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Biomedical subjects

A Tabuchi

Publications and source records attributed to A Tabuchi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Inducibility of BDNF gene promoter I detected by calcium-phosphate-mediated DNA transfection is confined to neuronal but not to glial cells.

Although DNA transfection with calcium-phosphate/DNA precipitates for promoter analysis of genes has been previously applied to primary cultures of neuronal cells, it remains uncertain whether the expression of the introduced genes in glial cells, which are also in primary culture, affects the transcriptional signals obtained. Using plasmid DNA containing the brain-derived neurotrophic factor (BDNF) gene promoter I or c-fos promoter, we investigated the optimum conditions for calcium-phosphate-mediated DNA transfection in primary culture of rat cortical neuronal cells. Normalizing the firefly luciferase activity of the experimental reporter gene to the Renilla luciferase activity of the internal control increased experimental reliability. Maximum expression of firefly luciferase activity in the cells stimulated by membrane depolarization required 6-12 hrs of incubation after stimulation. Differences in the ratio of the experimental reporter gene to the internal control did not affect experimental gene expression. Under our optimal conditions, the activation of the BDNF gene promoter I was detected in neuronal but not in glial cells. Calcium-phosphate-mediated DNA transfection should be widely applicable for promoter analysis of inducible genes in neurons.

Animals↗
PubMed1998

Primary brain tumors in children under age 3 years.

During the period from 1966 to 1996 the authors analyzed the clinicopathological characteristics of 46 cases of histologically verified primary brain tumors with symptomatic onset during the first 3 years of life. The patient group included 27 males and 19 females. There were 14 patients during the first year, 13 during the second year, and 19 during the third year. Supratentorial tumors (60.9%) were more common than infratentorial tumors. Histologically, neuroepithelial tumors predominated. The incidence of ependymal tumors, particularly malignant ones, and of neuronal/mixed neuronal-glial tumors was higher than in previous reports. Congenital brain tumors, those occurring within 2 months after birth, or tumors of dysplastic origin comprised 42.9% of the tumors that developed within 1 year of birth. At the onset, macrocephaly, failure to thrive, and seizures were prominent symptoms or signs in the younger patients. Focal neurological deficits and increased intracranial pressure predominated in the older patients. All but one patient underwent surgical treatment, and 17 patients received adjuvant therapy after surgery. The prognosis was mainly related to the histology of the malignancy. The outcome of medulloblastomas was poor. The quality of life of surviving patients was relatively good, 77.8% having better performance status (PS) than the Eastern Cooperative Oncology Group PS 2.

Brain Neoplasms↗
PubMed1998

[A case of ruptured descending thoracic aortic aneurysm due to Salmonella infection].

A 66-year-old male was admitted to our hospital because of pyrexia, chest pain and hemosptum. Inflammatory findings were made and salmonella enteritidis was detected by bacterial examination of sputum and stool. Enhanced chest CT examination disclosed a descending thoracic aortic aneurysm which had ruptured into the left lower lobe of the lung. Under a diagnosis of ruptured mycotic descending thoracic aortic aneurysm, an emergency operation was performed. A left posterolateral thoracotomy carried out after axillo-bilateral femoral bypass grafting. A pseudoaneurysm of the descending thoracic aorta had ruptured into the left lower lobe of the lung. After resection of the aneurysm, closure of both ends of the intact descending thoracic aorta and a left lower lobectomy were carried out. An ascending aorta-infrarenal abdominal aorta bypass was performed because of insufficient visceral arterial blood flow through the axillo-bilateral femoral bypass. The patient's immediate postoperative recovery was complicated by paraplegia. Chloramphenicol and levofloxacin were administered for three months, after which his recovery followed a good course.

Aged↗
PubMed1998

Attenuation of cell death mediated by membrane depolarization different from that by exogenous BDNF in cultured mouse cerebellar granule cells.

