Biomedical subjects
Publications and source records attributed to F Wang.
A new glucoside, selaginoside (1), together with two known compounds, hinokiflavone (2) and 2,3-dihydroamentoflavone (3), were isolated from the whole plants of Selaginella sinensis. Their structures were elucidated by means of spectroscopic methods.
BACKGROUND: Mesenchymal stem cells (MSC) have the capacity to differentiate into cells of connective tissue lineages, including bone, fat, cartilage and muscle, but the differentiation of embryonic MSC into epidermal cells by mesenchymal-epithelial transition has not been confirmed. OBJECTIVES: To determine the biological characteristics of human embryonic MSC (hMSC) and their potential for differentiation into epithelial cells. METHODS: hMSC were derived from 4-7-week-old embryos; they were localized and isolated, then primary culture was done. The biological characteristics of hMSC were detected by immunohistochemical methods and flow cytometry. Their differentiation potential was determined by coculture with conditioning medium and in vivo injection. RESULTS: hMSC express the relative specific antigens of MSC, such as SH2, alpha-smooth actin, CD29, CD44, CD90 and S100. After stimulation and in vivo transplantation, hMSC possess the potential to differentiate into epidermal cells with the production of keratin 19 and E-cadherin. CONCLUSIONS: hMSC derived from the early human embryo have the ability to transform into epidermal cells in vivo and in vitro.
Thyroid hormones play critical roles in brain maturation and cognitive functions. The present study investigated the role of thyroid hormone in emotional learning and memory using trace and delay contextual and cued fear conditioning tasks, respectively. Rats were administered triiodothyronine (T3) into the dorsal hippocampal area 10 min before training or immediately after training, and were scored for freezing behaviour in the same context and in a novel context with and without an auditory cue that had been paired previously with an aversive stimulus, a foot shock. Rats administered T3 before and after training both exhibited significantly increased long-term fear memory in the trace cued and the delay contextual fear conditioning procedures compared to their control groups. The T3-administered rats were not significantly different from their respective controls on the acquisition and short-term fear memory in the trace and delay fear conditioning tasks. No significant difference on long-term trace contextual and delay cued fear memory, respectively, was found. These results indicate that the observed T3-induced enhancement of long-term contextual and cued fear memory was specific to the hippocampus-dependent conditioning tasks. These findings are the first to demonstrate that infusion of T3 into the dorsal hippocampus can improve performance on an emotional memory task.
Major histocompatibility complex (MHC) class I chain-related gene A (MICA) is located 46 kb centromeric to HLA-B and encodes a stress-inducible protein. MICA allelic variation is thought to be associated with disease susceptibility and immune response to transplants. This study was aimed to investigate the haplotypic diversity and linkage disequilibrium between human leukocyte antigen (HLA)-B and (GCT)(n) short tandem repeat in exon 5 of MICA gene (MICA-STR) in a southern Chinese Han population. Fifty-eight randomly selected nuclear families with 183 members including 85 unrelated parental samples were collected in Hunan province, southern China. HLA-B generic typing was performed by polymerase chain reaction-sequence-specific priming (PCR-SSP), and samples showing novel HLA-B-MICA-STR linkage were further typed for HLA-B allelic variation by high-resolution PCR-SSP. MICA-STR allelic variation and MICA gene deletion (MICA*Del) were detected by fluorescent PCR-size sequencing and PCR-SSP. Haplotype was determined through family segregation analysis. Statistical analysis was applied to the data of the 85 unrelated parental samples. Nineteen HLA-B specificities and seven MICA-STR allelic variants were observed in 85 unrelated parental samples, the most predominant of which were HLA-B*46, -B60, -B*13, and -B*15, and MICA*A5, MICA*A5.1 and MICA*A4, respectively. Genotype distributions of HLA-B, MICA-STR loci were consistent with Hardy-Weinberg proportions. The HLA-B-MICA-STR haplotypic phases of all 85 unrelated parental samples were unambiguously assigned, which contained 30 kinds of HLA-B, MICA-STR haplotypic combinations, nine of them have not been reported in the literature. Significant positive linkage disequilibria between certain HLA-B and MICA-STR alleles, including HLA-B*13 and MICA*A4, HLA-B*38 and MICA*A9, HLA-B*58 and MICA*A9, HLA-B*46 and MICA*A5, HLA-B*51 and MICA*A6, HLA-B*52 and MICA*A6, and HLA-B60 and MICA*A5.1, were observed. HLA-B*48 was linked to MICA*A5, MICA*A5.1 and MICA*Del. HLA-B*5801-MICA*A10 linkage was found in a family. Our data indicated a high degree of haplotypic diversity and strong linkage disequilibrium between MICA-STR and HLA-B in a southern Chinese Han population, the data will inform future studies on anthropology, donor-recipient HLA matching in clinical transplantation and HLA-linked disease association.
