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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 307 records · Page 17Linked to original sources
PubMed1997

Short-term exposure to diesel exhaust induces nasal mucosal hyperresponsiveness to histamine in guinea pigs.

The increasing prevalence of allergic rhinitis in many countries is becoming a social problem. It is important to determine whether air pollutants are related to the increase in the prevalence rate of allergic rhinitis or not. In this respect, it is necessary to elucidate whether exposure to air pollutants affects the nasal mucosa and causes nasal mucosal hyperresponsiveness to chemical mediators released by antigen-antibody reactions. A previous study revealed that diesel exhaust particulates are potent in augmenting increases in nasal congestion and nasal secretion induced by histamine (T. Kobayashi and T. Ito, 1995, Fundam. Appl. Toxicol. 27, 195-202). In the present study, using a rhinitis model of guinea pigs, we investigated whether short-term (3-hr) exposure to diesel exhaust induces nasal mucosal hyperresponsiveness to histamine. Guinea pigs of each group were exposed to filtered air or to a low or high concentration of diesel exhaust (1 and 3.2 mg/m3 particulates in diluted diesel exhaust, respectively) for 3 hr. After diesel exhaust exposure, sneezing frequency, nasal secretion from the nostril, and intranasal airway resistance induced by histamine were measured as indices of sneezing response, rhinorrhea, and nasal congestion, respectively. Short-term exposure to a low or high concentration of diesel exhaust itself did not induce sneezing, nasal secretion, or nasal congestion. However, short-term exposure to a high concentration of diesel exhaust augmented sneezing and nasal secretion, but not nasal congestion, induced by histamine. In conclusion, short-term exposure to diesel exhaust potently induces nasal mucosal hyperresponsiveness.

Aerosols↗
PubMed1997

Intraorbital wooden and bamboo foreign bodies: CT.

We describe the CT findings of intraorbital wooden and bamboo foreign bodies in the acute, subacute, and chronic stages. We examined four patients using CT a total of seven times. The CT findings were reviewed. There were three dry wooden foreign bodies. CT within a day of the accident demonstrated wooden foreign bodies as low density relative to surrounding orbital fat, while CT 8-29 days after the accident showed them as denser than the extraocular muscles. In the acute stage, dry wooden foreign bodies mimic air bubbles. Wooden foreign bodies in the subacute and chronic stages should be included in the differential diagnosis of intraorbital lesions of soft tissue density or above on CT of traumatised orbits. There was one dry bamboo foreign body. Within a day of the accident it was recognised as linear lesion isodense with fat. Therefore, such foreign bodies may be missed on CT when located in the orbital fat.

Adipose Tissue↗
PubMed1997

CT and MRI of sellar spine with upward extension of the pituitary gland: case report.

This is a report of CT and MRI findings in a patient with a sellar spine which caused deformity of the pituitary gland. The sellar spine is an infrequent anatomical variant characterized by an osseous spine which arises in the midline from the anterior aspect of the dorsum sellae and extends into the pituitary fossa. The CT and MRI findings of sellar spine have been described in previous reports; however, only one investigator reported deformity of the pituitary gland as revealed by CT. This is the first report of the MRI finding of the sellar spine associated with a deformity and superior extension of the pituitary gland, mimicking pituitary hypertrophy.

Adolescent↗
PubMed1997

Spinal cord herniation: report of two cases and review of the literature.

Idiopathic herniation of the spinal cord is an extremely rare disorder which may cause progressive myelopathy. Two cases of this entity reported herein were both examined using MRI and CT myelography. The typical appearance of this disease with or without a dorsal intradural arachnoid cyst is focal ventral displacement of the mid-thoracic spinal cord, mimicking an isolated intradural spinal arachnoid cyst on MRI. CT myelography using thin slice sections is useful in the diagnosis of this disease.

Aged↗
PubMed1997

Lack of evidence for the transmission of JC polyomavirus between human populations.

