Concise review: Cancer cell reprogramming and therapeutic implications

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The cancer stem cell (CSC) act as tumor initiating cells.

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Reprogramming technology can convert cells into CSCs.

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Metabolic reprogramming is critical for CSCs.

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MiRNA can mediate cancer cell reprogramming as emerging alternatives.

The cancer stem cell (CSC) hypothesis postulates that cancer originates from the malignant transformation of stem cells and is considered to apply to a variety of cancers. Additionally, cancer cells alter metabolic processes to sustain their characteristic uncontrolled growth and proliferation. Further, microRNAs (miRNAs) are found to be involved in acquisition of stem cell-like properties, regulation and reprogramming of cancer cells during cancer progression through its post-transcriptional-regulatory activity. In this concise review, we aim to integrate the current knowledge and recent advances to elucidate the mechanisms involved in the regulation of cell reprogramming and highlights the potential therapeutic implications for the future.

Evaluation of a receptor gene responsible for maternal blood IgY transfer into egg yolks using bursectomized IgY-depleted chickens

In avian species, maternal immunoglobulin Y (IgY) is transferred from the blood to the yolks of maturing oocytes; however, the mechanism underlying this transfer is unknown. To gain insight into the mechanisms of maternal IgY transfer into egg yolks, IgY-depleted chickens were generated by removing the bursa of Fabricius (bursectomy) during egg incubation, and their egg production and IgY transport ability into egg yolks were determined. After hatching, blood IgY concentrations of the bursectomized chickens decreased gradually until sexual maturity, whereas those of IgA remained low from an early stage of growth (from at least 2 wk of age). Chickens identified as depleted in IgY through screening of blood IgY and IgA concentrations were raised to sexual maturity. At 20 wk of age, both blood and egg yolk IgY concentrations in the IgY-depleted group were 600-fold lower than those of the control group, whereas egg production did not differ between the groups. Intravenously injected, digoxigenin-labeled IgY uptake into the egg yolk was approximately 2-fold higher in the IgY-depleted chickens than in the controls, suggesting that IgY depletion may enhance IgY uptake in maturing oocytes. DNA microarray analysis of the germinal disc, including the oocyte nucleus, revealed that the expression levels of 73 genes were upregulated more than 1.5-fold in the IgY-depleted group, although we could not identify a convincing candidate gene for the IgY receptor. In conclusion, we successfully raised IgY-depleted chickens presenting a marked reduction in egg yolk IgY. The enhanced uptake of injected IgY into the egg yolks of the IgY-depleted chickens supports the existence of a selective IgY transport mechanism in maturing oocytes and ovarian follicles in avian species.

The Effect of Metadherin on NF-κB Activation and Downstream Genes in Ovarian Cancer

Ovarian cancer (OC) is the most aggressive gynecological cancer. Even with the advances in detection and therapeutics, it still remains clinically challenging and there is a pressing need to identify novel therapeutic strategies. In searching for rational molecular targets, we identified metadherin (MTDH), a multifunctional gene associated with several tumor types but previously unrecognized in OC. In this study, we found the MTDH is overexpressed in OC tissues. Through in vitro assays with overexpression cells, we characterized the role of MTDH. We confirmed MTDH stable overexpression significantly increased the expression of TNF-α, IL-6, IL-8, IL-10, and IL-1β. Interestingly, NF-kappa-B (NF-κB) and MTDH were found in a feed-forward loop motif. Thus, our findings support the notion that the MTDH and NF-κB signaling network contributes to OC traits. MTDH represents a new OC-associated gene that can contribute to insights of OC biology and suggests other treatment strategies.

Circumpapillary structure-function relationships with microperimetry and spectral domain optical coherence tomography in glaucoma: a pilot study

Purpose

To compare the relationships between circumpapillary microperimetry (MP)-sensitivity measurements and various circumpapillary retinal thickness parameters in healthy and primary open-angle glaucoma (POAG) eyes.

Methods

In 14 eyes of 14 healthy subjects and 22 early–moderate POAG eyes of 22 patients, circumpapillary optical coherence tomography thickness measurements (RS-3000 Advance OCT, NIDEK) of the retinal nerve fiber layer (cpRNFL), total retina (cpTR), and ganglion cell complex (cpGCC) and outer retina (cpOR) and circumpapillary MP-sensitivity measurements (MP-3 microperimeter, NIDEK) were made in 12 sectors of identical circumpapillary circles. The structure-function relationship was investigated in each sector.

Results

Statistically significant correlations with circumpapillary MP-sensitivity values were found for cpRNFL in five sectors, cpTR in nine sectors, cpGCC in nine sectors, and cpOR in three sectors. The structure-function relationship was strong (r=0.4–0.69) in three sectors for cpRNFL, in six for cpTR, in four for cpGCC, and in one for cpOR. The relationship was very strong (r>0.7) in one sector for cpRNFL, cpTR, and cpGCC, and in no sectors for cpOR. The very strong relationships all occurred in sector 5 (inferotemporal sector).

Conclusion

In our pilot study, the circumpapillary structure-function relationship was more extensive for cpTR thickness and cpGCC thickness than for cpRNFL thickness, which suggests that the former parameters may require greater attention in structure-function research into glaucoma.

