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Biomedical subjects

T Asakura

Publications and source records attributed to T Asakura.

At least 217 records · Page 12Linked to original sources
PubMed1992

Characterization of low-temperature-plasma treated silk fibroin fabrics by ESCA and the use of the fabrics as an enzyme-immobilization support.

Bombyx mori silk fibroin fabrics were treated with low-temperature-plasma using various gases. Alkaline phosphatase was immobilized onto the fabrics using the CNBr method. The enzyme activity was much improved by plasma treatment, especially when both O2 and CF4 were used. Using the ESCA technique it was found that the activities of the immobilized enzyme were strongly correlated with the C1s peak intensities of the atomic group -C-O-CF3. The apparent Michaelis constant for the enzyme decreased with increasing amounts of -C-O-CF3.

Alkaline Phosphatase↗
PubMed1992

Prostaglandin synthesis and accumulation by porcine ciliary epithelium.

The activity to synthesize prostaglandins (PGs*) from arachidonic acid [i.e. cyclooxygenase (CO) activity] was compared between nonpigmented epithelial (NPE) cells and pigmented epithelial (PE) cells from porcine ciliary processes. PG synthesizing activities were about the same (0.58 and 0.52 pmol per mg protein per 15 min for NPE and PE, respectively), and inhibited by indomethacin and anti-CO antibody but not by nordihydroguaiaretic acid. By immunogold labeling, CO immunoreactivity was found both in NPE and PE. The present results and the previous observation on higher PG omega/omega-1 hydroxylation activities in NPE than in PE, taken together, suggest that controlled synthesis and inactivation of PGs may have a role in functions of NPE. When PGE2 was incubated with NPE or PE, NPE cells accumulated PGE2 more actively than did PE cells. PG uptake by the NPE cells may prevent aqueous and vitreous PGs from entering the anterior chamber and causing anterior uveitis.

Animals↗
PubMed1992

Study of chronic schizophrenics using 31P magnetic resonance chemical shift imaging.

Phosphorus-31 chemical shift imaging showed regional abnormalities of in vivo 31P NMR spectra in the brains of chronic schizophrenic patients. In the left temporal region, the level of % phosphodiesters (PDE) was increased and the level of % gamma alpha beta-ATP (obtained by summation of gamma-ATP, alpha-ATP, and beta-ATP) was decreased. In the basal ganglia, the levels of % PDE were decreased and the level of % phosphomonoesters was increased. The levels of % gamma alpha beta-ATP were increased in the right basal ganglia. The level of % phosphocreatine was decreased in the frontoparietal region. These findings may represent different patterns of dysfunction of membrane phospholipid bilayers and high-energy phosphate metabolism in the specific cerebral regions.

Adenosine Triphosphate↗
PubMed1992

Recurrent hemoptysis due to aortobronchopulmonary fistula of false aortic aneurysm associated with repair of rupture of the sinus of Valsalva.

A 54-year-old man presented with recurrent hemoptysis of one year duration. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a saccular aneurysm of the ascending aorta. The aneurysm was intraoperatively found to have formed on the superior surface of the site of aortotomy suture placed during previous repair of rupture of the sinus of Valsalva and to have a fistulous communication to the lung. CT and MRI were very useful in the diagnosis of the aneurysm as the cause of hemoptysis.

Aortic Aneurysm↗
PubMed1992

Coexistence of extracranial internal carotid artery aneurysm and multiple intracranial aneurysms--case report.

A rare case of extracranial internal carotid artery (ICA) aneurysm coexisting with intracranial multiple aneurysms in a 64-year-old female is reported. The three intracranial aneurysms were clipped uneventfully by two-stage craniotomies. The extracranial ICA aneurysm at the infratemporal region was excised through a high cervical route and ICA was reconstructed by an end-to-end direct anastomosis. Ours is the first case reported of extra- and intracranial aneurysms surgically treated successfully.

Aneurysm↗
PubMed1992

Traumatic internal carotid artery occlusion--case report.

A 20-year-old male was admitted comatose immediately after a motorcycle accident. Initial computed tomography demonstrated traumatic subarachnoid hemorrhage, and the diagnosis of traumatic internal carotid artery occlusion was established by angiography. Conservative management improved his symptoms, but eventually he died from delayed traumatic apoplexy. Traumatic internal carotid artery occlusion is relatively rare, but is serious and requires early diagnosis and treatment. For patients with severe head trauma and vascular occlusion, anticoagulants are contraindicated, and frequent follow-up angiography is recommended.

