Broadband UVB (broadband + uvb)

Distribution by Scientific Domains

Selected Abstracts

AlamarBlue bioassay for cellular investigation of UV-induced crystalline lens damage

Olanrewaju M. Oriowo
Abstract Purpose: The use of the alamarBlue fluorescence dye for cellular study of UV-induced photodamage in cultured ocular lenses was examined by comparing the results from the fluorometric assay to lens optical quality using a scanning laser system to measure the focal lengths of the lenses following UVB treatment. Methods: Excised porcine lenses were cultured in M199 supplemented with 1% antibiotics and 4% porcine serum. After 1 week of pre-incubation at 37C, baseline measurements were taken. Treated lenses were irradiated with a range of UVB radiant exposures from 0.019 to 0.076 J cm,2. The lenses were maintained for a further 4 weeks, with measurements carried out every 48 h in the first 9 days post-UVB treatment and then once each week. At each measurement session, treated and control lenses were transferred into a 24-well plate, one lens per well containing the assay. The lenses were incubated for 50 min, after which fluorescence readings were taken with a plate reader. Results: Analyses showed significant (p < 0.05) inhibition of lens metabolic activity and optical function in the 0.038 and 0.076 J cm,2 UVB treated lenses. Lenses treated with 0.019 J cm,2 UVB did not exhibit any photodamage. Conclusions: These results suggest that the alamarBlue assay is useful for the in vitro study of UV-induced lens damage. The decrease in the capacity of treated lenses to reduce alamarBlue over time confirms that UVB photo-oxidation can cause diminution of viable lens epithelial and fibre cells. The results also suggest that the energy threshold for broadband UVB induced cataractogenesis in vitro ranges between 0.019 and 0.038 J cm,2. [source]

Vitamin D production in psoriasis patients increases less with narrowband than with broadband ultraviolet B phototherapy

Amra Osmancevic
Background: Phototherapy of psoriasis is an effective treatment. In addition to standard broadband ultraviolet radiation B (UVB), (280,320 nm), narrowband phototherapy (NBUVB) (monochromatic UV between 311 and 312 nm) has become an important treatment for psoriasis. The same wavelength range of UVB (290,315 nm) induces synthesis of vitamin D. The aim was to compare the effect of broadband with NBUVB therapy on vitamin D synthesis in patients with psoriasis. Methods: Sixty-eight Caucasian patients (17 women and 51 men) mean age 54.1 16.0 years, with active plaque psoriasis, were treated with broadband UVB (n=26) or NBUVB (n=42) two to three times/week for 8,12 weeks. The serum concentrations of 25-hydroxyvitamin D (25(OH)D3), 1,25-dihydroxyvitamin D (1,25(OH)2D3), intact parathyroid hormone (PTH), calcium and creatinine were measured before the first exposure and after the last dose of radiation. Results: In broadband UVB treated patients, 25(OH)D3 increased from 37.9 16.9 to 69.4 19.7 ng/ml (P<0.0001) and in patients treated with NBUVB from 34.8 11.9 to 55.3 17.6 ng/ml (P<0.0001) and P=0.008 between the treatment groups. PTH decreased on broadband UVB (P<0.05). The serum concentrations of 1,25(OH)2D3, calcium or creatinine remained unaltered. Conclusion: Serum 25(OH)D3 in psoriasis patients increased less with NBUVB than with broadband UVB phototherapy. Psoriasis improved on both regimens. [source]

Evaluating the cytotoxic doses of narrowband and broadband UVB in human keratinocytes, melanocytes, and fibroblasts

