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1.
References: 《生物数学学报》1998,13(4):417-425
1IntroductionPeristalsisIsnow-wellknowntothephyslologlststobeoneofthem8JormechanismforfluidtransportInmanybiologicalsystems.Inpatlcular,peristaltlcmechanismmaybeInvolvedInswal-lowing恤throughtheesophagus,urinetransPOrtfromkidneytobladderthoughuner.Inaddl-tion,perlstaltlcpumpingoccursInmanypracticalapplicationsInvolvingbio-mechanicalsystems.Thestudyofthemechanismofperistalsis,Inbothmechanicalandphysiologicalsituations,hasre-centlybecometheoNectofs。;ent;f;crese。roh.S;nce… 相似文献
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Yang YR Liu SL Qin ZY Liu FJ Qin YJ Bai SM Chen ZY 《Cellular and molecular neurobiology》2008,28(5):737-744
To better understand the pathophysiologic mechanisms underlying Guillain-Barré syndrome (GBS), Comparative proteomic analysis of cerebrospinal fluid (CSF) between patients with GBS (the experiment group) and control subjects suffering from other neurological disorders (the control group) was carried out using two-dimensional gel electrophoresis (2-DE) technique, in combination with matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and database searching to determine abnormal CSF proteins in GBS patients. Image analysis of 2-DE gels silver stained revealed that 10 protein spots showed significant differential expression between the two groups of CSF samples. The expression of cystatin C, transthyretin, apolipoprotein E and heat shock protein 70 were decreased. However, haptoglobin, alpha-1-antitrypsin, apolipoprotein A-IV and neurofilaments were elevated. The subsequent ELISA measured the concentration of cystatin C and confirmed the result of the proteomic analysis. These identified proteins may be involved in the pathophysiological process of GBS and call for further studying the role of these proteins in the pathogenesis of the disease. 相似文献
3.
A model for fluid and drug transport through the leaky neovasculature and porous interstitium of a solid tumour is developed.
The transport problems are posed on a micro-scale characterized by the inter-capillary distance, and the method of multiple
scales is used to derive the continuum equations describing fluid and drug transport on the length scale of the tumour (under
the assumption of a spatially periodic microstructure). The fluid equations comprise a double porous medium, with coupled
Darcy flow through the interstitium and vasculature, whereas the drug equations comprise advection–reaction equations; in
each case the dependence of the transport coefficients on the vascular geometry is determined by solving micro-scale cell
problems. 相似文献
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Jin-Young Kim Seong-Cheol Park Jong-Kook Lee Sang Joon Choi Kyung-Soo Hahm Yoonkyung Park 《PloS one》2012,7(11)
An antibacterial protein (about 12 kDa) was isolated from human amniotic fluid through dialysis, ultrafiltration and C18 reversed-phase HPLC steps. Automated Edman degradation showed that the N-terminal sequence of the antibacterial protein was NH2-Ile-Gln-Arg-Thr-Pro-Lys-Ile-Gln-Val-Tyr-Ser-Arg-His-Pro-Ala-Glu-Asn-Gly-. The N-terminal sequence of the antibacterial protein was found to be identical to that of β2-microglobulin, a component of MHC class I molecules, which are present on all nucleated cells. Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) revealed that the molecular mass of the antibacterial protein was 11,631 Da. This antibacterial protein, β2M, possessed potent antibacterial activity against pathogenic bacteria. Specially, antibacterial activity was observed in potassium buffer, and potassium ion was found to be critical for the antibacterial activity. Interestingly, the antibacterial action of β2M was associated with dissipation of the transmembrane potential, but the protein did not cause damage to the membrane that would result in SYTOX green uptake. In addition, stimulation of WISH amniotic epithelial cells with the bacterial endotoxin lipopolysaccharide (LPS) induced dose-dependent upregulation of β2M mRNA expression. These results suggest that β2M contributes to a self-defense response when amniotic cells are exposed to pathogens. 相似文献
6.
