Neurogenic tumors of the digestive tract: report of two cases.

We report two female patients with neurogenic tumors of the digestive tract. In the first patient, the tumor of 10 cm diameter originated in the stomach and at preoperative CT imitated a peripancreatic cyst. In the second patient, the tumor of 6 cm diameter originated in the duodenum. Despite large size, the tumors were clinically indolent and escaped detection at routine endoscopic evaluation. In both cases the neoplasm was removed and postoperative histopathology combined with immunohistochemistry was consistent with diagnosis of digestive Schwannoma.

[Vascular changes of colonic mucosa as a cause of lower gastrointestinal bleeding in patients with liver cirrhosis]. / Zmiany naczyniowe blony sluzowej jelita grubego jako przyczyna krwawienia z dolnego odcinka przewodu pokarmowego u chorego z marskoscia watroby.

Gastrointestinal bleeding is the common complication of the portal hypertension. Endoscopy is the most accessible diagnostic technique, but the investigation is often limited to the endoscopy of upper gastrointestinal tract. Colonoscopy in the case of bleeding from the colon is often limited by the possibility of good bowel preparation to that procedure. However diagnostic colonoscopy in these cases increases chances for correct diagnosis and application of adequate treatment. Increasing number of gastrointestinal bleeding cases in the last decade causes the necessity of focusing on this problem.

Acute cholestatic hepatitis associated with pravastatin.

A 57-yr-old man presented with clinical and laboratory signs of acute cholestatic hepatitis. Symptoms had appeared 7 wk after he was started on pravastatin 20 mg/day for hypercholesterolemia. A full evaluation including ultrasound, computed tomography, endoscopic cholangiography, and liver biopsy confirmed the diagnosis of intrahepatic nonobstructive jaundice. The liver function abnormalities normalized 7 wk after cessation of therapy. Pravastatin should be considered as a potential cause of cholestatic hepatitis with favorable clinical outcome after drug withdrawal.

GST-Induced dimerization of DNA-binding domains alters characteristics of their interaction with DNA.

The steroid hormone 20-hydroxyecdysone (20E) plays a key role in the induction and modulation of morphogenetic events throughout Drosophila melanogaster development. Two members of the nuclear receptor superfamily, the product of the EcR (EcR) and of the ultraspiracle genes (Usp), heterodimerize to form its functional receptor. To study the receptor-DNA interaction, critical for regulating 20E-dependent gene expression, it is necessary to produce large quantities of EcR and Usp DNA-binding domains. Toward this end DNA-binding domains of EcR and Usp (EcRDBD and UspDBD, respectively) were cloned and expressed in Escherichia coli as fusion proteins with glutathione S-transferase (GST). However, the results of DNA-binding studies obtained with purified GST-DBDs were found to be questionable because the fused proteins oligomerized in solution due to the presence of GST. Therefore DBDs were released from GST-chimeric proteins by thrombin cleavage and then purified by glutathione-Sepharose 4B chromatography and by gel filtration on Superdex 75 HR. The gel mobility-shift experiments showed that UspDBD exhibited higher affinity than EcRDBD toward a 20-hydroxyecdysone response element from the Drosophila hsp 27 gene (hsp 27pal). Furthermore, formation of the heterodimeric EcRDBD-UspDBD complex was observed to be synergistic when equimolar mixture of both DBDs was incubated with hsp 27pal. Surprisingly, GST-EcRDBD bound hsp 27pal with higher affinity than GST-UspDBD. This difference was accompanied by the impaired ability of the GST-DBDs to interact synergistically with hsp 27pal. This is the first report on expression and purification of the soluble DBDs of the functional ecdysteroid receptor with satisfying yields. Furthermore, our results add to the recent findings which indicate the need for caution in interpreting the activities of GST fusion proteins.

Expression and purification of 6xHis-tagged DNA binding domains of functional ecdysteroid receptor from drosophila melanogaster.

Two members of the nuclear receptor superfamily, EcR and Ultraspiracle (Usp) heterodimerize to form a functional receptor for 20-hydroxyecdysone-the key ecdysteroid controlling induction and modulation of morphogenetic events through Drosophila development. In order to study aspects of receptor function and ultimately the structural basis of the ecdysteroid receptor-DNA interaction, it is necessary to produce large quantities of purified EcR and Usp DNA-binding domains. Toward this end, we have expressed the EcR DNA-binding domain and the Usp DNA-binding domain as proteins with an affinity tag consisting of six histidine residues (6xHis-EcRDBD and 6xHis-UspDBD, respectively) using the expression vector pQE-30. Under optimal conditions, elaborated in this study, bacteria can express the recombinant 6xHis-EcRDBD to the levels of 11% of total soluble proteins and the 6xHis-UspDBD to the levels of 16%. Both proteins were purified to homogeneity from the soluble protein fraction using combination of ammonium sulphate fractionation and affinity chromatography on Ni-NTA agarose. The gel mobility shift experiments demonstrated that the purified 6xHis-EcRDBD and the 6xHis-UspDBD interact specifically with an 20-hydroxyecdysone response element from the promoter region of the hsp 27 Drosophila gene.