Domain reorientation and rotation of an intracellular assembly regulate conduction in Kir potassium channels.

Potassium channels embedded in cell membranes employ gates to regulate K+ current. While a specific constriction in the permeation pathway has historically been implicated in gating, recent reports suggest that the signature ion selectivity filter located in the outer membrane leaflet may be equally important. Inwardly rectifying K+ channels also control the directionality of flow, using intracellular polyamines to stem ion efflux by a valve-like action. This study presents crystallographic evidence of interdependent gates in the conduction pathway and reveals the mechanism of polyamine block. Reorientation of the intracellular domains, concomitant with activation, instigates polyamine release from intracellular binding sites to block the permeation pathway. Conformational adjustments of the slide helices, achieved by rotation of the cytoplasmic assembly relative to the pore, are directly correlated to the ion configuration in the selectivity filter. Ion redistribution occurs irrespective of the constriction, suggesting a more expansive role of the selectivity filter in gating than previously appreciated.

rs822336 binding to C/EBPß and NFIC modulates induction of PD-L1 expression and predicts anti-PD-1/PD-L1 therapy in advanced NSCLC.

Efficient predictive biomarkers are needed for immune checkpoint inhibitor (ICI)-based immunotherapy in non-small cell lung cancer (NSCLC). Testing the predictive value of single nucleotide polymorphisms (SNPs) in programmed cell death 1 (PD-1) or its ligand 1 (PD-L1) has shown contrasting results. Here, we aim to validate the predictive value of PD-L1 SNPs in advanced NSCLC patients treated with ICIs as well as to define the molecular mechanisms underlying the role of the identified SNP candidate. rs822336 efficiently predicted response to anti-PD-1/PD-L1 immunotherapy in advanced non-oncogene addicted NSCLC patients as compared to rs2282055 and rs4143815. rs822336 mapped to the promoter/enhancer region of PD-L1, differentially affecting the induction of PD-L1 expression in human NSCLC cell lines as well as their susceptibility to HLA class I antigen matched PBMCs incubated with anti-PD-1 monoclonal antibody nivolumab. The induction of PD-L1 expression by rs822336 was mediated by a competitive allele-specificity binding of two identified transcription factors: C/EBPß and NFIC. As a result, silencing of C/EBPß and NFIC differentially regulated the induction of PD-L1 expression in human NSCLC cell lines carrying different rs822336 genotypes. Analysis by binding microarray further validated the competitive allele-specificity binding of C/EBPß and NFIC to PD-L1 promoter/enhancer region based on rs822336 genotype in human NSCLC cell lines. These findings have high clinical relevance since identify rs822336 and induction of PD-L1 expression as novel biomarkers for predicting anti-PD-1/PD-L1-based immunotherapy in advanced NSCLC patients.

Enhancing PET Degrading Enzymes: A Combinatory Approach.

Plastic waste has become a substantial environmental issue. A potential strategy to mitigate this problem is to use enzymatic hydrolysis of plastics to depolymerize post-consumer waste and allow it to be reused. Over the last few decades, the use of enzymatic PET-degrading enzymes has shown promise as a great solution for creating a circular plastic waste economy. PsPETase from Piscinibacter sakaiensis has been identified as an enzyme with tremendous potential for such applications. But to improve its efficiency, enzyme engineering has been applied aiming at enhancing its thermal stability, enzymatic activity, and ease of production. Here, we combine different strategies such as structure-based rational design, ancestral sequence reconstruction and machine learning to engineer a more highly active Combi-PETase variant with a melting temperature of 70 °C and optimal performance at 60 °C. Furthermore, this study demonstrates that these approaches, commonly used in other works of enzyme engineering, are most effective when utilized in combination, enabling the improvement of enzymes for industrial applications.

Combined fine needle aspiration cytology and core needle biopsy in the same setting: A two-years' experience.

