Functional analysis of protein interactions using coupled bi-fluorescence complementation/GFP nanobody techniques.

Transcription factors (TFs) form homo- or hetero-dimeric DNA binding complexes along with associated co-regulators that can have transcriptional repressor or activator functions. Defining the specific composition of the complexes is therefore key to understanding their biological role. Here, we utilized bimolecular fluorescence complementation (BiFC) to visualize the formation of defined TF dimers and associated co-regulators derived from the activator protein-1 (AP-1) and myocyte enhancer factor 2 (MEF2) families. Firstly, BiFC signals were observed in cells co-expressing TFs tagged with complimentary combinations of the split fluorescent protein, demonstrating the engineered formation of defined dimer complexes. Next, we applied this approach and determined that defined AP-1 dimers localized at discrete sub-nuclear locations. Subsequently, a combination of BiFC coupled with GFP binding peptide (GBP)-nanotrap allowed observation of protein-protein interactions between a co-regulator, HDAC4, and defined BiFC-MEF2 engineered dimers. To determine transactivation properties of defined TF dimers in a cellular system, the Gal4-DNA binding domain fused to GBP was utilized to assess the transcriptional properties of the BiFC-TF dimers using a generically applicable Gal4/UAS luciferase reporter gene assay system. Here, we report efficacy of a BiFC/GBP-nanobody approach that allows engineering, visualization, and functional analysis of defined TF dimers.

Re-organization of nucleolar architecture in myogenic differentiation.

Myogenesis, the process of muscle differentiation, requires an extensive remodeling of the cellular transcriptome and proteome. Whereas the transcriptional program underpinning myogenesis is well characterized, the required adaptation in protein synthesis is incompletely understood. Enhanced protein synthesis necessitates ribosome biogenesis at the nucleolus. Nucleolar size and activity are inextricably linked with altered gene expression. Here, we report changes in nucleolar morphology and function during myogenic differentiation. Immunofluorescence analysis revealed alterations in nucleolar morphology that were dependent on the cellular state - proliferative or quiescent myogenic progenitors (myoblasts or reserve cells) contained multiple small nucleoli with a characteristic spherical shape, whereas multinucleated myotubes typically contained one large, often irregularly shaped nucleolus. These morphological alterations are consistent with changes to nucleolar phase separation properties. Re-organization of the nucleolar structure was correlated with enhanced rRNA production and protein translation. Inhibition of mTOR signaling with rapamycin perturbed nucleolar re-organization. Conversely, hyperactivated mTOR enhanced alterations in nucleolar morphology. These findings support the idea that there is an mTOR dependent re-organization of nucleolar structure during myogenesis, enhancing our understanding of myogenesis and possibly facilitating new approaches to therapeutic interventions in muscle pathologies.

TAZ exhibits phase separation properties and interacts with Smad7 and ß-catenin to repress skeletal myogenesis.

Hippo signaling in Drosophila and mammals is prominent in regulating cell proliferation, death and differentiation. Hippo signaling effectors (YAP and TAZ; also known as YAP1 and WWTR1, respectively) exhibit crosstalk with transforming growth factor-ß (TGF-ß)-Smad and Wnt/ß-catenin pathways. Previously, we implicated Smad7 and ß-catenin in mammalian myogenesis. Therefore, we assessed a potential role of TAZ on the Smad7-ß-catenin complex in muscle cells. Here, we document functional interactions between Smad7, TAZ and ß-catenin in mouse myogenic cells. Ectopic TAZ expression resulted in repression of the muscle-specific creatine kinase muscle (Ckm) gene promoter and its corresponding protein level. Depletion of endogenous TAZ enhanced Ckm promoter activation. Ectopic TAZ, while potently active on a TEAD reporter (HIP-HOP), repressed myogenin (Myog) and Myod1 enhancer regions and myogenin protein level. Additionally, a Wnt/ß-catenin readout (TOP flash) demonstrated TAZ-mediated inhibition of ß-catenin activity. In myoblasts, TAZ was predominantly localized in nuclear speckles, while in differentiation conditions TAZ was hyperphosphorylated at Ser89, leading to enhanced cytoplasmic sequestration. Finally, live-cell imaging indicated that TAZ exhibits properties of liquid-liquid phase separation (LLPS). These observations indicate that TAZ, as an effector of Hippo signaling, suppresses the myogenic differentiation machinery.