We pyrosequenced the bulk DNA extracted from microorganisms that passed through 0.2-μm-pore-size filters and trapped by 0.1-μm-pore-size
filters in the hydrothermal fluid of the Mariana Trough. Using the 454-FLX sequencer, we generated 202,648 sequences with
an average length of 173.8 bases. Functional profiles were assigned by the SEED Annotation Engine. In the metagenome of the
0.2-μm-passable microorganisms, genes related to membrane function, including potassium homeostasis classified as membrane
transport, and multidrug-resistance efflux pumps classified as virulence, were dominant. There was a higher proportion of
genes pertinent to the subsystem of membrane transport in our metagenomic library than in other oceanic and hydrothermal vent
metagenomes. Genes associated with a RND-type efflux transporter for exogenous substances were specifically identified in
the present study. After a comparative analysis with the genome of the known ultramicrobacterium Sphingopyxis alaskensis RB2256, we discovered 1,542 cases of significant hits (E < 1 × 10−2) in our metagenome, and 1,172 of those were related to the DNA repair protein RadA. In this way, the microbial functional
profile of 0.2-μm-passable fraction in the present study differs from oceanic metagenomes in the 0.2-μm-trapped fractions
and hydrothermal vent metagenomes reported in previous research. 相似文献
7.
Weihua Yu Yan Zou Yingshi Du Jing Luo Man Zhang Wenxiu Yang Xuefeng Wang Yang Lü 《Neurochemical research》2014,39(11):2211-2217
Transforming growth factor beta (TGFβ) signaling participates in pathogenesis of epilepsy. TGFβ1, as a transmitter of TGFβ signaling, might be a useful marker for predicting the prognosis of patients with epilepsy. The present study aimed to measure TGFβ1 level in the cerebrospinal fluid (CSF) of patients with drug-resistant epilepsy and non-resistant epilepsy. A total of 43 patients with epilepsy were recruited, 28 were non-resistant epilepsy subgroup, 15 drug-resistant epilepsy subgroup. 11 patients with intracranial infection and 11 individuals with primary headache were used as controls. The concentration of CSF and serum TGFβ1 was measured by enzyme-linked immunosorbent assay. The concentration of CSF-TGFβ1 was 209.26 ± 81.07 pg/ml in the drug-resistant epilepsy subgroup, 121.80 ± 40.32 pg/ml in the non-resistant epilepsy subgroup, 552.17 ± 456.20 pg/ml in intracranial infection control, 133.80 ± 68.55 pg/ml in headache control, respectively. TGFβ1 level was significantly increased in the drug-resistant epilepsy subgroup compared to the non-resistant epilepsy subgroup. TGFβ1 level in intracranial infection control was higher than that in the non-resistant epilepsy subgroup. There was no statistically difference of CSF-TGFβ1 between the non-resistant epilepsy subgroup and headache controls, between the resistant epilepsy subgroup and intracranial infection controls. TGFβ levels are increased in the CSF of patients with drug-resistant epilepsy. High CSF-TGFβ1 levels may be a potential screening biomarker of antiepileptic drug resistance in patients with epilepsy. 相似文献
8.
