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Biomedical subjects

O Sato

Publications and source records attributed to O Sato.

At least 163 records · Page 9Linked to original sources
PubMed1991

[Optimal hypervolemic therapy for symptomatic vasospasm].

Thirty-five patients with symptomatic vasospasm (SV) following aneurysmal subarachnoid hemorrhage (SAH) were managed according to a method based on hemodynamic manipulation, monitored by Swan-Ganz catheter. Nine out of these had delayed surgery. For those who developed SV, the pulmonary wedge pressure (Pcwp) and/or central venous pressure (CVP) were immediately increased up to the point at which neurological deficit was reversed by rapid injection of fresh frozen plasma, albuminates, low molecular dextrose, and glycerol. On this regimen, patients were closely observed for any neurological change. Then the hemodynamic parameters were maintained as optimal values until they could be reduced below optimal values without reappearance of neurological deficit. In inoperable patients, special attention was given in making a decision about discontinuing the regimen. The results were compared with thirty-seven patients with SV who were treated with conventional hypervolemic therapy (CHT) by continuous administration of albuminates. In the treatment of CHT, optimal values could hardly be established, so the same hemodynamic parameters were applied in all the cases. From this study, in the majority of the cases optimal values were found as follows: Pcwp up to 10-15 mmHg, and CVP below 11 cmH2O. On the contrary, in 20% of patients, neurological deficit was reversed by increasing CVP to a point not above 7 cmH2O. Correlation between neurological reversal and systemic blood pressure was not statistically significant. After this regimen (OHT), 74% of patients showed immediate improvement after volume expansion, and, in 80%, outcome was good, while 20% died. The motor function at the time of discharge was more than 3 on the manual test in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Central Venous Pressure↗
PubMed1991

[A case report: abscess of the cavum septi pellucidi].

A rare case of an abscess in the cavum septi pellucidi (CSP) is described and previously reported cases are reviewed. A 60-year-old male was admitted to the hospital because a diagnosis of cerebellar hemisphere infarction was made on CT scan. Seven years earlier, the patient had undergone a craniotomy for aneurysm clipping, and a ventriculo-peritoneal shunt was installed for normal pressure hydrocephalus 14 days after the aneurysmal rupture. On his second hospitalization CT scan also demonstrated CSP but this was not associated with ventriculomegaly. He was placed on a rehabilitation regimen and his hospital course was uneventful. Two months later, however, he developed hyponatremia due to the syndrome of inappropriate secretion of antidiuretic hormone. After analysis of CSF obtained from the shunting device, a diagnosis of meningitis was made and CSF culture revealed E. coli infection. A part of the peritoneal tubing was torn and missing when the tube was removed from the peritoneal cavity and converted to outer drainage. Being treated with intrathecal and intravenous antibiotics administration, the meningitis subsided. However, CT scan taken twelve days after the onset of the infection showed an abscess in CSP which showed ring enhancement after contrast media. Therefore, the patient continued to receive intravenous antibiotics to counter the mass effect due to the abscess. The abscess had disappeared on follow-up CT scan obtained ten days later. The patient, however, eventually expired after iatrogenic hypernatremia associated with acute renal failure. The patient was submitted to an autopsy. The authors speculate that the abscess developed through a retrograde cisternal route after infection which had originated from bowel perforation by the peritoneal shunt tube.

Brain Abscess↗
PubMed1990

Cholinesterase activity in terminal Schwann cells associated with Ruffini endings in the periodontal ligament of rat incisors.

A nonspecific cholinesterase activity was demonstrated in terminal Schwann cells associated with Ruffini endings in the periodontal ligament of rat incisors at the light and electron microscopic levels. The terminal Schwann cells are ultrastructurally characterized by a well-developed Golgi apparatus and rough endoplasmic reticulum. The cells in this study were positive for nonspecific cholinesterase, whereas ordinary Schwann cells associated with more proximal nerve fibers reacted negatively. The reaction products were densely deposited in the cisternae of the rough endoplasmic reticulum and along the nuclear envelop. A moderately intense labeling was found in the cytoplasmic extensions, in which the reaction products gathered in caveolae and vesicles. These findings indicate that nonspecific cholinesterase is a useful marker to distinguish terminal Schwann cells from ordinary Schwann cells and that the enzyme may be synthesized in the rough endoplasmic reticulum and conveyed toward the axon terminals. Since this enzyme has been known to be shared by the inner bulb of Pacinian corpuscles and the lamellar cells of Meissner's corpuscles, its possible involvement in mechanoreceptive functions in these specialized Schwann cells deserves further investigation.

Animals↗
PubMed1990

Energy metabolism in kaolin-induced hydrocephalic rat brain. Assessed by phosphorus (31P) magnetic resonance spectroscopy and the diversity of lactate-dehydrogenase and its isoenzyme patterns.

