Search PubMed⌕ Search

Biomedical subjects

R Yang

Publications and source records attributed to R Yang.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Rapid detection of enterohemorrhagic Escherichia coli in food with multiplex PCR assay].

Rapid detection of enterohemorrhagic Escherichia coli (EHEC) in food was achieved by using multiplex PCR assay. The assay was designed to amplify the 1109, 302 and 228 bp regions of corresponding virulence genes eaeA, hlyAB, slt1 and/or slt2, by using specific primers for each one reaction. In 60 EHEC and other strains, the above three virulence gene sequences were co-amplified from DNA isolated from 12 EHEC O157:H7 strains, 1 O26:H11 strain and 1 O111:H8 strain; eaeA sequence was amplified from DNA isolated from 2 EAEC strains; slt1/2 sequence was amplified from DNA isolated from 1 VTEC strain. No specific amplification product was produced from other 43 non-EHEC strains. For the detection of EHEC in food, results could be obtained within 8 hrs, and the sensitivity of assay was less than or equal to 1.6 cfu/g(ml) of food. The method was applied to 126 food samples, and EHEC was detected in 3 samples.

Animals↗
PubMed2001

[ATR-FTIR studies on the packing film].

FTIR and ATR-FTIR of the packing film have been studied. The dimension of thickness is about 0.034 m/m, the right and wrong sides of this packing film is composed of polypropylene and polyethylene glycol terephthalate, respectively.

English Abstract↗
PubMed2000

The aberrant fusion proteins PML-RAR alpha and PLZF-RAR alpha contribute to the overexpression of cyclin A1 in acute promyelocytic leukemia.

Cyclin A1 is a newly discovered cyclin that is overexpressed in certain myeloid leukemias. Previously, the authors found that the frequency of cyclin A1 overexpression is especially high in acute promyelocytic leukemia (APL). In this study, the authors investigated the mechanism of cyclin A1 overexpression in APL cells and showed that the APL-associated aberrant fusion proteins (PML-retinoic acid receptor alpha [PML-RAR alpha] or PLZF-RAR alpha) caused the increased levels of cyclin A1 in these cells. The ectopic expression of either PML-RAR alpha or PLZF-RAR alpha in U937 cells, a non-APL myeloid cell line, led to a dramatic increase of cyclin A1 messenger RNA and protein. This elevation of cyclin A1 was reversed by treatment with all-trans retinoic acid (ATRA) in cells expressing PML-RAR alpha but not PLZF-RAR alpha. ATRA also greatly reduced the high levels of cyclin A1 in the APL cell lines NB4 and UF-1. No effect of ATRA on cyclin A1 levels was found in the ATRA-resistant NB4-R2 cells. Further studies using ligands selective for various retinoic acid receptors suggested that cyclin A1 expression is negatively regulated by activated RAR alpha. Reporter assays showed that PML-RAR alpha led to activation of the cyclin A1 promoter. Addition of ATRA inhibited PML-RAR alpha-induced cyclin A1 promoter activity. Taken together, our data suggest that PML-RAR alpha and PLZF-RAR alpha cause the high-level expression of cyclin A1 seen in acute promyelocytic leukemia. (Blood. 2000;96:3894-3899)

Cell Division↗
PubMed2000

Ultrastructural localization of gustducin immunoreactivity in microvilli of type II taste cells in the rat.

Gustducin is a transducin-like G protein (guanine nucleotide-binding protein) that is expressed in taste bud cells. Gustducin is believed to be involved in bitter and possibly sweet taste transduction. In the present study, we demonstrate that a subset of type II cells displays immunoreactivity to antisera directed against gustducin in taste buds of rat circumvallate papilla. Immunogold particles are present both in the microvilli and cytoplasm of the immunoreactive cells. Quantitative analysis of the data suggests that the number of colloidal gold particles (P<0.001) and nanogold particles (P<0.01) in the immunoreactive type II cells are much greater than in type I cells. There are also approximately 2.5 times (P<0.05) as many colloidal gold particles associated with the microvilli versus the cytoplasm in the immunoreactive type II cells. The ultrastructural distribution of gustducin immunoreactivity is consistent with its proposed role in the initial events of sensory transduction by gustatory receptor cells.