VEGF plays a key role in ovarian carcinoma. Recent studies have shown that expressions of VEGF and its receptors were correlated with signal tranducer phosphorylation and activators of transcription 3(p-STAT3) in ovarian carcinoma. The aim of this study was to investigate the effects of STAT3 phosphorylation on VEGF signaling pathways in ovarian carcinoma cells. We selected an ovarian carcinoma cell line Caov-3 as a target cell that co-expressed VEGFR2 and p-STAT3. We detected expressions of p-STAT3 in Caov-3 induced by VEGF with different concentrations and for different effect times by immunocytochemistry and Western Blot. A concentration of 50 ng/ml VEGF was enough to increase phosphorylation of STAT3, and at 30 min, the p-STAT3 level reached the peak and showed nuclear translocation of p-STAT3 from the cytoplasm to the nucleus. These effects could be overcome by a small peptide (ATWLPPR) specific for VEGFR2. Taken together, VEGF-induced phosphorylation and nuclear translocation of STAT3 and ATWLPPR could effectively block the VEGF effects, suggesting that phosphorylation of STAT3 participates in VEGF signal transduction via VEGFR2 in ovarian carcinoma cells.
OBJECTIVES: To investigate the pattern of telomerase activity and the subunit of telomerase in normal placentae and GTD, and to determine the prognostic significance of telomerase activity and the subunit of telomerase in GTD. METHODS: Telomerase activity human telomerase (hTERT) and human telomerase (hTR) expression were analyzed in the initial uterine evacuation specimen of 63 hydatidiform moles (HMs), 42 normal human placental tissues, 17 malignant gestational trophoblastic tumors, primary cultures of normal villi and JAR cell lines by use of the polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay and reverse transcription-polymerase chain reaction (RT-PCR) methods. RESULTS: Telomerase activity was 100% in primary cultures of normal villi and JAR cell lines and in less than 60-day early placental villi, while only 9.1% in greater than 60-day placental villi, 27% in HMs and 58% in malignant trophoblastic tumors. High levels of hTR could be found in all groups. hTR expression was detected in all cases of < 60-day placental villi, in 72.7% > 60-day placental villi, in 87.3% in HMs and 100% in malignant trophoblastic tumors. Telomerase activity and hTERT expression had significant differences among the groups. Telomerase activity was associated with serum hCG levels but not related to other clinical risk factors. CONCLUSIONS: Telomerase activity may be correlated with the development of trophoblastic tumors, and hTERT may be a useful diagnostic marker for detecting the existence of malignant trophoblastic cells.
Open reading frame 79 of Bombyx mori nucleopolyhedrovirus (Bm79) is a conserved gene whose homologues have been identified in all 26 of the completely sequenced baculovirus genomes, including lepidopteran NPVs and GVs, hymenopteran NPVs, and a dipteran baculovirus. Northern blot analysis showed that the Bm79 transcript was about 850 nucleotides long and was initiated 12 h p.i. Temporal expression analysis revealed a 28-kDa protein, which was detected beginning 24 h p.i. using a polyclonal antibody against GST-Bm79 fusion protein. The 28-kDa protein was detected in the occlusion-derived virus envelope (ODV-E), but not in budded viruses. This observation was confirmed by observing ultrathin sections of polyhedra using immunoelectron microscopy. This demonstrated that the protein was present within the nuclei of cells. These results suggest that Bm79 is a functional gene that encodes a structural protein associated with the envelope of occlusion-derived virus (ODV).
