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Biomedical subjects

Y Su

Publications and source records attributed to Y Su.

At least 145 records · Page 8Linked to original sources
PubMed1997

Taurine influx in cultured rat cardiomyocytes and changes after CVB3 infection.

Monolayer culture of spontaneously contracting rat heart cells was obtained from newborn SD rats and seeded into culture plates. 100TCID50 of coxsackie virus B3(CVB3) (Nancy strain) was added as the infected group. The dynamics of taurine transport across membrane of normal heart cells and changes after infection were examined by using radioactive isotope tracing techniques. The results demonstrated that: (1) two uptake systems of taurine with different affinities and capacities were present in the plasma membrane of cultured rat cardiomyocytes, the Km of high and low affinity were 9.5 x 10(-5) mol/L and 1.3 x 10(-2) mol/L, respectively; (2) taurine transport across membrane was sodium-dependent with a positive linear relationship between amount of taurine influx and extracellular concentration of sodium; in addition, it was also regulated by osmolarity; (3) beta-alanine, a carboxylic analog of taurine, could inhibit the uptake of taurine in dose-dependently; (4) taurine influx was decreased in cultured rat cardiomyocytes after infected with CVB3. (5) the Inhibition ratio of taurine transport was enhanced as the infected time prolonged. This experiment provides a basis for further investigation of kinetic test of taurine transport and more study should be carried out to learn the effect of taurine in viral myocarditis.

Animals↗
PubMed1997

Use of microgenomic technology for analysis of alterations in DNA copy number and gene expression in malignant melanoma.

Chromosome abnormalities in human malignancies have identified the genomic location of several important growth-regulatory genes, including cellular oncogenes and tumour suppressor genes. Melanomas are characterized by recurring chromosome alterations, and it is important to identify those genes whose altered expression may be causally related to melanocytic transformation. This short report presents an overview of strategies used which combine the materials and technologies of the Human Genome Project with clinically directed studies of melanoma biology. The Human Genome Project combines various technologies, including cytogenetic, physical mapping, genetic mapping and DNA sequencing, in order to identify all of the human genes, but especially the 4000 estimated to contribute to human disease. This report focuses first on advances in genome technology that provide information on chromosome rearrangements and DNA copy number changes. This includes a discussion of chromosome microdissection as well as the microexcision of tissue specimens to gain insights into chromosome regions altered in association with melanocyte transformation. Next, there is a brief discussion of the generation and characterization of subtracted cDNA sublibraries which allow the identification of genes uniquely expressed in association with the transformed phenotype of human melanoma cells. Finally, we briefly discuss the feasibility of using a recently developed system for parallel examination of multiple genes based upon robotic printing of cDNAs on glass slides, and simultaneous two-colour fluorescence hybridization to study the expression patterns of cDNAs for their association with melanoma tumour suppression. The combination of these varied molecular technologies may provide insights into previously unrecognized genes involved causally in the pathobiology of this important neoplasm, and may provide new targets for clinical intervention.

Chromosome Mapping↗
PubMed1997

[Establishment and characterization of a xenografted human cervical carcinoma in nude mice and homologous cell line in vitro].

OBJECTIVE: To establish a xenografted tumor strain of human cervical carcinoma in nude mice and homologous cell line in vitro. METHODS: A human well differentiated cervical squamous cell carcinoma derived from a surgical specimen was transplanted in the subcutis of nude mice. The xenograft was cultured to establish a cell line in vitro. A series of characteristics of the grafts and the cells were examined. The established cell line was cloned by single cell detaching flask. Non-serum culture of the cells was tried. RESULTS: The xenografts were successively passaged for 26 generations during a period of 17 months. A tumor strain HCC-94V was established, having a high rate of successful inoculation rate (92.9%) and was growing steadily. The morphological and biological characteristics of its original tumor were preserved. The chromosomal analysis revealed a human aneuploid pattern of 9-120 in number. The tumor markers detected by immunocytochemical techniques showed high expression, the oncogenic products, low expression. Polymerase chain reaction (PCR) showed the same results as those of the patients with original tumor tissue, human papilloma virus (HPV) 16 (+), 18 (-). A new human cell line HCC-94 derived from the xenograft, was established and maintained for 16 months through 131 passages. Transmission electromicroscopy demonstrated the presence of typical desmosomes between the cells and many tonofilaments in the cells. Also, the morphology of chromosomes showed the characteristics of chromosomes as well as of mutants in the human tumor cells. The tumor markers and the oncogenic products of the cells exhibited higher expression than that of the original tumor. The HPV 16 and 18 of the cells, using PCR, were negative. The cells were highly tumorigenic in nude mice. The transplanted tumors resembled the original tumor tissues in morphology and were HPV 16 positive. Both cell cloning culture and non-serum culture of HCC-94 were successful. CONCLUSION: HCC-94V and HCC-94 could be considered as a new xenografted tumor strain may provide material and model ideal for further investigation of human cervical carcinoma.

