Cylindrospermopsin occurrence in two German lakes and preliminary assessment of toxicity and toxin production of Cylindrospermopsis raciborskii (Cyanobacteria) isolates.

Cylindrospermopsis raciborskii, a freshwater cyanobacterium of tropical origin, is not only increasingly found in (sub) tropical water bodies, but also in temperate regions. Since this species may produce potent toxins such as cylindrospermopsin (CYN) and paralytic shellfish poisons, its massive occurrence in water bodies used as drinking water sources or for recreation is of major concern. The proliferation of C. raciborskii in German water bodies has been documented for the past decade. We investigated the occurrence of CYN in field populations and isolates of C. raciborskii from two lakes, and assessed the toxicity of culture isolates using the mouse bioassay, primary rat hepatocytes and human derived cell lines. We show for the first time the occurrence of CYN in German water bodies. None of seven isolates of C. raciborskii contained CYN, however, all isolates were toxic to primary rat hepatocytes, human hepatoblastoma (HEP-G2) and human colon adenocarcinoma (CACO-2) cells. Methanolic extracts were more toxic than aqueous extracts. Three isolates tested in the mouse bioassay were toxic at a concentration of 800 mg kg(-1) showing liver and spleen damage and inflammation of the intestine. These results give strong evidence that the German isolates of C. raciborskii contain currently not identified or unknown toxins.

RAMEDIS- rare metabolic diseases publishing tool for genotype-phenotype correlation.

To gain further knowledge about rare genetic diseases, a world wide method for data collection via the Internet has been established. This new approach will improve collecting valuable data from single case reports. RAMEDIS saves standardised patient data which will be usable for statistics, longitudinal examinations and co-operative studies in future time. Embedded in the scene of the German Human Genome Project, RAMEDIS directly will enable phenotype-genotype correlation's. Technically RAMEDIS is based on the Oracle database management system with some additional tools. Since November 2000 first case reports are committed online. Beside the better characterisation of clinical heterogeneity of rare diseases, there may be a great benefit for the treatment of these patients in whom prospective studies are otherwise expensive and difficult to perform. Quality of clinical diagnostic process and therapy will increase.

Knowledge acquisition, management and representation for the diagnostic support in human inborn errors of metabolism.

The very complex and specific knowledge about inborn errors of metabolism increases rapidly and is spread worldwide. Therefore an Internet platform for the acquisition of statistical knowledge (PATDB) and for the collection of the experience of experts (Metabolic diseases database) has been established. The success of diagnostic support highly depends on the way of knowledge representation. An information retrieval system for physicians will offer first insights about useful user interfaces and handling properties. Furthermore information fusion of biomedical systems to a Biomedical Workbench for the simulation of biochemical reactions is described.

Metabolic drug pointing and information processing.

Computer supported drug design is based on the biochemical information for the prediction of alternative bio-chemical pathways. Molecular information on genes, proteins, biochemical reactions, mutations, inborn errors and metabolic diseases are available via internet. Based on this information we developed an information retrieval and processing concept combining knowledge about metabolic diseases and biochemical effects.

The international validation study of the acute toxic class method (oral).

An alternative to the oral LD50 test, the acute toxic class (ATC) method (oral), was validated with 20 substances in an international collaborative study with nine laboratories in five countries. The ATC method is a stepwise procedure with the use of three animals per step. It has been designed with three fixed doses (25, 200 and 2000 mg/kg). In general, this testing is sufficient for allocation to the toxicity classes of the majority of the international classification systems currently in use. The selection of testing at additional fixed doses (5, 50 and 500 mg/kg) may be considered if further refinement is necessary or for specific allocation to those international classification systems with a cut-off value of 5 mg/kg. On average, two to four steps are necessary to complete a test. With the ATC method substances can be ranked in a similar or even better manner than with an LD50 test but it uses up to 90% fewer animals, the average being 70% fewer. This also results in substantially fewer moribund/dead animals. The ATC method is based on biometric evaluations that, together with the experimental results, demonstrate that this method is a sensitive and reliable alternative to the LD50 test.

The biometric evaluation of the acute-toxic-class method (oral).

The acute toxic class method (ATC method) is an alternative to the LD50 test, with the use of substantially fewer animals needed for the classification of substances. Like the classical LD50 test the biometry of the ATC method is based on the probit model. The biometric calculations of the ATC method were carried out not only for the classification categories of the European Union but also for the classification criteria of various countries and organizations, currently in use. It is demonstrated that in comparison with the LD50 test in general the same classification is obtained with the ATC method and with the use of substantially fewer animals. Substances with high slopes are likely to be allocated to the predicted toxicity class in comparison with substances having low slopes, with both the ATC method and the LD50 test. Substances are more likely to be allocated into a lower toxicity class with the LD50 test than with the ATC method.

