Biomedical subjects

Yang Yang

Publications and source records attributed to Yang Yang.

At least 127 records · Page 7Linked to original sources

PubMed2005

Oridonin, a diterpenoid purified from Rabdosia rubescens, inhibits the proliferation of cells from lymphoid malignancies in association with blockade of the NF-kappa B signal pathways.

This study found that oridonin, a natural diterpenoid purified from Rabdosia rubescens, inhibited growth of multiple myeloma (MM; U266, RPMI8226), acute lymphoblastic T-cell leukemia (Jurkat), and adult T-cell leukemia (MT-1) cells with an effective dose that inhibited 50% of target cells (ED50) ranging from 0.75 to 2.7 microg/mL. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining showed that oridonin caused apoptosis of MT-1 cells in a time-dependent manner. We explored effects of oridonin on antiapoptotic Bcl-2 family members and found that it down-regulated levels of Mcl-1 and BCL-x(L), but not Bcl-2 protein, in both MT-1 and RPMI8226 cells. Further studies found that oridonin inhibited nuclear factor-kappa B (NF-kappa B) DNA-binding activity in these cells as measured by luciferase reporter gene, ELISA-based, and electrophoretic mobility shift assays. Oridonin also blocked tumor necrosis factor-alpha- and lipopolysaccharide-stimulated NF-kappa B activity in Jurkat cells as well as RAW264.7 murine macrophages. Of note, oridonin decreased survival of freshly isolated adult T-cell leukemia (three samples), acute lymphoblastic leukemia (one sample), chronic lymphocytic leukemia (one sample), non-Hodgkin's lymphoma (three samples), and MM (four samples) cells from patients in association with inhibition of NF-kappa B DNA-binding activity. On the other hand, oridonin did not affect survival of normal lymphoid cells from healthy volunteers. Taken together, oridonin might be useful as adjunctive therapy for individuals with lymphoid malignancies, including the lethal disease adult T-cell leukemia.

Adult↗

PubMed2005

Functional disability, disability transitions, and depressive symptoms in late life.

OBJECTIVE: This article addresses how stable functional disability statuses and disability transitions are related to change in depressive symptoms in the elderly. METHOD: The authors estimate longitudinal residual change models using two waves of data, 1986 and 1992, from the National Institute of Aging Established Populations for Epidemiologic Studies of the Elderly, Duke University. RESULTS: Both stable disability statuses and transitions in disability statuses are significantly related to change in depressive symptoms (Center for Epidemiologic Studies depression scale [CES D]). Stable disability statuses in strength and mobility, instrumental activities of daily living (IADL) items and activities of daily living (ADL) items have increasing effects on increment in CES-D scores by the follow-up. The onset of disability has stronger effects on change in CES-D scores than recovery. These effects also differ by types of transitions in disability statuses. DISCUSSION: The authors discuss alternative interpretations of the findings and methodological concerns and also suggest avenues for future research.

Activities of Daily Living↗

PubMed2005

Inhibition of AF116909 gene expression enhances the differentiation of neural stem cells.

OBJECTIVES: Neural stem cells (NSCs) are self-renewed, pluripotent cells that can differentiate into neurons, astrocytes and oligodendrocytes. Such multipotency that allows production of specific types of nerve cells for basic research and therapeutic purposes depends on how these cells are directed in their differentiation. Here, we investigate the function of the AF116909 gene in the differentiation of NSC. METHODS: NSC culture was isolated from the striatum corpora of embryonic brain tissues in a 14-day pregnant rat. A constructed RNAi (RNA-mediated interference) vector was transfected to knock down the expression of this gene. Afterwards, RT-PCT was applied to examine the presence of endogenous AF116909 mRNA and the effect of RNA interference. RESULTS: After the knockdown of this gene, we detected that the differentiation rate of cells was enhanced to 80% on the 11th day in comparison with 12% in the control cells transfected with the expression vector alone. DISCUSSION: These findings suggest that AF116909 functions in inhibiting the differentiation of NSCs, and AF116909 gene-targeting by RNAi provides a useful method to study the differentiation mechanisms of NSCs.

Animals↗

PubMed2005

Millisecond-accurate synchronization of visual stimulus displays for cognitive research.

