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Biomedical subjects

S Miyachi

Publications and source records attributed to S Miyachi.

At least 55 records · Page 3Linked to original sources
PubMed1997

Endovascular stenting of a traumatic dissecting aneurysm of the extracranial internal carotid artery--case report.

A 57-year-old male presented with a traumatic dissecting aneurysm of the distal, extracranial internal carotid artery (ICA). Stent placement resulted in complete occlusion of the aneurysm and preservation of the carotid blood flow. He also had an atherosclerotic stenosis of the ipsilateral middle cerebral artery, which was uneventfully treated by angioplasty 3 months after stent placement. Endovascular reconstruction of the ICA with a stent may be the best way to occlude dissecting aneurysms, especially in patients who cannot tolerate ICA occlusion, are at risk from delayed ischemia, or have wide-necked or multiple aneurysms.

Aortic Dissection↗
PubMed1996

Amino acid sequence homology between N- and C-terminal halves of a carbonic anhydrase in Porphyridium purpureum, as deduced from the cloned cDNA.

Carbonic anhydrase (CA) from Porphyridium purpureum, a unicellular red alga, was purified >209-fold to a specific activity of 1,147 units/mg protein. cDNA clones for this CA were isolated. The longest clone, comprising 1,960 base pairs, contained an open reading frame which encoded a 571-amino acid polypeptide with a calculated molecular mass of 62,094 Da. The N- and C-terminal halves of the putative mature Porphyridium CA have amino acid sequence homology to each other (>70%) and to other prokaryotic-type CAs. Both regions contain, at equivalent positions, one set of three possible zinc-liganding amino acid residues conserved among prokaryotic-type CAs. CA purified from Porphyridium contained two atoms of zinc per molecule. We propose that the Porphyridium CA has evolved by duplication of an ancestral CA gene followed by the fusion of the duplicated CA gene. The CA truncated into the putative mature form was overexpressed in Escherichia coli, and the expressed protein was active. Clones expressing separately the N- and C-terminal halves of the CA were constructed. CA activity was present in extracts of E. coli cells expressing the N-terminal half, while no detectable activity was found in cells expressing the C-terminal half.

Amino Acid Sequence↗
PubMed1996

Endovascular occlusion of intracranial aneurysms of the posterior circulation: comparison of balloons, free coils and detachable coils in 38 patients.

We treated 38 patients with 39 aneurysms of the posterior circulation by an endovascular technique using balloons, free coils or Guglielmi detachable coils (GDC) from 1986 to May 1993. The patients ranged in age from 10 to 71 years. Subarachnoid haemorrhage was the most frequent presentation (29 patients), followed by mass effect (5 patients) and epilepsy (2 patients). Treatment consisted of embolisation of the aneurysm with preservation of the parent vessel (in 29) or occlusion of the parent vessel (in 5). Multiple procedures were performed in 12 patients (32%, maximum 3 embolisations, total 17 treatments), because of incomplete initial aneurysm occlusion (in 8 cases) or re-opening of the aneurysm (in 9). Treatment could not be achieved in 5 patients. Good to excellent aneurysm occlusion was obtained in 28 patients (72%). Little or no neurological impairment occurred in 31 patients (82%). Complications related to treatment (11 patients, 29%) included 4 cases of transient cerebral ischaemia, 7 of stroke resulting in minimal neurological impairment (in 5), severe impairment (in 1) and one death. There were 6 patients who died, of rebleeding from the same aneurysm (2), basilar stroke (1) and unrelated causes (3). Comparison of the different occlusion techniques showed that the best angiographic results were obtained with balloons (good to excellent aneurysm occlusion was obtained in 17 of 22 patients treated) and the GDC (12 of 13 patients), and that less good results were given by free coils (4 of 9 patients). Complications related to treatment were fewest in patients treated with GDC (1 of 16 treatments, including multiple procedures) or free coils (2 of 12 treatments) and were more frequent with balloons (6 of 27 treatments). All five treatment failures occurred with balloon embolisation, whereas treatment was possible in all cases treated with free coils or GDC.

