Comprehensive feasibility evaluation of small-diameter 3D templated vascular graft via physical characterizations andin-vivoexperiments.

3D printing (3DP) technology for tissue engineering applications has been extensively studied for materials and processes. However, clinical application to the vascular system was limited owing to mechanical inconsistency and toxicity. Here, we characterized 3D templated artificial vascular grafts (3D grafts), which were fabricated by an integrative method involving 3DP, dip coating, and salt leaching method. The as-fabricated grafts were featured with micrometer-scale porosity enabling tissue-mimetic mechanical softness comparable with native blood vessels. In terms of mechanical properties and water permeability, the fabricated 3D grafts exhibited comparable or superior performances compared to the commercialized grafts. Furthermore, thein-vivostability of the 3D graft was validated through a toxicity test, and the small-diameter 3D graft was transplanted into a rat to confirm the implant's performance. Overall, the experimental results demonstrated the clinical feasibility of the 3D graft with retaining the mechanical biocompatibility and also revealed the possibility of patient-specific customization.

Control of the Biodegradability of Piezoelectric Peptide Nanotubes Integrated with Hydrophobic Porphyrin.

Diphenylalanine (FF) is a piezoelectric material that is widely known for its high piezoelectric constant, self-assembly characteristics, and ease of manufacture. Because of its biocompatible nature, it is useful for implantable applications. However, its use in real applications is challenging because it degrades too easily in the body due to its solubility in water (0.76 g/mL). Upon incorporation of hydrophobic and biocompatible porphyrins into the FF, the degradability of the piezoelectric FF and their piezoelectric nanogenerators (PENGs) is controlled. Porphyrin-incorporated FFs are also formed as piezoelectric nanostructures well aligned on the substrate through self-assembly, and their piezoelectric properties are comparable to those of FF. The FF-based PENG degrades in only 5 min, whereas the FF-porphyrin-based PENG produces a stable output for >15 min in phosphate-buffered saline. This strategy for realizing biodegradable functional materials and devices with tunable degradation rates in the body can be applied to many implantable electronics.

Soft Biomimetic 3D Free-Form Artificial Vascular Graft Using a Highly Uniform Microspherical Porous Structure.

This study presents a biomimetic 3D customizable artificial vascular graft with a highly porous and uniform microscale structure. The structural features were obtained by dip coating of a highly close-packed microsphere suspension on a 3D printed sacrificial template. Considering the structured arrangement of microspherical porogens in the coating layer, the microsphere-leached constructs showed higher uniformity and porosity than the conventionally particulate-leached structures, leading to ultrasoft mechanical compliance. Considering biomechanical compatibility, the resulting elastic moduli were at the sub-MPa level, comparable with those of native vascular tissues. In addition, the developed porous graft was reinforced selectively at the edge regions using a nonporous coating to secure its practical sutureability for clinical use. The sufficiently low cytotoxicity was clinically confirmed to alleviate the stiffness mismatch issues at the anastomotic interface between the native tissue and the artificial graft, thus overcoming the relevant clinical complications. Furthermore, the overall superior properties could be implemented on the 3D printed template for patient-specific medicare, thus implying the manufacturability of patient-specific vascular grafts.

Tarsal tunnel syndrome in patients with fibromyalgia.

OBJECTIVES: This study aims to evaluate the frequency of tarsal tunnel syndrome (TTS) in fibromyalgia (FM) patients. PATIENTS AND METHODS: In this prospective study, we investigated paresthesia of the foot, sensory and motor deficits, atrophy of the abductor hallucis muscle, and the presence of Tinel's sign in 76 female FM patients (mean age 39.3±7.4 years; range, 24 to 52 years) and 60 sex-matched healthy control subjects (mean age 38.6±8.2 years; range, 28 to 49 years) without FM between July 2016 and June 2018. Bilateral electrophysiological studies of the tibial, peroneal, sural, and medial as well as lateral plantar nerves were performed. RESULTS: Paresthesia was observed in 22 FM patient extremities and four control subject extremities (p=0.002). Local tenderness at the tarsal tunnel was observed in 12 FM patient extremities and two control subject extremities (p=0.021). TTS was detected electrophysiologically in 14 FM patient extremities and two control subject extremities (p=0.009). CONCLUSION: Paresthesia of the foot and local tenderness at the tarsal tunnel were significantly more prevalent in FM patients than in healthy control subjects. TTS is statistically more frequent in patients with FM than the normal population. The potential comorbidities of TTS and paresthesia of the foot should be carefully examined in FM patients.

Recurrent Guillain-Barré Syndrome Following Urinary Tract Infection by Escherichia coli.

Recurrent Guillain-Barré syndrome (GBS) is a rare, immune-mediated disease of the peripheral nervous system. It has been reported to occur at intervals ranging from four months to 10 years; published case studies suggest that 1%-6% of patients who have had GBS will experience recurrent attacks. The most commonly identified infections coinciding with GBS are Campylobacter jejuni, Haemophilus influenzae, Mycoplasma pneumonia, and cytomegalovirus, while an antecedent infection with Escherichia coli is very uncommon. In this case report, we present a rare episode of recurrent GBS, which followed a urinary tract infection (UTI) by E. coli, and an accompanying literature review. A 75-year-old woman with a prior history of acute motor axonal neuropathy (AMAN), a subtype of GBS, presented with subsequent weakness of limbs and areflexia following 10 days of fever, frequency, and dysuria. Base on nerve conduction studies, cerebrospinal fluid analysis and other clinical investigation, we diagnosed the patient with recurrent GBS caused by E. coli. The patient recovered with mild subjective weakness following treatment of intravenous immunoglobulin with ceftriaxone. We suggest that E. coli causes UTI could be one of the diverse trigger factors involved in recurrent GBS.