Cancer-ID: Toward Identification of Cancer by Tumor-Derived Extracellular Vesicles in Blood.

Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1 µm) in blood from cancer patients are associated with poor outcome, and changes in their number can be used to monitor therapy effectiveness. Whereas, small tumor-derived EVs (<1 µm) are likely to outnumber their larger counterparts, thereby offering better statistical significance, identification and quantification of small tdEVs are more challenging. In the blood of cancer patients, a subpopulation of EVs originate from tumor cells, but these EVs are outnumbered by non-EV particles and EVs from other origin. In the Dutch NWO Perspectief Cancer-ID program, we developed and evaluated detection and characterization techniques to distinguish EVs from non-EV particles and other EVs. Despite low signal amplitudes, we identified characteristics of these small tdEVs that may enable the enumeration of small tdEVs and extract relevant information. The insights obtained from Cancer-ID can help to explore the full potential of tdEVs in the clinic.

Intra-individual, randomised comparison of the MRI contrast agents gadobutrol versus gadoteridol in patients with primary and secondary brain tumours, evaluated in a blinded read.

OBJECTIVE: To prove that 1.0 M gadobutrol provides superior contrast enhancement and MRI image characteristics of primary and secondary brain tumours compared with 0.5 M gadoteridol, thereby providing superior diagnostic information. METHODS: Brain MRI was performed in two separate examinations in patients scheduled for neurosurgery. Independent injections of 1.0 M gadobutrol and 0.5 M gadoteridol at doses of 0.1 mmol Gd/kg body weight were administered per patient in randomised order. Evaluation was performed in an off-site blinded read. RESULTS: Fifty-one patients in the full analysis set (FAS) were eligible for efficacy analysis and 44 for the per-protocol analysis. For the primary efficacy variable "preference in contrast enhancement for one contrast agent or the other", the rate of "gadobutrol preferred" was estimated at 0.73 (95 % confidence interval 0.61; 0.83), showing significant superiority of gadobutrol over gadoteridol. Calculated lesion-to-brain contrast and the results of all qualitative secondary efficacy variables were also in favour of gadobutrol. Keeping a sufficient time delay after contrast application proved to be essential to get optimal image quality. CONCLUSION: Compared with 0.5 M gadoteridol, 1.0 M gadobutrol was proven to have significantly superior contrast enhancement characteristics in a routine MRI protocol of primary and secondary brain tumours.

Strains ofaspergillus versicolor tiraboschi synthesizing sterigmatocystin and the differentiation of mycotoxic risk dependent on their productivity in housing buildings.

In biomasses from 22 moulds isolated in housing buildings a Chromatographie HPLC UV/VIS analysis was carried out to assess the production of sterigmatocystin by fungal isolates. The results are discussed with respect to mycotoxic risk for people exposed to the presence ofAspergillus versicolor. This fungus is often present on building materials, but does not always produce the carcinogenic mycotoxin sterigmatocystin (ST). In this study, 19 (86%) of the 22 strains synthesized ST at detectable levels (>0.03 mg kg-1 biomass). Three of the strains (14%) were found to synthesize ST at levels exceeding 100 mg kg-1 of the air-dry mould biomass with laboratory medium. One strain proved to be highly productive and synthesized more than 500 mg kg-1 ST. Thus, it presented the highest mycotoxic danger for the dwellers of the buildings whereA. versicolor infested the walls. However, most strains are low producers of ST, with 12 of 22 isolates synthesizing less than 10 mg kg-1 biomass. Mycotoxigenic and highly productive strains that produced significant amounts of ST (>500 mg kg-1 biomass) were less frequently found, with approximately 5% of all isolates from buildings studied for ST production.

High-level secretion of hirudin by Hansenula polymorpha--authentic processing of three different preprohirudins.

A DNA sequence coding for a subtype of the hirudin variant HV1 was expressed in the methylotrophic yeast Hansenula polymorpha from a strongly inducible promoter element derived from a gene of the methanol metabolism pathway. For secretion, the coding sequence was fused to the KEX2 recognition site of three different prepro segments engineered from the MF alpha 1 gene of Saccharomyces cerevisiae, the glucoamylase (GAM1) gene of Schwanniomyces occidentalis and the gene for a crustacean hyperglycemic hormone from the shore crab Carcinus maenas. In all three cases, correct processing of the precursor molecule and efficient secretion of the mature protein were observed. In fermentations on a 10-1 scale of a transformant strain harbouring a MF alpha 1/hirudin-gene fusion yields in the range of grams per litre could be obtained. The majority of the secreted product was identified as the full-length 65-amino-acid hirudin. Only small amounts of a truncated 63-amino- acid product, frequently observed in S. cerevisiae-based expression systems, could be detected.

Growth inhibition of human gastrointestinal cancer cells by cyclosporin A.

