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Biomedical subjects

M Stangl

Publications and source records attributed to M Stangl.

At least 19 recordsLinked to original sources
PubMed2004

Periarterial application of papaverine during laparoscopic donor nephrectomy improves early graft function after kidney transplantation in pigs.

BACKGROUND: Laparoscopic donor nephrectomy (LDN) increases incentives to donation by subjects who might refuse an open operation. However, the incidence of delayed graft function is higher after LDN than after open operation. This may be caused by the reduction of renal perfusion as a result of the raised intraabdominal pressure and mechanically induced renal angiospasm during the operation. We conducted experiments to find out whether the application of papaverine around the renal artery during LDN could improve early graft function after transplantation. METHODS: Renal function was studied in 10 male pigs (weight approximately 25 kg). The left kidney was harvested laparoscopically (intraabdominal pressure 8 mmHg). Five animals were randomly selected to have perivascular application of 50 mg papaverine (treatment group) before preparation of the vessels. In controls no papaverine was used. After LDN and open right nephrectomy the left kidney was autotransplanted. The main outcome measures were volume of urine produced and creatinine clearance during the first 20 h after the transplant. RESULTS: The groups were comparable in respect of body weight, hemodynamic values, amount of infusions, warm and cold ischemia time, and duration of anastomosis. Urine output and creatinine clearance were significantly higher in pigs treated with papaverine than in controls. CONCLUSIONS: Papaverine substantially improved early graft function in pigs when applied around the renal artery during LDN. Whether this is applicable to procurement of human kidneys remains to be evaluated.

Animals↗
PubMed2003

The influence of periarterial papaverine application on intraoperative renal function and blood flow during laparoscopic donor nephrectomy in a pig model.

BACKGROUND: The transplantation of live donor kidneys harvested laparoscopically is associated with a higher incidence of delayed graft function than the transplantation of grafts harvested via the open technique. The delay is believed to be due to a decrease in renal blood flow during laparoscopic donor nephrectomy (LDN). The aim of this study was to evaluate whether renal function and blood perfusion can be enhanced by the periarterial application of papaverine during LDN. METHODS: Renal function and blood flow were studied in a porcine model that included a total of 24 pigs (20-30 kg). In 12 of the pigs, urine output and creatinine clearance were determined as measures of renal function. In the other 12 pigs, renal blood flow was determined using fluorescent-labeled microspheres. In each group, the pigs were randomized into two subgroups, one with and one without a perivascular injection of 50 mg papaverine. RESULTS: As compared to the controls, the animals receiving papaverine had a significantly higher urine output (3.1 +/- 1.6 vs 0.9 +/- 0.45 ml/h/kg; p = 0.02), superior creatinine clearance (2.22 +/- 0.5 vs 0.95 +/- 0.1 ml/min/kg; p = 0.038), and enhanced renal blood flow (4.9 +/- 2.2 vs 2.1 +/- 0.8 ml/min/g; p = 0.008). CONCLUSIONS: When applied to the tissue surrounding the renal artery, papaverine substantially improves renal function and blood flow during laparoscopic live kidney donation. Whether graft optimization during kidney procurement also translates into improved posttransplantation function remains to be established.

Animals↗
PubMed2003

[Kidney transplantation in Germany - 2002].

In Germany the number of kidney transplantations has increased rather slowly during recent years. While living donations increased, the number of postmortal donations decreased during the same time. In order to lower the number of patients on the waiting lists in Germany, the rate of postmortal or living donations as well as the number of marginal donors must be increased. Furthermore, risk factors related to the development of coronary heart disease or chronic allograft nephropathy, have to be strictly controlled in order to improve graft survival and, thus, reduce the waiting lists. In addition to the well established risk factors for graft survival such as HLA-missmatch, ischemia, coronary artery disease, metabolic diseases, or recipient/donor age others such as recipient/donor gender, social status, and patient education also influence graft survival. Screening for malignant tumors is crucial as donor and recipient age is increasing. Whether newer immunosuppressive substances such as mycophenolat mofetil (MMF), sirolimus, Il-2 receptor antagonists, or FTY720 prolong long term graft survival, has to be investigated in future clinical trials.

