Biomedical subjects

T Arai

Publications and source records attributed to T Arai.

At least 325 records · Page 18Linked to original sources

PubMed1998

Histological evidence for cell proliferation activity in cystic tumor (endodermal heterotopia) of the atrioventricular node.

Cystic tumor (endodermal heterotopia) of the atrioventricular (AV) node in a 95-year-old female is described. Electrocardiograms showed complete AV blockage with a narrow QRS morphology resulting from the long-standing first degree of AV blockage since age 61. A cardiac pacemaker was implanted at age 83. The patient died of pneumonia at age 95. Autopsy demonstrated a normal heart weight (320 g), normal coronary artery and normal myocardium. Histological examination of the conduction system revealed a marked fibrotic sinoatrial (SA) node and a cystic lesion in the lower right atrium, including the approaches to the AV node. The bundle of His and its branches were completely intact. Cellular nests and cystically dilated tubules were scattered within a loose tissue stroma, which measured 18 x 12 x 5 mm. There were several mitotic figures among the tubules, as well as nuclear fragments similar to apoptotic bodies and exfoliation of the tumor cells. Immunohistochemical studies demonstrated a positive reaction for epithelial membrane antigen, carcinoembryonic antigen, CA19-9, cytokeratin and secretory component in the tubular cells, and a negative reaction for thrombomodulin. Endocrine cells among the tubules were positive only for calcitonin and serotonin. Ultrastructurally, sparse microvilli and desmosome-like structures between the tumor cells were observed. These findings support that this lesion originates from the endoderm. Moreover, it is likely that progression in the degree of AV block may be explained by the cell proliferation activity of the tumor.

Aged↗

PubMed1998

Salmonella infection-induced non-responsiveness of murine splenic T-lymphocytes to interleukin-2 (IL-2) involves inhibition of IL-2 receptor gamma chain expression.

In a previous study we demonstrated that Salmonella typhimurium-induced immunosuppression involved T-cell non-responsiveness to interleukin-2 (IL-2). In this study we observed that Salmonella-induced T-cell non-responsiveness to IL-2 was not reversed completely by treatment with N(G)-monomethyl-L-arginine, which is known to inhibit nitric oxide (NO) secretion by macrophages in culture. Furthermore, when purified splenic T-lymphocytes from Salmonella-infected mice were activated with an anti-CD3 antibody, the responsiveness of these T-cells to IL-2 was suppressed significantly. Results of flow cytometric analysis using an anti-IL-2 receptor gamma chain (IL-2Rgamma) antibody showed that IL-2Rgamma expression in mitogen-activated T-cells was down-regulated by Salmonella infection. These results suggest that Salmonella infection-induced T-cell non-responsiveness to IL-2 involves a defective function of T-cells themselves and appears to be regulated by inhibition of IL-2Rgamma expression in T-cells.

Animals↗

PubMed1998

DNA sequencing of the gene encoding Salmonella typhimurium-derived T-cell inhibitor (STI) and characterization of the gene product, cloned STI.

In a previous study, we found a novel protein which inhibited T-cell responsiveness to interleukin-2 (IL-2) in Salmonella typhimurium and called it S. typhimurium-derived T-cell inhibitor (STI). In this study, we analyzed the DNA sequence of the gene encoding STI. The STI gene was cloned into a plasmid vector, pUC118, and expressed in Escherichia coli JM109. Like native STI, the cloned STI inhibited IL-2-dependent CTLL-2 cell growth. Furthermore, this growth inhibition involved down-regulation of IL-2 receptor expression. These results indicate that the cloned STI expressed in E. coli was identical to native STI. Sequencing revealed that the STI gene contained an open reading frame of 2298 base pairs encoding a precursor form of 765 amino acid residues (molecular mass 83605) that is processed into a mature form of 745 amino acid residues with molecular mass 81 548. Homology analysis revealed that its amino acid sequence was highly homologous with that of the beta-glucosidase of E. coli K-12. We designated the gene encoding STI sti.

Amino Acid Sequence↗

PubMed1998

[Real time observation of binding of measles virus to Vero cells and neutralization of measles virus by human immunoglobulin using optical biosensor--a new real time diagnosis system for viral infections].

