Design and validation of an artificial intelligence system to detect the quality of colon cleansing before colonoscopy

BACKGROUND AND AIMS

Patients' perception of their bowel cleansing quality may guide rescue cleansing strategies before colonoscopy. The main aim of this study was to train and validate a convolutional neural network (CNN) for classifying rectal effluent during bowel preparation intake as "adequate" or "inadequate" cleansing before colonoscopy.

PATIENTS AND METHODS

Patients referred for outpatient colonoscopy were asked to provide images of their rectal effluent during the bowel preparation process. The images were categorized as adequate or inadequate cleansing based on a predefined 4-picture quality scale. A total of 1203 images were collected from 660 patients. The initial dataset (799 images), was split into a training set (80%) and a validation set (20%). The second dataset (404 images) was used to develop a second test of the CNN accuracy. Afterward, CNN prediction was prospectively compared with the Boston Bowel Preparation Scale (BBPS) in 200 additional patients who provided a picture of their last rectal effluent.

RESULTS

On the initial dataset, a global accuracy of 97.49%, a sensitivity of 98.17% and a specificity of 96.66% were obtained using the CNN model. On the second dataset, an accuracy of 95%, a sensitivity of 99.60% and a specificity of 87.41% were obtained. The results from the CNN model were significantly associated with those from the BBPS (P<0.001), and 77.78% of the patients with poor bowel preparation were correctly classified.

CONCLUSION

The designed CNN is capable of classifying "adequate cleansing" and "inadequate cleansing" images with high accuracy.

Inhibition of Retinoic Acid Signaling in Proximal Tubular Epithelial cells Protects against Acute Kidney Injury by Enhancing Kim-1-dependent Efferocytosis

Retinoic acid receptor (RAR) signaling is essential for mammalian kidney development, but in the adult kidney is restricted to occasional collecting duct epithelial cells. We now show there is widespread reactivation of RAR signaling in proximal tubular epithelial cells (PTECs) in human sepsis-associated acute kidney injury (AKI), and in mouse models of AKI. Genetic inhibition of RAR signaling in PTECs protects against experimental AKI but is associated with increased expression of the PTEC injury marker, Kim-1. However, Kim-1 is also expressed by de-differentiated, proliferating PTECs, and protects against injury by increasing apoptotic cell clearance, or efferocytosis. We show that the protective effect of inhibiting PTEC RAR signaling is mediated by increased Kim-1 dependent efferocytosis, and that this is associated with de-differentiation, proliferation, and metabolic reprogramming of PTECs. These data demonstrate a novel functional role that reactivation of RAR signaling plays in regulating PTEC differentiation and function in human and experimental AKI.

Graphical abstract

Assessing discards in an illegal small-scale fishery using fisher-led reporting

About a third of all marine fish in the world are caught in Small-Scale Fisheries (SSF). SSF are increasingly recognised as essential for food security and livelihoods for vulnerable and economically fragile communities globally. Although individual SSF vessels are usually perceived as having little impact on the ecosystem, the cumulative impact of gear type and number of vessels may be substantial. Bottom trawling is a common fishing method that can greatly influence the marine ecosystem by damaging the seafloor and generating high levels of discards. However, appropriate sampling coverage using on-board observer programmes to collect these data from SSF are rare, as they are expensive and pose logistical constraints. A mobile App was used to assess whether self-reporting by fishers could provide reliable fine-scale information on fishing effort and discards over time in an illegal shrimp trawling fishery in northern Peru. Maps depicting the spatial distribution of trawling effort and the proportion of discards from observers and fishers were compared using the Similarity in Means (SIM) Index, which ranges from 0 when spatial patterns differ completely to 1 when spatial patterns are very similar. High levels of agreement between spatio-temporal patterns of effort (SIM Index = 0.81) and discards (0.96) were found between fisher and observer maps. Moreover, far greater spatial coverage was accomplished by fishers, suggesting that self-reporting via an App represents a useful approach to collect reliable fisheries data as an initial step for effective monitoring and management of these fisheries.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11160-022-09708-9.

