1051
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Chen NH, Xu C, Coffey LL, Reith ME. [3H]WIN 35,428 [2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane] binding to rat brain membranes. Comparing dopamine cell body areas with nerve terminal regions. Biochem Pharmacol 1996; 51:563-6. [PMID: 8619903 DOI: 10.1016/0006-2952(95)02208-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Potential differences between somatodendritic acid and axonal dopamine transporters were examined by comparing the binding constants of [3H]WIN 35, 428 [2 beta-carbomethoxy- 3 beta-(4-fluorophenyl)tropane] binding to membranes prepared from the rat ventral mesencephalon, containing A9 and A10 dopamine cell bodies, and from the nucleus accumbens. Saturation analysis of [3H]WIN 35,428 binding, in the presence of compounds to occlude norepinephrine and serotonin transporters, was performed by both the "unlabeled" method (varying unlabeled ligand) and "labeled" method (varying radioligand). The density of binding was substantially lower in the ventral mesencephalon than in the nucleus accumbens, but the binding affinity was only slightly different. Likewise, the differences between the two regions in the inhibitory potency of cocaine and GBR 12909 [1-(2-di(4-fluorophenyl)-methoxy-ethyl)4-(3-phenylpropyl)piperazine] were not substantial. The results suggest that somatodendritic and axonal dopamine transporters in the ventral mesencephalon and nucleus accumbens are not very different as far as their binding domains for uptake blockers such as cocaine and GBR 12909 are concerned.
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1052
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Dutta AK, Xu C, Reith ME. Structure-activity relationship studies of novel 4-[2-[bis(4-fluorophenyl)methoxy]ethyl]-1-(3-phenylpropyl)piperidine analogs: synthesis and biological evaluation at the dopamine and serotonin transporter sites. J Med Chem 1996; 39:749-56. [PMID: 8576918 DOI: 10.1021/jm9506581] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several analogs of the potent dopamine (DA) transporter ligand 4-[2-[bis(4-fluorophenyl)-methoxy]ethyl]-1-(3-phenylpropyl)piperidine, 1b, were made and biologically evaluated for their binding at the DA and serotonin (5HT) transporters in rat striatal membranes. Different alkyl chain lengths and substitutions were introduced in these molecules to generate an optimum activity and selectivity for the DA transporter. In general, unsubstituted and fluoro-substituted compounds were the most active and selective for the DA transporter. The compound 4-[2-(diphenylmethoxy)ethyl]-1-benzylpiperidine, 9a, showed high potency and was the most selective for the DA transporter (5HT/DA = 49) in this series of compounds. Some of these novel analogs were found to be more selective in binding at the DA transporter than the original GBR 12909 molecule, 1-[2-]bis(4-fluorophenyl)methoxy]ethyl]-4-(3- phenylpropyl)piperidine.
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1053
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Xu C, Shi W, Rosen BP. The chromosomal arsR gene of Escherichia coli encodes a trans-acting metalloregulatory protein. J Biol Chem 1996; 271:2427-32. [PMID: 8576202 DOI: 10.1074/jbc.271.5.2427] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Plasmid-encoded arsenical resistance (ars) operons confer high level resistance to arsenicals and antimonials, while the chromosomally encoded ars operon of Escherichia coli bestows low level resistance. The transcriptional start site of the chromosomal ars mRNA was mapped by primer extension, and putative -10 and -35 promoter recognition sites were identified. The arsR gene, the first gene in this operon, was cloned using polymerase chain reaction. The arsR gene product, the ArsR repressor, was expressed and purified. The results of gel mobility shift assays indicated that the repressor is a DNA binding protein that binds to a fragment of DNA containing the chromosomal ars promoter. The specific binding site, as determined by DNase I footprint analysis, spans 33 nucleotides in the promoter region, including the putative -35 promoter element. By construction and expression of a series of in-frame fusions between truncated arsR genes and the coding region for the mature form of beta-lactamase (blaM'), it was shown that ArsR is a trans-acting repressor that regulates expression of the chromosomal ars operon. In addition, the chromosomally-encoded repressor can regulate expression of the ars operon of plasmid R773, and the R773 repressor can cross-regulate expression from the chromosomal operon.
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1054
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Xu C, Johnson JE, Singh PK, Jones MM, Yan H, Carter CE. In vivo studies of cadmium-induced apoptosis in testicular tissue of the rat and its modulation by a chelating agent. Toxicology 1996; 107:1-8. [PMID: 8597027 DOI: 10.1016/0300-483x(95)03195-l] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In vivo CdCl2-induced apoptotic DNA fragmentation in the testes of the male Wistar rat has been demonstrated on agarose gel. Characteristic DNA migration patterns (laddering) provide evidence of apoptosis (programmed cell death) in testicular tissue of rats administered CdCl2 at a level of 0.03 mmol/kg 48 h previously. Evidence that administration of an appropriate cadmium chelating agent within the first 24 h can suppress some or all of the apoptotic changes in testicular DNA has also been obtained for the first time. A greater reduction in apoptosis is observed as the interval between the administration of the cadmium and that of the chelating agent is shortened. Administration of monoisoamyl meso-2,3-dimercaptosuccinate (Mi-ADMS) to male Wistar rats given CdCl2 is effective in the modulation of the typically apoptotic DNA fragmentation and associated histopathologic injury when the antagonist is given within approximately 1 h after the CdCl2 exposure. When the antagonist is given at later times there is a progressively more pronounced degradation of the DNA into oligonucleotides as seen in the typical electrophoretic DNA ladder pattern found with apoptosis. There is also a progressive increase in histopathological tissue changes as the antagonist is administered at progressively greater intervals after the cadmium.
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1055
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Xu C, McGrane MM. Effects of hyperthyroidism on expression of a phosphoenolpyruvate carboxykinase/bovine growth hormone gene in transgenic mice. Biochem Biophys Res Commun 1996; 218:473-9. [PMID: 8561780 DOI: 10.1006/bbrc.1996.0084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Thyroid hormone (T3) responsiveness of the PEPCK promoter in vivo was examined in both PEPCK/bGH(460) and PEPCK/bGH(335) mouse lines. Transgenic and non-transgenic littermates were treated with methimazole or PTU for 6 or 4 weeks, respectively, then treated +/- T3 for 10 days. In PEPCK/bGH(460) and PEPCK/bGH(355) transgenic mice, the bGH mRNA was decreased by 65% and 46%, respectively, in hyperthyroid mice when compared to euthyroid controls. Endogenous PEPCK mRNA was decreased by 33% in hyperthyroid non-transgenic mice. The conclusion of this study is that chronic hyperthyroidism in mice inhibits PEPCK-directed expression of the transgene when either the -460/+73 or the -355/+73 promoter/regulatory elements are used.