An optical biosensor to monitor molecular intractions was developed. This system made possible to observe reactions with a few minutes. We tried to apply this system for rapid diagnosis of viral infections. Measles virus propagated in our laboratory and crude rabbit anti-measles antiserum were used. A commercially available human immunoglobulin was used as a representative of patient sera. A crude rabbit anti-measles antiserum was fixed on the reaction surface of aminosilane coated cuvette, and specific binding of measles virus to this antibody was monitored. Specific purified IgG antibody was known to give as high sensitivity as the conventional culture method. But the sensitivity by crude antibody was found to be 1/10 in the sensitivity. This might be caused by the masked effects on specific antibody to the contaminated high amounts of non-specific proteins. None purified polyclonal antisera for most of the viruses are commercially available, and 10-20 times highly concentrated antibody solutions could be used for this titrations. Estimated anti-measles antibody titer of the commercial available human immunoglobulin by biosensor system was found to be the same as that by the conventional culture method. It was suggested that 1 X 10(3) virus particles/ml in the test solutions could be detectable and titerable by using commercially available specific anti-viral antibody in real time, and the viral infections could be diagnosed within an hour.

Animals↗

PubMed1998

A new system for stringent, high-titer vesicular stomatitis virus G protein-pseudotyped retrovirus vector induction by introduction of Cre recombinase into stable prepackaging cell lines.

We report here on stable prepackaging cell lines which can be converted into packaging cell lines for high-titer vesicular stomatitis virus G protein (VSV-G)-pseudotyped retrovirus vectors by the introduction of Cre recombinase-expressing adenovirus. The generated prepackaging cell lines constitutively express the gag-pol genes and contain an inducible transcriptional unit for the VSV-G gene. From this unit, the introduced Cre recombinase excised both a neomycin resistance (Neo(r)) gene and a poly(A) signal flanked by a tandem pair of loxP sequences and induced transcription of the VSV-G gene from the same promoter as had been used for Neo(r) expression. By inserting an mRNA-destabilizing signal into the 3' untranslated region of the Neo(r) gene to reduce the amount of Neo(r) transcript, we were able efficiently to select the clones capable of inducing VSV-G at high levels. Without the introduction of Cre recombinase, these cell lines produce neither VSV-G nor any detectable infectious virus at all, even after the transduction of a murine leukemia virus-based retrovirus vector encoding beta-galactosidase. They reproducibly produced high-titer virus stocks of VSV-G-pseudotyped retrovirus (1.0 x 10(6) infectious units/ml) from 3 days after the introduction of Cre recombinase. We also present evidence that VSV-G-producing cells are still fully susceptible to transduction by VSV-G pseudotypes. However, in this vector-producing system, which regulates VSV-G pseudotype production in an all-or-none manner, the integration of vector DNA into packaging cell lines would be minimized. We further show that heparin significantly inhibits retransduction of VSV-G pseudotypes in the culture fluids of packaging cell lines, leading to a two- to fourfold increase in the yield of the pseudotypes after induction. This vector-producing system was very stable and should be advantageous in human gene therapy.

Animals↗

PubMed1998

Protein tyrosine phosphorylation mediates TNF-induced endothelial-neutrophil adhesion in vitro.

Proinflammatory cytokines initiate the vascular inflammatory response via the upregulation of adhesion molecules on the luminal endothelial surface. We investigated directly the role of protein tyrosine phosphorylation in the upregulation of the endothelial adhesion molecules, intercellular adhesion molecule 1 (ICAM-1) and E-selectin, and the consequent adhesion of neutrophils, after tumor necrosis factor (TNF)-alpha-stimulation of human aortic endothelial cells in vitro. Time- and dose-dependent TNF-alpha-stimulated ICAM-1 and E-selectin upregulation and neutrophil adhesion each were suppressed by tyrosine kinase inhibitors, including genistein (200 microM), but not genistein, its isoflavone analog without tyrosine kinase inhibitory activity. Tyrphostin AG 126, a synthetic selective tyrosine kinase inhibitor, also suppressed ICAM-1 and E-selectin upregulation and neutrophil adhesion, each in a dose-dependent manner, whereas tyrphostin AG 1288 had no effect. Tyrosine phosphorylation of two proteins (85 and 145 kDa in the cytoskeleton fraction) found minutes after TNF-alpha-stimulation was also inhibited by genistein. These findings suggest that, in endothelial cells, TNF-alpha upregulates ICAM-1 and E-selectin expression and consequent neutrophil adhesion via protein tyrosine phosphorylation.

