Influence of Electrical Field Collector Positioning and Motion Scheme on Electrospun Bifurcated Vascular Graft Membranes.

Currently, electrospinning membranes for vascular graft applications has been limited, due to random fiber alignment, to use in mandrel-spun, straight tubular shapes. However, straight, circular tubes with constant diameters are rare in the body. This study presents a method to fabricate curved, non-circular, and bifurcated vascular grafts based on electrospinning. In order to create a system capable of electrospinning membranes to meet specific patient needs, this study focused on characterizing the influence of fiber source, electrical field collector position (inside vs. outside the mandrel), and the motion scheme of the mandrel (rotation vs. rotation and tilting) on the vascular graft membrane morphology and mechanical properties. Given the extensive use of poly(ε-caprolactone) (PCL) in tubular vascular graft membranes, the same material was used here to facilitate a comparison. Our results showed that the best morphology was obtained using orthogonal sources and collector positioning, and a well-timed rotation and tilting motion scheme. In terms of mechanical properties, our bifurcated vascular graft membranes showed burst pressure comparable to that of tubular vascular graft membranes previously reported, with values up to 5126 mmHg. However, the suture retention strength shown by the bifurcated vascular graft membranes was less than desired, not clinically viable values. Process improvements are being contemplated to introduce these devices into the clinical range.

Photopolymerizable Resins for 3D-Printing Solid-Cured Tissue Engineered Implants.

With the advent of inexpensive and highly accurate 3D printing devices, a tremendous flurry of research activity has been unleashed into new resorbable, polymeric materials that can be printed using three approaches: hydrogels for bioprinting and bioplotting, sintered polymer powders, and solid cured (photocrosslinked) resins. Additionally, there is a race to understand the role of extracellular matrix components and cell signalling molecules and to fashion ways to incorporate these materials into resorbable implants. These chimeric materials along with microfluidic devices to study organs or create labs on chips, are all receiving intense attention despite the limited number of polymer systems that can accommodate the biofabrication processes necessary to render these constructs. Perhaps most telling is the limited number of photo-crosslinkable, resorbable polymers and fabrication additives (e.g., photoinitiators, solvents, dyes, dispersants, emulsifiers, or bioactive molecules such as micro-RNAs, peptides, proteins, exosomes, micelles, or ceramic crystals) available to create resins that have been validated as biocompatible. Advances are needed to manipulate 4D properties of 3D printed scaffolds such as pre-implantation cell culture, mechanical properties, resorption kinetics, drug delivery, scaffold surface functionalization, cell attachment, cell proliferation, cell maturation, or tissue remodelling; all of which are necessary for regenerative medicine applications along with expanding the small set of materials in clinical use. This manuscript presents a review of the foundation of the most common photopolymerizable resins for solidcured scaffolds and medical devices, namely, polyethylene glycol (PEG), poly(D, L-lactide) (PDLLA), poly-ε-caprolactone (PCL), and poly(propylene fumarate) (PPF), along with methodological advances for 3D Printing tissue engineered implants (e.g., via stereolithography [SLA], continuous Digital Light Processing [cDLP], and Liquid Crystal Display [LCD]).

Influence of Controlled Cooling in Bimodal Scaffold Fabrication Using Polymers with Different Melting Temperatures.

The combination of different materials and capabilities to manufacture at several scales open new possibilities in scaffold design for bone regeneration. This work is focused on bimodal scaffolds that combine polylactic acid (PLA) melt extruded strands with polycaprolactone (PCL) electrospun fibers. This type of bimodal scaffold offers better mechanical properties, compared to the use of PCL for the extruded strands, and provides potential a means for controlled drug and/or growth factor delivery through the electrospun fibers. The technologies of fused deposition modeling (FDM) and electrospinning were combined to create 3D bimodal constructs. The system uses a controlled cooling system allowing the combination of polymers with different melting temperatures to generate integrated scaffold architecture. The thermoplastic polymers used in the FDM process enhance the mechanical properties of the bimodal scaffold and control the pore structure. Integrated layers of electrospun microfibers induce an increase of the surface area for cell culture purposes, as well as potential in situ controlled drug and/or growth factor delivery. The proposed bimodal scaffolds (PLA extruded strands and PCL electrospun fibers) show appropriate morphology and better mechanical properties when compared to the use of PCL extruded strands. On average, bimodal scaffolds with overall dimensions of 30 × 30 × 2.4 mm³ (strand diameter of 0.5 mm, strand stepover of 2.5 mm, pore size of 2 mm, and layer height of 0.3 mm) showed scaffold stiffness of 23.73 MPa and compression strength of 3.85 MPa. A cytotoxicity assay based human fibroblasts showed viability of the scaffold materials.

Heterotopic sebaceous glands in the esophagus, a very rare histopathological diagnosis: a case report and review of the literature.

Sebaceous glands are very rarely found in the esophagus. Existing reports do not contain sufficient epidemiological, etiological, clinical, or prognostic data. Its histogenesis suggests heterotopia or metaplasia. Despite its extreme rarity, correct and generally easy identification enables establishing the proper patient monitoring.

