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Biomedical subjects

N Saito

Publications and source records attributed to N Saito.

At least 19 recordsLinked to original sources
PubMed1992

Expression of protein kinase C subspecies in rat retina.

An extract of rat retina was subjected to Mono Q followed by chromatography on hydroxyapatite, and the protein kinase C (PKC) subspecies were identified by immunoblot and biochemical analysis. It was found that, although the relative activities assayed with myelin basic protein as a common phosphate acceptor vary greatly with one another, the alpha-, beta I-, beta II-, gamma-, delta-, epsilon-, zeta-, and another structurally unknown PKC subspecies are expressed in this tissue. Thus, the retina is a unique tissue which expresses most of the PKC subspecies so far identified in mammals.

Animals↗
PubMed1992

The loss of beta II-protein kinase C in the striatum from patients with Huntington's disease.

We have examined the levels of protein kinase C (PKC) in autopsied brains of patients with Huntington's disease (HD), using [3H]4-beta-phorbol-12,13-dibutyrate ([3H] PDBu) and antisera against the PKC subspecies. In the caudate nucleus and putamen from patients with HD, the specific binding for [3H]PDBu was significantly decreased by 74 and 68%, respectively, as compared to findings in controls. The beta II-PKC immunoreactivities were significantly reduced by 65%, whereas the alpha-PKC immunoreactivities increased by 146%, in the putamen. There were no differences in the beta I- or gamma-PKC immunoreactivities in the putamen between HD and controls. These results suggest the differential localization of four PKC subspecies in human striatum and the involvement of four subspecies in different aspects of HD pathophysiology.

Brain↗
PubMed1992

Expression of Fos-like immunoreactivity by yohimbine and clonidine in the rat brain.

To elucidate the role of alpha 2-adrenoceptors in transcriptional control in the rat brain, we localized the Fos-like immunoreactivity (Fos-LI) induced by alpha 2-adrenoceptor agonists and by an antagonist. Injections of yohimbine (5 mg/kg, i.p.) into rats led to the induction of Fos-LI in areas with a dense alpha 2-adrenoceptor binding such as the locus coeruleus, the bed nucleus of stria terminalis, the central nucleus of amygdaloid complex, the paraventricular nucleus, the nucleus tractus solitarius, and ventrolateral medulla oblongata. Clonidine (500 micrograms/kg, i.p.) suppressed the Fos expression by yohimbine in these nuclei, and clonidine (100 micrograms/kg, i.p.) or guanabenz (4 mg/kg, i.p.) induced Fos-LI in oxytocin neurons in the paraventricular and supraoptic nuclei in the hypothalamus. Thus, the alpha 2-adrenoceptor is involved in transcriptional control via Fos expression in neurons related to autonomic and other functions.

Animals↗
PubMed1992

Expression of myeloid cell phenotypes by a novel adult T-cell leukemia/lymphoma cell line.

BACKGROUND: Human T-cell leukemia virus type 1 (HTLV-1) can infect a number of cells of different lineages in vitro, yet the immunophenotypes of most adult T-cell leukemia/lymphomas (ATLs) are restricted to CD4+. The apparent discrepancy between these findings is still largely unknown. PURPOSE: We report on a unique case of ATL in which the leukemia cells were positive for both T-cell and myeloid cell antigens. To characterize these cells, we isolated cell lines from this patient with ATL. METHODS: The fresh leukemia cells were cultured without the addition of interleukin-2. Cell cloning was carried out by limiting dilution. RESULTS: A cell line (MU) and its clonal sublines were established. MU cells showed the same chromosomal abnormalities and T-cell receptor beta-chain gene rearrangement pattern as those of fresh leukemia cells. MU cells were exclusively positive for a myeloid cell marker (CD13) but not for T-cell markers, despite the presence of T-cell receptor gene rearrangement. CONCLUSION: The established ATL cell line showed both T-cell and myeloid cell characteristics, which seems to be the first evidence for the close association of ATL cells with both lymphoid and myeloid features. The cell line may provide a new insight for the targets of HTLV-1 infection and transformation in vivo.

Adult↗
PubMed1992

Application of immunocryoultramicrotomy to free cells: ultrastructural localization of myeloperoxidase in neutrophils of human peripheral blood.

Immunocryoultramicrotomy is generally considered the most suitable method for observing the immunostainings by monoclonal antibodies to intracellular antigens by electron microscopy. However, this procedure with the free cells such as peripheral blood cells or cultured cells is not widely used because of the difficulty in preparing ultrathin frozen sections. We report here a new technique for making ultrathin frozen sections of peripheral blood cells by positioning the cell in a semigelatinized medium for ultrasectioning. Monoclonal antibody against myeloperoxidase (MPO) was reacted with the ultrathin sections made with this new technique to observe the ultrastructural localization of intracellular MPO. MPO was observed in the primary granules of the neutrophils.

