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Biomedical subjects

S Nakashima

Publications and source records attributed to S Nakashima.

At least 253 records · Page 14Linked to original sources
PubMed1986

Partial purification of phosphoinositide phospholipase C from human platelet cytosol; characterization of its three forms.

Three forms (I, IIa and IIb) of phospholipase C, hydrolyzing specifically inositol phospholipids, were resolved from human platelet cytosol and partially purified by DEAE-cellulose, phenyl-Sepharose, Ultrogel ACA-44 and hydroxylapatite column chromatographies. All three forms exhibited pH optimum at 6.5 - 7.0 in the presence of deoxycholate and their molecular weights were 67,000 (form I), 120,000 (IIa) and 70,000 (IIb). These enzymes hydrolyzed both phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate in Ca2+-dependent manner; their maximal activities for phosphatidylinositol hydrolysis were obtained at 10(-4) to 10(-3) M Ca2+, whereas phosphatidylinositol 4,5-bisphosphate was preferentially hydrolyzed at lower concentration of Ca2+.

Blood Platelets↗
PubMed1986

Inhibitory action of cyclic GMP on secretion, polyphosphoinositide hydrolysis and calcium mobilization in thrombin-stimulated human platelets.

The effect of cyclic GMP (cGMP) on human platelet activation was investigated, using its metabolically stable analogue, 8-bromo cGMP (8-bcGMP). Thrombin-induced serotonin secretion was inhibited by pretreatment with 8bcGMP in a dose-dependent manner. Production of inositol trisphosphate (IP3), a Ca2+ releaser was inhibited by 8bcGMP pretreatment of platelets. Preincubation of platelets with 8bcGMP was without effect on the basal level of cytosolic free Ca2+, measured by fluorescent indicator quin2, but suppressed its thrombin-induced enhancement independently of extracellular Ca2+. These results indicate that cGMP may be implicated in phospholipase C activation and Ca2+ mobilization (both influx through the plasma membrane and efflux from internal stores) in thrombin-activated human platelets.

Aminoquinolines↗
PubMed1986

Distribution of serotonin-containing cell bodies in the brainstem of the human fetus determined with immunohistochemistry using antiserotonin serum.

The distribution of serotonin (5HT) neurons was investigated in the brainstem of 8 human fetuses ranging in age from 15 to 27 weeks of gestation. We conducted the peroxidase-antiperoxidase (PAP) immunohistochemical technique using antiserotonin serum to detect the cell bodies of 5HT-containing neurons. Positively stained 5HT neurons were clearly demonstrated in the brainstem of all fetuses examined. They varied in shape, showing round to oval cell bodies with unipolar, bipolar, or multipolar processes. A large number of 5HT neurons were located in the midline raphe nuclei. In addition, numerous 5HT neurons were observed widely in the other tegmental areas. The nuclei containing 5HT neurons were listed according to the terminology by Olszewski and Baxter for human brainstem, and an atlas was given. The distribution of 5HT neurons in the raphe nuclei of human fetuses was essentially similar to those of many mammals already reported. However, the lateral extension of 5HT neurons to the other tegmental areas beyond the midline raphe nuclei was much greater in human fetuses compared to other mammals.

Brain Stem↗
PubMed1986

[Topography of the catecholamine neurons in the brain stem of the human fetus: an immunohistochemical study using antibodies to tyrosine hydroxylase].