Results of a study of the valence electronic structure of norbornene (C(7)H(10)), up to binding energies of 30 eV, are reported. Experimental electron momentum spectroscopy (EMS) and theoretical Green's function and density functional theory approaches were utilized in this investigation. A stringent comparison between the electron momentum spectroscopy and theoretical orbital momentum distributions found that, among the tested models, the combination of the Becke-Perdew functional and a polarized valence basis set of triple-zeta quality provides the best representation of the electron momentum distributions for all 19 valence orbitals of norbornene. This experimentally validated model was then used to extract other molecular properties of norbornene (geometry, infrared spectrum). When these calculated properties are compared to corresponding results from independent measurements, reasonable agreement is typically found. Due to the improved energy resolution, EMS is now at a stage to very finely image the effective topology of molecular orbitals at varying distances from the molecular center, and the way the individual atomic components interact with each other, often in excellent agreement with theory. This will be demonstrated here. Green's Function calculations employing the third-order algebraic diagrammatic construction scheme indicate that the orbital picture of ionization breaks down at binding energies larger than about 22 eV. Despite this complication, they enable insights within 0.2 eV accuracy into the available ultraviolet emission and newly presented (e,2e) ionization spectra. Finally, limitations inherent to calculations of momentum distributions based on Kohn-Sham orbitals and employing the vertical depiction of ionization processes are emphasized, in a formal discussion of EMS cross sections employing Dyson orbitals.
An in vitro relative potency (IVRP) assay has been developed as an alternative to the mouse potency assay used to release Merck's human papillomavirus (HPV) vaccine, Gardasil, for early phase clinical trials. The mouse potency assay is a classical, in vivo assay, which requires 4-6 weeks to complete and exhibits variability on the order of 40% relative standard deviation (RSD). The IVRP assay is a sandwich-type immunoassay that is used to measure relative antigenicity of the vaccine product. The IVRP assay can be completed in three days, has a variability of approximately 10% RSD and does not require the sacrifice of live animals. Because antigen detection is achieved using H16.V5, a neutralizing monoclonal antibody, which binds to a clinically-relevant epitope, the relative antigenicity measured by the IVRP assay is believed to be a good predictor of in vivo potency. In this study, the relationship between immunogenicity, as measured by the mouse potency assay and antigenicity as measured by the IVRP assay, is demonstrated. Freshly manufactured and aged samples produced using two different manufacturing processes were tested using both methods. The results demonstrate that there is an inverse correlation between the IVRP and mouse potency assays. Additionally, clinical results indicate IVRP is predictive of human immunogenicity. Thus, antigenicity, as defined by the H16.V5 epitope, can be used as a surrogate for immunogenicity and the IVRP assay is suitable for use as the sole potency test for Gardasil samples.
AIMS/HYPOTHESIS: Islet amyloid polypeptide (IAPP) reduces food intake and body weight in laboratory animals. In addition, IAPP appears to regulate nutrient metabolism. In the present studies, we investigated the effect of chronic IAPP treatment on different aspects of energy homeostasis. METHODS: IAPP was infused (25 pmol/kg/min) from subcutaneous osmotic pumps for 2-7 days. Rats in 2 saline-infused control groups were fed ad libitum (AF) or pair-fed (PF) against the IAPP-treated rats. RESULTS: As expected, the IAPP infusion reduced food intake and body weight gain. In addition, the IAPP treatment decreased the epididymal fat pad (vs. PF rats, p < 0.05) and lowered circulating levels of triglycerides (vs. PF rats, p < 0.05), free fatty acids (vs. PF rats, p < 0.05), leptin (vs. both AF and PF rats, p < 0.05) and insulin (vs. AF rats, p < 0.05). In contrast, glucose and protein metabolism in the IAPP-treated rats was largely unchanged, as shown in results regarding serum glucose, glucose transport in skeletal muscle, blood urea nitrogen, and glycogen and protein content in the liver and in skeletal muscle. CONCLUSION/INTERPRETATION: In summary, chronic IAPP exposure led to a changed lipid metabolism, which was characterized by decreased adiposity, hypolipidemia and hypoleptinemia, and to unchanged glucose and protein homeostasis. These results were similar to those seen in rodents during chronic exposure to another satiety/adiposity regulator, leptin. In conclusion, chronically administered IAPP plays a role as a satiety and adiposity signal in rats, and helps regulate energy homeostasis.
