0057 Actigraphy-Based Circadian Measures and Cerebrospinal Fluid Biomarkers of Neurodegeneration in Alzheimer’s Disease with Mild Cognitive Impairment

Introduction

Although recent data implicates sleep and circadian disruption to neurodegeneration in Alzheimer’s Disease (AD), the association of objective circadian biomarkers and neurodegeneration remains understudied. We hypothesize that actigraphy-based circadian measures are associated with cerebrospinal fluid (CSF) biomarkers of neurodegeneration in those mild cognitive impairment due to AD (MCI-AD).

Methods

Eighteen patients with CSF biomarker-confirmed MCI-AD underwent actigraphy monitoring generating the following circadian measures: amplitude, F-ratio and mesor and morning collection of CSF biomarkers of neurodegeneration (Aβ42,t-tau,p-tau). Linear models were used to evaluate the association of circadian and CSF measures; logarithmic transformations were performed on neurodegenerative markers for greater normality. Analysis was performed using SAS software. A significance level of 0.05 was assumed for all tests.

Results

Eighteen MCI-AD patients who were 68± 6.2 years, 44% female, with median AHI=12 and underwent actigraphy monitoring for 8.2+/-3.2 days were included. There was no significant association of circadian measures and Aβ42 nor with mesor and neurodegeneration biomarkers. Amplitude was associated with both p-tau and t-tau, such that each 10 unit increase in amplitude resulted in a predicted increase in p-tau of 8% (95% CI:1%-15%, p=0.018) and an increase of 13% (3%-23%; p=0.01) in t-tau. F-ratio was positively associated with p-tau and t-tau; each 1000 unit increase in F-ratio resulted in a predicted 12% (4%-22%; p=0.007) increase in P-tau and 20%(6%-35%; p=0.005) increase in t-tau. Associations of these circadian measures and CSF levels of p-tau and t-tau remained statistically significant after adjustment for age and sex.

Conclusion

Among patients with symptomatic MCI stages of AD, objective measures of circadian rhythm disruption are associated with CSF-based biomarkers of neurodegeneration even after consideration of age and sex. Future investigation should clarify directionality of this association and potential utility of circadian-based interventions in the mitigation of AD progression.

Support

N/A

Neonatal outcomes following previable prelabour rupture of membranes before 23 weeks of gestation - A retrospective cohort study

OBJECTIVE

To compare outcomes of hospitalized preterm infants following previable prelabour rupture of membranes (PPROM) at≤23 weeks of gestation.

METHODS

Retrospective cohort study of preterm infants admitted for intensive care, between January 2006 and December 2016 following PPROM, was conducted. Short term clinical outcomes included severity of respiratory morbidity, length of hospital stay and mortality. Neurodevelopment in survivors was assessed using Bayley's Scales of Infant Development (3rd edition) at 24 months corrected age.

RESULTS

A total of 82 preterm infants were admitted following PPROM at < 23 weeks and were grouped as: Group 1 (n = 28) with PPROM < 20 weeks and Group 2 (n = 54) with PPROM between 20-22 + 6 weeks. Median latency following PPROM was significantly longer in Group 1 infants [69(Interquartile range (IQR): 43-74; Range (R): 25-100 vs. 29(IQR: 10-53; R: 2-72) days, p < 0.001]. Median gestation at delivery was 27.4 weeks (Group 1) vs. 25.1 weeks (Group 2). Group 1 had a significantly higher incidence of oligohydramnios [13(46.4%) vs. 8(14.8%), p = 0.002], lower Apgar scores (<7) at 5 minutes [19(67.9%) vs. 24(44.4%), p = 0.044], increased pulmonary hypoplasia [13(46.4%) vs. 5(9.3%), p < 0.001], joint contractures [3(10.7%) vs. 0, p = 0.037] and mortality [10(35.7%) vs. 7(13.0%), p = 0.016]. Neurodevelopmental outcomes at 24 months corrected age were comparable in the 36 surviving infants (9/18 vs. 27/547).

CONCLUSION

Morbidity and mortality is high in infants born after previable PPROM; specifically, in those with PPROM < 20 weeks although early childhood neurodevelopmental outcomes were comparable. Larger prospective studies focussing on long term neonatal outcomes are needed to confirm these findings.

The cost-effectiveness of progesterone in preventing miscarriages in women with early pregnancy bleeding: an economic evaluation based on the PRISM trial

OBJECTIVES

To assess the cost-effectiveness of progesterone compared with placebo in preventing pregnancy loss in women with early pregnancy vaginal bleeding.

DESIGN

Economic evaluation alongside a large multi-centre randomised placebo-controlled trial.

SETTING

Forty-eight UK NHS early pregnancy units.

POPULATION

Four thousand one hundred and fifty-three women aged 16-39 years with bleeding in early pregnancy and ultrasound evidence of an intrauterine sac.

METHODS

An incremental cost-effectiveness analysis was performed from National Health Service (NHS) and NHS and Personal Social Services perspectives. Subgroup analyses were carried out on women with one or more and three or more previous miscarriages.

