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Biomedical subjects

M Nagata

Publications and source records attributed to M Nagata.

At least 217 records · Page 12Linked to original sources
PubMed1997

Synergistic activation of eosinophil superoxide anion generation by VCAM-1 and GM-CSF. Involvement of tyrosine kinase and protein kinase C.

During the development of allergic inflammation of asthma, eosinophils (EOS) are likely to interact with endothelial adhesion molecules, such as VCAM-1 and inflammatory cytokines, such as GM-CSF. To determine whether VCAM-1 and GM-CSF can interact to modify EOS superoxide anion (O2-) generation, peripheral blood EOS were incubated in either recombinant human (rh)-VCAM-1 or buffer (control)-coated 96-well plates in the presence or absence of 100 pM GM-CSF. VCAM-1 and GM-CSF acted synergistically to stimulate O2- generation which was significantly inhibited by either genistein, a tyrosine kinase inhibitor, or staurosporine, a protein kinase C inhibitor. These results indicate that interaction between VCAM-1 and GM-CSF can stimulate EOS function and its eventual contribution to the allergic inflammation process. Furthermore, our results demonstrate the involvement of tyrosine kinase and protein kinase C in this specific EOS activation.

Asthma↗
PubMed1997

Isolated maxillary bending in CL/FR strain mice: observation of craniofacial deformity and inheritance pattern.

OBJECTIVE: The CL/Fr mouse, known as a strain with spontaneous cleft lip and/or palate (CL/P), has been used as an animal model to investigate etiology in CL/P. METHOD: We examined a facial asymmetry mutant discovered in a CL/Fr mouse colony that was not associated with CL/P and was shown to be inheritable in subsequent generations. Facial asymmetry became apparent with postnatal growth, whereas it was not detectable at birth, and was termed "maxillary bending" (MB) based on the characteristic bending of the maxilla. RESULTS: As a result of selective breeding, an 'MB line', In which MB was observed in 21.68% (67/309) in addition to CL/P in 17.80% (55/309) of the offspring, was developed in the CL/Fr colony. In mating experiments between the MB line and C57BL/6J, all F1 progeny showed the normal phenotype. MB was observed in 0.72% (1/139) of the F2 generation, and the backcross generation showed segregation of MB in 6.25% (22/352) and CL/P in 1.42% (5/352). These instances suggested the occurrence of an additional mutation in the CL/Fr mouse genome controlled by an autosomal recessive gene with low penetrance. However, since the CL/Fr mouse primarily has a developmental deficiency in the maxilla, the possibility that CL/P and MB share common etiologic factors cannot be completely ruled out. CONCLUSION: The maxillary bending retains significance, as this mutant can serve as an animal model of abnormal facial growth. Elucidation of the etiologic relationship between MB and CL/P may provide clues to clarifying the deficiency in first branchial arch in the mouse.

Animals↗
PubMed1997

Anionic sites of charge barrier in the guinea pig crista ampullaris.

In present studies we obtained anionic sites in the epithelial and capillary basement membranes in the dark cell area of the crista ampullaris in the guinea pig. The immersion method with cationic tracer polyethyleneimine (PEI) was applied. Electronmicroscopically, the arrangement of PEI particles was observed as two strata along the basement membrane. The number of particles could be counted and compared in each portion. The control test with protamine sulfate showed that the number of PEI particles decreased in both the epithelium and capillaries of the dark cell area. In the experiment using furosemide, the stria vascularis and the dark cells had changed, with pathological findings of interstitial edema and PEI particles reduced in number. It is suggested that the PEI particles reflect different conditions of charge in the basement membrane, which influences the production or absorption of the inner ear fluid.

Absorption↗
PubMed1997

Effect of histamine on intracellular Ca2+ concentration in guinea pig isolated vestibular hair cells.

