Biomedical subjects

Ying Hu

Publications and source records attributed to Ying Hu.

At least 37 records · Page 2Linked to original sources

PubMed2006

Defective acute apoptotic response to genotoxic carcinogen in small intestine of APC(Min/+) mice is restored by sulindac.

The effect of APC loss on azoxymethane (AOM)-induced apoptosis and cell proliferation, as well as their regulation by sulindac was examined in colon and small intestine in APC(Min/+) mice. APC(Min/+) mice showed increased epithelial proliferation in all regions, with significant impairment of apoptosis in small intestine, but not in colon. Sulindac administration restored defective apoptosis to normal. As the apoptotic defect occurred at the major site of intestinal tumor formation in APC(Min/+) mice and as it was restored to normal by a proven chemopreventive agent, this defect in apoptosis might be a key biological consequence of APC dysfunction contributing to tumor formation.

Animals↗

PubMed2006

From homoligand- to mixed-ligand- monolayer-protected metal nanoparticles: a scanning tunneling microscopy investigation.

The ligand shell that coats, protects, and imparts a large number of properties to gold nanoparticles is a 2-D self-assembled monolayer wrapped around a 3-D metallic core. Here we present a study of the molecular packing of ligand shells on gold nanoparticles based on the analysis of scanning tunneling microscopy (STM) images. We discuss methods for optimal nanoparticle sample preparation in relation to STM imaging conditions. We show that the packing of a self-assembled monolayer composed solely of octanethiols on gold nanoparticles depends on the particle's diameter with an average headgroup spacing of 5.4 A, which is different from that of similar monolayers formed on flat Au(111) surfaces (5.0 A). In the case of nanoparticles coated with mixtures of ligands-known to phase separate into randomly shaped and ordered domains on flat surfaces-we find that phase separation leads to the formation of concentric, ribbonlike domains of alternating composition. The spacing of these domains depends on the ligand shell composition. We find that, for a given composition, the spacing increases with diameter in a manner characterized by discontinuous transitions at "critical" particle sizes. We discuss possible interpretations for the observed trends in our data.

Journal Article↗

PubMed2006

Cancers as wounds that do not heal: differences and similarities between renal regeneration/repair and renal cell carcinoma.

Cancers have been described as wounds that do not heal, suggesting that the two share common features. By comparing microarray data from a model of renal regeneration and repair (RRR) with reported gene expression in renal cell carcinoma (RCC), we asked whether those two processes do, in fact, share molecular features and regulatory mechanisms. The majority (77%) of the genes expressed in RRR and RCC were concordantly regulated, whereas only 23% were discordant (i.e., changed in opposite directions). The orchestrated processes of regeneration, involving cell proliferation and immune response, were reflected in the concordant genes. The discordant gene signature revealed processes (e.g., morphogenesis and glycolysis) and pathways (e.g., hypoxia-inducible factor and insulin-like growth factor-I) that reflect the intrinsic pathologic nature of RCC. This is the first study that compares gene expression patterns in RCC and RRR. It does so, in particular, with relation to the hypothesis that RCC resembles the wound healing processes seen in RRR. However, careful attention to the genes that are regulated in the discordant direction provides new insights into the critical differences between renal carcinogenesis and wound healing. The observations reported here provide a conceptual framework for further efforts to understand the biology and to develop more effective diagnostic biomarkers and therapeutic strategies for renal tumors and renal ischemia.

Animals↗

PubMed2006

Effect of the spacer group of cationic gemini surfactant on microemulsion phase behavior.

The phase behavior of a system of n-butanol/n-octane/water/cationic gemini surfactant, alkanediyl-alpha,omega-(dimethydodecyl-ammonium bromide)(12-n-12, n=3,4,6), has been investigated by determination the pseudo-ternary phase diagrams. The results have shown that the spacer group of gemini surfactant has a great effect on the phase behavior. The longer the spacer group for the geminis, the more similar the geminis properties to the traditional ones. The mixing content of surfactant and cosurfactant needed for forming microemulsions increases with the geminis' spacer group. The study has also shown that the shorter spacer group of geminis is favorable for the formation of higher ordered surfactant aggregates such as liquid crystals. Furthermore, the microstructures of each region for the studied systems have been investigated by electrical conductivity measurements, UV-visible absorbance spectra of pyrene probe, and dynamic light scattering (DLS). All the results are in accord with each other. DLS makes use of the sensitivity of DLS to structural changes and as expected the hydrodynamic diameter of the microemulsion droplet changes as the transformation of microemulsion microstructures take place. Moreover, the spherical and network structures of microemulsion were further verified by freezing-etching TEM.