Tae-Ho Cho
Summary Background: No comparative and simultaneous in vitro studies have been performed to determine the cytotoxic dose of narrowband UVB (NBUVB) and broadband UVB (BBUVB) for keratinocytes, melanocytes, and fibroblasts. Culture medium was often replaced with phosphate-buffered saline (PBS) before UV irradiation; however, its amount differed across studies. We determined the cytotoxic doses of NBUVB and BBUVB and tested for changes in viability according to the amount of PBS. Methods: We exposed cultured human keratinocytes, melanocytes, and fibroblasts to ultraviolet light in the range 12.5,1000 mJ/cm2 for NBUVB and 1.25,100 mJ/cm2 for BBUVB. The viability was assessed after 24 h. We also determined changes in viability at cytotoxic doses according to the amount of PBS (40, 80, and 120 ,l/well in a 96-well plate). Results: Cytotoxicity was observed at doses of 100, 200, and 400 mJ/cm2 for NBUVB and 5, 10, and 25 mJ/cm2 for BBUVB in keratinocytes, melanocytes, and fibroblasts, respectively. At cytotoxic doses, there was no change in viability according to the amount of PBS. Conclusions: Fibroblasts are more resistant to UVB irradiation, irrespective of the amount of NBUVB and BBUVB, than keratinocytes and melanocytes. The amount of PBS during irradiation had no effect on viability. [source]

Comparison of broadband UVB, narrowband UVB, broadband UVA and UVA1 on activation of apoptotic pathways in human peripheral blood mononuclear cells

Chanisada Tuchinda
Background/purpose: Ultraviolet (UV) radiation is an important therapy for immune-mediated cutaneous diseases. Activation of early apoptotic pathways may play a role in the clinical effectiveness. Different UV wavelengths have different efficacy for various diseases, but it remains unclear whether the ability to induce apoptosis differs with respect to the wavelength, and whether they induce apoptosis through the same mechanism. The aim of this study is to analyze the effects of different UV wavelengths that are used clinically on normal human peripheral blood mononuclear cells (PBMCs). Methods: PBMCs were treated with UV-light sources broadband UVB, narrowband UVB, broadband UVA and UVA1. Initiation of apoptosis was assessed by flow cytometry by staining,treated cells for activated caspases. Immunoblots were performed to measure for cleaved caspase-3, -8, -9, cytochrome c, Bcl 2-interacting domain and poly-(ADP ribose) polymerase cleavage. Results: We demonstrate that all the UV radiation sources induced caspase activation in a dose-and time-dependent manner. Components of both the extrinsic and intrinsic pathways of apoptosis were activated by all of the UV wavelengths tested, but differed in the level of energy needed for activation. Conclusion: The greater effectiveness of UVB on initiation of apoptotic pathway suggests that apoptosis may play a role in the clinical efficacy of UVB-responsive inflammatory cutaneous diseases. [source]

The effect of narrowband ultraviolet B on the expression of matrix metalloproteinase-1, transforming growth factor-,1 and type I collagen in human skin fibroblasts

C. P. Choi
Summary Background., Ultraviolet (UV) irradiation induces chronic skin diseases, such as skin cancer and photoageing, and the mechanisms of this skin damage are associated with the upregulation of matrix metalloproteinases (MMPs) and decreased collagen synthesis. Narrowband ultraviolet B (NB-UVB) radiation is a relatively new treatment modality for vitiligo and psoriasis. However, the mechanism of NB-UVB action on photoageing is not completely understood. Aims., We investigated the effects of NB-UVB on the expression of MMP-1, transforming growth factor (TGF)-,1 and type I collagen in cultured human skin fibroblasts. Methods., Cultured human fibroblasts were irradiated with either NB-UVB (50,800 mJ/cm2) or broadband UVB (BB-UVB; 25 mJ/cm2). The expression of MMP-1, TGF-,1 and type I collagen mRNA was determined by reverse-transcription PCR. Expression of MMP-1 and TGF-,1 protein was determined by ELISA and that of type I collagen by Western blotting. Results., NB-UVB induced the expression of MMP-1 and reduced the expression of TGF-,1 and type I collagen at the mRNA and protein levels in a dose-dependent manner. The expression of type I collagen protein decreased more after irradiation with 25 mJ/cm2 of BB-UVB than 400 mJ/cm2 of NB-UVB. Conclusions., This study indicates that NB-UVB irradiation reduces type I collagen synthesis in human skin fibroblasts by inhibiting TGF-,1 expression and stimulating the release of MMP-1. It also suggested that the photoageing-related effects of NB-UVB are weaker than those of BB-UVB in vitro. [source]