Adult↗
PubMed1997

[Renin-angiotensin system: involvement in polycystic ovarian syndrome].

OBJECTIVE: To investigate the relationship between renin-angiotensin system (RAS) and polycystic ovarian syndrome (PCOS) METHODS: A pituitary-stimulating test with luteinizing hormone releasing hormone (LRH, 100 micrograms) was performed in two PCOS groups with similar mean testosteron (T) levels of luteinizing hormone/follicular stimulating hormone (LH/FSH) (LH/FSH > or = 3, group 1, n = 15; LH/FSH < 3, group 2, n = 15) and the controls (n = 20) of matched body mass index with group 1. The basal level and LRH-evoked responses of LH, plasma renin activity (PRA), angiotensin II (AT II ) and aldosterone (ALD) were measured by RIA with commercially available kits. In the basal state, a positive correlation was found between T and AT II levels (r = 0. 49, P < 0.05) in all PCOS subjects. After LRH administration, susceptible individuals, especially of group 1 had exaggerated responses of LH, PRA, AT II and ALD as compared with the controls, and a positive correlation was also found between peak levels of LH and AT II (r = 0.54, P < 0.01). CONCLUSIONS: There is enhanced RAS function in PCOS especially in group 1. This may contribute to the excess androgen production and high incidence of ovarian hyperstimulation syndrome in this disorder.

Adult↗
PubMed1997

[Responses of growth hormone and prolactin to L-Dopa in women with polycystic ovarian syndrome].

OBJECTIVE: To evaluate the altered dopaminergic modulation of growth hormone (GH) and prolactin (PRL) in polycystic ovarian syndrome (PCOS). METHODS: Responses of GH and PRL to L-Dopa (L-DA) (500 mg) were observed in two PCOS groups (LH/FSH > or = 3, Group I, n = 15, LH/FSH < 3, Group II, n = 15) and the control (n = 20). RESULTS: Significantly lower GH (P < 0.01) and higher PRL levels (P < 0.05 in group I) in the basal state, and lower responses of GH and PRL to L-DA were found in two PCOS groups as compared with the control. CONCLUSION: The altered basal levels and blunted L-DA evoked responses of GH and PRL suggest a relative decrease of the dopaminergic activity in PCOS patients.

Adult↗
PubMed1997

[The changes of T lymphocyte subsets and serum interleukin-2 receptor in peripheral blood of the pregnant women complicated by systemic lupus erythematosus].

OBJECTIVE: To determine the changes of T lymphocyte subsets, natural killer (NK) cell and serum interleukin-2 receptor (SIL-2R) in peripheral blood of the pregnant women with systemic lupus erythematosus (SLE). METHODS: T lymphocyte subsets NK cell, and SIL-2R in peripheral blood were detected by flow cytometry (FCM) and enzyme-labeled immunosorbent assay (ELISA) in 14 cases of pregnant women complicated by SLE (SLE+NP), 18 cases of stationary phase SLE (SLE), 20 cases of normal non-pregnant women (NNP) and 20 cases of normal pregnant women (NP). RESULTS: The percentages of CD4+ cell were decreased significantly in SLE+NP group as compared with the other three groups (P < 0.01); and the ratio of CD4+/CD8+ was decreased significantly in SLE+NP group, as compared that in SLE group and in NNP group (P < 0.01). There were no difference in the number of NK cells among the four groups. The SIL-2R values were found to be increased significantly in the SLE+NP group, as compared with that of other three groups (P < 0.01). CONCLUSION: The observation on the changes of peripheral T lymphocyte subsets and SIL-2R may be helpful for monitoring progress of SLE during pregnancy.

