Perianal fistulas can result in notable morbidity and reduced quality of life for those affected, most often men 30 to 40 years old. A thorough understanding of a patient's fistula anatomy is crucial in determining appropriate treatment; MRI is highly effective in providing this information. Additionally, MRI can be used following treatment to determine success or failure and aid with potential next steps. This article provides a comprehensive review of the MRI appearance of perianal fistulas before and after treatment, with emphasis on imaging features that support accurate characterization and guide optimal clinical management.

High-resolution pelvic MR imaging is central to the diagnosis, staging, treatment planning, and posttreatment assessment of anal squamous cell carcinoma (SCCA), the most common malignancy of the anal canal. Accurate imaging interpretation requires detailed knowledge of anal canal anatomy, lymphatic drainage, and optimized MR imaging technique. MR imaging provides excellent evaluation of primary tumor extent, while nodal and distant staging are enhanced by computed tomography (CT) and FDG-PET/CT. Imaging directly informs contemporary chemoradiation strategies and surveillance. Human papillomavirus (HPV) is implicated in nearly 90% of SCCA, is vaccine-preventable, and HPV ctDNA shows promise for response assessment and relapse prediction.

This review highlights the MR imaging appearance of benign colonic and anorectal conditions, emphasizing anatomic landmarks and characteristic imaging patterns. MR imaging enables confident differentiation of benign neoplasms, cystic lesions, and inflammatory processes through excellent soft-tissue contrast, multiplanar capability, and advanced sequences such as diffusion-weighted imaging. As a radiation-free modality with high diagnostic performance, MR imaging plays an increasingly important role in evaluating colorectal pathology, particularly in pregnancy and in patients requiring avoidance of ionizing radiation.

Ulcerative colitis (UC) is an intestinal inflammatory disorder primarily driven by M1 macrophage activation and oxidative stress. p62/Sequestosome-1, a multifunctional autophagy adaptor protein, plays a critical role in regulating autophagy and inflammation. α-Methylene-γ-butyrolactone (αMγB), a conserved structural motif found in anti-inflammatory sesquiterpene lactones from traditional medicinal herbs, was shown to suppress M1 macrophage activation and inflammation. This study aimed to investigate the role of p62 in UC pathogenesis and evaluate the therapeutic potential of αMγB. We found that genetic deletion of p62 aggravated disease severity in both acute pneumonia and UC mouse models. Treatment with αMγB alleviated UC symptoms by reprogramming macrophage polarization, reshaping the mucosal immune microenvironment, and suppressing inflammatory crosstalk between macrophages and epithelial cells. Mechanistically, αMγB covalently modified p62 at C291, preventing its ubiquitination and stabilizing it, which enhanced Keap1 binding and drove its autolysosomal degradation. This process released Nrf2, facilitated its nuclear translocation, and activated the expression of downstream antioxidant and anti-inflammatory genes. Importantly, αMγB established a positive feedback loop between Nrf2 and p62 that sustained p62 upregulation and further promoted Keap1 autolysosomal degradation. These protective effects were abolished in p62 (C291S) mutant mice or upon Nrf2 inhibition. Collectively, our findings demonstrated that αMγB ameliorated UC by specifically targeting p62 at C291, promoting its stabilization, and enhancing Keap1 degradation, thereby modulating macrophage polarization. These findings highlighted the therapeutic potential of αMγB and suggested that augmenting p62 function might represent a promising strategy for UC treatment.

This study presents 2 cases of wound myiasis in a dog and a cat involving morphological and molecular identification in Korea. A 7-year-old male Jindo mix dog, Canis familiaris, was admitted to a veterinary clinic in Yangsan-si, Gyeongsangnam-do, Korea, in July 2024. The bite wound near the right rib was infected with maggots. We carefully removed the 5 maggots using forceps. The wound healed without any subsequent complications. A Korean Shorthair stray cat, Felis catus, was brought to the same clinic in October 2024 after being hit by a car. The maggot-infected wounds were found in the anus and perianal regions. We removed all 10 maggots from the wounds. After treatment, no living maggots were observed; however, the cat was euthanized due to trauma-related complications. The maggots from the dog and the cat were third instars with 12 body segments and posterior spiracles containing 3 distinct slits. Compared with the dog-derived larvae, the cat-derived larvae had a more dorsally positioned posterior process of the mouth hook, reduced dorsal papillae distances, and distinctly sclerotized ventral cornua. Complete cox1 gene analysis confirmed the dog- and cat-derived larvae as Lucilia sericata (Meigen, 1826) and Lucilia illustris (Meigen, 1826), respectively, whereas 18S rRNA gene analysis showed limited species-level resolution. In the present study, wound myiasis caused by L. sericata and L. illustris is described in a dog and a cat in Korea based on morphological and molecular findings.

