Biomedical subjects
Publications and source records attributed to Wei He.
The first examples of a tandem Nazarov cyclization/Michael addition process are described. The sequence is efficiently catalyzed by Ir[Me(CO)(dppe)(DIB)]2+ and occurs with high diastereoselectivity, creating three contiguous stereocenters. The mechanistic factors controlling the reactivity and diastereoselectivity are discussed.
Nicotine reduces beta-amyloidosis and has a beneficial effect against Alzheimer's disease (AD), but the underlying mechanism is not clear. The abnormal interactions of beta-amyloid (Abeta) with metal ions such as copper and zinc are implicated in the process of Abeta deposition in AD brains. In the present study, we investigated the effect of nicotine on metal homeostasis in the hippocampus and cortex of APP(V717I) (London mutant form of APP) transgenic mice. A significant reduction in the metal contents of copper and zinc in senile plaques and neuropil is observed after nicotine treatment. The densities of copper and zinc distributions in a subfield of the hippocampus CA1 region are also reduced after nicotine treatment. We further studied the mechanism of nicotine-mediated effect on metal homeostasis by using SH-SY5Y cells overexpressing the Swedish mutant form of human APP (APPsw). Nicotine treatment decreases the intracellular copper concentration and attenuates Abeta-mediated neurotoxicity facilitated by the addition of copper, and these effects are independent of the activation of nicotinic acetylcholine-receptor. These data suggest that the effect of nicotine on reducing beta-amyloidosis is partly mediated by regulating metal homeostasis.
Using previously reported opioid receptor (OR) agonist analogs 4a-c as starting points, the structure-activity relationship (SAR) for their related series has been further refined. This SAR study has led to the identification of 2,6-di-Me-Tyr (DMT) analogs 4h and 4j as the most potent OR agonist within the series. In addition, it was discovered that 4-(aminocarbonyl)-2,6-dimethyl-Phe is a reasonable bioisostere surrogate for the DMT moiety, as supported by the OR activities of compounds 4x and 4y.
IFN regulatory factor-3 is a transcription factor that is required for the rapid induction of type I IFNs in the innate antiviral response. Two noncanonical IkappaB kinase (IKK) family members, IKKepsilon and TRAF family-associated NF-kappaB activator-binding kinase-1, have been shown to phosphorylate IFN regulatory factor-3 and are critically involved in virus-triggered and TLR3-mediated signaling leading to induction of type I IFNs. In yeast two-hybrid screens for potential IKKepsilon-interacting proteins, we identified Ret finger protein (RFP) as an IKKepsilon-interacting protein. Coimmunoprecipitation experiments indicated that RFP interacted with IKKepsilon and TRAF family-associated NF-kappaB activator-binding kinase-1 as well as the two canonical IKK family members, IKKbeta and IKKalpha. RFP inhibited activation of the IFN-stimulated response element and/or NF-kappaB mediated by the IKK family members and triggered by TNF, IL-1, polyinosinic-polycytidylic acid (ligand for TLR3), and viral infection. Moreover, knockdown of RFP expression by RNA interference-enhanced activation of IFN-stimulated response element and/or NF-kappaB triggered by polyinosinic-polycytidylic acid, TNF, and IL-1. Taken together, our findings suggest that RFP negatively regulates signaling involved in the antiviral response and inflammation by targeting the IKKs.
OBJECTIVE: To study the methods and points for attention of latissimus dorsi muscle flap transplantation to correct the thoracic malformation of Poland's syndrome. METHODS: From 1995 to 2003, 10 patients were diagnosed of Poland's syndrome with absence of pectoris major muscle in all patients. The latissimus dorsi muscle flap was exposed and transferred through a vertical lateral thoracic cut and a short cut beneath the axillary fold. Reconstruction of the anterior axillary wall is one of the major goals to be achieved in this operation. RESULTS: All of the latissimus dorsi muscle flaps survived. Satisfactory outcomes were achieved after 1-2 years of follow-up. CONCLUSION: The latissimus dorsi muscle flap has a stable and reliable blood supply. It is an ideal muscle flap to restore the thoracic malformation of Poland's syndrome.
