Eniko Németh

Publications of Eniko Németh

• Na+/Ca2+ exchanger inhibitors modify the accumulation of tumor-diagnostic PET tracers in cancer cells.

  Authors: Teréz Márián, Judit Szabó-Péli, Eniko Németh, Lajos Trón, Elza Friedlander, Anna Szabó, László Balkay, Gábor Veress, Zoltán Krasznai

  European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences. 02/2007; 30(1):56-63.

  AIM: To establish the effects of Na(+)/Ca(2+) exchanger (NCX) blockers on 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)FDG) and (11)C-choline accumulation in different cancer cells. METHODS: The tumorAIM: To establish the effects of Na(+)/Ca(2+) exchanger (NCX) blockers on 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)FDG) and (11)C-choline accumulation in different cancer cells. METHODS: The tumor cells were incubated with NCX inhibitors, and the uptakes of (18)FDG and (11)C-choline were measured. Flow cytometric measurements of intracellular Ca(2+) and Na(+) concentrations were carried out. The presence of the NCX antigen in the cancer cells was proved by Western blotting, flow cytometry and confocal laser scanning microscopy. RESULTS: The NCX is expressed at a noteworthy level in the cytosol and on the cytoplasmic membrane of the examined cells. Incubation of the cells with three chemically unrelated NCX blockers (bepridil, KB-R7943 or 3',4'-dichlorobenzamil hydrochloride) resulted in an increase in the intracellular Ca(2+) concentration, with a simultaneous decrease in the intracellular Na(+) concentration. The treatment with the NCX inhibitors increased the energy consumption of the tumor cells by 50-100%. Thapsigargin abolished the NCX-induced (18)FDG accumulation in the cells. The NCX blockers applied decreased the (11)C-choline accumulation of all the investigated cancer cells by 60-80% relative to the control. CONCLUSION: A possible masking effect of NCX medication must be taken into consideration during the diagnostic interpretation of PET scans.

• Paclitaxel modifies the accumulation of tumor-diagnostic tracers in different ways in P-glycoprotein-positive and negative cancer cells.

  Authors: Zoárd Tibor Krasznai, Judit Péli-Szabó, Eniko Németh, László Balkay, Gábor Szabó, Katalin Goda, László Galuska, Lajos Trón, Tamás Major, Zoltán Hernádi

  European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences. 07/2006; 28(3):249-56.

  AIM: To study how paclitaxel treatment modifies the accumulation of tumor-diagnostic radiotracers in P-glycoprotein (P-gp) positive and negative cancer cells. METHODS: The accumulations of differentAIM: To study how paclitaxel treatment modifies the accumulation of tumor-diagnostic radiotracers in P-glycoprotein (P-gp) positive and negative cancer cells. METHODS: The accumulations of different P-gp substrates, including rhodamine 123, daunorubicin and [(99m)Tc]hexakis-2-methoxybutyl isonitrile ((99m)Tc-MIBI), were measured in P-gp-positive (A2780AD) and P-gp-negative human ovarian carcinoma cells (A2780) and JY human lymphoid B cells. The uptakes of the tumor-diagnostic tracers (11)C-choline and 2-[(18)F]fluoro-2-deoxy-d-glucose ((18)FDG) were measured in the same cell lines. The P-gp expression and function were demonstrated by flow-cytometry. RESULTS: The (18)FDG measurements revealed that the glucose metabolic rate was significantly higher (p<0.01) in the P-gp-positive A2780AD cells than in the P-gp-negative cells. Paclitaxel (1-70microM) increased the (18)FDG uptake (up to 200%) of both P-gp-positive and P-gp-negative cells, whereas it did not modulate their (11)C-choline uptake. Paclitaxel reinstated the (99m)Tc-MIBI accumulation of the A2780AD cells (to 1500% of the control) in a concentration-dependent manner, while it increased the uptake of the P-gp-negative cells to a lesser extent (to a maximum of 200% of the control). CONCLUSION: Paclitaxel modifies the uptake of tumor-diagnostic tracers in both P-gp-dependent and independent manners. Interpretation of the multifactorial effects of paclitaxel may promote a correct in vivo diagnosis of P-gp-positive and P-gp-negative tumors.

• [The role of positron emission tomography (PET) in the detection of local recurrence and metastases of colorectal cancer]

  Authors: Zsolt Kanyári, László Orosz, Balázs Juhász, Miklós Tanyi, Eniko Németh, Lajos Trón, Lászlo Damjanovich, Géza Lukács, Beáta Kálvin

  Magyar sebészet. 07/2005; 58(3):179-83.

  We presented here the results of PET imaging of 12 patients, previously operated on for colorectal cancer and followed at the 1st Department of Surgery, University of Debrecen. The tests were carriedWe presented here the results of PET imaging of 12 patients, previously operated on for colorectal cancer and followed at the 1st Department of Surgery, University of Debrecen. The tests were carried out using 0.15 mCi/kg FDG injections. Whole body imaging was performed in eleven patients. The indication for PET was elevated tumor marker levels in three patients, although CT scan was negative. The PET scan showed lymph node, hepatic and disseminated lymph node metastases with liver involvement in these patients. Suspicious lesions were found on CT scan in the pelvis of four patients. Local recurrence was identified in three of them, PET was negative in the fourth case. Bone scan suggested rib metastasis in one patient, which was not supported at PET investigation. In one patient, the malignant nature of large retroperitoneal lymph nodes could not be determined by CT. PET imaging proved that they were malignant and detected a previously unknown pulmonary metastasis at the same time. In one patient both pulmonary and liver metastases were seen on CT, whereas PET confirmed only the latter. Similarly, CT failed to identify liver metastasis detected at ultrasound, while PET proved it. Finally, a pulmonary metastasis detected on X-ray, could be confirmed by PET only. Based on our experience, we recommend PET-scanning with FDG when conventional imaging is equivocal and/or elevated tumor marker levels are present during follow-up. FDG-PET is important in the detection of local recurrence and metastases as well. It is advisable to use PET more often in the evaluation of patients with recurrent colorectal cancer in order to diagnose recurrences in earlier stages, which helps to identify patients who will benefit from surgery.