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Morris CG, Low J. Metabolic acidosis in the critically ill: Part 1. Classification and pathophysiology. Anaesthesia 2008; 63:294-301. [DOI: 10.1111/j.1365-2044.2007.05370.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Favaloro EJ, Bonar R, Duncan E, Earl G, Low J, Aboud M, Just S, Sioufi J, Street A, Marsden K. Mis-identification of factor inhibitors by diagnostic haemostasis laboratories: recognition of pitfalls and elucidation of strategies. A follow up to a large multicentre evaluation. Pathology 2007; 39:504-11. [PMID: 17886101 DOI: 10.1080/00313020701569998] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AIMS We previously reported the ability of diagnostic haemostasis facilities to identify coagulation factor abnormalities and inhibitors, through a large multi-centre study conducted on behalf of the Royal College of Pathologists of Australasia (RCPA) Quality Assurance Program (QAP). In the current report, additional data evaluation aims to (1) help identify the reasons behind the failures in inhibitor identification, (2) highlight the pitfalls in inhibitor testing, and (3) help elucidate some strategies for overcoming these problems and to assist in better identification and characterisation of inhibitors. METHODS Forty-two laboratories blind tested a set of eight samples for the presence or absence of inhibitors. These included true factor inhibitors (FVIII and FV), and other samples that reflected potential pre-analytical variables (e.g., heparin contamination, serum, EDTA plasma, aged plasma) that might arise and complicate inhibitor detection or lead to false inhibitor identification. RESULTS There was a wide scatter of inhibitor results, with false positive and false negative inhibitor identification, and mis-identification of inhibitors (e.g., FVIII inhibitor identified where FV inhibitor present). Further analysis of the pattern of reported laboratory results, including routine coagulation testing and factor profiles, allowed some additional interpretative power to provide strategies that will assist laboratories to improve the accuracy of inhibitor identification in the future. CONCLUSIONS There are currently occasional lapses in factor inhibitor identification, which this report will hopefully help address.
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McHugh G, Kiely D, Low J, Healy ML, Hayes C, Clarke S. Importation of Polish trichinellosis cases to Ireland, June 2007. ACTA ACUST UNITED AC 2007; 12:E070719.3. [PMID: 17868558 DOI: 10.2807/esw.12.29.03239-en] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A Polish national in his late 20s presented in June to the emergency department of a hospital in Dublin.
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Mackenzie MJ, Saltman D, Hirte H, Low J, Johnson C, Pond G, Moore MJ. A Phase II study of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP) and gemcitabine in advanced pancreatic carcinoma. A trial of the Princess Margaret hospital Phase II consortium. Invest New Drugs 2007; 25:553-8. [PMID: 17585372 DOI: 10.1007/s10637-007-9066-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 05/10/2007] [Indexed: 10/23/2022]
Abstract
3-Aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP, Triapine, Vion Pharmaceuticals, New Haven, CT) is an inhibitor of the M2 subunit of ribonucleotide reductase (RR). Preclinical testing demonstrates synergy between 3-AP and gemcitabine. Phase I studies of the combination have suggested tolerability and some initial evidence of efficacy. Therefore, a phase II study of gemcitabine plus 3-AP in advanced pancreatic carcinoma was undertaken. In this two-step phase II trial, patients with advanced pancreatic adenocarcinoma who had not received prior chemotherapy for advanced disease were treated with 3-AP 105 mg/m(2) given over 2 h. Four hours after the 3-AP infusion was completed, gemcitabine 1,000 mg/m(2) was given over 30 min. Both drugs were given on days 1, 8 and 15 of a 28-day cycle.Twenty-six patients were enrolled to the study. One patient withdrew consent prior to receiving any treatment and is excluded from all further analyses. Four patients discontinued treatment due to adverse effects. Grade 3/4 hematological adverse events included neutropenia, thrombocytopenia, lymphopenia, leukopenia and anemia and the most frequent non-hematological adverse events were fatigue and pain. No objective responses were observed. Eleven patients had stable disease (SD). In five of these eleven patients, SD lasted for more than 6 months. The median time to progression was 4.1 months and the 6 month progression-free survival rate was 29%. The median survival was 9.0 months with a 1-year survival of 28.0%. The combination of 3-AP and gemcitabine is associated with moderate toxicity in patients with advanced pancreatic cancer. This two-stage trial was stopped after stage I due to lack of antitumour activity. On the basis of this clinical trial, the combination of gemcitabine and 3-AP at this dose and schedule does not warrant further study in this patient population.