The natural extracellular matrix (ECM) is a complex structure that is built to meet the specific requirements of the tissue and organ. Primarily consisting of nanometer diameter fibrils, ECM may contain other vital substances such as proteoglycans, glycosaminoglycan and various minerals. Current research in tissue engineering involves trying to replicate the ECM such that it provides the environment for tissue regeneration. Electrospinning is a versatile process that results in nanofibers by applying a high voltage to electrically charge a liquid. A variety of polymers and other substances have been incorporated into the artificial nanofibrous scaffold. Surface modification and cross-linking of the nanofibers are some ways to improve the biocompatibility and stability of the scaffold. Electrospun scaffolds with oriented nanofibers and other assemblies can be constructed by modifying the electrospinning setup. Using electrospinning, researchers are able to specifically tailor the electrospun scaffold to meet the requirements of the tissue that they seek to regenerate. In vitro and in vivo experiments demonstrate that electrospun scaffolds hold great potential for tissue engineering applications.
OBJECTIVE: To investigate the neuro-protective effect of Xuesaitong Injection (XST) on brain inflammatory response after transient focal cerebral ischemia/reperfusion in rats. METHODS: Focal cerebral ischemia/reperfusion models of male rats were induced by transient occlusion for 2 h of middle cerebral artery (MCA) which was followed by 24 h reperfusion. XST was administered through intraperitoneal injection of 25 mg/kg or 50 mg/kg at 4 h after the onset of ischemia. After reperfusion for 24 h, the neurological function score was evaluated, the brain edema was detected with dry-wet weight method, the myeloperoxidase (MPO) activity and the expression of intercellular adhesion molecule-1 (ICAM-1) of ischemic cerebral cortex and caudate putamen was determined by spectrophotometry and immunohistochemistry respectively. RESULTS: XST not only lowered neurological function score at the dose of 50 mg/kg, but reduced brain edema and inhibited MPO activity and ICAM-1 expression as compared with the ischemia/reperfusion model group (P < 0.01). CONCLUSION: XST has a definite effect on inhibiting the expression of ICAM-1 and neutrophil infiltration in rats with cerebral ischemia/reperfusion when treatment started at 4 h after ischemia onset, and also attenuates inflammation in the infarcted cerebral area.
To assess whether Smad signaling affects skin development, we generated transgenic mice in which a Smad antagonist, Smad7, was induced in keratinocytes, including epidermal stem cells. Smad7 transgene induction perturbed hair follicle morphogenesis and differentiation, but accelerated sebaceous gland morphogenesis. Further analysis revealed that independent of its role in anti-Smad signaling, Smad7 bound beta-catenin and induced beta-catenin degradation by recruiting an E3 ligase, Smurf2, to the Smad7/beta-catenin complex. Consequently, Wnt/beta-catenin signaling was suppressed in Smad7 transgenic hair follicles. Coexpression of the Smurf2 and Smad7 transgenes exacerbated Smad7-induced abnormalities in hair follicles and sebaceous glands. Conversely, when endogenous Smad7 was knocked down, keratinocytes exhibited increased beta-catenin protein and enhanced Wnt signaling. Our data reveal a mechanism for Smad7 in antagonizing Wnt/beta-catenin signaling, thereby shifting the skin differentiation program from forming hair follicles to sebaceous glands.
PURPOSE: To study the prognostic factors of squamous cell carcinoma of the buccal mucosa (BMSCC) with negative surgical margins. PATIENTS AND METHODS: Forty-five untreated negative marginal cases were studied for predictors of recurrence, cervical lymph node metastasis, and survival. Clinicopathologic features included age, gender, duration of tumor, primary tumor (T) classification, pathologic clinical stage, tumor differentiation, tumor thickness, number of mitoses, and lymphocytic infiltration. RESULTS: The recurrence and metastasis rate was 40% and 44.4%, respectively. With univariate analysis, the predictors of recurrence were T classification, tumor differentiation, pathologic clinical stage, and lymphocytic infiltration. Average tumor thickness was greater than 5.68 mm. For cervical lymph node metastasis, the predictors include T classification, tumor differentiation, and lymphocytic infiltration. Tumor thickness was greater than 5.17 mm; number of mitoses was greater than 2.92/high power field (HPF). With logistical regression, only tumor thickness was the predictor of recurrence. T classification and tumor thickness were the predictors for cervical lymph node metastasis. Using Cox multivariate proportional hazards regression model, the survival disadvantage factors were T classification and recurrence. The hazard grand for T classification was 2.185; for recurrence it was 74.808. CONCLUSIONS: Because T classification (between T1+T2 and T3+T4) and tumor thickness (more than 5.17 mm) were the predictors for cervical lymph node metastasis, neck dissection should be carried out routinely in T3 and T4 patients; whereas for T1 and T2 patients, neck dissection is necessary if tumor thickness is greater than 5.17 mm. T classification and recurrence are predictive factors for survival.
