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The number of murine mature blood cells recovered within 6 weeks after 2-Gy whole-body irradiation at 6 weeks of age, whereas in the case of the undifferentiated hematopoietic stem/progenitor cell (HSC/HPC) compartment [cells in the lineage-negative, c-kit-positive and stem-cell-antigen-1-positive (LKS) fraction], the numerical differences between mice with and without irradiation remained more than a year, but conclusively the cells showed numerical recovery. When mice were exposed to radiation at 6 months of age, acute damages of mature blood cells were rather milder probably because of their maturation with age; but again, cells in the LKS fraction were specifically damaged, and their numerical recovery was significantly delayed probably as a result of LKS-specific cellular damages. Interestingly, in contrast to the recovery of the number of cells in the LKS fraction, their quality was not recovered, which was quantitatively assessed on the basis of oxidative-stress-related fluorescence intensity. To investigate why the recovery in the number of cells in the LKS fraction was delayed, expression levels of genes related to cellular proliferation and apoptosis of cells in the bone marrow and LKS fraction were analyzed by real-time polymerase chain reaction (RT-PCR). In the case of 21-month-old mice after radiation exposure, Ccnd1, PiK3r1 and Fyn were overexpressed solely in cells in the LKS fraction. Because Ccnd1and PiK3r1 upregulated by aging were further upregulated by radiation, single-dose radiation seemed to induce the acceleration of aging, which is related to the essential biological responses during aging based on a lifetime-dependent relationship between a living creature and xenobiotic materials. Copyright © 2014 John Wiley & Sons, Ltd.

Background and aim The cytokeratin (CK)7(-) /CK20(+) immunoprofile is characteristic of colorectal carcinoma (CRC), although CK7(+) or CK20(-) phenotypes are occasionally encountered, particularly in histologically variant CRCs. We analyzed CK7/CK20 profiles in variant CRCs in association with clinicopathologic parameters and prognosis. Methods CK expression in well- and moderately differentiated adenocarcinoma (WMDA) (n = 63), poorly differentiated adenocarcinoma (PDA) (n = 91), mucinous adenocarcinoma (MUA) (n = 81), signet-ring cell carcinoma (SRCC) (n = 15), undifferentiated carcinoma (UDC) (n = 12), and adenosquamous carcinoma (n = 2) was analyzed using immunohistochemistry. Cut-off scores were set at 1% for CK7 and 25% for CK20 using the receiver operating characteristic curve analysis of PDA. Association between CK20(-) and better prognosis in PDA was validated in the second cohort (n = 66). Results CK7/CK20 immunoprofiling revealed a predominant CK7(-) /CK20(+) profile in WMDA, MUA, and SRCC, while the majority of UDC was characterized by a CK7(-) /CK20(-) profile. The CK7/CK20 profile in PDA was variable. Contingency table analysis revealed that CK expression was not significantly associated with any clinicopathologic parameters in WMDA, PDA, and MUA. However, survival analysis demonstrated that CK20(-) was significantly associated with better prognosis in PDA. Although CK20(-) was significantly associated with mismatch repair deficiency in PDA, it was an independent prognostic factor in multivariate analysis. Finally, we confirmed that CK20 status, determined using a 25% cut-off score, was a significant prognostic parameter in the second PDA cohort. Conclusions CK20 status may be used as a prognostic predictor of PDA.

Hideki Hirakata, Kosaku Nitta, Masaaki Inaba, Tetsuo Shoji, Hideki Fujii, Shuzo Kobayashi, Kaoru Tabei, Nobuhiko Joki, Hiroki Hase, Masato Nishimura, Shigeyuki Ozaki, Yuji Ikari, Yoshitaka Kumada, Kazuhiko Tsuruya, Shouichi Fujimoto, Tohru Inoue, Hiroyoshi Yokoi, Sumio Hirata, Kazuaki Shimamoto, Kiyotaka Kugiyama, Takashi Akiba, Kunitoshi Iseki, Yoshiharu Tsubakihara, Tadashi Tomo, and Tadao Akizawa

