Guidance Tube Research Articles

Design and application of alaryngeal mask and monitoring device facilitating withdrawal of endotracheal tube

Percutaneous dilatational tracheostomy (PDT) is a surgical method for quickly establishing an artificial airway, which has been favored by clinicians because of its simple operation, small trauma and bedside operation. However, for patients with tracheal intubation in intensive care unit (ICU), the tip and balloon of the existing endotracheal tube will not only hinder percutaneous puncture, but also hinder insertion of guidewire and tracheotomy tube, and consequently affect the process of PDT. On the contrary, blind withdrawal of the existing endotracheal tube may cause the tracheal tube tipleave the glottis, leading to an emergency airway situation that endangers the patient's life. Therefore, the medical staff from intensive care medicine department of the First People's Hospital of Chenzhou designed a laryngeal mask and its monitoring device, which is convenient for withdrawal of endotracheal tube, and obtained the national utility model patent of China (patent number: ZL 2020 2 2795887.1). The device is composed of a laryngeal mask and a monitoring device. The laryngeal mask mainly includes a laryngeal mask body, a vent tube, a guidance tube and other components. The laryngeal mask body is mainly used to seal the throat and provide the air supply channel for the patient together with the ventilation tube. The main function of the guidance tube is to accommodate the tracheal tube and facilitate the withdrawal of the inserted tracheal tube. During percutaneous dilatation tracheotomy, this device can monitor the withdrawal of tracheal catheter in real time, and immediately ensure the airway patency of patients without re-intubation when the cuff of tracheal catheter exits the glottis. The utility model has the advantages of real-time monitoring, simple operation, safety and convenience, and is worthy of transformation and promotion.

Experimental investigation on self-induced jet impingement boiling using R1336mzz(Z)

Pool boiling performance enhancement has attracted considerable interest on high power electronic cooling. In this paper, we introduce a self-induced jet impingement device for practical boiling enhancement, achieved by integrating the guidance tube with an orifice plate. With R1336mzz(Z) as the working fluid, we conduct visualization and parametric investigations on the pool boiling performance, considering the varying characteristics of this device. Visualization snapshots confirm the liquid-vapor separation and indicate that the two-phase flow pattern in the guidance tube eventually stabilizes as a churn-annular flow. Our findings suggest that self-induced liquid jet impingement has a minimal effect on the nucleate boiling heat transfer coefficient (hNB) under a certain heat flux, around 75 % CHF of the standard pool boiling, as the single-phase heat transfer is weakened due to the low thermal conductivity of R1336mzz(Z). As the heat flux intensifies, we observe substantial enhancements in both the Critical Heat Flux (CHF) and the Maximum Nucleate Boiling Heat transfer coefficient (hMNB) resulted from the delayed onset of boiling crisis, owing to the additional liquid supply and the promotion on vapor exhausting. The parametric studies reveal that the flow rate of the liquid jet, amplified by either extending the length or the inner diameter of the guidance tube, or by increasing the number of jet holes, positively impacts the boiling performance. However, these improvements show diminishing returns. Our study shows enhancements in CHF and hMNB of up to 69.5 % and 36.7 %, respectively, compared to the standard pool boiling.

Tissue engineered axon-based "living scaffolds" promote survival of spinal cord motor neurons following peripheral nerve repair.

Peripheral nerve injury (PNI) impacts millions annually, often leaving debilitated patients with minimal repair options to improve functional recovery. Our group has previously developed tissue engineered nerve grafts (TENGs) featuring long, aligned axonal tracts from dorsal root ganglia (DRG) neurons that are fabricated in custom bioreactors using the process of axon "stretch-growth." We have shown that TENGs effectively serve as "living scaffolds" to promote regeneration across segmental nerve defects by exploiting the newfound mechanism of axon-facilitated axon regeneration, or "AFAR," by simultaneously providing haptic and neurotrophic support. To extend this work, the current study investigated the efficacy of living versus nonliving regenerative scaffolds in preserving host sensory and motor neuronal health following nerve repair. Rats were assigned across five groups: naïve, or repair using autograft, nerve guidance tube (NGT) with collagen, NGT + non-aligned DRG populations in collagen, or TENGs. We found that TENG repairs yielded equivalent regenerative capacity as autograft repairs based on preserved health of host spinal cord motor neurons and acute axonal regeneration, whereas NGT repairs or DRG neurons within an NGT exhibited reduced motor neuron preservation and diminished regenerative capacity. These acute regenerative benefits ultimately resulted in enhanced levels of functional recovery in animals receiving TENGs, at levels matching those attained by autografts. Our findings indicate that TENGs may preserve host spinal cord motor neuron health and regenerative capacity without sacrificing an otherwise uninjured nerve (as in the case of the autograft) and therefore represent a promising alternative strategy for neurosurgical repair following PNI.

