http://precedings.nature.com/tags/seasonality Recently posted documents tagged with 'seasonality' Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://precedings.nature.com/documents/2969/version/1 Seasonal variation in the occurrence of several classes of cancer has been observed in the past. However, evidence for such trends in adult central nervous system tumors is scant. We have analyzed the monthly occurrence rates of glioblastomas as well as carcinomas metastatic to the brain in 6,154 neurosurgical patients in Toronto selected from the University Health Network neuropathologic database over a seven-year period (July 2001 to June 2008). The electronic repository was representative of the patient population in southern Ontario, and the case accession dates in the database reflected the onset patterns of the selected tumor groups. A modification to Nam’s alternative method to the Roger test was developed to statistically quantify the differences. The results demonstrated significant cyclical occurrence rates of glioblastomas with seasonal peaks in March, June, September and December. Moreover, significant increases in the rates of carcinomas metastatic to the brain were found for January, April and August. Surprisingly, the monthly frequency for the two tumor groups resembled each other in peak/trough topology. Semiquantitative comparison of major histologic features between glioblastomas from a peak (March) and trough (November) month in the seven-year period was performed, revealing differences in the amount of perivascular lymphocytic inflammation. This novel observation may have profound implications for the understanding of the biology of adult central nervous system tumors. http://precedings.nature.com/documents/2969/version/1 Tue, 24 Mar 2009 13:06:50 UTC Seasonal patterns of presentation in primary malignant brain tumors and metastases based on a retrospective neuropathologic database hdl:10101/npre.2009.2969.1 2009-03-24 Tim-Rasmus Kiehl Nature Precedings 2009-03-24T13:06:50Z Manuscript Cancer Neuroscience Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/2259/version/1 Several findings suggest seasonal variations in the serotonin (5-HT) system. We sought evidence for seasonal variation in the serotonin transporter (5-HTT). We found that length of daylight time in minutes correlates negatively with 5-HTT binding in the putamen and the caudate, with a similar tendency in the thalamus, but no such association in the midbrain. In the putamen, an anatomical region with a dense serotonin innervation that is implicated in processing of aversive stimuli, we found a significant gene*daylight effect with a negative correlation between the 5-HTT binding and daylight time in carriers of the short 5-HTTLPR allele, but not in carriers of the long allele. The neurobiological endophenotype identified here directly links activation studies, showing responses on the neural circuit level, with dynamic changes in transporter expression measured in vivo. http://precedings.nature.com/documents/2259/version/1 Wed, 10 Sep 2008 22:59:42 UTC Seasonal changes in brain serotonin transporter binding in short 5-HTTLPR-allele carriers but not in long-allele homozygotes hdl:10101/npre.2008.2259.1 2008-09-10 Jan Kalbitzer Nature Precedings 2008-09-10T22:59:42Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/