The impact of endocrine disruptors, and specifically the low-dose issue, involves interdisciplinary sciences. Thus, in the past these topics have been published widely in the toxicology area. Owing to recent developments in biology, including the whole-genome reading program, the mechanisms underlying the low-dose issue have been clarified. These mechanisms have been found to involve stochastic and probabilistic receptor-mediated adverse effects induced by endocrine disruptors. The effects thought to be induced by low doses of endocrine-disrupting chemicals remain disputed, and the underlying mechanisms remain poorly understood. Three independent factors, each only recently identified and never before encountered in the history of toxicological studies, are associated with what is termed the ‘low-dose issue’. First, toxicological risk has been estimated only by extrapolation of adverse phenotypes from high-dose effects and thus provides no reliable information on low-dose effects observed at the right time under experimental paradigm with sufficient sensitivity. Second, toxicity is based on disturbances of homeostatic regulation, a largely unexplored area in toxicology. Third, toxicity is based on stochastic and probabilistic xenobiotic response, a new field of toxicology that is specifically linked to low-dose and less-frequent events. To resolve the low-dose issue whether it causes effects or whether effects observed at low-doses should be considered ‘adverse’ – or both, each of these factors needs to be addressed. Copyright © 2010 John Wiley & Sons, Ltd.

The study examined the feasibility of screening for hepatotoxicity by an in vitro gene expression analysis using rat primary hepatocytes and Affymetrix Rat Toxicology U34 arrays. Hepatocytes were exposed for 6 or 24 h to eight drugs, with different mechanisms of hepatotoxicity, at one third of the cytotoxic concentration TC50, i.e. acetaminophen, cyclophosphamide, clofibrate, chlorpromazine, lithocholic acid, cisplatin, diclofenac and disulfiram. The types of transcriptional changes observed in this study were generally consistent with previously reported in vivo data, although there were some differences. In hierarchical cluster analysis, drugs formed clusters depending on their mode of toxicity against cells. The number of transcripts affected by the cholestatic hepatotoxicants (lithocholic acid and chlorpromazine) or the drugs that rarely cause of hepatotoxicity (cisplatin, diclofenac and disulfiram) were limited compared with the other drugs (acetaminophen, clobifibrate and cyclophosphamide), where they did not induce transcriptional changes apparently related to toxicity. It is concluded that in vitro gene expression analysis of hepatocytes using microarray is a useful tool for evaluating the toxicological profile of drugs and in screening for the direct toxicity of drugs against hepatocytes.

Previous fate mapping analysis, using Cre recombinase driven by the Mesp1 locus, revealed that Mesp1 is expressed in almost all of the precursors of the cardiovascular system, including the endothelium, endocardium, myocardium, and epicardium. Mesp1-nonexpressing cells were found to be restricted to the outflow tract cushion and along the interventricular septum (IVS), which is a location that is suggestive of specialized cardiac conduction system (CCS). In our current study, we examined the identity of these IVS cells by using the pattern of beta-galactosidase activity in CCS-lacZ mice. In addition, by crossing Mesp1-Cre and floxed GFP reporter mice with CCS-lacZ mice, we have calculated that approximately 20% of the ventricular CCS within the IVS corresponds to Mesp1-nonexpressing cells. These data suggest that the ventricular CCS is of heterocellular origin. Furthermore, we indicate a possibility that a population of the cells that contribute to the ventricular CCS might be distinguished at an early stage of development.

