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Biomedical subjects

S L Zhang

Publications and source records attributed to S L Zhang.

At least 55 records · Page 3Linked to original sources
PubMed1998

Molecular mechanism(s) of action of norepinephrine on the expression of the angiotensinogen gene in opossum kidney cells.

BACKGROUND: Norepinephrine (NE) is the major endogenous neurotransmitter of the renal sympathetic nerves interacting with both the alpha- and beta-adrenoceptors in the renal proximal tubules. We have previously reported that isoproterenol and iodoclonidine stimulate the expression of the angiotensinogen (ANG) gene in opossum kidney (OK) proximal tubular cells via the beta1-adrenoceptor and alpha2-adrenoceptor, respectively. We hypothesized that NE may interact with the beta- and/or alpha2-adrenoceptors to stimulate the expression of the ANG gene in OK cells. METHODS: The fusion genes containing the various lengths of the 5'-flanking regulatory sequence of the rat ANG gene fused with a human growth hormone (hGH) gene as a reporter were stably transfected into the OK cells. The stimulatory effect of NE on the expression of the fusion genes was evaluated by the amount of immunoreactive hGH (IR-hGH) secreted into the culture medium. RESULTS: The addition of NE stimulated the expression of the fusion gene, pOGH (ANG N-1498/+18) in a dose-dependent manner. The stimulatory effect of NE was inhibited in the presence of propranolol, atenolol, Rp-cAMP, yohimbine, staurosporine, H-7 and U73122 but not in the presence of ICI 118,551 and prazosin. The addition of a combination of isoproterenol and iodoclonidine synergistically stimulated the expression of pOGH (ANG N-1498/+18) as compared to the addition of isoproterenol and iodoclonidine alone. Furthermore, the addition of NE, forskolin, 8-Br-cAMP or phorbol 12-myristate (PMA) stimulated the expression of pOGH (ANG N-806/-779/-53/+18), a fusion gene containing the putative cAMP responsive element (CRE, ANG N-806/-779) upstream of the ANG promoter (ANG N-53/+ 18) in OK 95 cells, but had no effect on the expression of fusion genes containing the mutant of the CRE. CONCLUSION: These studies demonstrate that the stimulatory effect of NE on the expression of the ANG gene in OK cells may be mediated via both the beta1- and alpha2-adrenoceptors and via the CRE (ANG N-806/-779) in the 5'flanking region of rat ANG gene.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1998

Synergistic effect of dexamethasone and isoproterenol on the expression of angiotensinogen in immortalized rat proximal tubular cells.

To investigate whether the expression of angiotensinogen (ANG) in rat kidney proximal tubules is stimulated by dexamethasone and isoproterenol, immortalized rat proximal tubular cells (IRPTC) were cultured in a monolayer. Immunoreactive rat ANG (IR-rANG) in the culture medium was measured by a specific radioimmunoassay (RIA) for rANG. This RIA was developed by employing rabbit antiserum against the purified recombinant rat ANG (rANG). The purified rANG from plasma and the iodinated rANG were used as the hormone standard and tracer, respectively. The RIA is specific for rat ANG and it has no cross-reactivity with other pituitary hormone preparations or other rat plasma proteins. The sensitivity of detection of the RIA is approximately 2 ng of rANG. The levels of IR-rANG in the culture media of IRPTC ranged from 2 to 5 ng/ml/24 hr/10(6) cells. The addition of dexamethasone (10(-13) to 10(-5) M) stimulated the expression and secretion of rANG from IRPTC in a dose-dependent manner, whereas the addition of isoproterenol alone had no effect. However, a combination of both dexamethasone and isoproterenol synergistically stimulated the expression and secretion of rANG by IRPTC. The synergistic effect of dexamethasone and isoproterenol was blocked by the presence of RU 486 (a glucocorticoid receptor antagonist) or propranolol (beta-adrenoceptor blocker). These studies suggest that the addition of dexamethasone and isoproterenol acts synergistically to stimulate the expression and secretion of ANG protein in rat proximal tubules in vivo.

