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Biomedical subjects

K Uehara

Publications and source records attributed to K Uehara.

At least 73 records · Page 4Linked to original sources
PubMed1997

Molecular cloning and characterization of beta-1,4-galactosyltransferase expressed in mouse testis.

Using an affinity-purified antibody against beta-1,4-galactosyltransferase purified from F9 embryonal carcinoma cells, we screened a lambda gt11 expression library constructed from the same cell line. The cDNA clone obtained encoded a 46-kDa protein. Among adult mouse organs, the testis was found to express large amounts of the corresponding mRNA. An antibody against the 46-kDa protein was raised in a rabbit by immunization with a maltose-binding-protein fusion protein produced in Escherichia coli. The affinity-purified antibody against the cloned 46-kDa protein reacted with a 59-kDa protein in sperm extract on western blotting. Among the proteins in the F9 beta-1,4-galactosyltransferase preparation, which were mostly 68-kDa and 59-kDa species, 59-kDa and 50-kDa bands reacted with the antibody against the cloned 46-kDa protein. The cloned 46-kDa protein had type-II transmembrane topology and some blocks of sequence similarity with the known beta-1,4-galactosyltransferase. Furthermore, predicted secondary structures were similar over large portions of the two proteins. The histidine-tagged 46-kDa protein produced in E. coli was partially adsorbed onto a N-acetylglucosamine-Affi-Gel column and eluted by 20 mM N-acetylglucosamine. The histidine-tagged 46-kDa protein, which was purified to homogeneity, had a small, but significant amount of beta-1,4-galactosyltransferase activity. These results strongly suggest that the 46-kDa protein is a beta-1,4-galactosyltransferase.

Amino Acid Sequence↗
PubMed1997

Adenovirus-mediated gene transfer and expression of human beta-glucuronidase gene in the liver, spleen, and central nervous system in mucopolysaccharidosis type VII mice.

Mucopolysaccharidosis type VII (Sly syndrome) is a lysosomal storage disease caused by inherited deficiency of the lysosomal enzyme beta-glucuronidase. A murine model of this disorder has been well characterized and used to study a number of forms of experimental therapies, including gene therapy. We produced recombinant adenovirus that expresses human beta-glucuronidase and administered this recombinant adenovirus to beta-glucuronidase-deficient mice intravenously. The beta-glucuronidase activities in liver and spleen were elevated to 40% and 20%, respectively, of the heterozygote enzymatic level at day 16. Expression persisted for at least 35 days. Pathological abnormalities of these tissues were also improved, and the elevated levels of urinary glycosaminoglycans were reduced in treated mice. However, the beta-glucuronidase activity in kidney and brain was not significantly increased. After administration of the recombinant adenovirus directly into the lateral ventricles of mutant mice, the beta-glucuronidase activity in crude brain homogenates increased to 30% of heterozygote activity. Histochemical demonstration of beta-glucuronidase activity in brain revealed that the enzymatic activity was mainly in ependymal cells and choroid. However, in some regions, the adenovirus-mediated gene expression was also evident in brain parenchyma associated with vessels and in the meninges. These results suggest that adenovirus-mediated gene delivery might improve the central nervous system pathology of mucopolysaccharidosis in addition to correcting visceral pathology.

Adenoviridae↗
PubMed1997

Junctions between the sinus endothelial cells of rat spleen.

Junctions between the sinus endothelial cells of rat spleen were examined by electron microscopy, using both freeze-fracture and detergent-extraction techniques. Adherens and tight junctions were observed. Adherens junctions were the predominant junctional structures between endothelial cells and were located on basolateral and lateral surfaces. At the basolateral adherens junctions, actin filaments were associated with the junctional membranes and were continuous with the actin filaments in stress fibers. Cross-bridges were present in the interspaces of the adherens junctions and spacing of the bridges was fairly regular. A form of tight junction, the macula occludens, was also observed between the endothelial cells, but it was not observed at every cellular apposition. Electron-dense material, adjoining the cytoplasmic surfaces of membranes in the tight junctions, separated the junctional membranes from masses of thin filaments. At basolateral tight junctions, the actin filaments were continuous with those in the stress fibers. Based on these observations, the two intercellular junctions were considered to play important roles in sinus functions.

