Mouse Forestomach Research Articles

Haemorheological Study during the Process of Tumor Development after Subcutaneous Transplantation of Mouse Forestomach Carcinoma (FC) Cells

A metastatic tumor model of mouse forestomach carcinoma (FC) was used in this study. Tumor cells were subcutaneously transplanted into right costal region of inbred 615-strain mice. Animals were killed on the 3rd, 6th, 9th, 12th and 15th day. Histological and haemorheological examinations were performed. Based on the histological findings the development of the tumor was divided into 5 stages; i.e. latent stage, invasive stage, early stage of metastasis, middle stage of metastasis and late stage of metastasis, corresponding with 3rd, 6th, 9th, 12th and 15th day after transplantation of mouse forestomach carcinoma. Results of haemorheological studies indicated that plasma and blood viscosity elevated in the invasion and early metastatic stages and the increased viscosity of blood was able to promote metastasis during the early stage of tumor development, while the tumor developed in the middle and late metastatic stages when the values of plasma viscosity, blood viscosity, aggregation of red blood cells and haematocrit decreased but the rigidity of red blood cells increased in these periods.

Biotin-labeled plasmid DNA probes for detection of epithelium-associated strains of lactobacilli.

Biotin-labeled DNA probes prepared from whole plasmids (5.5 and 4.8 kilobases) of two lactobacillus strains (Lactobacillus delbrueckii 21 and Lactobacillus reuteri 100-23) were used to detect the homologous bacteria in microtome-cryostat-prepared sections of murine forestomach. The forestomach sections were incubated on nylon filter membranes placed on agar plates and, after lysis of the lactobacillus cells and denaturation of their DNA, were used in hybridization experiments with the strain-specific DNA probes. Hybridization of the probes to membranes containing sections from lactobacillus-free mice did not occur. The probes detected the presence of homologous strains of lactobacilli in sections cut from the forestomach of mice harboring one or both of the strains.

Further studies on the biological characteristics of an endogenous colon mitosis inhibitor: Comparison with some structurally related peptides

Previous work indicates that the colonic epithelial cell proliferation in mice is reversibly inhibited by the tripeptide pGlu-His-GlyOH found in aqueous extracts of the intestine. In the present study we examined the possible tissue specificity of the colon mitosis inhibitor. The mitotic rate in the small intestine, epidermis and forestomach in mice was registered after a single i.p. injection of the tripeptide. A significantly reduced rate of cell renewal was found at 18 h in the epidermis whereas no inhibition was observed in the forestomach or ileal epithelium. To investigate whether the amino acid sequence of the tripeptide is essential for the inhibitory effect, three structurally related bioactive peptides were tested and compared to the effect of CMI. CMI showed a bell-shaped dose-response relationship as previously shown, whereas the mitotic rate was not reduced in the colonic epithelium after treatment with either an epidermal mitosis inhibitory pentapeptide, or the dipeptide pGlu-GlyOH, or an analogue of luteinizing hormone-releasing hormone. The efficacy of the tripeptide was dependent on the basal rate of cell renewal in the colonic epithelium. When the tripeptide was given at the circadian nadir of cell proliferation a delayed reduction of proliferative activity was observed at 6 h after treatment, whereas treatment when the rate of cell proliferation was at its circadian zenith gave an immediate mitotic inhibition.

The intermediate filament system of the keratinizing mouse forestomach epithelium: Coexpression of keratins of internal squamous epithelia and of epidermal keratins in differentiating cells

The internal epithelium of mouse forestomach represents a fully keratinized tissue that has many morphological aspects in common with the integumental epidermis. In the present study we have, therefore, analyzed keratin expression in the total epithelium, in subfractions of basal cells and in living and dead suprabasal cells that were obtained by Percoll density gradient centrifugation of trypsin-dissociated forestomach keratinocytes. The keratin analysis revealed that basal forestomach keratinocytes synthesize the same keratin types as basal epidermal cells (60000, 52,000 and 47,000 daltons), whereas differentiating cells contain both the epidermal suprabasal keratin pair (67,000 and 59,000 daltons) and the suprabasal keratin pair characteristic for other internal squamous epithelia (57,000 and 47,000 daltons). Indirect immunofluorescence using an antibody recognizing the members of the epidermal-type suprabasal keratin pair and in-situ-hybridization experiments using specific cDNA probes for the members of the internal-type keratin pair showed that the two keratin pairs are uniformly coexpressed in living suprabasal forestomach keratinocytes. Furthermore, it could be shown that distinct cells in the basal cell layer acquire the ability to express both the 67,000/59,000 dalton and the 57,000/47,000 dalton keratin pair and that some basal cells apparently lose the ability to synthesize mRNAs for basal keratins.