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1056
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Ma TH, Xu C, Liao S, McConnell H, Jeong BS, Won CD. In situ monitoring with the Tradescantia bioassays on the genotoxicity of gaseous emissions from a closed landfill site and an incinerator. Mutat Res 1996; 359:39-52. [PMID: 8569801 DOI: 10.1016/s0165-1161(96)90008-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A dual monitoring system composed of the Tradescantia-Micronucleus (Trad-MCN) and Tradescantia-Stamen-Hair-Mutation (Trad-SHM) bioassays was utilized to monitor directly the genotoxicity of the gaseous emission at a closed landfill site and around an incinerator. Four of the commonly emitted gaseous agents from the landfill flare pipes, i.e. toluene, ethylbenzene, trichloroethylene and ethyltoluene were also evaluated for their genotoxicity in the laboratory. The in situ monitoring trips (360 km one way) were carried out by transporting the plant cuttings in a clean air box or in an air-tight plastic bag to the site and exposing these test cuttings for 5-7 h. The exposed plant samples were examined for micronuclei frequencies or the pink mutation rate after the appropriate recovery periods (24 h for MCN, 7-11 days for SHM). A total of 20 monitoring trips were made to the landfill, and 8 to the nearby surroundings (100-500 m from the chimney) of the incinerator site in a two year period. The major findings of the Trad-MCN test on the clastogenicity of the gaseous emission from the flare pipe of the landfill site showed positive responses or toxic effects in 6 out of 20 trips, and that from the incinerator showed positive responses in 5 out of the 8 trips. These positive responses were closely associated with the weather, i.e. low wind velocity, high temperature and relative humidity, and especially the distance from the chimney of the incinerator. The MCN frequencies and mutation rates of the Elementary School site (E. Sch) which is about 200 m from the fence of the landfill site were mostly negative, except the test results of three trips. Trad-SHM tests on the mutagenicity of gaseous emissions from the flare pipe of the landfill showed 12 positive responses out of 20 trials and 2 positives out of 4 trials from the incinerator gaseous emissions. The average mutation rate from 20 Trad-SHM monitoring trips is positive when the ANOVA and Dunnett's t-statistic were applied to the consolidated data. There is a significant (0.01) difference between the lab control and the gas exposed groups, and between the field control and gas exposed groups. Results of the Trad-SHM test at the E. Sch. site were mostly negative except for one trip. In general, micronuclei frequencies and mutation rates of the field control groups were relatively higher than those of the lab controls. The Trad-MCN test on pure gases showed positive responses in all 3 repeated tests on toluene (50-892 ppm). The test results of ethylbenzene yielded positive responses at 172 ppm/min and 1549 ppm/min dosages and exhibited toxicity at higher concentrations. Trad-MCN tests on trichloroethylene and ethyltoluene yielded positive responses at around 100-200 ppm/min level. Three repeated Trad-SHM tests on toluene yielded no positive response at low concentrations (4.3-12.9 ppm).
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1057
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Lu M, Xu C, Jiang B. [Accelerated streptokinase dose regimens for coronary thrombolysis]. ZHONGHUA NEI KE ZA ZHI 1996; 35:23-4. [PMID: 9275641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Forty patients entering our hospital up to 12 hours (5.1 +/- 2.8 hours) after the onset of definite acute myocardial infarction were treated with accelerated streptokinase dose regimens (1.5 million U/30 min) intravenously. The reperfusion rate of infarct-related arteries determined by clinical evidence of reperfusion was 77.5% (31/40). There was significant difference in reperfusion rates: 89.3% (25/28) among patients within 6 hours versus 50% (6/12) among patients within 6-12 hours after the onset of chest pain. Five cases (12.5%) experienced mild bleeding complications. One patient had chill. Three patients (7.5%) had hypotension (BP < or = 10.7/6.67 kPa, 1 kPa = 7.5 mmHg). The 5 week mortality was 2.5% (1/40). In conclusion, intravenous accelerated streptokinase dose regimen for coronary thrombolysis seems to improve reperfusion rate markedly without increasing adverse events such as allergic reactions, severe bleeding and hypotension.
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1058
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Mertz J, Xu C, Webb WW. Single-molecule detection by two-photon-excited fluorescence. OPTICS LETTERS 1995; 20:2532. [PMID: 19865276 DOI: 10.1364/ol.20.002532] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
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1059
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Xu C, Guild J, Webb W, Denk W. Determination of absolute two-photon excitation cross sections by in situ second-order autocorrelation. OPTICS LETTERS 1995; 20:2372. [PMID: 19865223 DOI: 10.1364/ol.20.002372] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
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1060
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Liu NJ, Xu T, Xu C, Li CQ, Yu YX, Kang HG, Han JS. Cholecystokinin octapeptide reverses mu-opioid-receptor-mediated inhibition of calcium current in rat dorsal root ganglion neurons. J Pharmacol Exp Ther 1995; 275:1293-9. [PMID: 8531095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cholecystokinin octapeptide (CCK-8) is reported to antagonize the analgesic effect produced by mu- and kappa- but not delta-opioid agonist in spinal cord. However, the mechanisms of interaction remain obscure. In the present study, whole-cell patch-clamp recording was performed on acutely isolated rat dorsal root ganglion (DRG) neurons to evaluate the effects of the highly specific mu-opioid agonist ohmefentanyl and the delta-opioid agonist DPDPE on voltage-gated calcium channels and the possible interaction between CCK-8 receptor and mu- or delta-opioid receptor. The results indicated that ohmefentanyl, but not DPDPE, can suppress the voltage-gated calcium currents elicited in DRG neurons, an effect readily reversed by naloxone or by the antiopioid peptide CCK-8. The effect of CCK-8 can in turn be abolished by the CCK-B receptor antagonist L365,260. CCK-8 used by itself has no enhancing effect, but rather a depressant effect, on calcium currents. However, used simultaneously with ohmefentanyl, CCK-8 shows a clear-cut reversal of depression of the mu-opioid. We conclude that the depressant effect produced by mu-opioid on voltage-gated calcium current in DRG neurons can be antagonized by CCK-8 through CCK-B receptor located in the same neuron. The delta-opioid DPDPE has no direct effect on the voltage-gated calcium current in DRG neurons.
