Antibody targeting of conserved sites of vulnerability on the SARS-CoV-2 spike receptor-binding domain

Given the continuous emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VoCs), immunotherapeutics that target conserved epitopes on the spike (S) glycoprotein have therapeutic advantages. Here, we report the crystal structure of the SARS-CoV-2 S receptor-binding domain (RBD) at 1.95 Å and describe flexibility and distinct conformations of the angiotensin-converting enzyme 2 (ACE2)-binding site. We identify a set of SARS-CoV-2-reactive monoclonal antibodies (mAbs) with broad RBD cross-reactivity including SARS-CoV-2 Omicron subvariants, SARS-CoV-1, and other sarbecoviruses and determine the crystal structures of mAb-RBD complexes with Ab246 and CR3022 mAbs targeting the class IV site, WRAIR-2134, which binds the recently designated class V epitope, and WRAIR-2123, the class I ACE2-binding site. The broad reactivity of class IV and V mAbs to conserved regions of SARS-CoV-2 VoCs and other sarbecovirus provides a framework for long-term immunotherapeutic development strategies.

The effect of ziltivekimab on the neutrophil-lymphocyte ratio: analysis from RESCUE

Background

The neutrophil-lymphocyte ratio (NLR), derived from the complete blood count, independently predicts atherosclerotic events and is a potential biomarker for residual inflammatory risk. A previous study showed that interleukin (IL)-1β inhibition reduces the NLR, but whether inhibition with IL-6, a cytokine downstream of IL-1, also lowers the NLR is unknown.

Purpose

To evaluate whether ziltivekimab, a monoclonal antibody targeting the IL-6 ligand, dose-dependently lowers the NLR compared to placebo.

Methods

The phase II RESCUE trial randomized 264 patients with moderate to severe chronic kidney disease (CKD) and high-sensitivity CRP (hsCRP) >2mg/L in a 1:1:1:1 ratio to placebo or ziltivekimab 7.5 mg, 15 mg, and 30 mg subcutaneously once every four weeks. As previously reported, the trial met its primary endpoint as demonstrated by hsCRP reductions of 4% in the placebo group as compared to 77%, 88%, and 92% at 12 weeks in the ziltivekimab 7.5, 15, and 30 mg groups, respectively. Using RESCUE trial data, we further evaluated the percent change from baseline in the NLR at 12 weeks and sought evidence of correlation between any observed changes in the NLR with changes in other measured biomarkers.

Results

Ziltivekimab dose-dependently reduced the NLR starting at week one and sustained through week 12 (Table). The median change in the NLR at 12 weeks, the primary pre-specified endpoint, was −13.5% in the 7.5 mg group, −14.3% in the 15 mg group, and −22.4% in the 30 mg group compared to 1.56% in the placebo group. The estimated treatment difference was −14.6% (p=0.004), −15.3% (p=0.004), and −23.6% (p<0.0001) in the ziltivekimab 7.5, 15, and 30 mg groups respectively. These changes were driven largely by reductions in the absolute neutrophil count with minimal change in lymphocyte count. The change in NLR with ziltivekimab correlated modestly with the changes in hsCRP (R=0.26, p=0.0006), fibrinogen (R=0.18, p=0.02), and haptoglobin (R=0.17, p=0.03), but not serum amyloid A, ApoA1, ApoB, ApoB/ApoA ratio, or traditional risk markers.

Conclusions

IL-6 inhibition with ziltivekimab lowers the NLR. The ongoing ZEUS cardiovascular (CV) outcomes trial will assess whether ziltivekimab can reduce CV event rates among individuals with stage 3 to 4 CKD, known atherosclerotic disease, and elevated hsCRP. If ziltivekimab reduces CV risk, it would provide further evidence for critical inter-relationships between bone marrow function and atherothrombosis.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Novo Nordisk

Correlation of arterial PaCO2 to end tidal CO2 in children undergoing laparoscopic abdominal surgery: An observational study

Background and Aims

The reliability of end tidal carbon dioxide (ETCO2) as a measure of arterial carbon dioxide (PaCO2) in pediatric laparoscopy is unclear. We evaluated the correlation of arterial to end tidal P(a-ET) CO2 during pediatric laparoscopy at two hours of pneumoperitoneum as the primary objective. We also compared P(a-ET) CO2 and alveolar to arterial oxygen gradient P(A-a) O2 and haemodynamics at fixed time points during surgery.

Material and Methods

A cross-sectional study was conducted in 25 children undergoing laparoscopic abdominal surgery. Arterial blood gases were drawn at T0, baseline, T10: ten minutes, T1h: 1 hour, T2h: 2 hours of pnuemoperitoneum and T 10d: 10 mins after deflation. The P(a-ET) CO2, P(A-a) O2, were measured from the blood gas and ETCO2 and FiO2 values on the monitor. The Pearson's correlation coefficient, the Wilcoxon rank test and Chi square test were used for statistical analysis.

Results

At T2h moderate correlation of P(a-ET) CO2 (r = 0.605, P = 0.001) with 40% children documenting accurate P(a-ET) CO2, -1 to +1 mm Hg was seen. Moderate correlation was also seen at T0, T10, T 10d but poor correlation at T 1h. The P(A-a) O2 increased progressively with surgery and did not correlate with P(a-ET) CO2. Heart rate was stable, but systolic blood pressures at T 10 and diastolic at T10, T 1h, T 2h were higher than baseline.

Conclusion

Moderate correlation was seen between PaCO2 and ETCO2 at 2 h of pnuemoperitoneum and at T0, T 10, and T 10d. P(A-a) O2 increased with surgery but did not correlate with P(a-ET) CO2.

SARS-CoV-2 ferritin nanoparticle vaccines elicit broad SARS coronavirus immunogenicity

The need for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) next-generation vaccines has been highlighted by the rise of variants of concern (VoCs) and the long-term threat of emerging coronaviruses. Here, we design and characterize four categories of engineered nanoparticle immunogens that recapitulate the structural and antigenic properties of the prefusion SARS-CoV-2 spike (S), S1, and receptor-binding domain (RBD). These immunogens induce robust S binding, ACE2 inhibition, and authentic and pseudovirus neutralizing antibodies against SARS-CoV-2. A spike-ferritin nanoparticle (SpFN) vaccine elicits neutralizing titers (ID50 > 10,000) following a single immunization, whereas RBD-ferritin nanoparticle (RFN) immunogens elicit similar responses after two immunizations and also show durable and potent neutralization against circulating VoCs. Passive transfer of immunoglobulin G (IgG) purified from SpFN- or RFN-immunized mice protects K18-hACE2 transgenic mice from a lethal SARS-CoV-2 challenge. Furthermore, S-domain nanoparticle immunization elicits ACE2-blocking activity and ID50 neutralizing antibody titers >2,000 against SARS-CoV-1, highlighting the broad response elicited by these immunogens.