Comprehensive serological strategy for the diagnosis and monitoring of SARS-CoV-2. From infection to vaccine control

SARS-CoV-2 serology is useful to identify past COVID-19 cases, and it is not useful for acute infection. Levels of specific SARS-CoV-2 anti-N and especially anti-S are expected to be maintained for long periods. At this moment there is not a clear correlate of protection after COVID-19 or vaccination, therefore serological follow up is not indicated in most cases.

Recommendations for use of antigenic tests in the diagnosis of acute SARS-CoV-2 infection in the second pandemic wave: attitude in different clinical settings

The high transmissibility of SARS-CoV-2 before and shortly after the onset of symptoms suggests that only diagnosing and isolating symptomatic patients may not be sufficient to interrupt the spread of infection; therefore, public health measures such as personal distancing are also necessary. Additionally, it will be important to detect the newly infected individuals who remain asymptomatic, which may account for 50% or more of the cases. Molecular techniques are the "gold standard" for the diagnosis of SARS-CoV-2 infection. However, the massive use of these techniques has generated some problems. On the one hand, the scarcity of resources (analyzers, fungibles and reagents), and on the other the delay in the notification of results. These two facts translate into a lag in the application of isolation measures among cases and contacts, which favors the spread of the infection. Antigen detection tests are also direct diagnostic methods, with the advantage of obtaining the result in a few minutes and at the very "pointof-care". Furthermore, the simplicity and low cost of these tests allow them to be repeated on successive days in certain clinical settings. The sensitivity of antigen tests is generally lower than that of nucleic acid tests, although their specificity is comparable. Antigenic tests have been shown to be more valid in the days around the onset of symptoms, when the viral load in the nasopharynx is higher. Having a rapid and real-time viral detection assay such as the antigen test has been shown to be more useful to control the spread of the infection than more sensitive tests, but with greater cost and response time, such as in case of molecular tests. The main health institutions such as the WHO, the CDC and the Ministry of Health of the Government of Spain propose the use of antigenic tests in a wide variety of strategies to respond to the pandemic. This document aims to support physicians involved in the care of patients with suspected SC2 infection, in the context of a growing incidence in Spain since September 2020, which already represents the second pandemic wave of COVID-19.

Antiviral drugs targeting endosomal membrane proteins inhibit distant animal and human pathogenic viruses

The endocytic pathway is a common strategy that several highly pathogenic viruses use to enter into the cell. To demonstrate the usefulness of this pathway as a common target for the development of broad-spectrum antivirals, the inhibitory effect of drug compounds targeting endosomal membrane proteins were investigated. This study entailed direct comparison of drug effectiveness against animal and human pathogenic viruses, namely Ebola (EBOV), African swine fever virus (ASFV), and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

A panel of experimental and FDA-approved compounds targeting calcium channels and PIKfyve at the endosomal membrane caused potent reductions of entry up to 90% in SARS-CoV-2 S-protein pseudotyped retrovirus. Similar inhibition was observed against transduced EBOV glycoprotein pseudovirus and ASFV. SARS-CoV-2 infection was potently inhibited by selective estrogen receptor modulators in cells transduced with pseudovirus, among them Raloxifen inhibited ASFV with very low 50% inhibitory concentration. Finally, the mechanism of the inhibition caused by the latter in ASFV infection was analyzed.

Overall, this work shows that cellular proteins related to the endocytic pathway can constitute suitable cellular targets for broad range antiviral compounds.

Increasing the low residue diet to 3 days does not improve the bowel cleansing in hard to prepare patients: Post hoc analysis of a randomized controlled trial

BACKGROUND

Recent evidence suggests that the number of low residue diet (LRD) days does not influence the bowel cleansing quality in non-selected patients. However, there are not data in the subgroup of patients with risk factors of inadequate bowel cleansing.

