Postmortem changes in brain cell structure: a review

Brain cell structure is a key determinant of neural function that is frequently altered in neurobiological disorders. Following the global loss of blood flow to the brain that initiates the postmortem interval (PMI), cells rapidly become depleted of energy and begin to decompose. To ensure that our methods for studying the brain using autopsy tissue are robust and reproducible, there is a critical need to delineate the expected changes in brain cell morphometry during the PMI. We searched multiple databases to identify studies measuring the effects of PMI on the morphometry (i.e. external dimensions) of brain cells. We screened 2119 abstracts, 361 full texts, and included 172 studies. Mechanistically, fluid shifts causing cell volume alterations and vacuolization are an early event in the PMI, while the loss of the ability to visualize cell membranes altogether is a later event. Decomposition rates are highly heterogenous and depend on the methods for visualization, the structural feature of interest, and modifying variables such as the storage temperature or the species. Geometrically, deformations of cell membranes are common early events that initiate within minutes. On the other hand, topological relationships between cellular features appear to remain intact for more extended periods. Taken together, there is an uncertain period of time, usually ranging from several hours to several days, over which cell membrane structure is progressively lost. This review may be helpful for investigators studying human postmortem brain tissue, wherein the PMI is an unavoidable aspect of the research

Postmortem changes in brain cell structure: a review

Brain cell structure is a key determinant of neural function that is frequently altered in neurobiological disorders. Following the global loss of blood flow to the brain that initiates the postmortem interval (PMI), cells rapidly become depleted of energy and begin to decompose. To ensure that our methods for studying the brain using autopsy tissue are robust and reproducible, there is a critical need to delineate the expected changes in brain cell morphometry during the PMI. We searched multiple databases to identify studies measuring the effects of PMI on the morphometry (i.e. external dimensions) of brain cells. We screened 2119 abstracts, 361 full texts, and included 172 studies. Mechanistically, fluid shifts causing cell volume alterations and vacuolization is an early event in the PMI, while loss of cell membrane visualization altogether is a later event. Decomposition rates are highly heterogenous and depend on the methods for visualization, the structural feature of interest, and modifying variables such as the storage temperature or the species. Geometrically, deformations of cell membranes are common early events that initiate within minutes. On the other hand, topological relationships between cellular features appear to be intact for more extended periods. Taken together, there is an uncertain length of time, usually ranging from several hours to several days, over which cell membrane structure is progressively lost. This review may be helpful for investigators studying human postmortem brain tissue, wherein the PMI is an unavoidable aspect of the research

Confirmatory factor analysis of the Infant Feeding Styles Questionnaire in Latino families

BACKGROUND: Parent feeding practices affect risk of obesity in children. Latino children are at higher risk of obesity than the general population, yet valid measure of feeding practices, one of which is the Infant Feeding Styles Questionnaire (IFSQ), have not been formally validated in Spanish. OBJECTIVE: To validate the IFSQ among Latino families, we conducted confirmatory factor analysis of pressuring, restrictive, and responsive feeding constructs from the IFSQ. DESIGN/METHODS: The IFSQ was administered at the 12-month visit in the Greenlight study, a multi-center cluster randomized trial to prevent obesity. Parents were included if they were of Latino origin (n=303) and completed an English or Spanish language modified IFSQ (without the indulgence construct). Scores from nine sub-constructs of the IFSQ were compared between English and Spanish language versions. We tested reliability with Cronbach’s alpha coefficients and performed confirmatory factor analysis to examine factor loadings and goodness of fit characteristics, modifying constructs to achieve best fit. RESULTS: Of 303 parents completing the IFSQ, 84% were born outside the US, and 74% completed the IFSQ in Spanish. Reliability coefficients ranged from 0.28–0.61 for the laissez-faire sub-constructs and from 0.58–0.83 for the pressuring, restrictive, and responsive sub-constructs. Results for all coefficients were similar between participants responding to an English and Spanish version of the IFSQ. Goodness of fit indices ranged from CFI 0.82–1 and RMSEA 0.00–0.31, and the model performed best in pressuring-soothing (CFI 1.0, RMSEA 0.00) and restrictive-amount (CFI 0.98, RMSEA 0.1) sub-constructs. CONCLUSIONS: In a sample of Latino families, pressuring, restrictive, and responsive constructs performed well. The modified IFSQ in both English and Spanish-speaking Latino families may be used to assess parenting behaviors related to early obesity risk in this at-risk population