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21.
We evaluated the IL Monarch random-access centrifugal analyzer for measurement of Na+, K+, and Cl- by an indirect potentiometric method. For different concentrations of control material, the total precision (CV) ranged between 0.82% and 1.14% for the three electrolytes; linearity was acceptable within a range of 103 to 215 mmol/L for Na+, 1.6-15.25 mmol/L for K+, and 80-173 mmol/L for Cl-. Data correlated well with those by flame photometry for Na+ and K+ and with those by coulometry for Cl-, both for various biological materials--sera, urines, dialysis fluids--and commercial control materials from various producers. Stability of the potentiometric signal was acceptable: daily variations were 0.2 mV for Na+, 0.05 mV for K+, and 0.03 mV for Cl-. Accordingly, we conclude that the system supplies reproducible and accurate results while being easy to use and requiring little maintenance. The use of indirect potentiometry offers results consistent with those obtained with traditional methods, and easily interpretable by clinical staff. However, better information about the actual ion activity in the tested sample for certain pathologies such as hyperlipemia and dysproteinemia could be obtained by methods involving direct potentiometry. 相似文献
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Interaction of Dr adhesin with collagen type IV is a critical step in Escherichia coli renal persistence 下载免费PDF全文
Selvarangan R Goluszko P Singhal J Carnoy C Moseley S Hudson B Nowicki S Nowicki B 《Infection and immunity》2004,72(8):4827-4835
The pathogenic mechanism of recurrent or chronic urinary tract infection is poorly understood. Escherichia coli cells bearing Dr fimbriae display unique tropism to the basement membrane (BM)-renal interstitium that enables the bacteria to cause chronic pyelonephritis in experimental mice. The renal receptors for Dr-fimbriated E. coli are type IV collagen and decay-accelerating factor (DAF). We hypothesized that type IV collagen receptor-mediated BM-interstitial tropism is essential for E. coli to cause chronic pyelonephritis. To test the role of the type IV collagen tropism of Dr-fimbriated E. coli in renal persistence, we constructed an isogenic mutant in the DraE adhesin subunit that was unable to bind type IV collagen but retained binding to DAF and examined its virulence in the mouse model. The collagen-binding mutant DrI113T was eliminated from the mouse renal tissues in 6 to 8 weeks, while the parent strain caused persistent renal infection that lasted at least 14 weeks (P < or = 0.02). Transcomplementation with the intact Dr operon restored collagen-binding activity, BM-interstitial tropism, and the ability to cause persistent renal infection. We conclude that type IV collagen binding mediated by DraE adhesin is a critical step for the development of persistent renal infection in a murine model of E. coli pyelonephritis. 相似文献
24.
The interaction of normal lymphocytes and cells from lymphoid cell lines: II. Variations relating to cell line source and lymphocyte donor 下载免费PDF全文
Irradiated LCL cells from several sources activated the blood lymphocytes of a panel of donors. Individual differences were present but were small. Stimulated blood lymphocytes were more potent activators (after X-irradiation) than small lymphocytes in a one-way mixed lymphocyte reaction, indicating that the state of metabolic activity of the `stimulating' lymphocyte affects the level of activation achieved. However, LCL cells incubated for several days after irradiation had not lost stimulatory capacity. Lymphocytes of pigs, rabbits, rats and mice were much less responsive than human lymphocytes. The response of animal lymphocytes generally varied with the species of origin of the serum used in the cultures. 相似文献
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The effect of surface chemistry modification of titanium alloy on signalling pathways in human osteoblasts 总被引:2,自引:0,他引:2
Zreiqat H Valenzuela SM Nissan BB Roest R Knabe C Radlanski RJ Renz H Evans PJ 《Biomaterials》2005,26(36):7579-7586
Establishing and maintaining mature bone at the bone–device interface is critical to the long-term success of prosthesis. Poor cell adhesion to orthopaedic and dental implants results in implant failure. Considerable effort has been devoted to alter the surface characteristics of these biomaterials in order to improve the initial interlocking of the device and skeleton. We investigated the effect of surface chemistry modification of titanium alloy (Ti–6Al–4V) with zinc, magnesium or alkoxide-derived hydroxy carbonate apatite (CHAP) on the regulation of key intracellular signalling proteins in human bone-derived cells (HBDC) cultured on these modified Ti–6Al–4V surfaces. Western blotting demonstrated that modifying Ti–6Al–4V with CHAP or Mg results in modulation of key intracellular signalling proteins. We showed an enhanced activation of Shc, a common point of integration between integrins and the Ras/Mapkinase pathway. Mapkinase pathway was also upregulated, suggesting its role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the Mg and CHAP modified Ti–6Al–4V. Thus surface modification with CHAP or Mg may contribute to successful osteoblast function and differentiation at the skeletal tissue–device interface. 相似文献
27.
