W Niebel

University of Duisburg-Essen, Essen, North Rhine-Westphalia, Germany

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Publications (63)169.45 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Intraileal carbohydrates and lipids affect the pancreatic exocrine secretion, but the effect of intraileal amino acids and the role of the extrinsic nerves of the ileum as mediators of the pancreatic bicarbonate and enzyme output are unknown. Methods: Four dogs underwent total extrinsic denervation of the entire ileum. Thomas-like cannulas were placed into the stomach, duodenum (to collect pure pancreatic juice), and at the jejuno-ileal junction. Eight neurally intact control dogs received only the three fistulas. After recovery, in both sets of dogs, dose-response studies of the pancreatic secretory response to intraileal infusion with graded loads of tryptophan (0.12–10.0 mmol/h) were performed, given against an intravenous (iv) background of secretin (20.5 pmol/kg/h) and cerulein (29.6 pmol/kg/h). On separate days, control experiments with intraileal infusion of 0.15 M NaCl were performed. Results: In both sets of dogs, iv secretin plus cerulein significantly (p<0.05) increased pancreatic bicarbonate and protein output above basal. Intraileal tryptophan caused a dose-dependent decrease in the pancreatic bicarbonate and protein response to secretin plus cerulein. In the dogs with denervated ileum, this inhibition was significantly stronger than in the intact animals. In both sets of dogs, the 225-min integrated bicarbonate (IBR) and protein response (IPR) to all loads of tryptophan were significantly lower than in control experiments. Both IBR and IPR were significantly lower in the denervated as compared with the intact animals. Conclusions: 1) Extrinsic denervation of the entire ileum is a valuable preparation to study the role of nerves in the control of pancreatic exocrine secretion; 2) both in the intact and denervated animals the amino acid tryptophan induces an “ileal brake” of the hormonally stimulated pancreatic bicarbonate and protein output; 3) the extrinsic nerves of the ileum are probably not the dominant mediators of the inhibitory action of intraileal tryptophan but rather counteract this effect.
    International Journal of Gastrointestinal Cancer 04/2012; 28(2):83-90. DOI:10.1385/IJGC:28:2:083
  • J Friedrich, W Niebel, J Erhard
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    ABSTRACT: The pancreas-kidney transplantation strives for a reestablishment both of the physiological regulation of blood glucose levels without external insulin and of kidney function without the need of dialysis. Nevertheless, the postoperative morbidity of the combined transplantation is high. In long lasting diabetes type I, a strict selection of transplant candidates is necessary to minimize the risks of cardio-vascular complications. Between 1990 and 1997 only 17 of 44 patients really were accepted for transplantation in our unit. 13/17 patients are actually independent from external insulin and dialysis. Two other patients are free of dialysis, but the pancreas transplants had to be removed due to thrombosis or infection. In one case therapy-resistant acute rejection occurred and both organs had to be removed after two months. One women died four years after transplantation with a functioning kidney graft from myocardial infarction. 10 patients with stable transplant function are at work again. After normal pregnancy two women gave birth to healthy children, in one case twins. Drug regimen and outpatients visits are not seen as significant restrictions of the quality of life.