Animals↗
PubMed2000

Taste cells with synapses in rat circumvallate papillae display SNAP-25-like immunoreactivity.

SNAP-25 is a 25 kDa protein believed to be involved in the processes of membrane fusion and exocytosis associated with neurotransmitter release. In the present study we present evidence that SNAP-25-like immunoreactivity can be used as a marker for taste cells with synapses in rat circumvallate papillae. SNAP-25 immunoreactivity is present in most intragemmal nerve processes and a small subset of taste cells. Intense immunoreactivity is associated with the nerve plexus located below the base of the taste bud. Of a total of 87 taste cells with synapses onto nerve processes, 80 of the presynaptic taste cells had SNAP-25 immunoreactivity. The association of SNAP-25 immunoreactivity with taste cells possessing synapses suggests that these cells may be gustatory receptor cells. Because this SNAP-25 antibody can label taste cells with synapses, it may also serve as a useful tool for future studies correlating structure with function in the taste bud.

Animals↗
PubMed2000

[Zinc protective effects on pig retinal pigment epithelial cell damage of lipid peroxide induced by 2450 MHz microwave].

To observe the lipid peroxide damage in the cultured pig retinal pigment epithelial cell(RPE) induced by microwave and the protective effects by zinc (Zn). RPE cells were divided into 3 groups in terms of microwave intensity(the group of 10, 20 and 30 mW.cm-2) and each group was exposed to microwave for 1 hour. After adding ZnSO4 into DMEM culture fluid, the group of 30 mW.cm-2 was exposed to microwave. The activity of SOD and the content of MDA were measured. The results showed that the activity of SOD decreased significantly compared with the control group(P < 0.001). The content of MDA increased significantly compared with the control group(P < 0.001). Administration of Zn alleviated the increase of MDA and decrease of SOD. In the experiment, 2450 MHz microwave induces the lipid peroxide damage in RPE cells. Zn can enhance the antioxidation ability of cells and alleviate the damage to some extent.

Animals↗
PubMed2000

Application of cDNA microarrays in determining molecular phenotype in cardiac growth, development, and response to injury.

BACKGROUND: Normal myocardial development and the tissue response to cardiac stress are accompanied by marked changes in gene expression; however, the extent of these changes and their significance remain to be fully explored. We used cDNA microarrays for gene expression profiling in rat cardiac tissue samples to study developmental transitions and the response to myocardial infarction (MI). METHODS AND RESULTS: Microarrays with rat cDNAs for 86 known genes and 989 anonymous cDNAs obtained by molecular subtraction (representational difference analysis) of mRNA from sham-operated and 6-week post-MI samples were used in 2-color hybridization experiments. Twelve known genes previously associated with myocardial development were identified together with 10 uncharacterized expressed sequence tags and 36 genes not previously associated with cardiac development. After MI, genes associated with myocardial stress and wound healing exhibited differences in magnitude and expression kinetics, and 14 genes not previously associated with MI were identified. In situ hybridization revealed mRNA localization characteristic of wound healing and vascular and cardiomyocyte reactivity. CONCLUSIONS: Tissue analysis of gene expression with cDNA microarrays provides a measure of transcriptional or posttranscriptional regulation and cellular recruitment. Our results demonstrate the complexity of gene regulation in the developing myocardium and show that cDNA microarrays can be used to monitor the evolution of the cardiac stress-inducible phenotype.

Animals↗
PubMed2000

A physiological model to predict xenobiotic concentration in fish.

A physiological model was developed to estimate fish body toxicant load based on information regarding the chemical exposure regime, fish body weight, lipid content and oxygen uptake. The general model was tested in which an oxygen database (OXYREF) was used to predict fish toxicant body burden. Based on the quantitative analysis, it was shown that the model was reliable and accurate in estimating fish body burden of a number of non-metabolized aquatic toxicants. This modified model possesses some functional reality which enables more realistic predictions, making it useful in the practice of aquatic environmental risk assessment.

Journal Article↗
PubMed2000

Relationship between toxicant transfer kinetic processes and fish oxygen consumption.

