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Anderson S, Murray IP, Scott MR, Tweddle EJ, Gately MP, Cubukcu AA. 141 STRESS ECHOCARDIOGRAPHY IN A DISTRICT GENERAL HOSPITAL SETTING: OUTCOMES AND RELATION TO NICE GUIDELINES OF STABLE CHEST PAIN OF RECENT ONSET. Heart 2013. [DOI: 10.1136/heartjnl-2013-304019.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Elliot DSJ, Baker PA, Scott MR, Birch CW, Thompson JMD. A reply. Anaesthesia 2011. [DOI: 10.1111/j.1365-2044.2011.06731_2.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Elliott DSJ, Baker PA, Scott MR, Birch CW, Thompson JMD. ORIGINAL ARTICLE: Accuracy of surface landmark identification for cannula cricothyroidotomy. Anaesthesia 2010; 65:889-94. [DOI: 10.1111/j.1365-2044.2010.06425.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Surface sediment samples in the Laptev Sea have average 137Cs content of 7.1 Bq kg(-1), a value intermediate between that of the western Kara Sea (23 Bq kg(-1) and the East Siberian Sea (4.2 Bq kg-'). Both surface sediment content and sediment inventory of 137Cs in the Laptev Sea sediments show significant variability, and the influence of a variety of environmental factors.137Cs concentrations in the Laptev Sea surface sediments range from 0.8 to 16 Bq kg(-1). There is a marked increase in 137Cs content of surface sediment samples collected near the Lena River delta, and a local enrichment in the 137Cs inventories at these sites is also evident. Fine-grained mixed-layer illite/ smectite rich sediments in the estuary provide effective adsorption sites to fix 137Cs, in spite of desorption processes associated with low salinities in estuarine mixing. The Lena River-Laptev Sea mixing zone is a major site of sea-ice production. River and shelf sediments are incorporated into sea-ice formed in this region (Holmes and Creager, 1974). The irregular 137Cs activity profiles of the Lena River estuary cores indicate disturbance or removal of 137Cs-laden sediments via sea-ice related processes. Lena River and Estuary sediments may have served as a secondary source (i.e. other than direct fallout) of 137Cs in sea-ice. North-east of the Lena River estuary, sediment contains a thin layer of 137Cs-bearing material over an erosion surface. The 137Cs-laden surface layer may be the result of transient deposition of estuarine sediments being delivered by sea-ice or spring floods.
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Affiliation(s)
- A Johnson-Pyrtle
- Department of Oceanography, Texas A&M University, College Station TX 77843-3146, USA
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Peretz D, Scott MR, Groth D, Williamson RA, Burton DR, Cohen FE, Prusiner SB. Strain-specified relative conformational stability of the scrapie prion protein. Protein Sci 2001; 10:854-63. [PMID: 11274476 PMCID: PMC2373967 DOI: 10.1110/ps.39201] [Citation(s) in RCA: 211] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2000] [Revised: 01/23/2001] [Accepted: 01/23/2001] [Indexed: 10/14/2022]
Abstract
Studies of prion biology and diseases have elucidated several new concepts, but none was more heretical than the proposal that the biological properties that distinguish different prion strains are enciphered in the disease-causing prion protein (PrP(Sc)). To explore this postulate, we examined the properties of PrP(Sc) from eight prion isolates that propagate in Syrian hamster (SHa). Using resistance to protease digestion as a marker for the undenatured protein, we examined the conformational stabilities of these PrP(Sc) molecules. All eight isolates showed sigmoidal patterns of transition from native to denatured PrP(Sc) as a function of increasing guanidine hydrochloride (GdnHCl) concentration. Half-maximal denaturation occurred at a mean value of 1.48 M GdnHCl for the Sc237, HY, SHa(Me7), and MT-C5 isolates, all of which have approximately 75-d incubation periods; a concentration of 1.08 M was found for the DY strain with a approximately 170-d incubation period and approximately 1.25 M for the SHa(RML) and 139H isolates with approximately 180-d incubation periods. A mean value of 1.39 M GdnHCl for the Me7-H strain with a approximately 320-d incubation period was found. Based on these results, the eight prion strains segregated into four distinct groups. Our results support the unorthodox proposal that distinct PrP(Sc) conformers encipher the biological properties of prion strains.
