The role of Patient and public involvement (PPI) in pre-clinical spinal cord research: An interview study

BACKGROUND

Patient and public involvement in research (PPI) has many benefits including increasing relevance and impact. While using PPI in clinical research is now an established practice, the involvement of patients and the public in pre-clinical research, which takes place in a laboratory setting, has been less frequently described and presents specific challenges. This study aimed to explore the perspectives of seriously injured rugby players' who live with a spinal cord injury on PPI in pre-clinical research.

METHODS

Semi-structured interviews were conducted via telephone with 11 seriously injured rugby players living with spinal cord injury on the island of Ireland. A purposive sampling approach was used to identify participants. Selected individuals were invited to take part via gatekeeper in a charitable organisation that supports seriously injured rugby players. Interviews were transcribed verbatim and analysed thematically.

FINDINGS

Six themes were identified during analysis: 'appreciating potential benefits of PPI despite limited knowledge', 'the informed perspectives of people living with spinal cord injury can improve pre-clinical research relevance', 'making pre-clinical research more accessible reduces the potential for misunderstandings to occur', 'barriers to involvement include disinterest, accessibility issues, and fear of losing hope if results are negative', 'personal contact and dialogue helps people feel valued in pre-clinical research, and 'PPI can facilitate effective dissemination of pre-clinical research as desired by people living with spinal cord injury.'

CONCLUSION

People affected by spinal cord injury in this study desire further involvement in pre-clinical spinal cord injury research through dialogue and contact with researchers. Sharing experiences of spinal cord injury can form the basis of PPI for pre-clinical spinal cord injury research.

Knot Architecture for Biocompatible and Semiconducting 2D Electronic Fiber Transistors

Wearable devices have generally been rigid due to their reliance on silicon-based technologies, while future wearables will utilize flexible components for example transistors within microprocessors to manage data. Two-dimensional (2D) semiconducting flakes have yet to be investigated in fiber transistors but can offer a route toward high-mobility, biocompatible, and flexible fiber-based devices. Here, the electrochemical exfoliation of semiconducting 2D flakes of tungsten diselenide (WSe2) and molybdenum disulfide (MoS2) is shown to achieve homogeneous coatings onto the surface of polyester fibers. The high aspect ratio (>100) of the flake yields aligned and conformal flake-to-flake junctions on polyester fibers enabling transistors with mobilities μ ≈1 cm2 V-1 s-1 and a current on/off ratio, Ion/Ioff ≈102-104. Furthermore, the cytotoxic effects of the MoS2 and WSe2 flakes with human keratinocyte cells are investigated and found to be biocompatible. As an additional step, a unique transistor 'knot' architecture is created by leveraging the fiber diameter to establish the length of the transistor channel, facilitating a route to scale down transistor channel dimensions (≈100 µm) and utilize it to make a MoS2 fiber transistor with a human hair that achieves mobilities as high as μ ≈15 cm2 V-1 s-1.

A Biomimetic, Bilayered Antimicrobial Collagen-Based Scaffold for Enhanced Healing of Complex Wound Conditions

Chronic, nonhealing wounds in the form of diabetic foot ulcers (DFUs) are a major complication for diabetic patients. The inability of a DFU to heal appropriately leads to an open wound with a high risk of infection. Current standards of care fail to fully address either the underlying defective wound repair mechanism or the risk of microbial infection. Thus, it is clear that novel approaches are needed. One such approach is the use of multifunctional biomaterials as platforms to direct and promote wound healing. In this study, a biomimetic, bilayered antimicrobial collagen-based scaffold was developed to deal with the etiology of DFUs. An epidermal, antimicrobial collagen/chitosan film for the prevention of wound infection was combined with a dermal collagen-glycosaminoglycan scaffold, which serves to support angiogenesis in the wound environment and ultimately accelerate wound healing. Biophysical and biological characterization identified an 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide cross-linked bilayered scaffold to have the highest structural stability with similar mechanical properties to products on the market, exhibiting a similar structure to native skin, successfully inhibiting the growth and infiltration of Staphylococcus aureus and supporting the proliferation of epidermal cells on its surface. This bilayered scaffold also demonstrated the ability to support the proliferation of key cell types involved in vascularization, namely, induced pluripotent stem cell derived endothelial cells and supporting stromal cells, with early signs of organization of these cells into vascular structures, showing great promise for the promotion of angiogenesis. Taken together, the results indicate that the bilayered scaffold is an excellent candidate for enhancement of diabetic wound healing by preventing wound infection and supporting angiogenesis.

