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Exley GE, Tang C, McElhinny AS, Warner CM. Expression of caspase and BCL-2 apoptotic family members in mouse preimplantation embryos. Biol Reprod 1999; 61:231-9. [PMID: 10377054 DOI: 10.1095/biolreprod61.1.231] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Apoptosis, as determined by blastomere and DNA fragmentation, occurs in many preimplantation mouse embryos. To investigate which genes contribute to apoptosis in preimplantation embryos, we used the reverse transcription-polymerase chain reaction to assess mRNA levels for seven genes in the caspase family and seven genes in the BCL-2 family. All caspase mRNAs were detectable in oocytes, while expression in preimplantation embryos varied in a stage-specific manner. An assay for group II caspase enzymatic activity showed that although transcripts for these caspases could not be detected in zygotes, proteolytic activity could be detected in polar bodies, fragmented zygotes, and zygotes treated with staurosporine. This suggests that maternal caspases are inherited during oogenesis. Transcripts for some members of the BCL-2 family could be detected at every stage of preimplantation development. Transcripts for other members were rarely detected. When BCL-2 and BAX protein levels were assessed using immunofluorescence, both proteins were detected in zygotes and in blastocysts. When fragmented blastocysts were compared to normal blastocysts, levels of BCL-2 immunofluorescence tended to be lower in fragmented blastocysts. This result supports a model in which the ratio of BCL-2 to BAX is altered in apoptotic embryos.
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327
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Chen Z, Tang C, Yu JC. Simultaneous Determination of Inorganic Anions and Organic Acids in Environmental Samples by Capillary Zone Electrophoresis with Indirect UV Detection. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1521-4168(19990701)22:7<379::aid-jhrc379>3.0.co;2-g] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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328
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Baldisseri DM, Rustandi RR, Zhang Z, Tang C, Bair CL, Landar A, Landar A, Zimmer DB, Weber DJ. 1H, 13C and 15N NMR sequence-specific resonance assignments for rat apo-S100A1(alpha alpha). JOURNAL OF BIOMOLECULAR NMR 1999; 14:91-92. [PMID: 10382312 DOI: 10.1023/a:1008301518346] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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329
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Liu S, Crider AM, Tang C, Ho B, Ankersen M, Stidsen CE. 2-pyridylthioureas: novel nonpeptide somatostatin agonists with SST4 selectivity. Curr Pharm Des 1999; 5:255-63. [PMID: 10101224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Somatostatin [somatotropin release-inhibiting factor (SRIF)] is a cyclic tetradecapeptide that is a potent inhibitor of growth hormone (GH) secretion from the anterior pituitary. In addition to the inhibitory effects on GH-release, SRIF-14 and SRIF-28, a 28-amino acid form of SRIF extended from the N-terminal end, inhibit the release of a variety of other peptides including glucagon, insulin, and gastrin, and both peptides act as neurotransmitters and neuromodulators in the central nervous system and the periphery. SRIF exerts its potent inhibitory effects following binding to high affinity SRIF receptors (ssts) that have been identified on target tissues. The recent cloning of five ssts has confirmed that the effects of SRIF are mediated by a family of G protein-coupled receptors (sst1-5). Based on structural and pharmacological properties sst2, sst3, and sst5 belong to the SRIF1 receptor subclass, and the sst1 and sst4 subtypes comprise the SRIF2 subclass. The major difference between these two subclasses is that SRIF1 receptors bind octapeptide and hexapeptide SRIF-14 analogs with high affinity, while SRIF2 receptors bind these analogs with drastically reduced affinity. A screening program was initiated to identify a lead nonpeptide with affinity for sst1-5 receptors. The search focused on a scaffold with the following attachments: (1) a heteroaromatic nucleus to mimic the Trp8 residue, (2) a nonheteroaromatic nucleus to mimic Phe7, and (3) a primary amine or other basic group to mimic the Lys9 residue of SRIF-14. Using these criteria, a novel thiourea (NNC 26-9100, 17) was discovered as a structural lead. The key fragments in this compound are a heteroaromatic moiety (pyridine), an aromatic group, and a basic imidazole group connected through a thiourea scaffold. Compound 17 exhibited a Ki = 6 nM at sst4 receptors with a 100-fold sst4/sst2 selectivity and was shown to be a full agonist at this receptor subtype. This article will review the literature on the design and development of nonpeptide somatostatin receptor ligands and the therapeutic potential of these agents. Furthermore, our work on the development of 2-pyridylthioureas as sst4 receptor agonists will be described.
