Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 325 records · Page 18Linked to original sources

PubMed1999

X chromosome territories in human female lymphocytes.

We developed an improved bromodeoxyuridine (BrdU)-DNA assay procedure for flow cytometric analysis. Which makes possible cytochemical investigation against cells after BrdU-DNA assay, such as immunochemical staining or in situ hybridization. Using this method, we performed fluorescence in situ hybridization (FISH) technique using DNA probes that recognize whole X chromosome of human lymphocytes in peripheral blood (resting cells) and cultured cells stimulated by phytohemagglutinin (PHA) (proliferative cells). Cultured cells were fractionated precisely into each stage of cell cycle by cell sorter after flow cytometric analysis. Following FISH procedure, the cells were examined for the volumes of two X chromosome territories in the nuclei using the optical section images on a confocal laser scanning microscope (CLSM). And we analyzed the variation in the volume ratio (R) of two X chromosome territories at different stages in cell cycle. Our data indicated that there were no significant difference between the volume of two X chromosome territories in female human lymphocytes at resting (G0) stage. Furthermore, they also showed no significant alternation throughout the cell cycle. These results may challenge the traditional concepts for inactivated chromosome in two points. First, the inactivated X chromosome is more decondensed throughout the cell cycle than previously thought. Second, although the inactivated X chromosome appears more decondensed during its self replication it dose not bring a great change in the volume of its territory.

Cells, Cultured↗

PubMed1999

[Usefulness of helical scanning CT in assessment of left ventricular papillary muscle contractility].

Three-dimensional data on the left ventricle at quasi-end-diastole and quasi-end-systole were acquired by helical scanning CT in 12 patients. Short axial images of the left ventricle and long axial images of the papillary muscle were created using multiplanar reconstruction. Left ventricular dimensions and the length of the papillary muscle were measured, and fractional shortening of the papillary muscle was calculated. There was a good correlation between left ventricular dimensions measured by echocardiogram and helical scanning CT (end-diastole: r = 0.94: end-systole: r = 0.86; fractional shortening of left ventricular dimension: r = 0.84). Papillary muscle fractional shortening was 6.3% in the ischemic group and 21.5% in the non-ischemic group (p < 0.005). Helical scanning CT is clinically useful for the assessment of left ventricular papillary muscle function.

Adult↗

PubMed1999

[Safety of continuous epidural anesthesia during heart surgery--change of coagulation-fibrinolysis under heparinization].

To confirm the safety of continuous epidural anesthesia during extracorporeal circulation under heparinization, we investigated epidural hematoma formation following the cardiopulmonary bypass in both humans and dogs. In fifteen dogs, divided into three groups, heparin was administered at the dose of 300, 600, or 900 U.kg-1, respectively. In fourteen patients, a dose of 300 U.kg-1 haparin was administered for cardiopulmonary bypass. Although blood coagulation-fibrinolysis dropped into abnormal ranges following heparinization, no epidural hematoma was observed in dog and no patient revealed spinal complication associated with epidural hematoma. These data indicate that continuous epidural anesthesia would be a safe tool for intraoperative anesthesia even during extracorporeal circulation under heparinization.

Adolescent↗

PubMed1999

[Inflammatory pseudotumor of the lung].

The patient was a 76-year-old man whose chief complaint was a dry cough. His chest X-ray film revealed a large hazy shadow with unclear margin in the left upper lobe. Bronchiolitis obliterans organizing pneumonia was initially diagnosed because transbronchial lung biopsy (TBLB) specimens showed organizing pneumonia with no evidence of malignancy. However, because the hazy shadow increased gradually in size despite steroid therapy. TBLBs were performed several more times to confirm the diagnosis. The last TBLB specimen showed proliferation of fibroblasts and mononuclear cells, with marked infiltration mainly of plasma cells 12 months after the initiation of steroid therapy. Because we were unable to obtain a histological diagnosis by bronchofiberscopy, a left upper lobectomy was preformed and the lesion resected. Histology disclosed inflammatory pseudotumor of a lymphoplasmacytic type with organizing pneumonia. The results of an immuno-histochemical examination confirmed that the proliferating plasma cells were polyclonal. These findings suggest that inflammatory pseudotumors should be taken into account by differential diagnoses of cases of organizing pneumonia that are resistant to steroid therapy.

