[Evaluation of the preventive role of two min-salen complexes in induction of steatohepatitis in rats]

Nonalcoholic steatohepatitis [NASH], a stage of fatty liver, occuring in individuals with little or no alcohol consumption, is characterized by macro-and microvesicular steatosis with inflammation, ballooning degeneration, hepatocyte necrosis, Mallory bodies and fibrosis. It has been suggested that oxidative stress might play an important role in the pathogenesis and progress of NASH. The aim of present study was to determine the preventive effect of catalytic antioxidants [two Mn-salen complexes] on diet-induced steatohepatitis in rats. NASH was induced in male N-Mary rats by feeding them with a methionine-choline deficient [MCD] diet for 14 weeks. The rats were randomly assigned to receive vitamin C, EUK-8, EUK-134 [n=5, 30 mg/Kg/day] or vehicle orally. At the end of the experiment, sera biochemical analyses and histopathological examination of liver samples were performed. Treatment of rats with Mn-salens and or vitamin C significantly reduced the sera cholesterol, glucose, aminotransferases and alkaline phosphatase activities, the extent of lipid peroxidation and protein carbonylation whereas the weight and HDL level were significantly increased. In addition, these compounds improved NASH pathological features in liver of MCD fed rats. SPSS statistical software was used for statistical analysis, with P values of less than 0.05 being considered statistically significant. Based on the present data, supplementation of Mn-salen complexes could be beneficial in the prevention of nonalcoholic steatohepatitis in rats

[Effect of adenosine 5-triphosphate on cell cycle of human acute myeloid leukemia KG1 cells during S phase]

Adenosine 5-triphosphate [ATP] not only is the current energy source of all cells but also plays critical role in triggering signaling pathways leading to apoptosis or differentiation. In recent years many investigations have reported anti-cancer activity of ATP on different cell lines. Also several mechanisms have been proposed for its mechanism of action and it appears that the mechanism depends on the cell type. In the present study the effects of ATP on human leukemia KG1 cell line as an experimental model of AML and mechanistic approach was studied. KG1 cells were cultured and treated with different concentrations of the ATP [50-1000 micro M] for various time intervals [24-72 hours]. The Effect of ATP on cell proliferation was studied by MTT assay. Apoptosis was studied by flowcytometery, fluorescent microscopy and DNA fragmentation assay. Cell cycle was analyzed using flowcytometery. The effects of ATP gamma S [un-degradable agonist of ATP] and degradable products of ATP such as AMP, ADP and adenosine were studied to evaluate its mechanism of action. Data were analyzed by student-t-test [p<0.05]. ATP inhibited growth and induced S-phase cell cycle arrest at 24 h to 72 h in concentration between 100-1000 micro m [p<0.05] along with apoptosis. In addition, results showed that these effects of ATP on KG1 cell line were made through P2X[7]receptors. Because current AML therapy methods based on chemotherapy are not so effective and have side effects, according to the results of present study ATP can be used as an effective compound alone or in combination of other drugs to treat of AML

Proliferation inhibition, cell cycle arrest and apoptosis induced in HL-60 cells by a natural diterpene ester from Daphne mucronata

Gnidilatimonoein [Gn], a new diterpene ester from Daphne mucronata, possesses strong anti-metastasis and anti-tumor activities. In this study, its apoptosis and differentiation capabilities were evaluated by using the leukemia HL-60 cell line. Cell prolifaration inhibition was estimated by MTT assay. The occurrence of apoptosis was evaluated by EtBr/AO double staining technique, cell cycle analyses and detection of apoptotic cells by Annexin V-FITC and propodium iodide [PI]. Differentiation of the cells was determined by NBT reduction assay and the expression of specific cell surface markers such as CD 14 and CD1 Ib, were analyzed by flow cytometry. The drug decreased the growth of the cells dose- and time-dependently and the IC[50] was found to be 1.3 microM. Our data suggested that Gn induced both monocytic differentiation and apoptosis among HL-60 cells. In addition, cell cycle analyses showed an increase in Gl phase population by 24 hrs, which was gradually replaced by Sub-Gl cell population [apoptotic cells] by 72 hrs. Based on these data, the Gn-treated HL-60 cells displayed differentiation-dependent apoptosis. Thus, Gn might be a good candidate for differentiation therapy of leukemia, pending full biological evaluation of the compound among the wide array of leukemia cells