    Zentralblatt für Chirurgie 02/1999; 124(8):739-42; discussion 472. · 1.19 Impact Factor
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    ABSTRACT: In two sets of dogs with gastric, duodenal, and jejunal fistulas, we studied the effect of atropine (14 nmol/ kg/h) on the pancreatic secretory response to intrajejunal tryptophan (0.12-10.0 mmol/h; given against a secretin background) before (n = 7) and after extrinsic denervation of the jejunoileum (orthotopical autotransplantation; n = 6). Plasma levels of cholecystokinin were determined by radioimmunoassay. The incremental bicarbonate response to tryptophan was not significantly different between the two sets of dogs. Atropine had no effect on the incremental bicarbonate response to tryptophan. In both sets of dogs, intrajejunal tryptophan caused a dose-dependent increase in pancreatic protein output, which was reduced by atropine. The tryptophan-stimulated levels of plasma cholecystokinin were not significantly altered by denervation and or atropine. We conclude that in dogs (1) intrajejunal tryptophan stimulates pancreatic bicarbonate and protein secretion via release of hormones, (2) extrinsic denervation of the jejunoileum does not significantly alter the incremental bicarbonate and protein responses to intrajejunal tryptophan, (3) the cholinergic intrinsic nerves of the jejunoileum and the hormone cholecystokinin are probably involved in control of the pancreatic protein response to tryptophan, and (4) the release of cholecystokinin by intrajejunal tryptophan does not depend on the extrinsic and intrinsic cholinergic nerves of the jejunoileum.
    Pancreas 06/1997; 14(4):383-90. · 3.01 Impact Factor
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    ABSTRACT: The prognosis of patients with locally advanced esophageal cancer (LAEC) remains poor when treated with local modalities. An intensive preoperative program with chemoradiotherapy was used to evaluate the curative resection rate, pathologic response, and survival of patients with LAEC. Ninety patients with LAEC were treated preoperatively with chemotherapy (three courses of fluorouracil, leucovorin, etoposide, and cisplatin [FLEP]) followed by concurrent chemoradiotherapy (one course of cisplatin plus etoposide in combination with 40 Gy of radiation). Transthoracic esophagectomy was performed 4 weeks after the end of radiation. Seventy-two patients were included in this evaluation. Forty-four (61%) underwent a complete tumor resection, and 16 (22%) had no tumor in the resected specimen (pathologic complete response [PCR]). The operative mortality rate was 15%. At a median follow-up time of 22 months (range, 12 to 41), the median survival duration of all 72 patients was 17 months (range, 1 to 41+). The calculated survival rates at 3 years were 33%, 42%, and 68% for all patients, patients after complete resection, and patients with PCR, respectively. This combined treatment modality is active in LAEC, with a PCR in 33% of the patients undergoing surgery. The results appear improved compared with those reported with surgery alone, by approximately doubling the 3-year survival rate. The high efficacy of preoperative chemoradiation warrants evaluation of the role of surgery in LAEC.
    Journal of Clinical Oncology 04/1996; 14(3):829-37. · 17.88 Impact Factor
  • Gastroenterology 04/1995; 108(4):A395-A395. · 13.93 Impact Factor
  • Radiotherapy and Oncology 04/1994; 31. DOI:10.1016/0167-8140(94)91141-X · 4.86 Impact Factor
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    ABSTRACT: Three patients were treated suffering from a severe HELLP-syndrome. The problems as far as the diagnostic and therapy are concerned are discussed. All three patients had to be operated on in an emergency state. The operations were performed due to acute and severe abdominal bleeding. Two of the patients needed liver transplantation as an emergency procedure, one of them died after hepatectomy waiting for a graft. Another one died seven weeks after successful transplantation due to prolonged sepsis. The third patient is more than one year after transplantation alive and doing well.
    Zentralblatt für Chirurgie 02/1994; 119(5):298-304. · 1.19 Impact Factor
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    ABSTRACT: In a 5 years period 5 female patients suffering from a severe HELLP syndrome were treated. The problems concerning diagnostic and treatment are discussed. 3 patients had to be operated on in an emergency state. The operations were performed because of acute and severe abdominal bleeding. Two of the patients needed liver transplantation as an emergency procedure, one of them died after hepatectomy on the list. Another one died 7 weeks after successful transplantation in a state of prolonged sepsis. The two conservatively treated and the one transplanted patient are still alive and well.
    Zeitschrift für Gastroenterologie 02/1994; 32(1):16-20. · 1.67 Impact Factor
  • Update in Gastric surgery, Edited by Röher H.-D, Heise J.W., Vereet P.R., Varney M., 01/1994: chapter Intraoperative radiotherapy for gastric cancer: pages 133-137; Georg Thieme Verlag Stuttgart New York.
