Electromagnetic interference caused by common surgical energy-based devices on an implanted cardiac defibrillator

Background

Surgical energy-based devices emit energy, which can interfere with other electronic devices (eg, implanted cardiac pacemakers and/or defibrillators). The purpose of this study was to quantify the amount of unintentional energy (electromagnetic interference [EMI]) transferred to an implanted cardiac defibrillator by common surgical energy-based devices.

Methods

A transvenous cardiac defibrillator was implanted in an anesthetized pig. The primary outcome measure was the average maximum EMI occurring on the implanted cardiac device during activations of multiple different surgical energy-based devices.

Results

The EMI transferred to the implanted cardiac device is as follows: traditional bipolar 30 W .01 ± .004 mV, advanced bipolar .004 ± .003 mV, ultrasonic shears .01 ± .004 mV, monopolar Bovie 30 W coagulation .50 ± .20 mV, monopolar Bovie 30 W blend .92 ± .63 mV, monopolar instrument without dispersive electrode .21 ± .07 mV, plasma energy 3.48 ± .78 mV, and argon beam coagulator 2.58 ± .34 mV.

Conclusion

Surgeons can minimize EMI on implanted cardiac defibrillators by preferentially utilizing bipolar and ultrasonic devices.     

New clues to identify proteins correlated with Attractin

In our previous study, the age‐dependent testis vacuolisation and sperm dysfunction were found in Attractin (Atrn)‐deficient mice, Atrn^mg‐3J, which is a null or nearly null allele. To explore the potential mechanism involved in these pathological changes, Attractin knock‐down in mouse Sertoli cells TM4 (psiAtrn‐TM4) was successfully established by stable RNA interference. The TM4 transfected by psiRNA‐hH1 (psiRNA‐TM4) was the control group, in which the expression of Atrn was not affected. The proteomic changes among the psiAtrn‐TM4, primary cultures of Sertoli cells of Atrn^mg‐3J (mu‐Sc) and control cells (psiRNA‐TM4) were compared by two‐dimensional gel electrophoresis. Fifteen differentially expressed protein spots of those cells were identified by matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry and the NCBI proteins database. Except the decreased expression of superoxide dismutase (SOD), there were several novel proteins associated with Atrn function, including downregulated ATP synthase, peroxiredoxin 2 and upregulated caspase 6, ketohexokinase, etc., in psiAtrn‐TM4 and mu‐Sc. These data suggest that these differentially expressed proteins may be associated with the function of Atrn in Sertoli cells, thus providing a new clue to interpret the mechanism of testis degeneration in Atrn mutants.     

RNA干扰TEAD基因对舌癌细胞系Tca8113增殖和侵袭的影响

目的：应用RNA干扰技术抑制人舌癌细胞株Tca8113中内源TEAD基因的水平,观察TEAD基因对舌癌细胞生物学行为的影响。方法：构建针对TEAD基因特异性siRNA真核表达载体,将其转染至Tea8113,采用RT—PCR法检测转染后的Tca8113细胞中TEAD基因的表达。采用CCK8技术检测细胞的增殖情况,采用Transwell法检测细胞的迁移情况。实验数据采用SPSSl3．0软件包进行单因素方差分析。结果：siRNA干扰Tea8113细胞后,TEAD基因的表达水平显著下降（P〈0．05）,细胞生长缓慢,体外侵袭能力下降。结论：通过RNA干扰技术阻断TEAD的表达,可抑制,rca8113细胞的生长、增殖、迁移,提示TEAD基因在舌癌的发生、发展过程中起着重要作用。     

Combined fluorescent and electron microscopic imaging unveils the specific properties of two classes of meiotic crossovers