Understanding general practitioner and pharmacist preferences for pharmacogenetic testing in primary care: a discrete choice experiment.

Pharmacogenetic testing in the United Kingdom's National Health Service (NHS) has historically been reactive in nature, undertaken in the context of single gene-drug relationships in specialist settings. Using a discrete choice experiment we aimed to identify healthcare professional preferences for development of a pharmacogenetic testing service in primary care in the NHS. Respondents, representing two professions groups (general practitioners or pharmacists), completed one of two survey versions, asking them to select their preferred pharmacogenetic testing service in the context of a presentation of low mood or joint pain. Responses from 235 individuals were included. All respondents preferred pharmacogenetic testing over no testing, though preference heterogeneity was identified. Both professional groups, but especially GPs, were highly sensitive to service design, with uptake varying depending on the service offered. This study demonstrates uptake of a pharmacogenetic testing service is impacted by service design and highlights key areas which should be prioritised within future initiatives.

Public preferences for pharmacogenetic testing in the NHS: Embedding a discrete choice experiment within service design to better meet user needs.

AIMS: Genetic testing can be used to improve the safety and effectiveness of commonly prescribed medicines-a concept known as pharmacogenetics. This study aimed to quantify members of the UK public's preferences for a pharmacogenetic service to be delivered in primary care in the National Health Service. METHODS: Members of the UK population were surveyed via an online panel company. Respondents completed 1 of 2 survey versions, asking respondents to select their preferred pharmacogenetic testing service in the context of a presentation of low mood or pain. A conditional logit model was estimated, before the best functional form for the dataset was identified. Preference heterogeneity was identified via latent class analysis. Coefficients from the final selected models were used to estimate uptake in the context of different hypothetical pharmacogenetic services. RESULTS: Responses from 1993 individuals were included in the analysis. There were no differences observed in preference between the 2 clinical scenarios. Conditional logit analysis, using maximum likelihood estimation, indicated that respondents preferred to have noninvasive tests and wanted their data to be shared between different healthcare organizations to guide future prescribing. There was a preference for regional over national data sharing initiatives, and respondents preferred to have access to their data. Predicted uptake varied considerably, ranging from 51% to >99%, depending on design of the service. CONCLUSION: This study identifies public preferences for a pharmacogenetic testing service and demonstrates how predicted uptake can be impacted by relatively minor adaptations. This highlights areas for prioritization during development of future pharmacogenetic services.

Pharmacogenetics Clinical Decision Support Systems for Primary Care in England: Co-Design Study.

