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N Liu

Publications and source records attributed to N Liu.

At least 55 records · Page 3Linked to original sources
PubMed2001

Initial investigations of 99mTc-labeled morpholinos for radiopharmaceutical applications.

This laboratory is evaluating phosphorothioate deoxyribonucleic acids (DNAs) and peptide nucleic acids (PNAs) for a variety of nuclear medicine applications. Morpholinos (MORFs) are a new class of oligomers with a nuclease-resistant, nonionic and water-soluble phosphorodiamidate backbone. We now report on the in vitro and in vivo properties of MORFs labeled with technetium-99m. Both 15-mer and 18-mer MORFs were obtained, each with a primary amine attached to the 3' equivalent end via a three-carbon beta-alanine linker. The amine was used to conjugate with NHS-MAG3 for 99mTc radiolabeling. By surface plasmon resonance at room temperature, the association rate constant for hybridization of the 18-mer MORF to its complementary oligomer (cMORF) was equivalent to that of DNAs and PNAs of comparable length. Hybridization of 99mTc-MORF in vitro to free cMORF, to a cMORF polymer and to cMORF beads was nearly quantitative under a variety of conditions. Kinetic studies in vitro at room temperature showed rapid (2-5 min) and nearly quantitative (90%) binding to cMORF beads. Using size-exclusion high-performance liquid chromatography, the stability of the 99mTc-MORF was found to be greater than 85% over 24 h in 37 degrees C serum with minimal protein binding. In normal mice, the 99mTc-MORF showed rapid pharmacokinetics, with only 21% and 8% remaining in the whole body at 3 and 24 h post administration, respectively. In vivo targeting with 99mTc-MORF of cMORF beads in one thigh of normal mice compared to control beads in the other thigh showed target/control thigh ratios of 2-10 between 3 and 24 h. These results demonstrate that MORF oligomers are capable of in vivo hybridization. Their properties of hybridization affinity and kinetics and their in vivo stability and pharmacokinetics make them suitable subjects for in vivo studies.

Animals↗
PubMed2001

Identification of an 85-kb DNA fragment containing pms1, a locus for photoperiod-sensitive genic male sterility in rice.

Photoperiod-sensitive genic male-sterile rice has a number of desirable characteristics for hybrid rice production. Previous studies identified pms1, located on chromosome 7, as a major locus for photoperiod-sensitive genic male sterility. The objective of this study was to localize the pms1 locus to a specific DNA fragment by genetic and physical mapping. Using 240 highly sterile individuals and a random sample of 599 individuals from an F2 population of over 5000 individuals from a cross between Minghui 63 and 32001S, we localized the pms1 locus by molecular marker analysis to a genetic interval of about 4 cM, 0.25 cM from RG477 on one side and 3.8 cM from R1807 on the other side. A contig map composed of seven BAC clones spanning approximate 500 kb in length was constructed for the pms1 region by screening a BAC library of Minghui 63 DNA using RFLP markers and chromosomal walking. Analysis of recombination events in the pms1 region among the highly sterile individuals reduced the length of the contig map to three BAC clones. Sequencing of one BAC clone, 2109, identified two SSR markers located 85 kb apart in the clone that flanked the pms1 locus on both sides, as indicated by the distribution of recombination events. We thus concluded that the pms1 locus was located on the fragment bounded by the two SSR markers.

Chromosome Mapping↗
PubMed2001

A novel and simplified route to the synthesis of N3S chelators for 99mTc labeling.

