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Biomedical subjects

Z M Liu

Publications and source records attributed to Z M Liu.

At least 19 recordsLinked to original sources
PubMed2005

Cell death induced by ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid in anaplastic thyroid carcinoma cells is via a mitochondrial-mediated pathway.

The chemical compound ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F), isolated from the Chinese herbal medicine plant Pteris semipinnata L, has been known to exert antitumor activity. However, the molecular mechanism of the action is not understood. In this study we demonstrated that apoptotic cell death induced by 5F in FRO cells was concentration- and time-dependent. The rapid increase in intracellular reactive oxygen species (ROS) levels was involved in the mechanism of cell death. c-Jun N-terminal kinase (JNK) activation and G2 block were related to cell death induced by 5F. Extracellular signal-related kinase (ERK) and p38 were also activated, but as survival signals in response to 5F treatment to counteract the induction of cell death. In the process of the induction of apoptotic cell death, Bax translocated into mitochondria, a reduction in Delta psi(m) was observed and a release of cytochrome c and apoptosis inducing factor (AIF) from mitochondria into the cytosol occurred, indicating that cell death induced by 5F was through a mitochondrial-mediated pathway.

Apoptosis Inducing Factor↗
PubMed2004

Heme oxygenase-1 protects against apoptosis induced by tumor necrosis factor-alpha and cycloheximide in papillary thyroid carcinoma cells.

Heme oxygenase-1 (HO-1) plays a role in the resistance to apoptosis of several types of cells, but its role in the development of thyroid cancer is unknown. In this study, we investigated the regulation of HO-1 in human papillary thyroid carcinoma cells (KAT5). The results show that HO-1 is significantly induced by hemin and cadmium. In addition to inducing HO-1, hemin and cadmium also cause a rise in the levels of p21, a cyclin-dependent kinase inhibitor. Cells with increased levels of HO-1 and p21 were more resistant to apoptotic stimuli than cells with normal levels. The cells resistant to apoptosis also displayed an increased arrest at the G(0)/G(1) phase of the cell-cycle. The induced levels of HO-1 and p21 were significantly reduced by p38 mitogen-activated protein kinase (p38 MAPK) and extracellular-regulated kinase (ERK) inhibitors. More importantly, KAT5 cells regained their sensitivity to apoptotic stimuli after they were treated with these kinase inhibitors, indicating that p38 MAPK and ERK are required for the resistance to apoptosis conferred by HO-1. Furthermore, we demonstrated that increased levels of HO-1 and p21 expression are associated with an increase in the activity of NF-kappaB and that inhibiting NF-kappaB leads to a block in the induction of HO-1 and p21. In summary, this study reveals that an increase in the level of HO-1 markedly reduces the sensitivity of papillary thyroid carcinoma cells to apoptotic stimuli. The HO-1 pathway of apoptosis resistance is associated with an increase in the levels of p21, involves a p38 MAPK and ERK-mediated mechanism and can be suppressed by inhibiting NF-kappaB.

Apoptosis↗
PubMed2001

Association of BMI with the beta3-adrenergic receptor gene polymorphism in Japanese: meta-analysis.

OBJECTIVE: To assess the effect of the Trp64Arg polymorphism in the beta3-adrenergic receptor gene (ADRB3) on body mass index (BMI) in the Japanese population. RESEARCH METHODS AND PROCEDURES: We selected studies that evaluated the association between BMI and ADRB3 polymorphism among Japanese, using MEDLINE and PubMed. After data collection, an extension of ANOVA was performed to assess the differences according to the genotype. RESULTS: In a total of 35 subgroups including 2316 subjects with the Trp64Arg variant and 4266 subjects without this variant, the weighted mean difference in BMI was 0.26 kg/m(2) (95% confidence interval: 0.18 to 0.42; p < 0.01), indicating that variant carriers exhibited higher BMI than did normal homozygous subjects. DISCUSSION: Although it is known that the allele frequency of the ADRB3 polymorphism differs among races, this study focuses on the Japanese population, which has a high allele frequency of ADRB3 polymorphism. We assumed that statistical errors would be prevented due to the sufficient number of subjects. In conclusion, the results support the hypothesis that ADRB3 gene polymorphism is associated with BMI.

