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Biomedical subjects

X Tao

Publications and source records attributed to X Tao.

At least 37 records · Page 2Linked to original sources
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

The clinical application of computerized three-dimensional mimic operation for maxillofacial bone tumor.

Facial bone, as the frame to support maxillofacial region and with several sinuses and cavities, is structurally complicated and the maxillofacial tumors, benign or malignant, in this region usually grows into the deep tissues, sinus-cavities and orbit and destroys the bone. In this study, the maxillofacial tumors were subjected to a mimic operation on a computer following CT scanning and 3-dimensional reconstruction. The data similar to those of real operation were obtained, which could be used for developing operative plans. As compared with data on the basis of conditions in the real operation, computerized mimic operation reflected the real conditions during operation. Computerized mimic operation is valuable for the preoperative planning and the prediction of probable intraoperative events.

Bone Neoplasms↗
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↗
PubMed1999

[The transactivation of hepatitis B virus X protein on the expression of Fas ligand in HepG2 cells].

OBJECTIVE: To study the effect of hepatitis B virus x (HBx) protein on the expression of Fas Ligand in HepG2 cells. METHODS: The open reading frame of HBx gene was obtained from HBV genome (subtype adw) digested with Nco I and Bgl II, then cloned into pCEP4. The reconstructive plasmid pCEP4x was transfected into HepG2 cells by electroportion method. After selecting with hygromycin B, resistant clonies were obtained. The expressions of HBx gene and Fas Ligand gene were detected by RT-PCR. Immunohistochemical staining and western blot analysis. RESULTS: It showed that Fas Ligand gene expressed in the modified HepG2 cells transfected with plasmid pCEP4x. CONCLUSIONS: The results suggest the expression of Fas Ligand in HepG2 cells could be activated by HBx protein.

Cell Line↗
PubMed1999

[The effect of hepatitis B virus x protein on cell cycling].

OBJECTIVE: To study the effect of HBx protein on cell cycle progression and its molecular mechanism. METHODS: The eucaryotic expression vector pCEP4 of HBx gene was constructed and introduced into HepG2 cells. The HepG2 cells transfected with X gene (X cell) were synchronized in a quiescent state by culture of serum deprivation. Flow cytometry, immunohistochemical and Western Blot analysis were performed. RESULTS: 70% HepG2 cells transfected with pCEP4 (X0 cells) was induced in G0-G1 phase, only 56% X cells in G0-G1 phase, almost identical to its parental HepG2 cells cultured in serum medium. To further understand the molecular mechanism of cell cycle progression, the p21CIP1/WAF1 and PCNA were examined. HBx was found to strongly increase the level of PCNA in X cells (86 +/- 3)% compared with X0 cells (9 +/- 5)%, and greatly decrease the level of p21CIP1/WAF1 protein in X cells (16 +/- 6)% compared with X0 cells (86 +/- 8)% (P < 0.001). CONCLUSIONS: These data suggest a molecular mechanism by which HBx likely contributes to viral carcinogenesis. By deregulating cell cycle checkpoint control, HBx could participate in the selection of cells that are genetically unstable, some of which would accumulate unrepaired transforming mutations.

Adaptor Proteins, Signal Transducing↗
PubMed1999

[Assessment of vigilance for patients with sleep disordered breathing].

