Fracture of a covered stent used for pseudoaneurysm exclusion in a prosthetic femoro-infrapopliteal bypass

PURPOSE: To present a case of fracture in a stent-graft used for exclusion of a pseudoaneurysm in a prosthetic femoro-infrapopliteal bypass. CASE REPORT: A Hemobahn stent-graft was inserted into a Dacron femoro-infrapopliteal bypass to avoid repeat surgery for a recurrent distal anastomotic pseudoaneurysm that had been excluded 2 years earlier by a Dacron interposition graft in a 69-year-old woman. Three months after stent-graft implantation, the patient complained of pain around the left knee; plain radiography showed stent fractures at 2 sites coinciding with the proximal and distal anastomoses of the interposition graft, and ultrasonography detected a new pseudoaneurysm at the distal anastomosis. The stent-graft was explanted and the pseudoaneurysm excluded with a new interposition graft. CONCLUSION: Although some stents have high flexibility and radial strength that make them suitable for use in periarticular vessels, interventionists should take into account the possibility of stent fracture when weighing the treatment options.     

The treatment of malignant histiocytosis

Twenty-four consecutive cases of malignant histiocytosis (MH) treated at Stanford Medical Center between 1973 and 1983 have been reviewed. Most patients presented with systemic symptoms (91%) and advanced disease (stage IV, 80%). Multiple organ involvement was common. In six cases, pathologic tissue was further characterized by frozen section immune histochemistry, using a panel of monoclonal antibodies known to react with monocytes and macrophages, as well as a variety of hematopoietic cells. One case expressed a mature monocyte/macrophage phenotype; three cases were considered null cell or primitive lesions; and two cases were identified as probable T cell lymphomas. Seven patients underwent splenectomy. Two patients died prior to any treatment. Twenty-two patients were treated with CHOP (cyclophosphamide, Adriamycin, vincristine, prednisone) +/- bleomycin (B), +/- midcycle high-dose methotrexate (HD-MTX) with leucovorin rescue. Seven patients received prophylactic intrathecal MTX. Of 22 evaluable patients, there was a 68% complete response rate (CR), a 23% partial response rate (PR), and a 9% no response rate (NR). Median duration of CR was 30+ months; median duration of PR was 2.4 months. Median survival for patients attaining a CR has not been reached v 3 months for the PR and NR groups. For all 24 patients, median survival was 2 years, with a 5-year actuarial survival of 40%. Multivariate analysis revealed that a platelet count less than 150,000 (P Cox = .005) and the dose of drug delivered (P Cox = .057) were the most important prognostic factors. Prophylactic intrathecal MTX therapy and splenectomy did not influence survival. Although MH is an aggressive disease with a poor prognosis, it is potentially curable. Systematic and aggressive treatment should further improve the outcome.     

Antioxidative treatment inhibits the release of thrombogenic tissue factor from irradiation- and cytokine-induced endothelial cells

OBJECTIVES: The aim of this study was to investigate the effect of the antioxidants pyrrolidine dithiocarbamate (PDTC) and N-acetylcysteine (NAC) on the ionizing radiation (IR)- and tumor necrosis factor-alpha (TNF-alpha) induced tissue factor (TF) expression and its release from human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were irradiated with a single dose of either 5 Gy or 10 Gy and stimulated with TNF-alpha (10 ng/mL) in the presence or absence of PDTC and NAC, respectively. Quantitative real-time PCR, ELISA, and TF activity measurements were performed, including TF activity in the supernatant. Apoptosis was detected by flow cytometric active caspase-3 measurement and formation of reactive oxygen species (ROS) by chemiluminescence. RESULTS: We demonstrated a thus far uninvestigated persistent induction of TF expression in HUVECs after treatment with IR and TNF-alpha. Combined stimulation with IR and TNF-alpha led to an immense shedding of microparticle-associated TF which was positively correlated with apoptosis and ROS formation. Antioxidative pre-treatment reduced not only apoptosis and ROS formation, but also the release of thrombogenic microparticles. CONCLUSIONS: Antioxidative treatment inhibited apoptosis and shedding of microparticles, thereby reducing thrombogenicity. Thus, antioxidants may help to prevent late thrombosis after antiproliferative treatment when used in combination with anticoagulants.     

Quantification of prostate MRSI data by model-based time domain fitting and frequency domain analysis

This paper compares two spectral processing methods for obtaining quantitative measures from in vivo prostate spectra, evaluates their effectiveness, and discusses the necessary modifications for accurate results. A frequency domain analysis (FDA) method based on peak integration was compared with a time domain fitting (TDF) method, a model-based nonlinear least squares fitting algorithm. The accuracy of both methods at estimating the choline + creatine + polyamines to citrate ratio (CCP:C) was tested using Monte Carlo simulations, empirical phantom MRSI data and in vivo MRSI data. The paper discusses the different approaches employed to achieve the quantification of the overlapping choline, creatine and polyamine resonances. Monte Carlo simulations showed induced biases on the estimated CCP:C ratios. Both methods were successful in identifying tumor tissue, provided that the CCP:C ratio was greater than a given (normal) threshold. Both methods predicted the same voxel condition in 94% of the in vivo voxels (68 out of 72). Both TDF and FDA methods had the ability to identify malignant voxels in an artifact-free case study using the estimated CCP:C ratio. Comparing the ratios estimated by the TDF and the FDA, the methods predicted the same spectrum type in 17 out of 18 voxels of the in vivo case study (94.4%).     

Complex porcine model of atherosclerosis: Induction of early coronary lesions after long-term hyperlipidemia without sustained hyperglycemia

BACKGROUND:

The incidence of coronary artery disease (CAD) is still increasing in industrialized countries and it is even higher in diabetic patients. For experimental studies investigating the pathophysiology of CAD, the use of an animal model comparable with the pathological situation in patients is crucial.

OBJECTIVE:

To develop a model of advanced coronary atherosclerosis with induction of hyperlipidemia and hyperglycemia in domestic pigs.

METHODS:

Six pigs were fed a standard pig chow (controls), two were fed a 2% cholesterol and 17% coconut fat diet (Chol group), and two pigs received a 4% cholesterol and 17% coconut fat diet combined with streptozotocin (STZ) injections to induce diabetes (High Chol+STZ group). Serum lipid and plasma glucose values were analyzed, and histochemical staining for morphometric analysis and immunohistochemistry were performed.

RESULTS:

Pigs on the hyperlipidemic diet had elevated mean (± SD) serum lipid levels (total cholesterol 5.05±1.45 mmol/L [Chol] and 5.03±2.41 mmol/L [High Chol+STZ] versus 2.09±0.23 mmol/L [controls]). Histopathological evaluation revealed an initial stage of coronary atherosclerosis. None of the STZ-treated pigs showed a sustained elevation of plasma glucose (mean glucose before STZ injection was 5.11±0.94 mmol/L and thereafter was 6.03±2.39 mmol/L) or a decline in pancreatic beta cells.

CONCLUSIONS:

The current data suggest that the domestic porcine model is not suitable to create severe CAD using an atherogenic diet in combination with STZ injections for experimental interventional vascular research. This may be due to different STZ sensitivities among species. However, hyperlipidemia induced early pathological lesions in coronary arteries resembling initial stages of atherosclerosis without severe luminal narrowing.     

Sterilisation von Instrumenten in kochenden Desinfektionslösungen (Baktol,Carvasept, Sagrotan und Zephirol)

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