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Lewis AM. Neurologic emergency! Nursing 1999; 29:54-6. [PMID: 10797674 DOI: 10.1097/00152193-199910000-00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
This paper is a review of isolation and containment models, policies and procedures. The arguments for and against various practices are outlined. The psychological effects of isolating patients in single rooms and new ideas for staff intervention are discussed. A modern, flexible approach is suggested.
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Lewis AM, Mathieu-Costello O, McMillan PJ, Gilbert RD. Effects of long-term, high-altitude hypoxia on the capillarity of the ovine fetal heart. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H756-62. [PMID: 10444503 DOI: 10.1152/ajpheart.1999.277.2.h756] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To determine the effect of chronic hypoxia on myocardial capillarity, we exposed pregnant ewes to an altitude of 3,820 m from day 30 to day 139 of gestation and compared the fetus to low-altitude (approximately 300 m) controls. We hypothesized that capillarity would increase in the hypoxic myocardium to optimize oxygen and metabolite flux to hypoxic tissues. Fetal hearts were fixed by retrograde aortic perfusion and processed for microscopy and stereological evaluation. Fiber cross-sectional area and capillary density were measured and standardized to sarcomere length. Capillary volume density and capillary diameter were measured, capillary-to-fiber ratio and capillary length density were calculated, and the capillary anisotropy coefficient was obtained from a table of known values. Capillary-to-fiber ratio, capillary volume density, and the capillary anisotropy coefficient were not different between hypoxia and control groups. Capillary diameter was significantly larger in the right compared with the left ventricle of hypoxic but not control hearts; fiber cross-sectional area tended to be larger in the right ventricle of both groups, but this was not significant. As a result of larger fiber size, capillary density and capillary length density were significantly smaller in the right ventricle of hypoxic but not control fetal hearts. Contrary to our hypothesis, the ovine fetus does not show morphological adaptation in the myocardium after approximately 109 days of high-altitude hypoxic stress.
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Lewis AM. Cardiovascular emergency! Nursing 1999; 29:49-51. [PMID: 10418508 DOI: 10.1097/00152193-199906000-00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
The tumorigenicity of adenovirus (Ad) 12-transformed mouse cells was evaluated by analyzing the relationship of tumor cell dose to tumor incidence and tumor latency. The tumor producing dose 50% endpoint values used to define these relationships remained stable during 52 weeks of serial passage in tissue culture and were not determined by low frequency events within the cell population. The data from these analyses suggest that the phenotype of Ad12-transformed mouse cells is influenced by two set of traits--those traits that determine the threshold number of cells required for tumor formation and those that extend the cell dose-dependent tumor latency period. Both traits are established independently of cell immortalization, and both can be influenced by the immunological status of tumor-challenged animals. These observations were verified by using mouse cells transformed by Ad5 and SV40. The biological and molecular processes that contribute to these traits remain to be determined. The approach developed by this analysis provides a reliable, quantitative means of evaluating endogenous traits that determine transformed cell tumorigenicity. This method can also be used to test the effects of tumor cell manipulations or changes in host response that could alter expression or detection of these neoplastic cell traits.
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Lewis AM. What it means to carry a defective gene: a moral introspection. THE PHAROS OF ALPHA OMEGA ALPHA-HONOR MEDICAL SOCIETY. ALPHA OMEGA ALPHA 1999; 61:5-10. [PMID: 9884607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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33
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Lewis AM. Managing common pediatric emergencies. Nursing 1999; 29:33-9; quiz 40. [PMID: 9987295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Abstract
Data from studies of the infectivity of DNA injected directly into laboratory animals are used to estimate the potential infectivity risk of residual DNA in biological products. The potential for some novel products to contain infectious quantities of residual cellular DNA is discussed, and further study of this subject is suggested.
