Influence of the COVID-19 Pandemic on Patients with Rectal Cancer.

Objectives: The COVID-19 pandemic and its associated restrictions have resulted in delayed diagnoses across various tumor entities, including rectal cancer. Our hypothesis was based on the expectation of a reduced number of primary operations due to higher tumor stages compared to the control group. Methods: In a single-center retrospective study conducted from 1 March 2018 to 1 March 2022, we analyzed 120 patients with an initial diagnosis of rectal cancer. Among them, 65 patients were part of the control group (pre-COVID-19), while 55 patients were included in the study group (during the COVID-19 pandemic). We compared tumor stages, treatment methods, and complications, presenting data as absolute numbers or mean values. Results: Fewer primary tumor resections during the COVID-19 pandemic (p = 0.010), as well as a significantly lower overall number of tumor resections (p = 0.025) were seen compared to the control group. Twenty percent of patients in the COVID-19 group received their diagnosis during lockdown periods. These patients presented significantly higher tumor stages (T4b: 27.3% vs. 6.2%, p = 0.025) compared to the control group prior to the pandemic. In addition, more patients with angiolymphatic invasion (ALI) were identified in the COVID-19 group following neoadjuvant treatment compared to the control group (p = 0.027). No differences were noted between the groups regarding complications, stoma placement, or conversion rates. Conclusions: The COVID-19 pandemic, particularly during lockdown, appears to have contributed to delayed diagnoses, resulting in higher tumor stages and a decreased number of surgeries. The quality of rectal cancer treatment can be maintained under pandemic conditions.

FDG-PET/CT is a powerful tool to predict and evaluate response to chimeric antigen receptor (CAR) T-cell therapy in Non-Hodgkin-Lymphoma (NHL).

Chimeric antigen receptor (CAR) T-cell therapy has dramatically shifted the landscape of treatment especially for Non-Hodgkin-Lymphoma (NHL). This study evaluates the role of fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in NHL treated with CAR T-cell therapy concerning response assessment and prognosis.We evaluated 34 patients with NHL who received a CAR T-cell therapy between August 2019 and July 2022. All patients underwent a pre-therapeutic FDG-PET/CT (PET-0) 6 days prior and a post-therapeutic FDG-PET/CT (PET-1) 34 days after CAR T-cell therapy. Deauville score (DS) was used for evaluation of response to therapy and compared to a minimum follow-up of 5 months.19/34 (55.9%) patients achieved DS ≤ 3 on PET-1, the remaining 15 (44.1%) patients had DS > 3 on PET-1. 14/19 patients with DS ≤ 3 on PET-1 had no relapsed or refractory (r/r)-disease and were still alive at last follow-up. The other 5 patients had r/r-disease and 4 of these died. Except for two patients who had no r/r-disease, all other patients (13/15) with DS > 3 on PET-1 had r/r-disease and 12 of these subsequently died. Patients with DS ≤ 3 on PET-1 had significantly better progression free survival (PFS; HR: 5.7; p < 0.01) and overall survival (OS; HR: 5.0; p < 0.01) compared to patients with DS > 3 on PET-1. In addition, we demonstrated that patients with DS ≤ 4 on PET-0 tended to have longer PFS (HR: 3.6; p = 0.05).Early FDG-PET/CT using the established DS after CAR T-cell therapy is a powerful tool to evaluate response to therapy.

Virtual reality-empowered deep-learning analysis of brain cells.

Automated detection of specific cells in three-dimensional datasets such as whole-brain light-sheet image stacks is challenging. Here, we present DELiVR, a virtual reality-trained deep-learning pipeline for detecting c-Fos+ cells as markers for neuronal activity in cleared mouse brains. Virtual reality annotation substantially accelerated training data generation, enabling DELiVR to outperform state-of-the-art cell-segmenting approaches. Our pipeline is available in a user-friendly Docker container that runs with a standalone Fiji plugin. DELiVR features a comprehensive toolkit for data visualization and can be customized to other cell types of interest, as we did here for microglia somata, using Fiji for dataset-specific training. We applied DELiVR to investigate cancer-related brain activity, unveiling an activation pattern that distinguishes weight-stable cancer from cancers associated with weight loss. Overall, DELiVR is a robust deep-learning tool that does not require advanced coding skills to analyze whole-brain imaging data in health and disease.

