A review of the directly sampled endometrial cytology on LBC samples: Classification, microscopic criteria and beyond

The Yokohama System for Reporting Endometrial Cytology (TYS) has been proposed by an expert meeting under the auspices of the International Academy of Cytology (IAC) in May 2016 at the IAC in Yokohama. Since its introduction, the TYS has been receiving worldwide acceptance, and this review aims to assess its global impact. The adoption of endometrial cytology as a diagnostic procedure has been hampered in the past by difficulties arising in interpreting the cellular findings due to a number of factors (such as excess blood, cellular overlapping and the complex physiology of endometrium). Recently, the use of liquid-based cytology (LBC), with its ability to remove blood and mucus and to distribute cells uniformly in a thin layer on the slide, has provided an opportunity to re-evaluate the role of endometrial cytology. LBC is a useful tool in the cytologic diagnosis and follow-up of endometrial abnormalities, which remains complementary to the emerging molecular diagnostic cytopathology. The study of LBC from endometrial cytology could be challenging since it is affected by numerous look-alikes and diagnostic pitfalls. This review discusses these various entities and takes into consideration the ancillary techniques that may be useful in the diagnostic procedure. In conclusion, our review of the published data suggests that the TYS is a valid classification scheme that has been widely accepted by cytopathologists globally, is highly reproducible and makes a valuable contribution to clinical therapeutic management. At present, molecular cytopathology is a rapidly evolving field of modern cytopathology, which underlines the effective interplay between genomics and cytology. This review aims to provide a comprehensive review of the drawbacks of endometrial cytopathology, particularly in terms of endometrial cancer diagnosis and molecular testing.

Telecytology - remote rapid on-site evaluation for ultrasound-guided head and neck fine needle aspiration utilising a clinical imaging assistant with an extended practice role

OBJECTIVE

Rapid On-Site Evaluation (ROSE) of fine needle aspirations (FNA) is widely accepted as best practice, resulting in better outcomes and delivery of care for patients. However, it is not always practical for cytology laboratories to release staff. To increase the availability of ROSE, this study aimed to robustly test the effectiveness of Telecytology ROSE (TCROSE) utilising a clinical imaging assistant (CIA) to prepare the samples and operate the microscope.

METHODS

The study was divided into 3 phases. Phase 1, equipment testing, validation and in-house training for the CIA and the Consultant Biomedical Scientist (CBMS) performing TCROSE. Phase 2, Verifying TCROSE on the same site as the cytology laboratory and phase 3, TCROSE utilising a clinic at a peripheral site away from the cytology laboratory.

RESULTS

78/80 (97% sensitivity, 95% accuracy) of TCROSE cases matched the final report for assessment of adequacy and sufficient sampling, demonstrating 94% reliability with a 95% confidence value. An appropriately trained CIA effectively prepared the samples and operated the microscope for remote interpretation. The samples were triaged effectively, and biopsy requests were appropriate to reduce the need for repeat procedures and delays in treatment. This approach received positive feedback from patients.

CONCLUSION

TCROSE utilising a CIA provides a highly effective alternative to conventional ROSE, minimising the resources required from cytopathology services and improving patient care and access to best practice. This study supports the validity of trained CIAs for a more involved role in the ultrasound-guided FNA service.

Impression cytology of ocular surface in xeroderma pigmentosum

PURPOSE

To describe cellular alterations detected by impression cytology of the ocular surface in patients with xeroderma pigmentosum. The secondary objective was to assess the reliability of impression cytology in diagnosing ocular surface squamous neoplasia.

METHODS

Patients with xeroderma pigmentosum underwent a single-day complete ophthalmological examination and impression cytology for ocular surface evaluation using 13 mm diameter mixed cellulose esters membrane filters and combined staining with Periodic Acid Schiff, Hematoxylin and Eosin, and Papanicolaou stains followed by microscopic analysis. The cytological findings were correlated with the clinical diagnosis. The impression cytology findings at baseline and one-year follow-up were correlated with the clinical course (no tumor, treated tumor, residual tumor recurrent tumor, new tumor).

RESULTS

Of the 42 patients examined, impression cytology was performed in 62 eyes of 34 participants (65% females). The mean age of patients was 29.6 ± 17 years (range 7-62). Fifteen eyes had a clinical diagnosis of ocular surface squamous neoplasia. Impression cytology showed goblet cells (47, 75%), inflammatory cells (12, 19%), keratinization (5, 8%), and squamous metaplasia (30, 48%). Impression cytology was positive for atypical cells in 18 patients (12 with and 6 without ocular surface squamous neoplasia). The sensitivity, specificity, positive predictive value, and negative predictive value of impression cytology (at baseline) for diagnosis of ocular surface squamous neoplasia were 80%, 87%, 67%, and 93%, respectively, using clinical diagnosis of ocular surface squamous neoplasia as the reference standard.

CONCLUSION

Impression cytology has a moderate positive predictive value for the diagnosis of ocular surface squamous neoplasia in patients with xeroderma pigmentosum. However, the lack of detection of atypical cells on impression cytology has a high negative predictive value for ocular surface squamous neoplasia. Integration of impression cytology in the long-term management of high-risk patients, such as patients with xeroderma pigmentosum, can avoid unnecessary diagnostic biopsies.

Cell block practices in European cytopathology laboratories

BACKGROUND

There are numerous methods and procedures described for the preparation of cell blocks (CBs) from cytological samples. The objective of this study was to determine current practices and issues with CBs in European laboratories.

METHODS

A link to an online survey, with 11 questions about CB practices, was distributed to cytology laboratories via participants of United Kingdom National External Quality Assurance Service for Cellular Pathology Techniques and national representatives in the European Federation of Cytology Societies.

RESULTS

A total of 402 laboratories responded completely (337/402, 84%) or partially (65/402, 16%) to the survey by February 4, 2022. The most common CB practice is embedding cell pellets using plasma and thrombin (23.3%), agar (17.1%), Shandon/Epredia Cytoblock (11.4%), HistoGel (7.9%), and Cellient (3.5%). Other methods such as CytoFoam, albumin, gelatin, Cytomatrix, and collodion bags are rarely used (1.0%, 0.7%, 0.7%, 0.3%, and 0.2%, respectively). CBs are also prepared from naturally occurring clots or tissue fragments (29.5%) and cells scraped from unstained or prestained smears (4.4%). The most frequent issues with the CBs in a daily cytology practice are low cellularity (248/402, 62%) and dispersed cells (89/402, 22%), regardless of the CBs preparation method or how the samples for embedding were selected.

CONCLUSIONS

There is a great variability in CB practices in European laboratories with low cellular CBs as the main issue. Additional studies are mandatory to evaluate and improve performance and cellular yield of CBs.

