Characterization of NK-2 binding sites in rabbit lung tissue.
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Animals↗
Biomedical subjects
H Yamamura
Publications and source records attributed to H Yamamura.
Phosphorylation sites of myelin basic protein by a catalytic fragment of non-receptor type protein-tyrosine kinase p72syk and comparison with those by insulin receptor kinase.
Myelin basic protein has been used as a model substrate for determination of substrate recognition motif of various protein kinases. In this report phosphorylated sites of bovine brain myelin basic protein were studied with a catalytic fragment of protein-tyrosine kinase p72syk. Three of four tyrosine residues in myelin basic protein were phosphorylated by this kinase. Major phosphorylated site was 134Y and minor phosphorylated sites were 68Y and 127Y. As the phosphorylation site by p56lck was only 68Y, the recognition motif of p72syk was quite different from that of p56lck. Furthermore, the fact that elution pattern on HPLC of the phosphopeptides obtained by insulin receptor kinase was different from that by p72syk suggested that the recognition motif of p72syk was also different from that of insulin receptor kinase. These results may suggest that each protein-tyrosine kinase has a specific substrate recognition motif.
Amino Acid Sequence↗
Association with B-cell-antigen receptor with protein-tyrosine kinase p72syk and activation by engagement of membrane IgM.
We have demonstrated that a 72-kDa non-receptor-type protein-tyrosine kinase (p72syk) was co-immunoprecipitated with membrane IgM in digitonin lysates of porcine tonsillar cells and was rapidly activated following the engagement of membrane IgM. This activation was occurred within 5 s, even in the presence of EGTA and 5,5'-dimethyl-bis-(O-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid as extracellular and intracellular Ca(2+)-chelating agents, respectively, as well as in the presence of the protein-kinase-C inhibitor, H-7. Additionally, genistein, a potent protein-tyrosine kinase inhibitor, was capable of reducing both IgM-stimulated Ca2+ mobilization and p72syk activation in a dose-dependent manner. These results indicate that p72syk is physically associated with the B-cell-antigen receptor, participating in antigen-mediated signal transduction in both a Ca(2+)-independent and protein-kinase-C-independent manners.
Animals↗
Protein-tyrosine kinase p72syk is activated by thrombin and is negatively regulated through Ca2+ mobilization in platelets.
Activation of platelets by thrombin results in a dramatic increase in tyrosine phosphorylation on multiple cellular proteins (Ferrell, J. E., and Martin, G. S. (1988) Mol. Cell. Biol. 8, 3603-3610; Golden, A., and Brugge, J. S. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 901-905; Nakamura, S., and Yamamura, H. (1989) J. Biol. Chem. 264, 7089-7091). However, none of the responsible protein-tyrosine kinase has been reported so far. We report here that p72syk, one of the non-receptor-type protein-tyrosine kinases, is activated following thrombin stimulation in blood platelets. Washed porcine platelets were stimulated by thrombin, and the activation of p72syk was assessed in an immunoprecipitation kinase assay. The activity of p72syk increased within 5 s, reached a maximum at 10 s, and decreased to a basal level within 60 s after 0.5 unit/ml thrombin stimulation. The amount of immunoprecipitated p72syk was not altered throughout the time course. This activation was greatly enhanced in a dose-dependent manner and was completely canceled by the pretreatment of platelet suspension with hirudin, a specific antagonist of thrombin. In the Ca(2+)-depleted condition both extra- and intracellularly, the activation of p72syk was still persistent; in contrast, the deactivation process was completely abrogated even at 120 s after thrombin stimulation. In addition, the replenishment of Ca2+ resulted in a similar deactivation pattern as seen in the Ca(2+)-rich condition. Furthermore, this deactivation was also canceled by the pretreatment of platelets with W7, a calmodulin antagonist, as well as ML9, a myosin-light-chain kinase inhibitor. These results indicate that p72syk can be a responsible enzyme to the protein-tyrosine phosphorylation events following the platelet activation by thrombin and may be negatively regulated by Ca2+ in a calmodulin-dependent manner, inter alia myosin light-chain kinase, in thrombin-stimulated platelets.
