Biomedical subjects

W Ma

Publications and source records attributed to W Ma.

At least 145 records · Page 8Linked to original sources

PubMed2000

[Clinical diagnosis of apical hypertrophic cardiomyopathy].

OBJECTIVE: To evaluate the clinical features of apical hypertrophic cardiomyopathy (AHCM) and the value of ECG for a reliable clinical diagnosis as compared with two-dimensional echocardiography. METHODS: 29 cases with AHCM were studied by with clinical features, ECG, echocardiography, myocardial scanning, coronary angiography and left ventriculography (LVG). RESULTS: The major clinical feature of AHCM was myocardial ischemia; ECG showed increased R amplitude and inverted T in chest leads. The increase of R amplitude was in such a pattern that RV(4)>or=RV(5) > RV(3). Thickening of left ventricular apical wall was found with echocardiography and radionuclide myocardial scanning. Exercise electrocardiogram showed myocardial ischemia in 20 cases. LVG and coronary angiography demonstrated apical hypertrophic cardiomyopathy with normal coronary arteries in 16 cases. CONCLUSION: The characteristic inverted T waves and increased R wave amplitude with RV(4)>or=RV(5 > RV3) in the ECG are the important signs for clinical diagnosis of AHCM.

Adult↗

PubMed2000

[Induction of antibody to hepatitis C virus E2 antigene can be enhanced by coinjection of interleukin-2 and HCV E2 expression plasmid].

OBJECTIVE: To investigate the modulation effect of interleukin-2 (IL-2) gene on the immune response to hepatitis C virus (HCV) E2 gene when codelivered. METHODS: An expression vector of HCV E2 gene (p3E2) was constructed and its expression was detected in mammalian cells by transient expression. BALB/c mice were given injections of p3E2 only or together with IL-2 gene intraepidermally once or twice, and the induced humoral immune responses were evaluated. RESULTS: Immunohistochemistry showed that the constructed vector was successfully expressed in mammalian cells. Mice immunized with both p3E2 and IL-2 genes exhibited a significant increase in the production of anti-HCV E2 antibody compared with the mice immunized only with p3E2. CONCLUSION: Humoral immune responses of BALB/c mice to HCV E2 antigen can be enhanced when HCV E2 gene and IL-2 gene are coinjected.

Adjuvants, Immunologic↗

PubMed2000

[Combined five tumor markers in detecting primary hepatic carcinoma].

OBJECTIVE: To increase the detection rate of primary hepatic carcinoma (PHC) and to diagnose PHC earlier. METHODS: AFP was combined with r-glutamyle transpeptidase (r-GT), alpha-fucosidase (AFU), tumor necrosis factor-alpha (TNF-alpha) and DR-70. RESULTS: The positive detection rate of PHC negative AFP with combined four markers was 9.4%. The total positive detection rate of PHC with combined five tumor markers reached 98.0% which was significantly higher than that with AFP (P < 0.01). CONCLUSIONS: The positive detection rate of PHC can be increased by combined five tumor markers. It is helpful in diagnosing PHC earlier and can differentiate PHC from liver cirrhosis.

Biomarkers, Tumor↗

PubMed2000

[The relationship of expression of CD44v6 with metastasis and prognosis in breast cancer].

OBJECTIVE: To study the relationship of expression of CD44v6 with metastasis and prognosis in breast cancer. METHODS: The expression of CD44v6 protein in 78 paraffin and 37 fresh specimens of breast carcinomas was detected with immunohistochemistry (IHC). The expression of CD44v6 mRNA in 37 fresh specimens of breast carcinoma was detected with RT-PCR. The correlation of tumor size, TNM stage, status of axillary lymph node, tissue grade, prognosis and CD44v6 expression in breast cancer was analyzed to compare the sensitivity of the two methods. RESULTS: The expression of CD44v6 in breast cancer was correlated to metastasis of the axillary lymph node, tumor size and TNM stage. It was an important factor affecting survival of patients with breast cancer. Positive expressive rates of CD44v6 protein and mRNA were 70.3% and 59.5% respectively in 37 specimens of fresh carcinoma tissues (P > 0.05). CONCLUSIONS: The expression of CD44v6 is closely related to metastasis and prognosis in breast cancer, and the sensitivity to detect CD44v6 expression shows no significant difference between IHC and RT-PCR.