Background and objectivesBenign anorectal diseases are prevalent in the general population. Currently, spinal anesthesia is mainly performed in the lateral and sitting positions and is rarely performed in the prone or jackknife positions. This study compared the effects of the prone, lateral, and sitting positions on sensory and motor blocks in patients undergoing anorectal surgery under spinal anesthesia.Materials and methodsIn this prospective comparative study, 75 ASA I and II class patients aged >18 years who underwent anorectal surgery were included, with 25 patients in each group. Spinal anesthesia was administered at the L3-L4 or L4-L5 intervertebral space using a No. 25 Quincke needle and 10 mg of 0.5% hyperbaric bupivacaine in the prone, lateral, or sitting position. Outcomes related to sensory and motor blocks and the anesthesia success rate were compared among the three groups.ResultsSensory block reached T10 in most patients in the prone (44%) and lateral (52%) groups, compared with L1 in the sitting group (56%; p = 0.004). Motor block depth (Bromage 3) was observed in 44% (prone), 48% (lateral), and 84% (sitting) of patients (p = 0.04). Sensory block onset was slower in the prone (2.92 ± 0.87 min) and lateral (2.72 ± 0.87 min) vs. sitting (1.94 ± 1.92 min; p = 0.001). Sensory block duration was longer in the prone (79.96 ± 14.42 min) and lateral (80.28 ± 16.55 min) vs. sitting (67.64 ± 15.99 min; p = 0.007). Motor block duration was shorter in the prone (75.64 ± 12.59 min) and lateral (74.12 ± 14.20 min) vs. sitting (87.30 ± 18.24 min; p = 0.005). Hemodynamic stability was better in the prone and lateral positions (p = 0.0001). First-attempt success was higher in the sitting group (76%) vs. prone (36%) and lateral (68%) positions (p = 0.009).ConclusionThe prone and lateral positions provide higher sensory block levels and better hemodynamic stability, whereas the sitting position is associated with faster sensory block onset, deeper motor block, and higher first-attempt success. The choice of position should be individualized according to surgical requirements and patient characteristics.

Lower anogenital tract malignancies comprise anatomically adjacent but biologically heterogeneous epithelial cancers of the cervix, vulva, vagina, anal canal and penis. This narrative and conceptual Review used a transparent literature search to examine how human papillomavirus (HPV) etiology intersects with tumor lineage, somatic alterations, antigen-presentation competence, immune-cell state and spatial organization. Evidence quality is heterogeneous: cervical cancer is supported by the largest genomic, single-cell, spatial and randomized-trial literature, whereas vaginal, vulvar and penile cancers remain constrained by small retrospective cohorts and cross-site extrapolation. HPV-associated tumors retain non-self E6/E7 antigens, but viral transcription does not ensure peptide presentation, dendritic-cell priming or epithelial access by functional T cells. HPV-independent tumors lack constitutive viral antigens yet may generate mutation- or differentiation-derived immunity and checkpoint-restrained myeloid-lymphoid niches. We therefore distinguish etiological status from functional immune phenotype and critically appraise three spatial architectures-an inflamed/epithelial-penetrating pattern, a stromally excluded pattern, and an immune-desert pattern-together with an immunosuppressive functional overlay that may occur in any architecture. Clinical evidence is graded separately from mechanistic inference: immune checkpoint blockade has established roles in defined cervical and anal cancer settings, whereas therapeutic vaccines, tumor-infiltrating lymphocytes, T-cell receptor-engineered therapies, myeloid or stromal sensitization and artificial-intelligence-guided selection remain investigational or context dependent. A three-tier biomarker framework is proposed, separating routine clinical assays from extended translational profiling and exploratory single-cell, spatial and artificial-intelligence methods. This framework is hypothesis-generating, not a validated treatment-selection algorithm; assay combinations, thresholds and incremental clinical utility require prospective, multicenter and site-stratified validation.

Most existing studies focusing on human papillomavirus (HPV)-microbiota interactions are confined to the cervicovaginal tract, while mucosal microecological crosstalk at oral, anorectal and penile sites remains insufficiently summarized. This mini-review provides a narrative synthesis of current sequencing and epidemiological evidence regarding potential bidirectional interactions between HPV infection and site-specific mucosal microbiota across extra-cervicovaginal niches in both males and females. Oral HPV reshapes microbial composition in a sex-, race- and population-dependent manner; periodontal dysbiosis, high-risk HPV and Candida albicans jointly form a tripartite oncogenic axis that may contribute to oral squamous cell carcinoma, and periodontal inflammation independently elevates oral HPV susceptibility. Among men who have sex with men, pro-inflammatory anaerobes such as Bacteroides fragilis and Sneathia accumulate in anorectal HPV-related lesions, and concurrent HIV or sexually transmitted bacterial co-infections worsen mucosal dysbiosis and viral persistence. On penile skin, Corynebacterium is associated with a lower prevalence of HPV, whereas anaerobe-dominant community state types increase high-risk HPV risk, with HIV-induced baseline dysbiosis masking HPV-specific penile microbial signatures. Collectively, tissue-specific mucosal dysbiosis may represent an important co-factor linked to persistent HPV infection and subsequent malignant transformation. This review offsets long-standing sex-related and anatomical research bias, clarifies multi-site host-virus-microbe mechanisms, and provides theoretical support for developing microbiota-based biomarkers and microecological interventions to prevent non-cervical HPV-associated malignancies.

