Lysosomes of rat liver and dab carcinogenesis

The relationship between DAB carcinogenesis and changes of lysosomes in rat liver was investigated. After 40 days of treatment with DAB, nodules and an abnormal cell population, containing small, large and degenerative cells, appeared. Corresponding to these changes, the S/P ratio of lysosomal enzymes such as acid RNase and β-glucuronidase increased to two or three times the normal value. These alterations were considered along with some histochemical observations on β-glucuronidase. A possible participation of these lysosomal enzymes in carcinogenesis is discussed.     

Functional genomics may allow accurate categorization of the benzimidazole fungicide benomyl: lack of ability to act via steroid-receptor-mediated mechanisms

Although benomyl and its metabolite carbendazim have been shown to adversely affect male reproduction, the mechanisms of action do not appear to involve the endocrine system. However, few studies have been conducted using currently proposed tests specifically focused on endocrine disruption. Here, potential estrogen- and androgen-mediated activity of benomyl was therefore investigated in vitro and in vivo. Benomyl and carbendazim proved negative for agonistic and antagonistic activity in reporter gene assays for the human estrogen receptor alpha and androgen receptor. In uterotrophic and Hershberger assays using Crj:CD(SD)IGS rats, benomyl (100, 300 or 1000 mg/kg/day, p.o., N = 6) did not exert agonistic effects. However, the highest dose decreased uterine weights in the uterotrophic assay, and decreased weights of some androgen-related tissues of castrated rats receiving a testosterone propionate (TP, 0.2 mg/kg) injection in the Hershberger assay; the effects were less severe than those with p,p'-DDE (100 mg/kg/day). When 4 mg/kg/day of TP was injected, decrease of organ weights due to benomyl was attenuated but still observed. Thus, its influence in some tissues was more potent than that of p,p'-DDE. Benomyl had no apparent effects on serum androgen levels. Microarray analysis of the gene expression profile in the ventral prostate of TP-injected castrated rats treated with benomyl indicated clear differences from the patterns observed with p,p'-DDE and flutamide. Taken together, these findings suggest the decreased organ weights observed in vivo to be caused by mechanisms that are not steroid-receptor-mediated, such as interfering with assembly of microtubules by benomyl. The study furthermore suggests that functional genomics may provide a reliable evidence for accurate categorization of test chemicals.     

Reduction of myocardial infarct size by SM-198110, a novel Na<Superscript>+</Superscript>/H<Superscript>+</Superscript> exchange inhibitor,in rabbits

The effects of 3-[2-({[amino(imino)methyl]amino}carbonyl)-4-chloro-1H-indol-1-yl]-1-propanesulphonic acid monohydrate (SM-198110), a novel potent Na⁺/H⁺ exchange inhibitor, and cariporide (Hoe642), another Na⁺/H⁺ exchange inhibitor, were studied in a myocardial ischaemia and reperfusion injury model. Anaesthetized rabbits were subjected to occlusion of the coronary artery for 30 min followed by reperfusion for 5 h. SM-198110 or cariporide was administered before ischaemia and before reperfusion. We also assessed the anti-necrotic effect of SM-198110 when given before reperfusion, both alone and together with glibenclamide, a K_ATP channel blocker, 5-hydroxydecanoate (5-HD), a mitochondrial K_ATP channel-selective blocker and 8-(p-sulphophenyl)-theophylline (8-SPT), an adenosine receptor blocker. The infarct size was reduced dose-dependently by i.v. administration of SM-198110 before ischaemia, with a significant reduction in serum creatine phosphokinase activity. Infarct sizes, normalized to the size of the area-at-risk (means±SE) were: vehicle 56.6±3.7%; low-dose SM-198110 39.2±6.3%; mid-dose 32.8±7.4% (P<0.05); high-dose 22.1±6.7% (P<0.01). This anti-necrotic effect of SM-198110 was achieved without significant haemodynamic changes. Cariporide given before ischaemia also reduced infarct size significantly and dose-dependently. SM-198110 administered before reperfusion also resulted in a dose-dependent reduction in the infarct size. Infarct sizes were: vehicle 56.6±3.7%; low-dose SM-198110 44.5±5.7%; mid-dose 36.3±6.6% (P<0.01); high-dose 34.7±3.8% (P<0.01). In contrast, cariporide given before reperfusion did not reduce infarct sizes significantly. The anti-necrotic effect of SM-198110 was observed even when given 10 min after the beginning of reperfusion. Glibenclamide and 5-HD abolished the anti-necrotic effect of treatment before reperfusion with SM-198110. However, the co-administration of 8-SPT with SM-198110 did not affect infarct size. These results suggest that, in addition to Na⁺/H⁺ exchange inhibition, mitochondrial and/or sarcolemmal K_ATP channels contribute to the anti-necrotic effect of SM-198110 when the latter is given before reperfusion.     

