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Y Gao

Publications and source records attributed to Y Gao.

At least 379 records · Page 21Linked to original sources
PubMed1996

[Effect of acute hypoxia on the change of hippocampal NE content and plasma cortisol level].

The effect of acute hypoxia on the changes of plasma cortisol level and hippocampus NE level of cat during inhalation of 21%, 10.4% or 7.9% O2 were investigated. It was found that both 10.4% and 7.9% O2 inhalation caused a gradual increase in plasma cortisol level reaching a plateau in 30-45 min time. While the contents of NE in VHIP and DHIP showed significant decrease 30 min after hypoxia. The degree of both these changes are not related to the hypoxic level of the inhaled O2. The results show that acute hypoxic stress would induce some increase in plasma cortisol level and some decrease in hippocampus NE content.

Animals↗
PubMed1996

[Cataract surgery in very long axial myopia].

OBJECTIVE: The incidence, refractive characters, operative results and the situations of intraocular lens (IOL) implantation in a series of eyes with very long axial length (> or = 27.00 mm) were analyzed. METHODS: According to the measurements of preoperative axial length and the degree of implanted IOL, the eyes with lengths of 27.00 mm or more selected from 1,000 eyes of consecutive senile cataract surgery were included in this group. The eyes requiring + 3.00D or more IOL were implanted with IOL. Simple extracapsular cataract extraction was performed on eyes requiring <+3.00D or negative lens. The postoperative follow-up was 20.0 +/- 8.5 months. RESULTS: There were 81 eyes in this group with a range of axial length of 27.00-34.71 mm and an average corneal curvature of 43.91 +/- 1.81D. The range of IOL power for these eyes was +11.30-11.57D (mean, +2.10 +/- 5.41D). The average axial length of 39 eyes with IOL implantation was 28.04 +/- 0.68 mm and their postoperative corrected visual acuities (PCVA) in 82.1% of eyes were 10/20 or more. The average length of 42 eyes without IOL implantation was 31.68 +/- 1.47 mm and the PCVAs in 42.9% of the eyes were 10/20 or more. CONCLUSIONS: The myopia with very long axial length is quite common in China. Its operative complications are not frequently seen. The cause of its poor PCVA is due to its pathologic changes in the fundus and the PCVA becomes worse as its axial length is increasing. An IOL with negative power is sometimes necessary for a myopic eye with very long axis.

Aged↗
PubMed1996

[An analysis of posterior capsular rupture in cataract surgery].

OBJECTIVE: To analyze the incidence, features and related factors of posterior capsular rupture (PCR) in extracapsular cataract extraction, the main intraoperative complication impairing the procedure of intraocular lens (IOL) implantation. METHODS: The PCR including zonular break and vitreous loss was recorded according to the stage of operative procedure in 757 eyes with senile cataract (the average age was 67.3 +/- 8.3 years). RESULTS: There were 51 eyes (6.7%) with PCR and 42 eyes (5.5%) of them accompanied with vitreous loss. The PCR in 17 eyes (33.3%) occurred during manual expression of the nucleus, 25 eyes (49.0%) in the course of aspiration of the cortex, and 9 eyes in the subsequent manipulations. Except the unexpected damage to the posterior capsule, the main factors were: smaller incision for the nucleus expression, lens dislocation during capsulotomy, small pupil in the course of cortex aspiration, high pressure from the posterior chamber and traction on capsular bag when removing anterior part of the cortex. CONCLUSION: Intraoperatively, the prevention of PCR and improvement of management ability are very important for the IOL I-stage implantation.

Aged↗
PubMed1996

[Expression of proliferating cell nuclear antigen and tumor suppressor gene P53 in mucoepidermoid carcinoma of salivary glands].

To explore the expression of proliferating cellnuclear antigen (PCNA) and tumor suppressor gene P53 product in mucoepidermoid carcinoma of the salivary glands, we studied 41 cases by immunohistochemical method. All of the cases were PCNA positive. The positive index, distribution pattern and cellular staining intensity for PCNA expression were correlated with carcinoma grade. P53 protein expression was found in 17 (41.5%) of the 41 cases; among them the expressions were weak in 9 cases. These results indicate that positive index, distribution pattern and cellular staining intensity of PCNA expression may be served as an indicator for evaluating the differentiating degree of the tumor.