We have studied the ability of cyclosporin A (CsA) to inhibit the growth of human AGS gastric and HT29 colon carcinoma cells in vitro. Using continuous drug exposure in growth assays of cultured tumour cells we found that CsA produced a dose-dependent growth inhibition in gastric and colon cancer cells with a half-maximal effect at 5 microM and 6 microM CsA respectively. The growth inhibition of CsA was reversible in AGS cells, when the tumour cells were incubated in normal growth medium following CsA treatment. Trypan blue dye exclusion in AGS cells indicated a cytostatic rather than a cytotoxic effect in the concentration range used. Coincubation of CsA-treated cells with 10-400 U/ml interleukin-2 (IL-2) could not abrogate this growth inhibition, suggesting an IL-2 independent mechanism of action. Flow-cytometric analysis did not reveal a phase arrest of the gastric cancer cells within the cell cycle. We conclude from our experiments that CsA cytostatically and reversibly inhibits the growth of human gastric cancer cells in a dose-dependent manner. In contrast to its mechanism of action in lymphocytes, this direct antiproliferative effect of CsA seems not to be mediated by an IL-2-dependent pathway or a cell-cycle-phase arrest of the tumour cells.

Vascularization of carcinomas of the esophagus and its correlation with tumor proliferation.

Vascularization and tumor cell proliferation were analyzed in 33 resected human squamous cell carcinomas of the esophagus using the endothelium-specific antibody BW 200 and the proliferation-associated antibody Ki-67. Vascular parameters (relative capillary volume, relative total vessel volume, vascular surface area, and vascular length) as well as the percentage of proliferating tumor cells (Ki-67 index) were evaluated on frozen sections by a morphometric method. Vascular parameters of the normal mucosa exceeded those of tumors significantly, by a factor of 1.4-2.3. The mean distance between tumor capillaries and the onset of necrosis was 92 +/- 34 microns. Global vascular density did not correlate with TNM stage, tumor diameter, or overall tumor proliferation (mean Ki-67 index, 35.1%; range, 14.2-64.1%). However, a significant negative correlation existed between the percentage of proliferating tumor cells per tumor cord and the intercapillary distance between capillaries located at the edges of these cords. This observation points to the fact that the esophageal cancers were composed of multiple tumor cords and that each of these cords possessed its own supply capillaries at the base of the cord. The sum of these "supply units" thus constitutes an esophageal cancer. The intercapillary distance may reflect the oxygenation status of tumor cells, which cannot be predicted on the basis of tumor staging or grading.

Antiproliferative effect of tyrosine kinase inhibitors in epidermal growth factor-stimulated growth of human gastric cancer cells.

AGS human gastric cancer cells were characterized to possess EGF receptors. Scatchard analysis revealed a half saturation constant of 0.6 nM and 9000 receptors per cell. Exogenously added EGF stimulated gastric cancer cell growth in a dose-dependent manner with a maximum effect of +38% at 10 nM EGF. Inhibition of the EGFR-associated tyrosine kinase by genistein and the tyrphostins RG-13022, RG-14620 and RG-50864 resulted in a dose-dependent growth inhibition with half maximal inhibition at 10 microM, 7 microM and 23 microM, respectively. EGF mediated growth stimulation was dose-dependently reversed by coincubation with genistein. At genistein concentrations exceeding 6 microM serum-stimulated growth of AGS cancer cells was also inhibited. We conclude that EGF is an important growth factor for AGS gastric cancer cells. Inhibition of the EGFR-associated tyrosine kinase seems to be an effective antiproliferative principle in EGFR-positive human gastric cancer cells.

Differential mode of action of high- and low-affinity CCK/gastrin receptor antagonists in growth inhibition of gastrin--responsive human gastric adenocarcinoma cells in vitro.

Exogenous gastrin exerted a trophic effect on the human gastric adenocarcinoma cell line AGS with a maximum stimulation at 100 pM. The CCK/gastrin receptor antagonists proglumide and loxiglumide dose-dependently inhibited spontaneous growth of AGS gastric cancer cells with half maximal inhibition at 8 mM and 200 microM, respectively. This growth inhibition could not be reversed by coincubation with gastrin. In control experiments with murine 3T3 fibroblasts gastrin had no growth-promoting effect. Proglumide and loxiglumide, however, exerted the same growth inhibition on 3T3 cells as they did on gastrin-responsive AGS tumor cells, suggesting a gastrin receptor independent mode of action. L 365, 260 had no effect on the spontaneous growth of AGS tumor cells, but abolished growth stimulation by exogenous gastrin in a dose-dependent manner. These results suggest that only the high-affinity gastrin receptor antagonist L 365, 260 acts by a specific, i.e. selective, reversible, and competitive mode of action. In contrast, the low affinity CCK/gastrin receptor antagonists proglumide and loxiglumide obviously have an irreversible and non-competitive mode of action with respect to growth inhibition of AGS gastric cancer cells, which is not mediated by gastrin receptors.

Protein kinase C and adenylate cyclase as targets for growth inhibition of human gastric cancer cells.

