ascorbic-acid and Carcinoma--Ehrlich-Tumor

This work was carried out to compare the modifying roles of ascorbic and metformin during Ehrlich (ESC) tumor-bearing mice irradiation.. Fifty Swiss albino male mice were segmented into seven groups, including one control group and six Ehrlich induced tumors treated with ascorbic, ascorbic plus radiation, metformin, metformin plus radiation, and radiation only. Many tests, including behavioral, biochemical, immunohistochemistry, gene expression, DNA fragmentation, oxidative stress markers, and EPR, were performed to interrogate the modifying effects on tumor and liver tissues.. Remarkable apoptosis was found in metformin irradiated animals compared to irradiated ascorbic counterparts. The irradiated metformin mice showed the greatest reduction in PCNA. There was a significant reduction of DNA fragmentation in the liver tissues of the irradiated metformin group. Irradiated metformin and irradiated ascorbic acid animals showed a reduced signal of ERK as well as c-Fos genes. There was a tendency of metformin and metformin irradiated animals to reduce MDA levels in liver tissues. ESC-bearing mice treated with ascorbic or metformin showed an improvement in the spontaneous alternation percentage (SAP%) and improved short-term memory. There was also an improvement in long memory tests.. The study added more preclinical evidence on the utility of metformin in cancer treatment during radiotherapy. Metformin was shown to reduce lipid peroxidation in irradiated healthy tissues, increase tumor cytotoxicity, downregulate critical pathways involved in tumor progression and proliferation, and enhance tumor apoptosis. Controlled clinical trials using metformin are highly warranted.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Lipid Peroxidation; Metformin; Mice; Neoplasms

The purpose of the study was to obtain further in vivo data of antitumor effects and mechanisms triggered by juglone and Q7 in combination with ascorbate. The study was done using Ehrlich ascites tumor-bearing mice. Treatments were intraperitoneal every 24 h for 9 days. Control group was treated with excipient. Previous tests selected the doses of juglone and Q7 plus ascorbate (1 and 100 mg/kg, respectively). Samples of ascitic fluid were collected to evaluate carbonyl proteins, GSH and activity of antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase. Hypoxia inducible factor HIF-1α, GLUT1, proteins driving cell cycle (p53, p16 and cyclin A) and apoptosis (poly-ADP-polymerase PARP, Bax and Bcl-xL) were assessed by western blot. Tumor cells were categorized by the phase of cell cycle using flow cytometry and type of cell death using acridine orange/ethidium bromide. A glucose uptake assessment was performed by liquid scintillation using Ehrlich tumor cells cultured with (14)C-deoxyglucose. Treatments caused increased protein carbonylation and activity of antioxidant enzymes and decreased levels of GSH, HIF-1α, GLUT1 and glucose uptake in tumor cells. They also caused increased number of tumor cells in G1, p53 and p16 activation and decreased cyclin A, but only when combined with ascorbate. Apoptosis was induced mostly when treatments were done with ascorbate, causing PARP and Bax cleavage, and increased Bax/Bcl-xL ratio. Juglone and Q7 in combination with ascorbate caused inhibition of tumor progress in vivo by triggering apoptosis and cell cycle arrest associated with oxidative stress, suppression of HIF-1 and uncoupling of glycolytic metabolism.

Topics: Aminophenols; Animals; Antineoplastic Combined Chemotherapy Protocols; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Disease Progression; Male; Mice; Mice, Inbred BALB C; Naphthoquinones

New curcumin analogues have been synthesized and their antioxidant activities were investigated by measuring their free radical scavenging capacities. The in vitro and in vivo antitumor activities of the synthesized compounds on Ehrlich ascites carcinoma (EAC) cell line were evaluated. 4-(4-Chlorophenyl)-2-(5-ethyl-7-(4-methoxybenzylidene)-3-(4-methoxyphenyl)-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c] pyridin-2-yl)thiazole 7h showed excellent antineoplastic activity in both in vitro and in vivo studies more than that of tested compounds and reference drug, cisplatin. Different molecular modeling studies were performed, where docking of compound 7h into telomerase active site suggested that it could exert its antitumor potential by telomerase inhibition.

Topics: Animals; Antineoplastic Agents; Antioxidants; Carcinoma, Ehrlich Tumor; Cell Line, Tumor; Cell Proliferation; Cell Survival; Curcumin; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Humans; Mice; Models, Molecular; Molecular Structure; Neoplasms, Experimental; Structure-Activity Relationship

The aim of this study was to enhance the understanding of the antitumor mechanism of 1,4-naphthoquinones and ascorbate. Juglone, phenylaminonaphthoquinone-7, and 9 (Q7/Q9) were evaluated for effects on CT-DNA and DNA of cancer cells. Evaluations in MCF-7 cells are DNA damage, ROS levels, viability, and proliferation. Proteins from MCF-7 lysates were immunoblotted for verifying PARP integrity, γH2AX, and pAkt. Antitumor activity was measured in Ehrlich ascites carcinoma-bearing mice. The same markers of molecular toxicity were assessed in vivo. The naphthoquinones intercalate into CT-DNA and caused oxidative cleavage, which is increased in the presence of ascorbate. Treatments caused DNA damage and reduced viability and proliferation of MCF-7 cells. Effects were potentiated by ascorbate. No PARP cleavage was observed. Naphthoquinones, combined with ascorbate, caused phosphorylation of H2AX and inhibited pAkt. ROS were enhanced in MCF-7 cells, particularly by the juglone and Q7 plus ascorbate. Ehrlich carcinoma was inhibited by juglone, Q7, or Q9, but the potentiating effect of ascorbate was reproduced in vivo only in the cases of juglone and Q7, which caused up to 60% inhibition of tumor and the largest extension of survival. Juglone and Q7 plus ascorbate caused enhanced ROS and DNA damage and inhibited pAkt also in Ehrlich carcinoma cells.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA Damage; Histones; Humans; Male; MCF-7 Cells; Mice; Mice, Inbred BALB C; Naphthoquinones; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species

