Biomedical subjects

Qing Chang

Publications and source records attributed to Qing Chang.

At least 19 recordsLinked to original sources

PubMed2026

GFER Represents a Target for Dual Disruption of Redox Homeostasis and Reactivation of the Immune Response in Pancreatic Adenocarcinoma.

UNLABELLED: Both metabolic dysregulation and the immunosuppressive tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) contribute to the recalcitrance of this lethal disease to treatment. Accordingly, we aimed to identify and characterize a target that elicits an anticancer response through both disrupting cancer cell redox homeostasis and increasing the immunogenicity of PDAC. First, mitochondrial metabolic dependencies in PDAC were identified by using a CRISPR-Cas9 screening system with a custom single-guide RNA library. Functional validation analyses revealed GFER, a mitochondrial FAD-dependent sulfhydryl oxidase, as an essential regulator of tumor growth. In vitro and in vivo methodologies demonstrated that GFER depletion perturbed redox homeostasis and stimulated tumor immunogenicity, including sensitization to immune checkpoint blockade. In patient-derived xenograft models of PDAC, the growth-inhibitory response induced by GFER depletion was mediated by an altered oxidative balance that released damaged mitochondrial DNA into the cytoplasm of tumor cells, leading to the activation of the cGAS-STING pathway and expression of type I IFNs. This effect was recapitulated in a mouse immunocompetent syngeneic PDAC model, in which GFER depletion suppressed tumor growth and promoted T-cell infiltration to enhance tumor-killing effects. Consequently, GFER depletion significantly increased the antitumor efficacy of immune checkpoint blockade. Overall, these findings identify GFER as a critical node for both mitochondrial redox homeostasis and immunomodulation in PDAC and reveal a therapeutic opportunity for sensitizing PDAC to immune checkpoint blockade. SIGNIFICANCE: GFER is essential for mitochondrial redox balance and suppressing tumor immunogenicity in pancreatic tumors, with the combination of GFER inhibition with immune checkpoint blockade resulting in a strong antitumor response.

Animals↗

PubMed2025

Clinical and Multiorgan Proteomics Characteristics of the Diverse Fatal Phase in Super Elderly Patients With SARS-CoV-2 Infection: A Descriptive Study.

This study aims to identify the risk factors associated with clinical outcomes and the proteomic changes in organs related to fatal SARS-CoV-2 infection within the super-elderly population. This retrospective analysis included all elderly individuals with COVID-19 admitted to the Second Medical Center of PLA General Hospital from December 2022 to January 2023. The follow-up period ended on March 30, 2023. During this time, epidemiological, demographic, laboratory, and outcome data were analyzed descriptively. Proteomic sequencing was performed on super-elderly patients who died from COVID-19 at different stages of the disease. A total of 352 elderly COVID-19 patients, with a mean age of 89.84 ± 8.54 years, were included in this study. During a median follow-up period of 98 days, 79 patients died. Deceased patients were older and more likely to have cardiovascular and cerebrovascular diseases, with a lower prevalence of lipid-lowering therapy. The number of deaths in the acute and post-acute phases were 34 and 45, respectively. Proteomics data suggest that the immune systems of patients who died in the acute phase underwent a more rapid and severe onslaught. Patients in the post-acute phase showed higher levels of viral genome replication and a more robust immune response. However, the over-activation of the immune system led to systemic organ dysfunction. Effective management of comorbidities may improve the prognosis of COVID-19 in super-elderly patients. The continuous replication of the SARS-CoV-2 virus and its subsequent impact on the immune system are critical determinants of survival time in this demographic.

Humans↗

PubMed2007

Restoration of connexin26 protein level in the cochlea completely rescues hearing in a mouse model of human connexin30-linked deafness.

