Probing ligands to reaction centers to limit the photocycle in photosynthetic bacterium Rubrivivax gelatinosus.

Light-induced electron flow between reaction center and cytochrome bc1 complexes is mediated by quinones and electron donors in purple photosynthetic bacteria. Upon high-intensity excitation, the contribution of the cytochrome bc1 complex is limited kinetically and the electron supply should be provided by the pool of reduced electron donors. The kinetic limitation of electron shuttle between reaction center and cytochrome bc1 complex and its consequences on the photocycle were studied by tracking the redox changes of the primary electron donor (BChl dimer) via absorption change and the opening of the closed reaction center via relaxation of the bacteriochlorophyll fluorescence in intact cells of wild type and pufC mutant strains of Rubrivivax gelatinosus. The results were simulated by a minimum model of reversible binding of different ligands (internal and external electron donors and inhibitors) to donor and acceptor sides of the reaction center. The calculated binding and kinetic parameters revealed that control of the rate of the photocycle is primarily due to 1) the light intensity, 2) the size and redox state of the donor pool, and 3) the unbinding rates of the oxidized donor and inhibitor from the reaction center. The similar kinetics of strains WT and pufC lacking the tetraheme cytochrome subunit attached to the reaction center raise the issue of the physiological importance of this subunit discussed from different points of view. SIGNIFICANCE: A crucial factor for the efficacy of electron donors in photosynthetic photocycle is not just the substantial size of the pool and large binding affinity (small dissociation constant KD = koff/kon) to the RC, but also the mean residence time (koff)-1 in the binding pocket. This is an important parameter that regulates the time of re-activation of the RC during multiple turnovers. The determination of koff has proven challenging and was performed by simulation of widespread experimental data on the kinetics of P+ and relaxation of fluorescence. This work is a step towards better understanding the complex pathways of electron transfer in proteins and simulation-based design of more effective electron transfer components in natural and artificial systems.

Enhancing the ATra Black Box Matching Algorithm: Use of All Names for Deduplication Across Jurisdictions.

OBJECTIVES: Achieving accurate, timely, and complete HIV surveillance data is complicated in the United States by migration and care seeking across jurisdictional boundaries. To address these issues, public health entities use the ATra Black Box-a secure, electronic, privacy-assuring system developed by Georgetown University-to identify and confirm potential duplicate case records, exchange data, and perform other analytics to improve the quality of data in the Enhanced HIV/AIDS Reporting System (eHARS). We aimed to evaluate the ability of 2 ATra software algorithms to identify potential duplicate case-pairs across 6 jurisdictions for people living with diagnosed HIV. METHODS: We implemented 2 matching algorithms for identifying potential duplicate case-pairs in ATra software. The Single Name Matching Algorithm examines only 1 name for a person, whereas the All Names Matching Algorithm examines all names in eHARS for a person. Six public health jurisdictions used the algorithms. We compared outputs for the overall number of potential matches and changes in matching level. RESULTS: The All Names Matching Algorithm found more matches than the Single Name Matching Algorithm and increased levels of match. The All Names Matching Algorithm identified 9070 (4.5%) more duplicate matches than the Single Name Matching Algorithm (n = 198 828) and increased the total number of matches at the exact through high levels by 15.4% (from 167 156 to 192 932; n = 25 776). CONCLUSIONS: HIV data quality across multiple jurisdictions can be improved by using all known first and last names of people living with diagnosed HIV that match with eHARS rather than using only 1 first and last name.

Rapid Deployment of a Free, Privacy-Assured COVID-19 Symptom Tracker for Public Safety During Reopening: System Development and Feasibility Study.