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MESH Headings
- Animals
- Calcium Channel Blockers/pharmacology
- Enkephalin, D-Penicillamine (2,5)-
- Enkephalins/pharmacology
- Fentanyl/analogs & derivatives
- Fentanyl/pharmacology
- Ganglia, Spinal/cytology
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Ion Channel Gating
- Male
- Neurons/drug effects
- Neurons/metabolism
- Rats
- Rats, Wistar
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/physiology
- Sincalide/pharmacology
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1061
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Zhang Z, Xu C, Liu S, Zheng D, Li S. [The mRNA expression of CD2, CD4 and CD8 in peripheral blood lymphocytes from the patients with acute lymphoblastic leukemia and non-Hodgkin's lymphoma]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1995; 17:403-6. [PMID: 9208563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The paper for the first time reports the detection of the levels of CD2, CD4 and CD8 mRNA expression in peripheral blood lymphocytes from 9 cases with T-acute lymphoblastic leukemia (ALL) and 10 cases with T-non-Hodgkin's lymphoma (NHL) by using RNA dot blotting technique. It was found that the levels of CD2 mRNA in the two groups of patients were significantly higher than those in the normals. The ratios of the CD4 to CD8 mRNA were also increased in patients with NHL. The significance of this study was discussed.
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1062
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Lu W, Cheng Y, Dong N, Gu J, Xu C. Diaquabis(dichloroacetato)bis(1,10-phenanthroline)europium(III) Dichloroacetate and the Corresponding Erbium(III) Complex. Acta Crystallogr C 1995. [DOI: 10.1107/s0108270195004756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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1063
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Shu R, Xu C, Li L. [Chemical constituents of Cyclocarya paliurus (Batal.) Iljinsk]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1995; 20:680-1, 704. [PMID: 8737472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Four compounds were isolated from the leaves of Cyclocarya paliurus. They were identified as daucosstero, beta-L-arabopyranose, steraric acid and palmitic acid on the basis of spectral data and chemical properties. All of them were isolated from this plant for the first time.
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1064
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He GS, Xu C, Prasad PN, Reinhardt BA, Bhatt JC, McKellar R, Dillard AG. Two-photon absorption and optical-limiting properties of novel organic compounds: erratum. OPTICS LETTERS 1995; 20:1930. [PMID: 19862206 DOI: 10.1364/ol.20.001930] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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1065
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Lu W, Cheng Y, Dong N, Xu C, Chen C. Aquatris(dichloroacetato)ethanolbis(1,10-phenanthroline)lanthanum(III) and the Corresponding Samarium Complex. Acta Crystallogr C 1995. [DOI: 10.1107/s0108270194005068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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1066
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Wan X, Xu C, Ma G. [Shape memory angioembolus for varicocele]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1995; 33:566-7. [PMID: 8731882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Seven target veins (in 5 dogs) were embolized with nitinol conical rugby embolus (NT-CRE). The pathological examination showed firm impact between NT-CRE and intravenous membrane without misembolization from retrograde flow. Compact collagenous fibrous tissue was seen in and out NT-CRE on spaces. On the basis of animal experiment, 10 patients with varicocele were treated with NT-CRE. After the operation, the varicocele and symptoms disappeared and venae spermatica collapsed. The follow-up for 1.5-2.3 years showed no recurrence in the 10 patients. We consider that the therapeutic method is simple and effective for varicocele.
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1067
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Chen CF, Xu JH, Liu YC, Xu C. 2,3,5,6-Tetrachloro-4-hydroxyphenyl N-(4-Chlorophenyl)benzenecarboximidate. Acta Crystallogr C 1995. [DOI: 10.1107/s0108270195001247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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1068
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Xu C, Meikrantz W, Schlegel R, Sager R. The human papilloma virus 16E6 gene sensitizes human mammary epithelial cells to apoptosis induced by DNA damage. Proc Natl Acad Sci U S A 1995; 92:7829-33. [PMID: 7644500 PMCID: PMC41239 DOI: 10.1073/pnas.92.17.7829] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Programmed cell death (apoptosis) is a normal physiological process, which could in principle be manipulated to play an important role in cancer therapy. The key importance of p53 expression in the apoptotic response to DNA-damaging agents has been stressed because mutant or deleted p53 is so common in most kinds of cancer. An important strategy, therefore, is to find ways to induce apoptosis in the absence of wild-type p53. In this paper, we compare apoptosis in normal human mammary epithelial cells, in cells immortalized with human papilloma virus (HPV), and in mammary carcinoma cell lines expressing wild-type p53, mutant p53, or no p53 protein. Apoptosis was induced with mitomycin C (MMC), a DNA cross-linking and damaging agent, or with staurosporine (SSP), a protein kinase inhibitor. The normal and HPV-transfected cells responded more strongly to SSP than did the tumor cells. After exposure to MMC, cells expressing wild-type p53 underwent extensive apoptosis, whereas cells carrying mutated p53 responded weakly. Primary breast cancer cell lines null for p53 protein were resistant to MMC. In contrast, two HPV immortalized cell lines in which p53 protein was destroyed by E6-modulated ubiquitinylation were highly sensitive to apoptosis induced by MMC. Neither p53 mRNA nor protein was induced in the HPV immortalized cells after MMC treatment, although p53 protein was elevated by MMC in cells with wild-type p53. Importantly, MMC induced p21 mRNA but not p21 protein expression in the HPV immortalized cells. Thus, HPV 16E6 can sensitize mammary epithelial cells to MMC-induced apoptosis via a p53- and p21-independent pathway. We propose that the HPV 16E6 protein modulates ubiquitin-mediated degradation not only of p53 but also of p21 and perhaps other proteins involved in apoptosis.
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1069
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Xu C, Burnham JS, Braun RM, Goss SH, Winograd N. Tilting in the arsenic-induced c(4 x 4) reconstruction of the GaAs{001} surface. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:5172-5178. [PMID: 9981702 DOI: 10.1103/physrevb.52.5172] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1070
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Liu Y, Wang W, Zhu G, Chen J, Xu C. [The role of substance P in immunosuppression induced by Tripterygium wilfordii]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1995; 17:269-73. [PMID: 8575048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of T II (extracted from Tripterygium wilfordii) and substance P (SP) on imunoregulation were investigated. It has been shown that Tripterygium wilfordii is an immunosuppresive. In order to assess the immunosuppression elicited by T II was mediated by SP in spinal dorsal horn, Wistar rats were injected intrathecally with capsaicin (CAP) to deplete SP in spinal dorsal horn prior to T II given orally. The level of interleukin 2 (IL-2) produced by splenic lymphocytes of rats and the contents of SP in some brain areas and spinal cord in mice were assayed after T II treatment. Our findings were as follows: 1. The level of IL-2 was decreased significantly after T II treatment only. However the level of IL-2 was increased markedly after CAP was given intrathecally. Moreover, CAP administration also enhanced the level of IL-2 even in immunosuppression group induced by T II treatment. 2. SP contents in spinal cord, hypothalamus and brain stem of mice were increased dramatically during immunosuppression produced by T II. The results suggested that SP in spinal dorsal horn was involved in regulation of cellular immunity, the suppressive effect of T II on cellular immunity might be mediated by SP in spinal dorsal horn.