Three organic compounds of different hydrophobicity, 1,2,4,5-tetrachlorobenzene (TeCB), 3,4,5,6-tetrachloroguaiacol (TeCG) and 4,6-dichlorobenzenediol (DBD), were chosen as the test chemicals to carry out a series of investigations to look at the relationship between toxicant transfer and fish metabolic rate. A significant correlation was found between the toxicant uptake rate constant (k(1)) and fish oxygen consumption, regardless of fish size and species. This correlation was improved when fish toxicant body load was expressed on a percent body lipid basis. Similarly, there also existed a significant relationship between the toxicant depuration rate constant (k(2)) and fish oxygen uptake for a range of chemicals with different octanol/water partition coefficients (K(ow)).

Journal Article↗
PubMed2000

Platelet fibrinogen in the patients with idiopathic bleeding platelet disorder.

The changes of platelet fibrinogen in patients with obscure cutaneous mucosal bleeding and their relation with disease were evaluated. By using flow cytometry and Western blot, the platelet binding site of fibrinogen and the expression of platelet fibrinogen in 8 cases of obscure bleeding were detected. The results showed that platelet surface binding sites of fibrinogen were 65.38 +/- 3.62 in the resting state and 65.25 +/- 5.78 after activated by adenosine diphosphate, showing no significant difference as compared with control group (P > 0.05). The expression of platelet fibrinogen was obviously decreased in 4 patients and increased in one case as compared with control group. It was concluded that the binding sites of fibrinogen on the platelet surface were normal in the patients with idiopathic bleeding platelet disorder. The abnormal of platelet fibrinogen might be one of hemorrhagic reasons in partial patients.

Adult↗
PubMed2000

Characterization of demineralized bone matrix-induced osteogenesis in rat calvarial bone defects: III. Gene and protein expression.

Our previous studies of rat cranial defect repairs after the implantation of demineralized bone matrix (DBM) have demonstrated that healing occurs initially and principally by the direct induction and proliferation of osteoblasts derived principally from resident mesenchymal stem cells of the dura, and to a lesser extent by resident mesenchymal stem cells of the connective tissues beneath the skin flap. A small amount of cartilage is also synthesized after the direct process of ossification occurs. To further confirm the molecular phenotypes of the repair cells in rat cranial defects, the present study evaluated mRNA expression and synthesis of collagens I, II, and X and osteocalcin in the DBM-induced repair tissue by Northern blot analyses, autoradiography after in vivo (3)H-proline labeling of collagen, and immunohistochemistry. The results demonstrated that osteocalcin mRNA appeared in small amounts by day 4 and continued to increase over the experimental period. Much lesser quantities of collagen types II and X mRNAs appeared by day 6 and day 8, respectively. Collagen type I mRNA was present at all times examined but its expression significantly increased by day 5. Autoradiographic and immunohistochemical studies showed that type II collagen was not detected whereas type I collagen was synthesized on days 3-5. The data provide definitive molecular evidence confirming that the initial and by far the major pathway of cranial defects repair induced by implantation of DBM is by the direct induction of resident mesenchymal stem cells to osteoblasts and the direct formation of bone, which is spatially and temporarily distinct from the later formation of cartilage.

Animals↗
PubMed2000

A cost and performance evaluation of disposable and reusable biopsy forceps in GI endoscopy.

BACKGROUND: Biopsy forceps are widely used in gastrointestinal endoscopy, and yet few data exist on the usage and costs associated with disposable versus reusable forceps. METHODS: We prospectively measured the costs and operational performance of disposable and reusable forceps in 200 biopsy sessions; 100 sessions were performed using disposable forceps and 100 sessions were performed using reusable forceps. Total cost per use of the reusable forceps, including acquisition costs plus the costs of reprocessing per established guidelines, was determined. At the end of the study, the reusable forceps were disassembled to determine the cause of mechanical failures. RESULTS: The total cost per use of the disposable forceps was $38. For the reusable forceps, the acquisition cost per forceps was $415 and the total reprocessing cost was $16.56 +/- 0.07 per forceps. For 10, 15 and 20 uses, reusable forceps costs were $58.06, $44.23, and $37.31, respectively. Reusable forceps malfunction at 11 to 15 uses was 5%; at 16 to 20 uses was 25%; and at 21 to 25 uses reached 80% (p < 0.001). Dismantling of the reusable forceps at the end of the study demonstrated coiled sheath kinking, rust in the forceps closure mechanism, bent spikes, and biomaterial contamination. CONCLUSIONS: Up to 15 to 20 uses, disposable and reusable forceps costs were similar. If reusable forceps are used more than 20 times, then they are less expensive. However, in this range of uses, reusable biopsy forceps performance diminishes. With disposable biopsy forceps costing less than $40, cost differences between reusable and disposable forceps are minimal.