OBJECTIVE

The aim of this study was to assess whether a 3-day LRD improved the bowel cleansing quality in patients with risk factors of poor bowel cleansing.

PATIENTS AND METHODS

Post hoc analysis of a randomized controlled trial carried out between December 2017 and March 2018 in a tertiary care hospital. Patients with high risk of poor bowel cleansing were selected following a validated score. The patients were randomized to the 1-day LRD or 3-day LRD groups. All patients received a 2-L split-dose of polyethylene glycol plus ascorbic acid. Intention-to-treat (ITT) and per-protocol (PP) analyses were conducted for the main outcome.

RESULTS

135 patients (1-day LRD group=67, 3-day LRD=68) were included. The rate of adequate cleansing quality was not significantly different between the groups in the ITT analysis: 76.1%, 95% CI: [64.6-84.8] vs. 79.4%, 95% CI: [68.2-87.4]; odds ratio (OR) 1.2, 95% CI [0.54-2.73]) or in the PP analysis: 77.3%, 95% CI: [65.7-85.8] vs. 80.3%, 95% CI: [69.0-88.3]; OR 1.2, 95% CI [0.52-2.77]). Compliance with the diet or cleansing solution, satisfaction or difficulties with the LRD and the polyp/adenoma detection rates were not significantly different.

CONCLUSION

Our results suggest that 1-day LRD is not inferior to 3-day LRD in patients with risk factors of inadequate bowel cleansing.

Impact of a 1-day versus 3-day low-residue diet on bowel cleansing quality before colonoscopy: a randomized controlled trial

BACKGROUND

The aim of this study was to assess whether a 3-day low-residue diet (LRD) improved bowel cleansing quality compared with a 1-day LRD regimen.

METHODS

Consecutive patients scheduled for outpatient colonoscopy were randomized to the 1-day LRD or 3-day LRD groups. All patients received a 2-L split-dose of polyethylene glycol plus ascorbic acid. The primary outcome was bowel cleansing quality as evaluated using the Boston Bowel Preparation Scale (BBPS) (adequate cleansing ≥ 2 points per segment). Secondary outcomes were adherence to and level of satisfaction with the LRD, difficulty following the dietary recommendations, and willingness to repeat the same LRD in the future. Intention-to-treat (ITT) and per-protocol (PP) analyses were conducted for the primary outcome. A superiority analysis was performed to demonstrate that a 3-day LRD regimen was superior to a 1-day LRD regimen with a margin of 10 %.

RESULTS

390 patients (1-day LRD group = 196, 3-day LRD = 194) were included. The cleansing quality was not significantly different between the groups: ITT analysis 82.7 % (95 % confidence interval [CI] 77.4 to 88.0) vs. 85.6 % (95 %CI 80.7 to 90.5), with odds ratio (OR) 1.2 (95 %CI 0.72 to 2.15); PP analysis 85.0 % (95 %CI 79.9 to 90.1) vs. 88.6 % (95 %CI 84.0 to 93.2), with OR 1.4 (95 %CI 0.88 to 2.52). No differences were found regarding adherence to the diet or cleansing solution, satisfaction or difficulty with the LRD, and the polyp/adenoma detection rates.

CONCLUSION

3-day LRD did not offer advantages over 1-day LRD in preparation for colonoscopy.

Application of metasurface-enhanced infra-red spectroscopy to distinguish between normal and cancerous cell types

Fourier transform infrared (FTIR) spectra of biological cells can reveal clinically important information about cells' composition, including their normal or cancerous status. The recently emerged diagnostic technique of spectral cytopathology (SCP) combines FTIR with multivariate statistical analysis to detect cell abnormalities, differentiate between cell types, and monitor disease progression. We demonstrate a new variant of SCP, a metasurface-enhanced infrared reflection spectroscopic cytopathology (MEIRSC) that utilises judiciously designed plasmonic metasurfaces to localize and enhance the evanescent field near the cell's membrane, and to carry out spectroscopic interrogations of the cells attached to the metasurface using reflected infrared light. Our findings indicate that the MEIRSC approach enables us to differentiate between normal and cancerous human colon cells. The sensitivity of MEIRSC is such that a very small (about 50 nm deep) portion of the cell can yield valuable diagnostic information.