Ingestion of paddy rice increases intestinal mucin secretion and goblet cell number and prevents dextran sodium sulfate-induced intestinal barrier defect in chickens

Paddy rice is a potential feed grain for chickens, whose strong gizzards can crush the hull. Here, we investigated whether paddy rice rich in hull-derived water-insoluble dietary fiber stimulates intestinal mucin secretion and production, as well as the possible involvement of paddy rice in intestinal barrier function. Layer male chicks at 7 d of age were divided into four groups according to the diet: corn, polished rice, brown rice, or paddy rice (650 g/kg diet), which they ate for 14 consecutive days. At 21 d of age, the birds were refed their experimental diets, and small intestinal mucin fractions were collected to determine intestinal mucin content. Small intestinal mucin secretion was induced most strongly in the paddy rice group (Experiment 1). The rank order of diet-induced mucin secretion was paddy rice > corn = brown rice > polished rice. Ileal MUC2 gene expression and ileal number of goblet cells were highest in the paddy rice group (Experiment 1). A study of bromodeoxy-U uptake into ileal epithelial cells indicated the increase in goblet cells in the paddy rice group was related to accelerate epithelial cell migration (Experiment 2). A single supplementation of isolated rice hulls without kernels increased MUC2 gene expression and goblet cell numbers (Experiment 3), suggesting the importance of the hull's bulk-forming capacity on mucin production. Finally, chicks fed corn or paddy rice were orally administered dextran sodium sulfate (DSS) to disrupt intestinal barrier function. In the DSS-treated birds, the intestinal permeability of fluorescein isothiocyanate dextran in the everted gut sacs was much lower in the paddy rice group than in the corn group (Experiment 4), showing that paddy rice protects against mucosal disruption. In conclusion, ingestion of paddy rice increases intestinal mucin secretion and production through enhanced MUC2 gene expression and epithelial turnover and prevents DSS-induced intestinal barrier defects in chickens.

Expression of platelet-derived growth factor and its receptors in spontaneous canine hemangiosarcoma and cutaneous hemangioma

Hemangiosarcoma (HSA) is a malignant neoplasia of vascular endothelial cells (ECs). Our previous report on the expression of vascular endothelial growth factor, basic fibroblast growth factor, and their receptors in canine HSA suggested an autocrine/ paracrine mechanism of tumor growth. However, the influence of other angiogenic growth factors in canine HSA was not elucidated; therefore, the expression of platelet-derived growth factor (PDGF) and its receptors was investigated by immunohistochemical analysis. Forty-six canine HSAs and 21 canine cutaneous hemangiomas (HAs) were analyzed. For immunohistochemistry, anti-PDGF-BB, anti-PDGFR-α, and anti-PDGFR-β antibodies were utilized as primary antibodies. Immunoreactivities were scored as strongly positive (>25% positive neoplastic cells), weakly positive (1-25% positive neoplastic cells), and negative if not staining at all. In cutaneous HA, 33.3% and 57.1% of cases were strongly and weakly positive, respectively, and 43.5% and 13.0% of HSAs were strongly and weakly positive for PDGF-BB, respectively. Moreover, 38.1% and 28.6% of cutaneous HAs cases were strongly and weakly positive, respectively, and 23.9% and 4.3% of HSAs cases were strongly and weakly positive, respectively, for PDGFR-α. Thirty-five HSAs cases (76.1%) were strongly positive, and the remaining 11 (23.9%) were weakly positive for PDGFR-β. In contrast, 18 (72.0%) cutaneous HAs were negative, and only 3 cases (12.0%) were weakly positive, for PDGFR-β. The proportion of strongly positive cases of HSAs was significantly higher than that of cutaneous HA for PDGFR-β (P<0.01), while PDGFR-α was highly expressed in cutaneous HA and may be related to pathogenesis of cutaneous HA. Therefore, PDGFR-β may be associated with the malignant nature of canine HSA.

Immunohistochemical analysis of the Akt/mTOR/4E-BP1 signalling pathway in canine haemangiomas and haemangiosarcomas

The specific signalling pathways that are deregulated in canine endothelial tumours have not yet fully elucidated. Therefore, the aim of the present study was to examine activation of the Akt/mammalian target of rapamycin (mTOR)/eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) signalling pathway in spontaneously arising canine haemangiomas (HAs) and haemangiosarcomas (HSAs) in order to identify novel molecular targets for treatment. Surgically-resected samples of HA (n = 27), HSA (n = 37), granulation tissue (n = 4) and normal skin (n = 4) were investigated by immunohistochemistry. Approximately 80% of the HSA samples had moderate to intense expression of phosphorylated Akt at Ser473 (p-Akt Ser473), p-Akt Thr308, p-4E-BP1 Thr37/46 and eukaryotic initiation factor 4E, which was significantly higher than in the HAs and was similar to the expression in activated endothelial cells (ECs). Although p-mTOR complex1 (p-mTORC1) Ser2448 was expressed by most of the activated ECs, only 35% of the HSA samples had weak to moderate expression. Because mTORC2 and phosphorylates Akt Ser473 was activated in HSA samples, the present findings suggest that the mTORC2/Akt/4E-BP1 pathway, regulated independently of mTORC1, may be important for targeting therapy in canine HSAs.