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Affiliation(s)
- D Peretz
- Institute for Neurodegenerative Diseases, University of California, San Francisco, California 94143, USA
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Abstract
Branched polyamines, including polyamidoamine and polypropyleneimine (PPI) dendrimers, are able to purge PrP(Sc), the disease-causing isoform of the prion protein, from scrapie-infected neuroblastoma (ScN2a) cells in culture (S. Supattapone, H.-O. B. Nguyen, F. E. Cohen, S. B. Prusiner, and M. R. Scott, Proc. Natl. Acad. Sci. USA 96:14529-14534, 1999). We now demonstrate that exposure of ScN2a cells to 3 microg of PPI generation 4.0/ml for 4 weeks not only reduced PrP(Sc) to a level undetectable by Western blot but also eradicated prion infectivity as determined by a bioassay in mice. Exposure of purified RML prions to branched polyamines in vitro disaggregated the prion rods, reduced the beta-sheet content of PrP 27-30, and rendered PrP 27-30 susceptible to proteolysis. The susceptibility of PrP(Sc) to proteolytic digestion induced by branched polyamines in vitro was strain dependent. Notably, PrP(Sc) from bovine spongiform encephalopathy-infected brain was susceptible to PPI-mediated denaturation in vitro, whereas PrP(Sc) from natural sheep scrapie-infected brain was resistant. Fluorescein-labeled PPI accumulated specifically in lysosomes, suggesting that branched polyamines act within this acidic compartment to mediate PrP(Sc) clearance. Branched polyamines are the first class of compounds shown to cure prion infection in living cells and may prove useful as therapeutic, disinfecting, and strain-typing reagents for prion diseases.
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Affiliation(s)
- S Supattapone
- Institute for Neurodegenerative Diseases, University of California at San Francisco, San Francisco, California 94143, USA
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Supattapone S, Muramoto T, Legname G, Mehlhorn I, Cohen FE, DeArmond SJ, Prusiner SB, Scott MR. Identification of two prion protein regions that modify scrapie incubation time. J Virol 2001; 75:1408-13. [PMID: 11152514 PMCID: PMC114047 DOI: 10.1128/jvi.75.3.1408-1413.2001] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [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: 11/20/2022] Open
Abstract
A series of prion transmission experiments was performed in transgenic (Tg) mice expressing either wild-type, chimeric, or truncated prion protein (PrP) molecules. Following inoculation with Rocky Mountain Laboratory (RML) murine prions, scrapie incubation times for Tg(MoPrP)4053, Tg(MHM2)294/Prnp(0/0), and Tg(MoPrP, Delta23-88)9949/Prnp(0/0) mice were approximately 50, 120, and 160 days, respectively. Similar scrapie incubation times were obtained after inoculation of these lines of Tg mice with either MHM2(MHM2(RML)) or MoPrP(Delta23-88)(RML) prions, excluding the possibility that sequence-dependent transmission barriers could account for the observed differences. Tg(MHM2)294/Prnp(0/0) mice displayed prolonged scrapie incubation times with four different strains of murine prions. These data provide evidence that the N terminus of MoPrP and the chimeric region of MHM2 PrP (residues 108 through 111) both influence the inherent efficiency of prion propagation.
