Publications

Tobacco and marijuana use among U.S. young adults is a top public health concern, and racial/ethnic minorities may be at particular risk. Past research examining cultural variables has focused on the individual in relation to the mainstream U.S. culture; however, an individual can also experience within-group stress, or intragroup marginalization. We used the 2014 San Francisco Bay Area Young Adult Health Survey to validate an abbreviated measure of intragroup marginalization and identify associations between intragroup marginalization and tobacco and marijuana use among ethnic minority young adults (N = 1,058). Exploratory factor analysis was conducted to identify factors within the abbreviated scale, and logistic regressions were conducted to examine relationships between intragroup marginalization and tobacco and marijuana use. Two factors emerged from the abbreviated scale. The first factor encompassed items related to belonging and membership, capturing whether individuals experienced marginalization due to not fitting in because of physical appearance or behavior. The second factor encompassed whether individuals shared similar hopes and dreams to their friends and family members. Factor 1 (membership) was associated with increased odds of marijuana use (OR = 1.34, p < .05) and lower odds of using cigars (OR = 0.79, p < .05), controlling for sociodemographic factors. Results suggest that young adults may use marijuana as a means to build connection and belonging to cope with feeling marginalized. Health education programs focused on ethnic minority young adults are needed to help them effectively cope with intragroup marginalization without resorting to marijuana use.

Acute kidney injury (AKI) is a major risk factor for the development of chronic kidney disease (CKD). Persistent oxidative stress and mitochondrial dysfunction are implicated across diverse forms of AKI and in the transition to CKD. In this study, we applied hyperpolarized (HP) C dehydroascorbate (DHA) and C pyruvate magnetic resonance spectroscopy (MRS) to investigate the renal redox capacity and mitochondrial pyruvate dehydrogenase (PDH) activity, respectively, in a murine model of AKI at baseline and 7 days after unilateral ischemia reperfusion injury (IRI). Compared with the contralateral sham-operated kidneys, the kidneys subjected to IRI showed a significant decrease in the HP C vitamin C/(vitamin C + DHA) ratio, consistent with a decrease in redox capacity. The kidneys subjected to IRI also showed a significant decrease in the HP C bicarbonate/pyruvate ratio, consistent with impaired PDH activity. The IRI kidneys showed a significantly higher HP C lactate/pyruvate ratio at day 7 compared with baseline, although the C lactate/pyruvate ratio was not significantly different between the IRI and contralateral sham-operated kidneys at day 7. Arterial spin labeling magnetic resonance imaging (MRI) demonstrated significantly reduced perfusion in the IRI kidneys. Renal tissue analysis showed corresponding increased reactive oxygen species (ROS) and reduced PDH activity in the IRI kidneys. Our results show the feasibility of HP C MRS for the non-invasive assessment of oxidative stress and mitochondrial PDH activity following renal IRI.