In vitro caecal fermentation of carbohydrate-rich feedstuffs in rabbits as affected by substrate pre-digestion and donors' diet

The influence of substrate pre-digestion and donors’ diet on <em>in vitro</em> caecal fermentation of different substrates in rabbits was investigated. Eight crossbreed rabbits were fed 2 experimental diets containing either low (LSF; 84.0 g/kg dry matter [DM]) or high soluble fibre (HSF; 130 g/kg DM) levels. <em>In vitro</em> incubations were conducted using batch cultures with soft faeces as inoculum and four fibrous or fibre-derived, low-starch and low-protein substrates: D-cellobiose (CEL), sugar beet pectin (PEC), sugar beet pulp (SBP) and wheat straw (WS). Substrates in half of the cultures were subjected to a 2-step pepsin/pancreatin in vitro digestion without filtration, and the whole residue (soluble, insoluble and added enzymes) was incubated at 39°C. Gas production was measured until 144 h, and volatile fatty acid (VFA) production at 24 h incubation was determined. Cultures without substrate (blanks) were included to correct gas production values for gas released from endogenous substrates and added enzymes. Pre-digestion had no influence on <em>in vitro</em> gas production kinetic of WS, and only reduced the time before gas production begins (lag time; by 31%; P=0.042) for SBP, but for both substrates the pre-digestion decreased the molar proportion of acetate (by 9%; P≤0.003) and increased those of propionate and butyrate (P≤0.014). For CEL, the pre-digestion increased the gas and total VFA production (by 30 and 114%), shortened the lag time (by 32%), and only when it was combined with LSF inoculum 38 percentage units of acetate were replaced by butyrate (P≤0.039). Treatments had a minor influence on in vitro fermentation traits of SBP pectin. The results showed that the pre-digestion process influenced the in vitro caecal fermentation in rabbits, but the effects were influenced by donors’ diet and the incubated substrate. Pre-digestion of substrate is recommended before conducting <em>in vitro</em> caecal fermentations. The level of soluble fibre in the donors’ diet also influenced the <em>in vitro</em> caecal fermentation, but its effect depended on the type of substrate.

Comparison of the clinical course of Clostridium difficile infection in glutamate dehydrogenase-positive toxin-negative patients diagnosed by PCR to those with a positive toxin test

OBJECTIVES

To evaluate the potential role of PCR-based assays in the over-diagnosis of Clostridium difficile infection (CDI) by using a validated diagnostic algorithm in daily clinical practice.

METHODS

We performed a retrospective cohort study evaluating all C. difficile-positive stool samples identified at our institution during a 12-month period, to compare outcomes and recurrence rates between patients with a positive enzyme immunoassay (EIA) for both glutamate dehydrogenase (GDH) and toxin A/B ('toxin-positive group'), with those with GDH-positive, toxin-negative samples in whom the diagnosis was made by a positive PCR-based assay ('toxin^-/PCR⁺ group'). Medical records were reviewed by two independent investigators blinded to the mode of diagnosis.

RESULTS

We analysed 231 first CDI episodes (106 (45.8 %) in the 'toxin-positive group' and 125 (54.1%) in the 'toxin^-/PCR⁺ group'). Both groups had similar baseline characteristics. Patients in the 'toxin-positive group' presented more frequently with a severe/severe complicated form than those in the 'toxin^-/PCR⁺ group' (36 (33.9%) versus 24 (19.2%); p 0.011) and had more recurrences (27 (25.5%) versus 9 (7.2%); p 0.001). Diagnosis of CDI based on a GDH/toxin-positive EIA independently predicted severe/severe-complicated course (adjusted OR 2.11; 95% CI 1.06-4.22; p 0.033) and recurrence (adjusted OR 3.79; 95% CI 1.65-8.69; p 0.002). There were no differences in all-cause mortality (12.3% versus 12.0%; p 0.95) or CDI-attributable mortality (4.7% versus 4.8%; p 0.93).