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Affiliation(s)
- S Supattapone
- Institute for Neurodegenerative Diseases, University of California, San Francisco, California 94143, USA
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Johnson-Pyrtle A, Scott MR, Laing TE, Smol JP. 137Cs distribution and geochemistry of Lena River (Siberia) drainage basin lake sediments. Sci Total Environ 2000; 255:145-59. [PMID: 10898402 DOI: 10.1016/s0048-9697(00)00466-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
The Lena River is the second largest river that discharges into the Arctic Ocean. It is therefore important to determine not only the direct impact its discharge has on the 137Cs concentration of the Arctic, but also the potential its drainage basin has as a 137Cs source. 137Cs surface sediment concentrations and inventory values, which range from 4.97 to 338 Bq kg(-1) and 357 to 1732 Bq m(-2), respectively, were determined for the Lena River drainage basin lake samples, via gamma analysis. The average geochemical and mineralogical composition of a subset of samples was also determined using neutron activation analysis, X-ray diffraction and X-ray fluorescence spectrometry techniques. Results of these geochemical analyses allowed for the identification of key geochemical factors that influence the distribution of 137Cs in the Lena River drainage basin. 137Cs profiles indicate that Lena River drainage basin lacustrine sediments serve as a record of 137Cs fallout. Based on the downcore 137Cs, %illite, %smectite, %Al and %Mn distribution patterns, it was concluded that a small fraction of non-selectively bound 137Cs was remobilized at depth in some cores. Inconsistencies between the actual 137Cs fallout record and the 137Cs profiles determined for the lake sediments were attributed to 137Cs remobilization in subsurface sediments. In addition to establishing the agreement between the global atmospheric fallout record and the downcore 137Cs distribution patterns determined for these sediments, results indicate that 137Cs deposited during periods of maximum atmospheric release was buried and is not susceptible to surface erosion processes. However, mean 137Cs concentrations of the lacustrine surface sediments (125 Bq kg(-1)) are still significantly higher than those of the nearby Lena River estuary (11.22 Bq kg(-1)) and Laptev Sea (6.00 Bq kg(-1)). Our study suggests that the Lena River drainage basin has the potential to serve as a source of 137Cs to the adjacent Arctic Ocean.
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Affiliation(s)
- A Johnson-Pyrtle
- Department of Oceanography M/S 3146, Texas A&M University, College Station 77843-3146, USA.
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Abstract
There is growing concern that bovine spongiform encephalopathy (BSE) may have passed from cattle to humans, resulting in approximately 70 cases of an atypical, variant CJD (vCJD) in teenagers and young adults. We report here that transgenic (Tg) mice expressing full-length bovine (Bo) PrP serially propagate BSE prions and that there is no species barrier for transmission from cattle to Tg(BoPrP) mice. Surprisingly, these same mice were also highly susceptible to vCJD and natural sheep scrapie. The incubation times (approximately 250 d), neuropathology, and PrP(Sc) isoforms in Tg(BoPrP) mice inoculated with vCJD and BSE brain extracts were indistinguishable and differed dramatically from those seen in these mice injected with natural scrapie. In efforts to identify PrP sequences required for prion formation, we found that a redacted prion protein of only 106 amino acids (PrP106) containing two large deletions supported prion propagation. In Tg(PrP106) mice, an artificial transmission barrier for the passage of full-length mouse prions was diminished by the coexpression of full-length wt MoPrP(C), suggesting that wt MoPrP acts in trans to accelerate the replication of "miniprions" containing PrP(Sc)106. Following a single passage (approximately 300 d) in Tg(PrP106) mice, the miniprions efficiently transmitted disease to Tg(PrP106) mice after only approximately 66 days. Our findings with Tg(BoPrP) mice provide compelling evidence that prions from cattle with BSE have infected humans and caused fatal neurodegeneration, the unique features of miniprions offer new insights into the mechanism of prion replication, and the trans-acting effects of full-length PrP coexpression suggest a new approach to the development of even more efficient animal models for prion diseases.
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Affiliation(s)
- M R Scott
- Institute for Neurodegenerative Diseases, Department of Neurology, University of California, San Francisco 94143-0518, USA
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Scott MR, Will R, Ironside J, Nguyen HO, Tremblay P, DeArmond SJ, Prusiner SB. Compelling transgenetic evidence for transmission of bovine spongiform encephalopathy prions to humans. Proc Natl Acad Sci U S A 1999; 96:15137-42. [PMID: 10611351 PMCID: PMC24786 DOI: 10.1073/pnas.96.26.15137] [Citation(s) in RCA: 439] [Impact Index Per Article: 17.6] [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: 11/18/2022] Open
Abstract
There is growing concern that bovine spongiform encephalopathy (BSE) may have passed from cattle to humans. We report here that transgenic (Tg) mice expressing bovine (Bo) prion protein (PrP) serially propagate BSE prions and that there is no species barrier for transmission from cattle to Tg(BoPrP) mice. These same mice were also highly susceptible to a new variant of Creutzfeldt-Jakob disease (nvCJD) and natural sheep scrapie. The incubation times (approximately 250 days), neuropathology, and disease-causing PrP isoforms in Tg(BoPrP)Prnp(0/0) mice inoculated with nvCJD and BSE brain extracts were indistinguishable and differed dramatically from those seen in these mice injected with natural scrapie prions. Our findings provide the most compelling evidence to date that prions from cattle with BSE have infected humans and caused fatal neurodegeneration.
