Search PubMed⌕ Search

Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 973 records · Page 54Linked to original sources
PubMed1997

[Experimental and clinical study on the blood supply of the subdermal vascular network island flap].

A comparison study on the blood supply of the buttock subdermal vascular network island skin flap and the conventional buttock island flap was undertaken in pigs. The former was created by thinning the distal half of the conventional buttock island flap, preserving the subdermal vascular network. Evaluation was made by measurement of skin temperature, laser Doppler, fluorescence stain, ink perfusion, microangiography and transparent specimen technique. It was found that the blood supply of the subdermal vascular network island skin flap was much lower than that of the conventional island flap. The reason was thought to be the change in the blood supply after the conventional island flap was thinned. The subdermal vascular network island skin flap was composed of the axial pattern and the random pattern. Fifteen subdermal vascular network island skin flaps have been successfully transferred with vessel anastomosis in 15 patients. The average area of the thinned distal part was 49% of the flap, with the maximum of 60%.

Animals↗
PubMed1997

[Distribution of obese protein in the mouse tissue].

In the present study, the contents of obese protein of tissue from liver, brain, abdominal wall fat, skeletal muscle and the contents of plasma OP of mice were measured with radio immunoassay. The results showed that the contents of OP were much higher in the brain than that in the abdominal wall fat tissue (P < 0.01). The liver and the skeletal muscle tissue did not show the presence of OP. The contents of OP of abdominal wall fat tissue were lower in the female than that in the male mice (P < 0.05).

Abdominal Muscles↗
PubMed1997

[Elastic light scattering of blood cell counting and classification].

In this paper we discuss the elastic light scattering techniques used in blood cell counting and classification and expound the principles of elastic light scattering techniques and four theoretical scattering models of blood cell and the applicable areas. Also we analyze their application in recent years and point out the problems to be solved.

Blood Cell Count↗
PubMed1997

[Effects of vasoactive intestinal peptide, alpha-chymotrypsin, pancreozymin, lipase, phospholipase A2 and collagenase on the viscoelasticity properties of red blood cell suspension].

Using Low Shear-30 Rheometer, we studied the effects of vasoactive intestinal peptide, alpha-chymotrypsin, pancreozymin, lipase, phospholipase A2 and collagenase on the viscoelasticity properties of RBC suspension. The result showed that these drugs could increase the values of eta 0.512 and A. I. It suggests that these drugs could increase the degree of RBC aggregation. Among the drugs and concentrations, there is no significant difference.

Blood Viscosity↗
PubMed1997

[Changes of NMDA receptor gene expression in infection brain injury induced by Bordetella pertussis in rats].

N-methyl-D-aspartate receptors (NMDAR) in cerebral cortexes of rat brain injury induced by Bordetella pertussis (Bp) were measured by methods of Northern blot analysis and [3H] MK-801 radioligand-receptor binding to study changes and effects of NMDAR1 of gene expression in the infection brain injury. The affinity (Kd) of NMDAR in Bp group was significantly decreased [30.5 +/- 3.0 nmol.L-1 (Bp), 43.1 +/- 4.2 nmol.L-1 (NS), P < 0.05], but expression of NMDAR1 mRNA and binding site density (Bmax) of NMDAR observed no significant differences between the experimental and the control group (P > 0.05), respectively. The results suggest that NMDAR1 was activated with high affinity functionally, but no changes in binding site density and transcriptional expression of NMDAR1 occured in the infection brain injury.

Animals↗
PubMed1997

[A clinicopathological immunohistochemical and cytomorphometric study on midline T cell lymphoma].