Mutations in genes coding for connexin26 (Cx26) and/or Cx30 are linked to approximately half of all cases of human autosomal nonsyndromic prelingual deafness. Cx26 and Cx30 are the two major Cx isoforms found in the cochlea, and they coassemble to form hybrid (heteromeric and heterotypic) gap junctions (GJs). This molecular arrangement implies that homomeric GJs would remain in the cochlea if one of the coassembly partners were mutated resulting in null expression. We generated mice in which extra copies of the Cx26 gene were transgenically expressed from a modified bacterial artificial chromosome in a Cx30-/- background. In the absence of the Cx30 gene, Cx26 expressed from extra alleles completely restored hearing sensitivity and prevented hair cell death in deaf Cx30-/- mice. The results indicated that hybrid GJs consisting of Cx26 and Cx30 were not essential for normal hearing in mice and suggested that up-regulation of Cx26 or slowing down its protein degradation might be a therapeutic strategy to prevent and treat deafness caused by Cx30 mutations.

Animals↗

PubMed2006

An acute effect of neuregulin 1 beta to suppress alpha 7-containing nicotinic acetylcholine receptors in hippocampal interneurons.

We examined rapid effects of neuregulin (NRG) on nicotinic acetylcholine (ACh) receptors in interneurons located in the stratum radiatum of the hippocampus. Two types of response were detected by whole-cell recordings after brief pulses of ACh. One type was a rapidly rising and falling (monophasic) current that was blocked by methyllycaconitine. The other type was a similar fast response followed by a more slowly rising and falling current. The slow component of the biphasic response was resistant to methyllycaconitine. Perfusion or local application with NRG 1beta rapidly decreased fast inward ACh currents. NRG 1beta had no effect on slow responses. NRG 1beta suppression was abolished by the ErbB tyrosine kinase inhibitor PD 158780 (4-[(3-bromophenyl) amino]-6-(methylamino)-pyrido[3,4-d]pyridimine). The NRG 1beta effect was also inhibited by phalloidin and cytochalasin D. Furthermore, NRG 1beta decreased the number of surface Alexa Fluor 488 alpha-bungarotoxin binding sites. We believe that the NRG 1beta-induced inhibition of ACh currents is because of receptor internalization trigged by protein tyrosine phosphorylation. Significantly, fast nicotinic EPSCs evoked in the presence of muscarinic, ionotropic glutamate, and GABA receptors antagonists were also reduced by NRG 1beta. Thus, short-term as well as long-term effects of NRG must be taken into consideration in studies of ACh receptor-mediated synaptic efficacy in the CNS.

Acetylcholine↗

PubMed2006

Gitelman's syndrome: towards genotype-phenotype correlations?

Gitelman's syndrome (GS) is a salt-losing tubulopathy characterized by hypokalemic alkalosis with hypomagnesemia and hypocalciuria. The disease is associated with inactivating mutations in the SLC12A3 gene that codes for the thiazide-sensitive Na+-Cl- cotransporter (NCCT) that is expressed in the apical membrane of the cells lining the distal convoluted tubule (DCT). GS is relatively frequent, and more than 100 mutations scattered through SLC12A3 have been identified thus far. Although the disease is recessively inherited, up to 40% of patients are found to carry only a single mutation, instead of being compound heterozygous or homozygous. The phenotype of GS is highly heterogeneous in terms of age at presentation, and nature/severity of the biochemical abnormalities and clinical manifestations. This phenotypical heterogeneity is observed not only between all patients harbouring SLC12A3 mutations but also among family members or patients with identical mutations. In this review, we discuss the potential explanations for the failure to identify mutant alleles in SLC12A3, as well as the different mechanisms that can account for the inter- and intra-familial phenotype variability in GS, including genetic heterogeneity, position and nature of the mutations, functional consequences, compensatory mechanisms, and modifying genes.

Animals↗

PubMed2006

Functional studies of aldo-keto reductases in Saccharomyces cerevisiae.

We utilized the budding yeast Saccharomyces cerevisiae as a model to systematically explore physiological roles for yeast and mammalian aldo-keto reductases. Six open reading frames encoding putative aldo-keto reductases were identified when the yeast genome was queried against the sequence for human aldose reductase, the prototypical mammalian aldo-keto reductase. Recombinant proteins produced from five of these yeast open reading frames demonstrated NADPH-dependent reductase activity with a variety of aldehyde and ketone substrates. A triple aldo-keto reductase null mutant strain demonstrated a glucose-dependent heat shock phenotype which could be rescued by ectopic expression of human aldose reductase. Catalytically-inactive mutants of human or yeast aldo-keto reductases failed to effect a rescue of the heat shock phenotype, suggesting that the phenotype results from either an accumulation of one or more unmetabolized aldo-keto reductase substrates or a synthetic deficiency of aldo-keto reductase products generated in response to heat shock stress. These results suggest that multiple aldo-keto reductases fulfill functionally redundant roles in the stress response in yeast.