Benzylidene Compounds↗

PubMed1998

Isolation of an Escherichia coli mutant which permits the high-level expression of a streptomycin-resistance gene derived from Pseudomonas aeruginosa.

Pretreatment with streptomycin at a low concentration influenced the susceptibility to streptomycin of a strain of Escherichia coli carrying a streptomycin-resistance plasmid, pSA1700, derived from Pseudomonas aeruginosa. This phenomenon was due to a mutation that occurred at about 10(-8)-10(-10) of frequency in a regulatory gene involved in gene expression on the chromosome of E. coli. A product encoded by the regulatory gene on the chromosome of E. coli might normally repress gene expression by binding to part of the promoter region of the streptomycin-resistance gene derived from P. aeruginosa.

Cloning, Molecular↗

PubMed1998

Effect of the carbamoyl group attached to an axial ligand portion of a novel bleomycin model on a dioxygen activating reaction.

A Fe complex of a novel bleomycin model compound bearing a diaminopropionamide (DAPA) moiety as the axial ligand and a long alkyl chain as the steric factor around the 6th coordination site promoted reversible redox reaction and exhibited high oxygen activating ability. Kinetic analysis of the redox reaction in the presence of dioxygen and a reducing agent revealed that the presence of the carbamoyl group on the DAPA moiety facilitates the oxygenation-activation process of the Fe(II) complex, and the reduction process of the resulting Fe(III) complex.

Bleomycin↗

PubMed1998

Intrapulmonary satellite nodule of lung cancer as a T factor.

OBJECTIVE: We conducted a validation of the treatment of satellite nodules in the UICC TNM classification of 1993 and 1997. PATIENTS AND METHODS: The clinical records of the 352 patients with T2-4 lung cancer who underwent curative resection were reviewed. The UICC classification of 1993 was used to classify the pathologic stage. No satellite nodule was found in 305 cases (PM0 group), 39 cases had a satellite nodule in the same lobe as that of the primary tumor (PM1 group), and 8 cases had a satellite nodule in another ipsilateral lobe (PM2 group). Outcome was compared based on the T classification. RESULTS: The differences of the survival rates between the PM0 and PM1 groups were not statistically significant for T2 and T3 cases. For T4 cases, the 5-year survival rate was 0% in the PM0 group, 33.3% in the PM1 group, and 0% in the PM2 group. CONCLUSION: It was appropriate for T2 and T3 cases that the rank of T classification was up-staged for a satellite nodule in the same lobe according to the 1993 classification. For T4 cases, however, the PM1 group had a significantly better outcome. If all PM1 cases with any T and N factor are included in T4 according to the 1997 classification, it may elevate the survival rate of T4 better than that of T4 by the former classification.

Adenocarcinoma↗

PubMed1998

Dibutyryl cyclic adenosine monophosphate protects mice against tumor necrosis factor-alpha-induced hepatocyte apoptosis accompanied by increased heat shock protein 70 expression.

Liver injury accompanied by apoptosis of hepatocytes was provoked in mice by an intravenous injection of recombinant tumor necrosis factor-alpha (rTNF-alpha) (1.0 microg/kg) together with an intraperitoneal injection of D-galactosamine (D-gal) (500 mg/kg). Injection of various doses of dibutyryl cAMP (DBcAMP) protected mice from TNF-alpha/D-gal-induced liver injury as assessed by serum alanine aminotransferase (ALT) levels, histological examination and DNA fragmentation. DBcAMP significantly enhanced the Hsp70 expression in the hepatocytes of D-gal/TNF-alpha-injected mice in close correlation with suppression of liver injury. DBcAMP induced Hsp70 expression in the hepatocyte in vitro. These results suggest that increase in Hsp70 expression by DBcAMP is involved in protective mechanisms by DBcAMP against TNF-alpha-induced liver injury in D-gal-sensitized mice.

Animals↗

PubMed1998

Bronchial asthma induced by rice.

