Next generation of multispecific antibody engineering

Multispecific antibodies recognize two or more epitopes located on the same or distinct targets. This added capability through protein design allows these man-made molecules to address unmet medical needs that are no longer possible with single targeting such as with monoclonal antibodies or cytokines alone. However, the approach to the development of these multispecific molecules has been met with numerous road bumps, which suggests that a new workflow for multispecific molecules is required. The investigation of the molecular basis that mediates the successful assembly of the building blocks into non-native quaternary structures will lead to the writing of a playbook for multispecifics. This is a must do if we are to design workflows that we can control and in turn predict success. Here, we reflect on the current state-of-the-art of therapeutic biologics and look at the building blocks, in terms of proteins, and tools that can be used to build the foundations of such a next-generation workflow.

Large library docking for novel SARS-CoV-2 main protease non-covalent and covalent inhibitors

Antiviral therapeutics to treat SARS-CoV-2 are needed to diminish the morbidity of the ongoing COVID-19 pandemic. A well-precedented drug target is the main viral protease (MPro ), which is targeted by an approved drug and by several investigational drugs. Emerging viral resistance has made new inhibitor chemotypes more pressing. Adopting a structure-based approach, we docked 1.2 billion non-covalent lead-like molecules and a new library of 6.5 million electrophiles against the enzyme structure. From these, 29 non-covalent and 11 covalent inhibitors were identified in 37 series, the most potent having an IC50 of 29 and 20 μM, respectively. Several series were optimized, resulting in low micromolar inhibitors. Subsequent crystallography confirmed the docking predicted binding modes and may template further optimization. While the new chemotypes may aid further optimization of MPro inhibitors for SARS-CoV-2, the modest success rate also reveals weaknesses in our approach for challenging targets like MPro versus other targets where it has been more successful, and versus other structure-based techniques against MPro itself.

Effect of remineralizing agent on laser and nonlaser bleached enamel surfaces subjected to erosion: An in vitro study

Aim

Assessment of remineralizing agent's effect on laser and nonlaser bleached enamel surfaces subjected to erosion.

Materials and Methods

In this study, 80 extracted human permanent anteriors were collected and divided into 4 groups with 20 teeth per sample. Enamel specimen of 3 mm × 3 mm were made using polyvinyl chloride rings and acrylic and randomly divided into four groups. Then the specimens were subjected to initial microhardness test using Vicker's hardness tester (AVK-CO, Mitutoyo, Japan). Two indentations were placed at 100 mm from one another in the center of all the samples. Bleaching with laser and without laser using hydrogen peroxide was performed followed by remineralization in the groups (Groups 1a and 2a) and then were subjected to erosion. The final hardness was measured using the above method used for initial microhardness.

Results

Microhardness in the remineralized groups showed least variation. The group in which laser bleaching was performed along with remineralization as compared with nonlaser bleaching group with remineralization showed improvement in microhardness but the data was not statistically significant. A significant difference was noted between the laser and remineralization group when compared with the groups in which no remineralization was done.

Conclusion

After bleaching the enamel surface is more prone to erosion, so to improve the microhardness of bleached enamel a remineralizing agent should be used. A combination of diode laser bleaching and remineralizing agents leads to improved microhardness of the bleached enamel thus proving this combination to be efficacious.

Structure-Based Discovery of Inhibitors of the SARS-CoV-2 Nsp14 N7-Methyltransferase

An under-explored target for SARS-CoV-2 is the S-adenosyl methionine (SAM)-dependent methyltransferase Nsp14, which methylates the N7-guanosine of viral RNA at the 5'-end, allowing the virus to evade host immune response. We sought new Nsp14 inhibitors with three large library docking strategies. First, up to 1.1 billion lead-like molecules were docked against the enzyme's SAM site, leading to three inhibitors with IC50 values from 6 to 50 μM. Second, docking a library of 16 million fragments revealed 9 new inhibitors with IC50 values from 12 to 341 μM. Third, docking a library of 25 million electrophiles to covalently modify Cys387 revealed 7 inhibitors with IC50 values from 3.5 to 39 μM. Overall, 32 inhibitors encompassing 11 chemotypes had IC50 values < 50 μM and 5 inhibitors in 4 chemotypes had IC50 values < 10 μM. These molecules are among the first non-SAM-like inhibitors of Nsp14, providing starting points for future optimization.

Structure-based discovery of conformationally selective inhibitors of the serotonin transporter

The serotonin transporter (SERT) removes synaptic serotonin and is the target of anti-depressant drugs. SERT adopts three conformations: outward-open, occluded, and inward-open. All known inhibitors target the outward-open state except ibogaine, which has unusual anti-depressant and substance-withdrawal effects, and stabilizes the inward-open conformation. Unfortunately, ibogaine's promiscuity and cardiotoxicity limit the understanding of inward-open state ligands. We docked over 200 million small molecules against the inward-open state of the SERT. Thirty-six top-ranking compounds were synthesized, and thirteen inhibited; further structure-based optimization led to the selection of two potent (low nanomolar) inhibitors. These stabilized an outward-closed state of the SERT with little activity against common off-targets. A cryo-EM structure of one of these bound to the SERT confirmed the predicted geometry. In mouse behavioral assays, both compounds had anxiolytic- and anti-depressant-like activity, with potencies up to 200-fold better than fluoxetine (Prozac), and one substantially reversed morphine withdrawal effects.

Measurement of the ν_{e}-Nucleus Charged-Current Double-Differential Cross Section at ⟨E_{ν}⟩=2.4 GeV Using NOvA

The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×10^{20} protons-on-target in the NuMI beam. The sample of GeV electron neutrino interactions is the largest analyzed to date and is limited by ≃17% systematic rather than the ≃7.4% statistical uncertainties. The double-differential cross section in final-state electron energy and angle is presented for the first time, together with the single-differential dependence on Q^{2} (squared four-momentum transfer) and energy, in the range 1  GeV≤E_{ν}<6  GeV. Detailed comparisons are made to the predictions of the GENIE, GiBUU, NEUT, and NuWro neutrino event generators. The data do not strongly favor a model over the others consistently across all three cross sections measured, though some models have especially good or poor agreement in the single differential cross section vs Q^{2}.

On Comparison of Heat Treated and Non-Heat-Treated LOM Manufactured Sample for Poly(lactic)acid: Mechanical and Morphological View Point

This work reports the comparison of heat-treated and non-heat-treated laminated object-manufactured (LOM) 3D-printed specimens from mechanical and morphological viewpoints. The study suggests that heat treatment of the FDM-printed specimen may have a significant impact on the material characteristics of the polymer. The work has been performed at two stages for the characterization of (a) non-heat-treated samples and (b) heat-treated samples. The results for stage 1 (non-heat-treated samples) suggest that the infill density: 70%, infill pattern: honeycomb, and six number of discs in a single LOM-manufactured sample is the optimized condition with a compression strength of 42.47 MPa. The heat treatment analysis at stage 2 suggests that a high temperature: 65 °C, low time interval: 10 min, works equally well as the low temperature: 55 °C, high time interval: 30 min. The post-heat treatment near Tg (65 °C) for a time interval of 10 min improved the compressive strength by 105.42%.

