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Biomedical subjects

Tao Zhou

Publications and source records attributed to Tao Zhou.

At least 55 records · Page 3Linked to original sources
PubMed2005

Power law distribution of wealth in population based on a modified Equíluz-Zimmermann model.

We propose a money-based model for the power law distribution (PLD) of wealth in an economically interacting population. It is introduced as a modification of the Equíluz and Zimmermann (EZ) model for crowding and information transmission in financial markets. Still, it must be stressed that in the EZ model a PLD without exponential correction is obtained only for a particular parameter, while our pattern will give the exact PLD within a wide range. The PLD exponent depends on the model parameters in a non-trivial way and is exactly calculated in this paper. The numerical results are in excellent agreement with the analytic prediction, and also comparable with empirical data of wealth distribution.

Journal Article↗
PubMed2005

In vivo identification of the interaction site of ErbB2 extracellular domain with its autoinhibitor.

Direct interference with the transforming potential of ErbB2 has become a subject of great interest. Disruption of critical ErbB2 ectodomain interactions may lead to novel therapeutic approaches for the treatment of various tumors. The ErbB receptor signaling can be inhibited by rationally designed peptide mimetics based on the subdomains of ErbB ectodomain. The mimetics can bind to the ErbB receptor specifically and block inter-receptor interactions, resulting in the growth inhibition of ErbB2-overexpressing cells in vitro. In this study, three-dimensional structure of herstatin, an autoinhibitor of ErbB2 and ErbB2 ectodomain complex was constructed by computer-aided molecular modeling. The binding site on ErbB2 ectodomain for herstatin was determined at S1 domain. The mutants of ErbB2 ectodomain were constructed. The interactions of ErbB2 ectodomain and its mutants with herstatin were analyzed for the first time in living cells that coexpressed herstatin and ErbB2 ectodomain or the mutants. The S1 domain in ErbB2 ectodomain was verified as the interaction site with herstatin by immunoprecipitation, confocal microscopy, and fluorescence resonance energy transfer (FRET). The binding region of herstatin on ErbB2 ectodomain might be a potential target region for the drug design.

Amino Acid Sequence↗
PubMed2005

Structural characterization of chelator-terminated dendrimers and their synthetic intermediates by mass spectrometry.

Herein, we report the structural analysis of a novel family of iron-chelating dendrimers and their synthetic intermediates utilizing matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and electrospray ionization ion trap (ESI IT) MS. These dendrimers share a benzene tricarbonyl core moiety attached to three tripodal branching units, each linking to three terminal groups, ranging from carboxyl, catechol and 3-hydroxy-6-methyl-pyran-4-one moieties and their protected analogs. In order to monitor the progression of dendrimer synthesis, all intermediates and final products were mass analyzed by conventional MALDI-TOF MS with and without alkali metal spiking. For structural characterization, interpretable post-source decay (PSD) and electrospray ionization ion trap MS/MS spectra were obtained from proton, sodium and potassium adducts of the dendrimers. One major route of dendrimer fragmentation was at or adjacent to the amide bonds either of the terminal chelating groups or near the core moiety. Fragmentation in the latter case was primarily at the N-terminal side of the amide bond and was directed by the proximity of a tertiary carbon of the branching unit. Furthermore, it was found that terminal ester, ether and amide linkages to the protecting and chelating groups could be sequentially broken in a single MS/MS spectrum through multiple cleavages resulting in product ions of decreasing intensity. Moreover, such cleavages could also be induced in a stepwise manner in a multistage ion trap MS(n) experiment.

Chelating Agents↗
PubMed2005

Absolute isotopic composition and atomic weight of neodymium using thermal ionization mass spectrometry.

