Real needle for minimal invasive procedures training using motion sensors and optical flow.

Minimally invasive percutaneous insertion procedures are widely used techniques in medicine. Their success is highly dependent on the skills of the practitioner. This paper presents a haptic simulator for training in these procedures, whose key component is a real percutaneous insertion needle with a sensory system incorporated to track its 3D location at every instant. By means of the proposed embedded vision system, the attitude (spatial orientation) and depth of insertion of a real needle are estimated. The proposal is founded on a novel depth estimation procedure based on optical flow techniques, complemented by sensory fusion techniques with the attitude calculated with data from an Inertial Measurement Unit (IMU) sensor. This procedure allows estimating the needle attitude with an accuracy of tenths of a degree and the displacement with an accuracy of millimeters. The computational algorithm runs on an embedded computer with real-time constraints for tracking the movement of a real needle. This haptic needle location data is used to reproduce the movement of a virtual needle within a simulation app. As a fundamental result, an ergonomic and realistic training simulator has been successfully constructed for healthcare professionals to acquire the mental model and motor skills necessary to practice percutaneous procedures successfully.

Software Suite Training Tool for MSK Exploration and Botulinum Toxin Infiltration Based on Ultrasound Imaging for the Spasticity Treatment.

Nowadays, one of the choice techniques for the spasticity treatment is the ultrasound-guided infiltration of Botulinum Toxin, because it is safe and effective. In order to medical professionals can carry out this technique, they need training and education. One of the safest and most time-free ways to facilitate the acquisition of practical medical skills is through simulators. In this paper we present an innovative technological environment, which includes an ultrasound simulator for training in muscle exploration and infiltration. The simulation platform will guide health professionals, with great realism and high degree of interactivity, in the autonomous training of all the tasks involved in the spasticity treatment procedure by infiltration of Botulinum Toxin, without the need for a real patient or costly phantoms.

[Assessment of an educational intervention regarding blood cultures as process indicators in an emergency department in Argentina]. / Evaluación del impacto de una intervención educativa en indicadores de gestión de un servicio médico de urgencias de Argentina.

OBJECTIVE: The aim of this study was to describe 2 process indicators related to taking blood cultures (BC) in an Adult Emergency Department of a tertiary university hospital in Buenos Aires,and to describe the changes after a series of educational activities for health professionals was implemented during May 2016 as regards the appropriate indication of BC and the proper collection technique. MATERIALS AND METHODS: A retrospective cohort study was designed to assess its effectiveness, which consecutively included all patients admitted during 2015-2016. The BC request rate was used as a process indicator, and the percentage of contaminated BCs and the true positives rate were used as quality indicators. Both were measured monthly and prospectively during the period of study. RESULTS: The annual adjusted rate of BC requests was 4.9% (95% CI 4.8-5) in 2015 and 2.9% (95% CI 2.8-2.9) in 2016. The rate of false positive (contaminated) BCs was 4.5% in 2015 and 4.3% after the educational intervention. The true positive BCs were 8.3% in 2015 and 12% post-intervention. CONCLUSIONS: These findings prove how important and effective the educational interventions are.

[Sauvé-Kapandji procedure in distal radioulnar joint disorders]. / Procedimiento de Sauvé-Kapandji en los trastornos de la articulación radiocubital distal.

