***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: Blood pressure reactivity is enhanced in young black subjects through mechanisms that are poorly understood . We compared & agr;-adrenergic – mediated vasoconstrictor and & bgr;-adrenergic vasodilator sensitivity and their relation to sympathetic activity in blacks and whites . Ten healthy black ( age , 29.9±2.4 years ) and 10 white ( age , 28.3±1.9 years ) men were studied . Forearm blood flow was measured with strain-gauge plethysmography after the intrabrachial artery administration of phenylephrine ( 1.25 to 20 & mgr;g/min ) and isoproterenol ( 60 and 400 ng/min ) after application of lower-body negative pressure and after a cold pressor test . Forearm and systemic norepinephrine spillover were measured with a radioisotope dilution technique . & agr;-Adrenergic vasoconstriction was markedly increased ( ANOVA P = 0.008 ) and & bgr;-adrenergic vasodilation decreased ( ANOVA P = 0.02 ) in blacks . Phenylephrine ( 10 & mgr;g/min ) decreased forearm blood flow by 58.0±2.5 % in blacks but only by 26.6±6.0 % in whites ( P < 0.001 ) . Vasoconstrictor response to endogenous norepinephrine , stimulated by a cold pressor test , result ed in a higher forearm vascular resistance in blacks than in whites ( 107.3±13 versus 64.8±13 mm Hg · mL−1 · 100 mL−1 , P = 0.03 ) . There were no significant ethnic differences in basal or stimulated forearm or systemic norepinephrine spillover . Increased vasoconstrictor and decreased vasodilator responses in blacks were not correlated . Increased sympathetically mediated vascular tone caused by enhanced vasoconstriction and attenuated vasodilation , effects that would be additive , and not increased sympathetic activity could enhance vascular reactivity and may play a role in the pathogenesis of hypertension in blacks Presentation , response to therapy , and clinical outcome in hypertension differ according to race , and these observations could relate to differences in microvascular function . We examined forearm microvascular function in age-matched black ( n=56 ) and white subjects ( n=62 ) using intra-arterial agonist infusion and venous occlusion plethysmography . In normotensive subjects ( n=70 ; 34 black and 36 white normotensives ) , methacholine- , sodium nitroprusside- , and verapamil-induced vasodilation was equivalent in black and white subjects . In hypertensive subjects ( n=48 ; 22 black and 26 white hypertensives ) , the vasodilator response to methacholine  was markedly lower in black subjects compared with white subjects ( P < 0.001 ) . The vasodilator responses to sodium nitroprusside and verapamil  , however , were equivalent in black and white hypertensive subjects . Acute  ascorbic acid infusion  improved the methacholine response equally in black and white hypertensive patients , suggesting that a difference in a rapidly reversible form of oxidative stress does not explain these findings . Thus , the present study demonstrates important racial differences in vascular function and a marked impairment in endothelial vasomotor function in black patients with hypertension . Further studies will be required to eluci date the mechanisms and determine whether these insights will lead to more appropriately tailored management of hypertension and its complications In this prospect i ve investigation , all children enrolled in the public third- grade classrooms of an entire county ( n=474 ) had blood pressure measured both at rest and during a stressful television video game . Examinations were repeated in 4 subsequent years when cohort children as well as newly enrolled children were in grade s 4 , 5 , 7 , and 8 . Both crosssectional and longitudinal analyses indicated that black children demonstrated significantly greater systolic and diastolic pressor reactivity than white children . These data suggest that ethnic differences in children 's pressor reactivity presage ethnic differences in adulthood hypertension OBJECTIVES To determine arterial elasticity in normotensives and in treated and untreated hypertensive Black and White subjects . METHODS A prospect i ve multicenter , controlled clinical trial evaluated large ( C- ) and small ( C2 ) artery elasticity indices among 3 groups : 1 ) normotensive subjects with or without a family history of hypertension ; 2 ) controlled and treated hypertensive subjects ; and 3 ) untreated and uncontrolled hypertensive subjects .  Blood pressure was measured using a mercury manometer and arterial compliance or elasticity was determined using a CVProfilor DO-2020 CardioVascular Profiling System ( Hypertension Diagnostics , Inc , Eagan , Minn ) . These parameters were measured in triplicate 3 minutes apart in a r and om sequence , with the patient in a supine position . Two-way ANOVA was used for statistical evaluation . RESULTS One hundred seventy eight subjects met stratification and enrollment criteria . The mean age was 46 years . 