Effects of rapid or slow body weight reduction on intramuscular protein degradation pathways during equivalent weight loss on rats

The purpose of this study was to compare the effects of short-term fasting-induced rapid weight loss with those of slower but equivalent body weight loss induced by daily calorie restriction on muscle protein degradation pathways and muscle protein content. Male Fischer rats were subjected to either 30 % calorie restriction for 2 weeks to slowly decrease body weight (Slow) or 3-day fasting to rapidly decrease body weight by a comparable level of that of the Slow group (Rapid). The final body weights were about 15 % lower in both the Slow and Rapid groups than in the Con group (p<0.001). The total protein content and wet weight of fast-twitch plantaris muscle, but not slow-twitch soleus muscle, were significantly lower in the Rapid group compared with the control rats fed ad libitum. Substantial increases in the expression ratio of autophagosomal membrane proteins (LC3-II/-I ratio) and polyubiquitinated protein concentration, used as biomarkers of autophagy-lysosome and ubiquitin-proteasome activities, respectively, were observed in the plantaris muscle of the Rapid group. Moreover, the LC3-II/-I ratio and polyubiquitinated protein concentration were negatively correlated with the total protein content and wet weight of plantaris muscle. These results suggest that short-term fasting-induced rapid body weight loss activates autophagy-lysosome and ubiquitin-proteasome systems more strongly than calorie restriction-induced slower weight reduction, resulting in muscular atrophy in fast-twitch muscle.

Ecteinascidins. A review of the chemistry, biology and clinical utility of potent tetrahydroisoquinoline antitumor antibiotics

The ecteinascidin family comprises a number of biologically active compounds, containing two to three tetrahydroisoquinoline subunits. Although isolated from marine tunicates, these compounds share a common pentacyclic core with several antimicrobial compounds found in terrestrial bacteria. Among the tetrahydroisoquinoline natural products, ecteinascidin 743 (Et-743) stands out as the most potent antitumor antibiotics that it is recently approved for treatment of a number of soft tissue sarcomas. In this article, we will review the backgrounds, the mechanism of action, the biosynthesis, and the synthetic studies of Et-743. Also, the development of Et-743 as an antitumor drug is discussed.

Reducing effects of polyphenols on metmyoglobin and the in vitro regeneration of bright meat color by polyphenols in the presence of cysteine

The effect of polyphenols and related phenolic compounds on the reduction of metmyoglobin (MetMb) to oxymyoglobin (MbO2), in the presence of cysteine, was investigated. Caffeic acid, dihydrocaffeic acid, and hydroxtyrosol (600 μmol/L) did not show any reducing activity individually. However, their highly potent activity in the reduction of MetMb to MbO2 was observed in the presence of equimolar amounts of cysteine. On the basis of the analytical results for the redox reaction products generated during the MetMb-reducing reaction of caffeic acid, we proposed a mechanism for the polyphenol-mediated reduction of MetMb. As per the proposed mechanism, the antioxidant polyphenols having a catechol substructure can effectively reduce MetMb to MbO2 with chemical assistance from nucleophilic reactive thiol compounds such as cysteine. Moreover, cysteine-coupled polyphenols such as cysteinylcaffeic acids (which are coupling products of caffeic acid and cysteine) can be used as preserving agents for retaining the fresh meat color, because of their powerful reducing effect on MetMb. The reduction of MetMb to MbO2 changes the color of meat from brown to the more desirable bright red.

Identification of a potent xanthine oxidase inhibitor from oxidation of caffeic acid

Inhibitory activity of Fe-ion-catalyzed radical oxidation products from 22 types of phenolic compounds toward xanthine oxidase (XO) was investigated. Phenols are readily oxidizable compounds in nature and, thus, showed potent antioxidant activities. Among the phenols screened in this study, noticeable activity was observed in the oxidation product of caffeic acid, whereas almost no XO-inhibitory activity of caffeic acid was observed. Assay-guided purification of the oxidation product of caffeic acid afforded a highly potent XO inhibitor, with an IC50 value that was calculated to be 60 nmol L(-1), which indicated XO-inhibitory activity much stronger than that of allopurinol (IC50 = 1 μmol L(-1)), a potent XO inhibitor and excellent medicine for the treatment of gout. The chemical structure of this new XO inhibitor was investigated by one- and two-dimensional NMR and HR-ESI-MS analyses, and the unique tetracyclic structure was confirmed by synthesis starting from commercially available 1,2,4-trimethoxybenzene and 3,4-dimethoxylbenzoyl chloride.

