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Biomedical subjects

S Tamura

Publications and source records attributed to S Tamura.

At least 127 records · Page 7Linked to original sources
PubMed2000

Image-guided microsurgery with the Mehrkoordinaten Manipulator system for cerebral arteriovenous malformations.

Four patients with cerebral arteriovenous malformations (AVMs) underwent image-guided microsurgery with the Mehrkoordinaten Manipulator (MKM) system, which integrates a robotic microscope with a computer workstation. The patients were all male, from 8 to 51 years old (mean = 24), all presenting with intracerebral haemorrhage. The lesion was located in the deep sylvian fissure in one patient, the fronto-parieto-occipital area in one and the trigone in two. Stereotactic computed tomography and magnetic resource imaging of 1-mm slices were taken. The extent of AVM and the draining vein, predetermined with the MKM workstation, could be superimposed on the microscopic view, resulting in minimum scalp incision and craniotomy, as well as allowing for a stereotactic approach to deep-seated lesions. Superimposition of the contour of the lesion was also useful for resecting the lesion, although intraoperative diagnosis of the total resection required intraoperative digital subtraction angiography. In conclusion, image-guided microsurgery with the MKM system can assist minimally invasive and maximally effective microsurgery for cerebral AVMs.

Adolescent↗
PubMed2000

Vitamin E supplementation attenuates leakage of enzymes following 6 successive days of running training.

The purpose of this study was to examine whether vitamin E supplementation in humans would attenuate an increase of serum enzymes as an indirect marker of muscle damage following a sudden large increase in the running distance in a 6-day running training or not. A randomized and placebo-controlled study was carried out on fourteen male runners who were supplied vitamin E (alpha-tocopherol 1200 IU x day(-1); E) or placebo (P) 4 weeks prior to (T1) and during 6 successive days of running training (48.3 +/- 5.7 km x day(-1), means +/- SD). Resting venous blood samples were obtained before maximal treadmill running, at T1, the day immediately before (T2), the next day (T3), and three weeks (T4) after the running training. Serum levels of alpha-tocopherol, lipid peroxidation products (thiobarbituric acid; TBA), creatine kinase (CK), lactate dehydrogenase (LDH), and LDH isozyme 1-5 were quantitatively analyzed. No significant difference was found in maximal oxygen uptake (VO2max) and maximal heart rates following the exhaustive exercise between the P and E group during the experiments. Vitamin E supplementation significantly increased serum alpha-tocopherol (p<0.001) and decreased TBA levels (p < 0.001) compared with pre-supplementation levels. Although serum CK and LDH activities increased significantly at T3 in either group, significantly lower CK (p < 0.05) and LDH (p < 0.001) levels were observed in the E group compared with the P group. The ratio of LDH1 to LDH2 (LDH1/LDH2) decreased significantly at T3 in either group compared with the T1 levels, since there was no significant difference in the LDH1/LDH2 between the P and E group throughout the experiments. These results indicate that vitamin E supplementation can reduce the leakage of CK and LDH following 6 successive days of endurance running. The protective effect of vitamin E against free radicals probably inhibits free-radical-induced muscle damage caused by a sudden large increase in the running distance.

Adult↗
PubMed2000

Successful endoscopic resection of intramural metastasis after esophagectomy for esophageal cancer: a case report.

Carcinoma of the esophagus is often accompanied by intramural metastasis (IM) at the time of diagnosis, and the prognosis of patients with such metastasis is very poor. Here we report the case of a 60-year-old man who presented with a submucosal tumor in the wall of the cervical esophagus at 2 years after esophagectomy for thoracic esophageal cancer. The tumor was resected endoscopically and was histologically shown to be an IM of esophageal cancer. He has shown no recurrence and no metastasis during 2 years of follow-up after endoscopic resection and radiation therapy.

Carcinoma, Squamous Cell↗
PubMed2000

Extracorporeal membrane oxygenation for the management of respiratory failure due to ANCA-associated vasculitis.

