PubMed Health⌕ Search

Biomedical subjects

U Blum

Publications and source records attributed to U Blum.

At least 19 recordsLinked to original sources
PubMed2005

Validation of IC-VIEW fluorescence videography in a rabbit model of mesenteric ischaemia and reperfusion.

BACKGROUND/AIMS: Mortality in mesenteric ischaemia can be reduced by an optimised extent of resection. Up to now, no technique supplementing a surgeon's experience has achieved clinical acceptance. Besides a qualitative interpretation, the new technique of computer-assisted laser-fluorescence videography affords quantification of staining intensities. The aim of this study was to investigate the scientific value of this technique in mesenteric ischaemia in a rabbit model of controlled mesenteric ischaemia and reperfusion. METHODS: We used an established rabbit model of mesenteric ischaemia (group I, n=6) and reperfusion (group II, n=6). In each animal, three loops (each of 10 cm) of the small intestine were clamped (group I, 40 min; group II, 60 and 20 min reperfusion). For further evaluation, all loops were divided into five segments of 2 x 2 cm (total number of investigated areas, n=180). Measurement of vascular patency was performed by laser-fluorescence videography (pixel intensity per second). As standard, we used radioactive microspheres (impulse per minute per gram). In addition, the extent of ischaemic tissue damage was identified by histological examination. Statistical data were analysed by using regression analysis to define the regression coefficient r. RESULTS/FINDINGS: Laser-fluorescence videography and the microsphere technique demonstrated a close and linear correlation: ischaemic segments, r=0.90+/-0.07; reperfusion segments, r=0.85+/-0.02; overall, r=0.92+/-0.07. There was no reproducible correlation to cellular damage in histology. INTERPRETATION/CONCLUSION: Computer-assisted laser-fluorescence videography is a feasible, reliable, and valid experimental method for the detection of mesenteric blood supply and intestinal microcirculation. Clinical application is conceivable in mesenteric ischaemia and infarction as well as the operative transposition of intestine. As limiting values to identify the irreversible necrosis are not yet defined, further studies have to analyse the clinical impact more precisely.

Animals↗
PubMed2002

[Loco-regional lysis with thrombosis older than 10 days: experiences and outcome].

Successful treatment of deep vein thrombosis by lysis therapy leads to recanalisation of the occluded vessel saving the venous flaps, thus limiting postthrombotic syndrome. Systemic lysis therapy carries an increased risk of fatal complications (1-2%). However, loco-regional lysis therapy with rtPA stands out as a method of recanalisation without increased complications compared to compression and anticoagulation therapy. According to the leading opinion about systemic lysis therapy it should only be performed if thrombotic age does not exceed 10 days. In this study we examined whether loco-regional lysis therapy is successful with older thrombosis, too. We showed that in thromboses older than 10 days lysis success was slightly decreased whereas postthrombotic syndrome doubled (up to 50%). These results point out loco-regional lysis as a method suitable for thromboses with age up to 10 days only.

Fibrinolytic Agents↗
PubMed2001

Percutaneous endoprosthesis for treatment of aortic aneurysms.

