Embedding magnesium metallic particles in polycaprolactone nanofiber mesh improves applicability for biomedical applications.

Magnesium (Mg) metal is of great interest in biomedical applications, especially in tissue engineering. Mg exhibits excellent in vivo biocompatibility, biodegradability and, during degradation, releases Mg ions (Mg2+) with the potential to improve tissue repair. We used electrospinning technology to incorporate Mg particles into nanofibers. Various ratios of Mg metal microparticles (<44 µm diameter) were incorporated into nanofiber polycaprolactone (PCL) meshes. Physicochemical properties of the meshes were analyzed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), mechanical tensile testing, X-ray diffractometry and UV-VIS spectrophotometry. Biological properties of meshes were evaluated in vitro and in vivo. Under mammalian cell culture conditions, Mg-containing meshes released hydrogen gas and relative amounts of free Mg2+ that reflected the Mg/PCL ratios. All meshes were non-cytotoxic for 3T3 fibroblasts and PC-12 pheochromocytoma cells. In vivo implantation under the skin of mice for 3, 8 and 28 days showed that Mg-containing meshes were well vascularized, with improved measures of inflammation and healing compared to meshes without Mg. Evidence included an earlier appearance and infiltration of tissue repairing macrophages and, after 28 days, evidence of more mature tissue remodeling. Thus, these new composite nanofiber meshes have promising material properties that mitigated inflammatory tissue responses to PCL alone and improved tissue healing, thus providing a suitable matrix for use in clinically relevant tissue engineering applications. STATEMENT OF SIGNIFICANCE: The biodegradable metal, magnesium, safely biodegrades in the body, releasing beneficial byproducts. To improve tissue delivery, magnesium metal particles were incorporated into electrospun nanofiber meshes composed of a biodegradable, biocompatible polymer, polycaprolactone (PCL). Magnesium addition, at several concentrations, did not alter PCL chemistry, but did alter physical properties. Under cell culture conditions, meshes released magnesium ions and hydrogen gas and were not cytotoxic for two cell types. After implantation in mice, the mesh with magnesium resulted in earlier appearance of M2-like, reparative macrophages and improved tissue healing versus mesh alone. This is in agreement with other studies showing beneficial effects of magnesium metal and provides a new type of scaffold material that will be useful in clinically relevant tissue engineering applications.

Pseudoporfiria asociada a hemodialisis / Pseudoporfiria associated with hemodialysis

La pseudoporfiria es una dermatosis ampollar poco frecuente con similares caracter¡sticas cl¡nicas e histopatol¢gicas a las de la porfiria cut nea tarda pero con cifras normales de porfirinas. Se presenta el caso de una paciente con pseudoporfiria asociada a hemodi lisis que fue tratada con N-acetilciste¡na.

The pseudoporphyria is a bullous dermatosis rare with similar clinical and histopathologic features to the ofporphyria cutanea tarda but with normal numbers of porphyrins. The case of a patient is presented with pseudoporphtyria associated with hemodialysis who was treated with N-acetylcysteine.

Emerging adults' lived experience of formative family stress: the family's lasting influence.

In this article, we use a phenomenology framework to explore emerging adults' formative experiences of family stress. Fourteen college students participated in a qualitative interview about their experience of family stress. We analyzed the interviews using the empirical phenomenological psychology method. Participants described a variety of family stressors, including parental conflict and divorce, physical or mental illness, and emotional or sexual abuse by a family member. Two general types of parallel processes were essential to the experience of family stress for participants. First, the family stressor was experienced in shifts and progressions reflecting the young person's attempts to manage the stressor, and second, these shifts and progressions were interdependent with deeply personal psychological meanings of self, sociality, physical and emotional expression, agency, place, space, project, and discourse. We describe each of these parallel processes and their subprocesses, and conclude with implications for mental health practice and research.