A 43-year-old patient with rice-induced bronchial asthma was first admitted to our hospital for developing bronchial asthma induced by mite and house dust. At that time, there was no sign of allergic response to rice. Two years later, he was readmitted in an emergency state, with a severe attack of bronchial asthma. This time, however, the result of immunoglobulin E (IgE)-radioallergosorbent test (RAST) for rice was positive, with those to mite and house dust were unexpectedly negative. The causative factors and pathological mechanisms of various kinds of food allergies still remain unknown. The patient is now followed up in an ambulatory setting, and has been eating hypoallergenic rice with no bronchial asthma-induced attack. The present case, being an adult patient with severe grain-induced bronchial asthma previously allergic to mite and house dust, seems to be rather rare in the literature.

Adult↗

PubMed1998

[Studies of type I collagen related substances as bone metastatic markers of prostate carcinoma with special regard to serum carboxyterminal propeptide of type. I. Procollagen (PICP), cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and Urinary deoxypyridinoline levels].

BACKGROUND: To investigate if serum levels of carboxyterminal propeptide of type I procollagen (PICP), cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and urinary levels of deoxypyridinoline (D-Pyr) are useful markers of bone metastasis in patients with prostate carcinoma, we measured these markers in patients with untreated benign prostatic hyperplasia (BPH) and untreated prostate carcinoma (PCA). METHODS: Serum PICP, ICTP and urinary D-Pyr levels were determined in 53 patients; 16 patients with BPH, 15 patients with PCA without bone metastasis (stage A, B, C and D1) and 22 patients with PCA with bone metastasis (stage D2). At the same time correlations among these markers and serum total alkaline phosphatase (ALP) activity were studied. RESULTS: Serum PICP, ICTP and urinary D-Pyr levels in the PCA patients with bone metastasis were significantly higher than those of BPH. The serum levels of PICP in patients with PCA with bone metastasis group were significantly higher than those of without bone metastasis group. The serum levels of ICTP in patients with PCA without bone metastasis group were significantly higher than those of BPH group, while no significant difference was observed between PCA group with and without bone metastasis. In the PCA patients with bone metastasis, serum PICP and serum total alkaline phosphatase (ALP) activity were significantly correlated (r = 0.80). In these patients, serum ICTP and urinary D-Pyr levels were also significantly correlated (r = 0.70). CONCLUSION: These results suggest that serum PIPC, ICTP and urinary D-Pyr are the useful markers to quantitate bone metastasis in the patients with PCA. Moreover, the determination of serum ICTP levels may be significant for detecting occult bone metastasis in the patients with PCA.

Aged↗

PubMed1998

Ocular arterial flow hemodynamics in patients with diabetes mellitus.

The purpose of this study was to investigate ocular blood flow hemodynamics in patients with diabetes mellitus. We used color Doppler sonography, in 22 normal subjects and 52 patients with (n = 25) or without (n = 27) diabetic retinopathy, to determine blood flow velocities and the resistive index of the central retinal artery. The resistive index of the central retinal artery in patients with diabetic retinopathy (0.85 +/- 0.09) was significantly greater (P < 0.01) than that in normal subjects (0.72 +/- 0.08) and in patients without diabetic retinopathy (0.81 +/- 0.09). The resistive index of the central retinal artery in the patients without diabetic retinopathy was also significantly greater than that of normal subjects (P < 0.01). The resistive index of ocular arterial flow was increased in the patients with diabetes mellitus and further increased in the presence of retinopathy. Increased resistance in the peripheral ocular vascular bed contributes to diabetic retinopathy, and this change is present before the appearance of overt diabetic retinopathy.

Blood Flow Velocity↗

PubMed1998

The antibacterial activity of plaunotol against Staphylococcus aureus isolated from the skin of patients with atopic dermatitis.

Plaunotol was tested for possible antibacterial activity against twenty strains of methicillin-resistant Staphylococcus aureus (MRSA) and fourteen strains of methicillin-sensitive S. aureus (MSSA) which had been isolated from the skin of patients with atopic dermatitis under growth-promoting conditions. Plaunotol was effective against all strains tested. The dose of plaunotol for 50% inhibition of growth (ID50) ranged from 2.5 to 16 micrograms/ml for strains of MRSA and from 2.5 to 7.0 micrograms/ml for those of MSSA. These results suggest that plaunotol may be useful in the prevention of infection by MRSA and in skin care for patients with atopic dermatitis.

Anti-Bacterial Agents↗

PubMed1998

Technetium-99m-tetrofosmin, technetium-99m-MIBI and thallium-201 uptake in rat myocardial cells.

