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We experienced four cases of vertical gaze palsy induced by midbrain lesions. Lesions commonly covered the rostral midbrain, including the rostral interstitial nucleus, dorsomedial to the red nucleus. Two of the four cases resulted from vascular insult, in which a single, unpaired perforator is supposed to innervate the rostral midbrain and medial thalamus bilaterally. One case showed vertical gaze palsy accompanied by bilateral ptosis. The findings agree with recent experimental evidence that a neural substrate in eyelid control lies in the supraoculomotor area immediately dorsal to the oculomotor nucleus. The remaining two cases, a brain hemorrhage and an inflammatory tumor, showed unilateral lesions of the rostral midbrain. In these cases, vertical gazes were not abolished, but were limited in an incomplete way. This may be explained by partial damages of the descending fibers, some of which decussate through the posterior commissure before it reaches the oculomotor nucleus. Thus, clinical signs and symptoms were clarified based on anatomical and physiological points of view.

Many patients suffering from episodic vertigo have no cochlear symptoms. These patients have so far been diagnosed as having Meniere's disease of the vestibular type. However, the underlying mechanisms are still to be established. In the present study, we investigated platelet aggregability in patients with dizziness, Meniere's disease, sudden deafness and facial palsy, to examine whether abnormalities in platelet aggregation is one of the causes of episodic vertigo. In 36 patients with dizziness, in 13 with Meniere's disease, in 7 sudden deafness, and in 7 facial palsy, platelet aggregability to adenosine diphosphate (ADP) was assessed by optometric technique. It was found that platelet aggregability was increased in the patients with dizziness as well as with Meniere's disease, sudden deafness and facial palsy and only the two former patient groups showed a tendency of hyperlipidemia. The administration of antiplatelet and lipidemia drugs resulted in no recurrence of vertigo during at least 3 months' follow-up. Hence, the results of our study suggest that a possible initializing factor of vertigo without cochlear symptoms might be disturbed microcirculation due to platelet hyperaggregability.

We report a patient in whom subcutaneous emphysema developed shortly after a tonsillectomy. A 55-year-old female with a chronic tonsillitis underwent a tonsillectomy, and about 8 h after surgery complained of swelling to the left side of the face and neck. There was crepitus and local tenderness in the left side of the neck. A CT scan revealed subcutaneous emphysema. The mechanisms underlying emphysema after tonsillectomy are discussed.

In this paper we report the growth of Si-doped AlGaN on an AlN/sapphire substrate by low-pressure metalorganic vapor phase epitaxy (LP-MOVPE) with an in situ monitoring system to fabricate a high-quality film with controlled thickness. The AlN mole fraction in AlGaN can be controlled by adjusting the growth temperature. We also discuss the quality and growth mechanism of AlGaN on AlN. GaN and AlGaN with an AlN mole fraction of 0.28 were free from stress because of the occurrence of three-dimensional (3D) growth. The lattice constant a of AlGaN with an AlN mole fraction of 0.40 was larger than that at an AlN mole fraction of 0.28 despite the two-dimensional (2D) growth mode. This indicates that the lattice mismatch between AlGaN and the underlying AlN adversely affects the crystal quality. AlGaN with an AlN mole fraction of over 0.60 was coherently grown on AlN owing to the fact that the AlN/sapphire template used in this work was subjected to compression. For this reason, in the samples with an AlN mole fraction of over 0.6, the crystal quality was high because of the coherent growth on the underlying AlN. Moreover, Si doping was performed for AlGaN. The carrier concentration increased linearly up to a Si concentration of 2 ×1018 cm-3, indicating that the activation rate was approximately 1.

An ultraviolet (UV)-light-source tube using a Si-doped AlGaN film as a target of electron beam excitation was fabricated. The Si-doped AlGaN was grown on an AlN/sapphire substrate by low-pressure metalorganic vapor phase epitaxy (LP-MOVPE), and its optical properties were evaluated by excitation with a 10 kV electron beam (EB). Emission intensity was significantly improved by Si doping and optimization of the growth conditions. 247 nm deep-UV light was observed from the tube, and the lifetime of the light tube until 50% emission output of the initial strength was approximately 2000 h at an EB acceleration voltage of 10 kV with a current of 100 µA.

