Biomedical subjects

Tao Li

Publications and source records attributed to Tao Li.

227 records · Page 13Linked to original sources

PubMed2002

Urodynamic study of enhanced continent mechanism using tapered ileum as continent urinary reservoir.

OBJECTIVE: To investigate the effect of extramural support from the pouch and abdominal wall to enhance the continent mechanism of tapered ileum. METHODS: A total of 24 patients underwent a procedure in which an ileal segment was tapered into 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. A urodynamic study of the efferent tubes and pouch was done 1.5 to 3 months and 6 to 24 months postoperatively. RESULTS: One patient died of heart disease 55 days postoperatively, while 22 of the remaining 23 were completely continent day and night. At 1.5 to 3 months, the urodynamic study of the efferent tubes demonstrated that the maximum closure pressure with a full pouch was 46 - 124 cmH(2)O (91.26 +/- 15.71 cmH(2)O) and with an empty pouch was 34 - 84 cmH(2)O (67 +/- 10.60 cmH(2)O). The difference in mean maximum closure pressure in the full and empty pouches was statistically significant (t = -11.78 and P = 0.00001). At 6 to 24 months, a second urodynamic study was performed on 18 cases, demonstrating a reservoir capacity of 420 to 750 ml (481.67 +/- 78.83 ml). Reservoir pressure was 6 to 9 cmH(2)O (7.17 +/- 1.17 cmH(2)O) when the pouch was filled to 50 ml, and 16 to 35 cmH(2)O (24.12 +/- 5.61 cmH(2)O) when it was filled to maximum capacity. There was no contractive wave during the filling in any patient. Maximum closure pressure in the efferent tube was 80 to 194 cm H(2)O (98.89 +/- 26.34 cmH(2)O) when the pouch was filled with saline, and 64 to 128 cmH(2)O (74.78 +/- 14.54 cmH(2)O) when the pouch was empty. The difference in mean maximum closure pressure in the full and empty pouches was statistically significant (t = -7.58 and P = 0.00003). CONCLUSIONS: This study indicates that the continent mechanism of tapered ileum may be greatly enhanced by extramural support from the abdominal and pouch walls.

Adult↗

PubMed2002

[Comparative analysis of diuretic activities of human ANP gene injected intramuscularly and intravenously in adriamycin-induced nephrotic rats].

In order to explore the feasibility of gene therapy strategy based on the human atrial natriuretic peptide (hANP) gene delivery for the treatment of nephropathy and compare the diuretic activities of the hANP gene injected intramuscularly(i.m.) and intravenously(i.v.), the naked retroviral vector DNA harboring the hANP cDNA under the control of retroviral 5' long terminal repeat at a dose of 5 mg/kg body weight was injected i.m. or i.v. into the nephrotic model rats induced with adriamycin(ADR) injected i.v. at a dose of 7.5 mg/kg body weight. A single injection of the hANP gene resulted in a marked elevation in plasma level of hANP 5 days after gene delivery and a significant increase in the ratio of urine volume to body weight and the diuretic effect continued for more than 15 days. In addition, there was a significant rise in the body weight of treatment groups as compared with that of negative control group and no difference in the concentrations of electrolytes in urine between groups. There was no significant differences in total effects resulted from the two routes of gene delivery and the way of gene delivery through the skeletal muscle is simpler and easier. These results suggest that somatic gene delivery of the hANP gene could enhance the renal functions in nephrotic rats significantly and would be a potential strategy for the treatment of renal disorders.

Animals↗

PubMed2002

[Determination and contrastion of alkaloids and saponins in Bulbus Fritillariae Cirrhosae and in other beimus].

OBJECTIVE: To establish quality standard of Bulbus Fritillariae Cirrhosae by determining and comparing alkaloids and saponins in various Beimus. METHOD: Alkaloids in beimus were determined with two-phase titration and saponins in Beimus were determined with weight method. RESULT AND CONCLUSION: The contents of alkaloids and saponins in 4 species of Bulbus Fritillariae Cirrhosae (each specie including 3 samples) Zhe Beimu, Yi Beimu and Pin Beimu (each specie including 2 samples) were determined.

Alkaloids↗

PubMed2002

[Genetic polymorphism of 9 STR loci in Han nation population in Shandong Province].

OBJECTIVE: To study genetic polymorphism of 9 STR loci in Han nation population in Shangdong Province. METHODS: We investigated 100 unrelated individuals of Han nation population in Shandong Province and studied their genetic distribution of 9 STR loci and Amelogenin locus. Primers of 10 loci were labeled with the NHS-ester fluorescent dye 5-FAM (blue), Joe (green) or NED (yellow). The data of Han nation population were generated by multiple amplification and subjected to GeneScan, genotype and genetic distribution analysis. RESULTS: 83 alleles and 220 genotypes were observed, with the corresponding frequency of 0.0050-0.4050 and 0.0100-0.2100. The average of heterozygosity was 0.7778, the accumulated discrimination power was 0.9999. The accumulated probability of exclusion paternity was 0.9999. The polymorphism information content was 0.5823-0.8396. CONCLUSIONS: Chi-Square test indicated that the distribution of genotypes agreed with Hardy-Weinberg equilibrium.