Biopsy↗
PubMed2000

Distinctness of spore and vegetative cellular fatty acid profiles of some aerobic endospore-forming bacilli.

A gas chromatographic analysis method was employed to determine the cellular fatty acid (CFA) profiles of spores and vegetative cells of some aerobic endospore-forming bacilli. The harvests of experimental strains were processed to obtain pure spores and acquire whole cell fatty acid methyl esters for the subsequent gas chromatographic analysis, and the corresponding vegetative cells were set as control. Evaluation of reproducibility of spore CFA components revealed that, provided under standardized experimental procedure, spore CFA composition was stable enough for research purposes. Fatty acids recovered in spores in greater quantities were saturated branched-chain acids containing 15 and 17 carbon atoms, similar to the vegetative cells. Commonly, the proportions of saturated branched-chain acids in spores were greater than in vegetative cells. The dendrograms obtained by cluster analysis provided some meaningful taxonomic information of the experimental strains. The fatty acids analysis of spores seems to be a promising supplementary tool for the chemotaxonomic research of aerobic endospore-forming bacilli.

Bacillaceae↗
PubMed2000

Autoimmunity to munc-18 in Rasmussen's encephalitis.

Rasmussen's encephalitis (RE) is a rare disease of the central nervous system characterized by severe epileptic seizures, progressive degeneration of a single cerebral hemisphere, and autoimmunity directed against glutamate receptor subunit, GluR3. We report here the identification of high-titer autoantibodies directed against munc-18 in the serum of a single patient with RE previously shown to have anti-GluR3 antibodies. Munc-18 is an intracellular protein residing in presynaptic terminals, which is required for secretion of neurotransmitters. These findings are consistent with the possibility of intermolecular epitope spreading between GluR3, a postsynaptic cell surface protein, and munc-18, a presynaptic intracellular protein. Immune attack on these two proteins, which participate at distinct steps of synaptic transmission, could act in an additive or synergistic manner to impair synaptic function and lead to seizures and neuronal death.

Amino Acid Sequence↗
PubMed2000

The mechanism of nitric oxide and/or superoxide cytotoxicity in endothelial cells.

We examined the mechanism of nitric oxide (NO) and/or superoxide (O2-)-induced cytotoxicity and the importance of thiols in endothelial cells by treating the cells with superoxide dismutase (SOD), catalase (CAT) and hemoglobin (Hb). Pyrogallol, a O2 generator and precursor of hydrogen peroxide (H2O2), had potent cytotoxic effects on the endothelial cells, but this effect was completely abolished by SOD/CAT. Hb, a NO scavenger, protected the endothelial cells from sodium nitroprusside-induced cytotoxicity. The cytotoxic effect of 3-morpholinosydnonimine (SIN-1), which is thought to form peroxynitrite (ONOO-) as a simultaneous O2- and NO generator, was completely blocked by SOD/CAT or Hb. On the other hand, pretreatment of endothelial cells with diethylmaleate, a glutathione depleter, aggravated the cytotoxicity induced by SIN-1, which was prevented by addition of exogenous glutathione and/or SOD/CAT. These data suggest that the cytotoxicity induced by NO, O2- and ONOO- can be blocked by glutathione, and that this is an important cellular protective mechanism against these reactive oxygen species.

Animals↗
PubMed2000

A new cembranolide from the soft coral Sinularia capillosa.

A new cembranolide, capillolide (1), and three known cembranolides were isolated from the soft coral Sinularia capillosa collected from the South China Sea. Their structures and the relative stereochemistry of 1 were deduced on the basis of spectroscopic methods.

Animals↗