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Biomedical subjects

S H Duda

Publications and source records attributed to S H Duda.

At least 19 recordsLinked to original sources
PubMed2005

Drug coated stents for carotid intervention.

Carotid endarterectomy has demonstrated its superiority over medical treatment of symptomatic as well as asymptomatic stenosis of the extracranial carotid artery. Although minimally invasive methods initially failed to produce similar results, stent implantation is becoming an alternative technique for stroke prophylaxis with technical advances, cerebral protection and careful patient selection. Even though restenosis does not seem to be a major limitation compared to coronary interventions, in-stent restenosis might occur more frequently with an increasing number of procedures performed and longer follow-up periods. Drug eluting stents have shown to attenuate this complication. Currently, no clinical data on drug eluting stents in carotid arteries are available. This article discusses the current literature on carotid artery stenting and the potential role of drug eluting stents in this field.

Antineoplastic Agents, Phytogenic↗
PubMed2004

[Liposome-mediated transfection of thrombomodulin in vascular smooth muscle cells--a gene therapy concept to inhibit recurrent stenosis].

PURPOSE: Thrombomodulin (TM), an integral endothelial receptor, is known for its anticoagulant functions. Moreover, there is evidence of growth-modulating effects of this cell surface -protein. The aim of our study was to establish by in vitro transfection a stable cell line of vascular smooth muscle cells with overexpression of TM for further investigations concerning the influence of TM on cellular proliferation and its potential role during the formation of restenosis. METHODS: Aortic smooth muscle cells of the rat were transfected with cDNA of mouse TM or one of its three mutants (M1, M2, M4) by a liposome-mediated technique. The expression of mouse TM mRNA in the selected clones was proven with the help of RT-PCR. Changes of cell proliferation were determined by proliferation kinetics over 24 days. The quantification of the total protein TM was made by Western blots. RESULTS: In 44 of 100 cases the RT-PCR confirmed a successful transfection of mouse-TM. The clones with transfected TM, M1 or M2 showed an inhibited cell growth, whereas M4 demonstrated an increased proliferation compared with controls. The comparison of amounts of total TM with cell growth of individual clones resulted in a negative correlation between proliferation and TM-expression (coefficient of correlation for TM -0.87, for M1 -0.59). CONCLUSIONS: It is possible to reproduce stable cell-lines of vascular smooth muscle cells with overexpression of TM by the presented model of in vitro transfection. Thus, a basis exists for detailed examinations of growth-regulating mechanisms by TM.

Analysis of Variance↗
PubMed2004

[Chemoembolization of hepatocellular carcinomas: which factors determine therapeutic response and survival?].

PURPOSE: To determine independent prognostic factors influencing the survival of patients with hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolization (TACE). MATERIALS AND METHODS: Ninety-one patients with unresectable HCC were treated with 269 repetitive TACE. The dosages of epirubicin (40-60 mg) and ethiodized oil (8-20 ml) were adjusted to tumor size and liver function. The impact of tumor size, macroscopic tumor type, tumor location, portal vein infiltration, capsular infiltration, tumor vascularization, uptake of ethiodized oil within the tumors, Child-Pugh-Class and Okuda-Stage on patient survival were evaluated by means of univariate and multivariate regression analysis. RESULTS: The following independent prognostic factors were found: tumor type (nodular vs. infiltrating, p = 0 008), tumor size (p = 0.01), Child-Pugh-Class (A vs. B; p = 0.02) and grade of tumor vascularization (p = 0.04). In 57 patients with HCC of the nodular type, the median survival time was significant longer than in 32 patients with HCC of the infiltrating type (17.0 months vs. 7.9 months; p < 0.003; 2 tumors could not be classified). The 1-, 2- and 3-year-survival rates were significantly higher in 57 patients with Okuda-Stage I disease, compared to 34 patients with Okuda-Stage II and III disease (73%, 31% and 8% vs. 23%, 6% and 4% p < 0.0001). CONCLUSIONS: Tumor type, tumor size and grade of liver cirrhosis have an independent impact on prognosis of patients with HCC treated by TACE. An appropriate selection of patients is necessary to improve patients survival.

Adult↗
PubMed2004

[Dose dependent effects of the combined beta-gamma-emitter 188Rhenium on the growth of human vessel wall cells].

