Notum produced by Paneth cells attenuates regeneration of aged intestinal epithelium.

A decline in stem cell function impairs tissue regeneration during ageing, but the role of the stem-cell-supporting niche in ageing is not well understood. The small intestine is maintained by actively cycling intestinal stem cells that are regulated by the Paneth cell niche1,2. Here we show that the regenerative potential of human and mouse intestinal epithelium diminishes with age owing to defects in both stem cells and their niche. The functional decline was caused by a decrease in stemness-maintaining Wnt signalling due to production of Notum, an extracellular Wnt inhibitor, in aged Paneth cells. Mechanistically, high activity of mammalian target of rapamycin complex 1 (mTORC1) in aged Paneth cells inhibits activity of peroxisome proliferator activated receptor α (PPAR-α)3, and lowered PPAR-α activity increased Notum expression. Genetic targeting of Notum or Wnt supplementation restored function of aged intestinal organoids. Moreover, pharmacological inhibition of Notum in mice enhanced the regenerative capacity of aged stem cells and promoted recovery from chemotherapy-induced damage. Our results reveal a role of the stem cell niche in ageing and demonstrate that targeting of Notum can promote regeneration of aged tissues.

Bartonella quintana Endocarditis: A Systematic Review of Individual Cases.

BACKGROUND: Bartonella quintana is a louse-borne bacterium that remains a neglected cause of endocarditis in low-resource settings. Our understanding of risk factors, clinical manifestations, and treatment of B. quintana endocarditis are biased by older studies from high-income countries. METHODS: We searched Pubmed Central, Medline, Scopus, Embase, EBSCO (CABI) Global Health, Web of Science and international trial registers for articles published before March 2023 with terms related to Bartonella quintana endocarditis. We included articles containing case-level information on B. quintana endocarditis and extracted data related to patient demographics, clinical features, diagnostic testing, treatment, and outcome. RESULTS: A total of 975 records were identified, of which 569 duplicates were removed prior to screening. In total, 84 articles were eligible for inclusion, describing a total of 167 cases. Infections were acquired in 40 different countries; 62 cases (37.1%) were acquired in low- and middle-income countries (LMICs). Disproportionately more female and pediatric patients were from LMICs. More patients presented with heart failure (n = 70/167 [41.9%]) than fever (n = 65/167 [38.9%]). Mean time from symptom onset to presentation was 5.1 months. Also, 25.7% of cases (n = 43/167) were associated with embolization, most commonly to the spleen and brain; 65.5% of antimicrobial regimens included doxycycline. The vast majority of cases underwent valve replacement surgery (n = 154/167, [98.0%]). Overall case fatality rate was 9.6% (n = 16/167). CONCLUSIONS: B. quintana endocarditis has a global distribution, and long delays between symptom onset and presentation frequently occur. Improved clinician education and diagnostic capacity are needed to screen at-risk populations and identify infection before endocarditis develops.

Ceftazidime-avibactam alone or in combination with Aztreonam versus Polymyxins in the management of carbapenem-Resistant Klebsiella pneumoniae nosocomial Infections (CAPRI study): a retrospective cohort study from South India.

INTRODUCTION: Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections commonly cause hospital-acquired infections. The study aimed to compare the outcomes of CRKP infections between patients receiving ceftazidime avibactam +/- aztreonam and polymyxins in a hospital setting with a high prevalence of New Delhi Metallo Beta Lactamase production. METHODS: We conducted a retrospective cohort study from January 2020 to September 2022 in critically ill adult patients admitted to a non-COVID-19 medical intensive care unit with CRKP infection. The patients were followed up for a total of 30 days or death, whichever was later. RESULTS: Of a total of 106 patients included in the study, 65 patients received polymyxins and 41 patients received ceftazidime-avibactam +/- aztreonam. Higher 30-day mortality was noted in the polymyxin group (56.9% vs. 29.2%, P = 0.005). The mean time to event (mortality) in ceftazidime-avibactam +/- aztreonam was 23.9 + 1.5 days which was significantly higher compared to polymyxins (17.9 + 1.2 days, p = 0.006). On Cox regression analysis, after adjusting for the covariates, the hazard ratio for time to event with the use of polymyxin was 2.02 (95% CI: 1.03-3.9). CONCLUSION: Ceftazidime-avibactam + aztreonam is possibly associated with better clinical outcomes in patients infected with CRKP.