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El-Bouri KW, Lewis AM, Okeahialam CA, Wright D, Tanna A, Joynson DH. A community outbreak of invasive and non-invasive group A beta-haemolytic streptococcal disease in a town in South Wales. Epidemiol Infect 1998; 121:515-21. [PMID: 10030699 PMCID: PMC2809557 DOI: 10.1017/s095026889800168x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An increase in the incidence of invasive and non-invasive infections caused by group A beta-haemolytic streptococci (GAS) was noted in and around the town of Glynneath (population approx. 4000) in West Glamorgan, South Wales between 1 January and 30 June 1995. A total of 133 cases was ascertained with 127 (96%) occurring between 1 March and 30 June 1995. Six patients had invasive disease (one died) and all presented at the peak of the outbreak. There were 127 non-invasive cases of whom 7 were hospitalized. The outbreak was investigated to determine its extent and whether it was caused by a single M-serotype of GAS. Serotyping showed that 13 different M-serotypes were involved with the M1 serotype predominating. The overall incidence of GAS invasive disease in West Glamorgan (population 365,000) increased sevenfold from a crude incidence of 0.5/10(5) per year in 1994 to 3.5/10(5) per year in 1995, but fell back to 0.75/10(5) per year in 1996. Eighty-two (80%) out of 102 individuals affected by GAS replied to a health questionnaire; sore throat was the commonest symptom reported (97%). Thirty-nine of these index cases identified at least one other member of their household who had experienced similar symptoms. The interval between the onset of illness in members of a single household was 0-83 days with a mean of 22 days. The mean duration of illness was 13.5 days and 61% of patients were treated with penicillin V for a mean duration of 9.3 days. Twenty-one per cent of GAS isolates were erythromycin-resistant and the M4 and M6 serotypes were especially resistant to erythromycin (87.5 and 100% resistance, respectively). Penicillin V failed to eradicate GAS from the throats of 25% of assessable patients. In this community, an outbreak of non-invasive disease caused by GAS was linked in time and place with an outbreak of serious invasive disease.
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Lewis AM. Open your vertical and smile: metal-free, full-mouth rehabilitation. DENTISTRY TODAY 1998; 17:64-6, 68-9. [PMID: 10752399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Lewis AM. Sealing caries out ... or in? DENTISTRY TODAY 1997; 16:104-7. [PMID: 9560620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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40
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Eyler YL, Siwarski DF, Huppi KE, Lewis AM. Downregulation of Waf1, C2, C3, and major histocompatibility complex class I loci within an 18-cM region of chromosome 17 in adenovirus-transformed mouse cells. Mol Carcinog 1997; 18:213-20. [PMID: 9142216 DOI: 10.1002/(sici)1098-2744(199704)18:4<213::aid-mc5>3.0.co;2-e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this study, the expression of the p53 tumor suppressor gene and the p53-regulated Mdm2 and Waf1 genes was evaluated in adenovirus (Ad)-transformed mouse cells. The expected levels of p53 mRNA and protein and Mdm2 mRNA were detected in all transformed cells. However, the level of Waf1 mRNA was markedly reduced in Ad12-transformed cells and in some Ad5-transformed cells. Waf1 expression was not reduced in untransformed mouse cells infected with Ad12 or Ad5. Expression of the class I major histocompatibility complex (MHC) locus was downregulated in 13 Ad-transformed cell lines (derived from four different strains of mice) that exhibited reduced expression of Waf1. Waf1 is located on mouse chromosome 17 proximal to the MHC class I locus. To determine whether other chromosome 17 genes were downregulated, the cells were examined for expression of other genetic loci. Of those tested, only the C2 and C3 complement loci were expressed in mouse fibroblasts. Expression of C2 (which is within the MHC) and expression of C3 (which is 15 cM distal to the MHC) were downregulated in those transformed cells in which Waf1 and MHC class I were downregulated. The Ad12- and Ad5-transformed cells that expressed low levels of Waf1, MHC class I, C2, and C3 formed tumors in syngeneic adult mice. These data suggest that the downregulation of multiple genes within the 32 Mb of mouse chromosome 17 that includes the Waf1 locus to the C3 locus occurs in Ad mouse-cell transformation and may contribute to the tumorigenicity of transformed cells.
