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S Hutschenreiter

Publications and source records attributed to S Hutschenreiter.

At least 19 recordsLinked to original sources
PubMed2001

Molecular mechanism and structural aspects of transporter associated with antigen processing inhibition by the cytomegalovirus protein US6.

The human cytomegalovirus (HCMV) has evolved a set of elegant strategies to evade host immunity. The HCMV-encoded type I glycoprotein US6 inhibits peptide trafficking from the cytosol into the endoplasmic reticulum and subsequent peptide loading of major histocompatibility complex I molecules by blocking the transporter associated with antigen processing (TAP). We studied the molecular mechanism of TAP inhibition by US6 in vitro. By using purified US6 and human TAP co-reconstituted in proteoliposomes, we demonstrate that the isolated endoplasmic reticulum (ER)-luminal domain of US6 is essential and sufficient to block TAP-dependent peptide transport. Neither the overall amount of bound peptides nor the peptide affinity of TAP is affected by US6. Interestingly, US6 causes a specific arrest of the peptide-stimulated ATPase activity of TAP by preventing binding of ATP but not ADP. The affinity of the US6-TAP interaction was determined to 1 microm. The ER-luminal domain of US6 is monomeric in solution and consists of 19% alpha-helices, 25% beta-sheets, and 27% beta-turns. All eight cysteine residues are involved in forming a stabilizing network of four intramolecular disulfide bridges. Glycosylation of US6 is not required for function. These findings point to fascinating mechanistic and structural properties, by which specific binding of US6 at the ER-luminal loops of TAP signals across the membrane to the nucleotide-binding domains to prevent ATP hydrolysis of TAP.

ATP-Binding Cassette Transporters↗
PubMed1993

[Long-term results of percutaneous transluminal angioplasty and stent implantation in venous stenoses following transfemoral thrombectomy].

Thirty consecutive patients were operated on for iliofemoral venous thromboses. In each case, a transfemoral thrombectomy was performed and an arterio-venous fistula was created. Three to six months later, a cross-over arterio-venography revealed 10 severely stenosed venous segments in 8 patients (common iliac vein 4, external iliac vein 3, common femoral vein 3). All stenoses were treated by percutaneous transvenous angioplasty (PTA). Six times a flexible, self-expanding Wallstent was placed within the stenosis after dilation (PTA+S). Complications did not occur. Median follow up was 17 months (3-23 months). PTA+S proved superior (4/6 excellent results) when compared to PTA alone (1/4 excellent result), because of frequent restenosis after the latter. Minor results following PTA+S were caused by intimal hyperplasia within the stent, when the av-fistula was kept patent for more than a year after stent placement.

Adolescent↗
PubMed1992

[Stent-supported percutaneous therapy of iliac vein stenosis following operative thrombectomy and placement of a shunt].

Among 15 patients with acute thrombotic disease of pelvic veins who had been submitted to operative thrombectomy and creation of arteriovenous fistula in the groin, 12 presented with stenotic lesions 3 months later. These stenoses were submitted to percutaneous angioplasty. If angioplasty failed, percutaneous placement of a vascular stent (wall stent) was performed immediately (n = 7). Stenting in cross-over-technique proved practicable in all cases. Secondary stenotic disease in the exclusively dilated area was observed in 3/5 cases and was also treated with a wall stent. In one patient with recurrent stenoses who refused stenting, extended thrombosis occurred after occlusion of the AV-fistula. At mid-term PTA was successful in only two cases. Intimal hyperplasia was observed in only one wall stent treated patient. Percutaneous treatment of iliacal stenoses in patients with postthrombotic syndrome may be performed safely under the protective effect of the fistula. With the presented technique, patency of pelvic veins could be restored in 11/12 patients with postoperative significant venous stenoses.

Adult↗
PubMed1992

[Giant cell arteritis of the arteries of the arm. Diagnosis, surgical indications and choice of procedure].

At autopsy, affection of the aortic arch and of the arm arteries is found in about 70% of patients with giant cell arteritis. Symptoms occur in only about 5% of them. Arteriography often shows typical spindle-shaped stenoses or tapered occlusions of the diseased vessels. Arterial stenoses are successfully treated with corticosteroids. In case of chronic occlusion, however, ischemia-induced symptoms may necessitate an operation. Endarterectomy should be preferred to bypass procedures. Subsequent long-term corticosteroid treatment should be instituted in order to treat the underlying disease, and to prevent reocclusions.

Aged↗
PubMed1990

[A new variant of the popliteal artery compression syndrome].

The authors describe a new variant of the popliteal artery across the lateral head of the gastrocnemius muscle. Therefore a new more simple classification is proposed: type I-III. A further differentiation in subgroups as Ia, IIa according to Insua has no clinical value. A posterior approach to the popliteal artery gives a detailed view of the anatomic structures such as muscle and band origin. A medial incision should be chosen if crural reconstruction is expected.