An engineered cell line with a hRpn1-attached handle to isolate proteasomes

Regulated protein degradation in eukaryotes is performed by the 26S proteasome, which contains a 19-subunit regulatory particle (RP) that binds, processes, and translocates substrates to a 28-subunit hollow core particle (CP) where proteolysis occurs. In addition to its intrinsic subunits, myriad proteins interact with the proteasome transiently, including factors that assist and/or regulate its degradative activities. Efforts to identify proteasome-interacting components and/or to solve its structure have relied on over-expression of a tagged plasmid, establishing stable cell lines, or laborious purification protocols to isolate native proteasomes from cells. Here, we describe an engineered human cell line, derived from colon cancer HCT116 cells, with a biotin handle on the RP subunit hRpn1/PSMD2 (proteasome 26S subunit, non-ATPase 2) for purification of 26S proteasomes. A 75-residue sequence from Propionibacterium shermanii that is biotinylated in mammalian cells was added following a tobacco etch virus protease cut site at the C terminus of hRpn1. We tested and found that 26S proteasomes can be isolated from this modified HCT116 cell line by using a simple purification protocol. More specifically, biotinylated proteasomes were purified from the cell lysates by using neutravidin agarose resin and released from the resin following incubation with tobacco etch virus protease. The purified proteasomes had equivalent activity in degrading a model ubiquitinated substrate, namely ubiquitinated p53, compared to commercially available bovine proteasomes that were purified by fractionation. In conclusion, advantages of this approach to obtain 26S proteasomes over others is the simple purification protocol and that all cellular proteins, including the tagged hRpn1 subunit, remain at endogenous stoichiometry.

Relationship between a deep learning model and liquid-based cytological processing techniques

OBJECTIVE

Artificial intelligence (AI)-based cytopathology studies conducted using deep learning have enabled cell detection and classification. Liquid-based cytology (LBC) has facilitated the standardisation of specimen preparation; however, cytomorphology varies according to the LBC processing technique used. In this study, we elucidated the relationship between two LBC techniques and cell detection and classification using a deep learning model.

METHODS

Cytological specimens were prepared using the ThinPrep and SurePath methods. The accuracy of cell detection and cell classification was examined using the one- and five-cell models, which were trained with one and five cell types, respectively.

RESULTS

When the same LBC processing techniques were used for the training and detection preparations, the cell detection and classification rates were high. The model trained on ThinPrep preparations was more accurate than that trained on SurePath. When the preparation types used for training and detection were different, the accuracy of cell detection and classification was significantly reduced (P < 0.01). The model trained on both ThinPrep and SurePath preparations exhibited slightly reduced cell detection and classification rates but was highly accurate.

CONCLUSIONS

For the two LBC processing techniques, cytomorphology varied according to cell type; this difference affects the accuracy of cell detection and classification by deep learning. Therefore, for highly accurate cell detection and classification using AI, the same processing technique must be used for both training and detection. Our assessment also suggests that a deep learning model should be constructed using specimens prepared via a variety of processing techniques to construct a globally applicable AI model.

Density-Based Fractionation of Cell-Conditioned Medium to Prepare Proteomics Grade Extracellular Vesicles

The identification of the molecular composition of extracellular vesicles (EV) by omics approaches, including proteomics, requires the separation of EV from non-EV confounding factors present in the source biofluid. In this protocol, we present the sequential implementation of density gradient ultracentrifugation and size-exclusion chromatography to prepare EV from cell-conditioned medium with high specificity and repeatability. This approach enables the recovery of intact purified EV suited for downstream functional assays and biomarker discovery by omics approaches.

Generative adversarial network enables rapid and robust fluorescence lifetime image analysis in live cells

Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool to quantify molecular compositions and study molecular states in complex cellular environment as the lifetime readings are not biased by fluorophore concentration or excitation power. However, the current methods to generate FLIM images are either computationally intensive or unreliable when the number of photons acquired at each pixel is low. Here we introduce a new deep learning-based method termed flimGANE (fluorescence lifetime imaging based on Generative Adversarial Network Estimation) that can rapidly generate accurate and high-quality FLIM images even in the photon-starved conditions. We demonstrated our model is up to 2,800 times faster than the gold standard time-domain maximum likelihood estimation (TD_MLE) and that flimGANE provides a more accurate analysis of low-photon-count histograms in barcode identification, cellular structure visualization, Förster resonance energy transfer characterization, and metabolic state analysis in live cells. With its advantages in speed and reliability, flimGANE is particularly useful in fundamental biological research and clinical applications, where high-speed analysis is critical.

Protocol to measure contraction, calcium, and action potential in human-induced pluripotent stem cell-derived cardiomyocytes

Multiple strategies have been developed to efficiently differentiate human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Here, we describe a protocol for measuring three key functional parameters of hiPSC-CMs, including contractile function, calcium (Ca²⁺) handling, and action potential.

For complete details on the use and execution of this protocol, please refer to Zhang et al. (2021).

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Automated measurement of hiPSC-CM contractile function

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Single-cell calcium imaging of hiPSC-CMs loaded with Fura-2 AM

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Imaging-based action potential measurement of hiPSC-CMs

Kinobead Profiling Reveals Reprogramming of BCR Signaling in Response to Therapy within Primary CLL Cells

PURPOSE

B-cell receptor (BCR) signaling is critical for the pathogenesis of chronic lymphocytic leukemia (CLL), promoting both malignant cell survival and disease progression. Although vital, understanding of the wider signaling network associated with malignant BCR stimulation is poor. This is relevant with respect to potential changes in response to therapy, particularly involving kinase inhibitors. In the current study, we describe a novel high-resolution approach to investigate BCR signaling in primary CLL cells and track the influence of therapy on signaling response.

EXPERIMENTAL DESIGN

A kinobead/mass spectrometry-based protocol was used to study BCR signaling in primary CLL cells. Longitudinal analysis of samples donated by clinical trial patients was used to investigate the impact of chemoimmunotherapy and ibrutinib on signaling following surface IgM engagement. Complementary Nanostring and immunoblotting analysis was used to verify our findings.

RESULTS

Our protocol isolated a unique, patient-specific signature of over 30 kinases from BCR-stimulated CLL cells. This signature was associated with 13 distinct Kyoto Encyclopedia of Genes and Genomes pathways and showed significant change in cells from treatment-naïve patients compared with those from patients who had previously undergone therapy. This change was validated by longitudinal analysis of clinical trials samples where BCR-induced kinome responses in CLL cells altered between baseline and disease progression in patients failing chemoimmunotherapy and between baseline and treatment in patients taking ibrutinib.

CONCLUSIONS

These data comprise the first comprehensive proteomic investigation of the BCR signaling response within CLL cells and reveal unique evidence that these cells undergo adaptive reprogramming of this signaling in response to therapy.

A zygote-based assay to evaluate intranuclear shuttling in S. cerevisiae

It is often necessary to learn whether macromolecules occupy a fixed place in cells. This protocol makes it possible to learn whether individual nucleolar proteins in S. cerevisiae remain in place or depart from and return to the nucleolus. The protocol uses early zygotes in which parental nucleoli are separate for at least one hour. The protocol demonstrates that the localization of many nucleolar proteins is in fact highly dynamic. Photobleaching is not required.

For complete details on the use and execution of this protocol, please refer to Tartakoff et al. (2021).

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The mobility of proteins within the yeast nucleus can be judged by constructing zygotes

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The assay requires minimal equipment other than a sensitive fluorescent microscope

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The protocol can be completed within one day once appropriate cells are available

An optimized protocol with a stepwise approach to identify specific nuclear receptor ligands from cultured mammalian cells

Here, we describe an optimized protocol to identify specific nuclear receptor ligands. First, to rule out any compound interference with luciferase activity per se, we describe an in vitro assay assessing potential inhibition or activation of luciferase enzymatic activity. Second, to comply with EMA and FDA guidelines to mitigate drug-drug interactions, we detail assays assessing constitutive androstane receptor (CAR) and pregnane X receptor (PXR) activation ability. Finally, to minimize off-target detection effects, we describe the use of mammalian one- (or two-) hybrid systems. For complete details on the use and execution of this protocol, please refer to Hering et al. (2018).