Tumor promoting activity of teleocidin in skin and forestomach of mice initiated transplacentally with 7,12-dimethylbenz(a)anthracene.

Experiments on the effect of transplacental initiation with 7,12-dimethylbenz(a)anthracene (DMBA) and postnatal promotion with teleocidin were carried out in mice. The percentage of tumor-bearing mice among females treated with DMBA transplacentally on day 17 of gestation and postnatally by topical application of teleocidin to the skin of the back was 73.3% in week 30, whereas that among females treated with DMBA on day 10 of gestation and postnatally by topical application of teleocidin was 20.0%. This indicates that teleocidin shows potent tumor promoting activity on mouse skin in a transplacental initiation and postnatal promotion protocol. Furthermore, in the males treated with DMBA transplacentally on day 17 of gestation and given diet containing 0.01% teleocidin postnatally five tumors of the forestomach were found in 5 of 19 effective mice (26.3%) in week 52. One of these five tumors was a squamous cell carcinoma, and the others were papillomas. This indicates that teleocidin also has tumor promoting activity in the forestomach of mice.

Rat and Mouse Forestomach Tumors Induced by Chronic Oral Administration of Styrene Oxide23

Styrene oxide (CAS: 96-09-3) was administered in corn oil by gavage three times a week at two dose levels to groups of 52 male and 52 female F344 rats and 52 male and 52 female B6C3F1 mice for 2 years, after which the surviving animals were killed and examined histopathologically. The doses given to rats were 550 and 275 mg/kg (body wt) per treatment; in mice the two doses were 750 and 375 mg/kg (body wt) per treatment. The main pathologic findings were high incidences of squamous cell carcinomas or papillomas of the forestomach in both sexes of both rats and mice. These neoplasms were virtually absent from the 52 controls of either sex of both species given parallel treatment with corn oil alone. There was a statistically significant increase in the incidence of hepatocellular neoplasms in male mice receiving 375 mg styrene oxide/kg. Styrene oxide is carcinogenic to both sexes of F344 rats and B6C3F1 mice when administered orally in corn oil.

Staining patterns of rodent squamous epithelia by monoclonal anti‐keratin antibodies

Anti-keratin staining patterns were examined by immunofluorescence in the epidermis, oral mucosa and forestomach of rats and mice by monoclonal antibodies AE1 and AE2. In contrast to human tissues enzymatic pretreatment of sections was necessary even when fresh-frozen tissue was used, suggesting masking of the antigens in vivo. AE1 stained the cytoplasm of spinous cells in most epithelia, whereas basal cell staining varied. AE2 showed suprabasal cytoplasmic staining in epidermis, forestomach and palate, whereas the other epithelia were stained only in keratohyalin granules and membranes of cornified cells. In some epithelia a small number of irregularly distributed basal cells stained positive with AE2, indicating heterogeneity in the basal cell compartment. Thus, the anti-keratin staining pattern varies both regionally and, as earlier shown in human epithelium, with the stage of maturation of cells within a given epithelium. The present study provides a basis for further studies of epithelial differentiation during normal and pathologic development.

Induction of hepatocellular carcinoma and highly metastatic squamous cell carcinomas in the forestomach of mice by feeding 2-amino-3,4-dimethylimidazo[4,5-f]quinoline.

