Structural and functional implications of SLC13A3 and SLC9A6 mutations: an in silico approach to understanding intellectual disability

BACKGROUND

Intellectual disability (ID) is a condition that varies widely in both its clinical presentation and its genetic underpinnings. It significantly impacts patients' learning capacities and lowers their IQ below 70. The solute carrier (SLC) family is the most abundant class of transmembrane transporters and is responsible for the translocation of various substances across cell membranes, including nutrients, ions, metabolites, and medicines. The SLC13A3 gene encodes a plasma membrane-localized Na+/dicarboxylate cotransporter 3 (NaDC3) primarily expressed in the kidney, astrocytes, and the choroid plexus. In addition to three Na + ions, it brings four to six carbon dicarboxylates into the cytosol. Recently, it was discovered that patients with acute reversible leukoencephalopathy and a-ketoglutarate accumulation (ARLIAK) carry pathogenic mutations in the SLC13A3 gene, and the X-linked neurodevelopmental condition Christianson Syndrome is caused by mutations in the SLC9A6 gene, which encodes the recycling endosomal alkali cation/proton exchanger NHE6, also called sodium-hydrogen exchanger-6. As a result, there are severe impairments in the patient's mental capacity, physical skills, and adaptive behavior.

METHODS AND RESULTS

Two Pakistani families (A and B) with autosomal recessive and X-linked intellectual disorders were clinically evaluated, and two novel disease-causing variants in the SLC13A3 gene (NM 022829.5) and the SLC9A6 gene (NM 001042537.2) were identified using whole exome sequencing. Family-A segregated a novel homozygous missense variant (c.1478 C > T; p. Pro493Leu) in the exon-11 of the SLC13A3 gene. At the same time, family-B segregated a novel missense variant (c.1342G > A; p.Gly448Arg) in the exon-10 of the SLC9A6 gene. By integrating computational approaches, our findings provided insights into the molecular mechanisms underlying the development of ID in individuals with SLC13A3 and SLC9A6 mutations.

CONCLUSION

We have utilized in-silico tools in the current study to examine the deleterious effects of the identified variants, which carry the potential to understand the genotype-phenotype relationships in neurodevelopmental disorders.

Constructing custom-made radiotranscriptomic signatures from CT angiograms: an application in COVID-19 vascular inflammation

Background

Advances in computational methodologies have enabled processing of large datasets originating from imaging studies. However, most imaging biomarkers suffer from a lack of direct links with underlying biology, as they are only observationally correlated with pathophysiology.

Purpose

To develop and validate a novel AI-assisted image analysis platform, by applying quantitative radiotranscriptomics that quantifies cytokine-driven vascular inflammation from routine CT angiograms (CTA) performed as part of clinical care in COVID-19.

Methods

We used this platform to train the radiotranscriptomic signature C19-RS, derived from the perivascular space around the aorta and the internal mammary artery in routine chest CTAs, to best describe cytokine-driven vascular inflammation, defined using transcriptomic profiles from RNA sequencing data from human arterial biopsies (A). This signature was validated externally in 358 clinically indicated CT pulmonary angiograms from patients with or without COVID-19 from 3 different geographical regions.

Results

First, 22 patients who had a CTA before the pandemic underwent repeat CTA <6 months post COVID-19 infection (B). Compared with 22 controls (matched for age, gender, and BMI) C19-RS was increased only in the COVID-19 group (C). Next, C19-RS was calculated in a cohort of 331 patients hospitalised during the pandemic, and was higher in COVID-19 positives (adjusted OR=2.97 [95% CI: 1.43–6.27], p=0.004, D). C19-RS had prognostic value for in-hospital mortality in COVID-19, with HR=3.31 ([95% CI: 1.49–7.33], p=0.003) and 2.58 ([95% CI: 1.10–6.05], p=0.028) in two testing cohorts respectively (E, F), adjusted for clinical factors and biochemical biomarkers of inflammation and myocardial injury. The corrected HR for in-hospital mortality was 8.24 [95% CI: 2.16–31.36], p=0.002 for those who received no treatment with dexamethasone, but only 2.27 [95% CI: 0.69–7.55], p=0.18 in those who received dexamethasone subsequently to the C19-RS based image analysis, suggesting that vascular inflammation may have been a therapeutic target of dexamethasone in COVID-19. Finally, C19-RS was strongly associated (r=0.61, p=0.0003) with a whole blood transcriptional module representing dysregulation of coagulation and platelet aggregation pathways.

Conclusion

We present the first proof of concept study that combines transcriptomics with radiomics to provide a platform for the development of machine learning derived radiotranscriptomics analysis of routine clinical CT scans for the development of non-invasive imaging biomarkers. Application in COVID-19 produced C19-RS, a marker of cytokine-driven inflammation driving systemic activation of coagulation, that predicts in-hospital mortality and identifies people who will have better response to anti-inflammatory treatments, allowing targeted therapy. This AI-assisted image analysis platform may have applications across a wide range of vascular diseases, from infections to autoimmune diseases.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): EPSRC, British Heart Foundation, NIHR

Automated deep learning quantification of epicardial adiposity on cardiac CT predicts atrial fibrillation risk immediately following cardiac surgery and long-term

Introduction

Epicardial adipose tissue (EAT) is a visceral fat deposit within the pericardial sac which surrounds the heart myocardium and coronary arteries. The automated quantification of EAT volume is possible from routine CCTA scans via a deep-learning approach. The use of automated EAT quantification for the assessment of atrial fibrillation (AF) risk in the post-operative period, and longer-term, has not been previously investigated.

Purpose

To apply a deep-learning approach for automated segmentation of EAT from routine CCTA scans to assess the immediate post-operative and long-term risk of AF conveyed by EAT.

