Quantitative studies on in vitro transformation of hamster chondrocytes

Hamster chondrocytes could be transformed in a quantitative assay system which used X-irradiated feeder layer cells. Morphological transformation occurred on addition of, 4NQO, but not in control cultures. Differentiation was classified into 3 types (good, poor and none); normal and transformed colonies contained similar proportions of the 3 types.

In vitro morphological transformation of cryopreserved hamster embryo cells with tobacco tar

Cryopreserved primary cultures of Syrian golden hamster embryo cells were used as the source of target and feeder cells for in vitro bioassay of carcinogenesis. Since cultures that gave the best overall response in a preliminary test were used for the bioassay, in almost every case a range of responses was obtained. By the use of this of this bioassay system, the capacities of tobacco tar and its subfractions to induce morphological transformation were examined. Some fractions induced typical morphologically transformed colonies. A close correlation was observed between morphological transformation and bacterial mutagenesis.

Differential Giemsa staining of sister chromatids after extraction with acids

Chromosomes of Chinese hamster strain cells were air-dried on slides after BrdU substitution for two or three rounds of replication. The preparations were treated with 20% PCA at 55 degrees C for 20-30 min, or 5N HCl at 55 degrees C for 15-20 min. After staining with Giemsa, unifilarly BrdU-substituted chromatids stained faintly and bifilarly substituted chromatids stained darkly. Such a pattern of sister chromatid differential staining was confirmed by the examination of metaphase cells grown with BrdU for three rounds of replication.

Modification of benzo(a)pyrene metabolism with microsomes by addition of uridine 5'-diphosphoglucuronic acid

The metabolism of benzo(a)pyrene (BaP) by rat liver microsomes was examined in the presence and absence of uridine 5'-diphosphoglucuronic acid (UDPGA). BaP metabolites were separated by high-pressure liquid chromatography. The normal chromatographic patterns of the metabolities were altered by the addition of UDPGA. At concentrations of UDPGA at which the elutions of dihydrodiol components were unchanged, phenol and quinone elution profiles were selectively decreased. The decreased activities of microsomal mixed-function oxidases by UDPGA were also observed with the use of the aryl hydrocarbon hydroxylase assay. The decrease may not be due to inhibition of those enzymes, but rather to formation of glucuronide conjugates with oxygenated BaP metabolites. These results suggest that glucuronidation may be important in the detoxification of BaP.

Adenoid squamous cell carcinoma of the oral mucosa: report of two autopsy cases

Two autopsy cases of adenoid squamous cell carcinoma of the oral mucosa proper are presented. Consecutive histologic examinations confirmed that adenoid transformation had occurred directly from within the pre-existing usual squamous cell carcinoma during the course of the disease. The adenoid pattern was reproduced in the lymph node metastases in both cases. The behavior and autopsy findings were not significantly different from those of usual squamous cell carcinoma of the oral mucosa.

Carcinogenic activity of 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide, a food additive, in mice and rats

The carcinogenicity of a food additive, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2), was studied in Wistar rats and CDF1 mice. The rats developed mammary tumors; the first appearing 9 months after the start of the experiment. In mice fed AF-2 diet, squamous cell carcinoma of the forestomach was observed in the 11th month. Some mice had metastases in the liver, spleen, lymph nodes and peritoneal cavity.

Eosinophilic leucocytes in nasal allergy--movement of enzymes

The changes in peroxidase of the granules of eosinophils were examined in cells in the nasal mucous membranes of persons allergic to house dust. There was a slight leakage of peroxidase from eosinophil granules immediately after placing an antigen-treated disc (house dust, Torii, 2560 microgram/disc) on the nasal mucous membrane. Leakage of peroxidase from the eosinophil granules into the cytoplasm, and extracellular release from some eosinophils, was greater 20 min after provocation, than at 30 sec. There were two forms of peroxidase release from the plasma membrane. In one, the granule membrane fused with the plasma membrane and the peroxidase was released from the cell through destruction of the two fused membranes. This was considered to be active secretion. In the other form, the plasma membrane was damaged by peroxidase released from the granules into the cytoplasm. This was considered to be passive release following degeneration of the cell.

