Postbiopsy renal transplant arteriovenous fistulas: color Doppler US characteristics

Color Doppler ultrasound (US) with point-spectral analysis was performed on eight patients with postbiopsy renal transplant arteriovenous fistulas. Waveform analysis of the supplying artery documented decreased resistive indices in all cases and increased flow velocities in seven. The peak-systolic flow velocity in the arteries supplying the fistulas ranged from 55 to 180 cm/sec (mean, 92 cm/sec), while the range in normal arteries was 20-52 cm/sec (mean, 32 cm/sec). The resistive indices of the arteries supplying the fistulas ranged from 0.31 to 0.50 (mean, 0.45), while the resistive indices of the normal arteries ranged from 0.60 to 0.92 (mean, 0.74). Arterialization of the venous waveform from the draining vein was also documented in all cases. In six cases, the increased flow velocities resulted in increased color saturation toward white in the supplying artery (n = 2) or in both the artery and the draining vein (n = 4), which was detectable on the realtime image. In six cases, flow turbulence resulted in localized tissue vibration, which appeared as random color assignment in extravascular renal parenchyma adjacent to the fistula. Knowledge of these imaging and Doppler characteristics should aid in the identification of renal transplant arteriovenous fistulas with color Doppler US.     

Platelet-derived collagenase inhibitor: characterization and subcellular localization.

Purified human platelets were found to contain a collagenase inhibitor that is immunologically, functionally, and chromatographically identical to that produced by human skin fibroblasts. None of the other formed elements of the blood (erythrocytes, granulocytes, mononuclear cells) possessed detectable quantities of this protein. Virtually all the collagenase inhibitor contained within platelets was released following platelet activation with thrombin. Similarly, platelet activation accompanying blood clotting also resulted in the release of this protein, the ratio of plasma to serum inhibitor levels being approximately equal to 0.5. When platelets were subjected to subcellular fractionation, essentially all of the platelet-associated collagenase inhibitor was found to be located in the alpha-granule. Studies with radiolabeled inhibitor failed to detect uptake of inhibitor by platelets. Furthermore, immunologically reactive protein of similar quantity to that found in platelets was identified in human megakaryocyte lysates. Thus, the data suggest that the collagenase inhibitor is endogenously produced and stored within platelet alpha-granules. The platelet-derived collagenase inhibitor was antigenically identical to the collagenase inhibitor from human skin fibroblasts in double immunodiffusion and, like its fibroblast counterpart, inhibited collagenase on a 1:1 stoichiometric basis. When subjected to several of the chromatographic procedures utilized to purify the fibroblast protein, the platelet inhibitor behaved in an indistinguishable manner. Platelet factor 4, previously reported to be a collagenase inhibitor, was found to be immunologically unrelated to the platelet-derived collagenase inhibitor. Furthermore, platelet factor 4 displayed no collagenase inhibitory activity. Although the function of platelet-derived collagenase inhibitor is unknown, such a protein released by activated platelets may serve to regulate collagen turnover during the early stages of the inflammatory process.     

Use of a 585 nm Pulsed Dye Laser for the Treatment of Morphea

INTRODUCTION: The clinical presentation of morphea varies from localized plaques to generalized eruptions. Its cause remains unknown and medical treatments have often proved unsatisfactory. Studies have previously shown that improvement of hypertrophic scars and fibrotic skin can be achieved with the use of a 585 nm pulsed dye laser (PDL). METHODS: A case of plaque-type morphea was treated with 585 nm pulsed dye laser irradiation at an average fluence of 5.0 J/cm2 at bimonthly time intervals. RESULTS: Marked clinical improvement as evidenced by improved pliability and skin coloration was seen after 4 successive PDL treatments. No side effects or complications were encountered. CONCLUSION: Pulsed dye laser therapy is a viable treatment option for morphea. The mechanism of its effect in this condition remains unknown.     

