Search PubMed⌕ Search

Biomedical subjects

S Okuno

Publications and source records attributed to S Okuno.

At least 145 records · Page 8Linked to original sources

[The influence of local anesthetics on human leukocyte functions studied by micro whole blood collection and flowcytometry].

The influence of local anesthetics (pure bupivacaine and lidocaine with no preservative) on human leukocyte functions was examined. (a) The effect of bupivacaine on the phagocytosis of granulocyte was studied by bioassay. (b) The effect of lidocaine on the appearance of iC3b receptor (CR3) of granulocyte and monocyte (which is an important cell-adhesion-factor) was examined using flowcytometry. (c) The influence of lidocaine on phagocytosis of granulocyte and monocyte and on respiratory burst of granulocyte was examined using flowcytometry. (d) The influence of lidocaine on phagocytosis and that on respiratory burst were compared. These studies revealed that both phagocytosis and respiratory burst were inhibited by lidocaine, and the inhibition of respiratory burst was stronger than the inhibition of phagocytosis by local anesthetics' immunosuppressive effects. It was concluded that the balance of immunosuppressive action due to antimicrobial action and bactericidal ability of local anesthetics determined the occurrence of local bacterial infection.

Anesthetics, Local↗

A novel highly specific and potent inhibitor of calmodulin-dependent protein kinase II.

A novel synthetic peptide AIP (autocamtide-2-related inhibitory peptide), a nonphosphorylatable analog of autocamtide-2, was found to be a highly specific and potent inhibitor of calmodulin-dependent protein kinase II (CaM-kinase II). It was 50 and 500 times more potent than CaMK-(281-302Ala286) and KN-93, respectively, under the assay conditions used. The inhibition was unaffected by the presence or absence of Ca2+/calmodulin, and it was competitive with autocamtide-2 and noncompetitive with syntide-2. AIP (1 microM) completely inhibited CaM-kinase II activity, but did not affect cyclic AMP-dependent protein kinase, protein kinase C, calmodulin-dependent protein kinase IV, and unidentified protein kinases occurring in a rat brain extract. These results indicate that AIP is a useful tool for studying the physiological roles of CaM-kinase II.

Amino Acid Sequence↗

Cloning, sequencing and expression of a novel cDNA encoding human vacuolar ATPase (14-kDa subunit).

A cDNA encoding the 14-kDa subunit of vacuolar ATPase was cloned from human fetal brain. The sequence was composed of 680 nucleotides containing an open reading frame of 357 nucleotides. The deduced peptide sequence consisted of 119 amino acid residues with a calculated molecular weight of 13,369 Da and a pI of 5.19. Overall, this amino-acid sequence was respectively 69% and 70% identical to those of Manduca sexta and Drosophila melanogaster 14-kDa subunits, although the two representatives of Class Insecta were remarkably similar to one another (91% identity). Three regions in particular (the N-terminal, amino acids 5-36; the middle, residues 58-68; and the C-terminal, residues 88-118) were highly conserved. Hence, we think that the 14-kDa subunits have evolved from the same ancestral gene, and that the three conserved regions are important for the structure and function of vacuolar ATPase. A single 0.8-kb band was detected in various human tissues by Northern blot analysis. Since the human 14-kDa subunit is expressed ubiquitously, it might be a housekeeping protein. A separate transcript found in the cDNA library lacked a 6-bp segment in the 5' non-coding region (nucleotides -40 to -35) and also carried a 23C to T (8Thr to Ile) point mutation in the coding region; these minor differences likely reflected normal polymorphism.

Amino Acid Sequence↗

An immunohistochemical study of Ca2+/calmodulin-dependent protein kinase IV in the rat central nervous system: light and electron microscopic observations.

