Navigating the waves in Colombia: a cohort study of inpatient care during four COVID-19 waves

INTRODUCTION

Understanding the intricate dynamics between different waves of the COVID-19 pandemic and the corresponding variations in clinical outcomes is essential for informed public health decision-making. Comprehensive insights into these fluctuations can guide resource allocation, healthcare policies, and the development of effective interventions. This study aimed to compare the characteristics and clinical outcomes of COVID-19 at peak transmission points by including all patients attended during the first four pandemic waves in a referral center in Colombia.

MATERIAL AND METHODS

In a prospective observational study of 2733 patients, clinical and demographic data were extracted from the Fundacion Valle de Lili's COVID-19 Registry, focusing on ICU admission, Invasive Mechanical Ventilation (IMV), length of hospital stay, and mortality.

RESULTS

Our analysis unveiled substantial shifts in patient care patterns. Notably, the proportion of patients receiving glucocorticoid therapy and experiencing secondary infections exhibited a pronounced decrease across waves (p < 0.001). Remarkably, there was a significant reduction in ICU admissions (62.83% vs. 51.23% vs. 58.23% vs. 46.70 %, p < 0.001), Invasive Mechanical Ventilation (IMV) usage (39.25% vs. 32.22% vs. 31.22% vs. 21.55 %, p < 0.001), and Length of Hospital Stay (LOS) (9 vs. 8 vs. 8 vs. 8 days, p < 0.001) over the successive waves. Surprisingly, hospital mortality remained stable at approximately 18‒20 % (p > 0.05). Notably, vaccination coverage with one or more doses surged from 0 % during the initial waves to 66.71 % in the fourth wave.

CONCLUSIONS

Our findings emphasize the critical importance of adapting healthcare strategies to the evolving dynamics of the pandemic. The reduction in ICU admissions, IMV utilization, and LOS, coupled with the rise in vaccination rates, underscores the adaptability of healthcare systems. Hospital mortality's persistence may warrant further exploration of treatment strategies. These insights can inform public health responses, helping policymakers allocate resources effectively and tailor interventions to specific phases of the pandemic.

Estimación de la eficiencia del uso de pabellones electivos en el sistema de salud público chileno entre 2018 y 2021

Objective

The efficient use of wards intended for elective surgeries is essential to resolve cases on the surgical waiting list. This study aims to estimate the efficiency of ward use in the Chilean public health system between 2018 and 2021.

Methods

The design was an ecological study. Section A.21 of the database constructed by the monthly statistical summaries that each public health network facility reported to the Ministry of Health between 2018 and 2021 was analyzed. Data from subsections A, E and F were extracted: ward staffing, total elective surgeries by specialty, number and causes of suspension of elective surgeries. Then, the surgical performance during working hours and the percentage of hourly occupancy for a working day was estimated. Additionally, an analysis was made by region with data from 2021.

Results

The percentage of elective wards in use ranged from 81.1% to 94.1%, while those enabled for those staffing ranged from 70.5% to 90.4% during 2018 and 2021. The total number of surgeries was highest in 2019 (n = 416 339), but for 2018, 2020, and 2021 it ranged from 259 000 to 297 000. Suspensions varied between 10.8% (2019) and 6.9% (2021), with the leading cause being patient-related. When analyzing the number of cases canceled monthly by facility, we saw that the leading cause was trade union-related. The maximum throughput of a ward intended for elective surgery was reached in 2019 and was 2.5 surgeries; in 2018, 2020 and 2021, the throughput borders on two surgeries per ward enabled for elective surgery. The percentage of ward time occupied during working hours by contract day varies between 80.7% (2018) and 56.8% (2020).

Conclusions

All the parameters found and estimated in this study show that there is an inefficient utilization of operating rooms in Chilean public healthcare facilities.

