AMFR dysfunction causes autosomal recessive spastic paraplegia in human that is amenable to statin treatment in a preclinical model

Hereditary spastic paraplegias (HSP) are rare, inherited neurodegenerative or neurodevelopmental disorders that mainly present with lower limb spasticity and muscle weakness due to motor neuron dysfunction. Whole genome sequencing identified bi-allelic truncating variants in AMFR, encoding a RING-H2 finger E3 ubiquitin ligase anchored at the membrane of the endoplasmic reticulum (ER), in two previously genetically unexplained HSP-affected siblings. Subsequently, international collaboration recognized additional HSP-affected individuals with similar bi-allelic truncating AMFR variants, resulting in a cohort of 20 individuals from 8 unrelated, consanguineous families. Variants segregated with a phenotype of mainly pure but also complex HSP consisting of global developmental delay, mild intellectual disability, motor dysfunction, and progressive spasticity. Patient-derived fibroblasts, neural stem cells (NSCs), and in vivo zebrafish modeling were used to investigate pathomechanisms, including initial preclinical therapy assessment. The absence of AMFR disturbs lipid homeostasis, causing lipid droplet accumulation in NSCs and patient-derived fibroblasts which is rescued upon AMFR re-expression. Electron microscopy indicates ER morphology alterations in the absence of AMFR. Similar findings are seen in amfra-/- zebrafish larvae, in addition to altered touch-evoked escape response and defects in motor neuron branching, phenocopying the HSP observed in patients. Interestingly, administration of FDA-approved statins improves touch-evoked escape response and motor neuron branching defects in amfra-/- zebrafish larvae, suggesting potential therapeutic implications. Our genetic and functional studies identify bi-allelic truncating variants in AMFR as a cause of a novel autosomal recessive HSP by altering lipid metabolism, which may potentially be therapeutically modulated using precision medicine with statins.

Expanding the genotype-phenotype landscape of PDE10A-associated movement disorders

BACKGROUND

Phosphodiesterase 10A (PDE10A) controls body movements by regulating cyclic adenosine monophosphate signaling in the basal ganglia. Two classes of PDE10A variants are reported with distinctive genotype-phenotype correlation. The autosomal recessive mutations in the GAF-A and catalytic domains are associated with compromised membrane localization, and manifest with infantile onset chorea, developmental, and cognition delay with normal brain MRI. Conversely, autosomal dominant mutations in the GAF-B domain cause protein aggregates which results in childhood onset chorea in the context of normal cognition and development, with striatal lesions.

METHODS

Phenotypic characteristics of affected individuals with PDE10A mutations belonging to a single family were recorded. In addition, Sanger sequencing and in silico analysis were used to identify the mutations. Homozygosity mapping was applied together with whole exome sequencing.

RESULTS

Four individuals from a consanguineous family affected with PDE10A mutations were observed for up to 40 years. Although these individuals displayed a clinical phenotype attributed to the recessive GAF-A mutations, they revealed a bi-allelic GAF-B mutation (c.883G > A:p. D295 N; p.Asp295Asn) that was segregated with all affected individuals. In addition to chorea, we observed peculiar foot deformities and pronounced social phobia, with normal brain MRI. In silico structural analysis suggested that the GAF-B mutation blocked allosteric PDE10A activation. The resulting lack of PDE10A activity likely phenocopies GAF-A mutations, and this is achieved through a distinct mechanism.

CONCLUSIONS

Collectively, our findings demonstrate the association of recessive and dominant phenotypes of known variants, and further expands the genotype-phenotype landscape of PDE10A-associated movement disorders.

Statistical Modeling and Analysis of Online Examinations in Covid-19

In this paper, the authors build a model that predicts the grade point from a collection of independent variables including student characteristics and exam marks achieved in four marketing management courses using data from four courses. The data from four courses in marketing management, for an off-line class in a master’s in business management program taught in 2019 and the same set of four courses in marketing management taught to an on-line class in 2020 was taken. Although the number of students enrolled was almost equal, and the courses, despite being offered a year apart, were nearly comparable in structure and content, the teaching and assessment for 2019 was conducted offline, whereas it was conducted online in 2020. In the set of four courses offered in 2019 using the offline mode, the exam was proctored and offline but for the same courses offered in 2020, the final exam was also proctored but online. The authors predicted that if exams were taken without any misconduct, the prediction model would have the same explanatory power for all exams, and that if there was malpractice, the explanatory power would be lower. Their findings show that the two datasets are similar; there are variations in the independent variables that statistically and significantly predicted the Grade Point Average (GPA). The R-squared statistic suggests that the model for prediction is strong. Hence there is reason to believe that malpractice was taking place when the examinations were online, in spite of it being proctored. The goal of this paper is to provide teachers with practical ideas for administering proctored tests in their online courses.

Dynamics of nondegenerate vector solitons in a long-wave-short-wave resonance interaction system

In this paper, we study the dynamics of an interesting class of vector solitons in the long-wave-short-wave resonance interaction (LSRI) system. The model that we consider here describes the nonlinear interaction of long wave and two short waves and it generically appears in several physical settings. To derive this class of nondegenerate vector soliton solutions we adopt the Hirota bilinear method with the more general form of admissible seed solutions with nonidentical distinct propagation constants. We express the resultant fundamental as well as multisoliton solutions in a compact way using Gram-determinants. The general fundamental vector soliton solution possesses several interesting properties. For instance, the double-hump or a single-hump profile structure including a special flattop profile form results in when the soliton propagates in all the components with identical velocities. Interestingly, in the case of nonidentical velocities, the soliton number is increased to two in the long-wave component, while a single-humped soliton propagates in the two short-wave components. We establish through a detailed analysis that the nondegenerate multisolitons in contrast to the already known vector solitons (with identical wave numbers) can undergo three types of elastic collision scenarios: (i) shape-preserving, (ii) shape-altering, and (iii) a shape-changing collision, depending on the choice of the soliton parameters. Here, by shape-altering we mean that the structure of the nondegenerate soliton gets modified slightly during the collision process, whereas if the changes occur appreciably then we call such a collision as shape-changing collision. We distinguish each of the collision scenarios, by deriving a zero phase shift criterion with the help of phase constants. Very importantly, the shape-changing behavior of the nondegenerate vector solitons is observed in the long-wave mode also, along with corresponding changes in the short-wave modes, and this nonlinear phenomenon has not been observed in the already known vector solitons. In addition, we point out the coexistence of nondegenerate and degenerate solitons simultaneously along with the associated physical consequences. We also indicate the physical realizations of these general vector solitons in nonlinear optics, hydrodynamics, and Bose-Einstein condensates. Our results are generic and they will be useful in these physical systems and other closely related systems including plasma physics when the long-wave-short-wave resonance interaction is taken into account.

Bleb revision with bleborhexis and clear corneal lamellar patch graft for overhanging cystic bleb

Background:

Trabeculectomy is associated with several complications. One of the common complications with mitomycin assisted trabeculectomy is thin cystic bleb leading to bleb leak, hypotony and infections. Various technique of bleb repair and reconstruction have been described, such as conjunctival advancement, or scleral, pericardial or corneal patch graft.

Purpose:

To demonstrate bleb revision by bleborhexis and clear corneal lamellar patch graft for a patient with thin cystic leaking bleb leading to hypotony and decreased vision.

