Biomedical subjects

Li Zhu

Publications and source records attributed to Li Zhu.

At least 91 records · Page 5Linked to original sources

PubMed2005

[The effect of fungi in the pathogenesis of nasal polyps and chronic rhinosinusitis].

OBJECTIVE: To study the effect of fungi in the pathogenesis of nasal polyps and chronic rhinosinusitis (CRS). METHOD: This study were divided two groups, the first was the experimental group: Nasal mucus membrane and nasal polyps were collected from patients with CRS (with and without polyps), and the second was the control group, nasal mucus were collected from OHc. Fungal-specific PCR were performed on each sample. The anther was used 0.9% sol sodium chloride to wash the autopsy tissues 5 times, and then PCR analysis was performed. chi-squared analysis was used to test for statistical difference between these groups. RESULT: PCR technique detected fungal DNA were 89.2% and 89.4% in nasal polyps and nasal mucous membrane respectively, and 66.7% in normal control subjective. There were statistically significant difference in these groups. After using 0.9% sol sodium chloride to wash the autopsy tissues, the fungi's positive rate was dropped. CONCLUSION: Fungi was important in the pathogenesis of nasal polyps and CRS.

Adolescent↗

PubMed2005

[Spectra of rare earth complexes RE(Et2 dtc),3 (phen)].

The ternary solid complexes RE(Et2dtc)3 (phen) (RE=La, Pr, Nd, Sm-Er) were synthesized with sodium diethyldithiocarbamate (NaEt2 dtc x 3H2O), 1,10-phenanthroline (o-phen x H2O) and hydrated lanthanide chlorides in absolute ethanol by improved reported method. IR results revealed that RE3+ coordinated with sulfur atoms of NaEt2 dtc and nitrogen atoms of o-phen. As for UV spectrum of the complexes, energy transfer between o-phen and RE3+ was the primary process, and the main absorption peaks showed a slight red shift compared to that of o-phen; FS spectrum, as a comparison, showed that the complexes Sm (Et2 dtc)3 (phen) and Eu(Et2dtc)3 (phen) have a higher efficiency of intermolecular energy transfer and a stronger fluorescence character.

English Abstract↗

PubMed2004

Functional characterization of rhodopsin monomers and dimers in detergents.

Rhodopsin (Rho) is a G protein-coupled receptor that initiates phototransduction in rod photoreceptors. High expression levels of Rho in the disc membranes of rod outer segments and the propensity of Rho to form higher oligomeric structures are evident from atomic force microscopy, transmission electron microscopy, and chemical cross-linking experiments. To explore the structural and functional properties of Rho in n-dodecyl-beta-maltoside, frequently used to purify heterologously expressed Rho and its mutants, we used gel filtration techniques, blue native gel electrophoresis, and functional assays. Here, we show that in micelles containing n-dodecyl-beta-maltoside at concentrations greater than 3 mM, Rho is present as a single monomer per detergent micelle. In contrast, in 12 mM 3-[(3-cholamidopropyl)dimethyl-ammonio]-1-propanesulfonate (CHAPS), micelles contain mostly dimeric Rho. The cognate G protein transducin (Gt) appears to have a preference for binding to the Rho dimer, and the complexes fall apart in the presence of guanosine 5'-3-O-(thio)triphosphate. Cross-linked Rho dimers release the chromophore at a slower rate than monomers and are much more resistant to heat denaturation. Both Rho(*) monomers and dimers are capable of activating Gt, and both of them are phosphorylated by Rho kinase. Rho expressed in HEK293 cells is also readily cross-linked by a bifunctional reagent. These studies provide an explanation of how detergent influences the oligomer-dimermonomer equilibrium of Rho and describe the functional characterization of Rho monomers and dimers in detergent.

Animals↗

PubMed2004

A naturally occurring mutation of the opsin gene (T4R) in dogs affects glycosylation and stability of the G protein-coupled receptor.