Adolescent↗
PubMed2001

Contrast-enhanced MR angiography in patients after kidney transplantation.

The aim of this study was to investigate the value of a contrast-enhanced 3D MR angiography in detecting postoperative vascular complications after kidney transplantation in comparison with digital subtraction angiography (DSA). Forty-one patients who underwent a kidney transplantation were examined with MR angiography and DSA. Contrast-enhanced MR angiography was performed as a dynamic measurement with one precontrast and three postcontrast measurements. Maximum intensity projection reconstructions were performed for all postcontrast data sets after DSA. The results were evaluated by two independent observers who were unaware of the DSA results. Twenty-three hemodynamically significant arterial stenoses were identified with DSA in the iliac arteries ( n=7), the renal allograft arteries ( n=12), and in their first branches ( n=4). For a patient-based analysis the sensitivity and specificity, respectively, for observer 1 were 100 and 97%, and for observer 2, 100 and 93%. Respective data were 100 and 100% after a consensus evaluation by two observers. Complications involving the renal veins were detected in 2 cases and perfusion defects of the kidney parenchyma were detected in 4 cases. Contrast-enhanced MR angiography is a reliable method in identifying postoperative arterial stenoses after kidney transplantation. In addition, dynamic MR angiography can be helpful in detecting venous complications and perfusion defects in kidney allografts.

Adult↗
PubMed2001

[Living donors in kidney transplantation. Renaissance by non-related donors?].

Renal Transplantation is hampered worldwide by the continuing lack of cadaveric organs. The discrepancy between the number of patients on the waiting list and the number of organs available is further compounded by the still unresolved problem of chronic transplant failure. Against this background, the arguments for increasing acceptance of the use of kidneys from living donors, both related and unrelated, are discussed. Initial reports on appreciably improved transplant survival rates of organs from unrelated living donors (85% survival after 3 years [19]) have since been confirmed by more recent studies. Our own results, in part obtained during a prospective study involving 103 patients (53 related, 50 unrelated) done between October 1994 and April 1999, with strict psychological care/evaluation prior to and after transplantation, revealed a four-year transplant survival rate of 98% in both groups. So far, the higher rejection rate of 34% in unrelated, vs. 13.2% in related, donors has not led to any earlier chronic dysfunction of the transplant. The expanded use of living kidney donors is not only ethically justifiable, but also improves the outcome.

Ethics, Medical↗
PubMed2001

Chronic persistent knee pain after repeated diagnostic arthroscopy: osteoid osteoma, a primarily overlooked diagnosis in a young woman.

We report a case of osteoid osteoma of the distal femur in an adolescent female patient that was primarily overlooked and led to repeated diagnostic arthroscopy of the knee. A thorough history and physical examination of the joint as well as adequate roentgenographic studies could have spared this patient two unnecessary arthroscopies and indicated the correct therapy.

Adolescent↗
PubMed2001

Standard heparin, low molecular weight heparin, low molecular weight heparinoid, and recombinant hirudin differ in their ability to inhibit transduction by recombinant adeno-associated virus type 2 vectors.

Recombinant adeno-associated virus type 2 (rAAV) is a promising vector for in vivo gene therapy. Transduction by rAAV requires binding to heparan sulfate proteoglycan on the cell surface, and heparin can block this binding. Because heparin is administered to most patients undergoing cardiovascular gene transfer in order to prevent thrombotic events, it is important to identify anticoagulants which do not interfere with rAAV transduction. Therefore, we examined the influence of different anticoagulants on rAAV transduction in vitro. rAAV transduction was inhibited by 40.5 +/- 7.9% at heparin concentrations of 0.1 U/ml, and by 81.7 +/- 3.6% at 1.0 U/ml. The low molecular weight (LMW) heparin tinzaparin inhibited rAAV transduction by 20.2 +/- 3.8% at 0.1 U/ml and 37.1 +/- 1.8% at 1.0 U/ml. The inhibitory effect was significantly weaker compared with heparin at 1.0 U/ml, (P < 0.01). The LMW heparinoid danaparoid inhibited rAAV transduction by 8.8 +/- 3.5% at 0.1 U/ml (P < 0.01 compared with heparin). In contrast, recombinant hirudin did not interfere at all with rAAV transduction. In summary, the results demonstrate that inhibition of rAAV transduction by heparin occurs rapidly and at therapeutically used concentrations. LMW heparinoids and above all recombinant hirudin might be alternatives for heparin when vascular gene transfer with rAAV requires transient anticoagulation.