UNLABELLED: The mechanisms of uptake and intracellular distribution of 99mTc-tetrofosmin, 99mTc-MIBI and 201TI and the behaviors of 99mTc-tetrofosmin and 99mTc-MIBI in relation to Na+ were studied with primary cultures of myocardial cells. METHODS: Both the uptake and the washout of the tracers were sequentially measured. The cells were treated with ouabain, bumetanide, tetrodotoxin, dimethyl amiloride (DMA), nigericin and carbonyl cyanide m-chlorophenylhydrazone (CCCP) to observe the effects of the uptake and intracellular distribution of the traders. Cells equilibrated in buffers with or without Na+ were treated with monensin and DMA to evaluate the effect of Na+ on the accumulation of the tracers. RESULTS: Despite the similarities in uptake kinetics, there was a higher level of retention of 99mTc-tetrofosmin inside the cells. Ouabain, bumetanide and tetrodotoxin did not show any inhibitory effect on the uptake of 99mTc-tetrofosmin and 99mTc-MIBI, whereas they produced various degrees of inhibition of 201TI uptake. DMA produced approximately 35% inhibition of 99mTc-tetrofosmin uptake and 50% inhibition of 99mTc-MIBI uptake. Nigericin increased the uptake of 99mTc-MIBI by the cells. The addition of CCCP produced the release of 38% of the accumulated 99mTc-tetrofosmin and 52%-70% of the accumulated 99mTc-MIBI, indicating that these percentages of accumulation were related to mitochondrial uptake. Neither Na+-free buffer nor monensin had any significant effect on 99mTc-tetrofosmin accumulation, but they both caused increased accumulation of 99mTc-MIBI. CONCLUSION: The uptake of both 99mTc-tetrofosmin and 99mTc-MIBI through the cell membrane is partly related to the Na+/H+ antiporter system. Only part of the accumulated 99mTc-tetrofosmin inside the cells enters into mitochondria; most of the accumulated 99mc-MIBI is related to mitochondrial uptake. This uptake may be related to Na+.

Amiloride↗

PubMed1998

[Infective endocarditis associated with ruptured aneurysm of Valsalva: aortic valve replacement after reconstruction of left ventricular outflow tract].

Infective endocarditis associated with ruptured aneurysm of Valsalva disrupted the vicinity of aortic annulus (Valsalva, valve, left ventricular outflow tract). This condition did not accept insertion of prosthetic valve at normal position. Insertion of St. Jude valve was performed after the reconstruction of outflow tract with a xenopericardial patch. Proportionate sutures for the right cusp part was taken through the infundibular muscle at the right ventricular side, not in the pericardial patch. The bileaflet valve functioned properly in spite of the oblique insertion.

Adult↗

PubMed1998

[Placement of self-expanding metallic stents in the stenotic trachea and bronchus under the support of gas exchange by extracorporeal lung assist (ECLA)].

Three self-expanding metallic stents (MS) were placed in a patient with severe dyspnea due to tracheo-bronchial stenosis caused by a large metastatic malignant tumor. To ensure adequate gas exchange, we used ECLA during surgery. After ECLA was started with V-V bypass (blood flow 1.3 l.min-1, 100% O2 flow 10 l.min-1), the patient was administered droperidol and fentanyl, and orotracheally intubated with an endotracheal tube (7.0 mm ID) using a bronchofiberscope. Anesthesia was maintained with midazolam, but no neuromuscular blocking agent was used. The pulmonary ventilation was withheld 3 times during each period of 5-10 min for MS placement through the endotracheal tube. The patient was ventilated for a few min between each procedure. Values of arterial blood gas were maintained within physiological ranges throughout the surgery. ECLA was a useful means of ensuring adequate gas exchange in perioperative patients with difficult airway.

Adolescent↗

PubMed1998

[An experience with peeling technique with curettage of open mitral commissurotomy].

Ideally, the mitral valve is a soft, thin and flexible tissue. In severe rheumatic mitral stenosis, however, its motion is restricted due to the adhesion of fibrous tissues and calcium. Open mitral commissurotomy was not effective in successfully restoring it to normal condition. By using a peeling technique with curettage during open mitral commissurotomy, the calcium and fibrous tissues are sufficiently removed. This method is effective in improving the flexibility of the anterior leaflet of the restricted mitral valve.

Cardiac Surgical Procedures↗