Comparing parametric solid modelling/reconfiguration,global shape modelling and free-form deformation for the generation of 3D digital models of femurs from X-ray images

At present, computer assisted surgery systems help orthopaedic surgeons both plan and perform surgical procedures. To enable these systems to function, it is crucial to have at one's disposal 3D models of anatomical structures, surgical tools and prostheses (if required). This paper analyses and compares three methods for generating 3D digital models of anatomical structures starting from X-ray images: parametric solid modelling/reconfiguration, global shape modelling and free-form deformation. Seven experiences involving the generation of a femur model were conducted by software developers and different skilled users. These experiences are described in detail and compared at different stages and from different points of view.     

Are multiple predator effects directed by prey availability?

Antagonistic/synergistic interactions among predators foraging on the same prey have been assumed to play a major role in shaping community structure. Studies in systems with multiple predator species have shown that the strength of these interactions may not be predictable and is largely dependent on individual behavioural traits, species density and habitat complexity. Although the association of prey consumption and satiation of a foraging predator has long been recognized, there has been relatively little research on how prey availability affects multiple predators’ effects. In this work, we present a framework to investigate the variation in two coexisting/competing predators’ effects on prey risk as affected by the prey availability rate. Functional responses by each predator species were first studied in single-predator treatments. Then, the intra- and inter-specific competition was investigated by employing additive and substitutative experimental designs to highlight the nature of multiple effects. Intra- and interspecific interactions were found to be similar and there was risk reduction, and risk enhancement for the prey at intermediate and high levels, respectively, according to the multiplicative risk model (MRM). The results indicated that when similar predators are concerned, the outcomes of MRM may vary according to the functional response curve of these predators. Thus, studies involving a wide range of prey densities are required to explore the nature of interactions. Moreover, this kind of experimental data can contribute to unravelling complexities in theoretical approaches by earlier studies and ultimately promote understanding the effect of multiple predators on prey population regulation.     

Illuminating the complexity of GPCR pathway selectivity – advances in biosensor development

It should come as no surprise that G protein-coupled receptors (GPCRs) continue to occupy the focus of drug discovery efforts. Their widespread expression and broad role in signal transduction underline their importance in human physiology. Despite more than 800 GPCRs sharing a common architecture, unique differences govern ligand specificity and pathway selectivity. From the relatively simplified view offered by classical radioligand binding assays and contractility responses in organ baths, the road from ligand binding to biological action has become more and more complex as we learn about the molecular mediators that underly GPCR activation and translate it to physiological outcomes. In particular, the development of biosensors has evolved over the years to dissect the capacity of a given receptor to activate individual pathways. Here, we discuss how recent biosensor development has reinforced the idea that biased signaling may become mainstream in drug discovery programs.     

Morphological integration and modularity in the hyperkinetic feeding system of aquatic‐foraging snakes

The kinetic skull is a key innovation that allowed snakes to capture, manipulate, and swallow prey exclusively using their heads using the coordinated movement of eight bones. Despite these unique feeding behaviors, patterns of evolutionary integration and modularity within the feeding bones of snakes in a phylogenetic framework have yet to be addressed. Here, we use a dataset of 60 μCT‐scanned skulls and high‐density geometric morphometric methods to address the origin and patterns of variation and integration in the feeding bones of aquatic‐foraging snakes. By comparing alternate superimposition protocols allowing us to analyze the entire kinetic feeding system simultaneously, we find that the feeding bones are highly integrated, driven predominantly by functional selective pressures. The most supported pattern of modularity contains four modules, each associated with distinct functional roles: the mandible, the palatopterygoid arch, the maxilla, and the suspensorium. Further, the morphological disparity of each bone is not linked to its magnitude of integration, indicating that integration within the feeding system does not strongly constrain morphological evolution, and that adequate biomechanical solutions to a wide range of feeding ecologies and behaviors are readily evolvable within the constraint due to integration in the snake feeding system.     

Loss of forest cover and host functional diversity increases prevalence of avian malaria parasites in the Atlantic Forest