Neutrophil-to-lymphocyte ratio predicts cardiovascular events in patients with type 2 diabetes: post hoc analysis of SUSTAIN 6 and PIONEER 6

Background

Inflammation plays an important role in atherosclerosis. The neutrophil-to-lymphocyte ratio (NLR) may serve as a clinically useful biomarker of inflammation and cardiovascular (CV) disease, although this relationship has not been studied in people with type 2 diabetes (T2D).

Purpose

This post hoc analysis investigated the relationship between NLRs and CV outcomes in T2D CV outcomes trials for two formulations of semaglutide, a glucagon-like peptide-1 receptor agonist.

Methods

In pooled analyses of the SUSTAIN 6 and PIONEER 6 trials, 6,480 patients with T2D at high CV risk received placebo or semaglutide (once-weekly subcutaneously up to 1.0 mg, or once-daily orally up to 14 mg). NLRs were calculated from complete blood counts at randomisation. Adjudicated outcomes included 3-point major adverse CV events (MACE: composite of CV death, non-fatal myocardial infarction [MI] or non-fatal stroke; primary outcome), expanded MACE, CV death and all-cause death (secondary outcomes). Patient characteristics and CV outcomes were analysed according to baseline NLR tertiles using pooled trial data. Estimation of hazard ratios (HRs) for all outcomes across NLR tertiles used a Cox proportional hazards model. A Cox spline regression with continuous NLR as covariate adjusted for treatment was used to predict the event rate of first MACE at 2 years.

Results

Overall, baseline NLR was recorded in 6,364 patients. Mean baseline NLRs were 1.5, 2.2 and 3.6 in the low, middle and high tertiles, respectively. Patients in the high NLR tertile were older (66.6 years), more likely to be male (70.0%), had longer duration of diabetes (15.3 years), higher body weight (93.3 kg), lower diastolic blood pressure (75.5 mmHg) and estimated glomerular filtration rate (70.4 mL/min/1.73m2) vs those in the lower NLR tertiles (all p<0.0001). Higher NLR was associated with an increased risk of MACE (HR [95% confidence interval (CI)]: 1.37 [1.05; 1.80; p=0.02] and 1.86 [1.45; 2.41; p<0.0001] for the middle and high tertiles, respectively, vs the low tertile). The high NLR tertile was also associated with a 74% increased risk of expanded MACE and twofold risk for CV death and all-cause death vs the low NLR tertile (Figure 1). Spline regression indicated that NLR values >5 increased the risk of first MACE substantially (Figure 2). Further analysis of NLR and MACE by tertiles showed a more pronounced association in patients without prior MI and/or stroke (HR [95% CI]: 1.64 [1.07; 2.56]; p=0.03 and 2.09 [1.38; 3.21]; p=0.0006 in the middle and high tertiles, respectively, vs the low tertile).

Conclusion

Baseline NLR predicts MACE, CV death and all-cause death in patients with T2D and high CV risk. NLR is readily accessible from routinely obtained and inexpensive blood counts; it could offer a convenient, clinically useful inflammatory biomarker for CV risk prediction in this population.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Novo Nordisk A/S Figure 1Figure 2

SARS-CoV-2 ferritin nanoparticle vaccines elicit broad SARS coronavirus immunogenicity

The need for SARS-CoV-2 next-generation vaccines has been highlighted by the rise of variants of concern (VoC) and the long-term threat of other coronaviruses. Here, we designed and characterized four categories of engineered nanoparticle immunogens that recapitulate the structural and antigenic properties of prefusion Spike (S), S1 and RBD. These immunogens induced robust S-binding, ACE2-inhibition, and authentic and pseudovirus neutralizing antibodies against SARS-CoV-2 in mice. A Spike-ferritin nanoparticle (SpFN) vaccine elicited neutralizing titers more than 20-fold higher than convalescent donor serum, following a single immunization, while RBD-Ferritin nanoparticle (RFN) immunogens elicited similar responses after two immunizations. Passive transfer of IgG purified from SpFN- or RFN-immunized mice protected K18-hACE2 transgenic mice from a lethal SARS-CoV-2 virus challenge. Furthermore, SpFN- and RFN-immunization elicited ACE2 blocking activity and neutralizing ID50 antibody titers >2,000 against SARS-CoV-1, along with high magnitude neutralizing titers against major VoC. These results provide design strategies for pan-coronavirus vaccine development.

HIGHLIGHTS

Iterative structure-based design of four Spike-domain Ferritin nanoparticle classes of immunogensSpFN-ALFQ and RFN-ALFQ immunization elicits potent neutralizing activity against SARS-CoV-2, variants of concern, and SARS-CoV-1Passively transferred IgG from immunized C57BL/6 mice protects K18-hACE2 mice from lethal SARS-CoV-2 challenge.

P33: PROPOSAL OF A NEW SCORING TOOL FOR PREDICTION OF HYPOCALCEMIA IN PATIENTS UNDERGOING SURGERY FOR PAPILLARY THYROID CANCER

Introduction

Post-operative hypocalcemia occurs more frequently in certain high-risk patients. The aim of our study is to propose a preliminary scoring system to identify patients who are more likely to develop hypocalcemia following surgery for papillary thyroid cancer.

Method

The study was performed with a retrospective developmental cohort(n=131) and a prospective validation cohort(n=71). Patients underwent either Total Thyroidectomy(TT), TT+Central Neck Dissection(CND) or TT+CND+Modified Radical Neck Dissection(MRND). Significant pre-operative variables and operative findings were converted into categorical variables for analysis. Univariate, multivariate analysis and a logistic regression were used to select significant predictors. The score was constructed by converting into integer, the regression coefficients of independently predictive factors in the logistic regression model. This score was validated prospectively in the validation cohort.

Result

24(18%) out of 131 patients in the developmental cohort and 16(22.5%) out of 71 patients in the validation cohort had symptomatic hypocalcemia. Thyroiditis, positive lymph node metastasis, central and lateral compartment dissection, Neutrophil-to-lymphocyte ratio(NLR)>3.35 and platelet-to-lymphocyte ratio(PLR)>135 were selected as significant predictors. A score with a range of 0-11 was created. The cut-off value for the score was 6 points(sensitivity of 92.0% and specificity of 89.0%). Areas under the ROC curve for the scores were 0.926 and 0.901 in the developmental and validation cohorts, respectively.

