ElePhant: an anatomic-electronic simulation system for the evaluation of computer assisted interventions and surgical education]

BACKGROUND: Suitable simulation systems providing realistic conditions are required for preclinical evaluation of computer assisted interventions and surgical training. Techniques are necessary for an objective detection of injuries to the structures at risk. The aim of this study was the technical realization of a simulation system for the ENT intervention, mastoidectomy.MATERIALS AND METHODS: The basis of the simulation system was a CT scan of a cadaver skull. Using 3D printing, an anatomical phantom with realistic bone-like properties was created. Electronic detection systems were integrated into the structures at risk. A study with 16 ENT surgeons was conducted to prove the system's suitability for surgical training.RESULTS: The creation of simulation systems for the objective evaluation of surgical intervention qualities is feasible. A modular structure enables economic and simple replacement of the simulation area. The modules are cost effective and reproducible with high accuracy. The present study shows that the simulation system can be applied in surgical education and evaluation as an alternative to cadavers.CONCLUSION: Objective evaluation of injured structures at risk can be realized in real time. The simulation system permits preclinical evaluation studies of computer assisted instruments and surgical education. Reproducibility of the results makes multi-center studies possible.     

Application of multiplex-ready PCR for fluorescence-based SSR genotyping in barley and wheat

Microsatellites (SSRs) are widely used in cereal research, and their use in marker assisted breeding has increased the speed and efficiency of germplasm improvement. Central to the application of SSRs for many purposes are methodologies enabling the low-cost acquisition of large quantities of genetic information for gene and genotype identification. In this study, multiplex-ready PCR was evaluated in barley and bread wheat as an approach for rapid and more automated SSR genotyping on a fluorescence-based DNA fragment analyzer. Multiplex-ready PCR is a method that allows SSR genotyping to be performed using a standardized protocol. The method enables flexible fluorescence labeling of SSRs, generates a relatively constant amount of PCR product for each marker, and has a high amenability to multiplex PCR (the simultaneous amplification of several SSRs in the same reaction). A high (92%) compatibility of published SSRs with multiplex-ready PCR is demonstrated, and the usefulness of the method for large scale genotyping is shown by its application for whole genome marker assisted breeding in barley. A database of more than 2,800 barley and wheat SSRs, and a suite of bio-informatic tools were developed to support the deployment of multiplex-ready PCR for various genetic applications, and are accessible at . Multiplex-ready PCR is broadly applicable to cereal genomics research and marker assisted breeding, and should be transferable to similar analyses of any animal or plant species.     

Robust Brain-Machine Interface Design Using Optimal Feedback Control Modeling and Adaptive Point Process Filtering

Much progress has been made in brain-machine interfaces (BMI) using decoders such as Kalman filters and finding their parameters with closed-loop decoder adaptation (CLDA). However, current decoders do not model the spikes directly, and hence may limit the processing time-scale of BMI control and adaptation. Moreover, while specialized CLDA techniques for intention estimation and assisted training exist, a unified and systematic CLDA framework that generalizes across different setups is lacking. Here we develop a novel closed-loop BMI training architecture that allows for processing, control, and adaptation using spike events, enables robust control and extends to various tasks. Moreover, we develop a unified control-theoretic CLDA framework within which intention estimation, assisted training, and adaptation are performed. The architecture incorporates an infinite-horizon optimal feedback-control (OFC) model of the brain’s behavior in closed-loop BMI control, and a point process model of spikes. The OFC model infers the user’s motor intention during CLDA—a process termed intention estimation. OFC is also used to design an autonomous and dynamic assisted training technique. The point process model allows for neural processing, control and decoder adaptation with every spike event and at a faster time-scale than current decoders; it also enables dynamic spike-event-based parameter adaptation unlike current CLDA methods that use batch-based adaptation on much slower adaptation time-scales. We conducted closed-loop experiments in a non-human primate over tens of days to dissociate the effects of these novel CLDA components. The OFC intention estimation improved BMI performance compared with current intention estimation techniques. OFC assisted training allowed the subject to consistently achieve proficient control. Spike-event-based adaptation resulted in faster and more consistent performance convergence compared with batch-based methods, and was robust to parameter initialization. Finally, the architecture extended control to tasks beyond those used for CLDA training. These results have significant implications towards the development of clinically-viable neuroprosthetics.     

