PubMed Health⌕ Search

Biomedical subjects

T Zeller

Publications and source records attributed to T Zeller.

17 recordsLinked to original sources
PubMed2006

Current state of diagnosis and endovascular treatment of renal artery stenosis.

Renal artery stenosis may cause or deteriorate arterial hypertension and/or renal insufficiency. Technical improvements of diagnostic and interventional endovascular tools have lead to a more widespread use of endoluminal renal artery revascularization and extension of the indications for this type of therapy. Since the first renal artery angioplasties performed by Felix Mahler and Andreas Grüntzig in 1978, numerous single centre studies have reported the beneficial effect of percutaneous transluminal renal angioplasty, and since the early 1990's stenting of renal artery stenosis caused either by atherosclerosis or fibromuscular dysplasia. This article summarizes the impact of technical improvements of endovascular tools on interventional techniques during the last decade and gives an overview concerning the clinical impact of renal artery revascularization. Despite the absence of sufficient randomized studies there is nonetheless evidence that stenting of hemodynamically relevant atherosclerotic renal artery stenosis has an impact on blood pressure control, renal function, and left ventricular hypertrophy.

Angiography↗
PubMed2004

Histological verification of non-specific aorta-arteritis (Takayasu's arteritis) using percutaneous transluminal atherectomy.

Diagnosis of non-specific aorto-arteritis (NSAA, Takaysu's arteritis) is typically based on clinical and investigational parameters. We report here about two patients with clinically suspected diagnosis of a Takayasu's arteritis already under anti-inflammatory therapy in whom percutaneous transluminal atherectomy of subclavian and axillary artery stenoses was performed to relief the patients from symptoms--intermittent dyspraxia of the arms--and to verify the clinical diagnosis by histology. In the first case aorto-arteritis could be histologically confirmed through the analysis of plaque material including media structures excised from the subclavian and axillary arteries using a new device for atherectomy. The biopsy showed diffuse inflammation and granulomatous lesions with giant cells typically for Takayasu's disease. In the second patient, biopsy showed no acute or chronic inflammatory signs but only atherosclerotic lesions. Percutaneous transluminal atherectomy is therefore not only an interventional but also a diagnostic tool and should be used in every case of interventional therapy of suspected aorto-arteritis to make the clinical diagnosis and as a major consequence the initiation of an aggressive anti-inflammatory medical therapy more reliable.

Adult↗
PubMed2004

[Initial clinical experience with a new percutaneous peripheral atherectomy device for the treatment of femoro-popliteal stenoses].

BACKGROUND: Evaluation of the efficacy and safety of a new 7F-atherectomy device (30-day endpoint) for the treatment of short and mid-length arterial lesions with a reference diameter of 2.5-7 mm. MATERIAL AND METHODS: Fifty-eight femoto-popliteal stenoses in 46 patients (67% male, mean age 66 +/- 9 years) with chronic peripheral occlusive disease of the lower limbs [Rutherford stage 2: n = 13 (28%); stage 3: n = 29 (63%), stage 4: 2 (4%), stage 5: n = 2 (4%)], were treated with directional atherectomy. Target lesion characteristics: Common femoral artery: n = 1 (2%), superficial femoral artery: n = 47 (81%); popliteal artery, n = 10 (17%); in stent n = 3 (5 %). Thirty (65 %) of the interventions were performed using an antegrade approach, 16 (35%) interventions in cross-over technique. Mean degree of stenosis was 83 +/- 11 mm, mean length of lesion was 37 +/- 37 mm. RESULTS: 6.5 +/- 2 (4-10) passes of the lesion were performed with the catheter. Three lesions were treated after predilatation, 55 (95%) interventions as primary atherectomy. In 31/58 lesions (53%) additional balloon angioplasty was performed, in 1 lesion (2%) additional stent placement was needed. The mean degree of stenosis after atherectomy was reduced to 29 +/- 20% (0-60%) after additional balloon angioplasty, it was 11 +/- 10% (0-30 %). A residual stenosis of < 50% after plain atherectomy was achieved in 55 (95%) lesions, of < 30% in 49 (84%). COMPLICATIONS: 3 (6.5%) cases of embolism of debris were detected and treated successfully by aspiration. The mean ankle-brachial index increased from 0.62 +/- 0.12 to 0.92 +/- 0.36 before discharge, and to 0.86 +/- 0.17 after 30 days. Rutherford stage after 30 days: stage 0: n = 038 (83%); Stage 1: n = 4 (8%); Stage 2: n = 3 (6%); Stage 5: n = 1 (2%). CONCLUSION: Lesions up to 8 cm in length of the femoropopliteal arteries can be treated successfully in most cases with the new atherectomy catheter. Embolism, the only complication that occurred, can be avoided by cleaning the nose cone after at least 4 passes of the lesion.

