Sonographic risk stratification of FDG-avid thyroid nodules using the Thyroid Imaging Reporting and Data System.

INTRODUCTION: The increasing usage of positron emission tomography/computed tomography (PET/CT) for detection and monitoring of malignancy has led to an increase in incidental detection of thyroid nodules. Nodules that demonstrate increased avidity for 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) have been shown to carry a high incidence of malignancy and warrant further investigation. At present, there has been limited research on the risk stratification of FDG-avid thyroid incidentalomas. Thus, this study aims to evaluate the efficacy of the ACR TIRADS classification in the risk stratification of such nodules. METHODS: Data were collected retrospectively for FDG-avid thyroid incidentalomas over a 10-year period. Nodules were characterised using the TIRADS classification and, subsequently, underwent fine-needle aspirate cytology. Cytological findings were classified using the Bethesda reporting system. Non-diagnostic samples (Bethesda class I) were excluded. The remaining samples were divided into two groups: benign (Bethesda class II) or suspicious for malignancy/malignant (Bethesda class III or above). RESULTS: Thirty-six percent of low-risk nodules and 45% of high-risk nodules were malignant, respectively (P = 0.516). The sensitivity and specificity of TIRADS for detection of malignant nodules were 56% and 54%, respectively. There were no malignant TIRADS 1 or 2 nodules. The absence of any suspicious sonographic features had a 1.0 negative predictive value. CONCLUSIONS: FDG-avid nodules classified as TIRADS 1 or 2 or have no suspicious ultrasound features have a 0% incidence of malignancy and thus may not require further assessment with fine-needle aspirate cytology (FNA) when detected incidentally. FDG-avid nodules that are TIRADS 3 or above should undergo FNA regardless of size due to the high risk of malignancy and poor sensitivity of the TIRADS classification system.

Evaluating the druggability of TrmD, a potential antibacterial target, through design and microbiological profiling of a series of potent TrmD inhibitors.

The post-transcriptional modifier tRNA-(N1G37) methyltransferase (TrmD) has been proposed to be essential for growth in many Gram-negative and Gram-positive pathogens, however previously reported inhibitors show only weak antibacterial activity. In this work, optimisation of fragment hits resulted in compounds with low nanomolar TrmD inhibition incorporating features designed to enhance bacterial permeability and covering a range of physicochemical space. The resulting lack of significant antibacterial activity suggests that whilst TrmD is highly ligandable, its essentiality and druggability are called into question.

Identification, binding, and structural characterization of single domain anti-PD-L1 antibodies inhibitory of immune regulatory proteins PD-1 and CD80.

Programmed death-ligand 1 (PD-L1) is a key immune regulatory protein that interacts with programmed cell death protein 1 (PD-1), leading to T-cell suppression. Whilst this interaction is key in self-tolerance, cancer cells evade the immune system by overexpressing PD-L1. Inhibition of the PD-1/PD-L1 pathway with standard monoclonal antibodies has proven a highly effective cancer treatment; however, single domain antibodies (VHH) may offer numerous potential benefits. Here, we report the identification and characterization of a diverse panel of 16 novel VHHs specific to PD-L1. The panel of VHHs demonstrate affinities of 0.7 nM to 5.1 µM and were able to completely inhibit PD-1 binding to PD-L1. The binding site for each VHH on PD-L1 was determined using NMR chemical shift perturbation mapping and revealed a common binding surface encompassing the PD-1-binding site. Additionally, we solved crystal structures of two representative VHHs in complex with PD-L1, which revealed unique binding modes. Similar NMR experiments were used to identify the binding site of CD80 on PD-L1, which is another immune response regulatory element and interacts with PD-L1 localized on the same cell surface. CD80 and PD-1 were revealed to share a highly overlapping binding site on PD-L1, with the panel of VHHs identified expected to inhibit CD80 binding. Comparison of the CD80 and PD-1 binding sites on PD-L1 enabled the identification of a potential antibody binding region able to confer specificity for the inhibition of PD-1 binding only, which may offer therapeutic benefits to counteract cancer cell evasion of the immune system.

Establishing an Ultrasound Screening Protocol for Chronic Liver Disease with a Handheld Device: A Pilot Project in Southern Ethiopia.