Metmyoglobin reduction by polyphenols and mechanism of the conversion of metmyoglobin to oxymyoglobin by quercetin

The effect of antioxidant polyphenols and related phenolic compounds from plants on the reduction of metmyoglobin (MetMb) was investigated. Potent activity in the reduction of MetMb to oxymyoglobin (MbO2), a bright red protein in meat, was observed for three flavonols, kaempferol, myricetin, and quercetin, at 300 μmol/L against 60 μmol/L MetMb. Sinapic acid, catechin, nordihydroguaiaretic acid, taxifolin, morin, and ferulic acid promoted reduction at 600 μmol/L. A mechanism for the reduction by one of the active flavonols, quercetin, was proposed on the basis of analytical results for redox reaction products derived from quercetin. This suggested the importance of a high propensity toward reduction of the flavonol structure and rapid convertibility of the quinone form to the phenol form for the MbO2 reduction and the maintenance of the level of MbO2 produced.

Synergistic increase in cell lethality by dieldrin and H2O2 in rat thymocytes: effect of dieldrin on the cells exposed to oxidative stress

Dieldrin, one of persistent pesticides, is highly resistant to biotic and abiotic degradation. It is accumulated in organisms. Recent studies suggest that dieldrin exerts a potent cytotoxic action on cells exposed to oxidative stress. In this study, the effect of dieldrin on rat thymocytes exposed to hydrogen peroxide (H2O2)-induced oxidative stress was examined. Dieldrin at 5μM and H2O2 at 300μM slightly increased cell lethality from a control value of 5.4±0.5% (mean±standard deviation of four experiments) to 7.8±1.3% and 9.0±0.3%, respectively. Simultaneous application of dieldrin and H2O2 significantly increased cell lethality to 46.2±1.8%. The synergistic increase in cell lethality was dependent on dieldrin concentration (0.3-5μM) but not on H2O2 concentration (30-300μM). Dieldrin accelerated H2O2-induced cell death, which was estimated with the help of annexin V-FITC and propidium iodide. Presence of either dieldrin or H2O2 decreased the cellular content of nonprotein thiol and increased intracellular Zn(2+) concentration. The combination of dieldrin and H2O2 further pronounced these effects. TPEN, a chelator of intracellular Zn(2+), significantly attenuated the synergistic increase in cell lethality induced by dieldrin and H2O2. It is, therefore, suggested that dieldrin augments the cytotoxicity of H2O2 in a Zn(2+)-dependent manner.

Effect of polyphenols on oxymyoglobin oxidation: prooxidant activity of polyphenols in vitro and inhibition by amino acids

Effects of various plant phenolics, including polyphenols, on the oxidation of oxymyoglobin were investigated. Most phenolics promoted the oxidation of oxymyoglobin at both pH 5.4 and 7.4. Potent oxidation-promoting activity was observed by several efficient antioxidant polyphenols with a catechol moiety. Therefore, effects of the catechol structure were investigated using dihydrocaffeic acid analogues. The results clarified that ortho- or para-substituted diphenol structures were important for promoting the oxidation of oxymyoglobin. Inhibition of such prooxidant activity for oxymyoglobin by dihydrocaffeic acid was also investigated. Although the required concentration was relatively higher than that of dihydrocaffeic acid, several amino acids inhibited the oxidation. Among these, cysteine was the most potent. Although cysteine alone completely inhibited oxidation at a concentration above 1 mmol/L, 0.1 mmol/L cysteine showed oxidation-promoting activity. In the presence of 0.1 mmol/L dihydrocaffeic acid, in the range of 0.01 mmol/L to 1 mmol/L cysteine, 0.1 mmol/L cysteine showed the most efficient inhibition. These results suggest the possibility of the formation of some equimolar complexes of dihydrocaffeic acid and cysteine such as 5'-cysteinyl dihydrocaffeic acid, which may be produced during the prooxidation of dihydrocaffeic acid, contributing to the inhibition of the oxidation of oxymyoglobin.

Analysis of cytokines in the early development of gastric secondary lymphoid follicles in Helicobacter pylori-infected BALB/c mice with neonatal thymectomy

Immunological interaction between the host and Helicobacter pylori seems to play a critical role in follicular formation in gastric mucosa. We reported H. pylori-induced follicular gastritis model using neonatally thymectomized mice. In this study, we investigated the involvement of various cytokines in this model. BALB/c mice were thymectomized on the third day after birth (nTx). At 6 weeks old, these mice were orally infected with H. pylori. Histological studies showed that follicular formation occurred from 8 weeks after the infection and that most of the infiltrating lymphocytes were CD4(+) and B cells. Neutrophils increased transiently at 1 week after the infection. Gamma interferon, interleukin-7 (IL-7), and IL-7 receptor were expressed in the stomach of the nTx mice irrespective of the infection. In contrast, expressions of the tumor necrosis factor alpha, IL-4 and lymphotoxin-alpha genes were remarkably upregulated by the infection. Our findings suggest that follicular formation may require cooperative involvement of a Th2-type immune response, tumor necrosis factor alpha and lymphotoxin-alpha in addition to the Th1-type immune response in H. pylori-induced gastritis in nTx mice.

