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Biomedical subjects

A Mizoguchi

Publications and source records attributed to A Mizoguchi.

At least 73 records · Page 4Linked to original sources
PubMed1999

Cloning and characterization of a novel membrane-associated antigenic protein of Helicobacter pylori.

Infection by Helicobacter pylori, a noninvasive bacterium, induces chronic leukocyte infiltration in the stomach by still largely unknown molecular mechanisms. We investigated the possibility that a membrane protein of H. pylori induces an inflammatory reaction in the subepithelial tissue of the stomach. By generating an expression library of H. pylori chromosomal DNA and screening with rabbit antiserum raised to a membrane fraction of H. pylori and sera of infected patients, we cloned a 16.0-kDa protein (HP-MP1) which appeared to attach to the inner membrane of the H. pylori in a homodimeric form. Anti-HP-MP1 antibodies were detected in the sera of infected patients but not in those of uninfected controls. Coincubation of monocytes with recombinant HP-MP1 led to cell activation and production of interleukin-1alpha (IL-1alpha), tumor necrosis factor alpha, IL-8, and macrophage inflammatory protein 1alpha. The results indicate that HP-MP1 is an antigenic membrane-associated protein of H. pylori which potentially activates monocytes. This suggests that HP-MP1 may play roles in the pathogenesis of perpetual tissue inflammation associated with H. pylori infection.

Antibodies, Bacterial↗
PubMed1999

Bronchiectasis with myeloperoxidase antineutrophil cytoplasmic antibody and bactericidal/permeability-increasing protein antineutrophil cytoplasmic antibody.

A 56-year-old woman was hospitalized for recurrent hemoptysis. She had been suffering from bronchiectasis for 4 years. Pseudomonas aeruginosa was persistently detected in her sputum. Serum was positive for Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) and bactericidal/permeability-increasing protein antineutrophil cytoplasmic antibody (BPI-ANCA). She underwent lung resection. Histopathologically, the resected lung showed bronchiectasis with pulmonary fibrosis but did not show vasculitis. Her serum became negative for the ANCAs after the operation. To date, she has no recurrence of hemoptysis. We discuss this case of bronchiectasis with MPO-ANCA and BPI-ANCA and suggest a possible role for ANCAs in chronic airway infection.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1999

[Clinical investigation of 15 patients with pulmonary cryptococcosis--clinical comparison of HTLV-I carriers and non-carriers].

We investigated 15 pulmonary cryptococcosis patients. The group had a mean age of 51.7 years, and 6 (40%) of the patients were women. Cryptococcosis was primary in 13 patients and secondary in 2 (diabetes mellitus and smoldering adult T-cell leukemia). Eight patients were asymptomatic and 9 patients were detected by medical examinations. Dry cough was the most common symptoms. On chest radiographs, 5 patients showed solitary nodules, 4 patients showed infiltrative shadows, and 4 patients showed multiple nodules. The right lower lobe was the predominant location of solitary nodules, and the left upper and middle lung fields were the predominant locations of infiltrative shadows. Transbronchial lung biopsy was the method of diagnosis for 9 patients, and open lung biopsy for the others. Eleven patients were treated with fluconazole, and the mean treatment period was 7 months. Four patients underwent, resection procedures only, and experienced no recurrence. Five patients were positive for HTLV-I (one had smoldering ATL) and 5 were negative. Eighty percent of the HTLV-I positive patients had some symptoms and 80% of the HTLV-I negative patients were asymptomatic. HTLV-I positive patients showed various pulmonary shadows and 80% of the HTLV-I negative patients showed solitary nodules. The pulmonary lesions in HTLV-I positive patients were more extensive than those in HTLV-I negative patients (p < 0.05). We postulate the possible existence of subtle immunological abnormalities, including abnormalities of cellular immunity, in HTLV-I carriers.

Aged↗
PubMed1999

[Role of vesicle fusion mechanism and cell adhesion molecules in growth cone elongation and synaptogenesis].

Growth cones have been regarded to play central roles in forming complex neural network through target tract selection and target cell recognition. We have found that the vesicle fusion molecular system in growth cones is similar to that in synapses. The cleavage of SNAP25, a protein involved in neurotransmitter release in synapse, resulted in inhibition of neurite elongation. Inversely the overexpression of VAMP2/synaptobrevin, another protein involved in neurotransmitter release in synapse, in PC12 cells resulted in promotion of neurite elongation. We have recently isolated a novel components at cadherin-based cell-cell adherens junctions, named neurabin I, neurabin II, and afadin. Neurabin I is specifically expressed in nervous tissues and localized at synapses. Afadin is uviquitously expressed in various tissues and highly concentrated at cell-cell adherens junctions of small intestine epithelial cells, cardiac muscles, synapses. We have identified the transmembrane protein binding to afadin, and named it nectin, which belongs to immunoglobulin superfamily. Nectin, afadin, neurabin I, and neurabin II may be key molecules to find out various unknown guidance cues which can induce regenerating growth cones to repair the functional neuronal connections in central nervous system after injury.