Benjamin L. VaughanJr. Bryan G. Smith David L. Chopp 《Bulletin of mathematical biology》2010,72(5):1143-1165
In this paper, we study quorum sensing in Pseudomonas aeruginosa biofilms. Quorum sensing is a process where bacteria monitor their population density through the release of extra-cellular
signalling molecules. The presence of these molecules affects gene modulation leading to changes in behaviour such as the
release of virulence factors. Here, we use numerical methods to approximate a 2-D model of quorum sensing. It is observed
that the shape of the biofilm can have a profound effect on the onset of quorum sensing. This has serious repercussions for
experimental observations since biofilms of the same biomass but different shapes can produce quite different results. 相似文献
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Kenneth A. Mann Mark A. Miller 《Computer methods in biomechanics and biomedical engineering》2014,17(16):1809-1820
Experimental tests and computational modelling were used to explore the fluid dynamics at the trabeculae–cement interlock regions found in the tibial component of total knee replacements. A cement–bone construct of the proximal tibia was created to simulate the immediate post-operative condition. Gap distributions along nine trabeculae–cement regions ranged from 0 to 50.4 μm (mean = 12 μm). Micro-motions ranged from 0.56 to 4.7 μm with a 1 MPa compressive load to the cement. Fluid–structure analysis between the trabeculae and the cement used idealised models with parametric evaluation of loading direction, gap closing fraction (GCF), gap thickness, loading frequency and fluid viscosity. The highest fluid shear stresses (926 Pa) along the trabecular surface were found for conditions with very thin and large GCFs, much larger than reported physiological levels (~1–5 Pa). A second fluid–structure model was created with a provision for bone resorption using a constitutive model with resorption velocity proportional to fluid shear rate. A lower cut-off was used, below which bone resorption would not occur (50 s? 1). Results showed that there was initially high shear rates (>1000 s? 1) that diminished after initial trabecular resorption. Resorption continued in high shear rate regions, resulting in a final shape with bone left deep in the cement layer, and is consistent with morphology found in post-mortem retrievals. Small gaps between the trabecular surface and the cement in the immediate post-operative state produce fluid flow conditions that appear to be supra-physiologic; these may cause fluid-induced lysis of trabeculae in the micro-interlock regions. 相似文献
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Monge-Argilés JA Muñoz-Ruiz C Pampliega-Pérez A Gómez-López MJ Sánchez-Payá J Rodríguez Borja E Ruiz-Vegara M Montoya-Gutiérrez FJ Leiva-Santana C 《Neurochemical research》2011,36(6):986-993
The study of biomarkers in the cerebrospinal fluid (CSF) of patients with mild cognitive impairment (MCI) is a technique used
with increasing frequency in the early diagnosis of Alzheimers disease (AD). Our objectiv was to gain an own experience while
evaluating the reliability, sensitivity, and reproducibility of this technique in Spanish patients. Thirty-seven patients
with MCI and twenty-four control subjects were studied by means of AD biomarker analysis in CSF. xMAP Luminex and INNO-BIA
Alzbio3 reagents of Innogenetics were used. The study variables assessed were levels of Aβ1–42, T-tau and P-tau181p proteins as well as the ratios of T-tau/Aβ1–42 and P-tau181p/Aβ1–42. Samples from nineteen patients were examined twice. Intra-class correlation coefficients for the three biomarkers used showed
values higher than 0.95. We observed significant differences between the control group and the MCI groups. In the 6 months
following lumbar puncture (LP), eleven (29%) patients with MCI developed AD. These patients showed significant lower levels
in Aβ1–42 protein (276.35 ± 78 vs. 367.13 ± 123.49, P < 0.03) and higher ratios (T-tau/Aβ1–42 [0.38 ± 0.2 vs. 0.22 ± 0.14, P < 0.01] and P-tau181p/Aβ1–42 [0.27 ± 0.13 vs. 0.16 ± 0.1, P < 0.008]) to those in the same group who remained stable. We obtained similar results to those in the most recent reliable
literature with our ROC curves, especially with our P-tau181p values and T-tau/Aβ1–42 ratio in order to differentiate between control and AD groups. Our experience showed that the analysis of CSF-AD biomarkers
in patients with MCI is reliable, sensitive and reproducible. In our knowledge, this is the first experience in Spanish patients. 相似文献
11.