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Kummar S, Kinders R, Gutierrez M, Rubinstein L, Parchment RE, Phillips LR, Low J, Murgo AJ, Tomaszewski JE, Doroshow JH. Inhibition of poly (ADP-ribose) polymerase (PARP) by ABT-888 in patients with advanced malignancies: Results of a phase 0 trial. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.3518] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
3518 Background: Inhibition of PARP activity sensitizes tumor cells to the effects of DNA damaging agents. We conducted a phase 0 pharmacokinetic (PK) and pharmacodynamic (PD) study of ABT-888, an oral inhibitor of PARP. Methods: The objectives were to determine a dose range at which ABT-888 inhibits PARP in tumor tissue and in peripheral blood mononuclear cells (PBMC); and the PK of ABT-888. Patients with advanced solid tumors refractory to at least one line of therapy were eligible; patients with CLL or follicular lymphomas were also eligible if standard therapy was not currently indicated. A single oral dose of ABT-888 was administered per patient, dose escalations were planned in cohorts of 3 patients each (10 mg, 25 mg, 50 mg, 100 mg, and 150 mg). PBMC and tumor sampling were performed before and after drug administration for real time PK and PD analyses. All patients underwent PBMC sampling; tumor biopsies were planned once significant inhibition of PARP activity in PBMCs was seen in 1 of 3 patients in a cohort or plasma Cmax of 210 nM was achieved in at least 1 patient. Tumor biopsies were performed at baseline in the week prior to drug administration and then 3–6 hours post drug administration. Significant inhibition of PARP activity was defined as at least 0.69 reduction on the log scale, which also satisfied statistical significance. Results: A total of 6 patients have been studied so far, 3 each for the 10 mg and 25 mg cohorts. No treatment related adverse events have been observed. Target Cmax was exceeded in the first cohort, all patients in the next cohort underwent tumor biopsies in addition to PBMC sampling. A trend towards inhibition of PARP activity in PBMCs was observed in the first cohort. Significant inhibition of PAR levels was observed in tumor biopsies from all 3 patients in the second cohort (92%, 99%, 100% reductions respectively, as compared to baseline). Greater than 85% reduction of PAR levels was observed in PBMCs from 2 of the 3 patients in the second cohort (one patient was not evaluable). Conclusions: ABT-888 is orally bioavailable and inhibits PARP activity in PBMCs and tumor cells. Target assay feasibility was established in human samples. Funded in part by NCI Contract N01-CO-12400 No significant financial relationships to disclose.
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Rubinstein LV, Steinberg SM, Kummar S, Low J, Parchment R, Kinders R, Gutierrez M, Murgo AJ, Doroshow JH, Tomaszewski J. Statistical considerations for a phase 0 trial. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.14038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
14038 Background: Phase ‘0’ clinical trials are small first in man studies to determine a dose or dose range which results in a desired biologic effect. Novel statistical designs are needed due to the limited number of patients and the complexities of analyzing primary pharmacodynamic endpoints. Methods: In general, the effect of the agent will be evaluated, based on a biologic endpoint(s), at two levels, the individual participant level (for a given dose amount), and the agent dose amount level (across individual participants). At the participant level, the effect is preferably defined as a dichotomous outcome. The statistical criteria should be such that the threshold is not surpassed with more than .10 probability, for a given participant, at a given dose amount, for the null hypothesis case of no true biologic effect. At the dose amount level, the effect rate is defined as the probability that a randomly chosen participant will satisfy the participant level threshold. The statistical criteria for declaring an observed effect rate to be significant should be such that the over-all probability of declaring the agent effective (summed across all dose amounts) should not exceed .10 for the null hypothesis case of no true biologic effect. A target effect rate, measured across participants, should be given, and the power to detect it, for a given dose amount, should be estimated. Ideally, there will be multiple pre-agent administration endpoint measurements, per participant, to define variability. Examples: 1. If 10 participants are accrued to a single dose amount, an observed effect rate for that dose amount could be defined to be significant if at least 2 of the 10 participants satisfy the participant threshold, yielding 85–90% power to detect a 35% effect rate. 2. If 5 participants are accrued to each of 2 dose amounts, an observed effect rate for a particular dose amount could be defined to be significant if at least 2 of the 5 participants satisfy the participant threshold, yielding approximately 90% power to detect a 60% effect rate. 3. If 3 participants are accrued to each of 4 dose amounts, an observed effect rate for a particular dose amount could be defined to be significant if at least 2 of the 3 participants satisfy the participant threshold, yielding approximately 90% power to detect an 80% effect rate. No significant financial relationships to disclose.
