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Biomedical subjects

M Fujiwara

Publications and source records attributed to M Fujiwara.

At least 163 records · Page 9Linked to original sources
PubMed1999

Decreased interferon-gamma (IFN-gamma)-producing T cells in patients with acute Kawasaki disease.

Kawasaki disease (KD) is an acute febrile illness of early childhood, in which the activation of monocytes/macrophages plays a central role in the development of vasculitis during the acute stage of disease. In this study we investigated peripheral blood T cells of 10 patients with KD, focusing on the Th1 and Th2 imbalance, using intracellular cytokine staining and analysis of the cytokine-producing T cells by flow cytometry. We observed a decrease in the numbers of IFN-gamma-producing, but not IL-4-producing, CD3+ T cells, during the acute stage. Our results suggest that there is an imbalance of Th1 and Th2 subsets during the acute stage of KD.

CD3 Complex↗
PubMed1999

An immunohistochemical study of the mesenchymal and epithelial components of pulmonary chondromatous hamartomas.

Twenty-five cases of solitary pulmonary chondromatous hamartomas (PCH) were examined by immunohistochemistry to evaluate the mesenchymal and epithelial components. PCH composed of predominantly mature cartilage were designated as C type, those predominantly composed of fibromyxoid tissue as FM type, and those predominantly composed of adipose tissue as A type. FM type PCH revealed various amounts of cartilage in various developmental stages, adipose tissue and fibromyxoid tissue, compared with a uniform pattern of cartilage tissue in C type. The cells of transitional form between spindle cells, stellate cells and chondrocytes were present in FM type. Epithelial components in PCH were bronchial, bronchiolar and cuboidal cells, mostly at the periphery of PCH. S-100 protein consistently stained chondrocytes, stellate and spindle cells in the fibromyxoid tissue of solitary PCH. Fibroblast growth factor was immunolocalized to chondrocytes, spindle and stellate cells in the fibromyxoid tissue. The collagen type was associated with differentiation from primitive mesenchymal cells to chondrocytes (i. e. type I and III collagen appeared in fibromyxoid matrix and type II collagen in the cartilaginous matrix). Fibronectin coordinately appeared with type I and III collagens. The proliferating cell nuclear antigen labeling index of epithelial cells was comparable to those of neoplastic mesenchymal cells, but it was not significantly different between C type and FM type PCH. The primitive mesenchymal cells in the bronchial walls of the control premature neonates were also observed. This immunohistochemical study showed that the progenitor mesenchymal cells in the bronchial and bronchiolar walls may differentiate along chondrocytes, lipocytes, and smooth muscle cells in PCH and that epithelial proliferation is reactive and closely associated with neoplastic proliferation of the mesenchymal component.

Adult↗
PubMed1999

Plastidic RNA polymerase sigma factors in Arabidopsis.

In plant cells, plastid DNA is transcribed by at least two types of RNA polymerase, plastid-encoded RNA polymerase (PEP) and nuclear-encoded RNA polymerase (NEP). PEP is homologous to eubacterial transcription machinery, but its regulatory subunit, sigma (sigma) factor, is not encoded on the plastid DNA. We previously cloned the three nuclear-encoded sigma factor genes from Arabidopsis thaliana and designated them as sigA, sigB, and sigC. By means of RFLP mapping, sigA and sigB were mapped on chromosome I and sigC on the chromosome III. Based on comparison of the genomic structure of the three sig genes, intron sites in the 3' half of the genes were shown to be identical between sigB and sigC but divergent in sigA, consistent with the phylogenetic relevance of the three gene products. A transient expression assay of GFP fusions in Arabidopsis protoplasts showed that the N-termini of all three sig gene products functioned as chloroplast-targeting signals. We also constructed transgenic Arabidopsis lines harboring the sigA-promoter or the sigB-promoter uidA fusion. Both the sigA- and sigB-promoters were similarly activated at cotyledons, hypocotyls, rosette leaves, cauline leaves, sepals, and siliques but not at roots, seeds, or other flower organs. In addition, the two promoters were repeatedly activated in young seedlings under continuous light, possibly in an oscillated fashion.