Methods

A deep-learning automated EAT segmentation tool using a 3D Residual-U-Net neural network architecture for 3D volumetric segmentation of CCTA data was created and trained on over 2800 consecutive CCTA performed as part of clinical care in patients with stable chest pain from 2015 onwards within the European arm of the Oxford Risk Factors And Non Invasive Imaging (ORFAN) Study. External validation in 817patients demonstrated excellent correlation between machine and human expert (CCC = 0.972). The prognostic value of deep-learning derived EAT volume was assessed in the AdipoRedOx Study (n=253; UK patients undergoing cardiac surgery) against both immediate in-hospital outcomes and longer-term outcomes from UK-wide NHS data, with adjustment for AF risk factors.

Results

There were 97 cases of new-onset AF in the immediate post-operative period (38.3%). EAT volume was found to be an independent predictor of post-operative AF regardless of body mass index. Utilising the median EAT volume as the cut point, the adjusted hazard ratio (HR [95% CI]) for risk of new-onset post-operative AF in-hospital was 1.56 [1.09–3.85], p&lt;0.01 (Figure 1A). In receiver-operator characteristic analysis EAT volume added significant incremental prognostic power for the discrimination of in-hospital post-operative AF over a traditional risk factor model ΔAUC=0.101, p&lt;0.01 (Figure 1B).

Over a median follow-up period of 89 months there were 48 unique cases (19%) of confirmed AF found in nation-wide NHS hospital episode statistics data for the AdipoRedOx cohort. EAT volume was found to be a significant independent predictor of long-term AF. Utilising the median EAT volume as the cut point, the adjusted HR for risk of new-onset long-term AF following cardiac surgery was 1.25 [1.08–3.17], p&lt;0.01 (Figure 1C).

Conclusions

Automatically segmented EAT volume measured using a deep learning network predicts risk of both short-term new onset AF following cardiac surgery, and long-term risk of AF in the 7 years following the surgery independently of BMI and AF risk factors. This suggests that EAT is a potent mediator of AF risk in the post cardiac surgery setting.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation - TG/19/2/34831EU Commission - 965286

Scanning 2d barcodes on vaccine vials to link vials to immunized child, a pilot study

Background

Vaccine stockouts contribute to millions of children missing their routine immunizations globally. This is often due to inadequate forecasting and management of vaccine stocks, especially in low and middle-income countries, such as Pakistan, already characterized by suboptimal coverage. Tracking vaccines via 2D barcodes on each vial, could improve management of vaccine stocks. Vial level data can then be linked to Electronic Immunisation Registry (EIR) data (2D Bar codes already used), facilitating data quality improvements which could unlock programmatic gains. Our aim was to test feasibility and acceptability of scanning vaccine vials in a “live” setting.

Methods

We conducted a pilot in 12 vaccination sites in Karachi/Pakistan. Vaccinators were divided into 3 groups and allocated to use one of the following: their existing android phone (government of Sindh's Zindagi Mehfooz [Safe life; ZM-EIR]); a Zebra touch computer; a handheld scanner. The box of dummy vaccine vials of pneumococcal conjugate vaccine (PCV) and oral polio vaccine (OPV) each with a 2D barcode on it, was scanned by the stockroom manager prior to deployment. Vaccinators were required to scan the corresponding dummy vial and immunization cards while working. We integrated the OneScanTM API on the ZM-EIR to link vial to child data and evaluated the vaccinator's experience through thematic analysis of interviews.

Results

2,310 vaccine vials were scanned and linked to immunized children (Zebra Touch Computer 72.6%, Android phone 19%, Handheld device 8.4%). Overall, vaccinators gave positive feedback and highlighted that scanning vials would simplify their work and save time, contingent on the program going paperless. Likewise, managers outlined digitally tracked vials would greatly reduce stock mismanagement.

Conclusions

Linking vaccine vial to child is a feasible and effective solution for vaccine stock management, acceptable by both vaccinators and stock managers.

Key messages

Linking vial to child is an acceptable method for accurate vaccine stock management and usage, improving forecasting and reducing stock outs. Linking vial to child will better facilitate rapid tracking of reported adverse events from vaccinated child back to the exact vaccine vial.

1-year impact of COVID-19 on childhood immunizations in Pakistan: analysis of &gt; 3.7 million children

 

Covid-19 has universally disrupted primary health care, but routine childhood immunizations are one the most affected services. We analyzed big data in vaccines for measuring the 1-year impact of Covid-19 on outline childhood immunizations for the 48 million population in the Sindh province of Pakistan. We extracted and analyzed >3.7m real-time immunization records of 0-23 months old children from the Sindh Government's Electronic Immunization Registry (EIR). Using a 6-month baseline preceding the COVID-19 lockdown, we quantified the lockdown's (March 23-May 9, 2020) impact on daily immunization rates by geographical area and the change in coverage rates at the one-year mark since the lockdown. The lockdown resulted in 53% drop in the number of immunizations. The impact in rural areas as more than in urban areas (54.9% decline vs 47.5% decline from baseline), and slums had a slightly larger decrease in immunization coverage than non-slum areas (53.8% vs. 51.3%). Of 1,246,321 children who missed immunizations during first year of the pandemic, 76% of these children were eventually vaccinated by the end of March 2021. Similarly, of the 417,553 children who had dropped out during the initial 7-week national lockdown (March 23-May 10, 2020), 79% were immunized by March 2021. Our analysis of EIR data shows that the catch-up and recovery of coverage rates have primarily been driven through intensive outreach vaccination efforts instead of an increase in demand. One year since the onset of the pandemic, the average daily immunization doses administered through outreach increased by 121 percent above baseline estimates. In contrast, vaccines administered at immunization clinics were still 22 percent below baseline. The example of Pakistan shows LMICs can successfully deploy mitigation strategies to catch up with missed children during Covid-19 and sustain routine childhood immunizations to close immunity gaps.