We observed the distribution pattern of Ca2+/calmodulin-dependent protein kinase IV in rat brain and spinal cord using an immunohistochemical method by light and electron microscopy. Particularly strong immunoreactivity was detected in the telencephalic structures such as the olfactory bulb, cerebral cortex, hippocampal formation, caudate-putamen, most nuclei of the dorsal thalamus and the granule cell layer of the cerebellum. Relatively weak staining was observed in the amygdaloid body, some neuron groups of the brainstem reticular formation, the inferior olivary nucleus and the posterior horn of the spinal cord. Immunohistochemical reactivity was not detected in the globus pallidus, substantia nigra, sensory and motor nuclei of the cranial nerves, or in the spinal cord anterior horn. Overall, the distribution of Ca2+/calmodulin-dependent protein kinase IV-like immunoreactivity broadly paralleled the sites of expression of signals for messenger RNA of this enzyme. At the subcellular level, Ca2+/calmodulin-dependent protein kinase IV-like immunoreactivity appeared exclusively in the nuclei of neurons in the various brain regions, and immunopositive reactivity, although less strong, was also observed in dendritic processes, as well as on the granular endoplasmic reticulum in neuronal somata in these areas. Axon terminals, however, did not show immunoreactivity. These studies demonstrate that Ca2+/calmodulin-dependent protein kinase IV-like immunoreactivity is distributed widely in the central nervous system. The significance of the localization of this enzyme in nuclei is discussed in relation to gene expression.

Animals↗

Decreased expression of the GLUT4 glucose transporter protein in adipose tissue during pregnancy.

Insulin resistance involves impaired activities of the glucose transport system in insulin target tissues. We therefore investigated the GLUT4 glucose transporter protein in adipose tissues from the pregnant women with normal glucose tolerance and from women with gestational diabetes mellitus, and compared these to nonpregnant women. Three groups of women were studied: nonpregnant women with normal glucose tolerance (N = 6), pregnant women with normal glucose tolerance (N = 6, gestational week 38.0 +/- 0.3), and pregnant women with gestational diabetes mellitus (N = 3, gestational week 38.6 +/- 0.3). The abdominal subcutaneous adipose tissues obtained from each group were subjected to analysis of the GLUT4 glucose transporter protein. The presence of the GLUT4 glucose transporter protein in the three groups was quantitatively determined by Western blot analysis of detergent-soluble adipose tissue extracts using anti-GLUT4 antibody. GLUT4 glucose transporter protein concentration in the adipose tissue of pregnant women were significantly lower than that in nonpregnant women, and this difference was more profound in women with gestational diabetes mellitus. We demonstrated that the content of GLUT4 protein was decreased in adipose tissue from normal pregnancy compared to nonpregnant women.

Adipose Tissue↗

Full activation of brain calmodulin-dependent protein kinase IV requires phosphorylation of the amino-terminal serine-rich region by calmodulin-dependent protein kinase IV kinase.

Rat brain calmodulin-dependent protein kinase IV (CaM-kinase IV) was activated approximately 20 to 30-fold by incubation with CaM-kinase IV kinase purified from rat brain under the Ca2+/calmodulin-dependent phosphorylation conditions. When CaM-kinase IV was incubated without CaM-kinase IV kinase, no significant activation was observed, indicating that the marked activation of CaM-kinase IV occurred as a result of the action of CaM-kinase IV kinase. More than 3 mol of phosphate were incorporated into 1 mol of the enzyme after incubation with CaM-kinase IV kinase at 30 degrees C for 20 min, but the activation occurred upon the initial incorporation of 1 mol of phosphate. The rate of the initial phosphorylation increased when the amount of CaM-kinase IV kinase added into the reaction mixture increased, but the rate of phosphorylation following the initial phosphorylation did not increase, suggesting that the initial phosphorylation was catalyzed by CaM-kinase IV kinase, and that subsequent phosphorylation was catalyzed by CaM-kinase IV itself activated by CaM-kinase IV kinase. The initial phosphorylation occurred in the amino-terminal serine-rich region of CaM-kinase IV. Kinetic analysis revealed that the increase in the activity upon phosphorylation was due mainly to an increase in the Vmax values.

Amino Acid Sequence↗

Inactivation of Ca2+/calmodulin-dependent protein kinase IV by Ca2+/calmodulin and restoration of the activity by Mg2+/EGTA.

