Choriocarcinoma-like tumor in a potbellied pig (Sus scrofa).

A uterine tumor, with histological and immunohistochemical features consistent with those of human choriocarcinoma, was identified in a 10-year-old unmated female pot-bellied pig (Sus scrofa). The tumor showed biphasic proliferation of cytotrophoblast-like cells and syncytiotrophoblast-like cells. Immunohistochemically, the syncytiotrophoblast-like cells were positive for human chorionic gonadotropin, and both types of cells were positive for cytokeratin and negative for vimentin, octamer-binding transcription factor 4, and α-fetoprotein. Because syncytiotrophoblasts are absent in the normal porcine placenta, the tumor was diagnosed as a choriocarcinoma-like tumor.

Combined effects of organochlorine pesticides heptachlor and hexachlorobenzene on the promotion stage of hepatocarcinogenesis in rats.

We aimed to investigate the combined effect of organochlorine pesticides heptachlor (HEP) and hexachlorobenzene (HCB) by using a medium-term rat liver bioassay. Male F344 rats were initially administered diethylnitrosamine (DEN, 200mg/kgi.p.); after a 2-week non-dosing period, they were given diets containing HEP (5 or 25ppm), HCB (70 or 350ppm), or their mixtures (5 and 70ppm or 25 and 350ppm) for 6weeks. All rats were subjected to partial hepatectomy at week 3 and killed at week 8. We observed additive or synergistic effects of HEP and HCB in groups treated with mixtures of these pesticides. Number and area of preneoplastic foci positive for glutathione S-transferase placental form (GST-P) were consistently higher in these groups than the sum of individual values in the groups treated with HEP or HCB alone. Consistent with these findings, HEP and HCB had additive or synergistic effects on cell proliferation induction within the preneoplastic foci and cytochrome P450 (CYP) 2B1 and 3A1 induction, which may lead to more efficient metabolic activation of HEP and HCB. On the basis of these findings, we conclude that HEP and HCB have additive and synergistic effects on the development of GST-P-positive foci and that higher risks are associated with a combination of residual organochlorine pesticides in foods than with individual residual organochlorine pesticides.

Asialoerythropoietin, a nonerythropoietic derivative of erythropoietin, displays broad anti-heart failure activity.

BACKGROUND: We investigated the effects of asialoerythropoietin (asialoEPO), a nonerythrogenic erythropoietin derivative, on 3 murine models of heart failure with different etiologies. METHODS AND RESULTS: Doxorubicin (15 mg/kg) induced heart failure within 2 weeks (toxic cardiomyopathy). Treatment with asialoEPO (6.9 µg/kg) for 2 weeks thereafter attenuated the associated left ventricular dysfunction and dilatation. In addition, the asialoEPO-treated heart showed less myocardial fibrosis, inflammation, and oxidative damage, and diminished atrophic cardiomyocyte degeneration, which was accompanied by restored expression of GATA-4 and sarcomeric proteins. Mice with large 6-week-old myocardial infarctions exhibited marked left ventricular dysfunction with adverse remodeling (ischemic cardiomyopathy). AsialoEPO treatment for 4 weeks significantly mitigated progression of the dysfunction and remodeling and reduced myocardial fibrosis, inflammation, and oxidative damage. Finally, 25-week-old δ-sarcoglycan-deficient mice (genetic cardiomyopathy) were treated with asialoEPO for 5 weeks. AsialoEPO mitigated the progressive cardiac remodeling and dysfunction through cardiomyocyte hypertrophy, and upregulated expression of GATA-4 and sarcomeric proteins. AsialoEPO appears to act by altering the activity of the downstream erythropoietin receptor signals extracellular signal-regulated protein kinase, Akt, signal transducer, and activator of transcription 3 and 5 in a model-specific manner. CONCLUSIONS: The findings suggest that asialoEPO exerts broad cardioprotective effects through distinct mechanisms depending on the model, which are independent of the erythrogenic action. This compound may be promising for the treatment of heart failure of various etiologies.

Induction of peroxisomal lipid metabolism in mice fed a high-fat diet.

