Biomedical subjects

Stefan Heinrich

Publications and source records attributed to Stefan Heinrich.

9 recordsLinked to original sources

PubMed2006

Portal vein ligation and partial hepatectomy differentially influence growth of intrahepatic metastasis and liver regeneration in mice.

BACKGROUND/AIMS: Since modern treatment of liver metastases includes serial hepatectomies and portal vein obstruction, we investigated the effects of portal vein ligation (PVL) and partial hepatectomy (PH) on tumor growth. METHODS: The effects of 70% PH and PVL on liver and lung metastases were evaluated in mice. Tumor growth and liver regeneration were assessed by morphometry and immunohistochemistry for PCNA and BrdU. The effect of growth factors of liver regeneration on CT-26 cells was tested in vitro, and TGF-beta secretion of CT-26 cells was measured by ELISA. RNA synthesis of TGF-beta and activin A was measured by RT-PCR. RESULTS: Liver regeneration after PH and PVL was similar in tumor-free mice. Intrahepatic tumor growth was lower after PH than after PVL (p=0.016). Extrahepatic tumor growth was not different. In contrast to PVL, liver regeneration was delayed after PH in metastatic livers (p=0.001). Tested growth factors of liver regeneration stimulated CT-26 cells in vitro, and CT-26 secreted significant amounts of TGF-beta in vitro and in vivo. CONCLUSIONS: Although similar in tumor-free mice, liver regeneration significantly differed between PVL and PH in metastatic livers. In addition, PH and PVL differently affected intrahepatic tumor growth.

Animals↗

PubMed2006

Evidence-based treatment of acute pancreatitis: a look at established paradigms.

BACKGROUND: The management of acute pancreatitis (AP) is still based on speculative and unproven paradigms in many centers. Therefore, we performed an evidence-based analysis to assess the best available treatment. METHODS: A comprehensive Medline and Cochrane Library search was performed evaluating the indication and timing of interventional and surgical approaches, and the value of aprotinin, lexipafant, gabexate mesylate, and octreotide treatment. Each study was ranked according to the evidence-based methodology of Sackett; whenever feasible, we performed new meta-analyses using the random-effects model. Recommendations were based on the available level of evidence (A=large randomized; B=small randomized; C=prospective trial). RESULTS: None of the evaluated medical treatments is recommended (level A). Patients with AP should receive early enteral nutrition (level B). While mild biliary AP is best treated by primary cholecystectomy (level B), patients with severe biliary AP require emergency endoscopic papillotomy followed by interval cholecystectomy (level A). Patients with necrotizing AP should receive imipenem or meropenem prophylaxis to decrease the risk of infected necrosis and mortality (level A). Sterile necrosis per se is not an indication for surgery (level C), and not all patients with infected necrosis require immediate surgery (level B). In general, early necrosectomy should be avoided (level B), and single necrosectomy with postoperative lavage should be preferred over "open-packing" because of fewer complications with comparable mortality rates (level C). CONCLUSIONS: While providing new insights into key aspects of AP management, this evidence-based analysis highlights the need for further clinical trials, particularly regarding the indications for antibiotic prophylaxis and surgery.

Acute Disease↗

PubMed2005

Positron emission tomography/computed tomography influences on the management of resectable pancreatic cancer and its cost-effectiveness.

OBJECTIVE: We sought to determine the impact of positron emission tomography/computed tomography (PET/CT) on the management of presumed resectable pancreatic cancer and to assess the cost of this new staging procedure. SUMMARY BACKGROUND DATA: PET using 18F-fluorodeoxyglucose (FDG) is increasingly used for the staging of pancreatic cancer, but anatomic information is limited. Integrated PET/CT enables optimal anatomic delineation of PET findings and identification of FDG-negative lesions on computed tomography (CT) images and might improve preoperative staging. MATERIAL AND METHODS: Patients with suspected pancreatic cancer who had a PET/CT between June 2001 to April 2004 were entered into a prospective database. Routine staging included abdominal CT, chest x-ray, and CA 19-9 measurement. FDG-PET/CT was conducted according to a standardized protocol, and findings were confirmed by histology. Cost benefit analysis was performed based on charged cost of PET/CT and pancreatic resection and included the time frame of staging and surgery. RESULTS: Fifty-nine patients with a median age of 61 years (range, 40-80 years) were included in this analysis. Fifty-one patients had lesions in the head and 8 in the tail of the pancreas. The positive and negative predictive values for pancreatic cancer were 91% and 64%, respectively. PET/CT detected additional distant metastases in 5 and synchronous rectal cancer in 2 patients. PET/CT findings changed the management in 16% of patients with pancreatic cancer deemed resectable after routine staging (P = 0.031) and was cost saving. CONCLUSIONS: PET/CT represents an important staging procedure prior to pancreatic resection for cancer, since it significantly improves patient selection and is cost-effective.

