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Biomedical subjects

M Kondo

Publications and source records attributed to M Kondo.

At least 253 records · Page 14Linked to original sources
PubMed1999

Primary culture of lymphoid organ cells and haemocytes of kuruma shrimp, Penaeus japonicus.

A primary cell culture system was developed for the cells of lymphoid organ tissue of kuruma shrimp, Penaeus japonicus. Minced tissues of lymphoid organs were seeded and incubated at 30 degrees C in medium 199 supplemented with 20% foetal bovine serum, a salt mixture and a lactalbumin hydrolysate (0.1 g/l). Fibroblast-like cells and epithelioid-like cells survived for 54 days. Cells did not survive after trypsin, collagenase or hyaluronidase treatment used for cell dissociation. Mitogens (Con A, PHA-P, Pokeweed) and insulin did not enhance cell proliferation. When penaeid rod-shaped DNA virus (PRDV) was inoculated into the lymphoid organ cell culture, a cytopathic effect was observed within 8 days. On the other hand, large granular haemocytes that were fractionated using a Percoll continuous density gradient were not infected with PRDV in vitro within 10 days, which was the longest period of haemocyte maintenance.

Animals↗
PubMed1999

Helicobacter pylori water extract induces interleukin-8 production by gastric epithelial cells.

In Helicobacter pylori-associated gastric mucosal injury, interleukin (IL) -8, a potent leukocyte chemoattractant, is produced by epithelial cells infected by H. pylori and directs neutrophils to the gastric mucosa. According to previous studies, the IL-8 production requires direct contact between the bacteria and epithelial cells. The aims of the present study were to determine whether an H. pylori water extract (HPE) induces IL-8 production by gastric epithelial cells and to characterize IL-8-inducing substances in HPE. Extracts were prepared from a standard strain and from strains obtained from patients with gastric ulcers. After addition of HPE to MKN 45 cells, a gastric cancer cell line, IL-8 in supernatants and IL-8 mRNA were measured by immunoassay and reverse transcription-polymerase chain reaction, respectively. For characterization, active fractions obtained by gel filtration of standard-strain HPE were treated by heating or trypsinization. To study the signal pathway leading to IL-8 production, inhibitors for protein kinase A (PKA), protein kinase C (PKC), or protein tyrosine kinase (PTK) were incubated with MKN45 cells before HPE stimulation. HPE from the standard strain and one of these clinical strains induced IL-8 production. Lipopolysaccharide or cagA in the strains showed no correlation with IL-8 concentration. Standard-strain HPE induced IL-8 mRNA expression in MKN 45 cells. Gel filtration localized activity to a low-molecular-weight fraction of about 7 kDa, which was resistant to heat and trypsin digestion. PKC inhibitors significantly blocked HPE-induced IL-8 production by MKN 45 cells; however, the PKA inhibitor or PTK inhibitors showed a partial inhibitory effect. HPE contains a nonprotein substance of low molecular weight that is responsible for IL-8 induction in gastric epithelial cells. This induction is mainly dependent on the activation of PKC but partially also dependent on PKA or PTK.

Cells, Cultured↗
PubMed1999

Nicotine induces uncoupling protein 1 in white adipose tissue of obese mice.

OBJECTIVE: To test the hypothesis that nicotine not only activates uncoupling protein1 (UCP1) in brown adipose tissue (BAT), but also induces UCP1 in white adipose tissue (WAT), which contributes to the mitigation of obesity in obese mice. DESIGN: Weights of the whole body, the gastrocnemius muscle, interscapular BAT and subcutaneous and retroperitoneal WAT, food intake and the mRNA and protein of UCP1 in these tissues were measured and immunohistochemistry using antiserum against UCP1 was also performed in obese yellow KK mice treated with nicotine for 6 months and control mice treated with physiological saline. RESULTS: Obese mice treated with nicotine for 6 months, compared with those injected with saline, weighed significantly less (P < 0.01) and had smaller subcutaneous and retroperitoneal WAT pads (P < 0.01), while obese mice that received nicotine ate less (P < 0.05) than those injected with saline. In mice treated with nicotine, the mRNA and protein of UCP1 was detected not only in BAT, but also in subcutaneous and retroperitoneal WATs. Immunohistochemically, the BAT of obese mice contained large lipid droplets and appeared rather WAT-like, but changed to typical brown adipocytes after nicotine treatment. The fat pads of nicotine-treated mice contained many multilocular cells that were positive for UCP1. CONCLUSION: Nicotine not only activates UCP1 in BAT, but also induces UCP1 in WAT and decreases food intake, which contributes to the mitigation of obesity.

