The Use of a Metal Halide Lamp for the Induction of Photohemolysis in Porphyria

Abstract

Several light sources, including sunlight, xenon lamps, fluorescent lamps, mercury lamps and carbon arc lamps, have been used to provoke skin changes for phototests in patients with porphyrias, or to induce experimental hemolysis of porphyrins for research. The metal halide lamp has a strong emission range between 400 nm and 450 nm, and a relatively low emission range in the ultraviolet region. For this reason, we explored the possibility that this lamp could be used to induce photohemolysis caused by hematoporphyrin (HP) and the radiation of light. Twenty to forty μg of HP‐HCl was added to 25 ml of a normal red blood cell suspension. The flask containing this red blood cell suspension was then irradiated using a metal halide lamp with 3.6 to 10.8 J/cm2 of light. All of the irradiated red blood cell suspension was hemolyzed, but the non‐irradiated control showed very little hemolysis. Compared to natural sunlight, the energy emitted by the metal halide lamp is small. Therefore, a longer exposure from the metal halide lamp is required to obtain an amount of energy equivalent to sunlight. This type of light source covers a wide area for irradiation. From these results, we can speculate that a metal halide lamp source is of value when used experimentally to produce the chronic skin changes of porphyria.

Induction of Chronic Skin Changes in Intraperitoneally Hematoporphyrin‐Injected Mice with Metal Halide Lamp Irradiation

“…An adequate artificial light source is necessary to achieve consistency. As speculated in previous reports (6), the MH lamp has many 'advantages, because it induces chronic skin changes in the animal model. An induction of experimental porphyria due to GF and HCB is utilized for the investigation of porphyric photosensitivity.…”

“…Immunofluorescent studies were performed in 16 mice. Definite linear deposition of IgG in the dermo-epidermal junction was seen in all mice, but the deposition of IgM was seen in only 6 mice and IgA in only 2. Granular deposition of C3 was seen in the dermoepidermal junction of 5 mice.…”

“…A 700W metal halide (MH) lamp (Mitsubishi, M-700 G-D, Stabilizer: HGN 700 HA-lOO) was used in this study. The spectral irradiance and intensity of the energy in this lamp have been described in a previous report (6). The mice were irradiated for 2 hours (7.2 j/cm Z ) twice a week using a glass filter (5 mm thickness) to avoid UVB; treatment started 30 minutes after the intraperitoneal injection.…”

“…We showed that a metal halide lamp source could induce photohemolysis of red blood cells treated with hematoporphyrin, and of red blood cells in mice with griseofulvin-induced protoporphyria (6). We speculated that this source can induce changes similar to the chronic ones in porphyria.…”

Inhibitory Effect of Rumex Japonicus Houtt on the Porphyrin Photooxidative Reaction

“…The absorbance of the supernatant at 540 nm was measured using a spectrophotometer (Hitachi U-1500, Tokyo,Japan). The rate of hemolysis was calculated by Honda's method (14).…”