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Affiliation(s)
- M R Scott
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143, USA
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Abstract
We report that branched polyamines, including polyamidoamide dendimers, polypropyleneimine, and polyethyleneimine, are able to purge PrP(Sc), the protease-resistant isoform of the prion protein, from scrapie-infected neuroblastoma (ScN2a) cells in culture. The removal of PrP(Sc) by these compounds depends on both the concentration of branched polymer and the duration of exposure. Chronic exposure of ScN2a cells to low noncytotoxic concentrations of branched polyamines for 1 wk reduced PrP(Sc) to an undetectable level, a condition that persisted at least 3 wk after removal of the compound. Structure-activity analysis revealed that a high surface density of primary amino groups is required for polyamines to eliminate PrP(Sc) effectively from cells. The removal of PrP(Sc) by branched polyamines is attenuated by chloroquine in living cells, and exposure of scrapie-infected brain extracts with branched polyamines at acidic pH rendered the PrP(Sc) susceptible to protease in vitro, suggesting that endosomes or lysozomes may be the site of action. Our studies suggest that branched polyamines might be useful therapeutic agents for treatment of prion diseases and perhaps a variety of other degenerative disorders.
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Affiliation(s)
- S Supattapone
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143-0518, USA
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Affiliation(s)
- S B Prusiner
- Department of Neurology, University of California, San Francisco 94143, USA
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Hegde RS, Mastrianni JA, Scott MR, DeFea KA, Tremblay P, Torchia M, DeArmond SJ, Prusiner SB, Lingappa VR. A transmembrane form of the prion protein in neurodegenerative disease. Science 1998; 279:827-34. [PMID: 9452375 DOI: 10.1126/science.279.5352.827] [Citation(s) in RCA: 516] [Impact Index Per Article: 19.8] [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: 02/06/2023]
Abstract
At the endoplasmic reticulum membrane, the prion protein (PrP) can be synthesized in several topological forms. The role of these different forms was explored with transgenic mice expressing PrP mutations that alter the relative ratios of the topological forms. Expression of a particular transmembrane form (termed CtmPrP) produced neurodegenerative changes in mice similar to those of some genetic prion diseases. Brains from these mice contained CtmPrP but not PrPSc, the PrP isoform responsible for transmission of prion diseases. Furthermore, in one heritable prion disease of humans, brain tissue contained CtmPrP but not PrPSc. Thus, aberrant regulation of protein biogenesis and topology at the endoplasmic reticulum can result in neurodegeneration.
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Affiliation(s)
- R S Hegde
- Department of Physiology, University of California, San Francisco, CA 94143-0444, USA
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Abstract
Prions are unprecedented infectious pathogens that cause a group of invariably fatal, neurodegenerative diseases by an entirely novel mechanism. Prion diseases may present as genetic, infectious, or sporadic disorders, all of which involve modification of the prion protein (PrP). The human prion disease Creutzfeldt-Jakob disease (CJD) generally presents as a progressive dementia, whereas scrapie of sheep and bovine spongiform encephalopathy (BSE) are manifest as ataxic illnesses. Prions are devoid of nucleic acid and seem to be composed exclusively of a modified isoform of PrP designated PrPSc. The normal, cellular PrP designated PrPC is converted into PrPSc through a process whereby some of its alpha-helical structure is converted into beta-sheet. The species of a particular prion is encoded by the sequence of the chromosomal PrP gene of the mammals in which it last replicated. In contrast to pathogens with a nucleic acid genome, prions encipher strain-specific properties in the tertiary structure of PrPSc. Transgenetic studies argue that PrPSc acts as a template upon which PrPC is refolded into a nascent PrPSc molecule through a process facilitated by another protein.