The purpose of this study was to define the clinical utility of stent-grafts for endoluminal treatment of infrarenal abdominal aortic aneurysms (AAAs). In a prospective study involving three centers, bifurcated stent-grafts for endovascular repair of infrarenal AAAs were implanted in 295 patients. Patient selection was based on anatomic suitability. For analysis of the initial and follow-up results the patients were divided in three subgroups. Group 1 included patients treated between August 1994 and April 1996 with use of the original stent-graft device; group 2 comprised patients treated between May 1996 and December 1997 with the refined stent-graft device, and group 3 comprised patients treated with a newly designed bifurcated stent-graft device. In group 1 (n = 111) the primary technical success was 82%. The procedure had to be converted to surgery in four patients. Endoleaks immediately after the procedure were observed in 16 patients. The initial technical success in subgroup 2 (n = 159) was 96%. One patient required surgical repair, and five others had immediate perigraft flow due to reperfusion via lumbar arteries. For group 3 (n = 28) the primary technical success rate was 89%. Endoleaks due to back-bleeding via lumbar arteries were demonstrated in three patients. Minor and major complications related to the intervention, including two perioperative deaths, were observed in 24 patients (8%). Serious problems such as distal migration or disconnection of the stent-graft were detected during follow-up in five patients. Delayed aortic rupture occurred in three patients who survived after successful surgical repair. Based on the initial results and a limited follow-up of 35 months, we believe endoluminal repair of infrarenal AAA with use of bifurcated endografts may be a feasible alternative to conventional surgery, especially for patients at high surgical risk. However, at the present time there are major concerns with respect to the structural integrity of stent-graft material and the fate of the proximal aortic cuff in the long-term time frame.

Aged↗
PubMed2001

Can simultaneous inhibition of seedling growth and stimulation of rhizosphere bacterial populations provide evidence for phytotoxin transfer from plant residues in the bulk soil to the rhizosphere of sensitive species?

In order to demonstrate that allelopathic interactions are occurring, one must, among other things, demonstrate that putative phytotoxins move from plant residues on or in the soil, the source, through the bulk soil to the root surface, a sink, by way of the rhizosphere. We hypothesized that the incorporation of phytotoxic plant residues into the soil would result in a simultaneous inhibition of seedling growth and a stimulation of the rhizosphere bacterial community that could utilize the putative phytotoxins as a sole carbon source. If true and consistently expressed, such as relationship would provide a means of establishing the transfer of phytotoxins from residue in the soil to the rhizosphere of a sensitive species under field conditions. Presently, direct evidence for such transfer is lacking. To test this hypothesis, cucumber seedlings were grown in soil containing various concentrations of wheat or sunflower tissue. Both tissue types contain phenolic acids, which have been implicated as allelopathic phytotoxins. The level of phytotoxicity of the plant tissues was determined by the inhibition of pigweed seedling emergence and cucumber seedling leaf area expansion. The stimulation of cucumber seedling rhizosphere bacterial communities was determined by the plate dilution frequency technique using a medium containing phenolic acids as the sole carbon source. When sunflower tissue was incorporated into autoclaved (to reduce the initial microbial populations) soil, a simultaneous inhibition of cucumber seedling growth and stimulation of the community of phenolic acid utilizing rhizosphere bacteria occurred. Thus, it was possible to observe simultaneous inhibition of cucumber seedlings and stimulation of phenolic acid utilizing rhizosphere bacteria, and therefore provide indirect evidence of phenolic acid transfer from plant residues in the soil to the root surface. However, the simultaneous responses were not sufficiently consistent to be used as a field screening tool but were dependent upon the levels of phenolic acids and the bulk soil and rhizosphere microbial populations present in the soil. It is possible that this screening procedure may be useful for phytotoxins that are more unique than phenolic acids.

Amaranthus↗
PubMed2000

Palliative treatment of a secondary aortoduodenal fistula by stent-graft placement.

A 64-year-old male was admitted with suspected aortoduodenal fistula 16 years after transabdominal aortic reconstruction for aortoiliac occlusive disease. Computed tomography (CT) and angiography revealed an aortoduodenal fistula and a suture-line aneurysm at the proximal anastomosis. Due to the patient's poor general condition at the time of diagnosis, endoluminal stent-graft implantation was chosen rather than conventional surgery. Successful placement of the stent graft without leakage of contrast medium and with complete exclusion of the fistula was demonstrated by CT. The patient recovered uneventfully and was discharged 10 days after the intervention. Five months later contrast CT indicated a recurrence of the aortoduodenal fistula. Since the patient was now in good general condition the stent graft was removed surgically and an extra-anatomic axillofemoral bypass was implanted. Endoluminal stent-graft Implantation is effective as palliative therapy for aortoduodenal fistulas and is especially valuable in patients with high risk for conventional surgery.