Crossovers (COs) shuffle genetic information and allow balanced segregation of homologous chromosomes during the first division of meiosis. In several organisms, mutants demonstrate that two molecularly distinct pathways produce COs. One pathway produces class I COs that exhibit interference (lowered probability of nearby COs), and the other pathway produces class II COs with little or no interference. However, the relative contributions, genomic distributions, and interactions of these two pathways are essentially unknown in nonmutant organisms because marker segregation only indicates that a CO has occurred, not its class type. Here, we combine the efficiency of light microscopy for revealing cellular functions using fluorescent probes with the high resolution of electron microscopy to localize and characterize COs in the same sample of meiotic pachytene chromosomes from wild-type tomato. To our knowledge, for the first time, every CO along each chromosome can be identified by class to unveil specific characteristics of each pathway. We find that class I and II COs have different recombination profiles along chromosomes. In particular, class II COs, which represent about 18% of all COs, exhibit no interference and are disproportionately represented in pericentric heterochromatin, a feature potentially exploitable in plant breeding. Finally, our results demonstrate that the two pathways are not independent because there is interference between class I and II COs.Eukaryotic sexual reproduction involves meiosis, a specialized cell division in which DNA duplication in a diploid cell is followed by two cell divisions to produce four haploid cells. The first division, Meiosis I, involves crossing over and chiasmata formation between each pair of homologous chromosomes, thereby ensuring separation of the homologs and formation of two haploid cells, each with one complete set of replicated chromosomes. The second division, Meiosis II, is a mitosis-like division in which the two sister chromatids separate to yield four haploid cells that directly or indirectly form gametes. Because these four products are genetically unique due to crossing over and independent segregation of homologous chromosomes during Meiosis I, meiosis plays an important role in creating genetic diversity in sexually reproducing organisms.Crossing over during meiosis is tightly controlled so each pair of homologs has at least one “obligate” crossover (CO) that ensures balanced reductional segregation, but the presence of a CO reduces the likelihood of another CO in its vicinity, a phenomenon referred to as CO interference (1, 2). Significant progress has been made recently in illuminating the molecular events of meiotic recombination and the control of crossing over (3–8). The initiating event of meiotic recombination in most organisms is formation of numerous DNA double-strand breaks (DSBs). Homolog-dependent repair of a DSB may follow any one of at least three pathways: (i) non-CO that may result in a short gene conversion; (ii) CO with interference (class I COs, produced by pathway P1); or (iii) CO without interference (class II COs, produced by pathway P2) (6, 7, 9). The interfering CO pathway involves the resolution of double Holliday junctions, which requires many proteins including the ZMM group (ZIP1-4, MSH4-5, MER3) and the MutL homolog 1 (MLH1)/MLH3 complex (6, 10). The noninterfering CO pathway depends primarily on the Mus81/Mms4 endonuclease complex in budding yeast (MUS81/EME1 complex in plants and animals) (5–7, 11–14).Meiotic COs occur in association with two cytological structures, synaptonemal complexes (SCs) that link each pair of homologous chromosomes throughout their lengths during pachytene and late recombination nodules (RNs) that are ellipsoidal structures on SCs (15). Every SC has at least one RN, each RN marks a CO site, and most RNs contain MLH1 protein (16–19). RNs are too small (50-100 nm) to be resolved using light microscopy (LM), but they can be readily visualized by transmission electron microscopy (EM), particularly in 2D spreads of SCs (18). Antibodies to MLH1 protein have been used as immunofluorescent probes to map class I COs on SCs (e.g., refs. 19 and 20). Pathway 2 (P2), which was revealed using mutants of the P1 pathway, produces class II COs, and these class II COs showed no interference in the marker intervals studied (21–23). The P1 pathway produces the majority of COs, and the P2 pathway accounts for ∼5–30% of COs (8, 11, 21). CO distributions have been effectively modeled by assuming that class II COs are independent from class I COs (24). However, class II COs have not been independently mapped on chromosomes (12), and little is known about the properties of each pathway or whether they interact in wild-type organisms.Here, we describe an advanced approach that uses SC spreads from wild-type tomato (Solanum lycopersicum, 2n = 2x = 24) to directly identify the pathway of origin for each CO in individual meiotic nuclei. For this, we superimposed the immunofluorescent LM image of an SC spread showing MLH1 foci (class I COs) onto an EM image of the same SC spread showing RN locations (all COs). RNs that coincide with MLH1 foci (MLH1-positive RNs) mark class I COs, and RNs that do not coincide with MLH1 foci (MLH1-negative RNs) are considered to mark class II COs. Because EM is time-consuming, this approach takes advantage of both the relative speed of LM and the high resolution of EM, allowing us to analyze RNs on 1882 tomato SCs.     