Pool boiling enhancement through a guidance structure mounted above heating surface

A guidance structure mounted above a heating surface is proposed to enhance pool boiling heat transfer in this paper. The basic idea is to form separated vapor-liquid pathways with a rising slug flow and a replenishing liquid impingement vertically onto the heating surface through an integrated bubble pump. Visualization and heat transfer experiments of pool boiling of water on a copper surface are conducted under saturation temperatures of 50 °C, 70 °C and 100 °C for 3 test sections without a guidance tube, with a straight guidance tube and with a trumpet guidance tube. It is found with increasing heat flux, the unidirectional fluid circulation becomes steadier, and the bubble pumping velocity and liquid impingement velocity increase. The trumpet guidance tube is more favorable to achieve unidirectional fluid circulation than the straight guidance tube due to the bubble collection effect of the trumpet, which has larger liquid impingement velocity due to its narrower annulus for the returning liquid. Both guidance tubes can enhance the critical heat flux (CHF) and the heat transfer coefficient (HTC) drastically, especially at lower saturation temperatures where bubble pump is more efficient because of lower vapor density. At a saturation temperature of 50 °C, the CHF and the maximum HTC of trumpet guidance tube are 109.0 W/cm2 and 38.8 kW/m2 °C, respectively, which are 4.1 and 2.8 times of the test section without a guidance tube. In general, the trumpet guidance tube has better performance than the straight guidance tube with respect to CHF and the maximum HTC. However, at a saturation temperature of 100 °C, HTC of the trumpet guidance tube at relatively low heat fluxes is lower because of the suppression of nucleate boiling by the larger liquid impingement velocity.

Cumulative Evaluation Data: Simulation Based Learning Courses for Pediatric R1 Residents

Objectives: To utilize cumulative evaluation data of the Intensive pediatric simulation-based learning course on knowledge and practical skills for pediatric R1 residents at Saudi Commission for Health Speciality (SCFHS) in order to measure its efficacy and areas for improvement. Methods: This evaluation design is a retrospective cohort study that compares pre- post- and retention test 6 months later (knowledge and skills) of an intensive pediatric R1 simulation course. The five-day bundle courses has been conducted once per month at CRESENT and is comprised of airway management with crew resource management, central line insertion under ultrasound guidance, thoracocentesis and chest tube insertion, chest X-ray interpretation and lung ultrasound, lumbar puncture and bone marrow aspiration and biopsy and cardiac simulation course. Our evaluation data includes all pediatric R1 residents who attended the course between September 2017 and May 2018. Results: A total number of 43 trainees, 23 residents (43.5%) are males and 20 (46.5%) are females.18 (41.9%) are KfMC residents and 25 (58.1%) non-KFMC residents (Table 1). Overall, there is statistically significant improvement between the pretest and post-test knowledge and practical skills scores for all the courses. Airway management simulation course, central line catheter insertion under ultrasound guidance course and lumbar puncture course a comparative analysis for knowledge and practical skills assessment of pre-test and post-test mean scores showed significant statistical improvement with P-value <0.001. Similarly, a comparative analysis for knowledge assessment of pre-test and post-test mean scores for all the five courses including pediatric cardiac simulation course and pediatric chest X-ray interpretation course showed significant statistical improvement with P-value <0.001.Retention test were limited to 4 candidates did retention practical skills test and showed 100% improvement in their scores while 9 candidates did retention knowledge test for airway management course, central line insertion under ultrasound guidance course and lumbar puncture course which showed 50% less than post test but more than pretest score, 30% had equivocal as post test and 20% more than post test score. Majority enjoyed training in simulation environment Discussion: This study shows the importance and effectiveness of the pediatric simulation courses for pediatric R1 residents under SCFHS training programs. The striking results are the improvement in all assessed categories of knowledge and practical skills for all the courses, although the retention candidates were few but striking result of significant retaining the practicle skills and even retaining the knowledge as non scored similar or below pre test score. Which makes a strong argument to mandate such courses to all pediatric residents. Further research is needed to study skills’ retention more widelyand more importantly its impact on patients’ care. Although resource-intensive, the use of cumulative evaluation data helped to focus quality improvement in our courses.