A national validation study of the acute-toxic-class method--an alternative to the LD50 test.

In a national collaborative study an alternative to the classical LD50 test--the acute-toxic-class method--was validated. With this testing procedure mortality ranges are determined between defined dose levels that are used for classification and labelling in the European Community. The results were compared with LD50 data obtained from the literature which were categorized according to the defined dose levels. The results of this collaborative study have shown that the acute-toxic-class method allows allocation to the toxicity classes of very toxic, toxic, harmful and unclassified in the same manner as on the basis of the classical LD50 tests. The acute-toxic-class method uses fewer animals and subjects fewer animals to pain and distress than the LD50 test and yields the same information on toxic signs in the treated animals. Identical classifications were obtained by the six participating laboratories in 86% of the tests. This demonstrates that the acute-toxic-class method results in excellent reproducibility in comparison to the classical LD50 test and that this new method is a reliable alternative to the LD50 test.

Groove pancreatitis.

Groove pancreatitis is characterized by the formation of a scar plate between the head of the pancreas and the duodenum, and is by no means a rare entity. In our material comprising surgical specimens, it was found to be present in 19.5% of the cases. This form of pancreatitis is "special" only on account of the topography of the scar tissue. Scarring of the groove leads to complications that are also determined by the topography: disturbance of the motility of the duodenum, stenosis of the duodenum, and tubular stenosis of the common bile duct, which occasionally extends to obstructive jaundice. In the "pure" forms of groove pancreatitis the main pancreatic duct is not involved, and this fact has a certain significance in the differential diagnosis vis-à-vis carcinoma of the head of the pancreas, since signs of stenosis with no involvement of the rest of the pancreas are, in the first instance, suspicious for carcinoma and provide the indication for surgery. A knowledge of the existence of groove pancreatitis suggests a differential-diagnostic alternative. In terms of etiology, pathogenesis, and the pathological/anatomical picture, groove pancreatitis is "special" only on account of its topographic aspects.

Tissue reactions under piezoelectric shockwave application for the fragmentation of biliary calculi.

The tissue reactions that occurred during piezoelectric shockwaves for the fragmentation of biliary calculi were investigated in 10 surgically removed stone containing human gall bladders and in acute (six dogs) and chronic (six dogs) animal experiments. Before and after shockwave (500, 1500 or 3000) in the anaesthetised dogs, computed tomography (CT), magnetic imaging (MRI) and laboratory tests were done; treatment was carried out under continuous ultrasonographic control. Shockwave applications to the human gall bladders resulted in disintegration of the stones with no macroscopically or microscopically detectable tissue changes. In acute animal experiments, small haematomas were observed in all six animals at surfaces, but also inside the liver and gall bladder (max diameter 25 mm). Perforation or intra-abdominal or pleural bleeding did not occur. In chronic experiments, no macroscopic, and only slight microscopic residual lesions (haemosiderin deposits) were seen three weeks after shockwave. In almost all instances, the lesions were detected by CT, MRI, and ultrasonography, while laboratory tests were negative.

[Kaposi's sarcoma with pericardial tamponade in AIDS]. / Kaposi-Sarkom mit Herzbeuteltamponade bei AIDS.

In two males with AIDS, aged 26 and 39 years, who had disseminated Kaposi's sarcoma, massive pericardial effusion with tamponade (confirmed by echocardiography) developed in the final stages. Multiple pericardial taps, of up to two litres, of serous fluid yielded no malignant cells or pathogens cytologically or microbiologically. At autopsy the finding was of cytomegalovirus and cryptococcus septicaemia, respectively, and generalized Kaposi's sarcoma with infiltration of the heart along the great vessels and subepicardially along the coronary vessels. The pericardial sac was distended balloon-like with 800 ml sanguinous fluid (in both cases). Histological examination did not demonstrate cytomegalic inclusion bodies or fungal granulomas in cardiac tissue. The pericardial effusion was probably due to tumour spread in the lymph channels and along the vasa vasorum.

[Cholaemic placentosis--a contribution to metabolic disorders of the placenta]. / Cholämische Plazentose--Ein Beitrag zur Stoffwechselstörung der Plazenta.

The deposition of bile substances produces intracellular metabolic disorders in the organs so affected. Since severe cholaemia is rare in pregnancy, similar disorders of the placental cells have been not discussed up to now. We report on morphological observations in a placenta of a stillbirth in the middle of pregnancy. Bile substances are deposited in the syncytiotrophoblast and Hofbauer cells, pointing to the probable function of the Hofbauer cells as macrophages.