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Hixon ML, Lewis AM, Levine AS, Chattopadhyay SK. Limited diversity in the major histocompatibility complex class II loci of Syrian hamster DNA. LABORATORY ANIMAL SCIENCE 1996; 46:679-81. [PMID: 9001183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Lewis AM. Aesthetic restorations for congenitally missing teeth--a case study. DENTISTRY TODAY 1996; 15:74, 76-7. [PMID: 9567130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Renfree MB, Lewis AM. Cleavage in vivo and in vitro in the Marsupial Macropus eugenii. Reprod Fertil Dev 1996; 8:725-42. [PMID: 8870094 DOI: 10.1071/rd9960725] [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: 02/02/2023] Open
Abstract
In the tammar wallaby, transport down the oviduct takes less than 24 h after fertilization and a mucoid coat is deposited within a few hours of fertilization, with excess spermatozoa trapped in the mucoid layer. The mucin coat thickens as the zygote passes down the oviduct. A proteinaceous shell is laid down outside the mucin coat in the utero-tubal region of the tract. The fertilized zygote enters the uterus in the pronuclear stage with cleavage proceeding in the uterus. In vivo, the first cleavage takes place two days post coitum (p.c.) (approximately 24 h after ovulation) but the next three cleavage stages may be completed within 24 h (between 48 h and 72 h p.c.). Thus, cell-doubling time appears to be around 8 h for 2-8-cell stages. Cleavage in vitro can occur with, or without, the shell membrane. Cleavage in early embryos of the tammar in vitro is slower than that occurring in vivo, and in vitro there may be a '4-cell block' in early development, as in dasyurids. The pattern of cleavage differs markedly from that of dasyurid marsupials in that there is no extrusion of yolk material from the cells and no separation of the blastomeres during the first cleavage stages to the 8-cell stage. The blastomeres are characterized by numerous vesicular structures and lipid droplets, but no yolk bodies. Polarity is not marked in early cleavage, but by the 8-cell stage polarity has developed with surface microvilli and numerous granular vesicles and mitochondria in the cortical regions at one pole of the cells, but sparse microvilli on the inner surfaces and at the other pole. There are complex intervillous interdigitations of microvilli between cells. However, clear identification of cells as pluriblast or trophoblast cells is not possible up to the 8-cell stage examined. These results demonstrate that this macropodid marsupial has a distinctive pattern of early development which differs from that of Didelphis and of the dasyurid marsupials so far described.
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Lewis AM, Su M, Doty J, Chen Y, Pardo FS. Relationship between intrinsic radiation sensitivity and metastatic potential. Int J Radiat Oncol Biol Phys 1996; 34:103-10. [PMID: 12118537 DOI: 10.1016/0360-3016(95)02008-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Prior studies emphasized genetic modulation of tumorigenicity, and experimental metastatic potential in cells transfected with oncogenes. Whether the intrinsic radiaton sensitivity of cells might correlate with parallel changes in metastatic potential is unknown. METHODS AND MATERIALS Rat embryo cells (REC) were transfected with the following oncogenes, and where appropriate, with corresponding selection markers: pCMVneopEJ6.6ras, pEJ6.6ras/v-myc, pEla, and pEJ6.6ras/Ela. Individual transfectant clones and corresponding pooled cellular populations were propagated in selective medium. In vitro cellular radiation sensitivity was determined via clonogenic assays, a minimum of three, by standard techniques and individual SF2 and MID parameters determined. Tumorigenicity was defined as the number of tumors forming following the injection of 1 x 10(5) - 1 x 10(6) cells into the axillary pouch of three different strains of immune-deficient mice. Animals were killed once resultant tumors reached a maximum size of 1.5-2.0 cm in maximum diameter. For determination of experimental metastatic potential, between 1 x 10(5) - 1 x 10(6) cells were injected into the tail veins of litter-matched sibling mice in parallel to the tumorigenicity studies. RESULTS Radiobiologic studies indicate similar levels of radiation sensitivity among REC, mock-transfected REC, Ela, and combined E1a/ras transfectants. pEJ6.6ras, and combined ras/myc transfected pooled cellular populations demonstrated increases in radiation resistance when compared to the pooled radiobiologic data from untransfected and mock-transfected corresponding pooled cellular populations (p <0.05, two-tailed test, SF2, MID). Rat embryo cells, Ela, and mock-transfectants were relatively radiation sensitive and nontumorigenic. pEla/ras was tumorigenic but demonstrated relatively low experimental metastatic potential. Ras, and ras/myc transfectants, demonstrated similar levels of experimental metastatic potential on lung colonization assays. CONCLUSIONS A good correlation exists between the intrinsic radiation sensitivity and the experimental metastatic potential of transfected REC. The highest levels of radiation resistance in vitro and experimental metastatic potential in vivo were found among REC transfected with ras/myc or activated ras alone. E1a/ ras cotransfected cellular populations, although tumorigenic, were relatively radiation sensitive and nonmetastatic. Further study is needed to formulate a mechanistic explanation for the intriguing correlation between intrinsic radiation sensitivity in vitro and metastatic potential in vivo.
