首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 187 毫秒
1.
BackgroundVaccines may reduce antibiotic use and the development of resistance.ObjectivesTo provide a comprehensive, up-to-date assessment of the evidence base relating to the effect of vaccines on antibiotic use.Data sourcesOvid MEDLINE, Embase, the Cochrane Library, ClinicalTrials.gov and WHO Trials Registry.Study eligibility criteriaRandomized controlled trials (RCTs) and observational studies published from January 1998 to March 2018.ParticipantsAny population.InterventionsVaccines versus placebo, no vaccine or another vaccine.MethodsTitles, abstracts and full-texts were screened independently by two reviewers. Certainty of RCT evidence was assessed using GRADE.ResultsIn all, 4980 records identified; 895 full-text reports assessed; 96 studies included (24 RCTs, 72 observational). There was high-certainty evidence that influenza vaccine reduces days of antibiotic use among healthy adults (one RCT; n = 4253; rate reduction 28·1%; 95% CI 16·0–38·4); moderate-certainty evidence that influenza vaccines probably reduce antibiotic use in children aged 6 months to 14 years (three RCTs; n = 610; ratio of means 0·62; 95% CI 0·54–0·70) and probably reduce community antibiotic use in children aged 3–15 years (one RCT; n = 10 985 person-seasons; risk ratio 0·69, 95% CI 0·58–0·83); and moderate-certainty evidence that pneumococcal vaccination probably reduces antibiotic use in children aged 6 weeks to 6 years (two RCTs; n = 47 945; rate ratio 0·93, 95% CI 0·87–0·99) and reduces illness episodes requiring antibiotics in children aged 12–35 months (one RCT; n = 264; rate ratio 0·85, 95% CI 0·75–0·97). Other RCT evidence was of low or very low certainty, and observational evidence was affected by confounding.ConclusionsThe evidence base is poor. Although some vaccines may reduce antibiotic use, collection of high-quality data in future vaccine trials is needed to improve the evidence base.PROSPERO registrationCRD42018103881.  相似文献   

2.
The performance of different signal processors for laser Doppler tissue flowmeters was evaluated by the use of a well defined flow model comprising a segment of the feline intestinal wall. The processor that, apart from being based on the calculation of the first moment of the power spectral density, also takes into account the effect of multiple scattering in a number of blood cells gave an output signal that was linearly related to the intestinal wall perfusion as recorded independently by a drop-counting technique. At a recording bandwidth of 12 kHz, this linear relationship was valid for the entire flow range 0–300 ml min−1 100 g−1 (r=0·98). The processor based on the first moment of the power spectral density alone under-estimated the highest flow rates by about 35 per cent, while within the flow range 0–100 ml min−1 100 g−1 this processor also gave an output signal linearly related to flow at a recording bandwidth of 12 kHz (r=0·96). When the bandwidth was limited to 4 kHz, the output signals from both processors were linearly related to flow only within the range 0–100 ml min−1 100 g−1 (r=0·90). The output signals recorded with the 4 kHz systems were, however, generally only about 65 per cent of those recorded with the 12 kHz systems.  相似文献   

3.
4.
In vivo tests were performed on a pH monitoring system. For this purpose 12 catheters were introduced into the arterial bloodstream of dogs. In the tip of the catheters (6F) a pH-sensitive ISFET sensor and an Ag/AgCl reference electrode were incorporated. Blood pH was varied by ventilation changes and injection of acidic and basic solutions into the animal’s blood. After stabilisation and in vivo calibration the output of the microprocessor-controlled pH monitor was compared with that of an in vitro pH/blood-gas analyser. The average deviation of the monitor output was 0·016 pH over a measurement period of 4 h. The maximum deviation observed was 0·06 pH. The system’s response is fast enough for monitoring changes in blood pH in clinical conditions.  相似文献   

5.
This paper describes techniques for the fabrication of flexible microelectrodes for recording and stimulation within the human body. The intention of the effort was to develop a prototype microelectrode array for selective electrical stimulation of the cochlear nerve in cases of profound sensory deafness. The prototype array is formed on both sides of a thin-film plastic insulating substrate? and consists of platinum conductor-elements, 0·3 μm thick and 12·7 μm wide, terminating at electrode surfaces, 250 μm wide. Metallisation of the substrate is accomplished by sputtering, and the electrode patterns are defined by photolithographic-etching techniques. Insulation of the array is achieved by dip coating in Silastic. Short term (nonstimulated) animal-tolerance studies indicate that the electrodes are biologically inert. Long-term implant studies are currently in progress, and experiments are planned to determine tissue-reaction and electrolytic-dissolution effects due to prolonged electrical stimulation. Microelectrodes using the fabrication techniques described can be applied, in practically any geometry desired, to the development of functional sensory and motor prostheses.  相似文献   

