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T Li

Publications and source records attributed to T Li.

At least 109 records · Page 6Linked to original sources
PubMed2001

Species-specific identification of human hookworms by PCR of the mitochondrial cytochrome oxidase I gene.

Significant differences in the life histories of the human hookworms Ancylostoma duodenale and Necator americanus necessitate their differentiation for epidemiological studies and the design of control programs. Current methods of identification require time-consuming, labor-intensive techniques. A polymerase chain reaction (PCR)-based method that enables rapid species identification is described. The mitochondrial cytochrome oxidase I genes of both species were sequenced, and species-specific primer sets were designed. The primers were used in PCR to amplify 585-bp fragments of the cytochrome oxidase gene from individual hookworm eggs, larvae, and adults. The technique was also able to identify mixed infections containing equal amounts of eggs from each species. The technique is rapid, technically simple, and sensitive and will permit the accurate identification of human hookworms in epidemiological field studies.

Ancylostoma↗
PubMed2001

[Cases-Control association study and transmission disequilibrium test of T102C polymorphism in 5HT2A and Tourette syndrome].

OBJECTIVE: To investigate whether T102C polymorphism in 5HT2A (serotonin receptor 2A) is associated with Tourette syndrome. METHODS: Both case-control association analysis and Transmission Disequilibrium Test(TDT), in addition to polymerase chain reaction and RFLP technique were used in 157 trios with Tourette syndrome (TS) and 120 controls. A semi-structured "Schedule for Tourette and other behavioral syndrome" was used in family history-collecting. Both the criteria of "Diagnostic and Statistical Manual of Mental Disorders"(DSM-IV) and that of Tourette syndrome association (TSA) were used in the diagnosis of Tourette syndrome and related disorders. RESULTS: The association between T102C polymorphism in 5HT2A and Tourette syndrome comorbided with obsessive compulsive disorder (OCD) was found by genotype-wise analysis (chi(2)=8.38,P=0.004) and allele-wise analysis (chi(2)=4.84,P=0.028), which was further confirmed by TDT analysis (chi(2)=5.12,P=0.02). No evidence of association or transmission disequilibrium between 102T/C polymorphism in 5HT2A and this disease in pure TS and total TS sample was found. CONCLUSION: 102T/C polymorphism in 5HT2A is exclusively associated with Tourette syndrome comorbided with DSM-IV OCD, which may constitute an independent subtype of Tourette syndrome.

Adolescent↗
PubMed2001

Enhanced continent mechanism of tapered ileum by extramural support from the pouch and abdominal walls: a preliminary report of a clinical study.

PURPOSE: We constructed a reliable continent tube that is easy to catheterize and surgically simple. MATERIALS AND METHODS: Eight patients with bladder cancer underwent a procedure in which ileal segment was tapered as an efferent tube, of which a part was placed between the back surface of the rectus muscle and the ileal pouch wall. The internal orifice of the tapered ileum was anastomosed to the ileal pouch and its external orifice was anastomosed to the umbilicus. Urodynamic and radiological studies were done postoperatively in 7 cases. RESULTS: The stoma was easily catheterized with a 16Fr catheter in all cases. One patient died of heart disease 55 days postoperatively, while 6 of the remaining 7 were completely continent day and night. Urodynamic study of the efferent tubes showed that maximum close pressure with the pouch full was significantly higher than with the pouch empty (p <0.001). Retrograde radiography of the efferent tubes demonstrated perfect canalization without stenosis. CONCLUSIONS: This study indicates that the continent mechanism of tapered ileum may be greatly enhanced by fixing it between the abdominal and pouch walls. This maneuver also provides easy catheterization and surgical simplicity.

Abdominal Muscles↗
PubMed2001

[Association analysis of attempted suicide and 5-HT2A receptor gene].

