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Walker C, Williams H, Phelan J. Allergic rhinitis history as a predictor of other future disqualifying otorhinolaryngological defects. AVIATION, SPACE, AND ENVIRONMENTAL MEDICINE 1998; 69:952-6. [PMID: 9773895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND Problems with the otorhinolaryngological system represent the largest category of pilot referrals for specialist assessment and possible waiver recommendation in the U.S. Navy. Most of these referrals deal with allergic rhinitis (AR). Approximately 3% of all Naval aircrew have a waiver for AR. This paper tests the hypothesis that the identification of a history of AR is a predictor for the development of future disqualifying otorhinolaryngological (ear, nose, and throat, or ENT) diseases such as chronic sinusitis, alternobaric disease, conductive hearing loss, or the need for various surgical procedures (i.e., Caldwell Luc antrostomy, myringotomy, polypectomy, mastoidectomy, and functional endoscopic sinus surgery. METHODS The U.S. Navy Aviation Medical Data Retrieval System (AMDRS) was searched for aircrew who were diagnosed only with AR in 1988. These aircrew were matched with a control group from the 1988 database who had no diagnoses of AR or any of the other disqualifying ENT diseases. The AR cohort and controls had their physical examinations up to 1995 assessed to see if any of the disqualifying ENT conditions had developed. RESULTS There was a statistically significant increase in the number of identifiable chronic sinusitis cases but there was no significant relationship between an AR history and the development of any of the other ENT disease categories. CONCLUSION Based on the study findings, it is doubtful that uncomplicated AR as an isolated historical diagnosis should be disqualifying for either candidate or designated aircrew.
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Walker C, Packiarajah P, Gilkerson JR, Love DN, Whalley JM. Primary and challenge infection of mice with equine herpesvirus 1, strain HSV25A. Virus Res 1998; 57:151-62. [PMID: 9870583 DOI: 10.1016/s0168-1702(98)00092-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Clinical signs, haematology, lymphocyte subset analysis, viral clearance, lung histopathology and humoral and cell-mediated (CMI) immune responses were monitored throughout the acute and convalescent phases of infection in groups of BALB/c mice infected intranasally with equine herpesvirus 1 (EHV-1), strain HSV25A. Primary infection caused a leucocytosis due to a neutrophilia during days 1 and 2 post-infection (pi) and a B lymphocytosis at day 1 pi. Serum ELISA antibodies were detected by 7 days pi and neutralising antibodies by 2 weeks pi. Mice infected with EHV-1 were not protected against disease when challenged with EHV-1 12 weeks later. However, viral clearance from lungs was significantly faster and the antibody response was markedly enhanced within the first few days of challenge infection. A CMI response was detected by 5 days after primary infection, but the level of responsiveness was not increased by challenge infection, although the lungs of challenged mice had markedly increased numbers of mononuclear cells around blood vessels and bronchioles. Specific antibodies to glycoprotein (g) B were detected by 2 weeks pi, 4 weeks earlier than the detection of antibodies to gC and 10 weeks before those to gD. The primary response was relatively short-lived with neither ELISA antibody nor lymphocyte proliferation was evident by 6 months pi.
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Kukreja A, Walker C, Fitzmaurice T, Awan A, Love DN, Whalley JM, Field HJ. Protective effects of equine herpesvirus-1 (EHV-1) glycoprotein B in a murine model of EHV-1-induced abortion. Vet Microbiol 1998; 62:303-11. [PMID: 9791876 DOI: 10.1016/s0378-1135(98)00211-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In an attempt to determine if pregnant mice could be protected from abortion subsequent to challenge with equine herpesvirus-1 (EHV-1) in the mouse model of EHV-1 disease, female BALB/c mice were inoculated with baculovirus-expressed EHV-1 glycoprotein B (bac-gB), wild-type baculovirus (bac-wt), rabbit kidney (RK-13) or baby hamster kidney (BHK-21) cells. Using an ELISA, antibodies against EHV-1 were detected in the serum of mice following two injections of bac-gB and were enhanced by a third injection, after which low levels of neutralising antibody were also detected. After mating, mice in the bac-gB, bac-wt and RK-immunised groups were infected intranasally with 10(7) pfu of EHV-1 on day 16 of pregnancy. All challenged mice experienced body weight loss post-infection (pi). However, postnatally, the gB-immunised group demonstrated body weight gain which was not seen in the other groups. There were no maternal deaths in the gB-immunised group but 1/6 bac-wt-immunised and 3/6 RK-immunised mice died post-challenge. Litter survival rate was significantly higher (p < 0.001) for the gB-immunised dams (54%) than that of either the bac-wt-(9%) or RK-immunised (0%) dams and the mean body weight of young from the surviving bac-wt-immunised litter was significantly (p = 0.021) lower than either the gB-immunised group or the BHK-immunised unchallenged group at 10 days of age. The virus was not isolated from any foetus from a gB-immunised dam. However, the virus was detected in 9% of foetuses from bac-wt-immunised and 21% of foetuses from RK-immunised dams.