Flavin-Conjugated Pt(IV) Anticancer Agents

In situ activation of Pt(IV) to Pt(II) species is a promising strategy to control the anticancer activity and overcome the off-target toxicity linked to classic platinum chemotherapeutic agents. Herein, we present the design and synthesis of two new asymmetric Pt(IV) derivatives of cisplatin and oxaliplatin (1·TARF and 2·TARF, respectively) bearing a covalently bonded 2',3',4',5'-tetraacetylriboflavin moiety (TARF). ¹H and ¹⁹⁵Pt NMR spectroscopy shows that 1·TARF and 2·TARF can be effectively activated into toxic Pt(II) species, when incubated with nicotinamide adenine dinucleotide, sodium ascorbate, and glutathione in the dark and under light irradiation. Density functional theory studies of the dark Pt(IV)-to-Pt(II) conversion of 2·TARF indicate that the process involves first hydride transfer from the donor to the flavin moiety of the complex, followed by electron transfer to the Pt(IV) center. When administered to MDA-MB-231 breast cancer cells preincubated with nontoxic amounts of ascorbate, 2·TARF displays enhanced toxicity (between 1 and 2 orders of magnitude), suggesting that the generation of oxaliplatin can selectively be triggered by redox activation. Such an effect is not observed when 2 and TARF are coadministered under the same conditions, demonstrating that covalent binding of the flavin to the Pt complex is pivotal.

Engineered flavoproteins as bioorthogonal photo-triggers for the activation of metal-based anticancer prodrugs

A multifunctional hybrid constructed for controlling the delivery and activation of Pt anticancer agents in vitro is described herein. We employed consensus tetratricopeptide repeat protein (CTPR) for the covalent co-anchoring of riboflavin (photocatalyst) and a Pt(IV) prodrug complex. The Pt-loaded flavoprotein induced a 40% reduction in PANC-1 cell viability as a result of the photocatalytic formation of cisplatin.

Clinical Validation of Siemens' Syngo.via Automatic Contouring System

Purpose

The manual delineation of organs at risk is a process that requires a great deal of time both for the technician and for the physician. Availability of validated software tools assisted by artificial intelligence would be of great benefit, as it would significantly improve the radiation therapy workflow, reducing the time required for segmentation. The purpose of this article is to validate the deep learning-based autocontouring solution integrated in syngo.via RT Image Suite VB40 (Siemens Healthineers, Forchheim, Germany).

Methods and Materials

For this purpose, we have used our own specific qualitative classification system, RANK, to evaluate more than 600 contours corresponding to 18 different automatically delineated organs at risk. Computed tomography data sets of 95 different patients were included: 30 patients with lung, 30 patients with breast, and 35 male patients with pelvic cancer. The automatically generated structures were reviewed in the Eclipse Contouring module independently by 3 observers: an expert physician, an expert technician, and a junior physician.

Results

There is a statistically significant difference between the Dice coefficient associated with RANK 4 compared with the coefficient associated with RANKs 2 and 3 (P < .001). In total, 64% of the evaluated structures received the maximum score, 4. Only 1% of the structures were classified with the lowest score, 1. The time savings for breast, thorax, and pelvis were 87.6%, 93.5%, and 82.2%, respectively.

Conclusions

Siemens' syngo.via RT Image Suite offers good autocontouring results and significant time savings.

Access to knee arthroplasty among National Health Fund beneficiaries in Chile between 2004 and 2021

Introduction: Knee osteoarthritis affects the quality of life, with knee arthroplasty being a cost-effective treatment for the severe stage of this disease. Access to knee arthroplasty is a health indicator of the Organisation for Economic Co-operation and Development. The objectives of this study are to determine the incidence of knee arthroplasty between 2004 and 2021 in beneficiaries of the National Health Fund in Chile, the proportion of patients who underwent surgery in the private system, and to estimate the patient's out-of-pocket expenditure for surgery. Methods: Cross-sectional study. We used the Department of Statistics and Health Information database. Patients discharged from a Chilean health center who underwent knee arthroplasty surgery between 2004 and 2021 were investigated. We analyzed the proportion of patients by their National Health Fund category and whether their surgery was performed in public or private network facilities. Results: Of the 31 526 knee arthroplasty procedures, 21 248 (67.38%) were performed on National Health Fund patients and 16 238 in public institutions (51.49%). Patients from the National Health Fund showed a systematic increase in knee arthroplasty volume until 2019 but decreased in 2020 and 2021 by 68% and 51%. Of the total number of patients in the public system operated on for knee arthroplasty, 856 (9%) belonged to group A1, 12 806 (60%) to group B, 2044 (10%) to group C, and 4421 (21%) to group D. The expenditure incurred by these patients was estimated to vary between 24.4% and 27.2%. The historical proportions of access to this surgery in private institutions are 7% in group A, 13% in group B, 24% in group C, and 52% in group D. Conclusion: Fifty percent of knee arthroplasty surgeries are performed in public institutions, and two-thirds are performed on patients of the National Health Fund. Forty-six percent of the C and D groups were operated in the private system. The pandemic has increased the access gap, leading to a substantial increase in the proportion of patients from the National Health Fund of the B, C, and D groups who have migrated to the private system to access this surgery.

