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Biomedical subjects

O Sato

Publications and source records attributed to O Sato.

At least 109 records · Page 6Linked to original sources
PubMed1994

The efficacy of shunting the hydrocephalic edema.

The efficacy of shunting the hydrocephalic edema was evaluated by means of transmission electromicroscopical observation (TEM) comparing ultrastructural alterations seen in either valid or invalid shunted feline hydrocephalus. Owning to shunt placement, deteriorated clinical symptoms recovered and one of the observed morphological alterations such as gliosis developed chronologically after the initiation of hydrocephalus. On the other hand, so called hydrocephalic edema observed in the region of periependymal tissue after shunt placement was improved not only in both valid and invalid shunted but also even in sham group however the extent of these alterations were different from each other. Among such observation, a distinct chronological linkage between the morphological alterations and clinical outcome was not noted. Our conclusions in present study were 1) shunt implantation results in the promotion of gliosis in the region of periventricular tissue in spite of the expected efficacy of shunt, 2) recovery of hydrocephalic edema was influenced not only by effective shunt implantation but also by the processes in chronological tissue reconstructions occurred in the natural course of hydrocephalus, and 3) early treatment of periventricular edema in hydrocephalus through shunting corrects the ill-fated neuro axis environments and reforming the intracranial conditions such as normalizing ICP and relieving hemodynamic distress seems to be more important than morphological recovery in treating hydrocephalus.

Animals↗
PubMed1994

Ultrastructural localization of P-glycoprotein on capillary endothelial cells in human gliomas.

The P-glycoprotein (P-Gp) encoded by the human multidrug-resistance gene MDR1 has been suggested to play certain roles in the blood-brain barrier (BBB). However, the detailed mechanism of the activity of P-Gp in multidrug-resistance (MDR) remains unclear in human glioma. We examined the localization of P-Gp in human glioma by immunohistochemical (IHC) and immunoelectron microscopic (IEM) methods with anti P-Gp monoclonal antibodies (C219, MRK16). We also examined MDR1 expression in primary glioma and xenografts by reverse transcription-polymerase chain reaction (RT-PCR) with human MDR1-specific primers. The IHC study showed no P-Gp expression on tumour cells but it was present on capillary endothelial cells and IEM analysis showed definitive localization on their luminal surface. MDR1 gene expression was detected in eight primary glioma and three normal brain specimens by RT-PCR, but not in glioma xenografts. The lack of MDR1 expression in these cells appears to be a consequence of the replacement of the original human stroma, including blood vessels, by murine stroma in glioma xenografts. The unique distribution of P-Gp on the capillary blood vessels was confirmed in human glioma by the results of immunohistochemical and molecular biological studies.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Hydrocephalus: is impaired cerebrospinal fluid circulation only one problem involved?

Hydrocephalus is a complex disease of the brain as a whole, and imbalance between cerebrospinal fluid (CSF) formation and absorption is not the sole mechanism involved in its pathophysiology. In the absence of a lymphatic system in the central nervous system, open communication between CSF and interstitial fluid (ISF) of the brain may contribute to maintaining homeostasis of the brain, keeping the microchemical environment in good balance. Membranes or cell layers separating CSF from ISF of the brain do not provide impermeability, so the CSF communicates with ISF across the ependymal layer and the pial surface of the brain. In contradiction of the classical theory, the CSF one may obtain at the cisterna magna, for instance, is different from the newly formed CSF out of the choroid plexus, because it has been modified by the free communication between CSF and ISF spaces as the CSF descends along the neural axis. Free flow of water and some smaller molecules provides a bidirectional movement of water and other materials, and this must play an important role in brain volume control. The significance of this role should not be overlooked in regard to the pathophysiology of hydrocephalus.

Animals↗
PubMed1994

Consensus: nosographic identification.

Since hydrocephalus cannot be regarded as a single entity but is a group of illnesses whose pathophysiology remains unexplained in many aspects, its classification is particularly important. Various types of hydrocephalus are discussed with special reference to their etiology. The need for more research work is stressed.

