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Biomedical subjects

D Abendroth

Publications and source records attributed to D Abendroth.

At least 37 records · Page 2Linked to original sources
PubMed1997

Stenting of central venous stenoses in hemodialysis patients: long-term results.

From November 1992 through July 1996, 15 Wallstents were implanted for the treatment of symptomatic central arm vein obstructions in 14 hemodialysis patients (10 subclavian, 2 brachiocephalic vein stenoses, 2 subclavian vein occlusions). There were no acute complications. All patients were investigated by clinical examination and color-duplex sonography at regular three month intervals. When recurrent swelling predicted restenosis, phlebography was also performed. During the follow-up, high grade stenoses at the central or peripheral ends of four stents were successfully treated with five overlapping stents, giving a total of 20 Wallstent implantations. Complete occlusion of another subclavian vein distally to the stent at 16 months required ligation of the patient's arteriovenous fistula. Life table analysis including all 20 stents revealed a cumulative primary one year (two year) stent patency of 70% (50%). The cumulative secondary one year (two year) stent patency was 100% (85%). We believe that in hemodialysis patients, PTA plus Wallstent implantation is a safe and effective procedure in the treatment of central venous stenoses and even shorter occlusions. Consequent follow-up allows for timely diagnosis and treatment of restenoses, thus guaranteeing long-term patency rates comparable to those of veno-venous bypass surgery.

Constriction, Pathologic↗
PubMed1996

Na-K/2Cl transporter inhibition for reduction of postischemic kidney failure tested in autologous reperfusion.

Postischemic kidney function may be influenced by donor conditioning. The sulfamoyl-benzoate "piretanide" (P) is a diuretic agent with an inhibitory effect on the luminal Na-K-2CL-transporter system in the ascending part of the loop of Henle. A clinical pilot study demonstrated a lower rate of organ dysfunction following transplantation in humans when the donor organs were pretreated with piretanide. In an experimental ex vivo model the effect of piretanide on immediate organ function following long or short cold ischemia was studied. Porcine kidneys (n = 36) were removed after in situ transaortal hypothermic flushing with 21 Eurocollins solution. Following short storage (1 h, n = 18) or long storage (24 h, n = 18) the kidneys were reperfused with intraoperatively drawn heparinized autologous blood diluted with Ringer's lactate to a hematocrit of 25%. Urine flow was higher in the piretanide-pretreated group (p), especially after long storage. The electrolyte loss was comparable in both groups. Postischemic endogenous creatinine clearance was significantly elevated in the treatment group (4.45 +/- 0.6 ml/min per 100 mg in P vs 1.91 +/- 0.4 ml/min per 100 mg, in control, P < 0.05 Mann-Whitney test). Renal hemodynamics were improved by piretanide, resulting in significantly lower resistance and allowing higher flow during pressure-controlled perfusion. O2 consumption, representing general metabolic activity, was higher after long storage, indicating an earlier recovery from cold ischemia. In this ex vivo model, autologous reperfusion of porcine kidneys could be improved by piretanide pretreatment. Autoregulation of kidney vasculature was maintained as well as functional parameters such as creatinine clearance or gluconeogenesis. Therefore, piretanide may be used in larger clinical trials to further improve organ quality in times of donor shortage.

Animals↗
PubMed1996

Expression of human decay accelerating factor (hDAF) in transgenic pigs regulates complement activation during ex vivo liver perfusion--immunopathological findings.

Ex vivo perfusions of human decay accelerating factor-expressing transgenic (n = 3), and nontransgenic (n = 6) porcine livers with human blood revealed a higher degree of organ damage in non-transgenic pig livers. Transgenic livers were protected from immunohistologically detectable complement deposition, despite corresponding IgM and IgG deposits in both groups. Complement activation and consumption of C3 and C4 turned out to be lower in transgenic pig livers. In contrast to livers of normal landrace pigs, livers from genetically manipulated pigs showed no morphological alterations after perfusion.

Animals↗
PubMed1996

The function of transgenic human DAF-expressing porcine livers during hemoperfusion with human blood.

Extracorporal pig liver perfusion could bridge the deadly problem of acute human liver failure. However, preformed natural antibodies and complement activation (CA) are the predominant mechanisms of hyperacute xenogeneic rejection. The blockade of both pathways of CA in the xenograft, using transgenic livers expressing human decay accelerating factor on the endothelial surface results in prolonged graft survival and lower release of mediators.

