Biomedical subjects
Publications and source records attributed to O Sato.
A 53-year-old male presented with a dissecting aneurysm of the extracranial distal internal carotid artery (ICA) treated by aneurysm removal with interposition of a saphenous vein graft. The surgical approach involved sectioning of Riolan's nosegay.
In two cases of entrapment of the temporal horn, computed tomography demonstrated the typical appearance of a comma-shaped homogeneous area isodense with water surrounded by a periventricular low-density area. The cause was probably choroid plexitis resulting in obstruction of the cerebrospinal fluid pathway at the atrium. External drainage followed by shunt emplacement is indicated.
The distribution and subcellular localization of nerve growth factor receptor (NGFR) in human teeth has been investigated by immunohistochemistry at the light and electron microscopic levels. Many nerves in the dental pulp were intensely immunoreactive for NGFR. The pattern of distribution was largely similar to that of nerve fibers demonstrated by immunostaining for neurofilament protein (NFP), the most universal marker protein for pulpal nerves. In the predentin and dentin, more nerve fibers were intensely immunoreactive for NGFR than were demonstrable with NFP-antibodies. Immunoelectron microscopy showed that the NGFR-immunoreactivity was localized on the axoplasmic membrane in unmyelinated axons and on the outside of accompanying Schwann cells. No NGFR-immunoreactivity was found on the axons of myelinated nerves nor their supporting cells.
A thoracoabdominal aortic aneurysm (TAAA) involving major abdominal branches remains still difficult to be managed. From 1983 to 1990, we successfully operated five such cases. Our operative strategy for TAAA which necessitates concomitant reconstruction of four major abdominal branches is i) to utilize temporary bypass to maintain distal perfusion during aortic cross-clamping, ii) to reconstruct bilateral renal arteries prior to aortic clamping in order to shorten renal ischemic time as much as possible, iii) to reconstruct celiac and superior mesenteric arteries by Crawford's method, iv) to reconstruct two pairs of intercostal arteries by using diagonal anastomosis in the proximal site, and v) to divide the left renal vein temporarily for easy manipulation of renal arteries. All five cases were recovered uneventfully. This procedure, in which the renal ischemic time is saved as short as possible, is considered a safe and reasonable one for thoracoabdominal aortic aneurysms.
Sixty-three patients (aged from 4 to 75 years) who had suffered severe head injury or cerebrovascular disease were placed on barbiturate regimens in which intravenous administration was given in amounts of 1-4 mg/kg/hr. Dobutamine and dopamine were also administered to prevent cardiac failure and renal failure. Immediate and delayed complications caused by barbiturate therapy were investigated and analyzed. Immediate complications included tachycardia which was seen in 16 cases (25%), and hypotension in 14 cases (22%), respectively. Higher incidence of those complications was noted among the patients who underwent surgery. Delayed complications included hypokalemia (41 cases, 65%), liver dysfunction hypernatremia (24 cases, 38%), infection (21 cases, 33%), cardiac failure (8 cases, 13%) and renal failure (1 case, 2%), respectively. Therefore, in patients treated under barbiturate regimens great care should be taken in order to avoid above mentioned complications.
A simple direct precise localization with a CT scan for convexity lesions is presented. The shape of the normal calvarium was analyzed and a characteristic pattern was obtained, that is, one spherical surface in the frontal area and 6 flat planes in the temporal, parietal and occipital areas. The temporal plane is perpendicular to the orbito-meatal line (OML), while the parietal plane declined 29 degrees in the A-P view, and the occipital plane declined 60 degrees in the lateral view. A summit of these three planes forming the parietal tubercle, and the crest following the tubercle between the parietal and occipital planes were detected either by CT scan, or by palpating the skull. Conventional methods of preoperative localization include measurement and calculation from the base line such as OML, or obtaining a CT scan with a marker on the scalp. The former might have an error that will be amplified in the parietal region that would not be negligible. The latter is a rather troublesome method demanding that the CT scan be taken after shaving the hair. Landmarks utilized for the localization should be identified both on the CT scan and on the scalp or skull. These involved OML, coronal suture, parietal tubercle, inion, pineal body, midline and so on. Of these, the coronal suture runs almost perpendicular to the OML and would be the best landmark for the localization in the parietal area.(ABSTRACT TRUNCATED AT 250 WORDS)
Intracranial arterial reconstructive techniques were used in three patients for whom conventional neck clipping was not feasible due to the size, location or symptoms of their aneurysms. In the first case, complicated by subarachnoid hemorrhage, a giant aneurysm in the right middle cerebral artery was excised and the stump of the parent arteries was reconstructed in end-to-end and end-to-side fashion. The second case had a large thrombosed aneurysm in the left vertebral artery compressing the medulla oblongata, with small perforators originating from the proximal posterior inferior cerebellar artery (PICA) feeding the brainstem. The PICA was transposed to cerebellar cortical artery and the aneurysm excised. The third case presented with TIA and small infarctions were observed in the left thalamus. A giant, partially thrombosed, aneurysm in the left posterior cerebral artery (PCA) was trapped with a revascularization of the distal PCA from the superior cerebellar artery in side-to-side fashion. Indications for these intracranial arterial reconstructions in aneurysmal surgery were discussed and pertinent literature was reviewed.
