Imaging technologies have played a pivotal role in advancing biological research by enabling visualization of biological structures and processes. While traditional electron microscopy (EM) produces two-dimensional images, emerging techniques now allow high-resolution three-dimensional (3D) characterization of specimens in situ, meeting growing needs in molecular and cellular biology. Combining transmission electron microscopy (TEM) with serial sectioning inaugurated 3D imaging, attracting biologists seeking to explore cell ultrastructure and driving advancement of 3D EM reconstruction. By comprehensively and precisely rendering internal structure and distribution, 3D TEM reconstruction provides unparalleled ultrastructural insights into cells and molecules, holding tremendous value for elucidating structure-function relationships and broadly propelling structural biology. Here, we first introduce the principle of 3D reconstruction of cells and tissues by classical approaches in TEM and then discuss modern technologies utilizing TEM and on new SEM-based as well as cryo-electron microscope (cryo-EM) techniques. 3D reconstruction techniques from serial sections, electron tomography (ET), and the recent single-particle analysis (SPA) are examined; the focused ion beam scanning electron microscopy (FIB-SEM), the serial block-face scanning electron microscopy (SBF-SEM), and automatic tape-collecting lathe ultramicrotome (ATUM-SEM) for 3D reconstruction of large volumes are discussed. Finally, we review the challenges and development prospects of these technologies in life science. It aims to provide an informative reference for biological researchers.

The adverse effects of microplastics (MP) found in food on the health have recently been recognized as a new source of human health risks. In order to evaluate and minimize them, it is necessary to evaluate the exposure using sensitive and specific methods. The aim of the research was the substantiation of methodological approaches to the identification and quantification of microplastics in food based on the analysis of literature data. Material and methods. Literature selection was carried out using the PubMed international reference database for the period from 2014 to 2023 using keywords corresponding to the context of the research theme. A total of 159 sources were selected, of which 94 original and review papers were included in the review according to the criteria of their relevance to the problem under consideration, scientific reliability and completeness. Results. At present, various approaches have been developed that make it possible to isolate MPs from complex bioorganic matrices (such as, for example, seafood), classify them by chemical composition, and quantify their content through the mass or number of particles. Among the most developed physic-chemical methods for the analysis of MPs are Fourier transform IR spectrometry and Raman microspectrometry, pyrolysis gas chromatography - mass spectrometry, thermogravimetric analysis, as well as approaches based on liquid chromatography, microfluorimetry, analytical scanning and transmission electron microscopy and others. Unsolved problems in the field of MP research in food include the high laboriousness and low performance of the identification technologies used, the lack of reference and standard samples of MP, the complexity of the equipment used, which makes it difficult to use it for routine hygienic control. The issue of the influence of MP aging degree on the results of its qualitative and quantitative determination has not been sufficiently studied. Some hopes in the field of development of rapid analysis of MTs are pinned on the use of aptamers. Conclusion. Existing analytical methods make it possible to determine the content of MPs in environmental objects, but further improvement and validation of these methods is required in relation to the assessment of the content of MPs in various types of food.

BACKGROUND: Crescentic glomerulonephritis with syphilis infection is rare, and the mechanism underlying the formation of glomerular capillary wall damage-induced crescent has not been elucidated.
METHODS: A 62-year-old Japanese male showed edema, eruption, and rapid deterioration of the renal function after an acute syphilis infection. A renal biopsy showed crescentic glomerulonephritis with C3 deposition in the glomerular capillary wall, and immunostaining for anti-Treponema pallidum antibody was weakly positive in some interstitium and one glomerulus. Electron microscopy revealed the presence of string-shaped structures in the glomerular capillary walls. After treatment with penicillin followed by prednisolone, the renal function and urinary abnormalities, including Treponema pallidum protein, disappeared.
CONCLUSIONS: Crescentic glomerulonephritis associated with syphilis showed a string-shaped deposition in the glomerular capillary and urinary Treponema pallidum protein excretion, and was effectively treated with penicillin and prednisolone.

