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Biomedical subjects

Ke Li

Publications and source records attributed to Ke Li.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Expression and identification of HCV core protein in human hepatocytes].

AIM: To construct the recombinant plasmid of HCV core protein, and to express and identify it in normal human hepatocyte HL-7702. METHODS: HCV core gene was cloned by using PCR from plasmid pBRTM/HCV1-3011 which included the full length of HCV gene. The core segment with expression plasmid pcDNA3.1(-) was recombined to construct eukaryotic expression plasmid pcDNA3.1(-)/core, which was then transfected into human hepatocytes by using poly-cation. The expression of core protein was detected by immunochemical staining and Western blot. RESULTS: The length and sequence of the cloned core segment were correct. The transfected HL-7702 cells expressed the core protein. CONCLUSION: The eukaryotic expression plasmid pcDNA3.1(-)/core including HCV core gene is successfully constructed. The effective expression of HCV core protein in human hepatocytes is useful for further development of HCV core antigen.

Blotting, Western↗
PubMed2006

Implantation of a drug delivery system during surgery for patients with primary hepatocarcinoma.

BACKGROUND: Postoperative regional chemotherapy is one of the most effective methods to decrease the recurrent rate and improve the prognosis of primary hepatocarcinoma (PHC). This study was undertaken to assess the optimal pathway to implant the drug delivery system (DDS) in the different ways of resecting PHC so as to offer a valuable reference to clinical implantation of the DDS. METHODS: One hundred and ninety cases were divided into two groups according to whether the tumors were resected completely (A) or not (B). Groups A and B were subdivided into three groups a, b and c according to the pathway selected for DDS implantation. The patients in subgroup a received DDS implantation through both the hepatic artery and portal vein (A+P-implanted group), the patients in subgroup b received DDS implantation through the portal vein (P-implanted group), and the patients in subgroup c received DDS implantation through the hepatic artery (A-implanted group). RESULTS: The 1- and 3-year recurrent rates of subgroup c in group A were higher than those of subgroup b, and there was no significant difference between subgroups a and b. Compared with subgroups a and c, the 1- and 3-year survival rates of subgroup b were similar to those of group a but higher than those of group c. The 1- and 3-year survival rates between subgroups a and b in group B were significantly different. The prognosis of subgroup c was lower than that of subgroup a and no significant difference was observed between subgroups b and c. CONCLUSIONS: The DDS should be implanted into the portal vein when PHC is resected completely. It may be better to implant it into both portal vein and hepatic artery if the tumor cannot be completely resected.

Antineoplastic Agents↗
PubMed2006

Promotive effect of C/EBPepsilon overexpression on differentiation of human myelomonocytic leukemia cell line U-937.

BACKGROUND & OBJECTIVE: CCAAT-enhancer binding protein omega (C/EBPepsilon) is a kind of nuclear transcriptional factor expressed predominantly in myeloid cells, and may be a critical regulator of myeloid differentiation, which can activate the transcription of a subset of myeloid-specific genes. This study was to detect the cell-specific expression of C/EBPepsilon, and to investigate the effect of C/EBPepsilon overexpression on c-Myc expression, cell cycle distribution, and cell differentiation of human myelomonocytic leukemia cell line U-937. METHODS: The expression of C/EBPepsilon in 5 hematopoietic cell lines (U-937, NB4, HL-60, K-562 and Jurkat T cell lines) was tested by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). According to the RT-PCR results, human myelomonocytic leukemia cell line U-937 was selected and transfected with pcDNA3.1-C/EBPepsilon32 expression vector by electroperforation, and screened by G418 to yield positive clones which were termed U-937-C/EBPepsilon32. The expression of C/EBPepsilon and c-Myc in U937-C/EBPepsilon32 cells was detected by RT-PCR and Western blot; cell cycle and differentiation of U937-C/EBPepsilon32 cells was analyzed by flow cytometry. RESULTS: C/EBPepsilon overexpression obviously increased the expression of CD11b (a cell surface marker of granulocyte maturity). The positive rate of CD11b was significantly higher in U-937-C/EBPepsilon32 cells than in U-937 and U-937-pcDNA3.1 cells(92.56% vs. 77.46% and 74.81%), while c-Myc expression and cell cycle had no changes. CONCLUSION: C/EBPepsilon might be an essential transcriptional regulator for U-937 cells differentiating into granulocytes.

