Biomedical subjects

H Asada

Publications and source records attributed to H Asada.

At least 91 records · Page 5Linked to original sources

PubMed1996

Murine epidermal Langerhans cells do not express the low-affinity receptor for immunoglobulin E, FcEpsilonRII (CD23).

The low-affinity receptor for IgE, FcepsilonRII (CD 23), plays an important role in IgE-mediated disorders such as allergy, atopy, and parasitic infections. In humans, the FcepsilonRII B isoform on epidermal Langerhans cells is thought to be an important accessory molecule in the allergy-specific T cell activation in atopic dermatitis. Since considerable knowledge about the accessory function of Langerhans cells for T-cell activation stems from mouse models, and since an IgE-bearing Langerhans cell mouse model would be useful in studying the pathophysiology of atopic dermatitis, we determined whether FcepsilonRII was also present on murine Langerhans cells. FcepsilonRIIa, which is the major FcepsilonRII isoform in mice, was found to be constitutively expressed on spleen cells from normal mice but was not present on epidermal Langerhans cells. When interleukin-4, a known inducer of FcepsilonRII, was administered in vivo, FcepsilonRII-specific mRNA and protein was significantly unregulated in spleen cells but not in Langerhans cells. De novo synthesis of FcepsilonRII was also induced in vitro by interleukin-4 on spleen cells, but not on epidermal cells. The presence of a recently cloned murine counterpart of the human Fc-epsilon- R. II isoform on murine Langerhans cells could also be excluded on the protein and mRNA level because of the high degree of homology to mouse Fc-epsilon-R IIA. Taken together the data indicate that murine epidermal Langerhans cells do not express the low-affinity receptor for IgE.

Animals↗

PubMed1996

Successful treatment of molluscum contagiosum in the immunosuppressed adult with topical injection of streptococcal preparation OK-432.

A 37-year-old Japanese woman received an anticancer drug for 5 years following resection of mammary cancer and then developed widespread mollusca contagiosa, which we considered to be caused by immunosuppression induced by the chemotherapy. Because OK-432 (penicillin-treated and heat-treated lyophilized powder by a substrain of Streptococcus pyogenes A) was expected to be effective for immunosuppression, we tried its topical injection. The skin lesions disappeared almost completely within three months. OK-432 therapy is considered hopeful for treating viral skin diseases, even in immunosuppressed patients.

Adult↗

PubMed1996

[A case report of a bronchogenic cyst of the diaphragm causing rupturing into the left pleural cavity].

A rare case of a bronchogenic cyst of the diaphragm was reported. The patient was a 56-year-old woman complaining of epigastric pain. A CT scan and a MRI examination revealed a cystic tumor at the left vertebro-phrenic angle. The cyst ruptured into the left pleural cavity causing chest pain and consequently reducing its size. As the cyst had enlarged again after 6 months, she received surgical treatment and the tumor was totally removed. The cyst was monolocular, originating from the diaphragm and proved to be bronchogenic cyst. It had bronchial epithelium, smooth muscle, bronchial gland and cartilage histologically. Japanese literature on the bronchogenic cysts of the diaphragm were discussed. Seven cases, including this case, of bronchogenic cysts of the diaphragm have been reported in Japan. It is rare for bronchogenic cysts to rupture into the pleural cavity.

Bronchogenic Cyst↗

PubMed1996

[A study on anticoagulation for cardiovascular diseases using international normalized ratio (INR)].

The usefulness of INR as an index for assessing anticoagulation was studied using 85 outpatients, all suffering cardiovascular diseases and receiving warfain as subjects. The thrombotest, prothrombin time and INR were measured at follow-up, monthly intervals. The correlation between the thrombotest value and the INR value were assessed retrospectively. We found a stronged correlation between them. The 10 approximately 25% range of the thrombotest value, the therapeutic range, corresponded to 2.29 approximately 3.60 of the INR value. The INR value was more accurate than the thrombotest valve in the situation of prolonged coagulation time. It is recommended to use INR as an objective index for the anticoagulation due to increase accuracy and objectivity when comparing the data among the various institutions.