Alleles↗
PubMed2001

[The package and identifying of hNT-3 recombinated retroviral vector].

hNT-3 was inserted into retroviral vector pLXSN to get pLXSN-NT3, and it was transfected into packaging cell line PA317 to form G418 resistant cell clones. The G418 resistant clones were titered and checked for the existence of replication viral. Genome DNA isolated from the cell clone of highest titeration showed the function gene, hNT-3 cDNA, had integrated into the genome of host cells verified by PCR. And bioassay of the clone's cell culture supernant exhibited that it can induce neurite over-growth in the primary culatures of rat spinal cord dorsal root ganglions as compared with controls.

Animals↗
PubMed2001

[The design of detection circuit for DNA biosensor].

The paper describes the design of a quartz crystal sensor for the detection of DNA hybridization reaction. With the ssDNA as probe on the electrode surface, we can detect the frequency change and show it on the computer display. The design is capable of real time monitoring for frequency change of DNA hybridization reaction.

Biosensing Techniques↗
PubMed2000

Nutrient intake of adult women in Jilin Province, China, with special reference to urban-rural differences in nutrition in the Chinese continent.

OBJECTIVES: The objectives of this study were to investigate possible urban-rural differences in food intakes in Jilin province and in continental China as a whole, and to examine possible implications for nutritional status of urban and rural populations. DESIGN: Cross-sectional study. SETTING: Communities. SUBJECTS: In total, 499 adult women in six urban sites and four rural sites, 10 sites in total, including two sites in Jilin province. METHODS: A pair of surveys were conducted in September, 1999, in the provincial capital of Changchun and a farming village in Dehui county, both in Jilin province, in northeast China. Each of 50 adult women per survey site provided a 24 h duplicate food sample and a blood sample, and had an interview on health history including anthropometry and blood pressure measurement. Nutrient intakes were estimated from the food duplicates, using national food composition tables. Results from the two sites were supplemented with data from eight sites where surveys had been conducted following the same protocol, and the pooled material were subjected to analyses for possible urban-rural differences. RESULTS: The Jilin participants consumed daily, on average, about 1600 kcal energy, 44 g protein, and 60 g lipid with a lipid energy ratio (i.e. the ratio of lipid over total nutrients in terms of energy) of 33%. When nutrient intakes were compared between the urban (i.e. Changchun) and rural (Dehui) groups, urban women consumed more energy, protein (especially animal protein) and lipid than rural women. Similar examination of data from six urban and four rural sites, including the present two, showed that adult women in urban areas eat more animal protein and animal fat than their counterparts in villages, and suggested that the observation on urban rural difference in Jilin province can be extrapolated to a nationwide scale. CONCLUSIONS: Urban rural differences in nutrient intakes still persist in 1999 not only in Jilin but in other provinces, typically in the terms of intakes of animal-based foods.

Adult↗
PubMed2000

Two novel genes induced by hard-surface contact of Colletotrichum gloeosporioides conidia.

