Biomedical subjects

Dirk Uhlmann

Publications and source records attributed to Dirk Uhlmann.

23 records · Page 2Linked to original sources

PubMed2001

Neuroendocrine tumours of the duodenum. Clinical aspects, pathomorphology and therapy.

BACKGROUND AND AIMS: Neuroendocrine tumours (NTs) of the duodenum are uncommon neoplasms. They represent a heterogeneous spectrum of subtypes and may be associated with von Recklinghausen's disease type I (VRD) and multiple endocrine neoplasia type I. There are few studies concerning the biological characteristics and adequate therapy of these tumours. PATIENTS AND METHODS: We report on a retrospective analysis of 12 patients with NTs of the duodenum: six non-ampullary (naNTs) and six ampullary tumours (aNTs). These patients were treated between January 1992 and January 2001. Clinical and histopathological features, therapy and follow-up were evaluated retrospectively and compared with the literature. RESULTS: All tumours were located in the first and second portions of the duodenum. Three of six aNTs presented with jaundice, and four of six naNTs were incidental findings. Two patients with naNTs showed Zollinger-Ellison syndrome and two with aNTs VRD. Of the six patients with naNTs, four were treated by local excision (two endoscopically, two surgical resection), one by Kausch-Whipple operation and in one patient the tumour was an incidental finding in the Billroth II specimen. Four of the six patients with aNTs underwent Kausch-Whipple procedure, one patient ampullectomy (gangliocytic paraganglioma) and one patient palliative chemotherapy. The size of the naNTs were less than 0.6 cm, whereas the size of the aNTs ranged from 1.5 cm to 4 cm. Tumour size of aNTs had no correlation with depth of invasion and metastases. Metastases were found in two aNTs and none of the naNTs. Immunohistochemically tumour cells expressed somatostatin in 5 of 6 aNTs and gastrin in 1 of 6 aNTs and in two gastrinomas. There was no hospital mortality. Two patients died for reasons not related to the tumour. Tumour excision of both patients with gastrinomas was not curative. Three patients with naNTs and four with aNTs are alive without disease. One patient with palliative treatment of a metastasising aNT is alive 66 months after diagnosis. CONCLUSION: Non-ampullary duodenal NTs differ clinically, histologically and immunohistochemically as well as with respect to the extent of resection from NTs of the ampulla of Vater.

Adult↗

PubMedDate not supplied

Management and outcome in patients with Klatskin-mimicking lesions of the biliary tree.

The preoperative and even intraoperative differentiation between benign and malignant strictures at the hepatic hilum remains difficult. The aim of this study was to assess clinical, radiologic, intraoperative, and histopathologic findings; surgical treatment; and outcome of patients with Klatskin mimicking benign lesions. Of 49 consecutive patients who were operated on the initial preoperative radiologic diagnosis of hilar adenocarcinoma (Klatskin tumor), 7 (14%) had benign conditions after final histopathologic diagnosis. Pretreatment work-up, therapy, and outcome of these patients were analyzed. Based on preoperative clinical symptoms, imaging assessment, and CA19-9 values, all seven patients were classified as having malignant neoplasms. At laparotomy, the tumors of six patients were judged to be malignant. Five patients underwent hilar resection and concomitant liver resection, and two patients underwent hilar resection alone. There were no operative deaths. The definitive histopathologic examination showed severe cholangitis with extensive periductal fibrosis in all patients. After a median follow-up of 32 months, all patients are well. Clinical presentation and imaging assessment were similar for Klatskin tumors and benign fibrosing disease; therefore, an aggressive resectional approach is justified in any patient with suspicious obstruction of the liver hilum.

Adult↗

PubMedDate not supplied

Quality of life in chronic pancreatitis: a prospective trial comparing classical whipple procedure and duodenum-preserving pancreatic head resection.

Few data are available with respect to quality of life after pancreatic head resection in patients with chronic pancreatitis. The aim of this study was to compare the classical Whipple pancreatoduodenectomy (PD) with the Beger duodenum-preserving pancreatic head resection (DPPHR), in terms of quality of life, using standardized, valid, and reliable questionnaires. Sixty-five consecutive patients were included in this study. The PD procedure was chosen when pancreatic cancer could not be ruled out (n = 30); otherwise DPPHR was performed (n = 35). Quality of life was measured prospectively three times with the European Organization for Research and Treatment of Cancer (EORTC) Quality-of-Life Questionnaire (QLQ-C30) and the Gastrointestinal Quality-of-Life Index (GIQLI). Both procedures led to a significant improvement in quality of life, especially with regard to pain status. However, at the second follow-up examination (18 to 24 months postoperatively), all functional scales and the most important symptom scales of the EORTC QLQ-C30 revealed a better quality of life in the DPPHR group compared to the PD group. After classical PD, more patients seem to develop diabetes mellitus. The EORTC QLQ-C30 was found to be a better tool for quality-of-life assessment than the GIQLI in patients with chronic pancreatitis.

