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Biomedical subjects

J You

Publications and source records attributed to J You.

At least 37 records · Page 2Linked to original sources
PubMed2001

Neuropeptide Y-mediated constriction and dilation in rat middle cerebral arteries.

Neuropeptide Y (NPY) is an important vasoconstrictor in the cerebral circulation. Its constrictor response is because of activation of NPY receptors on the vascular smooth muscle (VSM). Little is known regarding the effects of NPY on the endothelium. In the current study, the authors tested the hypothesis that NPY can either constrict or dilate rat middle cerebral arteries (MCAs). Constriction is elicited by stimulating receptors on the VSM; dilation is elicited by stimulating receptors on the endothelium. Middle cerebral arteries were isolated, cannulated with micropipettes, pressurized to 85 mm Hg, and luminally perfused. The extraluminal application of NPY (mixed agonist), [Leu31, Pro34]-NPY (Y1 agonist), or NPY-[13-36] (Y2 agonist) produced concentration-dependent constrictions. BIBP 3226 (Y1 selective antagonist) significantly attenuated the NPY- and [Leu31, Pro34]-NPY-induced constrictions. The luminal application of NPY, [Leu31, Pro34]-NPY, and NPY-[13-36] produced concentration-dependent dilations of MCAs. The maximum dilation produced by the NPY receptor agonists was approximately 40% of the dilation elicited by the luminal administration of 10(-5) mol/L ATP. Dilations elicited by luminal NPY, [Leu31, Pro34]-NPY, or NPY-[13-36] were abolished by inhibition of nitric oxide synthase with 10(-5) mol/L Nomega-nitro-L-arginine methyl ester (L-NAME) or removal of the endothelium. Dilations produced by luminal NPY or luminal [Leu31, Pro34]-NPY were not affected by BIBP 3226. Stimulation of NPY receptors on vascular smooth muscle constricted MCAs. Stimulation of an NPY receptor other than the Y1 subtype on endothelium dilated the MCAs by releasing nitric oxide.

Animals↗
PubMed2001

Gap junctions and fluid flow response in MC3T3-E1 cells.

In the current study, we examined the role of gap junctions in oscillatory fluid flow-induced changes in intracellular Ca(2+) concentration and prostaglandin release in osteoblastic cells. This work was completed in MC3T3-E1 cells with intact gap junctional communication as well as in MC3T3-E1 cells rendered communication deficient through expression of a dominant-negative connexin. Our results demonstrate that MC3T3-E1 cells with intact gap junctions respond to oscillatory fluid flow with significant increases in prostaglandin E(2) (PGE(2)) release, whereas cells with diminished gap junctional communication do not. Furthermore, we found that cytosolic Ca(2+) (Ca) response was unaltered by the disruption in gap junctional communication and was not significantly different among the cell lines. Thus our results suggest that gap junctions contribute to the PGE(2) but not to the Ca response to oscillatory fluid flow. These findings implicate gap junctional intercellular communication (GJIC) in bone cell ensemble responsiveness to oscillatory fluid flow and suggest that gap junctions and GJIC play a pivotal role in mechanotransduction mechanisms in bone.

Animals↗
PubMed2001

Identification of metastasis associated gene G3BP by differential display in human cancer cell sublines with different metastatic potentials G3BP as highly expressed in non-metastatic.

OBJECTIVE: To investigate genes involved in cancer metastasis, mRNA differential display was used to compare the levels of gene expression in two cell sublines derived from human giant cell carcinoma of lung (PG) which had different metastatic potentials. METHODS: Using in vivo tumorigenicity and a spontaneous metastasis assay in nude mice, two sublines (BE1, LH7) from human giant cell carcinoma of lung (PG) with different metastatic potentials were isolated and characterized. mRNA differential display was used to compare the levels of gene expression between them and the obtained results were confirmed by Northern hybridization. RESULTS: One differentially expressed band was nearly identical (99% homology) to Ras-GTPase-Activating protein SH3 domain binding protein (G3BP). G3BP displayed a strong expression in LH7 (non-metastatic in recipient nude mice) and a very weak expression in BE1 (100% metastatic frequency). The same different expression level of G3BP was detected in Northern hybridization with another panel of cell sublines with different metastatic potentials (established in our lab) derived from human prostate carcinoma cell line PC-3M. CONCLUSION: Our results indicate that G3BP was implicated in cancer metastasis because of its differential expressions in the two panels of cell sublines with different metastatic potentials.