Robotic-Assisted versus Laparoscopic Surgery for Rectal Cancer: An Analysis of Clinical and Financial Outcomes from a Tertiary Referral Center.

Background: The popularity of robotic-assisted surgery for rectal cancer is increasing, but its superiority over the laparoscopic approach regarding safety, efficacy, and costs has not been well established. Methods: A retrospective single-center study was conducted comparing consecutively performed robotic-assisted and laparoscopic surgeries for rectal cancer between 1 January 2016 and 31 September 2021. In total, 125 adult patients with sporadic rectal adenocarcinoma (distal extent ≤ 15 cm from the anal verge) underwent surgery where 66 were operated on robotically and 59 laparoscopically. Results: Severe postoperative complications occurred less frequently with robotic-assisted compared with laparoscopic surgery, as indicated by Clavien-Dindo classification grades 3b-5 (13.6% vs. 30.5%, p = 0.029). Multiple logistic regression analyses after backward selection revealed that robotic-assisted surgery was associated with a lower rate of total (Clavien-Dindo grades 1-5) (OR = 0.355; 95% CI 0.156-0.808; p = 0.014) and severe postoperative complications (Clavien-Dindo grades 3b-5) (OR = 0.243; 95% CI 0.088-0.643; p = 0.005). Total inpatient costs (median EUR 17.663 [IQR EUR 10.151] vs. median EUR 14.089 [IQR EUR 12.629]; p = 0.018) and surgery costs (median EUR 10.156 [IQR EUR 3.551] vs. median EUR 7.468 [IQR EUR 4.074]; p < 0.0001) were higher for robotic-assisted surgery, resulting in reduced total inpatient profits (median EUR -3.196 [IQR EUR 9.101] vs. median EUR 232 [IQR EUR 6.304]; p = 0.004). Conclusions: In our study, robotic-assisted surgery for rectal cancer resulted in less severe and fewer total postoperative complications. Still, it was associated with higher surgery and inpatient costs. With increasing experience, the operative time may be reduced, and the postoperative recovery may be further accelerated, leading to reduced surgery and total inpatient costs.

Impact of Coronavirus Disease 2019 (COVID-19) Pandemic on Surgical Site Infection in Patients with Inflammatory Bowel Disease-A Monocentric, Retrospective Cohort Study.

(1) Background: Surgical site infections (SSIs) are a relevant problem with a 25% incidence rate after elective laparotomy due to inflammatory bowel disease (IBD). The aim of this study was to evaluate whether stricter hygienic measures during the COVID-19 pandemic influenced the rate of SSI. (2) Methods: This is a monocentric, retrospective cohort study comparing the rate of SSI in patients with bowel resection due to IBD during COVID-19 (1 March 2020-15 December 2021) to a cohort pre-COVID-19 (1 February 2015-25 May 2018). (3) Results: The rate of SSI in IBD patients with bowel resection was 25.8% during the COVID-19 pandemic compared to 31.8% pre-COVID-19 (OR 0.94; 95% CI 0.40-2.20; p = 0.881). There were seventeen (17.5%) superficial and four (4.1%) deep incisional and organ/space SSIs, respectively, during the COVID-19 pandemic (p = 0.216). There were more postoperative intra-abdominal abscesses during COVID-19 (7.2% vs. 0.9%; p = 0.021). The strictness of hygienic measures (mild, medium, strict) had no influence on the rate of SSI (p = 0.553). (4) Conclusions: Hygienic regulations in hospitals during COVID-19 did not significantly reduce the rate of SSI in patients with bowel resection due to IBD. A ban on surgery, whereby only emergency surgery was allowed, was likely to delay surgery and exacerbate the disease, which probably contributed to more SSIs and postoperative complications.