A case of bilateral panophthalmoplegia developed after paranasal malignant lymphoma is described, and previously reported cases are reviewed. A 74-year-old female was hospitalized with the chief complaints of bilateral ptosis and bilateral deep orbital pain that had developed over a 10-day period. Neurological examination revealed bilateral dilated pupils, panophthalmoplegia, and hypalgesia in the area of the ophthalmic nerve on both sides. Laboratory studies and endocrinological examination were free from abnormal findings. Skull X-ray films showed a soft tissue lesion in the sphenoidal and ethmoidal sinus and this was associated with bony structure destruction in the surrounding area. Computed tomography demonstrated a heterogeneously enhanced mass lesion in the paranasal sinus extending into the intrasellar region and bilateral cavernous sinus. Meticulous investigation has so far revealed no distant lesions either in the thoracic or abdominal lesions. Subtotal tumor resection was undergone via the transsphenoidal route at which time tumor extension into the nasal cavity and sellar floor destruction were confirmed. Diffuse and mixed B-cell type malignant lymphoma was the pathological diagnosis. Postoperatively, improvement of abnormalities of pupils, panophthalmoplegia, and ptosis was achieved but this was only transient. Despite focal radiation therapy and repeated chemotherapy, the patient died 14-months after the diagnosis was made. On reviewing the literature, it is shown that the incidence of bilateral panophthalmoplegia among patients who develop disturbance of ocular movement is extremely low (0.4%).(ABSTRACT TRUNCATED AT 250 WORDS)
The topographical relationship between Ruffini endings and the surrounding collagen fibers in the periodontal ligament of hamster incisors was investigated by means of both immunohistochemistry for neurofilament protein (NFP) and electron microscopy. Periodontal Ruffini endings, a type of stretch receptor, were present exclusively in the alveolar half of the periodontal ligament. Their axon terminals were densely and regularly associated with transverse collagen fibers, possibly forming a mechanoreceptive complex. Since blood sinuses with frequent anastomoses extended throughout the alveolus-related part, the densely innervated collagen bundles were separated from each other by the vascular spaces. Electron microscopic observation of specimens stained with tannic acid revealed a linkage between the axon terminals of the Ruffini endings and the surrounding collagen filaments. The axon terminals were enveloped by multiple layers of the basal lamina, which were penetrated by collagen filaments. The irregularly arranged collagen filaments were sandwiched between electron-dense laminae of the multilayered basal lamina. The possible mechanism of mechanoreception by the periodontal Ruffini endings is discussed on the basis of the immunohistochemical and ultrastructural findings.
Magnetic Resonance Angiography using a time-of-flight method was performed on two cases with arterial-portal shunting (A-P shunt). Each case was examined both with and without presaturation applied above the diaphragms. Signal intensity in the portal vein on these cases decreased with presaturation. This presaturation normally eliminates signal from inflowing spins in the artery but never effect on that in portal vein. Therefore the decrease of signal intensity in the portal vein with presaturation indicates the arterial inflow to the portal vein.
Nerve fibres showing CGRP-immunoreactivity were exclusively distributed around blood vessels in the periodontal ligament of normal teeth. The CGRP-positive nerves as well as the vessels were more dense during tooth movement and reached a maximum density and intensity of immunoreaction after 3 days. After that, the immunoreactive nerves gradually disappeared, and returned to the control level by the 7th day. Some of the CGRP-nerves were adjacent to bone resorptive lacunae at 3 days when active remodelling of alveolar bone was taking place. These findings suggest that the distribution of CGRP-positive nerves is dynamically changed around the blood vessels in the periodontal ligament during tooth movement, and that CGRP might affect the regulation of blood flow in the ligament. CGRP is possibly involved in the tissue remodelling, directly or indirectly, in addition to its function as a neurotransmitter.