Phosgene inhalation can induced pulmonary edema formation. The purpose of this study was to investigate cell of apoptosis in pulmonary edema mice induced by phosgene. Fifty-two BALB/c mice were random divided into a negative group and a positive group with 26 mice in each. Mice were exposed for 5 min to air and phosgene in the negative group and in the positive one, respectively. The dose of phosgene was 539 ppm. After 4 h of exposure, all mice were anesthetized. Lungs were analyzed for lung wet/dry weight ratio and pathological alternation. The method of isolation and culture of alveolar type II cells (ATII cells) was established to observe their apoptosis by electron microscope and flow cytometry. Apoptosis of lung cells was observed by DNA gel electrophoresis and TUNEL. The lung wet/dry weight ratio was significantly higher in the positive group (6.42 +/- 1.00) than in the negative group (4.25 +/- 0.47, p < 0.05). A large amount of fluid effusion was observed in the alveolus of mice induced by phosgene. Alveolar type II cells were identified by tannic acid staining and electron microscope. The apoptotic signs in alveolar type II cells, alveolar type I cells, eosinophils, macrophages, symphocytes, and ciliated cells were viewed under electron microscope in positive group. The ratio of apoptosis cells (40.26 +/- 7.74) in positive was higher than that (1.58 +/- 1.01, p < 0.001) in the negative group by flow cytometry. DNA ladder alternation was seen through DNA gel electrophoresis. Apoptosis of epithelia and vascular endothelia in lung were found by TUNEL. These results indicate that there is success in establishing a model of pulmonary edema and method of isolation and culture of AT II cells in BALB/c mice. Phosgene can induce apoptosis of cells in the lungs of BALB/c mice, and this indicates that pulmonary edema is related to apoptosis of lung cells in mice, induced by phosgene.
It is well known that ozone (O3), a potent reactive oxidant and air pollutant, induces respiratory inflammation and hyperresponsiveness upon inhalation. It was previously shown that O3 exposure (0.6 ppm, 10 h/day for 15 days) not only results in local bronchial inflammation, but also affects the nervous system and thymocyte proliferation, and places mice under oxidative stress. In the present study, data showed that O3 exposure could impair both the natural killer (NK) cell activity and the proliferation potential of spleen T cells to a specific antigen stimulus. Immunological function assays indicated that O3 exposure attenuated the proliferation of spleen mononuclear cells induced by concanavalin A and decreased CD4+ and CD28+ lymphocyte subsets. However, supplementation with natural antioxidants protected mice from O3-induced dysfunction of splenocyte proliferation. Meanwhile, O3 exposure resulted in a decline of mitogen-induced IL-2 production in splenocytes. It was also found that O3 exposure dramatically enhanced the proliferation of CD4-CD8- thymocytes stimulated by recombinant mouse interleukin-7 (rmIL-7), which is usually observed during the mammal aging process. Taken together, data conclude that short-term repetitive O3 exposure damages both innate and acquired immunity via altering the lymphocyte subset and cytokine profile, and via impact on thymocyte early development. O3-induced oxidative damage is one of the key factors leading to immune dysfunction in this mouse model.
Ag85A and ESAT-6 proteins of Mycobacterium tuberculosis (M.TB) are important protective antigens. The 32-kDa Ag85A is a strong immunogen in both small and large animals. However, the 6-kDa ESAT-6 has relatively low inherent immunogenicity, especially in large animals. To improve the immunogenicity of ESAT-6 in animals, we made chimeric DNA vaccines, HG856K and HG856A, by inserting the esat-6 gene into the Kpn I or Acc I endonuclease restriction site of the ag85a gene, respectively. BALB/c mice were injected intramuscularly three times with the 10-microg singular DNA vaccine (HG85 encoding for Ag85A or HG6 encoding for ESAT-6) or chimeric DNA vaccine (HG856K or HG856A) followed by electroporation (EP). Ten days after the last DNA vaccination, mice received a booster immunization intraperitoneally with 50-microg pure recombinant protein Ag85A or ESAT-6 without adjuvant. Additional groups of mice immunized with chimeric DNA vaccines were boosted with two mixed proteins (Ag85A/ESAT-6) at the same time. The results showed that the immunogenicity of M.TB ESAT-6 antigen was not improved by priming with the HG6 DNA vaccine. However, the humoral immunity against the ESAT-6 antigen was significantly increased in the mice primed with chimeric DNA vaccines, HG856K or HG856A, followed by boosting with ESAT-6 or ESAT-6/Ag85A mixed proteins.