Adenocarcinoma↗

PubMed2004

Indocyanine green angiography and fluorescein angiography of malignant choroidal melanomas following proton beam irradiation.

BACKGROUND: The vascularisation features of intraocular tumours may be characterised by indocyanine green angiography (ICG-A) and fluorescein angiography (FA). Proton beam irradiation is an established method of treating malignant melanoma of the choroid. The aim of this study was to describe the vascularisation features of small choroidal melanomas and to examine the influence of proton beam irradiation on these tumours. METHODS: We examined 39 choroidal melanomas by ICG-A and FA from 1998 to 2001 in a prospective study. The tumours had a mean prominence of 3.65 mm (1.2-7.5 mm) and a common feature of all was their parapapillary or paramacular localisation. Angiography was always performed immediately before proton beam radiotherapy and at intervals of 3 months, half a year and 1 year thereafter. Two hundred and forty angiographies were analysed in total. RESULTS: Intra-tumoral vessels could be visualised in 89% of all tumours by ICG angiography but in only 33% by FA. Neither ICG-A nor FA detected changes 3 months after irradiation; however, ICG-A disclosed strong leakage from vessels in the tumour area after 6 months. These changes increased markedly after 12 months and were also visible by FA. A disadvantage of FA, however, was the faster escape of dye from the vessels, which caused rapid leakage in the tumour area and meant that details could no longer be demonstrated. CONCLUSIONS: ICG-A and FA detect marked vascular changes within the tumours examined.

Choroid Neoplasms↗

PubMed2004

Ischemic preconditioning and intermittent clamping improve murine hepatic microcirculation and Kupffer cell function after ischemic injury.

The aim of this study was to evaluate whether the protective effect of intermittent clamping and ischemic preconditioning is related to an improved hepatic microcirculation after ischemia/reperfusion injury. Male C57BL/6 mice were subjected to 75 or 120 min of hepatic ischemia and 1 or 3 hours of reperfusion. The effects of continuous ischemia, intermittent clamping, and ischemic preconditioning before prolonged ischemia on sinusoidal perfusion, leukocyte-endothelial interactions, and Kupffer cell phagocytic activity were analyzed by intravital fluorescence microscopy. Kupffer cell activation was measured by tissue levels of tumor necrosis factor (TNF)-alpha, and the integrity of sinusoidal endothelial cells and Kupffer cells were evaluated by electron microscopy. Continuous ischemia resulted in decreased sinusoidal perfusion rate and phagocytic activity of Kupffer cell, increased leukocyte-endothelial interactions and TNF-alpha levels. Both protective strategies improved sinusoidal perfusion, leukocyte-endothelial interactions and phagocytic activity of Kupffer cells after 75-minutes of ischemia, and intermittent clamping also after 120 minutes ischemia. TNF-alpha release was significantly reduced and sinusoidal wall integrity was preserved by both protective procedures. In conclusion, both strategies are protective against ischemia/reperfusion injury by maintaining hepatic microcirculation and decreasing Kupffer cell activation for clinically relevant ischemic periods, and intermittent clamping appears superior for prolonged ischemia.

Animals↗

PubMed2004

Retroperitoneal perforation of the colon caused by colonic tuberculosis: report of a case.