A widely adopted approach in cognitive psychology research is to analyze changes in the response time to a stimulus onset in order to infer information about the cognitive functioning of a subject being tested. But current techniques have inherent variations in the timing between stimulus activation and stimulus display of up to tens of milliseconds, thereby introducing significant errors when response time or the latency of neural responses is measured. This article presents a novel yet easy-to-implement solution for improving resolution in the synchronizing of stimulus activation and stimulus display. Unlike traditional methods in which the stimulus onset is set as the time at which the routine for displaying the stimulus is called, this approach uses DirectX to monitor the scan line of CRTs and sets the stimulus onset to the time at which the scan line arrives at the position where the stimulus is to be drawn. This approach removes the uncertainty involved in having a time delay between the activation of the display routine and the actual time at which the display occurs, improving the accuracy of response time and latency period measurements to within 200 microsec. With a specially developed driver, this solution can generate a trigger signal synchronized precisely with the stimulus onset in all popular Windows systems (including Windows 2000/XP).

Cognition↗

PubMed2005

Methylation of the MLH1 gene in hematological malignancies.

Hypermethylation of the MLH1 gene has been described in many kinds of human cancers with microsatellite instability (MSI). However, it is not clear whether the same mechanism occurs in hematological malignancies. Genomic DNA was extracted from 31 patients with adult T-cell leukemia/lymphoma (ATL), 9 patients with acute lymphoblastic leukemia (ALL) who had MSI, and 12 leukemia and lymphoma cell lines with MSI. Aberrant methylation of the MLH1 gene was found in 2/31 (6%) ATL patients, and in 1/12 (8%) cell lines with MSI. MLH1 promoter was not methylated in either of the twelve peripheral blood samples from normal individuals or ALL samples. The MLH1 gene was expressed in the normal peripheral blood samples, but not in the MLH1-methylated cell line KCL22. Demethylation with 5-Azacytidine treatment restored MLH1 expression in the KCL22 cell line. Methylation of the MSH2 gene was not found in any of the samples. Our data show that hypermethylation of the MLH1 gene is occasionally involved in the pathogenesis of hematological malignancies, but is not always associated with MSI.

Adaptor Proteins, Signal Transducing↗

PubMed2005

[Damage effect of hepatocytic growth-promoting substance from neonatal calf on DNA of HL-60 cells].

The present study was aimed to investigate the damage effect of hepatocyte growrh promoting substance (HGS) on the HL-60 cell DNA in vitro and to explore the possible mechanism underlying the effect. Experiment was divided into 3 groups: one was control group, in which 0.9% NaCl solution was added, and other two were experimental group 1 and group 2, where 22.5 microg/ml and 40 microg/ml HGS were added, respectively. HL-60 cell growths were compared between groups with and without HGS. Single cell gel electrophoresis (SCGE) was used to detect DNA damage of HL-60 cell. DNA electrophoresis was used to detect the apoptosis of HL-60 cells caused by HGS. The results showed that the inhibitory effects of HGS on growth of HL-60 cells were observed in group with 22.5 microg/ml and group with 40 microg/ml after culture for 2 days, the DNA ladder and the apoptosis of HL-60 cells occurred in these 2 groups on day 2 after addition of HGS, the counts of HL-60 cells with comet tail in these experimental groups were found to be more increased in comparison with control group. In conclusion, the HGS can inhibit the growth of HL-60 cell and the apoptosis of HL-60 cells should be induced through pathway of DNA damage caused by HGS.

Animals↗

PubMed2005

[Short-term curative effect of amifostine combined with rhEPO on aged patients wilh myelodysplastic syndrome].

The aim of this study was to investigate the curative effect of amifostine (AMF) combined with recombinant human erythropoietin (rhEPO) on the aged patients with myelodysplastic syndrome. Two aged MDS patients (one aged 91; another 86) were treated with amifostine and rhEPO over a period of 4 weeks. The results showed that a short-term curative effect was observed and transfusion interval was prolonged in both patients after 4 week treatment with 5 x 0.4 g AMF plus 3 x 6,000 U rhEPO per week. The reticulocyte count in MDS-RA patient returned to normal at first week of treatment and still remained in normal level for 4 weeks; leukocyte, hemoglobin and platelet values in peripheral blood of MDS-RCMD patient obviousby increased, the abnormally increased reticulocyte value displayed a decrease trend after amifostine plus rh-EPO treatment. In conclusion, amifostine plus rhEPO may have a good therapeutic effect for aged MDS patients, and its clinical long-term curative effect still needs further evaluation.

Aged↗

PubMed2005

[Relationship between the amount of nitric oxide and apoptosis of germ cells in the semen of infertile men].

