A New Paradigm for Tissue Diagnostics: Tools and Techniques to Standardize Tissue Collection, Transport, and Fixation

Efficacy of imaging techniques for the diagnosis of apical periodontitis: A systematic review

BACKGROUND

Apical periodontitis (AP) is a chronic inflammatory response of microbial aetiology. Pathological changes associated with AP may not be visible on radiographic images and may linger without causing any symptoms. Clinicians rely mostly on clinical examination and imaging techniques to establish a diagnosis.

OBJECTIVES

The aim of this review was to answer the following question using the PICO format: In the adult human permanent dentition (P), what is the efficacy of diagnostic imaging of the periapical tissues (I) using histopathology as a reference standard (C) in the diagnosis of apical periodontitis, in terms of diagnostic accuracy (O).

METHODS

MEDLINE, EMBASE, Scopus and Cochrane Library were searched for English articles published through October 2021. At least two independent reviewers evaluated the study design, imaging modality used, histopathological assessment, outcome measures, results and conclusions for each article. The risk of bias was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2.

RESULTS

The initial search strategy identified 544 articles. Seven articles were included for analysis in the final review, all of which involved tissue samples obtained from cadavers. No clinical studies were identified that met the eligibility criteria. A consistently low sensitivity score and negative predictive value were reported for periapical radiography, especially in comparison to CBCT, which scored highly. Both modalities achieved high scores for specificity and positive predictive value. Diagnostic accuracy of CBCT was lower for root-filled teeth in comparison to non-root-filled teeth.

DISCUSSION

Assessment of the periapical tissues using periapical radiographs was shown to have a low to moderate agreement with the histopathological assessment. CBCT was reported to be more accurate than PR and demonstrated a good agreement with histopathology, especially for non-root-filled teeth.

CONCLUSIONS

This review identified a need for greater standardization in methodology and reporting, and as the findings are based on cadaver studies, their clinical relevance must be interpreted with caution.

REGISTRATION

PROSPERO (CRD42021272147).

Construction of hematoxylin-eosin, immunohistochemistry, and EBER-ISH methodology after trichloroisocyanuric acid treatment in melanin-containing tissues

This study investigated the effects of trichloroisocyanuric acid (TCCA) on the bleaching and morphology of melanin-containing pathological sections. The pathological sections of 27 patients with high melanin content were bleached with 0.5% potassium permanganate, 10% hydrogen peroxide, and different concentrations of TCCA. Significant differences were found among the blank control group, 1% TCCA group (P < 0.0001). The hematoxylin-eosin (HE) score of the "recovery pH" HE staining group after treatment with 1% TCCA was similar to that of the "Conventional HE" scheme group (P > 0.05). The morphological diagnostic scores of 50 cases of pathological sections with different melanin content before and after TCCA bleaching were compared. The results showed a significant difference in the diagnostic score between the middle- and high-melanin content groups before and after 1% TCCA bleaching (P < 0.05). Immunohistochemical staining was performed on meningeal melanoma tissue. For this, 8% TCCA solution was used to remove melanin after Ki67, S100, and β-catenin immunohistochemical staining. After bleaching with TCCA, the staining and positioning of each marker with different localization were accurate and the background was clear. The same results were also shown with EBER-ISH. This study concluded that 1% TCCA could be used for HE staining of pathological sections containing melanin, and "restore pH" HE scheme as the staining method after TCCA melanin removal. Further, 8% TCCA was used for bleaching after immunohistochemical DAB staining. Melanin can be completely removed, and sections can meet diagnostic needs.

