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Biomedical subjects

Charles A James

Publications and source records attributed to Charles A James.

5 recordsLinked to original sources

Microbubble-augmented ultrasound declotting of thrombosed arteriovenous dialysis grafts in dogs.

PURPOSE: Transcutaneous low-frequency ultrasound (LFUS) can effectively lyse clots in the presence of microbubbles. This study was designed to test the commercially available human albumin microspheres injectable suspension octafluoropropane formulation, Optison, to establish efficacy and assess US parameters of intensity and wave modes in a canine model of a thrombosed arteriovenous (dialysis) graft. MATERIALS AND METHODS: Arteriovenous grafts in five dogs were cannulated, temporarily ligated, and thrombosed. Different declotting techniques were randomized to treat nine groups. Control groups involved direct saline (4.5 mL) clot injection in 0.5-1.0-mL increments. One group underwent peripheral intravenous microbubble injection (13.5 mL). Six groups underwent direct incremental clot injection of 4.5 mL of microspheres with LFUS for 30 minutes in 3-5-minute increments with use of various intensity settings in continuous-wave and pulsed-wave (PW) modes. At each increment, angiography was used to grade flow, declotting, and overall success. RESULTS: One hundred four procedures showed success in all 24 high-intensity PW modes (1.2-2.0 W/cm(2)); only one of 20 control experiments was successful (P <.0001). Medium-intensity modes yielded intermediate success rates. Lowest-intensity direct-injection groups and intravenous and control groups ranked lower. Results at 30 minutes were better than at 15 minutes (P <.0001). CONCLUSIONS: LFUS with direct injection of microbubbles is effective in lysing moderate-sized clots and recanalizing thrombosed arteriovenous grafts. It best succeeds at the higher range of intensity settings tested in PW mode. Further development is justified.

Albumins↗

Digital radiography in the diagnosis of Toddler's fracture.

BACKGROUND: The objective of this study was to evaluate the accuracy of digital imaging in the diagnosis of toddler's fractures. METHODS: Medical records for a 9.4-year period were reviewed to locate children whose initial radiographs were interpreted as normal by a pediatric radiologist and whose subsequent bone scans or follow-up radiographs showed toddler's fractures. Radiographs from these children (ie, positive controls) and from children without toddler's fractures (ie, negative controls) were digitized to create a film bank that was reviewed by a panel of 14 physicians with various medical backgrounds. Medical records were reviewed for demographic information, findings on history and physical examination, and radiographic and laboratory tests. RESULTS: Pediatric radiology physicians correctly diagnosed 73.2 +/- 5.4% of the digitized images, as compared with pediatric emergency physicians, 66.7 +/- 6.5% and residents/fellows, 57.1 +/- 6.9%. CONCLUSION: Digitized images may be helpful in evaluating limping children with suspected toddler's fractures, possibly eliminating the need for further diagnostic studies.

Child, Preschool↗

Vascular tumors of infancy and childhood: beyond capillary hemangioma.

Vascular tumors of infancy and childhood represent a number of clinicopathologically distinct entities for which precise histopathological diagnosis is often essential in determining effective therapeutic approach. Unfortunately, pathologists and clinicians alike have traditionally tended to lump these tumors, in addition to small vessel vascular malformations, under overly generic terms like capillary hemangioma that do little, if anything, to guide proper clinical management. In the last decade this nosologic oversimplification has begun to wane as important new diagnostic tools and better understanding of etiology have evolved, facilitated by international recognition of the need for a multidisciplinary approach in dealing with these perplexing and often clinically devastating lesions. This article provides a brief historical perspective on this progress, and then focuses on the current clinical, histological, and immunophenotypical features that distinguish the major types of vascular tumors of infancy and childhood, also reviewing new evidence regarding their mechanisms of pathogenesis.

Blood Vessels↗

Popliteal artery disease: diagnosis and treatment.

The popliteal artery is a relatively short vascular segment but is affected by a unique set of pathologic conditions. These conditions, which may be common throughout the arterial system or exclusive to the popliteal artery, include atherosclerosis, popliteal artery aneurysm, arterial embolus, trauma, popliteal artery entrapment syndrome, and cystic adventitial disease. The clinical manifestations, imaging appearances, and treatment options associated with these pathologic conditions differ significantly. Consequently, the radiologist should be familiar with these conditions to direct imaging for accurate diagnosis and treatment and to prevent loss of limb.

Adolescent↗