Synthetic mixtures prepared gravimetrically from highly enriched isotopes of neodymium in the form of oxides of well-defined purity were used to calibrate a thermal ionization mass spectrometer. A new error analysis was applied to calculate the final uncertainty of the atomic weight value. Measurements on natural neodymium samples yielded an absolute isotopic composition of 27.153(19) atomic percent (at.%) 142Nd, 12.173(18) at.% 143Nd, 23.798(12) at.% 144Nd, 8.293(7) at.% 145Nd, 17.189(17) at.% 146Nd, 5.756(8) at.% 148Nd, and 5.638(9) at.% 150Nd, and the atomic weight of neodymium as 144.2415(13), with uncertainties given on the basis of 95% confidence limits. No isotopic fractionation was found in terrestrial neodymium materials.

Hot Temperature↗
PubMed2005

The design of orally active iron chelators.

It is now generally accepted that it is not possible to design iron(III)-selective hexadentate chelators with high oral bioavailability. In order to achieve suitable levels of oral activity for the treatment of systemic iron overload either tridentate or bidentate molecules need to be investigated. There are a number of such molecules in clinical practice, including hydroxypyridin-4-ones, desferrithiocin analogues and bis-hydroxyphenyltriazoles. The underlying chemistry of each group is described, together with an indication of the distribution properties, redox cycling activity, and iron scavenging activity.

Administration, Oral↗
PubMed2005

[Effects of androgen on the bone].

Androgen is an anabolic steroid composed of 19 carbon atoms. As a sex hormone, it has far-ranging effects on many sites within the body, including bone metabolism. Androgen has important effects on bone development and homeostasis. It has been proved that the androgen receptor (AR) expresses in bone cells, which indicates that androgen has direct effects on bone cells. Furthermore there is convincing evidence that aromatization to estrogen is an important way of mediating the action of testosterone. Androgen not only plays an important role in gaining the peak bone mass and maintaining the bone mass, but also has a close correlation with aging-related bone loss.

Androgens↗
PubMed2005

[Extranodal Rosai-Dorfman disease].

OBJECTIVE: To investigate the diagnosis and differential diagnosis of extranodal Rosai-Dorfman disease. METHODS: Two cases of extranodal Rosai-Dorfman disease were studied using hematoxylin-eosin, and immunohistochemical staining, along with a literature review. RESULTS: The lesions of RDD were characterized by the presence of large histiocytes with emperipolesis, accompanied by infiltration of lymphocytes, plasma cells and other inflammatory cells. The large histiocytes had an abundant cytoplasm, pale to eosinophilic in appearance, positive for S-100 protein staining, with a vesicular nucleus and a small basophilic nucleolus in each cell. CONCLUSIONS: Extranodal Rosai-Dorfman disease is known as an idiopathic proliferative disease of histiocytes with a distinct morphologic feature and is very rare. Differential diagnosis from other types of fibrohistiocytic proliferation lesions is recommended.

Antigens, CD↗
PubMed2004

Characterization of Ceap-11 and Ceap-16, two novel splicing-variant-proteins, associated with centrosome, microtubule aggregation and cell proliferation.

A novel human gene, encoding two polypeptide-isoforms, has been identified from human fetal liver cDNA library. These two alternatively spliced polypeptide-variants are associated with centrosomes, and are designated Ceap-11 and Ceap-16, respectively, according to the acronym Ceap for centrosomal-associated protein and the approximate relative molecular mass. The high degree of sequence similarity between Ceap proteins of divergent species indicates that the Ceap homologous genes are significantly conserved in evolution and constitute a new gene family without any functional information until now. Human Ceap gene is mapped on 10q24.2. These two Ceap cDNA isoforms are generated by RNA alternative splicing on the 5' terminus of the Ceap gene, and are composed of four and five exons, respectively. Ceap-11 and Ceap-16 are co-immunoprecipitated and co-located with gamma-tubulin; ectopic overexpression of these two proteins in NIH3T3 cells induces microtubule aggregation and cell proliferation; the protein level of Ceap in certain tumors is significantly higher than that in corresponding normal tissues. Taken together, our data provide the first evidence for the function of Ceap-11 and Ceap-16, the two novel human proteins, namely, association with centrosome, microtubule aggregation and cell proliferation.

Alternative Splicing↗
PubMed2004

A novel eIF5A complex functions as a regulator of p53 and p53-dependent apoptosis.