The presence of antibiotic residues in poultry meat poses a growing risk of non-compliance with maximum residue limits under international food safety regulations. However, existing screening methods to detect antibiotic overuse rely mainly on LC-MS with dispersive solid-phase extraction (dSPE) clean-up using instrumentation and sorbents that are economically inaccessible to many food-safety laboratories in resource-limited countries where such monitoring is most needed. This work develops and validates a sorbent-free, HPLC-UV multiclass screening procedure for six antibiotic residues (sulfadiazine, trimethoprim, ciprofloxacin, enrofloxacin, sulfamethoxazole and doxycycline) in chicken meat samples prior to confirmatory testing by the LC-MS technique. Three integrated methodological milestones were achieved in this work. First, mechanistic retention-time modeling equations were applied to optimize a gradient HPLC-UV separation for the studied compounds based on only six scouting runs without trial-and-error effort. Second, the extraction procedure was optimized using the Plackett-Burman screening, followed by Box-Behnken response surface design, yielding a modified QuEChERS extraction method, eliminating the dSPE step. Third, a salt-assisted liquid-liquid microextraction (SALLME) preconcentration step for the recovered analytes mitigated the sensitivity limitations of UV detection, enabling detection at food-safety-relevant concentration ranges. A robust HPLC-UV method was developed with good peak separation within 17 min using a Zorbax SB C8 column (150 × 4.6 mm, 5 µm) with a gradient system consisting of a 20 mM formate buffer (pH 3.0) and an acetonitrile-methanol (1 : 1, v/v) blend. Detection was performed using the dual-wavelength mode at 230 and 275 nm. The procedure met the linearity, repeatability and recovery validation criteria under Commission Implementing Regulation (EU) 2021/808, with recoveries of 77.7-109.2% and expanded measurement uncertainty values not exceeding 42.8%, in accordance with SANTE/11312/2021 v2. The presented sorbent-free workflow provided a validated screening platform accessible in resource-limited settings worldwide.

Cryptoglandular anal fistulas are burdensome, often recurrent and frequently treated in two stages using a loose seton before definitive sphincter-preserving surgery. Although this practice is common, high-quality evidence supporting improved healing or functional outcomes is lacking. A trial is needed to determine whether omitting routine seton placement can reduce procedures, patient burden and costs without compromising fistula closure.

S-scheme heterojunction engineering has emerged as an effective strategy for enhancing photocatalytic NO removal by facilitating charge separation while maintaining strong redox capability. Herein, an S-scheme heterojunction consisting of S-doped TiO2 nanotubes and g-C3N4 was successfully constructed via an annealing-assisted interfacial engineering strategy. Comprehensive band structure analyses using Mott-Schottky measurements, valence band X-ray photoelectron spectroscopy, and Kelvin probe force microscopy confirmed the formation of an S-scheme heterojunction between S-TiO2 and g-C3N4. The experimental results revealed a favorable band alignment and the establishment of an interfacial built-in electric field between S-TiO2 and g-C3N4, facilitating S-scheme charge transfer across the heterointerface and preserving highly reactive electrons and holes with strong reduction and oxidation capabilities, respectively, thereby promoting the generation of ·O2- and ·OH radicals. As a result, the optimized g-C3N4/S-doped TiO2 nanotube photocatalyst achieved an NO removal efficiency of 74.6%, higher than those of pristine S-TiO2 (43.4%) and g-C3N4 (53.4%), while also suppressing NO2 intermediate formation compared with previously reported TiO2- and g-C3N4-based heterojunctions. This work provides insight into the synergistic role of band alignment, interfacial built-in electric field, and S-scheme charge transfer in boosting photocatalytic NO removal performance.

A 47-year-old woman with a 6-year history of vulvar pruritus was diagnosed with vulvar extramammary Paget's disease extending to the urethra, vaginal introitus, and anal canal. Cystoscopy showed irregular mucosa limited to several millimeters from the external urethral meatus. The tumor and distal urethra were resected en bloc with a negative frozen section margin, preserving the urethral sphincter. Reconstruction used bilateral pedicled gracilis myocutaneous flaps, with the residual urethral mucosa directly anastomosed to the flap. Postoperatively, spontaneous voiding was maintained without residual urine or incontinence. At 3 years and 5 months, continence persisted without urethral stenosis or local recurrence.

High-resolution anorectal manometry (HRAM) has improved anorectal physiological assessment but remains limited by conventional pressure-based metrics that incompletely reflect the complex spatiotemporal physiology of continence and defecation. This review summarizes recent advances in artificial intelligence (AI) and machine learning and their potential to enhance HRAM interpretation and clinical decision-making.