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Biomedical subjects

M Kondo

Publications and source records attributed to M Kondo.

At least 397 records · Page 22Linked to original sources
PubMed1998

Involvement of macrophage migration inhibitory factor (MIF) in the mechanism of tumor cell growth.

BACKGROUND: Macrophage migration inhibitory factor (MIF) was recently rediscovered as a cytokine, pituitary hormone, and glucocorticoid-induced immunomodulator. MIF is constitutively expressed in various cells and enhances production of inflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1, and interferon gamma. Recently, it was reported that MIF mRNA was overexpressed in prostatic tumors, which suggests that MIF is a protein involved in tumor cell growth beyond inflammatory and immune responses. MATERIALS AND METHODS: We examined the expression of MIF in the murine colon carcinoma cell line colon 26 by Western and Northern blot analyses and immunohistochemistry. Next, we investigated the effects of transforming growth factor (TGF) beta, basic fibroblast growth factor (b-FGF), and platelet-derived growth factor (PDGF) on the expression of MIF mRNA. Furthermore, we examined whether MIF is involved in tumor cell proliferation, using an MIF anti-sense plasmid transfection technique. RESULTS: We demonstrated that MIF protein and its mRNA were highly expressed in colon 26 cells, using Western and Northern blot analyses, respectively. By immunohistochemical analysis, we found that MIF was localized largely in the cytoplasm of the tumor cells. In response to TGF-beta, b-FGF, and PDGF, MIF mRNA expression was significantly up-regulated. Following this, we transfected the cells with an anti-sense MIF plasmid, which revealed that this treatment induced significant suppression of cell proliferation. CONCLUSION: Although MIF plays multifunctional roles in a broad spectrum of pathophysiological states, little has been done to investigate the role of this protein in association with tumor growth. The current results suggest the possibility that MIF induces tumor cell growth in concert with other growth factors, which encouraged us to investigate a novel approach for tumor therapy using an anti-MIF antibody and an MIF anti-sense plasmid transfection technique.

Animals↗
PubMed1997

Identification of clonogenic common lymphoid progenitors in mouse bone marrow.

The existence of a common lymphoid progenitor that can only give rise to T cells, B cells, and natural killer (NK) cells remains controversial and constitutes an important gap in the hematopoietic lineage maps. Here, we report that the Lin(-)IL-7R(+)Thy-1(-)Sca-1loc-Kit(lo) population from adult mouse bone marrow possessed a rapid lymphoid-restricted (T, B, and NK) reconstitution capacity in vivo but completely lacked myeloid differentiation potential either in vivo or in vitro. A single Lin(-)IL-7R(+)Thy-1(-)Sca-1loc-Kit(lo) cell could generate at least both T and B cells. These data provide direct evidence for the existence of common lymphoid progenitors in sites of early hematopoiesis.

Animals↗
PubMed1997

Establishment of human peripheral lung epithelial cell lines (HPL1) retaining differentiated characteristics and responsiveness to epidermal growth factor, hepatocyte growth factor, and transforming growth factor beta1.

Novel human epithelial cell lines retaining characteristic features of normal peripheral airway cells were established by transfecting the SV40 large T antigen gene into primary in vitro outgrowths from normal peripheral lung specimens. These lines, designated as HPL1A to HPL1E, showed the polygonal shapes typical of epithelial cells and expressed cytokeratin in abundance. Ultrastructural examination revealed the presence of microvilli, multivesicular bodies, and multilamellar body-like structures that are characteristic of type II pneumocytes, but expression of CC1O transcripts, a highly specific marker for Clara cells, was also observed. Response to transforming growth factor beta, epidermal growth factor (EGF), and hepatocyte growth factor, all of which are thought to be important growth-regulatory molecules for cellular proliferation and developmental processes of peripheral lung, was apparent. In the HPL1A case, markedly altered cell morphology and cytoskeletal organization, potent inhibition of cell growth, and increased expression of an extracellular matrix protein were noted with transforming growth factor beta. Interestingly, both EGF and hepatocyte growth factor stimulated anchorage-dependent growth, whereas only EGF could sustain anchorage-independent proliferation. The HPL1 lines are, to our knowledge, the first series of stable epithelial lines of human peripheral lung to be described. They should be valuable for investigating various aspects of growth regulation and oncogenic processes, including the mechanisms of acquisition of anchorage independence and the interrelationships of genetic changes identified previously in lung cancers. In addition, the HPL1 lines may also prove useful for development of in vitro models for other human lung disorders as well as to elucidate the mechanisms of peripheral lung differentiation.