Host phylogenetic relatedness and ecological similarity are thought to contribute to parasite community assembly and infection rates. However, recent landscape level anthropogenic changes may disrupt host-parasite systems by impacting functional and phylogenetic diversity of host communities. We examined whether changes in host functional and phylogenetic diversity, forest cover, and minimum temperature influence the prevalence, diversity, and distributions of avian haemosporidian parasites (genera Haemoproteus and Plasmodium) across 18 avian communities in the Atlantic Forest. To explore spatial patterns in avian haemosporidian prevalence and taxonomic and phylogenetic diversity, we surveyed 2241 individuals belonging to 233 avian species across a deforestation gradient. Mean prevalence and parasite diversity varied considerably across avian communities and parasites responded differently to host attributes and anthropogenic changes. Avian malaria prevalence (termed herein as an infection caused by Plasmodium parasites) was higher in deforested sites, and both Plasmodium prevalence and taxonomic diversity were negatively related to host functional diversity. Increased diversity of avian hosts increased local taxonomic diversity of Plasmodium lineages but decreased phylogenetic diversity of this parasite genus. Temperature and host phylogenetic diversity did not influence prevalence and diversity of haemosporidian parasites. Variation in the diversity of avian host traits that promote parasite encounter and vector exposure (host functional diversity) partially explained the variation in avian malaria prevalence and diversity. Recent anthropogenic landscape transformation (reduced proportion of native forest cover) had a major influence on avian malaria occurrence across the Atlantic Forest. This suggests that, for Plasmodium, host phylogenetic diversity was not a biotic filter to parasite transmission as prevalence was largely explained by host ecological attributes and recent anthropogenic factors. Our results demonstrate that, similar to human malaria and other vector-transmitted pathogens, prevalence of avian malaria parasites will likely increase with deforestation.     

Implications of comparative ventral body wall histology on selection of abdominal surgical approach and closure in 12 species of fish

A ventral midline surgical approach for fish celiotomy is commonly performed in veterinary clinical medicine and research, although the relevant ventral body wall anatomy of many fish species is not well documented. Histological evaluation of tissue samples from the ventral body wall of 12 fish species was performed to provide a reference for surgical approach and closure decisions. The width between muscle bundles running parallel to the long axis and total thickness of tissue layers varied among species. An appreciable space between longitudinal muscles of the ventral body wall and a lack of muscle, vessels and nerves on midline in all species examined supports recommendations of ventral midline incisions to spare important structures. Dense connective tissue consistent with an aponeurosis between musculature along the ventral body wall was not observed in any species evaluated. Connective tissue was concentrated within the dermis of all species evaluated, with an additional layer of collagen along the coelomic membrane in Russian sturgeon Acipenser gueldenstaedtii, koi Cyprinus carpio, goldfish Carassius auratus, black drum Pogonias cromis, black seabass Centropristis striata, tomtate Haemulon aurolineatum and scup Stenotomus caprinus. A sufficiently wide space on ventral midline for practical targeting during the surgical approach is present in A. gueldenstaedtii, C. carpio, striped bass Morone saxatilis, H. aurolineatum, P. cromis, rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta. Sand perch Diplectrum formosum, C. auratus, S. caprinus, grey triggerfish Balistes capriscus and black sea bass Centropristis striata have a negligible space between longitudinal muscles on midline. The variation in ventral body wall structure observed in this study helps inform surgical decision making for celiotomy incision and closure in these species.     

Protective role of TIRAP functional variant against development of coronary artery disease

Coronary artery disease (CAD) is the leading cause of sudden death worldwide. Inflammation is proved to be an important player in development of the CAD. Inflammation is directly regulated by the Toll like receptors (TLRs). Susceptibility of CAD is influenced by genetic variations within TLRs and the proteins involved in its signaling cascade. The TIRAP/MAL {TIR domain containing adaptor protein / MyD88 (myeloid differentiation primary response gene 88) adaptor-like} exhibits maximum genetic variations of all adaptor proteins involved in TLR signaling cascade. Susceptibility to a number of diseases can be influenced due to presence of S180L single nucleotide polymorphism (SNP) of TIRAP/MAL. This study was conducted to investigate the functional role of this well characterized S180L polymorphism on susceptibility to CAD among Pakistani patients. A total of 146 Pakistani CAD patients and 147 controls were genotyped by Amplification Refractory Mutation System-Polymerase Chain Reaction (ARMS-PCR) and the data was analyzed by using 2-tailed Chi square (x²) test. The p value ≤ 0.05 was considered to be significant.Significantly high frequency of homozygous L180L genotype was observed among healthy subjects as compared to the CAD patients [24 (16%) vs 7 (5%); x² 11.85; p = 0.003]. Moreover, the allele frequency of the minor allele; 180L was observed to be significantly higher among controls than the CAD patients, having same direction of association [156 (53%) vs 131 (45%); OR (95% CI) = 0.7198 (0.520–0.996); p < 0.05).Our results indicate that protective effect of L180L; a coding variant of TIRAP/MAL against CAD is discernible.     