One hundred and twenty-two cases of midline malignant reticulosis (MMR) were studied. A series of antibodies including anti-LCA, UCHL-1, L26, CD45R, and anti-lysozyme were used on paraffin sections by ABC and PAP methods. The results were as follows: 112 cases exhibiting T-cell origin, 4 cases showing B-cell origin, and 6 cases being of uncertain lineage. This result is in accordance with the point of view that most of MMR are T cell lymphoma. Two histological types were classified: sarcomatoid type and granulomatoid type. By using image analyzer, the sarcomatoid type was subdivided into small, medium and large cell types. Sixty-two cases with follow-up data were collected for clinicopathologic analysis. One-year and five-year survival rates in cases with different histologic types were compared and statistically analysed. The results showed that the prognosis was closely related to the histological type.

Adolescent↗
PubMed1997

[Electromyogram (EMG) and muscle biopsy in patients with chronic spinal muscular atrophy].

The clinicopathological changes were investigated by electromyogram (EMG) and muscle biopsy in 30 cases of chronic spinal muscular atrophy. The results showed that the denervating changes were demonstrated in EMG in all patients but two. The light microscope discovered manifestation of neurogenic atrophy, and the electron microscope revealed a reduction of myofibrils, thickening and wavy appearance of Z-lines and dilation of mitochondria and endoplasmic reticula.

Adolescent↗
PubMed1997

[Effect of monoclonal antibody against human tissue factor pathway inhibitor on plasma coagulation time].

The purpose of this study was to evaluate the influences of the monoclonal antibody against human tissue factor pathway inhibitor (TFPI), McAb4F8, on prothrombin time (PT) and activated partial thromboplatin time (APTT). The results showed that PT and APTT were prolonged by exogenous TFPI. Dilute thromboplastin coagulation time was shortened with a dose-dependent manner by McAb4f8. Low molecular weight heparin (LMWH) prolonged significantly PT and APTT, and this effect ws weakened by an antibody against human AT III. McAb4F8 was also proved to shorten dilute thromboplastin coagulation time of factor IX deficient plasma. These results indicated that the tissue factor pathway plays an important role not only in physiological coagulation but also in hemorrhage of hemophilia.

Animals↗
PubMed1997

[Delayed brain injury induced by Bordetella pertussis in rats].

To induced new model of delayed infection brain injury, we divided randomly 40 adult male Sprague-Dawley rats into four groups: bordetella pertussis (BP) groups, and normal sailine (NS) groups in 4 h (n = 10) and 24 h (n = 10), respectively, injected BP at 0.2 ml.kg-1 which contained the bacilli in 10.8 x 10(9).ml-1 into the rat left internal carotid artery of BP groups, and injected at the equal volume as control in the same way into NS groups. The water content (WC), Evans blue content (EB), cations of sodium, potassium, calcium in the brain tissues were measured and the morphologic changes in the hippocampal CA1 were detected by electron microscopy. These results were shown as follows: the left hemisphere of BP group in 4 h was characterized by the brain edema which predominated in swollen, necrotic astroglial cells, endothelial cells, and insignificant increase of contents of sodium, calcium and decrease of potassium; BP group in 24 h was characterized by dark cells, the brain edema also existed in astroglial cells. These results indicate that a delayed infection brain injury model is performed successfully by injection with BP into the left internal carotid artery of rats. The model is characterized by the features of delayed neuronal death and mixed type brain edema.

Animals↗
PubMed1996

Age-dependent effects of glutamate toxicity in the hippocampus.

While prolonged seizures can cause brain damage at any age, the extent of brain damage following prolonged seizures is highly age-dependent. Seizures in the immature brain are followed by far less histological damage than seizures of similar duration and intensity in mature animals. The reasons for this age-related phenomenon are unclear. Seizure-induced cell death may be due to the neurotoxic effects of excessive glutamate release, we tested the hypothesis that the immature brain is less vulnerable to glutamate-induced neurotoxicity than the mature brain. We administered equal amounts of glutamate (0.5 mumol in 1.0 microliter) unilaterally into the CA1 subfield of the hippocampus of rats at postnatal (P) days 10, 20, 30, and 60. Equal volumes of saline were injected in the contralateral hippocampus. Rats were killed 7 days later and their brains were examined for hippocampal cell loss. The size of the resultant hippocampal lesion was highly age-dependent. Minimal cell loss was noted in the P10 rats, lesions in the P20 rats were smaller than those at P30 and P60, which were similar in extent. This study demonstrates that the extent of glutamate neurotoxicity in the hippocampus is highly age-dependent, with immature hippocampi relatively resistant to glutamate-induced cell death.

