Publications by authors named "Clemens Friedrich Hess"

The mechanisms of radiation-induced liver damage are poorly understood. We investigated if tumour necrosis factor (TNF)-α acts synergistically with irradiation, and how its activity is influenced by platelet endothelial cell adhesion molecule-1 (PECAM-1). We studied murine models of selective single-dose (25 Gy) liver irradiation with and without TNF-α application (2 μg/mouse; i.

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Platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) is known to play an important role in hepatic inflammation. Therefore, we investigated the role of PECAM-1 in wild-type (WT) and knock-out (KO)-mice after single-dose liver irradiation (25 Gy). Both, at mRNA and protein level, a time-dependent decrease in hepatic PECAM-1, corresponding to an increase in intercellular cell adhesion molecule-1 (ICAM-1) (6 hrs) was detected in WT-mice after irradiation.

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Irradiation is known to induce inflammation and affect fat metabolic pathways. The current study investigates hepatic fat accumulation and fatty acid transportation in a rat model of single dose liver irradiation (25-Gy). Rat livers were selectively irradiated in-vivo (25-Gy), sham-irradiated rats served as controls.

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Introduction: The CAO/ARO/AIO-94 phase-III-trial demonstrated a significant improvement of preoperative chemoradiotherapy (CRT) versus postoperative CRT on local control for UICC stage II/III rectal cancer patients, but no effect on long-term survival. In this add-on evaluation, we investigated the association of gender and age with acute toxicity and outcome.

Patients And Methods: According to actual treatment analyses, 654 of 799 patients had received pre- (n=406) or postoperative CRT (n=248); in 145 patients postoperative CRT was not applied.

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The liver is considered a radiosensitive organ. However, in rats, high single-dose irradiation (HDI) showed only mild effects. Consequences of fractionated irradiation (FI) in such an animal model have not been studied so far.

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The current study aimed to investigate radiation-induced regulation of iron proteins including ferritin subunits in rats. Rat livers were selectively irradiated in vivo at 25 Gy. This dose can be used to model radiation effects to the liver without inducing overt radiation-induced liver disease.

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Background And Purpose: Ongoing clinical trials aim to improve local control and overall survival rates by intensification of therapy regimen for patients with locally advanced rectal cancer. It is well known that whenever treatment is intensified, risk of therapy-related toxicity rises. An irradiation with protons could possibly present an approach to solve this dilemma by lowering the exposure to the organs-at-risk (OAR) without compromising tumor response.

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Purpose: Transforming growth factor-beta1 is related to adverse events in radiochemotherapy. We investigated TGFB1 genetic variability in relation to quality of life-impairing acute organ toxicity (QAOT) of neoadjuvant radiochemotherapy under clinical trial conditions.

Methods And Materials: Two independent patient cohorts (n = 88 and n = 75) diagnosed with International Union Against Cancer stage II/III rectal cancer received neoadjuvant radiation doses of 50.

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Article Synopsis
  • Hepatocyte transplantation shows promise for treating chronic liver failure by repopulating diseased livers, with previous research indicating success using a high radiation dose (25 Gy) in rats.
  • The study explored the effects of lower radiation doses and fractionated irradiation protocols (e.g., 5 × 5 Gy) on liver repopulation, comparing them to standard treatments in DPPIV-deficient rats.
  • Results indicated that higher radiation doses and the fractionated approach led to better integration of donor liver cells and larger cell clusters, while lower doses were significantly less effective, suggesting potential clinical application for fractionated radiotherapy before transplantation.
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Purpose: The goal of the interdisciplinary Clinical Research Unit KFO179 (Biological Basis of Individual Tumor Response in Patients with Rectal Cancer) is to develop an individual Response and Toxicity Score for patients with locally advanced rectal cancer treated with neoadjuvant radiochemotherapy. The aim of the present study was to find a reliable and sensitive method with easy scoring criteria and high numbers of cell counts in a short period of time in order to analyze DNA damage in peripheral blood lymphocytes. Thus, the cytokinesis-block micronucleus (CBMN) assay and the chromosome aberration technique (CAT) were tested.

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Purpose: To test for a possible correlation between high-grade acute organ toxicity during primary radiochemotherapy and treatment outcome for patients with anal carcinoma.

Methods And Materials: From 1991 to 2009, 72 patients with anal carcinoma were treated at our department (10 patients had stage I, 28 patients had stage II, 11 patients had stage IIIA, and 13 patients had stage IIIB cancer [Union Internationale Contre le Cancer criteria]). All patients received normofractionated (1.

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Liver damage is a serious clinical complication of gamma-irradiation. We therefore exposed rats to single-dose gamma-irradiation (25 Gy) that was focused on the liver. Three to six hours after irradiation, an increased number of neutrophils (but not mononuclear phagocytes) was observed by immunohistochemistry to be attached to portal vessels between and around the portal (myo)fibroblasts (smooth muscle actin and Thy-1(+) cells).

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Purpose: To test for a possible correlation between high-grade acute organ toxicity during preoperative radiochemotherapy and complete tumor regression after total mesorectal excision in multimodal treatment of locally advanced rectal cancer.

