[Effect of sodium fluoroacetate on Ehrlich solid tumor and autochthonous sarcoma growth in mice].

Due to biochemical characteristics of toxic action of fluoroacetate on energetics and metabolism of cells, including tumor cells, it was interesting to testify sodium fluoroacetate (SFA) for its antitumor activity in vivo. We have estimated that SFA significantly inhibits growth of Ehrlich tumor carcinoma. In experiments with autochthonous induced by benzo[a]pyrene subcutaneous tumors, SFA was not active in monotherapy regime, though potentiated antitumor effect of cyclophosphamide, significantly increasing the relative number of mice with stabilized or decreased tumor volume as well as the duration of this effect. The data obtained render basis for additional studies of mechanism of antitumor effect of SFA.

Pesticide dichorvos induces early solid Ehrlich tumoral development associated with a non-protective pro-inflammatory response.

Prolonged exposure to dichlorvos (DDVP), a common pesticide used for food crops, has been related to the development of infections and malignancies. Macrophages are used as bioindicators of immunotoxicity; thus, evaluation of their activity in solid Ehrlich tumor-bearing mice (TBM) may be useful to evaluate the influence of pesticides on human health. To investigate the effects of low DDVP doses, Swiss mice were divided into the following groups: the DDVP group, composed of mice fed diets containing 10 mg/kg of DDVP; the TBM group, consisting of mice subcutaneously inoculated with 107 tumor cells/100 µl and fed a basal diet; the DDVP-TBM group, consisting of mice previously fed DDVP-containing diets for 28 days and then subcutaneously inoculated with tumor cells; and the control (CTRL) group, composed of mice fed a basal diet. After 7 and 21 days of tumor inoculation, the mice were euthanized; and after necroscopic examination, the neoplastic mass, organs, and intraperitoneal fluid were collected. Adherent peritoneal cells were cultivated to determine the production of H2O2 and TNF. Altogether, our results indicate that even at low doses, the intake of DDVP caused weight loss and increased tumor mass, which were associated with H2O2 production and high levels of TNF, a pro-inflammatory cytokine. These data are important as the exposure to pesticides, even at low doses, could potentially hinder the immune response against tumors and, consequently, create favorable conditions for their development.

Purification and partial characterization of two phospholipases A2 from Bothrops leucurus (white-tailed-jararaca) snake venom.

Two proteins with phospholipase A(2) (PLA(2)) activity were purified to homogeneity from Bothrops leucurus (white-tailed-jararaca) snake venom through three chromatographic steps: Conventional gel filtration on Sephacryl S-200, ion-exchange on Q-Sepharose and reverse phase on Vydac C4 HPLC column. The molecular mass for both enzymes was estimated to be approximately 14 kDa by SDS-PAGE. The N-terminal sequences (48 residues) show that one enzyme presents lysine at position 48 and the other an aspartic acid in this position, and therefore they were designated blK-PLA(2) and blD-PLA(2) respectively. blK-PLA(2) presented negligible levels of PLA(2) activity as compared to that of blD-PLA(2). The PLA(2) activity of both enzymes is Ca(2+)-dependent. blD-PLA(2) did not have any effect upon platelet aggregation induced by arachidonic acid, ADP or collagen, but strongly inhibits coagulation and is able to stimulate Ehrlich tumor growth but not angiogenesis.

Sulfobetaine (dimethylsulfoniopropionate) and glycine betaine show incompatible involvement in crucial Ehrlich ascites carcinoma in mice.

BACKGROUND/AIM: The role of methylation reactions in cancer was examined using the methylating agents, sulfobetaine [dimethylsulfonioproponate (DMSP)], and glycine betaine (GB), in murine crucial Ehrlich ascites carcinoma (EAC) for up to 10 days. RESULTS: DMSP administration in EAC-bearing mice mitigated EAC, while GB administration clearly promoted EAC. However, the immune cell profiles did not differ largely between animals receiving DMSP and those receiving GB. Moreover, DMSP and GB had merely any effects on proliferation of EAC cells in vitro. Injection of DMSP into normal mice interestingly led to macrophage accumulation in the peritoneal cavity in a dose-dependent manner at early rearing. CONCLUSION: These results indicate that GB promoted EAC by the methylation of cancer promotor gene, whereas DMSP ameliorated EAC by the accumulation of activated macrophages with a rapid response and long life span during cancer progression.