Quality Control of Breast Cancer Surgery Samples: Introducing Time Stamp Checking

Background: Analytical information obtained from clinical tissue samples has recently become more important due to recent advancements in the clinical practice of medicine, for example, gene panel testing. However, acquiring and managing the sample quality, which greatly influences the analyses, are not sufficient and hence requires immediate attention. We introduced time stamp (TS) recording and documentation using the Standard PREanalytical Code (SPREC) for breast cancer surgery samples to monitor and control their quality. Materials and Methods: The TS recording used SPREC for quality control of each sample by recording seven factors: type of sample, type of collection, warm ischemia time (WIT), cold ischemia time (CIT), fixation type, fixation time (FT), and long-term storage. The responsibilities to record each factor were assigned among group members (breast surgeons, anesthesiologists, pathologists, operating room nurses, and medical technologists in pathology). Results: Records based on SPREC were recorded for 393 surgical cases of first-time breast cancer patients performed at the Kanagawa Cancer Center from May 2018 to April 2019. The vascular clamp time was defined as when skin flap formation was completed, regardless of the surgical procedure. An anesthesiologist recorded the vascular clamp time and sample collection time, and the pathologist recorded the fixation start time and fixation end time. WIT was 23 (3-116) minutes (breast-conserving surgery, 11 [3-38] minutes; mastectomy, 26 [5-116] minutes; and nipple-sparing mastectomy, 39 [31-43] minutes), CIT was 37 (3-1052) minutes, and FT was 43 (17-115) hours. The median CIT and FT were significantly shortened after introducing the TS system, and the variabilities were reduced. Conclusion: A TS system for quality control of breast cancer surgical sample functions well due to the establishment of highly versatile WIT and a working group consisting of multiple members of different occupations who shared roles.

Spatially Resolved Analytical Chemistry in Intact, Living Tissues

Tissues are an exciting frontier for bioanalytical chemistry, one in which spatial distribution is just as important as total content. Intact tissue preserves the native cellular and molecular organization and the cell-cell contacts found in vivo. Live tissue, in particular, offers the potential to analyze dynamic events in a spatially resolved manner, leading to fundamental biological insights and translational discoveries. In this Perspective, we provide a tutorial on the four fundamental challenges for the bioanalytical chemist working in living tissue samples as well as best practices for mitigating them. The challenges include (i) the complexity of the sample matrix, which contributes myriad interfering species and causes nonspecific binding of reagents; (ii) hindered delivery and mixing; (iii) the need to maintain physiological conditions; and (iv) tissue reactivity. This framework is relevant to a variety of methods for spatially resolved chemical analysis, including optical imaging, inserted sensors and probes such as electrodes, and surface analyses such as sensing arrays. The discussion focuses primarily on ex vivo tissues, though many considerations are relevant in vivo as well. Our goal is to convey the exciting potential of analytical chemistry to contribute to understanding the functions of live, intact tissues.

Effect of immediate cold formalin fixation on phosphoprotein IHC tumor biomarker signal in liver tumors using a cold transport device

Phosphoproteins are the key indicators of signaling network pathway activation. Many disease treatment therapies are designed to inhibit these pathways and effective diagnostics are required to evaluate the efficacy of these treatments. Phosphoprotein IHC have been impractical for diagnostics due to inconsistent results occurring from technical limitations. We have designed and tested a novel cold transport device and rapid cold plus warm formalin fixation protocol using phosphoproteins IHC. We collected 50 liver tumors that were split into two experimental conditions: 2 + 2 rapid fixation (2 hours cold then 2 hour warm formalin) or 4 hour room-temperature formalin. We analyzed primary hepatocellular carcinoma (n = 10) and metastatic gastrointestinal tumors (n = 28) for phosphoprotein IHC markers pAKT, pERK, pSRC, pSTAT3, and pSMAD2 and compared them to slides obtained from the clinical blocks. Expression of pERK and pSRC, present in the metastatic colorectal carcinoma, were better preserved with the rapid processing protocol while pSTAT3 expression was detected in hepatocellular carcinoma. Differences in pSMAD2 expression were difficult to detect due to the ubiquitous nature of protein expression. There were only 3 cases expressing pAKT and all exhibited a dramatic loss of signal for the standard clinical workflow. The rapid cold preservation shows improvement in phosphoprotein preservation.