Biomedical subjects

N Takeichi

Publications and source records attributed to N Takeichi.

At least 73 records · Page 4Linked to original sources

PubMed1994

ONO-4007, a new synthetic lipid A derivative, induces differentiation of rat myelomonocytic leukemia cells in vitro and in vivo.

We have examined the differentiation-inducing effects of ONO-4007, a new synthetic lipid A derivative with low endotoxic activities, on a rat myelomonocytic cell line, c-WRT-7, in vitro and in vivo. ONO-4007 induced the differentiation of c-WRT-7 cells into macrophage-like cells and inhibited the proliferation of c-WRT-7 cells in vitro. Stimulation with ONO-4007 induced messenger RNA expression of interleukin-1 alpha (IL-1 alpha), IL-6, and tumor necrosis factor-alpha (TNF-alpha), which have been reported to induce differentiation of several leukemia cell lines. However, autocrine production of these cytokines may not be involved in the mechanisms of differentiation induced by ONO-4007, because the treatment with IL-1 alpha, IL-6, or TNF-alpha does not induce the differentiation of c-WRT-7 cells. In vivo treatment by intravenous administration of ONO-4007 resulted in a significant prolongation of survival time of the rats inoculated intravenously with c-WRT-7 cells compared with that of untreated rats. These results suggest that ONO-4007 can be therapeutically useful for the treatment of leukemia.

Alkaloids↗

PubMed1994

Point mutation of aldehyde dehydrogenase-2 gene in mutant strains of Long-Evans rats.

Long-Evans Cinnamon (LEC) and Long-Evans Agouti (LEA) rats are mutant strains established from Long-Evans rats. LEC rats display hereditary hepatitis and spontaneous hepatocellular carcinoma, but LEA rats do not develop liver diseases. We previously demonstrated that LEC rats had an impairment of liver aldehyde dehydrogenase (ALDH) activities, and all LEC rats which were fed with a liquid diet containing 5% ethanol died within 2 weeks. In the present study, we also found that LEA rats could not metabolize ethanol and died after being fed the same diet. Remarkably, in the liver of LEA rats, low Km ALDH activities were suppressed as much as in LEC rats. These results suggested that both LEC and LEA rats have hereditary deficiencies in ALDH. Nucleotide sequence analysis of ALDH2 genes in both LEC and LEA rats demonstrated that the point mutation of the codon for residue 67 encoding Gln to Asp was observed; this was not so in either Long-Evans rats or Wistar rats. This mutation in ALDH2 genes may cause inactivation of ALDR activity in LEC and LEA rats.

Aldehyde Dehydrogenase↗

PubMed1993

Lack of copper binding sites in ceruloplasmin of LEC rats with abnormal copper metabolism.

Recently it was found that the clinical features of the LEC rat closely resemble those of human Wilson's disease. One of the characteristics of the animal is low levels of serum ceruloplasmin. Therefore, by using LEC rats, we attempted to define molecular basis of the deficiency in active site of ceruloplasmin in Wilson's disease patients. We made 3 monoclonal antibodies, ID2 against active site of ceruloplasmin, ID1 against inactive site of ceruloplasmin, and the remaining one against metallothionein. Using these monoclonal antibodies, we examined immunohistochemical stainings of LEC rat liver tissues, and compared them with those of LEA rats, as a control. ID1 stained the hepatocytes of both LEA and LEC rats, whereas ID2 stained LEA rat hepatocytes only. The results indicated that the ceruloplasmin secreted by LEC rat hepatocytes is mostly in inactive form. The antibody against metallothionein stained LEA rat hepatocytes only. This finding may also indicate that LEC rat hepatocytes express less amount of metallothionein than those of LEA rats.

Animals↗

PubMed1993

[MR images of the hepatocellular carcinoma in Long-Evans cinnamon (LEC) rats].

Long-Evans Cinnamon (LEC) rats which have an abnormal copper accumulation in the liver develop hereditary hepatitis and subsequent hepatocellular carcinoma (HCC). We studied the correlation of MR images of the HCCs developed in LEC rats and histopathological features. The HCCs of LEC rats had high intensity on T 1-weighted images and iso-low intensity on T 2*-weighted images. Histopathological examination showed that the HCCs were highly differentiated. Copper concentration in the HCCs was lower than that in the surrounding non-cancerous liver tissues. From these results, we suggest that copper accumulation may not be responsible for the high intensity of HCCs on T 1-weighted images.