Applying Patient and Public Involvement in preclinical research: A co-created scoping review

BACKGROUND

Patient and Public Involvement (PPI) in research aims to improve the quality, relevance and appropriateness of research. PPI has an established role in clinical research where there is evidence of benefit, and where policymakers and funders place continued emphasis on its inclusion. However, for preclinical research, PPI has not yet achieved the same level of integration. As more researchers, including our team, aim to include PPI in preclinical research, the development of an evidence-based approach is important. Therefore, this scoping review aimed to identify and map studies where PPI has been used in preclinical research and develop principles that can be applied in other projects.

METHODS

A scoping review was conducted to search the literature in Medline (PubMed), EMBASE, CINAHL, PsycInfo and Web of Science Core Collection to identify applied examples of preclinical PPI. Two independent reviewers conducted study selection and data extraction separately. Data were extracted relating to PPI in terms of (i) rationale and aims, (ii) approach used, (iii) benefits and challenges, (iv) impact and evaluation and (v) learning opportunities for preclinical PPI. Findings were reviewed collaboratively by PPI contributors and the research team to identify principles that could be applied to other projects.

RESULTS

Nine studies were included in the final review with the majority of included studies reporting PPI to improve the relevance of their research, using approaches such as PPI advisory panels and workshops. Researchers report several benefits and challenges, although evidence of formal evaluation is limited.

CONCLUSION

Although currently there are few examples of preclinical research studies reporting empirical PPI activity, their findings may support those aiming to use PPI in preclinical research. Through collaborative analysis of the scoping review findings, several principles were developed that may be useful for other preclinical researchers.

PATIENT OR PUBLIC CONTRIBUTION

This study was conducted as part of a broader project aiming to develop an evidence base for preclinical PPI that draws on a 5-year preclinical research programme focused on the development of advanced biomaterials for spinal cord repair as a case study. A PPI Advisory Panel comprising seriously injured rugby players, clinicians, preclinical researchers and PPI facilitators collaborated as co-authors on the conceptualization, execution and writing of this review, including refining the findings into the set of principles reported here.

Highly Conductive Networks of Silver Nanosheets

Although printed networks of semiconducting nanosheets have found success in a range of applications, conductive nanosheet networks are limited by low conductivities (<10⁶ S m^-1 ). Here, dispersions of silver nanosheets (AgNS) that can be printed into highly conductive networks are described. Using a commercial thermal inkjet printer, AgNS patterns with unannealed conductivities of up to (6.0 ± 1.1) × 10⁶  S m^-1 are printed. These networks can form electromagnetic interference shields with record shielding effectiveness of >60 dB in the microwave region at thicknesses <200 nm. High resolution patterns with line widths down to 10 µm are also printed using an aerosol-jet printer which, when annealed at 200 °C, display conductivity >10⁷  S m^-1 . Unlike conventional Ag-nanoparticle inks, the 2D geometry of AgNS yields smooth, short-free interfaces between electrode and active layer when used as the top electrode in vertical nanosheet heterostructures. This shows that all-printed vertical heterostructures of AgNS/WS₂ /AgNS, where the top electrode is a mesh grid, function as photodetectors demonstrating that such structures can be used in optoelectronic applications that usually require transparent conductors.

Perforation-Invagination (PIN) Stripping of the Long Saphenous Vein Reduces Thigh Haematoma Formation in Varicose Vein Surgery

Objective:

To compare the extent of thigh haematoma formation after perforation-invagination (PIN) stripping with that occurring after standard plication stripping of the long saphenous vein.

Design:

Prospective, within-case, randomised study with analysis on an intention-to-treat basis.

Setting:

The radioisotope department of a university teaching hospital.

Patients:

Fourteen patients undergoing bilateral varicose vein surgery.

Interventions:

Red blood cell labelling in vivo with 99Tcm. Preoperative imaging of the long saphenous vein using a gamma camera. Randomisation of one leg to PIN stripping and the other to standard stripping of the long saphenous vein to the knee. Patients were reimaged 6 h postoperatively.

