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Biomedical subjects

S Ernst

Publications and source records attributed to S Ernst.

At least 19 recordsLinked to original sources
PubMed2006

[New therapy possibilities for arrhythmias using catheter ablation].

Radiofrequency current ablation has been developed over the last 20 years to be the standard approach for treating tachycardia by catheter ablation. By combining new 3-D imaging technology (CT and MRI) with 3-D electrophysiologic mapping systems, a new tool has been created to display the cardiac activation sequence of the individual. These technologies are extremely important for the treatment of complex arrhythmias such as the catheter ablation of atrial fibrillation. Instead of the conventional "point by point" linear ablation procedure, balloon catheters have been applied to a circumferential linear lesion in a "single shot" procedure using, for example, cryothermia, ultrasound or laser energy. Finally, magnetic navigation is a new steering tool for performing ablation procedures, leading to reduced exposure to ionizing radiation.

Atrial Fibrillation↗
PubMed2006

[Simultaneous rupture of a patellar tendon and contralateral quadriceps tendon].

The simultaneous bilateral rupture of the quadriceps tendon is a rare injury; only occasional reports exist about the bilateral simultaneous rupture of the patellar tendon. Degenerative changes of the tendon due to drugs or diseases lead to the rupture. We describe two cases of simultaneous rupture of the patellar and contralateral quadriceps tendons; only one patient had special risks. We report the management of therapy and the functional results using the Lysholm score and Knee Rating Scale.

Adult↗
PubMed2006

[Recurrent pulmonary embolism in cases of popliteal vein aneurism].

Aneurysms of the popliteal vein usually occur within the context of angiodysplastic syndromes. The first symptom of an isolated aneurysm may be pulmonary embolism. Recurrent pulmonary embolism without thrombophilia requires more specific diagnostics. The rate of recurrent pulmonary embolism is high when no therapy is applied. Surgical treatment results in healing.

Aneurysm↗
PubMed2004

Agonist-induced trafficking of the low-affinity formyl peptide receptor FPRL1.

The formyl peptide-like receptor FPRL1 is a member of the chemoattractant subfamily of G protein- coupled receptors involved in regulating leukocyte migration in inflammation. To elucidate mechanisms underlying the internalization of ligand-bound FPRL1 and possible receptor recycling, we characterized the endocytic itinerary of FPRL1. We show that agonist-triggered internalization from the plasma membrane into intracellular compartments is prevented by perturbation of clathrin-mediated endocytosis, such as expression of the dominant-negative clathrin Hub mutant, siRNA-mediated depletion of cellular clathrin and expression of a dominant-negative mutant of the large GTPase dynamin. Internalized FPRL1 co-localized with endocytosed transferrin and the small GTPases Rab4 and Rab11 in vesicular structures most resembling recycling endosomes. Recycling of FPRL1 was significantly reduced by pretreatment with PI3-kinase inhibitors. Thus, ligand-bound FPRL1 undergoes primarily clathrin-mediated and dynamin-dependent endocytosis and the receptor recycles via a rapid PI3-kinase-sensitive route as well as pathways involving perinuclear recycling endosomes.

Chromones↗
PubMed2003

[Reconstruction of the inferior vena cava for extended resection of malignant tumors].

OBJECTIVES: Malignant tumor invasion in the inferior vena cava (IVC) has for a long time been the limiting factor in the resection of retroperitoneal tumors. The clinical outcome in these patients depends on vascular surgical techniques, the central role of which is played by IVC reconstruction. METHODS: Within the last 7 years, 9,085 vascular reconstructive procedures were performed in our department. Six patients suffered from retroperitoneal invasion of tumor into the IVC. After tumor resection, the involved IVC segments were replaced by polytetrafluorethylene (PTFE) grafts to restore IVC continuity. In three patients, an adjunctive arteriovenous (AV) fistula was constructed. RESULTS: The graft patency after a mean follow-up of 30.2 months (range 1 to 79) was 83.3%. The only graft occlusion occurred in a patient without AV fistula. There were no perioperative deaths and no major complications demanding reoperation. CONCLUSION: In patients with tumor involvement of the IVC, clinical outcome depends on vascular surgical coprocedure. After resection of the IVC, a PTFE graft should be interposed in combination with an AV fistula. Anticoagulation and CT scan are recommended after 3 months before ligation of the AV fistula.