Rho (rhodopsin; opsin plus 11-cis-retinal) is a prototypical G protein-coupled receptor responsible for the capture of a photon in retinal photoreceptor cells. A large number of mutations in the opsin gene associated with autosomal dominant retinitis pigmentosa have been identified. The naturally occurring T4R opsin mutation in the English mastiff dog leads to a progressive retinal degeneration that closely resembles human retinitis pigmentosa caused by the T4K mutation in the opsin gene. Using genetic approaches and biochemical assays, we explored the properties of the T4R mutant protein. Employing immunoaffinity-purified Rho from affected RHO(T4R/T4R) dog retina, we found that the mutation abolished glycosylation at Asn(2), whereas glycosylation at Asn(15) was unaffected, and the mutant opsin localized normally to the rod outer segments. Moreover, we found that T4R Rho(*) lost its chromophore faster as measured by the decay of meta-rhodopsin II and that it was less resistant to heat denaturation. Detergent-solubilized T4R opsin regenerated poorly and interacted abnormally with the G protein transducin (G(t)). Structurally, the mutation affected mainly the "plug" at the intradiscal (extracellular) side of Rho, which is possibly responsible for protecting the chromophore from the access of bulk water. The T4R mutation may represent a novel molecular mechanism of degeneration where the unliganded form of the mutant opsin exerts a detrimental effect by losing its structural integrity.

Alleles↗

PubMed2004

CXCR4 and CXCL12 (SDF-1) in prostate cancer: inhibitory effects of human single chain Fv antibodies.

PURPOSE: Metastasis is a major cause of morbidity in prostate cancer (PCa). Several studies have shown that the chemokine receptor CXCR4 and its ligand, CXCL12 (stromal cell-derived factor-1), regulate tumor cell metastasis to specific organs. Recently, it was demonstrated that CXCL12 enhances PCa cell adhesion, migration, and invasion, implicating CXCR4 in PCa metastasis. In this study, we examined the inhibitory effects of anti-CXCR4 antibodies on CXCL12-mediated PCa cell activities. EXPERIMENTAL DESIGN: We developed fully human single chain Fv antibodies (scFv), Ab124 and Ab125, against CXCR4 using the yeast two-hybrid system. We performed immunofluorescent staining, flow cytometry, and ELISA-binding assays to measure scFv binding to PCa cells. We also examined the effects of scFv on CXCL12-mediated calcium mobilization, cell migration, and invasion. RESULTS: Our results confirmed that PCa cell lines express cell-surface CXCR4. Real-time quantitative reverse transcription-PCR and immunohistochemical staining also verified that CXCR4 is expressed in primary cultures of prostate epithelial cells from adenocarcinomas and in human prostate tissues. Ab124 and Ab125 demonstrated specific binding to PCa cell lines by flow cytometry and in binding assays. Preincubation with scFv resulted in significant reduction of CXCL12-induced calcium mobilization in PC-3 and LNCaP cells. Ab124 and Ab125 also inhibited PCa cell migration toward CXCL12, as well as invasion through extracellular matrix gels. CONCLUSIONS: Ab124 and Ab125 inhibit CXCL12-mediated cellular activities by binding the receptor CXCR4. Recombinant scFv are an efficient mode of targeting tumor antigens. Considering the high incidence of PCa, the development of fully human scFv may be a useful therapeutic approach in the prevention and treatment of PCa metastasis.

Breast Neoplasms↗

PubMed2004

Advanced glycation endproduct (AGE) receptor 1 is a negative regulator of the inflammatory response to AGE in mesangial cells.

Advanced glycation endproducts (AGE) contribute to kidney disease due to diabetes or aging by means of mesangial cell (MC) receptors, such as the receptor for AGE (RAGE), which promote oxidant-stress-dependent NF-kappaB activation and inflammatory gene expression. MC also express scavenger receptors SR-I and SR-II and AGE receptors 1, 2, and 3 (AGE-R1, -R2, and -R3), some of which are linked to AGE turnover. Because AGE-R1 expression is found suppressed in severe diabetic kidney disease, as other receptors increase, we investigated whether his molecule has a protective role against AGE-induced MC injury. A stable murine MC line overexpressing AGE-R1 (R1-MC) was generated, exhibiting a 1.8- to 2.7-fold increase in (125)I-AGE-specific binding, uptake, and degradation, compared with mock-MC. However, AGE-stimulated NF-kappaB activity and mitogen-activated protein kinase (MAPK) (p44/42) phosphorylation were found markedly suppressed in R1-MC. Additionally, AGE-stimulated macrophage chemotaxis protein 1 and RAGE overexpression were abolished in R1-MC. The effect of R1 on RAGE signaling was investigated after overexpressing RAGE in Chinese hamster ovary cells, which lack RAGE. AGE stimulation elicited NF-kappaB and MAPK activities in RAGE-Chinese hamster ovary cells; however, after cotransfection with R1, these responses were suppressed. Also, after silencing endogenous R1 in wild-type MC by R1 small interfering RNA, AGE-mediated MAPK/p44/42 activation exceeded by >2-fold that of mock-MC, consistent with loss of the activation-inhibitory properties of native AGE-R1. AGE-R1, although enhancing AGE removal, is also a distinct receptor in that it suppresses AGE-mediated MC inflammatory injury through negative regulation of RAGE, a previously uncharacterized pathway that may protect renal and other tissue injury due to diabetes and aging.

