Acute intestinal ischemia and infarction remain serious clinical problems despite early operative intervention. An accurate and reproducible method of assessing ischemic tissue is critical to ...determine the precise limits of resection. The purpose of this study was to compare the utility of infrared photoplethysmography, intravenous fluorescein, and Doppler ultrasound in assessing intestinal ischemia in an operative canine model. After five segmental mesenteric arterial ligations in each of six conditioned dogs, the detection threshold for the limits of arterial perfusion of each modality was determined and correlated with the respective histopathologic specimens. Infrared photoplethysmography proved to be 100% sensitive for ischemia when its waveform amplitudes were 50% or greater of matched reference waveforms, whereas both intravenous fluorescein and Doppler ultrasound were 88% sensitive. All were comparably specific. We conclude that infrared photoplethysmography is comparable to intravenous fluorescein and Doppler ultrasound in the assessment of ischemic intestinal segments.
Fiberoptic angioscopy was performed with 2.5- and 3.3-mm angioscopes in 25 arteries and grafts in 19 patients. Radiologically normal and abnormal arteries and anastomotic sites were examined. All ...vessels and grafts were visualized and images of normal arterial wall, subclinical and obstructing atherosclerotic plaque, and suture lines were defined. Unexpected endovascular findings were noted in five patients (26%) and included large amounts of free-floating clot (one patient), atherosclerotic debris (two patients), and membranelike obstructions (two patients). Angioscopy required three to ten minutes and resulted in no complications. Experience with the flexible angioscope indicates that satisfactory visualization and specific recognition of angiographically unsuspected problems can be obtained. The flexible angioscope is faster and appears more etiologically specific than arteriography.
A naturally aspirated Perkins 4-236 engine was compared with a similar turbocharged Perkins engine. The higher pressures and temperatures of a turbocharged engine should make the pyrosynthesis of PAH ...more likely than for a NA engine and this was investigated using the fuel n-alkanes as tracers for the unburnt fuel of the same fuel distillation fraction as the PAH. The results showed that the below C20 the NA and TC survivabilities of fuel n-alkanes onto the particulates were similar at below 0.02%. For higher nalkanes the turbocharger was much more efficient at burning the fuel, with survivabilities of C24 a factor of 10 below the NA results. The higher operating temperatures of the TC engine reduced the UHC emissions and this reduced the higher boiling fraction unburned fuel. In contrast to these results the fuel PAH apparent survivability's were higher, by approximately a factor of 10, for the turbocharged engine for equivalent boiling point compounds in the range C18-C22. Although for both engines less than 1% of the fuel PAH survived, the results possibly indicate some pyrosynthesis of PAH in the turbocharged engine. For the higher molecular weight PAH the survivabilities were similar between the two engines. For both engines fuel PAH was the dominant source of the particulate PAH.
Recent Publications Klee, Victor; Bartle, Robert G.; Pinkham, Roger S. ...
The American mathematical monthly,
11/1/1962, Letnik:
69, Številka:
9
Journal Article
Recent Publications Klee, Victor; Bartle, Robert G.; Pinkham, Roger S. ...
The American mathematical monthly,
11/1962, Letnik:
69, Številka:
9
Journal Article
Book Reviews Burianyk, Natalia; Bartle, John; Daniels, Robert V. ...
Canadian Slavonic Papers: Canadian Contributions to the XII International Congress of Slavists, Kraków, 1998,
19/9/1/, Letnik:
39, Številka:
3-4
Book Review
