Effect of traditional floor sitting on postural control after standing

Seiza is a Japanese traditional floor sitting style, sitting down with both legs set at about a 180 degree angle and both femurs on both lower legs. We examined the influence of the somatic dysesthesia and decrease in voluntary toe flexion strength (VTF) induced by Seiza on the center of pressure (COP) sway. Fifteen adults participated in this experiment. COP Sway was measured immediately after a chair resting (pre-test), when a plantar dysethesia occurred (post-test A), and when a decrease (under 30% of maximal voluntary contraction (MVC)) in the VTF set in (post-test B). Tissue oxygenation kinetics in the soleus muscle and plantar somatosensory thresholds (ST) were measured just before each COP test and during Seiza. From starting Seiza, oxygenated hemoglobin/myoglobin decreased markedly and reached a plateau within about 6 min. ST abruptly increased at about 19 min from starting Seiza. VTF decreased to less than 30% MVC in 33% of the participants after 10 min from the acute increase in ST, and in 100% after 20 min. When sustaining Seiza for 19 min, ST rose and sway velocity and antero-posterior sway increased. With continued Seiza, VTF decreased to below 30% MVC at 10 - 20 min, and the above stated body sway further markedly increase.     

Mevastatin induces apoptosis in HL60 cells dependently on decrease in phosphorylated ERK

Mevastatin which is an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in cholesterol synthesis, suppress cell proliferation and induce apoptosis. However, the molecular mechanism of apoptosis induction is not well understood. So, in the present study, we attempted to clarify the mechanism by which mevastatin induces apoptosis in HL60 cells. It was found that mevastatin induced apoptosis. At that time, we observed an increase in caspase-3 activity and morphological fragmentation of the nuclei. The apoptosis induced by mevastatin was not inhibited by the addition of farnesyl pyrophosphate (FPP), squalene, ubiquinone, and isopentenyladenine, but was inhibited by the addition of geranylgeranyl pyrophosphate (GGPP). When we examined the survival signals at the time of apoptotic induction, we also observed that the administration of mevastatin had caused a remarkable decrease in the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). However, other survival signals, such as nuclear factor kappa B (NF-kappaB), protein kinase B (Akt), and p38 mitogen-activated protein kinase (p38), exhibited no change. In addition, no quantitative change was observed in Bcl-2, which was an anti-apoptosis protein. It was also observed that apoptosis was induced when U0126, an MEK inhibitor, was added to the cells to inhibit ERK. These results suggested that mevastatin induced apoptosis when it inhibited GGPP biosynthesis and consequently decreased the level of phosphorylated ERK, which was a survival signal; moreover, at that time, there was no influence on NF-kappaB, Akt, p38, and Bcl-2. The results of this study also suggested that mevastatin could be used as an anticancer agent.     

Mevastatin induces apoptosis in HL60 cells dependently on decrease in phosphorylated ERK

Mevastatin which is an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in cholesterol synthesis, suppress cell proliferation and induce apoptosis. However, the molecular mechanism of apoptosis induction is not well understood. So, in the present study, we attempted to clarify the mechanism by which mevastatin induces apoptosis in HL60 cells. It was found that mevastatin induced apoptosis. At that time, we observed an increase in caspase-3 activity and morphological fragmentation of the nuclei. The apoptosis induced by mevastatin was not inhibited by the addition of farnesyl pyrophosphate (FPP), squalene, ubiquinone, and isopentenyladenine, but was inhibited by the addition of geranylgeranyl pyrophosphate (GGPP). When we examined the survival signals at the time of apoptotic induction, we also observed that the administration of mevastatin had caused a remarkable decrease in the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). However, other survival signals, such as nuclear factor kappa B (NF-B), protein kinase B (Akt), and p38 mitogen-activated protein kinase (p38), exhibited no change. In addition, no quantitative change was observed in Bcl-2, which was an anti-apoptosis protein. It was also observed that apoptosis was induced when U0126, an MEK inhibitor, was added to the cells to inhibit ERK. These results suggested that mevastatin induced apoptosis when it inhibited GGPP biosynthesis and consequently decreased the level of phosphorylated ERK, which was a survival signal; moreover, at that time, there was no influence on NF-B, Akt, p38, and Bcl-2. The results of this study also suggested that mevastatin could be used as an anticancer agent. (Mol Cell Biochem 269: 109–114, 2005)     

Tissue distribution, synthesis stage, and ethylene induction of pineapple (Ananas comosus) chitinases

We examined the tissue distribution, synthesis stage, and ethylene induction of three types of pineapple chitinase using chitinase activity gel and immunoblot analysis. Type A (acidic class III) exists in all tissues, while type B (weakly basic class I, which has strong antifungal activity) and type C (acidic class I) are localized mainly in the leaf and stem. In a pericarp, type A exists at all stages during fruit development, while type B and type C exist only at the early stage. Synthesis of type A is induced by ethylene, while that of types B and C is not affected by it. These results suggest that the physiological roles of these three types of chitinase in pineapple are different.     

Prenatal blockage of lymphotoxin beta receptor and TNF receptor p55 signaling cascade resulted in the acceleration of tissue genesis for isolated lymphoid follicles in the large intestine

Signaling by lymphotoxin (LT) and TNF is essential for the organogenesis of secondary lymphoid tissues in systemic and mucosal compartments. In this study, we demonstrated that the progeny of mice treated with fusion protein of LTbetaR and IgGFc (LTbetaR-Ig) or LTbetaR-Ig plus TNFR55-Ig (double Ig) showed significantly increased numbers of isolated lymphoid follicles (ILF) in the large intestine. Interestingly, double Ig treatment accelerated the maturation of large intestinal ILF. Three-week-old progeny of double Ig-treated mice showed increased numbers of ILF in the large intestine, but not in the small intestine. Furthermore, alteration of intestinal microflora by feeding of antibiotic water did not affect the increased numbers of ILF in the large intestine of double Ig-treated mice. Most interestingly, mice that developed numerous ILF also had increased levels of activation-induced cytidine deaminase expression and numbers of IgA-expressing cells in the lamina propria of the large intestine. Taken together, these results suggest that ILF formation in the large intestine is accelerated by blockage of LTbetaR and TNFR55 signals in utero, and ILF, like colonic patches, might play a role in the induction of IgA response in the large intestine.     