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Walker C, Checkel J, Cammisuli S, Leibson PJ, Gleich GJ. IL-5 production by NK cells contributes to eosinophil infiltration in a mouse model of allergic inflammation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1998; 161:1962-9. [PMID: 9712067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
IL-5 production in vivo plays a unique role in the production, activation, and localization of eosinophils in a variety of allergic conditions. The current paradigm suggests that allergen-specific Th2 cells are the main source for the IL-5 production. The experiments outlined in this work, however, suggest that in vivo production of IL-5 by NK cells can separately influence eosinophil-associated inflammatory responses. Specifically, a mouse model of allergic inflammation was used in which C57BL/6 mice were immunized and challenged with a short ragweed Ag extract, known to induce a selective eosinophilia within the peritoneal cavity. Peritoneal lavage fluids from these mice also contained increased numbers of T cells and NK cells, as well as significantly elevated levels of IL-4, IL-5, and IFN-gamma. Flow-cytometric analysis of cytokine-producing cells in peritoneal lavage fluid revealed increased numbers of IL-5-producing cells in both T cell and NK cell populations following allergen exposure. Depletion of NK cells by treatment with NK1.1 Abs selectively reduced the number of infiltrating eosinophils by more than 50%. Moreover, the inhibition of the infiltration of eosinophils was accompanied by a complete loss of IL-5-producing NK cells and significantly reduced levels of peritoneal lavage fluid IL-5, whereas the number of IL-5-producing T cells was not affected. Thus, the results presented in this study provide clear evidence for a novel immunoregulatory function of NK cells in vivo, promoting allergen-induced eosinophilic inflammatory responses by the production of IL-5.
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Weaver CH, Zhen B, Schwartzberg L, Walker C, Upton S, Buckner CD. A randomized trial of mobilization of peripheral blood stem cells with cyclophosphamide, etoposide, and granulocyte colony-stimulating factor with or without cisplatin in patients with malignant lymphoma receiving high-dose chemotherapy. Am J Clin Oncol 1998; 21:408-12. [PMID: 9708644 DOI: 10.1097/00000421-199808000-00019] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to evaluate the addition of cisplatin to cyclophosphamide, etoposide, and granulocyte colony-stimulating factor (G-CSF) for the mobilization of peripheral blood stem cells (PBSC). Eighty-one patients with malignant lymphoma were randomized to receive either cyclophosphamide 4 g/m2 and etoposide 600 mg/m2 (CE), and G-CSF 6 microg/kg/day (n = 41), or the same drugs with cisplatin 105 mg/m2 (CEP; n = 40) followed by collection of PBSC. Seventy-eight of 81 patients (96%) had apheresis performed and 70 (86%) received high-dose chemotherapy (HDC) with PBSC support. The median number of CD34+ cells collected after CE was 19.77 compared with 9.39 x 10(6)/kg after CEP (p = 0.09). More patients receiving CEP had grade 3-4 gastrointestinal (p = 0.03) and neurologic toxicities (p = 0.05), had significant delays in recovery of neutrophils (p = 0.0001) and platelets (p = 0.009), and received more red blood cell (p = 0.03) and platelet (p = 0.08) transfusions than patients receiving CE. There were no significant differences in treatment-related deaths, relapse, survival, or event-free survival between patients receiving CE or CEP when all 81 patients or the 70 patients receiving HDC were evaluated. It was concluded that the addition of cisplatin to CE did not improve CD34+ cell yields, was associated with more morbidity and resource utilization, and was not associated with improvement in outcomes.
