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Biomedical subjects

A Takada

Publications and source records attributed to A Takada.

At least 127 records · Page 7Linked to original sources
PubMed1997

Differences in sialic acid-galactose linkages in the chicken egg amnion and allantois influence human influenza virus receptor specificity and variant selection.

Human influenza viruses are more efficiently isolated by inoculating patient samples into the amniotic rather than the allantoic cavity of embryonated chicken eggs. This type of cultivation selects virus variants with mutations around the hemagglutinin (HA) receptor binding site. To understand the molecular basis of these phenomena, we investigated the abundances of sialic acid (SA) linked to galactose (Gal) by the alpha-2,3 linkage (SA alpha2,3Gal) and SA alpha2,6Gal in egg amniotic and allantoic cells and in Madin-Darby canine kidney (MDCK) cells. Using SA-Gal linkage-specific lectins (Maackia amurensis agglutinin specific for SA alpha2,6Gal and Sambucus nigra agglutinin specific for SA alpha2,3Gal), we found SA alpha2,3Gal in both allantoic and amniotic cells and SA alpha2,6Gal in only the amniotic cells. MDCK cells contained both linkages. To investigate how this difference in abundances of SA alpha2,3Gal and SA alpha2,6Gal in allantoic and amniotic cells affects the appearance of host cell variants in eggs, we determined the receptor specificities and HA amino acid sequences of two different patient viruses which were isolated and passaged in the amnion or in the allantois and which were compared with MDCK cell-grown viruses. We found that the viruses maintained high SA alpha2,6Gal specificities when grown in MDCK cells or following up to two amniotic passages; however, further passages in either the amnion or allantois resulted in the acquisition of, or a complete shift to, SA alpha2,3Gal specificity, depending on the virus strain. This change in receptor specificity was accompanied by the appearance of variants in the population with Leu-to-Gln mutations at position 226 in their HA. These findings suggest that lack of SA alpha2,6Gal linkages in the allantois of chicken eggs is a selective pressure for the appearance of host cell variants with altered receptor specificities and amino acid changes at position 226.

Allantois↗
PubMed1997

Tissue factor expression and fibrin deposition in the lungs of patients with idiopathic pulmonary fibrosis and systemic sclerosis.

Although abnormalities of alveolar fibrin turnover have been reported to play a role in the development of idiopathic pulmonary fibrosis (IPF), the pathophysiological relevance remains unclear. We therefore investigated the localization of tissue factor (TF) and fibrin deposition in patients with IPF using immunohistochemistry and compared the results with those from patients who had interstitial pneumonia associated with systemic sclerosis (IP-SSc) and idiopathic bronchiolitis obliterans with organizing pneumonia (BOOP). Expression of TF-mRNA was also assessed, using in situ hybridization with a digoxigenin-labeled cRNA probe. In patients with IPF, IP-SSc, and idiopathic BOOP, the TF antigen was positively stained in type II pneumocytes and in some alveolar macrophages. The fibrin antigen was stained in the type II pneumocytes and the adjacent area. Tissue factor-mRNA was expressed in the type II pneumocytes and in some alveolar macrophages. Neither TF antigens nor TF-mRNA were detected in the normal lung. These results indicate that type II pneumocytes are a major source of TF, suggesting that TF production in these cells is closely related to fibrin deposition in the lungs of people with these diseases.

Base Sequence↗
PubMed1997

Fibrinolytic parameters as an admission prognostic marker of head injury in patients who talk and deteriorate.

Because it has been difficult to predict the outcome of patients with head injury in the early period after admission, a clinical study was undertaken to evaluate if the fibrinolytic parameters could be reliable indicators of outcome. Seventy patients presenting with head injury without obvious trauma in other regions were studied, and plasma levels of alpha2-plasmin inhibitor-plasmin complex (PIC) and D-dimer on admission (within 2 hours postinjury) were assessed. Plasma levels of both PIC and D-dimer were elevated and correlated well to patient outcomes. When plasma PIC levels were higher than 15 microg/ml or D-dimer levels were higher than 5 microg/ml, 92% of patients died regardless of their consciousness level on admission, whereas all patients made good recoveries when their PIC levels were less than 2 microg/ml or D-dimer levels were less than 1 microg/ml. Therefore, plasma levels of both PIC and D-dimer on admission were revealed to be reliable prognostic markers of head injury. Using these markers, patients with poor outcomes (progressive brain injury), such as "talk and deteriorate" types, could be readily identified on admission.