Higher incorporation of heterologous chicken immunoglobulin Y compared with homologous quail immunoglobulin Y into egg yolks of Japanese quail (Coturnix japonica)

In avian species, blood IgY is selectively incorporated into the yolks of maturing oocytes, although the precise mechanism is poorly understood. Our previous study showed that 22% of i.v.-injected heterologous chicken IgY (cIgY) was incorporated into egg yolks of Japanese quail (Coturnix japonica). However, it is not known whether homologous quail IgY (qIgY) can be more efficiently incorporated into quail egg yolks than cIgY. Therefore, we compared the uptakes of qIgY and cIgY i.v. administered into quail egg yolks and further characterized the uptakes of these 2 antibodies into quail ovarian follicles. Quail IgY and cIgY purified from the blood of the respective bird were labeled with digoxigenin, and their uptakes into quail egg yolks were determined by ELISA. Unexpectedly, total incorporation of the injected qIgY was only one-third of that of cIgY, although much more qIgY was left in blood compared with cIgY, suggesting that qIgY is the less preferable antibody as a transport ligand into quail egg yolks. On the other hand, deposition of the qIgY into heart, lung, liver, spleen, kidney, and ovarian follicular membrane was markedly higher than that of cIgY. Amino acid sequence analysis of 3 peptides derived from the trypsin-digested qIgY heavy chain revealed low homology between qIgY and cIgY. In conclusion, our results show that heterologous cIgY is more efficiently incorporated into quail egg yolks than homologous qIgY, possibly due to a distinctive antibody transport system existing in oocytes. The present results also may provide a new strategy for delivering useful proteinaceous substances into egg yolks in an attempt to produce designer eggs.

Teratoma of the umbilical cord in a giraffe (Giraffa camelopardalis reticulata)

A 12-year-old pregnant female giraffe (Giraffa camelopardalis reticulata) died approximately 2 months prior to her anticipated parturition date. At necropsy, a mass measuring approximately 20 x 36 x 20 cm was observed, attached to the umbilical cord, the latter being otherwise normal in appearance. Histologically, the mass contained 3 germinal tissue components with areas of squamous epithelium, respiratory epithelium, primitive neural tissues, glial tissue, peripheral nerve, adipose tissue, cartilage, and smooth muscle. Based on these findings, the tumor was diagnosed as a teratoma originating from the umbilical cord. This is possibly the second reported case of umbilical cord teratoma in animals.

An Aneurinibacillus sp. strain AM-1 produces a proline-specific aminopeptidase useful for collagen degradation

AIMS

We have been for a species of thermophilic bacteria that can effectively decompose collagen and collagen peptides that tend to be hard-to-degrade proteins because of their high content of proline residues. This study focused upon the enzymatic degradation of prolyl peptides by thermophilic bacteria.

METHODS AND RESULTS

A strain, AM-1, producing a proline-specific aminopeptidase was isolated using a medium containing gelatin that was taken from soil samples collected at Arima Hot Spring located near Kobe, Japan. The strain showed the strongest level of hydrolysing activity toward prolyl-p-nitroanilide, and the activity proved to be thermostable. Phylogenetic analysis based on 16S rDNA sequences revealed that the isolated strain AM-1 was closest to Aneurinibacillus thermoaerophilus DSM10154T in its characteristics. Analysis of the purified proline-specific aminopeptidase suggested that the enzyme is an aminopeptidase containing metal that includes important disulphide bond(s). The strain AM-1 aminopeptidase has more similarities with leucyl aminopeptidases, but its activity level differs greatly with prolyl peptides.

CONCLUSIONS

The proline-specific aminopeptidase from strain AM-1 is the first from the genus Aneurinibacillus and may be a new type of aminopeptidase for hydrolysing prolyl peptide. This enzyme also contributed to the degradation of collagen when used in combination with another collagenolytic protease.

SIGNIFICANCE AND IMPACT OF THE STUDY

The proline-specific aminopeptidase obtained from strain AM-1 may be used in the treatment of wastewater containing collagen that is encountered in the meat industries, and for decreasing bitter peptides in milk products.

Improvement of growth and nutritive value in chicks with non-genetically modified phytase product from Aspergillus niger