Impact of COVID-19 outbreak in knee arthroplasty in Chile: a cross-sectional, national registry-based analysis

Introduction The need for beds and health personnel to treat coronavirus (COVID- 19) patients has led to the suspension of many elective sur-geries in Chile, including knee arthroplasties. This study aims to determine the incidence of knee arthroplasty in 2020, reflecting the effect of the COVID- 19 pandemic, and estimate the cost and time it would take to recover the waiting list prior to March 2020. Methods A cross- sectional study was designed. We analyzed databases from The Department of Statistics and Health Information databases from Chile for 2019 and 2020, identifying patients with surgical discharges associated with knee arthroplasty codes. We estimated the time it would take to recover the surgeries unperformed in 2020 by simulating a monthly workload increase from the 2019 baseline. The costs of knee arthroplasty paid by the National Health Fund to institutions were estimated by diagnosis-related groups. Results We found that the incidence rate of knee arthroplasty in 2020 decreased by 64% compared with 2019. The impact was higher in the public system (68%) and the National Health Found (63%). A simulated increase in knee arthroplasty productivity by 30% would allow recovering the postponed knee arthroplasty surgeries in 27 months, at a monthly cost to the public system of 318 million Chilean pesos (378 thousand US dollars). Conclusions The incidence rate of knee arthroplasty during 2020 decreased by 64%, revealing the extensive waiting line for people with knee osteoarthritis. An increase between 20- 40% in productivity compared with 2019 would allow recovering the unperformed surgeries in 20 to 41 months, at a monthly cost to the public network between 210 and 425 million Chilean pesos (250 to 506 thousand US dollars). 10.5867/medwave.2022.04.002511 https://www.medwave.cl/link.cgi/English/Reviews/Analysis/8732.act Reflections on death in the time of Covid-19 Donovan Casas Patiño The pandemic of COVID- 19 filled the world with sorrow as death was an ever- present menace everywhere. This document aims to rescue some reflective facts about death marked by a socio- historical context that revealed breaking points. These points work around three specific aspects: the agony of the dying, funeral and religious rituals, and the pilgrimage between doubt and guilt. Death in times of pandemic revealed the need to humanize and guarantee a dignified death. Likewise, the pandemic reinvented funeral rituals by globalizing them using technology and social networks. Finally, we saw that the pilgrimage preludes death and awakens the most negative feelings in the face of rejection and frustration.

Impact of COVID-19 outbreak in knee arthroplasty in Chile: a cross-sectional, national registry-based analysis

Introduction

The need for beds and health personnel to treat coronavirus (COVID- 19) patients has led to the suspension of many elective sur-geries in Chile, including knee arthroplasties. This study aims to determine the incidence of knee arthroplasty in 2020, reflecting the effect of the COVID- 19 pandemic, and estimate the cost and time it would take to recover the waiting list prior to March 2020.

Methods

A cross- sectional study was designed. We analyzed databases from The Department of Statistics and Health Information databases from Chile for 2019 and 2020, identifying patients with surgical discharges associated with knee arthroplasty codes. We estimated the time it would take to recover the surgeries unperformed in 2020 by simulating a monthly workload increase from the 2019 baseline. The costs of knee arthroplasty paid by the National Health Fund to institutions were estimated by diagnosis-related groups.

Results

We found that the incidence rate of knee arthroplasty in 2020 decreased by 64% compared with 2019. The impact was higher in the public system (68%) and the National Health Found (63%). A simulated increase in knee arthroplasty productivity by 30% would allow recovering the postponed knee arthroplasty surgeries in 27 months, at a monthly cost to the public system of 318 million Chilean pesos (378 thousand US dollars).