Adult↗

PubMed2000

[Simultaneously corneal laceration repair, traumatic cataract removal and intraocular lens implantation].

OBJECTIVE: The study aimed to evaluate the outcome of patients who undrwent simultaneously corneal laceration repair, cataract extraction and posterior chamber lens implantation. METHODS: Traumatic cataract extraction and posterior chamber intraocular lens (PC IOL) implantation were performed in 36 eyes of 36 cases with corneal laceration. YAG laser was the postoperative procedure for embrane before the lens and after cataract. Penetrating keratoplasty was performed for central cicatrice of cornea. All the patients have been followed up for 3-12 months. RESULTS: The postoperative visual acuity s.c. was 0.1-0.3 in 8 cases(22.8%), 0.4-0.5 in 14 cases (40%) 0.6-0.8 in 13 cases (37.1%) on following up. There were no serious complication attributable to PC IOL implantation. CONCLUSION: As long as the range of surgical indication was known well, PC IOL implantation can get good clinical effects at the time of primary repair.

Adolescent↗

PubMed2000

[Erythroid differentiation denucleation factor: a family of erythroid regulators for mammalian erythroid terminal differentiation/tumor suppression and the cloning of their related genes].

The role of regulation of erythroid differentiation denucleation factor(EDDF) on mammalian erythroid differentiation and myeloma cell malignancy as well as cloning of their stage related genes were serially studied. Through a series of cybrid and hybridization experiments between mammalian erythroid cells and erythroleukemia or non-erythroid myeloma cells, we have demonstrated a novel family of erythroid regulators(EDDFs) in the mammalian differentiating erythroblasts which with an active peak occurred concomitantly with marked decreases in DNA, RNA and the nuclear anchoring vimentin-IF, but increased in hemoglobin synthesis in cytoplasm prior to the denucleation process during terminal differentiation. The results of cell fusion experiments verified that the supplement of regulators(EDDFs) was critical to the recovery of the originally lost features of terminal differentiation and the reversion of malignant phenotype of tumor cells. Here we showed that the erythroid regulator family EDDFs were essential regulators for the sequential expression of stage related genes of erythroid terminal differentiation, and for the redifferentiation of tumor cells to express the originally inactive globe genes, repressed the oncogenes, and vimentin-IF system, thus initiated nuclear condensation and denucleation. The EDDF gene family consisted of MEDDF, HEDDF-1, HEDRF-1, HEDRF-2 and HCNBP-1 were cloned. All were novel cDNA sequences that have been searched and registered in GenBank. They expressed varying in a stage specific manner, and acted on corresponding genes of terminal differentiation.

Activins↗

PubMed2000

[Ganciclovir induces apoptosis of rat C6 glioma cell transduced with HSV-tk gene].

OBJECTIVE: To observe whether apoptosis could be induced by ganciclovir (GCV) in the herpes simplex virus-thymidine kinase gene-ganciclovir system (HSV-tk-GCV system) gene therapy for glioma. METHODS: Transduced C6/tk glioma cell as treated group, wild C6 cell as control group, were studied with morphology, gel-electrophoresis of DNA fragment analysis, fluoroscopy, and flow cytometric study before or after exposed to GCV, and apoptosis of transduced C6/tk glioma cell was ascertained. RESULTS: When C6/tk cell was treated with GCV at 5 micrograms/ml for 72 hours, cell apoptosis occurred. Typical apoptotic morphological features included cell shrinkage, condensation, and margination of nuclear chromatin were showed by light and electron microscopy, condensed nuclear chromatin and the fragment of nuclei were demonstrated by fluoroscopy, DNA ladder was showed by DNA fragment analysis, apoptotic peak was identified by flow cytometric study. The apoptotic cells accounted for 23% of the cell population. Apoptosis was not observed in control group treated by GCV. CONCLUSIONS: The apoptosis of transduced C6/tk glioma was induced by GCV, which fit in with the basis of HSV-tk-GCV gene therapy for glioma.