Adolescent↗
PubMed1997

Glass transition temperatures of dental porcelains determined by DSC measurement.

The differential scanning calorimetry (DSC) curves for three commercial dentin and incisal porcelains fused-to metal were measured using high-temperature DSC. The glass transition temperatures (Tg) were determined from the DSC curves at heating rates of 7-20 degrees C/min, and the activation energy was derived from an Arrhenius plot of negative reciprocal Tg vs. logarithm of heating rate. The Tg of the dental porcelains depended on the content of aluminum oxide, whereas the activation energy depended on the content of sodium oxide. The ultra-low fusing type porcelains had a low activation energy due to the higher content of sodium oxide than the other porcelains.

Aluminum Oxide↗
PubMed1997

[Pharmacognostical studies on the stem and leaf of Chinese Alyxia].

About the stem and leaf of Chinese alyxia, pharmacognostical studies on the character, microscopical and physichemical aspects are made, The results are certifed that the methods of determination on the character and microscopical may be adopt for stem and leaf Chinese alyxia. There are a rich amino acids and trace elements. It provide scientific basis for its comprehensive development and utilization.

Amino Acids↗
PubMed1997

[Trial of radiation and cisplatin, carboplatin combination chemotherapy for advanced cancer (W-platinum chemoradiotherapy].

Cisplatin was reported to be an effective radiation sensitizing agent. The effect was also reported to depend on dose intensity. But the incidence of complication was demonstrated in the relationship with the dose escalation curve of anti-cancer agent. The major side effect of CDDP was occasionally serious, as in renal toxicity or bone marrow suppression. W-Platinum is the trial of concurrent chemoradiotherapy. Cisplatin and its derivative, Carboplatin, were selected as effective radiation sensitizing agents and to obtain high-dose intensity and additive cytotoxicities by interaction between the two drugs. Concomitant administration of two platinum anti-cancer agents has the advantage of reduction of side effects compared with administration of single anti-cancer agents to the same degree. The first case was a recurrence of epipharyngeal cancer after 3 courses of chemotherapy, including CDDP or CBDCA. This case was suspected to be cancer-resistant to CDDP. The second case was post-operative residual lung cancer. The pre-operative diagnosis was stage III A. A poor prognosis was expected. This case was disease-free and alive for 1 year after W-Platinum administration. The most frequent complication was bone marrow suppression. Patients were rescued from bone marrow suppression with administration of G-CSF. Renal toxicity could be suppressed with sufficient hydration.

Adenocarcinoma↗
PubMed1997

Suicide by self-stabbing in the city of Tokyo--a review of accumulated data from 1976 to 1995.

Accumulated data of suicide by self-stabbing in the city of Tokyo (population: approx. 8.1 million. 1994) between 1976 and 1995 was reviewed. The overall numbers of suicides for each year were similar (min.: 1178, max.: 1620, 1346.9 on average), while the annual number of unusual death cases increased gradually (5399 in 1976 to 9226 in 1995). The annual number of suicides by self-stabbing fluctuated irregularly, but was generally low (2.3-4.7%) among modes of suicide. A significant difference was observed between the sex ratio in suicidal self-stabbing and that for all suicide; the male/female ratio is higher in suicidal self-stabbing than in suicides overall. The majority of fatally wounded body sites were in the neck, chest, abdomen, wrists and forearms. Marked differences according to sex were observed in terms of the implements employed for self-stabbing; craft knives, swords and recreational knives, fragments of glass, carpenter's tools and surgical knives were used almost exclusively by men, while more than 80% of women used kitchen knives or razors. No influence of psychiatric history on suicide by self-stabbing was proved.

