N. Adam SmithKrista L. KoellerJulia A. ClarkeDaniel T. Ksepka...
29页
查看更多>>摘要：Abstract Of the more than 6,000 members of the most speciose avian clade, Passeriformes (perching birds), only the five species of dippers (Cinclidae, Cinclus) use their wings to swim underwater. Among nonpasserine wing‐propelled divers (alcids, diving petrels, penguins, and plotopterids), convergent evolution of morphological characteristics related to this highly derived method of locomotion have been well‐documented, suggesting that the demands of this behavior exert strong selective pressure. However, despite their unique anatomical attributes, dippers have been the focus of comparatively few studies and potential convergence between dippers and nonpasseriform wing‐propelled divers has not been previously examined. In this study, a suite of characteristics that are shared among many wing‐propelled diving birds were identified and the distribution of those characteristics across representatives of all clades of extant and extinct wing‐propelled divers were evaluated to assess convergence. Putatively convergent characteristics were drawn from a relatively wide range of sources including osteology, myology, endocranial anatomy, integument, and ethology. Comparisons reveal that whereas nonpasseriform wing‐propelled divers do in fact share some anatomical characteristics putatively associated with the biomechanics of underwater “flight”, dippers have evolved this highly derived method of locomotion without converging on the majority of concomitant changes observed in other taxa. Changes in the flight musculature and feathers, reduction of the keratin bounded external nares and an increase in subcutaneous fat are shared with other wing‐propelled diving birds, but endocranial anatomy shows no significant shifts and osteological modifications are limited. Muscular and integumentary novelties may precede skeletal and neuroendocranial morphology in the acquisition of this novel locomotory mode, with implications for understanding potential biases in the fossil record of other such transitions. Thus, dippers represent an example of a highly derived and complex behavioral convergence that is not fully associated with the anatomical changes observed in other wing‐propelled divers, perhaps owing to the relative recency of their divergence from nondiving passeriforms.
查看更多>>摘要：Abstract This article reviews the literature on capillarization of hepatic sinusoids since its discovery in 1963. Liver sinusoidal endothelial cells are uniquely fenestrated and lack an underlying basement membrane. In chronic liver disease, the sinusoids capillarize and transform into systemic capillaries, a process termed capillarization of sinusoids. The histopathology is marked by defenestration, basement membrane formation, and space of Disse fibrogenesis. Capillarized sinusoids compromise the bidirectional exchange of materials between sinusoids and hepatocytes, leading to hepatocellular dysfunction. Sinusoidal capillarization was first described in active cirrhosis of alcoholics in 1963. Since then, it has been found in early and progressive stages of alcoholic hepatic fibrosis before the onset of cirrhosis. The sinusoidal structure is not altered in alcoholic steatosis without fibrosis. Defenestration impairs the ability of the endothelium to filter chylomicron remnants from sinusoids into the Disse's space, contributing to alcohol‐induced postprandial hyperlipidemia and possibly atherosclerosis. Ethanol also modulates the fenestration dynamics in animals. In baboons, chronic alcohol consumption diminishes endothelial porosity in concomitance with hepatic fibrogenesis and in rats defenestrates the endothelium in the absence of fibrosis, and sometimes capillarizes the sinusoids. Acute ethanol ingestion enlarges fenestrations in rats and contracts fenestrations in rabbits. In sinusoidal endothelial cell culture, ethanol elicits fenestration dilation, which is likely related to its interaction with fenestration‐associated cytoskeleton. Ethanol potentiates sinusoidal injury caused by cocaine, acetaminophen or lipopolysaccharide in mice and rats. Understanding ethanol's mechanisms on pathogenesis of sinusoidal capillarization and fenestration dynamics will lead to development of methods to prevent risks for atherosclerosis in alcoholism.
Ellianna H. ZackStephanie M. SmithKenneth D. Angielczyk
18页
查看更多>>摘要：Abstract Captive specimens in museum collections facilitate study of rare taxa, but the lifestyles, diets, and lifespans of captive animals differ from their wild counterparts. Trabecular bone architecture adapts to in vivo forces, and may reflect interspecific variation in ecology and behavior as well as intraspecific variation between captive and wild specimens. We compared trunk vertebrae bone microstructure in captive and wild xenarthran mammals to test the effects of ecology and captivity. We collected μCT scans of the last six presacral vertebrae in 13 fossorial, terrestrial, and suspensorial xenarthran species (body mass: 120?g to 35?kg). For each vertebra, we measured centrum length; bone volume fraction (BV.TV); trabecular number and mean thickness (Tb.Th); global compactness (GC); cross‐sectional area; mean intercept length; star length distribution; and connectivity and connectivity density. Wild specimens have more robust trabeculae, but this varies with species, ecology, and pathology. Wild specimens of fossorial taxa (Dasypus) have more robust trabeculae than captives, but there is no clear difference in bone microstructure between wild and captive specimens of suspensorial taxa (Bradypus, Choloepus), suggesting that locomotor ecology influences the degree to which captivity affects bone microstructure. Captive Tamandua and Myrmecophaga have higher BV.TV, Tb.Th, and GC than their wild counterparts due to captivity‐caused bone pathologies. Our results add to the understanding of variation in mammalian bone microstructure, suggest caution when including captive specimens in bone microstructure research, and indicate the need to better replicate the habitats, diets, and behavior of animals in captivity.
