Realising the European Network of Biodosimetry (RENEB).

In Europe, a network for biological dosimetry has been created to strengthen the emergency preparedness and response capabilities in case of a large-scale nuclear accident or radiological emergency. Through the RENEB (Realising the European Network of Biodosimetry) project, 23 experienced laboratories from 16 European countries will establish a sustainable network for rapid, comprehensive and standardised biodosimetry provision that would be urgently required in an emergency situation on European ground. The foundation of the network is formed by five main pillars: (1) the ad hoc operational basis, (2) a basis of future developments, (3) an effective quality-management system, (4) arrangements to guarantee long-term sustainability and (5) awareness of the existence of RENEB. RENEB will thus provide a mechanism for quick, efficient and reliable support within the European radiation emergency management. The scientific basis of RENEB will concurrently contribute to increased safety in the field of radiation protection.

Evaluation of perioperative cholangiography in one thousand laparoscopic cholecystectomies.

We analyzed a teaching institution's experience with intra-operative cholangiography (IOCG) and endoscopic retrograde cholangiopancreatography (ERCP) and established an algorithm for their timing and use. The records of all patients undergoing LC during a five year period were reviewed. Patients with a history of jaundice or pancreatitis, abnormal bilirubin, alkaline phosphatase, serum glutamic-oxaloacetic transaminase, or radiographic evidence suggestive of choledocholithiasis were considered "at risk" for common bile duct stones (CBDS). The remaining patients were considered to be at low "risk." LC was attempted on 1002 patients during the study period and successfully completed on 941 (94% of the time). The major complication rate was 3.1% and the common bile duct injury rate 0.1%. Eighty eight (9.5%) patients underwent ERCP, 67 in the preoperative period and 19 in the postoperative period. IOCG was attempted in 272 (24%) patients and completed in 234 for a success rate of 86%. Intraoperative cholangiography (IOCG) and preoperative endoscopic retrograde cholangiopancreatography (ERCP) were equivalent in the detection of CBDSs Twelve of the 21 patients (57%) with IOCG positive for stones underwent successful laparoscopic clearance of the common duct, and did not require postop. ERCP. No patients were converted to an open procedure for common bile duct exploration. Because postoperative ERCP was 100% successful in clearing the common duct, reoperation for retained common bile duct stones was not necessary. IOCG is an alternative procedure to ERCP for patients at risk with biochemical, radiological, or clinical evidence of choledocholithiasis. The incidence of CBDS in low-risk patients is 1.7%, a risk that does not warrant routine cholangiography. Preoperative ERCP is recommended in cases of cholangitis unresponsive to antibiotics, suspicion of carcinoma, and biliary pancreatitis unresponsive to supportive care. Although IOCG leads to a similar percentage of nontherapeutic studies as preoperative ERCP, it often allows for one procedure therapy.

Effects of interleukin-11 and epidermal growth factor on residual small intestine after experimental massive small bowel resection.

Interleukin 11 (IL-11) is a multifunctional cytokine derived from bone marrow, which has a trophic effect on small bowel epithelium. This study compares the effects of IL-11 with epidermal growth factor (EGF), a growth factor known to enhance small bowel adaptation. Forty Sprague-Dawley rats (90-100g) underwent an 85% mid-small bowel resection with primary anastomosis on day 0. Rats were divided into four treatment groups: controls (group I) received bovine serum albumin (BSA), group II received IL-11, 125 microg/kg subcutaneously (SC) twice daily, group III received EGF, 0,10 microg/g SC bid, and group IV received EGF and IL-11 in the above doses. Half of the animals (five per group) were killed on day 4 of therapy, and the rest on day 8. Animals were evaluated for weight, mucosal length, and bowel wall muscle thickness on days 4 and 8, and expression of proliferating cell nuclear antigen (PCNA) in intestinal crypt and smooth muscle cells on day 8. Body weight was similar at day 4 and 8. Mucosal thickness in groups 11 (IL-11) and IV (IL-11 and EGF) was significantly increased at day 4 and 8 compared with controls (group I) and EGF (group III, P<.001). Muscle thickness was significantly increased in the EGF and combined group IV compared with the BSA controls and IL-11 groups (P < .001). Thirty-two percent of the mucosal crypt cells in group I stained positive for PCNA, whereas 51%, 53%, and 60% stained positive in groups II (IL-11), III (EGF), and IV (IL-11 and EGF), respectively. In groups I and II, 2% and 1.7% of the myocytes stained positive for PCNA, whereas 11.2% and 5.2% in group III and IV. These data suggest that IL-11 has a trophic effect on small intestinal enterocytes, causing cell proliferation and increased mucosal thickness. EGF has a more generalized effect causing proliferation of both enterocytes and myocytes. IL-11, with or without EGF may be a useful adjunct in treatment of short bowel syndrome.

Gastrointestinal stromal tumors (GIST).

