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T Giraldi

Publications and source records attributed to T Giraldi.

At least 55 records · Page 3Linked to original sources
PubMed1984

Effects of dimethyltriazenes on in vitro Lewis lung carcinoma tumor lines with different metastatic capacity.

The effects of a selective antimetastatic agent: the aryldimethyltriazene derivative 1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) have been examined on two in vitro tumor cell lines derived from lung metastases of Lewis lung carcinoma. These stabilized in vitro tumor cell lines named C108 and BC215 have been reported to differ in their metastatic potential evaluated as lung colony forming ability and as the number of spontaneous metastases produced after intramuscular implant of tumor cells. The cytotoxic effect of DM-COOK in vitro was also compared with the one demonstrated by the structure-related compound 4-(3,3-dimethyl-1-triazeno)imidazole-5- carboxamide (DTIC) on the same variant lines. Survival curves show a different chemosensitivity of the two in vitro lines to the DM-COOK treatment, whereas no differences were detected between C108 and BC215 after exposure to DTIC. Moreover, DM-COOK and DTIC exhibit different trends of cell killing, implying different mechanisms of action for the two drugs. Results are discussed in view of the selective in vitro action of the aryldimethyltriazene derivative DM-COOK on cells which express a high metastatic potential.

Animals↗
PubMed1984

Antimetastatic action and hematological toxicity of p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt and 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide used as prophylactic adjuvants to surgical tumor removal in mice bearing B16 melanoma.

The treatment of mice bearing i.m. B16 melanoma with equitoxic dosages of the clinically used 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC) and of its benzenoid water-soluble analogue p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) prior to surgical tumor removal results in a remarkable proportion of cures, even when the treatment is started on already palpable tumors for which surgery alone is ineffective. The survival time of mice which are not cured is also significantly increased with DM-COOK. At the same time, DM-COOK does not affect artificial metastases or spontaneous metastases in mice undergoing surgery and treated with DM-COOK postoperatively. Inhibition of i.m. tumor growth in surgical experiments, and of s.c. tumors in mice not treated with surgery, is significant, although not as pronounced as is necessary to obtain significant prolongation of the life span of the host; the survival time of mice with s.c. tumors treated with both drugs is indeed not significantly increased. DM-COOK thus appears to exert selective antimetastatic effects, unrelated to cytotoxicity for tumor cells, against B16 melanoma in addition to those reported for Lewis lung carcinoma and M5 ovarian reticular cell sarcoma; its therapeutic usefulness is evidenced in adjuvant surgical experiments. DM-COOK, unlike DTIC, is devoid of hematological toxicity for the host. Since, in leukemic mice, it is at least as active as DTIC in increasing the life span of the treated animals, it appears to be an advantageous substitute for DTIC that could undergo preliminary clinical trial.

Animals↗
PubMed1983

Effects of isomeric aryldimethyltriazenes on Lewis lung carcinoma growth and metastases in mice.

The effects of the ortho and para isomers of aryldimethyltriazeno carboxylic and benzensulfonic acids and amides have been examined in mice bearing subcutaneous Lewis lung carcinoma. The toxicity of these compounds varies widely and does not correlate with the effects on tumor progression. The growth of subcutaneous primary tumor is unaffected or only marginally inhibited by all the tested compounds, while a marked depression in the formation of spontaneous lung metastasis is observed, with the exception of the sodium salt of the ortho benzensulfonic acid. The compounds showing the greatest activity on metastasis are the hydrosoluble salts of the ortho and para carboxylic acid and the para sulfonamido derivative, indicating that, in addition to the activity reported for the potassium salt of the para carboxylic acid, also its ortho isomer and the para sulfonamido derivative possess selective and pronounced antimetastatic effects. No correlation can be found between the reported effects on tumor progression and physicochemical parameters of the triazenes tested.

Animals↗
PubMed1983

Antitumor effects of rhodium(I), iridium(I) and ruthenium(II) complexes in comparison with cis-dichlorodiammino platinum(II) in mice bearing Lewis lung carcinoma.

The effects of square planar rhodium, [RhacacCOD]o and iridium, [IracacCOD]o complexes and of octahedral ruthenium, [cis-RuCl2 (DMSO)4]o complex have been examined in comparison with cis-dichlorodiammino platinum(II) (cis-PDD). The toxicity in BDF1 mice varies widely and decreasing LD50-values, ranging from 0.94 mg/kg to 1000 mg/kg, have been obtained for cis-PDD, [RhacacCOD]o, [IracacCOD]o and [cis-RuCl2(DMSO)4]o, respectively. All the tested complexes similarly inhibit the growth of subcutaneous Lewis lung carcinoma and the development of spontaneous as well as of artificial metastases, with the exception of [IracacCOD]o which is inactive on metastases. The antitumor activity of [RhacacCOD]o and [cis-RuCl2(DMSO)4]o appears interesting, since it is of the same magnitude as that of cis-PDD, considering also that they were found to be only marginally nephrotoxic.