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330
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Crider AM, Liu S, Tang C, Ho B, Ankersen M, Stidsen CE. 2-Pyridylthioureas: Novel Nonpeptide Somatostatin Agonists with SST4 Selectivity. Curr Pharm Des 1999. [DOI: 10.2174/1381612805666230109213422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Somatostatin [somatotropin release-inhibiting factor (SRIF)] is a cyclic tetradecapcptiJc that is a potent inhibitor of growth hormone (GH) secretion from the anterior pituitary. In addition to the inhibitory effects on GH-release, SRIF-14 and SRJF-28, a 28-amino acid form of SRIF extended from the N-terminal end, inhibit the release of a variety of other peptides including glucagon, insulin, and gastriri, and both peptides act as neurotransmitters and neuromodulators in the central nervous system and the periphery. SRIF exerts its potent inhibitory effects following binding to high affinity SRIF receptors (ssts) that have been identified on target tissues. The recent cloning of five ssts has confirmed that the effects of SRIF are mediated by a family of G protein-coupled receptors (sst1-5). Based on structural and pharmacological properties sst2, sst3, and sst5 belong to the SRIF1 receptor subclass, and the sst1 and sst4 subtypes comprise the SRIF2 subclass. The major difference between these two subclasses is that SRIF1 receptors bind octapeptide and hexapeptide SRIF-14 analogs with high affinity, while SRIF2 receptors bind these analogs with drastically reduced affinity.
A screening program was initiated to identify a lead nonpeptide with affinity for sst1-5 receptors. The search focused on a scaffold with the following attachments: (I) a heteroaromatic nucleus to mimic the Trp8 residue, (2) a nonheteroaromatic nucleus to mimic Phe7, and (3) a primary amine or other basic group to mimic the Lys9
residue of SRIF-14. Using these criteria, a novel thiourea (NNC 26-9100, 17) was discovered as a structural lead. The key fragments in this compound are a heteroaromatic moiety (pyridine), an aromatic group, and a basic imidazole group connected through a thiourea scaffold. Compound 17 exhibited a Ki = 6 nM at sst4 receptors with a JOO-fold sst4/sst2 selectivity and was shown to be a full agonist at this receptor subtype. This article will review the literature on the design and development of nonpeptide somatostatin receptor ligands and the therapeutic potential of these agents. Furthermore, our work on the development of 2-pyridylthioureas as sst4 receptor agonists will be described.
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331
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Lu J, Lin CL, Tang C, Ponder JW, Kao JL, Cistola DP, Li E. The structure and dynamics of rat apo-cellular retinol-binding protein II in solution: comparison with the X-ray structure. J Mol Biol 1999; 286:1179-95. [PMID: 10047490 DOI: 10.1006/jmbi.1999.2544] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The structure and dynamics of rat apo-cellular retinol binding protein II (apo-CRBP II) in solution has been determined by multidimensional NMR analysis of uniformly enriched recombinant rat 13C, 15N-apo-CRBP II and 15N-apo-CRBP II. The final ensemble of 24 NMR structures has been calculated from 3274 conformational restraints or 24.4 restraints/residue. The average root-mean-square deviation of the backbone atoms for the final 24 structures relative to their mean structure is 1.06 A. Although the average solution structure is very similar to the crystal structure, it differs at the putative entrance to the binding cavity, which is formed by the helix-turn-helix motif, the betaC-betaD turn and the betaE-betaF turn. The mean coordinates of the main-chain atoms of amino acid residues 28-38 are displaced in the solution structure relative to the crystal structure. The side-chain of F58, located on the betaC-betaD turn, is reoriented such that it interacts with L37 and no longer blocks entry into the ligand-binding pocket. Residues 28-35, which form the second helix of the helix-turn-helix motif in the crystal structure, do not exhibit a helical conformation in the solution structure. The solution structure of apo-CRBP II exhibits discrete regions of backbone disorder which are most pronounced at residues 28-32, 37-38 and 73-76 in the betaE-betaF turn as evaluated by the consensus chemical shift index, the root-mean-square deviation, amide 1H exchange rates and 15N relaxation studies. These studies indicate that fluctuations in protein conformation occur on the microseconds to ms time-scale in these regions of the protein. Some of these exchange processes can be directly observed in the three-dimensional 15N-resolved NOESY spectrum. These results suggest that in solution, apo-CRBP II undergoes conformational changes on the microseconds to ms time-scale which result in increased access to the binding cavity.