The present study examined the effects of histamine in the guinea pig isolated vestibular hair cells (VHCs) by measuring the dynamic changes of intracellular free calcium ion ([Ca2+]i) concentration using calcium sensitive dye Fura-2. The histamine-induced calcium response in VHCs was markedly increased at the concentration of 10 microM histamine in the presence of extracellular Ca2+, while in the absence of extracellular Ca2+, a slow increase of [Ca2+]i was evident. Receptor specificity of the response to histamine was examined: promethazine (H1 receptor antagonist), cimetidine (H2 receptor antagonist) and thioperamide (H3 receptor antagonist) completely blocked the histamine-induced calcium response at the concentrations of 2.5 microM, 1.0 microM and 1.0 nM, respectively. The responses were mediated by H1, H2 and H3 receptors and resulted in a rise of [Ca2+]i due to an influx of Ca2+ from the extracellular space and a release from intracellular stores. Our preliminary data suggest that under immuno-pathological conditions of the inner ear, histamine released from the mast cells distributed in the endolymphatic sac may act through receptors located on the vestibular hair cell membrane and may regulate the cell function and the signal transduction in the vestibular nerve-hair cell afferent system.

Afferent Pathways↗
PubMed1997

Trabeculotomy combined with phacoemulsification and implantation of an intraocular lens for the treatment of primary open-angle glaucoma and coexisting cataract.

BACKGROUND AND OBJECTIVE: The authors previously reported the usefulness of trabeculotomy ab externo for the treatment of primary open-angle glaucoma in adult patients. In an attempt to elucidate the long-term risk-to-benefit ratio of this surgical modality in combination with cataract surgery, the authors conducted a retrospective study of the surgical effects and complications of a triple procedure: phacoemulsification, implantation (of an intraocular lens), and trabeculotomy (PIT). PATIENTS AND METHODS: The authors conducted a retrospective study of patients treated with PIT at multiple hospitals. Intraocular pressure (IOP) and visual function data were obtained from patients after PIT as an initial surgical treatment in cases where antiglaucoma medications failed to resolve uncontrolled IOP (higher than 21 mm Hg). Included in this study were 96 eyes of 64 patients with primary open-angle glaucoma and coexisting cataract. The mean follow-up period was 22.6 +/- 14.7 months (range 3-56 months). RESULTS: In 94 (98%) of the 96 eyes, the IOP was well controlled, having achieved a level of 21 mm Hg or lower at the final examinations. The mean preoperative IOP of the 33 eyes that underwent the triple procedure using a single flap method (PIT-I) was 24.3 +/- 3.9 mm Hg, with an average of 2.1 +/- 1.1 medications. At the final examinations, the mean IOP had dropped to 16.0 +/- 1.2 mm Hg, with an average of 1.2 +/- 1.2 medications. The mean preoperative IOP of the 63 eyes that underwent the triple procedure using a double flap method (PIT-II) was 26.2 +/- 6.2 mm Hg, with an average of 1.9 +/- 1.2 medications. At the final examination, the mean IOP for this group was 15.6 +/- 2.9 mm Hg, with an average of 1.0 +/- 0.9 medications. CONCLUSION: The long-term results from this multicenter study showed that the triple procedure, PIT, can be useful and effective as an initial surgical treatment for open-angle glaucoma in glaucoma patients with coexisting cataract.

Adult↗
PubMed1997

Non-lethal junctional epidermolysis bullosa in a dog.

We report a 4-year-old female mongrel dog with a history since birth of erosions and atrophic skin, with pigmentation and alopecia on the face, trunk and extremities, together with dystrophic nails. Light microscopy revealed subepidermal blisters with minimal inflammation and electron microscopy confirmed that the ultrastructural site of separation site was at the lamina lucida. Indirect immunofluorescence of the dog's skin detected the positive expression of laminin 5, BPAG2, integrin-alpha 6 and type VII collagen. These clinical, ultrastructural and immunohistochemical features suggested that the dog had a non-lethal subtype of junctional epidermolysis bullosa (JEB). This is the first confirmed case of non-lethal JEB in a dog and presents a possible candidate for an animal model of gene therapy. Further study should provide important information of the phenotype, pathophysiology and prognosis of non-lethal JEB in humans.