Journal Article↗

PubMed2006

Deletion of the inducible 70-kDa heat shock protein genes in mice impairs cardiac contractile function and calcium handling associated with hypertrophy.

BACKGROUND: Hspa1a and Hspa1b genes encode stress-inducible 70-kDa heat shock proteins (Hsp70) that protect cells from insults such as ischemia. Mice with null mutations of both genes (KO) were generated, and their cardiac phenotype was explored. METHODS AND RESULTS: Heart rate and blood pressures were normal in the KO mice. Hearts from KO mice were more susceptible to both functional and cellular damage by ischemia/reperfusion. Cardiac hypertrophy developed in Hsp70-KO mice. Ca2+ transients in cardiomyocytes of KO mice showed a delayed (120%) calcium decline and decreased sarcoplasmic reticulum calcium content. Cell shortening was decreased by 35%, and rates of contraction and relaxation were slower by 40%. These alterations can be attributed to the absence of Hsp70 because viral expression of Hsp70 in KO cultured cardiomyocytes restored these parameters. One mechanism underlying myocyte dysfunction could be decreased SERCA2a expression. This hypothesis was supported by a prolonged calcium decline and decreased SERCA2a protein. Viral SERCA2a expression restored contractility and Ca2+ transients. We examined the involvement of Jun N-terminal kinase (JNK), p38-mitogen-activated protein kinase (p38-MAPK), Raf-1, and extracellular signal-regulated kinase (ERK) in SERCA2a downregulation and the cardiac phenotype of KO mice. Levels of phosphorylated JNK, p38-MAPK, Raf-1, and ERK were elevated in KO hearts. Activation of the Raf-1-ERK pathway in normal cardiomyocytes resulted in decreased SERCA2a. CONCLUSIONS: Absence of Hsp70 leads to dysfunctional cardiomyocytes and impaired stress response of Hsp70-KO hearts against ischemia/reperfusion. In addition, deletion of Hsp70 genes might induce cardiac dysfunction and development of cardiac hypertrophy through the activation of JNK, p38-MAPK, Raf-1, and ERK.

Adenoviridae↗

PubMed2006

Interactions between gemini surfactant alkanediyl-alpha,omega-bis(dodecyldimethylammonium bromide) and polyelectrolyte NaPAA.

Interactions between cationic gemini surfactant alkanediyl-alpha,omega-bis(dodecyldimethylammonium bromide) (12-n-12, n=3,4,6) and oppositely charged polyelectrolyte sodium polyacrylate (NaPAA) in aqueous solution have been investigated by measuring fluorescence, conductivity, UV-vis transmittance, dynamic lighting scattering, and transmission electron microscopy. Micelle-like structure and 12-n-12/NaPAA complex are observed to form due to the electrostatic and hydrophobic interactions, and the effective diameter of the complex reduces with increasing 12-n-12 concentration. The microstructures of 12-n-12/NaPAA solution determined from fluorescence and electron microscopy measurements are in good agreement. The spacer length is found to play an important role in the interactions of 12-n-12 with NaPAA.

Journal Article↗

PubMed2006

A combined effect of the KPNA3 and KPNB3 genes on susceptibility to schizophrenia.

