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Biomedical subjects

W O Bechstein

Publications and source records attributed to W O Bechstein.

At least 145 records · Page 8Linked to original sources
PubMed1997

Treatment of cyclosporine-related adverse effects by conversion to tacrolimus after liver transplantation.

BACKGROUND: Cyclosporine (CsA)-associated side effects include nephrotoxicity, hypertension, neurological disorders, and hyperlipidemia. A considerable share of early and long-term posttransplant morbidity is likely to be drug related. METHODS: In 31 patients with stable graft function, conversion from CsA to tacrolimus was implemented due to nephrotoxicity (n=19), hypertension (n=9), and neurological disorders (n=8). RESULTS: Three months after conversion, a response was evident in 26 patients (84%), whereas 5 patients (16%) were nonresponsive. In 13 of 19 patients (68%) suffering from nephrotoxicity, serum creatinine levels decreased significantly from 2.0+/-0.5 mg/dl to 1.5+/-0.4 mg/dl (P<0.005), whereas in 6 of 19 patients (32%) no improvement was observed. Antihypertensive therapy was reduced in six of nine patients and neurological disorders improved in six of eight patients. When analyzing all patients, average levels of cholesterol and triglycerides were significantly lower after conversion when compared with at the time of conversion (P<0.05) CONCLUSIONS: Conversion to tacrolimus reduced drug-related side effects in the majority of patients, while graft function remained stable. Conversion to tacrolimus may be considered for CsA-related side effects as a potential beneficial approach.

Adult↗
PubMed1997

De novo malignancies after liver transplantation using tacrolimus-based protocols or cyclosporine-based quadruple immunosuppression with an interleukin-2 receptor antibody or antithymocyte globulin.

BACKGROUND: Although conventional immunosuppression after liver transplantation consists of cyclosporine A (CsA), steroids, and azathioprine, recently introduced protocols entail CsA-based quadruple induction protocols or tacrolimus-based combinations. These protocols aim to reduce the rejection rate and the considerable morbidity related to the side effects of additional immunosuppressive treatment, but have not yet been analyzed regarding their long term de novo neoplastic risk. METHODS: From September 1988 to May 1994, 500 liver transplantations were performed in 458 patients. The median follow-up was 50 months (range, 0.3-97 months) for all patients. Conventional triple therapy was implemented in 25 patients, CsA-based quadruple induction therapy using an antilymphocyte globulin preparation (ATG) in 190 patients, an interleukin-2 receptor antibody (BT563) in 141 patients, and tacrolimus-based dual or triple immunosuppression in 102 patients. The different protocols were evaluated in four randomized and two nonrandomized prospective trials. RESULTS: De novo neoplasias were detected in 33 patients (7.2%) and were comprised of lymphomas (n = 7), skin malignancies (n = 8 lesions in 7 patients), intraepithelial neoplasias of the cervix uteri (n = 7), breast carcinoma (n = 3), lung carcinoma (n = 3), and other malignancies (n = 6). The incidence of de novo neoplasias did not differ in the different trial arms. Only a positive T-crossmatch and a low CD4+/CD8+ ratio in patients receiving CsA-based immunosuppression demonstrated a significant correlation with the development of a de novo tumor in a multivariant logistic regression analysis. CONCLUSIONS: The development of de novo neoplastic diseases after liver transplantation with the use of CsA-based quadruple induction protocols or tacrolimus-based regimens for immunosuppresion was assessed over the long term. Recently introduced immunosuppressive protocols did not alter the posttransplant de novo tumor rate. Patients with a low CD4+/CD8+ ratio during CsA-based therapy or a positive T-crossmatch were identified to be at an increased risk for the development of a de novo malignancy.

Antibodies, Monoclonal↗
PubMed1997

Chronically rejected rat kidney allografts induce donor-specific tolerance.