Cells are known to be surrounded by nanoscale topography in their natural extracellular environment. The cell behavior, including morphology, proliferation, and motility of bovine pulmonary artery smooth muscle cells (SMC) were studied on poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) surfaces comprising nanopatterned gratings with 350 nm linewidth, 700 nm pitch, and 350 nm depth. More than 90% of the cells aligned to the gratings, and were significantly elongated compared to the SMC cultured on non-patterned surfaces. The nuclei were also elongated and aligned. Proliferation of the cells was significantly reduced on the nanopatterned surfaces. The polarization of microtubule organizing centers (MTOC), which are associated with cell migration, of SMC cultured on nanopatterned surfaces showed a preference towards the axis of cell alignment in an in vitro wound healing assay. In contrast, the MTOC of SMC on non-patterned surfaces preferentially polarized towards the wound edge. It is proposed that this nanoimprinting technology will provide a valuable platform for studies in cell-substrate interactions and for development of medical devices with nanoscale features. 相似文献
28.
Presynaptic inhibition is a major mechanism for regulating synaptic transmission in the CNS and adenosine inhibits Ca(2+) currents (I(Ca)) to reduce transmitter release at several synapses. Rod photoreceptors possess L-type Ca(2+) channels that regulate the release of L-glutamate. In the retina, adenosine is released in the dark when L-glutamate release is maximal. We tested whether adenosine inhibits I(Ca) and intracellular Ca(2+) increases in rod photoreceptors in retinal slice and isolated cell preparations. Adenosine inhibited both I(Ca) and the [Ca(2+)]i increase evoked by depolarization in a dose-dependent manner with approximately 25% inhibition at 50 microM. An A2-selective agonist, (N(6)-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)-ethyl]adenosine) (DPMA), but not the A1- or A3-selective agonists, (R)-N(6)-(1-methyl-2-phenylethyl)adenosine and N(6)-2-(4-aminophenyl)ethyladenosine, also inhibited I(Ca) and depolarization-induced [Ca(2+)]i increases. An inhibitor of protein kinase A (PKA), Rp-cAMPS, blocked the effects of DPMA on both I(Ca) and the depolarization-evoked [Ca(2+)]i increase in rods. The results suggest that activation of A2 receptors stimulates PKA to inhibit L-type Ca(2+) channels in rods resulting in a decreased Ca(2+) influx that should suppress glutamate release. 相似文献
29.
Papillary carcinoma of the thyroid: hepatocyte growth factor (HGF) stimulates tumor cells to release chemokines active in recruiting dendritic cells 总被引:8,自引:0,他引:8 下载免费PDF全文
Scarpino S Stoppacciaro A Ballerini F Marchesi M Prat M Stella MC Sozzani S Allavena P Mantovani A Ruco LP 《The American journal of pathology》2000,156(3):831-837
Tissue distribution of dendritic cells was investigated in eight cases of papillary carcinoma of the thyroid using immunohistochemistry. Most dendritic cells had an immature phenotype (CD1a++, CD11c+, CD40+, CD86-, HLA-DR-) and were located at the invasion edge of the tumor. This pattern of distribution was profoundly different from that of CD68+ macrophages, which were evenly distributed throughout the tumor. The ability of tumor cells to release chemotactic factors active on dendritic cells was investigated in primary cultures of the same cases of papillary carcinoma, and was compared to that of the corresponding normal thyroid cells obtained from the tumor-free contralateral lobe. Chemotactic activity of culture supernatants was tested against dendritic cells in a chemotaxis chamber. It was found that papillary carcinoma cells were active in releasing chemotactic activity, that hepatocyte growth factor (HGF; 100 ng/ml) or interleukin (IL)-1beta (10(3) U/ml) induced a fourfold increase in the amount of chemotactic activity released, and that normal thyroid cells obtained from the same patients were as effective as tumor cells. Characterization of chemokines at RNA level revealed that unstimulated cells contain large amounts of IL-8 and monocyte chemotactic protein (MCP)-1 RNAs, and that stimulation with HGF or IL-1beta induced RNAs for regulated upon activation normal T expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-3alpha, interferon-gamma-inducible protein 10 (IP-10), and, to a lesser extent, MIP-1alpha and MIP-1beta. The possibility that HGF/Met interaction has a biological role in vivo was investigated in serial sections of six tumors immunostained for CD1a+, Met protein, and HGF. It was found that all six tumors were intensely and diffusely positive for Met protein, that HGF staining was present in tumor cells of the advancing edge, and that HGF+/Met+ tumor cell nests were infiltrated by CD1a+ dendritic cells. The foregoing observations are consistent with the possibility that HGF stimulation of Met+ tumor cells is one of the molecular mechanisms involved in the recruitment of dendritic cells. 相似文献
30.
The in vitro transformation of thymocytes and lymphocytes from humans, rabbits and guinea-pigs and from thymomas 总被引:1,自引:5,他引:1 下载免费PDF全文
Stella Knight J. Bradley J. J. Oppenheim N. R. Ling 《Clinical and experimental immunology》1968,3(4):323-341
The response of human, rabbit and guinea-pig thymocytes in culture to blastogenic stimulants such as phytohaemagglutinin (PHA) and staphylococcal filtrate (SF) was usually considerably less than that seen with equivalent numbers of peripheral blood and lymph node lymphocytes. 相似文献