Characterization of human cytochrome P450 enzymes involved in the in vitro metabolism of perospirone

In vitro studies were carried out to identify the major contribution of CYP2C8, CYP2D6 and CYP3A4 to the metabolism of perospirone (cis-N-[4-[4-(1,2-benzisothiazol-3-yl)-1-piperazinyl]butyl]cyclohexane-1,2-dicarboximide monohydrochloride dehydrate), a novel antipsychotic agent, using human liver microsomes and expressed P450 isoforms. Quinidine (a specific inhibitor of CYP2D6) did not markedly affect the metabolism of perospirone, whereas quercetin (an inhibitor of CYP2C8) and ketoconazole (an inhibitor of CYP3A4) caused a decrease in the metabolism with human liver microsomes in a concentration dependent fashion. With 10 microM quercetin, the metabolism of perospirone was inhibited by 60.0% and with 1 microM ketoconazole almost complete inhibition was apparent. Anti-CYP2C8 and anti-CYP2D6 antisera did not exert marked effects, whereas anti-CYP3A4 antiserum caused almost complete inhibition. With expressed P450s, K(m) and V(max) values were 1.09 microM and 1.93 pmol/min/pmol P450 for CYP2C8, 1.38 microM and 5.73 pmol/min/pmol P450 for CYP2D6, and 0.245 microM and 61.3 pmol/min/pmol P450 for CYP3A4, respectively. These results indicated that the metabolism of perospirone in human liver was mainly catalysed by CYP3A4, and to a lesser extent CYP2C8 and CYP2D6 were responsible because kinetic data (K(m) and V(max)) of CYP2C8 and CYP2D6 suggested catalytic potential.     

Amylomyces rouxii strain CBS 438.76 affects cholesterol metabolism in cholesterol-fed rats

We examined the effects of Amylomyces rouxii, which is a mold found in some fermented foods in Indonesia, on serum cholesterol and hepatic LDL receptor mRNA in rats. Rats were fed a 0.5% cholesterol-enriched diet with (A. rouxii group) or without (control group) 30 g/kg A. rouxii for 4 wk. There were no significant differences in the body weight, food intake or liver weight among the groups. However, the weight of the cecum in the A. rouxii-fed group was significantly higher than that in the control group. The cecal pH in the A. rouxii-fed group was significantly lower than that in the control group. Cecal acetic acid, propionic acid and total SCFA concentrations in the A. rouxii-fed group were significantly higher than those in the control group. The serum total cholesterol and VLDL+intermediate density lipoprotein (IDL)+LDL-cholesterol concentrations in the control group were significantly higher than those in the A. rouxii-fed group at the end of the 4-wk feeding period. There were no significant differences in the HDL-cholesterol or triglyceride concentrations between the groups. The hepatic LDL receptor and cholesterol 7alpha-hydroxylase mRNA levels in the A. rouxii-fed group were significantly higher than those in the control group. The results of this study demonstrate that feeding of A. rouxii lowers the serum total cholesterol level by enhancement of the cecal SCFA concentration and the hepatic LDL receptor mRNA.     

