Review: Exploration of placentation from human beings to ocean-living species.

This review covers four topics. 1) Placental pathology in Himalayan mountain people. To determine morphological changes of the placenta at high altitude, pathological examination was made of 1000 Himalayan placentas obtained in Nepal and Tibet and the results compared with Japanese placentas delivered at sea level. Characteristic findings in the placental villi of the Himalayan group included high incidences of villous chorangiosis and chorangioma. These processes were clarified by ultrastructural observation. 2) Placentation in Sirenians. The giant Takikawa sea cow, which lived 5 million years ago, was discovered on Hokkaido, Japan. It was an ancestor of the dugong as well as the manatees. Sirenia, the sea cow group, shares a common ancestor with Proboscidea, the elephants, even though they now inhabit quite different environments. A comparison was made of their zonary endothelial type of placentation. 3) Placentation in sharks and rays. The remarkable placentation of hammerhead sharks and manta rays is described. 4) Placentation in the Antarctic minke whale. Placental tissue samples of this whale were obtained from the Japan Institute of Cetacean Research. In an ultrastructural study of the utero-placental junction, microfilamental processes of the allantochorionic zone and crypt formation were visualized.

Effects of oral administration of ciclosporin A on skin carcinogenesis: a study using the two-stage carcinogenesis protocol in mice.

BACKGROUND: Development of malignant skin neoplasms in patients receiving cyclosporin A (CsA) has been reported. The relationship between the pathogenesis of skin carcinogenesis and the dose of CsA is still unclear. AIM: To clarify the effect of oral administration of CsA, especially its dose, on skin carcinogenesis. METHODS: Hr-1 hairless mice were assigned to the following four groups: (i) control group (n = 8), given vehicle intragastrically six times/week and acetone applied to the skin of the back; (ii) chemical-alone (n = 11), given vehicle intragastrically + application of 7,12-dimethylbenz[a]anthracene (DMBA) once week and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) twice week to the back; (iii) CsA-alone group (n = 8), given CsA intragastrically (10 mg/kg) six times/week and vehicle applied to the back twice week; and (iv) CsA + chemical group (n = 8), given 10 mg/kg CsA intragastrically + topical DMBA and TPA. The number of papules > 3 mm in diameter that had developed on the back after 15 weeks was counted. The mean epidermal thickness and number of dermal infiltrates were determined. The same experiments were performed using CsA at doses of 5 and 20 mg/kg. RESULTS: Oral administration of either 10 or 20 mg/kg CsA significantly enhanced the formation of papillomas by DMBA and TPA, but no enhancement was observed when 5 mg/kg CsA was administered. The mean epidermal thickness and number of dermal infiltrates were significantly greater in the CsA + chemical group than in the chemical-alone group. CONCLUSION: These data suggest that oral administration of CsA in excess of a certain dose can accelerate tumour development in mice.

Self-reversal phenomena of toroidal current by reversing the external toroidal field in helicity-driven toroidal plasmas.

In order to understand self-organization in helicity-driven systems, we have investigated the dynamics of low-aspect-ratio toroidal plasmas by decreasing the external toroidal field and reversing its sign in time. Consequently, we have discovered that the helicity-driven toroidal plasma relaxes towards the flipped state. Surprisingly, it has been observed that not only toroidal flux but also poloidal flux reverses sign spontaneously during the relaxation process. The self-reversal of the magnetic fields is attributed to the nonlinear growth of the n=1 kink instability of the central open flux.

Cytochrome P450 enzymes involved in the metabolic pathway of the histamine 2 (H2)-receptor antagonist roxatidine acetate by human liver microsomes.