PURPOSE: To evaluate the dose of (188)Re that completely suppresses growth and clonogenic activity of human aortic smooth muscle cells (haSMC) since these cells are mainly responsible for restenosis occurring after PTA. For comparison, growth and clonogenic activity of endothelial cells (EC) were investigated with corresponding doses. MATERIALS AND METHODS: Two days after plating, haSMC and EC were incubated with (188)Re for five days. The doses applied ranged from 4 to 16 Gy. Cell growth was observed for a period of 20 days (EC) or 30 days (haSMC), respectively. Clonogenic activity was monitored over a period of 20 days for both cell lines. RESULTS: Irradiation caused dose-depend-ent inhibition of cell growth and clonogenic activity both in haSMC and in EC. HaSMC growth was completely blocked with 8 Gy, while EC still showed some proliferation even with 16 Gy. The clonal activity of haSMC was also completely blocked with 8 Gy while EC still showed little clonal activity even with 16 Gy. CONCLUSION: Cell growth of both haSMC and EC can be effectively suppressed in a dose-dependent manner. Only haSMC showed a complete growth arrest with 8 Gy while EC were able to proliferate even with 16 Gy. HaSMC colony formation was completely suppressed after application of 8 Gy, while the EC still showed colony formation activity with 16 Gy. (188)Re has some advantageous properties for intravascular irradiation in comparison to other radionuclides making it an interesting radionuclide for stent coating to prevent restenosis.

Angioplasty, Balloon↗
PubMed2004

[Possibilities of the prophylaxis of arterial restenoses with dexamethasone -- an in-vitro study of human aortic smooth muscle cells].

PURPOSE: To evaluate the effect of dexamethasone on the growth of cultured human aortic smooth muscle cells in an in-vitro model depending on the dose applied. MATERIALS AND METHODS: Commercially available human aortic smooth muscle cells (haSMC) were incubated with different doses of dexamethasone (10(-6), 10(-8), 10(-10) mol/l). For 20 days, the dose-depending effects of dexamethasone on cell growth were studied by analyzing cell proliferation, clonogenic activity as well as cell cycle distribution. In addition, the migratory ability of haSMC was evaluated using a two compartment in-vitro model. RESULTS: Cell growth was reduced in a dose dependent manner. An applied dose of 10(-6) M dexamethasone effectively inhibited cell growth for the follow-up period of 20 days. Cell cycle analysis revealed a G1-phase block which was dose dependent and significant for a dose of 10(-6) M. Also a reduction of haSMC clonogenic activity could be found in the colony formation assays. Finally, dexamethasone reduced the migratory ability of the treated cells significantly for doses of 10(-6) and 10(-8) M. CONCLUSION: Depending on the dose applied, incubation with dexamethasone results in a significant growth reduction of cultured haSMC, which may be due to a drug induced G1-phase block. Dexamethasone also reduces the clonogenic activity as well as the migratory ability of cultured haSMC.

Angioplasty, Balloon↗
PubMed2003

One case of gram-negative anaerobic spondylodiscitis with Prevotella intermedia.

We report the case of a 45-year-old woman with spondylodiscitis at L1/L2, communicating with paravertebral, intravertebral and bilateral psoas abscesses. Percutaneous computed tomography (CT)-guided abscess drainage and an intravenous antibiotic therapy with Imipenem were performed. After removing the drainage at 2 weeks, the patient was discharged at 4 weeks with normalized blood parameters, normal temperature, and without need for analgesics. The underlying bacterium in the case was a very rare gram-negative anaerobic bacterium: Prevotella intermedia.

Abscess↗
PubMed2003

[Microvascular denudation of the femoral artery of the mouse as a model for restenosis].

OBJECTIVE: To present technique and results of a microvascular denudation of the common femoral artery of the mouse as a model for inducing intimal hyperplasia in interventional radiology. MATERIALS AND METHODS: Under general anesthesia introduced by intraperitoneal injection, 14 B6129F1 hybrid mice (7 females and 7 males) at a mean age of 12.1 +/- 1.8 weeks and a mean weight of 28 +/- 2.8 grams had a groin incision of the vascular bundle directly distal to the inguinal ligament in preparation of placing a vascular clamp. Thereafter, the femoral artery was dissected distal to the origin of the epigastric artery and a loop prepared for a ligation proximal to the planned arteriotomy. Through an arteriotomy performed free-hand with a pair of micro scissors, a 0.010" (= 0.25 mm) guidewire was introduced into the vessel and advanced to the aortic bifurcation. The guide-wire was moved back and forth three times. The same procedure was performed on the other side as sham-operation, i.e., without introduction and passage of a guidewire. The resulting changes of the vessel wall were evaluated by histology and morphometry. RESULTS: Four weeks after intervention, the mean intima-to-media-ratio (IMR) was 1.80 +/- 0.28. A significant difference was observed between the sexes, with an IMR of 1.41 +/- 0.29 in females and an IMR of 2.24 +/- 0.45 in males (p = 0.0173). The neointima led to an overall luminal loss of 50.2% +/- 8.3% without significant sex difference (p = 0.09), but the average luminal loss was still more severe in females, amounting to 43.9% in comparison to 56.1% in males. This technique induces a significant neointima formation in a reproducible manner. The internal elastic membrane was preserved in all vessels. CONCLUSION: This technique is an excellent model to examine the differences between genetically modified mice to clarify the role of putative key molecules in the pathophysiology of restenosis.

