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.

The efficacy of different irrigation protocols in removing tricalcium silicate-based sealers from simulated root canal irregularities

OBJECTIVE

The aim of this study was to evaluate the efficacy of different irrigation protocols in removing two tricalcium silicate-based sealers from simulated root canal irregularities and root canal walls.

MATERIAL AND METHODS

Root canals of 140 single-rooted teeth were instrumented. In one-half of each root, an apical groove was created. The samples were divided into two main groups (n = 70) based on the sealer used. In group 1, the grooves were filled with MTA Fillapex; in group 2, BioRoot RCS. The reassembled root halves were divided into six experimental and one control groups: 2.5% NaOCl-17% EDTA (Passive ultrasonic irrigation [PUI]), 5% NaOCl/9% DualRinse HEDP (PUI), 2.5% NaOCl-7% Maleic acid (PUI), 2.5% NaOCl-17% EDTA (Er:YAG laser activated irrigation [LAI]), 2.5% NaOCl/9% DualRinse HEDP (LAI), 2.5% NaOCl-7% Maleic acid (LAI), Distilled water (Control). Specimens were scored using SEM. The data were analysed using Kruskal-Wallis and Mann Whitney U tests.

RESULTS

Maleic acid and DualRinse HEDP removed higher amounts of MTA Fillapex from the grooves compared to EDTA, when used with both activation methods (p < .001).

CONCLUSIONS

Ultrasonically activated maleic acid or DualRinse HEDP can be an effective irrigation regimen in removing tricalcium silicate-based sealers.

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.