CONCLUSIONS

Toxin-positive patients were more likely to have severe-complicated forms of CDI and recurrences. Nevertheless, CDI-related complications may still occasionally occur among toxin-negative patients diagnosed by PCR, which stresses the need for individualized clinical evaluation.

Total synthesis of malagashanine: a chloroquine potentiating indole alkaloid with unusual stereochemistry

The first total synthesis of malagashanine, a chloroquine potentiating indole alkaloid, is presented. A highly stereoselective cascade annulation reaction was developed to generate the tetracyclic core of the Malagasy alkaloids. This chemistry is likely to be broadly applicable to the synthesis of other members of this stereochemically unique family of natural products.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Methylphenidate amplifies long-term potentiation in rat hippocampus CA1 area involving the insertion of AMPA receptors by activation of β-adrenergic and D1/D5 receptors

Methylphenidate (MPH, Ritalin©) is widely used in the treatment of Attention Deficit Hyperactivity Disorder and recently as a drug of abuse. Although the effect of MPH has been studied in brain regions such as striatum and prefrontal cortex (PFC), the hippocampus has received relatively little attention. It is known that MPH increases the TBS-dependent Long Term Potentiation (LTP) in the CA1 area. However, the cellular and molecular mechanisms involved in this process are still unknown. Using field potential recordings and western blot analysis in rat hippocampal slices of young rats, we found that acute application of MPH enhances LTP in CA3-CA1 synapses in a dose-dependent manner with an EC50 of 73.44±6.32 nM. Using specific antagonists and paired-pulse facilitation protocols, we observed that the MPH-dependent increase of LTP involves not only β-adrenergic receptors activation but also post-synaptic D1/D5 dopamine receptors. The inhibition of PKA with PKI, suppressed the facilitation of LTP induced by MPH consistent with an involvement of the adenyl cyclase-cAMP-PKA dependent cascade downstream of the activation of D1/D5 receptors. In addition, samples of CA1 areas taken from slices potentiated with MPH presented an increase in the phosphorylation of the Ser845 residue of the GluA1 subunit of AMPA receptors compared to control slices. This effect was reverted by SCH23390, antagonist of D1/D5 receptors, and PKI. Moreover, we found an increase of surface-associated functional AMPA receptors. We propose that MPH increases TBS-dependent LTP in CA3-CA1 synapses through a polysynaptic mechanism involving activation of β-adrenergic and D1/D5 dopaminergic receptors and promoting the trafficking and insertion of functional AMPA receptors to the plasma membrane.

Cost-effectiveness of a Barcelona home care program for individuals with multimorbidity

To improve the efficiency and effectiveness of care and optimize healthcare resources, a home healthcare program was created for individuals with multiple chronic conditions. Demographic and clinical characteristics of the 261 individuals (mean age 84) included in the program from its inception in 2011 through 2013 (mean stay in the program 203±192 days) were prospectively analyzed. The number of hospital admissions, length of stay, and costs for individuals admitted to the program were compared for two time periods: the 6 months before admission to the program and their stay in the program. After admission to the program, the number of hospital admissions and the hospital length of stay per person per month decreased from 0.36±0.21 to 0.19±0.52 (P<.001) and from 3.5 to 1 day (P<.001), respectively. Surveys of randomly selected patients and caregivers showed high satisfaction with the program. Costs per person per day decreased from €54.65 (US$73.12) to €17.91 (US$23.96), a reduction of 67.1%. Fewer admissions and shorter hospital stays enabled the hospital to eliminate one acute bed for every 50 individuals admitted to the program. In conclusion, home care for individuals with chronic illness with multimorbidity reduced the number of hospital admissions and length of stay, resulting in good patient satisfaction and lower costs.