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Prueksaritanont T, Ma B, Tang C, Meng Y, Assang C, Lu P, Reider PJ, Lin JH, Baillie TA. Metabolic interactions between mibefradil and HMG-CoA reductase inhibitors: an in vitro investigation with human liver preparations. Br J Clin Pharmacol 1999; 47:291-8. [PMID: 10215754 PMCID: PMC2014217 DOI: 10.1046/j.1365-2125.1999.00903.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/1998] [Accepted: 11/13/1998] [Indexed: 11/20/2022] Open
Abstract
AIMS To determine the effects of mibefradil on the nletabolism in human liver microsomal preparations of the HMG-CoA reductase inhibitors simvastatin, lovastatin, atorvastatin, cerivastatin and fluvastatin. METHODS Metabolism of the above five statins (0.5, 5 or 10 microM), as well as of specific CYP3A4/5 and CYP2C8/9 marker substrates, was examined in human liver microsomal preparations in the presence and absence of mibefradil (0.1-50 microM). RESULTS Mibefradil inhibited, in a concentration-dependent fashion, the metabolism of the four statins (simvastatin, lovastatin, atorvastatin and cerivastatin) known to be substrates for CYP3A. The potency of inhibition was such that the IC50 values (<1 microM) for inhibition of all of the CYP3A substrates fell within the therapeutic plasma concentrations of mibefradil, and was comparable with that of ketoconazole. However, the inhibition by mibefradil, unlike that of ketoconazole, was at least in part mechanism-based. Based on the kinetics of its inhibition of hepatic testosterone 6beta-hydroxylase activity, mibefradil was judged to be a powerful mechanism-based inhibitor of CYP3A4/5, with values for Kinactivation, Ki and partition ratio (moles of mibefradil metabolized per moles of enzyme inactivated) of 0.4 min(-1), 2.3 microM and 1.7, respectively. In contrast to the results with substrates of CYP3A, metabolism of fluvastatin, a substrate of CYP2C8/9, and the hydroxylation of tolbutamide, a functional probe for CYP2C8/9, were not inhibited by mibefradil. CONCLUSION Mibefradil, at therapeutically relevant concentrations, strongly suppressed the metabolism in human liver microsomes of simvastatin, lovastatin, atorvastatin and cerivastatin through its inhibitory effects on CYP3A4/5, while the effects of mibefradil on fluvastatin, a substrate for CYP2C8/9, were minimal in this system. Since mibefradil is a potent mechanism-based inhibitor of CYP3A4/5, it is anticipated that clinically significant drug-drug interactions will likely ensue when mibefradil is coadministered with agents which are cleared primarily by CYP3A-mediated pathways.
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333
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Cui Z, Chen B, Tang C. [Experimental study of cultured autologous keratinocyte sheet(Auto-CKS) and allodermis composite skin grafted onto open wound of rats]. ZHONGHUA ZHENG XING SHAO SHANG WAI KE ZA ZHI = ZHONGHUA ZHENG XING SHAO SHANG WAIKF [I.E. WAIKE] ZAZHI = CHINESE JOURNAL OF PLASTIC SURGERY AND BURNS 1999; 15:109-11. [PMID: 11501134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
OBJECTIVE Investigate the "take" and histological changes of grafted auto-CKS and allo-dermis composite skin. METHODS Thirty Sprague-Dawley rats were divided into group auto-CKS and group allo-dermis composite skin. All wounds were dressed after grafting. Wound healing and "take" of grafts were determined for 90 days after grafting. Biopsies of wound tissue including grafts were collected at regular intervals for histological analysis to check the reconstruction of epidermis-dermis junction (EDJ) and fate of allo-dermis of the composite skin. RESULTS In group auto-CKS, the "take" of grafts was pretty good, but the quality and histological structure of CKS was not good enough, the proliferated collagen fibers were disorderly arranged, and the CKS was too thin to withstand abrasion and tended to worn out and contracted severely. On the other hand, the "take" as well as the quality, histological structure, abrasion resistance and contraction of composite skin in the allo-dermis composite skin group were much better than that of group auto-CKS. Up to 90 days after grafting, the allo-dermis still existed without obvious signs of immuno-rejection. CONCLUSION The CKS was not suitable for the wound of full thickness skin defect, while the composite skin composed of auto-CKS and treated allo-dermis unfolded the potential encouraging prospects.