Adolescent↗
PubMed1996

Anticipatory saccades in sequential procedural learning in monkeys.

1. In a preceding paper we examined the short-term and long-term processes of learning of sequential procedures in monkeys. We now report that the pattern of eye movements changed along with the long-term learning. 2. The monkey's task was to press five consecutive pairs of target buttons (indicated by illumination) in the correct order for every pair, which the monkey had to find by trial and error (2 x 5 task). The whole sequence was called the "hyperset"; each pair was called the "set." 3. Initially, the saccade toward the correct target occurred after illumination of the targets (visually guided saccade). After sufficient learning, the saccade tended to occur before the target illumination (anticipatory saccade). This was true only for the hyperset that had been learned. 4. The likelihood of anticipatory saccade increased gradually over 20-30 days of practice of the particular hyperset. The time course was similar to how the hand learned (button press latency). 5. The monkeys were required to use the same hand for each hyperset throughout learning, except when we asked them to use the opposite hand. The nearly perfect performance due to the extensive practice was then deteriorated by the use of the opposite hand. We found, in addition, that anticipatory saccades became much less frequent. This finding suggests that critical for the skilled performance was the combination of the eyes and the side of the hand that was used for the practice of a given sequence.

Animals↗
PubMed1996

Arteriovenous malformations of the corpus callosum--radioanatomic study and effectiveness of intranidus embolization.

Forty-three patients with arteriovenous malformations (AVMs) of the corpus callosum treated by embolization were reviewed. The following clinical and radioanatomic characteristics were found: 84% (36 patients) presented with intracranial hemorrhage, 43% (20 nidi) of the lesions were located in the posterior half of the corpus callosum, multiple nidi were more frequent (21%) than expected, 27 nidi (59%) were fed by branches of both the anterior and posterior cerebral arteries, AVMs mainly drained into the internal cerebral vein and/or interhemispheric superficial veins, and 19 (41%) had both draining pathways, 10 patients (23%) had impaired drainage through the straight sinus due to dysplasia. Staged embolization was performed in 245 feeders. Curative occlusion (more than 95%) was obtained in 17 patients (40%) and considerable occlusion (more than 75%) in 33 patients (77%). Large and giant, diffuse-type, and multifocal AVMs were difficult to completely embolize. Complications associated with embolization occurred in six patients, mostly during the first 5 years. Only two patients had a permanent deficit related to a complication. Overall morbidity and mortality were 7% and 2%, respectively. Nine patients were referred for stereotactic radiosurgery, three of whom were completely cured and five patients have not been assessed. Most AVMs in the corpus callosum are supplied by multi-axial feeders, so multi-target intranidus embolization is very important to prevent the development of other feeders secondary to the hemodynamic shift. Combined therapy using maximum embolization and subsequent radiosurgery may be the most effective method to treat AVMs in the corpus callosum.

Adolescent↗
PubMed1995

Learning of sequential movements in the monkey: process of learning and retention of memory.

1. To characterize procedural learning and memory, we devised a behavioral paradigm that allows us to examine the process of learning of new procedures, repeatedly and without serious difficulties for primate subjects. We trained two monkeys to perform a sequential button press task. Upon pressing of a home key, 2 of 16 (4 x 4 matrix) light-emitting diode (LED) buttons (called "set") were illuminated simultaneously, and the monkey had to press them in a predetermined order that he had to find out by trial-and-error. A total of five sets (called "hyperset") was presented in a fixed order for completion of a trial; an error at any set aborted the trial. A given hyperset was repeated as a block of experiment until 20 successful trials were performed. Monkeys PI and BO experienced 313 and 92 hypersets, respectively. Most of these hypersets were experienced only once (1 block of experiment); the others (28 hypersets for monkey PI and 14 hypersets for monkey BO) were chosen for extensive practice. 2. The learning, indicated as the decrease in the number of trials to criterion and the decrease in the performance time, proceeded at three levels: 1) short-term and sequence-selective learning that occurred by repeating a particular hyperset during a block of experiment; our monkeys learned, to some degree, to perform a new hyperset within a short period (< 5 min); 2) long-term and sequence-selective learning that took place for each hyperset across days; by daily practice, they further improved their skills for performing the particular hyperset; and 3) long-term and sequence-unselective learning that was indicated by the improvement of performance for new hypersets; the monkeys were required to learn many hypersets, each just once (a block of trials), in which they performed gradually better with more experiences in the 2 x 5 task. 3. To examine whether the memory was retained for a long period, we had the monkey learn 12 hypersets sufficiently, then we stopped the training and retested them after 1 or 6 mo. After the 1-mo interruption the performance was significantly better than that for new hypersets. After the 6-mo interruption the performance was not different from new hypersets in terms of the number of trials but was significantly better than new hypersets in terms of the performance time. The results suggest that motor memory (measured by performance time) can be retained longer than procedural memory (measured by the number of trials).