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Weed KH, MacEwen CJ, Giles T, Low J, McGhee CNJ. The Dundee University Scottish Keratoconus study: demographics, corneal signs, associated diseases, and eye rubbing. Eye (Lond) 2007; 22:534-41. [PMID: 17237755 DOI: 10.1038/sj.eye.6702692] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
AIM To investigate and correlate the corneal, refractive, topographic and familial characteristics of a large cohort with keratoconus. METHODS Prospective observational study of 200 consecutive patients presenting with keratoconus during the 4 year-period 1997-2000. Subjects were examined at enrolment and at a final review. Data were collected on demographic characteristics, referral route, symptoms, refractive correction, eye rubbing, family history, medical history, slit-lamp biomicroscopic corneal signs, and computerized corneal topography. RESULTS Mean age at enrolment was 30.9+/-10.4 (range, 12.2-72) years (N=200, 62.5% male, 93% white Caucasian) with a 5% family history of keratoconus. Atopic diseases included asthma (23%), eczema (14%), and hay fever (30%). Only 9% wore contact lenses before referral. Mean follow-up was 1004 days +/-282 (range, 390-1335) and 9.7+/-8.9 (range, 1.1-60) years from diagnosis. The mean simulated K1 corneal power at enrolment was 51.74+/-5.36 (range, 42.59-67.32) D and 88.5% exhibited bilateral keratoconus. Fifty-three (15%) topographically confirmed cones exhibited no clinical corneal signs at presentation. At enrollment, 56% had a pachymetry <0.480 mm increasing to 77% at final review. Forty-eight percent of subjects reported significant eye rubbing and there was a highly statistically significant difference (two sample t-test P=0.018) between keratoconus and control groups. TMS-2 axial corneal power was strongly associated with corneal scarring and age at diagnosis. The size of the scarring effect was 2.2 D (95% confidence interval (CI) 1.34, 3.06). CONCLUSIONS This study provides an overview of a large population with keratoconus highlighting presenting features and clinical and topographic progression over a 4 year-period.
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Sheen CR, Low J, Joseph J, Kotlyar E, George PM, Brennan SO. Fibrinogen Darlinghurst: hypofibrinogenaemia caused by a W253G mutation in the gamma chain in a patient with both bleeding and thrombotic complications. Thromb Haemost 2006; 96:685-7. [PMID: 17080227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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Favaloro EJ, Bonar R, Aboud M, Low J, Sioufi J, Wheeler M, Lloyd J, Street A, Marsden K. How useful is the monitoring of (low molecular weight) heparin therapy by anti-Xa assay? A laboratory perspective. ACTA ACUST UNITED AC 2005; 11:157-62. [PMID: 16174600 DOI: 10.1532/lh96.05028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have conducted a series of laboratory-based surveys to assess variability in assay results utilized to monitor heparin anticoagulant therapy. These surveys involved laboratories participating in the Haematology component of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP). Thirty five of 646 laboratories that were sent a preliminary questionnaire indicated that they performed anti-Xa assays and these laboratories were sent a panel of four plasma samples. These plasma samples contained respectively: (i) no added heparin, (ii) low molecular weight heparin (LMWH), enoxaparin, added to a level of approximately .5 U/mL, (iii) unfractionated heparin added to a level of approximately .5 U/mL, and (iv) LMWH added to a level of approximately 1.0 U/mL. Tests to be performed were the activated partial thromboplastin time (APTT), the thrombin time (TT), fibrinogen, and anti-Xa. As expected, returned results for APTT and TT showed some elevation in heparinized samples while fibrinogen assays were not affected. Anti-Xa assays yielded the following results (median [range]): (i) .01 [0-.11], (ii) .43 [.33-.80], (iii) .23 [.10-.49], and (iv) .90 [.60-1.30]. Thus, although median values were close to those anticipated, there was a wide variation in returned results. In a repeat exercise a few months later laboratories were also asked about their therapeutic ranges (TRs) and provided with an additional vial of LMWH-spiked (1.0 U/mL) plasma labeled as 'heparin-standard' to be used as an assay calibrant. TRs varied substantially between laboratories, from low ranges of .2-.4 to high ranges of .8-1.2. Anti-Xa assay results were similar to those of the first survey: (median [range]): (a) repeat testing: (i) .02 [0-.28], (ii) .47 [.34-.80], (iii) .25 [.14-.58], (iv) .95 [.65-1.31]; (b) repeat testing using survey provided 'heparin-standard': (i) .02 [0-.24], (ii) .55 [.4-.83], (iii) .28 [.10-.63], (iv) 1.00 [.9-1.16]. Thus using the provided 'heparin-standard' yielded lower variability in results for LMWH. In conclusion, the high variability of anti-Xa assay results coupled with the widely variable TRs suggests that therapeutic heparin monitoring is poorly standardized, and this raises some concerns over the clinical value of such monitoring.