OBJECTIVE: Assessment of vigilance for patients with sleep disordered breathing. METHODS: Vigilance of the patients referred to sleep study for suspected sleep disorders was evaluated prospectively by a computerized driving simulator SteerClear before (evening) and after (next morning) nocturnal sleep study. The vigilance was quantified by means of the averaged percentages of obstacle hitting made during the evening and the morning driving test, abbreviated as %Hm. Controls included 11 normal volunteers. Kruskal-Wallis ANOVA by Rank was used to compare the %Hm in patients with that in normal controls; Spearman Rank Correlation was used to analyze the relationship between %Hm and parameters obtained from sleep study. RESULTS: The %Hm in normal subjects and in patients were (expressed as median and range): normal subjects 0.6 (0 - 2.5), n = 11; sleep snoring 1.1 (0.2 - 2.0), n = 7; obstructive sleep apnea syndrome (OSAS) 2.2 (0.2 - 7.7), n = 22; central sleep apnea syndrome (CSAS) 2.7 (0.9 - 5.4), n = 6. The %Hm of the patients with OSAS and CSAS but not the patients with sleep snoring (P > 0.05) was significantly higher than that of normal subjects (P < 0.05). Among the normal subjects, the patients with OSAS or with sleep snoring, there existed a significant correlation between the %Hm and the percentage of cumulated time spent at the oxygen saturation below 90% (r = 0.41, n = 40, P < 0.05), whereas the %Hm was not correlated to apnea/hypopnea index (r = 0.22, n = 40, P > 0.05) nor to arousal index (r = 0.10, n = 17, P > 0.05). CONCLUSIONS: The vigilance of the patients with OSAS or CSAS but not those only with sleep snoring is impaired, the impairment may relevant to the oxygen desaturation during their sleep.

Adult↗
PubMed1999

[Analysis of MRI and CT manifestations of paranasal sinuses and orbitocranial disorders with secondary exophthalmos].

OBJECTIVE: To study the MRI and CT manifestations of paranasal sinuses and orbitocranial disorders with secondary exophthalmos. METHODS: MRI and CT scans of 51 patients were examined. RESULTS: MRI offers more information for evaluation of soft tissue lesions; the cavernous hemangioma and dermoid cyst were found to present rather characteristic images. Whereas in evaluation of lesions involving bony structures and calcifications, CT was superior to MRI. CONCLUSION: CT and MRI may evaluate the tumor location, extension into adjacent areas and are valuable in differential diagnosis of paranasal sinuses and orbitocranial disorder with secondary exophthalmos.

Adolescent↗
PubMed1998

Relation of hemoglobin measured at different times in pregnancy to preterm birth and low birth weight in Shanghai, China.

This paper addresses two questions: 1) What is the relation of hemoglobin in the second gestational month to preterm birth and low birth weight? 2) How does the relation differ when hemoglobin in the fifth or eighth month or the lowest pregnancy hemoglobin are examined in place of first trimester values? These relations were examined prospectively in 829 women from Shanghai, China in 1991-1992. The population was nearly homogeneous by race, parity, antenatal care, and smoking. Rates of birth outcomes were compared between hemoglobin categories based on 10 g/liter groupings, with 110-119 g/liter as the reference group. Rates of low birth weight and preterm birth (but not small-for-gestational age) were related to early pregnancy hemoglobin concentration in a U-shaped manner. The relative risks (95% confidence intervals) for preterm birth in women by g/liter of hemoglobin were 2.52 (0.95-6.64) for > or = 130 g/liter, 1.11 (0.41-2.99) for 120-129 g/liter, 1.64 (0.77-3.47) for 100-109 g/liter, 2.63 (1.17-5.90) for 90-99 g/liter, and 3.73 (1.36-10.23) for 60-89 g/liter. Use of hemoglobin values in the fifth or eighth month attenuated the association with preterm birth. When lowest pregnancy hemoglobin values were used, the association of anemia with both outcomes was obscured, and risk of preterm birth at high hemoglobin values increased dramatically.

Adult↗
PubMed1998

The relationship between synonymous codon usage and protein structure.

The hypothesis that synonymous codon usage is related to protein three-dimensional structure is examined by investigating the correlation between synonymous codon usage and protein secondary structure. All except two codons in E. coli show the same secondary structural preference for alpha-helix, beta-strand or coil as that of amino acids to be encoded by the respective codons, while 17 codons show secondary structural bias in mammalian proteins. The results indicate that there is no significant correlation between synonymous codon usage and protein secondary structure in E. coli, but there is a correlation in mammals. It could be deduced that synonymous codons carry much less structural information in prokaryotes than in eukaryotes due to their divergent evolutionary mechanism.

Animals↗