On Laminated Object Manufactured FDM-Printed ABS/TPU Multimaterial Specimens: An Insight into Mechanical and Morphological Characteristics

Fused deposition modeling (FDM) printing of commercial and reinforced filaments is a proven and well-explored method for the enhancement of mechanical properties. However, little has hitherto been reported on the multi-material components, fused or laminated together into a single specimen by using the laminated object manufacturing (LOM) technique for sustainable/renewable polymers. TPU is one such durable and flexible, sustainable material exhibiting renewable and biocompatible properties that have been explored very less often in combination with the ABS polymer matrix in a single specimen, such as the LOM specimen. The current research work presents the LOM manufacturing of 3D-printed flexural specimens of two different, widely used polymers available viz. ABS and TPU and tested as per ASTM D790 standards. The specimens were made and laminated in three layers. They were grouped into two categories, namely ABS: TPU: ABS (ATA) and TPU: ABS: TPU (TAT), which are functionally graded, sandwiched structures of polymeric material. The investigation of the flexural properties, microscopic imaging, and porosity characteristics of the specimens was made for the above categories. The results of the study suggest that ATA-based samples held larger flexural strength than TAT laminated manufactured samples. A significant improvement in the peak elongation and break elongation of the samples was achieved and has shown a 187% increase in the break elongation. Similarly, for the TAT-based specimen, flexural strength was improved significantly from approximately 6.8 MPa to 13 MPa, which represents a nearly 92% increase in the flexural strength. The morphological testing using Tool Maker’s microscopic analysis and porosity analysis has supported the observed trends of mechanical behavior of ATA and TAT samples.

Autoantibody mimicry of hormone action at the thyrotropin receptor

Thyroid hormones are vital in metabolism, growth and development1. Thyroid hormone synthesis is controlled by thyrotropin (TSH), which acts at the thyrotropin receptor (TSHR)2. In patients with Graves' disease, autoantibodies that activate the TSHR pathologically increase thyroid hormone activity3. How autoantibodies mimic thyrotropin function remains unclear. Here we determined cryo-electron microscopy structures of active and inactive TSHR. In inactive TSHR, the extracellular domain lies close to the membrane bilayer. Thyrotropin selects an upright orientation of the extracellular domain owing to steric clashes between a conserved hormone glycan and the membrane bilayer. An activating autoantibody from a patient with Graves' disease selects a similar upright orientation of the extracellular domain. Reorientation of the extracellular domain transduces a conformational change in the seven-transmembrane-segment domain via a conserved hinge domain, a tethered peptide agonist and a phospholipid that binds within the seven-transmembrane-segment domain. Rotation of the TSHR extracellular domain relative to the membrane bilayer is sufficient for receptor activation, revealing a shared mechanism for other glycoprotein hormone receptors that may also extend to other G-protein-coupled receptors with large extracellular domains.

Pulmonary rehabilitation: A novel adjunct in management of obstructive sleep apnea

Pulmonary rehabilitation (PR) is being used in the routine management of patients of obstructive sleep apnea (OSA) at some centers. However, the studies documenting benefits of PR in OSA lack standardization in terms of outcome measures. A study was hence planned to determine the efficacy of PR on exercise capacity, health related quality of life (HRQOL), day time sleepiness and sleep-quality of life (QOL) in patients of OSA. As a part of comprehensive therapy, patients diagnosed with OSA are managed with continuous positive airway pressure (CPAP), 8 weeks thrice weekly outpatient hospital-based PR and medical treatment at the Pulmonary Medicine Department, Government Medical College and Hospital, Chandigarh. However, some patients refuse for PR because of time constraints and travel issues. Patients with newly diagnosed OSA without co-existing respiratory disease, who agreed for the CPAP, PR and medical management were enrolled in group A. The patients who refused for PR but were ready for CPAP and medical management were enrolled in Group B; 30 patients were taken in each group. Exercise capacity, HRQOL, day time sleepiness and sleep-QOL were determined at baseline and at 8-weeks follow-up by 6-minute walk distance (6MWD), St. George's Respiratory Questionnaire (SGRQ), Epworth Sleepiness Scale (ESS) and Functional Outcomes of Sleep Questionnaire (FOSQ) and compared amongst the two groups. Four patients from group A were excluded as they did not complete PR; 26 patients from group A and 30 patients from group B were finally analyzed. At baseline, both groups were matched with respect to age, gender, apnea-hypopnea index (AHI), body mass index (BMI), FEV1%predicted, 6MWD, SGRQ, ESS and FOSQ. At follow up at 8 weeks, BMI, 6MWD, SGRQ, ESS and FOSQ improved significantly from baseline in group A (p<0.001). FEV1%predicted also improved but non significantly. In group B, FEV1%predicted, BMI, 6MWD, SGRQ, ESS and FOSQ score did not improve significantly from baseline. Mean improvement from baseline in BMI, 6MWD, SGRQ, ESS and FOSQ was significantly more in group A than group B (p<0.001, p<0.001, p=0.041, p<0.001 and p<0.001, respectively). PR, being beneficial, should be incorporated in standard management of OSA.

Spectroscopic, electronic structure, molecular docking, and molecular dynamics simulation study of 7-Trifluoromethyl-1H-indole-2-carboxylic acid as an aromatase inhibitor

The present work encompasses a combined experimental and theoretical investigation of the molecular structure, vibrational wavenumbers, electronic structure at the ground and electronic excited states, molecular electrostatic potential surface of 7-(Trifluoromethyl)-1H-indole-2-carboxylic acid (TICA) and possibility of the title molecule as an aromatase inhibitor using molecular docking and molecular dynamic simulations. A stable conformer has been obtained using potential energy scans by varying appropriate dihedral angles. The obtained minimum energy conformer was further optimized at the 6-311++G (d, p) basis set by applying the most accepted B3LYP functional. A good agreement between experimental and calculated normal modes of vibration has been observed. The hydrogen-bonded interaction between two monomeric units of TICA has been investigated using NBO,QTAIM, and NCI (noncovalent interactions) analysis. Molecular docking of TICA with human placental aromatase (PDB ID: 3S79) reveals the formation of polar hydrogen bonds as well as hydrophobic interactions between the ligand and the protein, right in the binding cavity. TICA satisfies all pharmacokinetic filters (Lipinski rule of five, the Veber rule, Ghose rule, Egan rule, as well as the Muegge rule) and has a high bioavailability score of 0.85. Dynamic stability of the ligand within the binding pocket of the target protein has been confirmed by 100 ns molecular dynamics simulation results. The present study provides an excellent starting point for additional in vivo research, and TICA may eventually serve as a significant therapeutic candidate for the treatment of breast cancer.