CCAAT-Enhancer-Binding Proteins↗
PubMed2006

[Pathologic changes caused by highly pathogenic H5N1 avian influenza virus: postmortem study of a case].

OBJECTIVE: To report the postmortem findings of a case of highly pathogenic H5N1 avian influenza virus occurring in human beings. METHODS: Postmortem examination was carried out in a deceased caused by highly pathogenic H5N1 avian influenza virus. Detailed light microscopy of major organs, including heart, lungs, liver, spleen, kidneys and brain, was performed. The lung tissue was further investigated by histochemistry, immunohistochemistry and electron microscopy. RESULTS: Major histopathologic changes in lungs secondary to highly pathogenic H5N1 avian influenza virus included diffuse alveolar damage, hyaline membrane formation and focal hemorrhage. Some of the alveolar spaces contained lightly eosinophilic liquid, lymphocytes, macrophages, plasma cells and small number of neutrophils. Congested capillaries were commonly seen in the alveolar septa which were focally rimmed by hyaline membrane. Immunohistochemical study showed that the lymphocytes were mainly of T lineage and macrophages were also demonstrated. CONCLUSIONS: Highly pathogenic H5N1 avian influenza virus causes pathologic changes mostly in lungs, including diffuse alveolar damage and acute exudative changes (involving mainly T lymphocytes and macrophages). The resulting parenchymal destruction, consolidation, pulmonary edema and hemorrhage eventually lead to respiratory distress and death.

Adult↗
PubMed2006

[Biological function of CoQ10 and its effect on the quality of spermatozoa].

Oxidative damage is one of the important factors inducing the regression of sperm quality. CoQ10 is a liposoluble antioxidant that exists in mitochondria and its levels in semen and spermatozoa have an important role in the oxidation resistance of the male genital system. Exogenous administration of CoQ10 can improve the sperm quality and reproductive ability of infertile patients as well as exert the effects of an adjunctive therapy on male infertility. This review describes the biological function of CoQ10 and its effect on the quality of spermatozoa and its effect as an adjunctive therapy on male infertility.

Coenzymes↗
PubMed2005

Macrophages from C3-deficient mice have impaired potency to stimulate alloreactive T cells.

Impaired T-cell reactivity is a feature of C3-deficient mice in several disease models. The mechanism behind the reduced T-cell response is, however, poorly understood. We explored the hypothesis that antigen-presenting cells (APCs) from C3-/- mice have impaired potency to stimulate antigen-specific T cells, in an alloantigen-dependent model. Our results show that C3-/- macrophages have reduced ability to elicit alloreactive T-cell responses in vitro and in vivo, affecting both the primary and secondary responses. The C3 status of donor macrophages had a major impact on the CD4 T-cell response. The impaired CD4 T-cell response was associated with reduced expression of MHC class II on the surface of C3-/- macrophages, without loss of class II gene expression. Furthermore, inhibition of C3 gene expression in C3+/+ macrophages reduced their ability to stimulate alloreactive T cells, suggesting that endogenous production of C3 could in part contribute to the potency of APCs. Our data provide compelling evidence that C3 deficiency modulates the potency of APCs to stimulate the T-cell response, suggesting a critical role for complement in the maintenance of APC function. This could offer a partial explanation as to why the T-cell response is impaired in C3-/- mice.

Animals↗
PubMed2005

Cloning and characterization of a novel hepatitis B virus core binding protein C12.

AIM: To elucidate the biological function of HBV core antigen (HBcAg) on pathogenesis of hepatitis B, a novel gene C12 coding for protein with unknown function interacting with HBcAg in hepatocytes was identified and characterized. METHODS: HBcAg bait plasmid pGBKT7-HBcAg was constructed and transformed into yeast AH109, then the transformed yeast was mated with yeast Y187 containing liver complementary DNA (cDNA) library plasmid in 2XYPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-alpha-gal for screening twice. After extracting and sequencing of plasmid from blue colonies, we isolated a cDNA clone encoding a novel protein designated as C12 that directly interacted with HBcAg. The interaction between HBcAg and C12 was verified again by re-mating. pEGFP-N1-C12 fluorescent protein fusion gene was transfected in 293 and L02 cell, and observed by fluorescent microscope. MTT reduction assay was used to study the action of C12 protein effect on metabolism of mammal cell. Yeast two-hybrid and cDNA microarray were performed to search binding protein and differential expression genes regulated by C12 protein. RESULTS: C12 gene was screened and identified by yeast two-hybrid system 3. The interaction between HBcAg and the novel protein coded by the new gene C12 was further confirmed by re-mating. After 48 h, fluorescence of fusion protein could be observed steadily in the 293 and L02 cell plasma. Under MTT assay, we found that the expression of C12 did not influence the growth of liver cells. Seventeen differential expression genes in HepG2 cells transfected with C12 protein expression plasmid by cDNA microarray, of which 16 genes were upregulated and 1 gene was downregulated by C12 protein. Twenty-one colonies containing 16 different genes coding for C12 protein binding proteins were isolated by yeast two-hybrid, there were 2 new genes with unknown function. CONCLUSION: The novel protein C12 is located in cell plasma, and its overexpression has no significant effect on the metabolism of liver cell. It interacts with many proteins in hepatocytes and may be involved in many processes of gene expression.

