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Steve Thomas

Publications and source records attributed to Steve Thomas.

8 recordsLinked to original sources
PubMed2005

Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis.

BACKGROUND: Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy. METHODS: We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance. RESULTS: We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography. CONCLUSION: Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data.

Journal Article↗
PubMed2004

Endovascular treatment of thoracic aortic diseases: combined experience from the EUROSTAR and United Kingdom Thoracic Endograft registries.

PURPOSE: The objective of this study was to assess the initial and 1-year outcome of endovascular treatment of thoracic aortic aneurysms and dissections collated in the European Collaborators on Stent Graft Techniques for Thoracic Aortic Aneurysm and Dissection Repair (EUROSTAR) and the United Kingdom Thoracic Endograft registries. METHODS: Four hundred forty-three patients underwent endovascular repair of thoracic aortic disease between September 1997 and August 2003 (EUROSTAR, 340 patients; UK, 103 patients). Patients represented 4 major disease groups: degenerative aneurysm (n = 249), aortic dissection (n = 131), false anastomotic aneurysm (n = 13), and traumatic aortic injury (n = 50). RESULTS: Mean age in the entire study group was 63 years. Fifty-two percent of patients were deemed at high risk for open surgery because of major comorbidity. Sixty percent of patients underwent an elective procedure, and 35% required emergency treatment. Conventional indications for treatment of aortic dissection, including aortic expansion, continuous pain, rupture, or symptoms of branch occlusion constituted the basis for endograft placement in 57% of patients, whereas in 43% of patients aortic dissections were asymptomatic. Primary technical success was obtained in 87% of patients with degenerative aneurysm and in 89% with aortic dissection. Paraplegia was a postoperative complication in 4.0% of patients with degenerative aneurysm and 0.8% of patients with aortic dissection (not significant). Thirty-day mortality in the entire study group was 9.3%, with mortality rates after elective procedures of 5.3% for degenerative aneurysms and 6.5% for aortic dissection. Mortality for degenerative aneurysm after emergency repair was higher (28%; P <.0001) then after elective procedures. For aortic dissection the emergency repair rate was 12% (not significant compared with elective repair of aortic dissection, and P = .025 compared with emergency repair of degenerative aneurysm). One-year follow-up was complete in 195 patients. The outcome at 1 year was more favorable for aortic dissection than for degenerative aneurysm with regard to aortic expansion (0% vs 15%; P = .001) and late survival (90% vs 80%; P = .048). In the groups with false anastomotic aneurysm and traumatic aortic injury, 30-day mortality rates were 8% and 6%, respectively. CONCLUSION: This multicenter experience demonstrates acceptable rates for operative mortality and paraplegia after endovascular repair of thoracic aortic disease. Outcome after 30 days and 1 year was more favorable for aortic dissection than for degenerative aneurysm. However, the durability of this technique is currently unknown, and continued use of registries should provide data from long-term follow-up.

Adolescent↗
PubMed2003

Investigating mechanisms involved in the self-incompatibility response in Papaver rhoeas.

Sexual reproduction in flowering plants is controlled by recognition mechanisms involving the male gametophyte (the pollen) and the female sporophyte (the pistil). Self-incompatibility (SI) involves the recognition and rejection of self- or incompatible pollen by the pistil. In Papaver rhoeas, SI uses a Ca(2+)-based signalling cascade triggered by the S-protein, which is encoded by the stigmatic component of the S-locus. This results in the rapid inhibition of incompatible pollen tube growth. We have identified several targets of the SI signalling cascade, including protein kinases, the actin cytoskeleton and nuclear DNA. Here, we summarize progress made on currently funded projects in our laboratory investigating some of the components targeted by SI, comprising (i) the characterization of a pollen phosphoprotein (p26) that is rapidly phosphorylated upon an incompatible SI response; (ii) the identification and characterization of a pollen mitogen-activated protein kinase (p56), which exhibits enhanced activation during SI; (iii) characterizing components involved in the reorganization and depolymerization of the actin cytoskeleton during the SI response; and (iv) investigating whether the SI response involves a programmed cell death signalling cascade.

Actins↗
PubMed2002

A 90-day oral gavage toxicity study of D-methylphenidate and D,L-methylphenidate in Sprague-Dawley rats.

D-methylphenidate is an enantiomer of D,L-methylphenidate and was developed as an improved treatment for attention deficit hyperactivity disorder in children. The current study was performed to determine and compare the toxicity of 2-50 mg/kg per day D-MPH and 100 mg/kg per day D,L-MPH for 90 days in rats with the top D-MPH dose being equimolar to 100 mg/kg D,L-MPH. The top D-MPH and D,L-MPH doses were at least 67 times that of the human dose and produced systemic exposures that were over 10 times higher than those typically achieved in children. During the course of the study, one male each from the 50 mg/kg per day and D,L-MPH groups and one female from the 50 mg/kg group died. Incidences of material around nose/eyes, scabbing, foot swelling, alopecia and abrasions were evident at 50 mg/kg per day D-MPH and 100 mg/kg per day D,L-MPH doses. Body weight and its changes decreased in a dose-dependent manner for D-MPH males. There were significant changes in some clinical chemistry measurements at the terminal bleed in the high dose groups of both sexes although most of these changes were resolved by the recovery bleed. Differences in absolute and relative body and certain organ weights for high dose D-MPH and D,L-MPH groups were seen at terminal necropsy with the differences no longer present after the recovery period. No abnormal or gross histopathological changes were associated with any of these organ weight changes reported for the terminal and recovery periods. Based on body weight changes, the no observed adverse effect level for D-MPH in rats was 20 mg/kg. Overall, the toxicity profile observed in rats with 50 mg/kg per day D-MPH was comparable to that of an equimolar dose of D,L-MPH (100 mg/kg per day) when given repeatedly for 90 days using a twice a day dosing regimen.

Administration, Oral↗
PubMedDate not supplied

Laboratory-based evaluation of a compression-bandaging system.

Graduate external compression is a key factor in the successful treatment of venous leg ulcers, but can be damaging if used inappropriately. A new type of bandage has been designed to minimise the risk of tissue damage by controlling the amount of tension within the bandage during application. This laboratory study suggests that the bandage meets its design criteria, and highlights the importance of correct application to avoid excessive sub-bandage pressure.

Ankle↗