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Biomedical subjects

K Satoh

Publications and source records attributed to K Satoh.

At least 1,135 records · Page 63Linked to original sources
PubMed1983

Ultrastructural observations of the cholinergic neuron in the rat striatum as identified by acetylcholinesterase pharmacohistochemistry.

In order to examine the ultrastructural features of the cholinergic neuron in the striatum (caudatoputamen) of the rat, cytochemistry for acetylcholinesterase was conducted 2-12 h after intramuscular injection of the irreversible acetylcholinesterase inhibitor diisopropylphosphorofluoridate. Light microscopic examination of Epon sections reacted from acetylcholinesterase showed that only large-sized cells in the striatum (25-35 microns in the long axis) were stained intensely. In the case of longer survival periods (10-12 h), some lightly stained cells (medium-sized) were seen dispersed amongst the large acetylcholinesterase-rich cells. Electron microscopic observations were made on ultrathin sections of selected large acetylcholinesterase-rich neurons that were first studied by light microscopy. The nucleus of these cells has an eccentric position and possesses several indentations of the nuclear envelope. The cytoplasm contains abundant organelles, many exhibiting features unique to this cell type. Many stacks of granular endoplasmic reticulum, arranged in a parallel manner and forming typical Nissl bodies, were observed in the periphery of the perikarya, and many distinct golgi complexes were seen in the perinuclear zone. At all post-diisopropylphosphorofluoridate survival times, heavy deposits of acetylcholinesterase reaction product were found within the perikarya of this cell type, for the most part within the cisternae of the granular endoplasmic reticulum. At the longer post-diisopropylphosphorofluoridate survival times, reaction product within the cytoplasm was very dense and appeared to have reached a maximum level. At these times reaction product also appeared in the secondary and tertiary dendritic branches of the large-sized neurons. Of the other cell types in the striatum, two types of medium-sized cells displayed a light deposit of reaction product in their perikarya, but this was observed only at longer recovery times (8-12 h). The majority of cells in the striatum lacked reaction particles. Throughout the early post-diisopropylphosphorofluoridate period, the recovery of enzyme activity in the neuropil was moderate compared to that seen within cell bodies. These findings indicate that the large-sized neuron is the only striatal structure that shows rapid regeneration of acetylcholinesterase activity during the early recovery phase after diisopropylphosphorofluoridate administration. Previous studies have indicated that this type of neuron represents the cholinergic interneuron of the striatum. (ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗
PubMed1983

A comparison of the distribution of central cholinergic neurons as demonstrated by acetylcholinesterase pharmacohistochemistry and choline acetyltransferase immunohistochemistry.

The topographical distribution of cholinergic cell bodies has been studied in the rat brain and spinal cord by choline acetyltransferase (ChAT)-immunohistochemistry and acetylcholinesterase (AChE)-pharmacohistochemistry using diisopropylfluorophosphate (DFP). The ChAT-containing cells and the cells that stained intensely for AChE 4-8 hr after DFP were mapped in detail on an atlas of the forebrain (telencephalon, diencephalon) hindbrain (mesencephalon, rhombencephalon) and cervical cord (C2, C6). Striking similarities were observed between ChAT-positive cells and neuronal soma that stained intensely for AChE both in terms of cytoarchitectural characteristics, and with respect to the distribution of the labelled cells in many areas of the central nervous system (CNS). In the forebrain these areas include the caudatoputamen, nucleus accumbens, medial septum, nucleus of the diagonal band, magnocellular preoptic nucleus and nucleus basalis magnocellularis. In contrast, a marked discrepancy was observed in the hypothalamus and ventral thalamus where there were many neurons that stained intensely for AChE, but where there was an absence of ChAT-positive cells. No cholinergic perikarya were detected in the cerebral cortex, hippocampus, amygdala and dorsal diencephalon by either histochemical procedure. In the hindbrain, all the motoneurons constituting the well-established cranial nerve nuclei (III-VII, IX-XII) contained ChAT and exhibited intense staining for AChE. Further, a close correspondence was observed in the distribution of labeled neurons obtained by the two histochemical procedures in the midbrain and pontine tegmentum, including the laterodorsal tegmental nucleus, some areas in the caudal pontine and bulbar reticular formation, and the central gray of the closed medulla oblongata. On the other hand, AChE-intense cells were found in the nucleus raphe magnus, ventral part of gigantocellular reticular nucleus, and flocculus of the cerebellum, where ChAT-positive cells were rarely observed. According to both techniques, no positive cells were seen in the cerebellar nuclei, the pontine nuclei, or the nucleus reticularis tegmenti pontis. Large ventral horn motoneurons and, occasionally, cells in the intermediomedial zone of the cervical cord displayed ChAT-immunoreactivity and intense AChE staining. On the other hand, AChE-intense cells were detected in the dorsal portion of the lateral funiculus, but immunoreactive cells were not found in any portion of the spinal cord white matter.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗
PubMed1983