996 EFFECT OF COVID-19 ON HIP FRACTURE CARE IN WALES - AN ANALYSIS OF HOW ORGANISATION OF SERVICES AFFECTED HOSPITAL LENGTH OF STAY

Introduction

The National Hip Fracture Database (NHFD) report that length of stay (LOS) fell (from 19.7 to 16.9 days) in the first year of the COVID-19 pandemic, as patients, families, cares, and staff in health and social care responded to this challenge. This analysis examines trends in Wales where LOS can be profiled very completely as it predominantly remains within a single health board.

Method

We used data from the NHFD www.nhfd.co.uk to define pre-pandemic LOS (in the year to 1st March 2020) and compare this with the following 18 months. We set figures for all 12 hospitals in Wales against the changes in service organisation which each reported to the NHFD's 2020 Facilities Survey, and against the local incidence of COVID-19 among their hip fracture patients.

Results

Monthly LOS fell markedly at the pandemic's onset; the national figure falling 8.3 days (from 31.2–22.9 days) between February and June 2020. Overall LOS in Wales fell by 1.6 days across the year as a whole, but this ranged from a fall of 6.3 days in one hospital to a rise of 4.5 days in another. Five hospitals reported a rise in LOS. These hospitals had either never had orthogeriatric support, or lost this to COVID-19 duties, they did not achieve the initial fall in LOS in response to the pandemic, and they reported pressures with ‘outliers’ after the first wave. Unlike other units in Wales they cited problems with workload, particularly in terms of physiotherapy.

Discussion

NHFD data provide a detailed picture of hospitals’ response to the COVID-19 pandemic, and allow us to examine service factors underpinning their resilience in the face of this challenge. More detailed work should be carried out for the 150 hospitals in England using the same sources of data.

Heterogeneity in the Epigenetic Landscape of Murine Testis-Specific Histone Variants TH2A and TH2B Sharing the Same Bi-Directional Promoter

Testis-specific histone variants are crucial to promote open chromatin structure to enable nucleosome disassembly in the final stages of spermiogenesis. However, even after histone replacement, mature sperm retain a proportion of these variants, the function of which is unknown. The present study aimed to understand the functional relevance of the retained H2B and H2A variants, TH2B and TH2A. While no literature is available on the phenotype of TH2A knockouts, TH2B/TH2A double knockout male mice are reported to be infertile. In this study, ChIP-seq analysis was done for TH2B and TH2A to understand the epigenomics of the retained TH2B and TH2A, using murine caudal sperm. Distribution across genomic partitions revealed ∼35% of the TH2B peaks within ±5 kb of TSS whereas TH2A peaks distribution was sparse at TSS. Gene Ontology revealed embryo development as the most significant term associated with TH2B. Also, based on genomic regions, TH2B was observed to be associated with spindle assembly and various meiosis-specific genes, which is an important finding as TH2A/TH2B DKO mice have been reported to have defective cohesin release. A comparison of mouse and human TH2B-linked chromatin revealed 26% overlap between murine and human TH2B-associated genes. This overlap included genes crucial for embryogenesis. Most importantly, heterogeneity in the epigenetic landscape of TH2A and TH2B was seen, which is intriguing as TH2B and TH2A are well reported to be present in the same nucleosomes to promote open chromatin. Additionally, unlike TH2B, TH2A was enriched on the mitochondrial chromosome. TH2A was found to be associated with Nuclear insertion of Mitochondrial DNA sequences (NUMTs) in sperm. A comprehensive analysis of these observations indicates novel functions for the sperm-retained TH2B and TH2A.

Structure, function and pharmacology of human itch GPCRs

The MRGPRX family of receptors (MRGPRX1-4) is a family of mas-related G-protein-coupled receptors that have evolved relatively recently1. Of these, MRGPRX2 and MRGPRX4 are key physiological and pathological mediators of itch and related mast cell-mediated hypersensitivity reactions2-5. MRGPRX2 couples to both Gi and Gq in mast cells6. Here we describe agonist-stabilized structures of MRGPRX2 coupled to Gi1 and Gq in ternary complexes with the endogenous peptide cortistatin-14 and with a synthetic agonist probe, respectively, and the development of potent antagonist probes for MRGPRX2. We also describe a specific MRGPRX4 agonist and the structure of this agonist in a complex with MRGPRX4 and Gq. Together, these findings should accelerate the structure-guided discovery of therapeutic agents for pain, itch and mast cell-mediated hypersensitivity.

Combining ALT/AST Values with Surgical APGAR Score Improves Prediction of Major Complications after Hepatectomy

Hepatectomy is a complex procedure with high morbidity and mortality. Early prediction/prevention of major complications is highly valuable for patient care. Surgical APGAR score (SAS) has been validated to predict post-surgical complications (PCs). We aimed to define a simple complications classification following hepatectomy based on a therapy-oriented severity Clavien-Dindo classification (CDC). 119 patients undergoing liver resection were included. PCs were determined at follow-up based on CDC. Clinicopathological factors were used to calculate SAS. A receiver-operator characteristic (ROC) curve analysis estimated the predictive value of SAS for PCs. Circulating markers levels of liver injury were analyzed as critical elements on PCs. SAS (P=0.008), estimated blood-loss (P=0.018) and operation time (P=0.0008) were associated with PCs. SAS was reduced in patients with (+) compared to those without (-) complications (6.64±1.84 vs 5.70±1.79, P=0.0079). The area-under-the-curve was 0.646 by ROC, indicating an acceptable discrimination with 65% possibility to distinguish (-) and (+) groups (P=0.004). Best cutoff value for SAS was ≤6/≥7, at which sensitivity and specificity were maximal. ALT/ASL levels were significantly different within the group with 9-10 SAS points (P=0.01 and 0.02). In conclusion, SAS provides accurate risk stratification for major PCs after hepatectomy, and might help improving the overall patient outcome.

Energy penalties enhance flexible receptor docking in a model cavity

Protein flexibility remains a major challenge in library docking because of difficulties in sampling conformational ensembles with accurate probabilities. Here, we use the model cavity site of T4 lysozyme L99A to test flexible receptor docking with energy penalties from molecular dynamics (MD) simulations. Crystallography with larger and smaller ligands indicates that this cavity can adopt three major conformations: open, intermediate, and closed. Since smaller ligands typically bind better to the cavity site, we anticipate an energy penalty for the cavity opening. To estimate its magnitude, we calculate conformational preferences from MD simulations. We find that including a penalty term is essential for retrospective ligand enrichment; otherwise, high-energy states dominate the docking. We then prospectively docked a library of over 900,000 compounds for new molecules binding to each conformational state. Absent a penalty term, the open conformation dominated the docking results; inclusion of this term led to a balanced sampling of ligands against each state. High ranked molecules were experimentally tested by Tm upshift and X-ray crystallography. From 33 selected molecules, we identified 18 ligands and determined 13 crystal structures. Most interesting were those bound to the open cavity, where the buried site opens to bulk solvent. Here, highly unusual ligands for this cavity had been predicted, including large ligands with polar tails; these were confirmed both by binding and by crystallography. In docking, incorporating protein flexibility with thermodynamic weightings may thus access new ligand chemotypes. The MD approach to accessing and, crucially, weighting such alternative states may find general applicability.