Animals↗
PubMed1995

Acute revascularization for bihemispheric anterior cerebral artery thrombosis--case report.

A 65-year-old male presented with rapidly progressive paraparesis and akinetic mutism due to occlusion of the bihemispheric anterior cerebral artery (ACA). He was treated by intra-arterial thrombolytic therapy but reocclusion of the arteriosclerotic lesion occurred. Bilateral superficial temporal artery (STA)-ACA anastomoses achieved lasting neurological improvement. Bilateral STA-ACA anastomoses are quite effective to prevent ischemia of the bilateral ACA territories.

Aged↗
PubMed1995

[Systemic necrotizing vasculitis with pulmonary hemorrhage and gastrointestinal bleeding].

A 61-year-old man was admitted to our hospital with pain and weakness in both lower legs. Eosinophil count was abnormally high (6800/mm3). Chest X-ray film revealed multiple infiltrates in both lung fields. A specimen obtained by transbronchial lung biopsy demonstrated pulmonary hemorrhage. Vasculitis syndrome was suspected and 1 g per day of methylprednisolone was administered for 3 days. Pulmonary infiltrates quickly disappeared, but 2 weeks later massive intestinal hemorrhage occurred. Emergency ilectomy was done, but the patient died of bleeding from other intestinal lesions. Microscopic examination of the resected ileum revealed mucosal ulceration and necrotizing vasculitis in small arteries. This case is important in that vascular occlusion and ischemia progressed soon after vascular inflammation was relieved by administration of corticosteroid hormone.

Churg-Strauss Syndrome↗
PubMed1994

Cerebellar stroke due to vertebral artery occlusion after cervical spine trauma. Two case reports.

The authors report two cases of cerebellar infarction due to vertebral artery (VA) occlusion resulting from cervical spine trauma. In one patient with dens and C2 body fracture, the left VA was occluded, resulting in a left cerebellar infarction. The second patient, with a subluxation of C4 on C5, presented with cerebellar swelling and infarction along with acute hydrocephalus secondary to bilateral vertebral artery occlusion. Because vertebral artery injuries with cervical trauma are rarely symptomatic, they can be easily overlooked. Bilateral or dominant vertebral artery occlusion, however, may cause rapid and fatal ischemic damage to the cerebellum and brain stem. Rapid recognition and optimal treatment for this injury depends on early vertebral artery angiography.

Angiography↗
PubMed1994

A study of dose escalation of teniposide (VM-26) plus cisplatin (CDDP) with recombinant human granulocyte colony-stimulating factor (rhG-CSF) in patients with advanced small cell lung cancer.

