Biomedical subjects

X Tao

Publications and source records attributed to X Tao.

At least 19 recordsLinked to original sources

PubMed2001

Calcium regulation of neuronal gene expression.

Plasticity is a remarkable feature of the brain, allowing neuronal structure and function to accommodate to patterns of electrical activity. One component of these long-term changes is the activity-driven induction of new gene expression, which is required for both the long-lasting long-term potentiation of synaptic transmission associated with learning and memory, and the activity dependent survival events that help to shape and wire the brain during development. We have characterized molecular mechanisms by which neuronal membrane depolarization and subsequent calcium influx into the cytoplasm lead to the induction of new gene transcription. We have identified three points within this cascade of events where the specificity of genes induced by different types of stimuli can be regulated. By using the induction of the gene that encodes brain-derived neurotrophic factor (BDNF) as a model, we have found that the ability of a calcium influx to induce transcription of this gene is regulated by the route of calcium entry into the cell, by the pattern of phosphorylation induced on the transcription factor cAMP-response element (CRE) binding protein (CREB), and by the complement of active transcription factors recruited to the BDNF promoter. These results refine and expand the working model of activity-induced gene induction in the brain, and help to explain how different types of neuronal stimuli can activate distinct transcriptional responses.

Animals↗

PubMed2001

[In vitro inhibitive effects of Tripterygium wilforii on NO production, iNOS activity, and iNOS-mRNA expression in chondrocyrtes of patients with rheumatoid arthritis].

OBJECTIVE: To study the mechanism of treatment of rheumatoid arthritis with Tripterygium wilfordii Hook. f. (TWHF). METHODS: Chondrocytes from the resected knee joint cartilage of patients with rheumatoid and TWHF, dexamethasone, or (arthritis were isolated and cultured. IL-1 indomethacin of different concentrations were added into the culture solution overnight. Griess reagent was added to the supernatant to detect the content of NO. Chondrocytes were collected to examine the iNOS activity by detecting the conversion of L-14C-arginine into L-14C-citruline. The total RNA of chondrocyte was extracted and the iNOS-mRNA was examined by Northern blotting. RESULTS: The inhibitory rates of NO production by TWHF of concentrations of 2 mg/L, 4 mg/L, 8 mg/L, and 16 mg/L were 10.8%, 25.48%, 55.17%, and 80.45% respectively. The inhibitory rates of iNOS activity by TWHF of concentrations of 2 mg/L, 4 mg/L, 8 mg/L, and 16 mg/L were 12.29%, 27.67%, 59.04%, and 85.06% respectively. Such inhibitory effects were dosage-dependent. TWHF ffectively inhibited the expression of iNOS-mRNA induced by IL-1 in chondrocyte (r = 0.976 and 0.974). Dexamethasone inhibited NO production, iNOS activity, and expression of iNOS-mRNA significantly but not dosage-dependently. Indomethcin only had weak inhibitory effect. CONCLUSION: TWHF inhibits NO production in chondrocytes by limiting the transcription of iNOS gene, which may be one of the mechanisms of treatment of RA with TWHF.

Arthritis, Rheumatoid↗

PubMed2001

COMO: a program for combined molecular replacement.

The combined molecular-replacement protocol uses a limited six-dimensional search to solve a structure by the molecular-replacement method, with the sampling of the rotational degrees of freedom guided by the rotation function. This protocol therefore automatically combines the information on the rotational and translational parameters of the search model. The combined molecular-replacement protocol has been implemented in a new computer program, COMO. The calculation of the Patterson correlation translation function has been optimized to improve its speed performance. A packing check is implemented that automatically removes impossible solutions and thereby increases the signal in the calculation. A family of atomic models can be used as the search model; the program will automatically select the model that gives the best result. The command interface is well organized and requires the definition of only a few critical parameters by the user. In addition, a graphical user interface has been constructed for the program. The program has been used to solve several difficult molecular-replacement problems. A case is presented where the program automatically determined the orientation and position of five copies of a search model in a high-symmetry space group.

Computer Simulation↗

PubMed2001

Effect of jianpiyiqi prescription on the expression of heat shock proteins in acetic acid-induced chronic gastric ulcer rats.