Aged↗

PubMed1999

Usefulness of the pedicled omental graft in thoracic surgery.

A retrospective evaluation on the usefulness of the pedicled omental graft (POG) in treating problems associated with thoracic surgery is reported. The omentum has been long used to manage numerous intra-abdominal problems because of its excellent blood supply that could limit the spread of infection. The POG finds even greater application in extraperitoneal use because it is able to extend to all areas of the thorax. In this study, we reviewed 25 patients with omentopexy cases in our thoracic surgery unit over the last 19 years. Indications and usage of the POG were divided into two categories. As a preventive measure, the POGs were used to wrap tracheal and bronchial anastomoses. As a corrective treatment, the POGs were used to wrap perforated esophageal lesions and bronchial stumps and cover postoperative bronchial and pulmonary fistulas, repair chest walls, fill empyema cavities, and control osteomyelitis in the sternum and ribs. Uneventful and successful treatments were obtained in 22 cases (88%). Two patients died due to multiple organ failure followed by sepsis, and another due to respiratory failure. The POG was considered to be effective and useful in treating both potential and existing conditions often encountered in thoracic surgery.

Adult↗

PubMed1999

Clinical and biological aspects of acute lymphoblastic leukemia in 62 infants: retrospective analysis of the Tokyo Children's Cancer Study Group.

BACKGROUND: As a first step to formulate a new treatment strategy for refractory acute lymphoblastic leukemia (ALL) in infants, clinical results and immunophenotypic and cytogenetic data were analyzed and compared with those from overseas. METHODS: There were 62 infants with ALL who were treated between 1977 and 1995 at 30 institutions affiliated with the Tokyo Children's Cancer Study Group. Clinical and laboratory data obtained from these infants (all under 1 year of age) were retrospectively studied. RESULTS: The morphological diagnoses were FAB-L1 for 51 patients (82.2%) and FAB-L2 for 11 patients (17.8%). Hepatomegaly and splenomegaly were found in 40 (70.0%) and 40 patients (68.3%), respectively. The mean (+/- SEM) leukocyte count at diagnosis was 205,900 +/- 35,700/microL. The involvement of the central nervous system was evident in nine of 36 patients who were subjected to lumbar puncture, while three of these nine patients were free of neurological symptoms at diagnosis. Thirty-one patients (55.4%) were CD10 negative and 14 (25.0%) were CD10 positive. Thirty-one of 47 patients (65.9%) exhibited chromosomal abnormalities, including 28 patients (59.6%) with 11q23 abnormalities. Rearrangements in the MLL gene were found in nine of 13 infants (69.2%) examined. Translocation of 11q23 and/or MLL gene rearrangement (11q23/MLL) was significantly associated with the absence of the CD10 antigen. Hyperleukocytosis of more than 50,000/microL and 11q23/MLL gene rearrangements were related to a poor prognosis. The probability of an event-free survival in 62 infants was 13.1 +/- 4.8% at 48 months. CONCLUSIONS: New therapeutic strategies and large-scale cooperative prospective trials are needed to improve the prognosis of ALL in infants.

Chromosomes, Human, Pair 11↗

PubMed1999

Binocular depth-from-motion in infantile and late-onset esotropia patients with poor stereopsis.

PURPOSE: There are at least two possible ways to detect motion-in-depth binocular without monocular cues: the binocular disparities at different times and a mechanism that detects interocular velocity differences. The perception of interocular velocity differences (Binocular depth-from-motion [BDFM]) depends on the relative velocity of the images on the retina of the left and right eyes, and this information can be experienced by normal and some strabismic patients. The purpose of this study was to determine the characteristics of esotropic patients who have BDFM but have poor stereopsis. METHODS: Forty-one infantile and 28 late-onset esotropia patients with poor stereopsis were studied. Dynamic stereopsis and BDFM were tested with computer-generated random dot stereograms and kinematograms. The correlations between BDFM and other binocular functional tests were determined. RESULTS: A total of 31 (44.9%) patients, 15 (36.5%) of the infantile and 16 (57.1%) of the late-onset esotropia group, passed the BDFM test. None of these patients passed the random dot stereo test under static or dynamic conditions. Fusion of the Worth four dot test at near 0.3 m was correlated with the presence of BDFM. Three of the 15 infantile and 10 of the 16 late-onset esotropic patients with positive BDFM showed gross stereopsis as measured by the Titmus Fly. The angle of strabismus was significantly smaller in the patients with positive BDFM for the infantile and the late-onset esotropia groups. CONCLUSIONS: BDFM was present in about half of the esotropic patients who do not have fine stereopsis. Ocular alignment within 10 to 15 prism diopters is an important factor in obtaining BDFM. Strabismus surgery still provides some binocular benefit for infantile esotropia patients who were bypassed for early surgery. Separate mechanisms may underlie static stereopsis and BDFM.

