Authors:Hajnalka Ábrahám, A. Losonczy, G. Czéh and Gy. Lázár
The effect of potassium channel blockers tetraethylammonium and 4-aminopyridine was examined on the elevated K+ concentration-induced microglial activation on rat hippocampal slice preparations. Microglial cells were detected by immunohistochemistry with a monoclonal antibody (OX 42) raised against a type 3 complement receptor. During activation the morphology of the microglial cells changes and the staining intensity increases. The degree of microglial activation was determined by measuring the integrated optical density of the cells. Tetraethylammonium and 4-aminopyridine failed to reduce the elevated K+ concentration-induced microglial activation. Both potassium channel blockers, when applied on the hippocampal slices without K+, caused significantly increased microglial activation as compared to the control slices. In order to check whether the functional alteration of the neuronal population induced by 4-aminopyridine caused the activation of the microglial cells, Schaffer collaterals were cut to block spreading of epileptiform hyperactivity of the CA3 pyramidal cells to the CA1 region. No significant differences were found in microglial activation between the CA3 and CA1 regions, indicating that the effect of 4-aminopyridine on microglial cells is independent of the epileptiform activity caused by the drug.
Authors:Bernadett Borda, Cs. Lengyel, T. Várkonyi, É. Kemény, A. Ottlakán, A. Kubik, Cs. Keresztes and Gy. Lázár
New-onset diabetes after transplantation (NODAT) is one of the frequent complications following kidney transplantation. Patients were randomized to receive cyclosporine A- or tacrolimus-based immunosuppression. Fasting and oral glucose tolerance tests were performed, and the patients were assigned to one of the following three groups based on the results: normal, impaired fasting glucose/impaired glucose tolerance (IFG/IGT), or NODAT. NODAT developed in 14% of patients receiving cyclosporine A-based immunosuppression and in 26% of patients taking tacrolimus (p = 0.0002). Albumin levels were similar, but uric acid level (p = 0.002) and the age of the recipient (p = 0.003) were significantly different comparing the diabetic and the normal groups. Evaluation of tissue samples revealed that acute cellular rejection (ACR) and interstitial fibrosis/tubular atrophy (IF/TA) were significantly different in the NODAT group. The pathological effect of new-onset diabetes after kidney transplantation can be detected in the morphology of the renal allograft earlier, before the development of any sign of functional impairment.