Adult↗
PubMed2003

[Proximal femur fracture with secondary hyperparathyroidism].

We rarely see trauma patients with secondary hyperparathyroidism. We report about a case of a 68-year-old African female with a pertrochanteric femur fracture after a falling accident. As a secondary result we noted a Looser zone (pseudofracture) in the fractured femur. Extended diagnostic work-up including determination of vitamin D metabolites indicated the existence of a secondary hyperparathyroidism. The dark tanned phenotype of the African patient in combination with usually less solar radiation in central Europe seems to be the causative factor for the secondary hyperparathyroidism. Thus, this resulted in reduced cutaneous vitamin D synthesis. The fracture of the proximal femur was stabilized by osteosynthesis with a gamma nail; we thereby bridged the Looser zone.

Aged↗
PubMed2003

[Conservative treatment of acute embolisms of the carotid bifurcation].

Embolic events of the carotid bifurcatin are a rare cause of cerebrovascular accidents. We observed two patients who showed a spontaneous recanalisation of an embolic occlusion of the extracranial vessels when treated with conservative procedure using heparin. Both patients had a near complete remission of the symptoms without impairment in their daily activities.

Acute Disease↗
PubMed2003

[Current diagnosis and therapy of non-occlusive mesenteric ischemia].

PURPOSE: Non-occlusive mesenteric ischemia (NOMI) is a life threatening disease. Therapy and prognosis depend upon the length of time elapsed between primary clinical manifestation and the time of definitive diagnosis and treatment. MATERIALS AND METHODS: NOMI was diagnosed by intraarterial selective angiography in four patients. After a bolus administration of 20 g Alprostadil (Prostavasin) into the superior mesenteric artery, intraarterial perfusion was continued with 60 microg Alprostadil/day via the catheter for three days. RESULTS: The mesenteric ischemia resolved in all patients. One patient recovered completely. Three patients recovered from mesenteric ischemia, but died subsequently due to complications of their primary diseases. CONCLUSION: When NOMI without perforation or necrosis of the bowel wall is suspected clinically, immediate intraarterial angiography is the diagnostic method of choice. If NOMI is confirmed, the appropriate treatment is the intraarterial application of potent vasodilators for several days. The diagnostic work-up in suspected NOMI and the impact of different radiological examinations are explained. The literature is reviewed.

Aged↗
PubMed2002

Relevance of magnetic resonance imaging for ventricular endoscopy.

OBJECTIVE: Endoscopic procedures may represent an alternative to microsurgery or shunt operations in intra- or paraventricular pathologies. However, the operative results mainly depend on the selection of suitable patients. In the present study of 30 patients with occlusive hydrocephalus, the relevance of differentiated magnetic resonance (MR) imaging for evaluation of the pathophysiological and anatomic prerequisites was investigated. PATIENTS AND METHODS: Apart from conventional axial T(2) -weighted turbo spin echo (TSE) sequences (TR/TE 2126/100 ms) and T(1) -weighted spin echo (SE) sequences (TR/TE 450/15 ms) with and without the administration of Gd-DTPA, the MR protocol included sagittal and coronal thin-sliced T(2) -weighted TSE sequences, cardiac-triggered (TR/TE > 2700/120 ms, slice thickness 3.0 mm) or in volume technique (TR/TE 4000/180 ms, slice thickness 1.4 mm). For the visualization of CSF flow, a sagittal and axial phase-contrast-multi-heart-phase (PCMHP) measurement with 16 phases per cardiac cycle and flow sensitivity in the cranio-caudal direction (TR/TE 18/9.5 ms and 14/9.5 ms) was performed. RESULTS: The combination of imaging and flow sequences provided most information about the extent and the etiology of hydrocephalus. An obstruction of CSF pathways could be detected by the absence of flow voids in T(2) -weighted TSE sequences or of flow signals in PCMHP sequences. The size of the foramen of Monro and of the third ventricle could be evaluated in thin-sliced T(2) -weighted TSE sequences, for the foramen of Monro in coronal and sagittal and for the third ventricle in coronal and axial slice direction, respectively. The basal structures of the third ventricle, including its floor, the infundibular recess, the mamillary bodies, and the basilar artery, could be best identified in sagittal thin-sliced T(2) -weighted TSE scans, cardiac-triggered or in volume technique. CONCLUSION: In occlusive hydrocephalus, a differentiated MR protocol with thin-sliced T(2) -weighted TSE sequences and phase-contrast sequences allows a very precise estimation of the pathophysiological and the anatomic prerequisites for endoscopic procedures. Furthermore, MR imaging can be used for the follow-up documentation of ventriculo-cisternostomies, -cytostomies, or openings of other membranes.

