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Walker DJ, Ottewell L, Moots RJ. To Do No Good. Rheumatology (Oxford) 2006. [DOI: 10.1093/rheumatology/kel385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Perahia DGS, Kajdasz DK, Walker DJ, Raskin J, Tylee A. Duloxetine 60 mg once daily in the treatment of milder major depressive disorder. Int J Clin Pract 2006; 60:613-20. [PMID: 16700869 PMCID: PMC1473178 DOI: 10.1111/j.1368-5031.2006.00956.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
There is ongoing debate regarding the effectiveness of antidepressants in patients with milder major depressive disorder (MDD). This post-hoc analysis evaluated the efficacy and tolerability of duloxetine in the subset of 159 (75 duloxetine and 84 placebo) patients with milder MDD (baseline HAMD17 total score > or = 15 and < or = 18) who were treated once daily with duloxetine 60 mg or placebo in two identical, 9-week, randomised, double-blind trials. At endpoint, change from baseline on HAMD17 was greater in the duloxetine group (-7.0) than in the placebo group (-4.1) (p = 0.005). Response and remission rates, and improvement on the Clinical Global Impressions-Severity (CGI-S) scale, the Patient Global Impressions-Improvement (PGI-I) scale, and measures of painful symptoms were also significantly better in the duloxetine group (p < 0.05). Tolerability was consistent with that seen in previous studies of duloxetine in patients with more severe depression. In conclusion, duloxetine 60 mg/day is effective and well tolerated in milder MDD.
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Walker DJ, Seidel Jr GE. 114 VITRIFICATION OF BOVINE EMBRYOS IN MEDIUM WITH POLYVINYL ALCOHOL REPLACING BSA. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Embryos vitrified in medium supplemented with 4.25 μg/mL sodium hyaluronate (SH) and 0.1% polyvinyl alcohol (PVA) survived vitrification better than embryos vitrified in medium supplemented with 0.25% FAF-BSA (Walker and Seidel 2005 Reprod. Fert. Dev. 17, 153). The purpose of the present study was to determine if the small amount of SH was beneficial to in vitro survival and to examine the effects of different concentrations of PVA in vitrification solutions. Day 7 blastocysts (n = 360) were produced in vitro with semen from three bulls, two replicates each. Cryoprotectant solutions were prepared in a 2 × 3 factorial combination with two SH concentrations (0 or 4.25 μg/mL) and three PVA concentrations (0.05, 0.1%, or 0.2%). For vitrification, embryos were placed into chemically defined HEPES-buffered medium (HCDM-2) at room temperature (22–24°C) and then transferred to V1 (5 m ethylene glycol in HCDM-2) for 3 min. Next, embryos were placed in a 6 μL drop of V2 (7 m ethylene glycol, 0.5 m galactose, and 18% w/v Ficoll 70 in HCDM-2) for 45 s. During these 45 s, dilution medium (0.5 m galactose in HCDM-2) was aspirated into 0.25-mL straws, followed by the 6 μL drop of V2 plus embryos and a final short column of dilution medium. When 45 s had elapsed, the heat-sealed end of straw was dipped into liquid nitrogen to cover the embryo, and then the remainder of the straw was immersed slowly. Straws were thawed in air for 10 s and then in 37°C water for 20 s. Next, straws were shaken like a clinical thermometer four times to mix columns, and held in 37°C water for 10 min before embryos were expelled, rinsed and cultured in CDM-2 + 5% FCS. At 48 h, embryo survival (as determined by expansion of blastocysts), embryo quality (1 = excellent, 2 = fair, 3 = poor), inner cell mass (ICM) quality (1 = large and compact, 2 = clearly visible, 3 = not discernable) and blastocyst stage (5 = early, 6 = full, 7 = expanded, 8 = hatching, 9 = hatched) were evaluated and replicate averages were analyzed by ANOVA. Neither bull nor SH concentration nor PVA concentration significantly affected any response (P > 0.10). Averaged over PVA concentrations, vitrification of embryos in 0 μg/mL or 4.25 μg/mL SH resulted in similar survival rates (67% vs. 62%, respectively). When averaged over SH concentrations, 0.2% PVA had a numerically higher survival rate of blastocysts as compared to 0.1% or 0.05% (71% vs. 63% and 60%, respectively). The main effects of 0 μg/mL SH and 0.2% PVA also resulted in numerically higher, but nonsignificant improvements in quality score, ICM score and blastocyst stage as compared to the other doses of SH and PVA. Vitrification of Day 7 in vitro-produced bovine blastocysts in medium containing 0.2% PVA in the absence of SH resulted in a subclass mean of 80% embryo survival. Results of this experiment show no benefit of 4.25 μg/mL SH and that 0.2% PVA may be slightly better than 0.05% or 0.1% in terms of embryo survival. Therefore, our results indicate that 0.2% PVA can be used alone as an effective alternative to animal products in this vitrification procedure for in vitro-derived bovine blastocysts.