Adipocytes↗
PubMed1999

Effect of vitamin E in gastric mucosal injury induced by ischaemia-reperfusion in nitric oxide-depleted rats.

BACKGROUND: Neutrophil infiltration and lipid peroxide accumulation are involved in reperfusion-induced gastric mucosal injury in nitric oxide-depleted rats. AIM: To assess the effect of vitamin E on this injury. METHODS: After ischaemia-reperfusion, the total area of erosions, lipid peroxide contents in gastric mucosa, and gastric neutrophil accumulation were compared between nitric oxide-depleted rats with deficient, normal, and increased vitamin E intake over 8 weeks. Thiobarbituric acid-reactive substances and tissue-associated myeloperoxidase activity were measured in gastric mucosa as indices of lipid peroxidation and neutrophil infiltration. RESULTS: The total area of erosions was significantly increased in the vitamin E-deficient group compared with the sufficient-intake and vitamin-supplemented groups. Both thiobarbituric acid-reactive substances and myeloperoxidase activity also were significantly increased in the vitamin E-deficient group compared with others. The total area of erosions closely paralleled the increases in both thiobarbituric acid-reactive substances and myeloperoxidase activity. CONCLUSION: These results indicate that the inhibition of lipid peroxidation and interference with neutrophil infiltration by vitamin E may be responsible for its cytoprotective effect in ischaemia-reperfusion.

Animals↗
PubMed1999

A novel mutation of the erythroid-specific delta-aminolaevulinate synthase gene in a patient with X-linked sideroblastic anaemia.

A novel missense mutation, A1754G, in exon 11 of the erythroid-specific delta-aminolaevulinate synthase gene (ALAS2) was identified in a Japanese male with sideroblastic anaemia. ALAS activity in bone marrow cells of the patient was reduced to 53.3% of the normal control. Consistent with this finding, activity of a bacterially expressed ALAS2 mutant protein harbouring this mutation was 19.5% compared with the normal control, but was increased up to 31.6% by the addition of pyridoxal 5'-phosphate (PLP) in vitro. RFLP analysis with Bsp HI restriction revealed that his mother was a carrier of the mutation. These findings suggest that A1754G mutation was inherited in this family in a manner consistent with X-linked inheritance, and is responsible for sideroblastic anaemia in the patient.

5-Aminolevulinate Synthetase↗
PubMed1999

Effect of shear stress and a stable prostaglandin I2 analogue on adhesive interactions of colon cancer cells and endothelial cells.

In the process of cancer metastasis, adhesion between cancer cells and endothelial cells is an important early step. In the present study, the effects of shear stress and the adhesion molecules responsible for cancer cell interactions with endothelial cells were investigated in a system similar to in vivo microcirculation. The effect of prostaglandin I2 (PGI2) also was determined. Human colon cancer cell line Colo 201 and human umbilical vein endothelial cells (HUVEC) were used. After HUVEC on a glass slide were incubated with IL-1beta for 4 h, cancer cells in suspension were perfused on HUVEC at wall shear stresses of 5-40 microN/cm2. Experiments were videotaped, and the number of adherent cells were counted. Additionally, the effects of anti-sialyl Lewis a (SLea) MoAb, anti-E-selectin MoAb, and a PGI2 analogue were investigated. Expression of adhesion molecules on cancer cells and HUVEC was assessed using flow cytometry and enzyme immunoassay, respectively. Few cancer cells adhered to HUVEC without IL-1beta; however, many cancer cells adhered to IL-1beta-stimulated HUVEC at low shear stress (5-20 microN/cm2). Cancer cells did not migrate beneath HUVEC. The increased adhesion was inhibited by anti-E-selectin MoAb, anti-SLea MoAb, and a PGI2 analogue. In addition, the PGI2 analogue decreased the surface expression of SLea on Colo 201 cells. These results suggest that Colo 201 cells adhere to IL-1beta-stimulated endothelial cells via SLea and E-selectin under low flow conditions; PGI2 analogues may protect against metastasis by inhibiting cancer cell-endothelial cell interactions.