Aged↗
PubMed2004

Excimer laser assisted angioplasty for the treatment of critical limb ischemia.

Two decades after the clinical introduction of percutaneous transluminal angioplasty (PTA), controversy still exists about the role of PTA for the treatment of occlusive disease in the femoropopliteal and infragenicular arteries. For the patient with critical limb ischemia (CLI), where diffuse disease and long occlusions are the rule, the results with PTA have not been optimal. Surgical revascularization has long been considered the gold standard for this patient population, but this procedure is associated with significant morbidity and mortality and up to 37% of patients may be poor surgical candidates. With advances in laser catheter design and refinement of recanalization techniques, improved results have been seen with laser assisted angioplasty of complex peripheral arterial disease. There has been renewed interest in excimer laser angioplasty for the treatment of patients with long total occlusions and diffuse disease who otherwise would have limited options for treatment. Excimer laser assisted angioplasty has been shown to be a successful approach to the treatment of long occlusions in the superficial femoral artery. Data from the recently completed Laser Angioplasty for Critical Limb Ischemia Phase 2 Trial (LACI) suggest that this is a viable treatment strategy for patients with CLI who are otherwise not good candidates for bypass surgery.

Aged↗
PubMed2003

Treatment of acute embolic occlusions of the subclavian and axillary arteries using a rotational thrombectomy device.

Acute embolic or local thrombotic ischaemia of the upper limbs can be treated by embolectomy or by endovascular techniques. We report here on the endovascular thrombectomy of acute embolic occlusions of subclavian and axillary arteries in two patients using a rotational thrombectomy device and give an overview about the actual literature. Two female patients, each with a history of multivessel coronary disease and intermittent atrial fibrillation, complained of sudden onset of pain at rest and paleness of the left and right arm, respectively. Duplex ultrasound showed a localized embolic occlusion of the left subclavian artery and the bifurcation of the brachial artery in the first patient and a localized embolic occlusion of the distal right subclavian and axillary artery in the second patient. In the first patient, the left subclavian artery was reopened using a 8F-Rotarex device via the femoral access, while the bifurcation of the brachial artery was reopened by local thrombolysis using 25 mg rt-PA because of the insufficient length of the thrombectomy device of 80 cm. In the second patient, the right subclavian and axillary arteries were reopened using a 6F-Rotarex device. Follow-up examinations before discharge and after 6 months showed normalized perfusion of the arms of both patients.

Acute Disease↗
PubMed2002

[First experiences with a 6F-sheath compatible self-expanding nitinol stent].