Patient and dermatologists' perspectives on augmented intelligence for melanoma screening: A prospective study.

BACKGROUND: Artificial intelligence (AI) shows promising potential to enhance human decision-making as synergistic augmented intelligence (AuI), but requires critical evaluation for skin cancer screening in a real-world setting. OBJECTIVES: To investigate the perspectives of patients and dermatologists after skin cancer screening by human, artificial and augmented intelligence. METHODS: A prospective comparative cohort study conducted at the University Hospital Basel included 205 patients (at high-risk of developing melanoma, with resected or advanced disease) and 8 dermatologists. Patients underwent skin cancer screening by a dermatologist with subsequent 2D and 3D total-body photography (TBP). Any suspicious and all melanocytic skin lesions ≥3 mm were imaged with digital dermoscopes and classified by corresponding convolutional neural networks (CNNs). Excisions were performed based on dermatologist's melanoma suspicion, study-defined elevated CNN risk-scores and/or melanoma suspicion by AuI. Subsequently, all patients and dermatologists were surveyed about their experience using questionnaires, including quantification of patient's safety sense following different examinations (subjective safety score (SSS): 0-10). RESULTS: Most patients believed AI could improve diagnostic performance (95.5%, n = 192/201). In total, 83.4% preferred AuI-based skin cancer screening compared to examination by AI or dermatologist alone (3D-TBP: 61.3%; 2D-TBP: 22.1%, n = 199). Regarding SSS, AuI induced a significantly higher feeling of safety than AI (mean-SSS (mSSS): 9.5 vs. 7.7, p < 0.0001) or dermatologist screening alone (mSSS: 9.5 vs. 9.1, p = 0.001). Most dermatologists expressed high trust in AI examination results (3D-TBP: 90.2%; 2D-TBP: 96.1%, n = 205). In 68.3% of the examinations, dermatologists felt that diagnostic accuracy improved through additional AI-assessment (n = 140/205). Especially beginners (<2 years' dermoscopic experience; 61.8%, n = 94/152) felt AI facilitated their clinical work compared to experts (>5 years' dermoscopic experience; 20.9%, n = 9/43). Contrarily, in divergent risk assessments, only 1.5% of dermatologists trusted a benign CNN-classification more than personal malignancy suspicion (n = 3/205). CONCLUSIONS: While patients already prefer AuI with 3D-TBP for melanoma recognition, dermatologists continue to rely largely on their own decision-making despite high confidence in AI-results. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04605822).

Role of visceral fat on postoperative complications and relapse in patients with Crohn's disease after ileocecal resection: Is it overrated?

INTRODUCTION: The role of visceral fat in disease development, particularly in Crohn´s disease (CD), is significant. However, its preoperative prognostic value for postoperative complications and CD relapse after ileocecal resection (ICR) remains unknown. This study aims to assess the predictive potential of preoperatively measured visceral and subcutaneous fat in postoperative complications and CD recurrence using magnetic resonance imaging (MRI). The primary endpoint was postoperative anastomotic leakage of the ileocolonic anastomosis, with secondary endpoints evaluating postoperative complications according to the Clavien Dindo classification and CD recurrence at the anastomosis. METHODS: We conducted a retrospective analysis of 347 CD patients who underwent ICR at our tertiary referral center between 2010 and 2020. We included 223 patients with high-quality preoperative MRI scans, recording demographics, postoperative outcomes, and CD recurrence rates at the anastomosis. To assess adipose tissue distribution, we measured total fat area (TFA), visceral fat area (VFA), subcutaneous fat area (SFA), and abdominal circumference (AC) at the lumbar 3 (L3) level using MRI cross-sectional images. Ratios of these values were calculated. RESULTS: None of the radiological variables showed an association with anastomotic leakage (TFA p = 0.932, VFA p = 0.982, SFA p = 0.951, SFA/TFA p = 0.422, VFA/TFA p = 0.422), postoperative complications, or CD recurrence (TFA p = 0.264, VFA p = 0.916, SFA p = 0.103, SFA/TFA p = 0.059, VFA/TFA p = 0.059). CONCLUSIONS: Radiological visceral obesity variables were associated with postoperative outcomes or clinical recurrence in CD patients undergoing ICR. Preoperative measurement of visceral fat measurement is not specific for predicting postoperative complications or CD relapse.