In this study, we evaluated the carcinostatic effects of combined ascorbic acid (AsA) and a capacitive-resistive electric transfer (CRet) hyperthermic apparatus-induced hyperthermic treatment on Ehrlich ascites tumor (EAT) cells.. EAT cells were exposed to various AsA (0-10 mM) concentrations for 1 h; they subsequently underwent CRet treatment for 15 min at 42 °C. Cell viability was assessed by the WST-8 assay 24 h after the combined treatment. Reactive oxygen species involvement was evaluated using catalase and tempol; caspase-3/7 activation was determined by their fluorescent substrates; cell proliferation were estimated by time-lapse observation. The effect on the cell cycle was analyzed by flow cytometry.. Combined AsA and CRet treatment synergistically suppressed cell viability compared with either treatment alone, and these synergistically carcinostatic effects were evident even at noncytotoxic concentrations of AsA alone (≤ 2 mM). The carcinostatic effects of combined AsA and CRet treatment were attenuated in a dose-dependent manner by catalase addition, but not by the superoxide anion radical scavenger tempol. Time-lapse observation revealed that combined AsA and CRet treatment activated caspase-3/7 at 10-24 h after treatment, accompanied by significant cell growth suppression. Cell cycle analysis revealed that the rate of sub-G1-phase (apoptotic) cells was drastically increased at 12 h and 24 h, and that the G2/M-phase cells gradually increased at 6-24 h after treatment.. These results indicate that combined AsA and CRet treatment synergistically inhibits EAT cell growth through G2/M arrest and apoptosis induction via H2O2 generation at lower AsA concentrations; this carcinostatic effect cannot be exerted by AsA alone.

Topics: Animals; Antineoplastic Agents; Apoptosis; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Combined Modality Therapy; Drug Screening Assays, Antitumor; Hyperthermia, Induced; Reactive Oxygen Species

The development of therapeutic strategies to attenuate chemotherapy toxicity represents an area of great interest in cancer research, and among them is nutritional therapy based on antioxidants. As research on this topic is still controversial and scarce, we aim to investigate the effects of antioxidant supplementation with vitamin C, vitamin E or pequi oil, a carotenoid-rich oil extracted from pequi (Caryocar brasiliense), on doxorubicin (DX)-induced oxidative damage to normal cells in Ehrlich solid tumor-bearing mice. Tumor weight and volume, histopathology, morphometry and immunohistochemistry were used to assess the treatments' efficacy in containing tumor aggressiveness and regression, while possible toxicity of treatments was assessed by animals' weight, morphological analysis of the heart, liver and kidneys, hemogram, and serum levels of total bilirubin, direct bilirubin, indirect bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (GGT), alkaline phosphatase, creatinine and urea. Although all the chemotherapeutic treatments increased internal necrosis area and reduced the positive Ki-67 cells compared to non-treated tumors, the treatments with pequi oil provided before tumor inoculation (PTDX) or in continuous and concurrent administration with doxorubicin (PTPDX) were more effective in containing tumor growth, besides increasing lymphocyte-dependent immunity and reducing the adverse side effects associated with DX-induced oxidative damage to normal cells, mainly the PTDX treatment. Vitamins C and E given before tumor inoculation and chemotherapy were not successful against doxorubicin-induced cardiotoxicity, besides increasing doxorubicin-induced nephrotoxicity, indicating that, at least for doxorubicin, pequi oil instead of vitamins C and E would be the best option to reduce its adverse effects.

Topics: Animals; Antibiotics, Antineoplastic; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Carotenoids; Doxorubicin; Female; Mice; Oxidative Stress; Plant Oils; Vitamin E

Magnetite nanoparticles (MNPs) have been widely used as contrast agents and have promising approaches in cancer treatment. In the present study we used Ehrlich solid carcinoma (ESC) bearing mice as a model to investigate MNPs antitumor activity, their effect on expression of p53 and p16 genes as an indicator for apoptotic induction in tumor tissues.. MNPs coated with ascorbic acid (size: 25.0±5.0 nm) were synthesized by co-precipitation method and characterized. Ehrlich mice model were treated with MNPs using 60 mg/Kg day by day for 14 injections; intratumorally (IT) or intraperitoneally (IP). Tumor size, pathological changes and iron content in tumor and normal muscle tissues were assessed. We also assessed changes in expression levels of p53 and p16 genes in addition to p53 protein level by immunohistochemistry.. Our results revealed that tumor growth was significantly reduced by IT and IP MNPs injection compared to untreated tumor. A significant increase in p53 and p16 mRNA expression was detected in Ehrlich solid tumors of IT and IP treated groups compared to untreated Ehrlich solid tumor. This increase was accompanied with increase in p53 protein expression. It is worth mentioning that no significant difference in expression of p53 and p16 could be detected between IT ESC and control group.. MNPs might be more effective in breast cancer treatment if injected intratumorally to be directed to the tumor tissues.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cyclin-Dependent Kinase Inhibitor p16; Drug Administration Schedule; Female; Gene Expression Regulation, Neoplastic; Injections, Intraperitoneal; Magnetite Nanoparticles; Mice; Neoplasm Proteins; Particle Size; Tumor Suppressor Protein p53

The aim of this study is to develop ascorbyl palmitate (ASP) loaded doxorubicin (DOX) pegylated liposomes and to evaluate their targeting potential to tumor. We have prepared conventional (DL), pegylated DOX liposomes with (SDL) and without ascorbyl palmitate (SDL-A). The vesicle size in all the formulations was within the range 105-120 nm and in vitro release studies in serum confirmed the stability of the liposomes. Biodistribution studies carried out in Ehrlich ascites tumor bearing mice indicate higher area under the curve for SDL and SDL-A liposomes compared to DL and plain drug solution. Drug targeting index assessed from tumor-to-serum concentration ratio and therapeutic availability of DOX in tumor tissue was also significantly higher for pegylated liposomes. In conclusion, biodistribution study reveals that the presence of ascorbyl palmitate alters the distribution pattern of liposomes and paves way for better drug targeting.

Topics: Animals; Antibiotics, Antineoplastic; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Doxorubicin; Drug Delivery Systems; Humans; Liposomes; Mice; Polyethylene Glycols

Strong evidence indicates that reactive oxygen species (ROS) play an important role in the initiation as well as the promotion phase of carcinogenesis. Studies support the role of ROS in cancer, in part, by showing that dietary antioxidants act as cancer-preventive agents. Although results are promising, the research on this topic is still controversial. Thus, the aim of this study was to investigate whether vitamins C, E and pequi oil can, individually, provide prevention and/or be used afterward as an adjuvant in cancer therapy. Ehrlich solid tumor-bearing mice received antioxidant as follows: before tumor inoculation, before and after tumor inoculation (continuous administration), and after tumor inoculation; morphometric analyses of tumor, genotoxicity and hematology were then carried out. Antioxidant administrations before tumor inoculation effectively inhibited its growth in the three experimental protocols, but administrations after the tumor's appearance accelerated tumor growth and favored metastases. Continuous administration of pequi oil inhibited the tumor's growth, while the same protocol with vitamins E and C accelerated it, favoring metastasis and increasing oxidative stress on erythrocytes. Except for continuous administration with vitamin E, the development of ascites tumor metastases was linked with increased inflammation. Results suggest that the efficiency and applicability of antioxidants in the medical clinic can depend not only on the nature of the antioxidant, the type and stage of cancer being treated and the prevailing oxygen partial pressure in the tissues, but also on the type of antioxidant therapy chosen.