As one example of a N(3)S chelator, MAG(3) has been used successfully for labeling peptides, proteins, DNAs and other carriers with 99mTc. We now report on a simplified route to the synthesis of N(3)S chelators. As a test of the approach, we have synthesized the succinimidyl ester of S-acetylmercaptoacetyl-(L)-glutamyl(gamma-O-t-Bu)glycylglycolic acid (MAGluG(2)) (thus MAG(3) with a t-butyl protected carboxyl group on the backbone via an ethylene linker) and the succinimidyl ester of S-acetylmercaptoacetyl-phenylalanyl-glycylglycolic acid (MAPheG(2)) (thus MAG(3) with a benzyl group on the backbone). The first chelator was selected to provide a free carboxyl group in the backbone after conjugation to peptides and after t-butyl deprotection whereas the second chelator was selected for its expected lipophilicity. The Fmoc protected NHS ester of the corresponding glutamic acid and phenylalanine were purchased and each was reacted with diglycine followed by Fmoc deprotection to provide the tripeptide. This was reacted with SATA and the NHS ester added via DCC to provide the final NHS ester of MAGluG(2) or MAPheG(2). After purification, both NHS-derivatives were conjugated to HNE2 (a 7 kDa neutrophil elastase inhibitor) as a test polypeptide. In the MAGluG(2) case, t-butyl deprotection was performed after peptide conjugation. Both of the conjugated HNE2 peptides were radiolabeled with 99mTc by transchelation from tartrate as is routine for the labeling of MAG(3)-conjugated carriers. Labeling efficiencies and stability of the chelated 99mTc towards cysteine transchelation were identical for HNE2 labeled via MAGluG(2), MAPheG(2) and MAG(3). A 3 hr biodistribution of 99mTc radiolabels in normal mice showed significant differences between the three labeled HNE2, especially in major organs (liver and kidneys). We conclude that this synthesis route provides a simplified path to the synthesis of N(3)S chelators which in principle may be used to incorporate any natural or unnatural amino acid.

Animals↗
PubMed2001

Coagulation process proceeds on cultured human mesangial cells via expression of factor V.

BACKGROUND: In a previous clinicopathological study, we observed mesangial factor V expression accompanied by the intact form of cross-linked fibrin deposition in the active type of IgA nephropathy. The conversion of prothrombin to thrombin by factor Xa is potently accelerated more than 104-fold by the presence of factor V, which is a membrane-bound cofactor. Another membrane-bound cofactor, tissue factor, is known to play an initiating role in the coagulation cascade and to be synthesized in mesangial cells (MCs) by the stimulation of tumor necrosis factor-alpha (TNF-alpha). However, the synthesis of factor V, which plays on the terminating stage of prothrombin activation, has not been reported previously in MCs by in vitro study. Our current study tested the coagulation process via expression of factor V by the stimulation of proinflammatory cytokine, TNF-alpha, in cultured human MCs. METHODS: To evaluate factor V protein expression, immunoperoxidase staining with densitometric evaluation and Western blot analysis were conducted after stimulation of TNF-alpha. To test factor V activity, stimulated MCs were incubated in combination with factor Xa, prothrombin, fibrinogen and factor XIII, and fibrin production on MCs was assessed after immunoperoxidase staining on the cell surface. In a blocking test using an antibody against factor V, suppression of fibrin production was evaluated to clarify the role of factor V activity. For the evaluation of factor V mRNA expression in cultured human MCs, in situ hybridization and Northern blot analysis were performed. RESULTS: Factor V protein expression in MCs after TNF-alpha stimulation increased both time- and dose-dependently. As a marker of factor V activity with exogenous factor Xa, fibrin production on TNF-alpha-stimulated MCs was increased in a time-dependent manner and was inhibited by the addition of anti-factor V antibody. Factor V mRNA was identified in MCs by in situ hybridization and showed an increase after stimulation with TNF-alpha on Northern blot analysis. CONCLUSIONS: Our data suggest that the coagulation process proceeds on MCs as the result of increased expression of endogenous factor V activity on its cell surface in cooperation with exogenous factor Xa.

Antibodies↗
PubMed2001

Hepatocyte growth factor is predominantly expressed by the carcinoma cells in non-small-cell lung cancer.

