Predictors of willingness to participate in HIV vaccine trials among African Americans

African Americans in the United States (U.S.) are disproportionately affected by HIV. Developing an HIV vaccine is an important part of the HIV prevention and treatment toolkit and may help contribute to ending the HIV epidemic. To date, HIV vaccine trials have not engaged representative numbers of African Americans. We evaluated the willingness of African Americans to participate in HIV vaccine trials and identified correlates of willingness to participate (WTP) by surveying African Americans at low- and high-risk of HIV infection in a multi-site, cross-sectional study. We enrolled 1,452 participants; 59% heterosexual women; 21% heterosexual men; 20% men who have sex with men (MSM). Over half of participants (58%) expressed some level of WTP in HIV vaccine trials. Multivariable analyses revealed several variables were positively related to WTP: HIV risk behavior, knowing someone with HIV/AIDS, social support for trial participation, high perception of risk, perceived protection if in a trial, altruism, and greater tolerance for the ambiguous nature of trials (p\u3c0.01). Emphasis on contextual factors related to personal HIV experiences, including knowledge of someone with HIV, and community support for research, may provide effective strategies for engaging African Americans in future HIV vaccine trials

Elevated Diastolic Closing Margin Is Associated with Intraventricular Hemorrhage in Premature Infants.

OBJECTIVE: To determine whether the diastolic closing margin (DCM), defined as diastolic blood pressure minus critical closing pressure, is associated with the development of early severe intraventricular hemorrhage (IVH). STUDY DESIGN: A reanalysis of prospectively collected data was conducted. Premature infants (gestational age 23-31 weeks) receiving mechanical ventilation (n = 185) had ∼1-hour continuous recordings of umbilical arterial blood pressure, middle cerebral artery cerebral blood flow velocity, and PaCO2 during the first week of life. Models using multivariate generalized linear regression and purposeful selection were used to determine associations with severe IVH. RESULTS: Severe IVH (grades 3-4) was observed in 14.6% of the infants. Irrespective of the model used, Apgar score at 5 minutes and DCM were significantly associated with severe IVH. A clinically relevant 5-mm Hg increase in DCM was associated with a 1.83- to 1.89-fold increased odds of developing severe IVH. CONCLUSION: Elevated DCM was associated with severe IVH, consistent with previous animal data showing that IVH is associated with hyperperfusion. Measurement of DCM may be more useful than blood pressure in defining cerebral perfusion in premature infants.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Oxford University Press

Does hypothermia impair cerebrovascular autoregulation in neonates during cardiopulmonary bypass?

BACKGROUND: Autoregulation monitoring has been proposed as a means to identify optimal arterial blood pressure goals during cardiopulmonary bypass, but it has been observed that cerebral blood flow is pressure passive during hypothermic bypass. When neonates cooled during cardiopulmonary bypass are managed with vasodilators and controlled hypotension, it is not clear whether hypothermia or hypotension were the cause of impaired autoregulation. AIM: We sought to measure the effect of both arterial blood pressure and hypothermia on autoregulation in a cohort of infants cooled for bypass, hypothesizing a collinear relationship between hypothermia, hypotension, and dysautoregulation. METHODS: Cardiopulmonary bypass was performed on 72 infants at Texas Children's Hospital during 2015 and 2016 with automated physiologic data capture, including arterial blood pressure, nasopharyngeal temperature, cerebral oximetry, and a cerebral blood volume index derived from near infrared spectroscopy. Cooling to 18°C, 24°C, and 30°C was performed on 33, 12, and 22 subjects, respectively. The hemoglobin volume index was calculated as a moving correlation coefficient between mean arterial blood pressure and the cerebral blood volume index. Positive values of the hemoglobin volume index indicate impaired autoregulation. Relationships between variables were assessed utilizing a generalized estimating equation approach. RESULTS: Hypothermia was associated with hypotension, dysautoregulation, and increased cerebral oximetry. Comparing the baseline temperature of 36°C with 18°C, arterial blood pressure was 44 mm Hg (39-52) vs 25 mm Hg (21-31); the hemoglobin volume index was 0.0 (-0.02 to 0.004) vs 0.5 (0.4-0.7) and cerebral oximetry was 59% (57-61) vs 88% (80-92) (Median, 95% CI of median; P<.0001 for all three associations by linear regression with generalized estimation of equations with data from all temperatures measured). CONCLUSIONS: Arterial blood pressure, temperature, and cerebral autoregulation were collinear in this cohort. The conclusion that hypothermia causes impaired autoregulation is thus confounded. The effect of temperature on autoregulation should be delineated before clinical deployment of autoregulation monitors to prevent erroneous determination of optimal arterial blood pressure. Showing the effect of temperature on autoregulation will require a normotensive hypothermic model

The Effects of Cognitive Behavioral Healthy Lifestyle Intervention for Cardiovascular Risk Reduction in Posttraumatic Stress Disorder

