Biomedical subjects

Di Wu

Publications and source records attributed to Di Wu.

At least 91 records · Page 5Linked to original sources

PubMed2005

Theoretical investigation of the large nonlinear optical properties of (HCN)n clusters with Li atom.

Two new classes of (HCN)(n)...Li and Li...(HCN)(n) (n = 1, 2, 3) clusters with the electride characteristic are formed in theory by the metal Li atom attaching to the (HCN)(n) (n = 1, 2, 3) clusters. Because of the interaction between the Li atom and the (HCN)(n) part, the 2s valence electron of the Li atom becomes a loosely bound excess electron. Our high-level ab initio calculations show that these new clusters with the excess electron have large first hyperpolarizabilities, for example, beta(0) = -15,258 au for (HCN)...Li and beta(0) = -3401 au for Li...(HCN) at the QCISD/6-311++G(3df,3pd) level (only beta(0) = -2.8 au for HCN monomer(26)). Obviously, the excess electron from the Li atom plays a crucial role in the large first hyperpolarizabilities of these clusters. The beta(0) value of (HCN)(n)...Li (beta(0) > 10(4) au, from sigma --> pi* transition) is larger than that of Li...(HCN)(n) (beta(0) > 10(3) au, from sigma --> sigma* transition) for n = 1, 2, or 3. In addition, two interesting rules have been observed. They are that |beta(0)| decreases with lengthening of the HCN chain for (HCN)(n)...Li clusters and that |beta(0)| increases as n increases for Li...(HCN)(n) clusters. In this paper, we discuss two classes of clusters that are highly similar to the electride structure model, of which the structural characteristics are that alkali metal atoms ionize to form cations and trapped electrons under the action of other polar molecules. Thus, the investigation on the large first hyperpolarizabilities of (HCN)(n)...Li and Li...(HCN)(n) (n = 1, 2, 3) may prompt one to study the unusual nonlinear optical responses of some electrides.

Journal Article↗

PubMed2005

Purification and characterisation of phenoloxidase from amphioxus Branchiostoma belcheri tsingtauense.

Phenoloxidase (PO) from the humoral fluid of amphioxus B. belcheri tsingtauense was purified using a sequential combination of ammonium sulphate precipitation, Sephadex G-200 chromatography and DEAE Sepharose Fast Flow chromatography. In PAGE, the purified enzyme exhibited a single band of 150 kDa under non-reducing conditions, and was resolved to three bands with molecular masses of 72, 46 and 44 kDa, respectively, under reducing conditions, suggesting that the PO in amphioxus humoral fluid seems to be a heterotrimer of three polypeptides held together by disulphide bonds. The substrate specificity and inhibition characteristics both indicate that the PO isolated from amphioxus humoral fluid is a tyrosinase-type enzyme. In addition, mouse antisera against the purified PO were prepared, and their specificity was confirmed by Western blotting, facilitating the future determination of the origin of PO in the humoral fluid and the distribution of PO-synthesising tissues in amphioxus.

Ammonium Sulfate↗

PubMed2005

No evidence for tumorigenesis of AAV vectors in a large-scale study in mice.

Six hundred ninety-five mice received adeno-associated virus (AAV) vectors, mostly via portal vein injection. At necropsy, the livers were inspected for tumors, and tissue sections were prepared for histology. We observed only one tumor, a lipoma, resulting in a tumor frequency of 0.14%. This tumor contained fewer vector genomes per total DNA than the surrounding liver tissue, as shown by quantitative PCR. In another mouse we found a macroscopically visible nodule containing lymphocytes. Immunohistochemistry revealed cells not of monoclonal origin, and they contained fewer AAV genomes than the surrounding hepatocytes. There were no macroscopic tumors in 226 control mice. Upon microscopic examination, lymphocytic infiltrates were found in 5% of livers of both control and vector-treated mice; no transgene expression was seen in those infiltrates in AAV-injected animals. Compared to an average frequency of spontaneous liver tumors in C57BL/6 mice (0-10%), and given the absence of high levels of vector DNA in the observed tumor, we conclude that AAV vectors do not predispose these target animals to the formation of liver tumors.

