Search PubMed⌕ Search

Biomedical subjects

T Asakura

Publications and source records attributed to T Asakura.

At least 253 records · Page 14Linked to original sources
PubMed1990

Effect of gabaculine on metabolism and release of gamma-aminobutyric acid in synaptosomes.

Synaptosomes isolated from mouse brain were incubated with [14C]glutamate and [3H]gamma-amino-butyric acid ([3H]GABA), and then [14C]GABA (newly synthesized GABA) and [3H]GABA (newly captured GABA) in the synaptosomes were analysed. (1) the [3H]GABA was rapidly degraded in the synaptosomes, (2) when the synaptosomes were treated with gabaculine (a potent inhibitor of GABA aminotransferase), the degradation of [3H]GABA was strongly inhibited, (3) the gabaculine treatment brought about a significant increase in Ca2(+)-independent release of [3H]GABA with no effect on Ca2(+)-dependent release, (4) no effects of gabaculine on degradation and release of [14C]GABA were observed. The results indicate that there are at least two pools of GABA in synaptosomes and support the possibilities that GABA taken up into a pool which is under the influence of GABA aminotransferase is released Ca2(+)-independently and that GABA synthesized in another pool which is not under the influence of GABA aminotransferase is released Ca2(+)-dependently.

4-Aminobutyrate Transaminase↗
PubMed1990

Flow patterns and spatial distribution of atherosclerotic lesions in human coronary arteries.

To investigate the potential role of fluid mechanical factors in the localized genesis and development of atherosclerotic lesions in humans, the exact anatomic locations of atherosclerotic lesions and the flow patterns at such sites in left and right human coronary arteries were studied in detail by flow visualization and high-speed cinemicrographic techniques using five isolated, transparent human coronary arterial trees prepared postmortem. It was found that atherosclerotic plaques and wall thickenings in left and right coronary arteries were localized almost exclusively on the outer wall of one or both daughter vessels at major bifurcations and T-junctions, which left the flow-divider free of lesions, and along the inner wall of curved segments. When flow patterns in such vessels were studied in detail, it was discovered that these sites were where flow was either slow or disturbed with the formation of slow recirculation and secondary flows and where wall shear stress was low. The results indicate that the major hemodynamic factors directly related to the localization of atherosclerotic plaques and wall thickenings in the human arterial system are the low fluid velocity and the resultant low shear stress that acts on the vessel wall.

Adolescent↗
PubMed1990

Cerebral energy metabolism and oxygen state during hypoxia in neonate and adult dogs.

The relationship between a noninvasive determination of relative oxygen saturation of Hb circulating in brain tissue (StO2) and energy metabolism was investigated with respect to age [dogs in three age groups (0 to 6-d-old, 7- to 21-d-old, and adults)] and to severity of brain hypoxia using double beam spectroscopy of Hb deoxygenation and nuclear magnetic resonance spectroscopy of energy metabolism. The in vivo oxy-Hb dissociation was determined from the relationship between StO2 curve in the adult dog brain and sagittal sinus oxygen partial pressure during graded hypoxemia and found to be sigmoidal with an oxygen dissociation constant of 26.6 mm Hg. This agreed with an in vitro determination for oxygen dissociation constant of 28.2 mm Hg in adult dog red cells. The arterial oxygen pressure at which brain StO2 was reduced by 50% was shifted toward the right with increasing age (22.2, 33.8, and 40.8 mm Hg, respectively). This correlated with an in vitro oxygen dissociation constant of red cell Hb of 17.0, 22.3, and 28.2 mm Hg in the three age groups, respectively. The phosphocreatine-inorganic phosphate ratio (PCr/Pi) was used to relate changes in cellular energy metabolism during hypoxia with changes in StO2. There was no change in PCr/Pi when StO2 had decreased to 50% of the control value. However, when the brain StO2 had decreased to between 7 and 15%, a reduction of PCr/Pi to 50% of the normoxic value occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

Unusual intra- and extracranial arteriovenous communication--case report.