Key messages

Although the lockdown resulted in a 53% drop in immunizations, at the 1-year mark since the pandemic started, 76% of children who missed immunizations are vaccinated.

Pakistan data shows LMICs can rectify routine immunization coverage and immunity gaps and rebound successfully to their pre-COVID-19 coverage rates.

Automated quantification of epicardial adipose tissue on CCTA via deep-learning detection of the pericardium: clinical implications

Background

Epicardial adipose tissue (EAT) is a visceral fat deposit within the pericardial sac which surrounds the heart myocardium and coronary arteries. EAT volume has been demonstrated to be strongly associated with the development and prognosis of cardiovascular diseases, but its measurement is subjective and challenging in practice.

Purpose

To develop a deep-learning approach for automated segmentation of EAT from routine CCTA scans, that could assist clinical interpretation of CCTA.

Methods

A deep-learning method using a 3D Residual-U-Net neural network architecture for 3D volumetric segmentation of CCTA data was created. The network was trained on a diverse sample of 1900 CCTAs, each manually segmented by a single expert, drawn from the UK sites of the Oxford Risk Factors And Non-invasive imaging (ORFAN) Study. Three iterations of feedback learning were used to fine tune the algorithm for the segmentation of the whole heart within the bounds of the pericardium. In each iteration, the machine analysed sets of 100–250 unannotated CCTAs unseen by the machine which were then corrected by experts. EAT volumes were calculated by automated thresholding of adipose tissue (−190HU through −30HU) from within the bound of the pericardial segment (Figure 1). The network was then applied to 817 unseen CCTAs from US sites of the ORFAN Study. These scans were also segmented for ground truth by two experts blind to all other data. Comparisons between machine vs expert total pericardial volume and EAT volume were made using Lin's concordance correlation coefficient (CCC). The algorithm was then applied externally in 1588 CCTAs from the SCOTHEART trial (UK), and the EAT volume was automatically calculated for each case. Cross-sectional associations between standardised EAT volumes and prevalent AF and CAD were performed.

Results

Within both the internal (UK ORFAN sites) and external (USA ORFAN sites) validation cohorts correlation between human and machine segmented total pericardium and EAT was excellent, with CCC of 0.97 for both volumes (external validation cohort shown in Figure 2A). Utilising SCOTHEART CCTAs with automatically segmented EAT volumes, a multivariable-adjusted logistic regression model accounting for risk factors of age, sex, BMI, hypertension, diabetes mellitus, valvular disease, and previous heart surgery found that EAT volumes were significantly associated with prevalent AF, with odds ratio (OR) per 1 SD increase of EAT volume of 1.20 (95% CI, 1.06 to 1.44; P=0.03). A similar model for prevalent CAD, adjusted for age, sex, BMI, hypertension, non-HDL cholesterol, diabetes mellitus, and coronary artery calcium score resulted in an OR per 1 SD increase of EAT volume of 1.26 (95% CI, 1.10 to 1.45; P=0.001) (Figure 2B).

Conclusion

Highly accurate, reproducible, and instantaneous EAT volume quantification is possible utilising deep-learning detection of the whole human heart within the pericardial sac.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): British Heart FoundationNational Institute for Health Research - Oxford University Hospitals Biomedical Research Centre Figure 1Figure 2

A human arterial transcriptomic signature predicts major adverse cardiac events and identifies novel, redox-related therapeutic targets within the vascular wall

Background

The transcriptomic profile of the human vascular wall is implicated in a range of pathologies. RNA sequencing technologies allow for interrogation of gene expression patterns that are associated with clinical outcomes and can guide future research and drug development.

Purpose

To apply discovery network transcriptomics to internal mammary arteries (IMAs) obtained from patients undergoing cardiac surgery, in order to identify redox-related molecular pathways within the vascular wall that can be treated therapeutically.

Methods

Arm 1 included 377 patients in whom segments of IMA were used for ex-vivo quantification of NADPH-stimulated superoxide production by lucigenin-enhanced chemiluminescence. Arm 2 included 205 patients in whom bulk RNA sequencing was performed in RNA isolated from IMA, and the WGCNA package used for the analyses. The association with future incidence of major adverse cardiac events (MACE: cardiovascular death, non-fatal myocardial infarction, and stroke) was assessed using Cox regression models (adjusted for age, sex, hypertension, dyslipidaemia, diabetes mellitus, body mass index, smoking, and plasma TNFa).

Results

Over a median follow-up of 4.84 years [IQR: 2.03–7.14], 38 (11.2%) MACE occurred in Arm 1. High arterial NADPH-stimulated superoxide was independently associated with MACE risk (Adj. HR [95% CI]: 2.62 [1.13–6.07] high group, p=0.02). Unsupervised transcriptomic analysis in Arm 2 allowed identification of 10 coexpressed gene “modules”. Eigengenes summarising modular coexpression signatures were then correlated with NADPH-stimulated superoxide revealing the red module (a) as the most significant (rho=0.19, p=0.01). In survival analysis the red module showed significant correlation with MACE (Adj. HR [95% CI]: 1.40 [1.00–1.95] per SD, p=0.04). For an optimal cut-off, patients with high eigengene values for the red module showed a 4-fold higher risk of MACE (b), and significantly higher arterial oxidative stress (c). Enrichment analysis (performed with Enrichr) of genes in the red module revealed “Electron Transport Chain”, “Oxidative phosphorylation”, “Striated Muscle Contraction Pathway”, and “Glycolysis and Gluconeogenesis” amongst the top enriched pathways (d).