Brain↗
PubMed1994

Change in regional cerebral blood flow following glycerol administration predicts. Clinical result from shunting in normal pressure hydrocephalus.

Cerebral haemodynamics were measured in 22 adult patients with secondary normal pressure hydrocephalus (NPH) before and after glycerol administration to determine which patients might benefit from a shunt procedure. Of these 22 patients, 14 were found to be shunt-responsive (group 1) and 8 were shunt-unresponsive (group 2). Measurement of regional cerebral blood flow (rCBF) was performed by xenon-enhanced computerized tomography (XeCT). Clinical factors such as the Evans' index and the presence or absence of brain atrophy, periventricular lucency (PVL), ventricular reflux, stagnation of cerebrospinal fluid on cisternography, and increased intracranial pressure were not statistically significant predictors of shunt responsiveness. Preoperative rCBF values did not differ between groups 1 and 2. The rCBF value in every cerebral region of group 1 patients increased significantly after shunting except for the basal ganglia. On preoperative rCBF measurement, all rCBF values in group 1 significantly increased after glycerol administration except for the periventricular lucency (PVL). Patients in group 2, however, lacked such an increase in rCBF. We therefore propose that, in patients with secondary NPH, shunt surgery will be likely to be effective in those with a demonstrated rise in rCBF after glycerol administration.

Adult↗
PubMed1994

The use of a human dura mater allograft for the repair of a contaminated abdominal wall defect: report of a case.

A case report of an infected full-thickness abdominal wall defect treated successfully with a human dura mater allograft is presented. A review of the literature and a discussion of prosthetic abdominal wall repair is also included. A 46-year-old woman presented with multiple small bowel perforations and a large abdominal wall defect due to a motor vehicle collision. A gamma-irradiated human dura mater prosthesis was used to repair the large abdominal wall defect which had been infected by a jejunal fistula. After more than 4 years of follow-up, the patient is free of complications, including wound infection, herniation, and ileus. The human dura mater allograft is thus considered to be a useful prosthesis for repairing potentially infected wounds.

Abdominal Muscles↗
PubMed1994

Detection of norepinephrine distribution in rats with adrenal medulla autotransplants using 125I-meta-iodobenzyl guanidine.

The viability of autologous adrenal medullary transplants was evaluated using 125I-meta-iodobenzyl guanidine (MIBG), an adrenal medullary scanning agent. Bilateral cavities in the caudate nuclei were made stereotaxically in Wistar rats. One week later, the left adrenal medulla was resected by microsurgery, followed by reoperation of the cranium and implantation of a 0.5-1.0 mm diameter fragment of the adrenal medulla into the right caudate nucleus. Six weeks after the second operation, MIBG was administered intravenously. Specimens from both cerebral hemispheres, from the right adrenal medulla and blood were analysed by radioactivity counting. The radioactivity present in the blood of the transplanted group of 11.40 +/- 2.35 cpm mg-1 (mean +/- S.E.M.) was significantly higher than in the control group of 4.97 +/- 1.16 cpm mg-1 (P < 0.05). Radioactivity present in the right hemisphere of the transplanted group was 0.66 +/- 0.03 cpm mg-1, also significantly higher than in the control group which was 0.47 +/- 0.04 cpm mg-1 (P < 0.01). Autoradiography revealed increased radioactivity in the area of the transplants, which was also confirmed histologically.

3-Iodobenzylguanidine↗
PubMed1994

Perforin-secreting killer cell infiltration and expression of a 65-kD heat-shock protein in aortic tissue of patients with Takayasu's arteritis.