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Exner T, Joseph JE, Connor D, Low J, Ma DDF. Increased procoagulant phospholipid activity in blood from patients with suspected acute coronary syndromes: a pilot study. Blood Coagul Fibrinolysis 2005; 16:375-9. [PMID: 15970723 DOI: 10.1097/01.mbc.0000173465.45613.a3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Increased platelet activation is well documented in patients with acute coronary syndromes and can be detected by various methods, including flow cytometry and enzyme-linked immunosorbent assay. However, such techniques require several steps and cannot provide quick results. Platelet activation ultimately results in procoagulant phospholipid exposure and we have previously described a simple activated factor X-activated clotting time (XACT) test that is insensitive to resting platelets but that is significantly shortened by activated platelets, microparticles and procoagulant phospholipids. Our aim was to determine whether the XACT test could be used to distinguish patients with chest pain due to cardiac ischaemia from those having chest pain due to non-cardiac causes. We thus carried out XACT tests on ethylenediamine tetraacetic acid whole blood and plasma samples obtained from 46 patients presenting to the emergency department with chest pain and from 30 controls. Sixteen cases (30%) were subsequently diagnosed as acute coronary syndromes. Blood samples from these patients displayed overall significantly shortened XACT results relative to both healthy controls (P<0.001) and chest pain not due to cardiac ischaemia (P<0.004). This discrimination was much better with whole blood samples than when platelet-poor plasmas were tested (P=0.153), suggesting that free microparticles were not the only factors responsible. Thus, the detection of increased procoagulant phospholipid activity in whole blood by shortened XACT results may be a simple and rapid diagnostic marker of some cardiac ischaemic events.
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Favaloro EJ, Bonar R, Sioufi J, Wheeler M, Low J, Aboud M, Lloyd J, Street A, Marsden K. An international survey of current practice in the laboratory assessment of anticoagulant therapy with heparin. Pathology 2005; 37:234-8. [PMID: 16175898 DOI: 10.1080/00313020500098900] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
AIMS We conducted a survey of laboratory practice for assessment of heparin anticoagulant therapy by participants of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP). METHODS A questionnaire was sent to 646 laboratories enrolled in the Haematology component of the QAP, requesting details of tests used for monitoring heparin therapy. RESULTS Seventy laboratories (10.8%) returned results that indicated that they performed laboratory monitoring of heparin therapy. Most laboratories (69/70 = 98.6%) use the activated partial thromboplastin time (APTT) to monitor unfractionated heparin, with eight (11.4%) also using the APTT for monitoring low molecular weight (LMW) heparin. Five (7.1%) laboratories use the thrombin time (TT) test to help monitor heparin therapy and 37 (52.9%) laboratories use an anti-Xa assay to monitor heparin (either LMW or unfractionated). Normal reference ranges (NRR) for APTT differed considerably between laboratories, even those using the same reagent. Therapeutic ranges (TR) also differed considerably between laboratories, for both APTT and the anti-Xa assay. Laboratory differences in NRR and TR using the same reagents could only be partly explained by the use of different instrumentation. CONCLUSIONS There is a large variation in current laboratory practice relating to monitoring of heparin anticoagulant therapy. This finding is similar to that of a similar survey conducted by the RCPA QAP almost a decade ago. This study suggests that better standardisation is still required for laboratory monitoring of heparin therapy.