Telomerase activity of the Lugol-stained and -unstained squamous epithelia in the process of oesophageal carcinogenesis

Up-regulation of telomerase has been reported in many cancers. Our aim was to characterize telomerase activity in various states of the oesophagus to facilitate better understanding of carcinogenesis of oesophageal squamous cell carcinoma. During endoscopic examinations, we obtained 45 Lugol-stained normal epithelia, 31 Lugol-unstained epithelia (14 oesophagitis, 7 mild dysplasia, 5 severe dysplasia and 5 intramucosal cancer) and 9 advanced cancer. Telomerase activity was semi-quantified by a telomeric repeat amplification protocol using enzyme-linked immunosorbent assay, and expression of human telomerase reverse transcriptase mRNA was examined by in situ hybridization. In the Lugol-stained normal epithelia, telomerase activity increased in proportion to the increase of severity of the accompanying lesions, with a rank order of advanced cancer, intramucosal cancer, mild dysplasia and oesophagitis. In the Lugol-unstained lesions and advanced cancer, telomerase activity was highest in advanced cancer. Up-regulation of telomerase in normal squamous epithelium may be a marker of progression of oesophageal squamous cell carcinoma.

Autoimmune-related pancreatitis is associated with autoantibodies and a Th1/Th2-type cellular immune response

BACKGROUND & AIMS

Although autoimmunity may be involved in some cases of pancreatitis, the mechanism is still unknown. To clarify this, we studied serum autoantibodies, subsets of lymphocytes, and the Th1/Th2 balance of cellular immune responses in patients with autoimmune-related pancreatitis (AIP).

METHODS

Seventeen patients with AIP (8 men and 9 women; age, 53.2 +/- 13.0 years) were studied. Autoantibodies including antilactoferrin (ALF) or carbonic anhydrase II antibody (ACA-II) were examined using the enzyme-linked immunosorbent assay (ELISA) or the indirect fluorescein antibody method. Intracellular cytokines (interferon gamma and interleukin 4) and subtypes of peripheral blood lymphocytes were examined by flow cytometry and ELISA.

RESULTS

More than one autoantibody was observed in all 17 patients. Serum antinuclear antibody was detected in 13 of 17 patients, ALF antibody in 13, ACA-II antibody in 10, rheumatoid factor in 5, and anti-smooth muscle antibody in 3, but antimitochondrial antibody in none. The serum levels of ACA-II and LF antibody were not correlated. HLA-DR(+)CD8(+) and HLA-DR(+)CD4(+) cells were significantly increased in peripheral blood (P < 0.05). CD4(+) cells producing interferon gamma and the secreted levels were significantly increased compared with those in controls (P < 0.05), but interleukin 4 was not increased.

CONCLUSIONS

An autoimmune mechanism against CA-II or LF, and Th1-type immune response, may be involved in AIP.

Pharmacokinetics of cisplatin in analbuminemic rats

The effect of protein binding on the pharmacokinetics of cisplatin (cis-diamminedichloroplatinum (II); CDDP) has been studied in analbuminemic rats, which genetically lack albumins, in comparison with normal rats. CDDP was reported to highly bind to serum components, and the major binder was thought to be an albumin. However, there were no significant differences in the serum disappearance profiles of platinum after intravenous (iv) bolus injection of CDDP to analbuminemic rats as compared with normal rats. The total body clearance, Cl(tot), of platinum in normal rats was 48.7+/-22.0 mL h(-1) (5 mg kg(-1)), 55.9+/-4.04 mL h(-1) (10 mg kg(-1)) and 49.0+/-3.57 mL h(-1) (20 mg kg(-1)), whereas Cl(tot) in analbuminemic rats was 52.0+/-8.48 mL h(-1) (5 mg kg(-1)), 62.9+/-10. 8 mL h(-1) (10 mg kg(-1)) and 62.8+/-6.81 mL h(-1) (20 mg kg(-1)). The serum blood urea nitrogen (BUN) and creatinine levels at 6 h after iv injection were higher in both groups of rats who received CDDP than those of pre-dose level. However, there were no significant differences in the renal function tests between analbuminemic rats and normal rats. The binding of CDDP to the serum samples obtained from analbuminemic rats and normal rats was measured by a centrifuging filtration method. The binding percentages were 68.0+/-5.9% (2.0 microg mL(-1)), 56.8+/-4.1% (5.0 microg mL(-1)) and 64.6+/-4.4% (10.0 microg mL(-1)) in analbuminemic rats and 52.9+/-3.5% (2.0 microg mL(-1)), 52.2+/-3.4% (5.0 microg mL(-1)), 56.9+/-1.9% (10.0 microg mL(-1)) in normal rats. Higher binding percentages were obtained in analbuminemic rats than in normal rats. In vitro binding studies under the two incubation conditions (5 min and 2 h) showed that the binding percentages of CDDP to serum proteins were 59.2+/-3.2% (5 min) and 72.3+/-6.5% (2 h) for albumin, 42.3+/-1.9% (5 min) and 39.5+/-2.5% (2 h) for alpha(1)-acid glycoprotein (AAG) and 51.7+/-5.3% (5 min) and 49. 2+/-1.9% (2 h) for gamma-globulin. From these studies, it was elucidated that albumin is not the major ligand in the rat serum and that other proteins also have important roles in the pharmacokinetics of CDDP.