Animals↗

PubMed2005

Visible study of mercuric ion and its conjugate in living cells of mammals and plants.

The investigation of mercuric ion and mercuric conjugate inside live specimens has drawn intense attention because of their cytotoxicity. The translocation, transportation, and distribution of Hg2+ inside either mammals or plants, however, are still invisible due to the lack of favorable fluorescent molecular sensors for Hg2+. Here, two sensors, 2,6-bis(4'-peperazino-N'-hydroxylethoxylethylene-1',8'-naphthalimide)dimethylpyridine and 2,6-bis(4'-peperazino-N'-butyl-1',8'-naphthalimide)dimethylpyridine, which were composed of nitrogen atoms of 2,6-bis(aminomethyl)pyridine as the ion receptor and the donor of photoinduced electron transfer, were applied to the cultured mammalian cells and plant cells. Their membrane permeability, low toxicity, slow bleaching/fading, and high selectivity and sensitivity to Hg2+ in a live cell rendered them attractive to become real-time and real-space sensors. For the first time, the transportation of Hg2+ cation and Hg2+ conjugate of cysteine was observed with the help of a fluorescence microscope. The chloroplast location of Hg2+ in transgenic tobacco was also visible.

Animals↗

PubMed2005

Associations of baseline blood pressure levels and efficacy of Benazepril treatment with interaction of alpha-adducin and ACE gene polymorphisms in hypertensives.

The molecular mechanisms underlying essential hypertension are not fully elucidated. Although Benazepril is being widely used in antihypertensive medication, the agent is efficacious in only a portion of hypertensive patients. To evaluate the interaction of alpha-adducin gene Gly460Trp and angiotensin I-converting enzyme (ACE) gene I/D polymorphisms in regard to baseline blood pressure (BP) levels and the reductions of blood pressures after Benazepril treatment, we conducted an investigation of 954 Chinese hypertensive patients in Anhui province, China. We found that compared with the baseline systolic BP (SBP) of subjects with one ACE I allele and one alpha-adducin Trp allele, the baseline SBP of those with ACE DD and alpha-adducin Gly/Gly genotypes was significantly higher [Crude: beta(SE) = 7.83(3.09), p = .01; Adjusted: beta(SE) = 5.83(2.83), p = .04]. However, no associations were found between the interaction of ACE I/D and alpha-adducin Gly460Trp polymorphisms and the baseline diastolic BP or the BP response to Benazepril treatment. Our results suggested that the interaction effect of alpha-adducin Gly460Trp and ACE I/D polymorphisms might play a significant role in regulating baseline BP but not BP response to Benazepril.

Adult↗

PubMed2005

NANOG changes in mouse kidneys with age.

NANOG is essential for mouse and human embryonic stem cell (ESC) pluripotency and selfrenewal. It is also expressed in several adult murine tissues as shown by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. However, human NANOG transcripts have been isolated from adult bone marrow (EST; GenBank accession no. BF893620). Here, we study the NANOG gene expression profile in isolated mouse renal papillary cells by Northern blot and RT-PCR. The whole RNA of mouse renal cells was obtained from fresh renal tissues, renal tissues infused by phosphate-buffered saline (PBS), and isolated renal papillary cells of mouse, respectively, as well as the renal papillary tissue from 18.5 days postcoitum (d.p.c.; fetal), 1-2-week-old (young), 1-8-month-old (adult), and 24-month-old (aging) mice. Our analysis shows that a very low expression level was detected in mouse renal tissues, and the renal papillary cells express more than other tissues as determined with Northern blot and RT-PCR. These data suggest that the kidney has its own cells expressing NANOG, and loss of NANOG expression occurs in an age-dependent manner in the kidney, either due to developmental factors or aging, particularly in renal papillary tissue.

