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Introduction: Previous research indicates ethnic/race group differences in pain and neurodegenerative diseases. Accounting for socioenvironmental factors reduces ethnic/race group differences in clinical and experimental pain. In the current study sample, we previously reported that in individuals with knee pain, ethnic/race group differences were observed in bilateral temporal lobe thickness, areas of the brain associated with risk for Alzheimer's disease, and related dementias. The purpose of the study was to determine if socioenvironmental factors reduce or account for previously observed ethnic/race group differences and explore if a combined effect of socioenvironmental risk and chronic pain severity on temporal lobe cortices is evident. Methods: Consistent with the prior study, the sample was comprised of 147 adults (95 women, 52 men), 45–85 years of age, who self‐identified as non‐Hispanic Black (n = 72) and non‐Hispanic White (n = 75), with knee pain with/at risk for osteoarthritis. Measures included demographics, health history, pain questionnaires, cognitive screening, body mass index, individual‐ and community‐level socioenvironmental factors (education, income, household size, marital and insurance status, and area deprivation index), and brain imaging. We computed a summative socioenvironmental risk index. Results: Regression analyses showed that with the inclusion of socioenvironmental factors, the model was significant (p <.001), and sociodemographic (ethnic/race) group differences were not significant (p =.118). Additionally, findings revealed an additive stress load pattern indicating thinner temporal lobe cortices with greater socioenvironmental risk and chronic pain severity (p =.048). Implications: Although individual socioenvironmental factors were not independent predictors, when collectively combined in models, ethnic/race group differences in bilateral temporal lobe structures were not replicated. Further, combined socioenvironmental risk factors and higher chronic pain severity were associated with thinner bilateral temporal lobes. [ABSTRACT FROM AUTHOR]

• Transesterification and acetylation of lipopolysaccharide in meningococcal PS results in 3-O-acetyl tetradecanoic acid. • 3-hydroxyl fatty acid methyl ester serves as the marker for LPS quantitation in the meningococcal polysaccharide. • GC-MS provides valuable complimentary tool to monitor the endotoxin content in intermediate and purified polysaccharide. • GC-MS can be used to quantitate LPS in other gram-negative bacteria, lipids and proteins. Bacterial lipopolysaccharide (LPS) responsible for endotoxin effect induces inflammatory reactions. The endotoxins are difficult to separate from the gram-negative polysaccharide (PS) during polysaccharide purification. The most common method to quantify LPS is the limulus amebocyte lysate (LAL) test which interferes with the agents used during PS purification. The gas chromatography-mass spectrometry (GC-MS) provides a suitable alternative by estimating lipid-A chain anchored 3-hydroxy fatty acid methyl ester (FAME) to estimate LPS however, there are no reports of its application in natural polysaccharides used for vaccine preparation. The transesterification of LPS and meningococcal PS yielded primary target 3-O-acetylated myristic acid which was detected by GC-MS and provided quantitative estimation of endotoxin. The GC-MS method was found in agreement with the LAL values showing lower endotoxin content< 10Eu/µg in meningococcal C and Y serogroup polysaccharides in comparison to higher endotoxin 177–523 Eu/µg in meningococcal A, W and X serogroups. The high endotoxin content in purified polysaccharide was attributed to it being detected in its intermediate stage by GC-MS unlike the LAL test. Thus GC-MS serves as a valuable method for endotoxin monitoring and quantitation in gram-negative meningococcal intermediate and purified PS during vaccine preparation. [ABSTRACT FROM AUTHOR]