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Biomedical subjects

Y Takagi

Publications and source records attributed to Y Takagi.

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

[Genome analysis of Helicobacter pylori by pulsed-field gel electrophoresis].

The molecular epidemiology of total 121 isolates of Helicobacter pylori was analyzed by pulsed-field gel electrophoresis method with restriction enzyme Spe I. Seventy-seven isolates were separated from the clinical samples, 36 isolates from pyloric antrum and the body of stomach of 18 patients and 8 isolates from pyloric antrum of 4 patients that include one colony before and after sterilizing treatment to each patient. Seventy-five in 77 isolates showed different genomic types respectively, and the other 2 isolates had the same genomic type and were suspected to be caused by intersective infection of medical workers or the instruments that used in examination because they were from patients who were examined by gastric microscope in same time and same laboratory. In isolates from 4 patients who were treated by sterilizing method, 2 patients showed same genomic types with that observed before the treatment, and one patient showed an incomplete treatment because the genomic type of its colony was is similar, and another patient could be infected again because its isolates showed different genomic type. In 18 patients whose isolates were separated from pyloric antrum and body of the stomach respectively to each person, isolates of 3 patients showed different genomic types in the two different part of stomach indicating that they had two and more clones of H. pylori.

Cloning, Molecular↗
PubMed2000

[Renal cell carcinoma in a patient with malignant lymphoma: a case report].

A 65-year-old woman was admitted for the treatment of malignant lymphoma. Computed tomography revealed a right renal tumor. After 3 cycles of CHOP (cyclophosphamide, adriamycin, vincristine, prednisone) chemotherapy, we performed right radical nephrectomy. The histopathological diagnosis was renal cell carcinoma. After nephrectomy she was treated with 3 cycles of CHOP chemotherapy and radiation therapy. She received no adjuvant therapy for renal cell carcinoma and had no recurrence after 8 months from the nephrectomy.

Aged↗
PubMed2000

[Good laboratory management and clinical laboratory physician].

Medical expenses have been increasing annually, and reducing expenses while maintaining effective medical care is desirable. In the late 1990s, Japanese government introduced policies expected to improve the medical security system. In the clinical laboratory field, some revisions such as packaging of certain tests(blanket test), separation between performance and interpretation fees for laboratory test, proper use of tumor markers, and additional fees for sample management. Japanese government also wants the clinical laboratory to return accurate laboratory test result to patients and physicians. Laboratory physicians have to make a great effort to manage clinical laboratories according to the guideline for GIOs of laboratory physicians from the Japanese Society of Clinical Pathology. The laboratory physician is the key person for good laboratory management.

Humans↗
PubMed2000

[Chemoradiotherapy with low-dose cisplatin and 5-FU for advanced esophageal cancer].

We evaluated the efficacy of chemoradiotherapy (CRT) for advanced esophageal cancer, from the view point of response. The relationship between chemo-radiosensitivity and dihydropyridine dehydrogenase (DPD), thymidylate synthase (TS), and p53 was investigated immunohistochemically. Thirteen patients with inoperable advanced esophageal cancer were involved in this study. CDDP of 10 mg/m2/day and 5-FU of 335 mg/m2/day were infused intravenously (day 1-5, day 15-19). Radiation was delivered concomitantly at a total dose of 30 Gy. Expressions of p53, DPD and TS were detected using immunohistology in the biopsy samples taken before CRT from 8 patients. Partial response was observed in 8 cases, no change in 4 cases, and progressive disease in one case. The overall response rate was 62%. The reduction rate was higher in tumors positive for p53 expression than in negative ones. The same was true for DPD and TS. The Treatment effect was more precisely predicted by combination of p53, DPD and TS. CRT with low-dose CDDP + 5-FU chemotherapy was effective and combination with p53, DPD, and TS might be a predictive marker for CRT in patients with advanced esophageal cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

[Habitual abortion and high frequency of low frequent X chromosome monosomy mosaicism: detection by interphase FISH analysis of buccal mucosa cells and lymphocytes].