Synopsis:

This was a 75-year-old one-eyed lady, diagnosed with primary angle-closure glaucoma in both eyes with absent light perception in the left eye, had undergone a combined trabeculectomy and cataract surgery in the right eye 6 years ago. She presented with diminution of vision (6/18p), introacular pressure (IOP) of of 6 mmHg, thin cystic leaking overhanging bleb, and dysesthesia. Bleb repair by bleborhexis with lamellar corneal patch graft was performed. Bleborhexis is a technique in which the overhanging fibrosed thin cystic conjunctival bleb is peeled off the cornea smoothly to leave a uniform clear corneal surface. Clear cornea, uniform diffuse bleb, well-formed anterior chamber with and IOP of 15 mmHg was noted on the first post-operative day, with a vision of 6/12p. This procedure helped meticulous reconstruction of the bleb, early recovery of vision, maintanance of normotensive eye, and save the eye from potential infections.

Highlights:

Bleborhexis with lamellar corneal patch graft provides for an easy and a elegant surgical technique with minimal corneal tissue damage, faster healing and patient comfort. It could be the favored technique in patients with thin overhanging clebs.

Video link:

https://youtu.be/GeFYHWToueU

Lowering of intraocular pressure after phacoemulsification in primary open-angle and angle-closure glaucoma: Correlation with lens thickness

Purpose:

To assess anterior chamber configuration changes during phacoemulsification in primary angle-closure suspect (PACS/PAC) and primary open-angle glaucoma (POAG).

Methods:

Prospective observational comparative study of anterior segment optical coherence tomography (AS-OCT) findings before and after phacoemulsification on three groups of patients (PACS/PAC, POAG, and controls). Data were collected over a period of 9 months. Main outcome measures included mean change in anterior chamber depth (ACD), angle opening distance (AOD), and trabecular iris space area (TISA).

Results:

153 patients (51 PACS/PAC, 51 POAG, and 51 controls) were included in the study. Change in all parameters (ACD, AOD at 500 um, and AOD at 750 um) between the groups demonstrated a greater change in PACS/PAC as compared to POAG and controls. AOD at 750 μm in the temporal quadrant, which has been considered to be having the highest correlation or best representation of the angle, increased in all groups after phacoemulsification (463.59 ± 10.99 vs. 656.27 ± 9.73 mm in PACS; 521.29 ± 16.36 vs. 674.37 ± 8.72 mm in POAG; 549.27 ± 12.40 vs. 702.82 ± 13.04 mm in controls, (P < 0.001). After phacoemulsification, intraocular pressure (IOP) decreased by 2.75 ± 1.17 mm Hg in PACS/PAC (P < 0.001), 2.14 ± 1.33 mm Hg in POAG and 1.90 ± 1.25 mm Hg in controls and it was statistically significant in the PACS group compared to control (P < 0.001).

Conclusion: Phacoemulsification with intraocular lens implantation is associated with increase in the ACD and angle parameters and a corresponding decrease in IOP. Findings were more pronounced in PACS/PAC suggesting early phacoemulsification may be a treatment option in this group.

A persistent plaque on the back of the hand

We report the case of a 75-year-old woman presenting with acrodermatitis chronica atrophicans affecting the right hand dorsum, developing after an insect bite sustained in Greece. Diagnosis was confirmed by serology, PCR and histopathological findings. The plaque resolved following a 3-week course of oral doxycycline.

Whole-exome sequencing identifies multiple pathogenic variants in a large South Indian family with primary open-angle glaucoma

Purpose:

To identify the pathogenic variants associated with primary open-angle glaucoma (POAG) using whole-exome sequencing (WES) data of a large South Indian family.

Methods:

We recruited a large five-generation South Indian family (n = 84) with a positive family history of POAG (n = 19). All study participants had a comprehensive ocular evaluation. We performed WES for 16 samples (nine POAG and seven unaffected controls) since Sanger sequencing of the POAG candidate genes (MYOC, OPTN, and TBK1) showed no genetic variation. We used an in-house pipeline for prioritizing the pathogenic variants based on their segregation among the POAG individual.

Results:

We identified one novel and five low-frequency pathogenic variants with consistent co-segregation in all affected individuals. The variant c.G3719A in RPGR-interacting domain of RPGRIP1 that segregated heterozygously with the six POAG cases is distinct from variants causing photoreceptor dystrophies, reported affecting the RPGR protein complex signaling in primary cilia. The cilia in trabecular meshwork (TM) cells has been reported to mediate the intraocular pressure (IOP) sensation. Furthermore, we identified a novel c.A1295G variant in Rho guanine nucleotide exchange factors Gene 40 (ARHGEF40) and a likely pathogenic variant in the RPGR gene, suggesting that they may alter the RhoA activity essential for IOP regulation.

Conclusion:

Our study supports that low-frequency pathogenic variants in multiple genes and pathways probably affect Primary Open Angle Glaucoma’s pathogenesis in the large South Indian family. Furthermore, it requires larger case-controls to perform family-based association tests and to strengthen our analysis.

Factors associated with mortality in patients with COVID-19 admitted to intensive care: a systematic review and meta-analysis

Identification of high-risk patients admitted to intensive care with COVID-19 may inform management strategies. The objective of this meta-analysis was to determine factors associated with mortality among adults with COVID-19 admitted to intensive care by searching databases for studies published between 1 January 2020 and 6 December 2020. Observational studies of COVID-19 adults admitted to critical care were included. Studies of mixed cohorts and intensive care cohorts restricted to a specific patient sub-group were excluded. Dichotomous variables were reported with pooled OR and 95%CI, and continuous variables with pooled standardised mean difference (SMD) and 95%CI. Fifty-eight studies (44,305 patients) were included in the review. Increasing age (SMD 0.65, 95%CI 0.53-0.77); smoking (OR 1.40, 95%CI 1.03-1.90); hypertension (OR 1.54, 95%CI 1.29-1.85); diabetes (OR 1.41, 95%CI 1.22-1.63); cardiovascular disease (OR 1.91, 95%CI 1.52-2.38); respiratory disease (OR 1.75, 95%CI 1.33-2.31); renal disease (OR 2.39, 95%CI 1.68-3.40); and malignancy (OR 1.81, 95%CI 1.30-2.52) were associated with mortality. A higher sequential organ failure assessment score (SMD 0.86, 95%CI 0.63-1.10) and acute physiology and chronic health evaluation-2 score (SMD 0.89, 95%CI 0.65-1.13); a lower PaO₂ :F_I O₂ (SMD -0.44, 95%CI -0.62 to -0.26) and the need for mechanical ventilation at admission (OR 2.53, 95%CI 1.90-3.37) were associated with mortality. Higher white cell counts (SMD 0.37, 95%CI 0.22-0.51); neutrophils (SMD 0.42, 95%CI 0.19-0.64); D-dimers (SMD 0.56, 95%CI 0.43-0.69); ferritin (SMD 0.32, 95%CI 0.19-0.45); lower platelet (SMD -0.22, 95%CI -0.35 to -0.10); and lymphocyte counts (SMD -0.37, 95%CI -0.54 to -0.19) were all associated with mortality. In conclusion, increasing age, pre-existing comorbidities, severity of illness based on validated scoring systems, and the host response to the disease were associated with mortality; while male sex and increasing BMI were not. These factors have prognostic relevance for patients admitted to intensive care with COVID-19.