Adolescent↗
PubMed2002

[The acute mesenteric ischemia - not understood or incurable?].

PURPOSE: Despite surgical research and progress, the high mortality of acute intestinal ischemia seems to be improved insignificantly over the past fifty years. In this study we analyzed the specific diagnostic and therapeutic problems of the disease in order to improve further management of acute mesenteric ischemia. METHODS: From 1979 until 2000 64 patients (female 31, male 33) with a mean age of 64 (30-89) years underwent operation for primary intestinal ischemia at our institution. All medical and surgical records and imaging studies were reviewed retrospectively. Follow up consisted of clinical examination and duplex sonography. RESULTS: Only in 26 patients (41 %) a preoperative diagnostic work-up including angiography 12 and CT 14 was performed, whereas in 42 cases the intestinal ischemia was diagnosed during surgical exploration. Intestine malperfusion was caused primarily by venous thrombosis in 9 cases (14 %) and by arterial occlusive disease in 55 cases (86 %). Arterial disorders consisted of arterial thrombosis in 19 cases (30 %), arterial embolism in 18 cases (28 %), aortic or mesenteric artery dissection in 10 cases (15 %), non occlusive disease (NOD) in 5 cases (8 %), trauma 3 cases (5 %). Five different therapeutic strategies were applied: group I: Intestinal resection: 24 patients, anastomotic insufficiency 5 (39 %), mortality 11 (46 %), group II: intestinal artery revascularization: 5 patients, secondary patency rate 80 %, mortality 40 %, GROUP III: Intestinal artery revacularization and perfusion with Ringer's solution: 11 patients, mortality 8 (73 %), group IV intestinal artery revascularization and intestinal resection: 3 patients, mortality 100 %, group V intestinal artery revascularization and perfusion and intestinal resection: 3 patients, mortality 33 %. A second look operation was performed in 29 cases (40 %) and displayed malperfusion in 72 %. Only 21 of 64 patients survived the acute intestinal ischemia (in hospital mortality was 67 %). Delayed diagnostic and operation caused higher mortality (interval 10 hours: mortality 59 %, interval 37 hours mortality; 71 %, p = 0,06). Follow up after 61 (4-72) months of 21 patients (100 %) could be achieved. Ten patients (48 %) had meanwhile died, 5 patients (50) % as consequence of mesenteric ischemia, the others of unrelated reasons. Eleven patients are still alive without clinical signs of intestinal ischemia. CONCLUSIONS: Early diagnosis before hospitalisation and in-hospital (arteriography) and operation are essential to improve the outcome of patients with acute intestinal ischemia. To avoid short bowel syndrome bowel resection should be combined with mesenteric revascularization. Resection of malperfused bowel should be done cautiously and should be followed automatically by second look operations. Special expertise and good team work of visceral and vascular surgeons are required to achieve better therapeutic results.

Acute Disease↗
PubMed2002

Phase II trial of branched peginterferon-alpha 2a (40 kDa) for patients with advanced renal cell carcinoma.

