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Sun B, Shen R, Cheng S, Zhang C, Zhong J. The role of double-balloon enteroscopy in diagnosis and management of incomplete small-bowel obstruction. Endoscopy 2007; 39:511-5. [PMID: 17554645 DOI: 10.1055/s-2007-966376] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND STUDY AIMS Double-balloon enteroscopy (DBE) is a newly developed endoscopic technique for investigating various small-bowel diseases. The aim of this study was to evaluate the diagnostic yield and therapeutic impact of DBE in patients with incomplete small-bowel obstruction (SBO). PATIENTS AND METHODS This study is a prospective analysis of 45 consecutive patients specifically referred to our hospital between December 2004 and January 2006 for investigation of incomplete SBO that had been confirmed by both clinical symptoms and imaging tests. Patients with a high suspicion of postoperative adhesion were excluded and DBE was performed in stable patients. The final management was guided by the results of DBE and radiographic studies. Demographic, clinical, procedural, and outcome data were collected for analysis. RESULTS A total of 30 DBEs were performed in 29 patients (11 women, 18 men; mean age 52.0 +/- 13.5 years). DBE identified causes of incomplete SBO in 27 patients (93.1%) and allowed histopathologic evaluation in 17 patients (58.6%). The more common abnormalities detected were small-bowel tumors (48.3%) and strictures caused by Crohn's disease (24.1%). In detecting small-bowel abnormalities, DBE showed a sensitivity of 96.4%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 50%. DBE influenced the therapeutic strategy in 41.4% of patients by adding more information regarding appropriate treatment. Follow-up data were obtained for 26 patients (89.7%), for a mean 9.4 months (range 4-18 months). Of the 26 patients with follow-up, 21 (72.4%) had no further SBO. CONCLUSIONS Double-balloon enteroscopy is a feasible diagnostic tool for detecting the causes of incomplete SBO in patients without a history of abdominal surgery and also influences therapy in patients without a definite cause detected by conventional radiography.
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Zhang D, Wang L, Lv F, Su W, Liu Y, Shen R, Bi P. Advantages and challenges of using census and multiplier methods to estimate the number of female sex workers in a Chinese city. AIDS Care 2007; 19:17-9. [PMID: 17129853 DOI: 10.1080/09540120600966158] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Using census and multiplier methods to estimate the size of the population of female sex workers (FSWs) in a small city in western China, this study compared the advantages and challenges of the two methods. It was estimated that there were about 1,500 FSWs within the urban area using the census method, which was significantly lower than that estimated by the multiplier method (2,500). Each method has advantages and limitations, and could be applied to different situations. The census method is less time and resource consuming in smaller regions and has a tendency to underestimate, and therefore, the result can be viewed as a low limit. It is useful in a local setting, for example, when estimations are needed for planning HIV/AIDS prevention programmes in a single city. Using existing information or resources, multiplier method could be used to produce estimates for a large geographic area or at a national level.
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Horiguchi A, Zheng R, Goodman OB, Shen R, Guan H, Hersh LB, Nanus DM. Lentiviral vector neutral endopeptidase gene transfer suppresses prostate cancer tumor growth. Cancer Gene Ther 2007; 14:583-9. [PMID: 17415380 DOI: 10.1038/sj.cgt.7701047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Neprilysin (neutral endopeptidase, NEP) is a cell surface peptidase whose expression is lost in approximately 50% of prostate cancers (PC). NEP normally functions to inactivate peptides such as bombesin and endothelin-1, and potentiates the effects of the PTEN tumor suppressor via a direct protein-protein interaction. NEP loss contributes to PC progression. We investigated the therapeutic efficacy of using a lentiviral vector system to restore NEP expression in PC cells. Third-generation lentiviral vectors encoding wild-type NEP (L-NEP) or green fluorescent protein (L-GFP) were introduced into NEP-deficient 22RV1 PC cells. Cells infected with L-NEP or L-GFP at a multiplicity of infection of 10 demonstrated NEP enzyme activity of 1171.2+/-4.9 and 17.2+/-5.3 pmol/microg/min (P<0.0001), respectively. Cell viability, proliferation and invasion were each significantly inhibited in 22RV1 cells expressing NEP compared with control cells infected with L-GFP (P<0.01). Analysis of known downstream effects of NEP showed NEP-expressing cells exhibiting decreased Akt and focal adhesion kinase phosphorylation and increased PTEN protein expression. Finally, injection of L-NEP into established 22RV1 xenograft tumors significantly inhibited tumor growth (P<0.01). These experiments demonstrate that lentiviral NEP gene transfer is a novel targeted strategy for the treatment of NEP-deficient PC.