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Campos-Chillòn LF, Walker DJ, de la Torre-Sanchez JF, Seidel GE. In vitro assessment of a direct transfer vitrification procedure for bovine embryos. Theriogenology 2005; 65:1200-14. [PMID: 16169072 DOI: 10.1016/j.theriogenology.2005.07.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Accepted: 07/10/2005] [Indexed: 11/29/2022]
Abstract
We developed a simple vitrification technique for bovine embryos that could permit direct transfer. Embryos were produced in-vitro by standard procedures. The base medium for cryopreservation was a chemically defined medium similar to SOF + 25 mM Hepes and 0.25% fatty acid free bovine serum albumin (FAF-BSA) (HCDM2). In experiment 1, embryos were first exposed to 3.5M ethylene glycol (V1) for 1, 2 or 3 min at room temperature (20-24 degrees C), and then moved to 7 M ethylene glycol (V2) at 4 or 20-24 degrees C and loaded in 0.25-mL straws. After 45 s in 7 M ethylene glycol, straws were placed in liquid nitrogen. Embryos that were loaded at 20-24 degrees C had higher survival rates than those loaded at 4 degrees C (P<0.05). Exposure for 1 min was best for morulae, while 3 min was best for blastocysts. In experiment 2, blastocysts were handled at 24 degrees C and exposed to two concentrations of ethylene glycol in V1 (3.5 or 5 M) followed by V2 as in experiment 1, two warming temperatures (20 or 37 degrees C) and two post-warming holding times until culture (5 or 15 min). Exposure to 5 M ethylene glycol and warming at 37 degrees C was the optimal combination of procedures, and embryos survived well after 15 min in straws if warmed at 37 degrees C. In experiment 3, ethylene glycol concentration (3, 4 or 5 M) and exposure time (0.5 or 1 min) during two-step addition of cryoprotectant were studied for bovine morulae. In experiment 4, morulae were exposed to V2 for 30 or 45 s in HCDM2 or Vigro holding medium and then held in 22-24 degrees C air or 37 degrees C water post-warming. Experiment 5 was like experiment 4 except blastocysts were used. Overall survival rates of blastocysts in experiment 5 averaged 80% of non-vitrified controls after 48 h culture. The survival rates with in vitro-produced morulae in experiments 1, 3 and 4 were unacceptable. Vitrification solutions based on Vigro tended to result in higher survival than HCDM2 for blastocysts, but not morulae. In experiment 6, the survival rate in vitro of in vivo-produced morulae and blastocysts after two-step vitrification was nearly 100%. Our vitrification technique was very effective for in vitro produced blastocysts, but not for in vitro-produced morulae.