Topics: Animals; Antioxidants; Ascorbic Acid; Blood Cell Count; Carcinoma, Ehrlich Tumor; Carotenoids; Comet Assay; Ericales; Female; Mice; Neoplasms; Plant Oils; Reactive Oxygen Species; Vitamin E

Previous in vivo studies from several laboratories had shown remarkable curative effect of methylglyoxal on cancer-bearing animals. In contrast, most of the recent in vitro studies have assigned a toxic role for methylglyoxal. The present study was initiated with the objective to resolve whether methylglyoxal is truly toxic in vivo and to reassess its therapeutic potential. Four species of animals, both rodent and non-rodent, were treated with different doses of methylglyoxal through oral, subcutaneous and intravenous routes. Acute (treatment for only 1 day) toxicity tests had been done with mouse and rat. These animals received 2, 1 and 0.3 g of methylglyoxal/kg of body weight in a day through oral, subcutaneous and intravenous routes respectively. Chronic (treatment for around a month) toxicity test had been done with mouse, rat, rabbit and dog. Mouse, rat and dog received 1, 0.3 and 0.1 g of methylglyoxal/kg of body weight in a day through oral, subcutaneous and intravenous routes respectively. Rabbit received 0.55, 0.3 and 0.1 g of methylglyoxal/kg of body weight in a day through oral, subcutaneous and intravenous routes respectively. It had been observed that methylglyoxal had no deleterious effect on the physical and behavioral pattern of the treated animals. Fertility and teratogenecity studies were done with rats that were subjected to chronic toxicity tests. It had been observed that these animals produced healthy litters indicating no damage of the reproductive systems as well as no deleterious effect on the offspring. Studies on several biochemical and hematological parameters of methylglyoxal-treated rats and dogs and histological studies of several organs of methylglyoxal-treated mouse were performed. These studies indicated that methylglyoxal had no apparent deleterious effect on some vital organs of these animals. A detailed pharmacokinetic study was done with mouse after oral administration of methylglyoxal. The effect of methylglyoxal alone and in combination with creatine and ascorbic acid on cancer-bearing animals had been investigated by measuring the increase in life span and tumor cell growth inhibition. The results indicated that anticancer effect of methylglyoxal was significantly augmented by ascorbic acid and further augmented by ascorbic acid and creatine. Nearly 80% of the animals treated with methylglyoxal plus ascorbic acid plus creatine were completely cured and devoid of any malignant cells within the peritoneal cavity.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Body Weight; Carcinoma, Ehrlich Tumor; Creatine; Dogs; Drug Synergism; Enzymes; Female; Fertility; Longevity; Male; Mice; Neoplasm Transplantation; Pyruvaldehyde; Rabbits; Rats; Reproduction; Species Specificity; Survival Analysis; Teratogens; Vitamins

Long-term administration of caffeine at a dose of 20 mg /kg/day p.o. suppressed the viability, oxygen consumption and [3H]-thymidine incorporation of Ehrlich ascites carcinoma (EAC) cells. Though no significant change in the levels of plasma and adrenal corticosterone as well as both total and reduced adrenal ascorbic acid were observed following long-term caffeine consumption, pretreatment of caffeine and continuation of its treatment in the course of development of EAC cells restored the EAC Cell-induced changes in both corticosterone and ascorbic acid levels to control values. These results, thus, suggest that caffeine may suppress the growth of EAC cells by modulating the adrenal ascorbate level as well as corticosterone status.

Topics: Adrenal Glands; Animals; Ascorbic Acid; Caffeine; Carcinoma, Ehrlich Tumor; Cell Division; Corticosterone; Female; Mice; Oxygen

Numerous natural and synthetic quinone compounds possess significant antitumor properties. Various mechanisms have been proposed to account for these properties, including scission and degradation of tumor cell DNA, intracellular "redox cycling" to cogenerate semiquinone free radicals and reactive oxygen intermediates, and the interaction of semiquinone radicals with tumor cell surface flavoenzymes. However, no evidence has been presented to explain adequately the preferential attack on tumor cells by semiquinone radicals, as opposed to normal cells. To address this question, a synergistic interaction was examined. A therapy consisting of a mixture of L-ascorbate and 2,6-dimethoxy-p-benzoquinone, was used for in vivo evaluation. BALB/c mice were depleted of functional T-lymphocytes by xenogeneic monoclonal antibody pretreatment, challenged with Ehrlich ascites tumor, and administered the semiquinone radical-generating therapy. Mice depleted of CD4+ T-lymphocytes responded with rapidly fatal tumor progression, with significantly decreased mean survival times over controls, whereas less severe responses were observed in mice devoid of CD8+ T-lymphocytes. Mice depleted of both T-lymphocyte subpopulations responded with uninhibited tumor growth and rapid mortalities. When tumor challenge occurred after therapy, tumor growth was significantly delayed in mice enriched for CD4+ T-lymphocytes, with demonstrable increases in mean survival time over controls. This reagent combination had no significant effect on T-lymphocyte profiles in secondary lymphoid organs. These data suggest a synergistic phenomenon of semiquinone radical-induced cytostasis coupled with T-lymphocyte helper activity for optimal tumor suppression.

Topics: Animals; Antibodies, Heterophile; Antibodies, Monoclonal; Antineoplastic Agents; Ascorbic Acid; Benzoquinones; Carcinoma, Ehrlich Tumor; CD4-Positive T-Lymphocytes; Cell Differentiation; Combined Modality Therapy; Female; Free Radicals; Lymphocyte Depletion; Male; Mice; Mice, Inbred BALB C; Rats; T-Lymphocytes

Effects of 6-O-palmitoyl ascorbate (ascorbate) developed to increase the antitumour activity of ascorbic acid on DNA synthesis and proliferation of Ehrlich ascites tumour cells were investigated. Treatment of the cells with the acylated ascorbate at 25-50 microM for 1 h resulted in no effect on DNA synthesis, assayed by pulse incorporation of [3H]thymidine after a culture period of 20 h, but led to 49%-87% enhanced DNA synthesis after 4 days, suggesting that long-term culture is required for promotion by ascorbate to occur. At a dose as high as 75 microM acylated ascorbate, however, cellular DNA synthesis was 64% inhibited after 20 h and 99% after 4 days. The results suggest that acylated ascorbate exhibits a dual action on DNA synthesis: promotion at low doses and inhibition at high doses, both of which are potentiated in a time-dependent manner. In contrast to the above-mentioned results at 37 degrees C, acylated ascorbate at 25-75 microM inhibited but did not promote DNA synthesis at 42 degrees C whatever the culture period. Similar results were exhibited when proliferation of cells cultured for a long period was investigated. At 37 degrees C, 50 microM acylated ascorbate increased the number of the cells to 3.6 times the control values after 8 days and to 1.9 times after 11 days; in contrast, a 75-microM dose decreased the cell number considerably. Combination with hyperthermia (42 degrees C) suppressed the increase and cell growth was completely inhibited at 75 microM.