We present a 25-year-old, HIV-negative patient from Kosovo, with no significant past medical history, who was admitted to a local hospital for nonspecific upper abdominal discomfort. He was transferred to us after a retroperitoneal mass with contact to the right colonic flexure had been found during workup. Colonoscopy demonstrated an edemateous area with a central fistula in the right flexure, and histology showed caseous necrosis. Although neither bacteriology nor histology could detect any germs, gastrointestinal tuberculosis seemed to be very probable. Laparotomy with a segmental resection of the colon was performed to remove the fistula-bearing segment, and histologic examination of the resected specimen confirmed the intraoperative suspect of a retroperitoneal colonic perforation. Again, all cultures from the specimen were negative for tuberculosis, but polymerase chain reaction of a regional lymph node revealed acid-fast bacilli of the Mycobacterium tuberculosis/bovis species. Although the patient had no other sites of tuberculosis infection like pulmonary or urinary, he received adjuvant standard tuberculosis treatment for six months. At control examination one year after the operation, the patient was free of recurrence and in very good general condition. We report this extremely rare presentation of gastrointestinal tuberculosis to sensitize physicians to tuberculosis again, because incidence rates are increasing and this disease will certainly play a more important role in the future.

Abdominal Pain↗

PubMed2003

Technical complications of continuous intra-arterial chemotherapy with 5-fluorodeoxyuridine and 5-fluorouracil for colorectal liver metastases.

BACKGROUND: Intra-arterial chemotherapy is an effective modality to treat unresectable hepatic metastases from colorectal primaries if systemic chemotherapy has failed. Response rates of more than 40% and a median survival of 15 to 25 months have been reported from randomized trials. In this retrospective study, we analyzed specific technical complications associated with continuous intra-arterial chemotherapy for colorectal liver metastases. METHODS: From 1982 to 1995, single-center clinical data from 180 patients with colorectal liver metastases were evaluated. Continuous intra-arterial chemotherapy was administered using either an implanted infusion pump or an intra-arterial port with an external infusion pump. The intra-arterial catheter was implanted according to the Watkins' technique. The treatment protocols consisted of 5-fluorouracil- or 5-fluorodeoxyuridine-based regimens. RESULTS: A total of 70 patients (39%) received an intra-arterial infusion pump and 110 patients (61%) an intra-arterial port. Sixty-eight technical complications affected port systems (62%), whereas 29 patients with pumps (41%) were affected by technical complications. Therapy-relevant complications were observed in 47% of the ports and 30% of the infusion pumps. The median complication-free survival was 12.2 months for infusion pumps and 7.3 months for ports (P =.0016). CONCLUSIONS: Our data demonstrate that pumps are superior to ports in terms of complication rate and complication-free survival. On the basis of our results, pumps have a potential for a longer treatment, which may result in a prolonged median survival.

Antimetabolites, Antineoplastic↗

PubMed2002

Regional chemotherapy.

Regional chemotherapy is an interesting treatment option in patients with advanced pancreatic cancer but cannot be considered standard treatment, and it should not be performed outside controlled clinical trials. The real value of regional chemotherapy must be evaluated in larger, randomized trials. New drug combinations may reduce the observed side effects and improve tumor response. Gene therapy with p53 and K-ras modulated herpesviruses may become a palliative treatment option and can be administered easily by regional chemotherapy techniques [23].

Adenocarcinoma↗

PubMed2002

Second liver resections are safe and effective treatment for recurrent hepatic metastases from colorectal cancer: a bi-institutional analysis.

OBJECTIVE: To determine the value of repeat liver resection for recurrent colorectal metastases to the liver. SUMMARY BACKGROUND DATA: Liver resection represents the best and a potentially curative treatment for metastatic colorectal cancer to the liver. After resection, however, most patients develop recurrent disease, often isolated to the liver. METHODS: This study reports the combined experience of repeat liver resection for recurrent liver metastases at an American and a European surgical oncology center. Patients were identified from prospective databases and records were retrospectively reviewed. A total of 126 patients (American n = 96, 1986-2001; European n = 30, 1985-1999) underwent repeat liver resection. Patient characteristics were similar in the two institutions. Median follow-up from first liver resection was 88 and 105 months, respectively. RESULTS: Operations performed included 90 minor resections and 36 resections of a lobe or more. The 1-, 3-, and 5-year survival rates were 86%, 51%, and 34%. There were 19 actual 5-year survivors to date. By multivariate regression analysis (proportional hazard model), more than one lesion and tumor size larger than 5 cm were independent prognostic indicators of reduced survival. The interval between the first and second liver resection was not predictive of outcome. CONCLUSIONS: Repeat liver resection for colorectal liver metastases is safe. Patients with a low tumor load are the best candidates for a repeat resection. In well-selected patients, further resection of the liver can provide prolonged survival after recurrence of colorectal liver metastases.

Adult↗