The activity of calmodulin-dependent protein kinase IV (CaM-kinase IV) was progressively decreased by incubation at 30 degrees C with calmodulin in the presence of Ca2+, becoming one-half to one-fifth of the original activity within several minutes. The amount of calmodulin necessary to produce the maximal inactivation was approximately 1 mol for 1 mol of the enzyme. The inactivation of CaM-kinase IV by Ca2+/calmodulin was prevented by ATP in the presence of Mg2+, but such protection was not observed with either of the two alone or with a peptide substrate such as syntide-2. The activity of the calmodulin-inactivated enzyme was increased by incubation at 30 degrees C with Mg2+ in the presence of EGTA, being completely restored to the original level within several minutes, indicating that the Ca2+/calmodulin-induced inactivation of the enzyme was not due to irreversible denaturation of the enzyme. Both the inactivation of CaM-kinase IV by Ca2+/calmodulin and the restoration of its activity by Mg2+/EGTA were time- and temperature-dependent reactions. Kinetic analysis revealed that the alterations of the enzyme activity were due mainly to changes in Vmax of the enzyme.

Animals↗

Comparison of Ca2+/calmodulin-dependent protein kinase IV from rat brain, expressed in insect cells, and expressed in Escherichia coli.

Calmodulin-dependent protein kinase IV (CaM-kinase IV) is thought to play crucial roles in the functioning of Ca2+ in the central nervous system and immune system, and the regulation of its activity is therefore very important. Recombinant CaM-kinase IV is invaluable for studies of its regulatory mechanism, because of its large-amount availability and ready site-specific mutagenesis. In the present study, rat CaM-kinase IV was expressed in Sf9 cells and Escherichia coli, and the kinetic properties were examined with syntide-2 and peptide-gamma as substrates. The recombinant enzymes were produced highly efficiently, comprising as much as about 15% of the total protein in Sf9 cells and 9% in E. coli. The brain enzyme shows two Km values for syntide-2 in the presence of Ca2+/calmodulin, but the recombinant enzymes showed normal kinetic behavior. The brain enzyme and Sf9 enzyme showed Km values for peptide-gamma of 53 and 82 microM, respectively, but the Km of the E. coli enzyme was as high as 1.7 mM, in the presence of Ca2+/calmodulin. Thus, the three enzymes differed in their kinetic properties, but all the three were markedly activated upon incubation with CaM-kinase IV kinase under the Ca2+/calmodulin-dependent protein phosphorylation conditions.

Amino Acid Sequence↗

Adhalin gene mutations in patients with autosomal recessive childhood onset muscular dystrophy with adhalin deficiency.

Homozygous adhalin gene mutations were found in three patients from two consanguineous families with autosomal recessive childhood onset muscular dystrophy. Muscle biopsies from patients in each family showed complete absence of adhalin. Sequencing of adhalin cDNA prepared from skeletal muscle by reverse transcription PCR demonstrated a cytosine to thymidine substitution at nt 229 in the patient in family 1 and an adenine to guanine substitution at nt 410 and a 15-base insertion between nt 408 and 409 in the two patients in family 2. Sequencing of genomic DNA prepared from peripheral blood leukocytes by PCR confirmed these mutations. The parents in each family were found to be heterozygous for the respective mutations. These adhalin gene mutations are presumed to be responsible for the absence of adhalin in the skeletal muscle. Adhalin deficiency likely causes disruption of the muscle cell membrane, resulting in dystrophic changes in the skeletal muscle similar to dystrophin deficiency in Duchenne muscular dystrophy.

Adult↗

Synthesis of carboxymethylpullulan-peptide-doxorubicin conjugates and their properties.

The amino group of doxorubicin (DXR) was found to be bound to the carboxyl group of carboxymethylpullulan (CMPul) either directly or through tetrapeptide spacers, including Gly-Gly-Phe-Gly, Gly-Phe-Gly-Gly and Gly-Gly-Gly-Gly. These conjugates had DXR contents of 6.1-7.1%, with the degree of substitution of carboxymethyl groups being 0.6 per sugar moiety. These conjugates associate in phosphate-buffered saline (PBS) (pH 7.4), forming micelles with hydrophobic DXR inside and hydrophilic CMPul on the outside. The amounts of DXR released from the conjugates in the presence of rat liver lysosomal enzymes were determined by HPLC. The rate of the drug release differed among the conjugates tested. CMPul-DXR conjugate bound through Gly-Gly-Phe-Gly released 35% of its DXR over 24 h. On the other hand, CMPul-DXR conjugate without spacer released no free DXR. The antitumor effect of each conjugate in rats bearing Walker 256 was studied by monitoring the tumor weights after a single intravenous injection. Compared with DXR, CMPul-DXR conjugates bound through Gly-Gly-Phe-Gly and Gly-Phe-Gly-Gly spacers significantly suppressed the tumor growth, while CMPul-DXR conjugate bound through Gly-Gly-Gly-Gly showed less antitumor effect than DXR. CMPul-DXR conjugate bound through Gly-Gly-Gly-Gly showed less antitumor effect than DXR. CMPul-DXR conjugate without spacer showed no in vivo antitumor effect even at a dose equivalent to as much as 20 mg/kg of DXR.