Carcinoma, Mucoepidermoid↗
PubMed1996

[Water soluble contents of Chinese drug beimu, the bulbs of Fritillaria plants].

Based on platelet aggregation induced by platelet activating factor (PAF), the active fraction with inhibiting effect was screened from four species of Chinese drung Beimu, the bulbs of Fritillaria przewalskii, F. ussurienis, F. anhuiensis and F. thunbergii. According to the experimental results, the active water soluble fraction of F. ussuriensis was further studied. Two nucleosides, thymidine and adenosine were isolated. Platelet aggregation assay shows that adenosine is the chief aggregation inhibitor with 1% = 42 at 5 microns. It is suggested that nucleosides may be the other type of active constituent besides alkaloids in the Fritillaria plants.

Adenosine↗
PubMed1995

The XRCC4 gene encodes a novel protein involved in DNA double-strand break repair and V(D)J recombination.

The XR-1 Chinese hamster ovary cell line is impaired in DNA double-strand break repair (DSBR) and in ability to support V(D)J recombination of transiently introduced substrates. We now show that XR-1 cells support recombination-activating gene 1- and 2-mediated initiation of V(D)J recombination within a chromosomally integrated substrate, but are highly impaired in ability to complete the process by forming coding and recognition sequence joins. On this basis, we isolated a human cDNA sequence, termed XRCC4, whose expression confers normal V(D)J recombination ability and significant restoration of DSBR activity to XR-1, clearly demonstrating that this gene product is involved in both processes. The XRCC4 gene maps to the previously identified locus on human chromosome 5, is deleted in XR-1 cells, and encodes a ubiquitously expressed product unrelated to any described protein.

Amino Acid Sequence↗
PubMed1995

Site-directed mutagenesis of Lys600 in phosphoenolpyruvate carboxylase of Flaveria trinervia: its roles in catalytic and regulatory functions.

Phosphoenolpyruvate carboxylases from various organisms contain two conserved lysine residues. In the C4 dicot Flaveria trinervia, one of these residues is Lys600. Converting this Lys600 to Arg600 or Thr600 mainly increased the Km values and but had minimal effect on the Vmax. The Km for PEP, Mg2+ increased by up to 3-fold in Arg600 and Thr600 but the Km (HCO3-) increased 9-fold in Thr600, suggesting that Lys600 might be associated with bicarbonate-binding. This lysine was not obligatory for enzyme activity although the wild-type protein showed higher activity at physiological pH and was less inhibited by malate than the two mutants.

Amino Acid Sequence↗
PubMed1995

Characterization of a 95 kilodalton membrane glycoprotein associated with multi-drug resistance.

Over-expression of a 95-kDa membrane protein (P-95) has been reported previously in the multi-drug-resistant (MDR) breast cancer cell line MCF-7/AdrVp and the MDR small cell lung cancer line NCI-H1688. We have now developed anti-sera against gel-purified }-95 protein from each of these cell lines. Western blotting with each serum demonstrates a broad band at 95-kDa with detergent-solubilized membrane proteins from MCF-7/AdrVp and NCI-H1688 cells, which is barely detectable in membrane proteins from drug-sensitive parental MCF-7 cells. Each anti-serum cross-reacts with a 190-kDa membrane protein (P-190) in NCI-H1688 but not MCF-7/AdrVp cells. Immunoblotting and silver staining of NCI-H1688 membrane proteins separated by two-dimensional gel electrophoresis demonstrates that P-95 and P-190 run as broad streaks with low iso-electric points. Incubation of NCI-H1688 cells with tunicamycin or cleavage of carbohydrate residues of NCI-H1688 or MCF-7/AdrVp membrane proteins with PNGase F leads to the appearance of a sharp 35-kDa band reactive with anti-P-95 antisera. This 35-kDa protein has been isolated by two-dimensional gel electrophoresis. Neuraminidase digestion converts P-95 to a broad 65-kDa immunoreactive band, indicating the presence of terminal sialic acid residues. In conclusion, P-95 is an N-linked sialoglycoprotein with a 35-kDa polypeptide core.