Human polyomavirus JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy, is ubiquitous in humans, infecting children asymptomatically then persisting in renal tissue. Since JCV DNA can readily be detected from urine, it should be a useful tool with which to study the mode of virus transmission in humans. Based on this notion, we examined the extent to which JCV was transmitted from the American to Japanese populations in Okinawa Island, Japan. (A population of about 50 000 American soldiers and families have been stationed in Okinawa since 1945.) Four JCV types (A to D) were identified in American populations in U.S.A., whereas only type B was prevalent in elder Japanese in Okinawa who had reached adulthood by 1945. Thus, types A, C, and D served as indicators of the transmission of JCV from American to Japanese populations. We then examined whether types A, C, and D were detectable in Japanese in Okinawa aged 30-50 years who may have been in contact with Americans during childhood. However, all the 125 isolates from the younger Japanese population were type B without exception. From this finding, we concluded that JCV is rarely transmitted between human populations.

Adult↗
PubMed1997

Varietal differences in protein phosphorylation during cold treatment of rice leaves.

The effects of cold stress on protein phosphorylation in leaves of rice (Oryza sativa) seedlings were investigated. Two-week-old rice seedlings were exposed to low temperature (5 degrees) for 6 hr at a relative humidity of 100%. The leaf protein extracts were phosphorylated in vitro. Cold stress stimulated the phosphorylation of a 60 kDa protein in the cold-sensitive rice variety, IR36. In the cold-tolerant rice variety, Kitaibuki, this protein had already been phosphorylated. For greater clarificating of these changes, the effects of cold on rice varieties differing in cold susceptibility were examined. Cold-sensitive rice varieties showed similar the protein phosphorylation in contrast to the cold-tolerant rice varieties.

Cold Temperature↗
PubMed1997

Platelet activating factor compromises airway epithelial defense functions.

BACKGROUND: The mechanism of disruption of the epithelial defense function observed in asthmatic airways is considered to be largely the result of mediators involved in allergic responses. Platelet activating factor (PAF) might be a key mediator involved in this mechanism. OBJECTIVE: This study was designed to determine whether PAF is capable of compromising the epithelial defense functions, such as tight junctional barriers and the mucociliary system. METHODS: A total of 120 healthy rabbits were used. Twenty of them were used as normal controls. Eighty rabbits were treated with inhalation of 10 ml of PAF (200 microg/ml), and 20 animals were used for the examination of epithelial defense functions of the trachea at 1, 10, 20, and 30 days after inhalation of PAF. Epithelial defense functions of the trachea were evaluated by ciliary activity, mucociliary transport velocity, epithelial permeability to fluorescein isothiocyanate dextrans (70,000 d), and electron microscopy of the epithelial structure. RESULTS: PAF inhalation induced a significant decrease in ciliary activity and mucociliary transport velocity, which persisted for up to 20 days. PAF inhalation also caused a significant 7.4-fold increase in epithelial permeability to fluorescein isothiocyanate dextrans at I and 10 days. This increased epithelial permeability returned to the normal level 20 days after PAF inhalation. However, electron microscopy demonstrated no apparent evidence of epithelial shedding. CONCLUSIONS: PAF-induced prolonged dysfunction of both the epithelial junctional barrier and the mucociliary system may allow enhanced entry of allergen molecules, as well as bronchoactive agonists to the airway parenchyma and may also significantly contribute to an increased airway responsiveness.

Administration, Inhalation↗
PubMed1997

Serum levels of specific IgE, soluble interleukin-2 receptor, and soluble intercellular adhesion molecule-1 in seasonal allergic rhinitis.

