Evaluation of the Effects of Power-Frequency Magnetic Field Exposure on B-Cell Differentiation From Human Hematopoietic Stem/Progenitor Cells

The causal relationship between exposure to power-frequency magnetic fields (MFs) and childhood leukemia has long been controversial. The most common type of childhood leukemia is acute B-lymphoblastic leukemia caused by abnormal proliferation of B cells in the early differentiation process. Here, we focused on B-cell early differentiation and aimed to evaluate the effects of exposing cells to power-frequency MF. First, we optimized an in vitro differentiation protocol of human hematopoietic stem/progenitor cells (HSPCs) to B-cell lineages. Following validation of the responsiveness of the protocol to additional stimulations and the uniformity of the experimental conditions, human HSPCs were continuously exposed to 300 mT of 50 Hz MF for 35 days of the differentiation process. These experiments were performed in a blinded manner. The percentages of myeloid or lymphoid cells and their degree of differentiation from pro-B to immature-B cells in the MF-exposed group showed no significant changes compared with those in the control group. Furthermore, the expression levels of recombination-activating gene (RAG)1 and RAG2 in the B cells were also similar to those in the control group. These results indicate that exposure to 50 Hz MF at 300 mT does not affect the human B-cell early differentiation from HSPCs. © 2023 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society.     

早期伤口切开对血循毒蛇咬伤患者预后的影响

目的探讨血循毒类毒蛇咬伤患者早期伤口切开对预后的影响。方法回顾性分析我院2011年3月~2014年3月诊治的血循毒类毒蛇咬伤患者223例的临床资料,总结并比较其临床特点及预后。结果本组患者轻度肿胀97例中,伤后12h内切开21例,未溃疡12例,Ⅰ°溃疡7例,Ⅱ°溃疡2例;晚期切开或未切开76例,未溃疡15例,Ⅰ°溃疡41例,Ⅱ°溃疡16例,Ⅲ°溃疡4例。中度肿胀患者85例中,伤后12h内切开32例,未溃疡8例,Ⅰ°溃疡21例,Ⅱ°溃疡2例,Ⅲ°溃疡1例;晚期切开或未切开53例,未溃疡6例,Ⅰ°溃疡16例,Ⅱ°溃疡24例,Ⅲ°溃疡7例。重度肿胀患者41例中,伤后12h内切开17例,Ⅰ°溃疡11例,Ⅱ°溃疡4例,Ⅲ°溃疡2例;晚期切开或未切开24例,Ⅰ°溃疡2例,Ⅱ°溃疡6例,Ⅲ°溃疡16例。在蛇伤后12h内切开的患者坏死溃疡的形成、肿胀程度的改善均明显优于晚期切开或未切开的患者,差异有显著统计学意义(P0.05)。结论随着患者凝血功能的改善,早期伤口切开对血循毒类毒蛇伤患者局部伤口状况有较好的改善作用。     

广西田东雾云洞更新世脊椎动物群

发现于广西田东雾云洞之脊椎动物化石有9目24科44属种,根据动物群的组成分析并结合地貌特征判断,其时代为中更新世或晚更新世早期。根据动物习性分析,其生存的环境为热带-亚热带温暖湿润的环境。     

Different Functional and Structural Properties of Lactate Dehydrogenase Isozymes at Different Stages of Danio rerioOntogenesis

We studied properties of lactate dehydrogenase isozymes expressed at different stages of Danio rerioontogenesis. H₄-LDH and a minor fraction H₃M₁are expressed during embryonic development. The muscle isozyme (₄) appears after the beginning of muscle contractions in the embryo. ₄and ₄isozymes isolated from the heart and skeletal muscle of the adult fish, respectively, show significant differences in terms of Michaelis constant (K _m) activation energy (AE), and inactivation temperature. H₄-LDH isozymes isolated from unfertilized eggs, the skeletal muscle of larvae, and the heart of the adult fish differ inK _mand activation energy, as well as in inactivation temperature. We propose that these differences may be associated with a ligand interacting with the H₄isozyme at different steps of ontogenesis.     

Abundance,size, and feeding success of larval shortnose suckers and Lost River suckers from different habitats of the littoral zone of Upper Klamath Lake

We examined near-shore habitat use by larval shortnose and Lost River suckers in the lower Williamson River and Upper Klamath Lake of south-central Oregon. Emergent macrophytes Scirpus, Sparganium and Polygonum supported significantly more, larger, and better-fed larvae than submergent macrophytes, woody vegetation, or open water. Abundance, size, and gut fullness were similar for sucker larvae collected from different emergent macropytes. During the larval period, there was no evidence of density dependant effects or habitat shifts. Ranked catch per unit effort data indicated potential predators also were more likely to use emergent macrophytes, but ordination indicated larvae and potential predators were differentially distributed along a vegetation structure-water depth gradient with larvae in shallow vegetated areas. Between-habitat differences appeared to be due to larval sucker selection for, or better survival in, emergent macrophytes, rather than differential access or exclusion from other habitats. The importance of emergent macrophytes appears to be related to increased foraging success and reduced predation. Because larvae in emergent macrophytes have a size and gut fullness advantage, the amount of emergent habitat could affect early survival. However, interannual differences in recruitment to the adult population may or may not be dependent on larval dynamics. Our results suggest larval sucker access to emergent macrophytes may be necessary, but perhaps not sufficient, for promoting good year class formation.     

