Ovarian carcinoma of low malignant potential treated at the 1(st) Department of Obstetrics and Gynecology Semmelweis University Faculty of Medicine,between 1990 and 2000

The authors analyzed the epidemiologic and histological characteristics and the management of ovarian carcinoma of low malignant potential (LMP) at a university hospital between 1990 and 2000. The authors carried out a retrospective study reviewing hospital charts. Based on the records experience with 29 such tumors is peresented. Of these 20 (74%) were of the serous variety, 7 (26%) were mucinous. LMP tumors accounted for 16% of proliferating epithelial ovarian tumors. They occured at a mean age of 45 years. The LMP tumors were bilateral in 12% of the cases. The majority of patients (87%) with LMP tumors presented with early stage disease. Tumor markers such as CA-125 were not always elevated as in invasive ovarian carcinoma. Laboratory investigations have not demonstrated that these tumors represent an intermediate step between benign ovarian tumors and carcinoma. The recommended therapy is surgical, consisting of total abdominal hysterectomy, bilateral salpingo-oophorectomy, peritoneal washings, and tumor debulking. Conservative surgery consisting of unilateral salpingo-oophorectomy is considered to be an appropriate treatment for young women with early stage LMP ovarian tumors who wish to retain their fertility potential. 50 percent of women who underwent conservative surgery subsequently conceived in this study. There were no recurrences in the study group, so the authors conclude that the long term outcome of LMP tumors is extremely favorable.     

Regulation of T-cell death-associated gene 51 (TDAG51) expression in human T-cells

T-cell death-associated gene 51 (TDAG51) has been described to regulate T-cell receptor/CD3-dependent induction of CD95/Fas and subsequent activation-induced cell death (AICD) in a murine T-cell hybridoma. Using well-defined pharmacological inhibitors, we investigated the regulation of TDAG51 expression in human T-cells and the correlation with cell death. TDAG51 was induced in resting T-cells, lymphoid cell lines and AICD-susceptible as well as AICD-resistant T-cell clones, and induction was inhibited by MAP-kinase inhibitors and PKC inhibitor G?6983. No correlation between the effects of inhibitors on TDAG51 expression and cell death was observed. The constitutive TDAG51 expression in five pancreatic carcinoma cell lines was reduced by MAP-kinase inhibitors but not by G?6983. Furthermore, the inducible overexpression of TDAG51 in TetOn Jurkat cells did not modulate cellular proliferation, phorbolester/ionomycin-induced growth arrest, or the expression of various cell surface molecules. Our results indicate that the expression of TDAG51 in human T-cells does not correlate with AICD.     

Soi3p/Rav1p functions at the early endosome to regulate endocytic trafficking to the vacuole and localization of trans-Golgi network transmembrane proteins

SOI3 was identified by a mutation, soi3-1, that suppressed a mutant trans-Golgi network (TGN) localization signal in the Kex2p cytosolic tail. SOI3, identical to RAV1, encodes a protein important for regulated assembly of vacuolar ATPase. Here, we show that Soi3/Rav1p is required for transport between the early endosome and the late endosome/prevacuolar compartment (PVC). By electron microscopy, soi3-1 mutants massively accumulated structures that resembled early endosomes. soi3Delta mutants exhibited a kinetic delay in transfer of the endocytic tracer dye FM4-64, from the 14 degrees C endocytic intermediate to the vacuole. The soi3Delta mutation delayed vacuolar degradation but not internalization of the a-factor receptor Ste3p. By density gradient fractionation, Soi3/Rav1p associated as a peripheral protein with membranes of a density characteristic of early endosomes. The soi3 null mutation markedly reduced the rate of Kex2p transport from the TGN to the PVC but had no effect on vacuolar protein sorting or cycling of Vps10p. These results suggest that assembly of vacuolar ATPase at the early endosome is required for transport of both Ste3p and Kex2p from the early endosome to the PVC and support a model in which cycling through the early endosome is part of the normal itinerary of Kex2p and other TGN-resident proteins.     