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Myers A, Kay LJ, Lynch SA, Walker DJ. Recurrence risk for psoriasis and psoriatic arthritis within sibships. Rheumatology (Oxford) 2005; 44:773-6. [PMID: 15757963 DOI: 10.1093/rheumatology/keh589] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To quantify the frequency of siblings of patients with psoriatic arthritis (PsA) having psoriasis and/or inflammatory arthritis. To describe the similarity or otherwise of patterns of arthritis in siblings. METHODS Available and consenting index cases with PsA and one or more siblings living locally were assessed. Mean sibling concordance rates and Weinberg's segregation analysis were calculated. Heritability was also estimated. To assess whether the same type of arthritis occurred within the same sibship, the dually affected sibships were then classified for type of arthritis according to methods suggested by Moll, Helliwell, Veale and McGonagle. RESULTS Eighty index cases and 112 siblings were assessed. The median age of index cases was 49 yr (range 24-80 yr) and for siblings 46 yr (range 18-79 yr). The concordance rate for all types of PsA was 14% (9% if enthesitis is excluded) and for psoriasis 21%. There was no difference in the two methods used to calculate concordance rates. Sixteen dually affected sib pairs were found. Four of the 16 sibships (25%) had the same pattern of joint involvement (Moll and Wright classification). The most frequent pattern seen was joint involvement identical to rheumatoid arthritis (3/5). The most common symptom in affected siblings was enthesitis (approximately 5%). When the dually affected sibships were analysed using the other classifications, the simpler the classification the greater the concordance for joint pattern. CONCLUSION The concordance for psoriasis is greater than for PsA, but the concordance rate for PsA was similar to that in HLA identical siblings with rheumatoid arthritis. There was discordance in pattern of arthritis for most sib pairs. There is no support for the use of more complex classifications of PsA.
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Walker DJ. Is this the end of part-time clinical research? Rheumatology (Oxford) 2004. [DOI: 10.1093/rheumatology/keh159] [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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Carson CC, Rajfer J, Eardley I, Carrier S, Denne JS, Walker DJ, Shen W, Cordell WH. The efficacy and safety of tadalafil: an update. BJU Int 2004; 93:1276-81. [PMID: 15180622 DOI: 10.1111/j.1464-410x.2004.04819.x] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To provide an update on the efficacy and safety of tadalafil, a phosphodiesterase-5 inhibitor, in the treatment of erectile dysfunction (ED). PATIENTS AND METHODS In all, 2102 men (mean age 56 years) with mild-to-severe ED of various causes were randomized to placebo or tadalafil, taken as needed with no food restrictions, at fixed 'on-demand' doses of 10 or 20 mg in 11 randomized, double-blind, placebo-controlled trials lasting 12 weeks. The three co-primary outcomes were changes from baseline in the erectile function domain of the International Index of Erectile Function (IIEF) and the proportion of 'yes' responses to questions 2 and 3 of the Sexual Encounter Profile (SEP). Additional efficacy instruments included a Global Assessment Question (GAQ). RESULTS Compared with placebo, tadalafil gave significantly better outcomes. Patients receiving either dose of tadalafil had a significant mean improvement of 6.5 and 8.6, respectively, in the IIEF erectile function domain score from baseline (P < 0.001 vs placebo). At both doses the mean success rate for intercourse attempts (SEP-Q3) was 58% and 68%, respectively, compared with 31% in the placebo group (P < 0.001), and 71% and 84% reported improved erections at the endpoint (GAQ), vs 33% on placebo (P < 0.001). Tadalafil was effective up to 36 h after dosing and was effective regardless of disease severity and causes, and in patients of all ages. The most frequent adverse events were headache, dyspepsia, back pain and myalgia. CONCLUSION Tadalafil was an effective and well-tolerated treatment for ED.
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Walker DJ. Is this the end of clinical research? Rheumatology (Oxford) 2004; 43:806-7. [PMID: 15206419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
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Myers A, Lakey R, Cawston TE, Kay LJ, Walker DJ. Serum MMP-1 and TIMP-1 levels are increased in patients with psoriatic arthritis and their siblings. Rheumatology (Oxford) 2003; 43:272-6. [PMID: 14523226 DOI: 10.1093/rheumatology/keh032] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVE To determine matrix metalloproteinase-1 (MMP-1) and tissue-inhibitor metalloproteinase-1 (TIMP-1) serum levels in patients with psoriatic arthritis (PsA) and to compare this with their siblings and local blood donor controls. PsA is an interesting condition in which to study metalloproteinases because there are variations in the level of destructiveness, including a significant proportion of cases without destructive change. This is unlike rheumatoid arthritis (RA) which is more uniformly destructive and where MMP-1/TIMP-1 levels are known to be elevated. METHODS MMP-1 and TIMP-1 serum levels were determined by enzyme-linked immunosorbent assay (ELISA) in (a) index cases with PsA (subtype: RA n = 43, distal interphalangeal disease n = 2, oligoarticular n = 15, spondyloarthropathy n = 9, enthesitis n = 1), (b) siblings with PsA, (c) siblings with psoriasis (Ps), (d) unaffected siblings and (e) local controls. Patients with Ps were divided according to the onset of disease: type I disease, onset before age 40 yr and type II, onset after age 40 yr. RESULTS MMP-1 and TIMP-1 levels were significantly increased in both the index cases and the group including all siblings compared with the controls (P < 0.0001). There was no statistical difference in MMP-1 or TIMP-1 levels between index cases and their siblings. There was no difference in serum MMP-1 level between the different subtypes (Moll and Wright) of PsA, but there was an increased level of serum TIMP-1 in patients with rheumatoid pattern (P = 0.05). In the index cases there were increased levels of TIMP-1 in type II onset psoriasis (P = 0.03) but no difference in MMP-1 levels. CONCLUSION MMP-1 and TIMP-1 serum levels are elevated in PsA. This is greatest in RA pattern PsA. These levels were also elevated in unaffected siblings suggesting that genetic factors may be important. TIMP-1 levels were elevated in psoriasis alone, more so in late onset psoriasis, suggesting that the pathological processes of early and late onset psoriasis may be different.