A dose escalation study of teniposide (VM-26) plus cisplatin (CDDP) was carried out using recombinant human granulocyte colony-stimulating factor (rhG-CSF) in 46 previously untreated patients with advanced small cell lung cancer (SCLC). The dose of CDDP was 80 mg/m2/day intravenously (i.v.) (day 1) and VM-26 was escalated from 60 mg/m2/day to 80, 100 and 120 mg/m2/day i.v. x 5 days for four cycles. The dose of rhG-CSF was 90 micrograms/m2/day subcutaneously for 13 days. The feasibility of the regimen at the starting dose level of VM-26 with or without rhG-CSF was initially examined in 10 patients chosen through random allocation. WHO grade 4 neutropenia was observed in 17% (three out of 18 courses) of patients in the rhG-CSF group and in 63% (12 out of 19 courses) of the control group (P < 0.01). The number of patients with febrile episodes (> 38 degrees C) over the four courses of chemotherapy was 1 in the rhG-CSF group and 4 in the control group. According to these results, all 36 patients received rhG-CSF in the dose escalation stage. The incidence of WHO grade 4 neutropenia at the dose levels of 60, 80, 100 and 120 mg/m2/day of VM-26 was 66, 57, 76 and 85%, respectively (P > 0.1). The incidence of grade 4 thrombocytopenia was 19, 31, 18 and 46%, respectively (P > 0.1). The overall response rate was 100% in patients with limited stage SCLC and 83% in patients with extensive stage SCLC. The actual administered VM-26 dose per week at the dose level of 100 mg/m2/day was 1.6-fold higher than the planned starting dose (60 mg/m2/day) per week. At the dose level of 120 mg/m2/day, 50% of patients developed WHO grade 4 leucopenia, which lasted longer than 1 week and 67% of the patients had WHO grade 3 or 4 diarrhoea. At this same dose, all patients had at least one febrile episode (> 38 degrees C), and 1 patient died of cerebral bleeding with severe thrombocytopenia. The median survival time of all patients was 451 days (411 days, extensive disease; 497 days, limited disease). VM-26 plus CDDP with rhG-CSF was active in previously untreated patients with SCLC. The recommended dose of VM-26 in combination with CDDP for a phase II study is 100 mg/m2/day for 5 days with rhG-CSF support.

Adult↗
PubMed1994

[A case of pulmonary alveolar proteinosis with elevated serum angiotensin-converting enzyme activity].

A 45-year-old man with diffuse infiltrates on the chest X-ray film was admitted to the hospital. At first, sarcoidosis was suspected due to the elevated serum angiotensin-converting enzyme (ACE) activity. Transbronchial lung biopsy and bronchoalveolar lavage, however, did not lead to that diagnosis. Pulmonary alveolar proteinosis (PAP) was diagnosed after an open lung biopsy. The diffuse infiltrates on his chest X-ray film diminished spontaneously. Two years later, diffuse infiltrates increased again with an elevated serum ACE activity. In this case, it seemed that the severity of PAP was associated with serum ACE activity. We review the literature on the relationship between serum ACE activity and dysfunction of alveolar macrophages in PAP.

Humans↗
PubMed1993

Structural analysis of periplasmic carbonic anhydrase 1 of Chlamydomonas reinhardtii.

Periplasmic carbonic anhydrase 1 of the unicellular green alga Chlamydomonas reinhardtii is a heterotetrameric glycoprotein consisting of two large subunits and two small subunits [Kamo, K., Shimogawara, K., Fukuzawa, H., Muto, S. & Miyachi, S. (1990) Eur. J. Biochem. 192, 557-562]. The cDNA sequence showed that the two subunits are cotranslated as a 377-amino-acid precursor polypeptide (41.6 kDa) consisting of an N-terminal 20-amino-acid signal peptide, a large subunit (35.6 kDa) and a small subunit (4.1 kDa) [Fukuzawa, H., Fujiwara, S., Yamamoto, Y., DionisioSese, M. L. & Miyachi, S. (1990) Proc. Natl Acad. Sci. USA 87, 4383-4387]. In the present study, amino-acid-sequence analysis of the carbonic anhydrase 1 was carried out to determine the sites of disulfide bonds and N-glycosylation and the C-terminal amino acid of the large subunit. Disulfide bonds were detected between Cys21 and Cys21, Cys61 and Cys264, Cys194 and Cys198, and Cys296 and Cys351 in the amino acid sequence deduced from the cDNA. Cys21 and Cys21 link two large subunits and Cys296 and Cys351 link a large subunit to a small subunit. Thus, the holoenzyme is constructed of two disulfide-bound large subunits, each of which joins to a small subunit by a disulfide bond. The C-terminal amino acid residue of the large subunit was determined as Ala305. This indicates that the peptide consisting of 35 amino acid residues between the large and the small subunit is deleted from the precursor during maturation, since the N-terminus of the small subunit is Ala341. Three potential N-glycosylation sites in the large subunit were all glycosylated.

