Katherine C. Brewer

The effects of diabetic retinopathy stage and light flicker on inner retinal oxygen extraction fraction

Purpose We determined the effects of light flicker and diabetic retinopathy (DR) stage on retinal vascular diameter (D), oxygen saturation (SO2), and inner retinal oxygen extraction fraction (OEF). Methods Subjects were categorized as nondiabetic control (NC, n = 42), diabetic with no clinical DR (NDR; n = 32), nonproliferative DR (NPDR; n = 42), or proliferative DR (PDR; n = 14). Our customized optical imaging system simultaneously measured arterial and venous D (DA, DV) and SO2 (SO2A, SO2V) before and during light flicker. Inner retinal OEF was derived from SO2 values. Light flicker–induced ratios of metrics (DAR, DVR, SO2AR, SO2VR, OEFR) were calculated. Results Arterial D was larger in NPDR compared to NC (P = 0.01) and PDR (P = 0.002), whereas DV was similar among groups (P ≥ 0.16). Light flicker increased DA and DV (P ≤ 0.004), but DAR and DVR were similar among groups (P ≥ 0.09). Arterial SO2 was higher in all groups compared to NC (P ≤ 0.02) and higher in PDR compared to NDR and NPDR (P<0.001). Arterial SO2 did not change with light flicker (P ≥ 0.1). Venous SO2 was higher in NPDR and PDR compared to NC and NDR (P ≤ 0.02). Light flicker increased SO2V in NC, NDR, and PDR (P ≤ 0.003), and SO2VR was lower in NPDR compared to NC and NDR (P ≤ 0.05). Inner retinal OEF was lower in NPDR compared to NDR and PDR (P ≤ 0.02). Light flicker decreased OEF (P ≤ 0.03), but OEFR was greater in NPDR compared to NC and NDR (P ≤ 0.03). Conclusions The findings of alterations in retinal D, SO2, OEF, and their light flicker–induced responses at stages of DR may be useful to elucidate the pathophysiology of DR.

Association of externalizing religious and spiritual beliefs on stage of colon cancer diagnosis among black and white multicenter urban patient populations: Externalizing Beliefs and Cancer Stage

This study explores whether externalizing religious and spiritual beliefs is associated with advanced‐stage colon cancer at initial oncology presentation and whether this association is stronger for blacks than for whites.

Inner Retinal Oxygen Delivery, Metabolism, and Extraction Fraction in Ins2Akita Diabetic Mice

Purpose Retinal nonperfusion and hypoxia are important factors in human diabetic retinopathy, and these presumably inhibit energy production and lead to cell death. The purpose of this study was to elucidate the effect of diabetes on inner retinal oxygen delivery and metabolism in a mouse model of diabetes. Methods Phosphorescence lifetime and blood flow imaging were performed in spontaneously diabetic Ins2Akita (n = 22) and nondiabetic (n = 22) mice at 12 and 24 weeks of age to measure retinal arterial (O2A) and venous (O2V) oxygen contents and total retinal blood flow (F). Inner retinal oxygen delivery (DO2) and metabolism (MO2) were calculated as F ∗ O2A and F ∗ (O2A − O2V), respectively. Oxygen extraction fraction (OEF), which equals MO2/DO2, was calculated. Results DO2 at 12 weeks were 112 ± 40 and 97 ± 29 nL O2/min in nondiabetic and diabetic mice, respectively (NS), and 148 ± 31 and 85 ± 37 nL O2/min at 24 weeks, respectively (P < 0.001). MO2 were 65 ± 31 and 66 ± 27 nL O2/min in nondiabetic and diabetic mice at 12 weeks, respectively, and 79 ± 14 and 54 ± 28 nL O2/min at 24 weeks, respectively (main effects = NS). At 12 weeks OEF were 0.57 ± 0.17 and 0.67 ± 0.09 in nondiabetic and diabetic mice, respectively, and 0.54 ± 0.07 and 0.63 ± 0.08 at 24 weeks, respectively (main effect of diabetes: P < 0.01). Conclusions Inner retinal MO2 was maintained in diabetic Akita mice indicating that elevation of the OEF adequately compensated for reduced DO2 and prevented oxidative metabolism from being limited by hypoxia.

Abstract 1768: Racial/ethnic differences in endometrioid endometrial cancer survival among cases identified through the National Cancer Database

OBJECTIVES: Past research suggests that at the local level, Non-Hispanic whites (NHW) have better survival when diagnosed with endometrioid endometrial cancer (EEC) than non-Hispanic blacks (NHB), Hispanics, and American Indians; however, little is known about survival differences at a national level and among other minorities. This study examined whether racial and ethnic differences in 5-year survival are present in U.S. women (NHW, NHB, Hispanics, non-Hispanic Asians (NHA), non-Hispanic Pacific Islanders/Hawaiians (NHPI), non-Hispanic American Indians/Aleutians or Eskimos (NHAI/AN) and non-Hispanics Others (NHO). METHODS: EEC cases from the National Cancer Database were analyzed to evaluate racial/ethnic differences in 5-year survival among women diagnosed with EEC between 1998 and 2007. Chi-Square test was used to examine whether differences in demographic, clinical, institutional, and treatment variables varied by race/ethnicity. Multivariable Cox proportional hazard regression models were fit to estimate the adjusted hazard ratio (HR) and 95% confidence interval (95% CI) between race/ethnicity and survival. RESULTS: A total of 178,310 women were diagnosed with EEC between 1998 and 2007. Of these; 74.8% were NHW, 8.3% were NHB, 13.9% were Hispanic, 1.8% were NHA, 0.2% were NHPI, 0.2% were NHAI/AN and 0.8% were NHO. Adjusting for covariates, NHB (HR = 1.29; 95%CI 1.24-1.34) and NHPI (HR = 1.59; 95%CI 1.50-1.67) had poorer survival than NHW. Yet results show that NHA (HR = 0.83; 95%CI 0.74-0.92) and NHO (HR = 0.81; 95%CI 0.69-0.94) had a better survival when compared to NHW. No survival differences were detected between Hispanics, NHAI/AN and NHW. CONCLUSIONS: Results identify racial/ethnic differences in 5-year survival among women diagnosed with EEC cancer in the U.S. between 1998 and 2007. NHA and NHO had a better and NHB and NHPI had a poorer survival when compared to NHW. Citation Format: Anna B. Beckmeyer-Borowko, Caryn E. Peterson, Katherine C. Brewer, Mary O. Otoo, Faith G. Davis, Kent F. Hoskins, Charlotte E. Joslin. Racial/ethnic differences in endometrioid endometrial cancer survival among cases identified through the National Cancer Database. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1768.