Animals↗
PubMed1983

Immunotherapy of Lewis lung carcinoma with hydrosoluble peptidoglycan monomer (PGM).

The water-soluble peptidoglycan monomer (PGM) isolated from the culture fluid of Brevibacterium divaricatum, which has immunostimulating activity, has been examined for its antitumor effects in C57BL mice bearing Lewis lung carcinoma. The formation of spontaneous lung metastases from SC tumor implants is significantly inhibited. The growth of SC primary tumors, including advanced ones, is also significantly inhibited, though to a less pronounced extent than the growth of metastases. The effects on metastases are evident with all treatment schedules used, whereas those on SC primary tumors are treatment schedule-dependent. The treatment with PGM was found to be therapeutically useful when combined with surgical removal of IM implants; in conditions where a single post-operative treatment was ineffective, combined post-operative and immediately pre-operative administration of PGM significantly increased (by 40%) the survival time of treated animals over that of controls undergoing surgery only.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1983

Antitumor effects of GANU and other nitrosourea derivatives against transplantable leukemias and solid tumors in mice.

The antitumor effects of GANU have been examined in a panel of mouse tumors for which data appear to be lacking in the literature. GANU has significant activity against P388 leukemia and TLX5 lymphoma, and also against the solid tumors B16 melanoma and Lewis lung carcinoma; pulmonary metastases of this tumor are particularly sensitive to the effects of GANU. The effects of GANU on TLX5 lymphoma and Lewis lung carcinoma are less pronounced than those of BCNU and CCNU, as already reported for L1210 leukemia. In contrast with other results obtained with this tumor, chlorozotocin has a less pronounced effect than GANU, and virtually none in lung metastases of Lewis lung carcinoma.

Animals↗
PubMed1982

Mechanism of the antileukemic effects of 1-p-carboxamidophenyl-3,3-dimethyltriazene and its in vitro metabolites.

DM-CONH2, a dimethyltriazene active in prolonging the survival time of mice bearing TLX5 lymphoma, requires metabolic activation by liver homogenate supernatant and cofactors in order to exert in vitro cytotoxic effects on the same tumor cells, as determined by in vivo bioassay of their viability. From the examination of the metabolites produced during these in vitro experiments, it is found that in vitro cytotoxicity is attributable to the generation of MM-CONH2 by oxidative N-demethylation of DM-CONH2. Also the generation of DM-COO is observed, although this compound is not cytotoxic in vitro. The in vivo effects of DM-CONH2 and CM-COOK on TLX5 lymphoma are not caused exclusively by cytotoxic effects of the drugs, since they are evident also when no reduction in the number or viability of peritoneal tumor cells is evident, whereas these parameters are significantly reduced by MM-CONH2. The increase in survival time of mice bearing TLX5 lymphoma caused by the dimethyltriazenes used appears to be caused by the drugs without being subjected to metabolic activation, with a mechanism different from cytotoxicity for tumor cells.

Animals↗
PubMed1982

Methodologic problems encountered in the assay of proteinases in Lewis lung carcinoma, a mouse metastasizing tumor.

The proteolytic activity in homogenates and extracts of subcellular fractions prepared from subcutaneous Lewis lung carcinoma was determined using proteins and synthetic peptides as substrates. The presence of cathepsin D, plasminogen activator, cathepsin B-, cathepsin G- and elastase-like enzymes was observed. No difference was revealed between the proteolytic activity in homogenates of Lewis lung carcinoma, at the growth stage examined, and in homogenates of normal lung. High specific activities were found in the lysosomal extract, whereas decreasing activities were found in the nuclear extract, the homogenate and the postlysosomal mitochondrial supernatant; no active or trypsin-activatable collagenase activity was detected. The presence in the tumor tissue of these enzymatic activities is in agreement with their proposed role in the process of metastasis. The lack of differences between homogenates of tumor and normal lung tissue suggests that the use of whole cells is required to selectively study tumor proteinases specifically involved in tumor malignancy.

Animals↗
PubMed1982

Biochemical and biological characteristics of leucocyte proteinase inhibitors.

Pig leucocytes contain inhibitors of neutral and thiol proteinases. These proteins could be isolated from post-granule supernatant fraction as well as from nuclear extract using ion exchange chromatography, gel chromatography and affinity chromatography. Inhibitors differ in molecular weight, isoelectric point, immunologically and their inhibition ability against tested enzymes.

Animals↗
PubMed1982

Antitumor activity of N-diazoacetyl derivatives of glycine and phenylalanine against P388 leukemia and B16 melanoma in mice.

N-Diazoacetyl derivatives of glycine and phenylalanine show antitumor activity in mice bearing P388 leukemia or B16 melanoma. The presented data indicate that antitumor activity is shown by diazomethylamide derivatives of glycine and phenylalanine, in addition to that already established for the amino acid derivatives having an O-diazoacetyl group (azaserine) or a diazoketone structure (DON and azotomycin) and for 1,2-bis-diazoacetyl ethane.

Animals↗
PubMed1982

Some further characteristics of endogenous proteinase inhibitors.