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306
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Rivetti C, Walker C, Bustamante C. Polymer chain statistics and conformational analysis of DNA molecules with bends or sections of different flexibility. J Mol Biol 1998; 280:41-59. [PMID: 9653030 DOI: 10.1006/jmbi.1998.1830] [Citation(s) in RCA: 218] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The worm-like chain model has often been employed to describe the average conformation of long, intrinsically straight polymer molecules, including DNA. The present study extends the applicability of the worm-like chain model to polymers containing bends or sections of different flexibility. Several cases have been explicitly considered: (i) polymers with a single bend; (ii) polymers with multiple coplanar bends; (iii) polymers with two non-coplanar bends; and (iv) polymers comprised of sections with different persistence lengths. Expressions describing the average conformation of such polymers in terms of the mean-square end-to-end distance have been derived for each case. For cases (i) and (iv), expressions for the projection of the end-to-end vector onto the initial orientation of the chain are presented. The expressions derived here have been used to investigate DNA molecules with sequence-induced bending (A-tracts). Mean-square end-to-end distance values determined from a large number of A-tract containing DNA molecules visualized by scanning force microscopy resulted in an average bend angle of 13.5 degrees per A-tract. A similar study was performed to characterize the flexibility of double-strandedDNA molecules containing a single-stranded region. Analysis of their mean-square end-to-end distance yielded a persistence length of 1.3 nm for single-stranded DNA.
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307
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Perry MJ, O'Connell J, Walker C, Crabbe T, Baldock D, Russell A, Lumb S, Huang Z, Howat D, Allen R, Merriman M, Walls J, Daniel T, Hughes B, Laliberte F, Higgs GA, Owens RJ. CDP840: a novel inhibitor of PDE-4. Cell Biochem Biophys 1998; 29:113-32. [PMID: 9631241 DOI: 10.1007/bf02737831] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We present the in vitro characterization of a novel phosphodiesterase type 4 inhibitor, CDP840 (R-[+]-4-[2-¿3-cyclopentyloxy-4-methoxyphenyl¿-2-phenylethyl]pyridine), which has shown efficacy in a phase II allergen challenge study in asthmatics without adverse effects. CDP840 potently inhibits PDE-4 isoenzymes (IC50 2-30 nM) without any effect on PDE-1, 2, 3, 5, and 7 (IC50 > 100 microM). It exhibited no significant selectivity in inhibiting human recombinant isoenzymes PDE-4A, B, C or D and was equally active against the isoenzymes lacking UCR1 (PDE-4B2 and PDE-4D2). In contrast to rolipram, CDP840 acted as a simple competitive inhibitor of all PDE-4 isoenzymes. Studies with rolipram indicated a heterogeneity within all the preparations of PDE-4 isoenzymes, indicative of rolipram inhibiting the catalytic activity of PDE-4 with both a low or high affinity. These observations were confirmed by the use of a PDE-4A variant, PDE-4A330-886, which rolipram inhibited with low affinity (IC50 = 1022 nM). CDP840 in contrast inhibited this PDE-4A variant with similar potency (IC50 = 3.9 nM), which was in good agreement with the Kd of 4.8 nM obtained from [3H]-CDP840 binding studies. Both CDP840 and rolipram inhibited the high-affinity binding of [3H]-rolipram binding to PDE-4A, B, C, and D with similar Kd app (7-19 nM and 3-5 nM, respectively). Thus, the activity of CDP840 at the [3H]-rolipram binding site was in agreement with the inhibitor's activity at the catalytic site. However, rolipram was approximately 100-fold more potent than CDP840 at inhibiting the binding of [3H]-rolipram to mouse brain in vivo. These data clearly demonstrate that CDP840 is a potent selective inhibitor of all PDE-4 isoenzymes. In contrast to rolipram, CDP840 was well-tolerated in humans. This difference, however, cannot at present be attributed to either isoenzyme selectivity or lack of activity in vitro at the high-affinity rolipram binding site (Sr).