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Foxon CT, Novikov SV, Belyaev AE, Zhao LX, Makarovsky O, Walker DJ, Eaves L, Dykeman RI, Danylyuk SV, Vitusevich SA, Kappers MJ, Barnard JS, Humphreys CJ. Current–voltage instabilities in GaN/AlGaN resonant tunnelling structures. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/pssc.200303376] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Walker DJ, Kay LJ. Musculoskeletal examination for medical students: the need to agree what we teach. Rheumatology (Oxford) 2002; 41:1221-3. [PMID: 12421993 DOI: 10.1093/rheumatology/41.11.1221] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Walker DJ, Heslop PS, Chandler C, Pinder IM. Measured ambulation and self-reported health status following total joint replacement for the osteoarthritic knee. Rheumatology (Oxford) 2002; 41:755-8. [PMID: 12096224 DOI: 10.1093/rheumatology/41.7.755] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE To quantify the increase in ambulation produced by total knee replacement for osteoarthritis (OA) of the knee and to compare this with questionnaire-derived data. METHODS We compared the measured ambulatory activity and self-reported Nottingham Health Profile (NHP) data of 19 subjects with OA of the knee before and after total knee replacement (TKR). RESULTS Subjects were considerably restricted in their measured activity before operation compared with subjects with less severe disease. At 6 months the activity had increased by an average of 79% (P=0.02). The pain scale of the NHP had significantly improved at 3 months, as had the mobility scale. Between 3 and 6 months, however, at the same time the measured activity was increasing, self-reported mobility declined. CONCLUSIONS Replacement of a knee for OA is an effective way of improving ambulation. At 6 months the average increase amounted to 79%. Self-reported mobility did not correlate with mobility measured objectively.
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Walker DJ, Zacny JP. Lack of effects of ethanol pretreatment on the abuse liability of nitrous oxide in light and moderate drinkers. Addiction 2001; 96:1839-45. [PMID: 11784476 DOI: 10.1046/j.1360-0443.2001.9612183913.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To determine effects of ethanol-use history and ethanol pretreatment on abuse liability of nitrous oxide (N(2)O). DESIGN Placebo-controlled, double-blind, cross-over design evaluating effects of N(2)O, 0% (100% O(2), placebo) and 30% (in O(2)), in the presence of three doses of ethanol: 0 g/kg (placebo), 0.35 g/kg and 0.7 g/kg. SETTING Subjects sat in a reclining chair in a hospital laboratory. PARTICIPANTS Eight healthy light drinkers (one drink or less/week) and eight healthy moderate drinkers (seven or more drinks/week) with no history of drug dependence completed the study. INTERVENTION On three sessions (1, 3, 5) subjects drank a beverage that contained one of the three ethanol doses, then sampled for 10 minute each 0% and 30% N(2)O. During choice sessions (2, 4, 6), subjects received the same ethanol dose as in the previous session, then chose six times, once every 5 min, between 0% and 30% N(2)O. MEASUREMENTS Subjective (self-reported) drug effects, reinforcing effects of N(2)O as assessed by choice, and psychomotor effects were measured. FINDINGS Choice of N(2)O did not differ between light (mean = 3.4 choices) and moderate (mean = 3.2 choices) drinkers and was not influenced by ethanol dose (0 g/kg: 3.3 choices, 0.35 g/kg: 3.5 choices, 0.7 g/kg: 3.1 choices). Subjective effects of N(2)O also did not depend on ethanol-use history or ethanol dose. N(2)O liking and desire to inhale the drug again were positively correlated with N(2)O choice. CONCLUSIONS Ethanol pretreatment and ethanol-use history had no effect on the abuse liability of N(2)O as assessed in the present study.