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334
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Dong LW, Yang J, Tong LJ, Tang C, Liu MS. Transcriptional regulation of alpha1-adrenoceptor gene in the rat liver during different phases of sepsis. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1453:207-15. [PMID: 10036318 DOI: 10.1016/s0925-4439(98)00102-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Changes in alpha1-adrenoceptor (alpha1AR) gene expression in the rat liver during different phases of sepsis were studied. Sepsis was induced by cecal ligation and puncture (CLP). Septic rats exhibit two metabolically distinct phases: an initial hyperglycemic phase (9 h after CLP, early sepsis) followed by a hypoglycemic phase (18 h after CLP; late sepsis). The [3H]prazosin binding studies show that the density of alpha1AR was increased by 30% during the early phase while it was decreased by 24% during the late phase of sepsis. Western blot analyses reveal that alpha1AR protein level was elevated by 48% during early sepsis but was decreased by 55% during late sepsis. Northern blot analyses depict that the steady-state level of alpha1bAR mRNA was enhanced by 21% during the early phase but was declined by 29% during the late phase of sepsis. Nuclear run-off assays show that the transcription rate of alpha1bAR gene transcript was increased by 76% during early sepsis while it was decreased by 29% during late sepsis. The actinomycin D pulse-chase studies indicate that the half-life of alpha1bAR mRNA remained unaffected during the early and the late phases of sepsis. These findings demonstrate that during the early phase of sepsis, the increase in the rate of transcription of alpha1bAR gene paralleled with the elevations in the alpha1bAR mRNA abundance and alpha1AR protein level, while during the late phase of sepsis, the decrease in the rate of transcription of alpha1bAR gene coincided with the declines in the alpha1bAR mRNA abundance and the alpha1AR protein level in the rat liver. These observations indicate that the altered expression of alpha1AR genes in the rat liver during the progression of sepsis was regulated transcriptionally.
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335
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Tang C, Turner NC. The influence of alkalinity and water stress on the stomatal conductance, photosynthetic rate and growth of Lupinus angustifolius L. and Lupinus pilosus Murr. ACTA ACUST UNITED AC 1999. [DOI: 10.1071/ea98132] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A glasshouse experiment examined the effect of water stress on the growth of
Lupinus angustifolius L. and
Lupinus pilosus Murr. grown on an acid sandy soil, a
limed sandy soil and an alkaline clay soil. Decreasing soil water content
decreased the stomatal conductance and photosynthetic rate, and reduced plant
growth. The responses of both species to water stress were generally similar
in the sand and limed soils, but in the alkaline soil,
L. angustifolius grown with limited water had markedly
lower conductances and photosynthetic rates than the plants in the other soils
at equivalent soil water contents. In adequately watered plants, the lupin
species differed substantially in their growth response to soil types. Whereas
the growth of L. pilosus was unaffected, the shoot dry
weight of L. angustifolius grown on the limed and
alkaline soils for 25–44 days was reduced by 32–54 and
44–86%, respectively, compared with the growth in the acid soil.
The poor growth of L. angustifolius appeared to be
primarily due to its poor root growth. In the alkaline soil, water stress
reduced rather than stimulated root growth. The results suggest that, in the
field, the limited root growth of L. angustifolius on
alkaline soils will exacerbate water deficits when the topsoil dries out in
the latter part of the season.
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336
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Brahn E, Lehman TJ, Peacock DJ, Tang C, Banquerigo ML. Suppression of coronary vasculitis in a murine model of Kawasaki disease using an angiogenesis inhibitor. Clin Immunol 1999; 90:147-51. [PMID: 9884364 DOI: 10.1006/clim.1998.4645] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Coronary arteritis can be induced in C57BL/6 mice with a single intraperitoneal (ip) injection of Lactobacillus casei cell fragments. Histologic sections resemble the vasculitis and aneurysms observed in the medium-sized coronary arteries of children with Kawasaki disease. Since endothelial cells could play an important role in the development of vasculitis, a recently described angiogenesis inhibitor that is not an immunosuppressive agent, AGM-1470 (derived from Aspergillus fumigatus), was used to evaluate its therapeutic potential in this model. A total of 32 mice were administered 0.5 mg of sterile L. casei preparation ip on day 0 and randomized to either a treatment (AGM-1470, 27mg/kg sc alternate days) or a control (vehicle only) protocol. Hearts were harvested on day 14 (early disease) or at the end of the study on day 28 (established disease). Histologic sections were scored blindly for vasculitis. Day 14 sections from both protocols manifested only minimal disease, indicating that the vasculitis had not yet matured. By day 28, the AGM-1470 group had significantly less coronary vasculitis than the control group (0.7 vs 2.6, p < 0.005, respectively). These studies suggest that endothelial cells may play an active role in this pathologic process and that angiogenesis inhibitors, such as AGM-1470, could be useful tools for the treatment and understanding of vasculitis.