Author Correction: High-fat diet enhances stemness and tumorigenicity of intestinal progenitors.

In Fig. 4e of this Article, the labels for 'Control' and 'HFD' were reversed ('Control' should have been labelled blue rather than purple, and 'HFD' should have been labelled purple rather than blue). Similarly, in Fig. 4f of this Article, the labels for 'V' and 'GW' were reversed ('V' should have been labelled blue rather than purple, and 'GW' should have been labelled purple instead of blue). The original figure has been corrected online.

Emergence of Mycobacterium orygis-Associated Tuberculosis in Wild Ruminants, India.

Tuberculosis caused by Mycobacterium orygis was detected in 2 spotted deer from a wildlife sanctuary in western India and an Indian bison from a national park in central India. Nationwide surveillance is urgently required to clarify the epidemiology of the Mycobacterium tuberculosis complex at the human-livestock-wildlife interface.

Doxycycline vs azithromycin in patients with scrub typhus: a systematic review of literature and meta-analysis.

INTRODUCTION: Scrub typhus is a bacterial mite-borne disease associated with poor clinical outcomes if not treated adequately. The study aimed to compare the time to defervescence, clinical failure, mortality and treatment-related adverse effects of two common drugs (doxycycline and azithromycin) used for its treatment. METHODOLOGY: This was a systematic review and meta-analysis. All studies up to 20.03.2023 were screened for eligibility in Pubmed and Embase using a search string containing terms related to scrub typhus, doxycycline and azithromycin. After two phases of screening, all comparative studies where doxycycline and azithromycin were used to treat scrub typhus were included. The studies were critically appraised using standardised tools, and a meta-analysis was performed for time to defervescence (primary outcome), clinical failure, mortality and treatment-related adverse effects. RESULTS: Of 744 articles from two databases, ten were included in the meta-analysis. All but two studies had a high risk of bias. The meta-analysis for time to defervescence had a high heterogeneity and did not show any significant difference between doxycycline and azithromycin arms [Mean difference of -3.37 hours (95%CI: -10.31 to 3.57), p=0.34]. When the analysis was restricted to studies that included only severe scrub typhus, doxycycline was found to have a shorter time to defervescence [mean difference of -10.15 (95%CI: -19.83 to -0.46) hours, p=0.04]. Additionally, there was no difference between the two arms concerning clinical failure, mortality and treatment-related adverse effects. CONCLUSION: The current data from studies with a high risk of bias did not find statistically significant differences in clinical outcomes between doxycycline and azithromycin for scrub typhus.

An Unguided, Computerized Cognitive Behavioral Therapy Intervention (TreadWill) in a Lower Middle-Income Country: Pragmatic Randomized Controlled Trial.

BACKGROUND: Globally, most individuals who are susceptible to depression do not receive adequate or timely treatment. Unguided computerized cognitive behavioral therapy (cCBT) has the potential to bridge this treatment gap. However, the real-world effectiveness of unguided cCBT interventions, particularly in low- and middle-income countries (LMICs), remains inconclusive. OBJECTIVE: In this study, we aimed to report the design and development of a new unguided cCBT-based multicomponent intervention, TreadWill, and its pragmatic evaluation. TreadWill was designed to be fully automated, engaging, easy to use, and accessible to LMICs. METHODS: To evaluate the effectiveness of TreadWill and the engagement level, we performed a double-blind, fully remote, and randomized controlled trial with 598 participants in India and analyzed the data using a completer's analysis. RESULTS: The users who completed at least half of the modules in TreadWill showed significant reduction in depression-related (P=.04) and anxiety-related (P=.02) symptoms compared with the waitlist control. Compared with a plain-text version with the same therapeutic content, the full-featured version of TreadWill showed significantly higher engagement (P=.01). CONCLUSIONS: Our study provides a new resource and evidence for the use of unguided cCBT as a scalable intervention in LMICs. TRIAL REGISTRATION: ClinicalTrials.gov NCT03445598; https://clinicaltrials.gov/ct2/show/NCT03445598.

