Hepatitis C virus among genitourinary clinic attenders in Scotland: unlinked anonymous testing

Our objective is to gauge the prevalence of hepatitis C virus (HCV) antibodies among a population at risk of contracting sexually transmitted infections (STIs) and, thus, the efficiency with which the virus is transmitted sexually. The investigators undertook an unlinked anonymous HCV antibody testing study of residual syphilis serology specimens taken from attenders of genitourinary clinics in Glasgow, Edinburgh and Aberdeen during 1996/97. The results were linked to non-identifying risk information. Anti-HCV prevalences among non-injecting heterosexual men and women, and non-injecting homosexual/bisexual males ranged between 0 and 1.2%; the only exception to this was a 7.7% (4/52) prevalence among homosexual/bisexual males in Aberdeen. The overall anti-HCV prevalence for homosexual/bisexual males was 0.6% (4/668), for heterosexual males 0.8% (32/4135), for heterosexual females 0.3% (10/3035) and for injecting drug users 49% (72/148). Only 3 (all female) of the 46 non-injectors who were antibody positive were non-UK nationals or had lived abroad. HCV antibody positive injectors were less likely to have an acute STI and more likely to know their HCV status than non-injectors; no differences in these parameters were found between positive and negative non-injectors on anonymous HCV antibody testing. Our findings are in keeping with the prevailing view that HCV can be acquired through sexual intercourse but, for most people, the probability of this occurring is extremely low. Interventions to prevent the spread of HCV should be targeted mainly at injecting drug user (IDU) populations.

The Dentin Matrix Protein 1 (Dmp1) is Specifically Expressed in Mineralized, but not Soft, Tissues during Development

Dentin Matrix Protein 1 ( Dmp1) was originally identified from dentin. However, its expression and function in vivo are not clear. To clarify these two issues, we have generated mice carrying a truncated Dmp1 gene by using gene targeting to replace exon 6 with a lacZ gene. Northern blot analysis shows the expected 5.8-kb Dmp1-lacZ fusion transcript and loss of the wild-type 2.8-kb Dmp1 transcript, confirmed by a lack of immunostaining for the protein. Using heterozygous animals, we demonstrate that Dmp1 is specific for mineralized tissues. Not previously shown, Dmp1 is also expressed in pulp cells. Dmp1-deficient embryos and newborns display no apparent gross abnormal phenotype, although there are a modest expansion of the hypertrophic chondrocyte zone and a modest increase in the long bone diameter. This suggests that DMP1 is not essential for early mouse skeletal or dental development.

Translocator positron-emission tomography and magnetic resonance spectroscopic imaging of brain glial cell activation in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is characterised by a diffuse inflammatory response mediated by microglia and astrocytes. Brain translocator protein (TSPO) positron-emission tomography (PET) and [myo-inositol] magnetic resonance spectroscopy (MRS) were used together to assess this.

OBJECTIVE

To explore the in vivo relationships between MRS and PET [¹¹C]PBR28 in MS over a range of brain inflammatory burden.

METHODS

A total of 23 patients were studied. TSPO PET imaging with [¹¹C]PBR28, single voxel MRS and conventional magnetic resonance imaging (MRI) sequences were undertaken. Disability was assessed by Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Functional Composite (MSFC).

RESULTS

[¹¹C]PBR28 uptake and [ myo-inositol] were not associated. When the whole cohort was stratified by higher [¹¹C]PBR28 inflammatory burden, [ myo-inositol] was positively correlated to [¹¹C]PBR28 uptake (Spearman's ρ = 0.685, p = 0.014). Moderate correlations were found between [¹¹C]PBR28 uptake and both MRS creatine normalised N-acetyl aspartate (NAA) concentration and grey matter volume. MSFC was correlated with grey matter volume (ρ = 0.535, p = 0.009). There were no associations between other imaging or clinical measures.

CONCLUSION

MRS [ myo-inositol] and PET [¹¹C]PBR28 measure independent inflammatory processes which may be more commonly found together with more severe inflammatory disease. Microglial activation measured by [¹¹C]PBR28 uptake was associated with loss of neuronal integrity and grey matter atrophy.

Disconnection between the default mode network and medial temporal lobes in post-traumatic amnesia

See Bigler (doi:10.1093/aww277) for a scientific commentary on this article.

Post-traumatic amnesia is very common immediately after traumatic brain injury. It is characterized by a confused, agitated state and a pronounced inability to encode new memories and sustain attention. Clinically, post-traumatic amnesia is an important predictor of functional outcome. However, despite its prevalence and functional importance, the pathophysiology of post-traumatic amnesia is not understood. Memory processing relies on limbic structures such as the hippocampus, parahippocampus and parts of the cingulate cortex. These structures are connected within an intrinsic connectivity network, the default mode network. Interactions within the default mode network can be assessed using resting state functional magnetic resonance imaging, which can be acquired in confused patients unable to perform tasks in the scanner. Here we used this approach to test the hypothesis that the mnemonic symptoms of post-traumatic amnesia are caused by functional disconnection within the default mode network. We assessed whether the hippocampus and parahippocampus showed evidence of transient disconnection from cortical brain regions involved in memory processing. Nineteen patients with traumatic brain injury were classified into post-traumatic amnesia and traumatic brain injury control groups, based on their performance on a paired associates learning task. Cognitive function was also assessed with a detailed neuropsychological test battery. Functional interactions between brain regions were investigated using resting-state functional magnetic resonance imaging. Together with impairments in associative memory, patients in post-traumatic amnesia demonstrated impairments in information processing speed and spatial working memory. Patients in post-traumatic amnesia showed abnormal functional connectivity between the parahippocampal gyrus and posterior cingulate cortex. The strength of this functional connection correlated with both associative memory and information processing speed and normalized when these functions improved. We have previously shown abnormally high posterior cingulate cortex connectivity in the chronic phase after traumatic brain injury, and this abnormality was also observed in patients with post-traumatic amnesia. Patients with post-traumatic amnesia showed evidence of widespread traumatic axonal injury measured using diffusion magnetic resonance imaging. This change was more marked within the cingulum bundle, the tract connecting the parahippocampal gyrus to the posterior cingulate cortex. These findings provide novel insights into the pathophysiology of post-traumatic amnesia and evidence that memory impairment acutely after traumatic brain injury results from altered parahippocampal functional connectivity, perhaps secondary to the effects of axonal injury on white matter tracts connecting limbic structures involved in memory processing.