3-Chloro-4-(dichloromethyl)−5-hydroxy-2(5H)-furanone (MX), a by-product of water chlorination, is a potent bacterial mutagen and rat carcinogen. In the present study, the in vivo mutagenicity, cell proliferative activity, and carcinogenicity of MX were investigated in gpt delta mice. Groups of 5 male and female 7-week-old gpt delta C57BL/6J transgenic mice were given MX at doses of 0, 10, 30, or 100 ppm in their drinking water for 12 weeks, and then killed to assess in vivo mutagenicity using 6-thioguanine and Spi− selection, and cell proliferative activity using immunohistochemistry for proliferating cell nuclear antigen (PCNA). Further groups of 10 male and female gpt delta mice were given 0 or 100 ppm MX for 78 weeks, and a full necropsy with histopathological examination of all organs was conducted to detect neoplastic lesions. The 12-week MX treatment did not result in mutagenicity in the livers or lungs or cell proliferative activity in several organs of the mice, and the 78-week treatment did not cause carcinogenicity. Additional investigations were conducted to evaluate the potential of MX to inhibit gap junctional intercellular communication (GJIC) in rat liver epithelial cells (WB cells) by the scrape loading/dye transfer method. Inhibition of GJIC was detected within 2 hr with a noncytotoxic dose of MX (4 μg/ml), followed by partial restoration after 5 hr. A second phase of inhibition occurred after 10 hr and then the lowered level persisted for the 24 hr-incubation period. Dose-dependent inhibition was evident at both 2 hr and 24 hr, with much stronger effects at the former time. These findings indicate that MX is not mutagenic, mitogenic or carcinogenic in mice, and suggest that the compound exerts epigenetic actions leading to GJIC inhibition. Environ. Mol. Mutagen., 2006. © 2005 Wiley-Liss, Inc.

MSH6 has been implicated in repair of single base mispairs and single-base deletionlinsertion mutations. Established MSH6-null mice present a frequent occurrence of gastrointestinal tumors without microsatellite instability (MI), suggesting the possibility of the APC gene being a mutational target. Because human ampullary carcinomas and gastric cancers manifest frequent missense or I-base deletion mutations in cancer-related genes such as p53 and TGFβ-RII, we suspected that the hMSH6 gene mutation might play a role in the carcinogenesis process. Out of the whole coding sequences, hMSH6 (C) 8 (codons 1085-1087) and hMSH3 (A) 8 repeats (codons 381-383) have been shown to be hotspots for frameshift mutations in a certain group of cancers, contributing to an increased genomic instability. We therefore investigated mutations of hMSH6 (C) 8 and hMSH3 (A) 8 in association with microsatellite mutator phenotype (MMP) in 18 ampullary carcinomas and 30 gastric cancers. In addition, overexpression of the P53 protein and mutational status of APC (AG) 5 (codons 1462-1465) and (A) 6 (codons 1554-1556) repeats were also investigated as a potential target of genetic instability secondary to MSH6 dysfunction. Mutation of the hMSH6 gene was not found in ampullary carcinomas and was irrelevant to TGFβ-RII gene mutation. Mutation of the hMSH6 gene was observed in a subset of gastric cancers (4/30, 13.3%), but was not associated with P53 overexpression or APC gene mutation. In contrast to MSH6-null mice that do not show Ml, hMSH6 gene mutation in human gastric cancers was closely correlated with MMP (3/10 MMP vs. 1/20 non-MMP). In conclusion, hMSH6 mutation appears only in association with MMP and may underlie augmented MI, resulting in missense or I-base frameshift mutations in other genes in human gastric cancers.

Loss of imprinting (LOI) of the igf2 and h19 genes has been found not only in embryonal tumors but also in common adult cancers. To determine any possible role of genomic imprinting in the development of renal-cell carcinomas (RCCs), we examined the imprinting status of igf2 and h19 in a series of 22 such tumors, and studied its relation to their mRNA expression. Of 14 RCC specimens heterozygous for the Apal polypmorphism, 7 (50%) showed LOI of igf2. In contrast, for h19 all 9 informative cases maintained imprinting. Furthermore, all 7 cases with LOI transcribed igf2 mRNA at elevated levels, while H 19 expression was low regardless of the imprinting status compared with that of background level in each case. These results suggest that LOI of igf2, but not of h19, plays a role in the case of human RCC. However, in contrast to that in Wilms' tumor, LOI in RCC was not associated with any specific down-regulation of h19.