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Kay LJ, Coady DA, Walker DJ. Joints: if relevant. Do available textbooks contain adequate information about musculoskeletal examination skills for medical students? MEDICAL TEACHER 2001; 23:585-590. [PMID: 12098480 DOI: 10.1080/014215901200901032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The objective was to determine whether routinely available textbooks describe the core musculoskeletal examination skills for medical students. Textbooks were evaluated for content against a list of 27 core examination skills as perceived by rheumatologists, orthopaedic surgeons and general practitioners. The study took place in Newcastle upon Tyne, libraries of the rheumatology department, teaching hospital and medical school. The main outcome was the inclusion of a description of examination skills by available textbooks. Median score for each textbook was only 19 (range 1-24) of a possible 27 core skills. Screening examination was not included in general texts. General principles were well covered but detail was insufficient, particularly in texts aimed at students taking final examinations. It is not easy for students to access adequate information about core items of musculoskeletal examination from textbooks readily available to them. This may reflect a general view of the lack of importance of musculoskeletal clinical examination skills.
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Walker DJ, Zacny JP. Within- and between-subject variability in the reinforcing and subjective effects of nitrous oxide in healthy volunteers. Drug Alcohol Depend 2001; 64:85-96. [PMID: 11470344 DOI: 10.1016/s0376-8716(00)00234-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Within- and between-subject variability in the reinforcing and subjective effects of nitrous oxide (N(2)O) was studied across five sessions. Twelve volunteers with no history of drug dependence sampled 30% N(2)O and 100% oxygen for 10 min each, then chose nine times, once every 5 min, among N(2)O (e.g. "Agent A"), oxygen (e.g. "Agent B"), or "drug-free air." Choice varied across subjects but was stable within subjects. Quantitative differences in subjective effects occurred within and across subjects. Some subjective effects were correlated with choice and/or differed between subjects who were consistent choosers of N(2)O versus those who were not. However, drug liking and euphoria, two face-valid measures of abuse liability, were unrelated to choice. Thus, the present study found individual differences (i.e. between-subject variability) in subjective and reinforcing effects of N(2)O and, in terms of within-subject variability, suggested that subjective effects fluctuate across sessions to a relatively greater extent than do reinforcing effects. The varying degrees of correlation between N(2)O choice and its subjective effects emphasize the need for obtaining multiple measures when characterizing abuse liability of this drug.
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Walker DJ, Heslop PS, Chandler C, Cleary R. Extraction and validation of a lower limb HAQ by comparison with objective measurement of ambulatory activity. Scand J Rheumatol 2001; 30:154-8. [PMID: 11469525 DOI: 10.1080/030097401300162923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
OBJECTIVES Both the Health Assessment Questionnaire (HAQ) and the measurement of spontaneous ambulatory activity are measures that can be used to evaluate disability in RA. METHODS A cross sectional survey was conducted of 105 RA patients where the HAQ was compared with ambulatory activity from the Numact monitor. Rank correlation was used to evaluate the relationships between activity and the complete and individual sections of the HAQ. RESULTS Correlation of activity with total HAQ produced significant results (r= -0.29 to -0.48). Correlation with individual sections showed the strongest association with "Hygiene", followed by "Activities", and "Walking". A lower limb HAQ was devised using these and the dressing and rising items. CONCLUSIONS HAQ and recorded activity measure different but related aspects of disability. Activity should be used if the ability to quantify the result outweighs the extra effort involved in the study.