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Lewis AM, Banks SM, Soddu S, Cook JL. The effects of end point overdispersions on the validity of single-dose tumorigenicity assays. Cancer Lett 1995; 93:179-86. [PMID: 7621426 DOI: 10.1016/0304-3835(95)03807-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Overdispersion can be found in tumor incidence and tumor latency end point values obtained by the conventional assays that are being used to assess the tumorigenicity of neoplastic cells growing in tissue culture. Failure to account for such wide variations in end point data can lead to incorrect assessments of the neoplastic cell tumorigenic phenotype and misinterpretations of data relating genetic functions to tumor-forming capacity. This problem suggests the need for more detailed analyses of the relationships that exist between tumor cell dose and the parameters being used to measure tumorigenicity.
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Lewis AM. Swedish cancer survey: one in three patients survive. BMJ (CLINICAL RESEARCH ED.) 1995; 310:617. [PMID: 7703741 DOI: 10.1136/bmj.310.6980.617a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Eyler YL, Siwarski DF, Huppi KE, Lewis AM. A p53 mutation in exon 5 associated with adenovirus transformation. Mol Carcinog 1995; 12:1-6. [PMID: 7818760 DOI: 10.1002/mc.2940120102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The adenovirus type 5 (Ad5) 55-kDa E1B oncoprotein has been shown to form complexes with the p53 tumor suppressor protein. These complexes are thought to interfere with normal p53 activity and may be responsible for the paucity of p53 mutations in cells transformed by these viruses. This report describes an example of a p53 mutation in exon 5 in an Ad5-transformed cell line that exhibited less expression of E1B 55-kDa protein and a longer tumor-latency phenotype than another Ad5-transformed cell line expressing wild-type p53. The finding of a p53 mutation in an Ad5-transformed cell line is unusual, especially considering the current theory that p53-E1B interactions play an important role in adenovirus transformation. This mutation could represent an alternative method of inactivating p53 function in the absence of sufficient levels of E1B 55-kDa oncoprotein.
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Lewis AM. Creative aesthetic treatment options: a case study. DENTISTRY TODAY 1994; 13:52, 54, 56-7. [PMID: 9540505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Boone K, Lewis AM, Holder DS. Imaging of cortical spreading depression by EIT: implications for localization of epileptic foci. Physiol Meas 1994; 15 Suppl 2a:A189-98. [PMID: 8087042 DOI: 10.1088/0967-3334/15/2a/024] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Severe epileptics may require curative neurosurgery. Sometimes focus localization requires recording with electrodes inserted deep into the brain, which may cause death or permanent neurological damage. Since epileptic seizures are associated with marked changes in cerebral impedance, we propose that EIT with sub-dural electrodes (inserted between the brain and skull) could provide a superior and less dangerous method for the localization of epileptic foci. The purpose of these experiments was to determine whether EIT could be used to localize the origin of seizure activity. In terms of impedance characteristics, an appropriate model is cortical spreading depression in the animal brain. Six rabbits were anaesthetized and paralysed and the brain exposed. EIT images and DC potentials were recorded from an array of 16 electrodes on the brain during cortical spreading depression induced by DC stimulus. Cortical spreading depression could be localized by EIT with an accuracy of 8.7% +/- 6.4% (mean +/- SD) of electrode array diameter. The errors in localization appeared to be distributed randomly. In a phantom of similar geometry, the error was 5% after correction for a systematic component. Results are sufficiently encouraging that we intend to extend this study to human patients.
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Lewis AM. Cosmetic consultation and treatment. DENTISTRY TODAY 1994; 13:72, 74, 76-7. [PMID: 9540606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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