Adult↗
PubMed1999

Chloroplast Cpn20 forms a tetrameric structure in Arabidopsis thaliana.

Chloroplast chaperonin 20 (Cpn20) in higher plants is a functional homologue of the Escherichia coli GroES, which is a critical regulator of chaperonin-mediated protein folding. The cDNA for a Cpn20 homologue of Arabidopsis thaliana was isolated. It was 958 bp long, encoding a protein of 253 amino acids. The protein was composed of an N-terminal chloroplast transit peptide, and the predicted mature region comprised two distinct GroES domains that showed 42% amino acid identity to each other. The isolated cDNA was constitutively expressed in transgenic tobacco. Immunogold labelling showed that Cpn20 is accumulated in chloroplasts of transgenic tobacco. A Northern blot analysis revealed that mRNA for the chloroplast Cpn20 is abundant in leaves and is increased by heat treatment. To examine the oligomeric structure of Cpn20, a histidine-tagged construct lacking the transit peptide was expressed in E. coli and purified by affinity chromatography. Gel-filtration and cross-linking analyses showed that the expressed products formed a tetramer. The expressed products could substitute for GroES to assist the refolding of citrate synthase under non-permissive conditions. The analysis on the subunit stoichiometry of the GroEL-Cpn20 complex also revealed that the functional complex is composed of a GroEL tetradecamer and a Cpn20 tetramer.

Arabidopsis↗
PubMed1999

Vacuolar processing enzyme is up-regulated in the lytic vacuoles of vegetative tissues during senescence and under various stressed conditions.

Vacuolar processing enzyme (VPE) has been shown to be responsible for maturation of various seed proteins in protein-storage vacuoles. Arabidopsis has three VPE homologues; betaVPE is specific to seeds and alphaVPE and gammaVPE are specific to vegetative organs. To investigate the activity of the vegetative VPE, we expressed the gammaVPE in a pep4 strain of the yeast Saccharomyces cerevisiae and found that gammaVPE has the ability to cleave the peptide bond at the carbonyl side of asparagine residues. An immunocytochemical analysis revealed the specific localization of the gammaVPE in the lytic vacuoles of Arabidopsis leaves that had been treated with wounding. These findings indicate that gammaVPE functions in the lytic vacuoles as the betaVPE does in the protein-storage vacuoles. The betaVPE promoter was found to direct the expression of the beta-glucuronidase reporter gene in seeds and the root tip of transgenic Arabidopsis plants. On the other hand, both the alphaVPE and gammaVPE promoters directed the expression in senescent tissues, but not in young intact tissues. The mRNA levels of both alphaVPE and gammaVPE were increased in the primary leaves during senescence in parallel with the increase of the mRNA level of a senescence-associated gene (SAG2). Treatment with wounding, ethylene and salicylic acid up-regulated the expression of alphaVPE and gammaVPE, while jasmonate slightly up-regulated the expression of gammaVPE. These gene expression patterns of the VPEs were associated with the accumulation of vacuolar proteins that are known to respond to these treatments. Taken together, the results suggest that vegetative VPE might regulate the activation of some functional proteins in the lytic vacuoles.

Amino Acid Sequence↗
PubMed1999

Ginkgo biloba leaf extract: review of biological actions and clinical applications.