Recent studies suggest that both the KPNB3 gene and the KPNA3 gene in the long arm of chromosome 13 (13q) are associated with schizophrenia. Because these two genes belong to the same family of karyopherins, their combined effect on illness was investigated among 238 Chinese family trios consisting of fathers, mothers and affected offspring with schizophrenia. We detected three single nucleotide polymorphisms (SNPs), including rs626716 at the KPNB3 locus, and rs3782929 and rs3736830 at the KPNA3 locus. The transmission disequilibrium test (TDT) showed allelic association for rs626716 (X2=10.77, P=0.001) and for rs3782929 (X2=4.89, P=0.027) but not for rs3736830 (X2=0.29, P=0.59). Although the conditional test did not show association either for the rs626716-rs3782929 combinations (X2=1.329, d.f.=2, P=0.514) or for the rs626716-rs3736830 combinations (X2=0.606, d.f.=2, P=0.739), the 1-d.f. test showed association for the rs626716(C)-rs3782929(G) combination (X2=10.79, P=0.001) and for the rs626716(C)-rs3736830(G) combination (X2=8.64, P=0.003). The present work suggests that the combination of the KPNA3 gene and the KPNB3 gene may increase a genetic risk for schizophrenia.

Adult↗

PubMed2006

Integrated genome-wide gene expression map and high-resolution analysis of aberrant chromosomal regions in squamous cell lung cancer.

The recognition of recurrent aberrant regions in cancer is important to the discovery of candidate cancer related genes. Here we first constructed a genome-wide gene expression map of squamous lung carcinoma from the Stanford Microarray Database. High-resolution detection of aberrant chromosomal regions was performed by using moving-median method. 84% (27 of 32) of our results were consistent with the previous studies of comparative genomic hybridization or loss of heterozygosity. One overrepresented region in Xq28 was newly discovered to be related to squamous cell lung carcinoma. These observations could be of great interest for further studies.

Carcinoma, Squamous Cell↗

PubMed2006

Phase behavior of polyampholytes from charged hard-sphere chain model.

A molecular thermodynamic theory is developed for polyampholytes from the coarse-grained charged hard-sphere chain model. The phase behavior of polyampholytes with variations in sequence and chain length is satisfactorily predicted by the theory, consistent with simulation results and experimental observations. At a fixed chain length, the phase envelope expands as the sequence of charge distribution becomes less random. With increasing chain length, the phase envelope expands for diblock and random polyampholytes, but shrinks for zwitterionic polyampholytes. The predicted critical temperature, density, and pressure exhibit scaling relations with chain length for all the three (diblock, random, and zwitterionic) polyampholytes.

Journal Article↗

PubMed2006

[Detection of expression of p53, p16, and cyclooxygenase 2 in pancreatic cancer by tissue microarray and correlation among these three genes].

OBJECTIVE: To detect the expression of tumor suppressor protein p53, cyclin-dependent kinase inhibitor p16, and cyclooxygenase 2 (COX-2) in pancreatic cancer by tissue microarray and investigate the correlation among these three genes. METHODS: 104 specimens of tissues, including pancreatic cancer tissue, non-cancer tissues not more than 1.5 cm from the cancer, and normal tissues, underwent microarray examination and immunohistochemistry to detect the expression of p53, p16, and COX-2. The correlation among these 3 genes was analyzed. RESULTS: p53, p16, and COX-2 were all significantly highly expressed in the cancerous tissues in comparison with other tissues. P53 and p16 were both significantly correlated with COX-2 (both P < 0.05), however, there was not a correlation between p53 and p16 (P > 0.05). There was a reciprocal relationship between p53 and COX-2 (P < 0.05, OR = 19.686) influencing the pathogenesis of pancreatic cancer. CONCLUSION: Tissue microarray technique is effective method to detect multiple gene protein expression. Pathogenesis of pancreatic cancer is associated with p53, p16, and COX-2.

Adolescent↗

PubMed2006

SEBS aggregate patterning at a surface studied by atomic force microscopy.

The morphologies of films spin coated from dilute block copolymer solution onto a mica substrate were studied by atomic force microscopy (AFM). Variables of interest were the polymer concentration, solvent, heating temperature, aging, and ultrasonic effect. It is shown that the solution concentration is the predominant factor in determining the shape of the aggregates displayed from spheres and rods to irregular patches with increasing concentration. The solubility parameter of the solvent plays an important role in modifying the distribution and the size of clusters at the surface. The structures of the aggregates at the surface are metastable, which could evolve with temperature from rodlike aggregates into regular stripes when annealed at a temperature higher than the order-disorder transition temperature of SEBS, whereas those in solution could evolve with aging and ultrasonic treatment into a more stable network structure.