Although a close relation of somatic mutations of the adenomatous polyposis coli gene with ampullary carcinomas in familial adenomatous polyposis patients has been reported, the possible association with sporadic ampullary neoplasms has not been fully examined. We have therefore investigated loss of heterozygosity at the adenomatous polyposis coli locus and the mutational status of a portion of the adenomatous polyposis coli gene, including the mutation cluster region, in 17 ampullary carcinomas of non-familial adenomatous polyposis patients. Alteration of the adenomatous polyposis coli gene was found in 8 of 17 (47.1%) cases, as missense or insertion mutations, with or without loss of heterozygosity. Additional investigation of p53 (exons 5-8) and K-ras (codons 12 and 13) gene mutations revealed a striking mutational pattern of the p53 gene. Nine of the 17 cases demonstrated a total of 12 mutations, 6 clustered at codon 189 and 3 at codon 166. Furthermore, 5 of the 12 mutations were nonsense mutations. Regarding the K-ras gene, 4 of the 17 (23.5%) cases had mutations in codon 12, 3 of the 4 cases being derived from the intraduodenal bile duct. The findings indicate that alterations of the adenomatous polyposis coli and the p53 genes are relatively frequent in sporadic ampullary carcinomas. In particular, the clustering at specific p53 codons might offer an etiological clue to clarify ampullary carcinogenesis. Mutations of the K-ras gene, on the other hand, might be characteristic of intraduodenal bile duct origin.

BACKGROUND Several chemotherapy studies have suggested that continuous infusion of 5-fluorouracil (5-FU) is more effective than bolus 5-FU. In addition, 5-FU and cis-Diamminedichloroplatinum-II (cisplatin) in combination have been shown to have synergistic cytotoxicity against several human neoplasms. In this study, the authors evaluated the efficacy and toxicity of continuous infusion of 5-FU and low dose cisplatin infusion (FP therapy) in the treatment of advanced and recurrent gastric adenocarcinoma. The relationship between the response to FP therapy and several factors was also examined. METHODS A total of 26 patients fulfilling standard eligibility criteria were enrolled in the trial. FP therapy consisted of 5-FU (350 mg/m2/day every day by continuous infusion) and cisplatin (7.5 mg/m2/day in 100 mL of normal saline infused over 1 hour on Days 1-5 every week) for 4 weeks. RESULTS A complete response was observed in 2 cases and a partial response in 11 cases, for an overall response rate of 50%. Patients with good performance status (PS) (0-1) and differentiated histologic type showed higher response rates (50.0% and 63.6%, respectively) than patients with poor PS (2 or 3) and undifferentiated histologic type (28.6% and 35.3%, respectively), although there were no significant differences. Patients with low serum levels of immunosuppressive acidic protein (IAP) showed a significantly higher response rate (71.4%) than those with high IAP levels (0%). Toxic effects included leukopenia, thrombocytopenia, nausea, and vomiting; these were not life-threatening and did not require treatment interruption. CONCLUSIONS FP therapy is a promising regimen for patients with advanced and recurrent gastric adenocarcinoma. Serum levels of IAP may predict chemosensitivity. Cancer 1997; 80:1-7. © 1997 American Cancer Society.

Scirrhous gastric carcinoma is characterized by cancer cells that infiltrate rapidly in the stroma with extensive growth of fibroblasts. In the present study, we examined the effect of gastric fibroblasts on the invasiveness of a scirrhous gastric cancer cell line, OCUM-2D, using an invasion assay. Gastric fibroblast-derived conditioned medium (CM) significantly stimulated the invasiveness of OCUM-2D cells, as did transforming growth factor-beta (TGF-beta) and hepatocyte growth factor (HGF). The stimulating activity of gastric fibroblast-derived CM was inhibited significantly by anti-TGF-beta neutralizing antibody or anti-HGF neutralizing antibody. TGF-beta and HGF were detected in the gastric fibroblast-derived CM, and TGF-beta receptor and C-met (HGF receptor) were expressed on OCUM-2D cells. Thus, TGF-beta and HGF produced by gastric fibroblasts appear to affect the invasiveness of scirrhous gastric cancer cells. TGF-beta was also detected in the conditioned medium derived from OCUM-2D cells, though HGF was not. TGF-beta appears to affect the invasiveness of OCUM-2D cells in both paracrine and autocrine fashions.