The Value of Ultrasound-Guided Fine-Needle Aspiration Cytology Combined with Puncture Feeling in the Diagnosis of Thyroid Nodules

INTRODUCTION

There are few studies on the role of puncture feeling in thyroid nodules during ultrasound-guided fine-needle aspiration cytology (US-FNAC), although it is expected to become a new predictive technique. We aimed to analyze the importance of puncture feeling in combination with US-FNAC and investigate whether it can be used as an indicator to predict the nature of thyroid nodules.

MATERIALS AND METHODS

From January 1, 2018, to October 31, 2020, a total of 623 thyroid nodules were included. Puncture feeling was classified as "soft," "hard," or "hard with grittiness." The correlation between puncture feeling and postoperative pathology and the diagnostic value of FNAC combined with puncture feeling were analyzed, and the influence of thyroid nodule size on puncture feeling, FNAC, and FNAC combined with puncture feeling was studied. We further explored the correlation between puncture feeling and histopathology in Bethesda III and IV thyroid nodules.

RESULTS

There was a significant correlation between puncture feeling and postoperative pathology (p < 0.001). The sensitivity, negative predictive value, and total coincidence rate of US-FNAC combined with puncture feeling for the diagnosis of thyroid nodules were higher than those of US-FNAC alone (96.1, 83.6, and 94.7% vs. 89.0, 65.5, and 89.7%, respectively). Thyroid nodule size was the influencing factor for puncture feeling, FNAC, and FNAC combined with puncture feeling (p < 0.05 for all). The area under the curve for puncture feeling, FNAC, and FNAC combined with puncture feeling for thyroid nodules of size ≤1 cm was greater than for modules of size >1 cm. Puncture feeling was of great value in diagnosing Bethesda III thyroid nodules (p < 0.001), and all Bethesda IV thyroid nodules had puncture feeling of soft.

CONCLUSION

Puncture feeling is of great value during US-FNAC. "Hard" and "hard with grittiness" were indicators for malignancy, while "soft" indicated that the thyroid nodule was likely to be benign. The diagnostic value of US-FNAC combined with puncture feeling for thyroid nodules is higher than US-FNAC alone, especially when nodule size is ≤1 cm. Puncture feeling is of great value in predicting the nature of Bethesda III thyroid nodules.

Cell Block and Its Impact in the Diagnosis of Jaw Lesions over Fine Needle Aspiration Cytology

OBJECTIVES

To determine the role and efficacy of fine needle aspiration cytology (FNAC) and cell block in diagnosis of jaw lesions and compare the agreement between FNAC and cell block to predict the diagnosis.

METHOD

The sample comprised 51 cases, including 12 odontogenic keratocysts (OKCs), 8 ameloblastomas, 22 radicular cysts, 7 dentigerous cysts, and 1 each of intraosseous mucoepidermoid carcinoma (MEC) and adenomatoid odontogenic tumor (AOT). FNAC samples remaining after hematoxylin and eosin (H&amp;E)-stained cytosmear diagnosis were centrifuged at 3,000 rpm for 10 min. The supernatant was discarded and sediment mixed with 2-3 mL alcohol and filtered. To this, 10% formalin was added, filtered, taken for routine processing, and stained with H&amp;E. The result of FNAC smear and cell block was compared with histopathological diagnosis.

RESULTS

On cytological examination of the smears, 7 OKCs and 22 radicular cysts were diagnosed, whereas ameloblastomas, AOT, intraosseous MEC, and dentigerous cysts were not. This gave an agreement of 56.8% with the biopsy reports. Cell block sections stained with H&amp;E of 12 OKCs, 22 radicular cysts, 1 MEC, and 3 cases of ameloblastoma offered a diagnosis in accordance with the biopsies giving an agreement of 74.5%, while dentigerous cyst and AOT failed to do so. In comparison with FNAC, additionally 5 cases of OKC and 1 of MEC could be detected, and in ameloblastoma, out of 8 cases, only 3 yielded a concordant diagnosis through the cell block technique.

CONCLUSION

In comparison with FNAC, the architectural pattern and the morphology of the cells were better preserved by the cell block technique. This substantiates that cell block could be used as an ancillary technique to aid in definitive diagnosis of head and neck swellings.

Elevation of Intra-Cellular Calcium in Nucleus Pulposus Cells with Micro-Pipette-Guided Ultrasound

Modulation of intra-cellular calcium by ultrasound offers a possible means for therapeutic applications. One such possibility is the modulation of nucleus pulposus cells as a preventive measure for inter-vertebral disc degeneration. We report a cellular stimulation device (micro-pipette ultrasound) using a glass micro-pipette as a waveguide to deliver ultrasound through the pipette tip and to elevate intra-cellular calcium in nucleus pulposus cells. The device generates two relevant stimuli at the cellular level: ultrasound propagation throughout the cell and acoustic streaming on the apical side. Ultrasound is radiated from a tip of a few microns, and its amplitude is proportional to the input voltage; acoustic streaming can be controlled by the duty factor. The novelty of the device is to impose a unique cellular loading: shear stress on cell apical surfaces combined with compressional waves propagating through the cells. G protein-coupled receptors and acid-sensing ion channel 3 were shown to play a role in calcium elevation by micro-pipette ultrasound in nucleus pulposus cells. Our results demonstrate that micro-pipette ultrasound can be an effective tool to elevate intra-cellular calcium levels in different cells, facilitating the identification of different mechanoreceptors in action.

Fine-Needle Aspiration Cytology versus Core-Needle Biopsy for Breast Lesions: A Dilemma of Superiority between the Two

INTRODUCTION

Core-needle biopsy (CNB) is a minimally invasive procedure used in preoperative diagnosis of breast lumps. It has been seen that in few years, the CNB seems to be replacing the fine-needle aspiration cytology (FNAC), although no study had yet conclusively proved a superiority of one over the other.

AIMS AND OBJECTIVES

The aim of this study was to study the cytohistological spectrum of palpable breast lesions and to evaluate the diagnostic accuracy of FNAC versus CNB for breast lesions.

MATERIALS AND METHODS

The study was a cross-sectional study conducted in the Department of Pathology and Surgery, over a period of 1 year in 152 patients. All the patients were subjected to FNAC and CNB. Cytosmears were stained with May-Grunwald Giemsa and hematoxylin and eosin was done on CNB and excision biopsy (EB) specimens. Sensitivity and specificity were calculated in percentage with 95% confidence interval with reference to CNB/surgical specimens. Kappa statistics were used to compare the level of agreement between FNAC versus CNB and CNB versus surgical specimens.

RESULTS

A total of 152 patients were taken for FNAC and CNB. EB was performed in only 104 patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FNAC verses CNB in correlation with subsequent histopathology were found to be (93.40 vs. 94.06%), (97.50 vs. 100.00%), (99.00 vs. 100.00%), (84.78 vs. 33.33%), and (94.52 vs. 94.23%), respectively.

CONCLUSION

CNB has overcome the pitfall of FNAC but CNB cannot replace FNAC but both procedures are complementary to each other.