Main outcome measures:

The extent of thigh haematoma formation.

Results:

There was no significant difference with respect to the severity of varicosities in the long saphenous vein in the thigh between the limbs assigned to each group ( n = 11) on the preoperative images ( T = 25, 0.5> p>0.1, Wilcoxon signed rank test). Thigh haematoma in the limbs that had undergone PIN stripping of the long saphenous vein was significantly less than that in the limbs that had undergone standard stripping (T = 10, 0.05> p>0.01, Wilcoxon signed rank test).

Conclusion:

PIN stripping of the long saphenous vein results in significantly decreased haematoma formation compared with standard stripping.

Physical and biological properties of a novel siloxane adhesive for soft tissue applications

The aim of this study was to investigate the adhesive properties of an in-house aminopropyltrimethoxysilane-methylenebisacrylamide (APTMS-MBA) siloxane system and compare them with a commercially available adhesive, n-butyl cyanoacrylate (nBCA). The ability of the material to perform as a soft tissue adhesive was established by measuring the physical (bond strength, curing time) and biological (cytotoxicity) properties of the adhesives on cartilage. Complementary physical techniques, X-ray photoelectron spectroscopy, Raman and infrared imaging, enabled the mode of action of the adhesive to the cartilage surface to be determined. Adhesion strength to cartilage was measured using a simple butt joint test after storage in phosphate-buffered saline solution at 37 degrees C for periods up to 1 month. The adhesives were also characterised using two in vitro biological techniques. A live/dead stain assay enabled a measure of the viability of chondrocytes attached to the two adhesives to be made. A water-soluble tetrazolium assay was carried out using two different cell types, human dermal fibroblasts and ovine meniscal chondrocytes, in order to measure material cytotoxicity as a function of both supernatant concentration and time. IR imaging of the surface of cartilage treated with APTMS-MBA siloxane adhesive indicated that the adhesive penetrated the tissue surface marginally compared to nBCA which showed a greater depth of penetration. The curing time and adhesion strength values for APTMS-MBA siloxane and nBCA adhesives were measured to be 60 s/0.23 MPa and 38 min/0.62 MPa, respectively. These materials were found to be significantly stronger than either commercially available fibrin (0.02 MPa) or gelatin resorcinol formaldehyde (GRF) adhesives (0.1 MPa) (P < 0.01). Cell culture experiments revealed that APTMS-MBA siloxane adhesive induced 2% cell death compared to 95% for the nBCA adhesive, which extended to a depth of approximately 100-150 microm into the cartilage surface. The WST-1 assay demonstrated that APTMS-MBA siloxane was significantly less cytotoxic than nBCA adhesive as an undiluted conditioned supernatant (P < 0.001). These results suggest that the APTMS-MBA siloxane may be a useful adhesive for medical applications.

Synthesis and properties of amphiphilic networks 3: preparation and characterization of block conetworks of poly(butyl methacrylate-block-(2,3 propandiol-1-methacrylate-stat-ethandiol dimethacrylate))

Amphiphilic conetwork polymers were prepared and studied as substrates in the culture of dermal fibroblasts. Both block and random conetworks polymers were produced by radical polymerization of either low-molecular weight monomers or oligomeric macromonomers. The oligomeric macromonomers were prepared by methacrylation of biscarboxy oligo(butyl methacrylates) (OBMA). The latter were synthesized by ozononolysis of poly(butyl methacrylate-co-butadiene) materials. The hydrophilic component was derived from copolymerization with 2,3 propandiol-1-methacrylate and cross-linking was provided by inclusion of ethandiol dimethacrylate (EDMA). None of the synthesized materials showed indications of cytotoxicity to human dermal fibroblasts. All of the block conetworks were highly phase separated and possessed pores on the micron length scale. The equilibrium water contents of the latter could be controlled by addition of EDMA. Block conetworks that did not contain EDMA were highly swollen and had smoother surfaces than those that contained EDMA. The former were poor substrates for cell proliferation (as measured by monitoring DNA content) whilst the latter class gave increasing levels of DNA during culture; an indicator proliferation. The performance of these materials in cell culture was also dependent on the fraction of OBMA in the formulation. Increasing the fractions of BMA, either in the random terpolymer or block networks, system had the effect of increasing both cell proliferation and viability (as measured by the Alamar Blue assay).