BACKGROUND: There is increasing evidence that soluble interleukin-2 receptor (sIL-2R) might reflect T cell activation in vivo and soluble intercellular adhesion molecule-1 (sICAM-1) might reflect the ongoing inflammatory response in the inflamed site. OBJECTIVE: The aim of this study was to determine the effect of antihistamine tablets and allergen-specific immunotherapy on the seasonal changes in specific IgE, sIL-2R, and sICAM-1 in the serum of patients with seasonal allergic rhinitis. METHODS: This prospective study included 99 patients with seasonal allergic rhinitis due to Japanese cedar pollens and 27 nonatopic healthy volunteers. The patients were divided into an antihistamine-treated group and an immunotherapy group. Serum samples were collected before and during the pollen season from each patient to determine specific IgE, sIL-2R, and sICAM-1. RESULTS: Levels of sIL-2R before the pollen season did not differ significantly among the nonatopic group, the antihistamine-treated group, and the immunotherapy group. The levels of sICAM-1 before the pollen season were significantly higher in the antihistamine-treated group and in the immunotherapy group than in the nonatopic group. Seasonal increase in specific IgE was significant in the antihistamine-treated group regardless of their clinical outcomes. In contrast, significant increase in specific IgE was observed during the pollen season in poor responders but not in good responders to immunotherapy. Serum levels of sIL-2R and sICAM-1 were significantly increased during the pollen season in poor responders of the antihistamine-treated group and the immunotherapy group. On the other hand, neither seasonal increase in sIL-2R nor sICAM-1 was significant in good responders of the antihistamine-treated group and the immunotherapy group. CONCLUSIONS: Serum levels of sICAM-1 are higher in patients with seasonal allergic rhinitis, even outside of the pollen season when the allergen does not naturally exist. Seasonal changes in serum sICAM-1 as well as sIL-2R and specific IgE are probably objective markers to indicate the clinical efficacy of antihistamines and immunotherapy on seasonal allergic rhinitis.

Adult↗
PubMed1997

Hypoglycemic activity of some triterpenoid glycosides.

Four triterpenoid glycosides isolated from the rhizomes of Polygala senega var. latifolia, senegins II-IV (1-3) and desmethoxysenegin II (4), were tested for hypoglycemic activity in normal and KK-Ay mice. Compounds 1 and 2 reduced the blood glucose of normal mice 4 h after intraperitoneal administration and also significantly lowered the glucose level of KK-Ay mice under similar conditions. Compounds 3 and 4, as well as senegose A (5), an oligosaccharide ester, were inactive when tested against normal mice.

Animals↗
PubMed1997

Fagomine isomers and glycosides from Xanthocercis zambesiaca.

50% aqueous MeOH extracts from the leaves and roots of Xanthocercis zambesiaca (Leguminosae) were subjected to various ion-exchange column chromatographic steps to give fagomine (1), 3-epi-fagomine (2), 3,4-di-epi-fagomine (3), 3-O-beta-D-glucopyranosylfagomine (4), and 4-O-beta-D-glucopyranosylfagomine (5). Their structures were determined by spectroscopic analyses, particularly by extensive 1D and 2D NMR studies. Compounds 3 and 4 are new natural products. Compound 1 is a good inhibitor of isomaltase and certain alpha- and beta-galactosidases. Whereas 2 is a more potent inhibitor of isomaltase and beta-galactosidases than 1, it does not inhibit alpha-galactosidase. Compounds 3-5 exhibited no significant inhibition against the glycosidases used.

Animals↗
PubMed1997

The effect of immunotherapy on the serum levels of eosinophil cationic protein in seasonal allergic rhinitis.

The role of serum eosinophil cationic protein levels in allergic rhinitis is controversial. It is also unclear whether with immunotherapy it is possible to reduce these serum levels in allergic diseases. We studied serum eosinophil cationic protein levels in patients with cedar-induced allergic rhinitis and compared them with non-atopic controls. The second aim of this study was to elucidate whether immunotherapy is capable of decreasing the seasonal elevation in serum eosinophil cationic protein levels in seasonal allergic rhinitis. The serum eosinophil cationic protein levels of the untreated patient group were significantly higher than those of the non-atopic controls. The levels in patients who received immunotherapy for 2 yr were also significantly higher than those of the non-atopic controls. However, the levels were not different between the patients undergoing immunotherapy for over 3 yr and the non-atopic controls. The serum levels of the 31 patients treated with immunotherapy correlated with the duration of immunotherapy. In conclusion, the serum eosinophil cationic protein levels are higher in untreated patients with seasonal allergic rhinitis and this seasonal activation in circulating eosiohophils decreases gradually during immunotherapy, but this inhibitory effect becomes apparent only after a number of years of immunotherapy. This prevention of seasonal eosinophil activation is one of the mechanisms responsible for the clinical effect of immunotherapy.

Adolescent↗
PubMed1997

Sendai virus-based expression of HIV-1 gp120: reinforcement by the V(-) version.

