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Biomedical subjects

Y Tamai

Publications and source records attributed to Y Tamai.

At least 163 records · Page 9Linked to original sources
PubMed1990

[The effect of ginger on serotonin induced hypothermia and diarrhea].

One of the important medicinal properties of ginger is known to remove chills caused by common cold and to warm body. In the present study, acetone extract of ginger at 100 mg/kg p.o. significantly inhibited serotonin (5-HT) induced hypothermia. Therefore, the active constituents of ginger were further examined. The acetone extract was functioned into 4 fractions by column chromatography. Fractions 1 and 2 showed significant activity. Fraction 2 was further purified and [6]-shogaol which was obtained from fraction 2-2, at 10 mg/kg p.o. was shown to inhibit 5-HT induced hypothermia. Anticathartic activity is known to be one of the medicinal effects of ginger. In the present study, acetone extract of ginger at 75 mg/kg p.o., significantly inhibited 5-HT induced diarrhea. In order to clarify the active constituents, the acetone extract was fractionated into 4 fractions by silica gel chromatography. Fractions 2 and 3, which was especially effective, were further purified and [6]-shogoal, [6]-dehydrogingerdione, [8]- and [10]-gingerol were found to have an anticathartic action. [6]-Shogaol was more potent than [6]-dehydrogingerdione, [8]- and [10]-gingerol.

Acetone↗
PubMed1990

Stabilization of tumor antigens by chemical modification with diethyl pyrocarbonate.

C3H mice were immunized with MH134 tumors modified with two different chemicals, DEPC and TNBS, and the tumor-neutralizing activities of the spleen cells were examined after separating the cells by a Nylon-wool column, plastic dish, or treatment with specific antibodies (anti-mouse IgG and anti-mouse theta sera). The effector cells induced in mice by immunization with TNBS-treated tumors were T cells. In contrast, in the case of tumors modified with DEPC, macrophages were the major effector cells. The effects of chemical modification on the solubilization of cell surface proteins was also examined. DEPC inhibited solubilization of specific proteins from tumor cell surfaces, while TNBS did not have such an effect on the solubilization of proteins. These results indicate that the antitumor response in mice primed with DEPC-modified tumor is different from the case of TNBS-modified tumors, and that the immunological significance of chemical modification with DEPC is supposedly due to the stabilization of antigenic proteins on the tumor cell surface.

Animals↗
PubMed1990

Identification and characterization of a thermolabile antigen (TLAa, enolase) in Saccharomyces cerevisiae.

Five kinds of proteins of Saccharomyces cerevisiae were recently purified to a homogeneous state and identified as yeast cell surface antigens (TLAa, TLAb, TLAc, TLAd, and TLAe), but their physiological functions remained uncertain. In this paper, TLAa was identified as a yeast enolase (EC 4.2.1.11) from the following evidence: (1) molecular weights and amino acid compositions of both proteins were similar, (2) the N-terminal 22 amino acid sequences of both proteins were the same (3), TLAa had enolase activity, and (4) the authentic yeast enolase gave a positive reaction with anti-TLAa serum in the Ouchterlony immunodiffusion test and the immunoblotting test. Two isoproteins of TLAa (enolase) were separated by non-denatured polyacrylamide gel electrophoresis and detected by immunoblotting with anti-TLAa serum. The contents of the two isoproteins varied depending on the following culture conditions: glucose starvation, growth in the presence of non-fermentable carbon sources, and growth in media containing sodium chloride and 2-deoxyglucose. The contents did not vary, however, with heat shock treatment or with growth in media containing sodium azide, tunicamycin, or sorbitol. These results showed that TLAa was a cytoplasmic antigen, and that its synthesis was regulated by some environmental stresses.

Amino Acid Sequence↗
PubMed1989

Subcortical connections of frontal 'oculomotor' areas in the cat.