Aortic Diseases↗
PubMed1999

[Percutaneous revascularization of renal artery stenosis. Balloon angioplasty vs. stent implantation].

Renal artery stenosis (RAS) is the most common cause of secondary hypertension, with a prevalence of about 1% in the general population of people with hypertension. Severe arterial stenosis may also lead to impairment of excretory renal function. In experienced hands renal artery revascularization with or without stent implantation may be a safe and effective treatment in patients with sustained hypertension resistant to intensive antihypertensive treatment. Conventional balloon angioplasty of non-ostial RAS caused by fibromuscular dysplasia with a high technical and functional success rate may be the treatment of choice. However, there is continuous discussion concerning the utility of balloon angioplasty and renal stenting, respectively, in patients with atherosclerotic disease. At the time being, there are 3 randomized European trials ongoing to analyze the benefit of medical treatment versus percutaneous intervention. Several prospective studies dealing with renal artery stenting in ostial RAS found that the implantation of endoprostheses leads to much better morphologic longterm results as compared to those of balloon angioplasty alone and may be a safe and effective alternative to surgery. In addition, the functional results suggest that stent implantation in patients with mild or severe renal dysfunction may slow progression of renal failure and, thus delay the need for renal replacement therapy. It is to note that renal artery stenting does not impede any further surgical intervention. However, prior to any interventional treatment the indication of an eventual catheter procedure in patients with RAS should be discussed between experienced nephrologists and interventionalists based on clinical, functional and duplexsonographic data.

Angioplasty, Balloon↗
PubMed1999

Diagnostic and surgical approach of innominate artery saddle embolus.

Patients with an acute arterial occlusion of the right upper extremity and absent axillary pulse should have a Doppler scan examination before a balloon catheter embolectomy is performed. If there is no arterial pulse detectable, an angiography should be performed afterwards to localize the embolus. In the case of a proximal arterial occlusion of the right arm, the authors recommend this procedure to prevent an embolus dislocation by catheter embolectomy and subsequent cerebral embolization. For direct surgical embolectomy the authors recommend a supraclavicular incision.

Aged↗
PubMed1999

Reducing the post-pump syndrome by using heparin-coated circuits, steroids, or aprotinin.

BACKGROUND: Cardiopulmonary bypass (CPB) induces a systemic inflammatory response called 'post-pump syndrome'. As a part of a complex interaction between white cells and vascular endothelium, proinflammatory cytokines IL-6 and IL-8 are part of a phased immune response that is also balanced by anti-inflammatory cytokines such as IL-10. We compared the influence of heparin-coated circuits, steroids, and aprotinin on these cytokines, looking for ways to reduce the syndrome. METHODS: 40 patients with coronary artery disease (CAD) undergoing elective CABG were prospectively studied in four randomized groups of 10. Group A received prednisolone pre- and postoperatively (2 x 250 mg), group B received aprotinin perioperatively (6 Mio. KIU). In group C, heparin-coated circuits ('Bioline' by Jostra) were used and in group D no special measures were taken (controls). Plasma levels of cytokines were measured before and during CPB and until 12 h after surgery using an ELISA technique. RESULTS: In group A IL-6 was significantly (p<0.05) suppressed in contrast to the control group (A: peak at 4 h, 155 pg/ml vs. control: peak at 8 h, 565 pg/ml). IL-8 was also suppressed (A: peak at 30', 22 pg/ml vs. control: peak at 30', 55 pg/ml). IL-10 level changed first and was markedly upregulated in contrast to the control (A: peak at 30', 1600 pg/ml vs. control: peak at 30', 130 pg/ml; p<0.05). In group B (aprotinin) the cytokine release was similar to group A. Using heparin-coated circuits (group C) also led to a significant (p<0.05) IL-10 upregulation (C: peak at 2 h, 1380 pg/ml) and IL-6 suppression (C: peak at 4 h, 290 pg/ml). IL-8 was not influenced significantly. CONCLUSIONS: The results show a similar reduction of the inflammatory cytokine release (IL-6 and IL-8 as markers) using early steroid application and aprotinin in high dosage. Heparin coating reduces IL-6 and increases IL-10 release, whereas IL-8 is not affected. Further studies should investigate the effects of a combined application for reducing inflammatory cytokine release and the post-pump syndrome.

