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Peters R, Demerais L. Improving mental health services for urban First Nations: policy issues relevant to health care reform. Can J Commun Ment Health 1998; 16:29-36. [PMID: 10181475 DOI: 10.7870/cjcmh-1997-0004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This paper discusses issues related to the development of plans to improve the effectiveness of mental health services for urban First Nations people. The discussion focuses on emerging issues related to health care reform and regionalization. While it is impossible to make specific recommendations without reference to local conditions, developing an awareness of the general issues involved will help in the process of identifying the principles and approaches needed to frame local solutions.
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Affiliation(s)
- R Peters
- Tsimshian Nation, Greater Vancouver Mental Health Service
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202
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Peters R, Sikorski R. Mass-spectroscopic genomics. Science 1998; 279:1230. [PMID: 9508693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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203
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Peters R, Sikorski R. Molecular plumbing. Science 1998; 279:1230-1. [PMID: 9508694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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204
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Affiliation(s)
- R Peters
- Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
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Benhattar J, Perey L, Peters R, Leyvraz S. Reverse transcriptase-polymerase chain reaction and islet cell carcinoma: not antagonist, but complementary tools. J Clin Oncol 1998; 16:806-7. [PMID: 9469379 DOI: 10.1200/jco.1998.16.2.806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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206
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Di Mario C, Görge G, Peters R, Kearney P, Pinto F, Hausmann D, von Birgelen C, Colombo A, Mudra H, Roelandt J, Erbel R. Clinical application and image interpretation in intracoronary ultrasound. Study Group on Intracoronary Imaging of the Working Group of Coronary Circulation and of the Subgroup on Intravascular Ultrasound of the Working Group of Echocardiography of the European Society of Cardiology. Eur Heart J 1998; 19:207-29. [PMID: 9519314 DOI: 10.1053/euhj.1996.0433] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- C Di Mario
- Cardiac Catheterization Laboratory, Centro Cuore Columbus, Milano, Italy
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207
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Kochak GM, Page JG, Buchanan RA, Peters R, Padgett CS. Steady-state pharmacokinetics of zonisamide, an antiepileptic agent for treatment of refractory complex partial seizures. J Clin Pharmacol 1998; 38:166-71. [PMID: 9549648 DOI: 10.1002/j.1552-4604.1998.tb04406.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A 56-day pharmacokinetic study of zonisamide was conducted in 24 healthy volunteers. Steady state was achieved in 29 days including two dose escalations, and in an average of 15 days from the last dose adjustment. Twice-daily administration of 200 mg every 12 hours produced a 14% serum level fluctuation at steady state. After once-daily administration of 400 mg, a 27% serum level fluctuation was observed. The terminal-phase half-life after the last dose was 63 to 69 hours, which is consistent with the half-life of 52 to 60 hours found in single-dose studies. This result demonstrates that zonisamide is not an autoinducer. Serum oral clearance of 0.60 to 0.71 L/hr (0.121-0.132 mL/min/kg) was similar to that observed in other multiple-dose studies.
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Affiliation(s)
- G M Kochak
- Kansas City Analytical Services, Shawnee, Kansas 66216, USA
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208
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Sikorski R, Peters R. Droplet discovery. Science 1998; 279:412-3. [PMID: 9454334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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209
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Sikorski R, Peters R. Lactamase live! Science 1998; 279:412. [PMID: 9454333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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210
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Grote M, Peters R. Mapping proteins to nuclear pore complexes by immunogold electron microscopy. Methods Cell Biol 1997; 53:287-302. [PMID: 9348513 DOI: 10.1016/s0091-679x(08)60883-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- M Grote
- Institut für Medizinische Physik und Biophysik, Westfälische Wilhelms-Universität, Münster, Germany
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211
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Kubitscheck U, Peters R. Localization of single nuclear pore complexes by confocal laser scanning microscopy and analysis of their distribution. Methods Cell Biol 1997; 53:79-98. [PMID: 9348505 DOI: 10.1016/s0091-679x(08)60875-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- U Kubitscheck
- Institut für Medizinische Physik und Biophysik, Westfälische Wilhelms-Universität, Münster, Germany
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212
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Sikorski R, Peters R. Cell shocked. Science 1997; 278:2143, 2145. [PMID: 9432724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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213
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Sikorski R, Peters R. Capturing genes. Science 1997; 278:2143. [PMID: 9432723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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214
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Sikorski R, Peters R. Allergy and immunology on the Internet. JAMA 1997; 278:2029-30. [PMID: 9396667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R Sikorski
- National Cancer Institute, Bethesda, Md, USA.