Retrospective Case Series Analysis of RAF Family Alterations in Pancreatic Cancer: Real-World Outcomes From Targeted and Standard Therapies

PURPOSE

In pancreatic cancer (PC), the RAF family alterations define a rare subset of patients that may predict response to inhibition of the BRAF/MEK/ERK signaling pathway. A comprehensive understanding of the molecular and clinical characteristics of RAF-mutated PC may support future development of RAF-directed strategies.

METHODS

Clinical outcomes were assessed across a multi-institutional case series of 81 patients with RAF family-mutated PC. Mutational subgroups were defined on the basis of RAF alteration hotspots and therapeutic implications.

RESULTS

The frequency of RAF alterations in PC was 2.2% (84 of 3,781) within a prevalence cohort derived from large molecular databases where BRAF V600E (Exon 15), BRAF ΔNVTAP (Exon 11), and SND1-BRAF fusions were the most common variants. In our retrospective case series, we identified 17 of 81 (21.0%) molecular profiles with a BRAF V600/Exon 15 mutation without any confounding drivers, 25 of 81 (30.9%) with BRAF or RAF1 fusions, and 18 of 81 (22.2%) with Exon 11 mutations. The remaining 21 of 81 (25.9%) profiles had atypical RAF variants and/or multiple oncogenic drivers. Clinical benefit from BRAF/MEK/ERK inhibitors was observed in 3 of 3 subjects within the V600 subgroup (two partial responses), 4 of 6 with fusions (two partial responses), 2 of 6 with Exon 11 mutations (one partial response), and 0 of 3 with confounding drivers. Outcomes analyses also suggested a trend favoring fluorouracil-based regimens over gemcitabine/nab-paclitaxel within the fusion subgroup (P = .027).

CONCLUSION

Prospective evaluation of RAF-directed therapies is warranted in RAF-mutated PC; however, differential responses to targeted agents or standard regimens for each mutational subgroup should be a consideration when designing clinical trials.

In KRAS wild-type PDAC, certain RAF alterations predict benefit from map-kinase targeted therapy

Early-Onset Pancreas Cancer: Clinical Descriptors, Genomics, and Outcomes

BACKGROUND

Recent evidence suggests a rising incidence of cancer in younger individuals. Herein, we report the epidemiologic, pathologic, and molecular characteristics of a patient cohort with early-onset pancreas cancer (EOPC).

METHODS

Institutional databases were queried for demographics, treatment history, genomic results, and outcomes. Overall survival from date of diagnosis was estimated using Kaplan-Meier method.

RESULTS

Between 2008 and 2018, 450 patients with EOPC were identified at Memorial Sloan Kettering. Median overall survival was 16.3  (95% confidence interval [CI] = 14.6 to 17.7) months in the entire cohort and 11.3  (95% CI = 10.2 to 12.2) months for patients with stage IV disease at diagnosis. Of the patients, 132 (29.3% of the cohort) underwent somatic testing; 21 of 132 (15.9%) had RAS wild-type cancers with identification of several actionable alterations, including ETV6-NTRK3, TPR-NTRK1, SCLA5-NRG1, and ATP1B1-NRG1 fusions, IDH1 R132C mutation, and mismatch repair deficiency. A total of 138 patients (30.7% of the cohort) underwent germline testing; 44 of 138 (31.9%) had a pathogenic germline variant (PGV), and 27.5% harbored alterations in cancer susceptibility genes. Of patients seen between 2015 and 2018, 30 of 193 (15.5%) had a PGV. Among 138 who underwent germline testing, those with a PGV had a reduced all-cause mortality compared with patients without a PGV controlling for stage and year of diagnosis (hazard ratio = 0.42, 95% CI = 0.26 to 0.69).

CONCLUSIONS

PGVs are present in a substantial minority of patients with EOPC. Actionable somatic alterations were identified frequently in EOPC, enriched in the RAS wild-type subgroup. These observations underpin the recent guidelines for universal germline testing and somatic profiling in pancreatic ductal adenocarcinoma.

Equal rates of drug resistance in leprosy cases with relapse and recurrent /chronic type 2 reaction; Time to revise the guidelines for drug resistance testing in leprosy

BACKGROUND

Leprosy relapse/recurrence is a serious concern especially in a leprosy endemic nation like India. It is believed that bacilli persisting even after multi-drug therapy could cause relapse; recently however drug resistance as a cause for recurrences and chronic erythema nodosum leprosum (ENL) has been speculated. Our objective was to study drug resistance patterns in cases of leprosy relapse and chronic/recurrent ENL's.

METHODOLOGY

This cross-sectional study conducted over a period of 1 year included patients diagnosed as leprosy relapse and those with chronic/recurrent (c/r) ENL. Skin biopsy specimens were subjected to conventional PCR for resistance testing for rifampicin, dapsone and ofloxacin, targeting rpoB, folP and gyrA gene of M.leprae respectively.

RESULTS

A total of 61 patients (25 smear negative) were included in the study. Of these, 37 were diagnosed as leprosy relapse and 24 had c/r ENL. Drug resistance to at least one drug was identified in 10 (16.4%) cases. Rates of drug resistance were 5.4% (2/37) for dapsone, 10.8% (4/37) for rifampicin and 2.7% (1/37) for ofloxacin amongst cases of relapse where as it was 12.5% (3/24) and 8.3% (2/24) for dapsone and rifampicin respectively amongst those with c/rENL.. Multi drug resistance was seen in 3.3% (2/61) patients.

CONCLUSION

Drug resistance rate amongst those with c/rENL was almost equaled that of relapse. Smear negative leprosy relapse cases also had resistance to bactericidal drugs. These findings call for modifications in criteria for testing under leprosy drug resistance surveillance and all cases of relapse and those with recalcitrant c/rENL should be tested.

Assessment of eco-hydrological parameters for important sympodial bamboo species in Himalayan foothills

Bamboos due to high soil water conservation potential are gaining increased attention in plantation programs across the globe. Large-scale plantation of fast-growing bamboo, however, can have important hydrological consequences. The study aims to quantify the eco-hydrological parameters, viz., throughfall (TF), stemflow (SF), and interception (I) in seven important sympodial bamboo species in north western Himalayan foothills of India. The species selected include Bambusa balcooa, Bambusa bambos, Bambusa vulgaris., Bambusa nutans, Dendrocalamus hamiltonii, Dendrocalamus stocksii, and Dendrocalamus strictus. Throughfall versus gross rainfall (GR) relationship in different species indicated high throughfall production during high rainfall events with r² > 0.90. Average throughfall was lowest (62.1%) in D. hamiltonii and highest in B. vulgaris (74.6%). SF ranged from 1.32% in B. nutans to 3.39% in D. hamiltonii. The correlation coefficient (r) between leaf area index (LAI), number of culms, and crown area with the interception were 0.746, 0.691, and 0.585, respectively. The funneling ratio (F) was highest (27.0) in D. hamiltonii and least in B. nutans. Canopy storage capacity was highest in D. strictus (3.57 mm) and least in D. hamiltonii (1.09 mm). Interception loss was highest (34.4%) in D. hamiltonii and lowest in B. vulgaris (23.5%) and D. strictus (23.6%). Higher interception in bamboos make them suitable for soil conservation, but careful selection of species is required in low rainfall areas.