Adolescent↗
PubMed1996

The effect of a 5HT2 receptor antagonist sarpogrelate (MCI-9042) treatment on platelet function in Buerger's disease.

The effect of a new, specific 5-HT2 receptor antagonist sarpogrelate (MCI-9042) treatment on platelet function and serotonin levels in both plasma and whole blood in Buerger's disease, was assessed in a pilot study. We investigated 10 patients suffering from Buerger's disease. Sarpogrelate in a dose of 3 x 100 mg a day was given p.o. for a period of 8 weeks. It was well tolerated and no major side effects were noted. It was judged to be effective in some patients as assessed by its effect on both subjective complaints and objective evaluation of ankle pressure index (API). Sarpogrelate induced a significant decrease in plasma serotonin (5-HT) concentration starting after the 4th week which lasted through to the 8th week of the study, whereas plasma tryptophan concentration increased significantly after 2 and 4 weeks. There were no changes in plasma 5-HIAA concentration. On the other hand whole blood 5-HT concentration increased significantly after 2 weeks, and there was also a tendency to increase in whole blood tryptophan concentration (p = 0.052). Platelet aggregation induced by ADP and collagen did not show any statistically significant changes. Surprisingly, platelet aggregation induced by serotonin increased significantly after 2 weeks and even more so after 4 weeks of treatment, and then it returned to baseline values after 8 weeks. There was no effect on platelet count, APTT, TT and fibrinogen concentration.

Administration, Oral↗
PubMed1996

The inhibition of human factor Xa by plasminogen activator inhibitor type 1 in the presence of calcium ion, and its enhancement by heparin and vitronectin.

Plasminogen activator inhibitor type 1 (PAI-1), a member of serine proteinase inhibitor superfamily, is known to inhibit thrombin in the presence of either heparin or vitronectin. We analyzed possible inhibitory activity of PAI-1 on human factor Xa. PAI-1 inhibited factor Xa in the presence of calcium ion (Ca2+), whereas no inhibition was observed in the absence of Ca2+. Half maximal enhancement by Ca2+ was obtained at 0.8 mM. An equimolar complex formation between factor Xa and PAI-1 in the presence of Ca2+ was observed by SDS polyacrylamide gel electrophoresis. Both unfractionated heparin and vitronectin enhanced the inhibition only in the presence of Ca2+. Apparent second-order rate constant (ki) for the inhibition of factor Xa by PAI-1 at 5 mM Ca2+ was 1.6 x 10(4) M-1 s-1, and was enhanced 3-fold by 2 u/ml of heparin (4.6 x 10(4) M-1 s-1) and 10-fold by 100 nM vitronectin (1.6 x 10(5) M-1 s-1), respectively. The interaction between Ca(2+)-bound factor Xa and PAI-1 could be important from the view of PAI-1 neutralization and enhancement of fibrinolysis.

Calcium↗
PubMed1996

Genetic organization and diversity of the 3' noncoding region of the hepatitis C virus genome.

The 3' noncoding region (3' NCR) of the hepatitis C virus (HCV) genome contained in viral particles was analyzed by an RNA linker ligation followed by reverse transcription-polymerase chain reaction. Sequence analysis of the amplified fragment from four strains, including different genotypes 1b, 2b, 3a, and 3b indicated that the 3' NCR is composed of between 200 and 235 nts. The sequence of the 3' NCR consists of a type-specific region (immediately following the termination codon), a poly(U) stretch, a C(U)n-repeat, and highly conserved region termed the core element. The poly(U) stretch and C(U)n-repeat regions varied in length and in sequence among different genotypes. Core elements having putative secondary structure consisted of 98 or 100 nts and were highly conserved in all genotypes. Most of the nt changes found in different genotypes did not affect the secondary structure of the core elements, suggesting that this region may play an important role in replication, stabilization of the HCV RNA, and/or packaging of the genome. Most of the HCV-1b strains carried two U residues at the 3' end of the core element, while the minor HCV-1b strains had no U residues, demonstrating that there are two variants in type 1b strains. Amplification of the core element using linker-primed cDNA was comparable with that using the 3' proximal core element-primed cDNA, indicating that the 3' end of HCV genome was terminated by an OH group.