罗伊氏乳杆菌(息敏乐)辅助治疗儿童功能性便秘的多中心研究

目的探讨罗伊氏乳杆菌(息敏乐)辅助治疗儿童功能性便秘的临床疗效及安全性,为后续研究提供参考。方法选择2016年6月至2018年6月期间5个研究中心收治的237例功能性便秘患儿为研究对象,按照随机数表法分为对照组(n=76)、观察A组(n=78)、观察B组(n=83)。对照组患儿采用饮食调节及排便习惯锻炼等常规治疗,观察组患儿在此基础上加用息敏乐治疗,其中观察A组剂量为1次/d,观察B组剂量为2次/d,3组患儿均持续治疗4周并随访2个月。对比3组患儿治疗后总有效率、大便性状评分、排便困难评分、每周排便次数、排便时间、排便间隔、粪便pH值、肠道菌群变化、复发率及不良反应情况。结果治疗后观察B组患儿的总有效率(93.98%)明显高于对照组(80.26%)及A组(85.90%),每周排便次数及肠道乳杆菌数量多于对照组及A组,排便时间短于对照组,排便间隔短于对照组及A组,粪便性状评分、排便困难评分、粪便pH值、肠道产气夹膜梭菌、肠球菌、肠杆菌数量及复发率明显低于对照组及A组(均P0.05)。3组患儿不良反应发生率差异无统计学意义(P0.05)。结论罗伊氏乳杆菌辅助治疗可调节功能性便秘患儿肠道菌群平衡,疗效显著,患儿不易复发,安全性较高。     

经皮椎间孔镜下髓核摘除术治疗腰椎间盘突出症的临床疗效及术后复发的影响因素分析

目的:探讨经皮椎间孔镜下髓核摘除术治疗腰椎间盘突出症(LDH)的临床疗效,分析术后复发的影响因素。方法:选取我院于2017年2月~2019年12月期间收治的LDH患者230例,均给予经皮椎间孔镜下髓核摘除术治疗,观察其疗效、不同时间点视觉疼痛模拟评分量表(VAS)、Oswestry功能障碍指数(ODI)评分及并发症。记录LDH术后复发(PRLDH)率。采用单因素及多因素Logistic回归分析PRLDH的影响因素。结果:230例LDH患者采用经皮椎间孔镜下髓核摘除术治疗后,优69例,良117例,可34例,差10例,优良率为80.87%(186/230)。LDH患者术后3个月、术后6个月VAS、ODI评分均较术前降低,且术后3个月~术后6个月VAS、ODI评分呈降低趋势,差异均有统计学意义(P<0.05)。LDH患者术后并发症发生率为5.22%(12/230)。发生PRLDH的患者为29例,复发率为12.61%(29/230)。单因素分析显示,PRLDH与年龄、吸烟、体质量指数、糖尿病、髓核突出/脱出、病程有关(P<0.05);多因素Logistic回归分析显示,年龄≥60岁、吸烟、体质量指数≥24kg/m²、糖尿病、髓核突出/脱出、病程≥6个月均是PRLDH复发的影响因素(P<0.05)。结论:经皮椎间孔镜下髓核摘除术用于LDH的治疗,疗效稳定,可较好的促进患者疼痛症状的改善,加快腰椎功能的恢复,但术后复发问题需得到重视,年龄≥60岁、吸烟、体质量指数≥24kg/m²、糖尿病、髓核突出/脱出、病程≥6个月均是PRLDH的影响因素。     

基于加速康复外科理念的前交叉韧带重建术中麻醉方式的选择

摘要 目的：基于加速康复外科理念,比较分析收肌管阻滞和股神经阻滞两组麻醉方式术后早期反应,探讨其在ACL重建术中的应用。方法：选取符合手术条件的88名ACL损伤的患者,随机分为收肌管阻滞组和股神经阻滞组,手术均在全麻下由同一组医生实施,采用自体腘绳肌重建ACL。比较术后早期2h,4 h,8 h,24 h和48 h患者静息和主动活动时VAS评分;患者首次主动直腿抬高时间;首次自主下地时间;48 h内追加盐酸哌替啶的的人次数;以及不良反应的例数。分析比较两组麻醉方式在术后早期的不同。结果：收肌管阻滞组患者在术后首次直腿抬高的时间和首次自主下地时间两方面与股神经阻滞组相比较,差异有统计学意义（P＜0.05）;两组患者在术后2 h,4 h,8 h,24 h和48 h静息和主动活动时疼痛程度以及48 h内追加盐酸哌替啶的人次数和不良反应的例数之间差异无统计学意义（P＞0.05）。结论：收肌管阻滞能够满足ACL重建术后的早期康复需要,在术后早期对股四头肌的影响较小,有助于患者早期康复,是一种安全、有效的麻醉方式。