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308
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Mickley GA, Schaldach MA, Snyder KJ, Balogh SA, Len T, Neimanis K, Goulis P, Hug J, Sauchak K, Remmers-Roeber DR, Walker C, Yamamoto BK. Ketamine blocks a conditioned taste aversion (CTA) in neonatal rats. Physiol Behav 1998; 64:381-90. [PMID: 9748108 DOI: 10.1016/s0031-9384(98)00097-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
These experiments explored the effects of glutamate, N-methyl-D-aspartate (NMDA) receptor blockade on the formation, retention, and expression of conditioned taste aversion (CTA) in young rats. Previous data from our laboratory suggested that ketamine administration potentiates a CTA in E18 rat fetuses. The current studies investigated this phenomenon in neonates. High-pressure liquid chromatography (HPLC) methods were used to determine the amount of ketamine that must be injected intraperitoneally (i.p.) to achieve brain ketamine levels in neonates comparable to those found in the fetuses from our previous experiments. Then, on their day of birth, Sprague-Dawley rat pups received injections of either 0.1, 10, or 70 mg/kg of ketamine HCI, i.p. or a Sal control injection. One-half hour later, pups were injected orally with either Saccharin (Sac; 10 microL of 0.3%) or water followed by an injection of either lithium chloride (LiCl; 81 mg/kg) or Sal (i.p.). The CTA was evaluated in two different tests. Two weeks after conditioning, the dam was anesthetized and the frequency with which pups attached to Sac-painted nipples versus nipples painted with water was measured (i.e., the nipple taste test, NTT). Controls for state-dependent learning were run in which 10 mg/kg of ketamine or saline (Sal) was administered before both taste aversion conditioning and the NTT. After weaning, the CTA was also evaluated by measuring the amount of Sac (0.3%) or water consumed during a two-bottle test. Neonates that received Sal control injections before the Sac + LiCl pairing acquired CTAs and avoided Sac-painted nipples. However, the pups injected with ketamine on the conditioning day only (P0) did not avoid Sac-painted nipples (as compared to controls). Pups that had ketamine both at the time of CTA training and testing, or just before the NTT, also failed to avoid Sac-painted nipples. Ketamine's acute effects apparently influenced the outcome of the NTT of state-dependent control subjects. Rat pups that received the highest doses of ketamine (10 or 70 mg/kg) and tasted Sac on P0 later failed to show a neophobia for Sac-painted nipples. Whereas, rat pups that received the high dose of ketamine and water on P0, later exhibited a neophobic response. These data suggest that ketamine did not impair the animal's ability to taste Sac. These data reflecting a ketamine-induced blockade of neonatal CTAs may be contrasted with our previous findings in which ketamine potentiated fetal CTAs. However, they are in consonance with data from adult rats suggesting that ketamine can cause an amnesia for CTAs. NMDA receptor blockade may shape memory formation in a manner that is dependent on the stage of brain development.
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309
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Walker C. What science is. IMAGE--THE JOURNAL OF NURSING SCHOLARSHIP 1998; 30:6-7. [PMID: 9549934 DOI: 10.1111/j.1547-5069.1998.tb01218.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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310
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Ren Y, Walker C, Ruan KH, Kulmacz RJ. Examination of prostaglandin H synthase-1 topology in the endoplasmic reticulum membrane. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1998; 400A:171-5. [PMID: 9547554 DOI: 10.1007/978-1-4615-5325-0_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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311
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Packiarajah P, Walker C, Gilkerson J, Whalley JM, Love DN. Immune responses and protective efficacy of recombinant baculovirus-expressed glycoproteins of equine herpesvirus 1 (EHV-1) gB, gC and gD alone or in combinations in BALB/c mice. Vet Microbiol 1998; 61:261-78. [PMID: 9646476 DOI: 10.1016/s0378-1135(98)00189-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Baculovirus-expressed glycoproteins of EHV-1 gB, gC and gD alone or in combination evoked antibody responses and protected vaccinated mice against a challenge with EHV-1. gB, gD, gB + gC, gB + gD and gC + gD elicited very high levels of ELISA antibodies while gC and gC + gD elicited high levels of virus neutralising antibodies. Western blotting demonstrated that the antibodies produced were not only specific for the baculovirus-expressed glycoproteins gB, gC and gD, but also highly specific for each EHV-1 glycoprotein. Vaccination of mice with gB or gD prevented clinical signs of infection in mice challenged with EHV-1 and all vaccinated groups of mice except controls showed a rapid clearance of virus from the lungs and a reduction in lesions characteristic of herpesviruses in the lungs post-challenge. Notably, the lungs of mice vaccinated with gB, gD or gB + gD and challenged with EHV-1 showed prominent peribronchiolar and perivascular aggregations of mononuclear cells, predominantly lymphocytes. Immunocytochemical staining of these sections showed large numbers of T cells, suggesting an active role for these cells at the site of virus replication post-challenge.