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215
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van der Klooster JM, Peters R, Ashruf RZ, Grootendorst AF. Hyponatraemia and the syndrome of inappropriate antidiuretic hormone secretion with convulsions, coma and pulmonary oedema in a patient using paroxetine. Neth J Med 1997; 51:237-9. [PMID: 9499696 DOI: 10.1016/s0300-2977(97)00075-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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216
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Düsterwald HG, Höhlein B, Kraut H, Meusinger J, Peters R, Stimming U. Methanol steam-reforming in a catalytic fixed bed reactor. Chem Eng Technol 1997. [DOI: 10.1002/ceat.270200908] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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217
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Braun HA, Schäfer K, Voigt K, Peters R, Bretschneider F, Pei X, Wilkens L, Moss F. Low-dimensional dynamics in sensory biology. 1: Thermally sensitive electroreceptors of the catfish. J Comput Neurosci 1997; 4:335-47. [PMID: 9427119 DOI: 10.1023/a:1008852000496] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We report the results of a search for evidence of periodic unstable orbits in the electroreceptors of the catfish. The function of these receptor organs is to sense weak external electric fields. In addition, they respond to the ambient temperature and to the ionic composition of the water. These quantities are encoded by receptors that make use of an internal oscillator operating at the level of the membrane potential. If such oscillators have three or more degrees of freedom, and at least one of which also exhibits a nonlinearity, they are potentially capable of chaotic dynamics. By detecting the existence of stable and unstable periodic orbits, we demonstrate bifurcations between noisy stable and chaotic behavior using the ambient temperature as a parameter. We suggest that the technique developed herein be regarded as an additional tool for the analysis of data in sensory biology and thus can be potentially useful in studies of functional responses to external stimuli. We speculate that the appearance of unstable orbits may be indicative of a state of heightened sensory awareness by the animal.
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Affiliation(s)
- H A Braun
- Department of Physiology, University of Marburg, Germany
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218
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Peters R, Sikorski R. Vintage care. Geriatrics resources on the Net. JAMA 1997; 278:1299-300. [PMID: 9343442 DOI: 10.1001/jama.278.16.1299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R Peters
- Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
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Affiliation(s)
- R Sikorski
- National Cancer Institute, Bethesda, Maryland, USA
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222
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Levendag PC, Peters R, Meeuwis CA, Visch LL, Sipkema D, de Pan C, Schmitz PI. A new applicator design for endocavitary brachytherapy of cancer in the nasopharynx. Radiother Oncol 1997; 45:95-8. [PMID: 9364638 DOI: 10.1016/s0167-8140(97)00105-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
INTRODUCTION In attempting to improve local tumor control by higher doses of radiation, there has been a resurgence of interest in the implementation of brachytherapy in the management of primary and recurrent cancers of the nasopharynx. Brachytherapy with its steep dose fall-off is of particular interest because of the proximity of critical dose limiting structures. Recent developments in brachytherapy, such as the introduction of pulsed-dose-rate and high-dose-rate computerized afterloaders, have encouraged further evolution of brachytherapy techniques. MATERIALS AND METHODS We have designed an inexpensive, re-usable and flexible silicone applicator, tailored to the shape of the soft tissues of the nasopharynx, which can be used with either low-dose-rate brachytherapy or high (pulsed)-dose-rate remote controlled afterloaders. RESULTS AND CONCLUSIONS This Rotterdam nasopharynx applicator proved to be easy to introduce, patient friendly and can remain in situ for the duration of the treatment (2-6 days). The design, technique of application and the first consecutive 5 years of clinical experience in using this applicator are presented.
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Affiliation(s)
- P C Levendag
- Department of Radiation Oncology, Daniel den Hoed Cancer Center/Dijkzigt Hospital, University Hospital Rotterdam, The Netherlands
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223
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Peters R, Sikorski R. Just one word: plastics. Science 1997; 277:1849. [PMID: 9324772 DOI: 10.1126/science.277.5333.1849a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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224
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225
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Sikorski R, Peters R. The ED and the PC. Internet resources for emergency and disaster care. JAMA 1997; 278:869-70. [PMID: 9293999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R Sikorski
- National Cancer Institute, Bethesda, Md, USA.
