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IMPORTANCE: A genetic variant in the TTR gene (rs76992529; Val122Ile), present more commonly in individuals with African ancestry (population frequency: 3%-4%), causes misfolding of the tetrameric transthyretin protein complex that accumulates as extracellular amyloid fibrils and results in hereditary transthyretin amyloidosis. OBJECTIVE: To estimate the association of the amyloidogenic Val122Ile TTR variant with the risk of heart failure and mortality in a large, geographically diverse cohort of Black individuals. DESIGN, SETTING, AND PARTICIPANTS: Retrospective population-based cohort study of 7514 self-identified Black individuals living in the US participating in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study with genetic data available and without heart failure at baseline. The participants were enrolled at the baseline visit (2003-2007). The end of follow-up for the majority of outcomes was on December 31, 2018. All-cause mortality data were available through December 31, 2020. EXPOSURES: TTR Val122Ile (rs76992529) genotype. MAIN OUTCOME AND MEASURES: The primary outcome was incident heart failure (first hospitalization for heart failure or death due to heart failure). The secondary outcomes were heart failure mortality, cardiovascular mortality, and all-cause mortality. The multivariable Cox proportional hazards regression analyses were adjusted for genetic ancestry and demographic, clinical, and social factors. RESULTS: Among 7514 Black participants (median age, 64 years [IQR, 57-70 years]; 61% women), the population frequency of the TTR Val122Ile variant was 3.1% (232 variant carriers and 7282 noncarriers). During a median follow-up of 11.1 years (IQR, 5.9-13.5 years), incident heart failure occurred in 535 individuals (34 variant carriers and 501 noncarriers) and the incidence of heart failure was 15.64 per 1000 person-years among variant carriers vs 7.16 per 1000 person-years among noncarriers (adjusted hazard ratio [HR], 2.43 [95% CI, 1.71-3.46]; P

Introduction: Resilience—which we define as the “ability to bounce back from stress”—can foster successful aging among older, racially and ethnically diverse women. This study investigated the association between psychological resilience in the Women’s Health Initiative Extension Study (WHI-ES) and three constructs defined by Staudinger’s 2015 model of resilience and aging: (1) perceived stress, (2) non-psychological resources, and (3) psychological resources. We further examined whether the relationship between resilience and key resources differed by race/ethnicity. Methods: We conducted a secondary analysis on 77,395 women aged 62+ (4475 Black or African American; 69,448 non-Hispanic White; 1891 Hispanic/Latina; and 1581 Asian or Pacific Islanders) who enrolled in the WHI-ES, which was conducted in the United States. Participants completed a short version of the Brief Resilience Scale one-time in 2011. Guided by Staudinger’s model, we used linear regression analysis to examine the relationships between resilience and resources, adjusting for age, race/ethnicity, and stressful life events. To identify the most significant associations, we applied elastic net regularization to our linear regression models. Findings: On average, women who reported higher resilience were younger, had fewer stressful life events, and reported access to more resources. Black or African American women reported the highest resilience, followed by Hispanic/Latina, non-Hispanic White, and Asian or Pacific Islander women. The most important resilience-related resources were psychological, including control of beliefs, energy, personal growth, mild-to-no forgetfulness, and experiencing a sense of purpose. Race/ethnicity significantly modified the relationship between resilience and energy (overall interaction p = 0.0017). Conclusion: Increasing resilience among older women may require culturally informed stress reduction techniques and resource-building strategies, including empowerment to control the important things in life and exercises to boost energy levels.