Hepatocyte growth factor (HGF) exerts multifunctional regulatory roles in the growth, morphogenesis, differentiation, and motility of epithelial cells, and putatively plays important roles in tumor angiogenesis and metastasis. Aside from the full-length protein, 2 naturally occurring truncated HGF isoforms (NK1 and NK2) have been identified. Recent evidence suggests that a high level of HGF in surgically resected non-small-cell lung carcinoma (NSCLC) is a negative prognostic marker for NSCLC patients' survival. The origin of HGF in these tumors remains uncertain. We show here by in situ hybridization and immunohistochemistry that HGF messenger RNA (mRNA) and protein were predominantly expressed by the tumor cells in a high percentage of primary NSCLC. Stromal cell expression of HGF was limited to some lymphocytes and endothelial cells. Normal bronchial and bronchiolar epithelial cells also expressed HGF mRNA and immunoreactive protein. The mRNA transcripts and putative proteins of all 3 known HGF isoforms were detected in both normal lung and lung cancer tissues, but the full-length HGF was predominantly expressed. Our findings indicate that both autocrine and paracrine functions of HGF are likely to contribute to the pathobiology of lung cancer in vivo.

Adenocarcinoma↗
PubMed2001

The XRCC2 human repair gene influences recombinational rearrangements leading to chromatid breaks.

PURPOSE: To test the possible involvement of the XRCC2 gene in the control of intra- versus interchromatid rearrangements leading to chromatid breaks in G2 cells by studying the colour-switch ratio (CSR) in harlequin-stained Chinese hamster irs1 cells. MATERIALS AND METHODS: The V79-4 mutant cell lines irs1 (XRCC2 mutation) and irs2 (XRCC8 mutation), two WT V79 lines and GT621-1 (irs1 transfected with the XRCC2 gene) were labelled with BrdU through two cell cycles, irradiated and sampled 1.5h after exposure. Metaphase spreads were analysed for chromatid break frequency and frequencies of colour-switch (colour-switch between chromatids at the break point) and non-colour-switch breaks, from which the CSR was calculated. RESULTS: Chromatid breaks were induced linearly with dose in all lines, and frequencies were elevated in irs1 and irs2 mutant cell lines when compared with WT lines. An XRCC2 transfected line (GT621-1) showed full radiosensitivity complementation with respect to frequencies of chromatid breaks. The CSR was significantly higher in irs1 (13.9%) than in the parental V79-4 (7.5%) or irs2 (4.9%) cells. GT621-1 cells showed partial, but significant complementation with respect to CSR (9.2%). CONCLUSIONS: It is concluded that the significantly higher CSR for the irs1 mutant than for the wild-type parental V79-4 line indicates the involvement of the XRCC2 gene product in the control of the rearrangement process leading to chromatid breaks.

Animals↗
PubMed2001

Cationic liposomes enhance cellular/nuclear localization of 99mTc-antisense oligonucleotides in target tumor cells.

UNLABELLED: Efforts are underway to apply strategies developed in connection with antisense chemotherapy to antisense imaging in nuclear medicine. One such strategy is the use of cationic liposome to enhance the cellular uptake of antisense oligonucleotides. METHODS: Using a 99mTc-labeled 18-mer uniformly phosphorothioate DNA antisense to the mRNA of the RI alpha subunit of PKA, the effects of a cationic liposome as carrier on cell uptake and efflux kinetics in tissue culture was evaluated in a RI alpha mRNA positive ACHN cell line. The sense DNA was used as control. RESULTS: Cell uptake was increased 4-5 fold using the liposome carrier compared to the same dosage of naked DNA. Whether naked or liposome-bound, the antisense DNA showed slower efflux from cells compared to the control, resulting in statistically higher accumulation of the antisense compared to the control DNA and suggesting an antisense effect. The internalization and increased cellular accumulation for both antisense and control DNAs with liposomes were demonstrated by microautoradiography and by subcellular fractionation. Finally, using 99mTc-labeled 15-mer antisense DNA against the c-myc oncogene mRNA in MDA-MB-231 cells, significantly more radiolabel was found in total mRNA for the antisense compared to the sense control DNA, both with and without liposome carrier. In conclusion, in tissue culture, the use of a cationic liposome carrier greatly increased cellular uptake and target mRNA binding of 99mTc-labeled antisense DNA.