Coinfection of leptospirosis and coronavirus disease 2019: A retrospective case series from a coastal region in South India.

During the monsoon season of 2020, the coastal areas of South India were endemic to both leptospirosis and coronavirus disease 2019 (COVID-19). This study aimed to investigate the clinical features and outcomes of patients infected with both infections. A retrospective review of charts of all patients with COVID-19 who were also diagnosed with leptospirosis by immunoglobulin M enzyme-linked immunosorbent assay was undertaken. The clinical features, laboratory report, treatment details, and outcomes of all the included patients were recorded. The collected data were summarized as the frequency with percentage for categorical data and the mean or median for continuous data. Twenty-four cases of coinfections were admitted between July and November 2020. Most of these patients were categorized as severe COVID-19 (n = 15, 62.5%). Acute kidney injury was seen in 79.2% (n = 19) patients, while raised bilirubin was present in 79.2% (n = 19) of the patients. All patients had raised C-reactive protein, while all but one had raised procalcitonin. Thrombocytopenia, leucocytosis, and leukocytopenia were seen in 91.7% (n = 22), 45.8% (n = 11), and 12.5% (n = 3) of the patients. The median duration of hospital stay was 11 (8.25-15) days. A total of 79.2% (n = 19) of the patients improved and were discharged, while 20.8% (n = 5) died during the hospital stay. In conclusion, patients with fever and atypical manifestations such as hepatic dysfunction, renal dysfunction, and thrombocytopenia should be evaluated for leptospirosis even if they are COVID positive.

Efficacy of antiviral therapies for COVID-19: a systematic review of randomized controlled trials.

BACKGROUND: Coronavirus disease 2019 (COVID-19) continues to pose a significant threat to public health worldwide. The purpose of this study was to review current evidence obtained from randomized clinical trials on the efficacy of antivirals for COVID-19 treatment. METHODS: A systematic literature search was performed using PubMed to identify randomized controlled trials published up to September 4, 2021 that examined the efficacy of antivirals for COVID-19 treatment. Studies that were not randomized controlled trials or that did not include treatment of COVID-19 with approved antivirals were excluded. Risk of bias was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) method. Due to study heterogeneity, inferential statistics were not performed and data were expressed as descriptive statistics. RESULTS: Of the 2,284 articles retrieved, 31 (12,440 patients) articles were included. Overall, antivirals were more effective when administered early in the disease course. No antiviral treatment demonstrated efficacy at reducing COVID-19 mortality. Sofosbuvir/daclatasvir results suggested clinical improvement, although statistical power was low. Remdesivir exhibited efficacy in reducing time to recovery, but results were inconsistent across trials. CONCLUSIONS: Although select antivirals have exhibited efficacy to improve clinical outcomes in COVID-19 patients, none demonstrated efficacy in reducing mortality. Larger RCTs are needed to conclusively establish efficacy.

High-fat diet enhances stemness and tumorigenicity of intestinal progenitors.

Little is known about how pro-obesity diets regulate tissue stem and progenitor cell function. Here we show that high-fat diet (HFD)-induced obesity augments the numbers and function of Lgr5(+) intestinal stem cells of the mammalian intestine. Mechanistically, a HFD induces a robust peroxisome proliferator-activated receptor delta (PPAR-δ) signature in intestinal stem cells and progenitor cells (non-intestinal stem cells), and pharmacological activation of PPAR-δ recapitulates the effects of a HFD on these cells. Like a HFD, ex vivo treatment of intestinal organoid cultures with fatty acid constituents of the HFD enhances the self-renewal potential of these organoid bodies in a PPAR-δ-dependent manner. Notably, HFD- and agonist-activated PPAR-δ signalling endow organoid-initiating capacity to progenitors, and enforced PPAR-δ signalling permits these progenitors to form in vivo tumours after loss of the tumour suppressor Apc. These findings highlight how diet-modulated PPAR-δ activation alters not only the function of intestinal stem and progenitor cells, but also their capacity to initiate tumours.

