In vivo characterization of changes in glycine levels induced by GlyT1 inhibitors.
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Amino Acid Transport Systems, Neutral↗
Biomedical subjects
Hong Yu
Publications and source records attributed to Hong Yu.
[Measurement of transient evoked otoacoustic emissions and follow-up of 215 healthy newborns].
OBJECTIVE: To evaluate the characteristics of transient evoked otoacoustic emissions (TEOAE) of healthy newborns and improve hearing screening of newborns. METHOD: To investigate the history of pregnancy and parturition, TEOAE was measured in 425 ears of 215 healthy newborns from 0 to 8 days postpartum and follow-up study was undertaken. RESULT: The general prevalence was 89%. There was some relationship between prevalence and testing time. The average prevalence was 74% in newborns of 0-3 days. The prevalence was 97% in newborns of 4-8 days. The way of parturition, laterality and time of pregnancy over 36 weeks hadn't any significant effect on the prevalence rate. The prevalence of females was higher than males. Quick screen was more sensitive than TEOAE. One ear of hearing loss was diagnosed after follow-up. CONCLUSION: The hearing screening test of newborns should be taken in hospitals after 4 days of birth, the way of parturition had no effect on the cochlear function. The mature time of cochlear hair cells was by the 36th week of pregnancy. Quick screen couldn't take place of TEOAE. Someone who had no TEOAE in one ear or two ears must be followed up and reexamined and exact diagnosis could be made as soon as possible combining with ABR.
Adult↗
[Effects of nutritional intervention on brain functions and its related biochemical indexes in mice exposed to high +Gy].
OBJECTIVE: To study the effects of nutritional intervention on changes of monoamines in rats brain, certain amino acids in rats serum and maze behaviors caused by high +Gy exposure. METHOD: The mice were arranged into control group (Group A), +Gy group (Group B) and +Gy nutritional intervention group (group C). Group A was not exposed to +Gy. Both Group B and group C were exposed to +10 Gy for 8 min. Three hours before +Gy exposure distilled water was given to mice in group B by gavage. The day before exposure pyridoxal fortified water was given and 3 h before exposure mixed amino acids solution were given by gavage to group C. Maze test scores were recorded for all groups. After the maze test was completed, blood was collected through the eyes for serum amino acids and brain tissue was collected by decollation for monoamines and gamma-glutamyl transferase (GGT) activity determinations. RESULT: After +Gy exposure maze test scores and brain NE concentrations decreased and abnormal behaviors were found. While other monoamine transmitters increased significantly. In group C maze behaviors improved and biochemical changes induced by +Gy exposure alleviated. CONCLUSION: High +Gy exposure can induce changes of neural transmitters coming from nutritional metabolites in central nervous system. As a result, brain functions are affected. Nutritional intervention can alleviate this negative effect to some extent.
Amino Acids↗
[Effect of Tauroursodeoxycholic acid on cytochrome C-mediated apoptosis in HepG2 cells].
OBJECTIVE: To investigate the effect of Tauroursodeoxycholic acid (TUDCA) on Taurodeoxycholic acid (TDCA)-induced HepG2 cell apoptosis and to clarify the molecular mechanism of its anti-apoptosis effect of TUDCA. METHODS: Morphologic evaluation of apoptotic cells was performed by Hoechst 33258 staining and electron microscope. DNA fragment was detected by electrophoresis on 1.5% agarose gels. Apoptosis rate was measured by flow cytometry using PI dye. Following incubation of HepG2 cells either with TDCA alone, or coincubation with TUDCA and TDCA, the releasing level of cytochrome c from mitochondria into cytosol was determined by western blot, also the activity of caspase-3, 8, 9. RESULTS: Incubating the cells with 400 micromol/L TDCA for 12 h induced the cells apoptosis significantly. The apoptotic rate decreased from 50.35% +/- 2.20% to 13.78% +/- 0.84% after coincubation with TUDCA, and this anti-apoptotic effect of TUDCA was confirmed by morphological and DNA ladder detection. TUDCA significantly inhibited the release of cytochrome C from mitochondria into cytosol, and the activity of caspase-9, 3 (t > or = 13.00, P < 0.01), especially at 12 h, caspase-3 activity decreased by 54.9% (t = 16.88, P < 0.01) and 52.5%, however it had no obvious effect on the activity of caspase-8 (t = 1.94, P > 0.05). CONCLUSIONS: TUDCA prevents HepG2 cells apoptosis induced by TDCA through modulating mitochondrial membrane stability, inhibiting the release of cytochrome c and the activation of procaspase-9 and 3. Anti-apoptotic mechanism of TUDCA may be considered to be one of the most important reasons that TUDCA exerts significant efficacy in the treatment of cholestatic liver diseases.