Developing 3D interfaces to aid nerve repair

Event Abstract Back to Event Developing 3D interfaces to aid nerve repair Suzanne E. Thomson1, Theophile Dejardin2, Doaa Kredi1, Brian Smith3, Andrew Hart1, Paul Kingham4 and Mathis Riehle1 1 University of Galsgow, Centre for Cell Engineering, United Kingdom 2 CNRS, Université Paris Diderot, Institute Jaques Monod, France 3 University of Glasgow, Institute of Molecular, Cell & Systems Biology, United Kingdom 4 Umeå University, Department of Integrative Medical Biology, Sweden Introduction: Peripheral nerve injury (by trauma, surgery, disease) is fairly common affecting 1/1000 [UK data])[1], treatment is costly and outcomes remain unsatisfactory despite advances in microsurgical repair[2]. Commercially available nerve conduits fail to surpass the current gold standard of autologous nerve graft in the management of a gap defect [3]. The neurobiology of the nerve repair must be unraveled, and our understanding used to improve the current alternatives to autologous nerve graft[4]. The directionality and rate of axonal regrowth following nerve injury can be modulated in vitro by growing cells on micropatterned surfaces, improving neuro-compatibility of interfaces and electrical stimulation[5],[6]. Furthermore adipose derived stem cells, differentiated towards a Schwann like phenotype (ADSC) can be used to support nerve repair[7]. We aim to investigate aspects of all these strategies to further improve the design of a nerve guide. Materials and Methods: Microtopography enhanced microporous membranes were fabricated from polycaprolactone (PCL) and Polydimethylsiloxane (PDMS) by spin coating or casting, and rolled up. 1A) SEM of PCL membrane created by spin coating. 1B) Rolled up guidance tube. Scale 500µm. Surfaces were dip-coated with a surface-active amphiphilic frog foam protein (RSN2) that had been modified to display iLOV, YKVAV or RGD. An organotypic explant model of neonatal rat dorsal root (DRG) ganglion, and isolated neonatal or adult DRG neurons were used to study the effect of the cellular microenvironment on axonal regeneration. ADSC were derived from the abdominal fat of adult rats, derived according to Terenghi et al. (2009) and used to provide a cellular microenvironment. The interaction between signaling elicited by the microenvironment and that activated by growth factors (GFs) was investigated to optimize outcomes. Time dependent gene activation (mTOR, CRAT, MAP3K12) was followed by a targeted qPCR approach. Immohistochemistry was used to study the abundance and localization of target proteins (mTOR, S100, ß3-tubulin). Results: In contrast to a randomly undirected ‘web like’ neurite outgrowth on flat, ß3-tubulin showed directed axons on groove/ridge style microtopography. The differential expression of the target genes studied over a timeline of 10 days showed a maximum activation for mTOR after 2 days. Differentiated adipose derived stem cells adhered to, and proliferated on a PCL surface, whilst maintaining their markers of differentiation. Figure 2A, B) F-actin in ADSC on flat and patterned PCL; scale bar 200µm. S, D) ß3 tubulin in neurites regenerating from DRG on on flat and patterned PCL. YKVAV-RSN2 on PDMS enabled adhesion and neurite outgrowth of neonatal DRG neurons to a similar level as laminin. RGD-RSN2 did support adipose derived Schwann cells, but not individual neurons. PCL membranes supported adhesion and directed outgrowth with microtopography. How, and if ADSC support DRG regeneration within a microstructured scaffold is under investigation. The surface microstructure as well as coating of the scaffold modulated the DRG response to the GF used switching their response. Conclusion(s): These results further characterize a useful in vitro model and provide detail on the complex interactions underlying nerve repair. It highlights some of the downstream effects of micropatterning and explores complimentary bioengineering and GF approaches. A combinatorial approach is planned to incorporate these strategies to bioengineer a novel, cell filled nerve conduit. We would like to thank the Medical Research Council (MRC) UK for funding Suzanne Thomson with a personal fellowship (MR/L017741/1).