Aging↗
PubMed1996

Isolation and characterization of a tobacco mosaic virus-inducible myb oncogene homolog from tobacco.

Salicylic acid (SA) plays an important role in signaling the activation of plant defense responses against pathogen attack including induction of pathogenesis-related (PR) proteins. To gain further insight into the SA-mediated signal transduction pathway, we have isolated and characterized a tobacco mosaic virus (TMV)-inducible myb oncogene homolog (myb1) from tobacco. The myb1 gene was induced upon TMV infection during both the hypersensitive response and development of systemic acquired resistance in the resistant tobacco cultivar following the rise of endogenous SA, but was not activated in the susceptible cultivar that fails to accumulate SA. The myb1 gene was also induced by incompatible bacterial pathogen Pseudomonas syringae pv. syringae during the hypersensitive response. Exogenous SA treatment rapidly (within 15 min) activated the expression of myb1 in both resistant and susceptible tobacco cultivars with the subsequent induction of PR genes occurring several hours later. Biologically active analogs of SA and 2,6-dichloroisonicotinic acid (a synthetic functional analog of SA), which induce PR genes and enhanced resistance, also activated the myb1 gene. In contrast, biologically inactive analogs were poor inducers of myb1 gene expression. Furthermore, the recombinant Myb1 protein was shown to specifically bind to a Myb-binding consensus sequence found in the promoter of the PR-1a gene. Taken together, these results suggest that the tobacco myb1 gene encodes a signaling component down-stream of SA that may participate in transcriptional activation of PR genes and plant disease resistance.

Amino Acid Sequence↗
PubMed1996

A method for the large scale isolation of high transformation efficiency fungal genomic DNA.

A procedure for isolation of genomic DNA from the zygomycete Cunninghamella elegans and other filamentous fungi and yeasts is reported. This procedure involves disruption of cells by grinding using dry ice, removal of polysaccharides using cetyltrimethylammonium bromide and by phenol extractions, and precipitation of DNA with isopropanol at room temperature. The isolation method produced large scale (approximate 1 mg DNA/5 g wet cells) and highly purified high molecular mass DNA. Sau3AI partially digested DNA showed high transformation efficiency (> 10(6)/100 ng DNA) when ligated to ZAP-express lambda vector.

Basidiomycota↗
PubMed1996

Transforming growth factor-beta1 inhibits human keratinocyte proliferation by upregulation of a receptor-type tyrosine phosphatase R-PTP-kappa gene expression.

We studied regulation of a receptor-type tyrosine phosphatase R-PTP-kappa gene expression in a human keratinocyte cell line, HaCaT. Addition of TGF-beta 1 to the HaCaT cells markedly induced the expression of R-PTP-kappa mRNA in a time- and dose-dependent manner. The induction of R-PTP-kappa mRNA expression was observed at a dose as low as 0.02 ng/ml TGF-beta1 and reached a peak at 2 ng/ml TGF-beta 1 after 6 h treatment. The TGF-beta 1-induced R-PTP-kappa mRNA expression was suppressed by sodium orthovanadate, a tyrosine phosphatase inhibitor, and H7, a serine/threonine kinase inhibitor, but not by genistein, a tyrosine kinase inhibitor. In addition, the inducing effect is not dependent on de novo protein synthesis. Taken together, these results suggest that TGF-beta 1 inhibits the human keratinocyte proliferation in vitro, possibly through induction of R-PTP-kappa gene expression.

Cell Division↗
PubMed1996

Genomic organization of mouse Dishevelled genes.