Membrane depolarization accompanying calcium (Ca2+) influx into neurons is thought to play an essential role in controlling the survival and death of cultured mouse cerebellar granule cells (CGCs). In this study, we sequentially controlled the survival and death of CGCs in culture and monitored the expression of several kinds of genes including brain-derived neurotrophic factor (BDNF) gene. Deprivation and subsequent induction of membrane depolarization by lowering and re-elevating the extracellular concentration of potassium chloride, respectively, led to death of CGCs and then to an attenuation of the death process depending upon the Ca2+ influx into CGCs through voltage-dependent calcium channels (VDCCs). De novo protein synthesis was critical for attenuating the death of non-depolarized CGCs. Accompanying this attenuation was an activation of c-fos and BDNF genes and an inactivation of c-jun and neurotrophin-3 (NT-3) genes. The attenuation of cell death mediated by exogenous BDNF was only partial compared to that by membrane depolarization, suggesting that not only BDNF but also other factors could be involved in the membrane depolarization-mediated attenuation of death of CGCs. In good agreement with this observation, the mode of activation of c-fos, c-jun, BDNF and NT-3 genes induced by exogenous BDNF was different from that induced by membrane depolarization. Thus, membrane depolarization effectively attenuates the death of non-depolarized CGCs, the mode of which seems to be different from that mediated by BDNF alone.

Animals↗
PubMed1998

Primary intracranial germinoma involving the midbrain.

To our knowledge, this is the first reported case of a germinoma involving the midbrain without the demonstrable coexistence of any common midline tumors. A 27-year-old man was referred to our institution for evaluation and treatment of diplopia persisting for 5 years. Magnetic resonance imaging (MRI) showed the mass in the midbrain to be of iso intensity on T1-weighted images, and of high intensity on T2-weighted images with homogeneous enhancement. MRI-guided stereotactic biopsy was performed, and the histologic diagnosis was germinoma. Following biopsy, external beam radiotherapy of 50 Gy (whole brain 30 Gy: local 20 Gy) was performed. At the time of discharge, the patient's neurological symptoms had resolved. Follow-up MRI revealed disappearance of the tumor. These findings suggest the diagnostic value of magnetic resonance image-guided stereotactic biopsy in the differential diagnosis of adult brainstem lesions, which should now include germinoma.

Adult↗
PubMed1998

Left ventricular mass regression after implantation of St. Jude Medical cardiac valves in small aortic roots.

In this study, we analyzed the extent of regression of left ventricular hypertrophy in patients who received small St. Jude Medical (SJM) aortic valves and compared the results with those of another group receiving larger valves. Eighty-eight patients received either 19 or 21 mm valves (Group 1, 25 patients) or either 23 or 25 mm valves (Group 2, 53 patients). Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up a significant reduction in the left ventricular mass was found for both patient groups (p < 0.0001). Doppler echocardiography derived pressure gradients for both groups were obtained during the follow-up period. As expected, the patients in Group 1 had higher peak pressure gradients than did those in Group 2. However, there was no significant difference between the 2 groups or any significant correlations between peak pressure gradients and body surface area (BSA). Actuarial survival was 84.7% at 15 years for Group 1 and 85.9% at 17 years for Group 2. Actuarial freedom from valve related events was 91.4% at 15 years for Group 1 and 82.7% at 17 years for Group 2. There was no significant difference in survival or valve related event free curves between the 2 groups. After implantations of SJM valves in small aortic roots, significant left ventricular mass regression was obtained, and the results were comparable to those for valves of other sizes. The long-term performance of aortic valve replacement with small valves was satisfactory as judged by improvement in the functional class of patients and survival statistics, the durability of the prosthesis, and valve related morbidity comparable to that of valves of other sizes.

Adult↗
PubMed1998

[Long-term follow-up of patients with small St. Jude aortic valve prostheses].

Thirty-five patients received small sized 19 or 21 mm valves (group I) and 53 patients received 23 or 25 mm valves (group II). At follow-up a significant reduction in the left ventricular mass was found for both patient groups (p < 0.0001). The patients in group I had higher peak pressure gradients than did those in group II. However, there was no significant difference between the two groups, or any significant correlation between peak pressure gradients and body surface area. Actuarial survival was 84.7% at 15 years for group I and 85.9% at 17 years for group II. Actuarial freedom from valve-related events was 91.4% at 15 years for group I and 82.7% at 17 years for group II. There was no significant difference in survival or valve-related event free curves between the two groups. After implantation of small SIM valves, significant left ventricular mass regression was obtained and the results were comparable to those for valves of other sizes. The long-term performance of aortic valve replacement with small valves was satisfactory as judged by improvement in the functional class of patients, survival statistics, the durability of the prosthesis, and valve related morbidity comparable to that of valves of other sizes.

Aged↗
PubMed1997

Interaction of P1 RepA with replication origin of plasmid Rts1: capability of an initiator protein inducing replication from a foreign origin.