Animals↗

PubMed1993

Selective removal of copper bound to metallothionein in the liver of LEC rats by tetrathiomolybdate.

LEC rats (Long-Evans with a cinnamon-like coat color) have a genetical defect in Cu metabolism. Male LEC rats aged 10 weeks were injected ip with TTM at a dose of 5 or 10 mg/kg body weight for 8 consecutive days and killed one day after the last injection. Cu that had accumulated in the liver at a concentration of 251 micrograms/g liver was decreased to 82.7 or 74.3 micrograms/g liver respectively, by the treatment. Although most of Cu was bound to MT as a soluble form before TTM treatment, the metal remaining in the liver after the treatment was present almost exclusively in the non-soluble fraction. Zinc (Zn) present, bound to MT before the treatment, was also partly removed from the liver by TTM, and the Zn remaining in the liver after the treatment was revealed to be bound to MT (Zn-MT) by high performance liquid chromatography-atomic absorption spectrophotometry. Iron (Fe) in the liver was not affected by TTM treatment. Cu in the kidneys and spleen increased by TTM treatment, while Zn and iron were not affected. Treatment of LEC rats with severe jaundice effectively cured the animals from otherwise lethal signs by only two ip injections of TTM at a dose of 10 mg/kg body weight.

Animals↗

PubMed1993

Histochemical demonstration of copper in LEC rat liver.

Livers of LEC rats were histochemically stained for copper according to the modified Timm's method, which includes trichloroacetic acid (TCA) treatment. TCA pretreatment was effective in removing zinc and iron, leaving as the major metal in the liver. Hepatocytes in 3-month-old rats were stained intensely by the modified Timm's method, both in frozen sections and in paraffin-embedded specimens. The centrilobular hepatocytes were usually stained, but positive cells were also randomly distributed in the hepatic lobes, showing a mosaic pattern. The staining was intensified in 8- compared to 3-month-old LEC rats. In contrast hepatocytes from LEA rats, the normal counterpart of LEC rats, were faintly stained for copper. Proliferating cholangioles found in older LEC rats were shown to lack copper deposition, and hepatocellular carcinoma showed less copper deposits than the hepatocytes surrounding the tumor. The copper staining was augmented in livers of LEC rats subjected to copper-loading, but was less intense in the livers treated with D-penicillamine. The staining intensity under the various experimental conditions showed good correlation with the copper concentration. Lysosomal deposition of copper in hepatocytes was demonstrated by electron microscopic analysis for copper. Thus the modified Timm's method was shown to produce valuable results in demonstrating copper in LEC rat livers, providing important information for an understanding of the mechanism of copper deposition and hepatic disease of the animal.

Animals↗

PubMed1993

Differentiation of the rat myelomonocytic leukemia cell line c-WRT-7 by in vitro culture with the rat bone marrow preadipocyte cell line REC A16.

Differentiation of the rat myelomonocytic leukemia cell line (c-WRT-7) was investigated, by co-culture with a rat embryonic bone marrow preadipose cell line (REC A16). Co-cultivation with REC A16, or with conditioned medium from REC A16 cultures (REC-CM), induced differentiation of c-WRT-7 cells to macrophages. A soluble factor(s) produced by REC A16 appeared to be responsible for the differentiation of c-WRT-7. Because REC-CM was associated with colony-stimulating activity on murine marrow progenitors, c-WRT-7 cells were cultured with various colony-stimulating factors (CSF) and it was found that macrophage CSF (M-CSF) significantly induced differentiation of c-WRT-7. We further demonstrated that both the colony-stimulating and differentiation-inducing activities of REC-CM were significantly blocked by anti-M-CSF antiserum. These results suggest that the differentiation of c-WRT-7 is due to M-CSF produced by REC A16. Co-culture of these two cell lines should provide a useful model to study the mechanisms of interaction between leukemia cells and marrow stroma.

Animals↗

PubMed1993

Abnormal ethanol metabolism in Long-Evans Cinnamon rats, a mutant strain developing spontaneous hepatoma.

