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81.
Biomaterials-centered infections are serious complications associated with the use of implants. The infection risk of biomaterials varies between different materials and is determined by the chemical composition of materials, the host proteins and the type of bacteria. In this study we measured the initial adhesion of Staphylococcus aureus onto polystyrene derivatives containing carboxylate and sulfonate groups. Five polymers were synthesized and characterized. We studied the role of the host protein fibronectin in promoting adhesion of Staphylococcus aureus. Fibronectin adsorption was comparable on all the tested polymers (pKd=7.2±0.2) whereas bacterial adhesion was dependent on surfaces chemical compositions. Polymers substituted with sulfonate groups showed the most important inhibition of initial bacterial adhesion. 相似文献
82.
Y.-P. LOU A. FRANCO-CERECEDA J. M. LUNDBERG 《Acta physiologica (Oxford, England)》1992,146(1):119-127
Vagal nerve stimulation (1 Hz for 1 min), capsaicin (10-8 M and 10-6 M), resiniferatoxin (3 × 10-10 M) and nicotine (10-4 M) evoked a non-cholinergic bronchoconstriction in the isolated perfused guinea-pig lung preparation. Simultaneously there was an increase in the perfusate levels of calcitonin gene-related peptide-like immunoreactivity, suggesting release from sensory nerves. Both the bronchoconstriction and peptide release evoked by a low concentration of capsaicin (10-8 M) and that evoked by nerve stimulation were depressed by tetrodotoxin, suggesting involvement of Na+ channel dependent depolarization. Since the effects of capsaicin (10-8 M) and vagal nerve stimulation were inhibited by ω-conotoxin but not influenced by nifedipine, the Ca2+-channel involved is probably of N-type. Furthermore, the capsaicin analogue resiniferatoxin also evoked ω-conotoxin sensitive peptide release and bronchoconstriction. At the higher capsaicin concentration (10-6 M), the functional response was only slightly inhibited by wconotoxin or tetrodotoxin indicating that capsaicin at this concentration evoked peptide release and functional effects through other mechanisms, probably involving Ca2+ fluxes in the non-selective cation channel associated with the proposed capsaicin receptor. The nicotine (10-4 M) evoked peptide release and bronchoconstriction were only marginally influenced by ω-conotoxin or tetrodotoxin. It is concluded that the ion-channel mechanisms underlying the peptide releasing properties of antidromic nerve stimulation and low concentrations of capsaicin are similar and depend on action potential propagation, whereas capsaicin in high, toxic concentration and nicotine mainly act via receptor operated channels. 相似文献
83.
84.
Suga S Nakano K Takeo T Osanai T Ogawa Y Yagihashi S Kanno T Wakui M 《Pflügers Archiv : European journal of physiology》2003,447(3):337-344
The effect of noradrenaline (NE) on rat islet -cells was examined. NE reduced insulin secretion from rat islets exposed to extracellular solutions containing glucose at 5.5 or 16.6 mM. In islets treated with pertussis toxin (PTX), however, NE increased insulin secretion. The NE-induced augmentation of insulin secretion was inhibited by prazosin. In intact islets, NE increased phospholipase C (PLC) activity, an effect that was prevented by treatment of islets with U-73122. NE elevated intracellular [Ca2+] ([Ca2+]i) in isolated -cells independently of PTX. Although this NE effect was inhibited by prazosin, phenylephrine did not mimic it. The [Ca2+]i response to NE was also prevented by the treatment of cells with U-73122. NE produced depolarization of -cells followed by nifedipine-sensitive action potentials. NE reduced the whole-cell membrane currents through ATP-sensitive K+ channels (KATP), responsible for the depolarization. This NE effect was prevented by treatment of -cells with U-73122 or BAPTA/AM. Although at least some of our results imply the presence of 1-adrenoceptors, -cells were not stained by a polyclonal IgG antibody recognizing all adrenergic 1-receptor subtypes so far identified. These results suggest that an interaction of NE with an unknown type of receptor activates rat islet -cells via a PLC-dependent signal pathway. This effect is, however, masked by the inhibitory action via a PTX-sensitive pathway also activated by NE. 相似文献
85.