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Walker DJ, Zacny JP, Galva KE, Lichtor JL. Subjective, psychomotor, and physiological effects of cumulative doses of mixed-action opioids in healthy volunteers. Psychopharmacology (Berl) 2001; 155:362-71. [PMID: 11441425 DOI: 10.1007/s002130100723] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
RATIONALE Conducting complete dose-response evaluations of multiple drugs in a single within-subjects experiment is very time-consuming when a complete session is required for evaluation of each dose. OBJECTIVE To evaluate a within-session cumulative-dosing procedure as a potentially efficient method for conducting dose-response evaluations of mixed-action opioids. METHODS Fifteen healthy volunteers received intravenous injections of saline, butorphanol, nalbuphine, pentazocine, or morphine in a randomized, double-blind, crossover design. Subjects received one injection per hour for the first 4 h, and a 3-h recovery period followed. Saline was injected first, then saline or increasing doses of each drug (except pentazocine, see below) were administered every hour for the next 3 h. The absolute doses per injection were morphine and nalbuphine 2.5, 5, and 10 mg/70 kg, butorphanol 0.5, 1, and 2 mg/70 kg, and pentazocine 7.5, 15, and 0 mg/70 kg. (The highest dose of pentazocine was omitted because of the risk of dysphoria and psychotomimesis). These injections resulted in cumulative doses of morphine or nalbuphine 2.5, 7.5, and 17.5 mg/70 kg, butorphanol 0.5, 1.5, and 3.5 mg/70 kg, and pentazocine 7.5 and 22.5 mg/70 kg. Mood, psychomotor performance, and vital signs were assessed. RESULTS Effects of all opioids were similar, with some exceptions. Butorphanol had the strongest effects on psychomotor performance and some subjective effects. Morphine was associated with delayed or prolonged side effects. CONCLUSIONS Orderly dose-response functions and replication of results of single-dosing studies confirmed that the cumulative-dosing procedure is an efficient way of determining dose-response functions for multiple opioids within the same subjects.
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Jones B, Basson BR, Walker DJ, Crawford AM, Kinon BJ. Weight change and atypical antipsychotic treatment in patients with schizophrenia. J Clin Psychiatry 2001; 62 Suppl 2:41-4. [PMID: 11232752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Schizophrenic patients who have been prescribed atypical antipsychotics have a potential risk of gaining weight. The implications of weight gain for clinical care may differ depending on whether a patient is underweight or overweight at baseline. The exact mechanism for weight gain is not known, but several factors have been identified that can help predict which patients are at risk for gaining weight. These factors include better clinical outcome, increased appetite, and low baseline body mass index. In patients treated with olanzapine for up to 3 years, weight gain trended toward a plateau at approximately 36 weeks. Weight gain interventions, including behavioral modifications, show promise in controlling or reducing weight in patients treated with antipsychotics.
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Walker DJ. Modelling sedimentation processes in a constructed stormwater wetland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2001; 266:61-68. [PMID: 11258834 DOI: 10.1016/s0048-9697(00)00730-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The design and operation of constructed wetlands for the treatment of stormwater relies heavily on promoting sedimentation, and being able to predict accurately the expected effectiveness of the pond in removing material from the inflows. A study of sediment behaviour has been carried out in a stormwater wetland in Adelaide, Australia where computer predictions, based on solving the hydrodynamic equations and the transport equation, have been compared to deposition patterns observed in the field. The long-term residence time distribution has been shown to be useful in predicting overall sediment removal rates. Comparisons between the model and field observations indicate generally good agreement. Sources of potential error identified include the variable nature of the runoff concentrations entering the pond and the sediment size distribution. The importance of the transient nature of the flow events was highlighted by the spread of sediment throughout the whole pond.
