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Biomedical subjects

Y Guo

Publications and source records attributed to Y Guo.

At least 523 records · Page 29Linked to original sources
PubMed1996

[Effect of acupuncture on the restrained state of stomach after injecting TFP in zusanli point].

A model of the reducible movement of stomach in a big mouse was set up by injecting solution of 654-2. At first, the state of stomach movement was proved to be improved by acupuncture. After that, the activity of CaM in Zusanli point was lost by injecting TFP and effect of acupuncture on the stomach movement was studied. The result showed that the effect of acupuncture was abolished during manipulating the needles for 5 minutes. But retaining the needle for 25 minutes, the effect of acupuncture was recovered gradually. It indicates that the activity of Ca-CaM compounds may be of the key factor of acupuncture effect and one of the important links of the functional activity of meridians and collaterals.

Acupuncture Points↗
PubMed1996

Familial amyloid polyneuropathy--clinical report of a family.

This paper reports a familial amyloid polyneuropathy (FAP) family in China. This family being investigated had 69 members of five generations. From the third generation, there have been 16 patients. The age of onset was about 3 to 5 decades. The initial symptoms were autonomic nerve symptoms, such as impotence, dyspepsia and diarrhoea, associated with the sensory loss of lower extremities. As the disease progressed, the upper extremities and motor ability were also involved. The duration of disease course was about 8-10 years, most patients died of infection and cachexia. Sural biopsy in 3 patients had showed positive Congo red staining. From the clinical view, this FAP family is similar to FAP I found in Japan. The true classification, however, should be confirmed by further genetic analysis.

Adult↗
PubMed1996

[Extraovarian peritoneal serous papillary carcinoma: studies of clinical and pathological features].

OBJECTIVE: To study the clinicopathological features of extraovarian peritoneal serous papillary carcinoma (EPSPC). METHODS: The clinical pictures and pathological characteristics of 10 cases of EPSPC admitted to our hospital from 1980 through 1994 were studied retrospectively. Meanwhile, control studies were performed for 5 cases of ovarian serous papillary carcinoma and 4 cases of malignant peritoneal methothelioma. RESULTS: The ages of the 10 patients were between 44 and 77. The bilateral overies and fallopian tubes were all normal. The histomorphology as examined by photomicroscope and ultrastructural electromicroscope, the histochemistry determined by periodic acid-schiff (PAS) and Alcian blue stain and the immuno-histochemistry detected by carcinoembryonic antigen (CEA), AE1 and AE3 monoclonal antibody assays all revealed no difference between EPSPC and ovarian serous papillary carcinoma. The same is true for those between EPSPC and malignant methothelioma of peritonium except that the Alcian blue stain result would turned to be negative from positive after digesting with hyaluronidase and the micro-villi are longer for malignant peritoneal methothelioma as compared with EPSPC. CONCLUSIONS: The pathohistogenicity of EPSPC is not from ovaries but the methothelium of peritoneum, so called the secondary Müllarian system.

Aged↗
PubMed1996

[Mutations of p53 gene exons 5 to 8 in human ovarian cancer and its clinical significance].

OBJECTIVES: To detect p53 mutations in human ovarian cancer and to look for correlations between p53 mutation and clinicopathologic features. METHODS: Mutations in exons 5-8 of p53 gene in 41 patients with primary ovarian cancer were screened by polymerase chain reaction-single strand conformation polymorphism analysis with non-isotopic silver staining method. RESULTS: Mutations of p53 were found in 17 cases (41.5%); p53 mutation was not correlated with the age, the FIGO stage and the histologic type of the patients. However, it was associated with grade and lymph node metastasis in a univariate analysis. CONCLUSION: Mutations of p53 occur commonly in human ovarian cancer. p53 mutation is an early event in ovarian carcinogenesis and may serve as a genetic marker for early diagnosis and prognosis.

Adolescent↗
PubMed1996

[The detection and studies on the change of H+ concentration in the regular points of the rabbit suffering from arrhythmia induced by aconitine].

The past experiment showed that there was a specific change of H+ concentration in Neiguan (PC 6) of the rabbit suffering from arrhythmia induced by aconitine. When arrhythmia appeared, th ecocentration of H+ in Neiguan (PC 6) increased obviously. The authors found that it happened not only in the regular points but also along the course of the Heart Meridian and Pericardium Meridian in the furthe study and research. This may mean that on the course of the corresponding meridian there is a specific change of H+ concentration when the Zang-fu organs are in dysfunctional. But the mechanism and biological significance of the change of H+ concentration should remain to be further studied.

Aconitine↗
PubMed1996

[The changes of glucocorticoid receptor and beta-adrenoreceptor of lung tissues in SD rat asthma models and the effects of antiasthmatics on them].