Chronic liver disease (CLD) poses significant challenges in the developing world. The prevalence of this problem and the health burden on local health services are not well understood. The diagnosis and monitoring of CLD are difficult in these settings because of limited access to expensive imaging with limited mobility and/or liver biopsy. The aim of this project was to develop and implement an efficient evidence-based robust ultrasound protocol for the assessment of chronic liver disease using a hand-held ultrasound device that could be effectively used in the developing world. A protocol was established using scoring systems that have established accuracy for the diagnosis of hepatic fibrosis/cirrhosis and hepatic steatosis. Included in the protocol was the identification of hepatic masses, portal venous enlargement, hepatic size and splenic size. Hepatic steatosis was common, identified in 46 of 94 participants (49%). Hepatic fibrosis was observed in only 13 of 94 participants (14%). A significant limitation of the methodology was the inability to validate the results with biopsy or other forms of cross-sectional imaging. The protocol was successfully implemented in a community in a rural setting in South Ethiopia with a mean examination time of around 6 min. It is feasible to use handheld ultrasound for the screening of CLD in remote settings. This project provides an evidence-based framework for further studies in this area.

Fragment-based target screening as an empirical approach to prioritising targets: a case study on antibacterials.

Here, we describe a novel workflow combining informatic and experimental approaches to enable evidence-based prioritising of targets from large sets in parallel. High-throughput protein production and biophysical fragment screening is used to identify those targets that are tractable and ligandable. As proof of concept we have applied this to a set of antibacterial targets comprising 146 essential genes. Of these targets, 51 were selected and 38 delivered results that allowed us to rank them by ligandability. The data obtained against these derisked targets have enabled rapid progression into structurally enabled drug discovery projects, demonstrating the practical value of the fragment-based target screening workflow.

Surveillance Practice for Sonographic Detection of Intracranial Abnormalities in Premature Neonates: A Snapshot of Current Neonatal Cranial Ultrasound Practice in Australia.

There are no publications reporting on scan duration and Doppler use during neonatal cranial ultrasound scans. We investigated current practice of neonatal cranial ultrasound at four large tertiary neonatal intensive care units in Australia. Cranial scans were prospectively recorded between March 2015 and November 2016. Variables, including total number of scans, scan duration and frequency and duration of colour and spectral Doppler mode, were extracted. A total of 196 scans formed the final cohort. The median (range) number of scans for each neonate was 1 (1-12). The median (range) overall total scan duration was 309 (119-801) s. Colour mode with or without spectral Doppler mode was used in approximately half of the cohort (106/196, 54%). Our findings comport with our hypotheses. Operators performing neonatal cranial scans in Australia have low overall scan durations. Although the use of Doppler mode during neonatal cranial scans is not standard practice in all neonatal intensive care units, it is used widely irrespective of the degree of prematurity or the presence of brain pathology. Further efforts are required to incorporate recommendations on scan duration and the routine use of Doppler mode during neonatal cranial scans. This is especially imperative given that the most vulnerable neonates with the greater neural tissue sensitivity are likely to be scanned more often.

Accuracy of sonographic estimation of weight in fetuses with abdominal wall defects.

BACKGROUND: Accurate estimation of fetal weight is essential in guiding management of fetuses with abdominal wall defects (AWDs), as growth restriction is an important predictor of perinatal morbidity and mortality. Several sonographic formulae are available involving multiple biometric parameters, but abdominal circumference measurements may underestimate weight in fetuses with AWDs. No formula has yet shown superior accuracy. AIMS: The objectives of this study were to evaluate, in fetuses with gastroschisis and omphalocoele, the accuracy of a sonographic estimated fetal weight (EFW) formula proposed by Siemer and colleagues, specifically for use in fetuses with AWDs compared to the commonly used Hadlock IV formula in estimating fetal weight, and detecting small for gestational age (SGA) fetuses. MATERIALS AND METHODS: A retrospective cohort of 113 fetuses with AWDs was identified from an Australian teaching hospital over 13 years. Pregnancy data and sonographic fetal biometry parameters were obtained. The accuracy of each formula in predicting birthweight was compared using Bland-Altman limits of agreement, and the intraclass correlation coefficient between EFW and actual birthweight. Performance of each formula in detecting SGA fetuses was determined. RESULTS: The Siemer and Hadlock formulae have similar accuracies for predicting birthweight in fetuses with AWDs. The Hadlock formula has a higher detection rate for SGA < 10th centile and < 3rd centile compared to the Seimer formula (84% vs 68% and 83% vs 67% respectively), albeit with a higher false-positive rate. CONCLUSION: There is no clear clinical advantage in using the Siemer formula, which is specifically designed for fetuses with AWDs, over the Hadlock formula to estimate weight in fetuses with AWDs.

Allosteric activation of MALT1 by its ubiquitin-binding Ig3 domain.