BACKGROUND: Pharmacogenetics can impact patient care and outcomes through personalizing the selection of medicines, resulting in improved efficacy and a reduction in harmful side effects. Despite the existence of compelling clinical evidence and international guidelines highlighting the benefits of pharmacogenetics in clinical practice, implementation within the National Health Service in the United Kingdom is limited. An important barrier to overcome is the development of IT solutions that support the integration of pharmacogenetic data into health care systems. This necessitates a better understanding of the role of electronic health records (EHRs) and the design of clinical decision support systems that are acceptable to clinicians, particularly those in primary care. OBJECTIVE: Explore the needs and requirements of a pharmacogenetic service from the perspective of primary care clinicians with a view to co-design a prototype solution. METHODS: We used ethnographic and think-aloud observations, user research workshops, and prototyping. The participants for this study included general practitioners and pharmacists. In total, we undertook 5 sessions of ethnographic observation to understand current practices and workflows. This was followed by 3 user research workshops, each with its own topic guide starting with personas and early ideation, through to exploring the potential of clinical decision support systems and prototype design. We subsequently analyzed workshop data using affinity diagramming and refined the key requirements for the solution collaboratively as a multidisciplinary project team. RESULTS: User research results identified that pharmacogenetic data must be incorporated within existing EHRs rather than through a stand-alone portal. The information presented through clinical decision support systems must be clear, accessible, and user-friendly as the service will be used by a range of end users. Critically, the information should be displayed within the prescribing workflow, rather than discrete results stored statically in the EHR. Finally, the prescribing recommendations should be authoritative to provide confidence in the validity of the results. Based on these findings we co-designed an interactive prototype, demonstrating pharmacogenetic clinical decision support integrated within the prescribing workflow of an EHR. CONCLUSIONS: This study marks a significant step forward in the design of systems that support pharmacogenetic-guided prescribing in primary care settings. Clinical decision support systems have the potential to enhance the personalization of medicines, provided they are effectively implemented within EHRs and present pharmacogenetic data in a user-friendly, actionable, and standardized format. Achieving this requires the development of a decoupled, standards-based architecture that allows for the separation of data from application, facilitating integration across various EHRs through the use of application programming interfaces (APIs). More globally, this study demonstrates the role of health informatics and user-centered design in realizing the potential of personalized medicine at scale and ensuring that the benefits of genomic innovation reach patients and populations effectively.

Exploring NICU nurses' views of a novel genetic point-of-care test identifying neonates at risk of antibiotic-induced ototoxicity: A qualitative study.

AIM: To explore the views of neonatal intensive care nursing staff on the deliverability of a novel genetic point-of-care test detecting a genetic variant associated with antibiotic-induced ototoxicity. DESIGN: An interpretive, descriptive, qualitative interview study. METHODS: Data were collected using semi-structured interviews undertaken between January and November 2020. Participants were neonatal intensive care nursing staff taking part in the Pharmacogenetics to Avoid Loss of Hearing trial. RESULTS: Thematic analysis resulted in four themes: perceived clinical utility; the golden hour; point-of-care device; training and support. Recommendations were made to streamline the protocol and ongoing training and support were considered key to incorporating the test into routine care. CONCLUSION: Exploring the views of nurses involved in the delivery of the point-of-care test was essential in its implementation. By the study endpoint, all participants could see the value of routine clinical introduction of the point-of care test. IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE: Nurses are in a key position to support the delivery of point-of-care genetic testing into mainstream settings. This study has implications for the successful integration of other genetic point-of-care tests in acute healthcare settings. IMPACT: The study will help to tailor the training and support required for routine deployment of the genetic point-of-care test. The study has relevance for nurses involved in the development and delivery of genetic point-of-care tests in other acute hospital settings. REPORTING METHOD: This qualitative study adheres to the Standards for Reporting Qualitative Research EQUATOR guidelines and utilizes COREQ and SRQR checklists. PATIENT OR PUBLIC CONTRIBUTION: All staff working on the participating neonatal intensive care units were trained to use the genetic point-of-care test. All inpatients on the participating units were eligible to have testing via the point-of-care test. The Pharmacogenetics to Avoid Loss of Hearing Patient and Public Involvement and Engagement group provided valuable feedback. TRIAL AND PROTOCOL REGISTRATION: Registered within the University of Manchester. Ethics approval reference numbers: IRAS: 253102 REC reference: 19/NW/0400. Also registered with the ISRCTN ref: ISRCTN13704894.

Orbital Complication in the Setting of Cocaine Use: A Case Report and Review of Literature.

Orbital cellulitis is a common ophthalmologic consultation and has numerous risk factors; however, one that is seldomly encountered is chronic cocaine use. We describe a case of a 63-year-old man with a history of HIV and cocaine use who presented with OD pain, proptosis, and blurred vision. CT imaging revealed extensive erosions throughout the nasal septum, bilateral turbinates, ethmoid sinuses, and loss of the right medial orbital wall. The patient was treated empirically with broad-spectrum antibiotics, and a nasal biopsy and culture grew Staphylococcus aureus. After treatment with IV antibiotics, the patient's visual acuity returned to baseline with resolution of extraocular motility limitations. Although nasal erosions are a well-described sequela of cocaine use, full-thickness osseous defects of the orbital wall are rare and represent late-stage complications of cocaine-induced destructive midline lesions. Orbital cellulitis is a very rare complication in the setting of cocaine-induced destructive midline lesions. Clinicians should be aware of the link between cocaine use, rhino-orbital abnormalities, and orbital cellulitis.