Animals↗
PubMed1997

Morphological changes and hypomethylation of DNA in transgenic tobacco expressing antisense RNA of the S-adenosyl-L-homocysteine hydrolase gene.

S-adenosyl-L-homocysteine hydrolase (SAHH) is a key enzyme in the regulation of intracellular methylation reactions. To investigate the role of SAHH in methylation reactions and morphogenesis in planta, we have made transgenic plants expressing antisense RNA of tobacco SAHH. The transgenic plants displayed distinct morphological changes including a floral homeotic change. We hypothesized that the changes were caused by increased levels of cytokinin. In those transgenic plants, we observed that a repetitive DNA sequence appeared less methylated than controls. We speculated that altered gene expressions by the hypomethylation of DNA might be involved in the changes.

Adenosylhomocysteinase↗
PubMed1997

Active inhibitory effect of nafamostat mesylate against the elevation of plasma myeloperoxidase during hemodialysis.

Plasma levels of myeloperoxidase (MPO) were compared between hemodialysis (HD) sessions using heparin and those using nafamostat mesylate (NM) as an anticoagulant by an enzyme immunoassay established in our laboratory. MPO levels were markedly elevated during the entire HD procedure with heparin. In contrast, MPO levels were scarcely elevated during the HD with NM. On the other hand, polymorphonuclear leukocyte-elastase was markedly elevated during both of these HD procedures. These observations indicated that NM selectively attenuated MPO elevation in vivo during HD. This inhibitory effect of NM was further investigated ex vivo. Blood samples from a normal subject were collected with heparin alone, NM alone and a mixture of heparin and NM. Each sample was then circulated in a closed circuit composed of a dialyzer with a cuprophane membrane. MPO levels with heparin alone were shown to markedly rise in the closed system. In contrast, levels of MPO in the blood samples mixed with NM were not elevated even in the presence of heparin. These ex vivo results indicate that NM has an active inhibitory effect on the elevation of plasma MPO induced by granulocyte activation through a dialysis membrane. Our results demonstrate that clinical use of NM as an anticoagulant serves to selectively suppress MPO elevation considered as a consequence of granulocyte activation during HD.

Adult↗
PubMed1997

Resistance to UV-irradiation of DNA synthesis in fibroblast cell lines derived from LEC strain rats.

After UV-irradiation, no difference in the survival curves was observed among cell lines derived from LEC strain (LEC) rats and WKAH strain (WKAH) rats. The dose-response curves for inhibition of DNA synthesis in WKAH-derived cells showed a sharp decline at lower doses and a mild decline at higher doses of UV-rays. In contrast, the dose-response curves in LEC-derived cell lines had no sharp component, and were almost identical to the mild component of the curves in WKAH-derived cells. These results show that DNA synthesis in the cell lines of LEC rats was more resistant to UV-irradiation than that of WKAH rats.

Animals↗
PubMed1997

Abnormal G1 arrest in the cell lines from LEC strain rats after X-irradiation.

The effect of X-irradiation of cell lines from LEC and WKAH strain rats on a progression of cell cycle was investigated. When WKAH rat cells were exposed to 5 Gy of X-rays and their cell cycle distribution was determined by a flow cytometer, the proportion of S-phase cells decreased and that of G2/M-phase cells increased at 8 hr post-irradiation. At 18 and 24 hr post-irradiation, approximately 80% of the cells appeared in the G1 phase. On the contrary, the proportion of S-phase cells increased and that G1-phase cells decreased in LEC rats during 8-24 hr post-irradiation, compared with that at 0 hr post-irradiation. Thus, radiation-induced delay in the progression from the G1 phase to S phase (G1 arrest) was observed in WKAH rat cells but not in LEC rat cells. In the case of WKAH rat cells, the intensities of the bands of p53 protein increased at 1 and 2 hr after X-irradiation at 5 Gy, compared with those of unirradiated cells and at 0 hr post-irradiation. In contrast, the intensities of the bands were faint and did not significantly increase in LEC rat cells during 0-6 hr incubation after X-irradiation. Present results suggested that the radioresistant DNA synthesis in LEC rat cells is thought to be due to the abnormal G1 arrest following X-irradiation.