Animals↗

PubMed2004

Cell transport via electromigration in polymer-based microfluidic devices.

Electrokinetic transport of Escherichia coli and Saccharomyces cerevisiae (baker's yeast) cells was evaluated in microfluidic devices fabricated in pristine and UV-modified poly(methyl methacrylate)(PMMA) and polycarbonate (PC). Chip-to-chip reproducibility of the cell's apparent mobilities (micro(app)) varied slightly with a RSD of approximately 10%. The highest micro(app) for baker's yeast cells was observed in UV-modified PC with 0.5 mM PBS (pH = 7.4), and the lowest was measured in pristine PMMA with 20 mM PBS (pH = 7.4). Baker's yeast in all devices migrated toward the cathode because of their smaller electrophoretic mobility compared to the EOF. In 0.5 mM and 1 mM PBS, E. coli cells migrated toward the anode in all cases, opposite to the direction of the EOF due to their larger electrophoretic mobility. E. coli cells in 20 mM PBS migrated toward the cathode, which indicated that the electrophoretic mobility of E. coli cells decreased at higher ionic strengths. Observed differential migrations of E. coli and baker's yeast cells in appropriately prepared polymer microchips were used as the basis for selective introduction into microfluidic devices of only one type of cell. As a working model, experiments were performed with E. coli and RBCs (red blood cells). RBCs migrated toward the cathode in pristine PMMA with 1 mM and 20 mM PBS (pH = 7.4), opposite to the direction of the E. coli cells. By judicious choice of the buffer concentration in which the cell suspension was prepared and the polymer material, RBCs or E. coli cells were selectively introduced into the microdevice, which was monitored via laser backscatter signals.

Cells↗

PubMed2004

Multiplexed fluorescence detection in microfabricated devices with both time-resolved and spectral-discrimination capabilities using near-infrared fluorescence.

We examined the feasibility of using a two-color time-resolved detection scheme with microdevices for DNA sequencing applications. A home-built dual-color optical-fiber-based time-resolved near-infrared (IR) fluorescence microscope successfully coupled lifetime discrimination with color discrimination, increasing fluorescence multiplexing capabilities. The instrument was constructed by using two pulsed-diode lasers (680/780-nm excitation) and two avalanche photodiodes as the basic building blocks. The data were processed using electronics configured in a time-correlated single-photon counting format. The use of near-IR fluorescence detection greatly simplified the hardware and allowed low detection limits (< 0.1nM). We examined the separation of a single-base tract on a microchip and compared the performance with that of conventional capillary gel electrophoresis. The microchip was fabricated in glass and contained an effective separation length of 7.0 cm. It was found that, without incorporating a solid-phase reversible immobilization cleanup procedure, the calculated lifetime of the dye label on the microchip was longer and the standard deviation was larger than those of the same sample analyzed using capillary electrophoresis. Using cleanup steps, the accuracy and precision of the measurements improved. Lifetimes of four near-IR dyes (AlexaFluor680, IRD700, IRD800, and IRD40) used in this study were determined to be 986 ps (RSD=2.1%), 1551 ps (RSD=1.8%), 520 ps (RSD=3.3%), and 788 ps (RSD=4.9%), respectively, in a microchannel filled with poly(dimethylacrylamide) (POP-6) gel. The lifetimes calculated using maximum likelihood estimators provided favorable precision on the microchip, where small numbers of photocounts were collected. An M13mp18 template was sequenced on the microchip using a two-color two-lifetime format with POP-6 as the sieving polymer. Read lengths of 294 bp with calling accuracies of 90.8 and 83.7% were achieved in each color channel. The relatively low calling accuracy and the short read length resulted primarily from the short separation channel, which yielded low electrophoretic resolution.

