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Biomedical subjects

Q Gu

Publications and source records attributed to Q Gu.

At least 55 records · Page 3Linked to original sources
PubMed1999

Selective cloning of cell surface proteins involved in organ development: epithelial glycoprotein is involved in normal epithelial differentiation.

Coordinating the activities of neighboring cells during development in multicellular organisms requires complex cellular interactions involving secreted, cell surface, and extracellular matrix components. Although most cloning efforts have concentrated on secreted molecules, recent work has emphasized the importance of membrane-bound molecules during development. To identify developmental genes, we raised antibodies to normal embryonic pancreatic epithelial cell surface proteins. These antibodies were characterized and used to clone the genes coding for the proteins by a panning strategy. Using this approach, we cloned the rat homologue of the mouse epithelial glycoprotein (EGP). Our immunohistochemistry data, describing the expression of EGP during rat development, as well as our in vitro data, looking at the effect of the anti-EGP antibody and the extracellular domain of EGP on embryonic pancreatic epithelial cell number and volume, strongly suggest a role for EGP during pancreatic development.

Amino Acid Sequence↗
PubMed1999

Rapid action of 17beta-estradiol on kainate-induced currents in hippocampal neurons lacking intracellular estrogen receptors.

17Beta-estradiol can potentiate kainate-induced currents in isolated hippocampal CA1 neurons. The action of estrogen was rapid in onset, steroid and stereospecific, and reversible. The potentiation could be mimicked by 8-bromo-cAMP, an activator of protein kinase A. As the hippocampus expresses both isoforms of the intracellular estrogen receptor (ER alpha and ER beta), the role of ERs in the rapid action of 17beta-estradiol remains elusive. Here we report that the rapid action of 17beta-estradiol is independent from the classical ER activation in the modulation of membrane excitability. Under whole cell voltage clamp recording configuration, 17beta-estradiol-induced potentiation was observed in both wild-type and the ER alpha gene knockout mice. The perfusion or incubation of ICI 182,780, which blocks both ER alpha and ER beta, did not affect estrogen potentiation in either group. Further study showed that adenosine 3',5'-cyclic-monophosphothioate Rp-isomer, a specific inhibitor of protein kinase A, completely blocked the potentiation observed with the application of 17beta-estradiol in ER alpha gene knockout mice. Our results provide evidence that a distinct estrogen-binding site exists, which appears to be coupled to alpha-amino-3-hydroxyl-5-methyl-4-isoxazole proprionic acid/kainate receptors by a cAMP-dependent phosphorylation process.

Animals↗
PubMed1999

Intravenous infusion ascitic fluid during hemodialysis: a study of 108 treatments in 13 uremic cases.

Nephrogenic ascites is a clinical diagnosis defined as persistent ascites in an uremic patient without evidence for a causative underlying disease. It imperils the patient's life with intradialytic hypotension, however there is no effective therapy other than renal transplantation so far. In 13 cases, 108 treatments with i.v. ascites infusion were performed with hemofilter alone or combined with plasmafilter during hemodialysis over past 7-years. The ascitic fluid was filtrated and dialyzed before it was intravenously infused into the blood compartment of the hemofilter. There were a mean of 8.38 treatments per patient in a period of 56 days and 3,275.9 +/- 1,359.5 ml of ascitic fluid were removed per treatment. The patients' appetite and physical ability were considerably improved and the intradialytic hypotensions disappeared immediately following the initiation of ascitic fluid infusions. In this study, one patient was transplanted successfully. The longest interval without ascitic fluid infusion was 127 days. Main side effect was light pyrogenic reaction, which was presented in 12.96% of the total treatments. It is concluded that this method permits to continue hemodialysis, improves the nutritional condition and prolongs the lifespan by conserving and reusing the ascites protein.

Adult↗
PubMed1999

[Collagen expression of intra-acinar pulmonary arteries and right ventricle and intervention of Radix Astragali in rats with hypoxic pulmonary hypertension].