Topics: Acylation; Animals; Antimutagenic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Count; Cell Division; Cell Survival; DNA Replication; DNA, Neoplasm; Female; Hot Temperature; Mice; Mice, Inbred ICR; Tumor Cells, Cultured

Ascorbic acid and its salts (AA) are preferentially toxic to tumor cells in vitro and in vivo. Given in high enough doses to maintain plasma concentrations above levels that have been shown to be toxic to tumor cells in vitro, AA has the potential to selectively kill tumor cells in a manner similar to other tumor cytotoxic chemotherapeutic agents. Most studies of AA and cancer to date have not utilized high enough doses of AA to maintain tumor cytotoxic plasma concentrations of AA. Data are presented which demonstrate the ability to sustain plasma levels of AA in humans above levels which are toxic to tumor cells in vitro and suggests the feasibility of using AA as a cytotoxic chemotherapeutic agent.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Line; Cell Survival; Humans; Infusions, Intravenous; Lung Neoplasms; Mice; Neoplasms; Tumor Cells, Cultured

Effects of hyperthermia and cell densities on inhibitory activity of ascorbic acid on DNA synthesis in Ehrlich ascites tumor cells were studied. When cells at a low density of 5 x 10(3)/ml were treated with 75 microM ascorbic acid for 1 h, DNA synthesis was inhibited after treatment at 37 degrees C and the inhibition was significantly enhanced at 42 degrees C. At a cell density as high as 1 x 10(5)/ml, however, inhibition did not occur at 37 degrees C or 42 degrees C. In contrast, dehydroascorbic acid was inactive even at a low cell density under similar conditions. Inhibitory effects of ascorbic acid on DNA synthesis were also markedly enhanced by treatment at 40 degrees C. DNA synthesis was not inhibited in the absence of the drug. Furthermore, mice transplanted with cells treated with a combination of 75 microM ascorbic acid and hyperthermia at 42 degrees C, considerably prolonged their survival time in comparison with untreated cells. Addition of ascorbic acid to hyperthermia is suggested to be an advantageous treatment for cancer.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Count; Cell Division; Dehydroascorbic Acid; DNA, Neoplasm; Female; Hyperthermia, Induced; Mice; Mice, Inbred ICR; Neoplasm Transplantation

Ehrlich Ascites Tumor (EAT) cells, compared to liver, were less susceptible to peroxidation (measured by the TBARS method) induced by Fe2+/ascorbate, ADP/Fe2+ and H2O2/Fe2+/ascorbate. Higher thiobarbituric acid reagent products TBARS levels were found with Fe2+/ascorbate or after ultrasonication induced peroxidation in lipids obtained from Ehrlich cells compared to EAT cell homogenate with the same lipid content. This suggests that non-lipid and structurally membrane antioxidants factors are of less importance for induction by Fe2+/ascorbate than by ultrasonication. The resistance to induced lipid peroxidation (LPO) in EAT cells is associated with the lower level of lipids, the lower double-bond index, the lower level of fatty acids reacting with TBA, as well as with the relatively higher level of alpha-tocopherol per mg lipid in the EAT cells as compared to the liver.

Topics: Adenosine Diphosphate; Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Chromatography, High Pressure Liquid; Fatty Acids; Ferric Compounds; Hydrogen Peroxide; In Vitro Techniques; Lipid Peroxidation; Lipids; Liver; Male; Mice; Mice, Inbred BALB C; Oxidative Stress; Rats; Thiobarbituric Acid Reactive Substances; Ultrasonics; Vitamin E

A combination of dehydroascorbic acid and hydroxycobalamin (vitamin B-12) inhibited mitoses of tumors in mice. The present study was performed to test the effect of these vitamins on the survival of mice bearing carcinomas and leukemias. In each assay 40 mice received 0.1 mL ip tumor cells (x10(5)). After 24 h, 20 mice were injected with 0.2 mL (0.4 g/kg body wt) of the vitamins daily for 10 d. All controls died by day 19, but greater than 50% of the treated mice were alive after 60 d. In vitro findings revealed inhibition of mitoses in L1210 leukemia cells, but not in normal L929 cells. In recent research with cobalt-ascorbate plus vitamin C, we demonstrated that when B-12 is combined with vitamin C, the cobalt nucleus of B-12 attaches to a carbon on vitamin C, forming cobalt ascorbate. Tests proved that cobalt ascorbate plus vitamin C also inhibited tumor cells.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Dehydroascorbic Acid; Drug Combinations; Female; Leukemia, Experimental; Mice; Mice, Inbred ICR; Neoplasm Transplantation; Survival Analysis; Vitamin B 12

Adriamycin (ADR) is effective against a wide range of human neoplasms. However, its clinical use is compromised by serious cardiac toxicity, possibly through induction of peroxidation in cardiac lipids. Ascorbic acid, a potent antioxidant, was examined for effect in reducing ADR toxicity in mice and guinea pigs. Ascorbic acid had no effect on the antitumor activity of ADR in mice inoculated with leukemia L1210 or Ehrlich ascites carcinoma, but it significantly prolonged the life of animals treated with ADR. ADR elevated lipid peroxide levels in mouse heart, and ascorbic acid prevented the elevation. The significant prevention of ADR-induced cardiomyopathy in guinea pigs by ascorbic acid was proved by electron microscopy. Ascorbic acid and the derivatives may delay general toxicity of ADR and also prevent the cardiac toxicity. The results also suggest the clinical efficacy of the combined treatment of ADR and ascorbic acid or the derivatives.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cardiomyopathies; Doxorubicin; Guinea Pigs; Leukemia, Experimental; Lipid Peroxides; Mice; Mice, Inbred Strains; Myocardium; Neoplasm Transplantation

The effect of methylglyoxal (MG), ascorbic acid and lactaldehyde has been tested on the in vitro respiration of Ehrlich ascites carcinoma (EAC) cells and several normal and malignant human tissues. Methylglyoxal inhibited the respiration of each type of malignant cell and tissue tested, but it had practically no inhibitory effect on the respiration of any of the normal cells and tissues. Ascorbic acid exhibited a synergistic effect with MG in inhibiting the respiration of all the neoplastic cells. In the presence of lactaldehyde, a catabolite of MG, the inhibitory effect of MG on the respiration of tumor cells was significantly reduced. Lactaldehyde can exert a similar protective effect on the loss of viability and transplantability of MG-treated EAC cells.