2-Amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), a potent mutagen which was isolated from grilled sardines, was tested for carcinogenicity in CDF1 mice. Mice were given diet containing 0.04 or 0.01% MeIQ for 91 weeks. The incidences of liver tumors (hepatocellular carcinomas and hepatocellular adenomas) in female mice given 0.04 and 0.01% MeIQ were significantly higher than those in controls. The incidences of forestomach tumors (squamous cell carcinomas and papillomas) were also significantly higher in both sexes of mice given MeIQ. About 40% of the squamous cell carcinomas that developed in mice given diet containing 0.04% MeIQ metastasized to the liver.

Sequential changes of the forestomach of F344 rats, Syrian golden hamsters, and B6C3F1 mice treated with butylated hydroxyanisole.

Butylated hydroxyanisole (BHA) was given to F344 rats, Syrian golden hamsters and B6C3F1 mice at 2 doses for up to 104 weeks. The two doses were 2.0% and 1.0% for rats and hamsters, and 1.0% and 0.5% for mice. Animals were sacrificed sequentially at 8-week intervals from week 8 to week 104, and the carcinogenic effects of BHA on the forestomach were examined histopathologically. Papillomas and carcinomas were found in rats, hamsters and mice. In rats, papillomas first appeared in week 8 in the group given the higher level of BHA and in week 56 in that given the lower level. The first carcinoma was observed in week 48 in rats given the high level, while no carcinoma was observed in rats given the lower level. In hamsters, papillomas appeared in week 8 in both BHA-treated groups, and in both groups, the incidence of papillomas was much higher than in BHA-treated rats. Squamous cell carcinomas were observed in 4 hamsters (10.0%) among those that survived more than 64 weeks on treatment with the higher level of BHA and in 4 (7.3%) among those treated with the lower level. In mice, papillomas were induced by BHA in both BHA-treated groups after more than 88 weeks. Although the incidence was not statistically significant, carcinoma was also seen in mice, suggesting that BHA may also be carcinogenic to mouse forestomach.

Specificity of induction of cancer protective enzymes by analogues of tert-butyl-4-hydroxyanisole (BHA).

Protection by 2(3)-tert-butyl-4-hydroxyanisole (BHA) and related phenols against chemical carcinogens, mutagens and other toxins has been attributed to the elevation of tissue levels of non-oxygenative detoxification enzymes. To analyze the mechanisms and specificity of these enzyme inductions, we synthesized a series of mono- and dialkyl ethers of tert-butylhydroquinone (R1O-[(CH3)3C-C6H3]-OR2) and its dimer. The abilities of these compounds to elevate the cytosolic specific activities of glutathione S-transferases (measured with 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene) and of NAD(P)H: quinone reductase in liver, upper small intestine and forestomach of female CD-1 mice were evaluated. The animals were fed five daily doses of 50 mumoles of each monomer (or 25 mumoles of each dimer). The structures of the monomers examined were: R1 = H and R2 = CH3 (I), R2 = C2H5 (VI), R2 = (CH2)2CH3 (VIII), R2 = CH(CH3)2 (X); R1 = CH3 and R2 = C2H5 (VII), R2 = (CH2)2CH3 (IX), R2 = CH(CH3)2(XI); R2 = CH3 and R1 = C2H5(III), R1 = (CH2)2CH3(IV) and R1 = CH(CH3)2 (V). In addition, the monomethyl (XIII), monoethyl (XIV) and mono-n-propyl (XV) ethers of BHA dimer (XII; 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxybiphenyl) were also prepared. Under the conditions tested, all compounds were ineffective as enzyme inducers in the forestomach but produced coordinate induction of enzymes (generally 2- to 6-fold) in the cytosols of liver and mucosa of proximal small intestine. Increases in bulk of R1 and R2 beyond methyl groups tended to decrease the inductive potency of both monomers and dimers. The lack of strict structural specificity suggests that the induction depends on metabolic conversion of the analogues to common types of metabolites.

The distribution of blood group antigens in rodent epithelia.