Conclusion

We present for the first time a novel human arterial transcriptomic signature reflecting changes in redox state, which identifies long-term cardiovascular risk. Targeting pathways in the vasculature related with the mitochondrial electron transport chain, the contractile mechanism, or glucose metabolism may lead to the development of novel therapeutics in cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): EPSRC-EP/N509711/1-2119518British Heart Foundation Figure 1

A novel arterial redox-specific machine learning-derived radiomic signature of perivascular adipose tissue predicts cardiac mortality from routine CCTA

Background

Vascular oxidative stress is involved in inflammation and atherogenesis. Vascular inflammation induces spatial changes in perivascular adipose tissue (PVAT) composition, which can be detected by radiomic analysis of coronary computed tomography angiography (CCTA) images.

Purpose

To explore the association of arterial oxidative stress with long-term risk of major adverse cardiovascular events (MACE). To develop a radiomic signature to identify high oxidative stress non-invasively using CCTA. Finally, to assess the ability of this signature to predict future cardiac risk.

Methods

Arm 1 included 272 patients undergoing cardiac surgery. Segments of internal mammary artery (IMA) were used for ex-vivo quantification of NADPH-stimulated and Vas2870 (pan-NOX inhibitor) inhibitable superoxide production by lucigenin-enhanced chemiluminescence. Eighty-two of these patients with CCTA scans available constituted Arm 2. Peri-IMA PVAT was segmented and used to extract 1,616 radiomic features, which, after filtering (40 final features), were utilised to train extreme gradient boosting, a machine learning algorithm, to predict high arterial oxidative stress. Arm 3 included a nested cohort of 308 participants (41 suffering cardiac death and 267 matched controls) from the CRISP-CT (Cardiovascular RISk Prediction using Computed Tomography) study to externally validate the redox-specific signature developed in Arm 2 for cardiac risk prediction.

Results

Over a median follow-up of 40 months, 18 (6.6%) MACE (cardiovascular death, non-fatal myocardial infarction, and stroke) occurred in Arm 1. High arterial NADPH-stimulated superoxide was independently associated with MACE risk (Adj. HR[95% CI]: 1.61 [1.04–2.53] per SD, p=0.03, adjusted for age, sex, diabetes, hypertension, hyperlipidemia, smoking, obesity, and plasma TNFa). Unsupervised hierarchical clustering of radiomic features from peri-IMA PVAT segments in Arm 2 identified two distinct clusters (A) that differed in NADPH stimulated (p=0.01) and Vas2870 inhibitable (p=0.04) IMA superoxide (B), supporting the hypothesis that PVAT mapping can capture changes corresponding to differential levels of underlying vascular redox state. This prompted the development of a radiomic signature specific to PVAT alterations associated with high vascular oxidative stress, which was validated in Arm 3 (AUC:0.61, p=0.026, C). The novel signature was able to stratify cardiac risk in the validation set, independently of the Fat Attenuation Index, epicardial adipose tissue volume, high-risk plaque features, and obstructive CAD (Adj. HR [95% CI]:2.56 [1.35–4.87], p=0.004, D).

Conclusion

Increased arterial oxidative stress predicts cardiac risk in patients with advanced atherosclerosis. We present for the first time a novel, non-invasive CCTA imaging biomarker reflecting changes in vascular redox state by radiomic phenotyping of perivascular space, which stratifies cardiac risk beyond standard and newer risk assessment methods.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation, National Institute of Health Research, Oxford Biomedical Research Centre

Using mobile immunization vans to cover under-served populations in hard-to-reach areas

Background

In Pakistan, only 66% of children receive their basic vaccinations. However, the figure masks significant inequalities in vaccine coverage between urban and rural residences, slums and areas distantly located from EPI centers. Frequent outbreaks of vaccine-preventable diseases such as polio and measles, in urban cities like Karachi, signal the need for expanding vaccine services to underserved areas. In Apr'19, we introduced the Mobile Immunization Van initiative in Karachi in collaboration with EPI Sindh. Currently, two vans are deployed in hard-to-reach areas and slums to immunize under-2 children for routine vaccines.

Methods

Before the van visit, mobilization efforts are conducted in targeted areas to encourage caretakers to bring their child for vaccination. On the day of visit, the van is parked at a central location, and announcements are played on a loudspeaker to attract caregivers. All vaccinations are administered in the van, and entries are recorded in Government's Digital Immunization Registry along with GIS coordinates of immunized children. The data is then automatically transferred on to a web-dashboard for analysis and tracking.

Results

From Apr'19 to Jan'20, the vans have vaccinated 2,867 children, out of which 50% had never been immunized prior to the van visit. Of those who received their follow-up vaccines from the van, 80% were at least 4 weeks beyond from their vaccine due date. GIS analysis of van data confirmed that immunizations were conducted in slums, and areas distantly located from EPI centers. Moreover, compared to government outreach activity, proportion of BCG, Penta3 and Measles1 administrations in slums was higher through the vans by 5%, 6%, and 4% respectively.

Conclusions

The vans provide an opportunity for immunizing never-vaccinated children and children defaulting on their vaccine schedule, from the most vulnerable geographies, while simultaneously enrolling them in the Government's EPI Program for effective tracking.

Key messages

The mobile vans help achieve universal immunization coverage through provision of vaccine services in slum and rural hard-to-reach areas with limited access to government-provided services. The mobile vans help vaccinate and capture never-immunized children into the Government’s EPI records, reducing the number of children missed through routine services.

AB1183 TERIPARATIDE SWITCH TO BIOSIMILAR - IS IT COST EFFECTIVE?

Background:

Teriparatide is an effective treatment option for osteoporosis however NICE restricts its use to patients with high disease burden. This was based on cost effectiveness evaluation of the originator (Forsteo®) and would be different for recently introduced generic preparation.

Objectives:

We wished to evaluate the current prescribing behaviour prior to a potential switch to generic version and associated cost savings.

