Genes controlling plant development have been studied in multiple plant systems. This has provided deep insights into conserved genetic pathways controlling core developmental processes including meristem identity, phase transitions, determinacy, stem elongation, and branching. These pathways control plant growth patterns and are fundamentally important to crop biology and agriculture. This review describes the conserved pathways that control plant development, using Arabidopsis as a model. Historical examples of how plant development has been altered through selection to improve crop performance are then presented. These examples, drawn from diverse crops, show how the genetic pathways controlling development have been modified to increase yield or tailor growth patterns to suit local growing environments or specialized crop management practices. Strategies to apply current progress in genomics and developmental biology to future crop improvement are then discussed within the broader context of emerging trends in plant breeding. The ways that knowledge of developmental processes and understanding of gene function can contribute to crop improvement, beyond what can be achieved by selection alone, are emphasized. These include using genome re-sequencing, mutagenesis, and gene editing to identify or generate novel variation in developmental genes. The expanding scope for comparative genomics, the possibility to engineer new developmental traits and new approaches to resolve gene–gene or gene–environment interactions are also discussed. Finally, opportunities to integrate fundamental research and crop breeding are highlighted. Arabidopsis thaliana) will be used as a generic model to introduce developmental programs of plants; the blueprints that determine plant size and shape. The focus will be the pathways controlling meristem identity, determinacy, phase transitions, branching and internode elongation. Historic examples that show how these conserved pathways have contributed to crop improvement will then be highlighted. Finally, strategies to harness developmental biology for future crop improvement will be discussed within the context of current trends in plant breeding.An increasing global population requires a 70% rise in food production by 2050 to maintain food security . OpportuFigure 1). This developmental sequence can be divided into three phases of shoot apex meristem identity: (1) vegetative, when apices produce leaves, (2) inflorescence, when an apex contributes to inflorescence growth, and (3) floral, when an apex differentiates into a flower . Phase transitions are triggered by meristem identity genes that determine which organs develop at a shoot apex. For example, the MADS box transcription factors APETALA1 (AP1) and FRUITFULL (FUL) promote inflorescence and floral meristem identity . One mechanism that terminates growth of the primary axis in some plants is the transition of the apical meristem to floral meristem identity, resulting in the production of a terminal flower. The TERMINAL FLOWER1 (TFL1) mutant of Arabidopsis produces a terminal flower and so exhibits determinate growth of the primary axis (TFL1 encodes a poly-ethanolamine lipid binding protein (PEPB) that normally represses AP1 expression at the shoot apical meristem  or can terminate (determinate). The primary shoot apex of Arabidopsis normally grows indeterminately, first vegetatively, then as an inflorescence meristem that never undergoes the transition to floral development . Specific examples from tomato (Lycopersicon esculentum) and bread wheat (Triticum aestivum) will be presented later to illustrate how the conserved meristem identity functions of these genes have been utilized in crop improvement.monocots . These gmonocots . Conservmonocots . The conFigure 1)  .Pisum sativum) show that decapitation also leads to increased sucrose in axillary buds (BRANCHED1 (BRC1) gene of Arabidopsis. BRC1 encodes a transcription factor that inhibits both the formation of axillary meristems and bud outgrowth . Elongation is driven by expansion of cells produced by the shoot apical meristem and by production of additional cells above nodes . The respective contribution of cell elongation versus cell division differs between plant species. The plant hormone gibberellic acid (GA) regulates internode elongation (see Internode elongation influences stem and branch length (tion see . Bioactition see . Other htion see .BRC1-type genes was conducted in maize (Zea mays). The ancestor of modern maize, teosinte , produces many lateral branches, whereas modern cultivars typically produce a single main stem allowing high-density cultivation and increased crop yields per unit area (see TEOSINTE BRANCHED1 (TB1), the maize equivalent of Arabidopsis BRC1 and this is a classic example of a developmental gene that facilitated domestication of a crop , which encodes a MADS box transcription factor that is expressed at high levels before winter and blocks the transition to reproductive development  gene (CO is regulated by the circadian oscillator and peaks in the afternoon (FLOWERING LOCUS T (FT) in the leaves  gene . Transcrfternoon . When dafternoon . CO thene leaves . FT encoidentity . FT can identity . Transcro winter .CO-FT” day-length response pathway. For example, the rice CO-like gene HEADING DATE1 (HD1) gene of rice (Oryza sativa) plays an important role in regulating photoperiodic induction of FT-like genes but is unlikely to be a direct equivalent of the CO gene of Arabidopsis . Examples that highlight how developmental genes have been used to reprogram crop growth patterns to maximize yield potential and to suit modern cultivation practices are presented in the following sections.Developmental pathways are fundamental determinants of crop yield. This point is illustrated by the harvest index concept, which states that the yield of a crop under ideal growing conditions  is set by the proportion of plant biomass that is converted into a harvestable product see . AccordiTomato exhibits sympodial growth . The priSP gene disrupt sympodial growth such that each successive sympodial unit transitions more rapidly to floral meristem identity, producing progressively fewer leaves until sympodial growth ceases  is the tomato ortholog of FT  gene. This gene encodes an oxidase enzyme (GA20ox-2) that is required for GA biosynthesis (SD1 lead to lowered bioactive GA levels and reduced plant height. The main driver of semi-dwarf stature in bread wheat is REDUCED HEIGHT 1 (RHT1), which encodes the wheat DELLA protein . VRN1 promotes the transition to reproductive development and is related to AP1 and FUL MADS box transcription factors of Arabidopsis , a component of the circadian clock . This shows that the model for daylength sensing developed in Arabidopsis, that circadian clock regulation of CO allows daylength specific activation of FT, is broadly relevant to crop species. There is likely to be more to this story, however. There are other daylength-induced floral promoters in some species, gibberellins in cereals for example (Fragaria vesca) a TFL-like gene acts as a daylength specific repressor of flowering  breeding. There are three dwarfing genes in peach, DWARF  (dw gene is linked to loss-of-function mutation in a gene encoding a GA receptor (BROOMY” (br), has been identified  . The dw receptor . Similarentified . IdentifThere are alternative marker-assisted selection approaches that do not require detailed knowledge of developmental biology. The use of high-density Single Nucleotide Polymorphism (SNP) marker arrays is becoming routine in crop breeding programs. SNP markers can be used as anonymous indicators of performance and developmental traits can be tracked and selected by linked SNPs or multi-SNP haplotypes . This doFT-like genes   e.g., . As the mes e.g. .Table 1 and Figure 3). Additionally, there is scope for novel mutations (or genes) to influence the activity of conserved developmental pathways when comparisons are made across diverse plants, since factors like genetic redundancy can vary between species.Diversity collections can also be used as a platform to identify diversity in crop developmental genes via Genome-Wide Association Studies (GWAS). This has proven to be an effective strategy for mapping genes controlling developmental traits in important crops including maize, rice, barley, and wheat e.g., . GWAS caELF3 loss-of-function mutations, versus mutations that influence more specific clock outputs, such as recessive alleles of the PHOTOPERIOD1 (a PRR73 gene) that alter daylength responses with less impact on overall clock function  or different linkage relationships with other traits. Moreover, different genes in a developmental pathway can have different trade-offs with other aspects of crop performance. For example, there is potential to identify cereal clock gene mutations that influence broad aspects of daily rhythms, such as function .FT1 gene slow meristem phase-transitions in the spike and enhance the formation of paired spikelets, where two spikelets form at inflorescence nodes instead of the normal single spikelet , suppress branch outgrowth from inflorescence nodes (Table 3) has a conserved role in suppressing inflorescence branching in maize, rice, barley, and wheat, and loss-of-function mutations in this transcription factor generate highly branched inflorescences in each of these cereals  architecture in cereals. These genes determine the extent to which lateral branch meristems develop at nodes of the inflorescence. For example, low transcript levels of the wheat spikelet . Other gce nodes . An AP2/ cereals . Inflore cereals .Table 4). These highlight a number of molecular mechanisms that can be targeted by reverse genetics to engineer crop development. Three examples of ways that reverse genetics can be applied to crop developmental biology are discussed below.There is potential to move beyond the scope of natural variation by applying reverse genetics. Before considering potential applications of reverse genetics to the developmental biology of crops, it is important to consider the genetic architecture of developmental traits. So far the main focus of this review has been simple developmental traits that are controlled by limited numbers of genes. These traits are ideal targets for reverse genetics since altering the activity of a single gene can trigger large phenotypic