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Biomedical subjects

Michael J Clarke

Publications and source records attributed to Michael J Clarke.

5 recordsLinked to original sources
PubMed2004

Individual patient data meta-analyses.

Systematic reviews help people to make well-informed decisions about health care by bringing together the relevant evidence, appraising it and, where appropriate, combining it in a meta-analysis. The ultimate aim for a systematic review should be to present all relevant data on all participants in all research judged to be eligible for the review. In reviews of the effects of interventions, this ultimate aim would be met through the collection and analyses of the results of all relevant randomized trials. Reviews that use individual patient data achieve this by the central collection and analyses of data on each participant in the trials. It allows the reviewer to overcome many of the problems associated with a reliance on published data alone, and some of the problems associated with using aggregate data supplied by the trialist, and will add to the analyses that can be performed. This chapter discusses the rationale for individual patient data reviews and describes some of their features.

Data Collection↗
PubMed2003

Autologous deep vein reconstruction of infected thoracoabdominal aortic patch graft.

Graft infection remains a serious complication of prosthetic aortic repair. Infection of thoracoabdominal aortic prosthetic grafts, in particular, is a significant clinical challenge and is associated with high mortality. We report successful in situ reconstruction of an infected thoracoabdominal aortic prosthetic patch graft with autogenous superficial femoral vein. To our knowledge, this is the first such case described in the North American and English language surgical literature. At 24-month follow-up the patient remains well, with no evidence of sepsis or graft complication at clinical and radiologic assessment.

Adult↗
PubMed2002

In vivo effects of the controlled NO donor/scavenger ruthenium cyclam complexes on blood pressure.

Ruthenium(II/III) complexes able to bind and release NO* were tested in vivo, in conscious Wistar rats instrumented for continuous blood pressure (BP) measurement and administration of in bolus injections (5 to 100 nmol/Kg i.v.) of trans-[Ru(II)Cl(NO+)(cyclam)](PF6)2 (cyclam-NO) or sodium nitroprusside (SNP). For normotensive rats, cyclam-NO produced a sustained 10% BP reduction of basal MAP during 7 +/- 0.4 to 11 +/- 0.3 min. In acute hypertensive rats, cyclam-NO produced BP reduction 3-fold larger than in normotensive rats and similar to that of SNP (maximal effect: 41 +/- 1.3 vs. 45 +/- 2.2 mmHg, respectively). However, the duration of the effect of cyclam-NO was 13 to 21-fold longer than that of SNP. The hypotensive effect of cyclam-NO was fully blocked in presence of continuous infusion of a NO* scavenger, carboxy-PTIO (6 mmol/Kg/min), or of the inhibitor of cGMP activation, methylene blue (83 nmol/Kg/min), or of the cyclam-NO precursor, trans-[RuCl(tfins)(cyclam)](tfms) (cyclam-tfms) (500 mmol/Kg/min). The long lasting BP reduction of cyclam-NO can be interpreted in terms of a slower rate of NO* release (k-NO = 2.2 x 10(-3) S(-1) at 35 degrees C) following chemical reduction (E(0') = 0.10 V vs NHE). In summary, cyclam-NO showed an hypotensive effect around 20 times longer than SNP in either normotensive or hypertensive rats, which was completely inhibited by methylene blue or carboxy-PTIO. Continuous infusion of cyclam-tfms completely blocked the hypotensive effect of cyclam-NO by scavenging the NO* released by the reduced cyclam-NO.

Animals↗
PubMed2002

A descriptive study of randomized trials of treatments for childhood acute lymphoblastic leukaemia.

This report presents a historical and descriptive account of randomized trials in childhood leukaemia since the earliest such studies in the 1960s. It focuses on trials that began before 1988, making use of the register of trials developed for a systematic review of treatments for acute lymphoblastic leukaemia in children. The number of randomized trials starting each year increased from one or two in the 1960s to an annual average of five or six in the 1980s. However trials remained relatively small, with more than half of all randomizations accruing less than 200 patients and only five having more than 1000. Most trials were published more than once.

Adolescent↗