We present here two patients whose near fatal respiratory distress was caused by pulmonary hemorrhage, and who were treated successfully by extracorporeal membrane oxygenation (ECMO). The underlying disease was anti-neutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis. They were initially treated with methylprednisolone pulse therapy along with cyclophosphamide. However, their respiratory failure progressed with a low PaO2/FiO2 ratio (< 100 mmHg) despite mechanical ventilation, and ECMO was initiated. After several days, the pulmonary hemorrhage subsided, and the patients were weaned successfully from ECMO. We suggest that ECMO may be used to manage life-threatening pulmonary hemorrhage in patients suffering from ANCA-associated systemic vasculitis.

Adult↗
PubMed2000

The peroxin pex3p initiates membrane assembly in peroxisome biogenesis.

Rat cDNA encoding a 372-amino-acid peroxin was isolated, primarily by functional complementation screening, using a peroxisome-deficient Chinese hamster ovary cell mutant, ZPG208, of complementation group 17. The deduced primary sequence showed approximately 25% amino acid identity with the yeast Pex3p, thereby we termed this cDNA rat PEX3 (RnPEX3). Human and Chinese hamster Pex3p showed 96 and 94% identity to rat Pex3p and had 373 amino acids. Pex3p was characterized as an integral membrane protein of peroxisomes, exposing its N- and C-terminal parts to the cytosol. A homozygous, inactivating missense mutation, G to A at position413, in a codon (GGA) for Gly(138) and resulting in a codon (GAA) for Glu was the genetic cause of peroxisome deficiency of complementation group 17 ZPG208. The peroxisome-restoring activity apparently required the full length of Pex3p, whereas its N-terminal part from residues 1 to 40 was sufficient to target a fusion protein to peroxisomes. We also demonstrated that Pex3p binds the farnesylated peroxisomal membrane protein Pex19p. Moreover, upon expression of PEX3 in ZPG208, peroxisomal membrane vesicles were assembled before the import of soluble proteins such as PTS2-tagged green fluorescent protein. Thus, Pex3p assembles membrane vesicles before the matrix proteins are translocated.

ATP-Binding Cassette Transporters↗
PubMed2000

A new radiopharmaceutical for the cerebral dopaminergic presynaptic function: 6-radioiodinated L-meta-tyrosine.

Geometric isomers of radioiodinated L-meta-tyrosine, 6-[I-125]iodo-and 4-[1-125]iodo-L-meta-tyrosine (6-I-L-mTyr, 4-I-L-mTyr) were separated by high-performance liquid chromatography . Both 6-I- and 4-I-L-mTyr had high energy-dependent brain accumulation. 6-I- and 4-I-L-mTyr were also metabolically stable and were rapidly excreted through the urine. 6-I-L-mTyr had a predilection for the cerebral aromatic L-amino acid decarboxylase (DOPA decarboxylase), the final enzyme of dopamine biosynthesis. 6-Radioiodinated L-mTyr is a new radiopharmaceutical that can be both useful in assessing cerebral amino acid transport mechanism and quantifying metabolically active DOPA decarboxylase.

Animals↗
PubMed2000

Telemedicine for evaluation of brain function by a metacomputer.

A method of evaluating brain function using the metacomputer concept of the Globus system combined with a message-passing interface is described. The proposed method has the ability to exploit various geographically distributed resources and parallel computing linked to a high-technology medical instrumentation system, magnetoencephalography, to analyze the functional state of the brain. It is envisaged that the method will lead to the realization of an efficient telemedicine system for health care.

Brain↗
PubMed2000

A three-dimensional model of the human pulmonary acinus.

A three-dimensional (3-D) model of the human pulmonary acinus, a gas exchange unit, is constructed with a labyrinthine algorithm generating branching ducts that fill a given space completely. Branching down to the third respiratory bronchioles is generated with the proposed algorithm. A subacinus, a region supplied by the last respiratory bronchiole, is approximated to be a set of cubic cells with a side dimension of 0.5 mm. The labyrinthine algorithm is used to determine a pathway through all cells only once, except at branching points with the smallest path lengths. In choosing each step of a pathway, random variables are used. Resulting labyrinths have equal mean path lengths and equal surface areas of inner walls. An alveolus can be generated by attaching alveolar septa, 0.25 mm long and 0.1 mm wide, to the inner walls. Total alveolar surface area and numbers of alveolar ducts, alveolar sacs, and alveoli in our 3-D acinar model are in good accordance with those reported in the literature.