changes. More complex developmental traits are also important but are less attractive as initial targets for reverse genetics. These will be discussed later. Another important consideration is the nature of functional variation that give rise to developmental traits. Historical examples include loss or gain-of-function mutations, of varying strengths . For most wheat genes there is redundancy between the three genomes, so loss-of-function mutations are unlikely to impact phenotype and be selected by traditional breeding methods. For example, loss-of-function mutations in gibberellin biosynthesis genes that give rise to semi-dwarf stature would have been difficult to deploy in wheat. Access to genome sequences, combined with “TILLING  by sequencing” allows efficient identification of loss-of-function mutations on all three wheat genomes, which can then be stacked in single line using corresponding molecular markers . This apAP2-like and SQUAMOSA-PROMOTER BINDING PROTEIN-like (SPL) gene families, are regulated by microRNAs that bind to target sites in mRNAs and trigger transcript cleavage (reviewed in Q gene has a 21 bp target site for microRNA172 (miR172)  or compact spikes  . Mutatiohability . Mutatiot spikes . Similarin yield .SFT activity in tomato can optimize developmental patterns to maximize yield . Hybrid vigor, where the progeny of an inter-cross out-performs either parent, is often applied by plant breeders to increase crop yields. If developmental patterns and plant architecture are critical to increasing plant yield then one prediction is that genes controlling plant development should contribute to hybrid vigor. There is evidence this is the case. Heterozygosity at itecture . Similar hybrids . This ra hybrids .VRN1 gene of wheat and barley influences root development, in addition to regulating reproductive development, highlights the potential for genes that influence above ground development to have pleiotropic effects on root architecture . Subsequent discussion will focus on three specific areas; dissecting developmental components of yield potential, resolving pleiotropy, and optimizing development to maximize potential yield for specific target environments.Modern breeding programs typically shuffle variation in large numbers of genes controlling multiple traits, spanning from yield potential, stress tolerance, disease resistance to end-use quality. One question that has not yet been addressed is whether knowledge of developmental biology can be harnessed to accelerate the rate of yield gain in the complex context of plant breeding. Knowledge of developmental gene function can influence several factors that determine the rate of genetic gain in a breeding program . The genetic basis of these subcomponent traits can be resolved. For example, the genetic architecture of phenology is well understood in several crops, including maize, wheat, rice, barley, legumes and canola, and there is deep knowledge of the overall molecular pathways and genes controlling specific yield subcomponents of some crops . For example, variation that accelerates the transition to reproductive development of wheat can lead to fewer inflorescences per plant, and thus lower grain/seed yield . An improved understanding of how gene-environment interactions influence crop development can allow developmental patterns to be optimized for specific target environments. One specific area that warrants further research is developmental responses to higher ambient temperature. Increasing temperatures influence crop developmental patterns, typically accelerating flowering and reducing yield . CurrentAs crop breeders begin to apply genotyping-by-sequencing there will be opportunities for plant breeding to be closely linked with genome biology research. For example, training populations used in genomic selection programs can be used for gene mapping. Breeding pedigrees can also be used for gene mapping, as illustrated by autozygosity mapping in human genetics where homozygosity for allelic variation within a pedigree can be used to locate chromosomal regions carrying a genetic disease see . A closeWith sufficient understanding of crop biology it will be possible to integrate gene and environment information to predict overall developmental behavior and flow-on effects to other traits. Models that predict flowering dates for specific crops at particular sites are already used as management and research tools, such as Agricultural Production Systems sIMulator (APSIM) . A futurDevelopmental pathways control patterns of plant growth that determine crop yield. Historical examples highlight the transformative impact that variation in developmental genes has had on crop performance. Now, with increased understanding of conserved pathways controlling plant development and access to crop genome sequences, diversity in genes controlling development can be rapidly and efficiently channeled into crops. This is paralleled by emerging reverse-genetics technologies that offer new ways to harness developmental biology for crop improvement. Applying these advances in plant developmental biology to crop breeding will contribute to increasing crop yields to meet future demand.The author confirms being the sole contributor of this work and approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Clozapine is known to cause fecal impaction and ileus with resultant colonic necrosis due to compression of colonic mucosa. There are rare reports of clozapine causing necrosis of other portions of the gastrointestinal tract unrelated to constipation. We describe a case of acute necrosis of the upper gastrointestinal tract and small bowel to due to clozapine and quetiapine.A 66-year-old white man with a past medical history of schizophrenia, maintained on clozapine and quetiapine, presented with hypoxic respiratory failure caused by aspiration of feculent emesis due to impacted stool throughout his colon. His constipation resolved with discontinuation of clozapine and quetiapine, and his clinical condition improved. These medicines were restarted after 2 weeks, resulting in acute gastrointestinal necrosis from the mid esophagus through his entire small bowel. He died due to septic shock with Gram-negative rod bacteremia.Clozapine may cause acute gastrointestinal necrosis. Constipation is a common side effect of antipsychotic medicines, and is attributed to their anticholinergic properties . ConstipEscherichia coli and Klebsiella oxytoca. Surgical consultation was obtained, but no surgical intervention was possible given the widespread gastrointestinal involvement and his moribund state. He died within 24 hours of developing symptoms. An autopsy was declined.A 66-year-old white man with a history of schizophrenia presented to our emergency department with acute altered mental status and feculent emesis. His abdomen was distended but not tender. He was found to be in severe respiratory distress requiring endotracheal intubation, and shock requiring vasopressor infusion. Computed tomography (CT) imaging revealed acute respiratory distress syndrome (ARDS) due to aspiration as well as impacted stool throughout his colon. Home antipsychotic medicines, clozapine and quetiapine, were held, and after manual disimpaction and enemas he had copious bowel movements and resolution of abdominal distension. His shock and ARDS gradually improved. Vasopressors were discontinued on day 3, and he remained normotensive. In-patient medicines were carbamazepine, lansoprazole, phenytoin, polyethylene glycol, senna, and subcutaneous heparin prophylaxis. Clozapine 100 mg every 12 hours was restarted on day 11, and a single dose of quetiapine 400 mg was given on day 16, both at home doses. Six hours after quetiapine was restarted, he was noted to have recurrence of abdominal distension and new onset of copious foul-smelling hematemesis. An abdominal X-ray showed diffuse small bowel dilation Fig. , with coOur patient’s initial presentation with aspiration of feculent emesis due to impacted stool throughout the colon is within the known spectrum of life-threatening clozapine-induced colonic hypomotility. Fecal impaction resolved with discontinuation of clozapine and quetiapine.Acute gastrointestinal necrosis developed 5 days after restarting clozapine and 6 hours after restarting quetiapine. EGD and abdominal X-ray were consistent with necrosis from the mid esophagus through the entire small bowel. His new onset foul smelling hematemesis, abdominal distension, and polymicrobial Gram-negative rod bacteremia clinically matched imaging findings, and he died within 24 hours of developing symptoms. Given the temporal association with his clinical deterioration, we believe his acute gastrointestinal necrosis was caused by re-initiating clozapine and quetiapine.Other causes of gastrointestinal necrosis were considered. It is unlikely that proximal splanchnic arterial occlusion from embolic or other source occurred, as necrosis was present in multiple vascular territories. Our patient had remained off vasopressors with normal blood pressure for 13 days, making a shock state an unlikely cause. His other medications did not include vasoactive drugs known to cause mesenteric ischemia such as alpha agonists, digoxin, or ergotamines .et al. in 2013 reported a case of a 47-year-old man who developed acute necrosis of small bowel and colon 6 days after initiating clozapine [There are few reports of clozapine causing acute necrosis of portions of the gastrointestinal tract other than the colon. Yu 3 (5-HT3) serotonin receptor [3 inhibiting drug used to treat irritable bowel syndrome with diarrhea, was withdrawn from the market due to causing ischemic colitis unrelated to constipation, and was subsequently reintroduced with a black box warning [A possible mechanism of clozapine-induced acute gastrointestinal necrosis is antiserotonergic effect. Clozapine is the only antipsychotic medicine known to be a competitive inhibitor of the 5-hydroxytryptaminereceptor . Alosetr warning , 10.Clozapine is known to cause fecal impaction and ileus, compressing the colonic mucosa and leading to colonic necrosis. Two recent cases have described clozapine-induced acute necrosis of the small bowel and upper gastrointestinal tract, without constipation. We present a third such case. Further monitoring is needed to confirm this suspected life-threatening side effect of clozapine.