1. Non-genetically modified (non-GM) phytase product derived from Aspergillus niger possesses various side active enzymes including alpha-amylase, protease, cellulase and hemicellulase. In contrast, the product of genetically modified (GM) phytase product has much less side active enzyme since the capacity of phytase production is reinforced by gene modification. In the present study we have tried to determine whether the difference of side enzyme activity of phytase product affects growth performances and nutritive value in chicks; in addition we tried to characterise the physiological change induced by the difference of side active enzymes. 2. Single Comb White Leghorn male chicks at 7 d of age were fed on experimental barley-based diets for 10 d. The feeding trial was of a factorial design (3 x 2 x 2), having three types of dietary phytase products (control, non-GM or GM phytase products derived from A. niger at 1000 U/kg diet), two levels of dietary available P supplement (0 or 6 g/kg diet) and two levels of dietary protein (CP 180 or 120 g/kg). 3. The non-GM phytase product caused a 6% increase in final body weight and feed efficiency compared with the control and the GM phytase product without interacting with dietary protein and available P level. However, in birds given available P-free diet, both non-GM and GM phytase products induced a 20% increase in plasma P concentration, suggesting no difference in phytase activity between the non-GM and GM phytase products. 4. The balance study showed that the metabolisable energy of the non-GM phytase product (15.6 +/- 0.05 kJ/g diet) was significantly higher among the treatments (control, 15.1 +/- 0.05; GM phytase product 15.3 +/- 0.07). The non-GM phytase product also increased the rate of food passage through the crop, and caused a drastic reduction in intestinal weight, perhaps as a consequence of digestion of non-starch polysaccharides. 5. We conclude that the side active enzymes in non-GM phytase product improve growth performance and nutritive value of the diet in chicks. However, the efficacy of phytase activity should not be different between non-GM and GM phytase products.

[Coronary artery bypass grafting in the patients with renal dysfunction]

We studied coronary artery bypass grafting (CABG) in patients with renal dysfunction. From April 1994 to October 1999, 59 patients with renal dysfunction underwent CABG. The patients were divided into 2 groups: group A: 18 patients with end stage renal disease who were receiving hemodialysis, group B; 41 patients with creatinine levels higher than 1.5 mg/dl who were not supported by dialysis. We compared and analyzed the findings of there 2 groups. Regarding preoperative factors, the incidence of old myocardial infarctions, diabetes mellitus and old cerebral infarctions did not differ significantly between the 2 groups. Regarding perioperative factors, the incidence of the number of vessel diseases, emergency operations, operation times and blood transfusions did not differ significantly between the 2 groups. Regarding the post-operative course, the hospital mortality rates demonstrated low levels in 2 groups. The graft patency of group A was 95%, while it was 99% in group B. The post-operative in-hospital days was 24.8 days in the group A, while it was 30.1 days in the group B. No significant difference was observed between the 2 groups. As a results, post-operative hemodialysis was needed in 8 of the patients who underwent on-pump CABG from group A. The actual survival rates were 75.3% in group A and 84.3% in group B at 4 years. The cardiac event free rate for group A was 93.3%, while it was 97.5% in group B at 4 years. In conclusion, CABG may improve the post-operative outcome in renal dysfunction patients. In addition, the use of off-pump CABG is also considered to achieve a better renal function than on-pump CABG.

The vaso-contractile action of zooxanthellatoxin-B from a marine dinoflagellate is mediated via Ca2+ influx in the rabbit aorta

We previously showed that zooxanthellatoxin-B, isolated from dinoflagellate, caused a sustained contraction of the aorta in an external Ca2+-dependent manner. To clarify the role of Ca2+ in this action, we examined the effects of zooxanthellatoxin-B as well as a depolarizing stimulus (60 mM KCl), using the simultaneous recording for cytosolic Ca2+ level (fura-2) and developed tension in the rabbit aorta. KCl (60 mM) elicited a rapid cytosolic Ca2+ elevation followed by a pronounced contraction, and time required for half-maximum contraction was 2 min. Zooxanthellatoxin-B caused an increase in cytosolic Ca2+ followed by a gradual contraction, with a time for half-maximum contraction of 5-10 min in a concentration-dependent manner. We found a strong correlation between Ca2+ elevation and the contraction in zooxanthellatoxin-B action. In a Ca2+-free solution, zooxanthellatoxin-B caused neither the contraction nor the increase in cytosolic Ca2+. Furthermore, both pre- and post-treatment with verapamil, a voltage-operated Ca2+-channel blocker, partially suppressed both an increase in cytosolic Ca2+ and the contraction by zooxanthellatoxin-B. Zooxanthellatoxin-B-induced contraction was also inhibited by other voltage-operated Ca2+-channel blockers: nifedipine or diltiazem. These results suggest that zooxanthellatoxin-B-elicited contraction is caused by a Ca2+ influx into the smooth muscle cells, partially via voltage-operated Ca2+ channels.

Insulin administration suppresses an increase in insulin-like growth factor binding protein-2 gene expression stimulated by fasting in the chicken

1. We examined the changes in plasma IGF-I concentration and tissue IGFBP-2 gene expression of young fasted chickens refed a commercial diet or administered bovine insulin intravenously. 2. Plasma IGF-I concentration was decreased by fasting for 2 d. Although plasma IGF-I concentration was increased by refeeding, it didn't recover to the level of chickens fed a commercial diet ad libitum. 3. Insulin administration lowered plasma IGF-I concentration compared to other groups. 4. Hepatic IGFBP-2 mRNA was increased by fasting for 2 d and decreased by refeeding for 6 h. Insulin administration also decreased hepatic IGFBP-2 gene expression stimulated by fasting to the level of refed chickens. 5. IGFBP-2 mRNA in the gizzard was increased by fasting for 2 d and tended to decrease after refeeding for 6 h. Insulin administration decreased gizzard IGFBP-2 gene expression to less than that in refed chickens. 6. There was no between-treatment difference in IGFBP-2 mRNA in the brain and kidney. 7. These results suggest that the changes in IGFBP-2 gene expression in the liver and gizzard by fasting and refeeding might be partly regulated by the alteration in plasma insulin concentration.

