Objective: Plasma cluster ions consist of positive and negative ions and are known to suppress the activity of total bacteria, mold fungi, viruses and allergens floating in the air. In terms of inactivating mite allergens, it was reported that plasma cluster ions suppressed the symptoms of atopic dermatitis in mice. In the present study we investigated the effect of plasma cluster ions on attenuating chronic allergic rhinitis and fatigue induced by mite allergens in humans.
Design: Sixteen subjects with specific immunoglobulin E (IgE) positive to Dermatophagoides pteronyssinus, who had symptoms of allergic rhinitis caused by house dust participated in a randomized double-blinded crossover trial. Subjects occupied a mite allergen challenge room and performed mental task for 4 hours with 25,000/cm³ plasma cluster ions or without plasma cluster ions and rested for 2 hours outside of the room. We measured mite allergens (Der p1) on the floor using plastic dishes (90 mm diameter) placed at 5 points in the room. We also investigated the symptoms of allergic rhinitis using the Japanese Allergic Rhinitis Standard QOL Questionnaire (JRQLQ) during the 4-hour load and 2-hour rest and performance by Uchida-Kraepelin psychodiagnostic test during the 4-hour load.
Result: Plasma cluster ions inactivated 80–90% of Der p1 and attenuated the symptoms of nasal congestion in JRQLQ. Moreover, plasma cluster ions inhibited fatigue-induced impaired performance in Uchida-Kraepelin psychodiagnostic test compared to the case without the ions.
Conclusion: Plasma cluster ions reduce mite allergens and are effective for attenuating chronic allergic rhinitis and fatigue.

We report a case of primary intracranial malignant melanoma (PIMM) with extracranial metastases. The patient was an 82-year-old woman diagnosed with PIMM under the left cerebellar tentorium. We performed a tumor resection followed by gamma knife surgery. An magnetic resonance imaging at 11 months after surgery showed a local intracranial recurrence. At 12 months, vertebral metastasis was suspected, and 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) showed multiple extracranial metastases. She died at 13 months after surgery. Although extracranial metastases of PIMM are extremely rare, we should carefully follow up extracranial metastases together with intracranial ones, especially by FDG-PET/CT, even at an early asymptomatic stage.
Aged, 80 and over ; Electrons ; Female ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Melanoma* ; Neoplasm Metastasis* ; Positron-Emission Tomography ; Recurrence