Analysis of acute COVID-19 including chronic morbidity: protocol for the deep phenotyping National Pandemic Cohort Network in Germany (NAPKON-HAP).

BACKGROUND: The severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) pandemic causes a high burden of acute and long-term morbidity and mortality worldwide despite global efforts in containment, prophylaxis, and therapy. With unprecedented speed, the global scientific community has generated pivotal insights into the pathogen and the host response evoked by the infection. However, deeper characterization of the pathophysiology and pathology remains a high priority to reduce morbidity and mortality of coronavirus disease 2019 (COVID-19). METHODS: NAPKON-HAP is a multi-centered prospective observational study with a long-term follow-up phase of up to 36 months post-SARS-CoV-2 infection. It constitutes a central platform for harmonized data and biospecimen for interdisciplinary characterization of acute SARS-CoV-2 infection and long-term outcomes of diverging disease severities of hospitalized patients. RESULTS: Primary outcome measures include clinical scores and quality of life assessment captured during hospitalization and at outpatient follow-up visits to assess acute and chronic morbidity. Secondary measures include results of biomolecular and immunological investigations and assessment of organ-specific involvement during and post-COVID-19 infection. NAPKON-HAP constitutes a national platform to provide accessibility and usability of the comprehensive data and biospecimen collection to global research. CONCLUSION: NAPKON-HAP establishes a platform with standardized high-resolution data and biospecimen collection of hospitalized COVID-19 patients of different disease severities in Germany. With this study, we will add significant scientific insights and provide high-quality data to aid researchers to investigate COVID-19 pathophysiology, pathology, and chronic morbidity.

How to exclude pulmonary embolism in patients hospitalized with COVID-19: a comparison of predictive scores.

BACKGROUND: Pulmonary embolism (PE) is an important complication of Coronavirus disease 2019 (COVID-19). COVID-19 is associated with respiratory impairment and a pro-coagulative state, rendering PE more likely and difficult to recognize. Several decision algorithms relying on clinical features and D-dimer have been established. High prevalence of PE and elevated Ddimer in patients with COVID-19 might impair the performance of common decision algorithms. Here, we aimed to validate and compare five common decision algorithms implementing age adjusted Ddimer, the GENEVA, and Wells scores as well as the PEGeD- and YEARS-algorithms in patients hospitalized with COVID-19. METHODS: In this single center study, we included patients who were admitted to our tertiary care hospital in the COVID-19 Registry of the LMU Munich. We retrospectively selected patients who received a computed tomography pulmonary angiogram (CTPA) or pulmonary ventilation/perfusion scintigraphy (V/Q) for suspected PE. The performances of five commonly used diagnostic algorithms (age-adjusted D-dimer, GENEVA score, PEGeD-algorithm, Wells score, and YEARS-algorithm) were compared. RESULTS: We identified 413 patients with suspected PE who received a CTPA or V/Q confirming 62 PEs (15%). Among them, 358 patients with 48 PEs (13%) could be evaluated for performance of all algorithms. Patients with PE were older and their overall outcome was worse compared to patients without PE. Of the above five diagnostic algorithms, the PEGeD- and YEARS-algorithms performed best, reducing diagnostic imaging by 14% and 15% respectively with a sensitivity of 95.7% and 95.6%. The GENEVA score was able to reduce CTPA or V/Q by 32.2% but suffered from a low sensitivity (78.6%). Age-adjusted D-dimer and Wells score could not significantly reduce diagnostic imaging. CONCLUSION: The PEGeD- and YEARS-algorithms outperformed other tested decision algorithms and worked well in patients admitted with COVID-19. These findings need independent validation in a prospective study.