Amino Acid Sequence↗
PubMed2005

Dissociation in the neural basis underlying Chinese tone and vowel production.

Neuropsychologists have debated over whether the processing of segmental and suprasegmental units involves different neural mechanisms. Focusing on the production of Chinese lexical tones (suprasegmental units) and vowels (segmental units), this study used the adaptation paradigm to investigate a possible neural dissociation for tone and vowel production. Ten native Chinese speakers were asked to name Chinese characters and pinyin (Romanized phonetic system for Chinese language) that varied in terms of tones and vowels. fMRI results showed significant differences in the right inferior frontal gyrus between tone and vowel production (more activation for tones than for vowels). Brain asymmetry analysis further showed that tone production was less left-lateralized than vowel production, although both showed left-hemisphere dominance.

Adult↗
PubMed2005

Lack of beta-methylamino-l-alanine in brain from controls, AD, or Chamorros with PDC.

High levels of beta-methylamino-l-alanine (BMAA), a putative neurotoxin, have been reported in brain samples from Chamorros and patients with Alzheimer disease (AD) from western Canada. The authors assayed free BMAA in the brains of five control subjects and five patients with AD from the US Pacific Northwest as well as Chamorros with and without Parkinson-dementia complex. In contrast to others, they detected no free BMAA in any of these samples.

Aged↗
PubMed2005

Visual attention deficits in Alzheimer's disease: an fMRI study.

Cognitive and neuroscience studies indicate that attentional operations are impaired in Alzheimer's disease (AD). Our goal was to define the anatomical areas of activation associated with visual attention processing and to define deficits or changes that may occur in AD patients compared with control group. Thirteen AD patients and 13 age- and education-matched normal controls were tested in two visual search tasks (one was a conjunction task, where feature binding is required. The other was a subset task, where group stimuli is needed without feature binding) using fMRI techniques. After stereotactical normalization, voxel-by-voxel t statistics was used to compare activated brain areas between patients and control subjects. Our findings suggest that both search tasks are controlled by partially overlapping cerebral networks, including parietal, frontal and occipital-temporal cortical regions and primary visual cortex. The AD patient group showed less activation in both parietal lobes and the left frontal regions, while increased activation was found in the right frontal lobes and the right occipito-temporal cortical regions with the conjunction task. In the subset task, decreased activation in AD patients was seen in the left parietal lobe and bilateral frontal lobes, while increased activation was seen in both medial temporal lobes. In addition, for the comparison between tasks, The difference is very small for AD patients. Control group showed a higher amplitude in the right prefrontal region, temporal cortical regions and parietal lobe. These results indicate that attention deficits in AD patients may be attributed to both binding problem and grouping inefficiency.

Aged↗
PubMed2005

[Visual search in Alzheimer disease--an functional magnetic resonance imaging study].

OBJECTIVE: To investigate the functional activation patterns during two types of visual search tasks in Alzheimer's disease (AD) with functional MRI, and probe the neuro-anatomic basis of visual attention. METHODS: 13 patients with AD and 13 sex and age-matched healthy subjects participated in the experiment designed with two visual search tasks. The first was a "pop-out" single feature task, detecting a vertical target among horizontal distractors, and the second was a conjunction task where the target was defined by conjunction of feature (color and orientation) and the performance depended on some shifting of attention. The fMRI data were collected by Siemens 1.5 T Sonata magnetic resonance imaging (MRI) system and analyzed by Statistical Parametric Mapping software (SPM 99) to generate the activation map. RESULTS: AD patients had a particular impairment in the conjunction task but not in the single-feature task. Although both groups revealed overlapping networks engaged in the conjunction tasks including the superior parietal lobule (SPL), frontal and occipitotemporal cortical regions (OTC), primary visual cortex and some subcortical structures, the most pronounced difference between them was found in bilateral SPL (more activities in the controls) and right OTC (more activities in the patients). The difference between the 2 groups was small in the pop-out condition. CONCLUSION: AD particularly affects those mechanisms controlling spatial shifts of attention. Some additional remote activation (ventral visual stream and temporal lobe) can be interpreted as dynamic reallocating of brain functional resource.

