Kenichi Tanimura

Microelectrode study on the subnuclei of the oculomotor nucleus in the cat

Abstract The oculomotor nucleus of the cat was investigated by means of the marking microelectrode technique. By antidromic spike response to stimulation of the respective oculomotor nerve branch, inferior rectus, medial rectus, superior rectus and inferior oblique neurons were identified, and their locations were determined histologically. (1) The antidromic spike latency of 27 inferior rectus units was between 0.4 and 3.0 msec, and the conduction velocity calculated on this group was between 12.0 and 90.0 m/sec. The inferior rectus neurons were predominantly located in the ventro-rostral part of the somatic oculomotor nucleus ipsilateral to the stimulated nerve. (2) The antidromic latency of 39 medial rectus units ranged from 0.5 to 2.1 msec, the conduction velocity along their axons was 14.5 and 64.0 m/sec. The medial rectus neurons were located in the dorsorostral part of the somatic nucleus ipsilateral to the stimulated nerve. (3) The antidromic latency of 17 superior rectus units was between 0.5 and 3.0 msec, and the mean conduction velocity was 27.2 m/sec. The superior rectus neurons were located in the most caudal part of the somatic nucleus contralateral to the stimulated nerve. (4) The antidromic latency of 34 inferior oblique neurons was between 0.4 and 6.6 msec, and the mean conduction velocity was 23.4 m/sec. The inferior oblique neurons were located in the dorsocaudal part of the somatic nucleus ipsilateral to the stimulated nerve.

The occurrence of catecholamine neurons in a parietal lobe ganglioglioma

A parietal lobe ganglioglioma in a 2‐year‐old girl was investigated ultrastructurally and immunohistochemically, using antiserum against tyrosine hydroxylase (TH), a rate‐limiting enzyme of the catecholamine (CA)‐synthesizing pathway. The tumor was composed essentially of neuronal and astrocytic cells. Ultrastructurally, numerous dense core vesicles measuring between 56 nm and 136 nm (mean, 90 nm) in diameter were observed in the neuronal cytoplasm and processes. The fact that the TH immunohistochemistry revealed many positive neuronal cells in the tumor tissue was of considerable interest. The implications and possible significance of the presence of CA neurons in this ganglioglioma are discussed.

Esthesioneuroepithelioma: a tumor of true olfactory epithelium origin

SummaryA case of esthesioneuroepithelioma was investigated ultrastructurally and immunohistochemically, using antibodies against neurofilament protein (NFP), glial fibrillary acidic protein (GFAP), keratin, neuron-specific enolase (NSE), S-100 protein (S-100), and tyrosine hydroxylase (TH). The tumor initially manifested as an epidural mass in the anterior cranial fossa in a 64-year-old man, and about 31/2 years later, autopsy further revealed extensive metastases to the lymph nodes of the neck and thoracic cavity. In the cranial and nasal cavities, the tumor was composed of fairly uniform, ill-defined cells arranged in nests which were surrounded by a fibrovascular stroma. These histological features were reproduced in the metastatic tumor nodules with frequent occurrence of tubular arrangements of the tumor cells. Ultrastructurally, two different cell types were well recognized by their characteristic morphological features, which were reminiscent of sensory neurons and sustentacular cells of the olfactory epithelium. No dense-cored secretory granules were observed in the tumor cells. Immunohistochemically, the tumor showed a variable number of cells positive for NFP, keratin, NSE and S-100. NFP was present in a relatively small number of cells, which were found diffusely in the nests. Keratin was observed in the cells mainly located at the periphery. NSE-positive cells tended to form irregular clusters in the center. A few S-100-positive cells were found, without any particular arrangement. These findings indicated that the present tumor, which actually arose in the superior nasal cavity, consisted of cells differentiating in at least two distinct directions, neuronal and epithelial, and strongly suggested that the tumor was of true olfactory epithelium origin, or more precisely, derived from the bipotential, undifferentiated basal cells of this epithelium.

Dural arteriovenous malformation with abnormal parenchymal vessels: an autopsy study

SummaryA 48-year-old man with dural arteriovenous malformation (AVM) is reported. Radiologically, the dural AVM was demonstrated mainly in the region of the left transverse sinus. Postmortem examination revealed dural AVM involving the bilateral transverse, superior sagittal and straight sinuses. In addition, numerous malformed venous vessels and extensive necrosis were observed mainly in the parenchyma of the brain stem and cerebellum. The present case suggests that dural AVMs may be associated with malformed venous vessels in the brain parenchyma.

Ultrastructural and biochemical studies on ouabain-induced oedematous brain.