Animals↗
Crystal structures of Boc-D- and L-Iva-L-Pro-OBzl: unturned conformation of Aib-Pro sequence unaffected by replacement of Me with Et in Aib.
The crystal structures of the isovaline (Iva) containing dipeptides, Boc-D-Iva-L-Pro-OBzl and Boc-L-Iva-L-Pro-OBzl, were determined by x-ray diffraction. The diastereomeric peptides were shown to adopt unturned conformations closely similar to each other (phi Iva 52 degrees, psi Iva 46 degrees, phi Pro -65 degrees, and psi Pro 143 degrees for D-Iva-L-Pro sequence and phi Iva 52 degrees, psi Iva 44 degrees, phi Pro -63 degrees, and psi Pro 148 degrees for L-Iva-L-Pro sequence). The Pro ring of each peptide was in C gamma-endo conformation. The unusually large angle CIva-NPro-C delta Pro values (131 degrees in both peptides) were observed, that was due to steric repulsion between the delta-methylene of Pro and the alkyl side chain of Iva residue. These conformations were essentially the same as that of the corresponding alpha-aminoisobutyric acid (Aib)-containing peptide Boc-Aib-L-Pro-OBzl. The result has demonstrated that replacement of either one of the two methyl groups of the Aib residue in Boc-Aib-L-Pro-OBzl with an ethyl group does not cause any significant change in the unturned conformation of the dipeptide.
Aminoisobutyric Acids↗
Involvement of protein kinase C in nuclear migration during compaction and the mechanism of the migration: analyses in two-cell mouse embryos.
Compaction and nuclear migration occur in mouse embryos at the late eight-cell stage. It has been reported that activators of protein kinase C (PKC) increase adhesion of cells at the two-cell, four-cell, and uncompacted eight-cell stage. We report here that nuclear migration followed the increased adhesion of cells in such embryos when they were treated with PKC activators. These cellular events resembled those in normal embryos at the late eight-cell stage and were blocked by sphingosine, a PKC inhibitor. The responses were proportional to the dose of the PKC activator. Molecular analogues of the PKC activators, which do not affect PKC, did not induce these events. These results suggest an important role for PKC in initiation of nuclear migration as well as in compaction. Experiments were also conducted to identify the source of the mechanical force that moves the nucleus. Nuclear migration was suppressed in embryos pretreated with colchicine. Calmodulin is known to have effects on Ca(2+)-induced assembly and disassembly of microtubules. The calmodulin antagonists W-7 and W-5 suppressed nuclear migration. These results suggest that microtubules are essential for the migration and that nuclei are migrated via the Ca(2+)-induced, calmodulin-mediated assembly and disassembly of the microtubule networks. Together, these results obtained with PKC activators/inhibitor, colchicine, and calmodulin antagonists suggest that nuclear migration is mediated by increases in PKC activity, requires intact microtubules, and is accompanied by PKC-dependent increases in cell-cell adhesion.
Animals↗
Granule cells and the development of synapses with mossy fibres in the cerebellum of the jaundiced Gunn rat.
The development of granule cells and the formation of synapses with mossy fibres were investigated in cerebella from jaundiced (j/j) Gunn rats with hereditary hyperbilirubinemia. The external granular layer was thinner than that in cerebella from heterozygous (+/j) Gunn rats without hyperbilirubinemia on days 12 and 15 after birth, and it had disappeared in places by day 18. Migrating granule cells decreased in number from days 12 to 18. In the internal granular layer, the paucity of granule cells became apparent on day 12 and a reduction in the number of cells was prominent from day 18 onward. More degenerating cells were found in j/j cerebella than in +/j cerebella on days 12 and 15. Mossy fibre-granule cell synapses (glomeruli) were immature in appearance in j/j and +/j cerebella from days 7 to 12; small, roundish mossy fibre terminals were in contact with a few dendrites of granule cells. After day 18, the glomeruli were mature in terms of shape in +/j cerebella. By contrast, the mossy terminals remained small and roundish, and the granule cell dendrites that surrounded the mossy terminals did not increase in number nor develop digitiform branches in j/j cerebella. The mossy terminals were partially surrounded by glial processes and were occasionally surrounded by large dendrites of Golgi cells, which made multiple synaptic contacts. Some degenerating mossy terminals were present from days 18 to 30. These anomalous glomeruli may be caused by insufficient synaptic contacts with granule cells.
