Presence of a no-observed effect level for enhancing effects of development of the alpha-isomer of benzene hexachloride (alpha-BHC) on diethylnitrosamine-initiated hepatic foci in rats.

The dose dependence of the promoting effects of the alpha-isomer of benzene hexachloride (alpha-BHC) on hepatocarcinogenesis was investigated in a medium-term rat liver bioassay (Ito test). A total of 195 F344 male rats, 6 weeks old, were given a single intraperitoneal injection of diethylnitrosamine (DEN) at the start of the experiment and subjected to two-thirds partial hepatectomy at week 3. Two weeks after the administration of DEN, alpha-BHC were fed to rats at doses of 0, 0.01, 0.1, 0.5, 1, 2, 4, 7.5, 15, 30, 60, 125 and 500 ppm in diet for 6 weeks. All surviving animals were killed at week 8, and their livers were examined immunohistochemically for detection of glutathione S-transferase placental form (GST-P)-positive foci, surrogate preneoplastic lesions. Quantitative values for numbers and areas were dose-dependently increased in rats given alpha-BHC at 0.5-500 ppm. However, those for groups treated with 0.01 and 0.1 ppm were decreased, albeit not significantly in comparison to the controls. Cytochrome P450 3A2 (CYP3A2) protein levels and activities showed a good correlation to the number and area of GST-P-positive foci. These results support evidence of hormesis and indicate a no-observed effect level for alpha-BHC promoting potentials may exist regarding rat liver carcinogenesis, which correlates with expression of CYP3A2 in the liver.

[Effects of an oxacephem antibiotic on liver function in orthopedic surgery].

The subjects were 531 patients who underwent orthopedic surgery. Flomoxef was administered, and liver function was examined before and after administration. Abnormal liver function after administration of flomoxef was found in 14.3% of patients. In male patients, a high rate of 18.8% was observed. A particularly high rate of 37.0% was obtained among patients who showed GOT values of more than 40 U/L before treatment with flomoxef. The prevalence of abnormal GOT and GPT values after administration of flomoxef was 3.6% and 13.2%, respectively. These values were significantly higher than those obtained with other cephem antibiotics. These rates of occurrence of abnormally high GOT and GPT are obviously higher than those submitted at the time of approval and reported in the drug use investigation. The prevalence of abnormal liver function values was high in patients receiving flomoxef, and particularly high in male patients and patients whose GOT was high before administration of flomoxef. Therefore, sufficient check of liver function appears important when administration of flomoxef to these types of patients is intended.

Expression of the cyclin D1 gene in rat colorectal aberrant crypt foci and tumors induced by azoxymethane.

Cyclin D1 is a cell cycle regulator which is overexpressed in a variety of human cancers. We examined overexpression of cyclin D1 in several stages of rat colorectal carcinogenesis induced by azoxymethane (AOM) treatment. The level of cyclin D1 in 13 aberrant crypt foci (ACF) (atypical hyperplasias), 22 colorectal tumors (14 non-invasive adenocarcinomas and eight invasive adenocarcinomas) was assessed by immunostaining using a polyclonal antibody. Cell proliferation of these samples was investigated by measurement of 5-bromo-2'-deoxyuridine-labeling index. Indices of cyclin D1-positive cells in adenocarcinomas and atypical hyperplasias were significantly higher than that in normal crypts (P < 0.05). Moreover, cyclin D1-positive rates in the two types of adenocarcinomas were significantly higher than that in atypical hyperplasias (P < 0.05). Staining of nuclear cyclin D1 was very strong in almost all adenocarcinomas and four ACF. Comparisons of BrdU-positive indices in colorectal lesions showed similar results to the cyclin D1-positive indices. These results suggested that overexpession of cyclin D1 occurs early in the multistep carcinogenesis, and plays an important role in rat colorectal carcinogenesis.

An autopsy report of graft-versus-host disease (GVHD) following blood transfusion.

A case of graft-versus-host disease (GVHD) associated with blood transfusion in a 71-year-old man is reported. The patient received transfusions (irradiation red cells M.A.P 14 units, fresh frozen plasma 11 units) and developed features of GVHD including fever, a skin rash, diarrhea, liver dysfunction, hypoplastic bone marrow, and pancytopenia. He died on day 32 posttransfusion. Pathologically, lymphocyte infiltration of skin and liver lesions, degeneration of small bile ducts, crypt cell necrosis in the gastrointestinal tract, and bone marrow hypoplasia were observed. Immunohistochemically, infiltrating lymphocytes were CD8+ T type, the result suggesting that they role a part in posttransfusion GVHD.

Infrequent somatic mutation of the adenomatous polyposis coli gene in aberrant crypt foci of human colon tissue.