In the human gastric adenocarcinoma cell line AGS the effects of the protein-kinase-C-activating phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA), the protein kinase C inhibitor staurosporine, the adenylate-cyclase activating agent forskolin, and the permeable dibutyryl-adenosine 3',5'-monophosphate (Bt2cAMP) on the proliferation were assessed. Cell counting followed 5 days of incubation. Prolonged activation of protein kinase C by TPA, inhibition of protein kinase C by staurosporine, activation of adenylate cyclase by forskolin or a direct increase of the intracellular cAMP level all result in a dose-dependent growth inhibition of AGS gastric tumour cells. Half-maximal inhibition was achieved at 100 pM for TPA, 1 nM for staurosporine, 20 microM for forskolin, and 600 microM for Bt2cAMP. It is concluded that protein kinase C and adenylate cyclase play a fundamental role in the growth of AGS gastric cancer cells. Interference with these enzymes involved in the signal transduction of growth regulation in tumour cells may represent a target in the development of new antiproliferative principles.

Effect of calcium-modifying agents on the growth of human gastric carcinoma cells in vitro.

The antiproliferative effects of various calcium-modifying agents were investigated in human AGS gastric carcinoma cells in culture. Variation of the extracellular calcium concentration, achieved by addition of calcium to the growth medium or binding of calcium to the calcium-chelating agent EDTA, appeared to have little influence on growth of the tumor cells. In contrast, the calcium antagonist verapamil, the calcium ionophore A 23.187 and the calmodulin antagonist W 7, agents supposed to interfere with the regulation of the intracellular calcium concentration, all exerted marked growth inhibiting effects. Our results provide evidence for an important role of intracellular calcium-dependent mechanisms in growth regulation of the human gastric adenocarcinoma cell line AGS.

Heterologous protein production in yeast.

The exploitation of recombinant DNA technology to engineer expression systems for heterologous proteins represented a major task within the field of biotechnology during the last decade. Yeasts attracted the attention of molecular biologists because of properties most favourable for their use as hosts in heterologous protein production. Yeasts follow the general eukaryotic posttranslational modification pattern of expressed polypeptides, exhibit the ability to secrete heterologous proteins and benefit from an established fermentation technology. Aside from the baker's yeast Saccharomyces cerevisiae, an increasing number of alternative non-Saccharomyces yeast species are used as expression systems in basic research and for an industrial application. In the following review a selection from the different yeast systems is described and compared.

Crohn's disease: what about the pancreas?

Crohn's disease (CD) is now accepted as a systemic illness. The importance of extraintestinal manifestations is underlined by the fact that such "complications" can be more prominent and even more difficult to control than the intestinal disease itself. Lately, evidence for a more than accidental association of pancreatitis and exocrine pancreatic insufficiency with CD is growing. This might have a significant impact on the treatment of abdominal pain and diarrhea in CD, symptoms which have so far been attributed exclusively to the intestinal rather than the extraintestinal manifestations of the disease.

[Noncirrhotic liver fibrosis after chronic arsenic poisoning]. / Nicht-zirrhotische Leberfibrose nach chronischer Arsenintoxikation.

A 67-year-old woman with portal hypertension, splenomegaly without portal vein thrombosis, leucopenia and thrombocytopenia of splenic origin had repeated episodes of life-threatening haemorrhage from esophageal varices. Since childhood she had suffered from psoriasis and had been treated over a period of 15 years with Fowler's solution (in all about 25 g of arsenic trioxide). She had the characteristic skin lesions of arsenical poisoning-palmar hyperkeratoses and two basal cell carcinomas on the trunk. Histological examination of a wedge biopsy from the liver showed definite structural changes with fibrosis around the central veins and in the portal tracts. There was no evidence of cirrhotic alteration. The hepatocytes were normal by light microscopy and electron microscopy. This case of noncirrhotic hepatic fibrosis is considered to have been caused by chronic arsenical poisoning.

[Late initial manifestations of Crohn disease with atypical symptoms]. / Späte Erstmanifestation eines Morbus Crohn mit atypischen Symptomen.

The case of a 55-year-old patient with Crohn's disease and chronic intermittent diarrhea as well as progressive weight loss of 20 percent of his body weight is reported. The establishment of the diagnosis was difficult at the beginning, since characteristic symptoms were missing and radiological and endoscopical findings were normal. Loam-coloured glossy stools, repeated registration of a reduced chymotrypsin concentration of the stool and the response of the symptoms to a substitution of pancreatic enzymes were initially regarded as signs of an exocrine pancreas insufficiency. Not before multiple biopsies were taken from the macroscopically largely normal small and large intestine during persisting complaints, an extensive infiltration with Crohn's disease could be shown. This case report emphasizes the importance of taking multiple biopsies in etiologically unexplained chronic diarrhea even from macroscopic inconspicuous intestinal mucosa. Because of the rising incidence of Crohn's disease late onset is gaining increasing significance in the differential diagnosis of chronic diarrhea in the elderly patients.