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Biomedical subjects

O Sato

Publications and source records attributed to O Sato.

At least 19 recordsLinked to original sources
PubMed1992

[A clinical trial of whole liver simultaneous dynamic MR imaging and its usefulness].

A clinical trial of whole liver simultaneous dynamic MRI was done. In 23 second whole liver was able to be scanned using parameters of filed echo method as follows: TR = 315 msec, TE = 7 msec, Flip angle = 70 degrees or 90 degrees, MAT = 50%, ECD = 60%, FOV 40 cm and no presaturation. Even 2-3 mm nodules of metastatic tumors and small daughter nodules of hepatocellular carcinoma such as 5 mm were demonstrated in the arterial phase clearly.

Adult↗
PubMed1992

[Multi-directional stereo viewing of MR angiography].

A new method was developed to display MR angiographic images. Nine MR angiographic images rotated along the cranio-caudal axis with ten incremental degree were constructed. These images were printed from left-anterior-oblique view to give a stereoscopic effect. With the stereoscopic viewing of these images, multiple stereoscopic images with different viewing directions were observed at once. Anatomical relationships of the vessels were more clearly understood than usual stereoscopic viewing. This multi-directional stereo viewing method is useful to display not only the MR angiographic images but also other multi-viewing techniques.

Blood Vessels↗
PubMed1992

Single photon emission computerized tomography in childhood hydrocephalus.

Single photon emission computerized tomography (SPECT) is now widely used as one of the tools in evaluating cerebral blood flow (CBF). The authors report the CBF changes in childhood hydrocephalus. Five pediatric cases studied by 123I-IM SPECT in children are presented. The authors counted radioactivities both in early and delayed images in each patient, and calculated the reabsorption ratio (RR). Two negative-RR cases and three positive-RR cases were found. All of the negative-RR patients had a poor prognosis, while all of the positive-RR patients had a favorable outcome.

Cerebrovascular Circulation↗
PubMed1992

Discrepancy of xenon concentrations between end-tidal and blood collection methods in xenon-enhanced computed tomographic measurements of cerebral blood flow.

Using xenon-enhanced computed tomography for the study of cerebral blood flow, simultaneous measurements of end-tidal and arterial blood xenon concentrations using the blood collection method were performed to investigate the validity of substituting the end-tidal for the arterial blood xenon concentration. Simultaneous measurement by both methods was performed 68 times in 27 patients. There was no statistical correlation between the arterial blood accumulation rate constant obtained by arterial blood and end-tidal samples, nor between the arterial blood saturation value obtained by the two methods, even when correction was made for age. In brain tissue, all parameters calculated using the end-tidal concentration were lower than those using arterial blood. We therefore suggest that cerebral blood flow values calculated using end-tidal xenon concentration are useful only for qualitative cerebral blood flow mapping, and not applicable to absolute values of cerebral blood flow.

Adolescent↗
PubMed1992

Surgical treatment of Takayasu arteritis.

From 1959 to 1991, 93 patients underwent vascular reconstruction for Takayasu arteritis at our institution. The details of the cases were as follows: 16 were of type I (brachiocephalic ischemia), 48 type II (hypertension), 13 type III (extensive lesions with cerebral ischemia and hypertension), and 16 type IV (aneurysms). Carotid reconstruction, repair of atypical aortic coarctation, renovascular reconstruction, and aneurysm repair were performed independently or in combination. Nine operative deaths occurred, 8 cases of which were operated before 1970. The most serious of the delayed complications was suture line aneurysm formation, which was encountered in ten cases. The aneurysms were often found long after the operation, some of them developing even after more than 20 years. Takayasu arteritis is characterized by extensive inflammation and destruction of the medial elastic fibers and long term postoperative observation is mandatory to improve the late survival rate.

Aortic Aneurysm↗
PubMed1992

False aneurysm as a late complication of division of a patent ductus arteriosus.

A 58-year-old male patient who had a huge false aneurysm as a late sequela of division of patent ductus arteriosus was surgically managed with success. It is noteworthy that 24 years had elapsed from the initial operation until recognition of the aneurysm. The pathogenesis and method of the surgical treatment are discussed.