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    ABSTRACT: We discuss the case of a 30-year-old primipara woman who developed a liver rupture as a complication of the HELLP syndrome. A liver necrosis and bleeding made a hepatectomy necessary. A portocaval shunt was able to maintain the patient until she underwent urgent liver transplantation. In an excellent state of recovery, the woman and her baby were discharged from the hospital 66 days after having been admitted.
    Transplant International 06/1993; 6(3):179-81. DOI:10.1111/j.1432-2277.1993.tb00643.x · 3.16 Impact Factor
  • Transplantation Proceedings 01/1993; 24(6):2748-9. · 0.95 Impact Factor
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    ABSTRACT: Thirty new malignant tumours were found in 1080 patients (634 men, 446 women; mean age 37.6 +/- 13.6 years) after a median follow-up period of 5 years following 1245 cadaveric kidney transplantations performed between 1972 and 1990. The mean dialysis period before transplantation had been 4.0 +/- 3.1 years. Regarding the type of tumour, carcinomas were by far the most frequent, while there was only one lymphoma. The annual malignancy incidence for renal transplant patients was 0.5%. This is 3.5 times higher for men and 4.2 times for women than in the normal population. Immunosuppression with azathioprine and/or antithymocytic globulin (n = 395) produced the same malignancy incidence (0.54%) as with cyclosporin (n = 685; 0.60%). On the other hand, malignant tumours occurred much earlier under cyclosporin than under azathioprine/antithymocytic globulin (27 and 68 months, respectively).
    DMW - Deutsche Medizinische Wochenschrift 07/1992; 117(24):927-34. · 0.55 Impact Factor
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    ABSTRACT: OKT3 has been proved to be effective in the treatment of steroid-resistant rejection after renal allograft transplantation. We investigated the clinical course of OKT3 recipients to find out in which cases of steroid resistance OKT3 therapy might be ineffective.
    Transplant International 02/1992; 5 Suppl 1:S112-3. · 3.16 Impact Factor
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    ABSTRACT: The introduction of immunosuppression with cyclosporine A in 1983 compared to conventional immunosuppression has clearly improved early results within the first year post transplant. In contrast, the rate of graft failure per year in the following course has not changed essentially. Still HLA histocompatibility is a predominant prognostic factor which can be influenced by organ sharing. On the other hand, donor factors like sex and age are becoming more important and should be taken into account for organ allocation. This furthermore requires strict attention to future exchange rules within the transplant community.
    Langenbecks Archiv für Chirurgie. Supplement. Kongressband. Deutsche Gesellschaft für Chirurgie. Kongress 02/1992;
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    ABSTRACT: An 83-amino acid cholecystokinin peptide with a sulfated tyrosine and an amidated carboxyl terminus (CCK-83) was purified from human intestinal mucosa. The purified peptide was chemically characterized, and its bioactivity was compared to CCK-8. Several post-translational processing steps such as cleavage at basic residues, sulfation, and amidation are necessary to form biologically active cholecystokinin from its nascent prepropeptide. The discovery of CCK-83 gives new insight into the order of preprohormone processing. The processing of prepro-CCK appears to be in the order of: 1) signal peptidase cleavage, 2) tyrosine sulfation, 3) cleavage after a carboxyl-terminal pair of basic residues, 4) carboxypeptidase B-like cleavage of these basic residues, 5) amidation (which results in the formation of CCK-83), and 6) cleavage at monobasic residues by endopeptidases (which results in the smaller molecular forms of cholecystokinin). The characterization of biologically active CCK-83 with a sulfated tyrosine and an amidated carboxyl terminus establishes the site of signal peptidase action and suggests an order of post-translational modifications that give rise to the various molecular forms of cholecystokinin.