Animals↗
PubMed1997

[The long-term cystic bleb appearance and safety after trabeculectomy with mitomycin C].

The clinical appearance of cystic blebs and the incidence of bleb infection were retrospectively evaluated in 215 trabeculectomies with mitomycin C. The incidence of cystic bleb formation in trabeculectomy was 79% (169/215). The cumulative incidence of the cystic bleb survival when using the Kaplan-Meier method was 73% in the 50th month after surgery. The incidence of large cystic bleb survival was better than that of small and localized cystic blebs. There was statistically significant difference. The incidence of cystic bleb survival without Seidel phenomenon and bleb infection was 96% in the first year after surgery and 91% in the third year. Bleb infections occurred in two of 169 eyes (1.2%). Bleb infection was successfully treated and there were no cases of endophthalmitis. The large cystic blebs had a higher incidence of bleb infection than the small ones. In one of 25 eyes treated with antibiotic eye drops after surgery, the Seidel test was positive and bleb infection occurred. The Seidel test was positive in 5 of 96 eyes in which antibiotic eye drops were not used and bleb infection occurred in one of these 5 eyes.

Female↗
PubMed1997

[A case of primary mediastinal choriocarcinoma].

A 27-year-old man with primary mediastinal choriocarcinoma was reported. He was admitted with complaint of right chest pain and dyspnea. Chest X-ray film and computed tomography of the chest revealed a bulky mass at anterior mediastinum and right pleural effusion. Physical examination revealed bilateral gynecomastia, and the serum beta-HCG level was cap at 500 ng/ml. The specimens obtained by percutaneous needle biopsy of the mediastinal mass showed cytotrophoblasts and syncytiotrophoblasts. He received 4 cycles of anti-cancer chemotherapy, and underwent resection for a residual mass, in which viable cancer cells remained in histological examination. In spite of additional chemotherapy, multiple lung metastasis developed rapidly. High dose chemotherapy, with carboplatine (200 mg/m2 x 4 days), etoposide (250 mg/m2 x 4 days) and cyclophosphamide (50 mg/kg x 2 days) was performed in combination with peripheral blood stem cell autotransplantation. However, brain metastasis set in and he died of respiratory failure 9 months after the onset of symptoms.

Adult↗
PubMed1997

Verruciform xanthoma in association with a vulval fibroepithelial polyp.

We report the clinical, light microscopic, immunohistochemical and ultrastructural features of a verruciform xanthoma that developed in association with a vulval fibroepithelial polyp. To our knowledge, this is the first time that this association has been reported. Immunohistochemical findings confirmed that the xanthoma cells were of a monocyte/macrophage lineage. In addition to typical histological characteristics, prominent vascular ectasias were detected in the deep dermis at the periphery of this lesion. The ectasias may play a part in pathogenesis.

Female↗
PubMed1996

Effect of isolation protocol on eosinophil function: Percoll gradients versus immunomagnetic beads.

Studies of in vitro eosinophil function are dependent on efficient and reliable methods of cell isolation. Protocols using Percoll or metrizamide density gradients have been of limited use in isolating peripheral blood eosinophils in sufficient numbers and purity from subjects with normal or only slightly elevated eosinophil counts, thereby restricting comparative studies to preparations from hypereosinophilic subjects. Recently, a method utilizing negative selection by anti-CD16 coated magnetic beads has greatly improved eosinophil isolation by dramatically increased yields and purity. However, little is known as to the differential effect of various isolation methods on the functional activity of eosinophils. In this study, eosinophils were isolated by either discontinuous multiple density Percoll gradients or anti-CD16-coated magnetic beads: several functional activities were then compared using cells obtained by the two methods of isolation. Compared with Percoll isolated eosinophils, anti-CD16 bead separated eosinophils had significantly increased baseline and stimulated LTC4 production, spontaneous O2- generation, and expression of specific cell surface markers. No significant difference was observed in the cells' in vitro survival and adhesion. Such differences may be due to the isolation of eosinophils of all densities by anti-CD16 beads, or the effect of neutrophils interacting with the beads to release eosinophil agonists or primers. Alternatively, the Percoll gradient method with the eosinophils' exposure to dextran and Ficoll-Hypaque may affect subsequent cell function. Therefore, comparison of eosinophil function between cells isolated by different protocols must be considered before concluding which is the true measure of in vivo cell function.