OBJECTIVE: To examine the relationship of attempted suicide with A-1438G and T102C polymorphisms of 5-HT2A receptor gene. METHODS: Genotypes and allele frequencies of A-1438G and T102C polymorphisms of 5-HT2A receptor gene in 149 attempted suicides and 190 normal controls were examined by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). RESULTS: No differences in genotypes and allele frequencies of A-1438G and T102C polymorphisms of 5-HT2A receptor gene were observed between attempted suicides and the controls. However, an association between male attempted suicides and genotype(GG) of A-1438G polymorphism was found. CONCLUSION: These results suggested that liability to suicide behavior might be associated with A-1438G polymorpyhism of 5-HT2A receptor gene in male subjects.

Adolescent↗
PubMed2001

A role for the Tubby-like protein 1 in rhodopsin transport.

PURPOSE: To test the hypothesis that a lack of Tubby-like protein 1 (TULP1) function causes aberrant transport of nascent rhodopsin and to examine the functional relationship between the homologous proteins TULP1 and Tubby by studying mice carrying combined mutations. METHODS: Subcellular localization of TULP1 and rhodopsin in photoreceptors was determined by immunofluorescence and by postembedding immunoelectron microscopy. Mice carrying different tulp1/tubby allele combinations were examined by histology, electroretinograms (ERGs), and immunofluorescence microscopy. RESULTS: TULP1 is distributed throughout the photoreceptor cytoplasm but is excluded from the outer segments and the nuclei. In the tulp1-/- mice, ectopic accumulation of rhodopsin occurs at an early age. Both the vesicular profiles in the interphotoreceptor space and the inner segment plasma membranes are immunoreactive for rhodopsin. Mice doubly homozygous for null mutations in the tulp1 and tubby genes initially develop photoreceptors and express a battery of photoreceptor markers at age 14 days. Thereafter their photoreceptors undergo a fulminant degeneration that reaches completion by postnatal day 17. The disease phenotype in the double homozygote is much more severe than either single homozygote. Double heterozygotes are phenotypically normal. CONCLUSIONS: A lack of TULP1 function results in misrouting of nascent rhodopsin. TULP1 may be a component of the cellular machinery that targets nascent rhodopsin to the outer segments. Comparison of disease phenotypes in the single and double mutants suggests that TULP1 and Tubby are not functionally interchangeable in photoreceptors nor do they form an obligate functional complex.

Animals↗
PubMed2001

The value of apparent diffusion coefficient maps in early cerebral ischemia.

BACKGROUND AND PURPOSE: Prediction of the regions of the ischemic penumbra that are likely to progress to infarction is of great clinical interest. Whether lowered apparent diffusion coefficient (ADC) values were present in the ischemic penumbra of patients presenting with acute ischemic stroke and were specific to regions of the penumbra that proceeded to infarction was investigated. METHODS: Nineteen patients with hemispheric stroke of less than 6 hours' onset and with acute scans showing a perfusion lesion greater than a diffusion lesion (ischemic penumbra) were studied. Scans also were performed subacutely (days 3 to 5) and at outcome (day 90). The outcome scan was used to identify regions of the penumbra that proceeded to infarction. RESULTS: The ADC ratios were significantly reduced (P <.00001) in regions of the penumbra that progressed to infarction on the outcome scan compared with those that remained normal. In regions that showed transition to infarction, the mean ADC ratios were typically 0.75 to 0.90. CONCLUSION: Intermediate ADC values are present in the ischemic penumbra and are indicative of tissue at risk of infarction.

Aged↗
PubMed2001

[Linkage disequilibrium analysis of chromosome 22 and schizophrenia in a Chinese population].

OBJECTIVE: To explore the molecular genetic relations of chromosome 22 and schizophrenia and locate the susceptibility gene of schizophrenia. METHODS: Six dinucleotide tandem repeat loci on chromosome 22 were chosen to analyze 126 affected sib-pair nuclear families of schizophrenia in Chinese population by fluorescent labeled auto-mated genotyping and transmission/ disequilibrium test(TDT). RESULTS: The TDT-chi square value of IL2Rbeta was 25.30(P=0.01), which suggests there is linkage disequilibrium between IL2R beta and schizophrenia. The P vaules of the other five loci (D22S944, D22S264, D22S303, D22S278 and CYP2D6) were greater than 0.05. CONCLUSION: A susceptive gene of schizophrenia may be located in IL2Rbeta locus or adjacent region.

