Chitooligosaccharides and their biological activities: A comprehensive review.

The use of physical hydrogels of chitosan for skin regeneration following third-degree burns

Biomaterials and cells for cardiac tissue engineering: Current choices.

Over the last few decades, chitosan has become a good candidate for tissue engineering applications. Derived from chitin, chitosan is a unique natural polysaccharide with outstanding properties in line with excellent biodegradability, biocompatibility, and antimicrobial activity. Due to the presence of free amine groups in its backbone chain, chitosan could be further chemically modified to possess additional functional properties useful for the development of different biomaterials in regenerative medicine. In the current review, we will highlight the progress made in the development of chitosan-containing bioscaffolds, such as gels, sponges, films, and fibers, and their possible applications in tissue repair and regeneration, as well as the use of chitosan as a component for drug delivery applications.

https://www.mdpi.com/2218-273X/9/9/470/pdf

Progress in the Development of Chitosan-Based Biomaterials for Tissue Engineering and Regenerative Medicine.

This paper presents flexible pressure sensors based on free-standing and biodegradable glycine-chitosan piezoelectric films. Fabricated by the self-assembly of biological molecules of glycine within a water-based chitosan solution, the piezoelectric films consist of a stable spherulite structure of β-glycine (size varying from a few millimeters to 1 cm) embedded in an amorphous chitosan polymer. The polymorphic phase of glycine crystals in chitosan, evaluated by X-ray diffraction, confirms formation of a pure ferroelectric phase of glycine (β-phase). Our results show that a simple solvent-casting method can be used to prepare a biodegradable β-glycine/chitosan-based piezoelectric film with sensitivity (∼2.82 ± 0.2 mV kPa-1) comparable to those of nondegradable commercial piezoelectric materials. The measured capacitance of the β-glycine/chitosan film is in the range from 0.26 to 0.12 nF at a frequency range from 100 Hz to 1 MHz, and its dielectric constant and loss factor are 7.7 and 0.18, respectively, in the high impedance range under ambient conditions. The results suggest that the glycine-chitosan composite is a promising new biobased piezoelectric material for biodegradable sensors for applications in wearable biomedical diagnostics.

Glycine–Chitosan-Based Flexible Biodegradable Piezoelectric Pressure Sensor

Tissue engineering is an important therapeutic strategy to be used in regenerative medicine in the present and in the future. Functional biomaterials research is focused on the development and improvement of scaffolding, which can be used to repair or regenerate an organ or tissue. Scaffolds are one of the crucial factors for tissue engineering. Scaffolds consisting of natural polymers have recently been developed more quickly and have gained more popularity. These include chitosan, a copolymer derived from the alkaline deacetylation of chitin. Expectations for use of these scaffolds are increasing as the knowledge regarding their chemical and biological properties expands, and new biomedical applications are investigated. Due to their different biological properties such as being biocompatible, biodegradable, and bioactive, they have given the pattern for use in tissue engineering for repair and/or regeneration of different tissues including skin, bone, cartilage, nerves, liver, and muscle. In this review, we focus on the intrinsic properties offered by chitosan and its use in tissue engineering, considering it as a promising alternative for regenerative medicine as a bioactive polymer.

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Chitosan and Its Potential Use as a Scaffold for Tissue Engineering in Regenerative Medicine

Introduction  The decompressive craniectomy is a surgical strategy widely used with specific criteria to control the refractory intracranial pressure (ICP). However, it is important to warn about the presence of a postcraniectomy syndrome and analyze the risk-benefit on a long term. Case Report  A 72-year-old male patient diagnosed with a subarachnoid hemorrhage secondary to the rupture of an anterior circulation aneurysm that develops vasospasm, secondary ischemia, and edema with signs of herniation that required a decompressive craniectomy on a first step. Afterwards, the aneurysm was approached and he consequently developed hydrocephaly. A ventriculoperitoneal shunt is installed, contralateral to the craniectomy, and progressive sinking of the skin flap, there is neurological deterioration and paradoxical herniation. Its association with the clinical deterioration by bronchoaspiration did not allow the cranioplasty to resolve the ICP decompensation. Conclusions  The paradoxical herniation as part of the postcraniectomy syndrome is an increasingly common condition identified in adult patients with cortical atrophy, and who have also been treated with ventricular shunt systems. Timely cranioplasty represents the ideal therapeutic plan once the compromise from the mass effect has resolved to avoid complications derived from the decompressive craniectomy per se.