Algorithms↗
PubMed2000

Suppression of specific IgE antibody responses by liposome-conjugated ovalbumin in mice sensitized with ovalbumin via the respiratory tract.

BACKGROUND: Previously we have shown that intranasal administration of ovalbumin (OVA) together with cholera toxin (CT) abrogates nasal tolerance to OVA, resulting in the induction of specific IgE antibody (Ab) responses, and that intraperitoneal injection of OVA coupled with liposomes (OVA-liposomes) induces a selective suppression of IgE Ab responses to OVA. Whether OVA-liposomes suppress anti-OVA IgE Ab responses in mice sensitized with CT-combined OVA via the respiratory tract remains to be clarified. METHODS: In some experiments, mice were given OVA, liposomes or OVA-liposomes with or without CT intranasally three times, at 2-week intervals (weeks 0, 2 and 4). In other experiments, mice were given OVA-liposomes intranasally 2 days before or 1 and 3 weeks after CT-combined OVA (week 0), which was administered intranasally three times, at 2-week intervals (weeks 0, 2 and 4). Two weeks after the third administration of CT-combined OVA (week 0), nasal wash and serum IgA, IgG and IgE Ab responses were assayed. RESULTS: Pretreatment with OVA-liposomes suppressed IgE Ab responses to CT-combined OVA, with a significantly high production of both nasal IgA and serum IgG Abs. Moreover, treatment with OVA-liposomes 1 and 3 weeks after CT-combined OVA administration also suppressed IgE Ab responses. The suppression of anti-OVA IgE Ab production by OVA-liposomes was accompanied by a simultaneous enhancement of specific IgA and IgG (IgG1, and especially IgG2a) Ab production. CONCLUSIONS: Postimmunization treatment with OVA-liposomes, as well as preimmunization treatment, suppressed specific IgE Ab responses in mice sensitized intranasally with CT-combined OVA. Allergens conjugated to liposomes may be appropriate for preventing the development of allergies to inhaled or dietary antigens in humans.

Administration, Intranasal↗
PubMed2000

New imaging findings in a patient with central nervous system dysfunction after bone marrow transplantation.

Central nervous system disorders are an important complication of bone marrow transplantation (BMT). We have recently performed cerebral angiography to examine central nervous system dysfunction in a 22-year-old woman with acute lymphoblastic leukaemia who had undergone BMT. Angiography demonstrated multiple stenoses and occlusions in the peripheral branches of the anterior and middle cerebral arteries, a pattern similar to that seen in vasculitis. She was thought to most likely have cytomegalovirus (CMV) vasculitis, but other forms of vasculitis, such as angiitis-like-syndrome-associated graft-versus-host disease could not be excluded. This case suggests that CMV vasculitis may cause central nervous system dysfunction after BMT and that imaging studies may provide useful information about central nervous system disorders in these patients.

Adult↗
PubMed2000

Peroxisome biogenesis and molecular defects in peroxisome assembly disorders.