Topics: Aldehydes; Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Survival; Female; Humans; In Vitro Techniques; Leukemia; Mice; Neoplasms; Oxygen Consumption; Pyruvaldehyde; Uterus

To examine the roles of oxygen free radicals in the inhibition of tumor cell proliferation, we have used disulfiram (DS), a metal-chelator, to inactivate superoxide dismutase and ascorbic acid (AsA) to inhibit catalase. Simultaneous addition of DS and AsA to Meth A tumor cells or Ehrlich ascites tumor cells induced marked inhibition of the cell proliferation assessed by [3H]thymidine uptake and trypan blue dye exclusion method. Similar augmented inhibition of Meth A tumor cell proliferation was observed when the cells were pretreated with DS and AsA. However, the addition of catalase (2000 u/ml) nullified the augmentation of anti-proliferative effect which can be induced in the combined use of DS and AsA. These results suggest that the steady-state increase of intracellular oxygen free radicals within tumor cells could be induced in the combined use of DS and AsA.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Catalase; Cell Division; Disulfiram; Free Radicals; Mice; Neoplasms, Experimental; Oxygen; Tumor Cells, Cultured

We studied the effects of 6-0-acylated derivatives of ascorbate on ornithine decarboxylase (ODC, E.C.4.1.1.17) activity and the ODC-mRNA level in Ehrlich ascites cells. These derivatives are known to inhibit cell growth. When cells grown to the stationary phase were diluted and stimulated with fresh medium containing 10% dialyzed fetal calf serum, the ODC activity increased rapidly and transiently with a peak at 4 hr. Ascorbate or 2,6-dipalmitoyl ascorbate had little or no effect on the induction of ODC, but 6-0-palmitoyl ascorbate (6P) suppressed the enzyme activity in a time- and dose-dependent way. 6-0-Stearoyl ascorbate had a similar effect. The amount of ODC-mRNA formed after growth stimulation was not affected by 6P. These results indicate that the treatment of Ehrlich ascites tumor cells with 6P caused dose-dependent suppression of ODC induction post-transcriptionally.

Topics: Acetylation; Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Enzyme Induction; Female; Mice; Mice, Inbred ICR; Ornithine Decarboxylase; RNA, Messenger; Tumor Cells, Cultured

Lipid peroxidation intensity is compared in Ehrlich Ascites Cell and in liver mitochondria, prepared from tumor bearing mice. Malondialdehyde formation is negligible in intact ascites tumour mitochondria, but it is significantly increased in permeabilised mitochondria and in isolated mitochondrial membranes. We suggest that the resistance against oxidative stress is a consequence of efficient protective mechanisms operating in the intact tumour mitochondria and the low level of polyunsaturated fatty acids under these circumstances cannot be the rate limiting factor in lipid peroxidation. Succinate, an effective inhibitor of mitochondrial lipid peroxidation in liver, cannot determine malondialdehyde formation in ascites tumour mitochondria.

Topics: Adenosine Diphosphate; Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Fatty Acids, Unsaturated; Intracellular Membranes; Iron; Lipid Peroxides; Mice; Mitochondria; Mitochondria, Liver; NADP; Permeability; Tumor Cells, Cultured

Glycylglycylhistidine (GGH) was synthesized using mixed anhydride method, and Cu(II): GGH = 1:1 complex was identified using UV, ESR, CD, ORD and FAB/MS technique. The oxidation of ascorbate catalyzed by cupric ion in RPMI 1640 medium (pH 7.40) was studied. The activation energy E = 39.2 kJ/mol. The addition of GGH inhibited the oxidation of ascorbate catalyzed by cupric ion. The investigations with ESR and fluorimetry indicate that there are Cu(I), ascorbate radical (AH), O2-., H2O2 and .OH during the oxidation.

Topics: Animals; Ascitic Fluid; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Copper; Mice; Oligopeptides; Oxidation-Reduction

Previous electron spin resonance studies have demonstrated that the decay of ascorbyl plus semiquinone radicals, produced in an aqueous mixture of ascorbate and 2,6-dimethoxy-p-quinone, is accelerated by ascites cells. This effect was concluded to involve a sulfhydryl-containing NAD(P)H-enzyme, and work on cultured cell lines showed that on neoplastic transformation the activity against the radicals was increased. We show here that at least three disulfide-oxidoreductases are able to quench the radicals in a similar way to that of viable cells. Glutathione reductase (EC 1.6.4.2) in the presence of NADPH and oxidised glutathione, and dihydrolipoamide dehydrogenase (EC 1.8.1.4) with NADH and lipoamide, are found to accelerate the radical decay by reducing the quinone or semiquinone. DT-diaphorase (EC 1.6.99.2) in the presence of NAD(P)H can also achieve this by reducing the quinone directly. Lipoamide dehydrogenase and glutathione reductase are also capable of reducing nitroxide spin labels, a finding considered of relevance to the reported reduction of such spin labels by neuroblastoma cells.