There were 55 patients (soft disc, 21 and spondylosis, 34) who underwent anterior cervical discectomy without fusion (ACD) using an operating microscope. Discectomy of a single level was performed on 48 cases and two levels on 7. There were 37 patients with radiculopathy, and 18 patients with myelopathy or myeloradiculopathy who were followed clinically for 2-13 years postoperatively. Overall 81% of patients were improved in soft disc herniation, and no significant differences were noted between the group of radiculopathy and myelopathy. In spondylosis all but one patient reported initial relief of their preoperative symptoms; however, overall improvement was noted in only 16 patients (47%). The causes of symptomatic deterioration after ACD for spondylosis were later symptomatic recurrence in 5 patients, severe neck pain in 4, and development of new symptoms due to adjacent spur formation in 2. The authors eventually added interbody fusion in 4 cases. Cervical spine roentgenograms almost always showed a loss of height of the interspace and an anterior angulation immediately after ACD, but the alignment of the spine tended to improve with time, so that, at last follow-up, 82% had a good alignment. A spontaneous osseous fusion occurred in 74% of cases. An adjacent spur formation was observed in 3 patients with spondylosis. The most troublesome complication was neck and/or scapular pain. This pain usually subsided spontaneously, but this continued for more than 4 years postoperatively in 4 patients with spondylosis. Using an operating microscope ACD is a safe and effective procedure for patients with soft disc herniation, but the authors still prefer anterior cervical discectomy with interbody fusion for the patients with advanced spondylosis.
Ruffini endings in the periodontal ligament of rodents are ensheathed by a special type of terminal Schwann cell with a particularly developed rough endoplasmic reticulum and Golgi apparatus, and further enveloped by a characteristic multi-layered structure. In order to reveal the functional significance of the structures, localization of a laminin molecule in the periodontal Ruffini endings of rats was immunohistochemically investigated at the levels of light and electron microscopy. Immunostaining using an anti-laminin serum clearly demonstrated the profiles of the Ruffini endings as well as those of the blood vessels. Ultrastructurally, reaction products for laminin were deposited in the entire thickness of the multi-layered structure, supporting the idea that this structure is derived from the basal lamina. The basal lamina, immunoreacting with laminin antiserum, was penetrated by periodontal collagen fibers, possibly serving as an adhesive device between the Ruffini endings and surrounding collagen fibers. The laminin immunoreactive materials were also recognized in the vesicles and caveolae of the terminal Schwann cells which tended to gather at the interstitial surface of the cells. The terminal Schwann cells are therefore believed to be directly involved in the formation of the multilayered basal lamina through the active production of its materials.
Balloon compression of the left IXth and Xth cranial nerves and ventrolateral medulla oblongata in dogs resulted in statistically significant increases in blood pressure without obvious changes in cardiac output. Five of 21 hypertensive patients with trigeminal neuralgia or hemifacial spasm demonstrated normalized blood pressure following microvascular decompression for arterial compression of the brainstem in the area of the IXth and Xth cranial nerves on the left. Our experimental and clinical results suggest that neurogenic hypertension caused by the vascular compression of the medulla oblongata can be relieved by microvascular decompression.
A 35-year-old male with a sudden onset of severe vertigo and vomiting had a fusiform aneurysm of the distal portion of the left posterior inferior cerebellar artery. The symptoms were caused by cerebellar infarction probably due to an embolism from the aneurysm. The aneurysm was excised and the artery reconstructed by end-to-end anastomosis with an excellent outcome. Histological examinations showed mural thrombus but no wall dissection.
A 38-year-old male presented with moyamoya disease. Occlusion of the bilateral proximal posterior cerebral arteries (PCAs) resulted in homonymous 3/4 (right half and left lower quadrant) anopsia and various mental symptoms. To prevent impending cortical blindness, revascularization to the right PCA was performed by occipital artery (OA) to calcarine artery anastomosis. His neurological state was stabilized. OA-cortical PCA (calcarine artery) anastomosis is an alternative to omentum transplantation or occipital burr hole procedures for impending cortical blindness.
This report describes a method for measuring regional cerebral blood volume (r-CBV), by simultaneously using dynamic computerized tomography (DCT) and stable Xenon-enhanced CT (Xe CT). Local cerebral blood flow (CBF) was measured using a Xe CT blood sampling method, and mean transit time (MTT) was calculated using DCT after a rapid injection of iodinated contrast material. A functional image of r-CBV was obtained from multiplication of CBF and MTT on each pixel using the formula: CBF x MTT = CBV. This calculated value is not suitable to indicate a r-CBV which directly reflects cerebral microcirculation. Accordingly, only a comparative estimation of relative r-CBV images is applicable. However, laterality of image and comparison of serial studies are useful in hemodynamic evaluations, especially in ischemic cerebrovascular diseases, because they indicate hemodynamic reserve within the hypoperfused region.