The development of perianal fistulas leads to a significant decrease in the quality of patients’ lives. The onset of this condition is dependent on many factors, including inflammation or trauma. In the occurrence of Crohn’s disease-associated fistulas, numerous molecular factors and metabolic pathways are involved. To integrate the current knowledge on the biochemical, genetic, and epigenetic factors taking part in the development of perianal fistulas, we conducted a literature review. We gathered and analyzed 45 articles on this subject. The pathophysiology of fistulas associated with Crohn’s disease (CD) involves epithelial–mesenchymal transition (EMT) and matrix remodeling enzymes, with key regulators including transforming growth factor β (TGF-β), tumor necrosis factor α (TNFα), and interleukin-13 (IL-13). Genetic factors, such as mutations in receptor-interacting serine/threonine-protein kinase 1 (RIPK1), interleukin-10 receptor (IL-10R), and the MEFV gene, contribute to the onset and severity of perianal fistulas, suggesting potential therapeutic targets. Understanding the complex interplay of molecular pathways and genetic predispositions offers insights into personalized treatment strategies for this challenging condition. Further research is necessary to elucidate the intricate mechanisms underlying the pathogenesis of perianal fistulas and to identify new therapeutic interventions.

Background: The oculomotor nerve (CN III) traverses several anatomically complex regions, including the interpeduncular cistern, cavernous sinus, superior orbital fissure, and orbit, where its relationships with adjacent neurovascular structures are of considerable clinical relevance. Although numerous anatomical studies have described individual segments of CN III, the available evidence remains fragmented. This systematic review aimed to synthesize the published literature on the origin, course, branching pattern, morphometry, and anatomical variations of the oculomotor nerve, with emphasis on clinically relevant relationships. Methods: A systematic search of PubMed, Embase, Web of Science, and Google Scholar was performed for original human studies on oculomotor nerve anatomy published up to September 2025. Two reviewers independently screened records. Eligible studies were assessed using the AQUA tool. Extracted data included nerve segment, course, branching, morphometry, anatomical relationships, and reported variations. Owing to methodological heterogeneity, the findings were synthesized qualitatively. Results: Thirty-five original studies were included in the systematic review. They used heterogeneous units of analysis, including living participants, cadavers, heads, brains, orbits, nerves, and histological specimens; therefore, aggregate sample size was not calculated. Cadaveric dissection and MRI were the most common methods of CN III presentation. The orbital segment was the best-described portion of the nerve and demonstrated the greatest branching variability, particularly within the superior and inferior divisions. The cisternal segment showed clinically important relationships with the posterior cerebral, superior cerebellar, and posterior communicating arteries, supporting the anatomical basis of neurovascular compression and oculomotor palsy. Morphometric comparisons across studies were limited by differences in methods, landmarks, and tissue preparation. Conclusions: The oculomotor nerve demonstrates segment-specific anatomical variability, with the greatest complexity in its orbital branching pattern and important neurovascular relationships along its cisternal and cavernous course. This knowledge may be of value to microsurgical, orbital, and neuroradiological practice. The evidence remains limited by methodological heterogeneity, underreporting of sex- and population-based differences, and the small number of studies addressing the intramesencephalic segment.

The development of perianal fistulas leads to significant decrease in the quality of patients’ lives. The onset of this condition is dependent on many factors, including inflammation or trauma. In the occurrence of Crohn’s Disease-associated fistulas, numerous molecular factors and metabolic pathways are involved. To integrate the current knowledge on the biochemical, genetic, and epigenetic factors taking part in the development of perianal fistulas, we conducted a literature review. We gathered and analyzed 39 articles on this subject. The pathophysiology of fistulas associated with Crohn’s disease (CD) involves epithelial-mesenchymal transition (EMT) and matrix remodeling enzymes, with key regulators including transforming growth factor β (TGF-β), tumor necrosis factor α (TNFα), and interleukin-13 (IL-13). Genetic factors, such as mutations in receptor-interacting serine/threonine-protein kinase 1 (RIPK1), interleukin-10 receptor (IL-10R), and the MEFV gene, contribute to the onset and severity of perianal fistulas, suggesting potential therapeutic targets. Understanding the complex interplay of molecular pathways and genetic predispositions offers insights into personalized treatment strategies for this challenging condition. Further research is necessary to elucidate the intricate mechanisms underlying the pathogenesis of perianal fistulas and to identify new therapeutic interventions.

Aqueous formaldehyde (FA) solution, known as formalin, is currently the primary agent used for preserving tissue samples and anatomical specimens. Formaldehyde is widely used in laboratories and the chemical industry; it also occurs as an air pollutant and endogenous cellular metabolite. The potential carcinogenic effects of formalin on the respiratory tract are well documented. A less recognized consequence of occupational exposure to FA is its detrimental effect on the central nervous system (CNS) and brain function. A literature review was conducted to investigate the effects of FA on the brain. Five databases were searched: PubMed, Web of Science (WoS), Embase, ScienceDirect, and Google Scholar. To describe the effects of FA exposure and endogenous FA generation, 35 relevant publications were collected and analyzed. The literature review demonstrated that inhalation is the most common route of FA exposure. Several studies have shown that FA may cause hippocampal damage, disrupt melatonin secretion, and induce a wide range of cognitive disorders with varying characteristics and severity. These disorders include memory impairment, disturbances in balance and spatial orientation, learning difficulties, sleep disturbances, impaired judgment, and prolonged reaction times to stimuli. Increased endogenous FA concentration has also been associated with a higher risk of neurodegenerative diseases, such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis. The literature analysis demonstrated the high neurotoxicity of FA, which may lead to numerous neuropsychiatric disorders. We aim to draw attention to the risks associated with the routine use of formalin, particularly among anatomists and pathologists, and to encourage consideration of less harmful alternative preservation agents.