Cell-mediated autoimmunity has been strongly implicated in the pathogenesis of vascular cell injury in Takayasu's arteritis. To clarify the immunological mechanisms involved, we examined the expression of a cytolytic factor, perforin in infiltrating cells of aortic tissue samples from seven patients with Takayasu's arteritis. We also examined the expression of a 65-kD heat-shock protein (HSP-65), human leukocyte antigen classes I and II, and intercellular adhesion molecule-1 in the aortic tissue. Immunohistochemical studies showed that the infiltrating cells mainly consisted of gamma delta T lymphocytes, natural killer cells, macrophages, cytotoxic T lymphocytes and T helper cells, and that perforin was expressed in gamma delta T lymphocytes, natural killer cells, and cytotoxic T lymphocytes. In situ hybridization analysis also revealed expression of perforin mRNA in the infiltrating cells. Immunoelectron microscopic studies demonstrated that the infiltrating cells released massive amounts of perforin directly onto the surface of arterial vascular cells. We also found that expression of HSP-65, human leukocyte antigen classes I and II, and intercellular adhesion molecule-1 was strongly induced in the aortic tissue and might facilitate the recognition, adhesion and cytotoxicity of the infiltrating killer lymphocytes. These findings provide the first direct evidence that the infiltrating cells in the aortic tissue mainly consist of killer cells, and strongly suggest that these killer cells, especially gamma delta T lymphocytes, may recognize HSP-65 and play a critical role in the vascular cell injury of Takayasu's arteritis by releasing perforin.

Adult↗
PubMed1994

Microsurgical anatomy of the cavernous sinus.

The cavernous sinuses of 50 adult cadavers were examined to investigate the relationships of the blood vessels and cranial nerves, important structures during surgery in this sinus. The first and second divisions of the fifth cranial nerve were embedded in the deep dural layer of the cavernous sinus and were supplied by the two main branches of the intracavernous carotid artery. The meningohypophyseal artery supplied the sixth cranial nerve in Dorello's canal and the third and fourth cranial nerves where they entered the dura. The inferolateral trunk supplied the third, fourth, fifth, and sixth cranial nerves. The size of the meningohypophyseal artery was usually inversely proportional to the size of the inferolateral trunk. The capsular artery did not supply the cranial nerves. The cavernous sinus can be approached through various routes: a) superior, through the anteromedial or medial triangle; b) lateral, through the paramedial, Parkinson's, anterolateral, and lateral triangles; c) inferior, through the posterolateral and posteromedial triangles; and d) from the inferomedial walls. The choice of surgical approach depends mainly on the location of the lesion to be treated.

Carotid Arteries↗
PubMed1994

[A new classification for congenital hydrocephalus [perspective classification of congenital hydrocephalus (PCCH)] and postnatal prognosis (Part 3). Neuronal maturation process and prognosis in neonatal hydrocephalus].

Seventy cases of neonatal hydrocephalus were analyzed regarding the prognosis using the newly developed concept, namely "Perspective Classification of Congenital Hydrocephalus [PCCH]". The results revealed that the prognosis of premature-neonatal hydrocephalus is not necessarily poor even in the early periods of the neuronal maturation (PCCH Stage- II/III). It was suggested that the major underlying pathophysiological difference between the premature-neonatal and fetal hydrocephalus in the same stage of neuronal maturation is the intracranial pressure dynamics. It was concluded that the fetal hydrocephalus should be treated in the early period of neuronal maturation as the form of neonatal hydrocephalus to avoid the insult of such high intracranial pressure dynamics in utero.

Fetal Diseases↗
PubMed1993

[Usefulness of enhanced MR angiography by nitroglycerin].

We tried to use nitroglycerin to enhance MR angiography (MRA). Nitroglycerin has an effect to dilate vessels. We made a direct comparison between pre and post enhanced MRA (3 D-TOF technique). MRA after administration of nitroglycerin could depict more details of cortical branches without enhancement of background. So we recommend this method to be used in any examination of MR angiography.

Adult↗
PubMed1993

[Effect and complications of embolization therapy using absolute ethanol for renal arteriovenous malformation].