Childhood adversities, including neglect, abuse, and other indicators of family dysfunction, are associated in adulthood with risk factors for poor cognitive and mental health. However, the extent to which these experiences are associated with adulthood cognition-related quality of life and risk for dementia is unknown.To determine the association of 10 adverse childhood experiences (ACEs) with neuropsychiatric outcomes among former National Football League (NFL) players.This cross-sectional analysis used data from the Football Player's Health Study at Harvard University, an ongoing longitudinal cohort study from January 30, 2015, to November 19, 2021, of former NFL players.Ten ACEs were assessed using the Adverse Childhood Experiences Questionnaire.Dementia symptoms were assessed using the AD8: The Washington University Dementia Screening Test; cognition-related quality of life was assessed with the short form of the Quality of Life in Neurological Disorders; depression was assessed with the Patient Health Questionnaire-9; anxiety was assessed with the Generalized Anxiety Disorder-7; and pain intensity and pain interference in daily life were assessed with the Brief Pain Inventory. Risk ratios (RRs) assessing the association between ACEs and neuropsychiatric outcomes were estimated using generalized estimating equations, adjusted for age, race, and childhood socioeconomic status, and further adjusted for playing position, concussions incurred during football play, and number of seasons played in the NFL.A total of 1755 men (mean [SD] age, 57.2 [13.5] years) who were former professional football players were included in the analysis. Five hundred twenty players (29.6%) identified as Black, 1160 (66.1%) identified as White, and 75 (4.3%) identified as other race or ethnicity. Players with 4 or more ACEs were at 48% greater risk of a positive screen for dementia (RR, 1.48 [95% CI, 1.22-1.79]), and at significantly greater risk of every other neuropsychiatric outcome except anxiety (RR range, 1.62 [95% CI, 1.09-2.39] to 1.74 [95% CI, 1.27-2.40]) compared with players with no ACEs. Further adjustment for concussions incurred during playing years attenuated these associations, although some were still significant (adjusted RR range, 1.32 [95% CI, 1.10-1.58] to 1.56 [95% CI, 1.15-2.11]). ACEs were also associated with concussion symptoms; players with 4 or more ACEs had a 60% increased risk of being in the top quartile of concussion symptoms (RR, 1.60; 95% CI, 1.12-2.28) compared with players with no ACEs.These findings suggest that ACEs may be associated with dementia symptoms among former NFL players. Moreover, ACEs should be investigated among professional football players and other populations as a prospective indicator of persons at high risk of concussion. These findings further suggest that treatment of psychological trauma in addition to treatment of physical injury may improve neuropsychiatric health in former NFL players.

Increased risk of neurological and psychiatric conditions after traumatic brain injury (TBI) is well-defined. However, cardiovascular and endocrine comorbidity risk after TBI in individuals without these comorbidities and associations with post-TBI mortality have received little attention.To assess the incidence of cardiovascular, endocrine, neurological, and psychiatric comorbidities in patients with mild TBI (mTBI) or moderate to severe TBI (msTBI) and analyze associations between post-TBI comorbidities and mortality.This prospective longitudinal cohort study used hospital-based patient registry data from a tertiary academic medical center to select patients without any prior clinical comorbidities who experienced TBI from 2000 to 2015. Using the same data registry, individuals without head injuries, the unexposed group, and without target comorbidities were selected and age-, sex-, and race-frequency-matched to TBI subgroups. Patients were followed-up for up to 10 years. Data were analyzed in 2021.Mild or moderate to severe head trauma.Cardiovascular, endocrine, neurologic, and psychiatric conditions were defined based on International Classification of Diseases, Ninth Revision (ICD-9) or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). Associations between TBI and comorbidities, as well as associations between the comorbidities and mortality, were analyzed.A total of 4351 patients with mTBI (median [IQR] age, 45 [29-57] years), 4351 patients with msTBI (median [IQR] age, 47 [30-58] years), and 4351 unexposed individuals (median [IQR] age, 46 [30-58] years) were included in analyses. In each group, 45% of participants were women. mTBI and msTBI were significantly associated with higher risks of cardiovascular, endocrine, neurologic, and psychiatric disorders compared with unexposed individuals. In particular, hypertension risk was increased in both mTBI (HR, 2.5; 95% CI, 2.1-2.9) and msTBI (HR, 2.4; 95% CI, 2.0-2.9) groups. Diabetes risk was increased in both mTBI (HR, 1.9; 95% CI, 1.4-2.7) and msTBI (HR, 1.9; 95% CI, 1.4-2.6) groups, and risk of ischemic stroke or transient ischemic attack was also increased in mTBI (HR, 2.2; 95% CI, 1.4-3.3) and msTBI (HR, 3.6; 95% CI, 2.4-5.3) groups. All comorbidities in the TBI subgroups emerged within a median (IQR) of 3.49 (1.76-5.96) years after injury. Risks for post-TBI comorbidities were also higher in patients aged 18 to 40 years compared with age-matched unexposed individuals: hypertension risk was increased in the mTBI (HR, 5.9; 95% CI, 3.9-9.1) and msTBI (HR, 3.9; 95% CI, 2.5-6.1) groups, while hyperlipidemia (HR, 2.3; 95% CI, 1.5-3.4) and diabetes (HR, 4.6; 95% CI, 2.1-9.9) were increased in the mTBI group. Individuals with msTBI, compared with unexposed patients, had higher risk of mortality (432 deaths [9.9%] vs 250 deaths [5.7%]; P .001); postinjury hypertension (HR, 1.3; 95% CI, 1.1-1.7), coronary artery disease (HR, 2.2; 95% CI, 1.6-3.0), and adrenal insufficiency (HR, 6.2; 95% CI, 2.8-13.0) were also associated with higher mortality.These findings suggest that TBI of any severity was associated with a higher risk of chronic cardiovascular, endocrine, and neurological comorbidities in patients without baseline diagnoses. Medical comorbidities were observed in relatively young patients with TBI. Comorbidities occurring after TBI were associated with higher mortality. These findings suggest the need for a targeted screening program for multisystem diseases after TBI, particularly chronic cardiometabolic diseases.