The impact of machine learning on the prediction of diabetic foot ulcers - A systematic review.

INTRODUCTION: Globally, diabetes mellitus poses a significant health challenge as well as the associated complications of diabetes, such as diabetic foot ulcers (DFUs). The early detection of DFUs is important in the healing process and machine learning may be able to help inform clinical staff during the treatment process. METHODS: A PRISMA-informed search of the literature was completed via the Cochrane Library and MEDLINE (OVID), EMBASE, CINAHL Plus and Scopus databases for reports published in English and in the last ten years. The primary outcome of interest was the impact of machine learning on the prediction of DFUs. The secondary outcome was the statistical performance measures reported. Data were extracted using a predesigned data extraction tool. Quality appraisal was undertaken using the evidence-based librarianship critical appraisal tool. RESULTS: A total of 18 reports met the inclusion criteria. Nine reports proposed models to identify two classes, either healthy skin or a DFU. Nine reports proposed models to predict the progress of DFUs, for example, classing infection versus non-infection, or using wound characteristics to predict healing. A variety of machine learning techniques were proposed. Where reported, sensitivity = 74.53-98 %, accuracy = 64.6-99.32 %, precision = 62.9-99 %, and the F-measure = 52.05-99.0 %. CONCLUSIONS: A variety of machine learning models were suggested to successfully classify DFUs from healthy skin, or to inform the prediction of DFUs. The proposed machine learning models may have the potential to inform the clinical practice of managing DFUs and may help to improve outcomes for individuals with DFUs. Future research may benefit from the development of a standard device and algorithm that detects, diagnoses and predicts the progress of DFUs.

Utility of screening for silent myocardial ischaemia in diabetes with an annual electrocardiogram.

BACKGROUND AND METHODS: Asymptomatic coronary artery disease (CAD) is common in people with diabetes mellitus, but there is a lack of consensus regarding appropriate screening for the condition. We performed a 12-lead electrocardiogram (ECG) on 312 consecutive participants with diabetes mellitus attending for routine annual outpatient review in order to determine the effectiveness of a yearly ECG in screening people with diabetes for asymptomatic CAD. RESULTS: Three of 312 participants (0.96%, 95% CI 0.2%-2.78%) had a newly identified ECG abnormality. One person had newly discovered atrial fibrillation. Two people had abnormalities which prompted further investigation for asymptomatic CAD. One of these participants underwent percutaneous coronary intervention. Seventeen further participants had abnormalities on ECG which had been previously documented, the majority having been present since their diagnosis of diabetes. CONCLUSION: A low positive yield of routine annual ECG in our study does not support its use as a screening tool for asymptomatic CAD in diabetes. Our findings support advice to perform an ECG at diagnosis of diabetes and to repeat only if a person develops relevant symptoms.

Small is Powerful: Demonstration of the Impact of Nanoformed Piroxicam in a Controlled Clinical Study.

PURPOSE: New solutions are needed to enable the efficient use of poorly water-soluble drugs. Therefore, we aimed to demonstrate that decreasing particle size with a solution-to-particle method known as nanoforming can improve dissolution and thus bioavailability. METHODS: Piroxicam, a poorly water-soluble non-steroidal anti-inflammatory drug (NSAID), was used as a model compound. A Quality-by-Design (QbD) approach was used to nanoform piroxicam and a design space was established. The pharmacokinetics of piroxicam nanoparticles were compared to two marketed products in a clinical trial. RESULTS: Nanoformed tablets showed a 33% increase in exposure during the first hour after dosing (AUC0-1 h) compared with an immediate release tablet and was similar to a fast absorbing tablet incorporating complexation of piroxicam with ß-cyclodextrin. CONCLUSIONS: The results show that nanoforming enabled more rapid absorption in comparison to a typical marketed tablet and indicate that nanoforming is an alternative to complex formulation such as cyclodextrins based products. The study outcomes support the potential of nanoforming for producing fast-acting dosage forms of poorly soluble drugs.