To investigate the effect of Jianpiyiqi prescription on the expression of heat shock proteins (HSPs) and the changes of HSPs in gastric-ulcerated rats, the rat model of chronic gastric ulcer was induced by acetic acid. The SABC immunohistochemical method was used to observe HSP70 of mucosa around the gastric ulcer. Imaging analysis was performed. Western dot blot was used to detect HSPs contents in the plasma and gastric mucosal homogenate in each group. The results showed that HSP70 contents of the mucosa around the gastric ulcer in the model group and ranitidine-treated group were increased as compared with control group (P < 0.01). Jianpiyiqi could increase the expression of HSP70 of the mucosa around the gastric ulcer further as compared with that in the model group and ranitidine-treated group (P < 0.01). The HSP70 contents in the serum and mucosa in the model group and ranitidine-treated group were increased as compared with control group (P < 0.01, P < 0.05 respectively). HSP70 of serum and mucosa in the Jianpiyiqi-treated group was higher than in the model group and ranitidine-treated group (P < 0.05, P < 0.01 respectively). It was concluded that HSP might play a role in the process of pathophysiology of gastric ulcer. Jianpiyiqi could enhance gastric ulcer-healing through the protective mechanism of HSPs.

Acetic Acid↗

PubMed2001

Arterial remodeling in chronic sinoaortic-denervated rats.

The spontaneous variation of blood pressure is defined as "blood pressure variability" (BPV). The chronic sinoaortic-denervated (SAD) rat is a model of high BPV without sustained hypertension. Little is known about vascular remodeling in this model. In the present study, we examined blood pressure, vascular remodeling, and aortic angiotensin II concentration in chronic SAD rats in separate experiments. In experiment 1, intra-arterial blood pressure was continuously recorded in conscious unrestrained rats. The 16-week SAD rats had a significant increase in BPV and no change in the mean level of blood pressure over a 24-h period. In experiment 2, we measured structural changes of seven kinds of arteries by histologic method and computer image analysis and functional changes of thoracic aortas by isolated artery preparation. Structural remodeling after 16-week sinoaortic denervation was characterized by increase in wall thickness, wall area, and ratio of wall thickness to internal diameter, with different changes in internal diameter and external diameter in different arteries, indicating that arterial structural remodeling expresses itself mainly as vascular growth. This vascular growth might be caused by medial smooth muscle cell growth and collagen accumulation. Aortic contraction induced by norepinephrine was potentiated, whereas aortic relaxation induced by acetylcholine was attenuated after sinoaortic denervation. In experiment 3, plasma and aortic angiotensin II concentrations were determined by radioimmunoassay. The former remained unchanged, whereas the latter was significantly increased in 10-week SAD rats. It is concluded that in rats chronic sinoaortic denervation can produce vascular remodeling that might be related to increased BPV and an activated tissue renin-angiotensin system.

Angiotensin II↗

PubMed2001

A phase I study of ethyl acetate extract of the chinese antirheumatic herb Tripterygium wilfordii hook F in rheumatoid arthritis.

OBJECTIVE: To explore the efficacy and safety of ethyl acetate (EA) extracts of the Chinese herbal remedy Tripterygium wilfordii Hook F (TWHF) for treatment of patients with a variety of inflammatory and autoimmune diseases including rheumatoid arthritis (RA). METHODS: The roots of TWHF were extracted sequentially by ethyl alcohol and ethyl acetate and the content of the extract documented. An open label, dose escalation Phase I study was performed in 1993 in 13 patients with established RA. Clinical manifestations and laboratory findings were examined before and every 4 weeks after starting treatment with the EA extract. RESULTS: Three patients withdrew from the trial during the first 16 weeks of the dose escalation. These patients received a maximum dosage of 180 mg/day. There were no adverse effects or disease improvement observed in these patients. Nine of the remaining 10 patients tolerated the EA extract up to a dosage of 570 mg/day. There were no withdrawals related to adverse events in the trial except for one patient who developed diastolic hypertension at a dose of 180 mg/day of EA extract. Six of 10 patients treated with 180 mg/day of EA extract showed disease improvement. Eight of the 9 patients who received EA extract at doses > 360 mg/day experienced improvement in both clinical manifestations and laboratory findings. One patient met American College of Rheumatology criteria for remission. CONCLUSION: The EA extract of TWHF at dosages up to 570 mg/day appeared to be safe, and doses > 360 mg/day were associated with clinical benefit in patients with RA.

Acetates↗

PubMed2001

[An epidemic investigation of eperythrozoonsis in Shandong province].