Implante de cardiodesfibrilador por vía transauricular: descripción de un caso / Placement of an Implantable Cardioverter Defibrillator Thorough a Transatrial Approach: a Case Report

La trombosis de la vena cava superior es infrecuente, pero su aparición dificulta la vía de acceso para el implante de marcapasos y desfibriladores. Existen alternativas cuando no se puede utilizar la vía endovascular y la vía epicárdica es la de elección. Sin embargo, se describieron implantes de catéteres de desfibrilador por vía transauricular por toracotomía mínima con buenos resultados a largo plazo y con el logro de un umbral de desfibrilación adecuado. En esta presentación se describe el caso de un paciente con antecedentes de cardiopatía chagásica e implante de un marcapasos bicameral por enfermedad binodal que necesita un desfibrilador. Debido a que se trata de un paciente joven con accesos dificultosos se decidió utilizar la vía transauricular por toracotomía mínima conservando el catéter auricular para estimulación y sensado.

Thrombosis of the superior vena cava is an infrequent condition; yet, its presence prohibits placement of pacemakers and defibrillator devices. The epicardial approach is indicated when the venous access for lead placement is compromised. However, implantable cardioverter device placement using minithoracotomy has been described with favorable long-term outcomes, achieving an adequate defibrillation threshold. We describe the case of a patient with a history of Chagas cardiomyopathy and dual-chamber pacemaker placement due to coexisting sinus node and atrioventricular node dysfunction. We decided to use the transatrial approach via minithoracotomy leaving the atrial lead for sensing electrical activity and delivering stimulation pulses.

Criocirugía como alternativa terapéutica en leishmaniasis cutánea atípica / Cryosurgery as a therapeutic alternative in atypical cutaneous leishmaniasis

Se estudiaron en forma prospectiva 15 pacientes, que asistieron a la consulta externa de Servicio de Dermatología del Hospital Escuela, en un período de 16 semanas, todos con diagnóstico clínico y laboratorial de Leishmaniasis Cutánea Atípica. Confirmado dicho diagnóstico se procedió a tratar con nitrógeno liquído directamente sobre la lesión, utilizando aplicadores de algodón, hasta lograr un halo de 3mm. a la periferia de cada lesión objetivo logrado en 40 segundos de iniciada la aplicación con variantes mínimas según el caso. Se dio seguimiento con frotis y cultivo a la tercera y sexta semana posterior a la aplicación inicial obteniendo en total un resultado de negatividad del 100 por ciento. En tal virtud, consideramos que un resultado del 100 por ciento de negativizaciones que arrojó el método es contundente y da base racional para continuar realizando este estudio con universos mayores

Uso sistémico y tópico de 5-metoxipsoralen: repigmentación del vitiligo con 5-MOP tópico

El vitiligo es una hipomelanosis y amelanosis idiopática adquirida de la piel que afecta un alto porcentaje de la población. La fotoquimioterapia estimula la melanogénesis, la proliferación y la migración de melonocitos. Estudios recientes han mostrado exelente repigmentación con PUVA empleando 5-Metoxipsoralen oral. Este método tiene la ventaja de que produce muy poca fototoxicidad cutánea y náuseas. Hemos tratados 30 pacientes de vitiligo localizado con fotoquimioterapia tópica, empleando una preparación líquida nueva de 5-Metoxipsoralen que ha mostrado ser efectiva en la repigmenación de un número substancial de pacientes. (76.6%)

Psoral en oral en la fotoquimioterapia del prurigo actínico / Psoral en oral on the photochemoterapy of atinic prurigo

La fotoquimioterapia oral resultó en limpieza del prúrigo actínico en veinte pacientes. Bajo condiciones externas que previamente habían producido severas erupciones, diciocho pacientes (90%) no desarrollaron ninguna erupción. Uno tuvo ligera recurrencia y otro tuvo intensa recurrencia después de amplia exposición solar sin protección. El tratamiento con PUVA fue bien tolerado y no se observaron severos efectos colaterales. Los pacientes no recibieron tratamiento aedicional ese año. Cuando regresaron, ocho meses después, con nuevas erupciones de PA, fueron tratados con PUVA otra vez

Psoral en oral en la fotoquimioterapia del prurigo actínico / Psoral en oral on the photochemoterapy of atinic prurigo

La fotoquimioterapia oral resultó en limpieza del prúrigo actínico en veinte pacientes. Bajo condiciones externas que previamente habían producido severas erupciones, diciocho pacientes (90%) no desarrollaron ninguna erupción. Uno tuvo ligera recurrencia y otro tuvo intensa recurrencia después de amplia exposición solar sin protección. El tratamiento con PUVA fue bien tolerado y no se observaron severos efectos colaterales. Los pacientes no recibieron tratamiento aedicional ese año. Cuando regresaron, ocho meses después, con nuevas erupciones de PA, fueron tratados con PUVA otra vez (AU)

Los eritemas figurados. / The figurate erythemas

Los eritemas anulares se pueden definir como erupciones caracterizadas por lesiones circinadas, arciformes y policiclicas que pueden ser fijas o migratorias y producidas por una reaccion de hipersensibilidad a antigenos endogenos o exogenos