Aortic Aneurysm↗
PubMed1992

Molecular shape of dystrophin.

The molecular shape of dystrophin has been reported to be a 175 nm flexible rod [Pons, F. et al. (1990) Proc. Natl. Acad. Sci. USA 87, 7851-7855] or a 120 nm dumbbell [Murayama, T. et al. (1990) Proc. Jpn. Acad. 66B, 96-99]. The present work revealed that 100 nm flexible rods with or without spheres were predominant in highly purified dystrophin preparations. When the sample was subjected to gel filtration, dystrophin oligomers were isolated just after the void volume and the fraction largely consisted of dumbbell-shaped molecules. From various rotary-shadowed images, it was suggested that dystrophin is a rod with spheres at both ends, approximately 110 nm long and 2 nm wide. It appeared that this monomer binds to another monomer in a staggered way, forming a dimer, and the dimers associate with each other side-by-side, forming a dumbbell-shaped tetramer, 130 nm long and 5 nm wide. The tetramers form an end-to-end aggregate. It seemed that the dumbbell structure was not affected by alkaline (pH 11) treatment to dissociate dystrophin associated glycoproteins, but was deteriorated by detergent, NP-40, Triton X-100, or CHAPS, used for solubilization of membrane-bound dystrophin.

Alkalies↗
PubMed1992

Intracranial paramedian hourglass-shaped dermoid associated with hereditary steatocystoma multiplex.

This is the first report to describe the coexistence of two rare diseases, intracranial paramedian hourglass-shaped dermoid and steatocystoma multiplex. A 46-year-old female with a history of steatocystoma multiplex, bradydactylies and kyphosis showed oscillopsia, ataxia and hemifacial spasm. MRI findings suggested a giant dermoid cyst extending from the left middle temporal fossa to the cerebellopontine angle, and this was confirmed surgically. We propose the involvement of some genetic factor or pathological process common to both disorders, steatocystoma multiplex and dermoid. From the clinical point of view, patients with cystic skin lesion should also be checked for intracranial lesion.

Brain Neoplasms↗
PubMed1992

Three types of membranous ATPase on rat liver lysosomes.

At least three types of vanadate-insensitive membranous ATPase were identified on rat liver lysosomes: bafilomycin A1-sensitive Mg(2+)-ATPase (H(+)-ATPase), N-ethylmaleimide (NEM)-sensitive but bafilomycin A1-insensitive Mg(2+)-ATPase (ATPase I), and NEM-insensitive Ca2+/Mg(2+)-ATPase (ATPase II). They showed different sensitivity to chemicals and ions with apparent molecular masses of 700-800, 500-650, and 360 kDa, respectively. Of these membranous ATPases, H(+)-ATPase seemed to constitute only one tenth of the ATPase activity on rat liver lysosomes and to be the only ATPase that exposed its active site to the cytoplasmic side of the lysosomal membranes.

Adenosine Triphosphatases↗
PubMed1992

Innervation of the periodontal ligament in the dog with special reference to the morphology of Ruffini endings.

The distribution and terminal formation of nerves in the periodontal ligament of dog incisors and canines were investigated by immunohistochemistry for neurofilament protein (NFP) and by electron microscopy. The NFP-immunoreactive nerve fibers were found to be densely distributed in the apical third of the periodontal ligament, while they were sparse in the coronal two thirds. Most of the nerve endings in the periodontal ligament showed a tree-like appearance and resembled those nerve endings demonstrated in the periodontal ligament of human and monkey under the category of free nerve endings. Presumable axon terminals of these were slightly thicker than preterminal portions, running along periodontal collagen fibers and tapering within them. In light microscopic images, at least, they differed from the Ruffini endings which are commonly seen in rodents, displaying a glove-like configuration with extremely expanded tips. Under the electron microscope, however, the tree-like endings of the dog appeared similar to the Ruffini endings of rodents: their terminals were filled with mitochondria, covered with a cytoplasmic process of a Schwann cell, and surrounded by collagen fibers. These ultrastructural findings, combined with the results of previous physiological studies suggest that the nerve endings demonstrated in the present study can be identified as Ruffini endings. It is even stressed that the dog-type of Ruffini ending can be regarded as a representative of the sensory receptors in the mammalian periodontal ligament. In addition to these endings, knobbed endings, corpuscular (lamellated and glomerular) endings, and free nerve endings were rarely encountered in the periodontal ligament of incisors and canines of the dog.