OBJECTIVE: To observe the changes of glucocorticoid receptor (GR) and beta-adrenoreceptor (beta-AR) of lung tissue and the effects of oral procaterol, salbutamol and intraperitoneal (i.p.) or inhaled (i.h.) dexamethasone (Dex). METHOD: The GR or beta-AR were determined by using 3H-dexamethasone and 3H-Dihydroalprenolol as ligand respectively, in groups of rat asthma models at 1, 3, 7, 14th day and groups received antiasthmatics on the 7th day after daily consecutive challenges. RESULTS: The GR Bmax of asthma groups increased significantly after the first challenge, but decreased since the third day to a lower level than that of healthy control. The KD also decreased significantly since the third day. The beta-AR Bmax of asthma group gradually decreased to a significant low level on the 14th day. The Dex i.p. group had the lowest GR Bmax and the Dex i.h. group had the highest beta-AR Bmax among the treated. In the procaterol and salbutamol group, there had no decrease of GR Bmax compared with that of controls. CONCLUSIONS: The GR and beta-AR levels of lung tissues changed after daily challenges. The GC played a down-regulation role on GR and an up-regulation role on beta-AR in lung tissues. The Dex i.h. had more advantages than Dex i.p. in terms of GR and beta-AR regulations.

Adrenergic beta-Agonists↗
PubMed1996

[The application of otoacoustic emissions in paediatric hearing screening].

We conducted auditory test of 132 high risk infants by using both otoacoustic emissions (OAE) and auditory brainstem response (ABR) screening. The result showed that the passing rate was 88.3% (233/264 ears) for OAE and 92% (243/264 ears) for ABR. The sensitivity and specificity of OAE in comparison to ABR were 90.5% (19/21 ears) and 95% (230/243 ears) respectively. The mean test time was 3 min for OAE and 30 min for ABR. We therefore conclude that OAE is a highly sensitive, reliable and convenient method to be used for paediatric hearing screening.

Child, Preschool↗
PubMed1996

[Screening for the new formulation of 25% ascorbic acid injection and studies on its stability].

Two optimum new formulation of 25% ascobic Acid injection were selected by screening with the method of orthogomal design. To estimate the stability of these new formulations, samples were subjected to accelerated stability test at elevated temperatures. The rats of coloration and variation in the concentration of the new formulation under anaerobic degradation were studied. Experimental results indicate that the rule of coloration of ascorbic acid injection may be represented by the following regression equation T = T(o)-kt2 where To is the initial transmittance of the injection, T denotes the transmittance at time t, and k denotes the regression coefficient. The variation in the concentration of the two new formulations under amaerobic degradation was found to proceed in the pseudo-zero order reaction. The discoloration and content of ascorbic acid for two injections were predicted by accelerated stability test with the classical isothermal method and one-point method respectively. The discoloration shelf-life was about 39 months for R I and 36 months for R II, the content shelf-life about 40 months for R I and 38 months for R II respectively.

Animals↗
PubMed1995

Developmental expression of the immediate early gene EGR-1 mirrors the critical period in cat visual cortex.

Immediate early gene (IEG) expression in the central nervous system is thought to play a role in coupling extracellular stimulation with the transcriptional events responsible for long-term functional changes in neurons. The goal of the present study was to determine the postnatal developmental profile of EGR-1 protein (also termed zif268, Krox-24, NGFI-A) expression across the layers of cal visual cortex and relate it to the state of visual cortical development and plasticity. Using a polyclonal antibody, EGR-1 immunoreactivity was studied in animals of various postnatal ages (from 0.5 week to adult). In very young animals (0.5 weeks), EGR-1 positive cells were restricted to deep cortical layers (layer VI/Subplate). With the increasing age, EGR-1 immunoreactivity spread across layers of the visual cortex in an inside-outside manner, and by 5 weeks of age, EGR-1 protein was highly expressed in all layers. EGR-1 expression remained high until approximately 10 weeks of age and then gradually began to decline in layer IV with little change in supra- and infragranular layers. In adult animals, EGR-1 was located predominantly in the layers above and below layer IV. This pattern of EGR-1 expression in developing cat visual cortex has both temporal and laminar similarities with the development of visual cortical connectivity, with the development of orientation selective receptive field properties, and with the level of visual cortical plasticity, suggesting an involvement of EGR-1 expression in these processes.

Animals↗
PubMed1995

Signaling by a new anti-Thy 1 monoclonal antibody inhibits T cell proliferation and interferes with T-cell-mediated induction of costimulatory molecule B7-2.