Effect of Sobatum on tumour development and chemically induced carcinogenesis.

The partially purified component of Solanum trilobatum named Sobatum was obtained from the petroleum ether/ethyl acetate (75:25) extractable portion. It was found to be cytotoxic in Dalton's Lymphoma ascites (DLA), Ehrlich ascites (EA) cell lines and tissue culture cells (L929 and Vero). Sobatum significantly inhibited peritoneal tumours induced by DLA and EA tumour cells. Sobatum was also found to reduce solid tumour growth in mice, when given either simultaneously or prophylactically, and is more active in simultaneous administration (EA). It was found that Sobatum was more active against EA cells-induced solid tumour than DLA-induced solid tumours. On exposure to 7,12-dimethylbenz(a)anthracene (DMBA), about 85.67% animals had induced skin carcinogenesis, which was significantly inhibited to 44.4% by the application of Sobatum. It can be concluded that the Sobatum has the ability to retard the development of solid tumours and DMBA-induced carcinogenesis.

[Structural dynamic properties of the cell membranes of Ehrlich ascites tumor associated with a polyamine deficiency caused by DL-difluoromethylornithine]. / Strukturno-dinamicheskie svoistva membran kletok astsitnogo raka Erhlikha pri defitsite poliaminov, vyzvannom DL-diftormetilornitinom.

The blocking of polyamine synthesis in cancer cell by a specific inhibitor (DFMO) results in an increase in membrane viscosity and in significant changes in cell deformability as determined by cell penetration through a nuclear filter with given porosity. Almost two-fold reduction of the penetration rate through the filter pores was registered for the DFMO-treated cells in spite of the fact that the cell size decreases after such a treatment. The number of cells penetrating through the filter after DFMO treatment is diminished due to an increasing resistance to penetration. The addition of putrescine to the incubation medium at physiological concentration restores all these parameters to the initial values. The possible association of these changes with differential sensitivity of cancer cells towards the inhibitor action depending on the stage of cell cycles is discussed.

Intervention in cyclophosphamide induced oxidative stress and DNA damage by a flavonyl-thiazolidinedione based organoselenocyanate and evaluation of its efficacy during adjuvant therapy in tumor bearing mice.

A novel flavonyl-thiazolidinedione based organoselenocyanate compound was synthesized and established as nontoxic at the doses of 2.5 and 5 mg/kg b.w. in mice. Oral administration of the compound in combination with cyclophosphamide (CP) resulted in an improved therapeutic efficacy which was mostly evidenced in terms of tumor burden and protection of normal cells. The adjuvant therapy was proved to be immensely significant in increasing the mean survivability of the tumor bearing hosts. Reduction in the tumor volume was manifested through the induction of apoptosis and generation of ROS in transformed cells. Moreover, the organoselenium compound could efficiently suppress CP-induced DNA damage, chromosomal aberration, hepatic damage and enhanced the activities of various antioxidant enzymes in normal cells.

[Growth control of experimental tumour. I. Host protection against tumour by previous inoculation of plasmatic membrane of tumour cell (author's transl)]. / Contrôle do crescimento de tumor experimental. I. Proteção do hospedeiro por inoculação prévia da fração de membrana plasmática de célula tumoral.

Proteins from plasmatic membrane of ascites and solid 20-methylcholantrene induced tumours cells in inbred mice and rats were obtained by isolation of vesicles of tumor cell membranes produced in glycerol solution. The tumour cells were not broken. In a syngeneic system the inoculation of the prepared protein with adjuvant resulted in protection of 50 to 100% of animals against challenge with a syngeneic tumour cells. The same results were obtained with Ehrlich ascites tumour. The lymphocyte cytotoxicity and blastic transformation of lymphocytes in immunized animals suggested a cellular cytotoxic immunity mediated by tumour specific antigen or perhaps by fetal antigen.

Effect of Ehrlich ascites tumour on the clinical course and pathology of mice having carbon tetrachloride-induced hepato-renal necrosis.