Artificial selection for structural color on butterfly wings and comparison with natural evolution

Brilliant animal colors often are produced from light interacting with intricate nano-morphologies present in biological materials such as butterfly wing scales. Surveys across widely divergent butterfly species have identified multiple mechanisms of structural color production; however, little is known about how these colors evolved. Here, we examine how closely related species and populations of Bicyclus butterflies have evolved violet structural color from brown-pigmented ancestors with UV structural color. We used artificial selection on a laboratory model butterfly, B. anynana, to evolve violet scales from UV brown scales and compared the mechanism of violet color production with that of two other Bicyclus species, Bicyclus sambulos and Bicyclus medontias, which have evolved violet/blue scales independently via natural selection. The UV reflectance peak of B. anynana brown scales shifted to violet over six generations of artificial selection (i.e., in less than 1 y) as the result of an increase in the thickness of the lower lamina in ground scales. Similar scale structures and the same mechanism for producing violet/blue structural colors were found in the other Bicyclus species. This work shows that populations harbor large amounts of standing genetic variation that can lead to rapid evolution of scales’ structural color via slight modifications to the scales’ physical dimensions.Organisms produce colors in two basic ways: by synthesizing pigments that selectively absorb light of certain spectral bands so that only light outside the absorption bands is backscattered (chemical color) or by developing nanomorphologies that enhance the reflection of light of certain wavelengths by interference (physical color or structural color). Structural colors play major roles in natural and sexual selection in many species (1) and have a broad range of applications in color display, paint, cosmetics, and textile industries (2). Structural color surveys across widely divergent species have revealed a large diversity of color-producing mechanisms (3–9). However, there has been a lack of systematic study and comparison of how different colors from closely related species or within populations of a single species evolve, even though these colors can vary dramatically. By examining how these species/populations evolve different colors, it is possible to identify the minimal amount of morphological change that results in significant color variation. Furthermore, this research may serve as an inspiration for future application of similar evolutionary principles to the design of photonic devices for color tuning, light trapping, or beam steering (2, 10–20). From an evolutionary biology point of view, we are curious to examine how structural colors respond to selection pressure and whether there is sufficient standing genetic variation in natural populations to allow the rapid evolution of novel colors. Here we focus on determining the morphological changes and the physical mechanisms that cause the evolution of violet structural color in populations of a single species and also across different species within a single genus of butterflies.We focus on the genus Bicyclus (Lepidoptera: Nymphalidae), composed of more than 80 species that predominantly exhibit brown color along with marginal eyespots. Some Bicyclus species, however, have independently evolved transverse bands of bright violet/blue structural color on the dorsal surface of the forewings (black asterisks in Fig. 1A) (21, 22). One species, Bicyclus anynana, has become a model species amenable to laboratory rearing, and multiple aspects of its marginal eyespots (size, relative width of the color rings, shape) have been altered by artificial selection (23–27). However, change of color (hue), either pigmentary or structural, via artificial selection has not been reported. B. anynana does not exhibit bright violet coloration on its wings and therefore provides an excellent opportunity for investigating whether there is genetic potential to produce violet color upon directed selection. We investigated this potential by performing an artificial selection experiment in B. anynana that targeted the color of the specific dorsal wing region that evolved violet/blue coloration in other members of the genus (Fig. 1 B–G).Open in a separate windowFig. 1.Structural color in Bicyclus butterflies and basic wing scale morphology. (A) A phylogenetic estimate of Bicyclus butterfly relationships (modified from ref. 41) illustrating the evolution of color in the genus. The black asterisks mark two clades that evolved violet/blue color independently, represented here by B. sambulos and B. medontias. (B–D) Dorsal wing images of B. sambulos, B. anynana (the region used for artificial selection is marked by white asterisk), and B. medontias. (E–G) Graphs of reflectance spectra of the blue/violet wing band showing reflectance peaks in the 400–450 nm range and in the brown-colored homologous region in B. anynana with a UV reflectance peak centered at 300 nm (colored arrows). (H) 3D illustration of the wing and scales in the selected wing area of B. anynana. (I) Magnified view of the ripped region in H showing how cover (c; brown) and ground (g; green) scales are attached to the wing membrane (m, pink) and alternate along rows. Scales on the other (ventral) side of the wing membrane are visible also. (J) Cross-sectional view of a single scale showing the trabeculae (T) connecting the lower lamina (LL) to the upper lamina that includes ridges (R), microribs (Mr), and crossribs (Cr). Windows (W) are the spaces between the ridges and crossribs. Cover and ground scales have the same basic morphology. [llustrations in H–J courtesy of Katerina Evangelou (Central Saint Martin’s College, London).]B. anynana, like other butterflies, has two types of scales, cover and ground, which alternate within a row with cover scales partially covering the ground scales and the point where both scales attach to the wing membrane (Fig. 1 H and I and Fig. S1) (28). Both cover and ground scales contain a lower lamina with a continuous smooth surface below a region composed of longitudinal ridges and crossribs, collectively referred to as the “upper lamina” and connected to the lower lamina via pillars called “trabeculae” (Fig. 1J and Fig. S1) (6). Previous studies on butterflies showed that structural color can be produced by interference with light reflected from the overlapping lamella that build the longitudinal ridges, from microribs protruding from the sides of the longitudinal ridges, or from the lower lamina, which can vary in thickness and patterning (Fig. 1J) (29, 30). However, it is not clear how the violet/blue color is produced in members of the two Bicyclus clades that separately evolved this color, whether B. anynana can be made to evolve the same violet/blue color via artificial selection, and whether it will generate the color in the same way as the other species. To answer these questions, we conducted detailed optical characterization and structural analysis of butterfly wing scales from three separate species and artificially evolved populations of Bicyclus to illustrate how color is generated and how it has evolved.     