OBJECTIVE: To learn the status of infection of eperythrozoonsis in Shandong province. METHODS: Seven hundred and seventy-six human blood samples, 198 domestic animal blood samples and 114 wild rat blood samples were collected. Eperythrozoon was detected in the human and animal blood stain slides under microscope. RESULTS: Overall infection rate of Eperythrozoon in human population was 7.3%. Rates were significantly different (P < 0.01) in different districts but no significant difference was found between men and women (P > 0.05). The rate among adults was higher than that of teenagers and elderly. It was also noticed that the rates of people affected with chronic diseases as hepatitis, diabetes and arthritis were higher than those without. The infection rates of goat, cows and rats were 15.6%, 3.2% and 0, respectively. CONCLUSION: Data showed that Eperythrozoon infection was intensively identified in the people and animals in Shandong province.

Adolescent↗

PubMed2001

[Analysis on the present situation of human rabies epidemic in China].

OBJECTIVE: To summarize and analyze human rabies epidemic situation in the last five years in China and to explore the possible factors causing the rising of epidemics to provide reference for the prevention and control of rabies in the future. METHODS: Collecting and analyzing data of rabies epidemics in the last five years in whole nation. RESULTS: Human rabies is continuing going up in the last five years in China with an increase of 44.65%, 1.74% and 45.93% in 1997, 1998, 1999. Human rabies incidence was also seen an increase from 0.0134/100,000 in 1996 to 0.02708/100,000 in 1999. The provinces of rabies increase were mainly located in south China. Among them, Jiangsu province reported 40 human cases in 1999, which increased 207.69% than the corresponding period in 1998. The cases in these high epidemic provinces took up 75% of the whole nation's cases. Number of reported rabies case was also rising. CONCLUSION: Facts as increasing number of dog raising, having not been injected with rabies vaccine and antirabies serum timely or full course after exposure, unstrictly controlling the quality of rabies vaccine as well as lacking good cooperation in different official department on rabies control might serve as factors responsible for the recurrent increase of human rabies.

Animals↗

PubMed2001

[A new interpretation for "Knockout Drops" (menghan)].

Knockout drops ("menghanyao" in Chinese) is named as one of riddles in the cultural history of China. Why its is named as "menghan" has been interpreted from the viewpoint of phonology by many former solons. A new opinion is put forward from the viewpoint of pharmacology and physiology in this paper, in which a historical fact is concerned that mandala is the essential component in knockout drug. The function of sweat gland is inhibited with sweat retained inside the human body after knockout drops are taken. "Menghan" just describes the above physiological phenomenon.

China↗

PubMed2000

Structural basis for signal transduction by the Toll/interleukin-1 receptor domains.

Toll-like receptors (TLRs) and the interleukin-1 receptor superfamily (IL-1Rs) are integral to both innate and adaptive immunity for host defence. These receptors share a conserved cytoplasmic domain, known as the TIR domain. A single-point mutation in the TIR domain of murine TLR4 (Pro712His, the Lps(d) mutation) abolishes the host immune response to lipopolysaccharide (LPS), and mutation of the equivalent residue in TLR2, Pro681His, disrupts signal transduction in response to stimulation by yeast and gram-positive bacteria. Here we report the crystal structures of the TIR domains of human TLR1 and TLR2 and of the Pro681His mutant of TLR2. The structures have a large conserved surface patch that also contains the site of the Lps(d) mutation. Mutagenesis and functional studies confirm that residues in this surface patch are crucial for receptor signalling. The Lps(d) mutation does not disturb the structure of the TIR domain itself. Instead, structural and functional studies indicate that the conserved surface patch may mediate interactions with the down-stream MyD88 adapter molecule, and that the Lps(d) mutation may abolish receptor signalling by disrupting this recruitment.

Amino Acid Sequence↗

PubMed2000

The Chinese anti-inflammatory and immunosuppressive herbal remedy Tripterygium wilfordii Hook F.

Various preparations of Tripterygium wilfordii Hook F (TwHF) have been used in the treatment of a number of autoimmune and inflammatory diseases since the 1960s. Accumulated data from the clinical trials suggest efficacy of this treatment in a number of rheumatic diseases, including rheumatoid arthritis and systemic lupus erythematosus. Studies on the relationship of the chemical components of TwHF and its immunosuppressive and anti-inflammatory effects suggest that diterpenoid compounds with epoxide groups account for the therapeutic effects of this herbal remedy. This herbal remedy is therefore a unique and powerful alternative therapy for autoimmune and inflammatory diseases.