Adult↗
PubMed1996

Results of MDR-1 vector modification trial indicate that granulocyte/macrophage colony-forming unit cells do not contribute to posttransplant hematopoietic recovery following intensive systemic therapy.

To formally test the hypothesis that the granulocyte/macrophage colony-forming unit (GM-CFU) cells can contribute to early hematopoietic reconstitution immediately after transplant, the frequency of genetically modified GM-CFU after retroviral vector transduction was measured by a quantitative in situ polymerase chain reaction (PCR), which is specific for the multidrug resistance-1 (MDR-1) vector, and by a quantitative GM-CFU methylcellulose plating assay. The results of this analysis showed no difference between the transduction frequency in the products of two different transduction protocols: "suspension transduction" and "stromal growth factor transduction." However, when an analysis of the frequency of cells positive for the retroviral MDR-1 vector posttransplantation was carried out, 0 of 10 patients transplanted with cells transduced by the suspension method were positive for the vector MDR-1 posttransplant, whereas 5 of 8 patients transplanted with the cells transduced by the stromal growth factor method were positive for the MDR-1 vector transcription unit by in situ or in solution PCR assay (a difference that is significant at the P = 0.0065 level by the Fisher exact test). These data suggest that only very small subsets of the GM-CFU fraction of myeloid cells, if any, contribute to the repopulation of the hematopoietic tissues that occurs following intensive systemic therapy and transplantation of autologous hematopoietic cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Ordered shotgun sequencing of a 135 kb Xq25 YAC containing ANT2 and four possible genes, including three confirmed by EST matches.

Ordered shotgun sequencing (OSS) has been successfully carried out with an Xq25 YAC substrate. yWXD703 DNA was subcloned into lambda phage and sequences of insert ends of the lambda subclones were used to generate a map to select a minimum tiling path of clones to be completely sequenced. The sequence of 135 038 nt contains the entire ANT2 cDNA as well as four other candidates suggested by computer-assisted analyses. One of the putative genes is homologous to a gene implicated in Graves' disease and it, ANT2 and two others are confirmed by EST matches. The results suggest that OSS can be applied to YACs in accord with earlier simulations and further indicate that the sequence of the YAC accurately reflects the sequence of uncloned human DNA.

Bacteriophage lambda↗
PubMed1996

cGMP mediates the vascular and platelet actions of nitric oxide: confirmation using an inhibitor of the soluble guanylyl cyclase.

The L-arginine:nitric oxide (NO) pathway is believed to exert many of its physiological effects via stimulation of the soluble guanylyl cyclase (SGC); however, the lack of a selective inhibitor of this enzyme has prevented conclusive demonstration of this mechanism of action. We have found that the compound 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ) inhibits the elevation of cGMP induced by the NO donor S-nitroso-DL-penicillamine in human platelets and rat vascular smooth muscle (IC50 = 10-60 nM and <10 nM, respectively) and that this is accompanied by prevention of the platelet inhibitory and vasodilator actions of NO donors. ODQ also inhibited the antiaggregatory action of NO generated by the platelets but did not affect the action of prostacyclin or that of a cGMP mimetic. In addition, ODQ inhibited the vasodilator actions of endogenously released NO and of NO generated after induction of NO synthase in vascular preparations. It did not, however, affect the increase in vascular smooth muscle cGMP or the dilatation induced by atrial natriuretic factor. ODQ had no effect on NO synthase activity, nor did it react with NO. It did, however, potently (IC50 approximately 10 nM) inhibit the activity of the SGC in cytosol obtained from crude extract of rat aortic smooth muscle. Thus ODQ prevents the actions of NO on platelets and vascular smooth muscle through its potent inhibitory effect on the SGC.

Animals↗
PubMed1996

Altered structural and mechanistic properties of mutant dihydropteridine reductases.