Animals↗
PubMed1998

Regeneration of dorsal column axons after spinal cord injury in young rats.

In contrast to previous reports denying the occurrence of axonal regeneration of the dorsal column (DC) projections, here we demonstrate for the first time that marked regeneration occurs spontaneously after transection in infant rats. Transection was made sharply so as to produce edema-free lesions without subsequent formation of either scars or cysts. Transganglionic labeling of axons revealed that regenerated axons ascended in the normal tract in a manner similar to normal projections as a tightly-packed fasciculus and terminated densely in the nucleus gracilis. The present study indicates that failure of regeneration of DC axons is due to neither intrinsic deficiency of regrowth potential nor globally-inhospitable axonal environment but rather the local conditions of the lesion site.

Animals↗
PubMed1998

Molecular cloning and characterization of rat lin-10.

In Caenorhabditis elegans, the vulval induction is mediated by tyrosine kinase receptor/Ras signal transduction pathway composed of the lin-3, let-23, and let-60 products. In addition to these gene products, the lin-2, lin-7, and lin-10 products are also implicated in this pathway. Lin-2 encodes a MAGUK and lin-7 encodes a small protein with one PDZ domain. The lin-10 product has no homology to known proteins. Here, we have cloned a rat homologue of the lin-10 product and characterized it. Rat lin-10 is ubiquitously expressed in various rat tissues and distributed in both the cytosol and membrane fractions. In brain, however, rat lin-10 is distributed only in the membrane fraction and enriched in the synaptic plasma membrane and postsynaptic density fractions. These results suggest that rat lin-10 is involved at least in synaptic functions in brain.

Animals↗
PubMed1998

Neurabin-II/spinophilin. An actin filament-binding protein with one pdz domain localized at cadherin-based cell-cell adhesion sites.

In a preceding paper, we reported a novel actin filament (F-actin)-binding protein, named neurabin, which was specifically expressed in neural tissue and implicated in neurite formation. We purified from rat brain another F-actin-binding protein, which had a domain organization similar to that of neurabin but was ubiquitously expressed, and named it neurabin-II. The original neurabin, renamed neurabin-I, had 1095 amino acids and a calculated Mr of 122,729, whereas neurabin-II had 817 amino acids and a calculated Mr of 89, 642. Both neurabin-I and -II had one F-actin-binding domain at the N-terminal region, one PDZ domain at the middle region, a domain known to interact with transmembrane proteins, and domains predicted to form coiled-coil structures at the C-terminal region. Both neurabin-I and -II bound along the sides of F-actin and showed F-actin-cross-linking activity. The subcellular distribution analysis indicated that neurabin-II was enriched at the postsynaptic density fraction in rat brain and the adherens junction fraction in rat liver. Immunofluorescence microscopic analysis revealed that neurabin-II was highly concentrated at the synapse in primary cultured rat hippocampal neurons and at the cadherin-based cell-cell adhesion sites in Madin-Darby canine kidney cells. Neurabin-II turned out to be the same as a recently reported protein phosphatase 1-binding protein named spinophilin. These results suggest that neurabin-II/spinophilin plays an important role in linking the actin cytoskeleton to the plasma membrane.

Actins↗
PubMed1998

Localization of tyrosine-phosphorylated proteins in cultured mouse dorsal root ganglion neurons.

The present study, using confocal laser scanning microscopy and immunoelectron microscopy, examined the intracellular localization of tyrosine-phosphorylated proteins in cultured mouse dorsal root ganglion neurons with special reference to their growth cones. The growth cone is the specialized structure formed at the growing tip of the axon; characteristically highly motile with filopodia on the surface, it is responsible for the extension and guidance of the neurites to the appropriate targets during nerve regeneration. It has been suggested that protein-tyrosine phosphorylation plays an important role in the intracellular signal transduction that regulates the extension and motility of growth cones. By fluorescence immunocytochemistry, phosphotyrosine immunoreactivity was found in the growth cones and neurites. Some of the filopodia exhibited strong immunoreactivity at their tips. By immunoelectron microscopy, a large number of immunogold particles (gold particles conjugated to the secondary antibody) were seen to be distributed in the cytoplasm and some were observed on the plasma membrane in the growth cones, whereas in the neurites the density of immunogold particles was the same in the axoplasm as on the plasma membranes. These findings suggest that in the growth cones phosphotyrosines might mainly be involved in intracellular signaling for maintaining their high motility whereas in the neurites they might mostly be associated with the receptor proteins at the plasma membrane for adhesion as well as for growth of neurites. Thus, tyrosine phosphorylation might contribute to different functions for growth cones and neurites.