Adolescent↗

PubMed1999

[A long-survival case of gastric cancer with multiple liver metastasis: usefulness of intraoperative multimodality therapy and post-operative intra-arterial chemotherapy for liver lesions].

A 62-year-old man was found to have advanced cancer of the gastric cardia with multiple liver metastasis. Total gastrectomy was performed, and 11 hepatic lesions were simultaneously treated by intraoperative multimodality therapy. The therapy included hepatic resections for seven easily-resectable lesions, microwave coagulation therapy for two lesions, and ethanol injection therapy for two. Post-operative intra-arterial infusion of 1,000 mg of 5-FU was performed weekly or every two weeks through the hepatic artery using a reservoir. No recurrence was found during the follow-up period of 35 months. When local control is obtained during surgery in patients with gastric cancer with multiple liver metastasis, intraoperative multimodality therapy and post-operative intra-arterial chemotherapy should be performed for liver lesions.

Adenocarcinoma↗

PubMed1999

[Stent intubation for the airway stenosis under PCPS].

Placement of stents for the tracheal or carinal stenosis have a meaning of maintaining the airway. Failure of the stenting causes death. In cases of severe airway stenosis and low pulmonary function, the pulmonary support method should be performed instead of intubation and mechanical ventilation. Generally, PCPS (percutaneous cardio-pulmonary support system) is used as a pulmonary support. This method was very useful to place stents for airway stenosis. We concluded that PCPS was useful in emergency cases, and in cases of severe fixed type airway stenosis and low pulmonary function it had be on stand-by.

Cardiopulmonary Bypass↗

PubMed1999

Immunolocalization and gene expression of matrilysin during corneal wound healing.

PURPOSE: To investigate the protein level of matrilysin and stromelysin-1 and the gene expression of matrilysin in rat corneas after excimer keratectomy using immunofluorescence staining, reverse transcriptase-polymerase Chain Reaction (RT-PCR), and in situ hybridization. METHODS: Rat corneas were treated with 3-mm excimer laser keratectomy (193-nm ArF). Unwounded corneas served as controls. Confocal microscopy was used to immunolocalize matrilysin protein at 6 hours, 1 day, 3 days, 1 week, 4 weeks, and 8 weeks after surgery. RT-PCR was performed to analyze matrilysin mRNA in unwounded controls and in 3-day wounded corneas. In situ hybridization was performed to localize matrilysin mRNA. RESULTS: Matrilysin was immunolocalized to the epithelial layers of unwounded and wounded corneas, predominantly to the leading edge at 6 hours and 1 day after wounding and to the epithelial layer at 3 to 7 days after surgery. Stromelysin-1 was expressed in the deep stromal layer in the first 3 days after wounding and in the area of newly synthesized stromal matrix 1 week after surgery. Upregulation of matrilysin expression 3 days after wounding was confirmed by RT-PCR. In situ hybridization revealed that the gene expression of matrilysin in rat corneas was upregulated during the migration phase (6 hours, 1 day) and that matrilysin mRNA was predominantly localized to the basal cell layers during the subsequent cell proliferation phase (7 and 14 days). CONCLUSIONS: Basal epithelial cells express matrilysin during the migration proliferation phase of corneal wound healing after excimer keratectomy.

Animals↗

PubMed1999

Severe occlusive carotid artery disease: hemodynamic assessment by MR perfusion imaging in symptomatic patients.

