Zofenopril antitumor activity in mice bearing Ehrlich solid carcinoma: Modulation of PI3K/AKT signaling pathway

Angiotensin-II (AgII) is thought to be crucial for tumor growth and progression. Moreover, hydrogen sulfide (H2S) performs a controversial action in cancer pathology. Zofenopril (ZF) is an angiotensin-converting enzyme (ACE) inhibitor with H2S donating properties. Hence, this study aims at investigating the tumor suppressor activity of ZF and elucidating the involved trajectories in Ehrlich's solid tumor (EST)-bearing mice. EST was induced by the intradermal injection of Ehrlich's ascites carcinoma cells into femoral region. All parameters were assessed after 28 days post-inoculation or one-week thereafter. ZF treatment resulted in significant reduction of tumor weights with marked decrease in IL-6 and VEGF levels in serum, and tumor Ag II and CEA contents. Additionally, the administration of ZF downregulated the tumor gene expression of cyclin-D, ACE-1, and Bcl2 and upregulated the proapoptotic gene, BAX. Moreover, ZF increased CBS gene expression, which is a major contributor to cellular H2S production. In addition, ZF was able to reduce the protein expression of PI3K, pAKT, pGSK-3ß, and NFκB. Our study has provided novel insights into the possible mechanisms by which ZF may produce its tumor defeating properties. These intersecting trajectories involve the interference between PI3K/Akt and CBS signaling pathways

Efeito do tratamento com melatonina sobre a produção de metástases neoplasias / Result of the treatment with melatonin inthe production of neoplasic metastasis

Introdução: Neoplasias são células com proliferação e diferenciação anormais. Quando essas células tornam-se capazes de originar outras células em tecidos e vasos diferentes do inicial são denominadas metástases. A melatonina (N-acetil-5-metoxitripamina) é um hormônio secretado pela glândula pineal e que tem associação com o controle celular tumoral. Objetivo: pretendeu-se avaliar o efeito do tratamento com melatonina sobre a produção e crescimento de metástase linfática do tumor sólido de Ehrlich (TE) em camundongos. Método: foram empregados 14 camundongos distribuídos em 2 grupos: controle (GC, N = 07 / 0,1ml de solução fisiológica, via oral, 1x/dia) e teste (GT, N = 07 / 10mg/kg de melatonina, via oral, 1x/ dia). Todos os animais foram inoculados com 10 6 células tumorais no coxim plantar da pata traseira direita. Resultados e Discussão: D=decorridos 17 dias de tratamento os animais foram eutanasiados, removemos as 02 patas traseiras para avaliar o peso da massa tumoral sendo que o grupo controle apresentou peso maior (GC = 0,62 ± 0,14). Também foi removido o linfonodo poplíteo para mensuração da área, constatando redução significativa no grupo teste (GT = 4,37 ± 1,58). A redução da área do linfonodo pode ser associada a uma redução no número de células tumorais presentes nos linfonodos (GT = 62,8 ± 13,07). Conclusão: Concluímos que o tratamento com melatonina reduziu significativamente o crescimento tumoral e metastático do TE.

Introduction: Neoplasms are cells with unusual proliferation and differentiation. When these cells become able to generate other cells in material and veins different from the beginning one arenamed metastasis. The melatonin (N-acetil-5-methoxytryptamine) is a hormone secreted by the pineal gland and it has association with the tumor cell control. Objective: the general aim was to evaluate the treatment result with melatonin on the metastasis lymphatic production and growth of the Ehrlich Tumor in mice. For this experience, 14 mice were used and shared in 2 groups: control (GC, N = 07 / 0,1ml of sterilizing solution, oral, once a day) and test (GT, N = 07 / 10mg/kg of melatonin, oral, once a day). All the animals were inoculated with 106 tumor cells in the footpad of the right back paw. Results and discussion: after 17 days of treatment the animals were euthanized and 2 back paws were removed to evaluate the tumor bulk weight considering that the control group was heavier (GC = 0,62 ± 0,14). The popliteallymph node was also removed for the area measurement where asmaller area for the test group was observed (GT = 62,8 ± 13,07). Conclusion: we concluded that the treatment with melatonin meaningfully reduced the metastatic growth.