Immune Phenotypic Characterization of a TRAIL-Knockout Mouse.

The TNF-superfamily member TRAIL is known to mediate selective apoptosis in tumor cells suggesting this protein as a potential antitumor drug target. However, initial successful pr-clinical results could not be translated into the clinic. Reasons for the ineffectiveness of TRAIL-targeting in tumor therapies could include acquired TRAIL resistance. A tumor cell acquires TRAIL resistance, for example, by upregulation of antiapoptotic proteins. In addition, TRAIL can also influence the immune system and thus, tumor growth. We were able to show in our previous work that TRAIL-/- mice show improved survival in a mouse model of pancreatic carcinoma. Therefore, in this study we aimed to immunologically characterize the TRAIL-/- mice. We observed no significant differences in the distribution of CD3+, CD4+, CD8+ T-cells, Tregs, and central memory CD4+ and CD8+ cells. However, we provide evidence for relevant differences in the distribution of effector memory T-cells and CD8+CD122+ cells but also in dendritic cells. Our findings suggest that T-lymphocytes of TRAIL-/- mice proliferate at a lower rate, and that the administration of recombinant TRAIL significantly increases their proliferation, while regulatory T-cells (Tregs) from TRAIL-/- mice are less suppressive. Regarding the dendritic cells, we found more type-2 conventional dendritic cells (DC2s) in the TRAIL-/- mice. For the first time (to the best of our knowledge), we provide a comprehensive characterization of the immunological landscape of TRAIL-deficient mice. This will establish an experimental basis for future investigations of TRAIL-mediated immunology.

Spatial proteomics in three-dimensional intact specimens.

Spatial molecular profiling of complex tissues is essential to investigate cellular function in physiological and pathological states. However, methods for molecular analysis of large biological specimens imaged in 3D are lacking. Here, we present DISCO-MS, a technology that combines whole-organ/whole-organism clearing and imaging, deep-learning-based image analysis, robotic tissue extraction, and ultra-high-sensitivity mass spectrometry. DISCO-MS yielded proteome data indistinguishable from uncleared samples in both rodent and human tissues. We used DISCO-MS to investigate microglia activation along axonal tracts after brain injury and characterized early- and late-stage individual amyloid-beta plaques in a mouse model of Alzheimer's disease. DISCO-bot robotic sample extraction enabled us to study the regional heterogeneity of immune cells in intact mouse bodies and aortic plaques in a complete human heart. DISCO-MS enables unbiased proteome analysis of preclinical and clinical tissues after unbiased imaging of entire specimens in 3D, identifying diagnostic and therapeutic opportunities for complex diseases. VIDEO ABSTRACT.

Quantitation of SARS-CoV-2 neutralizing antibodies with a virus-free, authentic test.

Neutralizing antibodies (NAbs), and their concentration in sera of convalescents and vaccinees are a correlate of protection from COVID-19. The antibody concentrations in clinical samples that neutralize SARS-CoV-2 are difficult and very cumbersome to assess with conventional virus neutralization tests (cVNTs), which require work with the infectious virus and biosafety level 3 containment precautions. Alternative virus neutralization tests currently in use are mostly surrogate tests based on direct or competitive enzyme immunoassays or use viral vectors with the spike protein as the single structural component of SARS-CoV-2. To overcome these obstacles, we developed a virus-free, safe and very fast (4.5 h) in vitro diagnostic test based on engineered yet authentic SARS-CoV-2 virus-like-particles (VLPs). They share all features of the original SARS-CoV-2 but lack the viral RNA genome and thus are non-infectious. NAbs induced by infection or vaccination, but also potentially neutralizing monoclonal antibodies can be reliably quantified and assessed with ease and within hours with our test, because they interfere and block the ACE2-mediated uptake of VLPs by recipient cells. Results from the VLP neutralization test (VLPNT) showed excellent specificity and sensitivity and correlated very well with a cVNT using fully infectious SARS-CoV-2. The results also demonstrated the reduced neutralizing capacity of COVID-19 vaccinee sera against variants of concern of SARS-CoV-2 including omicron B.1.1.529, BA.1.

