Self-Assembled Hydrogel Membranes with Structurally Tunable Mechanical and Biological Properties.

Using supramolecular self-assembled nanocomposite materials made from protein and polysaccharide components is becoming more popular because of their unique properties, such as biodegradability, hierarchical structures, and tunable multifunctionality. However, the fabrication of these materials in a reproducible way remains a challenge. This study presents a new evaporation-induced self-assembly method producing layered hydrogel membranes (LHMs) using tropocollagen grafted by partially deacetylated chitin nanocrystals (CO-g-ChNCs). ChNCs help stabilize tropocollagen's helical conformation and fibrillar structure by forming a hierarchical microstructure through chemical and physical interactions. The LHMs show improved mechanical properties, cytocompatibility, and the ability to control drug release using octenidine dihydrochloride (OCT) as a drug model. Because of the high synergetic performance between CO and ChNCs, the modulus, strength, and toughness increased significantly compared to native CO. The biocompatibility of LHM was tested using the normal human dermal fibroblast (NHDF) and the human osteosarcoma cell line (Saos-2). Cytocompatibility and cell adhesion improved with the introduction of ChNCs. The extracted ChNCs are used as a reinforcing nanofiller to enhance the performance properties of tropocollagen hydrogel membranes and provide new insights into the design of novel LHMs that could be used for various medical applications, such as control of drug release in the skin and bone tissue regeneration.

Total hip replacement in a cat with contralateral pelvic limb amputation.

Case summary: A 10-year-old male neutered domestic shorthair cat, which had previously had its contralateral pelvic limb amputated, was treated for coxofemoral degenerative joint disease (DJD) with a total hip replacement. The long-term outcome was favourable and no complications were recorded. Interestingly, the contralateral coxofemoral joint left at the time of the previous amputation developed DJD and became a source of pain for the cat and was subsequently excised. Relevance and novel information: This case report shows that total hip replacement is a viable option in cats with coxofemoral DJD and a contralateral limb amputation. Retained joints in amputated limbs may develop osteoarthritis and be a source of pain for a cat.

Locking Compression Plate Fixation of Feline Acetabular Fractures: Application, Complications and Perioperative Outcome.

OBJECTIVES: The aim of this study was to report the use, complications and perioperative outcome of locking compression plates (LCP) for acetabular fracture fixation in feline patients. STUDY DESIGN: Medical records were reviewed for cats presented with acetabular fractures between 2011 and 2019. Only cases that involved open reduction and internal fixation with at least one LCP and had a minimum of 5-week postoperative follow-up were included. Long-term follow-up was based on the Feline Musculoskeletal Pain Index. RESULTS: Fifteen cats with 15 acetabular fractures met the inclusion criteria. Locking compression plates were used as a sole method of fixation in 11/15 cases, while with other ancillary implants in 4/15 cases. There were two minor complications related to the LCP consisting of a single screw backing out. Two major perioperative complications not related to the locking implants were described and required further surgical treatment. At the last clinical follow-up (median 46 days: 38-88 days), function was described as full for 7/15 cats, and acceptable for 8/15 cats. The Feline Musculoskeletal Pain Index questionnaire was completed by 9/15 owners at a median of 2,332 days; all owners reported their cats had minimal impairment. CLINICAL SIGNIFICANCE: Based on our results, LCP is a suitable implant for acetabular fracture fixation in cats, associated with a satisfactory outcome. Complications were similar to previously reported with other methods.

Locking Plate Fixation for Canine Acetabular Fractures.