INTRODUCTION: Fine needle aspiration cytology (FNAC) combined with rapid on-site evaluation (ROSE) and ancillary techniques is an accurate diagnostic tool for many pathologies. However, in some cases, it may not be sufficient for actionable diagnoses or molecular testing, especially for cases that require large immunohistochemical panels or cases in which histological features are mandatory for the diagnosis. Core needle biopsy (CNB), on the contrary, provides samples that are suitable for histological features and sufficient for all ancillary studies. However, CNB is often performed by radiologists or clinicians without the direct participation of cytopathologists, which can lead to missed or delayed diagnoses. This study reports on the experience of combining FNAC and CNB performed in one setting by cytopathologists. The aim was to evaluate the impact of CNB on FNAC and the diagnostic efficiency of the combined procedures. MATERIALS AND METHODS: One hundred forty-two FNAC and CNB procedures performed in the same setting over a period of 2 years were analysed. The FNAC diagnoses were compared and integrated with the subsequent CNB diagnoses. The impact of CNB was categorized as follows: non-contributory, in cases of inadequate samples; confirmed, when the CNB and FNAC diagnoses were the same; improved, when the CNB diagnosis was consistent with the FNAC diagnosis and further specified the corresponding entity; allowed, when CNB produced a diagnosis that could not be reached by FNAC; changed, when the CNB changed the previous FNAC diagnosis. RESULTS: CNB confirmed the FNAC diagnosis in 40.1% of cases (n = 57/142). CNB improved the FNAC diagnosis in 47.2% of cases (n = 67/142). CNB allowed a diagnosis that could not be performed on FNAC in 2.1% of cases (n = 3/142). CNB changed a previous FNAC diagnosis in 2.1% of cases (n = 3/142). CNB was non-contributory in 8.4% of cases (n = 12/142). CNB produced a positive impact on the whole diagnostic procedure in 51.4% of total cases (n = 73/142). The combined FNAC and CNB resulted in actionable diagnoses in 91.5% of all cases (n = 130/142). A complete molecular assessment was successfully performed in 14.7% of cases (n = 21/142) utilizing either FNAC or CNB material. CONCLUSIONS: The combined use of FNAC and CNB in one setting improves the diagnostic accuracy of both procedures. This approach exploits the advantages of each procedure, enhancing the accuracy of the final diagnosis.

Computer-assisted urine cytology: Faster, cheaper, better?

Recent advancements in computer-assisted diagnosis (CAD) have catalysed significant progress in pathology, particularly in the realm of urine cytopathology. This review synthesizes the latest developments and challenges in CAD for diagnosing urothelial carcinomas, addressing the limitations of traditional urinary cytology. Through a literature review, we identify and analyse CAD models and algorithms developed for urine cytopathology, highlighting their methodologies and performance metrics. We discuss the potential of CAD to improve diagnostic accuracy, efficiency and patient outcomes, emphasizing its role in streamlining workflow and reducing errors. Furthermore, CAD tools have shown potential in exploring pathological conditions, uncovering novel biomarkers and prognostic/predictive features previously unknown or unseen. Finally, we examine the practical issues surrounding the integration of CAD into clinical practice, including regulatory approval, validation and training for pathologists. Despite the promising results, challenges remain, necessitating further research and validation efforts. Overall, CAD presents a transformative opportunity to revolutionize diagnostic practices in urine cytopathology, paving the way for enhanced patient care and outcomes.

Resident training in interventional pathology: Ultrasound-guided fine-needle aspiration and rapid on site evaluation-5 years of teaching experience in a single university hospital.

INTRODUCTION: Despite the established role of the interventional pathologist, their diagnostic performance is difficult to establish. At least in Spain training of pathology residents in ultrasound-guided interventional procedures for specimen collection is limited or absent in most institutions. We present our teaching experience in the instruction of ultrasound-guided fine-needle aspiration (FNA) to pathology residents in a tertiary-level hospital. MATERIALS AND METHODS: The training of pathology residents who rotated through the interventional unit of the pathology department and the application of ultrasound-guided FNA and rapid on-site evaluation (U-ROSE) was documented over 5 years. The training period was broken down into learning phases and included the number of ultrasound-guided FNA performed, anatomical location, and their diagnostic performance, among other aspects. RESULTS: Nineteen (19) pathology residents were trained in U-ROSE, and performed a total of 4003 procedures, with a mean of 211 per resident. In 53% of cases only one pass was required for an adequated sample. The specimen was diagnostic in more than 97% of cases. The most frequently sampled anatomical sites were the thyroid gland (n = 2347), followed by lymph node (n = 667), soft tissues (n = 663) and salivary glands (n = 322). CONCLUSION: The results support the training programme followed by pathology residents in learning U-ROSE, which is essential to lay the foundations for the future interventional pathologist.