Alcohol Oxidoreductases↗

PubMed2006

Characterization of an immunodominant antigenic site on GB virus C glycoprotein E2 that is involved in cell binding.

GB virus type C (GBV-C) is a human flavivirus that may cause persistent infection, although most infected individuals clear viremia and develop antibodies to the envelope glycoprotein E2. To study GBV-C E2 antigenicity and cell binding, murine anti-E2 monoclonal antibodies (MAbs) were evaluated to topologically map immunogenic sites on GBV-C E2 and for the ability to detect or block recombinant E2 binding to various cell lines. Five competition groups of MAbs were identified. Groups I and II did not compete with each other. Group III competed with both groups I and II. Group IV did not compete with group I, II, or III. One MAb competed with all of the other MAbs, suggesting that the epitopes bound by these MAbs are intimately related. Individually, none of the MAbs competed extensively with polyclonal human convalescent antibody (PcAb); however, combinations of all five MAb groups completely blocked PcAb binding to E2, suggesting that the epitopes bound by these MAbs form a single, immunodominant antigenic site. Only group I and III MAbs detected purified recombinant E2 bound to cells in binding assays. In contrast, group II MAbs neutralized the binding of E2 to cells. Both PcAb and MAbs were conformation dependent, with the exception of one group II MAb (M6). M6 bound to a five-amino-acid sequence on E2 if the peptide included four C-terminal or eight N-terminal residues, suggesting that the GBV-C E2 protein contains a single immunodominant antigenic site which includes a complex epitope that is involved in specific cellular binding.

Amino Acid Sequence↗

PubMed2006

An 85-aa segment of the GB virus type C NS5A phosphoprotein inhibits HIV-1 replication in CD4+ Jurkat T cells.

GB virus type C (GBV-C) is an apparently nonpathogenic virus that replicates in T and B lymphocytes and is a common cause of persistent human infection. Among HIV-1-infected individuals, persistent coinfection with GBV-C is associated with prolonged survival, and infection of blood mononuclear cells or CD4+ T cells with GBV-C and HIV in vitro results in significantly reduced HIV-1 replication. To date, the viral protein(s) that lead to HIV inhibition have not been identified. The GBV-C nonstructural phosphoprotein (NS5A) is predicted to have pleotropic effects on cells, including interactions with the IFN-induced dsRNA-activated protein kinase (PKR). We studied GBV-C NS5A to determine whether it is involved in inhibition of HIV replication. GBV-C NS5A protein from an isolate that was cleared by IFN therapy did not inhibit PKR, whereas NS5A from an isolate that was not cleared by IFN-inhibited PKR function in a yeast genetic system. Both of these GBV-C NS5A proteins were expressed in a CD4+ T cell line (Jurkat), and both induced a potent, dose-dependent inhibition of HIV-1 replication, thus the effect was independent of PKR inhibition. NS5A induced the release of the chemokine SDF-1 and decreased surface expression of the HIV coreceptor CXCR4, potentially explaining the HIV inhibition. Deletion mapping of the NS5A protein found that an 85-aa region between amino acids 152 and 237 inhibits HIV-1 replication. Thus, GBV-C NS5A protein alters the cellular milieu necessary for HIV-1 replication and may provide a previously undescribed therapeutic approach for anti-HIV therapy.

CD4-Positive T-Lymphocytes↗

PubMed2006

Tissue kallikrein stimulates Ca(2+) reabsorption via PKC-dependent plasma membrane accumulation of TRPV5.