Aging↗
Differences in the effects of treatment of uncompacted and compacted mouse embryos with phorbol esters on pre- and postimplantation development.
Differences are described in the effects of treatment of preimplantation mouse embryos with low levels (0.01-1 nM) of phorbol myristate acetate (PMA), during three different periods of a 48-h culture from the 2-cell stage, on pre- and postimplantation development. Treatment of embryos with PMA for 48 h (first group) or 24 h (second group) from the 2-cell stage caused premature cavitation (prior to the 16-cell stage) and it also reduced the size and alkaline phosphatase (ALPase) activity of inner cell masses (ICMs), as well as the numbers of cells in blastocysts, in a dose-dependent manner. Treatment of early morulae with PMA for 24 h (third group) did not have the above mentioned effects on embryos but inhibited the formation and subsequent enlargement of the blastocoel. The blastocysts that were allowed to develop in the three treatment groups were examined for postimplantation development. Implantation was unaffected in all groups. The survival rate after implantation was low in the first and second groups but relatively high in the third group. The results indicate that an embryo exposed to PMA for 24 h from the 2-cell stage forms a premature blastocoel, and, in such an embryo, quantitative and qualitative differentiation into the ICM is blocked but qualitative differentiation into trophectoderm is uninhibited. Consequently, the embryo can implant but does not survive for a long time. When embryos were exposed to PMA for 24 h from the early morula stage, the formation and enlargement of the blastocoel were inhibited even though the treatment had a minimal effect on other developmental events.(ABSTRACT TRUNCATED AT 250 WORDS)
Alkaline Phosphatase↗
Important role of peptide leukotrienes (p-LTs) in the resting tonus of isolated human bronchi.
The quality of the resting tonus in isolated human bronchi was investigated using a peptide leukotriene (p-LT) antagonist, a 5-lipoxygenase inhibitor and others. (E)-2,2-Diethyl-3'-[2-[2-(4-isopropyl)-thiazoyl]ethenyl]succina nilic acid sodium salt (MCI-826), a newly synthesized compound that is a highly selective antagonist to LTD4 and LTE4, markedly relaxed the isolated human bronchi at low concentrations. A selective and competitive arachidonate 5-lipoxygenase inhibitor, 2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone (AA-861), also potently lowered the tonus. In addition, a large amount of spontaneously formed p-LTs was detected in the isolated human bronchial tissue as well as the lung parenchymal tissue. The isolated human bronchi responded to indomethacin treatment with contractions and the acceleration of p-LT formation. Atropine, an anticholinergic; mepyramine, an antihistaminic; and OKY-046, a thromboxane synthetase inhibitor, all showed no effect on the resting tonus. Taking into consideration the high responsiveness of the human airway smooth muscle to p-LTs and the present results, which were different from those on isolated guinea pig tracheas, it is strongly suggested that the spontaneously formed p-LTs largely participate in the resting tonus of the majority of isolated human bronchi.
Animals↗
Dimaprit, a histamine H2-agonist, inhibits anaphylactic histamine release from mast cells and the decreased release is restored by thioperamide (H3-antagonist), but not by cimetidine (H2-antagonist).
Whether anaphylactic histamine release from rat peritoneal mast cells is influenced by betahistine, a histamine H1-receptor agonist/H3-antagonist, and dimaprit, an H2-agonist, was examined. Treatment with dimaprit at 6 and 60 microM for 20 min significantly inhibited the anaphylactic histamine release, whereas betahistine at up to 80 microM under the same conditions did not affect it. Treatment with dimaprit at 6 and 60 microM for 1 to 20 min and for 5 to 20 min, respectively, caused a time-dependent inhibition of the release, but up to 30 min treatment with 8 and 80 microM betahistine had no effect. The decreased histamine release induced by dimaprit was recovered by neither mepyramine nor cimetidine. However, thioperamide, an H3-selective antagonist, dose-dependently restored the diminished release. From these results, the inhibition of anaphylactic histamine release by dimaprit is not produced by the stimulation of H2-receptors, but involves the stimulation of H3-like receptors or H3-subtype receptors, which are distinct from the H3-receptors located in brain, and suggests that the receptor plays an important role in the negative feedback regulation of histamine release.