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312
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Walker C, Kaiser K, Klein W, Lagadic L, Peakall D, Sheffield S, Soldan T, Yasuno M. 13th Meeting of the Scientific Group on Methodologies for the Safety Evaluation of Chemicals (SGOMSEC): alternative testing methodologies for ecotoxicity. ENVIRONMENTAL HEALTH PERSPECTIVES 1998; 106 Suppl 2:441-51. [PMID: 9599690 PMCID: PMC1533412 DOI: 10.1289/ehp.98106441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
There is growing public pressure to minimize the use of vertebrates in ecotoxicity testing; therefore, effective alternatives to toxicity tests causing suffering are being sought. This report discusses alternatives and differs in some respects from the reports of the other three groups because the primary concern is with harmful effects of chemicals at the level of population and above rather than with harmful effects upon individuals. It is concluded that progress toward the objective of minimizing testing that causes suffering would be served by the following initiatives--a clearer definition of goals and strategies when undertaking testing procedures; development of alternative assays, including in vitro test systems, that are based on new technology; development of nondestructive assays for vertebrates (e.g., biomarkers) that do not cause suffering; selection of most appropriate species, strains, and developmental stages for testing procedures (but no additional species for basic testing); better integrated and more flexible testing procedures incorporating biomarker responses, ecophysiological concepts, and ecological end points (progress in this direction depends upon expert judgment). In general, testing procedures could be made more realistic, taking into account problems with mixtures, and with volatile or insoluble chemicals.
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313
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Woolley I, Valdez H, Walker C, Landay A, Zdunek D, Hess G, Lederman MM. High prevalence of hepatitis G virus RNA and antibody to probable viral envelope protein but not both in AIDS patients' plasma. AIDS 1998; 12:530-1. [PMID: 9543453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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314
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Walker C, Vierck CJ, Ritz LA. Balance in the cat: role of the tail and effects of sacrocaudal transection. Behav Brain Res 1998; 91:41-7. [PMID: 9578438 DOI: 10.1016/s0166-4328(97)00101-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To determine whether the tail of the domestic cat plays a role in balance during locomotion, four cats were trained to traverse a narrow beam. To challenge balancing ability, a sudden lateral displacement was imparted to the beam as the subject was crossing. Freeze-frame videotape analysis revealed that cats responded to beam movement by rapidly moving the tail in the opposite direction. Adjustment of the tail contributed to realignment of the hips over the beam and enabled the animal to remain aboard the beam. Following complete sacrocaudal spinal transection, that eliminated supraspinal control to only the tail, cats fell significantly more often in response to movements of the beam. The importance of the cat's tail for balance, and the utility of this system for modeling functional consequences of spinal cord injury and therapeutic interventions, are discussed.