Anticoagulants↗
PubMed1999

Repeated endoscopic ovum pick-up in sheep.

Endoscopy is an effective and minimally invasive technique which offers the possibility of repeated ovum pick-up (OPU). In this study 4 different treatment programs (Groups A, B, C and D) for repeated endoscopic OPU in sheep were investigated. The number of follicles and oocytes, quality of cumulus-oocyte-complexes (COCs), and detectable effects on fertility of the donor ewes were compared. Each group consisted of 5 East Friesian Milksheep. In Group A, follicles were punctured twice a week, in Group B once a week, and in Group C once a week followed by administration of 1500 IU PMSG 48 h prior to OPU. In Group D follicles were punctured and the sheep stimulated with 1500 IU PMSG 48 h prior to OPU once every 2 weeks. The PMSG-stimulated sheep received anti-PMSG immediately after OPU. Over a period of 10 weeks 216 OPU-sessions were performed. A total of 1978 follicles was punctured, and 1098 oocytes were recovered, for a collection rate of 55.5%. In the Groups A, B, C and D an average of 6.8, 8.6, 12.2 and 14.9 follicles per animal and session was aspirated, and an average of 3.8, 4.9, 7.0 and 7.6 COCs per animal per session was recovered, respectively. No significant differences between groups were observed in the collection rates (51.1 to 57.1%) or in the quality of the COCs, and 65 to 70% of the COCs were suitable for in vitro production of ovine embryos. Seven sheep developed small adhesions between the ovary and infundibulum. After the study 15 ewes became pregnant following natural mating with the same fertile ram (5 from Group A, 1 from Group B, 4 from Group C and 5 from Group D). In conclusion, OPU once a week in PMSG/anti-PMSG treated ewes was found to be the most effective treatment program for oocyte collection.

Animals↗
PubMed1999

Impact of immunoadsorption on xenogeneic extracorporeal pig liver perfusion: assessment of organ function during autologous reperfusion.

The shortage of liver grafts has resulted in an intensive search for alternative strategies of liver support in acute liver failure. Extracorporeal perfusion of pig livers (ECLP) is not a new concept, but recent improvements in cardiopulmonary bypass technology and new knowledge about xenogeneic immunologic mechanisms have made it a potential therapeutic modality. In previous suboptimal experimental and clinical models, no statements about the beneficial effect of long-lasting periods of ECLP were made. The aim of this study was to evaluate the capacity of pig liver for metabolic regeneration after xenogeneic ECLP under largely physiologic conditions. To delay hyperacute rejection (HAR), we utilized immunoadsorption (IA) of naturally preformed xenogeneic antibodies (XNAbs). This led to a stable xenogeneic ECLP for 45 min. However, IA was not able to prevent completely organ damage or loss of function resulting from insufficient autologous reperfusion. The inability to regenerate during autologous reperfusion provides a new measure of the function of a xenogeneic perfused pig liver. In addition, our results implicate that patients with fulminant liver failure will benefit from short perfusions with several fresh organs rather than from long perfusion with a single pig liver.

Animals↗
PubMed1999

Procalcitonin, a new indicator for non-viral infections in heart, lung or liver transplant patients.

PCT is a highly specific analyse which shows significant diagnostic validities when non-viral infections are compared with rejection episodes. PCT discriminates inflammatory events such as rejection or viral infections and non-viral infections including bacterial, fungal and protozoal infections. The half-life of PCT is 24 h indicating a clearly competent antibiotic treatment. PCT provides vital information early to clinicians and allows them to improve the management of bacterial/fungal infection in immunocompromised transplant patients. PCT thus facilitates and improves the outcome of survival rate and the quality of life in the postoperative period of patients with heart, lung or liver grafts.