6.
A temperature regulator is described which is used in conjunction with a commercial electronic thermometer. Electrical transients are eliminated through the use of a battery-powered d.c. proportional controller. The result is an accurate, inexpensive laboratory instrument which can be used to maintain eitherin vivo orin vitro preparations within 0·2 C of desired temperature.  相似文献   

7.
A miniaturepH glass electrode for possible clinical and biomedical applications was constructed and evaluated in referencepH buffer solutions at 36°C. A field-effect-transistor (f.e.t.) amplifier was integrated into the system, and its effectiveness was investigated. The average e.m.f. efficiency of the developed electrode was 0·87±0·11V, and a minimum length of 7 mm was required for a goodpH response. Temperature dependence of the electrode was ?1·51 mV/oK at apH of 7. Evaluation of the stability of the electrode showed a 1% drift over a 7 h operational time. ThepH and temperature hysteresis effects showed 0·5% and 1·0% deviations, respectively. The response time was within 4 s for 99% response. These electrode characteristics were also investigated in blood plasma and discussed.  相似文献   

8.
A catheter-tip pH sensor was developed for possible clinical and biomedical application, using an ion-sensitive field-effect transistor (i.s.f.e.t.). Its signal drift in buffer solutions during continuous measurement was less than 3 mV in 24 h (equivalent to about 0·05 pH in 24 h). The electric insulation was perfect when soaked in buffer solutions for more than 3 months. A continuousin vivo pH measurement was successfully achieved in nonheparinised arterial blood of a japanese monkey. There was no significant sign of clot formation for 8 hours. It revealed quick responses to respiratory acidosis and alkalosis, and the observed pH values were in accordance with those confirmed by a blood pH analyser. Also, a catheter-tip pCO2 sensor was prepared, using the catheter-tip pH i.s.f.e.t. The response time was 2 min for a 90% change in CO2 tension. The muscle pCO2 monitoring tested with it indicated a similar result to those with medical mass spectrometer.  相似文献   

9.
Macrophages are involved in the development and progression of kidney fibrosis. The aim of this study was to analyse the phenotype of circulating monocytes and their ability to predict kidney allograft dysfunction in living kidney transplant recipients. Whole blood samples from 25 kidney recipients and 17 donors were collected at five time‐points. Monocyte phenotype was analysed by flow cytometry, and interleukin (IL)‐10 and soluble CD163 by enzyme‐linked immunosorbent assay. One week after transplantation, surface CD163 and IL‐10 levels increased significantly from baseline [2·99 ± 1·38 mean fluorescence intensity (MFI) to 5·18 ± 2·42 MFI for CD163; 4·5 ± 1·46 pg/ml to 6·7 ± 2·5 pg/ml for IL‐10]. This CD163 increase correlated with 4‐month creatinine levels (r = 0·4394, P = 0·04). However, soluble CD163 decreased significantly from baseline at 1 week (797·11 ± 340·45 ng/ml to 576·50 ± 293·60 ng/ml). CD14+CD16 monocytes increased at 4 months and correlated positively with creatinine levels at 12 and 24 months (r = 0·6348, P = 0·002 and r = 0·467, P = 0·028, respectively) and negatively with Modification of Diet in Renal Disease (MDRD) at 12 months (r = 0·6056, P = 0·003). At 4 months, IL‐10 decreased significantly (P = 0·008) and correlated positively with creatinine at 2 years (r = 0·68, P = 0·010) and with CD14+CD16 monocytes at 4 months (r = 0·732, P = 0·004). At 24 h, levels of human leucocyte antigen D‐related declined from 12·12 ± 5·99 to 5·21 ± 3·84 and CD86 expression decreased from 2·76 ± 1·08 to 1·87 ± 0·95. Both markers recovered progressively until 12 months, when they decreased again. These results indicate that monitoring monocytes could be a promising new prognostic tool of graft dysfunction in renal transplant patients.  相似文献   

10.
Direct measurement of the in vivo contractile properties of an individual muscle cannot be made in humans. The objective of this study was to predict the force–velocity (F–V) properties of slow human skeletal muscle for the in vivo temperature of 37 °C from F–V measurements in type I myofibers. Specifically, to quantitatively link myofiber measurements, which must be conducted at relatively low temperatures, to in vivo properties, the temperature-dependence of contractile properties must be modeled. We estimated the kinetic parameters of a crossbridge model within 15–30 °C from F–V measurements recorded in the myofibers of one subject, extrapolated their values at 37 °C, and then predicted the in vivo shortening and lengthening F–V curves. The prediction for maximal shortening velocity was 2.2 ± 0.2 fiber lengths per second and that for saturation force during lengthening was 2.3 ± 0.2 times isometric force. These estimates agree with previously reported in vivo measurements but are substantially different than those used in muscle models for many musculoskeletal simulations. The results from this study indicate that during low levels of muscle activation when slow motor units are primarily recruited, musculoskeletal models should consider having F–V properties that reflect the contractile properties of type I myofibers.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号