BACKGROUND/AIMS: Gastrointestinal stromal tumors (GIST) are the most frequent non-epithelial tumors of the alimentary tract. The interstitial cells of Cajal or more primitive progenitor mesenchymal cells are suggested as their cells of origin. GIST's occur throughout the gastrointestinal tract but are generally located in the stomach and the intestine. About 70% of GIST's are immunohistochemically positive for CD34 and more than 90% for c-kit protein (CD117). About two thirds of GIST's are malignant. The tumor size, mitotic rate, cellularity and nuclear pleomorphism are the most important parameters characterizing the biological behavior of tumors. The diagnostic procedures are similar to those of other gastrointestinal neoplasms but only a half of the patients will have correct preoperative histological diagnosis. GIST's can be cured only by surgery. The procedure of choice, if possible, is resection without extended lymphadenectomy. Radiation and chemotherapy are generally ineffective. METHODOLOGY: 22 patients were operated on for GISTs in our department between 1996 and 2003. RESULTS: All but one proved to be benign. The patients were all asymptomatic after the operation except the malignant case. In his case an irresectable local recurrence developed later. CONCLUSIONS: GIST is a rare neoplasm of the GI tract. The only possibility for treatment of GISTs is surgical removal.

Role of nitric oxide, cAMP and cGMP in the radiation induced changes of tight junctions in Madin-Darby canine kidney cells.

Radiation induced inflammatory response is thought to be the consequence of acute and chronic oxidative stress, as well as the increased production of various intercellular mediators. Nitric oxide (NO) originated reactive nitrogen species, cGMP and cAMP are well known regulatory factors of the structure and functions of cell contacts. These data raise the possibility that they may play a role in the radiation induced alterations of tight junctions (TJs) and consequently in the radiation injury of surface tissues. Using immunohistochemical methods on confluent cultures of Madin-Darby canine kidney (MDCK) cells, our goal was to clarify the possible role of NO and its relationship with the cGMP and cAMP second messenger systems in the development of the radiation induced alterations of TJs. We found that increased levels of cAMP and/or inhibition of nitrogen oxide synthase (NOS) activity both tend to strengthen TJ associated cell-to-cell contacts in unirradiated control cells. In contrast increased level of cGMP and/or increased expression of NO-sythase, caused the and irregular staining of TJal complexes, which is commonly observed in irridated cells. Our experiments also indicated the protective role of the experimentally increased cAMP level and of NOS inhibitors against the radiation induced TJ changes. All these results suggest the key role of NO in the early radiation response of TJs.

Biological responses of tight junction to ionizing radiation and electromagnetic field expostion.

The tight junctions form and regulate the paracellular barrier in the intercellular spaces between epithelial and endothelial cells. They play important roles in the cellular and pathological processes, which follow exposure to radiation. Therefore, analysis of their changes upon different kind of irradiation may help to understand the basic events governing their function and give important information for the radiobiological research and clinical practice as well. The immunohistochemical data on the distribution of occludin presented here demonstrate the breakdown of tight junctions in Madin Darby kidney cells exposed to ionizing irradiation and show, on the other hand that magnetic field exposures upon 100 microT leave the occludin staining pattern intact.

Predictive factors for response to neoadjuvant therapy in patients with oesophageal cancer.

BACKGROUND: Preoperative radio-chemotherapy (RCX) was introduced to improve the outcome of patients with oesophageal cancer (EC), but conflicting results have been released. Some 20-30% of patients show a complete pathological response, however, the perioperative morbidity and mortality is increased. To search for factors indicating response prior to the onset of RCX we investigated the proliferative activity (MIB-1), the expression of vascular endothelial growth factor (VEGF), and the capillary density (CD34) in samples of EC obtained by endoscopy prior to the start of the treatment. METHODS: Forty-six (MIB-1) and 21 (VEGF, CD34) tissue specimens of ECs were available from 56 patients undergoing pretherapeutic endoscopy, RCX and surgery. Perioperative morbidity was divided into surgery and non-surgery related morbidity. MIB-1, VEGF and CD34 expression were investigated immunohistochemically. Multivariate analysis was carried out to prove independence of investigated variables. RESULTS: Postoperative morbidity was noticed in 54 of 56 operated patients. Eight of 56 patients who received RCX died in hospital. Survival was significantly different between the group of complete responders (n=14) and non-responders (n=23; P=0.0026). None of the investigated tumour samples from patients with a complete response (CR) had a proliferation index of less than 45. Tumour samples from patients with a CR showed a VEGF expression of 10.7 compared with 36.58 of tumours with no response (P=0.035). CD34 expression showed a correlation with VEGF expression. The relation of mean indices of VEGF expression and proliferative activity in tumours from patients with complete, partial or no response was 10.7:58.8, 18.3:53.8 and 36.6:43.5, respectively. CONCLUSIONS: According to these results, it may be expected that tumours with a VEGF/MIB-1 ratio of 1:6 or less prior to RCX will respond to this therapy.

[Gastrointestinal stromal tumors in our practice]. / Gasztrointesztinális stromális tumorok (GIST) elófordulása klinikánk anyagában.