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Affiliation(s)
- S B Prusiner
- Department of Neurology, University of California, San Francisco 94143, USA
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Scott MR, Safar J, Telling G, Nguyen O, Groth D, Torchia M, Koehler R, Tremblay P, Walther D, Cohen FE, DeArmond SJ, Prusiner SB. Identification of a prion protein epitope modulating transmission of bovine spongiform encephalopathy prions to transgenic mice. Proc Natl Acad Sci U S A 1997; 94:14279-84. [PMID: 9405603 PMCID: PMC24939 DOI: 10.1073/pnas.94.26.14279] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/1997] [Indexed: 02/05/2023] Open
Abstract
There is considerable concern that bovine prions from cattle with bovine spongiform encephalopathy (BSE) may have been passed to humans (Hu), resulting in a new form of Creutzfeldt-Jakob disease (CJD). We report here the transmission of bovine (Bo) prions to transgenic (Tg) mice expressing BoPrP; one Tg line exhibited incubation times of approximately 200 days. Like most cattle with BSE, vacuolation and astrocytic gliosis were confined in the brainstems of these Tg mice. Unexpectedly, mice expressing a chimeric Bo/Mo PrP transgene were resistant to BSE prions whereas mice expressing Hu or Hu/Mo PrP transgenes were susceptible to Hu prions. A comparison of differences in Mo, Bo, and Hu residues within the C terminus of PrP defines an epitope that modulates conversion of PrPC into PrPSc and, as such, controls prion transmission across species. Development of susceptible Tg(BoPrP) mice provides a means of measuring bovine prions that may prove critical in minimizing future human exposure.
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Affiliation(s)
- M R Scott
- Department of Neurology, University of California, San Francisco, CA 94143, USA
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Abstract
Two prion strains with identical incubation periods in mice exhibited distinct incubation periods and different neuropathological profiles upon serial transmission to transgenic mice expressing chimeric Syrian hamster/mouse (MH2M) prion protein (PrP) genes [Tg(MH2M) mice] and subsequent transmission to Syrian hamsters. After transmission to Syrian hamsters, the Me7 strain was indistinguishable from the previously established Syrian hamster strain Sc237, despite having been derived from an independent ancestral source. This apparent convergence suggests that prion diversity may be limited. The Me7 mouse strain could also be transmitted directly to Syrian hamsters, but when derived in this way, its properties were distinct from those of Me7 passaged through Tg(MH2M) mice. The Me7 strain did not appear permanently altered in either case, since the original incubation period could be restored by effectively reversing the series of passages. Prion diversity enciphered in the conformation of the scrapie isoform of PrP (PrP(Sc)) (G. C. Telling et al., Science 274:2079-2082, 1996) seems to be limited by the sequence of the PrP substrates serially converted into PrP(Sc), while prions are propagated through interactions between the cellular and scrapie isoforms of PrP.
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Affiliation(s)
- M R Scott
- Department of Neurology, University of California, San Francisco 94143, USA
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DeArmond SJ, Sánchez H, Yehiely F, Qiu Y, Ninchak-Casey A, Daggett V, Camerino AP, Cayetano J, Rogers M, Groth D, Torchia M, Tremblay P, Scott MR, Cohen FE, Prusiner SB. Selective neuronal targeting in prion disease. Neuron 1997; 19:1337-48. [PMID: 9427256 DOI: 10.1016/s0896-6273(00)80424-9] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.1] [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: 02/05/2023]
Abstract
The pattern of scrapie prion protein (PrP(Sc)) accumulation in the brain is different for each prion strain. We tested whether the PrP(Sc) deposition pattern is influenced by the Asn-linked oligosaccharides of PrP(C) in transgenic mice. Deletion of the first oligosaccharide altered PrP(C) trafficking and prevented infection with two prion strains. Deletion of the second did not alter PrP(C) trafficking, permitted infection with one prion strain, and had a profound effect on the PrP(Sc) deposition pattern. Our data raise the possibility that glycosylation can modify the conformation of PrP(C). Glycosylation could affect the affinity of PrP(C) for a particular conformer of PrP(Sc), thereby determining the rate of nascent PrP(Sc) formation and the specific patterns of PrP(Sc) deposition.