Angioplasty, Balloon↗
PubMed2002

Endovascular treatment of peripheral artery disease with expanded PTFE-covered nitinol stents: interim analysis from a prospective controlled study.

PURPOSE: Current covered peripheral stent designs have significant drawbacks in terms of stent delivery characteristics and flexibility. The aim of this study was to analyze the technical performance, safety and initial clinical efficacy of expanded polytetrafluoroethylene (PTFE)-covered nitinol stents for arteriosclerotic peripheral artery disease. METHODS: Eighty-two patients underwent implantation of PTFE-covered nitinol stents for iliac and/or femoral obstructions. The study was conducted prospectively in seven European centers and one Canadian center. Patients were controlled clinically and by duplex ultrasound follow-up. Data up to discharge were collected in 79 patients. Seventy-four patients have thus far received 1 month follow-up and 32 patients, 6 month follow-up examinations. RESULTS: The average lesion length measured 47 mm for the common and external iliac arteries and 50 mm for the femoral arteries. The mean severity of the stenoses was reduced from 94% to 4% in the iliac arteries and from 98% to 7% in the femoral arteries after stent placement and dilatation. One device deviation (inadvertent stent misplacement) and one puncture-related severe adverse event with formation of a pseudoaneurysm occurred. There were occlusions of the stent in five patients. No infections were noticed. CONCLUSION: The interim analysis of this trial using PTFE-covered nitinol stents indicates that a strategy using primary implantation of this stent type is technically feasible, has an acceptable safety profile and is effective from a short-term perspective.

Alloys↗
PubMed2002

[Economical analyses in interventional radiology].

Considerations about the relation between benefit and expenses are also gaining increasing importance in interventional radiology. This review aims at providing a survey about the published data concerning economical analyses of some of the more frequently employed interventions in radiology excluding neuroradiological and coronary interventions. Because of the relative scarcity of literature in this field, all identified articles (n = 46) were included without selection for methodological quality. For a number of radiological interventions the cost-effectiveness has already been demonstrated, e. g., PTA of femoropopliteal and iliac artery stenoses, stenting of renal artery stenoses, placement of vena-cava filters, as well as metal stents in malignant biliary and esophageal obstructions. Conflicting data exist for the treatment of abdominal aortic aneurysms. So far, no analysis could be found that directly compares bypass surgery versus PTA + stent in iliac arteries.

Angioplasty, Balloon↗
PubMed2002

[Endovascular implantation of stent-grafts in the thoracic aorta -mid-term results of a prospective controlled study].

PURPOSE: To evaluate the effectiveness and safety of endovascular treatment of various descending thoracic aortic pathologies with covered stent-grafts as an alternative to open surgery. METHODS: Among 16 patients (5 type B dissections, 5 contained ruptures, 3 aneurysms of the descending aorta, 1 thoraco-abdominal aneurysm, 1 mural thrombosis, 1 patch aneurysm) treated between November 1997 and November 2000, eight patients received Talent stent-grafts and another 8 patients underwent a Gore-TAG stent-graft implantation. A clinical follow-up and control CT scans were obtained after the procedure and then at six-month intervals. RESULTS: Deployment of the stent-grafts was technically successful in all cases. Sufficient aortic reconstruction was achieved in all but one patient who needed surgical treatment. One patient died two days after the procedure from aortic rupture due to retrograde type A dissection. Another patient died 19 months after the procedure from an unknown cause. There was no occurrence of distal embolization, paralysis or infection. During follow-up, all patients remained free from recurrence or late complications of their disease. CONCLUSION: Endoluminal treatment of thoracic aortic pathologies with covered stent-grafts appears to be a safe and feasible method with at least mid-term efficacy.