Conclusions

The incidence rate of knee arthroplasty during 2020 decreased by 64%, revealing the extensive waiting line for people with knee osteoarthritis. An increase between 20- 40% in productivity compared with 2019 would allow recovering the unperformed surgeries in 20 to 41 months, at a monthly cost to the public network between 210 and 425 million Chilean pesos (250 to 506 thousand US dollars).

Landomycins as glutathione-depleting agents and natural fluorescent probes for cellular Michael adduct-dependent quinone metabolism

Landomycins are angucyclines with promising antineoplastic activity produced by Streptomyces bacteria. The aglycone landomycinone is the distinctive core, while the oligosaccharide chain differs within derivatives. Herein, we report that landomycins spontaneously form Michael adducts with biothiols, including reduced cysteine and glutathione, both cell-free or intracellularly involving the benz[a]anthraquinone moiety of landomycinone. While landomycins generally do not display emissive properties, the respective Michael adducts exerted intense blue fluorescence in a glycosidic chain-dependent manner. This allowed label-free tracking of the short-lived nature of the mono-SH-adduct followed by oxygen-dependent evolution with addition of another SH-group. Accordingly, hypoxia distinctly stabilized the fluorescent mono-adduct. While extracellular adduct formation completely blocked the cytotoxic activity of landomycins, intracellularly it led to massively decreased reduced glutathione levels. Accordingly, landomycin E strongly synergized with glutathione-depleting agents like menadione but exerted reduced activity under hypoxia. Summarizing, landomycins represent natural glutathione-depleting agents and fluorescence probes for intracellular anthraquinone-based angucycline metabolism.

Mobile microscopy and telemedicine platform assisted by deep learning for the quantification of Trichuris trichiura infection

Soil-transmitted helminths (STH) are the most prevalent pathogens among the group of neglected tropical diseases (NTDs). The Kato-Katz technique is the diagnosis method recommended by the World Health Organization (WHO) although it often presents a decreased sensitivity in low transmission settings and it is labour intensive. Visual reading of Kato-Katz preparations requires the samples to be analyzed in a short period of time since its preparation. Digitizing the samples could provide a solution which allows to store the samples in a digital database and perform remote analysis. Artificial intelligence (AI) methods based on digitized samples can support diagnosis by performing an objective and automatic quantification of disease infection. In this work, we propose an end-to-end pipeline for microscopy image digitization and automatic analysis of digitized images of STH. Our solution includes (a) a digitization system based on a mobile app that digitizes microscope samples using a 3D printed microscope adapter, (b) a telemedicine platform for remote analysis and labelling, and (c) novel deep learning algorithms for automatic assessment and quantification of parasitological infections by STH. The deep learning algorithm has been trained and tested on 51 slides of stool samples containing 949 Trichuris spp. eggs from 6 different subjects. The algorithm evaluation was performed using a cross-validation strategy, obtaining a mean precision of 98.44% and a mean recall of 80.94%. The results also proved the potential of generalization capability of the method at identifying different types of helminth eggs. Additionally, the AI-assisted quantification of STH based on digitized samples has been compared to the one performed using conventional microscopy, showing a good agreement between measurements. In conclusion, this work has presented a comprehensive pipeline using smartphone-assisted microscopy. It is integrated with a telemedicine platform for automatic image analysis and quantification of STH infection using AI models.

The Biotin-Avidin Interaction in Biotinylated Gold Nanoparticles and the Modulation of Their Aggregation

The biotin-avidin interaction is used as a binding tool for the conjugation of biomolecules for more diverse applications; these include nanoparticle conjugation. Despite this, a thorough investigation on the different aggregates that may result from the interaction of biotinylated nanoparticles (gold nanoparticles, AuNPs, in this work) with avidin has not been carried out so far. In this paper, we address this problem and show the type of aggregates formed under thermodynamic and kinetic control by varying the biotinylated AuNP/avidin ratio and the order of addition of the two partners. The analysis was performed by also addressing the amount of protein able to interact with the AuNPs surface and is fully supported by the TEM images collected for the different samples and the shift of the surface plasmon resonance band. We show that the percentage of saturation depends on the size of the nanoparticles, and larger nanoparticles (19 nm in diameter) manage to accommodate a relatively larger amount of avidins than smaller ones (11 nm). The AuNPs are isolated or form small clusters (mostly dimers or trimers) when a large excess or a very low amount of avidin is present, respectively, or form large clusters at stoichiometric concentration of the protein. Daisy-like systems are formed under kinetic control conditions when nanoparticles first covered with the protein are treated with a second batch of biotinylated ones but devoid of avidin.

