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Biomedical subjects

N Higashi

Publications and source records attributed to N Higashi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Endocytosis of poly(ethylene oxide)-modified liposome by human lymphoblastoid cells.

Egg PC liposome as reconstituted with poly(ethylene oxide)-bearing lipid (coded as PEO-lipid (n = 15)) was remarkably endocytosed by Jurkat cell, which was a lymphoblastoma derived from human T cell. To confirm the endocytosis, two kinds of fluorescent probes (FITC-dextran and octadecyl rhodamine B) were employed. The former was loaded in the aqueous phase of the liposome, while the latter was embedded in the liposomal membrane. Both probes were found coincidentally at the same site in the cytosol, clearly suggesting that whole liposome entered the cell. The endocytosis was most obvious when PEO-lipid (n = 15) was employed above 50 mol%. FITC-Dextran entered the cell was found small dots in the cell, not dispersive. Even when octadecyl rhodamine B was used, no membrane fluorescence was observed at all. The uptake closely related to the cell metabolism as affected by the culture temperature and serum in the incubation medium. Furthermore, the addition of cytochalasin B completely prohibited the cell uptake of liposomes.

Cell Membrane Permeability↗
PubMed1995

Involvement of inflammatory cytokines in a delayed-type hypersensitivity reaction.

We previously reported the amino acid sequence of the human macrophage chemotactic factor with a molecular weight of 1000 (MCF-1) was WLGREDGSE. In this study we examined the roles of MCF-1 and tumor necrosis factor (TNF) in a guinea pig delayed-type hypersensitivity (DTH) reaction. When macrophage chemotactic activity (MCA) in a skin extract was subjected to gel filtration, only the activity with a molecular weight of 1000 was significantly inhibited by anti-human MCF-1 mAb (7-3 mAb). Both MCA and TNF activity were detected in skin extracts from DTH inflammation sites where the specific antigen was injected. Both activities were produced at the early DTH reaction stage. In contrast, MCF-1 was produced at the late DTH reaction stage. The erythema was suppressed significantly either by anti-guinea pig TNF Ab or by 7-3 mAb, suggesting the roles of these two cytokines in a DTH reaction.

Amino Acid Sequence↗
PubMed1995

Phenotypic properties and cytokine production of skin-infiltrating cells obtained from guinea pig delayed-type hypersensitivity reaction sites.

In this study, skin-infiltrating cells were prepared from guinea pig delayed-type hypersensitivity reaction sites, and their phenotypic properties and cytokine production were examined. Our cell preparations contained around 45% nonspecific esterase-positive cells and a few skin-derived cells. Skin-infiltrating cells produced TNF activity and macrophage chemotactic activity (MCA), whereas resident skin cells produced much lower activity. The highest TNF activity was produced by skin-infiltrating cells at 2 hr after antigen injection. In contrast, a larger amount of MCA was produced by skin-infiltrating cells at 24 and 48 hr than at 2 hr after antigen injection. These kinetics were in good agreement with our previous results regarding cytokine activity in skin extracts. Gel filtration analysis and neutralization assay with a monoclonal antibody against human macrophage chemotactic factor with a molecular weight of 1 kDa (MCF-1) indicated that a guinea pig homologue of human MCF-1 was partially responsible for the MCA.

Animals↗
PubMed1995

[Carbon-11 labeled diacylglycerol for signal transduction imaging by positron CT: evaluation of the quality and safety for clinical use].

To elucidate the synaptic transmission in the neural system, we have been developing fundamental studies for intracellular signaling. For clinical application of carbon-11 labeled diacylglycerol (1-[1-11C]butyryl-2-palmitoyl-rac-glycerol: 11C-DAG) using positron emission computed tomography (PET), we evaluated the quality and the safety of 11C-DAG as the solution for injection. As a result, 11C-DAG was synthesized within 50 minutes, including the preparation step for injection. The half life time and energy spectrum of 11C-DAG were the same as the physical character of carbon-11, and other radioisotopes were not detected. In the quality control, 11C-DAG solution was negative in the examination of bacterial contamination and the pyrogen test in three successive synthesis procedures. In the acute toxicity test by administration of 11C-DAG and 100 mumol/kg of non-radioactive DAG to the rat intravenously, the systemic condition of the rat was not changed and no abnormalities were found in any organ 24 hours after administration. These findings indicated the safety of 11C-DAG solution. Clinical application of 11C-DAG using positron emission tomography may be useful to elucidate the dysfunction of intracellular signaling in disorders of higher cortical function such as Alzheimer disease.