The catalytic activity of the protease MALT1 is required for adaptive immune responses and regulatory T (Treg)-cell development, while dysregulated MALT1 activity can lead to lymphoma. MALT1 activation requires its monoubiquitination on lysine 644 (K644) within the Ig3 domain, localized adjacent to the protease domain. The molecular requirements for MALT1 monoubiquitination and the mechanism by which monoubiquitination activates MALT1 had remained elusive. Here, we show that the Ig3 domain interacts directly with ubiquitin and that an intact Ig3-ubiquitin interaction surface is required for the conjugation of ubiquitin to K644. Moreover, by generating constitutively active MALT1 mutants that overcome the need for monoubiquitination, we reveal an allosteric communication between the ubiquitination site K644, the Ig3-protease interaction surface, and the active site of the protease domain. Finally, we show that MALT1 mutants that alter the Ig3-ubiquitin interface impact the biological response of T cells. Thus, ubiquitin binding by the Ig3 domain promotes MALT1 activation by an allosteric mechanism that is essential for its biological function.

Fetal growth and well-being in a study of maternal hypertension in rabbits.

Obtaining growth and physiologic data in the postnatal laboratory animal is common. However, monitoring growth in utero is far more difficult, with little data available except upon termination of pregnancy. High-resolution ultrasound was used to monitor growth, morphology, and fetal well-being in normotensive and hypertensive rabbits (21 fetuses) at day 16, 20, and 26 of the 32 day gestational period. Set protocols, comparable to those routinely assessed in humans, were devised and followed for each examination. Birth weight was greater in offspring of hypertensive as compared to normotensive mothers (p < 0.001); however, litter size was reduced. The greater birth weight was reflected in growth parameters measured throughout gestation indicating the predictive value of ultrasound. High-resolution ultrasound was a reliable and sensitive method for biometric and morphologic assessment of the fetal rabbit, demonstrating that growth trajectory of offspring of hypertensive mothers may be altered early in gestation.

Assessing the value of preoperative medical clearance in patients with primary rhegmatogenous retinal detachment.

PURPOSE: To determine rates of intraoperative and postoperative systemic and ocular adverse events and establish the value of preoperative medical assessment in patients undergoing surgery for primary rhegmatogenous retinal detachment repair at a single academic center. PATIENTS AND METHODS: Retrospective cohort study of 185 patients undergoing surgery for repair of primary rhegmatogenous retinal detachment (RRD) at a single academic center. Medical records were reviewed for medical comorbidities, completion of preoperative medical examination, anesthesia used during surgery, intraoperative adverse medical events, intraoperative ocular complications, and systemic and ocular postoperative complications. The main outcome of interest was the association of comorbidities and preoperative medical evaluation with intraoperative and postoperative complications. RESULTS: Approximately 48% of the patients presented with no medical comorbidities of interest. Formal preoperative evaluation by an independent medical provider was completed in 36% of the patients. Overall, intraoperative and postoperative systemic complications (5.7% and 1%, respectively) and intraoperative and postoperative ocular complications (0.5% for both) were uncommon. Patients with a history of chronic heart failure (OR 24.5, P=0.02) or who received general anesthesia (OR 9.56, P<0.001) had increased risk of having experienced any intraoperative or postoperative complication. No relationship between preoperative medical evaluation and intraoperative and postoperative complications was observed. CONCLUSION: Patients undergoing surgery for RRD repair presented with fewer medical comorbidities than previously reported in patients undergoing all vitreoretinal surgeries. Intraoperative and postoperative complications were uncommon and were increased in patients with chronic heart failure or who received general anesthesia. Complications were not significantly associated with preoperative evaluation by an independent medical provider.

Normal foetal kidney volume in offspring of women treated for gestational diabetes.

AIMS: The worldwide prevalence of gestational diabetes mellitus (GDM) is increasing. Studies in rodent models indicate that hyperglycaemia during pregnancy alters kidney development, yet few studies have examined if this is so in humans. The objective of this study was to evaluate the association of treated GDM with foetal kidney size. MATERIALS AND METHODS: Participants were recruited from an Australian tertiary hospital, and clinical data were collected from women without GDM and women diagnosed and treated for GDM and their offspring. Participants underwent an obstetric ultrasound at 32-34 weeks gestation for foetal biometry and foetal kidney volume measurement. RESULTS: Sixty-four non-GDM and 64 GDM women participated in the study. Thirty percent of GDM women were diagnosed with fasting hyperglycaemia, while 89% had an elevated 2-hour glucose level. Maternal age, weight and body mass index were similar in women with and without GDM. Estimated foetal weight, foetal kidney dimensions, total foetal kidney volume and birth weight were similar in offspring of women with and without GDM. CONCLUSIONS: We conclude that a period of mild hyperglycaemia prior to diagnosis of GDM and treatment initiation, which coincides with a period of rapid nephron formation and kidney growth, does not alter kidney size at 32-34 weeks gestation.

