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Biomedical subjects

C Maltoni

Publications and source records attributed to C Maltoni.

At least 37 records · Page 2Linked to original sources
PubMed1989

Formaldehyde: an experimental multipotential carcinogen.

Male and female Sprague-Dawley rats of different ages at the start of the experiments (12 day embryos, and 7 and 25 weeks old) were administered fromaldehyde in drinking water at different doses (2,500 or 1,500, 1,000, 500, 100, 50, 10, 0 ppm). An increased incidence of leukemias and of gastro-intestinal tumors was observed in formaldehyde treated rats. Gastro-intestinal tumors are exceptionally rare in the rats of the colony used. These results, together with the ones obtained by other Authors on rats exposed by inhalation to formaldehyde, indicate that this compound is an experimental multipotential carcinogen. The experimental results presented in this report give scientific support to the epidemiological observation of a higher incidence of leukemias and of gastro-intestinal cancers among the people occupationally exposed.

Animals↗
PubMed1989

Benzene, an experimental multipotential carcinogen: results of the long-term bioassays performed at the Bologna Institute of Oncology.

In 1976, a systematic and integrated project of long-term carcinogenicity bioassays began at the Bentivoglio Experimental Unit of the Bologna Institute of Oncology. The Bologna experiments proved for the first time that benzene is an experimental carcinogen. These experiments demonstrated that benzene is carcinogenic when administered by ingestion and by inhalation and that it cause tumors in the various tested animal models (Sprague-Dawley rats, Wistar rats, Swiss mice, and RF/J mice). They also showed that benzene is a multipotential carcinogen, as it produces a variety of neoplasias in one or more of the tested animal models, including Zymbal gland carcinomas, carcinomas of the oral cavity, nasal cavities, skin, forestomach, and mammary glands, as well as angiosarcomas of the liver, hemolymphoreticular neoplasias, tumors of the lung, and possibly hepatomas. The Bologna experiments also indicated a clear-cut dose-response relationship in benzene carcinogenesis. This report presents the up-to-date results of the Bologna project. The need for more experimental research aimed at assessing the carcinogenic effects of low doses of benzene, of chemical mixtures containing benzene, and of benzene substitutes is emphasized. Also recommended are more comprehensive epidemiological investigations, extended to all types of malignancies, with particular regard to lung carcinomas.

Administration, Inhalation↗
PubMed1989

Recent results of carcinogenicity bioassays of fibres and other particulate materials.

Different types of natural, commercial and modified asbestos fibres were tested in a highly standardized manner by peritoneal injection into rats and mice in order to assess their carcinogenicity. Differences in mesotheliomatogenic effect were found between the various materials tested. Of particular interest is the finding that treatment of the fibres with phosphorus oxychloride and heating to 300 degrees C markedly reduces the carcinogenicity of chrysotile fibres.

Animals↗
PubMed1988

Carcinogenicity of vinyl chloride in Sprague-Dawley rats after prenatal and postnatal exposure.

Vinyl chloride was administered by inhalation, 7 hours daily, 5 days weekly, at concentrations of 2500 and 0 ppm, to Sprague-Dawley rats. The treatment was started on 13-week-old breeders and male and female offspring (12-day embryos). The breeders and part of the offspring were exposed for 104 weeks; the other part of the offspring was exposed for 15 weeks only. Under the experimental conditions, vinyl chloride caused an exceptionally high incidence of brain neuroblastomas, liver angiosarcomas, and hepatocarcinomas. The age at start and/or length of treatment may affect the onset of these tumors in different ways.

Administration, Inhalation↗
PubMed1988

Long-term carcinogenicity bioassay on vinylidene chloride administered by inhalation to Sprague-Dawley rats. New results.

Vinylidene chloride was administered by inhalation, 7 hours daily, 5 days weekly, at the concentration of 100 and 0 ppm, to Sprague-Dawley rats. The treatment was started on 13-week-old breeders, and male and female offspring (12-day embryos). The breeders and some of the offspring were exposed for 104 weeks; the other offspring were exposed for 15 weeks only. An increased incidence was found of malignant tumors and of leukemias, particularly in offspring treated for 104 weeks.

Administration, Inhalation↗
PubMed1988

Long-term carcinogenicity bioassays on acrylonitrile administered by inhalation and by ingestion to Sprague-Dawley rats.

Sprague-Dawley rats were exposed to acrylonitrile by inhalation at 40, 20, 10, 5 and 0 ppm, 4 hours daily, 5 days weekly, for 52 weeks and at 60 ppm, 4-7 hours daily, 5 days weekly. The latter treatment was started on 13-week-old breeders, and male and female offspring (12-day-embryos). The breeders and part of the offspring were exposed for 104 weeks; the other part of the offspring was exposed for 15 weeks only. Sprague-Dawley rats were also exposed to acrylonitrile by ingestion (stomach tube), in olive oil, at 5 mg/kg b.w., once daily 3 times weekly for 52 weeks. Under the tested experimental conditions, acrylonitrile was shown to be carcinogenic in Sprague-Dawley rats when given by inhalation and did not produce any carcinogenic effect when given by ingestion. In the inhalation experiment, acrylonitrile caused an increase in different types of tumors and the most noticeable acrylonitrile-related tumor was encephalic glioma.