Adrenergic beta-Agonists↗
PubMed1998

Effect of glucose on the expression of the angiotensinogen gene in opossum kidney cells.

To investigate whether D(+)-glucose has a stimulatory effect on the expression of the angiotensinogen (Ang) gene in opossum kidney (OK) cells, we used OK cells with a fusion gene containing various lengths of the 5'-flanking regulatory sequence of the rat Ang gene fused with the human growth hormone (hGH) gene as a reporter, stably integrated into their genomes. The level of expression of the fusion gene was quantified by the amount of immunoreactive-human growth hormone (IR-hGH) secreted into the medium. The addition of D(+)-glucose stimulated the expression of pOGH (Ang N-1498/+18) in OK 27 cells in a dose-dependent manner (5 to 25 mM), whereas the addition of D-mannitol, L-glucose and 2-deoxy-D-glucose (25 mM) had no effect. The stimulatory effect of D(+)-glucose (25 mM) was blocked by the presence of staurosporine or H7 (an inhibitor of protein kinase C) or U73122 (an inhibitor of phospholipase C and A2) but not blocked by the presence of Rp-cAMP (an inhibitor of cAMP-dependent protein kinase A). The addition of D(+)-glucose (25 mM) also stimulated the expression of pOGH (Ang N-960/+18) and pOGH (Ang N-688/+18) in OK 960 and OK 688 cells, respectively. It had no stimulatory effect, however, on the expression of pOGH (Ang N-280/+18) and pOGH (Ang N-35/+18) in OK 280 and OK 35 cells, respectively. The addition of D(+)-glucose also had no effect on the expression of pTKGH in OK 13 cells, an OK cell line, into which had been stably integrated a fusion gene, pTKGH containing the promoter/enhancer DNA sequence of the viral thymidine-kinase (TK) gene fused with a human growth hormone gene as a reporter. These studies demonstrate that the stimulatory effect of high D(+)-glucose concentration (25 mM) on the expression of the angiotensinogen-growth hormone fusion genes in OK cells is mediated via the 5'-flanking region of the angiotensinogen gene and the protein kinase C signal transduction pathway. Our data indicate that a high glucose concentration may activate the renin-angiotensin system in the renal proximal tubular cells.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1998

Effects of verapamil on down-regulation of norepinephrine-induced beta adrenoceptors in cultured rat cardiomyocytes.

AIM: To determine whether verapamil (Ver) inhibits norepinephrine (NE)-induced beta adrenoceptors down-regulation in cultured rat cardiomyocytes. METHODS: [3H]-Dihydroalprenolol (DHA) radiobinding assay was used to measure beta adrenoceptor density, fluorescent indicator Fura 2-AM was used to estimate levels of free cytosolic calcium ([Ca2+]i). RESULTS: Ver reduced [Ca2+]i and increased beta adrenoceptor density, NE increased [Ca2+]i and reduced beta adrenoceptor density of cultured cardiomyocytes, these effects were time and concentration dependent. Ver inhibited the above effects of NE. CONCLUSIONS: Ver increased beta adrenoceptor density and inhibited NE-induced beta adrenoceptor down-regulation of cardiomyocytes.

Adrenergic alpha-Agonists↗
PubMed1997

2',5'-Oligoadenylate synthetase activity and T cell subset in the cerebrospinal fluid and peripheral blood of aseptic meningitis.