Anticoagulants↗

PubMed1995

Long-term depletion of brain histamine induced by alpha-fluoromethylhistidine increases feeding-associated locomotor activity in mice with a modulation of brain amino acid levels.

We examined the long-term effects of administration of (S)-alpha-fluoromethylhistidine (FMH), a specific inhibitor of histidine decarboxylase, on the spontaneous locomotor activity, food intake and brain contents of histamine, catecholamines, serotonin and amino acids of ICR mice. The distance of ambulation and number of rearings significantly increased from 8 to 15 h (20.00-03.00 h) after treatment with FMH (100 mg/kg, i.p.) and the 24-h food intake also increased significantly. On FMH treatment, the locomotor activity in movements of 3-15 cm/0.5 s was greater than that of control mice, whereas the number of slight movements (0-1 cm/0.5 s) decreased, suggesting that once a mouse treated with FMH is in motion, it moves a longer distance than a control mouse. We sacrificed mice 12 or 24 h after FMH treatment to measure the brain contents of histamine, monoamines and amino acids. Decrease of the brain histamine content to 35% of the control level was observed until 24 h after FMH treatment, but no significant changes in the brain catecholamine and serotonin contents were detected. However, the brain GABA content of ICR mice decreased to 85% of control 12 h after FMH treatment. Moreover, decrease of the brain GABA content after FMH treatment was greater in mast cell-deficient W/Wv mice, being 70 and 62% of the control level 12 and 24 h after treatment, respectively. The present experiments support the idea that the locomotor activity is affected by the central histaminergic system, directly and/or indirectly.

Amino Acids↗

PubMed1995

Effect of a neuron-specific actin-binding protein, drebrin A, on cell-substratum adhesion.

Drebrin A expression was induced in non-neuronal L cells via transfection with a vector containing the cDNA of rat drebrin A. Following treatment with colcemid (5 micrograms/ml) and cytochalasin D (0.5 micrograms/ml), most L cells collapsed into round cells, while drebrin expressing cells were resistant to the treatment, keeping their cell shapes. Simultaneously, actin filaments and microtubules were disrupted in both cell lines. By quantitative analysis, in the presence of cytochalasin D, the extent of cell spreading and cell attachment in drebrin expressing cells was significantly higher than that in control cells. These results suggest that drebrin A modulates cell-substratum adhesion.

Actins↗

PubMed1995

Secretion of Alzheimer beta/A4 protein (1-40) and intracellular retention of beta/A4 protein (1-42) in transfected COS cells.

The amyloid beta/A4 protein (beta/A4) of Alzheimer disease is heterogeneous. A beta 1-40 (Asp1 to Val40) is rather soluble, whereas A beta 1-42 (Asp1 to Ala42) is more insoluble and can be the seed of deposition of A beta 1-40. Although beta/A4 itself could not be expressed transiently in COS cells by cDNA transfection, it was expressed after directly adding a signal sequence to its N-terminal end. The expressed A beta 1-40 was secreted, whereas A beta 1-42 was hardly secreted. A beta 1-40 secretion was not inhibited by metabolic inhibitors such as brefeldin A. The normally produced A beta 1-40 could not be retained intracellularly, whereas the abnormally generated A beta 1-42 might be accumulated intracellularly, resulting in cellular toxicity.

Amino Acid Sequence↗

PubMed1995

Time course of ciliary neurotrophic factor mRNA expression is coincident with the presence of protoplasmic astrocytes in traumatized rat striatum.