Amino Acid Sequence↗
PubMed1999

A simple, reliable method of assessing exercise capacity in patients with chronic heart failure.

OBJECTIVE: The accurate determination of limitations in physical activity is important in evaluating patients with heart failure and in assessing the efficacy of treatment. However, the conventional measures used to evaluate hemodynamics, functional class, and exercise capacity all have limitations. Our objective was to develop a simple method (The Master-Borg test) for evaluating the physical activity of patients with chronic heart failure using self-evaluation of the sensation of dyspnea at a constant workload. METHODS: Patients with NYHA class I (N = 20), class II (N = 20), and class III (N = 20) chronic heart failure performed a symptom-limited treadmill exercise test to determine peak VO2 and anaerobic threshold (AT). Patients subsequently performed Master's two-step test for 90 s and maximal dyspnea was self-rated using the visual analog Borg scale (the Master-Borg test). RESULTS: The mean workload in the Master-Borg test was 15.2+/-1.6 mL x min(-1) x kg(-1). A significant correlation was found between the Master-Borg score and peak VO2 (r = 0.87) or AT (r = 0.84). The reproducibility of the Master-Borg tests was represented by a correlation coefficient of 0.93. CONCLUSION: Although simple and inexpensive, the Master-Borg test accurately represents ordinary activity levels, relates the sensation of dyspnea to peak exercise tolerance, and can be completed by most patients with heart failure. Master-Borg scores correlated with peak VO2 and AT, and can differentiate among NYHA classes I, II, and III. The Master-Borg test appears to be clinically useful for evaluating the value of physical activity and exercise capacity of patients with chronic heart failure.

Aged↗
PubMed1999

Protein expression of cell cycle regulator, p27Kip1, correlates with histopathological grade of non-Hodgkin's lymphoma.

The protein p27Kip1 is one of the cyclin-dependent kinase inhibitors that are known to play important roles in the regulation of cell-cycle progression. Low levels of p27 expression in malignant cells are associated with poor prognosis in patients with breast, lung, colorectal and gastric cancers. To determine the relation of cyclin-dependent kinase inhibitors to histopathological grades of B-cell non-Hodgkin's lymphomas, the expression of p27, cyclin D1 and cyclin E in lymph node tissues was investigated in 56 patients with B-cell non-Hodgkin's lymphomas by western blotting and immunohistochemical techniques. High levels of p27 expression were observed in most lymph node tissue samples (93%) obtained from patients with low grade B-cell non-Hodgkin's lymphomas, while expression was low in lymph node tissue taken from all patients with intermediate and high grade B-cell non-Hodgkin's lymphomas. The difference in p27 expression in lymphoma tissues was significant among the different histopathological grades of B-cell non-Hodgkin's lymphomas (P<0.01). The analysis of the survival time of patients showed that the reduction of p27 expression correlated with poor prognosis. Cyclin D1, showed a high level of expression in mantle cell lymphomas and high grade B-cell non-Hodgkin's lymphomas. Cyclin E showed limited expression in 18 of 31 lymphoma tissues. Both cyclin D1 and E protein expression were not significantly different among the grades of B-cell non-Hodgkin's lymphomas. These results demonstrate that the level of p27 expression in lymphoma tissue is an important parameter in the classification of B-cell non-Hodgkin's lymphomas and in the prediction of prognosis.

Blotting, Western↗
PubMed1999

Proliferation of intrahyphal hyphae caused by disruption of csmA, which encodes a class V chitin synthase with a myosin motor-like domain in Aspergillus nidulans.