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1071
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Guo J, Wang J, Xu C. [Variant gap phenomenon in A-V conduction]. ZHONGHUA YI XUE ZA ZHI 1995; 75:494-7, 512. [PMID: 7584575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In 361 consecutive patients 4 with variant gap phenomenon (VGP) underwent intracardiac electrophysiological studies. The premature atrial response initially delayed in His-Purkinje system (HPS) which had a long relative refractory period (RRP), and H-V interval was prolonged. However, as atrial responses were more premature, the atrioventricular node (AVN) showed RRP and slowed down the conduction, that made HPS get rid of RRP before the response arriving. Thus the conduction resumed, and H-V interval became normal. It was different from the classic gap phenomenon. We call it variant gap phenomenon.
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1072
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Shen D, Xu C, Tian Y. [Value of dobutamine technetium-99m-MIBI SPECT in detecting coronary artery disease]. ZHONGHUA NEI KE ZA ZHI 1995; 34:452-5. [PMID: 8556925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The value of dobutamine 99mTc-MIBI SPECT (Dobu-ECT) for detecting coronary artery disease (CAD) was assessed in 39 patients. Compared with coronary angiography, the overall sensitivity and specificity of Dobu-ECT for detecting CAD were 92.9% and 90.9%. Of 13 patients with CAD without myocardial infarction, the sensitivity of Dobu-ECT was 84.6%. In detecting CAD with single, double or triple vessel diseases, the sensitivity of Dobu-ECT was 90.9%, 87.5% and 100% respectively. Furthermore, 88.2% of the patients (15/17) with multivessel (two or three vessels) diseases were correctly identified as having multivessel involvement. For detecting CAD, the sensitivity and specificity of dobutamine ECG were 53.5% and 82%. No serious side effects were observed in the study. The results showed that Dobu-ECT is a feasibie, safe and noninvasive method for diagnosing CAD.
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1073
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Xu C, Holscher MA, Jones MM, Singh PK. Effect of monoisoamyl meso-2,3-dimercaptosuccinate on the pathology of acute cadmium intoxication. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1995; 45:261-77. [PMID: 7609002 DOI: 10.1080/15287399509531995] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The ability of monoisoamyl meso-2,3-dimercaptosuccinate (Mi-ADMS) to offset the characteristic organ pathology of intraperitoneally administered cadmium chloride (CdCl2) and that of the cadmium-cysteine complex has been examined in male Wistar rats. The tissues examined for damage were the testes, kidney, liver, pancreas, and bone marrow. At a high dose of CdCl2 (0.03 mmol/kg, ip) testicular damage was completely prevented by Mi-ADMS (0.50 mmol/kg, ip) given immediately. A decrease in the protective ability of the antagonist was observed following delayed administration of Mi-ADMS given at 1, 2, 4, and 24 h post CdCl2. At a lower dose of CdCl2 (0.006 mmol/kg, ip), Mi-ADMS furnished essentially full protection from testicular damage when given (0.50 mmol/kg, sc) at 0 and 1 h after CdCl2. The administration of cadmium-cysteine complex (0.01 mmol/kg, ip) induced notable renal tubular damage, which was antagonized by the administration of Mi-ADMS (0.50 mmol/kg, ip) as late as 4 h after the complex. At a 24-h delay, extensive tubular necrosis was found on sacrifice after 4 d. The administration of cadmium-cysteine complex ip reduced, but did not eliminate, the characteristic damage of the seminiferous tubules found for cadmium alone. There is a progressive reduction of testicular weight as the interval between cadmium and antagonist administration increases. The average kidney weights of the animals given CdCl2-cysteine complex were increased in comparison to normal controls. The antagonistic effects of Mi-ADMS treatment on cadmium intoxication in the kidneys and the testes of rats is very similar to that found for effective dithiocarbamate antagonists. In order to obtain complete protection of the testes from the deteterious effects of cadmium, such antagonists must be administered no later than about 1 h after the cadmium.
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1074
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Wu Y, Zeng M, Xu C, Liang J, Wang Y, Miao L, Xiao K. [Analyses of the prevalences for neural tube defects and cleft lip and palate in China from 1988 to 1991]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1995; 26:215-9. [PMID: 7490034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This paper reports the monitoring results of two main categories of birth defects-neural tube defects (NTD) and cleft of lip and palate (CLP) in China during the period of continuous monitoring (1988-1991). The method of hospital-based monitoring was adopted for data collection. From Jan. 1988 to Dec. 1991, a total of 2,750,588 births were monitored, and 28,168 cases of congenital malformations were identified. The prevalence of total birth defects was 102.4 per 10,000. 6885 cases of NTD were identified during this period, the prevalence of NTD being 25.0 per 10,000. The prevalence of NTD varied geographically; it declined gradually from the north to the south of China with the highest rate of NTD in the Taihang Mountain Regions. A total of 4548 cases of CLP were identified, and the provincial prevalence of CLP varied from 11.2 to 25.7 per 10000 with a mean of 16.5 per 10000. The prevalence of NTDs varied seasonally with the peak in winter (January). The sex ratio of NTD was 0.59, the prevalences in female births (32.1 per 10,000) being higher than that in male births (17.4 per 10,000) (P < 0.01). The sex ratio of CLP was 1.33. A significant difference was noted between the sex ratio of cleft palate (0.80) and that of the total cleft lip (1.46) (P < 0.01). The prevalence of NTD in rural areas (44.3 per 10,000) was 3 times as high as that in urban areas (14.4 per 10,000), but no difference in occurrence of CLP was observed between the urban and rural areas (P > 0.05).
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1075
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Samatey FA, Xu C, Popot JL. On the distribution of amino acid residues in transmembrane alpha-helix bundles. Proc Natl Acad Sci U S A 1995; 92:4577-81. [PMID: 7753846 PMCID: PMC41987 DOI: 10.1073/pnas.92.10.4577] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The periodic distribution of residues in the sequence of 469 putative transmembrane alpha-helices from eukaryotic plasma membrane polytopic proteins has been analyzed with correlation matrices. The method does not involve any a priori assumption about the secondary structure of the segments or about the physicochemical properties of individual amino acid residues. Maximal correlation is observed at 3.6 residues per period, characteristic of alpha-helices. A scale extracted from the data describes the propensity of the various residues to lie on the same or on opposite helix faces. The most polar face of transmembrane helices, presumably that buried in the protein core, shows a strong enrichment in aromatic residues, while residues likely to face the fatty acyl chains of lipids are largely aliphatic.