Adrenal grafting for Parkinson's disease has led to modest functional improvement despite poor graft survival. One explanation is a neurotrophic response within the traumatized striatum. This study was undertaken to investigate the time course of the astrocytic response in vivo and in vitro, and the expression of ciliary neurotrophic factor (CNTF) mRNA following striatal injury. Unilateral stereotaxic biopsy of the rat striatum was performed and gelatin sponge (gel-foam) was immediately placed into the biopsy cavity. Rats were sacrificed on days 1, 3, 5, 7, 14, and 28 post biopsy. Immunohistochemical staining of the traumatized striatum with antibodies to glial fibrillary acidic protein (GFAP) was carried out. The reactive astrocytes which appeared within 7 days after trauma were mostly protoplasmic on the basis of morphology, and maximal on day 7, being 30 times the level in the normal striatum. After day 7, fibrous astrocytes appeared and increased up to day 28, while protoplasmic astrocytes decreased. In addition, immunocytochemical double staining of short term cultured astrocytes from the traumatized striatum with anti-A2B5 and anti-GFAP antibodies revealed that 84% and 90% of astrocytes were type 1 astrocytes on days 3 and 7, respectively; however, by day 28 47% of astrocytes were type 2. Northern blot analysis revealed that CNTF mRNA expression was up-regulated and peaked on day 7, coincident with a predominance of protoplasmic astrocytes in vivo and type 1 astrocytes in vitro, respectively. These findings suggest that the expression of CNTF mRNA is part of the early astrocytic response to trauma, particularly associated with protoplasmic astrocytes in vivo and type 1 astrocytes in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Long-term production of neurotrophic factors by astrocyte cultures from hemiparkinsonian rat brain.

Transplantation of dopaminergic or neurotrophic tissues is an experimental treatment of Parkinson's Disease. However, in animal models sustained recovery may occur after surgical trauma to affected brain areas even in the absence of grafted tissue. Consequently, brain tissue reacting to local trauma in these experiments must be capable of substantial neurotrophic responses. To evaluate the potential of astrocytes in these neurotrophic responses, cultures were obtained from gelatin implants into striatal cavities that were created in hemiparkinsonian rats. The type 1 astrocyte phenotype as determined immunocytochemically was maximal at day 7 in vitro and paralleled the glial reaction in the adjacent brain parenchyma. Neurite-promoting activity of the culture medium was determined in a chick dorsal root ganglion bioassay and also was established by 7 days. Nerve growth factor antibodies neutralized only around 40% of this activity. Neurotrophic activity was absent with assay of media from early or long-term newborn rat astrocytes, and of medium conditioned by a monoyte/macrophage cell line. Passage after several months yielded astrocyte cultures that repeated a surge of neurite-promoting activity. This long-term potential to produce multiple neurotrophic factors indicates that autologous astrocytes in affected brain regions may serve either as targets for or agents of therapy of Parkinsonism.

Animals↗

PubMed1995

Absorption characteristics of chemically modified-insulin derivatives with various fatty acids in the small and large intestine.

Absorption characteristics of insulin derivatives chemically modified with various fatty acids in the intestine were determined by in situ loop and in vitro modified Ussing chamber methods. The pharmacological activities of these acyl derivatives, as assessed by their hypoglycemic effects after intravenous administration, were reduced upon increasing the carbon number of the fatty acid(s) chemically attached to native insulin. However, high pharmacological activities were seen when mono-and dicaproyl derivatives were administered intravenously. The absorption of insulin after its small intestinal administration could be hardly improved by acylation. In contrast, its absorption after the large intestinal administration was increased by increasing the number of caproic acid molecules attached to insulin. Furthermore, by an in vitro modified Ussing chamber method, it was revealed that the permeability of insulin across both the duodenal and colonic mucous membranes was also improved by increasing the number of caproic acid molecules. These in situ and in vitro results indicated that the chemical modification of insulin with fatty acids was a useful approach for improving insulin absorption from the large intestine.

Animals↗

PubMed1995

Gene cloning, purification, and characterization of thermostable and halophilic leucine dehydrogenase from a halophilic thermophile, Bacillus licheniformis TSN9.

