Shock wave therapy for femoral head necrosis—Pressure measurements inside the femoral head

There is a persisting need for effective therapies of femoral head necrosis, a common bone disease. Promising clinical results have been stated for the treatment with extracorporeal shock waves (ESW). However, the effective remaining pressure in the target region inside the femoral head has never been determined. Aim of this study was to investigate whether ESW are able to propagate through bone without an excessive loss of pressure. The remaining ESW pressure generated by an electromagnetic device after passing a certain intraosseous distance within the femoral head was measured. Standardized holes were drilled in porcine femora and the absorption in relation to reference measurements in degassed water was determined. The results showed continuous attenuation of shock waves in bone. After a clinical relevant intraosseous distance of 10 mm an ESW pressure of ～50% remained.In conclusion, ESW have the potential to reach necrotic regions with therapeutic pressure levels and to effectively treat femoral head necrosis.     

Does trabecular bone structure within the metacarpal heads of primates vary with hand posture?

Reconstructing function from hominin fossils is complicated by disagreements over how to interpret primitively inherited, ape-like morphology. This has led to considerable research on aspects of skeletal morphology that may be sensitive to activity levels during life. We quantify trabecular bone morphology in three volumes of interest (dorsal, central, and palmar) in the third metacarpal heads of extant primates that differ in hand function: Pan troglodytes, Pongo pygmaeus, Papio anubis, and Homo sapiens. Results show that bone volume within third metacarpal heads generally matches expectations based on differences in function, providing quantitative support to previous studies. Pongo shows significantly low bone volume in the dorsal region of the metacarpal head. Humans show a similar pattern, as manipulative tasks mostly involve flexed and neutral metacarpo-phalangeal joint postures. In contrast, Pan and Papio have relatively high bone volume in dorsal and palmar regions, which are loaded during knuckle-walking/digitigrady and climbing, respectively. Regional variation in degree of anisotropy did not match predictions. Although trabecular morphology may improve behavioral inferences from fossils, more sophisticated quantitative strategies are needed to explore trabecular spatial distributions and their relationships to hand function.     

Metal trabecular bone reconstruction system better improves clinical efficacy and biomechanical repair of osteonecrosis of the femoral head than free vascularized fibular graft: A case–control study

In this study, we aim to compare and analyze the biomechanical repair and clinical efficacy of osteonecrosis of the femoral head (ONFH) with the use of metal trabecular bone reconstruction system and free vascularized fibular graft. The study enrolled 66 adult patients from medical records of nontraumatic ARCO 2A–3B stage ONFH. A simple ONFH model without surgical treatment was established in 13 cases, 29 cases were treated with metal trabecular bone reconstruction system, and 24 cases were treated with free vascularized fibular graft. Computer-recognized and extracted femur outlines were imported, and three-dimensional reconstructions were performed. The stress concentration and stress peak value were analyzed, and the Harris score, visual analog scale pain score, and operation status of the above patients were compared. Finally, quality of life assessment was performed using SF-36 scale. Metal trabecular bone reconstruction system provided less operation time, blood loss, and the total length of postoperative hospital stay than free vascularized fibular graft. Metal trabecular bone reconstruction system promoted bone reconstruction, increased bone mineral density and Harris score. The total clinical effective rate of young patients (20–40 years) was higher than that of older patients (41–60 years). Metal trabecular bone reconstruction system provided higher physical component summary, mental component summary, and role/social component summary than free vascularized fibular graft. This study demonstrates that both metal trabecular bone reconstruction system and free vascularized fibular graft can prevent or delay the progression of ONFH, while metal trabecular bone reconstruction system is a better choice because of better short-term clinical efficacy.     

Metabolomic study of the bone trabecula of osteonecrosis femoral head patients based on UPLC–MS/MS

The severity and/or progression of osteonecrosis of the femoral head (ONFH) are commonly assessed by radiography, nuclear magnetic resonance image which aren’t invariably correlated to severity of disease and may be disturbed by other factors. Consequently, exploring the novel biochemical signatures of ONFH may be beneficial for diagnosing and understanding this disease. In this work, a bone trabecula metabolomics was undertaken to determine the expression pattern of low molecular mass metabolites in patients of femoral head necrosis based on the ultra-performance liquid chromatography/time-of-flight tandem mass spectrometry (UPLC/TOF MS/MS). Histological study showed that necrotic bone was characterized by necrosis, fibrosis and lacuna, but adjacent “normal” bone was pathologically normal. Principal component analysis in combination with orthogonal partial least-squares discrimination analysis was used to find out changed metabolites. MS/MS was used to speculate the corresponding molecule. Both osteonecrotic bone trabecula (ONBT) and adjacent “normal” bone trabecula (ANBT) showed higher levels of amino acids, such as proline, arginine, glutamine, dipeptides and lower levels of antioxidants. Most disrupted lipids, such as fatty acid esters, glycerophospholipids, sphingolipids, were found in osteonecrotic zone. The area under the receiver operating characteristic curve of combinational biomarkers (d-arginine, l-proline, l-carnitine, inosine) in ONBT and ANBT was 0.996 and 0.950, respectively. Our findings might provide a significant insight to understand the metabolic mechanism and diagnosis biomarkers of ONFH in the future.     