The role of the adhesion molecule CD44H in the peritoneal adhesion and invasion of cancer cells was assessed using cell lines with low and high peritoneal seeding ability, OCUM‐2M (2M) and OCUM‐2MD3 (2MD3), respectively. The in vitro binding ability to peritoneal components (mesothelial cells, fibroricetin and type I collagen) and invasive ability of 2MD3 cells were higher than those of 2M cells. The expression level of CD44H on 2MD3 cells was higher than that on 2M cells as determined by western blot analysis and flow cytometry. The adhesiveness of 2MD3 cells to hyaluronic acid, which is expressed on the surfaces of mesothelial cells, was greater than that of 2M cells. The binding ability of 2MD3 cells to mesothelial cells was inhibited in the presence of anti‐CD44H monoclonal antibody, but that of 2M cells was not. These results suggested that the 2MD3 cell binding to mesothelial cells is regulated by the CD44‐hyaluronic acid dependent system. The in vitro binding to submesothelial components and the invasiveness of 2MD3 cells were also inhibited in the presence of anti‐CD44H antibody. The in vivo inoculation of 2MD3 cells treated with an anti‐CD44H antibody resulted in a significant prolongation of survival time as compared with control mice that were inoculated with 2MD3 cells alone. In conclusion, CD44H was associated with attachment not only to hyaluronic acid on mesothelial cells, but also to peritoneal stromal components. Thus, CD44H may play an important role in cancer cell binding and invasion in the peritoneal dissemination of scirrhous gastric cancer cells.

Because combined hepatocellular‐cholangiocellular carcinoma is rare and its biological features and pathogenesis have not been well established, we investigated alterations of the p53, K‐ras and Rb‐1 genes, as well as expression patterns of carcinoembryonic antigen and keratin, in seven combined hepatocellular‐cholangiocarcinoinas out of 557 hepatocellular carcinomas autopsied at Tokyo University during 30 years. Mutations of the p53 gene were found in two cases, at codon 244 (GGC to TGC) in the cholangiocellular carcinoma component of case 1 (mixed type, showing an intimate intermingling of both elements) and at codon 234 (TAC to AAC) in both components of case 5 (combined type, consisting of contiguous but independent masses of both elements). Mutation of the K‐ras gene (codon 12, GGT to GAT) was seen only in the cholangiocellular carcinoma component of clinically apparent double cancer, case 6. Allelic alteration of the Rb‐1 gene was observed in two cases, deletion of both alleles in the hepatocellular carcinoma component of case 3 (combined type) and replication error of the same pattern in both components of case 4 (mixed type). Immunohistochemical analysis showed that the hepatocellular carcinoma components of five cases (cases 2, 3, 5, 6, 7) were immunoreactive for keratin, suggesting biliary epithelial transformation. In four of the five cases (cases 3 and 5 combined, case 7 mixed and case 6 double cancer), cholangiocellular carcinoma components were also positive for keratin. These results suggest that both components of combined hepatocellular‐cholangio‐carcinoma have the same genetic and phenotypic character and might have arisen from the same origin in some cases.

Ferric nitrilotriacetate (Fe‐NTA) is a renal toxicant and carcinogen in rats and mice. We found that its administration results in formation of 4‐hydroxy‐2‐nonenal (HNE) in the renal proximal tubule cells of rats, and 8‐hydroxydeoxyguanosine (8‐OHdG) adducts in their DNA, suggesting a role for oxidative stress. Since 2‐mercaptoethane sulfonate (MESNA) and N‐acetylcysteine (NAC), administered orally, have been shown to increase the kidney levels of free thiol groups, their influence on the renal toxicity and carcinogenicity induced by Fe‐NTA was examined in the present study. Male Wistar rats were intraperitoneally injected with Fe‐NTA (12 mg Fe/kg), and MESNA (100 mg/kg) or NAC (200 mg/kg) was given orally 1 h before and 1 h after this treatment. The animals were killed for tissue analyses 3 h after the Fe‐NTA exposure. In accord with our previous reports, HNE‐modified protein was detected in the proximal tubules of Fe‐NTA‐treated rats by means of immunohistochemistry. Likewise, levels of 8‐OHdG in the renal nuclear DNA, lipid peroxides as thiobarbituric acid‐reactive substances in the kidneys, and blood urea nitrogen and creatinine in the serum were significantly increased by the Fe‐NTA treatment. All of these changes were completely inhibited by oral administration of MESNA or NAC. These results suggest that both of these compounds can prevent the oxidative stress induced by Fe‐NTA.