The pattern of distribution of antigens cross-reacting with antibodies to human blood group antigens A and B and two precursor molecules was examined by immunofluorescence in the epidermis, oral mucosa and forestomach of rats and mice. Staining for blood group antigen A was negative. In all epithelia examined, blood group antigen B was present at the surface of basal and parabasal cells, and the H antigen at the surface of spinous cells. N-acetyllactosamine was present on the cell membranes in the upper spinous and granular cell layers of epidermis and forestomach epithelium and was not expressed in the oral epithelia except for a limited area in the dorsal tongue epithelium. Thus, the expression of antigen varies both regionally and, as earlier shown in human epithelium, with the stage of maturation of cells within a given epithelium. The observed sequence of expression of these antigens during maturation differs from that of human epithelia, but the present study provides a basis for further experimental studies of the role of cell surface antigens in epithelial homeostasis and maturation.

Evidence for binding of metabolically activated 1,2-dibromoethane to chromatin of forestomach and liver

The covalent binding of metabolically activated 1,2-dibromoethane (DBE), a potent carcinogen, to chromatin constituents of forestomach and liver was examined in vitro . Chromatin was prepared from forestomach and liver of B6C3F1 mice and characterized. In order to activate DBE, microsomes and cytosol were isolated from mouse forestomach and liver and incubated with [ 14C]-DBE in the presence of a NADPH regenerating system. Results demonstrate that DBE bound covalently to the same extent to protein of microsomes and chromatin isolated from forestomach and liver. On the contrary, DBE bound significantly more to chromatin DNA of forestomach or liver than it did to salmon sperm DNA. It appears from these results that the metabolically activated DBE is more reactive to homologous DNA than exogenous DNA. Fractionation of DBE-bound chromatin protein into histone and nonhistone proteins resulted in higher binding of DBE to non-histone than to histone proteins isolated from forestomach and liver.

Carcinogenic Effect of Carbazole in the Liver of (C57BL/6N × C3H/HeN)F<sub>1</sub> Mice<xref ref-type="fn" rid="FN2">2</xref><xref ref-type="fn" rid="FN3">3</xref>

The carcinogenic effect of carbazole (9H-carbazole) in (C57BL/6N X C3H/HeN)F1 (B6C3F1) mice was examined. Groups of 50 mice of both sexes were given a basal diet containing 0.6, 0.3, or 0.15% carbazole for 96 weeks and were then placed on an unsupplemented basal diet until they were killed at week 104. Mice surviving longer than 52 weeks were included in effective numbers. Significant increases in the induction of neoplastic lesions were found in the livers and forestomachs of mice given carbazole as compared to the control groups. The lesions in the livers were classified into two types, neoplastic nodules or hepatocellular carcinomas. The incidences of both types of lesions were almost 100% in mice treated with carbazole, and both types of lesions were significantly increased in all mice except the males given 0.6% carbazole in their diet. The incidences of hepatocellular carcinomas were in general higher than those of neoplastic nodules. Though not statistically significant, increased incidences of pulmonary metastases were found in the groups given carbazole. Significantly increased incidences of neoplastic lesions and papillomas in the forestomach in all groups of female and male mice were also noted in the mice fed 0.6% carbazole. Squamous cell carcinoma induction was significantly different in male mice given 0.6% carbazole as compared to controls. These results indicate that carbazole is carcinogenic to the liver and forestomach in B6C3F1 mice and suggest that carbazole may be an environmental carcinogen relevant to cancer risk in humans.

Influence of daily subcutaneous administration of 6-methylprednisolone and oral application of 30% saline solution on tumorigenesis induced in mouse stomach by single application of 7,12-dimethylbenz(a)anthracene

Combined treatment with DMBA, 6-methylprednisolone, and 30% saline solution induced papillomas in the forestomach of mice after a median latent period of 25 days.

Effect of butylated hydroxyanisole on the metabolism of benzo[a]-pyrene and the binding of metabolites to DNA, in vitro and in vivo, in the forestomach, lung, and liver of mice.

Effect of butylated hydroxyanisole on the metabolism of benzo[a]-pyrene and the binding of metabolites to DNA, in vitro and in vivo, in the forestomach, lung, and liver of mice.