Animals↗
PubMed1996

Reversal of blood flow direction for the salvage of forearm straight and looped ePTFE-shunts.

Long venous anastomotic stenosis of a forearm haemodialysis graft necessitates extension of the venous limb. If the extension graft crosses the antecubital region, it will be subject to kinking, and re-occlusion may be the consequence. We report our experiences with a procedure proposed by Schulak combining reversal of blood flow of forearm looped grafts and extension of the venous limbs along the ulnar aspect of the elbow. Detailed information is given on how to modify the original method in order to treat patients with straight grafts, or with looped grafts and a "misplaced" venous extension. Ten patients were successfully treated with Schulak's procedure or its modification. No intra- or post-operative complications occurred. During follow-up (from 3 to 12 months), all grafts have remained patent.

Anastomosis, Surgical↗
PubMed1996

Pulmonary arteriovenous malformations: aspects of surgical therapy.

Pulmonary arteriovenous malformations (PAVM) may occur primarily or in association with hereditary hemorrhagic telangiectasia (HHT, Rendu-Osler-Weber syndrome). Solitary or multiple fistulas may lead to clinical symptoms such as dyspnoe on exertion, central cyanosis, polycythemia, cerebral embolism, or brain abscess formation. Major neurological events may be first symptoms of PAVM. Between 1991 and 1995, 6 patients (age 25-69 years) underwent surgical treatment (2 segmental, 1 atypical, 3 anatomical resections) due to PAVM. The highest right-to left shunt fraction was 60% in a patient with a large posttraumatic fistula following war injury 50 years ago. Average shunt fraction was significantly reduced from 24 to 3% (p < 0.01), with no recurrance during follow-up. Aims of surgical resection in patients with PAVM are to reduce shunt fraction and to prevent neurological events following repeated cerebral embolism. Atypical or segmental resection is the operative method of choice; however, this is only recommended, if all contributing arteries are identified and selectively ligated. In case of central location of large fistulas, lobectomy may be necessary. Percutaneous selective embolization is an alternative treatment for patients with high operative risk or multiple fistulas. Its role for routine therapy remains to be determined by clinical studies.

Adult↗
PubMed1995

Treatment of lymphocele in renal transplant recipients by laparoscopic fenestration after transcutaneous staining.

Lymphocele is a rare cause of impairment of graft function after renal transplantation. Treatment ranges from external drainage to laparoscopic internal marsupialization. A therapeutic approach to the treatment of symptomatic lymphocele is described, which employs external drainage, if necessary followed by methylene blue staining and laparoscopic internal drainage, should conservative treatment fail. Five patients developed post-transplant lymphocele of varying size and were treated according to this protocol. Identification of the blue lymphocele at laparoscopy was straightforward and complete marsupialization was performed. After a mean follow-up of 8.4 months all patients are free from symptoms and have well functioning grafts.

Algorithms↗
PubMed1994

The beneficial effect of human recombinant superoxide dismutase on acute and chronic rejection events in recipients of cadaveric renal transplants.

In a prospective randomized double-blind placebo-controlled trial, the effect of rh-SOD, given in a dose of 200 mg intravenously during surgery to cyclosporine-treated recipients of cadaveric renal allografts, on both acute and chronic rejection events as well as patient and graft survival was investigated by analyzing the patients' charts retrospectively. The results obtained show that rh-SOD exerts a beneficial effect on acute rejection events as indicated by a significant reduction of (1) first acute rejection episodes from 33.3% in controls to 18.5%, as well as (2) early irreversible acute rejection from 12.5% in controls to 3.7%. With regard to long-term results, there was a significant improvement of the actual 4-year graft survival rate in rh-SOD-treated patients to 74% (with a projected half-life of 15 years) compared with 52% in controls (with an extrapolated half-life of 5 years). The beneficial effect of rh-SOD observed in this trial is not fully understood, although one can assume that the effect is related to its antioxidant action on ischemia/reperfusion injury of the renal allograft, thereby potentially reducing the immunogenicity of the graft. In addition and in accordance with the "response-to-injury hypothesis" in the pathogenesis of general atherosclerosis, rh-SOD has the potential to mitigate free radical-mediated reperfusion injury-induced acute endothelial cell damage that potentially may contribute to the process of chronic obliterative rejection arteriosclerosis.

Acute Disease↗