Nine single genetic mutants of rat dihydropteridine reductase (EC 1.6.99.7), D37I, W86I, Y146F, Y146H, K150Q, K150I, K150M, N186A, and A133S and one double mutant, Y146F/K150Q, have been engineered, overexpressed in Escherichia coli and their proteins purified. Of these, five, W86I, Y146F, Y146H, Y146F/K150Q, and A133S, have been crystallized and structurally characterized. Kinetic constants for each of the mutant enzyme forms, except N186A, which was too unstable to isolate in a homogeneous form, have been derived and in the five instances where structures are available the altered activities have been interpreted by correlation with these structures. It is readily apparent that specific interactions of the apoenzyme with the cofactor, NADH, are vital to the integrity of the total protein tertiary structure and that the generation of the active site requires bound cofactor in addition to a suitably placed W86. Thus when the three major centers for hydrogen bonding to the cofactor are mutated, i.e. 37, 150, and 186, an unstable partially active enzyme is formed. It is also apparent that tyrosine 146 is vital to the activity of the enzyme, as the Y146F mutant is almost inactive having only 1.1% of wild-type activity. However, when an additional mutation, K150Q, is made, the rearrangement of water molecules in the vicinity of Lys150 is accompanied by the recovery of 50% of the wild-type activity. It is suggested that the involvement of a water molecule compensates for the loss of the tyrosyl hydroxyl group. The difference between tyrosine and histidine groups at 146 is seen in the comparably unfavorable geometry of hydrogen bonds exhibited by the latter to the substrate, reducing the activity to 15% of the wild type. The mutant A133S shows little alteration in activity; however, its hydroxyl substituent contributes to the active site by providing a possible additional proton sink. This is of little value to dihydropteridine reductase but may be significant in the sequentially analogous short chain dehydrogenases/reductases, where a serine is the amino acid of choice for this position.

Amino Acid Sequence↗
PubMed1996

Acute hypoxia increases intracellular L-arginine content in cultured porcine pulmonary artery endothelial cells.

Exposure to hypoxia (0% O2) for 4-24 h resulted in increased intracellular L-arginine content and increased activity of calpain, a calcium-dependent neutral cysteine protease, in pulmonary artery endothelial cells. Calpain-inhibitor I abolished the increased L-arginine content in hypoxic cells. When endothelial cell proteins were labeled with [3H]-L-arginine and the cells exposed to hypoxia, we observed an increase in free [3H]-L-arginine and a decrease in [3H]-L-arginine-labeled proteins. Once again, calpain-inhibitor I prevented the increases in free [3H]-L-arginine and the decreases in [3H]-L-arginine-labeled proteins in hypoxic cells. Hypoxia also inhibited the synthesis of L-arginine-containing proteins. Thus, the increase in intracellular L-arginine content in hypoxic pulmonary artery endothelial cells is caused by an increase in proteolysis secondary to calpain and a decrease in protein synthesis. These results indicate that hypoxia can modulate the availability of free intracellular L-arginine, the exclusive precursor of nitric oxide (NO) and the primary substrate of NO synthase, by affecting the synthesis and degradation of cellular proteins.

Animals↗
PubMed1996

Involvement of sphingolipids metabolites in cellular proliferation modulated by ganglioside GM1.

The B subunit of cholera toxin, which binds specifically to ganglioside GM1, is mitogenic for quiescent Swiss 3T3 fibroblasts. Recently, sphingolipids metabolites, ceramide, sphingosine and sphingosine-1-phosphate, have been implicated as second messengers in cell growth regulation and differentiation. In this paper, we examined the possibility that interaction of the B subunit with membrane GM1 leads to alterations in metabolism of glycosphingolipids and that increased levels of sphingolipids metabolites may mediate the biological effects of the B subunit. While the B subunit did not induce a change in the level of ceramide or sphingosine, the level of sphingosine-1-phosphate was rapidly and transiently increased. The B subunit also transiently activated cytosolic sphingosine kinase activity, which catalyzes the phosphorylation of the primary hydroxyl group of sphingosine to produce sphingosine-1-phosphate. To determine whether the increase in sphingosine-1-phosphate level plays a role in B subunit-induced mitogenicity, we used a competitive inhibitor of sphingosine kinase, D,L-threo-dihydrosphingosine. D,L-thereo-Dihydrosphingosine not only inhibited B subunit-induced DNA synthesis by 26%, it also reduced its ability to stimulate DNA-binding activity of the transcription factor AP-1. This sphingosine kinase inhibitor also inhibited B subunit-induced increases in the activity of cell cycle-regulated, cyclin-dependent serine/threonine kinases, cdk2 and p34cdc2. These findings suggest that sphingosine-1-phosphate may play a role in the signal transduction pathways activated by binding of the B subunit to endogenous ganglioside GM1.