SummaryOuabain, a specific inhibitor of active cation transport across cell membrane, was applied topically to brain surface of cats. The cerebral cortex to which 10−3 M ouabain was applied showed a spongy state, which was ultrastructurally revealed to be swelling of the neuronal cell processes, especially of dendrites. Astrocytes did not show swelling even in the most severely affected lesions. There was a marked increase in sodium with a slight increase of water in the most severely affected lesions. There was a marked increase in sodium with a slight increase of water in the cortex treated with 10−3 M ouabain. No evidence of increased vascular permeability was noted in the cortex, morphologically or biochemically. Electron microscopic cytochemistry to detect the sodium ion revealed that the increased sodium in the cortex accumulated in the swollen neuronal cell processes.It is speculated that neuronal rather than astrocytic elements might be highly dependent upon active cation transport, and that intracellular oedema in the brain tissue responsible for impairment of active cation transport might be related primarily to neuronal elements.

Esthesioneuroblastoma: a nasal catecholamine-producing tumor of neural crest origin

SummaryAn esthesioneuroblastoma in a 16-year-old male was studied ultrastructurally and immunohistochemically, using antiserum against tyrosine hydroxylase (TH), a rate-limiting enzyme in the catecholamine-synthesizing pathway. Tumor cells were fairly uniform in appearance, showing scantly cosinophilic cytoplasm and round to oval hyperchromatic nuclei, and were arranged in nests and cords of various sizes. Ultrastructurally, individual tumor cells had well-developed cell organelles including polyribosomes, microtubules, intermediate filaments, centrioles, Golgi apparatus and mitochondria. Secretory-like granules were occasionally found, predominantly in the cell processes. Immunohistochemically, many tumor cells were shown to be immunoreactive for TH. This finding strongly suggested that the present tumor was capable of producing catecholamines and that it might be derived from certain sympathetic neuronal cell nests in the superior nasal cavity.

An anaplastic cytokeratin‐immunopositive xanthomatous tumor involving the pharynx and clivus of a child: An ultrastructural and immunohistochemical study

An autopsy case of an anaplastic xanthomatous tumor involving the pharynx and clivus in a 2 year old girl was investigated ultrastructurally and immunohistochemi‐cally. The tumor was manifested as an epi‐ and subdural mass in the posterior cranial fossa involving the pharynx and clivus. The tumor showed an interlacing fascicular and pleomorphic pattern. The tumor cells contained numerous intermediate filaments, which were mainly tonofilaments, and lipid droplets, but did not have junctional complex. Immunohistochemically, most of the tumor cells were positive for cytokeratin, epithelial membrane antigen and vimentin, and some tumor cells were positive for myoglobin and a‐1 antichymotrypsin, but negative for S‐100, CD‐68 and glial fibrillary acidic protein. These findings suggest that this tumor was derived from epithelial cells, and showed xanthomatous appearance. A discussion of its differential diagnosis was conducted.

Regional Cerebral Blood Flow in Patients with Ischemic Cerebrovascular Disease

Regional cerebral blood flow (rCBF) was measured in 25 patients with transient ischemic attacks (TIA) and 34 patients with reversible ischemic neurological deficits (RIND) or ischemic strokes with full recovery. The rCBF measurements were performed by means of the 133Xe intracarotid injection method, using a scintillation camera and an on-line computer system. The rCBF data were analysed and compared with the computed tomography (CT) and angiographic findings on each patient. There was no significant difference in the average of the mean hemispheric values of rCBF (mean CBF) between TIA and RIND. The averages of mean CBF of TIA or RIND were significantly lower than those of the normal controls, and higher than those of the completed strokes. There was no correlation between the elapsed time from the last attack and the mean CBF in TIA. There was also no correlation between the elapsed time from the onset, or between the presence or absence of hemiparesis and the mean CBF in RIND. CT showed lacunae in 24% of TIA and 32% of RIND, whereas a cortical low density area was shown in only one case in each group. Angiographic abnormalities were found predominantly in the intracranial major arteries, rather than the extracranial carotid artery in both groups. Six patients of TIA (24%) and 6 of RIND (18%) had involvement of their extracranial internal carotid artery. There was no correlation between the mean CBF and angiographic findings. Although the mean CBF did not correlate to CT findings in TIA, it was significantly lower in RIND patients with lacunae on CT scans. Hemispheric pattern of flow distribution (HPFD) was disturbed in 88% of TIA and 74% of RIND. Focal ischemia was shown in only one case with RIND, whereas diffuse ischemia was shown in 2 cases with TIA and 5 cases with RIND. Loss of the hyperfrontal pattern which was thought to represent a mild diffuse cerebral dysfunction, was shown in 44% of TIA and 29% of RIND. Because diffuse involvement of HPFD was shown without reference for the elapsed time from the last attack of TIA or the onset of RIND, the authors support the ‘hemodynamic’ theory as opposed to ‘microembolic’ theory as the cause of TIA or RIND. It is concluded that TIA and RIND have the same causative factors, and the clinical difference of TIA and RIND is the only difference in recovery times between TIA and RIND.

FUSIFORM ANEURYSM OF BASILAR ARTERY ASSOCIATED WITH BILATERAL CHOROIDAL CYSTS

A case of large fusiform aneurysm of the basilar artery and bilateral choroidal cysts in the lateral ventricles is reported. The pathogenesis of the choroidal cysts is brieay discussed.