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Feng X, Du Y, Chen X, Shen R, Ruan S, Wu Q, Tan J. Control of hypertrophic scar from inception by using xenogenic (porcine) acellular dermal matrix (ADM) to cover deep second degree burn. Burns 2007. [DOI: 10.1016/j.burns.2006.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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80
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Gong J, Zhu J, Goodman OB, Pestell RG, Schlegel PN, Nanus DM, Shen R. Activation of p300 histone acetyltransferase activity and acetylation of the androgen receptor by bombesin in prostate cancer cells. Oncogene 2006; 25:2011-21. [PMID: 16434977 DOI: 10.1038/sj.onc.1209231] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Androgen receptor signaling in prostate cancer cells is augmented by the androgen receptor (AR) coactivator p300, which transactivates and acetylates the AR in the presence of dihydrotestosterone (DHT). As prostate cancer (PC) cells progress to androgen independence, AR signaling remains intact, indicating that other factors stimulate AR activities in the absence of androgen. We previously reported that neuropeptide growth factors could transactivate the AR in the presence of very low concentrations of DHT. Here, we examine the involvement of p300 in neuropeptide activation of AR signaling. Transfection of increasing concentrations of p300 in the presence of bombesin into PC-3 cells resulted in a linear increase in AR transactivation, suggesting that p300 acts as a coactivator in neuropeptide-mediated AR transactivation. P300 is endowed with histone acetyltransferase (HAT) activity. Therefore, we examine the effect of bombesin on p300 HAT activity. At 4 h after the addition of bombesin, p300 HAT activity increased 2.0-fold (P<0.01). Incubation with neutral endopeptidase, which degrades bombesin, or bombesin receptor antagonists blocked bombesin-induced p300 HAT activity. To explore the potential signaling pathways involved in bombesin-induced p300 HAT activity, we examined Src and PKCdelta pathways that mediate bombesin signaling. Inhibitors of Src kinase activity or Src kinase siRNA blocked bombesin-induced p300 HAT activity, whereas PKCdelta inhibitors or PKCdelta siRNA significantly increased bombesin-induced p300 HAT activity suggesting that Src kinase and PKCdelta kinase are involved in the regulation of p300 HAT activity. As AR is acetylated in the presence of 100 nM DHT, we next examined whether bombesin-induced p300 HAT activity would result in enhanced AR acetylation. Bombesin-induced AR acetylation at the same motif KLKK observed in DHT-induced acetylation. Elimination of p300 using p300 siRNA reduced AR acetylation, demonstrating that AR acetylation was mediated by p300. AR acetylation results in AR transactivation and the expression of the AR-regulated gene prostate-specific antigen (PSA). Therefore, we examined bombesin-induced AR transactivation and PSA expression in the presence and absence of p300 siRNA and found inhibition of p300 expression reduced bombesin-induced AR transactivation and PSA expression. Together these results demonstrate that bombesin, via Src and PKCdelta signaling pathways, activates p300 HAT activity which leads to enhanced acetylation of AR resulting in increased expression of AR-regulated genes.
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Zheng R, Iwase A, Shen R, Goodman OB, Sugimoto N, Takuwa Y, Lerner DJ, Nanus DM. Neuropeptide-stimulated cell migration in prostate cancer cells is mediated by RhoA kinase signaling and inhibited by neutral endopeptidase. Oncogene 2006; 25:5942-52. [PMID: 16652149 DOI: 10.1038/sj.onc.1209586] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The neuropeptides bombesin and endothelin-1 stimulate prostate cancer (PC) cell migration and invasion (J Clin Invest, 2000; 106: 1399-1407). The intracellular signaling pathways that direct this cell movement are not well delineated. The monomeric GTPase RhoA is required for migration in several cell types including neutrophils, monocytes and fibroblasts. We demonstrate that bombesin-stimulated PC cell migration occurs via the heterotrimeric G-protein-coupled receptors (G-protein) G alpha 13 subunit leading to activation of RhoA, and Rho-associated coiled-coil forming protein kinase (ROCK). Using siRNA to suppress expression of the three known G-protein alpha-subunit-associated RhoA guanine nucleotide exchange factors (GEFs), we also show that two of these RhoA GEFs, PDZ-RhoGEF and leukemia-associated RhoGEF (LARG), link bombesin receptors to RhoA in a non-redundant manner in PC cells. We next show that focal adhesion kinase, which activates PDZ-RhoGEF and LARG, is required for bombesin-stimulated RhoA activation. Neutral endopeptidase (NEP) is expressed on normal prostate epithelium whereas loss of NEP expression contributes to PC progression. We also demonstrate that NEP inhibits neuropeptide activation of RhoA. Together, these results establish a contiguous signaling pathway from the bombesin receptor to ROCK in PC cells, and they implicate NEP as a major regulator of neuropeptide-stimulated RhoA in these cells. This work also identifies members of this signaling pathway as potential targets for rational pharmacologic manipulation of neuropeptide-stimulated migration of PC cells.