109 were White and 69 were Black . [ table : see text ] CONCLUSION Small and large arterial elasticity indices are reduced as hypertension status worsens . Age and height were important covariates of C1 and C2 . Race was not found to be a significant predictor of either C1 or C2 . Large and small artery elasticity indices do not differ between White and Black subjects with varying degrees of hypertension after adjusting for covariates . More studies with a larger number of subjects are required BACKGROUND Vasodilator reactivity is attenuated in normotensive blacks , and this may contribute to their enhanced susceptibility to hypertension and its complications . However , the mechanisms responsible for this phenomenon are unknown . We therefore studied nitric oxide (NO)-dependent and -independent vasorelaxation in healthy blacks and whites to investigate the nature of racial differences in vasodilator function . METHODS AND RESULTS Forearm flow responses to intra-arterial infusion of increasing doses of acetylcholine ( a vasodilator that stimulates endothelial release of NO ) , sodium nitroprusside ( an exogenous NO donor ) , and isoproterenol ( a beta-adrenergic agonist whose vasodilator effect stems from the combination of direct smooth muscle stimulation and endothelial NO release ) were studied in 18 normotensive whites and 18 blacks by use of strain-gauge plethysmography . A blunted vasodilator response to acetylcholine ( 7.2+/-1.1 versus 14.4+/-1.8 mL. min-1 . dL-1 ; P<0.001 ) and sodium nitroprusside ( 8.2+/-1.1 versus 12.1+/-1.3 mL. min-1 . dL-1 ; P<0.001 ) was observed in blacks compared with whites , suggesting decreased cGMP-mediated smooth muscle relaxation . The vasodilator effect of isoproterenol was lower in blacks than in whites both before ( 10.9+/-1.7 versus 14.9+/-1.5 mL. min-1 . dL-1 ; P=0.006 ) and after NG-monomethyl-L-arginine ( 6.1+/-1.2 versus 10 . 1+/-0.8 mL. min-1 . dL-1 ; P<0.001 ) , implying that cAMP-dependent vasodilator response to isoproterenol is diminished in blacks . No significant difference was observed in the hyperemic response to forearm ischemia . CONCLUSIONS Compared with whites , healthy blacks have reduced vasodilation in response to NO-dependent and -independent stimuli . This difference seems to be related to an attenuation in cyclic nucleotide-mediated vascular smooth muscle relaxation and may play a role in the increased prevalence of hypertension and its complications in blacks The health and life expectancy of Americans has dramatically improved during the past several decades , but racial and ethnic minorities have not benefited equally from this progress . Differences in health outcomes between majority and minority population s , commonly referred to as racial or ethnic disparities in health , are the result of several factors operating in complex sociologic , cultural , political , economic , and health care context s. Until recently , curricula addressing racial and ethnic health disparities focused on factors outside the health care system , including socioeconomic disadvantage and lack of health insurance ( 1 ) , but some publications ( 25 ) , culminating in 2002 with the Institute of Medicine report , Unequal Treatment : Confronting Racial and Ethnic Disparities in Health Care , have highlighted the fact that racial and ethnic minoritieseven those with equivalent access to the health care systemreceive lower- quality care than white patients for many medical conditions ( 6 ) . As a result , increased attention is now focused on addressing racial and ethnic disparities in health care ( hereafter referred to as health care disparities ) as a component of addressing racial and ethnic disparities in health ( hereafter referred to as health disparities ) ( 7 , 8) . Emerging consensus among national experts suggests that without new and more effective interventions , health disparities will be difficult to eliminate ( 9 ) , and they may become an even larger problem as racial and ethnic minorities become a larger proportion of the U.S. population ( 10 ) . Key stakeholders need to engage at many levels to eliminate disparities , including at the community and societal levels . However , considering the significance of the physicianpatient relationship in health care delivery , interventions by individual physicians will be an important component of an overall strategy to reduce health care disparities . Several surveys show that many physicians remain unaware of health care disparities nationally and in their own practice s ( 1113 ) . The Institute of Medicine 's report recommends that health professionals receive training to better underst and and address disparities ( 6 ) . However , few curricula on health disparities exist , and there are no well-accepted guidelines on what and how to teach about this complex topic . This report presents the work of the Society of General Internal Medicine Health Disparities Task Force to develop