A halophilic and thermophilic isolate from the sand of Tottori Dune was found to produce a thermostable and halophilic leucine dehydrogenase (EC 1.4.1.9). It was identified to be a new strain of Bacillus licheniformis. The enzyme gene was cloned into Escherichia coli JM109 with a vector plasmid pUC18. The enzyme was purified to homogeneity from the clone cell extract by ion-exchange column chromatography with a yield of 31%. The enzyme was found to be composed of eight subunits identical in relative molecular mass (43,000). The amino acid sequence of the enzyme, deduced from the nucleotide sequence of the gene, showed an identity of 84.6% with that of the B. stearothermophilus enzyme [Nagata S, Tanizawa K, Esaki N, Sakamoto Y, Oshima T, Tanaka H, Soda K (1988) Biochemistry 27:9056-9062], although both enzymes were similar to each other in various enzymological properties such as thermostability, substrate and coenzyme specificities, and stereospecificity for hydrogen transfer from the C-4 of NADH. However, they were markedly distinct from each other in halophilicity; the B. licheniformis enzyme was much more stable than the other in the presence of high concentrations of salts.

Amino Acid Oxidoreductases↗

PubMed1995

Possible role of osteopontin in deposition of calcium phosphate in human pilomatricomas.

Human pilomatricomas are benign epidermal appendage tumors composed of hair matrix-like basaloid cells and keratinized remnant cells referred to as shadow cells. Deposition of calcium phosphate usually occurs in the shadow cell nests. Because osteopontin is believed to be involved in the deposition of calcium phosphate in bones, we asked whether osteopontin messenger RNA also is expressed in pilomatricomas. Using Northern blotting and in situ hybridization we detected osteopontin messenger RNA in pilomatricoma tissues but not in normal skin tissue. By the combination of in situ hybridization and immunohistochemistry, osteopontin messenger RNA-expressing cells were identified as CD68-positive macrophages surrounding the shadow cell nests. Immunohistochemistry of anti-human osteopontin antibodies revealed that the localization of osteopontin protein was consistent with that of calcium phosphate. The present results suggest that osteopontin produced by macrophages may play a significant role in the deposition of calcium phosphate in the shadow cell nests of pilomatricomas.

Amino Acid Sequence↗

PubMed1995

Efficient removal of albumin-bound furancarboxylic acid by protein-leaking hemodialysis.

Furancarboxylic acid (3-carboxy-4-methyl-5-propyl-2-furanpropionic acid, CMPF), an inhibitor of erythropoiesis, cannot be removed by conventional hemodialysis due to its strong albumin binding, resulting in its accumulation in uremic serum. We used protein-leaking hemodialysis with BK-F dialyzers in 8 uremic patients for 4 months to determine its effect on the serum levels of CMPF. Pre-hemodialysis serum levels of CMPF significantly decreased to about 50% after 4 months by protein-leaking hemodialysis, while those of BUN and serum creatinine did not change significantly. Pre-hemodialysis hematocrit and hemoglobin levels significantly increased by protein-leaking hemodialysis. These results indicate that protein-leaking hemodialysis reduces serum levels of albumin-bound CMPF and improves anemia.

Adult↗

PubMed1994

Cleavage at the N-terminal site of Alzheimer amyloid beta/A4 protein is essential for its secretion.

To characterize the secretory pathway of Alzheimer amyloid beta/A4 protein (beta/A4), mutated cDNAs of amyloid precursor protein (APP) were expressed transiently in COS cells. Although the expression of C100 (Met671-Asn770) resulted in the secretion of beta/A4-like peptide, the cells expressing the mutated APPs with the longer N-terminal domain beyond beta/A4 sequence secreted little beta/A4-like peptide. The C-terminal domain truncated APPs, with a stop codon at the end of beta/A4 sequence or the predicted membrane spanning domain produced little beta/A4-like peptide. When beta/A4 was expressed with direct addition of the signal sequence, beta/A4-like peptide was found in the cell lysate but little of it was secreted. Hence, the secretion of beta/A4 was started initially by cleavage at the N-terminal site of beta/A4, although cleavage at its C-terminal site was also necessary for its secretion.

Alzheimer Disease↗

PubMed1994

Heparin-binding epidermal growth factor-like growth factor is an autocrine growth factor for human keratinocytes.