Although eukaryotic translation initiation factor 5A (eIF5A) was originally designated as an "initiation factor," recent data have shown it to be also involved in apoptosis. However, the actual function of eIF5A in apoptosis is still unknown. In this study, we performed yeast two-hybrid screens to identify eIF5A-interacting proteins to help us understand the mechanisms of eIF5A. Our results demonstrated that eIF5A and syntenin could engage in a specific interaction both in vitro and in vivo and functioned collaboratively to regulate p53 activity. Our findings, for the first time, revealed a new biological activity for eIF5A as the regulator of p53. Overexpression of eIF5A or its EFP domain resulted in up-regulation of p53, and silencing eIF5A by small interfering RNA reduced the p53 protein level. Further analysis by reverse transcription PCR showed eIF5A-activated p53 transcription. The effect of eIF5A on p53 transcriptional activity was further demonstrated by the increasing expressions of p21 and Bax, well known target genes of p53. In contrast, a point mutant of eIF5A, hypusination being abolished, was revealed to be functionally defective in p53 up-regulation. Overexpression of eIF5A led to a p53-dependent apoptosis or sensitized cells to induction of apoptosis by chemotherapeutic agents. However, when eIF5A interacted with its novel partner, syntenin, the eIF5A-induced increase in p53 protein level was significantly inhibited. Therefore, eIF5A seems to be a previously unrecognized regulator of p53 that may define a new pathway for p53-dependent apoptosis, and syntenin might regulate p53 by balancing the regulation of eIF5A signaling to p53 for apoptosis.

Animals↗
PubMed2004

[Analysis of bacterial culture and C. pneumoniae DNA detection of chronic pharyngitis].

OBJECTIVE: To research the pathogenic microorganism characters of chronic pharyngitis. METHOD: Samples taken from pharyngeal swab from patient with chronic pharyngitis were routinely cultured; mp-DNA were detected by polymerase chain reaction (PCR). RESULT: Of all the cases, 5 patients were DNA(+), among which 3 patients got obvious effect after 2 weeks treatment. The bacterial abnormally was present in 15 patients (31.5%), among which 6 patients got obvious effect and 2 patients got no effect after 2 weeks treatment. CONCLUSION: The pathogenic abnormally may be present in some patients with chronic pharyngitis, most of which appeared to be an internal disorder of the proper microflores. C. pneumoniae may be an aetiological agent for chronic pharyngitis. An appropriate antimicrobial treatment should be considered in some cases.

Adolescent↗
PubMed2004

Schwann cell apoptosis in Wallerian-degenerated sciatic nerve of the rat.

OBJECTIVE: To investigate systematically Schwann cell apoptosis in Wallerian-degenerated sciatic nerve of the rat, and evaluate its time-related feature. METHODS: Ninety-five SD rats were divided randomly into one normal group (8 rats) and 11 experimental groups (66 rats, 6 in each). Both hind legs of each rat in experimental groups were randomly divided into test leg (sciatic nerve transected) and control one (nerve uninjured). All test legs constituted a test group and all control legs constituted a control one. After operation, all rats were respectively sacrificed at 1 h, 6 h, 12 h, 24 h, 2 d, 3 d, 4 d, 8 d, 14 d, 21 d, and 30 d. We analyzed the specimens of mid-distal sciatic nerve, especially the morphological changes of the nerve, the different expression levels of S-100 protein and apoptosis-related proteins such as Bcl-2, Bax, and Fas in Schwann cells. The TUNEL method was used to detect the apoptotic rate of Schwann cells. RESULTS: (1) The test group showed Wallerian degeneration. The number of Schwann cells began to decrease at 24 h, obviously decreased on day 3 and 4, then began to increase from day 8 and formed Bungner belt after 14 days. (2) Schwann cells generally expressed S-100 at a low level in all groups. The control group was not significantly different from the normal group. The test group had statistical significance at 1 h and day 21. (3) As an inhibitory gene protein of Schwann cell apoptosis, Bcl-2 positive rates in the control and test groups apparently elevated and were statistically different from the normal group. (4) As a promotive gene protein of Schwann cell apoptosis, the control and test groups expressed Bax at a high level and were statistically different from the normal group. (5) As a promotive gene protein of Schwann cell apoptosis, Fas positive rate in control group was slightly elevated, but had no statistical significance compared with the normal group. Fas positive rate in test group continuously elevated in a fluctuant way, with highly statistical significance compared with the normal group. (6) TUNEL detection further proved that Schwann cell apoptosis rarely existed in the normal group, and the left sciatic nerve had no statistical significance compared with the right sciatic nerve. While the test group showed lots of apoptotic nuclei at 6 h, 2 d, 4 d, and 21 d. It had highly statistical significance compared with the normal group. CONCLUSIONS: Schwann cell apoptosis does exist in Wallerian-degenerated sciatic nerve of the rat after transection. Schwann cell apoptosis and its apoptotic genes expression have a time-related feature.