Animals↗
PubMed2001

[Activation of p38 and c-Jun NH2-terminal kinase mitogen-activated protein kinases in human prostate carcinoma cell lines with different metastatic potentials].

OBJECTIVE: To investigate the influence of P2 purinoceptor agonist ATP on p38 mitogen-activated protein kinases (MAPK) and JNK (c-Jun NH(2)-terminal kinase) signaling pathway in two human prostate cancer cell sublines (1E8 and 2B4) with different metastasis potentials. METHODS: Activated p38 and JNK were detected by Western blot with phospho-specific antibodies directed against the dually phosphorylated active forms of p38 or JNK. RESULTS: Exposure of 1E8 and 2B4 prostate cancer cells to ATP resulted in p38 activation in a concentration- and time-dependent manner. ATP-induced p38 activities were higher in metastatic 1E8 cells when compared with nonmetastatic 2B4 cells. JNK signaling pathway was not activated by ATP. An MEK inhibitor PD 98059 failed to inhibit ATP-induced p38 activation, while p38 inhibitor SB 203580 and P2 purinoceptor antagonist suramin effectively inhibited activation of p38, the inhibition rate being 1E8 83% and 79%, 2B4 81% and 69%. The response of ATP-stimulated p38 to G-protein modulator pertussis toxin in 1E8 and 2B4 cells was not obvious. CONCLUSIONS: p38 but not JNK signaling pathway can be activated by P2 purinoceptor agonist ATP. Differences of p38 activation by ATP are noted between metastatic 1E8 cells and non-metastatic 2B4 cells. These results provide instructive clues to cancer malignant growth and metastasis research.

Adenosine Triphosphate↗
PubMed2001

[Supercritical fluid extraction of beta-elemene under lower pressure].

A method has been developed for the extraction and analysis of the active component beta-elemene from Rhizoma Atractylodis Macrocephalae by supercritical fluid extraction with CO2 containing ethanol. The article discusses some factors such as pressure, temperature and modifier that affect the selectivity. Class-selective extraction has been performed by varying the pressure. beta-Elemene could almost be extracted completely at lower pressure (12.0 MPa) and its relative amount was raised from 4.8% under higher pressure to 8.0% for lower pressure.

Atractylodes↗
PubMed2001

[Advances in the fiber coating of solid phase micro-extraction].

Solid phase micro-extraction (SPME) is a simple and effective sample preparation technique and fiber coatings play a very important role in SPME process. The discussion begins with a brief historical perspective from the very early work conducted almost a decade ago. At the moment, more than 20 alternatives of fiber coatings and size are available. In this paper, the coatings are divided into two categories: commercial fibers and custom-made fibers. A novel so-gel method has been introduced for the preparation of the coatings.

Adsorption↗
PubMed2001

[Selective isolation of anethole from volatile oil of Foeniculum vulgare Mill by inclusion crystalline with chela-shape host].

AIM: To isolate the components from the volatile oil of Foeniculum vulgare Mill. METHODS: According to the function of molecular recognition of supramolecular chemistry, chela shape molecule, trans-1, 2-biphenyl-1, 2-acenaphthendiol was used as host molecule and the volatile oil of Foeniculum vulgare Mill as guest molecule. Trans-1, 2-biphenyl-1, 2-acenaphthendiol can recognize the components that endowed with interactional complementarity and form inclusion compound as crystals. RESULTS: The anethole in the volatile oil was selectively included as trans-1,2-biphenyl-1,2-acenaphthendiol which was obtained in pure state from the inclusion compound by Kugelrohr vacuum technology. The formation of inclusion compound was confirmed by means of IR and powder XRD. The structure of the selectively isolated component was elucidated as trans-anethole by means of IR, 1HMMR and MS. CONCLUSION: The experimental results showed that the method is simple, rapid and selective for isolation anethole from volatile oil of Foeniculum vulgare Mill.

Allylbenzene Derivatives↗
PubMed2000

Activation of the IkappaB kinase complex by TRAF6 requires a dimeric ubiquitin-conjugating enzyme complex and a unique polyubiquitin chain.