Introduction: African Americans (AAs) have among the highest prevalence of type 2 diabetes in the U.S. Research has shown that positive affect and supportive networks are associated with better health outcomes and may improve regulation of physiological processes. We examined the extent to which psychosocial resources were protective of diabetes outcomes among a sample of 5,306 AAs. Hypothesis: Psychosocial resource measures are inversely associated with prediabetes and diabetes [defined by hemoglobin (Hb)A1c categories] and prevalent diabetes (defined by self-report diabetes status and medication use). Methods: Using data from the Jackson Heart Study (JHS), we evaluated the cross-sectional associations of four psychosocial-resource indicators (social support, optimism, religiosity, social networks) with two diabetes outcomes [1) HbA1c categories: normal (HbA1c ≤ 5.7%), at risk/pre-diabetic (5.7% < HbA1c < 6.5%), diabetic (HbA1c ≥ 6.5%) and 2) prevalent diabetes (vs. no diabetes)]. For each psychosocial-resource measure, we created high vs. low categories (median split) and continuous standard deviation (SD) units. Associations with HbA1c categories were examined using multinomial logistic regression to estimate odds ratios (OR 95% confidence interval-CI) of pre-diabetes (vs. normal) and diabetes (vs. normal). Associations with prevalent diabetes were examined using Poisson regression to estimate prevalence ratios (PR 95% CI) of diabetes (vs. no diabetes). Models adjusted for demographics, SES, waist circumference, health behaviors, and depression. Results: Participants with diabetes reported fewer psychosocial resources than those with pre-diabetes and normal HbA1c ( p social support was associated with an 11% lower odds of pre-diabetes (vs. normal HbA1c) (OR 0.89, 95% CI 0.81-0.99). High (vs. low) religiosity was associated with an increased odds of diabetes (vs. normal Hba1c) (OR 1.29, 95% CI 1.01-1.64) after full adjustment. Optimism and social networks were only associated with lower diabetes prevalence after adjustment for demographics and education, respectively. Conclusion: With the exception of religiosity, psychosocial-resource measures were inversely associated with diabetes. Social support and social networks, especially, should be considered when addressing the reduction of diabetes burden among AAs.

The MECA study is unique in that it will study CVD resilience in blacks at both the individual and community (census tract) level in the Atlanta Metropolitan Area. It is well established that blacks suffer from greater cardiovascular morbidity and mortality than whites in the United States. Not all blacks suffer from poor cardiovascular health, some individuals manage to live long healthy lives without ever developing cardiovascular conditions. The causes of this resilience are not known. Both individual and community level factors may be responsible for cardiovascular risk and resilience in blacks. The first stage of the MECA study was to identify “at risk” and resilient communities based on their rates of CVD related ED visits, hospitalizations and mortality. Objectives: To determine if in fact a wide distribution of CVD rates exist among Blacks in census tracts in Metro Atlanta. To determine if there were still large differences in rates when black household income was controlled for. Methods: Count data on CVD related emergency department and hospitalizations for blacks aged 35-64 living in census tracts in the Atlanta--Athens-Clarke--Sandy Springs combined statistical area during 2010-2014 were obtained from the Georgia Hospital Association. CVD mortality data for the same population for the same time period were obtained from the Georgia Department of Public Health. In order to control for the socioeconomic status, age and gender distribution of the neighborhoods, negative binomial regression models controlling for median black household income, percent of 5-year age groupings, and percent male were estimated for each of the outcomes. Residuals in top 25% were considered to be “at risk tracts (high rate) while residuals in the bottom 25% were considered resilient (low rate tracts). Results: 106 tracts were resilient for at least 2 of the 3 outcomes, 188 were “at risk” for 2 out of 3 outcomes. Both types of tracts were located throughout the Atlanta metropolitan area. Mean black household income in the tracts are similar (resilient: $46,335, “at risk”: $44,721). Black CVD hospitalization event rate was 28 vs. 132 per 1000 population(p Conclusion: We have identified census tracts in Metro Atlanta that have large differences in premature CVD outcomes for Blacks despite having similar mean income levels. The next phase of the MECA study will examine census tract and survey data to elucidate what contextual (demographic, food environment, reported neighborhood characteristics) and individual level (behavioral, psychological, social) factors may be associated with the different rates of CVD in resilient and “at risk” census tracts.