Prevalence and correlates of vitamin D deficiency in adults after traumatic brain injury

OBJECTIVES

Traumatic brain injury (TBI) is a major cause of long-term disability with variable recovery. Preclinical studies suggest that vitamin D status influences the recovery after TBI. However, there is no published clinical data on links between vitamin D status and TBI outcomes. The aim was to determine the (i) prevalence of vitamin D deficiency/insufficiency, and associations of vitamin D status with (ii) demographic factors and TBI severity, and with (iii) cognitive function, symptoms and quality of life, in adults after TBI.

DESIGN

Retrospective audit of patients seen between July 2009 and March 2015. Serum vitamin D (25-hydroxy-cholecalciferol) was categorized as deficient (<40 nmol/l), insufficient (40-70 nmol/l) or replete (>70 nmol/l).

PATIENTS

A total of 353 adults seen in tertiary hospital clinic (75·4% lighter skinned, 74·8% male, age median 35·1 year, range 26·6-48·3 year), 0·3-56·5 months after TBI (74·5% moderate-severe).

MEASUREMENTS

Serum vitamin D concentrations; Addenbrooke's Cognitive Examination (ACE-R), Beck Depression Inventory-II (BDI-II), SF-36 Quality of Life, Pittsburgh Sleep Quality Index.

RESULTS

In total, 46·5% of patients after TBI had vitamin D deficiency and 80·2% insufficiency/deficiency. Patients with vitamin D deficiency had lower ACE-R scores than those of vitamin D replete (mean effect size ± SEM 4·5 ± 2·1, P = 0·034), and higher BDI-II scores than those of vitamin D insufficient (4·5 ± 1·6, P = 0·003), correcting for age, gender, time since TBI and TBI severity. There was no association between vitamin D status and markers of TBI severity, sleep or quality of life.

CONCLUSION

Vitamin D deficiency is common in patients after TBI and associated with impaired cognitive function and more severe depressive symptoms.

UKCC staff set for showdown with ralph

The management dispute at nursing's regulatory body is expected to enter its final phase later this week, with eight senior staff set to issue an official grievance against Registrar Colin Ralph.

Cortical Entropy, Mutual Information and Scale-Free Dynamics in Waking Mice

Some neural circuits operate with simple dynamics characterized by one or a few well-defined spatiotemporal scales (e.g. central pattern generators). In contrast, cortical neuronal networks often exhibit richer activity patterns in which all spatiotemporal scales are represented. Such “scale-free” cortical dynamics manifest as cascades of activity with cascade sizes that are distributed according to a power-law. Theory and in vitro experiments suggest that information transmission among cortical circuits is optimized by scale-free dynamics. In vivo tests of this hypothesis have been limited by experimental techniques with insufficient spatial coverage and resolution, i.e., restricted access to a wide range of scales. We overcame these limitations by using genetically encoded voltage imaging to track neural activity in layer 2/3 pyramidal cells across the cortex in mice. As mice recovered from anesthesia, we observed three changes: (a) cortical information capacity increased, (b) information transmission among cortical regions increased and (c) neural activity became scale-free. Our results demonstrate that both information capacity and information transmission are maximized in the awake state in cortical regions with scale-free network dynamics.

Kinetic analysis of the translocator protein positron emission tomography ligand [18F]GE-180 in the human brain

Purpose

PET can image neuroinflammation by targeting the translocator protein (TSPO), which is upregulated in activated microglia. The high nonspecific binding of the first-generation TSPO radioligand [¹¹C]PK-11195 limits accurate quantification. [¹⁸F]GE-180, a novel TSPO ligand, displays superior binding to [¹¹C]PK-11195 in vitro. Our objectives were to: (1) evaluate tracer characteristics of [¹⁸F]GE-180 in the brains of healthy human subjects; and (2) investigate whether the TSPO Ala147Thr polymorphism influences outcome measures.

Methods

Ten volunteers (five high-affinity binders, HABs, and five mixed-affinity binders, MABs) underwent a dynamic PET scan with arterial sampling after injection of [¹⁸F]GE-180. Kinetic modelling of time–activity curves with one-tissue and two-tissue compartment models and Logan graphical analysis was applied to the data. The primary outcome measure was the total volume of distribution (V_T) across various regions of interest (ROIs). Secondary outcome measures were the standardized uptake values (SUV), the distribution volume and SUV ratios estimated using a pseudoreference region.

Results

The two-tissue compartment model was the best model. The average regional delivery rate constant (K₁) was 0.01 mL cm⁻³ min⁻¹ indicating low extraction across the blood–brain barrier (1 %). The estimated median V_T across all ROIs was also low, ranging from 0.16 mL cm⁻³ in the striatum to 0.38 mL cm⁻³ in the thalamus. There were no significant differences in V_T between HABs and MABs across all ROIs.

Conclusion

A reversible two-tissue compartment model fitted the data well and determined that the tracer has a low first-pass extraction (approximately 1 %) and low V_T estimates in healthy individuals. There was no observable dependency on the rs6971 polymorphism as compared to other second-generation TSPO PET tracers. Investigation of [¹⁸F]GE-180 in populations with neuroinflammatory disease is needed to determine its suitability for quantitative assessment of TSPO expression.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-016-3444-z) contains supplementary material, which is available to authorized users.

Comparison of time to undetectable HIV viral load in the first 16 weeks after the start of three and four antiretroviral regimens

The aim of this paper is to compare the time to a viral load <50 copies/mL of three or four antiretroviral therapy (ART) regimens among ART naïve patients within the first 16 weeks after the start of treatment. A retrospective study was carried out on ART naïve patients who started HAART between 1 January 1999 and 1 January 2004. ART naïve patients with a viral load >5.3 log10 copies/mL at the time of treatment were routinely started on four ART regimens in one of the HIV centres in Edinburgh. These patients were compared with ART naïve patients with viral load >5.3 log10 copies/mL at the time of start of three ART regimens in the other centre within the study period. During the study period, of 93 ART naïve patients with a viral load >5.3 log10 copies/mL, 56 and 37 commenced four drug and three drug regimens, respectively. Patients in each group were matched for their age, prevalence of HCV, median age, and median viral load at the start of therapy; however, patients on three drug regimens had significantly lower CD4 counts ( P<0.01). The median time to undetectable viral load was 13.5 weeks for three and four drug regimens ( P>0.05). By the time of undetectable viral load, there was no difference in the CD4 count of patients on three or four drug regimens. Similar proportions of immunosuppressed patients on three and four ART regimens had undetectable viral load within the first 16 weeks of therapy.