Aneurysm↗
PubMed1990

Morphological characterization of carotid artery stenoses by ultrasound duplex scanning.

Ulcerations and intraplaque hemorrhages are thought to play an important role in the development of neurological deficits in carotid artery stenoses. To assess the ability of duplex scanning to predict plaque morphology we compared different sonographic criteria (plaque border, plaque density, plaque structure) with the morphological findings in 169 consecutive carotid endarterectomies (144 cases with diameter reduction greater than 50%). Two percent of the sonograms were inadequate, and 20% showed poor image quality. Regular plaque borders revealed a smooth or at most minimally ulcerated surface in 92%. Grossly ulcerated stenoses, however, were only found in 27% of the irregular plaques. Moreover, the plaque border was nonvisible in 35% of all cases. Simple, fibro-atheromatous plaques were found to be echogenic in 72% and echolucency was present in 80% of the stenoses with relevant intraplaque hemorrhage. In conclusion, duplex scanning proved to be capable of detecting smooth, fibro-atheromatous stenoses with high accuracy. Ulcerations, however, cannot be predicted reliably, and intraplaque hemorrhage cannot be differentiated from atheromatous debris.

Carotid Arteries↗
PubMed1988

Early detection and differentiation of periprosthetic fluid accumulation after vascular reconstructive surgery.

Ultrasonographic duplex scanning is used widely to screen the abdominal arterial system and to detect lesions in the extracranial cerebral arteries. Based on clinical studies of 11,712 vascular reconstructions, this report describes the early recognition of fluid accumulation around vascular prostheses. The clinical examination may suggest the typical complications that arise after vascular surgery such as hematoma, pseudoaneurysm, lymphocele, abscess, or perigraft cyst. Duplex scanning, combined with puncture and aspiration, proved to be of great benefit in differentiating the specific type and extent of the complication. Special attention is paid to the so-called perigraft reaction, thought to be a result of an aseptic biological incompatibility to synthetic vascular grafts. It is emphasized that ultrasonographic routine follow-up after vascular surgery is essential for early diagnosis, especially since each complication suspected requires specific therapeutic treatment to prevent exacerbation because of inadequate treatment.

Abscess↗
PubMed1988

[Mesenterial infarct. New aspects of diagnosis and therapy].

Based on a retrospective analysis of 38 patients with mesenteric ischemia treated from 1981-1987, the current diagnostic and therapeutic concepts are presented. Embolic or thrombotic occlusions of the superior mesenteric artery prevailed (34 patients); venous thrombosis (4 patients) and non-occlusive disease (2 patients) occurred less frequent. Old age (70.6 years in average) and a long time interval between onset of symptoms and therapy (25.8 h in average) are responsible for the still high operative mortality (52.9% in the reported series). Of crucial importance is the early diagnosis within the first 6-12 hours, in which the ischemic bowel may mostly retain its viability. Since the application of transfemoral selective angiography or primary laparotomy however far more patients can be cured, compared to the results in earlier days. Especially in case of primary laparotomy the operative strategy aims in the exposition and inspection of the main trunk of the superior mesenteric artery and vein. Extensive ischemia of the intestines mandates, first of all, revascularization of the bowels. By means of exclusive vascular reconstruction or in combination with limited bowel resection (15 patients) the operative mortality could be reduced to 20%. For the intraoperative determination of intestinal viability the fluorescein test is of high reliability. New concepts in the management of mesenteric ischemia such as local arterial application of thrombolytics or spasmolytics open new approaches to improve the therapeutic results. Post-operative monitoring of serum-lactate in combination with clinical findings obviates routinely performed second-look operation.

Adult↗
PubMed1988

[Reconstructive interventions of the inferior vena cava].

Reconstructive procedures have superceded the lower vena cava ligature. Especially in cases of vena cava thrombosis, surgical reconstruction requires a different procedure depending on the origin, extent, and age of the thrombus. Currently even the new improved prosthetic materials used for alloplastic vena cava replacement may not replace the temporary av-fistula. Vena cava lesions demand immediate repair via a ventral transperitoneal access and reconstruction instead of ligature.

Adolescent↗
PubMed1987

[Determination of the degree of stenosis in carotid artery stenoses: ultrasound and i.v. DSA in comparison to surgical findings].

The specimens from 116 consecutive carotid thrombendarterectomies were taken as "gold standard" to evaluate the accuracy of ultrasound methods (duplex scanning + extra-/transcranial Doppler sonography) and intravenous digital subtraction angiography (i.v. DSA) in carotid artery stenoses. In 65 cases, in which the specimens could be gauged reliably, sonography estimated the degree of stenosis in 85% within a range of +/- 10%, in 97% within +/- 20% i.v. DSA was accurate in 52 respectively in 94%. High-grade stenoses were correctly assessed by ultrasound in 90%, by i.v. DSA in 64%. Sonography identified 4/10 kinkings and coilings of the carotid artery, i.v. DSA 9/10. Current available ultrasound methods enable estimation of the diameter reduction of carotid artery stenoses with low deviations. I.v. DSA seems to be less reliable, but can be used favourably as a complementary method to sonography.