Animals↗

PubMed2000

Correlation of genetic polymorphism of cytochrome P4502D6 with dextromethorphan oxidative metabolism in Chinese.

OBJECTIVE: To determine the genetic mechanism of dextromethorphan oxidative polymorphism in Chinese subjects. METHODS: CYP2D6 genotype was analyzed by polymerase chain reaction (PCR) and Hph I restriction fragment length polymorphism (RFLP) techniques in 119 healthy Chinese subjects. RESULTS: The gene frequency of CYP2D6*10B was 58.4%, including 13(10.9%) of homozygous wild type(w/w), 33 (27.7%) of homozygous mutant(m/m), and 73(61.3%) of heterozygous genotypes(m/w). Twenty-nine subjects out of 42 intermediate metabolizers(70%) of dextromethorphan were homozygous for CYP2D6*10B. One poor metabolizer subject also showed an m/m genotype. Besides, 10 Chinese subjects were tested and excluded for the presence of any of the six mutant alleles associated with poor metabolism of CYP2D6 in Caucasians. CONCLUSION: The CYP2D6*10B allele containing the C(188)--> T mutation is the major cause of CYP2D6 polymorphism in relation to diminished dextromethorphan oxidative capacity in Chinese subjects.

Adolescent↗

PubMed2000

Hepatitis B virus X protein activates expression of IGF-IR and VEGF in hepatocellular carcinoma cells.

OBJECTIVE: The expression of insulin-like growth factor I receptor (IGF-IR) and the vascular endothelial growth factor (VEGF) in HepG(2) cells transfected with a hepatitis B virus X (HBx) expression vector was investigated in an attempt to study their possible relationship to the growth of HBx-induced hepatocellular carcinoma (HCC). METHODS: The eucaryotic expression vector of HBx gene was constructed and introduced into HepG(2) cells. The modified cell HepaG(2)-X was synchronized in a quiescent state by culture of serum deprivation. The IGF-IR and VEGF were analyzed by immunohistochemical and Western blot technique. RESULTS: The positive rate of IGF-IR expression was 84%A3% in the transfected HBx gene cells, 26%A4% in X(0) control cells. The positive rate of VEGF expressed x cells was 83%A5%, X(0) cells was 28%A6% (P<0.001). The level of IGF-IR and VEGF in serum-starved x modified cells was 1.5 times higher than that of synchronized X(0) modified cells. CONCLUSION: Since the IGF-IR is a very important growth factor in sustaining the tumor abnormal growth and the VEGF has a crucial role in inducting tumor angiogenesis, our findings indicate that HBx may play an important role in the processes of HCC by activating IGF-IR and VEGF gene expression.

Carcinoma, Hepatocellular↗

PubMed2000

[Effect of unsymmetrical cutting along both river slopes on rainstorm-runoff process].

A simulation experiment was conducted to compare the effect of cutting and no-cutting at both slopes along a river on the rainstorm run-off in catchment, and a model was constructed. The results showed that the appearance of outflow and peak flow of surface run-off was later on forest slope than on forest-cutting slope. On forest slope, the duration was prolonged, and the peak flow and surface runoff were lower. These effects were more obvious as the slope gradient was bigger. When rain intensity was 1.98 mm.min-1 and rainfall was 108.8 mm, the peak flow and the total runoff on both forested slopes of gradient 15 degrees was 5% and 4% less than that on the cutting slopes, respectively.

Rain↗

PubMed2000

[The application study of mimic operation with 3D-cut in maxillofacial bone tumor].

OBJECTIVE: To study the feasibility of guiding operation planning and complication prevention. METHODS: Ten patients suffer from Maxillofacial bone tumour were examined with spiral CT. Firstly, to get three-dimensional reconstructive image of tumour and other tissues. Secondly, use 3D-cut software to cut off every layer of normal tissue and tumour mass. Lastly, to compare virtual operation with mimic operation in virtual operation process. RESULTS: Three-dimensional mimic operation clearly displays the relationship between tumor and surrounding tissues, reflect the actual operation condition. CONCLUSIONS: It is very useful designing operation program and predicting the potential complications before the actual operation.