The authors report an unusual case of arteriovenous communication between extracranial and intracranial vessels, accompanied by incidentally detected bilateral arachnoid cysts of the middle cranial fossa. A 52-year-old male was admitted with a sudden onset of headache, vomiting, and conjunctival hyperemia of the right eye followed by progressive chemosis and proptosis. He had undergone a craniotomy for hypertensive right putaminal hemorrhage 4 months previously. Angiography showed the main feeding artery to be the superficial temporal artery and the draining veins to be the superficial Sylvian veins and the basal vein of Rosenthal. Partial obstruction of the right cavernous sinus was also shown. At surgery, granulation tissue continued to the dura mater through the skull aperture of previous craniotomy and adhered to the underlying damaged cerebrum. The extremely unusual nature of the communication, the operative findings, and the atypical fistulous figures suggested that communication had occurred postoperatively via newly generated vessels in granulation tissue.

Arachnoid Cysts↗
PubMed1990

[Arachnoid cyst of the fourth ventricle. Case report].

A 65-year-old female was admitted because of progressive vertigo, truncal ataxia, and unsteadiness of gait for the past 6 years. Computed tomography (CT) and magnetic resonance imaging revealed a non-enhanced, large midline cyst in the posterior fossa and slightly dilated lateral and third ventricles. Metrizamide CT cisternography showed no communication between the cyst and the subarachnoid space. Suboccipital craniectomy, laminectomy of the atlas, and membranectomy of the cyst were performed. On light microscopic examination, the cyst wall was composed of arachnoid cells and connective tissues. Thus, this lesion was not an epithelial cyst but an arachnoid cyst occupying the fourth ventricle. An arachnoid cyst of the fourth ventricle is extremely rare, and only two cases were previously reported.

Aged↗
PubMed1990

[A six-year follow-up study of childhood behavior problems].

In order to study the outcome of childhood behavior problems and to investigate relationships between those behavior problems and mental health problems in later years, a survey which was conducted in 1977 was repeated after six years. Subjects were randomly selected children aged from three to seven years living in Bunkyo-ku in Tokyo in 1977. Out of 279 children, responses to the questionnaire were obtained for 201 children, with 39 refusing to co-operate and 39 having left the area. The main results were as follows: 1. Comparison of prevalence rates of individual behavior problems occurring in early childhood (from 3 to 7 years old), showed that behaviors such as overactivity, "difficult to control", persistence, stubbornness and poor relations with unfamiliar persons decreased rapidly with age. On the other hand, hypoactivity, withdrawal and shyness increased. For problems occurring in late childhood (from 9 to 13 years old), the prevalence of poor concentration and passive behavior problems increased with age, while aggressive behaviors decreased. Behaviors such as thumb-sucking, nail-biting, bed-wetting and tics decreased. 2. Over the six years of this study, many behavior problems in areas of activity, mood, volition, human relations and abnormal symptoms showed significant persistence, although the degree of the persistence was not very strong. 3. Significant relationships between behavior problems observed at age three to seven years and mental health problems such as refusal to attend school and antisocial behaviors after six years were not seen.

Adolescent↗
PubMed1990

[A mortality study of middle-aged and elderly Koreans in Kawasaki City in comparison with Koreans in Korea and Japanese in Kawasaki City].