Inhibition of porcine endogenous retrovirus in PK15 cell line by efficient multitargeting RNA interference

To effectively suppress porcine endogenous retroviruses (PERV)s, RNAi technique was utilized. RNAi is the up‐to‐date skill for gene knockdown which simultaneously multitargets both gag and pol genes critical for replication of PERVs. Previously, two of the most effective siRNAs (gag2, pol2) were found to reduce the expression of PERVs. Concurrent treatment of these two siRNAs (gag2+pol2) showed knockdown efficiency of up to 88% compared to negative control. However, despite the high initial knockdown efficiency 48 h after transfection caused by siRNA, it may only be a transient effect of suppressing PERVs. The multitargeting vector was designed, containing both gag and pol genes and making use of POL II miR Expression Vector, which allowed for persistent and multiple targeting. This is the latest shRNA system technique expressing and targeting like miRNA. Through antibiotics resistance characteristics utilizing this vector, miRNA‐transfected PK15 cells (gag2‐pol2) were selected during 10 days. An 88.1% reduction in the level of mRNA expression was found. In addition, we performed RT‐activity analysis and fluorescence in situ hybridization assay, and it demonstrated the highest knockdown efficiency in multitargeting (gag2+pol2) miRNA group. Therefore, according to the results above, gene knockdown system (siRNA and shRNA) through multitargeting strategy could effectively inhibit PERVs.     