The Long-Evans Cinnamon (LEC) rat is a mutant strain established from Long-Evans rats. LEC rats display hereditary hepatitis and spontaneous hepatocellular carcinoma (HCC). We first tried to examine effects of ethanol consumption on the development of HCC, and fed a Lieber's liquid diet containing 5% ethanol to LEC rats. However the rats died within 2 weeks because of acute alcohol intoxication. In LEC rats, the concentration of ethanol and acetaldehyde in blood was significantly higher, and liver alcohol dehydrogenase activity was slightly lower and acetaldehyde dehydrogenase activities were remarkably suppressed compared to those of Wistar rats. These results suggest that LEC rats have hereditary deficiencies of ethanol and acetaldehyde metabolizing enzymes.

Acetaldehyde↗

PubMed1993

Magnetic resonance imaging of hereditary spontaneous hepatitis in Long-Evans cinnamon rats.

RATIONALE AND OBJECTIVES: Long-Evans Cinnamon (LEC) rats have abnormal metal metabolism and spontaneously develop hereditary hepatitis. The influence of in-vivo metals on magnetic resonance imaging (MRI) was studied using LEC rats. METHODS: Short spin-echo images of the livers of LEC rats were obtained using a 7.05-T small-bore MR unit. Effectively, these images were proton-density images because of T2-shortening mechanism in high magnetic field. The LEC rats were imaged during pre-, acute, and chronic hepatitis phases. The accumulation of copper and iron in the livers of LEC rats was evaluated. RESULTS: Signal intensities, which were homogeneous throughout the liver in every phase, decreased in the acute hepatitis phase and recovered in the chronic hepatitis phase. Copper was accumulated in all phases. Iron was observed grossly in the hepatocytes in the acute phase, but decreased in the chronic phase. CONCLUSIONS: Signal intensities of proton-density images of the livers of LEC rats in phases of pre-, acute, and chronic hepatitis were influenced by iron.

Acute Disease↗

PubMed1993

Elevated level of 8-hydroxydeoxyguanosine in DNA of liver, kidneys, and brain of Long-Evans Cinnamon rats.

Long-Evans Cinnamon (LEC) rats, a mutant strain originating from Long-Evans rats, spontaneously develop hereditary hepatitis followed by hepatocellular carcinoma. The hepatic disorder in LEC rats is associated with their abnormal copper metabolism; metal-catalyzed reactions often give rise to oxygen radicals, which may be related to the carcinogenesis. By means of high-pressure liquid chromatography with electrochemical detection, cellular DNA damage caused by oxygen radicals can be assessed in terms of the amount of 8-hydroxydeoxyguanosine (oh8dG). We assayed the amount of oh8dG in DNA of liver, kidneys, and brain of LEC and Long-Evans Agouti (LEA) control rats in seven groups (n = 3 to 6) aged from 5 weeks to 24 months. Control rats, a healthy sibling line, were age-matched. The amount of oh8dG was correlated with the severity of the age-related clinical symptoms in LEC rats. The amount was higher in LEC rats than in the controls, especially in the liver at the acute stage of hepatitis. These findings suggest that oxygen radicals may be important in the carcinogenesis that occurs in LEC rats.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1993

Enhancement of tumorigenicity and invasion capacity of rat mammary adenocarcinoma cells by epidermal growth factor and transforming growth factor-beta.

We have studied the effects of growth factors and cytokines on the tumorigenicity and invasion capacity of tumor cells by using regressor and progressor tumor cell lines (ER-1 and ERpP, respectively) derived from an SHR rat mammary adenocarcinoma. ER-1 cells regress spontaneously whereas ERpP cells show invasive growth and high metastasis to lung and other organs in syngeneic SHR rats. When ER-1 cells were pretreated with either epidermal growth factor (EGF) or transforming growth factor-beta (TGF-beta) for 24 h in vitro, and intraperitoneally transplanted into SHR rats, they grew and killed the host, whereas ER-1 cells pretreated with tumor necrosis factor-alpha did not. Tumorigenicity and invasion capacity of ERpP cells were also enhanced by treatment with EGF and TGF-beta. The ER-1 cells pretreated with EGF, once grown in vivo, had acquired irreversible tumorigenicity and invasion capacity without requiring further EGF treatment, and the enhanced malignancy was irreversible. These findings suggest that growth factors play an important role in acquisition of malignancy of tumor cells.