FISH analysis using X alpha satellite probe was performed to the nuclei of lymphocytes obtained from fourteen women with having a history of habitual abortion for unknown causes(WHA) and from 65 normal control women(NW), in order to determine whether low frequency X monosomy mosaicism is one of the factors of habitual abortion. In parallel, the nuclei of buccal mucosa from 8 of WHA and 65 NW were also examined. Five hundreds of the interphase nuclei in each sample were observed. As results, the frequency of X monosomy in NW found in the lymphocytes or buccal mucosa was ranged from 0-3.2%(mean 1.59%, SD 0.69%) or from 0-3.2%(mean 1.24%, SD 0.85%), respectively. However, the occurrence of X monosomy in WHA was significantly higher compared with that of NW; i.e., 0.8-5.8%(mean 3.21%, SD 1.67) for lymphocytes, and 1.8-7.4%(mean 4.45%, SD 1.73%) for buccal mucosa. These results allowed us to define the reference intervals to discriminate WHA from NW were less than 2.97% or 2.94% for lymphocytes or buccal mucosa, respectively. Based on the reference intervals defined above, the high frequency of X monosomy mosaicism was actually found in 9 of 14 WHA. These results altogether strongly suggested that the low frequency X monosomy mosaicism was one of the factors of habitual abortion.

Abortion, Habitual↗
PubMed2000

[A case of left third nerve palsy and contralateral vertical gaze palsy with medial midbrain infarction].

An 81-year-old man developed oculomotor nerve palsy of the left eye and vertical gaze palsy of the right eye due to left medial midbrain infarction. His left eyelid was ptotic and the pupil was dilated. His right eye showed normal horizontal movement and Bell's phenomenon was preserved although the oculocephalic reflex was incomplete. There were no other abnormal neurological findings. The brain MRI revealed a high-intensity lesion in left medial midbrain on T2 weighted image. This lesion involved the oculomotor nerve nucleus, the interstitial nucleus of Cajal, and the rostral intersititial nucleus of the medial longitudinal fasciculus (riMLF). We thought that upward gaze palsy of the right eye was resulted from the infarction of the left riMLF or disruption of the axonal collateral of upward gaze fibers in the left oculomotor nucleus. Downward gaze palsy was resulted from the damage of the downward gaze fibers before their decussation, or the damage of the left interstitial nucleus of Cajal. This case provides evidence that unilateral lesion of the midbrain could cause contralateral vertical gaze palsy.

Aged↗
PubMed1999

Expression and distribution of redox regulatory protein, thioredoxin after metabolic impairment by 3-nitropropionic acid in rat brain.

Thioredoxin (TRX) is a small, multifunctional protein with a redox-active site and multiple biological functions that include reducing activity for reactive oxygen intermediates. We assayed TRX by immunohistochemical methods in the rat brain after intraperitoneal injection of 3-nitropropionic acid (3-NP), an irreversible inhibitor of succinate dehydrogenase. Systemic administration of 3-NP produced lateral striatal, hippocampal CA1 and CA3 lesions in the present study. The immunoreactivity for TRX was enhanced in hippocampal CA3, dentate gyrus and lateral striatum, but not detected in hippocampal CA1 subfield after 3-NP intoxication. The data suggest that TRX may play an important role in the pathogenesis of 3-NP neurotoxicity.

Animals↗
PubMed1999

Cloning and characterization of Dfak56, a homolog of focal adhesion kinase, in Drosophila melanogaster.

The focal adhesion kinase (FAK) protein-tyrosine kinase plays important roles in cell adhesion in vertebrates. Using polymerase chain reaction-based cloning strategy, we cloned a Drosophila gene that is homologous to the vertebrate FAK family of protein-tyrosine kinases. We designated this gene Dfak56 and characterized its gene product. The overall protein structure and deduced amino acid sequence of Dfak56 show significant similarity to those of FAK and PYK2. Dfak56 has in vitro autophosphorylation activity at tyrosine residues. Expression of the Dfak56 mRNA and the protein was observed in the central nervous system and the muscle-epidermis attachment site in the embryo, where Drosophila position-specific integrins are localized. The results suggest that like FAK in vertebrates, Dfak56 functions downstream of integrins. Dfak56 was tyrosine-phosphorylated upon integrin-dependent attachment of the cell to the extracellular matrix. We conclude that the Dfak56 tyrosine kinase is involved in integrin-mediated cell adhesion signaling and thus is a functional homolog of vertebrate FAK.

Amino Acid Sequence↗
PubMed1999

Effect of batroxobin on spontaneous echo contrast and hemorheology in left atrial appendage in atrial fibrillation assessed by transesophageal echocardiograpy.