Toward supramolecular nanozymes for the photocatalytic activation of Pt(IV) anticancer prodrugs

A supramolecular nanozyme for the photocatalytic conversion of a Pt(iv) anticancer complex to cisplatin is described herein. We employed 1.9 nm Au nanoparticles decorated with thiol ligands bearing a TACN (1,4,7-triazacyclononane) headgroup to encapsulate FMN (riboflavin-5'-phosphate). In the presence of an electron donor, flavin-loaded nanoparticles photocatalyzed the reductive activation of the prodrug cis,cis,trans-[Pt(NH3)2(Cl2)(O2CCH2CH2COOH)2] to cisplatin, achieving turnover frequency values of 7.4 min-1.

Evolutionary dynamics at the tumor edge reveal metabolic imaging biomarkers

Human cancers are biologically and morphologically heterogeneous. A variety of clonal populations emerge within these neoplasms and their interaction leads to complex spatiotemporal dynamics during tumor growth. We studied the reshaping of metabolic activity in human cancers by means of continuous and discrete mathematical models and matched the results to positron emission tomography (PET) imaging data. Our models revealed that the location of increasingly active proliferative cellular spots progressively drifted from the center of the tumor to the periphery, as a result of the competition between gradually more aggressive phenotypes. This computational finding led to the development of a metric, normalized distance from 18F-fluorodeoxyglucose (18F-FDG) hotspot to centroid (NHOC), based on the separation from the location of the activity (proliferation) hotspot to the tumor centroid. The NHOC metric can be computed for patients using 18F-FDG PET-computed tomography (PET/CT) images where the voxel of maximum uptake (standardized uptake value [SUV]max) is taken as the activity hotspot. Two datasets of 18F-FDG PET/CT images were collected, one from 61 breast cancer patients and another from 161 non-small-cell lung cancer patients. In both cohorts, survival analyses were carried out for the NHOC and for other classical PET/CT-based biomarkers, finding that the former had a high prognostic value, outperforming the latter. In summary, our work offers additional insights into the evolutionary mechanisms behind tumor progression, provides a different PET/CT-based biomarker, and reveals that an activity hotspot closer to the tumor periphery is associated to a worst patient outcome.

Incidence, risk factors and case fatality rate for hip fracture in Chile: A cross-sectional study based on 2017 national registries

Purpose

To describe the incidence of hip fracture in Chile during 2017, identify risk factors for in-hospital mortality, and estimate annual case fatality rate.

Method

The study design was cross-sectional and analytical. We obtained the registries of all patients from the Chilean Ministry of Health who were treated for hip fracture between January 1, 2017, and December 31, 2017. We used multivariate logistic regression to estimate the risk factors for in-hospital mortality. The annual case fatality rate was calculated using the probabilities obtained by estimating a logistic regression model in previous work. The estimated crude mortality rate per 100 000 persons was compared with that of cancer, as reported by the Ministry of Health.

Results

During 2017, 7421 hip fractures occurred, resulting in an incidence of 40 per 100 000 persons. Of these, 1574 (21.21%) cases did not undergo surgery. In-hospital mortality was found to be associated with no surgery (odds ratio 8.32, 6.20 to 11.17), and being treated in a public hospital (odds ratio 1.62, 1.00 to 2.68). The estimated annual case fatality rate was 0.30 (0.27 to 0.33), and the crude mortality rate per 100 000 persons was 10.78 (9.66 to 11.71).

Conclusion

Hip fractures mainly affect the population over 60 years old and women. Chile has an excessively high rate of non-operated patients compared to international reports. There is a significant difference between care in a public hospital compared to private clinics in terms of volume, access to surgery, hospital stay, in-hospital mortality, and estimated case fatality rate.

Identification and functional analysis of missense mutations in the lecithin cholesterol acyltransferase gene in a Chilean patient with hypoalphalipoproteinemia

Background

Lecithin-cholesterol acyltransferase (LCAT) is a plasma enzyme that esterifies cholesterol in high- and low-density lipoproteins (HDL and LDL). Mutations in LCAT gene causes familial LCAT deficiency, which is characterized by very low plasma HDL-cholesterol levels (Hypoalphalipoproteinemia), corneal opacity and anemia, among other lipid-related traits. Our aim is to evaluate clinical/biochemical features of a Chilean family with a proband showing clinical signs of familial LCAT deficiency, as well as to identify and assess the functional effects of LCAT mutations.