Aluminum Silicates↗

PubMed2006

Phase behavior of gemini surfactant hexylene-1,6-bis(dodecyldimethylammonium bromide) and polyelectrolyte NaPAA.

The phase behavior of aqueous mixtures of gemini surfactant hexylene-1,6-bis(dodecyldimethylammonium bromide) (12-6-12) and oppositely charged polyelectrolyte sodium polyacrylate (NaPAA) has been studied experimentally. Compared to the mixtures of the traditional surfactant dodecyltrimethylammonium bromide (DTAB) and NaPAA, the gel phase region in the 12-6-12/NaPAA solution is larger. Element analysis reveals that NaPAA in the gel phase tends to replace the counterions of surfactant micelle and to release its own counterions. Spherical aggregates are observed in either top or bottom gel phase as detected by transmission electron microscopy. The addition of sodium bromide (NaBr) leads to a decrease in the gel phase region and the occurrence of a new cream phase.

Journal Article↗

PubMed2006

Infectious diseases - a global challenge.

Infectious diseases represent a continuous and increasing threat to human health and welfare. Due to emerging diseases, increasing resistances, international travelling, and the risk of bioterroristic attacks, infectious diseases concern the whole world and can only be combated by internationally coordinated and interdisciplinary approaches. When assessing the worldwide publication activities on infectious diseases in the years 1994-2004 accessible via the ISI Science Citation Index Expanded, an overall increase by 24% can be monitored. Furthermore, it becomes evident that highest research priorities are given to HIV/AIDS, hepatitis C, tuberculosis, respiratory infections, and sepsis. Ten countries - including the USA, the UK, France, Germany, and Japan - contributed to more than 80% of these publications; nation-specific research priorities focusing on the current problems in the respective country can be estimated. Countries with the highest disease burdens are still not given the opportunity to contribute adequately to the scientific field. Based on our data, relatively increasing publication activities include those on respiratory infections, tuberculosis, malaria, hepatitis, and sepsis, whereas decreasing activities were determined for AIDS, diarrhoea, meningitis, schistosomiasis, and other diseases. Accordingly, the prevalence of many infectious diseases occurring in tropical countries is not clearly reflected in the worldwide publication activities.

Bibliometrics↗

PubMed2006

A simple approach to the synthesis of silver nanowires by hydrothermal process in the presence of gemini surfactant.

Silver nanowires were synthesized by the hydrothermal route in aqueous solution of gemini surfactant 1,3-bis(cetyldimethylammonium) propane dibromide (16-3-16) at a relatively low temperature. The as-prepared silver nanowires were characterized by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), transmission electron microscope (TEM), electron diffraction (ED), and UV-vis absorption spectrum. The obtained silver nanowires are of high aspect ratios with an average diameter of approximately 30 nm and length ranging from several to tens of micrometers.

Journal Article↗

PubMed2006

Intermediacy of poly(L-proline) II and beta-strand conformations in poly(L-lysine) beta-sheet formation probed by temperature-jump/UV resonance Raman spectroscopy.

Ultraviolet resonance Raman spectroscopy (UVRR) in combination with a nanosecond temperature jump (T-jump) was used to investigate early steps in the temperature-induced alpha-helix to beta-sheet conformational transition of poly(L-lysine) [poly(K)]. Excitation at 197 nm from a tunable frequency-quadrupled Ti:sapphire laser provided high-quality UVRR spectra, containing multiple conformation-sensitive amide bands. Although un-ionized poly(K) (pH 11.6) is mainly alpha-helical below 30 degrees C, there is a detectable fraction (approximately 15%) of unfolded polypeptide, which is mainly in the poly(L-proline) II (PPII) conformation. However, deviations from the expected amide I and II signals indicate an additional conformation, suggested to be beta-strand. Above 30 degrees C un-ionized poly(K) forms a beta-sheet at a rate (minutes) which increases with increasing temperature. A 22-44 degrees C T-jump is accompanied by prompt amide I and II difference signals suggested to arise from a rapid shift in the PPII/beta-strand equilibrium. These signals are superimposed on a subsequently evolving difference spectrum which is characteristic of PPII, although the extent of conversion is low, approximately 2% at the 3 micros time limit of the experiment. The rise time of the PPII signals is approximately 250 ns, consistent with melting of short alpha-helical segments. A model is proposed in which the melted PPII segments interconvert with beta-strand conformation, whose association through interstrand H-bonding nucleates the formation of beta-sheet. The intrinsic propensity for beta-strand formation could be a determinant of beta-sheet induction time, with implications for the onset of amyloid diseases.