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Abstract
The emergence and spread of bacteria resistant to antimicrobial drugs is a major public health problem with a growing number of infections becoming virtually untreatable. There is a need to develop interventions both to prevent and to treat diseases caused by multi-resistant microbes. We review some recently developed methods (including whole genome nucleotide sequencing projects) to study bacterial pathogenesis, and discuss how knowledge gained from understanding the molecular mechanisms of disease can be applied to combat the threat of infectious diseases.
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Brand JD, Tang C, Rathjen AJ. Adaptation of Lupinus angustifolius L. and L. pilosus Murr. to calcareous soils. ACTA ACUST UNITED AC 1999. [DOI: 10.1071/ar98177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Current varieties of narrow-leafed lupin
(Lupin angustifolius L.) are poorly adapted to alkaline
and calcareous soils found commonly throughout the south-estern Australian
cropping zone. Apot experiment compared the growth of
Lupinus angustifolius cv. Gungurru with
L. pilosus P20954 in a range of soils collected
throughout South Australia. The soils displayed a range of texture (clay,
3–82%), pH (1:5 soil:H2O,
7·0–9·6), and calcium carbonate content
(CaCO3, 0–47%). Potting mix (pH
5·8) was used as the control. The plants were grown for 7 weeks with
weekly measurements of chlorosis score and leaf number. At harvest, dry
weights were recorded and the youngest fully expanded leaves were analysed for
nutrient concentrations.
The line P20954 grew much better in all the soils than Gungurru in terms of
plant dry weight relative to the control soil, this being particularly evident
in the calcareous soils. Chlorosis score correlated highly with shoot dry
weight for Gungurru, but not for P20954. The main soil factor contributing to
the chlorosis score of Gungurru was CaCO3 content,
whereas none of the soil factors significantly affected P20954, although in
Weeks 2 and 3 chlorosis score correlated with CaCO3
content. The dry weight of Gungurru was affected by a combination of factors
including clay content, pH, and CaCO3 content, whereas
the dry weight of P20954 was affected by most of the soil factors measured.
The dry weight of P20954 was positively correlated with aluminium and
magnesium concentrations. Concentrations of all nutrients were above critical
levels for both genotypes grown in all soils. The results indicate that
L. pilosus has the potential to be grown in areas where
current varieties of L. angustifolius are poorly
adapted.
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Fong TA, Shawver LK, Sun L, Tang C, App H, Powell TJ, Kim YH, Schreck R, Wang X, Risau W, Ullrich A, Hirth KP, McMahon G. SU5416 is a potent and selective inhibitor of the vascular endothelial growth factor receptor (Flk-1/KDR) that inhibits tyrosine kinase catalysis, tumor vascularization, and growth of multiple tumor types. Cancer Res 1999; 59:99-106. [PMID: 9892193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
SU5416, a novel synthetic compound, is a potent and selective inhibitor of the Flk-1/KDR receptor tyrosine kinase that is presently under evaluation in Phase I clinical studies for the treatment of human cancers. SU5416 was shown to inhibit vascular endothelial growth factor-dependent mitogenesis of human endothelial cells without inhibiting the growth of a variety of tumor cells in vitro. In contrast, systemic administration of SU5416 at nontoxic doses in mice resulted in inhibition of subcutaneous tumor growth of cells derived from various tissue origins. The antitumor effect of SU5416 was accompanied by the appearance of pale white tumors that were resected from drug-treated animals, supporting the antiangiogenic property of this agent. These findings support that pharmacological inhibition of the enzymatic activity of the vascular endothelial growth factor receptor represents a novel strategy for limiting the growth of a wide variety of tumor types.
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340
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Liu A, Tang C. Comparative performance of Lupinus albus genotypes in response to soil alkalinity. ACTA ACUST UNITED AC 1999. [DOI: 10.1071/ar98205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Narrow-leafed lupin (Lupinus angustifolius L.) grows
poorly on alkaline soils, whereas white lupin
(Lupinus albus L.) grows relatively well. This study
aimed at examining genotypic variations of white lupins grown in limed acid
and alkaline soils in the glasshouse and to test whether the glasshouse
findings correlated with those observed in the field.