First Genotype-Phenotype Study in TBX4 Syndrome: Gain-of-Function Mutations Causative for Lung Disease.

Rationale: Despite the increased recognition of TBX4 (T-BOX transcription factor 4)-associated pulmonary arterial hypertension (PAH), genotype-phenotype associations are lacking and may provide important insights. Objectives: To compile and functionally characterize all TBX4 variants reported to date and undertake a comprehensive genotype-phenotype analysis. Methods: We assembled a multicenter cohort of 137 patients harboring monoallelic TBX4 variants and assessed the pathogenicity of missense variation (n = 42) using a novel luciferase reporter assay containing T-BOX binding motifs. We sought genotype-phenotype correlations and undertook a comparative analysis with patients with PAH with BMPR2 (Bone Morphogenetic Protein Receptor type 2) causal variants (n = 162) or no identified variants in PAH-associated genes (n = 741) genotyped via the National Institute for Health Research BioResource-Rare Diseases. Measurements and Main Results: Functional assessment of TBX4 missense variants led to the novel finding of gain-of-function effects associated with older age at diagnosis of lung disease compared with loss-of-function effects (P = 0.038). Variants located in the T-BOX and nuclear localization domains were associated with earlier presentation (P = 0.005) and increased incidence of interstitial lung disease (P = 0.003). Event-free survival (death or transplantation) was shorter in the T-BOX group (P = 0.022), although age had a significant effect in the hazard model (P = 0.0461). Carriers of TBX4 variants were diagnosed at a younger age (P < 0.001) and had worse baseline lung function (FEV1, FVC) (P = 0.009) than the BMPR2 and no identified causal variant groups. Conclusions: We demonstrated that TBX4 syndrome is not strictly the result of haploinsufficiency but can also be caused by gain of function. The pleiotropic effects of TBX4 in lung disease may be in part explained by the differential effect of pathogenic mutations located in critical protein domains.

The Implementation of Pharmacogenetics in the United Kingdom.

There is considerable inter-individual variability in the effectiveness and safety of pharmaceutical interventions. This phenomenon can be attributed to a multitude of factors; however, it is widely acknowledged that common genetic variation affecting drug absorption or metabolism play a substantial contributory role. This is a concept known as pharmacogenetics. Understanding how common genetic variants influence responses to medications, and using this knowledge to inform prescribing practice, could yield significant advantages for both patients and healthcare systems. Some health services around the world have introduced pharmacogenetics into routine practice, whereas others are less advanced along the implementation pathway. This chapter introduces the field of pharmacogenetics, the existing body of evidence, and discusses barriers to implementation. The chapter will specifically focus on efforts to introduce pharmacogenetics in the NHS, highlighting key challenges related to scale, informatics, and education.

Development of an Aptamer-Based Electrochemical Microfluidic Device for Viral Vaccine Quantitation.

Global deployment of vaccines poses significant challenges in the distribution and use of the accompanying immunoassays, one of the standard methods for quality control of vaccines, particularly when establishing assays in countries worldwide to support testing/release upon importation. This work describes our effort toward developing an integrated, portable device to carry out affinity assays for viral particles quantification in viral vaccines by incorporating (i) aptamers, (ii) microfluidic devices, and (iii) electrochemical detection. We generated and characterized more than eight aptamers against multiple membrane proteins of cytomegalovirus (CMV), which we used as a model system and designed and fabricated electrochemical microfluidic devices to measure CMV concentrations in a candidate vaccine under development. The aptamer-based assays provided a half maximal effective concentration, EC50, of 12 U/mL, comparable to that of an ELISA using a pair of antibodies (EC50 60 U/mL). The device measured relative CMV concentrations accurately (within ±10% bias) and precisely (11%, percent relative standard deviation). This work represents the critical first steps toward developing simple, affordable, and robust affinity assays for global deployment without the need for sensitive equipment and extensive analyst training.

