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Biomedical subjects

D J Cook

Publications and source records attributed to D J Cook.

At least 307 records · Page 17Linked to original sources

Can serial scintigraphic studies detect delayed fracture union in man?

The uptake of the bone-seeking tracer technetium-99m-methylenediphosphonate increases following bone fracture as bone healing occurs. To investigate the pattern of change in normal healing and compare it with delayed union and nonunion, an analysis of automated computer profiles was carried out on serial scan data for 22 patients. The type of fracture (simple, comminuted, etc.) influenced the appearance of the activity profile; however, no significant differences in the patterns of change were noted between normal healing and delayed or non-union.

Adolescent↗

Technetium-99m calcium phytate--optimization of calcium content for liver and spleen scintigraphy: concise communication.

The addition of ionic calcium to technetium-99m stannous phytate produced an agent with improved splenic uptake. In a series of patients, it was found that molar ratios of 2:1 and 3:1 produced scans of optimal diagnostic quality. Studies in mice showed dose-related changes in the biodistribution. Electron microscopy demonstrated that the addition of calcium produced progressive aggregation of the colloid as the molar ratio was increased. Chemical analysis of sodium phytate was essential to obtain accurate ratios.

Animals↗

Thallium-201 for myocardial imaging: appearance of the normal heart.

Thallium-201 myocardial perfusion images were obtained from 13 healthy adults after tracer administration both at rest and at maximal stress. On the rest-injected scan, tracer was seen in left ventricular myocardium, liver, and spleen. In two subjects with resting tachycardia, the right ventricular myocardium was slightly visualized after tracer injection at rest. When tracer was administered at stress, the left ventricular activity was more nearly homogeneous and the left ventricle was better defined on the scan. The left-ventricle-to-lung-background activity ratio increased from 2.4 at rest to 3.4 at stress. The right ventricular myocardium was seen on the stress-injected scan. Phantom studies, performed to define the optimum position for visualization of lesions, showed that small lesions were best defined when seen either en face or in tangent. Scans should be performed at stress whenever possible and multiple views are essential.

Adult↗

Mortality and prehospital thrombolysis for acute myocardial infarction: A meta-analysis.

CONTEXT: Early administration of thrombolysis for acute myocardial infarction (AMI) may improve survival if safely and appropriately delivered. No systematic reviews that have comprehensively examined this topic exist in the literature. OBJECTIVE: To perform a meta-analysis of randomized controlled trials of prehospital vs in-hospital thrombolysis for AMI measuring in-hospital mortality. DATA SOURCES: The Cochrane search strategy was used to search MEDLINE, EMBASE, and the Science Citation Index (1982-1999); Dissertation Abstracts (1987-1999); and Current Contents (1994-1999) for the terms thrombolysis, thrombolysis therapy, prehospital, and acute myocardial infarction. In addition, text and journal article bibliographies were hand searched, the National Institutes of Health Web site was reviewed, and primary authors and thrombolytic drug manufacturers were contacted for unpublished studies. STUDY SELECTION: Randomized controlled trials of prehospital vs in-hospital thrombolysis for AMI measuring all-cause hospital mortality were included. Two authors independently reviewed 175 citations by title, abstract, or complete article. After exclusion of 30 duplicate citations, 145 studies remained, of which 6 studies and 3 follow-up studies met the inclusion criteria. DATA EXTRACTION: Independent data abstraction by 2 reviewers blinded to the journal, title, and author was confirmed by consensus. Trial quality was independently assessed by 2 other coauthors, blinded to the author, title, journal, introduction, and discussion. DATA SYNTHESIS: The results of the 6 randomized trials (n=6434) were pooled and indicated significantly decreased all-cause hospital mortality among patients treated with prehospital thrombolysis compared with in-hospital thrombolysis (odds ratio, 0.83; 95% confidence interval, 0.70-0.98). Results were similar regardless of trial quality or training and experience of the provider. Estimated (SE) time to thrombolysis was 104 (7) minutes for the prehospital group and 162 (16) minutes for the in-hospital thrombolysis group (P=.007). CONCLUSIONS: Our meta-analysis suggests that prehospital thrombolysis for AMI significantly decreases the time to thrombolysis and all-cause hospital mortality. JAMA. 2000;283:2686-2692.

Emergency Medical Services↗