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Mackenzie MJ, Moore MJ, Saltman D, Zbuk KM, Vandesompele E, Lovell S, Degendorfer P, Johnson C, Siu L, Low J. A phase II study of triapine in combination with gemcitabine in advanced pancreatic carcinoma: A Princess Margaret Hospital Phase II Consortium Trial. J Clin Oncol 2005. [DOI: 10.1200/jco.2005.23.16_suppl.4093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Joseph JE, Low J, Courtenay B, Neil MJ, McGrath M, Ma D. A single-centre prospective study of clinical and haemostatic risk factors for venous thromboembolism following lower limb arthroplasty. Br J Haematol 2005; 129:87-92. [PMID: 15801960 DOI: 10.1111/j.1365-2141.2005.05419.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous studies report conflicting results concerning the potential significance of thrombophilic genotypes in postarthroplasty venous thromboembolism (VTE). This study assessed thrombophilic genotypes, haemostatic and clinical variables as independent risk factors for VTE postarthroplasty. A total number of 569 patients undergoing elective lower limb arthroplasty at a single centre were prospectively studied. All patients were interviewed and had blood samples collected preoperatively. Bilateral lower limb ultrasonography was performed at day 7 +/- 2 postoperatively in all patients (ventilation/perfusion lung scanning in symptomatic patients only). The incidence of inhospital postoperative VTE was 26%. In univariate analysis - increased age, knee arthroplasty, recent surgery, general anaesthesia, shorter operation time, non-receipt of blood transfusion and differences in surgical practice (including use of pneumatic calf compression, surgical drains and postoperative bandaging techniques) were significantly associated with VTE. Factor V Leiden, prothrombin G20210A and MTHFR C677T mutations were not significant risk factors for VTE, and of all haemostatic variables tested, only median activated partial thromboplastin time showed significant difference between VTE and non-VTE patients (34 s vs. 33 s). Multiple logistic regression analysis demonstrated that increased age, knee arthroplasty and individual surgeon's routine practices were the only significant independent risks for VTE; hence routine preoperative blood screening for a potential hypercoaguable state is not indicated in this surgical setting.
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Pimentel JD, Low J, Styles K, Harris OC, Hughes A, Athan E. Control of an outbreak of multi-drug-resistant Acinetobacter baumannii in an intensive care unit and a surgical ward. J Hosp Infect 2005; 59:249-53. [PMID: 15694983 DOI: 10.1016/j.jhin.2004.09.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Accepted: 09/19/2004] [Indexed: 11/21/2022]
Abstract
We describe an outbreak of multi-drug-resistant Acinetobacter baumannii (MRAB) that occurred in an intensive care unit (ICU) and a surgical ward from December 2003 to March 2004. Mapping patient movements on a timeline indicated that the outbreak was confined to these two areas. Investigation by the hospital's infection prevention service found that a possible source of spread was improper cleaning methods used on respiratory equipment. Pulsed-field gel electrophoresis analysis of available isolates indicated the presence of two distinct strains. One strain was seen in patients from the ICU and the other strain was seen in the surgical ward patients. Cleaning and environmental decontamination as well as staff education were implemented to halt further immediate spread. The deficiencies identified during the investigation were also resolved. The final outcome was the successful termination of this outbreak.