A quantitative analysis of the intranasal delivery of topical nasal drugs to the middle meatus: spray versus drop administration

The delivery of nasal drugs specifically to the middle meatus is of critical importance in the medical treatment of rhinosinusitis. In this respect, topical nasal drug administration by drops has generally been perceived to be superior to nasal sprays, although there is a lack of evidence to support this notion. This study aims to compare the intranasal delivery of nasal sprays and drops to the middle meatus in vivo, using a novel quantitative method. A surgical patty was placed in the middle meatus. Radio-labelled topical nasal drops and aqueous sprays were administered in a standardized fashion in normal volunteers (10 nasal cavities). The subsequent absorption of administered radio-labelled saline on the patty was measured using a gamma counter. A randomized prospective crossover design was used for the study. The mean percentage (range) of absorbed administered saline on the swab was 8.7 (0.3-39.5) and 9.7 (0.03-20.4) for the spray and drop administration techniques respectively (p = 0.8). Thus, there is wide variation in the delivery of topical nasal drugs and the perceived superiority of nasal drop administration, in terms of delivery to the middle meatus, may be incorrect.

Effect of radial artery harvesting on tissue perfusion and function of the hand

This study was designed to measure the degree to which hand and forearm blood flow is reduced following harvesting of the radial artery in myocardial revascularization surgery and determine whether there is an effect on hand function. Twenty patients who had the radial artery used for myocardial revascularization underwent bilateral blood flow assessment of hands and forearms using Technetium-99m human serum albumin and clinical evaluation of hand function. Mean tissue perfusion in ml/100 ml/min +/- SD was as follows: donor hand 21.9 +/- 5.6, non-donor hand 25.5 +/- 6.1 (P = 0.00043), donor arm (hand and forearm) 17.5 +/- 3.7 and non-donor arm (hand and forearm) 21 +/- 5.1 (P = 0.000681). No clinical evidence of hand claudication was detected. This study suggests that removal of the radial artery reduces the tissue perfusion of the hand and forearm but does not affect hand function in the short term. The use of radial artery grafts in patients at risk of developing peripheral vascular disease should be carefully considered

Association of simian immunodeficiency virus Nef with the T-cell receptor (TCR) zeta chain leads to TCR down-modulation

The Nef protein of simian immunodeficiency virus (SIV) is dispensable for replication in established T-cell lines but essential for high level virus replication in the adult host, though the mechanism by which Nef contributes to this has remained unclear. We demonstrate here that SIV Nef binds to the zeta chain of the T-cell receptor (TCR). SIV Nef proteins that interact with TCR zeta in a yeast two-hybrid system also reduce T-cell surface expression levels of TCR alphabeta, CD3 and CD4. These findings are the first demonstration that Nef can bind directly to a component of the TCR-CD3 complex and modulate its surface expression.

Perfusion defects in vibration white finger: a clinical assessment using isotope limb blood flow

Vibration white finger is a vasospastic disorder caused by long-term exposure to vibration tools. In an attempt to assess the extent of obliterative vessel disease in this disorder, hyperaemic hand blood flow was measured using technetium-labelled human albumin and a gamma camera. This method quantitates blood flow in ml/100 ml of tissue per min in addition to providing a perfusion image used to assess vessel disease. A perfusion score is then given to this image to reflect the extent of disease. The results of this study demonstrate that 78% of patients with vibration white finger had evidence of organic vessel disease. Moreover, patients with advanced disease tend to be bilaterally affected. The use of this simple method is advocated to aid in the diagnosis of vibration white finger; this may be particularly important for medicolegal purposes.

Radionuclide limb blood flow measurements to resolve diagnostic problems in vascular surgery

This paper describes the application of radionuclide limb blood flow measurements in 60 patients presenting to the vascular surgeons with exercise-induced leg pain. All patients were considered to be diagnostic problems since either their symptoms were atypical for peripheral vascular disease, or they had normal peripheral pulses and/or a normal ankle/brachial pressure index. Thirty-one patients were ultimately shown to have peripheral vascular disease and underwent treatment. In all these cases the limb blood flow to one or both legs was below the normal range. Twenty-three patients were shown, by myelography, computed tomography or plain radiography, to have orthopaedic disease and in all cases their limb blood flow to both legs was within the normal range. In five patients, the limb blood flow was normal and the symptoms spontaneously resolved, no cause for the leg pain having been found (one patient refused angiography). Radionuclide limb blood flow is a simple and reliable diagnostic test which is superior to the assessment of peripheral pulses or their ankle to brachial pressure index in resolving diagnostic problems in vascular surgery.