Heterosexual men and women with HIV test positive at a later stage of infection than homo- or bisexual men

The current strategy of offering HIV testing to individuals with known risk has had no impact on the reduction in the number of patients diagnosed with immune suppression of infection. A prospective observational study to compare the baseline CD4+ T-cell counts in HIV-infected homosexual/bisexual men, intravenous drug users, heterosexual men and women diagnosed in GUM/RIDU and that of patients diagnosed during routine maternal screening for HIV between December 1999 and January 2003 was carried out at the Departments of Genitourinary Medicine (GUM), Regional Infectious Disease Unit (RIDU) and Obstetrics in Edinburgh.

Late presentation was defined as positive HIV test with baseline CD4+ T-cell count of less than 200 cells/mL.

During the study period, 189 patients tested in GUM/RIDU setting and 13 screened women were diagnosed with HIV infection. Thirty-four percent of the former and 38% of the latter group had CD4+ T-cell count of less than 200 cells/mL by the time of diagnosis. Heterosexual individuals contributed to 78% of HIV tests in the GUM/RIDU setting. Amongst the 78 HIV-infected heterosexual individuals diagnosed in GUM/RIDU 45% were late presenters. Significantly fewer homosexual men were late presenters. There was no difference between the proportion of late presenters amongst women screened at the antenatal (5/13) compared to heterosexual patients diagnosed in GUM/RIDU (35/78). A significant number of HIV infected heterosexual patients are late presenters in the HIV testing at GUM/RIDU. HIV screening programmes for heterosexual individuals in any medical encounter may reduce the number of late presenters.

Novel Modeling of Task vs. Rest Brain State Predictability Using a Dynamic Time Warping Spectrum: Comparisons and Contrasts with Other Standard Measures of Brain Dynamics

Dynamic time warping, or DTW, is a powerful and domain-general sequence alignment method for computing a similarity measure. Such dynamic programming-based techniques like DTW are now the backbone and driver of most bioinformatics methods and discoveries. In neuroscience it has had far less use, though this has begun to change. We wanted to explore new ways of applying DTW, not simply as a measure with which to cluster or compare similarity between features but in a conceptually different way. We have used DTW to provide a more interpretable spectral description of the data, compared to standard approaches such as the Fourier and related transforms. The DTW approach and standard discrete Fourier transform (DFT) are assessed against benchmark measures of neural dynamics. These include EEG microstates, EEG avalanches, and the sum squared error (SSE) from a multilayer perceptron (MLP) prediction of the EEG time series, and simultaneously acquired FMRI BOLD signal. We explored the relationships between these variables of interest in an EEG-FMRI dataset acquired during a standard cognitive task, which allowed us to explore how DTW differentially performs in different task settings. We found that despite strong correlations between DTW and DFT-spectra, DTW was a better predictor for almost every measure of brain dynamics. Using these DTW measures, we show that predictability is almost always higher in task than in rest states, which is consistent to other theoretical and empirical findings, providing additional evidence for the utility of the DTW approach.

Surgical management of maxillary and premaxillary osteomyelitis in a reticulated python (Python reticulatus)

CASE DESCRIPTION A 1-year-old reticulated python (Python reticulatus) was evaluated because of a 2-week history of wheezing and hissing. CLINICAL FINDINGS Rostral facial cellulitis and deep gingival pockets associated with missing rostral maxillary teeth were evident. Tissues of the nares were swollen, resulting in an audible wheeze during respiration. Multiple scars and superficial facial wounds attributed to biting by live prey were apparent. Radiographic examination revealed bilateral, focal, rostral maxillary osteomyelitis. TREATMENT AND OUTCOME Wound irrigation, antimicrobials, and anti-inflammatory drug treatment resulted in reduced cellulitis. A 3-week regimen that included empirical antimicrobial treatment and improved husbandry resulted in resolution of the respiratory sounds and partial healing of bite wounds, but radiographic evaluation revealed progressive maxillary osteomyelitis. Microbial culture of blood yielded scant gram-positive cocci and Bacillus spp, which were suspected sample contaminants. Bilateral partial maxillectomies were performed; microbial culture and histologic examination of resected bone confirmed osteomyelitis with gram-positive cocci. Treatment with trimethoprim-sulfamethoxazole was initiated on the basis of microbial susceptibility tests. Four months later, follow-up radiography revealed premaxillary osteomyelitis; surgery was declined, and treatment with trimethoprim-sulfamethoxazole was reinstituted. Eight months after surgery, the patient was reevaluated because of recurrent clinical signs; premaxillectomy was performed, and treatment with trimethoprim-sulfamethoxazole was prescribed on the basis of microbial culture of bone and microbial susceptibility testing. Resolution of osteomyelitis was confirmed by CT 11 months after the initial surgery. CONCLUSIONS AND CLINICAL RELEVANCE Focal maxillectomies and premaxillectomy were successfully performed in a large python. Surgical management and appropriate antimicrobial treatment resulted in a good outcome.

Can a total knee arthroplasty be both rotationally unconstrained and anteroposteriorly stabilised? A pulsed fluoroscopic investigation

OBJECTIVES

Throughout the 20th Century, it has been postulated that the knee moves on the basis of a four-bar link mechanism composed of the cruciate ligaments, the femur and the tibia. As a consequence, the femur has been thought to roll back with flexion, and total knee arthroplasty (TKA) prostheses have been designed on this basis. Recent work, however, has proposed that at a position of between 0° and 120° the medial femoral condyle does not move anteroposteriorly whereas the lateral femoral condyle tends, but is not obliged, to roll back - a combination of movements which equates to tibial internal/ femoral external rotation with flexion. The aim of this paper was to assess if the articular geometry of the GMK Sphere TKA could recreate the natural knee movements in situ/in vivo.

METHODS

The pattern of knee movement was studied in 15 patients (six male: nine female; one male with bilateral TKAs) with 16 GMK Sphere implants, at a mean age of 66 years (53 to 76) with a mean BMI of 30 kg/m(2) (20 to 35). The motions of all 16 knees were observed using pulsed fluoroscopy during a number of weight-bearing and non-weight-bearing static and dynamic activities.

RESULTS

During maximally flexed kneeling and lunging activities, the mean tibial internal rotation was 8° (standard deviation (sd) 6). At a mean 112° flexion (sd 16) during lunging, the medial and lateral condyles were a mean of 2 mm (sd 3) and 8 mm (sd 4) posterior to a transverse line passing through the centre of the medial tibial concavity. With a mean flexion of 117° (sd 14) during kneeling, the medial and lateral condyles were a mean of 1 mm (sd 4) anterior and 6 mm (sd 4) posterior to the same line. During dynamic stair and pivoting activities, there was a mean anteroposterior translation of 0 mm to 2 mm of the medial femoral condyle. Backward lateral condylar translation occurred and was linearly related to tibial rotation.