BACKGROUND AND PURPOSE: Cerebral hemodynamic status has been reported to influence the occurrence and outcome of acute stroke. The purpose of this study was to assess hemodynamic compromise in symptomatic patients with severe occlusive disease of the carotid artery by the use of echo-planar perfusion imaging. METHODS: Spin-echo echo-planar perfusion imaging was performed in 11 patients (two had bilateral disease) with severe stenosis or occlusion of the carotid artery who had experienced either a recent transient ischemic attack or minor stroke. Relative cerebral blood volume (rCBV) maps and relative mean transit time (rMTT) maps were generated from the time-concentration curve. Findings on T2-weighted images, angiograms, rCBV maps, and rMTT maps were compared and assessed qualitatively and quantitatively. RESULTS: Although the abnormalities on T2-weighted images were absent, minimal, and/or unrelated to the degree of stenosis or collateral circulation, rMTT maps showed much larger and more distinct perfusion abnormalities along the vascular distribution of the affected vessels in all 13 vascular territories of the 11 patients. Despite obvious abnormalities on rMTT maps, none of the patients had evidence of decreased rCBV in the affected brain tissue (increased in three, normal in eight). A statistically significant difference in rMTT values was found between the affected and unaffected brain tissue, whereas no significant difference was seen in rCBV values. CONCLUSION: Echo-planar perfusion imaging is a noninvasive and rapid method for evaluating the hemodynamics in severe occlusive carotid artery disease and the compensatory vascular changes, and it may be useful in patient management.

Adult↗

PubMed1998

The Dictyostelium developmental cDNA project: generation and analysis of expressed sequence tags from the first-finger stage of development.

In an effort to identify and characterize genes expressed during multicellular development ill Dictyostelium, we have undertaken a cDNA sequencing project. Using size-fractionated subsets of cDNA from the first finger stage, two sets of gridded libraries were constructed for cDNA sequencing. One, library S, consisting of 9984 clones, carries relatively short inserts, and the other, library L, which consists of 8448 clones, has longer inserts. We sequenced all the selected clones in library S from their 3'-ends, and this generated 3093 non-redundant, expressed sequence tags (ESTs). Among them, 246 ESTs hit known Dictyostelium genes and 910 showed significant similarity to genes of Dictyostelium and other organisms. For library L, 1132 clones were randomly sequenced and 471 non-redundant ESTs were obtained. In combination, the ESTs from the two libraries represent approximately 40% of genes expressed in late development, assuming that the non-redundant ESTs correspond to independent genes. They will provide a useful resource for investigating the genetic networks that regulate multicellular development of this organism.

Animals↗

PubMed1998

The choleretic effects of N-acetylglucosaminides, major urinary metabolites of ursodeoxycholic acid, in bile fistula rats.

We investigated the effects of three bile acids conjugated with N-acetylglucosamine, ursodeoxycholate N-acetylglucosaminide, tauroursodeoxycholate N-acetylglucosaminide and glycoursodeoxycholate N-acetylglucosaminide, on bile flow and biliary excretion of various markers in comparison with ursodeoxycholic acid, tauroursodeoxycholic acid and glycoursodeoxycholic acid in bile fistula rats. These bile acids were infused intravenously at a constant rate of 0.3 or 0.6 micromol/min/100 g b.w. for 2 h. All bile acids examined increased bile flow in a dose-dependent manner. In particular, ursodeoxycholate N-acetylglucosaminide has a longer-lasting effect after its infusion on bile flow than the other bile acids. Furthermore, these bile acids markedly increased biliary total bile acid excretion. At a higher dose level, the coefficient of determination (r2) between the biliary total bile acid excretion and bile flow for ursodeoxycholate N-acetylglucosaminide (r2 = 0.39) was lower than that for the other bile acids (r2 = 0.75-0.92). The ursodeoxycholate N-acetylglucosaminide, as well as tauroursodeoxycholic acid, glycoursodeoxycholic acid, tauroursodeoxycholate N-acetylglucosaminide and glycoursodeoxycholate N-acetylglucosaminide, was mostly excreted in an unchanged form in bile, whereas ursodeoxycholic acid was excreted as a conjugate with taurine. The three N-acetylglucosaminides as well as ursodeoxycholic acid, tauroursodeoxycholic acid and glycoursodeoxycholic acid significantly increased the biliary excretion of cholesterol, phospholipid, bilirubin and total Ca2+. In contrast, the N-acetylglucosaminides significantly decreased in biliary bicarbonate concentration, whereas ursodeoxycholic acid significantly increased biliary bicarbonate concentration. However, tauroursodeoxycholic acid and glycoursodeoxycholic acid did not significantly change the biliary bicarbonate concentration. The results indicate that N-acetylglucosaminides have a choleretic effect in bile fistula rats. Our present study also demonstrates that N-acetylglucosaminides, but not ursodeoxycholic acid, tauroursodeoxycholic acid or glycoursodeoxycholic acid, can significantly reduce the biliary bicarbonate concentration. Furthermore, our findings suggest that ursodeoxycholate N-acetylglucosaminide may partly exert a choleretic effect via mechanisms different from those of the other bile acids.