Roxatidine acetate hydrochloride (ROX, 2-acetoxy-N-[3-[m-(1-piperidinylmethyl)phenoxy]propyl]acetamide hydrochloride, CAS 78273-80-0), a histamine 2 (H2)-receptor antagonist, has been clinically applied for the treatment of gastritis, gastric and duodenal ulcers. There is no report on the identification of the metabolic enzyme of M-1 (2-hydroxy-N-[3-[m-(1-piperidinylmethyl)phenoxy]propyl]acetamide), the pharmacologically active metabolite, in humans. In this study, the Cytochrome P450 (CYP or P450) enzymes which participate in the metabolism of ROX were identified using human liver microsomes and S9 fractions. M-1 was converted to M-4 (3-[m-(1-piperidinyl-methyl)phenoxy]propylamine) by the enzyme reaction with the S9 but not with microsomes. M-4 was further metabolized to M-5 (3-[m-(1-piperidinylmethyl)phenoxy]propanol) by microsomes. The metabolism was inhibited by coumarin and anti-CYP2A1 serum. (3-[m-(1-piperidinylmethyl)-phenoxy]propionic acid) and M-3 (m-(1-piperidinylmethyl) phenol) formation from M-5 were inhibited by quinidine and anti-CYP2D6 serum. Moreover, M-5 was converted to M-2 and M-3 by cDNA-expressed CYP2D6. In conclusion, this study shows that microsomal enzymes do not participate in the clearance of the active metabolite M-1, CYP2A6 primarily catalyzes M-5 formation from M-4, and CYP2D6 primarily catalyzes M-2 and M-3 formation from M-5 in humans.

Effect of ultraviolet A on ornithine decarboxylase and metallothionein gene expression in mouse skin.

BACKGROUND: Ultraviolet A (UVA) is known to induce the expression of many stress responsive genes due to the generation of reactive oxygen species (ROS). However, UVA's role in inducing metallothionein (MT) gene expression has not been studied. Furthermore, our group demonstrated that UVA enhanced 12-O-tetradecanoylphorbol-13-acetate (TPA)-mediated induction of ornithine decarboxylase (ODC) activity in mouse skin (1). METHODS: We examined the interaction of UVA, TPA and antioxidants on the induction of MT and ODC mRNA in mouse skin. Female CD-1 mice were exposed to UVA (19 J/cm2) and total RNA was isolated from the skin. Northern blot analysis for MT and ODC mRNAs was performed. ODC activity in mouse epidermis was also determined in some experiments. RESULTS: UVA induced MT mRNA in mouse skin; however, it did not increase ODC mRNA. 1,4-Diazabicylo-[2,2,2]-octane (DABCO), a singlet oxygen scavenger, reduced UVA-mediated induction of MT mRNA by 40%. The data suggest that ROS produced by UVA exposure may contribute to its ability to induce MT mRNA. UVA slightly enhanced TPA-mediated ODC mRNA induction, while it enhanced ODC enzyme activity 70%. UVA additively intensified TPA-mediated MT mRNA induction. alpha-Tocopherol pretreatment inhibited the induction of ODC enzyme activity by TPA treatment combined with UVA exposure (TPA + UVA); however, alpha-tocopherol had less of an inhibitory effect on ODC mRNA induction by TPA + UVA. Curcumin, a plant pigment, dramatically inhibited both TPA- and TPA + UVA-induced expression of ODC and MT genes. CONCLUSIONS: These results demonstrate that UVA can induce MT gene expression and enhance TPA-induced ODC and MT gene expression. The data further suggest that these effects are partially mediated by ROS.

Mitochondrial encephalomyopathy with lactic acidosis and stroke like episodes (MELAS) with prominent degeneration of the intestinal wall and cactus-like cerebellar pathology.

A 67-year-old woman had frequent subacute ileus, hearing difficulty, muscle atrophy and stroke-like episodes. Computed tomography revealed multiple low-density areas, which did not correlate with the vascular supply, in the cerebral cortex. She had metabolic disturbance comprising lactic acidosis and elevated pyruvate level. Her skeletal muscle biopsy specimen showed ragged-red fibers, and mitochondrial DNA analysis revealed a point mutation at position 3243, findings consistent with MELAS. Examination of her small intestine revealed a necrotic zone and numerous abnormal large mitochondria in the smooth muscle cells, vascular media and endothelium, and intestinal ganglion cells. The cerebral cortex showed multiple microcystic necrotic foci in cerebral cortex. Cactus-like pathology resembling the changes associated with Menkes' kinky hair disease and torpedoes were observed in the cerebellar Purkinje cells. The intestinal dysmotility due to MELAS and cerebellar changes were presumed to be associated with a disturbance of copper metabolism.

Adhesion molecule detection in a case of early cerebral malaria: immunohistochemical and electron microscopic findings.