Costimulatory activity on antigen-presenting cells is a critical determinant of the fate T cells when the T cell receptors are engaged by MHC:peptide complexes. Therefore, control of the expression of the costimulatory molecules regulates T cell responses. While several types of interactions between T cells and B cells up-regulate costimulatory molecules on antigen-presenting cell, no T cell surface molecules have been implicated in inhibiting the induction of the costimulatory molecules on B cells. Here we characterize a new anti-Thy1 mAb, 21F10, which inhibits T cell proliferation to selective stimuli. T cells stimulated by anti-CD3 together with anti-Thy1 mAb are anergic to further stimulation through the CD3, which suggests that the anti-Thy1 mAb interferes with the delivery of the costimulatory activity to T cells. Consistent with this notion, anti-Thy1 mAb 21F10 completely inhibits the induction of B7-2 on B cells. Induction of several T cell surface molecules such as CD69 and CD40 ligand was largely unaffected. As this inhibition requires a bivalent anti-Thy1 mAb and does not require binding of more than 50% of Thy1 molecules on T cell surface, we suggest that Thy1 may mediate a negative signaling pathway which inhibits the T-cell-mediated induction of costimulatory activity, including expression of co-stimulatory molecule B7-2.

Animals↗
PubMed1995

Alternative splicing of PSP94 (prostatic secretory protein of 94 amino acids) mRNA in prostate tissue.

While performing reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of total mRNA from prostate cancer specimens, two forms of PSP94 cDNA were detected. RT-PCR products were analysed by Southern blotting and probing with exon-specific oligonucleotides. In the short form of PSP94 mRNA, designated as PSP57, exon III was found to be deleted. The two mRNA forms were confirmed by cloning and sequencing of the RT-PCR products and were found to result from alternative splicing. The alternatively spliced form, PSP57, was characterized by sequence analysis. PSP94 and PSP57 possess identical exons I and II, including identical secretion signal peptide and the 5' untranslated sequences. PSP57 has a frame-shifted exon IV and encodes a putative 57 amino acid protein with a novel, highly basic C-terminus of 41 amino acids. PSP57 mRNA was detected in other urogenital tissues (kidney, bladder) and in most tumor cell lines tested, but was not detectable in other tissues such as breast and lung. In prostate tumor cell lines, PSP57 mRNA was aberrantly spliced and localized in the nuclear fraction of the cell. Our results suggest the possible existence of a novel PSP protein that originates from alternative splicing of PSP94 mRNA in urogenital tissues.

Aged↗
PubMed1995

Identification by targeted differential display of an immediate early gene encoding a putative serine/threonine kinase.

Fibroblast growth factor (FGF)-1 mitogenic signal transduction is mediated in part by gene products that are specifically expressed in response to cell surface receptor binding and activation. We have used a targeted differential display method to identify FGF-1-inducible genes in murine NIH 3T3 fibroblasts. Here we report that one of these genes is predicted to encode a novel serine/threonine-specific protein kinase. This putative kinase has been named Fnk, for FGF-inducible kinase. The deduced Fnk amino acid sequence has 49, 36, 33, 32, and 22% overall identity to mouse serum-inducible kinase (Snk), mouse polo-like kinase (Plk), Drosophila polo, Saccharomyces Cdc5, and mouse Snk/Plk-akin kinase (Sak), respectively. These proteins are all members of the polo subfamily of structurally related serine/threonine kinases. The Plk, polo, Cdc5, and Sak kinases are required for cell division. FGF-1 induction of Fnk mRNA expression is first detected at 30 min after mitogen addition, reflects transcriptional activation, and does not require de novo protein synthesis. FGF-2, platelet-derived growth factor-BB, calf serum, or phorbol myristate acetate treatment of quiescent cells also induces fnk gene expression. Fnk mRNA is expressed in vivo in a tissue-specific manner, with relatively high levels detected in newborn and adult mouse skin. These results indicate that Fnk may be a transiently expressed protein kinase involved in the early signaling events required for growth factor-stimulated cell cycle progression.

3T3 Cells↗
PubMed1995

Mutational analysis and an alternatively spliced product of B7 defines its CD28/CTLA4-binding site on immunoglobulin C-like domain.

Costimulatory molecules B7 and B7-2 interact with T cell surface receptors CD28/CTLA4 and deliver a costimulatory signal essential for T cell growth. However, the structure basis of this interaction is not known. B7 and B7-2 are members of immunoglobulin (Ig) superfamily and their extracellular portion consists of an IgV- and IgC-like domain. Here we report that a naturally occurring, alternatively spliced form of B7 reveals that exon 3-encoded IgC domain is essential for CD28/CTLA4 binding. Mutational analysis of B7 demonstrates a critical role of several amino acids around loops between strands B and C and D and E, for binding CTLA4/CD28. These amino acids are clustered to form a single binding site centered at 201Y. A comparison of the effects of mutations on the binding of CD28 and CTLA4 reveals that CD28 and CTLA4 binds to the same site on B7. These results have important implications on the role of CTLA4 and CD28 in T cell costimulation. The structure of the CD28/CTLA4-binding site also provides valuable information for immune intervention targeted at the B7/B7-2-CD28/CTLA4 interactions.