The subcortical connections of the frontal 'oculomotor' areas in the medial wall of the hemisphere under the cruciate sulcus (CRUo), the medial (PREo-m) and the lateral banks (PREo-l) of the presylvian sulcus of cats were investigated using WGA-HRP tracing combined with electrophysiological techniques. Two main modes were identified; one was the common connections to the same targets in the cortico-thalamo-cortical, cerebro-cerebellar and cortico-tectal pathways, and the other was the individual connections to unique portions of the saccade-generating centers in the brainstem. The common reciprocal connections were found in the ventral anterior-ventral lateral complex, principal ventromedial nucleus, rostral intralaminar nuclei, centromedian-parafascicular complex, lateral posterior nucleus, and suprageniculate nucleus. The common efferent projections were in the subthalamic nucleus, lateral habenular nucleus, pretectal nucleus, posterior commisure nucleus, nucleus of Darkschewitsch, pontine nucleus, nucleus reticularis tegmenti pontis, medial accessory inferior olive, and the superior colliculus. The CRUo projected into the ipsilateral field of Forel and paramedial pontine reticular formation (PPRF), the PREo-l projected into the contralateral dorsomedial medullary reticular formation, and the PREo-m projected into the ipsilateral medullary reticular formation and there was only a small degree of projection into the central portion between the abducens nerve rootlets.

Animals↗
PubMed1989

Characterization of human interleukin-3 receptors on a multi-factor-dependent cell line.

Recombinant human interleukin-3 (hIL-3) was radioiodinated by Bolton-Hunter method with maintenance of biological activity. Using 125I-hIL-3, hIL-3 receptors were characterized on a multi-factor-dependent cell line TF-1. Equilibrium binding studies revealed the existence of a single class of binding sites (667 +/- 306 sites/cell) with a Kd of 173 +/- 25 pM. Affinity labeling of TF-1 cells with 125I-IL-3 yielded two bands of 150 kDa and 85 kDa, implying molecular weights of 135 kDa and 70 kDa for the hIL-3 receptors.

Cell Line↗
PubMed1989

Adult pigment type (Peiffer) of sudanophilic leukodystrophy. Pathological and morphometrical studies on two autopsy cases of siblings.

Two autopsy cases of siblings with the adult pigment (Peiffer) type of sudanophilic leukodystrophy (SLD), which demonstrated the full-blown stage (case 1) and early stage (case 2) of demyelination, were examined. Numerous brown pigments deposited in demyelinated cerebral areas were characterized histochemically and ultrastructurally as lipofuscin and ceroid. Under the electron microscope formation of blebs due to myelin splitting associated with deposition of multilamellar myeloid bodies within them was a prominent feature in the demyelinated cerebral areas of case 2 as compared with case 1. However, various features of myelin degradation such as thinning, partial or complete circumferential myelin loss, and deposition of electron-dense material on the interperiodic lines were found in both cases. Blebs occurred in all layers of myelin, and axons were compressed by these blebs or the hydropically swollen inner lips of oligodendroglias. Oligodendroglias were relatively well preserved in the demyelinated and nondemyelinated areas in case 2, although the cytoplasm was hydropic. Many spheroids were present in demyelinated areas and were irregularly distributed in both cases. The peripheral nerves in case 1 presented essentially the same changes as those in the brain, although those in case 2 were not affected. Morphometrically, the results showed that hypomyelination was not the mechanism for this pigment type of SLD. One possible cause may be an accelerated ageing of the metabolic process of myelin turnover.

Astrocytes↗
PubMed1989

Subcortical connections of an 'oculomotor' region in the ventral bank of the anterior ectosylvian sulcus in the cat.

Subcortical connections of an 'oculomotor' region in the ventral bank of the anterior ectosylvian sulcus (AESo), where eye movements were evoked by intracortical microstimulation, were studied in cats using a wheatgerm agglutinin horseradish peroxidase (WGA-HRP) tracing method. Following injection of WGA-HRP into the AESo, both anterogradely-labeled terminals and retrogradely-labeled cells were found with the highest concentration in the suprageniculate nucleus and the medial zone of the lateroposterior nucleus of the thalamus. In the brainstem, anterogradely-labeled terminals were found in the superior colliculus, the pontine reticular formation, the pontine tegmental reticular formation and the pontine nuclei.

Animals↗
PubMed1989

Eye movements following cortical stimulation in the ventral bank of the anterior ectosylvian sulcus of the cat.