Previous studies on pathophysiological mechanisms of chronic graft rejection demonstrated the impact of both alloresponsiveness and nonspecific immunological events on the process. To study the role of alloantigen-specific factors further, we hypothesized an acceleration of chronic graft rejection after presensitization. Chronically rejected renal allografts in the established Fischer 344 --> Lewis rat model were replaced sequentially by native allografts of donor origin. Grafting of second allografts was performed 2, 4, 8, and 12 weeks after the original transplantation and followed long term. Second allografts demonstrated significantly ameliorated functional and structural alterations with few cellular infiltrates. These changes were independent from the time interval between first and second engraftment (2-12 weeks); immunosuppressive treatment after the second engraftment was not influential. The nonresponsiveness was not restricted to the second kidney allografts, as heart allografts of donor origin in these recipients also functioned indefinitely, whereas third-party grafts (Lewis x Brown Norway F1) and Fischer 344 heart grafts in untreated Lewis control rats were acutely rejected. Thus, donor-specific and tissue-nonspecific graft acceptance is achieved by second engraftment of donor-specific allografts in a model of chronic graft rejection. Those observations demonstrate the synergistic effects of alloresponsiveness and of the injured graft itself for the development of chronic graft failure.

Animals↗
PubMed1997

A prospective randomized trial comparing interleukin-2 receptor antibody versus antithymocyte globulin as part of a quadruple immunosuppressive induction therapy following orthotopic liver transplantation.

BACKGROUND: Quadruple immunosuppressive induction therapy has been shown to markedly reduce the incidence of acute rejection episodes without increasing the incidence of infectious complications after liver transplantation. However, the use of polyclonal antibody preparations (e.g. antithymocyte globulin [ATG]) is associated with side effects such as fever and tachycardia. To evaluate the efficacy and the safety of a monoclonal antibody directed against the interleukin-2 receptor (BT563) in comparison with ATG as part of a quadruple induction regimen, a prospective, randomized study was conducted. METHODS: Eighty consecutive adult recipients of primary orthotopic liver transplants were randomized to receive either BT563 (10 mg/day; days 0-12; n=39) or ATG (5 mg/kg/day; days 0-6; n=41) in addition to the standard immunosuppressive protocol consisting of cyclosporine, and prednisolone, and azathioprine. RESULTS: Patients treated with BT563 had a significantly lower incidence of steroid-sensitive rejection episodes (3 vs. 11; P<0.025) and also significantly fewer drug-related side effects (4 vs. 18, P<0.038) when compared with patients treated with ATG. The incidence of infectious complications was not different between the two groups. Patient survival did not differ significantly between the two groups (84.6% at 1, 2, and 3 years in the BT563 group and 90.2% at 1 year and 87.8% at 2 and 3 years for the ATG group). Analysis of graft function showed an advantage for the BT563 group in terms of postoperative bilirubin levels. However, no differences were observed in long-term follow-up between the two groups. CONCLUSIONS: Our results indicate that treatment with anti-interleukin-2 receptor antibody as part of quadruple induction therapy after orthotopic liver transplantation is safe and effective and shows fewer steroid-sensitive rejection episodes as well as fewer side effects when compared with quadruple induction therapy including ATG.

Adult↗
PubMed1997

A pretransplant infection with precore mutants of hepatitis B virus does not influence the outcome of orthotopic liver transplantation in patients on high dose anti-hepatitis B virus surface antigen immunoprophylaxis.

Hepatitis B virus (HBV) infection of the liver graft is a major complication after orthotopic liver transplantation (OLT) for HBV-related cirrhosis. A high viral load before OLT is a known risk factor, whereas the relevance of precore mutants of HBV is a subject of controversy. The aim of this study was to correlate the pretransplantation viral load and a pretransplantation infection with precore mutant HBV (pmHBV) or wildtype HBV (wtHBV) with allograft damage, graft failure, and survival after OLT. Sixty-nine patients with HBV cirrhosis underwent OLT under high dose immunoprophylaxis with anti-hepatitis B surface (HBs) hyperimmunoglobulins (HBIg). A pretransplantation infection with pmHBV and wtHBV was detected by polymerase chain reaction (PCR) and direct sequencing in 30 patients each (pmHBV and wtHBV group). Nine of 69 patients were PCR-negative (noHBV group). Median pretransplantation levels of HBV DNA assessed by hybridization assay were 42 pg/mL for pmHBV and 54 pg/mL for wtHBV patients. HBV recurred in 17 of 30 (57%) of pmHBV and in 14 of 30 (47%) of wtHBV patients and graft failure occurred in 6 of 30 (20%) of pmHBV and 7 of 30 (23%) of wtHBV patients. Neither HBV recurrence nor graft failure occurred in patients in whom no HBV DNA could be detected by PCR using primers flanking the HBV precore region (noHBV) patients. Allograft damage assessed by histology activity index (HAI) scoring was median 6 for pmHBV and 7 for wtHBV patients. Cumulative survival after 5 years was 72% for pmHBV, 74% for wtHBV, and 100% for noHBV patients. In this study, we provide evidence that pretransplantation viral load, but not infection with pmHBV, determines the outcome after OLT in patients on high dose HBIg prophylaxis.