Adult↗
PubMed2001

Prophylaxis of restenosis with (186)re-labeled stents in a rabbit model.

BACKGROUND: Intraluminal beta-irradiation has been shown to decrease neointimal proliferation after angioplasty in experimental models. The purpose of this study was to test the technical feasibility and biological effects of (186)Re-labeled stents. METHODS AND RESULTS: Thirty-four New Zealand White rabbits were fed a 0.5% cholesterol diet before balloon angioplasty and insertion of Palmaz stents in the infrarenal aorta. The animals were killed 7 weeks after stent implantation. Two of 34 animals died prematurely (aortic leak, pneumonia). Control stents (n=7) were compared with (186)Re stents (2.6 MBq [n=6], 8.1 MBq [n=5], 16.0 MBq [n=6], and 25.3 MBq [n=8]). Stent application was successful in all cases. No thrombus occlusion was observed. After 7 weeks, neointima formation was 2.2+/-0.2 mm(2) in the control group. In the treatment groups, a dose-dependent neointima reduction was detectable (0.5+/-0.5 mm(2) [2.6 MBq], 0.4+/-0.4 mm(2) [8.1 MBq], and 0 mm(2) [16.0 MBq, 25.3 MBq]). No induction of neointimal formation was observed at the edges of the stents. Radiation resulted in delayed reendothelialization. CONCLUSIONS: (186)Re stents were capable of reducing neointima formation in a dose-dependent fashion. (186)Re stents did not cause late thrombosis or neointimal induction at the stent margins in the observation period of 7 weeks.

Animals↗
PubMed2001

Rhenium-188 for inhibition of human aortic smooth muscle cell proliferation.

PURPOSE: To evaluate dose-dependent growth-modulating effects of the beta-gamma emitter Rhenium-188 on cultured human aortic smooth muscle cells (haSMC). METHODS AND MATERIALS: HaSMC were plated in 25 cm(2) flasks. Two days after plating, cells were incubated with the Re-188 (beta E(max) 2.12 MeV, tissue range(max) < 10 mm, T(1/2) 17 h) for five days. The doses administered were 0.2 Gy, 1, 4, 6, 8, 16, and 32 Gy. After five days, the radionuclide was removed. Cell growth, cell cycle distribution, and clonogenic activity were analyzed for the following 25 days. RESULTS: The 0.2 and 1 Gy groups did not show relevant growth-inhibiting effects compared to the control groups. The 4 to 32 Gy groups presented dose-dependent growth inhibition, with a complete growth arrest of the 16 and 32 Gy groups. Clonogenic activity of the smooth muscle cell was strongly inhibited from doses > or =8 Gy. Flow cytometry showed a lasting dose-dependent G2/M phase block. CONCLUSION: Smooth muscle cell (SMC) growth can be controlled effectively with Re-188 for at least 25 days after radiation in vitro. As the first four weeks after arterial angioplasty are crucial concerning neointimal formation, Re-188 may be a valuable radionuclide to inhibit restenosis after arterial angioplasty.

Aorta↗
PubMed2001

MR-guided biopsy of musculoskeletal lesions in a low-field system.

Thirty magnetic resonance (MR)-guided biopsies were obtained from 20 skeletal and 10 soft-tissue lesions in 31 patients using an open 0.2 T MR system equipped with interventional accessories. The results from aspiration (N = 3), core biopsy (N = 15), and transcortical trephine biopsy (N = 12) were evaluated for accuracy and clinical efficacy. Specimens were successfully obtained from 29 patients. Results were clinically effective in 23 patients, rated definitive in 16, nonconclusive in 9, and unspecific in 2 patients. A false diagnosis due to sampling error occurred in 2 patients, and biopsy sampling was impossible in one case. The best diagnostic yield was achieved from nontranscortical biopsies of osteolytic or soft-tissue masses. Results from transcortical biopsies were less specific due to the predominance of benign lesions. MR fluoroscopy for needle guidance was applied in 13 patients. Complete needle placement inside the magnet could be performed in 16 patients. MR-guided biopsy using an open low-field MR imager is feasible and clinically effective and will become a valuable tool in the management of musculoskeletal lesions. J. Magn. Reson. Imaging 2001;13:761-768.

Adolescent↗
PubMed2001

[Technique and results of CT-guided percutaneous bone biopsy].