Spontaneous ovarian tumors in domestic carp (Cyprinus carpio): light and electron microscopy

Massive abdominal enlargement was discovered in 8 adult carp (Cyprinus carpio) 4-6 years old, living in breeding ponds of carp fisheries in northern Japan. The abdominal enlargements rapidly progressed and the affected fish died within a few months. At necropsy, single or multiple tumors up to 20 cm in diameter were found in the abdominal cavities. Ovarian tissue identified within the tumor capsule in 4 fish supported the impression, based on gross anatomic features, that the neoplasm arose in the ovaries. Histologically, the tumors were composed mainly of various types of mesenchymal cells. In one sample, striated muscle was identified by electron microscopy; in another, squamous cell nests were intermixed with mesenchymal elements. Although some tumors had areas of cellular pleomorphism suggesting a malignant character, no evidence of invasion or metastasis was found. These neoplasms were classified tentatively as dysontogenetic tumors of the ovary, possibly teratoid in nature.

In vitro transformation of hamster chondrocytes by 4-nitroquinoline 1-oxide

Hamster sternal chondrocytes were transfored morphologically in vitro 29-51 days after exposure to 4-nitroquinoline 1-oxide for 3 h. The transformed chondrocytes were randomly oriented, piled up and grew continuously. These cells produced nodules when transferred to the cheek pouch of a hamster. Histologically, these nodules revealed chondromatous patterns. Untreated cells in the control cultures failed to produce nodules.

Effect of repeated bloodletting on the incidence of 2,7-FAA-induced rat leukemia

The oral administration of N,N'-2,7-fuorenylenebisacetamide (2,7-FAA) induced leukemia, especially mature granulocytic leukemia, in rats. 2,7-FAA was administered to the rats of the Wistar strain and a small amount of bloodletting was repeated for a long period. The incidence of leukemia and mature granulocytic leukemia became elevated by bloodletting. The induction of mature granulocytic leukemia might be increased by the promotion of granulopoiesis which had been suppressed by 2,7-FAA.

Configurational changes in chromatids from helical to banded structures

Induction of configurational changes in the helical chromatids of air dried chromosomes was used to explore the mechanism of G-banding. From the water-Giemsa stained metaphase spreads of Chinese hamster cells, chromosomes having clearly helical chromatids were selected and photographed. Then the chromosomes were decolorized, treated with trypsin, and restained with saline-Giemsa (1X SSC). Such procedures were repeatedly carried out upon the same chromosomes. Subsequent examination of the chromosomes showed that configurational changes from a helical structure to a banded structure had occurred. Some chromosomes revealed a variety of transitional changes between these two configurations. During the repeated G-banding treatments, the distances between bands along the same chromatids changed each time. The results obtained seem to indicate that the G-banding results from locally induced compaction of chromosomal materials along the chromatids.

In vitro transformation of newborn hamster cells induced by sodium nitrite

The in vitro carcinogenicity of sodium nitrite was examined. Addition of a high concentration of sodium nitrite (50 mM or 100 mM) to mass cultures of newborn hamster cells for 24 hr resulted in morphological transformation of the cells. The shortest time required for morphological transformation after this treatment was 21 days. Two of 5 transformed cultures produced progressively growing tumors when injected into young adult hamsters. These tumors were diagnosed as fibrosarcomas. In two control cultures of the same experimental groups, transformed cells appeared 10 weeks or more later than those in treated cultures. The chromosomes were analysed at several stages of transformation. In the early stages of transformation, chromosome number varied widely from near diploid to tetraploid, but later they became near diploid. Morphological alteration caused by sodium nitrite was also seen in a short-term assay, in which hamster embryonic cells (1 x 10(4) cells/60 mm dish) were treated and morphology was observed 8 days after the treatment.