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226
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Sikorski R, Peters R. Laser-controlled cells. Science 1997; 277:975. [PMID: 9281075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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227
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Sikorski R, Peters R. Selecting the needle. Science 1997; 277:975. [PMID: 9281076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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228
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Affiliation(s)
- R Peters
- Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
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229
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Sikorski R, Peters R. Xenotransplanters turn xenovirologists. Science 1997; 276:1893. [PMID: 9206845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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230
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Peters R, Sikorski R. How to use Usenet. Science 1997; 276:1893, 1894. [PMID: 9206846 DOI: 10.1126/science.276.5320.1893b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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231
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Sikorski R, Peters R. A cell growth switch. Science 1997; 276:1891. [PMID: 9206844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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232
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Affiliation(s)
- R Sikorski
- National Cancer Institute, Bethesda, Md, 20892, USA
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233
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Sikorski R, Peters R. World Wide Web sites in biotechnology. Nat Biotechnol 1997; 15:475. [PMID: 9131630 DOI: 10.1038/nbt0597-475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- R Sikorski
- Department of Medicine, Massachusetts General Hospital, USA.
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Affiliation(s)
- R Peters
- Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
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235
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Middeler G, Zerf K, Jenovai S, Thulig A, Tschödrich-Rotter M, Kubitscheck U, Peters R. The tumor suppressor p53 is subject to both nuclear import and export, and both are fast, energy-dependent and lectin-inhibited. Oncogene 1997; 14:1407-17. [PMID: 9136984 DOI: 10.1038/sj.onc.1200949] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Human p53 was expressed in E. coli, purified, labeled with fluorescein iodoacetamide (IAF) and characterized for sequence-specific DNA binding and epitope disposition. Injected into the cytoplasm or nuclei of 3T3 cells IAF-p53 was imported into or exported from nuclei within minutes. Import was inhibited by coinjection of the lectin wheat germ agglutinine (WGA). In contrast, the peptide-protein conjugate NLS-HSA carrying the nuclear localization sequence (NLS) of the SV40 T antigen was only imported but not exported. 3T3 polykaryons were injected with IAF-p53 and photo-bleached by Scanning Microphotolysis in such a manner that only a single nucleus per polykaryon remained non-bleached. IAF-p53 was found to migrate rapidly (halftime 10 min) from non-bleached into bleached nuclei, while NLS-HSA did not. In digitonin permeabilized cells IAF-p53 was imported into nuclei. When removed from the medium after nuclear accumulation IAF-p53 was exported from the nuclei. Nuclear import and export of IAF-p53 both were rapid (halftimes of a few minutes, 22 C) and strongly inhibited by WGA or incubation on ice. NLS-HSA was only imported but not exported. We conclude that the nucleocytoplasmic transport of p53, in contrast to that of NLS-HSA, is bidirectional and that transport in both directions is carrier mediated and energy dependent. These results suggest that p53 contains nuclear export signals (NES) in addition to import signals (NLS) and thus open new views on the potential regulation of p53 cellular fractions.
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Affiliation(s)
- G Middeler
- Institut für Medizinische Physik und Biophysik, Westfälische Wilhelms-Universität, Münster, Germany
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236
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Sikorski R, Peters R. Medical literature made easy. Querying databases on the Internet. JAMA 1997; 277:959-60. [PMID: 9091660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- R Sikorski
- National Cancer Institute, Bethesda, Md. 20892, USA
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Affiliation(s)
- R Peters
- Department of Medicine Massachusetts General Hospital, USA.
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239
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Affiliation(s)
- R Sikorski
- National Cancer Institute, Bethesda, Md, USA.
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Peters R, Sikorski RS. Protein databases on the WWW. Nat Biotechnol 1997; 15:90. [PMID: 9035114 DOI: 10.1038/nbt0197-90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- R Peters
- Department of medicine, Masachusetts General Hospital.