OBJECTIVE: To investigate the collagen expression effect of intra-acinar pulmonary arteries and the right ventricle and to observe the intervention effect of Radix Astragali in rats with hypoxic pulmonary hypertension. METHODS: Wistar male rats were divided into three groups: hypoxia group, which was fed in hypoxic environment (oxygen concentration was 9%-12%) under normal atmospheric pressure for three weeks (12 hours every day); intervention group, which was abdomenly injected with Radix Astragali and fed in the same environment as hypoxia group; and control group, which was fed in normal environment. Pulmonary artery pressure and cardiac output of the right ventricle were measured with catheterization and Fick's method. Protein expression of collagen in intra-acinar pulmonary arteries was assessed with histopathologic method. mRNA expressions of collagen in the right ventricle, and endothelin-1 and nitric oxide synthase in lung tissue were evaluated by RT-PCR technique. RESULTS: Compared with those in control group, pulmonary artery pressure and protein expression of collagen in intra-acinar pulmonary arteries and mRNA expression of type I collagen in the right ventricle and endothelin-1 in lung tissue were obviously increased in hypoxia group (mean pulmonary artery pressure: (24.8 +/- 3.6) mm Hg vs (18.8 +/- 1.7) mm Hg, P < 0.01; protein expression of collagen: (20.4 +/- 4.5) AU vs (3.4 +/- 1.1) AU (P < 0.01), but mRNA expression of nitric oxide synthase in lung tissue was declined. Compared with the data obtained in hypoxia group, cardiac output and mRNA expression of nitric oxide synthase in lung tissue were raised in intervention group (cardiac output: [(141 +/- 20) ml/min vs (118 +/- 40) ml/min, P < 0.01], but protein expression of collagen in intra-acinar pulmonary arteries and mRNA expression of type I collagen in the right ventricle and endothelin-1 in lung tissue were markedly decreased (protein expression of collagen: [(5.6 +/- 1.2) AU vs (20.4 +/- 4.5) AU, P < 0.001]. CONCLUSION: Changes of collagen expression in intra-acinar pulmonary arteries and right ventricle are one of the most important features in remodeling of pulmonary arteries and right ventricle in hypoxic pulmonary hypertension. Radix Astragali can partly inhibit the remodeling of pulmonary arteries and right ventricle, and regulate mRNA expression of endothelin-1, nitric oxide synthase, and collagen, thus contributing to the treatment of hypoxic pulmonary hypertension.

Animals↗
PubMed1999

[The diagnostic significance of antineutrophil cytoplasmic antibodies in ulcerative colitis].

OBJECTIVE: To inquire into the diagnostic significance of antineutrophil cytoplasmic antibodies (ANCA) in ulcerative colitis (UC). METHODS: Serum ANCA from 58 UC patients, 43 non-UC patients and 58 healthy donors were detected with indirect immunofluorescence (IIF), enzyme linked immunosorbent assay (ELISA)and Western blot. RESULTS: The sensitivity and specificity of the presence of ANCA in the diagnosis of UC were 37.93% and 100% respectively. In the group of UC, patients with mild, moderate and severe clinical manifestations had positive ANCA rates of 17.65%, 41.67% and 52.94% respectively. The occurrence rates of mucosal vasculitis and grade III-V mucosal inflammation were 78.95% and 78.95% respectively in ANCA-positive group, but 37.04% and 44.44% in ANCA-negative group. The levels of the binding of the five kinds of ANCA antigens i.e. myeloperoxidase (MPO), bactericidal/permeability increasing protein (BPI), lactoferrin (LF), cathepsin G (CG) and proteinase-3 (PR-3) with the serum of UC patients were 13.99%, 13.79%, 10.34% 10.34% and 8.62% respectively. Specific protein strips were observed in 48.28% of the UC patients with Western blot technique, 47,000 polypeptide being the most common and making up 22.41% of them. CONCLUSION: The detection of ANCA was an auxiliary method for the diagnosis of UC. At present, UC-associated target antigens were not yet clarified, 47,000 polypeptide may be one of them. ANCA may participate in the pathogenesis of UC.

Adolescent↗
PubMed1999

[Preliminary studies on microwave irradiation ELISA for diagnosis of Schistosomiasis japonica].

AIM: To explore a fast and highly efficient method for the diagnosis of schistosomiasis japonica. METHODS: Using microwave irradiation ELISA (MWI-ELISA) and fast-ELISA to detect specific antibodies in sera from 118 cases with schistosomiasis japonica, 61 healthy individuals and 12 paragonimiasis cases. RESULTS: The positive rates of schistosomiasis cases were 88.1% (104/118) by MWI-ELISA and 91.5% (108/118) by fast-ELISA, respectively (chi 2 = 0.74, P > 0.05). The false positive reaction of healthy individuals was found in 2 cases(3.3%) by MWI-ELISA and 1 case (1.6%) by fast-ELISA, respectively (chi 2 = 0.34, P > 0.05). No false positive reaction was found in paragonimiasis cases. CONCLUSION: The sensitivity and specificity of the two tests were similar, however, MWI-ELISA was faster than fast-ELISA.

Animals↗
PubMed1999

Overexpression of c-fos and Rb proteins in radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcers in rats irradiated with 35 to 55 Gy y-rays. The pathological changes were observed for 1 year. Immunohistochemical studies were performed on 72 radiation-induced skin ulcer specimens using c-fos and Rb protein polyclonal antibodies. We found that the overexpression rate of c-fos was 45.8% and of Rb was 63.9%. The overexpression of c-fos was mainly seen in the nuclei of activated squamous epithelial cells and in some fibroblasts and endothelial cells of arterioles in the deep part of the skin ulcers. The overexpression of Rb had the same localization. Our results suggest that the changes in c-fos and Rb proteins may be related to the poor healing of radiation-induced skin ulcers.