BACKGROUND Peritoneal metastases are one reason for the poor prognosis of scirrhous gastric cancer. However, the mechanism of peritoneal metastasis remains unclear. We therefore investigated the interaction between gastric cancer cells and peritoneal fibroblasts, in vivo and in vitro. METHODS A human scirrhous gastric cancer cell line, OCUM-2MD3, and a human peritoneal fibroblast cell line, NF-2P, were established in our laboratory. We then investigated the effect of OCUM-2MD3 cells on the peritoneum of nude mice and on the proliferation of NF-2P cells, the effect of NF-2P cells on the migratory capability of OCUM-2MD3 cells, and the effect of peritoneal fibrosis on the development of peritoneal metastasis. RESULTS The proliferation of peritoneal fibroblasts was recognized in areas with and without cancer cell infiltration. Serum-free conditioned medium from the OCUM-2MD3 cells had induced peritoneal fibrosis in vivo and significantly stimulated the proliferation of NF-2P cells in vitro. The molecular weight (molecular weight ratio 25,000–43,000) of the growth factors produced by the OCUM-2MD3 cells was estimated by gel filtration high performance liquid chromatography. The migratory capability of the OCUM-2MD3 cells was significantly increased by the presence of NF-2P cells. Tumorigenicity in mice with peritoneal fibrosis was greater than in mice with normal peritoneum. CONCLUSIONS Peritoneal fibrosis, formed by a factor secreted by scirrhous gastric cancer cells, may be a congenial environment (“soil”) for peritoneal metastases of scirrhous gastric carcinoma. Cancer 1996;77:1676-80.

Background. The relationship between the DNA synthetic activity of hepatocytes from cirrhotic liver tissue and the incidence of hepatocellular carcinoma (HCC) during a 3-year follow-up period was studied in male and female patients with posthepatitic cirrhosis. Methods. The bromodeoxyuridine labeling index (BrdU LI) of hepatocytes was estimated in 38 cirrhotic patients (Child A stage, 23 men and 15 women) using a BrdU/anti-BrdU in vitro method. The incidence of HCC was compared between male and female cirrhotic patients during a 3-year follow-up period. Results. Sixteen of 23 (69.6%) male patients belonged to the high-DNA synthesis group (BrdU LI ⩽ 1.5%), and only 7 (30.4%) were in the low-DNA synthesis group (BrdU LI < 1.5%). Among female patients, only 5 of 15 (33.3%) were in the high-DNA synthesis group, and 10 of 15 (66.7%) were in the low-DNA synthesis group (P < 0.05). Eleven of 23 (47.8%) male patients and 3 of 15 (20.0%) female patients had HCC develop. In the high-DNA synthesis group, 10 of 16 (62.5%) of the men and 3 of 5 (60.0%) of the women had HCC develop during the follow-up period. In contrast, only one of seven (14.3%) male patients and none of ten (0%) female patients in the low-DNA synthesis group had HCC develop. Conclusions. It was concluded that HCC developed frequently (about 60% of the time within 3 years) in patients of both sexes who were in a high-DNA synthesis group. Thus, the larger proportion of men in the high-DNA synthesis group compared with the number of women in the group (69.6% versus 33.3%) might be one possible reason for the male predominance in the development of HCC in cirrhotic patients.

BACKGROUND There is a concept that a cancer often maintains some of the traits of the background tissue cells. Thus, the possibility exists that the DNA synthetic activity of the hepatocytes in cirrhotic tissue affects that of hepatocellular carcinoma (HCC) cells. METHODS DNA synthesis activity of hepatocytes from background cirrhotic tissue and HCC cells from cancerous tissue was studied in 30 patients with liver cirrhosis (LC) and HCC who had undergone hepatectomy; the study was done using the bromodeoxyuridine (BrdU)-anti-BrdU in vitro method. The correlation between the BrdU labeling index (LI) of hepatocytes from noncancerous cirrhotic tissue and that of HCC cells was studied. The relationship between both BrdU LI values and the survival after hepatectomy also was studied. RESULTS A significant correlation (r = 0.572; P < 0.001) was identified between the BrdU LI for HCC and that for noncancerous cirrhotic tissue. A significant correlation (r = -0.572; P < 0.05) was found between the BrdU LI of HCC cells and the survival after hepatectomy. A significant correlation (r = -0.678; P < 0.01) was observed between the BrdU LI of the noncancerous cirrhotic tissue and the survival. CONCLUSIONS It was concluded that a significant correlation existed between DNA synthesis of hepatocytes from the background cirrhotic tissue and that of HCC cells and that DNA synthesis activity of hepatocytes from noncancerous cirrhotic tissue and that of HCC cells from cancerous tissue could predict the survival of patients with HCC who had undergone hepatectomy.