Background: While the prevalence of cardiovascular health metrics or Life’s Simple Seven (LSS) has been shown to be far from optimal in the US, such information has been predominantly reported in Caucasians. The burden of cardiovascular disease among African Americans underscores the need to evaluate the prevalence and secular trends of LSS in other ethnic groups. Objective: To test the hypothesis that the prevalence of the LSS is far from ideal among participants of the Jackson Heart Study. Methods: We analyzed LSS with 3,500 African Americans from the Jackson Heart Study, using data from their first clinic visit (2000-2004). Standard methods were used to measure blood pressure, glucose, body mass index (BMI), and cholesterol. Information on physical activity, smoking, and diet was collected with interviewer-administered questionnaires. Each of the LSS metrics (smoking status, diet, physical activity, BMI, fasting blood glucose, total cholesterol, and blood pressure) was categorized as poor, intermediate, or ideal, as defined by the AHA guidelines. Results: The mean age at baseline was 56.9 ± 12.2 years and 2,350 participants (67%) were women. Among men, the prevalence of having 0, 1, 2, 3, 4, 5, 6, and 7 ideal cardiovascular health metrics was 6.6%, 25.8%, 32.7%, 21.6%, 10.6%, 2.3%, 0.4%, and 0%, respectively. Corresponding values for women were 3.2%, 28.1%, 32.9%, 22.3%, 10.1%, 2.9%, 0.38%, and 0%. While about two-thirds of men and women reported ideal smoking status, almost none reported ideal diet quality, and few met recommendations for BMI and blood pressure ( Figure) . Conclusions: Our data are consistent with less than optimal prevalence of cardiovascular health metrics in both men and women from the Jackson Heart Study. The lower prevalence of meeting ideal recommendations for diet, physical activity, BMI, and blood pressure underscores the need for targeted interventions to improve these modifiable lifestyle factors in order to reduce the burden of cardiovascular disease among African-Americans.

Introduction: African Americans (AA) have a higher risk for cardiovascular disease (CVD) than Whites. This disparity has been attributed to risk factors such as hypertension, diabetes, and obesity. This disparity has also been attributed to psychosocial factors across groups. Using Jackson Heart Study (JHS) data, we examined the associations of negative affect and stress measures with CVD risk factors and prevalent CVD among AA. Hypothesis: Negative affect and stress measures are associated with prevalent CVD risk factors and CVD among men and women in the JHS. Methods: Cross-sectional associations of negative affect (cynicism, anger in, anger out, and depressive symptoms) and stress (global stress, weekly stress, and major life events) with prevalent BMI, hypertension, diabetes and CVD were examined among 5,301 participants 34-85 years old (women=3,360; men=1,941). We estimated mean differences in BMI and prevalence ratios (PR) of hypertension, diabetes and CVD with measures of negative affect and stress and adjusted for demographic and clinical risk factors. Results: Men had higher cynical distrust and anger in scores than women (p Conclusion: Efforts to reduce disparities in CVD may need to address environmental and psychosocial factors that place AA at higher risk.