The importance of biological sex in cardiac cachexia.

Cardiac cachexia is a catabolic muscle-wasting syndrome observed in approximately 1 in 10 patients with heart failure. Increased skeletal muscle atrophy leads to frailty and limits mobility, which impacts quality of life, exacerbates clinical care, and is associated with higher rates of mortality. Heart failure is known to exhibit a wide range of prevalence and severity when examined across individuals of different ages and with comorbidities related to diabetes, renal failure, and pulmonary dysfunction. It is also recognized that men and women exhibit striking differences in the pathophysiology of heart failure, as well as skeletal muscle homeostasis. Given that both skeletal muscle and heart failure physiology are in part sex-dependent, the diagnosis and treatment of cachexia in patients with heart failure may depend on a comprehensive examination of how these organs interact. In this review, we explore the potential for sex-specific differences in cardiac cachexia. We summarize advantages and disadvantages of clinical methods used to measure muscle mass and function and provide alternative measurements that should be considered in preclinical studies. In addition, we summarize sex-dependent effects on muscle wasting in preclinical models of heart failure, disuse, and cancer. Lastly, we discuss the endocrine function of the heart and outline unanswered questions that could directly impact patient care.

Patient and public involvement in hearing research: opportunities, impact and reflections with case studies from the Manchester Centre for Audiology and Deafness.

OBJECTIVE: Patient and public involvement (PPI) in research improves relevance to end users and improves processes including recruitment participants. PPI in our research has gone from being non-existent to ubiquitous over a few years. We provide critical reflections on the benefits and challenges of PPI. DESIGN: Case studies are reported according to a modified GRIP2 framework; the aims, methodology, impact of PPI and critical reflections on each case and our experiences with PPI in general. STUDY SAMPLE: We report five UK projects that included PPI from teenagers, families, people living with dementia, autistic people, and people from South Asian and d/Deaf communities. RESULTS: Our experience has progressed from understanding the rationale to grappling methodologies and integrating PPI in our research. PPI took place at all stages of research, although commonly involved input to design including recruitment and development of study materials. Methodologies varied between projects, including PPI co-investigators, advisory panels and online surveys. CONCLUSION: On-going challenges include addressing social exclusion from research for people that lack digital access following increasing on-line PPI and involvement from underserved communities. PPI was initially motivated by funders; however the benefits have driven widespread PPI, ensuring our research is relevant to people living with hearing loss.

TNAP limits TGF-ß-dependent cardiac and skeletal muscle fibrosis by inactivating the SMAD2/3 transcription factors.

Fibrosis is associated with almost all forms of chronic cardiac and skeletal muscle diseases. The accumulation of extracellular matrix impairs the contractility of muscle cells contributing to organ failure. Transforming growth factor ß (TGF-ß) plays a pivotal role in fibrosis, activating pro-fibrotic gene programmes via phosphorylation of SMAD2/3 transcription factors. However, the mechanisms that control de-phosphorylation of SMAD2 and SMAD3 (SMAD2/3) have remained poorly characterized. Here, we show that tissue non-specific alkaline phosphatase (TNAP, also known as ALPL) is highly upregulated in hypertrophic hearts and in dystrophic skeletal muscles, and that the abrogation of TGF-ß signalling in TNAP-positive cells reduces vascular and interstitial fibrosis. We show that TNAP colocalizes and interacts with SMAD2. The TNAP inhibitor MLS-0038949 increases SMAD2/3 phosphorylation, while TNAP overexpression reduces SMAD2/3 phosphorylation and the expression of downstream fibrotic genes. Overall our data demonstrate that TNAP negatively regulates TGF-ß signalling and likely represents a mechanism to limit fibrosis.