Conclusion

This score could be a tool in the prediction of hypocalcemia and could help in identifying patients at a higher risk of post-operative hypocalcemia and guide calcium/Vitamin D treatment, as well as facilitate a safe earlier hospital discharge for low risk patients.

Take-home message

The proposed scoring system could help in identification of patients at a higher risk of post-operative hypocalcemia.

P32: POST-OPERATIVE RELATIVE PARATHORMONE DECLINE (ΔPTH%) AND ABSOLUTE PARATHORMONE DECLINE (ΔPTH) LEVELS ARE BETTER MARKERS OF SYMPTOMATIC HYPOCALCEMIA FOLLOWING TOTAL THYROIDECTOMY THAN POST-OPERATIVE PTH ALONE

Introduction

Hypocalcemia is a frequent complication following thyroidectomy which can delay discharge and increase overall treatment expenditure. We aimed to assess the predictive value of absolute and relative intact Parathormone(iPTH) decline levels as reliable markers of post-operative hypocalcemia.

Method

This prospective study included 95 consecutive patients at our tertiary care centre. Patients underwent either Total Thyroidectomy(TT), TT+Central Neck Dissection(CND) or TT+CND+Modified Radical Neck Dissection(MRND). iPTH levels were measured four hours after surgery and the following morning after surgery(POD 1). iPTH, absolute iPTH decline(ΔPTH) and relative iPTH decline(ΔPTH%) were calculated and correlated with hypocalcemia. Comparisons between groups were measured by chi-square test, Fischer's exact test and Mann-Whitney U test.

Result

Of the 95 patients, 59 had malignant disease, while 36 patients had benign histopathology. TT was performed in 69 patients, TT+CCLND in 7, and TT+CCLND+MRND in 19. 32.6% of patients(n=31) had biochemical hypocalcemia and 20%(n=19) had symptomatic hypocalcemia. The mean calcium of the cohort on Post-operative day(POD)-1 was 8.3±0.66(range=6.5-9.9) and POD-3 was 8.4±0.69(range=6.3–10.7). Median PTH, measured 4 hours after surgery was 24pg/ml(IQR–23.4;range 2.5–85.5), and measured on POD-1 was 28pg/ml(IQR–27.6;range=2-79). The ΔPTH(U=206;p<0.001) & ΔPTH% (U=127;p<0.001) were significantly higher in patients with symptomatic hypocalcemia. A ΔPTH% of 20%(sensitivity=84%;specificity=91%) and ΔPTH of 3.75 pg/ml(sensitivity = 74%; specificity=87%) were good predictors of symptomatic hypocalcemia.

Conclusion

Post-operative ΔPTH and ΔPTH% are reliable predictors of hypocalcemia following thyroid surgery and have the potential to facilitate a safe early discharge for patients undergoing TT. 20% fall in the PTH level(ΔPTH%) can be useful as a marker of hypocalcemia.

Take-home message

Post-operative ΔPTH and ΔPTH% are better predictors of hypocalcemia following thyroid surgery than a single value of post-operative PTH alone.

Short-course radiotherapy with consolidation chemotherapy versus conventionally fractionated long-course chemoradiotherapy for locally advanced rectal cancer: randomized clinical trial

BACKGROUND

The trial hypothesis was that, in a resource-constrained situation, short-course radiotherapy would improve treatment compliance compared with conventional chemoradiotherapy for locally advanced rectal cancer, without compromising oncological outcomes.

METHODS

In this open-label RCT, patients with cT3, cT4 or node-positive non-metastatic rectal cancer were allocated randomly to 5 × 5 Gy radiotherapy and two cycles of XELOX (arm A) or chemoradiotherapy with concurrent capecitabine (arm B), followed by total mesorectal excision in both arms. All patients received a further six cycles of adjuvant chemotherapy with the XELOX regimen. The primary endpoint was treatment compliance, defined as the ability to complete planned treatment, including neoadjuvant radiochemotherapy, surgery, and adjuvant chemotherapy to a dose of six cycles.

RESULTS

Of 162 allocated patients, 140 were eligible for analysis: 69 in arm A and 71 in arm B. Compliance with planned treatment (primary endpoint) was greater in arm A (63 versus 41 per cent; P = 0.005). The incidence of acute toxicities of neoadjuvant therapy was similar (haematological: 28 versus 32 per cent, P = 0.533; gastrointestinal: 14 versus 21 per cent, P = 0.305; grade III-IV: 2 versus 4 per cent, P = 1.000). Delays in radiotherapy were less common in arm A (9 versus 45 per cent; P < 0.001), and overall times for completion of neoadjuvant treatment were shorter (P < 0.001). The rates of R0 resection (87 versus 90 per cent; P = 0.554), sphincter preservation (32 versus 35 per cent; P = 0.708), pathological complete response (12 versus 10 per cent; P = 0.740), and overall tumour downstaging (75 versus 75 per cent; P = 0.920) were similar. Downstaging of the primary tumour (ypT) was more common in arm A (P = 0.044). There was no difference in postoperative complications between trial arms (P = 0.838).

CONCLUSION

Reduced treatment delays and a higher rate of compliance were observed with treatment for short-course radiotherapy with consolidation chemotherapy, with no difference in early oncological surgical outcomes. In time- and resource-constrained rectal cancer units in developing countries, short-course radiotherapy should be the standard of care.

No change in life expectancy: the devil is in the detail

Background

The rate of improvement in life expectancy in high income countries has slowed down over the past few years, and instances where life expectancy is lower than a year before are increasingly common. This paper aims to analyse changes in life expectancy over the last decade to better understand what causes and age groups contribute to the slowdown.

Methods

We use WHO mortality data by age and cause to construct life tables, and we use Arriaga decomposition method to analyse the contribution of specific causes and age groups to changes in life expectancy in Australia, Canada, France, Germany, Netherlands, United Kingdom and the United States of America. We look at the change between 2007-2012 and 2012-2017 (or latest available).

Results

All countries experienced a slowdown in life expectancy in the past 5 years (2012-2017), in comparison to the preceding period. Slowdown in under 65s was particularly pronounced, with younger age groups only contributing minimally (between 0.4 years for males in Germany and -0.4 years for males in the United States) to changes in life expectancy. Among people aged 65 and over, gains ranged between 0.05 years for females in France and 0.6 years for males in the Netherlands. Certain causes of death contributed negatively to change in life expectancy between 2012 and 2017, with notable increases in deaths from accidental poisonings in males (up to -0.09 year in the UK and Canada, and -0.34 in the US) and suicides (up to -0.08 year in Australia and -0.07 in the US).