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1076
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Ma TH, Xu Z, Xu C, McConnell H, Rabago EV, Arreola GA, Zhang H. The improved Allium/Vicia root tip micronucleus assay for clastogenicity of environmental pollutants. Mutat Res 1995; 334:185-95. [PMID: 7885371 DOI: 10.1016/0165-1161(95)90010-1] [Citation(s) in RCA: 214] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The meristematic mitotic cells of plant roots are appropriate and efficient cytogenetic materials for the detection of clastogenicity of environmental pollutants, especially for in situ monitoring of water contaminants. Among several cytological endpoints in these fast dividing cells, such as chromosome/chromatid aberrations, sister-chromatid exchanges and micronuclei, the most effective and simplest indicator of cytological damage is micronucleus formation. Although the Allium cepa and Vicia faba root meristem micronucleus assays (Allium/Vicia root MCN) have been used in clastogenicity studies about 12 times by various authors in the last 25 years, there is no report on the comparison of the efficiency of these two plant systems and in different cell populations (meristem and F1) of the root tip as well as under adequate recovery duration. In order to maximize the efficiency of these bioassays, the current study was designed to compare the Allium and the Vicia root MCN assays on the basis of chromosome length, peak sensitivity of the mitotic cells, and the regions of the root tip where the MCN are formed. The total length of the 2n complement of Allium chromosomes is 14.4 microns and the total length of the 2n complement of Vicia is 9.32 microns. The peak sensitivity determined by serial fixation at 12-h intervals after 100 R of X-irradiation is 44 h. The slope of the X-ray dose-response curve of Allium roots derived from the meristematic regions was lower than that derived from cells in the F1 region. Higher efficiency was also demonstrated when the MCN frequencies were scored from the F1 cells in both Allium and Vicia treated with formaldehyde (FA), mitomycin C (MMC), and maleic hydrazide (MH). The results indicated that scoring of MCN frequencies from the F1 cell region of the root tip was more efficient than scoring from the meristematic region. The X-ray linear regression dose-response curves were established in both Allium and Vicia cell systems and the coefficients of correlations, slope values were used to verify the reliability and efficiency of these two plant cell systems. Based on the dose-response slope value of 0.894 for Allium and 0.643 for Vicia, the Allium root MCN was a more efficient test system. The greater sensitivity of the Allium roots is probably due to the greater total length of the diploid complement and the higher number of metacentric chromosomes.(ABSTRACT TRUNCATED AT 400 WORDS)
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1077
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Xu C, Xu H, Cheng S. [14C-urea breath test in the diagnosis of Helicobacter pylori infection in the stomach]. ZHONGHUA NEI KE ZA ZHI 1995; 34:239-42. [PMID: 7587602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We developed a modified 14C-urea breath test (14C-UBT) to diagnose Helicobacter pylori (Hp) infection in 70 patients in which subjects were given 92.5 kBq (2.5 microCi) 14C-urea with 25 mg nonradioactive urea, without nutrient-dense meal. Using the mean value +3s as a cutoff value, the 20 min sample gave a sensitivity of 97.36%, a specificity of 90.00%, a positive predictive value of 97.36%, and a negative predictive value of 90.0%. Our data showed: (1) A satisfying accuracy of the modified 14C-UBT for the detection of Hp infection was obtained. (2) Taking 92.5 kBq (2.5 microCi) 14C-urea and 20 min collected sample may be of great use and to replace the previous big dose and long time methods. (3) This test may be applied routinely as a noninvasive, accurate, low cost, safe and rapid method. (4) It played an important role in reflecting the susceptibility of Hp to various drugs in vivo and monitoring the recurence of Hp.
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1078
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Min J, Arganoza MT, Ohrnberger J, Xu C, Akins RA. Alternative methods of preparing whole-cell DNA from fungi for dot-blot, restriction analysis, and colony filter hybridization. Anal Biochem 1995; 225:94-100. [PMID: 7778791 DOI: 10.1006/abio.1995.1113] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
There is a large and increasing number of methods for preparing whole-cell DNA from fungi. Modifications have evolved for two reasons. This first is to simplify the protocol as much as possible to allow processing of large sample numbers, in some cases for very specific uses, e.g., dot-blots. The second is to increase the quality of the DNA. Most preparations are contaminated with varying amounts of polysaccharides and unknown wall contaminants that can inhibit subsequent restriction or ligation. The extent of contamination varies with the species, the individual isolate, and at least in Neurospora, with the method or extent of growth. This paper offers three new methods. The first is a simplified procedure for isolating denatured DNAs from filamentous fungi for dot-blot analysis. The second is a rapid method for isolating DNAs from large numbers of small- to medium-scale cultures of filamentous fungi. These preparations are sufficiently pure for a variety of enzymatic reactions. The third is a nonenzymatic method for yeast colony filter hybridization that is simple, inexpensive, and efficient and results in uniform signals for a variety of species.
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1079
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Guan D, Wang R, Lu J, Wang M, Xu C. The therapeutic window of cyclosporine in Chinese recipients of renal transplantation. Transplant Proc 1995; 27:850-1. [PMID: 7879203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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1080
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Xu C, Coffey LL, Reith ME. Translocation of dopamine and binding of 2 beta-carbomethoxy-3 beta-(4-fluorophenyl) tropane (WIN 35,428) measured under identical conditions in rat striatal synaptosomal preparations. Inhibition by various blockers. Biochem Pharmacol 1995; 49:339-50. [PMID: 7857321 DOI: 10.1016/0006-2952(94)00485-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Translocation of [3H]dopamine and binding of 2 beta-carbomethoxy-3 beta-(4-fluorophenyl)[3H]-tropane ([3H]WIN 35,428) were measured in crude synaptosomal preparations from rat striatum under identical conditions of assay buffer (phosphate-Krebs) and temperature (25 degrees). [3H]Dopamine uptake as a function of time was close to linear for at least 8 min, whereas [3H]WIN 35,428 binding had reached equilibrium within 1 min and remained at its plateau value for at least 20 min. The following inhibitors were tested in uptake and binding assays run in parallel with the same synaptosomal preparation: cocaine, WIN 35,428, benztropine, nomifensine, mazindol, methylphenidate, N-[1-(2-benzo[b]-thiophenyl)cyclohexyl]piperidine (BTCP), Lu 19-005 (Indatraline), 1-(2-(di(4-fluorophenyl)-methoxy)-ethyl)-4-(3-phenyl-2-propyl)piperazine (GBR 12909), 1-(2-(diphenylmethoxy)-ethyl)-4-(3-phenyl-2-propyl)piperazine (GBR 12935) and 7-trifluoromethyl-4-(4-methyl-1-piperazinyl)-pyrrolo [1,2-a]quinoxaline (CGS 12066B). When present together with [3H]dopamine or [3H]WIN 35,428 for 8 min, the observed binding IC50 values were generally higher (average 1.4-fold) than the uptake IC50 values, with a significant y-axis intercept in linear regression analysis of binding on uptake IC50. For slowly equilibrating inhibitors, estimates of uptake IC50 values were overestimates, and relatively lower values were obtained by monitoring [3H]dopamine uptake for 1 min only during the last minute of the 8-min presence of inhibitor; under these conditions, binding over uptake IC50 ratios were on the average 2.3. Kinetic calculations, taking into account both radioligand and inhibitor equilibration kinetics, indicated that the latter comparison between binding and uptake measurements was most relevant, and suggested the involvement of complexities beyond simple competitive inhibition of dopamine transport, such as different binding domains for substrate and blocker recognition, or spare receptors for blockers. The present data indicate that binding over uptake IC50 ratios should be interpreted with caution, depending on the experimental conditions used to measure these ratios.