The number of studies on Ginkgo biloba leaves is rapidly increasing. A variety of effects of Ginkgo biloba leaf extract (GBLE) have been identified. GBLE contains many different flavone glycosides and terpenoides. GBLE has an antioxidant action as a free radical scavenger, a relaxing effect on vascular walls, an antagonistic action on platelet-activating factor, an improving effect on blood flow or microcirculation, and a stimulating effect on neurotransmitters. Besides a direct scavenging action on active oxygen species, GBLE exerts an anti-inflammatory effect on inflammatory cells by suppressing the production of active oxygen and nitrogen species. GBLE inhibited the increase in the products of the oxidative decomposition low-density lipoprotein (LDL), reduced the cell death in various types of neuropathy, and prevented the oxidative damage to mitochondria, suggesting that GBLE exhibits beneficial effects on neuron degenerative diseases by preventing chronic oxidative damage. The study using a model of ischemia-reperfusion injury has also demonstrated the protective effect of GBLE on cardiac muscle and its antioxidative action in vivo. Favorable results have been obtained in double-blind, placebo-controlled, comparative trials of patients with memory disorders, obstructive arteriosclerosis, and dementia. We review the recent studies on GBLE with respect to its various pharmacological actions, such as a scavenging activity on free radicals and an inhibitory action on lipid peroxidation. GBLE shows a very strong scavenging action on free radicals, and is thus considered to be useful for the treatment of diseases related to the production of free radicals, such as ischemic heart disease, cerebral infarction, chronic inflammation, and aging.

Animals↗
PubMed1999

A novel water-soluble vitamin E derivative protects against experimental colitis in rats.

This study was designed to investigate the effects of water-soluble vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), on experimental colitis in rats. Colitis was induced in male Wistar rats weighing 200 grams using an enema of trinitrobenzene sulfonic acid (TNBS) dissolved in 50% ethanol; 1 ml of TMG dissolved in physiological saline (0.2 mg/ml, 2 mg/ml, 20 mg/ml) was injected intraperitoneally every day for 1 week after the enema. The damage score, wet weight of the colon, and increase in body weight were estimated 1 week after the enema of TNBS. Thiobarbituric acid-reactive substances (TBA-RS), an index of lipid peroxidation, and the level of alpha-tocopherol or TMG in the colonic mucosa were measured 1 week after the induction of colitis. As a result, increase in body weight was inhibited by the induction of colitis, although the inhibition was reduced in the group treated with TMG. The damage score, wet weight and TBA-RS were increased significantly in the colitis group; however, they were inhibited by the administration of TMG. The alpha-tocopherol level in the colonic mucosa was reduced by the induction of colitis, wheres TMG could not be detected in the colonic mucosa of rats treated with TMG. These results suggest that TMG is effective for the treatment of colitis in rats induced by TNBS.

Animals↗
PubMed1999

Structure-function relationship of model Aib-containing peptides as ion transfer intermembrane templates.

Peptaibols comprise a family of peptide antibiotics with high contents of 2-aminoisobutyric acid (Aib) residues and C-terminal amino alcohols. These peptides form alpha-helical structures leading to voltage-gated ion channels in lipid membranes. In the present study, amphiphilic helical Aib-containing peptides of various chain-lengths, Ac-(Aib-Lys-Aib-Ala)n-NH2 (n = 1-5), were designed to investigate the mechanisms of the aggregation and transmembrane orientation of helical motifs in lipid bilayer membranes. Peptide synthesis was performed by the conventional stepwise Fmoc solid-phase method. The crude peptides were obtained in high yields (66-85%) with high purities (69-95%). Conformational analysis of the synthetic peptides was performed by CD spectroscopy. It was found that these peptides take on highly helical structures, and the helicity of the peptides increases with an increase in chain-length. The longest peptide, Ac-(Aib-Lys-Aib-Ala)5-NH2, self-aggregates and adopts a barrel-stave conformation in liposomes. Ac-(Aib-Lys-Aib-Ala)5-NH2 exhibited potent antimicrobial activity against Gram-positive bacteria. Patch-clamp measurements revealed that this peptide can form well-defined ion channels with a long lifetime at relatively low transbilayer potentials and peptide concentrations. For this peptide, the single-channel conductance of the most frequent event is 227 pS, which could be related to a single-state tetrameric pore.