Animals↗

PubMed1998

Identification of a novel adenylate kinase system in the brain: cloning of the fourth adenylate kinase.

We identify a novel subtype of adenylate kinase, which is the 4th adenylate kinase (AK4), in the vertebrate. AK4 mRNA is expressed in the mammalian central nervous system in a region-specific manner from the middle stage of embryogenesis to the adulthood in the rodent. The presence of three isozymes of adenylate kinase (AK1, AK2 and AK3) that maintains the homeostasis of adenine and guanine nucleotide composition has been reported in the vertebrate. Obtained mouse AK4 cDNA is 3667 bp in size. The predicted open reading frame consists of 223 amino acid residues. Rat AK4 cDNA is also obtained, and the predicted open reading frame is the same length as that of the mouse. The predicted rat AK4 molecule shows 97.8% homology with mouse AK4. Rat AK4 protein is distinct from rat AK3, 53.8% homologous with rat AK3, although the adenylate kinase signature and the mitochondrial energy transfer protein signature are found in both sequences. Interestingly, rat AK4 is 89.2% homologous with the human AK3 over 223 amino acid residues and rat AK3 is 53.7% homologous with the human AK3 indicating that the reported human AK3 actually belongs to the AK4 group (therefore, it should be referred to as human AK4). Although the sequence of AK4 is most similar to that of AK3 among the AK isozymes, its in vivo expression is completely different from AK3; AK4 mRNA is expressed in the pyramidal cells in the hippocampus (mainly in the subfield CA3), the granular cells in the cerebellum, nasal neuroepithelium and the liver while AK3 mRNA is expressed ubiquitously in the body. It is probable that AK4 acts on the specific mechanism of energy metabolism rather than control of the homeostasis of the ADP pool ubiquitously.

Adenylate Kinase↗

PubMed1998

Interaction of Doc2 with tctex-1, a light chain of cytoplasmic dynein. Implication in dynein-dependent vesicle transport.

Doc2 has one Munc13-interacting domain at the N-terminal region and two C2-like domains interacting with Ca2+ and phospholipid at the C-terminal region. Doc2 consists of two isoforms, Doc2alpha and -beta. Doc2alpha is specifically expressed in neuronal cells and implicated in Ca2+-dependent neurotransmitter release, whereas Doc2beta is ubiquitously expressed and its function is unknown. We show here that both Doc2alpha and -beta interact with rat tctex-1, a light chain of cytoplasmic dynein, in both cell-free and intact cell systems. Overexpression of the N-terminal fragment of Doc2 containing the tctex-1-interacting domain induces changes in the intracellular localization of cation-independent mannose 6-phosphate receptor and its ligand, cathepsin D, which are transported from trans-Golgi network to late endosomes. Overexpression of the C-terminal fragment containing two C2-like domains shows the similar effect, but to a lesser extent, whereas overexpression of full-length Doc2 or the C-terminal fragment of rabphilin3 containing two C2-like domains does not show this effect. Because dynein is a minus-end-directed microtubule-based motor protein, these results suggest that Doc2, especially Doc2beta, plays a role in dynein-dependent intracellular vesicle transport.

Amino Acid Sequence↗

PubMed1998

Outcomes of stent-graft treatment of false lumen in aortic dissection.