Adenocarcinoma↗

PubMed1993

Progression of a weakly tumorigenic mouse fibrosarcoma at the site of early phase of inflammation caused by plastic plates.

To elucidate tumor progression-enhancing factor(s), we examined the effects of host inflammation and host immunological status on in vivo tumor progression. One x 10(4) cells of QR clones (QR-32, -20 and -18), regressor tumor clones of 3-methylcholanthrene-induced fibrosarcoma, were unable to grow when injected s.c. into C57BL/6 mice in cell suspension form. However, QR clones grew and were lethal when s.c. implanted, attached to plastic plates. Furthermore, the tumor lines (QRpP) obtained from the tumors which had arisen from the plate-attached QR-32 clone cells no longer required plastic plates for their growth in normal mice, and had acquired stable malignant phenotypes. Although QR-32 cells became lethal when injected at the site of plastic plate implantation 1, 5 and 10 days before tumor injection, few tumors developed when plastic plates had been implanted 20 or 30 days before tumor injection. We established culture clones from the tumors arising in normal mice and mice immunosuppressed by irradiation. Clones derived from the tumors which had arisen in normal mice after implantation with plastic plates were lethal when re-implanted in normal mice (71%). On the other hand, clones derived from the tumors that arose in irradiated mice with or without plastic plates were lethal in only a few normal mice, when re-implanted (20 and 8%, respectively). These results indicate that QR clone cell progression is enhanced by the early phase of inflammation at the site of plastic plate implantation and that the progression-enhancing activity of co-implantation with a plastic plate is inhibited by previous whole-body irradiation of hosts.

Animals↗

PubMed1993

Abnormal hepatic iron accumulation in LEC rats.

The LEC (Long-Evans cinnamon) rat is a mutant strain displaying hereditary hepatitis and spontaneous hepatocellular carcinoma, and shows abnormal hepatic copper accumulation similar to that occurring in Wilson's disease. We evaluated the iron metabolism of LEC rats compared to LEA (Long-Evans agouti) rats. Hepatic iron and ferritin concentrations were remarkably increased depending on age in LEC rats but not in LEA rats. Increased hepatic iron is normally associated with decreased serum transferrin and total iron binding capacity in hepatic iron overload. In LEC rats, however, both serum transferrin and total iron binding capacity increased with increasing hepatic iron. This increase of serum transferrin and hepatic iron may be an additional important factor contributing to liver injury in LEC rats.

Age Factors↗

PubMed1993

Prevention of spontaneous hepatocellular carcinoma in Long-Evans cinnamon rats with hereditary hepatitis by the administration of D-penicillamine.

Acute hepatitis spontaneously develops in the Long-Evans Cinnamon rat at the age of 4 mo, and eventually hepatocellular carcinoma develops after the chronic hepatitis that persists for over a year. Previously, abnormal copper accumulation was found in the livers of Long-Evans Cinnamon rats from birth, and it was reported that short-term administration of D-penicillamine, a copper-chelating agent, prevented acute hepatitis in Long-Evans Cinnamon rats. In this study we investigated whether long-term administration of D-penicillamine could also prevent chronic hepatitis and subsequent hepatocellular carcinoma in Long-Evans Cinnamon rats. During long-term observation, which was continued from 11 to 70 wk after birth, no elevation of serum transaminase levels was observed in the Long-Evans Cinnamon rats treated with D-penicillamine. Moreover, no histological changes characteristic of the chronic hepatitis were observed in D-penicillamine-treated Long-Evans Cinnamon rats, which were killed at 70 wk of age. Furthermore, placental glutathione S-transferase-positive foci, described as a marker for preneoplastic lesions in the liver, were not detected, and thus hepatocarcinogenesis was completely prevented in D-penicillamine-treated Long-Evans Cinnamon rats. We also found that the amount of 8-hydroxy-deoxyguanosine, one of oxidative DNA damage products in the liver, was decreased in the Long-Evans Cinnamon rats treated with D-penicillamine. These findings suggest that a process of the prolonged liver-cell injury and regeneration was essential for spontaneous development of hepatocellular carcinoma in Long-Evans Cinnamon rats with abnormal copper metabolism.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1993

[Enhanced malignancy of tumor cells by the interaction with host cells reactive to foreign body].