BACKGROUND: Peginterferon-alpha 2a (40 kDa), PEGASYS(TM) (PEG-IFN), is a modified form of recombinant human interferon (IFN)-alpha 2a with sustained absorption and prolonged half-life after subcutaneous administration. A phase II trial was conducted in previously untreated patients with advanced renal cell carcinoma (RCC) to assess efficacy, toxicity and pharmacokinetic profile. PATIENTS AND METHODS: Forty previously untreated patients with advanced RCC were enrolled on this multicenter trial. The median age was 60 years and 63% had prior nephrectomy. PEG-IFN was administered at a dose of 450 micro g/week on a weekly basis by subcutaneous injection. Serial venous blood samples were drawn to assess concentrations of PEG-IFN. RESULTS: Five (13%) patients achieved a major response (four partial and one complete). The median time to progression was 3.8 months, and 63% of patients were alive at 1 year. The toxicity profile was mostly mild to moderate in intensity. Toxicity higher than grade 2 included neutropenia (six patients), fatigue/asthenia (four patients), nausea/vomiting (three patients) and elevated hepatic transaminase concentrations (four patients). Serum drug levels were studied in all patients; mean C(max) at week 1 was 19 ng/ml, and levels were sustained at close to peak over 1 week. With chronic dosing, drug concentration was increased 3-fold, and steady state was achieved in 5-9 weeks. CONCLUSIONS: The sustained maintenance of serum levels of PEG-IFN allows once-weekly dosing. The efficacy and tolerability profile was qualitatively similar to standard IFN-alpha, and adverse events were mostly mild to moderate in nature.

2',5'-Oligoadenylate Synthetase↗
PubMed2001

pH-induced structural changes regulate histidine decarboxylase activity in Lactobacillus 30a.

Histidine decarboxylase (HDC) from Lactobacillus 30a produces histamine that is essential to counter waste acids, and to optimize cell growth. The HDC trimer is active at low pH and inactive at neutral to alkaline pH. We have solved the X-ray structure of HDC at pH 8 and revealed the novel mechanism of pH regulation. At high pH helix B is unwound, destroying the substrate binding pocket. At acid pH the helix is stabilized, partly through protonation of Asp198 and Asp53 on either side of the molecular interface, acting as a proton trap. In contrast to hemoglobin regulation, pH has a large effect on the tertiary structure of HDC monomers and relatively little or no effect on quaternary structure.

Binding Sites↗
PubMed2001

[Real-time compound imaging: improved visibility of puncture needles and localization wires as compared to single-line ultrasonography].

AIM: To compare the visibility of biopsy needles and localization wires using real-time compound imaging (SonoCT) and single-line ultrasound (SLU). METHODS: 14-18 G biopsy needles and 5 different localization wires with and without puncture needle were placed into cadaverous muscle in 4 different angulations (0, 12, 18 and 25 degrees). Sonography was performed with an ATL HDI 5000 sonography device with a 5-12 MHz linear array using single-line ultrasound and compound imaging with 3 and 9 frames (Comp3 and Comp9) from different viewing angles. Images of the needles were obtained in the longitudinal plane without changing depth, focus position, and gain settings between the measurements. The mean grey values of the needle (gv_n) and of the background (gv_b) were obtained from histograms. Contrast was calculated using the equation (gv_n-gv_b)/gv_b + gv_n). Mean contrast in single-line and compound images was compared for each angulation using a Student t-test. RESULTS: The mean contrast at 0 degree was 0.686 in single-line ultrasound. This was significantly higher than in Comp3 (0.62) and Comp9 (0.633) (p < 0.05) images. At 12 degrees no significant differences could be observed. At 18 degrees image contrast was significantly higher in compound images with 0.493 (Comp3) and 0.498 (Comp9), compared to SLU (0.433) (p < 0.05). At 25 degrees the difference between compound images (Comp3: 0.394; Comp9: 0.402) and SLU (0.306) was greatest (p < 0.0001). CONCLUSION: At 0 degree and 12 degrees visibility is very good for all tested materials. For steeper angulations contrast was partly critical in SLU and significantly enhanced with compound imaging. Thus, SonoCT may be useful to increase precision of ultrasound-guided percutaneous interventions.

Animals↗