[Dendrostellera lessertii extract effects on TNF-alpha release and its receptors down regulation on cultured human monocytes]

We investigated the mechanism of action of Dendrostellera lessertii effects on decreasing size of adeno-carcinoma of rat intestine and breast tumors. This purpose followed by assessing its effects on TNF-alpha and TNF-alpha receptors on cultured human monocytes. The breast and intestine tumors were induced in rats by DMBA and DMH, respectively. Human monocytes isolated by adhesion procedure. TNF- alpha in cultured media were measured by sensitive biotin-streptoavidin ELISA method and radio iodination was used for TNF- alpha receptors determination on human cultured monocytes. Oral administration of Dendrostellera lessertii extract during 20 consecutive weeks reduced significantly the diameter of tumor or eliminated them totally. Our data indicated that the plant extract at various doses did increase TNF-alpha release and in a time dependent manner decreases the TNF- alpha receptors in less than 90 minutes significantly in cultured human monocytes. Dendrostellera lessertii extract [H2O/EtOH] decreases the size of rat adenocarcinoma breast tumors. Our data support that the extract probably act through increasing TNF-alpha releasing and decreasing TNF-alpha receptors on cultured human monocytes

Immunologic prevention of IDDM by oral administration of glutamic acid decarboxylase

We have investigated the preventive effects of oral administration of isolated E.coli glutamic acid decarboxylase [GAD] in animal models. Based on our results, the blood glucose levels were reduced by oral administration of GAD to rats 14 days before intraperitoneal injections of streptozocin [40 mg/kg on five consecutive days]. On the other hand, oral administration of GAD to rats before streptozocin treatment significantly [P< 0.05] reduced the levels of GAD - specific antibodies and improved the in vitro proliferative responses of splenocytes to Con A. These data demonstrate that oral GAD administration probably generates active cellular mechanisms that suppress the disease and raise the possibility of using E.coli GAD as a new means for the prevention of autoimmune diabetes

Screening for starch-hydrolysing bacteria

Screening of 3000 soil samples collected from cities of four different provinces of Iran for starch-hydrolysing bacteria revealed that the nature is enriched with Streptomyces species capable of producing amylolytic enzymes. Among the bacterial isolates, one of the high starch degrading strains was selected for further microbiological identification and also amylolytic enzyme[s] characterization. The purified isolate, streptomyces species strain RY48,produces almost four times more amylolytic enzyme[s] than Bacillus subtilis [PTCC1254]on agar plates. Based on the action pattern of its amylolytic enzymes on the boiled maize starch, the purified species possesses in the logphase an amylolytic activity which is different from the amylolytic activity of the stationary phase. The secreted amylolytic enzymes which are both endolytic type and show different activity bands on native polyacrylamide gel, act independently on starch molecules

Significant changes in the activity of GABA transaminase and succinate semialdehyde dehydrogenase of mouse hypothalamus following peripheral injection of cholecystokinin-8 and/or caerulein

The activities of 4-aminobutyric-2-oxoglutaric acid transaminase [GABA-T] and succinate semialdehyde dehydrogenase [SSADH] were determined in mouse hypothalamus after peripheral injections of cholecystokinin-8 [CCK-8] and/or caerulein [CLN]. GABA transaminase activity was measured utilizing endogenous succinate semialdehyde dehydrogenase to convert the product of GABA-T, succinate semialdehyde, to succinate. The concurrently formed NADH was used as an estimate of GABA-T activity. Similarly, the activity of SSADH was determined in terms of NADH. Injection of CCK-8 and/or CLN inhibited the GABA-T and SSADH activities in dose-dependent responses. The activities of GABA-T and SSADH were diminished by 52 and 66% respectively. 30 minutes after injection of CCK-8 [50 micro g/kg body weight].Similarly, peripheral injection of CLN [50 micro g/kg body weight] reduced the activity of GABA-T and SSADH by 56 and 65% respectively, in 30 minutes. Using in vitro models, the full activities of GABA-T and/ or SSADH, after incubation with CCK-8 and/or CLN, were restored following 30 hours of dialysis at 4°C. These results indicate direct and reversible interactions between the catabolizing enzymes of GABA [GABA-T and SSADH] and the peptides CCK-8 and CLN