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.

[Loco-regional lysis with thrombosis older than 10 days: experiences and outcome]. / Erfahrungen mit der lokoregionalen Fibrinolysetherapie bei Thrombosealter über 10 Tage.

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.

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.

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.

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.

Homing of intravenously and intralymphatically injected human dendritic cells generated in vitro from CD34+ hematopoietic progenitor cells.

Dendritic cells (DC) are professional antigen-presenting cells that can be generated in vitro from CD34+ peripheral blood progenitor cells by recombinant cytokines. These cells have potential implications for immunotherapeutic approaches in the treatment of cancer and other diseases. Physiologically, immature DC in the periphery capture and process antigens, then mature to interdigitating DC and migrate to lymphoid organs, where they activate lymphocytes. However, it is not known if DC generated in vitro have the capacity to traffic in vivo to the lymphoid tissues, such as spleen and lymph nodes. We have investigated whether human radiolabeled DC differentiated in vitro migrate and localize to lymphoid tissues after intravenous and intralymphatic injection. The distribution and localization of the DC were evaluated in five patients with malignant melanoma using serial whole-body gamma camera imaging. Intravenously infused DC demonstrated transient lung uptake followed by localization in the spleen and liver for at least 7 days. DC injected into a lymphatic vessel at the dorsal foot were rapidly detected in the draining lymph nodes where they remained for more than 24 h. These data suggest that DC differentiated in vitro localize preferentially to lymphoid tissue, where they could induce specific immune responses.

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.

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.

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.

[Percutaneous revascularization of renal artery stenosis. Balloon angioplasty vs. stent implantation]. / Perkutane Revaskulärisation von Nierenarterienstenosen. Ballonangioplastie versus Stentimplantation.

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.

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.

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.

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.

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.

Renal artery occlusion model in dogs for the evaluation of thrombolytic agents.

The purpose of this study was to develop a model of renal artery occlusion and to investigate the effects of various thrombolytic agents on an acute occlusion of the renal artery with respect to ischemic tolerance of renal parenchyma. In order to do this, a thrombosis model in dogs (n = 36) was established and a total of 72 dorsal renal arteries occluded using autologous clot material. For the in vitro preparing of a clot, autologous blood (20 mL) was withdrawn and 100 U thrombin immediately added. Then 1 mL of the clot material was injected into the dorsal branch of the exposed renal artery. The dogs were divided into 8 groups (2 control groups, 6 therapy groups with local and systemic thrombolytic therapy). Thrombolysis was performed using urokinase, single-chain urokinase, and recombinant tissue-plasminogen activator. In all cases the clot preparation technique allowed complete and stable occlusion of the renal arteries. Local and systemic application of the thrombolytic agents, however, resulted in complete recanalization of the clot material in all study groups. Recombinant tissue-plasminogen activator turned out to be the most effective agent in terms of recanalization time. The technique described allowed effective and reproducible artery occlusion for in vivo experimental work to study comparatively thrombolytic agents with respect to fibrin specificity, lytic efficacy, and side effects.

Late occurrence of cysts in autosomal dominant medullary cystic kidney disease.

Medullary cystic kidney disease (MCD) is characterized by multiple renal cysts at the corticomedullary boundary area, by autosomal dominant inheritance, and by onset of chronic renal failure in the third decade of life. We report on a family with three affected individuals of both sexes in two generations presenting with end-stage renal failure at age 22-31 years. Primarily diagnoses considered included unclassified hereditary nephropathy and autosomal dominant polycystic kidney disease. Careful evaluation of all findings, initiated after investigation of renal morphology with CT, revealed features characteristic for MCD and led to the final diagnosis of MCD. We conclude that MCD is an important differential diagnosis for polycystic kidney disease in young adults with end-stage renal failure. Establishing the correct diagnosis has considerable impact for genetic counselling.

Two-center German experience with aortic endografting.

PURPOSE: To report the results of a two-center study of endovascular abdominal aortic aneurysm (AAA) exclusion using a polyester-covered nitinol stent-graft. METHODS: Candidates were evaluated with arteriography and computed tomography. Criteria for endovascular therapy were a proximal aortic neck > 10 mm in length and < 25 mm in diameter, no bilateral internal iliac artery involvement in the aneurysm, no markedly tortuous common iliac arteries (CIAs) or CIAs < 7 mm in diameter, and no superior mesenteric artery occlusive disease. Patients were treated with the Mialhe Stentor and Vanguard stent-grafts in either tube or bifurcated versions. RESULTS: Between August 1994 and November 1996, 149 patients (mean age 67 years, range 49 to 90) were admitted to the study. Overall primary technical success (aneurysm exclusion without endoleak) was 87% (130 patients): 78% (7 patients) for tube grafts and 88% (123 patients) for bifurcated endografts. The rate of local, remote, or systemic complications was 10.8%, with a 30-day mortality rate of 0.7%. During an average 13.5-month follow-up, there were no late deaths. Four of 20 endoleaks sealed spontaneously, 14 were treated with endoluminal techniques, and 2 remain untreated by patient request. Three graft limb thromboses occurred; one was treated surgically, one with lytic therapy, and one was untreated. Secondary patency was 96%. CONCLUSIONS: Endoluminal repair of infrarenal AAAs using straight or bifurcated grafts is a feasible alternative to conventional surgical repair. Longer follow-up and more experience with refined endograft models will elucidate the durability of this endovascular approach to treating AAAs.