Alleles↗

PubMed2002

[Effects of deltamethrin on intracellular free Ca2+ concentration and apoptosis in rat neural cells].

OBJECTIVE: To study the effects of deltamethrin on intracellular free Ca2+ concentration and apoptosis in rat neural cells. METHODS: Wister rats were randomly divided into 4 groups(3 treated groups and 1 control). Intracellular free Ca2+ concentration in rat neural cells was measured by using the fluorescent Ca2+ indicator Fura-2/AM. Apopotic rate of neural cells was measured by using FACS420 Flow Cytometer. RESULTS: Intracellular free Ca2+ concentration at 5 h after deltamethrin exposure [hippocampus: (389.94 +/- 43.64) nmol/L, cerebral cortex: (449.33 +/- 23.23) nmol/L], at 24 h[hippocampus: (340.47 +/- 32.36) nmol/L, cerebral cortex: (311.62 +/- 25.48) nmol/L] and at 48 h[hippocampus: (287.13 +/- 24.29) nmol/L, cerebral cortex: (346.55 +/- 36.87) nmol/L] were all higher than those of the control group[hippocampus: (203.24 +/- 18.53) nmol/L, cerebral cortex: (226.85 +/- 14.81) nmol/L, P < 0.01]; Apoptotic rate in neural cells 24 h and 48 h later [hippocampus: (8.45 +/- 1.02)%, (9.44 +/- 1.14)%, cerebral cortex: (7.90 +/- 0.49)%, (8.01 +/- 0.87)%] were also higher than those of the control group[hippocampus: (2.97 +/- 0.36)%, cerebral cortex: (3.50 +/- 0.48)%, P < 0.01)] and increased with time prolonged. CONCLUSION: Exposure to high dose of deltamethrin would interfere with intracellular free Ca2+ concentration and apoptotic rate in rat neural cells, suggesting that there may be certain relation between them.

Animals↗

PubMed2001

Electrical Conductivity of Water/Sodium Bis(2-ethylhexyl) Sulfosuccinate/n-Heptane and Water/Sodium Bis(2-ethylhexyl) Phosphate/n-Heptane Systems: The Influences of Water Content, Bis(2-ethylhexyl) Phosphoric Acid, and Temperature.

Conductance behaviors of reverse micelles/microemulsions have been investigated by means of electrical conductometry, with em-phasis on the influences of water content, bis(2-ethylhexyl) phos-phoric acid (HDEHP) content, and temperature. Two systems were prepared and studied, i.e., sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in n-heptane (H(2)O/AOT/n-heptane) and sodium bis(2-ethylhexyl) phosphate (NaDEHP) in n-heptane (H(2)O/NaDEHP/ n-heptane). The conductance behaviors of AOT+HDEHP and NaDEHP+HDEHP systems are dependent upon water content (W(0), expressed as the molar ratio of solubilized water and surfactant(s)), HDEHP content, and temperature. With an increase of water content, the conductivity-W(0) curves of the AOT+HDEHP system show maximum conductivity and no percolation conductance, different from that of the AOT system. The conductivity of the NaDEHP+HDEHP system varies with the NaDEHP to HDEHP ratio. For the systems with the NaDEHP to HDEHP ratios of 80 : 20 and 70 : 30, both maximum conductivity and percolation phenomenon can be observed, while for the system with the NaDEHP to HDEHP ratio of 90 : 10, neither maximum conductance nor percolation conductance occurs. With varying temperature, markedly different conductance behaviors were observed in AOT+HDEHP and NaDEHP+HDEHP systems. Percolation conductance occurs in the AOT+HDEHP system and the onset temperature for percolation conductance decreases with increasing water content and/or HDEHP content. In the H(2)O/(NaDEHP, HDEHP)/n-heptane system, however, the conductivity decreases markedly with increasing temperature until a minimum, followed by a slow recovery of the conductivity. These phenomena could be attributed to the different aggregation states of the surfactants and the different transition mechanisms of charge carriers in respective systems at different water contents, HDEHP contents, and temperatures. Copyright 2001 Academic Press.

Journal Article↗

PubMed2000

The carboxylic acid reduction pathway in Nocardia. Purification and characterization of the aldehyde reductase.

Whole cultures of Nocardia sp. NRRL 5646 reduce carboxylic acids, first to aldehydes, then to alcohols and subsequently to the corresponding acetyl esters. This work describes an NADPH-dependent reductase responsible for catalyzing the reduction of aldehyde intermediates, which was purified 3240-fold by a combination of Mono-Q, hydroxyapatite, and ADP-agarose chromatographies. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified enzyme ran as a single band of 47 kDa. A native molecular mass estimated at 101 kDa indicated that the enzyme was a homodimer in the native, active state. Edman degradation indicated a unique N-terminal sequence as NH(2)-X-X-Ala-Ala-Ala-Tyr-Ala-Val-Pro-Ala-Pro-Asp-Gly-Cys-Phe-Glu-Lys-Val-Thr-Ile-Glu-Arg-Arg-Glu-Leu-Gly. The enzyme catalyzed reductions of many aryl- and alkyl-aldehyde substrates. Reactions were most favorable in the direction of aldehyde reduction to alcohols.

