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Biomedical subjects

T Aoki

Publications and source records attributed to T Aoki.

At least 343 records · Page 19Linked to original sources
PubMed1998

Identification of a cytochrome P450 cDNA encoding (2S)-flavanone 2-hydroxylase of licorice (Glycyrrhiza echinata L.; Fabaceae) which represents licodione synthase and flavone synthase II.

The microsome of insect cells expressing CYP Ge-5 (CYP93B1), a cytochrome P450 cDNA of licorice (Glycyrrhiza echinata L.), catalyzed the formation of [14C]licodione and [14C]2-hydroxynaringenin from (2S)-[14C]liquiritigenin and (2S)-[14C]naringenin, respectively. On acid treatment, the products were converted to 14C-labeled 7,4'-dihydroxyflavone and apigenin. Eriodictyol was also converted to luteolin by the reaction with the microsome of yeast expressing CYP93B1 and subsequent acid treatment. CYP93B1 was thus shown to encode (2S)-flavanone 2-hydroxylase, which has previously been designated to licodione synthase and flavone synthase II depending on the substrates employed.

Animals↗
PubMed1998

Beam commissioning of the SPring-8 synchrotron.

The beam commissioning of the SPring-8 synchrotron was started in December 1996. In the first ten days, the coarse tuning of the pulse magnets for beam injection from the linac, and the excitation pattern of the dipole and the quadrupole magnets, were accomplished during energy ramping of the beam. The acceleration of the beam up to 8 GeV proceeded smoothly. From January to February 1997, the fine-tuning of the synchrotron was continued and the operating parameters of all of the synchrotron equipment were decided.

Journal Article↗
PubMed1998

Response of intra-acinar pulmonary microvessels to hypoxia, hypercapnic acidosis, and isocapnic acidosis.

To elucidate the differential reactivity of pulmonary microvessels in the acini to hypoxia, excessive CO2, and increased H+, we investigated changes in the diameter of precapillary arterioles, postcapillary venules, and capillaries in isolated rat lungs on exposure to normocapnic hypoxia (2% O2), normoxic hypercapnia (15% CO2), and isocapnic acidosis (0.01 mol/L HCl). Microvascular diameters were precisely examined using a real-time confocal laser scanning luminescence microscope coupled to a high-sensitivity camera with an image intensifier. Measurements were made under conditions with and without indomethacin or N(omega)-nitro-L-arginine methyl ester to assess the importance of vasoactive substances produced by cyclooxygenase (COX) or NO synthase (NOS) as it relates to the reactivity of pulmonary microvessels to physiological stimuli. We found that acute hypoxia contracted precapillary arterioles that had diameters of 20 to 30 microm but did not constrict postcapillary venules of similar size. COX- and NOS-related vasoactive substances did not modulate hypoxia-elicited arteriolar constriction. Hypercapnia induced a distinct venular dilatation closely associated with vasodilators produced by COX but not by NOS. Arterioles were appreciably constricted in isocapnic acidosis when NOS, but not COX, was suppressed, whereas venules showed no constrictive response even when both enzymes were inhibited. Capillaries were neither constricted nor dilated under any experimental conditions. These findings suggest that reactivity to hypoxia, CO2, and H+ is not qualitatively similar among intra-acinar microvessels, in which COX- and NOS-associated vasoactive substances function differently.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Focal, high dose, and fractionated modified stereotactic radiation therapy for lung carcinoma patients: a preliminary experience.

BACKGROUND: Stereotactic radiation therapy is highly effective in the treatment of small brain metastases, regardless of the histology. This suggests that small extracranial malignancies may be curable with similar radiation therapy. The authors developed a novel treatment unit for administering such therapy. METHODS: The unit consisted of a linear accelerator (linac), an X-ray simulator (X-S), computed tomography (CT), and a table. The gantry axes of the three machines were coaxial and could be matched by rotating the table. Patients were instructed to perform shallow respiration with oxygen. The motion of the tumor was monitored with the X-S. When the motion was slight enough, the table was rotated to the CT. To include all geometric movement on the CT images, each scan was made while the patient was performing shallow respiration. After the CT positioning, the table was rotated to the linac, and non-coplanar treatment was given. Beginning in October 1994, 45 patients with 23 primary or 43 metastatic lung carcinomas were treated. Radiation doses at the 80% isodose line were 30-75 gray in 5-15 fractions over 1-3 weeks with or without conventional radiation therapy. RESULTS: The treatment was performed with no or minimal adverse acute symptoms. The daily treatment time was short. During a median follow-up of 11 months, local progression occurred in 2 of 66 lesions. Interstitial changes in the lung were limited. CONCLUSIONS: With this unit and procedure, focal radiation therapy similar to stereotactic radiation therapy is possible for extracranial sites. The preliminary experience appeared safe and promising, and further exploration of this approach is warranted.