We have found that the Aspergillus nidulans csmA gene encodes a novel protein which consists of an N-terminal myosin motor-like domain and a C-terminal chitin synthase domain (M. Fujiwara, H. Horiuchi, A. Ohta, and M. Takagi, Biochem. Biophys. Res. Commun. 236:75-78, 1997). To clarify the roles of csmA in fungal morphogenesis, we constructed csmA null mutants. The growth rate of the mutant colonies was almost the same as that of the wild-type strain, but hyphal growth was severely inhibited when a chitin-binding reagent, Calcofluor white or Congo red, was added to the medium. Moreover, morphological abnormalities in tip growth and septum formation were identified microscopically. Proliferation of intracellular new hyphae, called intrahyphal hyphae, which behaved as intrinsic hyphae, was the most striking phenotypic feature among them. These phenotypes were not suppressed when the only chitin synthase domain of csmA was expressed under the control of the alcA promoter, whereas they were suppressed when the intact form of csmA was expressed. Therefore, it was concluded that the product of csmA (CsmA) has important roles in polarized cell wall synthesis and maintenance of cell wall integrity and that the myosin motor-like domain is indispensable for these functions.

Aspergillus niger↗
PubMed1999

Human follicular dendritic cells remain uninfected and capture human immunodeficiency virus type 1 through CD54-CD11a interaction.

It has been reported that human immunodeficiency virus type 1 (HIV-1) bound to follicular dendritic cells (FDCs) remains highly infectious to CD4(+) T cells even when it forms immune complexes with neutralizing antibody (HIV-1/IC). To elucidate the role of FDCs in HIV-1 transmission to CD4(+) T cells in lymph nodes, we have isolated and purified FDCs from human tonsils and examined whether the HIV-1/IC trapped on their surface is infectious to CD4(+) T cells. To our surprise, not the HIV-1/IC but the antibody-free HIV-1 on FDCs could be transmitted to CD4(+) T cells. Furthermore, in contrast to previous studies showing that FDCs are productively infected with HIV-1, the present study clearly demonstrated that FDCs were not the target cells for HIV-1 infection. FDCs could capture the viral particles on their surface; however, the binding of HIV-1 to FDCs was strongly inhibited by the presence of anti-CD54 (ICAM-1) monoclonal antibody (MAb) and anti-CD11a (LFA-1) MAb, suggesting that the adhesion molecules play an important role in the interaction between HIV-1 and FDCs.

CD4-Positive T-Lymphocytes↗
PubMed1999

Inhibition of human immunodeficiency virus replication by RD6-Y664, a novel benzylhydroxylamine derivative.

We have examined novel benzylhydroxylamine derivatives for their inhibitory effects on the replication of human immunodeficiency virus (HIV) in cell cultures. Among the series, O-(2-chloro-6-fluorobenzyl)hydroxylamine (RD6-Y664) was found to be the most potent inhibitor of HIV-1. The EC50 for HIV-1 strain IIIB was 1.6 micrograms/ml with a selectivity index greater than 38 in MT-4 cells. It also inhibited the replication of other HIV strains including a non-nucleoside reverse transcriptase (RT) inhibitor-resistant mutant, a nucleoside RT inhibitor-resistant mutant and HIV-2, in acutely infected cells. However, the compound did not affect HIV-1 production in chronically infected cells. A time-of-addition experiment and detection of proviral DNA synthesis suggested that RD6-Y664 targeted an early step of the viral replication cycle, presumably a process prior to reverse transcription. In fact, an assay for HIV-1 RT revealed that the compound did not suppress enzyme activity. Furthermore, RD6-Y664 did not show any inhibition of gp120-CD4 interaction, or binding of anti-CXCR4 antibody to CXCR4.

Anti-HIV Agents↗
PubMed1999

Characterization of human immunodeficiency virus type 1 strains resistant to the non-nucleoside reverse transcriptase inhibitor RD4-2217.