Animals↗
PubMed1992

Histochemical and immunohistochemical demonstration of macrophages and dendritic cells in the lingual periodontal ligament of rat incisors.

The distribution of macrophages in the lingual periodontal ligament of rat incisors was surveyed by histochemical and immunohistochemical methods. Numerous macrophages showing intense ACPase reactions were located primarily in the shear zone of the periodontal ligament. Immunostaining with an ED1-monoclonal antibody that recognizes various subpopulations of macrophages revealed plentiful positive cells showing flamelike profiles throughout the periodontal ligament, in addition to regular macrophages associated with sinusoidal blood vessels. A similar distribution of flamelike cells expressing Ia antigens was demonstrable with immunostaining using an OX6-monoclonal antibody. A consecutive staining of sections for ACPase histochemistry followed by immunoreactions for Ia antigens revealed the presence of two types of the flamelike cells in the periodontal ligament: one with and the other without distinct ACPase activity, corresponding to the macrophage and the dendritic cell, respectively. Either type of flamelike cells was located in the bone-related and shear zones, whereas only dendritic cells without ACPase activity were restricted to the tooth-related zone. OX6-immunonegative cells showing ACPase reactions were also found in the periphery of the sinusoidal blood vessels. Our data are the first to demonstrate the abundance of macrophages and dendritic cells expressing Ia antigens throughout the lingual periodontal ligament of rat incisors. In addition to regular macrophages, an exclusive localization of macrophages with flamelike extensions has been demonstrated in the bone-related and shear zones of the ligament. The region-specific arrangement of macrophages and dendritic cells with various histochemical and immunological features suggests that the periodontal ligament of rat incisor is a useful model for analyzing the process of differentiation of antigen-presenting cells.

Acid Phosphatase↗
PubMed1992

Immunoelectron microscopic observation of calcitonin gene-related peptide (CGRP)-positive nerves in the dental pulp of rat molars.

The ultrastructure of nerves containing immunoreactivity for calcitonin gene-related peptide (CGRP) was investigated in the dental pulp of rat molars. The immunoreactivity was recognized predominantly in unmyelinated nerve fibers, and sparsely in a few myelinated fibers. It was localized throughout the axoplasm, as well as in the large cored vesicles. Small clear vesicles and mitochondria were free of the immunoreaction. The CGRP-immunoreactive nerves were frequently observed to terminate, being devoid of Schwann cell investment, in the vicinity of blood vessels in the coronal pulp, suggesting that CGRP may be involved in the regulation of pulpal blood flow. Moreover, CGRP-immunoreactive axon terminals containing numerous small clear vesicles, a few large cored vesicles and mitochondria were recognized in contact with the cell bodies of odontoblasts and their processes in the dentinal tubules. Although specialized synaptic ultrastructures were not recognizable, a functional association of CGRP nerves and odontoblasts was suggested. Thus, CGRP in the dental pulp appears to have multiple functions, including vascular regulation and sensory transduction.

Animals↗
PubMed1992

Entrapment of the temporal horn: a form of focal non-communicating hydrocephalus caused by intraventricular block of cerebrospinal fluid flow--report of two cases.

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.

Adult↗
PubMed1992

Immunocytochemical localization of nerve growth factor receptor (NGFR) in human teeth.

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.

Axons↗
PubMed1992

[Operative strategy for thoracoabdominal aortic aneurysm with concomitant reconstruction of four main abdominal branches].

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.

Adult↗
PubMed1992

[Problems in general management during barbiturate therapy].

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.

Adolescent↗