Twelve white lupin genotypes were tested for their tolerance of limed and
alkaline soils in the glasshouse. In limed soils compared with the control
soil, genotypic variation in shoot growth ranged from 58 to 80%, root
weight from 49 to 72%, and leaf chlorophyll concentration from 47 to
96%. In the alkaline soil, shoot weight ranged from 75 to 110%,
root weight from 39 to 63%, and chlorophyll concentration from 58 to
94% of the control. However, iron chlorosis did not negatively
correlate with shoot growth of the genotypes on the limed or alkaline soils.
The results suggest that iron chlorosis may not be used as a sole indicator
for selecting tolerant albus lupins for alkaline soils. Nineteen lines
including those used in the glasshouse were compared in the field for their
ability to grow on an alkaline clay. Large genotypic variation in early shoot
growth was also found; shoot weight on the alkaline soil relative to an acid
soil ranged from 38 to 85%. However, growth performance of the white
lupin genotypes in response to the alkaline soil did not correlate with those
in the glasshouse, indicating that factors other than soil alkalinity might
also be important for the growth of albus lupin. Screening techniques to
identify tolerant genotypes for alkaline soils need to be further developed.
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Abstract
Current attempts at preventing infections caused by group B Neisseria meningitidis are largely directed on generating immune responses to outer membrane proteins or the lipopolysaccharide of this organism. We suggest an alternative approach: the use of a live, attenuated strain of Neisseria meningitidis which could be delivered mucosally to elicit both local and systemic immune responses.
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Tang L, Jiang D, Nie A, Guo X, Tang C, Liu X. [Effects of subretinal fluid containing proteins with different molecular weights on the proliferative vitreoretinopathy]. HUNAN YI KE DA XUE XUE BAO = HUNAN YIKE DAXUE XUEBAO = BULLETIN OF HUNAN MEDICAL UNIVERSITY 1998; 22:119-22. [PMID: 9868051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The stimulating effects of subretinal fluid (SRF) containing different molecular weight proteins which were isolated by fast performance liquid chromatography (FPLC) and ultrafiltration on the proliferative vitreoretinopathy (PVR) were investigated. The results showed that (1) the PVR was induced by 10-30 kD proteins injecting vitreously, and the forming duration of PVR was about two weeks; (2) the location of inducing PVR was mainly on medullary ray area in the rabbit eye; (3) In the SRF there were growth factors which were mainly those proteins with molecular weight between 10 kD and 30 kD.
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Zeng X, Zhang J, Tang C. [The protective effect of captopril on the ischemic myocardium in dogs through coronary sinus retroperfusion]. HUNAN YI KE DA XUE XUE BAO = HUNAN YIKE DAXUE XUEBAO = BULLETIN OF HUNAN MEDICAL UNIVERSITY 1998; 22:22-4, 28. [PMID: 9868021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The protective effect of coronary sinus retroperfusion of Captopril on the ischemic myocardium was observed in dogs with acute myocardial infarction (AMI). The results showed that the infarction size and the level of coronary sinus plasma endothelin (ET) and manodialdenyde (MDA) were smaller and lower when Captopril was administered by coronary sinus retroperfusion than that by systemic intravenous injection. These results suggest that (1) Captopril can be distributed adequately in the local ischemic myocardial zones when administered by coronary sinus retroperfusion in the presence of coronary artery occlusion, (2) Captopril can more effectively protect ischemic myocardium by inhibition of the ET release and against the oxygen free radicals in ischemic myocardial area when used by coronary sinus retroperfusion.