OBJECTIVE: The aim of this study was to document application of locking plates for stabilization of acetabular fractures along with complications and clinical outcomes. We hypothesized that complications and clinical outcomes would be comparable to historical reports using non-locking plate and screw constructs. STUDY DESIGN: Medical records of dogs presented with acetabular fractures at a single referral centre between 2010 and 2018 were reviewed. Cases surgically managed by open reduction and internal fixation, involving placement of at least one locking plate and screws, were included. Signalment, fracture classification, type of implant used, additional methods of stabilization, along with complications and neurological deficits, were collected. Long-term follow-up was based on Liverpool Osteoarthritis in Dogs questionnaire. RESULTS: Eighteen acetabula were repaired in 17 dogs. Locking implants were VetLOX (4/18), string-of-pearls (7/18) and locking compression plates (7/18). Locking plates and screws were used as the sole method of fixation in 10/18 acetabula, and as adjunctive fixation with other implants in 8/18 acetabula. Two minor complications and one catastrophic complication were reported. Sixteen of seventeen dogs returned to function with radiographic documentation of fracture healing. Complication rate was comparable to historic reports using non-locking implants. Long-term outcomes assessed by Liverpool Osteoarthritis in Dogs questionnaire were positive in most cases. CONCLUSION: Locking plates are a viable means of stabilizing acetabular fractures in dogs and can provide positive clinical outcomes. Surprisingly, problems including inaccurate fracture reduction and implant loosening were not fully avoided by use of locking implants but incidence was low.

Impact of Hydrogen Bonds Limited Dipolar Disorder in High-k Polymer Gate Dielectric on Charge Carrier Transport in OFET.

The paper contributes to the characterization and understanding the mutual interactions of the polar polymer gate dielectric and organic semiconductor in organic field effect transistors (OFETs). It has been shown on the example of cyanoethylated polyvinylalcohol (CEPVA), the high-k dielectric containing strong polar side groups, that the conditions during dielectric layer solidification can significantly affect the charge transport in the semiconductor layer. In contrast to the previous literature we attributed the reduced mobility to the broader distribution of the semiconductor density of states (DOS) due to a significant dipolar disorder in the dielectric layer. The combination of infrared (IR), solid-state nuclear magnetic resonance (NMR) and broadband dielectric (BDS) spectroscopy confirmed the presence of a rigid hydrogen bonds network in the CEPVA polymer. The formation of such network limits the dipolar disorder in the dielectric layer and leads to a significantly narrowed distribution of the density of states (DOS) and, hence, to the higher charge carrier mobility in the OFET active channel made of 6,13-bis(triisopropylsilylethynyl)pentacene. The low temperature drying process of CEPVA dielectric results in the decreased energy disorder of transport states in the adjacent semiconductor layer, which is then similar as in OFETs equipped with the much less polar poly(4-vinylphenol) (PVP). Breaking hydrogen bonds at temperatures around 50 °C results in the gradual disintegration of the stabilizing network and deterioration of the charge transport due to a broader distribution of DOS.

The Contribution of Adipose Tissue-Derived Mesenchymal Stem Cells and Platelet-Rich Plasma to the Treatment of Chronic Equine Laminitis: A Proof of Concept.

Laminitis, a highly debilitating disease of the foot in ungulates, is characterized by pathological changes of the complex lamellar structures that maintain the appendicular skeleton within the hoof. Laminitis is a multifactorial disease that involves perturbation of the vascular, hematological, and inflammatory homeostasis of the foot. Interestingly, the pathogenesis of the disease resembles what is observed in metabolic syndromes and sepsis-induced organ failure in humans and animals. We hypothesized that local administration of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) might contribute to establishing an anti-inflammatory and pro-angiogenic environment, and could stimulate the injured tissue in order to restore its functional integrity. According to this assumption, an experimental protocol based on the local intravenous administration of adipose tissue-derived MSCs (aMSCs) in combination with PRP was developed for the treatment of horses affected by chronic laminitis. Nine horses with severely compromised venograms (showing grade III and IV laminitis) that had been unsuccessfully treated with conventional therapies were enrolled. aMSCs and PRP (15 × 106 cells resuspended in 15 mL of PRP) were injected into the lateral or medial digital vein three times, at one-month intervals. The first administration was performed with allogeneic aMSCs, while for the following administrations, autologous aMSCs were used. There was no adverse short-term reaction to the intravenous injection of aMSCs. In the long term, venograms outlined, in all subjects, a progressive amelioration of the vascularization of the foot. An improvement in the structure and function of the hoof was also observed. No adverse events were reported during the follow-up, and the horses returned to a comfortable quality of life. Although the number of animals enrolled in the study is limited, both clinical observations and venography demonstrated an enhancement in the condition of all horses, suggesting that the regenerative therapies in chronic laminitis could be useful, and are worthy of further investigation.