Histopathological evaluation of tumor necrosis and volume after cyanogenic chemotherapy

PURPOSE: To determine the percentage of tumoral necrosis and volume after cyanogenic chemotherapy. METHODS: Histopathological findings of 20 Swiss mice inoculated subcutaneously in the left abdominal wall with 0.05 ml of cell suspension containing 2.5 x 105 viable cells of the Ehrlich tumor were evaluated. The tumor response to cyanogenic chemotherapy was determined using a system that comprises two inhibition factors of tumor growth by calculating the percentage of necrosis in the tumor tissue and calculation of tumor volume in treated animals relative to that in control animals. The importance of this system has been validated by the correlation between tumor inhibition in the groups treated with the respective percentages of necrosis. RESULTS: While the control group presented an average of 13.48 ± 14.71% necrosis and average tumor volume of 16.18 ± 10.94, the treated group had an average of 42.02 ± 11.58 and 6.8 ± 3.57, respectively. The tumor inhibition was significantly associated with treatment (p=0.0189). The analysis of necrosis percentage showed a significant prognostic importance (p=0.0001). CONCLUSION: It is concluded that the effect of cyanogenic chemotherapy showed strong inhibitory action of tumor growth, as well as an increase in its area of necrosis. .

Sulfane sulfur deficiency in malignant cells, increasing the inhibiting action of acetone cyanohydrin in tumor growth

PURPOSE: To demonstrate the irreversible poisoning action of the acetone cyanohydrin (AC) in malignant cells. METHODS: Thirty male Swiss mice were inoculated with 1x10³ Ehrlich tumor (ET) cells. The mice were divided into three groups (n=10): CG (saline); ACG1 (1.864 mg/Kg of AC) and ACG2 (2.796 mg/Kg of AC), treated every 48 hours from day 3 until day 13. On day 15 the mice were euthanized and the number of viable cells in ascites was determined. In the meantime, ET cells were incubated with AC (0.5, 1.0, 2.0 μg/mL). Cell viability and percentage of growth inhibition (PGI) were checked after one, two, three, four, 18 and 24 hours. RESULTS: There was reduction in volume and number of viable cells in ACG1 and ACG2 compared to CG. In ACG1 one of the animals did not present ascites. In ACG2 two mice did not present ascites and in CG none of the mice present ascites. The action of AC was dose and time dependent and there was no significant difference among the three doses. CONCLUSION: The acetone cyanohydrin promoted reduction of the tumor and also prevented tumor development in 20% of the treated animals.

Effect of cyhalothrin on Ehrlich tumor growth and macrophage activity in mice

Cyhalothrin, a pyrethroid insecticide, induces stress-like symptoms, increases c-fos immunoreactivity in the paraventricular nucleus of the hypothalamus, and decreases innate immune responses in laboratory animals. Macrophages are key elements in cellular immune responses and operate at the tumor-host interface. This study investigated the relationship among cyhalothrin effects on Ehrlich tumor growth, serum corticosterone levels and peritoneal macrophage activity in mice. Three experiments were done with 10 experimental (single gavage administration of 3.0 mg/kg cyhalothrin daily for 7 days) and 10 control (single gavage administration of 1.0 mL/kg vehicle of cyhalothrin preparation daily for 7 days) isogenic BALB/c mice in each experiment. Cyhalothrin i) increased Ehrlich ascitic tumor growth after ip administration of 5.0 x 106 tumor cells, i.e., ascitic fluid volume (control = 1.97 ± 0.39 mL and experimental = 2.71 ± 0.92 mL; P < 0.05), concentration of tumor cells/mL in the ascitic fluid (control = 111.95 ± 16.73 x 106 and experimental = 144.60 ± 33.18 x 106; P < 0.05), and total number of tumor cells in the ascitic fluid (control = 226.91 ± 43.22 x 106 and experimental = 349.40 ± 106.38 x 106; P < 0.05); ii) increased serum corticosterone levels (control = 200.0 ± 48.3 ng/mL and experimental = 420.0 ± 75.5 ng/mL; P < 0.05), and iii) decreased the intensity of macrophage phagocytosis (control = 132.3 ± 19.7 and experimental = 116.2 ± 4.6; P < 0.05) and oxidative burst (control = 173.7 ± 40.8 and experimental= 99.58 ± 41.7; P < 0.05) in vitro in the presence of Staphylococcus aureus. These data provide evidence that cyhalothrin simultaneously alters host resistance to Ehrlich tumor growth, hypothalamic-pituitary-adrenocortical (HPA) axis function, and peritoneal macrophage activity. The results are discussed in terms of data suggesting a link between stress, HPA axis activation and resistance to tumor growth.