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1081
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Xu C, Chen Y, Lu M. [A clinical study on limitation of infarct size by ischemic preconditioning in 100 cases of acute myocardial infarction]. ZHONGHUA NEI KE ZA ZHI 1995; 34:16-8. [PMID: 7600872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The protective effect of ischemic preconditioning has been confirmed in animal models. In this study we analyzed the clinical data of 110 cases of acute myocardial infarction (77 male, 33 female). Sixty-nine cases (group A) had ischemic manifestations prior to myocardial infarction, while forty one (group B) did not have. Our data showed that the clinical features in group B were quite different as compared with those in group A: (1) larger infarct size (ratio between necrotic size and ischemic size: 71.55 +/- 3.70 to 41.65 +/- 3.96, P < 0.0001); (2) higher peak level of serum cardiac enzymes (CPK: 2085.78 +/- 265.57 to 1329.80 +/- 189.44, P < 0.01; CK-MB: 102.73 +/- 12.47 to 47.38 +/- 8.83, P < 0.01); (3) poorer cardiac function [LVEF < 0.45: 12/41 (29.3%) to 6/69 (8.7%), P < 0.05]; (4) higher incidence of left ventricular aneurysm [9/41 (22.0%) to 3/69 (4.3%), P < 0.05] and (5) higher mortality rate in 4 weeks [6/41 (14.6%) to 2/69 (2.9%), P < 0.05]. The difference between the two groups is statistically significant. In addition, the effect of the duration of preconditioning on protection of myocardium, the potential mechanism of preconditioning and its clinical significance were discussed.
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1082
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Mohsenzadeh S, Xu C, Fracella F, Rensing L. Heat shock inhibits and activates different protein degradation pathways and proteinase activities in Neurospora crassa. FEMS Microbiol Lett 1994; 124:215-24. [PMID: 7813891 DOI: 10.1016/0378-1097(94)90252-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In Neurospora crassa, heat shock treatment inhibits proteolytic activity. ATP-independent proteinases were analysed after polyacrylamide gel electrophoresis using renaturing gelatine gels. Proteinases of 24, 29, and 130 kDa were shown to be inhibited by heat shock and were further characterized as to their properties. A major part of the heat shock-induced inhibition is probably due to suppression of de novo synthesis of proteinases as deduced from experiments with cycloheximide. During several hours of recovery from heat shock, the inhibition of overall protein degradation and ATP-independent proteinases is reversed. Azocasein assays as well as pulse-chase experiments further showed that ATP-dependent protein degradation is only slightly affected by heat shock. Two ATP-binding proteinases of about 60 and 160 kDa even show an increased activity after heat shock. The degradation rate of heat shock proteins is inhibited by heat shock treatment, indicating that they are degraded by ATP-independent proteinases. Western blot analysis of a approximately 40-kDa degradation product of HSP70 containing its amino terminal portion revealed a reduction in the amount of this peptide after heat shock.
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1083
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Bai N, Xu Y, Qin L, Xu C. Design of a cryogenic videocamera-recorder and image processing system and calculation of volumes of red cells. Cryobiology 1994; 31:549-56. [PMID: 7835054 DOI: 10.1006/cryo.1994.1066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Since Rowe reported that the storage technique for red cells at very low temperatures had been realized successfully, many experts who work in the fields of cryobiology and medicine have turned their attention to this storage technique for tissues and organs. Since the first quantitative cryomicroscope was made successfully about 20 years ago, it has been possible to observe changes in shape and phase. Particularly the image processing technique has laid the foundation for quantitative analysis of the relationship between changes in shape and damage from freezing of cells and cooling rate and storage temperature. In this work, we constructed a system consisting of a cryomicroscope, a videocamera-recorder, and an image processor. We carried out many experiments with red cells in cold storage and have established a model for calculating the volumes of red cells. In our experiments we also dynamically traced the shape changes of cells with various experimental parameters.
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1084
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Fowell R, Xu C. The use of the cracked Brazilian disc geometry for rock fracture investigations. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0148-9062(94)90001-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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1085
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Xu C, Rigney DR, Anderson DJ. Two-dimensional electrophoretic profile of human sperm membrane proteins. JOURNAL OF ANDROLOGY 1994; 15:595-602. [PMID: 7721662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to characterize highly enriched human spermatozoa membrane proteins by two-dimensional electrophoresis and computer image analysis. Sperm membrane proteins were extracted by detergent solubilization from three different preparations: 1) washed semen cells following centrifugation and three wash steps in Ham's F-10 medium (the standard sperm preparation, which is contaminated with seminal immature germ cells, white blood cells, and acellular material), 2) the motile sperm fraction following centrifugation of diluted semen cells through a Percoll density gradient to enrich (> 98%) the viable mature sperm population, and 3) sperm membrane vesicles isolated from Percoll-purified motile mature sperm by nitrogen cavitation followed by differential centrifugation. The two-dimensional gel profiles of extracts of washed semen cells and motile spermatozoa contained more than 600 protein spots between pH 4 and 7 and apparent molecular mass ranging from 7.9 to 93.5 kDa. Only 73% of the major proteins in these two samples matched by computer image analysis. The highly enriched sperm membrane vesicle extract showed a much simpler protein pattern, with only 64 major protein spots, 61 of which could be matched with proteins detected in extracts from purified motile sperm. The isoelectric point and molecular weight coordinates of these major human sperm membrane proteins could serve as a foundation for systematic isolation and further characterization of human sperm antigens for studies of mechanisms of fertilization and the development of contraceptive vaccines.