Off-pump CABG for a patient with a brain tumor

Coronary artery bypass grafting (CABG) without cardiopulmonary bypass (off-pump CABG) was performed on a patient with a brain tumor. A patient with effort angina of the left anterior descending artery (LAD), and diagonal branch stenosis was referred to us for CABG. He had a mass lesion in the brain that was diagnosed as meningioma involving the internal carotid artery and a middle cerebral artery. To avoid brain complications, we performed off-pump CABG using the internal thoracic and radial arteries to the LAD and a diagonal branch. Off-pump CABG was an effective method to avoid brain complications for patients with a brain tumor involving cerebral vessels.

Factors regulating amylase secretion from chicken pancreatic acini in vitro

In mammals, cholecystokinin regulates pancreatic exocrine secretion under physiological conditions. We have shown, however, that cholecystokinin at physiological concentrations does not induce pancreatic amylase secretion in birds. Therefore, we investigated the effects of various neurotransmitters and gut hormones on the pancreatic amylase secretory response in isolated chicken pancreatic acini. Acetylcholine (half-maximal stimulation at 800 nM) and vasoactive intestinal polypeptide (half-maximal stimulation at 40 pM) produced a concentration-dependent increase in amylase secretion at physiological concentrations. The combination of acetylcholine and vasoactive intestinal polypeptide produced an additive response in amylase secretion. Sodium nitroprusside, a spontaneous nitric oxide releaser, and bombesin, induced amylase secretion at concentrations greater than 10 nM and 100 nM, respectively. Gastrin and secretin increased amylase secretion at pharmacological concentrations (10 to 100 nM). Our findings suggest that neural regulation is important for pancreatic enzyme secretion in birds and the contribution of gut hormones seems to be physiologically unimportant.

Control of c-fos expression in STC-1 cells by peptidomimetic stimuli

Enteroendocrine cells respond to nutrient and non-nutrient stimuli in the gut lumen. The intestinal hormone cholecystokinin (CCK) is secreted in response to luminal fatty acids, amino acids, peptides and proteins. The peptidomimetic cephalosporins have been reported to provide model, stable, compounds with similar secretagogue activity to peptide. Putative luminal stimuli also influence transcriptional activity in enteroendocrine cells, but the mechanisms are uncertain. In the present study we have investigated the control of c-fos expression in STC-1 cells (an enteroendocrine cell line). Peptidomimetics stimulated calcium-dependent release of CCK, and increased intracellular calcium, phosphorylation of p42/44 mitogen-activated protein kinase (MAP kinase) and c-fos mRNA abundance. Hypotonic stress also increased p42/44 MAP kinase phosphorylation and c-fos mRNA, but not CCK release. The increase in c-fos mRNA was strikingly potentiated by peptidomimetics in hypotonic medium. Increased c-fos expression, but not CCK release, was suppressed by the MAP kinase (MEK) inhibitor PD98059, and by the tyrosine kinase inhibitor genistein. We conclude that in STC-1 cells, peptidomimetics act through the p42/44 MAP kinase pathway to increase c-fos expression but not exocytosis. Moreover, a putative non-nutritive stimulus, hypotonic stress, may interact with this pathway to enhance c-fos expression, independently of hormone release.

Synthesis and biological evaluation of analogs of the marine toxin polycavernoside A

Second generation analogs of polycavemoside A (2) possessing a side chain at C-15 different from that of the natural toxin have been synthesized. The in vivo toxicities of these new compounds (expressed as the minimal lethal dose) have been evaluated in mice (ip) and compared to 2, its aglycone (8), and polycavemoside B (9). The bioactivity profile of enynene 5 is particularly notable.

Inverted T graft: novel technique using composite radial and internal thoracic arteries

BACKGROUND

Multiple arterial revascularization is feasible because of the excellent long-term patency of the arterial grafts compared with venous grafts. We present a new operative technique for multiple arterial revascularization using composite radial and internal thoracic arterial grafts.

METHODS

Between January and September 1997, 12 patients had coronary artery bypass grafting with inverted T graft. The indications for inverted T graft were aortic calcification in 4 patients, repeat coronary artery bypass grafting in 1 patient, and total arterial revascularization in 7 young patients. The inverted T graft was constructed by interconnecting the coronary arteries and radial artery with end-to-side and side-to-side anastomoses, and by anastomosing the internal thoracic artery to the side of radial artery.

RESULTS

Overall, 38 distal anastomoses (average number per patient, 3.2) were made with an inverted T graft. There were no deaths or perioperative myocardial infarctions. Postoperative angiography disclosed that all of the anastomoses were patent.

CONCLUSION

This technique allows multiple arterial revascularizations without technical difficulty. It is useful in patients with aortic calcification, repeat coronary artery bypass grafting patients, and young patients who are candidates for total arterial revascularization.