Conclusions

While recent slowdown in life expectancy gains in high income countries is often attributed to lack of improvement in people of older ages, we show that, beyond this, there are increases in mortality in younger age groups from external causes, that contribute negatively to change in life expectancy in some countries. This pattern is of a particular concern, as deterioration in preventable mortality points to broader worsening of socio-economic climate.

Key messages

Improvements in life expectancy in high income countries slowed down markedly over the past few years, but contributing mortality patterns differ for age groups and causes of death across countries. Persistent increases in preventable mortality from certain external causes in younger age groups in Australia, Canada, US and UK point to broader deterioration of socio-economic climate.

Machine Learning-Based Segmentation of Left Ventricular Myocardial Fibrosis from Magnetic Resonance Imaging

PURPOSE OF REVIEW

Myocardial fibrosis (MF) arises due to myocardial infarction and numerous cardiac diseases. MF may lead to several heart disorders, such as heart failure, arrhythmias, and ischemia. Cardiac magnetic resonance (CMR) imaging techniques, such as late gadolinium enhancement (LGE) CMR, enable non-invasive assessment of MF in the left ventricle (LV). Manual assessment of MF on CMR is a tedious and time-consuming task that is subject to high observer variability. Automated segmentation and quantification of MF is important for risk stratification and treatment planning in patients with heart disorders. This article aims to review the machine learning (ML)-based methodologies developed for MF quantification in the LV using CMR images.

RECENT FINDINGS

With the availability of relatively large labeled datasets supervised learning methods based on both conventional ML and state-of-the-art deep learning (DL) methods have been successfully applied for automated segmentation of MF. The incorporation of ML algorithms into imaging techniques such as 3D LGE CMR permits fast characterization of MF on CMR imaging and may enhance the diagnosis and prognosis of patients with heart disorders. Concurrently, the studies using cine CMR images have revealed that accurate segmentation of MF on non-contrast CMR imaging might be possible. The application of ML/DL tools in CMR image interpretation is likely to result in accurate and efficient quantification of MF.

Preclinical Characterization of an Antibody-Drug Conjugate Targeting CS-1 and the Identification of Uncharacterized Populations of CS-1-Positive Cells

Multiple myeloma is a hematologic cancer that disrupts normal bone marrow function and has multiple lines of therapeutic options, but is incurable as patients ultimately relapse. We developed a novel antibody-drug conjugate (ADC) targeting CS-1, a protein that is highly expressed on multiple myeloma tumor cells. The anti-CS-1 mAb specifically bound to cells expressing CS-1 and, when conjugated to a cytotoxic pyrrolobenzodiazepine payload, reduced the viability of multiple myeloma cell lines in vitro In mouse models of multiple myeloma, a single administration of the CS-1 ADC caused durable regressions in disseminated models and complete regression in a subcutaneous model. In an exploratory study in cynomolgus monkeys, the CS-1 ADC demonstrated a half-life of 3 to 6 days; however, no highest nonseverely toxic dose was achieved, as bone marrow toxicity was dose limiting. Bone marrow from dosed monkeys showed reductions in progenitor cells as compared with normal marrow. In vitro cell killing assays demonstrated that the CS-1 ADC substantially reduced the number of progenitor cells in healthy bone marrow, leading us to identify previously unreported CS-1 expression on a small population of progenitor cells in the myeloid-erythroid lineage. This finding suggests that bone marrow toxicity is the result of both on-target and off-target killing by the ADC.

Screening of Weight-Loss Herbal Products for Synthetic Anti-Obesity Adulterants: A Target-Oriented Analysis by Liquid Chromatography-Tandem Mass Spectrometry

BACKGROUND

The medical and social impact of being overweight, as well as the difficulty in making long-term changes in diet, physical activity, and pitfalls associated with allopathic management, lure obese individuals to over-the-counter weight-loss herbal products (WHPs). However, the safety of herbals is questionable, as reports from all over the world suggest adulteration with synthetic weight loss agents. Objective: The present study was carried out to develop a rapid and sensitive method to screen potential weight loss adulterants in WHPs. Methodology: We procured 33 licensed brands of WHPs that are available in Puducherry (India) and through web stores. Drug-free spiked herbal matrices were used for internal proficiency testing. Spiked herbal matrices and samples were extracted and centrifuged. The supernatant was collected and subjected to liquid chromatography-tandem mass spectrometry analyses. Isocratic elution was carried out by the mobile phase of methanol: 0.1% v/v formic acid (70%:30% v/v) through a C₁₈ column. Analytes were monitored in electrospray ionization positive and negative modes, and an multiple reaction monitoring (MRM) scan was used. Results: Run time was 12 min. Intra- and inter-day precision was < 15% and recoveries were in the range of 99% to 115%. Limit of quantification (LOQ) of the analytes were in the range of 0.1 to 0.3 ng/ml. Conclusion: We developed a sensitive and rapid validated method for the detection of potential adulterants in WHPs. None of the WHPs analyzed were found to contain adulterants. The proposed method will be useful for routine monitoring. WHPs analyzed in this study were not adulterated indicating that WHPs from licensed sources are reliable.

Computer-Based Substance Use Reporting and Acceptance of HIV Testing Among Emergency Department Patients

More than 10 years after the Centers for Disease Control and Prevention recommended routine HIV testing for patients in emergency departments (ED) and other clinical settings, as many as three out of four patients may not be offered testing, and those who are offered testing frequently decline. The current study examines how participant characteristics, including demographics and reported substance use, influence the efficacy of a video-based intervention designed to increase HIV testing among ED patients who initially declined tests offered by hospital staff. Data from three separate trials in a high volume New York City ED were merged to determine whether patients (N = 560) were more likely to test post-intervention if: (1) they resembled people who appeared onscreen in terms of gender or race; or (2) they reported problem substance use. Chi Square and logistic regression analyses indicated demographic concordance did not significantly increase likelihood of accepting an HIV test. However, participants who reported problem substance use (n = 231) were significantly more likely to test for HIV in comparison to participants who reported either no problem substance use (n = 190) or no substance use at all (n = 125) (x² = 6.830, p < 0.05). Specifically, 36.4% of patients who reported problem substance use tested for HIV post-intervention compared to 30.5% of patients who did not report problem substance use and 28.8% of participants who did not report substance use at all. This may be an important finding because substance use, including heavy alcohol or cannabis use, can lead to behaviors that increase HIV risk, such as sex with multiple partners or decreased condom use.