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1086
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Tan H, Xu C, Tian Y, Xu J, Chater KF. [The effect of a promoter P28-1 of Bacillus subtilis on Streptomyces differentiation]. WEI SHENG WU XUE BAO = ACTA MICROBIOLOGICA SINICA 1994; 34:339-344. [PMID: 7871778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A 1.1kb promoter P28-1 was inserted into pUC19. After then, the P28-1 was subcloned into the HindIII-EcoRI sites of the high copy number Streptomyces promoter probe plasmid pIJ4083 containing xy1E reporter gene. This recombinant plasmid was designated as pIJ4498. When pIJ4498 was introduced into Streptomyces coelicolor J1501 protoplasts, transformants conferred a white phenotype, whereas the vector pIJ4083 gave rise to colonies of normal, dark grey appearance which is the same as that of J1501 itself. After confirming pIJ4498 structure with some restriction enzymes, it was also introduced into whiG mutant (C71). Crude enzyme extracts were isolated from J1501/pIJ4498, J1501/pIJ4083 and C71/pIJ4498 respectively, the crude enzyme extract from J1501/pIJ4498 could oxidize catechol (colourless) to 2-hydroxy muconic semialdehyde (yellow colour), but crude enzyme extracts from J1501/pIJ4083 and C71/pIJ4498 could not oxidize catechol to 2-hydroxymuconic semialdehyde. The results indicated that P28-1 might be recognised by sigma whiG RNA polymerase, and activated the xylE reporter gene expression and reduced J1501 sporulation.
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1087
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Zhao J, Xu C, Wang N. [Epidemiological study on the infections of Mycoplasma and Chlamydia in immoral persons and healthy controls in seven areas of China]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 1994; 15:263-6. [PMID: 7859257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
1,284 immoral persons and 1,161 healthy controls, from seven areas of China, were detected for the antibodies to Ureaplasma urealyticum (Uu), Mycoplasma hominis (Mh), and Chlamydia trachomatis (Ct) by indirect hemoagglutination (IHA). The results showed that: (1) in the immoral persons, the positive rates of antibody was the highest in Uu (25.47%), higher in Ct (18.22%), and lower in Mh (8.80%); (2) the levels of antibody to Mh, Uu, and Ct were significantly higher in the immoral persons than in the healthy controls; and (3) the immoral persons were commonly complicated with infections caused by Uu and Ct. It was indicated that the immoral persons were risk population of Mycoplasma and/or Chlamydial veneral diseases, and it must be noted for us controlling veneral diseases.
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1088
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Moore JE, Xu C, Glagov S, Zarins CK, Ku DN. Fluid wall shear stress measurements in a model of the human abdominal aorta: oscillatory behavior and relationship to atherosclerosis. Atherosclerosis 1994; 110:225-40. [PMID: 7848371 DOI: 10.1016/0021-9150(94)90207-0] [Citation(s) in RCA: 256] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Clinically significant atherosclerosis in the human aorta is most common in the infrarenal segment. This study was initiated to test the hypothesis that flowfield properties are closely related to the localization of plaques in this segment of the arterial system. Wall shear stress was calculated from magnetic resonance velocity measurements of pulsatile flow in an anatomically accurate model of the human abdominal aorta. The wall shear stress values were compared with intimal thickening from 15 post-mortem aortas measured by quantitative morphometry of histological cross sections obtained at standard locations. Wall shear stress oscillated in direction throughout most of the infrarenal aorta, most prominently in the distal region. The time-averaged mean wall shear stress (-1.7 to 1.4 dyn/cm2) was lowest near the posterior wall in this region. These hemodynamic parameters coincided with the locations of maximal intimal thickening. Statistical correlation between oscillatory shear and intimal thickness yielded r = 0.79, P < 0.00001. Low mean shear stresses correlated nearly as well (r = -0.75, P < 0.00005). Comparison of our data with surface maps of Sudan Red staining and early lesions as reported by others revealed similar conclusions. In contrast, pulse and maximum shear stresses did not correlate with plaque localization as has been shown for other sites of selective involvement by atherosclerosis (r < 0.345). Simulated exercise conditions markedly changed the magnitude and pattern of wall shear stress in the distal abdominal aorta. These results demonstrate that in the infrarenal aorta, regions of low mean and oscillating wall shear stresses are predisposed to the development of plaque while regions of relatively high wall shear stress tend to be spared.
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1089
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Singh PK, Xu C, Jones MM, Kostial K, Blanusa M. Molecular-modeling design of cadmium-mobilizing agents: a novel biscarbodithioate. Chem Res Toxicol 1994; 7:614-20. [PMID: 7841339 DOI: 10.1021/tx00041a005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This report describes the design, synthesis, characterization, and in vivo cadmium-mobilizing properties of a novel biscarbodithioate chelating agent, namely, disodium N,N'-diglucosyl-1,9-nonanediamine-N,N'-biscarbodithioate+ ++ (C9G2DTC), HOCH2(CHOH)4CH2(CS2Na)N(CH2)9N(CS2-Na)CH2( CHOH)4CH2OH, which can coordinate to a single cadmium ion with both of its carbodithioate groups (CS2Na) in its folded configuration. When evaluated for its cadmium efficacy at 1.0 mmol/kg x 5 ip in 109Cd-pretreated rats against sodium N-benzyl-D-glucamine-N-carbodithioate (BGDTC) as standard, the biscarbodithioate was found to reduce the whole-body levels of cadmium more rapidly in the rat than BGDTC which contains only one CS2Na group. The whole-body Cd depletions after the first ip injection of the new and the standard compound were 52% and 23%, respectively. The C9G2DTC was found to be more effective in removing cadmium from the liver (% Cd reductions compared to controls: C9G2DTC, 94, and BGDTC, 85), but slightly less effective in reducing renal cadmium levels (% Cd-reductions: C9G2DTC, 44, and BGDTC, 60). The ip LD50 of the bis-DTC was estimated to be slightly in excess of ca. 4.0 mmol/kg in the rat. A molecular model of this chelating agent indicates that, because of the flexibility of the nonane chain, both carbodithioate groups can approach closely enough to each other to permit complexation with the same cadmium ion to give a resulting structure without significant strain. A mechanism for the removal of Cd from CdMT by C9G2DTC is also proposed.