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Wang X, Yu J, Sreekumar A, Varambally S, Shen R, Giacherio D, Mehra R, Montie J, Pienta K, Sanda M, Kantoff P, Rubin M, Wei J, Ghosh D, Chinnaiyan A. Autoantibody Signatures in Prostate Cancer. J Urol 2006. [DOI: 10.1016/s0022-5347(06)00094-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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83
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Choi HH, Gray PB, Storer TW, Calof OM, Woodhouse L, Singh AB, Padero C, Mac RP, Sinha-Hikim I, Shen R, Dzekov J, Dzekov C, Kushnir MM, Rockwood AL, Meikle AW, Lee ML, Hays RD, Bhasin S. Effects of testosterone replacement in human immunodeficiency virus-infected women with weight loss. J Clin Endocrinol Metab 2005; 90:1531-41. [PMID: 15613414 DOI: 10.1210/jc.2004-1677] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The objective of this study was to determine whether physiological testosterone replacement increases fat-free mass (FFM) and muscle strength and contributes to weight maintenance in HIV-infected women with relative androgen deficiency and weight loss. Fifty-two HIV-infected, medically stable women, 18-50 yr of age, with more than 5% weight loss over 6 months and testosterone levels below 33 ng/dl were randomized into this double-blind, placebo-controlled trial of 24-wk duration. Subjects in the testosterone group applied testosterone patches twice weekly to achieve a nominal delivery of 300 mug testosterone over 24 h. Data were evaluable for 44 women. Serum average total and peak testosterone levels increased significantly in the testosterone group, but did not change in the placebo group. However, there were no significant changes in FFM (testosterone, 0.7 +/- 0.4 kg; placebo, 0.3 +/- 0.4 kg), fat mass (testosterone, 0.3 +/- 0.7 kg; placebo, 0.6 +/- 0.7 kg), or body weight (testosterone, 1.0 +/- 0.9 kg; placebo, 0.9 +/- 0.8 kg) between the two treatment groups. There were no significant changes in leg press strength, leg power, or muscle fatigability in either group. Changes in quality of life, sexual function, cognitive function, and Karnofsky performance scores did not differ significantly between the two groups. High-density lipoprotein cholesterol levels decreased significantly in the testosterone group. The patches were well tolerated. We conclude that physiological testosterone replacement was safe and effective in raising testosterone levels into the mid to high normal range, but did not significantly increase FFM, body weight, or muscle performance in HIV-infected women with low testosterone levels and mild weight loss. Additional studies are needed to fully explore the role of androgens in the regulation of body composition in women.
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Fan JB, Oliphant A, Shen R, Kermani BG, Garcia F, Gunderson KL, Hansen M, Steemers F, Butler SL, Deloukas P, Galver L, Hunt S, McBride C, Bibikova M, Rubano T, Chen J, Wickham E, Doucet D, Chang W, Campbell D, Zhang B, Kruglyak S, Bentley D, Haas J, Rigault P, Zhou L, Stuelpnagel J, Chee MS. Highly parallel SNP genotyping. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2004; 68:69-78. [PMID: 15338605 DOI: 10.1101/sqb.2003.68.69] [Citation(s) in RCA: 505] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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85
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Artaza JN, Bhasin S, Shen R, Gonzalez-Cadavid N. 112 MYOSTATIN INHIBITS MYOGENESIS AND PROMOTES ADIPOGENESIS IN 10T1/2 MESENCHYMAL PLURIPOTENT CELLS. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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86
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Artaza JN, Bhasin S, Shen R, Gonzalez-Cadavid N. MYOSTATIN INHIBITS MYOGENESIS AND PROMOTES ADIPOGENESIS IN 10T1/2 MESENCHYMAL PLURIPOTENT CELLS. J Investig Med 2004. [DOI: 10.1097/00042871-200401001-00112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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87
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Choong K, Shen R. Prenatal ethanol exposure alters the postnatal development of the spontaneous electrical activity of dopamine neurons in the ventral tegmental area. Neuroscience 2004; 126:1083-91. [PMID: 15207341 DOI: 10.1016/j.neuroscience.2004.04.041] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2004] [Indexed: 10/26/2022]
Abstract
Prenatal ethanol exposure causes a persistent reduction in the spontaneous electrical activity of dopamine (DA) neurons in the ventral tegmental area (VTA) in adult animals. Because DA neuron activity matures into adult pattern during postnatal development, it is possible that reduced activity in VTA DA neurons after prenatal ethanol exposure is caused by impaired postnatal development. This possibility was investigated in the present study using the in vivo extracellular single-unit recording and brain stimulation techniques. The results show an age-dependent decrease in the number of spontaneously active VTA DA neurons from 2 to 4 weeks of age in both the control and prenatal ethanol-exposed animals. In ethanol-exposed animals, the age-dependent decrease was more prominent after 3 weeks of age, resulting in lower numbers of spontaneously active VTA DA neurons in 4-week-old and adult animals. In both the control and ethanol-exposed animals, there were age-dependent increases in the firing rates and burst firing activity of VTA DA neurons after 2 weeks of age. Ethanol exposure led to slightly lower firing rates in 4-week-old and adult animals and did not impact the burst firing pattern in any age groups. There were no changes in axon conduction velocity and antidromic spike characteristics of VTA DA neurons. These results indicate that reduced activity of VTA DA neurons during adulthood after prenatal ethanol exposure does not begin prenatally. Instead, it is a result of impaired postnatal development manifested only when animals reach 4 weeks of age. These results suggest that early intervention may be an effective treatment strategy for attention deficit/hyperactivity disorder, a behavioral dysfunction related to the abnormalities of DA systems and often observed in children with fetal alcohol spectrum disorder.