Topics: Animals; Ascorbic Acid; Benzoquinones; Carcinoma, Ehrlich Tumor; Electron Spin Resonance Spectroscopy; Free Radicals; Kinetics; Oxidoreductases; Quinones

Orders of susceptibility of Ehrlich ascites tumor to L-ascorbic acid (Asc), its 6-stearoyl (6S), 6-palmitoyl (6P) and 2,6-dipalmitoyl (DP) derivatives were assessed in vitro and in vivo: 6P (a 50% growth inhibitory concentration (IC50) for cultured cells, 12 microM; an increased life-span of treated mice, 283%) greater than 6S (61 microM; 240%) much greater than Asc (430 microM; 122%) greater than or equal to DP (greater than 200 microM; 89%), indicating that the enhanced susceptibility was due to acyl moiety substituted at C6-hydroxyl group of Asc, but was retracted by further substitution at C2-hydroxyl group. Equimolar mixture of Asc and palmitic acid, stearic acid or their methyl esters was much less cytotoxic than 6P or 6S. Thus the enhanced susceptibility was not primarily due to an additive cytotoxic effect of ascorbyl and acyl moieties, but to a balanced hydrophobicity introduced into the molecule by a poorly cytotoxic acyl moiety.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cells, Cultured; Female; Mice; Mice, Inbred Strains; Solubility; Structure-Activity Relationship

The rate of scavenging by Ehrlich ascites cells of anionic ascorbyl and 2,6-dimethoxy-p-semiquinone free radicals has been investigated by electron spin resonance spectroscopy both for viable cells and for subcellular fractions obtained by differential centrifugation. The scavenging activity is concluded to be associated with an NAD(P)H enzyme containing an active sulfhydryl group. Attempts to identify the enzyme with the reported properties of either semi-dehydro-ascorbate reductase or DT-diaphorase have not been successful. The overall free-radical scavenging activity for viable cells is dextrose dependent and is controlled by the coulombic barrier associated with the cell-surface charge. The cytotoxicity of the mixture of ascorbic acid with 2,6-dimethoxy-p-benzoquinone is concluded to result from a loss of NAD(P)H reducing power in the cells.

Topics: Animals; Ascorbic Acid; Benzoquinones; Carcinoma, Ehrlich Tumor; Female; Free Radicals; Magnetic Resonance Spectroscopy; Mice; NAD; Quinones; Sulfhydryl Compounds; Surface Properties

The rate of quenching by Ehrlich ascites cells of anionic 2,6-dimethoxy-p-semiquinone and ascorbyl free radicals is investigated as a function of cell concentration, the blocking of cell-surface sulfhydryl groups by N-ethylmaleimide, and the reduction of cell-surface charge by neuraminidase. The rate of quenching is found to be proportional to cell viability and to the number of free cell-surface sulfhydryl groups. The enzymatic action of neuraminidase results in an increase of the free radical quenching rate, indicating that this rate can be used as a probe of cell-surface charge. Measurements as a function of the ionic strength of the suspending electrolyte gave a value of -1.22 microC X cm-2 for the charge density at the ascites cell surface. This is equivalent to a surface membrane potential of -14 mV for a 150 mM NaCl electrolyte and is a value in good agreement with published electrophoresis data.

Topics: Animals; Ascorbic Acid; Benzoquinones; Carcinoma, Ehrlich Tumor; Cell Membrane; Electric Conductivity; Ethylmaleimide; Free Radicals; Kinetics; Mice; Quinones; Surface Properties; Thermodynamics

Ascorbate in an aqueous solution is easily oxidized by molecular oxygen in the presence of cupric ion, thus producing reactive oxygen species and exhibiting cytotoxicity. In order to increase the antitumor activity of ascorbate, we used the innocuous form of cupric ion complexed with glycylglycylhistidine, a tripeptide designed to mimic the specific Cu(II) transport site of albumin molecule. Although this square planar copper:glycylglycylhistidine complex did not significantly oxidize ascorbate at pH 7.4, it killed Ehrlich ascites tumor cells in vitro in a high concentration of ascorbate. The injections of large doses of ascorbate together with copper: glycylglycylhistidine prolonged the life span of mice inoculated i.p. with Ehrlich tumor cells. The target specificity against tumor cells was primarily attributable to their high peptide-cleaving activity.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Survival; Copper; Drug Synergism; Electron Spin Resonance Spectroscopy; Kinetics; Mice; Oligopeptides; Oxidation-Reduction

The activation of Ca2+ -dependent K+ channel by propranolol or by ascorbate-phenazine methosulphate stimulates Na+ -dependent transport of alpha-aminoisobutyric acid. This stimulation arises from a membrane hyperpolarization due to the specific increase of membrane K+ conductance. The same treatment does not modify the Na+ -independent uptake of the norbornane amino acid.

Topics: Amino Acids; Aminoisobutyric Acids; Animals; Ascorbic Acid; Biological Transport; Calcium; Carcinoma, Ehrlich Tumor; Ion Channels; Kinetics; Methylphenazonium Methosulfate; Mice; Potassium; Propranolol; Sodium

Swiss mice drank either distilled water or 0.1% ascorbic acid in distilled water for one week prior to and during the experiments. Solid tumors were induced by injecting Ehrlich ascites tumor cells i.m. into the hind limb of Swiss male and female mice. It was found that the tumor growth was significantly faster in the mice that were drinking distilled water. Beginning two days after tumor cell injection, the tumor bearing limbs were irradiated every 24 h as follows: a) 6 exposures of 400 R, 500 R, 600 R, or 700 R each, b) 10 exposures of 400 R each, and c) 11 exposures of 400 R each. Our results indicated that when 6 exposures of 700 R each were given every 24 h to mice drinking distilled water, about 80-85% tumor control was achieved; the percent tumor cure was even better in mice drinking ascorbic acid in water than in mice drinking water.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Mice; Time Factors

The transplantable murine ascites tumors, P388 leukemia and Ehrlich carcinoma, demonstrated complete inhibition of mitotic activity after treatment with dehydroascorbic acid in mice. Citric acid at the same pH value (2.4), however, showed no diminution of mitoses. Microscopic examination of the stained ascites exudate taken from the mice treated with 10 mg dehydroascorbic acid revealed few tumor cells and a pronounced increase in white blood cells, whereas the ascites tumor exposed to citric acid appeared normal.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Division; Citrates; Citric Acid; Dehydroascorbic Acid; Leukemia P388; Leukemia, Experimental; Leukocyte Count; Mice; Mitosis

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Fractionation; Cell Line; Drug Interactions; Drug Resistance; Fluorouracil; Isotope Labeling; Mice; RNA, Neoplasm; Tritium

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Drug Therapy, Combination; Leukemia P388; Leukemia, Experimental; Mice; Mice, Inbred Strains; Vitamin B 12

Immunological studies are reported showing that ascorbic acid, like selected sulfhydryl inhibitors, can induce immunity against some cancers in mice. Accompanying this immunizing action are changes in the surface structure of the cancer cells, as revealed by scanning electron microscopy. Electron spin resonance measurements show that the ascorbate anion free radical is readily produced in oxygenated cancer tissue and that this radical can react with sulfhydryl groups which are free radical scavengers. It is proposed that ascorbate acts as an effective thiolprive in oxygenated cancer tissues. This action is thought to lead to the observed changes in the cancer cell surface structure and to the concomitant immunological response.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Line; Cell Membrane; Electron Spin Resonance Spectroscopy; Free Radicals; Mesothelioma; Mice; Microscopy, Electron, Scanning; Microvilli; Sarcoma 180; Sulfhydryl Reagents

