Biomedical subjects

T Wang

Publications and source records attributed to T Wang.

At least 163 records · Page 9Linked to original sources

PubMed2001

[Research advances of multidimensional reconstruction of ultrasonic heart images].

The methods, present research situation, existing problems, and application foreground of multidimensional reconstruction of ultrasonic heart images are discussed in the present paper. According to the procedure of multidimensional reconstruction of ultrasonic heart images, the discussions are presented in respect to image acquisition, processing, and display. Based on the present situation and existing problems, the future development and application foreground are proposed.

Echocardiography, Three-Dimensional↗

PubMed2001

[Review of filtering algorithms for medical ultrasonic images].

Several kinds of filters for medical ultrasonic images, such as multidimensional filter, adaptive weighted filter (for example, adaptive weighted median filter), adaptive window selecting filter (for example, homogeneous region growing mean filter and adaptive speckle suppression filter) and two-step filter, are introduced. The existing problems and the progress trend are also discussed. Some application instances for medical ultrasonic images of the filters discussed and the performance of the filters presented are based on the present authors' practice.

Algorithms↗

PubMed2001

[The method of instantaneous pulse detection based on hybrid wavelet transform].

In this paper, we discuss the relation between matched filter and wavelet transform(WT), and point out that wavelet transform is just the matched filter with changeable detection template. According to this idea, the method of signal detection based on hybrid wavelet transform (HWT) is proposed. HWT in this paper means that in WT decomposition and reconstruction, we use two different mother wavelets. One is used as a changeable template for the pulses detection and the other is used for the characteristic enhancement of detected pulse. This method has been applied to the interference pulse detection in EEG signal. The experiment result shows that HWT has the good property for instantaneous signal detection.

Algorithms↗

PubMed2001

[Anti-oxidation effect of water extract of Flos chrysanthemi on heart and brain in vivo and in vitro].

This paper reported the effect of water extract of Flos Chrysanthemi on lipid per-oxidation (LPO) of heart and cerebral homogenate from rats incubated in 37 +/- 0.5 degrees C, of heart and cerebral homogenate from mice induced by .OH, of heart and cerebral mitochondria member induced by .OH, which was compared with Radix Salviae Miltiorrhizae. The results showed that the inhibition effect of water extract of Flos Chrysanthemi on above-mentioned LPO was equal to Radix Salviae Miltiorrhizae. It was concluded that water extract of Flos Chrysanthemi could restrain the produce of free radicals and LPO induced by free radicals.

Animals↗

PubMed2001

Pharmacologic or genetic manipulation of glutathione S-transferase P1-1 (GSTpi) influences cell proliferation pathways.

Glutathione S-transferase P1-1 (GSTpi) is an abundant and ubiquitously expressed protein in normal and malignant mammalian tissues and possesses catalytic and ligand binding properties. Our present data suggest that the protein contributes to the regulation of cell proliferation. Mouse embryo fibroblasts (MEFs) isolated from mice with a GSTP1-1 [glutathione S-transferase P1-1 (isozyme in nonhepatic tissue)] null genotype (GSTpi(-/-)) doubled their population in 26.2 h versus 33.6 h for the wild type (GSTpi(+/+)). Retroviral transfection of GSTP1-1 into GSTpi(-/-) MEF cells slowed the doubling time to 30.4 h. Both early passage and immortalized MEF cells from GSTpi(-/-) animals expressed significantly elevated activity of extracellular signal-regulated kinases ERK1/ERK2, kinases linked to cell proliferation pathways. In vivo, GSTpi(-/-) mice had higher basal levels of circulating white blood cells compared with GSTpi(+/+). Administration of a peptidomimetic inhibitor of GSTP1-1, TLK199, (gamma-glutamyl-S-(benzyl)cysteinyl-R-phenyl glycine diethyl ester), stimulated both lymphocyte production and bone marrow progenitor (colony-forming unit-granulocyte macrophage) proliferation, but only in GSTpi(+/+) and not in GSTpi(-/-) animals. Selection of a resistant clone of an HL60 tumor cell line through chronic exposure to TLK199 resulted in cells with elevated activities of c-Jun NH2 terminal kinase (JNK1) and ERK1/ERK2, and allowed the cells to proliferate under stress conditions that induced high levels of apoptosis in the wild type cells. The in vitro and in vivo data are consistent with the principle that GSTP1-1 influences cell proliferation.