Potent bicyclic inhibitors of malarial cGMP-dependent protein kinase: approaches to combining improvements in cell potency, selectivity and structural novelty.

Focussed studies on imidazopyridine inhibitors of Plasmodium falciparum cyclic GMP-dependent protein kinase (PfPKG) have significantly advanced the series towards desirable in vitro property space. LLE-based approaches towards combining improvements in cell potency, key physicochemical parameters and structural novelty are described, and a structure-based design hypothesis relating to substituent regiochemistry has directed efforts towards key examples with well-balanced potency, ADME and kinase selectivity profiles.

Normal sonographic renal length measurements in an Australian pediatric population.

BACKGROUND: Reference charts depicting normal growth are important for the sonographic assessment of the pediatric kidney. Limited charts are available for clinical use in an Australian population. OBJECTIVE: To retrospectively collate sonographic renal length measurements in a cohort of low-risk Australian children aged newborn to 16 years to produce a reference table and comparison with other published charts. MATERIALS AND METHODS: We identified consecutive pediatric patients who were at low risk for renal disease and had renal lengths measured. After exclusions, we included 941 renal lengths (male 490, female 451). We used linear regression to estimate the relationship of renal length with age, gender and side. We calculated percentile values of renal length according to age categories. RESULTS: No statistically significant differences in mean renal length were observed between males and females, or for left and right kidneys. We tabulated reference data and provide them in a reference chart (1-, 2.5-, 5-, 10-, 50-, 90-, 97.5- and 99-percentiles). CONCLUSION: We calculated new reference ranges for pediatric renal length using a larger cohort than previously published, from a population with diverse ethnicity.

Time to establish pillars in point-of-care ultrasound.

Point of care ultrasound (PoCUS) has evolved rapidly and is used by many medical specialties. We propose five essential pillars of PoCUS that are necessary framework for hospital-based PoCUS training and credentialing programs. The pillars are: governance, infrastructure, administration, education and quality. It is time to establish these pillars to ensure the best practice in PoCUS use.

Potent inhibitors of malarial P. Falciparum protein kinase G: Improving the cell activity of a series of imidazopyridines.

Development of a class of bicyclic inhibitors of the Plasmodium falciparum cyclic GMP-dependent protein kinase (PfPKG), starting from known compounds with activity against a related parasite PKG orthologue, is reported. Examination of key sub-structural elements led to new compounds with good levels of inhibitory activity against the recombinant kinase and in vitro activity against the parasite. Key examples were shown to possess encouraging in vitro ADME properties, and computational analysis provided valuable insight into the origins of the observed activity profiles.

Biparietal diameter measurements using the outer-to-outer versus outer-to-inner measurement: A question of pedantry?

OBJECTIVES: To compare two methods of measuring fetal biparietal diameter (BPD) - outer-to-inner (BPDoi) vs. outer-to-outer (BPDoo) calliper placement - and to compare the differences in EFW calculated using the Hadlock 4 formula and other common EFW formulae. METHODS: A total of 543 fetuses underwent a single ultrasound prospectively performed by 40 sonographers between 14 and 40 weeks of gestation, taking into account the intra- and inter-observer variability. The measurements for each fetus consisted of BPDoi and BPDoo, and EFW is calculated from HC, AC and FL measurements. The difference between BPDoo and BPDoi was estimated, and this difference was compared with gestational age using linear regression. Translational equations that allow interconversion of the two parameters were derived. EFW calculated from four different formulae using various combinations of biometric measurements was compared. RESULTS: The difference between BPDoi and BPDoo increases with gestational age, although this difference was small. For BPDoo, the regression equation is BPDoo = 0.555934 + 1.027318 × BPDoi. Similarly, for BPDoi, the regression equation is BPDoi = -0.403458 + 0.9714153 × BPDoo. There is a minimal difference in the EFW calculated from the four formulae, except for gestations prior to 27-28 weeks. EFW derived from INTERGROWTH-21st formulae plot is higher than that from Hadlock 3 or Hadlock 4 before 27-28 weeks. CONCLUSIONS: Although the absolute difference between BPDoo and BPDoi increased across gestational age, this difference was small. The method of BPD measurement should follow that as prescribed in the EFW equation used in the local context. Estimation of fetal weight using Hadlock 3, Hadlock 4 and INTERGROWTH-21st is similar, with slight differences at gestations less than 27-28 weeks.