Post-mitotic odontoblasts in health, disease, and regeneration

OBJECTIVE

Description of the odontoblast lifecycle, an overview of the known complex molecular interactions that occur when the health of the dental pulp is challenged and the current and future management strategies on vital and non-vital teeth.

METHODS

A literature search of the electronic databases included MEDLINE (1966-April 2019), CINAHL (1982-April 2019), EMBASE and EMBASE Classic (1947-April 2019), and hand searches of references retrieved were undertaken using the following MESH terms 'odontoblast*', 'inflammation', 'dental pulp*', 'wound healing' and 'regenerative medicine'.

RESULTS

Odontoblasts have a sensory and mechano-transduction role so as to detect external stimuli that challenge the dental pulp. On detection, odontoblasts stimulate the innate immunity by activating defence mechanisms key in the healing and repair mechanisms of the tooth. A better understanding of the role of odontoblasts within the dental pulp complex will allow an opportunity for biological management to remove the cause of the insult to the dental pulp, modulate the inflammatory process, and promote the healing and repair capabilities of the tooth. Current strategies include use of conventional dental pulp medicaments while newer methods include bioactive molecules, epigenetic modifications and tissue engineering.

CONCLUSION

Regenerative medicine methods are in their infancy and experimental stages at best. This review highlights the future direction of dental caries management and consequently research.

P4439Increased risk of out-of-hospital cardiac arrest in patients with psoriasis - a nationwide case-control study

Background

Chronic inflammatory disorders such as psoriasis have been associated with cardiovascular diseases and linked to proarrhythmogenic electrocardiographic changes, including QT-prolongation. However, evidence regarding the risk of out-of-hospital cardiac arrest with a history of psoriasis is lacking.

Purpose

To investigate the association between psoriasis and out-of-hospital cardiac arrest.

Methods

Through the nationwide Danish Cardiac Arrest Registry, we identified adult out-of-hospital cardiac arrest patients of presumed cardiac cause with and without psoriasis between June 2001 and December 2014. The odds of cardiac arrest were estimated using conditional logistic regression in a case-control design where we matched up to nine controls per case on age, sex and ischemic heart disease. The models were adjusted for comorbidities, concomitant pharmacotherapy and socioeconomic position.

Results

A total of 32,447 out-of-hospital cardiac arrest cases were included and matched with 291,999 controls from the general population. The median age was 72 years, 67% were male and 29% had ischemic heart disease. A total of 607 (1.9%) cases and 4662 (1.6%) controls had psoriasis. Compared with cardiac arrest cases without psoriasis, cases with psoriasis had same age (p=0.718) and gender distribution (p=0.794), higher prevalence of comorbidities such as congestive heart failure (25.7% vs 20.2%, p=0.001), chronic kidney disease (8.9% vs 6.2%, p=0.008) and chronic obstructive pulmonary disease (19.0% vs 14.7%, p=0.005) but had same prevalence of cerebral vascular disease (15.8% vs 14.5%, p=0.351) and peripheral vascular disease (13.3% vs 11.1%, p=0.078). In unadjusted and adjusted analyses, psoriasis was significantly associated with increased odds of cardiac arrest (odds ratio (OR) 1.18 [95% confidence interval (CI) 1.08–1.28] and OR 1.13 [95% CI 1.04–1.23], respectively) (Figure 1).

Conclusion

In this nationwide case-control study, psoriasis was significantly associated with increased odds of out-of-hospital cardiac arrest. Focus on risk factors and prevention of cardiovascular disease in patients with psoriasis is warranted.

Acknowledgement/Funding

None

5225Bystander cardiopulmonary resuscitation and survival in out-of-hospital cardiac arrest of non-cardiac origin

Background

Knowledge about the effect of bystander cardiopulmonary resuscitation (CPR) in out-of-hospital cardiac arrest (OHCA) of non-cardiac origin is lacking. We aimed to investigate the association between bystander CPR and survival in OHCA of presumed non-cardiac origin.

Methods

From the Danish Cardiac Arrest Registry and through linkage with national Danish healthcare registries we identified all adult patients with OHCA of presumed non-cardiac origin in Denmark (2001–2014). These were categorized further into OHCA of medical and non-medical cause. We analyzed temporal trends in bystander CPR and 30-day survival during the study period. Multiple logistic regression was used to examine the association between bystander CPR and 30-day survival and reported as standardized 30-day survival chances with versus without bystander CPR standardized to the prehospital OHCA-factors and patient characteristics of all patients in the study population.

Results

We identified 10,761 OHCAs of presumed non-cardiac origin. Bystander CPR was associated with an increased 30-day survival chance of 3.4% (95% confidence interval [CI]: 2.9–3.9) versus 1.8% (95% CI: 1.4–2.2) with no bystander CPR, corresponding to a significant difference of 1.6% (95% CI: 0.9–2.3). During the study period, the overall bystander CPR rates increased from 13.6% (95% CI: 11.2–16.5) to 62.7% (95% CI: 60.2–65.2). 30-day survival increased overall from 1.3% (95% CI: 0.7–2.6) to 4.0% (95% CI: 3.1–5.2). Similar findings were observed in subgroups of medical and non-medical OHCA.

Table 1. Patient and arrest characteristics according to cause of out-of-hospital cardiac arrest Overall Medical OHCA Non-medical OHCA Patient characteristics   Total patients 10761 7625 3136   Median age,y 67 70 50   Male, n (%) 6357 (59.1) 4154 (54.5) 2204 (70.4) OHCA factors   Witnessed arrest, n (%) 4306 (40.0) 3574 (46.9) 732 (23.3)   Public location, n (%) 6979 (64.9) 5494 (72.1) 1485 (47.4) OHCA, out-of-hospital cardiac arrest; CPR, cardiopulmonary resuscitation.

Figure 1. Temporal trends

Conclusion

Bystander CPR was associated with a higher chance of 30-day survival among OHCA of presumed non-cardiac origin regardless of the underlying cause (medical/non-medical). Rates of bystander CPR and 30-day survival improved during the study period.

Screening of herbal medicines for potential allopathic antidiabetic adulterants: An analytical study

Background:

There are several reports worldwide on adulteration of herbal medicines (HMs) with allopathic drugs. In India, only a few studies have reported adulteration of HMs with antidiabetics and there are no systematic studies.

Aims:

To develop a rapid and validated method for detection of allopathic antidiabetic adulterants and to explore the extent of adulteration in HMs sold in South India.