Objectives. Prior research has reported an association between perceived discrimination and health outcomes among African Americans, and there is growing interest in the pathways in which it gets ‘under the skin.’ One such pathway may be through the association with behavioral risk factors. Using Jackson Heart Study data, we examined whether perceived reports of discrimination were associated with behavioral risk factors among African Americans. Methods. Cross-sectional associations of perceived reports of everyday discrimination, lifetime discrimination, and burden of lifetime discrimination with smoking status, physical activity, percent calories from fat in diet, and hours of sleep were examined among 4,939 participants 20–95 years old (women=3,123; men=1,816). We estimated odds ratios (OR) of current smoking and mean differences in physical activity, fat in diet and hours of sleep with measures of discrimination and adjusted for age and socioeconomic status. Results. Men were more likely to smoke than women, and had higher physical activity scores. Women reported slightly more hours of sleep than men. Men and women reported similar percentages of calories from fat in diet. After adjustment for age and socioeconomic status, perceived everyday discrimination was associated with more smoking and a greater percentage of calories from fat in diet in men and women (OR for smoking: 1.13, 95%CI 1.00–1.28 and 1.19, 95%CI 1.05–1.34; mean difference in percent calories from fat in diet: 0.37, p Conclusions. Behavioral risk factors offer a potential mechanism through which perceived discrimination affects health in African Americans.

Background: The presence of chronic kidney disease is greater in African Americans than in non-Hispanic whites. Though there is data to show a relation between endothelial dysfunction and end-stage kidney disease, the relation to mild and moderate chronic kidney disease (particularly in African Americans) is unclear. Methods and Results: Digital arterial tonometry was performed during Exam 2 and 3 of the Jackson Heart Study using the endoPAT2000. Data from digital arterial tonometry included baseline pulse wave amplitude (BPA) as a measure of endothelial tone and reactive hyperemic index (F-RHI) as a measure of endothelial function. For this study, the estimated glomerular filtration rate (eGFR) was calculated using the MDRD equation. Those participants with eGFR < 60 ml/min/1.73m2 were defined as having CKD. Participants with eGFR < 15 ml/min/1.73m2 were excluded from the analysis. Microalbuminuria in this study was defined as a urinary albumin:creatinine ratio ≥ 17mg/g in men and ≥ 25 mg/g in women. We compared the differences in least square means adjusted for age and sex, and adjusted for multiple traditional clinical covariates using a generalized linear model. Results: There were 834 participants in the study population (mean age 58.5 years, 61% women); 87 (10.4%) participants with CKD and 108 (13.0%) with microalbuminuria. In age and sex adjusted samples, we found that both BPA and F-RHI were significantly associated with CKD in the pooled samples. However in multivariable adjusted analysis the relation was no longer significant in either the pooled or sex-specific samples. In the multivariable adusted analysis,BPA was significantly (P=0.036) associated with microalbuminuria in men and F-RHI was weakly significantly (P=0.08) associated with microalbuminuria in women. Conclusion: We found that endothelial dysfunction as measured by digital arterial tonometry is not significantly associated with chronic kidney disease. There is an association of endothelial tone in men and endothelial dysfunction in women with microalbuminuria.

Health of African Americans is seriously threatened by unremitting epidemics of diabetes and cardiovascular disease (CVD). However, the role of metabolic syndrome in the African-American population has not been investigated widely. This study examined the prevalence of metabolic syndrome and assessed its cross-sectional relationship to CVD in the Jackson Heart Study (JHS) cohort.A total of 5,302 participants agedor=21 years who were recruited at baseline during 2000-2004 were analyzed for this study. Adjusted odds ratios (ORs) were estimated in a logistic regression analysis for coronary heart disease (CHD) and cerebrovascular disease (CBD) in those with and without coexisting metabolic syndrome. Diabetic participants were excluded.Among those aged 35-84 years, metabolic syndrome prevalence was 43.3% in women and 32.7% in men. Elevated blood pressure (70.4%), abdominal obesity (64.6%), and low HDL cholesterol (37.2%) were highly prevalent among those with metabolic syndrome. Prevalence rates for CVD, CHD, and CBD were 12.8, 8.7, and 5.8%, respectively. After adjustment for age and sex, metabolic syndrome was associated with increased age- and sex-adjusted ORs for CVD (OR 1.7 [95% CI 1.4-2.1]), CHD (1.7 [1.4-2.2]), and CBD (1.7 [1.3-2.3]) compared with those without CVD, CHD, or CBD.Metabolic syndrome prevalence in the JHS is among the highest reported for population-based cohorts worldwide and is significantly associated with increased ORs for CVD, CHD, and CBD. Abdominal obesity, increased blood pressure, and low HDL cholesterol (without triglyceride elevation) are surprisingly prominent. A high prevalence of low HDL emerges as a leading contributor to metabolic syndrome among African Americans in this large African-American cohort.