Journal Article↗

PubMed2000

[Promotion of Thrombopoiesis by rhIL-11 in Normal and Myelosuppressed Mice]

Hematological effects of rhIL-11 on normal and myelosuppressed male BALB/c mice were observed. Mice were subcutaneously injected with rhIL-11 for 7 consecutive days, at the dose of 200 or 400 micro g/kg per day, peripheral blood platelet counts were moderately elevated on 5 days after administration and returned to base level within 4 days after discontinuation of injection. In myelosuppressed mice, treatment with rhIL-11 significantly ameliorated the degree of thrombocytopenia, the recovery of thrombocytopenia was also significantly accelerated at the dose range of 100 - 400 micro g/kg per day, and blood platelet counts reached pre-irradiated level after 13 - 15 days of treatment. The magnitudes of platelet count elevation were similar among groups of 100, 200 and 400 micro g/kg per day, although recovery appeared earlier in group of 400 micro g/kg per day. Significant increases in CFU-Meg were observed both in normal and myelosuppressed mice. Our results suggest that rhIL-11 promotes the increase of peripheral blood platelets both in normal and myelosuppressed mice, and can be used as a potential therapeutic agent for thrombocytopenia induced by chemotherapy.

Journal Article↗

PubMed2000

[Therapeutic Effects of rhIL-11 on Carboplatin-Induced Thrombocytopenia in Monkeys]

A model of myelosuppression with thrombocytopenia was produced in monkey by i.v. administration of carboplatin to the evaluate effects of rhIL-11 treatment in monkeys. Following myelosuppression, rhIL-11 was subcutaneously injected for 19 consecutive days at the dose of 50 or 100 micro g/kg. In myelosuppressed monkeys treated with rhIL-11, peripheral blood platelet started to drop at the day 8 after the administration of carboplatin, and reaching the nadir between the day 12 - 14, the decrease in blood platelet was less severe compared with untreated monkeys; peripheral blood platelet began to recovery on day 11 - 13 (D14 - D16) after rhIL-11 treatment, and reached or surpassed the baseline value before carboplatin administration after 13 - 15 days rhIL-11 treatment. Blood platelet counts remained high level after discontinuation of rhIL-11 administration and returned to baseline after 4 days. The results demonstrated that rhIL-11 has a significant thrombopoietic activity, it can reduce the severity of thrombocytopenia as well as shorten the duration of thrombocytopenia caused by myeloablastive agents, and is likely to become an effective agent against thrombocytopenia induced by chemotherapy.

Journal Article↗

PubMedDate not supplied

T2-weighted echo planar MR imaging of the abdomen: optimization of imaging parameters.

Echo planar imaging (EPI) is an ultra-fast magnetic resonance (MR) imaging method that provides strong T2-weighted contrast, which is important for the detection and characterization of various abdominal abnormalities. However, EPI may be associated with significant artifacts. The prominence of these artifacts, as well as overall image quality, is dramatically impacted by selection of imaging parameters. The purpose of this study is to demonstrate the effects of controlled alterations in operator-defined imaging parameters on image quality in breath-hold abdominal T2-weighted EPI. An understanding of these effects facilitates optimizing parameter selection for acquisition of abdominal EPI images.

Abdomen↗

PubMedDate not supplied

Using uncorrelated discriminant analysis for tissue classification with gene expression data.

The classification of tissue samples based on gene expression data is an important problem in medical diagnosis of diseases such as cancer. In gene expression data, the number of genes is usually very high (in the thousands) compared to the number of data samples (in the tens or low hundreds); that is, the data dimension is large compared to the number of data points (such data is said to be undersampled). To cope with performance and accuracy problems associated with high dimensionality, it is commonplace to apply a preprocessing step that transforms the data to a space of significantly lower dimension with limited loss of the information present in the original data. Linear Discriminant Analysis (LDA) is a well-known technique for dimension reduction and feature extraction, but it is not applicable for undersampled data due to singularity problems associated with the matrices in the underlying representation. This paper presents a dimension reduction and feature extraction scheme, called Uncorrelated Linear Discriminant Analysis (ULDA), for undersampled problems and illustrates its utility on gene expression data. ULDA employs the Generalized Singular Value Decomposition method to handle undersampled data and the features that it produces in the transformed space are uncorrelated, which makes it attractive for gene expression data. The properties of ULDA are established rigorously and extensive experimental results on gene expression data are presented to illustrate its effectiveness in classifying tissue samples. These results provide a comparative study of various state-of-the-art classification methods on well-known gene expression data sets.

Algorithms↗