A case of early cerebral malaria caused by Plasmodium falciparum was studied. P-selectin glycoprotein ligand 1 (PL1) was detected along the inner surface of the infected red blood cells (IRBCs), which ordinarily are not positive for PL1 immunohistochemically, suggesting PL1 being the product of parasite. The electron microscopic finding showed granular deposits in the corresponding lesion, consistent with PL1 deposition, in the IRBCs firmly attached to the endothelium of small cerebral vessels. Most of the IRBCs were round shaped as though they lost their capacity to change shape. The therapeutic strategy was expected against adhesion molecules such as PL1 and for maintaining or restoring the metamorphic capacity of IRBCs.

Identification of Gaucher cells in the chorionic villi associated with recurrent hydrops fetalis.

Recurrent non-immune hydrops fetalis has rarely been reported. In order to detect the risk of recurrence in a subsequent pregnancy, one should carefully consider the possibility of an inborn error of metabolism. In such cases, placental examination may be useful in detecting such metabolic storage disorders in the fetus, which usually present as vacuolization of placental cells. We describe a rare case of recurrent hydrops that was detected by placental examination. Through light microscopy, electron microscope (EM) studies and beta-glucocerebrosidase activity the disease was identified as Gaucher's disease.

Establishment and characterization of a human rectal neuroendocrine carcinoma xenograft into nude mice.

BACKGROUND: Carcinoid tumor has been recognized as having a much wider spectrum than was previously thought. Now the term 'neuroendocrine carcinoma' (NEC) has been suggested to describe malignant epithelial tumors of neuroendocrine differentiation. Its biological behavior has not been well characterized because of the lack of in vivo models. MATERIALS AND METHODS: A metastatic inguinal lymph node from rectal NEC was used for heterotransplantation into nude mice. Histochemical and immunohistochemical stainings were performed in addition to ultrastructural investigations. Hormonal peptides were measured in both xenograft tumor tissue and serum. RESULTS: We succeeded in heterotransplantation of human rectal NEC into nude mice. To date tumorigenicity has been retained for approximately 38 months. The xenograft tumor was a histopathologically identical tumor. The immunohistochemical expression of the various hormonal peptides in the xenograft was essentially the same as that of the primary rectal tumor. Tissue and serum hormonal peptides in the xenografted tumor were measured. Serum glucagon and serotonin were significantly higher than in control mice. CONCLUSIONS: The expression of various hormonal peptides in NEC may vary depending on the surrounding environment. The establishment of NEC in xenografts provides a model for further study of the biological behavior of NEC, as well as the in vivo effects of chemotherapeutic agents on tumor growth and the release of hormonal peptides.

Inhibitory effect of oleanolic acid on 12-O-tetradecanoylphorbol-13-acetate-induced gene expression in mouse skin.

Oleanolic acid (OA) has been shown to inhibit mouse skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA). This study was designed to examine the effect of OA on the TPA-induced expression of the ornithine decarboxylase (ODC) gene as well as other genes. OA inhibited the induction of ODC activity and mRNA level produced by TPA in the skin of female CD-1 mice. Preapplication of OA (10 mumol) to the mouse dorsal skin produced an approximately 50% decrease in TPA (8 nmol)-induced epidermal ODC activity, as well as ODC gene expression. These results suggest that OA inhibits TPA-induced ODC mainly at the transcriptional level. In addition to ODC, TPA also stimulated metallothionein (MT) gene expression in mouse skin. A dose of 2.5 mumol of OA diminished the TPA-induced MT mRNA 50%. Treatment with OA (10 mumol) after TPA (8 nmol) application also inhibited ODC and MT gene expression which suggests that OA does not compete with TPA for its receptor. OA pretreatment also prevented c-fos gene expression. All of these findings suggest that OA diminishes some signal transduction pathways of TPA to suppress target gene expression in mouse skin. This study suggests that OA might be a general inhibitor against TPA-stimulated gene expression in mouse skin.

The expression of heme oxygenase-1 gene responded to oxidative stress produced by phorone, a glutathione depletor, in the rat liver; the relevance to activation of c-jun n-terminal kinase.