Methods:

All patients prescribed Teriparatide since the commencement of specialist osteoporosis service in Aug 2014 at our University teaching hospital covering 350,000 population were included. Data was extracted from electronic database with full access to demographics, population characteristics, disease parameters and medication history.

Results:

113 patients were prescribed Teriparatide over five years. Mean age of participants was 76 yrs (53-96). They had on average three comorbidities (0-8) with most common being hypertension (n=44, 38.9%) and inflammatory arthritis (n=21, 18.5%). Sixteen (14.1%) individuals had concurrent corticosteroids. Median number of fractures prior to therapy were four (0-12). Prior treatments included oral therapy (n= 90,79.6%), IV zoledronate (n=22, 19.4%) and denosumab (n=19, 16.8%). 66 (58.4%) of patients only had one prior bone active medication. Mean duration of prior therapy was 62.4 months (9-192 months). 17 (15.0%) patients had chronic kidney disease with lowest eGFR of 38. 41 (36.2%) had Vit D level between 40-75 nmol/L. Median T score was -3.8 (-2.1 - -6.0) which improved to -3.4 (-2.9 - -3.9) after two years.

Conclusion:

Our real-world study shows that teriparatide is used predominantly in complex, multi-morbid older individuals with several prior fractures. Despite that teriparatide remains effective for a wide range of individuals including those with inflammatory arthritis and/or concurrent steroid use. Neither moderate CKD nor mild Vit D insufficiency seems to impact its efficacy. This is in line with recent meta-analysis of real life teriparatide use in complex osteoporosis with multimorbidity. Our study should enhance clinicians’ confidence in its prescribing. It’s notable that the use is higher than current estimates based on NICE cost effectiveness analysis for eligibility of teriparatide. Instead of annual predicted use of 4.8/100,000 population, it was prescribed to 6.4/100,000. This could potentially have a cost impact however the introduction of a generic version would mitigate against it. We calculated our savings to be over £125,000 if all patients were switched. These savings at national level would hopefully improve access to a wider patient cohort and perhaps allow earlier use in the treatment paradigm.

Disclosure of Interests:

Tahreem Akram: None declared, Maham Siddique: None declared, Hafiz A. Javed: None declared, Julie Begum: None declared, Joanne Fourmy: None declared, Muhammad Khurram Nisar Grant/research support from: Muhammad Nisar undertakes clinical trials and received support (including attendance at conferences, speaker fees and honoraria) from Roche, Chugai, MSD, Abbvie, Pfizer, BMS, Celgene, Novartis and UCB

, Consultant of: Muhammad Nisar undertakes clinical trials and received support (including attendance at conferences, speaker fees and honoraria) from Roche, Chugai, MSD, Abbvie, Pfizer, BMS, Celgene, Novartis and UCB

, Speakers bureau: Muhammad Nisar undertakes clinical trials and received support (including attendance at conferences, speaker fees and honoraria) from Roche, Chugai, MSD, Abbvie, Pfizer, BMS, Celgene, Novartis and UCB

Iron–manganese–titanium (1 : 1 : 2) oxide composite thin films for improved photocurrent efficiency

Fe₂MnTi₃O₁₀–MnTiO₃ composite thin films with a photocurrent density of 1.88 mA cm⁻² at 0.2 V have been deposited through AACVD.

Relationships of body habitus and SUV indices with signal-to-noise ratio of hepatic (18)F-FDG PET

OBJECTIVE

Tissue accumulation of (18)F-FDG is quantified as standardised uptake value (SUV), which may be expressed as the voxel maximum (SUVmax) or mean (SUVmean). SUVmax/SUVmean may be a marker of hepatic steatosis, while the coefficient of variation (CV) of SUV may be a marker of hepatic fat distribution heterogeneity (HFDH). Alternatively, they may reflect low signal-to-noise ratio ('noise') in obese persons in whom hepatic steatosis is common. The study aim was to compare the impact of body size on noise versus SUV and CT density (CTD).

METHODS

Dynamic PET was performed (30×1min frames) following FDG injection in 60 patients undergoing routine PET/CT. Hepatic FDG clearance was measured using Patlak-Rutland graphical analysis with abdominal aorta as input. Noise was quantified as the standard deviation (SD) of the plot residuals (ignoring the first 2 frames), normalised to the intercept (NRMSD). SUVmax, SUVmean and CTD were measured from 60min whole body PET/CT. CV of SUV and SD of CTD were quantified in 28/60 patients using texture analysis.

RESULTS

NRMSD correlated with weight (r=0.49; p<0.0001) and BMI (r=0.48; p=0.0001). SUVmax, SUVmean, SUVmax/SUVmean, CV of SUV, CTD, and SD of CTD all correlated strongly with weight and BMI (p<0.0001). However, they correlated weakly with NRMSD, the strongest being SUVmax (r=0.34; p=0.008) and SD of CTD (r=0.42; n=28; p=0.026).

CONCLUSIONS

Noise is increased in overweight/obese persons but has little effect on SUV indices, CTD and their variabilities. SUVmax/SUVmean and CV of SUV are therefore, to some extent, markers of hepatic steatosis and HFDH, respectively.

Investigation on the structural, dielectric and impedance analysis of manganese substituted cobalt ferrite i.e., Co1−xMnxFe2O4 (0.0 ≤ x ≤ 0.4)

The microstructure and cation distribution of Co_1−xMnxFe₂O₄ were investigated and correlated with their electrical properties. Here, Mn substitution enhances the resistive properties which make them favorable for high-frequency applications.

