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Amit DJ, Campbell C, Wong KYM. The interaction space of neural networks with sign-constrained synapses. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0305-4470/22/21/030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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252
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Brown RS, Campbell C, Lishman SC, Spittle MF, Miller RF. Plasmablastic lymphoma: a new subcategory of human immunodeficiency virus-related non-Hodgkin's lymphoma. Clin Oncol (R Coll Radiol) 1998; 10:327-9. [PMID: 9848336 DOI: 10.1016/s0936-6555(98)80089-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A patient with human immunodeficiency virus-related non-Hodgkin's lymphoma arising in the oral cavity is reported. The tumour had an unusual immunohistochemical profile that was negative for leucocyte common antigen and the B-cell antigen CD20 but positive for the plasma cell-reactive antibody VS38c. The features of this type of tumour, which has recently been categorized, are presented and discussed.
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MESH Headings
- Adult
- Diagnosis, Differential
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/classification
- Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Lymphoma, AIDS-Related/classification
- Lymphoma, AIDS-Related/diagnosis
- Lymphoma, AIDS-Related/pathology
- Male
- Mouth Neoplasms/classification
- Mouth Neoplasms/diagnosis
- Mouth Neoplasms/pathology
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Finch H, Pegg NA, McLaren J, Lowdon A, Bolton R, Coote SJ, Dyer U, Montana JG, Owen MR, Dowle M, Buckley D, Ross BC, Campbell C, Dix C, Mooney C, Man-Tang C, Patel C. 5,5-trans lactone-containing inhibitors of serine proteases: identification of a novel, acylating thrombin inhibitor. Bioorg Med Chem Lett 1998; 8:2955-60. [PMID: 9873654 DOI: 10.1016/s0960-894x(98)00531-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Synthesis of a variety of 5,5-trans fused lactones, related to compounds found in extracts of Lantana camara, has provided a series of novel acylating inhibitors of human thrombin, trypsin, chymotrypsin and human leucocyte elastase. The most effective thrombin inhibitor is 7 with an IC50 of 130 nM and a Kobs/[1] of 4,000 M-1 s-1.
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Gelmon KA, Tolcher A, O'Reilly S, Campbell C, Bryce C, Shenkier T, Ragaz J, Ayers D, Nakashima L, Rielly S, Dulude H. A phase I-II study of bi-weekly paclitaxel as first-line treatment in metastatic breast cancer. Ann Oncol 1998; 9:1247-9. [PMID: 9862057 DOI: 10.1023/a:1008445123416] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Single-agent bi-weekly paclitaxel was studied as first-line metastatic treatment for breast cancer in a phase I-II trial. PATIENTS AND METHODS Thirty-eight women with metastatic breast cancer were enrolled. Thirty-seven are evaluable for toxicity, 35 for response. RESULTS The MTD was defined at 160 mg/m2 q two weeks with dose limiting toxicity in two patients consisting of hematological toxicity (1) and neurotoxicity (2). Twenty patients were treated at 150 mg/m2, the recommended dose. Response rates were two CRs and nine PRs (overall 61%) at the RD of 150 mg/m2 and three CRs and 11 PRs for an overall RR of 67% for the two top doses. CONCLUSIONS The good drug tolerance, response rates, and convenience over weekly treatment suggest this may be a worthwhile regimen.
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Williams B, Campbell C. Creating alliances for disease management in industrial settings: a case study of HIV/AIDS in workers in South African gold mines. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 1998; 4:257-64. [PMID: 9876635 DOI: 10.1179/oeh.1998.4.4.257] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The epidemic of HIV/AIDS is at an advanced stage in many African countries, but little attention has been given to the impact that this will have in industrial settings. Using the Southern African mining industry as a case study, the authors consider the state of the HIV epidemic and discuss programs that have been undertaken to manage HIV. They critically analyze the reasons current interventions have had little impact on HIV among mine workers, tracing the lack of success to neglect of the social and community contexts within which HIV transmission takes place, as well as the lack of attention to the psychosocial processes and mechanisms underlying disease transmission. Finally, they present an intervention that aims to address the limitations of existing industrial programs and improve the management of sexually transmitted diseases (STDs), including HIV, in a particular occupational setting through creating alliances between a wide range of community stakeholders. The intervention aims not only to reduce STDs, promote awareness of HIV risks, and distribute condoms, as existing programs have done, but also to address the broader social, cultural, and community contexts that facilitate HIV transmission.