2',5'-oligoadenylate synthetase activity, which is assumed to be induced by interferon, is reported to be one of the useful markers reflecting interferon activity. The enzyme activity of patients with aseptic meningitis and febrile convulsion were compared in order to evaluate interferon activity as one of the local immuno-defense mechanisms of aseptic meningitis. The surface antigen of mononuclear cells in cerebrospinal fluid and peripheral blood of some patients with aseptic meningitis was also measured. The enzyme activity of patients with aseptic meningitis was 191.4 pmol/dL in the cerebrospinal fluid and 395.8 pmol/dL in the serum during the acute phase, while that of patients with febrile convulsion was 45.2 pmol/dL in the cerebrospinal fluid and 326.0 pmol/dL in the serum. The enzyme activity of the former patients significantly decreased during the recovery phase in both the cerebrospinal fluid and serum. CD3 positive cells in the peripheral blood were 56.3% of the total mononuclear cells during the acute phase and 65.2% during the recovery phase, whereas in the cerebrospinal fluid mononuclear cells, they were 87.1 and 85.5%, respectively. During the acute phase, CD4 positive cells were the predominant T lymphocyte subset in the cerebrospinal fluid cells, while CD8 positive cells were predominant during the recovery phase. The relative proportions of CD4 positive and CD8 positive cells during the acute and recovery phase in the cerebrospinal fluid mononuclear cells were quite high compared to the recovery phase, although that ratio of peripheral blood mononuclear cells was not changed throughout the course. It was concluded that T lymphocytes and increased 2',5'-oligoadenylate synthetase activity in the cerebrospinal fluid may be one of the important components in the local inflammatory process independent of the systemic host defense mechanism in aseptic meningitis.

2',5'-Oligoadenylate Synthetase↗
PubMed1997

[Study on syndrome-type in TCM and its correlation with superoxide dismutase and malonyldialdehyde in patients with non-insulin dependent diabetes mellitus].

OBJECTIVE: To explore the possible relationship between Syndrome-Type in TCM and the superoxide dismutase (SOD) as well as malonyldialdehyde (MDA). METHODS: Serum SOD and MDA were measured in 61 patients with non-insulin dependent diabetes mellitus (NIDDM) and 20 normal subjects. RESULTS: SOD activity of the NIDDM patients blood were clearly lower than those of normal subjects, but MDA were markedly elevated. From the Syndrome-Type of Yin Deficiency with Hyperactivity of Heat, to both Qi and Yin Deficiency, to both Yin and Yang Deficiency, or from without hemostasis to with the appearance of hemostasis in order. The SOD activity decreased and meanwhile MDA increased gradually. CONCLUSIONS: SOD activity and MDA levels in patients with NIDDM were associated with Syndrome-Type in TCM, it might be responsible for the diagnosis of Syndrome-Type in TCM.

Adult↗
PubMed1997

[The study of influencing cellular dynamics of gynostemma pentaphyllum on golden hamster cheek pouch premalignancy]

Studying premalignancy is an important field of conquering cancer.The aim to study the mechanics of oral mucosal premalignant formation and seek effective drug which could prevent and block cancer,Gynostemma Pentaphyllum(GP) was applies to block carcinomatous conversion of golden hamster cheek pouch by Salley's way.Using light microscopic observation and proliferating cell nuclear antigen(PCNA) as well as bromodeoxyuridine(BrdU)(PCNA AND BrdU are immunohistochemistry techniques),GPs effect was observed dynamically.We found that GP could delay the presence of leukoplakia and decrease the rate of presence as well as cancer-causing rate. The positive cells of taking drug group PCNA and BrdU were lower than model group significantly and in a lower condition all the time.It is illustrated that GP has the effect of preventing cancer and inhibiting cellular dysplasia.

Journal Article↗
PubMed1997

[The study of cellular dynamic varied features on golden hamster cheek pouch premalignant model]

Researching the model of golden hamster cheek pouch premalignancy not only had significance on treating and preventing oral epithelial cancers,but also could furnish the reference material about other similar hidden tumors.In this study,immunohistochemistry ways(proliferation cell nuclear antigen-PCNA,bromodeoxyurdine-BRDU) combined with light and electric microscopic observation were applied to study cellular dynamic varied features on golden hamster cheek pouch premalignant model induced by dimethylbenzanthracence (DMBA).The results showed that both S-period cells and DAN's synthesis increased in the development of premalignancy,then,discovered the basis of cellular dynamics of the model.