BACKGROUND: Asbestos is a mineral present in nature and it has been used for years in numerous settings. Asbestos enters the bloodstream and lymphatic system mainly through breathing.
OBJECTIVE: Studies with asbestos fiber\'s quantification in human tissues are scarce except for the lung. This article summarizes asbestos studies in some extra-abdominal tissues.
METHODS: A scoping review of articles that quantified asbestos fibers in extra-abdominal tissues (lymph nodes, pharynx, larynx, trachea, heart) by electron microscopy (Scanning-SEM or Transmission-TEM) was performed.
RESULTS: The 10 studies selected comprised 52 cases, out of whom 108 samples were analyzed. Mostly samples were lymph node tissues (102), followed by larynx (3) and myocardium (3). No studies were found that determined the presence of asbestos in the pharynx or trachea. The concentration of asbestos fibers detected in the lymph nodes was from 0.003 million fibers per gram of dry tissue (mfgdt) up to 7400 mfgdt, in the larynx the range was from 0.5 mfgdt up to 3.6 mfgdt, in myocardium no asbestos fibers were detected.
CONCLUSIONS: The studies included were heterogeneous in terms of case and sample characteristics and analytical techniques. As subjects exposed to asbestos are often positive for fibers in thoracic lymph nodes, we suggest that whenever a human tissue sample is analyzed for asbestos presence, the relevant draining lymph node should be concomitantly studied.

Fibrillary glomerulonephritis (FGN) is a rare immune-mediated glomerular disease traditionally characterized by the presence of amyloid-like, randomly aligned, fibrillary deposits in the capillary wall, measuring approximately 20 nm in diameter and composed of polyclonal IgG. FGN is usually a primary disease with no pathognomonic clinical or laboratory findings. More than that, on light microscopic evaluation, it can receive various histological patterns, rendering its diagnosis indistinguishable. However, the identification by immunohistochemistry of a novel biomarker, DNA-J heat-shock protein family member B9 (DNAJB9), has created a new era in FGN diagnosis even in the absence of electron microscopy. Typically, most patients manifest various degrees of renal insufficiency, hypertension, microscopic hematuria, proteinuria, and occasionally frank nephrotic syndrome. The prognosis is usually severe and progression to end-stage kidney disease (ESKD) is the rule, given that no specific treatment is available until now, despite the fact that in small studies rituximab-based therapy seems to alleviate the severity and improve the disease progression. Herein, we report the case of a 63-year-old Caucasian man presenting with uncontrolled hypertension, headache, shortness of breath, and lower limb edema. Diagnostic evaluation revealed mild deterioration of kidney function, nephrotic range proteinuria, and faint IgGκ monoclonal bands in serum and urine immunofixation. After negative meticulous investigation for secondary nephrotic syndrome causes, the patient underwent a kidney biopsy. Biopsy sample showed two glomeruli with mesangial expansion and thickened glomerular basement membrane (GBM) on light microscopy, a pattern masquerading as membranous nephropathy stage III-IV, while IgG and C3 were 1-2+ on GBM and mesangium in immunofluorescence. Thickened GBM with fibrils on electron microscopy were found, while DNAJB9 in immunohistochemistry was positive, confirming FGN. Once diagnosis of FGN was made, a combination of steroids with rituximab was initiated while the patient was receiving the standard anti-hypertensive therapy, simultaneously with a sodium-glucose cotransporter-2 (SGLT2) inhibitor. The 12-month follow-up showed approximately 85% decrease in proteinuria alongside stabilization of kidney function and blood pressure normalization. Hence, in this article, we aim to highlight that DNAJB9-associated FGN may mimic membranous glomerulopathy stage III-IV on light microscopy, especially when a small kidney sample with extensive involvement by fibrils of GBM is examined. Moreover, we underscore the fact that ultramicroscopic examination is of crucial importance in the differential diagnosis of glomerular deposition diseases and that DNAJB9 identification on immunohistochemistry consists of a revolutionary and robust biomarker in FGN diagnosis.

Invasive ductal carcinoma of no special type is the most common type of breast cancer. In light of the above, many authors have reported the histological and electron microscopic characteristics of these tumors. On the other hand, a limited number of works exist where the authors have concentrated on investigating the extracellular matrix. This article presents data received as the results of light and electron microscopic examination of the extracellular matrix, angiogenesis, and cellular microenvironment of invasive breast ductal carcinoma of no special type. The authors have shown that the processes of stroma formation in the IDC NOS type are associated with the presence of fibroblasts, macrophages, dendritic cells, lymphocytes, and other cells. It was also shown the detailed interaction of the above cells with each other, as well as with vessels and fibrillar proteins such as collagen and elastin. The microcirculatory component is characterized by histophysiological heterogeneity, which manifests as the activation of angiogenesis, relative vascular differentiation, and regression of individual microcirculation components.