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Favaloro EJ, Bonar R, Sioufi J, Wheeler M, Low J, Aboud M, Duncan E, Smith J, Exner T, Lloyd J, Marsden K. Multilaboratory Testing of Thrombophilia: Current and Past Practice in Australasia as Assessed through the Royal College of Pathologists of Australasia Quality Assurance Program for Hematology. Semin Thromb Hemost 2005; 31:49-58. [PMID: 15706475 DOI: 10.1055/s-2005-863805] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We have conducted a series of multilaboratory surveys during the last 6 years to evaluate testing proficiency in the detection of congenital and acquired thrombophilia. For lupus anticoagulant (LA) testing, participant laboratories used a panel of tests, including activated partial thromboplastin time (aPTT; 100% of laboratories), kaolin clotting time (26 to 70%), and Russell's viper venom time (RVVT; 75 to 100%). Coefficients of variation (CVs) for assays ranged from 5 to 40%. RVVT assays appeared to be most sensitive and specific for detection of LA (fewer false-negatives or -positives), although laboratories performed best when they used a panel of tests. For congenital thrombophilia, tests evaluated comprised protein C (PC), protein S (PS), antithrombin (AT), and activated protein C resistance (APCR). Most participant laboratories performed PC using chromogenic (approximately 75%), or clot based (approximately 15%) assays, with few (< 10%) performing antigenic assessments. PS was most often assessed (approximately 60%) by immunological or antigenic assays, usually of free PS, or by functional or clot-based assays (approximately 40%). AT is usually assessed by functional chromogenic assays (approximately 95%). APCR was assessed using aPTT (approximately 50%) or RVVT (approximately 50%) clot-based assays, with the aPTT APCR typically performed using factor V-deficient plasma predilution, but the RVVT APCR typically performed without. Laboratories using the RVVT APCR generally performed better in detection of factor V Leiden-associated APCR, with the aPTT method group yielding higher false-negative and/or false-positive findings (approximately 5% of occasions). Some clot-based PC and PS assays appeared to be influenced by APCR status, and yielded lower apparent PC and PS levels with positive APC resistance. The overall error rate for PC, PS, and AT was approximately 2 to 8% (i.e., false-normal interpretations for deficient plasma or false-abnormal interpretations for normal plasma). The CVs for these assays ranged from 5 to 40%, with highest CVs typically obtained with PS assays.
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Favaloro EJ, Posen J, Ramakrishna R, Soltani S, McRae S, Just S, Aboud M, Low J, Gemmell R, Kershaw G, Coleman R, Dean M. Factor V inhibitors. Blood Coagul Fibrinolysis 2004; 15:637-47. [PMID: 15613918 DOI: 10.1097/00001721-200412000-00003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Acquired deficiencies of, or inhibitors to, factor V are considered rare events. We report a series of 14 acquired factor V deficiencies, 10 of which were confirmed to have inhibitors to factor V, as identified within Australia in the past 5 years following a multi-laboratory investigation. The initial index case seen by one laboratory was followed within 4 months by a separate similar case. This prompted local contact with colleagues (n = 20) working in other haemostasis referral laboratories to identify the current case series. In total, nearly one-half of all haemostasis referral laboratories contacted had seen a case within the past 5 years. Clinical features and the apparent associated risk of bleeding complications generally varied, as did laboratory findings and the likely causal event. There were three females and 11 males. Age ranged from 44 to 95 years (median, 81 years). The level of inhibitor ranged from undetectable to over 250 Bethesda units. The probable cause leading to development of the inhibitors ranged from exposure to bovine thrombin, exposure to antibiotics, surgery and malignancy. Of additional interest was the apparent association of anti-phospholipid antibodies in many of the cases. For example, in the two similar index cases, with factor V inhibitor titres > 200 Bethesda units, high levels of anti-cardiolipin antibodies (> 70 GPL units) were also detected. Although less clear because of inhibitor interference, many of the cases also showed evident co-associated lupus anticoagulant activity. In conclusion, we report a series of factor V inhibitors recently identified within our geographic region that would represent an annual incidence of around 0.29 cases per million Australians. Although considered a rare finding, there is a high likelihood that most haemostasis referral laboratories will see a case every five or so years.
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Singer W, Spies JM, McArthur J, Low J, Griffin JW, Nickander KK, Gordon V, Low PA. Prospective evaluation of somatic and autonomic small fibers in selected autonomic neuropathies. Neurology 2004; 62:612-8. [PMID: 14981179 DOI: 10.1212/01.wnl.0000110313.39239.82] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND There are a number of distal and generalized small-fiber neuropathies. The neuropathologic basis is poorly understood as somatic and autonomic C fibers are not usually studied in the same region of the body. OBJECTIVE To evaluate prospective somatic and autonomic C-fiber function in 11 healthy control subjects and 38 patients with different clinical patterns of neuropathy. METHODS Distal small-fiber neuropathy (DSFN), peripheral neuropathy (PN), diabetic neuropathy (DN), neuropathic postural tachycardia syndrome (POTS), and idiopathic autonomic neuropathy (IAN) were evaluated. Intraepidermal nerve fiber density was used to evaluate distal somatic C fibers. Both quantitative sudomotor axon reflex test and skin norepinephrine content were measured for the biopsy site to assess distal autonomic C-fiber function. Postganglionic sudomotor, adrenergic, and cardiovagal functions were evaluated by autonomic reflex testing and quantified using a Composite Autonomic Severity Scale. RESULTS Skin norepinephrine concentration was significantly related to CASS. DN was associated with somatic and autonomic C-fiber impairment with good agreement. POTS was associated with selective distal autonomic deficit. DSFN had combined distal somatic and C-fiber impairment. IAN showed combined and selective distal and generalized autonomic C-fiber impairment. The somatic neuropathies had C-fiber impairment affecting both populations to varying degrees. CONCLUSION Although a general agreement exists between the loss of somatic C fibers and autonomic deficits, selective involvement occurs for specific autonomic neuropathies.