DNA↗

PubMed2004

Her2/neu expression predicts the response to antiaromatase neoadjuvant therapy in primary breast cancer: subgroup analysis from celecoxib antiaromatase neoadjuvant trial.

PURPOSE: Many studies suggest that Her2/neu play an important role in neoadjuvant endocrine therapy. This study aimed to determine whether the level of Her2/neu expression in advanced breast cancer changes after antiaromatase neoadjuvant treatment, as well as to identify the relationship between Her2/neu expression and response to this kind of therapy. EXPERIMENTAL DESIGN: Thirty-six postmenopausal patients with hormonal receptor-positive primary breast cancer were included in a study of three monthly cycles of neoadjuvant endocrine therapy with either Aromasin (25 mg daily) or Femara (2.5 mg daily). Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) for Her2/neu were conducted both on pretreatment biopsies and surgical tumors. RESULTS: Using IHC, 5 of 36 (13.9%) of the patients had a Her2/neu overexpression after treatment, as compared with 16 of 36 (44.4%) before. Meanwhile, there was no change in 21 (58.3%) patients, and through FISH, there was a change from amplification to no amplification in 15 (41.7%) patients. The response rate to the treatment was 75% for Her2/neu (+) tumors and 35% for Her2/neu (-) tumors (P = 0.017) while FISH was performed. The response rate was also significantly affected by the decrease in Her2/neu status after the treatment, with 73% of the tumors showing decreased Her2/neu expression and with 38% of the tumors showing no change of Her2/neu expression (P = 0.037). CONCLUSIONS: Using both IHC and FISH, advanced breast cancers show statistical evidence of decreasing incidence of Her2/neu expression after antiaromatase neoadjuvant treatment. Our data also suggest that Her2/neu expression and its change during the treatment might be predictive markers for this kind of therapy.

Aged↗

PubMed2004

High levels of dietary advanced glycation end products transform low-density lipoprotein into a potent redox-sensitive mitogen-activated protein kinase stimulant in diabetic patients.

BACKGROUND: LDL modification by endogenous advanced glycation end products (AGEs) is thought to contribute to cardiovascular disease of diabetes. It remains unclear, however, whether exogenous (diet-derived) AGEs influence glycoxidation and endothelial cell toxicity of diabetic LDL. METHODS AND RESULTS: Twenty-four diabetic subjects were randomized to either a standard diet (here called high-AGE, HAGE) or a diet 5-fold lower in AGE (LAGE diet) for 6 weeks. LDL pooled from patients on HAGE diet (Db-HAGE-LDL) was more glycated than LDL from the LAGE diet group (Db-LAGE-LDL) (192 versus 92 AGE U/mg apolipoprotein B) and more oxidized (5.7 versus 1.5 nmol malondialdehyde/mg lipoprotein). When added to human endothelial cells (ECV 304 or human umbilical vein endothelial cells), Db-HAGE-LDL promoted marked ERK1/2 phosphorylation (pERK1/2) (5.5- to 10-fold of control) in a time- and dose-dependent manner compared with Db-LAGE-LDL or native LDL. In addition, Db-HAGE-LDL stimulated NF-kappaB activity significantly in ECV 304 and human umbilical vein endothelial cells (2.3-fold above baseline) in a manner inhibitable by a MEK inhibitor PD98059 (10 micromol/L), the antioxidant N-acetyl-l-cysteine, NAC (30 mmol/L), and the NADPH oxidase inhibitor DPI (20 micromol/L). In contrast to Db-LAGE-LD and native LDL, Db-HAGE-LDL induced significant soluble vascular cell adhesion molecule-1 production (2.3-fold), which was blocked by PD98059, NAC, and DPI. CONCLUSIONS: Exposure to daily dietary glycoxidants enhances LDL-induced vascular toxicity via redox-sensitive mitogen-activated protein kinase activation. This can be prevented by dietary AGE restriction.