Jacques C. Giltay Klasien B. J. Gerssen-Schoorl Ab van der Wagen 《Clinical genetics》1994,46(3):271-272
The present paper describes a girl with a small de novo deletion of chromosome 9(p12p13). This deletion has not been published previously. The deleted fragment is clearly outside the region involved in the so-called deletion 9p syndrome. The patient had mild dysmorphic features and feeding problems during the first weeks of life, but is now developing well. Because of the lack of severe clinical features in this patient, we speculate that the deletion may be prevalent in other patients who have no clinical indication for chromosome investigation. 相似文献
86.
目的研究新发现的人内源性逆转录病毒 NP9基因在系统性红斑狼疮(systemic lupus erythematosus, SLE)患者体内表达及其蛋白功能预测.方法逆转录PCR、T-A克隆技术和DNA序列测定分离、克隆和分析 NP9基因, 检测40例SLE患者和48名正常对照的 NP9基因表达, 借助NCBI BLAST系列分析工具及相应的基因分析软件预测其蛋白功能.结果 SLE患者组逆转录病毒 NP9基因表达阳性率为77.5%(31/40),明显高于正常对照的8.3%(4/48), P<0.01. NP9基因编码产物由74个氨基酸组成,含有多个细胞核内分布信号,其等电点(pI)为9.59,与SLE患者体内高表达的某些细胞因子具有较高同源性.结论 SLE患者存在逆转录病毒 NP9基因特异性转录, NP9表达可能与SLE发生发展相关. 相似文献
87.
88.
Expression of MMP2, MMP9 and MMP3 in Breast Cancer Brain Metastasis in a Rat Model 总被引:11,自引:0,他引:11
In order to study the expression of MMP2, MMP3 and MMP9 in breast cancer brain metastasis, we used a syngeneic rat model of
distant metastasis of ENU1564, a carcinogen-induced mammary adenocarcinoma cell line. At six weeks post inoculation we observed
development of micro-metastasis in the brain. Immunohistochemistry and Western Blotting analyses showed that MMP-2, -3 and
-9 proteins expressions are consistently significantly higher in neoplastic brain tissue compared to normal brain tissue.
These results were confirmed by RT-PCR. In situ zymography revealed gelatinase activity within the brain metastasis. Gel zymography showed increase in MMP2 and MMP3 activity
in brain metastasis. Furthermore, we were able to significantly decrease the development of breast cancer brain metastasis
in animals by treatment with PD 166793, a selective synthetic MMP inhibitor. In addition, PD 166793 decreased the in vitro invasive cell behavior of ENU1546. Together our results suggest that MMP-2, -3 and -9 may be involved in the process of metastasis
of breast cancer to the brain. 相似文献
89.
90.
We investigated the oxygen uptake (O2) response to exhaustive square wave exercise of approximately 2, 5 and 8 min duration in cycling and running. Nine males completed a ramp test and three square wave tests on a motorised treadmill and the same four tests on a cycle ergometer, throughout which gas exchange was assessed (Douglas bag method). The peak O2 from the ramp test was higher for running than for cycling [mean (SD): 58.4 (2.8) vs. 55.9 (3.7) ml.kg–1.min–1; P=0.04]. However O2max (defined as the highest O2 achieved in any of the four tests) did not differ between running and cycling [60.0 (2.9) vs. 58.5 (3.3) ml.kg–1.min–1; P=0.15]. The peak O2 was similar (P>0.1) for the 5 and 8 min square wave tests [98.5 (1.8) and 99.2 (2.3) %O2max for running; 97.0 (4.2) and 97.5 (2.0) %O2max for cycling] but lower (P<0.001) for the 2-min test [91.8 (2.5) and 89.9 (5.5) %O2max for running and cycling respectively]. O2 increased over the final two 30-s collection periods of the 2-min test for cycling [O2=0.18 (0.15) l.min–1; P<0.01] but not running [O2=0.00 (0.09) l.min–1; P=0.98]. We conclude that in the aerobically fit the peak O2 for square wave running or cycling at an intensity severe enough to result in exhaustion in approximately 2 min is below O2max. In running, O2 plateaus at this sub-maximal rate. 相似文献