This study examined the differences in mortality rate among the three ethnic groups aged 35 to 69: 1) Japanese living in Kawasaki city, 2) Koreans living in Kawasaki city, 3) Koreans living in Korea. Three different measures were used for analysis: 1) mortality rate by sex and age, 2) Mantel-Haenszel Rate Ratio (MHRR), 3) Standardized Proportional Mortality Ratio (SPMR). Major findings were as follows: 1) In terms of mortality rate by sex and age, Koreans in both Kawasaki and Korea showed higher mortality rates than Japanese in Kawasaki for both sexes and for all of the age categories. Koreans living in Kawasaki and Koreans living in Korea showed nearly identical levels of mortality rate for both sexes and for all of the age categories. 2) Calculation of MHRR utilizing a mortality rate for Japanese living in Kawasaki as 1 yielded the following: For all causes of death, MHRR of Korean males living in Kawasaki aged 35 to 59 was 2.59, and 2.37 for ages 60 to 69. For females MHRR for those age groups were 1.91 and 2.06 respectively. All of these MHRRs were statistically significantly high (p less than 0.05). 3) Among the causes for the high MHRR for Korean males living in Kawasaki aged 35 to 59 compared in Japanese living in Kawasaki were the following: all Malignant neoplasms (ICD 9, 140-208), Malignant neoplasm of liver (155), Hypertensive disease (401-405), Ischemic heart disease (410-414), Pneumonia (480-486), Liver Cirrhosis (571). For males aged 60 to 69, causes were Tuberculosis (010-018), all Malignant neoplasms, Malignant neoplasm of liver, Ischemic heart disease, Disease of the pulmonary circulation and other forms of heart disease (415-429), Cerebrovascular disease (430-438), and Liver Cirrhosis. In the case of females, Tuberculosis, Disease of the pulmonary circulation and other forms of heart disease, Malignant neoplasm of trachea, bronchus and lung were causes for high MHRR for Koreans in Kawasaki aged 35 to 59. All Malignant neoplasms, Malignant neoplasm of liver, Malignant neoplasm of trachea, bronchus and lung, Accidental causes of death except motor vehicle accidents (E800-807, E826-848, E850-949) were causes for females aged 60 to 69. 4) The mortality rates for ages 35 to 69 for both sexes are similar for both Koreans living in Kawasaki and in Korea.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

[A case of cerebral cysticercosis: cyst growth is confirmed by CT scan during 6 years of follow-up].

A rare case of a 40-year-old woman with cerebral cysticercosis is reported. She has lived on the Island of Tokunoshima and has never travelled overseas. She was hospitalized in the hospital of Kagoshima University in 1980. A small cyst in the right temporal lobe, and a calcified area in the left parietal lobe was noticed on CT scan. When she was admitted to our hospital in December 1986, the cyst in the right temporal lobe was larger than it was 6 years before. An operation was performed for the cyst in the right temporal lobe. The cyst was pathologically confirmed as cysticercosis. Postoperatively, immunological reaction of cysticercosis was positive, but X-rays and CT scan of extremities showed no abnormal findings. Cerebral cysticercosis is a rare disease in Japan. CT scan is very useful in the diagnosis of this disease. Multiple cysts and calcified area in the parenchymal region are specific findings on CT scan.

Adult↗
PubMed1990

[A case of systemic lupus erythematosus with subarachnoid hemorrhage due to ruptured aneurysm].

A case of systemic lupus erythematosus (SLE) with subarachnoid hemorrhage due to a ruptured intracranial aneurysm is reported. A 31-year-old woman who had been treated with steroid for SLE was admitted to our department with severe headache, and nausea. CT scan showed subarachnoid hemorrhage and the left carotid angiogram revealed a small aneurysm at the supraclinoid portion of the left internal carotid artery. She had no neurological deficit. Hematological examination on admission showed disseminated intravascular coagulation (DIC), therefore, we decided to perform an intentionally delayed operation. In the meantime we treated the patient for DIC with FOY and methylprednisolone. The operation was performed after two weeks, when DIC had been eliminated completely. Postoperative hematological examination showed severe thrombocytopenia. We considered that SLE had come to the fore again, so we used Danazol in company with FOY and steroid. It seemed that Danazol was very effective for her. She was discharged about two months after admission with no problem. Cerebral apoplexy, such as cerebral infarction and cerebral hemorrhage, has often been seen in SLE, but subarachnoid hemorrhage due to a ruptured aneurysm is very rare. We could find only five reports of this phenomenon. Their prognoses were all, unfortunately, poor. It should be born in mind for therapy that a patient in SLE has a tendency to bleed. It seems that repeated hematological examinations and quick and proper management are important. We think that the aneurysmal formation in SLE is due to lupus vasculitis or the fragility of blood vessels due to a long use of Steroid.

Adult↗
PubMed1990

[Myocardial infarction complicating left ventricular free wall blowout rupture: a survival case after surgical repair].