Controversy exists regarding the effect of defibrination on spontaneous echo contrast and flow dynamics in left atrial appendage (LAA) in atrial fibrillation. We aimed to investigate the effect of batroxobin, which decreases plasma fibrinogen level, on the echo intensity of spontaneous echo contrast in LAA. In 36 patients with atrial fibrillation (duration 7 +/- 4 years), transesophageal echocardiography was performed at baseline and 24 hours after batroxobin administration (0.2 U/kg). At the orifice of the LAA, integrated backscatter of echo contrast and peak velocity of LAA emptying flow were measured. Plasma fibrinogen and whole blood viscosity were also measured. Fibrinogen and viscosity were significantly lower after batroxobin administration (96 +/-38 mg/dl and 4.35 +/- 0.56 cp) than those at baseline (320 +/- 61 mg/dl and 4.71 +/- 0.61 cp, both p <0.001). A significant positive correlation between changes in plasma fibrinogen and whole blood viscosity (r = 0.49, p = 0.002) was shown. The integrated backscatter significantly decreased from 14 +/- 3 to 12 +/- 3 decibels after batroxobin (p <0.001), and the changes in integrated backscatter and plasma fibrinogen was significantly correlated. Therefore, batroxobin administration improved blood rheology and decreased blood cell aggregation, which are effective in preventing left atrial thrombus formation.

Aged↗
PubMed1999

Enhanced GRK5 expression in the hearts of cardiomyopathic hamsters, J2N-k.

GTP binding protein-coupled receptor kinase 5 (GRK5) cDNA was cloned from the hearts of Syrian hamsters. The hamster GRK5 cDNA contained 1770 nucleotides encoding 590 amino acids, and the nucleotide sequence had 89.6% homology to the human homologue. An inbred cardiomyopathic hamster strain, J2N-k, was used to investigate the alteration of GRK5 mRNA expression in the setting of congestive heart failure. M-mode echocardiography revealed significant dilatation of the left ventricle and a decrease of left ventricular contractility in 20-week-old J2N-k hamsters compared with age-matched control hamsters, J2N-n. Semi-quantitative RT-PCR showed that GRK5 mRNA expression in the hearts of J2N-k was significantly higher than in those of J2N-n (J2N-k 60.3 +/- 13.3, J2N-n 25.8 +/- 17.2 arbitrary units, p < 0.005, n = 6 in each group). These results suggest that an enhanced GRK5 expression might play a role in the reduced responsiveness to catecholamines in failing hearts via beta-adrenergic receptor phosphorylation.

Aging↗
PubMed1999

Direct proteasome inhibition by clasto-lactacystin beta-lactone permits the detection of ubiquitinated p21(waf1) in ML-1 cells.

The ubiquitin proteasome pathway regulates the expression of major cellular regulatory proteins. The ubiquitin proteasome system has been demonstrated to be involved in the expression of the cyclin kinase inhibitor, p21. Ubiquitinated p21 is degraded immediately by 26S proteasome, therefore, the detection of p21 is difficult. We report here an improvement for the detection of ubiquitinated p21 using a proteasome inhibitor, clasto-lactacystin beta-lactone. A p21-enriched cell lysate is obtained by pretreating the cells with deferoxamine to induce p21 mRNA expression followed by treatment with 1x10(-6) M beta-lactone. The concentration of p21 from the cell lysate was performed using an anti-p21 antibody crosslinked to protein G Sepharose. Ubiquitinated p21 was detected on Western blots of the concentrated sample using an anti-ubiquitin antibody. This detection system will be used for further analysis of the regulation of p21 ubiquitination.

Acetylcysteine↗
PubMed1999

Identification of thioredoxin-binding protein-2/vitamin D(3) up-regulated protein 1 as a negative regulator of thioredoxin function and expression.

Recent works have shown the importance of reduction/oxidation (redox) regulation in various biological phenomena. Thioredoxin (TRX) is one of the major components of the thiol reducing system and plays multiple roles in cellular processes such as proliferation, apoptosis, and gene expression. To investigate the molecular mechanism of TRX action, we used a yeast two-hybrid system to identify TRX-binding proteins. One of the candidates, designated as thioredoxin-binding protein-2 (TBP-2), was identical to vitamin D(3) up-regulated protein 1 (VDUP1). The association of TRX with TBP-2/VDUP1 was observed in vitro and in vivo. TBP-2/VDUP1 bound to reduced TRX but not to oxidized TRX nor to mutant TRX, in which two redox active cysteine residues are substituted by serine. Thus, the catalytic center of TRX seems to be important for the interaction. Insulin reducing activity of TRX was inhibited by the addition of recombinant TBP-2/VDUP1 protein in vitro. In COS-7 and HEK293 cells transiently transfected with TBP-2/VDUP1 expression vector, decrease of insulin reducing activity of TRX and diminishment of TRX expression was observed. These results suggested that TBP-2/VDUP1 serves as a negative regulator of the biological function and expression of TRX. Treatment of HL-60 cells with 1alpha, 25-dihydroxyvitamin D(3) caused an increase of TBP-2/VDUP1 expression and down-regulation of the expression and the reducing activity of TRX. Therefore, the TRX-TBP-2/VDUP1 interaction may be an important redox regulatory mechanism in cellular processes, including differentiation of myeloid and macrophage lineages.