TRAF6 is a signal transducer in the NF-kappaB pathway that activates IkappaB kinase (IKK) in response to proinflammatory cytokines. We have purified a heterodimeric protein complex that links TRAF6 to IKK activation. Peptide mass fingerprinting analysis reveals that this complex is composed of the ubiquitin conjugating enzyme Ubc13 and the Ubc-like protein Uev1A. We find that TRAF6, a RING domain protein, functions together with Ubc13/Uev1A to catalyze the synthesis of unique polyubiquitin chains linked through lysine-63 (K63) of ubiquitin. Blockade of this polyubiquitin chain synthesis, but not inhibition of the proteasome, prevents the activation of IKK by TRAF6. These results unveil a new regulatory function for ubiquitin, in which IKK is activated through the assembly of K63-linked polyubiquitin chains.

Amino Acid Sequence↗
PubMed2000

Electronic and vibrational spectra of a series of substituted carbazole derivatives.

The FTIR and FTR spectra of halogen (Cl, Br, I) substituted carbazole and their N-acetic and propionic acids have been recorded. A number of lines have been assigned on the basis of previous studies on the parent compound and by comparisons with the characteristic vibrations of their constituent structural units as well as comparing the spectra from FTIR and FTR. Some substituent-sensitive bands and characteristic bands were found. The electronic absorption spectra of these compounds in acetonitrile were also measured and are briefly discussed.

Carbazoles↗
PubMed2000

Substrate deformation levels associated with routine physical activity are less stimulatory to bone cells relative to loading-induced oscillatory fluid flow.

Although it is well accepted that bone tissue metabolism is regulated by external mechanical loads, it remains unclear to what load-induced physical signals bone cells respond. In this study, a novel computer-controlled stretch device and parallel plate flow chamber were employed to investigate cytosolic calcium (Ca2+i) mobilization in response to a range of dynamic substrate strain levels (0.1-10 percent, 1 Hz) and oscillating fluid flow (2 N/m2, 1 Hz). In addition, we quantified the effect of dynamic substrate strain and oscillating fluid flow on the expression of mRNA for the bone matrix protein osteopontin (OPN). Our data demonstrate that continuum strain levels observed for routine physical activities (< 0.5 percent) do not induce Ca2+i responses in osteoblastic cells in vitro. However, there was a significant increase in the number of responding cells at larger strain levels. Moreover, we found no change in osteopontin mRNA level in response to 0.5 percent strain at 1 Hz. In contrast, oscillating fluid flow predicted to occur in the lacunar-canalicular system due to routine physical activities (2 N/m2, 1 Hz) caused significant increases in both Ca2+i and OPN mRNA. These data suggest that, relative to fluid flow, substrate deformation may play less of a role in bone cell mechanotransduction associated with bone adaptation to routine loads.

Animals↗
PubMed2000

[Clinical and experimental study on treatment of infantile autumn diarrhea by retention enema with Qilian liquid].

OBJECTIVE: To find out the effective treatment for infantile autumn diarrhea (IAD). METHODS: Retention enema with Qilian Liquid (QLL) was applied to the patients of IAD with positive antigen of rotavirus in stool, and the clinical effect in the treated group was compared with that in the control group in aspects of negative conversion rate of rotavirus and change of immunoglobulin. Animal experimental study was also conducted. RESULTS: The disappearance time of principal symptoms, negative conversion rate of rotavirus and serum levels of IgA and IgG in the treated group were significantly higher than those in the control group (P < 0.01, P < 0.05). Experimental study showed that QLL not only has the the anti-viral effects to stop diarrhea, but also has effects in enhancing immune function and protecting intestinal mucous membrane. CONCLUSION: Retention enema with QLL is an effective therapy for the treatment of IAD.

Administration, Rectal↗
PubMed2000

[The effects of cyclin E on the growth and other cell cycle related genes of breast carcinoma cells MCF-7].

OBJECTIVE: To investigate the effects of cyclin E in high and low expression on the cell growth and other cell cycle associated genes of MCF-7 cells. METHODS: Eukaryotic expression vehicles of sense and antisense cyclin E were constructed and transferred into the MCF-7 cell line using lipofectAMINE. The integration and expression of cyclin E were conformed by Southern and Western blot. The cells growth was observed and the changes in cell cycle were analyzed by flow cytometry. The expression of other cell cycle associated genes was assayed using Western blot. RESULTS: A high expression of cyclin E enabled to promote the cell growth and DNA synthesis and accelerated the proceeding of G(1) phase to S phase, It also promoted the phosphorylatin of pRB and up-regulate the expression of p27 while a low expression of cyclin E showed an opposite effect. CONCLUSION: Different expression of cyclin E enables to affect growth of MCF-7 cell by the changes of cell cycle related genes.