Phorone, a glutathione (GSH) depletor, induces the expression of mRNAs of heme oxygenase-1 (HO-1) and c-jun by mediating the activation of activated protein-1 (AP-1) in rat livers. We have shown that phorone activates c-Jun N-terminal kinase (JNK), thus leading to c-Jun phosphorylation, and transactivation of AP-1 and HO-1 gene expression in the rat liver in response to oxidative stress. The in-gel kinase assay showed that phorone activated JNK1 predominantly in the rat liver nuclear extract. The JNK activation by phorone was slightly observed at 1 hr after administration and gradually increased with time. Ser73-phosphorylation of c-Jun catalyzed by JNK was significantly altered by changing hepatic GSH levels based on the results observed by the combined injection of buthionine sulfoximine (BSO) or GSH isopropyl ester (GIP) with phorone. Namely, BSO, an inhibitor of GSH biosynthesis, enhanced phorone-mediated c-Jun phosphorylation as well as AP-1 binding activity. However, GSH isopropyl ester prevented GSH depletion and abolished both c-Jun phosphorylation and the activation of AP-1 binding evoked by phorone. GSH isopropyl ester also suppressed phorone-produced HO-1 and c-jun gene expressions to 25 and 30% of the induced level. Perfluorodecanoic acid (PFDA) reduced GSH S-transferase activity, prevented phorone-mediated GSH depletion and abolished either HO-1 or c-jun mRNA induction by phorone. These results indicated that oxidative stress under GSH depletion produced by phorone could activate preferentially JNK and lead to the transcriptional activation of AP-1 and consequently to HO-1 gene expression. This study suggests that JNK activation could be one of the major signaling pathways to transmit intracellular events to the nuclei during oxidative stress via GSH depletion by phorone in rat livers.

Induction of hepatic heme oxygenase and changes in cytochrome P-450s in response to oxidative stress produced by stilbenes and stilbene oxides in rats.

Both trans- and cis-stilbene oxide (TSO and CSO) markedly induced heme oxygenase-1 (HO-1) at the transcriptional level in rat liver. HO-1 induction by TSO and CSO was preceded by glutathione (GSH) depletion in the liver. Pretreatment of rats with buthionine sulfoximine (BSO), an inhibitor of GSH biosynthesis, enhanced GSH depletion evoked by either TSO or CSO and augmented the increase in HO-1 mRNA. In contrast, pretreatment with perfluorodecanoic acid (PFDA), which reduced hepatic GSH S-transferase activity, prevented TSO- and CSO-mediated GSH depletion and abolished HO-1 induction. In addition, TSO and CSO enhanced c-jun but not c-fos mRNA, which is in parallel with the HO-1 mRNA change. These findings indicate that the oxidative stress evoked by GSH depletion after the treatment of rats with stilbene oxides could stimulate both HO-1 and c-jun gene expression. Pretreatment with either BSO or PFDA also affected the induction of CYP2B1/2 mRNA and apoprotein by TSO or CSO, suggesting that not only the change of heme pool size but also some other unknown factor or factors may be involved in the regulation of the CYP2B1/2 and HO-1 gene expression. cis-Stilbene (CS), a parent compound of CSO, also induced HO-1 mRNA, together with hepatic GSH depletion, but trans-stilbene (TS) failed to elevate HO-1 mRNA under the experimental conditions. In addition, CS increased CYP2B1/2 mRNA, whereas TS did not. These results suggest that CS could be rapidly oxidized by cytochrome P-450 (P-450) to CSO, leading to GSH depletion in the liver. Such differences in the hepatic metabolic pathways of CS and TS are attributable to the differential effects on HO and P-450 induction by these compounds. Like other phenobarbital-type P-450 inducers, TSO and CSO also induced CYP2C6 and 3A2 apoproteins in rat liver. Stilbene oxide reduced CYP2E1 mRNA and apoproteins for CYP2E1 and 2C11. All of these findings indicate that stilbene compounds have unique effects on hepatic HO-1 and P-450 regulation in rats.

Cooperative induction of c-fos and heme oxygenase gene products under oxidative stress in human fibroblastic cells.