Animals↗

PubMed2001

Dendritic growth induced by BMP-7 requires Smad1 and proteasome activity.

Bone morphogenetic proteins (BMPs) induce dendritic growth in cultured sympathetic neurons; however, the signaling pathways that mediate this dendrite-promoting activity have not been previously characterized. Here we report studies of the signaling events that regulate the growth of these afferent processes. We find that Smad1 is expressed in sympathetic neurons and that BMPs rapidly induce its phosphorylation and translocation from the cytoplasm to the nucleus. Furthermore, a dominant negative form of Smad1 inhibits BMP-7-induced dendritic growth, suggesting a requirement for Smad1 activation in this biological activity of BMP-7. A physical interaction between Smad1 and components involved in the proteasome-mediated degradation system was detected with a yeast two-hybrid screen, thereby prompting an examination of the effects of proteasome inhibitors on dendritic growth. Lactacystin and ALLN (N-acetyl-Leu-Leu-norleucinal) selectively blocked BMP-7-induced dendritic growth without adversely affecting either cell viability or axonal growth. Moreover, studies of transfected P19 cells suggest that the proteasome inhibitors directly block the effects of Smad1 on the transcriptional activity of the Tlx-2 promoter. These data indicate that BMP-induced dendritic growth requires Smad1 activation and involves proteasome-mediated degradation events.

Acetylcysteine↗

PubMed2001

[Auto-detection of contour in echocardiographic images based on active contour model].

Contour detection is one of the most difficult problems in the multi-dimensional reconstruction of echocardiographic images. A method based on active contour model is presented in the present paper to solve this problem. First, according to the characteristic of the ultrasonic medical images, an adaptive weighted median filter is used to suppress speckle noise and an adaptive threshold value is selected to get binary image. Then, mathematical morphological treatment is utilized to get the initial contour. At last, active contour model is employed to revise the initial contour and get the accurate final contour. Experiments with real and interpolated ultrasonic images are presented. The results show the effectiveness of this method. This method has practical use in the multi-dimensional reconstruction of ultrasonic medical images.

Algorithms↗

PubMed2001

[Cloning of the mouse Doc-1R gene by genomic walking].

OBJECTIVE: To obtain the genomic sequences of the mouse Doc-1R gene. METHODS: Gene-specific primers were designed and synthesized based on the cDNA sequences of the mouse Doc-1R gene. With the use of genomic walking strategy, the mouse genomic walking library was amplified by the polymerase chain reaction(PCR). Mouse genomic library constructed with a special adaptor was utilized as a template to amplify the desired fragment by nested PCR. RESULTS: A desired fragment of 1.5 kb was obtained. Sequence analysis of the desired fragment confirmed that the genomic cloning of the Doc-1R gene was successful. This gene contains four exons and three introns. All of the splice donor/acceptor site sequences are in accordance with the consensus 'GT-AG' rule. CONCLUSION: The genomic walking strategy is simple, efficient and reliable; it is an ideal method of cloning genomic fragments.

Animals↗

PubMed2001

Loss of phospholipids asymmetry in red blood cells contributes to anemia in uremic patients.

Anemia is common in dialysis patients. Change in phospholipids asymmetry in red blood cells (RBCs) may affect the removal of RBCs from the circulation and thus shorten the lifespan of RBCs. In the present study, we investigated phospholipids asymmetry in RBCs in uremic patients and its relationship with anemia. We studied 34 continuous ambulatory peritoneal dialysis (CAPD) patients (age: 51 +/- 15 years), 73 hemodialysis (HD) patients (age: 48 +/- 12 years), 8 pre-dialysis renal-failure patients (age: 42 +/- 21 years), and 16 healthy controls (age: 32 +/- 9 years). All patients were clinically stable. Phospholipids asymmetry as measured by phosphatidylserine exposure was determined by a flow-cytometric annexin V-binding assay. Hemoglobin levels were 93 +/- 20 g/L, 83 +/- 17 g/L, 78 +/- 21 g/L, and 145.8 +/- 12.5 g/L for CAPD patients, pre-dialysis patients, HD patients, and healthy controls respectively. Phosphatidylserine exposure in RBCs was significantly higher in uremic patients as compared with healthy controls, especially in HD patients--whose values were significantly higher than values seen in CAPD patients and pre-dialysis patients. No significant difference was seen in RBC phosphatidylserine exposure between pre-dialysis patients and CAPD patients. Cells positive for annexin V binding were 1.58%, 1.40%, 2.11%, and 0.71% for CAPD patients, pre-dialysis patients, HD patients, and healthy controls respectively. Significant reverse correlations were seen between annexin V and hemoglobin (r = -0.381, p < 0.001), and between annexin V and hematocrit (r = -0.355, p < 0.001). Our results suggest that (1) anemia is common in our uremic patients, especially in HD patients; and (2) anemia in uremic patients may be partly related to the loss of phospholipids asymmetry in RBCs.