CONCLUSION

The GMK Sphere TKA in our study group shows movements similar in pattern, although reduced in magnitude, to those in recent reports relating to normal knees during several activities. Specifically, little or no translation of the medial femoral condyle was observed during flexion, but there was posterior roll-back of the lateral femoral condyle, equating to tibiofemoral rotation. We conclude that the GMK Sphere is anteroposteriorly stable medially and permits rotation about the medial compartment.Cite this article: Professor G. Scott. Can a total knee arthroplasty be both rotationally unconstrained and anteroposteriorly stabilised?: A pulsed fluoroscopic investigation. Bone Joint Res 2016;5:80-86. DOI: 10.1302/2046-3758.53.2000621.

Amyloid pathology and axonal injury after brain trauma

OBJECTIVE

To image β-amyloid (Aβ) plaque burden in long-term survivors of traumatic brain injury (TBI), test whether traumatic axonal injury and Aβ are correlated, and compare the spatial distribution of Aβ to Alzheimer disease (AD).

METHODS

Patients 11 months to 17 years after moderate-severe TBI underwent (11)C-Pittsburgh compound B ((11)C-PiB)-PET, structural and diffusion MRI, and neuropsychological examination. Healthy aged controls and patients with AD underwent PET and structural MRI. Binding potential (BPND) images of (11)C-PiB, which index Aβ plaque density, were computed using an automatic reference region extraction procedure. Voxelwise and regional differences in BPND were assessed. In TBI, a measure of white matter integrity, fractional anisotropy, was estimated and correlated with (11)C-PiB BPND.

RESULTS

Twenty-eight participants (9 with TBI, 9 controls, 10 with AD) were assessed. Increased (11)C-PiB BPND was found in TBI vs controls in the posterior cingulate cortex and cerebellum. Binding in the posterior cingulate cortex increased with decreasing fractional anisotropy of associated white matter tracts and increased with time since injury. Compared to AD, binding after TBI was lower in neocortical regions but increased in the cerebellum.

CONCLUSIONS

Increased Aβ burden was observed in TBI. The distribution overlaps with, but is distinct from, that of AD. This suggests a mechanistic link between TBI and the development of neuropathologic features of dementia, which may relate to axonal damage produced by the injury.

The effect of oppositional parietal transcranial direct current stimulation on lateralized brain functions

Cognitive functions such as numerical processing and spatial attention show varying degrees of lateralization. Transcranial direct current stimulation (tDCS) can be used to investigate how modulating cortical excitability affects performance of these tasks. This study investigated the effect of bi-parietal tDCS on numerical processing, spatial and sustained attention. It was hypothesized that tDCS would have distinct effects on these tasks because of varying lateralization (numerical processing left, spatial attention right) and that these effects are partly mediated by modulation of sustained attention. A single-blinded, crossover, sham-controlled study was performed. Eighteen healthy right-handed participants performed cognitive tasks during three sessions of oppositional parietal tDCS stimulation: sham; right anodal with left cathodal (RA/LC); and right cathodal with left anodal (RC/LA). Participants performed a number comparison task, a modified Posner task, a choice reaction task (CRT) and the rapid visual processing task (RVP). RA/LC tDCS impaired number comparison performance compared with sham, with slower responses to numerically close numbers pairs. RA/LC and RC/LA tDCS had distinct effects on CRT performance, specifically affecting vigilance level during the final block of the task. No effect of stimulation on the Posner task or RVP was found. It was demonstrated that oppositional parietal tDCS affected both numerical performance and vigilance level in a polarity-dependent manner. The effect of tDCS on numerical processing may partly be due to attentional effects. The behavioural effects of tDCS were specifically observed under high task demands, demonstrating the consequences of an interaction between stimulation type and cognitive load.

Thalamic inflammation after brain trauma is associated with thalamo-cortical white matter damage

Background

Traumatic brain injury can trigger chronic neuroinflammation, which may predispose to neurodegeneration. Animal models and human pathological studies demonstrate persistent inflammation in the thalamus associated with axonal injury, but this relationship has never been shown in vivo.

Findings

Using [¹¹C]-PK11195 positron emission tomography, a marker of microglial activation, we previously demonstrated thalamic inflammation up to 17 years after traumatic brain injury. Here, we use diffusion MRI to estimate axonal injury and show that thalamic inflammation is correlated with thalamo-cortical tract damage.

Conclusions

These findings support a link between axonal damage and persistent inflammation after brain injury.

Effects of lesions on synchrony and metastability in cortical networks

At the macroscopic scale, the human brain can be described as a complex network of white matter tracts integrating grey matter assemblies - the human connectome. The structure of the connectome, which is often described using graph theoretic approaches, can be used to model macroscopic brain function at low computational cost. Here, we use the Kuramoto model of coupled oscillators with time-delays, calibrated with respect to empirical functional MRI data, to study the relation between the structure of the connectome and two aspects of functional brain dynamics - synchrony, a measure of general coherence, and metastability, a measure of dynamical flexibility. Specifically, we investigate the relationship between the local structure of the connectome, quantified using graph theory, and the synchrony and metastability of the model's dynamics. By removing individual nodes and all of their connections from the model, we study the effect of lesions on both global and local dynamics. Of the nine nodal graph-theoretical properties tested, two were able to predict effects of node lesion on the global dynamics. The removal of nodes with high eigenvector centrality leads to decreases in global synchrony and increases in global metastability, as does the removal of hub nodes joining topologically segregated network modules. At the level of local dynamics in the neighbourhood of the lesioned node, structural properties of the lesioned nodes hold more predictive power, as five nodal graph theoretical measures are related to changes in local dynamics following node lesions. We discuss these results in the context of empirical studies of stroke and functional brain dynamics.

Physiologically Based Models in Regulatory Submissions: Output From the ABPI/MHRA Forum on Physiologically Based Modeling and Simulation

Under the remit of the Ministerial Industry Strategy Group (MISG), the Association of the British Pharmaceutical Industry (ABPI) and Medicines and Healthcare products Regulatory Agency (MHRA) hosted a meeting to explore physiologically based pharmacokinetic modeling and simulation, focusing on the clinical component of regulatory applications. The meeting took place on 30 June 2014 with international representatives from industry, academia, and regulatory agencies. Discussion topics were selected to be complementary to those discussed at an earlier US Food and Drug Administration (FDA) meeting. This report summarizes the meeting outcomes, focusing on the European regulatory perspective.