Antibodies, Monoclonal↗
PubMed1992

In vitro release of glutamate and aspartate from zebra finch song control nuclei.

The release of glutamate and aspartate from a song control nucleus, the robust nucleus of the archistriatum (RA) of the zebra finch was examined in slice preparations. The RA received inputs from two other song control nuclei, the high vocal center (HVc) and the lateral magnocellular nucleus of the anterior neostriatum (1MAN). The fibers that innervated the RA from either the HVc or the 1MAN caused calcium-dependent release of glutamate and aspartate after electrical stimulation. It is likely that synapses of the RA from the HVc and the 1MAN utilize glutamate or aspartate as a neurotransmitter.

Animals↗
PubMed1992

Steroid complications in patients with ulcerative colitis.

Physicians treating patients with ulcerative colitis are confronted with the difficult task of deciding whether medical or surgical treatment is best for their patients. There are no definitive criteria to indicate when medical therapy should be exchanged for definitive surgery. Even in patients who respond well to glucocorticoid treatment, the side effects of these drugs may necessitate surgery. We reviewed the steroid complications of our operative cases retrospectively. Although ulcerative colitis was usually in remission, severe steroid complications were no longer tolerable and definitive surgery was required. We also reviewed the literature regarding the adverse effects of steroid. Because of advances in sphincter-preserving surgery, re-evaluation of the treatment of ulcerative colitis is necessary. Although conservative treatment remains the first choice, tolerance of irreversible side effects (especially in children) no longer seems to be justified. In such patients, early definitive surgery may offer more than it appears to sacrifice.

Adult↗
PubMed1992

Acylated pelargonidin glycosides in the red-purple flowers of Pharbitis nil.

Four acylated pelargonidin glycosides and pelargonidin 3-sophoroside-5-glucoside were isolated from 23 red-purple cultivars of Pharbitis nil. The acylated anthocyanins were all based on pelargonidin 3-sophoroside-5-glucoside and were identified as the 3-O-[2-O-(beta-D-glucopyranosyl)-6-O-(trans-caffeyl)-beta-D- glucopyranoside]-5-O-(beta-D-glucopyranoside), the 3-O-[2-O-(6-O-(trans-3-O-(beta-D-glucopyranosyl)caffeyl)-beta- D-glucopyranosyl)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside), the 3-O-[2-O-(6-O-(trans-3-O-(beta-D-glucopyranosyl)caffeyl)-beta- D-glucopyranosyl)-6-O-(trans-caffeyl)-beta-D-glucopyranoside]-5-O-(beta- D-glucopyranoside); and the 3-O-[2-O-(6-O-(trans-3-O-(beta-D-glucopyranosyl)caffeyl)-beta-D- glucopyranosyl)-6-O-(trans-4-O-(6-O-(trans-3-O-(beta-D- glucopyranosyl)caffeyl)- beta-D-glucopyranosyl)caffeyl)-beta-D-glucopyranoside]-5-O-(beta-D- glucopyranoside). By the analysis of these anthocyanin constituents variously in 23 cultivars, it was found that the red flower colour gradually changed into more bluish colour with increasing numbers of caffeic acid residues in the acylated pelargonidin glycosides. The stabilities of these anthocyanins increased in the order of increasing caffeyl substitution.

Anthocyanins↗
PubMed1992

Localization of subspecies of protein kinase C in the mammalian central nervous system.

Activation of protein kinase C (PKC) is regulated by dual second messengers; diacylglycerol (DG) produced by receptor mediated hydrolysis of phosphatidylinositol and Ca2+ which is released by inositol 1,4,5-triphosphate (IP3) from intracellular stores in the endoplasmic reticulum. In the mammalian central nervous system, available evidence suggests that PKC plays a prominent role in the processing of neuronal signals and in the short-term or long-term modulation of synaptic transmission. This enzyme is a member of a family consisting of at least eight subspecies, alpha, beta I, beta II, gamma, delta, epsilon, zeta and eta. The homologous structure of each subspecies makes difficult resolution of the enzymological properties of the enzyme. The distinct functional roles of PKC subspecies in mammalian tissues have been elucidated by defining the localization of each subspecies. We identified alpha-, beta I-, beta II- and gamma-PKC subspecies in the rat brain by in situ hybridization and by light and electron microscopic immunohistochemistry, using antibodies specific for each subspecies. Most immunoreactions of the alpha, beta I, beta II and gamma subspecies were evident in neurons and there were few, if any, in glial cells. In this article, we summarize known cellular and subcellular localizations of PKC subspecies in mammalian CNS and some aspects of current studies in neuronal functions regulated by this enzyme are discussed.

Amino Acid Sequence↗
PubMed1992

Global cerebral ischemia associated with cardiac arrest in the rat: I. Dynamics of early neuronal changes.

