dilute aqueous solution generated chloride ions as a major end product and several reaction intermediates, such as formic acid, di- and monochloroacetic acids, glyoxylic acid, and, to a lesser extent, mono- and dichloroacetylene, formaldehyde, dichloroacetaldehyde, and oxalic acid. Under prolonged irradiation, these byproducts underwent photolysis, and a high degree of mineralization (approximately 95%) was achieved. TCE decays through the following major pathways: (1) TCE + h nu --> ClCH=C*Cl + Cl*; (2) TCE (H2O) + h nu --> ClCH(OH)-CHCl2; (3) TCE + h nu --> HC[triple bond]CCl + Cl2; (4) TCE + h nu --> ClC[triple bond]CCl + HCl; (5) TCE + Cl* --> Cl2HC-C*Cl2. A kinetic model was developed to simulate the destruction of TCE and the formation and fate of byproducts in aqueous solution under irradiation with polychromatic light. By fitting the experimental data, the quantum yields for the four photolysis steps were predicted as phi(1) = 0.13, phi(2) = 0.1, phi(3) = 0.032, and phi(4) = 0.092, respectively. The reaction mechanism proposed for the photodegradation of TCE accounts for all intermediates that were detected. The agreement between the computed and experimental patterns of TCE and reaction products is satisfactory given the complexity of the reaction mechanism and the lack of photolytic kinetic parameters that are provided in the literature.

Kinetics↗
PubMed2004

High-performance liquid chromatographic detection of lipid peroxidation in human seminal plasma and its application to male infertility.

BACKGROUND: A simple and reliable high-performance liquid chromatographic (HPLC) method has been developed and validated for the analysis of malondialdehyde (MDA) in human seminal plasma. METHODS: After human seminal plasma is hydrolyzed, MDA is reacted with thiobarbituric acid (TBA) to form MDA(TBA)(2), a red-colored adduct with maximum absorbance at 532 nm. HPLC separation of the adduct in human seminal plasma was performed on a Lichrospher C(18) column. RESULTS: A mobile phase composed of 0.025 mol/l KH(2)PO(4) (pH 6.2)--methanol in the ratio 58:42 (v/v) was found to be the most suitable for this separation. Under the chromatographic conditions described, the MDA-TBA adduct had a retention time of approximately 4 min and good separation and detectability of MDA in human seminal plasma sample was obtained. The method proved to be linear calibration in the range of MDA from 0.10 to 2.50 micromol/l. The relative standard deviations of within- and between-assay for MDA analysis were 3.1% and 3.8%, respectively. The average recovery was 90.0-98.8% for the human seminal plasma samples. The method has been successfully applied to the study of the lipid peroxidation levels in the seminal plasma of male infertility. Semen samples were obtained from healthy volunteers and infertile males. Ejaculates were classified into studied subgroups and defined as: obstructive azoospermia, non-obstructive azoospermia, oligozoospermia, asthenozoospermia, oligoasthenozoospermia and oligoasthenoteratozoospermia. With the exception of obstructive azoospermic group, MDA concentrations of seminal plasma in control group had very significant difference with those in other infertile groups (P < 0.01). CONCLUSIONS: This indicated that lipid peroxidation could be harmful to male sperm and reproductive system, which may lead to male infertility.

Adult↗
PubMed2004

[Portal venous and enteric drainage in simultaneous pancreas kidney transplantation].

OBJECTIVE: To summarize the initial experience of simultaneous pancreas kidney transplantation (SPK) with portal venous and enteric drainage. METHODS: Between Jane 2001 and Jane 2003, SPK were performed in 5 patients. Systemic venous-enteric drainage (SED) was used in the first 2 patients and portal venous-enteric drainage (PED) in the last 3 cases. All patient were immunosuppressed with quadruple therapy, which included anti-CD25 mAb (Zenapax/Simulect) induction therapy, FK506, mycophenolate mofetil (MMF), and prednisone baseline therapy. The complications were analyzed. RESULTS: Serum glucose and renal function of the 5 cases were normal and no further insulin was needed within 7 days post-operation. No technique complications such as duodenal fistula and thrombosis were observed, One episode of acute rejection of kidney allograft occurred in one patient with SED, and resolved with a bolus corticosteroids. One case with SED and one with PED were died of sepsis and FK506 toxicity 4 weeks after transplantation. The death occurred with functioning pancreas graft. No latter complications were observed in the 3 survived patients with excellent graft functions. CONCLUSIONS: Both methods of SED and PED can be performed successfully and with no latter complications. But with its potential physiologic and immunologic advantages, PED might be a standard procedure for SPK.

Adult↗
PubMed2004

Elevation of NMDAR after transplantation of neural stem cells.

Cognitive deficits could be alleviated by transplantation of neural stem cells in animals. Grafted cells may differentiate into neurons, thereby improving animal cognition. Alternatively, grafted cells may provide neurotrophic factors to modify neuronal functions and to alleviate cognitive deficits. To test which mechanism is underlying this recovery process, senescence-accelerated mice were transplanted with human neural stem cells into the hippocampus. The effect of cell transplantation was assessed in the Morris water maze. The survival and differentiation of grafted cells and the expression of NMDA receptors were examined. The data suggested that in addition to the neural differentiation of grafted neural stem cells, up-regulation of NMDA receptors after transplantation also contributed to the alleviation of cognitive deficits in this animal model.

Aging↗
PubMed2004

[60]fullerene-stoppered porphyrinorotaxanes: pronounced elongation of charge-separated-state lifetimes.

A series of Sauvage-type porphyrinorotaxanes containing [60]fullerene stoppers have been synthesized by a convergent route. Photoinduced energy transfer and electron-transfer reactions in these rotaxanes yield long-distance charge-separated radical-pair states, whose lifetimes in solution at ambient temperatures are as high as 32 mus, depending on the distance between the fullerene and zinc porphyrin chromophores.

Journal Article↗