BACKGROUND: To evaluate the efficacy, safety and limitation of a new 6F-compatible nitinol stent (Dynalink(TM). MATERIAL AND METHODS: We treated 50 patients (17 women, 33 men, mean age 72 +/- 8 years) by implanting 80 Dynalink(TM)-stents into 75 vessels during a 6-month period. Target lesions were: iliac artery: 25, femoral artery: 31, popliteal artery: 16, femoro-popliteal bypass: 5, subclavian vein: 3. Preinterventional Rutherford classifications: Class 1 : 3 legs (5 %), class 2 : 27 legs (51 %), class 3 : 16 legs (31 %), class 4 : 2 legs (4 %), class 5 : 5 legs (9 %). 40 % stents each were implanted ipsilateral, 60 % cross-over. RESULTS: All interventions were successful regardless of a sometimes anatomically difficult access to the lesion. The device was characterised by a high flexibility and radial force and the stent did not shorten. COMPLICATIONS: One distal stent dislocation during placement occurred, no puncture site complication. The mean diameter stenosis was reduced from 91 +/- 10 % (75 - 100 %) to 4 +/- 8 % (0 - 30 %). The ankle-brachial index was improved from 0.46 +/- 0.22 to 0.75 +/- 0.23 (p < 0.001). Post-interventional Rutherford classifications: Class 0 : 43 legs (81 %), class 1 : 5 legs (4,5 %), class 5 : 5 legs (4,5 %). CONCLUSIONS: The new 6F-sheath compatible nitinol stent is characterised by a good flexibility, radial force, and a lack of shortening. By the reduction of the diameter of the device to 6F, the potential risk of a local bleeding complication may be reduced and 6F sealing devices will be usable. Disadvantages are the 0.018 inch guide-wire lumen and the limited stent sizes.

Adult↗
PubMed2002

[Normal values for the internal thoracic artery by Doppler ultrasound and modification of the Doppler curve after bypass to the left anterior descending artery].

AIM: In coronary heart disease, the surgical therapy of choice is the construction of an artenal bypass of the left anterior descending artery (LAD) using the internal thoracic artery 8ITA). We define age dependent normal values for the ITA such as diameter of the lumen (LD), peak systolic (Vs) and diastolic (Vd) flow velocity and the ratio of these two values (SDR) measured by duplex ultrasound. Furthermore, the modification and pathological changes of the Doppler curve after minimal invasive bypass of the LAD (MIDCAB) are described. MATERIAL AND METHODS: 96 people, age 18 - 87 years, subdivided into 6 age groups were examined by duplex to define the normal values of the ITA, and 55 patients (mean age 63 +/- 10 years, 48 men, 7 women) were evaluated after MIDCAB-surgery to describe the postoperative modification of the Doppler curve. The examinations were performed using a 4 - 7 MHz linear ultrasound transducer in the right and left 1. or 2. intercostal space parasternally. RESULTS: In all 96 people, the ITA was detectable on both sides presenting a typical bi- or triphasic Doppler flow profile. A linear age dependent increase in the LD of 1.95 +/- 0.15 mm (right ITA) and 1.93 +/- 0.27 mm (left ITA) respectively to 2.65 +/- 0.48 mm and 2.55 +/- 0.43 mm was found. No significant side difference was found for Vs and Vd, nor were there any age dependent differences for Vs. The SDR showed an age dependent linear increase on the right side from 3.5 +/- 1.1 to 6.1 +/- 2.2, p < 0.0012, and on the left from 3.9 +/- 1.2 to 6.7 +/- 1.7, p < 0.0001. Postoperatively, the Doppler spectrum was modified into a mono- or biphasic Doppler curve with a reduced Vs and an increased Vd resulting in a significantly decreased SDR on the left side compared with the right side (1.3 +/- 0.8 vs. 5.4 +/- 2.0, p < 0.00001). Three patients with angiographically proven graft failure had an SDR of 2.6 - 5.2 (mean 3.8), as opposed to a value of < 2.0 in case of a patent bypass. An SDR > 2.0 has a sensitivity of 100 % and a specificity of 97 % in the detection of a haemodynamically relevant (>70 %) ITA-graft-stenosis. CONCLUSIONS: With rising age, there is an increase in the LD of the ITA and the peripheral resistance, expressed as SDR. After MIDCAB surgery the former triphasic Doppler flow curve changes into a mono- or biphasic curve corresponding to the coronary blood flow. An SDR >2.0 is a strong indicator of bypass failure.

Adolescent↗
PubMed2002

[Duplex ultrasound for follow-up examination after stent-angioplasty of ostial renal artery stenoses].