BACKGROUND: Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the number of cases of coronavirus disease (COVID-19) in the United States has exponentially increased. Identifying and monitoring individuals with COVID-19 and individuals who have been exposed to the disease is critical to prevent transmission. Traditional contact tracing mechanisms are not structured on the scale needed to address this pandemic. As businesses reopen, institutions and agencies not traditionally engaged in disease prevention are being tasked with ensuring public safety. Systems to support organizations facing these new challenges are critically needed. Most currently available symptom trackers use a direct-to-consumer approach and use personal identifiers, which raises privacy concerns. OBJECTIVE: Our aim was to develop a monitoring and reporting system for COVID-19 to support institutions conducting monitoring activities without compromising privacy. METHODS: Our multidisciplinary team designed a symptom tracking system after consultation with experts. The system was designed in the Georgetown University AvesTerra knowledge management environment, which supports data integration and synthesis to identify actionable events and maintain privacy. We conducted a beta test for functionality among consenting Georgetown University medical students. RESULTS: The symptom tracker system was designed based on guiding principles developed during peer consultations. Institutions are provided access to the system through an efficient onboarding process that uses clickwrap technology to document agreement to limited terms of use to rapidly enable free access. Institutions provide their constituents with a unique identifier to enter data through a web-based user interface to collect vetted symptoms as well as clinical and epidemiologic data. The website also provides individuals with educational information through links to the COVID-19 prevention recommendations from the US Centers for Disease Control and Prevention. Safety features include instructions for people with new or worsening symptoms to seek care. No personal identifiers are collected in the system. The reporter mechanism safeguards data access so that institutions can only access their own data, and it provides institutions with on-demand access to the data entered by their constituents, organized in summary reports that highlight actionable data. Development of the system began on March 15, 2020, and it was launched on March 20, 2020. In the beta test, 48 Georgetown University School of Medicine students or their social contacts entered data into the system from March 31 to April 5, 2020. One of the 48 users (2%) reported active COVID-19 infection and had no symptoms by the end of the monitoring period. No other participants reported symptoms. Only data with the unique entity identifier for our beta test were generated in our summary reports. CONCLUSIONS: This system harnesses insights into privacy and data sharing to avoid regulatory and legal hurdles to rapid adaption by entities tasked with maintaining public safety. Our pilot study demonstrated feasibility and ease of use. Refinements based on feedback from early adapters included release of a Spanish language version. These systems provide technological advances to complement the traditional contact tracing and digital tracing applications being implemented to limit SARS-CoV-2 transmission during reopening.

Additional Value of Dynamic Contrast-enhanced Sequences in Multiparametric Prostate Magnetic Resonance Imaging: Data from the PROMIS Study.

BACKGROUND: Multiparametric magnetic resonance imaging (MP-MRI) is established in the diagnosis of prostate cancer, but the need for enhanced sequences has recently been questioned. OBJECTIVE: To assess whether dynamic contrast-enhanced imaging (DCE) improves accuracy over T2 and diffusion sequences. DESIGN, SETTING, AND PARTICIPANTS: PROMIS was a multicentre, multireader trial, with, in this part, 497 biopsy-naïve men undergoing standardised 1.5T MP-MRI using T2, diffusion, and DCE, followed by a detailed transperineal prostate mapping (TPM) biopsy at 5 mm intervals. Likert scores of 1-5 for the presence of a significant tumour were assigned in strict sequence, for (1) T2 + diffusion and then (2) T2 + diffusion + dynamic contrast-enhanced images. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: For the primary analysis, the primary PROMIS outcome measure (Gleason score ≥4 + 3 or ≥6 mm maximum cancer length) on TPM was used, and an MRI score of ≥3 was considered positive. RESULTS AND LIMITATIONS: Sensitivity without and with DCE was 94% and 95%, specificity 37% and 38%, positive predictive value 51% and 51%, and negative predictive value 90% and 91%, respectively (p > 0.05 in each case). The number of patients avoiding biopsy (scoring 1-2) was similar (123/497 vs 121/497, p = 0.8). The number of equivocal scores (3/5) was slightly higher without DCE (32% vs 28% p = 0.031). The proportion of MRI equivocal (3/5) and positive (4-5) cases showing significant tumours were similar (23% and 71% vs 20% and 69%). No cases of dominant Gleason 4 or higher were missed with DCE, compared with a single case with T2 + diffusion-weighted imaging. No attempt was made to correlate lesion location on MRI and histology, which may be considered a limitation. Radiologists were aware of the patient's prostate-specific antigen. CONCLUSIONS: Contrast adds little when MP-MRI is used to exclude significant prostate cancer. PATIENT SUMMARY: An intravenous injection of contrast may not be necessary when magnetic resonance imaging is used as a test to rule out significant tumours in the prostate.

Influence of common clinical variables on intraoperative parathyroid hormone monitoring during surgery for primary hyperparathyroidism.