The Jackson Heart Study Undergraduate Training Center (UTC) at Tougaloo College was developed to increase the numbers of African-American students entering public health and health related fields. The UTC includes a scholars program for undergraduate students at Tougaloo College, three four-week programs for high school students called the SLAM (science, language arts, and mathematics) workshops, and an introductory epidemiology course for healthcare professionals and graduate students. The scholars program recruits 12 Tougaloo College freshmen annually for the duration of their undergraduate education. As of the 2005 summer, 512 students have enrolled in the SLAM workshops. The introduction to epidemiology course has provided training for 155 individuals from 1999 to 2004. This paper documents the need for this program based on the conspicuously small proportion of African Americans who are health practitioners in Mississippi. The content and selection process for each program is described, and a summary of the enrollment history, characteristics of the program participants, and their accomplishments is presented. Finally, the methods of program assessment and tracking are discussed.

To determine the incidence rate of cardiovascular disease (CVD) and its association with conventional and less well-established risk factors in African Americans with diabetes, we studied 741 African Americans aged 45 to 64 years with diabetes, in the Atherosclerosis Risk in Communities (ARIC) study. Risk factors were measured from 1987 to 1989, and incident CVD (n = 143 coronary heart disease (CHD) or stroke events) was ascertained through 1998. The crude incidence rate (per 1000 person-years) of CVD was 22.5 (11.9 for CHD and 12.0 for stroke). After multivariate adjustments, total cholesterol, prevalent hypertension and current smoking were significantly and positively associated with incident CVD among these African Americans with diabetes. Among the non-conventional risk factors, serum creatinine, factor VIII, von Willebrand factor, and white blood cell count were positively and serum albumin negatively and independently associated with CVD incidence. Adjusted relative risks for highest versus lowest tertiles of these risk factors ranged from 1.77 to 2.13. This study confirms that the major risk factors (hypercholesterolemia, hypertension and smoking) are important determinants of CVD in African Americans with diabetes. In addition, several blood markers of hemostasis or inflammatory response and elevated serum creatinine also proved to be CVD risk factors in African Americans with diabetes.

Background The pathophysiology of mental stress–induced myocardial ischemia, which occurs at lower heart rates than during physical stress, is not well understood. Methods and Results The Psychophysiological Investigations of Myocardial Ischemia Study (PIMI) evaluated the physiological and neuroendocrine functioning in unmedicated patients with stable coronary artery disease and exercise-induced ischemia. Hemodynamic and neurohormonal responses to bicycle exercise, public speaking, and the Stroop test were measured by radionuclide ventriculography, ECG, and blood pressure and catecholamine monitoring. With mental stress, there were increases in heart rate, systolic blood pressure, cardiac output, and systemic vascular resistance that were correlated with increases in plasma epinephrine. During exercise, systemic vascular resistance fell, and there was no relationship between the hemodynamic changes and epinephrine levels. The fall in ejection fraction was greater with mental stress than exercise. During mental stress, the changes in ejection fraction were inversely correlated with the changes in systemic vascular resistance. Evidence for myocardial ischemia was present in 92% of patients during bicycle exercise and in 58% of patients during mental stress. Greater increases in plasma epinephrine and norepinephrine occurred with ischemia during exercise, and greater increases in systemic vascular resistance occurred with ischemia during mental stress. Conclusions Mental stress–induced myocardial ischemia is associated with a significant increase in systemic vascular resistance and a relatively minor increase in heart rate and rate-pressure product compared with ischemia induced by exercise. These hemodynamic responses to mental stress can be mediated by the adrenal secretion of epinephrine. The pathophysiological mechanisms involved are important in the understanding of the etiology of myocardial ischemia and perhaps in the selection of appropriate anti-ischemic therapy.