Aged↗
PubMed1997

Efficient gene transduction by Epstein-Barr-virus-based vectors coupled with cationic liposome and HVJ-liposome.

We show here a novel non-viral strategy to transduce human cells by using an EBV-based vector system. The EBV-based vectors, the plasmid vectors carrying EBV oriP (origin for plasmid replication) and EBNA (EBV nuclear antigen) 1 gene from EBV genome, were combined with 2 gene delivery systems, i.e., cationic liposome and HVJ-liposome. By both methods, EBV-based vectors could be more efficiently transfected into HeLa cells than non-EBV, conventional plasmid vectors. When human primary fibroblasts were transfected, EBV-based vectors coupled with cationic liposome but HVJ-liposome resulted in successful gene transduction, while human bone marrow cells were transduced with both HVJ-liposome- and cationic liposome-EBV vectors. These results suggest the potential applications of the EBV-based vector system for gene therapy.

Bone Marrow Cells↗
PubMed1997

The AtVAM3 encodes a syntaxin-related molecule implicated in the vacuolar assembly in Arabidopsis thaliana.

The vacuole constitutes a large compartment in plant and fungal cells. The VAM3 gene of Saccharomyces cerevisiae encodes a syntaxin-related protein required for vacuolar assembly. An Arabidopsis thaliana cDNA library, designed for expression in S. cerevisiae, was screened for cDNAs able to complement defective vacuolar assembly of the Deltavam3 mutation. One cDNA, encoding a 33-kDa protein with structural similarities to the other syntaxins, was identified. The product of AtVAM3 (AtVam3p) was expressed in various tissues including roots, leaves, inflorescence stems, flower buds, and young siliques. The AtVAM3 transcripts were abundant in undifferentiated cells in the meristematic region. AtVam3p fractionated predominantly to an 8,000 x g pellet fraction where a vacuolar membrane protein H+-translocating inorganic pyrophosphatase (H+-PPase) also fractionated. Immunoelectron microscopy showed that AtVam3p was localized to restricted regions on the vacuolar membranes. We propose that AtVam3p provides the t-SNARE function in the vacuolar assembly in A. thaliana.

Amino Acid Sequence↗
PubMed1997

Selective innervation of different target tissues in guinea-pig cranial exocrine glands by sub-populations of parasympathetic and sympathetic neurons.

This study has used multiple-labelling immunohistochemistry and quantitative analysis to examine the projections of subpopulations of parasympathetic and sympathetic neurons to different vascular and secretory structures in five cranial exocrine glands of guinea-pigs. Multiple subpopulations of parasympathetic axons, identified by immunoreactivity (IR) for various combinations of peptides, innervated arteries, arterioles, ducts and acini in sublingual, submandibular, parotid, lacrimal and zygomatic glands, although axons were absent from ducts in the parotid gland. Most parasympathetic axons contained IR for vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), with or without enkephalin (Enk). The proportion of parasympathetic axons that contained Enk-IR varied greatly between target tissues and glands: Enk-IR was more common in axons supplying secretory ducts, acini and arterioles than in axons innervating more proximal arteries; Enk-IR was less common in axons supplying the lacrimal gland than axons supplying the submandibular, lacrimal and zygomatic glands. Sympathetic axons with IR for tyrosine hydroxylase (TH) innervated arterial vessels in all glands, but innervated secretory structures only in the salivary glands. Sympathetic axons supplying proximal arterial segments often contained NPY-IR and sometimes also contained IR for dynorphin. Dynorphin-IR was more common in axons in the parotid, lacrimal and zygomatic glands than in the sublingual and submandibular glands. In contrast, axons supplying arterioles, ducts and acini lacked peptide IR. These results indicate that neuronal pathways regulating proximal arteries in cranial exocrine glands are different from the neuronal pathways regulating arterioles and acini, and may be different from neurons projecting to proximal secretory ducts. Furthermore, the peptides enkephalin, NPY and dynorphin are likely to make variable contributions to autonomic neurotransmission in different arterial segments and in different cranial exocrine glands.