We report a study of spin waves in ferromagnetic La1-xCaxMnO3, at concentrations x=0.17 and x=0.2 very close to the metallic transition (x=0.225). Below T(C), in the quasimetallic state (T=150 K), nearly q-independent energy levels are observed. They are characteristic of standing spin waves confined into finite-size ferromagnetic domains, defined only in the (a,b) plane for x=0.17, and in all directions for x=0.2. They allow an estimation of the domain's size, a few lattice spacings, and of the magnetic coupling constants inside the domains. These constants, anisotropic, are typical of an orbital-ordered state, allowing one to characterize the domains as "hole poor." The precursor state of the collossal magnetoresistance metallic phase appears, therefore, as an assembly of small orbital-ordered domains.
Explore the source record for details and available documents.
INTRODUCTION: The value of synchronous liver resection and cryotherapy ablation remains controversial for colorectal metastases where complete resection is not possible by conventional liver surgery alone. OBJECTIVE: To review the long-term survival of patients treated using this approach at our institution. METHODS: A review was undertaken of data held in the prospectively collected liver surgery database of all patients who underwent synchronous liver resection and cryotherapy. Survival analysis was performed and data recorded on the total number of metastases at initial surgery and the number of lesions treated by cryoablation. RESULTS: Ninety-three patients with colorectal metastases underwent synchronous liver resection and cryotherapy. Data were available on 86 patients with a median follow-up of 18 months (range 1-83). The median number of metastases at initial surgery was four (range 2-11) and the number of lesions treated by cryotherapy ablation was two (range 1-8). Eighty-four per cent had a hepatic artery catheter inserted at surgery and at least one cycle of post-operative hepatic artery chemotherapy. One-, three- and five-year survival was 85%, 43% and 19% respectively, with a median survival of 33 months (95% confidence interval 19.9-42.1). Site of recurrence was recorded and presented. CONCLUSIONS: Patients with liver metastases that are not amenable to resection alone can achieve worthwhile median survival with synchronous liver resection and cryotherapy ablation.
Human leukocyte antigen (HLA) class I allelic genotypes were determined in 105 unrelated Han ethnic individuals inhabiting the northern China area. A total of 19 HLA-A alleles, 49 HLA-B alleles and 24 HLA-Cw alleles were detected. Through the analyses of two and three loci haplotypes of HLA-A, HLA-B, and HLA-C loci, 11 HLA-A-B-Cw haplotypes, 19 HLA-A-B haplotypes, 18 HLA-A-Cw haplotypes, and 24 HLA-B-Cw haplotypes with the frequencies of higher than 0.01 were revealed. The Nei's genetic distance (GD) was estimated, and the NJ dendrogram showed that Northern Han had a higher GD to Southern Han (0.233) than those to the Korean (0.138) or other Northern ethnic groups, suggesting that Northern Han had more mixed blood with the ethnic groups originally in Northeast Asia. Our results provide useful information on the further study of evolution and relationships of Chinese ethnic groups and disease association in terms of HLA class I genes.
