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Biomedical subjects

Tao Zhu

Publications and source records attributed to Tao Zhu.

At least 37 records · Page 2Linked to original sources
PubMed2006

Pin1 contributes to cervical tumorigenesis by regulating cyclin D1 expression.

The prolyl isomerase Pin1, which specifically catalyzes conformational changes in certain proline-directed phosphorylation sites, is thought to be a critical catalyst for multiple oncogenic pathways. However, little is known about the role of Pin1 in human cervical cancer. Our previous study showed that Pin1 was overexpressed in cervical cancer tissues as well as cell lines. In this study, whether Pin1 is involved in cervical oncogenesis by regulating cyclin D1 was explored and the potential of Pin1-targeted gene silencing in inhibiting cellular growth and tumorigenicity in cervical cancer was investigated. A Pin1-directed shRNA and a sense Pin1 plasmid were constructed, and then the effects of the shRNA and the sense plasmid on HeLa cells were evaluated. The results showed that Pin1 directly regulated cyclin D1 levels. In addition, silencing Pin1 with RNAi significantly reduced cancer cell proliferation, colony formation, and strongly enhanced the apoptosis of HeLa cells. It is suggested that Pin1 may contribute to cervical tumorigenesis by regulating cyclin D1 expression and Pin1 may serve as a promising molecular target for diagnostics and therapeutics in cervical cancer.

Apoptosis↗
PubMed2005

Simple, one-step synthesis of gold nanowires in aqueous solution.

A simple procedure to synthesize gold nanowires based on the reduction of hydrogen tetrachloroaurate by 2-mercaptosuccinic acid in aqueous solution is presented. This procedure requires no additional capping or reduction agent and produces wires with an apparent curly morphology several micrometers in length with diameters as thin as 15 nm. Some of the wires produced end in a ribbonlike structure, finally terminated by a flat triangular prism. Investigations by scanning electron microscopy, transmission electron microscopy (bright and dark field), scanning transmission electron microscopy, and atomic force microscopy as well as conductivity measurements indicate fully connected, polycrystalline gold objects.

Journal Article↗
PubMed2005

Role of hTERT in apoptosis of cervical cancer induced by histone deacetylase inhibitor.

Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase holoenzyme as well as the rate-limiting component of the telomerase enzyme complex. However, the role of the hTERT in apoptosis induced by histone deacetylase inhibitor has only been marginally addressed. For the first time, our study demonstrated that trichostatin A (TSA) briefly activated the proliferation of cervical cancer cell lines, HeLa and SiHa, within 12 h, but then inhibited cell growth after that time point. In response to TSA, hTERT expression, telomerase activity, and telomere length also underwent similar changes during the same time frame. Furthermore, the data in our study showed that cells transfected with dominant negative hTERT were more likely to undergo apoptosis induced by TSA than cells transfected with wild-type hTERT. The cyclin/cdk inhibitor p21waf1 was down-regulated by hTERT without changing the expression of p53. Results from this study suggest that the hTERT might be a primary target of TSA and the anti-apoptosis effect of hTERT might be carried out through a p21waf1-dependent and p53-independent pathway.

Apoptosis↗
PubMed2005

[Clinical effects of combination chemotherapy with irinotecan hydrochloride and cisplatin on cervical cancer: study of 46 patients].

OBJECTIVE: To evaluate the efficacy and toxicity of the combination chemotherapy of irinotecan hydrochloride plus cisplatin on cervical cancer. METHODS: Forty-six patients with cervical cancer, 43 with squamous cell carcinoma, 2 adenocarcinoma, and 1 small cell carcinoma, 41 being treated initially and 5 being recurrent cases of which 2 had undergone radiotherapy plus chemotherapy, 2 radical hysterectomy plus pelvic radiotherapy after operation, and 1 radical hysterectomy plus chemotherapy, aged 38 (22-61), were treated with irinotecan hydrochloride, 60 mg/m(2) in 250 ml normal saline administered on days 1, 8, and 15 by intravenous infusion over 60 min, plus cisplatin, 60 mg/m(2) in 500 ml 5% glucose given on day 1. This regimen was repeated every 28 days. Effectiveness evaluation was conducted after 1-2 courses for the initially treated patients and after 2-6 courses for the recurrent patients. RESULTS: Totally 79 courses of treatment were given to the 41 patients. After 1-2 courses 4 (9.8%) of the 41 stage Ib2-IIIb initially treated patients achieved complete remission, 30 (73.2%) achieved partial remission, and 7 (17.1%) remained at stationary phase with a overall effective rate of 82.9%. Of the 29 IIb and IIIb stage advanced patients who failed to receive operation originally 20 patients (69%) succeeded to be treated by radical hysterectomy after 1 to 2 courses when the tumorless space between the uterine and the pelvic wall > or = 3 cm with an operatibility rate of 69%. Of the 5 recurrent patients 1 case achieved complete remission, 2 partial remission, and 2 remained stable; none progression of disease was observed after 4-6 courses. The main toxic response and side effect included myelosuppression and diarrhea. CONCLUSION: Effective neoadjuvant chemotherapy on cervical cancer, combination therapy of irinotecan hydrochloride and cisplatin win opportunity for treatment and improves their life quality with tolerable side effects.