Advances in radiology and pathology of prostate cancer: a review for the pathologist.

Multiparametric magnetic resonance imaging (mpMRI) has improved systematic prostate biopsy procedures in the diagnosis of clinically significant prostate cancer (csPCa) by reducing the number of unnecessary biopsies; numerous level one evidence studies have confirmed the accuracy of MRI-targeted biopsy, but, still today, systematic prostate biopsy is recommended to reduce the 15-20% false negative rate of mpMRI. New advanced imaging has been proposed to detect suspicious lesions and perform targeted biopsies especially when mpMRI cannot be performed. Transrectal ultrasound (TRUS) modalities are emerging as methods with greater sensitivity and specificity for the detection of PCa compared to the traditional TRUS; these techniques include elastography and contrast-enhanced ultrasound, as well as improved B-mode and Doppler techniques. These modalities can be combined to define a novel ultrasound approach: multiparametric ultrasound (mpUS). More recently, micro-ultrasound (MicroUS) and prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) have demonstrated to be sensitive for the detection of primary prostatic lesions resulting highly correlated with the aggressiveness of the primary prostatic tumor. In parallel, artificial intelligence is advancing and is set out to deeply change both radiology and pathology. In this study we address the role, advantages and shortcomings of novel imaging techniques for Pca, and discuss future directions including the applications of artificial intelligence-based techniques to imaging as well as histology. The significance of these findings for the practicing pathologist is discussed.

Ancestral Sequence Reconstruction Identifies Structural Changes Underlying the Evolution of Ideonella sakaiensis PETase and Variants with Improved Stability and Activity.

The improved production, recycling, and removal of plastic waste, such as polyethylene terephthalate (PET), are pressing environmental and economic issues for society. Biocatalytic (enzymatic) PET depolymerization is potentially a sustainable, low-energy solution to PET recycling, especially when compared with current disposal methods such as landfills, incineration, or gasification. IsPETase has been extensively studied for its use in PET depolymerization; however, its evolution from cutinases is not fully understood, and most engineering studies have neglected the majority of the available sequence space remote from the active site. In this study, ancestral protein reconstruction (ASR) has been used to trace the evolutionary trajectory from ancient serine hydrolases to IsPETase, while ASR and the related design approach, protein repair one-stop shop, were used to identify enzyme variants with improved activity and stability. Kinetic and structural characterization of these variants reveals new insights into the evolution of PETase activity and the role of second-shell mutations around the active site. Among the designed and reconstructed variants, we identified several with melting points 20 °C higher than that of IsPETase and two variants with significantly higher catalytic activity.

Changes in mucosal IgG4+- and IL-10+-cell frequencies in adults with eosinophilic esophagitis on a two-food elimination diet.

Eosinophilic esophagitis (EoE) is increasingly diagnosed in patients with dysphagia. Type-2 immunity can induce EoE histopathology via non-IgE-dependent mechanisms, possibly involving IgG4 and IL-10. To elucidate the contribution of this response to EoE pathogenesis, we examined its association with clinical and histologic endpoints in adult EoE patients given a two-food elimination diet. IgG4- and IL-10-expressing cells were counted in esophageal biopsies and serum food-specific IgG4 measured at baseline and follow-up. Variables were correlated with histologic measures of disease activity. Patients exhibited significant reduction in esophageal eosinophilia and overall histology. A significant decrease in IL-10+-cell frequencies correlated with histologic changes. In contrast, a decline in serum and esophageal IgG4, while substantial, did not correlate with IL-10+-cell frequencies or histologic parameters. These results suggest a critical role of IL-10 in EoE pathogenesis. Conversely, IgG4 expression, while reflecting exposure to food antigens, is not obviously related to EoE histopathology or IL-10 expression.

