Shigeo Miyazaki

Location of motoneurons in the oculomotor nucleus and the course of their axons in the oculomotor nerve

Subdivisions of the oculomotor nucleus, and the course of axons in the brainstem and more peripherally in the oculomotor nerve of the cat, were studied by directly applying horseradish peroxidase solution to the transected nerve-branch stump in the orbit. The medial rectus subdivision consisted of two subgroups, and intermingling between subdivisions was found. About 20% of the motoneurons controlling the medial rectus muscle were scattered in the medial longitudinal fasciculus or a more ventrolateral area. A few motoneurons controlling the inferior rectus or inferior oblique muscle were also located in the medial longitudinal fasciculus. Axons to the superior branch that supplied the superior rectus and levator muscle coursed in the dorsolateral half of the oculomotor nerve. In contrast, those to the medial rectus, inferior rectus, and inferior oblique muscles were scattered diffusely in the oculomotor nerve.

Cerebellar ataxia in patients with Leber's hereditary optic neuropathy

We report the cases of a mother and son with Lebers hereditary optic neuropathy (LHON), where a point mutation of mitochondria DNA from guanine to adenine on nucleotide position 11778 was verified. Both also had cerebellar ataxia and dysarthria and in both cases cerebellar atrophies were detected by computed tomography or magnetic resonance imaging. It was not possible to elucidate the relationship between LHON and the cerebellar atrophy, but it should be kept in mind that various neurological complications may occur in LHON.

Bilateral innervation of the superior oblique muscle by the trochlear nucleus

Trochlear motoneurons and their axons were labeled by applying horseradish peroxidase (HRP) solution to the transected trochlear nerve stump in the orbit of cats and rabbits. Although almost all labeled neurons were on the contralateral trochlear nucleus about 5% of them and their axons were on the ipsilateral side. These findings confirmed that the superior oblique muscle was innervated partially by a small number of ipsilateral trochlear nucleus.

Ocular complications after renal transplantation

Seventy-two post-renal transplant patients were studied for ocular complications. Of 72 patients, 56 (77.8%) showed some ocular abnormality. Steroid cataract was the most common complication, occurring in 45 patients (62.5%). Eleven patients (18 eyes) had undergone operations for cataract. The average of their ages was 39.7 years and the period from renal transplantation to cataract operation was 3.3 years. Postoperative visual acuity was over 20/20 in most cases. Increased intraocular pressure was encountered in 9 patients (12.5%), cytomegalovirus ocular infection in 2 (2.8%), hypertensive retinopathy in 2 (2.8%), branch retinal vein occlusion in 1 (1.4%), and subconjunctival hemorrhage in 15 (20.8%). A new immunosuppressant, cyclosporine, increased renal graft survival more than azathioprine. However, ocular complications such as steroid cataract occurred frequently in spite of the use of cyclosporine, as in the azathioprine era. In conclusion, it is necessary for renal transplant patients to receive a periodical ophthalmological check-up.

Optic nerve involvement in posterior paranasal sinus diseases

During a 13-year period, we encountered 18 cases of involvement by posterior paranasal sinus diseases in patients with optic neuritis. These could be divided into two groups, a mucocele and pyocele group (nine cases) and a sinusitis group (nine cases), both with the following clinical profile: The chief complaint was decreased vision, prodromal symptoms were noticed in a few cases, the visual field showing central or paracentral scotoma in almost all cases. Recurrence of visual disturbance was obscured in all patients in the mucocele and pyocele group; several cases resembled multiple sclerosis, but could be distinguished from this disease after thorough neuro-ophthalmological examination and by long-term absence of neurological signs and symptoms after nasal surgery. CSF examination showed that inflammatory changes occurred in some patients in the sinusitis group. Although there is general agreement at present that a major cause of optic neuritis is demyelination, posterior paranasal diseases should also...

Influence of visual deprivation on the visual and oculomotor system: Acetylcholinesterase activity in oculomotor neurons

The effects of visual deprivation (dark-rearing) on neurons in both the visual and oculomotor systems of black mice were studied using morphologic and histochemical techniques. In the neurons of the dorsal nucleus of the lateral geniculate body, the cytoplasm of dark-reared mice was less developed and the cytoplasm/nucleus ratio was significantly smaller in the dark-reared mice than in the controls. In contrast, large motoneurons in the oculomotor nucleus did not show any ultrastructural changes and the cytoplasm/nucleus ratio was normal. However, in large motoneurons of dark-reared mice, acetylcholinesterase (AChE)-positive areas were scattered in the cytoplasm, and the ratio of the AChE-positive areas to the cytoplasm area was significantly smaller than that in the controls.

Optic neuritis due to Aspergillus infection

A 67-year-old woman who complained of unilateral progressive visual disturbance and headache was initially diagnosed as having anterior ischemic optic neuropathy because of pale optic disc swelling and a small hemorrhage. Corticosteroid administration restored her visual acuity; however, this was only temporary and she eventually lost her vision and the headaches became severe. She died from a subarachnoid hemorrhage five months after the onset. In spite of having no remarkable problems in general condition or past history, during autopsy Aspergillus infection was unexpectedly found in the intracranial optic nerve and its surrounding tissues. Although optic nerve disturbance due to mycotic infection is rare, the latter should be considered in the etiology of optic nerve disturbances.

Analysis of Wallace mutation in patients with Leber's hereditary optic neuropathy: familial study and tissue distribution

Lebers hereditary optic neuropathy (LHON) is a disorder considered to be due to a mutation in the mitochondrial DNA (mtDNA). The authors analyzed the mtDNA genotype of peripheral blood leukocytes from two family members with LHON, and further analyzed mtDNA in various tissues originating from the separate germ layers (skin, hair, leukocyte, muscle, arachnoid, CSF cells, and buccal mucosa) in two LHON patients. A G-to-A transition of mtDNA np 11778 (Wallace mutation) was detected by the elimination of a SfaN I site and the acquisition of a Maelll site in all individuals and tissues examined.

Genetic screening of Leber’s hereditary optic neuropathy by PCR with whole blood cell lysate

Leber’s hereditary optic neuropathy (LHON) is accompanied by a mitochondrial DNA (mtDNA) mutation. The G to A substitution at nucleotide position 11,778 (11,202) of mtDNA is most common in Japanese LHON patients. Whole blood cell lysate, not purified DNA, was used as a template of the polymerase chain reaction (PCR) for the analysis of the G11,778 (11,202)A point mutation. The amplified DNA fragment was concentrated and desalted with a centrifuge device, SUPREC TM -02, and digested by SfaNI and MaeIII. This method does not need purified DNA from blood and avoids the phenol/chloroform treatments for PCR products prior to the restriction enzyme digestion. Therefore, it is convenient and safe for the genetic screening of LHON.

Re-Evaluation Of The Tonometric Sign To Detect Abnormal Blood Flow In Carotid Cavernous Fistula

The authors re-evaluated the diagnostic value of the tonometric sign in 12 cases of carotid cavernous fistula (CCF) both of the traumatic and spontaneous type. The ocular pulse amplitude was measured by indentation tonography tracings and converted to a mmHg unit. To ascertain the blood flow disparity between the paired eyes, the relative value of the ocular pulse amplitude of the affected eye to that of the fellow eye was calculated. In ten cases with unilateral CCF, the relative value ranged from 2.8 to 10.1 (average 5.1).In five cases which were successfully treated or healed spontaneously, the relative values decreased markedly and ranged from 0.8 to 1.8. Calculation of the relative value of the ocular pulse amplitude was suggested to be a sensitive and readily available method for evaluation of abnormal blood flow in CCF.