A 58-year-old man who suffered from acute myocardial infarction complicated with left ventricular rupture and subacute pericardial tamponade was reported. On admission, echocardiography strongly suspected presence of intrapericardial fluid. And immediate pericardiocentesis proved left ventricular free wall rupture (LVFWR). Coronary angiography with the support of IABP revealed occlusion of LAD (# 8). Percutaneous transluminal coronary angioplasty was performed with partial success. After pericardiotomy, the hemodynamic state was improved, however, 2 hours later, his blood pressure fell down to 40 mmHg suddenly. Emergent operation (re-mediastinumotomy+ ) was performed under the suspicion of left ventricular blowout rupture with the direct closure of the perforated site with 4 woven Dacron pledgets at bedside in ICU. The patient ran an uneventful postoperative course and is now doing well. Clinical and therapeutic features of LVFWR were discussed.

Angioplasty, Balloon, Coronary↗
PubMed1990

[Intraoperative ABR monitoring during cerebello-pontine angle surgery].

Intraoperative auditory brainstem response (ABR) monitoring was performed in 27 patients undergoing C-P angle surgery (12: hemifacial spasm, 10: trigeminal neuralgia, 2: glossopharyngeal neuralgia, 3: C-P angle tumor, 2 epidermoid, 1 meningioma). Because of the introduction of this method, no patient suffered from postoperative hearing disturbance in this series. During C-P angle surgery, the wave V of ABR changes according to the retraction of the cerebellum and the manipulation of the eighth cranial nerve. Many authors have discussed this change, however the timing and the mechanism of disappearance of wave V is unclear. Accordingly, the authors discussed the correlation between the prolongation of wave V latency and its amplitude. The wave V amplitude was measured from the positive peak of wave V to the next negative peak. Then, the correlation between the prolongation of wave V latency and its reduction ratio (%) of amplitude was represented as a parabola. The wave V reduces its amplitude when the prolongation of the latency is from 1.5 ms to 2.0 ms. Once the prolongation of the latency is over 1.5 ms, the amplitude of wave V seems to be reduced suddenly, because it takes over 1'30'' to finish each record. But the authors demonstrated the gradual reduction of the amplitude of wave V in Figure 3. As mentioned above, the prolongation of wave V latency must be less than 1.5 ms, and the neurosurgeon must recognize this turning point during C-P angle surgery.

Cerebellopontine Angle↗
PubMed1990

[Assessment of myocardial viability by resting 201Tl SPECT image].

The aim of this study was to assess whether resting 201Tl scintigraphy is superior in detecting viable myocardium than previous conventional methods. We performed not only stress 201Tl SPECT but also resting 201Tl SPECT within one month in 65 patients with coronary artery disease. Resting 201Tl images were quantitatively compared with 4 hour late images of stress study using a polar map. In stress study, redistribution was recognized on 83% (25/30) of non-MI SEGs with perfusion defect in the stress 201Tl image, and on 39% (18/46) of infarcted SEGs. The agreement of resting 201Tl study with 4 hour late images of stress study was shown on 93% (28/30) of non-MI SEGs and on 52% (24/46) of MI SEGs. The increased uptake of 201Tl in resting study, however, was found on 13 (46%) of 28 MI SEGs showing fixed defects in stress study. In stress delayed image with fixed defect, the %Tl uptake of improved SEGs was higher than that of unchanged SEGs (59 +/- 10% vs 48 +/- 11%; p greater than 0.05). There was no viable myocardium which had %Tl uptake less than 40% at stress delayed image. In conclusion, the resting 201Tl imaging will give an important information as for the myocardial viability showing fixed defects, if more than 40% Tl uptake is observed.

Aged↗
PubMed1990

[Estimation of I-123 metaiodobenzylguanidine (MIBG) myocardial washout].