Clinical and Genetic Characterization of Craniosynostosis in Saudi Arabia

Background: Craniosynostosis (CS) is defined as pre-mature fusion of one or more of the cranial sutures. CS is classified surgically as either simple or complex based on the number of cranial sutures involved. CS can also be classified genetically as isolated CS or syndromic CS if the patient has extracranial deformities. Currently, the link between clinical and genetic patterns of CS in the Saudi population is poorly understood. Methodology: We conducted a retrospective cohort study among 28 CS patients, of which 24 were operated and four were not. Clinical and genetic data were collected between February 2015 and February 2019, from consenting patient's families. The electronic chart data were collected and analyzed including patient demographics, craniofacial features, other anomalies and dysmorphic features, operative data, intra cranial pressure (ICP), parent consanguinity and genetic testing results. Results: The most common deformity in our population was trigonocephaly. The most performed procedure was cranial vault reconstruction with fronto-orbital advancement, followed by posterior vault distraction osteogenesis and suturectomy with barrel staving. Genetics analysis revealed pathogenic mutations in FGFR2 (6 cases), TWIST1 (3 cases), ALPL (2 cases), and TCF12 (2 cases), and FREM1 (2 case). Conclusion: Compared to Western countries, our Saudi cohort displays significant differences in the prevalence of CS features, such as the types of sutures and prevalence of inherited CS. The genomic background allows our phenotype-genotype study to reclassify variants of unknown significance. Worldwide, the sagittal suture is the most commonly affected suture in simple CS, but in the Saudi population, the metopic suture fusion was most commonly seen in our clinic. Further studies are needed to investigate the characteristics of CS in our population in a multicenter setting.

Fetal growth at different gestational periods and risk of impaired childhood growth, low childhood weight and obesity: a prospective birth cohort study

OBJECTIVE

To examine the longitudinal associations of fetal growth with adverse child growth outcomes and to assess whether maternal metabolic factors modify the associations.

DESIGN

Prospective cohort study.

SETTING

Born in Guangzhou Cohort Study, China.

POPULATION

A total of 4818 mother-child pairs.

METHODS

Fetal growth was assessed according to estimated fetal weight (EFW) from 22 weeks of gestation until birth and the measurement of the birthweight. Fetal growth Z-scores were computed from random effects in the multilevel linear spline models to represent fetal size in early pregnancy (22 weeks of gestation) and growth in mid-pregnancy (22-27 weeks of gestation), early third trimester (28-36 weeks of gestation) and late third trimester (≥37 weeks of gestation).

MAIN OUTCOME MEASURES

Z-scores for childhood stunting, low weight, overweight or obesity, length/height for age (LAZ/HAZ), weight for age (WAZ) and body mass index for age (BMIZ) at the age of 3 years. Adjusted associations were examined using multiple Poisson or linear regression models.

RESULTS

Increased Z-scores of fetal size in early pregnancy and growth in mid-pregnancy and early third trimester were associated with a higher risk of childhood overweight or obesity (risk ratios 1.25-1.45). Fetal growth in each period was negatively associated with stunting and low weight, with the strongest associations observed for fetal size in early pregnancy and growth in mid-pregnancy. The results for continuous outcomes (LAZ/HAZ, WAZ and BMIZ) were similar. The associations of fetal growth with overweight or obesity in childhood were stronger among mothers who were underweight and who were overweight or obese than among mothers of normal weight.

CONCLUSIONS

Accelerated fetal growth before 37 weeks of gestation is associated with children who are overweight or obese, whereas the critical period for stunting and low weight occurs before 28 weeks of gestation.

TWEETABLE ABSTRACT

Fetal growth during different periods is differentially associated with childhood stunting, underweight and overweight or obesity.

Nondegenerate solitons and their collisions in Manakov systems

Recently, we have shown that the Manakov equation can admit a more general class of nondegenerate vector solitons, which can undergo collision without any intensity redistribution in general among the modes, associated with distinct wave numbers, besides the already-known energy exchanging solitons corresponding to identical wave numbers. In the present comprehensive paper, we discuss in detail the various special features of the reported nondegenerate vector solitons. To bring out these details, we derive the exact forms of such vector one-, two-, and three-soliton solutions through Hirota bilinear method and they are rewritten in more compact forms using Gram determinants. The presence of distinct wave numbers allows the nondegenerate fundamental soliton to admit various profiles such as double-hump, flat-top, and single-hump structures. We explain the formation of double-hump structure in the fundamental soliton when the relative velocity of the two modes tends to zero. More critical analysis shows that the nondegenerate fundamental solitons can undergo shape-preserving as well as shape-altering collisions under appropriate conditions. The shape-changing collision occurs between the modes of nondegenerate solitons when the parameters are fixed suitably. Then we observe the coexistence of degenerate and nondegenerate solitons when the wave numbers are restricted appropriately in the obtained two-soliton solution. In such a situation we find the degenerate soliton induces shape-changing behavior of nondegenerate soliton during the collision process. By performing suitable asymptotic analysis we analyze the consequences that occur in each of the collision scenario. Finally, we point out that the previously known class of energy-exchanging vector bright solitons, with identical wave numbers, turns out to be a special case of nondegenerate solitons.

Cardiometabolic disease, comorbidities and risk of death: findings using data from large-scale electronic health records

Background

Myocardial infarction (MI), stroke and diabetes are separately associated with increased risk of mortality but it is uncertain if their combined effects are proportional, amplified or less than the expected risk of each disease individually. In addition, patients with these conditions tend to also have other long-term comorbidities. How the relationship between cardiometabolic disease and risk of death is modified by the presence of comorbidity is unclear.

Purpose

We investigated the separate and combined effects of MI, stroke and diabetes on all-cause mortality, and examined the impact of comorbidity on these associations.

Methods

We selected a patient cohort of 2,007,731 (51% women) aged ≥16 years at registration with their general practice, using large-scale UK primary care electronic health records that were linked to the national death registry. We identified patients with a recorded diagnosis of MI, stroke, diabetes or none before 2005 (baseline), and classified the patient cohort into mutually exclusive categories of their baseline disease status. For each group, we also extracted information on another major 53 long-term conditions prior to baseline. The cohort was followed until death, deregistration from the practice or censored at the end of study (31 Dec 2014). We used Cox regression, and tested for departure from additivity and multiplicativity to assess interaction.

Results

At baseline, the mean age of the cohort was 51 (SD=18) years and 7% (N=145,910) had a cardiometabolic disease. Over an average follow-up of 7 (SD=3) years, 270,036 died (mean age of death=79 years). After adjusting for baseline age and sex, the hazard ratio (HR) (95% confidence interval [CI]), relative to those without cardiometabolic disease, were as follows: diabetes=1.53 (1.51 to 1.55), MI=1.54 (1.51 to 1.56), stroke=1.87 (1.84 to 1.90), diabetes and MI=2.16 (2.09 to 2.23), MI and stroke=2.39 (2.28 to 2.49), diabetes and stroke=2.56 (2.47 to 2.65), and all three=3.17 (2.95 to 3.41). After adjusting for the 53 comorbidities, the HR (95% CI) were attenuated: diabetes=1.37 (1.35 to 1.39), MI=1.25 (1.23 to 1.27), stroke=1.49 (1.46 to 1.52), diabetes and MI=1.60 (1.55 to 1.65), MI and stroke=1.52 (1.45 to 1.59), diabetes and stroke=1.91 (1.84 to 1.98), and all three=1.77 (1.64 to 1.91). The results did not materially changed with adjustment for smoking and deprivation level. Test for interaction revealed some minor synergistic effects when cardiometabolic disease co-occurred but excess risks were lower than expected for two combined vs individual disease effects; no significant interaction was seen for all three vs individual disease effects.