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257
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Roscoe DE, Holste WC, Sorhage FE, Campbell C, Niezgoda M, Buchannan R, Diehl D, Niu HS, Rupprecht CE. Efficacy of an oral vaccinia-rabies glycoprotein recombinant vaccine in controlling epidemic raccoon rabies in New Jersey. J Wildl Dis 1998; 34:752-63. [PMID: 9813845 DOI: 10.7589/0090-3558-34.4.752] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A field trial to evaluate the efficacy of an oral vaccinia-rabies glycoprotein recombinant virus vaccine in controlling epidemic raccoon (Procyon lotor) rabies was conducted by distributing 180,816 doses (10(8.2)TCID50/ml) of vaccine in wax ampules within fish-meal polymer baits at a rate of 64 doses/km2/treatment throughout a 552 km2 area, forming an 18 km wide band across the northern Cape May Peninsula of New Jersey (USA). Vaccination treatments were conducted in the spring and fall between May 1992 and October 1994 from a helicopter along ecotones and from motor vehicles along roads. Vaccine-laden baits were removed by animals from tracking stations within 3 wk and 61% of the identifiable tracks were those of raccoons. Tetracycline incorporated in the baits as a biomarker was detected in 155 (73%) of the vaccination area raccoons following the fall 1993 and spring 1994 vaccinations. Eleven (61%) of the raccoons sampled in the same time period seroconverted (> or = 0.5 IU) in response to rabies virus glycoprotein. A raccoon diagnosed with rabies from the northern border of the vaccination area on 30 April 1993 provided the first evidence that the barrier was being challenged by the rabies epidemic. The prevalence of rabies in raccoons from the vaccination area for the first year (10%, n = 96) and second year (8%, n = 61) of challenge was reduced more than six-fold by vaccination compared to unvaccinated raccoons from northern adjacent surveillance areas during the corresponding first (65%, n = 189) and second years (53%, n = 43). Vaccination also effectively reduced by three-fold the rate at which the epidemic moved through the raccoon population (15 km/yr). The breach of the vaccination area resulted in a resumption of the high rate (43 km/yr) of epidemic movement and a significant nine-fold increase in rabies prevalence (77%, n = 47). The maximum linear movement (12.9 km) among five ear-tagged rabid raccoons in the study area was significantly greater than that of 19 normal radio-collared raccoons (2.58 km) in the area. These large movements of rabid raccoons, together with relocation of nuisance raccoons, spillover of raccoon rabies in skunks (Mephitis mephitis) and other species, insufficient funding and a decision to discontinue the program in 1994 (which could have resulted in insufficient population immunity among raccoons in the vaccination area) may have contributed to the eventual breach of the barrier.
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Campbell C. A commission for the 21st century. THE MODERN LAW REVIEW 1998; 61:598-602. [PMID: 12656079 DOI: 10.1111/1468-2230.00169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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259
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Thyagarajan B, Lundberg R, Rafferty M, Campbell C. Nucleolin promotes homologous DNA pairing in vitro. SOMATIC CELL AND MOLECULAR GENETICS 1998; 24:263-72. [PMID: 10696234 DOI: 10.1023/b:scam.0000007129.98789.1f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We purified to near homogeneity a previously identified 100 kDa mammalian homologous DNA pairing protein. The purified 100 kDa protein also catalyzed high levels of cell-free homologous DNA recombination activity. This ATP-dependent activity was capable of forming conservative recombinant products between two circular, double-stranded DNA molecules. We were unable to detect any DNA polymerase, DNA ligase, or 5' or 3' exonuclease activity associated with this purified material. The purified 100 kDa protein bound silver nitrate as well as a monoclonal antibody specific for nucleolin. A recombinant protein comprised of the Escherichia coli maltos-ebinding protein fused to the carboxyl-terminal two-thirds of human nucleolin possessed homologous DNA pairing activity. These data indicate that the 100 kDa homologous DNA pairing protein is nucleolin. The observation that nucleolin can carry out homologous DNA strand pairing in vitro raises the prospect that it may function similarly in vivo.