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315
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Bridge JA, Roberts CA, Degenhardt J, Walker C, Lackner R, Linder J. Low-level chromosome 12 amplification in a primary lipoma of the lung: evidence for a pathogenetic relationship with common adipose tissue tumors. Arch Pathol Lab Med 1998; 122:187-90. [PMID: 9499365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cytogenetic analysis of a primary lipoma of the lung removed from a 56-year-old woman revealed the presence of a supernumerary marker chromosome in all metaphase cells analyzed; namely, 47,XX,+mar. To the best of our knowledge, this is the first cytogenetic description of a primary lipoma of lung. Genetic analysis of intramuscular lipoma, atypical lipoma, and well-differentiated liposarcoma have revealed the presence of one to three supernumerary ring or giant marker chromosomes composed of chromosome 12 segments as the characteristic anomaly. The marker chromosome in the present case was shown to be composed entirely of chromosome 12 material by subsequent analysis with a chromosome 12-specific paint probe and fluorescence in situ hybridization. Thus, analogous to intramuscular lipoma, atypical lipoma, and well-differentiated liposarcoma, extra chromosome 12 material is present. These findings support a pathogenetic relationship between this lipoma of unusual anatomic location and common adipose tissue tumors.
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316
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Shon KJ, Stocker M, Terlau H, Stühmer W, Jacobsen R, Walker C, Grilley M, Watkins M, Hillyard DR, Gray WR, Olivera BM. kappa-Conotoxin PVIIA is a peptide inhibiting the shaker K+ channel. J Biol Chem 1998; 273:33-8. [PMID: 9417043 DOI: 10.1074/jbc.273.1.33] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
kappa-Conotoxin PVIIA (kappa-PVIIA), a 27-amino acid toxin from Conus purpurascens venom that inhibits the Shaker potassium channel, was chemically synthesized in a biologically active form. The disulfide connectivity of the peptide was determined. kappa-Conotoxin PVIIA has the following structure. This is the first Conus peptide known to target K+ channels. [structure: see text] Although the Shaker K+ channel is sensitive to kappa-PVIIA, the rat brain Kv1.1 subtype is resistant. Chimeras between Shaker and the Kv1.1 K+ channels were constructed and expressed in Xenopus oocytes. Only channels containing the putative pore-forming region between the fifth and sixth transmembrane domains of Shaker retained toxin sensitivity, indicating that the toxin target site is in this region of the channel. Evidence is presented that kappa-PVIIA interacts with the external tetraethyl-ammonium binding site on the Shaker channel. Although both kappa-PVIIA and charybdotoxin inhibit the Shaker channel, they must interact differently. The F425G Shaker mutation increases charybdotoxin affinity by 3 orders of magnitude but abolishes kappa-PVIIA sensitivity. The precursor sequence of kappa-PVIIA was deduced from a cDNA clone, revealing a prepropeptide comprising 72 amino acids. The N-terminal region of the kappa-PVIIA prepropeptide exhibits striking homology to the omega-, muO-, and delta-conotoxins. Thus, at least four pharmacologically distinct superfamilies of Conus peptides belong to the same "O" superfamily, with the omega- and kappa-conotoxins forming one branch, and the delta- and muO-conotoxins forming a second major branch.
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317
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Condeluci A, Gooden-Ledbetter M, Walker C, Porro JM. Interdependence and life care planning. PEDIATRIC REHABILITATION 1998; 2:1-4. [PMID: 9661705 DOI: 10.3109/17518429809078609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Today's society is more litigant in accidental injury occurrences. With many injuries involving children, malpractice suits have resulted in an influx of information and rehabilitation supports. To address the growing need for legal representation in life care planning for injured persons, this easily understood tool provides the injured party with a viable approach to community interdependence and inclusion. Contrary to the conventionally medical model, where the person with a disability is viewed as needing 'fixed', this approach examines culture, community and the long term effects of disability. The individual with a disability is seen and understood within four aspects of personhood: capacities, gifts and passions; inclusive relationships; personal involvement; and understanding their culture and community. This life care planning process examines five eras in one's life cycle: formative/school age years, early work years, later work years, and retirement years. The specific needs of the individual in each life era are examined and specific costs itemized. The provision of adequate services and supports affords tremendous opportunities and inclusion into the community.