Madalina Maftei Franka Thurm Cathrin Schnack Hayrettin Tumani Markus Otto Thomas Elbert Iris-Tatjana Kolassa Michael Przybylski Marilena Manea Christine A. F. von Arnim 《PloS one》2013,8(7)
Recent studies have suggested a protective role of physiological β-amyloid autoantibodies (Aβ-autoantibodies) in Alzheimer’s disease (AD). However, the determination of both free and dissociated Aβ-autoantibodies in serum hitherto has yielded inconsistent results regarding their function and possible biomarker value. Here we report the application of a new sandwich enzyme-linked immunosorbent assay (ELISA) for the determination of antigen-bound Aβ-autoantibodies (intact Aβ-IgG immune complexes) in serum and cerebrospinal fluid (CSF) of a total number of 112 AD patients and age- and gender-matched control subjects. Both serum and CSF levels of Aβ-IgG immune complexes were found to be significantly higher in AD patients compared to control subjects. Moreover, the levels of Aβ-IgG complexes were negatively correlated with the cognitive status across the groups, increasing with declining cognitive test performance of the subjects. Our results suggest a contribution of IgG-type autoantibodies to Aβ clearance in vivo and an increased immune response in AD, which may be associated with deficient Aβ-IgG removal. These findings may contribute to elucidating the role of Aβ-autoantibodies in AD pathophysiology and their potential application in AD diagnosis. 相似文献
12.
N. Guerreiro B. Gomez-Mancilla B. Williamson M. Minkoff S. Guertin 《Clinical proteomics》2009,5(2):114-124
Introduction Alzheimer’s disease (AD) poses specific challenges for drug development. It has a slow and variable clinical course, an insidious
onset, and symptom expression is only observed when a significant proportion of neurons are already lost.
Discussion Determinants of clinical course, such as molecular biomarkers, are urgently needed for early detection and diagnosis, or for
prognosis and monitoring disease-modifying therapies in stratified patient populations. Due to its proximity to the brain
and clinical availability, cerebrospinal fluid (CSF) is likely to have the highest yield of biomarker potential for neurodegenerative
diseases. In this study, we examined the feasibility of using of an 8-plex isobaric tagging approach, coupled to two-dimensional
liquid chromatography and tandem mass spectrometry using the matrix-assisted laser desorption/ionization time-of-flight/time-of-flight
platform, for the discovery of potential biomarker candidates in CSF. Comparative analysis identified a number of statistically
significant differences in the level of proteins when comparing AD to nondemented controls. Although the study is statistically
underpowered to represent the disease population, the regulation of proteins with involvement in processes such as neuronal
loss, synaptic dysfunction, neuroinflammation, and tissue degeneration and remodeling reflects the ability of our method in
providing biologically meaningful CSF biomarkers as candidates for larger scale biomarker verification and validation studies. 相似文献
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This communication is pivoted to the sensing of fluids by the use of nanoengineered thin films comprised of copper nano-helixes as well as copper nano-rods, in order to study the comparison of the performance of thin films having different morphological features. For this purpose, human blood samples having different concentrations of haemoglobin are taken into account as measurands. The sensing configuration exploits the use of nanostructured metallic thin films grown over glass substrate with the void regions filled up with measurands, and the features of absorption spectra are monitored. Two different wavelengths are used along with two different values of helix pitch angle as well as slanting angle of nano-rods, and the focus is put on the effect due to these parameters on the sensing characteristics. It is observed that in the case of nano-helix structured films, pitch angle affects spectral characteristics obtained due to the generation of plasmonic waves at the interface of two partnering mediums. Upon comparing the obtained results with those corresponding to thin films comprised of slanted copper nano-rods (having different angles of inclination), it has been found that the nano-helix embedded films provide better appreciable results than those exhibited by the columnar thin films, thereby making the former kind of nanostructured mediums more useful in sensing-related applications. 相似文献
15.