We have successfully constructed the tetracyclic skeleton of lysergic acid, which features an acylation at the C3 position of the indole as well as an intramolecular Heck reaction. The optically active D ring unit could be derived from L-pyroglutamic acid via a disrotatory electrocyclic reaction of a dibromocyclopropane.

We observed GST‐P‐positive liver foci in rats during the course of developing liver cirrhosis by oral administration of furfural, an organic solvent. Male Wistar rats were given furfural‐containing diet (20–30 rag/kg diet) for 15–150 days, and killed 14 days after terminating furfural feeding. Immuno‐histochemical investigation of GST‐P‐positive liver foci which appeared in rats fed furfural for more than 30 days revealed an increase in number and size of the foci in proportion to the duration of furfural administration. Since furfural is known not to be carcinogenic in rats, this finding will be helpful to understand the enhancing effect of furfural‐induced cirrhosis on chemical hepatocarcino‐genesis.

An unusual case of primary reticulosis of the bone marrow in a 67-year-old female has been described. Pathological-anatomical characteristics of the present case are as follows; 1) Primary non-destructive proliferation of neoplastic reticulum cells or their variants, confined to the systemic bone marrow. Metastatic foci were noted in several areas where extramedullary hematopoiesis occurred. 2) Cytologically, neoplastic cells resemble atypical plasmacytic cells. No active phagocytosis was noted in neoplastic cells. 3) Histologically a significant increase in reticulin fibers was observed closely associated with proliferating cells. 4) Electron-microscopically these cells showed developed endoplasmic reticula but were distinguishable from myeloma cells by their irregular cytoplasmic border, which became frequently obscure, and by the presence of a desmosome-like structure. 5) These cells showed a negative immunofluorescent reaction to all types of human immunoglobulin classes. The morphological characteristics of these cells distinguished the disorder from poorly differentiated myelomatosis.

Different types of tumors developed in transgenic mice following the introduction of the entire coding region of ras, myc or SV40 large T gene (T) linked to the same regulatory unit, consisting of a human immunoglobulin gene enhancer (Ig) and SV40 early gene promoter (Tp) with a 21-bp repeat. All the 12 transgenic mice harboring the intact T gene developed a variety of tumors including choroid plexus tumor, B cell lymphoma, histiocytic lymphoma, thymoma and others. This suggests that the Ig/Tp regulatory unit has transcriptional activity in these heterologous tissues. With this regulatory unit, myc gene induced solely pre-B cell lymphomas (five out of nine mice). Contrary to our expectation, however, the mutated ras gene induced lung adenomatous tumors in six out of eight transgenic mice over the 10-month observation period; the tumors are histologically comparable to adenocarcinomas in man. The tumors developed as early as 4 weeks after birth and the introduced ras gene was as efficiently expressed in both normal and neoplastic bronchioloalveolar epithelial cells as in normal lymphoid cells. An unidentified secondary event thus appears to be necessary for these ras-expressing cells to become neoplastic, as observed for myc (Leder et al., 1986). In a variety of tumors induced by Ig/Tp-T, on the other hand, T gene was expressed only in the tumor cells, but not in normal cells. Thus, derepression of T gene in normal cells appears to be closely related to their malignant change as observed in development of pancreatic acinar cell tumors by the T gene (Ornitz et al., 1985). These results suggest that ras and myc oncogenes penetrate differentially specific types of cells, while the SV40 T gene is tumorigenic in a variety of cell types.