Peroxisomes catalyze a range of essential metabolic functions, mainly related to lipid metabolism. However, their roles in obesity have yet to be clarified. The aim of this study was to investigate the correlation between obesity and peroxisomal lipid metabolism, particularly very long-chain fatty acid (VLCFA) metabolism, gene expression of peroxisomal ß-oxidation enzymes, peroxisomal ATP-binding cassette (ABC) transporter adrenoleukodystrophy (ABCD1) gene and its related gene, ABCD2, the elongation of the VLCFA (ELOVL) gene family and the transcriptional factors involved in the regulation of these genes, including peroxisome proliferator-activated receptor α (PPARα) and sterol regulatory element-binding protein. These factors were analyzed in livers from mice fed a high-fat diet (HFD) or a regular diet (RD) for 20 weeks. Furthermore, the amounts of plasma saturated and unsaturated fatty acids, including VLCFAs, were measured. A HFD induced hepatic gene expression of not only hydroxysteroid 17-ß dehydrogenase 4 (HSD17b4) and sterol carrier protein 2 (SCP2) in peroxisomal ß-oxidation enzymes but also of ELOVL1, 2, 5 and 6, which are involved in the elongation of saturated and unsaturated VLCFAs. Furthermore, ABCD2 mRNA prominently increased in the HFD mice. The transcriptional regulator of these genes, PPARα, was also up-regulated in the HFD mice. VLCFA ratios including C24:0/C22:0, C25:0/C22:0 and C26:0/C22:0 are the most significant diagnostic markers of inherited peroxisomal diseases. These ratios were found to be low in the plasma of the HFD mice compared with the RD mice. The results suggest that HFD activates hepatic peroxisomal VLCFA metabolism, and may provide useful fundamental information to explain the role of peroxisomal function in obesity and lifestyle-related diseases.

Capsaicin inhibits IFN-gamma-induced MHC class II expression by suppressing transcription of class II transactivator gene in murine peritoneal macrophages.

Major histocompatibility complex (MHC) class II molecules play crucial roles in adaptive immune response and antigen presentation. Owing to enlargement of capsaicin's availability as an anti-inflammatory agent in medical therapeutics, we investigated the new effects of capsaicin that are related to adaptive immune response in terms of MHC class II expression in murine primary cultured macrophages. Capsaicin (0.1-10microM) reduced the expression of MHC class II mRNA levels in cultured peritoneal macrophages upon treatment with interferon (IFN)-gamma (100units/ml). In agreement with this, treatment of the cells with capsaicin also inhibited MHC class II transactivator (CIITA) mRNA expression induced by IFN-gamma in a dose-dependent manner. In contrast, production of nitric oxide, which has the ability to reduce MHC class II expression, was not enhanced but rather suppressed by capsaicin treatment in IFN-gamma-stimulated macrophages. These findings suggest that capsaicin suppresses expression of MHC class II via downregulation of CIITA transcription but not through the mediation of nitric oxide production by macrophages. These new immunopharmacological roles of capsaicin in specific transcription regulation of genes involved in antigen presentation of macrophages could be useful for the treatment of adaptive immune-mediated disorders.

Extract from Calotropis procera latex activates murine macrophages.

Calotropis procera latex has long been used in traditional medicines. Extracts from C. procera latex have been reported to have various pharmacological actions, including protection from myocardial infarction, hepatoprotective action, antitumor activity, antinociceptive, and pro- and anti-inflammatory actions. To evaluate the immunomodulatory functions of the water-soluble C. procera extract (CPE), we investigated its ability to activate macrophages-effector cells in inflammatory and immune responses. Intraperitoneal injection of CPE in mice (2 mg/mouse) induced migration of macrophages to the intraperitoneal cavity, confirming the proinflammatory effects of water-soluble CPE. The direct effects of CPE on macrophages were then assessed by measuring the production of nitric oxide (NO) as an indicator for macrophage activation. Addition of CPE (1-10 microg/ml) to the culture medium of the murine monocyte/macrophage cell line RAW264.7 caused an increase in NO production in a time- and dose-dependent manner. CPE-elicited NO production was blocked by application of an inhibitor of inducible nitric oxide synthase (iNOS). Expression of iNOS mRNA was induced by treatment of cultured macrophages with CPE. Injection of CPE in mice also resulted in an increase in plasma NO level. The results suggest that CPE activates macrophages and facilitates NO production via up-regulation of iNOS gene expression.

Capsaicin pretreatment attenuates LPS-induced hypothermia through TRPV1-independent mechanisms in chicken.