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Exner T, Low J. Detection of procoagulant phospholipid interfering in tests for lupus anticoagulant. Thromb Res 2004; 114:547-52. [PMID: 15507290 DOI: 10.1016/j.thromres.2004.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 05/29/2004] [Accepted: 06/01/2004] [Indexed: 11/26/2022]
Abstract
Excess platelets shorten most clotting tests for lupus anticoagulant (LA). Often it is not clear if a shortened, normal or slightly prolonged result in a test masks a weak LA in combination with activated platelets, which express procoagulant phospholipid (PPL). Our aim was to investigate a new LA-insensitive factor Xa-activated clotting time (XACT) test for detecting PPL in plasma specimens submitted for LA testing. In most clotting tests for PPL, specimens are mixed with human platelet-free plasma (PFP) to correct for factor defects. Such tests are usually very sensitive to prolongation by LA, which act against PPL-human clotting factor complexes. We found that phospholipid-free plasma from pigs could be used instead of human platelet-free plasma as substrate plasma without reducing sensitivity of XACT to PPL. However, the pig plasma-based system was significantly less affected by most LA. Activated platelets were detectable despite the presence of most LA. Since some LA still had significant prolonging effect on the XACT despite the use of pig plasma we investigated this further. ELISAs for IgG and IgM anti-beta2GP1 and anti-prothrombin antibodies were carried out on 23 specimens. We did not find that LA in plasmas displaying anti-prothrombin antibodies had less prolonging effect on the test based on pig plasma than that using human platelet-free plasma. Similarly, there were no subtyping trends apparent among results from anti-beta2GPI-positive samples. Our results do not support the concept that anti-prothrombin-dependent LA might be more species specific than anti-beta2GPI-dependent LA.
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Exner T, Joseph J, Low J, Connor D, Ma D. A new activated factor X-based clotting method with improved specificity for procoagulant phospholipid. Blood Coagul Fibrinolysis 2003; 14:773-9. [PMID: 14614360 DOI: 10.1097/00001721-200312000-00015] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An improved activated factor X-based clotting method was used to investigate activity of procoagulant phospholipid (PPL) in blood samples collected into various anticoagulants and in plasmas with a range of abnormalities. The dilute activated factor X-activated clotting time (XACT) was carried out on a mixture of specimen with phospholipid-free porcine plasma. PPL from the test sample is then rate-limiting, controlling the clotting time so that the XACT is shortened from a maximum of approximately 120 s with citrated platelet-free plasma to approximately 30 s with freeze-thawed platelet-rich plasma. XACT results were only shortened slightly by fresh normal platelet-rich plasma, but were shortened significantly by platelets that had been activated by freeze-thawing. This improved method for PPL was not prolonged by deficiencies of known clotting factors and therapeutic levels of heparin, and it was surprisingly resistant to most lupus anticoagulants. However, it was extremely sensitive to PPL, detecting down to 50 ng/ml synthetic phospholipid added to phospholipid-free plasma. Excellent correlation was achieved between XACT shortening and microparticle count assessed by annexin V-binding and flow cytometry in normal plasma spiked with platelet microparticles. In citrated blood specimens, XACT shortened with time in a temperature-dependent manner. XACT results on blood samples anticoagulated with ethylenediamine tetra-acetate were more stable, and these would be preferable for assessing PPL expression ex vivo. XACT was significantly shorter in whole blood samples than in normal platelet-rich or platelet-poor plasmas, suggesting that PPL was normally expressed more by cells or aggregates larger than platelets or microparticles.
