CONTACT PHOTOALLERGY TO TRIBROMSALICYLANILIDE
SUMMARY. .
The nature of tribromosalicylanilide photoallergy.
Three patients with photoallergy to 3,4',5 tribromosalicylanilide (TBS) following the use of a germicidal soap were studies to determine the mechanism of their photoallergy. None of these subjects had undergone previous patch or photopatch testing. Duplicate patches of purified TBS and its photoproducts 4', 5 dibromosalicylanilide (DBS). 4' monobromosalicylanilide (MBS), and salicylanilide were applied to the skin of the back. One set of patches was irradiated using a source of long ultravoilet whereas all ultraviolet radiation was regorously excluded from the second set. In one patient the results were consistent with a plain contact allergy to the photoproducts DBS and MBS. In a second patient irradiation of any of the three brominated salicylanilides resulted in a reaction whereas no reactions were observed in the dark. A free radical mechanism may be responsible for the formation of the complete antigen in this patient. In the third patient both mechanisms appeared to coexist. Reactions to commercial-grade TBS did not differ from those obtained with pure TBS.
Properties of a monopivot centrifugal blood pump manufactured by 3D printing
An impeller the same geometry as the impeller of a commercial monopivot cardiopulmonary bypass pump was manufactured using 3D printing. The 3D-printed impeller was integrated into the pump casing of the commercially available pump to form a 3D-printed pump model. The surface roughness of the impeller, the hydraulic performance, the axial displacement of the rotating impeller, and the hemolytic properties of the 3D-printed model were measured and compared with those of the commercially available model. Although the surface roughness of the 3D-printed model was significantly larger than that of the commercially available model, the hydraulic performance of the two models almost coincided. The hemolysis level of the 3D-printed model roughly coincided with that of the commercially available model under low-pressure head conditions, but increased greatly under high-pressure head conditions, as a result of the narrow gap between the rotating impeller and the pump casing. The gap became narrow under high-pressure head conditions, because the axial thrust applied to the impeller increased with increasing impeller rotational speed. Moreover, the axial displacement of the rotating impeller was twice that of the commercially available model, confirming that the elastic deformation of the 3D-printed impeller was larger than that of the commercially available impeller. These results suggest that trial models manufactured by 3D printing can reproduce the hydraulic performance of the commercial product. However, both the surface roughness and the deformation of the trial models must be considered to precisely evaluate the hemolytic properties of the model.