The transient receptor potential vanilloid 5 (TRPV5) channel determines urinary Ca(2+) excretion, and is therefore critical for Ca(2+) homeostasis. Interestingly, mice lacking the serine protease tissue kallikrein (TK) exhibit robust hypercalciuria comparable to the Ca(2+) leak in TRPV5 knockout mice. Here, we delineated the molecular mechanism through which TK stimulates Ca(2+) reabsorption. Using TRPV5-expressing primary cultures of renal Ca(2+)-transporting epithelial cells, we showed that TK activates Ca(2+) reabsorption. The stimulatory effect of TK was mimicked by bradykinin (BK) and could be reversed by application of JE049, a BK receptor type 2 antagonist. A cell permeable analog of DAG increased TRPV5 activity within 30 min via protein kinase C activation of the channel since mutation of TRPV5 at the putative PKC phosphorylation sites S299 and S654 prevented the stimulatory effect of TK. Cell surface labeling revealed that TK enhances the amount of wild-type TRPV5 channels, but not of the TRPV5 S299A and S654A mutants, at the plasma membrane by delaying its retrieval. In conclusion, TK stimulates Ca(2+) reabsorption via the BK-activated PLC/DAG/PKC pathway and the subsequent stabilization of the TRPV5 channel at the plasma membrane.

Amino Acid Substitution↗

PubMed2006

TBLR1 regulates the expression of nuclear hormone receptor co-repressors.

BACKGROUND: Transcription is regulated by a complex interaction of activators and repressors. The effectors of repression are large multimeric complexes which contain both the repressor proteins that bind to transcription factors and a number of co-repressors that actually mediate transcriptional silencing either by inhibiting the basal transcription machinery or by recruiting chromatin-modifying enzymes. RESULTS: TBLR1 [GenBank: NM024665] is a co-repressor of nuclear hormone transcription factors. A single highly conserved gene encodes a small family of protein molecules. Different isoforms are produced by differential exon utilization. Although the ORF of the predominant form contains only 1545 bp, the human gene occupies approximately 200 kb of genomic DNA on chromosome 3q and contains 16 exons. The genomic sequence overlaps with the putative DC42 [GenBank: NM030921] locus. The murine homologue is structurally similar and is also located on Chromosome 3. TBLR1 is closely related (79% homology at the mRNA level) to TBL1X and TBL1Y, which are located on Chromosomes X and Y. The expression of TBLR1 overlaps but is distinct from that of TBL1. An alternatively spliced form of TBLR1 has been demonstrated in human material and it too has an unique pattern of expression. TBLR1 and the homologous genes interact with proteins that regulate the nuclear hormone receptor family of transcription factors. In resting cells TBLR1 is primarily cytoplasmic but after perturbation the protein translocates to the nucleus. TBLR1 co-precipitates with SMRT, a co-repressor of nuclear hormone receptors, and co-precipitates in complexes immunoprecipitated by antiserum to HDAC3. Cells engineered to over express either TBLR1 or N- and C-terminal deletion variants, have elevated levels of endogenous N-CoR. Co-transfection of TBLR1 and SMRT results in increased expression of SMRT. This co-repressor undergoes ubiquitin-mediated degradation and we suggest that the stabilization of the co-repressors by TBLR1 occurs because of a novel mechanism that protects them from degradation. Transient over expression of TBLR1 produces growth arrest. CONCLUSION: TBLR1 is a multifunctional co-repressor of transcription. The structure of this family of molecules is highly conserved and closely related co-repressors have been found in all eukaryotic organisms. Regulation of co-repressor expression and the consequent alterations in transcriptional silencing play an important role in the regulation of differentiation.

Amino Acid Sequence↗

PubMed2006

Identification and characterization of a human monoclonal antagonistic antibody AL-57 that preferentially binds the high-affinity form of lymphocyte function-associated antigen-1.