Chromosomes, Human, Pair 22↗
PubMed2001

Effects of repeated +Gz exposures on lipid peroxidation of various organs in rats.

OBJECTIVE: To investigate the change of lipid peroxidation in various organs of rats after repeated +10 Gz stress. METHOD: Twenty male Wistar rats were randomly divided into control (+1 Gz) group and +10 Gz group (n = 10 for each group ). The two groups were exposed to +1 Gz or +10 Gz on an animal centrifuge respectively. The onset rate of +Gz was 0.5 G/s; the sustained time at peak +Gz was 30 s each time, with 5 times/d, 1 min intervals, 3 d/wk, 3 wk in total. The rats were decapitated in ice bath on the next day after the last +Gz exposure. The lung, heart, liver and kidney of rats were collected for the following determinations. These organs were made into homogenates and the mitochondria of heart and kidney were isolated from their homogenates. Then malondialdehyde (MDA) content , superoxide dismutase (SOD) activity and glutathion (GSH) concentration in these homogenates and mitochondria were determined individually. RESULT: Compared with the control, MDA concentration in myocardial mitochondria increased significantly (P < 0.01) after repeated +10 Gz exposures, and the SOD activity in liver homogenate and renal mitochondria decreased remarkably (P < 0. 01). But there was no significant difference between GSH concentrations of the two groups. CONCLUSION: Repeated +10 Gz stress induced lipid peroxidation injury of myocardial mitochondria and had some influences on the oxygen radical metabolism of liver and kidney in rats.

Animals↗
PubMed2001

Collection of buccal cell DNA in seventh-grade children using water and a toothbrush.

We developed a simple and effective method for collecting a large quantity of buccal cell DNA in school-based studies of seventh-grade and older children. Seventh-grade students at schools in Wuhan, China brushed each buccal surface with a soft toothbrush and then rinsed with 10 ml of water. We added 5 ml of 99% ethanol to preserve the sample. Among 1563 samples transported at room temperature over 1 week and then stored for 13-14 months at -70 degrees C before extraction, using a modified Gentra Puregene protocol, the median total DNA yield was 108 microg, range of 14 to 416 microg. We assayed every 20th sample (n = 77) for NAT2 by the PCR, and all samples gave a 1093-bp product. From the 1563 samples, we obtained a result for single nucleotide polymorphisms in the interleukin-13 gene (at +2044) by RFLP-PCR on 98.8% and in the promoter of the myeloperoxidase gene (at -463) by real-time PCR on 99.7%. A water-rinse method, that we used among 12th-grade students in Southern California, gave a lower total DNA yield than the toothbrush rinse (median of 17 microg) and a slightly reduced ability to generate a PCR product. However, 26 of 27 water-rinse samples gave a result for two genes, albumin and CYP1A1, using real-time PCR methods. We did not quantify human, versus bacterial, DNA in our samples. However, given the amounts of total DNA required for genotyping, a sample with the median yield of 108 microg should suffice for approximately 2160 genotypes by RFLP-PCR methods or five times as many by real-time PCR. We recommend the toothbrush-rinse method, combined with a modified Gentra Puregene DNA extraction protocol, for large-scale, in-person collections of buccal cell DNA in children. The method requires only inexpensive, readily available materials and produces a large quantity of high-quality DNA for PCR analyses.

Albumins↗
PubMed2001

[Inhibitory effects of tea polyphenols and vitamin C on lipid peroxidation induced by FeSO4- cysteine in isolated human plasma and carbon tetrachloride-induced liver free radical injury in mice].

