Browsing by Author "Nitikorn Poriswanish"

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    Pathology of fatal diffuse brain injury in severe non-penetrating head trauma
    (2021-08-01) Kodchakan Rungruangsak; Nitikorn Poriswanish; Siriraj Hospital; Thailand Ministry of Public Health
    Traumatic brain injury (TBI) is recognised as a serious global public health problem that imposes a heavy socioeconomic burden on society. The vast majority of cases result from road traffic accidents and falls, and the injuries are mainly attributed to velocity-related mechanisms. Lethal cases are mostly found to suffer from severe diffuse brain injuries (DBI), comprising diffuse vascular injury, diffuse axonal injury (DAI), generalized cerebral edema and ischemic-hypoxic injury. Coup and contrecoup brain contusions may also occur. This study set out to describe the pathological findings of severe DBI in terms of survival times and Abbreviated Injury Scale (AIS) severity scores. The autopsy data from 2 recent years (2018 and 2019) were reviewed to recruit over 800 cases presenting with severe head injuries. Many demographic characteristics of TBI were identified (for example, causes, victim genders and victim ages). These were revealed to be like those previously reported in the literature, confirming that there are shared risk factors across the globe. The hallmarks of severe TBI—such as a unimodal survival distribution and a period for detecting DAI via conventional staining—were also evident, as per previous reports. However, it was noticed that the histopathological detection rates of DAI surged after 72 h, which might be because these injuries are mediated by secondary axotomy. This study also analysed real brain weights to identify the time period for the development of cerebral edema in humans; this period seems to have never been reported. The increment time of cerebral edema reached a peak in 12 h, after which the condition sustained for at least 72 h. This may be a golden period in clinical practice as well as a prognostic factor in forensic medicine.
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    Recombination hotspots in an extended human pseudoautosomal domain predicted from double-strand break maps and characterized by sperm-based crossover analysis
    (2018-10-01) Nitikorn Poriswanish; Rita Neumann; Jon H. Wetton; John Wagstaff; Maarten H.D. Larmuseau; Mark A. Jobling; Celia A. May; University of Leicester; KU Leuven; Faculty of Medicine, Siriraj Hospital, Mahidol University
    © 2018 Poriswanish et al. http://creativecommons.org/licenses/by/4.0/. The human X and Y chromosomes are heteromorphic but share a region of homology at the tips of their short arms, pseudoautosomal region 1 (PAR1), that supports obligate crossover in male meiosis. Although the boundary between pseudoautosomal and sex-specific DNA has traditionally been regarded as conserved among primates, it was recently discovered that the boundary position varies among human males, due to a translocation of ~110 kb from the X to the Y chromosome that creates an extended PAR1 (ePAR). This event has occurred at least twice in human evolution. So far, only limited evidence has been presented to suggest this extension is recombinationally active. Here, we sought direct proof by examining thousands of gametes from each of two ePAR-carrying men, for two subregions chosen on the basis of previously published male X-chromosomal meiotic double-strand break (DSB) maps. Crossover activity comparable to that seen at autosomal hotspots was observed between the X and the ePAR borne on the Y chromosome both at a distal and a proximal site within the 110-kb extension. Other hallmarks of classic recombination hotspots included evidence of transmission distortion and GC-biased gene conversion. We observed good correspondence between the male DSB clusters and historical recombination activity of this region in the X chromosomes of females, as ascertained from linkage disequilibrium analysis; this suggests that this region is similarly primed for crossover in both male and female germlines, although sex-specific differences may also exist. Extensive resequencing and inference of ePAR haplotypes, placed in the framework of the Y phylogeny as ascertained by both Y microsatellites and single nucleotide polymorphisms, allowed us to estimate a minimum rate of crossover over the entire ePAR region of 6-fold greater than genome average, comparable with pedigree estimates of PAR1 activity generally. We conclude ePAR very likely contributes to the critical crossover function of PAR1.