Germinating conidia of many phytopathogenic fungi must differentiate into an infection structure called the appressorium in order to penetrate into their hosts. This differentiation is known to require contact with a hard surface. However, the molecular basis for this requirement is not known. Induction of this differentiation in the avocado pathogen, Colletotrichum gloeosporioides, by chemical signals such as the host's surface wax or the fruit-ripening hormone, ethylene, requires contact of the conidia with a hard surface for about 2 h. To study molecular events triggered by hard-surface contact, we isolated several genes expressed during the early stage of hard-surface treatment by a differential-display method. The genes that encode Colletotrichum hard-surface induced proteins are designated chip genes. In this study, we report the characterization of CHIP2 and CHIP3 genes that would encode proteins with molecular masses of 65 and 64 kDa, respectively, that have no homology to any known proteins. The CHIP2 product would contain a putative nuclear localization signal, a leucine zipper motif, and a heptad repeat region which might dimerize into coiled-coil structure. The CHIP3 product would be a nine-transmembrane-domain-containing protein. RNA blots showed that CHIP2 and CHIP3 are induced by a 2-h hard-surface contact. However, disruption of these genes did not affect the appressorium-forming ability and did not cause a significant decrease in virulence on avocado or tomato fruits suggesting that C. gloeosporioides might have genes functionally redundant to CHIP2 and CHIP3 or that these genes induced by hard-surface contact control processes not directly involved in pathogenesis.

Amino Acid Sequence↗
PubMed2000

Protective effect of melatonin on methylmercury-Induced mortality in mice.

Effect of melatonin on the mortality in methylmercury chloride (MMC)-intoxicated mice was evaluated. Mice were given MMC in the diet (40 mg Hg/g) with or without melatonin in drinking water (20 mg/ml) for 5 weeks. In the control group, given MMC alone, 4 of 10 mice began to show neurological signs (e.g., abnormal righting reflex, staggering gaitfallen and posture on its side) concomitant with loss of body weight 4-7 days before death. This group also showed 60% of survival rate on the 35th day. However, the treated group, concomitantly given melatonin, showed a 100% of survival rate on the 35th day, although 1 of 10 mice began to show the neurological signs on the 33rd day. The level of thiobarbituric acid reactive substance in the brain, as an indication of oxidative damage, showed a significant decrease in the treated group compared with the control group. Thus, the 100% survival rate in the treated group may be partly due to antioxidative effect of melatonin on the MMC induced neurotoxicity.

Animals↗
PubMed2000

Hepatitis B and C virus infection among adult women in Jilin Province, China: an urban-rural comparison in prevalence of infection markers.

Twin seroepidemiological surveys on prevalence of hepatitis B and C virus (HBV and HCV, respectively) infection were conducted on 100 adult women in total, 50 each in the provincial capital of Changchun and in a farming village in the vicinity in Jilin Province, northeast China. Positivity to three markers on HBV (ie HBsAg+, anti-HBs+, and anti-HBc+) was examined by RIA methods, and to one on HCV (anti-HCV+) by EIA. The results were evaluated in combination with two foregoing studies in Shandong and Shaanxi Provinces, and with special reference to possible urban-rural differences in prevalence. The prevalence of HBsAg+ cases was rather low (ie 9% when two groups were combined), but that of anti-HBs+ and anti-HBc+ cases was high, being 50% and 45%, respectively. Thus, the rate of HBV+ cases was 62%. The rate for HCV+ cases was 3%. The comparison of the prevalence between the city group and the village group showed that the rates for anti-HBs+ and HBV+ were significantly or marginally higher in the former group than in the latter, respectively. The HCV+ prevalence rate for the city group (4%) also tended to be higher than the corresponding rates for the village group (2%), although the difference was statistically insignificant. When evaluated together with the observation in Shandong and Shaanxi Provinces, it appears possible to generalize that the HBV infection prevalence is not higher and probably lower in rural areas than in urban areas, and that such may also be the case for the HCV infection prevalence.

Adult↗
PubMed1999

Early expression of the calmodulin gene, which precedes appressorium formation in Magnaporthe grisea, is inhibited by self-inhibitors and requires surface attachment.