Aging↗

PubMed2005

Mitochondrial pathway is responsible for aging-related increase of tubular cell apoptosis in renal ischemia/reperfusion injury.

Aging-related changes of tubular cell apoptosis and its mechanisms in renal ischemia/reperfusion (I/R) injury are unclear. In the present study, aged (27-month-old) and young (3-month-old) Wistar rats were used to investigate aging-related tubular cell apoptosis in the setting of renal I/R injury. The renal I/R model was induced by clamping bilateral renal arteries for 30 minutes followed by reperfusion for 18 hours. Cyclosporine A (CsA, 2 mg/kg) or mycophenolate mofetil (MMF, 20 mg/kg/d) was used before ischemia. Age-matched sham-operated rats served as controls. We found that tubular cell apoptosis increased more significantly in aged rats than in young rats after renal I/R. More pronounced increases of Bax/Bcl-2 ratio, cytosolic cytochrome c, and caspase-9, which are involved in mitochondria-mediated apoptosis, were found in aged rats than in young rats, and were associated with a more pronounced decrease in superoxide dismutase activity and increase of malondialdehyde content. However, increases of tumor necrosis factor-alpha and caspase-8, two components of death receptor-mediated apoptosis, showed no aging-related differences. Interfering mitochondria and death receptor pathways with CsA and MMF, respectively, reduced the apoptosis in both age groups, whereas CsA was more effective in aged rats. Our results have demonstrated that there was an aging-related increase of tubular cell apoptosis in the renal I/R model, which may be, at least partly, due to an enhanced mitochondrial pathway resulting possibly from increased oxidative stress.

Aging↗

PubMed2005

Different expression of macrophages and microglia in rat spinal cord contusion injury model at morphological and regional levels.

Macrophages and microglia are implicated in spinal cord injury, but their precise role is not clear. In the present study, activation of these cells was examined in a spinal cord injury model using 2 different antibodies against ED1 clone and ionized calcium binding adaptor molecule 1 (Iba1). Activation was observed at 1, 4, 8, and 12 weeks after contusion injury and was compared with sham operated controls. Our results indicate that activation could be observed in both the dorsal funiculus and the ventral white matter area in the spinal cord at 5 mm rostral to the epicenter of injury. For both cells, there was a gradual increase in activation from 1-4 weeks, followed by down-regulation for up to 12 weeks. As a result, we could stain macrophages by ED1 and microglia by Iba1. We concluded that macrophages may play a role in the phagocytosis of denatured dendrites after spinal cord injury, while microglia may have some cooperative functions, as they were found scattered near the macrophages.

Animals↗

PubMed2005

[Clinical trial and evaluation on comprehensive treatment on attack in acute stage: report of 522 cases].

OBJECTIVE: To investigate the clinical effect of the comprehensive treatment to acute stage of attack. METHODS: On the basis of the previous observation, the study of the randomization control with general treatment, treatment on acupuncture and western medical treatment were carried out. A comprehensive treatment on overall traditional Chinese medical differentiation according to the superiority of every treatment was assessed and evaluated in 522 patients with attack. RESULTS: The comprehensive treatment of cerebral infarction was superior to the western medicine treatment. General treatment, treatment on traditional Chinese medical differentiation, acupuncture group revealed different improvement on neural function, daily viability, cognitive function in various extent. CONCLUSION: The comprehensive treatment that based on overall traditional Chinese medical differentiation has advantage and characteristic. It has positive combined action to the attack and relevant to clinical setting, easier to popularization and application. Various appraising amount form has different evaluating effects in different stage.

Acupuncture Therapy↗

PubMed2005

[Cloning and sequence analysis of human uric acid transporter gene].