Rts1 RepA and P1 RepA are trans-acting proteins essential for the initiation of replication of plasmid Rts1 and prophage P1, respectively. In this study, we found that, in vitro, P1 RepA bound to the Rts1 ori fragment and Rts1 incI fragment as strongly as Rts1 RepA. In addition P1 RepA, in trans, activated the Rts1 replication origin that was cloned in pBR322, thus allowing the ori plasmid to be maintained in a polA E. coli host. Under these conditions, however, the ori plasmid was unstable as compared with that when activated by Rts1 RepA. In addition, we found that Rts1 RepA showed no interaction with the P1 replication origin.

Bacteriophage P1↗
PubMed1997

Synthesis of glycosyl-trehaloses by cyclomaltodextrin glucanotransferase through the transglycosylation reaction.

Cyclomaltodextrin glucanotransferase from Bacillus stearothermophilus produced a series of glycosyl-trehaloses through the transglycosylation reaction with cyclomaltohexaose as the glycosyl donor and trehalose as its acceptor. After beta-amylase treatment, five species of glycosyl-trehaloses were isolated by column chromatography. After chemical and enzymatic analyses, it was concluded that these oligosaccharides were alpha-maltosyl alpha-D-glucopyranoside, alpha-maltotriosyl alpha-D-glucopyranoside, alpha-maltosyl alpha-maltoside, alpha-maltotriosyl alpha-maltoside, and alpha-maltotriosyl alpha-maltotrioside. These were not hydrolyzed by salivary amylase, artificial gastric juice, or pancreatic amylase, however they were hydrolyzed by enzymes of the small intestine.

Carbohydrate Sequence↗
PubMed1997

[A case report of malignant schwannoma of the chest wall].

We described a very rare case of malignant schwannoma of the chest wall, which was surgically resected. The patient, a 40-year-old woman, came to our hospital because of an abnormal shadow in the right chest wall of an X-ray film without any symptoms. Computed tomography revealed a solid tumor attached to the posteroinferior aspect of the intrathoracic chest wall. The tumor was a 2.5 x 2.1 cm, mass originating from the seventh intercostal nerve without pulmonary adhesion, and the patient underwent en bloc resection of the tumor. The pathological diagnosis was malignant schwannoma. The postoperative course was uneventful, and the patient, eight years after the operation is now doing well without local recurrence or distant metastasis. We reviewed seven cases of this type of tumor reported in the Japanese literature.

Adult↗
PubMed1997

[Recurrent intrathoracic dissemination of thymoma with myasthenia gravis: a case report].

A 48-year-old man was readmitted to our hospital with a chief complaint of left anterior chest mass. He had a past history of thymo-thymomectomy six years earlier. On chest CT examination, multiple tumor shadows were noted within the left thoracic cavity. All visible tumors were resected. His postoperative course was favorable, and no signs of recurrence have been recognized on CT to date (three years and six months postoperatively). However, in view of the possible recurrence of the present disease after a long period, strict observation of the course of the disease is necessary.

Humans↗
PubMed1997

[Ruptured descending thoracic aortic aneurysm due to aortitis syndrome--a case report].

Ruptured fusiform descending thoracic aortic aneurysms due to aortitis syndrome are rare. A 29-year-old woman was readmitted to our hospital with a chief complaint of back pain and shock, and diagnosed as having rupture of a descending thoracic aortic aneurysm. She had a past history of aortitis syndrome beginning eight years ago. On chest CT examination earlier a year, the descending thoracic aortic aneurysm was 4.5 cm in diameter, and calcification we observed in the aortic wall. An inflammatory reaction had been controlled by steroid therapy and her blood pressure had been controlled by vasodilator drugs. Emergent graft replacement of a descending aortic aneurysm was successfully performed under a femoro-femoral bypass using a centrifugal pump and membrane oxygenerator, and Cell Sver. Although in the literature surgical treatment is indicated only if there is a symptomatic or enlarging aneurysm especially of saccular type and no operation is justified for an aortic aneurysm showing marked calcification, we concluded that aggressive surgical treatment was necessary for this fusiform aneurysm due to aortitis syndrome.

Adult↗
PubMed1997

[Visual acuity measured by pattern visual evoked potential].