BACKGROUND: We have established a system for recovering Sendai virus (SeV), a nonsegmented negative strand RNA virus, entirely from cDNA at an extremely high rate, and have succeeded in creating a V(-) SeV whose gene expression was greatly enhanced by the deletion of the nonessential V gene. Because of its extreme medical importance, there has been a strong need for the establishment of a better system to express the gp120 envelope glycoprotein of the human immunodeficiency virus type 1 (HIV-1) in sufficient quantity and purity. It also remains to be established to produce gp120 in in vitro natural host cells for HIV-1 such as human primary blood mononuclear cells, macrophages or established T cell lines. RESULTS: Using the above system, we created recombinant Sendai viruses expressing the gp120 in CV1 cells, a monkey kidney line. The expression level from the standard V(+) version has already reached 2.2/microg per 10(6) infected cells, which was readily purified from the culture fluid with a recovery rate of about 60%, and has so far appeared to be functionally and serologically authentic. The inserted gp120 gene was stably maintained during numerous passages of the recombinant virus. The V(-) version-based expression was even more robust, consistently reaching over 6.0 microg per 10(6) cells, a level that is one of the highest currently attainable for gp120 production in mammalian cells. Furthermore, a broad host range of SeV allowed gp120 production in all the three natural host cells for HIV-1 described above. CONCLUSIONS: SeV-based expression serves as a novel choice for producing large quantities of HIV-1 gp120 and will greatly facilitate biochemical, biological and immunological studies of this important glycoprotein.

DNA, Recombinant↗
PubMed1997

Nasal T/NK cell lymphomas commonly express perforin and Fas ligand: important mediators of tissue damage.

AIMS: Two molecular mechanisms of T/natural killer (NK) cell-mediated cytotoxicity, one perforin based and the other Fas based, have been demonstrated, and both systems induce cytotoxicity in the target cells. The Fas-based mechanism involves the transducing molecule Fas and its ligand (FasL). In addition, perforin and/or FasL are also expressed in the cytotoxic T/NK cells. This study was thus designed to investigate the Fas and perforin pathways of the cytotoxic T/NK lymphoma cells in the nasal cavity. METHODS AND RESULTS: Eight patients with nasal lymphoma were analysed using immunohistochemical staining methods. Two cases were CD3+ CD56+ (T/NK cell) type, and six were CD3- CD56+ (NK cell) type. All cases showed Epstein-Barr virus genomes by in-situ hybridization. In addition, all cases showed the expression of TIA-1 (GMP-17), which is a marker of cytotoxic T and NK cells. FasL was expressed in the majority of the lymphoma cells and some histiocytes, while Fas was found in lymphoma cells and many non-neoplastic cells. In addition, the expression of perforin was detected in almost all lymphoma cells. In the double stainings, lymphoma cells expressed both FasL and perforin. Based on these findings, both the perforin- and Fas-based pathway of the cytotoxic T/NK lymphoma cells are thus considered to play an important role in the clinical features. CONCLUSIONS: Tissue damage is a common morphological feature in nasal T/NK cell lymphoma. The above findings therefore support the theory that tissue damage is due to both the cytotoxicity of T/NK lymphoma cells as well as to angiocentricity.

Adult↗
PubMed1997

Serum level of soluble interleukin-2 receptor in patients with seasonal allergic rhinitis.

The rate of release of the soluble form of interleukin-2 receptor (soluble IL-2R) reflects T cell activation in vivo. Since T lymphocytes play a central role in respiratory allergic disorders, the measurement of serum levels of soluble IL-2R may be useful in analysing the disease state of allergic disorders. The study has aimed at investigating the seasonal changes in serum soluble IL-2R in 81 patients with seasonal allergic rhinitis due to Japanese cedar pollens, with special reference to the effect of anti-allergic pharmacotherapy and immunotherapy. Serum samples were obtained twice from each patient, before and during the pollen season, and all the serum samples were simultaneously used for determination of soluble IL-2R and cedar pollen-specific immunoglobin E (IgE). Seasonal elevation in soluble IL-2R was not associated with the good clinical outcome but was associated with the poor clinical outcome, irrespective of pharmacotherapy or immunotherapy. Additionally, successful immunotherapy suppressed seasonal elevation of serum soluble IL-2R more strongly than successful pharmacotherapy, and seasonal increase rates in soluble IL-2R were inversely correlated with the duration of immunotherapy. Seasonal increase rates in soluble IL-2R were significantly correlated with seasonal increase rates in specific IgE in both the medication group and the immunotherapy patients. These results may suggest that seasonal changes in serum soluble IL-2R may serve as an indicator for clinical outcome of seasonal allergic rhinitis, that the magnitude of T cell activation could affect specific IgE production, and that T cell activation could be gradually modulated as immunotherapy proceeds. In conclusion, seasonal changes in serum soluble IL-2R may serve as an objective indicator for clinical outcome of seasonal allergic rhinitis.