We examined factors promoting malignant progression using a weakly malignant variant cell line, ER-1, derived from c-SST-2, a rat mammary carcinoma. ER-1 cells were converted to a highly malignant phenotype (highly tumorigenic, metastatic, invasive in vitro) by the in vitro/in vivo interaction with host cells reactive to foreign body. Epidermal growth factor (EGF) and transforming growth factor-beta (TGF-beta) produced by host reactive cells, transiently enhanced the tumorigenicity and in vitro invasiveness of ER-1 cells into an endothelial cell monolayer. The host reactive cells also produced oxygen radicals and induced mutations in ER-1 cells. It is speculated that mutations induced by host reactive cells cause cellular diversification, including the emergence of highly malignant variant cells whose growth is selectively promoted by growth factors such as EGF and TGF-beta.

Animals↗

PubMed1992

Regional distribution of copper, zinc and iron in the brain in Long-Evans Cinnamon (LEC) rats with a new mutation causing hereditary hepatitis.

In Long-Evans Cinnamon (LEC) rats of three different ages (7, 13 and 32 weeks old) concentrations of Cu, Zn and Fe were measured in 8 regions of the brain. The LEC groups aged 7 and 13 weeks showed low concentrations of Cu in all regions compared to Long-Evans Agouti (LEA) rats. In 32-week-old LEC rats, however, Cu concentrations increased in 7 regions, in particular, significantly so in the striatum, hypothalamus, cerebellum, midbrain and cortex. Changes of Zn concentration were not found in any region. The Fe concentration increased in cortex and olfactory lobes. The three LEC groups showed a very high concentration of hepatic Cu and a low concentration of serum Cu compared to LEA rats. In LEC rats aged 32 weeks, however, hepatic Cu decreased and serum Cu increased compared to the other two LEC groups. These results suggest that the increase of the cerebral Cu concentration is closely related to the inherently abnormal Cu metabolism and then to the changes of Cu metabolism from about 13 weeks after birth.

Animals↗

PubMed1992

Comparison of disposition behavior and de-coppering effect of triethylenetetramine in animal model for Wilson's disease (Long-Evans Cinnamon rat) with normal Wistar rat.

The disposition behaviors and de-coppering effect of triethylenetetramine dihydrochloride (trientine), a selective chelating agent for copper and an 'orphan drug' for Wilson's disease, have been evaluated in an animal model, Long-Evans Cinnamon (LEC) rats, and normal rats (Wistar). In LEC rats, urinary excretion of trientine was remarkably lower than that of Wistar rats. The absorption rates from the jejunal loop and in vitro metabolism in the liver S9 fraction (supernatant of 9000 x g) were approximately the same for both strains. The decline of urinary excretion of trientine in LEC rats is thought to be due mainly to the lowering of the functional activity of the kidney, because urinary excretion of creatinine and phenolsulfonphthalein were significantly lower in LEC rats than those in Wistar rats. Both acceleration of urinary excretion of copper and reduction of hepatic copper levels were observed with treatment of trientine in LEC rats aged 6 weeks. In LEC rats aged 13 weeks, however, no de-coppering effect from the liver was observed, though urinary excretion of copper was increased. These results suggest that trientine has a pharmacological effect in disease state, especially in the early stages of hepatitis.

Animals↗

PubMed1992

D-penicillamine prevents the development of hepatitis in Long-Evans Cinnamon rats with abnormal copper metabolism.

The Long-Evans Cinnamon rat is a mutant strain that contracts hereditary hepatitis and, eventually, spontaneous hepatocellular carcinoma. Because we found a corresponding gross copper accumulation in the liver of the rats, we examined whether the development of hepatitis in our rat system could be prevented by administration of D-penicillamine. D-Penicillamine is a copper-chelating agent and one of the drugs effective for human Wilson's disease, in which abnormal copper metabolism is also observed. The results show that D-penicillamine treatment inhibited the elevation of serum transaminases, suppressed abnormal histological changes in the liver and completely prevented the onset of hepatitis in the Long-Evans Cinnamon rats. We further found that the copper concentration in the liver and serum copper and ceruloplasmin levels were decreased, whereas the urinary copper level was increased in the D-penicillamine-treated Long-Evans Cinnamon rats. These findings demonstrate that the pathogenesis of hereditary hepatitis in Long-Evans Cinnamon rats is due to abnormal copper accumulation in the liver.

Alanine Transaminase↗