Animals↗

PubMed2000

[CD45-gating for flow cytometric immunophenotyping of leukemia].

OBJECTIVE: To establish a reliable and rapid multiparameter flow cytometric approach for leukemia immunophenotyping. METHODS: Leukemia blast cells which exhibit a character of low CD45 expression and low side scatter density are easily recognized by "CD45-SSC gating", we measured 46 patients and 3 normal persons of immunophenotyping by this gating method as well as traditional forwardscatter-side scatter (FSC-SSC) gating method. RESULTS: 5 of 46 immunophenotypic results from "FSC-SSC gating" showed false diagnosis, which were corrected by "CD45-SSC gating". Further, immunophenotypic mapping of 46 different acute leukemia were obtained by "CD45-SSC gating" and three-color staining, The expression of related antigen could be readily observed. CONCLUSIONS: "CD45-SSC gating" is a reliable and easy method to subclassify leukemia. Three-color staining, which is able to analyze the expression among two related antigens, not only be helpful in leukemia diagnosis but also contribute to study the occurrence, development and prognosis of diseases.

Adolescent↗

PubMed1999

Partial sciatic nerve transection induced tyrosine hydroxidase immunoreactive axon sprouting around both injured and spared dorsal root ganglion neurons which project to the gracile nucleus in middle-aged rats.

After partial sciatic nerve transection (PSNT), sympathetic axons sprout into the lumbar dorsal root ganglia (DRG), a phenomenon implicated in neuropathic pain. We asked whether sympathetic sprouting is directed to injured or spared DRG neurons and whether these neurons project to the gracile nucleus. Using combined fluorescent dye tracing and tyrosine hydroxylase (TH) immunohistochemistry, we found that 4 weeks after PSNT in rats 8-10 months old, 51% of the neurons surrounded by TH-immunoreactive (IR) axons were spared, while 43% were injured. Seventy-nine percent projected to the gracile nucleus. Sympathetic sprouting induced by PSNT is not directed preferentially to injured or spared DRG neurons, but does show a preference for DRG neurons projecting to the gracile nucleus.

Aging↗

PubMed1999

A translation repressor element resides in the 3' untranslated region of human p53 mRNA.

The 3' untranslated region of human p53 mRNA represses translation both in vitro and in vivo. Here, we identify a cis-acting 66-nucleotide U-rich sequence in the human p53 mRNA 3' untranslated region that mediates translational repression. Using UV cross-linking, we detect a 40 kDa protein that interacts specifically with the p53 3'UTR containing the repressor element. Enhanced translation of p53 mRNA contributes to the accumulation of p53 protein in cells exposed to gamma-radiation and could be a consequence of relieving the inhibition mediated by the repressor element.

3' Untranslated Regions↗

PubMed1999

Positive identification of the puberty-accelerating pheromone of the house mouse: the volatile ligands associating with the major urinary protein.

Five structurally diverse small ligands, all binding to the major urinary protein (MUP) of the male house mouse, show individually puberty-accelerating pheromonal activity in the recipient females. A recombinant MUP (identical structurally to the natural protein) has shown no biological activity. While four of these ligands were previously implicated in oestrus synchronization (Whitten effect), the same chemosignals now appear responsible for both sexual maturation and cycling in adult females.

Animals↗

PubMed1999

Human endothelial cells augment early CD40 ligand expression in activated CD4+ T cells through LFA-3-mediated stabilization of mRNA.