Inhibitory effects of trientine, a copper-chelating agent, on induction of DNA strand breaks in hepatic cells of Long-Evans Cinnamon rats

Effects of treatment with trientine, a specific copper-chelating agent, on accumulation of copper and induction of DNA strand breaks were investigated in Long-Evans Cinnamon (LEC) rats, an animal model for human Wilson's disease. Copper accumulated in the livers of LEC rats in an age-dependent manner from 4 to 13 weeks of age. When LEC rats were treated with trientine from 10 weeks of age, hepatic copper contents did not increase and were maintained at the same levels as those in 10-week-old LEC rats. When the amounts of DNA single-strand breaks (SSBs) were estimated by a comet assay, SSBs of DNA were induced in a substantial population of LEC rat hepatic cells around 8 weeks of age and the amounts of SSBs increased in an age-dependent manner from 8 to 15 weeks of age. When LEC rats were treated with trientine from 10 weeks of age, the observed number of cells with DNA damage decreased dramatically, suggesting that induction of SSBs of DNA was inhibited and/or SSBs were repaired during the period of treatment with trientine. The results show that treatment of LEC rats with trientine decreases the number of DNA strand breaks observed, although copper contents remain high in the liver.     

Persistence of gene expression changes in stomach mucosae induced by short-term N-methyl-N'-nitro-N-nitrosoguanidine treatment and their presence in stomach cancers

Cancers induced by different carcinogens show distinct expression profiles. In addition to the specific alterations of tumor-related genes induced by specific carcinogens, it is possible that some initial responses induced by a carcinogen could persist for long periods and are consistently present in the cancers induced. We have analyzed the initial responses in the rat pyloric mucosae after treatment for 2 weeks with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Gene expression was monitored 1 day, 2 weeks and 4 weeks after MNNG treatment by oligonucleotide microarray analysis. Of the differentially expressed genes showing greater than three-fold difference 1 day after MNNG treatment, 143 and 26 genes were up- and down-regulated, respectively, in MNNG-induced stomach cancers. Among these genes, 25 and 6 genes were up- and down-regulated, respectively, in the histologically normal pyloric mucosae, even 4 weeks after cessation of MNNG treatment. Among the up-regulated genes, many genes involved in tissue remodeling (Spi15, Serpine1 and Fst) and cellular growth (Bdnf, Ros1 and Fgf10) were present. The six down-regulated genes included TGF-beta-inducible early growth response gene. These findings demonstrate that some expression changes induced by MNNG persist for a prolonged period and are present in cancers. Persistent expression changes are considered to be important for prediction of past carcinogen exposure, and could provide a molecular environment favorable for malignant transformation.     

Evidence of the existence of a toxic form of Cylindrospermopsis raciborskii (Nostocales,Cyanobacteria) in Japan

Cylindrospermopsis raciborskii is a common, bloom‐forming, planktonic, freshwater cyanobacterium. Toxic populations producing cylindrospermopsin can cause water‐safety problems. Although C. raciborskii is distributed worldwide, the presence of cylindrospermopsin‐producing strains of C. raciborskii was initially reported only in Australia and recently in Thailand. Here, we report the isolation of a toxic strain of C. raciborskii (ISG9) from a freshwater sample collected in Okinawa in 2008. This is the first report describing toxin expression in this species in Japan, detected from a subtropical area. The C. raciborskii species is known to produce cylindrospermopsin as a dominant toxin; however, in this new isolate, the dominant toxin expressed was deoxy‐cylindrospermopsin. The discovery of a toxic strain of C. raciborskii in southern Japan emphasizes the need for basic monitoring schemes for this species in water supplies located in the temperate regions of Japan because of its possible expansion and distribution to other geographic areas.     

Claudin-4 Deficiency Results in Urothelial Hyperplasia and Lethal Hydronephrosis

Claudin (Cld)-4 is one of the dominant Clds expressed in the kidney and urinary tract, including selective segments of renal nephrons and the entire urothelium from the pelvis to the bladder. We generated Cldn4 ^−/− mice and found that these mice had increased mortality due to hydronephrosis of relatively late onset. While the renal nephrons of Cldn4 ^−/− mice showed a concomitant diminution of Cld8 expression at tight junction (TJ), accumulation of Cld3 at TJ was markedly enhanced in compensation and the overall TJ structure was unaffected. Nonetheless, Cldn4 ^−/− mice showed slightly yet significantly increased fractional excretion of Ca²⁺ and Cl⁻, suggesting a role of Cld4 in the specific reabsorption of these ions via a paracellular route. Although the urine volume tended to be increased concordantly, Cldn4 ^−/− mice were capable of concentrating urine normally on dehydration, with no evidence of diabetes insipidus. In the urothelium, the formation of TJs and uroplaques as well as the gross barrier function were also unaffected. However, intravenous pyelography analysis indicated retarded urine flow prior to hydronephrosis. Histological examination revealed diffuse hyperplasia and a thickening of pelvic and ureteral urothelial layers with markedly increased BrdU uptake in vivo. These results suggest that progressive hydronephrosis in Cldn4 ^−/− mice arises from urinary tract obstruction due to urothelial hyperplasia, and that Cld4 plays an important role in maintaining the homeostatic integrity of normal urothelium.