Anaphylaxis↗
Disturbance of neuronal migration in mouse cerebral cortex by low-dose gamma-radiation.
We show that neuronal migration is disturbed by low-dose gamma-radiation of 0.24 Gy in the developing cerebral cortex of mice and suggest that neuronal progenitors in the S phase of mitosis are more sensitive than those in the G1/G0 phase. To pulse-label the fetal cells pregnant Slc:ICR mice were injected with bromodeoxyuridine (BrdU) at 10.00 pm on day 16 of pregnancy or at 9.30 am on day 17. The mice then were exposed to 0.24 Gy gamma- or sham-irradiation at 10.00 am on day 17 of pregnancy. At the time of exposure cells labeled on day 16 were regarded as having completed mitosis, and those labeled on day 17 as being in the S phase. Cell death in the fetal ventricular zone after exposure was negligible. Dams were allowed to give birth and rear their litters. Brain samples obtained from offspring on the 2nd day after birth and at 6 weeks of age were used for the immunohistochemical examination of BrdU-labeled cells. Labeled cells remaining in the ventricular zone were significantly more numerous in irradiated animals than in sham-exposed ones on the 2nd day after birth, in mice treated prenatally with BrdU on day 17 of pregnancy; whereas, mice treated with BrdU on day 16 showed no statistically significant difference. At 6 weeks of age, in both groups most of the labeled cells were present in layers II-III of the SmI cerebral cortex. But, in the irradiated animals the labeled cells in these layers were significantly fewer and those in layers IV-VI more numerous than in the sham-exposed mice in both group treated with BrdU on day 16 or 17.
Animals↗
Effects of rokitamycin on bilirubin-albumin binding: a study in vitro.
The effects of rokitamycin, a macrolide antibiotic, on the binding of bilirubin to albumin were examined in vitro using blood plasma from young rats with hyperbilirubinemia, bilirubin-supplemented serum separated from human cord blood, and the human serum from a newborn infant with icterus gravis neonatorum. Rokitamycin at concentrations from 1 to 500 micrograms/ml (the entire range over which experiments could be conducted) had little or no effect on the concentration of unbound bilirubin in any of the incubation mixtures used. This result suggests that rokitamycin has no effect on the binding of bilirubin to albumin.
Animals↗
Double-masked comparative study of UF-021 and timolol ophthalmic solutions in patients with primary open-angle glaucoma or ocular hypertension.
A double-masked comparative clinical study of UF-021 (Rescula), a unique prostaglandin-related compound, was carried out at 18 centers with timolol maleate 0.5% ophthalmic solution as an active reference drug. After a wash-out period, UF-021 (0.12%) or timolol (0.5%) was given topically twice a day for 12 weeks to 158 patients with primary open-angle glaucoma or ocular hypertension, in a randomized double-masked manner. Both groups showed a significant reduction in intraocular pressure from the second week to the end of the study. In overall improvement rating, 91.4% of the cases (64/70) in the UF-021 group and 88.3% (68/77) in the timolol group were judged to be "Extremely improved" or "Improved". Five and 4 cases reported having side effects in the UF-021 and timolol groups, respectively, but none of the cases required any change or discontinuation of treatment. While UF-021 did not affect blood pressure, both systolic and diastolic blood pressures in the timolol group were significantly decreased. These results suggest that UF-021 (0.12%) has the potential to lower intraocular pressure equivalent to timolol (0.5%), while having no effect on cardiovascular functions.
Administration, Topical↗
An ataxic mutant rat with dilute coat color.
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Animals↗
[Vanishing tumor thrombus in IVC after oral administration of UFT and TAE in a patient with HCC; a case report].
