Nippon Eiyo Shokuryo Gakkaishi
Online ISSN : 1883-2849
Print ISSN : 0287-3516
ISSN-L : 0287-3516
Volume 64, Issue 4
Displaying 1-5 of 5 articles from this issue
Reviews
  • (Young Investigator Award of JSNFS (2010))
    Hideo Satsu
    2011 Volume 64 Issue 4 Pages 207-214
    Published: 2011
    Released on J-STAGE: October 18, 2011
    JOURNAL FREE ACCESS
    Intestinal epithelial cells (IECs) have various functions, including absorption of food substances, immune functions such as cytokine secretion, and barrier function against xenobiotics involving drug metabolizing enzymes. In this study, we examined the absorption mechanism of food factors in IECs and also the effect of food factors on the function of IECs mainly at the cellular level. We found that various food factors permeate across the IEC monolayer via transporters, the paracellular route, and transcellular passive diffusion, respectively. On the other hand, intestinal transporter activity was regulated by other food factors. We developed an in vitro model of inflammatory bowel disease using intestinal epithelial Caco-2 cells and macrophage-like THP-1 cells, and applied it for screening and analysis of anti-inflammatory food factors. It was also revealed that the secretion of interleukin-8 from IECs was suppressed by food factors that prevented intestinal inflammation in vivo. Furthermore, several phytochemicals were shown to induce the expression and activity of drug metabolizing enzymes in IECs via activation of nuclear receptors such as the pregnane X receptor. These findings related to the interaction between IECs and food factors at the cellular and molecular levels are important for understanding the molecular mechanism of absorption and the physiological function of food factors.
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  • (Young Investigator Award of JSNFS (2010))
    Masashi Kuwahata
    2011 Volume 64 Issue 4 Pages 215-219
    Published: 2011
    Released on J-STAGE: October 18, 2011
    JOURNAL FREE ACCESS
    Serum albumin has become an indispensable factor for evaluation of nutritional status. In the regulation of albumin synthesis, stimulation resulting from ingestion of a meal is one of the most important factors. Transcription of the albumin gene is known to be influenced by protein nutrition status, and we have shown that modulation of albumin gene expression by amino acid supply in rat liver is mediated through the intracellular concentration of pyridoxal 5′-phosphate. We suggest that pyridoxal 5′-phosphate interacts directly with a tissue-specific transcription factor and modulates binding to the albumin gene. Post-transcriptional regulation plays an important role in the reduction of albumin synthesis under fasting conditions. Polypyrimidine tract-binding protein (PTB) is an abundant eukaryotic RNA-binding protein. We have shown that binding of PTB to the coding region of albumin mRNA suppresses its translation. We suggest that alterations in the level of the albumin mRNA-PTB complex are involved in the regulation of albumin synthesis in fasted rats.
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  • Keiji Tanaka
    2011 Volume 64 Issue 4 Pages 221-228
    Published: 2011
    Released on J-STAGE: October 18, 2011
    JOURNAL FREE ACCESS
    Proteins, which are the major functional constituents of the cell, show dynamic turnover facilitated by repeated synthesis and destruction, and an infinite variety of life-spans ranging from several minutes to several months; i.e., approximately 3.0% of all proteins are degraded daily. Proteolysis plays an important role not only in the selective disposal of harmful proteins with aberrant structures, but also in the active breakdown of unnecessary proteins whose accumulation would cause defects of cell homeostasis, and of normal proteins when the cell lacks metabolic energy or acquires amino acids for protein synthesis in nutritionally step-down conditions. Over the past 25 years, studies of proteolysis have led to a marked expansion of knowledge, and are still ongoing at the present time, so that proteolysis is currently a focus of interest in the field of life science. We have been aiming to provide a comprehensive picture of the divergent roles of proteolysis. This review summarizes the physiological importance of the protein renewal/recycling system in cell metabolism.
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Original Paper
  • Ritsuna Noguchi, Mami Hiraoka, Yoh Jinnouchi, Hiromi Kitahara, Yoshino ...
    2011 Volume 64 Issue 4 Pages 229-238
    Published: 2011
    Released on J-STAGE: October 18, 2011
    JOURNAL FREE ACCESS
    Observational studies of Japanese healthy subjects have demonstrated an inverse relationship between low levels of folate and depression scores in male subjects. However, few studies have examined folate levels and depressive symptoms among Japanese patients with depression. We examined the association of folate levels with symptoms of depression in Japanese patients. The following variables were assessed in 103 patients (n=60 males, 40.1±11.4 yr; and 43 females, 37.9±12.4 yr) with psychiatric disorders: depressive symptoms; serum levels of folate, homocysteine, and VB12; intakes of folate, VB2, VB6, and VB12; and genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR). Serum folate levels and intakes of folate, VB2, and VB6 showed a significant inverse correlation with psychiatric symptoms in male, but not female, patients. Serum folate levels in females were significantly higher than those in males. Intakes of folate, VB2, and VB6 were significantly higher in females than in males. Among these patients, the frequency of the TT genotype of MTHFR genetic polymorphism, a reported risk factor for depression, did not differ from that of a healthy Japanese population. Folate status is associated with depressive symptoms in male patients.
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Research Note
  • Youichi Arai, Noboru Shirahata, Junichi Fukasawa, Mayuko Tsuchida, Yos ...
    2011 Volume 64 Issue 4 Pages 239-243
    Published: 2011
    Released on J-STAGE: October 18, 2011
    JOURNAL FREE ACCESS
    Ayunohikari, a type of sugary rice, has an inhibitory effect on digestion compared with other rice cultivars due to its resistant structure. The present study investigated the effects of Ayunohikari on postprandial blood glucose concentration and insulin response in comparison with a standard rice, Koshihikari. A randomized single-blind crossover-designed study was conducted using eight healthy male subjects (age 39.0±1.7 y, body mass index 23.3±0.6 kg/m2, fasting blood glucose concentration 96.4±2.1 mg/dL). Postprandial blood glucose and serum insulin concentrations were observed at ∼240 min after ingestion of Ayunohikari or Koshihikari cooked rice containing 55 g of carbohydrate. The incremental area under the curve of the blood glucose concentration for 240 min after ingestion of Ayunohikari was 17.5% (non-significantly) lower than that after ingestion of Koshihikari (p=0.07). The incremental area under the curve of the serum insulin concentration for 240 min after ingestion of Ayunohikari was 41.3% (significantly) lower than that after ingestion of Koshihikari (p<0.01). Our finding suggest that Ayunohikari is a useful rice strain for primary prevention of diabetes.
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