Molecular characterization of Clostridioides difficile by multi-locus sequence typing (MLST): A study from tertiary care center in India.

OBJECTIVES: Clostridioides difficile is an important pathogen responsible for antibiotic-associated diarrhoea (AAD). This study was aimed to perform multi-locus sequence typing (MLST) of C. difficile isolates from AAD cases and to understand the clonal relationship between these C. difficile strains. METHODS: Thirty five strains and a standard strain C.difficile ATCC 9689 were characterized by polymerase chain reaction assay (PCR) for toxin genes (tcdA and tcdB gene) detection and MLST. RESULTS: MLST results revealed that the most common sequence types were ST-17, ST-54, ST-63. The cluster analysis revealed that strains isolated from AAD patients generated 12 MLST sequence types grouped into two distinct evolutionary lineages. CONCLUSIONS: ST 17 is most prominent sequence type. This is the first report of MLST based study of C. difficile from India. Further studies from diverse geographical regions can help better understand the epidemiology of CDI in India.

Utility of the One-time HACOR Score as a Predictor of Weaning Failure from Mechanical Ventilation: A Prospective Observational Study.

Aim: To determine the utility of the HACOR score in predicting weaning failure in resource-limited settings. Objectives: The primary objective was to determine a cut-off value of the HACOR score, sensitivity, and specificity to predict failed weaning. The secondary objective was to determine which out of five components of the score was significantly different between the successful weaning and the failed weaning groups. Introduction: Most weaning indices are either inaccurate or are dependent on complex ventilatory parameters, which are difficult to measure in resource-limited settings. This study aimed to determine the utility of the HACOR score consisting of heart rate, acidosis, consciousness level, oxygenation, and respiratory rate as a predictor of weaning in the intensive care unit. Materials and methods: It was a prospective observational study on 120 patients between 18 and 90 years. The HACOR score was evaluated at 30 minutes of spontaneous breathing trial (SBT). The total duration of SBT was 120 minutes. Results: Out of 120 patients, 83 (69.2%) had successful weaning, whereas 37 (30.8%) had weaning failure. The median and interquartile range (IQR) of the HACOR score in the successful weaning group was 2 (0-3) and 6 (5-8) in the failed weaning group (p-value <0.001). There was a significant difference in each of the five components of the HACOR score between the successful and failed weaning groups (p <0.05). HACOR score ≥5 predicted failed weaning, sensitivity 83.8%, specificity 96.4%, area under the curve (AUC) 0.950, and 95% confidence interval (CI) [0.907-0.993], p <0.001. Multivariable logistic regression analysis showed that HACOR score ≥5 is an independent predictor of weaning failure [p <0.001, 95% CI (1.9-4.2), adjusted odds ratio 2.82]. Conclusion: A HACOR score ≥5 is an excellent predictor of weaning failure. This score may be useful as a weaning strategy in the intensive care unit. How to cite this article: Chaudhuri S, Gupta N, Adhikari SD, Todur P, Maddani SS, Rao S. Utility of the One-time HACOR Score as a Predictor of Weaning Failure from Mechanical Ventilation: A Prospective Observational Study. Indian J Crit Care Med 2022;26(8):900-905. Ethical approval: Prior to the commencement of the study, Institutional Ethics Committee permission was obtained (IEC: 197/2021) and Clinical Trial Registry of India (CTRI) registration was done before recruitment (CTRI/2021/07/035139). We obtained written informed consent from the legally authorized representative prior to recruiting patients for the study.

Clinical Profile, Treatment, and Outcome of Patients with Secondary Hemophagocytic Lymphohistiocytosis in Critically Ill Patients: A Prospective Observational Study.