Animals↗
PubMed1995

[On the hepatic artery arising from the superior mesenteric artery].

This report describes anomalous cases having the so-called gastro-lienal and the hepato-mesenteric trunks instead of the celiac and superior mesenteric arteries. These anomalous cases were divided into 4 types and 6 classes according to difference of running form of the hepatic artery as follows. Type I: This hepatic artery arose from an unusual hepato-mesenteric trunk off the aorta immediately inferior to the gastro-lienal trunk. This artery ascended behind the portal vein and splenic vein, passed around in front of the left side of the portal vein, and arrived in the liver. Type II: This hepatic artery arose from an unusual hepato-mesenteric trunk off the aorta immediately inferior to the gastro-lienal trunk. This hepatic artery ascended behind the portal vein, passed around front from the right side of the portal vein, and arrived in the liver. Type III: This hepatic artery arose from an unusual hepato-mesenteric trunk off the aorta immediately inferior to the gastrolienal trunk. This hepatic artery of III-P ascended between the portal vein and pancreas, III-A ascended in front of the pancreas. Type IV: This hepatic artery arose from an unusual hepato-mesenteric trunk off the aorta immediately inferior to the gastro-lienal trunk. This type of hepatic artery ascended behind the superior mesenteric vein, passed around in front from the right side of the portal vein, and arrived in the liver. This hepatic artery of IV-P ascended behind pancreas, IV-A ascended in front of the pancreas.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

[A case of congenital quadricuspid pulmonary valve].

The present report describes a case of congenital quadricuspid pulmonary valve, encountered during the dissection of an 84 year-old Japanese female cadaver at Kanazawa Medical University. In this case, no evidence of heart failure was found clinically or pathologically. The semilunar valve on the right posterior was the biggest and that of the left anterior was the smallest.

Aged↗
PubMed1995

[A case of the three branches of the celiac trunk arising directly from the abdominal aorta].

The present report describes the dissection of an 81 year-old Japanese female cadaver in the Kanazawa Medical University in which the celiac trunk was not present, that is, the left gastric, the splenic and the common hepatic arteries arose independently from the abdominal aorta in that order. In this case, the left gastric artery arose from the front wall of the abdominal aorta at a level between the 11th intercostal posterior and subcostal arteries. The splenic artery arose from the left front wall of the abdominal aorta about 5.0 mm below the origin of the left gastric artery. The common hepatic artery arose from the right front wall of the abdominal aorta about 4.0 mm below the origin of the splenic artery. The superior mesenteric artery dividing from the front wall of the abdominal aorta about 9.0 mm below the origin of the common hepatic artery, ran about 17.0 mm to give off the right accessory hepatic artery upwards to the right. This case belongs to type V of Morita's classification (1935), but was not described in Adachi's classification (1928). There seems to be only six such cases reported so far in Japan.

Aged↗
PubMed1994

[Carbon-11 labeled diacylglycerol for signal transduction imaging: effect of the solubilizer on the distribution and radiation dosimetry].

Carbon-11 labeled diacylglycerol (11C-DAG) has been developed as a signal transduction imaging agent for the CNS, and it can visualize the second messenger. For clinical application by positron CT (PET), the 11C-DAG solution must be prepared for intravenous injection. However, the 11C-DAG does not dissolve in water because of its lipophilicity and requires a solubilizer such as human serum albumin (HSA) and Tween 80 (TW-80). We examined the influence of these solubilizers on the tissue distribution of 11C-DAG, and estimated the radiation dosimetry. In the brain, uptake of 11C-DAG dissolved with HSA was 1.3-1.8 times higher than that of dissolved with TW-80. On the other hand, the lung and spleen showed a higher uptake of 11C-DAG using TW-80 than when using HSA. Especially, the lungs showed 20-40 times higher uptake than when using HSA. Also, the washout of radioactivity from tissue was slower, and the dose of radiation exposure was estimated to be higher, with TW-80 than with HSA. Therefore, between TW-80 and HSA with different solubilizing mechanisms, the later was suggested to be a better solubilizer of 11C-DAG.

Animals↗
PubMed1993

Chromium and tritiated thymidine releases from target cells are differential events in human monocyte/macrophage-mediated cytotoxicity.