Maintaining functions of endothelial cells in vitro is a prerequisite for effective endothelialization of biomaterials as an approach to prevent intimal hyperplasia of small-diameter vascular grafts. The aim of this study was to design suitable nanofiber meshes (NFMs) that further maintain the phenotype and functions of human coronary artery endothelial cells (HCAECs). Collagen-coated random and aligned poly(L-lactic acid)-co-poly(epsilon-caprolactone) (P(LLA-CL)) NFMs were fabricated using electrospinning. Mechanical testing showed that tensile modulus and strength were greater for the aligned P(LLA-CL) NFM than for the random NFM. Spatial distribution of the collagen in the NFMs was visualized by labeling with fluorescent dye. HCAECs grew along the direction of nanofiber alignment and showed elongated morphology that simulated endothelial cells in vivo under blood flow. Both random and aligned P(LLA-CL) NFMs preserved phenotype (expression of platelet endothelial cell adhesion molecule-1, fibronectin, and collagen type IV in protein level) and functions (complementary DNA microarray analysis of 112 genes relevant to endothelial cell functions) of HCAECs. The P(LLA-CL) NFMs are potential materials for tissue-engineered vascular grafts that may enable effective endothelialization.
OBJECTIVE: To explore the primary regularity of cerebral electrical impedance (CEI) change in healthy people, patients with intracerebral hemorrhage (ICH) and patients with cerebral infarction (CI). METHODS: CEI of 200 healthy volunteers, 78 patients with ICH and 51 patients with CI were measured by noninvasive brain-edema monitor. The results of perturbative index (PI) converted from CEI were compared with the volumes of infarction, hematoma and surrounding edema, which were calculated by image analysing system according to MRI or CT scan. RESULTS: (1) In the normal groups, PI in the left and right sides of cerebral hemispheres was respectively 7.98 +/- 0.95 and 8.02 +/- 0.71, and there was no significant difference between the two sides (p>0.05). (2) In the patients with ICH, PI of the hematoma side initially was lower than the other side, but then increased and finally exceeded that of the other side. The average transitional time was 19.67 +/- 11.52 hours. Perturbative index of the hematoma side after the transitional time was much higher than before the transitional time in the same patients (7.79 +/- 0.75 versus 7.09 +/- 0.72) (p<0.001). The volumes of peri-hematoma edema were also significantly larger after the transitional time than before (24.32 +/- 12.86 versus 13.33 +/- 6.12) (p<0.05). There was a positive correlation between the PI of hematoma side and the volumes of peri-hematoma edema (p<0.01). (3) In the patients with arterothrombotic cerebral infarction, PI in the infarct side was higher than that in the opposite side 3-5 days after onset (8.93 +/- 1.89 versus 8.58 +/- 1.61) (p<0.001), and PI of the infarct side had a positive correlation with the volume of infarction (p<0.001). (4) The sensitivity of PI was high when the volumes of lesions were >20 ml or the position of them were located in the basal ganglia, but was low when the volumes were <20 ml or the position near the midline. CONCLUSION: CEI may be a useful parameter for noninvasively monitoring the change of brain edema and hematoma in stroke at bedside. It could be a good complement to CT and MRI.
OBJECTIVE: To investigate the cleavage activities of 10-23 DNA enzymes targeting at HBV C gene mRNA in vitro. METHODS: 10-23 DNA enzymes named DrzBC-7, DrzBC-8 and DrzBC-9 specific to HBV C gene ORF A1816UG were designed and synthesized. HBV C gene mRNA was obtained by in vitro transcription method. Cleavage activities were observed in vitro. The influence of MgCl2 concentration on RNA cleaving activity was examined with DrzBC-9. Values of kinetic parameters including Km, Kcat and Kcat/Km were calculated accordingly. RESULT: Targeted substrate mRNA with the size of 300 nt was obtained by transcription in vitro. Under the certain cleavage conditions, DrzBC-7, DrzBC-8 and DrzBC-9 all efficiently cleaved target mRNA at specific sites in vitro. Cleavage products of 109 nt and 191 nt were obtained. No cleavage occurred without MgCl2. The most efficient cleavage was obtained at 150 mmol x L(-1) MgCl2. The efficiency of cleavage did not increase when the MgCl2 concentration was more than 200 mmol x L(-1). The kinetic parameters, Km, Kcat and Kcat/Km for DrzBC-9 were 1.4x10(-9) mol x L(-1), 1.6 min(-1) and 1.1x10(9) mol x L(-1) x min(-1), respectively. CONCLUSION: 10-23 DNA enzymes targeting at HBV C gene mRNA possess the specific cleavage activities in vitro.
