Browsing by Author "Bumbasirevic, V. (6603957757)"

Experimental autoimmune encephalomyelitis (EAE) is a well-recognized model for multiple sclerosis (MS) in humans. However, adjuvants used with encephalitogens to induce EAE produce non-specific effects interfering with the mechanisms involved in the autoimmune response to the central nervous system (CNS) tissue. It is therefore important to establish a more suitable model of EAE for analysis of autoimmune phenomena resembling those operative in MS. Here we report that EAE can be induced regularly in Dark Agouti (DA) strain of rats with spinal cord tissue without any adjuvant, as judged by both clinical and histological parameters. The incidence and severity of EAE depended on the origin of the encephalitogen, the rat versus guinea pig spinal cord homogenate being more efficient. Furthermore, EAE could be reinduced in animals which had recovered from disease that had been induced actively with encephalitogen alone, suggesting the role of adjuvant-generated non-specific mechanisms in resistance to reinduction of EAE. Thus, EAE induced in DA rats with encephalitogen alone provides a reproducible model for defining pathogenically relevant events in CNS autoimmunity devoid of the potentially misleading effects of adjuvants.

Apoptosis is a type of programmed cell death, characterized by chromatin condensation associated with activation of an endogenous endonuclease and fragmentation of DNA into oligonucleosomal sized segments, which is considered to be the biochemical hallmark of apoptosis. In this study, it was shown that despite inhibition of DNA fragmentation by zinc ions, the early apoptotic morphological changes, induced by colchicine or nocodazole, take place in the nuclei of thymocytes.

Based on the possibility of tumor necrosis factor (TNF)-α to perform multiple and opposite biologic effects, we simultaneously investigated in vitro its effects on intracellular lactate dehydrogenase (LDH)-H and LDH-M isoenzyme activity and morphological characteristics following induction of apoptosis in peripheral blood mononuclear cells (PBMC) of non-Hodgkin's lymphoma patients (NHL) prior to and after the end of applied chemotherapy. TNF-α showed a significant increase (p<0.05) of LDH-H and LDH-M activity in sonified PBMC of healthy controls after 18 h cultures accompanied with an increase of apoptotic index (AI) from 2.3 to 16.2%. Contrary to this, in PBMC of NHL patients prior to therapy TNF-α induced a significant decrease (p<0.05) of LDH-H isotype activity. In patients after administration of chemotherapy, TNF-α in a dose of 100 U/ml induced a significant increase (p<0.05) of LDH-M isotype activity, but not of LDH-H. In the PBMC of NHL patients prior to chemotherapy, TNF-α in vitro induced an increase of AI from 2.8 up to 6.8%, while in PBMC of NHL patients after applied chemotherapy AI changed from 7.2 to 14.4%. However, there was no significant difference in the increase of apoptosis in PBMC of NHL patients with high-grade malignancy and high rate response among patients who received first-line therapy, high-dose therapy, or third-line therapy regimens after in vitro TNF-α treatment. These results indicated different susceptibilities of PBMC of NHL to TNF-α when effects were analyzed by determination of intracellular LDH isotype profile and induction of apoptosis prior to and after administration of therapy in comparison to effects on healthy controls PBMC.