Thrombomodulin levels in patients with coronary artery disease

We investigated the association between the serum level of thrombomodulin and known coronary risk factors in 119 men who underwent coronary angiography. Total cholesterol level was significantly higher in patients with coronary atherosclerosis than in those without. Significantly higher frequency of hypertension was noted in patients with coronary atherosclerosis. Uric acid level and frequency of smoking tended to be higher in patients with coronary atherosclerosis but the differences were short short of the significant level. The serum level of thrombomodulin between patients with coronary atherosclerosis and those without was not statistically significant. Age, blood urea nitrogen, and creatinine were positively correlated and creatinine clearance was inversely correlated with the serum level of thrombomodulin. Serum levels of total cholesterol, triglyceride, high-density lipoprotein cholesterol, uric acid, and fasting blood sugar, plasma level of fibrinogen, and body mass index were not related to the serum level of thrombomodulin. There was no significant correlation between the severity of coronary atherosclerosis, hypertension, alcohol use, or smoking and the serum level of thrombomodulin. Restenosis was present in 8 of 16 patients who underwent percutaneous transluminal coronary angioplasty and had a follow-up angiogram at 6.0 +/- 3.0 months. Univariate analysis revealed no significant difference in the thrombomodulin level with and without restenosis. The present findings suggest that elevated thrombomodulin levels in patients with coronary artery disease may reflect retention of thrombomodulin due to decrease in thrombomodulin clearance in the kidney.

Vasoconstriction induced by zooxanthellatoxin-B, a polyoxygenated long-chain product from a marine alga

We found that zooxanthellatoxin-B from a symbiotic marine alga, Symbiodinium sp., caused a concentration-dependent contraction of the rabbit isolated aorta at concentrations of 10(-7)-10(-5) M. Verapamil (10(-6) M) and mefenamic acid (10(-5) M) significantly attenuated the contractile response to zooxanthellatoxin-B at lower concentrations (10(-7)-10(-6) M) but not at higher concentrations (3 X 10(-6)-10(-5) M). The response to zooxanthellatoxin-B was partly inhibited by phentolamine (10(-6) M), whereas it was potentiated by ouabain (10(-5) M). Tetrodotoxin (10(-6) M), methysergide (10(-6) M), chlorpheniramine (10(-6) M) or indomethacin (3 X 10(-6) M), however, did not affect it. The zooxanthellatoxin-B-induced contraction was abolished by incubation in Ca2+-free solution. The contractile response increased in a concentration-dependent fashion with Ca2+ (0.03 and 10 mM) or Sr2 + (0.10 and 10 mM). After treatment with verapamil (10(-6) or 5 X 10(-6) M), the concentration-contractile response curves for Ca2+ and Sr2+ in the presence of zooxanthellatoxin-B were shifted to the right in parallel. MgCl2 (10 mM) shifted the concentration-response curve for Ca2+ more markedly than did verapamil. Zooxanthellatoxin-B increased tissue Na+ and reduced tissue K+ contents in the aorta, suggesting that zooxanthellatoxin-B increases Na+ and K+ permeability across the plasma membrane. These results suggest that the zooxanthellatoxin-B-induced contraction of the aorta is caused mainly by a direct action on smooth muscle, i.e., an increase in Ca2+ permeability that occurs at least partly through voltage-sensitive Ca2+ channels as well as through nonselective cation channels in the cell membrane of smooth muscle.

Evaluation of five imidazopyrazinone-type chemiluminescent superoxide probes and their application to the measurement of superoxide anion generated by Listeria monocytogenes

Superoxide-triggered chemiluminescence of five new imidazopyrazinone derivatives was investigated using the hypoxanthine-xanthine oxidase system as the source of superoxide anion. The results showed that they are highly sensitive and have favorable properties in measuring superoxide anion. With those new probes, the generation of superoxide anion from the bacteria Listeria monocytogenes was examined. The results confirmed the previous report that L. monocytogenes is an unusual organism that extracellularly and continuously generates a high level of superoxide anion in the presence of acetaldehyde. The data indicated that two of the probes, 3,7-dihydro-2-methyl-6-phenylethynylimidazo[1,2-a]pyrazin-3- one (4) and its methoxy derivative (5), are highly sensitive and useful in the measurements of superoxide anion and are clearly superior to 3,7-dihydro-2-methyl-6-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-3-on e (MCLA), which-has been generally considered the most sensitive superoxide probe in the past. When tested at a probe concentration of 3.3 microM, the luminescence response and the signal-background ratio of compound 4 were 1.5 and 2.5 times those of MCLA, respectively, and the signal-background ratio of compound 5 was almost 15 times that of MCLA, though the luminescence response of this compound was slightly lower than that of MCLA. The low probe concentration used enhances the usefulness of probes in the measurements of superoxide in functioning biological systems.