Methods

An adult female proband with hypoalphalipoproteinemia, corneal opacity and mild anemia, as well as her first-degree relatives, were recruited for clinical, biochemical, genetic, in-silico and in-vitro LCAT analysis. Sequencing of exons and intron-exon boundaries was performed to identify mutations. Site-directed mutagenesis was carried out to generate plasmids containing cDNA with wild type or mutant sequences. Such expression vectors were transfected to HEK-239 T cells to asses the effect of LCAT variants in expression, synthesis, secretion and enzyme activity. In-silico prediction analysis and molecular modeling was also used to evaluate the effect of LCAT variants.

Results

LCAT sequencing identified rare p.V333 M and p.M404 V missense mutations in compound heterozygous state in the proband, as well the common synonymous p.L363 L variant. LCAT protein was detected in proband’s plasma, but with undetectable enzyme activity compared to control relatives. HEK-293 T transfected cells with vector expression plasmids containing either p.M404 V or p.V333 M cDNA showed detectable LCAT protein expression both in supernatants and lysates from cultured cells, but with much lower enzyme activity compared to cells transfected with the wild-type sequence. Bioinformatic analyses also supported a causal role of such rare variations in LCAT lack of function. Additionally, the proband carried the minor allele of the synonymous p.L363 L variant. However, this variant is unlikely to affect the clinical phenotype of the proband given its relatively high frequency in the Chilean population (4%) and its small putative effect on plasma HDL-cholesterol levels.

Conclusion

Genetic, biochemical, in vitro and in silico analyses indicate that the rare mutations p.M404 V and p.V333 M in LCAT gene lead to suppression of LCAT enzyme activity and cause clinical features of familial LCAT deficiency.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-1045-0) contains supplementary material, which is available to authorized users.

Glucosamine Phosphate Induces AuNPs Aggregation and Fusion into Easily Functionalizable Nanowires

The challenge to obtain plasmonic nanosystems absorbing light in the near infrared is always open because of the interest that such systems pose in applications such as nanotherapy or nanodiagnostics. Here we describe the synthesis in an aqueous solution devoid of any surfactant of Au-nanowires of controlled length and reasonably narrow dimensional distribution starting from Au-nanoparticles by taking advantage of the properties of glucosamine phosphate under aerobic conditions and substoichiometric nanoparticle passivation. Oxygen is required to enable the process where glucosamine phosphate is oxidized to glucosaminic acid phosphate and H2O2 is produced. The process leading to the nanosystems comprises nanoparticles growth, their aggregation into necklace-like aggregates, and final fusion into nanowires. The fusion requires the consumption of H2O2. The nanowires can be passivated with an organic thiol, lyophilized, and resuspended in water without losing their dimensional and optical properties. The position of the broad surface plasmon band of the nanowires can be tuned from 630 to >1350 nm.

Anxiety and Depression in Patients Hospitalized With Chronic Kidney Disease in Barranquilla Clinics, Colombia

The purpose of this study is to determine the levels of anxiety and depression in patients aged between 18 and 70 years, hospitalized with chronic kidney disease in a clinic entity of the city of Barranquilla. The type of research is descriptive, presenting the information through the indicators and statistical tables, the Hospital Scale of Anxiety and Depression of, Zigmond &amp; Smith (1983), which evaluates the detection of depressive and anxious disorders in the non-psychiatric hospital context. The application of the Scale was performed in the hospital entity of the city of Barranquilla to 50 patients with Chronic Kidney Disease. The results they are beneficial in the short term, because they create new research proposals applied to another population group diagnosed with chronic diseases, especially for the evaluation and intervention in the area of health psychology. In the long term, new theories, methods of intervention and evaluation applied to the population of patients with chronic kidney disease will be studied. In the same way, the results show marked trends related to depression, an aspect that is consistent with the deterioration that affects the individual in the course of the disease and also show a positive correlation of the study variables, depression and anxiety disorders in patients with CKD can be due to a symptomatology or consequence of psychological burnout.