The Production of Reactive Oxygen Species in Intact Isolated Nerve Terminals Is Independent of the Mitochondrial Membrane Potential

Dependence on mitochondrial membrane potential (m) of hydrogen peroxide formation of in situ mitochondria in response to inhibition of complex I or III was studied in synaptosomes. Blockage of electron flow through complex I by rotenone or that through complex III by antimycin resulted in an increase in the rate of H₂O₂ generation as measured with the Amplex red assay. Membrane potential of mitochondria was dissipated by either FCCP (250nM) or DNP (50mM) and then the rate of H₂O₂ production was followed. Neither of the uncouplers had a significant effect on the rate of H₂O₂ production induced by rotenone or antimycin. Inhibition of the F₀F₁-ATPase by oligomycin, which also eliminates m in the presence of rotenone and antimycin, respectively, was also without effect on the ROS formation induced by rotenone and only slightly reduced the antimycin-induced H₂O₂ production. These results indicate that ROS generation of in situ mitochondria in nerve terminals in response to inhibition of complex I or complex III is independent of m. In addition, we detected a significant antimycin-induced H₂O₂ production when the flow of electrons through complex I was inhibited by rotenone, indicating that the respiratory chain of in situ mitochondria in synaptosomes has a substantial electron influx distal from the rotenone site, which could contribute to ROS generation when the complex III is inhibited.     

Differential modulation of the human liver conjugate transporters MRP2 and MRP3 by bile acids and organic anions

The multidrug resistance proteins MRP2 (ABCC2) and MRP3 (ABCC3) are key primary active transporters involved in anionic conjugate and drug extrusion from the human liver. The major physiological role of MRP2 is to transport conjugated metabolites into the bile canaliculus, whereas MRP3 is localized in the basolateral membrane of the hepatocytes and transports similar metabolites back to the bloodstream. Both proteins were shown to interact with a large variety of transported substrates, and earlier studies suggested that MRPs may work as co-transporters for different molecules. In the present study we expressed the human MRP2 and MRP3 proteins in insect cells and examined their transport and ATPase characteristics in isolated, inside-out membrane vesicles. We found that the primary active transport of estradiol-17-beta-d-glucuronide (E217betaG), a major product of human steroid metabolism, was differently modulated by bile acids and organic anions in the case of human MRP2 and MRP3. Active E217betaG transport by MRP2 was significantly stimulated by the organic anions indomethacin, furosemide, and probenecid and by several conjugated bile acids. In contrast, all of these agents inhibited E217betaG transport by MRP3. We found that in the case of MRP2, ATP-dependent vesicular bile acid transport was increased by E217betaG, and the results indicated an allosteric cross-stimulation, probably a co-transport of bile acids and glucuronate conjugates through this protein. There was no such stimulation of bile acid transport by MRP3. In conclusion, the different transport modulation of MRPs by bile acids and anionic drugs could play a major role in regulating physiological and pathological metabolite fluxes in the human liver.     

Current treatment of melanoma metastases of the brain

The appearance of brain metastases in patients with malignant melanoma predicts poor prognosis. During the last ten years important progress has been made in the treatment of brain metastases providing longer survival and better quality of life for these patients. In this review article the different treatment modalities, surgery, radiosurgery, radiation therapy and chemotherapy are described and the results published in the literature are briefly presented. Emphasis is made to show the effectiveness of a multimodality approach of this group of patients resulting in a better clinical outcome.     

Hexose phosphorylation and the putative calcium channel component Mid1p are required for the hexose-induced transient elevation of cytosolic calcium response in Saccharomyces cerevisiae

Saccharomyces cerevisiae responds to environ-mental stimuli such as an exposure to pheromone or to hexoses after carbon source limitation with a transient elevation of cytosolic calcium (TECC) response. In this study, we examined whether hexose transport and phosphorylation are necessary for the TECC response. We found that a mutant strain lacking most of the known hexose transporters was unable to carry out the TECC response when exposed to glucose. A mutant strain that lacked the ability to phosphorylate glucose was unable to respond to glucose addition, but displayed a normal TECC response after the addition of galactose. These results indicate that hexose uptake and phosphorylation are required to trigger the hexose-induced TECC response. We also found that the TECC response was significantly smaller than normal when the level of environmental calcium was reduced, and was abolished in a mid1 mutant that lacked a subunit of the high-affinity calcium channel of the yeast plasma membrane. These results indicate that most or all of the TECC response is mediated by an influx of calcium from the extracellular space. Our results indicate that this transient increase in plasma membrane calcium permeability may be linked to the accumulation of Glc-1-P (or a related glucose metabolite) in yeast.     