Involvement of phospholipase C-gamma2 in activation of mitogen-activated protein kinase and phospholipase A2 by zooxanthellatoxin-A in rabbit platelets

Zooxanthellatoxin-A (ZT-A), a polyhydroxypolyene isolated from a symbiotic dinoflagellate Symbiodinium sp., caused thromboxane A2-(TXA2) dependent and genistein-sensitive aggregation in rabbit platelets. Our study was performed to clarify the mechanism of the action of ZT-A. ZT-A caused an increase in tyrosine phosphorylation of 42-kDa protein, which is defined as p42 mitogen-activated protein kinase (MAPK) by immunoprecipitation. Although indomethacin (10 microM) completely inhibited ZT-A-induced TXB2 release, it partially inhibited the MAPK activation. The remained MAPK activation was completely inhibited by genistein (50 microM). Genistein (50 microM), by itself, abolished TXB2 release induced by ZT-A. ZT-A (2 microM) stimulated liberation of arachidonic acid and the subsequent metabolites such as TXB2 and 12-hydroperoxyeicosatetraenoic acid. However, ZT-A-stimulated phosphoinositide hydrolysis which was due to an increase in tyrosine phosphorylation of phospholipase C-(PLC)gamma2. The phosphorylation of PLC-gamma2 and the phosphoinositide hydrolysis were also partially inhibited by indomethacin (10 microM), and were abolished by a combined treatment of indomethacin (10 microM) and genistein (50 microM). ZT-A- (2 microM) induced MAPK activation in the presence of indomethacin (10 microM) was concentration-dependently inhibited by staurosporine and calphostin C, protein kinase C inhibitors. PD98059 (50 microM), a MAPK kinase inhibitor, also inhibited ZT-A-induced TXB2 release. Depletion of external Ca++ abolished ZT-A- (2 microM) induced MAPK activation, phosphoinositide hydrolysis, arachidonic acid liberation and TXB2 release. These results suggest that ZT-A stimulates a protein tyrosine kinase in the presence of external Ca++, resulting in the activation of MAPK probably via PLC-gamma2 and protein kinase C. The MAPK stimulated a liberation of arachidonic acid that is rapidly converted to TXA2. The released TXA2 causes aggregation accompanied with second stimulation of MAPK cascade.

Tyrphostin 23 blocks phosphorylation of p42 but not p38 mitogen-activated protein kinase by zooxanthellatoxin-A

Zooxanthellatoxin-A isolated from a symbiotic dinoflagellate, caused aggregation in rabbit platelets that was inhibited by genistein (50 microM) and tyrphostin 23 (500 microM). Zooxanthellatoxin-A increased tyrosine phosphorylation of 42-kDa proteins which were identified as p42 and p38 mitogen-activated protein kinase (MAPK) by immunoprecipitation. Tyrphostin 23 inhibited the tyrosine phosphorylation of p42 MAPK but not p38 MAPK. In contrast, genistein abolished zooxanthellatoxin-A-induced tyrosine phosphorylation of both p42 and p38 MAPK. The results suggest that tyrphostin 23 selectively inhibits tyrosine phosphorylation of p42 MAPK. The p38 MAPK tyrosine phosphorylation is not involved in zooxanthellatoxin-A-induced platelet aggregation.

[A study about the mechanism of hepatocyte injury induced by endotoxin--interaction of Kupffer cells and polymorphonuclear neutrophils (PMNs)]

Focusing our attention on the TNF (tumor necrosis factor) produced by Kupffer cells (KCs). The role of KCs and polymorphonuclear neutrophils (PMNs) in endotoxin (LPS)-induced hepatocellular injury was investigated. This study used the culture fluid supernatant of KCs which had been stimulated with LPS as the "LPS stimulation supernatant", and evaluated hepatocellular injury as ornithine carbamyl transferase percent leakage. There was no difference between groups I (HCs: hepatocytes) and II (HCs + PMNs), but there were differences between groups I and III (HCs + LPS stimulation supernatant, groups II and IV (HCs + LPS stimulation supernatant + PMNs), and III and IV. There was no significant difference between III and V (III + anti-TNF antibody), but a difference was found between IV and VI (IV + anti-TNF antibody). These findings suggest that PMNs activated by KCs-generated TNF as well as KCs-derived humoral factors other than TNF play a role in the development of LPS-induced hepatocellular injury.

Prostaglandin E2 derivative, enprostil, reduces hepatic triacylglycerol content in Japanese quail

This study investigated the effect of prostaglandin E2 derivative, enprostil, on the hepatic lipid metabolism of Japanese quail. In experiment 1, the birds received 0.1, 1, 10 or 100 micrograms enprostil/kg body weight intraperitoneally, and they were killed after 10, 30, 60 and 120 min. After 60 min, hepatic triacylglycerol content was reduced most effectively by 10 micrograms enprostil/kg body weight. In experiment 2, effect of enprostil (10 micrograms/kg body weight) on liver enzyme activities associated with lipid metabolism and plasma lipid concentrations was examined. There were no significant differences in malic enzyme and carnitine palmitoyltransferase activities. Peroxisomal beta-oxidation in birds which received enprostil was significantly lower than that in birds receiving the vehicle. Enprostil caused a significant decrease in plasma triacylglycerol and non-esterified fatty acid concentration. We conclude that the administration of enprostil reduces hepatic triacylglycerol content through the decreased influx of non-esterified fatty acid.