Adult↗

PubMed1999

Mutagenic drinking water and risk of male esophageal cancer: a population-based case-control study.

Drinking mutagenic downstream water from the Huangpu River was hypothesized to have increased the risk for male esophageal cancer in Shanghai, China. The authors conducted a population-based case-control study of a total of 71 esophageal cancer deaths and 1,122 controls collected during a 5-year follow-up period, 1984-1988, from four male cohorts born before January 1, 1944, living in four communities consuming water with different mutagenicities in the Shanghai area. The controls represented a 1% random sample of the defined living cohorts selected at the end of each of the 5 years of follow-up. Logistic regression showed an odds ratio of 2.77 (95% confidence interval: 1.52, 5.03) for drinking mutagenic downstream water from the river versus drinking nonmutagenic upstream water after controlling for possible confounders including age, disease history (hepatitis, cirrhosis, schistosomiasis, digestive tract ulcer), hazardous occupational history, pesticide exposure, lifestyle factors (cigarette smoking, tea intake, and alcohol intake), dietary habits (intake of pickled vegetables, maize, peanuts, and cured meat), education, poverty, urban environment, and water chlorination.

Adult↗

PubMed1999

Suppression of carrageenan-induced inflammation in vivo by an extract of the Chinese herbal remedy Tripterygium wilfordii Hook F.

OBJECTIVE AND DESIGN: The current studies investigated the effect of subacute administration of an ethyl acetate extract of the Chinese herbal remedy, Tripterygium wilfordii Hook F (TWHF) on the inflammatory response induced by carrageenan in the rat. MATERIALS AND SUBJECTS: F344 rats were randomly divided into 3 groups of seven animals. TREATMENT: The rats were treated orally for 5 days with either vehicle or an ethyl acetate extract of TWHF at a dose of 270 mg/kg, equivalent to 1/5 of the dose causing death in 50% of the animals. METHODS: Air pouches were induced subcutaneously on the backs of rats and injected with carrageenan on the last day of treatment. Sixteen hours after carrageenan challenge, the air pouches were removed and analyzed. Student's t-test was employed for statistical analysis. RESULTS: The number of exudate cells and the concentration of PGE2, nitrite and TNF-alpha in the exudate obtained from TWHF-treated animals were significantly reduced (by 69%, 78%, 57% and 77%, respectively) compared to that from vehicle-treated animals. mRNA for cyclooxygenase-2 was markedly suppressed in the air pouch lining tissue of TWHF treated rats (p < 0.001). In contrast, PGE2 content of the kidney and stomach and the production of PGE2, nitrite and TNF-alpha by spleen cells was not affected by treatment with TWHF. CONCLUSIONS: These results indicate that TWHF exerts a significant anti-inflammatory activity in vivo.

Acetates↗

PubMed1999

Predictors of compliance with recommended cervical cancer screening schedule: a population-based study.

BACKGROUND: The prevalence of routine cervical cancer screening and compliance with screening schedules are low compared to the Year 2000 objectives. Identifying predictors of routine screening and screening schedule compliance will help achieve these objectives. METHODS: We analyzed data from probability samples of 1,609 Missouri women responding to both the 1994 Behavioral Risk Factor Surveillance System (BRFSS) and the Missouri Enhanced Survey (ES). We generated prevalence odds ratios to identify predictors of non-compliance to cervical cancer screening guidelines. Also, among a sample of women reporting a reason for last Pap test, we estimated the relative odds of a screening v. diagnostic exam. RESULTS: In the combined probability sample, compliance with screening schedule was likely among women younger than 50 years of age and women who had either a recent mammography or a clinical breast exam. Being African-American, not experiencing a cost barrier when seeking medical care, having at least a high-school education and health coverage were each associated with an increased compliance with a screening schedule in the combined probability sample. Among women in the combined probability sample, whites, those who experienced no cost barrier to seeking medical care, the non-obese, and those who had a recent mammography were each more likely to have had a screening as opposed to a diagnostic exam. DISCUSSION: Cancer control and cardiovascular (CVD) prevention programs should consider jointly targeting those at high risk for cervical cancer and CVD because of aging and associated high-risk behavior such as non-compliance with cervical cancer screening, smoking, and obesity. Also, further research is needed to examine whether the increased compliance with cervical cancer screening guidelines among African American women may be in part due to higher occurrence of diagnostic Pap smears.

Adult↗