Robotic-Assisted versus Laparoscopic Proctectomy with Ileal Pouch-Anal Anastomosis for Ulcerative Colitis: An Analysis of Clinical and Financial Outcomes from a Tertiary Referral Center.

Background: Robotic-assisted colorectal surgery is gaining popularity, but limited data are available on the safety, efficacy, and cost of robotic-assisted restorative proctectomy with the construction of an ileal pouch and ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC). Methods: A retrospective study was conducted comparing consecutively performed robotic-assisted and laparoscopic proctectomy with IPAA between 1 January 2016 and 31 September 2021. In total, 67 adult patients with medically refractory UC without proven dysplasia or carcinoma underwent surgery: 29 operated robotically and 38 laparoscopically. Results: There were no differences between both groups regarding postoperative complications within 30 days according to Clavien-Dindo classification' grades 1−5 (51.7% vs. 42.1%, p = 0.468) and severe grades 3b−5 (17.2% vs. 10.5%, p = 0.485). Robotic-assisted surgery was associated with an increased urinary tract infection rate (n = 7, 24.1% vs. n = 1, 2.6%; p = 0.010) and longer operative time (346 ± 65 min vs. 281 ± 66 min; p < 0.0001). Surgery costs were higher when operated robotically (median EUR 10.377 [IQR EUR 4.727] vs. median EUR 6.689 [IQR EUR 3.170]; p < 0.0001), resulting in reduced total inpatient profits (median EUR 110 [IQR EUR 4.971] vs. median EUR 2.853 [IQR EUR 5.386]; p = 0.001). Conclusion: Robotic-assisted proctectomy with IPAA can be performed with comparable short-term clinical outcomes to laparoscopy but is associated with a longer duration of surgery and higher surgery costs. As experience increases, some advantages may become evident regarding operative time, postoperative recovery, and length of stay. The robotic procedure might then become cost-efficient.

Accumulation of mutations in antibody and CD8 T cell epitopes in a B cell depleted lymphoma patient with chronic SARS-CoV-2 infection.

Antibodies against the spike protein of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) can drive adaptive evolution in immunocompromised patients with chronic infection. Here we longitudinally analyze SARS-CoV-2 sequences in a B cell-depleted, lymphoma patient with chronic, ultimately fatal infection, and identify three mutations in the spike protein that dampen convalescent plasma-mediated neutralization of SARS-CoV-2. Additionally, four mutations emerge in non-spike regions encoding three CD8 T cell epitopes, including one nucleoprotein epitope affected by two mutations. Recognition of each mutant peptide by CD8 T cells from convalescent donors is reduced compared to its ancestral peptide, with additive effects resulting from double mutations. Querying public SARS-CoV-2 sequences shows that these mutations have independently emerged as homoplasies in circulating lineages. Our data thus suggest that potential impacts of CD8 T cells on SARS-CoV-2 mutations, at least in those with humoral immunodeficiency, warrant further investigation to inform on vaccine design.

Intraoperative Fluoroscopy Allows the Reliable Assessment of Deformity Correction during Periacetabular Osteotomy.

