Browsing by Author "Tsongalis, Gregory J."

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    Alpha-synuclein (SNCA) polymorphisms exert protective effects on memory after mild traumatic brain injury
    (Elsevier, 2016-09-06) Shee, Kevin; Lucas, Alexandra; Flashman, Laura A.; Nho, Kwangsik; Tsongalis, Gregory J.; McDonald, Brenna C.; Saykin, Andrew J.; McAllister, Thomas W.; Rhodes, C. Harker; Psychiatry, School of Medicine
    Problems with attention and short-term learning and memory are commonly reported after mild traumatic brain injury (mTBI). Due to the known relationships between α-synuclein (SNCA), dopaminergic transmission, and neurologic deficits, we hypothesized that SNCA polymorphisms might be associated with cognitive outcome after mTBI. A cohort of 91 mTBI patients one month after injury and 86 healthy controls completed a series of cognitive tests assessing baseline intellectual function, attentional function, and memory, and was genotyped at 13 common single nucleotide polymorphisms (SNPs) in the SNCA gene. Significant differences in two memory measures (p = 0.001 and 0.002), but not baseline intellectual function or attentional function tasks, were found between the mTBI group and controls. A highly significant protective association between memory performance and SNCA promoter SNP rs1372525 was observed in the mTBI patients (p = 0.006 and 0.029 for the long and short delay conditions of the California Verbal Learning Tests, respectively), where the presence of at least one copy of the A (minor) allele was protective after mTBI. These results may help elucidate the pathophysiology of cognitive alterations after mTBI, and thus warrant further investigation.
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    Longitudinal assessment of cognitive changes associated with adjuvant treatment for breast cancer: the impact of APOE and smoking
    (Wiley Blackwell (John Wiley & Sons), 2014-12) Ahles, Tim A.; Li, Yuelin; McDonald, Brenna C.; Schwartz, Gary N.; Kaufman, Peter A.; Tsongalis, Gregory J.; Moore, Jason H.; Saykin, Andrew J.; Department of Radiology and Imaging Sciences, IU School of Medicine
    PURPOSE: This study examined the association of post-treatment changes in cognitive performance, apolipoprotein E (APOE), and smoking in breast cancer patients treated with adjuvant therapy. PARTICIPANTS AND METHODS: Breast cancer patients treated with chemotherapy (N = 55, age = 51.9 ± 7.1, education = 15.7 ± 2.6) were evaluated with a battery of neuropsychological tests prior to chemotherapy and at 1, 6, and 18 months post-chemotherapy. Matched groups of breast cancer patients not exposed to chemotherapy (N = 68, age = 56.8 ± 8.3, education = 14.8 ± 2.2) and healthy controls (N = 43, age = 53.0 ± 10.1, education = 15.2 ± 2.6) were evaluated at similar intervals. APOE epsilon 4 carrier status (APOE4+) and smoking history were also evaluated. RESULTS: The detrimental effect of APOE4+ genotype on post-treatment cognitive functioning was moderated by smoking history, that is, patients without a smoking history had significantly lower performance on measures of processing speed and working memory compared with those with a smoking history and healthy controls. Exploratory analyses revealed that APOE4+ patients without a smoking history who were exposed to chemotherapy showed a decline in performance in processing speed, compared with patients with a smoking history. A similar but less pronounced pattern was seen in the no chemotherapy group (primarily endocrine treatment). For working memory, the APOE4+ by smoking interaction was observed in the no chemotherapy group only. CONCLUSIONS: The association between APOE status, breast cancer treatment, and cognitive functioning was moderated by smoking history suggesting that both chemotherapy and endocrine therapy interact with APOE status and smoking to influence cognition. A putative mechanism is that smoking corrects a deficit in nicotinic receptor functioning and dopamine levels in APOE4+ individuals.