Non-homologous end joining (NHEJ) is a major pathway of DNA double strand break (DSB) repair, capable of directly joining both damaged strands of DNA through the coordinated activities of repair factors that detect the termini, physically bridge them together, and perform the chemistry necessary to complete repair. NHEJ is capable of repairing a variety of damaged DNA, employing various accessory end-processing factors to resolve chemically blocked ends, trim overhangs, and fill gaps in order to achieve directly ligatable DNA ends. To investigate the molecular mechanisms underlying end-processing, we determine the cryo-EM structure of the NHEJ specific polymerase Pol λ bound to the short-range synaptic complex, detailing the mode of its recruitment to the complex as well as a putative model for its activity. Furthermore, the coordinated end-processing activities of the short-range (SR) synaptic complex simultaneously bound by both Pol λ and PNKP, another accessory factor, demonstrates the ability of NHEJ to form large, multifunctional repair complexes capable of processing a variety of different DNA end structures to effect repair.

Primary malignancy in accessory breast tissue is an infrequent diagnosis representing less than 1% of all breast cancers and most commonly presents with a palpable mass in the axilla. Furthermore, a concurrent second primary breast cancer found in accessory breast tissue is an extremely rare phenomenon, although reports of these are on the rise. Extra-mammary sites where second primary breast malignancies have been reported include the inframammary fold, the abdomen and even the vulva. When an ectopic immunobreast malignancy is suspected, triple assessment is the standard approach to investigation. However, there are no specific treatment guidelines, and it therefore follows the same guidelines as for pectoral breast cancer. Here, we present a report of a 71-year-old female being treated for a left breast cancer, diagnosed with a concurrent second primary breast carcinoma in the right upper quadrant of the abdominal wall, which was surgically managed with wide local excision and sentinel lymph node biopsy. This case highlights the importance of maintaining a high index of suspicion during assessment of these patients in order to establish the correct diagnosis at an early stage.

Staphylococcus aureus, a gram-positive bacterium, which causes skin and soft tissue infections in hospital and community settings, is one of the leading threats in public health because of their proficiency to develop biofilms as an adaptive feature.

A 1-year-and-9-month-old Golden Retriever presented with a 9-month history of right thoracic limb lameness. Radiographs revealed a monostotic, expansile lesion of the right accessory carpal bone (ACB). A computed tomography (CT) confirmed the aggressive nature of the lesion, demonstrating multifocal moth-eaten osteolysis, sclerosis, periosteal reaction, and flexor carpi ulnaris tendinopathy. Differential diagnoses included the ischemic necrosis of the ACB, osteomyelitis, and primary bone neoplasia. Histopathology confirmed osteonecrosis. This case highlights the value of CT in evaluating aggressive carpal lesions and identifies ischemic necrosis as an important differential diagnosis. This case represents the first CT description of this disease in dogs.

ObjectiveTo identify risk factors for flexible gastrointestinal endoscope reprocessing failure and develop a practical risk-scoring model for the early identification of high-risk reprocessing cycles.MethodsThis retrospective observational study, conducted from January to December 2025 at three endoscopy centers, included 2744 reprocessing cycles that adhered to WS 507-2016. Internal validation was performed using a split-sample approach, with 70% of the sample used for model derivation and 30% for validation. Predictors were selected using univariable and multivariable logistic regression and converted into an integer-based scoring system, with the optimal cutoff determined using the Youden index. Reporting followed the Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis and Strengthening the Reporting of Observational Studies in Epidemiology guidelines, and the study was conducted in accordance with the Declaration of Helsinki.ResultsAmong the 2744 eligible reprocessing cycles, 682 (24.85%) exhibited reprocessing failure. Six independent predictors were identified: brushing personnel, washer-disinfector type, accessory use frequency, prior repair history, time from removal to reprocessing, and staff age. The scoring system, with a range of -2 to 18, achieved an area under the curve of 0.834 (95% confidence interval: 0.804-0.864) in the validation cohort. At a cutoff of ≥10, sensitivity was 0.725, specificity was 0.808, positive predictive value was 0.554, and negative predictive value was 0.899. Calibration was satisfactory based on the Hosmer-Lemeshow test and bootstrap analysis.ConclusionsThe internally validated scoring system enables the early identification of high-risk reprocessing cycles and may support quality improvement efforts. However, external validation is needed to assess its generalizability.