Psychological factors are linked to outcomes in coronary artery disease (CAD) pts but the mechanisms are obscure. The PIMI is a NIH multicenter study designed to test the overall hypothesis that manifestations and expressions of ischemia are influenced by specific psycho-physiologic mechanisms. Accordingly, 200 pts, mean age 62, with CAD and ischemia responses on treadmill were studied. Ambulatory ECG (AECG) monitoring, psychological instrument batteries and plasma biochemical tests were applied to identify mechanisms associated with ischemia during daily life, exercise and mental stress without influence of cardiac medications. Daily life ischemia (AECG) occurred in 41% of pts (95% with ischemia were asymptomatic) and was associated with lower hostility (p l 0.01) and anger expression (p l 0.03) scores compared with those without daily life ischemia. An inverse association between magnitude of daily life ischemia and these scores was observed. No differences were found for depression (Beck) or anxiety scores. On treadmill all pts had ischemia (ST segment depression) but 44% had angina. Angina expression was associated with higher depression (p =0.002), anxiety (State, p = 0.002 and Trait, p = 0.01) and autonomic perception (p = 0.05) scores than no angina. Depression best predicted time to angina (Cox model, p = 0.007). During mental stress (Stroop and speech tasks) ischemia (radionuclide ventriculogram (RVG) or ST segment abnormalities) occurred in 79% of pts (95% with ischemia were asymptomatic) and associated with higher Reward, Dependence, (Temperament and Character Inventory, p l 0.02) and level of irritation during Stroop task (p l 0.01). Plasma norepinephrine remained low, but epinephrine doubled and systolic pressure increased. No associations were found for medical or demographic factors examined. During bicycle exercise ischemia (RVG abnormality) occurred in 94% of pts (64% with ischemia were asymptomatic) yet norepinephrine increased three-fold. In summary, daily life ischemia (usually asymptomatic) is associated with suppressed hostility, anger and emotion but not depression or anxiety. Mental stress ischemia (mostly asymptomatic and with epinephrine release) is related to temperament characteristics. Exercise stress ischemia, on the other hand, more often evokes symptoms and marked norepinephrine release but symptom expression seems dependent upon depression, anxiety and autonomic perception. Mechanisms responsible for ischemia evoked in different settings and its symptomatic expression involve complex interactions of behavioral, physiological and psychophysiological factors.

Taylor , W. H. (Portland State College, Portland, Ore.), M. L. Taylor, and D. F. Eames . Two functionally different dihydroorotic dehydrogenases in bacteria. J. Bacteriol. 91: 2251–2256. 1966.—We have investigated the relationship between the two kinds of dihydroorotic dehydrogenases produced by bacteria. A pseudomonad, capable of growth on a salts medium with glucose, aspartate, glycerol, or orotate as the carbon source, was isolated from lake bank mud. A particle-bound dihydroorotic dehydrogenase, similar to the biosynthetic enzyme in Escherichia coli , was formed by the pseudomonad when the carbon source was orotate, glucose, glycerol, or aspartate. A soluble, degradative nicotinamide adenine dinucleotide phosphate-linked dihydroorotic dehydrogenase, as well as the particle-bound biosynthetic enzyme, was formed when the pseudomonad was cultivated on orotate. The biosynthetic enzyme links to oxygen or ferricyanide, but not to pyridine nucleotides. Zymobacterium oroticum , when cultivated on glucose, contained only the biosynthetic type of dihydroorotic dehydrogenase. The presence of two functionally different dihydroorotic dehydrogenases in the pseudomonad was suggested on the basis of the following observations: (i) the two enzyme activities were separated by centrifugation; (ii) the pyridine nucleotide-linked activity was formed only when orotate was present in the growth medium; and (iii) the biosynthetic enzyme was stable to storage at −20 C for 4 months, whereas the degradative enzyme activity was destroyed by storage under these conditions.

Taylor, W. Herman (Portland State College, Portland, Ore.), and Mary L. Taylor . Enzymes of the pyrimidine pathway in Escherichia coli . II. Intracellular localization and properties of dihydroorotic dehydrogenase. J. Bacteriol. 88: 105–111. 1964.—Intracellular localization of three enzymes of the pyrimidine pathway in Escherichia coli was studied. Dihydroorotic dehydrogenase was found to be associated with the membrane portion of lysed spheroplasts. Centrifugal fractionation of cell-free extracts showed all the dihydroorotic dehydrogenase activity to be associated with large structures, probably cell wall-membrane fragments. In contrast, all orotidylic decarboxylase activity was found in the cytoplasm in both lysed spheroplasts and cell-free extracts. Aspartate transcarbamylase activity appeared to be particulate in repressed cells, but only 25% was particulate in derepressed cells. Dihydroorotic dehydrogenase was shown to be bound to oxidative particles by oxygen uptake and orotate production from dihydroorotate. A ferricyanide reduction assay, suitable for measuring soluble and particulate enzyme, was devised for dihydroorotic dehydrogenase. Soluble dihydroorotic dehydrogenase was prepared by use of deoxycholate. A 20-fold purification of the enzyme compared to whole-cell activity was achieved by ammonium sulfate fractionation of the deoxycholate-soluble enzyme. Although cytochromes were implicated by cyanide inhibition of aerobic orotate production by particles, the purified enzyme appeared to be separated from the cytochromes, as shown by lack of cyanide inhibition in the ferricyanide assay. The purified soluble enzyme did not react in the aerobic assay previously used by others for assay of this enzyme. In contrast to the degradative dihydroorotic dehydrogenases reported by other workers, the biosynthetic dihydroorotic dehydrogenase of E. coli did not link to pyridine nucleotides.