OBJECTIVE: To investigate the inhibitory effects of tea polyphenols (TP) and Vitamin C (Vit C) on FeSO4-cysteine induced lipid peroxidation in isolated human plasma and carbon tetrachloride (CCl4) induced liver free radical injury in mice. METHOD: The experiment included two parts: (1) In FeSO4-cysteine induced lipid peroxidation system of isolated human plasma, malondialdehyde (MDA) content was detected after administration of different concentrations of TP (0.3 ~ 8.1 mg/L, as C ~ F group) and Vit C (3 ~ 81 mg/L, as G ~ J group) respectively; (2) Thirty-six male Kunming mice were randomly divided into four groups: control group (A), CCl4 damage group (B), TP protection group (C) and Vit C protection group (D). TP or Vit C (100 mg/kg) was given orally to group C and D respectively, while the same volume of distilled water was given to the other two groups one time every day, continued for three days. Twelve hours after the final treatment, CCl4 (230 mg/kg) was given orally to group B ~ D. Thirty six hours later, all the mice were decapitated and liver homogenate were prepared for measuring MDA content. RESULT: In FeSO4-cysteine induced lipid peroxidation in isolated human plasma, the inhibitory rate of TP (0.3 ~ 8.1 mg/L) was 30.7%, 32.0%, 46.9% and 59.7 %, and the inhibitory rate of Vit C (3 ~ 8.1 mg/L) was 8.3%, 41.4%, 47.7% and 52.7% for various dosages. In the CCl4 induced liver free radical injury system, the inhibitory rate of the same dosage of TP and Vit C was 45.2%, 42.8% respectively. CONCLUSION: TP (0.3 ~ 8.1 mg/L) and Vit C (9 ~ 81 mg/L) had inhibited lipid peroxidation induced by FeSO4-cysteine in isolated human plasma significantly, and the inhibitory effects of TP was superior to that of Vit C at the same dosages. The same dosage of TP and Vit C had remarkable inhibitory effects on the CCl4 induced liver free radical injury, but there was no significant difference between the two groups.

Animals↗
PubMed2001

Study of the distribution of non-point source pollution in the watershed of the Miyun Reservoir, Beijing, China.

Nitrogen and phosphorus are major nutrients to cause eutrophication to degrade the water quality of the Miyun Reservoir, a very important drinking water source of Beijing in China. These are mainly from non-point sources. The watershed in Miyun County is selected as the study region with a total area of 1400 km2. Four typical monitoring catchments and two experimental units were used to monitor the precipitation, runoff, sediment yield and pollutant loading related to various land uses in the meantime. The results show that the total nutrient loss amount of TN and TP is 898.07 t/a, and 40.70 t/a, respectively, in which nutrient N and P carried by runoff is 91.3% and 77.3%, respectively. There is relatively heavier soil erosion at the northern mountain area whereas the main nutrient loss occurs near the northeast rim of the reservoir. Different land uses influence the loss of non-point source pollutants. The amount of nutrient loss from agricultural land per unit is the highest, nutrient loss from forestry is the second highest and that from grassland is the lowest. However, due to the variability of land use areas, agricultural land contributes the greatest amount of TP and forestry lands the greatest amount of TN.

Agriculture↗
PubMed2001

Genomics and the evolution of aminoacyl-tRNA synthesis.

Translation is the process by which ribosomes direct protein synthesis using the genetic information contained in messenger RNA (mRNA). Transfer RNAs (tRNAs) are charged with an amino acid and brought to the ribosome, where they are paired with the corresponding trinucleotide codon in mRNA. The amino acid is attached to the nascent polypeptide and the ribosome moves on to the next codon. Thus, the sequential pairing of codons in mRNA with tRNA anticodons determines the order of amino acids in a protein. It is therefore imperative for accurate translation that tRNAs are only coupled to amino acids corresponding to the RNA anticodon. This is mostly, but not exclusively, achieved by the direct attachment of the appropriate amino acid to the 3'-end of the corresponding tRNA by the aminoacyl-tRNA synthetases. To ensure the accurate translation of genetic information, the aminoacyl-tRNA synthetases must display an extremely high level of substrate specificity. Despite this highly conserved function, recent studies arising from the analysis of whole genomes have shown a significant degree of evolutionary diversity in aminoacyl-tRNA synthesis. For example, non-canonical routes have been identified for the synthesis of Asn-tRNA, Cys-tRNA, Gln-tRNA and Lys-tRNA. Characterization of non-canonical aminoacyl-tRNA synthesis has revealed an unexpected level of evolutionary divergence and has also provided new insights into the possible precursors of contemporary aminoacyl-tRNA synthetases.