Ehrlich ascites tumour, administered intraperitoneally 18 hr following a dose of CCl4 by stomach tube, produces and irreversible illness characterised by failure to resolve extensive hepato-renal necrosis. Equally extensive hepato-renal necrosis occurs in animals given CCl4 and saline; such animals, however, remain clinically well and show rapid histological regeneration of both organs. Carbon tetrachloride given to mice on day 5 of tumour growth produces hepatic necrosis only, the kidney of such animals being immune to the necrotising effect of CCl4. Such animals remain well, and histological recovery of the liver is rapid. It is proposed that the Ehrlich tumour produces a "regeneration-inhibiting" toxin, active against the damaged liver and kidney; the CCl4-damaged kidney fails to excrete this toxin, hence the irreversibility of hepato-renal damage and a fatal outcome. A marked reduction of ascites volume as compared with controls was observed in those animals given Ehrlich tumour 18 hr after CCl4, but not in animals given CCl4 on day 5 of Ehrlich ascites tumour growth.

Considerations on the carcinogenicity of the mushroom poison gyromitrin and its metabolites.

Monomethylhydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH), but not N-methyl-N-formylhydrazine (MFH), a mushroom poison, can be oxidized by the weak oxidant 2,6-dichlorophenolindophenol. Hydrogen peroxide is formed by this oxidation, and has been found to cause decay of DNA in aqueous solution as measured by the decreased viscosity of a DNA solution in the presence of the hydrazines. Furthermore, MMH and UDMH but not MFH inhibit the incorporation of [3H]thymidine and [3H]uridine into DNA and RNA of Ehrlich ascites carcinoma (EAC) cells. These experiments show that MFH is an inactive compound in contrast to MMH and UDMH. Since the hydrolysis rate of MFH, to produce MMH, is low, it is concluded that MFH must be activated in vivo into toxic metabolites which are ultimately responsible for the known high carcinogenicity of MFH.

Trigonella foenum graecum (fenugreek) seed extract as an antineoplastic agent.

The antineoplastic effect of Trigonella foenum graecum seed extract has been evaluated in the Ehrlich ascites carcinoma (EAC) model in Balb-C mice. Intra-peritoneal administration of the alcohol extract of the seed both before and after inoculation of EAC cell in mice produced more than 70% inhibition of tumour cell growth with respect to the control. Treatment with the extract was found to enhance both the peritoneal exudate cell and macrophage cell counts. The extract also produced a significant antiinflammatory effect. We report here the antiinflammatory and antineoplastic effects, of Trigonella foenum graecum seed extract.

Studies on the modification of the cellular response to injury: effect of mannitol on Ehrlich ascites tumor cells following injury by anoxia or p-chloromercuribenzenesulfonic acid (PCMBS).

The possible protective effects of 30 and 180 mM mannitol added to the extracellular medium were studied in Ehrlich ascites tumor cells (EATC) injured by the nonpenetrating mercurial p-chloromercuribenzenesulfonic acid (PCMBS) or by anoxia. Protection was provided with 180 mM mannitol as observed by vital dye uptake, cell volume determinations, and electron microscopy studies in cells incubated for 1 hr in 1 mM PCMBS; however, no protection was observed after 2 and 4 hr. EATC injured by anoxia were not protected by 180 mM mannitol nor did 30 mM offer protection to cells following injury with either PCMBS or anoxia.

Níveis comparativos de estresse oxidativo em camundongos em duas situações do limite orgânico: overreaching induzido por treinamento de natação e câncer / Comparative oxidative stress levels in mice submitted to two situations of organic limit: overreaching induced by swimming training and cancer