Patients who develop osteosarcoma in 2017 receive treatment that remains essentially unchanged since the 1970s. Outcomes likewise remain largely unimproved. Large, collaborative, multinational efforts to improve therapy have evaluated strategies leveraging both cytotoxic intensification and immunomodulatory agents. While these have confirmed our capacity to conduct such trials, results have proved largely disappointing. This has motivated efforts to focus on the basic biology of osteosarcoma, where understanding remains poor but has improved significantly. Recent advances have identified characteristic genetic features of osteosarcoma, including profound chromosomal disruption, marked patient-patient heterogeneity, and a paucity of recurrent mutations. Analyses suggest genesis in early catastrophic genetic events, although the nature of the inciting events remains unclear. While p53 and Rb inactivation occurs in most osteosarcomas, the landscape of associated driver mutations has proved extensive. Few mutations recur with high frequency, though patterns continue to emerge that suggest recurrent alterations within specific pathways. Biological pathways implicated in osteosarcoma biology through genetic and other preclinical studies include PI3K/mTOR, WNT/βcatenin, TGFβ, RANKL/NF-κB, and IGF. Unfortunately, clinical studies evaluating targeted agents have to date yielded disappointing results, as have studies examining modern immunotherapeutics. It remains unclear whether this pattern of clinical failures exposes inadequacies of our preclinical models, unrealistic expectations for single-agent responses in heavily pretreated patients, or biology less relevant than suggested. Nearly all patients who succumb to osteosarcoma develop lung metastases, which exhibit marked chemoresistance. Much scientific effort has recently sought to enhance our mechanistic understanding of metastasis biology. This research has potential to reveal novel targets for preventing and treating metastasis and for uncovering key vulnerabilities of osteosarcoma cells. Efforts to implement drug development strategies that leverage clinical studies in veterinary patients have potential to accelerate the translation of novel experimental regimens toward human studies. These could reduce costs and development timelines, prioritize agents, and refine regimens prior to human clinical trials. The rise of philanthropic groups focused on osteosarcoma has enhanced cross-disciplinary and cross-institutional focus and provided much needed resources. Transformative new therapies will likely arise from collaborative, interdisciplinary efforts that extend our understanding of osteosarcoma’s most basic inner workings. Children diagnosed with cancer today benefit from years of incremental advances in therapy that have reduced childhood cancer mortality by over 50% since the mid-1970s  and chemChildren and adolescents diagnosed with osteosarcoma have not experienced similar advances. Those diagnosed with osteosarcoma in 2017 receive medical therapies that remain essentially unchanged since the introduction of MAP  in the late 1970s . OutcomeThose who develop metastatic disease continue to experience dismal outcomes; development of pulmonary metastasis heralds the onset of chemoresistance and a pivot toward more experimental therapies, given the lack of hope offered by currently established therapies. Prognosis remains poor whether metastases develop prior to diagnosis or long after completing therapy . 5-year Patients diagnosed today clearly benefit from advances made in both the surgical treatment of disease and in the provision of supportive care. Limb-sparing methods pioneered in canine patients with osteosarcoma  have becIn this review, we briefly outline several emerging discoveries that advance the known biology of osteosarcoma as well as several ongoing initiatives that offer hope for the future. We highlight and discuss several aspects of osteosarcoma biology that suggest opportunities where improvements in our understanding of the underlying biology might lead to meaningful therapeutic advances. These include: the molecular biology of osteosarcomagenesis, mechanisms that drive pulmonary metastasis, and a rapidly evolving understanding of the interface between immunology and oncology. We will also highlight two broad initiatives that promise to enhance our ability to affect change, namely the rapidly growing availability of well-characterized models of disease and the organization of advocacy groups that push science forward and fill much-needed philanthropic niches to make that science possible.Transformative advances in the treatment of osteosarcoma will likely emerge from insights into the mechanistic biology that underlies the disease. Large-scale efforts to characterize the genomic landscape of osteosarcoma have revealed a genome characterized by marked inter- and intra-tumoral heterogeneity, chains of complex chromosomal rearrangements, widespread gene copy number alterations, and localized regions of hypermutation –18. UnbiThese analyses support several long-suspected hypotheses. They demonstrate near-universal loss of p53 through a number of mechanisms and frequent alterations of Rb , 18, 19.Smaller-scale hypothesis-driven investigations have suggested roles for other pathways in the progression of osteosarcoma. WNT/β-catenin pathway activation appears to drive some characteristics of proliferation and early metastasis –24. AberTumor–host interactions appear critical to the development of osteosarcoma. Some of these microenvironmental factors have been identified, including stromal-derived TGFβ  and IL6 One of the most clinically relevant applications of this molecular biology work comes from identification of pathways responsible for chemoresistance. A number of studies hint at mechanisms of resistance, most notably that arising from activation of the PI3K/Akt/mTOR pathway , 32, 33.Unfortunately, among all preclinical work suggesting efficacy with targeting of these pathways, few invoke more than growth delays, making their potential clinical utility suspect. This could result because (1) these do not represent major driver pathways of the disease, (2) redundancies and escape/resistance mechanisms exist, which render these targeting methodologies ineffective, or (3) these pathways drive biology in a subset of tumor cells within a heterogeneous tumor. Regardless of the reason, advances will not likely come from single-pathway targeting, but from identifying synthetic lethalities resulting from specific combinations.Recent reports detail intriguing patterns of gene copy number variation in OS, suggesting that the chaotic chromosomal rearrangements of OS might lead naturally to amplification of oncogenes or loss of tumor suppressors that drive malignant progression . These rMetastasis remains the most important fatal complication of osteosarcoma. Among those who develop metastasis, less than 1 in 5 survive . A theraSeveral of the molecular mechanisms identified as driver pathways in OS clearly play key roles in the metastatic cascade. WNT/β-catenin pathway activation likely facilitates early steps, including invasion, chemotaxis, and extravasation , 24, andΔNp63-derived IL6 and CXCL8 produced by tumor cells clearly play key roles in lung colonization. Gene manipulation studies suggest that targeting these processes could block metastasis , 42. CliThe relatively slow pace for identification of specific mechanisms that effect metastasis highlights some of the challenges inherent to this type of research. Several of the most recent developments, however, identify mechanisms that not only appear to represent real metastatic dependencies but can also be targeted using existing therapeutics . While mSome have suggested that the genomic complexity of osteosarcoma may divulge a sensitivity to immunotherapy . EffortsUnfortunately, this hope has not yet translated into robust clinical benefit. The EURAMOS-1 trial randomized a large number of good histologic responders to maintenance with or without interferon α2b, but failed to demonstrate benefit . The othMore recent efforts seek to capitalize on the successes seen with immune checkpoint inhibitors in other cancers by extending those regimens to patients with osteosarcoma. Expression of checkpoint molecules like PD-L1 on osteosarcoma cells correlates with metastasis and decreased survival , 51, andInvestigators worldwide have generated, developed, and characterized an ever-growing number of models that researchers can leverage in the study of osteosarcoma. Numerous cell lines  provide Some question how well these models represent the true intrinsic biology of the human disease , 62. CelEvaluating biology and novel therapeutic strategies using selected libraries of PDX tumors can overcome limitations inherent to more common traditional approaches , 68. WhiPatient-derived xenografts models poorly address several increasingly relevant aspects of tumor biology. Most of these limitations stem from the need to utilize immunodeficient mice in the passaging of human tumors, making study of immune-based therapies and other tumor–host interactions difficult. The emergence of systems and science around comparative oncology has great