We report the isolation and characterization of two new genomic loci corresponding to the mouse Dishevelled (Dvl) genes Dvl2 and Dvl3. The Dvl genes are homologs of the Drosophila dsh segment polarity gene, and are involved in the Wnt/wingless signal transduction pathway. Dvl2 and Dvl3 genomic clones were isolated from a mouse 129 strain gamma FIXII genomic library and have identical exon/intron organization to Dvl1. All three Dishevelled genes span 15 exons and 14 introns and have a number of conserved splice junction sites.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Formation of mammalian metabolites of cyclobenzaprine by the fungus, Cunninghamella elegans.

The fungus, Cunninghamella elegans, was used as a microbial model of mammalian drug metabolism to biotransform a tricyclic antidepressant, cyclobenzaprine. Seventy-five percent of this drug at a concentration of 1 mM was metabolized within 72 h by C. elegans grown on Sabouraud dextrose broth. Milligram amounts of fungal metabolites were isolated by reversed-phase high performance liquid chromatography (HPLC) and their structures were characterized by 1H NMR spectroscopy, mass spectrometry, and UV spectroscopy analyses. The major fungal metabolites of cyclobenzaprine were 2-hydroxycyclobenzaprine (59%), N-desmethylcyclobenzaprine (21%), cyclobenzaprine trans-10,11-dihydrodiol (5%), N-desmethyl-2-hydroxy-cyclobenzaprine (3%), 3-hydroxycyclobenzaprine (3%), and cyclobenzaprine N-oxide (1%). These fungal metabolites were used as standards to investigate the metabolism of cyclobenzaprine by rat liver microsomes. Rat liver microsomes also biotransformed cyclobenzaprine to produce similar metabolites as the fungus. The isotope labeling of 2-hydroxycyclobenzaprine by 18O2 and the trans-configuration of the dihydrodiol suggested that these reactions were catalyzed by cytochrome P-450 monooxygenases in C. elegans. These results also demonstrated that the fungal biotransformation system could be used to predict and synthesize the mammalian drug metabolites.

Amitriptyline↗
PubMed1996

Human cytomegalovirus inhibits antigen presentation by a sequential multistep process.

The human cytomegalovirus (HCMV) genomic unique short (US) region encodes a family of homologous genes essential for the inhibition of major histocompatibility complex (MHC) class I-mediated antigen presentation during viral infection. Here we show that US3, the only immediate early (IE) gene within the US region, encodes an endoplasmic reticulum-resident glycoprotein that prevents intracellular transport of MHC class I molecules. In contrast to the rapid degradation of newly synthesized MHC class I heavy chains mediated by the early gene product US11, we found that US3 retains stable MHC class I heterodimers in the endoplasmic reticulum that are loaded with peptides while retained in the ER. Consistent with the expression pattern of US3 and US11, MHC class I molecules are retained but not degraded during the IE period of infection. Our data identify the first nonregulatory role of an IE protein of HCMV and suggest that HCMV uses different T-cell escape strategies at different times during the infectious cycle.

Amino Acid Sequence↗
PubMed1996

CD40 ligand-dependent T cell activation: requirement of B7-CD28 signaling through CD40.

The role of CD40 ligand (CD40L) in the primary activation of T cells is not clear. The cellular and humoral immune responses to adenoviral vectors in a murine model of liver-directed gene transfer were studied to define the mechanisms responsible for CD40L-dependent T cell priming. CD40L-deficient mice did not develop effective cytotoxic T cells to transduced hepatocytes, and T cell-dependent B cell responses were absent. Full reconstitution of cellular and humoral immunity was achieved in CD40L-deficient mice by administration of an activating antibody to CD40 that increased expression of B7.2 on spleen cells. Wild-type mice could be made nonresponsive to vector by administration of antibodies to B7. Thus, CD40L-dependent activation of T cells occurs through signaling of CD40 in the antigen-presenting cell to enhance requisite costimulatory pathways that include B7.

Adenoviridae↗