It has been demonstrated that chicken TRPV1 (transient receptor potential vanilloid of subtype-1) is insensitive to capsaicin (CAP), and therefore, a chicken model is suitable to analyze the CAP-sensitive TRPV1-independent pathway. We elucidated here the possible involvement of the pathway in hypothermia induced by bacterial endotoxin (lipopolysaccharide, LPS) in chickens. Chicks were pretreated with CAP (10 mg/kg, iv) at 1, 2 and 3 days of age to desensitize them towards the CAP-sensitive pathway. An intravenous injection of LPS in 4-day-old chicks caused progressive hypothermia, ending with collapse and 78% mortality within 12 h after injection. The CAP pretreatment rescued the LPS-induced endotoxin shock and hypothermia in chicks. LPS-induced iNOS expression as well as NO production in liver and lung was suppressed by CAP pretreatment. CAP pretreatment also attenuated hypothermia due to exposure of chicks to cold ambient temperature. These findings suggest that a CAP-sensitive TRPV1-independent pathway may be involved in pathophysiological hypothermic reactions through the mediation of NO in chickens.

Involvement of a capsaicin-sensitive TRPV1-independent mechanism in lipopolysaccharide-induced fever in chickens.

It has been demonstrated that capsaicin blocks lipopolysaccharide (LPS)-induced fever in mammals. In this study, we investigated TRPV1 (transient receptor potential ion channel of vanilloid subtype-1)-independent action of capsaicin on LPS-induced fever in chickens. The chicken is a valuable model for this purpose because chicken TRPV1 has been shown to be insensitive to capsaicin and thus the effects of capsaicin can be attributed to TRPV1-independent mechanisms. Administration of capsaicin (10 mg/kg, iv) to conscious unrestrained chicks at 5 days of age caused a transient decrease in body temperature. This effect of capsaicin was not observed in chicks that had been pretreated twice with capsaicin, indicating that the capsaicin-sensitive pathway can be desensitized. LPS (2 mg/kg, ip) induced fever that lasted for about 2.5 h, but fever was not induced in chicks that had been pretreated with capsaicin for 2 days. The preventive effect of capsaicin on LPS-induced fever was not blocked by capsazepine, an antagonist for TRPV1, but the antagonist per se blocked the febrile response to LPS. These findings suggest that a capsaicin-sensitive TRPV1-independent mechanism may be involved in LPS-induced fever.

Cold-induced expression of the VEGF gene in brown adipose tissue is independent of thermogenic oxygen consumption.

To examine whether cold-induced vascular endothelial growth factor (VEGF) gene expression in brown adipose tissue involved generation of hypoxic oxygen levels by thermogenic processes, we cold-exposed wild-type mice, as well as uncoupling protein-1 (UCP1)-ablated mice in which no thermogenesis in brown adipocytes can be induced. Cold exposure stimulated VEGF expression in both wild-type and UCP1-ablated mice. Unexpectedly, the effect was 3-fold higher in UCP1-ablated animals, whereas cultured brown adipocytes from both genotypes responded identically to norepinephrine stimulation. These results demonstrate that generation of low oxygen levels does not contribute to cold-induced VEGF expression in brown adipose tissue, but the results are consistent with an adrenergic regulation of expression.

Norepinephrine but not hypoxia stimulates HIF-1alpha gene expression in brown adipocytes.

The cellular response to hypoxic stress is mainly mediated via activation of the transcription factor hypoxia-inducible factor-1alpha (HIF-1alpha). In the present study, the sympathetically controlled brown adipose tissue was used to investigate the effect of norepinephrine on HIF-1alpha gene expression. Norepinephrine increased HIF-1alpha mRNA levels in cultured brown adipocytes, whereas the hypoxia-mimic cobalt was without effect. Cold exposure of mice increased HIF-1alpha gene expression in brown adipose tissue. In UCP1-ablated mice, which are incapable of inducing thermogenic oxygen consumption in brown adipose tissue, cold exposure generated a significantly higher elevation of HIF-1alpha mRNA levels than in wild-type. These results demonstrate that cold-induced HIF-1alpha gene expression is independent of thermogenic oxygen consumption leading to hypoxia, but is consistent with a norepinephrine regulation of HIF-1alpha gene expression. Thus, by elevating HIF-1alpha gene expression, norepinephrine may mediate an increased potential to respond to hypoxia in brown adipose tissue and possibly in other tissues.

Measurement of the propelled liquid by isolated hamster ileum as a parameter to evaluate peristalsis.

We present a method to measure the volume of liquid propelled by peristaltic movements of isolated hamster ileum as a novel means to assess peristaltic activity. The oral and aboral ends of the dissected ileum were attached to cannulas fixed horizontally. The application of intraluminal pressure by raising the level of liquid in the bottle connected to the oral end evoked peristalsis and intermittent propulsion of the intraluminal liquid. The inhibition of intrinsic neurons by tetrodotoxin stopped propulsion; this indicated that the liquid propulsion was correlated with neuron-regulated peristalsis. The volume of liquid propelled by one complete peristaltic movement was significantly greater than that by incomplete peristalsis, whereas recordings of pressure changes were indistinguishable. Inhibitors of nitric oxide synthase decreased the volume of liquid propelled by peristaltic movements, suggesting a role of nitrergic neurons in peristalsis. Our data show that the method described above might be suitable for analyzing peristalsis.