Texture analysis of (125)I-A5B7 anti-CEA antibody SPECT differentiates metastatic colorectal cancer model phenotypes and anti-vascular therapy response

BACKGROUND

We aimed to test the ability of texture analysis to differentiate the spatial heterogeneity of (125)I-A5B7 anti-carcinoembryonic antigen antibody distribution by nano-single photon emission computed tomography (SPECT) in well-differentiated (SW1222) and poorly differentiated (LS174T) hepatic metastatic colorectal cancer models before and after combretastatin A1 di-phosphate anti-vascular therapy.

METHODS

Nano-SPECT imaging was performed following tail vein injection of 20 MBq (125)I-A5B7 in control CD1 nude mice (LS174T, n=3 and SW1222, n=4), and CA1P-treated mice (LS174T, n=3; SW1222, n=4) with liver metastases. Grey-level co-occurrence matrix textural features (uniformity, homogeneity, entropy and contrast) were calculated in up to three liver metastases in 14 mice from control and treatment groups.

RESULTS

Before treatment, the LS174T metastases (n=7) were more heterogeneous than SW1222 metastases (n=12) (uniformity, P=0.028; homogeneity, P=0.01; contrast, P=0.045). Following CA1P, LS174T metastases (n=8) showed less heterogeneity than untreated LS174T controls (uniformity, P=0.021; entropy, P=0.006). Combretastatin A1 di-phosphate-treated SW1222 metastases (n=11) showed no difference in texture features compared with controls (all P>0.05).

CONCLUSIONS

Supporting the potential for novel imaging biomarkers, texture analysis of (125)I-A5B7 SPECT shows differences in spatial heterogeneity of antibody distribution between well-differentiated (SW1222) and poorly differentiated (LS174T) liver metastases before treatment. Following anti-vascular treatment, LS174T metastases, but not SW1222 metastases, were less heterogeneous.

Routine histological analysis of a macroscopically normal gallbladder--a review of the literature

BACKGROUND

70,000 cholecystectomies were performed in the United Kingdom in 2011-2012. Currently it is standard practice to submit all gallbladder specimens for routine histology to exclude malignancy. The aim of this systematic review was to establish whether a normal macroscopic appearance to the gallbladder at the time of cholecystectomy is sufficient to rule out malignancy and therefore negate the need for routine histology.

METHODS

Relevant articles that were published between 1966 and January 2013 were identified through electronic databases.

RESULTS

21 studies reported on 34,499 histologically analysed specimens. 172/187 (92%) of gallbladder cancers demonstrated intra-operative macroscopic abnormality. Studies that opened the specimens intra-operatively identified all cancers, whereas gross macroscopic visualization resulted in 15 potentially missed cancers (p = 0.10). In patients of European ethnicity, gallbladder cancer in a macroscopically normal looking gallbladder was identified in only one study; however all of these patients were above the age of 60. The incidence of gallbladder cancer was significantly raised in ethnic groups from high risk areas (p = 0.0001).

CONCLUSIONS

A macroscopically normal gallbladder in patients of European ethnicity under the age of 60 may not require formal histopathology. The best method for intra-operative examination may involve opening the specimen to allow inspection of the mucosa and wall, however this needs further investigation. In the context of the volume of gallbladder surgery being performed there is the potential for significant cost and time savings.

Differences in regional bone metabolism at the spine and hip: a quantitative study using (18)F-fluoride positron emission tomography

SUMMARY

This study showed that regional bone blood flow and (18)F-fluoride bone plasma clearance measured by positron emission tomography are three times lower at the hip than the lumbar spine.

INTRODUCTION

Measurements of effective bone plasma flow (K (1)), bone plasma clearance (K ( i )) and standardised uptake values (SUV) using (18)F-fluoride positron emission tomography ((18)F-PET) provide a useful means of studying regional bone metabolism at different sites in the skeleton. This study compares the regional (18)F-fluoride kinetics and SUV at the hip and lumbar spine (LS).

METHODS

Twelve healthy postmenopausal women with no history of metabolic bone disease apart from two with untreated osteoporosis were recruited. Each subject underwent 60-min dynamic (18)F-PET scans at the LS and proximal femur two weeks apart. K (1), K ( i ) and SUV were measured at the LS (mean of L(1)-L(4)), femoral neck (FN), total hip (TH) and femoral shaft (FS). Differences between sites were assessed using the nonparametric Kruskal-Wallis test with a Bonferroni correction for multiple comparisons.

RESULTS

Values of K (1), K ( i ) and SUV at the FN, TH and FS were three times lower than at the LS (p = 0.003). Amongst the proximal femur sites, K ( i ) and SUV were lower at the FS compared with the FN and TH, and SUV was lower at the TH compared with the FN (all p < 0.05). The volume of distribution was lower at the TH and FS compared with the LS (p < 0.05).

CONCLUSION

The lower values of K (1), K ( i ) and SUV at the hip suggest that lower bone blood flow in the proximal femur is an important factor explaining the principal reason for the differences in bone fluoride kinetics between the LS and hip sites.

Precision of ¹⁸F-fluoride PET skeletal kinetic studies in the assessment of bone metabolism

We assessed the precision of lumbar spine (18)F-PET measurements based on 58 scans performed on 20 postmenopausal women. The percentage coefficient of variation (%CV) (95% confidence interval) was 9.2% (7.5-11.8) for standardised uptake values, 11.7% (9.5-14.9) for plasma clearance measurements using the Patlak method and 14.5% (11.7-18.5) for plasma clearance measurements using the Hawkins three-compartment model.

INTRODUCTION

(18)F-Fluoride positron emission tomography ((18)F-PET) is a non-invasive technique that allows the assessment of regional bone turnover in patients with metabolic bone disease. Knowledge of the precision errors of (18)F-PET measurements is important for planning the number of subjects required for research studies.