MAIN OUTCOME MEASURES

Cost per additional live birth at ≥34 weeks of gestation.

RESULTS

Progesterone intervention led to an effect difference of 0.022 (95% CI -0.004 to 0.050) in the trial. The mean cost per woman in the progesterone group was £76 (95% CI -£559 to £711) more than the mean cost in the placebo group. The incremental cost-effectiveness ratio for progesterone compared with placebo was £3305 per additional live birth. For women with at least one previous miscarriage, progesterone was more effective than placebo with an effect difference of 0.055 (95% CI 0.014-0.096) and this was associated with a cost saving of £322 (95% CI -£1318 to £673).

CONCLUSIONS

The results suggest that progesterone is associated with a small positive impact and a small additional cost. Both subgroup analyses were more favourable, especially for women who had one or more previous miscarriages. Given available evidence, progesterone is likely to be a cost-effective intervention, particularly for women with previous miscarriage(s).

TWEETABLE ABSTRACT

Progesterone treatment is likely to be cost-effective in women with early pregnancy bleeding and a history of miscarriage.

Early clinical exposure through a vertical integration programme in physiology

Background

Early clinical exposure is likely to be beneficial during the preclinical year. This pilot programme aimed to define a learning framework of introducing first year medical students to early clinical exposure through a vertical integration programme in the physiology course. The intent was to enhance the understanding of theoretical concepts and practical applications of physiology. Student and faculty perceptions were evaluated.

Methods

First year MBBS students (n = 60) had bedside clinics conducted by 5 clinical departments, where the clinical context and applied physiological concepts were emphasized. Clinical sessions were synchronized with pedagogic highlights on related physiological concepts. The student's perceptions were recorded through a semi-structured questionnaire, while qualitative feedback was obtained from the faculty.

Results

All students ( 100%) reported that the programme was relevant and did not interfere with their physiology course. Most (91%) appreciated the synchronization of classroom knowledge with clinical exposures, and thought that integrated teaching helped in better understanding of practical applications of physiology (94%) with adequate discussions during the sessions (91 %). Fifty-nine (98%) students preferred integrated teaching over the isolated traditional classroom teaching. The clinicians involved also felt that the early clinical exposure was relevant. The students achieved a mean (SD) score of 13 (2.98) of 25 in the quiz consisting of multiple-choice questions that attempted to test their learning through early clinical exposures.

Conclusion

This pilot exercise showed the utility of early clinical exposure integrated into the physiology course. It will be worthwhile to replicate this exercise at other institutions and among a larger student strength.

P1460Seismocardiographic measurement of systolic time intervals in left ventricular dysfunction: validation with transthoracic echo

Background

Systolic time intervals (STI) measured using Transthoracic Echo (TTE) have been shown to be sensitive indicators of contractile performance, but TTE is limited to a hospital setting. Recent advances in technology have enabled the simultaneous measurement of Electrocardiograms (ECG) and Seismocardiograms (SCG) using wearable devices. However, the use SCG to measure STIs has not been validated in a mobile setting, or on pathological subjects.

Purpose

To test the validity of an automated algorithm for measuring STIs using a wearable device recording ECG and SCG, in subjects with varying degrees of left ventricular dysfunction.

Methods

179 Patients with suspected left ventricular dysfunction were assessed using TTE performed by a Cardiologist. Patients were simultaneously fitted with a novel wearable device worn on a chest strap, recording SCG and single-lead ECG data, while the cardiologist measured the pre-ejection period (PEP) and left ventricular ejection time (LVET) with the patient in a supine position. Of these subjects 29 (16.2%) were diagnosed with Dilated cardiomyopathy (DCM), and 109 (60.8%) had Ischemic Heart disease.

The SCG and ECG data recorded on the wearable device was then analysed using a peak-detection algorithm, which detected the Q,R,S points on the ECG, and then determined the 4 most prominent peaks in the SCG signal corresponding to each R-peak. Heart rate, patient's age, gender and SCG time intervals were then used in a DecisionTree algorithm to determine the values of PEP and LVET, which were were then compared against those determined by the cardiologist using TTE.

Results

The correlation coefficient (r2) between PEP calculated using TTE, and the values obtained from the algorithm analyzing SCG data was 0.92 while the mean error was 7.47%. The r2 between the LVET calculated using the TTE and the algorithm was 0.75, while the mean error was 8.53% (p-value<0.001 for all cases).

Results All Subjects With IHD Without IHD With DCM Without DCM Number of Subjects 178 109 69 29 149 PEP (r2) 0.92 0.89 0.94 0.88 0.91 PEP (% age error) 7.47 7.50 7.42 6.99 7.56 LVET (r2) 0.75 0.81 0.66 0.55 0.83 LVET (% age error) 8.53 6.69 11.4 20.42 6.16 DCM, Dilate Cardiomyopathy; IHD, Ischemic Heart Disease.