Base Sequence↗
PubMed1996

The effect of tacrolimus (FK506) and cyclosporin A (CyA) on peripheral serotonergic mechanisms in uremic rats.

The aim of this study was to investigate the mechanism of hypertension and thromboembolic events induced by cyclosporin (CyA) and tacrolimus (FK506) in respect to their action on the serotonergic blood system. The study was carried out on healthy rats and those with experimental chronic renal failure. CyA injected into healthy and uremic rats caused an increase in serotonin (5-HT) concentration levels in whole blood and platelets. Concomitantly a rise in systolic blood pressure was observed. Platelet aggregation values were significantly higher in uremic rats given CyA. FK506 had no influence on 5-HT blood content, blood pressure or platelet aggregation values. It is concluded that 5-HT may play a role in the development of hypertension and thrombotic events caused by CyA. Furthermore, lower incidence of these complications during FK506 treatment could be the result of this drug's limited effect on the serotonergic blood system.

Animals↗
PubMed1996

The in vitro effects of chylomicron remnant and very low density lipoprotein remnant on platelet aggregation in blood obtained from healthy persons.

We investigated the in vitro influence of chylomicron (CM) remnant and very low density lipoprotein (VLDL) remnant on platelet aggregation in healthy persons. The separation of CM and VLDL remnants from serum was performed using an immunoaffinity gel mixture containing anti apo B-100 and anti apo A-1 antibodies coupled to Sepharose 4B. The preincubation with CM and VLDL remnants significantly enhanced the platelet aggregation in whole blood and in platelet rich plasma (PRP) induced by collagen. This effect was observed in whole blood with the addition of VLDL remnant at the concentration of 5 mu g/ml, and in PRP with the addition of CM remnant at the concentration of 1 and 5 mu g/ml, and with the addition of VLDL remnant at the concentration of 5 and 10 mu g/ml. These results may indicate that increase in remnant lipoproteins may be a part of the reasons for atherosclerotic and thrombotic complications.

Antithrombins↗
PubMed1996

Detection of a unique gamma-glutamyl transpeptidase messenger RNA species closely related to the development of hepatocellular carcinoma in humans: a new candidate for early diagnosis of hepatocellular carcinoma.

Many studies concerning gamma-glutamyl transpeptidase (GGTP) in hepatocellular carcinoma (HCC) have suggested that changes in hepatic GGTP expression may be closely related to the development of HCC. However, its mechanisms are not well known, and genomic analysis of the specific GGTP to HCC is also lacking. Recently, the human GGTP complementary DNA (cDNA) sequences from fetal liver, placenta, and HepG2 cells have been published. In the present study, we sought to clarify the distribution of the GGTP messenger RNA (mRNA) molecular species in human liver and determine whether alterations in GGTP mRNA expression occur upon the development of HCC. The specific primer sets for reverse-transcription polymerase chain reaction (PCR) corresponding to the 5'-noncoding human GGTP mRNA of fetal liver (type A), HepG2 cells (type B), and placenta (type C) were prepared. Oligonucleotide probes specific for each type of mRNA were also synthesized. Liver tissues were obtained from patients with or without HCC, and total RNA was extracted. Total RNA was also extracted from various organs obtained from one male patient upon autopsy. Types of GGTP mRNAs were analyzed using type-specific primer sets and oligonucleotide probes. The types of GGTP mRNA varied in different organs. In normal liver and diseased liver without HCC, the main type of GGTP mRNA was type A. The expression was monogenic in most cases but was polygenic in some cases. In the polygenic cases, type C was common, but type B was found occasionally. On the other hand, type B was predominant in cancerous tissues with HCC. In noncancerous tissues of livers with HCC, the main types were types A and B. The prevalence of type B was significantly higher in both cancerous and noncancerous tissues of livers with HCC than in livers without HCC. The prevalence of type A in cancerous tissue, but not in noncancerous tissue, was significantly lower than in livers without HCC. These results strongly suggested that the GGTP mRNA expression in human liver may shift from type A to type B during the development of HCC. The high prevalence of type B in noncancerous tissues suggested that the shift of the GGTP mRNA may occur from the preneoplastic stage of hepatocytes.