Structural basis for recruitment of the ATPase activator Aha1 to the Hsp90 chaperone machinery

Hsp90 is a molecular chaperone essential for the activation and assembly of many key eukaryotic signalling and regulatory proteins. Hsp90 is assisted and regulated by co-chaperones that participate in an ordered series of dynamic multiprotein complexes, linked to Hsp90s conformationally coupled ATPase cycle. The co-chaperones Aha1 and Hch1 bind to Hsp90 and stimulate its ATPase activity. Biochemical analysis shows that this activity is dependent on the N-terminal domain of Aha1, which interacts with the central segment of Hsp90. The structural basis for this interaction is revealed by the crystal structure of the N-terminal domain (1-153) of Aha1 (equivalent to the whole of Hch1) in complex with the middle segment of Hsp90 (273-530). Structural analysis and mutagenesis show that binding of N-Aha1 promotes a conformational switch in the middle-segment catalytic loop (370-390) of Hsp90 that releases the catalytic Arg 380 and enables its interaction with ATP in the N-terminal nucleotide-binding domain of the chaperone.     

Geriatría transversal. Un reto asistencial para el siglo xxi

Increasing numbers of older persons are being treated by specialties other than Geriatric Medicine. Specialists turn to Geriatric Teams when they need to accurately stratify their patients’ risk and prognosis, predict the potential impact of their, often, invasive interventions, optimise their clinical status, and contribute to discharge planning. Oncology and Haematology, Cardiology, General Surgery, and other surgical departments are examples where such collaborative working is already established, to a varying extent. The use of the term “Cross-speciality Geriatrics” is suggested when geriatric care is provided in clinical areas traditionally outside the reach of Geriatric Teams. The core principles of Geriatric Medicine (comprehensive geriatric assessment, patient-centred multidisciplinary targeted interventions, and input at point-of-care) are adapted to the specifics of each specialty and applied to frail older patients in order to deliver a holistic assessment/treatment, better patient/carer experience, and improved clinical outcomes. Using Comprehensive Geriatric Assessment methodology and Frailty scoring in such patients provides invaluable prognostic information, helps in decision making, and enables personalised treatment strategies. There is evidence that such an approach improves the efficiency of health care systems and patient outcomes. This article includes a review of these concepts, describes existing models of care, presents the most commonly used clinical tools, and offers examples of excellence in this new era of geriatric care. In an ever ageing population it is likely that teams will be asked to provide Cross-specialty Geriatrics across different Health Care systems. The fundamentals for its implementation are in place, but further evidence is required to guide future development and consolidation, making it one of the most important challenges for Geriatrics in the coming years.     

Aptamers come of age - at last

Nucleic-acid aptamers have the molecular recognition properties of antibodies, and can be isolated robotically for high-throughput applications in diagnostics, research and therapeutics. Unlike antibodies, however, they can be chemically derivatized easily to extend their lifetimes in biological fluids and their bioavailability in animals. The first aptamer-based clinical drugs have recently entered service. Meanwhile, active research programmes have identified a wide range of anti-viral aptamers that could form the basis for future therapeutics.     

Structural basis for recruitment of the ATPase activator Aha1 to the Hsp90 chaperone machinery

Hsp90 is a molecular chaperone essential for the activation and assembly of many key eukaryotic signalling and regulatory proteins. Hsp90 is assisted and regulated by co-chaperones that participate in an ordered series of dynamic multiprotein complexes, linked to Hsp90 conformationally coupled ATPase cycle. The co-chaperones Aha1 and Hch1 bind to Hsp90 and stimulate its ATPase activity. Biochemical analysis shows that this activity is dependent on the N-terminal domain of Aha1, which interacts with the central segment of Hsp90. The structural basis for this interaction is revealed by the crystal structure of the N-terminal domain (1-153) of Aha1 (equivalent to the whole of Hch1) in complex with the middle segment of Hsp90 (273-530). Structural analysis and mutagenesis show that binding of N-Aha1 promotes a conformational switch in the middle-segment catalytic loop (370-390) of Hsp90 that releases the catalytic Arg 380 and enables its interaction with ATP in the N-terminal nucleotide-binding domain of the chaperone.     

An integrative computational model for intestinal tissue renewal

Objectives:  The luminal surface of the gut is lined with a monolayer of epithelial cells that acts as a nutrient absorptive engine and protective barrier. To maintain its integrity and functionality, the epithelium is renewed every few days. Theoretical models are powerful tools that can be used to test hypotheses concerning the regulation of this renewal process, to investigate how its dysfunction can lead to loss of homeostasis and neoplasia, and to identify potential therapeutic interventions. Here we propose a new multiscale model for crypt dynamics that links phenomena occurring at the subcellular, cellular and tissue levels of organisation.
Methods:  At the subcellular level, deterministic models characterise molecular networks, such as cell-cycle control and Wnt signalling. The output of these models determines the behaviour of each epithelial cell in response to intra-, inter- and extracellular cues. The modular nature of the model enables us to easily modify individual assumptions and analyse their effects on the system as a whole.
Results:  We perform virtual microdissection and labelling-index experiments, evaluate the impact of various model extensions, obtain new insight into clonal expansion in the crypt, and compare our predictions with recent mitochondrial DNA mutation data.
Conclusions:  We demonstrate that relaxing the assumption that stem-cell positions are fixed enables clonal expansion and niche succession to occur. We also predict that the presence of extracellular factors near the base of the crypt alone suffices to explain the observed spatial variation in nuclear beta-catenin levels along the crypt axis.     