Energy metabolism in kaolin-induced hydrocephalic rat brain was assessed by means of 31-phosphorus magnetic resonance spectroscopy and measurement of the activity of lactate dehydrogenase (LDH) as well as its isoenzyme patterns. Decreases in beta-adenosine triphosphate and phosphocreatine were observed in hydrocephalic rat brains. While the intracellular pH was decreased at 2 to 4 weeks, it showed some recovery 6 weeks after injection of kaolin. The activity of LDH increased in the hydrocephalic state, and its isoenzyme-pattern changes were as follows: the LDH5 fraction was predominant in 1-week to 4-week rats while the LDH4 fraction was predominant in 4-week rat brains, and at 6-weeks, the LDH4 and LDH5 fractions were decreased. These data from rat brains with kaolin-induced hydrocephalus indicate that anaerobic glycolysis is the primary pathway of energy metabolism in the acute hydrocephalic state, while in the chronic state the emphasis shifts to aerobic glycolysis.

Animals↗
PubMed1990

Effect of direct-current stimulation on the growth plate. In vivo study with rabbits.

Electrical stimulation of 8 microA direct current was applied to the femoral distal growth plate of young rabbits for periods of 1, 2, and 3 weeks to examine the effect on bone growth. The results were analyzed using X-ray measurement, histological observation including tetracycline labeling, and glycosaminoglycans analysis. No obvious differences between the stimulated side and the control side were observed in the morphological and biochemical studies, but characteristic thickening of the growth plate caused by the accumulation of hypertrophic cells was found in the group stimulated for 2 weeks. Electricity affects the cell behavior of the growth plate, but it is necessary to find more appropriate conditions to stimulate obvious bone growth.

Animals↗
PubMed1990

Congenital arteriovenous fistula in the gluteal region--a report of five cases.

Five cases of congenital arteriovenous fistula in the gluteal region have been encountered in our department in the past 20 years. In all cases, the fistulous masses were in the connective tissue between the gluteal muscles and well-localized. Preoperative angiography showed the feeding arteries to be the superior gluteal, the inferior gluteal, and/or the lateral femoral circumflex arteries, and all the arteriovenous fistulae were excised almost completely with success. In this report, we emphasize the importance of precise estimation of the feeding arteries on preoperative angiography and ligating them before excising the fistulous masses, to ensure safe surgical treatment.

Adolescent↗
PubMed1990

Aortobronchial fistula after an aortic operation.

A 71-year-old man with a postoperative aortobronchial fistula was successfully treated. The fistula occurred between the left lower lobe and the descending thoracic aorta, to which a distal anastomosis of a temporary bypass graft had been placed during thoracic aortic aneurysmectomy 3 years before. For saving patients with this complication, early surgical treatment during episodes of intermittent hemoptysis is important. The use of an omentum pedicle flap for the isolation of the suture line is a important adjunct.

Aged↗
PubMed1990

Nerve terminals in human periodontal ligament as demonstrated by immunohistochemistry for neurofilament protein (NFP) and S-100 protein.

Nerve terminals in the human periodontal ligament were investigated by immunohistochemistry for neurofilament protein (NFP) and glia-specific S-100 protein. The human periodontal ligament was found to be innervated by NFP-immunoreactive nerve fibers, and contained free and specialized nerve endings; essentially all these nerve fibers were associated with S-100 protein-immunoreactive elements. Free nerve endings showing tree-like ramifications were frequently observed along the whole length of the tooth. The specialized nerve endings consisting of thick nervous elements were classified into four types as follows: Ruffini-like endings which were composed of expanded nerve terminals arranged in a dendritic fashion were found mainly around the root apex; coiled nerve endings were located in the mid-region of the periodontal ligament; spindle-shaped types, and expanded nerve endings, both rarely found near the root apex. Immunostaining for S-100 protein showed that no lamellated nerve terminals were found in the human periodontal ligament. The region-specific distribution of various nerve terminals demonstrated in this study seems to be suited to effectively receive mechanical stimuli to the teeth from various directions.

Humans↗
PubMed1990

Familial occurrence of moyamoya disease with intracranial hemorrhage--report of two cases.

The authors report an instance of familial moyamoya disease involving a 47-year-old female and her 18-year-old daughter, both of whom initially presented, within a 1-year period, with intracranial hemorrhage. Cerebral angiography showed the typical features of moyamoya disease. The mother, whose disease was more advanced, underwent superficial temporal-middle cerebral artery bypass, with satisfactory results. Human leukocyte antigen typing was performed in both cases. The pertinent literature is reviewed.

Adolescent↗
PubMed1990

[An immunohistochemical study on the response of nerve fibers in the periodontium of rat molars during experimental tooth movement].