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Kay LJ, Deighton CM, Walker DJ, Hay EM. Undergraduate rheumatology teaching in the UK: a survey of current practice and changes since 1990. Arthritis Research Campaign Undergraduate Working Party of the ARC Education Sub-committee. Rheumatology (Oxford) 2000; 39:800-3. [PMID: 10908701 DOI: 10.1093/rheumatology/39.7.800] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Walker DJ, Pitsch JL, Peng MM, Robinson BL, Peters W, Bhisutthibhan J, Meshnick SR. Mechanisms of artemisinin resistance in the rodent malaria pathogen Plasmodium yoelii. Antimicrob Agents Chemother 2000; 44:344-7. [PMID: 10639360 PMCID: PMC89681 DOI: 10.1128/aac.44.2.344-347.2000] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Artemisinin and its derivatives are important new antimalarials which are now used widely in Southeast Asia. Clinically relevant artemisinin resistance has not yet been reported but is likely to occur. In order to understand how the malaria parasite might become resistant to this drug, we studied artemisinin resistance in the murine malaria parasite Plasmodium yoelii. The artemisinin-resistant strain (ART), which is approximately fourfold less sensitive to artemisinin than the sensitive NS strain, accumulated 43% less radiolabeled drug in vitro (P < 0.01). Within the parasite, the drug appeared to react with the same parasite proteins in both strains. The translationally controlled tumor protein, one of the artemisinin target proteins, did not differ between the strains. No DNA sequence difference was found, but the resistant strain was found to express 2.5-fold-more protein than the sensitive strain (P < 0.01). Thus, the phenotype of artemisinin resistance in P. yoelii appears to be multifactorial.
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Walker DJ, Kidd E, Heslop PS, Chandler C. Spontaneous ambulatory activity as a quantifiable outcome measure for rheumatoid arthritis. Rheumatology (Oxford) 1999; 38:1234-8. [PMID: 10587551 DOI: 10.1093/rheumatology/38.12.1234] [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: 11/13/2022] Open
Abstract
OBJECTIVE To validate the objective monitoring of ambulatory activity as an outcome measure for rheumatoid arthritis (RA). METHODS We have compared ambulatory activity to a range of currently favoured outcome measures, ranging from subjective opinions to X-ray damage, in a population of 93 RA sufferers. RESULTS Correlations were stronger with measures of joint damage and disability, and less strong with measures of disease activity. Sensitivity to change was good. Three different interventions were compared for the quantity of the response, and the results agree with clinical experience, with steroid injection of the knee and use of non-steroidal anti-inflammatory drugs (NSAIDs) having a similar response and the provision of surgical shoes producing a more modest increase in ambulation. CONCLUSION The measurement of ambulatory activity has validity for RA assessment. It provides different but related data to the currently used measures. It is objective, relevant, quantifiable and of unlimited scale. It could be used to quantify interventions aimed at increasing ambulation, in carefully constructed studies.
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Walker DJ. Venous stasis wounds. Orthop Nurs 1999; 18:65-74, 95. [PMID: 11052053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Lower extremity wounds related to venous insufficiency are increasing. As the number of adults over the age of 65 increases, so do wounds related to changes in the vascular system. Venous stasis wounds can present as a real challenge to experienced practitioners. This article describes the many factors associated with venous wounds as well as the need for a comprehensive treatment plan.
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Bali D, Gourley S, Kostyu DD, Goel N, Bruce I, Bell A, Walker DJ, Tran K, Zhu DK, Costello TJ, Amos CI, Seldin MF. Genetic analysis of multiplex rheumatoid arthritis families. Genes Immun 1999; 1:28-36. [PMID: 11197302 DOI: 10.1038/sj.gene.6363635] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To examine the genetic contribution of HLA and non-HLA genes in the etiopathogenesis of rheumatoid arthritis (RA), 60 Caucasian multiplex families were identified and DNA analyzed for over 52 markers including DRB1, DQA1 and DQB1 alleles. Many of the markers were chosen because of close proximity to candidate genes suggested by previous studies or models of pathogenesis. Sibling pair analysis (SIBPAL), relative pair analysis (RELPAL) and linkage studies using two different models of inheritance suggested linkage for the MHC and two additional chromosomal regions: chromosome 2 (D2S443 near CD8 and IGk; 2p13-2p11.1), and chromosome 15 (CYP19-estrogen synthase; 15q15). No support was found for two chromosomal regions, 1p36 and 3q13, recently suggested by other studies. We used transmission disequilibrium testing (TDT), conditional logistic regression, and segregation analysis to study the contributions that the shared epitope and TNF-c have in contributing to risk for RA. These studies provide additional evidence that the association of HLA alleles in RA patients from multiplex families is similar to that observed in sporadic disease, suggest candidate regions for further analysis and find additional support for an association of TNF-c alleles with RA susceptibility.
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