Application of Digital Imaging and Artificial Intelligence to Pathology of the Placenta.

Digital imaging, including the use of artificial intelligence, has been increasingly applied to investigate the placenta and its related pathology. However, there has been no comprehensive review of this body of work to date. The aim of this study was to therefore review the literature regarding digital pathology of the placenta. A systematic literature search was conducted in several electronic databases. Studies involving the application of digital imaging and artificial intelligence techniques to human placental samples were retrieved and analyzed. Relevant articles were categorized by digital image technique and their relevance to studying normal and diseased placenta. Of 2008 retrieved articles, 279 were included. Digital imaging research related to the placenta was often coupled with immunohistochemistry, confocal microscopy, 3D reconstruction, and/or deep learning algorithms. By significantly increasing pathologists' ability to recognize potentially prognostic relevant features and by lessening inter-observer variability, published data overall indicate that the application of digital pathology to placental and perinatal diseases, along with clinical and radiology correlation, has great potential to improve fetal and maternal health care including the selection of targeted therapy in high-risk pregnancy.

COVID-19 post-vaccination lymphadenopathy: A review of the use of fine needle aspiration cytology.

COVID-19 vaccine-associated clinical lymphadenopathy (C19-LAP) and subclinical lymphadenopathy (SLDI), which are mainly detected by 18F-FDG PET-CT, have been observed after the introduction of RNA-based vaccines during the pandemic. Lymph node (LN) fine needle aspiration cytology (FNAC) has been used to diagnose single cases or small series of SLDI and C19-LAP. In this review, clinical and LN-FNAC features of SLDI and C19-LAP are reported and compared to non-Covid (NC)-LAP. A search for studies on C19-LAP and SLDI histopathology and cytopathology was performed on PubMed and Google Scholar, on 11 January 2023. Reports on LN-FNAC of C19-LAP were retrieved. A total of 14 reports, plus one unpublished case of C19-LAP observed in our institution, diagnosed by LN-FNAC were included in a pooled analysis and compared to the corresponding histopathological reports. In total, 26 cases were included in this review, with a mean age of 50.5 years. Twenty-one lymphadenopathies assessed by LN-FNAC were diagnosed as benign, and three cases as atypical lymphoid hyperplasia; the latter were subsequently confirmed as benign (one by repetition of LN-FNAC, two by histological control). One case of mediastinal lymphadenopathy in a patient suffering from melanoma was reported as reactive granulomatous inflammation, while one unsuspected case was diagnosed as metastasis from melanoma. In all cases, the cytological diagnoses were confirmed by follow-up or excisional biopsy. The high diagnostic value of LN-FNAC in excluding malignant processes was extremely useful in this context and may be particularly valuable when CNB or histological excisions are difficult to perform, as was the case during Covid lockdowns.

The slow-paced digital evolution of pathology: lights and shadows from a multifaceted board.

Objective: The digital revolution in pathology represents an invaluable resource fto optimise costs, reduce the risk of error and improve patient care, even though it is still adopted in a minority of laboratories. Barriers include concerns about initial costs, lack of confidence in using whole slide images for primary diagnosis, and lack of guidance on transition. To address these challenges and develop a programme to facilitate the introduction of digital pathology (DP) in Italian pathology departments, a panel discussion was set up to identify the key points to be considered. Methods: On 21 July 2022, an initial conference call was held on Zoom to identify the main issues to be discussed during the face-to-face meeting. The final summit was divided into four different sessions: (I) the definition of DP, (II) practical applications of DP, (III) the use of AI in DP, (IV) DP and education. Results: Essential requirements for the implementation of DP are a fully tracked and automated workflow, selection of the appropriate scanner based on the specific needs of each department, and a strong commitment combined with coordinated teamwork (pathologists, technicians, biologists, IT service and industries). This could reduce human error, leading to the application of AI tools for diagnosis, prognosis and prediction. Open challenges are the lack of specific regulations for virtual slide storage and the optimal storage solution for large volumes of slides. Conclusion: Teamwork is key to DP transition, including close collaboration with industry. This will ease the transition and help bridge the gap that currently exists between many labs and full digitisation. The ultimate goal is to improve patient care.