We aimed to determine the accuracy and reliability of measures characterizing anterior, lateral, and posterior acetabular coverage on intraoperative fluoroscopic images compared to postoperative radiographs when performing periacetabular osteotomies (PAOs). A study involving 100 PAOs was initiated applying a standardized intraoperative imaging protocol. Coverage was determined by the lateral center edge angle (LCEA), the Tönnis angle (TA), and the anterior and posterior wall index (AWI, PWI). An intraclass correlation coefficient (ICC) model was used to assess interrater (ICC (3,2)) and intrarater (ICC (2,1)) reliability. The ICC (2,2) between analyses obtained from intraoperative fluoroscopy and postoperative radiographs and the corresponding 95% confidence interval (CI) were determined and complemented by Bland-Altman analysis, the mean difference, and 95% limits of agreement (LOA). The ICCs were 0.849 for the LCEA (95% CI 0.783-0.896), 0.897 for the TA (95% CI 0.851-0.930), 0.864 for the AWI (95% CI 0.804-0.907), and 0.804 for the PWI (0.722-0.864). The assessed interrater reliability was excellent except for the AWI, which was graded good (ICC = 0.857, 95% CI 0.794-0.902). Interrater agreement was generally good and fair for the AWI (ICC = 0.715, 95% CI 0.603-0.780). For each postoperative radiograph, interrater reliability was good with ICCs ranging from 0.813 (TA) to 0.881 (PWI). Intrarater reliability was good for all measurements and excellent for the preoperative TA (ICC = 0.993, 95% CI 0.984-0.997) and PWI (ICC = 0.954, 95% CI 0.919-0.97). In summary, we confirm the validity and reliability of intraoperative fluoroscopy as an alternative imaging modality to radiography to evaluate acetabular fragment orientation during PAO. We affirm the LCEA and TA as precise measures for lateral head coverage, and show the suitability of the AWI and PWI to steadily assess acetabular version.

Quantitation of SARS-CoV-2 neutralizing antibodies with a virus-free, authentic test

Neutralizing antibodies (NAbs), and their concentration in sera of convalescents and vaccinees are a solid correlate of protection from COVID-19. The antibody concentrations in clinical samples that neutralize SARS-CoV-2 are difficult and very cumbersome to assess with conventional virus neutralization tests (cVNTs), which require work with the infectious virus and biosafety level 3 containment precautions. Alternative virus neutralization tests currently in use are mostly surrogate tests based on direct or competitive ELISA formats or use viral vectors with the spike protein as the single structural component of SARS-CoV-2. To overcome these obstacles, we developed a virus-free, safe and very fast (4.5 h) in vitro diagnostic test based on engineered yet authentic SARS-CoV-2 virus-like-particles (VLPs). They share all features of the original SARS-CoV-2 but lack the viral RNA genome and thus are non-infectious. NAbs induced by infection or vaccination, but also potentially neutralizing monoclonal antibodies can be reliably quantified and assessed with ease and within hours with our test, because they interfere and block the ACE2-mediated uptake of VLPs by recipient cells. Results from the VLP neutralization test (VLPNT) show excellent correlation to a cVNT with fully infectious SARS-CoV-2 and allow to estimate the reduced neutralization capacity of COVID-19 vaccinee sera with variants of concern of SARS-CoV-2. Author summaryThe current pandemic caused by SARS-CoV-2 is a major challenge not only for COVID-19 patients, medical staff, healthcare systems and the general public, but also virologists and clinical laboratories. A particular challenge are safety issues which require biological safety level 3 to work with and study the pathogen. An alternative are virus-like particles (VLPs) of SARS-CoV-2, which are authentic in terms of viral structure and function but are harmless bioproducts in nature. We engineered VLPs which are close-to-perfect mimics of SARS-CoV-2 by all structural, biochemical, physical and functional criteria tested. SARS-CoV-2 VLPs were used in virus neutralization tests (VNTs). Because high concentrations of neutralizing antibodies correlate with protection from COVID-19 practical VNTs are urgently needed. We developed an authentic, virus-free, thus safe yet very fast in vitro diagnostic test with SARS-CoV-2 VLPs. Virus neutralizing antibodies induced by natural infection or vaccination but also certain monoclonal antibodies inhibit VLP fusion with recipient cells carrying ACE2. Quantitative results from a conventional neutralization test with fully infectious SARS-CoV-2 and results from the VLP-based neutralization test correlate perfectly. The setup of the test is very flexible and allows to analyze sera for their neutralizing capacity against different variants of concern and in a standardized assay format.