Estimating surface NO2 and SO2 mixing ratios from fast-response total column observations and potential application to geostationary missions

Total-column nitrogen dioxide (NO₂) data collected by a ground-based sun-tracking spectrometer system (Pandora) and an photolytic-converter-based in-situ instrument collocated at NASA's Langley Research Center in Hampton, Virginia were analyzed to study the relationship between total-column and surface NO₂ measurements. The measurements span more than a year and cover all seasons. Surface mixing ratios are estimated via application of a planetary boundary-layer (PBL) height correction factor. This PBL correction factor effectively corrects for boundary-layer variability throughout the day, and accounts for up to ≈75 % of the variability between the NO₂ data sets. Previous studies have made monthly and seasonal comparisons of column/surface data, which has shown generally good agreement over these long average times. In the current analysis comparisons of column densities averaged over 90 s and 1 h are made. Applicability of this technique to sulfur dioxide (SO₂) is briefly explored. The SO₂ correlation is improved by excluding conditions where surface levels are considered background. The analysis is extended to data from the July 2011 DISCOVER-AQ mission over the greater Baltimore, MD area to examine the method's performance in more-polluted urban conditions where NO₂ concentrations are typically much higher.

Use of cohort data to estimate national prevalence of transmitted drug resistance to antiretroviral drugs in Spain (2007-2012)

Prevalence of transmitted drug resistance (pTDR) to antiretroviral drugs in Spain (2007-2012) was estimated using the CoRIS cohort, adjusting its territorial distribution and transmission route to the reference population from the Spanish Information System on New human immunodeficiency virus diagnoses. A total of 2702 patients from ten autonomous communities and with naive FASTA sequence within 6 months of human immunodeficiency virus diagnosis were selected. Weighted pTDR, estimated using the inverse probability of selection in the sample by autonomous communities and transmission group, was 8.12% (95% CI 6.44-9.80), not significantly different from unweighted pTDR. We illustrate how proportional weighting can maximize representativeness of cohort-based data, and its value to monitor pTDR at country level.

Effects of a Mangifera indica L. stem bark extract and mangiferin on radiation-induced DNA damage in human lymphocytes and lymphoblastoid cells

OBJECTIVES

Mangifera indica L. (mango) stem bark aqueous extract (MSBE) that has antioxidant, anti-inflammatory and immunomodulatory properties, can be obtained in Cuba. It is rich in polyphenols, where mangiferin is the main component. In this study, we have tested DNA damage and protection effects of MSBE and mangiferin on primary human lymphocytes and lymphoblastoid cells.

MATERIAL AND METHODS

Cell suspensions were incubated with the products (50-1000 μg/ml) for experiments on damage induction, and evaluation of any potential protective effects (5-100 μg/ml) for 60 min at 37 °C. Irradiation was performed using a γ-ray source, absorbed dose 5 Gy. At the end of exposure, DNA damage, protection and repair processes were evaluated using the comet assay.

RESULTS

MSBE (100-1000 μg/ml) induced DNA damage in a concentration dependent manner in both cell types tested, primary cells being more sensitive. Mangiferin (200 μg/ml) only induced light DNA damage at higher concentrations. DNA repair capacity was not affected after MSBE or mangiferin exposure. On the other hand, MSBE (25 and 50 μg/ml) and mangiferin (5-25 ug/ml) protected against gamma radiation-induced DNA damage.

CONCLUSIONS

These results show MSBE has protector or harmful effects on DNA in vitro depending on the experimental conditions, which suggest that the extract could be acting as an antioxidant or pro-oxidant product. Mangiferin was involved in protective effects of the extract.