Do different locomotor modes during growth modulate trabecular architecture in the murine hind limb?

Vertebrate morphologists often implicate functional adaptationsof bone to mechanical milieus when comparing animals with distinctbehavioral repertoires. Functional morphologists frequentlyuse comparative osteology and locomotor behavior to constructcorrelative form–function relationships. While some experimentalwork has investigated functional adaptations of bone elicitedby specific locomotor behaviors, these studies usually manipulaterepertoires by introducing artificial situations (e.g., treadmills)or creating differences in the level of activity (i.e., exercise),either of which can compromise extrapolations to free-ranginganimals. Here, we present trabecular bone morphology and microarchitecturefrom an inbred mouse model in which components of naturalisticlocomotor repertoires were accentuated. Using inbred mice, wecontrol for genetic variability, further isolating the osteogenicresponses to these behaviors. Single female (BALB/cByJ) mice(n = 10 per group) were housed for 8 weeks beginning at 30 dayspostbirth in custom-designed cages that accentuated either linearquadrupedalism or turning. Concurrently, mice in a control groupwere housed singly in open cages. The distal femoral metaphysiswas scanned by micro-computed tomography at the end of the 8-weekexperiment protocol. The experimental groups, particularly the"linear" group, differed significantly from the control group(simulated "free-ranging" condition) in several variables: bonevolume fraction ("linear" 42% less than controls; "turning"24% less than controls), trabecular number ("linear" 12% lessthan controls; "turning" 9% less than controls), connectivitydensity ("linear" 43% less than controls; "turning" 35% lessthan controls), and a characterization of trabecular surfaces("linear" 15% greater than controls; "turning" 11% greater thancontrols). No differences in the degree of anisotropy were observedamong groups, and generally, "linear" and "turning" groups didnot differ significantly from one another in any measures oftrabecular microarchitecture. Considering the distinct differencesin locomotor behaviors between the "linear" quadrupedalism and"turning" groups, these data suggest that comparisons at thedistal femoral metaphysis of trabecular microarchitecture ororientation between different groups of animals may be somewhatlimited in accurately reconstructing the loading conditionsassociated with different locomotor modes.     

Model of head–neck joint fast movements in the frontal plane

The objective of this work is to develop a model representing the physiological systems driving fast head movements in frontal plane. All the contributions occurring mechanically in the head movement are considered: damping, stiffness, physiological limit of range of motion, gravitational field, and muscular torques due to voluntary activation as well as to stretch reflex depending on fusal afferences. Model parameters are partly derived from the literature, when possible, whereas undetermined block parameters are determined by optimising the model output, fitting to real kinematics data acquired by a motion capture system in specific experimental set-ups. The optimisation for parameter identification is performed by genetic algorithms. Results show that the model represents very well fast head movements in the whole range of inclination in the frontal plane. Such a model could be proposed as a tool for transforming kinematics data on head movements in neural equivalent data, especially for assessing head control disease and properly planning the rehabilitation process. In addition, the use of genetic algorithms seems to fit well the problem of parameter identification, allowing for the use of a very simple experimental set-up and granting model robustness.     

Scientific Authority in the Creation–Evolution Debates

At the heart of debates among creationists and evolutionists are questions about scientific integrity and rigor. Creationists often justify their rejection of biological evolution by claiming that the methodologies and interpretations of evolutionary scientists are flawed. A consideration of creationists’ critiques of the scientific data, however, reveals a deficient understanding and appreciation of the nature of the scientific process. It is essential that our schools educate students about the character of scientific inquiry. Clarifying the nature and limitation of scientific knowledge for our students will equip our students to evaluate evolutionary or creationist arguments critically. Recognizing and teaching both the strengths and limitations of the scientific process will do much to further the ongoing dialogue between science and religion.     

Evolution of host resistance to parasite infection in the snail–schistosome–human system

The evolutionary strategies that emerge within populations can be dictated by numerous factors, including interactions with other species. In this paper, we explore the consequences of such a scenario using a host-parasite system of human concern. By analyzing the dynamical behaviors of a mathematical model we investigate the evolutionary outcomes resulting from interactions between Schistosoma mansoni and its snail and human hosts. The model includes two types of snail hosts representing resident and mutant types. Using this approach, we focus on establishing evolutionary stable strategies under conditions where snail hosts express different life-histories and when drug treatment is applied to an age-structured population of human hosts. Results from this work demonstrate that the evolutionary trajectories of host-parasite interactions can be varied, and at times, counter-intuitive, based on parasite virulence, host resistance, and drug treatment.     