Rapid Cell Transfer by Means of Nylon Mesh to Improve Cellular Diagnosis: The Role of Immunocytochemistry

Immunocytochemistry (ICC) is an important ancillary technique in clinical cytology for not only identifying and characterizing tumor cells but also gaining prognostic or therapeutic information. Although cell blocks are often prepared for immunocytochemical evaluation of body cavity fluid and fine-needle aspiration specimens, they are not suitable for hypocellular samples. Liquid-based cytology can help prepare additional smears from residual cytological specimens. However, since conventional methods are used for nongynecological specimens in most laboratories, ICC is often limited by the number of cytological smears. Cell transfer methods permit to evaluate several immunocytochemical markers in a single cytological smear. Yet, these methods have some limitations; for example, they are time-consuming (about 3-40 h) and medium membranes with their attached cells are occasionally stretched or torn when peeled off the slides. Therefore, in an attempt to solve these problems, we developed a rapid and reliable cell transfer method using a nylon mesh. Our method requires no special equipment or reagent and can significantly reduce the turnaround time, as compared to previous methods.

A diacylglycerol photoswitching protocol for studying TRPC channel functions in mammalian cells and tissue slices

Small molecular probes designed for photopharmacology and opto-chemogenetics are rapidly gaining widespread recognition for investigations of transient receptor potential canonical (TRPC) channels. This protocol describes the use of three photoswitchable diacylglycerol analogs—PhoDAG-1, PhoDAG-3, and OptoDArG—for ultrarapid activation and deactivation of native TRPC2 channels in mouse vomeronasal sensory neurons and olfactory type B cells, as well as heterologously expressed human TRPC6 channels. Photoconversion can be achieved in mammalian tissue slices and enables all-optical stimulation and shutoff of TRPC channels.

For complete details on the use and execution of this protocol, please refer to Leinders-Zufall et al. (2018).

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DAG photoswitching enables ultrarapid activation and deactivation of TRPC channels

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Multiple photoswitchable DAG analogs are now available

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DAG photoconversion is sufficient for the gating of TRPC2, TRPC3, and TRPC6

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Photoswitching combined with Ca²⁺ imaging enables all-optical stimulation and recording

Algorithmic assessment of cellular senescence in experimental and clinical specimens

The development of genetic tools allowed for the validation of the pro-aging and pro-disease functions of senescent cells in vivo. These discoveries prompted the development of senotherapies-pharmaceutical interventions aimed at interfering with the detrimental effect of senescent cells-that are now entering the clinical stage. However, unequivocal identification and examination of cellular senescence remains highly difficult because of the lack of universal and specific markers. Here, to overcome the limitation of measuring individual markers, we describe a detailed two-phase algorithmic assessment to quantify various senescence-associated parameters in the same specimen. In the first phase, we combine the measurement of lysosomal and proliferative features with the expression of general senescence-associated genes to validate the presence of senescent cells. In the second phase we measure the levels of pro-inflammatory markers for specification of the type of senescence. The protocol can help graduate-level basic scientists to improve the characterization of senescence-associated phenotypes and the identification of specific senescent subtypes. Moreover, it can serve as an important tool for the clinical validation of the role of senescent cells and the effectiveness of anti-senescence therapies.

Role of fine-needle aspiration cytology in evaluating thyroid nodules. A retrospective study from a tertiary care center of Western region, Saudi Arabia

OBJECTIVES

To evaluate the accuracy and e cacy of ne-needle aspiration cytology (FNAC) in diagnosing thyroid nodules, correlating it with the histopathological findings.

METHODS

A retrospective evaluation of 314 patients was undertaken at a tertiary referral center of King Abdullah Medical City (KAMC), Makkah, Kingdom of Saudi Arabia, between 2010-2019. Patients who presented with thyroid swellings underwent ultrasonography and FNAC. If indicated, surgery was performed. The FNAC findings were compared to the final histopathological reports.

RESULTS

The findings for FNAC from our data set of 314 patients showed a sensitivity value of 79.8%, specificity of 82.1%, accuracy of 74.8%, positive predictive value of 74.8%, and negative predictive value of 85.9%. Conclusion: Our study showed that FNAC has high sensitivity and speci city in the initial evaluation of patients with thyroid nodules. When guided by ultrasonography, the accuracy can be markedly improved. Molecular markers once widely available can improve the diagnostic power of FNAC to be no less than the histopathologic evaluation of thyroid tissue.

Ratiometric pH sensing by fluorescence resonance energy transfer-based hybrid semiconducting polymer dots in living cells

Intracellular pH plays a significant role in all cell activities. Due to their precise imaging capabilities, fluorescent probes have attracted much attention for the investigation of pH-regulated processes. Detecting intracellular pH values with high throughput is critical for cell research and applications. In this work, hybrid semiconducting polymer dots (Pdots) were developed and characterized and were applied for cell imaging and exclusive ratiometric sensing of intracellular pH values. The reported Pdots were prepared by blending a synthesized block polymer (P_OMF) and a semiconducting polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) to construct a fluorescence resonance energy transfer system for ratiometric sensing. Pdots showed many advantages, including high brightness, excellent photostability and biocompatibility, giving the pH probe high sensitivity and good stability. Our results proved the capability of P_OMF-MEHPPV Pdots for the detection of pH in living cells.

A comparison of the analysis of 3 types of body fluids using the XN-350 hematology analyzer versus light microscopy assessment

We evaluated the capacity of the XN-350 instrument to analyze 3 different types of body fluid samples under "body fluid mode."The performance of XN-350 was evaluated in terms of precision, carryover, limit of blank, limit of detection, limit of quantification, and linearity. Cell enumeration and differential data produced by the XN-350 were compared to manual chamber counting results in 63 cerebrospinal fluid (CSF), 51 ascitic fluid, and 51 pleural fluid (PF) samples. Comparisons between XN-350 versus Cytospin data were also performed in PF samples.The precision, carry-over, limit of blank, and linearity of the XN-350 were acceptable. The limits of detection for white blood cells (WBCs) and red blood cells were 1.0/μL, and 1,000.0/μL, respectively; the corresponding limits of quantitation (LOQs) were 5.0/μL and 2,000.0/μL, respectively. The XN-350's cell enumeration and differential counting correlated well with those of manual chamber counting for all 3 sample types (except for differential counting in CSF samples), particularly parameters involving monocytes (r = 0.33) and mononuclear cells (MO- body fluid [BF]; r = 0.26), as well as total cell (TC-BF) enumeration (r = 0.50) and WBC-BF (r = 0.50) in PF samples. The MO-BF in CSF samples differed significantly from manual chamber counting results, but neither TC-BF nor WBC-BF in PF samples did. The XN-350 also showed good correlations with Cytospin analyses for differential counting of neutrophils, lymphocytes, and monocytes in PF samples. The differential counting of eosinophils via the XN-350 and Cytospin were not significantly correlated, but the difference between them was not significant.The XN-350 is an acceptable alternative to manual fluid analysis. Samples with low cellularity around the LOQ should be checked manually. Moreover, manual differential counting should be performed on CSF samples, particularity those with low cell numbers.