OBJECTIVE: To obtain full-length human urate transporter (hUAT) gene. METHODS: Primers was designed according to the sequence of hUAT reported in Genbank. The target fragments were obtained by reverse transcriptional (RT) PCR from the mRNA extracted from human renal tubular epithelial cell lines (HK-2), followed by cloning into pEGFP-C1 plasmid. The cloned fragment was subjected to restriction mapping and sequence analysis for confirmation. RESULTS AND CONCLUSION: hUAT gene with correct sequence is successfully cloned from HK-2 cells. The restriction maps and sequence analysis of the selected clones were consistent with the sequence reported in Genbank.

Base Sequence↗

PubMed2005

[The construction of pSecTag2/B vector modified by osteoprotegerin].

PURPOSE: In order to treat periodontitis by using tissue engineering and gene engineering technology, we constructed mammalian secreted expression pSecTag2/B-OPG vector, the cDNA sequence encoding osteoprotegerin(OPG) obtaining from 293 cell. METHODS: The primers were designed based on the human OPG cDNA sequence. Total mRNA was isolated from 293 cells and RT-PCR was performed .The fragment was recombined into pSecTag2/B vector and sequenced by automatic sequence analyzer. RESULTS: The sequences of OPG cDNA from 293 cell by RT-PCR were completely identical to the sequences provided by GenBank [gi:33878056]. After polymerase chain reaction and the recombinant plasmid digesting with Hind III,EcoR I and BamH I,1% agarose electrophoresis showed several fragments, which were consistent with predicted size. CONCLUSION: From cultured 293 cells the cDNA has been cloned and pSecTag2/B-OPG vector has been constructed successfully. Supported by Research Fund (No.03043304) from Anhui Provincial Natural Science Foundation.

Animals↗

PubMed2005

[A study on drug compliance in secondary prevention of ischemic stroke].

OBJECTIVE: The aim of the present study is to determine the rate of compliance with secondary stroke prevention one year after ischemic stroke and to identify the reasons for poor compliance. METHODS: The proportion of patients compliant with prevention of risk factors (hypertension, diabetes, hyperlipidemia) was evaluated through structured telephone interviews. RESULTS: Of the consecutive patients admitted to the neurological department of Tiantan Hospital between Oct. 2002 and Apr. 2003, 374 patients were involved in this investigation and 296 (79.1%) were finally evaluated. In the 296 (79.1%) patients, the rate of antithrombotic drug compliance was 35.1%. Of the patients with hypertension, diabetes, and hyperlipidemia, 77.9%, 80.2%, and 48.4% were still treated for their respective risk factors. Influence factors for drug compliance, such as medical insurance and free medical care (OR 2.117, 95% CI 1.174-3.821) can promote the drug compliance in stroke patients, while the use of antithrombotic drugs other than aspirin (OR 0.352, 95% CI 0.153-0.812) and a lower living ability (62.5 +/- 13.3) (Mann-Whitney-P = 0.000) could decrease the drug compliance. CONCLUSIONS: Long-term compliance with secondary prevention in patients with ischemic stroke is poor in the setting of our study. Poor compliance with antithrombotic therapy such as incorrect discontinuation or change and reduction of dosage was noted. Means of payment, income levels, categories of antithrombotic drugs and personal living ability of patients are associated with compliance. Doctors should attach importance to secondary prevention and provide stroke patients detailed guidelines for the use of preventive drugs.

Aged↗

PubMed2005

[Association between the beta 2 adrenergic receptor polymorphism and blood pressure in YueXi population].

OBJECTIVE: To investigate the association between Arg16Gly polymorphism of beta(2)-adrenergic receptor (ADRB2) gene and blood pressure levels. METHODS: A total of 487 hypertensive individuals were recruited from YueXi county of Anhui province. 672 patients' parents and siblings were also invited to take part in the study and used as genomic control. Blood pressure was measured and a standardized questionnaire regarding social-economic characteristics, general health status, occupational history and life-style and dietary factors was administered for each participant. The ADRB2 Arg16Gly polymorphism was genotyped by using a PCR-Restriction Fragment Length Polymorphism (RFLP) method. The association between the ADRB2 polymorphism and hypertension in hypertensive adults was determined by utilizing a family-based association test analysis. RESULTS: In this study population, carriers of the ADRB2 Arg16 allele had lower systolic (P < 0.01) and diastolic (P < 0.01) blood pressure, suggesting that the genetic effect on blood pressure was more likely to fit an additive model. CONCLUSION: Our results suggest a probable association between Arg16Gly polymorphism of ADRB2 gene and hypertension.