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318
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Talbot WS, Egan ES, Gates MA, Walker C, Ullmann B, Neuhauss SC, Kimmel CB, Postlethwait JH. Genetic analysis of chromosomal rearrangements in the cyclops region of the zebrafish genome. Genetics 1998; 148:373-80. [PMID: 9475747 PMCID: PMC1459804 DOI: 10.1093/genetics/148.1.373] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Genetic screens in zebrafish have provided mutations in hundreds of genes with essential functions in the developing embryo. To investigate the possible uses of chromosomal rearrangements in the analysis of these mutations, we genetically characterized three gamma-ray induced alleles of cyclops (cyc), a gene required for development of midline structures. We show that cyc maps near one end of Linkage Group 12 (LG 12) and that this region is involved in a reciprocal translocation with LG 2 in one gamma-ray induced mutation, cyc(b213). The translocated segments together cover approximately 5% of the genetic map, and we show that this rearrangement is useful for mapping cloned genes that reside in the affected chromosomal regions. The other two alleles, cyc(b16) and cyc(b229), have deletions in the distal region of LG 12. Interestingly, both of these mutations suppress recombination between genetic markers in LG 12, including markers at a distance from the deletion. This observation raises the possibility that these deletions affect a site required for meiotic recombination on the LG 12 chromosome. The cyc(b16) and cyc(b229) mutations may be useful for balancing other lethal mutations located in the distal region of LG 12. These results show that chromosomal rearrangements can provide useful resources for mapping and genetic analyses in zebrafish.
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319
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Flasse S, Walker C, Biggs H, Stephenson P, Hutchinson P. Using remote sensing to predict outbreaks of Oestrus ovis in Namibia. Prev Vet Med 1998; 33:31-8. [PMID: 9500162 DOI: 10.1016/s0167-5877(97)00056-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Directorate of Veterinary Services of the Ministry of Agriculture, Water and Rural Development of Namibia issues warnings to farmers in the south of the country about the likelihood of infestation of small-stock by the nasal bot fly, Oestrus ovis. Farmers can then treat their stock at the most appropriate time. The O. ovis puparia develop at shallow depths in the soil and the timing of emergence is directly dependent on climate conditions, specifically the number of degree-days above a particular threshold soil temperature. Based on temperature measurements from only a few stations scattered throughout the country, the veterinary department warnings lack precision in space and time. This paper presents an attempt to support the programme of warnings with accumulated temperature information from Meteosat satellite images, in order to strengthen predictions of the time of emergence in specific places, and to improve the precision and reliability of warnings given to farmers.
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320
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Abstract
Renal cell carcinoma (RCC) is the most common tumor of the adult kidney, accounting for approximately 85% of renal neoplasms. RCC is heterogeneous in appearance, displaying diverse histologic and cytologic characteristics, with the clear cell variant being the most common. Individuals at high risk for this disease include persons with end-stage renal disease, those with hereditary predispositions such as von Hippel-Lindau syndrome (VHL) or tuberous sclerosis (TSC), and individuals with significant environment exposures such as smoking or analgesic abuse. Recently, several of the genetic targets for alterations involved in the development of human RCC have been identified. Solid RCC of the clear cell type is associated with alterations in the VHL tumor suppressor gene and hereditary papillary RCC is associated with alterations of the c-met protooncogene. In the rat, the most commonly seen tumors are of the non-clear cell type and it is the Tsc-2 tumor suppressor gene, rather than the VHL tumor suppressor gene, that appears to be the primary target for both spontaneous and carcinogen-induced mutations in these animals. These data suggest that different variants of RCC have distinct molecular etiologies and that there are species-specific determinants that modulate the involvement of specific tumor suppressor genes in RCC. Interestingly, many of the genes involved in RCC also play significant roles in kidney development. The Wilm's tumor suppressor gene, WT-1, and Pax-2 regulate the mesenchymal epithelial transition that occurs during nephrogenesis and both these genes exhibit altered expression patterns and/or are mutated in renal tumors. Other genes such as c-met and its ligand hepatocyte growth factor are also involved in normal development and tumorigenesis, suggesting that tumors arise as a result of altered functions that are reflective of events that occur during nephrogenesis.
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321
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Walker C. Funding Melbourne's hospitals: some historical moments. AUST HEALTH REV 1997; 21:29-36. [PMID: 10181669 DOI: 10.1071/ah980029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In 1993 the Victorian Government introduced casemix funding as part of its restructure of the public hospital system. Casemix funding provides a new basis for government funding according to outcomes. At the same time, restructure of hospitals allows for a reconsideration of who is eligible to use them. Historical research into the growth of the public hospital system in Melbourne shows that attempts to reform the hospital system are as old as the system itself. This paper argues that the views of hospitals in funding crises and the solutions that are recommended have more to do with the politics of the day than the economics of running hospitals.