OBJECTIVE: To investigate the immune response of the fusions of ovarian carcinoma cells to dendritic cell (DC) transfected with interleukin (IL)-12 gene in vitro. METHODS: Recombinant human granulocyte macrophage colony stimulating factor and recombinant human tumor necrosis factor alpha were used to generate DC from cord blood in vitro. IL-12 fusion gene was cloned into a eukaryotic vector-pcDNA3.1 (+). DC were transfected with IL-12-pcDNA3.1 (+) using lipofectamine transfection method and electric transfection method respectively. Then polyethylene glycol mediated the fusion of transfected DC and ovarian carcinoma cells, and 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyl tetrazolium bromide (MTT) test was carried out to observe the immune response. RESULTS: DC were generated in vitro from cord blood and expressed high levels of costimulatory (50%) and MHC II molecules (99%). RT-PCR showed that IL-12-pcDNA3.1 (+) had been successfully transfected into DC. RT-PCR and immunofluorescence analysis showed that DC were fused with ovarian carcinoma cells successfully. Then the fusion cells of ovarian carcinoma cells to transfected DC, and the fusions of ovarian carcinoma cells to DC were cocultured with peripheral blood mononuclear cell respectively. MTT test showed that both fusions could induce cytolytic T cell activity and lysis of ovarian carcinoma cells, and the former effect was stronger. CONCLUSION: The cytolytic T cell activity induced by the fusions of ovarian carcinoma cells to transfected DC is enhanced.
OBJECTIVE: To investigate the protective effect of Sini decoction (SND) on intestinal mucosa in rats with intestinal ischemia reperfusion (I/R) and the mechanism relating to oxygen radical and Bcl-2 protein expression. METHOD: Thirty-two SD rats of both sexes were randomly divided into 4 equal groups: (1) control group in which sham operation was performed; (2) model group in which intestinal I/R was produced by clamping super mesenteric artery(SMA) for 1 hour and declamping SMA for 3 hours; (3) SND low dose group in which SND(3 g x kg(-1) x d(-1)) was given via stomach tube for 3 days before operation; (4) SND high dose group in which SND(6 g x kg(-1) x d(1)) was given via stomach tube, for 3 days before operation. A strip of small intestine was taken from distal end of ileum for light microscopic examination, Chiu's score and the detection of intestinal water content (IWC). Apoptosis of intestinal mucosa cell was examined by TUNEL method. Superoxide dismutase (SOD) activity, malondisldehyde (MDA) concentration of intestinal mucosa were detected. The protein express of Bcl-2 of intestinal mucosa was analyzed by immunochemistory. RESULT: Intestinal /R resulted in histopathological changes in intestinal mucosa, increased Chiu's scores, apoptosis index, IWC and MDA content, and reduced SOD activity and the protein expression of Bcl-2 significantly (P < 0.01). The pretreatment of SND could attenuate the above changes significantly (P < 0.01), but there was no significant difference for the above variables between SND low dose group and SND high dose group (P > 0.05). Apoptosis index was significantly negatively correlative to SOD activity in model group and two SND groups. There were significantly negative correlation between apoptosis index and protein expression of Bcl-2 in model group and SND low dose group. CONCLUSION: SND can attenuate intestinal mucosa injury following intestinal U/R, which is related to reducing intestinal mucosa cell apoptosis by removing oxygen free radical and upregulating the protein expression of Bcl-2.
OBJECTIVE: To observe clinical therapeutic effect of needle-sticking method on rheumatoid arthritis (RA) of wind-cold-damp retention type. METHODS: Fifty cases of such disease were divided into 2 groups in order of visiting. The treatment group (n = 30) were treated with needle-sticking method, and the control group (n = 20) with routine filiform needle therapy for 2 therapeutic courses. Total cumulative scores, numbers of both the pressure-pain joint and the swollen-distention joint, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), C reaction protein (CRP) before and after treatment were investigated. RESULTS: Both the needle-sticking method and the filiform needle therapy had an apparent therapeutic effect on RA of wind-cold-damp retention type, and the therapeutic effect for the clinical indexes in the treatment group was better than the control group, with a very significant difference in improvement of RF, the number of pressure-pain joints and the total cumulative scores as the treatment group compared with the control group (P < 0.01). CONCLUSION: Needle-sticking method has definite therapeutic effect on RA of wind-cold-damp retention type with obvious superiority.