Effect of neighborhood and individual-level socioeconomic factors on breast cancer screening adherence in a multi-ethnic study.

BACKGROUND: Although mammography can significantly reduce breast cancer mortality, many women do not receive their annual breast cancer screening. Differences in screening adherence exist by race/ethnicity, socioeconomic status (SES), and insurance status. However, more detailed investigations into the impact of neighborhood disadvantage and access to resources on screening adherence are lacking. METHODS: We comprehensively examined the effect of individual social, economic, and demographic factors (n = 34 variables), as well as neighborhood level SES (nSES) indicators (n = 10 variables) on breast cancer screening adherence across a multi-ethnic population (n = 472). In this cross-sectional study, participants were surveyed from 2017 to 2018. The data was analyzed using univariate regression and LASSO for variable reduction. Significant predictors were carried forward into final multivariable mixed-effect logistic regression models where odds ratios (OR), 95% confidence intervals and p-values were reported. RESULTS: Nineteen percent of participants were non-adherent to breast screening guidelines. Race/ethnicity was not associated with adherence; however, increasing age (OR = 0.97, 95%CI = 0.95-0.99, p = 0.01), renting a home (OR = 0.53, 95%CI = 0.30-0.94, p = 0.04), food insecurity (OR 0.46, 95%CI = 0.22-0.94, p = 0.01), and overcrowding (OR = 0.58, 95% CI = 0.32-0.94, p = 0.01) were significantly associated with lower breast cancer screening adherence. CONCLUSION: Socioeconomic indicators at the individual and neighborhood levels impact low breast cancer screening adherence and may help to inform future screening interventions.

New findings on SNP variants of human protein L-isoaspartyl methyltransferase that affect catalytic activity, thermal stability, and aggregation.

Protein L-isoaspartyl methyltransferase (PIMT/PCMT1), a product of the pcmt1 gene, catalyzes repair of abnormal L-isoaspartyl linkages in age-damaged proteins. Pcmt1 knockout mice exhibit a profound neuropathology and die 30-60 days postnatal from an epileptic seizure. Here we characterize four new SNP variants of human PIMT with respect to enzymatic activity, thermal stability, and propensity to aggregation. Under standard assay conditions, L191S, A150V, P174H and A65V showed activity losses of 72%, 64%, 61%, and 11% respectively. By differential scanning fluorimetry, melting temperature deviations were -5.2, -4.5, +0.5, and -3.4°C. SDS-PAGE of purified protein reveal significant aggregation of L191S, A150V, and P174H, but not A65V. We also report new data on three unusual PIMT variants among the 13 recently characterized by our laboratory. A7P and I58V were previously found to have 1.8-2.0 times the activity of WT PIMT in the standard assay; however, upon kinetic analysis, we find both variants exhibit reduced catalytic efficiency (Vmax/Km) due to weak isoaspartyl substrate binding. The near complete loss of activity (<1%) seen in R36C was investigated by comparing activity of two artificial variants. R36K shows 4.6X the activity of R36C, while R36A shows no improvement, suggesting the guanidino nitrogens of the R36 play a key role in binding the methyl donor S-adenosyl-L-methionine (AdoMet). The new findings reported here extend the list of human PIMT variants that may contribute to neurological diseases in the young and the decline of CNS function in the aged.

Polymorphic Variants of Human Protein l-Isoaspartyl Methyltransferase Affect Catalytic Activity, Aggregation, and Thermal Stability: IMPLICATIONS FOR THE ETIOLOGY OF NEUROLOGICAL DISORDERS AND COGNITIVE AGING.

Protein l-isoaspartyl methyltransferase (PIMT/PCMT1), a product of the human pcmt1 gene, catalyzes repair of abnormal l-isoaspartyl linkages in age-damaged proteins. Pcmt1 knock-out mice exhibit a profound neuropathology and die 30-60 days postnatal from an epileptic seizure. Here we express 15 reported variants of human PIMT and characterize them with regard to their enzymatic activity, thermal stability, and propensity to aggregation. One mutation, R36C, renders PIMT completely inactive, whereas two others, A7P and I58V, exhibit activity that is 80-100% higher than wild type. G175R is highly prone to aggregation and has greatly reduced activity. R17S and R17H show markedly enhanced sensitivity to thermal denaturation. Based on previous studies of moderate PIMT variation in humans and mice, we predict that heterozygosity for R36C, G175R, R17S, and R17H will prove detrimental to cognitive function and successful aging, whereas homozygosity (if it ever occurs) will lead to severe neurological problems in the young.