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Turner AM, Bennett LG, Lin NL, Wypych J, Bartley TD, Hunt RW, Atkins HL, Langley KE, Parker V, Martin F. Identification and characterization of a soluble c-kit receptor produced by human hematopoietic cell lines. Blood 1995; 85:2052-8. [PMID: 7536489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Stem cell factor (SCF) triggers cell growth by binding to cell surface c-kit receptors. Soluble forms of several cytokine receptors have been described and may play a role in the modulation of cytokine activity in vivo. For these reasons, we investigated whether human hematopoietic cells produce soluble c-kit receptors. The human leukemia cell lines OCIM1 and MO7e display approximately 80,000 and approximately 35,000 high-affinity cell surface c-kit receptors, respectively. Soluble c-kit receptors were detected by enzyme immunoassay in OCIM1 and MO7e culture supernatants. We determined the molecular weight and binding affinity of soluble c-kit receptor produced by OCIM1 cells, soluble c-kit receptor purified from human serum, and recombinant soluble c-kit receptor expressed in CHO cells. The three soluble c-kit receptors each have a molecular weight of 98 kD. Quantitative binding experiments with 125I-SCF indicate that the soluble c-kit receptors obtained from human serum or OCIM1 cells have binding affinities for SCF of approximately 200 to 300 pmol/L, in contrast to the recombinant form, which has a binding affinity of approximately 1.5 nmol/L. All three forms of the soluble c-kit receptor were able to compete with c-kit receptors on OCIM1 cells for 125I-SCF binding. Thus human hematopoietic cells can produce a soluble form of the c-kit receptor that retains high-affinity SCF binding activity. We speculate that the soluble c-kit receptor may bind SCF and function as a receptor antagonist in vivo.
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Elliott S, Bartley T, Delorme E, Derby P, Hunt R, Lorenzini T, Parker V, Rohde MF, Stoney K. Structural requirements for addition of O-linked carbohydrate to recombinant erythropoietin. Biochemistry 1994; 33:11237-45. [PMID: 7727375 DOI: 10.1021/bi00203a020] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To define the structural requirements for addition of O-linked glycosylation in vivo, recombinant erythropoietin (rEPO) variants were constructed. Thirty-three independent Ser or Thr substitutions were constructed and examined to see which were subject to O-linked carbohydrate addition. Variants with Thr mutations at positions 123 and 125, but not elsewhere, contained additional carbohydrate, which suggests that several positions around the existing O-linked glycosylation site (Ser126), but not elsewhere, contain the necessary information for O-linked carbohydrate addition. Two forms of the Thr125 variant were identified. One form was glycosylated only at residue 125, and a second form was glycosylated at both Thr125 and Ser126, the normal O-glycosylation site. We have also found that glycosylation is less efficient when rEPO is improperly folded and that prolines at -1 and +1 relative to the O-glycosylation site enhance glycosylation.
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Morinan A, Parker V, Rich DA, Cariuk P, Horton RW. Social isolation does not alter brain regional benzodiazepine binding site numbers, affinity and coupling in the rat. Psychopharmacology (Berl) 1992; 106:565-9. [PMID: 1315974 DOI: 10.1007/bf02244831] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Male Sprague-Dawley rats were differentially housed for 21 days immediately after weaning. Isolated animals showed a selective suppression of exploration of the light side of a two compartment box; spending significantly less time in the light, and making fewer transitions between the light and dark compartments compared to socially reared controls. However, both basal and GABA-stimulated [3H] flunitrazepam binding was unaltered in the frontal cortex, hippocampus, amygdala and cerebellum following social isolation. These results are discussed in relation to other studies on central benzodiazepine receptor changes following a variety of experimental stressors.
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Parker V. Book Review. J Public Health (Oxf) 1990. [DOI: 10.1093/oxfordjournals.pubmed.a042536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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30
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Stanford SC, Parker V, Morinan A. Deficits in exploratory behaviour in socially isolated rats are not accompanied by changes in cerebral cortical adrenoceptor binding. J Affect Disord 1988; 15:175-80. [PMID: 2851619 DOI: 10.1016/0165-0327(88)90087-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Social isolation of rats produces marked deficits in exploratory behaviour in a novel environment. To test our hypothesis that adrenoceptors are modified by social isolation we have measured alpha 2- and beta-adrenoceptor binding in the cerebral cortex of rats isolated for 21 days starting immediately after weaning. After this period the animals showed a significant reduction in exploration in the elevated X-maze and increased avoidance of bright light in a two-compartment shuttlebox. There were no changes in adrenoceptor binding at this time, however. The implications of these findings are discussed.
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31
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Parker V. Legalizing drugs is humane and may work. THE JOURNAL OF THE FLORIDA MEDICAL ASSOCIATION 1988; 75:485. [PMID: 3171521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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32
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Wade DT, Parker V, Langton Hewer R. Memory disturbance after stroke: frequency and associated losses. INTERNATIONAL REHABILITATION MEDICINE 1986; 8:60-4. [PMID: 3804598 DOI: 10.3109/03790798609166175] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
138 patients who survived an acute stroke had their memory assessed at 3 months. As a group these patients had no impairment of digit span when compared with published age-matched normal data. Immediate logical memory (of a story) was poor in 29 per cent, and 14 per cent could not draw a picture immediately after seeing it. Poor memory function was not associated with more severe strokes, but was associated with poor functional ability on everyday tasks. Poor visual recall was associated with lower abilities at ADL, independent of any effect of age. Statistically significant recovery was detected in immediate logical memory and visual recall between 3 and 6 months.