Human endothelial cells (EC) augment CD40 ligand (CD40L) expression on PHA-activated CD4+ T cells at early times (e.g., 4-6 h). Fixed EC, devoid of mRNA, are comparable to living EC in their capacity to augment early CD40L expression on CD4+ T cells. Fixed EC increase T cell mRNA expression of both IL-2 and CD40L compared with PHA alone at 6 h. EC are unable to increase the rate of transcription of CD40L compared with PHA alone as measured with a promoter-reporter gene, although they do increase transcription of an IL-2 promoter-reporter gene. Fixed EC prolong the half-life of CD40L mRNA >2-fold. Inclusion of anti-human LFA-3 (CD58) mAb or pretreatment of EC with an LFA-3 antisense oligonucleotide blocks EC-induced increases in CD40L expression, whereas mAb to ICAM-1 or pretreatment with ICAM-1 antisense oligonucleotide does not. Moreover, mAb to LFA-3 reverses the capacity of EC to prolong the half-life of CD40L mRNA, whereas mAb to ICAM-1, even in combination with mAb to ICAM-2, does not. We conclude that EC use LFA-3 to increase early CD40L protein expression on newly activated CD4+ T cells by stabilizing CD40L mRNA.

Adjuvants, Immunologic↗

PubMed1999

Characterization of rat spinal cord neurons cultured in defined media on microelectrode arrays.

Previous efforts to utilize mammalian spinal cord neurons as biosensor elements have relied on neuronal: glial co-cultures maintained in serum-containing media. We have examined the feasibility of culturing primary spinal cord neurons in serum-free medium, modified for neuronal longevity, on fabricated microelectrode arrays. Embryonic day 15 rat spinal cord cells were plated on trimethoxysilyl-propyldiethylenetriamine coated microelectrode arrays comprised of gold recording sites passivated with silicon nitride. Immunocytochemistry was performed to verify the presence of neurons and quantitatively assess astrocytes using antibodies against glial fibrillary acidic protein on the silicon nitride substrates. Modifications to culture media enabled viable neuronal culture to extend from approximately 14 days in vitro (DIV) to 40 DIV on the arrays containing only 1.1 +/- 0.5% (mean +/- SEM) astrocytes. Extracellular recording revealed tetrodotoxin-sensitive spontaneous electrical activity from the enriched neuronal culture. Threshold detection of extracellular potentials showed an increase in spike rate as a function of glutamate concentration with neurotoxicity at elevated levels. This approach suggests that functional measures related to biosensor applications, pharmacological screening, or the evaluation of neurological disease models can be implemented in a defined culture system.

Action Potentials↗

PubMed1999

Activated neutrophils induce hyperpermeability and phosphorylation of adherens junction proteins in coronary venular endothelial cells.

The endothelial adherens junction is formed by complexes of transmembrane adhesive proteins, of which beta-catenin is known to connect the junctional protein vascular endothelial (VE)-cadherin to the cytoskeleton and to play a signaling role in the regulation of junction-cytoskeleton interaction. In this study, we investigated the effect of neutrophil activation on endothelial monolayer integrity and on beta-catenin and VE-cadherin modification. Treatment of cultured bovine coronary endothelial monolayers with C5a-activated neutrophils resulted in an increase in permeability as measured by albumin clearance across the monolayer. Furthermore, large scale intercellular gap formation was observed in coincidence with the hyperpermeability response. Immunofluorescence analysis showed that beta-catenin and VE-cadherin staining changed from a uniform distribution along the membrane of control cells to a diffuse pattern for both proteins and finger-like projections for beta-catenin in neutrophil-exposed monolayers. Correlatively, there was an increase in actin stress fiber formation in treated cells. Finally, beta-catenin and VE-cadherin from neutrophil-treated endothelial cells showed a significant increase in tyrosine phosphorylation. Our results are the first to link neutrophil-mediated changes in adherens junctions with intercellular gap formation and hyperpermeability in microvascular endothelial cells. These data suggest that neutrophils may regulate endothelial barrier function through a process conferring conformational changes to beta-catenin and VE-cadherin.

Animals↗

PubMed1999

Extracellular sodium regulates airway ciliary motility by inhibiting a P2X receptor.