O objetivo deste trabalho foi comparar concentrações de estresse oxidativo em camundongos da linhagem Balb-C submetidos a duas condições severas de alterações orgânicas: treinamento exaustivo de natação (overreaching - grupo OVER; n = 10) e inoculação por tumor ascítico de Ehrlich (grupo TAE; n = 10). A proposta foi analisar como as duas situações comprometiam o equilíbrio entre os sistemas oxidantes e antioxidantes. Foram investigados alguns marcadores de estresse oxidativo, tais como as substâncias reativas ao ácido tiobarbitúrico (TBARS) e concentrações da atividade da enzima antioxidante catalase (CAT) no hemolisado. Como marcadores de lesão celular, quantificaram-se concentrações plasmáticas das enzimas creatina quinase (CK) e aspartato transferase (AST); complementado; também se observaram padrões de alterações fisiológicas por meio da quantificação plasmática de creatinina e uréia. Como resultados mais importantes, pôde-se observar que, nas duas situações de limite orgânico, seja por exercício exaustivo (OVER) ou pela inoculação de TAE, houve queda abrupta na concentração da enzima CAT (decréscimos de 30 por cento; p < 0,01 e 72 por cento; p < 0,001, respectivamente, comparando-se com o grupo treinado - T). Quanto à concentração de peroxidação lipídica (TBARS), detectaram-se aumentos significativos para os grupos OVER e TAE em relação ao grupo T (52 por cento, p < 0,01; 90 por cento, p < 0,001, respectivamente). Níveis liberados de CK foram mais proeminentes no grupo OVER, enquanto que a quantidade de AST no plasma foi mais elevada no grupo TAE. Chegou-se à conclusão de que os organismos estudados possuem um mesmo perfil de estresse oxidativo em situações limites que envolvem exercício físico e doença. Tais resultados permitirão profissionais envolvidos com elaboração das cargas de treinamento físico a se preocuparem com os períodos recuperativos, o que impede a instalação do quadro de overreaching, o qual se mostrou tão severo...

The aim of this study was to compare oxidative stress levels in mice (Balb-C) submitted to two severe organic conditions: exhaustive swimming training (overreaching - OVER group; n = 10) and inoculation of the Ehrlich's Ascitic Tumor (EAT group; n = 10). Lipid peroxidation, quantified by thiobarbituric acid reactive substances (TBARS), and levels of antioxidant enzyme (catalase- CAT) were used as indicators of oxidative stress. Muscle damage levels were measured through plasma creatine kinase (CK), aspartate transaminase (AST) as well as blood creatinine and urea activities samples. As main results, it has been observed that in both situations, whether by exhaustive exercise (OVER) or inoculation of EAT, dramatic decrease in the catalase activity levels was present when compared with the training group (T) (30 percent; p < 0.01 and 72 percent; p < 0.001, respectively) with concomitant increase in plasma TBARS concentration (52 percent; p < 0.01 and 90 percent p < 0.001, respectively). Plasma CK levels were more prominent in the OVER group, while the amount of AST plasma was higher in the EAT group. We concluded that the same profile of oxidative stress was found in situations involving exhaustive exercise and pathology. These results will allow professionals involved with load training manipulation to be concerned with the rest periods, preventing hence the installation of overreaching, which in terms of oxidative stress, was as severe as a pathological conditions.

Influência de Agaricus blazei Murrill sobre o tumor sólido de Ehrlich e linfonodos poplíteos de camundongos / Influence of Agaricus blazei Murrill in solid Ehrlich tumor and popliteal lymph nodes in mice

Estudou-se a influência do tratamento diário com filtrado aquoso de Agaricus blazei Murrill (ABM) (25mg/ml), via oral, por 17 e 57 dias, em camundongos inoculados com tumor sólido de Ehrlich (TSE) por meio da curva de crescimento tumoral, do peso relativo do tumor, da contagem de regiões organizadoras de nucléolos (AgNORs) e dos padrões histológicos das massas tumorais e linfonodos poplíteos. Os animais que ingeriram o extrato aquoso do ABM por 57 dias apresentaram menor (P<0,05) crescimento do TSE, no segundo e terceiro dias, fase inflamatória do crescimento tumoral. Quanto ao peso relativo das massas tumorais, valores de AgNORs, padrões morfoistopatológicos do TSE e ocorrência de processos metastáticos, não houve alteração significativa (P>0,05) entre os animais tratados e não tratados.

The influence of daily administration of Agaricus blazei Murrill (ABM) aqueous solution (25mg/ml) during 17 and 57 days in mice bearing solid Ehrlich tumor was studied. Tumoral growth, tumoral and spleenic relative weights, nucleoly organization regions AgNORs values and tumor and popliteal lymph nodes histopathology were daily evaluated. The animals that received ABM during 57 days showed lower values (P<0.05) of tumoral growth on second and third days after the period corresponding to the inflammatory phase of tumoral growth. The relative weight of the tumor and AgNORs values were similar (P>0.05) between treated and non-treated animals. No difference in microscopic evaluation of the tumors in treated and non-treated animals was seen and metastasis in popliteal nodes of the tumor occurred in all the animals.