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Shen R, Zheng ZM, Xing DY. Is there coexistence of itinerant ferromagnetism and s-wave superconductivity? PHYSICAL REVIEW LETTERS 2003; 91:069702. [PMID: 12935116 DOI: 10.1103/physrevlett.91.069702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2002] [Indexed: 05/24/2023]
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89
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Bhasin S, Woodhouse L, Casaburi R, Singh AB, Bhasin D, Berman N, Chen X, Yarasheski KE, Magliano L, Dzekov C, Dzekov J, Bross R, Phillips J, Sinha-Hikim I, Shen R, Storer TW. Testosterone dose-response relationships in healthy young men. Am J Physiol Endocrinol Metab 2001; 281:E1172-81. [PMID: 11701431 DOI: 10.1152/ajpendo.2001.281.6.e1172] [Citation(s) in RCA: 544] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Testosterone increases muscle mass and strength and regulates other physiological processes, but we do not know whether testosterone effects are dose dependent and whether dose requirements for maintaining various androgen-dependent processes are similar. To determine the effects of graded doses of testosterone on body composition, muscle size, strength, power, sexual and cognitive functions, prostate-specific antigen (PSA), plasma lipids, hemoglobin, and insulin-like growth factor I (IGF-I) levels, 61 eugonadal men, 18-35 yr, were randomized to one of five groups to receive monthly injections of a long-acting gonadotropin-releasing hormone (GnRH) agonist, to suppress endogenous testosterone secretion, and weekly injections of 25, 50, 125, 300, or 600 mg of testosterone enanthate for 20 wk. Energy and protein intakes were standardized. The administration of the GnRH agonist plus graded doses of testosterone resulted in mean nadir testosterone concentrations of 253, 306, 542, 1,345, and 2,370 ng/dl at the 25-, 50-, 125-, 300-, and 600-mg doses, respectively. Fat-free mass increased dose dependently in men receiving 125, 300, or 600 mg of testosterone weekly (change +3.4, 5.2, and 7.9 kg, respectively). The changes in fat-free mass were highly dependent on testosterone dose (P = 0.0001) and correlated with log testosterone concentrations (r = 0.73, P = 0.0001). Changes in leg press strength, leg power, thigh and quadriceps muscle volumes, hemoglobin, and IGF-I were positively correlated with testosterone concentrations, whereas changes in fat mass and plasma high-density lipoprotein (HDL) cholesterol were negatively correlated. Sexual function, visual-spatial cognition and mood, and PSA levels did not change significantly at any dose. We conclude that changes in circulating testosterone concentrations, induced by GnRH agonist and testosterone administration, are associated with testosterone dose- and concentration-dependent changes in fat-free mass, muscle size, strength and power, fat mass, hemoglobin, HDL cholesterol, and IGF-I levels, in conformity with a single linear dose-response relationship. However, different androgen-dependent processes have different testosterone dose-response relationships.
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90
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Koul D, Parthasarathy R, Shen R, Davies MA, Jasser SA, Chintala SK, Rao JS, Sun Y, Benvenisite EN, Liu TJ, Yung WK. Suppression of matrix metalloproteinase-2 gene expression and invasion in human glioma cells by MMAC/PTEN. Oncogene 2001; 20:6669-78. [PMID: 11709701 DOI: 10.1038/sj.onc.1204799] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2000] [Revised: 06/07/2001] [Accepted: 06/11/2001] [Indexed: 01/21/2023]
Abstract
Human gliomas are highly invasive, and remain to be a major obstacle for any effective therapeutic remedy. Among many other factors, gliomas express elevated levels of matrix metalloproteinases (MMPs), which have been implicated to play an important role in tumor invasion as well as neovascularization. The tumor suppressor gene mutated in multiple advanced cancers/phosphatase and tensin homologue (MMAC/PTEN) has been shown to inhibit cell migration, spreading, and focal adhesion. In this study, we determined whether MMAC/PTEN inhibits tumor invasion by modulating MMP-2 activity. Our results showed that reintroduction of the MMAC/PTEN gene into human glioma U251 and U87 cells modified their phenotype and growth characteristics. The ability of MMAC/PTEN to induce anoikis in U251 cells was accompanied by a significant inhibition of in vitro invasion (70%). Expression of MMAC/PTEN in U251 and U87 cells inhibited MMP-2 enzymatic activity as determined by zymography. Furthermore, MMAC/PTEN expression strongly decreased MMP-2 mRNA levels, which correlated well with the inhibition of invasion capacity in these cells. Concomitant with MMP-2 expression and activity, MMP-2 promoter activity was also reduced in MMAC/PTEN expressing cells. Our observations suggest that MMAC/PTEN inhibits tumor cell invasion in part by regulating MMP-2 gene transcription and thereby its enzymatic activity. Further characterization of this regulation will facilitate the development of MMAC/PTEN based gene therapy for gliomas.