Effect of L-Arginine and L-NAME treatments on polymorphonuclear leukocytes and mononuclear cells influx during tumor growth / Efeito dos tratamentos com L-Arginina e L-NAME sobre o influxo de leucócitos polimorfonucleares e células mononucleares durante o desenvolvimento tumoral

PURPOSE: Evaluate polymorphonuclear leukocytes (PMN's) and mononuclear cells (MN's) involvement in the Ehrlich´s solid tumor (ET) growth. METHODS: 90 Swiss mice were inoculated with 10(7) tumor cells (sc), distributed in three groups and treated once a day, via intraperitoneal (ip), with 0.1ml of diluent, L-Arginine (20mg/Kg) or L-NAME (20mg/Kg). After 7, 15 and 30 days of treatment, ten animals of each group were euthanized, the tumor mass was removed, processed and fixed for HE. Later, a morphometric analysis of the total area, parenchyma, necrosis, tumor stroma and PMN's leukocytes and MN's cells influx was performed. RESULTS: The L-Arginine treatment increased PMN's influx in the initial stage, whereas L-NAME reduced it. Our data suggests that NO effect on PMN's migration is dose-dependent. On the other hand, the MN´s cells influx was reduced by L-NAME treatment at all evaluated periods and at the same periods an increase in tumor growth was observed. CONCLUSION: At initial stages of tumor implantation, both PMN's leukocytes and MN's cells act together to control ET development.

OBJETIVO: Avaliar o envolvimento de leucócitos polimorfonucleares (PMN's) e células mononucleares (MN's) no crescimento do Tumor Sólido de Ehrlich (TE). MÉTODOS: 90 camundongos Suíços foram inoculados com 10(7) células tumorais (sc), distribuídos em três grupos e tratados uma vez ao dia, via intraperitoneal (ip), com 0.1ml de diluente, L-Arginina (20mg/Kg) ou L-NAME (20mg/Kg). Após 7, 15 e 30 dias, dez animais de cada grupo foram eutanasiados, a massa tumoral foi removida, processada e corada pela HE. Posteriormente, foi realizada análise morfométrica das áreas total, parênquima, necrose, estroma e influxo de leucócitos PMN's e células MN's. RESULTADOS: O tratamento com L-Arginina favoreceu o influxo de PMN's em períodos iniciais, enquanto o tratamento com L-NAME o reduziu. Nosso estudo sugere que o efeito do ON sobre a migração de PMN's é dose-dependente. Por outro lado, o influxo de células MN´s foi contido pelo tratamento com L-NAME em todos os períodos avaliados, mesmos períodos em que se observou um aumento no crescimento tumoral. CONCLUSÃO: Em fases iniciais do implante tumoral, ambos, leucócitos PMN's e células MN's, atuam juntos no controle do desenvolvimento do TE.

Efeito do hipotireoidismo no tumor de Ehrlich sólido em camundongos fêmeas castradas e não castradas / Effect of hypothyroidism on the solid form of the Ehrlich tumor in intact or castrated adult female mice

Foi estudado o efeito do hipotireoidismo, induzido pelo propiltiouracil (PTU), no tumor de Ehrlich sólido, implantado em camundongos fêmeas adultas castradas ou não. Foram utilizados 40 animais distribuídos em quatro grupos: hipotireóideo castrado, hipotireóideo não castrado, eutireóideo castrado e eutireóideo não castrado. Os animais receberam uma injeção de células neoplásicas no coxim plantar esquerdo. A curva de crescimento tumoral foi determinada por mensurações da pata inoculada durante 12 dias quando os animais foram necropsiados. A hipofunção tireoidiana reduziu o tamanho do tumor de Ehrlich nos animais castrados. Embora o crescimento neoplásico tenha sido menor, o diâmetro nuclear médio e o número de regiões organizadoras de nucléolos (NORs) e de mitoses/campo foram maiores. Conclui-se que o hipotireoidismo retarda o crescimento do tumor de Ehrlich sólido, sem alterar as características celulares de malignidade, que o efeito isolado da castração causa alterações discretas e que a associação hipotireoidismo-castração potencializa o retardo do crescimento do tumor de Ehrlich sólido.