Acrylonitrile↗
PubMed1988

Long-term carcinogenicity bioassays on styrene administered by inhalation, ingestion and injection and styrene oxide administered by ingestion in Sprague-Dawley rats, and para-methylstyrene administered by ingestion in Sprague-Dawley rats and Swiss mice.

Styrene was administered to Sprague-Dawley rats by inhalation (300, 100, 50, 25, 10 and 0 ppm, 4 hours daily, 5 days weekly, for 52 weeks); by gavage (250, 50 and 0 mg/kg b.w. in olive oil, once daily, 4-5 days weekly, for 52 weeks), by intraperitoneal injection (50 and 0 mg in olive oil, four times at 2-month intervals), by subcutaneous injection (50 and 0 mg in olive oil, once). Styrene oxide was administered to Sprague-Dawley rats by gavage as styrene (250, 50 and 0 mg/kg b.w. in olive oil, once daily, 4-5 days weekly, for 52 weeks). The animals were kept under observation until spontaneous death. Para-methylstyrene was also administered by gavage to Sprague-Dawley rats at 500, 250, 50, 10 and 0 mg/kg b.w., and to Swiss mice at 250, 50, 10 and 0 mg/kg b.w., in olive oil, once daily, 5 days weekly, for 108 weeks and 78 weeks, respectively. The study was terminated when the survival rate reached 50% in at least one experimental group. Styrene, when given by inhalation, was found to cause an increase in total (benign and malignant) and malignant mammary tumors. Styrene oxide produced a high incidence of tumors in the forestomach (papillomas, acanthomas, and in situ and invasive squamous cell carcinomas). Para-methylstyrene was not shown to be carcinogenic.

Administration, Inhalation↗
PubMed1988

Long-term carcinogenicity bioassays on propylene administered by inhalation to Sprague-Dawley rats and Swiss mice.

Propylene was administered by inhalation, 7 hours daily, 5 days weekly, at a concentration of 5000, 1000, 200 and 0 ppm, to Sprague-Dawley rats and Swiss mice. Groups of 120 male and 120 female rats (high-dose and controls) or 100 male and 100 female rats (mid- and low-dose) were treated for 104 weeks, and groups of 100 male and 100 female mice (each dose and controls) for 78 weeks. The animals were kept under observation until spontaneous death. Under the tested experimental conditions, the monomer was not shown to be carcinogenic.

Administration, Inhalation↗
PubMed1988

Long-term carcinogenicity bioassays on three chlorofluorocarbons (trichlorofluoromethane, FC11; dichlorodifluoromethane, FC12; chlorodifluoromethane, FC22) administered by inhalation to Sprague-Dawley rats and Swiss mice.

Three propellant chlorofluorocarbons, namely trichlorofluoromethane (FC11), dichlorodifluoromethane (FC12), and chlorodifluoromethane (FC22) were administered by inhalation at a concentration of 5000, 1000 and 0 ppm, 4 hours daily, 5 days weekly, for 104 and 78 weeks, to rats and mice, respectively. The animals were kept under observation until spontaneous death. Under the experimental conditions, all three compounds failed to show any carcinogenic effects.

Administration, Inhalation↗
PubMed1988

Long-term carcinogenicity bioassays on trichloroethylene administered by inhalation to Sprague-Dawley rats and Swiss and B6C3F1 mice.

Trichloroethylene was administered by inhalation, 7 hours daily, 5 days weekly, for 8 weeks, at concentrations of 600, 100 and 0 ppm, to Sprague-Dawley rats and Swiss mice; and for 104 weeks to Sprague-Dawley rats; and for 78 weeks to Swiss and B6C3F1 mice at concentrations of 600, 300, 100 and 0 ppm. The animals were kept under observation until spontaneous death. In the experiments reported herein, 3768 animals were studied. Under the experimental conditions, trichloroethylene appears to be carcinogenic in rats and mice (particularly in male Swiss mice). The most relevant finding was the dose-related increased incidence of Leydig cell tumors in male rats, and the onset of few renal tubuli adenocarcinomas at the highest dose, always in rats (4/130 males and 1/130 females). The renal tubuli adenocarcinomas were preceded by, and associated with, a characteristic lesion of the kidney: tubuli cell karyomegaly (megalonucleocytosis).

Adenocarcinoma↗
PubMed1988

Long-term carcinogenicity bioassays on methylene chloride administered by ingestion to Sprague-Dawley rats and Swiss mice and by inhalation to Sprague-Dawley rats.