Conclusion

MI, stroke and diabetes are associated with excess mortality, which was partly due to associated chronic conditions. We found no evidence that the co-occurrence of these three conditions contribute to a higher excess mortality than expected from each of them separately.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): NIHR Oxford Biomedical Research Centre; Oxford Martin School, University of Oxford

An interpretable model for incident heart failure prediction with uncertainty estimation

Background

Forecasting incident heart failure is a critical demand for prevention. Recent research suggested the superior performance of deep learning models on the prediction tasks using electronic health records. However, even with a relatively accurate predictive performance, the major impediments to the wider use of deep learning models for clinical decision making are the difficulties of assigning a level of confidence to model predictions and the interpretability of predictions.

Purpose

We aimed to develop a deep learning framework for more accurate incident heart failure prediction, with provision of measures of uncertainty and interpretability.

Methods

We used a longitudinal linked electronic health records dataset, Clinical Practice Research Datalink, involving 788,880 patients, 8.3% of whom had an incident heart failure diagnosis. To embed the uncertainty estimation mechanism into the deep learning models, we developed a probabilistic framework based on a novel transformer deep learning model: deep Bayesian Gaussian processes (DBGP). We investigated the performance of incident heart failure prediction and uncertainty estimation for the model and validated it using an external held-out dataset. Diagnoses, medications, and age for each encounter were included as predictors. By comparing the uncertainty, we investigated the possibility of identifying the correct predictions from wrong ones to avoid potential misclassification. Using model distillation meant to mimic a well-trained complex model with simple models, we investigated the importance of associations between diagnoses, medications and heart failure with an interpretable linear regression component learned from DBGP.

Results

The DBGP achieved high precision with 0.941 as AUROC for external validation. More importantly, it showed the uncertainty information could distinguish the correct predictions from wrong ones, with significant difference (p-value with 500 samples) between distribution of uncertainties for negative predictions (3.21e-69 between true negative and false negative), and positive predictions (3.39e-22 between true positive and false positive). Utilising the distilled model, we can specify the contribution of each diagnosis and medication to heart failure prediction. For instance, Losartan/Fosinopril, Bisoprolol and Left bundle-branch block showed strong association to heart failure incidence with coefficient 0.11 (95% CI: 0.10, 0.12), 0.09 (0.08, 0.11) and 0.09 (0.07, 0.11) respectively; Peritoneal adhesions, Trochanteric bursitis and Galactorrhea showed strong disassociations with coefficient −0.07 (−0.09, −0.05), −0.07 (−0.09, −0.04) and −0.06 (−0.08, −0.04) individually.

Conclusions

Our novel probabilistic deep learning framework adds a measure of uncertainty the prediction and helps to mitigate misclassification. Model distillation provides an opportunity to interpret deep learning models and offers a data-driven perspective for risk factor analysis.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Oxford Martin School,University of Oxford; NIHR Oxford Biomedical Research Centre, University of Oxford

BEHRT-HF: an interpretable transformer-based, deep learning model for prediction of incident heart failure

Background/Introduction

Predicting incident heart failure has been challenging. Deep learning models when applied to rich electronic health records (EHR) offer some theoretical advantages. However, empirical evidence for their superior performance is limited and they remain commonly uninterpretable, hampering their wider use in medical practice.

Purpose

We developed a deep learning framework for more accurate and yet interpretable prediction of incident heart failure.

Methods

We used longitudinally linked EHR from practices across England, involving 100,071 patients, 13% of whom had been diagnosed with incident heart failure during follow-up. We investigated the predictive performance of a novel transformer deep learning model, “Transformer for Heart Failure” (BEHRT-HF), and validated it using both an external held-out dataset and an internal five-fold cross-validation mechanism using area under receiver operating characteristic (AUROC) and area under the precision recall curve (AUPRC). Predictor groups included all outpatient and inpatient diagnoses within their temporal context, medications, age, and calendar year for each encounter. By treating diagnoses as anchors, we alternatively removed different modalities (ablation study) to understand the importance of individual modalities to the performance of incident heart failure prediction. Using perturbation-based techniques, we investigated the importance of associations between selected predictors and heart failure to improve model interpretability.

Results

BEHRT-HF achieved high accuracy with AUROC 0.932 and AUPRC 0.695 for external validation, and AUROC 0.933 (95% CI: 0.928, 0.938) and AUPRC 0.700 (95% CI: 0.682, 0.718) for internal validation. Compared to the state-of-the-art recurrent deep learning model, RETAIN-EX, BEHRT-HF outperformed it by 0.079 and 0.030 in terms of AUPRC and AUROC. Ablation study showed that medications were strong predictors, and calendar year was more important than age. Utilising perturbation, we identified and ranked the intensity of associations between diagnoses and heart failure. For instance, the method showed that established risk factors including myocardial infarction, atrial fibrillation and flutter, and hypertension all strongly associated with the heart failure prediction. Additionally, when population was stratified into different age groups, incident occurrence of a given disease had generally a higher contribution to heart failure prediction in younger ages than when diagnosed later in life.

Conclusions

Our state-of-the-art deep learning framework outperforms the predictive performance of existing models whilst enabling a data-driven way of exploring the relative contribution of a range of risk factors in the context of other temporal information.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): National Institute for Health Research, Oxford Martin School, Oxford Biomedical Research Centre

Stratified effects of blood pressure-lowering treatment on long-term blood pressure: an individual patient-level meta-analysis involving 50 randomised trials and 334,219 participants

Background

Meta-analyses of randomised controlled trials (RCT) have shown the efficacy of pharmacologic lowering of blood pressure (BP) in reducing cardiovascular disease (CVD) risk. While efficacy has been shown across important patient characteristics, meta-analysis based on aggregate data could not fully account for potential sources of variation due to individual-level characteristics. Moreover, it is unclear if any variation in treatment effects due to patient characteristics are reflected in differential effects of BP-lowering treatment on long-term BP according to these characteristics.

Purpose

We determined the effects of BP-lowering treatment on repeated measures of blood pressure, identified trial- and participant-level sources of heterogeneity, and examined consistency of these BP-lowering effects across different patient characteristics.

Methods

We conducted an individual patient-level data meta-analysis (N=50 trials) using one-stage approach. We classified trials according to trial design: drug comparison (N=28), placebo-controlled (N=21) and BP-lowering intensity (N=8) trials. We fitted mixed models with fixed treatment effects and fixed time effect, random intercepts at trial and participant level, and a random slope for time at participant level. We adjusted for age, sex and baseline BP (except when used as stratification factor). We used likelihood ratio test and Akaike information criterion to compare models.