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260
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Montpetit ML, Ratnam S, Campbell C, Gleeson T, Donovan C, Tollefson J. Molecular epidemiological analysis of human immunodeficiency virus type 1 in Newfoundland, Canada. AIDS Res Hum Retroviruses 1998; 14:1205-9. [PMID: 9737592 DOI: 10.1089/aid.1998.14.1205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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261
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Abstract
Namibia is a sparsely populated nation in southwest Africa. A state-run health service provides care to most of the population. The geography and population distribution dictate the delivery systems for prehospital and emergency care. A state-run ambulance service provides basic patient transportation to the state-run hospitals. There is no 911 system. Two private aeromedical companies in Namibia provide the full range of ground and aeromedical treatment, diver rescue, and helicopter and fixed-wing transport services. The scope of care includes cricothyrotomies, chest tubes, and rapid-sequence intubation. Equipment is modern and virtually identical to what is used in the United States. There are no emergency physicians in Namibia. General medical officers are the backbone of the state-run health service. General medical officers assigned to cover the ED are called casualty officers. No specialized training beyond internship is required, and assignments to casualty are viewed as temporary until better positions become available. Only the largest state hospital in the capital has a dedicated, 24-hour emergency staff. The private prehospital care/transport systems are well organized and sophisticated. Formal efforts should be undertaken to develop ties with our colleagues in Namibia. Potential areas for collaboration include injury surveillance and prevention, field trauma resuscitation, and prehospital care.
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262
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Campbell C. Optical isolation of portions of a wave front. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 1998; 15:2530-2535. [PMID: 9729865 DOI: 10.1364/josaa.15.002530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A criterion is established for determining when portions of a wave front can be said to be optically isolated from the rest of the wave front in the sense that they can subsequently be treated separately when one is considering the formation of images. The subarea of the wave front is treated as a separate aperture, and it is said to be isolated if diffraction maxima for the majority of the wave front fall at or beyond the first minima for the subarea. An illustrative example employing two circular unequal-diameter apertures is presented. A method is given for identifying portions of wave front that may be optically isolated; the method uses the technique of fitting a reference surface to the actual wave front and then finding what is defined as the differential deflection of the actual surface with respect to the reference surface at all locations. Subpopulations of locations with similar differential deflection values, sufficient numbers, and sufficient differential deflection are candidates for area of optical isolation.
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Rancatore E, Dandapani BK, Campbell C, Sahasranaman V, Parks P. Emergent stroke awareness among the elderly. J Stroke Cerebrovasc Dis 1998. [DOI: 10.1016/s1052-3057(98)80074-8] [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] Open
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264
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Aziz T, el-Gamel A, Krysiak P, Rahman A, Campbell C, Yonan N, Deiraniya A. Ten year experience in orthotopic heart transplantation: single center result. Transplant Proc 1998; 30:1915-6. [PMID: 9723331 DOI: 10.1016/s0041-1345(98)00480-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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265
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Aziz TM, Sheldon S, el-Gamel A, Krysiak P, Campbell C, Rahman A, Dyer P, Yonan N, Deiraniya A. Implication of HLA mismatch in the clinical outcome of orthotopic heart transplantation. Transplant Proc 1998; 30:1917-9. [PMID: 9723332 DOI: 10.1016/s0041-1345(98)00481-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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266
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el Gamel A, Grant S, Yonan N, Keevil B, Aziz T, Deiraniya AK, Campbell C, Rahman A, Haselton P, Hutchinson IV. Interleukin-10 and cellular rejection following cardiac transplantation. Transplant Proc 1998; 30:2387-8. [PMID: 9723513 DOI: 10.1016/s0041-1345(98)00663-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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267