BACKGROUND: Intraoperative monitoring of parathyroid hormone (IOPTH) is a reliable method of predicting the cure of primary hyperparathyroidism (PHPT). The aim of this study is to assess whether common clinical variables (CCV) frequently encountered in patients with PHPT may affect the magnitude of PTH drop or the likelihood of patients meeting the intraoperative cure criterion. DESIGN: Patients who were surgically cured from PHPT caused by single gland disease (SGD) and had full IOPTH protocol (4 measurements) were stratified according to age, gland weight, renal function, vitamin D status and severity of hypercalcemia. The percentage of IOPTH drop and the frequency of patients who had true positive IOPTH test results were compared among groups. RESULTS: 762 patients had surgery for PHPT, of whom 746 were (98%) cured. Of these 746 patients, 511 who had SGD and a full IOPTH protocol were included in this study. The median IOPTH drop was significantly higher among younger patients, those with severe hypercalcaemia at 5, 10, 15 min after gland excision, giant glands (at 5-min only), patients with vitamin D deficiency (at 10, 15 min), and those with normal renal function (at 15 min only). The likelihood of the patients meeting the intraoperative cure criterion was not significantly affected among the groups except in patients with mild hypercalcaemia, who were significantly less likely to have 50% IOPTH drop than those with severe hypercalcaemia at all time points. The frequency of mildly hypercalcaemic patients who met cure criterion was significantly improved by extending measurement to 15 min. CONCLUSIONS: IOPTH monitoring has the ability to mitigate the variability of IOPTH kinetics associated with most clinical variables. Mildly hypercalcemic patients in particular may benefit from waiting for 15-min measurement before any surgical decision is made.

Data Resource: population level family justice administrative data with opportunities for data linkage.

INTRODUCTION: Although there has been considerable progress in the use of administrative data for applied health research, the family justice field lags behind. Better use of administrative data are essential to enhance understanding of how the family justice system is working, as well as the characteristics of, and outcomes for, children and families. The Family Justice Data Partnership (FJDP) supports this aim through analyses of core family justice and linked datasets in the SAIL Databank (Secure Anonymised Information Linkage). Cafcass Cymru provide expert advice for children involved in family court proceedings in Wales, ensuring decisions are made in the best interests of the child. We provide an overview of Cafcass Cymru data. We also describe and illustrate linkage to administrative datasets within SAIL. METHODS: Cafcass Cymru data was transferred to SAIL using a standardised approach to provide de-identified data with Anonymised Linking Fields (ALF) for successfully matched records. Three cohorts were created: all individuals involved in family court applications; all individuals with an ALF allowing subsequent health data linkage; and all individuals with a Residential Anonymised Linking Field (RALF) enabling area-level deprivation analysis. RESULTS: Cafcass Cymru application data are available for child protection matters (public law, range 2011-2019, n=12,745), and child arrangement disputes (private law, range 2005-2019, n=52,023). An 80% data linkage match rate was achieved. 40% had hospital admissions within two years pre or post application; 54% had emergency department attendances and 61% had outpatient appointments. Individuals were more likely to reside in deprived areas regardless of law type. CONCLUSION: Cafcass Cymru data can be accessed through the SAIL Databank. The FJDP will continue to enhance research opportunities for all to better understand the family justice system, and outcomes for those involved, such as health and wellbeing for children and family members.

Improving HIV Surveillance Data by Using the ATra Black Box System to Assist Regional Deduplication Activities.

BACKGROUND: Focused attention on Data to Care underlines the importance of high-quality HIV surveillance data. This study identified the number of total duplicate and exact duplicate HIV case records in 9 separate Enhanced HIV/AIDS Reporting System (eHARS) databases reported by 8 jurisdictions and compared this approach to traditional Routine Interstate Duplicate Review resolution. METHODS: This study used the ATra Black Box System and 6 eHARS variables for matching case records across jurisdictions: last name, first name, date of birth, sex assigned at birth (birth sex), social security number, and race/ethnicity, plus 4 system-calculated values (first name Soundex, last name Soundex, partial date of birth, and partial social security number). RESULTS: In approximately 11 hours, this study matched 290,482 cases from 799,326 uploaded records, including 55,460 exact case pairs. Top case pair overlaps were between NYC and NYS (51%), DC and MD (10%), and FL and NYC (6%), followed closely by FL and NYS (4%), FL and NC (3%), DC and VA (3%), and MD and VA (3%). Jurisdictions estimated that they realized a combined 135 labor hours in time efficiency by using this approach compared with manual methods previously used for interstate duplication resolution. DISCUSSION: This approach discovered exact matches that were not previously identified. It also decreased time spent resolving duplicated case records across jurisdictions while improving accuracy and completeness of HIV surveillance data in support of public health program policies. Future uses of this approach should consider standardized protocols for postprocessing eHARS data.