Chronic Disease↗

PubMedDate not supplied

Endothelin A receptor blockade reduces hepatic ischemia/reperfusion injury after warm ischemia in a pig model.

It is well established that endothelin-1 (ET-1) is a very potent mediator of vasoconstriction that leads to microcirculatory disturbances. The aim of the study was to evaluate the effect of a selective endothelin A receptor antagonist on severe ischemia/reperfusion injury in a pig model. Fourteen pigs were subjected to 120 minutes of complete vascular exclusion of the liver with a passive bypass. The animals were randomized into two groups: a control group, which was given isotonic saline solution, and a therapy group, which received the selective endothelin A receptor antagonist BSF 208075 at the beginning of reperfusion. On postoperative days 4 and 7, animals were relaparotomized to obtain tissue specimens. Blood monitoring included aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), alkaline phosphatase, and ET-1. Partial oxygen tension (p(ti)O(2)) was measured by a Clarke-type electrode and blood flow by laser Doppler. A semiquantitative scoring index was used for assessment of histologic injury and for immunohistochemical analysis of ET-1. Treatment with the endothelin A receptor antagonist significantly reduced the severity of the ischemia/reperfusion injury, as evidenced by lower levels of AST, ALT, and GLDH. The dramatic increase in plasma ET-1 in the therapy group is clear evidence of effective receptor blockade. Analysis of p(ti)O(2) and blood flow revealed a significant improvement in capillary perfusion and blood flow in the treated group and was associated with relevant reduction of tissue injury. In summary, in the control group we observed serious microcirculatory disturbances and severe histologic damage in the liver after reperfusion. Treatment with a selective endothelin A receptor antagonist attenuated the ischemia/reperfusion injury in a porcine model of severe ischemia/reperfusion, as demonstrated by improved microcirculation, a reduction in histologic damage, and an decrease in liver enzymes.

Alanine Transaminase↗

PubMedDate not supplied

Effects of ET(A) receptor antagonism on proinflammatory gene expression and microcirculation following hepatic ischemia/reperfusion.

BACKGROUND: The objective of this study was to investigate the effect of a specific endothelin(A) receptor antagonist (ET(A)-RA) on mRNA expression of genes encoding vasoactive mediators and proinflammatory cytokines and on the microhemodynamics (assessed by measurement of laser Doppler flow and tissue blood gases) following complete vascular exclusion of the porcine liver. STUDY DESIGN: Sixteen adult German landrace pigs were subjected to 120 min of warm hepatic ischemia by total vascular exclusion. To avoid portal congestion, a passive porto-femoro/jugular bypass was implanted. The animals were divided into 2 groups: the control group received saline solution and the therapy group was given the selective ET(A)-RA BSF 208075. Hepatic microcirculation was evaluated by p(O(2)) and p(CO(2)) measurement with the Paratrend sensor and by laser Doppler flow measurement. Liver tissue samples were collected 1 h after reperfusion and quantitative mRNA expression for prepro-ET-1, pro-IL-1beta, pro-IL-6, pro-TNF-alpha, eNOS was analyzed using the TaqMan system. Additionally, immunohistochemical analysis using a semiquantitative score for ET-1 was performed. Postischemic liver damage was monitored by measurement of liver enzymes and assessed by histological analysis using a semiquantitative scoring classification. RESULTS: Partial oxygen pressure in the hepatic tissue and laser Doppler flow were significantly improved in the therapy group. One hour after reperfusion, quantitative RT-PCR revealed significantly lower expression of prepro-ET-1, eNOS, pro-TNF-alpha, and pro-IL-6 in the therapy group compared to controls. Immunohistochemical analysis demonstrated significantly reduced ET-1 immunostaining after therapy. Furthermore, blockade of ET(A) receptors prevents tissue damage. CONCLUSIONS: Treatment with the selective ET(A)-RA BSF 208075 has protective effects on microcirculation after 120 min liver ischemia and reperfusion. The authors were able to show that ET(A)-RA not only affects the expression of vasoactive genes, but also decreases gene expression of proinflammatory cytokines such as TNF-alpha and IL-6.

Animals↗