Intentional internal iliac artery occlusion to facilitate endovascular repair of aortoiliac aneurysms

PURPOSE: The safety of intentional occlusion of patent internal iliac arteries (IIAs) to facilitate the endovascular repair of aortoiliac artery aneurysms (abdominal aortic aneurysms [AAAs] and iliac aneurysms [IAs]) was evaluated. METHODS: We analyzed the techniques and clinical sequelae of selective occlusion of one or both IIAs in 103 patients and correlated these findings with the results of preoperative angiograms to identify vascular anatomy that may predict postoperative pelvic ischemia. To quantify the clinical presentation of pelvic ischemia, we developed these criteria: class 0, no symptoms; class I, nonlimiting claudication with exercise; class II, new onset impotence, with or without moderate to severe buttock pain, leading to physical limitation with exercise; class III, buttock rest pain, colonic ischemia, or both. IIA occlusion was achieved in 100% of the patients by means of either catheter-directed embolization or orificial coverage with a stent-graft. No patient in this study had angiographic evidence of significant visceral occlusive disease before the procedure. Sixty-four patients had isolated AAAs, 23 patients had AAAs and IAs, and 16 patients had isolated IAs. Ninety-two patients had one IIA selectively occluded, and 11 patients had both IIAs selectively occluded. RESULTS: After IIA occlusion, 12 patients were categorized in class I, 9 patients were categorized in class II, and 1 patient was categorized in class III, for a total of 22 patients (21%) with pelvic ischemia. Sixteen (17%) of 92 patients had unilateral IIA occlusions, and six (17%) of 11 patients had bilateral IIA occlusions. Five patients in class I improved and had no symptoms within 1 year, and one patient in class II was downgraded to class I because of improved symptoms. Two unique preoperative angiographic findings were identified in the remaining 16 patients (16%) with chronic pelvic claudication: (1) stenosis of the remaining IIA origin (> 70%) with nonopacification of more than three of the six IIA branches (63%); and (2) small caliber, diseased or absent medial and lateral femoral circumflex arteries ipsilateral to the side of the IIA occlusion (25%). One patient with class III ischemia died of cardiovascular collapse associated with colon infarction caused by either acute ischemia or particulate embolization. CONCLUSION: The incidence of pelvic ischemia after IIA occlusion is 20% immediately after endovascular aortoiliac aneurysm repair. A total of 25% of patients had no symptoms within 1 year. Two preoperative radiologic findings may help identify patients who are at risk for pelvic ischemia: stenosis of the patent IIA and disease deep femoral ascending branches ipsilateral to the occluded IIA. The risk of colon ischemia appears to be small after selective IIA occlusion to facilitate endovascular AAA repair.     

Prevalence of polyps greater than 9 mm in a consortium of diverse clinical practice settings in the United States.

BACKGROUND & AIMS: Colonoscopy is often performed with the goal of identification of patients with serious colon neoplasia. We determined the prevalence of colon masses or polyps greater than 9 mm on the basis of age, gender, race, and procedure indication in diverse clinical practice settings and compared occurrence in patients receiving colonoscopy for screening, surveillance, or evaluation of symptoms. METHODS: We obtained patient demographics, procedure indication, and endoscopic findings from colonoscopy reports in the Clinical Outcomes Research Initiative data repository, which receives endoscopy reports from 73 diverse practice sites in the United States. A multivariate model was developed to measure risk variables for a mass or polyps >9 mm. Absolute risk was calculated in the model on the basis of the number needed to endoscope (NNE) to identify 1 patient with a mass or polyp >9 mm. RESULTS: From 2000-2002, colonoscopies in 141,413 unique patients were analyzed. Sixty-nine percent of the reports came from private practice (nonacademic) settings. Increasing age, male gender, and black race were associated with increased risk of mass or polyps >9 mm. In the 50- to 59-year-old average-risk group, 28 women and 18 men would need to have screening colonoscopy to identify 1 patient with a mass/polyp >9 mm. Patients with positive fecal occult blood test results, hematochezia, and anemia had lower NNE, whereas men older than 60 years receiving adenoma surveillance and patients with irritable bowel symptoms had similar NNE compared with average-risk subjects. CONCLUSIONS: The prevalence of a colon lesion >9 mm varies on the basis of age, gender, race, and procedure indication. Understanding utilization and outcomes can lead to more optimal use of colonoscopy.