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91
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Tsou HR, Mamuya N, Johnson BD, Reich MF, Gruber BC, Ye F, Nilakantan R, Shen R, Discafani C, DeBlanc R, Davis R, Koehn FE, Greenberger LM, Wang YF, Wissner A. 6-Substituted-4-(3-bromophenylamino)quinazolines as putative irreversible inhibitors of the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor (HER-2) tyrosine kinases with enhanced antitumor activity. J Med Chem 2001; 44:2719-34. [PMID: 11495584 DOI: 10.1021/jm0005555] [Citation(s) in RCA: 213] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of new 6-substituted-4-(3-bromophenylamino)quinazoline derivatives that may function as irreversible inhibitors of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor (HER-2) tyrosine kinases have been prepared. These inhibitors have, at the C-6 position, butynamide, crotonamide, and methacrylamide Michael acceptors bearing water-solublilizing substituents. These compounds were prepared by acylation of 6-amino-4-(3-bromophenylamino)quinazoline with unsaturated acid chlorides or mixed anhydrides. We show that attaching a basic functional group onto the Michael acceptor results in greater reactivity, due to intramolecular catalysis of the Michael addition and/or an inductive effect of the protonated basic group. This, along with improved water solubility, results in compounds with enhanced biological properties. We present molecular modeling and experimental evidence that these inhibitors interact covalently with the target enzymes. One compound, 16a, was shown to have excellent oral activity in a human epidermoid carcinoma (A431) xenograft model in nude mice.
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92
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Shen R, Ma JF. Distribution and mobility of aluminium in an Al-accumulating plant, Fagopyrum esculentum Moench. JOURNAL OF EXPERIMENTAL BOTANY 2001; 52:1683-1687. [PMID: 11479333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Buckwheat (Fagopyrum esculentum Moench. cv. Jianxi) accumulates high concentrations of Al in the leaves without showing any toxicity. To understand the accumulation mechanism of Al in buckwheat, the distribution and mobility of Al in buckwheat were investigated. Relatively long-term treatment (28 d) with Al led to a decrease in Al concentration from old to young leaves, while a short-term (1 d) exposure to Al resulted in a uniform distribution of Al in the leaves. When the fourth leaf was wrapped inside a transparent plastic bag to suppress transpiration, the Al concentration of this leaf was only one-quarter of that in the corresponding leaf without wrapping. Within a leaf, the Al concentration at the margins was much higher than that in the centre. These results indicate that Al distribution in the leaves is controlled by both rate and duration of transpiration. The mobility of Al between old and new leaves was studied by first growing plants in a solution with Al, followed by culture in a solution without Al. The Al content in the two new leaves appeared after removal of external Al was very low, whereas that in the old leaves did not decrease but continued to increase. The increased Al content was found to be translocated from Al remaining in the roots. It is concluded that Al is not mobile once it is accumulated in the leaf.
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Yu Z, Xu M, Santana-Rios G, Shen R, Izquierdo-Pulido M, Williams DE, Dashwood RH. A comparison of whole wheat, refined wheat and wheat bran as inhibitors of heterocyclic amines in the Salmonella mutagenicity assay and in the rat colonic aberrant crypt focus assay. Food Chem Toxicol 2001; 39:655-65. [PMID: 11397513 DOI: 10.1016/s0278-6915(01)00012-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Refined wheat, unrefined whole wheat, and wheat bran were studied for their ability to protect against heterocyclic amines (HCAs) in vitro and in vivo. Wheat bran, which binds HCAs in vitro, as well as refined wheat and unrefined whole wheat, inhibited the mutagenic activities of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) when they were co-incubated and the supernatant (minus grain) was added to the Salmonella assay. The water-soluble fraction alone from refined and unrefined wheat, but not bran, also inhibited against these mutagens in vitro. In vivo, AIN-93G diets containing refined wheat or unrefined wheat were examined for their ability to inhibit IQ-induced colonic aberrant crypt foci (ACF) in the Fischer 344 rat. A slight increase in the number of AC/ACF (aberrant crypts/ACF) was seen after 16 weeks in rats treated post-initiation with refined wheat (P < 0.05), and fewer foci with two or three aberrant crypts (ACF-2) were found in rats given unrefined whole wheat post-initiation compared with animals treated with the same diet during the initiation phase (P < 0.05). There was no significant difference in the profile of IQ urinary metabolites or excretion of promutagens 0-48 h after carcinogen dosing, and grains had no effect on hepatic cytochrome P4501A1 (CYP1A1), CYP1A2, aryl sulfotransferase or N-acetyltransferase activities; however, a slightly higher UDP-glucuronosyl transferase activity was observed in rats fed unrefined wheat compared with refined wheat diets (P < 0.05). Thus, despite their antimutagenic activities in vitro, only marginal effects were seen with refined and unrefined wheat in vivo with respect to hepatic enzyme activities, carcinogen metabolism and IQ-induced ACF in the rat colon.