Adult↗
PubMed1992

Absorption and metabolism of pyridoxamine in mice. II. Transformation of pyridoxamine to pyridoxal in intestinal tissues.

The absorption of pyridoxamine from the intestine of the mouse was studied in whole animals. [3H]Pyridoxamine was orally administered and the distribution of isotope between the six recognized forms of vitamin B6 was determined in portal blood after the administration. When small doses (1.4 or 14 nmol) were administered, labeled pyridoxamine could hardly be found in the portal blood, although labeled pyridoxal and pyridoxal phosphate were found in the same blood. However, when a large amount (46 or 140 nmol) was given, a significant amount of labeled pyridoxamine was found with labeled pyridoxal and pyridoxal phosphate in the portal blood. These results suggest that a physiological dose of pyridoxamine is rapidly transformed to pyridoxal in the intestinal tissues and then released in the form of pyridoxal into the portal blood.

Administration, Oral↗
PubMed1992

[Transcranial magnetic stimulation of the facial nerve].

It was the object of the present study to determine whether transcranial facial nerve stimulation using a magnetic coil can be clinically applicable, and to find the site where the facial nerve is best stimulated. A magnetic coil was placed over the parieto-occipital skull of the subjects for stimulation, and the facial nerve was electrically stimulated in its intracranial and peripheral courses. Then an electromyogram was recorded from the nasalis muscle of the face on the stimulated side. In 9 healthy volunteers, 18 facial nerves received magnetic and electric stimuli in the peripheral region, and the actual site of stimulation was estimated from the conduction velocity of the nerve. The conduction velocity was 56.6 +/- 4.8 m/s, and the latency between CMAPs for electric at the magnetic stimuli to the posterior tragus was 1.23 +/- 0.21 ms. Therefore, the position stimulated by magnetic coil was estimated to be 70.0 +/- 11.4 mm central to the posterior tragus, i.e., near the root exit zone. In two patients undergoing surgery in the cerebellopontine angle, transcranial magnetic stimulation and electrical stimulation of the intracranial facial nerve were compared intraoperatively. The CMAP produced by transcranial magnetic stimulation coincided closely with that produced by direct electrical stimulation of the root exit zone. Thus, the facial nerve was stimulated at the root exit zone, and this method could be expected to be useful for evaluation of disorders of the intracranial facial nerve.

Adult↗
PubMed1992

[Problems and prevention in using arterial grafts for coronary artery bypass grafting].

The arterial graft has proved to be superior to the saphenous vein graft for coronary bypass grafting (CABG), because of its excellent long-term patency. However, there mains controversial on the choice of the arterial grafts. Six hundreds and twenty seven patients who had CABG using both arterial grafts and saphenous vein grafts, operated upon over 11-years period between 1980 and 1991, have been analysed. Some disadvantages and complications associated with the use of arterial grafts were demonstrated in our series. We discussed, the flow capacity, myocardial protection and postoperative complications in using arterial grafts for CABG.

Aged↗
PubMed1992

[Coronary artery bypass surgery in the elderly].

In recent years it has become apparent that the number of persons 70 years of age or older is increasing. Between June, 1980, and December, 1990, 75 patients 70 years of age and older (range, 70-79 years; mean 73.1) underwent isolated coronary artery bypass grafting (CABG). During this same interval, 507 patients less than 70 years old underwent isolated CABG. Preoperative status in the elderly showed a significantly greater prevalence of women, urgent or emergent operation, triple vessel disease and diabetes. Operative mortality was higher among the elderly compared with the younger patients (p < 0.05). The increased frequency of urgent or emergent operation in the elderly was associated with postoperative complications. Major complications related CABG in the elderly were serious cerebrovascular accidents and low cardiac output syndrome. In order to improve the results of CABG in the elderly, it is essential to perform the elective operation following careful evaluation of both cardiac function and central nervous system.

Aged↗
PubMed1992

[Transorbital penetrating brain injury].