Amino Acid Sequence↗
PubMed1999

Accumulation of a fusion protein containing 2S albumin induces novel vesicles in vegetative cells of Arabidopsis.

We have previously reported that precursor-accumulating (PAC) vesicles found exclusively in developing seeds are involved in a transport of seed storage proteins, such as 2S albumin, from the endoplasmic reticulum to protein-storage vacuoles. Here, we constructed chimeric genes that encode fusion proteins consisting of both various lengths of polypeptides derived from pumpkin 2S albumin and a selectable marker enzyme, phosphinothricin acetyltransferase. The chimeric genes were expressed in transgenic Arabidopsis in order to investigate the mechanism of the PAC vesicle formation. A fusion protein expressed by one of the chimeric genes is accumulated as a proprotein-precursor form, and localized in novel vesicles of vegetative cells. The vesicles show distinct features that well much to the PAC vesicles. Despite of the accumulation of the fusion protein, the transgenic Arabidopsis is still sensitive to phosphinothricin. Phosphinothricin acetyltransferase contained in the fusion protein is obviously compartmentalized in the PAC-like vesicles that do not permit the detoxification of this herbicide. These results indicate that the PAC-like vesicle can be induced in vegetative cells by the ectopic expression of the protein that is destined to be compartmentalized into the PAC vesicles.

Acetyltransferases↗
PubMed1999

Early monocytopenia after chemotherapy as a risk factor for neutropenia.

Neutropenia is a major adverse effect of cancer chemotherapy and sometimes causes life-threatening events. The present study was therefore conducted to identify risk factors for such neutropenia. Forty patients who had received chemotherapy at 3- or 4-week intervals for advanced lung cancer from May 1991 through February 1997 were analyzed retrospectively. Thirty-seven of the patients had received cisplatin-based chemotherapy. The mean neutrophil count on days 6 to 8 in 32 patients who developed grade 3 or 4 neutropenia during chemotherapy was not significantly different from that in eight patients who developed grade 1 or 2 neutropenia during chemotherapy. However, the mean leukocyte and monocyte counts on days 6 to 8 in the 32 patients with grade 3 or 4 neutropenia (5,181 +/- 1,830/microl and 87 +/- 84/microl, respectively) were significantly lower than those in the eight patients with grade 1 or 2 neutropenia (7175 +/- 1671/microl and 248 +/- 127/microl, respectively; p = 0.008 and p = 0.0001). Moreover, all 30 patients with a monocyte count of less than 150/microl on days 6 to 8 had grade 3 or 4 neutropenia and 8 of 10 patients with a monocyte count of 150/microl or higher on days 6 to 8 had grade 1 or 2 neutropenia, despite the absence of a correlation between the leukocyte count on days 6 to 8 and the neutrophil nadir. We conclude that a monocyte count of less than 150/microl on days 6 to 8 may be a predictor of grade 3 or 4 neutropenia during cancer chemotherapy at 3- or 4-week intervals (sensitivity 94%, specificity 100%).

Adult↗
PubMed1999

Fluorescein angiography of extreme peripheral retina and rubeosis iridis in proliferative diabetic retinopathy.

PURPOSE: To study the fluorescein angiographic appearance of the extreme peripheral retina in patients with proliferative diabetic retinopathy with rubeosis iridis. METHODS: Using a modified endoscope, fluorescein angiography was performed prospectively during pars plana vitrectomy on 14 eyes of 12 patients with proliferative diabetic retinopathy who had or developed postoperative rubeosis. These findings were compared with those obtained from 41 eyes of 35 patients without rubeosis. RESULTS: A fibrovascular ridge was observed at the ora serrata in 11 of 12 eyes (92%) with rubeosis but in only 15 of 35 (43%) eyes without rubeosis. Seven of 12 (58%) eyes with rubeosis showed the continuous type of fibrovascular ridge, whereas only 5 of 35 (14%) eyes without rubeosis showed the continuous type. A broom-shaped continuous fibrovascular ridge was observed only in eyes with rubeosis. CONCLUSIONS: Many eyes with proliferative diabetic retinopathy showed unusual findings in the extreme retinal periphery, which were more frequent in the eyes with rubeosis iridis. Fluorescein angiography of this region may provide valuable information for possible anterior neovascularization.

