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[1] Sprites are a spectacular type of transient luminous events which occur above thunderstorms immediately after lightning. They have shapes of giant jellyfish, carrots, or columns and last tens of milliseconds. In Earth's atmosphere, sprites mostly emit in red and blue wavelengths from excited N 2 and N 2 + and span a vertical range between 50 and 90 km above the surface. The emission spectra, morphology, and occurrence heights of sprites reflect the properties of the planetary atmosphere they inhabit and are related to the intensity of the initiating parent lightning. This paper presents results of theoretical calculations of the expected occurrence heights of sprites above lightning discharges in the CO 2 atmosphere of Venus, the N 2 atmosphere of Titan, and the H 2 -He atmosphere of Jupiter. The expected emission features are presented, and the potential of detecting sprites in planetary atmospheres by orbiting spacecraft is discussed.

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The observation of winter lightning has been continued using magnetic links, digital recording systems for the current oscillograms, field mills, still cameras and video camera systems for the images of lightning channels on the west coast of Japan. Of the 59 magnetic link records, 59% were negative in polarity, 29% were positive, and the remaining 12% were unknown. The maximum peak current was over 270 kA in a positive flash, and the largest peak currents were found in positive flashes. The measured current oscillograms show that winter lightning stroke or ground flash often has a very long duration or continuing current. Moreover, two kinds of bipolar strokes were frequently recorded in the winter season. Nine of the 45 flashes showed bipolar strokes, 24 flashes were negative in polarity, seven were positive, and five were unknown.

A 34-year-old man with a 1-week history of diplopia was referred to the authors' hospital. Neurological examination revealed left abducens nerve palsy. Computed tomography showed a lesion in the left sphenoid sinus involving the medial wall of the left internal carotid artery (ICA) and osteolytic change at the clivus bordering the lesion. Magnetic resonance imaging demonstrated an extensive soft-tissue mass occupying the left sphenoid sinus. Surgical intervention by the endoscopic transnasal method allowed most of the lesion to be removed. Only the portion attached to the medial wall of the ICA was not removed. Postoperatively, the lesion was diagnosed as a giant cell tumor (GCT) and the patient received 120 mg of subcutaneous denosumab every 4 weeks, with additional doses on Days 8 and 15 during the first month of therapy. MRI a week after starting denosumab revealed shrinkage of the initially fast-growing residual tumor. The patient was discharged upon completion of the third denosumab administration. GCT is an aggressive stromal tumor developing mainly in young adults. Complete resection is recommended for GCT in the literature. However, size and location of the CGT often limit this approach. Various adjuvant treatments for skull base GCTs have been reported, including radiation and chemotherapy. However, the roles of adjuvant therapies have yet to be clearly defined. Denosumab, a monoclonal antibody, was recently approved for GCT in several countries. Denosumab may permit less invasive treatments for patients with GCTs while avoiding deleterious outcomes, and may also limit disease progression and recurrence.

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