BACKGROUND: The authors examined somatic mutations of the adenomatous polyposis coli (APC) gene in 84 human aberrant crypt foci (ACF) to determine whether APC gene mutations were involved in the histologic progression of ACF. METHODS: Mutation cluster regions of the APC gene were subjected to polymerase chain reaction single-strand conformation polymorphism analysis and direct sequencing. RESULTS: Four kinds of deletion were detected in the mutation cluster regions of APC gene in five ACF. APC mutation was detected in 1 of 18 ACF with Stage I abnormalities (6%). Four of 10 adenomatous ACF (40%) harbored the mutation. There were no mutations in 56 hyperplastic ACF. CONCLUSIONS: These results suggest that APC mutations may be involved initially in only a limited number of adenomas in ACF.

Neoplastic transformation of rat colon epithelial cells by expression of activated human K-ras.

Somatic mutations of the K-ras oncogene play an important role in colorectal carcinogenesis. We determined whether rat colon epithelial cells could be transformed by introducing retroviruses carrying the activated human K-ras oncogene alone. Primary epithelial cells from the rat distal colon were infected with retroviruses carrying wild-type and two types of activated K-ras (asp and val at codon 12) cDNAs. Cells infected with the wild-type K-ras virus showed no change in morphology and died within 3 weeks, whereas the activated K-ras virus-infected cells underwent morphological changes within 3 days and continued to proliferate. From these cells, several cell lines were subsequently established. Epithelial cells transformed by activated K-ras formed colonies in soft agar culture and tumors in athymic nude mice. Multiple copies of human K-ras genes and large amounts of K-ras mRNAs and proteins were found in the transformed cells. These data suggest that overexpression of activated K-ras transforms rat colon epithelial cells.

Expression and localization of ornithine decarboxylase in reversible papillomatosis induced by uracil in rat bladder.

Direct mechanical irritation by uracil calculi formed following feeding of 3% uracil in the diet to male rats produces severe papillary hyperplasia (papillomatosis, which is reversible) of bladder epithelium. To evaluate the mechanism of the appearance of uracil-induced papillomatosis, we examined the changes of the enzyme activity and the localization of ornithine decarboxylase (ODC), as well as polyamine biosynthesis, and epithelial proliferation, that accompany the sequential bladder epithelial changes following administration and withdrawal of uracil. Moreover, expression of ODC mRNA was investigated using northern blotting and localization of ODC mRNA was demonstrated using in situ hybridization. ODC activity during uracil administration was maintained at a high level compared to that in normal epithelium, but sharply decreased after cessation of uracil treatment. The accumulation of ODC protein was observed in the proliferating bladder epithelium by immunohistochemical examination and western blotting analysis, and even after cessation of treatment, the protein binding to anti-ODC antibody remained mildly elevated. Sequential changes of proliferating cell nuclear antigen (PCNA)-positive cells in the epithelium during the development and disappearance of papillomatosis correlated with ODC activity. ODC mRNA was expressed strongly in the proliferating epithelium in rats treated with uracil and weakly in normal epithelium, in accordance with the location of ODC protein. Consequently, our data demonstrate that cell proliferation in the development of papillomatosis is closely associated with polyamine metabolism, and moreover suggest that ODC activity is up-regulated at a post-translational step.

Reversibility and apoptosis in rat urinary bladder papillomatosis induced by uracil.

Apoptosis is a morphologically and biochemically distinct form of cell death which determines specific patterns of tissue size and shape and balances cell proliferation. In the present study, the sequence of cellular proliferative alterations in urinary bladder epithelium associated with uracil-induced reversible urinary calculi was investigated in male F344 rats. Group 1 consisted of 45 rats, 6 weeks old at commencement of the experiment, which were given a diet containing 3% uracil for 8 weeks and were then returned to basal diet until week 20. Five rats were killed at each of weeks 2, 4, 8, 9, 10, 11, 12, 14 and 20. Group 2 consisted of 15 rats which were given basal diet for 20 weeks. Five rats were killed at each of weeks 0, 8 and 20. Microscopic, reversible papillomatosis, which showed papillary projections of epithelial proliferation, was seen in the urinary bladder of all rats in group 1 through week 8. No epithelial lesions were apparent in any of rats in group 2. Anti-Le(y)(BM-1/JIMRO)-positive areas of the urinary bladder epithelia were immunohistochemically seen in all rats of group 1 at weeks 2-12. At week 9 the percentage of anti-Le(y)-positive areas reached a maximum. Nick-end labeling stained nuclei of cells in the urinary bladder epithelium were observed in all rats of group 1 at weeks 4-14. At week 10 the labeling index was at a maximum. Proliferating cell nuclear antigen (PCNA)- and cyclin D1-positive cells of the urinary bladder epithelium were observed in group 1 at weeks 2, 4 and 8, however, at week 9 there were no PCNA- and cyclin D1-positive cells. In urinary bladder papillomatosis the simultaneous existence of apoptotic cells and proliferating cells was shown by double staining with anti-Le(y) (BM-1/JIMRO) and for PCNA. At week 10 apoptosis, stained by BM-1 and nick-end labeling, occurred extensively in regressing urinary bladder papillomatosis. Agarose gel electrophoresis of DNA in regressing papillomatosis at week 9 showed DNA fragmentation. Thus, these results indicate that apoptosis occurs in the process of papilloma regression following withdrawal of uracil treatment.