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241
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Hausser H, Wedekind P, Sperber T, Peters R, Hasilik A, Kresse H. Isolation and cellular localization of the decorin endocytosis receptor. Eur J Cell Biol 1996; 71:325-31. [PMID: 8980902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The small dermatan sulfate proteoglycans decorin and biglycan are efficiently internalized by a variety of cells of mesenchymal origin. This process is modulated, at least under tissue culture conditions, by cell surface-associated heparan sulfate proteoglycans. Receptor proteins of 51 and 26 kDa, respectively, bind to leucine-rich repeat structures of the core proteins of the small proteoglycans but also to highly sulfated domains of heparan sulfate. The 51 kDa protein was purified from rat brain tissue by subcellular fractionation, heparin affinity chromatography and subsequent SDS-PAGE, and was used for raising a polyclonal antiserum. Affinity-purified antibodies also recognize the 26 kDa protein and a few other low molecular weight proteins, suggesting that these proteins represent proteolytic degradation products of the 51 kDa receptor. By confocal laser microscopy, it could be demonstrated that the affinity-purified antibody reacted at 0 degree C with a protein that became internalized and was transported to a perinuclear compartment during 15 min of incubation at 37 degrees C. These findings provide direct evidence that the receptor protein(s) are internalized together with the ligand and reach an endosomal compartment where further sorting can occur.
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Affiliation(s)
- H Hausser
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Germany
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242
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Affiliation(s)
- R Peters
- National Coalition for Gun Control, Camperdown, NSW, Australia
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243
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Berkowitz K, Peters R, Kjos SL, Goico J, Marroquin A, Dunn ME, Xiang A, Azen S, Buchanan TA. Effect of troglitazone on insulin sensitivity and pancreatic beta-cell function in women at high risk for NIDDM. Diabetes 1996; 45:1572-9. [PMID: 8866563 DOI: 10.2337/diab.45.11.1572] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We conducted a randomized placebo-controlled study to determine the effects of the thiazolidinedione compound troglitazone on whole-body insulin sensitivity (SI), pancreatic beta-cell function, and glucose tolerance in 42 Latino women with impaired glucose tolerance (IGT) and a history of gestational diabetes mellitus (GDM), characteristics that carry an 80% risk of developing NIDDM within 5 years. After baseline oral (OGTT) and intravenous (IVGTT) glucose tolerance testing, subjects were assigned to take placebo or 200 or 400 mg troglitazone daily for 12 weeks (14 subjects per treatment group). An OGTT and IVGTT were repeated during the 12th week of treatment. Five subjects failed to complete the trial for personal reasons, and medication compliance averaged 90% in the remaining subjects, none of whom experienced a serious adverse event. SI, calculated by minimal model analysis of IVGTT results, changed by only 4 +/- 14% during 12 weeks of placebo administration, but increased 40 +/- 22 and 88 +/- 22% above basal during treatment with 200 and 400 mg troglitazone, respectively (P = 0.01 among groups). Troglitazone administration was also associated with a dose-dependent reduction in the total insulin area during IVGTTs, which was highly significant (P < 0.001), and with a reduction during OGTTs, which approached statistical significance (P = 0.09). Glucose tolerance improved slightly in all groups, but the magnitude of change did not differ significantly among groups, whether it was assessed as the number of subjects who continued to manifest IGT at 12 weeks (P = 0.64 among groups), the change in total glucose area during OGTTs (P = 0.58), or the change in fractional glucose disappearance rates during IVGTTs (P = 0.28). Among the women who received troglitazone, the greatest improvement in SI occurred in the women who had the highest diastolic blood pressures and the best IVGTT insulin responses during baseline testing. Our findings indicate that troglitazone improved whole-body insulin sensitivity and lowered circulating insulin concentrations in women with prior GDM who are at very high risk for NIDDM. The lack of improvement in glucose tolerance despite improved insulin sensitivity may be a manifestation of the beta-cell defect that predisposes the women to NIDDM. The overall pattern of response to troglitazone in our high-risk patients indicates that the drug is an ideal agent with which to test whether the amelioration of insulin resistance can delay or prevent diabetes in women with limited beta-cell reserve.