Real-world experience with the Sydney System on 1458 cases of lymph node fine needle aspiration cytology.

INTRODUCTION: Lymph node (LN) fine needle aspiration cytology (FNAC) is a safe, quick, inexpensive, reliable, and minimally invasive technique for the diagnosis of lymphadenopathies. Recently, an international committee of experts proposed guidelines for the performance, classification, and reporting of LN-FNAC: the Sydney System. We set out to analyse the diagnostic performance of the Sydney System in a retrospective study. METHODS: We retrieved 1458 LN-FNACs, reformulated the diagnoses according to the Sydney System, and compared them to the histological control where available (n = 551, 37.8%). RESULTS: The risk of malignancy for each of the five categories was 66.7% for inadequate/insufficient, 9.38% for benign (overall: 0.84%), 28.6% for atypical, 100% for suspicious and 99.8% for malignant. LN-FNAC showed a sensitivity of 97.94%, a specificity of 96.92%, a positive predictive value of 99.58%, and a negative predictive value of 86.30%. CONCLUSIONS: These data support the usage of LN-FNAC as an agile first-level technique in the diagnosis of lymphadenopathies. The Sydney System supports and enhances this role of LN-FNAC, and its adoption is encouraged. In negative cases, coupled with ancillary techniques, LN-FNAC can reassure the clinician regarding the benignity of a lymphadenopathy and indicate the need for clinical follow-up, which will catch possible false negatives. In positive cases, LN-FNAC can provide sufficient information, including predictive biomarkers, to initiate management and obviate the need for subsequent, more invasive procedures. Given its speed, minimal invasiveness, and low cost, LN-FNAC can be performed in most cases, even when more invasive techniques are not feasible.

Hematuria in breast cancer: don't forget bladder metastases!

The bladder is a rare site for breast cancer metastases, and only occasional reports are present in the literature. Most cases coexist with synchronous metastases elsewhere, but isolated cases of a single metastatic localization in the urinary bladder have been reported. The most common symptoms of a metastatic localization of breast cancer to the urinary bladder are hematuria and voiding dysfunction. Herein we present three cases of urinary bladder metastasis from breast carcinoma, all presenting with gross hematuria as the only symptom. After a review of the relevant literature, we discuss the clinical and histological characteristics unique to our cases, highlighting potential clinical and pathological diagnostic pitfalls and differential diagnoses.

A Rare Case of Castleman Disease Presenting as an Ovarian Tumor.

Castleman disease (CD) is a rare lymphoproliferative disorder of unknown etiology. Its most common location is the mediastinum, but many other sites have been reported. We report a case of primary CD of the ovary, a rare localization with only 2 cases including the present case described in the world literature to date. A 58-yr-old woman who initially presented with abdominal pain underwent computed tomography scan which showed bilateral well-circumscribed solid adnexal masses. Because an ovarian bilateral tumor was suspected the patient was treated with a hysterectomy and bilateral salpingo-oophorectomy and the histopathologic examination confirmed the diagnosis of CD hyaline-vascular type of the right ovary associated with a contralateral fibroma. Three years after surgery the patient is alive and well and shows no signs of recurrent disease. The occurrence of this rare presentation of CD is the subject of this report. The problems of differential diagnosis with the most frequent lesions of the female pelvis are also discussed.

Nervous Nipple: Pseudopolythelia Caused by a Neurofibroma of the Areola.

ABSTRACT: The presence of a supernumerary nipple inside the original areola is a rare condition termed intra-areolar polythelia. Rarely, a lesion can macroscopically resemble a nipple. We report a case of a solitary neurofibroma (by itself rare in the areola) mimicking a second, twin nipple. In this case, these 2 rare conditions merge resulting in pseudopolythelia. The relevant literature on polythelia and neurofibromas of the breast is briefly reviewed.