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Paradoxical Herniation in the Postcraniectomy Syndrome: Report and Literature Update.

/pdf/letter-to-the-editor-reduction-of-early-postoperative-1c0bdyix3i.pdf

Letter to the Editor: Reduction of early postoperative dysphagia via steroid use after anterior cervical surgery.

Background The peripheral hallmarks of neurofibromatosis type 1 (NF1) are Cafe au lait and solid nodular neurofibromas. The morphological behavior of these lesions could be susceptible to modification during pregnancy. The present case report describes a case of cystic transformation of a nodular neurofibroma, with progressive growth and mass effect in the anterior cervical region, which was surgically resolved without any complications. Case description A 33-year-old female patient with a known personal history of NF1, with annual control of the peripheral neurofibromas and cerebral and spinal magnetic resonance imaging follow-ups. Under genetic counseling, she decides to get pregnant following all the medical advises. Once the pregnancy is confirmed, she starts to notice the growth of one of them adjacent to the left cervical region. Such neurofibroma presented with the progressive gradual increase and in the last month, she presented dysphagia, dysphonia, and postural pain localized by the mass effect. Once the pregnancy concluded, the microsurgical approach was scheduled for resection of the lesion, where a cystic mass was found within the walls of the neurofibroma. The resection was uneventful. Conclusion The transformation of a nodular to cystic neurofibroma during pregnancy is a very rare presentation, which may exacerbate the clinical symptomatology depending on the topography of the lesion due to the mass effect it may create. This condition may alert to the recommendations and vigilance in patients with NF1, who are pregnant or are planning on a future pregnancy. The neurosurgical resolution in this region is safe and beneficial.

Neurofibromatosis type 1 and pregnancy: The transformation of a nodular to cystic neurofibroma in the cervical region.

Background: The use of automatic retractors for an anterior cervical approach with discectomy and fusion is not exempt of soft tissue complications. All of this complications consequent to the uninterrupted mechanical compression that may generate inflammation and lesions to structures such as the trachea and esophagus. The modified spatula provides security and protection under the principle of minimal invasion and manual retraction. Methods and Materials: A protective spatula was designed (8 cm x 2.5 cm) with blunt angulated borders and support in the same arms of vertebral retractors to separate the midline structures. This allows a supra-selective approach to the intervertebral space under microscopic vision and protection to the trachea and esophagus, minimizing the traumatic damage generated by the mechanical compression. Results: This variant has been applied to a consecutive series of cases of one or two levels of anterior cervical approach for discectomy and fusion (ACDF), noticing considerably less complications from the compression of the soft structures in the midline. Conclusions: This modified spatula is an alternative to be applied in ACDF cases, under the principle of minimal invasion and manual retraction, providing greater security to prevent soft tissue injury of the midline structures.

Daniel Alexander Saldaña-Koppel

Papers

Chitosan and Its Potential Use as a Scaffold for Tissue Engineering in Regenerative Medicine

Paradoxical Herniation in the Postcraniectomy Syndrome: Report and Literature Update.

Letter to the Editor: Reduction of early postoperative dysphagia via steroid use after anterior cervical surgery.

Neurofibromatosis type 1 and pregnancy: The transformation of a nodular to cystic neurofibroma in the cervical region.

Clinical Study: Use of a modified spatula in the anterior cervical discectomy and fusion to prevent damage to midline structures