Collaborative model for training and credentialing point-of-care ultrasound: 6-year experience and quality outcomes.

INTRODUCTION: Point-of-care ultrasound (PoCUS) is a rapidly growing area, providing physicians with a valuable diagnostic tool for patient assessment. This paper describes a collaborative model, utilising radiology department ultrasound expertise, to train and credential physicians in PoCUS. A 6-year experience of the implementation and outcomes of the programme established within the emergency departments of a large, multi-campus hospital network are presented. METHODS: A collaborative model was initially developed and implemented between radiology and emergency departments. Key elements of the programme included hospital executive support, close collaboration with stakeholders, resource allocation, appointment of a sonographer educator, clear scope of practise and robust quality processes. RESULTS: Participation grew from 36 emergency physicians in 2011 to 96 physicians in 2016. A total 11064 scans were logged with the programme in the 6-year period. Routine quality audit of 61.8% (6836/11064) of all scans included 2836 Focussed Assessment by Sonography in Trauma (FAST) and 1422 Abdominal Aortic Aneurysm (AAA) examinations. False-positive or false-negative diagnoses occurred in 3.6% (102/2836) FAST and 1.3% (19/1422) AAA cases. No adverse clinical outcomes were reported to involve programme-compliant scans. CONCLUSION: A collaborative model to train and credential physicians in PoCUS has been successfully implemented. The programme grew significantly, produced excellent quality outcomes and resolved many issues of potential conflict related to PoCUS.

Knowledge of Safety, Training, and Practice of Neonatal Cranial Ultrasound: A Survey of Operators.

OBJECTIVES: Ultrasound can lead to thermal and mechanical effects in interrogated tissues. This possibility suggests a potential risk during neonatal cranial ultrasound examinations. The aim of this study was to explore safety knowledge and training of neonatal cranial ultrasound among Australian operators who routinely perform these scans. METHODS: An online survey was administered on biosafety and training in neonatal cranial ultrasound, targeting all relevant professionals who can perform neonatal cranial ultrasound examinations in Australia: namely, radiologists, neonatologists, sonographers, and pediatricians. The survey was conducted between November 2013 and May 2014. RESULTS: A total of 282 responses were received. Twenty of 208 (10%) answered all ultrasound biosafety questions correctly, and 49 of 169 (29%) correctly defined the thermal index. Two-thirds (134 of 214 [63%]) of respondents failed to recognize that reducing the overall scanning time is the most effective method of reducing the total power exposure. Only 13% (31 of 237) indicated that a predetermined fixed period of training or that a specified minimum number of supervised scans was used during training. The reported number of supervised scans during training was highly variable. Almost half of the participants (82 of 181 [45%]) stated that they had received supervision for 10 to 50 scans (median, 20 scans). CONCLUSIONS: There is a need to educate operators on biosafety issues and approaches to minimize power outputs and reduce the overall duration of cranial ultrasound scans. Development of standardized training requirements may be warranted.

Characterization of Three Druggable Hot-Spots in the Aurora-A/TPX2 Interaction Using Biochemical, Biophysical, and Fragment-Based Approaches.

The mitotic kinase Aurora-A and its partner protein TPX2 (Targeting Protein for Xenopus kinesin-like protein 2) are overexpressed in cancers, and it has been proposed that they work together as an oncogenic holoenzyme. TPX2 is responsible for activating Aurora-A during mitosis, ensuring proper cell division. Disruption of the interface with TPX2 is therefore a potential target for novel anticancer drugs that exploit the increased sensitivity of cancer cells to mitotic stress. Here, we investigate the interface using coprecipitation assays and isothermal titration calorimetry to quantify the energetic contribution of individual residues of TPX2. Residues Tyr8, Tyr10, Phe16, and Trp34 of TPX2 are shown to be crucial for robust complex formation, suggesting that the interaction could be abrogated through blocking any of the three pockets on Aurora-A that complement these residues. Phosphorylation of Aurora-A on Thr288 is also necessary for high-affinity binding, and here we identify arginine residues that communicate the phosphorylation of Thr288 to the TPX2 binding site. With these findings in mind, we conducted a high-throughput X-ray crystallography-based screen of 1255 fragments against Aurora-A and identified 59 hits. Over three-quarters of these hits bound to the pockets described above, both validating our identification of hotspots and demonstrating the druggability of this protein-protein interaction. Our study exemplifies the potential of high-throughput crystallography facilities such as XChem to aid drug discovery. These results will accelerate the development of chemical inhibitors of the Aurora-A/TPX2 interaction.