Autoradiography↗
PubMed2001

The ataxia-telangiectasia gene product may modulate DNA turnover and control cell fate by regulating cellular redox in lymphocytes.

The ATM kinase, when activated postnatally, exerts multiple functions to prevent the onset of ataxia-telangiectasia (AT). Using freshly isolated thymocytes from Atm-/- mice that were under stress during postnatal differentiation, we noted that thiol redox activity, as indicated by reduction of the tetrazolium MTS, and DNA turnover activity, as indicated by incorporation of [(3)H]thymidine into DNA, were both greatly increased compared with activities in thymocytes from Atm+/+ mice. This increased thymidine incorporation could be suppressed by the thiol N-acetylcysteine. In primary noncycling splenocytes, mitogens proportionally increased both the rate of [(3)H]thymidine incorporation and the rate of reduction of MTS. The mitogen-induced activities in splenocytes were not affected by ATM but were suppressed by the calcineurin-dependent inhibitor FK-506, which has no effect on these activities in thymocytes. These findings suggest that increased [(3)H]thymidine incorporation and reducing power indicate increased cell cycling in mitogenically stimulated splenocytes, whereas these two indicators represent increased FK-506-independent DNA turnover activities in thymocytes. Thus, a primary function of ATM is to activate the redox-sensitive checkpoint required for down-regulation of DNA turnover activities in developing lymphocytes. Cell-cycling checkpoints in undamaged quiescent lymphocytes are not activated by ATM with mitogenic stimulation. ATM may suppress abnormal DNA turnover and the resultant oncogenesis by regulating cellular thiol redox pathways.

Acetylcysteine↗
PubMed2001

Extracellular matrix protein 1 (ECM1) has angiogenic properties and is expressed by breast tumor cells.

Tumor growth and metastasis are critically dependent on the formation of new blood vessels. The present study found that extracellular matrix protein 1 (ECM1), a newly described secretory glycoprotein, promotes angiogenesis. This was initially suggested by in situ hybridization studies of mouse embryos indicating that the ECM1 message was associated with blood vessels and its expression pattern was similar to that of flk-1, a recognized marker for endothelium. More direct evidence for the role of ECM1 in angiogenesis was provided by the fact that highly purified recombinant ECM1 stimulated the proliferation of cultured endothelial cells and promoted blood vessel formation in the chorioallantoic membrane of chicken embryos. Immunohistochemical staining with specific antibodies indicated that ECM1 was expressed by the human breast cancer cell lines MDA-435 and LCC15, both of which are highly tumorigenic. In addition, staining of tissue sections from patients with breast cancer revealed that ECM1 was present in a significant proportion of primary and secondary tumors. Collectively, the results of this study suggest that ECM1 possesses angiogenic properties that may promote tumor progression.

Angiogenesis Inducing Agents↗
PubMed2001

A randomized, double-blinded comparison of intrathecal morphine, sufentanil and their combination versus IV morphine patient-controlled analgesia for postthoracotomy pain.

UNLABELLED: We compared the analgesic effect of lumbar intrathecal (IT) 0.5 mg morphine (Group M, n = 10), 50 microg sufentanil (Group S, n = 10), and their combination (Group S-M, n = 10) given before general anesthesia and patient-controlled analgesia with IV morphine (Group C, n = 19) in a randomized, double-blinded study performed in patients undergoing thoracotomy. Pain visual analog scale (VAS) and morphine consumption were assessed for 24 h. In Group S-M the number of patients initially titrated with IV morphine was less than in group C (30 vs 84%, P < 0.05). Morphine requirement was higher in Group C (71 +/- 30 mg) than in Groups S (46 +/- 34 mg, P < 0.05), M (38 +/- 31 mg, P < 0.05) and S-M (23 +/- 16 mg, P < 0.01). VAS scores were significantly decreased during the first 0-11 postoperative h at rest and during the first 0-8 postoperative h on coughing in Groups M and S-M rather than in Group C. The incidence of side effects was infrequent except for urinary retention. Preoperative IT morphine or combined sufentanil and morphine could be given as a booster to achieve rapidly effective analgesia in the immediate postoperative period. IMPLICATIONS: As compared with IV patient-controlled analgesia, intrathecal morphine or combined sufentanil and morphine provided superior postoperative pain relief both at rest (11 h) and on coughing (8 h) than did IV patient-controlled analgesia morphine alone. IV morphine requirement was decreased during the first postoperative day after posterolateral thoracotomy.