AIM: Renal artery stenosis (RAS) may lead to deterioration of renal function and/or hypertension. Stent angioplasty has become the method of choice in the treatment of atherosclerotic ostial RAS. We describe the changes of the following duplex parameters: intrarenal resistance index RI according to Pourcelot and the renal-aortic flow velocity ratio (RAR) directly after intervention and during follow-up (FU). We also examine the value of the method in detecting restenosis. PATIENTS AND METHODS: We present the results of a prospective study of 241 patients with stent angioplasty for the treatment of 355 severe RAS (extent of stenosis >/= 70 % of vessel diameter). Duplex examinations during FU were performed before discharge, after 6 and 12 months, and then annually resulting in 1292 examinations. RESULTS: RAR could be calculated in 98.9 % (1278/1292), RI was calculated in 100 % of the examinations. The RAR decreased significantly from 5.9 +/- 2.1 to 1.2 +/- 0.4 after intervention (p < 0.00001) with a slight increase during follow-up. RI increased significantly from 0.64 +/- 0.11 to 0.74 +/- 0.06 after intervention (p < 0.00001), equalling the RI of the contralateral side (0.74 +/- 0.07). During a mean FU of 27 +/- 15 months, 37 restenosis (10.4 %) and 12 re-restenosis were detected and confirmed angiographically, resulting in 48 reinterventions. In case of restenosis, RAR increased from 1.3 +/- 0.4 to 6.3 +/- 2.8 (p < 0.001) with a decrease to 1.3 +/- 0.6 after reintervention (p < 0.001), and RI decreased from 0.75 +/- 0.08 to 0.64 +/- 0.11 (p < 0.001) with an increase to 0.75 +/- 0.07 after reintervention (p < 0.001). CONCLUSIONS: Duplex ultrasound is a reliable method for FU of patients after renal artery stent-angioplasty and for detecting restenosis.

Adult↗
PubMed2002

[Long-term results after recanalization of acute and subacute thrombotic occlusions of the infra-aortic arteries and bypass-grafts using a rotational thrombectomy device].

BACKGROUND: Evaluation of the acute and long-term results after recanalization of thrombotic occlusions of infra-aortic native arteries, stented arteries and bypass-grafts using a rotational thrombectomy device (8F Straub-Rotarex TM). MATERIALS AND METHODS: From July 2000 to February 2002, in 98 patients (64 % male, mean age 66 +/- 9 (range 47 to 90) years, mean duration of occlusion 31 +/- 33 (range 0 to 140) days, mean occlusion length 21 +/- 11 [range 2 to 40] cm) 100 vessel recanalizations were performed. 42 % of the interventions were performed during the first 14 days after the onset of the symptoms (acute occlusions). These patients were classified according to the after the TASC protocol modified SVS/ISCVS-classification: Class I: n = 22 (52 %); class lla: n = 13 (32 %); class llb: n = 6 (14 %); class III: n = 1 (2 %). Subacute and chronic occlusions were classified according to Rutherford (58 %): Stage 1: n = 5 (9 %); stage 2 and 3: n = 39 (68 %); stage 4: n = 6 (10 %); stage 5: n = 8 (13 %). RESULTS: Primary success rate was 96 % (ipsilateral interventions 99 %, cross-over 40 %). The restenosis rate after a mean follow-up of 13 +/- 4 months was 33 % for native arteries (group 1), 74 % for instent-recanalizations (group 2) and 86 % for bypass-graft occlusions (group 3). 3 % severe complications occurred: two amputations below the knee after unsuccessful recanalizations of a native artery and a bypass-graft, respectively. One death because of multiorgan failure in patient who was already in cardiac shock before the successful intervention. Further 16 complications could be solved periinterventionally. The ancle-brachial index was significantly improved during follow-up (from 0.37 +/- 0.19 to 0.82 +/- 0.22 before discharge, 0.70 +/- 0.21 after 12 months, p < 0.001). CONCLUSION: The Straub-Rotarex TM device is useful in the treatment of acute and subacute thrombotic occlusions of infra-aortic arterial and bypass-graft occlusions, with promising long-term results in native vessels but unchanged high restenosis of stented arteries and bypass-grafts.

Acute Disease↗
PubMed2001

[Color duplex ultrasound imaging of renal arteries and detection of hemodynamically relevant renal artery stenoses].