Adolescent↗
PubMed1996

Induction of tolerance in murine autoimmune diabetes by transient blockade of leukocyte function-associated antigen-1/intercellular adhesion molecule-1 pathway.

The present study demonstrated that a short-term administration of mAbs against leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) at critical periods resulted in complete protection of autoimmune diabetes in non-obese diabetic (NOD) mice. When these mAbs were administered for only 6 days at 2 wk of age, neither diabetes nor insulitis was observed at 30 wk of age. It appears that the tolerance against beta cell Ag(s) was induced by this transient blockade of the LFA-1/ICAM-1 pathway. Protective suppressor activity was not enough to prevent diabetes because co-transfer of splenocytes from female NOD mice, which had received these mAbs at 2 wk of age, resulted in only a short delay of the diabetic onset caused by adoptive transfer of splenocytes from acutely diabetic NOD mice. Transfer of these splenocytes to young NOD mice could not also abrogate the spontaneous diabetes and insulitis. Furthermore, cyclophosphamide treatment could not abrogate the protection. When splenocytes from the treated NOD mice were transferred to NOD-SCID mice, none of the recipient mice developed significant insulitis and subsequent overt diabetes, suggesting the absence or the inactivation of diabetogenic effector T cells. However, splenic T cells from the insulitis-free NOD mice that had received the mAb treatment preserved proliferative responses to both islet cells and 65-kDa glutamic acid decarboxylase (GAD65) in vitro. These results suggest that a unique peripheral tolerance was induced by the transient blockade of the LFA-1/ICAM-1 pathway in an early age of NOD mice.

Adoptive Transfer↗
PubMed1996

Human gene encoding prostacyclin synthase (PTGIS): genomic organization, chromosomal localization, and promoter activity.

The prostacyclin synthase gene isolated from human genomic libraries (PTGIS) consists of 10 exons spanning approximately 60 kb. All the splice donor and acceptor sites conform to the GT/AG rule. Genomic Southern blot and fluorescence in situ hybridization analyses revealed that the human prostacyclin synthase gene is present as a single copy per haploid genome and is localized on chromosome 20q13. 11-q13.13. The 1.5-kb sequence of the 5'-upstream of the translational initiation site contained both GC-rich and pyrimidine-rich regions and consensus sequences of the transcription factor recognition sites such as Sp1, AP-2, the interferon-gamma response element, GATA, NF-kappaB, the CACCC box, and the glucocorticoid response element. The core binding sequence (GAGACC) of the shear stress responsive element was also found in the 5'-flanking region of the gene. The major product of the primer extension analysis suggested that the transcription of the gene started from the positions around 49 bp upstream of the translational initiation codon. Transient transfection experiments using human aortic and bovine arterial endothelial cells demonstrated that the GC-rich region (positions -145 to -10) possessed a significant promoter activity. The 6-kb downstream sequence of the translational termination codon contained multiple polyadenylation signals, Alu repeat sequences, and the consensus sequence of the primate-repetitive DNA element, MER1. Two sizes of the prostacyclin synthase mRNAs (approximately 6 and 3.3 kb) were detected with the human aorta and lung. RNA blot hybridization analysis using the 3'-untranslated region as probe indicated that the sizes of the 3'-flanking regions were different in the major 6-kb and minor 3.3-kb mRNAs.

Animals↗
PubMed1996

Rat eosinophils: isolation and characterization of superoxide production.