potential to address these shortcomings , 70. Thivice versa (Biologically, canine osteosarcomas appear nearly indistinguishable from the human disease. The study of disease in one species will likely benefit the other, and ce versa , 73–76. ce versa .The study of naturally occurring osteosarcoma in pet dogs has particular relevance to the study of immune-based therapies. In dogs, disease develops in the context of an intact immune system and accurately models the complex biology of the cancer microenvironment . RecogniWhile metastasis and development of resistance represent the biological processes most important to clinical outcomes, these are poorly modeled in most of the assays routinely used for preclinical development of novel therapeutics. Ideally, preclinical investigation will reveal specific, actionable targets that lead to an initial focused screening. Models exist, which can facilitate validation of these candidates, as well as more broad-based screening of small libraries, though doing so remains cumbersome and comes with a number of biological caveats . The incThe emergence of innovative and organized philanthropic and advocacy groups with strong disease focus has catalyzed movement around several recent initiatives. Their engagement provides not only badly needed funding but their relative detachment from the worlds of academia and industry allows them to foster collaborations and address systemic needs that lack incentive within those communities. Not content to limit their roles to advocacy and education, these groups have overseen the organization and annotation of large tissue banks, including osteosarcoma , 79. TheDevelopment of novel therapies for osteosarcoma has suffered a discouraging past. Our maturing understanding of some fundamental aspects of osteosarcoma biology Figure , coupledThis confluence of scientific and supportive developments leads many physicians and scientists to a hopeful anticipation that transformative discoveries might lie upon a very near horizon. One might argue that the future, in fact, looks very bright. With our patients in mind, we hope that this quickening pace of discovery will translate into real clinical advances for patients who need better options now.AS, JF, and RR all contributed to the design, drafting, revision, and final approval of this manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Stool microbiota profiling was performed, while functional prediction was done using PICRUSt. Stool short-chain fatty acid (SCFA) metabolites were measured. Histone acetylation and expression of SCFA butyrate receptor were assessed. We found that SCFA-producing bacteria were lower in the polyposis mice, suggesting a decline in the fermentation product of dietary fibers with polyposis. Next, a high fiber diet was given to polyposis mice, which significantly increased SCFA-producing bacteria as well as SCFA levels. This was associated with an increase in SCFA butyrate receptor and a significant decrease in polyposis. In conclusion, we found polyposis to be associated with dysbiotic microbiota characterized by a decline in SCFA-producing bacteria, which was targetable by high fiber treatment, leading to an increase in SCFA levels and amelioration of polyposis. The prebiotic activity of fiber, promoting beneficial bacteria, could be the key mechanism for the protective effects of fiber on colon carcinogenesis. SCFA-promoting fermentable fibers are a promising dietary intervention to prevent CRC.Epidemiological studies propose a protective role for dietary fiber in colon cancer (CRC). One possible mechanism of fiber is its fermentation property in the gut and ability to change microbiota composition and function. Here, we investigate the role of a dietary fiber mixture in polyposis and elucidate potential mechanisms using TS4Cre × cAPC Colon cancer (CRC) is the second leading cause of death from cancer. Although genetic susceptibility plays an important role in the pathogenesis of CRC, environmental factors play an even bigger role in the development of colon cancer. Indeed, multiple observational and epidemiological studies have demonstrated that CRC is closely associated with lifestyle and it is estimated that almost half of CRCs are preventable by a healthy lifestyle ,2. AmongFibers are indigestible in the gastrointestinal tract until arrival to the colon, where they are mainly fermented, resulting in the formation of short-chain fatty acids (SCFA) such as acetate, propionate, and butyrate (in a ratio of 3:1:1 approximately). Several anti-cancerous mechanisms have been shown for SCFAs, including their direct effects on cancerous epithelial cells, or anti-inflammatory effects in the colon as reviewed elsewhere ,6.Fermentation of the fiber in the colon is performed by the colonic microbiota. Therefore, in addition to the amount of fiber intake, varying microbiota may have differential effects on the fermentation ability of fiber, and could potentially modulate the risk of CRC. In this regard, several human studies have linked colonic microbiota to colon carcinogenesis ,8. HowevThe existing discrepancies could be partly explained by factors related to the type of animal model employed to represent human CRC, and/or considerations given to microbiota ,13,14. TAPC) gene are found in the majority of human CRC. To model CRC in this study, we chose TS4Cre × cAPCl°×468 mice (TS4/APC), which are double heterozygous mice with deletion of the adenomatous polyposis coli gene (APCΔ468) in the colonic epithelium. These TS4/APC mice are generated by crossing LoxP APCΔ468 mice with TS4Cre mice that harbor a Cre gene under the control of the fatty acid binding protein 1 (FABP1) gene promotor, restricted to the epithelial cells of the colon and terminal ileum, as previously described  (p_Bacteroidetes) and Lactobacillus (p_Firmicutes). Significant changes in all SCFA metabolites and microbiota are listed in We then correlated the microbial composition with SCFA metabolites. We observed a significant positive correlation between high fiber-fed mice and the genera oidetes) . The posHigher abundance of specific taxa capable of SCFA production prior to polyposis has been shown to be associated with decreased tumor burden in rodents . Here, wSCFAs can exert their effects on colon carcinogenesis through two major pathways—signaling through their receptors or intracellular distribution—resulting in histone deacetylase inhibition (HDACi) ,59,60; tIn order to determine the main potential molecular pathway underlying the observed protective effect of SCFA-promoting fiber on polyposis, we compared the histone acetylation levels as an estimate of histone deacetylase inhibitor (HDACi) capacity of SCFA, in high fiber-treated and untreated mice. Histone acetylation, as estimated by the expression level of PanH3ac (Histone H3ac pan-acetyl), an estimate of HDACi capacity between high fiber and chow-fed mice, was not affected by fiber treatment B, makingWe then compared the expression of the butyrate-specific receptor, GPR109a , in highColon cancer (CRC) is closely linked to lifestyle-associated factors including diet. Dietary fiber has been shown to reduce CRC risk by several epidemiological studies ,4. FermeThe APC mutation and loss of function of the APC gene product is an early and frequent event in human CRC. APC(+/Min) models in rodents show extensive polyposis which almost ubiquitously involves the small bowel, whereas adenoma or adenocarcinoma in human small bowel is a very rare event. Here, we model human CRC using TS4/APC mice that develop polyps mainly in the large bowel. TS4/APC animals are created from the C57BL/6J (B6) strain. In our study, the initial comparison of microbiota was made between these two groups from the same strain.Bacteroides fragilis that belongs to Bacteroidetes has been repeatedly shown to be associated with colorectal neoplasms and to promote CRC [Bacteroides in TS4/APC mice. Additionally, within our study, the genus Desulfovibrio was associated with polyposis. Desulfovibrio is a sulfate-reducing bacteria with pro-inflammatory capacities [Desulfovibrio can colonize, utilize and degrade the colonic mucin layer, and could induce barrier dysfunction [Desulfovibrio has been recently reported in another animal model of CRC [Firmicutes and Bacteroidetes are the two major bacterial phyla that comprise the majority of the normal gut microbiota of healthy humans. Proteobacteria and Actinobacteria constitute the remaining 10% of the microbial system . Similarmote CRC . We alsopacities . Desulfofunction , a phenofunction . Increasl of CRC .An altered ratio of Firmicutes and Bacteroidetes has been associated with a variety of pathologies associated with aging . In an ABifidobacterium and both butyrate-producing clostridial cluster XIVa bacteria Lachnospiraceae unclassified and Anaerostipes. These three putative beneficial gut microbial taxa have been shown to be diminished in colorectal cancer [Bifidobacteria is important to gut health as it has been shown to inhibit enteropathogens and promote gut health by interacting with butyrate-producing bacteria by cross-feeding interactions within the colon [Bifidobacterium has also exhibited protected effects in several cancer cell lines [Lachnospiraceae