LFA-1 (alpha(L)beta(2)) mediates cell-cell and cell-extracellular matrix adhesions essential for immune and inflammatory responses. One critical mechanism regulating LFA-1 activity is the conformational change of the ligand-binding alpha(L) I domain from low-affinity (LA), closed form, to the high-affinity (HA), open form. Most known integrin antagonists bind both forms. Antagonists specific for the HA alpha(L) I domain have not been described. Here, we report the identification and characterization of a human antibody AL-57, which binds to the alpha(L) I domain in a HA but not LA conformation. AL-57 was discovered by selection from a human Fab-displaying library using a locked-open HA I domain as target. AL-57 Fab-phage bound HA I domain-expressing K562 cells (HA cells) in a Mg(2+)-dependent manner. AL-57 IgG also bound HA cells and PBMCs, activated by Mg(2+)/EGTA, PMA, or DTT. The binding profile of AL-57 IgG on PBMCs was the same as that of ICAM-1, the main ligand of LFA-1. In contrast, an anti-alpha(L) murine mAb MHM24 did not distinguish between the HA and LA forms. Moreover, AL-57 IgG blocked ICAM-1 binding to HA cells with a potency greater than MHM24. It also inhibited ICAM-1 binding to PBMCs, blocked adhesion of HA cells to keratinocytes, and inhibited PHA-induced lymphocyte proliferation with potencies comparable with MHM24. These results indicate that specifically targeting the HA I domain is sufficient to inhibit LFA-1-mediated, adhesive functions. AL-57 represents a therapeutic candidate for treatment of inflammatory and autoimmune diseases.

Antibodies, Monoclonal↗

PubMed2006

Microdialysis measures of functional increases in ACh release in the hippocampus with and without inclusion of acetylcholinesterase inhibitors in the perfusate.

Because brain extracellular acetylcholine (ACh) levels are near detection limits in microdialysis samples, an acetylcholinesterase (AChE) inhibitor such as neostigmine is often added to microdialysis perfusates to increase ACh levels in the dialysate, a practice that raises concerns that the inhibitor might alter the results. Two experiments compared functional differences in ACh release with and without neostigmine. In the first experiment, 30-60% increases in extracellular ACh concentrations in the hippocampus were evident during food-rewarded T-maze training with 20-500 nm neostigmine in the perfusate but no increases were seen without neostigmine. In the second experiment, 78% increases in ACh release in the hippocampus were seen after injections of the GABA(A) receptor antagonist, bicuculline, into medial septum only if neostigmine (50 nm) was included in the perfusate. These findings suggest that, in the hippocampus, endogenous brain AChEs are very efficient at removing extracellular ACh, obscuring differences in ACh release in these experiments. Therefore, inclusion of AChE inhibitors in the microdialysis perfusate may be necessary under some conditions for observations of functional changes in release of ACh in the hippocampus.

Acetylcholine↗

PubMed2006

Prevalence of the metabolic syndrome and its relation to cardiovascular disease in an elderly Chinese population.

OBJECTIVES: This study sought to assess the prevalence of the metabolic syndrome (MetS) and its association with cardiovascular disease (CVD) in elderly Chinese people. BACKGROUND: The information available about the prevalence of MetS based on the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF) in China is limited. METHODS: We conducted a population-based cross-sectional study in an urban Beijing sample of 2,334 participants age 60 to 95 years (943 men, 1,391 women). The CVD included diagnosed coronary heart disease (CHD), stroke, and peripheral arterial disease (PAD). RESULTS: The prevalence of MetS by the NCEP criteria was 30.5% (17.6% in men, 39.2% in women). Use of the new IDF definition significantly increased the prevalence to 46.3% (34.8% in men, 54.1% in women). Odds ratios (OR) for CHD, stroke, PAD, and CVD in those with MetS using the NCEP criteria were 1.43 (95% confidence interval [CI] 1.18 to 1.74), 1.45 (95% CI 1.14 to 1.85), 1.47 (95% CI 1.18 to 1.84), and 1.50 (95% CI 1.25 to 1.81), respectively. Corresponding ORs using new IDF criteria were 1.69 (95% CI 1.40 to 2.02), 1.58 (95% CI 1.26 to 2.00), 1.42 (95% CI 1.14 to 1.76), and 1.73 (95% CI 1.46 to 2.07), respectively. Those who met the IDF but not the NCEP criteria (n = 436, 18.7%) had significantly elevated ORs for CHD (1.66, 95% CI 1.31 to 2.10) and stroke (1.53, 95% CI 1.13 to 2.06). CONCLUSIONS: The MetS is highly prevalent in elderly people in Beijing, particularly among women. Individuals with MetS defined by either criteria are at significantly elevated ORs for CHD, stroke, and PAD. The IDF criteria seem to be better suited than the NCEP criteria for screening and estimating risk of MetS in Chinese people.