Eye movements were induced by stimulating the ventral bank of the anterior ectosylvian sulcus (AES) of chloralose-anesthetized cats. Intracortical microstimulation of this cortex evoked centering movements of both eyes. The latency of eye movement was 45 ms (range 40-60 ms) and the intensity of stimulation was 33 microA (range 20-45 microA). The evoked eye movements persisted after ablation of the classical frontal eye field of both sides. These results suggest that the ventral bank of the AES is involved in the control of eye movements.

Animals↗
PubMed1989

Subcellular distribution of the transmissible agent in Creutzfeldt-Jakob disease mouse brain.

To determine the intracellular localization of the Creutzfeldt-Jakob disease (CJD) agent in mouse brain, cerebrum tissue of the mouse brain affected with the Fukuoka-1 strain was separated into six subcellular fractions (microsome, nerve ending, myelin, mitochondria, nucleus, and soluble fractions) by differential sucrose density gradient, and then the CJD infectivity of these fractions was examined. Serially diluted samples of each subfraction were inoculated intracerebrally into groups of BALB/c mice, and the infectivity was determined as to end point titration value, incubation period, and number of affected mice. On the basis of the protein content, the highest CJD infectivity was observed in the microsomal fraction. The nerve ending (synaptic plasma membrane) and myelin fractions were also infective. The mitochondria and nucleus fractions showed the lower infectivity. The infectivity of the soluble fraction was the lowest among the six subcellular fractions. From the findings obtained in this study two possibilities as to the intracellular localization of CJD agent were suggested: 1) the transmissible agent of CJD is closely associated with surface membranes of neuronal and/or glial cells, including their processes; 2) the CJD agent is diffusely present intracellularly, including in the surface membranes, but for manifestation of infectivity the agent needs membrane components as prerequisite factors.

Animals↗
PubMed1989

[Malignant tumors of the ethmoid sinuses--treatment and prognosis].

From 1981 to 1987, 15 cases of malignant tumors of the ethmoid sinuses were treated by radiotherapy, either with or without chemotherapy. Pathologically, these cases consisted of 7 squamous cells ca., 2 transitional cells ca., 3 anaplastic ca., 1 adenoid cystic ca., 1 malignant teratoma, and 1 rhabdomyosarcoma. The three-year survival in all cases 37%. Of eight patients determined to be in stages I and II, 4 patients had a localized relapse locally within 10 months after treatment and a distant metastases developed at a later time in 4 patients, whereas in 7 patients in stage III and IV, a distant metastases developed in 5 patients immediately after radiotherapy.

Adult↗
PubMed1988

A novel ganglioside in dogfish brain. Occurrence of a trisialoganglioside with a sialic acid linked to N-acetylgalactosamine.

A novel trisialoganglioside has been isolated from dogfish (Squalus acanthias) brain. From the results of gas chromatography-mass spectrometric analysis of methylated sugars, enzymatic hydrolysis, fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance analysis, its structure was concluded to be (formula; see text) This is the first report of the occurrence of a ganglioside with 3 sialic acid residues separately linked to its gangliotetraosyl backbone.

Acetylgalactosamine↗
PubMed1988

Thermotropic behavior and electronmicroscopic structures of mixtures of gangliosides and dipalmitoylphosphatidylcholine.

The calorimetric properties and morphological structures of dispersed mixtures of 1, 2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and highly purified human brain gangliosides, GM2, GM1, GD1a, GD1b, and GT1b, were studied using a high-sensitivity differential scanning calorimeter and an electron-microscope, as a function of the ganglioside molar fraction. No thermal phase transitions of pure gangliosides in aqueous dispersions could be detected. In the mixtures of DPPC and gangliosides, the gel to liquid crystalline phase transition occurred at a higher temperature than in pure DPPC dispersions and progressed over a wide temperature range. As increasing amounts of the pure ganglioside species were added to DPPC, the temperature for the main transition gradually increased. The phase transition progressed differently among different gangliosides/DPPC mixtures. The enthalpy values were found to decrease linearly as the number of sialic acid residues increased. Electron-microscopically the ganglioside/DPPC mixtures formed multilamellar structures at lower concentrations of the gangliosides, and the structures changed to cylindrical and spherical micelles as the ganglioside concentration was increased. The polysialoganglioside/DPPC mixtures showed the micellar form even at lower ganglioside concentrations, contrary to the case of the monosialoganglioside/DPPC mixtures. The morphological changes of gangliosides/DPPC mixtures corresponded with changes in the calorimetric properties. These results show that individual gangliosides have different physicochemical effects on model membranes, possibly because of the interaction of their negatively charged head groups.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1988

Purification and some properties of membrane-bound phospholipase B from Torulaspora delbrueckii.

