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51.
52.
Aehyun Kwon Masako Kato Hiroko Kawamura Yuichi Yanai Hiromi Tokura 《European journal of applied physiology and occupational physiology》1998,78(6):487-493
The purpose of this present study was to compare the physiological effects of the hydrophilic and hydrophobic properties
of the fabrics investigated in exercising and resting subjects at an ambient temperature of 30°C and a relative humidity of
50% with and without wind. Three kinds of clothing ensemble were tested: wool and cotton blend with high moisture regain (A),
100% cotton with intermediate moisture regain (B), 100% polyester clothing with low moisture regain (C). The experiments were
performed using seven young adult women as subjects. They comprised six repeated periods of 10-min exercise on a cycle ergometer
at an intensity of 40% maximal oxygen uptake followed by 5 min of rest (20 min for the last rest). The experiments comprised
two sessions. During session I (first three repetitions of exercise and rest) the subjects were exposed to an indifferent
wind velocity and during session II (last three repetitions of exercise and rest) they were exposed to a wind velocity of
1.5 m · s−1. Rectal temperature and skin temperatures at eight sites, pulse rate and clothing microclimate were recorded throughout the
whole period. The main findings can be summarized as follows: rectal temperature during session II was kept at a significantly
lower level in A than in B and C. Clothing microclimate humidity at the chest was significantly lower in A than in B and C
during session II. Skin and clothing microclimate temperatures at the chest were significantly lower in A than in B and C
during session II. Pulse rate was significantly higher in C than in A and B during sessions I and II. It was concluded that
the hydrophilic properties of the fabrics studied were of physiological significance for reducing heat strain during exercise
and rest especially when influenced by wind.
Accepted: 3 June 1998 相似文献
53.
54.
In many organisms, trehalose protects against several environmental stresses, such as heat, desiccation, and salt, probably by stabilizing protein structures and lipid membranes. Trehalose synthesis in yeast is mediated by a complex of trehalose-6-phosphate synthase (TPS1) and trehalose-6-phosphate phosphatase (TPS2). In this study, genes encoding TPS1 and TPS2 were isolated from Zygosaccharomyces rouxii (designated ZrTPS1 and ZrTPS2, respectively). They were functionally identified by their complementation of the tps1 and tps2 yeast deletion mutants, which are unable to grow on glucose medium and with heat, respectively. Full-length ZrTPS1 cDNA is composed of 1476 nucleotides encoding a protein of 492 amino acids with a molecular mass of 56 kDa. ZrTPS2 cDNA consists of 2843 nucleotides with an open reading frame of 2700 bp, which encodes a polypeptide of 900 amino acids with a molecular mass of 104 kDa. The amino acid sequence encoded by ZrTPS1 has relatively high homology with TPS1 of Saccharomyces cerevisiae and Schizosaccharomyces pombe, compared with TPS2. Western blot analysis showed that the antibody against S. cerevisiae TPS1 recognizes ZrTPS1. Under normal growth conditions, ZrTPS1 and ZrTPS2 were highly and constitutively expressed, unlike S. cerevisiae TPS1 and TPS2. Salt stress and heat stress reduced the expression of the ZrTPS1 and ZrTPS2 genes, respectively. 相似文献
55.
The role of interleukin-4 (IL-4) in the inflammatory process has emerged recently. In this study, we investigated the effect of IL-4 on the angiogenic process in an in vitro experimental system. IL-4 significantly inhibited the proliferation of human umbilical vein endothelial cells (HUVEC) that was induced by the vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). VEGF- or bFGF-induced HUVEC chemotaxis was abrogated by the IL-4 treatment. In addition, the formation of tube-like structures by HUVEC in the presence of VEGF or bFGF was also severely down-regulated by IL-4. The inhibitory effects on the critical steps of angiogenesis were not observed with IL-6 that is abundantly found in the inflamed tissue. Our results suggest that IL-4 may play a regulatory role in normal physiology and provide the potential possibility for IL-4 as a therapeutic agent in the intervention of angiogenesis-related diseases. 相似文献
56.
57.
Bae JH Mun KC Park WK Lee SR Suh SI Baek WK Yim MB Kwon TK Song DK 《Biochemical and biophysical research communications》2002,290(5):1506-1512
We have investigated the protective effect of (-)-epigallocatechin gallate (EGCG) on alpha-amino-3-hydroxy-5-methyl-4-isoxazolo propionate (AMPA)-induced toxicity in cultured rat hippocampal neurons. Treatment of 24 h AMPA (10 microM) reduced the neuronal viability in both survival neuron counting and MTT reduction assay compared with control, with increase in cellular concentrations of hydrogen peroxide and malondialdehyde. These responses to AMPA were significantly blocked by co-treatments with EGCG (10 microM), which effect was very similar to the protective ability of a known antioxidant catalase (2000 U/ml). AMPA (50 microM) elicited the increase in intracellular calcium concentration ([Ca(2+)]i) on which EGCG significantly attenuated both peak amplitude and sustained nature of that [Ca(2+)]i increase in a dose-dependent manner. These data suggest that EGCG has a neuroprotective effect against AMPA through inhibition of AMPA-induced [Ca(2+)]i increase and consequent attenuation of reactive oxygen species production and lipid peroxidation as an antioxidant and a radical scavenger. 相似文献
58.