ECG + SCG signals for a DCM patient

Conclusion

The algorithm-derived STIs measured by SCG correlate well with those measured by TTE across most patient groups, including those with Dilated Cardiomyopathy and Ischemic Heart Disease, opening prospects for continuous remote monitoring of STIs in a mobile setting.

Acknowledgement/Funding

Fourth Frontier Technologies

P14.94 Mitochondrial DNA copy number in new onset and recurrent glioblastoma and its effect on radiation resistance and patient survival

BACKGROUND

Recent evidence shows that mitochondrial DNA (mtDNA) content is responsible for radiation resistance in various cancers, but not evaluated in glioblastoma(GBM).Hence,we studied the role of mtDNA content in GBM pathogenesis and treatment response.

MATERIAL AND METHODS

Archived FFPE tissues of newly diagnosed GBM(n=130), recurrent GBM (n=32 pairs) and non-neoplastic control brain(n=30) with available clinical details were utilized for the study. Immunohistochemistry, Sanger’s sequencing, methylation specific PCR and fluorescent in-situ hybridization were used to study IDH, ATRX and TERT promoter mutations, MGMT promoter methylation and EGFR amplification. mtDNA content was analyzed using quantitative real time PCR (relative quantification) and was calculated using the formula 2- ΔΔCTx100. Malignant glioma cell lines U87 and LN229 were used to study the difference in mtDNA content following radiation exposure.LN229 cell line was subjected to mtDNA depletion by incubation with ethidium bromide for 4 days.The parent and mtDNA depleted LN229 cell lines were then assessed for sensitivity to radiation and Temozolomide(TMZ) therapy using MTT assay.

RESULTS

mtDNA content was lower than control brain tissue(mean mtDNA content 19.6) in all cases studied,with significantly lower content in older patients(p=0.04).Lower mean mtDNA content was seen in IDH wild type, MGMT unmethylated and EGFR amplified tumors when compared to their counterparts(p=1.06).Survival analysis using Cox regression showed that lower mtDNA copy number is associated with higher risk and hence poorer prognosis(p=0.047).Paired tumor analysis was performed in 32 patients with recurrence of whom only 19 had received radiation therapy (RT).The mean mtDNA content was higher at recurrence as compared to the primary tumor in those who received RT(mean at diagnosis 20.1; mean at recurrence 49.3, p=0.02) while no significant difference was observed in those who did not receive RT. U87 and LN229 cell lines exposed to radiation (0, 2, 4 and 6Gy) showed an increase of 8% and 25% in mtDNA content, respectively, after 6Gy radiation exposure.LN229 parent cells showed a radiation dose dependent decline in cell viability(86% at 2Gy, 68% at 4Gy and 50% at 6Gy).The mtDNA depleted LN229 cells were 100% viable at 0, 2 and 4 Gy and 82% viable at 6Gy.The IC50 of TMZ in parent LN229 cells was 69.3 µM while in the mtDNA depleted cells,it was 100.8 µM. Conclusion:Our study shows that lower mtDNA content is associated with poorer survival in GBM.RT increased the mtDNA content in both patient samples and malignant glioma cell lines.mtDNA depleted LN229 lines are more radio-chemo resistant than parent LN229 lines,thus showing that lower mtDNA content leads to treatment resistance.Hence,we establish the significant role of mtDNA content in the pathogenesis and treatment resistance of GBM.

Evaluation of Smear Layer Removal Using Different Irrigation Methods In Root Canals

This study evaluated different irrigation methods in smear layer removal from the root canal walls using maleic acid (MA). Maxillary anterior teeth (N=30, n=10 per group) were decoronated, canals were enlarged with Protaper (size F4) and allocated to three groups: EndoUltra: 2.5 ml of 7% MA was irrigated for 30 s, followed by EndoUltra activation for 30 s; EndoSafe: EndoSafe irrigation system was used for 1 minute using 5 ml of 7% MA; Side-vented needle: 30 gauge needle irrigation was performed for 1 min using 5 ml of 7% MA. After SEM analysis, the inter-examiner reliability was verified using Kendall's Co-efficient and data were analyzed using Pearson Chi-Square test. No statistical significant differences were found between the two examiners (p⟩0.05). In intra-group comparison, needle and EndoSafe irrigation demonstrated significantly better smear layer removal at middle third of the root canal system (p⟨0.05) when compared to apical third. In inter-group comparison, smear layer was minimally removed with needle irrigation. In the apical third, EndoUltra group removed smear layer more effectively. Endosafe needle irrigation in combination with 7% MA removed the smear layer in the root canal at best, while the EndoUltra performed the best at the apical third of the root.

Pathogenesis and tissue tropism of Newcastle disease virus and avian influenza virus (H9N2) in single and mixed infections

Newcastle disease (ND) and avian influenza (AI) are globally considered as a serious threat to the chicken and other avian species. The paramyxovirus type 1 and orthomyxovirus type A are RNA viruses, which cause ND and AI infection, respectively.