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221.
Eva Hell Christian G. Giske Kjell Hultenby Kristina Gemzell Danielsson Giovanna Marchini 《Current microbiology》2013,67(6):712-717
Staphylococcus epidermidis, a human commensal, is an important opportunistic, biofilm-forming pathogen and the main cause of late onset sepsis in preterm infants, worldwide. In this study we describe the characteristics of S. epidermidis strains causing late onset (>72 h) bloodstream infection in preterm infants and skin isolates from healthy newborns. Attachment and biofilm formation capability were analyzed in microtiter plates and with transmission electron microscopy (TEM). Clonal relationship among strains was studied with pulsed-field gel electrophoresis. Antimicrobial susceptibility testing was performed, as well as the detection of biofilm-associated genes and of the invasiveness marker IS256 with polymerase chain reaction. Blood and skin isolates had similar attachment and biofilm-forming capabilities and biofilm formation was not related to the presence of specific genes. Filament-like membrane structures were seen by TEM early in the attachment close to the device surface, both in blood and skin strains. Nine of the ten blood isolates contained the IS256 and were also resistant to methicillin and gentamicin in contrast to skin strains. S. epidermidis strains causing bloodstream infection in preterm infants exhibit higher antibiotic resistance and are provided with an invasive genetic equipment compared to skin commensal strains. Adhesion capability to a device surface seems to involve bacterial membrane filaments. 相似文献
222.
Jin Zhang Dou Yin Fang Wu Gongliang Zhang Chuanwei Jiang Zhen Li Liecheng Wang Kai Wang 《Neurochemical research》2013,38(8):1616-1623
Adenosine (AD) is a nucleic acid component that is critical for energy metabolism in the body. AD modulates numerous neural functions in the central nervous system, including the sleep-wake cycle. Previous studies have indicated that the A1 receptor (A1R) or A2A receptor (A2AR) may mediate the effects of AD on the sleep-wake cycle. The hypothalamic ventrolateral preoptic area (VLPO) initiates and maintains normal sleep. Histological studies have shown A1R are widely expressed in brain tissue, whereas A2AR expression is limited in the brain and undetectable in the VLPO. We hypothesize therefore, that AD modulates the sleep-wake cycle through A1R in the VLPO. In the present study, bilateral microinjection of AD or an AD transporter inhibitor (s-(4-nitrobenzyl)-6-thioinosine) into the VLPO of rats decreased non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. An A1R agonist (N6-cyclohexyladenosine) produced similar effects in the VLPO. Microinjection of an A1R antagonist (8-cyclopentyl-1,3-dimethylxanthine) into the VLPO enhanced NREM sleep and diminished AD-induced wakefulness. These data indicate that AD enhances wakefulness in the VLPO via A1R in rats. 相似文献
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Wanju Zhang Kai Zhang Xujie Xiong 《Journal of biomolecular structure & dynamics》2013,31(16):4251-4257
Communicated by Ramaswamy H. Sarma 相似文献
227.
Roger Persson Anne Helene Garde Åse Marie Hansen Kai Österberg Britt Larsson Palle Ørbæk 《Chronobiology international》2013,30(6):923-937
Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month‐to‐month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time‐of‐day (4 levels) as categorical predictors. Cortisol concentrations were analyzed on a log scale. The diurnal pattern of cortisol was similar across months (interaction between month and time of day: p>0.4). The main effects of month and time‐of‐day were statistically significant (p <0.001). Highest concentrations were observed in February, March, and April, and lowest concentrations were observed in July and August. There were no statistically significant effects in any of the other measures, or between men and women. In conclusion, a seasonal variation in salivary cortisol concentrations was detected in an occupationally active population. Thus, seasonal variation needs to be taken into account when designing and evaluating field studies and interventions and when making comparisons across studies. 相似文献
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