Heme oxygenase-1 is a stress responsive enzyme and implicated in a protective function of cellular damage. We investigated cellular events leading to the heme oxygenase-1 gene expression induced by sublethal concentrations of glutathione depletors, phorone and diethyl maleate, in human fibroblastic cells. Accumulation of heme oxygenase-1 mRNA by glutathione depletors was canceled by simultaneous treatment with cycloheximide, an inhibitor of protein synthesis; however, the inhibitory effect decreased when the inhibitor was added 30 min later. Among the inducible early response genes, the c-fos expression was significantly elevated with a peak at 30 min after the agents. Accumulation of heme oxygenase-1 and c-fos transcripts was abrogated in cells pretreated with 1,4-diazabicyclo[2.2.2]octane, an oxygen-free radical quencher. Decrease in glutathione levels preferentially activated extracellular-signal regulated kinases rather than other stress-activated protein kinases such as c-Jun N-terminal kinases and p38 MAP kinase. Pretreatment of cells with PD 98059, an inhibitor of the extracellular-signal regulated kinase cascade, or the c-fos antisense oligodeoxynucleotide inhibited the heme oxygenase-1 induction elicited by glutathione depletion. These observations indicated that c-Fos protein plays a role in heme oxygenase-1 gene expression induced by glutathione depletion-mediated oxidative stress in human fibroblasts.

Suppressed expression of phenobarbital-inducible hepatic cytochrome P-450s in Eisai-hyperbilirubinuria rats (EHBR/Eis).

The differential induction of hepatic cytochrome P-450 (P450) was studied in Eisai-hyperbilirubinuria rats (EHBR/Eis). This rat is a mutant that has as high a concentration of bilirubin in the urine as in the plasma. A single administration of trans-stilbene oxide (TSO, 2 mmol/kg), a phenobarbital (PB)-type P450 inducer, did not increase total P450, the CYP2B1/2 or the CYP2C6 in EHBR/Eis liver. TSO was able to induce delta-aminolevulinic acid synthetase and heme oxygenase, rate-limiting enzymes in heme biosynthesis and degradation, respectively, in both EHBR/Eis and Sprague-Dawley rat (SDR), the strain from which EHBR/Eis is derived. TSO also produced similar effects on glutathione depletion and on the activities of other drug-metabolizing enzymes in both strains. A 23-fold increase in CYP2B1/2 mRNA in the SDR liver was observed 24 hr after TSO treatment. In the EHBR/Eis strain, however, TSO increased CYP2B1/2 mRNA only 2-fold. In addition, repeated injection of TSO failed to induce P450 isozymes, CYP2B1/2, CYP2C6 or CYP3A2 in EHBR/Eis. On the other hand, there was essentially no difference in the induced levels of CYP1A1/2 apoprotein and mRNA between twins of SDR and EHBR/Eis livers treated with 3-methylcholanthrene or 1-benzylimidazole. The increased levels of both CYP2B1/2 apoprotein and mRNA from EHBR/Eis liver treated with TSO and 1-benzylimidazole were much smaller (2.5- and 5-fold increases, respectively) than from the SDR liver (17.5- and 15-fold increases, respectively). Although PB expressed CYP2B1/2 apoprotein and mRNA to a similar extent in both homozygous and heterozygous EHBR/Eis livers, CYP3A2 and CYP2C6 were less responsive to PB in homozygous EHBR/Eis. Repeated treatment with TSO induced these isozymes in heterozygote but not in homozygote. These findings suggest that the suppressed expression of PB-inducible P450 isozyme genes in the EHBR/Eis liver may be a general phenomenon associated with PB-type inducers. Therefore, EHBR/Eis may be experimentally useful for studying the mechanism of P450 induction by PB and PB-type inducers.

Heme oxygenase-1 gene expression by a glutathione depletor, phorone, mediated through AP-1 activation in rats.

This study shows that induction of heme oxygenase-1 (HO-1) gene expression by a glutathione (GSH) depletor, phorone, is inhibited by cycloheximide pretreatment and involves changes in c-jun, not c-fos, mRNA. Buthionine sulfoximine (BSO) enhanced markedly both c-jun and HO-1 gene expression evoked by phorone. Phorone dramatically increased AP-1 binding activity, which was blocked by unlabeled AP-1 oligonucleotide and abolished by anit-Jun antibodies, but not anti-Fos antibodies. In addition, pretreatment with dexamethasone, an inhibitor of AP-1 DNA binding, inhibited phorone-mediated HO-1 mRNA induction. These findings suggest that HO-1 induction by phorone is likely to involve in the activation of AP-1 (Jun/Jun) binding, which could be associating with GSH depletion.