METHODS

Twenty osteoporotic postmenopausal women had (18)F-PET scans of the lumbar spine at 0, 6 and 12 months after stopping long-term bisphosphonate treatment. No significant changes in the PET measurements were seen over the 12-month period, and the data were deemed suitable for a precision study. Precision errors were evaluated for standardised uptake values (SUVs) and for the fluoride plasma clearance to bone mineral (K (i)) determined using the Patlak and Hawkins methods. Precision errors were expressed as the %CV and were calculated for the mean L1-L4 region and for individual vertebrae.

RESULTS

%CV (95% confidence interval) for the L1-L4 region was 9.2% (7.5-11.8) for SUV, 11.7% (9.5-14.9) for K (i) measured using the Patlak method and 14.5% (11.7-18.5) for K (i) measured using the Hawkins method. There was no significant difference between precision errors obtained for the L1-L4 region and those obtained for a single vertebra.

CONCLUSIONS

SUV measurements showed the smallest precision error followed by the Patlak method, while the Hawkins method gave the largest error. Measuring a smaller region of interest did not increase the precision error, suggesting that the factor determining the errors may be scanner calibration.

Regional bone metabolism at the lumbar spine and hip following discontinuation of alendronate and risedronate treatment in postmenopausal women

The aim of this study was to examine the effects of bisphosphonate discontinuation on bone metabolism at the spine and hip measured using (18) F-fluoride PET. Bone metabolism at the spine remained stable following discontinuation of alendronate and risedronate at 1 year but increased in the hip in the alendronate group only.

INTRODUCTION

Bisphosphonates such as alendronate (ALN) or risedronate (RIS) have persistent effects on spine BMD following discontinuation.

METHODS

Positron emission tomography (PET) was used to examine regional bone metabolism in 20 postmenopausal women treated with ALN (n = 11) or RIS (n = 9) for a minimum of 3 years at screening (range 3-9 years, mean 5 years for both groups). Subjects underwent a dynamic scan of the lumbar spine and a static scan of both hips at baseline and 6 and 12 months following treatment discontinuation. (18) F-fluoride plasma clearance (K(i)) at the spine was calculated using a three-compartment model. Standardised uptake values (SUV) were calculated for the spine, total hip, femoral neck and femoral shaft. Measurements of BMD and biochemical markers of bone turnover were also performed.

RESULTS

With the exception of a significant decrease in spine BMD in the ALN group, BMD remained stable. Bone turnover markers increased significantly from baseline by 12 months for both study groups. Measurements of K(i) and SUV at the spine and femoral neck did not change significantly in either group. SUV at the femoral shaft and total hip increased significantly but in the ALN group only, increasing by 33.8% (p = 0.028) and 24.0% (p = 0.013), respectively.

CONCLUSIONS

Bone metabolism at the spine remained suppressed following treatment discontinuation. A significant increase in SUV at the femoral shaft and total hip after 12 months was observed but for the ALN group only. This study was small, and further clinical studies are required to fully evaluate the persistence of BP treatment.

Use of ultrasonic pachymetry for measurement of changes in corneal thickness in mouse corneal transplant rejection

BACKGROUND/AIMS

Diagnosis of rejection in the mouse model of corneal transplantation is based on subjective judgement of loss of graft transparency. The aims of this study were to (1) evaluate a pachymetry technique to measure changes in mouse corneal thickness and (2) correlate increases in transplant thickness with clinical and histological features of rejection.

METHODS

Orthotopic corneal allografts (C57BL/6 strain donor) and syngeneic grafts were performed in A/J mice. Graft transparency was graded and corneal thickness measured by pachymetry on alternate days. Transverse sections of donor cornea excised from eyes representative of clinical opacity grades 1-4 were prepared, photographed, graft section thickness measured and stromal graft-infiltrating cells counted. Intraobserver and interobserver variations in pachymetry were statistically tested.

RESULTS

Graft thickness, as measured by pachymetry, increased with each clinical opacity grade. Thickness for opacity grades 0, 1 and 2 was less than 300 microm in all recipients. Graft thickness for grades 3 and 4 was greater than 300 microm in all cases. For measurements up to 400 mum, there was a good correlation between thickness as measured by in vivo pachymetry and in histopathological sections. The mean interobserver bias was -11.35 microm, while the mean intraobserver bias was +3.96 microm. Stromal cellularity increased with increasing corneal thickness up to approximately 300 microm.

CONCLUSION

In vivo graft pachymetry provides a new and reliable way to objectively diagnose rejection in the mouse model of corneal transplantation.

DNA vaccination with VP2 gene of very virulent infectious bursal disease virus (vvIBDV) delivered by transgenic E. coli DH5alpha given orally confers protective immune responses in chickens

The efficacy of different doses of oral DNA vaccines carrying VP2 gene of vvIBDV delivered by E. coli DH5alpha was studied and compared with purified VP2 recombinant expression plasmid DNA vaccine injected intradermally and whole virus vaccine either from homologous virus or from commercial source. The recombinant plasmid pRc-VP2 was transformed in a non-pathogenic strain of E. coli, the DH5alpha and designated as EC/pRC-VP2. Oral immunization of maternal antibody free broiler chickens at 7 and 14-day-old with different dosages of EC/pRc-VP2 elicited specific humoral immune response as measured by ELISA. Protection in different groups was calculated through clinical signs, gross and histopathological lesions, bursa of Fabricius to body weight ratio, humoral and cellular immune responses and mortality in the chickens. Vaccination with EC/pRc-VP2 at the dose rate of 10(9)CFU per chicken conferred 95.4% protection of the chickens against the challenge with homologous virulent field strain of vvIBDV. Protection afforded by attenuated vero cell adapted UAF-06 strain of vvIBDV was comparable (94%) to that by EC/pRc-VP2 and pRc-VP2 vaccines, which was significantly higher (P<0.05) than the protection provided by a commercial attenuated IBDV stain D-78 vaccine (D-78 vaccine was used as positive control due to its frequent use in the field for vaccination of poultry chickens) and other control groups in the study. The results revealed that DNA vaccines against IBDV may be successfully done by adopting bacterial-vectored oral delivery system and vaccination with homologous vvIBDV (UAF-06) conferred significantly higher protection as compared with imported non-homologous commercial IBDV vaccine.