Animals↗
PubMed1996

Efficient production of Thermus protease aqualysin I in Escherichia coli: effects of cloned gene structure and two-stage culture.

The DNA sequence encoding Thermus protease aqualysin I was inserted downstream from a bacteriophage T7 promoter in an expression vector. In the T7 expression system, using a strain lacking an F' episome, aqualysin I was produced in soluble form without chemical induction. The deletions of part (30 amino acid residues) or all (105 residues) of the C-terminal pro-sequence from the C terminus significantly affected both cellular growth and the production of the enzyme. Complete deletion adversely affected both. In contrast, the 30-residue deletion markedly improved productivity by approximately four times compared to non-deletion, and shortened the time needed for the activation of a precursor to active enzyme. The concentration of inducer isopropyl beta-D-thiogalactopyrano-side (IPTG) was varied to examine its effects, and it was found that a low concentration of IPTG improved aqualysin I production. To avoid the inhibitory effects of acetic acid accumulation in the culture medium, the use of other carbon sources besides glucose was examined. When cells were cultivated with glycerol, the acetic acid level remained relatively low, and both good cellular growth and a high level of production were attained. The aqualysin I productivity for a fed-batch culture using two carbon sources, glucose and glycerol, reached more than 150 kU/ml enzymatically active aqualysin I.

Bacteriophage T7↗
PubMed1996

Massive endobronchial hemorrhage after pulmonary embolectomy.

Massive endobronchial hemorrhage is a lethal complication in pulmonary embolectomy. We report a case of massive endobronchial hemorrhage occurring after successful restoration of pulmonary blood flow using cardiopulmonary bypass in a patient with pulmonary embolism. Two possible causative factors of this complication are described.

Adult↗
PubMed1995

FT-IR and near-infrared FT-Raman study of aggregation of bacteriochlorophyll c in solutions: evidence for involvement of the ester group in the aggregation.

Ultraviolet-visible (UV-Vis) absorption, Fourier-transform infrared (FT-IR), and near-infrared (NIR)-excited FT-Raman spectra have been measured for bacteriochlorophyll c (BChl-c) in acetone, tetrahydrofuran (THF), pyridine-d5, carbon disulfide (CS2), and water-saturated carbon tetrachloride (CCl4) to investigate its aggregation in vitro. The UV-Vis absorption spectra can be classified into two groups. Group I (acetone, THF, and pyridine-d5 solutions) gives a spectrum with a Qy band around 665 nm while group II (CS2 and water-saturated CCl4 solutions) shows a spectrum typical of BChl-c aggregates with a broader red-shifted Qy band. All the NIR-FT-Raman spectra, which are preresonant with the Qy band, are very close to those of chlorophyll a (Chl-a) measured in the corresponding solutions. Bands due to a C = O stretching mode of free and strongly hydrogen-bonded 13(1)-keto carbonyl groups appear near 1685 and 1645 cm-1, respectively. In contrast to the FT-Raman spectra, FT-IR spectra of the pyridine-d5 solution and group II are largely different from those of Chl-a in the corresponding solutions, suggesting that BChl-c forms quite different types of aggregates. It is clear from the IR spectra that the ester carbonyl group plays an important role in the aggregation for the pyridine-d5 and group II solutions. Of particular note is that bands due to C = O stretching modes of the ester group are observed at 1733, 1719, and 1705 cm-1 in the spectrum of BChl-c in water-saturated CCl4.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1995

Broad resistance to plant viruses in transgenic plants conferred by antisense inhibition of a host gene essential in S-adenosylmethionine-dependent transmethylation reactions.

