***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract — Flow-mediated dilatation ( FMD ) of conduit arteries is dependent on an intact endothelium , although the mechanisms are not fully understood . Using high-resolution ultrasound , we examined the role of endothelial mediators in radial artery dilatation in response to transient ( short period of reactive hyperemia ) and sustained ( prolonged period of reactive hyperemia , h and warming , or an incremental infusion of acetylcholine into the distal radial artery ) hyperemia . After short episodes of reactive hyperemia , FMD was abolished by local infusion of the nitric oxide synthesis inhibitor NGmonomethyl-l-arginine ( 5.3±1.2 % versus 0.7±0.7 % , P < 0.001 ) . In contrast , basal vessel diameter and dilatation after prolonged episodes of reactive hyperemia , h and warming , and distal infusion of acetylcholine were not attenuated by nitric oxide synthesis inhibition . Inhibition of cyclooxygenase or local autonomic nervous system blockade also had no effect on FMD .  Patients with hypercholesterolemia exhibited reduced FMD in response to transient hyperemia , but the response to sustained hyperemia was normal . These data suggest heterogeneity of endothelial responses to blood flow that are dependent on the characteristics of the flow stimulus . Dilatation after brief episodes of hyperemia is mediated by release of nitric oxide , whereas dilatation during sustained hyperemia is unaffected by NO synthesis inhibition . Hypercholesterolemia seems to differentially affect these pathways with impairment of the nitric oxide – dependent pathway and preservation of non nitric oxide – mediated dilatation to sustained flow stimuli Low-fat diets , in which carbohydrates replace some of the fat , decrease serum cholesterol . This decrease is due to decreases in LDL-cholesterol but in part to possibly harmful decreases in HDL-cholesterol . High-oil diets , in which oils rich in monounsaturated fat replace some of the saturated fat , decrease serum cholesterol mainly through LDL-cholesterol . We used these two diets to investigate whether a change in HDL-cholesterol would change flow-mediated vasodilation , a marker of endothelial function . We fed thirty-two healthy volunteers two controlled diets in a weeks ' r and omised cross-over design to eliminate variation in changes due to differences between subjects . The low-fat diet contained 59.7 % energy ( en% ) as carbohydrates and 25.7 en% as fat ( 7.8 en% as monounsaturates ) ; the oil-rich diet contained 37.8 en% as carbohydrates and 44.4 en% as fat ( 19.3 en% as monounsaturates ) . Average ( sd ) serum HDL-cholesterol after the low-fat diet was 0.21 ( sd 0.12 ) mmol/l ( 8.1 mg/dl ) lower than after the oil-rich diet .  Serum triacylglycerols were 0.22 ( sd 0.28 ) mmol/l ( 19.5 mg/dl ) higher after the low-fat diet than after the oil-rich diet .  Serum LDL and homocysteine concentrations remained stable . Flow-mediated vasodilation was 4.8 ( SD 2.9 ) after the low-fat diet and 4.1 ( SD 2.7 ) after the oil-rich diet ( difference 0.7 % ; 95 % CI -0.6 , 1.9 ) . Thus , although the low-fat diet produced a lower HDL-cholesterol than the high-oil diet , flow-mediated vasodilation , an early marker of cardiovascular disease , was not impaired Abstract Reliability refers to the reproducibility of values of a test , assay or other measurement in repeated trials on the same individuals . Better reliability implies better precision of single measurements and better tracking of changes in measurements in research or practical setting s. The main measures of reliability are within-subject r and om variation , systematic change in the mean , and retest correlation . A simple , adaptable form of within-subject variation is the typical ( st and ard ) error of measurement : the st and ard deviation of an individual ’s repeated measurements . For many measurements in sports medicine and science , the typical error is best expressed as a coefficient of variation ( percentage of the mean ) . A biased , more limited form of within-subject variation is the limits of agreement : the 95 % likely range of change of an individual ’s measurements between 2 trials . Systematic changes in the mean of a measure between consecutive trials represent such effects as learning , motivation or fatigue ; these changes need to be eliminated from estimates of within-subject variation . Retest correlation is difficult to interpret , mainly because its value is sensitive to the heterogeneity of the sample of participants . Uses of reliability include decision-making when monitoring individuals , comparison of tests or equipment , estimation of sample size in experiments and estimation of the magnitude of individual differences in the response to a treatment . Reasonable precision for estimates of reliability requires approximately 50 study participants and at least 3 trials . Studies aim ed at assessing variation in reliability between tests or equipment require complex design s and analyses that research ers seldom perform correctly . A wider underst and ing of reliability and adoption of the typical error as the st and ard measure of reliability would improve the assessment of tests and equipment in our disciplines Flow-mediated dilation ( FMD ) has been established as a reliable noninvasive measurement of endothelial function . The reproducibility of FMD under resting conditions has previously been reported ; however , the reproducibility of FMD in response to exercise remains to be investigated . On two separate days , we determined if flow-mediated dilation is reproducible in response to acute exercise in nine overweight men . Following pre-exercise FMD measurements , subjects were asked to walk on a treadmill for 45 min at 50 % of their VO(2)peak . Subsequently ,  FMD  was measured immediately , and every hour for 3 h thereafter . Reproducibility of FMD following exercise was assessed utilizing : ( 1 ) a two-way analysis of variance ( ANOVA ) , ( 2 ) Intraclass correlation coefficients ( ICC ) , ( 