The non-nucleoside reverse transcriptase (RT) inhibitor RD4-2217 is a thiadiazole derivative that has proved to be a highly potent and selective inhibitor of human immunodeficiency virus type 1 (HIV-1) replication in vitro. In this study we examined genotypic and phenotypic characteristics of RD4-2217-resistant mutants that have been obtained by serial passage of HIV-1 in MT-4 cells in the presence of increasing concentrations (0.05, 0.25, 1 and 10 microM) of the compound. The strains obtained, III(B/2217RE/0.05) and III(B/2217RE/0.25,) were two- and 15-fold resistant to RD4-2217, respectively, whereas III(B/2217RE/1) and III(B/2217RE/10) displayed 161- and >238-fold resistance, respectively. Both III(B/2217RE/1) and III(B/2217RE/10) had two amino acid substitutions, V1891 and T2401, in the RT. Furthermore, RD4-2217 did not inhibit the replication of an HIV-1 molecular clone, which had the same mutation, at concentrations up to 10 microM, indicating that the V1891 plus T2401 mutation confers high-level resistance to RD4-2217. Interestingly, the replicability of III(B2217RE/1) and III(B/2217RE/10) appeared to be lower than that of wildtype III(B) in MT-4 cells, suggesting that the V1891 plus T2401 mutation may impair the enzymatic activity of HIV-1 RT.

Anti-HIV Agents↗
PubMed1999

A novel WD40 protein, CHE-2, acts cell-autonomously in the formation of C. elegans sensory cilia.

To elucidate the mechanism of sensory cilium formation, we analyzed mutants in the Caenorhabditis elegans che-2 gene. These mutants have extremely short cilia with an abnormal posterior projection, and show defects in behaviors that are mediated by ciliated sensory neurons. The che-2 gene encodes a new member of the WD40 protein family, suggesting that it acts in protein-protein interaction. Analysis of mutation sites showed that both the amino-terminal WD40 repeats and the carboxyl-terminal non-WD40 domain are necessary for the CHE-2 function. CHE-2-tagged green fluorescent protein is localized at the cilia of almost all the ciliated sensory neurons. Expression of che-2 in a subset of sensory neurons of a che-2 mutant by using a heterologous promoter resulted in restoration of the functions and cilium morphology of only the che-2-expressing neurons. Thus, che-2 acts cell-autonomously. This technique can be used in the future for determining the function of each type of che-2-expressing sensory neuron. Using green fluorescent protein, we found that the extension of cilia in wild-type animals took place at the late embryonic stage, whereas the cilia of che-2 mutant animals remained always short during development. Hence, the abnormal posterior projection is due to the inability of cilia to extend, rather than degeneration of cilia once correctly formed. Expression of che-2 in a che-2 mutant under a heat shock promoter showed that the extension of cilia, surprisingly, can occur even at the adult stage, and that such cilia can function apparently normally in behavior.

Amino Acid Sequence↗
PubMed1999

[Treatment of solid tumor by a direct electric current].

This is a case report of a 37-year-old Japanese married female with laryngeal sarcoma, treated by direct electric current so as to obtain remission for more than 4 years without signs of recurrence. Due to her hoarseness and laryngeal numb feeling she underwent a laryngeal examination including a biopsy, resulting in a diagnosis of sarcoma. She refused a total laryngectomy and was given Cobalt treatment of 40 Grey. In the following several months, no improvement was observed, objectively or subjectively. In Nagoya University Hospital the patient then received direct electric current therapy of 36 Coulombs through two platinum electrodes inserted into the tumor under a CT guide, pericutaneously. Two months later, as the hoarseness remained in spite of some improvement, she underwent another session of direct electric current therapy of 14.4 Coulombs through the platinum electrodes by bronchoscope-guided direct insertion. Her hoarseness soon disappeared thereafter and there was a regression of the tumor in 6 months. She did well thereafter without any signs of recurrence for 4 years. Clinical treatment of solid tumors with electric treatment with direct electric current has been done in more than 8,000 cases with CR in 25% of all cases and PR in 50%. Its mechanism, however, remains unclear. In our experimental animal studies, apoptosis was observed. It is considered that this electric therapy using direct electric current will be recognized as one method to treat solid tumors.

Adult↗
PubMed1999

Effects of subthreshold transcranial magnetic stimulation on choice reaction time and correlation with motor cortical activation.