Breast Neoplasms↗
PubMed2000

[Effect of mouse p53 minigene on lung cancer cells with different 172 structures regulated by tetracycline].

OBJECTIVE: To investigate the effect of mouse 172 wild-type p53 (Arg), pseudo-wild-mutant-type p53 (Arg-->Leu) and mutant-type p53 (Arg-->His) induced by absence of tetracycline on the growth of PG cell line. METHODS: Three variant types of p53 minigene were sub-cloned by gene recombination into an expression vector which was controlled by tetracycline. Through LipofectAMINE, the vectors were transfected into p53 defective PG (248CGG-->CTT) cells, and the transfectants were screened in the selecting medium containing puromycin. Tumor suppressing effects were studied by MTT absorption, flow cytometry and Western blotting. RESULTS: Wild-type p53 and pseudo-wild-mutant-type p53 could lead cells to decrease their growth rates, arrest cell cycle and transactivation of p21(WAF1). Mutant-type p53 was defective in tumor suppression. CONCLUSION: Wild-type p53 and pseudo-wild-type p53 may inhibit cell growth and induce cell cycle arrest. Some p53 variants such as 172 Arg-->Leu can still retain the tumor suppression function of the wild-type.

Amino Acid Substitution↗
PubMed2000

[Inhibition of growth and metastasis of human giant cell carcinoma of the lung by transfection of antisense VEGF121 cDNA].

OBJECTIVE: To explore the effects of blocking the VEGF/VEGF receptor paracrine pathway on growth and metastasis of human lung carcinoma cell line PG and to evaluate its potential application in gene therapy of cancer. METHODS: The eukaryotic expression vectors bearing either sense-VEGF121 cDNA or antisense-VEGF121 cDNA was constructed and transfected into PG cells. In vitro and in vivo tests such as Northern blotting hybridization, Western blotting immunochemistry analysis, as well as xenografting in nude mice were used to analyze the effect of antisense-VEGF. RESULTS: The transfectants stably expressing antisense VEGF121 were observed to produce markedly reduced 3.3 kb VEGF mRNA and 45 KD, 41 KD, 32KD VEGF proteins. When xenografted s.c. into nude mice, growth and metastasis of the antisense-VEGF transfected cell lines were greatly inhibited when compared with control cells. CONCLUSION: Antisense VEGF gene significantly inhibited tumor growth and metastasis and may provide an experimental example for the development of antiangiogenic gene therapy.

Animals↗
PubMed2000

[High temperature Raman spectroscopic study of the structure of sodium disilicate crystal, glass and its melt].

The structure of Na2Si2O5 from room temperature up to 1,773 K are studied by high temperature Raman spectroscopy using copper vapor pulse laser and integral time-resolved detection technique without any black-body radiation effect on spectral record. Back-scattering optical configuration is coupled with confocal collection of Raman signal of macro-sample in the high temperature shaft tube furnace. Results show that temperature-dependent Raman spectra can clearly indicate phase transition during melting. Relative densities of various kinds of SiO4(n-4) (n, bridging-oxygen number binding to one tetrahedron former Si) tetrahedrons can be qualitatively and quantitatively resolved by Gaussian spectral deconvolution. Obviously high temperature Raman spectroscopy provides an useful tool for the micro-structure research of materials under high temperature.

Crystallization↗
PubMed2000

[High temperature Raman spectra and micro-structure study of lithium metaborate and its melt].

Lithium metaborate (LiBO2) is studied by high temperature Raman spectroscopy from room temperature up to 1,673 K, and spectra drawing in different temperature are got. By analyzing, it focus on the phase transition, it is that the endless chains of BO3 triangles transform into rings of (B3O6)3- at about 1,123 K, and then the different kind of phase balance's motion occurs after 1,273 K which implies that both endless chain and ring have changed to CRN. In the drawing, the variation of peak's area rate implies the micro-structure information, and shows the process from order to disorder.

English Abstract↗