Studies with isolated cells are important to the understanding of mechanisms by which eosinophils participate in allergic inflammation. Due to species variability, isolation techniques and cell biology need to be defined for each source. We developed methods to obtain rat eosinophils with purity and viability exceeding 90%, characterized the superoxide anion production of these cells in response to standard activators, and compared these results with those previously obtained in our laboratories with the use of human eosinophils. Rat eosinophils responded vigorously to phorbol myristate acetate and poorly to platelet-activating factor and to N-formyl-methionyl-leucyl-phenylalanine, parallel to the responses of human eosinophils. In contrast, rat eosinophils responded unlike human eosinophils to other activators, having a larger response to calcium ionophore A23187, a smaller response to serum-treated or serum-opsonized zymosan, and a negative rather than positive modulatory effect of cytochalasin B. We conclude that rat eosinophils can be obtained in high purity and with intact responsiveness to a number of different activators.

Animals↗
PubMed1996

Trabeculotomy ab externo, cataract extraction, and intraocular lens implantation: preliminary report.

PURPOSE: To compare the results of a triple procedure using either extracapsular cataract extraction (ECCE) or one of two phacoemulsification techniques combined with trabeculotomy ab externo and intraocular lens (IOL) implantation. SETTING: Kyoto University Hospital, Kyoto, Japan, and Nagata Eye Hospital, Nara, Japan. METHODS: In this comparative study, 25 eyes with primary open-angle glaucoma had ECCE combined with trabeculotomy ab externo and IOL implantation and 22 had the same procedure using phacoemulsification instead of ECCE. Of the eyes that had phacoemulsification, 10 had a single-flap and 12 had a double-flap procedure. RESULTS: All 22 eyes that had phacoemulsification had a postoperative IOP of 21 mm Hg or less, as did all ECCE eyes except 2. Although the self-sealing incision might have caused the higher incidence of IOP spikes in the immediate postoperative period, IOPs in the phacoemulsification groups were lower after 3 months. Results were similar in the single-flap and double-flap phacoemulsification groups. There were no significant complications. CONCLUSION: Cataract extraction by phacoemulsification or ECCE combined with IOL implantation and trabeculotomy ab externo is a safe, effective treatment for patients with coexisting glaucoma and cataract.

Aged↗
PubMed1996

An organic acid-induced sigmoidal release system for oral controlled-release preparations. 2. Permeability enhancement of Eudragit RS coating led by the physicochemical interactions with organic acid.

The drug release mechanism of the sigmoidal release system (SRS), which is a newly developed multiple-unit type time-controlled release system, was investigated. The drug release rate from the Eudragit RS-coated theophylline beads was considerably enhanced in succinic acid aqueous solution compared with the release rate in water. However, the drug release rate from the beads coated with Eudragit NE 30D, which has no quaternary ammonium groups in the polymer chain, was not affected by succinic acid, suggesting that the quaternary ammonium groups of Eudragit RS are essential to produce the unique drug release profile of the SRS. Ion-exchange experiments revealed that organic acids could interact with Eudragit RS by an ion exchanging mode to various extents depending on the acid species. To examine the individual effect of dissociated and undissociated forms of succinic acid on the drug release behavior of the Eudragit RS-coated theophylline beads, dissolution studies were performed in succinic acid or monosodium succinate aqueous solutions with various concentrations. The drug release rate was found to change depending on the concentration of either the dissociated or the undissociated form of succinic acid with different concentration dependency. From the glass transition temperature measurement using Eudragit RS cast film, it was assumed that the undissociated succinic acid was distributed to the hydrophobic segment of the polymer, resulting in the increase in mechanical flexibility of the film; whereas the dissociated succinic acid electrostatically interacted with the quaternary ammonium groups of the polymer to promote the distribution and to create new ionic circumstances: both effects of the organic acid can accelerate the hydration of Eudragit RS film. All these results suggest that the unique S-shaped drug release profile of SRS can be brought about by a drastic increase in the permeability through the hydration of Eudragit RS-based coating during the drug release process.

Acids↗