Protection capability of recombinant plasmid DNA vaccine containing VP2 gene of very virulent infectious bursal disease virus in chickens adjuvanted with CpG oligodeoxynucleotide

In the present study the efficacy of recombinant plasmids DNA vaccine encoding VP2 gene of very virulent strain of infectious bursal disease virus (vvIBDV) isolated from Pakistan was investigated with or without coadministration of cytocine-phosphate-guanine oligodeoxynucleotide (CpG ODN) to protect the chickens against the disease. VP2 gene of vvIBDV was successfully amplified by reverse transcription-polymerase chain reaction (RT-PCR) and was cloned into eukaryotic expression plasmid vector, which consisted of human cytomegalovirus (HCMV) immediate early enhancer and promoter, adenopartite leader sequences and SV-40 polyadenylation signal, and this was designated as pRc-VP2. Seven-day-old maternal antibodies free chickens were intramuscularly injected with 500 microg of pRc-VP2 with or without CpG ODN twice at 1-week interval. At the age of 21 days the broiler chickens were challenged with 10(5) EID(50) of homologous strain of IBDV and observed for 14 days post-challenge. Immunization with pRc-VP2 plus CpG ODN conferred protection in 93% of the chickens as evidenced by the absence of clinical signs, atrophy of bursa of Fabricius (BF) and mortality followed by the group vaccinated with attenuated IBD vaccine and boosted with killed oil based IBDV vaccine, which conferred 90% protection. The protection of chickens injected with pRc-VP2 alone was 67% where as only 20% of the chickens in the negative control group were protected. However, enzyme-linked immunosorbent assay (ELISA) antibody titre in the group vaccinated with pRc-VP2 plus CpG ODN were significantly higher (P<0.05) than the group vaccinated with pRc-VP2 alone as well as the group vaccinated with commercial attenuated IBDV vaccine boosted with commercial oil adjuvanted killed IBDV vaccine. Responsiveness to a mitogenic lectin, phytoheamagglutinin-P was significantly reduced in group immunized with conventional vaccines (live boosted with killed) as compared to all the other groups (P<0.05). The results revealed that co-administration of recombinant plasmids with CpG ODN could protect chickens efficiently from IBDV challenge.

Trp53-dependent DNA-repair is affected by the codon 72 polymorphism

Trp53 is arguably the most critical tumour suppressor gene product that inhibits malignant transformation. Besides mutations that inactivate Trp53 functions, genetic polymorphisms have been suggested to be risk factors for cancer. A polymorphic site at codon 72 in exon 4 encodes either an arginine amino acid (Trp53(72R)) or a proline residue (Trp53(72P)). Previous studies have shown that the Trp53(72R) form is more efficient in apoptosis induction, whereas the Trp53(72P) form was suggested to induce G1 arrest better. Here we report that Trp53(72P) is more efficient than Trp53(72R) in specifically activating several Trp53-dependent DNA-repair target genes in several cellular systems. Moreover, using isogenic cell lines and several DNA-repair assays, we show that Trp53(72P) cells have a significantly higher DNA-repair capacity than the Trp53(72R) cells. Furthermore, Trp53(72P)-expressing cells exhibit reduced micronuclei formation compared to Trp53(72R)-expressing cells, suggesting that genomic instability is reduced in these cells. Together, the data highlight the functional differences between the Trp53 polymorphic variants, and suggest that their expression status may influence cancer risk.

Comparison of retrobulbar anesthesia and intracameral anesthesia using preservative free bupivacaine hydrochloride 0.5% in phacoemulsification with posterior chamber intraocular lens implantation

OBJECTIVE

To compare the retrobulbar anesthesia and intracameral anesthesia using preservative-free bupivacaine hydrochloride 0.5% in terms of effectiveness, complications and comfort to the patient during phacoemulsification with posterior chamber intraocular lens implantation.

METHODS

This was a hospital based comparative study of two methods of anesthesia, conducted at LRBT Free Eye and Cancer Hospital, Lahore from January to July 2000. Study included 200 patients with uncomplicated age-related cataract, equally divided in two groups on simple random basis. Group A (100 patients) received the retrobulbar anesthesia and Group B (100 patients) received the intracameral anesthesia with bupivacaine hydrochloride 0.5% for phacoemulsification with posterior chamber intraocular lens implantation. Outcome measures like pain, visual acuity, intraocular pressure and anterior chamber reaction were compared.

RESULTS

On day 1, 79% of the patients in group A and 82% patients in group B had unaided visual acuity ranging between 6/6-6/18. On day 7, this was 88% in group A and 89% group B. On day 1, 99% in group A and 98% in group B had <1+ cells in the anterior chamber while on day 7 this increased up to 100%. On day 1, 97% in group A and 98% group B had intraocular pressure less than 20 mmHg. On day 7, it increased up to 100% in both groups. 97% patients in group A and 96% patients in group B had painless surgery. Results were analysed using computer software SPSS version 10.0. Results showed no significant statistical difference between two groups in terms of pain, visual acuity, intraocular pressure, anterior chamber reaction and patient comfort.

CONCLUSION

In the hands of expert surgeons and in selected patients, intracameral anesthesia with preservative-free bupivacaine hydrochloride 0.5% is a safe and effective technique of ocular anesthesia for phacoemulsification with posterior chamber intraocular lens implantation.