AIM: To explore the relationship between nitric oxide(NO) and apoptosis of germ cells in the semen of infertile men. METHODS: Copper-coated cadmium reduction fluorescence assay was used to detect nitrate, the metabolic product of NO. The apoptosis and ultrastructure of germ cells were detected and observed by TdT-mediated dUTP nick end labeling (TUNEL) and transmission electronls microscope (TEM), respectively. RESULTS: In normal control group, concentration of NO and the apoptotic rate of germ cells were (56.83+/-11.65) micromol/L and (4.60+/-1.25)%, respectively; while in inferile group were (128.86+/-23.76) micromol/L and (17.36+/-3.05)%, respectively. The differences in NO concentration and the apoptotic rate of germ cells between the two groups were significant (P<0.01). The concentration of NO was positively correlated with the apoptotic rate of germ cells in infertile group (r=0.96). The apoptotic germ cells showed typical morphology of apoptosis, including nuclear chromatin condensation and margination, nuclear memberane folding, and formation of apoptotic bodies. CONCLUSION: The amount of NO in semen from infertile men has close relationship with apoptotic rate of germ cells. High concentration of NO may result in the increase of germ cell apoptosis rate and lead to male infertility.

Adult↗

PubMed2005

[Sodium nitroprusside facilitates human sperm capacitation and acrosome reaction].

OBJECTIVE: To explore the effect of nitric oxide (NO) on human sperm capacitation and acrosome reaction (AR). METHODS: Different concentrations of sodium nitroprusside (SNP) were added to the sperm suspension from 48 healthy fertile men, and the suspension was incubated in 1 x Earle at 37 degrees C for 1 hour. Progesterone was used to induce AR for 15, 30, 45 and 60 min, and then acid phosphatase (ACP) activity in the suspension before and after capacitation and at different time of AR was measured by p-nitrophenyl sodium phosphate assay. In the meantime, sperm motile parameters were assayed by CASA to observe sperm capacitation and AR. RESULTS: ACP activity and sperm motile parameters increased in the 50 approximately 100 nmol/L NO concentration group, showed no significant variation in the 150 approximately 200 nmol/L group, and decreased in the 250 approximately 300 nmol/L group. CONCLUSION: NO can facilitate sperm capacitation, AR and sperm motile parameters in low concentration and suppress them in high concentration. ACP activity assay of sperm is an objective and reliable method to evaluate sperm capacitation and AR in whole sperm population.

Acid Phosphatase↗

PubMed2005

[Expression patterns of PPARgamma2 in differentiation of mouse embryonic stem (ES) cells into adipocytes].

To investigate the expression patterns of peroxisome proliferator activated receptor2 (PPARgamma2) gene in the differentiation of mouse embryonic stem (ES) cells into adipocytes, mouse ES cells were transfected with the vector of pPPARgamma2-promoter-luciferase, and PPARgamma2 expressions were analyzed by detecting luciferase activities and by detecting the protein expressions using western blotting. The results showed that the gene PPARgamma2 did not express in undifferentiated mouse ES cells and in embryoid bodies (EBs) within the first 2 days of differentiation induction after EB formation, and began to express from the third day of differentiation induction after EB formation to the finish of the differentiation. The gene's expression in differentiated adipocytes was much stronger than that in differentiating preadipocytes. In Conclusion our results reported for the first time the five-step expression patterns of the gene PPARgamma2 during the whole differentiation procedures from mouse ES cells into adipocytes via preadipocytes, and supported the previous studies that PPARgamma2 is a fat-specific gene that expresses only in developed and developing adipose tissues.

Adipocytes↗

PubMed2005

[Clinical analysis of the results in 146 patients with benign tumors or malformations of the oral cavity treated by microwave].

To evaluate the clinical effect of microwave on commonly seen benign tumors or malformations of the oral cavity, 146 patients were randomly selected. There were 78 patients with mucous cyst, 22 patients with papilloma, 24 patients with hemangioma or malformation, 6 patients with lymphatic malformation and 16 patients with epulis. All the patients were treated by ECO-100 microwave. It is concluded that 126 patients were cured (86.3%), 20 patients had good response (13.7%) after treatment.

Hemangioma↗

PubMed2005

[Recombinant adeno-associated viral vector 2-mediated gene transfer of VEGF165 improved porcine chronic myocardial ischemia].