BACKGROUND: Stent-graft treatment for aortic disease promises to lead to a less invasive therapy than conventional surgical therapy. However, this treatment has not been established as a therapy for aortic dissection. The aim of this study was to examine the effect of stent-graft treatment of aortic dissection, as measured by follow-up data on entry site closure, clotting in the false lumen, and the outcome of the false lumen from the acute to chronic phase after operation. METHODS AND RESULTS: We used a stent-graft of our own design to close the entry site of aortic dissection in 21 cases: 9 were acute (< 14 days), 8 subacute (< 6 months), and 4 chronic (> 6 months). Nine were type A and 12 were type B. In 15 cases, the stent-graft was inserted through the transverse arch, which had been surgically opened under median sternotomy. In the other 6 cases, the stent-graft was inserted by means of a transcatheter through a femoral artery. Using computed tomographic scans, we followed and examined clot formation in the false lumen and reduction in size of the false lumen at 3 levels: at the level of maximum aortic diameter, at the distal end of the stent-graft, and 50 mm distal to the stent-graft. The entry sites were successfully closed in 19 cases (90.4%); in the remaining 2 (both treated with a transcatheter) there was perigraft leakage into the false lumen. The hospital mortality rate of these stent-graft treatments was 14.3% (3 of 21). At 2 weeks after operation, the false lumen had completely clotted, respectively, in 100%, 77%, and 38% of cases at the 3 measurement levels. Substantial shrinkage (> 50% in diameter) of the false lumen at 6 months after the operation was observed in 72%, 60%, and 38% of cases at the respective levels. Shrinkage of the false lumen was particularly enhanced in patients treated within 6 months from the onset of dissection: The false lumen shrank by > 50% in 93%, 75%, and 50% of patients. CONCLUSIONS: In cases of aortic dissection, the stent-graft is an effective tool for closing the entry site and promoting clot formation in the false lumen and for reducing the size of the false lumen within 6 months of the onset of dissection if the entry site has been closed.

Adult↗

PubMed1998

Excellent acceleration of the Diels-Alder reaction by microwave irradiation for the synthesis of new fluorine-substituted ligands of NMDA receptor.

A series of 6,11-ethanobenzo[b]quinolizinium derivatives was synthesized through the Diels-Alder reaction between azoniaanthracne and the corresponding 1,1-disubstituted olefin. After a systematic investigation for achieving rapid synthesis, it was found that the reaction is accelerated in polar media such as H2O and trifluoroethanol. In particular, excellent acceleration was effected by microwave irradiation. The new fluorine-substituted ligands thus obtained exhibited potential affinity toward NMDA receptors.

Animals↗

PubMed1998

Contribution to substrate recognition of two aromatic amino acid residues in putative transmembrane segment 10 of the yeast sugar transporters Gal2 and Hxt2.

The comprehensive study of chimeras between the Gal2 galactose transporter and the Hxt2 glucose transporter of Saccharomyces cerevisiae has shown that Tyr446 is essential and Trp455 is important for galactose recognition by Gal2. Consistent with this finding, replacement of the corresponding Phe431 and Tyr440 residues of Hxt2 with Tyr and Trp, respectively, allowed Hxt2 to transport galactose, suggesting that the two amino acid residues in putative transmembrane segment 10 play a definite role in galactose recognition (Kasahara, M., Shimoda, E., and Maeda, M. (1997) J. Biol. Chem. 272, 16721-16724). Replacement of Trp455 of Gal2 with any of the other 19 amino acids was shown to reduce galactose transport activity to between 0 and <20% of that of wild-type Gal2. The role of Phe431 in Hxt2 was similarly studied. Other than Phe, only Tyr at position 431 was able to support glucose transport activity, at the reduced level of <20%. In contrast, replacement of Tyr440 of Hxt2 with other amino acids revealed that most replacements, with the exception of Pro and charged amino acids, supported glucose transport activity. The importance of residue 431 in sugar recognition was more pronounced in a modified Hxt2 in which Tyr440 was replaced with Trp. Glucose transport was supported only by the aromatic amino acids Phe, Tyr, and Trp at position 431, and galactose transport was supported only by Tyr. These results suggest that an aromatic amino acid located in the middle of transmembrane segment 10 (Tyr446 in Gal2 and Phe431 in Hxt2) plays a critical role in substrate recognition in the yeast sugar transporter family to which Gal2 and Hxt2 belong.

Amino Acid Sequence↗