A 74-year-old man was diagnosed as hepatocellular carcinoma (HCC) in the area of S6-7 with tumor thrombus continuously developed from hepatic vein to inferior vena cava (IVC). AFP value remained high despite two transcatheter arterial embolizations with adriamycin, mitomycin and Lipiodol (Lp-TAE). The AFP value gradually decreased two weeks after oral administration of UFT. Nine months after, the AFP level was 26.4 ng/ml and the tumor thrombus in the IVC disappeared. The size of the main tumor did not change. This case suggests Lp-TAE and UFT are useful for suppressing the growth of the main tumor and to extinguish the tumor thrombus.
Aged↗
Cerebellar hypoplasia in the hyperbilirubinemic Gunn rat: morphological aspects.
Gunn rats, a mutant strain of rats, suffer from autosomal recessive hyperbilirubinemia. The homozygotes (j/j) develop jaundice soon after birth and often exhibit kernicterus and cerebellar hypoplasia that are due to bilirubin. Therefore, j/j Gunn rats have been used as an animal model of bilirubin encephalopathy, as well as of neonatal hyperbilirubinemia. In this review, we discuss morphological aspects of the cerebellar hypoplasia that is due to bilirubin and describe the relationship between plasma bilirubin levels and cerebellar hypoplasia, as well as the pathogenesis of cerebellar hypoplasia, including abnormal histogenesis of the cerebellar cortex, abnormalities associated with Purkinje cells and abnormal synaptogenesis in j/j Gunn rats.
Animals↗
[A double-blind dose ranging study of weekly subcutaneous administration of rHuEPO (KRN5702) on post-phlebotomy anemia of patients scheduled for predeposit autologous blood transfusion (multicenter late PhII study)].
Preoperative blood reservation for autologous blood transfusion generally causes anemia. We performed a double blind controlled study to determine the optimal dose of subcutaneous rHuEPO (recombinant human erythropoietin, KRN5702) for preventing preoperative anemia due to blood reservation. Patients received KRN5702 subcutaneously once a week in a doses of 12000, 24000 or 36000 IU by a double blind technique. After storage of 1200 ml of their own blood right before surgery, their hemoglobin (Hb) averaged about 1 and was about 0.5 g/dl lower than the level before administration of KRN5702 in doses of 12000 and 24000 IU, respectively. This fall was significant. In patients receiving KRN5702 in a dose of 36000 IU, the level of Hb rose instead of a fall; Hb immediately before surgery was 1.1% higher than that before administration which, however, was not significant. This elevation indicates a possibility of abnormal elevation of Hb at this dose. The mean Hb value right before surgery was significantly lower in patients receiving 12000 IU KRN5702 than in patients of the other two groups. The recovery rate of Hb was an indicator to reflect improvement of anemic conditions, and increased as the dose increased after the blood reservation. The rate in the 12000 IU group was significantly lower than that in the other two groups; there was not much difference between the other two rates. We estimated that to reserve 1200 ml of autologous blood, 24000 IU of KRN5702 is adequate but not excessive. One patient receiving 24000 IU showed side effects including an elevation of body temperature, rash, and edema.
Adult↗
[The effects of hyperventilation upon the spinal pain modulating system].
The purpose of this study is to investigate the effects of hyperventilation on the wide dynamic range (WDR) cell of the dorsal horn of the feline lumbar spinal cord. Cats received midcollicular decerebration and lumbar laminectomy. The spinal cord was transected at T12-L1. WDR cells were sampled with microelectrode at the depth of 2,000 microns from the cord dorsum. Following the control period with PaCO2 of 35-45 mmHg, respiratory rate and tidal volume were adjusted to make a level of hypocapnia as low as 20-25 mmHg. The recovery of cell activity was followed when normocapnia was restored. Hypocapnia with PaCO2 of 25-30 mmHg and 20-25 mmHg suppressed the activity of WDR cell significantly. At PaCO2 of 25-30 mmHg, the spontaneous activity was suppressed for about 20% and evoked activity for 27%. At PaCO2 of 20-25 mmHg, the spontaneous activity was suppressed for about 50% and evoked activity for 33%. The results suggest that the hyperventilation has suppressive effects on single-unit activity of WDR cell.
Action Potentials↗