Amino Acyl-tRNA Synthetases↗
PubMed2001

[The adhesion and seeding of NIH3T3 fibroblast on PHB surfaces].

Biodegradable polymers have been widely used in the field of tissue engineering. The adhesive characteristic of polymer surfaces is critical for cell seeding and growth. The adhesion and growth of NIH3T3 fibroblast on poly-beta-hydroxybutrpic acid (PHB) was studied here, and the cell-surface adhesion strength was measured in a shear flow detachment assay. It showed that the critical shear stress for cell detachment was relatively low on PHB, thus cells tend to aggregate and detach from surfaces. On the other hand, cells tend to spread and formed monolayer on poly-lysine coated PHB surface. When the PHB foams scaffolds were coated by poly-lysine, the seeding percentage of cells was also greatly enhanced.

3T3 Cells↗
PubMed2001

[Correlation of coronary angiographic morphology with clinical presentation in unstable angina].

OBJECTIVE: To seek the relation between clinical presentation (Braunwald classification) or electrocardiogram(ECG) and angiographic morphology in patients with unstable angina (UA) and to determine which clinical markers could reliably predict unstable lesions and in-hospital cardiac events. METHODS: 120 hospitalized patients with a clinical diagnosis of UA and an abnormal angiograms(>or=50% diameter stenosis) were selected. Patients were classified according to Braunwald criteria before cardiac catheterization was performed. Coronary arteriograms were reviewed. The lesion morphology (including simple lesion, complex lesion and intracoronary thrombus [ICT]) and in-hospital events (including acute myocardial infarction,cardiac death and prompt revascularization) were observed. Logistic regression was used to evaluate the ability of clinical markers (Braunwald classification or an abnormal ST segment of ECG) to predict unstable lesions and cardiac events. RESULTS: There were more complex lesions in class III group(61%, or 20 of 33) than in class I group(30%, or 13 of 43, P < 0.05) and more ICT in class III group(18%, or 6 of 33) than in class II group (2%, or 1 of 44, P < 0.05). The rate of cardiac events was higher in class III patients (58%, or 19 of 33) than in class I patients (19%, or 8 of 43, P = 0.01 ) or class II patients (25%, or 11 of 44, P < 0.01). Logistic regression analysis demonstrated that an abnormal ST segment of ECG or Braunwald class III were highly predictive of the presence of complex lesion morphology (P < 0.01, OR 4.9; P < 0.01, OR 3.3, respectively). An abnormal ECG was the single predictive clinical indicator of triple vessel disease (P < 0.01, OR 3.9) and cardiac events (P < 0.001, OR 4.8). CONCLUSION: Complex lesion can be best identified by the clinical feature of recent onset refractory angina at rest and abnormal ST segment of ECG in UA patients. Patients with abnormal ST segment represents a high risk of triple vessel disease and cardiac events.

Aged↗
PubMed2001

Protective effects of tea polyphenols on mild hypobaric hypoxia induced pulmonary free radical metabolic disorder in mice.

Objective. To observe the protective effects of natural antioxidant tea polyphenols (TP) on repeated mild hypobaric hypoxia induced pulmonary free radical metabolic disorder in mice. Method. Fourty-two male Kunming mice were randomly divided into three groups (n=14 each): normal control (A); 1500 in mild hypobaric hypoxia (B) and TP protection group (C). The exposure time in hypobaric chamber was 2 h/d, 3d/wk, 8 wk in total. Before hypoxic exposure, TP was orally given to group C at a dose of 100 mg/kg, while distilled water was given to the other two groups. After experiment, the mice were decapitated on the next day and the lung was quickly removed. The malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity and nitric oxide (NO) content were measured. In addition, Cu, Zn-SOD and inducible NO synthase (iNOS) enzymatic contents in lung were were qualitatively examined by immunohistochemical assaying. Result. Compared with the control group, pulmonary MDA concentration and NO content were significantly increased after chronic mild hypobaric hypoxic exposures (P<0.01) but the MDA formation and NO generation in TP protection group were restored to normal. Pulmonary SOD activity in group B tended to increase. Cu, Zn-SOD expression in endothelial cells of bronchioli and iNOS contents in endothelial cells of bronchioli and endothelial cells and smooth muscle cells in pulmonary interstitial vessels were significantly elevated after repeated mild hypobaric hypoxic exposure. These enzymatic abnormal expressions regained to normal after administration of TP. Conclusion. Natural antioxidant TP had protective effects on repeated mild hypobaric hypoxia induced pulmonary free radical metabolic disorder.