Effect of a submaxillary gland extract on Ehrlich tumor growth in mice

Ablation of host submaxillary glands modifies Ehrlich tumor growth and tumor-infiltrating leukocytes, possibly by modifications in the serum level of growth factors produced by this gland. To extend this research, 7-month-old male EPM-1 mice (N = 30) were divided into two groups: 1) inoculated with tumor cells previously incubated with submaxillary salivary gland extract (SGE) in PBS for 30 min at 37 percent; 2) inoculated with tumor cells previously incubated with PBS, under the same conditions. Animals were inoculated into the footpad with 40 µl of a suspension containing 4.5 x 107 tumor cells/ml, and footpad thickness was measured daily for 10 days. Sections and smears of tumor cells were prepared from the tumor mass to determine mitosis frequency, percent of tumor cells immunopositive to nerve (NGF) and epidermal (EGF) growth factors and percent of tumor-infiltrating leukocytes. The incubation of tumor cells with SGE produced a tumor reduction of about 30 percent in size. This effect was not related to loss of cell viability during incubation, but a 33 percent increase 0.05 in the percentage of dead or dying tumor cells and a 15 percent increase in the percent of NGF/EGF-positive tumor cells 0.01 were observed in vivo at the end of experiment. Tumor-infiltrating lymphocytes and mitosis frequency did not differ between groups. These data suggest a direct effect of factors present in SGE on tumor cells, which induce degeneration of tumor cells

Efectos de la corriente eléctrica directa en el tumor murino subcutáneo de Ehrlich. I: Estudios de necrosis y volumen del tumor en estadíos avanzados / Direct eletric current effects on the Ehrlich subcutaneous murine tumor. I: Necrosis and volume of tumor studies in advanced stages

La electroterapia con corriente eléctrica direta se aplicó a un modelo de tumor murino subcutáneo (tumor de Ehrlich). La corriente fue suministrada a través de electrodos de Pt, donde el cátodo fue introducido directamente en los tumores y el ánodo subcutáneamente en la vencidad de éstos. Después de la electroterapia de un solo estímulo se observó que la disminución del volumen y el porcentaje de necrosis de los tumores fueron significativos y dependientes de la intensidad de corriente directa (1,8 y 4 mA). En la electroterapia repetitiva con 1,8 y 4 mA en diferentes días y zonas del tumor, también se observó disminución del volumen del tumor. Los grupos controles en ambos casos fueron sometidos a las mismas condiciones, pero no se les suministró corriente eléctrica. Estos resultados indican que la electroterapia en estadíos avanzados también puede ser una terapia antitumoral efectiva y que sus efectos son mejores a mayores intensidades de corriente. Se concluyó que la electroterapia para estos estadíos debe aplicarse mediante el empleo de un arreglo de electrodos dispuesto simétricamente en todo el tumor o en secciones de éste por separado, con el objetivo de disminuir los altos voltajes que se aplican entre los electrodos.

Antitumour and radioprotective action of Podophyllum hexandrum.

A significant antitumour effect of P. hexandrum, a herb thriving at Himalayas (2500-4000 m), was observed in strain 'A' mice carrying solid tumours developed by transplanting Ehrlich ascites tumour (EAT). Subtoxic well tolerated sequential doses of aqueous extract of P. hexandrum (a daily dose of 34.5 mg/kg b.w. for 15 days) enhanced tumour doubling time (TDT) from 1.94 +/- 0.26 days to 19.1 +/- 2.5 days. However, no synergism was revealed between radiation and P. hexandrum, though both independently manifested antitumour effects. In normal mice, pre-irradiation administration of extract of P. hexandrum protected mice in a dose dependent manner (optimal dose being 34.5 mg/kg body.wt. rendering 72% survival for 30 days) against whole body lethal irradiation of 10 Gy. Radioprotective properties of P. hexandrum were found to be comparable to synthetic radioprotectors like diltiazem etc.

Substance P does not modify mononuclear cell migration into Ehrlich tumor mass

In the present study, seven adult male mice were inoculated with Ehrlich tumor into the footpad after local substance P release was blocked by neurectomy of the sciatic and saphenous nerves. The contralateral footpad was also inoculated but sham-operated, and used as control. This procedure did not modify the percent of CD4+ (about 1-2 per cent), CD8+ (about 1-3 per cent), macrophages (about 21-22 per cent), lymphocyte B (about 0-1 per cent) and NK (about 1-2 per cent) mononuclear cells present among tumor cells. These data suggest that chemotactic activity of substance P may not be relevant in this situation because the lack of this neurotransmitter (checked by immunohistochemistry) secondary to neurectomy did not change the cell migration profile into tumor mass.