The classification of tumours originating from the wall of gastrointestinal organs changed dramatically since of electronmicroscopy and immunohystochemistry were introduced. Previously these tumours were classified as leiomyomas, leiomyosarcomas or schwannomas. With the new methods these disorders can be described in more details and unified, and so the change to provide correct prognosis improved. Still, there are some unanswered questions remaining for the pathologists. In our material in the past 5 year we treated 9 patients because of GIST. Most of them were found in the stomach (6), one developed in the oesophagus, one in the small bowel and another one in the rectum. With describe our patients and look at the related articles literature about this important diseases. Though the incidence is under 1% of patients operated on because of gastrointestinal diseases, we would like to share our experiences in treatment.

Biomonitoring of human genotoxicity induced by complex occupational exposures.

Sensitivity, specificity and correlations among several biomarkers for monitoring occupational exposure to complex mixtures of genotoxic agents were assessed in occupational environments in Hungarian study populations. The studies have been focused on DNA adduct formation, urinary metabolites, mutations and micronuclei induced by exposures to complex organic mixtures. In two Hungarian aluminium plants, increased DNA adduct and 1-hydroxypyrene (1-OH-PY) levels were observed in workers as compared to controls. However, no association between the biomarker levels was evident on an individual basis. In Hungarian garage mechanics, DNA adduct determinations did not show increased genotoxic exposure as compared to the controls. However, ambient air measurements, significantly enhanced 1-OH-PY levels, and slightly enhanced frequency of micronuclei indicated increased polycyclic aromatic hydrocarbon (PAH) exposure in the garages, as compared to the general environment. In a Hungarian vulcanizing plant, DNA adduct determinations and 1-OH-PY did not show significantly elevated exposure levels as compared to controls. The glycophorin A (GPA) somatic mutation assay was also negative for this occupational exposure. The results support previous observations of a lack of correlation between DNA adducts detectable by 32P-postlabelling and those measured by the PAH-DNA immunoassay in the same DNA sample. These studies also demonstrate a lack of close correlation between levels of DNA adducts and urinary 1-OH-PY in the same individual.

X-irradiation-induced changes of the prelysosomal and lysosomal compartments and proteolysis in HT-29 cells.

As a consequence of external and internal ionizing radiation, lysosome-like bodies have been observed to increase both in size and number in some cell types. We investigated this process by morphological methods (electron microscopy, cationized ferritin uptake, acid phosphatase histochemistry, morphometry) in cultured HT-29 cells. In parallel with these studies, we measured the rate of protein degradation on the basis of 14C-valine release from prelabeled cellular proteins. We found that at 2 and 4 Gy doses of X-irradiation the volume of the vacuolar (probably lysosomal) compartment increased without detectable changes of acid phosphatase activity. A 2 Gy irradiation dose did not change protein degradation rate. However, 4 Gy caused a significant inhibition of 14C-valine release from prelabeled proteins. Our results indicate, that the radiation induced expansion of the lysosomal compartment is not necessarily accompanied by increased lytic activity of HT-29 cells.

X-irradiation-induced disorganization of cytoskeletal filaments and cell contacts in HT29 cells.

Organization of cytoskeleton and cell contacts were studied by immunochemistry and electron microscopy in confluent HT29 cultured cells following exposure to 0.5 and 1.0 Gy doses of X-ray. Microtubules were resistant to irradiation, whereas, the actin and intermediate filaments disrupted rapidly following the treatment and their components appeared as clumps of actin and cytokeratin aggregates in the cytoplasm as demonstrated by immunochemistry. Loss of cell contacts and decrease in the number of desmosomes was also characteristic of irradiated cells. Electron microscopy revealed intact desmosomes in control cells and abnormal desmosomes in the irradiated samples characterized by the absence of tonofilaments. The perinuclear filament network and cortical filaments were well detectable by electron microscopy. Under the effect of irradiation, the perinuclear filaments almost disappeared and, at the same time, small bundles of filaments were formed irregularly in the cytoplasm associated with amorphous material.

ISCOM of BHV-1 envelope glycoproteins protected calves against both disease and infection.

A subunit vaccine in the form of immunostimulating complex (iscom) was prepared to contain the envelope glycoproteins of bovine herpesvirus type 1 (BHV-1). This iscom preparation was tested in a vaccination experiment on 4-month-old calves seronegative to BHV-1. In this experiment, four groups with three animals per group were used. Two groups were vaccinated with the iscom preparation twice, four weeks apart, one group with 50 micrograms and the other with 100 micrograms per calf. The third group received a commercial inactivated whole-virus vaccine applying the same vaccination program. The fourth group served as control. Two weeks after the second vaccination, all the animals were challenge-infected intranasally with a virulent BHV-1 strain and four days later with a virulent Pasteurella multocida--this in order to mimic hard field conditions. When exposed to challenge infection, all the animals vaccinated with the iscom were fully protected, i.e., no virus could be recovered from their nasal secretions and no clinical symptoms were recorded. In contrast, the animals vaccinated with the commercial vaccine, responded to challenge with moderate fever and loss of appetite, and virus was isolated from the nasal secretions. The animals in the control group developed severe clinical symptoms. In the sera of iscom-vaccinated animals, the virus neutralization titers reached levels of 1/3500 or higher.