Immunohistochemistry using antibodies to tyrosine hydroxylase (TH), a rate-limiting enzyme which catalyzes the initial step in the catecholamine synthesizing pathway, has been widely accepted as one of the methods for identification of catecholamine neurons in the nervous system. In the present study, we performed immunohistochemical examination to elucidate the distribution of catecholamine neurons in brain stem of human fetuses. The brain stems were obtained from 8 human fetuses (CRL: 120-275 mm, GA: 15-27 wks) 1-3 h after death following therapeutic or spontaneous abortion. They were immediately fixed with 4% paraformaldehyde in 0.1 M phosphate buffer, pH 7.4, dehydrated with graded ethanol, and embedded in paraffin. Serial 6 microns sections were cut from 7 different levels of the brain stem of each fetus. These sections were stained by peroxidase-antiperoxidase (PAP) technique using TH antisera. The TH antisera used were raised in rabbits by injecting purified TH from bovine adrenal medulla. The preparation and the specificity of TH antisera were described in detail elsewhere (Nakashima et al, 1983). Catecholamine neurons were clearly demonstrated in the brain stem of all fetuses. They could be recognized as catecholamine cell groups in the same manner as is done in experimental mammals. Among these cell groups, the catecholamine neurons showed distinct cytological features in shape and size. The distribution of catecholamine positive neurons in the brain stem was almost the same in the 8 human fetuses, and an atlas was given with anatomical explanation under the terminology of Olszewski and Baxter (1982) for the human brain stem. In the mesencephalon, a large number of catecholamine neurons lay in the nucleus substantiae nigrae, pars compacta, the nucleus paranigralis, the middle of the ventral tegmentum and the tractus tegmentalis centralis, and fewer catecholamine neurons were scattered in the other tegmental area. In addition, a group of small catecholamine neurons was located in the griseum centrale mesencephali near the aqueduct. In the pons, catecholamine neurons occurred mainly in the nucleus locus coeruleus and the nucleus subcoeruleus. A band of TH-positive neurons extended from the nucleus locus coeruleus to the dorsolateral tegmentum, and further to the roof of the fourth ventricle. Occasional catecholamine neurons were present in the area medial to the upper portion of the nucleus locus coeruleus. More caudally, a small number of catecholamine neurons were scattered in the area medial to the nervus facialis and adjacent to the nucleus facialis and the nucleus olivaris superior.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic Fibers↗
PubMed1986

Isoelectric focusing spectra of anti-bacterial alpha-amylase antibody unique for antigen-induced suppression.

The effect of intravenous (i.v.) administration of bacterial alpha-amylase (B alpha A) on the IgG antibody response to a subsequent challenge with B alpha A in incomplete Freund's adjuvant (IFA) varied with the difference in responsiveness of the parental strains. High-responder C3H/He (C3) mice given injections of either 200 or 4 micrograms of B alpha A, which alone were unable to trigger a detectable IgG antibody response, generated an enhanced response to an immunogenic challenge given 25 days after the last i.v. injection. The response of low-responder C57BL/6 (B6) mice previously exposed to B alpha A, following a different kinetic course depending on the exposing dose, reached a plateau lower than the levels of control responses (tentatively designated as high- and low-zone suppression). Prior exposure of (B6 X C3)F1 hybrids to 200 micrograms led to the enhanced response, whereas pretreatment with 4 micrograms rendered them partially tolerant to a subsequent challenge. These results suggest that the capacity to achieve low-zone suppression is inherited as a dominant trait. Isoelectric focusing (IEF) analysis revealed that these enhanced responses expanded antibody heterogeneity in a strictly restricted, strain-specific manner as observed during the normal antibody response, although the rate of expansion was accelerated. The specific antibodies produced by individual high-zone suppressed B6 mice were focused as a limited set of bands in a narrow pH range where the specific antibodies produced early in the normal response were focused. In contrast, the response of low-zone suppressed B6 and F1 hybrid mice was characterized by a unique process of heterogeneity expansion.

Animals↗
PubMed1986

Arachidonic acid mobilization among phospholipids in murine mastocytoma P-815 cells: role of ether-linked phospholipids.

