In Vitro Evaluation of the Biological Availability of Hyaluronic Acid Polyethylene Glycols-Cross-Linked Hydrogels to Bovine Testes Hyaluronidase.

During last years, hyaluronic acid- (HA-) based dermal fillers have grown rapidly and continuously, as reported by the American Society of Aesthetic Plastic Surgery (ASAPS). In fact, HA fillers are considered the gold standard technique for soft tissue augmentation, deep skin hydration, and facial recontouring, playing a key role as an alternative to plastic surgery. HA fillers are less invasive, more biocompatible, and safer and with a more natural and immediate result if compared to plastic surgery. Hence, the safety of HA-based dermal fillers plays a crucial role, mostly in terms of biocompatibility and adjustability in case of unpleasant results and side effects such as, tyndall effect, edema, or granulomas. Hyaluronidase is a naturally occurring enzyme, present in the human body, and can degrade HA fillers avoiding more severe complications. In this article, we analyzed the bioavailability of hyaluronidase degradation of five fillers of Neauvia® hydrogels line (MatexLab SA, Lugano, CH), composed of pure hyaluronic acid and based on PEGDE cross-linking (polyethylene glycol) technology that guarantees a higher biocompatibility and an optimal biointegration and rheological characteristics. The performed in vitro testing is based on the colorimetric determination of the N-acetyl-D-glucosamine (NAG) present in solution after incubation with hyaluronidase, determined at different time points in order to assess the kinetic of each product degradation (1h, 3h, 6h, 24h, 48h, 72h, 120h, and 168h). The aim of this study was to assess, in vitro, how the difference in HA content and PEGDE concentration of the analyzed fillers can influence the product biocompatibility, intended as product enzymatic clearance and duration in time. The results demonstrated that the method was reproducible and easy to perform and that all the analyzed fillers are naturally immediately available for hyaluronidase-mediated degradation.

Return to sport activities after medial displacement calcaneal osteotomy and flexor digitorum longus transfer.

PURPOSE: Medial displacement calcaneal osteotomy with flexor digitorum longus transfer is a common treatment for the management of the adult flatfoot associated with posterior tibial tendon dysfunction. In the literature, there is a paucity of information regarding the ability of patients to return to sport and recreational activities after this surgical procedure. The purpose of this retrospective clinical study was to assess the rate and type of athletic activities that patients participated in before and after medial displacement calcaneal osteotomy with flexor digitorum longus transfer. METHODS: A consecutive series of 42 patients with a mean age at surgery of 41 years (range 19-74 years) was evaluated with a minimum follow-up of 24 months (range 18-31 months). Pre- and post-operative sporting activities were assessed. At final follow-up, patients were asked to complete a Sports Athlete Foot and Ankle Score (SAFAS). Each patient was also evaluated with weight-bearing radiographs of the foot before surgery and at final follow-up. RESULTS: Preoperatively, 27 of 42 (64.3 %) patients were engaged in athletic activities, participating in an average of 1.4 h/week (range 0-6 h/week); post-operatively, 36/42 (85.7 %) participated in sport and recreational activities for an average of 3.5 h/week (range 0-15 h/week). Meary's angle improved significantly from 11.5 ± 6.2 degrees preoperatively to 7.0 ± 5.7 degrees at final follow-up (p < 0.01); calcaneal pitch improved significantly from 16.5 ± 4.6 degrees to 19.0 ± 5.0 degrees (p < 0.01). At final follow-up, patients demonstrated good SAFASs in symptom tolerance (86.4 %), pain tolerance (89.0 %), daily living performance (96.1 %), and sports performance (86.7 %). CONCLUSION: The majority of patients returned to sports and recreational activity after medial displacement calcaneal osteotomy and flexor digitorum longus for the treatment of adult flatfoot associated with posterior tibial tendon dysfunction. LEVEL OF EVIDENCE: III.

In vitro evaluation of collagen production on human fibroblasts treated with hyaluronic acid peg cross-linked with micromolecules of calcium hydroxyapatite in low concentration.

Neauvia Stimulate® is a biocompatible, injectable hyaluronic acid (HA) filler (26 mg/ml) PEG cross-linked with 1% of calcium hydroxyapatite (CaHA) for facial soft-tissue augmentation that provides volume to tissues, followed by a process of neocollagenesis for improving skin quality. The aim of the present study is to evaluate the possible modulation of collagen synthesis after treating human fibroblasts cultured in vitro with the product (Lot. 160517-26-1/2 PEG). The experimental model proposed, despite being an in vitro system, allows the derivation of useful information to predict the possible activity of the product in further in vivo application. Human fibroblasts (PEU cells) were treated with the product for 24 h at increasing concentrations of compared to control (untreated cells). The modulation of collagen synthesis was evaluated using a specific colorimetric kit (Sircol, Soluble Collagen Assay Kit). Increment of collagen production, 37.62% and 97.39% at concentrations of 1.25 mg/ml and 2.5 mg/ml of product, respectively, was considered to be statistically significant (*p values≤0.05 and **p values≤0.01) when compared with control (untreated cells). In conclusion, Hyaluronic Acid Hydrogel 26 mg/ml PEG cross-linked with calcium hydroxyapatite in low concentrations (1%) determines a statistical increment in neocollagenesis.

Radiosensitivity in lymphoblastoid cell lines derived from Shwachman-Diamond syndrome patients.

Shwachman-Diamond syndrome is an autosomal-recessive disorder characterised by bone marrow failure and a cumulative risk of progression to acute myeloid leukaemia. The Shwachman-Bodian-Diamond syndrome (SBDS) gene, the only gene known to be causative of the pathology, is involved in ribosomal biogenesis, stress responses and DNA repair, and the lack of SBDS sensitises cells to many stressors and leads to mitotic spindle destabilisation. The effect of ionising radiation on SBDS-deficient cells was investigated using immortalised lymphocytes from SDS patients in comparison with positive and negative controls in order to test whether, in response to ionising radiation exposure, any impairment in the DNA repair machinery could be observed. After irradiating cells with different doses of X-rays or gamma-rays, DNA repair kinetics and the residual damages using the alkaline COMET assay and the γ-H2AX assay were assessed, respectively. In this work, preliminary data about the comparison between ionising radiation effects in different patients-derived cells and healthy control cells are presented.

Lateral ankle and hindfoot instability: a new clinical based classification.

Ankle sprains are one of the most common soft tissue injuries accounting for nearly 40% of sports injuries. There are large number of procedures for its treatment reported in the literature with largely good results. The ankle forms a functional unit with the subtalar joint. We present a new classification for peritalar lateral instability. There are two intents of this classification. Firstly, the classification demonstrates an assessment and treatment guideline for the many causes of peritalar lateral instability. The second use of the classification is for research purposes so that cohorts of patients can be accurately described and the efficacy of different operations in different groups can be properly assessed.