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Singh AB, Norris K, Modi N, Sinha-Hikim I, Shen R, Davidson T, Bhasin S. Pharmacokinetics of a transdermal testosterone system in men with end stage renal disease receiving maintenance hemodialysis and healthy hypogonadal men. J Clin Endocrinol Metab 2001; 86:2437-45. [PMID: 11397836 DOI: 10.1210/jcem.86.6.7525] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Androgen deficiency is common in men with end stage renal disease (ESRD) on maintenance hemodialysis. Pharmacokinetics of transdermal testosterone in men receiving maintenance hemodialysis have not been studied. Our objective was to compare the pharmacokinetics of a transdermal testosterone system in healthy hypogonadal men and in men with ESRD on maintenance hemodialysis. We recruited 10 healthy hypogonadal men and 8 medically stable men on maintenance hemodialysis, 18--70 yr old, who had serum testosterone less than 300 ng/dL. After baseline sampling during a 24-h control period, two testosterone patches were applied daily for 28 days, to achieve a nominal delivery of 10-mg testosterone daily. In addition to single, pooled samples on days 7, 14, and 21, blood was drawn at 0, 2, 4, 6, 8, and 24 h on day 28 in healthy hypogonadal men and on an interdialytic day (day 21 or 28) as well as a dialysis day (day 21 or 28) in men on hemodialysis. On the dialysis day (day 21 or 28), serum free and total testosterone levels were measured hourly for 4 h before hemodialysis and for 4 h during hemodialysis. The dialysate was sampled for testosterone measurement. Baseline mean + SD total (92 +/- 82 vs. 222 +/- 50 ng/dL) and free (11 +/- 9 vs. 27 +/- 6 pg/mL) testosterone concentrations were lower in healthy hypogonadal men than in men with ESRD. After application of two testosterone patches, serum total and free testosterone concentrations rose into the midnormal range in both groups of men. Time-average, steady state (total testosterone, 506 +/- 88 vs. 516 +/- 86 ng/dL; free testosterone, 55 +/- 9 vs. 67 +/- 11 pg/mL), minimum, and maximum total and free testosterone concentrations were not significantly different between the two groups of men during treatment. Increments in total and free testosterone concentrations above baseline, baseline-subtracted areas under the total and free testosterone curves, and half-life of testosterone elimination (t(1/2), 2.1 +/- 0.1 vs. 2.1 +/- 0.2 h, P = not significant) were not significantly different between the two groups. In men receiving hemodialysis, time-average, steady state, and maximal total and free testosterone concentrations and baseline-subtracted areas under the total and free testosterone curves were higher on dialysis day than on an interdialytic day. On the day of hemodialysis, time-average total and free testosterone concentrations were not significantly different during the 4 h before or during hemodialysis. The amount of testosterone removed in the dialysate (8.4 +/- 1.6 microg during 4 h of hemodialysis) was small compared with the daily testosterone production rates in healthy young men. Serum dihydrotestosterone and estradiol concentrations increased into the normal male range and were not significantly different between the two groups. Percent suppression of LH was greater in men with ESRD than in healthy hypogonadal men. A regimen of two Testoderm TTS testosterone patches (Alza Corp., Mountain View, CA) daily can maintain serum concentrations of total and free testosterone and its metabolites dihydrotestosterone and estradiol in the midnormal range in healthy hypogonadal men and men on hemodialysis. The amount of testosterone cleared by hemodialysis is small, and hemodialysis does not significantly affect serum total and free testosterone concentrations in men treated with the testosterone patch.
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95
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Dai J, Shen R, Sumitomo M, Goldberg JS, Geng Y, Navarro D, Xu S, Koutcher JA, Garzotto M, Powell CT, Nanus DM. Tumor-suppressive effects of neutral endopeptidase in androgen-independent prostate cancer cells. Clin Cancer Res 2001; 7:1370-7. [PMID: 11350908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Expression of neutral endopeptidase (NEP) 24.11 is diminished in metastatic, androgen-independent prostate cancers (PCs; C. N. Papandreou et al., NAT: MED:, 4: 50--57, 1998). To determine the effects on androgen-independent PC cells of overexpressing cell-surface NEP, an inducible tetracycline-regulatory gene expression system was used to stably introduce and express the NEP gene in androgen-independent TSU-Pr1 cells generating WT-5 cells, which expressed high levels of enzymatically active NEP protein when cultured in the absence of tetracycline. TN12 cells, which contain the identical vectors without the NEP gene and do not express NEP, were used as control. Expression of NEP in WT-5 cells after removal of tetracycline from the media resulted in a >80% inhibition in cell proliferation over a 1-week period (P < 0.005) compared with control cells. Tumor formation occurred in the prostate glands of orthotopically injected athymic mice killed at 30 days in 4 of 5 mice that were given injections of 2 x 10(6) WT-5 cells and were fed doxycycline (NEP suppressed), and in all mice that were given injections of TN12 cells and were fed with or without doxycycline. In contrast, only 1 of 5 mouse prostates developed a tumor in mice that were given injections of WT-5 cells and that did not receive doxycycline. Analysis of the mechanisms of NEP-induced growth suppression revealed that NEP expression in WT-5 cells induced a 4-fold increase in the number of PC cells undergoing apoptosis, and increased the expression of p21 tumor suppressor gene protein and the level of unphosphorylated retinoblastoma protein as determined by Western blot. Flow cytometric analysis show that induced NEP expression in WT-5 cells resulted in a G(1) cell cycle arrest. These data show that NEP can inhibit PC cell growth and tumorigenicity and suggest that NEP has potential as therapy for androgen-independent PC.