Aged↗

PubMed2006

Connexin29 is highly expressed in cochlear Schwann cells, and it is required for the normal development and function of the auditory nerve of mice.

Connexins (Cxs) are a family of protein subunits constituting gap junctions, which facilitate exchanges of molecules important for cellular signaling and metabolic activities intercellularly or between different regions of the cytoplasm in the same cells. Mutations in Cxs are the major cause of nonsyndromic childhood deafness, which are mostly found in Cx26 and Cx30 expressed in cochlear supporting cells and fibrocytes. So far, little is known about the functional contribution of Cxs in other types of cochlear cells. Here, we show that Cx29 was highly expressed in the cochlea. The developmental expression time course of Cx29 was similar to that of a myelin marker [myelin associate glycoprotein (MAG)]. Immunolabeling identified Cx29 exclusively in the Schwann cells myelinating the soma and fiber of spiral ganglion (SG) neurons. The absence of the Cx29 gene in mice (Cx29(-/-) mice), with a penetrance of approximately 50%, caused a delay in the maturation of hearing thresholds, an early loss of high-frequency sensitivities, a prolongation in latency and distortion in the wave I of the auditory brainstem responses, and elevated sensitivity to noise damages. The morphology of sensory hair cells and otoacoustic emissions that depend on the integrity of hair cells were normal in Cx29(-/-) mice. In contrast, decreases in MAG expression and severe demyelination at the soma of SG neurons were found in Cx29(-/-) mice. Our findings demonstrated the requirement of Cx29 for normal cochlear functions and suggest that Cx29 is a new candidate gene for studying the auditory neuropathy.

Animals↗

PubMed2006

Inhibition of metastatic progression of SSTR2 gene transfection mediated by adenovirus in human pancreatic carcinoma cells.

The inhibition of metastatic progression of Somatostatin receptor type 2 (SSTR2) gene transfection mediated by adenovirus in human pancreatic carcinoma cells and the mechanisms involved in this effect were studied. The full-length human SSTR2 cDNA was introduced into the pancreatic cancer cell line BXPC-3 by adenovirus-mediated transfection. Stable expression of mRNAs and protein of SSTR2 was detected by RT-PCR and Western-blot. The Matrigel-coated Transwell was used to detect the migratory and invasive ability of SSTR2-expressing cells, Adv-GFP control cells and mock control cells. Furthermore, the expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) was detected by RT-PCR in these cells. The stable expression of SSTR2 was detected in BXPC-3 transfected by Adv-GFP-SSTR2. A dramatic decrease of BXPC-3 expressing sst2 cells migrating through a Matrigel-coated filter was observed, as compared with Adv-GFP control and mock control cells (P < 0.01). Moreover, the expression of MMP-2 mRNA was significantly reduced in the SSTR2-expressing cells and conversely the expression of TIMP-2 mRNA was significantly increased in the SSTR2-expressing cells when compared with the Adv-GFP control and mock control (P < 0.01). The expression of reintroduced human SSTR2 gene in BXPC-3 cells by Adv-GFP-SSTR2 had the anti-migratory and anti-invasive effects, and the mechanisms involved in this effect may be due to the down-regulated expression of MMP-2 and up-regulated expression of TIMP-2.

Adenoviridae↗

PubMed2006

Transfection of antisense oligodeoxynucleotide inhibits heparanase gene expression and invasive ability of human pancreatic cancer cell in vitro.