High frequency of K-ras mutations in human colorectal hyperplastic polyps.

BACKGROUND: Hyperplastic polyps are common benign colorectal polyps, and are thought to have little association with malignant tumours in the colorectum. However, several reports suggest that some hyperplastic polyps may develop into colorectal neoplasms. AIM: To clarify genetic alterations in colorectal hyperplastic polyps. METHODS: Twenty eight colorectal polyps having serrated components were resected from patients endoscopically. The K-ras gene mutations in codons 12 and 13 were analysed by PCR-RFLP. Intranuclear p53 protein was immunostained by the avidin-biotin complex method. RESULTS: A mutation of the K-ras gene was detected in nine (47%) of 19 hyperplastic polyps, and five (56%) of nine adenomas. p53 protein nuclear accumulation was detected immunohistochemically in two (22%) of nine adenomas, but not in any of the hyperplastic polyps. CONCLUSION: Some hyperplastic polyps may be true neoplastic lesions, and could be precursors of malignant neoplasia.

Induction of aberrant crypt foci and flat-type adenocarcinoma in the colons of dogs by N-ethyl-N'-nitro-nitrosoguanidine and their sequential changes.

Sequential endoscopic observation of dog colons was performed during colon carcinogenesis. Two beagle dogs were given suppositories containing N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) every day for five months. In month 3, aberrant crypt foci (ACF), a putative preneoplastic lesion, were found in the colons of both dogs, but not in an untreated dog. The frequency of ACF increased until month 10, and then decreased. In month 9, very small lesions, less than 1 mm in diameter, which were similar to human early flat tumors, were first noticed. One of these lesions grew to about 7 mm in size without a change in its shape for 10 months. There were more than ten flat-type tumors in the two dogs, but such lesions were not found in the untreated dog. By biopsy, two of the lesions were proved to be well-differentiated adenocarcinomas histologically. Four polypoid lesions were found in one of the carcinogen-treated dogs. Thus, flat-type adenocarcinomas were induced in the dog colon by ENNG, and their development was followed by magnifying endoscopy.

Induction of CYP isoenzymes in various organs of rats by 3-methylcholanthrene or beta-naphthoflavone.

Induction of cytochrome P450 (CYP) isoenzymes in various organs of rats treated with 3-methylcholanthrene (3-MC) and beta-naphthoflavone (BNF) was immunohistochemically and biochemically investigated. Fifteen male F344 rats were divided into three equal groups. Group 1 was untreated as a control. On days 3, 4, 13 and 14, group 2 animals received 3-MC (20 mg/kg body wt i.p.) dissolved in corn oil while group 3 animals were given BNF (50 mg/kg body wt i.p.) dissolved in corn oil, at days 1, 2, 3, 4, 11, 12, 13 and 14. On days 4 and 14, two or three animals in each group were sacrificed, 15 h after administration of the last test compound. Induction of CYP 1A1, 2C11, 2D1, 2E1, 3A2 and 4A1 in various organs was immunohistochemically examined and the levels of CYP 1A1 protein were measured by Western blotting. 3-MC and BNF induced CYP isoenzymes not only in the liver, but also in the small intestine, large intestine, prostate and seminal vesicles. The results indicate that xenobiotic metabolism can occur in various organs.

Emergence of adenomatous aberrant crypt foci (ACF) from hyperplastic ACF with concomitant increase in cell proliferation.

To investigate the relationship between aberrant crypt foci (ACF) and colon neoplasia in colorectal carcinogenesis, we evaluated 433 ACF, which were collected from the grossly normal mucosa of surgical specimens from 57 patients with colorectal cancer. The ACF ranged in size from 3 to 412 aberrant crypts/focus. Large ACF (> or = 50 crypts/focus) comprised 25% of the total ACF studied. Histopathologically, 65% (67 of 103) of large ACF were diagnosed as hyperplasia, 10% (10 of 103) as adenoma, and 1% (1 of 103) as within normal colorectal mucosa. The remaining 24% (25 of 103) were diagnosed as "stage I abnormality crypts," which were characterized by their extension of the proliferative compartment to the surface of crypts but with no changes in the major site of proliferation, as designated by E. E. Deschner [Pathol. Annu., 18 (Part 1): 205-219, 1983]. Of the 25 stage I abnormality ACF, 7 ACF coexisted with hyperplasia. Of 10 adenomatous ACF, two coexisted with stage I abnormality crypts. A K-ras codon 12 mutation was identified in 85% (93 of 109) of large ACF. The proliferative activity of stage I crypts was significantly higher than that of hyperplastic crypts in the same ACF. These observations suggest that some hyperplastic ACF may develop into adenomatous ACF by way of stage I abnormality ACF with concomitant acquisition of higher proliferative activity through some genetic and/or epigenetic changes.