Actinic keratoses arising only on sun-exposed vitiligo skin

A 71-year-old woman with vitiligo developed multiple actinic keratoses only on the vitiligo skin of sun-exposed areas. She had worked outdoors as a farmer for a long period. Although actinic skin cancers arising on vitiligo skin have rarely been reported, the present case demonstrates that vitiligo skin is more susceptible to actinic damage than normal skin. Patients with vitiligo should be well informed about the importance of sun protection.

Endosonographic characterization of duodenal elevated lesions

BACKGROUND

Endoscopic diagnosis of duodenal elevated lesions is problematic for two reasons. Endoscopic biopsy often fails to confirm a histologic diagnosis of submucosal lesions. Moreover, a biopsy specimen is often insufficient to verify a differential diagnosis of mucosal lesions. In this study, we evaluated the usefulness of endosonography in the resolution of these problems.

METHODS

The endoscopic and endosonographic features of 15 duodenal elevated lesions that had been confirmed histologically in our hospital were reviewed retrospectively.

RESULTS

Of the 15 cases, 8 were submucosal lesions (lipoma, Brunner's gland hyperplasia, lymphangioma, carcinoid tumors, leiomyoma, and malignant lymphoma); the rest were mucosal lesions. A correct histologic diagnosis based on endoscopic biopsies was obtained in only 6 cases (three submucosal lesions and three mucosal lesions). On the other hand, ultrasonography was useful in the characterization of all submucosal lesions based on their echo level, layer of origin, and tissue homogeneity. As for mucosal lesions, the depth of infiltration was correctly estimated with endosonography. Either endoscopic resection or surgery was selected on the basis of endosonographic information.

CONCLUSIONS

We conclude that endosonography is useful in the differential diagnosis of submucosal lesions and in determining suitable treatment methods for duodenal mucosal and submucosal lesions.

Vitrification of bovine embryos in a mixture of ethylene glycol and dimethyl sulfoxide

The influence of equilibration time before vitrification on the viability of vitrified morula- to blastocyst-stage bovine embryos and in vivo viability of vitrified embryos following transfer to recipients were investigated. In experiment 1, the embryos were exposed to an equilibration solution (50% VSED) containing 12.5% v/v ethylene glycol and 12.5% v/v dimethyl sulfoxide in modified Dulbecco's phosphate buffered saline with 4 mg/ml BSA (m-PBS) for 1, 2 and 5 minutes at room temperature (22 to 24 degrees C). The embryos were then placed in 15mul vitrification solution (VSED) consisting of 25% v/v ethylene glycol and 25% v/v dimethyl sulfoxide in m-PBS and were loaded into 0.25 ml plastic straws at room temperature. After 30 seconds, the straws were placed in liquid nitrogen (LN(2)) vapor for 2 minutes, plunged and stored in LN(2). To thaw, the straws were warmed in water at 20 degrees C for 15 seconds and the contents of the straws were expelled into a plastic dish. The embryos were diluted in 0.5 M sucrose + m-PBS for 5 minutes and were cultured in TCM-199 supplemented with bovine oviductal epithelial tissue. Viability of the embryos was assessed by the forming or reforming of the blastocoele after 24 hours of culture. High in vitro survival rates (73 approximately 90%) of vitrified embryos were obtained after 1 and 2 minute equilibrations, but was reduced (P<0.05) after 5 minute equilibration. In Experiment 2, morula- to blastocyst-stage embryos were vitrified after 1 minute equilibration in 50% VSED and 30 seconds of exposure to VSED. The vitrified-warmed embryos were transferred to recipient heifers at 7 days after estrus (1 embryo per recipient). Five (38%) of 13 (40%) of 10 recipients that had received blastocysts were diagnosed as pregnant using ultrasonography 60 days following transfer.

Hidroacanthoma simplex showing variation in the appearance of tumor cells in different nests

We report a case of hidroacanthoma simplex on the inframammary area of an 86-year-old woman. The tumor cells showed considerable variation in appearance in different nests from the same lesion. By light and electron microscopy 5 types of tumor cells were identified. This tumor was thought to originate from the outer cells of the intraepidermal eccrine duct.