Bacterial Infections↗
PubMed1998

Lectin-mediated bioadhesion: binding characteristics of plant lectins on the enterocyte-like cell lines Caco-2, HT-29 and HCT-8.

In order to take advantage of the biorecognition between lectins and specific carbohydrates for targeted drug delivery, fluorescein-labelled lectins of different carbohydrate specificities were screened for binding to human colorectal carcinoma cell lines by flow cytometry and confocal microscopy. The lectin-binding rate increased as follows: Dolichos biflorus agglutinin, DBA<peanut agglutinin, PNA<Lens culinaris agglutinin, LCA<Solanum tuberosum lectin, STL<Ulex europaeus isoagglutinin I, UEA-I<wheat germ agglutinin, WGA (Caco-2); PNA<UEA-I<WGA (HT-29); DBA<UEA-I<WGA (HCT-8), thus reflecting the glycosylation pattern of the cells. Compared to the BSA-binding capacity of the cells, the extent of nonspecific binding was strongly dependent on the type of cell line and lectin under investigation being lower than 2% in the case of WGA, STL and UEA-I/Caco-2 and HT-29 cells. Whereas 50% of DBA was bound nonspecifically to Caco-2 cells, the interactions DBA/HCT-8 and PNA/HT-29 were due to nonspecific binding. By competitive inhibition of lectin-adhesion to the cells upon addition of the complementary carbohydrate, specificity of lectin-binding was confirmed except for the interaction of DBA/HCT-8 and PNA/HT-29. Following on from this work, we consider WGA-, STL- and UEA-I-mediated drug delivery to be a promising approach for peroral bioadhesive formulations adhering to absorptive enterocytes.

Caco-2 Cells↗
PubMed1998

Mycophenolate mofetil-based, cyclosporine-free induction and maintenance immunosuppression: first-3-months analysis of efficacy and safety in two cohorts of renal allograft recipients.

BACKGROUND: The currently used macrolide immunosuppressants, i.e., cyclosporine and tacrolimus, exert considerable nephrotoxicity. We aimed to avoid the nephrotoxic effects by applying a cyclosporine-free regimen for the induction as well as for the maintenance treatment of renal allograft recipients using mycophenolate mofetil (MMF) as the primary immunosuppressant. METHODS: Thirteen patients were converted from cyclosporine (CsA) to MMF monotherapy. For 4 weeks, MMF (2 g/day) was added to the CsA treatment, before CsA was tapered by weekly steps of 25 mg/day and without "safeguard treatment" with additional immunosuppressants. In a second approach, 12 patients older than 50 years, and receiving a renal graft from a donor older than 50 years, were treated primarily with MMF combined with steroids and an induction therapy using antithymocyte globulin, and without the addition of CsA. RESULTS: Thirteen long-term renal transplant patients could be converted from CsA to MMF monotherapy. Conversion resulted in an immediate and long-lasting improvement of their median creatinine values by 20%. No serious adverse events occurred. In the second cohort of 12 patients, MMF was used as the primary immunosuppressant. All patients are alive and no grafts were lost after 4 months (n= 12) and after 6 months (n=7). The median creatinine values achieved after 4 and 6 months were 1.16+/-0.25 and 1.30+/-0.21 mg/dl, respectively. One patient was converted to CsA because of a reversible rejection episode (8.3%), and another patient was converted because of cytomegalovirus disease. Major complications consisted of wound-healing disturbances (16.6%) and cytomegalovirus infections (41.6%). CONCLUSION: MMF monotherapy can be safely applied as long-term maintenance immunosuppression with improvement of renal function. Steroids are not required as an adjunct to MMF. MMF monotherapy, in the absence of drug-related nephrotoxicity, is particularly beneficial for grafts derived from marginal donors, such as donors of advanced age.

Acute Disease↗