Influence of blood collection on incidence of 2,7-FAA induced rat leukemia

The oral administration of N, N'-2,7-fluorenylenebisacetamide induced leukemia, especially mature granulocytic leukemia, in rats. The peripheral blood was examined on various schedules, once or twice a week for a long term. The blood volume lost by a blood collection was little, but it was not negligible in small animals such as rats when the loss was repeated. We investigated the relationship between the volume of blood loss and the incidence of leukemia. The incidence of leukemia rose as the volume of blood loss increased. There was a positive correlation between them. The induction of mature granulocytic leukemia was thought to be increased by the promotion of the granulopoiesis which had been suppressed by 2,7-FAA. It was concluded that the blood loss by repeated blood collection for examination raised the incidence of 2,7-FAA induced leukemia.

Histologic and electron microscopy observations on diethylnitrosamine-induced hepatomas in small aquarium fish (Oryzias latipes)

Liver neoplasms were induced in medakas (Oryzias latipes) by the addition of diethylnitrosamine (DENA) to their aquarium water at levels of 15-135 ppm for 8 weeks. After 13 weeks, 21 to 32 fish had developed hepatomas. Medakas are useful for further studies because they are highly susceptible to the carcinogenic effect of DENA, and the time for tumor induction is relatively short. Histologic type differed in the lesions of different fish and also within individual tumors. Some were typical trabecular hepatomas, others were anaplastic hepatomas or cholangiomas, or mixtures of these. Electron microscopy revealed an extensive rough-surfaced endoplasmic reticulum in a lamellar pattern, many mitochondria, and several round lysosomes in tumor cells. A few fat droplets with occasional crystalline ghosts were sometimes in the cytoplasm. The Golgi apparatus was not conspicuous. Some cells had highly developed microvilli that showed differentiation toward structures resembling bile capillaries.

Cytologic changes induced in rat livers cells by short-term exposure to chemical substances

All the hepatocarcinogens administered to rats markedly increased the mitotic rate in the liver. Except for alpha-benzene hexachloride and nitrosobutylurea, the nonhepatocarcinogens did not appreciably increase the mitotic rate. Cytogenetic analyses on the ploidy rate and chromosome abnormalities evidence qualitative differnces among mitotic liver cells in animals treated with hepatocarcinogens and chromosome changes in liver cells observed after the administration of hepatocarcinogenic substances may have some relation to an essential process in hepatocarcinogenesis.

Abnormal regeneration of hydra induced with vinblastine sulfate

The effect of vinblastine sulfate on the regeneration of hydra was examined. When the three segments of hydra (fore, mid, and hind segments) were treated with 0.01% vinblastine sulfate immediately after separation, transferred to normal culture medium, and observed for 7 days, various types of abnormal regeneration were observed, especially in the regenerates from the mid segments. Other segments of hydra did not reveal any abnormal pattern of regeneration, although incomplete regeneration or no regeneration of the segments was seen in the advanced period of the treatment. In the case of treatment of the three segments with 0.01% vincristine sulfate, no abnormal regeneration was seen, in spite of marked inhibition of regeneration which was observed in the advanced period of the treatment.

Effect of cigarette tar upon tissue culture cells. Neoplastic transformation of hamster lung cells by tobacco tar in tissue culture

Hamster lung fibroblastic cells were transformed into malignant cells in vitro by exposure to crude cigarette tar for 3 hours. Primary injuries of cells were observed between 2 and 48 hours after the treatment. Tar-treated cells showed nuclear pyknosis, cell necrosis, and enlarged, vacuolated cytoplasm. In one case giant cells were found at about 48 hours after treatment. Transformation occurred over 100 days after the treatment. The characteristics of transformed cells were random orientation of cells, with piling-up and criss-crossing, and continuous growth in vitro for over 300 days. Plating efficiency with treated cells was different from untreated cells. The transformed cells, cultured for 100 to 160 days, produced tumours when transplanted in cheek pouch of hamsters. The five of nine animals inoculated with 100 μg./ml. of tar treated cells (HT-100 strains) over 160 days in vitro died from tumours and others were killed for histological examinations and one of five animals transplanted with the cells of HT-10 strains within 121 days after the tar treatment. Histologically, the tumours were pleomorphic fibrosarcomas. Low doses (1 × 10(5) or less) of control cells failed to produce tumours after 270 days in culture. Contrarily, higher doses of 10(7) of control cells produced tumours when injected into the animals after 270 days in culture.