Analysis of Variance↗
PubMed2004

[Effects of different doses of hydrocortisone on acute lung injury in rats with early septic shock induced by Escherichia coli].

OBJECTIVE: To observe the effects of different doses of hydrocortisone (HC) on acute lung injury (ALI) and inflammatory response in rats at early stage of septic shock induced by Escherichia coli and to investigate the possible mechanisms for such differences. METHODS: ALI model of early septic shock was induced in rats by two injections of Escherichia coli at 5 hours interval, with the first intraperitoneal injection of 6.50 x 10(10) cfu/kg and followed by an external jugular vein injection of 2.00 x 10(11) cfu/kg. Forty Wistar rats were randomly divided into the following five groups: normal control, ALI without HC treatment, high-dose HC (150 mg/kg), medium-dose HC (20 mg/kg) and low-dose HC (6 mg/kg). Two hours after the treatment, the specimens were collected for histopathological examination and the biological indexes of lung injury were measured. The expressions of intercellular adhesion molecule-1 (ICAM-1) and glucocorticoid receptor (GR) in lung tissues were also investigated by immunohistochemical assays. RESULTS: The biological indexes of lung injury [wet/dry weight ratio (g/g), total protein concentration in bronchoalveolar lavage fluid (mg/L) and lung permeability index (10(-3))] in ALI group (4.76 +/- 0.10, 278.96 +/- 60.45, 4.73 +/- 0.60) were significantly increased as compared to those in normal control group (4.10 +/- 0.07, 67.46 +/- 13.27, 1.12 +/- 0.15) (P < 0.05). The grades of ALI pathologic changes in ALI group (11.13 +/- 1.13) was significantly higher than that in the normal control group (0.50 +/- 0.53, P < 0.05). The ratio of expression area of ICAM-1 in ALI group (0.149 +/- 0.037) was significantly increased as compared to that in the normal control group (0.051 +/- 0.018) (P < 0.05). The ratio of expression area of GR all group (0.043 +/- 0.037) was significantly decreased as compared to that in the normal Control group (0.124 +/- 9.040) (P < 0.05) After administration of HC, all the lung injury indexes, pathological grades and the ratios of expression area of ICAM-1 and GR were significantly improved, with the most remarkable effects observed in the low-dose HC group. The expressions of ICAM-1 and GR showed a significantly negative linear correlation (r = 0.55, P < 0.0001). CONCLUSION: These results indicated that the low-dose HC treatment had the most remarkable effects of improving the biological indexes of lung injury, inflammatory mediators and pathological changes. These HC dose dependent therapeutic effects might be associated with the level of GR expression.

Acute Lung Injury↗
PubMed2004

[Effects of hydrocortisone on oxygen free radicals released by polymorphonuclear neutrophils in lipopolysaccharide-induced acute lung injury in mice].