Fungal conidia contain chemicals that inhibit germination and appressorium formation until they are well dispersed in a favorable environment. Recently, such self-inhibitors were found to be present on the conidia of Magnaporthe grisea, and plant surface waxes were found to relieve this self-inhibition. To determine whether the self-inhibitors suppress the expression of early genes involved in the germination and differentiation of conidia, the calmodulin gene was chosen as a representative early gene, because it was found to be expressed early in Colletotrichum gloeosporioides and Colletotrichum trifolii differentiation. After calmodulin cDNA and genomic DNA from M. grisea were cloned, the promoter of the calmodulin gene was fused to a reporter gene, that for green fluorescent protein (GFP), and transformed into the M. grisea genome. Confocal microscopic examination and quantitation of expression of GFP green fluorescence showed (i) that the expression of the calmodulin gene decreased significantly when self-inhibition of M. grisea appressorium formation occurred because of high conidial density or addition of exogenous self-inhibitors and (ii) that the expression level of this gene was restored when self-inhibition was relieved by the addition of plant surface waxes. The increase in fluorescence correlated with the percentage of conidia that formed appressoria. The induction of calmodulin was also confirmed by RNA blotting. Concanavalin A inhibited surface attachment of conidia, GFP expression, and appressorium formation without affecting germination. The high correlation between GFP expression and appressorium formation strongly suggests that calmodulin gene expression and appressorium formation require surface attachment.

Biological Factors↗
PubMed1999

Drug dependence and abuse potential of tramadol.

AIM: To assess the drug dependence and abuse liability of tramadol. METHODS: Subjects of opiate addicts with history of tramadol abuse were 219. Physical dependence of tramadol was assessed using opiate withdrawal scale (OWS), psychic dependence was assessed by association test of Addiction Research Center Inventory-Chinese Version (ARCI-CV); the degrees of craving experienced for tramadol was self-reported on visual analogue scale (VAS). RESULTS: The scores of OWS of tramadol were 0.05-1.07; 3 scores on scales in particular being used the identify euphoric effects--MBG, sedative effects--PCAG, and psychotomimetic effects--LSD of ARCI were 7.3, 6.1, and 3.4, respectively (F = 38.1, P < 0.01); 57.1% of tramadol abuse subjects had craving for tramadol (chi 2 = 75.86, P < 0.01). CONCLUSION: Tramadol produced high abuse potential among opiate addicts.

Adult↗
PubMed1998

Identification of a gene product induced by hard-surface contact of Colletotrichum gloeosporioides conidia as a ubiquitin-conjugating enzyme by yeast complementation.

The germinating conidia of many phytopathogenic fungi on hosts must differentiate into an infection structure called the appressorium in order to penetrate their hosts. Chemical signals, such as the host's surface wax or fruit ripening hormone, ethylene, trigger germination and appressorium formation of the avocado pathogen Colletotrichum gloeosporioides only after the conidia are in contact with a hard surface. What role this contact plays is unknown. Here, we describe isolation of genes expressed during the early stage of hard-surface treatment by a differential-display method and report characterization of one of these cloned genes, chip1 (Colletotrichum hard-surface induced protein 1 gene), which encodes a ubiquitin-conjugating enzyme. RNA blots clearly showed that it is induced by hard-surface contact and that ethylene treatment enhanced this induction. The predicted open reading frame (ubc1Cg) would encode a 16.2-kDa ubiquitin-conjugating enzyme, which shows 82% identity to the Saccharomyces cerevisiae UBC4-UBC5 E2 enzyme, comprising a major part of total ubiquitin-conjugating activity in stressed yeast cells. UBC1Cg can complement the proteolysis deficiency of the S. cerevisiae ubc4 ubc5 mutant, indicating that ubiquitin-dependent protein degradation is involved in conidial germination and appressorial differentiation.

