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Biomedical subjects

R Margreiter

Publications and source records attributed to R Margreiter.

At least 19 recordsLinked to original sources

[Model of electromyographic study of small intestinal transplants in the rat].

Adequate motility of a small bowel transplant is a prerequisite for its resorptive function as well as its self-purging capacity. The literature contains some reports on changes in motility following denervation or transplantation, but none on the impact of acute rejection on motility of small bowel grafts. Therefore an experimental model was established to meet the following criteria: orthotopic position of graft, adequate nutritional status even when graft is functionally impaired, chronically implantable electrodes attached to graft and corresponding segment of native bowel, isogeneic or allogeneic set-up. 10 cm of proximal jejunum were transplanted from Lewis donors to five Lewis recipients in an orthotopic position just distal of the ligament of Treitz without resection of native small bowel. Three bipolar electrodes were sutured to the graft and the same number to the subsequent recipient bowel. Serial myoelectric measurements were taken until the end of week 3. From day 5 on, migratory myoelectric complexes independent of myoelectric activities of native bowel were recorded. Pacemaker frequency of the graft was found to be the same as that of the transsected native small bowel. This early reappearance of myoelectric activities makes this model suitable for comparative studies of small bowel transplant motility and in particular its changes during rejection, since even in strongly allogeneic combinations Lewis small bowel does not show histological signs of rejection before day 6.

Animals

Hepatocellular transplantation into the lung for temporary support of acute liver failure in the rat.

Because hepatocyte transplantation into the spleen or the peritoneal cavity, although successful in rats, is more difficult and less successful in larger animals, the lung was chosen for its accessibility and its high oxygen content as a new site for hepatocyte implantation for treatment of acute hepatic failure. Acute hepatic failure was induced by a combination by a portocaval side-to-side shunt and an 80% liver resection, which was associated with a greater than 90% mortality. Hepatocyte transplantation was performed either by injection of 1 x 10(7) cells via the jugular vein (100% mortality) or 5-7 x 10(7) cells transcutaneously into the right lung (92% survival). After injection of the cell-free supernatant into the lung, 53.3% of the animals survived. If more than 90% of the liver was resected, none of the animals survived despite hepatocyte or supernatant injection. From these findings, it is concluded that the lung is a suitable home for hepatocytes. However, the hepatocytes survived only in cases of acute hepatic failure with some remaining vital liver parenchyma.

Acute Disease

Relationship between quantity of silver stained nucleolar organizer regions associated proteins (Ag-NORs) and population doubling time in ten breast cancer cell lines.

Using a one-step silver staining technique ten human breast cancer cell lines were investigated, determining by means of automated image analysis the mean area of Ag-NORs per nucleus, the total number of Ag-NORs, and the so-called "scattered" and "clustered" Ag-NORs. These parameters were statistically correlated with the population doubling time (PDT) of the various carcinoma cell lines of this series. Our results show that the mean area of Ag-NORs per nucleus (p less than 0.001) is highly significantly correlated to the PDT, whereas all other parameters were less or not significant. It is concluded that the assessment of the area of Ag-NORs by automated image analysis is a simple and reliable method for the determination of cell duplication rates.

Breast Neoplasms

Interleukin-8 serum concentrations after liver transplantation.

The study's objective was to investigate serum levels of interleukin-8 (IL-8) after liver transplantation and to correlate these findings with tumor necrosis factor alpha serum levels and various clinical parameters. This was a prospective observation study conducted at the University Hospital of Innsbruck with 19 patients studied after orthotopic liver transplantation. Serum levels of IL-8 were analyzed by a solid-phase double ligand ELISA method. Serum TNF-alpha concentrations were measured by means of a commercially available radio immunoassay (IRE-Medgenix, Fleurus, Belgium). Three patients with an uneventful recovery after transplantation showed IL-8 levels below the detection limit. IL-8 serum levels markedly increased in patients with acute graft rejection, bacterial infection, and CMV disease. Increments of serum IL-8 preceded clinical complications in all patients. Highest levels were observed in bacterial infection, lowest in acute rejection. A statistically significant positive correlation was demonstrated between IL-8 and TNF-alpha serum levels in the context of bacterial infection and CMV disease. Elevated IL-8 serum levels represent a feature of alloimmune and infectious complications following liver transplantation. IL-8 can thus be considered a further indicator molecule in the heterogenous group of acute-phase reactants that accompany various inflammatory responses and do not permit the underlying clinical complication to be specified.

Adult

Urinary and pancreatic juice neopterin excretion after combined pancreas-kidney transplantation.