Leucocytes and spleen contain four different types of protein proteinase inhibitors. Two of them can be inactivated by cathepsin D. In this work biochemical and immunological studies of the inactivation of I-2 by cathepsin D are presented. Polyacrylamide gel electrophoretic examinations indicate that cathepsin D inactivates I-2 by hydrolysis of the inhibitor molecule. The conversion of the active inhibitor into inactive protein proceeds catalytically. The studies on the inhibitor mechanism of the isoinhibitors of I-1 type explain the unusual inhibitor property of this type of inhibitor to inhibit two different types of proteinases, cysteine and serine. The evidence suggests that the inhibitory mechanism is based on an active sulfhydryl group of the inhibitor which may interact with the disulfide bridge of the inhibited proteinase.

Animals↗
PubMed1982

Prophylactic antimetastatic treatment with aryldimethyltriazenes as adjuvants to surgical tumor removal in mice bearing Lewis lung carcinoma.

The effects of two benzenoid dimethyltriazenes (1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt [DM-COOK] and 1-p-tolyl-3,3-dimethyltriazene), which have been previously shown to reduce the formation of spontaneous lung metastases in mice bearing subcutaneous Lewis lung carcinoma, have been investigated in mice implanted im with the same tumor in the calf of the hind leg. Primary tumor was removed surgically by amputation in mice treated with the tested compounds preoperatively, and the survival time of the animals was then determined. A high rate of cures, ranging from 23% to 43%, has been observed when the treatment consisted of eight or three daily doses prior to tumor removal; a single immediately preoperative dose was less effective and caused a 10% cure rate. Survival time of uncured mice was also significantly increased, particularly by DM-COOK. The division of the dose into two daily injections did not modify the activity of the triazenes, thus indicating that the antimetastatic coverage between two subsequent doses is not limited by fast pharmacokinetics or decomposition of the drugs. These results show that, at least in one animal system, aryldimethyltriazenes can be used also on palpable tumors as prophylactic adjuvants to surgery in order to reduce preoperative and intraoperative tumor spread.

Animals↗
PubMed1982

Metabolism and mechanism of the antileukemic action of isomeric aryldimethyltriazenes.

Mice bearing TLX5 lymphoma or P388 leukemia were treated with ortho, meta, and para isomers of the salts of (3,3-dimethyl-1-triazeno)benzoic acid. Survival time was markedly increased in mice given the para isomer; effects were less pronounced for the meta isomer and absent for the ortho isomer. The in vivo effects of the tested compounds did not correlate either with the propensity of the drugs to undergo oxidative N-demethylation and hydrolysis to diazonium cations or with in vitro cytotoxicity for TLX5 lymphoma cells. The para isomer did not reduce the number and viability of peritoneal TLX5 lymphoma cells after in vivo and in vitro treatment, whereas a dose-dependent reduction that can even result in the absence of clonogenic tumor cells occurred in the brains of the treated animals. These data indicate that the increased survival time of the tumor-bearing mice treated with the para isomer should not be ascribed to cytotoxic effects of the drug and might be attributed to inhibition of tumor cell dissemination in various organs of the host, as already observed for solid metastasizing tumors in mice.

Animals↗
PubMed1981

Selectivity of the antimetastatic and cytotoxic effects of 1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (+/-)-1,2-di(3,5-dioxopiperazin-1-yl)propane, and cyclophosphamide in mice bearing Lewis lung carcinoma.

The effects of two selective antimetastatic agents, 1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK), and (+/-)-1,2-di(3,5-dioxopiperazin-1-yl)propane, have been examined in comparison with those of a cytotoxic agent, cyclophosphamide, in mice bearing Lewis carcinoma. Cyclophosphamide at the two highest dosages causes a strictly related and pronounced inhibition (to less than 10%) of the weight of the s.c. tumor, spontaneous metastases, and lung colonies formed after i.v. injection of tumor cells (artificial metastases); this behavior is consistent with a purely cytotoxic mechanism. At the three dosages used, (+/-)-1,2-di(3,5-dioxopiperazin-1-yl)propane reduces the weight of spontaneous metastases to less than 3%. A dose-dependent reduction of artificial metastasis weight is also observed. At the highest dose, artificial metastasis weight is reduced to about 5%, and s.c. tumor mass is significantly lowered to 40%. These effects are consistent with the combined occurrence of cytotoxic and selective antimetastatic action, although the latter appears to be predominant. At the three dosages used, DM-COOK markedly depresses the weight and number of spontaneous metastases to about 10%, leaving the formation of artificial metastases unaffected and causing no significant effect on primary tumor growth. The effects of these agents on the fractional incorporation of [3H]thymidine in tumor cells further indicate that only DM-COOK is devoid of cytotoxic effects for pulmonary and s.c. tumors. In hosts pretreated with DM-COOK, no reduction in the formation either of spontaneous or of artificial metastases is observed. These data indicate that DM-COOK acts directly on tumor cells and that it presumably inhibits their release from the primary tumor into the bloodstream.

Animals↗