Journal Article↗
PubMed1997

[Correlative analysis with proliferating cell nuclear antigen,bromodeoxyuridine,and microscopic observation on golden hamster carcinogenesis model]

The early diagnosis of carcinomatous conversion has special significance on increasing effectiveness.Proliferating cell nuclear antigen(PCNA),bromodeoxyuridine(BRDU)(immunohistochemistry ways),and microscopic diagnosis were applied and observed on golden hamster cheek pouch carcinogenisis model induced by dimethybenzanthracene(DMBA) in order to seek simple,effective,leading and reliable diagnostic way.The results showed that three observable means had significant correlation,and demonstrated that immunohistochemistry ways practical value in diagnosis of carcinomatous conversion.This study suggests that PCNA and BRDU are more sensitive,simple and reliable,and two hopeful methods of early diagnosis of carcinomatous conversion.

Journal Article↗
PubMed1997

[The light microscopic observing analysis of 12-item pathological features on golden hamster cheek pouch dysplasia]

Grading objectively serious degree of oral mucosal premalignancy has instructive significance to its outlook and effectiveness.In order to supply experimental foundation of diagnosis epithelial dysplasis accruately,the sample of golden hamster premalignancy induced by dimethyblenzanthracence(DMBA) were made and observed microscopically.The results were recorded one by one according to 12-item criteria of WHO.The results showed that 12-item criteria could summarized wholly the histopathological varied features in the every stage of epithelial dysplasia The frequency of occurrence of 12-itemcriterias suggests that the starting site of premalignancy be at the basal layer.Abnormal karyokinetic and mitogenic figures have special significance in the epithelial dysplasia of grading diagnosis and judging outlook.

Journal Article↗
PubMed1997

[Correlative analysis with proliferating cell nuclear antigen and bromodeoxyuridine on golden hamster carcinogenesis model]

The early diagnosis of carcinomatous conversion has special significance on increasing therapeutic effectivencess.Proliferating cell nuclearnatigen(PCNA),bromodexoyuridine(UrdU)(immunohistochemistry ways),and microscopic diagnosis were applied and observed on golden hamster cheek is pouch carcinogenisis model induced by dimethylbenzanthracene(DMBA) in order to seek simple,effective,leading and reliable diagnostic way.The results showed that three observable means had significant correlativity,and demonstrated that immunohistochemistry ways have practical value in diagnosis of carcinomatous conversion.This study suggests that PCNA and BrdU be more sensitive,simple and reliable,and hopeful methods of early diagnosis of carcinomatous conversion.

Journal Article↗
PubMed1997

[Effect of salvia miltiorrhiza composita on superoxide dismutase and malonyldialdehyde in treating patients with non-insulin dependent diabetes mellitus (NIDDM)].

OBJECTIVE: To assess the effect of Salvia Miltiorrhiza Composita (SMCo) in treating non-insulin-dependent diabetes mellitus (NIDDM). METHODS: The superoxide dismutase (SOD) and malonyldialdehyde (MDA) levels of 20 patients with NIDDM were observed before and after treatment with Salvia Miltiorrhiza Composita and 20 patients without using SMCo were studied as controls. RESULTS: The SOD levels were significantly lower than that of normal (P < 0.05), and MDA significantly increased (P < 0.01). After treatment with SMCo, the SOD levels were significantly increased (P < 0.01), there was no difference between the treatment group and the normal group. In the control group, the SOD levels had increase tendency and MDA had decrease tendency, but there was significant difference compared with the normal (P < 0.05, P < 0.01 respectively). The total effective rate of anti-lipid peroxidation injury in the group combined with intravenous SMCo was markedly higher than in the group without SMCo therapy (90% vs 60%, P < 0.01). CONCLUSION: SMCo could resist lipid peroxidation injury.