The aim of this study was to investigate excretion of urinary and pancreatic juice neopterin in patients after combined pancreas-kidney transplantation and to relate it to the clinical course. The study design was a prospective observation study. Thirty consecutive patients with end-stage diabetic disease received a simultaneous pancreas-kidney transplant with pancreaticocystostomy and temporary exteriorization of pancreatic juice. In 30 patients urinary neopterin (UN) was measured daily from day +1 until hospital discharge by high-performance liquid chromatography; in ten of these 30 patients pancreatic juice neopterin (PJN) was additionally analyzed daily from day +1 for as long as pancreatic juice was diverted to the exterior. Elevated urinary neopterin levels were observed in acute cellular rejection (19/24 rejection episodes) and in bacterial infection (9/16 cases)--however, increments were more pronounced in acute cellular rejection. In contrast, pancreatic juice neopterin increased in all seven observed pancreatic graft rejection episodes. Pancreatic juice infection did not result in a rise in pancreatic juice neopterin excretion. Patients without postoperative complications exhibited stable and low urinary/pancreatic juice neopterin levels. The highest urinary neopterin levels were observed in CMV disease. Levels measured prior to discharge from hospital did not correlate with graft and patient survival. Evaluation of urinary and pancreatic juice neopterin, although nonspecific, helps identify patients with an uncomplicated or complicated clinical course. Pancreatic juice neopterin appears to be superior to urinary neopterin in early detection of pancreatic graft rejection. This may be of particular importance in monitoring nonuremic pancreas allograft recipients.

Adult

Circulating serum levels of interleukin 6 and C-reactive protein after liver transplantation.

The study objectives were to investigate serum levels of interleukin-6 and C-reactive protein (CRP) after liver transplantation to correlated measurements with various clinical parameters. Twenty-three patients were studied after orthotopic liver transplantation. Serum IL-6 activity was evaluated by testing its capacity to induce proliferation of the IL-6-dependent hybridoma cell line B9. CRP was assessed by a nephelometric method. Only two of seven patients with acute cellular rejection developed an increase of serum IL-6 and CRP. In contrast to this rejection group, elevated IL-6 levels were observed in 7/9 patients with bacterial infections. Peak values for IL-6 were observed one day and for CRP two days after clinical diagnosis of infection. CMV disease was also associated with markedly increased IL-6 and CRP levels in 5/7 patients. Surprisingly, levels in this condition were approximately in the same range as in bacterial infection. IL-6 and CRP serum levels seen in bacterial infection and CMV disease were significantly higher than those in rejection (P less than 0.001). Serum IL-6 activity was neutralized by an antiserum directed against recombinant human IL-6. Preferential elevations of IL-6 and CRP represent one feature of bacterial and viral infections. Elevation of TNF during rejection as described earlier is only rarely accompanied by increased serum IL-6 levels.

Bacterial Infections

[Development and importance of combined organ transplantation].

In 1966, Kelly and Lillehei transplanted a pancreas together with a kidney in a young patient suffering from end-stage diabetic nephropathy. Since this first combined organ transplantation, various organs have been transplanted together: heart-lung (Cooley 1969), liver-kidney (Margreiter 1983), liver-pancreas-stomach-small bowel (Starzl 1983), heart-liver (Starzl, Bahnson 1984), heart-lung-liver (Wallwork, Calne 1986), and liver-small bowel (Grant 1990). Although some of these combined organ transplants will only occasionally be necessary, some others such as kidney-pancreas, heart-lung, or liver-kidney have already gained clinical relevance.

Humans

[Personal experience with prevention and therapy of infection after 53 liver transplantations].

An attempt was made to reduce the risk of infection following liver transplantation by means of selective bowel decontamination with tobramycin, polymyxin E and amphotericin B, as well as short-term systemic antibiotics with cephotaxim and tobramycin. After 53 consecutive orthotopic hepatic transplants performed in 51 patients between 1985 and 1987, a total of eight pneumonias occurred as the clinically most significant infection. Two pneumonias were caused by cytomegalovirus, one by Pneumocystis carinii, one by Candida and the remaining four by various bacteria. In 6 patients, bacteria were cultured from the blood, but only in one case was an indwelling catheter identified as the source of the septicemia. Taking all samples together, Streptococcus faecalis was the bacterium most frequently cultured, which was not covered by the prophylactic antimicrobial regime applied. Pseudomonas, however, and gram-negative bacteria were demonstrated much less frequently. Vaginal and oral Candida infections, as well as oral and genital herpes simplex infections, responded well to topical therapy with fungicide and aciclovir, respectively. Three patients developed cytomegalovirus (CMV) hepatitis. All five CMV infections were successfully treated with ganciclovir and hyperimmunoglobulin, as well as reduction of prophylactic immunosuppression. Out of 15 patients transplanted for posthepatitic cirrhosis, 7 developed a recurrence of the infection (5 hepatitis B virus) 2 hepatitis C virus) in the graft. Two died of the cirrhosis, three are still alive with cirrhosis but sufficient graft function, and one patient is suffering from chronic active hepatitis. One patient grafted for acute hepatic failure was able to clear the delta virus within 1 year post-transplant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent