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Biomedical subjects

H Kurihara

Publications and source records attributed to H Kurihara.

At least 289 records · Page 16Linked to original sources
PubMed1992

The additive effect of alpha-difluoromethylornithine (DFMO) and radiation therapy on a rat glioma model.

The effects of alpha-difluoromethylornithine (DFMO), radiation and the therapy of their combination were investigated in rats bearing G-XII glioma. DFMO treatment as well as radiation therapy prolonged the survival period when compared to the results in non-treated control rats. The combination therapy showed a greater effect on the survival rate than the single therapies, the effect being additive. The concentration of putrescine, spermidine, and N1-acetylspermidine in tumor tissue was lowered by DFMO, while that of spermine was slightly elevated. Radiation decreased the concentration of all the polyamines, putrescine, spermidine, spermine and N1-acetylspermidine. The concomitant treatment with DFMO and radiation further decreased the concentrations of putrescine and N1-acetylspermidine in tumor tissues. The survival period of glioma-bearing rats is inversely correlated with the tissue levels of putrescine plus N1-acetylspermidine.

Animals↗
PubMed1992

Interleukin-8 is a major neutrophil chemotactic factor derived from cultured human gingival fibroblasts stimulated with interleukin-1 beta or tumor necrosis factor alpha.

Inflammatory mediators produced by cells in the gingiva have been implicated in the initiation and progression of periodontal disease, a common infectious disease. In this study, we examined the biological activity of neutrophil chemotactic factors and the kinetics of expression of interleukin-8 (IL-8) mRNA derived from normal gingival fibroblasts in response to inflammatory mediators in an in vitro model. Gingival fibroblasts stimulated by either recombinant human interleukin-1 beta or recombinant human tumor necrosis factor alpha produced neutrophil chemotactic factors after 4 h, whereas expression of cell-derived IL-8 mRNA was detected within 1 h after stimulation. Furthermore, in a neutralization assay, rabbit anti-recombinant human IL-8 antiserum inhibited neutrophil chemotactic activity to basal levels. These results provide evidence that gingival fibroblasts synthesize potent chemotactic factors such as IL-8 in the presence of the inflammatory mediators interleukin-1 beta and tumor necrosis factor alpha. The activity of these factors may contribute to neutrophil-mediated processes in the pathogenesis of periodontal disease.

Cells, Cultured↗
PubMed1992

Production of endothelin-1 in vascular endothelial cells is regulated by factors associated with vascular injury.

We studied the effects of factors associated with vascular injury on the production of endothelin-1 (ET-1) in cultured porcine aortic endothelial cells. ET-1 mRNA expression and peptide production in endothelial cells were increased by thrombin, transforming growth factor beta 1 (TGF beta 1), interleukin-1 (IL-1) and tumor necrotizing factor alpha (TNF alpha). The analysis of the enhancer/promoter region of the human ET-1 gene showed that the ET-1 gene transcription is regulated in a cell-specific manner and is activated by thrombin, TGF beta 1 and IL-1. These results suggest that the production of ET-1 in endothelial cells is regulated by factors associated with platelet aggregation, macrophage infiltration and the formation of atherosclerotic lesions.

Animals↗
PubMed1992

[Reproductive and developmental toxicity studies of FUT-187. (V)--Perinatal and postnatal study in rats with oral administration of FUT-187].

FUT-187 was given orally at 20, 120 and 720 mg/kg to female rats during the perinatal and postnatal periods and the effect on dams and offspring were evaluated. One dam during the terminal period of gestation and 3 dams after delivery in the 720 mg/kg group died due to FUT-187. In dams, an increased pancreas weight in the 20 mg/kg or more groups, temporary salivation after dosing in the 120 mg/kg or more groups, and a depression of body weight gain and decreased food intake and weight of the carcass in the 720 mg/kg group were statistically significant in comparison with controls. In offspring, postnatal death rate in the 720 mg/kg group tended to increased. Decreased body weight gain and delayed appearance of abdominal hair and descent of testis in the 720 mg/kg group were statistically significant in comparison with controls. There were no treatment-related abnormalities in visceral examination, organ weight, skeletal examination, sensory function, behavioral function, learning ability or reproductive function. Based on these results, it is concluded that the no-effect-dose levels of FUT-187 are less than 20 mg/kg for dams, and 120 mg/kg for reproductive performance of dams and offspring development.

Abnormalities, Drug-Induced↗
PubMed1992

The altered glomerular filtration slits seen in puromycin aminonucleoside nephrosis and protamine sulfate-treated rats contain the tight junction protein ZO-1.

Nephrosis induced in rats by puromycin aminonucleoside treatment (PAN) results in the apical displacement of the glomerular filtration slit membrane by newly formed, intercellular occluding-type junctions. Similar changes can also be induced by acute kidney perfusion with protamine sulfate (PS). We have investigated the molecular nature of these altered junctions using an antibody to ZO-1, a protein found exclusively in tight junctions. Immunoblotting demonstrates ZO-1, a 225-kd band, in glomerular extracts of normal, PAN-, and PS-treated rats. By immunofluorescence, ZO-1 was localized at the base of podocytes outlining the capillary loops of glomeruli from all three experimental groups. At the electron microscope level, using immunoperoxidase or immunogold labeling, ZO-1 was concentrated along the cytoplasmic surfaces of the slit diaphragms of normal rats. In PAN or PS rats, it was concentrated along both the newly formed occluding-type junctions and the remaining slit diaphragms. When podocalyxin (the major membrane sialoprotein of the podocyte) was similarly localized, it was found exclusively apical to the displaced slit membrane. Based on morphology and the presence of ZO-1, the altered junctions seen in PAN and PS rats appear to represent bona fide tight junctions. Their rapid (15-minute) induction in PS-treated rats suggests that on neutralization of the cell surface charge by polycation perfusion, discontinuous tight junctions form from a preexisting pool of junctional proteins. These findings raise the possibility that glomerular hydraulic conductivity may be regulated in part by regulating the relative patency and width of the filtration slits through focal tight junction assembly.

Animals↗
PubMed1991

Monoclonal antibody to a specific antigen from Wolinella recta ATCC 33238.

Four monoclonal antibodies (m-Abs) to a specific antigen (150-kDa protein antigen) isolated from Wolinella recta ATCC 33238 by acid extraction were obtained. The four antibodies were all of the IgG1 subclass and exhibited equally high specificity for the antigen. A battery of 14 strains or oral bacteria were screened for cross-reactivity with each mAb by ELISA and Western blot analysis. Weak cross-reactivity to some strains was observed which differed depending upon the mAb. Immuno-electromicroscopic studies were performed with a mAb which revealed that the 150-kDa antigen was localized to the cell surface of W. recta ATCC 33238.

Animals↗
PubMed1991

Intracellular localization of group II phospholipase A2 in rat vascular smooth muscle cells and its possible relationship to eicosanoid formation.

We investigated the localization of group II phospholipase A2 (PLA2-II) in rat vascular smooth muscle cells (VSMCs) by applying immunofluorescence and immunoelectron microscopy with its polyclonal antibody. In unstimulated cells, no immunolabelling was detected in the cells. On the other hand, in the cells stimulated with tumor necrosis factor (TNF) and/or forskolin (FK), intense fluorescence was detected in the cytoplasm. The immunoperoxidase reactions were detected in the cisternae of rough endoplasmic reticulum (rER), trans-cisternae of Golgi apparatus, and small vesicles beneath the plasma membrane. Western blot analysis showed VSMCs secrete PLA2-II after stimulation. Secreted PLA2-II was associated with the plasma membrane and extracellular matrix. Colchicine inhibited PLA2-II synthesis and its secretion to the extracellular space. These observations indicate that in VSMCs PLA2-II is synthesized at rER. transported to Golgi apparatus, discharged into extracellular space via the small vesicles, and microtubules may concern with its process. Furthermore, in VSMCs treated with TNF or TNF + FK, prostaglandin E2 formation was also increased. Actinomycin D and cycloheximide inhibited the potentiation of the prostaglandin E2 formation induced by TNF or TNF + FK, indicating that both RNA and protein synthesis are required for the potentiation. These results suggest an involvement of PLA2-II in the prostaglandin formation.

Animals↗
PubMed1991

Isolation and partial characterization of a 39 kDa major outer membrane protein of Actinobacillus actinomycetemcomitans Y4.

The outer membrane fractions of Actinobacillus actinomycetemcomitans, which were extracted from whole cells with cetyl trimethyl ammonium bromide and CaCl2, contained four major outer membrane proteins (MOMP) of 39, 37, 36 and 30 kDa. The 39 kDa MOMP of A. actinomycetemcomitans was sequentially purified by extraction with Zwittergent 3-14 detergent, anion-exchange chromatography and gel filtration chromatography. Analysis of amino acid composition and N-terminal amino acid sequence of 20 residues of purified 39 kDa MOMP was performed. Although some of the periodontitis patient sera reacted strongly with 39 kDa and 30 kDa MOMP in crude outer membrane fractions, purified 39 kDa MOMP showed decreased immunoreactivity with the human sera.

Actinobacillus↗
PubMed1991

Molecular cloning and sequence analysis of antigen gene tdpA of Treponema denticola.

We isolated and characterized an immunogenic protein of an oral spirochete, Treponema denticola Johnson. A genomic DNA library constructed with bacteriophage lambda EMBL3 as a vector was immunologically screened with a rabbit antiserum against the whole cells. Using Western immunoblot analysis, we found a particular clone encoding an antigen with a molecular weight of 53,000; we designated the antigen as T. denticola protein A (TdpA). Complete sequence determination revealed an open reading frame of 1,419 bp and a signal peptide sequence that was homologous to that of bacterial lipoprotein. Southern hybridization analysis revealed that the tdpA gene is highly conserved in six tested strains of T. denticola species. Furthermore, we found that sera from some periodontitis patients contained antibody against the TdpA protein, although the reactivities of the antibodies varied among individuals.

Amino Acid Sequence↗
PubMed1991

Humoral immune response to an antigen from Porphyromonas gingivalis 381 in periodontal disease.

The humoral immune responses of patients with periodontitis were evaluated to characterize the host response to Porphyromonas gingivalis. A sonic extract of P. gingivalis 381 from whole cells was fractionated by gel chromatography and ion-exchange chromatography. The fractionated extracts were evaluated by Western blot (immunoblot) analyses with patient sera. A dominant antigen was identified from the sonic extract with an apparent molecular mass of 53 kDa. The 53-kDa protein antigen (Ag53) was purified by affinity chromatography by using a monoclonal antibody. Ag53 was detected on the vesicle surface of P. gingivalis 381 by immunoelectron microscopy by using the monoclonal antibody and was detected as a major protein in the outer membrane and in vesicles by Western blot analysis. Monoclonal antibody cross-reactivity to Ag53 in the sonic extracts of P. gingivalis ATCC 33277, P. gingivalis 1021, and Porphyromonas endodontalis ATCC 35406 was revealed. Seventy-seven patients with periodontitis were examined for their responses to Ag53. Serum immunoglobulin G (IgG) from 54 patients reacted strongly to Ag53; however, serum IgG from the remaining 23 patients did not exhibit detectable reactivity at all to Ag53, even though the patients had high serum IgG titers to the sonic extract. Ag53 is a new marker that represents an interesting aspect of the humoral immune response to P. gingivalis in patients with periodontitis.

Antibodies, Bacterial↗
PubMed1991

Erythrocyte carbonic anhydrase I concentration in patients receiving thyroxine.

We recently reported that the red blood cell (RBC) carbonic anhydrase I (CAI) concentration in patients with hyperthyroidism is reduced and reflects the patient's mean thyroid hormone level over the preceding months. In this study, RBC CAI concentrations were measured in patients with thyroid nodules who were receiving suppressive doses of thyroxine (group I) and compared with those obtained in patients with primary hypothyroidism receiving replacement doses of thyroxine (group 2). Of the 17 patients in group 1, 16 (94%) had elevated plasma free T4 levels, but all 17 had normal free T3 levels. Of the 17 patients in group 2, 16 (94%) had normal free T4 levels and all 17 had normal free T3 levels. Plasma TSH concentrations in group 1 were all below the lower limit of sensitivity of 0.04 mU/l. In group 2, 11 had normal and 6 had slightly elevated plasma TSH concentrations. The mean (+/- SD) RBC CAI concentration in group 1 (300 +/- 53 nmol/g Hb) was significantly lower than that in group 2 (340 +/- 57 nmol/g Hb). The RBC CAI concentration was significantly correlated with both the concentration of plasma free T4 and free T3. These observations indicate that in patients receiving suppressive doses of thyroxine a slight increase in the plasma free T4 concentration produces a slight but significant decrease in RBC CAI levels.

Adult↗
PubMed1990

Mucoepidermoid carcinoma of the thyroid gland.

An extremely rare case of mucoepidermoid carcinoma of the thyroid in a 56-year-old woman is presented. The patient clinically having Hashimoto's thyroiditis was noted a nodule in her neck. The tumor was sited in the midportion of the left lobe of the thyroid, and histologically it showed both squamous features and mucin production. The squamous cells were arranged in solid sheets with horny pearls and the mucous cells tended to line dilated duct-like elements. Ultrastructurally, the epidermoid cells had aggregates of tonofilaments and well-developed desmosomal attachments, and the mucous cells contained numerous mucin granules in their cytoplasm. Immunohistochemical studies revealed that cytokeratin antibodies showed positivity for both the lining cells and squamous cells, whereas carcinoembryonic antigen positivity was found in the lining cells and intraluminal material. The tumor cells were negative for thyroglobulin, calcitonin, vimentin, chromogranin, and neuron-specific enolase. These unusual histologic and immunohistochemical features are suggestive of a tumor related to the so-called "solid cell nest" of the thyroid.

Carcinoembryonic Antigen↗
PubMed1990

Cerebral microvessel endothelium is producing endothelin.

Endothelin, a potent vasoconstrictor peptide, was recently isolated from the supernatant of the cultured endothelia of the porcine aorta and is now supposed to be the most likely candidate for the endothelium-derived contractile factor (EDCF), which is responsible for the endothelium-dependent vasoconstriction by various stimuli. In this study, the production of endothelin by the endothelia of porcine cerebral microvessels was revealed by the Northern blot analysis with porcine endothelin cDNA probe and the enzyme-linked immunosorbent assay (ELISA) with anti-porcine endothelin antibody. Our results raise the possibility that the endothelia of cerebral microvessels regulate the local blood flow within the brain through the production of endothelin.

Animals↗
PubMed1990

Interleukin 1 increases the production of endothelin-1 by cultured endothelial cells.

We examined the effect of human recombinant interleukin 1 (IL-1) on the production of endothelin-1 by cultured porcine endothelial cells. The induction of endothelin-1 mRNA began within 1 hr of exposure to IL-1, showed twin peaks at 4 and 24 hr, and declined thereafter. Enzyme-linked immunosorbent assay revealed that the amount of endothelin-1 peptide in conditioned media was also increased by IL-1 in a dose- and time-dependent manner. Our results suggested that IL-1, a macrophage-derived cytokine, may affect the contraction and proliferation of vascular smooth muscle cells by stimulating the production of endothelin by endothelial cells.

Animals↗
PubMed1990

Distribution of microtubules and microfilaments in thyroid follicular epithelial cells of normal, TSH-treated, aged, and hypophysectomized rats.

We investigated the distribution of microtubules and microfilaments in rat thyroid follicular epithelial cells by applying an immunofluorescence technique with monoclonal antibodies against tubulin and by staining sections with rhodamine-phalloidin. In normal thyroid cells, microtubules run longitudinally from the apical region to the basal region intersecting with each other. In addition, intense labelling with tubulin antibodies was observed in the apical part of the cell. The ultrastructural examinations showed that microtubules often run along the apical plasma membrane. Dot-like labelling with anti-tubulin antibodies was often observed in the perinuclear space, but not microtubules were recognized in the nucleus. Microfilaments bound to rhodamine-phalloidin were distributed mainly beneath the apical plasma membrane, and the portion along the basolateral membrane was scarcely positive. The apical pole of the follicle cell was also decorated by anti-microtubule-associated protein-2 (MAP-2). After TSH stimulation, the intensity of immunocytochemical staining against tubulin was remarkably increased in the cytoplasm. Simultaneously, at the apical region, the staining intensity of rhodamine-phalloidin was increased. Microtubules and microfilaments appeared in the pseudopods after TSH injection. In hypophysectomized or aged rats, thyroid follicular epithelial cells decreased in height, and both immunofluorescent labelling against tubulin and rhodamine-phalloidin labelling were markedly decreased. These results indicate that the distribution and polymerization of microtubules and microfilaments in thyroid follicular epithelial cells vary with the functional stage.

Actin Cytoskeleton↗