Morphometric evaluation of efficacy of modified nerve guidance tubes at bridging large rat sciatic nerve gap: experimental study

Introduction. The primary goal of this experimental study was to evaluate the efficacy of modified nerve guidance tubes and to compare the efficacy of different modifications of intraluminal space of nerve guidance tubes at bridging large rat sciatic nerve gap.Materials and methods. To quantify status of neural fibres we utilized silver impregnation by Bilshovskiy–Gross, to identify myelin sheaths – samples were stained by Spielmeyer.Conclusions. 1. Level of myelination of axons after bridging the gap with hollow guidance tube was the lowest among all other groups of animals and did not depend on regeneration terms. 2. Bridging the gap with different types of modified nerve guidance tubes allowed us to obtain morphometric results reliably equal to “gold standard” of reconstructive surgery – autologous nerve grafting technique.

Experimental verification of the frequency spectrum of unwears and wears guidance tube on the technological head vibrations creation in the production system with AWJ technology

The solution and evaluation of the production system (PS) operation with water jet technology was addressed in more works. It is appropriate to complement this knowledge from works focused on investigation of the other factors effect which affecting the emergence and spread of technological head vibrations, affecting reliability, durability, economic efficiency and operation safe of PS with water jet technology. The article presents experimental investigation results of the vibration acceleration frequency spectrums during cutting steel by unwear and wear rectifying tube with water jet technology. The vibrations size was assessed by two basic vibrations parameters - vibrations frequency and vibration acceleration amplitude.

Phosphate glass fibres and their role in neuronal polarization and axonal growth direction

Phosphate glass fibres with composition 50P2O5–30CaO–9Na2O–3SiO2–3MgO–(5−x)K2O–xTiO2mol.% (x=0, 2.5, 5, respectively coded as TiPS0, TiPS2.5 and TiPS5) were drawn following the preform drawing approach. A 20-day solubility test in bi-distilled water was carried out on glass fibres with different compositions and diameters ranging between 25 and 82μm. The results show that the glass composition, the initial fibre diameter and the thermal treatment are the main factors influencing the dissolution kinetics and that the fibres maintain their structural integrity and composition during dissolution.Biological tests were carried out on aligned TiPS2.5 glass fibres using Neonatal Olfactory Bulb Ensheathing Cell Line (NOBEC) and Dorsal Root Ganglia (DRG) neurons. The fibres showed to be permissive substrates for cell adhesion and proliferation. The aligned configuration of the fibres seemed to provide a directional cue for growing axons of DRG neurons, which showed to sprout and grow long neurites along the fibre axis direction.These promising findings encourages further studies to evaluate the potential use of resorbable glass fibres (e.g.in combination with a nerve guidance tube) for the enhancement of the peripheral nerve healing with the role of supporting and guiding the cells involved in the nerve regeneration.

The Role of Dragon (Repulsive Guidance Molecule-B, RGM-B) in Human Breast Cancer.