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Aziz TM, Krysiak P, el-Gamel A, Campbell C, Rahman A, Deiraniya A, Isalska B, Yonan N. Bacteremia and endocarditis following endomyocardial biopsy. Transplant Proc 1998; 30:2112-3. [PMID: 9723409 DOI: 10.1016/s0041-1345(98)00556-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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268
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Aziz T, el-Gamel A, Krysiak P, Rahman A, Campbell C, Yonan N, Deiraniya A. Risk factors for early mortality, acute rejection, and factors affecting first-year survival after heart transplantation. Transplant Proc 1998; 30:1912-4. [PMID: 9723330 DOI: 10.1016/s0041-1345(98)00479-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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269
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Aziz T, el-Gamel A, Keevil B, Krysiak P, Campbell C, Rahman A, Deiraniya A, Yonan N. Clinical impact of Neoral in thoracic organ transplantation. Transplant Proc 1998; 30:1900-3. [PMID: 9723326 DOI: 10.1016/s0041-1345(98)00475-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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270
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Downing RG, Otten RA, Marum E, Biryahwaho B, Alwano-Edyegu MG, Sempala SD, Fridlund CA, Dondero TJ, Campbell C, Rayfield MA. Optimizing the delivery of HIV counseling and testing services: the Uganda experience using rapid HIV antibody test algorithms. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1998; 18:384-8. [PMID: 9704945 DOI: 10.1097/00042560-199808010-00011] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The AIDS Information Center (AIC) was established in Kampala, Uganda in 1990 in response to increasing interest by members of the general public who wished to know their HIV serostatus. By 1996, >300,000 clients had been seen. HIV serologic testing was performed at a central laboratory and results reported back to AIC after 2 weeks. Approximately 25% of clients failed to learn their HIV serostatus as a result of failure to return or late arrival of results. To address these issues, AIC carried out an evaluation of 3 rapid HIV assays, Sero-Strip, SeroCard, and Capillus, against a standard criterion to identify a testing algorithm that could be used as an on-site confirmatory testing strategy. The study was carried out over a period of 5 working days and 325 clients were seen. An algorithm was identified, which gave no indeterminate results with unambiguously positive or negative specimens, which was 100% sensitive and specific, and which could be integrated with minimal disruption into existing counseling procedures. All clients left AIC knowing their HIV serostatus and having spent <2 hours at the Center. The results of this evaluation demonstrate that "same-day" results can be provided in counseling and testing settings without compromising the quality of counseling or the accuracy of HIV testing.
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271
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Campbell C, Romero DP. Identification and characterization of the RAD51 gene from the ciliate Tetrahymena thermophila. Nucleic Acids Res 1998; 26:3165-72. [PMID: 9628914 PMCID: PMC147671 DOI: 10.1093/nar/26.13.3165] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The RAD51 gene is a eukaryotic homolog of rec A, a critical component in homologous recombination and DNA repair pathways in Escherichia coli . We have cloned the RAD51 homolog from Tetrahymena thermophila , a ciliated protozoan. Tetrahymena thermophila RAD51 encodes a 36.3 kDa protein whose amino acid sequence is highly similar to representative Rad51 homologs from other eukaryotic taxa. Recombinant Rad51 protein was purified to near homogeneity following overproduction in a bacterial expression system. The purified protein binds to both single- and double-stranded DNA, possesses a DNA-dependent ATPase activity and promotes intermolecular ligation of linearized plasmid DNA. While steady-state levels of Rad51 mRNA are low in normally growing cells, treatment with UV light resulted in a >100-fold increase in mRNA levels. This increase in mRNA was time dependent, but relatively independent of UV dose over a range of 1400-5200 J/m2. Western blot analysis confirmed that Rad51 protein levels increase upon UV irradiation. Exposure to the alkylating agent methyl methane sulfonate also resulted in substantially elevated Rad51 protein levels in treated cells, with pronounced localization in the macronucleus. These data are consistent with the hypothesis that ciliates such as T.thermophila utilize a Rad51-dependent pathway to repair damaged DNA.