A New Mechanism for Adaptation to Changes in Light Intensity and Quality in the Red Alga Porphyra perforata: III. Fluorescence Transients in the Presence of 3-(3,4-Dichlorophenyl)-1,1-dimethylurea.

In the red alga Porphyra perforata, the level of chlorophyll fluorescence in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) decreased during illumination of the thallus. The results showed that: (a) this decay was related to the photooxidative activity of photosystem I; (b) Q, the primary electron acceptor of photosystem II, became oxidized during the decay of the fluorescence; (c) reagents which inhibit the back reaction of photosystem II inhibited the decay.From these results, it is suggested that, when conditions in the chloroplasts of this red alga become too oxidative, excess light energy can be converted to heat as a result of an accelerated back reaction of photosystem II. This may be one of the mechanisms by which this alga can cope with the high salt and high light conditions that can occur in its natural habitat.

Journal Article↗
PubMed1983

Effects of Salinity on Primary Processes of Photosynthesis in the Red Alga Porphyra perforata.

The effects of salinity on the primary processes of photosynthesis were studied in the red alga Porphyra perforata. The results show that there are at least three sites in the photosynthetic apparatus of this alga that were affected by increased salinity. The first site, photoactivation and dark-inactivation of electron flow on the reducing side of photosystem I, was completely inhibited at high salinity. The second site, electron flow on the oxidizing side (water side) of photosystem II, was inhibited as was the re-oxidation of Q in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. The third site affected by high salinity was the transfer of light energy probably from pigment system II to I. High salinity reduced the amount of light energy that reached the reaction centers of photosystem II.These effects are discussed in relation to the mechanisms available to this plant to avoid photoinhibition when it is exposed to stresses such as high light and high salinity which are conditions that are commonly found in the intertidal habitat.

Journal Article↗
PubMed1983

Molecular forms of glutathione S-transferase and UDP-glucuronyltransferase as hepatic preneoplastic marker enzymes.

Changes in molecular forms of glutathione S-transferase (GST) and UDP-glucuronyltransferase (UDP-GT) as hepatic detoxicating enzymes were investigated during chemical hepatocarcinogenesis in the rat. The activity and the protein amount (formula; see text) itself of the GST-A form, which has fetal characteristics and is separable from other forms by CM-Sephadex column chromatography and by immunologic techniques, was much increased in gamma-glutamyl transpeptidase (gamma-GTP)-positive foci or hyperplastic nodules (HNs) induced by diethylnitrosamine and 2-fluorenylacetamide or 3'-methyl-4-dimethylaminoazobenzene. The activity of enzyme 1 (late fetal form) of UDP-GT assayed with o-aminophenol (o-GT) also increased with increased number of the foci or HNs, while the activity of enzyme 2 (neonatal form) assayed with phenolphthalein (p-GT) changed but little. The foci and HNs were stained more strongly than the nonnodular areas immunohistochemically using the antibody against purified GST-A or o-GT. The two activities were also increased in well-differentiated hepatomas, but they were decreased in moderately and poorly differentiated hepatomas, and activating enzymes such as cytochrome P-450 were markedly decreased from HN. GST-A and o-GT differ from fetal enzymes such as those of carbohydrate metabolism in that they are inducible in the short-term by drugs, including carcinogens, and they show the highest activities in HNs, and so they may be considered as hepatic preneoplastic (PN) antigens.