Animals↗
PubMed1999

Overexpression of c-erbB-2 and EGF-R proteins in radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcers in rats irradiated with 35-55Gy gamma-rays. The pathological changes were studied for 1 year. Immunohistochemical studies were performed on 72 radiation-induced skin ulcer specimens using c-erbB-2 and epidermal growth factor receptor (EGF-R) protein antibodies. We found that the overexpression rate of c-erbB2 oncoprotein was 59.7% and of EGF-R was 70.8%. The overexpression of c-erbB-2 was chiefly seen in the activated squamous epithelial cells and in the cytoplasm of fibroblasts, endothelial cells, and leiomyocytes of the arteriolar media in the deep part of the ulcers. The overexpression of EGF-R had the same localizations. It is suggested that the overexpression of c-erbB-2 and EGF-R proteins may be due to the poor healing of the radiation-induced skin ulcers.

Animals↗
PubMed1999

Overexpression of p53 and MDM2 proteins in rat radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcer in rats that were locally irradiated with 35 to 55 Gy gamma-rays. The pathological changes were observed for 1 year. Immunohistochemical studies using p53 and MDM2 protein polyclonal antibodies were performed on 72 radiation-induced skin ulcer specimens. The results showed that the overexpression rate of p53 protein was 9.7% and of MDM2 was 19.4%. The overexpression of p53 was chiefly seen in the nuclei of the activated squamous epithelial cells and in the fibroblasts and endothelial cells of arterioles in the deeper part of the skin ulcers. The overexpression of MDM2 had the same localizations. These results suggest that the changes of p53 and MDM2 may be related to the poor healing rate of radiation-induced skin ulcers.

Animals↗
PubMed1998

[Sequencing analysis of human K-ras oncogene exon 1 in Chinese people].

OBJECTIVE: To investigate the mutation of human K-ras oncogene in the blood of patients with lung cancer. METHODS: PCR and sequencing methods were used to analyse the exon 1. Twelve patients'blood samples and 31 normals' blood samples were detected. RESULTS: In all 43 samples, the K-ras codon 11 was CCT (proline), and the opposite strand sequenced was AGG. It was different from the standard GCT(Alanine) sequenced by foreign authors. CONCLUSION: The 11th codon of the human K-ras oncogene in Chinese is CCT (Proline). As the K-ras codon 12 is a hot spot, this finding may be of importance to clinical genetic diagnosis.

Asian People↗
PubMed1998

Effects of tetrodotoxin treatment in LGN on neuromodulatory receptor expression in developing visual cortex.

The expression and distribution patterns of transmitter receptors change dramatically during pre- and post-natal development of the visual cortex, but the factors that control these processes are largely unknown. We have tested the hypothesis that input activity from the lateral geniculate nucleus (LGN), one major input source to visual cortex, may contribute to the processes underlying transmitter receptor redistributions in the visual cortex during development. We found that a short period of tetrodotoxin (TTX) treatment in LGN retarded the developmental expression and age-dependent reorganization of neuromodulatory receptors, including muscarinic, serotonergic and adrenergic receptors, in kitten primary visual cortex. The visual cortices ipsilateral to the TTX infusion site displayed a 'younger' receptor pattern than that of their contralateral control counterparts in the same animals. The results suggest that active input from LGN regulates the expression profile of a broad range of receptors in the developing visual cortex.

Animals↗
PubMed1998

Novel mechanism for non-genomic action of 17 beta-oestradiol on kainate-induced currents in isolated rat CA1 hippocampal neurones.

1. Using whole-cell voltage-clamp recordings of dissociated hippocampal CA1 neurones, we demonstrated that 17 beta-oestradiol rapidly potentiates kainate-induced currents when applied either to the outside or the inside of the neurone. However, when the steroid was conjugated to bovine serum albumin (E2-BSA), application to either the extracellular plasma membrane (E2-BSAout) or the cytosolic side of the cell (E2-BSAin) had no observable effect on kainate-induced currents. However, when applied stimultaneously to both sides of the plasma membrane, E2-BSA potentiated kainate-induced currents. 2. Application of E2-BSAout and GTP gamma S(in) potentiated kainate-induced currents. The potentiation of kainate-induced currents by 17 beta-oestradiol was occluded by cholera toxin pretreatment and appeared to be pertussis toxin insensitive. 3. E2-BSAin prolonged the effect of 8-bromoadenosine 3',5' cyclic monophosphate (8-bromo-cAMP) on kainate-induced currents. The recovery from the 8-bromo-cAMP response was found to be a function of the concentration of E2-BSAin. The application of ATP gamma S(in) occluded the effect of 17 beta-oestradiol. 4. These results suggest that the non-genomic action of 17 beta-oestradiol in the potentiation of kainate-induced currents is mediated via an action on Gs protein-coupled receptors. This operates in concert with an internal action of 17 beta-oestradiol on a cAMP-dependent phosphorylation.