Molecular architecture of the Dam1 complex–microtubule interaction

Mitosis is a highly regulated process that allows the equal distribution of the genetic material to the daughter cells. Chromosome segregation requires the formation of a bipolar mitotic spindle and assembly of a multi-protein structure termed the kinetochore to mediate attachments between condensed chromosomes and spindle microtubules. In budding yeast, a single microtubule attaches to each kinetochore, necessitating robustness and processivity of this kinetochore–microtubule attachment. The yeast kinetochore-localized Dam1 complex forms a direct interaction with the spindle microtubule. In vitro, the Dam1 complex assembles as a ring around microtubules and couples microtubule depolymerization with cargo movement. However, the subunit organization within the Dam1 complex, its higher-order oligomerization and how it interacts with microtubules remain under debate. Here, we used chemical cross-linking and mass spectrometry to define the architecture and subunit organization of the Dam1 complex. This work reveals that both the C termini of Duo1 and Dam1 subunits interact with the microtubule and are critical for microtubule binding of the Dam1 complex, placing Duo1 and Dam1 on the inside of the ring structure. Integrating this information with available structural data, we provide a coherent model for how the Dam1 complex self-assembles around microtubules.     

New Developmental Evidence Clarifies the Evolution of Wrist Bones in the Dinosaur–Bird Transition

From early dinosaurs with as many as nine wrist bones, modern birds evolved to develop only four ossifications. Their identity is uncertain, with different labels used in palaeontology and developmental biology. We examined embryos of several species and studied chicken embryos in detail through a new technique allowing whole-mount immunofluorescence of the embryonic cartilaginous skeleton. Beyond previous controversy, we establish that the proximal–anterior ossification develops from a composite radiale+intermedium cartilage, consistent with fusion of radiale and intermedium observed in some theropod dinosaurs. Despite previous claims that the development of the distal–anterior ossification does not support the dinosaur–bird link, we found its embryonic precursor shows two distinct regions of both collagen type II and collagen type IX expression, resembling the composite semilunate bone of bird-like dinosaurs (distal carpal 1+distal carpal 2). The distal–posterior ossification develops from a cartilage referred to as “element x,” but its position corresponds to distal carpal 3. The proximal–posterior ossification is perhaps most controversial: It is labelled as the ulnare in palaeontology, but we confirm the embryonic ulnare is lost during development. Re-examination of the fossil evidence reveals the ulnare was actually absent in bird-like dinosaurs. We confirm the proximal–posterior bone is a pisiform in terms of embryonic position and its development as a sesamoid associated to a tendon. However, the pisiform is absent in bird-like dinosaurs, which are known from several articulated specimens. The combined data provide compelling evidence of a remarkable evolutionary reversal: A large, ossified pisiform re-evolved in the lineage leading to birds, after a period in which it was either absent, nonossified, or very small, consistently escaping fossil preservation. The bird wrist provides a modern example of how developmental and paleontological data illuminate each other. Based on all available data, we introduce a new nomenclature for bird wrist ossifications.     

Fate of the H-NS–Repressed bgl Operon in Evolution of Escherichia coli

In the enterobacterial species Escherichia coli and Salmonella enterica, expression of horizontally acquired genes with a higher than average AT content is repressed by the nucleoid-associated protein H-NS. A classical example of an H-NS–repressed locus is the bgl (aryl-β,D-glucoside) operon of E. coli. This locus is “cryptic,” as no laboratory growth conditions are known to relieve repression of bgl by H-NS in E. coli K12. However, repression can be relieved by spontaneous mutations. Here, we investigated the phylogeny of the bgl operon. Typing of bgl in a representative collection of E. coli demonstrated that it evolved clonally and that it is present in strains of the phylogenetic groups A, B1, and B2, while it is presumably replaced by a cluster of ORFans in the phylogenetic group D. Interestingly, the bgl operon is mutated in 20% of the strains of phylogenetic groups A and B1, suggesting erosion of bgl in these groups. However, bgl is functional in almost all B2 isolates and, in approximately 50% of them, it is weakly expressed at laboratory growth conditions. Homologs of bgl genes exist in Klebsiella, Enterobacter, and Erwinia species and also in low GC-content Gram-positive bacteria, while absent in E. albertii and Salmonella sp. This suggests horizontal transfer of bgl genes to an ancestral Enterobacterium. Conservation and weak expression of bgl in isolates of phylogenetic group B2 may indicate a functional role of bgl in extraintestinal pathogenic E. coli.     