Adenocarcinoma↗
PubMed2005

Formation mechanism of nonspherical gold nanoparticles during seeding growth: roles of anion adsorption and reduction rate.

A small section of nonspherical particles can be observed in the further growth of spherical gold colloids exposed to a mixture of NH2OH and HAuCl4. The concentration ratio of [NH2OH]:[HAuCl4] is critical for the formation of nonspherical particles as higher ratios produce lower yields and smaller of such particles. These concentrations also affect the reaction kinetics; the reaction rate increases with [NH2OH], while independent of [HAuCl4], which we believe is due to the specific adsorption of AuCl4- onto gold surface. These nonspherical particles come from the preferential growth of {111} facets as indicated by their TEM images and electron diffraction patterns. We propose this preferential growth is ascribed to the preferential adsorption of AuCl4- on {111} facets, and some competition which determines the yield of nonspherical particles exists between the AuCl4- adsorption and the AuCl4- reduction, faster reduction counteracting the effect of this preferential adsorption and thus suppressing nonspherical particle. This result probably provides some guidance to develop a shape-controlled synthesis of gold particles without any additives.

Journal Article↗
PubMed2005

p44/42 MAP kinase-dependent regulation of catalase by autocrine human growth hormone protects human mammary carcinoma cells from oxidative stress-induced apoptosis.

Previous microarray expression analyses have indicated autocrine human growth hormone (hGH) regulation of genes involved in the oxidative stress response. Expression analysis of antioxidant enzymes revealed that autocrine hGH increased both the mRNA and protein levels of catalase, superoxide dismutase 1 (SOD1), glutathione peroxidase and glutamylcysteine synthetase but not that of SOD2. As a consequence, autocrine hGH increased the antioxidant capacity of mammary carcinoma cells and protected against oxidative stress-induced apoptosis. Catalase activity was increased by autocrine production of hGH in mammary carcinoma cells and a catalase inhibitor abrogated protection from oxidative stress afforded by autocrine hGH. Autocrine hGH transcriptionally regulated catalase gene expression in a p44/42 MAP kinase-dependent manner and inhibition of MEK concordantly abrogated the protective effect of autocrine hGH against oxidative stress-induced apoptosis. Given that increased cellular oxidative stress is a key effector mechanism of specific chemotherapeutic agents, we propose that antagonism of autocrine hGH will improve the efficacy of chemotherapeutic regimes utilized for human mammary carcinoma.

Apoptosis↗
PubMed2005

Reproducible patterning of single au nanoparticles on silicon substrates by scanning probe oxidation and self-assembly.

This paper describes a rational approach for reproducibly patterning single Au nanoparticles, 15-20-nm diameter, on silicon wafer substrates. The approach uses scanning probe oxidation (SPO) to pattern silicon oxide nanodomain arrays on silicon substrates modified with octadecyltrimethoxysilane (OTS). It was usually found using aminopropyltrimethoxysilane (APS) that Au nanoparticles only assembled at the domain boundaries probably because of asymmetrically distributed hydroxyl groups. To generate uniformly distributed hydroxyl groups on oxide domains, we employed a two-step treatment to etch and oxidize the substrate. With this treatment, oxide domains consistently attached Au nanoparticles to maximum capacity. Single Au nanoparticles were readily patterned by fabricating oxide nanodomains with a diameter below 30 nm. We also investigated the deposition of APS on OTS monolayers, which resulted in the assembly of Au nanoparticles outside of the oxide domains, and proposed two alternative methods to inhibit it.