Atypical cytological presentation of granular cell tumour: Tumour-associated fibrosis may affect fine-needle aspiration cytology accuracy.

The cytological features of granular cell tumour (GCT) are generally quite typical but, in some cases, the fine needle aspiration cytology (FNAC) diagnosis of GCT may be difficult or impossible because of unusual sites of onset or equivocal cytological features. In this report, two GCTs with atypical FNAC features are described in order to investigate the causes and provide possible diagnostic tips. From a series of nine histologically proven GCTs, two inconclusive FNAC cases were retrieved. Smears were poorly cellular showing isolated naked nuclei, anisonucleosis, granular chromatin and occasional small nucleoli. The background was finely granular in one case. Histological controls of these cases revealed marked fibrosis. Tumour-associated fibrosis in GCT is variable and does not seem to influence clinical behaviour but it influences the harvest and the integrity of granular cells collected by FNAC. When GCT smears are poorly cellular, attention should be paid to the granular background and to the few granular cells, if any, as they might be the only features to suggest a GCT.

Testing EGFR with Idylla on Cytological Specimens of Lung Cancer: A Review.

The current standard of care for advanced non-small-cell lung cancer is based on detecting actionable mutations that can benefit from targeted therapy. Comprehensive genetic tests can have long turn-around times, and because EGFR mutations are the most prevalent actionable mutation, a quick detection would enable a prompt initiation of targeted therapy. Furthermore, the scarcity of diagnostic material means that sometimes only cytologic material is available. The Idylla™ EGFR assay is a real-time PCR-based method able to detect 51 EGFR mutations in 2.5 h. Idylla is validated for use only on FFPE sections, but some researchers described their experiences with cytological material. We reviewed the relevant literature, finding four articles describing 471 cases and many types of cytological input material: smears, cell-block sections, suspensions, and extracted DNA. The sensitivity, specificity, and limit of detection appear comparable to those obtained with histological input material, with one exception: the usage of scraped stained smears as input may reduce the accuracy of the test. In conclusion, usage of cytological material as input to the Idylla EGFR test is possible. A workflow where common mutations are tested first and fast, leaving rarer mutations for subsequent comprehensive profiling, seems the most effective approach.

Histopathology of IBD Colitis. A practical approach from the pathologists of the Italian Group for the study of the gastrointestinal tract (GIPAD).

Inflammatory bowel diseases (IBDs) are lifelong disorders in which an interaction between genetic and environmental factors is involved. IBDs include two entities: Crohn's disease (CD) and ulcerative colitis (UC); these can be adequately diagnosed and distinguished with a correct methodological approach based on communicating exhaustive clinical, endoscopic and laboratory information to the pathologist and performing adequate bioptic sampling and precise morphological signs including crypt architecture, distribution of inflammation and granulomas, when present. IBD needs to be distinguished from non-IBD colitis, mostly at its onset. Moreover, IBDs are associated with an increased risk of developing colorectal adenocarcinoma. In daily pathological practice, correct diagnosis of IBD and its subclassification as well as a correct detection of dysplasia is imperative to establish the best therapeutic approach.

Histopathology of Non-IBD Colitis. A practical approach from the Italian Group for the study of the gastrointestinal tract (GIPAD).

Non-IBD colitides (NIBDC) are intestinal diseases clinically and endoscopically overlapping with Inflammatory Bowel Diseases (IBD), sometimes with a similar histological picture. NIBDC include entities such as infectious colitis, ischemic colitis, pseudomembranous colitis, eosinophilic colitis, autoimmune enterocolitis, segmental colitis associated with diverticulosis, drug-induced colitis, radiation-induced colitis, diversion colitis, and microscopic colitis, this last including two entities: collagenous and lymphocytic colitis. The knowledge of the most useful histological features and the main clinical data for each entity is mandatory in daily clinical practice, for correct pathological diagnosis and clinical management.