Apoptosis↗
[Dual cell seeding to improve cell retention on polytetrafluoroethylene grafts].
OBJECTIVE: To improve cell retention on the graft with dual cell seeding technique, adding a layer of smooth muscle cells (SMCs) between the graft and endothelial cells (ECs). METHODS: Polytetrafluoroethylene (PTFE) grafts pretreated with fibronectin were seeded with SMC followed by ECs one day later and exposure to an in vitro flow system. The number of ECs on grafts was counted under microscope. RESULTS: After exposure to the flow for 1 hour, 61% of the ECs lost when the ECs were seeded alone, whereas only 27% of the ECs lost when the ECs were seeded on the top of SMCs. Preconditioning of a cell seeded graft in a low rate flow did not improve cell retention when late exposure to a higher rate flow. CONCLUSION: This in vitro study indicates that using SMCs as a media layer between ECs and graft surface can improve the retention of seeded ECs on PTFE graft.
Blood Vessel Prosthesis↗
Effects of dietary supplementation of certain nutrients on maze performance and biochemical indices in mice after exposure to high +Gz.
OBJECTIVE: To explore the possible effects of nutritional supplements on brain function as reflected by Water Maze test performance in mice after +Gz exposure. METHOD: Mice were arranged into control group (group A), +Gz group without nutritional supplementation (group B) and +Gz plus nutritional supplementation group (group C). Each group contains 12 mice. Mice in group A were not exposed to +Gz while mice in both group B and group C were exposed to 8 min + 10 Gz. Distilled water was gavaged to group B mice 3 h before +Gz exposure. On the day before +Gz exposure pyridoxol fortified water was given and 3 h before exposure mixed amino acids solution were gavaged to group C mice. Water Maze test was done and scores were recorded in all groups. After the Water Maze test was completed, blood was collected through the eyes for serum amino acid determinations and brain tissue was collected by decollation for monoamine determination and gamma-glutamyl transferase (GGT) activity evaluation. RESULT: After +Gz exposure, longer completion time and more mistakes were observed in Water Maze test in group B as compared with group A and a trend of improvement in group C was noticed. The ratio of brain 5-HT to dopamine (DA) was significantly reduced in group C as compared with group B. Gamma glutamyl transferase (GGT) activity in brain tissue in group C and group B increased significantly. CONCLUSION: High sustained +Gz exposure significantly reduces Water Maze test performance in mice (longer completion time and more mistakes). It seems that there is a trend of improvement in Water Maze performance in mice in dietary nutritional supplementation group, which might be due to significant reduction in ratio of brain 5-HT to DA in mice with nutritional supplementation.
Amino Acids↗
[Detection of heterotrophic bacteria and vibrios in shoal of Bullacta exarata].
The number of heterotrophic bacteria and vibrios in shoal for Bullacta exarata rearing fluctuated mainly within 1.25 x 10(4)-7.21 x 10(4) cfu.g-1 and 0-1.08 x 10(4) cfu.g-1, respectively. 173 strains of bacteria, mainly belong to 13 genera were isolated. The predominant genera were composed of Bacillus, Photobacterium, Pseudomonas, Vibrio and some genera of Enterobacteriaceae. The number of bacteria changed in line with the alteration of the temperature, and was especially affected by the organic matter content after the use of pesticide. The predominant genera such as Bacillus were closely related with the environmental deterioration of rearing shoal.
Animals↗
[Restoring beta1 integrin activation function in K562 cells transfected with antisense VEGF121 cDNA].