Aged↗
PubMed2005

CYP2E1-dependent hepatotoxicity and oxidative damage after ethanol administration in human primary hepatocytes.

AIM: To observe the relationship between ethanol-induced oxidative damage in human primary cultured hepatocytes and cytochrome P450 2E1 (CYP2E1) activity, in order to address if inhibition of CYP2E1 could attenuate ethanol-induced cellular damage. METHODS: The dose-dependent (25-100 mmol/L) and time-dependent (0-24 h) exposures of primary human cultured hepatocytes to ethanol were carried out. CYP2E1 activity and protein expression were detected by spectrophotometer and Western blot analysis respectively. Hepatotoxicity was investigated by determination of lactate dehydrogenase (LDH) and aspartate transaminase (AST) level in hepatocyte culture supernatants, as well as the intracellular formation of malondialdehyde (MDA). RESULTS: A dose-and time-dependent response between ethanol exposure and CYP2E1 activity in human hepatocytes was demonstrated. Moreover, there was a time-dependent increase of CYP2E1 protein after 100 mmol/L ethanol exposure. Meanwhile, ethanol exposure of hepatocytes caused a time-dependent increase of cellular MDA level, LDH, and AST activities in supernatants. Furthermore, the inhibitor of CYP2E1, diallyl sulfide (DAS) could partly attenuate the increases of MDA, LDH, and AST in human hepatocytes. CONCLUSION: A positive relationship between ethanol-induced oxidative damage in human primary cultured hepatocytes and CYP2E1 activity was exhibited, and the inhibition of CYP2E1 could partly attenuate ethanol-induced oxidative damage.

Cells, Cultured↗
PubMed2005

Acupoint-specific fMRI patterns in human brain.

Specific central nervous system (CNS) responses to acupuncture have recently attracted attention. It is important to understand the differences in fMRI images of the brain evoked by acupuncture at an acupoint and at a nearby "sham" point. Here, we report analyses of fMRI images of the brains of 37 healthy volunteers in response to acupuncture at Liv3 (Taichong) and LI4 (Hegu) versus their sham points. We found common activation areas in response to Liv3 or LI4 acupuncture in the middle temporal gyrus and cerebellum, along with deactivation areas in the middle frontal gyrus and inferior parietal lobule, compared with the effects of acupuncture at sham points. Acupuncture at Liv3 evoked specific activation at the postcentral gyrus, posterior cingulate, parahippocampal gyrus, BA 7, 19 and 41, but deactivation at the inferior frontal gyrus, anterior cingulate, BA 17 and 18, compared with acupuncture at its sham point. Acupuncture at LI4 evoked specific activation at the temporal pole, but deactivation at the precentral gyrus, superior temporal gyrus, pulvinar and BA 8, 9 and 45, compared with acupuncture at its sham point. These observations reveal that acupuncture at acupoints induces specific patterns of brain activity, and these patterns may relate to the therapeutic effects of acupuncture.

Acupuncture↗
PubMed2005

Development of a semi-quantitative food frequency questionnaire for middle-aged inhabitants in the Chaoshan area, China.

AIM: This paper aims to develop a data-based semi-quantitative food frequency questionnaire (SQFFQ) covering both urban and rural areas in the Chaoshan region of Guangdong Province, China, for the investigation of relationships between food intake and lifestyle-related diseases among middle-aged Chinese. METHODS: We recruited 417 subjects from the general population and performed an assessment of the diet, using a 3-d weighed dietary record survey. We employed contribution analysis (CA) and multiple regression analysis (MRA) to select food items covering up to a 90% contribution and a 0.90 R(2), respectively. The total number of food items consumed was 523 (443 in the urban and 417 in the rural population) and the intake of 29 nutrients was calculated according to the actual consumption by foods/recipes. RESULTS: The CA selected 233, 194, and 183 foods/recipes for the combined, the urban and the rural areas, respectively, and then 196, 157, and 160 were chosen by the MRA. Finally, 125 foods/recipes were selected for the final questionnaire. The frequencies were classified into eight categories and standard portion sizes were also calculated. CONCLUSION: For adoption of the area-specific SQFFQ, validity and reproducibility tests are now planned to determine how the combined SQFFQ performs in actual assessment of disease risk and benefit.