K. Dumont J.M.A. Stijnen J. Vierendeels F.N. van de Vosse P.R. Verdonck 《Computer methods in biomechanics and biomedical engineering》2013,16(3):139-146
Simulations of coupled problems such as fluid–structure interaction (FSI) are becoming more and more important for engineering purposes. This is particularly true when modeling the aortic valve, where the FSI between the blood and the valve determines the valve movement and the valvular hemodynamics. Nevertheless only a few studies are focusing on the opening and closing behavior during the ejection phase (systole). In this paper, we present the validation of a FSI model using the dynamic mesh method of Fluent for the two-dimensional (2D) simulation of mechanical heart valves during the ejection phase of the cardiac cycle. The FSI model is successfully validated by comparing simulation results to experimental data obtained from in vitro studies using a CCD camera. 相似文献
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In cases in which there is massive loss of fluids or electrolytes or prolonged decreased urinary output, an absolutely accurate knowledge of all water and chloride intake and output by all routes is necessary to avert large and often fatal errors in water and electrolyte therapy based on estimates made from nurses'' notes alone.By use of the Scribner water-chloride balance sheet method of recording data, it is possible to determine with the necessary accuracy how much fluid and what kind of electrolytes to administer to achieve and maintain balance. The method is simple and can be put into effect in any hospital with the cooperation of an educated nursing and laboratory staff. 相似文献
18.
The effects of six different polyglycerol esters of fatty acids (PGEs) and two different particle sizes produced using various
processing parameters on the physicochemical properties and stability of the β-carotene emulsions during digestion in simulated
gastric fluid (SGF) were investigated. β-Carotene emulsions were prepared by high-pressure homogenization using β-carotene
(0.1% w/w) in soybean oil as the oil phase and 1% (w/w) PGE in Milli-Q water as the water phase. The particle size of β-carotene emulsions was measured by a laser diffraction technique,
and the stability of emulsions was interpreted in terms of the increase in particle size and span value of emulsion droplets
and the retention of β-carotene during digestion in SGF. The average particle size ranges of emulsions were 0.17 to 0.27 μm
for fine emulsions and 1.16 to 1.59 μm for coarse emulsions. In the prepared β-carotene emulsions, the particle size decreased
with increasing polymerization of the glycerol in PGEs, and the higher polymerization of the glycerol also increased the stability
of emulsions during digestion in SGF. Although the β-carotene content in the emulsions significantly decreased with increasing
digestion period, loss of β-carotene was more severe in unstable emulsions than in stable emulsions, suggesting that the particles
incorporated into droplets could provide some protective barrier for decreasing the β-carotene degradation. Therefore, β-carotene
emulsions stabilized by PGEs with high polymerization of the glycerol may be useful for further applications in food and drug
formulations. Decaglycerol monooleate (MO750) was demonstrated to be the most effective emulsifier in stabilizing β-carotene
emulsions in this study. 相似文献
19.
Akira Matsumoto Reiko Matsumoto Kei-ichi Kadoyama Taka-aki Nishimoto Shogo Matsuyama Osamu Midorikawa 《International journal of peptide research and therapeutics》2009,15(3):205-210
Establishment of diagnostic measures for early stage Alzheimer’s disease (AD) and mild cognitive impairment (MCI) is of crucial
importance. Using surface enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS), antibody-assisted
MS of cerebrospinal fluid (CSF) has enabled quantitative analysis of the ratio of β-amyloid (Aβ) peptides, Aβ1-42/Aβ1-40,
which has a diagnostic value for AD/MCI. To apply the MS analysis to a far wider range of CSF samples, we have established
a method to analyze Aβ peptides expressed in 100 μl CSF samples quantitatively. Pretreatment of CSF samples by limit-filtration
to condense peptides, and modified washing procedure using urea as denaturant, Aβ peptides of interest can be assessed with
higher sensitivity by five to tenfolds to the original method. This improvement enables quantitative analysis of Aβ species
from a residual amount of CSF samples, which will be occasionally obtained in case of lumbar anesthesia prior to operation
and spinal tap performed for routine diagnostic purposes. Prevalence of the new procedure as laboratory test, especially among
the elderly consulting for neurological clinic, will enhance the number of subjects diagnosed at early stage of AD/MCI. 相似文献
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Sabine Gollner Barbara Riemer Pedro Martínez Arbizu Nadine Le Bris Monika Bright 《PloS one》2010,5(8)