OBJECTIVE: To evaluate the functional and subjective results of the Sauvé-Kapandji procedure as a treatment for distal radioulnar joint disorders. MATERIAL AND METHOD: A retrospective study was conducted on 27 patients treated using the Sauvé-Kapandji technique from January 2001 to March 2012. The aetiología, age, sex, laterality, articular movement, radiographical signs of joint degeneration, and cubitus varus, were analysed. The Mayo Clinic wrist assessment scale and the DASH questionnaire were used for the postoperative evaluation. The mean follow-up was 24 months (6-48 months). The mean age was 47.2 years, with 66.7% females, and 55% the dominant side. RESULTS: At one year after surgery, 16 cases had mild or no pain (59.2%), 8 cases with moderate (29.6%) and 3 cases with severe pain (11.1%). The pronation-supination went from a pre-operative average of 96.8° to 136.4° postoperative, operatorios, which was a significant statistical difference (Wilcoxon test). The radioulnar ratio went from an pre-operative average of +2.6mm to -0.39 mm postoperative. Full functional recovery was observed in 48%. A grip strength of 50.6%, compared to the contralateral wrist was achieved. CONCLUSIONS: The Sauvé-Kapandji technique could avoid the complications common in other procedures, such as cubital-carpal migration. Our study agrees with that in the literature with good results as regards the range of joint movement, with an acceptable improvement in pain compared to the previous stage, but it also demonstrates the frequent loss of grip strength and instability of the proximal radio-ulnar joint.

[Radiologic study on postnatal ossification of the first metatarsal bone]. / Estudio radiológico sobre la osificación postnatal del primer metatarsiano.

BACKGROUND: Classical descriptions of the ossification of the first metatarsal bone show the existence of a single proximal secondary ossification nucleus, mimicking the typical ossification of a phalanx. However, there are studies that show the presence of a second distal ossification nucleus and discuss its nature: epiphysis or pseudoepiphysis. The objective of the study is to establish the prevalence of such distal nucleus, determine its role in the growth of the radius and its relation with different qualitative variables. MATERIAL AND METHODS: We conducted a retrospective study that included 971 dorsoplantar images from 225 patients. We analyzed the presence of such nucleus, the age of appearance and closure, the relation with different qualitative variables and their contribution to the longitudinal growth of the first metatarsal bone. RESULTS: The distal ossification nucleus appears in 40% of all images and in 81.1% of cases ages 4-7 years. Mean age of appearance is 3.07 years, while physeal closure occurs at a mean of 7.67 years. We found a significantly higher frequency of physeal closure in children, patients with Egyptian type foot, flat foot, and index-plus and Egyptian type foot combinations. The definitive length of the first metatarsal bone is greater in patients with a distal ossification nucleus. CONCLUSIONS: We may state the presence of the distal ossification nucleus of the first metatarsal bone that behaves as a fertile growth cartilage.

WIP is a negative regulator of neuronal maturation and synaptic activity.

Wiskott-Aldrich syndrome protein (WASP) -interacting protein (WIP) is an actin-binding protein involved in the regulation of actin polymerization in cells, such as fibroblasts and lymphocytes. Despite its recognized function in non-neuronal cells, the role of WIP in the central nervous system has not been examined previously. We used WIP-deficient mice to examine WIP function both in vivo and in vitro. We report here that WIP(-)(/-) hippocampal neurons exhibit enlargement of somas as well as overgrowth of neuritic and dendritic branches that are more evident in early developmental stages. Dendritic arborization and synaptogenesis, which includes generation of postsynaptic dendritic spines, are actin-dependent processes that occur in parallel at later stages. WIP deficiency also increases the amplitude and frequency of miniature excitatory postsynaptic currents, suggesting that WIP(-)(/-) neurons have more mature synapses than wild-type neurons. These findings reveal WIP as a previously unreported regulator of neuronal maturation and synaptic activity.

Intracellular machinery for the transport of AMPA receptors.

AMPA-type glutamate receptors are one of the most dynamic components of excitatory synapses. Their regulated addition and removal from synapses leads to long-lasting forms of synaptic plasticity, known as long-term potentiation (LTP) and long-term depression (LTD). In addition, AMPA receptors reach their synaptic targets after a complicated journey involving multiple transport steps through different membrane compartments. This review summarizes our current knowledge of the trafficking pathways of AMPARs and their relation to synaptic function and plasticity.

[Esophageal atresia type I. Is impossible possible?]. / Atresia de esófago tipo I. Es posible lo imposible?