Disconnection of network hubs and cognitive impairment after traumatic brain injury

Traumatic brain injury (TBI) affects brain connectivity, which disrupts the large-scale networks that support cognitive function. Fagerholm et al. use graph analysis, with brain regions as nodes and white matter tracts as connections, to show that TBI particularly disrupts the connectivity of hubs, and that this disconnection predicts cognitive impairment.

Traumatic brain injury affects brain connectivity by producing traumatic axonal injury. This disrupts the function of large-scale networks that support cognition. The best way to describe this relationship is unclear, but one elegant approach is to view networks as graphs. Brain regions become nodes in the graph, and white matter tracts the connections. The overall effect of an injury can then be estimated by calculating graph metrics of network structure and function. Here we test which graph metrics best predict the presence of traumatic axonal injury, as well as which are most highly associated with cognitive impairment. A comprehensive range of graph metrics was calculated from structural connectivity measures for 52 patients with traumatic brain injury, 21 of whom had microbleed evidence of traumatic axonal injury, and 25 age-matched controls. White matter connections between 165 grey matter brain regions were defined using tractography, and structural connectivity matrices calculated from skeletonized diffusion tensor imaging data. This technique estimates injury at the centre of tract, but is insensitive to damage at tract edges. Graph metrics were calculated from the resulting connectivity matrices and machine-learning techniques used to select the metrics that best predicted the presence of traumatic brain injury. In addition, we used regularization and variable selection via the elastic net to predict patient behaviour on tests of information processing speed, executive function and associative memory. Support vector machines trained with graph metrics of white matter connectivity matrices from the microbleed group were able to identify patients with a history of traumatic brain injury with 93.4% accuracy, a result robust to different ways of sampling the data. Graph metrics were significantly associated with cognitive performance: information processing speed (R² = 0.64), executive function (R² = 0.56) and associative memory (R² = 0.25). These results were then replicated in a separate group of patients without microbleeds. The most influential graph metrics were betweenness centrality and eigenvector centrality, which provide measures of the extent to which a given brain region connects other regions in the network. Reductions in betweenness centrality and eigenvector centrality were particularly evident within hub regions including the cingulate cortex and caudate. Our results demonstrate that betweenness centrality and eigenvector centrality are reduced within network hubs, due to the impact of traumatic axonal injury on network connections. The dominance of betweenness centrality and eigenvector centrality suggests that cognitive impairment after traumatic brain injury results from the disconnection of network hubs by traumatic axonal injury.

Systems Medicine 2.0: potential benefits of combining electronic health care records with systems science models

Background

The global burden of disease is increasingly dominated by non-communicable diseases.These diseases are less amenable to curative and preventative interventions than communicable disease. This presents a challenge to medical practice and medical research, both of which are experiencing diminishing returns from increasing investment.

Objective

Our aim was to (1) review how medical knowledge is generated, and its limitations, (2) assess the potential for emerging technologies and ideas to improve medical research, and (3) suggest solutions and recommendations to increase medical research efficiency on non-communicable diseases.

Methods

We undertook an unsystematic review of peer-reviewed literature and technology websites.

Results

Our review generated the following conclusions and recommendations. (1) Medical knowledge continues to be generated in a reductionist paradigm. This oversimplifies our models of disease, rendering them ineffective to sufficiently understand the complex nature of non-communicable diseases. (2) Some of these failings may be overcome by adopting a “Systems Medicine” paradigm, where the human body is modeled as a complex adaptive system. That is, a system with multiple components and levels interacting in complex ways, wherein disease emerges from slow changes to the system set-up. Pursuing systems medicine research will require larger datasets. (3) Increased data sharing between researchers, patients, and clinicians could provide this unmet need for data. The recent emergence of electronic health care records (EHR) could potentially facilitate this in real-time and at a global level. (4) Efforts should continue to aggregate anonymous EHR data into large interoperable data silos and release this to researchers. However, international collaboration, data linkage, and obtaining additional information from patients will remain challenging. (5) Efforts should also continue towards “Medicine 2.0”. Patients should be given access to their personal EHR data. Subsequently, online communities can give researchers the opportunity to ask patients for direct access to the patient’s EHR data and request additional study-specific information. However, selection bias towards patients who use Web 2.0 technology may be difficult to overcome.

Conclusions

Systems medicine, when combined with large-scale data sharing, has the potential to raise our understanding of non-communicable diseases, foster personalized medicine, and make substantial progress towards halting, curing, and preventing non-communicable diseases. Large-scale data amalgamation remains a core challenge and needs to be supported. A synthesis of “Medicine 2.0” and “Systems Science” concepts into “Systems Medicine 2.0” could take decades to materialize but holds much promise.

Exploring spatiotemporal network transitions in task functional MRI

A critical question for cognitive neuroscience regards how transitions between cognitive states emerge from the dynamic activity of functional brain networks. Here we combine a simple data reorganization with spatial independent component analysis (ICA), enabling a spatiotemporal ICA (stICA) which captures the consistent evolution of networks during the onset and offset of a task. The technique was applied to functional magnetic resonance imaging (MRI) (FMRI) datasets involving alternating between rest and task, and to simple synthetic data. Starting and finishing time-points of periods of interest (anchors) were defined at task block onsets and offsets. For each subject, the 10 volumes following each anchor were extracted and concatenated spatially, producing a single 3D sample. Samples for all anchors and subjects were concatenated along the fourth dimension. This 4D dataset was decomposed using ICA into spatiotemporal components. One component exhibited the transition with task onset from a default mode network (DMN) becoming less active to a frontoparietal control network becoming more active. We observed other changes with relevance to understanding network dynamics, for example, the DMN showed a changing spatial distribution, shifting to an anterior/superior pattern of deactivation during task from a posterior/inferior pattern during rest. By anchoring analyses to periods associated with the onsets and offsets of task, our approach reveals novel aspects of the dynamics of network activity accompanying these transitions. Importantly, these findings were observed without specifying a priori either the spatial networks or the task time courses.

Single-stage revision for the infected total knee replacement: results from a single centre

Peri-prosthetic infection is amongst the most common causes of failure following total knee replacement (TKR). In the presence of established infection, thorough joint debridement and removal of all components is necessary following which new components may be implanted. This can be performed in one or two stages; two-stage revision with placement of an interim antibiotic-loaded spacer is regarded by many to be the standard procedure for eradication of peri-prosthetic joint infection. We present our experience of a consecutive series of 50 single-stage revision TKRs for established deep infection performed between 1979 and 2010. There were 33 women and 17 men with a mean age at revision of 66.8 years (42 to 84) and a mean follow-up of 10.5 years (2 to 24). The mean time between the primary TKR and the revision procedure was 2.05 years (1 to 8). Only one patient required a further revision for recurrent infection, representing a success rate of 98%. Nine patients required further revision for aseptic loosening, according to microbiological testing of biopsies taken at the subsequent surgery. Three other patients developed a further septic episode but none required another revision. These results suggest that a single-stage revision can produce comparable results to a two-stage revision. Single-stage revision offers a reduction in costs as well as less morbidity and inconvenience for patients.