Considerable research has indicated strong associations between posttraumatic stress and cardiovascular disease (CVD) risk. Individuals with posttraumatic stress disorder (PTSD) tend to show patterns of elevated CVD risk earlier in life than in the general population. The need for developing effective interventions for CVD risk-reduction in PTSD is increasingly evident. In comparison to the cumulative evidence concerning elevated CVD risk in PTSD, relatively little research has addressed CVD risk reduction in this population. Adjunctive treatments, such as health behavior interventions, may be necessary as supplements to traditional psychotherapy for PTSD in order to reduce CVD risks. The objective of the proposed project is to examine the effects of a healthy lifestyle intervention that addresses multiple CVD-related heath behaviors among civilian adults across genders (ages 18+), who evidence PTSD and CVD risk at baseline. We will assess the intervention impact on both subjective and objective indices of health behaviors, cardiovascular risks and CVD markers over a one-year timeframe. The healthy lifestyle intervention addresses unique aspects of PTSD symptom presentation that serve as barriers to healthy behaviors (e.g., avoidance of physiological arousal/activation, viewing extra body weight as protection against abuse, nightmares/sleep disruption, and cognitive responses to stress), while encouraging healthy lifestyle changes. The primary goal of the present study is to examine whether, compared to a usual care psychotherapy control condition, utilizing the healthy lifestyle intervention as an adjunct to psychotherapy will result in significantly reduced CVD risks and improved CVD markers among civilian adults with PTSD and elevated CVD risks. Therefore, participants will be randomly assigned to either a usual care psychotherapy-only control condition or a usual care psychotherapy plus healthy lifestyle intervention condition. Outcomes will be assessed at post-intervention (12 weeks), as well as 6- month and 12-month time points for follow-up evaluation

Development of a Health Behavior Intervention for Adults with PTSD

Post-traumatic stress disorder (PTSD), is a disorder of extreme stress/anxiety responses to a psychologically traumatic experience, has been associated with significantly greater incidence of heart disease and prevalence of metabolic syndrome. This higher risk for cardiovascular disease (CVD) in PTSD appears to be, in part, due to difficulties maintaining healthy lifestyles (e.g., weight management through healthy diet and regular physical activity, adequate sleep) and coping with daily stressors. The need for developing effective CVD prevention programs for adults with PTSD is increasingly evident. Therefore additional research is needed to examine programs that may reduce health risk behaviours and prevent early onset of CVD. The present project is a pilot study to examine whether a treatment program focused on healthy lifestyle behaviours (physical activity, good nutrition, sleep hygiene) and stress management will be associated with reductions in the levels of CVD risk variables (e.g., body weight, lipids, blood pressure) for adults with chronic PTSD and least one of the targeted health risks.This presentation illustrates the development of the intervention program, and the design of the study measurement. Results of preliminary cases will assist in determining whether targeting health behaviours as a novel component of PTSD treatment aids in reducing CVD risk

Cardiovascular regulation, baroreceptor sensitivity, and perceived pain in type 1 diabetes mellitus

In light of well-established cardiovascular- and pain-regulatory dysfunction in type I diabetes mellitus, relationships among pain regulatory mechanisms and cardiovascular regulation are of particular interest. The present study examined differences for individuals with type 1 diabetes mellitus in terms of perceived pain, and cardiovascular measures (blood pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance) at rest and during responses to two stressful behavioral (cold pressor test and mental arithmetic) tasks, as well the relationship between pain and cardiovascular regulation. It has been hypothesized that baroreceptor reflex function plays a role in the relationship between pain and cardiovascular regulation. Therefore, the contribution of baroreceptor sensitivity (derived during infusions of phenylephrine and nitroprusside) to the relationships between pain perception and cardiovascular reactivity was investigated in 32 subjects with long term type 1 diabetes mellitus, ( ≥ 8 years duration) and 22 non diabetic controls with no first degree relatives with diabetes (mean +/- SD age 35 +/- 8 years). The type 1 diabetes subjects were asymptomatic or displayed minimal evidence of sensory neuropathy, and glycemia was well controlled (mean +/- SD HbA1c = 7.2 +/- 2.2).Blood pressure reactivity to the cold pressor test was predictive of perceived pain in control subjects, but not subjects with type 1 diabetes mellitus. Heart rate reactivity to the cold pressor was also predictive of pain. During mental arithmetic, heart rate and cardiac output reactivity were predictive of pain among control subjects, but not subjects with type 1 diabetes. Baroreceptor sensitivity derived during phenylephrine (pressor response) was predictive of pain in controls only, but baroreceptor sensitivity derived during nitroprusside was predictive of pain in both groups. Baroreceptor sensitivity (phenylephrine) was predictive of blood pressure reactivity among controls only. Furthermore, controlling for the effects of baroreceptor sensitivity negated the relationship between cold pressor blood pressure reactivity and pain in controls and between cold pressor heart rate reactivity and pain. Controlling for baroreceptor sensitivity did not influence the relationships between pain and mental arithmetic heart rate and cardiac output reactivity. It is concluded that baroreceptor feedback is a critical factor in cardiovascular and sensory regulation, and that these relationships are disrupted in type 1 diabetes mellitus. It is determined that duration of diabetes and psychological regulation are factors that influence baroreceptor relationships to cardiovascular- and pain-regulation

EVALUATION OF A BRIEF QUESTIONNAIRE FOR ASSESSING BARRIERS TO RESEARCH PARTICIPATION

Racial minority groups are often underrepresented in biobehavioral research. Mistrust stemming from historic abuses of minority research participants is one explanation for this problem. Although mistrust and other variables affect dispositions toward research, brief, quantitative measures of these factors have not been available to researchers in assessing potential recruitment barriers. The present paper is a description and psychometric examination of the Barriers to Research Participation Questionnaire (BRPQ), a new survey designed to assess five factors that affect research participation (religious beliefs, mistrust, health-related fears/beliefs, role overload/ time demands, and perceived personal and community benefits). Good model-fit for the proposed five-factor structure and good testretest reliability were observed among African American undergraduate men and women at an urban, primarily African American university. The BRPQ appears to be a reliable and valid tool for researchers to use in identifying barriers to recruiting African American participants