S-Adenosylhomocysteine hydrolase (SAHH) is a key enzyme in transmethylation reactions that use S-adenosylmethionine as the methyl donor. Because of the importance of SAHH in a number of S-adenosylmethionine-dependent transmethylation reactions, particularly the 5' capping of mRNA during viral replication, SAHH has been considered as a target of potential antiviral agents against animal viruses. To test the possibility of engineering a broad type of resistance to plant viruses, we expressed the antisense RNA for tobacco SAHH in transgenic tobacco plants. As expected, transgenic plants constitutively expressing an anti-sense SAHH gene showed resistance to infection by various plant viruses. Among those plants, about half exhibited some level of morphological change (typically stunting). Analysis of the physiological change in those plants showed that they contained excess levels of cytokinin. Because cytokinin has been found to induce acquired resistance, there is also a strong possibility that the observed resistance was induced by cytokinin.

Journal Article↗
PubMed1995

Distribution of Dermatophagoides mite (Acari: Pyroglyphidae) antigens in homes of allergic patients in Japan.

Dust samples collected in 61 homes of patients with mite allergies and 11 homes of non-allergic people as controls were examined for antigen levels of Dermatophagoides farinae Hughes and Dermatophagoides pteronyssinus (Trouessart) to reveal the current distribution of allergenic mites in homes in Japan. Patient homes had higher antigen levels than control homes in comforters and pillows but not in futons, carpets, tatamis and wooden floors. Samples with antigen levels of > or = 10 micrograms m-2 were more frequent in and around summer (approximately April-October) than other seasons of the year in most materials and the differences between patient and control homes in comforters and pillows observed in yearly totals was also observed during this period. Wooden structures showed higher antigen levels than concrete structures in comforters, futons, pillows, carpets and tatamis in patient homes. Mite contamination in patient homes in relation to environmental factors was discussed.

Adult↗
PubMed1995

Cutaneous malignant hemangioendothelioma: clinical and histopathological observations of nine patients and a review of the literature.

Nine patients with cutaneous malignant hemangioendothelioma (CMHE) were reported in Okinawa. All the patients were elderly, between 75 and 93 years of age. Four patients were males and five were female. The onset of the disease ranged from 1 to 9 months before the first visit. Eight patients had lesions on the scalp, and one, on the face and cheek. The lesions were in the form of exudative erythematous purpura, erythematous purpuric ulcers, and tumors. One patient developed a systematic metastasis involving the lungs, heart and intestine, and two patients had local metastasis to the cervical lymph nodes. Histopathologically, the tumor vessels were proliferated irregularly and showed anastomosis. The lumens were lined by large and atypical endothelial cells. Most of the specimens were infiltrated with large numbers of red blood cells. By electron microscope, Weibel-palade bodies were found inside the tumor cells located at the peripheral part of the lesion. The patients were treated by irradiation, IL-2 injection, and/or surgery. They were treated for 3 months to 2 years. Eight patients died between 4 to 24 months after the onset of disease and one has survived. The prognosis was poor.

Aged↗
PubMed1995

Simultaneous expression of type IX collagen and an inhibin-related antigen in proliferative myoepithelial cells with pleomorphic adenoma of canine mammary glands.

