Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Calcinosis at the site of leakage from extravasation of calcium disodium edetate intravenous chelator therapy in a child with lead poisoning

Painful calcinosis appeared at the wrist of an eight-year-old girl with lead poisoning. Careful history revealed that calcification occurred at the site of previous extravasation of calcium disodium edetate (EDTA) used in chelation therapy. Light microscopic, ultrastructural, electron activation, and X-ray diffraction studies demonstrated apatites with some suggestion of an admixture of octacalcium phosphate.     

AlphaV beta3 (αvβ3) integrin inhibition reduces leukocyte–endothelium interaction in a pressure-induced reperfusion model

The leukocyte-endothelium interaction is known to contribute to reperfusion injury, which is considered to participate in the pathophysiology of pressure ulcers, and integrin alphaV beta3 (alphavbeta3) has been shown to mediate the processes of cellular adhesion in various types of cells. This study aims to clarify leukocyte behavior in our original microcirculatory pressure-induced reperfusion model, which can visualize the microcirculation in vivo. We also estimated the effect of alphavbeta3 integrin inhibition on the reduction of the leukocyte-endothelium interaction. Mice with dorsal skinfold chambers were divided into three groups: the baseline group (n=6), in which animals received no compression; the compression-reperfusion group (n=6), in which animals underwent 2-hour compression of the dorsal skin, followed by release, and the inhibitor-treated group (n=7), in which an alphavbeta3 inhibitor, CP4715, was administered in addition to the compression-release procedure. Staining with rhodamine 6G quantitatively visualized leukocyte behavior under the intravital fluorescent microscope. Compression-reperfusion induced a significant increase in rolling, sticking, and extravasation of the leukocytes. Treatment with the inhibitor strikingly reduced leukocyte sticking and extravasation. The present experiment has provided evidence that alphavbeta3 inhibition reduces leukocyte-endothelium interaction in our original pressure-induced reperfusion model.     

Raf-1 kinase,epidermal growth factor receptors,and mutant ras proteins in colonic carcinomas

Epidermal growth factor receptors (EGFR) andras mutations are known to play a significant role in controlling cell growth and tumor promotion. Both of them transmit mitogenic signals to the nucleus by activation of Raf-1 kinase. In this study, the expression of EGFR and mutant Ras proteins, and, for the first time, the expression, phosphorylation and kinase activity of Raf-1 kinase have been determined in paired samples of colorectal cancer and mucosa. The tumor and mucosa samples did not differ significantly with regard to Raf-1 kinase content and activity. A major difference between tumors and mucosa was found, however, in the phosphorylation of Raf-1. Most of the mucosa samples (13/20), but only 1/20 of the cancer samples, contained hyperphosphorylated Raf-1. EGFR were significantly (p=0.0025) decreased in the tumors. The decreased phosphorylation of Raf-1 in colonic carcinomas could be the result of activation of Raf-1 phosphatases or inactivation of kinases phosphorylating Raf-1. New forms of treatment based on EGFR overexpression do not seem to be suitable for the majority of colonic cancers.This work was supported by the state of Baden-Württemberg (Verbundforschungsprojekt: Aufklärung von Mechanismen der Tumorentstehung und Tumorabwehr).     

Analysis of ischemia-reperfusion injury in a microcirculatory model of pressure ulcers

The aim of this study was to establish a pressure ulcer model that visualizes the microcirculation, and to examine the participation of ischemia-reperfusion injury in the pathophysiology of pressure ulcers. An original system composed of a new skin fold chamber and compression device allowed loading quantitative vertical stress to the skin. An intravital microscopic technique enabled direct visualization of the microcirculation in the physiological condition and in response to pressure application. To estimate the effect of ischemia-reperfusion injury, animals were divided into two groups: the compression-release group (n = 8), in which the animals received four cycles of compression-release which consisted of 2 hours of compression followed by 1 hour of pressure release; and the compression alone group (n = 8) in which the animals underwent continuous compression for 8 hours. Functional capillary density was quantified before the compression procedure and on day 1 (35 hours) after the first evaluation. The cyclic compression-release procedure significantly decreased functional capillary density as compared to continuous compression, indicating that in our experimental setting repetition of ischemia-reperfusion cycle more severely damaged the microcirculation than single prolonged ischemic insult. This finding supports the significant contribution of ischemia-reperfusion injury to the pathophysiology of pressure ulcers at the level of dynamic in vivo microcirculation.     

Multidisciplinary preoperative assessment and late function in dysvascular amputees.

During a three-year period, 95 adults were treated by lower-extremity amputations for peripheral vascular insufficiency. A multidisciplinary team for presurgical evaluation determined all to be potentially independent walkers with a prosthesis. Patients were graded for level of independent walking before amputation and again at a minimum two-year follow-up examination using a seven-level functional grading system. Seventy-six of 90 patients (84%) ambulated within one functional level of their preamputation status. This return to preamputation level of function was maintained whether comparing preamputation functional level or surgical amputation level. Prosthetic use increased and the use of walking aids decreased with increased functional ambulation levels, but did not correlate with surgical levels. Peripheral vascular insufficiency patients can maintain walking independence. Multidisciplinary presurgical evaluation helps selection of the amputation level and correct prosthetic limb fitting.     

Poor prognosis in atypical Perthes' disease. Radiographic analysis of 19 hips after 35 years.

We analyzed clinical and radiographic long-term results in 96 patients (106 hips) with Perthes' disease 35 years after nonoperative treatment. 19 hips in 17 patients had early radiographic signs indicating atypically severe course of the disease and poor prognosis. None of them was radiographically good at skeletal maturity; 2 cases were fair and 17 poor. At the final follow-up 12 hips had radiographic arthrosis.     

Balloon dilatation versus surgical revision of infra-inguinal autogenous vein graft stenoses: long-term follow-up

Although infra-inguinal autogenous vein graft stenoses may be treated by balloon dilatation (PTA) or surgical revision, the optimal approach is undefined. Over the last 7 years 24 PTA procedures were performed on 37 vein graft stenoses in 19 grafts. Graft stenoses were diagnosed from 2 to 72 (mean = 17.3) months after implantation. PTA was successfully completed in 23 (96%) of the 24 procedures including 18 (95%) of the primary, and 5 (100%) of the secondary procedures. Recurrent vein graft stenosis or graft thrombosis developed in 12 (67%) grafts from 3 to 47 (mean = 12.5) months after primary PTA. Long-term patency after primary PTA was 69% at 6, 29% at 12, and 22% at 36 months; secondary patency was 81% at 6, 45% at 12, and 27% at 36 months. During the same period vein graft stenosis in 7 fem-pop and 2 fem-tib grafts were surgically revised with an initial success rate of 100%, and 2 (22%) complications. Four (44%) of these grafts occluded from 1-17 (mean 6.2) months after repair, yielding a primary 5-year patency of 62%. Although vein graft stenosis may be safely, effectively, and repeatedly treated with PTA, long-term durability appears to be superior after surgical revision.