Matthew J. ZdillaNicholas S. NestorBruce M. RothschildH. Wayne Lambert...
43页
查看更多>>摘要：Abstract Cribra orbitalia is a phenomenon with interdisciplinary interest. However, the etiology of cribra orbitalia remains unclear. Recently, the appearance of cribra orbitalia was identified as vascular in nature. This study assessed the relationship between anatomical variation of vasculature, as determined by the presence of meningo‐orbital foramina, and the presence of cribra orbitalia in 178 orbits. Cribra orbitalia was identified in 27.5% (49:178) of orbits (22.7%, 35:154 adult orbits and 58.3%, 14:24 subadult orbits) and meningo‐orbital foramina were identified in 65.8% (100:152) of orbits. Among the 150 total intact adult orbits (i.e., orbital roof and posterior orbits both intact), cribra orbitalia was found in 35 (23.3%). Of these 35 occurrences of cribra orbitalia, 32 (91.4%) had the concurrent finding of a meningo‐orbital foramen. However, in the absence of the meningo‐orbital foramen, cribra orbitalia was only found in three sides out of the total sample of intact orbits (3:150; 2.0%). Fisher's exact test revealed that the presence of cribra orbitalia and the meningo‐orbital foramen were statistically dependent variables (p?=?.0002). Visual evidence corroborated statistical findings—vascular impressions joined cribra orbitalia to meningo‐orbital foramina. This study identifies that individuals who possess a meningo‐orbital foramen are anatomically predisposed to developing cribra orbitalia. Conversely, cribra orbitalia is unlikely to occur in an individual who does not possess a meningo‐orbital foramen. Thus, the antecedent of cribra orbitalia is both vascular and developmental in nature. This report represents an important advancement in the understanding of cribra orbitalia—there is an anatomical predisposition to the development of cribra orbitalia.
查看更多>>摘要：Abstract Effective therapeutics are not available for acute lung injury (ALI) and acute respiratory distress syndrome. Modified Xiaoqinglong decoction (M‐XQL) is reported to effectively treat pneumonia, but the underlying mechanisms are unclear. In this study, the therapeutic effect and mechanism of M‐XQL were examined using a lipopolysaccharide (LPS)‐induced ALI mouse model. The effects of M‐XQL on lung injury, inflammatory responses, and cell apoptosis were analyzed. Additionally, high‐throughput sequencing was performed to evaluate the therapeutic mechanism of M‐XQL. Pretreatment with M‐XQL significantly and dose‐dependently mitigated the pathological changes and upregulation of pulmonary, nitric oxide content and cell apoptosis and serum tumor necrosis factor‐alpha contents in the LPS‐induced ALI mouse model. RNA sequencing analysis revealed that the expression of several arachidonic acid metabolism‐associated genes in the LPS?+?high‐dose M‐XQL group differed from that in the LPS group. In particular, the Cbr2, Cyp4f18, and Cyp2e1 levels were upregulated, whereas the Alox12, Ptges, and Ptges2 levels were downregulated in the LPS?+?high‐dose M‐XQL group. These results suggest that M‐XQL exerts therapeutic effects in ALI mice by regulating arachidonic acid metabolism and exerting anti‐apoptotic and anti‐inflammatory effects. Thus, M‐XQL is a potential agent for the clinical treatment of ALI.