Animals↗
PubMed1999

Synthesis and antitumor activity of 5'-demethyl-5'-trifluoromethyl-daunorubicin and -doxorubicin.

The title compounds were prepared by coupling phenyl 4-O-acetyl-2,3,6-trideoxy-6,6,6-trifluoro-1-thio-3-trifluoroacetamido -alpha-L- and beta-L-lyxo-hexopyranoside with daunomycinone. The key step of this synthesis is the C-trifluoromethylation of a 1-protected 2,3-dideoxy-3-azido-D-erythro-pentodialdose, prepared from 2-deoxy-D-erythro-pentose, to give a 6,6,6-trifluoro-L-lyxo-hexose derivative. The synthetic products showed higher cytotoxicity than doxorubicin against most of the human tumor cell lines tested in vitro, possibly by the effect of the CF3 group at C-5'.

Antineoplastic Agents↗
PubMed1999

Proliferation of neuronal precursor cells in the dentate gyrus is accelerated after transient forebrain ischemia in mice.

We investigated the proliferation of neuronal progenitor cells by labeling dividing cells by systemic application of the thymidine analog 5-bromodeoxyuridine (BrdU) during transient forebrain ischemia in mice. At 3 (n=6), 7 (n=6), 10 (n=6), and 17 days (n=6) after reperfusion, BrdU-labeled cells were detected in the dentate gyrus and paraventricle lesion. After ischemia-reperfusion, BrdU-labeled cells in the dentate gyrus significantly increased in number but not in the paraventricle lesion. These observations may help to clarify the mechanism of functional recovery after stroke.

Animals↗
PubMed1999

Localized expression of aromatase in human vascular tissues.

The atheroprotective effects of estrogen are well established and the presence of an estrogen receptor in vascular tissues has recently been reported. Therefore, we investigated the localization of the estrogen-producing enzyme aromatase in vascular tissues to assess the possible contribution of endocrine, paracrine, and autocrine modes of action. Aromatase was found in human vascular smooth muscle cells (SMCs) but not in endothelial cells on in situ hybridization. These observations were further supported by quantitative analysis of aromatase mRNA and the activity in 15 human vascular specimens. Only trace levels of expression were detected in the 3 infants examined, whereas 0.0088 to 0.0806 amol/ microg RNA of aromatase mRNA and 12.9 to 122.3 fmol. h-1. mg-1 protein of the activity were detected in 12 of the adult individuals. The switching of tissue-specific exon 1 of the human aromatase gene was also observed in some cases. Aromatase was found to be expressed only in cultured SMCs and not in cultured endothelial cells of human aorta and pulmonary artery and to be regulated through dexamethasone and the signaling pathways of protein kinase A and C. Study results revealed the localized expression of aromatase in vascular SMCs, which indicated a possible direct action of locally produced estrogen in an autocrine or paracrine manner, with possible cross talk between smooth muscle and endothelial cells.

Adolescent↗
PubMed1999

Localization of glutaredoxin (thioltransferase) in the rat brain and possible functional implications during focal ischemia.

We investigated the distribution of glutaredoxin (GRX, thioltransferase) in the rat brain using the in situ hybridization and immunohistochemical methods. GRX mRNA and GRX were expressed widely in the rat brain. The endothelial cell, tanycyte and ependymal cell expressed GRX mRNA and GRX protein. Neurons in various regions also showed GRX mRNA and GRX. Among them, pyramidal neurons in hippocampal CA3 region expressed a higher level of GRX mRNA. In addition, GRX mRNA signals were reduced after middle cerebral artery occlusion. Immunohistochemical analysis for GRX also revealed that GRX was reduced after ischemia. Northern blot analysis also showed that GRX mRNA from ischemic hemispheres decreased after ischemia. This reduction was parallel with the neuronal damage. This observation indicated that the maintenance of GRX and the redox regulating system was important for neuronal survival against oxidative stress.

Animals↗