Taylor, W. Herman (Portland State College, Portland, Ore.), and G. David Novelli . Enzymes of the pyrimidine pathway in Escherichia coli . I. Synthesis by cells and spheroplasts. J. Bacteriol. 88: 99–104. 1964.—Upon release from repression, cells and spheroplasts of two mutants of Escherichia coli efficiently synthesized aspartate transcarbamylase and ornithine transcarbamylase, whereas only cells synthesized dihydroorotic dehydrogenase. Ethylenediaminetetraacetate treatment and sucrose incubation of cells were found to be responsible for the loss of dihydroorotic dehydrogenase synthesis. Spheroplasts required the addition of amino acids and an energy source for the synthesis of aspartate transcarbamylase. Uracil repressed synthesis of aspartate transcarbamylase in spheroplasts as well as in cells. Chloramphenicol inhibition and amino acid requirement for increased aspartate transcarbamylase activity in spheroplasts indicated de novo protein synthesis. E. coli 15, R185-482, and E. coli K-12, 496, were used to study the effect of carbon source and stimulation by orotate and dihydroorotate on synthesis of dihydroorotic dehydrogenase. Only E. coli 15, R185-482, showed any stimulation of dihydroorotic dehydrogenase synthesis. When glucose was the carbon source, orotate but not dihydroorotate stimulated; with glycerol as carbon source, dihydroorotate stimulated and orotate acted as a repressor. These results are discussed in terms of induction and pyrimidine supply to the cells.

Some of the catalytic properties of the biosynthetic dihydroorotate dehydrogenase purified from an anaerobic bacterium, Lactobacillus bulgaricus , are described. Studies with p -hydroxymercuribenzoate, N -ethylmaleimide, and mercuric chloride showed that sulfhydryl groups are necessary for transfer of electrons from dihydroorotate to a variety of electron acceptors. Protection studies with substrates for the enzyme indicated that free sulfhydryl groups at or near the active center are required for catalytic activity. Evidence is presented for the production of superoxide free radicals during reaction of the enzyme with molecular oxygen. Inhibitor studies with Tiron indicated that reduction of cytochrome c by the enzyme may involve the superoxide free radical as an intermediate. Orotate, one of the substrates for the enzyme, has been found to be a competitive inhibitor for the dihydroorotate site. The K i for orotate as estimated by several techniques is 0.1 mM. The K m for dihydroorotate with ferricyanide as the electron acceptor is estimated to be 0.5 mM.

This paper describes the first detailed study on a dihydroorotate dehydrogenase involved in pyrimidine biosynthesis. In most organisms the enzyme is membrane-bound; however, a soluble dihydroorotate dehydrogenase was produced in relatively high levels when the anaerobe, Lactobacillus bulgaricus , was released from repression. The enzyme was purified 213-fold over derepressed levels with a 39% recovery of enzyme units. The enzyme showed only one minor protein contaminant when analyzed by polyacrylamide electrophoresis. It was characterized as a flavoprotein containing only flavine mononucleotide as the prosthetic group. Molecular weight estimations by gel filtration gave a value of approximately 55,000, which is one-half that of the degradative enzyme described by others. During aerobic oxidation of dihydroorotate, the rates of oxygen consumption, orotate formation, and hydrogen peroxide formation were equal, as would be expected in a flavoprotein-catalyzed reaction. The enzymatic activity with ferricyanide as acceptor was optimum around p H 7.7. The stimulation of enzymatic activity over a wide p H range by ammonium sulfate was attributed to an effect on the maximum velocity of the reaction. As analyzed by polyacrylamide electrophoresis, inactivation of the enzyme by visible light resulted in the appearance of a second protein band with lowered specific activity. The purified enzyme used redox dyes, oxygen, or cytochrome c as electron acceptors but was not active with pyridine nucleotides. Flavine adenine dinucleotide has been implicated at the active site for pyridine nucleotide reduction in the degradative enzyme. The biosynthetic enzyme lacks this flavine and the associated activity.