An autopsy case of "lipomatous hypertrophy of the cardiac interatrial septum" (LHIS) combined with marked stenosis and calcification of the aortic and mitral valves due to fibrous valvular endocarditis, malignant lymphoma, and mucin-producing cancer of the pancreas is reported. LHIS and mucin-producing cancer of the pancreas were incidental findings at autopsy. Microscopically, the LHIS in this case consisted of proliferation of mature fat cells, brown fat cells and cardiac muscle cells. Since these three cell types are normal structural components of the interatrial septum, it was considered that the LHIS was a hamartomatous rather than hypertrophic lesion, of the cardiac atrial septum. Accordingly it was concluded that the term "lipomatous hamartoma of the cardiac atrial septum" was more appropriate for this lesion in the case presented here. As far as we know, this is the first reported case of LHIS in Japan.

An autopsy report of a 76 years old Japanese male, who had suffered from gamma- HCD, was presented. This is the fifth case of gamma-HCD in Japan and this communication is the first autopsy report made on gamma-HCD in our country. The primary pathological alteration of this disorder is a neoplastic proliferation of atypical lympho-plasmacytes extending throughout the entire hematopoietic and parenchymatous organs. Pathological characteristics of our case were compared with the same disorders reported in the world literatures.

With the aim of examining increasing deoxyribonucleic acid (DNA) synthesis of liver cirrhotic tissue when hepatocellular carcinoma (HCC) is developing, bromodeoxyuridine labeling indices (BrdU LI) of liver biopsy specimens from 19 control cirrhotic (control LC) patients without HCC, 19 cirrhotic patients with HCC, and from six control subjects were examined using an in vitro labeling technique. The mean BrdU LI +/- SD of HCC cancerous portion, HCC non-cancerous cirrhotic portion, control LC, and of control subjects were 7.2 +/- 2.9%, 3.3 +/- 1.5%, 2.1 +/- 1.7%, and 0.25 +/- 0.09%, respectively. Interesting enough, there was a significant difference (P less than 0.05) between the non-cancerous cirrhotic portion and control LC. Although all 17 non-cancerous cirrhotic portion belonged to the high LI group (greater than or equal to 1.5%), 10 of 19 in the control LC belonged to the low LI group (less than 1.5%) (P less than 0.001). The authors conclude that HCC would develop in the cirrhotics with high DNA synthetic potency.

Eight-to-twelve-week-old male and female C57B1/6 BNL mice were exposed to air or benzene vapor in air at a concentration of 10, 25, 100, 300, or 400 ppm. Benzene at concentrations of 100 ppm or higher for 10 exposures of 6 hours per day 5 days a week produced a reduction in bone marrow cellularity and the number of pluripotent stem cells in the bone marrow. The fraction of stem cells in DNA synthesis was also increased. Exposure to 300 ppm 6 hours a day 5 days a week for 2, 4, 8, and 16 weeks produced a diminution in the stem cell levels in bone marrow which returned to those of controls 2 weeks after benzene exposure for 2 and 4 weeks, 16 weeks after exposure for 8 weeks, and to 92% of controls 25 weeks after 16 weeks of exposure. There was a more rapid return of blood lymphocytes to the control level. Mice exposed to 300 ppm for 6 hours/day, 5 days per week for 16 weeks began dying at 330 days of age, whereas no deaths were observed in sham-exposed mice until 440 days of age. The benzene-exposed mice died in two waves: the first was from 330-390 days of age, with a second wave commencing at 570 days of age. The first wave of mortality was due primarily to thymic lymphomata. The second wave was due to a mixture of nonthymic lymphomata and solid tumors.

The catalytic effect of the mixed micelles of lauroylamino acids (LauAm) and detergents on the hydrolysis of p-nitrophenyl acetate has been studied. The amino acids used for the synthesis of LauAm were glycine, serine, histidine, tyrosine, lysine, and arginine. Cetyltrimethylammonium bromide (CTAB), polyoxyethylene dodecyl ether (C12E6) and sodium dodecyl sulfate (SDS) were used for the preparation of the mixed micelles with LauAm. Among the detergents used, only CTAB remarkably enhanced the catalytic activity of LauAm. A reaction scheme was proposed, and the rate constant for the catalytic activity of LauAm was estimated from the kinetic data. The effect of pH was also studied. Discussions were given of the mechanism of the catalytic action on the basis of the present study.