Adult↗
PubMed1999

[Kinetic analysis of anti-HIV titer in early stage of HIV infection--a new testing strategy to differentiate early HIV infection individuals from false positive cases].

We analyzed the anti-HIV antibody titer by particle agglutination (PA) on 11 HIV seroconversion panels. PA titer increased very rapidly and the titer went up to 1,000 or more within 18.2 days after seroconversion. The results suggest that one to two weeks of duration will be enough to differentiate persons at the early stage of HIV infection from individuals with HIV screening test initially reactive but false positive. In Japan, HIV prevalence is very low and the majority of the HIV screening test-positive (reactive) cases turned out to be false positive. This HIV testing strategy (one to two weeks interval bleeding) will be very practical and useful to differentiate early stage of HIV infection cases from the majority of false positive cases.

False Positive Reactions↗
PubMed1999

[Evaluation of a new screening assay kit for the combined detection of HIV p24 antigen and antibody--comparison of the performance of the new kit and HIV antibody assay kits].

DUO is an automated HIV infection screening test kit based on the combined detection of p24 Ag and anti-HIV-1 and anti-HIV-2 IgG in human sera or plasma using the ELFA technique (Enzyme-Linked Fluorescent Assay). The performance of DUO was compared with that of HIV-1/HIV-2 3rd generation EIA plus and particle agglutination (PA) test. A total of 141 seropositive sera, 3 seroconversion panels, 300 seronegative sera and 387 potentially cross-reactive serum samples were tested. One hundred and forty one seropositive sera in Japan and Cameroon were all positive with DUO. Three seroconversion panels (panel Q, Z, AE) were tested to evaluate sensitivity. In Panel Q, infecution was detected seven days earlier with DUO than with the 3rd generation EIA plus and PA. In Panel AE, infection was detected four days earlier with DUO than with the single antibody assays. Three hundred seronegative sera from Kanagawa prefectural public health centers were all negative with DUO as well as PA test. Three hundred and eighty seven potentially cross-reacting samples were tested to challenge the specificity of the assay. These included samples from pregnant women and hepatitis patients. In four of the 204 samples from pregnant women, false-positive results were observed with DUO. In three of the 183 samples from hepatitis patients, false-positive results were also obtained with DUO. All samples of 7 DUO positive results were negative with western blot test. Five of them were negative with RT-PCR and 2 of them were not tested because there were not enough samples. Thirty cross-reacting (false-positive) samples by PA test from blood donors were tested by DUO, and all of these were negative by DUO.

AIDS Serodiagnosis↗
PubMed1999

Effect of azelastine on platelet-activating factor-induced microvascular leakage in rat airways.

To determine the effect of the antiallergic drug azelastine on airway mucosal inflammation, we studied airway microvascular permeability in response to platelet-activating factor (PAF) in pathogen-free rats. Vascular permeability and neutrophil accumulation were assessed by the percent area occupied by Monastral blue-labeled blood vessels and by myeloperoxidase-containing granulocytes, respectively, in whole mounts of the trachea and main bronchus. Intravenous PAF caused dose-dependent increases in the area density of Monastral blue-labeled vessels and neutrophil influx, and the former effect was inhibited by depletion of circulating neutrophils by cyclophosphamide or treatment with the neutrophil elastase inhibitor ONO-5046. Pretreatment with azelastine inhibited PAF-induced vascular leakage without affecting neutrophil accumulation. This inhibitory effect of azelastine was not seen in neutropenic rats and ONO-5046-treated rats. PAF increased neutrophil elastase contents in bronchoalveolar lavage fluid, an effect that was inhibited by azelastine. Therefore, azelastine attenuates PAF-induced airway mucosal microvascular leakage, probably involving inhibition of the release of neutrophil elastase from activated neutrophils.

Animals↗