Animals↗
PubMed1998

Activating Smoothened mutations in sporadic basal-cell carcinoma.

Basal-cell carcinomas (BCCs) are the commonest human cancer. Insight into their genesis came from identification of mutations in the PATCHED gene (PTCH) in patients with the basal-cell nevus syndrome, a hereditary disease characterized by multiple BCCs and by developmental abnormalities. The binding of Sonic hedgehog (SHH) to its receptor, PTCH, is thought to prevent normal inhibition by PTCH of Smoothened (SMO), a seven-span transmembrane protein. According to this model, the inhibition of SMO signalling is relieved following mutational inactivation of PTCH in basal-cell nevus syndrome. We report here the identification of activating somatic missense mutations in the SMO gene itself in sporadic BCCs from three patients. Mutant SMO, unlike wild type, can cooperate with adenovirus E1A to transform rat embryonic fibroblast cells in culture. Furthermore, skin abnormalities similar to BCCs developed in transgenic murine skin overexpressing mutant SMO. These findings support the role of SMO as a signalling component of the SHH-receptor complex and provide direct evidence that mutated SMO can function as an oncogene in BCCs.

Adenovirus E1A Proteins↗
PubMed1998

Histochemical mapping of NADPH-diaphorase in monkey and human eyes.

PURPOSE: To localize nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) in normal human and monkey eyes. METHODS: NADPH-d activity in ocular tissue sections was revealed by histochemical staining. RESULTS: NADPH-d staining was found in the anterior and posterior ocular segment of both species. In the anterior segment, reaction product was present in the corneal epithelium and endothelium, iris dilator and sphincter, lens capsule, ciliary muscle, and non-pigmented epithelial cells and stroma of the ciliary processes. Staining density in the longitudinal ciliary muscle was higher than in the other ciliary muscle regions in the human; such regionalization was less apparent in the monkey. The trabecular meshwork stained minimally if at all in both species. In the posterior segment, staining was seen around choroidal blood vessels and choroidal nerves, and in the retinal pigment epithelial, photoreceptor, bipolar, inner plexiform and ganglion cell layers. CONCLUSIONS: NADPH-d is widespread in human and monkey eyes, indicating significant and presumably functionally relevant NO production in the various ocular structures.

Adolescent↗
PubMed1998

The FRUITFULL MADS-box gene mediates cell differentiation during Arabidopsis fruit development.

Fruit morphogenesis is a process unique to flowering plants, and yet little is known about its developmental control. Following fertilization, fruits typically undergo a dramatic enlargement that is accompanied by differentiation of numerous distinct cell types. We have identified a mutation in Arabidopsis called fruitfull (ful-1), which abolishes elongation of the silique after fertilization. The ful-1 mutation is caused by the insertion of a DsE transposable enhancer trap element into the 5' untranslated leader of the AGL8 MADS-box gene. beta-glucuronidase (GUS) reporter gene expression in the enhancer trap line is observed specifically in all cell layers of the valve tissue, but not in the replum, the septum or the seeds, and faithfully mimics RNA in situ hybridization data reported previously. The lack of coordinated growth of the fruit tissues leads to crowded seeds, a failure of dehiscence and, frequently, the premature rupture of the carpel valves. The primary defect of ful-1 fruits is within the valves, whose cells fail to elongate and differentiate. Stomata, which are frequent along the epidermis of wild-type valves, are completely eliminated in the ful mutant valves. In addition to the effect on fruit development, ful cauline leaves are broader than those of wild type and show a reduction in the number of internal cell layers. These data suggest that AGL8/FUL regulates the transcription of genes required for cellular differentiation during fruit and leaf development.

Arabidopsis↗
PubMed1998

[Absolute configuration of the diastereoisomer of 2-amino-3-(1,2-dicarboxyethylthio) propanoic acid from Amanita pantherina].

Four stereoisomers of 2-amino-3-(1,2-dicarboxyethylthio) propanoic acid were prepared by reaction of L- and D-cysteine with fumaric acid. The absolute configuration of the diastereoisomer of 2-amino-3-(1,2-dicarboxyethylthio) propanoic acid from Amanita pantherina were assigned as (2R, 1'R) and (2R, 1'S) by analysis of the optical properties. Pharmacological tests showed that all of the four stereoisomers inhibited the depolarization of NMDA on spinal motorneurones in newborn rats, The inhibition intensity of L-A, D-A and D-B were higher than that of L-B.

Amanita↗