Biomedical subjects
Publications and source records attributed to P M Castelli.
The currently prevailing trends in industrial contrast agent research for MRI are discussed. Specific mention is made of contrast agents for liver imaging using both static and delayed procedures, of the potential for blood pool agents and the form such agents may take, and of the ultimate challenge for contrast agent R&D: tissue-targeting in a wider sense to both normal and pathologic tissues.
RATIONALE AND OBJECTIVES: The authors assess the effect of weak protein binding on the efficacy of gadolinium chelates as contrast agents for magnetic resonance imaging (MRI). METHODS: Chelates with no (gadopentetate dimeglumine), weak (gadobenate dimeglumine), and strong (B-21326/7) protein binding were compared by in vitro MRI at 2T (spin echo [SE]: repetition time [TR]/echo time [TE] 350/8 mseconds) on solutions in 0.5 mM bovine serum albumin and in rat whole blood, and by in vivo MRI at 2T on rat models of brain tumors (SE TR/TE 350/10 mseconds) and of focal blood-brain barrier disruption (SE TR/TE 400/15 mseconds) after injection of MPP+. Relaxation rate enhancement in the blood of normal rabbits was measured in vivo after administration of contrast agents using IR-Snapshot FLASH. RESULTS: Signal intensity enhancement measured in vitro for whole rat blood 0.1 mM in gadobenate was 142% relative to the same concentration of gadopentetate. Peak signal intensity enhancement in brain tumors was 87% +/- 8% and 64% +/- 5% after 0.1 mmol/kg intravenous administration of gadobenate and gadopentetate, respectively; in MPP+ lesions, the peak signal intensity enhancement was 22% +/- 9%, 32% +/- 7%, and 64% +/- 14% after 0.2 mmol/kg intravenous of gadopentetate, gadobenate, and B-21326/7, respectively. In rabbits, the relaxation enhancement of blood 5 minutes after B-21326/7 and gadobenate administration was 323% and 182%, respectively, relative to the same dose (0.1 mmol/kg intravenous) of gadopentetate. CONCLUSIONS: Weak protein binding can substantially increase the efficacy of gadolinium chelates as general purpose contrast agents for MRI.
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We tested 276 sera from 18 free-ranging black-tailed and mule deer (Odocoileus hemionus) herds in California (USA) collected from 1987 to 1991 in five biogeographical habitat types, for antibodies against eight infectious disease agents. Overall antibody prevalence was 56% for Anaplasma marginale, 31% for Borrelia burgdorferi, 16% for bluetongue virus serotype 17, 15% for epizootic hemorrhagic disease virus, 7% for Coxiella burnetii and Toxoplasma gondii, respectively, and 0% for bovine leukosis virus and caprine arthritis/encephalitis virus, respectively. Antibodies against Lyme borreliosis and anaplasmosis were found in deer throughout California, but antibodies against bluetongue and epizootic hemorrhagic disease were most prevalent in deer from southern California.
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Fifty-six femoral non infected anastomotic false aneurysms (FAAs) were observed in 49 patients admitted to the Institute of Vascular Surgery, University of Milan, from 1975 to 1988; in 6 patients they were bilateral. These aneurysms developed after primary revascularization procedures at a mean interval of 66 months (range 12 to 156 months); one recurred after reparative surgery. Forty-four FAAs (78.6%) were asymptomatic, whereas 3 (5.3%) were complicated by acute expansion and 9 (16.1%) by thrombosis. Host vessel degeneration was the cause of aneurysm formation in most cases. A history of hypertension was present in 30% of the patients. All anastomotic aneurysms were operated upon except for one small aneurysm that was asymptomatic. In 5 patients aneurysm resection was carried out on both sides. The surgical technique was endoaneurysmectomy in all the cases with insertion of an interposition graft in 48 cases, a fabric patch in 2 cases and prosthesis re-anastomosis in 5 cases. One case of peripheral embolization occurring in the early postoperative period was successfully treated and there was no operative mortality. In our opinion elective repair of these aneurysms should be recommended whenever possible because of their propensity to develop serious complications and the operative morbidity is low.
Late occlusion of an aortofemoral bypass graft is usually caused by fibrointimal hyperplasia or progressive atherosclerosis. Several surgical approaches have been advocated in order to minimize the operative risk, to correct the impaired inflow and to provide a satisfactory outflow. In the last 16 years, in the Institute of Vascular Surgery and Angiology of the University of Milan, we have operated upon 182 consecutive thrombosed grafts. Inflow was restored by performing a graft limb thrombectomy using a Fogarty balloon catheter and simultaneously employing an endarterectomy ring stripper to dislodge tenaciously adherent fibrinous material and thrombotic plug. As the superficial femoral artery was generally occluded, usually a good outflow was achieved by profundaplasty in 101 cases (55.5%) or direct bypass (interposition graft), to a more distal segment of the profunda femoris artery in 55 cases (30.2%). Concomitant popliteal or tibial revascularization was done in the remaining 26 cases (14.3%) when pre-operative or intra-operative findings suggested an inadequate collateral network through the profunda femoris artery. Early re-occlusion, which occurred in 14 cases (7.6%), generally due to insufficient outflow, was corrected by additional intervention in 7 cases (3.8%), while 7 legs were amputated for extensive atherosclerotic disease. Six patients died giving a mortality rate of 3.3%. This low rate in a high risk population is probably related to our policy of operating under loco-regional anaesthesia. Long term results, with a patency rate of 62.0% at 3 years and 60.2% at 5 years (life table method), prove that this operation is a durable procedure for correction of graft limb thrombosis.
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