The ethanolamine-containing glycerophospholipids, choline-containing glycerophospholipids, and phosphatidylinositol fractions are major sources of arachidonic acid in murine mastocytoma P-815 cloned cells. The choline-linked fraction contained high arachidonic acid contents in 1-O-alkyl-2-acyl- (18%) and 1,2-diacyl-sn-glycero-3-phosphocholine (11%), with smaller amounts in 1-O-alk-1'-enyl-2-acyl species, whereas the arachidonic acid content of the ethanolamine-linked fraction was high in 1-O-alk-1'-enyl-2-acyl (26%) and 1,2-diacyl species (15%) and low in 1-O-alkyl-2-acyl species. The uptake and transfer of [3H]arachidonic acid into the 1,2-diacyl and ether classes of choline-containing glycerophospholipids and ethanolamine-containing glycerophospholipids in mastocytoma cells were examined. There was very rapid incorporation of radioactive arachidonic acid into mastocytoma cells that leveled off after 30 min. By labeling cells with [3H]arachidonic acid for 7.5 min, the radioactivity was recovered in the choline-containing glycerophospholipids (43%), phosphatidylinositol (32%), and ethanolamine-containing glycerophospholipids (20%) with little in other phospholipids, neutral lipid, or free fatty acid fractions. Upon reincubation of the mastocytoma cells in the radiolabel-free medium, the [3H]arachidonate radioactivity was gradually lost from the choline-containing glycerophospholipids fraction and, concomitantly, increased in ethanolamine-containing glycerophospholipids. At the zero time of reincubation, most of the radioactivity was recovered in the 1,2-diacyl species of both choline-containing glycerophospholipids and ethanolamine-containing glycerophospholipids.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Fundamental and clinical studies on imipenem/cilastatin sodium in the field of pediatrics].

Fundamental and clinical studies on imipenem/cilastatin sodium (MK-0787/MK-0791) were performed in pediatric patients with infections. Results obtained were summarized below. The mean plasma half-life of MK-0787 was 0.84 hour with a dosage of 10 mg/kg and 0.90 hour with a dosage of 20 mg/kg. Mean plasma half-lives of MK-0791 were 0.40 hour and 0.71 hour for dosages of 10 mg/kg and 20 mg/kg, respectively. Urinary recovery of both MK-0787 and MK-0791 was high. The antibacterial activity of MK-0787 against clinically isolated organisms was determined. The MK-0787 was bactericidal against a broad spectrum of both Gram-positive and Gram-negative pathogens. The MK-0787/MK-0791 was administered to 32 pediatric patients with various infections. The overall clinical efficacy rate was 96.9%. Side effects observed were loose stools in one patient, diarrhea in another and slight elevations of platelet and direct bilirubin, and eosinophilia were observed in 3 patients, respectively.

Bacteria↗
PubMed1986

[Fundamental and clinical studies on cefixime in the pediatric field].

Fundamental and clinical studies on cefixime (CFIX), a new oral cephem antibiotic, were carried out in the pediatric field. The results were as follows: Serum concentrations and urinary recovery rates were determined after oral administration of CFIX at doses of 3 mg/kg and 6 mg/kg in 2 cases each (4 cases in total). The mean serum concentrations of CFIX were 0.52 and 0.58 micrograms/ml at 2 hours, 0.80 and 1.42 micrograms/ml at 4 hours, 0.73 and 1.36 micrograms/ml at 6 hours, 0.54 and 1.12 micrograms/ml at 8 hours, respectively. The mean peak serum concentration of CFIX was obtained at 4 hours after administration, with serum half-lives (T1/2) of 3.77 and 5.30 hours, respectively. The mean cumulative urinary recovery rates within 12 hours after administration of CFIX at doses of 3 mg/kg and 6 mg/kg were 8.4% and 6.8%, respectively. Antibacterial activities of CFIX against clinically isolated strains of S. pyogenes, S. pneumoniae. E. faecalis, S. aureus, E. coli, H. influenzae, H. parainfluenzae were compared with those of amoxicillin (AMPC), cefaclor (CCL), and cephalexin (CEX). It was observed that CFIX was a little less active than AMPC against S. pyogenes and S. pneumoniae, but CFIX was more active than CCL and CEX. CFIX was the most active against E. coli, H. influenzae and H. parainfluenzae. Twenty-one pediatric patients with bacterial infections (10, tonsillitis; 4, pharyngitis; and 7, urinary tract infections) were treated with CFIX at doses of 1.5-6.0 mg/kg in 2 or 3 times daily for 4-10 days. The efficacy rate was 95.2% clinically and 91.3% bacteriologically. No adverse reactions were observed. An abnormal laboratory finding (slight elevation of S-GOT and S-GPT) was observed in 1 case.