The enhanced reactivity of endogenous biotin-like molecules by antigen retrieval procedures and signal amplification with tyramine 总被引:2,自引:0,他引:2
Kim SH Jung KC Shin YK Lee KM Park YS Choi YL Oh KI Kim MK Chung DH Son HG Park SH 《The Histochemical journal》2002,34(3-4):97-103
In diagnostic pathology and immunocytochemical research, immunohistochemical techniques using the streptavidin–biotin–peroxidase system have played an extremely valuable role. This system, based on the high affinity of streptavidin for biotin, may, however, provoke false positive results because of endogenous streptavidin-binding sites in human tissues. With the advent of the antigen retrieval procedure and signal amplification method, this problem can be serious enough to cause mistakes in interpreting immunohistochemical staining results. Therefore, we examined the distribution of endogenous biotin-like molecules in various human tissues and the influence of various antigen retrieval procedures with or without signal amplification using biotinylated tyramine to reveal these biotin-like activities. We observed that endogenous biotin-like molecules were present in a wide range of tissues, and their activity was markedly enhanced by employing antigen retrieval procedures or signal amplification. Furthermore, the extent to which the activity of endogenous biotin-like activities was enhanced depended on the kinds of antigen retrieval procedures and signal amplification employed. Pressure cooking and tyramine amplification with microwave heating showed the highest activities. These results show that the antigen retrieval procedures and signal amplification with tyramine can enhance the activity of endogenous biotin or biotin-like molecules as well as antigenicity, which can be a pitfall in the interpretation of immunohistochemical data. 相似文献
59.
Three-dimensional cellular deformation analysis with a two-photon magnetic manipulator workstation 下载免费PDF全文
The ability to apply quantifiable mechanical stresses at the microscopic scale is critical for studying cellular responses to mechanical forces. This necessitates the use of force transducers that can apply precisely controlled forces to cells while monitoring the responses noninvasively. This paper describes the development of a micromanipulation workstation integrating two-photon, three-dimensional imaging with a high-force, uniform-gradient magnetic manipulator. The uniform-gradient magnetic field applies nearly uniform forces to a large cell population, permitting statistical quantification of select molecular responses to mechanical stresses. The magnetic transducer design is capable of exerting over 200 pN of force on 4.5-microm-diameter paramagnetic particles and over 800 pN on 5.0-microm ferromagnetic particles. These forces vary within +/-10% over an area 500 x 500 microm2. The compatibility with the use of high numerical aperture (approximately 1.0) objectives is an integral part of the workstation design allowing submicron-resolution, three-dimensional, two-photon imaging. Three-dimensional analyses of cellular deformation under localized mechanical strain are reported. These measurements indicate that the response of cells to large focal stresses may contain three-dimensional global deformations and show the suitability of this workstation to further studying cellular response to mechanical stresses. 相似文献
60.
Suh YH Kim MK Shin YK Kim SH Oh KI Gil M Kim MK Choi YL Jung KC Lee KM Lee IS Park SH 《Molecules and cells》2002,13(2):237-244
Hodgkin's disease (HD) is a lymphoid neoplasm characterized by a low frequency of malignant giant tumor cells, known as Hodgkin's and Reed-Sternberg (HRS) cells. Sequence analysis of the immunoglobulin heavy chain hypervariable region (IgH V) genes of HRS cells revealed multiple nucleotide substitutions, indicating somatic mutations, and suggested that HRS cells originate from germinal center B cells or their progeny. We previously reported that CD99-antisense transfected B cell lines led to the generation of cells with a HRS phenotype. Because it is considered that HRS cells in HD carry somatic mutations of the IgH genes, we assume that somatic mutation may take place in the IgH genes of HRS-like cells which do not express CD99. Here we report that CD99 downregulated BJAB cell line has several mutations in IgH V genes. The frequency of mutation was 5.2 x 10(-4) mut.bp(-1) out of total sequenced cell clones. On the contrary, control vector transfected BJAB cell line or CD99 downregulated IM9 cell line did not show any mutations on single strand conformational polymorphism (SSCP) and sequence analysis. We expect that the analysis of the mutation pattern of the CD99-deficient BJAB cell line might be the basis for the understanding of the molecular and cellular mechanism that regulate somatic mutation and B cell selection. 相似文献