Development of bone surrogates by material extrusion-based additive manufacturing to mimic flexural mechanical behaviour and fracture prediction via phase-field approach.

BACKGROUND AND OBJECTIVE: The limited availability of human bone samples for investigation leads to the demand for alternatives. Bone surrogates are crucial in promoting research on the intricate mechanics of osseous tissue. However, solutions are restricted to commercial brands, which frequently fail to faithfully replicate the mechanical response of bone, or oversimplified customised simulants designed for a specific application. The manufacturing and assessment of reliable bone surrogates made of polylactic acid via material extrusion-based additive manufacturing are presented in this work. METHODS: An experimental and numerical study with 3D-printed dog-bone and prismatic specimens was carried out to characterise the polymeric feedstock and analyse the influence of process parameters under three-point bending and quasi-static conditions. Besides, three porcine rib samples were considered as a reference for the development of the artificial bones. Bone surrogates were manufactured from the 3D-scanned real bone geometries. In order to reproduce the trabecular and cortical bone, a lattice structure for the infill and a compact shell surrounding the core were employed. Infill density and shell thickness were evaluated through different printing configurations. Additionally, a computational analysis based on the phase-field approach was conducted to simulate the experimental tests and predict fracture. The modelling considered homogenisation of the infill material. RESULTS: Outcomes demonstrated the potential of the presented methodology. Maximum force and flexural stiffness were compared to real bone properties to find the optimal printing configuration, replicating the flexural mechanical behaviour of bone tissue. Certain configurations accurately reproduce the studied properties. Regarding the numerical model, strength and stiffness prediction was validated with experimental results. CONCLUSIONS: The presented methodology enables the manufacturing of artificial bones with accurate geometries and tailored mechanical properties. Furthermore, the described modelling strategy offers a powerful tool for designing bone surrogates.

Thymopoietin Beta and Gamma Isoforms as a Potential Diagnostic Molecular Marker for Breast Cancer: Preliminary Data.

Thymopoietin (TMPO) is an inner nuclear membrane protein, the coding gene named equally, can give arise to six isoforms by alternative splicing. This gene has been found up regulated in several types of cancer. At present work, we evaluated the TMPO isoforms generated by alternative splicing as well as the protein signal detection in breast cancer samples. TMPO expression was analyzed by immunohistochemistry in tissue microarray containing 46 breast tissue samples including normal (n = 6), benign lesions (n = 18) (fibroadenomas (n = 6), fibrocystic changes (n = 6), ductal hyperplasias (n = 6)) and breast carcinoma (n = 22). Isoforms -α, -ß and -γ of TMPO were evaluated using RT-PCR; clinical-pathological correlation analysis were done by mean of X(2). Neither the normal nor the benign lesions of the breast showed positive TMPO immunodetection, whilst 45 % of the breast carcinomas were immunopositive (p = 0.000), nine of ten positives carcinomas correspond to the Luminal A subtype. Further, alpha isoform was present in all breast samples analyzed; however, beta and gamma isoforms were only present in ten (p = 0.003) and 17 (p = 0.000), respectively, in the breast cancer samples. According with the present data, we suggest that TMPOß and -γ isoforms could provide a potential reliable diagnostic marker for breast cancer.

[Aggressive angiomyxoma of the vulva. Case report and literature review]. / Angiomixoma agresivo de la vulva. Informe de un caso y revisión de la bibliografía.

Aggressive angiomyxoma is a rare vulvovaginal, perineal or pelvic mesenchymal neoplasm with a marked tendency to local recurrence but does not metastasize. A case of an aggressive angiomyxoma of vulva in a 39-years-old women with an illness of one year prior to examination, with a slow and progressive growth of the left vulvar region, without other symptoms. During physical examination, a piriform tumor of 15x10 cm was found, located on the left labia majora, soft tissue dependent. Wide resection of the tumor were performed. Hystopathology reported an aggressive angiomyxoma of the vulva, with tumor in resection margins. The patient was treated with a 65Gy postsurgical radiotherapy and gosereline 3.6 mg monthly, during 6 cycles. Aggressive angiomyxoma is a rare neoplasm 150 cases has been reported. The treatment is surgical resection. Radiotherapy and hormonal adyuvant is not fully stablished.