Cytotoxic properties of human activated macrophages were investigated by measuring both 51Cr and [3H]TdR releases from prelabeled target cells. The kinetic study of macrophage-mediated cytotoxicity indicated that 51Cr and [3H]TdR releases showed a distinct time course. Next, when [3H]TdR release was measured as a parameter for cytotoxicity, pretreatment of activated macrophages with either actinomycin D or emetine remarkably decreased their cytotoxicity in a dose-dependent manner. In contrast, the pretreatment with these inhibitors had little effect on 51Cr release. Furthermore, the addition of Zn2+ in the assay medium caused the decrease in [3H]TdR release but not 51Cr release from the target cells. Taken together, our findings indicate that 51Cr and [3H]TdR releases from the target cells are induced by activated macrophages through different cytotoxic mechanisms; the former does not require RNA and protein syntheses in macrophages during coculture, whereas the latter requires them. Our findings also suggest that macrophage-derived nuclease may play an important role for inducing [3H]TdR release from the target cells.

Chromium Radioisotopes↗
PubMed1993

Identification of human T cell hybridoma-derived macrophage activating factor as interleukin-2.

Macrophages are activated by a two-step mechanism involving at least two kinds of factors, a priming and a triggering factor, to become cytotoxic to various tumor cells. In the present study, we purified macrophage-activating factor for cytotoxicity I (MAF-C I), defined as a priming macrophage activating factor (MAF), by about 1,600-fold from the culture supernatant of a human T cell hybridoma, H3-E9-6, by a series of chromatographic procedures. We identified MAF-C I activity released from H3-E9-6 cells as interleukin-2 (IL-2) from the following findings. (i) The physicochemical properties of MAF-C I and IL-2 were almost identical. (ii) Purified MAF-C I active fraction also showed T cell proliferating activity. (iii) MAF-C I activity in the purified fraction was completely neutralized by anti-IL-2 antibodies. (iv) Human recombinant IL-2 (rIL-2), at a suboptimal dose, and lipopolysaccharide (LPS) synergistically induced monocyte-mediated cytotoxicity.

Cytotoxicity, Immunologic↗
PubMed1992

Developmental change in subcellular location of Bp-1 protein with an ability to interact with both identifier sequence and its brain-specific transcript, BC-1 RNA.

Identifier sequences are transcribed to generate a brain-specific BC-1 RNA present as a ribonucleoprotein particle in the dendrites and somata of neurons. This ribonucleoprotein particle contains an identifier sequence-binding protein (Bp-1 protein). We report here the purification of BC-1 RNA and demonstrate that Bp-1 protein interacts directly with the RNA. We also demonstrate an accumulation of Bp-1 protein in the nucleus of brain cells from mouse fetus and newborns that precedes the postnatal increase in BC-1 RNA. Cytoplasmic Bp-1 protein present in a complex with BC-1 RNA increases postnatally with a concomitant decrease in nuclear Bp-1 protein. These observations suggest that Bp-1 protein may play a role(s) in the synthesis and nuclear export of BC-1 RNA.

Aging↗
PubMed1992

The 10 S BC-1 ribonucleoprotein particle contains identifier sequence-binding proteins that interact with an array of GCAAG/CTTGC motifs between split promoter sequences for RNA polymerase III.

BC-1 RNA is a brain-specific small RNA transcript of identifier sequences present in the somas and dendrites of neurons. We recently reported that the RNA is complexed with a protein(s) to form a 10 S ribonucleoprotein particle (Kobayashi, S., Goto, S., and Anzai, K. (1991) J. Biol. Chem. 266, 4726-4730). We demonstrate here that this 10 S BC-1 ribonucleoprotein particle contains a DNA-binding protein(s) (Bp-1 protein) capable of interacting with a region between split promoter sequences for RNA polymerase III within the identifier sequences. The region has short inverted repeats: a perfect octanucleotide repeat (GCGCTTGCCTAGCAAGCGC) and an imperfect heptanucleotide repeat (GCCTAGCAAGCGCAAGGC), each of which contains a GCAAG/CTTGC motif. We also demonstrate that the binding of this protein either to the array of pentamer motifs or to BC-1 RNA is mutually exclusive. The molecular masses of photo-cross-linking adducts of Bp-1 protein to a 32P-labeled GCAAG/CTTGC motif-specific probe were estimated to be about 31 and 36 kDa, indicating that two species of Bp-1 proteins may be present in the brain.