Blotting, Western↗
PubMed1995

Sequential phosphorylation of adjacent serine residues on the N-terminal region of cardiac troponin-I: structure-activity implications of ordered phosphorylation.

We have used NMR spectroscopy to monitor the phosphorylation of a peptide corresponding to the N-terminal region of human cardiac troponin-I (residues 17-30), encompassing the two adjacent serine residues of the dual phosphorylation site. An ordered incorporation of phosphate catalysed by PKA was observed, with phosphorylation of Ser-24 preceding that of Ser-23. Diphosphorylation induced a conformational transition in this region, involving the specific association of the Arg-22 and Ser-24P side-chains, and maximally stabilised when both phosphoserines were in the di-anionic form. The results suggest that the second phosphorylation at Ser-23 of cardiac troponin-I is of particular significance in the mechanism by which adrenaline regulates the calcium sensitivity of the myofibrillar actomyosin Mg-ATPase.

Amino Acid Sequence↗
PubMed1995

Sendai virosomal infusion of an adeno-associated virus-derived construct containing neuropeptide Y into primary rat brain cultures.

A novel neuronal gene-delivery system was investigated in primary neuron-enriched cultures with respect to driving the expression of neuropeptide Y (NPY). This delivery system consists of an adeno-associated virus-derived (AAV) plasmid, pJDT95npy, encapsulated in reconstituted Sendai virosomes. pJDT95npy contains full length rat NPY cDNA inserted downstream from the P40 promoter in a cap-gene deleted AAV-derived construct. The rep-sequences under control of the P5 and P19 promoters are intact. Virosomally encapsulated pJDT95npy drove the expression of NPY mRNAs, predominantly by P40. Total cellular NPY immunoreactivity and release in the presence of depolarization increased following pJDT95npy-transfection. Neither empty virosomes nor virosomes containing pJDT95 affected NPY mRNA expression or immunoreactivity. This study demonstrates that an AAV-derived plasmid can drive exogenous gene expression in intact neurons after infusion by Sendai virosomes.

Adenoviridae↗
PubMed1995

Multimerization and transcriptional activation of the phosphoprotein (P) of vesicular stomatitis virus by casein kinase-II.

Casein kinase-II (CK-II) is a widely distributed protein kinase, which plays numerous roles in the regulation of transcription through modification of transacting transcription factors. Phosphorylation of vesicular stomatitis virus (VSV) P protein by CK-II was found to be both necessary and sufficient for transcriptional activation. Upon treatment of P by CK-II, activity was acquired faster (t1/2 = 3.7 min) than were total phosphates (t1/2 = 7.4 min). Stoichiometry was 2 mol phosphate/mol P, indicating activation by phosphorylation at either one or both of two independent sites. The sites were identified by substituting aspartate (D) residues at either S60 or T62, producing proteins that were partly active without phosphorylation, but were fully active at higher concentrations; CK-II added only a single phosphate group to each of these, and conferred full activity. P protein doubly substituted with D at S60 and T62 was fully active without phosphorylation, and was not a substrate for CK-II. Active P protein, whether CK-II treated or doubly substituted, was shown by gel filtration and crosslinking to exist as a discretely multimeric, probably tetrameric, structure. The singly substituted mutants were partly multimeric, becoming fully so after CK-II treatment. Phosphorylation by CK-II thus mediates the self-association of P into the multimeric, transcriptionally active form.

Amino Acid Sequence↗
PubMed1995

Agmatine: a novel endogenous vasodilator substance.

The purpose of the study was to investigate the effects of agmatine, an endogenous clonidine-displacing substance (CDS), on systemic hemodynamics in the anesthetized rat. Bolus intravenous (i.v.) injections of agmatine decreased systemic arterial pressure (SAP) and systemic vascular resistance in a dose-dependent manner. The development of acute tachyphylaxis to the systemic vasodepressor response to agmatine did not induce cross-tachyphylaxis to the systemic vasodepressor responses to bradykinin, isoproterenol and nitroglycerin. The present data demonstrate agmatine, as a CDS and agonist for imidazoline (I) receptors, possesses marked systemic vasodilator activity in the rat. The present data suggest that activation of I receptors may represent a novel mechanism of vasodilation in vivo.