Metallothionein synthesis induced by interferon alpha/beta in mice of various zinc status.

We studied the ability of interferon alpha/beta (IFN) to induce metallothionein (MT) synthesis in mice. Male mice were injected intraperitoneally with mouse IFN (5 x 10(5) IU/mouse). Plasma Zn levels were reduced at 4 hr after injection, reached a minimum value at 6 hr, and then returned to the control level at 8 hr. Hepatic MT concentrations began to increase at 4 hr and reached maximum values at 6 hr. Induction of MT gene expression and protein synthesis was confirmed by Northern blot analysis and radioimmunoassay, respectively. The induction of MT synthesis in the liver by IFN was dose-dependent. The data suggest that induction of MT-mRNA and the protein in the liver by IFN occurs rapidly but is rather transient. Furthermore, MT synthesis was not induced by IFN in the liver of mice given a Zn-deficient diet, whereas IFN induced increases in the activity of 2',5'-oligoadenylate synthetase in the spleen were unaffected by Zn status. Thus, induction of hepatic MT synthesis by IFN is influenced by Zn status.

Molybdate impairs glycosaminoglycan sulfation in rat cartilage.

The mechanism by which molybdate produces joint and bone deformities is not known. However, we recently reported that molybdate decreases the sulfation of acetaminophen in rat liver. Therefore, the purpose of the present study was to determine the effect of molybdate on the sulfation of glycosaminoglycans (GAGS) and whether manganese-induced joint and bone deformities might be due to this mechanism. Molybdate (15 mmol/kg, po) did not alter total GAG content in patella and articular cartilage of rats assayed 24 hr after administration. Nevertheless, [35S]sulfate uptake into both patella and articular cartilage was decreased dramatically (70 and 50%, respectively) by molybdate. Molybdate did not affect GAG chain elongation, as there was no effect of molybdate on [3H]glucosamine uptake into patella cartilage. These results indicate that molybdate impairs sulfation of GAGs. In an attempt to determine the mechanism of the molybdate-induced decrease in GAG sulfation, the effect of molybdate and sulfate on the incorporation of sulfate into GAGs was examined in vitro using monolayer chondrocyte cultures. Molybdate reduced the sulfation of GAGs in chondrocytes in vitro, but only at concentrations higher than the blood concentration of molybdate given in vivo that decreased GAG sulfation. Molybdate given in vivo decreases plasma sulfate to levels, which when used in vitro, decreases GAG sulfation. Therefore, molybdate treatment decreases sulfate availability and the sulfation of glycosaminoglycans.

Enhancing effect of ultraviolet A on ornithine decarboxylase induction and dermatitis evoked by 12-o-tetradecanoylphorbol-13-acetate and its inhibition by curcumin in mouse skin.

BACKGROUND: Previous studies have demonstrated appreciable tumor induction in mouse skin by daily irradiation with high-power long-wavelength ultraviolet A (UVA). OBJECT: The aim of the present study was to examine the enhancing effects of UVA on changes in mouse skin mediated by the tumor promoter 12-o-tetradecanoylphorbol-13-acetate (TPA) by measurement of ornithine decarboxylase (ODC) activity and morphometric analysis. In addition, we examined the inhibitory effects of curcumin, a component of turmeric, on these changes. METHOD: ODC activity in the epidermis of CD-1 mice was determined by the method of Russell and Snyder. Epidermal and dermal thickness, and the number of dermal infiltrating inflammatory cells were quantified using a computer-assisted image analyzer. RESULTS: A combination of topical TPA application and UVA irradiation produced a greater increment of ODC activity at 4 h than TPA alone (p < 0.05). Histopathologically, TPA plus UVA tended to increase the dermal infiltrating inflammatory cells in contrast to TPA alone. Pretreatment of mice with curcumin significantly abrogated the TPA-induced changes in ODC activity and the dermal infiltrating inflammatory cells as well as the TPA plus UVA-mediated enhancement of these changes. CONCLUSION: Our data indicate that UVA irradiation (18.72 J/cm2) significantly enhances ODC induction at an early stage (4-6 h) after topical application of TPA, and aggravates the dermatitis elicited by TPA. Pretreatment with curcumin significantly inhibits these enhancing effects.