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322
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Walker C. NAFTA and occupational health: a Canadian perspective. North American Free Trade Agreement. J Public Health Policy 1997; 18:325-33. [PMID: 9360348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In Canada, health and safety laws are built around three worker rights which are not guaranteed by law in the United States: the right to participate in joint management-worker health and safety committees; the right to know about workplace hazards which requires consultation with the joint committee about the education and training programs; and the right to refuse hazardous work. In the context of NAFTA, health, safety and environmental laws and their enforcement, as well as the workers' compensation system, are all under attack by business leaders who cite the need to deregulate and privatize Canadian institutions in order to harmonize with the United States. The counteroffensive by the trade unions and their allies in the social justice movement is described; the struggle continues.
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323
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Fitzmaurice T, Walker C, Kukreja A, Sun Y, Brown SM, Field HJ. The pathogenesis of ED71, a defined deletion mutant of equine herpesvirus-1, in a murine intranasal infection model for equine abortion. J Gen Virol 1997; 78 ( Pt 9):2167-9. [PMID: 9292003 DOI: 10.1099/0022-1317-78-9-2167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A series of mutants of equine herpesvirus-1 (EHV-1) which contain deletions in non-essential genes was previously characterized in a murine intranasal infection model. One mutant, ED71 which was shown to be attenuated in the model, was further characterized by inoculation into pregnant mice. Despite the attenuation previously reported, intranasal inoculation of pregnant mice resulted in premature parturition and the birth of dead or dying foetuses. Furthermore, mice inoculated before pregnancy with the same mutant, and subsequently challenged 14 days after conception with wild-type virus, were not protected from abortion.
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324
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Heddle N, Kelton JG, Smaill F, Foss K, Everson J, Janzen C, Walker C, Jones M, Hammons D. A Canadian hospital-based HIV/hepatitis C look-back notification program. CMAJ 1997; 157:149-54. [PMID: 9238143 PMCID: PMC1227738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE To describe the process used to notify pediatric patients who received transfusions of blood or blood products at our institution before donor blood was routinely screened for antibodies to HIV (1985) and hepatitis C virus (1990), and to evaluate the effectiveness of the notification program. DESIGN Patients who had received transfusions were identified through the hospital's medical records and the records from the Transfusion Medicine Laboratory. Patients were contacted by registered mail to provide notification of transfusion. A questionnaire was included with the notification to obtain information about the patient's awareness of the transfusion and whether he or she had undergone or planned to undergo testing for HIV and hepatitis C virus. SETTING Tertiary care university-affiliated teaching hospital in Hamilton, Ont. PATIENTS Patients 16 years of age or younger who had received blood products between February 1978 and November 1985. Patients who had received only albumin or immune serum globulin were not included as these products were not associated with viral transmission in Canada. RESULTS Notification letters were sent to 1546 patients. Of these letters 522 (33.8%) were returned undelivered. Of the 1024 patients contacted 493 (48.1%) responded to the questionnaire, of whom 157 (31.8%) were not aware of their transfusion. A total of 130 (26.4%) of the respondents had already undergone testing for HIV, and 342 (69.4%) indicated that they would undergo such testing as a result of the notification. In contrast, only 30 (6.3%) of 474 respondents had undergone testing for hepatitis C virus, but 425 (89.7%) indicated that they would undergo such testing. Overall, the patients' response to the notification was neutral or positive; however, a number of patients expressed dissatisfaction and anxiety. CONCLUSIONS The high proportion of patients who were unaware that they had undergone transfusion and who decided to undergo testing for HIV and hepatitis C virus as a result of notification supports the use of notification programs such as this one.
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325
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Maland E, Walker C, Dalton J. Clinical Observations: Use of an EVA boot in a patient with a foot ulcer. J Wound Care 1997; 6:319-20. [PMID: 9325825 DOI: 10.12968/jowc.1997.6.7.319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study reports on the successful use of a protective boot in a patient with diabetic foot disease
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