Topics: Acetals; Aldehydes; Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Drug Combinations; Male; Mice; Mice, Inbred CBA; Mitotic Index; Neoplasm Transplantation; Pyruvaldehyde

The addition of 5 mM ascorbate plus 0.09 mM phenazine methosulfate stimulated 2- to 3-fold the initial rate of 2-aminoisobutyric acid transport into Ehrlich cells. This was observed under the conditions in which glycolysis and mitochondrial electron transport were blocked by iodoacetate and KCN, and the cellular ATP level was maintained below 0.1 mM. Proton conductors, carbonylcyanide m-chlorophenylhydrazone and SF6847 did not affect the stimulation of 2-aminoisobutyric acid uptake caused by ascorbate plus phenazine methosulfate. Ascorbate was replaced by NADH but not by NADPH, and phenazine methosulfate was the only effective acceptor in stimulating 2-aminoisobutyric acid uptake. The stimulating effect of ascorbate plus phenazine methosulfate was due to an increase in the V value for 2-aminoisobutyric acid but not in the Km value. This effect required the presence of an Na+ gradient and was accompanied by an increase in 22Na+ influx. The molar ratio of 2-aminoisobutyric acid to Na+ uptake enhanced by ascorbate plus phenazine methosulfate was calculated to be 1 : 1. Quinacrine, an inhibitor of NADH oxidoreductase in the plasma membrane, inhibited both the enhanced rate of 2-aminoisobutyric acid and Na+ transport without affecting the basal transport activity. The stimulatory effect of ascorbate plus phenazine methosulfate was also observed with other amino acids, alanine, glycine, proline and cycloleucine which are known to be transported via an Na+-dependent system but not with leucine and threonine. These results suggest that a redox system in the plasma membrane participates in energy coupling for amino acid transport by increasing the rate of cotransport with Na+.

Topics: Adenosine Triphosphate; Amino Acids; Aminoisobutyric Acids; Animals; Ascorbic Acid; Biological Transport; Carcinoma, Ehrlich Tumor; Cell Membrane; Electron Transport; Female; Kinetics; Methylphenazonium Methosulfate; Mice; Mice, Inbred ICR; Mitochondria; Potassium; Quinacrine; Sodium

Transport of methotrexate in mammalian cells is a complex process. Although the drug is pumped uphill into cells, metabolic poisons enhance influx and transmembrane gradients for this agent. Structurally unrelated inorganic and organic anions nonspecifically depress these parameters in a variety of tumor cells. It has been suggested that cell cyclic adenosine 3':5'-Monophosphate (cyclic AMP) plays a regulatory role in the transport of this agent. To evaluate this further, a number of different experimental approaches were used to analyze the relationship between methotrexate transport and cell cyclic AMP in the Ehrlich ascites tumor. The following results indicate that for the Ehrlich ascites tumor, at least, there is no evidence for a regulatory role for cyclic AMP in the transport of methotrexate. (a) A marked increase in cell cyclic AMP by cholera-toxin or reduction in cyclic AMP by ascorbate was unaccompanied by changes in methotrexate influx. (b) Instantaneous and constant inhibition of methotrexate influx by isobutylmethylxanthine was temporally dissociated from the slower rise in cell cyclic AMP that was induced by this agent. (c) Although isobutylmethylxanthine and dibutyryl cyclic AMP augment cell cyclic AMP and decrease methotrexate influx, they have different effects on efflux and net transport of methotrexate. Isobutylmethylxanthine stimulates net methotrexate uptake and slows methotrexate efflux but dibutyryl cyclic AMP depresses net methotrexate uptake without an effect on methotrexate efflux. (d) Azide markedly stimulates methotrexate influx and net transport without a change in cell cyclic AMP. (d) Dinitrophenol inhibits methotrexate influx and augments net methotrexate accumulation but does not alter cell cyclic AMP.

Topics: 1-Methyl-3-isobutylxanthine; Animals; Ascorbic Acid; Azides; Biological Transport, Active; Carcinoma, Ehrlich Tumor; Cell Membrane; Cells, Cultured; Cholera Toxin; Cyclic AMP; Methotrexate; Mice; Stimulation, Chemical

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Membrane; Connective Tissue; Male; Mice; Microscopy, Electron

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cyclic AMP; Glucose; Hot Temperature; In Vitro Techniques; Lactates; Male; Mice; Pyruvates

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Citrates; Glucose; Hyperthermia, Induced; In Vitro Techniques; Kidney; Male; Mice; Pyruvates; Spleen

The mitotic activity of the transplantable mouse tumors, Sarcoma 37, Krebs-2, and Ehrlich carcinomas, in the ascites form, were inhibited after treatment with a mixture of vitamins C and B12 with no apparent toxic side effects. These vitamins when administered alone, at the same dosage, did not seem to have any apparent effect on mitosis or the morphology of the cells studied. Microscopic examination of the stained ascites fluid taken from the mice treated with the vitamin mixture showed few tumor cells, and these in various stages of disintegration. Also, an increase in lymphocytes, monocytes and neutrophils were noticed; however, later in the experiment, no tumor cells could be found and monocytes and macrophages were abundant.

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Carcinoma, Krebs 2; Depression, Chemical; Female; Mice; Mitosis; Sarcoma 37; Time Factors; Vitamin B 12

D-Isoascorbic acid, an isomer of vitamin C, and betaine hydrate (quaternary amine) were found to inhibit mitoses of sarcoma 37, Ehrlich carcinoma, and L1210 leukemia cells in vitro. However, the combined effect of these compounds produced a greater inhibitory activity than when either was administered individually.