Animals↗
PubMed1992

Damage to mitochondrial respiration chain is related to phospholipase A2 activation caused by tumor necrosis factor.

Tumor necrosis factor (TNF) has been shown to be cytotoxic to tumor cell lines in vitro, but the mechanism by which TNF exerts its cell growth-regulatory effects is not known. In this report, we used various inhibitors to investigate the sequence of events that lead to cytotoxic effects of TNF on L.P3 cells, a highly sensitive, murine fibroblast cell line. Our results indicate that mitochondrial respiration chains are damaged by a hydroxyl radical at an early stage of the cell lysis after TNF treatment. This event is followed by the activation of phospholipase A2, and finally leads to cell lysis.

Animals↗
PubMed1992

Activation of human monocytes by interleukin-2 and various cytokines.

We previously reported that human macrophages cultured with IL-2 for a long period (lymphokine-activated macrophages, LAMs) showed high tumoricidal activity against human and murine leukemic cell lines through a different mechanism from lymphokine-activated killer (LAK) cells. In this report, we investigated the effects of various cytokines on the tumoricidal activity of IL-2-induced LAMs against HeLa cells. CSF-1 and IL-1 were found to enhance the tumoricidal activity of LAM in a dose-dependent manner, whereas IFN-gamma and TNF had inhibitory effects. CSF-1 in combination with a low dose of IL-2 synergistically induced LAMs with highly tumoricidal activity. We also found that monocytes from some donors that did not respond to IL-2 were differentiated to tumoricidal macrophages by treatment with a combination of CSF-1 and IL-2. Furthermore, IL-2-induced LAMs were found to produce cytotoxic factors in the culture medium when they were cocultured with tumor cells, and the cytotoxic activity in the culture supernatant of LAMs was also increased by the incubation of LAMs with CSF-1. The cytotoxicity of the supernatants from macrophages with different tumoricidal activity correlated with their cell-mediated cytotoxicity. It is suggested from these results that the cytotoxicity of LAMs is regulated by CSF-1, IL-1, IFN-gamma, and TNF, and that the production of cytotoxic molecules is involved in cell-mediated killing by LAMs.

Cytokines↗
PubMed1992

[Function, molecular structure and gene expression regulation of tumor necrosis factor and lymphotoxin].

Tumor necrosis factor (TNF, also called TNF-alpha) and lymphotoxin (LT, TNF-beta) have 32% homology in their primary structures, and it has recently been clarified that they also have closely related tertially structures. These two related cytokines share various biological functions, such as cytotoxic effect, immunomodulating effect, etc. although they produce different effects on several lymphoid, endothelial, and other cellular targets. In this paper, the structures of the two cytokines and their receptor binding sites are described. Furthermore, the structures of the two types of TNF receptors, as well as their role in TNF mediated signal transduction, and possible second messengers responsible for TNF action are also discussed.

Humans↗
PubMed1992

[On the fenestration of the vertebral and basilar arteries].

The fenestration of the vertebral and basilar arteries was investigated macroscopically in 370 human cases. Altogether 43 fenestrations were found in 32 (8.6%) out of 370 cases. The fenestrations could be divided in three groups according to the position where the fenestration appeared. Group I was the fenestration observed along the vertebral artery (Fig. 1), and 7 such fenestrations were found in 6 (1.6%) out of 370 cases; 3 fenestrations among them were located on the right side, 2 were located on the left side and 1 was found on the bilateral vertebral arteries. In 4 out of 7 fenestrations in this group, the hypoglossal nerve was found passing through the fenestration. Group II was the fenestration observed along the basilar artery (Fig. 2), and 26 fenestrations of this type were found in 20 (5.4%) out of 370 cases: 23 fenestrations (88.5%) were located at the caudal half, 3 (11.5%) were located on the rostral half of the basilar artery (Fig. 5). A close relation was indicated between the side on which the fenestration appeared in the basilar artery and the largeness in caliber of the vertebral artery of either side. Group III was the fenestration observed at the lateral area of the vertebral and basilar arteries (Fig. 3), and 10 fenestrations of this type were found in 9 (2.4%) out of 370 cases; all the fenestrations were located on the right side. In this group, the hypoglossal nerve was observed passing through the fenestratin in 4 out of the 10 fenestrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