Results

This meta-analysis included 334,219 (42% women) participants. At baseline, mean age=65 (SD=9) years, among whom 18% were current smokers, 47% had cardiovascular disease, 29% had diabetes, and 73% were previously on BP-lowering medication. Participants had an average of 8 BP measurements over 4 years of mean follow-up. For drug comparison trials, mean differences (95% confidence interval) in systolic BP (SBP) and diastolic BP (DBP) between comparison arms were 1.3 (1.2 to 1.3) mmHg and 0.5 (0.5 to 0.5) mmHg, respectively; for placebo-controlled trials, the SBP and DBP differences were 4.2 (4.0 to 4.3) mmHg and 1.9 (1.9 to 2.0) mmHg, respectively; and for BP-lowering intensity trials, the SBP and DBP differences were 8.2 (8.0 to 8.4) mmHg and 3.7 (3.6 to 3.9) mmHg, respectively. However, BP reduction differed by duration of follow-up, type of trial. In particular, for placebo-controlled and BP-intensity trials, heterogeneity in BP reductions according to patient characteristics such as baseline BP, age, sex, prior CVD, diabetes and non-randomised anti-hypertensive use were observed.

Conclusion

This study shows the role of pharmacologic agents in effectively reducing long-term BP across individuals with a wide range of characteristics. The magnitude of BP reduction varied by several patient characteristics. This might have implications for investigation and explanation of any differential effects of BP treatment on major clinical outcomes.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): British Heart Foundation; NIHR Oxford Biomedial Research Centre

Differential proteostatic regulation of insoluble and abundant proteins

Motivation

Despite intense effort, it has been difficult to explain chaperone dependencies of proteins from sequence or structural properties.

Results

We constructed a database collecting all publicly available data of experimental chaperone interaction and dependency data for the Escherichia coli proteome, and enriched it with an extensive set of protein-specific as well as cell-context-dependent proteostatic parameters. Employing this new resource, we performed a comprehensive meta-analysis of the key determinants of chaperone interaction. Our study confirms that GroEL client proteins are biased toward insoluble proteins of low abundance, but for client proteins of the Trigger Factor/DnaK axis, we instead find that cellular parameters such as high protein abundance, translational efficiency and mRNA turnover are key determinants. We experimentally confirmed the finding that chaperone dependence is a function of translation rate and not protein-intrinsic parameters by tuning chaperone dependence of Green Fluorescent Protein (GFP) in E.coli by synonymous mutations only. The juxtaposition of both protein-intrinsic and cell-contextual chaperone triage mechanisms explains how the E.coli proteome achieves combining reliable production of abundant and conserved proteins, while also enabling the evolution of diverging metabolic functions.

Availability and implementation

The database will be made available via http://phdb.switchlab.org.

Supplementary information

Supplementary data are available at Bioinformatics online.

Skeletal abnormalities secondary to antenatal etidronate treatment for suspected generalised arterial calcification of infancy

Background

Generalised arterial calcification of infancy (GACI) is a rare disorder characterised by the deposition of hydroxyapatite crystals within the vessel walls. It is associated with a high mortality rate. Bisphosphonates have been used with some success in the treatment of GACI. However, there is a paucity of data on the antenatal use of bisphosphonates for GACI. In this paper, we report development of the skeletal changes suggestive of hypophosphatasia (HPP) in an infant with GACI, whose mother was treated with etidronate during pregnancy.

Case report

A Caucasian infant boy had a suspected antenatal diagnosis of GACI based on the findings suggestive of calcification of the annulus of the tricuspid valve and wall of the right ventricular (RV) outflow tract and main pulmonary artery on foetal echocardiography and the genetic analysis which showed a pathogenic heterozygous mutation in ABCC6. Based on these findings, mother was started on etidronate treatment from 26 weeks of gestation. A healthy male baby was delivered at 38 weeks of gestation. Initial postnatal echocardiogram on day 1 of life was normal with good biventricular function; subtle changes suggestive of microcalcifications were detected on the CT angiography. Serum calcium, phosphate, alkaline phosphatase and renal profile were normal. Further, the serum inorganic pyrophosphate (PPi) level was significantly low. Skeletal changes suggestive of HPP were seen on the radiographs. The baby developed cardiac dysfunction on day 4 of life with evidence of ischaemic changes on electrocardiogram (ECG).Treatment with etidronate was started in view of probable evolving coronary calcifications. Despite treatment with cardiac supportive measures and bisphosphonate, he succumbed to death in the third week of life.

Discussion

We believe, this is the first report of skeletal changes suggestive of HPP, arising secondary to antenatal etidronate (first generation bisphosphonate) used for the treatment of suspected GACI due to a heterozygous ABCC6 mutation.

Protein Homeostasis Database: protein quality control in E.coli

MOTIVATION

In vivo protein folding is governed by molecular chaperones, that escort proteins from their translational birth to their proteolytic degradation. In E.coli the main classes of chaperones that interact with the nascent chain are trigger factor, DnaK/J and GroEL/ES and several authors have performed whole-genome experiments to construct exhaustive client lists for each of these.

RESULTS

We constructed a database collecting all publicly available data of experimental chaperone-interaction and -dependency data for the E.coli proteome, and enriched it with an extensive set of protein-specific as well as cell context-dependent proteostatic parameters. We made this publicly accessible via a web interface that allows to search for proteins or chaperone client lists, but also to profile user-specified datasets against all the collected parameters. We hope this will accelerate research in this field by quickly identifying differentiating features in datasets.

AVAILABILITY AND IMPLEMENTATION

The Protein Homeostasis Database is freely available without any registration requirement at http://PHDB.switchlab.org/.

Structural Basis of the Subcellular Topology Landscape of Escherichia coli

Cellular proteomes are distributed in multiple compartments: on DNA, ribosomes, on and inside membranes, or they become secreted. Structural properties that allow polypeptides to occupy subcellular niches, particularly to after crossing membranes, remain unclear. We compared intrinsic and extrinsic features in cytoplasmic and secreted polypeptides of the Escherichia coli K-12 proteome. Structural features between the cytoplasmome and secretome are sharply distinct, such that a signal peptide-agnostic machine learning tool distinguishes cytoplasmic from secreted proteins with 95.5% success. Cytoplasmic polypeptides are enriched in aliphatic, aromatic, charged and hydrophobic residues, unique folds and higher early folding propensities. Secretory polypeptides are enriched in polar/small amino acids, β folds, have higher backbone dynamics, higher disorder and contact order and are more often intrinsically disordered. These non-random distributions and experimental evidence imply that evolutionary pressure selected enhanced secretome flexibility, slow folding and looser structures, placing the secretome in a distinct protein class. These adaptations protect the secretome from premature folding during its cytoplasmic transit, optimize its lipid bilayer crossing and allowed it to acquire cell envelope specific chemistries. The latter may favor promiscuous multi-ligand binding, sensing of stress and cell envelope structure changes. In conclusion, enhanced flexibility, slow folding, looser structures and unique folds differentiate the secretome from the cytoplasmome. These findings have wide implications on the structural diversity and evolution of modern proteomes and the protein folding problem.

Nondegenerate Solitons in Manakov System

It is known that the Manakov equation which describes wave propagation in two mode optical fibers, photorefractive materials, etc., can admit solitons which allow energy redistribution between the modes on collision that also leads to logical computing. In this Letter, we point out that the Manakov system can admit a more general type of nondegenerate fundamental solitons corresponding to different wave numbers, which undergo collisions without any energy redistribution. The previously known class of solitons which allows energy redistribution among the modes turns out to be a special case corresponding to solitary waves with identical wave numbers in both the modes and traveling with the same velocity. We trace out the reason behind such a possibility and analyze the physical consequences.

Comprehensive subcellular topologies of polypeptides in Streptomyces

Background

Members of the genus Streptomyces are Gram-positive bacteria that are used as important cell factories to produce secondary metabolites and secrete heterologous proteins. They possess some of the largest bacterial genomes and thus proteomes. Understanding their complex proteomes and metabolic regulation will improve any genetic engineering approach.