Why not Commercial Assistance for Suicide? On the Question of Argumentative Coherence of Endorsing Assisted Suicide

Most people who endorse physician‐assisted suicide are against commercially assisted suicide – a suicide assisted by professional non‐medical providers against payment. The article questions if this position – endorsement of physician‐assisted suicide on the one hand and rejection of commercially assisted suicide on the other hand – is a coherent ethical position. To this end the article first discusses some obvious advantages of commercially assisted suicide and then scrutinizes six types of argument about whether they can justify the rejection of commercially assisted suicide while simultaneously endorsing physician‐assisted suicide. The conclusion is that they cannot provide this justification and that the mentioned position is not coherent. People who endorse physician‐assisted suicide have to endorse commercially assisted suicide as well, or they have to revise their endorsement of physician‐assisted suicide.     

Concerted release of substrate domains from GroEL by ATP is demonstrated with FRET

The chaperonin GroEL assists protein folding by undergoing ATP-induced conformational changes that are concerted within each of its two back-to-back stacked rings. Here we examined whether concerted allosteric switching gives rise to all-or-none release and folding of domains in a chimeric fluorescent protein substrate, CyPet-YPet. Using this substrate, it was possible to determine the folding yield of each domain from its intrinsic fluorescence and that of the entire chimera by measuring Förster resonance energy transfer between the two domains. Hence, it was possible to determine whether release of one domain is accompanied by release of the other domain (concerted mechanism), or whether their release is not coupled. Our results show that the chimera's release tends to be concerted when folding is assisted by a wild-type GroEL variant, but not when assisted by the F44W/D155A mutant that undergoes a sequential allosteric switch. A connection between the allosteric mechanism of this molecular machine and its biological function in assisting folding is thus established.     

TREATMENT NEEDS IN HIV PREVENTION TRIALS: USING BENEFICENCE TO CLARIFY SPONSOR‐INVESTIGATOR RESPONSIBILITIES

Some participants will get HIV‐infected in HIV prevention trials, despite risk reduction measures. The subsequent treatment responsibilities of sponsor‐investigators have been widely debated, especially where access to antiretroviral therapy (ART) is not available. In this paper, we explore two accounts of beneficence to establish whether they can shed light on sponsor‐investigator responsibilities. We find the notion of general beneficence helpful insofar as it clarifies that some beneficent actions will be obligatory where they can be dispensed without scuppering the trial. We find the notion of specific beneficence helpful insofar as it directs investigators to attend to the needs of trial participants; however the range of interventions that could be provided remains unhelpfully broad. We then examine accounts of the investigator‐participant relationship to narrow the range of interventions that investigators should provide, concluding that health‐care, and HIV infection, are appropriate foci. We conclude that when investigators are able to meet the ART needs of their participants (e.g. referral, assisted referral or direct provision) without sacrificing trial quality, they must do so. However, there is little of this explicit direction to be found in the account of specific beneficence itself, but rather it is found in accounts of the relationship that are compatible with beneficence.     

When should a mare go for assisted reproduction?

The use of assisted reproductive techniques (ART) has helped owners to produce offspring from valuable mares that were considered infertile using standard breeding techniques. Before referring a mare for an ART, the practitioner should be able to identify the underlying cause of subfertility of the mare. The objective of this review is to provide information regarding embryo transfer, oocyte transfer and intracytoplasmic sperm injection, the three most common ART used in equine practice. Knowing the complexity as well as the risks of these techniques, enables practitioners to refer a subfertile mare to the least complex and most appropriate and successful ART that can overcome specific causes of infertility.     

Robotic simulation of identical athletic-task kinematics on cadaveric limbs exhibits a lack of differences in knee mechanics between contralateral pairs

Limb asymmetry is a known factor for increased ACL injury risk. These asymmetries are normally observed during in vivo testing. Prior studies have developed in vitro testing methodologies driven by in vivo kinematics to investigate knee mechanics relative to ACL injury. The objective of this study was to determine if mechanical side-to-side asymmetries persist in contralateral pairs during in vitro simulation testing. In vivo kinematics were recorded for male and female drop vertical jump and sidestep cutting tasks. The recorded kinematics were used to robotically simulate the motions on 7 contralateral pairs of cadaveric lower extremities specimens. ACL and MCL force, torque, and strains were recorded and analyzed for differences between contralateral pairs. There was a general lack of mechanical differences between limb sides. Adduction peak torque for the male sidestep cut movement was significantly different between limb sides (p=0.04). However, this is consistent with ACL injury mechanics in that movement in the frontal plane (abduction/adduction) increases injury risk and it is possible loading differences in this plane may have resulted from tolerances within the setup process. The findings of this study indicate that contralateral knee joints were representative of each other during biomechanical in vitro tests. In future cadaveric robotic simulations, contralateral limbs can be used interchangeably. In addition, direct comparisons of the structural behaviors of isolated conditions for contralateral knee joints can be performed.     