In order to produce a streak tube operated easily, we have developed a new streak tube having ultra-high deflection sensitivity based on a new design concept. Both the low photocathode voltage of -2 kV referred to the anode and the long deflection plate of 63 mm made it possible to achieve the deflection sensitivity of 670 mm/kV. Furthermore, the temporal resolution of 2 ps was achieved by applying a high electric field of 2 kV/mm between the photocathode and the acceleration mesh electrode.

The nucleus of the optic tract (NOT) has been identified as the link between the retina and the premotor nuclei in the pathway mediating the optokinetic nystagmus (OKN). However, it is still unclear from what parts of the retina and what kinds of retinal ganglion cells the NOT receives visual inputs related to OKN. In the present study, horseradish peroxidase conjugated with wheatgerm agglutinin (WGA-HRP) was injected into the NOT of hooded rats to investigate retrogradely labeled cells in the retina. A solution of WGA-HRP was injected into the NOT through a glass micropipette. Injection sites of the brain and the retina were processed by tetramethyl benzidine protocol and Hanker-Yates method. The labeled cells were observed in the whole area of the retina contralateral to the injection site, while located only in the ventral region of the retina ipsilateral to the injection site. In the retina contralateral to the injection site, a large number of small-sized cells and a few medium-sized cells were labeled diffusely except for surroundings of the optic disc, whereas in the ipsilateral retina there were small and medium-sized cells in the ventral part, being about 8 times greater than those in the contralateral retina. The present study indicates that visual signals responsible for OKN are conducted through the retinal ganglion cells mainly contralaterally, and only from the ventral area of the retina ipsilateral to the injection site.

Four stereoisomers of oxy-peptide nucleic acids containing ether linkages in the main chain and conformationally-restricted pyrrolidine rings (pyrrolidine-based oxy-PNA = POPNA) were newly synthesized and investigated for binding to DNA. cis-L-POPNA with 9 adenine bases formed the most stable hybrid with dT9. The POPNA showed high sequence specificity similar to that of the Nielsen-type PNA and sharper melting behavior in hybridization with DNA than the Nielsen-type PNA.

We report here a rare case of vertical nystagmus, dysarthria and broad-based gait due to after-effects of lithium intoxication.A 65-year-old man was admitted with dysarthria and gait disturbance. About 14 years ago, he had begun treatment with lithium carbonate for manic psychosis. Ten years ago, he developed dysarthria and a broad-based gait due to lithium intoxication.Neuro-otological examination demonstrated, downbeat nystagmus in the primary position, rebound nystagmus and direction changingopposing vertical positioning nystagmus.Failure of fixation-suppression of caloric nystagmus was noted in both sides. Eye-tracking test revealed saccadic eye movements, and slow phase OKN velocity was limited billaterally. The equilibrium disturbances observed in this patient's neurological and ENG findings might be attributed to pathological conditions of cerebellar vermis, flocculus and partly brainstem.He was treated with thyroid stimulating hormone (2mg/day) for 18 days.Thereafter, gradually he recovered from some of his neurological symptoms : dysarthria, gait disturbance, rebound nystagmus and direction changing opposing vertical positioning nystagmus.His vertical nystagmus, however, remained unchanged.

Recent neurophysiological studies have disclosed that the nucleus of the optic tract (NOT) in the pretectum is the first relay station responsible for horizontal optokinetic nystagmus (OKN) both in non-foveate and foveate animals. However, what parts of the retina and what kinds of retinal ganglion cells project their fibers into the NOT have been controversial. In the present study, horseradish peroxidase conjugated with wheatgerm agglutinin (WGA-HRP) was injected into the NOT of rats. The retina and injection sites were processed for the histochemical demonstration of WGA-HRP in order to investigate the distribution of the retinal ganglion cells projecting into the NOT. The present study indicated that visual signals responsible for OKN are mainly conducted from the contralateral retinal ganglion cells, and only from the ventral area of the ipsilateral retina. The retinal ganglion cells projecting into the NOT ipsilateral to the injection site were larger than those on the contralateral side. Large retinal ganglion cells existed on the peripheral areas including ipsilateral ventral area. The density of the ventral ganglion cells of the retina contralateral to the injection site was lower than that in other areas of retina, and the density of the ventral ganglion cells ipsilateral to the injection site tented to be greater than that on the contralateral side. Since the ventral area of retina corresponded to the upper visual field in front of the nose, it may receive visual signal of OKN and fire OKN. In conclusion, visual signals responsible for OKN are conducted through the retinal ganglion cells mainly contralaterally, and only from the ventral area of the retina ipsilateral to the injection site.