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Affiliation(s)
- K Berkowitz
- Department of Medicine, University of Southern California School of Medicine, Los Angeles, USA
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Trávnícková Z, Sumová A, Peters R, Schwartz WJ, Illnerová H. Photoperiod-dependent correlation between light-induced SCN c-fos expression and resetting of circadian phase. Am J Physiol 1996; 271:R825-31. [PMID: 8897970 DOI: 10.1152/ajpregu.1996.271.4.r825] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In rodents, brief light pulses that shift the phase of the circadian locomotor rhythm also increase c-fos gene expression in the suprachiasmatic nucleus (SCN), site of an endogenous clock that regulates such rhythmicity. Because the magnitude of photic phase shifts varies when light pulses are applied at different time points over the course of the subjective night, we examined the degree of SCN c-fos gene expression after single 30-min light pulses were delivered at time points that spanned the early and late subjective night in rats maintained in either short (8:16-h light-dark cycle) or long (16:8-h light-dark cycle) photoperiods. The light-induced level of c-fos mRNA and the number of cells expressing immunoreactive c-Fos protein were measured in the SCN by in situ hybridization and immunohistochemistry, respectively, and compared with the magnitude of the corresponding phase shifts of the circadian rhythm of pineal N-acetyltransferase (NAT) activity. We found a robust correlation between c-fos photoinduction and NAT phase shifts, but this relationship was dependent on photoperiod. The degree of c-fos gene expression was strongly correlated with the magnitude of NAT phase advances and delays under the short photoperiod and with phase advances under the long photoperiod, but not with phase delays under the long photoperiod. The data suggest that c-fos gene expression in the SCN may be involved in the photic resetting of the pineal NAT rhythm. Under the long photoperiod, however, the magnitude of phase delays may be limited by the functional state of the circadian pacemaking system.
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Affiliation(s)
- Z Trávnícková
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 4, Czech Republic
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245
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Abstract
Fluorescence microphotolysis was combined with confocal laser-scanning microscopy to yield a method, herein referred to as line-scanning microphotolysis (LINESCAMP), for the measurement of molecular transport at a lateral resolution of approximately 0.34 microns and a temporal resolution of approximately 0.5 ms. A confocal microscope was operated in the line scan mode, while the laser beam power could be switched during scanning between low monitoring and high photolysing levels in less then a microsecond. The number and location of line segments to be photolysed could be freely determined. The length of the photolysed segments could be also chosen and was only limited by diffraction. Together with instrumentation a new, completely general, theoretical framework for the evaluation of diffusion measurements was developed. Based on the numerical simulation of diffusion processes employing a modified Crank-Nicholson scheme, the theory could be applied to any photobleaching geometry and profile as the initial condition and took into account the convolution with the microscope point spread function. With small diffraction-limited areas, the method yielded accurate values for diffusion coefficients in the range between approximately 10(-4) and 1 micron2 s-1. A first application of the method to the diffusion of a fluorescently labeled tracer inside the cell nucleus showed the potential of the method for the study of complex biological systems.
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Affiliation(s)
- P Wedekind
- Institut für Medizinische Physik und Biophysik, Westfälische Wilhelms-Universität, Münster, Germany.
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246
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Peters R. Australia's new gun laws: preventing the backslide. Aust N Z J Public Health 1996; 20:339-40. [PMID: 8908750 DOI: 10.1111/j.1467-842x.1996.tb01039.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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247
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France R, Culbert H, Peters R. Decreased Carbon and Nutrient Input to Boreal Lakes from Particulate Organic Matter Following Riparian Clear-Cutting. Environ Manage 1996; 20:579-583. [PMID: 8661623 DOI: 10.1007/bf01474657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The plankton communities of oligotrophic Canadian Shield lakes are strongly regulated by the allochthonous supply of total phosphorus (TP) and dissolved organic carbon (DOC), a proportion of both of which originate from particulate organic matter. Although decreased inputs of allochthonous leaf litter have been documented for small streams whose riparian forests have been removed, no such data exist for boreal lakes. Through estimates of airborne litter input from forested and clear-cut shorelines and laboratory measurements of concentrations released from leaf leachate, we determined that riparian deforestation resulted in reductions of DOC from 17.8 to 0.4 g/m shoreline/yr and of TP from 2.9 to 0.3 g/m shoreline/yr. Previous predictive models indicate that such reductions may be substantial enough to decrease basic metabolic processes of lake plankton communities by as much as 9% in primary production and 17% in respiration.
