Chromosome-length genome assemblies and cytogenomic analyses of pangolins reveal remarkable chromosome counts and plasticity.

We report the first chromosome-length genome assemblies for three species in the mammalian order Pholidota: the white-bellied, Chinese, and Sunda pangolins. Surprisingly, we observe extraordinary karyotypic plasticity within this order and, in female white-bellied pangolins, the largest number of chromosomes reported in a Laurasiatherian mammal: 2n = 114. We perform the first karyotype analysis of an African pangolin and report a Y-autosome fusion in white-bellied pangolins, resulting in 2n = 113 for males. We employ a novel strategy to confirm the fusion and identify the autosome involved by finding the pseudoautosomal region (PAR) in the female genome assembly and analyzing the 3D contact frequency between PAR sequences and the rest of the genome in male and female white-bellied pangolins. Analyses of genetic variability show that white-bellied pangolins have intermediate levels of genome-wide heterozygosity relative to Chinese and Sunda pangolins, consistent with two moderate declines of historical effective population size. Our results reveal a remarkable feature of pangolin genome biology and highlight the need for further studies of these unique and endangered mammals.

Noncontact laser Doppler imaging in burn depth analysis of the extremities.

The purpose of this study was to determine the accuracy and practical utility of a noncontact laser Doppler imager (PIM-II, Lisca Development AB, Linköping, Sweden) in the estimation of burn depth in the upper and lower extremities. At 48 hours after burn injury, we performed scans of 35 burns in 22 patients and obtained histological samples for burn determination with hematoxylin and eosin and vimentin immunohistochemical staining. Additionally, sequential scans and tissue specimens were obtained on 10 burns at 24, 48, and 72 hours. A statistically significant inverse relationship was noted between burn depth and the laser Doppler perfusion index. Laser Doppler perfusion index values greater than 1.3 predicted a superficial dermal burn with 95% sensitivity and 94% specificity. Superficial dermal burns exhibited increased perfusion in the early burn period. Wounds showed a progressive decline in perfusion and a progressive increase in the depth of injury during a 72-hour period. This study demonstrates the advantage and accuracy of using a noncontact laser Doppler to differentiate deep dermal from superficial partial thickness burns in the extremities.