Hepatic perfusion index: a multicentre trial

The reproducibility and accuracy of the hepatic perfusion index (HPI) was examined by consideration of in vitro and in vivo factors. A phantom was used to simulate liver blood flow and data acquired on nine gamma cameras. Dynamic hepatic scintigraphy was undertaken on 28 patients at two centres and values obtained for the HPI. Results from the phantom study showed good agreement between the nine cameras and also with the HPI values predicted from the measured phantom flow rates. The results of the patient study indicated a high degree of conformity between observers (r = 0.95, S.E = 0.03) but poorer correlation between the HPI values from the two centres (r = 0.67, S.E. = 0.09). These results imply that centres wishing to use HPI clinically should establish their own range of normality.

Pulmonary artery versus left ventricular venting: a radioisotope study of left ventricular function

Radionuclide measurements of ejection fraction were used to assess immediate and late postoperative ventricular function after the use of either a pulmonary artery vent (group A) or a left ventricular vent (group B) in 20 patients undergoing aortic valve replacement for pure aortic stenosis. Ten patients were included in each group and anesthetic techniques, patient management, and septal temperatures were similar in all cases. No significant difference was found between the preoperative and immediate or 6-week postoperative ejection fractions, either taken overall or between the two groups (p greater than 0.05; Student's t test). No correlation was found between cross-clamp time, bypass time, or the occurrence of ventricular fibrillation and the immediate postoperative ejection fraction (p greater than 0.05; Student's t test). There was no significant difference in the incidence of ventricular fibrillation after each type of vent had been used (chi 1(0) = 3.32; p greater than 0.05). We did not demonstrate any abnormalities in regional wall motion associated with apical insertion of a left ventricular vent, and conclude that pulmonary artery and left ventricular vents are equally satisfactory in terms of postoperative ventricular performance.

A simple method of identifying loosening or infection of hip prostheses in nuclear medicine

Joint replacement is now established as a reliable orthopaedic procedure for the relief of many painful degenerative conditions of the hip. When successful it enhances hip movement and relieves pain with a concomitant improvement in function and well being for the patient. When unsuccessful the persistence of pain usually signifies loosening or infection. Loosening may result from mechanical failure or infection. Accurate distinction between septic and aseptic loosening is important for planning and executing surgical intervention. The experience of the Department of Nuclear Medicine in Coventry assessing pathology in painful hip prostheses was retrospectively reviewed in 47 patients. These patients were imaged from 1985 to 1987 and all had good clinical follow-up enabling the diagnosis of loosening, infection or normal to be made with confidence. All patients had three phase bone imaging and some had additional gallium imaging. The images were reviewed with particular emphasis on the pattern of uptake in the late bone image and congruence of abnormal uptake in the early bone image and gallium image. It is concluded that for the majority of patients simple three phase bone imaging will provide the required diagnostic information.

Diagnosis of coronary artery disease using thallium imaging: tomographic versus planar imaging

Coronary artery disease was evaluated with tomographic and planar thallium imaging in 31 subjects who had undergone coronary angiography for assessment of chest pain syndrome. Coronary arteriography revealed significant coronary artery disease in 17; and 14 had normal coronary arteries. The sensitivity and specificity for planar imaging was 71% and 79%, and that for tomography, 94% and 79% respectively. The sensitivity and specificity figures for individual coronary artery lesion detection for planar imaging were 87/83 for LAD, 33/100 for LCX and 50/86 for RCA respectively, and for tomography the figures were 87/87 for LAD, 33/95 for LCX and 90/76 for RCA respectively. The use of coronary arteriography as a gold standard was considered by assessing its interobserver variability, which was 16%. The interobserver variability for thallium imaging was 8% and 3% respectively for tomographic and planar acquisitions.