Acetylcysteine↗

PubMed2004

Intratumoral administration of dendritic cells overexpressing CCL21 generates systemic antitumor responses and confers tumor immunity.

To achieve in situ tumor antigen uptake and presentation, intratumoral administration of ex vivo-generated, gene-modified murine bone marrow-derived dendritic cells (DC) was used in a murine lung cancer model. To attract mature host DC and activated T cells at the tumor site, the DC were transduced with an adenoviral vector expressing secondary lymphoid tissue chemokine (CCL21/SLC). Sixty percent of the mice treated with 10(6) DC-AdCCL21 intratumorally (7-10 ng/ml/10(6) cells/24 h of CCL21) at weekly intervals for 3 weeks showed complete tumor eradication, whereas only 25% of mice had complete resolution of tumors when mice were treated with fibroblasts expressing CCL21. In contrast only 12% of the mice treated with unmodified or control vector modified DC (DC-AdCV) showed complete tumor eradication. DC-AdCCL21 administration led to increases in the CD4(+), CD8(+), and CD3(+)CXCR3(+) T cells, as well as DC expressing CD11c(+) DEC205(+). CD4(+)CD25(+) T-regulatory cells infiltrating the tumors were markedly reduced after DC-AdCCL21 therapy. The tumor site cellular infiltrates were accompanied by the enhanced elaboration of granulocyte macrophage colony-stimulating factor, IFN-gamma, MIG/CXCL9, IP-10/CXCL10, and interleukin 12, but decreases in the immunosuppressive mediators transforming growth factor beta and prostaglandin E(2). DC-AdCCL21-treated tumor-bearing mice showed enhanced frequency of tumor-specific T lymphocytes secreting IFN-gamma, and tumor protective immunity was induced after DC-AdCCL21 therapy. In vivo depletion of IP-10/CXCL10, MIG/CXCL9, or IFN-gamma significantly reduced the antitumor efficacy of DC-AdCCL21. These findings provide a strong rationale for the evaluation of DC-AdCCL21 in cancer immunotherapy.

Adenoviridae↗

PubMed2004

Regulatory regions and critical residues of NOD2 involved in muramyl dipeptide recognition.

Multiple genetic variants of CARD15/NOD2 have been associated with susceptibility to Crohn's disease and Blau syndrome. NOD2 recognizes muramyl dipeptide (MDP) derived from bacterial peptidoglycan (PGN), but the molecular basis of recognition remains elusive. We performed systematic mutational analysis to gain insights into the function of NOD2 and molecular mechanisms of disease susceptibility. Using an archive of 519 mutations covering approximately 50% of the amino-acid residues of NOD2, the essential regulatory domains and specific residues of NOD2 involved in recognition of MDP were identified. The analysis revealed distinct roles for N-terminal and C-terminal leucine-rich repeats (LRRs) in the modulation of NOD2 activation and bacterial recognition. Within the C-terminal LRRs, variable residues predicted to form the beta-strand/betaturn structure were found to be essential for the response to MDP. In addition, we analyzed NOD1, a NOD2-related protein, revealing conserved and nonconserved amino-acid residues involved in PGN recognition. These results provide new insights into the molecular function and regulation of NOD2 and related NOD family proteins.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed2004

Cryopyrin-induced interleukin 1beta secretion in monocytic cells: enhanced activity of disease-associated mutants and requirement for ASC.

Several autoinflammatory disorders are associated with missense mutations within the nucleotide-binding oligomerization domain of cryopyrin. The mechanism by which cryopyrin mutations cause inflammatory disease remains elusive. To understand the molecular bases of these diseases, we generated constructs to express three common cryopyrin disease-associated mutations, R260W, D303N, and E637G, and compared their activity with that of the wild-type protein. All cryopyrin mutant proteins tested were found to induce potent NF-kappaB activity when compared with the wild-type protein. This activation was dependent on the expression of ASC, an adaptor protein previously suggested to mediate cryopyrin signaling. When the disease-associated mutants were expressed in monocytic THP-1 cells (which express endogenous ASC), each induced spontaneous IL-1beta secretion, whereas wild-type protein did not. In the absence of stimuli, wild-type cryopyrin was unable to bind to ASC, whereas the three mutants coimmunoprecipitated with ASC, suggesting a mechanism involved in the constitutive activation of mutant proteins. The induction of cryopyrin activity by enforced oligomerization in THP-1 cells resulted in ASC binding and the secretion of IL-1beta, an effect that was abolished by the inhibition of ASC expression with small interfering RNAs. Thus, cryopyrin-mediated IL-1beta secretion requires ASC in monocytic cells. Further, these results indicate that cryopyrin disease-associated mutants are constitutively active and able to induce NF-kappaB activation and IL-1beta secretion at least in part by an increased ability to interact with ASC.