Results

Here, we performed a comprehensive annotation of the subcellular localization of the proteome of Streptomyces lividans TK24 and developed the Subcellular Topology of Polypeptides in Streptomyces database (SToPSdb) to make this information widely accessible. We first introduced a uniform, improved nomenclature that re-annotated the names of ~ 4000 proteins based on functional and structural information. Then protein localization was assigned de novo using prediction tools and edited by manual curation for 7494 proteins, including information for 183 proteins that resulted from a recent genome re-annotation and are not available in current databases. The S. lividans proteome was also linked with those of other model bacterial strains including Streptomyces coelicolor A3(2) and Escherichia coli K-12, based on protein homology, and can be accessed through an open web interface. Finally, experimental data derived from proteomics experiments have been incorporated and provide validation for protein existence or topology for 579 proteins. Proteomics also reveals proteins released from vesicles that bleb off the membrane. All export systems known in S. lividans are also presented and exported proteins assigned export routes, where known.

Conclusions

SToPSdb provides an updated and comprehensive protein localization annotation resource for S. lividans and other streptomycetes. It forms the basis for future linking to databases containing experimental data of proteomics, genomics and metabolomics studies for this organism.

Electronic supplementary material

The online version of this article (10.1186/s12934-018-0892-0) contains supplementary material, which is available to authorized users.

Aggregating sequences that occur in many proteins constitute weak spots of bacterial proteostasis

Aggregation is a sequence-specific process, nucleated by short aggregation-prone regions (APRs) that can be exploited to induce aggregation of proteins containing the same APR. Here, we find that most APRs are unique within a proteome, but that a small minority of APRs occur in many proteins. When aggregation is nucleated in bacteria by such frequently occurring APRs, it leads to massive and lethal inclusion body formation containing a large number of proteins. Buildup of bacterial resistance against these peptides is slow. In addition, the approach is effective against drug-resistant clinical isolates of Escherichiacoli and Acinetobacterbaumannii, reducing bacterial load in a murine bladder infection model. Our results indicate that redundant APRs are weak points of bacterial protein homeostasis and that targeting these may be an attractive antibacterial strategy.

Aggregation is sequence-specific and nucleated by short aggregating protein segments (APR). Here authors use a multidisciplinary approach to show that in E.coli some frequently occurring APRs lead to protein aggregation and ultimately bacterial cell death, which could serve as antibacterial strategy.

Health-seeking behaviour among patients with faecal incontinence in a Malaysian academic setting

BACKGROUND

Faecal incontinence (FI) is not a common presenting complaint in Malaysia, and little has been published on this topic. Since it is a treatable condition, a greater understanding of factors contributing to healthseeking behaviour is needed in order to plan effective provision of services.

METHODS

A survey of 1000 patients and accompanying relatives, visiting general surgical and obstetrics and gynaecology clinics for matters unrelated to FI, was conducted at University Malaya Medical Centre between January 2009 and February 2010. A follow-up regression analysis of the 83 patients who had FI, to identify factors associated with health-seeking behaviour, was performed. Variables identified through univariate analysis were subjected to multivariate analysis to determine independence. Reasons for not seeking treatment were also analysed.

RESULTS

Only eight patients (9.6%) had sought medical treatment. On univariate analysis, the likelihood of seeking treatment was significantly higher among patients who had more severe symptoms (OR 30.0, p=0.002), had incontinence to liquid stool (OR 3.83, p=0.002) or when there was an alteration to lifestyle (OR: 17.34; p<0.001). Nevertheless, the only independently-associated variable was alteration in lifestyle. Common reasons given for not seeking treatment was that the condition did not affect patients' daily activities (88.0%), "social taboo" (5.3%) and "other" reasons (6.7%).

CONCLUSIONS

Lifestyle alteration is the main driver of healthseeking behaviour in FI. However, the majority do not seek treatment. Greater public and physician-awareness on FI and available treatment options is needed.

Interleukin 4 induces apoptosis of acute myeloid leukemia cells in a Stat6-dependent manner

Cytokines provide signals that regulate immature normal and acute myeloid leukemia (AML) cells in the bone marrow microenvironment. We here identify interleukin 4 (IL4) as a selective inhibitor of AML cell growth and survival in a cytokine screen using fluorescently labeled AML cells. RNA-sequencing of the AML cells revealed an IL4-induced upregulation of Stat6 target genes and enrichment of apoptosis-related gene expression signatures. Consistent with these findings, we found that IL4 stimulation of AML cells induced Stat6 phosphorylation and that disruption of Stat6 using CRISPR/Cas9-genetic engineering rendered cells partially resistant to IL4-induced apoptosis. To evaluate whether IL4 inhibits AML cells in vivo, we expressed IL4 ectopically in AML cells transplanted into mice and also injected IL4 into leukemic mice; both strategies resulted in the suppression of the leukemia cell burden and increased survival. Notably, IL4 exposure caused reduced growth and survival of primary AML CD34⁺CD38^- patient cells from several genetic subtypes of AML, whereas normal stem and progenitor cells were less affected. The IL4-induced apoptosis of AML cells was linked to Caspase-3 activation. Our results demonstrate that IL4 selectively induces apoptosis of AML cells in a Stat6-dependent manner-findings that may translate into new therapeutic opportunities in AML.

Prevalence and antibacterial resistance patterns of extended-spectrum beta-lactamase producing Gram-negative bacteria isolated from ocular infections

Purpose:

Extended-spectrum beta-lactamases (ESBLs) mediated resistance is more prevalent worldwide, especially among Gram-negative bacterial isolates, conferring resistance to the expanded spectrum cephalosporins. As limited data were available on the prevalence of ESBLs in this area, the current study was undertaken to determine the prevalence, antibacterial resistance patterns, and molecular detection and characterization of ESBL encoding resistance genes among ocular Gram-negative bacterial isolates from ocular infections.

Materials and Methods:

A prospective study was done on 252 ocular Gram-negative bacterial isolates recovered from ocular infections during a study period from February 2011 to January 2014. All isolates were subjected to detection of ESBLs by cephalosporin/clavulanate combination disc test and their antibacterial resistance pattern was studied. Molecular detection and characterization of ESBL encoding bla_TEM-, bla_SHV, bla_OXA-, and bla_CTX-M (phylogenetic groups 1, 2, 9, and 8/25) resistance genes by multiplex polymerase chain reaction and DNA sequence analysis.

Results:

Of all Gram-negative bacteria, Pseudomonas aeruginosa (44%) was the most common strain, followed by Enterobacter agglomerans and Klebsiella pneumoniae each (10%). Among the 252, 42 (17%) were ESBL producers. The major source of ESBL producers were corneal scraping specimens, highest ESBL production was observed in P. aeruginosa 16 (38%) and Escherichia coli 7 (16.6%). Among ESBL-producing genes, the prevalence of bla_TEM-gene was the highest (83%) followed by bla_OXA-gene (35%), bla_SHV-gene (18.5%), and bla_CTX-M-1-gene (18.5%) alone or together.

Conclusion:

The higher rate of prevalence of ESBLs-encoding genes among ocular Gram-negative bacteria is of great concern, as it causes limitation to therapeutic options. This regional knowledge will help in guiding appropriate antibiotic use which is highly warranted.