Improved growth of cultured brain microvascular endothelial cells on glass coated with a biological matrix

An improved method for culturing primary rat brain capillary endothelial cells on glass has been developed, using a corneal extracellular matrix coat. Since the collagen-coated plastic attachment surface conventionally used for primary cultures of brain microvascular endothelium gives a high level of background fluorescence in microfluorimetric studies, an alternative attachment surface was tested involving no plastic element. Five substrata combinations were examined and a new combination of glass and corneal endothelial extracellular matrix coat was found to provide excellent cell adhesion, culture growth and purity. Other established substrata combinations tested for comparison, either involved plastic, or used glass with collagen or carbodiimide and collagen coating but the last two gave poor endothelial cell adhesion and growth. Our method using this new attachment surface combination results in stable and pure endothelial cultures, as verified by immunocytochemistry, which are suitable for fluorimetric investigations.     

A Multistep High-Content Screening Approach to Identify Novel Functionally Relevant Target Genes in Pancreatic Cancer

In order to foster the systematic identification of novel genes with important functional roles in pancreatic cancer, we have devised a multi-stage screening strategy to provide a rational basis for the selection of highly relevant novel candidate genes based on the results of functional high-content analyses. The workflow comprised three consecutive stages: 1) serial gene expression profiling analyses of primary human pancreatic tissues as well as a number of in vivo and in vitro models of tumor-relevant characteristics in order to identify genes with conspicuous expression patterns; 2) use of ‘reverse transfection array’ technology for large-scale parallelized functional analyses of potential candidate genes in cell-based assays; and 3) selection of individual candidate genes for further in-depth examination of their cellular roles. A total of 14 genes, among them 8 from “druggable” gene families, were classified as high priority candidates for individual functional characterization. As an example to demonstrate the validity of the approach, comprehensive functional data on candidate gene ADRBK1/GRK2, which has previously not been implicated in pancreatic cancer, is presented.     

Relationship between osmotic stress-induced abscisic acid accumulation,biomass production and plant growth in drought-tolerant and -sensitive wheat cultivars

The effects of increasing osmotic stress induced by 100–400 mOsm (−0.976 MPa) polyethylene glycol (PEG 6000) were investigated in a drought-tolerant (Triticum aestivum L. cv. Mv Emese) and drought-sensitive (cv. GK élet) wheat cultivar at the three-leaf stage. During osmotic stress, the decline of the water potential (ψ _w) was more significant in the leaves, while the abscisic acid (ABA) levels of the roots increased earlier and remained higher in the sensitive than in the tolerant variety. There was an increasing gradient of ABA content toward the youngest leaves in the drought-sensitive GK élet, while more ABA accumulated in the fully developed, older leaves of the tolerant cultivar Mv Emese. In accordance with the rapid and significant accumulation of ABA, the stomatal conductance decreased earlier in the tolerant cultivar. The effect of water stress on the PSII photochemistry was pronounced only 1 week after the exposure to PEG, as indicated by the earlier decrease of the net CO₂ fixation, the effective quantum yield (Φ_PSII) and the photochemical quenching (q _P) in light-adapted samples of the tolerant variety in 400 mOsm PEG 6000. The stress treatment caused more significant reductions in these parameters toward the end of the experiment in the sensitive cultivar. In spite of small differences in the photosynthetic characteristics, the net biomass production was not significantly altered by this osmotic stress. The accumulation of ABA controlled the distribution of the biomass between the shoot and root systems under osmotic stress, and contributed to the development of stronger and deeper roots in the drought-sensitive cultivar GK élet. However, the root elongation did not correlate with the drought sensitivity of these cultivars on the basis of crop yield.