Adult↗
PubMed1996

[Analysis of the clinic with pathology and detection using IGSS of 201 cases of discoid lupus erythematosus]

Clinic pathology and detection using IGSS of 201 cases of discoid lupus erythematosus (DLE) were studied in this paper.The results showed:1.DLE usually occured on the low lip(60%);2.Suffering from gastrointestinal disease were the first symptom(25%DLE cases was confirmed by mild dysplasia,3 cases of carcinoma.1 cases Combined of DLE and lichen planus(LP);4.Immunogold-silver Staining (IGSS) was applied to detect immune complex.The result indicated that Fg,immunoglobins and complement C3 deposited at basal membrane zone of DLE.It is illustrated that DLE is an autoimmune disease which is caused by many kinds of factors and may be cancerous.Coexistence of DLE and LP suggested that they may be at different stages of the same disease.Its mechanism will be further studied.

Journal Article↗
PubMed1996

[Teatment of oral lichen planus with chloroquine and triamcinolone-A]

In this study,single blind grouping method was applied to compare the effect of chloroquine and triamcinolone-A which were used to treat 360 cases of oral lichen planus.The results showed the effect of local injecting triamcinolone-A was better than that of taking chloroquine,and also was better than that of taking triamcinolone-A accompained of chloroquine.Therefore,they were two effective ways to cure OLP and worthy of wide use.

Journal Article↗
PubMed1996

[Observation of the effectiveness of compound Gynostemma Pentaphyllum Mak in golden hamster cheek pouch's premalignancy]

Premalignant model was established successfully in this study.At the same time,we applied compound Gynostemma Pentaphyllum Mak to conduct experimental research to block development of oral mucosal premalignancy.The results showed from uniform to granular or verrucous leukoplakia,there was the stage in which Gynostemma Pentaphyllum Mak could block oral mucosal premalignancies.The group which was firstly given to Gynostemma Pentaphllum Mak then smeared was more advantageous than the one which firstly smeared then given to the same drug.The experimentation demonstrated that Gynostemma Pentaphyllum had the functions of preventing and resisting cancer.There will be applied prospect in preventing and treating oral mucosal premalignancy.We should make further research in the future.

Journal Article↗
PubMed1995

Mouse embryonic stem cells express receptors of the insulin family of growth factors.

Insulin and insulin-like growth factors (IGF-I and -II) are members of a family of growth factors which are known to be developmentally regulated during preimplantation mouse embryogenesis. The physiological actions of the insulin family of growth factors are mediated by interactions with specific cell surface receptors that are detectable on the cells of preimplantation mouse embryos. Mouse embryonic stem (ES) cells are totipotent cells derived directly from the inner cell mass of the blastocyst. ES cells have the ability to differentiate into all three germ layers and have unlimited growth potential under certain culture conditions. The great advantage of ES cells is the ability to obtain large amounts of tissue for biochemical studies as compared with preimplantation embryos. To examine in greater detail the biological actions of the insulin family of growth factors, the expression of their cognate receptors on ES cells was examined. ES cells were cultured in DMEM medium supplemented with leukemia inhibitory factor (LIF) to maintain the undifferentiated state. Receptor expression was evaluated at the mRNA level using the reverse transcription polymerase chain reaction (RT-PCR), and at the protein level by radioactive labeled ligand-receptor binding assay. Using RT-PCR, mRNAs of all three growth factor receptors were detected in ES cells. Messenger RNA from ES cells was reverse transcribed into cDNA by AMV reverse transcriptase at 42 degrees C for 1 hr. The reverse transcription reaction was amplified with Taq polymerase and specific primers for insulin, IGF-I, or IGF-II receptors by PCR. RT-PCR and the control plasmid cDNA PCR products were resolved electrophoretically on 3% agarose gels. Each amplified PCR product showed the predicted correct size.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