The association of neighborhood context with health outcomes among ethnic minority breast cancer survivors.

While individual-level determinants of health, such as education and income, have been well documented among breast cancer survivors, little is known about the role of neighborhood context on survivorship outcomes among this population. The present study examined the association of neighborhood stress with multiple health outcomes among ethnic minority breast cancer survivors (BCS). A mixed-methods approach was used to recruit 320 African-American and Hispanic BCS who were 26-89 years and lived in metropolitan Los Angeles, CA. Neighborhood stress was assessed by six items taken from the Life Stress Scale. Health outcomes included (1) self-rated health, measured by the Short-Form-36 Health Survey, (2) number of comorbidities (0-14), (3) depressive symptoms, assessed by the Center for Epidemiological Studies-Depression scale, and (4) psychological difficulties. Greater neighborhood stress was significantly associated with poorer self-reported health (adjusted ß = -.22, 95% confidence interval [CI] -.40, -.05), greater number of comorbidities (adjusted risk ratio = .19, 95% CI .07, .30), more depressive symptoms (adjusted ß = .10, 95% CI .06, .15), and a higher likelihood of psychological difficulties (adjusted odds ratio = 2.28, 95% CI 1.51, 3.45) among ethnic minority BCS. These findings underscored the importance of taking neighborhood context into account in examining the determinants of health, survivorship, and quality of life outcomes among cancer patients. Our findings may inform population health, health services, and interventions addressing neighborhood and individual-level factors to promote post treatment health and survivorship outcomes as well as to identify high-risk patients, especially among medically vulnerable communities.

Role of blood and vascular smooth muscle in the vasoactivity of nitrite.

Recent evidence from humans and rats indicates that nitrite is a vasodilator under hypoxic conditions by reacting with metal-containing proteins to produce nitric oxide (NO). We tested the hypothesis that near-physiological concentrations of nitrite would produce vasodilation in a hypoxia- and concentration-dependent manner in the hind limb of sheep. Anesthetized sheep were instrumented to measure arterial blood pressure and femoral blood flows continuously in both hind limbs. Nitrite was infused into one femoral artery to raise the nitrite concentration in the femoral vein by 10 to 15-fold while the sheep breathed 50%, 14% or 12% oxygen in inspired air. In contrast to reports in humans and rats, the nitrite infusion had no measurable effect on mean femoral blood flows or vascular conductances, regardless of inspired O2 levels. In vitro experiments showed no significant difference in the release of NO from nitrite in sheep and human red blood cells. Further experiments demonstrated nitrite is converted to NO in rat artery homogenates faster than sheep arteries, and that this source of NO production is attenuated in the presence of a heme oxidizer. Finally, western blots indicate that concentrations of the heme-containing protein cytoglobin, but not myoglobin, are markedly lower in sheep arteries compared with rats. Overall, the results demonstrate that nitrite is not a physiological vasodilator in sheep. This is likely due to a lack of conversion of nitrite to NO within the vascular smooth muscle, perhaps due to deficient amounts of the heme-containing protein cytoglobin.