Analgesia, Patient-Controlled↗
PubMed2001

Early c-Fos induction after cerebral ischemia: a possible neuroprotective role.

The role of c-Fos in neurodegeneration or neuroprotection after cerebral ischemia is controversial. To investigate whether early c-Fos induction after ischemia is associated with neuroprotection, rats were subjected to 10 minutes of transient forebrain ischemia and c-Fos expression was examined. Resistant dentate granule cells and neurons in CA2-4 displayed more robust immunoreactivity than vulnerable neurons in the CA1 region of hippocampus during early hours of reperfusion. By 6 hours after reperfusion, c-Fos immunoreactivity was greatly diminished in all areas of the hippocampus. Administration of N-acetyl-O-methyldopamine (NAMDA), a compound previously shown to protect CA1 neurons against ischemia, increased c-Fos immunoreactivity in the CA1 vulnerable region at 6 hours after ischemia and protected SK-N-BE(2)C neurons from oxygen glucose deprivation. Further in vitro study showed that NAMDA potentiated phorbol-12 myristate-13 acetate (PMA)-induced c-Fos expression, AP1 binding activity, and late gene expression determined by chloramphenicol acetyltransferase (CAT) activity from AP1 containing tyrosine hydroxylase promoter-CAT fusion gene in SK-N-BE(2)C neurons. In vivo and in vitro results showed that a neuroprotectant, NAMDA, in concert with another stimulus (for example, ischemia or PMA) up-regulates c-Fos expression and suggested that the early rise of NAMDA-induced c-Fos expression in vulnerable CA1 neurons may account for neuroprotection by means of up-regulating late gene expression for survival.

Animals↗
PubMed2001

Elements in erythrocytes of population with different thyroid hormone status.

The contents of elements K, Ca, Fe, Cu, Zn, Se, and Rb in erythrocytes of 78 cases with different thyroid hormone status have been measured by proton-induced X-ray emission and neutron activation analysis. According to the status of thyroid hormones T3, T4, TSH, FT3, and FT4 detected by radioimmunoassay, the experiment subjects were divided into four groups (i.e., hyperthyroid, hypothyroid, critical [one of thyroid hormones was abnormal], and normal). Elements contents and hormones levels of four groups were analyzed by one-way analysis of variance and correlation using an SPSS/PC statistical package. The results showed that the Se contents of four groups were not significantly different (p<0.05). Zn content of hypothyroid group was significantly higher than those of hyperthyroid and critical groups. The Zn content of the normal group was higher than that of the hypothyroid group and lower than that of the hyperthyroid and critical groups. In the hyperthyroid group, there were significant correlations between elements contents and thyroid hormones levels (except TSH), but not between elements contents and levels of thyroid hormones. However, in the hypothyroid group, relatively strong correlations have been found between elements contents and thyroid hormones levels, especially between Zn and the T3/T4 ratio, and between Zn and TSH.

Animals↗
PubMed2001

Fusion proteins from artificial and natural structural modules.

The purpose of preparing fusion proteins from designed and natural sequences is mainly twofold; it aims at the stabilization of structure and at the modification of biological activity. Fusion with beta-galactosidase, for example, can increase the intracellular stability and DDT-degrading activity of an artificial DDT-binding peptide, and fusions with a leucine zipper produce mono- and bifunctional single-chain variable domain antibody fragments or homodimeric and heterodimeric DNA-binding proteins like an artificial homodimeric HIV-1 enhancer-binding protein with increased binding specificity and repressor activity. Of importance are also short leader sequences that mediate the translocation of proteins across the cytoplasmic and the nuclear membrane. An interesting by-product of the leucine zipper-mediated dimerization of an HIV-1 enhancer-binding protein was the synthesis and the structural as well as functional characterization of a retro-leucine zipper.