Atrial natriuretic peptide (ANP) as well as its receptors is found in mammalian ovary and follicular cells and its function in oocyte meiotic maturation has also been reported in Xenopus, hamster and rat. But the results are controversial and the physiological mechanism of ANP on oocyte maturation is not clear, especially the relationship between gonadotrophin and ANP as well as the signal transduction, and these need further study. The present study conducted experiments to examine these questions by using drug treatment and Western blot analysis and focused on pig oocyte meiotic maturation and cumulus expansion in vitro. The results revealed that ANP could inhibited FSH-induced pig oocyte maturation and cumulus expansion and prevent the full phosphorylation of mitogen-activated protein kinase in both oocytes and cumulus cells, and that these inhibitory effects could be mimicked by 8-Br-cyclic guanosine 5'-monophosphate (8-Br-cGMP), but blocked by a protein kinase G (PKG) inhibitor KT5823. Zaprinast, a cGMP-specific phosphodiesterase inhibitor, could enhance the inhibitory effect of ANP on oocyte maturation. A specific analogue of ANP, C-ANP-(4-23), which binds to the natriuretic peptide receptor-C (NPRC), had no effect in either FSH-induced or spontaneous oocyte maturation. Treatment with forskolin, a stimulator of adenylate cyclase, had a biphasic effect; 44 h treatment induced cumulus expansion but inhibited oocyte maturation while 2 h treatment induced maturation of cumulus-enclosed oocytes (CEOs). Both ANP and C-ANP-(4-23) could inhibit the effect of forskolin on CEO maturation, and these inhibitory effects of ANP/C-ANP-(4-23) could be blocked by preincubation with pertussis toxin (PT), consistent with mediation by a Gi protein(s) in the cumulus cells. All these results suggest that ANP is a multifunctional regulator of FSH and forskolin on pig CEO maturation by two signalling mechanisms: one is via a cGMP/PKG pathway, the other is via NPRC receptors in cumulus cells and the activation of the PT-sensitive Gi protein(s).
A Bombyx mori nucleopolyhedrovirus (BmNPV) mutant with chi- tinase gene (chiA) deletion (BmchiA-) was constructed. The effects of chiA deletion on virus infected BmN cells and silkworm larvae were examined. The egfp gene expression under the control of the chiA promoter, in BmchiA- -infected BmN cells could be detected as early as 8 h p.i. The fluorescence reached its peak at 48 h p.i., and was prevalent until the cell lysis. Cytopathological comparison of the cells infected with wild type and mutant viruses showed that deletion of chiA could evidently delay the cell lysis. SDS-PAGE analysis suggested that the content of polyhedrin in BmchiA- -infected cells at 7 days p.i. was about 28% of the total cellular proteins, about 7% lower than that in wild-type BmNPV virus-infected cells. The symptoms of B. mori larvae infected with BmchiA- were different from those of wild-type BmNPV-infected larvae, e.g., clear haemolymph and less degradation of the body after larval death.
We report on the results of an exhaustive study of the valence electronic structure of norbornane (C(7)H(12)), up to binding energies of 29 eV. Experimental electron momentum spectroscopy and theoretical Green's function and density functional theory approaches were all utilized in this investigation. A stringent comparison between the electron momentum spectroscopy and theoretical orbital momentum distributions found that, among all the tested models, the combination of the Becke-Perdew functional and a polarized valence basis set of triple-zeta quality provides the best representation of the electron momentum distributions for all of the 20 valence orbitals of norbornane. This experimentally validated quantum chemistry model was then used to extract some chemically important properties of norbornane. When these calculated properties are compared to corresponding results from other independent measurements, generally good agreement is found. Green's function calculations with the aid of the third-order algebraic diagrammatic construction scheme indicate that the orbital picture of ionization breaks down at binding energies larger than 22.5 eV. Despite this complication, they enable insights within 0.2 eV accuracy into the available ultraviolet photoemission and newly presented (e,2e) ionization spectra, except for the band associated with the 1a(2) (-1) one-hole state, which is probably subject to rather significant vibronic coupling effects, and a band at approximately 25 eV characterized by a momentum distribution of "s-type" symmetry, which Green's function calculations fail to reproduce. We note the vicinity of the vertical double ionization threshold at approximately 26 eV.
Two new steryl esters with a polyhydroxylated ergostane-type nucleus, 3beta,5alpha-dihydroxy-(22E,24R)-ergosta-7,22-dien-6beta-yl oleate (1) and 3beta,5alpha-dihydroxy-(22E,24R)-ergosta-22-en-7-one-6beta-yl oleate (2), were isolated from the fruiting bodies of the basidiomycete Tricholomopsis rutilans along with three known sterols (3, 4, and 5). The structures of compounds 1 and 2 were established on the basis of spectroscopic means and chemical methods.