Adult↗

PubMed2005

[Clinical and experimental study of xiaoshui decoction in the treatment of primary liver cancer caused ascites].

OBJECTIVE: To observe the clinical efficacy of Xiaoshui Decoction (XSD) in treating ascites in patients suffered from primary liver cancer of Pi-deficiency with damp harassment syndrome (PDDHS) as well as to study the effect through the experiment in mice. METHODS: Sixty-one patients confirmed to be primary liver cancer of PDDHS and accompanied with ascites were randomly divided into the treated group (n=33) and the control group (n=28). The treated group was treated by XSD combined with chemotherapy by locally applying of DDP via abdominal infusion, while the control group treated by DDP infusion alone. The treatment lasted for two months. The conditions of ascites, quality of life (QOL), survival period, and TCM syndrome after treatment were observed. In the experimental study, the mice models of ascites were grouped and treated to observe the conditions of ascites and their survival period. RESULTS: The short-term total effective rate of the treated group and the control group was 42.4% and 21.4%, the interval of aspirating ascites after treatment was 17.95 +/- 9.63 days and 10.87 +/- 7.76 days, and the 1-year survival rate 33.3% and 14.3%, respectively, significant difference was shown between the two groups in the three parameters (all P < 0.05 ). QOL was improved in both groups with insignificant difference (P > 0.05). Besides, the main symptoms were improved in patients of both groups, especially in the ameliorating of fatigue, abdominal distension, nausea and vomiting. Evaluation on safety of treatment showed that XSD had no obvious toxic and adverse reaction, and so it was safe in use. Experimental study showed that on the two mice models of ascites induced by inoculating two kinds of tumor cell, the effect of XSD was superior to that of the control group in aspects of reducing ascites and prolonging survival period, showing significant difference (P < 0.05). CONCLUSION: Satisfactory short-term efficacy in treating primary liver cancer with ascites of the Pi-deficiency with damp harassment syndrome could be obtained by XSD. Its effect in prolonging survival period was confirmed by experimental study. XSD can also improve the symptoms and QOL of patients, therefore, it is an effective and reliable remedy for treatment of primary liver cancer with ascites.

Adult↗

PubMed2004

Fbxw7/Cdc4 is a p53-dependent, haploinsufficient tumour suppressor gene.

The FBXW7/hCDC4 gene encodes a ubiquitin ligase implicated in the control of chromosome stability. Here we identify the mouse Fbxw7 gene as a p53-dependent tumour suppressor gene by using a mammalian genetic screen for p53-dependent genes involved in tumorigenesis. Radiation-induced lymphomas from p53+/- mice, but not those from p53-/- mice, show frequent loss of heterozygosity and a 10% mutation rate of the Fbxw7 gene. Fbxw7+/- mice have greater susceptibility to radiation-induced tumorigenesis, but most tumours retain and express the wild-type allele, indicating that Fbxw7 is a haploinsufficient tumour suppressor gene. Loss of Fbxw7 alters the spectrum of tumours that develop in p53 deficient mice to include a range of tumours in epithelial tissues such as the lung, liver and ovary. Mouse embryo fibroblasts from Fbxw7-deficient mice, or wild-type mouse cells expressing Fbxw7 small interfering RNA, have higher levels of Aurora-A kinase, c-Jun and Notch4, but not of cyclin E. We propose that p53-dependent loss of Fbxw7 leads to genetic instability by mechanisms that might involve the activation of Aurora-A, providing a rationale for the early occurrence of these mutations in human cancers.