Journal Article↗
PubMed2005

Oncogenic transformation of human mammary epithelial cells by autocrine human growth hormone.

The human growth hormone (hGH) gene is expressed in the normal human mammary epithelial cell and its expression increases concomitant with the acquisition of proliferative lesions. Herein we demonstrate that autocrine production of hGH in human mammary carcinoma cells dramatically enhances anchorage-independent growth in a Janus kinase 2-dependent manner. Forced expression of the hGH gene in immortalized human mammary epithelial cells increased proliferation, decreased apoptosis, altered the cellular morphology and resulted in oncogenic transformation. Autocrine hGH was therefore sufficient to support anchorage-independent growth of immortalized human mammary epithelial cells and tumor formation in vivo. Moreover, autocrine hGH disrupted normal mammary acinar architecture with luminal filling and deregulated proliferation in three-dimensional epithelial cell culture. Autocrine hGH utilized homeobox A1 to govern the transcriptional program required for autocrine hGH-stimulated oncogenic transformation of human mammary epithelial cells, including transcriptional up-regulation of c-Myc, cyclin D1, and Bcl-2. Forced expression of a single orthotopically expressed wild-type gene is therefore sufficient for oncogenic transformation of the immortalized human mammary epithelial cell.

Breast↗
PubMed2005

Surface-enhanced Raman scattering of p-aminothiophenol on a Au(core)/Cu(shell) nanoparticle assembly.

Surface-enhanced Raman scattering (SERS) of p-aminothiophenol (PATP) molecules adsorbed onto assemblies of Au(core)/Cu(shell) nanoparticles is reported. We compare it with the SERS spectrum of PATP adsorbed onto gold nanoparticles: both the absolute and relative scattered intensities of various bands in the two spectra are very different. The difference in relative intensity can be ascribed to chemical effects; the chemical enhancement ratio of the two substrates is approximately 3-5. A theoretical analysis based on a charge-transfer model is carried out, which yields a consistent result and shows that the difference in chemical enhancement is mainly due to the state densities and Fermi levels of the substrates. The difference in absolute intensity originates from electromagnetic (EM) enhancement. EM enhancement of Au(core)/Cu(shell) nanoparticles is unlike that of single-component gold or copper SERS-active substrates. The core/shell particle size for optimal enhancement is about 20 nm in the case of a 632.8 nm incident laser (the size ratio of the core and shell layers is about 0.6).

Journal Article↗
PubMed2005

[Expression of human telomerase reverse transcriptase in cervix cancer and its significance].

OBJECTIVE: To investigate the expression of human telomerase reverse transcriptase (hTERT) mRNA and protein in cervix cancer, cervical intraepithelial neoplasia (CIN) and normal cervix. METHODS: Expression of hTERT mRNA and the other two subunits of telomerase, human telomerase RNA component (hTR), human telomerase-associated protein (hTP1) was determined by RT-PCR in 3 cervix cancer cell lines, 2 diploid cell lines, 38 cases of cervix cancer, 16 cases of CIN and 20 cases of normal cervix. Telomerase activity was also examined by telomeric repeat amplification protocol enzyme-linked immunosorbent assay (TRAP-ELISA). Expression of hTERT protein was detected in all the cell lines and 101 cases of paraffinized cervix tissue sections. RESULTS: hTERT mRNA expression was detected in all of the three cervix cancer cell lines, 81.6% of cervix cancer, 37.5% of CIN, 5.0% of normal cervix, while in neither of the two diploid cell lines. The other two subunits of telomerase were prevalently expressed in all of the cell lines and most cervix tissues. There was a strong correlation between hTERT mRNA expression and telomerase activity. Immunostaining also revealed that hTERT protein was expressed in all three cervix cancer cell lines, 65.5% of cervix cancer, 28.0% of CIN and 4.8% of normal cervix. CONCLUSION: Up-regulation of hTERT may play an important role in the development of CIN and cervix cancer, hTERT could be used as an early diagnostic biomarker for cervix cancer.

Carrier Proteins↗
PubMed2005

[Automated anesthesia record system].