Amino Acid Sequence↗
PubMed2001

Comparison of single- versus double-bolus treatments of O(6)-benzylguanine for depletion of O(6)-methylguanine DNA methyltransferase (MGMT) activity in vivo: development of a novel fluorometric oligonucleotide assay for measurement of MGMT activity.

Previous studies have demonstrated that optimal reversal of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) resistance requires complete inactivation of the DNA repair protein O(6)-methylguanine DNA methyltransferase (MGMT) for at least 24 h following BCNU administration. In preparation for clinical trials at this institution, this study was undertaken to compare the efficacy of a conventional single-bolus dose versus double-bolus dose treatments with O(6)-benzylguanine (BG) in depleting MGMT activity in vivo. In xenograft human glioma SF767 tumors, a single 30-mg/kg bolus dose of BG completely inhibited MGMT activity for at least 8 h, but approximately 50% of the basal MGMT activity recovered within 24 h. To sustain the MGMT depletion for 24 h, a second bolus injection of BG at escalating doses was administered 8 h after the first dose. Second bolus doses of 5, 10, and 15 mg/kg BG attenuated the MGMT recovery in a dose-dependent manner compared with the single 30-mg/kg BG dose alone. When the 15-mg/kg BG dose was administered 8 h after the 30-mg/kg initial dose, MGMT activity was completely inactivated in the tumor xenografts for 24 h. This double-bolus BG treatment also depleted MGMT activity in normal murine tissues, including the liver, kidney, lung, brain, spleen, and bone marrow; and the kinetics of MGMT recovery varied among these tissues. When combined with BCNU treatment, the double-bolus BG treatment would be expected to produce greater antitumor activity in future trials than the conventional single-bolus BG treatment.

Animals↗
PubMed2001

Polycyclic aromatic hydrocarbon/metal mixtures: effect on PAH induction of CYP1A1 in human HEPG2 cells.

Environmental polycyclic aromatic hydrocarbons (PAHs) and metals coexist, and such mixtures could affect the carcinogenicity of PAHs, possibly by modification of PAH induction of the PAH-bioactivating CYP1A. The effect on PAH-mediated CYP1A induction of arsenic, lead, mercury, or cadmium (ranked as the most hazardous environmental metals by the Environmental Protection Agency and the Agency for Toxic Substances and Disease Registry) has thus been investigated. Induction of CYP1A1 by benzo[a]pyrene (BAP), benzo[b]fluoranthene (BBF), dibenzo[a,h]anthracene (DBAHA), benzo[a]anthracene (BAA), or benzo[k]fluoranthene (BKF) was probed by ethoxyresorufin-O-deethylase activity (EROD) in 96-well plates of human HepG2 cells, by immunoblot analysis, and by reverse transcription-polymerase chain reaction. Cells rapidly took up PAHs (BAP, BKF) from medium; by 24 h only 14% remained in the medium, and no detectable PAH bound to well walls. Induction efficiency (relative to dimethyl sulfoxide controls) was in the order BKF (16-fold) > DBAHA (14-fold) > BAA (4-fold) > BAP (3-fold) > BBF (1-fold), all at 5 microM PAH. The metals did not markedly affect cell viability at concentrations of arsenic, 5 microM; lead, 50 microM; mercury, 5 microM; and cadmium, 5 microM. At 5 microM PAH concentration, all of the metals decreased levels of PAH-induced CYP1A1 activities (direct inhibition of EROD activity was excluded) by variable extents and in a PAH-dependent manner. With BAP as inducer decreases in induction were arsenic, 57%; cadmium, 82%; mercury, 4%; and lead, 20%. The decreases were not a consequence of transcriptional down-regulation. One possible conclusion is that these metals could diminish PAH carcinogenic potential by decreasing PAH-mediated induction of their bioactivation by CYP1A1.