Animals↗
PubMed1998

Long acellular nerve transplants for allogeneic grafting and the effects of basic fibroblast growth factor on the growth of regenerating axons in dogs: a preliminary report.

Sciatic nerves were excised from 3 beagle dogs about 5 h after their sacrifice, treated three times by freezing and thawing, and stored in physiological saline for 3 months at -20 degrees C until used. Nerve segments 5 cm in length prepared from these stored nerves were transplanted to the common peroneal nerve in the right hindlimb of beagle dogs. Sixteen beagle dogs in total were used, in four treatment groups of two pairs each studied at 1 and 3 months. Five-hundred microliters basic fibroblast growth factor (bFGF) of two different concentrations (10 micrograms/300 microliters and 100 micrograms/300 microliters) which were impregnated in 0.5 ml gelatin hydrogels was applied around the sutured allografts. Autografting was also done in 4 beagle dogs, with no bFGF application. One month after the grafting, no regenerating nerves extended beyond the middle of the transplant in any of the allografts, except in the autografts in which a number of regenerated (myelinated) axons were present. Three months after the grafting, an abundance of myelinated axons was found at the middle of the graft: the numbers of axons per 10(4) micron 2 were 22.6 in the autografts and 10.6, 10.4 and 19.2 in the allografts treated with no bFGF, low-dose bFGF, and high-dose bFGF, respectively. Regenerating axons extended into the host nerve: the numbers of myelinated axons at the level 1.5 cm distal to the distal suture were 35.7, 0.9, 3.8, and 12.1 per 10(4) micron 2 in the above respective order. Although it was inferior in quality to the autograft, peripheral nerve regeneration was extensive in the distal nerve using freeze-thawed and bFGF-treated allografts at 3 months. Electromyography showed that the peroneus longus muscle responded to the electrical stimuli given at the site proximal to the transplant in all four groups. These data indicate that a 5-cm acellular nerve segment containing Schwann cell basal laminae can be used successfully as an allograft without any immunosuppressants and that exogenously applied bFGF can improve nerve regeneration by enhancing the growth of regenerating axons.

Animals↗
PubMed1998

Tomosyn: a syntaxin-1-binding protein that forms a novel complex in the neurotransmitter release process.

Syntaxin-1 is a component of the synaptic vesicle docking and/or membrane fusion soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) complex (7S and 20S complexes) in nerve terminals. Syntaxin-1 also forms a heterodimer with Munc18/n-Sec1/rbSec1 in a complex that is distinct from the 7S and 20S complexes. In this report, we identify a novel syntaxin-1-binding protein, tomosyn, that is capable of dissociating Munc18 from syntaxin-1 and forming a novel 10S complex with syntaxin-1, soluble N-etyhlmaleimide-sensitive factor attachment (SNAP) 25, and synaptotagmin. The 130 kDa isoform of tomosyn is specifically expressed in brain, where its distribution partly overlaps with that of syntaxin-1 in nerve terminals. High level expression of either syntaxin-1 or tomosyn results in a specific reduction in Ca2+-dependent exocytosis from PC12 cells. These results suggest that tomosyn is an important component in the neurotransmitter release process where it may stimulate SNARE complex formation.

Animals↗
PubMed1998

An autopsy case of peripheral neuroepithelioma in posterior mediastinum with p53 point mutation.

An 18-year old male was admitted to our hospital complaining of back pain. His chest computed tomography showed a tumor in the posterior mediastinum. Open biopsy was performed, and a diagnosis of peripheral neuroepithelioma was made. No genetic abnormalities were detected in the DNA obtained from the biopsy specimen. He received chemotherapy and radiation several times. These treatment regimens were effective, but he relapsed 14 months later and died of respiratory failure due to tumor growth. Autopsy examination revealed a large tumor which occupied almost the entire right thoracic cavity, but there was no evidence of metastasis to other organs. Chromosomal translocation t(14;17) (q24;p12.2) and point mutation of exon 5 of the p53 gene were detected.

Adolescent↗
PubMed1998

Two cases of idiopathic CD4+ T-lymphocytopenia in elderly patients.