BACKGROUND: Corticosteroid treatment of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) has been one of the most controversial clinical issues in critical care. Although the administration of high-dose corticosteroids does not benefit patients with early septic shock and ARDS, recent clinical trials have indicated that treatment with relatively low-dose corticosteroids (2 to 3 mg/kg/day of methylprednisolone or equivalent) may improve outcome when used for late ARDS or persistent septic shock. The underlying mechanism was not fully clarified. Whether the administration of corticosteroids can arrest neutrophil-driven organ injury once started remains to be elucidated. OBJECTIVE: To observe the effects of hydrocortisone (HC, 6 mg/kg) on oxygen free radicals (OFR) released by PMN and pulmonary pathological changes in rat ALI model induced by lipopolysaccharide (LPS), to investigate the possible mechanism through which corticosteroids exert protective effect on ALI. METHODS: A rat model of ALI was induced by peritoneal injection of 2 x 10(12) Escherichia coli/kg. Fifty-six rats were randomly divided into three groups: normal control group, LPS group and HC group (6 mg/kg). Samples were collected 2 h, 4 h and 6 h after giving LPS to LPS and HC group (6 h after giving normal saline in normal control group) to measure the level of OFR released by PMN using chemiluminescence method based on lumino, and to compae of pulmonary pathological changes among the three groups. RESULTS: Pathological examination with light microscope in LPS group showed thickened pulmonary interstitia, inflammatory cell infiltration, edema and hemorrhage, which were in accordance with the features of ALI. There were significant differences in the release of OFR by PMN among the three groups (P < 0.01). The level of OFR released by PMN in LPS group was significantly higher than that of the control group, and continued to increase during the observation period (2 - 6 h after LPS). The release of OFR by PMN in HC group was significantly suppressed as compared with LPS group, which was peaked at 4 h after LPS injection (to 98.2%); there were also significant differences in the grades of ALI pathologic changes among the three groups (P < 0.01). The grades of ALI pathologic changes in LPS group were significantly increased when compared with the normal control group (P < 0.05) while significantly decreased in HC group as compared with LPS group (P < 0.05). CONCLUSION: It was demonstrated in the LPS induced ALI model that OFR might play an important role in onset of ALI. Intervening with HC (6 mg/kg) treatment could ameliorate the lung injury and exert significant and sustained suppression on the release of OFR by PMN, showing that HC has a protective effect on LPS induced ALI and its theraputic effect occurs possibly through suppression on the release of OFR by PMN.

Acute Lung Injury↗
PubMed2004

[Microwave assisted UV electrodeless discharge lamp photochemical degradation of 4-chlorophenol in aquatic solutions].

A microwave assisted UV electrodeless discharge lamp system (MW/UV) was used for photo-degradation of 4CP simulated wastewater. In order to evaluate the degradation efficiency of 4CP, UV spectrophotometry and ion chromatography were used for determination of 4CP and Cl- respectively. The degradation rate in MW/UV system was higher than that in the UV system within 120min, which were 52.40% and 21.56% respectively. The degradation efficiency was improved by increasing pH value of the solution, aerating O2 gas, enhancing light intensity, or adding H2O2 oxidant. The degradation of 4CP under MW/UV accords with the first order kinetics equation.

Chlorophenols↗
PubMed2003

[Myocardial protective effect of L-carnitine in cardioplegia solution on patients undergoing heart valve replacement operation].