Adolescent↗
PubMed1997

Immunotherapy affects the seasonal increase in specific IgE and interleukin-4 in serum of patients with seasonal allergic rhinitis.

This study was designed to determine seasonal changes in cytokines, soluble CD23 and specific IgE in the serum of patients with seasonal allergic rhinitis, and the effect of immunotherapy on these seasonal changes. Fifty-four patients with seasonal allergic rhinitis caused by Japanese ceder pollens were divided into a medication group and an immunotherapy group. The patients of the medication group were treated with non-sedating antihistamines alone during the pollen season. The patients of the immunotherapy group had been treated for variable periods (mean, 5.0 +/- 3.2 years) with immunotherapy using japanese cedar pollen antigens. Serum samples were collected before and during the pollen season from each patient, to determine specific IgE, interleukin-4 (IL-4), interferon-gamma (IFN-gamma) and soluble CD23 levels in serum. A significant increase in specific IgE and IL-4 and a significant decrease in IFN-gamma were observed during the pollen season in the medication group. In contrast, in the immunotherapy group, none of specific IgE, IL-4 and IFN-gamma was significantly changed following natural exposure to pollens. However, these effects were not significant in patients undergoing immunotherapy for 3 or fewer years. Seasonal rates of increase in specific IgE and IL-4 differed significantly between good responders and poor responders to immunotherapy, but seasonal rates of decrease in IFN-gamma did not. A seasonal rate of increase in soluble CD23 was significantly correlated with a seasonal rate of increase in specific IgE, in both the medication and the immunotherapy groups. The seasonal rate of increase in soluble CD23 was significantly smaller in the good responders than in the poor responders to immunotherapy. In conclusion, pollen immunotherapy reduces the seasonal increase in specific IgE, IL-4 and soluble CD23 in serum, and in addition switches the seasonal preferential activation of Th-2 cells to reciprocal activation of Th-1 cells with treatment over several years. It is likely that the mechanisms responsible for the clinically beneficial effects of immunotherapy principally involve the modulation of Th-2 rather than Th-1 cytokines.

Adult↗
PubMed1997

Light-responsive elements of the tobacco PSI-D gene are located both upstream and within the transcribed region.

psaDb is a nuclear gene encoding the ferredoxin-binding subunit of photosystem I in Nicotiana sylvestris. The organization of the light-responsive cis-elements of psaDb was studied using transgenic tobacco plants. Three types of psaDb chimeric constructs were created: (1) a 5' upstream fragment of psaDb transcriptionally fused with the beta-glucuronidase (GUS) gene, and a series of its 5' deletion derivatives, (2) the transcribed region of psaDb driven by the cauliflower mosaic virus (CaMV) 35S promoter, and (3) the 5' terminal 35 bases (the entire leader, +1 to +23, and the initiation codon context, +24 to +35) of the psaDb mRNA translationally fused with a GUS reporter gene under the operation of the CaMV 35S promoter. Light-responsiveness of these fusions in transgenic plants was examined by GUS assay and primer extension analysis. The results indicate that the light-responsive elements (LRE) of psaDb are located both upstream (-170 to +24) and within (+1 to +861) the transcribed region. The internal LRE is utilized in etiolated seedings but not in green leaves. The leader and initiation codon context construct (+1 to +35) did not show any light-response under the conditions tested. Therefore, it is likely that a combination of the upstream and internal LREs generates the complex light-responsive and tissue-specific regulation of this gene. This study also revealed that psaDb has adjacent activator (-267 to -254) and repressor (-253 to -234) regions for basal transcriptional activity; the former contains the ACGT binding motif recognized by many plant bZIP proteins, and the latter has the R3 decamer motif found in several photosystem I-related genes.

Base Sequence↗