unclassified and Anaerostipes are believed to benefit the host’s gut barrier functions through anti-inflammation, anti-tumorigenesis, and pathogen exclusion in the colon [SCFAs are the main metabolites of microbial fermentation of fiber, a potential protective diet against CRC according to epidemiologic studies. Based on reduced SCFA-producing bacteria and the potential decline in the fermentation product of dietary fibers in polyposis mice, we targeted microbiota composition by feeding polyposis mice with a high fiber regimen. This intervention increased SCFA-producing bacteria in polyposis mice. Particularly, the high fiber treatment significantly increased the relative abundances in both acetate-producing bacteria l cancer . Bifidobhe colon ,73,74. Bll lines . Additiohe colon ,76,77.Increase in SCFA-producing bacteria resulted in the augmentation of butanoate and propanoate metabolism pathways upon high fiber treatment in our study. Direct measurement of SCFA metabolites confirmed the increase in SCFAs. A high fiber diet in humans has been shown to be associated with improved levels of SCFAs and reduced overall risk of CRC . An incrSeveral mechanisms have been proposed to underlie the anti-cancerous mechanisms of SCFAs ,6. SCFAsOur data, along with other accumulating evidence, suggests fiber intervention as an effective and safe approach for microbiota reprograming to reduce colon tumorigenesis . Our finIn summary, we showed that favorable effects of microbiota-directed intervention on polyposis are likely mediated via gut microbial functionality, mainly through SCFA production . Overall


Sudden infant death syndrome (SIDS) continues to be a major public health issue. Following its major decline since the “Back to Sleep” campaign, the incidence of SIDS has plateaued, with an annual incidence of about 1,500 SIDS-related deaths in the United States and thousands more throughout the world. The etiology of SIDS, the major cause of postneonatal mortality in the western world, is still poorly understood. Although sleeping in prone position is a major risk factor, SIDS continues to occur even in the supine sleeping position. The triple-risk model of Filiano and Kinney emphasizes the interaction between a susceptible infant during a critical developmental period and stressor/s in the pathogenesis of SIDS. Recent evidence ranges from dysregulated autonomic control to findings of altered neurochemistry, especially the serotonergic system that plays an important role in brainstem cardiorespiratory/thermoregulatory centers. Brainstem serotonin (5-HT) and tryptophan hydroxylase-2 (TPH-2) levels have been shown to be lower in SIDS, supporting the evidence that defects in the medullary serotonergic system play a significant role in SIDS. Pathogenic bacteria and their enterotoxins have been associated with SIDS, although no direct evidence has been established. We present a new hypothesis that the infant’s gut microbiome, and/or its metabolites, by its direct effects on the gut enterochromaffin cells, stimulates the afferent gut vagal endings by releasing serotonin (paracrine effect), optimizing autoresuscitation by modulating brainstem 5-HT levels through the microbiome–gut–brain axis, thus playing a significant role in SIDS during the critical period of gut flora development and vulnerability to SIDS. The shared similarities between various risk factors for SIDS and their relationship with the infant gut microbiome support our hypothesis. Comprehensive gut-microbiome studies are required to test our hypothesis. Sudden infant death syndrome (SIDS) is defined as a sudden unexplained death in the first year of life in a previously healthy infant, where the cause of death remains unidentified despite thorough investigations including a complete autopsy, death scene investigation, and review of clinical history . SIDS isSudden infant death syndrome is a condition without a widely accepted singular pathological mechanism.(1)Triple-risk model: this model proposes that SIDS occurs when external stressors simultaneously act upon on a susceptible infant with a vulnerable homeostatic system during a critical developmental period (l period .(2)Failed autoresuscitation: animal studies have shown that cardiorespiratory, sleep, and arousal mechanisms are abnormal following exposure to risk factors associated with SIDS or in infants who later succumb to SIDS Medullary serotonergic network deficiency: SIDS is associated with multiple serotonergic defects including serotonin deficiency (−/−) have major defects in autoresuscitation, a life-preserving process utilized by neonatal mammals in severely hypoxic conditions (ficiency –19. It hficiency –23. Geneficiency . In a reficiency . Recent ficiency . Abnormaficiency . In a sificiency . Cummingnditions –33.(4)Neurotransmitters: neurotransmitter systems  have been shown to be involved in SIDS , relay through nodose and dorsal root ganglia before synapsing with second-order neurons in the spinal cord, which in turn project into the brainstem. The brainstem has major respiratory neurons concentrated into three recognizable groups comprised of four major nuclei. These include the following: (1) dorsal respiratory group (DRG) centered in the NTS; (2) ventral respiratory group that encompasses the nucleus ambiguous and the nucleus retroambigualis; (3) pre-Botzinger complex (pre-BotC) which contains putative pacemaker neurons; and (4) BotC located in and near the nucleus retrofacialis. The DRG neurons through the phrenic neurons in the cervical spinal cord control the diaphragm.The medullary serotonergic system projects to brainstem cardiorespiratory nuclei (including the DMNV), cerebellum, and spinal cord, thus modulating cardiorespiratory protective reflexes, central chemoprotective reflexes, arousal/sleep cycles, thermoregulatory reflexes, and maintenance of upper airway patency .Vagal afferents affect respiratory control as shown by altered respiratory pattern after stimulation of visceral vagal afferents in guinea pigs which died within a few hours of bilateral vagotomy; their frequency of breathing significantly decreased within minutes of the procedure , 65. SerThere is emerging evidence from animal and clinical studies on the role of gut microbiome in CNS signaling.Evidence from rodent studies indicates that the gut microbiome can affect neural development, chemistry, and behaviors, e.g., emotion, pain perception, and stress responses. As rodent gut colonization pattern is similar to humans, they are subjects of choice for gut microbiome studies. CNS tryptophan concentrations are dependent on peripheral content, which suggests that gut flora might play a part in regulating peripheral and central serotonin synthesis , 80, 81.Clostridium spp. in autism  gut flora interacts with ECC and modulates (possibly by its serotonin and other paracrine effects) through the afferent vagal endings to the brain stem medullary serotonergic cardiorespiratory centers in infants at risk for SIDS. Recent research in microbiome–gut–brain axis supports role of probiotics to modulate central brain neurochemistry, thus opening up a site for therapeutic targeting for central brain disorders.In the following section, we report how each of the protective as well as risk factors for SIDS seems to offer evidence of promoting symbiotic (favorable) and dysbiotic gut (non-favorable) flora, respectively, during the critical window when both SIDS tends to occur and early infant gut colonization is being established.(1)Ethnicity: studies in indigenous populations have reported a higher SIDS rate compared to the non-indigenous groups within the same countries (Lactobacillus plantarum (which produce methane and is protective against dysbiosis) (ountries . These dountries . Maternaountries . A recensbiosis) , 101.(2)Low socioeconomic status: SIDS has been associated with lower socioeconomic groups Gender: SIDS shows a male preponderance. Animal studies have shown gender differences in the regulation of serotonergic system Genetic control: genes regulating serotonergic network, brain function and development, and cardiac function play an important role in SIDS Maternal smoking: SIDS is five times more common in infants born to mothers who smoked during pregnancy and three times more common in those exposed postnatally to smoking Being overweight: overweight infants and mothers have a higher risk of SIDS Delivery route: infants delivered by cesarean section have an increased risk of SIDS than those born by vaginal route Season: SIDS is more common during winter months (via microbiome–gut–brainstem pathway.r months . There ir months . Stressor months . Such dy(2)Low birth weight: the rate of SIDS is higher in low birth weight infants Prone sleep position: prone sleeping position has been the most important risk factor associated with SIDS Breastfeeding: breastfeeding has been shown to be protective against SIDS Elevated or reduced room temperature: overheating of infants has been reported with an elevated risk of SIDS Pacifier use: pacifier sucking has been shown to be strongly associated with the oral colonization of salivary lactobacilli Sleep surface, bedding, and stuffed toys: apart from mechanical suffocation and overheating issues, these may act as fomites contributing to the infant gut flora. Sherburn et al. showed that simulated infant head movements and mattress-related factors affect aerial release of bacteria from beds (rom beds .