Since heparin-binding epidermal growth factor (HB-EGF) is a member of the EGF family and binds to EGF receptor, we tested recombinant HB-EGF for its ability to stimulate human keratinocyte proliferation. The effect of HB-EGF on human keratinocytes was dependent on the cell density. HB-EGF optimally increased the cell number by 1.8-fold at 1.0 ng/ml for a 4-day incubation period under subconfluent culture. In contrast, under confluent culture, 10 ng/ml HB-EGF optimally increased the DNA synthesis 2.1-fold. To examine the production of HB-EGF by human keratinocytes, the analysis of human keratinocyte-conditioned medium was undertaken by a combination of heparin affinity column chromatography, EGF receptor-stimulating assay, immunoblotting, and neutralization. Heparin column chromatography fractionated three activities, peaks 1, 2, and 3, which contained immunoreactive 30- and 27-, 19-, and 14.5-kDa bands, respectively. The anti-HB-EGF-blocking antibody neutralized the activities of peaks 2 and 3 by 38 and 22%, respectively, but did not neutralize the activity of peak 1 at all. The antibody reduced the cell growth by 37% for a 4-day incubation period. Northern blot analysis detected a 2.5-kilobase transcript of HB-EGF. The addition of 1 ng/ml HB-EGF optimally increased the levels of HB-EGF mRNA 5.4-fold at 1 h and TGF-alpha mRNA 3.1-fold at 3 h. Interestingly, the addition of TGF-alpha at 1 ng/ml to keratinocyte cultures enhanced the level of HB-EGF mRNA 10.2-fold at 6 h. 1 ng/ml EGF also increased HB-EGF mRNA levels 10.9-fold at 1 h. These results suggest that HB-EGF is an autocrine growth factor for human keratinocytes, and HB-EGF and TGF-alpha act not only by an autoinductive mechanism but also by mutual amplification.

Cell Division↗

PubMed1994

Actin-binding protein, drebrin, accumulates in submembranous regions in parallel with neuronal differentiation.

Drebrins are developmentally regulated actin-binding proteins. In this study, we analyzed subcellular distribution of drebrin E in neuroblastoma cells (SH-SY5Y) in culture, especially in terms of its relationship to actin filaments. In undifferentiated cells, drebrin E was scattered as flocculus small dots along the stress fibers and also accumulated at adhesion plaques. In parallel with the neuronal differentiation following retinoic acid treatment, drebrin E was accumulated, accompanying filamentous (F) actin, in the submembranous cortical cytoplasm. Similar submembranous localization of drebrins was observed in primary cultured neurons. In the presence of drebrin E F-actin was more stable against cytochalasin D than F-actin lacking drebrin E. These results suggest that drebrin E plays a role in neuronal morphological differentiation by changing its subcellular localization with stabilized F-actin.

Actins↗

PubMed1994

Formation of thick, curving bundles of actin by drebrin A expressed in fibroblasts.

Drebrin A is a neuron-specific protein, the expression of which is regulated during development. Upon transfection of fibroblasts with drebrin A cDNA, the protein is expressed at high levels in fibroblasts and the outgrowth of highly branched, neurite-like cell processes is induced. In this report, we describe a biochemical examination of the binding of drebrin A to actin filaments. We also demonstrate by an immunocytochemical method that, when drebrin A is expressed in transfected cells, it binds to actin filaments and is concentrated in cell processes. Furthermore, we provide evidence that thick, curving bundles of actin together with drebrin are formed in some of the transfected cells. Our results suggest that the actin filaments that bind drebrin might be a novel class of actin filaments and might play a role in neuronal morphogenesis.

Actins↗

PubMed1994

Epstein-Barr virus-associated large granular lymphocyte leukemia with cutaneous infiltration.

A 36-year-old man had a high titer of antibody to Epstein-Barr virus (EBV) and recurrent necrotizing papules and nodules on his face and oral mucosa. The disease was diagnosed as CD3+4- 8+ large granular lymphocyte leukemia of T-cell origin. Southern blot analysis demonstrated that EBV DNA was present in CD8+ lymphocytes; EBV antigens were also observed in these lymphocytes. These findings demonstrated that EBV latently infected the leukemic cells and may have played a role in the pathogenesis of this disease. This is the first report of an association between EBV and large granular lymphocyte leukemia of T-cell origin.

Adult↗