To study the effect of subthreshold transcranial magnetic stimulation (TMS), we measured choice reaction time (RT), with or without TMS, in 7 healthy participants. TMS over the hand motor area was randomly delivered at variable delays after the imperative signal, while participants performed right or left abduction of the thumb. Lateralized movement-related potentials (MRPs) were recorded in a separate session to link the TMS effect with the motor cortical circuitry. For the right hand, the coexistence of a motor specific and non-specific effects of TMS was clearly evidenced, by the RT shortening at delays of 0 and 150 ms. The response dependency of the specific TMS effect was also demonstrated through the response-locked analysis, showing a maximal shortening at 120-ms bin before EMG onset. Furthermore, the lateralized MRP commenced at about 80 ms before EMG onset, indicating that TMS influences the cortical motor circuitry around 30-40 ms before the activation of the primary motor cortex. In contrast, for the left hand, we were faced with some uncertain concepts as human handedness and hemisphere asymmetries in both measures of RT and MRP, and thus it was not possible to substantiate about the motor specific effect of subthreshold TMS.

Action Potentials↗
PubMed1999

Cerebral acetylcholine levels and long-term spatial cognitive impairment following middle cerebral artery occlusion in rats.

The behavioral and neurochemical changes in the chronic phase of permanent occlusion of the right middle cerebral artery (MCA) in rats were investigated. Nineteen MCA-occluded rats failed to solve the 8-arm radial maze task (cognitively impaired rats), while 11 MCA-occluded rats could complete it (cognitively unimpaired rats). When a delay of 60 min was imposed in the task, however, 5 cognitively unimpaired rats failed to complete the task. The rats that underwent behavioral testing were studied for any changes in ACh levels in various brain regions using HPLC with electrochemical detection. The ACh levels in the infarcted areas decreased considerably in all MCA-occluded rats, but no region of the infarcted areas correlated with the spatial cognitive deficit. The ACh levels tended to decrease in the frontal cortex of the cognitively impaired rats and greatly increased in both ipsilateral and contralateral parietal cortex of the cognitively unimpaired rats. A significant correlation was observed between the ACh levels and spatial cognitive deficit in the contralateral frontal cortex, and ipsilateral and contralateral parietal cortex. These results suggest that the cholinergic function of the frontal and parietal cortices might play a role in acquiring spatial cognition in MCA-occluded rats.

Acetylcholine↗
PubMed1999

[Relationship between hippocampal arachidonic acid content and induction of LTP in aged rats].

There are several lines of evidence indicating that membrane AA correlates with the ability of aged rats to sustain LTP. The age-related decrease in membrane AA seems to be triggered by increased lipid peroxidation, which is involved with the decline of LTP. The chronic treatment of DHA could decrease membrane AA without an increase in lipid peroxidation. We have thus investigated the effect of chronic treatment of DHA on hippocampal LTP to assess whether the decrease in membrane AA could directly affect the induction of LTP. The effects of daily supplementation of DHA for 3 months on membrane AA, LTP, and Ca2+ response were evaluated using hippocampal slices from 26-month-old Wistar rats. Chronic treatment of DHA reduced the hippocampal AA significantly, but did not change the amplitude of LTP. Neither 30 mM K+ nor 500 microM NMDA-induced Ca2+ response was affected by chronic treatment of DHA, while the 500 microM carbachol-induced Ca2+ response was reduced. From these results, the reduction of membrane AA might suppress the carbachol-induced Ca2+ response by inhibiting the muscarinic receptor function, IP3 formation and/or Ca2+ release from Ca2+ stores by IP3. However, the reduction of membrane AA is not likely to be a main causal factor of the decline of LTP.

Aging↗
PubMed1999

A non-nitrergic smooth muscle relaxant factor released from rat urinary bladder by muscarinic receptor stimulation.