Acute Disease↗
PubMed1985

Inhibitory action of phorbol myristate acetate on histamine secretion and polyphosphoinositide turnover induced by compound 48/80 in mast cells.

Rat peritoneal mast cells which had been preincubated with phorbol myristate acetate (PMA, 10 - 100 ng/ml) for 5 min did not elicit the full histamine secretion induced by a potent secretagogue, compound 48/80. Furthermore, this PMA-treatment was found to inhibit the agonist-mediated hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) in [32P]labeled cells. However, it was also observed that the level of [32P]PIP2 was markedly reduced by 5 min-incubation with PMA. This suggests the enhanced hydrolysis of PIP2 by PMA which was reflected in a greater formation of inositol trisphosphate (IP3). These observations indicate that the formation of IP3 may not be profoundly related to secretory response in mast cells.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1985

A wasp venom mastoparan-induced polyphosphoinositide breakdown in rat peritoneal mast cells.

The phospholipid metabolism of rat peritoneal mast cells stimulated with mastoparan, a secretagogue purified from wasp venom, was investigated. Mastoparan at 20 micrograms/ml caused a rapid secretion of histamine. Mastoparan induced a transient decrease of phosphatidylinositol 4,5-biphosphate on 32P labeling and generation of a water-soluble degradation product, inositol trisphosphate on [3H]inositol labeling, suggesting the activation of phospholipase C upon stimulation.

Animals↗
PubMed1985

Arachidonic acid release in rat peritoneal mast cells stimulated with antigen, ionophore A23187, and compound 48/80.

Rat peritoneal mast cells respond to various types of secretagogues, such as antigen (receptor-mediated), A23187 (calcium mobilizing), and compound 48/80 (membrane perturbing), and release arachidonic acid from membrane phospholipids prelabeled with [3H]arachidonate. The rate of arachidonic acid liberation varied from one stimulant to the other. Ionophore A23187 (0.1 micrograms/ml) appeared to be most potent in releasing arachidonate among the three stimulants at which doses each secretagogue caused almost equivalent histamine secretion. However, upon stimulation with these three secretagogues, the radioactivity of phosphatidylcholine (PC) was markedly reduced with a concomitant increase of arachidonate radioactivity. Hydrolysis of PC by phospholipase A2 is likely to be the major route of arachidonic acid liberation in either IgE-mediated or non-IgE activation in mast cells.

Animals↗
PubMed1985

Catecholamine neurons with Alzheimer's neurofibrillary changes and alteration of tyrosine hydroxylase. Immunohistochemical investigation of tyrosine hydroxylase.

Immunohistochemistry with antisera against tyrosine hydroxylase was performed on neurons with Alzheimer's neurofibrillary changes in the substantia nigra and locus ceruleus. These specimens were obtained from brains with Alzheimer's disease, Pick's disease, progressive supranuclear palsy, Alzheimer's type parkinsonism, parkinsonism-dementia complex on Guam, and normal aging. Under these neurologic conditions the affected catecholamine neurons with Alzheimer's neurofibrillary changes were stained positively with antisera against tyrosine hydroxylase. The results suggested that in these neurons, Alzheimer's neurofibrillary changes seemed to develop independently before the reduction of tyrosine hydroxylase protein synthesis.

Adult↗
PubMed1985

Evidence that arachidonic acid is deficient in phosphatidylinositol of Drosophila heads.

We have found that arachidonic (20 : 4) acid is indetectable in phosphatidylinositol and diacyglycerol extracted from Drosophila heads. After careful examinations of the lipid extraction processes and fatty acid detection system (gas-liquid chromatography), we excluded the possibility of the oxidation of polyunsaturated fatty acids or of having overlooked a trace amount of the fatty acid. The precursors of arachidonic, dihomo gamma-linolenic (20 : 3), and gamma-linolenic (18 : 3) acid, were also indetectable in these lipids. On the basis of these results, it appears that the arachidonic acid cascade is essentially absent in Drosophila head, including the brain and compound eyes. Since arachidonic acid is considered to be a key molecule in phosphatidylinositol turnover in the brain, it is of interest that Drosophila brain and eyes do not require arachidonic acid for their functions.

Animals↗