guidelines for medical education on disparities in health and health care . We provide learning objectives , suggested content , methods for teaching , and a set of current re sources . Although they were developed primarily for teaching medical students , residents , and practitioners in primary care , our general recommendations should apply to learners in any specialty . The Task Force has also developed recommendations for system-level and environment-of-care interventions to eliminate health care disparities , which are as important as recommendations for training individual practitioners but are beyond the scope of this report . Methods The Society of General Internal Medicine is an international organization that comprises internal medicine physicians and others who combine patient care with education and research in primary care internal medicine . The Task Force includes volunteers from the Society of General Internal Medicine membership , many of whom teach about ethics , health disparities , and cross-cultural care at their institutions . The Task Force convened a series of meetings from 2002 to 2005 , which included several conference calls , e-mail exchanges , and 4 face-to-face meetings . After the first meeting , Task Force teams completed a needs assessment and literature review . The entire Task Force then contributed to several versions of the recommendations . Subsequent meetings served to refine and tailor iterative versions of both the literature review and recommendations , which informed each other . Final recommendations were developed by a consensus , although various interpretations remain among members of the Task Force in the application of specific principles . Needs Assessment Few studies have formally assessed the need for health disparities training . Recent surveys on cross-cultural care demonstrate that resident physicians ' self-reported preparedness to deliver cross-cultural care lags well behind preparedness in other clinical and technical areas ( 14 , 15 ) . A national study on resident physicians reported that residents were receiving the message that health care disparities are important and that physicians should play a role in eliminating them , but they had not received guidance on how to do so . As a result , they developed coping behaviors rather than skills ( 16 ) . To supplement these studies , the Task Force conducted its own brief needs assessment survey with the assistance of the Institute for Ethics at the American Medical Association . The survey was sent to 60 r and omly selected internal medicine program directors nationwide , 22 of whom responded within the 1-month time frame ( 37 % response rate ) . Most of the 22 respondents ( 86 % ) reported teaching some information about health disparities , and none reported offering a lot of training . However , 77 % agreed that learning about health disparities was associated with better quality of care , and 73 % reported that a resident 's level of interest was not a barrier to teaching : health disparities . Rather , shortages of qualified faculty and lack of st and ardized curricula were often noted as barriers . Adding to the need for concrete guidance in this domain , the Liaison Committee on Medical Education , which sets st and ards for undergraduate medical education , required in 2004 that medical schools document objectives relating to the development of skills in cultural competence , indicate where in the curriculum students are exposed to such material , and demonstrate the extent to which the objectives are being achieved ( 17 ) . The Accreditation Council on Graduate Medical Education , which accredits residency training programs , has also included cultural sensitivity as a skill set in its core competencies for residency training : Programs must teach and monitor residents ' ability to demonstrate sensitivity and responsiveness to patients ' culture , age , gender , and disabilities ( 18 ) . The American Board of Medical Specialties and the Accreditation Council on Graduate Medical Education have created a toolbox of re sources for monitoring professionalism that includes useful material s for assessing residents in these domains ( 19 ) . Because these accreditation requirements have been implemented , new curricula ( 2022 ) and suggested st and ards for training programs ( 2325 ) have begun to emerge , although none are widely accepted yet . Literature 
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The available data indicate that compared to normotensive whites , normotensive black people have enhanced vascular reactivity to sympathetic stimulation , attenuated responses to vasodilators , and a relatively narrow vascular lumen diameter .
Of these mechanisms , the reduced vasodilation and reduced nitric oxide bioavailability in the vascular wall seem to form the most important distinction between resistance vessel properties of black and white participants