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Affiliation(s)
- S J DeArmond
- Department of Pathology, University of California, San Francisco 94143, USA
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Abstract
OBJECTIVE To examine the psychometrics of neurological soft signs in young children. METHOD In a sample of 42 children from the community, two examiners simultaneously rated soft signs using a standardized examination. A subsample (n = 33) was reexamined twice over the next week to estimate test-retest reliability. RESULTS Total score exhibited acceptable internal consistency as well as interrater and test-retest reliability. Psychometrics for individual items appeared less satisfactory than for the total score. DISCUSSION Although examiners can reliably rate a variety of soft signs, more research examining test-retest reliability is needed. A reliable examination might be useful in future efforts to document the neuropsychiatric correlates of soft signs.
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Affiliation(s)
- D S Pine
- Department of Child and Adolescent Psychiatry, New York State Psychiatric Institute, New York 10032, USA
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Affiliation(s)
- M R Scott
- Department of Neurology, University of California, San Francisco 94143-0518, USA
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Scott MR. Don't "bug me:" controlling the spread of communicable diseases. J Sch Health 1994; 64:167. [PMID: 8035578 DOI: 10.1111/j.1746-1561.1994.tb03290.x] [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] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- M R Scott
- Dept. of Health Sciences, Youngstown State Univeristy, Youngstown, OH 44555-0001
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Berk HW, Larner JM, Spaulding C, Agarwal SK, Scott MR, Steiner L. Extracranial absorbed doses with Gamma Knife radiosurgery. Stereotact Funct Neurosurg 1993; 61 Suppl 1:164-72. [PMID: 8115748 DOI: 10.1159/000100670] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 01/28/2023]
Abstract
Radiosurgery is used with increasing frequency, not only for the treatment of cerebral arteriovenous malformations (AVMs), but also for the treatment of other well-defined lesions including acoustic neuromas, meningiomas, pituitary adenomas as well as solitary metastases. Although investigators have addressed dosimetric aspects of stereotactic radiosurgery in terms of target volume, little if any attention has been focused on the absorbed doses received at extracranial sites. Therefore, absorbed doses to the eye, thyroid, sternum and gonads were measured in 111 patients (100 adults and 11 children) using thermoluminescent dosimetry (TLDs). For the 100 adults, the average maximum target absorbed dose was 35 +/- 8 Gy. The measured absorbed dose in selected organs of adults from Gamma Knife radiosurgery using one or more isocenters was 9 +/- 8 cGy for the eye, 15 +/- 7 cGy for the thyroid, 20 +/- 10 cGy for the sternum and 3 +/- 2 cGy for the gonads. The absorbed doses received by the children (13 years and younger) was similar with the exception of a marked increase in gonadal dose. The use of multiple isocenters is associated with higher absorbed doses to extracranial sites.
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Affiliation(s)
- H W Berk
- Lars Leksell Center for Radiosurgery, University of Virginia Health Sciences Center, Charlottesville
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Abstract
The Dandy-Walker variant is a less severe posterior fossa anomaly than the classic Dandy-Walker malformation. In 17 consecutive fetuses, the Dandy-Walker variant was diagnosed at sonography, and associated defects, karyotypic anomalies, and outcomes were evaluated. Four of the 17 fetuses (24%) had mild ventriculomegaly. Eight of the 17 (47%) had concurrent non-central nervous system (CNS) anomalies. Five fetuses (29%) had an abnormal karyotype (two with trisomy 18, one each with trisomy 13, 21, and 11q+) and associated sonographic anomalies. Six of the 17 fetuses (35%) died in utero or during the neonatal period, two are severely handicapped, and the other nine are developing normally at ages 4 months to 4 years. Six of the nine normally developing infants (53%) lacked non-CNS sonographic findings. Because the prognosis is uncertain for an infant born with the prenatal diagnosis of Dandy-Walker variant, prenatal recognition of the anomaly allows for the option of fetal karyotyping and for arrangement for postnatal follow-up.