Altitude↗
PubMed2001

[Cytokines in experimental cancer cachexia].

OBJECTIVE: To investigate the relationship between cytokine IL-6, IL-1, TNF-alpha and experimental cancer cachexia as well as observe the effect of indomethacin on the cachectic mice. METHODS: T739 mice bearing lung adenocarcinoma LA795 were used as murine tumor cachexia model. In this experiment, serum IL-6, IL-1, TNF-alpha, glucose, protein and triglyceride levels and body weight in different stages of cancer cachexia were monitored. Thirty-two mice were randomized into four groups for comparison, with eight mice in each group: no tumor (NTB) group, tumor without treatment (NT) group, tumor with normal saline (NST) group and tumor with indomethacin (INDT) group. For the last group, intraperitoneal infusion of indothacin 1 microgram/gm was given once every day for six days starting from the 14 th day of tumor implantation. RESULTS: Compared with the NTB group, the NT group showed higher serum of IL-6, IL-1, TNF-alpha and lower total protein, triglyceride and glucose (P < 0.01). After treatment with indomethacin, the INDT mice gave higher serum glucose, protein and lipid levels. Meanwhile, the serum level of IL-6, TNF-alpha and IL-1 in the INDT group was found to be significantly low in comparison with the NST group. CONCLUSION: (1) IL-6, IL-1 and TNF-alpha appear to be involved in experimental cancer cachexia. (2) The positive effects of indomethacin by inhibiting the growth of these cytokines indicate that indomethacin is able to improve the condition of cancer cachexia.

Adenocarcinoma↗
PubMed2001

[A study on the epidemiological characteristics of obesity in Chinese Adults].

OBJECTIVE: To elucidate the epidemiological characteristics of obesity in Chinese adults and to provide scientific basis for public health policy-making, as well as for prevention and control of obesity among Chinese. METHODS: Using the data from diabetes mellitus, epidemiological studies carried out in 11 provinces/autonomous regions/municipalities of China from July 1995 to June 1997, including 42 751 subjects aged 20 - 74 years who had lived in the communities for no less than 5 years. Diagnostic criteria was based on the recommendation from WHO. Epidemiological characteristics of overweight and obesity were analysed. RESULTS: The prevalence rate of overweight and obesity among Chinese adults were 21.51% and 2.92% respectively. The age-standardized prevalence rates of overweight and obesity standardized by Chinese population aged 20 - 74 years were 18.28% and 2.48% respectively in 1990, when standardized by the standard population of world in 1992, the prevalence rates were 18.61% and 2.49% respectively. The prevalence of overweight and obesity in female (21.71% and 3.73% respectively) were significantly higher in male (21.25% and 2.11% respectively), the prevalence rates of obesity in male and in female increased with the increase of age, with the lowest prevalence in 20 year old group (1.23% and 0.96% respectively), the highest were 60 year old group (3.30% and 6.91% respectively). Among 11 provinces, the highest prevalence rates of overweight and obesity were in Beijing (34.75% and 5.14% respectively) of males, and in Shandong (34.56% and 9.36% respectively) of females. The prevalence rates of obesity were significantly higher in northern part of the country (2.64% in males and 4.85% in females) then in the south (1.36% in males and 2.15% in females), as well as significantly higher in urban (2.65% in male and 4.21% in female) than in rural (0.88% in male and 2.80% in female). CONCLUSION: Overweight and obesity had become prevalent in Chinese adults, more seen in the north than in the south, more in females than in males, and in older age than in younger, suggesting an earlier research and practice of prevention and control for overweight and obesity need to be implemented in China.

Adult↗