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Wilkinson S, Fellowes D, Goodman M, Low J, Harvey F. 1236 District nurses perceptions of a home based nursing service for dying patients: a national survey of reasons for referral and non-referral. EJC Suppl 2003. [DOI: 10.1016/s1359-6349(03)91262-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Chia YN, Tay EH, Cheong DM, Eu KW, Low J, Ho TH, Yam KL. Bowel surgery for epithelial ovarian cancer--an early case series. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2003; 32:661-4. [PMID: 14626798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
OBJECTIVES The aims of this study were to review our local experience with bowel surgery for epithelial ovarian cancer at the Gynaecological Cancer Centre, KK Women's and Children's Hospital, and to document the outcome of such surgery as well as their complication rates. MATERIALS AND METHODS The retrospective medical records of 38 patients with epithelial ovarian cancer who underwent surgery including bowel surgery from January 1997 to May 2002 at the Gynaecological Cancer Centre, KK Women's and Children's Hospital, Singapore, were reviewed. RESULTS Indications for surgery were predominantly debulking of disease. Fifty-eight per cent of patients had primary debulking surgery, 34% had debulking of recurrence and 3% had interval debulking. Only 5% of patients had bowel obstruction as the only indication for surgery. Rectosigmoid resection was the most common bowel operation overall, being performed in 76.3% of patients. The stoma rate for rectosigmoid resection was 61%. The remaining procedures included 7 colectomies, 1 intestinal bypass procedure and 1 intestinal diversion procedure. Optimal debulking (defined as < 1 cm of residual disease) was achieved in the majority (71%). The median operating time was 4 hours. The median blood loss was 1300 mL. The major complication rate was 10.5%. Major complications encountered were as follows: 1 patient (2.6%) had an anastomotic leak, 2 patients (5.3%) had intra-abdominal abscess and 1 patient (2.6%) developed intestinal fistula. Three patients (7.8%) required a re-operation within 30 days. There were 3 deaths (7.8%) within 30 days of surgery. CONCLUSION Bowel surgery is commonly indicated for epithelial ovarian cancer to facilitate optimal debulking. Such surgery is feasible with acceptable complication rates in our local centre.
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Song Y, Sun KL, Bratton L, Unangst P, Miller S, Low J, Gong H, Heilig D, Trivedi B. 1P-0206 Discovery and profile of β-keto-sulfone analogs: Potent, selective, and novel CCR2 receptor antagonists. ATHEROSCLEROSIS SUPP 2003. [DOI: 10.1016/s1567-5688(03)90277-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Low J. Management of purpura fulminans. Br J Anaesth 2001; 87:650. [PMID: 11878745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
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Roderick P, Low J, Day R, Peasgood T, Mullee MA, Turnbull JC, Villar T, Raftery J. Stroke rehabilitation after hospital discharge: a randomized trial comparing domiciliary and day-hospital care. Age Ageing 2001; 30:303-10. [PMID: 11509308 DOI: 10.1093/ageing/30.4.303] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To compare the effectiveness and costs of a new domiciliary rehabilitation service for elderly stroke patients with geriatric day-hospital care. DESIGN Randomized controlled trial. PARTICIPANTS Stroke patients aged 55+ who required further rehabilitation after hospital discharge or after referral to geriatricians from the community. SETTING Poole area, East Dorset, a mixed urban/rural area on the south coast of England. MAIN OUTCOMES Primary-changes between hospital discharge and 6-month follow-up in physical function as measured by Barthel index. Secondary-changes over this period in Rivermead Mobility Index and mental state (Philadelphia Geriatric Centre Morale Scale) and differences in social activity (Frenchay Activities Index) and generic health status (SF-36). Health service and social service cost per patient were compared for the two groups. RESULTS 180 patients were eligible and 140 (78%) were randomized. The groups were well balanced for age, sex, social class and initial Barthel index. We achieved follow-up in 88% of subjects who were alive at 6 months. We detected no significant differences in patient outcomes, although there was a non-significant improvement in measures of physical function and social activity in the domiciliary group. Domiciliary patients had more physiotherapy time per session and more district nurse time, and made greater use of social service day centres and home helps. Total cost per patient did not differ significantly between the two groups, with reduced health service costs in the domiciliary arm offset by higher social service costs. CONCLUSION No significant differences were detected in the effectiveness of the two services. Neither service influenced patients' mental state, and their social activity remained low. Total costs were similar. A mixed model of day-hospital and domiciliary care may be most cost-effective for community stroke rehabilitation, but this requires further evaluation.
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