Aspirin promotes hepatic triacylglycerol accumulation in essential fatty acid-deficient Japanese quail

This study was conducted to investigate whether the effect of a high dose of aspirin on hepatic triacylglycerol content is altered by dietary essential fatty acids (EFA) in Japanese quail. The birds were given an EFA-free or EFA-adequate [containing 2% (w/w) linoleic acid] diet ad libitum from 7 to 24 days of age. On the final experimental day, the birds received vehicle or 800 mg aspirin/kg body weight intraperitoneally and were killed 4 h subsequently. In birds fed the EFA-free diet, hepatic triacylglycerol content was more than 2 times higher after aspirin compared with vehicle treatment; in contrast, aspirin had no affect in birds fed the EFA-adequate diet. Liver malic enzyme and phosphatidate phosphohydrolase activities, which are related to lipid synthesis, were not affected by dietary EFA or aspirin treatment. Liver carnitine palmitoyltransferase activity in the birds fed the EFA-free diet was significantly lower than that in the birds fed the EFA-adequate diet, but aspirin did not affect this activity. In groups given the EFA-free diet, peroxisomal beta-oxidation was increased by the aspirin treatment. We conclude that acute administration of aspirin to Japanese quail on an EFA-free diet induces hepatic triacylglycerol accumulation, and that changes in lipid synthesis and degradation do not contribute to this phenomenon.

Involvement of (n-6) essential fatty acids and prostaglandins in liver lipid accumulation in Japanese quail

OBJECTIVE

To investigate the involvement of (n-6) essential fatty acids, such as linoleic acid [18:2(n-6)] or gamma-linolenic acid [18:3(n-6)], and of prostaglandins on liver lipid accumulation in Japanese quail.

DESIGN

Effects of graded amounts of aspirin, which inhibits prostaglandin synthesis, on liver weight were determined in experiment 1. Experiment 2 was designed to clarify the effect of dietary essential fatty acid sources and inhibition of prostaglandin synthesis on the liver fat and fatty acid profile.

ANIMALS

Female Japanese quail.

PROCEDURE

In experiment 1, from 1 to 3 weeks of age, birds were fed ad libitum the essential fatty acids-free or linoleic acid-adequate (2%) diets with graded amounts of aspirin (0, 0.1, 0.2, and 0.4%). In experiment 2, from 1 to 4 weeks of age, birds were fed the same amount of essential fatty acids-free, linoleic acid-adequate, or gamma-linolenic acid (0.4%) diets with (0.2%) or without aspirin.

RESULTS

In experiment 1, in groups given the essential fatty acids-free diet, liver weight increased with an increase in dietary aspirin concentration. In experiment 2, gamma-linolenic acid completely prevented liver triacylglycerol and cholesterol accumulation induced by the essential fatty acids-free diet. Aspirin treatment significantly lowered plasma prostaglandin F2 alpha concentration, but did not affect liver lipid concentrations. In groups fed the essential fatty acids-free diets, however, aspirin treatment increased liver weight and liver triacylglycerol concentration by 20 and 40%, respectively.

CONCLUSIONS

gamma-Linolenic acid or its metabolites, but not linoleic acid itself, are important factors in reducing fatty liver in Japanese quail with the essential fatty acids-deficient condition.

Role of dietary gamma-linolenic acid in liver lipid metabolism in Japanese quail

1. The importance of linoleic acid (18:2n-6) itself and of dietary gamma-linolenic acid (18:3n-6) as essential fatty acids (EFA) in Japanese quail were investigated with regard to liver lipid metabolism. Experimental diets were made by adding of 0, 2 or 4 g gamma-linolenic acid/kg, or 20 g linoleic acid/kg to an n-6 EFA-free diet. From 3 to 6 weeks of age, birds were fed equal amounts of experimental diets. 2. Liver weight and lipid content in birds fed the 2 and 4 g gamma-linolenic acid/kg diet were significantly lower than those in birds fed the gamma-linolenic acid-free diet. However, no significant difference was observed between the gamma-linolenic acid- and linoleic acid-supplemented diets. 3. In birds fed the 4 g gamma-linolenic acid/kg diet, the proportion of arachidonic acid in the liver lipid was similar to that in quail fed the 20 g linoleic acid/kg diet, implying a conversion rate from linoleic acid to gamma-linolenic acid of approximately 20% of whole body content. 4. It is concluded that linoleic acid itself is not essential for Japanese quail and that at least 2 g/kg of gamma-linolenic acid in the diet completely prevents liver enlargement accompanied by lipid accumulation.

The sugar composition and partial structure of the self-induced endogenous elicitor from potato

The self-induced endogenous elicitor isolated from potato having molecular weight 9200 was degraded with trifluoroacetic acid to determine the sugar composition. The requisite composition of the elicitor was estimated to be a 2:3:4:7 mixture of galactose, rhamnose, arabinose, and galacturonic acid. Furthermore, the structure of oligogalacturonic acid moiety was found to consist mainly of alpha-1,4-pentagalacturonic acid by use of high pH anion exchange chromatography-pulsed amperometric detection.