What Interrupts Suicide Attempts in Men: A Qualitative Study

Despite higher rates of suicide in men, there is a dearth of research examining the perspectives and experiences of males at risk of suicide, particularly in terms of understanding how interventions can be tailored to men’s specific needs. The current study aimed to examine factors assisting, complicating or inhibiting interventions for men at risk, as well as outlining the roles of family, friends and others in male suicide prevention. Thirty-five male suicide survivors completed one-to-one interviews, and forty-seven family and friends of male suicide survivors participated in eight focus groups. Thematic analysis revealed five major themes: (1) development of suicidal behaviours tends to follow a common path associated with specific types of risk factors (disrupted mood, unhelpful stoic beliefs and values, avoidant coping strategies, stressors), (2) men at risk of suicide tend to systematically misinterpret changes in their behaviour and thinking, (3) understanding mood and behavioural changes in men enables identification of opportunities to interrupt suicide progression, (4) distraction, provision of practical and emotional supports, along with professional intervention may effectively interrupt acute risk of harm, and (5) suicidal ideation may be reduced through provision of practical help to manage crises, and helping men to focus on obligations and their role within families. Findings suggest that interventions for men at risk of suicidal behaviours need to be tailored to specific risk indicators, developmental factors, care needs and individuals’ preferences. To our knowledge this is the first qualitative study to explore the experiences of both suicidal men and their family/friends after a suicide attempt, with the view to improve understanding of the processes which are effective in interrupting suicide and better inform interventions for men at risk.     

In vitro fertilization by intracytoplasmic sperm injection

Intracytoplasmic sperm injection (ICSI) is the latest, and by far the most efficient, variant of micromanipulation-assisted fertilization, whereby a single spermatozoon is selected, aspirated into a microinjection needle and injected to the oocyte cytoplasm. The development of this technique is mainly linked to application in human assisted reproduction for which it enables fertilization with defective spermatozoa that would not otherwise be able to penetrate an oocyte by their proper means. Because ICSI by-passes many steps of the natural fertilization process, it offers an extremely interesting model for the study of basic mechanisms underlying fertilization. This is particularly true for oocyte activation, whose mechanism needs to be revisited in light of the current ICSI research. The massive application of ICSI in human infertility treatment also represents a huge laboratory in which the impact of different genetic and epigenetic anomalies of the male gamete on fertilization and embryonic development can be studied. BioEssays 21:791–801, 1999. © 1999 John Wiley & Sons, Inc.     

Seamless site-directed mutagenesis of the <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> genome using CRISPR-Cas9

CRISPR assisted homology directed repair enables the introduction of virtually any modification to the Saccharomyces cerevisiae genome. Of obvious interest is the marker-free and seamless introduction of point mutations. To fulfill this promise, a strategy that effects single nucleotide changes while preventing repeated recognition and cutting by the gRNA/Cas9 complex is needed. We demonstrate a two-step method to introduce point mutations at 17 positions in the S. cerevisiae genome. We show the general applicability of the method, enabling the seamless introduction of single nucleotide changes at any location, including essential genes and non-coding regions. We also show a quantifiable phenotype for a point mutation introduced in gene GSH1. The ease and wide applicability of this general method, combined with the demonstration of its feasibility will enable genome editing at an unprecedented level of detail in yeast and other organisms.     

Semi-quantitative expression and knockdown of a target gene in single-cell mouse embryonic stem cells by high performance microinjection

Interactions of multiple genes and associated factors are involved in the differentiation and de-differentiation of embryonic stem (ES) cells. Quantitative analysis of these genes and factors is essential for the elucidation of their mechanism. To meet this requirement, we have investigated various experimental conditions for high performance microinjection into mouse ES cells. A speedy and rhythmic operation was found to be important and was accomplished robotically by using a single-cell manipulation technique and XY-address registrable culture dishes. Among many experimental parameters, the tip size of an injection capillary, the pressure condition, and the DNA concentration in the injection capillary were of critical significance. Their optimum values were 0.5–0.8 μm, 0.7 kgf/cm² for 30 ms, and 1–100 ng/μl, respectively. Under these conditions, semi-quantitative control of the EGFP gene expression in mouse ES cells and its knockdown was successfully demonstrated.