Update of the activity of telavancin against a global collection of Staphylococcus aureus causing bacteremia, including endocarditis (2011-2014).

The efficacy and safety of telavancin is under evaluation for the treatment of subjects with complicated Staphylococcus aureus bacteremia and S. aureus right-sided infective endocarditis. This study evaluated the telavancin activity against a global collection of S. aureus causing bloodstream infections (BSI), including endocarditis, to support the development of bacteremia/endocarditis clinical indications. This study included a total of 4191 S. aureus [1490 methicillin-resistant S. aureus (MRSA)], which were unique (one per patient) clinical isolates recovered from blood samples collected during 2011-2014 in a global network of hospitals. All isolates were deemed responsible for BSI, including endocarditis, by local guidelines. Isolates were tested for susceptibility by broth microdilution. Telavancin (MIC50/90, 0.03/0.06 µg/ml) inhibited all S. aureus at ≤0.12 µg/ml, the breakpoint for susceptibility. Equivalent minimum inhibitory concentration (MIC) values (MIC50/90, 0.03/0.06 µg/ml) were obtained for telavancin against methicillin-susceptible S. aureus (MSSA) and MRSA isolates, as well as MRSA from community and healthcare origins. Similar telavancin activities (MIC50, 0.03 µg/ml) were observed against MRSA subsets from North America and Europe, while isolates from the Asia-Pacific (APAC) and Latin America regions had MIC50 values of 0.06 µg/ml. MRSA with vancomycin MIC values of 2-4 µg/ml and the multidrug resistance (MDR) subset had telavancin MIC50 results of 0.06 µg/ml, although the MIC100 result obtained against these subsets remained identical to those of MSSA (MIC100, 0.12 µg/ml, respectively). This study updates the telavancin in vitro activity, which continues to demonstrate great potency against invasive S. aureus, regardless of the susceptibility phenotype or demographic characteristics (100.0% susceptible), and supports the sought-after subsequent indications.

Improving HIV Surveillance Data for Public Health Action in Washington, DC: A Novel Multiorganizational Data-Sharing Method.

BACKGROUND: The National HIV/AIDS Strategy calls for active surveillance programs for human immunodeficiency virus (HIV) to more accurately measure access to and retention in care across the HIV care continuum for persons living with HIV within their jurisdictions and to identify persons who may need public health services. However, traditional public health surveillance methods face substantial technological and privacy-related barriers to data sharing. OBJECTIVE: This study developed a novel data-sharing approach to improve the timeliness and quality of HIV surveillance data in three jurisdictions where persons may often travel across the borders of the District of Columbia, Maryland, and Virginia. METHODS: A deterministic algorithm of approximately 1000 lines was developed, including a person-matching system with Enhanced HIV/AIDS Reporting System (eHARS) variables. Person matching was defined in categories (from strongest to weakest): exact, very high, high, medium high, medium, medium low, low, and very low. The algorithm was verified using conventional component testing methods, manual code inspection, and comprehensive output file examination. Results were validated by jurisdictions using internal review processes. RESULTS: Of 161,343 uploaded eHARS records from District of Columbia (N=49,326), Maryland (N=66,200), and Virginia (N=45,817), a total of 21,472 persons were matched across jurisdictions over various strengths in a matching process totaling 21 minutes and 58 seconds in the privacy device, leaving 139,871 uniquely identified with only one jurisdiction. No records matched as medium low or low. Over 80% of the matches were identified as either exact or very high matches. Three separate validation methods were conducted for this study, and they all found ≥90% accuracy between records matched by this novel method and traditional matching methods. CONCLUSIONS: This study illustrated a novel data-sharing approach that may facilitate timelier and better quality HIV surveillance data for public health action by reducing the effort needed for traditional person-matching reviews without compromising matching accuracy. Future analyses will examine the generalizability of these findings to other applications.

Life histories of two deep-water Australian endemic elasmobranchs: Argus skate Dipturus polyommata and eastern spotted gummy shark Mustelus walkeri.