To investigate the effect of vascular endothelial growth factor (VEGF) on beta1 integrin (VLA-4 and VLA-5) activation ability in K562 cells transfected with antisense VEGF121 cDNA, K562 cells were transfected with antisense (As), sense (S) and vector (V, pcDNA(3)). Flow cytometry was used to evaluate the expression rate of VLA-4 (CD49d/CD29) and VLA-5 (CD49e/CD29) and beta1 integrin activation ability in the transfected K562 cells. The results showed that the expression rates of VLA-4 and VLA-5 were more than 92% in the transfected K562 cells and there was no difference among the K562/V, K562/S and K562/As cells. However, beta1 integrin activated 9EG7 expression rate in K562/As cells was higher than that in K562/V cells [(75.6 +/- 10.5)% vs (41.2 +/- 2.1)%, P < 0.01)] after activation with beta1 integrin activator 8A2. It is concluded that function of beta1 integrin to be activated is restored in K562 cells transfected with antisense VEGF121 cDNA.
DNA↗
Effects of wild-type (Trp72) and mutant (Arg72) apolipoprotein(a) kringle IV-10 on the proliferation of human arterial smooth muscle cells.
OBJECTIVE: To assess the atherogenicity of lipoprotein(a), the effect of the heterogeneity of lysine binding of apolipoprotein(a) [apo(a)], a plasminogen-like glycoprotein component on the proliferation of human arterial smooth muscle cells (SMCs). METHODS: Both wild type (wt) Trp72 and mutant (mut) Trp72-->Arg forms of apo(a) kringle IV-10 were expressed by employing a GST-gene fusion system into E. coli. The proliferation of SMCs was determined by flow cytometry and MTT colorimetry. Enzyme-linked immunosorbent assay (ELISA) assay was used to detect the active form of transforming growth factor beta(1) (TGF-beta(1)). RESULTS: Apo(a) wt-kringle IV-10 that has lysine binding properties possessed a growth-stimulating activity to SMCs on a dose-dependence manner by stimulating cells in the G(1)/G(0) phase of cell cycle to S and G(2)/M phase, and reduced significantly the amounts of endogenous active TGF-beta(1) in culture when compared with the control medium and the GST group (2.4 +/- 0.5 vs 8.6 +/- 1.6 and 9.1 +/- 1.7 ng/ml, P < 0.01). The growth-stimulating effect of apo(a) mut-kringle IV-10 deficient in lysine binding was negligible. CONCLUSIONS: Apo(a) induces SMCs growth by inhibiting the activation of latent TGF-beta(1), an activity that may involve the ability of apo(a) kringle IV-10 to bind lysine. The mitogenic effect of apo(a) wt-kringle IV-10 on SMCs might play an active role in the atherogenic function of lipoprotein(a).
Apolipoproteins↗
[The apply of Cosmopost ceramic posts in clinic].
OBJECTIVE: To investigate the manufacture method and the effects of Cosmopost ceramic posts, to summarize the indications of Cosmopost ceramic post in clinic. METHODS: 228 pieces Cosmopost ceramic posts and cores were made for 96 patients. 2l7 pieces full ceramic crowns and 8 pieces full ceramic bridgs for Cosmopost ceramic posts and cores were made. The fitness of Cosmopost ceramic post were checked, and the color of all full ceramic crowns and full ceramic bridgs were checked in clinic. The amount of loosening and broken in all restorations were checked every year in clinic. follow up 2 - 3 years. RESULTS: 1 Cosmopost ceramic post was fracture about 1.5 mm before the full ceramic crown was worn. 227 pieces Cosmopost ceramic posts were perfect. All of the full ceramic crowns and bridgs for full ceramic posts were excellent in color. No loosening and broken cases were checked in 0.5 - 3 years. But the indications of Cosmopost ceramic posts were strict in clinic. CONCLUSION: Cosmopost ceramic post has natural aesthetic effect and good strength. it can be used in clinic.
Adolescent↗
[Changes of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 expressions on cultured rat mesangial cells transfected with Smad 7 vector].
OBJECTIVE: To investigate matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) expressions in the cultured rat mesangial cells (MsC) transfected with Smad 7 vector and to elucidate the mechanism of Smad 7 in blocking tissue fibrosis. METHODS: Lipofectin method was used to transfect Smad 7 vector into MsC. Western blot and RT-PCR analyses were then used to detect Smad 7 protein and mRNA expression levels. The expressions of MMP-2 and TIMP-2 were determined by Western blot, RT-PCR and zymography assay. RESULTS: Two MsC clones (S-22, S-26) with Smad 7 overexpression were successfully established. The two clones showed an increased expression of MMP-2 protein and enhanced enzyme activity. The expressions of TIMP-2 protein and mRNA however were suppressed. CONCLUSIONS: It is possible that Smad 7 can alleviate the development of tissue fibrosis by upregulating the expression of MMP-2 and downregulating the expression of TIMP-2 in mesangial cells.