New insights into the clinical and molecular spectrum of the novel CYFIP2-related neurodevelopmental disorder and impairment of the WRC-mediated actin dynamics.

PURPOSE: A few de novo missense variants in the cytoplasmic FMRP-interacting protein 2 (CYFIP2) gene have recently been described as a novel cause of severe intellectual disability, seizures, and hypotonia in 18 individuals, with p.Arg87 substitutions in the majority. METHODS: We assembled data from 19 newly identified and all 18 previously published individuals with CYFIP2 variants. By structural modeling and investigation of WAVE-regulatory complex (WRC)-mediated actin polymerization in six patient fibroblast lines we assessed the impact of CYFIP2 variants on the WRC. RESULTS: Sixteen of 19 individuals harbor two previously described and 11 novel (likely) disease-associated missense variants. We report p.Asp724 as second mutational hotspot (4/19 cases). Genotype-phenotype correlation confirms a consistently severe phenotype in p.Arg87 patients but a more variable phenotype in p.Asp724 and other substitutions. Three individuals with milder phenotypes carry putative loss-of-function variants, which remain of unclear pathogenicity. Structural modeling predicted missense variants to disturb interactions within the WRC or impair CYFIP2 stability. Consistent with its role in WRC-mediated actin polymerization we substantiate aberrant regulation of the actin cytoskeleton in patient fibroblasts. CONCLUSION: Our study expands the clinical and molecular spectrum of CYFIP2-related neurodevelopmental disorder and provides evidence for aberrant WRC-mediated actin dynamics as contributing cellular pathomechanism.

Identification of the Most Important Subset of Doppler, Laboratory, and Clinical Parameters for Serial TIPS Evaluation.

OBJECTIVE. The purpose of the present study was to identify the subset of a wide range of serial Doppler, laboratory, and clinical parameters most predictive (both individually and in combination) of TIPS dysfunction in a large patient sample. MATERIALS AND METHODS. The medical records of 189 patients who had undergone TIPS procedures were analyzed. The patients (mean age, 52 years; 62% of whom were men) had undergone 1139 Doppler studies and 323 portovenograms. Laboratory parameters included model for end-stage liver disease (MELD) scores, serum albumin levels, presence of ascites, and time since last intervention. Doppler parameters included intrashunt velocities, temporal change in intrashunt velocities, main portal vein velocity, direction of flow in the left portal hepatic vein, and venous pulsatility index. Statistical analysis used ROC, univariate, and multivariate regression models to assess the parameters both individually and in combination. Shunt dysfunction was defined by a portosystemic gradient of more than 12 mm Hg. RESULTS. The laboratory and clinical parameters of greatest predictive value included the MELD score and the time since the last intervention. The Doppler parameters that were of greatest predictive value included the change in velocity at the hepatic venous end and the left portal vein flow direction. Multivariate models produced an AUC of 0.74. Differences between functional and dysfunctional shunts were also statistically significant for absolute velocity at the hepatic venous end, the change in velocity within the stent, and the temporal change in the mid shunt velocity. CONCLUSION. The subset of serial parameters most predictive of TIPS dysfunction are the temporal change in the velocity at the hepatic venous end, the absolute velocity at the hepatic venous end, the direction of flow in the left portal venous branch, and changes in the MELD score.

Using a biomarker acutely to identify babies at risk of serious adverse effects from antibiotics: where is the 'Terrible Moral and Medical Dilemma'?

We thank Parker and Wright for engaging in this roundtable debate in such a spirited way. The 'Pharmacogenetic [test] to Avoid Loss of Hearing' (PALOH) Trial is the first time a genetic point of care test has been applied in the acute neonatal setting; therefore, it is not surprising that questions have been raised which require debate, discussion and clarification. Parker and Wright misattribute several assumptions to the roundtable authors, which we would like to clarify here. Since they raise wider questions about the PALOH trial itself, several of the roundtable discussants have made a joint response.