Abstract Introduction: Repulsive guidance molecules (RGMs) are involved in embryonic development and iron homeostasis. RGM-A mediates repulsive axonal guidance and neural tube closure, and RGM-C is mutated in juvenile hemochromatosis. RGM-B, also known as Dragon, is a myelin-derived inhibitor of axon growth in the central nervous system. The RGM family was also identified as co-receptors of bone morphogenetic proteins (BMPs), a group of proteins that are involved in development of bones, the differentiation and progression of cancer. However, the role of RGMs played in breast cancer remains unclear. In the present study, we examined the pattern of expression of the RGM family in human breast cancer cells and investigated the impact of Dragon (RGM-B) on BMP-induced cell function in breast cancer cells.Material and Methods: Conventional RT-PCR was performed to screen the expression of RGMs in human breast cancer samples and a range of breast cancer cell lines. Dragon/RGM-B ribozyme transgenes were generated and in order to knock down the Dragon transcript. Subsequently, MDA-231RGMB-Knock-down variants were created by way of the transgenes. A series of cell function assays were employed to investigate any biological effects upon RGM-B knockdown on the breast cancer cells as well as cell's response to recombinant BMP proteins.Results: RGM-A and RGM-C transcripts were barely detectable in breast cancer cell lines (MDA-MB-231 and MCF-7) and tissues. However RGM-B transcripts were expressed in both cell lines. Using anti-RGM-B transgenes, MDA-231RGMB-Knock-down variant cell lines, in which RGM-B transcripts were knocked down, were created. Compared with wild type and control transfection, MDA-231RGMB-Knock-down variants displayed a significant increase in both the adhesiveness and cells growth (p < 0.05, vs the respective controls, for adheresion and for cell growth). Interestingly, RGM-B knockdown did not have any significant effects on the invasiveness of the cells. Finally, wild type breast cancer cells and the RGMB knock down variant cell lines showed a similar response to the treatment with rhBMP-11, indicating that RGM-B is less critical in BMP-11 mediated cell functions.Conclusion: The present study is the first to examine the role of RGM-B in breast cancer and has demonstrated that knock-down of RGMB could enhance breast cancer cells' ability to grow and attach, indicating that RGM-B may act as an inhibitor in breast cancer. This property is unique to RGMB, as this ability is not associated with any other member in the RGM family. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6158.

Controlled release of nerve growth factor from sandwiched poly(L-lactide-co-glycolide) films for the application in neural tissue engineering

In order to fabricate new sustained delivery device of nerve growth factor (NGF), we developed NGFloaded biodegradable poly(L-lactide-co-glycolide) (PLGA, the mole ratio of lactide to glycolide 75∶25, molecular weight: 83,000 and 43,000 g/mole, respectively) film by novel and simple sandwich solvent casting method for the possibility of the application of neural tissue engineering. PLGA was copolymerized by direct condensation reaction and the molecular weight was controlled by reaction time. Released behavior of NGF from NGF-loaded films was characterized by enzyme linked immunosorbent assay (ELISA) and degradation characteristics were observed by scanning electron microscopy (SEM) and gel permeation chromatography (GPC). The bioactivity of released NGF was identified using a rat pheochromocytoma (PC-12) cell based bioassay. The release of NGF from the NGF-loaded PLGA films was prolonged over 35 days with zero-order rate of 0.5∼0.8 ng NGF/day without initial burst and could be controlled by the variations of molecular weight and NGF loading amount. After 7 days NGF released in phosphate buffered saline and PC-12 cell cultured on the NGF-loaded PLGA film for 3 days. The released NGF stimulated neurite sprouting in cultured PC-12 cells, that is to say, the remained NGF in the NGF/PLGA film at 37°C for 7 days was still bioactive. This study suggested that NGF-loaded PLGA sandwich film is released the desired period in delivery system and useful neuronal growth culture as nerve contact guidance tube for the application of neural tissue engineering.

Technological Development Concerning the Gas-Cooled Fast Breeder Reactor Test Bundle for the Irradiation Test in the Helium Loop at Mol

The technological development concerning the 12-rod irradiation test element for the gas-cooled fast breeder reactor irradiation at the BR-2 reactor at Mol, Belgium concentrated on the element head, the sealing problems at the venting manifold, the flow guidance tube, the surface roughening technologies for the cladding, and the rod-spacer interaction. Assembly of a dummy element has shown that the fuel element technology developed can be handled with adequate reliability. For the electrically heated calibration element, a spacer with insulated pads was developed and manufactured full scale. Calibration of the element manufactured is completed.