Carotid Artery Diseases↗
PubMed1987

Advances in vascular endoscopy.

In reconstructive vascular surgery several intraoperative investigations are in use to check-up and secure full blood flow restoration (angiography, ultra-sound, electro-magnetic flowmeter etc.). In the last years endoscopical lumen control, introduced 1969 in clinical praxis, could be remarkably simplified and improved. For vascular endoscopy three technical prerequisites are necessary: a) temporary interruption of blood flow using clamps or balloon catheters, b) replacement of the blood by a transparent medium via pressure controlled saline perfusion, c) availability of suitable special endoscopes. The main application of vascular endoscopy includes: a) semi-closed thromboendarterectomy (aorto-iliac or femoropopliteal), b) arterial embolectomy, c) lumen control of inserted grafts including the anastomosis and the distal run-off vessels, d) venous thrombectomy. The availability of small-calibre endoscopes (external diameter: 1.7-2.7 mm) enables the extension of lumen control to small vessel areas such as the tibial and coronary arteries. Compared with angiography vascular endoscopy offers several convincing advantages such as a more reliable three dimensional lumen control, easy performance, saving time and the avoidance of any additional X-ray exposure. Technical faults or overlooked concomitant vascular lesions can be diagnosed and corrected immediately.

Angiography↗
PubMed1986

[Surgical therapy of thrombosis of pelvic and leg veins].

The late results of venous thrombectomy could be remarkably improved by routine use of intraoperative vascular endoscopy and additional temporary a.v.-fistula. Long-term follow-up (mean 8 y.) of 119 patients (Ulm 1970-1983) showed full patency in 75% (phlebography) and very good function in 63% (phlebodynamometrie). With improved surgical technique the preservation of values is possible. Mortality was 1,8% and the incidence of clinically relevant postoperative pulmonary embolism was lower than 2%.

Arteriovenous Shunt, Surgical↗
PubMed1985

Intravenous digital subtraction angiography in patients with femoral arteriovenous fistulas and ilio-iliac crossover graft.

Fourteen patients with femoral arteriovenous (AV) fistulas and ilio-iliac crossover bypass grafts after postthrombotic occlusion of an iliac vein were studied by intravenous digital subtraction angiography (IV DSA). Digital radiography's utility may be evaluated in the demonstration of the vascular status of AV fistulas and venous return through the reopened iliac vein or ilio-iliac graft. Digital subtraction imaging is a suitable modality to plan operations, such as closure of temporary AV fistula. In follow-up studies of these cases, patency of the crossover bypass can be assessed by noninvasive DSA of the ascending veins.

Adolescent↗
PubMed1985

[Aortofemoral bifurcation bypass--effect of the anesthesia procedure (NLA, thoracic continuous catheter peridural anesthesia) on circulation, respiration and metabolism. Intraoperative circulatory reactions].

51 patients who were selected for aorto-bifemoral bypass operation (infrarenal aortic aneurysm, iliac or iliofemoral occlusive disease) were randomized into two groups. 26 patients were operated on under neuroleptanaesthesia and 25 patients had a continuous thoracic epidural, which was supplemented with a light general anaesthesia during the operation. All patients were optimally volume loaded prior to surgery. The most marked haemodynamic alterations (tachycardia, arterial hypertension, increase of cardiac index, left ventricular stroke work index and cardiac minute work) were provoked by eventration of the gut. In the epidural group, these changes were attenuated and in contrast to the neuroleptanaesthesia group, there were a few patients who had a serious fall in blood pressure. These reactions were regularly accompanied by a generalized flush which led to the hypothesis that they were caused by the release of intestinal hormones, reactive peptides and neurotransmitters, from the mechanically irritated gut. Clamping of the aorta was relatively uneventful. Heart rate and cardiac index decreased in both groups but mean arterial pressure and pulmonary capillary wedge pressure remained stable. Systemic vascular resistance increased slightly in the neuroleptanaesthesia, but not in the epidural group. Declamping was followed by significant but transient falls in systemic vascular resistance and arterial pressure in both groups, despite sufficient volume loading before opening the clamp. In the neuroleptanaesthesia group these changes spontaneously returned to normal; in the epidural group 6 patients received vasopressors or positive inotropic drugs. These results indicate the following: Epidural anaesthesia prevents hypertension and tachycardia and lowers cardiac minute work. Eventration of the gut, acute blood losses and declamping of the aorta may be critical situations, which can lead to profound hypotension. Under neuroleptanaesthesia eventration of the gut is followed by tachycardia and hypertension whereas blood losses and declamping are not as critical as when an epidural is used. Only experienced anaesthetists should use epidural anaesthesia for aortic surgery. An intensive monitoring of haemodynamic function during this form of anaesthesia is mandatory.

Adult↗