(8)Co-sleeping: recent meta-analyses showed that bed sharing during sleep increases the risk of SIDS, which is further increased when combined with parental smoking, maternal alcohol consumption, and/or drug use Infant’s age: SIDS incidence peaks around 2–4 months of the infant’s age, and subsequently decreases by 1 year. Infant gut flora develops through a period of instability in the early months of infancy and reaches more mature adult-like microbiome by 1 year of age, the time by which SIDS disappears. Another condition, not fully explained, affecting the infant during a typical window period is infant colic, in which aberrant gut flora has been recently shown to play a role, amenable to probiotics. Infantile colic is associated with a greater extent with near-miss SIDS infants than among control infants, thereby hypothesizing that colic might play a role as a protective arousal mechanism in such infants ( infants . From in(10)Gestation at birth: prematurity is associated with a fourfold increased risk of SIDS Small for gestational age (SGA): it has been hypothesized that SGA infants may have a higher incidence of SIDS as a result of fetal hypoxia-induced decrease in brain serotonergic receptors  of SIDS (We have provided a new SIDS hypothesis whereby the right composition of gut flora in the early critical stage of infant development could possibly optimize or modulate serotonin homeostasis in the serotonergic cardiorespiratory/thermoregulatory brain stem nuclei by a direct communication  of SIDS .VP was involved in concept and manuscript preparation. SP was involved in editing of the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Running agility is required for many sports and other physical tasks that demand rapid changes in body direction. Quantifying agility skill remains a challenge because measuring rapid changes of direction and quantifying agility skill from those measurements are difficult to do in ways that replicate real task/game play situations. The objectives of this study were to define and to measure agility performance for a (five-cone) agility drill used within a military obstacle course using data harvested from two foot-mounted inertial measurement units (IMUs). Thirty-two recreational athletes ran an agility drill while wearing two IMUs secured to the tops of their athletic shoes. The recorded acceleration and angular rates yield estimates of the trajectories, velocities and accelerations of both feet as well as an estimate of the horizontal velocity of the body mass center. Four agility performance metrics were proposed and studied including: 1) agility drill time, 2) horizontal body speed, 3) foot trajectory turning radius, and 4) tangential body acceleration. Additionally, the average horizontal ground reaction during each footfall was estimated. We hypothesized that shorter agility drill performance time would be observed with small turning radii and large tangential acceleration ranges and body speeds. Kruskal-Wallis and mean rank post-hoc statistical analyses revealed that shorter agility drill performance times were observed with smaller turning radii and larger tangential acceleration ranges and body speeds, as hypothesized. Moreover, measurements revealed the strategies that distinguish high versus low performers. Relative to low performers, high performers used sharper turns, larger changes in body speed , and shorter duration footfalls that generated larger horizontal ground reactions during the turn phases. Overall, this study advances the use of foot-mounted IMUs to quantify agility performance in contextually-relevant settings . Running agility is required for many sports and other physical tasks that demand rapid changes of direction . Understandably, most studies of agility and cutting maneuvers confine experiments to the laboratory, where standard optical motion capture methods are employed for human motion analysis; see, for example, –5. In laTurning agility can be defined as the ease with which a body changes direction . ChanginWearable IMUs have been used previously to study turning agility in a variety of contexts. Trunk- or pelvis-mounted IMUs have been employed to evaluate running agility in a five-cone drill , turningIn this study, we analyze data from foot-mounted IMUs to (1) leverage opportunities for drift correction during footfalls and (2) evaluate the extent to which meaningful performance outcomes can be identified with only two sensors. We estimate the trajectory, velocity and acceleration of each foot using a Kalman filtering method that identifies and corrects for sensor drift errors. In particular, the filter exploits the instances when a foot is momentarily at rest during each footfall (i.e. zero velocity updates) to correct for velocity drift error, a strategy originally developed for tracking pedestrians indoors  and lateThe objectives of this study were to define and measure agility performance for a military (five-cone) agility drill using data harvested from two foot-mounted IMUs. We hypothesized that shorter agility drill performance times would be observed with small turning radii and large tangential acceleration ranges and body speeds. These hypotheses were tested by comparing trials performed by 32 participants completing an outdoor five-cone agility drill as described next. In addition to the hypotheses tested, we also explored how foot-mounted IMUs could estimate horizontal ground reactions.The University of Michigan Institutional Review Board approved this study. Thirty-two recreational athletes who were free of musculoskeletal injury  age: 20.1 (2.1) years, height: 1.75 (.13) m, mass: 71.3 (13.7) kg) volunteered to participate and provided written informed consent in accordance with the University of Michigan Institutional Review Board. The individual in this manuscript  has giveParticipants wore a pair of wireless IMUs  taped to the top of athletic shoes . The IMUThe IMUs were secured on the shoes by the same experienced researcher and tightly attached to the shoe top (laces) using athletic tape. Participants carried mock-rifles (3.4kg) for the purpose of understanding performance in this military obstacle course, including performance in the agility run .™ cubic spline function , with an example smoothed trajectory shown in Raw data from the 3-axis accelerometer and 3-axis angular rate gyroscope embedded in the IMUs were processed using custom algorithms. Inertial navigation equations were used to compute the attitude angles of the sensor axes relative to a field-fixed frame of reference as described by Savage  and a cu2>0.7).Each foot’s smoothed trajectory was used to automatically detect the turn and straightaway phases of this agility drill. These phases are immediately apparent in Four agility performance metrics are proposed including: 1) agility drill time (defined above), 2) horizontal body speed, 3) turning radius of the foot trajectory, and 4) tangential body acceleration range. The resultant horizontal body speed is approximated as the average horizontal speed of both feet, assuming the body center of mass horizontal speed remains between that of the feet during running  28]. Th. Th28]. Additionally, the average horizontal ground reaction during each footfall was estimated using the linear impulse-momentum relationship  and was normalized by body mass to compare across participants. We approximated the velocity of the performer’s mass center by the average velocity of the performer’s feet. In order to align the velocity vectors from each foot, the horizontal (x-y) trajectories from each foot were rotated (about the z-axis) such that the start and end positions of each foot were aligned with a constant y-value (matching the agility drill course geometry). The average horizontal ground reaction at each foot was further resolved into tangential and normal components relative to the horizontal foot trajectory of each foot . The ground contact time for each footfall during a turn phase was summed to define a “cumulative footfall duration”. An additional turn phase metric, the “force-generation metric” was calculated as the average horizontal ground reaction during the turn phases divided by the cumulative footfall duration. This force-generation metric is therefore large whenever a participant generates a large horizontal ground reaction in a short period of ground contact time during the turn phases.high”, “mid”, and “low” performance based on sorting all trials by agility drill time into three equal-sized groups. Nineteen trials were included per performance group due to multiple trials performed by the majority of subjects. In some cases, trials of the same performer spanned two performance groups . In order to distinguish the techniques that were used by the performance groups, non-parametric rank-based statistical methods were used (as the data did not meet the assumption for a parametric linear model and predictive models were not the outcome of interest). For each dependent variable, a Kruskal-Wallis omnibus test was performed to compare across