3T3 Cells↗
PubMed1996

Endocrine and behavioral effects of airpuff-startle in rats.

Adult male rats chronically implanted with cannulae in the jugular vein were used to characterize the endocrine and behavioral consequences of airpuff-startle. In the first series of experiments, resting animals subjected to three blocks of airpuff (blocks of three airpuffs each with each block separated by 1 min) showed a 10-fold increase in plasma adrenocorticotropin (ACTH) and corticosterone levels, indicating a significant but moderate activation of the hypothalamo-pituitary-adrenal (HPA) axis when compared with the untreated controls (n = 5 each). In the second series of experiments, monitoring of anxiety-related behavior in the defensive withdrawal paradigm revealed a significant increase in anxiety induced by airpuff-startle application compared with the untreated controls (n = 10 each). This behavioral effect, however, was not correlated with plasma hormone levels, as blood samples taken immediately before and 12 min after exposure to airpuff-startle and exposure to the defensive withdrawal paradigm showed a significant rise in ACTH and corticosterone in both groups. In summary, the findings of the present study indicate the airpuff-startle (1) is a potent stimulus in the activation of the HPA axis, and (2) increases anxiety-related behavior as measured in the defensive withdrawal paradigm. Furthermore, the results of our study support the hypothesis that peripheral endocrine parameters that are used to measure activation of the HPA axis do not necessarily correlate with behavioral data obtained in tests with are thought to measure anxiety.

Adrenocorticotropic Hormone↗
PubMed1996

[Study on combined acupunctural and general anesthesia in pneumonectomy].

Combined acupunctural and general anesthesia in pneumonectomy were studied. The result showed that general anesthesia complemented with electro-acupuncture at He Gu (LI 4) and San Yang Luo(SJ 8) reduced amount of Fentanyl 38-85 micrograms/h compared with general anesthesia alone. There were no statistical difference in blood pressure and heart rate during the operation in every group, all of the SPO2 were in normal range. It was considered that acupuncture in combination with general anesthesia could reduce dosage of anesthetics and the inhibition of physiological function. It is a practical and acceptable anesthetic method by the surgeon and patient.

Acupuncture Analgesia↗
PubMed1996

[Protective effect of ATP-MgCl2 on gut mucosa in burn rat].

In order to study the protective effect of ATP-MgCl2 on gut mucosal barrier function in trauma-induced stressed animal, full thickness burn of 30% total body surface area (TBSA) was produced in rats, and ATP-MgCl2 was injected intraperitoneally right after scald-injury. Malondialdehyde (MDA) contents of ileum mucosa were determined and morphological alteration in the ileum was observed under light microscope. The results showed that ileum mucosal MDA content increased significantly, accompanied by obvious morphological change, after the injury, whereas MDA content was maintained at the normal control level and pathological alteration in ileum tissue was abated after the use of ATP-MgCl2. It suggests that ATP-MgCl2 possesses a protective effect on gut mucosal barrier function of scald-injured rat, and the mechanism involved may be related to the inhibition of lipid peroxidation in gut mucosa.

Adenosine Triphosphate↗
PubMed1996

[Prediction of skin flap viability by laser Doppler scanning].

Twelve female pigs were used for the experiment. An island flap (8 cm x 15 cm) pedicled with the superficial circumflex iliac vessels was elevated on the flank of the pig. The blood flow of the flap was measured with laser doppler scanning at different times, i.e. before and after flap elevation; before clipping the feeding artery of the flap and 9 hours after clipping the artery; 5 minutes, 20 minutes, 40 minutes, 1 hour and 40 hours after reperfusion. The flap viability was also examined with naked eye and fluorography. Biopsy examinations were used as gold standard of flap viability. The results showed that predicting accuracy of flap viability by naked eye was 76%; fluorography was 94% and laser doppler scanning was 91.3%. No significant difference was found between the results from fluorography and laser doppler scanning while there was significant difference between naked eye and laser doppler scanning. The authors discussed the clinical applications of predicting skin flap viability.

Animals↗