Apoptosis↗

PubMed2004

Sellmeier's equation and the expression of the thermal refractive-index coefficient for a Nd0.007Gd0.993VO4 crystal.

The principal refractive indices of a Nd0.007Gd0.993VO4 crystal for wavelengths of 0.488, 0.6328, 1.064, 1.0795, and 1.3414 microm under the temperature range of 20-170 degrees C are measured by the autocollimation method, and the Sellmeier's equation and the expression of the thermal refractive-index coefficient are then obtained. The reliability of these results is checked by comparing the calculated values with the measured values for the measured wavelengths and the temperature region, as well as with the published values by Studenikin et al. [Quantum Electron. 25, 1162-1165 (1995)] for wavelengths of 0.491, 0.546, 0.578, 0.632, 0.808, and 1.062 microm at 20 degrees C. In addition, the birefringence and the thermal coefficient of the birefringence were obtained by measured results. The results show that the birefringence is larger than that of a YVO4 crystal and that the thermal coefficient of birefringence is less than that of a YVO4 crystal. Therefore it can be expected that the GdVO4 crystal is not only an excellent laser crystal but also an excellent birefringent crystal used in a modern optical transmission system as a passive fiber-optic component.

Journal Article↗

PubMed2004

Comparative in vitro and in vivo genotoxicities of 7H-benzo[c]fluorene, manufactured gas plant residue (MGP), and MGP fractions.

Manufactured gas plant residue (MGP) is a complex mixture of polycyclic aromatic hydrocarbons (PAHs) that is tumorigenic in the lungs of mice. This study compared the relative genotoxicity of 7H-benzo[c]fluorene (BC), a PAH component of MGP, with MGP and MGP fractions in order to assess the contribution of BC to the genotoxicity of MGP. An MGP sample was separated into seven fractions (F1-F7) using silica gel column chromatography with petroleum ether (PE) followed by PE:acetone (99:1 v/v, then 98:2). PAHs were quantified using gas chromatography/mass spectrometry. An aliquot of F2, the fraction with the highest BC concentration and highest weighted mutagenic activity in Salmonella typhimurium strain TA98, was further separated using silica gel thin-layer chromatography with hexane. The first F2 subfraction, sF2-a, was enriched in BC and coeluting compounds and contained 35,000 ppm BC and 216,109 ppm carcinogenic PAHs (cPAHs, the sum of seven PAHs categorized by the U.S. EPA as class B2 carcinogens). The second F2 subfraction, sF2-b, contained a ninefold lower concentration of BC, with 3,900 ppm BC and 45,216 ppm cPAHs. Female ICR mice received topical application of crude MGP, crude MGP spiked with analytical-grade BC, F2, sF2-a, sF2-b, or analytical-grade BC. DNA adduct levels were analyzed by nuclease P1-enhanced (32)P-postlabeling. In lung DNA of mice receiving 0.48 or 3.0 mg/mouse, net total RAL x 10(9) values were F2, 30.8 and 87.2; sF2-a, 24.8 and 106.7; and sF2-b, 19.6 and 151.0, respectively. Mice dosed with 0.10 mg analytical-grade BC (the mass of BC in 3.0 mg sF2-a) exhibited a net total RAL x 10(9) value of 7.03 in lung DNA. This was equal to approximately 7% of the total RAL x 10(9) value produced by 3.0 mg sF2-a. Thus, although BC appears to make an appreciable contribution to pulmonary adduct formation, the results suggest that MGP components other than BC play an important role in lung DNA adduct formation following topical MGP administration.