performance groups as defined by agility drill time. When this test was significant, post-hoc comparisons were performed using Mean Rank tests  [Agility drill performance was divided into groups of “arisons) . This stAs expected, shorter agility drill time was observed with smaller turning radii Figs , Table 1As expected, shorter agility drill times were observed with larger average tangential acceleration ranges and average body speeds. In addition to testing the hypotheses, results also highlight the influence of the estimated horizontal ground reaction on agility drill time. This study elucidates distinct strategies used by high and low performers in this five-cone agility drill, as distinguished by agility drill time. As hypothesized, shorter agility drill performance times were observed with smaller turning radii, larger tangential acceleration ranges, and larger body speeds using Kruskal-Wallis and mean rank post-hoc statistical analyses. The exemplar data illustrated in The trade-off between body speed and curvature observed in this study of running agility is also observed in the turns executed by slalom skiers , the turRapid changes in direction, signaled by short duration turn phases, require the rapid generation of linear and angular impulses from ground reactions. These impulses accelerate the center of mass of the body in a new (desired) direction and also re-orient the body towards that direction ,16,35. CBy exploiting the use of body-worn IMUs, this study exposes agility performance in a natural context , namely within (a portion of) an outdoor obstacle course. While this approach may increase the validity of the findings for field-based athletic and/or soldier performance, the experimental conditions were obviously less controlled than those in laboratory settings. In particular, there was no control of the length or moisture of the grass, the presence or absence of occasional leaves, slight irregularities or slopes in the terrain, all of which may have affected how participants planned and executed their runs . We also introduce a number of performance metrics based on approximating the trajectory, velocity and acceleration of a participant’s mass center as the average of those computed for the left and right feet (thereby ignoring the added components due to body lean). The same approximations underlie our estimates of the horizontal ground reactions. In addition, the trajectories of each foot are themselves estimated results employing inertial navigation algorithms. In particular, they rely on identifying when the foot is momentarily at rest to provide a “zero velocity update” for the subsequent integration time interval. This procedure can be challenged by temporary sensor saturation during footfalls, though that was rare due to the considerable compliance of the grass terrain. This study was executed within the context of an experiment focused on learning how a military obstacle course is performed. Therefore, (1) participants wore helmets and carried mock-rifles and (2) participants performed other obstacle course tasks before and after the agility drill. A within-subject pilot study of participants did not reveal significant differences (1) in agility drill time if the participant carried the rifle or not, (2) nor in agility drill time vs. agility trial order in participants who repeated the agility drill. However, using military accessories or performing other obstacle tasks could have altered performance in ways that were not detected statistically in the current and pilot studies. While the participants were given break time between obstacle course tasks, fatigue could have affected performance differently within-subject or across-subject. Regardless of potential fatigue-effects, this study’s statistical design enabled detection of a wide-variety of performance strategies and outcomes . Finally, the participants of this study were recreational athletes who had different agility training backgrounds and were not trained during the study, which implies that certain cutting maneuvers could have been physiologically unavailable or unknown to certain performers. Within this cohort, an analysis of participant athletic background  yielded no significant differences vs. agility drill time. However, in the future, it would be interesting to learn how amount of prior agility drill practice and specific agility training programs relate to performance.This study leverages the advantages of using two foot-mounted IMUs to study performance on an outdoor (five-cone) agility drill. The acceleration and angular velocity data harvested from the two IMUs were used to estimate foot (and mass center) trajectory, velocity and acceleration as well as horizontal ground reactions during foot-ground contact. These estimates reveal the following major distinctions between high and low-performing participants, with performance distinguished by the time to complete the agility run. Relative to low performance, high performance is characterized by sharper turns, larger changes in body speed , and shorter duration footfalls that also generate larger, horizontal ground reactions during the turn phases. This study may motivate future extensions on running agility that incorporate additional IMUs to expose whole-body movement and body segment control and phasing. For instance, torso-mounted IMUs may reveal that added body lean during the turn phases enables even smaller turn radii for high performers. Furthermore, data from shank- and thigh-mounted IMUs, as in , may revS1 TableData for each agility run trial are included in this table.(XLSX)Click here for additional data file.


Small glomerular IgA deposits have been reported in patients with liver cirrhosis, mainly as an incidental finding in autopsy studies. We recently encountered nine cirrhotic patients who presented with acute proliferative glomerulonephritis with unusually large, exuberant glomerular immune complex deposits, in the absence of systemic lupus erythematosus (SLE) or monoclonal gammopathy-related kidney disease. Deposits were typically IgA dominant/codominant. Our aim was to further elucidate the etiology, diagnostic pitfalls, and clinical outcomes.We present clinical features and kidney biopsy findings of nine cirrhotic patients with an unusual acute immune complex glomerulonephritis. We also identified native kidney biopsies from all patients with liver cirrhosis at our institution over a 13-year period (January 2004 to December 2016) to evaluate presence of glomerular IgA deposits in them (n = 118).Six of nine cirrhotic patients with the large immune deposits had a recent/concurrent acute bacterial infection, prompting a diagnosis of infection-associated glomerulonephritis and treatment with antibiotics. In the remaining three patients, no infection was identified and corticosteroids were initiated. Three of nine patients recovered kidney function (one recovered kidney function after liver transplant); three patients developed chronic kidney disease but remained off dialysis; two patients became dialysis-dependent and one patient developed sepsis and expired shortly after biopsy. Within the total cohort of 118 patients with cirrhosis, 67 others also showed IgA deposits, albeit small; and 42 patients had no IgA deposits.These cases provide support to the theory that liver dysfunction may compromise clearance of circulating immune complexes, enabling deposition in the kidney. At least in a subset of cirrhotic patients, a superimposed bacterial infection may serve as a “second-hit” and lead to acute glomerulonephritis with exuberant immune complex deposits. Therefore, a trial of antibiotics is recommended and caution is advised before immunosuppressive treatment is offered. Unfortunately, most of these patients have advanced liver failure; therefore both diagnosis and management remain a challenge. Immune complex-mediated glomerulonephritis is characterized by deposits of polyclonal immunoglobulin  forming antigen-antibody complexes in the glomeruli with resultant kidney dysfunction . CommonlWhile there are overlapping histologic, immunofluorescence, and ultrastructural features between the different etiologies of immune complex-mediated glomerulonephritis, the type and location of the glomerular immune complex deposits in conjunction with clinical history and laboratory findings usually point to the underlying etiology. For example, both IgA nephropathy and Staphylococcal infection-associated glomerulonephritis (SAGN) typically have IgA and C3 deposits and may have similar histologic findings, thus, can be difficult to distinguish based on biopsy findings alone. However, clinical history of a recent or ongoing systemic infection, recent onset hematuria and proteinuria would favor the latter –5. LupusAlthough infrequent, one can find mild, incidental IgA immune complex deposits in glomeruli that do not directly result in renal dysfunction/acute glomerulonephritis. One of the most common scenarios is mild IgA deposits seen in the setting of liver cirrhosis , 8 presuThe aim of this study is to present the kidney biopsy findings, demographic features, and clinical outcomes of the nine cirrhotic patients with acute kidney injury and unusually large IgA-containing glomerular