Transorbital penetrating brain injury is rare during this time of peace. In our paper, we reported seven cases of these injuries and discussed the mechanism and treatment of intracranial complications. Transorbital penetrating brain injuries were caused by thin, long and relative hard objects such as chop-stick (case 3), pencil (case 6), bamboo stick (case 1, 2, 7) and a piece of metal (case 4, 5). CT scan, MRI and angiography demonstrated a large variety of intracranial complications. For instance, intracerebral hematoma, cerebral contusion, intraventricular hemorrhage, pneumocephalus, brain stem injury and carotid cavernous sinus fistula. We had no case of infectious complications such as meningitis and brain abscess. If the direction of the injuring object runs parallel to the orbital roof, it penetrates the cranial cavity commonly via the superior orbital fissure or the optic canal, which routes provide direct access without bone fracture. This direction will cause critical intracranial complications such as CCF or brain stem injury. If the injuring object runs upward and across the orbital roof which has thin bone and therefore offers little resistance, the frontal lobe will be easily damaged, and it will cause intracerebral hematoma. But the prognosis for this type of injury is not so poor because we can easily remove the hematoma and the foreign body. With our treatment policy of "pull and see", all our cases but one recovered well. The one exception was a case in which a large intracerebral hematoma was over-looked in an ophthalmological clinic. This patient died. Nowadays, CT scan and MRI give clear information about the anatomical location of injuring objects and intracranial complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Selective jugular cannulation for hypothermic retrograde cerebral perfusion in thoracic aortic operations (reverse over the wire-catheter method)].

We have employed hypothermic retrograde total body perfusion via the caval cannulae as a supportive measures to protect the brain and other systemic organs in operations for aortic arch aneurysms or acute aortic dissection. But occasionally unsatisfactory results ensued, because competent valves located in the internal jugular vein near the jugulo-subclavian junction may block retrograde blood flow to the brain from the caval cannula. To cope with this problem, we designed an easy and safe method to cannulate the internal jugular vein transatrially utilizing guidewire and central venous catheter, and thereafter we have used this technique clinically and obtained good results.

Aorta, Thoracic↗
PubMed1991

Follow-up of asymptomatic HTLV-I carriers among blood donors in Kyushu, Japan.

We examined mortality from adult T-cell leukemia/lymphoma (ATL/ATLL) and other diseases alleged to be associated with human T-lymphotropic virus type I (HTLV-I) among anti-HTLV-I antibody-positive blood donors in Kyushu, Japan. During 1984-87, a total of 3,991 blood donors aged 40 years or over were followed from the date of donation to the date of death or the end of the study. Crude mortality rates from ATL (with 95 percent confidence intervals) were 68 per 100,000 (13-202) for males and 36 per 100,000 (3-132) for females. The rates were underestimated by approximately 50 percent because of self-selection and short observation periods. Neither death rates from other cancers nor death rates from all cancers were elevated.

Adult↗
PubMed1991

Concomitant carriage of hepatitis B virus and human T-lymphotropic virus type I among blood donors in Kitakyushu, Japan.

The seroprevalence of hepatitis B surface antigen (HBsAg) by gender and age and of human T-lymphotropic virus type I (HTLV-I), and their concomitant carriage was examined among blood donors at the Kitakyushu Red Cross Blood Centre in the fiscal year of 1988. The positive rates of HBsAg among males were consistently higher than those of females; the peaks were detected in male donors aged 30-39 years and in females aged 40-49 years. Declining seropositive rates in individuals aged 50 years or over were observed for both genders. Self-selection due to chronic HBV infection may partly account for such tendencies. On the other hand, the prevalence rates of anti-HTLV-I antibodies among males were uniformly lower than those of females, which must be attributable to male-to-female transmission of HTLV-I via sexual contact. Elevated positive rates in proportion to age were noted for both genders, which may be explained in part by birth cohort effect. The seropositive rates of HBsAg among HTLV-1 carriers were not statistically different from those of non-HTLV-I carriers. Conversely, the prevalence of antibodies to HTLV-I was unrelated to the status of seropositivity of HBsAg.

Adult↗
PubMed1991

A new surgical approach to tricuspid annuloplasty: possibility of an extracardial suture technique "AV-gathering".

A new extracardiac method of annuloplasty for tricuspid insufficiency was performed on cadavers and in dogs. This procedure effectively produced valvular ring cerclage without causing any decrease in right coronary arterial blood flow. In the animal model, using this approach experimental tricuspid stenosis was successfully attempted. The details of the procedure are reported in this article.

Animals↗