Extracellular matrix (ECM) degradation is an essential step that allows tumor cells to penetrate a tissue barrier and become metastatic. Heparanase (HPSE) is an endoglycosidase that specifically degrades heparin sulfate proteoglycans (HSPG), a chief component of ECM. HPSE is not expressed in normal epithelial cells but can be detected in a variety of human carcinomas including pancreatic cancer. In the present study, human pancreatic cancer cell line Panc-1 was transfected with HPSE antisense oligodeoxynucleotide (AS-ODN) in vitro, then the inhibitory effect of AS-ODN on HPSE gene expression and invasive ability of Panc-1 cells in vitro was examined. The HPSE mRNA and protein expression of Panc-1 cells transfected with AS-ODN was significantly inhibited. However, there were no marked inhibitory effects in Panc-1 cells treated with nonsense oligodeoxynucleotide (NS-ODN). Moreover, a modified Boyden chamber assay demonstrated that transfection with HPSE AS-ODN significantly inhibited invasive potential of Panc-1 cells in vitro after AS-ODN transfection. This suggests that HPSE AS-ODN may contribute to the inhibition of HPSE mRNA and protein expression, and results in a decrease of the invasive ability of Panc-1 in vitro.

Cell Line, Tumor↗

PubMed2006

Evaluation of normal fetal left cardiac function by tissue Doppler imaging.

To explore the feasibility of using tissue Doppler imaging technique for the evaluation of fetus's left ventricular diastolic function, and to confirm its reliability by comparing it with traditional methods, this study examined 61 pregnant women in whom satisfactory images were obtained of fetal echocardiography. The peak velocity of blood stream were measured, including E, A and E/A at mitral valve orifice on the four chamber view with pulse wave. And then tissue Doppler imaging mode was employed to measure the velocity of mitral valve annulus including Ea, Aa, Sa and Ea / Aa. Correlation analysis was conducted between the velocity of orifice and that of annulus in terms of gestation age. And then correlation analysis was performed between above data and gestation ages. A positive correlation was found between the velocity of orifice and that of annulus, and the velocity increased with the gestation age. The change was the most significant between the 28th and the 34th week of gestation age. Our study showed that it is feasible to evaluate the fetus's left ventricular diastole function by tissue Doppler imaging. Its stability can avoid the influence of fetal heart rates and preload.

Adult↗

PubMed2006

Effect of antisense hypoxia-inducible factor 1alpha on progression, metastasis, and chemosensitivity of pancreatic cancer.

OBJECTIVES: The aim of the study was to observe the effect of antisense hypoxia-inducible factor 1alpha (HIF-1alpha) on progression, metastasis, and chemosensitivity of pancreatic cancer. METHODS: BxPc-3 cells transfected with antisense HIF-1alpha plasmid were exposed to 0.5% O2 for 4 hours. Expressions of HIF-1alpha, survivin, and beta1 integrin were detected by reverse transcriptase -polymerase chain reaction and Western blotting. Growth inhibition rates and apoptosis rates of BxPc-3 cells under different dosages of chemotherapy agents (5-fluorouracil, doxorubicin, and gemcitabine) were measured by MTT colorimetric assay and flow cytometry. The migration of BxPc-3 cells was assayed using transwell cell culture chambers. Subcutaneous transplantation of BxPc-3 cells in nude mice for 8 weeks was to assess progression and metastasis of pancreatic cancer. RESULTS: Expression of HIF-1alpha was obviously down-regulated, and at the same time, survivin and beta1-integrin expressions were markedly down-regulated in the experimental group (P < 0.05). Higher dosages (100, 200, and 400 mg/L of 5-fluorouracil; 0.05, 0.075, and 0.1 mg/L of doxorubicin; and 10(-9), 10(-8), and 10(-7) mol/L of gemcitabine) caused a greater increase of inhibition in the experimental group than in control (P < 0.05). The number of migrated BxPc-3 cells in the experimental group was far less than in control (P < 0.05). In vivo, the tumor size and weight in the experimental group were significantly lower than those in control (P < 0.05). CONCLUSION: Our data demonstrate that antisense HIF-1alpha inhibits expressions of survivin and beta1 integrin, enhancing apoptosis in human pancreatic cancer cells and restraining the progression and metastasis of pancreatic cancer. Therefore, HIF-1alpha may play a very important role in progression, metastasis, and chemosensitivity of human pancreatic cancer. Blocking HIF-1alpha in pancreatic cancer cells may offer an avenue for gene therapy.

Animals↗