Base Sequence↗
PubMed1996

Serum type IV collagen in various liver diseases in comparison with serum 7S collagen, laminin, and type III procollagen peptide.

The clinical significance of the immunoreactive triple helical domain of type IV collagen in serum was evaluated in 73 healthy controls and 161 patients with various biopsy-proven liver diseases. Although serum levels of type III procollagen peptide were increased in all liver diseases, those of type IV collagen, 7S collagen, and laminin were principally increased in chronic liver diseases associated with hepatic fibrogenesis/fibrosis. In both non-alcoholic and alcoholic liver diseases, 7S collagen was increased in serum, while type IV collagen and laminin in serum were particularly increased in alcoholic liver diseases and in hepatocellular carcinoma, in which latter the sensitivity was greater for type IV collagen than for laminin. Gel filtration analysis in Sephacryl S-400 revealed type IV collagen in serum to be a single molecular form with a molecular weight that correspond to type IV collagen, whereas 7S collagen was recognized as several heterogeneous macromolecules. These findings indicate that serum type IV collagen is derived from the type IV protocollagen pool, and is a sensitive marker for the fibrogenetic process in hepatic basement membranes.

Adult↗
PubMed1996

Changes in serotonergic measures in whole blood and various brain regions of rats administered with the 5-HT1A agonist tandospirone and/or exposed to electric foot-shock.

We studied the effects of foot-shock on tryptophan, serotonin [5-hydroxytryptamine (5-HT)], and its metabolite, 5-hydroxyindole acetic acid (5-HIAA) in whole blood and various brain regions of rats pretreated with tandospirone, a novel 5-HT1A receptor agonist. The administration of tandospirone did not result in changes in serotonergic measures, but stress or stress plus the administration of tandospirone resulted in an increase in blood levels of tryptophan, 5-HT, and 5-HIAA. In animals given stress, tryptophan levels rose in every part of the brain, and in animals given stress and tandospirone, tryptophan levels increased in all the brain regions except the medulla. The administration of tandospirone alone did not give rise to changes in tryptophan levels in any part of the brain. The administration of tandospirone resulted in an increase in 5-HT levles in all brain regions except the cerebellum. In rats given stress and tandospirone, 5-HT levels increased in the hypothalamus, midbrain, and cortex relative to controls. In every part of the brain, the administration of tandospirone resulted in a decrease in the turnover rate of serotonin (5-HIAA/5-HT). In the presence of stress, the administration of tandospirone resulted in a decrease in the turnover rate of serotonin in hypothalamus, hippocampus, and midbrain compared with controls and stress alone. These results suggest that tandospirone may stimulate presynaptic receptors in the midbrain and inhibit the activity of monoamine oxidase, resulting in an increase in 5-HT levels in the serotonergic nerve terminals.

Animals↗
PubMed1996

Protective immune response of chickens against Newcastle disease, induced by the intranasal vaccination with inactivated virus.

Intranasal vaccination of chickens with inactivated Newcastle disease virus (NDV) induced both local and systemic antibody responses, resulting in protection against intranasal challenge with a lethal dose of a virulent NDV strain. The immune response was enhanced by the use of cholera toxin B subunit (CTB) as an adjuvant and only small amounts of the challenge virus were recovered from the birds vaccinated together with CTB. On the other hand, subcutaneous vaccination with the same antigen induced only a serum antibody response in chickens, allowing the challenge virus to replicate in the sinus. The present results indicate that secretory antibodies induced on the respiratory mucosal surface by intranasal vaccination with inactivated NDV protected chickens from lethal infection by inhibiting virus replication at the portal of entry for the virus.

Adjuvants, Immunologic↗