Light microscopic neuronal changes were studied in rats subjected to 10 min of global ischemia produced by compression of the major cardiac vessels. Observations of cresyl violet-stained sections revealed early changes involving predominantly GABAergic neurons in various locations. In rats killed 15 min after recirculation, the changes were characterized by the appearance of a clear peripheral zone with condensation of the remaining neuronal cytoplasm. After 1 h, these zones appeared to be compartmentalized into individual pearl-like vacuoles, especially prominent in the nucleus reticularis thalami. After 3 h, the cytoplasmic vacuoles disappeared and the neuronal changes, particularly in the cerebral cortex, striatum, hippocampus, and pars reticulata of the substantia nigra, consisted mainly of hyperchromasia or loss of Nissl substance. After 2 days, the cerebral cortex and thalamus contained occasional neurons with conspicuously large nucleoli. After 7 days, the hippocampus revealed an approximately 50% loss of CA1 pyramidal neurons, associated with intense microglial reactivity in the stratum radiatum, whereas the neuronal destruction was more complete in the nucleus reticularis thalami. Our observations suggest a possibility that early changes in GABAergic neurons may provide a period of neuronal disinhibition and thus contribute to an excitatory ischemic damage in regions connected by GABAergic circuitry.

Animals↗
PubMed1992

Alterations in uterine contractility during the oviposition cycle in domestic hens.

1. The potencies of several neurohypophysial hormones were examined at different times during the oviposition cycle in an in vitro fowl oxytocic assay. 2. Uterine tissues were removed 2 h before (-2h-OP), immediately after (0h-OP) and 5 h after (+5h-OP) spontaneous oviposition. In addition, uterine tissue was removed immediately after oviposition was induced, by administering prostaglandin E2 2 h before an expected oviposition (Induced-OP). 3. The rank order of oxytocic potencies for the peptides was arginine vasotocin = vasopressin greater than oxytocin greater than mesotocin. The sensitivity of the uterus to the hormones was 0h-OP = Induced-OP greater than -2h-OP = +5-OP. 4. These results suggest that uterine sensitivity to neurohypophysial hormones changes during the oviposition cycle in domestic fowls.

Animals↗
PubMed1992

Distinct cellular expression of calcineurin A alpha and A beta in rat brain.

Specific polyclonal antibodies that distinguish the two distinct isoforms of the catalytic subunit of calmodulin-dependent protein phosphatase, calcineurin A alpha and A beta, were prepared, and the distribution of calcineurin A alpha and A beta in rat brain was studied using immunochemical and immunocytochemical techniques. Immunochemical measurement revealed that the regional distributions of the two isoforms differed and that A alpha was more abundant than A beta in the rat brain. The subcellular distribution patterns of both isoforms were similar. Both isoforms were highly enriched in cytosolic fractions, including the synaptosomal cytosol. Immunocytochemical analysis revealed that both A alpha and A beta immunoreactivities differed in regional and cellular localizations. These different patterns of expression suggest that the two isoforms of calcineurin A may each have specific functions in modulating neuronal activity in particular cell types.

Animals↗
PubMed1992

Evidence for distinct neuronal localization of gamma and delta subunits of Ca2+/calmodulin-dependent protein kinase II in the rat brain.

Localization of the gamma and delta types of mRNAs for Ca2+/calmodulin-dependent protein kinase II (CaM-kinase II) was determined in the rat brain, making use of in situ hybridization histochemistry. The gamma and delta mRNAs as well as the alpha and beta mRNAs for CaM-kinase II were heterogeneously and distinctly distributed. In the Purkinje cell layer of the cerebellum, alpha, beta, and gamma mRNAs but not delta mRNA were present, whereas beta, gamma, and delta mRNAs were present in the locus coeruleus. These findings provide evidence that CaM-kinase II exists in a variety of forms in different cells composed of a variable number and type of subunits.

Animals↗
PubMed1992

Effects of removal of chicks from hens on concentrations of prolactin, luteinizing hormone and oestradiol in plasma of brooding Gifujidori hens.

Gifujidori hens were allowed to repeat a breeding cycle in one season. In the first breeding cycle the duration of the brooding (raising chicks) stage was limited to 3 weeks, whereas in the second breeding cycle it was limited to 1 week by removing all chicks from mother hens. In the first breeding cycle, plasma prolactin (PRL) was high during the incubation period, but rapidly decreased on the day of hatching and reached minimum values about 1 week after hatching. In contrast, plasma luteinizing hormone (LH) concentrations were low during the incubation period, but after hatching they gradually increased and reached peak values immediately after removal of chicks. Concentrations of oestradiol in plasma were low in the incubation and brooding stages but increased significantly immediately after removal of chicks. In the second breeding cycle, changes in PRL and LH concentrations were similar to those observed in the first breeding cycle except that even greater increases in plasma LH and oestradiol concentrations were observed one week after hatching when the chicks were removed. These results suggest that coexistence of newly hatched chicks may suppress LH secretion from the pituitary of the hen in the natural breeding cycle.

Animals↗