Animals↗
PubMed1997

Plus- and minus-stranded hepatitis G virus RNA in liver tissue and in peripheral blood mononuclear cells.

Hepatitis G virus (HGV), which was recently identified, is a single, plus-stranded RNA virus that is thought to replicate via minus-stranded RNA, but no information is available about the distribution of either plus- (genomic) or minus- (replicative) stranded HGV RNAs in HGV infected patients. We, therefore, tested the serum, liver tissue, and peripheral blood mononuclear cells (PBMCs) of six hepatitis patients with HGV infection for the presence of plus- and minus-stranded HGV RNA. The RT-nested PCR was used with primers derived from 5'-noncoding region of the genome. Before RT-PCR analysis, the 3'-termini of RNA specimens were chemically modified to discriminate between plus- and minus-stranded HGV RNA. Plus-stranded HGV RNA was detected in the serum and liver tissue of all six patients and in the PBMCs of five patients. Minus-stranded RNA was detected in the liver tissue of all six patients, in the serum of two patients, and in the PBMCs of one patient. In summary, the detection of minus-stranded HGV RNA in liver tissue may indicate that HGV replicates in the liver.

Flaviviridae↗
PubMed1997

Advanced glycation end products induce expression of vascular endothelial growth factor by retinal Muller cells.

Recent studies have suggested that advanced glycation end products (AGEs) are involved in the development of diabetic complications. To assess the pathogenic role of AGEs and vascular endothelial growth factor (VEGF) in the development of retinal neovascularization in diabetic retinopathy, we investigated the effect of AGEs on induction of VEGF by retinal Muller cells and measured AGE and VEGF concentrations in the vitreous of patients with proliferative diabetic retinopathy (PDR) and nondiabetic patients. The expression of VEGF mRNA and the production of VEGF protein by cultured Muller cells were enhanced by the presence of AGEs. The vitreous concentrations of AGEs and VEGF were both elevated in patients with PDR compared with patients without diabetes (P < 0.01). There was a moderate positive correlation between the levels of crossline and VEGF (r=0.698, P < 0.01). Elevation of AGEs in the vitreous may promote intraocular neovascularization in diabetic retinopathy through production of VEGF from Muller cells.

Aged↗
PubMed1997

Pyridoxine refractory X-linked sideroblastic anemia caused by a point mutation in the erythroid 5-aminolevulinate synthase gene.

To elucidate how pyridoxine-refractory X-linked sideroblastic anemia (XLSA) develops, we analyzed the erythroid-specific 5-aminolevulinate synthase (ALAS-E) gene of a patient with the anemia. The activity and amount of the enzyme in bone marrow cells of the patient were found to be approximately 5% of the normal control. We identified a point mutation, which introduces an amino acid substitution from Asp 190 to Val. In transient transfection analyses using quail fibroblasts, accumulation of aberrantly processed proteins, the sizes of which were larger than that of mature ALAS-E, was found in mitochondria. The proteins were reproducibly detected in assays combining in vitro transcription/translation of ALAS-E precursor and import of the precursor into isolated mouse mitochondria. These results suggest that the mutation causing pyridoxine-refractory XLSA affects the processing of the ALAS-E precursor, thus provoking instability of the ALAS-E protein.

5-Aminolevulinate Synthetase↗
PubMed1997

Amidophosphoribosyltransferase limits the rate of cell growth-linked de novo purine biosynthesis in the presence of constant capacity of salvage purine biosynthesis.