Pituitary neuroendocrine tumors (PitNETs) lacking lineage affiliation are termed \"null cell\" PitNETs (NCTs). NCTs are characterized as being immunonegative for pituitary hormones as well as transcription factors. We analyzed the ultrastructure and immunohistochemistry of six hormone-negative and transcription factor (TPIT, PIT1, SF1)-negative PitNETs, with less than 1% immunoreactive cells. Histologically, three cases presented a perivascular pattern and pseudorosettes; the other three showed a solid pattern with oncocytic changes. Electron microscopic examination revealed poorly differentiated tumor cells with sparsely scattered secretory granules and intracellular organelles in all null cell tumors when compared with hormone-positive PitNETs. Two cases harbored a honeycomb Golgi (HG) structure, and three oncocytic tumors showed mitochondrial accumulation. The two HG cases were immunopositive for newly obtained TPIT (CL6251) and showed some adrenocorticotropic hormone-positive cells, while the remaining four were diffusely immunopositive for GATA3, with two SF1-positive cases identified in subsequent immunostaining. Thus, these six cases may be classified as two sparsely granulated corticotroph PitNETs, two gonadotroph PitNETs with SF1 re-staining, and two likely gonadotroph PitNETs with GATA3 immunostaining. No \"true NCT\" was detected among 1071 PitNETs, demonstrating the importance of precise diagnosis following the most recent criteria to improve therapeutic success.

C3 glomerulopathy (C3G) is a rare disease resulting from dysregulation of the alternative complement pathway, resulting in the deposition of complement component 3 (C3) in the kidney. It encompasses two major subgroups: dense deposit disease and C3 glomerulonephritis (C3GN). Although the alternative complement pathway is typically a very tightly controlled system, dysregulation can be a result of genetic mutations in the fluid phase or membrane-bound inhibitors or accelerators. In addition, de novo/acquired autoantibodies against any of the regulatory proteins can alter complement activation either by negating an inhibitor or activating an accelerator. Triggering events can be complex; however, the final pathway is characterized by the uncontrolled deposition of C3 in glomeruli and the formation of the membrane attack complex. Light microscopic findings can be quite heterogeneous with a membranoproliferative pattern most commonly encountered. Diagnostic confirmation of C3G is based on a characteristic pattern of glomerular immunofluorescence staining, with C3-dominant deposits that are at least 2 orders of intensity greater than staining for any immunoglobulin (Ig) or C1q. Electron microscopy is necessary for diagnosing DDD in particular, but can also help to distinguish C3GN from other glomerular disease mimickers.

Crystal-storing histiocytosis (CSH) is a rare disorder characterized by the accumulation of non-neoplastic histiocytes that contain intracytoplasmic crystallized immunoglobulins. Although CSH can occur in various organs, gastric CSH is very rare. Therefore, diagnosing gastric CSH remains a challenge. Here, we present the case of a 69-year-old man with localized gastric CSH who presented with positive fecal occult blood for 2 days. Gastroscopy showed that there was a piece of irregular whitish focus in the big bend of the gastric antrum, which was soft and elastic. Histologically, the biopsied gastric mucosa showed chronic inflammation, mild activity with erosion, and numerous eosinophilic mononuclear cells containing fibrillary crystalloid inclusions in the lamina propria. Immunohistochemically, these crystal-containing cells were positive for CD68/PGM1 and Igk, which revealed that the cells were histiocytes harboring kappa light chain-restricted immunoglobulin crystals. Electron microscopic examination showed numerous high-electron-density particles in the cytoplasm of cells, with crystal structures of different sizes and shapes. This case highlights how immunohistochemistry can help with differential diagnosis and classification.

Peritoneal tissue is the second most affected site by malignant mesothelioma linked to asbestos exposure. This scoping review aims to summarize the findings of the studies in which asbestos fibers in the peritoneum were quantified by electron microscopy, occasionally associated with spectroscopy, both in neoplastic and non-neoplastic tissue. The 9 studies selected comprised 62 cases, out of whom 100 samples were analyzed. Asbestos fibers were detected in 58 samples (58%). In addition, 28 cases had diagnosis of peritoneal mesothelioma. For 32 cases, a lung tumor sample was available: 28/32 samples analyzed presented asbestos fibers; 18/32 reported amphiboles with a range from not detected to 14.2 million fibers per gram of dry tissue (mfgdt); 18/32 reported chrysotile, with a range of 0 to 90 mfgdt. The studies were heterogeneous for type of samples, analytical technology, and circumstances of exposure to asbestos. To evaluate asbestos fibers in the peritoneum and to better understand the association between asbestos exposure and malignant peritoneal mesothelioma, it is desirable that the search for asbestos fibers becomes a routine process every time peritoneal tissue is accessible.