Adult↗

PubMed2001

Methods to improve the preservation of peritoneal tissues.

Peritoneal mesothelial cells are easily detached during conventional tissue processing, which may result in artifacts in peritoneal tissue examination. Therefore, in the present study, we investigated several methods to improve the preservation of the anterior parietal peritoneal tissues. Peritoneal tissue from the anterior abdominal wall was taken from each of 5 rats killed for the experiment. Tissue samples were immediately treated by one of these methods: (1) fixed with 10% formaldehyde; (2) fixed with Bouin's solution; (3) fixed with Helly's solution. After fixation, the samples were dehydrated with one of (a) ethanol, 1 hour in each step; (b) ethanol, 15 minutes in each step; or (c) tertiarybutyl alcohol. Five sections were taken from each tissue and stained with hematoxylin and eosin. The quality of tissue fixation was evaluated by image analysis. Peritoneal mesothelial cells were well preserved after fixation with Helly's solution or Bouin's solution. With 10% formaldehyde, about 40% of the mesothelial cells were lost. Dehydration with ethanol--especially long-duration dehydration--increased the loss. However, dehydration with tertiarybutyl alcohol avoided the increased loss of mesothelial cells. The submesothelial extracellular matrix was well preserved with Bouin's solution, but not with the other fixatives. Our results suggest that fixation with formaldehyde and dehydration with ethanol results in significant loss of peritoneal mesothelial cells and submesothelial extracellular matrix in peritoneal tissues. Fixation with Bouin's solution and dehydration with tertiary-butyl alcohol may be a better method of preserving peritoneal tissue.

Animals↗

PubMed2001

Influence of beta1-adrenoceptor blockade on the gene expression of adenylate cyclase subtypes and beta-adrenoceptor kinase in human atrium.

There is accumulating evidence of cross-regulation between stimulatory G-protein (G(s))-coupled receptors in human atrium. Chronic beta(1)-adrenoceptor antagonist treatment can sensitize beta(2)-adrenoreceptors, 5-HT(4) receptors, histamine H(2) receptors and possibly beta(4)-adrenoreceptors. To investigate the mechanism of such cross-talk between G(s)-coupled receptors, we have measured the mRNA expression of the cardiac adenylate cyclases (types IV, V, VI and VII) and of beta-adrenoceptor kinase 1 in human atria using TaqMan quantitative PCR, and compared expression between patients chronically receiving a beta(1)-adrenoceptor antagonist and non-treated patients. The results showed no difference in gene expression between the two groups of patients; however, significant positive correlations of gene expression between adenylate cyclase subtypes were found. We conclude that beta(1)-adrenoceptor antagonists do not change the absolute levels of gene expression of adenylate cyclase subtypes in human atrium. The co-ordinate regulation among adenylate cyclase subtypes and the influence of beta(1)-adrenoceptor antagonists need to be investigated further.

Adenylyl Cyclases↗

PubMed2001

[Effect of simulated weightlessness on the apoptosis of thymus cells in tail-suspended mice].

OBJECTIVE: To investigate the effect of simulated weightlessness on apoptosis of thymus cells in mice. METHOD: Tail-suspended mice were used as an animal model of simulated weightlessness; chromosome breakage was measured by PI staining, and changes of cell membrane were determined by Annexin-V analysis. RESULT: As compared with the control, there was no obvious chromosome breakage; the total number of apoptotic cells and number of early apoptotic cells increased in 1 d suspended group; the number of early apoptotic cells increased significantly and the total number of apoptotic cells increased very significantly in 2d suspended groups. CONCLUSION: These results suggested that simulated weightlessness could promote apoptosis of thymus cells.