Enhancement of Glutathione <italic>S</italic>-Transferase Activity of the Mouse Forestomach by Inhibitors of Benzo[<italic>a</italic>]pyrene-Induced Neoplasia of the Forestomach<xref ref-type="fn" rid="fn2">2</xref><xref ref-type="fn" rid="fn3">3</xref>

The effects of glutathione S-transferases (GST) activity and acid-soluble sulfhydryl levels of a number of compounds previously investigated for their capacity to inhibit benzo[a]pyrene (BP)-induced neoplasia of the mouse forestomach were determined. Five of the compounds studied increased the GST activity of the forestomach 78-182%. The five compounds were: p-methoxyphenol, 2-tert-butyl-4-hydroxyanisole, coumarin, alpha-angelicalactone, and benzyl isothiocyanate. With the exception of benzyl isothiocyanate. With the exception of benzyl isothiocyanate, these compounds also increased acid-soluble sulfhydryl levels, but to a lesser magnitude. All five chemicals inhibited BP-induced neoplasia of the forestomach. These data indicate that enhancement of the GST activity by an amount of about 75% or greater is associated with a reduced carcinogenic response of the forestomach to BP. The data also suggest that such enhancement might be used as a method of identifying compounds likely to inhibit BP and other carcinogens detoxified in a similar manner. Inasmuch as inhibition of the action of carcinogens may involve mechanisms other than detoxification by GST, the failure to increase GST activity substantially does not rule out the possibility of a compound being an inhibitor.

Dihydrosafrole and stomach tumours: Reuber, M. D. (1979). Neoplasms of the forestomach in mice ingesting dihydrosafrole. Digestion19, 42

Dihydrosafrole and stomach tumours: Reuber, M. D. (1979). Neoplasms of the forestomach in mice ingesting dihydrosafrole. Digestion19, 42

Neoplasms of the Forestomach in Mice Ingesting Dihydrosafrole

The maximal tolerated doses of dihydrosafrole, safrole, and isosafrole were given by continuous oral administration, starting at the age of 7 days, to both sexes of two hybrid strains of mice - (C57BL/6 X C3HAnf)F1 and (C57BL/6 X AKR)F1. Hyperplasia and carcinomas of the forestomach were significantly increased in female mice of both strains and in male mice of the latter strain ingesting dihydrosafrole. By contrast, neoplasms of the forestomach were not increased in mice receiving safrole or isosafrole. Mice with neoplasms of the stomach generally did not have neoplasms of the liver.

Inhibition of Carcinogenic Effects of Polycyclic Hydrocarbons by Benzyl Isothiocyanate and Related Compounds2

Benzyl isothiocyanate and phenethyl isothiocyanate, two compounds found in cruciferous plants, and phenyl isothiocyanate, a synthetic compound, all inhibit 7,12-dimethylbenz[a]anthracene (CMBA)-induced mammary tumor formation in female Sprague-Dawley rats when administered 4 hours prior to the DMBA. Comparable studies in which benzyl isothiocyanate was administered 24 hours before or 4 hours after DMBA showed almost complete loss of inhibition. Additions of benzyl isothiocyanate or phenethyl isothiocyanate to a diet containing CMBA inhibited formation of neoplasms of the forestomach and pulmonary adenomas in female ICR/Ha mice. Addition of benzyl isothiocyanate to a diet containing benzo[a]pyrene also inhibited carcinogenesis of the mouse forestomach due to this carcinogen. The finding of two additional anutrient dietary compounds which inhibit chemical carcinogenesis focuses on the possibility that dietary constituents of this nature may diminish the impact of exposures to chemical carcinogens.

Carcinomas of the liver and forestomach in mice ingesting chlorobenzilate.

The maximal tolerated dose of chlorobenzilate was given by continuous oral administration, starting at the age of 7 days, to both sexes of two hybrid strains of mice-(C57BL/6 X C3HAnf)F1 and (C57BL/6 X AKR)F1. There was an increased incidence of tumors in one or more organs in male mice of both strains and female mice of the (C57BL/6 X C3HAnf)F1 strain. Male mice of both strains developed significantly elevated incidences of carcinomas of the liver. Female (C57BL/6 X C3HAnf)F1 strain mice had a significantly increased incidence of hyperplasia and carcinomas of the forestomach.