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33
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34
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Parker V. Amnesia - towards a cure? Nursing 1984; 2:695-6. [PMID: 6563453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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35
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Mellon P, Parker V, Gluzman Y, Maniatis T. Identification of DNA sequences required for transcription of the human alpha 1-globin gene in a new SV40 host-vector system. Cell 1981; 27:279-88. [PMID: 6277501 DOI: 10.1016/0092-8674(81)90411-6] [Citation(s) in RCA: 550] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We have developed a rapid and simple method for studying the transcription of cloned eucaryotic genes, which involves transfecting SV40-transformed monkey cell lines (COS cells) with derivatives of the plasmid pBR322 that contain the SV40 viral replication origin but lack regions necessary for viral transcription (SV-ORI vectors). Because COS cells produce SV40 T antigen and are permissive for SV40 viral replication, transfected SV-ORI plasmids replicate to a high copy number. SV-ORI plasmids carrying a human alpha-globin gene are also replicated in COS cells. Moreover, the alpha-globin gene is faithfully transcribed to produce high levels of RNA, which is accurately processed to produce authentic alpha-globin mRNA. We have used this transcription system to demonstrate that a sequence located between 55 and 87 base pairs upstream from the mRNA capping site is required for efficient transcription of the alpha-globin gene in COS cells.
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36
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Parker V. Circulation vs. Photocopy. BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION 1981; 69:262. [PMID: 16017805 PMCID: PMC226803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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37
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Parker V. Casting light on Darwin's ape at Queen's University. CANADIAN MEDICAL ASSOCIATION JOURNAL 1980; 122:708-9. [PMID: 6988067 PMCID: PMC1801675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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38
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Robertson JS, Slattery JA, Parker V. Water sodium, hypertension and mortality. COMMUNITY MEDICINE 1979; 1:295-300. [PMID: 527313 DOI: 10.1007/bf02549242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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39
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Parker V. New library buildings: Bracken Library, Queen's University, Kingston, Ontario, Canada. BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION 1979; 67:387-93. [PMID: 486823 PMCID: PMC226956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A brief sketch is given of the past history and present functions of the Bracken Library. Architectural and decorative features of the new library are described.
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40
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Abstract
Over a thirty-year period in Scunthorpe, during which there were two changes in the sodium content of the water supply, there were significantly more sudden deaths in infancy during the decade when sodium levels were highest. This is compatible with the hypothesis that hypernatraemia is a factor leading to cot death. Changes in the incidence of breastfeeding over the same period may have contributed to, but are unlikely to account for, the result because the pattern was different in a neighbouring district where there was no change in water quality.
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Parker V. The relationship of medical school libraries to university library systems. BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION 1977; 65:451-3. [PMID: 901959 PMCID: PMC199399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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42
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Abstract
A method for the measurement of unconjugated testosterone and androstenedione in human urine is described. The method uses chromatographic separation followed by radioimmunoassay and has been examined for reliability. The mean 24-hour excretion of androstenedione by adult male subjects was 2.5 mug and of testosterone was 0.8 mug. For women, the mean excretion was 2.9 mug of androstenedione and 0.25 mug of testosterone. In pregnancy, androstenedione excretion was occasionally elevated above the normal range, but testosterone excretion was quite commonly increased. Some hirsute subjects exhibited an increase in androstenedione excretion, which was decreased by administration of dexamethasone. The results suggest that the amount of unconjugated testosterone in urine is not a direct reflection of the plasma free testosterone, but urinary androstenedione may be a useful reflection of plasma androstenedione levels.
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43
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Parker V, Bukhari AI. Genetic analysis of heterogeneous DNA circles formed after prophage Mu induction. J Virol 1976; 19:756-9. [PMID: 785026 PMCID: PMC354910 DOI: 10.1128/jvi.19.2.756-759.1976] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Induction of a Mu prophage in Escherichia coli Hfr strains lyosgenic for Mu cts62 leads to the generation of F' episomes. Each episome thus formed carries at least one copy of the Mu genome. These results suggest that integration of Mu is mandatory for the formation of the heterogeneous circles during the lytic cycle. The circles may be precursors for phage maturation.
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44
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Andino N, James VH, Parker V, Rippon AE. Proceedings; Excretion of urinary free androstenedione and testosterone. J Endocrinol 1976; 69:13P. [PMID: 950508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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45
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Parker V. The librarian and medical writing. BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION 1975; 63:225-6. [PMID: 1139065 PMCID: PMC198889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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46
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Parker V. Editorial: The big index for the small library. BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION 1974; 62:157. [PMID: 4826484 PMCID: PMC198778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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47
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Parker V. Watch your language. BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION 1973; 61:58. [PMID: 16017638 PMCID: PMC198609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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48
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Parker V. Comments on the possible involvement of disproportionation during anodic substitution reactions of 9,10-diphenylanthracene. J Electroanal Chem (Lausanne) 1972. [DOI: 10.1016/0368-1874(72)85070-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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49
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Parker V. Organizing a reprint file. BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION 1972; 60:149-51. [PMID: 5024325 PMCID: PMC198644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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50
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Parker V. The mechanism of anodic acetamidation. A comment on a paper by coleman, Richtol and Aikens. J Electroanal Chem (Lausanne) 1969. [DOI: 10.1016/0368-1874(69)80098-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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