Methylene chloride was administered to Sprague-Dawley rats and Swiss mice by ingestion (stomach tube), in olive oil, at the doses of 500, 100 and 0 mg/kg body weight, once daily, 4-5 days weekly, for 64 weeks, and to Sprague-Dawley rats by inhalation, at the concentration of 100 and 0 ppm, 7 hours daily, for 5 days weekly. The inhalatory treatment was started on 13-week-old breeders, and male and female offspring (12-day embryos). The breeders and part of the offspring were exposed for 104 weeks; the other part of the offspring was exposed for 15 weeks only. The most important findings were: (1) the increased incidence of pulmonary tumors in male mice treated by ingestion at 500 mg/kg body weight; (2) a not-significant increase in total malignant tumors in rats exposed by inhalation at 100 ppm for 104 weeks; and (3) a not-significant increase in total malignant mammary tumors in female rats given methylene chloride by ingestion at 500 mg/kg body weight.

Administration, Inhalation↗
PubMed1988

Further evidence of benzene carcinogenicity. Results on Wistar rats and Swiss mice treated by ingestion.

Wistar rats and Swiss mice were treated by ingestion (stomach tube) with benzene in olive oil at a dose of 500 and 0 mg/kg b.w. once daily, 4-5 days weekly, for 104 weeks (rats) or for 78 weeks (mice). In Wistar rats, benzene caused Zymbal gland carcinomas, carcinomas of the oral cavity, and carcinomas of the nasal cavities, and an increase in the incidence of total malignant tumors. In Swiss mice, benzene produced Zymbal gland carcinomas and dysplasias and an increase in the incidence of mammary carcinomas (in females), lung tumors, and total malignant tumors. These experiments further confirm that benzene is a multipotential carcinogen as was shown before by long-term bioassays performed on Sprague-Dawley rats in the same Experimental Unit.

Administration, Oral↗
PubMed1988

Incidence of pancreatic tumors and tumor precursors in Sprague-Dawley rats after administration of olive oil.

We studied the pancreata of 280 (140 males and 140 females) olive-oil-treated and 240 (120 males and 120 females) untreated Sprague-Dawley rats of the breed used at the BT Experimental Unit of the Bologna Institute of Oncology. Extra-virgin olive oil was administered by stomach tube, once daily, for 4-5 days weekly, for 2 years. The animals were kept under observation for as long as 130 weeks. Only a borderline increase in acinar cell adenomas and adenocarcinomas was observed. We found no increase in endocrine oncologic lesions.

Adenocarcinoma↗
PubMed1988

Results of recent experimental research on the carcinogenicity of natural and modified asbestos.

Long-term experimental bioassays were carried out on natural asbestos of different types and origin (crocidolite, chrysotile, amosite, antophyllite), on asbestos cement, and on industrially modified chrysotiles. The materials were tested on Sprague-Dawley rats by intraperitoneal and intrapleural injection. The experiments were carried out with highly standardized procedures on all materials to enable comparative evaluation of the results. The data presented confirm that asbestos of different types produces peritoneal and pleural mesotheliomas, show that asbestos cement is also mesotheliomatogenic, and demonstrate that the peritoneum is more responsive than the pleura. Furthermore, evidence is provided that the mesotheliomatogenic effects of different types of asbestos vary with the types and origin of the minerals, and that physical and chemical modifications of the natural chrysotile can lower its carcinogenic effect.

Administration, Inhalation↗
PubMed1988

First available results of long-term carcinogenicity bioassay on detergency zeolites (MS 4A and MS 5A).

Long-term experimental carcinogenicity bioassay was carried out on MS 4A and MS 5A zeolites. The materials were tested on Sprague-Dawley rats by intraperitoneal, intrapleural, and subcutaneous injection of 25 mg in 1 ml of H2O. The results of this bioassay (the onset of one peritoneal mesothelioma in a male rat treated by intraperitoneal injection of zeolite MS 4A) calls for further and more sophisticated tests on zeolites used as detergents.

Aluminum Silicates↗
PubMed1987

A cohort study on vinyl chloride manufacturers in Italy: study design and preliminary results.

A cohort mortality study of 5000 vinyl chloride manufacturers is ongoing in 9 Italian plants. They represent the entire workforce of those ever employed in the production of the monomer and its polymerization. The objectives of the study are to investigate the mortality of the exposed population and to clear up the carcinogenic spectrum of vinyl chloride. This article gives the results for 3 out of 9 plants, Rosignano, Ferrara and Ravenna, which represent about 25% of the total cohort. The expected deaths have been calculated using the mortality rates of the Italian population. For the deceased persons information from the death certificates were used in the analysis of mortality; additional clinical and pathological data were collected (best pathological evidence, b.p.e.). In Ferrara a statistically significant excess for all malignant tumors and lung cancer was detected. In Rosignano and Ravenna the number of observed deaths were small and therefore no comments can be made on cancer mortality. The cohort study is ongoing in the 6 remaining cohorts and the future analysis will consider duration and level of exposure and latency.

Adult↗