The influence of social isolation and peripheral innervation on Ehrlich tumor growth in mice

The relationship between social isolation and Ehrlicha tumor growth was investigated in seven male NIH mice about 2 months old living separately in small cages for 28 days. fifteen control animals were kept grouped in conventional cages (10 animals in one and 5 in another) for the same period. After this period, 40 to 50 µl of a cell tumor suspension at a concentration of 1 to 5 x 10**7 tumor cells/ml was incolulated into the footpad and footpad size was measured for 10 days. Isolated mice presented a 30 percent reduction in tumor growth. Sciatic and saphenous neurectomy in one leg of 5 isolated mic (experimental) and 5 grouped mice (control) performed 7 days before tumor inoculation abolished this difference, and more tumor growth was observed in the neurectomized paw compared to the non-neurectomized apw. The subordinate x dominant social relationship established between mice living in groups of two per cage (seven cages) did not modify the growth of tumor inoculated under the same conditions comapared to the first experiment. We conclude that social isolation and an intact peripheral innervation are associated with reduced tumor growth, but dominance behavior has no effect

An experimental study on the lymphatic dissemination of the solid Ehrlich tumor in mice / Estudo experimental sobre a disseminaçäo linfática do tumor de Ehrlich na forma sólida em camundongos

As metástases para linfonodos regionais representam fase importante na disseminaçäo neoplásica. Os mecanismos que concorrem para este processo säo pouco conhecidos, devido provavelmente à escassez de modelos experimentais adequados. O objetivo do presente estudo é o de caracterizar o tumor de Ehrlich como modelo para o estudo da disseminaçäo linfática em camundongos. Para tanto, animais foram inoculados com células tumorais no coxim plantar e seus linfonodos poplíteos foram colhidos vários tempos após a inoculaçäo, com a finalidade de avaliar seu peso, aspectos histopatológicos e quantificar os mastócitos, já que estas células parecem estar implicadas na resposta do hospedeiro ao tumor. A migraçäo das células tumorais para os linfonodos poplíteos foi detectada a partir de 1 hora após a inoculaçäo. O crescimento do tumor sólido no coxim plantar foi acompanhado até 30 dias após a inoculaçäo, e as alteraçöes histopatológicas foram estudadas durante esse período. O tumor de Ehrlich foi considerado um modelo experimental adequado para o estudo da disseminaçäo linfática

Antitumor effects of Rhodium (II) citrate in mice bearing Chrlich tumors

Rhodium II citrate was tested in mice for acute toxicity, antitumoral activity against Ehrlich ascites carcinoma and inhibition of DNA synthesis by Ehrlich tumor, malignant adrenocortical cells (Y-1) and normal adrenocortical cells (AR-1)_. At ip doses up to 260 mg/Kg, the compound had no toxic effects for up to 14 days. The same total dose given over 4 days significantly increased the survial rat of mice bearing Ehrlich ascites cells. Thymidine incorporation by Ehrlkich tumor, Y-1 cells in vitro was inhibited 50% by a.1 to 0.2 mM concentrations of the compound. We conclude that the increase survival of the tumor-bearing mice was due at least in part to the inhibition of DNA synthesis with a consequet reduction of cell division and tumor growth

Informe especial: estudios tendientes a determinar las posibles propiedades antitumorales del veneno de cobra y del complejo crotoxina A y B / Special report: studies to determine the possible antitumoral properities of Cobra venom and of crotoxin complex A and B