Animals↗
PubMed1983

Urethral response to nerve stimulation measured by strain gauge force transducer.

This paper presents a study of urethral responses to efferent nerve stimulation in dogs. The pelvic, hypogastric and pudendal nerves were stimulated using a programmed instrument under three different in vivo conditions. The preparations consisted of: (A) bladder, urethra, and rectum; (B) urethra and rectum, and (C) urethra only. Stimulation of the pelvic nerve in preparation A resulted in elongation and constriction of the mid and proximal urethra with a resultant rise in pressure. However, this response was reduced in preparations B and C. Similar observations were made with hypogastric nerve stimulation. The results of pudendal nerve stimulation were significantly different, in that the pressure rise occurred in the mild and distal urethra and varied in elongation response.

Animals↗
PubMed1983

Metabolism of 14C-pregnenolone in the placenta throughout pregnancy in organ culture.

The present study was undertaken to assess the metabolism of radiolabeled pregnenolone in the placenta throughout pregnancy in organ culture. The product generated from pregnenolone was only progesterone regardless of the weeks of gestation. The amount of progesterone formed by the placenta was 5.60 +/- 0.15 x 10(-11) moles/mg protein/hour in the 1st trimester (n = 4), 6.47 +/- 0.09 x 10(-11) moles/mg protein/hour in the 2nd trimester (n = 3) and 7.72 +/- 0.25 x 10(-11) moles/mg protein/hour in the 3rd trimester (n = 6). The increase in the formation of progesterone as gestation advanced was statistically significant. The increase in the placental weight throughout pregnancy was in proportion to the rise in maternal plasma levels of progesterone. These data indicate that the manifold increase in progesterone in the maternal circulation as gestation advances mainly reflects the increase in the functional mass of the placenta rather than the increased rate of production of progesterone in the placenta.

Carbon Radioisotopes↗
PubMed1983

Improvement by trapidil of cardiac function of the dog heart-lung preparation depressed by pentobarbital.

The effect of trapidil on depressed cardiac function was investigated in 5 dog heart-lung preparations. Trapidil at a dose of 60 mg improved cardiac function which had been severely depressed by 70 +/- 32 (S.D.) mg of sodium pentobarbital. This dose of trapidil, however, produced no significant increase in heart rate. The results suggest that trapidil would be useful in the treatment of heart failure.

Animals↗
PubMed1983

Chemical analyses and antitumor activity of hydrosoluble substances from Mycobacterium bovis, strain BCG.

Hydrosoluble substances from BCG were prepared by cold water extraction and by hot phenol-water extraction. Chemical analyses revealed that both of them were derived from cytoplasm. The cold water extract (CWE) was effective in the treatment of C3H/He mice which had received an intraperitoneal inoculation of a syngeneic ascites hepatoma, MH134. The growth of a graft in footpad of mastocytoma P815 in CDF1 mice was retarded by intraperitoneal injections of CWE. A peptidoglycan from cell wall prepared by digestion with lysozyme exerted no antitumor activity in the same experimental condition as for the evaluation of antitumor effect of CWE. These results indicate that the antitumor activity of CWE was not due to the presence of a cell wall component.

Animals↗
PubMed1983

Sustained coronary constriction and its antagonism by calcium-blocking agents in monkeys and baboons.