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Sumitomo M, Milowsky MI, Shen R, Navarro D, Dai J, Asano T, Hayakawa M, Nanus DM. Neutral endopeptidase inhibits neuropeptide-mediated transactivation of the insulin-like growth factor receptor-Akt cell survival pathway. Cancer Res 2001; 61:3294-8. [PMID: 11309283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
G-protein coupled receptor (GPCR) agonists such as neuropeptides activate the insulin-like growth factor-1 receptor (IGF-IR) or the serine-threonine protein kinase Akt, suggesting that neuropeptides-GPCR signaling can cross-communicate with IGF-IR-Akt signaling pathways. Neutral endopeptidase 24.11 (NEP) is a cell-surface peptidase that cleaves and inactivates the neuropeptides endothelin-1 (ET-1) and bombesin, which are implicated in progression to androgen-independent prostate cancer (PC). We investigated the mechanisms of NEP regulation of neuropeptide-mediated cell survival in PC cells, including whether neuropeptide substrates of NEP induce phosphorylations of IGF-IR and Akt in PC cells. Western analyses revealed ET-1 and bombesin treatment induced phosphorylation of IGF-IRbeta and Akt independent of IGF-I in TSU-Pr1, DU145, and PC-3 PC cells, which lack NEP expression, but not in NEP-expressing LNCaP cells. Recombinant NEP and induced NEP expression in TSU-Pr1 cells using a tetracycline-repressive expression system inhibited ET-1-mediated phosphorylation of IGF-IRbeta and Akt, and blocked the protective effects of ET-1 against apoptosis induced by serum starvation. Incubation of TSU-Pr1 cells with specific kinase inhibitors together with ET-1 or bombesin showed that IGF-IR activation is required for neuropeptide-induced Akt phosphorylation, and that neuropeptide-induced Akt activation is predominantly mediated by Src and phosphatidylinositol 3-kinase but not by mitogen-activated protein kinase or protein kinase C. These data show that the neuropeptides ET-1 and bombesin stimulate ligand-independent activation of the IGF-IR, which results in Akt activation, and that this cross-communication between GPCR and IGF-IR signaling is inhibited by NEP.
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97
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Tavakkolizadeh A, Shen R, Jasleen J, Soybel DI, Jacobs DO, Zinner MJ, Ashley SW, Whang EE. Effect of growth hormone on intestinal Na+/glucose cotransporter activity. JPEN J Parenter Enteral Nutr 2001; 25:18-22. [PMID: 11190985 DOI: 10.1177/014860710102500118] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Growth hormone (GH) has been used alone or as part of a defined regimen in the treatment of patients with short bowel syndrome; however its mode of action remains unclear. Growth hormone has been shown to increase amino acid, water, and electrolyte absorption from the small intestine. The acute effect of growth hormone on intestinal sugar transport has not been described previously. METHODS Mucosal preparations of rat jejunum were mounted in the Ussing chamber. Growth hormone (2 x 10(-6) M or 8 x 10(-6) M) or vehicle was added to the serosal chamber 1, 3, or 5 hours later. Twenty or 40 minutes after growth hormone addition, 30 mmol/L 3-O-methylglucose was added to both chambers, and the change in short-circuit current (deltaIsc) was recorded. In separate experiments, tissues were pretreated with phloridzin, an inhibitor of Na+/glucose cotransport, before the addition of 3-O-methylglucose. In the final set of experiments, kinetic studies were performed. RESULTS GH did not induce any alterations in baseline electrical parameters. Only tissues left in the chambers for 5 hours, but not 1 or 3 hours, before GH treatment displayed a greater 3-O-methylglucose-induced deltaIsc than controls (p < .05). The increase in Isc induced by 3-O-methylglucose was 100% phloridzin-inhibitable. Kinetic analysis showed that growth hormone administration is associated with an increase in Na+/glucose cotransporter maximal velocity (Vmax) but no significant change in carrier affinity for substrate (Km). CONCLUSIONS Growth hormone increases intestinal sugar transport, but only in tissue that has not been exposed to endogenous GH for over 3 hours.