Molecular Evolution of the Photolyase–Blue-Light Photoreceptor Family

The photolyase–blue-light photoreceptor family is composed of cyclobutane pyrimidine dimer (CPD) photolyases, (6-4) photolyases, and blue-light photoreceptors. CPD photolyase and (6-4) photolyase are involved in photoreactivation for CPD and (6-4) photoproducts, respectively. CPD photolyase is classified into two subclasses, class I and II, based on amino acid sequence similarity. Blue-light photoreceptors are essential light detectors for the early development of plants. The amino acid sequence of the receptor is similar to those of the photolyases, although the receptor does not show the activity of photoreactivation. To investigate the functional divergence of the family, the amino acid sequences of the proteins were aligned. The alignment suggested that the recognition mechanisms of the cofactors and the substrate of class I CPD photolyases (class I photolyases) are different from those of class II CPD photolyases (class II photolyases). We reconstructed the phylogenetic trees based on the alignment by the NJ method and the ML method. The phylogenetic analysis suggested that the ancestral gene of the family had encoded CPD photolyase and that the gene duplication of the ancestral proteins had occurred at least eight times before the divergence between eubacteria and eukaryotes. Received: 23 October 1996 / Accepted: 1 April 1997     

Evolution of Defence Portfolios in Exploiter–Victim Systems

Some organisms maintain a battery of defensive strategies against their exploiters (predators, parasites or parasitoids), while others fail to employ a defence that seems obvious. In this paper, we shall investigate the circumstances under which defence strategies might be expected to evolve. Brood parasites and their hosts provide our main motivation, and we shall discuss why the reed warbler Acrocephalus scirpaceus has evolved an egg-rejection but not a chick-rejection strategy as a defence against the common (Eurasian) cuckoo Cuculus canorus, while the superb fairy-wren Malurus cyaneus has evolved a chick-rejection but not an egg-rejection strategy as a defence against Horsfield's bronze-cuckoo Chrysococcyx basalis. We suggest that the answers lie in strategy-blocking, where one strategy (the blocking strategy) prevents the appearance of another (the blocked strategy) that would be adaptive in its absence. This may be common in exploiter–victim systems.     

Desferoxamine protects against glucocorticoid-induced osteonecrosis of the femoral head via activating HIF-1α expression

Glucocorticoid-induced osteonecrosis of the femoral head (GIOFH) is one of the most common complications of glucocorticoid administration. By chelating Fe²⁺, desferoxamine (DFO) was reported to be able to activate the HIF-1α/VEGF pathway and promote angiogenesis. In the present study, we examined whether DFO administration could promote angiogenesis and bone repair in GIOFH. GIOFH was induced in rats by methylprednisolone in combination with lipopolysaccharide. Bone repair was assessed by histologic analysis and microcomputed tomography (micro-CT). Vascularization was assessed by Microfil perfusion and micro-CT analysis. Immunohistochemical staining was performed to analyze the expression of HIF-1α, VEGF, and CD31. Our in vivo study revealed that DFO increased HIF-1α/VEGF expression and promoted angiogenesis and osteogenesis in GIOFH. Moreover, our in vitro study revealed that DFO restored dexamethone-induced HIF-1α downregulation and angiogenesis inhibition. Besides, our in vitro study also demonstrated that DFO could protect bone marrow-derived stem cells from dexamethone-induced apoptosis and mitochondrial dysfunction by promoting mitophagy and mitochondrial fission. In summary, our data provided useful information for the development of novel therapeutics for management of GIOFH.     

Revelation of an enigmatic signaling machinery—First insights into the mammalian TRPC architecture

Canonical TRP channels (TRPCs) are a particularly enigmatic family of signaling molecules with multimodal sensing features, being involved in a wide range of biological functions. Until very recently, the main hurdle towards comprehensive mechanistic understanding of TRPC signaling has been the lack of structural information. This has changed early this year by several reports on TRPC architectures resolved by single particle cryo-EM analysis. These studies confirmed recently elaborated concepts on TRPC structure-function relations, and unveiled unanticipated features and complexity in the TRPC sensing machinery.     

《Review of Diving Beetles of the world》书评

<正>拥有一本某一类群系统的世界性分类鉴定手册,对昆虫分类工作者来说十分重要。在水生甲虫中,龙虱科Dytiscidae是最大的类群,然而一直缺乏一本世界性的鉴定手册。MillerBergsten编著的《世界龙虱》的出版为了解和鉴定龙虱提供了方便。该书为320页的精美硬装本,也有可购买的电子版。该书可分为以下几部分:1.导言:介绍了龙虱的生活史和行为学、