Renal medullary carcinoma involving serous cavity fluids: a cytomorphologic study of 12 cases

INTRODUCTION

Renal medullary carcinoma (RMC) is a highly lethal adenocarcinoma with a propensity for widespread metastatic disease in young patients. It is strongly associated with sickle cell trait and shows the loss of SMARCB1 (also known as INI1 or BAF47) protein expression. In the present study, we reviewed a series of 12 patients for whom the cytology specimens played a significant role in patient treatment.

MATERIALS AND METHODS

We performed a retrospective case review of patients with a history of RMC from 3 large tertiary care pathology practices.

RESULTS

A total of 12 patients were identified with histologically confirmed RMC who had had pleural, pericardial, or urine specimens involved by their disease or had undergone initial kidney fine needle aspiration. Patient age ranged from 13 to 37 years (median, 21.5 years). All 12 patients were black or of African descent, and 10 had a confirmed history of sickle cell trait. Of the 12 patients, 11 (92%) had fluid specimens involved by metastatic tumor at some point in their clinical course, and 4 (33%) had initially presented with pericardial and/or pleural effusions or urine specimens that were positive for malignancy. Cytologic examination predominantly showed fragments of 3-dimensional "tumor balls" with smooth borders, fine pale cytoplasm with vacuolization, and highly pleomorphic nuclei with irregular nuclear membranes and coarse to vesicular chromatin and single prominent nucleoli.

CONCLUSIONS

The cytomorphology of RMC involving serous fluids is nonspecific and in keeping with metastatic high-grade adenocarcinoma. In a young patient presenting with no history of malignancy and a pleural or pericardial effusion, triaging the material for ancillary studies and a nuanced assessment of patient history and radiologic findings will be critical.

Quantitatively Controlled Intercellular Mitochondrial Transfer by Cell Fusion-Based Method Using a Microfluidic Device

Quantitative control of mitochondrial transfer is a promising approach for genetic manipulation of mitochondrial DNA (mtDNA) because it enables precise modulation of heteroplasmy. Furthermore, single mitochondrion transfer from a mtDNA mutation-accumulated cell to a mtDNA-less (ρ⁰) cell potentially achieves homoplasmy of mutated mtDNA. Here we describe the method for quantitative control of mitochondrial transfer including achieving single mitochondrion transfer between live single cells using a microfluidic device.

Isolation of Mitochondria from Retinal Pigment Epithelial Cell Cultures and an Application of High-Resolution Respirometric Assay (XFe96 Seahorse Assay)

Intracellular Ca²⁺ is strictly regulated to maintain optimal levels for function of cellular organelles as well as mitochondrial respiratory signaling at the tricarboxylic acid cycle and electron transport chain level. Optimal Ca²⁺ concentration for these processes vary between cell types. Furthermore, exposure of mitochondria to sustained, elevated levels of Ca²⁺ induces mitochondrial Ca²⁺ overload and damage to mitochondrial oxidative phosphorylation and ATP production. Isolated mitochondria are widely used to study mitochondrial physiology and drug effects on mitochondrial metabolism and respiratory function. However, isolated mitochondria are easily damaged during the mitochondrial isolation process. The present article describes a mitochondrial isolation method using Ca²⁺-chelation to minimize mitochondrial damage. We follow up the isolation process with an application that requires an optimized buffer Ca²⁺ concentration: the characterization of their respiratory function using a high-resolution respirometric assay.

Extraction of Functional Mitochondria Based on Membrane Stiffness

The abnormal functionality of mitochondria has been linked to many life-threatening diseases such as cancers, failure of cardiovascular functions, and neurodegenerative disorders. Therefore, in vitro analysis of mitochondria has garnered great interest for understanding the mechanism of mitochondrial dysfunction-related disease development and therapeutics. However, due to the intrinsic heterogeneity of cell membrane stiffness, it remains challenging to standardize the protocols for the extraction of mitochondria and adequate disruption of the cellular membrane while retaining the functionality of mitochondria. We have previously developed a microfluidics-based cell shredder capable of serving the purpose. In this protocol, we describe the step-by-step procedures to empirically identify the threshold shear stress using this microfluidics-based cell shredder for mitochondrial extraction. The optimal shear stress to disrupt human embryonic kidney cell (HEK 293) and mice muscle cell (C2C12) has been characterized at around 16.4 Pa, whereas cell lines with stiffer membrane stiffness, for example, neuroblastoma cells (SH-SY5Y), require 27.4 Pa to effectively lyse the cells. This protocol also provides detailed procedures to determine the quality of extracted mitochondria based on the membrane potential and the integrity of extracted mitochondria. A comparison with the widely employed Dounce homogenizer has shown that the proposed microscale cell shredder can yield at least 40% more functional mitochondria and retain higher integrity regarding extracted mitochondria than the counterparts extracted from Dounce homogenizer, especially for low cell concentrations (5-20 × 10⁴ cells/mL) and small sample volume (<200 μL).

How do moth and butterfly taste?-Molecular basis of gustatory receptors in Lepidoptera

Insect gustatory system plays a central role in guiding insect feeding behaviors, insect-plant interactions and coevolutions. Gustatory receptors (GRs) form the interface between the insect taste system and their environment. Previously, most studies on insect GRs are focused on Drosophila; much less attention has been paid to Lepidoptera species, which consist of a large number of serious agricultural crop pests. With the exceptional advances in the next generation sequencing (NGS), cellular biology, RNA interference (RNAi), and clustered regularly interspaced short palindromic repeats (CRISPR) technologies in recent years, extraordinary progresses have been achieved elucidating the molecular mechanisms of Lepidopteran GRs. In this review, we highlighted these advances, discussed what these advances have revealed and provide our new insights into this field.

Digital Multiplexed Gene Expression Analysis of mRNA and miRNA from Routinely Processed and Stained Cytological Smears: A Proof-of-Principle Study

OBJECTIVE

Although transcriptomic assessments of small samples using high-throughput techniques are usually performed on fresh or frozen tissues, there is a growing demand for those performed on stained cellular specimens already used for diagnostic purposes.

STUDY DESIGN

The possibility of detecting mRNAs and microRNAs (miRNAs) from routinely processed cytological samples using nCounter® technology was explored. Fresh samples from pleural and peritoneal effusions were analyzed using 2 parallel methods: samples were smeared and routinely stained using the May-Grünwald-Giemsa or Diff-Quik® method and mounted using conventional methods, and they were also studied following a snap freezing method, in which samples were maintained at -80°C until use. mRNAs and miRNAs were assessed and compared after total RNA extraction from both routinely processed samples and their matched frozen controls.

RESULTS

A good concordance was found between the gene expression measured in routinely processed samples and their matched frozen controls for the majority of mRNAs and miRNAs tested. However, the standard deviation of low-expressed miRNA was high.

CONCLUSIONS

Although nCounter® technology is a robust method to measure and characterize both mRNAs and miRNAs from routinely processed cytological samples, caution is recommended for the interpretation of low-expressed miRNA.

