Evaluation of a Ultraviolet B Light Emitting Diode (LED) for Producing Vitamin D3 in Human Skin.

AIM: A commercially available light emitting diode (LED) that transmitted narrow band ultraviolet B (UVB) radiation was evaluated for its efficacy and efficiency to produce vitamin D3 in human skin. MATERIALS AND METHODS: Human skin samples were obtained from surgical procedures. The LED had peak emission wavelength of 295 nm. Skin samples were exposed to the UVB-LED for varying times and then were analyzed by high-pressure liquid chromatography (HPLC) to determine the vitamin D3 content. RESULTS: There was a statistically significant time- and dose-dependent increase in the percent of 7-dehydrocholesterol that was converted to vitamin D3 in the skin type II samples; 1.3%±0.5, 2.3%±0.6 and 4.5%±1.67 after exposure to 0.75 (11.7 mJ/cm2), 1.5 (23.4 mJ/cm2) and 3 (46.8 mJ/cm2) minimal erythemal doses (MEDs), respectively. CONCLUSION: The UVB-LED was effective and efficient in generating vitamin D3 in human skin, in vitro. The amount of vitamin D3 production increased in a dose-dependent fashion with increased UVB energy. UVB-LEDs can be developed for devices that can efficiently produce vitamin D3 in human skin.

Toe flexors strength and passive extension range of motion of the first metatarsophalangeal joint in individuals with plantar fasciitis.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To determine if a difference exists in toe flexors strength and passive extension range of motion of the first metatarsophalangeal joint between individuals with unilateral plantar fasciitis and control subjects. BACKGROUND: Weakness of the dynamic longitudinal arch supporters and shortening of the plantar fascia have been suggested as etiologic factors for plantar fasciitis. METHOD AND MEASURES: Twenty subjects with unilateral plantar fasciitis participated in the study. Subjects had had symptoms for an average (+/-SD) of 19.9 +/- 33.2 months prior to participating in the study. Twenty control subjects matched for sex and age were also tested. Each subject was measured bilaterally for passive extension range of motion of the first metatarsophalangeal joint and peak resistance force observed during an isometric test of toe flexors strength. RESULTS: Subjects with unilateral plantar fasciitis demonstrated weaker toe flexors (P<.05) than the control subjects. A significant main effect for feet also indicated that the toe flexors for the involved feet were significantly weaker than the uninvolved feet (P<.05) of subjects with unilateral plantar fasciitis. Passive extension range of motion of the first metatarsophalangeal joint was not significantly different between the involved and the uninvolved feet for subjects with plantar fasciitis. CONCLUSION: Results for our subjects indicate that the extensibility of soft tissues influencing extension of the first metatarsophalangeal joint was not related to the presence of plantar fasciitis. Additional research is needed to determine if toe flexors weakness is a cause or a result of plantar fasciitis and if strengthening regimes for the toe flexors are effective interventions for plantar fasciitis.