Two Australian endemic elasmobranchs, the Argus skate Dipturus polyommata and the eastern spotted gummy shark Mustelus walkeri, were collected from the by-catch of a prawn Melicertus plebejus trawl fishery off Queensland. Age and growth parameters were estimated from growth band counts in vertebral sections of 220 D. polyommata and 44 M. walkeri. Dipturus polyommata males and females had an observed maximum age of 10 years and reached maximum sizes of 369 and 371 mm total length (LT ), respectively. Mustelus walkeri lived longer, with the oldest female aged 16 years and measuring 1050 mm stretched total length (LST ), and oldest male aged 9 years and 805 mm LST . Dipturus polyommata grew relatively fast with a von Bertalanffy growth completion parameter of k = 0·208 year(-1) with males reaching maturity at 4·0 years (c. 278 mm LT ) and females at 5·1 years (c. 305 mm LT ). Mustelus walkeri grew more slowly with k = 0·033 year(-1) with males estimated to mature at 7-9 years (670-805 mm LST ) and females at 10-14 years (833-1012 mm LST ). Length at birth inferred from neonate D. polyommata was 89-111 mm LT while for M. walkeri it was estimated to be 273 LST based on the value of L0 from the von Bertalanffy growth model. Both species appeared to have continuous reproductive cycles and low fecundity with an average ovarian fecundity of eight follicles for D. polyommata and a litter size of five to seven pups for M. walkeri. Based on these life-history traits, D. polyommata is more resilient to fishing pressure than M. walkeri.

Does real-time objective feedback and competition improve performance and quality in manikin CPR training--a prospective observational study from several European EMS.

BACKGROUND: Previous studies have reported that the quality of cardiopulmonary resuscitation (CPR) is important for patient survival. Real time objective feedback during manikin training has been shown to improve CPR performance. Objective measurement could facilitate competition and help motivate participants to improve their CPR performance. The aims of this study were to investigate whether real time objective feedback on manikins helps improve CPR performance and whether competition between separate European Emergency Medical Services (EMS) and between participants at each EMS helps motivation to train. METHODS: Ten European EMS took part in the study and was carried out in two stages. At Stage 1, each EMS provided 20 pre-hospital professionals. A questionnaire was completed and standardised assessment scenarios were performed for adult and infant out of hospital cardiac arrest (OHCA). CPR performance was objectively measured and recorded but no feedback given. Between Stage 1 and 2, each EMS was given access to manikins for 6 months and instructed on how to use with objective real-time CPR feedback available. Stage 2 was undertaken and was a repeat of Stage 1 with a questionnaire with additional questions relating to usefulness of feedback and the competition nature of the study (using a 10 point Likert score). The EMS that improved the most from Stage 1 to Stage 2 was declared the winner. An independent samples Student t-test was used to analyse the objective CPR metrics with the significance level taken as p < 0.05. RESULTS: Overall mean Improvement of CPR performance from Stage 1 to Stage 2 was significant. The improvement was greater for the infant assessment. The participants thought the real-time feedback very useful (mean score of 8.5) and very easy to use (mean score of 8.2). Competition between EMS organisations recorded a mean score of 5.8 and competition between participants recorded a mean score of 6.0. CONCLUSIONS: The results suggest that the use of real time objective feedback can significantly help improve CPR performance. Competition, especially between participants, appeared to encourage staff to practice and this study suggests that competition might have a useful role to help motivate staff to perform CPR training.

Cytotoxicity, phytochemical analysis and antioxidant activity of crude extracts from rhizomes of Elephantorrhiza elephantina and Pentanisia prunelloides.

BACKGROUND: Elephantorrhiza elephantina (Ee) and Pentanisia prunelloides (Pp) are two medicinal plants which are widely used to remedy various ailments including diarrhoea, dysentery, inflammation, fever, rheumatism, heartburn, tuberculosis, haemorrhoids, skin diseases, perforated peptic ulcers and sore joints in southern Africa (South Africa, Swaziland, Botswana and Zimbabwe). The following study was conducted to explore the in vitro cytotoxicity, antioxidant properties and phytochemical profile of the two medicinal plants. MATERIALS AND METHODS: The cytotoxicity of the aqueous and methanol extracts and fractions of both species was studied using the brine shrimp lethality tests (BST) for the first time. RESULTS: The results demonstrated that the lethality (LC50) for crude extracts for both plants ranged between 1.8 and 5.8 ppm and was relatively greater than that for the methanol, ethyl acetate and chloroform fractions of the extracts which ranged between 2.1 ppm and 27 ppm. This suggested that crude extracts were more potent than their respective fractions, further explaining that the different fractions of phytochemicals in these plant species work jointly (in synergy) to exert their therapeutic efficacy. Both aqueous and methanol extracts of the two medicinal plants demonstrated a high degree of antioxidant capacity against the DPPH radical with the Duh and Yen inhibition percentage ranging between 4.5% and 72%. Phytochemical studies of the rhizome extracts showed that the major compounds present include flavonoids, tannins, anthocyanidins, anthraquinones, triterpenoids (oleanolic acid), the steroidal saponin Diosgenin, the sugars, rhamnose, glucuronic acid, Arabinose and hexoses. CONCLUSION: This is the first report of the detection and isolation of diosgenin and oleanolic acid from the rhizome extracts of Ee and Pp. All structures were determined using spectroscopic/spectrometric techniques (1H NMR and 13C and LC-ESI-MS) and by comparison with literature data.