INTRODUCTION: Treatment of esophageal atresia with "long gap" remains difficult and controversial. According to the idea that esophageal anastomosis is imposible in most cases, several esophageal substitution methods have been proposed, as esophagocoloplasty, gastric transposition or reversed gastric tube. Nevertheless reconstruction of native esophagus is accepted as the best option if posible. "Long gap" definition is imprecise, expressed by variability in percent of these cases in total esophageal atresias reported in different series in literature. We report our experience in seven cases type I esophageal atresia with long gap and the different therapeutic options used, with attention to delayed or early esophageal anastomosis feasibility and outcome. MATERIAL AND METHODS: We have treated 121 patients with esophageal atresia from whom we analized 7 cases with pure esophageal atresia with "long gap" (5.8%). Six patients underwent gastrostomy and two gastrostomy and esophagostomy. Five patient underwent primary repair with esophageal anastomosis, delayed between 14 days and 4 months in 4 cases. One patient underwent esophageal anastomosis in the first day without gastrostomy. Retroesternal esophagocoloplasty was performed in 2 patients about their first year of life. Esophagogram was done in first month after surgery and pH monitoring of gastroesophageal reflux. Follow-up ranged from 6 months to 28 years. RESULTS: Esophageal anastomosis was feasible in all 5 patients in whom it was tried. Stricture occurred in two patients, one patient underwent anastomotic resection and new esophageal anastomosis. Esophageal reflux was present in two patients, one of them required funduplication. One patient was dead by complications of cardiac malformation. Remaining patients have normal swallowing and are in normal growth curves. Patients with esophagocoloplasty had not relevant early or late complications. CONCLUSIONS: In most pure esophageal atresia, delayed or even early esophageal anastomosis is feasible, making use of surgical and anesthesic sources that favour it. Esophageal substitution techniques can be reserved if this approach fails.

Atresia de esófago tipo I ¿Es posible lo imposible? / Sigmoid colon vaginoplasty: experience with five cases

Introducción. El tratamiento de la atresia de esófago con gran distancia entre bolsones (long gap) sigue siendo difícil y controvertido. Se han utilizado diversos métodos de sustitución esofágica considerando que en muchos casos la anastomosis esofágica es imposible. Sin embargo se acepta que la conservación del propio esófago es la mejor opción si es posible. La definición de long gap es imprecisa, como lo demuestra el variable porcentaje que representan estos casos en las distintas series de la literatura. Revisamos 7 casos de atresia de esófago tipo I con long gap y las diversas opciones terapéuticas que se utilizaron, analizando la posibilidad y evolución de una anastomosis esofágica diferida o precoz. Material y métodos. Se analizan 7 casos de atresia de esófago tipo I de un total de 121 casos de atresia de esófago (5,8%). En 6 pacientes se realizó gastrostomía y se añadió esofagostomía en 2 de ellos. En cinco pacientes se realizó anastomosis esofágica primaria, diferida en 4 casos entre 14 días y 4 meses de vida. En un paciente se realizó anastomosis esofágica primaria en el primer día de vida, sin gastrostomía. En dos pacientes se realizó esofagocoloplastia al final del primer año de vida. Se realizó tránsito esofágico en el primer mes postoperatorio y control del reflujo gastroesofágico (RGE) con pHmetría. El período de seguimiento oscila entre 6 meses y 28 años. Resultados. La anastomosis esofágica terminoterminal fue quirúrgicamente posible en los 5 pacientes en los que se intentó. En dos pacientes se produjo una estenosis, requiriendo uno de ellos reintervención con nueva anastomosis. Dos pacientes presentaron RGE, realizándose en uno de ellos funduplicatura gastroesofágica. Un paciente falleció a consecuencia de su malformación cardíaca. Los demás pacientes presentan buen desarrollo ponderoestatural con una deglución normal. Los dos pacientes tratados mediante esofagocoloplastia no presentaron complicaciones graves precoces o tardías. Conclusiones. En la mayoría de las atresias de esófago tipo I es factible la anastomosis esofágica terminoterminal, de forma diferida o precoz, utilizando los recursos quirúrgicos y anestésicos que permiten su realización. Las técnicas de sustitución esofágica pueden quedar reservadas en caso de que fracase esta estrategia (AU)