Adult↗
PubMed1997

Bile acid-independent bile flow is differently regulated by glucagon and secretin in humans after orthotopic liver transplantation.

The present study characterizes recovery of bile secretion after orthotopic liver transplantation (OLT) in humans with special regard to hormonal regulation of bile acid-independent bile flow by glucagon and secretin. Sixty-seven patients with an uncomplicated postoperative course were studied during the first 3 weeks after OLT to determine normalization of bile flow. A group of 7 and 10 patients, respectively, underwent a biliary stimulation test by either glucagon at days 7, 14, and 21 after OLT or by secretin at days 2, 10, and 21 after OLT. Secretin tests were similarly performed in patients with acute severe rejection during the first 10 days after OLT, while glucagon tests were performed in patients with acute allograft rejection occurring 2 weeks after OLT. Furthermore, hormone effects were studied in nontransplanted patients after cholecystectomy with indwelling biliary T tube. After OLT, bile secretory function recovered and stabilized within 14 days after surgery by reconstitution of both bile acid-dependent and -independent bile flow. Two weeks after OLT, bile secretion was comparable with nontransplanted patients after cholecystectomy. Glucagon and secretin stimulated bile acid-independent bile flow in transplanted and nontransplanted patients significantly, yet secretin choleresis, unlike glucagon choleresis, had already occurred during the first days after OLT and was unaffected by acute allograft rejection. These results allow the speculation that, in humans, glucagon and secretin exert their choleretic activity by different mechanisms and/or at different anatomical sites in the liver. Assuming that secretin acts at the bile duct cells, its secretory capacity was not altered by the transplantation procedure and during moderate or severe rejection episodes, as opposed to glucagon choleresis, which most likely originates in the hepatocytes and requires an entirely reconstituted canalicular transport system after OLT.

Acute Disease↗
PubMed1997

[Intra-abdominal schwannoma. Diagnosis and surgical therapy].

We report three patients who were operated on because of an intraabdominal schwannoma between February 1991 and October 1994 in our department. In the first case, a benign gastric schwannoma was treated by a distal gastric resection (Billroth II); the main symptom was gastric bleeding. In the second case, a malignant duodenal schwannoma with liver metastasis was treated by wide en-bloc resection of the tumor including retroperitoneal lymphadenectomy and an anatomical resection of the right lobe of the liver. A metachronous metastasis of the liver, appearing 7 months postoperatively, was treated by intraparenchymatous laser coagulation; a local recurrence, appearing 19 months postoperatively, led to another tumor resection. The main symptom was a palpable intraabdominal mass in this case. In the third case, a malignant schwannoma of the abdominal wall was resected in fragments in another clinic. Six months later a local recurrence with infiltration of the liver appeared in spite of postoperative radiation and was resected en bloc. Early peritoneal sarcomatosis was apparent at that time. Postoperative chemotherapy did not prevent quick progression of the tumor. The patient died 18 months after the first operation. The clinical presentation, differential diagnosis and operative strategy for benign and malignant intraabdominal schwannomas are discussed.

Abdominal Neoplasms↗
PubMed1997

Mycophenolate mofetil added to immunosuppression after liver transplantation--first results.

Mycophenolate mofetil (MMF) has been used successfully as an immunosuppressive agent after kidney and heart transplantation, but experience with MMF after liver transplantation is still limited. Between August 1995 and January 1996, we treated 20 patients with MMF after orthotopic liver transplantation in an open, prospective study. Five out of eight patients with acute rejection and one patient with early chronic rejection showed a complete response after MMF was added to the immunosuppression. Three patients with chronic rejection did not improve, one died, and two have stable graft function at present. In eight patients who suffered from toxicity, a reduction in the dosage of tacrolimus was attempted with simultaneous MMF therapy. One patient died due to multiple organ failure. Liver function improved completely in one other patient, and partially in three patients after adding MMF. In the remaining three patients, a reduced dosage of tacrolimus or cyclosporin, together with MMF, reduced toxicity, not significantly. In conclusion, MMF appears to be a safe and potentially useful adjuvant immunosuppressive agent for rescue and maintenance therapy.