Amino Acid Sequence↗
PubMed1993

Contribution of meningeal arteries to cerebral arteriovenous malformations.

We studied 52 patients with cerebral arteriovenous malformations (AVMs) by selective angiography and found that half received supply from meningeal branches of the external carotid artery. The frequency of meningeal arterial contribution was significantly higher in superficial AVMs, especially in the temporal, parietal and occipital regions. Larger lesions and higher shunt with steal phenomena on angiography were other factors favouring a meningeal arterial contribution. Diffuse AVMs with pial arterial networks around the nidus commonly received meningeal blood supply. In the past, meningeal feeders have been thought to be congenital, but this study suggests that they may develop during growth of the AVM.

Adolescent↗
PubMed1993

Dural carotid cavernous sinus fistula presenting as isolated oculomotor nerve palsy.

We report five patients with dural carotid cavernous sinus fistula presenting with isolated oculomotor nerve palsy. All patients were older women with a fistula derived from the internal carotid artery, who had early filling of the supero-posterior cavernous sinus, followed by drainage posteriorly into the inferior petrosal sinus, with low shunt flow. The hypothesized pathogenesis was nerve compression by an expanding sinus, or ischemic neuropathy secondary to venous congestion or arterial steal. Dural carotid cavernous sinus fistula must be considered in patients presenting with isolated oculomotor nerve palsy.

Aged↗
PubMed1993

Isolation and characterization of a major allergenic component (gp55) of Aspergillus fumigatus.

IgE class antibodies specific for antigens in a water-soluble extract of Aspergillus fumigatus (strain NHL-5759) were analyzed by immunoblotting with sera from patients with allergic bronchopulmonary aspergillosis. All the sera tested were reactive with a major 50 to 60 kd protein in the extract. This allergen, designated gp55, was purified by gel filtration and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antigen was found to be present in the water-soluble extract in the form of a complex composed of approximately eight molecules of gp55. The carbohydrate and phosphate content of the purified antigen were 23.1% and 0.46%, respectively. The molar ratio of mannose to galactose residues was 2.76:1, and the protein was glycosylated predominantly with N-linked oligosaccharides. The serologic activity of the gp55 antigen was abolished by treatment with nonspecific protease (Pronase) but not by treatment with sodium metaperiodate or endoglycosidases. Thus the major antigenic site of the glycoprotein is located within its peptide moiety. The antigen itself displayed no chymotryptic or tryptic activity. The amino acid sequence of the 20 N-terminal residues of the antigen (ATPHEPVFFSWDAGAVTSFP) is different from that of any other protein previously reported.

Amino Acid Sequence↗
PubMed1993

Evaluation of pressure changes in feeding arteries during embolization of intracerebral arteriovenous malformations.

The pressure in 47 arteries feeding 21 arteriovenous malformations (AVM's) was investigated during transarterial embolization using a Tracker-18 microcatheter. On average, systolic pressure increased by 22 mm Hg. In AVM's with single or few feeders, embolization was usually achieved well; in contrast, giant AVM's with multiple feeders and a large arteriovenous shunt were poorly embolized. However, large AVM's with well-demarcated components may be reduced by embolization to an appropriate size for surgery or stereotactic radiation therapy. It was found that the feeding artery pressure increased significantly more in well-embolized than in poorly embolized cases. Measurements of the feeding artery pressure clarified the hemodynamics of AVM's and facilitated more successful embolization.

Adolescent↗