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Shen R, Sumitomo M, Dai J, Hardy DO, Navarro D, Usmani B, Papandreou CN, Hersh LB, Shipp MA, Freedman LP, Nanus DM. Identification and characterization of two androgen response regions in the human neutral endopeptidase gene. Mol Cell Endocrinol 2000; 170:131-42. [PMID: 11162897 DOI: 10.1016/s0303-7207(00)00326-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Transcription of the human neutral endopeptidase 24.11 (NEP) gene is androgen regulated in prostate cancer cells. Homology search identified a sequence GTCACAaagAGTTCT similar to the ARE consensus sequence GGTACAnnnTGTTCT within the 3'-untranslated region of the NEP mRNA. A double-stranded radiolabelled oligonucleotide containing this NEP-ARE sequence formed a DNA-protein complex with nuclear proteins from LNCaP cells or COS-7 cells co-transfected with an androgen receptor (AR) expression vector, and with full-length AR synthesized by baculovirus in mobility shift assays. Unlabeled NEP-ARE or consensus ARE but not mutated NEP-ARE replaced radiolabelled NEP-ARE. Steroid-dependent enhancement of transcription was assayed by transfecting ptkCAT reporter constructs containing the NEP-ARE into CV-1/AR cells and prostate cancer cells (PC-3/AR). Enhancement of chloramphenicol acetyltransferase (CAT) activity was increased four-fold by androgen, seven-fold by dexamethasone and three-fold by progesterone in CV-1/AR cells, and the NEP-ARE bound to glucocorticoid and progesterone receptor in mobility shift assays. We next performed DNase-I footprinting analysis of the NEP promoter and identified a 23 bp sequence GGTGCGGGTCGGAGGGATGCCCA (NEP-ARR) which was protected from DNase I cleavage by nuclear extracts from COS-7 cells expressing AR. This sequence was 62.5% homologous to an androgen responsive region (PSA-ARR) identified in the promoter of the prostate specific antigen (PSA) gene. A double-stranded radiolabelled oligonucleotide containing this NEP-ARR sequence formed DNA-protein complex with AR but not GR proteins. Unlabeled NEP-ARR, PSA-ARR and NEP-ARE replaced radiolabelled NEP-ARR. Steroid-dependent enhancement of transcription assays in PC-3/AR cells revealed that the enhancement of CAT activity was increased 2.3-fold by androgen, but not by glucocorticoid or progesterone. In a thymidine kinase promoter, the NEP-ARE and NEP-ARR together stimulated a five-fold increase in promoter activity in PC cells. These data suggest that steroid regulation of the NEP gene involves at least two elements including a typical ARE which binds androgen, progesterone and glucocorticoid receptors, and a unique ARR which only binds androgen receptor.
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Sumitomo M, Shen R, Walburg M, Dai J, Geng Y, Navarro D, Boileau G, Papandreou CN, Giancotti FG, Knudsen B, Nanus DM. Neutral endopeptidase inhibits prostate cancer cell migration by blocking focal adhesion kinase signaling. J Clin Invest 2000; 106:1399-407. [PMID: 11104793 PMCID: PMC381465 DOI: 10.1172/jci10536] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Neutral endopeptidase 24.11 (NEP, CD10) is a cell-surface enzyme expressed by prostatic epithelial cells that cleaves and inactivates neuropeptides implicated in the growth of androgen-independent prostate cancer (PC). NEP substrates such as bombesin and endothelin-1 induce cell migration. We investigated the mechanisms of NEP regulation of cell migration in PC cells, including regulation of phosphorylation on tyrosine of focal adhesion kinase (FAK). Western analyses and cell migration assays revealed an inverse correlation between NEP expression and the levels of FAK phosphorylation and cell migration in PC cell lines. Constitutively expressed NEP, recombinant NEP, and induced NEP expression using a tetracycline-repressive expression system inhibited bombesin- and endothelin-1-stimulated FAK phosphorylation and cell migration. This results from NEP-induced inhibition of neuropeptide-stimulated association of FAK with cSrc protein. Expression of a mutated catalytically inactive NEP protein also resulted in partial inhibition of FAK phosphorylation and cell migration. Coimmunoprecipitation experiments show that NEP associates with tyrosine-phosphorylated Lyn kinase, which then binds the p85 subunit of phosphatidylinositol 3-kinase (PI3-K) resulting in an NEP-Lyn-PI3-K protein complex. This complex competitively blocks FAK-PI3-K interaction, suggesting that NEP protein inhibits cell migration via a protein-protein interaction independent of its catalytic function. These experiments demonstrate that NEP can inhibit FAK phosphorylation on tyrosine and PC cell migration through multiple pathways and suggest that cell migration which contributes to invasion and metastases in PC cells can be regulated by NEP.
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Xu KF, Lu W, Li L, Shen R. Pulmonary complications in patients with AIDS: a report from a Beijing hospital. Respirology 2000; 5:419-21. [PMID: 11192557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
OBJECTIVE The aim of this study was to improve the awareness of pulmonary complications in patients with AIDS. METHODOLOGY Nine patients with AIDS with pulmonary involvement from March 1992 to March 2000 were analysed. RESULTS Of the nine cases, there were eight cases complicated with Pneumocystis carinii pneumonia (PCP). The clinical presentation of PCP was fever (8/8), dyspnoea on exertion or at rest (7/8), and hypoxaemia with a mean PaO2 of 58 mmHg. Chest X-ray films showed bilateral diffuse interstitial or alveolar infiltrates. Pulmonary tuberculosis, tuberculous lymphadenitis and bronchial fungal infection were found in three cases. CONCLUSIONS AIDS patients are at high risk of suffering from pulmonary complications, of which PCP is most common. If young patients who were healthy in the past suddenly suffered from pneumonia and respiratory failure, PCP should be considered. When opportunistic pulmonary infection is diagnosed under special circumstances, one should be alert to the possibility of AIDS and examine serum antihuman immunodeficiency virus (HIV) antibody.
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