To identify an alcian blue-positive component expressed in the early stage of mammary mixed tumor and to pursue the possible involvement of a tumorigenic inducing factor, monoclonal antibodies to type IX collagen were generated and used to investigate the immunohistochemical kinetics of type IX collagen expression by the myoepithelial cell-derived chondrocyte-like cells during the development of chondrometaplasia. We also examined the expression of inhibin-related antigen using antibodies to a synthetic peptide spanning amino acids 1-30 of the inhibin alpha chain. At the earliest stage of chondrometaplasia, where myoepithelial cells began to proliferate inside the basement membrane, the cells expressed type IX collagen together with an inhibin-related antigen which was immunoreactive with the anti-inhibin peptide antibodies. The expression of the inhibin-related antigen was also demonstrated in normal embryonic chondrocytes and myoblasts, but was much less strong in mature chondrocytes and myotubes, strongly suggesting that the inhibin-related antigen is involved in the development of chondrocytes and myoblasts from undifferentiated mesenchymal cells as well as proliferating myoepithelial cells as a chondro-progenitor cell in the mammary mixed tumor. The pathophysiological significance of type IX collagen expression as a possible cell marker of the progenitor cell in myoepithelial cell-related chondrometaplasia is also discussed.

Adenoma, Pleomorphic↗
PubMed1994

Fine structure of the anteromedial eye of the liphistiid spider, Heptathela kimurai.

BACKGROUND: The presence of efferent fibers in the anteromedial eye of liphistiid spiders kept in natural daily cycles of illuminance has been reported. However, this report is limited to innervation by the efferent fiber and daily rhabdomal changes, and there have been no detailed ultrastructural accounts of the eye. METHODS: The fine structure of this eye was examined by electron microscopy. RESULTS AND CONCLUSIONS: The eye consists of a cornea, a lens, a vitreous body, and a retina. The retina contains 13 or 14 receptor cells and glial cells. The rhabdoms are distal to the nuclei of the receptor cells. In the distal region of the receptive segment, the rhabdomeres lie in the center of the cell. In the middle region, anisomorphic rhabdoms formed by microvilli from adjacent cells are at the cell periphery. In the proximal region, the rhabdomeres are situated in the center of the cell. The ocellar nerve of the eye runs toward the protocerebrum and enters the posterior part of the first optic ganglion of the secondary eyes. Pigmented cells and nonpigmented cells are observed. The pigmented cells are located in the most lateral of the eye and cover the whole eye. The nonpigmented cells are located in the receptor cell bodies and extend to the origin of the ocellar nerve. They wind to form capillaries filled with electron-dense material. These structures are discussed in comparison with those of other spiders and other chelicerates.

Animals↗
PubMed1994

Effects of hydrocortisone and adrenaline on natural killer cell activity.

We have studied the effects of hydrocortisone and adrenaline on natural killer (NK) cell activity and on the distribution of circulating lymphocyte subpopulations in 30 patients undergoing elective partial laminectomy under general anaesthesia. The patients were allocated to receive adrenaline (group 1, n = 11), hydrocortisone and adrenaline (group 2, n = 11) or neither hydrocortisone nor adrenaline (group 3, n = 8). Group 1 and group 2 patients received local adrenaline infiltration during operation to reduce bleeding. The mean dose of adrenaline administered was 2.1 (SD 0.2) microgram kg-1. Group 2 received hydrocortisone 10 mg kg-1 i.v. after premedication. In groups 1 and 2, adrenaline produced an instantaneous increase in NK cell activity accompanied by a selective increase in circulating NK cells. The measurements returned to pre-infiltration levels within 120 min of administration of adrenaline. The effect of adrenaline in causing increased NK cell activity was not blocked by pre-administration of hydrocortisone. There was a significant decrease in the ratio of T-helper/inducer cells (CD4) to T-suppressor/cytotoxic cells (CD8) in all patients after induction of anaesthesia. In groups 1 and 3, the CD4/CD8 of anaesthesia. In groups 1 and 3, the CD4/CD8 cell ratio did not change significantly during operation. However, compared with groups 1 and 3, group 2 showed a significantly reduced CD4/CD8 cell ratio during operation. Therefore, these results suggest that even in cases of such severe stress that the immune response was depressed by increased serum cortisol concentrations, adrenaline-induced NK cell activity enhancement was preserved.

Adolescent↗