Amino Acid Sequence↗

Biological activities of 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3 on human promyelocytic leukemic HL-60 cells: effects of fetal bovine serum and of incubation time.

The hexafluorinated vitamin D3 analog, 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3[F6-1,25-(OH)2D3] is more potent than 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] regarding various physiological effects. When the biological potencies of vitamin D3 analogs were assessed 24 h after the addition by the induction of 24-hydroxylation activity in the human promyelocytic leukemia cell line, HL-60,F6-1,25-(OH)2D3 was 6 times as potent as 1,25-(OH)2D3 in a medium containing 5% fetal bovine serum. When the cells were cultured in a serum-free medium, F6-1,25-(OH)2D3 was only equipotent to 1,25-(OH)2D3. Considering a previous report demonstrating a weaker binding of F6-1,25-(OH)2D3 to serum vitamin D-binding protein (DBP) than 1,25-(OH)2D3, it seems that the resultant greater free fraction of F6-1,25-(OH)2D3 might account for its greater activity in a serum-containing medium. As assessed by the suppression of cell proliferation and the induction of cell differentiation along the monocyte/macrophage pathway which requires as long as 96 h for their assessment, the potency ratio of F6-1,25-(OH)2D3 to 1,25-(OH)2D3 increased as the levels of fetal bovine serum increased. It was of great interest that F6-1,25-(OH)2D3 was still significantly more potent than 1,25-(OH)2D3 even in a serum-free medium. Together with the data indicating the equipotency of F6-1,25-(OH)2D3 and 1,25-(OH)2D3 in the induction of 24-hydroxylation activity, it was suggested that decreased metabolic inactivation might contribute in part to the higher potency of F6-1,25-(OH)2D3 in the long-term effect.

Animals↗

[Cerebral aneurysms associated with von Recklinghausen neurofibromatosis: report of two cases].

The authors reported two cases of aneurysms associated with von Recklinghausen's neurofibromatosis. The first case, a 60-year-old woman was referred to our hospital because of disturbance of consciousness and right hemiparesis of acute onset. On admission, she was almost alert but developed right hemiparesis and lower cranial nerve palsy. Computed tomographic (CT) scanning and magnetic resonance imaging (MRI) demonstrated a huge mass compressing the brain stem and another mass lesion in the suprasellar cistern. Cerebral angiography disclosed left vertebral and left internal carotid artery giant aneurysms. Since she suffered respiratory distress because of aspiration pneumonia, conservative therapy was carried out. However, she developed cardiac arrest suddenly and died fourteen days after admission. On autopsy, it was shown that the left sided medulla oblongata had necrosis due to compression by the giant aneurysm and that the hemorrhagic infarction of the left cerebellar hemisphere was caused by a thrombus from the giant aneurysm of the left vertebral artery. The second case, a 40-year-old woman presented a disturbance of consciousness. A CT scanning demonstrated subarachnoid hemorrhage with a thick hematoma in the left sylvian fissure. An aneurysm at the junction of the right internal carotid artery and the posterior communicating artery was found, while the left middle cerebral artery was shown to be normal on cerebral angiography. Additionally an arteriovenous fistula of the left vertebral artery was found. Although no aneurysm was seen in the territory of the left internal carotid artery, left sided craniotomy was performed based on the CT findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

The heterogeneity of whole islet cell cytoplasmic antibodies evidenced by absorption test with glutamic acid decarboxylase.