Aged↗
PubMed1999

Cerebral and renal embolization after lymphography in a patient with non-Hodgkin lymphoma: case report.

An unusual case of lipid embolization to brain and kidney after lymphography in a patient with non-Hodgkin lymphoma of the upper anterior mediastinum is reported. Contrast material-enhanced echocardiography demonstrated a right-to-left shunt to the left atrium without evidence of a patent foramen ovale. Echo contrast particles were transiently present within the tumor surrounding the great vessels.

Adult↗
PubMed1998

Survival benefit of patients with inoperable hepatocellular carcinoma treated by a combination of transarterial chemoembolization and percutaneous ethanol injection--a single-center analysis including 132 patients.

Hepatocellular carcinoma (HCC) is one of the most severe sequelae of chronic liver disease. The only potentially curative therapeutic options are surgical resection and orthotopic liver transplantation. In most HCC patients, however, at clinical presentation the tumors are unresectable because of multicentricity or poor hepatic functional reserve due to pre-existing cirrhosis or not transplantable because of too advanced tumor stage or severe co-morbidity. In clinical practice, therefore, percutaneous ethanol injection (PEI) and transarterial chemoembolization (TACE) are widely used non-surgical therapeutic strategies. We prospectively analyzed the clinical factors determining the prognosis of 132 inoperable HCC patients and assessed the feasibility, therapeutic efficacy and safety of PEI, TACE and a combination thereof. Mean age of patients was 64 years; 95% of patients had liver cirrhosis and 39% were Okuda stage I, 48% stage II and 13% stage III. Fifteen patients were treated by PEI (group 1), 33 by TACE (group 2), 39 by TACE and PEI (group 3) and 45 received best supportive care (group 4). Survival correlated with the Child-Pugh class of liver cirrhosis and the Okuda stage of HCC. Favorable prognostic parameters were alpha-fetoprotein (AFP) levels <100 ng/ml and absence of portal vein thrombosis. Median survival time was 18 months in group 1 [interquartile range (IQR) 10-19], 8 months in group 2 (IQR 5-15), 25 months in group 3 (IQR 13-36) and 2 months in group 4 (IQR 1-9). Multivariate analysis revealed that patients treated with a combination of TACE and PEI have a significantly better survival than patients receiving either PEI or TACE only (p = 0.001). Patients with inoperable HCCs treated by the combination of TACE and PEI have a clear survival benefit. A favorable outcome can be expected in patients with compensated cirrhosis, a low Okuda stage, a baseline AFP level <100 ng/ml and absence of portal vein thrombosis.

Administration, Cutaneous↗
PubMed1998

Imaging of renal artery stenosis.