OBJECTIVE: To investigate the myocardial protective effect of L-carnitine as an ingredient of cardiac arresting solution in the process of heart valve replacement operation. METHODS: 69 cases undergoing heart valve replacement with cardiopulmonary bypass (CPB), 47 males and 22 females, aged 48.17 +/- 14.22 (16 approximately 74 years), were divided into 3 groups: test group I (n = 22, 12 g/L L-carnitine was put in the St. Thomas II cold crystal cardiac arresting liquid), test group II (n = 24, 6 g/L L-carnitine was put in the St. Thomas II cold crystal cardiac arresting liquid), and control group (n = 23, no L-carnitine was put in the St. Thomas II cold crystal cardiac arresting liquid). Before operation, 20 minutes after the beginning of shunt, after the finish of shunt, and 8 hours, one day, 3 days, and 7 days after operation venous blood was drawn to test the serum cardial tropnin I (cTnI), aspartate transaminase, lactate dehydrogenase, creatine kinase (CK) and CK-MB isozyme. Heart color ultrasonography was conducted to test the cardiac index (CI) and left heart ejecting fraction (EF) one day before operation and 7 days after operation. Before shunt and by the end of intracardiac procedure a bit of myocardial tissue was taken to undergo electron microscopy. The amounts of vaso-active drugs, such as dopamine and dobutamine, used postoperatively, and the postoperative cardiac auto-rebeating rate were recorded. RESULTS: The Amounts of vaso-active drugs used after operation was 329 +/- 54 mg in the test group I and 339 +/- 47 mg in the test group II, both significantly less than in the control group (669 +/- 56 mg, both P < 0.01) without a significant difference between the 2 test groups. Since the end of CPB to 3 days after operation, the serum levels of cTnI, aspartate transaminase, lactate dehydrogenase, CK and CK-MB isozyme were significantly lower in the 2 test groups than in the control group (P < 0.05 or P < 0.01). The serum level of cTnI in test group I was significantly lower than in the test group II (5.71 +/- 1.14 ng/ml vs 7.87 +/- 1.89 ng/ml 1 day postoperatively (P < 0.05), and 5.01 +/- 0.89 ng/ml vs 7.53 +/- 1.43 ng/ml 3 days postoperatively (P < 0.05). The postoperative cardiac auto-rebeating rate was 87.9% in the test group I and 74.3% in the test group II, both significantly higher than that in the control group (45.7%, P < 0.05 and P < 0.01). Heart color ultrasonogram showed that 7 days postoperatively the CI index was 2.86 +/- 0.55 and 2.74 +/- 0.56 in the 2 test groups, significantly higher than that in the control group (2.11 +/- 0.35, both P < 0.05), and the left heart EF were 64.3 +/- 8.6 and 59.1 +/- 6.7 in the 2 test groups, both significantly higher than that in the control group (51.7 +/- 4.9, both P < 0.05). Electron microscopy showed only slight swelling of mitochondria in the cardial cell and the myocardial fiber was intact by the end of operation in the 2 test groups without significant difference between these 2 groups, however, in the control group swelling of mitochondria with vesicle formation, fissure of part of mitochondrial ridges, and disappearance of glycogen particles were found. CONCLUSION: Antegrade coronary perfusion of L-carnitine has a good protective effect on myocardium and is worth spreading for heart valve replacement patients with cardiopulmonary bypass.

Adolescent↗
PubMed2003

Proteomic analysis of ubiquitin-proteasome effects: insight into the function of eukaryotic initiation factor 5A.

The global effect of ubiquitin-proteasome (UP) inhibitors on leukemic cell proteome was analysed. A total of 39 protein spots, affected by UP inhibitors, were identified, including 11 new apoptosis-associated proteins. They are involved in different cellular functions and four were associated with caspase-3 activation. Eukaryotic initiation factor 5A (eIF-5A) was identified in two spots; however, the peptide mass-fingerprinting for the accumulated one included a peptide with lysine50, indicating that hypusine formation was suppressed during UP inhibitor-induced apoptosis. Hypusine modification ensues immediately following translation of eIF-5A precursor, unless cells are treated with the modification inhibitors diaminoheptane. However, UP inhibitors induced a much stronger accumulation of unmodified eIF-5A compared to the effect of diaminoheptane. We further showed the unmodified eIF-5A was regulated in a proteasome-dependent manner. Inhibition of hypusine formation by diaminoheptane triggered apoptosis, but of particular interest is the finding that eIF-5A expression inhibition by antisense oligodeoxynucleotides significantly enhanced the stimulating effect of GM-CSF on cell growth. Therefore, the eIF-5A accumulation played important roles in the apoptosis induced by UP inhibitors. Moreover, hypusine inhibition in apoptosis was further revealed to be associated with the subcellular localization of eIF-5A. Our data pave the way to a better understanding of the mechanisms by which UP system has been linked to apoptosis.

Acetylcysteine↗