Introduction: The objective of the study was to evaluate the clinical profile and outcome of patients with secondary hemophagocytic lymphohistiocytosis (HLH) in critically ill patients. Materials and methods: A prospective observational study was conducted where critically ill adult patients presenting with fever and bicytopenia were evaluated according to the HLH-2004 diagnostic criteria for the presence of secondary HLH. The underlying trigger, clinical profile, treatment, and outcome of patients with HLH were analyzed. Results: Of the 76 critically ill patients with fever and bicytopenia, 33 (43%) patients were diagnosed with HLH. The following triggers for HLH were identified: bacterial infections (23%), fungal infections (10%), viral infections (10%), parasitic infections (10%), autoimmune diseases (13%), and malignancy (8%). A total of 78% of the HLH cases received steroids, but the use of steroids was not associated with improvement in mortality. Conclusion: There is a high prevalence of HLH in patients presenting with fever and bicytopenia in critically ill adult patients. Infections were identified as the most common trigger of HLH. How to cite this article: Fazal F, Gupta N, Soneja M, Mitra DK, Satpathy G, Panda SK, et al. Clinical Profile, Treatment, and Outcome of Patients with Secondary Hemophagocytic Lymphohistiocytosis in Critically Ill Patients: A Prospective Observational Study. Indian J Crit Care Med 2022;26(5):564-567.

Comparison of effect of etomidate with propofol on hemodynamics during modified electroconvulsive therapy.

Background and Aims: Studies comparing the effect of propofol and etomidate on hemodynamic parameters during electroconvulsive therapy (ECT) have shown ambiguous results. Although some studies observed a larger increase in blood pressure and heart rate during the use of etomidate than propofol in ECT, whereas some studies have shown no difference in hemodynamic parameters with the use of etomidate or propofol. Most of the studies done to compare the hemodynamic effects of etomidate and propofol were limited by small sample size or retrospective in nature. Therefore, we conducted a prospective randomized trial to compare the effects of etomidate and propofol on hemodynamics during ECT. Material and Methods: A prospective randomized crossover study was conducted on 30 patients with American Society of Anesthesiologist physical status I and II, between age 18 and 65 years, suffering from a mental disorder as per International Classification of Diseases-10 and requiring bilateral ECT as per clinical decision of consultant psychiatrist. They were randomized to receive both the drugs for their successive ECT sessions and were subjected to evaluation after clubbing together the ECT sessions of propofol or etomidate as anesthetic agent. Results: Duration of motor seizures was significantly more in patients receiving etomidate, whereas patients receiving propofol had more stable hemodynamics. Conclusion: Though propofol maintains stable hemodynamics during MECT, yet clinical applicability of etomidate outstrips it by a reasonable margin due to its better effect on seizure parameters.

Impact of microbial contamination of haematopoietic stem cells on post-transplant outcomes: A retrospective study from tertiary care centre in India.

BACKGROUND: Haematopoietic stem cells (HSC) may act as a source of infection for the recipient due to manipulation at multiple levels from collection to infusion. Due to the high risk of contamination cultures are usually taken during multiple steps. The clinical significance of microbial contamination of HSC on the post-transplant course and the role of prophylactic antibiotics is relatively unknown. AIMS AND METHODS: The aim of our study is to investigate the incidence of microbial contamination of haematopoietic stem cell and to assess its impact on the post-transplant febrile neutropenia, engraftment kinetics, hospitalisation and day 100 mortality. Details of all patients admitted in the bone marrow transplantation unit of a tertiary care centre in India between January 2014 and December 2018 were collected from case records. RESULTS: Of the 1306 stem cell harvests from 503 patients sent for culture, 17 harvests (1.3%) were found to have a culture positive report. Sixteen patients had undergone autologous transplant. Multiple myeloma was most common indication of HSC transplant followed by Non-Hodgkin Lymphoma (NHL). Twelve of 17 HSC cultures were positive at the time of infusion and five were positive at the time of harvest. The five HSC that were culture positive at the time of harvest were culture negative at the time of infusion. Gram-positive organisms were isolated in six cultures and gram-negative in rest. All patients developed febrile neutropenia post-transplantation between day 1 and day 7. The median time of onset of fever was day +5 (1-7), the median duration of fever was 4 days (2-7), the median duration of antibiotic use was 11 days (9-16). Median day for neutrophil engraftment was 11 days (9-16), the median day for platelet engraftment was 14 days (10-25) and median duration of hospitalisation was 15 days (12-78). All patients were alive at day 100 of transplant. CONCLUSION: This study shows that there appears to be minimal impact of culture positive HSC on transplant related outcomes in terms of engraftment kinetics, duration of hospitalisation and day 100 mortality. Discarding of contaminated HSC may not be required, though on development of febrile neutropenia appropriate antibiotics should be administered based on sensitivity pattern of HSC culture. Larger prospective studies are needed to determine the clinical relevance of such contaminations. Emphasis should be laid on better infection control practices to minimise contamination rates.