Renal artery stenosis is the cause of progressive ischemic nephropathy and of renovascular hypertension. Due to the invasiveness of arteriography, which is claimed to be the gold standard at the present time, several noninvasive imaging techniques are available. Colour Doppler sonography is cost-effective, but magnetic resonance angiography and computer tomography are more expensive; however, both are potential candidates for the definition of a new gold standard. Evaluation of renal vasculature by means of Doppler sonography includes intra- and extrarenal scanning as well as power Doppler and the use of contrast agents for enhancement of the Doppler signals. Computed tomography angiography is a minimally invasive method for the diagnosis of renal artery stenosis. There is high diagnostic accuracy that is not significantly different from that of angiography with respect to main and accessory renal arteries and detection of clinically significant renal artery stenoses. The main advantages over angiography are the use of an intravenous approach, and direct information provided about the vessel wall and adjacent structures. However, the nephrotoxicity of contrast material remains a major concern. Magnetic resonance angiography of the abdominal aorta and renal arteries has advanced considerably over the past few years. Recently developed breath-hold three-dimensional magnetic resonance angiography provides a new promising, noninvasive technique to evaluate the abdominal aorta and its large branch vessels. Using this technique, high sensitivity and specificity is achieved. The improved image quality and the ability to detect vascular lesions is due to short acquisition time with elimination of respiratory artifacts over an entire imaged volume by single breath-hold acquisition. Computed tomography angiography with its fast acquisition time and high spatial resolution compares favorably with magnetic resonance angiography and colour Doppler sonography. However, as compared with Doppler sonography and magnetic resonance angiography, computed tomography angiography images display only anatomic information and lack of flow sensitivity.

Journal Article↗
PubMed1998

Unusual cause of early graft dysfunction after kidney transplantation.

BACKGROUND/AIMS: Transplant renal artery stenosis usually develops in the later period after renal transplantation and is usually due to atherosclerosis and fibrosis at the anastomosis. A kinking renal artery stenosis, however, is a rare cause of early graft dysfunction. METHODS: In a 34-year-old-man early graft failure developed within 1 week after kidney transplantation. In the presence of histologically proven ischemic damage an arterial kinking stenosis was diagnosed by color Doppler sonography. Selective arteriography confirmed the sharp kinking of the transplant renal artery; however, a significant stenosis could not be visualized by arteriography. RESULTS: Due to progressive loss of renal function surgical resection of scar tissue in the kink of the transplant artery and nephropexy was performed. Immediately thereafter graft function and blood pressure significantly improved so that the successful clinical outcome of this unusual case of early graft failure confirmed the relevance of the arterial kinking stenosis. CONCLUSIONS: In this unusual case of early graft dysfunction relevant kinking renal artery stenosis could not be adequately visualized by arteriography, although color Doppler sonography clearly demonstrated the stenosis. Therefore, both methods should be considered if parenchymal causes of graft dysfunction are excluded by biopsy and a kinking renal artery stenosis is suspected.

Adult↗
PubMed1998

Cystic adventitial degeneration and entrapment syndrome of the popliteal artery as a differential diagnosis of popliteal stenosis or occlusion in the younger age group.

Differential diagnosis in angiographically found popliteal artery stenosis or occlusion comprises some distinct and clinically important entities that should be considered as management and prognosis may vary considerably. We present two patients with the final diagnosis of cystic adventitial disease of the popliteal artery and popliteal artery entrapment syndrome. Angiographic findings and the value of additional diagnostic imaging are discussed.

Adult↗
PubMed1997

Treatment of ostial renal-artery stenoses with vascular endoprostheses after unsuccessful balloon angioplasty.

BACKGROUND: Percutaneous transluminal renal angioplasty is a safe and effective treatment for nonostial stenoses of the renal arteries, but it has proved to be disappointing for ostial stenoses. Therefore, we prospectively studied the use of intravascular stents for the treatment of critical ostial stenoses after unsuccessful balloon angioplasty. METHODS: Stainless-steel endoprostheses were placed across 74 renal-artery stenoses located within 5 mm of the aortic lumen in 68 patients with hypertension. Twenty patients had mild or severe renal dysfunction. The indications for stent placement were elastic recoil (63 arteries) or dissection (1 artery) of the vessel after angioplasty, or restenosis after initially successful balloon angioplasty (10 arteries). Patients were followed for a mean of 27 months with measurements of blood pressure and serum creatinine, duplex sonography, and intraarterial angiography. RESULTS: Initial technical success was achieved in all patients. Minor complications (local hematomas) occurred in only three patients; there were no major complications. Eighty-four percent of the patients were free of primary occlusion 60 months after the procedure. Restenosis of more than 50 percent of the vessel diameter occurred in 8 of 74 arteries (11 percent). Reintervention resulted in a secondary patency rate of 92 percent. Long-term normalization of blood pressure was achieved in 11 patients (16 percent). Serum creatinine levels did not change significantly after successful stent implantation in patients with previously impaired renal function. CONCLUSIONS: Accurate placement of renal-artery stents is technically feasible without major complications. The favorable early and long-term results suggest that primary stent placement is an effective treatment for renal-artery stenosis involving the ostium.

