Biological evaluation of intervertebral disc cells in different formulations of gellan gum‐based hydrogels

Gellan gum (GG)‐based hydrogels are advantageous in tissue engineering not only due to their ability to retain large quantities of water and provide a similar environment to that of natural extracellular matrix (ECM), but also because they can gelify in situ in seconds. Their mechanical properties can be fine‐tuned to mimic natural tissues such as the nucleus pulposus (NP). This study produced different formulations of GG hydrogels by mixing varying amounts of methacrylated (GG‐MA) and high‐acyl gellan gums (HA‐GG) for applications as acellular and cellular NP substitutes. The hydrogels were physicochemically characterized by dynamic mechanical analysis. Degradation and swelling abilities were assessed by soaking in a phosphate buffered saline solution for up to 170 h. Results showed that as HA‐GG content increased, the modulus of the hydrogels decreased. Moreover, increases in HA‐GG content induced greater weight loss in the GG‐MA/HA‐GG formulation compared to GG‐MA hydrogel. Potential cytotoxicity of the hydrogel was assessed by culturing rabbit NP cells up to 7 days. An MTS assay was performed by seeding rabbit NP cells onto the surface of 3D hydrogel disc formulations. Viability of rabbit NP cells encapsulated within the different hydrogel formulations was also evaluated by Calcein‐AM and ATP assays. Results showed that tunable GG‐MA/HA‐GG hydrogels were non‐cytotoxic and supported viability of rabbit NP cells. Copyright © 2012 John Wiley & Sons, Ltd.     

Effects of dexpanthenol with or without Aloe vera extract on radiation-induced oral mucositis: Preclinical studies

Purpose: To define the effect of dexpanthenol with or without Aloe vera extract on radiation-induced oral mucositis.

Materials and methods: Mouse tongue mucosal ulceration was analysed as the clinically relevant endpoint. Graded single or fractionated dose irradiation (10 x 3?Gy/2 weeks, graded test doses on day 14) were combined with topical administration of dexpanthenol or a base, with or without Aloe vera extract. The formulations were applied for 14 days (single dose) or 24 days after the first fraction.

Results: Single dose irradiation resulted in an ED₅₀ (dose at which a positive mucosal response was expected in 50% of the animals irradiated) of 11.9?±?1.2?Gy. None of the formulations yielded a significant change in incidence or time course of ulceration. Test irradiation after 10 x 3?Gy gave an ED₅₀ of 9.0?±?0.1?Gy. Base treatment increased the ED₅₀-values to 10.5?±?0.8?Gy (p?=?0.0095) and 9.9?±?0.7?Gy (p?=?0.0445) without or with Aloe vera. Dexpanthenol resulted in ED₅₀ values of 9.5?±?0.1?Gy without Aloe vera (p?>?0.05), and of 10.9?±?0.9?Gy (p?=?0.0035) with Aloe vera. The latent time to ulceration was prolonged, compared to the control (6.3 days) without Aloe vera (8.0?–?8.2 days, p?<?0.001) and with dexpanthenol and Aloe vera (7.3 days, p?=?0.0239).

Conclusions: With single dose irradiation, neither dexpanthenol nor Aloe vera extract significantly changed the oral mucosal radiation response. With fractionated irradiation, drug administration significantly increased the isoeffective radiation doses, independent of dexpanthenol or Aloe vera content. Neither dexpanthenol nor Aloe vera display a prophylactic potential.     

X-linked hypophosphatemia in adults: prevalence of skeletal radiographic and scintigraphic features

The radiologic studies of 38 essentially untreated adults with X-linked hypophosphatemia (XLH) were reviewed to determine the prevalence of radiologic features, to compare the findings in men and in women, and to elucidate the natural history of the disease by comparing the findings in young, intermediate-age, and older patients. Bone-reinforcement lines were common, but no characteristic mineral mass alteration was established. Looser zones were more prevalent in older subjects. Osteoarthritis was common, occurring in the ankles, knees, feet, sacroiliac joints, and wrists. Enthesopathy was infrequent in the younger group but was present in every member of the intermediate and older groups and was often accompanied by extra ossicles. Curvatures of the lower-extremity long bones were common in all age groups. Three new skeletal alterations in XLH were found to be common: flaring of the iliac wings, trapezoidal distal femoral condyles, and alterations in talar morphology, including shortening of the talar neck and flattening of the talar dome. Technetium-99m methylene diphosphonate scintigrams of 17 subjects were often abnormal, depicting bowing deformity and focal tracer accumulation in diaphyseal cortices and in periarticular and extraarticular regions. The mean metabolic index was moderately elevated (4.0). Both radiographic and scintigraphic findings were more severe in men, consistent with hemizygosity. The natural history of untreated XLH in both sexes is characterized by the development of a variety of age-related skeletal abnormalities during adulthood.