[The importance of radiotherapy in rectal cancer-an update from a surgeon's perspective]. / Der Stellenwert der Strahlentherapie beim Rektumkarzinom ­ ein Update aus Sicht des Chirurgen.

BACKGROUND: Neoadjuvant chemoradiotherapy was implemented in the treatment of rectal cancer for UICC stages II and III in 2004. Recent studies have provided new insights with respect to the indications and sequence of radiotherapy in the concept of multimodal treatment. OBJECTIVE: The aim of the study was to review the status of radiotherapy in the context of current developments in the treatment of rectal cancer, such as magnetic resonance imaging (MRI)-based surgery, total neoadjuvant therapy and the watch and wait strategy for complete clinical remission. RESULTS: The indications for neoadjuvant radiotherapy based on the clinical T and N stages are not exact and can lead to overtreatment in 18-27% of cases. Radiotherapy is associated with a worsening of anorectal and urogenital functions. Local recurrence rates of 3% with surgery alone can be achieved in patients with negative circumferential resection margins (low risk cancer) in MRI. For rectal cancer with high-risk features, such as cT4 tumor, positive circumferential resection margins and extramural vascular invasion, an improved disease-free survival and a lower rate of distant metastases could be achieved with total neoadjuvant therapy compared to standard neoadjuvant chemoradiotherapy in recent phase III randomized trials. Pathological complete remission is achieved in 28% of patients after total neoadjuvant therapy. CONCLUSION: The high rate of complete remission has fired the debate regarding watch and wait after total neoadjuvant therapy; however, no prospective randomized phase III trials comparing total mesorectal resection vs. watch and wait in complete clinical remission have been published. Hence, resection remains the gold standard in this scenario given the excellent long-term oncological results.

[Surgical site infections-Prevention and treatment strategies]. / Postoperative Wundinfektionen ­ Vermeidungs- und Behandlungsstrategien.

Surgical site infections (SSI) are the most frequent nosocomial infection in Germany. They are defined as an infection of the surgical site that occurs within 30 days after a surgical procedure. The diagnostic criteria include localized pain or tenderness, localized swelling, erythema, excess warmth, purulent drainage from the incision and cultural detection of pathogens in an aseptically obtained specimen from the incision. Wound infections are differentiated into superficial incisional (grade 1), deep incisional (grade 2) and infections of organs and body cavities in the region of the operation (grade 3). Risk factors for SSI include anemia, immunosuppression, diabetes mellitus, obesity, smoking and malnutrition. The crucial preoperative preventive measures are antisepsis of the surgical area and antibiotic prophylaxis. Intraoperative subcutaneous wound irrigation with an antiseptic solution reduces SSI in visceral surgery. The primary treatment encompasses the liberal debridement of the wound.

Machine learning analysis of whole mouse brain vasculature.

Tissue clearing methods enable the imaging of biological specimens without sectioning. However, reliable and scalable analysis of large imaging datasets in three dimensions remains a challenge. Here we developed a deep learning-based framework to quantify and analyze brain vasculature, named Vessel Segmentation & Analysis Pipeline (VesSAP). Our pipeline uses a convolutional neural network (CNN) with a transfer learning approach for segmentation and achieves human-level accuracy. By using VesSAP, we analyzed the vascular features of whole C57BL/6J, CD1 and BALB/c mouse brains at the micrometer scale after registering them to the Allen mouse brain atlas. We report evidence of secondary intracranial collateral vascularization in CD1 mice and find reduced vascularization of the brainstem in comparison to the cerebrum. Thus, VesSAP enables unbiased and scalable quantifications of the angioarchitecture of cleared mouse brains and yields biological insights into the vascular function of the brain.