Enabling tomography with low-cost C-arm systems

In scenarios where the use of a Computed Tomography (CT) is difficult, such as during surgery or in the ICU, the use of a C-arm system to generate tomographic information could contribute with interesting additional clinical information. Recent days are seeing the development of the so-called cone-beam CT (CBCT) based on advanced motorized isocentric C-arm systems. To be able to make use of more basic C-arm systems, apart from the geometric non-idealities common to any CBCT, we need to address other difficulties. First, the trajectory of the source-detector pair may differ from a circular path and the system may suffer mechanical strains that modify the relative positions of the source and detector for different projection angles. Second, and more importantly, the exact position of the source and detector elements may not be repeatable for consecutive rotations due to low mechanical precision, thus preventing an accurate geometrical calibration of the system. Finally, the limitation of the angular span and the difficulty of obtaining a high number of projections pose a great challenge to the image reconstruction. In this work, we present a novel method to adapt a standard C-arm, originally designed for planar imaging, to be used as a tomograph. The key parts of the new acquisition protocol are (1) a geometrical calibration method to compensate mechanical inaccuracies that prevent an accurate repetition of source-detector position between acquisitions, and (2) an advanced image reconstruction method able to deal with limited angle data, sparse projections and non-circular trajectories. Both methods exploit surface information from the patient, which can be obtained using a 3D surface scanner. The proposed method was evaluated with two real C-arm systems, based on an image intensifier and a flat panel detector respectively, showing the feasibility of the proposal.

Clinical impact of mineralocorticoid receptor antagonists treatment after acute coronary syndrome in the real world: A propensity score matching analysis

BACKGROUND

Recent studies suggest that the benefit of mineralocorticoid receptor antagonists in the acute coronary syndrome setting is controversial. The aim of this study was to examine the current long-term prognostic benefit of mineralocorticoid receptor antagonists in patients with acute coronary syndrome.

MATERIAL AND METHODS

We conducted a retrospective cohort study of 8318 consecutive acute coronary syndrome patients. Baseline patient characteristics were examined and a follow-up period was established for registry of death, major cardiovascular adverse events and heart failure re-hospitalization. We performed a propensity-matching analysis to draw up two groups of patients paired according to whether or not they had been treated with mineralocorticoid receptor antagonists. The prognostic value of mineralocorticoid receptor antagonists to predict events during follow-up was analysed using Cox regression.

RESULTS

Among the study participants, only 524 patients (6.3%) were discharged on mineralocorticoid receptor antagonists. Patients on mineralocorticoid receptor antagonists had a different clinical and pharmacological profile. These differences disappeared after the propensity score analysis. The median follow-up was 40.7 months. After the propensity score analysis, the cardiovascular mortality and heart failure readmission rates were similar between patients who were discharged on mineralocorticoid receptor antagonists and those whose not. The use of mineralocorticoid receptor antagonists was only associated with a reduction in major cardiovascular adverse events (hazard ratio=0.83, 95% confidence interval 0.69-0.97, p=0.001).

CONCLUSIONS

Our results do not corroborate the long-term benefit of mineralocorticoid receptor antagonists to improve survival after acute coronary syndrome in a large cohort of patients with heart failure or reduced left ventricular ejection fraction and diabetes. Their prescription was associated with a significantly lower incidence of major cardiovascular adverse events during the long-term follow-up without effect on heart failure development.

Determinants and Prognostic Impact of Heart Failure and Left Ventricular Ejection Fraction in Acute Coronary Syndrome Settings

INTRODUCTION AND OBJECTIVES

Contemporary data on the incidence and prognosis of heart failure (HF) and the influence of left ventricular ejection fraction (LVEF) in the setting of acute coronary syndrome (ACS) are scant. The aim of this study was to examine the relationship between LVEF and HF with long-term prognosis in a cohort of patients with ACS.

METHODS

This is a retrospective observational study of 6208 patients consecutively admitted for ACS to 2 different Spanish hospitals. Baseline characteristics were examined and a follow-up period was established for registration of death and HF rehospitalization as the primary endpoint.