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Jones KA, Borowsky B, Tamm JA, Craig DA, Durkin MM, Dai M, Yao WJ, Johnson M, Gunwaldsen C, Huang LY, Tang C, Shen Q, Salon JA, Morse K, Laz T, Smith KE, Nagarathnam D, Noble SA, Branchek TA, Gerald C. GABA(B) receptors function as a heteromeric assembly of the subunits GABA(B)R1 and GABA(B)R2. Nature 1998; 396:674-9. [PMID: 9872315 DOI: 10.1038/25348] [Citation(s) in RCA: 781] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The principal inhibitory neurotransmitter GABA (gamma-aminobutyric acid) exerts its effects through two ligand-gated channels, GABA(A) and GABA(C) receptors, and a third receptor, GABA(B) , which acts through G proteins to regulate potassium and calcium channels. Cells heterologously expressing the cloned DNA encoding the GABA(B)R1 protein exhibit high-affinity antagonist-binding sites, but they produce little of the functional activity expected from studies of endogenous GABA(B) receptors in the brain. Here we describe a new member of the GABA(B) polypeptide family, GABA(B)R2, that shows sequence homology to GABA(B)R1. Neither GABA(B)R1 nor GABA(B)R2, when expressed individually, activates GIRK-type potassium channels; however, the combination of GABA(B)R1 and GABA(B)R2 confers robust stimulation of channel activity. Both genes are co-expressed in individual neurons, and both proteins co-localize in transfected cells. Moreover, immunoprecipitation experiments indicate that the two polypeptides associate with each other, probably as heterodimers. Several G-protein-coupled receptors (GPCRs) exist as high-molecular-weight species, consistent with the formation of dimers by these receptors, but the relevance of these species for the functioning of GPCRs has not been established. We have now shown that co-expression of two GPCR structures, GABA(B)R1 and GABA(B)R2, belonging to the same subfamily is essential for signal transduction by GABA(B) receptors.
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Buchsbaum MS, Fallon JH, Wei TC, Guich S, Spiegel-Cohen J, Hamilton M, Tang C. A method of basal forebrain anatomical standardization for functional image analysis. Psychiatry Res 1998; 84:113-25. [PMID: 10710168 DOI: 10.1016/s0925-4927(98)00052-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Functional as well as structural assessment of the basal forebrain has mostly focused on the dorsal caudate and putamen in axial slices where they are easily outlined or their centers located with stereotaxic methods. The more ventral extent of the basal forebrain, where the irregular form and indistinct boundaries of the nucleus accumbens and substantia innominata are difficult to trace and where the brain's ventral surface may contribute partial volume artifacts to measurement, has been less studied. We present a method based on coronal sections, landmarks placed on clearly visible anchor points, and the computational technique of thin-plate spline warping which allows the alignment of groups of individuals to common coordinates for pixel-by-pixel statistical mapping. The reliability of the landmarks across independent raters yields a median absolute difference of 1.3-1.6 mm. The validity of the method is confirmed by variance maps which reveal significant decreases in variance over spindle and bounding box alignment.
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Liu S, Tang C, Ho B, Ankersen M, Stidsen CE, Crider AM. Nonpeptide somatostatin agonists with sst4 selectivity: synthesis and structure-activity relationships of thioureas. J Med Chem 1998; 41:4693-705. [PMID: 9822540 DOI: 10.1021/jm980118e] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Utilizing NNC 26-9100 (11) as a structural lead, a variety of nonpeptide derivatives of somatostatin were synthesized and evaluated for sst2 and sst4 receptor binding affinity. A novel thiourea scaffold was utilized to attach (1) a heteroaromatic nucleus to mimic the Trp8 residue, (2) a nonheteroaromatic nucleus to mimic Phe7, and (3) a primary amine or other basic group to mimic the Lys9 residue of somatostatin. Displacement studies were carried out using membranes from cell lines expressing ssts [BHK cells (sst4) and HEK 293 cells (sst2)] utilizing [125I]Tyr11-SRIF as the radioligand. Several thioureas (11, 38, 39, 41, and 42) and the urea 66 exhibited Ki values of less than 100 nM. The thioureas 11 (Ki = 6 nM) and 41 (Ki = 16 nM) and the urea 66 (Ki = 14 nM) are believed to be the most potent nonpeptide sst4 agonists known. Since the thiourea 11 and the urea 66 exhibit high sst4 selectivity, these novel nonpeptide derivatives may be useful tools for studying the sst4 receptor. Studies are currently in progress to evaluate the therapeutic potential of NNC 26-9100 (11) in the treatment of glaucoma.