干扰磷脂爬行酶1基因表达对结直肠癌细胞增殖和粘附的影响

目的 探讨PLSCR1在结直肠癌细胞增殖和粘附过程中的作用.方法 常规培养3株结直肠癌细胞,采用免疫细胞染色和免疫印迹法筛选PLSCR1高表达的细胞株.设计三条RNA干扰片段及一条阴性对照片段,稳定转染高表达PLSCR1的结直肠癌细胞株,采用实时荧光定量PCR和免疫印迹法验证干扰结果,筛选出对PLSCR1蛋白抑制率最高的干扰片段,通过MTT方法来评估转染后结直肠癌细胞增殖能力的变化,采用细胞粘附实验来评估转染后结直肠癌细胞粘附能力的变化.结果 免疫细胞染色提示LoVo细胞株高表达PLSCR1,与免疫印迹法结果相一致;转染siRNA-390后,LoVo细胞株PLSCR1的mRNA抑制效果最为明显,抑制率为88.4％,免疫印迹法检测进一步验证siRNA-390片段抑制PLSCR1蛋白表达最为显著.MTT法、纤连蛋白,粘附和层连蛋白检测显示,siRNA-390干扰下调PLSCR1的表达后,细胞生长变缓,粘附能力下降.结论 干扰PLSCR1能显著抑制肿瘤的增殖和粘附能力,提示PLSCR1可能在结直肠癌浸润和转移中具有一定作用.     

个性化FITT运动方案对2型糖尿病患者HbA1c的影响

目的：明确个性化FITT运动方案对2型糖尿病患者HbA1c的影响。方法：将研究对象随机分为对照组与干预组,对照组予以常规运动指导,干预组制定个性化运动方案,分别收集两组患者入院时及出院三个月后的HbA1c值,比较其糖代谢水平和相关指标的变化。结果：干预组的HbA1c较三个月前有了显著降低,平均降低3.17%。实验组与对照组同期HbA1c变化相比有差异,实验组与对照组三个月后的HbA1c平均相差1.84%。结论：个性化的运动方案较之常规运动指导对控制患者的糖化血红蛋白、降低血糖有着更好的效果。     

SiRNA封闭MHC基因对鼠LAK细胞杀伤活性的影响

目的观察使用小干扰短链RNA(small interference RNA,siRNA)封闭BABL/C小鼠淋巴细胞MHC-Ⅰ基因(H-2K~d)对H-2K~d表达的影响及H-2K~d表达降低的淋巴因子激活的杀伤细胞(lym- phokine activated killer cell,LAK)杀伤活性的改变,探讨淋巴细胞MHC-Ⅰ在肿瘤免疫中的作用。方法在4×10~5/ml的LAK细胞的24孔培养板中分别加入H-2K~d-siRNA,单纯转染剂和无义siRNA。免疫荧光流式细胞术定量检测siRNA对LAK细胞H-2K~d表达抑制作用,LDH释放试验检测H-2K~d表达降低的LAK细胞肿瘤杀伤活性。结果流式细胞术测定结果:siRNA组H-2K~d蛋白的表达率下降(P<0.01)。LDH释放试验显示(E/T=40/1):对H22和K562肿瘤细胞的杀伤活性降低(P<0.01)。结论不同比例H-2K~d-siRNA和助转染剂均能有效抑制小鼠LAK细胞表面H-2K~d的表达,其中以1.6μg/8μL效果最佳。不同浓度的siRNA均不影响淋巴细胞增殖活性,对淋巴细胞无毒副作用。H-2K~d-siRNA通过抑制鼠LAK细胞的H-2K~d的表达,导致鼠LAK细胞对H22及K562肿瘤细胞的杀伤活性降低。说明H-2K~d是鼠LAK细胞杀伤作用的重要因子,本实验为构建H-2K~d降低的体内实验模型提供了基础。