RESULTS

Among the study participants, 5064 had ACS without HF during hospitalization: 290 (5.8%) had LVEF<40%, 540 (10.6%) LVEF 40% to 49%, and 4234 (83.6%) LVEF ≥ 50%. The remaining 1144 patients developed HF in the acute phase: 395 (34.6%) had LVEF<40%, 251 (21.9%) LVEF 40% to 49%, and 498 (43.5%) LVEF ≥ 50%. Patients with LVEF 40% to 49% had a demographic and clinical profile with intermediate features between the LVEF <40% and LVEF ≥ 50% groups. Kaplan-Meier curves showed that mortality and HF readmissions were statistically different depending on LVEF in the non-HF group but not in the HF group. Left ventricular ejection fraction ≥ 50% was an independent prognostic factor in the non-HF group only.

CONCLUSIONS

In ACS, long-term prognosis is considerably worse in patients who develop HF during hospitalization than in patients without HF, irrespective of LVEF. This parameter is a strong prognostic predictor only in patients without HF.

Amphiphilic oligoethyleneimine-β-cyclodextrin "click" clusters for enhanced DNA delivery

Monodisperse amphiphilic oligoethyleneimine (OEI)-β-cyclodextrin (βCD) clusters have been prepared, and their potential as gene delivery systems has been evaluated in comparison with a nonamphiphilic congener. The general prototype incorporates tetraethyleneimine segments linked to the primary rim of βCD through either triazolyl or thioureidocysteaminyl connectors. Transfection efficiency data for the corresponding CD:pDNA nanocomplexes (CDplexes) in BNL-CL2 murine hepatocytes evidenced the strong beneficial effect of facial amphiphilicity.

Cyclodextrin-based multivalent glycodisplays: covalent and supramolecular conjugates to assess carbohydrate-protein interactions

Covalent attachment of biorecognizable sugar ligands in several copies at precise positions of cyclomaltooligosaccharide (cyclodextrin, CD) macrocycles has proven to be an extremely flexible strategy to build multivalent conjugates. The commercial availability of the native CDs in three different sizes, their axial symmetry and the possibility of position- and face-selective functionalization allow a strict control of the valency and spatial orientation of the recognition motifs (glycotopes) in low, medium, high and hyperbranched glycoclusters, including glycodendrimer-CD hybrids. "Click-type" ligation chemistries, including copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC), thiol-ene coupling or thiourea-forming reactions, have been implemented to warrant full homogeneity of the adducts. The incorporation of different glycotopes to investigate multivalent interactions in heterogeneous environments has also been accomplished. Not surprisingly, multivalent CD conjugates have been, and continue to be, major actors in studies directed at deciphering the structural features ruling carbohydrate recognition events. Nanometric glycoassemblies endowed with the capability of adapting the inter-saccharide distances and orientations in the presence of a receptor partner or capable of mimicking the fluidity of biological membranes have been conceived by multitopic inclusion complex formation, rotaxanation or self-assembling. Applications in the fields of sensors, site-specific drug and gene delivery or protein stabilization attest for the maturity of the field.

Polycationic amphiphilic cyclodextrins as gene vectors: effect of the macrocyclic ring size on the DNA complexing and delivery properties

A collection of homologous monodisperse facial amphiphiles consisting of an α-, β- or γ-cyclodextrin (α, β or γCD) platform exposing a multivalent display of cationic groups at the primary rim and bearing hexanoyl chains at the secondary hydroxyls have been prepared to assess the influence of the cyclooligosaccharide core size in their ability to complex, compact and protect pDNA and in the efficiency of the resulting nanocondensates (CDplexes) to deliver DNA into cells and promote transfection in the presence of serum. All the polycationic amphiphilic CDs (paCDs) were able to self-assemble in the presence of the plasmid and produce transfectious nanoparticles at nitrogen/phosphorous ratios ≥5. CDplexes obtained from βCD derivatives generally exhibited higher transfection capabilities, which can be ascribed to their ability to form inclusion complexes with cholesterol, thereby enhancing biological membrane permeability. The presence of thiourea moieties as well as increasing the number of primary amino groups then favour cooperative complexation of the polyphosphate chain, enhancing the stability of the complex and improving transfection. In the α and γCD series, however, only the presence of tertiary amino groups in the cationic clusters translates into a significant improvement of the transfection efficiency, probably by activating endosome escape by the proton sponge mechanism. This set of results illustrates the potential of this strategy for the rational design and optimisation of nonviral gene vectors.