Membrane-bound phospholipase B was purified to a homogeneous state from Torulaspora delbrueckii cell homogenate. Cell homogenate was extracted with Triton X-100, and the enzyme was precipitated with acetone. The acetone powder was washed repeatedly with Tris-HCl buffer (pH 8.0) until no phospholipae B activity was detected in the soluble fraction. The enzyme was extracted with Triton X-100 from the final residue and purified about 1,390-fold by sequential chromatofocusing, Sepharose 6B, and DEAE-Sephadex A-50 column chromatography. The final preparation showed a single broad protein band on SDS-polyacrylamide gel electrophoresis when stained with silver stain reagent and PAS-reagent. The molecular weight of phospholipase B was about 390,000 and 140,000-190,000 as estimated by gel filtration on Sepharose 6B and SDS-polyacrylamide gel electrophoresis, respectively, suggesting that phospholipase B is an oligomeric protein. The isoelectric point was at pH 4.5. Phospholipase B has two pH optima, one acidic (pH 2.5-3.0) and the other alkaline (pH 7.2-8.0). At acidic pH the phospholipase B activity was greatly increased in the presence of divalent metal ions, although metal ions are not a factor for enzyme activity. On the other hand, at alkaline pH the enzyme required Ca2+ or Mn2+ for activity. The pH- and thermal-stabilities at both pHs were similar. The phospholipase B hydrolyzed all diacylphospholipids tested at acidic pH, but hydrolyzed only phosphatidylcholine at alkaline pH. The hydrolysis rates of lysophospholipids were much higher (about 10-fold) than those of diacylphospholipids at both pHs.

Cations, Divalent↗
PubMed1988

Monocular eye movement in the cat: its corticotectal pathway.

The corticotectal pathway from the fundus of the cat's coronal sulcus (CORo) from which monocular movements of contralateral eye were evoked was studied using electrophysiological and anatomical techniques. Neurons in the CORo were activated antidromically by electrical stimulation of the deep layer of the superior colliculus (SC). Labeled cells were found in the CORo following horseradish peroxidase injection in the SC.

Animals↗
PubMed1988

Effect of the dietary alpha-linolenate/linoleate balance on lipid compositions and learning ability of rats. II. Discrimination process, extinction process, and glycolipid compositions.

Donryu strain rats through two generations were fed semi-purified diets supplemented with safflower seed oil (rich in linoleic acid) or with perilla seed oil (rich in alpha-linolenic acid), or a conventional laboratory chow (normal control diet). Brightness-discrimination learning ability was determined to be the highest in the perilla oil-fed group, followed by the normal group, and then by the safflower group, extending our earlier observation in a different strain of rat that alpha-linolenic acid is a factor in maintaining high learning ability (Yamamoto, N., M. Saitoh, A. Moriuchi, M. Nomura, and H. Okuyama. 1987. J. Lipid Res. 28: 144-151). After the brightness-discrimination learning test was administered, extinction of learning was measured. The time required for extinction was significantly longer in the safflower group than in either the perilla group or the normal diet group. Thus, the dietary alpha-linolenate/linoleate balance affected both the learning and the extinction of learning. The glycolipids of the cerebrum, cerebellum, and olfactory lobe were analyzed. Although the fatty acid compositions of the sulfatide and gangliosides were significantly different in the three parts of the brain, relatively little difference was observed in the fatty acids of glycolipids between the safflower group and the perilla group, suggesting that gross changes in brain glycolipids are not responsible for the differences in learning abilities between these dietary groups.

Animals↗