3 ) Pearson correlations ( r ) , and ( 4 ) coefficient of variation ( CV % ) and coefficient of variation prime ( CV ' ) for FMD at each time-period . Four acceptable reproducibility assessment s were required to confirm FMD reproducibility in response to acute exercise . No differences ( F(1,8 ) = .01 ; p = 0.942 ) in FMD were observed between trials collapsing for time . All the ICC(FMD ) fell within the reproducible criterion set and are as follows : pre-exercise 0.602 , immediately post 0.840 , 1 h post 0.632 , 2 h post 0.724 and 3 h post 0.631 . The correlation and the average CV% for FMD between trials was 0.579 % and 25.2 % , respectively . The FMD response to an acute bout of moderate treadmill exercise appears to be as reproducible as FMD measured during resting conditions . The findings of the present study support the use of FMD as an outcome variable in response to acute exercise Objective : To evaluate clinical ly a new on line , automated technique to measure flow mediated dilatation ( FMD ) as a marker of endothelial function . Design : Prospect i ve study . Patients : 12 healthy volunteers and 12 patients with significant , angiographically documented coronary artery disease . Interventions : Brachial arteries were imaged using a st and ard vascular ultrasound system with a 5–12 MHz linear transducer . Arterial diameter was measured on line ( in real time ) by connecting the ultrasound system to a personal computer equipped with a frame grabber and artery wall detection software ( VIA ) specially developed by the authors ’ group . By using this new technique , FMD was measured following 4.5 minutes of ischaemia of the proximal forearm in all subjects on two separate days . Results : The mean ( SD ) day to day variability in FMD measurements was 0.90 (0.48)%,which compares very favourably with current methods . The FMD measurement was available within seconds of completing the scan . Conclusions : Personal computer based automated techniques to assess FMD involve image acquisition and recording after which a second ( off line ) image interpretation session is required . The need for off line analysis makes current methods time consuming and increases the variability of measurement . This on line , automated analysis technique for FMD assessment reduces the variability and greatly increases the speed of measurement . Using this system may mean that fewer patients will be required in clinical trials assessing the effects of interventions on endothelial function . Adopting this method may also facilitate the screening of larger numbers of subjects for endothelial dysfunction To capture the response of an acute intervention , multiple post intervention measurements of flow-mediated dilation ( FMD ) must be performed . The effect of repetitive reactive hyperemia on endothelial function and the measurement of FMD are unknown . The purpose of this investigation was ( 1 ) to examine the effect of repetitive reactive hyperemia on brachial artery FMD and ( 2 ) to determine whether brachial artery FMD is stable during a 2-h morning period . We investigated FMD in 20 apparently healthy college students on three r and omized treatment days every 30 min ( T30 ) , 60 min ( T60 ) , and 120 min ( T120 ) throughout a 2-h morning period ( 08.00 h to 10.00 h ) . An ANOVA ( p > 0.05 ) and ICC ( > 0.40 ) were both needed to confirm no difference among repetitive reactive hyperemia treatments . In response to repetitive reactive hyperemia , there was no difference ( p = 0.307 ; ICC > 0.40 ) within the first and last FMD measurements of each treatment condition or between treatment conditions ( p = 0.344 ; ICC > 0.40 ) . FMD was similar ( p = 0.348 ) throughout the 2-h morning period . In conclusion , repetitive reactive hyperemia over a 2-h period has no effect on FMD measurements in apparently healthy college students . In addition , this study found no time trends for FMD measurements during the 2-h morning period to allow for pre/post intervention FMD measurements Flow-mediated vasodilation ( FMD ) in the brachial artery measured by ultrasound , and the increase in forearm blood flow ( FBF ) induced by local infusion of a muscarinic-receptor agonist have both frequently been used to evaluate endothelium-dependent vasodilation ( EDV ) in the human forearm . The present study intended to evaluate the relationship between these techniques and to investigate if vasodilation induced by the muscarinic receptor-agonist methacholine ( MCh ) was owing to production of nitric oxide ( NO ) . FMD during hyperaemia was assessed by ultrasound and FBF was measured by venous occlusion plethysmography during local infusion of MCh or L-arginine in the human forearm . Both these methods were applied in 26 individuals . In another 12 individuals forearm arterial and venous plasma concentrations of nitrate/nitrite ( NOx ) were measured together with FBF before and during local MCh infusion . While the change in brachial artery diameter induced by sublingually given nitroglycerine and the vasodilatory response to sodium nitroprusside ( SNP ) given locally in the forearm were significantly correlated ( r = 0.70 , P < 0.01 ) , FMD showed no relationship with the vasodilation evoked by MCh ( r = -0.03 ) or L-arginine ( r = 0.04 ) . The five-fold increase in FBF during MCh infusion was associated with a significant increase in venous plasma NOx concentrations ( P < 0.05 ) and a more than 11-fold increase in forearm NOx-release ( P < 0.01 ) . Thus , a significant relationship between the two methods regarding the evaluation of endothelium-independent vasodilation evoked by NO-donors was found , but no relationship was found between the two methods regarding the evaluation of endothelium-dependent vasodilation . Furthermore , vasodilation induced by MCh in the forearm seems to be induced by NO-release 
    Output:
    
These data demonstrate that adherence to current expert consensus guidelines and applying contemporary techniques for measuring brachial artery FMD decreases its measurement error