Quantitative Approaches for Scoring in vivo Neuronal Aggregate and Organelle Extrusion in Large Exopher Vesicles in C. elegans

Toxicity of misfolded proteins and mitochondrial dysfunction are pivotal factors that promote age-associated functional neuronal decline and neurodegenerative disease across species. Although these neurotoxic challenges have long been considered to be cell-intrinsic, considerable evidence now supports that misfolded human disease proteins originating in one neuron can appear in neighboring cells, a phenomenon proposed to promote pathology spread in human neurodegenerative disease. C. elegans adult neurons that express aggregating proteins can extrude large (~4 µm) membrane-surrounded vesicles that can include the aggregated protein, mitochondria, and lysosomes. These large vesicles are called "exophers" and are distinct from exosomes (which are about 100x smaller and have different biogenesis). Throwing out cellular debris in exophers may occur by a conserved mechanism that constitutes a fundamental, but formerly unrecognized, branch of neuronal proteostasis and mitochondrial quality control, relevant to processes by which aggregates spread in human neurodegenerative diseases. While exophers have been mostly studied in animals that express high copy transgenic mCherry within touch neurons, these protocols are equally useful in the study of exophergenesis using fluorescently tagged organelles or other proteins of interest in various classes of neurons. Described here are the physical features of C. elegans exophers, strategies for their detection, identification criteria, optimal timing for quantitation, and animal growth protocols that control for stresses that can modulate exopher production levels. Together, details of protocols outlined here should serve to establish a standard for quantitative analysis of exophers across laboratories. This document seeks to serve as a resource in the field for laboratories seeking to elaborate molecular mechanisms by which exophers are produced and by which exophers are reacted to by neighboring and distant cells.

Protocol for Measurement of Oxygen Consumption Rate In Situ in Permeabilized Cardiomyocytes

Analysis of mitochondrial respiration function represented by the oxygen consumption rate is necessary for assessing mitochondrial respiration function. This protocol describes steps to evaluate the respiration function of mitochondria in situ in saponin-permeabilized cardiomyocytes. In permeabilized cells, mitochondria are in a relatively integrated cellular system, and mitochondrial respiration is more physiologically relevant than isolated mitochondria. For complete details on the use and execution of this protocol, please refer to Gong et al. (2015a) and Gong et al. (2015b).

Bethesda System Categories of Fine Needle Aspiration Cytology Are Not Associated with Thyroid Nodule Location: A Single Institution Experience

INTRODUCTION

Thyroid isthmus is defined as the thin band connecting thyroid tissue between both lateral thyroid lobes. Recently, a possible association between thyroid nodules located in the isthmus and malignancy was proposed. The aim of this study was to compare the frequency of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) categories between nodules from the isthmus and nodules from both thyroid lobes.

METHODS

All fine needle aspiration cytology procedures performed between January 2016 and December 2019 at the Pathology Institute of Araçatuba, São Paulo, Brazil, were analyzed. For each nodule, at least 2 conventional slides were produced (1 stained by Giemsa and the other by hematoxylin and eosin). All cases were reported according to the TBSRTC. Clinical information (gender, age, and localization) and ultrasound data (size of nodules) were collected from medical requisition forms. To assess the association between the frequency of TBSRTC categories and nodule location, univariate analysis was performed using the χ2 test or Fisher's exact test, as appropriate. A p value <0.05 was considered statistically significant. Nodules located in transition between the isthmus and a right or left lobe were included in the isthmus group.

RESULTS

Considering the p value between the TBSRTC categories and thyroid nodule location, statistic association was not observed: nondiagnostic or unsatisfactory (p = 0.1442), atypia of undetermined significance or follicular lesion of undetermined significance (p = 0.3296), follicular neoplasm or suspicious for a follicular neoplasm (p = 0.0817), suspicious for malignancy (p = 0.8464), and malignant (p = 0.1082).

CONCLUSION

In the studied population, nodules located in the isthmus were not related to any Bethesda System category.

A Novel Edge Effect Detection Method for Real-Time Cellular Analyzer Using Functional Principal Component Analysis

Real-time cellular analyzer (RTCA) has been generally applied to test the cytotoxicity of chemicals. However, several factors impact the experimental quality. A non-negligible factor is the abnormal time-dependent cellular response curves (TCRCs) of the wells located at the edge of the E-plate which is defined as edge effect. In this paper, a novel statistical analysis is proposed to detect the edge effect. First, TCRCs are considered as observations of a random variable in a functional space. Then, functional principal component analysis (FPCA) is adopted to extract the principal component (PC) functions of the TCRCs, and the first and second PCs of these curves are selected to distinguish abnormal TCRCs. The average TCRC of the inner wells with the same culture environment is set as the standard. If the distance between the scoring point of the standard curve and one designated scoring point exceeds the defined threshold, the corresponding TCRC of the designated point should be removed automatically. The experimental results demonstrate the effectiveness of the proposed algorithm. This method can be used as a standard method to resolve general time-dependent series issues.

Fast and multiplexed superresolution imaging with DNA-PAINT-ERS

DNA points accumulation for imaging in nanoscale topography (DNA-PAINT) facilitates multiplexing in superresolution microscopy but is practically limited by slow imaging speed. To address this issue, we propose the additions of ethylene carbonate (EC) to the imaging buffer, sequence repeats to the docking strand, and a spacer between the docking strand and the affinity agent. Collectively termed DNA-PAINT-ERS (E = EC, R = Repeating sequence, and S = Spacer), these strategies can be easily integrated into current DNA-PAINT workflows for both accelerated imaging speed and improved image quality through optimized DNA hybridization kinetics and efficiency. We demonstrate the general applicability of DNA-PAINT-ERS for fast, multiplexed superresolution imaging using previously validated oligonucleotide constructs with slight modifications.

Methods for studying protein targeting to and within the chloroplast

Distinct protein complements impart each of the chloroplast's three membranes and three aqueous spaces with specific functions essential for plant growth and development. Chloroplasts capture light energy, synthesize macromolecular building blocks and specialized metabolites, and communicate environmental signals to the nucleus. Establishing and maintaining these processes requires approximately 3000 proteins derived from nuclear genes, constituting approximately 95% of the chloroplast proteome. These proteins are imported into chloroplasts from the cytosol, sorted to the correct subcompartment, and assembled into functioning complexes. In vitro import assays can reconstitute these processes in isolated chloroplasts. We describe methods for monitoring in vitro protein import using Pisum sativum chloroplasts and for protease protection, fractionation, and native protein electrophoresis that are commonly combined with the import assay. These techniques facilitate investigation of the import and sorting processes, of where a protein resides, and of how that protein functions.

Cytomorphological pattern analysis of tubercular lymphandenopathies

BACKGROUND

The spectrum of morphological pattern in tubercular lymphandenopathies was observed to study the various cytomorphological patterns and their correlation with acid fast bacilli.

METHODS

FNAC smears of 210 cases of granulomatous lymphadenitis stained with Giemsa, Pap and haematoxylin and eosin were used to analyze cytomorphological pattern and Zeihl Neelsen stained smears for acid fast bacilli (AFB) detection.

RESULTS

193 cases with necrotising granulomatous inflammation or positive acid fast bacilli were included. Age group 21-30 years was most common (38.3%) followed by age group 11-20 years (30.05%). Females constituted 66.3% of patients and 33.7% were male. Overall the most common pattern in present study was pattern A (Epitheloid granuloma with caseous necrosis 33.7% followed by pattern B (caseous necrosis with few scattered epitheloid histiocytes and lymphocytes) 31.1% and pattern C (caseous necrosis with suppurative inflammation) 30.6%, followed by pattern D (Caseous necrosis only) (3.6%) and pattern E (non necrotising epitheloid granuloma with positive acid fast bacilli) (1.03%). Acid fast bacilli were demonstrable in 175 cases (90.7%). Amongst the acid fast bacilli positive cases highest bacillary load 3+ grade was seen in pattern C in 6/59 (10.16%) cases.