Transcatheter embolization therapy using absolute ethanol was accomplished in six patients with renal arteriovenous malformation. The effect of this therapy was considered to be good, because none of the patients has experienced recurrent hematuria. It is necessary to avoid the back flow of absolute ethanol. One patient had the particular complication of hydronephrosis caused by the incidental injection of absolute ethanol into the ureteral artery.

Adult↗
PubMed1993

Development of akinetic mutism and hyperphagia after left thalamic and right hypothalamic lesions.

A case of childhood post-traumatic akinetic mutism is presented. The patient showed a hyperphagic condition while recovering from akinetic mutism. He had lesions in the left interlaminal nucleus of the thalamus, right globus pallidus, and right dorsomedial nucleus of the hypothalamus. Laboratory data indicated slightly disturbed hypothalamic functions. In general, akinetic mutism can be seen with bilateral destructive lesions, while hyperphagia may occur after destruction of dorsomedial hypothalamic nucleus, but it is very rare. This is the first reported case of akinetic mutism caused by a unilateral lesion.

Akinetic Mutism↗
PubMed1993

A case of an aortocolic fistula occurring 27 years after aorto-femoral bypass surgery, treated successfully by surgical management.

The secondary aortoenteric fistula (AEF) is a rare but grave complication of aortic reconstructive surgery. We report herein a case of an aortocolic fistula which occurred 27 years after an aortofemoral bypass. A 69-year-old man was admitted to hospital following a sudden episode of melena. He had undergone aortofemoral bypass surgery with a prosthetic graft 27 years previously for occlusive disease of the right external iliac artery. Colonofiberscopy, CT scan, and angiography were performed, and an aortocolic fistula due to an aortic anastomotic pseudoaneurysm was diagnosed. The first-stage operation, being resection of the previously implanted graft, right hemicolectomy, and aortic stump closure were carried out with concomitant axillo-right femoral bypass. A femoro-femoral crossover bypass was performed in the second stage and the patients recovery followed uneventfully. This case constitutes the longest postoperative interval for an AEF recorded in the English literature.

Aged↗
PubMed1993

Cytochrome oxidase activity as a marker for periodontal sensory receptors in the rat.

Cytochrome oxidase activity was explored histochemically in axon terminals of periodontal Ruffini endings of rat upper incisors at both the light- and electron-microscopic levels. Staining clearly demonstrated ramified structures in the alveolar half of the periodontal ligament. These structures resembled the profiles of the axon terminals of the periodontal Ruffini ending previously demonstrated by an immunohistochemical method for neurofilament protein. Histochemically at the electron-microscopic level, the ramified structures were identified as true Ruffini endings in which each axon terminal was filled with reactive mitochondria. Two types of mitochondria were distinguished with respect to the localization pattern of reaction products; almost all mitochondria were positive for cytochrome oxidase activity, with only a few negative. As the enzyme activity did not decrease after demineralization, the findings suggest that cytochrome oxidase is a useful marker enzyme for demonstrating sensory receptors in the periodontal ligament. Histochemical methods for cytochrome oxidase may contribute to the light- and electron-microscopic morphological analysis of periodontal sensory receptors.

Animals↗
PubMed1993

Histochemical demonstration of acid phosphatase activity in terminal Schwann cells associated with Ruffini endings in the periodontal ligament of rat incisors.

Histochemical staining for acid phosphatase, a marker for lysosomal elements, distinguished rounded, intensely reactive cells from less reactive fibroblasts and osteoblasts in the lingual periodontal ligament. The highly reactive cells were located exclusively in the alveolar half of the ligament. Double staining for acid phosphatase and S-100 protein confirmed that these reactive cells were identical with the terminal Schwann cells associated with periodontal Ruffini endings. Electron microscopically, reaction products for acid phosphatase were observed in the lysosomes and Golgi apparatus in the paranuclear cytoplasm of the terminal Schwann cells. As the terminal Schwann cells associated with the Ruffini endings are assumed to be capable of synthesizing exportable proteins, acid phosphatase in this type of cell may be involved in the processing of macromolecules in synthetic and/or secretory pathways.

Acid Phosphatase↗