Resistance of germinal nucleus to aging in Paramecium: Evidence obtained by micronuclear transplantation

A diversity of time when increase in mortality after conjugation occurs during the lifespan was found in subclones of three stocks of Paramecium caudatum. A possible micronuclear contribution to the increase in sterility has been investigated by micro-nuclear transplantation. We found two classes of micronuclei in aged clones: those that can function normally if the cytoplasmic environment is young, and those that cannot, even in a young cytoplasmic environment. The results indicate that in the former, the age-dependent increase in sterility is due to a deleterious macronucleus and/or cytoplasm, and in the latter it is due to micronuclear damage. The micronuclear damage in aged clones is probably induced by a deleterious cytoplasmic environment because aged clones with transplanted young micronuclei showed an abrupt decrease in progeny survival between 14 and 42 cell divisions after transplantation. Overall, the micronucleus seems not to be a source of age-related damage but rather is subjected to damage from macronuclear and/or cytoplasmic sources.     

Adenoid cystic carcinoma of maxillary sinus with metastatic hepatocellular carcinoma. Case report

A case of collision tumor in the left maxillary sinus composed of adenoid cystic carcinoma (ACC) and metastatic hepatocellular carcinoma (HCC) is reported. Radiographic examination revealed masses in the liver and bilateral lung metastases. Histologically, proliferation of tumor cells with resemblance to HCC was observed, in addition to the ACC. For this reason, differential diagnosis between a second primary tumor and metastasis was made. The metastatic lesion immunohistochemically showed positivity for hepatocyte antigen (OCH1E5) and protein induced by vitamin K absence or antagonist II (PIVKA-II), sustaining the HCC diagnosis. Primary ACC and metastatic HCC in the maxillary sinus are rare, and this may therefore be the first case of maxillary sinus tumor with both these elements.     

A Case of Graft Infection 10 Years After Ascending Aorta Replacement

A 52-year-old man was admitted with anemia and slight fever, which he had for the last 2 months. He had undergone replacement of the ascending aorta for acute aortic dissection 10 years previously. Echocardiography demonstrated a flailing thin structure in the anterior wall of the ascending aorta corresponding to the proximal portion of the prosthetic graft. This abnormal echocardiographic finding led us to repeat blood cultivation. We finally detected Enterococcus facium and Staphilococcus epidermidis in his blood sample. We diagnosed this as a graft infection and prepared for surgical re-replacement of the infected graft. While he was waiting for the operation, an infectious aneurysm of a tibialis posterior artery ruptured and an emergency operation was done. Replacement of the infected ascending aorta graft was done thereafter. In surgery, 2-cm-long vegetation was found. It stuck to the graft wall near the former hole used for air removal in the first surgery. The patient recovered fully and left our hospital after 3 months of postoperative antibiotics therapy. This rare case of aortic graft infection long after the original replacement surgery suggests the importance of thorough echocardiographic investigation of prosthetic graft infection as a possible cause of fever of unknown origin.     

The dynamic state of the concentrations of copper and histidine, and the complex effects of histidine and copper on the formation of lipid peroxidation in sera of undernourished young women

OBJECTIVES: First, we observed that copper and histidine levels were increased in the sera of undernourished women. The objective of this study was to clarify the reason for the increase in copper and histidine. Furthermore, we tried to determine the compound(s) to which the increased copper was binding, and examined the effect of the increased copper and histidine on lipid peroxidation. METHODS: We investigated young women's diets and took blood samples, and the contents of histidine in the sera were determined by HPLC. The contents of copper were determined by flameless atomic absorption spectroscopy. The subjects were classified into three groups according to the concentration of histidine in the sera. The contents of copper and lipid peroxide in the sera were compared among the high histidine group and the other groups. We also examined the ability of the complexes to prevent LDL oxidation induced by copper, using an in vitro assay. RESULTS: The contents of lipid peroxide were lower in the high histidine group than in the other groups. Furthermore, the complexes of histidine and copper inhibited the formation of peroxidized lipids in an in vitro assay. CONCLUSIONS: These results indicate that histidine masks copper, reducing oxidation reaction. They also suggest that the complexes are suited for plasma antioxidation, preventing oxidative modification of lipids in the sera of undernourished women. The increased histidine appeared to be an effective trap for active oxygen.