OBJECTIVE: Vectors commonly used for therapeutic angiogenesis such as adenovirus and plasmid had their own limitations. Adenovirus-associated virus (AAV) is a relatively new but probably more ideal vector as it is safe and efficient. We will study the efficiency of recombinant AAV-2 mediated vascular endothelial growth factor165 gene transfer in inducing angiogenesis and arteriogenesis, in improving blood flow and myocardium function in a porcine chronic myocardial ischemic model. METHODS: Chinese experimental minipigs underwent placement of a left circumflex artery aneroid constrictor. Five weeks later, electrocardiogram, coronary angiography and magnetic resonance imaging were performed to confirm occlusion of LCX or ischemia of myocardium in LCX territory. Coronary blood flow, myocardium perfusion and left ventricular wall function were also evaluated. Then the animals were randomized to treatment with rAAV2-VEGF(165) (1 x 10(12) virus genome) or administration of PBS, both by direct myocardial injection. Three and six months after therapy, the animals were evaluated with regard to expression of VEGF(165) Capillary density and arteriole density of the ischemic myocardium, coronary angiography, myocardial perfusion and left ventricular function were also assessed six months after therapy. RESULTS: Five weeks after aneroid occluder implantation, all the animals demonstrated complete or nearly complete occlusion of LCX and perfusion deficiency in LCX territory. Three months after therapy, expression of VEGF(165) mRNA and protein were higher in the VEGF than control group. The difference between the two groups diminished after six months. There was significant increase in capillary density (1404.06 +/- 250.48/mm(2) vs 976.88 +/- 344.79/mm(2), P < 0.05) and arteriole density (167.81 +/- 36.29/mm(2) vs 116.56 +/- 34.48/mm(2), P < 0.05) in VEGF group compared with control. Comparison of myocardial perfusion demonstrated marked differences between the two groups with significant improvement in animals treated with rAAV2-VEGF(165). No significant improvement in left ventricular function was seen in either the VEGF or control group. CONCLUSIONS: Transmyocardial delivery of rAAV2-VEGF(165) resulted in VEGF gene expression for at least three months and stimulated angiogenesis and arteriogenesis in porcine model of chronic myocardial ischemia. Myocardial perfusion was also improved after VEGF gene delivery.

Adenoviridae↗

PubMed2005

[Diagnosis and therapy experience of cerebrospinal rhinorrhea in 15 cases].

OBJECTIVE: To research the diagnosis and treatment of cerebrospinal rhinorrhea. METHOD: Fifteen cerebrospinal rhinorrhea cases were retrospectively analyzed. RESULT: All 15 cases were cured in follow-up from 3 months to 5 years. Different therapeutic approaches were adopted in these cases: conservative therapeutic (4 cases), external nose approach (7 cases), and endoscopic approach (4 cases). CONCLUSION: There are several advantages in adopting endoscopic method such as operating simply, small wound, fixing cerebrospinal rhinorrhea position accurately, and fast post-operation recovering. In some cases adopting external nose approach meanwhile can make up the shortcoming of endoscope and improving operation success probability.

Adolescent↗

PubMed2005

[Clinical analysis of 487 cases with oral and maxillofacial trauma in children].

A retrospective analysis of 487 children with oral and maxillofacial trauma was conducted and the cause, site, type and the age, sex were reviewed. The male and female ratio in children was 1.55:1, the patient children proportion of patients younger than 5 years old was obviously higher than those older than 5 years. Fall accounted for 70.23% among all the causes, the percent age of soft tissue trauma and teeth trauma were 64.89% and 29.89%, the percent age of lip and chin trauma was 56.47%.

Child↗

PubMed2005

[Effect of Huchang Qingfei concentrated pellets on E-cadherin expression in lung tissue of mice infected with Mycoplasma pneumoniae].

OBJECTIVE: To investigate the effects of Huchang Qingfei concentrated pellets on the expression of E-cadherin (E-cd) in the lung tissue from mice infected with Mycoplasma pneumoniae (MP). METHOD: A mice model of Mycoplasmal pneumonia (MPP) was developed by repeatedly intranasal infectious route. Transmission electronic microscope (TEM) and immunohistochemistry stain were performed to observe the pathological changes and expression of E-cd in lung tissues. RESULT: Under TEM it was found that the cellular membrane was ruptured, mitochondria was denatured, crista was broken in the pulmonary cells of the model group; the all above parameters in Huchang medicated group were improved obviously. The immunohistochemistry test showed that strong positive brown stain of E-cd expression was found in the pulmonary epithelial cell membrane and bronchial periphery in the model group, however, in the medicated group, the E-cd expression level in the cellular membrane was decreased and the expression ratio was dropped significantly as compared with the model controls. CONCLUSION: Huchang Qingfei concentrated pellets can inhibit the overexpression of E-cd in the lung tissue of mice with MP-infection, which may be helpful for prevention and treatment of pulmonary injury caused by MPP.