PURPOSE: The aim of the study was to evaluate the feasibility and results of CT-guided percutaneous bone biopsy (PBB) of unknown bone lesions in a representative number of patients. METHODS: In 92 patients (100 biopsies) with different bone lesions CT-guided PBB was performed. RESULTS: The rate of technical success, defined as a successful retrieval of a sufficient tissue sample which then was sent for histological evaluation, was 89% (89/100 biopsies). The diagnostic accuracy was defined as a clinically useful histological result and was obtained in 80% (80/100 biopsies). Minor complications (minimal bleedings) occurred in 3% of all biopsies, no special therapy was necessary. Osteolytic lesions (92%) were classified more accurately by PBB than osteoplastic (80%) or mixed lesions (67%). Considering the anticipated dignity of the lesions prior to PBB, the suspected malignant bone lesions had a better diagnostic accuracy of 82% than the suspected benign bone lesions with an accuracy of 50%. CONCLUSION: Due to its universal availability combined with a low risk and a high diagnostic value the PBB of unknown bone lesions can be regarded as a valuable diagnostic tool. However, leave-me-alone lesions should be excluded.

Biopsy, Needle↗
PubMed2001

Tc-99m-labeled endothelin derivative for imaging of experimentally induced atherosclerosis.

OBJECTIVE: to characterize the potential of an endothelin derivative labeled with technetium-99m (Tc-99m) for the imaging of experimentally induced atherosclerosis. METHODS: neointima of different cellularity and severity of stenosis was induced in 32 rabbits by balloon denudation followed by distinct dietary regimens and drug application. Angiograms and scintigrams after injection of the Tc-99m-labeled endothelin derivative were obtained. The aorta was dissected for autoradiography, sudan-III-staining, morphometry, and immunohistology. RESULTS: the lesions induced could be detected in vivo (whole body scintigram) in all the animals 15 min after the injection of the Tc-99m endothelin derivative. Autoradiography revealed a strong relationship between tracer accumulation and sudan-III-staining of lesions. Accumulation of the endothelin derivative correlated with the number of neointimal smooth muscle cells (SMC), but not with the number of medial SMC, neointimal macrophages, and neointimal area. CONCLUSIONS: the results indicate that in vivo imaging of atherosclerosis with an endothelin derivative is a feasible method of detecting and characterizing atherosclerotic arterial wall lesions at early stages.

Angiography↗
PubMed2001

New strategies in platelet inhibition in noncoronary interventions.

Thrombembolic complications frequently occur during and after endovascular procedures because of associated arterial injury and thrombotic characteristics of implanted devices such as stents. New strategies in platelet aggregation inhibition are now available blocking the final and common pathway of platelet aggregation, the glycoprotein IIb/IIIa receptor. This treatment modality seems to be more effective for prophylaxis and prevention of thrombembolic complications than standard antiplatelet therapy. Most of the data provided for glycoprotein IIb/IIIa receptor blockade are derived from studies of coronary interventions. This report reviews the pharmacodynamic differences of classic and new drugs for platelet inhibition and the basic considerations for antiplatelet therapy in noncoronary interventions.

Arteries↗
PubMed2001

[Dose-dependent effects of the combined beta/gamma emitter 186-Rhenium on the growth of human vessel wall cells].

PURPOSE: The aim of this study was to evaluate the capability of human aortic smooth musc e cells (HaSMC) and endothelial cells (EC) to recover after incubation with the combined beta/gamma emitter 186rhenium. MATERIALS AND METHODS: Two days after plating, HaSMC and EC were incubated for five days with 186Re (total doses applied 4 Gy-32 Gy). Cell counts were performed for a period of 30 days (haSMC) and 22 days (EC). To detect possible growth recovery, colony formation assays were plated for both cell types on day 5, 10, and 20 (and lay 30 for haSMC). RESULTS: Both cell types presented a dose-dependent growth inhibition which was maximum at a dose of 32 Gy. Human endothelial cells presented with total growth recovery at 4 and 8 Gy, and a partial growth recovery at 16 Gy. Smooth muscle cells only presented partial growth recovery at 4 and 8 Gy. At 16 Gy and more no recovery was detected. CONCLUSION: HaSMC as well as EC growth can be modulated effectively with 186Re over a period of 30 days in vitro. Compared to smooth muscle cells human endothelial cellls seem to possess a higher potential to recover at doses of 8 to 16 Gy. 186Re may be a valuable radionuclide to prevent restenosis.

Angioplasty, Balloon↗