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Affiliation(s)
- R France
- Department of Biology, McGill University, 1205 Ave. Dr. Penfield, Montreal, Quebec H3A 1B1, Canada
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248
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Kubitscheck U, Tschödrich-Rotter M, Wedekind P, Peters R. Two-photon scanning microphotolysis for three-dimensional data storage and biological transport measurements. J Microsc 1996; 182:225-33. [PMID: 8801360 DOI: 10.1046/j.1365-2818.1996.60424.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Scanning microphotolysis is a method that permits the user to select, within the scanning field of a confocal microscope, areas of arbitrary geometry for photobleaching or photoactivation. Two-photon absorption, by contrast, confers on laser scanning microscopy a true spatial selectivity by restricting excitation to very small focal volumes. In the present study the two methods were combined by complementing a laser scanning microscope with both a fast programmable optical switch and a titan sapphire laser. The efficiency and accuracy of fluorescence photobleaching induced by two-photon absorption were determined using fluorescein-containing polyacrylamide gels. At optimal conditions a single scan was sufficient to reduce the gel fluorescence by approximately 40%. Under these conditions the spatial accuracy of photobleaching was 0.5 +/- 0.1 micron in the lateral (x.y) and 3.5 +/- 0.5 micron in the axial (z) direction, without deconvolution accounting for the optical resolution. Deconvolution improved the accuracy values by approximately 30%. The method was applied to write complex three-dimensional patterns into thick gels by successively scanning many closely spaced layers, each according to an individual image mask. Membrane transport was studied in a model tissue consisting of human erythrocyte ghosts carrying large transmembrane pores and packed into three-dimensional arrays. Upon equilibration with a fluorescent transport substrate single ghosts could be selectively photobleached and the influx of fresh transport substrate be monitored. The results suggest that two-photon scanning microphotolysis provides new possibilities for the optical analysis and manipulation of both technical and biological microsystems.
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Affiliation(s)
- U Kubitscheck
- Institut für Medizinische Physik und Biophysik, Westfälische Wilhelms-Universität, Münster, Germany
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249
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Chen J, Peters R, Saha P, Lee P, Theodoras A, Pagano M, Wagner G, Dutta A. A 39 amino acid fragment of the cell cycle regulator p21 is sufficient to bind PCNA and partially inhibit DNA replication in vivo. Nucleic Acids Res 1996; 24:1727-33. [PMID: 8649992 PMCID: PMC145832 DOI: 10.1093/nar/24.9.1727] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The cell cycle regulator p21 interacts with and inhibits the DNA replication and repair factor proliferating cell nuclear antigen (PCNA). We have defined a 39 amino acid fragment of p21 which is sufficient to bind PCNA with high affinity (Kd 10-20 nM). This peptide can inhibit DNA replication in vitro and microinjection of a GST fusion protein containing this domain inhibited S phase in vivo. Despite its high affinity for PCNA, the free 39 amino acid peptide does not have a well-defined structure, as judged from circular dichroism and nuclear magnetic resonance measurements, suggesting an induced fit mechanism for the PCNA-p21 interaction. The association of the small peptide with PCNA was thermolabile, suggesting that portions of p21 adjoining the minimal region of contact stabilize the interaction. In addition, a domain containing 67 amino acids from the N-terminus of PCNA was defined as both necessary and sufficient for binding to p21.
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Affiliation(s)
- J Chen
- Department of Pathology, Division of Molecular Oncology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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250
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Abstract
How nuclear pore complexes, mediating the transport of nucleic acids, proteins, and metabolites between cell nucleus and cytoplasm, are arranged in the nuclear envelope is essentially unknown. Here we describe a method combining high-resolution confocal imaging with image processing and pattern recognition to visualize single nuclear pore complexes (120 nm diameter), determine their relative positions with nanometer accuracy, and analyze their distribution in situ. The method was tested by means of a model system in which the very same sample areas could be imaged by confocal and electron microscopy. It was thus found that single fluorescent beads of 105 nm nominal diameter could be localized with a lateral accuracy of <20 nm and an axial accuracy of approximately 20 nm. The method was applied to digitonin-permeabilized 3T3 cells, whose nuclear pore complexes were fluorescently labeled with the anti-nucleoporin antibody mAb414. Stacks of optical sections were generated by confocal imaging at high resolution. Herein the nuclear pore complexes appeared as bright diffraction-limited spots whose centers were localized by fitting them by three-dimensional gaussians. The nearest-neighbor distribution function and the pair correlation function were calculated and found to agree well with those of randomly distributed hard cylinders of 138 +/- 17 nm diameter, but not with those of randomly distributed points or nonrandomly distributed cylinders. This was supported by a cluster analysis. Implications for the direct observation of the transport of single particles and molecules through individual nuclear pore complexes are discussed.
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Affiliation(s)
- U Kubitscheck
- Institut für Medizinische Physik und Biophysik, Westfälische Wilhelms-Universität, Munster, Germany
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