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Biomedical subjects

A Hayashi

Publications and source records attributed to A Hayashi.

At least 19 recordsLinked to original sources
PubMed1992

Structural elucidation of a novel phosphonoglycosphingolipid in eggs of the sea hare Aplysia juliana.

A novel phosphonoglycosphingolipid (AJPnGL) was isolated from eggs of the sea hare Aplysia juliana. The structure was determined to be Gal alpha 1-->2Gal beta 1-->4(2-aminoethylphosphonyl-->6)Glc beta 1-->1Cer by FAB/MS, 1H-NMR, hydrogen fluoride degradation, methylation analysis, partial acid hydrolysis and GC analysis of the component sugars, fatty acids and long-chain bases. The ceramide moiety of this lipid consisted of branched nonadeca-4-sphingenine and octadeca-4-sphingenine as main long-chain bases and palmitic acid and stearic acid as major fatty acids. Since the sugar chain (Gal alpha 1-->2Gal beta 1-->4Glc beta 1-->) and the ceramide moiety of AJPnGL were identical with those of the main neutral glycosphingolipid of eggs of A. juliana, the biosynthesis of AJPnGL may occur by the addition of 2-aminoethylphosphonate to the main neutral glycosphingolipid, Gal alpha 1-->2Gal beta 1-->4Glc beta 1-->1Cer.

Animals↗
PubMed1992

Studies on the chemical structure of neutral glycosphingolipids in eggs of the sea hare, Aplysia juliana.

Six neutral glycosphingolipids (GL-1-GL-6) were obtained from eggs of the sea hare (Aplysia juliana) and were characterized by FABMS, 1H-NMR, partial acid hydrolysis, methylation studies and GC analysis of the component sugars, fatty acids and long-chain bases. The following structures were determined to be Glc beta 1-1Cer (89%) and Gal beta 1-1Cer (11%) for GL-1, Glc beta 1-1Cer (47%) and Gal beta 1-1Cer (53%) for GL-2 having hydroxy fatty acids in the ceramide moiety, Gal beta 1-4Glc beta 1-1Cer for GL-3, Fuc alpha 1-2Gal beta 1-4Glc beta 1-1Cer for GL-4, Gal alpha 1-2Gal beta 1-4Glc beta 1-1Cer for GL-5 and GalNAc alpha 1-3(Gal alpha 1-2)Gal beta 1-4Glc beta 1-1Cer for GL-6. The fatty acid composition of each glycosphingolipid, except for GL-2, which contained 2-hydroxypalmitic acid, consisted of mostly saturated C16-C20 acids, especially palmitic acid and stearic acid. The long-chain bases of all glycosphingolipids consisted mainly of branched nonadeca-4-sphingenine and octadeca-4-sphingenine. GL-6, which was one of the major glycosphingolipids, may be a precursor of a series of phosphonoglycosphingolipids which have been isolated from the skin of A. kurodai.

Animals↗
PubMed1992

Neonatal congenital diaphragmatic hernia and extracorporeal membrane oxygenation.

OBJECTIVE: To describe the outcome of infants with congenital diaphragmatic hernia (CDH) presenting early who were referred for possible extracorporeal membrane oxygenation (ECMO). DESIGN: Retrospective descriptive study. SETTING: Neonatal Intensive Care Unit of the Royal Alexandra Hospital, Edmonton. PATIENTS: Fifteen infants referred to our program since its introduction, in February 1989; 13 received ECMO. The criterion for ECMO was the presence of an oxygen index of more than 40 on three occasions within 2 hours. INTERVENTION: ECMO was performed by means of cannulation of the right carotid artery and jugular vein for 111.0 hours on average. RESULTS: In 5 of the 13 infants who underwent ECMO the procedure was performed after surgical repair; all were successfully weaned off ECMO, and the cannula was removed without incident. In the remaining eight ECMO was started before surgical repair; of the six who received it during repair four ultimately survived. None of the previously described predictors of outcome for CDH, including diagnosis before 25 weeks' gestation (in six cases), were useful in determining the survival of the patients. Bleeding was the most common complication and cause of death. CONCLUSION: ECMO is associated with survival in infants with CDH who fail to respond to conventional therapy and who have a poor prognosis according to previously established criteria.

Extracorporeal Membrane Oxygenation↗
PubMed1992

Vascularized rib strut technique for repair of pectus excavatum.