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Affiliation(s)
- J A Estroff
- Department of Radiology, Children's Hospital, Harvard Medical School, Boston, MA
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Gelber CN, Scott MR. Ipsilateral synchronous ductal and colloid breast carcinomas with mammographic correlation. Australas Radiol 1992; 36:330-1. [PMID: 1338561 DOI: 10.1111/j.1440-1673.1992.tb03213.x] [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] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- C N Gelber
- Radiology Department, St. Vincent's Hospital, Victoria Parade, Fitzroy, Australia
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Abstract
The efficient expression of exogenous prion protein (PrP) molecules in mouse neuroblastoma cells that are chronically infected with murine scrapie prions (ScN2a cells; Butler, D.A., et al., 1988, J. Virol. 62, 1558-1564) and in transgenic mice is described. This technology allows investigation of the PrP molecule for structural regions involved in determining species specificity, as well as ablation experiments designed to address the functionality of particular regions of the PrP molecule. Previous reports demonstrated that the PrP gene specifies the host range for susceptibility of transgenic animals to prions (Scott, M., et al., 1989, Cell 59, 847-857; Prusiner, S.B., et al., 1990, Cell 63, 673-686). Consistent with these results, we showed that Syrian hamster (SHa) PrP is ineligible for efficient conversion to PrPSc in ScN2a cells. By constructing a series of chimeric mouse (Mo)/SHaPrP genes, we developed an epitopically tagged functional variant of the MoPrP gene, which can efficiently form protease-resistant PrP molecules upon expression in ScN2a cells. The presence of a defined epitope for an SHa-specific monoclonal antibody allows the products of this chimeric gene to be discriminated from endogenous MoPrP and creates a useful reagent for exploring structure/function relationships via targeted mutagenesis. In addition, we developed a transgenic mouse expression vector by manipulation of an SHaPrP cosmid clone. This vector permits the efficient expression of foreign PrP genes in the brains of transgenic animals, enabling pathological consequences of in vitro mutagenesis to be studied.
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Affiliation(s)
- M R Scott
- Department of Neurology, University of California, San Francisco 94143
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Butler DA, Scott MR, Bockman JM, Borchelt DR, Taraboulos A, Hsiao KK, Kingsbury DT, Prusiner SB. Scrapie-infected murine neuroblastoma cells produce protease-resistant prion proteins. J Virol 1988; 62:1558-64. [PMID: 3282080 PMCID: PMC253182 DOI: 10.1128/jvi.62.5.1558-1564.1988] [Citation(s) in RCA: 317] [Impact Index Per Article: 8.8] [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: 01/05/2023] Open
Abstract
Scrapie and Creutzfeldt-Jakob disease are transmissible, degenerative neurological diseases caused by prions. Considerable evidence argues that prions contain protease-resistant sialoglycoproteins, designated PrPSc, encoded by a cellular gene. The prion protein (PrP) gene also encodes a normal cellular protein designated PrPC. We established clonal cell lines which support the replication of mouse scrapie or Creutzfeldt-Jakob disease prions. Mouse neuroblastoma N2a cells were exposed to mouse scrapie prions and subsequently cloned. After limited proteinase K digestion, three PrP-immunoreactive proteins with apparent molecular masses ranging between 20 and 30 kilodaltons were detected in extracts of scrapie-infected N2a cells by Western (immuno-) blotting. The authenticity of these PrPSc molecules was established by using monospecific antiserum raised against a synthetic peptide corresponding to a portion of the prion protein. Those clones synthesizing PrPSc molecules possessed scrapie prion infectivity as measured by bioassay; clones without PrPSc failed to demonstrate infectivity. Detection of PrPSc molecules in scrapie-infected N2a cells supports the contention that PrPSc is a component of the infectious scrapie particle and opens new approaches to the study of prion diseases.
