High intensity light emitting diodes (LEDs) are being studied as possible light sources for the phototherapy of neonatal jaundice, as they can emit high intensity light of narrow wavelength band in the blue region of the visible light spectrum corresponding to the spectrum of maximal bilirubin absorption. We developed a prototype blue gallium nitride LED phototherapy unit with high intensity, and compared its efficacy to commercially used halogen quartz phototherapy device by measuring both in vitro and in vivo bilirubin photodegradation. The prototype device with two focused arrays, each with 500 blue LEDs, generated greater irradiance than the conventional device tested. The LED device showed a significantly higher efficacy of bilirubin photodegradation than the conventional phototherapy in both in vitro experiment using microhematocrit tubes (44 +/-7% vs. 35 +/-2%) and in vivo experiment using Gunn rats (30 +/-9% vs. 16 +/-8%). We conclude that high intensity blue LED device was much more effective than conventional phototherapy of both in vitro and in vivo bilirubin photodegradation. Further studies will be necessary to prove its clinical efficacy.
Animals ; Bilirubin/*metabolism ; Biochemistry/*methods ; Gallium/pharmacology ; Hematocrit ; In Vitro ; *Light ; Phototherapy/*methods ; Rats ; Rats, Gunn ; Research Support, Non-U.S. Gov't

OBJECTIVETo investigate the effect of organic gallium and gallium chloride on bone metabolism and their therapeutic effect against tretinoin-induced osteoporosis in rats.

METHODSRat models of osteoporosis was established with intragastric administration of tretinoin at the daily dose of 85 mg/kg for 15 days and randomized into control, organic gallium and gallium chloride groups. After administration of the corresponding treatments (none for the control group) for 4 weeks, the changes of the indices for osteoporosis were evaluated through biochemical and pathological approaches.

RESULTSTretinoin induced obvious changes in bone structure and contents of bone calcium and other elements, causing also significantly increased tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (AKP), which suggested the development of osteoporosis. Administration of organic gallium and gallium chloride treatments increased the bone density, bone cortex thickness and the percentage of bone trabecula, and Ga, Ca, P contents in the femur and teeth, but lowered the activity of TRAP and AKP, suggesting decreased bone conversion rate. Compared with gallium chloride, organic gallium required smaller dose with better safety to produce better therapeutic effect.

CONCLUSIONOrganic gallium can be safe and effective for treatment of tretinoin-induced osteoporosis in rats.

Animals ; Cell Line, Tumor ; Female ; Femur ; drug effects ; metabolism ; pathology ; Gallium ; chemistry ; pharmacology ; therapeutic use ; Hemodynamics ; drug effects ; Organometallic Compounds ; chemistry ; pharmacology ; therapeutic use ; Osteoporosis ; chemically induced ; drug therapy ; metabolism ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Tooth ; drug effects ; metabolism ; Trace Elements ; metabolism ; Tretinoin ; pharmacology