Factors controlling relative flux rates of the de novo and salvage pathways of purine nucleotide biosynthesis during animal cell growth are not fully understood. To examine the relative role of each pathway for cell growth, three cell lines including CHO K1 (a wild-type Chinese hamster ovary fibroblast cell line), CHO ade -A (an auxotrophic cell line deficient of amidophosphoribosyltransferase (ATase), a presumed rate-limiting enzyme of the de novo pathway), and CHO ade -A transfected with human ATase cDNA (-A+hATase) resulting in 30-350% of the ATase activity of CHO K1, were cultured in purine-rich or purine-free media. Based on the enzyme activities of ATase and hypoxanthine phosphoribosyltransferase, the metabolic rate of the de novo and salvage pathways, the rate of cell growth (growth rate) in three cell lines under various culture conditions, and the effect of hypoxanthine infusion on the metabolic rate of the de novo pathway in rat liver, we concluded the following. 1) In -A+hATase transfectants, ATase activity limits the rate of the de novo pathway, which is closely linked with the growth rate. 2) Purine nucleotides are synthesized preferentially by the salvage pathway as long as hypoxanthine, the most essential source of purine salvage, can be utilized, which was confirmed in rat liver in vivo by hypoxanthine infusion. The preferential usage of the salvage pathway results in sparing the energy expenditure required for de novo synthesis. 3) The regulatory capacity of the de novo pathway (about 200%) was larger than that of the salvage pathway (about 20%) with constant hypoxanthine phosphoribosyltransferase activity.

Amidophosphoribosyltransferase↗
PubMed1997

Bcl-2 rescues T lymphopoiesis in interleukin-7 receptor-deficient mice.

Mice lacking functional IL-7 or IL-7R alpha genes are severely deficient in developing thymocytes, T cells, and B cells. IL-7 and IL-7 receptor functions are believed to result in lymphoid cell proliferation and cell maturation, implying signal transduction pathways directly involved in mitogenesis and elaboration of developmentally specific new gene programs. Here, we show that enforced expression of the bcl-2 gene in T-lymphoid cells (by crossing in the Emu-bcl-2 transgene) in IL-7R alpha-deficient mice results in a significant restoration of thymic positive selection and T cell numbers and function. We propose cell survival signals to be the principal function of IL-7R engagement in thymic and T cell development.

Animals↗
PubMed1997

Efficacy of hyperthermia and polyunsaturated fatty acids on experimental carcinoma.

We investigated the efficacy of hyperthermia and gamma-linolenic acid on experimental carcinoma. This study focused on polyunsaturated fatty acids that are substrates for free radical reactions. Oleic acid, linolenic acid, alpha-linolenic acid, or gamma-linolenic acid was injected into the arteries feeding AH109A carcinoma implanted into rat hind limbs. Among these, gamma-linolenic acid had the greatest effect on tumor tissue lipid peroxidation and demonstrated an antitumor effect. Consequently, gamma-linolenic acid injection into the feeding artery of a tumor was performed immediately prior to hyperthermia. This combination therapy induced a high level of lipid peroxidation in tumor tissue and a significant antitumor effect. Hyperthermia combined with gamma-linolenic acid produces free radical reactions by increasing the radical reaction substrate and may be an effective anticancer modality.

Animals↗
PubMed1997

An aspartic endopeptidase is involved in the breakdown of propeptides of storage proteins in protein-storage vacuoles of plants.