Efficacy of convalescent plasma therapy for COVID-19: A systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis was to examine clinical outcomes associated with convalescent plasma therapy in COVID-19 patients. We performed a literature search on PubMed, medRxiv, Web of Science, and Scopus to identify studies published up to December 10th, 2020 that examined the efficacy of convalescent plasma treatment for COVID-19. The primary endpoints were mortality, clinical improvement, and hospital length of stay. We screened 859 studies that met the search criteria, performed full-text reviews of 56 articles, and identified 15 articles that fulfilled inclusion criteria for meta-analysis. The odds of mortality were significantly lower in the convalescent plasma group compared to the control group (OR = 0.59 [95% CI = 0.44; 0.78], P < .001), although results from two key randomized controlled trials did not support the mortality benefit. The odds of clinical improvement were significantly higher in the convalescent plasma group compared to the control group (OR = 2.02 [95% CI = 1.54; 2.65], P < .001). There was no difference in hospital length of stay between the convalescent plasma group and the control group (MD = -0.49 days [95% CI = -3.11; 2.12], P = .713). In all, these data indicate that a mortality benefit with convalescent plasma is unclear, although there remain benefits with convalescent plasma therapy for COVID-19.

Transmission of SARS-CoV-2 Infection by Children: A Study of Contacts of Index Paediatric Cases in India.

The susceptibility of children to coronavirus disease-19 (COVID-19) and transmission of COVID-19 from children to others is a relatively unexplored area. The aim of this study was to understand the transmission dynamics of Severe Acute Respiratory Syndrome Coronavirus 2 in children. This was a retrospective observational study where a total of 19 paediatric index cases (including a set of twins) with COVID-19 and 42 primary contacts (adults-36, paediatric-6) from the immediate family members were included. All the index cases and four of the five positive contacts were asymptomatic. Despite adults staying with positive children in the same vehicle, same room in the quarantine centre and the same ward, only four of the parents became positive.

Neutrophil-Lymphocyte Ratio in Patients with COVID-19 as a Simple Tool to Predict Requirement of Admission to a Critical Care Unit.

INTRODUCTION: Coronavirus disease-2019 (COVID-19) pandemic has overloaded the healthcare system beyond its functional capacity. Late referral to higher levels of care may be one of the factors associated with higher mortality. Therefore, we aimed to find simple demographic and laboratory parameters which predict the requirement of admission to a critical care unit. MATERIALS AND METHODS: A case-control study was undertaken in adult age population >18 years, admitted in a dedicated COVID hospital in South India. A total of 50 patients with severe disease (cases) were compared with 143 mild or asymptomatic cases (controls). Those demographic and laboratory parameters that were found to be significant on univariate analysis were used for multiple logistic regression analysis. RESULTS: Univariate analysis of demographic and laboratory data showed higher age, male sex, presence of diabetes mellitus, higher values of C-reactive protein, ferritin, D-dimer, neutrophil-lymphocyte ratio (NLR), and lactate dehydrogenase to be significantly associated with cases. Multivariate logistic regression analysis of these significant variables showed NLR and ferritin to be the independent predictors of the requirement of admission to a critical care unit. The receiver-operating characteristic curve showed an NLR value of 5.2 and a ferritin value of 462 µg/L that were able to predict the requirement of admission in critical care units. CONCLUSION: High ferritin and NLR were independent predictors of the requirement of admission in critical care units. NLR is a simple tool that can be used in resource-limited settings for triage and early referral to higher levels of care. HOW TO CITE THIS ARTICLE: Maddani SS, Gupta N, Umakanth S, Joylin S, Saravu K. Neutrophil-Lymphocyte Ratio in Patients with COVID-19 as a Simple Tool to Predict Requirement of Admission to a Critical Care Unit. Indian J Crit Care Med 2021;25(5):535-539.