Abatacept↗
PubMed1995

The catalytic role of aspartic acid-92 in a human dual-specific protein-tyrosine-phosphatase.

The mechanism of catalysis for the human dual-specific (vaccinia H1-related) protein-tyrosine-phosphatase was investigated. The pH dependence of the kcat value is bell-shaped when p-nitrophenyl phosphate was employed as a model substrate. The kcat/Km pH profile rises with a slope of 2 and decreases with a slope of -1, indicating that two groups must be unprotonated and one group must be protonated for activity. An amino acid residue with an apparent pKa value of 5.5 +/- 0.2 must be unprotonated and a residue with a pKa value of 5.7 must be unprotonated for activity. The pKa value of the catalytic cysteine-124 (C124) was 5.6 +/- 0.1. The aspartic acid-92-asparagine (D92N) mutant enzyme was 100-fold less active than the native enzyme and exhibited the loss of the basic limb in the pH profiles, suggesting that in the native enzyme D92 must be protonated for activity. The D92 residue is conserved throughout the entire family of dual-specific phosphatases. Mutants glutamic acid-6-glutamine, glutamic acid-32-glutamine, aspartic acid-14-asparagine, and aspartic acid-110-asparagine had less than a 2-fold effect on the kinetic parameters when compared to native enzyme. Based upon the lack of a "burst" in rapid reaction kinetics, formation of the intermediate is rate-limiting with both native and D92N mutant enzymes. In agreement with rate-limiting formation of the intermediate, the pKa value of 5.5 for the group which must be unprotonated for activity was assigned to C124.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

Analysis of underivatized amino acids by capillary electrophoresis using constant potential amperometric detection.

A mixture of native (underivatized) amino acids is separated by capillary electrophoresis under alkaline conditions (pH approximately 12) and amperometrically detected with a copper-disk microelectrode. A simple design facilitates capillary-electrode alignment without the need for micropositioning equipment. The limits of detection for the amino acids are in the low microM concentration range, and the signal response is linear over 2-3 orders of magnitude. This procedure is applied to analyze the amino acid hydrolysis products from cytochrome c.

Amino Acids↗
PubMed1995

Elevated plasma chitotriosidase activity in various lysosomal storage disorders.

Recently a striking elevation of the activity of chitotriosidase, an endo beta-glucosaminidase distinct from lysozyme, was found in plasma from patients with Gaucher type I disease (McKusick 230800). Plasma chitotriosidase originates from activated macrophages and this elevation is secondary to the basic defect in Gaucher disease. To investigate the specificity of this phenomenon, we have investigated 24 different lysosomal storage diseases. In 11 different diseases increased chitotriosidase activity in plasma was found (in 28% of the patients). None of these diseases showed elevations as high as in Gaucher disease. Chitotriosidase was not significantly elevated in plasma from 20 different non-lysosomal enzymopathies or in plasma from patients with infectious diseases associated with hepatomegaly. The results show that marked elevation of chitotriosidase activity in plasma appears to be specific for Gaucher disease. The data further suggest that elevated levels of chitotriosidase activity in plasma from patients with unexplained diseases may be indicative for a lysosomal disorder.

Adult↗
PubMed1995

Natural, high-mannose glycoproteins inhibit ROS binding and ingestion by RPE cell cultures.

Previous studies have suggested that a mannose receptor mediates the phagocytic uptake of effete rod outer segments by retinal pigment epithelial cells. In the present study, the effect of adding a soluble ligand for the mannose receptor, horseradish peroxidase, was examined. Cultured retinal pigment epithelial cells from Long Evans rats were preincubated with various concentrations of horseradish peroxidase for 20 min followed by a challenge of FITC-labeled bovine rod outer segments for 3 h. Both counts of total rod outer segments (bound and ingested) and ingested rod outer segments were determined. Rod outer segment uptake was reduced, in a concentration-dependent fashion, by an average of 60% of control values when horseradish peroxidase was added to retinal pigment epithelial cultures. Similarly, total rod outer segment values were reduced to 50% of controls in the presence of at least a 10 micrograms ml-1 horseradish peroxidase concentration. Horseradish peroxidase inhibition of retinal pigment epithelial phagocytic capacity was reversible. Other high mannose glycoproteins, such as invertase, beta-glucoronidase, and ovalbumin, were equally effective in preventing rod outer segment ingestion by retinal pigment epithelial cells. These data further support the hypothesis that a mannose receptor on the retinal pigment epithelial apical surface facilitates phagocytosis of rod outer segments.

Animals↗