Biomedical subjects

Koh Nakata

Publications and source records attributed to Koh Nakata.

23 records · Page 2Linked to original sources

PubMed2003

Secondary pulmonary alveolar proteinosis associated with myelodysplastic syndrome.

A 47-year-old man, who had been diagnosed as myelodysplastic syndrome (MDS), complained of a severe cough and a high-grade fever. Chest CT disclosed scattered small nodules and ground-glass opacities with interlobular septal thickening in both lung fields and a mass lesion in the right lower lobe. Pathological findings of the ground-glass opacities and the mass lesion obtained by video-assisted thoracoscopic surgery revealed the accumulation of eosinophilic amorphous material in the alveoli and confirmed the diagnosis of pulmonary alveolar proteinosis (PAP). Autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF) in sera were below sensitivity, while the GM-CSF level was elevated in bronchoalveolar lavage fluid. He was diagnosed as secondary PAP associated with MDS.

Biopsy, Needle↗

PubMed2002

Maximal HIV-1 replication in alveolar macrophages during tuberculosis requires both lymphocyte contact and cytokines.

HIV-1 replication is markedly upregulated in alveolar macrophages (AM) during pulmonary tuberculosis (TB). This is associated with loss of an inhibitory CCAAT enhancer binding protein beta (C/EBPbeta) transcription factor and activation of nuclear factor (NF)-kappaB. Since the cellular immune response in pulmonary TB requires lymphocyte--macrophage interaction, a model system was developed in which lymphocytes were added to AM. Contact between lymphocytes and AM reduced inhibitory C/EBPbeta, activated NF-kappaB, and enhanced HIV-1 replication. If contact between lymphocytes and macrophages was prevented, inhibitory C/EBPbeta expression was maintained and the HIV-1 long terminal repeat (LTR) was not maximally stimulated although NF-kappaB was activated. Antibodies that cross-linked macrophage expressed B-7, and vascular cell adhesion molecule and CD40 were used to mimic lymphocyte contact. All three cross-linking antibodies were required to abolish inhibitory C/EBPbeta expression. However, the HIV-1 LTR was not maximally stimulated and NF-kappaB was not activated. Maximal HIV-1--LTR stimulation required both lymphocyte-derived soluble factors, and cross-linking of macrophage expressed costimulatory molecules. High level HIV-1--LTR stimulation was also achieved when IL-1beta, IL-6, and TNF-beta were added to macrophages with cross-linked costimulatory molecules. Contact between activated lymphocytes and macrophages is necessary to down-regulate inhibitory C/EBPbeta, thereby derepressing the HIV-1 LTR. Lymphocyte-derived cytokines activate NF-kappaB, further enhancing the HIV-1 LTR.

Blotting, Western↗

PubMed2002

Genetic variants of human beta-defensin-1 and chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is due to interactions between cigarette smoke exposure and other risk factors. Genetic variations of human beta-defensin-1 (hBD-1), an endogenous antimicrobial peptide in the airway, were investigated in 60 patients and 213 healthy volunteers by single-strand conformation and restriction fragment length polymorphism analysis and DNA sequencing. Four nucleotide variations in the 5' and 3' untranslated regions and two nonsynonymous substitutions in the coding region were identified. Of these, a newly found Ile38 variant was observed in 15.0% of patients but only in 2.8% of healthy individuals and was significantly associated with the disease (OR = 6.1, 95% confidence intervals 2.0-8.3, P = 0.0012). More than 80% of those with Ile38 experienced sputum production for more than 3 months during the follow-up period. Genetic variations in hBD-1 may define a high-risk subgroup of COPD where the component of chronic bronchitis is predominant.

Aged↗

PubMed2002

Oligoclonal T cell expansions in pulmonary lymphoproliferative disorders: demonstration of the frequent occurrence of oligoclonal T cells in human immunodeficiency virus-related lymphoid interstitial pneumonia.

We used a denaturing gradient gel electrophoresis (DGGE) procedure with 40-nucleotide guanine- and cytosine-rich sequences in the polymerase chain reaction (PCR) and sequencing analysis to analyze the T cell antigen receptor (TCR)-Vgamma gene repertoire of infiltrating T lymphocytes in pulmonary lymphoproliferative disorders. Six of 15 low-grade mucosa-associated lymphoid tissue (MALT) lymphomas and 8 of 15 cases of lymphocytic interstitial pneumonia (LIP) showed some oligoclonal bands for TCR-Vgamma genes on DGGE. Sequencing analysis demonstrated plural oligoclonal TCR-Vgamma clones among the oligoclonal PCR products on DGGE, leading to the conclusion that conventional antigen-specific oligoclonal expansions may play some role in the pathogenesis of pulmonary lymphoproliferative disorders. The frequency of oligoclonal infiltrating T cell expansions in human immunodeficiency virus (HIV)-related LIP (100%) was significantly higher than in low-grade pulmonary MALT lymphomas (40%) or in HIV-negative LIP (30%). Because recent evidence demonstrates that the V3 loop in the proviral amino acid sequences of mononuclear cells from bronchoalveolar lavage is more homogeneous than those from peripheral blood, this homogeneity might result in oligoclonal expansions of infiltrating T lymphocytes as a consequence of ongoing reactions against lung-specific viral strains.

Adult↗

PubMed2002

[The mechanism of HIV replication at the site of inflammation coinfected with HIV and M. tuberculosis].

HIV-1 replication is remarkably augmented in macrophages at the site of inflammation due to tuberculosis. Reduction of expression of an inhibitory C/EBP beta transcription factor and activation of NF-kappa B are observed at the site of inflammation. Of 18 paraffin embedded tissue sections of HIV-tuberculosis coinfected autopsy or biopsy samples, 9 samples were positive for HIV-p24 staining, which were all derived from patients with blood CD4 cell counts more than 50/mm3. Moreover, the P24 positive cells were morphologically macrophages or epithelioid cells. CD4 positive lymphocytes consistently located near the P24 positive macrophages. Therefore, we hypothesized that lymphocyte-macrophage contact is important for maximal HIV production from macrophages. In vitro experiments showed that contact between lymphocytes and macrophages reduced inhibitory C/EBP beta, activated NF-kappa B and enhanced HIV-1 replication. If contact between lymphocytes and macrophages was prevented, inhibitory C/EBP beta expression was maintained and the HIV-1 long terminal repeat (LTR) was not maximally stimulated although NF-kappa B was activated. Antibodies which cross-linked macrophage expressed B-7, VCAM and CD40 were used mimic lymphocyte contact. Cross-linking antibodies abolished inhibitory C/EBP beta expression; however, the HIV-1 LTR was not maximally stimulated and NF-kappa B was not activated. Maximal HIV-1 LTR stimulation required both lymphocyte derived soluble factors and cross-linking of macrophage expressed costimulatory molecules. These results demonstrate that neither contact nor soluble factor(s) are sufficient to maximally enhance HIV-1 LTR activity in macrophages. Contact between activated lymphocytes and macrophages is necessary to down-regulate inhibitory C/EBP beta, thereby derepressing the HIV-1 LTR. Lymphocyte derived soluble factor(s) activate NF-kappa B, further enhancing the HIV-LTR.

CCAAT-Enhancer-Binding Protein-beta↗