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31.
Mechanical properties in the human gastric antrum using B-mode ultrasonography and antral distension
Gregersen H Gilja OH Hausken T Heimdal A Gao C Matre K Ødegaard S Berstad A 《American journal of physiology. Gastrointestinal and liver physiology》2002,283(2):G368-G375
The aims of this study were to investigate gastric antral geometry and stress-strain properties by using transabdominal ultrasound scanning during volume-controlled distensions in the human gastric antrum. Seven healthy volunteers underwent stepwise inflation of a bag located in the antrum with volumes up to 60 ml. The stretch ratio and Cauchy stress and strain were calculated from measurements of pressure, diameter, and wall thickness. A second distension series was conducted in three volunteers during administration of the anticholinergic drug butylscopolamine. Analysis of stretch ratios demonstrated positive strain in the circumferential direction, negative strain in the radial direction, and no strain in the longitudinal direction. The stress-strain relation was exponential and did not differ without or with the administration of butylscopolamine. The wall stress was decomposed into its active and passive components. The well-known length-tension diagram from in vitro studies of smooth muscle strips was reproduced. The maximum active tension appeared at a volume of 50 ml, corresponding to a stretch ratio of 1.5. We conclude that the method provides measures of antral biomechanical wall properties and can be used to reproduce the muscle length-tension diagram in humans. 相似文献
32.
Anveden Å Sjöholm K Jacobson P Palsdottir V Walley AJ Froguel P Al-Daghri N McTernan PG Mejhert N Arner P Sjöström L Carlsson LM Svensson PA 《Obesity (Silver Spring, Md.)》2012,20(4):708-714
Adipocytes secrete many proteins that regulate metabolic functions. The gene inter-α (globulin) inhibitor H5 (ITIH-5) encodes a secreted protein and is known to be expressed abundantly in the placenta. However, using gene expression profiles data we observed high expression of ITIH-5 in adipose tissue. The aim of this study was to test the hypothesis that ITIH-5 is strongly expressed in human adipocytes and adipose tissue, and is related to obesity and clinical metabolic variables. ITIH-5 adipose tissue mRNA expression was analyzed with DNA microarray and real-time PCR, and its association with clinical variables was examined. ITIH-5 protein expression was analyzed using western blot. ITIH-5 mRNA expression was abundant in human adipose tissue, adipocytes, and placenta, and higher in subcutaneous (sc) compared to omental adipose tissue (P < 0.0001). ITIH-5 mRNA and protein expression in sc adipose tissue were higher in obese compared to lean subjects (P < 0.0001 and P < 0.001, respectively). ITIH-5 mRNA expression was reduced after diet-induced weight loss (P < 0.0001). ITIH-5 mRNA expression was associated with anthropometry and clinical metabolic variables. In conclusion, ITIH-5 is highly expressed in sc adipose tissue, increased in obesity, down regulated after weight loss, and associated with measures of body size and metabolism. Together, this indicates that ITIH-5 merits further investigation as a regulator of human metabolism. 相似文献
33.
Protein phosphatase 2A (PP2A) is a serine/threonine-specific phosphatase comprising a catalytic subunit (C), a scaffolding
subunit (A), and a regulatory subunit (B). The B subunits are believed to be responsible for substrate specificity and localization
of the PP2A complex. In plants, three families of B subunits exist, i.e. B (B55), B′, and B′′. Here, we report differential
subcellular targeting within the Arabidopsis B′η subfamily, which consists of the close homologs B′η, B′θ, B′γ and B′ζ. Phenotypes of corresponding knockouts were observed,
and particularly revealed delayed flowering for the B′η knockout. The B′ subunits were linked to fluorescent tags and transiently
expressed in various tissues of onion, tobacco and Arabidopsis. B′η and B′γ targeted the cytosol and nucleus. B′ζ localized to the cytoplasm and partly co-localized with mitochondrial
markers when the N-terminus was free. Provided its C-terminus was free, the B′θ subunit targeted peroxisomes. The importance
of the C-terminal end for peroxisomal targeting was further confirmed by truncation of the C-terminus. The results revealed
that the closely related B′ subunits are targeting different organelles in plants, and exemplify the usage of the peptide
serine–serine–leucine as a PTS1 peroxisomal signaling peptide. 相似文献