Animals↗

PubMed2004

Asymmetric bias in free-energy perturbation measurements using two Hamiltonian-based models.

We present two model systems that are suitable for the study of bias in free-energy perturbation (FEP) calculations which are performed in molecular simulations. The models exhibit the asymmetry that is sometimes seen in these calculations, in which the magnitude of the bias is greater when the calculation is performed in one direction ( A-->B , sampling system A and perturbing into system B ) versus the other (B-->A) . Both models are formulated as a system of N independent particles, each sampling a space in the presence of a one-body field that is different for the A and B systems. In one model the field is a harmonic potential. The other model is discrete, such that each particle can be at one of two points (or states) of different energy. The neglected-tail bias model is applied to each system to estimate the average bias as a function of the amount of FEP sampling, and numerical calculations are performed to show that the bias model is effective. We show that the bias is significantly smaller when sampling is performed on the system having a broader work distribution (we designate this direction "insertion") compared to the bias for FEP calculations that sample the system with a narrower distribution ("deletion").

Journal Article↗

PubMed2004

The static polarizability and first hyperpolarizability of the water trimer anion: ab initio study.

This work predicts the extraordinary hyperpolarizability of inorganic clusters: two water trimer anions. The first hyperpolarizabilities of (H2O-)(3) are considerable, beta(0)=1.715 x 10(7) a.u. for configuration A and beta(0)=1.129 x 10(7) a.u. for configuration B at MP2/d-aug-cc-pVDZ+x level. The first hyperpolarizabilities of (H2O-)(3) (configuration A) and related systems [(H2O)(3) and (H2O)(3)F-] are compared at the MP2/d-aug-cc-pVDZ+x level. These results are beta(0)=1.715 x 10(7) a.u. for (H2O-)(3), beta(0)=35 a.u. for (H2O)(3) [the neutral core of (H2O-)(3)], and beta(0)=46 a.u. for (H2O)(3)F-). Comparing the beta(0) values of related systems, we find that the dipole-bound excess electron is the key factor in the extraordinary first hyperpolarizability of (H2O-)(3) species. It will provide a future in the development of some materials with the excess electron (e.g., electrides) that exhibit large nonlinear optical response.

Journal Article↗

PubMed2004

Characteristic of structures and pi-hydrogen bond of dimers C2H4-nFn-HF (n=0,1,2).

By the counterpoise-correlated potential energy surface method (interaction energy optimization), five structures of the C(2)H(4-n)F(n)-HF (n = 0,1,2) dimers with all real frequencies have been obtained at MP2/aug-cc-pVDZ level. The influence of F substituent effect on the structure and pi-hydrogen bond of dimer has been discussed. For C(2)H(4-n)F(n)-HF (n = 1,2), the pi-hydrogen bonds are elongated comparing with that for C(2)H(4)-HF. For C(2)H(3)F-HF, g-C(2)H(2)F(2)-HF, cis-C(2)H(2)F(2)-HF, the pi-hydrogen bonds are further deformed. These changes (elongate, shift, and deformation) of pi-hydrogen bond mainly come from deformation of pi-electron cloud of C=C bond. The pi-electron cloud is pushed towards the one C atom, the pi H-bond shift also to the C direction. Since the two lobes of pi-electron cloud have deviated slightly from the molecular vertical plane passing through C=C bond, the pi-hydrogen bond is sloped. Intermolecular interaction energies of the dimers are calculated to be -3.9 for C(2)H(4)-HF, -2.8 for C(2)H(3)F-HF, -2.1 for g-C(2)H(2)F(2)-HF, -1.6 for cis-C(2)H(2)F(2)-HF, -1.3 kcal/mol for trans-C(2)H(2)F(2)-HF, at CCSD(T)/aug-cc-pVDZ level.

Journal Article↗