Adult↗
PubMed1997

Endoluminal stent-grafts for infrarenal abdominal aortic aneurysms.

BACKGROUND: The treatment of aortic aneurysms with endovascular stents or stent-graft prostheses is receiving increasing attention as an alternative to major abdominal surgery. To define the clinical value of this technique, we prospectively studied the use of stent-graft endoprostheses made of nitinol and covered with polyester fabric for the treatment of infrarenal abdominal aortic aneurysms. METHODS: We treated a total of 154 patients at three academic hospitals. Twenty-one patients with aortic aneurysms not involving the aortic bifurcation received straight stent-grafts, and 133 patients with aortic aneurysms involving the bifurcation and the common iliac arteries received bifurcated stent-grafts. After a unilateral surgical arteriotomy, the endoprostheses were advanced through the femoral arteries and placed under fluoroscopic guidance. Computed tomography and intraarterial angiography were performed during an average follow-up of 12.5 months. RESULTS: The primary success rate, defined as complete exclusion of the abdominal aortic aneurysm from the circulation, was 86 percent in the group receiving straight grafts and 87 percent in the group receiving bifurcated grafts. In three patients the procedure had to be converted to an open surgical operation. Minor (n=13) or major (n=3) complications associated with the procedure (including 1 death) occurred in 10 percent of the patients. All patients had a postimplantation syndrome, with leukocytosis and elevated C-reactive protein levels. CONCLUSIONS: Our results suggest that endovascular treatment of infrarenal abdominal aortic aneurysms is technically feasible and can effectively exclude abdominal aortic aneurysms from the circulation. With further refinement, endoluminal repair may emerge as an interventional strategy to treat infrarenal aortic aneurysms, especially in patients at high surgical risk.

Adult↗
PubMed1997

[Interventional occlusion of systemicopulmonary collateral arteries using metal spirals].

Major systemicopulmonary collateral arteries (spca) frequently contribute to collateral lung perfusion in patients with pulmonary atresia and ventricular septal defect or in children with tetralogy of Fallot. Since the surgical access to these vessels is difficult, corrective surgery may become impossible. We report our experience with interventional occlusion of spca in 10 patients. In these patients (age range 13 months-19.5 years) selective injections demonstrated a total of 27 spca. Sixteen of these were coil-occluded by interventional cardiac catheterization. Total occlusion was achieved in 15 cases, in one case we found a small residual shunt. Occlusion was performed using platinum coils (2 cases), Gianturco coils (11 cases) and detachable steel coils (4 cases, including 1 with prior incomplete occlusion by Gianturco coils). 4 patients required 2 interventional cardiac catheterizations. Complications occurred only in procedures that were performed with conventional coils (peripheral pulmonary embolizations of platinum coils in 2 patients, dislocation of the delivery catheter with a partially extruded coil to the descending aorta in 1 patient). Operative ligation had to be performed in 6 spca, since those vessels were not suitable for interventional occlusion. The remaining 5 spca were left unoccluded, since they were of minor hemodynamic relevance due to a subsequent decrease in size. At the end of the follow-up period corrective surgery had been completed in 8 of our 10 patients. In the remaining 2 patients corrective surgery is planned in the near future. According to our experience interventional occlusion of spca is a major improvement in the management of a selected cohort of patients with pulmonary atresia and ventricular septal defect or tetralogy of Fallot. The introduction of detachable steel coils facilitates the embolization of those vessels.

Adolescent↗