Experiments were performed on five Japanese monkeys and one anubis baboon anesthetized initially with ketamine hydrochloride and subsequently with sodium pentobarbital, and maintained on artificial respiration. The left anterior descending coronary artery (LAD) was cannulated and its vascular bed was perfused with arterial blood. Perfusion pressure was kept constant at a value slightly higher than the mean systemic arterial pressure. Blood flow through the LAD was measured by an electromagnetic flow meter. All drugs were administered into the LAD. Single injections of acetylcholine produced a biphasic change in blood flow; an initial decrease (vasoconstriction) followed by an increase (vasodilation). Infusion of acetylcholine produced a sustained decrease in blood flow in all the animals used except one Japanese monkey in which oscillatory changes in blood flow were induced. With infusions of acetylcholine, however, left ventricular pressure (LVP), and maximum rate of rise of LVP (LV dP/dt max), heart rate, and systemic arterial pressure remained unchanged. Single injections of diltiazem and nifedipine, calcium-blocking agents, and nitroglycerin produced a dose-related increase in blood flow. Diltiazem and nifedipine exerted no effects on other cardiohemodynamic variables, whereas nitroglycerin produced a decrease in systemic arterial pressure and an increase in heart rate. When blood flow through the LAD was reduced to nearly half of the basal value by infusion of acetylcholine, diltiazem and nifedipine produced an increase in blood flow as much as in control, whereas nitroglycerin produced less of an increase than in control.

Acetylcholine↗
PubMed1983

Introduction of carbon substituents at C-2 position of purine nucleosides.

A series of new purine nucleosides which have carbon substituents at their C-2 position were synthesized by non-aqueous diazotization/deamination of 2-amino-6-chloro-9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)purine (1) with isoamyl nitrite in aromatic solvents and by palladium-catalyzed alkynylation of 2-iodo-adenosine (4) with terminal alkynes.

Alkylation↗
PubMed1983

Characterization of nucleolar antigens of normal rat liver, regenerating rat liver, and Novikoff ascites hepatoma cells following in vitro translation of polyadenylic acid-containing messenger RNA.

Nucleolar antigens of normal rat liver, regenerating liver, and Novikoff ascites hepatoma cells were transplanted in vitro from polyadenylic acid-containing messenger RNAs isolated from the respective tissues and immunoprecipitated with specific antinucleolar antibodies and Protein A. By two-dimensional gel electrophoresis of the translation products, five antigens were detected in normal rat liver. The antigens detected in 18-hr regenerating rat liver were the same as those of normal rat liver when immunoprecipitated with the anti-liver nucleolar antibodies. In the Novikoff tumor, 11 antigens were detected with anti-Novikoff nucleolar antibodies. Of these, two were not found in either normal or regenerating liver. Four major antigens were detectable in both Novikoff hepatoma and regenerating liver messenger RNA translation products with anti-Novikoff nucleolar antibodies. Two antigens were found in normal and regenerating liver that were not found in Novikoff hepatoma. In agreement with previous results, these immunoprecipitation analyses provide further evidence that some nucleolar antigens are present in Novikoff hepatoma that are not found in either normal or regenerating rat liver.

Animals↗
PubMed1982

Application of a galactosylceramidase microassay method to early prenatal diagnosis of Krabbe's disease.

An enzymatic microassay method was devised to determine galactosylceramidase activities of microsamples prepared from primary cultures of amniotic fluid cells. A piece of freeze-dried cell mass (0.5--1 microgram dry weight) prepared from a colony on the bottom plate of a culture flask, was weighed and incubated in 4.02 microliter of the assay mixture. A small amount of galactose hydrolyzed from galactosylceramide was amplified about 10 000-fold and determined by using an enzymatic amplification reaction, NAD cycling. Microsamples were also prepared from freeze-dried leukocytes and skin fibroblasts. The present method was applied to prenatal diagnosis using amniotic cells as a sample in a case of high-risk pregnancy for Krabbe's disease. The result was confirmed by analysis of fibroblasts and organs from the aborted fetus.

Amniotic Fluid↗