Animals↗

PubMed2004

Development of autoreactive diabetogenic T cells in the thymus of NOD mice.

Type 1 diabetes results from destruction of pancreatic beta cells by beta cell-specific autoreactive T cells in the nonobese diabetic (NOD) mouse. Defects in thymic negative selection are thought to result in failure to delete potential beta cell-reactive T cells, contributing to the development of autoimmune diabetes. We investigated this possibility by comparing the deletion profile of double-positive (DP) thymocytes in NOD mice with diabetes-resistant strains of mice after anti-CD3 Ab treatment to trigger the TCR-mediated signaling pathway. We found that immature NOD CD4+CD8+ DP thymocytes have a lower activation threshold than C57BL/6 and Balb/c thymocytes. This was confirmed by showing that NOD DP thymocytes have a higher level of ERK and JNK phosphorylation. The low activation threshold of immature thymocytes resulted in rapid deletion of strongly activated immature DP thymocytes by negative selection, whereas weakly activated immature thymocytes differentiated more efficiently into CD69+CD3high DP thymocytes by positive selection. SP thymocytes, particularly CD4-CD8+ T cells that were efficiently generated from activated DP thymocytes, could induce severe insulitis and diabetes in NOD.scid mice. We conclude that the development of autoreactive diabetogenic T cells results from inordinate positive selection due to the low activation threshold of DP thymocytes in NOD mice.

Animals↗

PubMed2004

Programmable polymer thin film and non-volatile memory device.

Building on the success of organic electronic devices, such as light-emitting diodes and field-effect transistors, procedures for fabricating non-volatile organic memory devices are now being explored. Here, we demonstrate a novel organic memory device fabricated by solution processing. Programmable electrical bistability was observed in a device made from a polystyrene film containing gold nanoparticles and 8-hydroxyquinoline sandwiched between two metal electrodes. The as-prepared device, which is in a low-conductivity state, displays an abrupt transition to a high-conductivity state under an external bias of 2.8 V. These two states differ in conductivity by about four orders of magnitude. Applying a negative bias of 1.8 V causes the device to return to the low-conductivity state. The electronic transition is attributed to the electric-field-induced charge transfer between the gold nanoparticles and 8-hydroxyquinoline. The transition from the low- to the high-conductivity state takes place in nanoseconds, and is non-volatile, indicating that the device may be used for low-cost, high-density memory storage.

Electric Conductivity↗

PubMed2004

Identification of an invasion regulatory domain within the core protein of syndecan-1.

Among the four members of the syndecan family there exists a high level of divergence in the ectodomain core protein sequence. This has led to speculation that these core proteins bear important functional domains. However, there is little information regarding these functions, and thus far, the biological activity of syndecans has been attributed largely to their heparan sulfate chains. We have previously demonstrated that cell surface syndecan-1 inhibits invasion of tumor cells into three-dimensional gels composed of type I collagen. Inhibition of invasion is dependent on the syndecan heparan sulfate chains, but a role for the syndecan-1 ectodomain core protein was also indicated. To more closely examine this possibility and to map the regions of the ectodomain essential for syndecan-1-mediated inhibition of invasion, a panel of syndecan-1 mutational constructs was generated, and each construct was transfected individually into myeloma tumor cells. The anti-invasive effect of syndecan-1 is dramatically reduced by deletion of an ectodomain region close to the plasma membrane. Further mutational analysis identified a stretch of 5 hydrophobic amino acids, AVAAV (amino acids 222-226), critical for syndecan-1-mediated inhibition of cell invasion. This invasion regulatory domain is 26 amino acids from the start of the transmembrane domain. Importantly, this domain is functionally specific because its mutation does not affect syndecan-1-mediated cell binding to collagen, syndecan-1-mediated cell spreading, or targeting of syndecan-1 to specific cell surface domains. This invasion regulatory domain may play an important role in inhibiting tumor cell invasion, thus explaining the observed loss of syndecan-1 in some highly invasive cancers.

Amino Acid Sequence↗