Effect of prosthetic framework material, cantilever length and opposing arch on peri-implant strain in an all-on-four implant prostheses

Aim

To evaluate the effect of prosthetic framework material and cantilever length on peri-implant strain in mandibular all-on-four implant-supported prostheses with different types of arch antagonist forces.

Materials and Methods

Models simulating a completely edentulous mandibular arch fabricated in heat-cured acrylic resin were used. On the acrylic models, four implants were placed at regions 34, 32, 42, and 44 simulating all-on-four implant placements. Implant-supported screw-retained fixed prosthesis frameworks were fabricated using three different materials (cobalt-chromium, zirconia, and polyetheretherketone) and with three different cantilever lengths (zero mm, 15 mm, and 25 mm). Strain gauges were attached on the model at the buccal and lingual positions of each implant. Forces simulating opposing natural dentition, conventional complete denture, and the parafunctional habit were applied to the models. The peri-implant strain in each strain gauge was recorded.

Results

Least peri-implant strains (67 microstrains) were observed when forces simulating conventional complete dentures were applied on the models and the highest peri-implant strains (9091 microstrains) were observed when forces simulating parafunctional habit were applied. One-way ANOVA test followed by Tukey's post hoc analysis was performed to compare the mean deformation scores between different materials at 50 N load. The level of significance [P-value] was set at P < 0.05. Tests showed significant differences between zero mm and the other types in all the different materials, and also between 1.5 x AP and 2.5 x AP for Zirconia and Peek material at P = 0.02 & P = .008, respectively. The results showed that the type of framework material, cantilever length, and occlusal forces from the opposing arch influence the peri-implant strain in the bone in all-on-four implant-supported prostheses.

Conclusion

Rehabilitation of a single, completely edentulous arch with implant-supported prostheses should consider the situation of the opposing arch. The choice of framework material, as well as the cantilever length, should be altered based on the forces from the opposing arch.

An Emerging Paradigm for Germline Testing in Pancreatic Ductal Adenocarcinoma and Immediate Implications for Clinical Practice: A Review

Importance

Pancreatic ductal adenocarcinoma (PDAC) is a malignant neoplasm with a rising incidence and is a leading public health challenge. Pancreatic ductal adenocarcinoma has been well characterized genomically, with findings of therapeutic actionability that have substantive implications for clinical practice based on recent high-level evidence.

Observations

Pathogenic germline alterations (PGAs) are relatively common in individuals with PDAC, as evidenced in multiple recent data sets, with a frequency of approximately 10%. The most common PGAs are in BRCA1, BRCA2, and ATM and more rarely in PALB2, MLH1, MSH2, MSH6, PMS2, CDKN2A, and TP53, among others, with an aggregate frequency of 3.8% to 9.7%. These PGAs are of key interest owing to therapeutic actionability and the downstream identification of at-risk family members and possible hereditary cancer syndromes. Approximately 3% to 7% of individuals with PDAC harbor a BRCA1 or BRCA2 mutation, which are among the most frequently mutated genes in PDAC. Recent updates to the American Society of Clinical Oncology and the National Comprehensive Cancer Network guidelines recommend risk assessment for all individuals with PDAC irrespective of personal or family history or ethnicity. Treatment implications include the use of checkpoint inhibitor therapy for mismatch repair-deficient PDAC and the validation of poly-ADP (adenosine diphosphate)-ribose polymerase inhibitor (PARPi) therapy as a maintenance strategy in platinum-sensitive PDAC.

Conclusions and Relevance

With increasing evidence and slow improvement of outcomes, PDAC has entered the era of precision medicine. Germline mutations have been identified in key genes with an aggregate frequency of 3.8% to 9.7%, several of which are therapeutically actionable with platinum, PARPi, and checkpoint inhibitor therapy. Potential therapeutic targets need to be actively sought and identified.

Development of Novel Genomic Simple Sequence Repeat (g-SSR) Markers and Their Validation for Genetic Diversity Analyses in Kalmegh [Andrographis paniculata (Burm. F.) Nees]

Kalmegh (Andrographis paniculata (Burm. F.) Nees) is one of the most important medicinal plants and has been widely explored as traditional medicine. To exploit its natural genetic diversity and initiations of molecular breeding to develop novel cultivars or varieties, developments of genomic resources are essential. Four microsatellite-enriched genomic libraries-(CT)14, (GT)12, (AG)15 and (AAC)8-were constructed using the genomic DNA of A. paniculata. Initially, 183 recombinant colonies were screened for the presence of CT, GT, AG, and AAC microsatellite repeats, out of which 47 clones found positive for the desired simple sequence repeats (SSRs). It was found that few colonies had more than one desirable SSR. Thus, a sum of 67 SSRs were designed and synthesized for their validation among 42 A. paniculata accessions. Out of the 67 SSRs used for genotyping, only 41 were found to be polymorphic. The developed set of g-SSR markers showed substantial genetic variability among the selected A. paniculata accessions, with an average polymorphic information content (PIC) value of 0.32. Neighbor-joining tree analysis, population structure analysis, analysis of molecular variance (AMOVA), and principal coordinate analysis (PCoA) illustrated the considerable genetic diversity among them. The novel g-SSR markers developed in the present study could be important genomic resources for future applications in A. paniculata.

DFT Study on the Electronic Properties, Spectroscopic Profile, and Biological Activity of 2-Amino-5-trifluoromethyl-1,3,4-thiadiazole with Anticancer Properties

Extensive investigation on the molecular and electronic structure of 2-amino-5-trifluoromethyl-1,3,4-thiadiazole in the ground state and in the first excited state has been performed. The energy barrier corresponding to the conversion between imino and amino tautomers has been calculated, which indicates the existence of amino tautomer in solid state for the title compound. The FT-Raman and FT-IR spectra were recorded and compared with theoretical vibrational wavenumbers, and a good coherence has been observed. The MESP map, dipole moment, polarizability, and hyperpolarizability have been calculated to comprehend the properties of the title molecule. High polarizability value estimation of the title compound may enhance its bioactivity. Natural bonding orbital analysis has been done on monomer and dimer to investigate the charge delocalization and strength of hydrogen bonding, respectively. Strong hydrogen bonding interaction energies of 17.09/17.49 kcal mol^-1 have been calculated at the B3LYP/M06-2X functional. The UV-vis spectrum was recorded and related to the theoretical spectrum. The title compound was biologically examined for anticancer activity by studying the cytotoxic performance against two human cancer cell lines (A549 and HeLa) along with the molecular docking simulation. Both molecular docking and cytotoxic performance against cancer cell lines show positive outcomes, and the title compound appears to be a promising anticancer agent.