Materials and Methods:

Standards and solvents were purchased from Sigma-Aldrich. Different brands of antidiabetic HM samples with manufacturing licenses were procured from dispensaries. Spiked drug free psyllium husk as solid and flask seed oil as liquid herbal matrices were used for method development. The spiked matrices with different concentrations were extracted with methanol and subjected to centrifugation. The supernatant was collected and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Isocratic elution was carried on a C18 column with 0.1% (v/v) formic acid:methanol (3:7, v/v) as a mobile phase. All drugs were monitored for two ion products in positive electrospray ionization mode using multiple reaction monitoring scans.

Results:

The retention time was 9 min. Limit of detection is 10 Pictograms (pg) for all analytes except for metformin, which was 370 pg. Recoveries of analytes range from 96% to 117%. Forty different brands of antidiabetic HMs were analyzed. Adulterant peaks were not observed in the mass chromatograms of HMs.

Conclusions:

A single-run method was developed by LC-MS/MS for the detection of proposed antidiabetics in HMs from licensed manufacturing units and online sold HMs across herbal dispensaries in Puducherry union territory, India. None of the HMs was found to be adulterated with proposed allopathic antidiabetic adulterants.

Bystander cardiopulmonary resuscitation and survival in patients with out-of-hospital cardiac arrest of non-cardiac origin

BACKGROUND

Knowledge about the effect of bystander cardiopulmonary resuscitation (CPR) in out-of-hospital cardiac arrest (OHCA) of non-cardiac origin is lacking. We aimed to investigate the association between bystander CPR and survival in OHCA of presumed non-cardiac origin.

METHODS

From the Danish Cardiac Arrest Registry and through linkage with national Danish healthcare registries we identified all patients with OHCA of presumed non-cardiac origin in Denmark (2001-2014). These were categorized further into OHCA of medical and non-medical cause. We analyzed temporal trends in bystander CPR and 30-day survival during the study period. Multiple logistic regression was used to examine the association between bystander CPR and 30-day survival and reported as standardized 30-day survival chances with versus without bystander CPR standardized to the prehospital OHCA-factors and patient characteristics of all patients in the study population.

RESULTS

We identified 10,761 OHCAs of presumed non-cardiac origin. Bystander CPR was associated with a significantly higher 30-day survival chance of 3.4% (95% confidence interval [CI]: 2.9-3.9) versus 1.8% (95% CI: 1.4-2.2) without bystander CPR. A similar association was found in subgroups of both medical and non-medical OHCA. During the study period, the overall bystander CPR rates increased from 13.6% (95% CI: 11.2-16.5) to 62.7% (95% CI: 60.2-65.2). 30-day survival increased overall from 1.3% (95% CI: 0.7-2.6) to 4.0% (95% CI: 3.1-5.2).

CONCLUSION

Bystander CPR was associated with a higher chance of 30-day survival among OHCA of presumed non-cardiac origin regardless of the underlying cause (medical/non-medical). Rates of bystander CPR and 30-day survival improved during the study period.

Molecular analysis of anthocyanin biosynthesis pathway genes and their differential expression in mango peel

Mango fruit is cherished by masses for its taste and nutrition, contributed by color, flavor, and aroma. Among these, peel color is an important trait contributing to fruit quality and market value. We attempted to elucidate the role of key genes of the anthocyanin biosynthesis pathway related to fruit peel color from the leaf transcriptome of mango cultivar Amrapali. A total of 108 mined transcript sequences were assigned to the phenylpropanoid-flavonoid pathway from which 15 contigs representing anthocyanin biosynthesis genes were annotated. Alternate splice variants were identified by mapping against genes of Citrus clementina and Vitis vinifera (closest relatives) and protein subcellular localization was determined. Phylogenetic analysis of these pathway genes clustered them into distinct groups aligning with homologous genes of Magnifera indica, C. clementina, and V. vinifera. Expression profiling revealed higher relative fold expressions in mature fruit peel of red-colored varieties (Arunika, Ambika, and Tommy Atkins) in comparison with the green-peeled Amrapali. MiCHS, MiCHI, and MiF3H alternate splice variants revealed differential gene expression. Functionally divergent variants indicate availability of an allelic pool programmed to play critical roles in peel color. This study provides insight into the molecular genetic basis of peel color and offers scope for development of biomarkers in varietal improvement programs.

Steroid administration after anaesthetic induction with etomidate does not reduce in-hospital mortality or cardiovascular morbidity after non-cardiac surgery

BACKGROUND

We tested the primary hypothesis that corticosteroid administration after etomidate exposure reduces a composite of in-hospital mortality and cardiovascular morbidity after non-cardiac surgery.

METHODS

We evaluated ASA physical status III and IV patients who had non-cardiac surgery with general anaesthesia at the Cleveland Clinic. Amongst 4275 patients in whom anaesthesia was induced with etomidate, 804 were also given steroid intraoperatively, mostly dexamethasone at a median dose of 6 mg. We successfully matched 582 steroid patients with 1023 non-steroid patients. The matched groups were compared on composite of in-hospital mortality and cardiovascular morbidity using a generalized-estimating-equation model. Secondly, the matched groups were compared on length of hospital stay using a Cox proportional hazard model, and were descriptively compared on intraoperative blood pressures using a standardized difference.

RESULTS

There was no significant association between intraoperative steroid administration after anaesthetic induction with etomidate and the composite of in-hospital mortality or cardiovascular morbidity; the estimated common odds ratio across the two components of the composite was 0.86 [95% confidence interval (CI): 0.64, 1.16] for steroid vs non-steroid, P=0.33. The duration of postoperative hospitalisation was significantly shorter amongst steroid patients [median (Q1, Q3): 6 (3, 10) days] than non-steroid patients [7 (4, 11) days], with an estimated hazard ratio of 0.89 (0.80, 0.98) for steroid vs non-steroid, P=0.01. Intraoperative blood pressures were similar in steroid and non-steroid patients.

CONCLUSIONS

Steroid administration after induction of anaesthesia with etomidate did not reduce mortality or cardiovascular morbidity.

Dichloro-naphthoquinone as a non-classical inhibitor of the mycobacterial carbonic anhydrase Rv3588c

The soluble mycobacterial carbonic anhydrases Rv3588c and Rv1284 belong to a different class of carbonic anhydrases than those found in humans, making them attractive drug targets by using the inherent differences in the folds of the different classes. By screening a natural product library, we identified naphthoquinone derivatives as a novel non-classical inhibitor scaffold of mycobacterial carbonic anhydrases that lack the sulfonamide/sulfamate group and thus did not affect human carbonic anhydrase II.