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1090
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Roger C, Corbitt T, Xu C, Zeng D, Powell Q, Chandler C, Nyman M, Hampden-Smith M, Kodas T. Principles of molecular precursor selection for aerosol synthesis of materials. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0965-9773(94)90060-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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1091
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Singh I, Xu C, Pettegrew JW, Kanfer JN. Endogenous inhibitors of human choline acetyltransferase present in Alzheimer's brain: preliminary observation. Neurobiol Aging 1994; 15:643-9. [PMID: 7824057 DOI: 10.1016/0197-4580(94)00059-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have previously demonstrated the presence in Alzheimer's disease brain of an endogenous inhibitor of choline acetyltransferase activity. Selected properties of these compounds were investigated. There appear to be two distinct classes of inhibitor present, both phosphomonoesters and nonphosphorylated substances. They are not proteins, pass through 500 mm dialyses membranes and are not lipoidal. There are both different sensitivities of individual control cytosotic activity to inhibition and differences in intrinsic inhibitory activity present in individual Alzheimer's disease brain samples. There is a competitive type of inhibition with respect to acetyl CoA as substrate and a noncompetitive type with respect to choline as substrate.
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1092
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Reith ME, Coffey LL, Xu C, Chen NH. GBR 12909 and 12935 block dopamine uptake into brain synaptic vesicles as well as nerve endings. Eur J Pharmacol 1994; 253:175-8. [PMID: 8013544 DOI: 10.1016/0014-2999(94)90774-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
GBR 12909 and 12935, commonly used as potent neuronal dopamine uptake blockers, also inhibit dopamine uptake into brain synaptic vesicles. The concentrations required for the latter activity (34-45 nM) are one order of magnitude higher than those required for inhibiting neuronal uptake of dopamine (1-6 nM). In contrast, the two activities differ by three orders of magnitude for cocaine (137 microM versus 0.35 microM). We propose that the vesicular effect of GBR-type dopamine uptake blockers should be taken into account when interpreting in vivo experiments.
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1093
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Stoeger WR, Ellis GF, Xu C. Observational cosmology. VI. The microwave background and the Sachs-Wolfe effect. Int J Clin Exp Med 1994; 49:1845-1853. [PMID: 10017168 DOI: 10.1103/physrevd.49.1845] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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1094
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Xu C, Burnham JS, Goss SH, Caffey K, Winograd N. Oxygen-induced near-surface structural rearrangements on Ni{001} studied by shadow-cone-enhanced secondary-ion mass spectrometry. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:4842-4849. [PMID: 10011415 DOI: 10.1103/physrevb.49.4842] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1095
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Xu C, Scuseria GE. Tight-binding molecular dynamics simulations of fullerene annealing and fragmentation. PHYSICAL REVIEW LETTERS 1994; 72:669-672. [PMID: 10056493 DOI: 10.1103/physrevlett.72.669] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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1096
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Damour T, Soffel M, Xu C. General-relativistic celestial mechanics. IV. Theory of satellite motion. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1994; 49:618-635. [PMID: 10017023 DOI: 10.1103/physrevd.49.618] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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1097
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Neuhaus-Steinmetz U, Xu C, Fracella F, Oberheitmann B, Richter-Landsberg C, Rensing L. Heat shock response and cytotoxicity in C6 rat glioma cells: structure-activity relationship of different alcohols. Mol Pharmacol 1994; 45:36-41. [PMID: 8302278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In C6 rat glioma cells, the n-alcohols methanol, ethanol, propanol, and butanol and the aromatic alcohol phenol all induce heat shock proteins (HSPs) of high molecular mass (68, 70, 90, and 110 kDa) when applied for 1 hr. The lowest alcohol concentrations that induce HSP synthesis cause about 20% cell death, as determined by neutral red assay. HSP induction thus occurs at alcohol concentrations close to the highest tolerable dose. The cytotoxicity and the potential of alcohols to induce the synthesis of HSPs increase with chain length and are correlated with the lipophilicity of the alcohols. A clear structure-activity relationship is observed for both parameters. A calculation of the putative membrane concentrations of these alcohols reveals that cytotoxic effects (50% cell death) occur at nearly the same membrane concentration (approximately 0.2 M). This also holds true for the lowest HSP 68-inducing alcohol concentrations, but at a lower concentration (approximately 0.12 M). The activities of major proteinases are affected by both heat shock and alcohols. The effects of alcohols also depend on the lipophilicity of the alcohols. Effective concentrations again are close to the highest tolerable dose. The stress reactions measured in terms of significant changes in HSP synthesis and proteinase activity provide information about the mechanisms by which toxic agents act on the cell.
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1098
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Wu RL, Zhu G, Galvin S, Xu C, Haseba T, Chaloin-Dufau C, Dhouailly D, Wei ZG, Lavker RM, Kao WY. Lineage-specific and differentiation-dependent expression of K12 keratin in rabbit corneal/limbal epithelial cells: cDNA cloning and northern blot analysis. Differentiation 1994; 55:137-44. [PMID: 7511548 DOI: 10.1046/j.1432-0436.1994.5520137.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Corneal epithelial cells synthesize an acidic (55 kDa) K12 and a basic (64 kDa) K3 keratin as their major differentiation products during an advanced stage of differentiation. In this paper, we describe the cDNA cloning of rabbit K12 keratin. We used a 36 base pairs (bp) oligonucleotide corresponding to a consensus sequence of many known acidic keratins as a probe to screen a cDNA library of normal rabbit corneal epithelium. Several partial cDNA clones were isolated. Hybrid-selection showed that the 3'keratin chain-specific portion of the cDNA hybridizes with K12 mRNA. A rabbit antiserum raised against the C-terminus of the cDNA-deduced amino acid sequence recognizes, in immunoblotting, the K12 keratin. In situ hybridization showed that K12 mRNA is present in all cell layers of central corneal epithelium, but in only the suprabasal cells of limbal epithelium indicating a parallel expression pattern between K12 and K3. Cultured rabbit corneal epithelial cells initially synthesize K14/K5 keratins, but later when the cells become heavily stratified they synthesize large quantities of K12 and K3 mRNAs, as detected by Northern blotting. Cultured esophageal epithelial cells do not make K12 mRNA confirming the tissue-specificity of K12 expression. Although it has been suggested that conjunctival epithelial cells can trans-differentiate into a bona fide corneal epithelium, we showed here that cultured conjunctival cells do not synthesize significant amounts of K12/K3 mRNAs. These results strongly suggest that conjunctival epithelial cells, whose differentiation can be modulated significantly by the extracellular matrix, form a lineage intrinsically distinct from the corneal/limbal epithelial lineage.
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1099
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Russ H, Soffel MH, Xu C, Dunsby PK. Covariant and gauge-invariant formulation of the Sachs-Wolfe effect. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1993; 48:4552-4556. [PMID: 10016107 DOI: 10.1103/physrevd.48.4552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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1100
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Wu S, Chen J, Xu C. The role of substance P in the pathogenesis of experimental allergic neuritis. REGULATORY PEPTIDES 1993; 46:251-3. [PMID: 7692507 DOI: 10.1016/0167-0115(93)90050-i] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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