To understand the mechanism of the maturation of various proteins in protein-storage vacuoles, we purified a 48-kDa aspartic endopeptidase composed of 32-kDa and 16-kDa subunits from castor bean. Immunocytochemical and cell fractionation analyses of the endosperm of maturing castor bean seed showed that the aspartic endopeptidase was localized in the matrix of the protein-storage vacuoles, where a variety of seed storage proteins were also present. The amount of the aspartic endopeptidase increased at the mid-maturation stage of the seeds before accumulation of the storage proteins. To determine how the aspartic endopeptidase is responsible for maturation of seed proteins in concert with the vacuolar processing enzyme, we prepared 35S-labeled proproteins of seed proteins from the endoplasmic reticulum fraction of pulse-labeled maturing endosperm and used the authentic proproteins as substrates for in vitro processing experiments. The purified aspartic endopeptidase was unable to convert any of three endosperm proproteins, pro2S albumin, proglobulin, and proricin, into their mature sizes, while the purified vacuolar processing enzyme could convert all three proproteins. We further examined the activity of aspartic endopeptidase on the cleavage of an internal propeptide of Arabidopsis pro2S albumin, which is known to be removed post-translationally. The aspartic endopeptidase cleaved the propeptide at three sites under acidic conditions. These results suggest that aspartic endopeptidase cannot directly convert pro2S albumin into the mature form, but it may play a role in trimming the C-terminal propeptides from the subunits that are produced by the action of the vacuolar processing enzyme.

2S Albumins, Plant↗
PubMed1997

Effects of aminoguanidine on systemic inflammatory response syndrome induced by platelet activating factor and by lipopolysaccharide in rats.

We investigated the effects of aminoguanidine, a relatively selective inhibitor of inducible nitric oxide (NO) synthase, on the systemic inflammatory response syndrome induced by platelet activating factor (PAF) and by lipopolysaccharide in rats, with emphasis on NO production in vivo. Aminoguanidine treatment improved survival rates after lipopolysaccharide challenge, whereas it aggravated the lethality caused by PAF. Lipopolysaccharide induced a marked increase in the concentrations of nitrate and nitrite in plasma compared with vehicle administration, and the increase was prevented by aminoguanidine. In contrast, PAF challenge with or without aminoguanidine did not affect the concentrations of nitrate and nitrite in plasma compared with vehicle administration. These results suggest that NO derived from inducible NO synthase is not a major participant in the systemic inflammatory response syndrome induced by PAF. Aminoguanidine is not likely to provide beneficial effects in conditions where PAF is produced and the concentrations of nitrate and nitrite in plasma are not significantly increased.

Animals↗
PubMed1997

Combinations of AMPA receptor subunit expression in individual cortical neurons correlate with expression of specific calcium-binding proteins.

The functional properties of AMPA-type glutamate receptors are determined by their subunit composition. We detected the expression of the AMPA receptor subunits (GluR1-GluR4) in neurons in the somatosensory cortex of adult rats by combining nonradioactive in situ hybridization using digoxigenin-labeled RNA probes of GluR1 and GluR2 with immunocytochemistry using specific antibodies against GluR1, GluR2/3, and GluR4. On the basis of differential expression of the GluR1 and GluR2 subunits, we classified the cortical neurons into four categories. To correlate the differential expression of AMPA receptor subunits in each neuron with that of two calcium-binding proteins, parvalbumin and calbindin-D28k, we used a triple-labeling method. The majority of cortical neurons ( approximately 2/3) showed expression of GluR2 and undetectable expression of GluR1. GluR1-/GluR2-expressing neurons and GluR1-expressing/GluR2-undetectable neurons comprised approximately 1/10 each. Regarding the morphology, most GluR1-undetectable/GluR2-expressing neurons were pyramidal cells in layers II/III, V, and VI, whereas most GluR1-expressing/GluR2-undetectable neurons were nonpyramidal cells in layers II-VI. The GluR1-/GluR2-expressing neurons were either pyramidal or nonpyramidal. The majority of GluR1-/GluR2-expressing nonpyramidal cells was intensely stained with monoclonal antibody against calbindin-D28k, and one-half of the GluR1-undetectable/GluR2-expressing pyramidal neurons in layer II/III were lightly stained with this antibody. Most of GluR1-expressing/GluR2-undetectable neurons possessed parvalbumin immunoreactivity. These results indicate that neurons in the rat somatosensory cortex express differential combinations of GluR subunits, which correlate with the specific expression of the calcium-binding proteins.

Animals↗