Spatial dependencies between large-scale brain networks

Functional neuroimaging reveals both increases (task-positive) and decreases (task-negative) in neural activation with many tasks. Many studies show a temporal relationship between task positive and task negative networks that is important for efficient cognitive functioning. Here we provide evidence for a spatial relationship between task positive and negative networks. There are strong spatial similarities between many reported task negative brain networks, termed the default mode network, which is typically assumed to be a spatially fixed network. However, this is not the case. The spatial structure of the DMN varies depending on what specific task is being performed. We test whether there is a fundamental spatial relationship between task positive and negative networks. Specifically, we hypothesize that the distance between task positive and negative voxels is consistent despite different spatial patterns of activation and deactivation evoked by different cognitive tasks. We show significantly reduced variability in the distance between within-condition task positive and task negative voxels than across-condition distances for four different sensory, motor and cognitive tasks - implying that deactivation patterns are spatially dependent on activation patterns (and vice versa), and that both are modulated by specific task demands. We also show a similar relationship between positively and negatively correlated networks from a third ‘rest’ dataset, in the absence of a specific task. We propose that this spatial relationship may be the macroscopic analogue of microscopic neuronal organization reported in sensory cortical systems, and that this organization may reflect homeostatic plasticity necessary for efficient brain function.

Out of sight, but not out of mind? Greater reported pain in patients who spontaneously look away during venepuncture

BACKGROUND

Various external factors can influence patients' experiences of noxious stimuli, but little is known of how patients' natural behaviour may be relevant. We ascertained how often patients spontaneously look or look away during venepuncture and associated reports of pain during a previously reported experimental randomized study. The study was conducted in the outpatient department of a U.K. district general hospital.

METHODS

Patients were randomized to hearing 'sharp scratch' or the verbal cue 'ready?' immediately before venepuncture. Whether patients looked or looked away during needle insertion was recorded. Patients were asked to rate their pain using a verbal numerical rating score (VNRS) and verbal response scale (VRS).

RESULTS

One hundred ninety-two patients were included; mean age 51.7 years, 55% male. During needle insertion, 73% spontaneously looked away, whereas 27% looked. There was no significant difference in the proportion of these patients assigned to the 'sharp scratch' or 'ready?' groups, nor was there any difference in mean age or gender. For the group that looked, mean VNRS was 0.48 and VRS was 1.27, significantly less than the group that looked away (mean VNRS 0.94, p = 0.014; VRS 1.61, p = 0.002). As previously reported, pain ratings between 'sharp scratch' and 'ready?' groups were not significantly different.

CONCLUSIONS

Almost three quarters of patients spontaneously look away during venepuncture, but their pain ratings are almost twice that of the quarter of patients who look. It is unclear why this may be, but previous experimental studies indicate that observing the body when a noxious stimulus is applied can have an analgesic effect.

Visual and proprioceptive interaction in patients with bilateral vestibular loss

Following bilateral vestibular loss (BVL) patients gradually adapt to the loss of vestibular input and rely more on other sensory inputs. Here we examine changes in the way proprioceptive and visual inputs interact. We used functional magnetic resonance imaging (fMRI) to investigate visual responses in the context of varying levels of proprioceptive input in 12 BVL subjects and 15 normal controls. A novel metal-free vibrator was developed to allow vibrotactile neck proprioceptive input to be delivered in the MRI system. A high level (100 Hz) and low level (30 Hz) control stimulus was applied over the left splenius capitis; only the high frequency stimulus generates a significant proprioceptive stimulus. The neck stimulus was applied in combination with static and moving (optokinetic) visual stimuli, in a factorial fMRI experimental design. We found that high level neck proprioceptive input had more cortical effect on brain activity in the BVL patients. This included a reduction in visual motion responses during high levels of proprioceptive input and differential activation in the midline cerebellum. In early visual cortical areas, the effect of high proprioceptive input was present for both visual conditions but in lateral visual areas, including V5/MT, the effect was only seen in the context of visual motion stimulation. The finding of a cortical visuo-proprioceptive interaction in BVL patients is consistent with behavioural data indicating that, in BVL patients, neck afferents partly replace vestibular input during the CNS-mediated compensatory process. An fMRI cervico-visual interaction may thus substitute the known visuo-vestibular interaction reported in normal subject fMRI studies. The results provide evidence for a cortical mechanism of adaptation to vestibular failure, in the form of an enhanced proprioceptive influence on visual processing. The results may provide the basis for a cortical mechanism involved in proprioceptive substitution of vestibular function in BVL patients.

•

A novel air turbine vibrotactile device for the MRI environment is developed.

•

Neck proprioception and visual motion are applied in a factorial fMRI experiment.

•

A cervico-visual fMRI interaction is shown in bilateral vestibular loss patients (BVL).

•

This cervico-visual interaction in BVL mimics the normal visuo-vestibular interaction.

Antifungal step-down therapy based on hospital intravenous to oral switch policy and susceptibility testing in adult patients with candidaemia: a single centre experience

AIMS

Echinocandins are recommended for the treatment of candidaemia in moderately severe to severely ill patients. Step-down or de-escalation from echinocandin to fluconazole is advised in patients who are clinically stable but data in relation to step-down therapy are sparse. Using our hospital intravenous to oral switch therapy (IVOST) policy to guide antifungal de-escalation in patients with candidaemia, we aimed to determine what proportion of patients are de-escalated to fluconazole, the timescale to step-down, associated reduction in consumption of echinocandins and antifungal cost savings.

METHODOLOGY

Patients with candidaemia were followed from April 2011 to March 2013.

RESULTS

A total of 37 episodes of candidaemia were documented during the study period. Twenty-seven patients were commenced on an echinocandin or voriconazole and 19 (70.3%) were de-escalated to fluconazole based on the IVOST policy. The mean and median number of days to de-escalation of therapy was 4.6 and 5 days, respectively. One patient whose therapy was de-escalated relapsed. The overall 30 day crude mortality was 37.1%. The step-down approach led to significant saving in antifungal drug cost of £1133.88 per candidaemic episode and £2208.08 per de-escalation.