A crosstalk from I-123 to Tl-201 (Tl) window was 35 +/- 30% (mean +/- SD) and 30 +/- 10% in a myocardial phantom and the images of 6 patients respectively. However, the crosstalk from Tl to I-123 was approximately 1% in each. I-123 MIBG (MIBG) and Tl myocardial SPECT images were recorded in 3 normal volunteers (N), 10 patients with myocardial infarction (MI), and 4 with dilated cardiomyopathy (DCM). The MIBG and Tl imagings were performed on the other day to avoid the crosstalk. Myocardial washout rates (WR) of Tl and MIBG were derived from 15 min and 4 hour images. WR of Tl was approximately 36% in each group. On the other hand, WR of MIBG in DCM (52 +/- 7%) and MI (41 +/- 14%) groups were statistically higher than in N (24 +/- 7%) group. Thus WR of MIBG would be useful to detect abnormalities in adrenergic nervous system.

3-Iodobenzylguanidine↗
PubMed1990

[Trigeminal neuralgia associated with primitive trigeminal artery: report of two cases].

Two cases of trigeminal neuralgia associated with the primitive trigeminal artery are reported. From 1981, the authors have treated 131 trigeminal neuralgia patients with microvascular decompression. Among them, we encountered two rare cases of trigeminal neuralgia associated with the primitive trigeminal artery (PTA) and its variant (PTAV). Case 1 is a 74-year-old woman who was admitted to our hospital due to pain of maxilla and mandible. We diagnosed her pain as trigeminal neuralgia. Preoperative angiogram showed the primitive trigeminal artery arising from the cavernous portion of the right internal carotid artery (ICA). She underwent a microvascular decompression operation. We found that her right trigeminal nerve was compressed by the right superior cerebellar artery (SCA) and the right anterior inferior cerebellar artery (AICA). We transferred the offending arteries, and her pain disappeared. Case 2 is a 48-year-old man who was admitted to our hospital due to severe mandibular pain. We diagnosed his pain as trigeminal neuralgia, and he underwent a microvascular decompression operation. His left trigeminal nerve was found compressed by the left SCA and the AICA, and the AICA was arising from the direction of Meckel's cave. His severe pain disappeared completely after operation. Postoperative angiogram of his left ICA showed an aberrant artery arising from the cavernous portion of the ICA, to the region of the left AICA. This aberrant artery is a variant of PTA (PTAV). PTA and PTAV, the so called persistent congenital arteries, are said to accompany aneurysms and other vascular lesions, and affect hemodynamic stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Morphologic studies of sickle erythrocytes by image analysis.

An automated image analysis system was used to characterize the morphology of sickle cells under hypoxic conditions. Images observed by light microscopy were transferred to the image analysis system and were processed to binary (black and white) images, and were then analyzed by area, perimeter, and shape. A circular shape factor (CSF = 4 pi X[area]/[perimeter]2) was found to be useful for elucidating the degree of deformation, but it could not differentiate elongated sickle cells from maple leaf-shaped cells. By combining an elliptical shape factor (ESF = [short axis]/[long axis]) with CSF we could separate deoxygenated homozygous sickle red cells (SS cells) into several morphologically distinct groups, including non-sickled cells, maple leaf-shaped cells, and elongated sickle cells. Using this automated image analysis system, we studied morphologic changes of SS cells exposed to deoxygenation-oxygenation (d-o) cycles between PO2 of 0 and 100 mm Hg (one cycle = 12 minutes) at pHs of 6.9 and 7.4. We found that at both pHs the morphology of sickled cells after the first deoxygenation was predominantly maple leaf-shaped. The number of elongated sickled cells increased as the number of d-o cycles increased, indicating that SS cells changed from maple leaf morphology to classic elongated sickle shape during d-o cycles. Desickling occurred less during the oxygenation phase at pH 6.9 than at pH 7.4 and as the number of d-o cycles increased. These results suggest that during d-o cycles deoxyhemoglobin S fibers may align to form large bundles that do not depolymerize completely even at the arterial oxygen pressure.

Anemia, Sickle Cell↗
PubMed1990

[Acute myocardial infarction due to blunt chest trauma: a case report].

A 32-year-old man who suffered from acute myocardial infarction due to blunt chest trauma was admitted to our hospital. The first coronary angiography was performed on the 38th day after admission. We found aneurysmal dilatation, intimal flap and subintimal hematoma, so coronary dissection of the left anterior descending branch was suspected. When the second coronary angiography was performed 11 months later, those findings had disappeared.

Adult↗