Guiding bispecific monovalent antibody formation through proteolysis of IgG1 single-chain

We developed an IgG1 domain-tethering approach to guide the correct assembly of 2 light and 2 heavy chains, derived from 2 different antibodies, to form bispecific monovalent antibodies in IgG1 format. We show here that assembling 2 different light and heavy chains by sequentially connecting them with protease-cleavable polypeptide linkers results in the generation of monovalent bispecific antibodies that have IgG1 sequence, structure and functional properties. This approach was used to generate a bispecific monovalent antibody targeting the epidermal growth factor receptor and the type I insulin-like growth factor receptor that: 1) can be produced and purified using standard IgG1 techniques; 2) exhibits stability and structural features comparable to IgG1; 3) binds both targets simultaneously; and 4) has potent anti-tumor activity. Our strategy provides new engineering opportunities for bispecific antibody applications, and, most importantly, overcomes some of the limitations (e.g., half-antibody and homodimer formation, light chains mispairing, multi-step purification), inherent with some of the previously described IgG1-based bispecific monovalent antibodies.

Biological and mechanical evaluation of a Bio-Hybrid scaffold for autologous valve tissue engineering

Major challenge in heart valve tissue engineering for paediatric patients is the development of an autologous valve with regenerative capacity. Hybrid tissue engineering approach is recently gaining popularity to design scaffolds with desired biological and mechanical properties that can remodel post implantation. In this study, we fabricated aligned nanofibrous Bio-Hybrid scaffold made of decellularized bovine pericardium: polycaprolactone-chitosan with optimized polymer thickness to yield the desired biological and mechanical properties. CD44⁺, αSMA⁺, Vimentin⁺ and CD105^- human valve interstitial cells were isolated and seeded on these Bio-Hybrid scaffolds. Subsequent biological evaluation revealed interstitial cell proliferation with dense extra cellular matrix deposition that indicated the viability for growth and proliferation of seeded cells on the scaffolds. Uniaxial mechanical tests along axial direction showed that the Bio-Hybrid scaffolds has at least 20 times the strength of the native valves and its stiffness is nearly 3 times more than that of native valves. Biaxial and uniaxial mechanical studies on valve interstitial cells cultured Bio-Hybrid scaffolds revealed that the response along the axial and circumferential direction was different, similar to native valves. Overall, our findings suggest that Bio-Hybrid scaffold is a promising material for future development of regenerative heart valve constructs in children.

Refugee child oral health

The number of people forced to flee their homes and move around the world is increasing rapidly. Such refugee populations are not only more likely to have poor physical, mental and social health outcomes but also to experience difficulties accessing health services in their new country. In particular, children from refugee backgrounds are at increased risk of poor oral health which in time is associated with poor adult oral health and impacts on child health (e.g. growth and development) and well-being. To date, there is little evidence about the nature and extent of their oral health problems nor interventions to improve their oral health status. This article summarises the evidence surrounding the oral health status of children from refugee backgrounds. In addition, a systematic review of the international literature over the past 10 years is presented which identifies interventions to improve the oral health of these vulnerable paediatric populations. Based on this evidence, potential strategies available to dental service providers to optimise provision of responsive dental care are discussed.

Perioperative factors associated with acute kidney injury after partial nephrectomy

BACKGROUND

Partial nephrectomy is performed with the aim to preserve renal function. But the occurrence of postoperative acute kidney injury (AKI) can interfere with this goal. Our primary aim was to evaluate associations between pre-specified modifiable factors and estimated glomerular filtration rate after partial nephrectomy. Our secondary aims were to evaluate associations between pre-specified modifiable factors and both serum creatinine concentration and type of nephrectomy.

METHODS

The records of 1955 patients who underwent partial nephrectomy were collected. Postoperative estimated glomerular filtration rate (eGFR) was used as the primary outcome measure. Twenty modifiable risk factors were studied. A repeated-measures linear model with autoregressive within-subject correlation structure was used. The interaction between all the factors and type of nephrectomy was also studied.

RESULTS

A total of 1187 (61%) patients had no kidney injury, 647 (33%) had stage I, 80 (4%) had stage II, and 41 (2%) had stage III injury. The mean eGFR increased an estimated 0.83 (99.76% CI 0.79-0.88) ml min(-1) 1.73 m(-2) for a unit increase in baseline eGFR. Mean eGFR was 2.65 (99.76% CI: 0.13, 5.18) ml min(-1) 1.73 m(-2) lower in patients with hypertension. Mean eGFR decreased 0.42 (99.76% CI: 0.22, 0.62) ml min(-1) 1.73 m(-2) for a 10-minute longer in duration of procedure and decreased 2.09 (99.76% CI: 1.39, 2.80) ml min(-1) 1.73 m(-2) for a 10-minute longer in ischemia time. It was 3.53 (99.76% CI: 0.83, 6.23) ml min(-1) 1.73 m(-2) lower for patients who received warm ischemia as compared to cold ischemia.

CONCLUSION

Potentially modifiable factors associated with AKI in the postoperative period were identified as baseline renal function, preoperative hypertension, longer duration of surgical time and ischaemia time, and warm ischaemia.

Variation of phytoplankton assemblages of Kongsfjorden in early autumn 2012: a microscopic and pigment ratio-based assessment

Phytoplankton species distribution and composition were determined by using microscopy and pigment ratios in the Kongsfjorden during early autumn 2012. Variation in sea surface temperature (SST) was minimal and matched well with satellite-derived SST. Nutrients were generally limited. Surface phytoplankton abundance ranged from 0.21 × 10(3) to 10.28 × 10(3) cells L(-1). Phytoplankton abundance decreased with depth and did not show any significant correlation with chlorophyll a (chl a). Column-integrated phytoplankton cell counts (PCC) ranged from 94.3 × 10(6) cells m(-2) (Kf4) to 13.7 × 10(6) cells m(-2) (Kf5), while chl a was lowest at inner part of the fjord (6.3 mg m(-2)) and highest towards the mouth (24.83 mg m(-2)). Biomass from prymnesiophytes and raphidophytes dominated at surface and 10 m, respectively. The contribution of Bacillariophyceae to biomass was low. Generally, heterotrophic dinoflagellates were great in abundance (12.82 %) and ubiquitous in nature and were major contributors to biomass. Various chl pigments (chl b, chl c, phaeopigments (phaeo)) were measured to obtain pigment/chl a ratios to ascertain phytoplankton composition. Phaeo were observed only in inner fjord. Chl b:a ratios and microscopic observations indicated dominance of Chlorophyceae at greater depths than surface. Furthermore, microscopic observations confirmed dominance of chl c containing algae throughout the fjord. The study indicates that pigment ratios can be used as a tool for preliminary identification of major phytoplankton groups. However, under the presence of a large number of heterotrophic dinoflagellates such as Gymnodinium sp. and Gyrodinium sp., pigment signatures need to be supplemented by microscopic observations.