Determination of catechins from Elephantorrhiza elephantina and Pentanisia prunelloides using voltammetry and UV spectroscopy.

In this work, we report the identification and quantification of catechins by electrochemistry and UV-Vis spectroscopy in Elephantorrhiza elephantina (Fabaceae) and Pentanisia prunelloides (Rubiaceae), both of which are medicinal plants that are widely used in Southern Africa to remedy various ailments. A comparative study of the catechin content as (-)-epicatechin equivalent is reported for the first time, with E. elephantina exhibiting a higher concentration relative to P. prunelloides in both aqueous and methanol extracts.

Should warfarin or aspirin be stopped prior to prostate biopsy? An analysis of bleeding complications related to increasing sample number regimes.

AIM: To determine whether patients undergoing transrectal ultrasound (TRUS)-guided prostate biopsy with increased sampling numbers are more likely to experience bleeding complications and whether warfarin or low-dose aspirin are independent risk factors. MATERIALS AND METHODS: 930 consecutive patients with suspected prostatic cancer were followed up after biopsy. Warfarin/low-dose aspirin was not stopped prior to the procedure. An eight to 10 sample regime TRUS-guided prostate biopsy was performed and patients were offered a questionnaire to complete 10 days after the procedure, to determine any immediate or delayed bleeding complications. RESULTS: 902 patients returned completed questionnaires. 579 (64.2%) underwent eight core biopsies, 47 (5.2%) underwent nine, and 276 (30.6%) underwent 10. 68 were taking warfarin [mean international normalized ratio (INR) = 2.5], 216 were taking low-dose aspirin, one was taking both, and 617 were taking neither. 27.9% of those on warfarin and 33.8% of those on aspirin experienced haematuria. 37% of those on no blood-thinning medication experienced haematuria. 13.2% of those on warfarin and 14.4% of those on aspirin experienced rectal bleeding. 11.5% of those on no blood-thinning medication experienced rectal bleeding. 7.4% of those on warfarin and 12% of those on aspirin experienced haematospermia. 13.8% of those on neither experienced haematospermia. Regression analysis showed a significant association between increasing sampling number and occurrence of all bleeding complication types. There was no significant association between minor bleeding complications and warfarin use; however, there was a significant association between minor bleeding complications and low-dose aspirin use. There was no severe bleeding complication. CONCLUSION: There is an increased risk of bleeding complications following TRUS-guided prostate biopsy with increased sampling numbers but these are minor. There is also an increased risk with low-dose aspirin use; however, there is no increased risk of bleeding complications with warfarin use. These results suggest that up to 10 cores during prostate biopsy remains acceptable safe practice and cessation of warfarin and low-dose aspirin is usually not necessary.

Ultrasound findings of masses of the paratesticular space.

Ultrasound is a routine investigation for the assessment of scrotal masses. Many of the detected lesions involve the paratesticular structures. The most common paratesticular masses in clinical practice are epididymal cysts and spermatoceles, but there are a large number of other pathologies that can be encountered and may result in diagnostic uncertainty. This review covers a wide range of the common and the rare, but important, causes of paratesticular masses. The ultrasound findings (both typical and atypical) of these lesions are clarified, and emphasis is given to the features that help to differentiate between them.

Late relapse of metastatic non-seminomatous testicular germ cell tumours.

Although the majority of men presenting with non-seminomatous germ cell tumours (NSGCT) are cured, late relapse (occurring more than 2 years after obtaining a complete response to treatment) is increasingly recognized. The typical patterns of disease spread have been well-documented, but the findings at late relapse are more variable and less well-described. We discuss the phenomenon of late relapse, the characteristics of teratoma differentiated (TD), and the issue of long-term imaging surveillance of patients with NSGCT. The potential sites of late relapse of NSGCT and the associated spectrum of imaging appearances are illustrated.