Introduction. Treatment of esophageal atresia with «long gap» remains difficult and controversial. According to the idea that esophageal anastomosis is imposible in most cases, several esophageal substitution methods have been proposed, as esophagocoloplasty, gastric transposition or reversed gastric tube. Nevertheless reconstruction of native esophagus is accepted as the best option if posible. «Long gap» definition is imprecise, expressed by variability in percent of these cases in total esophageal atresias reported in different series in literature. We report our experience in seven cases type I esophageal atresia with long gap and the different therapeutic options used, with attention to delayed or early esophageal anastomosis feasibility and outcome. Material and methods. We have treated 121 patients with esophageal atresia from whom we analized 7 cases with pure esophageal atresia with «long gap» (5.8%). Six patients underwent gastrostomy and two gastrostomy and esophagostomy. Five patient underwent primary repair with esophageal anastomosis, delayed between 14 days and 4 months in 4 cases. One patient underwent esophageal anastomosis in the first day without gastrostomy. Retroesternal esophagocoloplasty was performed in 2 patients about their first year of life. Esophagogram was done in first month after surgery and ph monitoring of gastroesophageal reflux. Follow-up ranged from 6 months to (..) (AU)

Subunit-specific rules governing AMPA receptor trafficking to synapses in hippocampal pyramidal neurons.

AMPA-type glutamate receptors (AMPA-Rs) mediate a majority of excitatory synaptic transmission in the brain. In hippocampus, most AMPA-Rs are hetero-oligomers composed of GluR1/GluR2 or GluR2/GluR3 subunits. Here we show that these AMPA-R forms display different synaptic delivery mechanisms. GluR1/GluR2 receptors are added to synapses during plasticity; this requires interactions between GluR1 and group I PDZ domain proteins. In contrast, GluR2/GluR3 receptors replace existing synaptic receptors continuously; this occurs only at synapses that already have AMPA-Rs and requires interactions by GluR2 with NSF and group II PDZ domain proteins. The combination of regulated addition and continuous replacement of synaptic receptors can stabilize long-term changes in synaptic efficacy and may serve as a general model for how surface receptor number is established and maintained.

The hairpin ribozyme substrate binding-domain: a highly constrained D-shaped conformation.

The two domains of the hairpin ribozyme-substrate complex, usually depicted as straight structural elements, must interact with one another in order to form an active conformation. Little is known about the internal geometry of the individual domains in an active docked complex. Using various crosslinking and structural approaches in conjunction with molecular modeling (constraint-satisfaction program MC-SYM), we have investigated the conformation of the substrate-binding domain in the context of the active docked ribozyme-substrate complex. The model generated by MC-SYM showed that the domain is not straight but adopts a bent conformation (D-shaped) in the docked state of the ribozyme, indicating that the two helices bounding the internal loop are closer than was previously assumed. This arrangement rationalizes the observed ability of hairpin ribozymes with a circularized substrate-binding strand to cleave a circular substrate, and provides essential information concerning the organization of the substrate in the active conformation. The internal geometry of the substrate-binding strand places G8 of the substrate-binding strand near the cleavage site, which has allowed us to predict the crucial role played by this nucleotide in the reaction chemistry.

Postnatal synaptic potentiation: delivery of GluR4-containing AMPA receptors by spontaneous activity.

To examine how functional circuits are established in the brain, we studied excitatory transmission in early postnatal hippocampus. Spontaneous neural activity was sufficient to selectively deliver GluR4-containing AMPA receptors (AMPA-Rs) into synapses. This delivery allowed non-functional connections to transmit at resting potentials and required NMDA receptors (NMDA-Rs) but not CaMKII activation. Subsequently, these delivered receptors were exchanged with non-synaptic GluR2-containing AMPA-Rs in a manner requiring little neuronal activity. The enhanced transmission resulting from this delivery and subsequent exchange was maintained for at least several days and required an interaction between GluR2 and NSF. Thus, this sequence of subunit-specific trafficking events triggered by spontaneous activity in early postnatal development may be crucial for initial establishment of long-lasting functional circuitry.