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Quan B, Tang C, Wang D. [Activation of CD4 T lymphocyte and release of interleukin-5 in airway from patients with atopic asthmatics]. ZHONGHUA YI XUE ZA ZHI 1998; 78:827-9. [PMID: 11038777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
OBJECTIVE To evaluate the action of CD4T cell and release of interleukin-5 in airway from patients with atopic asthma by the allergen-specific stimulation. METHODS Twelve atopic asthmatics (AA), 9 atopic non-asthmatics (AN), and 10 normal controls(N) underwent whole-lung inhalation challenge with house dust mite allergen (HDM) extract. The Levels of CD4CD25T lymphocytes, eosinophils(EOS), interleukin-5 (IL-5) and eosinophil cationic protein (ECP) in bronchoalveolar lavage (BAL) and peripheral blood mononuclear cells (PBMC) were investigated with and without HDM challenge. RESULTS AA differed from AN in having late airway reactions (LAR) after HDM inhalation (P < 0.01), which was correlated with an percentage of BAL eosinophils, CD4CD25T cell IL-5 production and ECP release. CONCLUSION These findings suggest that the activation of CD4T lymphocytes is correlated with both asthmatic and atopic status. The allergen-specific stimulation is believed to play a major role in CD4 T cell activation in atopic asthma. IL-5 is selective cytokine for EOS activation and modulating local eosinophil recruitment and activation in airway.
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Astrakianakis G, Svirchev L, Tang C, Janssen R, Anderson J, Band P, Le N, Fang R, Bert J. Industrial hygiene aspects of a sampling survey at a bleached-kraft pulp mill in British Columbia. AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL 1998; 59:694-705. [PMID: 9794067 DOI: 10.1080/15428119891010875] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
To validate exposure estimates used to investigate correlations between exposure and cancer risk, 1678 personal measurements were collected for 46 job titles during 73 day shifts at a bleached-kraft pulp mill. Measurements included shift-long average and short-term exposures to carbon monoxide, chlorine dioxide (ClO2), and hydrogen sulfide; and shift-long average exposures to calcium oxide and wood dust (WD). Overall results indicate low levels of exposure with a few noteworthy exceptions. Although ClO2 was the exclusive bleaching agent, 77 area samples indicated that chlorine (Cl2), not ClO2 was present in all areas apart from the chemical preparation area (chem-prep) and during a pulp spill. The highest shift-long exposures to Cl2 were measured in the chip yard and are attributed to uncontrolled stack emissions. Finally, WD samples collected from several laborers significantly exceeded regulatory limits, with the highest exposures measured in the steam and recovery area. For short-term exposures to ClO2 in chem-prep, 12 of 17 data-logging electro-chemical sensor sample results showed at least one peak that exceeded the short-term exposure limit of 0.3 ppm. The use of data-logging equipment quantified short-term exposures that previously had been characterized only anecdotally. The peaks were correlated with tasks and upset conditions and, given their transient nature, these exceedances could not have been detected using shift-long average-based sampling devices. Since the respiratory effects of significant short-term exposures to irritant gases such as Cl2 and ClO2 are well-documented, data-logging instruments are necessary to characterize exposures in the pulp and paper industry.
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Abstract
We report an unusual case of malocclusion following a history of apparently blunt trauma. No maxillary or mandibular fractures were identified. The malocclusion persisted for several days. Finally computed tomography was performed, which revealed a foreign body in the infratemporal fossa. A 4-cm pencil was extracted from the patient's right temporomandibular joint.
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Quan B, Tang C, Wang D. [CD4+ T cell activation and IL-5 production in atopic and nonatopic asthmatics]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 1998; 21:604-6. [PMID: 11477878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
OBJECTIVE To understand the reasons and roles of CD4+ T cell activation and IL-5 production in atopic and asthmatic patients. METHOD Bronchoalveolar lavage(BAL) cells and peripheral blood mononuclear cells (PBMC) from 12 atopic and 10 nonatopic asthmatics, 9 atopic nonasthmatics, and 10 normal controls were cultured with or without house dust mite(HDM), CD4+ T cell activation, and IL-5 production were assessed. RESULT The percentage of CD4+, CD25+ in unstimulated PBMC cultures were not significantly different in the four groups, but it increased following HDM stimulation in both PBMC and BAL cultures in two atopic groups(P < 0.01). The percentage of CD4+, CD25+ in unstimulated BAL cell culture increased in two asthmatic groups (P < 0.05, P < 0.01). The levels of spontaneous IL-5 released from both BALF cells and PBMC in two asthmatic groups were higher than those in AN and N (P < 0.05, P < 0.01). A significant elevation in IL-5 release following HDM stimulation in PBMC and BALF cells was observed in the both asthmatic and atopic groups; but the value in AA was higher than that in NAA, and it was also higher in BALF cells than in PBMC. CONCLUSION The allergen stimulation is important reasons for CD4+ T cell activation and IL-5 production in atopics. CD4+ T cell activation and IL-5 production are common feature in atopic and nonatopic asthma, it correlates with both asthmatic and atopic status.
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