What’s in a Name? Comparative Analysis of Laboratory Test Naming Guidelines as Applied to Common Confusing Test Names

Introduction/Objective

Laboratory test names frequently do not enable easy understandability or promote correct test utilization, which leads to difficulty for providers in finding the correct test and results in unnecessary cost and medical errors. Laboratory test names are also largely unstandardized and are not named by a consistent set of conventions. To address these issues, the TRUU-Lab (Test Renaming for Understanding & Utilization) initiative aims to generate a consensus test naming guideline for better human understandability of laboratory test names. These studies address the first aim of the TRUU-Lab initiative: to identify root causes and challenges in understanding and using laboratory test names.

Methods

We conducted survey studies to capture the most problematic laboratory test names, then performed analysis of these names to identify aspects of these names that led to confusion among providers. A subset of these test names were used to evaluate five existing laboratory test naming guidelines (LOINC, ONC TigerTeam, Pan- Canadian iEHR Viewer Name, Standards for Pathology Informatics (Australia), and ARUP Laboratories internal style guides) for their ability to produce understandable test names.

Results

274 survey responses yielded ~100 unique laboratory tests cited as confusing, and highlighted substantial diversity both in the names of these tests between institutions and in respondent opinion on the best alternative names. The top 10 most commonly-cited tests yielded ≥ 3 unique names, and the top 2 tests (Vitamin D and anti- factor Xa) yielded ≥ 10 unique names. Post-survey analysis identified eight characteristics associated with poor understandability of a test name, including ambiguity, abbreviations, homophones, multiple indications for a single test, proprietary names, synonyms, truncation, and “panels” where components are obfuscated. Existing guidelines produced highly variable names given the same prompt, and varied in their ability to avoid pitfalls associated with poor understandability.

Conclusion

These studies highlight aspects of existing laboratory test names that lead to confusion among ordering providers, and identify the inability of existing laboratory test naming practices to adequately address these issues. Efforts are ongoing within TRUU-Lab to use these results to inform novel laboratory test naming guidelines to promote universal human understandability.

TRUU-Lab: Methods for Optimizing Test Names for Understanding and Utilization

Introduction/Objective

Poor understandability of laboratory test names increases the risk for inappropriate test utilization and medical errors. Yet, human understandability has not been a major consideration in existing laboratory test names or naming guidelines. TRUU-Lab (Test Renaming for Understanding and Utilization for Laboratory Test Names) is a national initiative that now has more than 45 members representing more than 20 academic and industry organizations, the CDC, and the FDA. The goals of the initiative include: 1) Identify root causes and challenges in understanding and using laboratory test names; 2) Share resources related to potential solutions; 3) Develop consensus guidelines for laboratory test naming; 4) Establish consensus names for existing laboratory tests; and 5) Promote the adoption and implementation of consensus laboratory test names.

Methods

We previously addressed the first two goals of this initiative by identifying problematic test names and features of test names that contribute to misutilization. We also identified the advantages and limitations of current test naming guidelines and previous standardization efforts. This current study addresses goals 3 and 4. We developed an iterative process of guideline development. This process includes collecting feedback on consensus names to improve guidelines, which then informs the improvement of the consensus names.

Results

By analyzing test name characteristics, we found that the requirements for understandability vary with respect to the clinical scenario and provider background. We have used these results to design a 30-min long survey to test candidate names. The survey will be distributed through the Brand Institute, which offers expertise in pharmaceutical name and brand identity development. This pilot survey will be sent to primary care providers to assesses intuitive name preferences given a short and specific prompt. The second phase will take place in a simulated electronic medical record environment to present clinical scenarios where physicians will select an appropriate test.

Conclusion

We expect that results from survey studies will directly inform the development of TRUU-Lab naming guidelines, in turn permitting development of better-optimized laboratory test names. This process represents a new strategy for the intentional design of laboratory test names that are understandable and promote correct provider utilization.

Computed tomographic analysis of the prevalence of International Frontal Sinus Anatomy Classification cells and their association with frontal sinusitis

OBJECTIVES

To determine the radiological prevalence of frontal cells according to the International Frontal Sinus Anatomy Classification in patients undergoing computed tomography of the paranasal sinuses for clinical symptoms of chronic rhinosinusitis, and to examine the association between cell classification and frontal sinusitis development.

METHODS

A total of 180 (left and right) sides of 90 patients were analysed. The prevalence of each International Frontal Sinus Anatomy Classification cell was assessed. Logistic regression analysis was used to compare the distribution of various cells in patients with and without frontal sinusitis.

RESULTS

The agger nasi cell was the most commonly occurring cell, seen in 95.5 per cent of patients. The prevalence rates for supra agger cells, supra agger frontal cells, supra bullar frontal cells, supra bullar cells, supra-orbital ethmoid cells and frontal septal cells were 33.3 per cent, 22.2 per cent, 21.1 per cent, 36.1 per cent, 39.4 per cent and 21.1 per cent, respectively. There was no significant difference in the occurrence of any of the cell types in patients with frontal sinusitis compared to those without (p > 0.05).

CONCLUSION

The presence of any of the International Frontal Sinus Anatomy Classification cells was not significantly associated with frontal sinusitis.

Comparative transcriptome analyses in contrasting onion (Allium cepa L.) genotypes for drought stress

Onion (Allium cepa L.) is an important vegetable crop widely grown for diverse culinary and nutraceutical properties. Being a shallow-rooted plant, it is prone to drought. In the present study, transcriptome sequencing of drought-tolerant (1656) and drought-sensitive (1627) onion genotypes was performed to elucidate the molecular basis of differential response to drought stress. A total of 123206 and 139252 transcripts (average transcript length: 690 bases) were generated after assembly for 1656 and 1627, respectively. Differential gene expression analyses revealed upregulation and downregulation of 1189 and 1180 genes, respectively, in 1656, whereas in 1627, upregulation and downregulation of 872 and 1292 genes, respectively, was observed. Genes encoding transcription factors, cytochrome P450, membrane transporters, and flavonoids, and those related to carbohydrate metabolism were found to exhibit a differential expression behavior in the tolerant and susceptible genotypes. The information generated can facilitate a better understanding of molecular mechanisms underlying drought response in onion.

SAT0451 COMPARISON OF PHARMACOKINETIC, PHARMACODYNAMIC AND SAFETY OF A TERIPARATIDE BIOSIMILAR AND REFERENCE TERIPARATIDE

Background:

Intas is developing a biosimilar teriparatide. This teriparatide biosimilar has shown similarity to European Union approved teriparatide (EU teriparatide) and United States approved teriparatide (US-teriparatide) in analytical (structural and functional assays) and animal studies1.

Objectives:

To primarily asses pharmacokinetic (PK) equivalence and to compare pharmacodynamic (PD) and safety profiles of teriparatide biosimilar against EU- and US-teriparatide in healthy men and postmenopausal women with potentially similar in-clinic real-life user profiles.

