ImaGiNe Seldinger: first simulator for Seldinger technique and angiography training.

In vascular interventional radiology, procedures generally start with the Seldinger technique to access the vasculature, using a needle through which a guidewire is inserted, followed by navigation of catheters within the vessels. Visual and tactile skills are learnt in a patient apprenticeship which is expensive and risky for patients. We propose a training alternative through a new virtual simulator supporting the Seldinger technique: ImaGiNe (imaging guided interventional needle) Seldinger. It is composed of two workstations: (1) a simulated pulse is palpated, in an immersive environment, to guide needle puncture and (2) two haptic devices provide a novel interface where a needle can direct a guidewire and catheter within the vessel lumen, using virtual fluoroscopy. Different complexities are provided by 28 real patient datasets. The feel of the simulation is enhanced by replicating, with the haptics, real force and flexibility measurements. A preliminary validation study has demonstrated training effectiveness for skills transfer.

Virtual reality, ultrasound-guided liver biopsy simulator: development and performance discrimination.

OBJECTIVES: The aim of this article was to identify and prospectively investigate simulated ultrasound-guided targeted liver biopsy performance metrics as differentiators between levels of expertise in interventional radiology. METHODS: Task analysis produced detailed procedural step documentation allowing identification of critical procedure steps and performance metrics for use in a virtual reality ultrasound-guided targeted liver biopsy procedure. Consultant (n=14; male=11, female=3) and trainee (n=26; male=19, female=7) scores on the performance metrics were compared. Ethical approval was granted by the Liverpool Research Ethics Committee (UK). Independent t-tests and analysis of variance (ANOVA) investigated differences between groups. RESULTS: Independent t-tests revealed significant differences between trainees and consultants on three performance metrics: targeting, p=0.018, t=-2.487 (-2.040 to -0.207); probe usage time, p = 0.040, t=2.132 (11.064 to 427.983); mean needle length in beam, p=0.029, t=-2.272 (-0.028 to -0.002). ANOVA reported significant differences across years of experience (0-1, 1-2, 3+ years) on seven performance metrics: no-go area touched, p=0.012; targeting, p=0.025; length of session, p=0.024; probe usage time, p=0.025; total needle distance moved, p=0.038; number of skin contacts, p<0.001; total time in no-go area, p=0.008. More experienced participants consistently received better performance scores on all 19 performance metrics. CONCLUSION: It is possible to measure and monitor performance using simulation, with performance metrics providing feedback on skill level and differentiating levels of expertise. However, a transfer of training study is required.

Guidelines for reporting experiments involving animals: the ARRIVE guidelines.

British Journal of Pharmacology (BJP) is pleased to publish a new set of guidelines for reporting research involving animals, simultaneously with several other journals; the 'ARRIVE' guidelines (Animals in Research: Reporting In Vivo Experiments). This editorial summarizes the background to the guidelines, gives our view of their significance, considers aspects of specific relevance to pharmacology, re-states BJP's guidelines for authors on animal experiments and indicates our commitment to carrying on discussion of this important topic. We also invite feedback via the British Pharmacological Society website.

Differential activities of the RET tyrosine kinase receptor isoforms during mammalian embryogenesis.

The RET receptor tyrosine kinase has a critical role in kidney organogenesis and the development of the enteric nervous system. Two major isoforms, RET9 and RET51, differ in the amino acid sequence of the C-terminal tail as a result of alternative splicing. To determine the roles of these isoforms in vivo, we used targeted mutagenesis to generate mice that express either RET9 or RET51. Monoisoformic RET9 mice, which lack RET51, are viable and appear normal. In contrast, monoisoformic RET51 animals, which lack RET9, have kidney hypodysplasia and lack enteric ganglia from the colon. To study the differential activities of the two RET isoforms further, we generated transgenic mice expressing ligand-dependent and constitutively active forms of RET9 or RET51 under the control of the Hoxb7 regulatory sequences. Such RET9 transgenes are capable of rescuing the kidney agenesis in RET-deficient mice or causing kidney hypodysplasia in wild-type animals. In contrast, similar RET51 transgenes fail to rescue the kidney agenesis or cause hypodysplasia. Our findings show that RET9 and RET51 have different signaling properties in vivo and define specific temporal and spatial requirements of c-Ret function during renal development and histogenesis of the enteric nervous system.

Functional receptor for GDNF encoded by the c-ret proto-oncogene.

Glial-cell-line-derived neutrophic factor (GDNF) promotes the survival and phenotype of central dopaminergic noradrenergic and motor neurons, as well as various subpopulations of peripheral sensory and sympathetic neurons. GDNF is structurally related to members of the transforming growth factor (TGF)-beta superfamily, several members of which have well-characterized receptor systems; however, GDNF receptors still remain undefined. Here we show that GDNF binds to, and induces tyrosine phosphorylation of, the product of the c-ret proto-oncogene, an orphan receptor tyrosine kinase, in a GDNF-responsive motor-neuron cell line. Ret protein could also bind GDNF and mediate survival and growth responses to GDNF upon transfection into naive fibroblasts. Moreover, high levels of c-ret mRNA expression were found in dopaminergic neurons of the adult substantia nigra, where exogenous GDNF protected Ret-positive neurons from 6-hydroxydopamine-induced cell death. Thus the product of the c-ret proto-oncogene encodes a functional receptor for GDNF that may mediate its neurotrophic effects on motor and dopaminergic neurons.

GDNF signalling through the Ret receptor tyrosine kinase.

Mutational analysis in humans and mice has demonstrated that the Ret, the product of the c-ret proto-oncogene, a member of the receptor tyrosine kinase (RTK) superfamily, is essential for development of the enteric nervous system and kidney. Despite the established role of Ret in mammalian embryogenesis, its cognate ligand(s) is currently unknown. Here we demonstrate, by using a Xenopus embryo bioassay, that glial-cell-line-derived neurotrophic factor (GDNF), a distant member of the transforming growth factor (TGF)-beta superfamily, signals through the Ret RTK. Furthermore, using explant cultures from wild-type and Ret-deficient mouse embryos, we show that normal c-ret function is necessary for GDNF signalling in the peripheral nervous system. Our data strongly suggest that Ret is a functional receptor for GDNF, and that GDNF, in addition to its potential role in the differentiation and survival of central nervous system neurons, has profound effects on kidney organogenesis and the development of the peripheral nervous system.

Isolation of the Thiobacillus ferrooxidans ntrBC genes using a T. ferrooxidans nifH-lacZ fusion.

An agar plating technique was developed in which the activation of expression of a Thiobacillus ferrooxidans nifH-lacZ gene fusion was used to isolate the ntrBC genes from a T. ferrooxidans gene library. An Escherichia coli ntrC mutant containing the nifH-lacZ fusion was transformed and plated on a low-nitrogen medium so that on flooding with ONPG, the production of yellow colonies indicated the presence of the cloned T. ferrooxidans ntrBC genes. A 4.47 kb region from the T. ferrooxidans chromosome was sequenced. Analysis of the sequence revealed that the ntrB and ntrC genes were closely linked to a third ORF of unknown function. Analysis of the 900 bp region upstream of the T. ferrooxidans ntrBC genes and Southern hybridization experiments confirmed that in T. ferrooxidans ATCC 33020, the glnA and ntrBC genes are unlinked. Expression of the T. ferrooxidans nifH-lacZ fusion in E. coli was activated in the presence of the T. ferrooxidans ntrBC genes and regulated by nitrogen.