immune complex deposits. Additionally, we identified and reviewed kidney biopsies from all cirrhotic patients seen at our institution over a 13-year period to further characterize IgA deposits in this group of patients.We describe nine patients with liver cirrhosis who presented with acute kidney injury and an active immune complex-mediated glomerulonephritis with unusually large, exuberant immune complex deposits that typically showed IgA-dominant or codominant staining. Six of these nine patients presented to the Nephrology Division at the Ohio State University Wexner Medical Center (OSUWMC). Three of the nine patients presented at other hospitals, but their kidney biopsies were sent to our Renal Pathology Division at OSUWMC for diagnostic work-up.Additionally, from our Pathology database we identified all native kidney biopsies from patients with cirrhosis over a 13-year period (January 2004 to December 2016). There were a total of 118 kidney biopsies from patients with liver cirrhosis. Besides the nine cases described above, there were 67 biopsies that had IgA-containing immune complex deposits albeit small and of the usual type; and 42 biopsies with no IgA-containing deposits. Demographic features, etiology of cirrhosis, and the extent of the IgA deposits in all these patients, are described.All renal biopsies were processed using standard techniques for light microscopy, direct immunofluorescence, and electron microscopy. The intensity of immunofluorescent staining was scored as negative (0), mild (1+), moderate (2+), and strong (3+). We scored staining as trace if the intensity is between 0 and 1+ and/or if staining was very scant in distribution. The study was approved by the Office of Responsible Research Practice, Ohio State University Wexner Medical Center, IRB 2011H0364 prior to the beginning of the study. Patient consent was waived by the IRB committee. Additional reseach data has been provided in the Supplemental files.Staphylococcus aureus (MRSA) sepsis, patients 2 and 3 recovered partial kidney function after antibiotics, Patient 5 recovered kidney function after a liver transplant, and patients 4 and 6 remained dialysis-dependent. Three of the nine patients had a negative infectious disease work-up  had IgG and C3 codominant staining with mild IgA. Predominance of one light chain was noted in biopsies of patients 2 and 5, but neither was completely negative and also serum and urine protein electrophoresis and immunofixation workup was negative. No monoclonal protein was detected in any of these patients. Electron microscopy confirmed the presence of unusually large glomerular electron dense immune-type deposits that were primarily mesangial and subendothelial in distribution. Additionally large subepithelial immune-type deposits (“humps”) were seen in one biopsy (patient 6). Microtubular or finger-print substructure was not present in the deposits.A number of systemic diseases have been reported to be associated with development of IgA deposits in the glomeruli, also termed as “secondary IgA nephropathy” ,8. TheseSimilar to prior autopsy studies –15, our Additionally, we describe in detail nine patients with liver cirrhosis who in fact had unusually large exuberant, immune complex deposits and presented with acute kidney injury (due to acute immune complex-mediated proliferative glomerulonephritis). The immune complex deposits typically showed strong IgA staining and moderate to strong C3 and IgG staining. In six patients, there was a known recent/concurrent infection. Thus, it is possible that the underlying liver dysfunction in combination with an active bacterial infection resulted in exuberant deposition of immune complexes in the kidney and development of an acute glomerulonephritis. This hypothesis is particularly supported by the fact that two patients Click here for additional data file.S2 Table(XLSX)Click here for additional data file.


To report a case series in which a modified technique was used to remove retained submacular perfluorocarbon liquid (PFCL) secondary to vitreoretinal surgery for rhegmatogenous retinal detachment.Four patients who had undergone pars plana vitrectomy for rhegmatogenous retinal detachment were further treated with surgical intervention because of retained submacular PFCL. With a three-port pars plana approach, after the internal limiting membrane peeling with indocyanine green staining, a 38-gauge flexible cannula was used to aspirate the submacular perfluorocarbon bubble, followed by fluid-air exchange and air injection into vitreous cavity. Submacular perfluorocarbon liquid was removed successfully and visual acuity had an improvement in all cases.The surgical removal of retained submacular PFCL using a 38-gauge flexible cannula combined with internal limiting membrane peeling and intravitreal air tamponade may provide anatomical and visual satisfactory outcomes.The online version of this article (10.1186/s12886-018-0798-y) contains supplementary material, which is available to authorized users. Perfluorocarbon liquid (PFCL) is now in wide and critical use in vitreoretinal surgery. The presence of submacular PFCL is a significant surgery-associated complication and can lead to functional visual loss, central scotoma and irreversible retinal structural damage . Removal3F8) gas tamponade, as well as phacoemulsification with intraocular lens implantation. Three weeks later, when the patient visited our clinic for the first time postoperatively, 2 bubbles of submacular PFCL were detected on optical coherence tomography (OCT) scans There are several issues that deserve further discussions. First, there is no consensus about the optimal timing for submacular PFCL removal. But in general, earlier removal seems to be more appropriate to improve visual functions and to avoid further retinal damages. As we all know, the photoreceptor inner segment/outer segment (IS/OS) junction has been found to be an important prognostic factor for visual acuity. In our current cases, we noticed that the appearance of photoreceptor layers seemed to be defective, thus necessitating earlier surgical interventions. If we don’t consider the time periods when submacular PFCL is detected, and the patient is willing to accept the surgical intervention, the procedure is recommended in 2 weeks after the initial surgery. Based on our results and the limited number of previously published case reports –8, folloIn conclusion, the surgical removal of subretinal PFCL using a 38-gauge flexible cannula combined with internal limiting membrane peeling and intravitreal air tamponade may provide anatomical and visual satisfactory outcomes.


Percutaneous endoscopic gastrostomy (PEG) is an effective and safe mode of enteral nutrition for patients needing chronic enteric nutritional support. Exchanging PEG tubes may result in complications due to inexperience as well as due to lack of protocol.We encountered a 73 year-old female with unnoticed, accidently detached portion of the internal bumper of a PEG tube in the gastric lumen after a challenging gastrostomy tube exchange.This case report discusses the complications associated with gastrostomy tube exchange and proposes a planned protocol for successful gastrostomy tube exchange. Two meten death –5.A 73-year-old female with chronic malnutrition presented with one-day history of small amount of blood ooze from the PEG skin entry site. Physical examination revealed healthy granulation tissue around the PEG tube with minimal ooze. The patient also complained of non-specific pain in the upper abdomen for 1 month, soon after gastrostomy exchange outside her nursing facility. The prior mushroom-retained PEG tube was exchanged for a new balloon-retained gastrostomy tube. Perhaps, the removed PEG tube was not thoroughly evaluated for any missing parts and no follow-up abdominal radiograph was performed as per their protocol. An abdominal radiograph and CT scan of the abdomen and pelvis revealed a round, radiodense disc in the gastric lumen that was not connected to the balloon-retained PEG tube , 2. The PEG tube placement is a well-accepted route of enteral nutrition in chronically malnourished patients with impaired swallowing . The firWe encountered a rare complication of anterograde extraction of PEG tube with accidently detached and retained intra-gastric internal bumper/mushroom. This may be due to excessive pulling force during PEG tube removal, in addition to the loss of pliability of silicone in the internal bumper due to prolonged action of the gastric contents, leading to difficulty in delivering through the skin site opening . Loss ofDifferent methods have been described in the literature for gastrostomy tube exchange; however, there are no consensus guidelines, which results in a wide variation of replacement and removal techniques ,8,9.We rThis article puts an emphasis on a potential, dreaded complication associated with a simple procedure. This case represents a perfect example of how a simple procedure, such as gastrostomy tube exchange, may lead to disasters if not performed strategically. While awaiting consensus guidelines, we recommend that every institution should establish an optimal protocol for gastrostomy tube exchanges to minimize complications.