Methods:

In this assessor-blind, three-period study, 105 subjects were randomized (1:1:1) to receive single subcutaneous 20μg dose each of teriparatide biosimilar, EU-teriparatide, and US-teriparatide in a crossover manner on 3 consecutive days. The primary PK endpoints were area under the curve (AUC) from time zero to t (AUC0-t), AUC from time zero to infinity (AUC0-∞), and maximum concentration (Cmax). Secondary endpoints were total serum calcium level as a pharmacodynamic marker and safety.

Results:

The mean age of 48 men was 38.4 years and 57 women was 43.9 years. Mean serum teriparatide concentrations were similar for teriparatide biosimilar, EU- and US-teriparatide (Figure 1). The 90% confidence intervals (CI) of the geometric least square mean ratios (GMR) of Cmax, AUC0-tand AUC0-∞of teriparatide biosimilar relative to EU- and US-teriparatide were within the predefined acceptance range of 80.00% to 125.00% (Table 1). The baseline-adjusted and non-adjusted corrected total serum calcium levels were similar (Table 2). A total of 42 adverse events (AE) were reported by 31 (29.52%) subjects (9 subjects, teriparatide biosimilar; 14 subjects, EU-teriparatide; 13 subjects, US-teriparatide), with headache and pain in extremity being the most common AEs. No death or serious AEs were reported.

Table 1.

Summary of Statistical Analysis of Pharmacokinetic Parameters of Teriparatide

ParametersNGLSMNGLSMRatio (T/R1) %90% Confidence IntervalTeriparatide Biosimilar (T)EU-Teriparatide (R1)lnCmax(pg/mL)10499.31410499.229100.195.50 - 104.89lnAUC0-t(pg.h/mL)103130.402103129.067101.096.37 - 105.93lnAUC0-∞(pg.h/mL)103150.589103144.887103.999.19 - 108.90Teriparatide Biosimilar (T)US-Teriparatide (R2)Ratio (T/R2) %lnCmax(pg/mL)10499.25510496.397103.098.74 - 107.37lnAUC0-t(pg.h/mL)102131.212102126.837103.498.90 - 108.21lnAUC0-∞(pg.h/mL)102150.564102143.860104.799.88 - 109.67

GLSM: Geometric least squares mean; N: Number of subjects.

Table 2.

Summary of Corrected Total Serum Calcium Levels after Administration of Teriparatide

ParameterTeriparatide BiosimilarEU-TeriparatideUS-TeriparatideNMean (SD)NMean (SD)NMean (SD)Baseline-adjustedEmax(mg/dL)1010.314 (0.142)1010.333 (0.179)1020.341 (0.153)AUEC0-t(mg.h/dL)1011.764 (1.305)982.051 (1.816)1012.253 (1.732)Tmax(h)1015.457 (4.185)1015.023 (2.728)1025.252 (3.543)Baseline non-adjustedEmax(mg/dL)1049.724 (0.268)1049.719 (0.272)1049.729 (0.261)AUEC0-t(mg.h/dL)104222.215 (13.588)104223.389 (9.397)104223.972 (9.156)Tmax(h)1045.406 (4.149)1045.022 (2.691)1045.266 (3.510)Figure 1.

Mean Serum Concentration vs. Time Curve for Teriparatide

Conclusion:

This study showed PK equivalence as well as similar PD and safety profiles between teriparatide biosimilar, EU-teriparatide and US-teriparatide in healthy subjects.

References:

[1]Data on file

Disclosure of Interests:

Inderjeet Singh Employee of: Intas Pharmaceuticals Limited, Anshul Attrey Employee of: Lambda Therapeutics Research Limited, Ronak Patel Employee of: Lambda Therapeutics Research Limited, Sridevi Khambhampaty Employee of: Intas Pharmaceuticals Limited, Vinu Jose Employee of: Intas Pharmaceuticals Limited

Hormonal changes and reproductive health issues in females with tuberculosis

BACKGROUND/AIMS

The association between tuberculosis (TB) and female reproductive health issues usually remains unaddressed. TB is considered as one of the major causes of infertility in India. Because of the associated stigma, the suffering females do not discuss the problems they are facing. This may lead to disturbances in serum hormone levels also. Hence, a study was planned to find abnormalities in menstrual patterns and fertility in women in childbearing age, who were suffering from TB, and evaluate disturbances in serum hormone levels of LH, FSH, Prolactin and testosterone, if any. It also aimed to evaluate if hormone levels, or some early disturbances in menstrual cycle, can serve as a predictor for infertility in future lives.

MATERIALS AND METHODS

25 female patients each of child bearing age group from OPD/IPD: of pulmonary TB (PTB), extra pulmonary non genital TB (EPTB), extra pulmonary genital TB (GTB) and healthy controls were enrolled. Thus, a total of 75 patients with TB and 25 healthy controls were taken into the study. Patients were questioned for any abnormalities of menstrual cycle. If married, fertility status, total number of live children, abortions etc and previous history of any reproductive health issues was asked. Serum FSH, LH, Prolactin and testosterone levels on the 3rd day of the menstrual cycle were done. Data so obtained was tabulated and statistically analyzed.

RESULTS

TB patients (75/100) and healthy controls (25/100) were matched with respect to age, marital status and rural/urban background. Menstrual abnormalities, infertility and adverse events related to pregnancy were higher in patients with TB than healthy controls (p = 0.176, 0.571 and 0.005 respectively). TB patients had significantly higher levels of Testosterone and significantly lower levels of Prolactin than healthy controls (p=<0.001). Levels of FSH and LH were lower in TB patients than healthy controls (p = 0.428 and 0.274 respectively). On categorization into different types of TB, the sub-groups were matched with respect to rural/urban background. GTB was significantly higher in patients who were married (p = 0.020). Significantly higher GTB patients (10/25) reported menstrual abnormalities (p < 0.001). All the 3 infertile patients reported in the study belonged to GTB sub-group (p = 0.044). GTB had higher number of adverse events related to pregnancy followed by EPTB and PTB. Levels of FSH, LH, Testosterone and Prolactin in the three sub-groups of TB patients did not show any significant difference (p = 0.683, 0.817, 0.781, and 0.187). Since the total number of infertile patients in our study was only 3, relationship of menstrual abnormalities or serum hormone levels as a predictor of infertility could not be assessed.

CONCLUSION

Females suffering from TB experience significantly higher adverse events related to pregnancy than healthy controls. Menstrual abnormalities, infertility and adverse events related to pregnancy were more pronounced in females suffering from GTB than PTB/EPTB. Female patients suffering from any form of TB need to be comprehensively managed. Because of highly sensitive issues related to infertility and reproductive health in today's era, it is imperative that any future complications of the same are kept into consideration in female patients with TB.

72 Prevalence of Reported and Unreported Vertebral Fractures in Ctpas in Older Adults Above 75 Years

Introduction

Identifying vertebral fractures is prudent in the diagnosis of osteoporosis as they occur early in this hidden condition. Unfortunately, due to their unspecific presentation, only 25% are clinically recognised. Computerised Tomography Pulmonary Angiogram (CTPA) are frequently requested to confirm pulmonary thromboembolisms, but could also aid in detecting clinically silent vertebral fractures. Current literature suggests that less than one-third of incidental vertebral fractures are reported. The aim of this study is to measure the prevalence of vertebral fractures in CTPA and its relevance to clinical outcomes.