Adenocarcinoma↗
PubMed1998

Identification of a distinct antibacterial domain within the N-lobe of ovotransferrin.

We have evaluated the bactericidal activity of hen ovotransferrin (OTf), which was found to operate regardless of its iron-deprivation properties, with the objective of isolating the bactericidal domain. The amino-terminal half-molecule (N-lobe, residues 1-332) of OTf, isolated by trypsin-nicking, retained the bactericidal activity independently of iron-deprivation, but not the carboxyl-terminal half-molecule (C-lobe, residue 342-686), suggesting the presence of a bactericidal domain within the N-lobe of the molecule. Specific cleavage at the aspartyl residues of OTf, by diluted-acid procedure, yielded fairly large peptides, whereas proteolysis for 150 min produced the strongest bactericidal peptides mixture. The bactericidal domain was purified from the active hydrolysate by gel filtration and reversed-phase HPLC and showed activity against S. aureus as well as E. coli K-12. Electrophoretic analysis on tricine-SDS-PAGE revealed a bactericidal peptide with an average M(r) of 9900 Da under non-reducing conditions. In combination with the specificity of cleavage (Asp-X) and the molecular mass, its N-terminal microsequencing corresponded to a cationic peptide consisting of 92 residues located within the 109-200 sequence of the N-lobe of OTf, containing three intrachain disulfide bridges, featuring a common structural motif occurs in the N-lobes of transferrins for which the sequence is available. Two of the disulfides (C160-C174 and C171-C182) form surface exposed cringle bridges lying on the opposite side of the iron-binding site from the interdomain cleft and showing marked sequence homology to insect defensins, which are blockers of the voltage-dependent K+ channels. The peptide lost antibacterial activity when its disulfide bonds were reduced, indicating the importance of its tertiary structure for the exertion of antibiotic activity.

Amino Acid Sequence↗
PubMed1998

Rapid diagnosis of red sea bream iridovirus infection using the polymerase chain reaction.

A simple and sensitive polymerase chain reaction (PCR) based assay is described for detection of the red sea bream iridovirus (RSIV) in infected fish. The assay involves amplification of a portion of the ribonucleotide reductase small subunit (RNRS) gene of the virus from DNA isolated from the spleen. The system was tested on red sea bream following an experimental infection. In our infection model, disease signs first became apparent 5 to 6 d post-infection, and mortality commenced at Day 6 and reached 90% by Day 9. No amplified product was detected from fish at 1 or 2 d post-infection, but 3 of 5 fish tested positive at Day 3, and all fish tested positive at Days 5 and 8. Thus, infection could be detected prior to the appearance of overt symptoms. This PCR method should be of considerable value for aquaculture to detect RSIV infection.

Animals↗
PubMed1998

Comparison of the antithrombotic effects of FK633, GPIIb/IIIa antagonist, and aspirin in a guinea pig thrombosis model.

Antiplatelet and antithrombotic effects of FK633 (a GPIIb/IIIa antagonist) and aspirin were compared. FK633 at 0.32 mg/kg i.v. or aspirin at 10 mg/ kg i.v. inhibited ex vivo collagen-induced aggregation by >50% for 1 hour in guinea pigs. However, aspirin was very weak in inhibiting ADP-induced aggregation. In vivo antithrombotic effects of FK633 and aspirin were compared using a FeCl3-induced carotid artery thrombosis model in guinea pigs. Pretreatment with 0.32 mg/kg i.v. of FK633 significantly prevented occlusive thrombus formation, but aspirin at 10 mg/kg i.v. did not. In thrombolysis experiments, adjunctive use of FK633 (0.32 mg/kg i.v.) with rt-PA (0.3 mg/kg bolus+1.0 mg/kg/hr) achieved reperfusion in five of five animals without reocclusion. Aspirin (10O mg/kg i.v.) with rt-PA also achieved reperfusion in three of five animals with high incidence of reocclusion. These results suggest that FK633 may be a more effective antithrombotic agent than aspirin due to its agonist-independent antiplatelet effects.

Animals↗
PubMed1998

Non-familial olivopontocerebellar atrophy combined with late onset Alzheimer's disease: a clinico-pathological case report.