A vascularized rib strut based on the anterior intercostal branch of the internal mammary artery was applied to provide rigid internal fixation of the chest wall after correction of pectus excavatum. The procedure is simple and has substantial advantages when compared with techniques using metallic struts or nonvascularized free rib grafts.

Adult↗
PubMed1992

A temperature-sensitive CHO-K1 cell mutant (tsTM13) defective in chromosome decondensation and spindle deconstruction in M phase.

A temperature-sensitive CHO-K1 cell mutant, tsTM13, exhibited a delayed cell cycle progression from metaphase to telophase at a nonpermissive temperature and was finally arrested from anaphase to telophase. Metaphase chromosomes were overcondensed and chromosome disjunction in anaphase was uncoordinated. In telophase, sister chromatids were segregated and cytokinesis was completed, but chromosome structure remained in a condensed state and the spindle was not deconstructed. The level of phosphorylation of histones H1 and H3 remained high in the later stages of mitosis and the activity of histone H1 kinase was also maintained at a high level. These results strongly suggest that the pleiotropic defects of tsTM13 cells in mitosis are associated with a lack of inactivation of activated histone H1 kinase.

Amino Acid Sequence↗
PubMed1992

Development of a highly cardioselective ultra short-acting beta-blocker, ONO-1101.

A novel, highly cardioselective ultra short-acting beta-blocker, ONO-1101, has been developed for application in the emergency treatment of tachycardia and better control of heart rate in surgery. This agent is approximately nine times more potent in beta-blocking activity in vivo and eight times more cardioselective in vitro than esmolol. This beta-blocking drug has a short duration of activity, enabling rapid recovery after cessation of administration if side effects occur. It can be used safely in patients suffering from acute heart disease and represents a major therapeutic advance in the treatment of heart disease.

Adrenergic beta-Antagonists↗
PubMed1992

[Assay of flow cytometry for the effect of cepharanthine on resistance to doxorubicin].

The biochemical activity of cepharanthine and the possible mechanism by which it reverses the resistance to doxorubicin in P388 leukemia cells were examined in vitro. The microfluorometric analysis of the cellular level of doxorubicin in drug-resistant cells showed that cepharanthine markedly enhanced the sensitivity of doxorubicin against resistant cells in the cellular level. Cepharanthine also enhanced the inhibitory effect of doxorubicin on the incorporation of thymidine into DNA in resistant cells. The analysis of DNA histogram obtained by flow cytometry showed that doxorubicin exerted its growth-inhibitory effect by blocking the cell cycle at the G2 phase in P388 cells. At higher concentrations, doxorubicin prolonged the S phase and inhibited cell cycle progression to the G2/M phase in cells. The treatment with cepharanthine potentiated these blocking effects induced by doxorubicin in cells. It seems that the modifications of the biological effect of doxorubicin by cepharanthine are due to the change of their ability to induce DNA damage in cells.

Alkaloids↗
PubMed1992

Triphenyltin-induced increase in the intracellular Ca2+ of dissociated mammalian CNS neuron: its independence from voltage-dependent Ca2+ channels.

To test the possibility that triphenyltin (TPT) increases the intracellular Ca2+ ([Ca2+]i) in neurons as found previously in thymocytes, the effect of TPT on [Ca2+]i was examined in rat cerebellar neurons by a flow-cytometer with fluorescent dyes. TPT at concentrations ranging from 3 x 10(-7) M to 1 x 10(-5) M dose-dependently increased the [Ca2+]i. The TPT-induced increase in [Ca2+]i was not attenuated by a Ca2+ channel blocker, suggesting that it was not dependent on voltage-dependent Ca2+ channels. As the concentration of external Ca2+ ([Ca2+]e) increased, TPT produced a more profound increase in the [Ca2+]i. However, the increase in the [Ca2+]i by TPT was observed even in nominally [Ca2+]e-free solution. These results suggest two possibilities. First, TPT may promote Ca(2+)-influx to the neuron. Secondly, TPT may affect the intracellular Ca-store sites. This study is relevant to the neurotoxicity of organotins because it has become progressively clear that sustained increases in the [Ca2+]i can activate various Ca(2+)-dependent degradative processes.

Animals↗
PubMed1992

Flow cytometric estimation of the effect of Ginkgo biloba extract on the content of hydrogen peroxide in dissociated mammalian brain neurons.