Acute Disease↗
PubMed1997

p53 hot-spot mutational analysis in advanced Western gallbladder carcinoma.

In gallbladder carcinoma, studies on the prime target of genetic alterations and gene therapy in human gallbladder malignancies, the p53 tumor suppressor gene, have been focusing on this gene's immunohistochemical detection. From November 1991 to October 1993, seven patients suffering from gallbladder carcinoma underwent surgical resection. Cancerous and normal liver tissues were obtained immediately after surgery, snap-frozen in liquid nitrogen, and stored at -80 degrees C for immunohistochemistry and DNA isolation. Exons 5, 6, 7, and 8 of the p53 gene were completely sequenced following polymerase chain reaction (PCR) amplification of a 1574-bp fragment. Missense mutations were detected in the cancerous tissues of two patients: one transition each on codons 134 (Phe-->Leu) and 146 (Trp-->Arg). Immunohistochemical p53 staining was positive in the latter patient only. This is the first report on sequence analysis and mutagenesis of the p53 gene in Caucasian patients with gallbladder cancer. Both mutations were transitions and seem to represent a rather rare event. The possible impact of p53 mutagenesis on gallbladder tumorigenesis requires evaluation in larger studies.

Adenocarcinoma↗
PubMed1997

Heterogeneity of liver cells expressing procollagen types I and IV in vivo.

The extracellular matrix of fibrotic liver is predominantly produced by mesenchymal cells, the in vivo phenotype of which is poorly defined. We report on the application of combined immunohistology and in situ hybridization with [35S]-labeled alpha 1(I) and alpha 1(IV) procollagen RNA probes. In CCl4-treated rats, all alpha 1(I) procollagen-producing cells were vimentin positive but cytokeratin negative; over 90% expressed desmin, a marker of rat liver stellate cells. alpha 1(I) Procollagen-expressing, desmin-negative cells were confined to portal tract and perivascular stroma. Similarly, alpha 1(I) procollagen gene transcripts were, in all instances, colocalized with vimentin in human liver. In fibrotic specimens, over 70% of these cells expressed alpha-actin. Antibodies against epithelial, endothelial, and Kupffer cells, granulocytes, and lymphocytes did not react with alpha 1(I) procollagen RNA-expressing cells. Localization, morphology, and immunophenotype of alpha 1(I) procollagen-expressing cells indicated stellate cells and portal/vascular fibroblasts, but not epithelial cells, to be sources of hepatic interstitial collagen. However, most alpha 1(IV)-expressing human liver cells were identified as endothelial cells, the remaining cells were (myo-)fibroblastic and bile duct epithelial cells, but not hepatocytes. This indicates synthesis of procollagen type IV from both sides of the basement membrane and suggests an active participation of endothelial cells in the process of sinusoidal capillarization.

Adult↗
PubMed1997

Female sex hormone receptor status in advanced hepatocellular carcinoma and outcome after surgical resection.

BACKGROUND: There is a limited amount of data regarding the estrogen receptor (ER) and progesterone receptor (PgR) status of hepatocellular carcinomas (HGCs), and the relationship between receptor status and clinicopathologic features of tumors has not been reported. METHODS: Between April 1992 and December 1993, cancerous tissues for cytosolic preparation and receptor quantification in a monoclonal solid-phase enzyme immunoassay were obtained from 28 patients undergoing resection, three patients with total hepatectomy and subsequent liver transplantation, and two patients suffering from nonresectable HCC. RESULTS: ER and PgR were detected in the HCCs of 13 (39%) and 6 patients (18%), respectively. A lower age was observed among the female patients whose receptor status was negative for ER or PgR or both, as compared with the respective receptor-positive groups. No significant differences with respect to tumor stage and grading could be observed. There was one perioperative death (3%). In patients undergoing curative resection, 1-year survival in the ER(+) group was significantly lower than in the ER(-) group (40% versus 79%, p < 0.05). The 2-year survival rates in the ER(+) and ER(-) groups were 40% and 71%, respectively. A comparable trend did not become evident for PgR(+) and PgR(-) patients. CONCLUSIONS: Our data suggest a negative effect of an ER(+) tumor on patient survival after curative resection of advanced HCC.

Aged↗