A 76-year-old woman with olivopontocerebellar atrophy (OPCA) presented with progressive intellectual deterioration. She showed cerebellar ataxia and muscle atrophy and weakness, and gradually developed generalized dementia with visuospatial disturbance. An autopsy revealed numerous senile plaques (SPs), neurofibrillary tangles (NFTs) and neuropil threads particularly in the CA1, subiculum and entorhinal cortex and to a lesser degree in the cerebral neocortex shown by immunostaining and specific silver impregnation techniques. The nucleus basalis of Meynert had numerous NFTs with fibrillary gliosis and neuronal cell loss. The basis pontis was markedly atrophied and the pontine nucleus had severe neuronal depopulation and gliosis. The pontine transverse fibers were demyelinated with their axons being fragmented. The cerebellar white matter was also severely degenerated. The striatum, Onuf's and intermediolateral nuclei of the spinal cord remained unchanged. Ubiquitin immunohistochemistry and Gallyas silver impregnation technique revealed oligodendroglial inclusions in the pontine nucleus, corticopontine tract, cerebral and cerebellar white matter. On double immunostaining of KP1 and ubiquitin, globular neurite SPs encircled by KP1-positive fibrous structures were found in the hippocampus and cerebral neocortex. The curly neurite SPs contained KP1-positive granules. The KP1-positive microglial cells were distributed widely in the cerebral white matter and HLA-DR-positive ones were found around the SPs. The present case showed generalized dementia compatible with Alzheimer's disease (AD) and had a pathologically limbic type of late onset AD. This is the first case where AD affected non-familial OPCA.

Aged↗
PubMed1998

Treating bullous lung disease with Holmium YAG laser in conjunction with fibrin glue and DEXON mesh.

BACKGROUND AND OBJECTIVE: Holmium YAG (Ho:YAG) laser energy is highly absorbed by water, and this property is useful to uniformly ablate pulmonary bullae. The current study summarizes the data of a 39-month follow-up of patients treated for bullae with a Ho:YAG laser. STUDY DESIGN/MATERIALS AND METHODS: We used a Ho:YAG laser from August 1994 to April 1997 to treat small pulmonary bullae in 50 patients. For the first five patients, Ho:YAG laser ablation was followed by resection for histological assessment. In the next six patients, fibrin glue was applied following bullae ablation with the Ho:YAG laser. In all subsequent patients, a DEXON, (polyglycolic acid) mesh patch soaked in fibrin glue was employed after ablation. RESULTS: From the six patients receiving only the fibrin glue following laser ablation, delayed pneumothorax developed in one patient. In the subsequent 39 patients patched with DEXON mesh soaked in fibrin glue, none encountered delayed pneumothorax. CONCLUSION: The combined use of fibrin glue and Dexon mesh with the Ho:YAG laser may be an effective technique for treating bullous lung disease.

Aluminum Silicates↗
PubMed1998

Endometrial cytology in postmenopausal hormone replacement therapy.

Endometrial changes is postmenopausal hormone replacement therapy (HRT) were studied by comparing cytological and histological findings. Cytological and histological examinations were conducted on 138 benign cases and 26 abnormal cases, including 24 cases with disordered proliferative phase (DOP) and 2 cases with simple endometrial hyperplasia (SEH), for a total of 164 cases. Hormones were administered as follows: 1) single cyclic administration of estrogen only (Single-HRT) for 31 cases, 2) cyclic administration of estrogen and progestin (Cyclic-HRT) for 105 cases, and 3) continuous administration of estrogen and progestin (Continuous-HRT) for 28 cases. All of the 164 cases were studied cytologically as to shape, appearance, nuclear number on maximum diameter, and so on. The benign cases in each mode of administration as described above revealed the following: 1) Single-HRT, atrophy or the proliferative phase was noted histologically, and the copresence of the endometrial epithelium and the ciliated cell metaplasia was observed cytologically; 2) Cyclic-HRT, the first half of the administration term was of the proliferative phase histologically, and the linear and long glands were seen cytologically. In the latter half of the administration term the secretory phase was noted histologically and the curved/linear glands with subnuclear vacuolization were observed cytologically; and 3) Continuous-HRT, atrophy was noted histologically, and fewer glands and atrophic cells on the endometrial epithelium with wrinkles mixed therein were seen cytologically. On the other hand, cytological examinations of the abnormal cases revealed a mean average of 35 nuclei on the maximum diameter of the gland, protrusion and/or ramification of the glands, densely clustered glands, and back-to-back glands without fusion, as well as irregularly dilated tortuous glands in SEH. These abnormal findings were considered useful for early detection of endometrial disorders in the hormone replacement therapy by cytodiagnosis.