查看更多>>摘要：Abstract The upper extremity posture is characteristic of each Carnegie stage (CS), particularly between CS18 and CS23. Morphogenesis of the shoulder joint complex largely contributes to posture, although the exact position of the shoulder joints has not been described. In the present study, the position of the upper arm was first quantitatively measured, and the contribution of the position of the shoulder girdle, including the scapula and glenohumeral (GH) joint, was then evaluated. Twenty‐nine human fetal specimens from the Kyoto Collection were used in this study. The morphogenesis and three‐dimensional position of the shoulder girdle and humerus were analyzed using phase‐contrast X‐ray computed tomography and magnetic resonance imaging. Both abduction and flexion of the upper arm displayed a local maximum at CS20. Abduction gradually decreased until the middle fetal period, which was a prominent feature. Flexion was less than 90° at the local maximum, which was discrepant between appearance and measurement value in our study. The scapular body exhibited a unique position, being oriented internally and in the upward direction, with the glenoid cavity oriented cranially and ventrally. However, this unique scapular position had little effect on the upper arm posture because the angle of the scapula on the thorax was canceled as the angle of the GH joint had changed to a mirror image of that angle. Our present study suggested that measuring the angle of the scapula on the thorax and that of the GH joint using sonography leads to improved staging of the human embryo.
查看更多>>摘要：Abstract Estimation of stature from footprint lengths is a common prediction in forensic cases and in paleoanthropology upon the discovery of fossil footprints. Many studies, which have estimated stature from footprints, generally use a “one‐size‐fits‐all” approach that usually involves applying a known ratio of foot length to total stature to do so, although this method has fallen out of practice in forensic cases in recent years but is still commonly used for fossil trace evidence. Yet, we know that substrate and speed can change the dimensions of a footprint, so why are these “one‐size‐fits‐all” approaches still used today? We tested footprint production across different substrates at a walk, a fast walk, and a jog. We calculated how accurately footprint dimensions were impressed between these different conditions and identified sources of error in footprint lengths, and the percentage changes of how significantly a footprint can change in length between different conditions. We provide a table with different ratios that we encourage practitioners/field scientists to refer to and use when estimating stature from footprints, with respect to the substrate on which the footprint was created and the speed at which it was created. We actively encourage researchers to add the ratios by testing more substrates so that in the future stature can be more accurately estimated, thus aiding the paleoanthropological community, but also forensic investigations by statistically highlighting how different conditions can affect trace dimensions.
James C. WilliamsVictor Hugo CanelaSharon B. BledsoeElaine M. Worcester...
11页
查看更多>>摘要：Abstract Calcium oxalate (CaOx) stones can grow attached to the renal papillary calcification known as Randall's plaque. Although stone growth on Randall's plaque is a common phenomenon, this mechanism of stone formation is still poorly understood. The objective of this study was to investigate the microenvironment of mature Randall's plaque, explore its molecular composition and differentiate plaque from CaOx overgrowth using multimodal imaging on demineralized stone sections. Fluorescence imaging showed consistent differences in autofluorescence patterns between Randall's plaque and calcium oxalate overgrowth regions. Second harmonic generation imaging established the presence of collagen only in regions of decalcified Randall's plaque but not in regions of CaOx overgrowth matrix. Surprisingly, in these stone sections we observed cell nuclei with preserved morphology within regions of mature Randall's plaque. These conserved cells had variable expression of vimentin and CD45. The presence of nuclei in mature plaque indicates that mineralization is not necessarily associated with cell death. The markers identified suggest that some of the entrapped cells may be undergoing dedifferentiation or could emanate from a mesenchymal or immune origin. We propose that entrapped cells may play an important role in the growth and maintenance of Randall's plaque. Further characterization of these cells and thorough analyses of the mineralized stone forming renal papilla will be fundamental in understanding the pathogenesis of Randall's plaque and CaOx stone formation.
查看更多>>摘要：Abstract Fishes exhibit a dynamic array of reproductive diversity. Among the various forms of reproduction, internal fertilization has evolved at least 13 times and has been observed in 2–3% of teleost species, half of which are marine. Internal fertilization has led to the evolution of male intromittent organs to aid in sperm transfer during copulation. The intromittent organs of poeciliids have been widely investigated, but little research has focused on the intromittent organs of marine fishes. The surfperches are internally fertilizing, viviparous fishes with a ventrally located papilla. In this article, the external morphology of 19 Embiotocidae species was examined. Additionally, paraffin histology was used to investigate the walleye surfperch (Hyperprosopon argenteum), black perch (Embiotoca jacksoni), and dwarf perch (Micrometrus minimus) papilla to aid in the identification of tissue composition to determine its function. External morphology was documented via macro photography and males were dissected to observe the relationship between the testes, spermatic duct, and papilla. We provide histological evidence that the urogenital papilla is directly connected to the spermatic duct and testis and likely involved in spermatozeugmata transfer. Our research also determined that the papillae were composed of both urinary and reproductive tissues, thus we propose the papilla be referred to as a urogenital papilla. Our study contributes to an overall understanding of intromittent organs of marine fishes, particularly in the surfperches, which has not been previously documented.
NSTL
Wiley