CONCLUSION

FNAC is a simple useful tool and should be attempted in all cases of lymphandenopathies. It helps in establishing a diagnosis of tubercular etiology based on its morphological patterns however demonstration of acid fast bacilli on aspirated material confirms the diagnosis.

Determination of high-risk HPV status of head and neck squamous cell carcinoma using the Roche cobas HPV test on cytologic specimens and acellular supernatant fluid

BACKGROUND

High-risk human papillomavirus-positive (hrHPV+) oropharyngeal squamous cell carcinomas comprise a subset of head and neck squamous cell carcinomas (HNSCCs) with a distinct biology and prognosis. Commonly, the diagnosis of HNSCC is rendered on fine-needle aspiration (FNA). Because cell blocks may be insufficient for determining HPV status using microscopy-based techniques, the ability of liquid-based assays was examined in the current study.

METHODS

The performance of the Roche cobas 4800 platform was evaluated on the FNA material from the cell pellet and corresponding cell-free supernatant fluid specimens of primary and metastatic HNSCCs. These results were compared with the p16 immunostain result from the histologic material obtained from the same patient. Discrepant cases were adjudicated using hrHPV RNA in situ hybridization.

RESULTS

A total of 41 samples (23 primary tumors and 18 lymph node metastases) were acquired from 34 patients with HNSCC. Primary tumors included the oropharynx (20 samples), oral cavity (13 samples), larynx (3 samples), and skin (3 samples). In 2 cases, a primary tumor could not be identified. Twenty-three samples (56%) were found to be p16 positive by immunohistochemistry. Twenty-two samples were found to be positive on cobas hrHPV testing from both cell pellet and cell-free supernatant fluid. Two cell-free supernatant fluid specimens yielded indeterminate cobas results. At the time additional hrHPV RNA in situ hybridization analysis was performed, one cobas-positive cell pellet was deemed to be a false-positive result. The sensitivity of the cobas assay was 100% for pellet material and cell-free supernatant fluid, with specificities of 94.7% and 100%, respectively.

CONCLUSIONS

cobas hrHPV testing of HNSCC specimens demonstrated high concordance with p16 immunohistochemistry on the corresponding cell block and/or tissue specimen. Using the cell-free supernatant fluid in this platform could provide accurate HPV results while conserving material for cytomorphologic analyses.

Validation of the Applicability of In-Cell Fast Photochemical Oxidation of Proteins across Multiple Eukaryotic Cell Lines

Fast photochemical oxidation of proteins (FPOP), a hydroxyl radical-based protein footprinting method, coupled to mass spectrometry has been extensively used to study protein structure and protein-protein interactions in vitro. This method utilizes hydroxyl radicals to oxidatively modify solvent-accessible amino acids and has recently been demonstrated to modify proteins within live cells (IC-FPOP) and Caenorhabditis elegans. Here, we have expanded the application of IC-FPOP into a variety of commonly used cell lines to verify the applicability of the method across various cellular systems. IC-FPOP was able to successfully modify proteins in five different cell lines (Vero, HEK 293T, CHO, MCF-10A, and MCF-7). To increase the number of oxidatively modified proteins identified, we have also employed the use of offline high pH reversed-phase liquid chromatography (RPLC) followed by concatenation and online low-pH RPLC. The coupling of IC-FPOP to 2D-LC MS/MS resulted in a 1.7-fold increase in total identifications of oxidatively modified proteins, which expanded the dynamic range of the method. This work demonstrates the efficacy of using IC-FPOP to study protein-protein interactions in cells.

Protocol for Quantifying Zinc Flux in Cultured Cells using Fluorescent Indicators

Zinc (Zn²⁺) plays a vital role in the functioning of the cell. Cells have influx and efflux zinc transporters to regulate the levels of Zn²⁺ in the cytoplasm and organellar compartments to maintain homeostasis. We present a protocol to measure changes in cellular zinc concentrations using either a low-affinity membrane permeable or a high-affinity membrane impermeable fluorescent dye. Overall, zinc-specific fluorescent indicators using the assay can reliably detect the Zn²⁺ flux into or out of cultured cells.

For complete details on the use and execution of this protocol, please refer to Sanchez et al. (2019).

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Reliable measure of zinc flux into or out of cultured adherent cells

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Amenable for use with fluorescent dyes or genetically encoded zinc indicators

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Data and statistical analyses can be done using a standard spreadsheet

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Adaptable assay for other metal ions that bind specific fluorescent dyes

An image-based data-driven analysis of cellular architecture in a developing tissue

Quantitative microscopy is becoming increasingly crucial in efforts to disentangle the complexity of organogenesis, yet adoption of the potent new toolbox provided by modern data science has been slow, primarily because it is often not directly applicable to developmental imaging data. We tackle this issue with a newly developed algorithm that uses point cloud-based morphometry to unpack the rich information encoded in 3D image data into a straightforward numerical representation. This enabled us to employ data science tools, including machine learning, to analyze and integrate cell morphology, intracellular organization, gene expression and annotated contextual knowledge. We apply these techniques to construct and explore a quantitative atlas of cellular architecture for the zebrafish posterior lateral line primordium, an experimentally tractable model of complex self-organized organogenesis. In doing so, we are able to retrieve both previously established and novel biologically relevant patterns, demonstrating the potential of our data-driven approach.

Molecular markers for the classification of cytologically indeterminate thyroid nodules

BACKGROUND

The diagnosis of indeterminate lesions of the thyroid is a challenge in cytopathology practice. Indeed, up to 30% of cases lack the morphological features needed to provide definitive classification. Molecular tests have been developed to assist in the diagnosis of these indeterminate cases. The first studies dealing with the preoperative molecular evaluation of FNA samples focused on the analysis of BRAF^V600E or on the combined evaluation of two or three genetic alterations. The sensitivity of molecular testing was then improved through the introduction of gene panels, which became available for clinical use in the late 2000s. Two different categories of molecular tests have been developed, the 'rule-out' methods, which aim to reduce the avoidable treatment of benign nodules, and the 'rule-in' tests that have the purpose to optimize surgical management. The genetic evaluation of indeterminate thyroid nodules is predicted to improve patient care, particularly if molecular tests are used appropriately and with the awareness of their advantages and weaknesses. The main disadvantage of these tests is the cost, which makes them rarely used in Europe. To overcome this limitation, customized panels have been set up, which are able to detect the most frequent genetic alterations of thyroid cancer.

CONCLUSIONS

In the present review, the most recent available versions of commercial molecular tests and of custom, non-commercial panels are described. Their characteristics and accuracy in the differential diagnosis of indeterminate nodules, namely Bethesda classes III (Atypical follicular lesion of undetermined significance, AUS/FLUS) and IV (Suspicious for follicular neoplasm, FN/SFN) are fully analyzed and discussed.