Driving AMPA receptors into synapses by LTP and CaMKII: requirement for GluR1 and PDZ domain interaction.

To elucidate mechanisms that control and execute activity-dependent synaptic plasticity, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPA-Rs) with an electrophysiological tag were expressed in rat hippocampal neurons. Long-term potentiation (LTP) or increased activity of the calcium/calmodulin-dependent protein kinase II (CaMKII) induced delivery of tagged AMPA-Rs into synapses. This effect was not diminished by mutating the CaMKII phosphorylation site on the GluR1 AMPA-R subunit, but was blocked by mutating a predicted PDZ domain interaction site. These results show that LTP and CaMKII activity drive AMPA-Rs to synapses by a mechanism that requires the association between GluR1 and a PDZ domain protein.

Selective acquisition of AMPA receptors over postnatal development suggests a molecular basis for silent synapses.

Early in postnatal development, glutamatergic synapses transmit primarily through NMDA receptors. As development progresses, synapses acquire AMPA receptor function. The molecular basis of these physiological observations is not known. Here we examined single excitatory synapses with immunogold electron-microscopic analysis of AMPA and NMDA receptors along with electrophysiological measurements. Early in postnatal development, a significant fraction of excitatory synapses had NMDA receptors and lacked AMPA receptors. As development progressed, synapses acquired AMPA receptors with little change in NMDA receptor number. Thus, synapses with NMDA receptors but no AMPA receptors can account for the electrophysiologically observed 'silent synapse'.

[Prenatal diagnosis of ovarian cysts. The ultrasonographic course and therapeutic importance]. / Diagnóstico prenatal del quiste de ovario. Evolución ecográfica y actitud terapéutica.

Before of the implantation of ultrasound there were few cases of ovarian cysts reported in literature because only the very large ones or those which result in mechanical complications produce symptoms. The authors report 17 cases of neonatal ovarian cysts diagnosed by prenatal ultrasound. All of the infants were asymptomatic after birth despite their size or being twisted. The diameter of the cysts varied from 2.5 to 10 cm. Five neonates were treated conservatively and the cysts resolved spontaneously. 12 infants underwent surgery following postnatal confirmation, 9 of these patients had complex ovarian cysts and at laparotomy all of them had torsion of the ovary, three of them were autoamputated, and 3 uncomplicated cysts because their large size or their association to a nephroblastoma. Simple cysts of the ovary tend to resolve spontaneously and therefore, must be treated conservatively. Complex cysts or simple ones larger than 4 cm that do not disappear should undergo surgical removal.

Structural basis for heterogeneous kinetics: reengineering the hairpin ribozyme.

The RNA cleavage reaction catalyzed by the hairpin ribozyme shows biphasic kinetics, and chase experiments show that the slow phase of the reaction results from reversible substrate binding to an inactive conformational isomer. To investigate the structural basis for the heterogeneous kinetics, we have developed an enzymatic RNA modification method that selectively traps substrate bound to the inactive conformer and allows the two forms of the ribozyme-substrate complex to be separated and analyzed by using both physical and kinetic strategies. The inactive form of the complex was trapped by the addition of T4 RNA ligase to a cleavage reaction, resulting in covalent linkage of the 5' end of the substrate to the 3' end of the ribozyme and in selective and quantitative ablation of the slow kinetic phase of the reaction. This result indicates that the inactive form of the ribozyme-substrate complex can adopt a conformation in which helices 2 and 3 are coaxially stacked, whereas the active form does not have access to this conformation, because of a sharp bend at the helical junction that presumably is stabilized by inter-domain tertiary contacts required for catalytic activity. These results were used to improve the activity of the hairpin ribozyme by designing new interfaces between the two domains, one containing a non-nucleotidic orthobenzene linkage and the other replacing the two-way junction with a three-way junction. Each of these modified ribozymes preferentially adopts the active conformation and displays improved catalytic efficiency.