Body Mass Index↗
PubMed2005

[Regional modulation of primary motor cortex after peripheral nerve injury: a functional magnetic resonance imaging study].

OBJECTIVE: To map dynamic changes of primary motor cortex after total brachial plexus traction injury by using functional magnetic resonance imaging, and to explore underlying probable mechanisms. METHODS: Five patients with total traumatic root avulsions of the brachial plexus underwent varied kinds of nerve transfer to restore partially shoulder or elbow function. Four of them (cases 1, 3, 4, 5) accepted the first fMRI examination prior to surgery treatment, and four of them (cases 2, 3, 4, 5) accepted second or third or fourth fMRI follow-up re-examinations after surgery treatment. Maps of neuronal activation within the motor cortex were generated for both hands in each patient by using BOLD-fMRI and the cluster size and position were recorded. The motor tasks consisted of simple hand grasping of both hands respectively. Patients with paralytic hand were asked to complete task under "virtual" condition. The cluster size and intensity as well as location of motor activation within the primary motor cortex of the affected hand generated were compared with those of unaffected hand generated as reference in single subject, and the resultant maps of follow-up re-examinations were also compared with those of the prior examinations. RESULTS: All patients' unaffected hand movement generated strong signal change within the contralateral primary motor cortex. In contrast, the clusters generated by affected hand showed very small and lower intensity than usual (2 cases) or could not be induced (2 case) in the first examination that prior to surgery treatment and seemed larger gradually in the following re-examination with time increasing. CONCLUSION: Peripheral nerve injury can produced significant changes in the motor cortex of human brain. fMRI is a valuable tool to evaluate neural plasticity in motor cortex after peripheral nerve injury.

Adolescent↗
PubMed2005

Suppression of murine cerebral F2-isoprostanes and F4-neuroprostanes from excitotoxicity and innate immune response in vivo by alpha- or gamma-tocopherol.

Oxidative damage to brain is a featured shared by several destructive and degenerative diseases and is thought to contribute to disease pathogenesis. Two commonly proposed sources of the increased free radical stress that leads to oxidative damage in several of these diseases are excitotoxicity and activation of innate immunity, both of which are proposed pharmacologic targets. Here we used models of excitotoxicity, intracerebroventricular (ICV) kainate (KA), and innate immune activation, ICV lipopolysaccharide (LPS), to test the effectiveness of peripherally administered alpha-tocopherol (AT) and gamma-tocopherol (GT) as neuroprotectants. We quantified murine cerebral oxidative damage by measuring F(2)-isoprostanes (IsoPs) and F(4)-neuroprostanes (NeuroPs) using stable isotope dilution methods followed by gas chromatography-mass spectrometry with selective ion monitoring. Our data showed that peripherally administered AT and GT were equally effective at suppressing acute oxidative damage from direct excitotoxicity caused by KA. In contrast, peripherally administered AT, but not GT, was effective at suppressing delayed neuronal oxidative damage from activated glial innate immune response. These data imply that AT may be more broadly protective of cerebrum from oxidative damage in different disease contexts.

Animals↗
PubMed2005

Determination of dioscin in rat plasma by liquid chromatography-tandem mass spectrometry.

A sensitive and specific high-performance liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for dioscin in rat plasma was developed. Ginsenoside Rh2 was employed as an internal standard. Dioscin is a naturally occurring saponin present in many traditional Chinese medicinal plants. Dioscin was determined after the acetonitrile-mediated plasma protein precipitation. The mobile phase consisted of acetonitrile:10 mmol/l aqueous ammonium acetate (95:5, v:v), which was pumped at 0.8 ml/min. The analytical column (100 mm x 4.6 mm i.d.) was packed with Hypersil ODS material (5 microm). The standard curve was linear from 1 to 100 ng/ml. The assay was specific, accurate (percentage deviations from nominal concentrations were <10%), precise and reproducible (within- and between-day coefficients of variation <10%). Dioscin in rat plasma was stable over three freeze-thaw cycles and at ambient temperatures for 24 h. The utility of the assay was demonstrated by determining dioscin plasma concentrations in five rats for 120 h following a single oral gavage dose of 90 mg/kg.

Animals↗