Peroxisome assembly in mammals requires more than 14 genes. So far, we have isolated seven complementation groups (CGs) of peroxisome biogenesis-defective Chinese hamster ovary (CHO) cell mutants, Z65, Z24/ZP107, ZP92, ZP105/ZP139, ZP109, ZP110, ZP114. Two peroxin cDNAs, PEX2 and PEX6, were first cloned by genetic phenotype-complementation assay using Z65 and ZP92, respectively, and were shown to be responsible for peroxisome biogenesis disorders (PBD) such as Zellweger syndrome, of CG-F (the same as CG-X in U.S.A.) and CG-C (the same as CG-IV), respectively. Pex2p is a RING zinc finger membrane protein of peroxisomes and Pex6p is a member of the AAA ATPase family. We likewise isolated PEX12 encoding a peroxisomal integral membrane protein in the RING family, by functional complementation of ZP109, demonstrating PEX12 to be responsible for CG-III PBD. We also cloned PEX1 by screening of human liver cDNA library, using ZP107. PEX1 mutation was delineated to be the genetic cause of PBD in the most highest incidence group, CG-E (the same as CG-I). Moreover, we recently found that Pex5p is involved in transport of not only PTS1- but also PTS2-protein, distinct from yeast Pex5p, using PEX5-defective ZP105 and ZP139. Thus, CHO cell mutants defective in peroxisome biogenesis are indeed shown to be very useful for the studies of peroxisome assembly and delineating pathogenic genes in PBD. Furthermore, we have isolated novel CGs of CHO mutants, ZP119 and ZP126.

Gene Expression Regulation↗
PubMed2000

[Evaluation of technetium-99m-MIBI scintigraphy in metastatic differentiated thyroid cancer--comparison study with 131I and 201Tl].

Detectability of metastasis in differentiated thyroid cancer using technetium-99m-methoxyisobutyl isonitrile (99mTc-MIBI) was compared with that of 131I and 201Tl. Forty patients after total thyroidectomy were evaluated. The scan results were compared with those of 131I and 201Tl whole body scintigraphy per patient. The positive rate was 68% in 99mTc-MIBI, 84% in 131I, 60% in 201Tl respectively. As to the lymph node metastasis, the positive rates were 56% in 99mTc-MIBI, 78% in 131I, 39% in 201Tl. In lung metastasis, the positive rate was 46% in 99mTc-MIBI, 82% in 131I and 55% in 201Tl. Serum thyroglobulin (Tg) was significantly higher in 201Tl and/or 99mTc-MIBI positive group compared to that of negative group independent of 131I scan results. Although the detectability of both 99mTc-MIBI and 201Tl were inferior to that of 131I, 9 to 22% of metastasis were detected only by these radiopharmaceuticals. Both 99mTc-MIBI and 201Tl, therefore, should be used in cases with high serum Tg even with negative 131I uptake. Basing on the fact there was no prominent difference between 99mTc-MIBI and 201Tl in the detectability of metastasis, 99mTc-MIBI might be more suitable tracer because of better quality image.

Adult↗
PubMed2000

Changes in microbial flora in neutropenic patients with hematological disorders after the Hanshin-Awaji earthquake.

The earthquake that struck the Hanshin-Awaji district on January 17, 1995, was one of the most destructive to occur in Japan. We analyzed the changes in microorganisms isolated from patients with hematological disorders in relation to this earthquake. We reviewed a total of 4137 microbial cultures obtained over 1-year periods before and after the earthquake. There were 123 neutropenic patients admitted during the study period (54 before the earthquake and 69 afterwards). No significant differences in clinical characteristics and underlying diseases were found between the 2 groups. Polynomial analysis revealed a significant increase in the isolation of Candida albicans, Candida glabrata, and Pseudomonas aeruginosa from sputum and stool cultures after the earthquake. These microorganisms increased markedly in patients from severe earthquake-damaged areas. In neutropenic patients with hematological disorders, microbial isolates changed significantly after the Hanshin-Awaji earthquake. These changes may have been related to physical and emotional stress, as well as to the deterioration of environmental factors such as food, air, and water.

Adolescent↗
PubMed2000

[Impending paradoxical embolism visualized by echocardiography combined with pulmonary embolism: a case report].

A 43-year-old man was admitted to our hospital complaining of dyspnea on exertion and dizziness. Transthoracic echocardiography revealed a mobile mass (3.5 x 1.0 cm) attached to the left atrial septum and transesophageal echocardiography showed the mass in the right atrium protruding through the patent foramen ovale into the left atrium. A mobile snake-like thrombus was apparent in the right atrium and right ventricle. The diagnosis was pulmonary embolism with impending paradoxical emboli.

Adult↗