Adult↗
PubMed1998

Development of primary leiomyosarcoma of the sternum postirradiation: report of a case.

We report herein the case of a 30-year-old man who developed a primary leiomyosarcoma (LMS) 11 years after undergoing a median sternotomy for mediastinal seminoma followed by 50 Gy radiotherapy. He was given two courses of chemotherapy, resulting in 90% tumor regression, after which resection of the tumor with adjacent chest wall structures was carried out. Reconstruction was performed using a methylmethacrylate prosthesis prepared preoperatively. Postoperatively, he received two additional courses of chemotherapy and has had no sign of recurrence for 45 months.

Adult↗
PubMed1998

A comparison of biopsy through a parasternal anterior mediastinotomy under local anesthesia and percutaneous needle biopsy for malignant anterior mediastinal tumors.

The various methods of treating the numerous types of anterior mediastinal neoplasms are undergoing refinements; however, prior to the commencement of any treatment, an accurate histologic diagnosis must be established. We conducted a retrospective analysis of biopsies performed through a parasternal anterior mediastinotomy (PAM) on 21 patients with an anterior mediastial mass suspected of being malignant by computed tomography (CT) and other clinical information. Patients with possible localized thymomas were excluded. Mediastinotomy, which enables relatively large tissue samples to be taken, was performed through the bed of the second or third costal cartilage under local anesthesia. In 19 of the 21 patients (90%), the histologic diagnosis made from the mediastinotomy biopsy was identical to the final diagnosis. Conversely, although the tissue obtained from needle biopsy was sufficient for a histologic diagnosis in 11 of 12 patients, the histologic diagnosis made from the needle biopsy was the same as the final diagnosis in only 5 of 10 patients (50%). Thus, diagnostic accuracy was significantly higher in the mediastinotomy biopsies than in the needle biopsies (P = 0.0318). Moreover, the mediastinotomy biopsy specimens revealed subtypes of lymphomas and germ cell tumors. All of the patients from whom a mediastinotomy biopsy had been taken began appropriate therapy without delay according to the histologic diagnosis. These results suggest that the PAM approach should be chosen as the preferred method of biopsy for suspected malignant anterior mediastinal tumors.

Adolescent↗
PubMed1998

Clinical evaluation of irreversible data compression for computed radiography of the hand.

We evaluated the clinical utility of high data compression for computed radiography (CR) of the hand. Paired original and compressed CR images were obtained using an FCR 9000 system in 35 patients with various abnormalities of the hand. For the paired original and compressed images, we compared the depiction of the bone cortex, bone trabeculae, soft-tissue, and the margin of the abnormalities. The overall impressions for detectability of the abnormalities and for diagnostic capability were also evaluated. Poorer image quality of the compressed images was noted for most of the structures, but there was no significant difference between the original and compressed images as for the overall impressions for detectability of the abnormalities or for diagnostic capability. We conclude that a high data compression may be clinically acceptable with caution in radiography of the hand.

Female↗
PubMed1998

Effect of pirenzepine on gastric endocrine cell kinetics during lansoprazole administration.

We studied the effect of pirenzepine on gastric secretion kinetics in rats in a hypochlorhydric state induced by lansoprazole, a proton pump inhibitor. Pirenzepine was administered intramuscularly at a dosage of 20 mg/kg twice daily; and lansorprazole, subcutaneously at 50 mg/kg once daily, both every day for 4 weeks. After the 4-week treatment, serum gastrin and plasma somatostatin levels were determined by radioimmunoassay. In addition, gastrin cells, somatostatin cells, and enterochromaffin-like cells were immunostained and counted. Serum gastrin levels were elevated, and gastrin and enterochromaffin-like cell numbers increased in the group on lansoprazole alone, compared with these values in the control group (which received distilled water). In the group on the lansoprazole and pirenzepine combination, serum gastrin levels decreased, and gastrin and enterochromaffin-like cell numbers were significantly decreased, compared with the respective variables in the group on lansoprazole alone, while the number of somatostatin cells increased in the group on the combination. Plasma somatostatin levels did not vary significantly in any group. It was thus demonstrated that pirenzepine corrects the abnormal gastric secretion kinetics resulting from treatment with lansoprazole alone, such as hypergastrinemia and gastrin and enterochromaffin-like cell hyperplasia.

2-Pyridinylmethylsulfinylbenzimidazoles↗