A recent report identified two islet cell cytoplasmic antibody subclasses using an immunohistochemical method. The islet cell cytoplasmic antibody subclass which reacts with only Beta-cells was termed 'Beta-cell islet cell cytoplasmic antibodies' and another islet cell cytoplasmic antibody subclass which reacts with Beta and non-Beta cells was called 'whole islet cell cytoplasmic antibodies'. The whole islet cell cytoplasmic antibody reactivity with pancreatic islets has been shown not to be abolished by pre-incubation with rat brain homogenate. In this study, we examined the inhibitory effect of purified glutamic acid decarboxylase to islet cell cytoplasmic antibody reactivity among whole islet cell cytoplasmic antibodies and assessed the heterogeneity of islet cell cytoplasmic antibodies. Auto-antibodies to 64,000 Mr islet cell protein (64 K antibodies) were also determined by conventional method. Sera from 17 Type 1 (insulin-dependent) diabetic patients containing whole islet cell cytoplasmic antibodies with more than 20 Juvenile Diabetes Foundation units were used. In 11 (78.6%) of 14 sera positive for 64 K antibodies, the reactivity of islet cell cytoplasmic antibodies was markedly blocked by pre-incubation with purified glutamic acid decarboxylase. In contrast, none of the 64 K antibody-negative sera were blocked. All of the patients showed similar clinical characteristics regardless of the inhibitory effect of glutamic acid decarboxylase on islet cell cytoplasmic antibodies, except for islet cell cytoplasmic antibody titer and glutamic acid decarboxylase antibody titer. The mean log 2 islet cell cytoplasmic antibody titer was 2.4 +/- 0.6 (mean +/- SD) JDF unit in the 'markedly blocked' group and 1.6 +/- 0.3 (mean +/- SD) in the 'never blocked' group. The islet cell cytoplasmic antibody titer was significantly higher (P < 0.05) in the former, and the mean glutamic acid decarboxylase antibody titer was 624 +/- 127.0 (mean +/- SE) units in the 'markedly blocked' group and 127 +/- 55.5 (mean +/- SE) in the 'never blocked' group. The glutamic acid decarboxylase antibody titer was also significantly higher (P < 0.05) in the former. We demonstrated here that some whole islet cell cytoplasmic antibodies are absorbed by purified glutamic acid decarboxylase, suggesting heterogeneity of islet cell cytoplasmic antibodies among the 64 K glutamic acid decarboxylase antibody positive group.

Absorption↗

Ganglion cells immunoreactive for catecholamine-synthesizing enzymes, neuropeptide Y and vasoactive intestinal polypeptide in the rat adrenal gland.

Immunohistochemistry has been used to demonstrate tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) immunoreactivities, and acetylcholinesterase (AChE) activity was demonstrated in rat adrenal glands. The TH, DBH, NPY and VIP immunoreactivities and AChE activity were observed in both the large ganglion cells and the small chromaffin cells whereas PNMT immunoreactivity was found only in chromaffin cells, and not in ganglion cells. Most intra-adrenal ganglion cells showed NPY immunoreactivity and a few were VIP immunoreactive. Numerous NPY-immunoreactive ganglion cells were also immunoreactive for TH and DBH; these cells were localized as single cells or groups of several cells in the adrenal cortex and medulla. Use of serial sections, or double and triple staining techniques, showed that all TH- and DBH-immunoreactive ganglion cells also showed NPY immunoreactivity, whereas some NPY-immunoreactive ganglion cells were TH and DBH immunonegative. NPY-immunoreactive ganglion cells showed no VIP immunoreactivity. AChE activity was seen in VIP-immunopositive and VIP-immunonegative ganglion cells. These results suggest that ganglion cells containing noradrenaline and NPY, or NPY only, or VIP and acetylcholine occur in the rat adrenal gland; they may project within the adrenal gland or to other target organs. TH, DBH, NPY, and VIP were colocalized in numerous immunoreactive nerve fibres, which were distributed in the superficial adrenal cortex, while TH-, DBH- and NPY-immunoreactive ganglion cells and nerve fibres were different from VIP-immunoreactive ganglion cells and nerve fibres in the medulla. This suggests that the immunoreactive nerve fibres in the superficial cortex may be mainly extrinsic in origin and may be different from those in the medulla.

Adrenal Glands↗