A neurophysiological evidence of capsaicin-sensitive nerve components innervating interscapular brown adipose tissue.

Neurophysiological basis for the heterogeneity of the nerve components in the brown adipose tissue (BAT) was examined in this experiment. Efferent nerve signals were recorded from the central cut end of the small nerve filament dissected from the nerve fibers innervating the interscapular BAT (IBAT). By focusing on qualitative aspects of observed compound action potentials (spikes), we found two distinctive types of spikes exhibited by the intercostal nerves innervating IBAT. The spikes mainly appeared upon sympathetic stimulations (cold stimulation and glucose administration) were characterized by low amplitude with relatively short duration (small spike) and their sensitivity to the ganglion blocker, hexamethonium (C6). On the other hand, the spikes seen throughout the experiments were characterized by high amplitude with long duration (large spike) and their insensitivity to C6. Since BAT is activated by cold and feeding via sympathetic nervous system, the small spikes seemed to be exhibited by sympathetic fibers. On the other hand, appearance of the large C6-insensitive spikes was strongly attenuated in capsaicin-desensitized rats. Even though the functional link between IBAT and C6 insensitive fibers remains unanswered, our results suggest that IBAT is under control of various nerve types including capsaicin-sensitive fibers in addition to the control of sympathetic nervous system.

An electrophysiological study of excitatory purinergic neuromuscular transmission in longitudinal smooth muscle of chicken anterior mesenteric artery.

1. The object of the present study was to clarify the neurotransmitters controlling membrane responses to electrical field stimulation (EFS) in the longitudinal smooth muscle cells of the chicken anterior mesenteric artery. 2. EFS (5 pulses at 20 Hz) evoked a depolarization of amplitude 19.7+/-2.1 mV, total duration 29.6+/-3.1 s and latency 413.0+/-67.8 ms. This depolarization was tetrodotoxin (TTX)-sensitive and its amplitude was partially decreased by atropine (0.5 microM); however, its duration was shortened by further addition of prazosin (10 microM). 3. Atropine/prazosin-resistant component was blocked by the nonspecific purinergic antagonist, suramin, in a dose-dependent manner, indicating that this component is mediated by the neurotransmitter adenosine 5'-triphosphate (ATP). 4. Neither desensitization nor blocking of P2X receptor with its putative receptor agonist alpha,beta-methylene ATP (alpha,beta-MeATP, 1 microM) and its antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic (PPADS, up to 50 microM), had significant effect on the purinergic depolarization. In contrast, either desensitization or blocking of P2Y receptor with its putative agonist 2-methylthioATP (2-MeSATP, 1 microM) and its antagonist Cibacron blue F3GA (CBF3GA, 10 microM) abolished the purinergic depolarization, indicating that this response is mediated through P2Y but not P2X receptor. 5. The purinergic depolarization was inhibited by pertussis toxin (PTX, 600 ng ml(-1)). Furthermore, it was significantly inhibited by a phospholipase C (PLC) inhibitor, U-73122 (10 microM), indicating that the receptors involved in mediating the purinergic depolarization are linked to a PTX-sensitive G-protein, which is involved in a PLC-mediated signaling pathway. 6. Data of the present study suggest that the EFS-induced excitatory membrane response occurring in the longitudinal smooth muscle of the chicken anterior mesenteric artery is mainly purinergic in nature and is mediated via P2Y purinoceptors.

A comparative histological study on the distribution of striated and smooth muscles and glands in the esophagus of wild birds and mammals.

Musculature and glands of the esophagus in various wild birds and mammals were examined histologically. Cervical and thoracic esophagi of all birds used (mallard, spot-billed duck, Ural owl and Hodgson's hawk-eagle) were comprised of smooth muscle fibers only. In contrast, esophagi of the nutria, Japanese raccoon dog, common raccoon and Japanese marten consisted largely of striated muscle fibers. In the masked palm civet, Japanese macaque and bottlenose dolphin, esophageal muscle layers consisted of both striated and smooth muscle fibers. Esophageal glands were observed except for the nutria and masked palm civet. These results show a wide variety of the structural composition in the esophagus of wild animals, particularly mammals, examined in this study.