Keiichi Ikeno

The Mechanism of Irritative Nystagmus and Paralytic Nystagmus: A Histochemical Study of the Guinea Pig's Vestibular Organ and an Autoradiographic Study of the Vestibular Nuclei

To establish the difference of mechanism between irritative and paralytic nystagmus, alterations of Na-K-ATPase and succinic dehydrogenase activity in the vestibular sensorineural elements were investigated for 20 guinea pigs, and glucose uptake of the vestibular nuclei for 13 guinea pigs were measured by the [14C]-2-deoxy-D-glucose method. Irritative and paralytic nystagmus were experimentally provoked by introducing K+ into the perilymphatic space. From the results it was concluded that irritative nystagmus is provoked by increased excitability of vestibular sensory cells, while paralytic nystagmus is provoked by decreased excitability. However, the direction of nystagmus was eventually decided by the tonus imbalance between the bilateral vestibular nuclei. The ipsilateral vestibular nucleus was predominant during irritative nystagmus, while the contralateral vestibular nucleus was predominant during paralytic nystagmus.

Therapeutic and Prophylactic Effect of Triludan on Japanese Cedar Pollinosis.

Triludan® was administered to 75 patients with Japanese cedar pollinosis to determine its effectiveness and safety. Triludan® was effective not only in patients who started using it before the beginning of the pollen season, but also in those who began taking it after the season had started. The drug was most effective for “sneezing” and “rhinorrhea”, but “nasal obstruction” was not so markedly improved. Side effects were reported by six patients (7.9%), three of whom complained of drowsiness.

An Experimental Study on the Mechanism of the Ménière’s Attack: The Influence of High Perilymphatic Potassium Concentration on the Vestibular System

Clinical characteristics of Meniere’s disease are episodic vertigo and fluctuating hearing loss, the origin of which is still obscure. It is well known that nystagmus is always present during the attack, as described by Aschan and Stahle [1], but whose character is not always the same. According to a previous study [2], irritative, paralytic, and reversal nystagmus were observed during the Meniere’s attack in 25%, 36%, and 39% of patients, respectively. To explain such complicated clinical manifestations, Schuknecht’s membrane rupture theory [3] would be most acceptable. He ascribed the episodic vertigo and fluctuating hearing loss to the rupture and repairing process in the endolymphatic system. His findings were supported by Silverstein [4], who provoked nystagmus by perfusing the perilymphatic space with artificial endolymph. Silverstein thought that sensorineural excitability might be altered by high perilymphatic potassium concentration. Dohlman [5] theorized that, on the basis of the membrane rupture theory, an initial ipsilateral nystagmus could occur due to partial depolarization of the vestibular nerve by the leaking endolymph, and then as the depolarization became more complete, the direction of nystagmus would turn to the contralateral side. Molinari [6] considered that the irritative nystagmus was due to the excitation of the vestibular receptor cells, and that the paralytic nystagmus was due to the inhibitory rebound in the central nervous system. Meissner [7] speculated that the potassium concentration in perilymph determined the extent of depolarization of the sensorineural synpase and brought about the tonus imbalance of the vestibular nuclei followed by ipsior contralateral nystagmus.

Clinical evaluation of azelastin hydrochloride in the treatment of perennial allergic rhinitis.

The incidence of allergic rhinitis has been increasing, and more drugs have been developed to treat it.A clinical trial was carried out on 173 patients with perennial allergic rhinitis to determine the efficacy and safety of azelastine hydrochloride, which inhibits neurotransmitter activity, especially leukotriene production and release and histamine release. It is as effective as disodium cromoglicate (DSCG) when administered orally in a single dose of 1mg.Sugarcoated tablets of azelastine hydrochloride were administered to patients with allergic rhinitis in a dose of 1mg twice daily, in the morning and at bedtime, for 4 weeks.1) Subjective symptoms (sneezing, nasal discharge, nasal obstruction and disturbed ADL) and subjective symptoms (volume of nasal discharge, swelling of the mucous membrane of the inferior concha, and eosinophilia in the nasal discharge) were significantly improved by both 2 and 4 weeks of treatment.2) General improvement (moderate or greater) was 31.2% after 2 weeks of treatment and 56.6% at 4 weeks.3) The stratified general improvement rating was significantly higher in patients with severe symptoms than in those with moderate symptoms.4) Side effects were observed in 6 patients, 3 of whom had drowsiness, 2 neutrophilia and 1 drug eruption. None of the side effects were serious however.Those azelastine hydrochloride appears to be a drug of high efficacy and safety in the treatment of perennial allergic rhinitis.