La presente investigación fue encomendada por el CONICET (Consejo Nacional de Investigaciones Cientificas y Técnicas) para determinar las posibles propriedades antineoplásicas del veneno de Cobra (Naja Naja Siamensis) VC) y del Complejo Crotoxina a y B (CCAB), purificado a partir del veneno de Crotalus durissus terificus (cascavel sudamericana). La coordinación de las investigaciones estuvo a cargo de los Dres. Baldi y Mordoh, y la ejecución de la parte experimental fue llevada a cabo por los restantes autores. Se utilizaron diversos sistemas experimentales: 1) lúneas celulares in vitro: de origen murino, normales (3T3 A31), o transformadas (M-A31, Ki-A31 y BP-A31) o de origen humano (adenocarcinoma mamario: MCF-7 y T47D). el efecto de las drogas fue determinado a 1, 10 y 100 ng/ml de VC y CCAB, solas o en combinación. En ninguna de las líneas celulares mencionadas se observaron cambios significativos en la velocidad de crecimiento o en la morfología celular; 2) desarrollo in vivo del Sarcoma 180 (S180) en ratones Balb/c: el VC a dosis de 21 ó 26 ng/g (inyecciones i.p. a los días 10, 11, 20, 21, 30 y 31 post-inoculo tumoral) no afectaron el crecimiento ni la sobrevida de los animales. Dosis de CCAB de 6 ng/g o 9 ng/g ]con el mismo esquema de inoculación anterior) no afectaron el crecimiento de s180 hasta los 25 días de desarrollo tumoral. Entre los días 25 y 30 la dosis de 9 ng/g determinó una evolución tumoral más rápida. La combinación de 13 ng/g VC y 4,5 ng/g CCAB con iguales tiempos de inyección no afectaron el desarrollo tumoral. La histología de los tumores de los animales tratados y controles no evidenció cambios significativos; 3) desarrollo in vivo del carcinoma de Ehrlich en ratones Swiss: se probó el efecto de CCAB (9 ng/g inyectados i.p. a los días 8, 9, 16, y 17) sin obtenerse modificación del desarrollo tumoral;...

Estudos preliminares da imunidade celular no tumor de Ehrlich / Preliminar studies of cellular immunity in the Ehrlich

O sistema imune dos animais é constituido por linfócitos, macrofagos, células relacionadas e seus produtos solúveis, encontrados em diferentes tecidos e órgäos. No tumor de Ehrlich em camundongos, o fenômeno de citotoxicidade dependente de anticorpo foi demonstrada ser eficiente. O critério empregado para avaliar a influência dos mediadores foi a medida da sintese do DNA da célula, pela quantidade de 3H-timidina incorporada após um pulso de 2 horas, pela subseqüente contagem da radioatividade precipitada pelo ácido tricloroacético 10%. A atividade supressora do lipopolissacarideo bacteriano foi estudada tanto pelos fatores solúveis liberados pelos macrófagos, como também nos macrófagos tratados em contato com as células tumorais. Os fatores envolvidos no tumor de Ehrlich aparentemente säo múltiplos, havendo necessidade de estudos posteriores para o entendimento do complexo fenômeno da imunidade celular

Evoluçäo do carcinoma mamário: novos parâmetros imunopatológicos de avaliaçäo, estudo experimental em camundongos (MuMT): IV. Correlaçäo entre hemograma, esplenograma e células do fluído ascítico / Course of mammary carcinoma: new immunopathological parameters of evaluation, experimental study in mice (MuMT): IV. Correlation between hemogram, splenogram and ascitic fluid cells

Células da hematopoie esplênica (esplenograma), do hemograma e do líquido ascítico de camundongos inoculados intraperitonialmente com MuMT (carcinoma de Ehrlich), foram estudadas isoladamente pelos autores, nos trabalhos anteriores I, II e III. O presente trabalho estuda comparativamente os resultados obtidos, estabelecendo uma correlaçäo entre as variaçöes observadas nas diferentes linhagens celulares

Evoluçäo do carcinoma mamário: novos parâmetros imunopatológicos de avaliaçäo; estudo experimental em camundongos (MuMT), III. Líquido ascítico / Course of breast carcinoma: new immunopathological parameters of evaluation; experimental study in mice (MuMT), III. Ascitic fluid

Cem camundongos Swiss fêmeas inoculados por via intraperitonial com células tumorais de MuMT (carcinoma de Ehrlich, forma ascítica) e sacrificados diariamente, em grupos de cinco animais, durante os 20 dias de experimentaçäo. A formaçäo do líquido ascítico foi constatada a partir do 3§ dia (0,28 ml), aumentando para 0,48 ml no 6§ dia, e atingindo o máximo de 15,28 ml próximo ao 20§ dia (morte dos animais). A proporçäo de células tumorais variou acentuadamente no decorrer dos 20 dias da experimentaçäo. As células encontradas no 2§ dia se apresentaram 95% lisadas e as células íntegras inexistentes. Ao contrário, no fim da experimentaçäo constatou-se 6% de células lisadas e 85% de células íntegras. Nos primeiros dias a lise predominante foi a de tipo citotóxico, desencadeada pelas plaquetas, linfócitos T e monócitos. Entre o 6§ e 10§ dia a lise foi devida aos granulócitos. A lise por mecanismo näo citotóxico foi inversa ao porcentual de polimorfonucleares neutrófilos, diminuindo de 80% nos primeros 12 dias para 33% no 18§ dia