Amino Acid Sequence↗
PubMed1998

Effect of inhaled interleukin-4 on airway hyperreactivity in asthmatics.

lnterleukin-4 (IL-4) has been shown to play a crucial role in the pathogenesis of allergic disease including bronchial asthma. In order to investigate the role of IL-4 in airway hyperreactivity, we investigated the effect of inhaled recombinant human IL-4 on airway responsiveness to methacholine and eosinophil numbers in induced sputum in eight patients with allergic asthma using a placebo-controlled study design. Our results demonstrated that in the control experiments receiving vehicle inhalation, methacholine PC20 values did not change nor did the numbers of eosinophils in sputum change from baseline values. In contrast, after IL-4 inhalation, methacholine PC20 fell from baseline (0.43 +/- 1.81 mg/mI) to 0.22 +/- 1.73 mg/mI (p < 0.01) at 24 h, and to 0.21 +/- 1. 74 mg/ml (p < 0.01) at 48 h. Accompanying this increased airway sensitivity was a significant eosinophilia in sputum. Our data indicated that IL-4 increases airway responsiveness by recruiting eosinophils into the airway in patients with allergic bronchial asthma.

Administration, Inhalation↗
PubMed1998

Melatonin: a chemical photoperiodic signal with clinical significance in humans.

Secretion of pineal melatonin exhibits a diumal rhythm and a seasonal rhythm in humans. Night-time melatonin is high at 3-5 year-old and decreases with age. Many drugs and pathological conditions also change melatonin levels in the circulation. Melatonin has a mild sedative effect and has been used effectively in synchronizing the sleep-wake cycle of patients with sleep disorders. Immunoenhancing, anti-cancer, anti-aging and anti-oxidant effects of melatonin have been proposed. Recent studies suggest that melatonin receptors are present in central and peripheral tissues. The importance of melatonin receptors on the nervous, reproductive, immune and renal functions is implicated. Studies on the molecular biology, physiology and pathology of melatonin receptors in different tissues are progressing rapidly. The physiological and pathological changes in melatonin secretion, multifarious melatonin actions, and diverse melatonin receptors reported suggest that melatonin is a photoperiodic signal with clinical significance in humans.

Animals↗
PubMed1997

Kinesin-73 in the nervous system of Drosophila embryos.

Kinesin-73 cDNA was shown to encode a kinesin heavy chain protein that contains an N-terminal motor domain and a long central region that lacks extensive coiled-coils. The amino acid sequence of the motor domain of kinesin-73 protein is most closely related to the motor domains of Caenorhabditis elegans unc-104 and mouse KIF1A. The central region of kinesin-73 protein also is related to unc-104 and KIF1A, but the homology is lower than that of the motor domain. The C-terminal region of kinesin-73 protein contains a cytoskeleton associated protein Gly-rich domain, which is a putative microtubule binding site that is present in some cytoskeleton or dynein-associated proteins. Kinesin-73 mRNA was shown by in situ hybridization to be maternally expressed and widely distributed in the syncytial blastoderm embryo. However, later in Drosophila embryo development, expression of the kinesin-73 gene becomes restricted mostly to the central and peripheral nervous systems.

Amino Acid Sequence↗
PubMed1997

Antioxidative and chelating activities of phenylpropanoid glycosides from Pedicularis striata.

AIM: To study the antioxidative and iron chelating activities of phenylpropanoid glycosides (PPG) isolated from a Chinese herb Pedicularis striata. METHODS: Antioxidative effects of PPG on lipid peroxidation induced by FeSO4-edetic acid in linoleic acid were measured by thiobarbituric acid method. Chelating activities of PPG for Fe2+ were tested by differential spectrum method. RESULTS: The reaction rates (A532.min-1) of lipid peroxidation were 0.0046 in the control, 0.0021 in verbascoside group, and 0.0008 in isoverbascoside group. The chelating activity of isoverbascoside was 2-fold stronger than that of verbascoside. Permethyl verbascoside showed neither antioxidative nor chelating activities. CONCLUSION: The inhibitory effects of PPG with phenolic hydroxy groups on lipid peroxidation are owing to their chelating properties. Under physiological condition PPG-Fe2+ chelates are sufficiently stable. Thus PPG are able to inhibit the Fe(2+)-dependent lipid peroxidation in vivo through chelating Fe2+ and exhibit their therapeutic potential by the same mechanism in vitro.

Antioxidants↗