The mucociliary system is responsible for clearing inhaled particles and pathogens from the airways. This important task is performed by the beating of cilia and the consequent movement of mucus from the lungs to the upper airways. Because ciliary motility is enhanced by elevated intracellular calcium concentrations, inhibition of calcium influx could lead to disease by jeopardizing mucociliary clearance. Several hormones and neurotransmitters stimulate ciliary motility, one of the most potent of which is extracellular ATP (ATP0), which acts by releasing calcium ions from internal stores and by activating calcium influx. Here we show that, in airway ciliated cells, extracellular sodium ions (Na+(0)) specifically and competitively inhibit an ATP0-gated channel that is permeable to calcium ions, and thereby attenuate ATP0-induced ciliary motility. Our finding points to a physiological role for Na+(0) in ciliary function, and indicates that mucociliary clearance might be improved in respiratory disorders such as chronic bronchitis and cystic fibrosis by decreasing the sodium concentration of the airway surface fluid in which the cilia are bathed.

Adenosine Triphosphate↗

PubMed1999

A comparison of eubacterial and archaeal structure-specific 5'-exonucleases.

The 5'-exonuclease domains of the DNA polymerase I proteins of Eubacteria and the FEN1 proteins of Eukarya and Archaea are members of a family of structure-specific 5'-exonucleases with similar function but limited sequence similarity. Their physiological role is to remove the displaced 5' strands created by DNA polymerase during displacement synthesis, thereby creating a substrate for DNA ligase. In this paper, we define the substrate requirements for the 5'-exonuclease enzymes from Thermus aquaticus, Thermus thermophilus, Archaeoglobus fulgidus, Pyrococcus furiosus, Methanococcus jannaschii, and Methanobacterium thermoautotrophicum. The optimal substrate of these enzymes resembles DNA undergoing strand displacement synthesis and consists of a bifurcated downstream duplex with a directly abutted upstream duplex that overlaps the downstream duplex by one base pair. That single base of overlap causes the enzymes to leave a nick after cleavage and to cleave several orders of magnitude faster than a substrate that lacks overlap. The downstream duplex needs to be 10 base pairs long or greater for most of the enzymes to cut efficiently. The upstream duplex needs to be only 2 or 3 base pairs long for most enzymes, and there appears to be interaction with the last base of the primer strand. Overall, the enzymes display very similar substrate specificities, despite their limited level of sequence similarity.

Archaea↗

PubMed1999

Kir 4.1 channel expression in neuroblastomaxglioma hybrid NG108-15 cell line.

To study a possible involvement of inwardly rectifying K+ 4.1 (Kir 4. 1) channels in neural cell development, RT-PCR, immunocytochemistry and whole-cell patch-clamp techniques were used to assess expression of Kir 4.1 channels in proliferating and differentiated NG108-15 cells. RT-PCR revealed co-expression of Kir 4.1 and rat ether-a-go-go-related gene (R-ERG) mRNAs in both proliferating and differentiated cells. The relative Kir 4.1 mRNA concentration increased markedly as cells progressed from undifferentiated to differentiated cells. Kir 4.1-immunoreactivity was barely detectable in undifferentiated cells, but clearly detected in differentiated cells, indicating that Kir 4.1 gene and protein expressions are developmentally regulated. However, corresponding Kir 4.1 current could not be detected in differentiated cells using whole-cell patch-clamp recording. The 'silent' channel/receptor, often found in tumor cells, may carry genetic defects, which prevent functional expression of the channel. NG108-15 may serve as unique model for studying the relationship between the expression of an ion channel gene and the electrophysiological phenotype it encodes.

Animals↗

PubMed1999

The expression of GABA(A) receptor alpha2 subunit is upregulated by testosterone in rat cerebral cortex.

The GABAergic system is sexually dimorphic in certain brain regions and can be regulated by testosterone (T). However, the contribution of T to sex-specific developmental processes in the brain is less clear. We have examined whether T regulates expression of GABA(A) receptor alpha2 subunit in the cerebral cortex of embryonic and postnatal female rats using in situ hybridization and Western blotting. We found that both alpha2 mRNA and protein levels are significantly increased by T treatment at embryonic day 20 (E20) and birth (P0). The observed modulation of the expression of GABA(A) receptor alpha2 subunit by T may be translated into changes in the levels or composition of GABA(A) receptor, either of which would be expected to alter neuronal functional response to GABA activation. As the effects of T are developmental-stage-specific, they may have an organizational impact on brain development.

Analysis of Variance↗