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272
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Aziz T, el-Gamel A, Keevil B, Martyszczuk R, Campbell C, Rahman A, Deiraniya A, Yonan N. Clinical impact of Neoral in heart transplantation. Transplant Proc 1998; 30:1152-3. [PMID: 9636466 DOI: 10.1016/s0041-1345(98)00188-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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273
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Schwachtgen JL, Houston P, Campbell C, Sukhatme V, Braddock M. Fluid shear stress activation of egr-1 transcription in cultured human endothelial and epithelial cells is mediated via the extracellular signal-related kinase 1/2 mitogen-activated protein kinase pathway. J Clin Invest 1998; 101:2540-9. [PMID: 9616225 PMCID: PMC508843 DOI: 10.1172/jci1404] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The primary response transcription factor, early growth response-1 (Egr-1), is rapidly activated by a variety of extracellular stimuli. Egr-1 binds to a sequence found in the promoters of genes involved in vascular injury, such as PDGF-A and tissue factor, and trans-activates their expression in endothelial cells in response to fluid shear stress. Here we show that egr-1 mRNA is increased after 30 min of flow in human aortic endothelial cell and HeLa cell cultures. Transient transfection of HeLa cells with reporter gene constructs driven by the murine or human egr-1 5' flanking sequence revealed a five- and ninefold induction, respectively, in transcriptional activity after exposure to a shear stress of 5 dynes/cm2 for 3 h. Deletion of sequences in the murine promoter containing two AP1 sites and an inhibitory Egr-1 binding sequence, did not reduce shear stress inducibility. However, progressive deletion of five serum response elements, reduced both the basal promoter activity and its capacity to be activated by shear stress. Further examination indicated that the three upstream serum response elements are predominantly responsible for shear stress activation of the egr-1 promoter. Treatment of cells with PD98059, a specific inhibitor of mitogen-activated protein kinase-1 inhibited shear stress activation of egr-1. We suggest that egr-1 activation by shear stress involves activation of Elk-1 but not c-jun activity. These data, which are consistent with previous findings for shear mediated signaling via the mitogen-activated protein kinase cascade, now implicate shear modulation of the Egr-1 transcription factor in this pathway.
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274
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el-Gamel A, Awad M, Yonan N, Keevil B, Egan J, Campbell C, Rahman AN, Haselton P, Deiraniya AK, Hutchinson IV. Does cyclosporin promote the secretion of transforming growth factor-beta 1 following pulmonary transplantation? Transplant Proc 1998; 30:1525-7. [PMID: 9636621 DOI: 10.1016/s0041-1345(98)00344-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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275
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Rieley G, Teece MA, Peakman TM, Raven AM, Greene KJ, Clarke TP, Murray M, Leftley JW, Campbell C, Harris RP, Parkes RJ, Maxwell JR, Campbell CN. Long-chain alkenes of the haptophytes Isochrysis galbana and Emiliania huxleyi. Lipids 1998; 33:617-25. [PMID: 9655378 DOI: 10.1007/s11745-998-0248-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The major alkenes of the haptophytes Isochrysis galbana (strain CCAP 927/14) and Emiliania huxleyi (strains CCAP 920/2 and VAN 556) have been identified by nuclear magnetic resonance spectroscopy and by mass spectrometric analysis of their dimethyl disulfide adducts. The dominant alkene in I. galbana is (22Z)-1 ,22-hentriacontadiene, with 1,24-hentriacontadiene and 1,24-tritriacontadiene present in much lower abundance; (22Z)-1,22-hentriacontadiene also occurs in E. huxleyi (strain CCAP 920/2), together with (2Z,22Z)-2,22-hentriacontadliene (the major hydrocarbon) and (3Z,22Z)-3,22-hentriacontadiene. Minor abundances of 2,24-hentriacontadiene and 2,24-tritriacontadiene are also present in this strain. In contrast, the dominant alkene in E. huxleyi (strain VAN 556) is (15 E,22E)-1,16,23-heptatriacontatriene with the related alkatriene 1,15,22-octatriacontatriene also present and (22Z)-1,22-hentriacontadiene occurring as a minor component. From structural relationships (15E,22E)-1,15,22-heptatriacontatriene is proposed to derive from the same biosynthetic pathway as that of the characteristic C37 alkenones which occur in both E. huxleyi and I. galbana. The C31 and C33 dienes likely derive from chain extension and decarboxylation of (Z)-9-octadecenoic acid or (Z)-7-hexadecenoic acid, using a pathway analogous to that elucidated previously in the chlorophyte Botryococcus braunii. Therefore, long-chain dienes and trienes, which can co-occur in haptophytes, may have distinct biosynthetic pathways.
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