Kinetic mechanism of the hairpin ribozyme. Identification and characterization of two nonexchangeable conformations.

To investigate the relationship between RNA folding and ribozyme catalysis, we have carried out a detailed kinetic analysis of four structural derivatives of the hairpin ribozyme. Optimal and suboptimal (wild-type) substrate sequences were studied in conjunction with stabilization of helix 4, which supports formation of the catalytic core. Pre-steady-state and steady-state kinetic studies strongly support a model in which each of the ribozyme variants partitions between two major conformations leading to active and inactive ribozyme. substrate complexes. Reaction rates for cleavage, ligation, and substrate binding to both ribozyme conformations were determined. Ligation rates (3 min-1) were typically 15-fold greater than cleavage rates (0.2 min-1), demonstrating that the hairpin ribozyme is an efficient RNA ligase. On the other hand, substrate binding is very rapid (kon = 4 x 10(8) M-1 min-1), and the ribozyme. substrate complex is very stable (KD < 25 pM; koff < 0.01 min-1). Stabilization of helix 4 increases the proportion of RNA molecules folded into the active conformation, and enhances substrate association and ligation rates. These effects can be explained by stabilization of the catalytic core of the ribozyme. Rigorous consideration of conformational isomers and their intrinsic kinetic properties was necessary for development of a kinetic scheme for the ribozyme-catalyzed reaction.

In vitro evolution of terminal protein-containing genomes.

A new self-sustained terminal protein-primed DNA amplification system has been used to describe in vitro evolutionary changes affecting maintenance of the genome size of bacteriophage phi29. These changes involve generation and efficient amplification of short palindromic molecules containing an inverted duplication of one of the original DNA ends. A template-switching mechanism is proposed to account for the appearance of these molecules. After their formation, they would replicate by means of hairpin intermediates. Relevant kinetic information about this DNA replication system has been obtained from the competition between the input full-length phi29 DNA and its derived truncated versions. The physiological relevance of these molecules and the mechanisms to control their formation are discussed.

A novel kinetic analysis to calculate nucleotide affinity of proofreading DNA polymerases. Application to phi 29 DNA polymerase fidelity mutants.

Amino acids Tyr254 and Tyr390 of phi 29 DNA polymerase belong to one of the most conserved regions in eukaryotic-type DNA polymerases. In this paper we report a mutational study of these two residues to address their role in nucleotide selection. This study was carried out by means of a new kinetic analysis that takes advantage of the competition between DNA polymerization and 3'-->5' exonuclease activity to measure the Km values for correct and incorrect nucleotides in steady-state conditions. This method is valid for any 3'-->5' exonuclease-containing DNA polymerase, without any restriction concerning catalytic rates of nucleotide incorporation. The results showed that the discrimination factor achieved by phi 29 DNA polymerase in the nucleotide binding step of DNA polymerization is 2.4 x 10(3), that is, a wrong nucleotide is bound with a 2.4 x 10(3)-fold lower affinity than the correct one. Mutants Y254F, Y390F, and Y390S showed discrimination values of 7.0 x 10(2), > 1.9 x 10(3), and 2.9 x 10(2), respectively. The reduced accuracy of nucleotide binding produced by mutations Y254F and Y390S lead us to propose that phi 29 DNA polymerase residues Tyr254 and Tyr390, highly conserved in eukaryotic-type DNA polymerases, are involved in nucleotide binding selection, thus playing a crucial role in the fidelity of DNA replication. Comparison of the discrimination factors of mutants Y390S and Y390F strongly suggests that the phenyl ring of Tyr390 is directly involved in checking base-pairing correctness of the incoming nucleotide.