Is it possible to predict the severity of acute appendicitis? Reliability of predictive models based on easily available blood variables.

INTRODUCTION: Recent evidence confirms that the treatment of acute appendicitis is not necessarily surgical, and selected patients with uncomplicated appendicitis can benefit from a non-operative management. Unfortunately, no cost-effective test has been proven to be able to effectively predict the degree of appendicular inflammation as yet, therefore, patient selection is too often left to the personal choice of the emergency surgeon. Our paper aims to clarify if basic and readily available blood tests can give reliable prognostic information to build up predictive models to help the decision-making process. METHODS: Clinical notes of 2275 patients who underwent an appendicectomy with a presumptive diagnosis of acute appendicitis were reviewed, taking into consideration basic preoperative blood tests and histology reports on the surgical specimens. Variables were compared with univariate and multivariate analysis, and predictive models were created. RESULTS: 18.2% of patients had a negative appendicectomy, 9.6% had mucosal only inflammation, 53% had transmural inflammation and 19.2% had gangrenous appendicitis. A strong correlation was found between degree of inflammation and lymphocytes count and CRP/Albumin ratio, both at univariate and multivariate analysis. A predictive model to identify cases of gangrenous appendicitis was developed. CONCLUSION: Low lymphocyte count and high CRP/Albumin ratio combined into a predictive model may have a role in the selection of patients who deserve appendicectomy instead of non-operative management of acute appendicitis.

Serological fingerprints link antiviral activity of therapeutic antibodies to affinity and concentration.

The effectiveness of therapeutic monoclonal antibodies (mAbs) against variants of the SARS-CoV-2 virus is highly variable. As target recognition of mAbs relies on tight binding affinity, we assessed the affinities of five therapeutic mAbs to the receptor binding domain (RBD) of wild type (A), Delta (B.1.617.2), and Omicron BA.1 SARS-CoV-2 (B.1.1.529.1) spike using microfluidic diffusional sizing (MDS). Four therapeutic mAbs showed strongly reduced affinity to Omicron BA.1 RBD, whereas one (sotrovimab) was less impacted. These affinity reductions correlate with reduced antiviral activities suggesting that affinity could serve as a rapid indicator for activity before time-consuming virus neutralization assays are performed. We also compared the same mAbs to serological fingerprints (affinity and concentration) obtained by MDS of antibodies in sera of 65 convalescent individuals. The affinities of the therapeutic mAbs to wild type and Delta RBD were similar to the serum antibody response, indicating high antiviral activities. For Omicron BA.1 RBD, only sotrovimab retained affinities within the range of the serum antibody response, in agreement with high antiviral activity. These results suggest that serological fingerprints provide a route to evaluating affinity and antiviral activity of mAb drugs and could guide the development of new therapeutics.

Both COVID-19 infection and vaccination induce high-affinity cross-clade responses to SARS-CoV-2 variants.

The B.1.1.529 (omicron) variant has rapidly supplanted most other SARS-CoV-2 variants. Using microfluidics-based antibody affinity profiling (MAAP), we have characterized affinity and IgG concentration in the plasma of 39 individuals with multiple trajectories of SARS-CoV-2 infection and/or vaccination. Antibody affinity was similar against the wild-type, delta, and omicron variants (K A ranges: 122 ± 155, 159 ± 148, 211 ± 307 µM-1, respectively), indicating a surprisingly broad and mature cross-clade immune response. Postinfectious and vaccinated subjects showed different IgG profiles, with IgG3 (p-value = 0.002) against spike being more prominent in the former group. Lastly, we found that the ELISA titers correlated linearly with measured concentrations (R = 0.72) but not with affinity (R = 0.29). These findings suggest that the wild-type and delta spike induce a polyclonal immune response capable of binding the omicron spike with similar affinity. Changes in titers were primarily driven by antibody concentration, suggesting that B-cell expansion, rather than affinity maturation, dominated the response after infection or vaccination.

Enhancement of CRISPR/Cas12a trans-cleavage activity using hairpin DNA reporters.

The RNA programmed non-specific (trans) nuclease activity of CRISPR-Cas Type V and VI systems has opened a new era in the field of nucleic acid-based detection. Here, we report on the enhancement of trans-cleavage activity of Cas12a enzymes using hairpin DNA sequences as FRET-based reporters. We discover faster rate of trans-cleavage activity of Cas12a due to its improved affinity (Km) for hairpin DNA structures, and provide mechanistic insights of our findings through Molecular Dynamics simulations. Using hairpin DNA probes we significantly enhance FRET-based signal transduction compared to the widely used linear single stranded DNA reporters. Our signal transduction enables faster detection of clinically relevant double stranded DNA targets with improved sensitivity and specificity either in the presence or in the absence of an upstream pre-amplification step.

Complications and mortality in a cohort of patients undergoing emergency and elective surgery with perioperative SARS-CoV-2 infection: an Italian multicenter study. Teachings of Phase 1 to be brought in Phase 2 pandemic.

Since the beginning of the pandemic due to the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its related disease, coronavirus disease 2019 (COVID-19), several articles reported negative outcomes in surgery of infected patients. Aim of this study is to report results of patients with COVID-19-positive swab, in the perioperative period after surgery. Data of COVID-19-positive patients undergoing emergent or oncological surgery, were collected in a retrospective, multicenter study, which involved 20 Italian institutions. Collected parameters were age, sex, body mass index, COVID-19-related symptoms, patients' comorbidities, surgical procedure, personal protection equipment (PPE) used in operating rooms, rate of postoperative infection among healthcare staff and complications, within 30-postoperative days. 68 patients, who underwent surgery, resulted COVID-19-positive in the perioperative period. Symptomatic patients were 63 (92.5%). Fever was the main symptom in 36 (52.9%) patients, followed by dyspnoea (26.5%) and cough (13.2%). We recorded 22 (32%) intensive care unit admissions, 23 (33.8%) postoperative pulmonary complications and 15 (22%) acute respiratory distress syndromes. As regards the ten postoperative deaths (14.7%), 6 cases were related to surgical complications. One surgeon, one scrub nurse and two circulating nurses were infected after surgery due to the lack of specific PPE. We reported less surgery-related pulmonary complications and mortality in Sars-CoV-2-infected patients, than in literature. Emergent and oncological surgery should not be postponed, but it is mandatory to use full PPE, and to adopt preoperative screenings and strategies that mitigate the detrimental effect of pulmonary complications, mostly responsible for mortality.