Based on Client/Server architecture, a software of automated anesthesia record system running under Windows operation system and networks has been developed and programmed with Microsoft Visual C++ 6.0, Visual Basic 6.0 and SQL Server. The system can deal with patient's information throughout the anesthesia. It can collect and integrate the data from several kinds of medical equipment such as monitor, infusion pump and anesthesia machine automatically and real-time. After that, the system presents the anesthesia sheets automatically. The record system makes the anesthesia record more accurate and integral and can raise the anesthesiologist's working efficiency.

Anesthesia↗
PubMed2004

BOD: a customizable bioinformatics on demand system accommodating multiple steps and parallel tasks.

The integration of bioinformatics resources worldwide is one of the major concerns of the biological community. We herein established the BOD (Bioinformatics on demand) system to use Grid computing technology to set up a virtual workbench via a web-based platform, to assist researchers performing customized comprehensive bioinformatics work. Users will be able to submit entire search queries and computation requests, e.g. from DNA assembly to gene prediction and finally protein folding, from their own office using the BOD end-user web interface. The BOD web portal parses the user's job requests into steps, each of which may contain multiple tasks in parallel. The BOD task scheduler takes an entire task, or splits it into multiple subtasks, and dispatches the task or subtasks proportionally to computation node(s) associated with the BOD portal server. A node may further split and distribute an assigned task to its sub-nodes using a similar strategy. In the end, the BOD portal server receives and collates all results and returns them to the user. BOD uses a pipeline model to describe the user's submitted data and stores the job requests/status/results in a relational database. In addition, an XML criterion is established to capture task computation program details.

Computational Biology↗
PubMed2004

Surfactant-directed polypyrrole/CNT nanocables: synthesis, characterization, and enhanced electrical properties.

We describe here a new approach to the synthesis of size-controllable polypyrrole/carbon nanotube (CNT) nanocables by in situ chemical oxidative polymerization directed by the cationic surfactant cetyltrimethylammonium bromide (CTAB) or the nonionic surfactant polyethylene glycol mono-p-nonylphenyl ether (Opi-10). When carbon nanotubes are dispersed in a solution containing a certain concentration of CTAB or Opi-10, the surfactant molecules are adsorbed and arranged regularly on the CNT surfaces. On addition of pyrrole, some of the monomer is adsorbed at the surface of CNTs and/or wedged between the arranged CTAB or Opi-10 molecules. When ammonium persulfate (APS) is added, pyrrole is polymerized in situ at the surfaces of the CNTs (core layer) and ultimately forms the outer shell of the nanocables. Such polypyrrole/CNT nanocables show enhanced electrical properties; a negative temperature coefficient of resistance at 77-300 K and a negative magnetoresistance at 10-200 K were observed.

Journal Article↗
PubMed2004

Changes of interleukin-1 beta, tumor necrosis factor alpha and interleukin-6 in brain and plasma after brain injury in rats.

OBJECTIVE: To study the changes of interleukin-1 beta (IL-1beta), tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) levels in brain and plasma after brain injury and to assess the relationship between the cytokine levels and injury severity in rats. METHODS: A total of 51 male Wistar rats, weighing 280-340 g, were anesthetized with chloral hydrate (400 mg/kg body weight) through intraperitoneal injection and fixed on a stereotaxic instrument. Severe brain injury was created in 16 rats (severe injury group) and moderate brain injury in 18 rats (moderate injury group) by a fluid percussion model, and cytokine levels of IL-1beta, TNFalpha and IL-6 were measured with biological assay. And sham operation was made on the other 17 rats (control group). RESULTS: In the control group, the levels of IL-1beta, TNFalpha and IL-6 were hardly detected in the cortex of the rats, but in the ipsilateral cortex of the rats in both injury groups, they increased obviously at 8 hours after injury. The increasing degree of these cytokines had no significant difference between the two injury groups. The levels of IL-6 in the plasma of all the rats increased slightly, whereas the levels of IL-1beta and TNFalpha were undetectable. CONCLUSIONS: The increase of IL-1beta, TNFalpha and IL-6 levels is closely related to brain injury. The increased cytokine levels in the central nervous system are not parallel to those in the peripheral blood. It suggests that inflammatory cytokines play important roles in the secondary neural damage after brain injury.

Animals↗