AIM: Although colour coded Doppler ultrasound (CCDU) is established as a non-invasive diagnostic tool for detecting renal artery stenoses (RAS), no uniform criterion for defining a hemodynamically relevant stenosis (i.e. angiographic stenosis of > or = 70% of the diameter) exists. We therefore investigated the predictive value of the renal-aortic flow-velocity ratio (RAR) > 3.5 m/s and a difference of < 0.05 between the left and right side for the resistance index according to Pourcelot (dRI) in the detection of a relevant RAS. PATIENTS AND METHODS: We analysed 500 consecutive CCDU examinations of patients with hypertension retrospectively. An RAR > 3.5 and/or a lateral inequality of the RI < 0.05 were used as stenosis criterion. RESULTS: In 448 patients (90%) both renal arteries could be found, in 11 patients (2%) only the right artery, in 6 patients (1%) the left artery, and in 35 patients (7%) no renal artery was detectable. In 98 patients (19.6%), RAS was diagnosed, 69 (71%) of them underwent angiography. 38 patients presented an RAR > 3.5 plus dRI > 0.05. In 29 of these, angiography was performed. 96% of them presented with an RAS of > or = 70% and 4% showed an RAS of 40-69% (specificity 97%, sensitivity 76%). In 54 patients the RAR was > 3.5, but dRI < 0.05. 24% of the patients undergoing angiography (n = 37) presented with an RAS of > or = 70%, 68% with an RAS of 40-69%, and 8% with an RAS of < 40% (specificity 60%, sensitivity 100%). 44 hypertensive patients who underwent angiography after a CCDU examination not suggesting the presence of RAS were used as control group. CONCLUSION: An experienced physician using a high quality colour-coded duplex-machine can reliably detect the renal arteries. The presence of RAS can be diagnosed with certainty by CCDU applying the criterion of RAR > 3.5, but the diagnosis of a one-sided haemodynamically relevant RAS can only be certain if the criterion of dRI > 0.05 is used in addition.

Aorta, Abdominal↗
PubMed2001

[The Straub-Rotarex thrombectomy system: initial experiences].

BACKGROUND: To evaluate the efficacy, safety and limitations of a new rotational thrombectomy device (Straub-Rotarex) in clinical practice. MATERIAL AND METHODS: The Straub-Rotarex catheter is a new, wire-guided rotational thrombectomy device for the treatment of acute and subacute occlusions of the femoro-popliteal arteries. Over a 6-month period, 28 patients (64% male, mean age 69 +/- 9.5, 51-91 years) with 31 legs, mean duration of occlusion 4.4 +/- 4 (0-20) weeks, mean occlusion length 22 +/- 11 (5-40) cm were treated with the device, 5 of them in a cross-over technique. Target lesions: Aortic-femoral bypass, common iliac artery, external iliac artery, common femoral artery: 1 each, superficial femoral artery: 23, popliteal artery: 17. Initial stage of claudication: IIa: 6%, IIb: 72%, III: 16%, IV: 6%. RESULTS: Primary success rate: 90% (ipsilateral: 100%, cross-over: 40%). Stage of claudication after intervention: I: 85%, IIa: 7%, III: 4%, IV 4%, one amputation. 3-months follow-up: stage I: 86% (n = 24), IIa: 14% (n = 4), one femoro-popliteal bypass. Restenosis rate 18%. 6-months follow-up: stage I: 56% (n = 9), IIa: 31% (n = 5), IIb: 13% (n = 2). Restenosis rate 56%. COMPLICATIONS: 32% (5 perforations, three cases of embolism after PTA, one wire-induced dissection, one retroperitoneal bleeding coming from the puncture site). CONCLUSIONS: The new device is a useful tool for the treatment of (sub)acute long-distance occlusions of the SFA and popliteal artery and in-stent restenosis as well in antegrade technique. Main complications are perforations. Cross-over interventions can only be done in special cases.

Aged↗
PubMed2001

Specific nucleoprotein complexes within adenovirus capsids.