It is well known that orthodontic forces induce pain during tooth movement. However there have been few neurohistological studies on sensational periodontal tissue response to orthodontic tooth movement. So we have many unknown problems about reactions of periodontal nerve fibers during tooth movement. The present study deals with the response of nerve fibers in periodontal ligament of rat molar during experimental tooth movement by means of immunohistochemical method for calcitonin gene-related peptide (CGRP). The results obtained in this study were as follows: 1. In control sections, CGRP-immunopositive nerve fibers were observed both around the root apex and in the intermediate region of the periodontal ligament. Although most of those fibers was distributed around the blood vessels, a few nerves were recognized to terminate in the periodontal fibers. 2. At three days after tooth movement, the CGRP-positive nerves gradually increased in number around the blood vessels. After that, the number of CGRP-positive nerves decreased and no difference of distribution of CGRP-positive nerves was observed between the control sections and the experimental sections at seven days. 3. Especially, at three days when active remodeling of alveolar bone was taking place, a few nerve fibers showing CGRP-immunoreactivity were observed to concentrate around osteoclasts or to migrate Howship's lacunae. These findings showed the dynamic changes of CGRP-immunoreactive nerves in the periodontal ligament during tooth movement, and suggested that this reaction of the periodontal nerves might induce pain in patients. In addition to neurotransmitter function, it was supposed that CGRP directly or indirectly effected the cellular elements and surrounding tissues on peripheral organs such as vascular system and osteoclasts.

Animals↗
PubMed1990

[A successfully treated case of aortouretric fistula associated with pelvic exenteration].

A 64-year-old man was hospitalized for massive bleeding from the cutaneous ureterostomy. He had undergone pelvic exenteration with the ureterostomy for rectal cancer invading the bladder five months previously and retrograde ureteric catheters were inserted bilaterally into the ureters. An aortography revealed a pseudoaneurysm of the abdominal aorta in the region transversed by the left ureter. He was successfully treated by en bloc resection of the aortoureteric fistula and the left ureter and repair of the aorta by Dacron patchplasty. Left nephrectomy was also performed because of pyelonephritis. He has had no signs of cancer recurrence or graft infection five years after this operation.

Aorta, Abdominal↗
PubMed1990

[A case report: persistent primitive hypoglossal artery aneurysm].

The authors describe a case of persistent primitive hypoglossal artery aneurysm in a 42-year-old woman who had complained of headache, mainly in the occiput, for 5 days prior to admission. Because of a sudden exacerbation of the headache associated with vomiting, she was hospitalized on July 31, 1988. On admission, a cranial computed tomography scan demonstrated a high density lesion in the basal cisterns which suggested subarachnoid hemorrhage (SAH). Right carotid angiography revealed a persistent primitive hypoglossal artery and an aneurysm arising from this artery at the junction of the posterior inferior cerebellar artery. Bilateral vertebral arteries were shown to be hypoplastic. This was followed by a right suboccipital craniectomy on the 6th hospital day at which time a neck clipping was made. Her postoperative course was uneventful. On discharge on August 22, she was ambulatory and had no neurological deficit except for a mild hoarseness which developed after surgery. Well over one hundred cases of persistent primitive hypoglossal artery aneurysm have been reported. However, as far as we could discern, there have been only 9 cases of persistent primitive hypoglossal artery aneurysm including this present case. Most of the cases had SAH due to the rupture of these aneurysms with favorable outcome after the surgery. In addition, some embryological considerations were made.

Adult↗
PubMed1989

The ultrastructure of Ruffini endings in the periodontal ligament of rat incisors with special reference to the terminal Schwann cells (K-cells).

The Ruffini endings and associated cells in the periodontal ligament of rat incisors were investigated by means of immunohistochemistry for glia-specific S-100 protein and electron microscopy. Numerous Ruffini endings, which were immunoreactive for S-100 protein as well as for neurofilament protein, were distributed in the alveolus-related part of the lingual periodontal ligament. In electron microscopy, the Ruffini endings displayed expanded axoplasmic spines filled with a large number of mitochondria and neurofilaments; some of the spines directly contacted the surrounding collagen fibers via fingerlike projections. The axoplasmic spines and Schwann sheath, for the most part, were covered alternately by single or multiple layers of the basal lamina. Several rounded cells showing S-100 immunoreactivity occurred in the vicinity of the Ruffini endings. The rounded cells associated with Ruffini endings possessed a kidney-shaped nucleus and enveloped the axoplasmic spines with their cytoplasmic processes. From these morphological features, the cells in question were identified as the K-cells described by Everts et al. (1977). These K-cells developed Golgi apparatus and rough endoplasmic reticulum, suggesting active synthesis of proteins. Immunohistochemistry at the electron microscopic level revealed an intense immunoreactivity for S-100 protein in the cytoplasm of the K-cell and led to a conclusion that the K-cells were terminal Schwann cells associated with Ruffini endings, presumably corresponding to the lamellar cells in the inner bulb of sensory corpuscles.