Base Sequence↗
PubMed2001

In vitro investigations of tumor targeting with (99m)Tc-labeled antisense DNA.

UNLABELLED: One objective of this investigation was to determine whether chemical modifications of oligonucleotides to permit radiolabeling with gamma- or positron emitters interferes with hybridization and target cell accumulation. A second objective was to establish to a reasonable extent whether cellular accumulation of radiolabeled oligonucleotides can be explained by an antisense mechanism. METHODS: An 18mer uniform phosphorothioate DNA antisense to the messenger RNA (mRNA) of the type I regulatory subunit alpha of cyclic adenosine monophosphate-dependent protein kinase A (RI alpha) was conjugated with the N-hydroxysuccinimidyl derivative of S-acetylmercaptoacetyltriglycine (MAG3) through a primary amine/linker and investigated in vitro in cell culture. RESULTS: By surface plasmon resonance, the association kinetics between native (i.e., without amine/linker) DNA and MAG3-amide/linker-DNA were identical. Melting temperatures were also identical for native DNA, amine/linker-DNA, and MAG3-amide/linker-DNA, indicating that these chemical modifications had no detectable influence on hybridization. However, cellular accumulation of (99m)Tc-MAG3-DNA was lower than that of (35)S-MAG3-DNA, suggesting that chemical modifications can have an important influence on cellular accumulation. In tissue culture studies of ACHN tumor cells (a human renal adenocarcinoma cell type), an antisense effect was suggested by 3 findings: an increased accumulation of (35)S- or (99m)Tc-labeled antisense versus sense DNA, an increased accumulation of (99m)Tc-antisense DNA in another RI alpha-positive tumor cell line (LS174T) but not in a murine transfected control cell line (HC-2), and the disappearance of the increased cellular accumulation of (99m)Tc-antisense DNA with increasing dosage of antisense DNA. Higher than expected cellular accumulations of about 10(5) antisense DNAs per cell over 24 h suggest stabilization of the target mRNA or increased mRNA production by the presence of the antisense DNA. In support of this suggestion, we observed, first, an increased incorporation of uridine-5'-triphosphate into RNA in cells exposed to the antisense DNA but not to the control DNA and, second, an increase in target mRNA expression in cells exposed to the antisense DNA but not to the control DNA. CONCLUSION: This evidence suggests tumor cell accumulation by an antisense mechanism. Moreover, the high level of DNA accumulation suggests that a rapid target mRNA turnover or transcription rate may be an important determinant of tumor counting rates.

Autoradiography↗
PubMed2001

The role of hypertension-related gene in aortic vascular smooth muscle cells from mice and rats.

OBJECTIVE: To study the role of hypertension-related gene (HRG-1) in cardiovascular disease. METHODS: The expression of HRG-1 was analyzed with RT-PCR and Northern blotting. Vascular smooth muscle cell (VSMC) proliferation was measured with 3H-TdR incorporation and was confirmed with histological analysis. RESULTS: Northern blot analysis showed that HRG-1 mRNA was expressed not only in VSMC, but also in various rat tissues (heart, brain, lung, kidney, and liver). In addition, the expression of HRG-1 mRNA in heart, brain, kidney and liver of spontaneously hypertensive rat (SHR) was lower than that in the same tissues of Wistar-Kyotorat (WKY). Semi-quantitative RT-PCR and histological analysis showed that the expression of HRG-1 mRNA in ApoE-knockout mice and in animal models of restenosis was decreased and neointimal formation was observed in both models. ET, AII, and IL-1 stimulating VSMC proliferation reduced the expression of HRG-1 mRNA of VSMC. Atrial natriuretic factor (ANF), calcitonin gene-related peptide and adrenomedullin, inhibited VSMC proliferation and elevated the expression of HRG-1 mRNA. These effects could be blocked or attenuated by their corresponding antagonists or antibodies. CONCLUSION: HRG-1 is a gene related to VSMC proliferation. It may play an important role in several occlusive cardiovascular diseases including atherosclerosis, restenosis and hypertension.

Animals↗