Myoepithelioma is an extremely rare benign tumor of the salivary glands that poses a diagnostic challenge because its clinical, radiologic, and cytopathologic characteristics may resemble those of several other salivary gland tumors. Accessory parotid myoepithelioma is even rarer. A 24-year-old female patient presented with a five-year history of a gradually increasing, painless swelling in the right mid-cheek region. Clinical examination revealed a firm, well-demarcated, nontender swelling in the right mid-cheek region without evidence of facial nerve involvement. Ultrasonographic evaluation revealed a multilocular mass superior to the right parotid gland, and fine-needle aspiration cytology was suggestive of pleomorphic adenoma. The patient underwent superficial parotidectomy with complete excision of the tumor while preserving the facial nerve branches. Histopathological examination confirmed the diagnosis of myoepithelioma, demonstrating sheets and cords of myoepithelial cells within a collagenous stroma. The postoperative period was uneventful, with no recurrence or facial nerve dysfunction during the 2.5 years of follow-up. This report highlights the importance of including accessory parotid tumors in the differential diagnosis of cheek masses. Histopathological examination is essential for establishing a definitive diagnosis, and complete surgical excision remains the optimal management strategy.

Acquired distichiasis is an uncommon eyelid disorder characterized by an accessory row of eyelashes arising from the meibomian gland orifices, most often in the setting of chronic inflammatory or cicatricial disease. We report a case of a 65-year-old woman with longstanding dermatomyositis, recurrent periocular inflammation, and episodes of blepharitis who developed bilateral upper-eyelid distichiasis. Review of clinical photographs from 2020 and from a severe periocular flare in 2023 showed no clearly visible accessory row. At follow-up in January 2026, clinical and dermoscopic examination demonstrated bilateral accessory rows of long, pigmented eyelashes, findings consistent with acquired distichiasis. The patient had no ocular irritation or visual symptoms, and ophthalmologic evaluation found neither trichiasis nor corneal involvement. There was no history of Stevens-Johnson syndrome, ocular cicatricial pemphigoid, trachoma, chemical injury, or eyelid surgery. However, recurrent blepharitis and previous exposure to docetaxel in 2018 were important alternative or contributing factors. Chronic periocular inflammation associated with dermatomyositis may have promoted eyelid margin remodeling and metaplastic changes in the meibomian glands, but a causal relationship cannot be established from a single case. Because the patient was asymptomatic and had no corneal complications, observation with regular ophthalmologic monitoring was selected. This case highlights the need to examine the eyelid margins in patients with chronic periocular inflammation and to consider both inflammatory and treatment-related contributors to acquired distichiasis.

Smear microscopy and culture are conventional methods of tuberculosis (TB) diagnostics. Microscopy is fast and inexpensive but has low sensitivity, whereas culture is highly sensitive but may take several weeks. Molecular diagnostic (MDx) methods were widely introduced into TB diagnostics much later, in the early 2010s, when the GeneXpert system was launched. MDx methods combine the benefits of the conventional methods. Furthermore, significant developments have occurred in recent years. The current selection of available rapid MDx methods covers the full range of TB diagnostics: detection of pulmonary and extrapulmonary TB, narrow- to broad-range rapid drug susceptibility testing, mycobacterial species identification, and Mycobacterium tuberculosis (MTB) strain typing. Several issues-often focusing on high assay costs-have still prevented the complete roll-out of MDx methods over conventional methods in both low-resource, high-incidence settings and high-resource, low-incidence settings. This review covers topics related to molecular detection of MTB and MTB drug resistance directly from clinical specimens. The aim of the review is to describe currently available methods, how they perform, and what key issues must be addressed for more optimal implementation. Overall, MDx methods currently represent an essential but often accessory tool in the detection of TB and MTB drug resistance. At present, several limitations-including diagnostic equivalence with the reference method, breadth of drug resistance testing, treatment monitoring, and accessibility due to analysis costs and assay complexity-still hinder efficient replacement of the conventional smear microscopy and culture methods. However, new advances in testing methods and strategies are continuously being made.