    Journal of Biological Chemistry 02/1992; 267(3):1517-21. · 4.60 Impact Factor
  • DMW - Deutsche Medizinische Wochenschrift 01/1992; 117(24):927-934. DOI:10.1055/s-2008-1062393 · 0.55 Impact Factor
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    ABSTRACT: To elucidate the role of hormones in the control of pancreatic secretion, we developed, in seven dogs, a model of total extrinsic denervation of the jejunoileum by autotransplanting this segment of bowel. A Thomas-like cannula was placed into the stomach, the duodenum (to collect pure pancreatic juice), and the proximal part of the jejunum. Thus, intestinal stimulants could only stimulate the pancreas via release of humoral (= hormonal) mediators. Seven control dogs received only the three fistulas. After recovery, dose-response curves of pancreatic bicarbonate and protein response to perfusion of the extrinsically denervated or innervated jejunoileum with HCl (1.5 to 48 mmol h-1) were performed with and without atropine (14 nmol kg-1 h-1 i.v.). Plasma levels of secretin were determined by radioimmunoassay. The maximal bicarbonate output occurred in response to 24 mmol h-1 of HCl and was significantly (p less than 0.05) higher in intact as compared to denervated animals. Atropine only significantly depressed the bicarbonate response to HCl in dogs with a denervated jejunoileum. HCl caused a dose-dependent increase in plasma levels of secretin, which was not altered by denervation and/or atropine. Irrespective of the innervation of the small bowel, pancreatic protein output was only significantly stimulated above basal when high loads (12-48 mmol h-1) of HCl were given. Atropine significantly reduced these responses.(ABSTRACT TRUNCATED AT 250 WORDS)
    Pancreas 06/1991; 6(3):341-9. · 3.01 Impact Factor
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    ABSTRACT: Veno-venous bypass during orthotopic liver transplantation is commonly performed as a porto-femoro-axillary bypass. Right-angle positioning of one patient's arm and surgical preparation of the femoral and axillary veins are necessary. In 17 patients and 20 consecutive orthotopic liver transplant procedures the common porto-femoro-axillary veno-venous bypass was substituted by porto-femoro-subclavian bypass with a percutaneous 20 F cannulation set (LAUB catheter, Cook). The 20 F catheter was introduced into the left subclavian vein by Seldinger's technique before the operation and was connected intraoperatively to the outflow tube of the biopump. Surgical preparation of the axillary vein was not performed. In 10 patients a Y-connector was used to connect up the Rapid Infusion System in addition. Postoperatively the catheter was left in place for 2-4 days. Introduction and removal of the catheter were uneventful in all cases. High blood flow through the catheter could be maintained by a low driving pressure of the pump (4000 ml/min; 100 mmHg). No intraoperative complications were observed. Shunt flows remained stable throughout the surgical procedure during the anhepatic stage. There was no bleeding from the puncture site, especially after removal of the catheter, though several patients had a poor coagulatory status in the early postoperative period. Two postoperative complications were observed: air embolism due to disconnection and formation of a thrombus at the catheter tip, which it was possible to remove together with the catheter itself. Installation of an irrigation infusion in the postoperative period and well-tightened connections help avoid such complications as thrombus formation, bleeding or air embolism.(ABSTRACT TRUNCATED AT 250 WORDS)
    Der Anaesthesist 05/1991; 40(4):222-8. · 0.74 Impact Factor
  • W Niebel, L C Olivier, J Erhard
    Zeitschrift für Gastroenterologie. Verhandlungsband 04/1991; 26:80-1.

Publication Stats

458 Citations
169.45 Total Impact Points

Institutions

  • 1981–2012
    • University of Duisburg-Essen
      Essen, North Rhine-Westphalia, Germany
  • 1983–1992
    • University Hospital Essen
      Essen, North Rhine-Westphalia, Germany
  • 1990
    • Harbor-UCLA Medical Center
      Torrance, California, United States