CONCLUSION

Implementation of IVOST policy led to streamlining of antifungal therapy.

How sharp is a "sharp scratch"? A mixed methods study of verbal warnings issued before venipuncture

OBJECTIVES

Health care providers frequently issue a verbal warning before venipuncture. Communications that induce negative expectations in patients can lead to the "nocebo" response, defined as experiencing greater pain. But is this also true for "sharp scratch"?

METHODS

The study was conducted across 4 U.K. hospitals. Two separate surveys of health care providers and patients explored the prevalence, phraseology, rationale, and reaction to verbal warnings before venipuncture. Blinded adult patients already attending an outpatient department during a 2-week period were randomized to hearing a "sharp scratch" or the verbal cue "ready?" immediately before venipuncture. They were also asked to rate their pain (the primary outcome).

RESULTS

77% of 117 health care providers surveyed issued a verbal warning before venipuncture; 73% used "sharp scratch". Of 62 patients surveyed, 56% agreed that "sharp scratch" accurately describes venipuncture, and 64% agreed that they prefer "sharp scratch" to no warning. With increasing age, a preference came for an alternative warning to "sharp scratch" (P = 0.039) and to be distracted by conversation (P = 0.002). Of 192 patients in the randomized study, there was no difference in pain between the "sharp scratch" and "ready" groups. The numeric rating scores were 0.74 SD 1.06 vs. 0.88 SD 1.18, respectively. (P = 0.493).

CONCLUSIONS

Most health care providers use the verbal warning "sharp scratch" before venipuncture. Most patients find this acceptable and prefer it to no warning. An exception may be elderly patients, who may prefer to be distracted by conversation. "Sharp scratch" makes no difference to the pain experienced compared with a verbal cue.

A case of multicentric Castleman's disease in HIV infection with the rare complication of acquired angioedema

Multicentric Castleman's disease (MCD), a polyclonal lymphoproliferative disorder of unknown aetiology, is a well-recognised complication of HIV disease. We present a case of MCD in an HIV-positive patient that is unusual on two counts: our patient's MCD first presented in the context of an immune restoration inflammatory syndrome (IRIS), following the initiation of highly active antiretroviral therapy (HAART). In addition, her MCD was associated with the unusual complication of acquired angioedema (AAE), which resolved following treatment of the MCD. While AAE is frequently found to have an underlying diagnosis of a lymphoproliferative disease, this is the first reported case linking AAE to MCD.

Lung sounds: how doctors draw crackles and wheeze

BACKGROUND

The content of medical records is a potential source of miscommunication between clinicians. Doctors' written entries have been criticised for their illegibility and ambiguity, but no studies have examined doctors' drawings that are commonly used for recording auscultation findings.

OBJECTIVE

To compare doctors' drawings of auscultation findings, based on identical clinical information.

METHODS

Doctors at the Royal London Hospital and a group of London based general practitioners (GPs) documented a respiratory examination with a drawing of the auscultation findings of bilateral mid and lower zone wheeze and right lower zone crackles. The graphical properties of each drawing were examined and the use of written captions and labels recorded. Drawings were classified into styles according to the use of symbols (defined as discrete characters or icons) and shading (cross-hatching, speckling or darkening) to depict the auscultation findings. The study was conducted between September and November 2011.

RESULTS

Sixty-nine hospital doctors and 13 GPs participated. Ten drawing styles were identified from 78 completed drawings. Ten distinct symbols and a range of shading techniques were used. The most frequent style (21% of drawings) combined 'X' symbols representing crackles with musical notes for wheeze. There was inconsistency of representation across the drawings. Forty-seven (60%) drawings used an 'X' symbol exclusively to represent crackles, but six (8%) used 'X' only to represent wheeze, and 10 (13%) used 'X' to represent both findings. 91% of participants included captions or labels with their drawing.

CONCLUSIONS

There was wide variation in doctors' drawings of identical auscultation findings, and inconsistency in the meaning of symbols both between and within drawings. Doctors risk incorrectly interpreting each other's drawings when they are not effectively labelled. We recommend doctors consider using a written description instead, or draw different findings with distinct symbols or shading, labelling all findings clearly.

Cardiac responses to 24 hrs hyperoxia in Bmp2 and Bmp4 heterozygous mice

BACKGROUND

Hyperoxia or clinical oxygen (O2) therapy is known to result in increased oxidative burden. Therefore, understanding susceptibility to hyperoxia exposure is clinically important. Bone morphogenetic proteins (BMPs) 2 and 4 are involved in cardiac development and may influence responses to hyperoxia.

METHODS

Bmp2(+/)(-). Bmp4(+/)(-) and wild-type mice were exposed to hyperoxia (100% O2) for 24 hrs. Electrocardiograms (ECG) were recorded before and during exposure by radio-telemetry.

RESULTS

At baseline, a significantly higher low frequency (LF) and total power (TP) heart rate variability (HRV) were found in Bmp2(+/)(-) mice only (p < 0.05). Twenty-four hours hyperoxia-induced strain-independent reductions in heart rate, QTcB and ST-interval and increases in QRS, LF HRV and standard deviation of RR-intervals were observed. In Bmp4(+/)(-) mice only, increased PR-interval (PR-I) (24 hrs), P-wave duration (P-d; 18 and 21-24 hrs), PR-I minus P-d (PR - Pd; 24 hrs) and root of the mean squared differences of successive RR-intervals (24 hrs) were found during hyperoxia (p < 0.05).

DISCUSSION

Elevated baseline LF and TP HRV in Bmp2(+/)(-) mice suggests an altered autonomic nervous system regulation of cardiac function in these mice. However, this was not related to strain specific differences in responses to 24 hrs hyperoxia. During hyperoxia, Bmp4(+/-) mice were the most susceptible in terms of atrioventricular conduction changes and risk of atrial fibrillation, which may have important implications for patients treated with O2 who also harbor Bmp4 mutations. This study demonstrates significant ECG and HRV responses to 24 hrs hyperoxia in mice, which highlights the need to further work on the genetic mechanisms associated with cardiac susceptibility to hyperoxia.