PURPOSE: To study the possible release of a relaxant factor from isolated rat bladder tissue. MATERIALS AND METHODS: Thoracic aortae and urinary bladders were obtained from 55 female Sprague-Dawley rats. The bladder body was used in its original tubular shape as the donor tissue in a co-axial bioassay system, and the aorta served as acceptor tissue. RESULTS: In a co-axial bioassay system with endothelium-free, norepinephrine-contracted, rat aortic preparations mounted within urothelium-intact urinary bladder, carbachol caused a concentration-dependent relaxation, amounting to 64+/-7% (n = 10) of the induced contraction, suggesting release of a relaxing factor. The relaxant effect of carbachol was lost if the urinary bladder segment was removed. However, the relaxation was affected neither by removal of the urothelium, nor by bladder segment inversion. It was resistant to inhibition of the L-arginine/nitric oxide and cyclo-oxygenase pathways, and unaffected by beta-adrenoceptor blockade and K+ channel inhibition. The relaxation was not associated with any significant changes in the intracellular levels of cGMP or cAMP. CONCLUSION: A previously unrecognized non-adrenergic, non-nitrergic, non-prostanoid inhibitory mediator is released from the rat urinary bladder by muscarinic receptor stimulation. The physiological importance of such a factor remains to be established.

Animals↗
PubMed1998

Involvement of caspase-like proteinases in apoptosis of neuronal PC12 cells and primary cultured microglia induced by 6-hydroxydopamine.

Activation of proteolytic enzymes, including the caspase family of proteinases, is a feature characteristic of the apoptotic program. In the present study, we examined a potential role of intracellular proteinases in the death of neuronal PC12 and primary cultured rat microglial cells induced by 6-hydroxydopamine (6-OHDA). In both neuronal PC12 and microglial cells, 6-OHDA (10-200 microM) induced apoptosis in a dose-dependent manner as judged by the DNA break. The 6-OHDA was ineffective in Bcl-2-overexpressing neuronal PC12 cells. Pretreatment of these cells with two caspase inhibitors, acetyl-Try-Val-Ala-Asp-aldehyde and acetyl-Asp-Glu-Val-Asp-aldehyde, prevented the 6-OHDA-induced apoptosis. Pepstatin A and leupeptin, potent inhibitors of aspartic and cysteine proteinases, respectively, partly inhibited the apoptosis of microglia but not neuronal PC12 cells. In contrast, GBR12935, a dopamine uptake inhibitor, significantly inhibited the apoptotic death of neuronal PC12 cells but not microglia. These results suggest that mechanisms by which 6-OHDA induces apoptosis in these two cell types are distinct; 6-OHDA incorporated into neuronal PC12 cells and its metabolites may activate the caspase-like enzymes, whereas oxidative metabolites of the agent produced extracellularly may activate the caspase and the endosomal/lysosomal proteolytic systems in microglia.

Animals↗
PubMed1998

An aquaporin-2 water channel mutant which causes autosomal dominant nephrogenic diabetes insipidus is retained in the Golgi complex.

Mutations in the aquaporin-2 (AQP2) water channel gene cause autosomal recessive nephrogenic diabetes insipidus (NDI). Here we report the first patient with an autosomal dominant form of NDI, which is caused by a G866A transition in the AQP2 gene of one allele, resulting in a E258K substitution in the C-tail of AQP2. To define the molecular cause of NDI in this patient, AQP2-E258K was studied in Xenopus oocytes. In contrast to wild-type AQP2, AQP2-E258K conferred a small increase in water permeability, caused by a reduced expression at the plasma membrane. Coexpression of wild-type AQP2 with AQP2-E258K, but not with an AQP2 mutant in recessive NDI (AQP2-R187C), revealed a dominant-negative effect on the water permeability conferred by wild-type AQP2. The physiologically important phosphorylation of S256 by protein kinase A was not affected by the E258K mutation. Immunoblot and microscopic analyses revealed that AQP2-E258K was, in contrast to AQP2 mutants in recessive NDI, not retarded in the endoplasmic reticulum, but retained in the Golgi compartment. Since AQPs are thought to tetramerize, the retention of AQP2-E258K together with wild-type AQP2 in mixed tetramers in the Golgi compartment is a likely explanation for the dominant inheritance of NDI in this patient.

Adult↗