Adenoviral DNA was examined within capsids by dimethyl sulfate footprinting. Protein-DNA interactions were visualized through ligation-mediated PCR (LM-PCR). Signals for protein binding were found adjacent to both inverted terminal repeats (ITR). There were no indications of close protein binding at several other loci of the viral genome. Therefore, adenovirus type 5 seems to contain sequence- or locus-specific DNA binding proteins within the virion.

Adenoviridae↗
PubMed2000

Structure-function analysis of the dolichyl phosphate-mannose: protein O-mannosyltransferase ScPmt1p.

Protein O-mannosylation is an essential protein modification. It is initiated at the endoplasmic reticulum by a family of dolichyl phosphate-mannose:protein O-mannosyltransferases (Pmts), which is evolutionarily conserved from yeast to humans. Saccharomyces cerevisiae Pmt1p is an integral membrane protein of the endoplasmic reticulum. ScPmt1p forms a complex with ScPmt2p that is required for maximum transferase activity. Recently, we proposed a seven-transmembrane structural model for ScPmt1p. A large, hydrophilic, endoplasmic reticulum-oriented segment is flanked by five amino-terminal and two carboxyl-terminal membrane-spanning domains. Based on this model, a structure-function analysis of ScPmt1p was performed. Deletion mutagenesis identified the N-terminal third of the transferase as being essential for the formation of a functional ScPmt1p-ScPmt2p complex. Deletion of the central hydrophilic loop eliminates mannosyltransferase activity, but not ScPmt1p-ScPmt2p interactions. Alignment of all fully characterized PMT family members revealed that this central loop region contains three highly conserved peptide motifs, which can be considered as signatures of the PMT family. In addition, a number of invariant amino acid residues were identified throughout the entire protein sequence. In order to evaluate the functional significance of these conserved residues site-directed mutagenesis was performed. We show that several amino acid substitutions in the conserved motifs significantly reduce ScPmt1p activity. Further, the invariant residues Arg-64, Glu-78, Arg-138, and Leu-408 are essential for ScPmt1p function. In particular, Arg-138 is crucial for ScPmt1p-ScPmt2p complex formation.

Amino Acid Sequence↗
PubMed1992

Injuries in paragliding.

In a retrospective study, 376 paragliding accidents have been analysed. Leg injuries were most common, but a large number of spinal injuries also occurred. The causes were either misjudgement by the pilot or the influence of weather and terrain. Improvements in the instructor's knowledge and the pilot's training could have prevented most of the accidents. Analysis of the mechanisms of the crashes and the pattern of trauma help to produce an efficient approach to diagnosis and treatment.

Accidents, Aviation↗
PubMed1990

[Hanggliding--the Icarus syndrome].

Parasailing is a new sport resulting in an increasing number of severe injuries. The analysis of 152 accidents reveals typical trauma mechanisms for the different flight positions. 87 patients (57%) had their crash during the landing approach. 68 pilots (45%) were affected during their primary training course. Spine lesions were found in 30 patients. Lower limb injuries occurred in 44 cases. Detailed trauma evaluation can give a clue for systematic prophylaxis.

Accidents, Aviation↗
PubMed1989

Monitoring of the inflammatory response in early peritonitis.

The inflammatory response which is similar in all forms of peritonitis was recorded by determining the levels of parameters shown to represent the activation state of plasmatic and cellular systems as well as the inhibitory capacity of the plasma. In a selected series of patients with different underlying diseases, blood sampling was started at the time of admission when the clinical finding of an acute abdomen led to emergency laparotomy. Depending upon the duration of the illness and the severity of the peritonitis, a significant increase in fibrinopeptide A and of C3a could be detected within a few hours, which was followed by an increase in the elastase alpha-1-proteinase inhibitor complex. Differences due to variable cause could not be found. There was a striking correlation between the preoperative values of these three parameters and the postoperative course of the patients. Additionally, there was a significant enhancement of an endothelial proliferation-inhibiting capacity in the serums of the lethal group, whereas endotoxin could only be detected in trace amounts in four patients with intraabdominal infection in the preoperative period.

Adult↗