We investigated the appropriateness of a method for the assessment of visual acuity using pattern visual evoked potentials (PVEP) in which retinal X-ganglion cells are predominantly stimulated. Eighteen normal eyes (average 22.2 years old) with normal acuity of 1.0 were examined. The stimulus consisted of white and black checkerboards (39', 26', 15' and 9') with a visual angle of eight degrees and a contrast level of 15%. The pattern reversal frequency was 0.7 Hz. This resulted in 100 averaged PVEP per session. We judged visual acuity from responses of the P100 component. Visual acuity was judged to be 0.1, so that there was response to the 39' checkerboard stimulus pattern, but not to the 26' pattern. Consequently, the accuracy for visual acuity was 76.9% for 0.1, 71.4% for 0.2, 70.0% for 0.5 and 58.3% for 1.0. This method, which uses a stimulus pattern with a small visual angle, low contrast, and low pattern reversal frequency, is useful for subjective measurement of the visual acuity of infants or handicapped children whom it is difficult to measure by the conventional objective method of measuring visual acuity with Landolt's rings.

Adult↗
PubMed1997

The diagnosis and management of splanchnic artery aneurysms. Report of 8 cases.

The purpose of this report is to describe the clinical characteristics and surgical technique for splanchnic artery aneurysms. Over the past 10 years we have surgically resected 8 cases of splanchnic artery aneurysms including 2 cases involving the superior mesenteric artery, 3 involving the renal artery, 1 involving the hepatic artery and 2 involving the splenic artery. Diagnosis was established preoperatively in all patients by splanchnic angiography. Surgical treatment for splanchnic artery aneurysms is indicated in any symptomatic patient, in all symptomatic patients with suspected renal aneurysmal expansion and in patients who have renal aneurysms occurring with functionally important renal stenosis, usually associated with hypertension, in all patients with surgical accessible hepatic artery aneurysms, in all patients who have superior mesenteric artery aneurysms having a high tendency to rupture, and in all patients with an asymptomatic splenic artery aneurysms 1.5 cm or larger in diameter. Although splanchnic artery aneurysms are uncommon and asymptomatic, we recommend that splanchnic arteries should be treated surgically because of their tendency to rupture or organ failure.

Adult↗
PubMed1997

[Brain damage after surgery for thoracic aortic aneurysm].

We analyzed cases with brain damage after surgery for thoracic aortic aneurysm in our institution and investigated the causes, risk-factors and preventive measures for this disastrous postoperative complication. Irreversible brain damage was a complication in 25 out of 184 operative cases (13.6%) over a 21-year period. The cause of brain damage was determined to be embolism by manipulation of the aorta in six cases, clamping of the left subclavian artery in four cases, technical problems of separate cerebral perfusion (SCP) in four cases, severe shock in three cases, embolism unrelated to operative maneuver in three cases, stenosis of a branch of the arch with aortic dissection in two cases, and air embolism, circulatory arrest with insufficient hypothermia and hypoperfusion of a temporary bypass to the left carotid artery in one case each. The neurological symptom improved in eight cases and was unchanged in 17 cases. Eighteen cases died in the hospital. In the univariate analysis, age (p = 0.048), a portion of the aneurysm (p = 0.035), preoperative brain complication (p = 0.003), emergency operation (p = 0.033) and clamping of the arch (p = 0.001) were found to be prominent risk factors for brain damage. In the multivariate analysis, clamping of the arch (p = 0.0310), SCP (p = 0.0327) and emergency operation (p = 0.0223) were prominent. To prevent postoperative brain damage, the arch should not be clamped, appropriate operative techniques to avoid bleeding and to shorten SCP time should be employed, and proper and prompt management of the emergency operation and caution in clamping the left subclavian artery are considered to be necessary.

Adult↗
PubMed1996

BDNF gene can Be activated by Ca2+ signals without involvement of de novo AP-1 synthesis.

Although stimulation of N-methyl-D-aspartate receptors or voltage-dependent calcium channels induces both the activation of c-fos and brain-derived neurotrophic factor (BDNF) genes, it is not certain how the activation of these genes is related. Using primary cultures of rat hippocampal neurons, we found that exposing the cells to cycloheximide allowed subsequent activation of BDNF mRNA expression, although activation of AP-1 DNA-binding activity resulting from the c-fos induction was abolished. Super-induction of BDNF gene was also caused by cycloheximide. The estimated half-life of BDNF mRNA was approximately 2.5 hrs, which was almost identical to that of c-fos mRNA. These results indicate that nascent AP-1 is not required for the activation of BDNF gene, leading to the notion that the BDNF gene can be activated by Ca2+ signals as an immediate early gene.

Animals↗