Development and Validation of Clinical Scoring Tool to Predict Outcomes of Treatment With Vedolizumab in Patients With Ulcerative Colitis.

BACKGROUND & AIMS: We created and validated a clinical decision support tool (CDST) to predict outcomes of vedolizumab therapy for ulcerative colitis (UC). METHODS: We performed logistic regression analyses of data from the GEMINI 1 trial, from 620 patients with UC who received vedolizumab induction and maintenance therapy (derivation cohort), to identify factors associated with corticosteroid-free remission (full Mayo score of 2 or less, no subscore above 1). We used these factors to develop a model to predict outcomes of treatment, which we called the vedolizumab CDST. We evaluated the correlation between exposure and efficacy. We validated the CDST in using data from 199 patients treated with vedolizumab in routine practice in the United States from May 2014 through December 2017. RESULTS: Absence of exposure to a tumor necrosis factor (TNF) antagonist (+3 points), disease duration of 2 y or more (+3 points), baseline endoscopic activity (moderate vs severe) (+2 points), and baseline albumin concentration (+0.65 points per 1 g/L) were independently associated with corticosteroid-free remission during vedolizumab therapy. Patients in the derivation and validation cohorts were assigned to groups of low (CDST score, 26 points or less), intermediate (CDST score, 27-32 points), or high (CDST score, 33 points or more) probability of vedolizumab response. We observed a statistically significant linear relationship between probability group and efficacy (area under the receiver operating characteristic curve, 0.65), as well as drug exposure (P < .001) in the derivation cohort. In the validation cohort, a cutoff value of 26 points identified patients who did not respond to vedolizumab with high sensitivity (93%); only the low and intermediate probability groups benefited from reducing intervals of vedolizumab administration due to lack of response (P = .02). The vedolizumab CDST did not identify patients with corticosteroid-free remission during TNF antagonist therapy. CONCLUSIONS: We used data from a trial of patients with UC to develop a scoring system, called the CDST, which identified patients most likely to enter corticosteroid-free remission during vedolizumab therapy, but not anti-TNF therapy. We validated the vedolizumab CDST in a separate cohort of patients in clinical practice. The CDST identified patients most likely to benefited from reducing intervals of vedolizumab administration due to lack of initial response. ClinicalTrials.gov no: NCT00783718.

Plasmonic nanoantennas on VO2 films for active switching of near-field intensity and radiation from nanoemitters.

In this paper, we propose novel plasmonic switches based on plasmonic nanoantennas lying on top of a thin film of a phase change material such as vanadium dioxide (VO2), such that the near-field properties of these nanoantennas can be actively switched by varying the phase of the VO2 film. We employ finite difference time domain (FDTD) simulations to first demonstrate that the near-field intensity in the vicinity of the plasmonic nanoantennas can be substantially switched by changing the phase of the vanadium dioxide film from the semiconductor state to the metallic state. We demonstrate that a ring-bowtie nanoantenna (RBN) switch can switch the near-field intensity by ∼ 59.5 times and ring-rhombus nanoantenna (RRN) switch can switch the near-field intensity by a factor of ∼ 80.8. These values of the maximum intensity switching ratios are substantially higher than those previously reported in the literature. In addition, we optimize the various geometrical parameters of the plasmonic switches to maximize the intensity switching ratio and to understand how the different parameters affect the performance of the plasmonic switches. In this paper, we also show that the intensity of emission from a nanoemitter placed in the gap between the two arms of a plasmonic nanoantenna can be significantly switched by changing the phase of the VO2 film between its semiconductor state and the metallic state. To quantify the switching of emission from the nanoemitters placed in the near-field of the nanoantennas, we define and calculate a parameter, called FESR, the ratio of fluorescent enhancement factors in the on-state and off-state of the plasmonic switch. The maximum fluorescence enhancement switching ratio (FESR) of ∼ 163 is obtained for the RBN switch and FESR of ∼ 200 is obtained for RRN switch. The plasmonic switches being proposed by us can be easily fabricated by employing the conventional nanofabrication and thin film deposition processes.