Animals↗
PubMed1989

Quantification of cerebrospinal fluid shunt flow rates. Assessment of the programmable pressure valve.

Shunt placement diverting cerebrospinal fluid (CSF) has been the treatment of choice for hydrocephalus for the past several decades. However, the procedure often requires revisions owing to excessive drainage, low CSF flow rates, or infections within the system. With regard to valve pressure, selection of an appropriate valve for a specific patient prior to surgery is not always a simple task. Further, an optimal valve selected at the time of implantation may no longer be appropriate given changing pathophysiological conditions as time passes. It is thus desirable to provide a single valve in which the pressure may be modified when necessary without revision. A programmable pressure valve (designed by Sophysa of France) comes in one model which accommodates different pressure settings obviating revision when pressure changes are needed. Pressure changes can be achieved externally by means of a special magnet which allows precise adjustments in valve pressure to be made through the scalp. The authors introduce the mechanism and describe the cases treated using this valve.

Adult↗
PubMed1989

Time course of CSF lactate level in subarachnoid haemorrhage. Correlation with clinical grading and prognosis.

Cisternal and/or ventricular cerebrospinal fluid (CSF) and arterial blood lactate and acid-base balance were measured serially in 38 patients with aneurysmal subarachnoid haemorrhage (SAH). Based on daily clinical assessment, the patients and accordingly the samples were divided into two groups according to the grading of the World Federation of Neurosurgical Societies (W.F.N.S.). In cisternal CSF, samples of Grade III-V showed significantly higher lactic acidosis than those of Grade I-II. The time course of lactate and pH in poor prognosis groups had a significant tendency of lactic acidosis, especially on the 5th, 6th, 7th day after SAH. Ventricular CSF lactate increased even without CSF acidosis in Groups III-V. Measurement of CSF lactate, especially from the cisterna magna is useful as an indicator of prognosis and changes of intracranial environment following SAH.

Acid-Base Equilibrium↗
PubMed1989

Atrial natriuretic polypeptide in patients with subarachnoid haemorrhage due to aneurysmal rupture. Correlation to hyponatremia.

Measurement of plasma alpha-humanANP (ANP) and antidiuretic hormone (ADH) in 28 cases with aneurysmal subarachnoid haemorrhage (SAH) was carried out, and then compared with control subjects who were infused with hypertonic saline. In cases with hyponatremia (HN), statistical correlation between control subjects and cases without HN was not evident with regards to ANP and plasma osmolality (Posm), excreted fraction of filtrated sodium (FENa) and urinary Na/K. Furthermore, they secreted supernumerarilly in spite of HN. Cases with HN were further subdivided into two groups, they were those cases with negative total sodium balance at the time of appearance of HN, and those cases without total negative sodium balance. In the former, central venous pressure had a tendency to decrease, however, secretion of ANP and ADH was statistically not different in either groups. It appears that ANP regulated urinary sodium excretion against an osmotic or sodium load acts as a maintenance of homeostasis as an osmotic regulator. Cases with HN in which secretion of ADH was physiological, ANP secreted supernumerarilly in spite of hypoosmonaemia and hypovolaemia. Our findings may contribute to a better understanding of the pathophysiological processes leading to hyponatremia in cases with cerebral disorders, and may help to improve the treatment possibilities.

Adult↗
PubMed1989

The biologic fate of Dacron double velour vascular prostheses--a clinicopathological study.

Thirty-one Dacron double velour prostheses removed from 16 patients were studied microscopically in order to elucidate the changes they underwent following implantation. The process of incorporation was divided into three phases. In the initial phase, immediately following the implantation, the prostheses became surrounded by a fibrin meshwork. In the organizing phase, which sets in 10 weeks after the implantation, there was an external fibrous capsular formation around the initially fibrin-infiltrated grafts. There was also fibroblastic ingrowth and granulation formation among the interstices and the prostheses showed firm adhesion to the surrounding tissues. One year following the implantation, after most of the luminal surfaces had been covered with collagen tissues, the cellular infiltration subsided and the graft passed into the stable phase. Foreign body giant cells and lymphocytes were seen throughout the study period. These prostheses were then compared with other prostheses which do not have velour structures. The nonvelour grafts showed less adhesion to the surrounding tissues. Microscopically, cellular reaction and collagenous ingrowth were also less. The velour surface thus seems to stimulate granulation ingrowth and to contribute to the firm adhesion of the graft to the surrounding tissues. This firm adhesion enhances resistance to infection and is considered safer in case of suture aneurysm formation.

Aorta↗