不同光质补光对促早栽培‘瑞都香玉’葡萄果实品质的影响

以4年生‘贝达’嫁接的早熟葡萄品种‘瑞都香玉’为试材,研究设施促早栽培条件下,紫外光、蓝光和红蓝光不同光质补光对果实品质的影响,结果表明: 促早栽培节能日光温室内环境属于典型的弱蓝紫光和弱紫外光环境.与对照(未补光)相比,夜间6 h的蓝光和紫外光补光处理可显著加快葡萄果实发育过程中质量和果粒纵横径的增大、果实糖含量的升高以及酸含量的下降,红蓝光效果不明显.果实成熟期紫外光补光处理果实的单粒质量最高,蓝光与红蓝光处理显著高于对照;蓝光补光处理果实葡萄糖、果糖和总糖含量最高,紫外光次之,红蓝光略高于对照.与对照相比,蓝光补光处理可显著加快果实中里那醇、α-萜品醇、橙花醇等萜烯类组分含量高峰的出现,而紫外光、红蓝光补光处理差异较小.果实成熟期蓝光补光处理果实中里那醇、香茅醇等萜烯类物质含量最高,紫外光补光处理里那醇含量较高,香叶醇、己醛、E-2-己烯醛等主要香气物质的含量最高,而红蓝光补光处理里那醇的含量与对照相比有所降低.紫外光、蓝光和红蓝光3种光质补光处理均增加了果实中醛酮类物质的种类及含量.表明蓝光补光处理果实发育最快,成熟最早,糖含量最高,里那醇等萜烯类物质含量高峰出现的时间最早;紫外光补光处理果实的单粒质量最大,主要萜烯类组分含量高;红蓝光补光处理对改善果实品质的效果不明显.     

No skeletal dysplasia in the nariokotome boy KNM‐WT 15000 (homo erectus)—A reassessment of congenital pathologies of the vertebral column

The Nariokotome boy skeleton KNM‐WT 15000 is the most complete Homo erectus fossil and therefore is key for understanding human evolution. Nevertheless, since Latimer and Ohman (2001) reported on severe congenital pathology in KNM‐WT 15000, it is questionable whether this skeleton can still be used as reference for Homo erectus skeletal biology. The asserted pathologies include platyspondylic and diminutive vertebrae implying a disproportionately short stature; spina bifida; condylus tertius; spinal stenosis; and scoliosis. Based on this symptom complex, the differential diagnosis of spondyloepiphyseal dysplasia tarda, an extremely rare form of skeletal dysplasia, has been proposed. Yet, our reanalysis of these pathologies shows that the shape of the KNM‐WT 15000 vertebrae matches that of normal modern human adolescents. The vertebrae are not abnormally flat, show no endplate irregularities, and thus are not platyspondylic. As this is the hallmark of spondyloepiphyseal dysplasia tarda and related forms of skeletal dysplasia, the absence of platyspondyly refutes axial dysplasia and disproportionate dwarfism. Furthermore, we neither found evidence for spina bifida occulta nor manifesta, whereas the condylus tertius, a developmental anomaly of the cranial base, is not related to skeletal dysplasias. Other fossils indicate that the relatively small size of the vertebrae and the narrow spinal canal are characteristics of early hominins rather than congenital pathologies. Except for the recently described signs of traumatic lumbar disc herniation, the Nariokotome boy fossil therefore seems to belong to a normal Homo erectus youth without pathologies of the axial skeleton. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.     

Chondrichthyan‐like scales from the Middle Ordovician of Australia

Abstract: Microvertebrate sampling of the Stairway Sandstone (Darriwilian, Middle Ordovician, central Australia) has yielded scales that are chondrichthyan‐like in their overall construction, and Tantalepis gatehousei gen. et sp. nov. is erected here to describe these specimens. Tantalepis gatehousei gen. et sp. nov. is the stratigraphically oldest microsquamous taxon described thus far, and the ‘shark‐like’ appearance of the scales may extend the chondrichthyan lineage back into the Middle Ordovician. The presence of ‘shark‐like’ scales in the fossil record some 50 myr prior to the first articulated chondrichthyan body fossils and 44 myr before the first clearly identifiable chondrichthyan teeth suggests there is a considerable scope for the recovery of articulated specimens with which to document the early history of crown gnathostomes. Traditional hypotheses of phylogenetic relationships among early jawed vertebrates were recently challenged by the proposal of a radically different tree topology. However, the development of a new data set specifically addressing scale‐based characters is required before taxa such as Tantalepis, that are based upon disarticulated remains alone, can be firmly placed within the emerging, revised, evolutionary narrative.