Topics: Animals; Ascorbic Acid; Betaine; Carcinoma, Ehrlich Tumor; Cell Line; Drug Therapy, Combination; Leukemia L1210; Mice; Mitosis; Neoplasms, Experimental; Sarcoma 37

Dehydroascorbate, an electron affinic metabolite of vitamin C, sensitized Ehrlich ascites tumor cells, in vivo, to radiation and was selectively toxic to V79 Chinese hamster lung cells under hypoxic conditions (without radiation). The radiosensitization may involve both the electron affinic nature of dehydroascorbate as well as its ability to oxidize the intracellular NAD(P)H and non-protein sulfhydryl. Dehydroascorbate's oxidation of NAD(P)H required higher concentrations than other sulfhydryl oxidants such as N-ethylmaleimide and diamide. The oxidation of NAD(P)H by dehydroascorbate could be reversed by glucose. Hypoxic cell radiosensitization of V79 cells in tissue culture by dehydroascorbate could not be easily demonstrated because of the rapid breakdown and appreciable cytotoxicity of the drug at high concentration. The cytotoxicity was found to occur with both high and low densities of V79 cells. With low cell densities small amounts of oxygen did not reduce the cytotoxicity of dehydroascorbate, but virtually eliminated the cytotoxicity of nitroaromatic electron affinic compounds (metronidazole and Ro-07-0582). The cytotoxicity to dense cell suspensions was found to depend upon the type of buffer included in the reaction medium. The maximum cytotoxicity was obtained in buffer free saline. The reduced form of dehydroascorbate, vitamin C, was found to be toxic only under aerobic conditions. The aerobic cytotoxicity could be prevented by the addition of catalase to the growth medium or by an increase in cell density, suggesting it was caused entirely by the production of H2O2 from the oxidation of vitamin C.

Topics: Aerobiosis; Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cell Line; Cell Survival; Cricetinae; Dehydroascorbic Acid; Diamide; Ethylmaleimide; In Vitro Techniques; Mice; NADP; Radiation-Sensitizing Agents; Sulfhydryl Compounds

1. The interaction of intact Ehrlich ascites-tumour cells with Ca2+ at 37 degrees C consists of Ca2+ uptake followed by efflux from the cells. Under optimum conditions, two or three cycles of uptake and efflux are observed in the first 15 min after Ca2+ addition. 2. The respiratory substrates malate, succinate and ascorbate plus p-phenylenediamine support Ca2+ uptake. Ca2+ uptake at 37 degrees C is sensitive to the respiratory inhibitors rotenone and antimycin A when appropriate substrates are present. Ca2+ uptake and retention are inhibited by the uncoupler S-13. 3. Increasing extracellular Pi (12 to 30 mM) stimulates uncoupler-sensitive Ca2+ uptake, which reaches a maximum extent of 15 nmol/mg of protein when supported by succinate respiration. Ca2+ efflux is partially inhibited at 30 mM-Pi. 4. Optimum Ca2+ uptake occurs in the presence of succinate and Pi, suggesting that availability of substrate and Pi are rate-limiting. K. Ca2+ uptake occurs at 4 degrees C and is sensitive to uncouplers and oligomycin. Ca2+ efflux at this temperature is minimal. These data are consistent with a model in which passive diffusion of Ca2+ through the plasma membrane is followed by active uptake by the mitochondria. Ca2+ uptake is supported by substrates entering respiration at all three energy-coupling sites. Ca2+ efflux appears to be an active process with a high temperature coefficient.

Topics: Animals; Ascorbic Acid; Biological Transport; Calcium; Carcinoma, Ehrlich Tumor; Energy Metabolism; In Vitro Techniques; Kinetics; Malonates; Mice; Mitochondria; Oligomycins; Phosphates; Succinates; Temperature; Uncoupling Agents

Topics: Adenosine Triphosphate; Amino Acids; Animals; Ascorbic Acid; Bacteria; Biological Transport, Active; Carcinoma, Ehrlich Tumor; Cell Line; Cell Membrane; Hydrogen-Ion Concentration; Membrane Potentials; Mitochondria; NADH, NADPH Oxidoreductases; Oxidation-Reduction; Phenazines; Potassium; Pyruvates; Quinacrine; Sodium; Uncoupling Agents

Derivatives of ascorbic acid were synthesized, and the studies were made on their effects in Ehrlich ascites carcinoma cells, in regard to the inhibition and the prolongation of survival time as well as on the morphological degeneration in HeLa cells. In a model infection study carried out by using tetraacetyl-bis-dehydroascorbic acid in dd mice infected with Ehrlich cells, it was proved that the prolongation of survival time was nearly double in comparison to the control group mice. Also, it was noted that hypertrophy due to abdominal dropsy and body weight were reduced much more than in the control group. From these results, the inhibiting effect of tetraacetyl-bis-dehydroascorbic acid was confirmed. While in the case of DHA and other derivatives, almost no inhibition and prolongation of survival time were observed. As for HeLa cells in a tissue culture, tetraacetyl-bis-DHA, in a dosage of 125-250 mug/ml, demonstrated definitely its morphological degeration. After 125 mug/ml of tetraacetyl-bis-DHA was added to a tissue culture solution of HeLa cells, the cells were washed and recultured. No growth of the cells was observed. Consequently, this substance was confirmed to be anti-HeLa substance with a low toxicity.

Topics: Animals; Ascorbic Acid; Body Weight; Carcinoma, Ehrlich Tumor; Dehydroascorbic Acid; HeLa Cells; Humans; Lethal Dose 50; Mice

Topics: Animals; Ascorbic Acid; Benzopyrenes; Carcinoma; Carcinoma, Ehrlich Tumor; Dipyridamole; Female; Glucose; Hyperbaric Oxygenation; Male; Methods; Mice; Neoplasms, Experimental; Rats; Sarcoma, Experimental; Sarcoma, Yoshida; Vitamin A; Vitamin B Complex

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Epinephrine; Flavonoids; Lymphoma, Non-Hodgkin; Mice; Neoplasm Transplantation; Neoplasms, Experimental; Norepinephrine; Rats; Sarcoma 180

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Chlorides; Colorimetry; Evaluation Studies as Topic; In Vitro Techniques; Iodoacetates; Mice; Neoplasms; Succinate Dehydrogenase; Tetrazolium Salts

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Catalase; Drug Synergism; Glucose; Hydrogen Peroxide; Mice; Oxygen; Triazoles; Vitamin K

Topics: Animals; Antigens; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Copper; In Vitro Techniques; Mice; Schistosoma; Yersinia pestis

Topics: Aniline Compounds; Animals; Antimycin A; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Cytochromes; Electron Transport; Hydroxybutyrates; In Vitro Techniques; Liver; Mitochondria; Oxidative Phosphorylation; Phenazines; Rats; Spectrophotometry; Succinates; Vitamin K

Topics: Alkylating Agents; Animals; Ascorbic Acid; Azaguanine; Carcinoma, Ehrlich Tumor; Chelating Agents; Glucuronates; Hydro-Lyases; Intestinal Absorption; Iron; Mercaptopurine; Mice; Porphyrins; Quinones; Thiotepa

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Liver; Liver Neoplasms; Lymphoma; Lymphoma, Non-Hodgkin; Metabolism; Mice; Microsomes; Microsomes, Liver; Neoplasms; Neoplasms, Experimental; Oxidoreductases; Research