Measuring Transcellular Interactions through Protein Aggregation in a Heterologous Cell System

Protein interactions at cellular interfaces dictate a multitude of biological outcomes ranging from tissue development and cancer progression to synapse formation and maintenance. Many of these fundamental interactions occur in trans and are typically induced by heterophilic or homophilic interactions between cells expressing membrane anchored binding pairs. Elucidating how disease relevant mutations disrupt these fundamental protein interactions can provide insight into a myriad of cell biology fields. Many protein-protein interaction assays do not typically disambiguate between cis and trans interactions, which potentially leads to an overestimation of the extent of binding that is occurring in vivo and involve labor intensive purification of protein and/or specialized monitoring equipment. Here, we present an optimized simple protocol that allows for the observation and quantification of only trans interactions without the need for lengthy protein purifications or specialized equipment. The HEK cell aggregation assay involves the mixing of two independent populations of HEK cells, each expressing membrane-bound cognate ligands. After a short incubation period, samples are imaged and the resulting aggregates are quantified.

Biosafety in the preparation and processing of cytology specimens with potential coronavirus (COVID-19) infection: Perspectives from Taiwan

This commentary focuses on the cytopathology laboratory, the authors' experiences with coronavirus (COVID‐19) in Taiwan, and current guidelines on COVID‐19 infection prevention and control. The objective of this report is to provide cytopathology professionals a timely, in‐depth, evidence‐based review of biosafety practices for those at risk for coronavirus (COVID‐19) infection.

Acid-Switchable DNAzyme Nanodevice for Imaging Multiple Metal Ions in Living Cells

Metal-assisted deoxyribozyme catalysis (DNAzyme) has been a general platform for constructing highly sensitive and selective detection sensors of metal ions. However, the "always on" mode of the traditional DNAzyme sensors greatly limits their application in the visual analysis of endogenous metal ions in a complex physiological microenvironment. To overcome this obstacle, a smart acid-switchable DNAzyme nanodevice is designed to control the DNAzyme activity in living cells and achieve simultaneous visualization of metal ions (Zn²⁺ and Pb²⁺) in situ. This nanodevice is built on DNAzyme precursors (DPs) and acid-switchable DNA (SW-DNA), precisely responding to pH variations in the range of 4.5-7.0, and the state of the three-strand hybridization of DPs successfully renders the DNAzymes inactive before being transported into cells. Once the nanodevice is taken up into living cells, the SW-DNA will change the configuration from linear to triplex in the acidic intracellular compartments (lysosomes, pH ∼4.5 to 5.0) and then the strands hybridized with the SW-DNA are liberated and subsequently react with DPs to form the active DNAzyme, which can further realize multi-imaging of intracellular metal ions. Moreover, this strategy has broad prospects as a powerful platform for constructing various acid-switchable nanodevices for visual analysis of multiple biomolecules in living cells.

The Antibody-Free Recognition of Cancer Cells Using Plasmonic Biosensor Platforms with the Anisotropic Resonant Metasurfaces

It is vital and promising for portable and disposable biosensing devices to achieve on-site detection and analysis of cancer cells. Although traditional labeling techniques provide an accurate quantitative measurement, the complicated cell staining and high-cost measurements limit their further development. Here, we demonstrate a nonimmune biosensing technology. The plasmonic biosensors, which are based on anisotropic resonant split ring resonators in the terahertz range, successfully realize the antibody-free recognition of cancer cells. The dependences of Δf and the fitted phase slope on the cancer cell concentration at different polarizations give new perspective in hexagonal radar maps. The results indicate that the lung cancer cell A549 and liver cancer cell HepG2 can be distinguished and determined simply based on the enclosed shapes in the radar maps without any antibody introduction. The minimum concentration of identification reduces to as low as 1 × 10⁴ cells/mL and such identification can be kept valid in a wide range of cell concentration, ranging from 10⁴ to 10⁵. The construction of two-dimensional extinction intensity cards of corresponding cancer cells based on the wavelet transform method also supplies corresponding information for the antibody-free recognition and determination of two cancer cells. Our plasmonic metasurface biosensors show a great potential in the determination and recognition of label-free cancer cells, being an alternative to nonimmune biosensing technology.

Practical adoption of state-of-the-art hiPSC-cardiomyocyte differentiation techniques

Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes are a valuable resource for cardiac therapeutic development; however, generation of these cells in large numbers and high purity is a limitation in widespread adoption. Here, design of experiments (DOE) is used to investigate the cardiac differentiation space of three hiPSC lines when varying CHIR99027 concentration and cell seeding density, and a novel image analysis is developed to evaluate plate coverage when initiating differentiation. Metabolic selection via lactate purifies hiPSC-cardiomyocyte populations, and the bioenergetic phenotype and engineered tissue mechanics of purified and unpurified hiPSC-cardiomyocytes are compared. Findings demonstrate that when initiating differentiation one day after hiPSC plating, low (3 μM) Chiron and 72 x 10³ cells/cm² seeding density result in peak cardiac purity (50–90%) for all three hiPSC lines. Our results confirm that metabolic selection with lactate shifts hiPSC-cardiomyocyte metabolism towards oxidative phosphorylation, but this more “mature” metabolic phenotype does not by itself result in a more mature contractile phenotype in engineered cardiac tissues at one week of culture in 3D tissues. This study provides widely adaptable methods including novel image analysis code and parameters for refining hiPSC-cardiomyocyte differentiation and describes the practical implications of metabolic selection of cardiomyocytes for downstream tissue engineering applications.

A comparative analysis of methods to measure kinetochore-microtubule attachment stability

During mitosis, spindle microtubules dynamically attach to and detach from kinetochores in a precise and regulated fashion. To ensure mitotic fidelity, kinetochore-microtubule (k-MT) attachments must be stable enough to satisfy the spindle assembly checkpoint (SAC), but sufficiently unstable to facilitate the correction of maloriented attachments. Different methods are available to assess k-MT stability in both live and fixed cells, but a comparative survey of these methods has not yet been reported. Here, we evaluate several quantitative and semiquantitative methods for determining k-MT stability and apply each technique to illustrate changes in spindle microtubule dynamics upon perturbation with physiologically relevant concentrations of microtubule stabilizing (Taxol) and destabilizing (UMK57 and nocodazole) compounds. We discuss the utility of each technique for defining specific features of spindle microtubule dynamics and k-MT attachment stability.

Human Pluripotent Stem Cells in Reproductive Science-a Comparison of Protocols Used to Generate and Define Male Germ Cells from Pluripotent Stem Cells

Globally, fertility-related issues affect around 15% of couples. In 20%–30% of cases men are solely responsible, and they contribute in around 50% of all cases. Hence, understanding of in vivo germ-cell specification and exploring different angles of fertility preservation and infertility intervention are considered hot topics nowadays, with special focus on the use of human pluripotent stem cells (hPSCs) as a source of in vitro germ-cell generation. However, the generation of male germ cells from hPSCs can currently be considered challenging, making a judgment on the real perspective of these innovative approaches difficult. Ever since the first spontaneous germ-cell differentiation studies, using human embryonic stem cells, various strategies, including specific co-cultures, gene over-expression, and addition of growth factors, have been applied for human germ-cell derivation. In line with the variety of differentiation methods, the outcomes have ranged from early and migratory primordial germ cells up to post-meiotic spermatids. This variety of culture approaches and cell lines makes comparisons between protocols difficult. Considering the diverse strategies and outcomes, we aim in this mini-review to summarize the literature regarding in vitro derivation of human male germ cells from hPSCs, while keeping a particular focus on the culture methods, growth factors, and cell lines used.