We present 2 cases of idiopathic CD4+ T-lymphocytopenia (ICL) in elderly patients. Case 1, a 73-year-old man, with pneumonia had received several antibiotics with unsuccessful results at another hospital. On admission, his CD4+ T-lymphocyte count was 109/microl and Pneumocystis carinii was detected by bronchoalveolar lavage fluid staining. No evidence of human immunodeficiency virus (HIV) infection was found. Despite therapy, the patient died of respiratory failure. Case 2, a 72-year-old man, contracted severe pneumonia, and Hemophillus influenzae was believed to be the pathogen. On admission, his CD4+ T-lymphocyte count was 238/microl. No evidence of HIV infection was found. He received antibiotics and improved successfully. We suggest that ICL may currently be incubating in a number of elderly pneumonia patients.

Aged↗
PubMed1998

[A case of pulmonary infiltration with eosinophilia caused by Ascaris suum].

A 46-year old man was admitted to our hospital with dry cough and diarrhea. His chest CT showed diffuse subpleural small nodular shadows. Eosinophilia and an increase of serum IgE were detected. Eosinophils were also increased in BALF. An antibody against Ascaris suum was positive in serum while other causes of eosinophilia (e. g., drugs, fungus, collagen disease) were absent. Ivermectin was administered and the diarrhea improved within 3 days. The abnormal chest shadows and dry cough disappeared 3 months later. Pulmonary infiltration with eosinophilia (PIE) syndrome caused by Ascaris suum was diagnosed because of the clinical course and serum examination results. Recently, zoonoses are increasing with the boom of oversea travel and "natural" foods. We report a case of PIE syndrome caused by Ascaris suum and describe the clinical features and the social significance including the origin of this disease.

Animals↗
PubMed1998

[A case of pleuritis caused by strongyloides in a carrier of T-cell lymphoma virus type I (HTLV-I)].

A 73-year-old woman was admitted to our hospital complaining of dyspnea, fever and general edema. Chest roentgenogram showed bilateral pleural effusion and cardiomegaly. Cardiovascular examination demonstrated atrial tachycardia and left ventricle dysfunction, suggesting congestive heart failure. She was sero-positive for human T-cell lymphoma virus I (HTLV-I). The dyspnea and general edema improved after therapy for heart failure. Because the pleural effusion persisted after therapy, thoracentesis was performed. The pleural effusion was an exudate, and Strongyloides sterocoralis was detected by microscopy. Two courses of thiabendazole (1,500 mg/day, 3 days) were given orally. After this therapy, the pleural effusion improved markedly. This case suggests that Strongyloides stercoralis may be a causative agent of pleuritis in HTLV-I endemic areas.

Aged↗
PubMed1998

[Pulmonary sclerosing hemangioma with specific CT findings].

A 44-year-old woman was admitted to our hospital for evaluation of an abnormal lung shadow. Chest computed tomography (CT) revealed a tumor surrounded by air-space and an infiltrative shadow in the right S2. Right upper lobectomy was performed and pulmonary sclerosing hemangioma was diagnosed. Usually, pulmonary sclerosing hemangioma shows a solitary round nodule on a chest CT scan. We report a case of pulmonary sclerosing hemangioma with an unusual shadow on a chest CT scan, and review the literature.

Adult↗
PubMed1997

Neurabin: a novel neural tissue-specific actin filament-binding protein involved in neurite formation.

We purified from rat brain a novel actin filament (F-actin)-binding protein of approximately 180 kD (p180), which was specifically expressed in neural tissue. We named p180 neurabin (neural tissue-specific F-actin- binding protein). We moreover cloned the cDNA of neurabin from a rat brain cDNA library and characterized native and recombinant proteins. Neurabin was a protein of 1,095 amino acids with a calculated molecular mass of 122,729. Neurabin had one F-actin-binding domain at the NH2-terminal region, one PSD-95, DlgA, ZO-1-like domain at the middle region, a domain known to interact with transmembrane proteins, and domains predicted to form coiled-coil structures at the COOH-terminal region. Neurabin bound along the sides of F-actin and showed F-actin-cross-linking activity. Immunofluorescence microscopic analysis revealed that neurabin was highly concentrated in the synapse of the developed neurons. Neurabin was also concentrated in the lamellipodia of the growth cone during the development of neurons. Moreover, a study on suppression of endogenous neurabin in primary cultured rat hippocampal neurons by treatment with an antisense oligonucleotide showed that neurabin was involved in the neurite formation. Neurabin is a candidate for key molecules in the synapse formation and function.

Actins↗