Molecular and morphological diversity in locally grown non-commercial (heirloom) mango varieties of North India

Mango (Mangifera indica L.) has been cultivated and conserved in different agro-ecologies including Malihabad region in northern part of India, that is well known for housing diverse types (heirloom and commercial varieties). In the present study, 37 mango types comprising of 27 heirloom varieties from Malihabad region and 10 commercial varieties grown in North and Eastern India were assessed for morphological attributes and molecular diversity. The employed SSR markers amplified 2-13 alleles individually, cumulatively amplifying 124 alleles. These were studied for allelic diversity and genetic dissimilarity ranged from 0.035 to 0.892 arranging the varieties in three major clusters. The results revealed that majority of unique heirloom mangoes from Malihabad were different from the eastern part of the country. It is interesting to note Dashehari, a commercial variety from Malihabad was not aligned with heirloom varieties. Commercial varieties like Gulabkhas and Langra were placed in a separate group including Bombay Green, Himsagar, Dashehari, etc., indicating their dissimilarity with heirloom varieties at molecular level and thus, indicating importance for later from conservation point of view. Furthermore, the hierarchical clustering of varieties based on fruit morphology, assembled these into four groups largely influenced by fruit size. The maximum agreement subtree indicated seemingly good fit as thirteen varieties were arrayed in common grouping pattern. Appreciable dissimilarity among the heirloom varieties demonstrated by molecular analysis, underlines the importance for their on-farm conservation.

Abstract P3-01-06: Sentinel lymph node biopsy after NACT: Results of a validation study in large/locally advanced breast cancer patients

Background:

Sentinel lymph node biopsy (SLNB) is the current standard of care for surgical staging of clinically node negative axilla (N0) early breast cancer patients undergoing primary surgery. SLN- identification rate (IR) of 90% and SLN- false negative rate (FNR) of 10% are considered minimum acceptable indices for SLNB. Its role in staging axillae in patients undergoing post-NACT surgery is somewhat unclear. In India, and most low-and-middle income countries, large operable breast cancers (LOBC) and locally advanced breast cancers (LABC) constitute a large proportion of breast cancer patients treated. These patients are usually are treated with NACT, followed by surgery and radiation therapy. In a prospective validation SLNB study, we investigated the accuracy of SLNB in staging post-NACT N0 axilla in a patient cohort that were LOBC or LABC at the time of initial presentation.

Methods:

Hundred consenting non-inflammatory LOBC/LABC patients (mean age 49.3+8.6; index stage T3,N0-1=21; T4b,N0-1=33; T1-3,N2a=24; T4b,N2a=22) who were N0 after NACT at time of surgery (Breast conservation surgery in 19, Mastectomy in 81) were included. Majority had Infiltrating ductal carcinoma (n=87), and grade II/III tumors (n=93); 45 were hormone receptor positive (+), 29 had HR negative (-) HER2(+); and 26 had triple negative breast cancer on IHC sub-typing. Commonest NACT regimen used was Anthracycline followed by taxanes in 83. SLNB was performed using low-cost methylene-blue and 99mTc-Antimony-colloid, which were produced in-house using well standardized protocols, with clearance of the institutional ethics committee. Irrespective of the SLN histology, a complete axillary dissection (ALND) was carried out in all. SLN-IR and SLN-FNR were calculated, comparing the histological status of the SLN and the ALND specimen. Factors predicting non-identified SLN and false negative SLN were evaluated in uni-variate and multi-variate analysis.

Results:

With a combination of methylene blue dye and radiopharmaceutical, the SLN-IR was 81%. Mean number of SLN removed was 2.4+/-1.02. Mean number of nodes removed at ALND was 13.3+/-2.2. SLN-IR varied significantly (p&lt;0.05) per index stage, and were- 90.4% in T3,N0-1; 84.4% in T4b,N0-1; 83.3% in T1-3,N2a; and 63.6% in T4bN2a. The FNR was 17.3% for the whole cohort. FNR varied significantly (p&lt;0.05) per index stage, and were- 8.3% in T3,N0-1; 14.9% in T4b,N0-1; 22.2% in T1-3,N2a; and 30% in T4bN2a. Factors found predictive of non-identified SLN were tumor stage T4b, nodal stage N2a, extra-nodal spread, and LVI. Factors found predictive of FNR SLN were tumor stage T4b, nodal stage N2a, and extra-nodal spread.

Conclusions:

Considering SLN-IR of 90% and SLN-FNR of 10% as acceptable standards, SLNB in post-NACT N0 patients undergoing surgery was not found robust in staging the axilla, with the exception of patients with index stage T3,N0-1 who had SLN-IR of 90.4% and SLN-FNR of 8.3%. Patients with (pre-NACT) skin involvement(T4b), matted axillary nodes(N2a) and LVI are fraught with high-risk of non-identification and false-negative SLNB.

Citation Format: Agarwal G, Gambhir S, Lal P, Rajan S, Krishnani N, Mishra A, SabaRetnam M, Agarwal A, Chand G, Verma AK, Mishra SK, Kumari N, Agrawal V, Kheruka SC. Sentinel lymph node biopsy after NACT: Results of a validation study in large/locally advanced breast cancer patients. [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 P3-01-06.

Target-Agnostic Identification of Functional Monoclonal Antibodies Against Klebsiella pneumoniae Multimeric MrkA Fimbrial Subunit

The increasing incidence of Klebsiella pneumoniae infections refractory to treatment with current broad-spectrum antibiotic classes warrants the exploration of alternative approaches, such as antibody therapy and/or vaccines, for prevention and treatment. However, the lack of validated targets shared by spectrums of clinical strains poses a significant challenge. We adopted a target-agnostic approach to identify protective antibodies against K. pneumoniae Several monoclonal antibodies were isolated from phage display and hybridoma platforms by functional screening for opsonophagocytic killing activity. We further identified their common target antigen to be MrkA, a major protein in the type III fimbriae complex, and showed that these serotype-independent anti-MrkA antibodies reduced biofilm formation in vitro and conferred protection in multiple murine pneumonia models. Importantly, mice immunized with purified MrkA proteins also showed reduced bacterial burden following K. pneumoniae challenge. Taken together, these results support MrkA as a promising target for K. pneumoniae antibody therapeutics and vaccines.