Clinical and genetic characterization of a large primary open angle glaucoma pedigree

PURPOSE

To both characterize the clinical features of large primary open angle glaucoma (POAG) pedigree from a village in southern India and to investigate the genetic basis of their disease.

MATERIALS AND METHODS

Eighty-four members of a large pedigree received complete eye examinations including slit lamp examination, tonometry, gonioscopy, and ophthalmoscopy. Some were further studied with perimetry. Those diagnosed with POAG were tested for disease-causing mutations in the myocilin and optineurin genes with Sanger sequencing.

RESULTS

Fourteen of 84 family members were diagnosed with POAG, while eight were clinically judged to be POAG-suspects. The family structure and the pattern of glaucoma in the pedigree are complex. Features of glaucoma in this pedigree include relatively early age at diagnosis (mean 50 ± 14 years) and maximum intraocular pressures ranging from 14 to 36 mm Hg with a mean of 23 mm Hg ± 6.5 mm Hg. Patients had an average central corneal thickness (mean 529 ± 37.8 microns) and moderate cup-to-disc ratios (0.74 ± 0.14). No mutations were detected in myocilin, optineurin, or TANK binding kinase 1 (TBK1).

CONCLUSIONS

We report a five-generation pedigree with a complex pattern of POAG inheritance that includes 22 POAG patients and glaucoma suspects. Although the familial clustering of POAG in this pedigree is consistent with dominant inheritance of a glaucoma-causing gene, mutations were not detected in genes previously associated with autosomal dominant glaucoma, suggesting the involvement of a novel disease-causing gene in this pedigree.

An Experimental Analysis of the Catecholamines in Hyperglycemia and Acidosis-Induced Rat Brain

Hyperglycemia and acidosis are the hallmarks of diabetes. Since these factors play an important role in diabetic complications, we have studied the brain catecholamine levels in hyperglycemic and acidotic conditions per se. Experimentally induced hyperglycemia and acidosis are accompanied by significant alterations in the catecholamine levels in discrete areas of the brain. We and others have shown that chronic or acute diabetes in animals, as well as in humans results in altered neurotransmitter levels. In the present study, hyperglycemia maintained by daily external administration of glucose for thirty days showed increased level of dopamine in striatum and hippocampus, elevation of norepinephrine in hippocampus, and increased level of epinephrine in hypothalamus, midbrain and pons medulla. The ammonium chloride induced acidosis demonstrated significant elevation of dopamine in midbrain and significant increase of norepinephrine in hypothalamus and midbrain, and increased level of epinephrine in hypothalamus, pons medulla and cerebral cortex. On the other hand, sodium acetoacetate induced acidosis did not show any significant change in the level of catecholamines in any of the areas studied. In conclusion, the changes in catecholamine levels observed in experimentally induced hyperglycemic as well as in acidotic conditions are closely related to the changes observed in spontaneous or alloxan or streptozotocin diabetic animals, thereby suggesting that these conditions may be responsible for the changes observed in diabetic animals.

Abstract P2-12-20: Rapid evaporative ionisation mass spectrometry towards real time intraoperative oncological margin status determination in breast conserving surgery

Introduction: Positive tumour margins following attempted breast conserving surgery (BCS) is an important risk factor for local recurrence. Nationally in the United Kingdom on average approximately 25% of patients undergoing BCS require additional surgery for positive margins. Traditional techniques such as specimen xray, frozen section & imprint cytology to optimise margin clearance have significant limitations. Various research methods under investigation include optical spectroscopy, high resolution imaging and radiofrequency spectroscopy. Rapid Evaporative Ionisation Mass Spectrometry (REIMS) is a new method that uses mass spectrometric analysis of the tissue specific ionic content of the surgical diathermy smoke plume for the rapid identification of dissected breast tissues as an intelligent knife (iKnife). We investigate the ability of the "iKnife" to analyze heterogeneous breast tissue intraoperatively using mass spectrometric techniques.

Method: The study involved three stages that comprised: method development, tissue specific ex-vivo database construction and intraoperative analysis. Smoke aerosol produced as a result of electrosurgical diathermy from a variety of frozen, fresh and in-vivo breast samples were aspirated into a mass spectrometer via a modified surgical handpiece. Tissue diagnosis was confirmed by subsequent histopathological validation. The data underwent computational analysis using multivariate statistics –predominantly Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA), along with leave one patient out cross-validation. A total of 128 patients (n=40 method development, n=66 ex-vivo database, n=22 intraoperative analysis) undergoing breast surgery were enrolled in this study. Ethical approval was obtained from the Research Ethics Committee.

Results: 40 patients contributed breast samples (normal and cancerous) for method optimisation to enable analysis of high intensity spectra from heterogeneous breast tissue. Following optimisation an ex-vivo database was constructed from 89 excised fresh breast tissue samples from 66 patients using 330 spectra (246 Normal, 60 Tumour – IDC, ILC, IMC and 24 Benign - fibroadenoma). Multivariate statistical analysis of data revealed classification of tumour compared to normal tissue with sensitivities of 93.0% and specificity of 91.9%. The iKnife was used intraoperatively during the entire operation of 25 surgeries. Spectral data was obtained within 1-2 seconds. Specific margin analysis correctly identified negative margins in 10 cases.

Conclusions: The iKnife has been successfully developed for analysis of intraoperative heterogeneous breast tissue. Preliminary data suggests that this technique is suitable with high accuracy for the separation of normal, benign (fibroadenoma) and cancerous (invasive ductal and invasive lobular carcinoma) breast tissues. In comparison to the normal breast, cancerous tissues exhibit statistically different spectral profiles. Further work is aimed at the development of a real time algorithm able to match intraoperative data with the pre-existing database for the rapid interpretation and real time feedback of intraoperative data towards detecting positive margins intraoperatively.

Citation Format: St John ER, Al-Khudairi R, Balog J, Rossi M, Gildea L, Speller A, Ramakrishnan R, Shousha S, Takats Z, Leff DR, Darzi A. Rapid evaporative ionisation mass spectrometry towards real time intraoperative oncological margin status determination in breast conserving surgery. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-12-20.

Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products

Cellulose pulp has a visible market share in personal hygiene products such as sanitary napkins and baby diapers. However it offers good surface for growth of microorganisms. Huge amount of research is going on in developing hygiene products that do not initiate microbial growth. The objective of the present work is to produce antibacterial cellulose pulp by depositing silver nanopowder on the cellulose fiber. The silver nanoparticles used were of less than 100 nm in size and were characterised using transmission electron microscopy and X-ray powder diffraction studies. Antibacterial activity of the functionalized cellulose pulp was proved by JIS L 1902 method. The in-vitro cytotoxicity, in-vivo vaginal irritation and intracutaneous reactivity studies were done with silver nanopowder incorporated cellulose pulp for introducing a new value added product to the market. Cytotoxicity evaluation suggested that the silver nanoparticle incorporated cellulose pulp is non-cytotoxic. No irritation and skin sensitization were identified in animals tested with specific extracts prepared from the test material in the in-vivo experiments. The results indicated that the silver nanopowder incorporated cellulose pulp meets the requirements of the standard practices recommended for evaluating the biological reactivity and has good biocompatibility, hence can be classified as a safe hygiene product.

Controlled release of copper from an intrauterine device using a biodegradable polymer

BACKGROUND

The adverse effects of copper intrauterine devices (IUDs) such as abnormal bleeding, pain and cramps may be due in part to the burst release of copper ions during the first few months of usage. This study focuses on controlling the initial burst release of copper ions.