Methods

This is retrospective observational study based on the analysis of existing CTPA for acutely unwell patients admitted to medical assessment unit or A & E across three acute sites within Aneurin Bevan University Health board, Wales, UK between January and December 2015. All CTPA reports were reviewed for fragility factures and CTPA images were reassessed for any unreported vertebral fractures. Age and gender were recorded for all patients. Analysis was done for all patients in respect to subsequent fragility fractures and mortality. Difference of proportion test was used to compare two groups with and without vertebral fractures.

Results

179 CTPA were reviewed, 161 patients were included for further analysis. 14.3% (n=23/161) were reported to have a vertebral fracture, however only 8.7% (n=14/161) of reports used the correct terminology of ‘fracture’. On subsequent review, an additional 24.2% (n=39/161) vertebral fractures were noted. Therefore, overall prevalence of vertebral fractures was 38.5% (n=62/161). Only 9.1% (n=9/99) of patients without a vertebral fracture developed a subsequent fragility fracture. In comparison, 22.5% (n=14/62) of patients with a previous vertebral fracture sustained a new fragility fracture over next 4 years and this was significantly higher (p = 0.017). Overall mortality over 4 years follow-up was significantly higher for patients with vertebral fractures (64.5%, n=40/62) as compared to those without fractures (43.4%, n=43/99, p = 0.009). Only 48.4% (n=30/62) received osteoporosis treatment.

Conclusions

Vertebral fractures could be underreported by radiologists, likely due to human factors as they might be concentrating on the clinical scenario to exclude a pulmonary embolism. However, considering a significant higher mortality in patients with underlying vertebral fracture, it justifies that radiologists could be asked to examine sagittal view in the bone window for possible underlying vertebral fractures, to ensure osteoporosis is treated to guidance.

Young-onset pancreas cancer (PC) in patients less than or equal to 50 years old at Memorial Sloan Kettering (MSK): Descriptors, genomics, and outcomes

774

Background: For individuals ≤ 50 years old, cancer incidence is increasing, particularly gastrointestinal and obesity related cancers (Sung, Lancet Public Health 2019). Limited details are known about young onset PC. Herein, we report the epidemiologic, pathologic, and molecular characteristics of PC in patients (pts) ≤ 50 years. Methods: MSK institutional database was queried for medical and treatment history, genomics, and outcomes in pts ≤ 50 years old diagnosed with PC between January 2008 and July 2018. Neuroendocrine cancers were excluded. Overall survival (OS) from date of PC diagnosis was estimated using Kaplan-Meier methods. Results: N = 450 pts ≤ 50 years old with a diagnosis of PC were identified. Ninety-six percent had adenocarcinoma, and 4% had acinar cell carcinoma/other histologies. Table summarizes demographics. Median OS was 16 months in the entire cohort and 11.3 months in stage IV disease. For N = 236 pts diagnosed after 2014, 119 (50%) underwent successful somatic testing with at least one alteration identified, and 21/119 tumors were RAS wild-type with identification of several actionable alterations (NRG1 fusions (n=2), NTRK fusions (n=2), IDH1 R132C (n=1), and microsatellite unstable tumors (n=1) ). N = 114 pts had germline testing (routine after 2015), and 33/114 (29%) had pathologic germline alterations, including BRCA1/2 (n=18), CHEK2 (n=3), PALB2 (n=3), ATM (n=2), MLH1 (n=1), and MSH3 (n=1). Conclusions: Pathogenic germline alterations are present in a substantial percentage of pts with young onset PC, and actionable somatic alterations were seen frequently in the subgroup of young onset PC RAS-wild type tumors. These observations underpin the need for germline and somatic profiling in PC. [Table: see text]

Building better enzymes: Molecular basis of improved non-natural nucleobase incorporation by an evolved DNA polymerase

Obtaining semisynthetic microorganisms that exploit the information density of "hachimoji" DNA requires access to engineered DNA polymerases. A KlenTaq variant has been reported that incorporates the "hachimoji" P:Z nucleobase pair with a similar efficiency to that seen for Watson-Crick nucleobase incorporation by the wild type (WT) KlenTaq DNA polymerase. The variant polymerase differs from WT KlenTaq by only four amino acid substitutions, none of which are located within the active site. We now report molecular dynamics (MD) simulations on a series of binary complexes aimed at elucidating the contributions of the four amino acid substitutions to altered catalytic activity. These simulations suggest that WT KlenTaq is insufficiently flexible to be able to bind AEGIS DNA correctly, leading to the loss of key protein/DNA interactions needed to position the binary complex for efficient incorporation of the "hachimoji" Z nucleobase. In addition, we test literature hypotheses about the functional roles of each amino acid substitution and provide a molecular description of how individual residue changes contribute to the improved activity of the KlenTaq variant. We demonstrate that MD simulations have a clear role to play in systematically screening DNA polymerase variants capable of incorporating different types of nonnatural nucleobases thereby limiting the number that need to be characterized by experiment. It is now possible to build DNA molecules containing nonnatural nucleobase pairs in addition to A:T and G:C. Exploiting this development in synthetic biology requires engineered DNA polymerases that can replicate nonnatural nucleobase pairs. Computational studies on a DNA polymerase variant reveal how amino acid substitutions outside of the active site yield an enzyme that replicates nonnatural nucleobase pairs with high efficiency. This work will facilitate efforts to obtain bacteria possessing an expanded genetic alphabet.

Knowledge, attitude, and practice of general dental practitioners toward following proper standards of endodontic practice and use of latest technology in Dehradun: A cross-sectional study

Background:

Choosing latest technology for the treatment improves the chances of favorable prognosis and saves the time of the clinician; hence, the aim of the study was to explore their knowledge, attitude, and practice (KAP) toward following proper standards of endodontic practice and use of latest technology.

Materials and Methods:

The present study was a cross-sectional, descriptive questionnaire study conducted among general dental practitioners (GDPs). The survey was conducted among 156 GDPs. In the present study, a close-ended interview schedule was prepared to test the KAP of GDPs.

Results:

For diagnosis, most of the study participants (58 [37.08%]) relied on case history and radiograph. Apex locator was used by 71 (45.51%) of the study subjects. Among all the study participants, 58 (37.17%) dental practitioners used rotary nickel–titanium (NiTi) files with normal saline and preheated disinfectants for cleaning and shaping of root canal. It was observed that the knowledge of majority of the dental practitioners was fair (58 [37.17%]). However, the attitude and practice toward following proper standards of endodontic practice and use of latest technology were poor.

Conclusion:

It was concluded that very few general practitioners used the latest technology in endodontics. Knowledge was fair while attitude and practice regarding following proper standards of endodontic practice and use of latest technology were poor among study participants.