Animals↗

PubMed2001

[Effects of simulated weightlessness on T cell subpopulations and activity of IL-2 and IL-6 in mice].

OBJECTIVE: To observe the effects of simulated weightlessness on the immunogenic activities in mice. METHOD: T cell subpopulations and the activity of IL-2 and IL-6 were observed in mice after exposure to head-down (-30 degrees) tail suspension for 3 d and 7 d. RESULT: The activity of IL-2 and IL-6 in mice showed no change after simulated weightlessness for 3 d compared with the control group. But after simulated weightlessness for 7 d, CD3+ and CD4+ were markedly reduced (both P< 0.01) and CD8+ and CD4+/CD8+ also tended to decrease; the activity of IL-2 was significantly decreased, while the activity of IL-6 tended to increase. CONCLUSION: Simulated weightlessness for 7 d had significant effects on T cell subpopulations and the activity of certain cytokines in mice.

Animals↗

PubMed2001

[Effects of nitric oxide (NO) on the cardiac function in severely scalded rats].

OBJECTIVE: To investigate the effects of NO on the cardiac function in severely scalded rats and to elucidate its mechanism. METHODS: Ninety Sprague-Dawley (SD) rats inflicted with 30% TBSA III degree scalding were employed as the model and divided randomly into five groups, i.e. burn (B), shamburn (SB), L-arginine (L-Arg), N-nitroso-L-argininemethylester (L-NAME) and L-Arg + L-NAME groups. Cardiac functional indices, myocardial content of malondialdehyde (MDA) and myocardial Ca (calcium) transport were examined in the rats of all the groups, respectively. RESULTS: Compared to those in B group, the mean arterial pressure (MAP), left ventricular summit pressure (LVSP), the +/- dp/dt max in left ventricle pressure and the cardiac Lo in L-NAME group increased obviously. While those in L-Arg group decreased significantly but those in L-Arg + L-NAME group exhibited no remarkable change. The MDA content in L-NAME group was evidently lower than that in B group, while the calcium transport index of sarcoplasmic reticulum in L-NAME group increased obviously. CONCLUSION: Nitric oxide, massively produced postburn, exerted inhibitory effects on cardiac function by means of the cytotoxicity of its owns and other free radicals, which might be closely related to the decrease of its calcium transport function of sarcoplasmic reticulum.

Animals↗

PubMed2001

[Differences of nitric oxide synthase expression and activity between splanchnic arterial and venous vessels of cirrhotic rats].

OBJECTIVE: To understand the implication of differences of nitric oxide synthase (NOS) expression and activity between splanchnic arterial and venous vessels in the pathogenesis of portal hypertension. METHODS: Cirrhosis was induced in 100 Wistar rats by subcutaneously administration of carbon tetrachloride. NOS localization, activity and gene expression in the mesenteric artery and the portal vein vessels of both cirrhotic and normal rats were investigated by immunohistochemistry, chemoluminescence and reverse transcription-polymerase chain reaction, respectively. RESULTS: There was inducible NOS enzyme isoform in al1 layers of splanchnic vessels of cirrhotic rats, whereas endothelial NOS isoform largely in vascular endothelia. NOS activity and its mRNA expression all were significantly increased in cirrhotic rats when compared with normal rats (P<0.05 or 0.01).Moreover, the activities of general and constitutive NOS and the expression of endothelial NOS mRNA in cirrhotic rats were significantly higher in the mesenteric artery than in the portal vein (P<0.01). CONCLUSIONS: Enhanced expression and activity of endothelial NOS enzyme isoform may be mainly responsible for increased NO production of splanchnic vessels in cirrhotic rats, and the differences of NOS expression and activity between the mesenteric artery and the portal vein vessels may be one of the pathogeneses of portal hypertension in which NO might be involved.

Animals↗

PubMed2001

[Suppression subtractive hybridization in the cloning of gene fragments in relation to lung cancer metastasis].