The effect of Ginkgo biloba extract (GBE) on the content of hydrogen peroxide was estimated in cerebellar neurons dissociated from rats, by means of a flow-cytometer and 2',7'-dichlorofluorescein (DCF) diacetate, a fluorescent dye for intracellular hydrogen peroxide. The GBE started to reduce the DCF fluorescence of the neuron at 0.1 microgram/ml to 0.3 microgram/ml. Further increases in the GBE concentration (up to 3 micrograms/ml) produced a dose-dependent decrease in the DCF fluorescence, suggesting that GBE reduces the content of hydrogen peroxide or suppresses the reactive oxygen species (ROS) formation of cerebellar neurons. The present technique may be useful for preliminary evaluations of agents affecting the ROS formation in mammalian brain neurons.

Animals↗
PubMed1992

Stereotactic radiosurgery using a linear accelerator.

A basic and clinical study of radiosurgery using the linear accelerator (Linac) system for unremovable deep-seated brain tumors is reported. A Komai stereotactic ring was used to locate the target coordinates. The patient was laid on the Linac treatment table and held in the head fixation system. Irradiation was given in five positions. The dose profile by film dosimetry and Rando phantom was satisfactory. Seventeen tumors in 14 patients were treated. Clinical or histological diagnoses were nine metastases, one benign and two malignant gliomas, one meningioma, and one craniopharyngioma. Tumor sizes were between 8 and 30 mm. Doses were between 12 and 30 Gy. Computed tomographic evaluation after 3 months of 12 tumors in 11 survivors showed one complete remission, three partial remission, six no change, and two partial deterioration. For progressive tumors, Linac radiosurgery results are excellent.

Adult↗
PubMed1992

The mechanism of action of serum immunosuppressive factor in Crohn's disease: it blocks the growth of mitogen-stimulated lymphocytes in early G1 phase through an inhibition of transferrin receptor expression.

The presence of serum immunosuppressive factor has recently been reported in patients with Crohn's disease. We investigated the mechanism of action of this immunosuppressive factor in vitro. The factor in serum fraction from patients with Crohn's disease had an inhibitory activity on the proliferation of phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMCs) from healthy volunteers. The growth of tumor cell lines, however, was not inhibited by the factor. While the factor did not influence the production of interleukin 2 (IL2) or the expression of IL2 receptor of PHA-stimulated PBMCs, it inhibited the expression of transferrin receptor. The effect of the factor on cell cycle of PHA-stimulated PBMCs was examined by flow cytometry analysis. The factor kept the cells in quiescent G0/G1 phase and decreased the number of cells in S phase. Prostaglandin E2, an immunosuppressive substance, may not participate in the inhibitory action of the factor, since indomethacin did not affect the inhibitory activity of the factor. These results suggest that the immunosuppressive factor in serum from patients with Crohn's disease is unique in the mechanism of inhibitory action and further clarification of this factor might contribute to the development of a new diagnostic assay for Crohn's disease and the elucidation of the pathogenesis of this disease.

Cell Cycle↗
PubMed1992

[Ultrastructural, immunohistochemical and immunoelectron microscopic studies on the transitional part of the trabecular meshwork and the ciliary muscle in human and porcine eyes].

The authors demonstrated the ultrastructure of the transitional portion of the human trabecular meshwork (TM) of the ciliary muscle (CM) by transmission electron microscopy, together with the porcine TM and CM, which have not been reported so far. In the transitional portion of the human eye, bundles of smooth muscle cells showed tapering in the anterior portion, and long slender processes of TM cells covered the outside of muscle bundles occasionally, in association with intervening nerve fibers. In the human transitional portion, there were many stick-like or irregular-shaped structures consisted of collagen fibrils. In the porcine eye, although the fine structure of the TM was similar to that of human TM, the shape of each porcine CM cell was irregular and their cytoplasm were invaginated into the adjoining cells, like herniation. In the immunohistochemical study, the positive immunoreactions were found in TM cells for vimentin, Schwann cells for S-100 and S-100b, and the CM cells for muscle (m)-actin and desmin in both species by using each antibody. Only the porcine TM cells were positive for S-100 and S-100b. In the human eye, smooth muscle-like cells similar to TM cells in the transitional portion were detected, and these cells were positive for m-actin. Moreover, the cells covering Schlemm's canal were positive for factor VIII and UEA-1. These immune positivities were confirmed at the ultrastructural level. These immunohistochemical reactions may be useful tools to evaluate cell at the light and electron microscopic levels in human and porcine TM and CM regions.

