To understand the structure-function relationship in the postinfarcted myocardium in rabbits, we induced cardiac ischemia by ligating the left circumflex coronary artery. Sham controls underwent ...thoracotomy only. At 7 and 30 d after ligation, cardiac MRI was conducted by using
pulse-oxymetry-gated cine acquisition to provide complete phases of the heartbeat. The rabbits were anesthetized under 1.5% isoflurane ventilation, and ultrafast techniques made breath-hold 3D coverage in different cardiac axes feasible. Viability imaging was performed after intravenous
injection of 0.15 mmol/kg gadolinium to assess the extent of infarction. Data (n ≥ 6) are presented as mean ± SEM and analyzed by ANOVA and ANCOVA. In postligation rabbits, end-systolic (mean ± SEM, 2.3 ± 0.3 mL) and end-diastolic (4.2 ± 0.4 mL) volumes
were increased compared with preligation values (end-systolic, 1.1 ± 0.1 mL; end-diastolic, 2.98 ± 0.2 mL). Ejection fraction was influenced adversely by the presence of scar tissue at both 7 and 30 d after ligation and apparently nonlinear with the heart rate. Cardiac force
was increased in the basal region in both end-systole and end-diastole in postligation hearts but progressively decreased toward the apex. Late gadolinium enhancement delineated 15.2 ± 5.8% myocardial infarction at 7 d after ligation and 14.5 ± 5.8% at 30 d, with limited wall
motion and wall thinness. Compensatory wall thickening was present in the basal region when compared with that in preligation hearts. MRI offers detailed spatial resolution and tissue characterization after myocardial infarction.
Eighty-eight patients with pretibial lacerations were entered into a study to analyze bacteriological and wound-healing profiles. Fifty-four patients were followed to complete wound healing. A ...complete photographic record of wounds from time of presentation to healing was available for analysis in 49 of these patients. Staphylococcus aureus was the most common pathogen, but the correlation between clinical wound infection and growth of pathogenic bacteria was poor. Flucloxacillin alone was found to be significantly more effective in controlling wound infection than in combination with metronidazole. Computerized image analysis of the photographic records was performed. There was no significant difference in the healing times of the various classic surgical wound types, and image analysis confirmed that the rates of wound healing were generally similar in all the types of pretibial wounds.
Three‐dimensional fast spin‐echo (3DFSE) techniques are promising for black‐blood imaging of cerebral vessels. In this study, flow‐related signal dephasing was demonstrated as the primary mechanism ...for blood signal attenuation. Parameter optimization of TR (1500 to 3000 ms), receiver bandwidth (25 to 31.25 kHz), effective TE (25.7 to 30.1 ms), and ETL (7 to 8) was accomplished by making measurements of vessel‐totissue contrast‐to‐noise ratios on vessels. A comparison of high‐resolution 3DFSE and 3DTOF magnetic resonance angiography demonstrated that 3DFSE can generate images with equivalent or better small vessel detail than conventional techniques. 3DFSE black‐blood techniques may provide improved sensitivity of small arteries and veins with slow or in‐plane flow and immunity to flow‐related distortions. Future studies with optimized parameters will determine the clinical efficacy of this technique.
In this study, the problem of small vessel visualization in magnetic resonance angiography is addressed. The loss of vessel contrast due to slow flow‐related signal saturation can be compensated by ...the T1 reduction obtained from the use of an MR contrast agent, such as Gd‐DTPA. The vesselfbackground signal‐difference‐to‐noise ratio (SDNR) is shown to strongly depend on the imaging parameters, as well as on the time course of the blood T1 values obtained from the contrast injection. Specifically, it was found that vessel SDNR increases almost linearly with TR, if the sampling bandwidth is reduced proportionately.
Recent efforts to develop a new power transformer incorporating a novel wire core configuration have required that core magnetic flux and power loss be estimated during the development process. In ...this work, an innovative core concept was considered using commercial finite element simulation software, with core loss results shown to be comparable to measurements on a standard 10 kVA design. The results of this analysis demonstrate the possibility of performing the standard no load transformer test in a virtual environment early in the design process, which should aid in predicting the performance of this and other new configurations under various load conditions.
Seventy-eight patients have been treated on a Phase I trial using continuous infusion etanidazole while undergoing brachytherapy for locally advanced tumors. There were two sequential schemata, the ...first treated 63 patients with doses ranging from 8-23 g/m2 over 48 hr and the second treated 15 patients with doses ranging from 20-23 g/m2 over 96 hr. The tumor sites were: brain (n = 42), cervix (n = 22), and breast (n = 14). Patients received a loading dose of etanidazole of 2 g/m2 followed by a continuous infusion for a total of 48 or 96 hr while radioactive implants were in place. Of the 63 patients in the 48-hr study, 52 were entered at doses of less than or equal to 21 g/m2 and there were no definite neuropathies but two patients with the cramping/arthralgia syndrome. Of the 11 patients entered at 22-23 g/m2, 1 patient had symptoms of peripheral neuropathy (Grade II) and 6 had the cramping/arthralgia syndrome. This is a new syndrome, distinct from the peripheral neuropathy, characterized by transient alterations in sensations consisting of cramping, arthralgias, or tingling that resolved completely at intervals varying from a few hours to about 1 week post-treatment. The cramping/arthralgia syndrome limited dose escalation; therefore, the maximum tolerated dose over 48 hr was determined to be 20-21 g/m2. The 96-hr infusion was limited to patients with recurrent gliomas undergoing stereotactic implantation. To date, 15 patients have been treated with doses of 20-23 g/m2. No toxicity was encountered at doses less than or equal to 22 g/m2. At 23 g/m2, one patient developed Grade III neuropathy and three patients had mild cramping/arthralgia syndrome, for whom the drug was discontinued. Therefore, it appears the maximum tolerated dose at 96 hr will be approximately 23 g/m2, which is 10-15% higher than for the 48-hr infusion.
A UK Pandemic Influenza Contingency Plan was developed in 2006 but little research has since been carried out as to how ethically acceptable it will be to society. A survey containing two ...hypothetical scenarios was distributed to 1,018 hospital staff. The survey considered their attitudes to the professional and ethical responsibilities of healthcare workers, and to resource allocation on the intensive care unit (ICU). Of those distributed, 406 (40%) surveys were returned. During a pandemic, 320 (79%) healthcare professionals would continue to work and 339 (83%) felt it would be unprofessional for doctors to leave work. Only 218 (54%) chose the same patient for the last ICU bed. Most staff surveyed felt they should (professionally) and would (voluntarily) work during a pandemic despite high personal risk. A wide diversity of opinion existed regarding resource allocation of ICU beds. These ethical issues require open debate to ensure UK pandemic plans are ethically acceptable and practically applicable.
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