Agmatine↗
PubMed1995

An isochromosome of the long arm of chromosome 18 in a patient with myelodysplastic syndrome with myelofibrosis.

A case of myelodysplastic syndrome (MDS) with myelofibrosis and i(18q) is reported. The patient, a 29-year-old Chinese man, was noted to be anemic over a 10-year period. Recently, his spleen became progressively massive and bone marrow aspirates yielded "dry taps" on several occasions. Hematologic investigation disclosed pancytopenia, numerous nucleated red cells, and slightly increased myeloblasts (8%) in the peripheral blood. Bone marrow aspirate and biopsy revealed hypercellular marrow, trilineage dysplasia, and significant reticulin fibrosis, but without collagen formation. Bone marrow karyotypic analysis with R-banding showed an isochromosome 18q as a sole abnormality in 20 of 24 metaphases analysed. The patient died of severe anemia and bleeding due to bone marrow failure. We believe that i(18q) and myelofibrosis may be related to his poor prognosis.

Adult↗
PubMed1995

BHV-1 glycoprotein 1 and recombinant interleukin 1 beta efficiently elicit mucosal IgA response.

The mucosal immune response to most soluble antigens administered directly to the mucosal system is low and requires a large amount of antigen and frequent vaccinations. In this study we tested whether immunizing cattle at a site which shares lymphatic drainage with the nasal mucosa could prime local mucosal immunity. We further tested whether recombinant bovine IL-1 beta (rBoIL-1 beta) could potentiate the induction of mucosal immunity. Animals were immunized subcutaneously at the base of the ear (s.e.) with recombinant bovine herpesvirus-1 (BHV-1) envelope glycoprotein I (gI) (35 micrograms animal-1) emulsified in incomplete Freund's adjuvant with or without rBoIL-1 beta (500 ng kg-1) followed by a second immunization 42 days later. Animals were challenged with virulent BHV-1 intranasally 42 days after the second immunization. Mucosal IgA from the nares was induced after only one immunization, and enhanced by boosting. rBoIL-1 beta treated animals had higher levels of BHV-1 specific nasal IgA (p < 0.01) and serum neutralizing antibody (p < 0.05). rBoIL-1 beta-treated animals also had increased numbers of surface IgA+ (p < 0.05) and IgG1+ (p < 0.001) B cells after in vitro antigen (gI) stimulation of peripheral blood lymphocytes suggesting that there was a greater expension of IgA+ and IgG1+ B cells in rBoIL-1 beta treated animals. When challenged with BHV-1, 3 of 4 animals in the gI+rBoIL-1 beta group were fully protected from viral replication in the nares, while only 1 of 4 animals receiving gI alone was protected.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The containment of toxic wastes: II. Metal movement in leachate and drainage at Parc lead-zinc mine, North Wales.

Nant Gwydyr, a tributary of the River Conwy in North Wales, has been affected by metal wastes, from a lead and zinc mine, Parc Mine, through contaminated mine drainage waters and episodal erosion of an unstable tailings heap. From 1954 when the mining operation was discontinued to 1978 when a reclamation programme aimed to stabilise the tailings was accomplished, 13 000 tonnes of metalliferous spoil, containing 43 tonne Pb, 104 tonne Zn, and 1 tonne Cd was eroded from the main tailings dam. Dispersal and redeposition during flood events caused extensive pollution of the agricultural land of the flood plain. Analysis of the present water quality of the Nant Gwydyr, 14 years after the stabilisation work, shows that although there has been a marked improvement and no particulate matter is released, the Nant Gwydyr is still a polluted stream. Under normal discharge conditions, it contributes approximately 1 tonne of Zn, 0.2 tonne of Pb and 0.05 tonne of Cd per year to the River Conwy. Most of this originates from water issuing from the mine adit which has been impossible to control. There is still, however, a major contribution by the leachate from the tailings heap, because the stabilisation method used does not prevent this. The control of pollution in mine drainage is discussed.

Journal Article↗