Actins↗
PubMed1992

[A suspected case of perforation of a lymph node into the bronchus during the treatment of adult hilar lymph node tuberculosis].

A 27-year old patient was diagnosed as having post-primary hilar lymph node tuberculosis. First being admitted to the hospital with a high fever, a chest x-ray examination revealed a swelling of the left hilar lymph nodes and a sputum smear tested positive for acid-fast bacilli. Neither regular clinical examination or investigation had reported abnormality. The acid-fast bacilli was successfully treated through treatment using INH RFP SM. However, after two months, swelling was observed in the right para-tracheal lymph nodes, Further, a bronchoscopic examination revealed polyp-like tumors at the left upper and lower bifurcation. The swelling of the para-tracheal lymph nodes was considerably reduced and the tumors non-existent after five months. These lymph node reactions could have likely been a part of the so called early exacerbation. The polyp-like tumors were not found during the bronchoscopy performed during admission to the hospital. It is therefore suspected that the cause was perforation of the hilar lymph node into the bronchus.

Adult↗
PubMed1992

[Intralobal sequestration in children--a new concept from the form of bronchial tree in sequestrated lung].

Twenty cases of the intralobal sequestration of the lung in children have been experienced. The age of the patients were from eleven days to fifteen years. Intralobal sequestration was classified into two groups, (central type and peripheral type) by the way of reconstruction of the bronchial tree in the sequestrated lung. In 8 cases of central type, the site of lesion was variable. The bronchial trees of the sequestrated lung were running toward the hilus of the normal lung but the bronchi of the affected area in the normal lung were absent. The aberrant arteries were muscular in histology, and the drainage veins were pulmonary vein. In 12 cases of peripheral type, the lesion was in segment 10 area in every cases. The bronchial trees of the sequestrated lung were running toward the pulmonary ligament where an aberrant artery came from, and B10 of the normal lung were patent. The aberrant arteries were elastic in histology, and the drainage veins were pulmonary and/or azygos vein. It is conceivable that the peripheral type is the real intralobal sequestration and the central type is the mixture of some other diseases.

Adolescent↗
PubMed1991

Novel phosphonoglycosphingolipids containing pyruvylated galactose from the nervous system of Aplysia kurodai.

We have reported the existence of a phosphonoglycosphingolipid containing a pyruvylated galactose, FGL-IIb, in nerve fibers of Aplysia kurodai (Araki, S., Abe, S., Ando, S., Kon, K., Fujiwara, N. & Satake, M. (1989) J. Biol. Chem. 264, 19922-19927). We have now isolated two other pyruvylated galactose-containing phosphonoglycosphingolipids, named FGL-V and FGL-IIa, from the nervous tissue of Aplysia, and characterized them as [3,4-O-(S-1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3[6'-O-(2- aminoethylphosphonyl)Gal alpha 1----2] (2-aminoethylphosphonyl----6) Gal beta 1----4Glc beta 1----1 ceramide and [3,4,O-(S-1-carboxyethylidene)] Gal beta 1----3GalNAc alpha 1----3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1----2]Gal beta 1----4Glc beta 11----ceramide, respectively. Their major aliphatic components are palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. Thus, the nervous system of Aplysia contains several pyruvylated phosphonoglycolipids.

Animals↗
PubMed1991

Occurrence of ceramide digalactoside as the main glycosphingolipid in the marine sponge Halichondria japonica.

The main glycosphingolipid of the sponge Halichondria japonica was isolated and its structure was determined to be ceramide digalactoside, Gal alpha 1----4Gal beta 1----1Cer, using FAB/MS, IR, 1H-NMR and chemical methods such as permethylation analysis and degradation techniques. The ceramide moiety was composed mainly of 4-hydroxy-iso-octadecasphinganine and 2-hydroxy-docosanoic acid. Interestingly, the branched long-chain bases were comprised of 70% total long-chain bases and 17.5% 4-hydroxy-anteiso-nonadecasphinganine. Ceramide monohexoside, consisting of galactosyl ceramide (81%) and glucosyl ceramide (19%), was also isolated as a minor component. The composition of the ceramide moiety was nearly the same as that of ceramide digalactoside.

Animals↗