The neural guidance receptor Plexin C1 delays melanoma progression

Plexin C1 is a type I transmembrane receptor with intrinsic R-Ras GTPase activity, which regulates cytoskeletal remodeling and adhesion in normal human melanocytes. Melanocytes are pigment-producing cells of the epidermis, precursors for melanoma, and express high levels of Plexin C1, which is lost in melanoma in vitro and in vivo. To determine if Plexin C1 is a tumor suppressor for melanoma, we introduced Plexin C1 into a primary human melanoma cell line, and phenotypes including migration, apoptosis, proliferation and tumor growth in mice were analyzed. Complimentary studies in which Plexin C1 was silenced in human melanocytes were performed. Plexin C1 significantly inhibited migration and proliferation in melanoma, whereas in melanocytes, loss of Plexin C1 increased migration and proliferation. In mouse xenografts, Plexin C1 delayed tumor growth of melanoma at early time points, but tumors eventually escaped the suppressive effects of Plexin C1, due to Plexin C1-dependent activation of the pro-survival protein Akt. R-Ras activation stimulates melanoma migration. Plexin C1 lowered R-Ras activity in melanoma and melanocytes, consistent with inhibitory effects of Plexin C1 on migration of melanocytes and melanoma. To determine if R-Ras is expressed in melanocytic lesions in vivo, staining of tissue microarrays of nevi and melanoma were performed. R-Ras expression was highly limited in melanocytic lesions, being essentially confined to primary melanoma, and almost completely absent in nevi and metastatic melanoma. These data suggest that loss of Plexin C1 in melanoma may promote early steps in melanoma progression through suppression of migration and proliferation, but pro-survival effects of Plexin C1 ultimately abrogate the tumor suppressive effects of Plexin C1. In primary melanoma, loss of Plexin C1 may function in early steps of melanoma progression by releasing inhibition of R-Ras activation, and stimulating migration.

Impaction femoral allografting at revision hip arthroplasty

We report the long-term results of revision total hip replacement using femoral impaction allografting with both uncemented and cemented Freeman femoral components. A standard design of component was used in both groups, with additional proximal hydroxyapatite coating in the uncemented group. A total of 33 hips in 30 patients received an uncemented component and 31 hips in 30 patients a cemented component. The mean follow-up was 9.8 years (2 to 17) in the uncemented group and 6.2 years (1 to 11) in the cemented group. Revision procedures (for all causes) were required in four patients (four hips) in the uncemented group and in five patients (five hips) in the cemented group. Harris hip scores improved significantly in both groups and were maintained independently of the extent of any migration of the femoral component within the graft or graft–cement mantle.

Relevance of the expression "obs stable" in nursing observations: retrospective study

OBJECTIVE

To ascertain whether use of the term "obs stable" with respect to the nursing observations is so liberal as to render it meaningless.

DESIGN

Retrospective study.

SETTING

Three teaching hospitals in London, United Kingdom.

METHODS

We searched progress notes for the current admission of 46 inpatients for entries containing the phrases "obs stable" and "observations stable," and reviewed the nursing observations recorded during the 24 hour period preceding each entry containing at least one phrase. We calculated the frequency of abnormalities and of persistent abnormalities (defined as occurring in every observation) observed during these 24 hour periods, and the range of observation values over a 24 hour period if at least two observations had been recorded.

RESULTS

We found at least one entry in 36 (78%) progress notes (95% confidence interval 66% to 90%). Observations in the 24 hours preceding an entry included at least one abnormality for 113 (71%) of 159 cases and at least one persistent abnormality for 31 (19%). The most frequently occurring abnormalities were tachypnoea (respiratory rate ≥20 breaths/min) and hypotension (systolic blood pressure <100 mm Hg). An abnormality occurred in the observations immediately preceding an entry in 42% of cases. Mean ranges of observations over 24 hours were within the limits of normal diurnal variation, although we found that some instances of greater than normal variability were described as "stable."

CONCLUSIONS

The expression "obs stable" does not reliably indicate normal observations or variations in observations within physiological limits. Doctors should avoid using the expression altogether or clarify it with further information.

P1-07-23: Absolute Quantification of Estrogen Receptor alpha in Breast Cancer

Estrogen receptor alpha (ER) is the first biomarker to have been clinically validated as a predictor of cancer therapy response. Measurements of tumor ER expression were based on radiolabeled ligand binding to receptor present in tumor lysates. Despite substantial tissue requirement, lack of specificity for ER isoforms (alpha versus beta) or receptor integrity, quantitative determination of tumor ER content (fmol/mg total protein) was possible. Introduction of anti-ER antibodies later permitted immunohistochemical (***lHC) evaluation of ER expression. IHC determination of ER status in newly diagnosed breast cancer is now a standard of care. While these IHC assays have been shown to be as predictive of endocrine responsiveness as ligand binding assays, they remain semi-quantitative at best reporting tumor ER status either categorically (e.g. + or -) or as a numeric score which is subjective and lacks a linear relationship with endocrine responsiveness. Thus the lack of precision for quantifying ER as a predictive biomarker is one of the most important unresolved issues in breast cancer. We are working to develop a proteomic liquid chromatography-mass spectrometry (LC-MS) assay to help resolve this issue. Samples included recombinant ER (rER), immunoprecipitated (IP) rER, and IP ER from MCF7 cells. ER was digested with trypsin, lyophilised and solubilised in 5 femto-mol/microliter (100 μl) heavy peptide internal standard mix. ER peptides were resolved by LC (100 μl/minute) and detected by selected reaction monitoring MS. The area under the total ion chromatogram for each peptide were used to quantify the amount of analyte present in each sample as a single point reference to the signal of the heavy peptide spike. An 11 point calibration curve (0.1-1000 fmol on column (o/c)) of light peptides with each point in the curve spiked with 100 fmol heavy peptide was also produced to determine assay characteristics such as limits of detection (LOD), limits of quantification (LOQ), linearity, accuracy and precision. Three ER peptides were selected for quantification as they gave the greatest LOD, LOQ, linearity as well as reasonable intra- and inter-assay precision following multiple digestions of rER (intra = 3 digestions in 1 day; inter = 9 digestions over 3 weeks).

Conservative surgery in the management of a benign ovarian cystic teratoma presenting as a rectal mass: a case report

Ovarian cystic teratomas constitute 10-15% of all ovarian tumours and are the most common ovarian neoplasms found in adolescence and during pregnancy. Nevertheless, ovarian cystic teratomas have also been described in patients aged 1-91 years. We report an unusual case of a benign ovarian cystic teratoma presenting as a rectal mass that was managed surgically using radical resection by a multidisciplinary team. This case report highlights the importance of preoperative investigations including colonoscopy and radiological investigations. A dedicated pelvic radiologist/pathologist and the involvement of a multidisciplinary team at the time of initial diagnosis and a gynaecologist and colorectal surgeon at the time of surgery will lead to an accurate diagnosis and the most appropriate treatment. Although rare, erosion of an ovarian dermoid into the rectum should be considered in young women who have an atypical presentation and are found to have a lesion in the rectum with biopsies indicating benign pathology.