Animals↗
[A case of pulmonary falciparum malaria complicated with hepatitis E].
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Adult↗
Direct determination of free amino acids and sugars in green tea by anion-exchange chromatography with integrated pulsed amperometric detection.
Determination of amino acids and sugars in green tea by anion-exchange chromatography with integrated pulsed amperometric detection was developed. Amino acids and sugars were separated on an anion-exchange column at a flow-rate of 0.25 ml/min by using ternary gradient elution consisting of deionized water, 0.25 M sodium hydroxide, and 1.0 M sodium acetate. Under optimized conditions, theanine was separated from glutamine and three sugars (glucose, fructose, and sucrose) were eluted earlier than the neutral amino acids to avoid their interference with each other. RSDs of the peak area of analytes were lower than 4.6%. Detection limits for the analytes ranged from 0.12 to 4.9 pmol. The linearities for all analytes were two or three orders of magnitude with the correlation coefficients greater than 0.99. This method was applied to determination of amino acids and sugars in green tea with satisfactory results.
Amino Acids↗
A single residue contributes sensitivity to allosteric modulation of AMPA receptors by LY395153.
Previous studies have shown that a single point mutation (S(750)Q) in the splice variant region of rat Glu(1) subunits can eliminate positive allosteric modulation by cyclothiazide. The present study investigated the effects of mutating the equivalent residue (S(776)Q) in the human Glu(4) subunit on the activity and binding of a novel AMPA receptor potentiator, LY395153 (N-2-(4-benzamidophenylpropyl-2-propanesulfonamide)). The mutation markedly attenuated, but did not eliminate, potentiation by LY395153 and cyclothiazide. In addition, binding of [3H]LY395153 was significantly reduced by this mutation. These effects occurred in the absence of any change in the response to glutamate or the binding of a competitive AMPA receptor antagonist, [3H]Ro 48-8587 ([2,4,5-3H]9-imidazol-1-yl-8-nitro-2,3,5,6-tetrahydro[1,2,4]-triazolo[1,5-c]quinazoline-2,5-dione triethylammonium salt). Collectively, these results demonstrate that structurally diverse classes of potentiators are sensitive to mutations of this single Ser residue, suggesting that binding to this residue may be necessary for positive allosteric modulation of AMPA receptors.
Allosteric Regulation↗
Simultaneous determination of amino acids and carbohydrates by anion-exchange chromatography with integrated pulsed amperometric detection.
A direct, sensitive, simple and practical method for simultaneous determination of amino acids and carbohydrates by anion-exchange chromatography with integrated pulsed amperometric detection was developed. The retention behavior of amino acids and carbohydrates on the anion-exchange column and the detection of amino acids and carbohydrates at different integrated pulsed amperometric detection waveforms were investigated. The optimized gradient eluent conditions for analysis of 17 amino acids and nine carbohydrates were obtained. Separation time was 100 min. Detection limits for amino acids and carbohydrates were 5.2-207.1 nM under injection volume of 25 microl. The RSDs of peak area were 1.2-3.3%. The calibration graphs of peak area for the analytes were linear over about three orders of magnitude with a correlation coefficient of 0.9950-0.9999. The method was applied to determine amino acids and carbohydrates in a liquid condiment with satisfactory results.
Amino Acids↗
A role for the melanocortin 4 receptor in sexual function.