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Affiliation(s)
- D A Butler
- Department of Neurology, University of California, San Francisco 94143-0518
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Abstract
A single copy gene encodes both the scrapie (PrPSc) and cellular (PrPC) isoforms of the prion protein (PrP). Cultured cell lines were found to express the endogenous PrP mRNA at levels comparable to those observed in the brains of adult rodents; however, these cells were invariably found to express greatly reduced levels of PrP. In all the cell lines examined, PrP was undetectable by Western immunoblot analysis. These cells were also poor recipients for expression constructs linking the hamster PrP gene open reading frame to several strong eukaryotic promoters; stable clones derived by transfection of these expression vectors failed to show elevated expression of PrP. When extremely high levels of PrP mRNA were produced using either an insect baculovirus or a mammalian SV40 based vector, significant quantities of PrP were produced, although in both cases the proteins were apparently processed differently from the PrPC observed in brains. In an expression system using an SV40 late promoter vector in monkey COS-7 cells, a significant fraction of PrP was transported to the cell surface where PrPC is found in vivo. PrP synthesized by the baculovirus vector failed to induce scrapie in hamsters and did not possess the characteristics of the PrPSc isoform associated with infectivity. The SV40 late promoter vector system may permit experiments designed to elucidate the role of PrPSc during scrapie infection as well as the function of PrPC in normal metabolism.
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Affiliation(s)
- M R Scott
- Department of Neurology, University of California, San Francisco 94143
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Abstract
We have used molecular hybridization and cDNA cloning techniques to isolate mouse cellular genes activated in SV40-transformed cells and we show that many of the clones belong to one of four sets. We characterize the cytoplasmic transcripts and genomic sequences homologous to two of these sets. The Set 1 transcription unit(s) is activated in all SV40-transformed cell lines analyzed, and experiments with tsA-mutant-transformed lines show that activation appears to require functional large T-antigen. This transcription unit(s) is also activated in mouse fibroblasts transformed by other agents, including retroviruses and chemical carcinogens. Activation of the Set 2 transcription unit(s) is more restricted, being confined to cell lines transformed by SV40 and retroviruses with distinctive biological properties.
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Scott MR, Brickell PM, Latchman DS, Murphy D, Westphal KH, Rigby PW. The use of cDNA cloning techniques to isolate genes activated in tumour cells. Haematol Blood Transfus 1983; 28:236-40. [PMID: 6305792 DOI: 10.1007/978-3-642-68761-7_45] [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] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Abstract
We have constructed and characterised a series of approved, disabled cosmid vectors which we call Homer cosmids and have examined the optimal conditions for the construction of libraries of eukaryotic DNA segments using these vectors. Analysis of these libraries shows that most of the sequences we have tested for are present at the expected frequency and that the libraries can be stably propagated. We have also directly tested the stability of cosmid clones carrying tandemly repeated inserts. This work shows that it should be possible to clone most eukaryotic genes using cosmid vectors and that such cloning systems have considerable advantages over those more commonly used.
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Sachdev Y, Scott MR, Clayton CB, Hall R. Technetium-99m uptake in the assessment of hyperthyroidism. J Assoc Physicians India 1976; 24:649-54. [PMID: 1025106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Tidd MJ, Gow JG, Pennington JH, Shelton J, Scott MR. Comparison of hydrophilic polymer-coated latex, uncoated latex and PVC indwelling balloon catheters in the prevention of urinary infection. Br J Urol 1976; 48:285-91. [PMID: 963410 DOI: 10.1111/j.1464-410x.1976.tb03023.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Latex, hydrophilic polymer-coated latex and PVC balloon indwelling urethral catheters were compared in respect of the urinary tract infections arising in association with their use in male patients. The polymer (Hydron) coating conferred no benefit over uncoated latex which in turn was indistinguishable from PVC. No significant differences in the spectra of infecting organismns were observed between the 3 catheter types.
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Scott MR, Frederik WS. Electronic data processing (EDP) and multiphasic health screening. J Occup Med 1972; 14:457-61. [PMID: 5057212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Frederik WS, Scott MR. Medical statistics, system monitoring and provisional normals. J Occup Med 1972; 14:466-71. [PMID: 5057214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Halbleib JA, Scott MR. Theoretical Neutron Production from Hydrogen Isotope Reactions. NUCL SCI ENG 1969. [DOI: 10.13182/nse69-a20687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Turekian KK, Scott MR. Concentrations of chromium, silver, molybdenum, nickel, cobalt, and manganese in suspended material in streams. Environ Sci Technol 1967; 1:940-942. [PMID: 22148411 DOI: 10.1021/es60011a001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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