OBJECTIVE: In order to provide important information about early diagnosis and treatment of tumor metastasis, a study on the biological regulation of metastasis at the molecular level was carried out by isolating and identifying human metastatic suppressor gene or related DNA sequences from a pair of cell clones with different metastatic phenotypes. METHODS: Suppression subtractive hybridization technique (SSH), gene cloning and analysis by bioinformatics were applied to this study. Two cell clones of pulmonary giant cell carcinoma originating from the same patient were used. The PLA-801C cell clone which shows lower metastatic potentiality was used as tester and the PLA-801D as a driver. RESULTS: Five cDNA clones so obtained were expressed on much higher levels in the poorly metastatic cancer cell clone than the highly metastatic one. Homology analysis of all five cDNA fragments by BLASTN through GenBank showed high homology with the known human genes. CONCLUSION: Through using SSH, we have identified five cDNA fragments which are expressed at much higher levels in the poorly metastatic cancer cell clone than the highly metastatic variety. Therefore, it is supposed that they might play an important role in the suppression of metastatic tumor cells and may very well have potential application in the diagnosis and treatment of metastasis.

Base Sequence↗

PubMed2001

West Nile virus envelope protein: role in diagnosis and immunity.

The role of antibodies to the West Nile virus envelope (E) protein in serodiagnosis and protection was examined. The E protein was expressed and purified in recombinant form. Antibodies to the E protein were detected in patients with West Nile virus infection. Passive immunization with rabbit anti-E protein sera also partially protected mice from challenge with West Nile virus. The humoral response to the West Nile virus E protein is therefore useful as an aid in the diagnosis and may also play a role in immunity to infection.

Animals↗

PubMed2001

[Pharmacokinetics of adriamycin by bronchial artery infusion for non-small cell bronchogenic carcinoma].

OBJECTIVE: This pharmacokinetic study was conducted to determine the plasma concentration of adriamycin after bronchial artery infusion (BAI), and to compare it with the conventional chemotherapy. METHODS: Twenty-four healthy rabbits were divided into 4 groups with 6 animals in each. Comparison of the parameters was investigated in pharmacokinetics after ear-lobe venous injection of ADM (Group 1) and in combination with DDP or/and MMC (Groups 2, 3, 4). Intracardial blood samples were obtained according to the fixed time and quantity. Dose for each drug was: ADM 2 mg/kg, DDP 4 mg/kg, and MMC 2 mg/kg. Seventeen patients suffering from primary non-small cell bronchogenic carcinoma, the central type, confirmed by pathology and cytology comprised the clinical group, all of whom showing single blood supply by angiography, was given bronchial artery infusion. According to the scheduled time and quantity, we sampled blood species via indwelling catheter in the right median cubital vein after the bronchial artery infusion. Dose of the each drug was: ADM 40 mg/m2, DDP 80 mg/m2, and MMC 14 mg/m2. Plasma concentration of ADM was determined by fluorophotometry. Since the cessation of chemotherapy, blood samples were taken from the thoracic aorta via indwelling catheter at 0, 1, 3, 5, 10, 15 and 20 minutes; venous blood samples were taken from the right cubital vein through the indwelling catheter at 0, 5, 10, 15, 20 minutes, and also at 0.5, 1, 2, 4, 8, 12, 24 and 48 hours altogether at 20 time-spots with 2 ml per sample. RESULTS: The calibration curve was linear from 10 ng/ml to 1,000 ng/ml with r = 0.9983. The relationship standard difference (RSD) within a day was lowered to 2%, and the RSD between days was lowered to 3%. The formula of concentration-time curve for ADM was C microgram/ml = 129.44e(-13.36t) + 0.25e(-0.072t) in animal Group 1, and C microgram/ml = 370.93e(-23.43t) + 0.04e(-0.09t) in Group 4 animal. The formula in the clinical group was C microgram/ml(artery) = 448.61e(-66.62t) + 16.35e(-8.13t)(artery) and C microgram/ml(vein) = 15.69e(-21.66t) + 0.07e(-0.038t)(vein). CONCLUSION: Compared with the conventional chemotherapy in pharmacokinetics, bronchial artery infusion can be used as a treatment for non-small cell bronchogenic carcinoma with more effectiveness and less side effects.

Animals↗