By using a combination of genetic, pharmacological, and anatomical approaches, we show that the melanocortin 4 receptor (MC4R), implicated in the control of food intake and energy expenditure, also modulates erectile function and sexual behavior. Evidence supporting this notion is based on several findings: (i) a highly selective non-peptide MC4R agonist augments erectile activity initiated by electrical stimulation of the cavernous nerve in wild-type but not Mc4r-null mice; (ii) copulatory behavior is enhanced by administration of a selective MC4R agonist and is diminished in mice lacking Mc4r; (iii) reverse transcription (RT)-PCR and non-PCR based methods demonstrate MC4R expression in rat and human penis, and rat spinal cord, hypothalamus, brainstem, pelvic ganglion (major autonomic relay center to the penis), but not in rat primary corpus smooth muscle cavernosum cells; and (iv) in situ hybridization of glans tissue from the human and rat penis reveal MC4R expression in nerve fibers and mechanoreceptors in the glans of the penis. Collectively, these data implicate the MC4R in the modulation of penile erectile function and provide evidence that MC4R-mediated proerectile responses may be activated through neuronal circuitry in spinal cord erectile centers and somatosensory afferent nerve terminals of the penis. Our results provide a basis for the existence of MC4R-controlled neuronal pathways that control sexual function.
Animals↗
PTEN, but not SHIP and SHIP2, suppresses the PI3K/Akt pathway and induces growth inhibition and apoptosis of myeloma cells.
Expression of PTEN tumor suppressor gene has been known to dephosphorylate the phosphatidylinositol 3' kinase (PI3K) products on the 3 prime inositol ring, resulting in reduced Akt activation. Loss of PTEN expression in OPM2 and delta47 human myeloma lines led to high Akt activity toward insulin-like growth factor I (IGF-I). In contrast, mouse plasma cell tumor (PCT) lines, expressing wild type PTEN, did not respond to IGF-I for Akt activation. We demonstrated here that endogenous PTEN played a negative role in controlling Akt activity in both mouse PCT and NIH3T3 fibroblast lines by using anti-sense oligonucleotides against PTEN. To determine the role of src-homology 2-containing inositol 5' phosphatase (SHIP) in regulating the PI3K/Akt pathway, we manipulated its expression by down-regulation and overexpression in myeloma, PCT and NIH3T3 lines and analysed Akt activation. Our results showed that SHIP, unlike PTEN, did not affect Akt activity in all systems analysed, despite its ability to dephosphorylate a PI3K product. Although SHIP2 expression resulted in suppression of interleukin-6-mediated mitogen-activated protein kinase activation, expression of SHIP and SHIP2 in a PTEN-null myeloma line did not suppress Akt activity. Biologically, expression of only PTEN, but not SHIP and SHIP2, resulted in growth inhibition and increased apoptosis in OPM2 myeloma line. Together, our results have established the role of PTEN, but not SHIP and SHIP2, in negatively regulating the PI3K/Akt cascade and in myeloma leukemogenesis.
3T3 Cells↗
Mutational analysis of HIV-1 long terminal repeats to explore the relative contribution of reverse transcriptase and RNA polymerase II to viral mutagenesis.
HIV-1 evolves rapidly, which is thought to result from one or more error-prone steps in the virus life cycle. Because HIV-1 reverse transcriptase (RT) does not possess 3'- to 5'-exonucleolytic proofreading activity and because RT has been shown to be error-prone in cell free systems, it should be an important contributor to the high rate of HIV-1 mutation. However, because RNA polymerase II (pol II) synthesizes viral RNA, it might also contribute significantly to HIV-1 mutagenesis. To assess the relative contributions of RT and RNA pol II to HIV-1 mutagenesis, a system was established to study the rate and nature of mutations in HIV-1 long terminal repeats (LTRs). Owing to the unique nature of replication at the ends of the viral genome, mutational analysis of retroviral LTRs provides an opportunity to evaluate the relative contribution of HIV-1 RT and RNA pol II to viral mutagenesis. Mutational analysis was performed on both LTRs of 215 proviruses, restricted to a single cycle of replication, employing single-stranded conformational polymorphism and DNA sequencing allowing direct identification of mutations in the absence of selection and within autologous viral sequences. A total of 21 independent mutations was identified. Ten mutations were observed in both LTRs, which could have been introduced by either RT or RNA pol II, whereas the other eleven mutations were only present in a single LTR and could only have been introduced by RT. This provides the first direct evidence that HIV-1 RT contributes significantly to HIV-1 mutagenesis and is likely to be the primary engine for HIV-1 mutagenesis. Moreover, mutations were observed at the U3-R border, but the nature of the mutations and their frequency differed from experiments performed using cell-free systems suggesting that other viral and/or cellular factors contribute to fidelity at the ends of the viral genome.
Base Sequence↗