STUDY DESIGN

This study evaluated in vitro release rates of copper for a period of 1 year from standard CuT380 IUDs (n=6) and from CuT380 IUDs coated with poly(dl-lactide-co-glycolide) (PLGA) films (n=6). This study characterized the coated device for its morphological changes during degradation of film by scanning electron microscopy (SEM).

RESULTS

CuT380 IUDs coated with PLGA film with a thickness of 0.10±0.02 mm showed a reduced initial copper release (40-80 mcg/day) compared with uncoated CuT380 IUDs (150-200 mcg/day). Statistically significant (p<.05) results were obtained at different time intervals during the overall study period of 1 year. SEM images showed degradation of coating.

CONCLUSION

Coating a CuT380 IUD with biodegradable polymer reduced the initial copper release without affecting release at 1 year. Clinical trials are required to determine whether this could reduce side effects such as bleeding and pain associated with copper containing IUDs.

Open angle glaucoma in a case of Type IV Ehler Danlos syndrome: a rarely reported association

A 26-year-old male presented to us with defective vision in the left eye. He had best corrected visual acuity (BCVA) of hand movement (HM) in right eye and 6/9 in left eye. He had ptosis with ectropion in both eyes and relative afferent pupillary defect (RAPD) in right eye. Intraocular pressure (IOP) was 46 and 44 mmHg in right and left eye, respectively. Fundus showed glaucomatous optic atrophy (GOA) in right eye and cup disc ratio (CDR) of 0.75 with bipolar rim thinning in left eye. Systemic examination showed hyperextensible skin and joints, acrogeria, hypodontia, high arched palate, and varicose veins. He gave history of easy bruising and tendency to fall and history of intestinal rupture 5 years ago for which he had undergone surgery. He was diagnosed as a case of Type IV Ehler-Danlos syndrome (EDS) with open angle glaucoma. He underwent trabeculectomy in both eyes. This is a rare case that shows glaucoma in a patient of EDS Type IV. Very few such cases have been reported in literature.

Anterior segment optical coherence tomography documentation of a case of topiramate induced acute angle closure

We present a case report of a 31-year-old female patient who presented to us with a 1 day history of acute bilateral eye pain, blurred vision and headache. She was found to have a myopic shift, raised intraocular pressure (IOP) and shallow anterior chambers in both eyes. She had been commenced on oral topiramate 1 week previously. A number of investigations, including anterior segment optical coherence tomography (AS-OCT) were done and a diagnosis of topiramate induced bilateral acute angle closure (TiAAC) was made. Topiramate was discontinued and she was managed with topical and oral antiglaucoma medications, topical steroids and cyclopegics. Her symptoms subsided dramatically at the next follow-up. The AS-OCT documentation revealed lucidly the improvement in her anterior chamber depth and anterior chamber angle parameters. Her IOP decreased, her myopic shift showed reversal and her AS-OCT findings revealed gross improvement in all the parameters angle opening distance, trabecular iris space area and scleral spur angle. This case report clearly shows with AS OCT documentation the changes which occur in the anterior segment in a case of TiAAC.

The shift from public to private health care providers and malaria deaths in Jalpaiguri district, West Bengal, India, 2006

We investigated an increase in malaria deaths in order to formulate control measures. A search of records in health care facilities for cases of death following fever, with a blood smear or rapid antigen test positive for Plasmodium falciparum, identified 77 fatalities. Of these, 72 (93%) occurred in hospitals (78% of which in the 24 hours following admission). Of 60 family members of the patients who died interviewed, 70% reported that the patient had received care from unqualified rural private practitioners available round the clock. Among 100 of these rural practitioners assessed, 21% knew anti-malarial dosage and 7% knew malaria severity criteria. There were 65% and 42% vacancies among 240 community health worker and 12 microscopist positions, respectively, in the public sector in the area. As a result, the mean interval between active case search rounds in the community was 35 days (standard: 14) and the median time between blood slide collection and radical treatment was 12 days (standard < 2 days). Deficiencies in the public health system may have led to a shift towards rural practitioners. Poor management of malaria may have contributed to deaths. We posted microscopists and community health workers in the area to restore appropriate malaria management in the public sector.

Vittaforma corneae keratitis in southern India: role of a novel duplex PCR

Microsporidia are obligate intracellular parasites that infect eukaryotic cells and have emerged as major opportunistic human pathogens. Due to the difficulties in definitive laboratory diagnosis and insufficient knowledge, ocular microsporidiosis is infrequently reported in India. To improve diagnostic facilities, we have developed a novel duplex PCR (dPCR) for the simultaneous identification of both genera and species of isolates with microsporidian aetiology that cause keratitis. The material scraped from the corneas of 12 clinically diagnosed microsporidial keratitis patients was subjected to routine microbiological examinations and molecular diagnosis using a novel dPCR that targeted the small-subunit rRNA gene (SSU-rRNA) of microsporidia and Vittaforma corneae using genus- and species-specific primers. Of the 12 corneal scrapes, 6 showed positive results in smears, while dPCR provided positive amplification with both pan-microsporidial and V. corneae species-specific primers for 9 corneal scrapes. The results were validated by sequencing and blast analysis. The sensitivity of this novel dPCR method was higher than that of conventional microscopy in the diagnosis of corneal microsporidial infection. dPCR with specific primers is potentially more sensitive, specific and depends less on more complicated methods for exact identification of the aetiology of microsporidial keratitis.

A study of initial therapy for glaucoma in southern India: India Glaucoma Outcomes and Treatment (INGOT) Study

PURPOSE

To compare initial glaucoma therapy with medications and trabeculectomy in southern India.

METHODS

Patients aged ≥ 30 years newly diagnosed with glaucoma were randomized to trabeculectomy with 5-fluorouracil or medical therapy. Subjects with best-corrected vision <6/18 due to cataract underwent phacoemulsification (phaco/intraocular lens, IOL). Intraocular pressure (IOP), vision and visual function were assessed at 12 months.

RESULTS

Patients assigned to medications and surgery received the expected therapy in 86% (172/199) and 64% (126/199) of cases, respectively. Forty patients (20%) assigned to surgery refused any treatment and 33 (17%) received medications. Among 199 patients randomized to medications, 52 (26.1%) underwent phaco/IOL, as did 89/199 (43.7%) of patients randomized to trabeculectomy. Baseline parameters of the two groups did not differ, nor did 1-year follow-up rates (medication 65%, trabeculectomy 58%, P = 0.15). Final IOP was lower with randomization to trabeculectomy (16.3 ± 5.1 mmHg) than medication (18.8 ± 6.7 mmHg, P < 0.0001). In regression models, randomization to trabeculectomy (P < 0.0001) was associated with lower IOP, and simultaneous trabeculectomy and cataract surgery was associated with higher IOP (P = 0.008) than trabeculectomy alone. Subjects receiving Phaco/IOL had significantly better final acuity (P < 0.0001) and visual function (P = 0.035), despite concurrent glaucoma treatment. Final visual acuity was worse in those receiving trabeculectomy in addition to cataract surgery, but this was of borderline significance (P = 0.06).

CONCLUSIONS

Trabeculectomy lowered IOP significantly more than medical treatment, but with slightly greater loss of visual acuity. Combined phaco/IOL and trabeculectomy improved visual acuity with substantial IOP lowering.