Patients And Methods: From 2001 to 2008, 120 patients were treated. Preoperative treatment consisted of normofractionated radiotherapy at a total dose of 50.

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Background And Purpose: Migration of leukocytes into tissue is a key element of innate and adaptive immunity. An animal study showed that liver irradiation, in spite of induction of chemokine gene expression, does not lead to recruitment of leukocytes into the parenchyma. The aim of this study was to analyze gene expression of adhesion molecules, which mediate leukocyte recruitment into organs, in irradiated rat liver in vivo and rat hepatocytes in vitro.

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Purpose: To evaluate prostate volume changes during external-beam irradiation in consequence of high-dose-rate (HDR) brachytherapy in prostate cancer treatment.

Patients And Methods: 20 patients who underwent radiotherapy for prostate cancer were included in this prospective evaluation. All patients had a computed tomography (CT) scan for planning of the external-beam irradiation and additional scans after each HDR brachytherapy.

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Near infrared fluorescence (NIRF) optical imaging is a technique particularly powerful when studying in vivo processes at the molecular level in preclinical animal models. We recently demonstrated liver irradiation under the additional stimulus of partial hepatectomy as being an effective primer in the rat liver repopulation model based on hepatocyte transplantation. The purpose of this study was to assess optical imaging and the feasibility of donor cell expansion tracking in vivo using a fluorescent probe.

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A phantom study for dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer is presented. The measurement method of the secondary standard of the Physikalisch-Technische Bundesanstalt had to be slightly modified in order to be able to measure inside a Foley catheter. The absorbed dose to water response of the alanine dosimetry system to (192)Ir was determined with a reproducibility of 1.

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Purpose: Differences in the delineation of the gross target volume (GTV) and planning target volume (PTV) in patients with non-small-cell lung cancer are considerable. The focus of this work is on the analysis of observer-related reasons while controlling for other variables.

Methods: In three consecutive patients, eighteen physicians from fourteen different departments delineated the GTV and PTV in CT-slices using a detailed instruction for target delineation.

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Background And Purpose: In locally advanced rectal cancer, neoadjuvant radiochemotherapy is indicated. To improve target volume definition for radiotherapy planning, the potential of implanted gold markers in the tumor region was evaluated.

Patients And Methods: In nine consecutive patients, two to three gold markers were implanted in the tumor region during rigid rectoscopy.

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Background: Tumour necrosis factor alpha (TNF-alpha) may exhibit antitumoral activity and can influence the reaction of both tumour and normal tissue to radiation.

Aims: To test the effect of TNF-alpha and/or irradiation on hepatocellular (HepG2, Hep3B, Sk-Hep1, HuH7) and cholangiocellular (Sk-chA1, Mz-chA1) tumour cell lines.

Methods: Colony formation, apoptosis analysis and trypan blue exclusion were used to assess cell viability.

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Article Synopsis
  • Near infrared fluorescence (NIRF) imaging is effective for studying molecular processes in living animal models, specifically targeting liver repopulation after transplantation in a rat model.* -
  • In the study, DPPIV-deficient rats had their livers preconditioned with irradiation, followed by partial hepatectomy and transplantation of wild-type hepatocytes, enabling tracking of donor cell repopulation using a specialized fluorescent probe.* -
  • Results showed significant donor cell growth and repopulation, detected through optical imaging, which suggests optical imaging could play a vital role in future liver transplantation protocols using fluorescent dyes and technologies.*
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Purpose: : For radiation treatment of patients with cervical cancer and a high risk for paraaortic lymph node involvement, an easy three-dimensional (3-D) conformal irradiation technique (partial half-beam [PHB]) for protection of organs at risk, especially of renal tissue, was developed.

Patients And Methods: : In five consecutive female patients a computed tomography scan was performed. Dose-volume histograms of the renal tissue and other organs at risk were analyzed for PHB, three other 3-D conformal techniques, and an intensitymodulated radiotherapy (IMRT) technique.

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Purpose: We have developed a device to evaluate the potential of alanine/electron spin resonance (ESR) dosimetry for quality assurance in 3D conformal radiotherapy for prostate cancer. It consists of a rectal balloon carrying eight alanine dosimeter probes and two metal markers to document the exact position of the balloon. We measured the effects of an air-filled rectal balloon on the dose at the rectal wall and compared these results with the applied dose distribution of the treatment planning system.

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Article Synopsis
  • Hepatocyte transplantation after liver irradiation and partial hepatectomy shows significant liver repopulation, but the study uncovers how irradiation affects the regenerative capacity of native liver cells.
  • Rat livers underwent irradiation and partial hepatectomy, with analysis over time revealing changes in DNA damage, apoptosis, and gene expression.
  • The research found that while DNA damage from irradiation was temporary and apoptosis was minimal, the resulting increase in certain protein levels led to a prolonged halt in the cell cycle, which may favor the growth of transplanted liver cells.
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The aim of the study was to analyze the effect of a single irradiation on chemokine gene expression in the rat liver and in isolated rat hepatocytes. RNA extracted from livers and from hepatocytes within the first 48 h after irradiation was analyzed by real-time PCR and the Northern blot assay. The chemokine concentrations in the serum of irradiated rats were measured quantitatively by ELISA.

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