Amyloid↗

PubMed2006

Expression of survivin, CDK4, Ki-67 and clinical significance in pediatric acute leukemia.

The expression of Survivin, CDK4 and Ki-67 and the clinical significance in pediatric acute leukemia (AL) were investigated. The expression of Survivin, CDK4 and Ki-67 proteins was detected by using immunohistochemical assay in 37 children with AL and 10 children with normal bone marrow as controls. The positive expression rate of Survivin, CDK4 and Ki-67 was 45.9 %, 56.8 %, and 40.5 % respectively in 37 AL children, which was significantly higher than in control group accordingly (P<0.05). The expression of Survivin was positively correlated with CDK4 (P=0.007) and Ki-67 (P=0.008). In conclusion, all Survivin, CDK4 and Ki-67 proteins are over-expressed in pediatric AL and involved in the modulation of apoptosis and proliferation in pediatric AL.

Adolescent↗

PubMed2006

The tumor kinetics of multiple myeloma following autologous stem cell transplantation as assessed by measuring serum-free light chains.

In multiple myeloma, changes in serum-free immunoglobulin light chains (FLC) are a more rapid indicator of treatment response than intact immunoglobulin due to their shorter serum half-life. The present study analysed the changes in serum FLC after autologous peripheral blood stem cell transplantation (PBSCT) in 19 patients. The majority of myeloma patients (18 of 19) undergoing PBSCT had a rapid fall in FLC concentrations. In all 11 of 19 patients with raised tumor FLC, it fell within 48 h following high-dose melphalan. In patients with monoclonal intact immunoglobulin, the tumor FLC fell quicker (median half-life 4.3 days) than the monoclonal intact immunoglobulin (median half-life 14 days). FLC recovery occurred after (13 of 19) or around the time of neutrophil engraftment (6 of 19). With a median follow up of 220 days post-transplant, 16 of 19 patients have a normal FLC ratio and 3 of 19 have an elevated tumor FLC/abnormal ratio. FLC assays provided a sensitive monitor of changes in tumor and non-tumor plasma cells after PBSCT. This assay is potentially valuable as a marker of chemosensitivity, as an indicator of residual tumor and indicated time to lymphocyte engraftment. Further follow-up is required to ascertain whether differences in the kinetics of FLC responses have any prognostic clinical utility.

Adult↗

PubMed2006

The production of reactive oxygen species and the mitochondrial membrane potential are modulated during onion oil-induced cell cycle arrest and apoptosis in A549 cells.

Protective effects of Allium vegetables against cancers have been shown extensively in experimental animals and epidemiologic studies. We investigated cell proliferation and the induction of apoptosis by onion oil extracted from Allium cepa, a widely consumed Allium vegetable, in human lung cancer A549 cells. GC/MS analysis suggested that propyl sulfides but not allyl sulfides are major sulfur-containing constituents of onion oil. Onion oil at 12.5 mg/L significantly induced apoptosis (13% increase of apoptotic cells) as indicated by sub-G1 DNA content. It also caused cell cycle arrest at the G2/M phase; 25 mg/L onion oil increased the percentage of G2/M cells almost 6-fold compared with the dimethyl sulfoxide control. The action of onion oil may occur via a reactive oxygen species-dependent pathway because cell cycle arrest and apoptosis were blocked by the antioxidants N-acetylcysteine and exogenous glutathione. Marked collapse of the mitochondrial membrane potential suggested that dysfunction of the mitochondria may be involved in the oxidative burst and apoptosis induced by onion oil. Expression of phospho-cdc2 and phospho-cyclin B1 were downregulated by onion oil, perhaps accounting for the G2/M arrest. Overall, these results suggest that onion oil may exert chemopreventive action by inducing cell cycle arrest and apoptosis in tumor cells.

Apoptosis↗