Animals↗

PubMed2004

Expression of MDM2 protein and mRNA in condyloma acuminata.

In order to investigate the role of murine double minute 2 (MDM2) in cell proliferation and carcinogenesis in condyloma acuminatum (CA), immunohistochemistry and in situ hybridization were used to detect the expression of MDM2 protein and mRNA in normal skin and skin lesions of CA of vulva. PCR was also used to detect HPV types. The results showed that in 32 observed CA specimens, the expression of MDM2 protein and mRNA was detected in 18 (56.25%) and 22 (68.75%) respectively, while the co-expression of MDM2 protein and mRNA was found in 14. PCR results revealed that HPV6/11 and HPV16/18 subtypes were shown in 28(87.5%) and 4 (12.5%) respectively out of 32 CA specimens. Out of the 18 positive specimens expressing MDM2 protein, HPV6/11 subtypes were shown in 15 and HPV16/18 subtypes in 3. In 22 positive specimens expressing MDM2 mRNA, HPV6/11 subtypes were shown in 18 and HPV16/18 subtypes in 4. No expression of MDM2 protein and MDM2 mRNA was observed in normal skin. Our study indicated that the overexpression of MDM2 might be involved in malignant proliferation and carcinogenesis of CA.

Adolescent↗

PubMed2004

Unfolding kinetics of dimeric creatine kinase measured by stopped-flow small angle X-ray scattering.

The unfolding kinetics of creatine kinase (CK) in various concentrations of urea or guanidine hydrochloride (GuHCl) was investigated by small angle X-ray scattering (SAXS) using synchrotron radiation, and compared with the results obtained by stopped-flow circular dichroism and stopped-flow fluorescence. Using the three methods, the unfolding kinetics of CK fits well to a single exponential function with similar apparent rate constants, and the amplitude of the monophasic kinetics covers the entire range of the equilibrium values. The results suggest that the unfolding time-course measured by integrated SAXS intensity corresponds to the intramolecular loss of globular structure. The refolding kinetics of 8 M urea-denatured CK was monitored in a stopped-flow apparatus by following the spectroscopic changes, and the final state of folding was investigated by SAXS. A substantial part of the ellipticity is recovered within a burst phase, indicating that the secondary structure forms at an early stage in refolding. The R(g) value of the final folded state was 33.6 A when the folding buffer contained 20% glycerol, which is characteristic of native-like compactness and globularity.

Circular Dichroism↗

PubMed2004

Angiogenic signal triggered by ischemic stress induces myocardial repair in rat during chronic infarction.

In the present study, we examined a novel method of stimulating myocardial angiogenesis through ischemic preconditioning (IP) in the form of in vivo four repetitive cycles of coronary artery occlusion each followed by reperfusion. Rats divided into 4 groups: Control+Sham surgery (CS), Control+ Left anterior descending coronary artery (LAD) occlusion (CMI), IP+ Sham surgery (IPS) and IP+LAD occlusion (IPMI). For cardiac function, rats were subjected to stress testing with dobutamine after 2, 4, 7, 14 and 21 operative days. Capillary density (CD) and arteriolar density (AD) were evaluated by immunohistochemistry. Western blot was performed to examine the expression pattern for VEGF and anti-death candidates, Bcl-2 and survivin. Blood flow and the extent of endothelial and cardiomyocyte cell death were examined. The protein/DNA array was performed to determine the status of various transcription factor related to stress signal. Left ventricular functional reserve was better preserved in IPMI compared to the CMI group. The infarct size and apoptotic cell death were reduced in IPMI group significantly. Left ventricular regional blood flow, perfused capillary density and AD increased significantly in the IPMI group. VEGF, Bcl-2 and survivin expression were increased in IPMI compared to CMI. VEGF mediated vascular permeability was controlled in the IPMI due to suppression of c-Src in the infarcted myocardium. Our study documented first time the ability of IP to induce angiogenesis in the infarcted myocardium along with the activation of several transcription factors such as Stat3, Pax-5, NF kappa B, TFIID, SP1 and reduction of VEGF mediated vascular permeability by inhibition of c-Src in IPMI group thereby reducing ischemic injury in rat MI model.

Animals↗