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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 1,063 records · Page 59Linked to original sources
PubMed1988

Production of interleukin-3 from a T-cell neoplasm.

We have established a new T-cell line (CL-8313) that produces interleukin-3 from the spleen cells of mice with a radiation-induced myeloproliferative disorder. IL-3 activity was detected at an extremely high level in the culture medium of the CL-8313 cell line in the absence of any exogenous stimulator. A large amount of IL-3 transcript also was demonstrated in CL-8313 cells. BPA- and CSF-activity was detected at a high level in the culture medium of the CL-8313 cell line. Southern blot analysis of high molecular weight DNA from the CL-8313 cells showed they had unique rearrangement of the antigen receptor beta chain gene. Therefore, we concluded that CL-8313 cells belonged to T-lineage lymphocytes and constitutively produced a high level of IL-3.

Animals↗
PubMed1988

Establishment of a hemopoietic stimulating factor producing murine leukemia cell lines: pathogenesis of granulocytosis in L8313 bearing mice.

Thy 1.2+ cells of L8313 leukemia bearing mice were previously shown to produce granulocyte macrophage colony stimulating activity (GM-CSA) and interleukin-3 (IL-3). Cell lines with the Thy 1.2+ phenotype were established from spleen cells of the leukemic mice, and were designated STIL-3 C5 and STIL-3 D10. They produced and released GM-CSA and IL-3 activities in culture supernatant. C5 cells were phenotypically Thy 1.2+ and Lyt 2.1+ with rearrangement of the T-cell receptor beta chain gene also being identified. D10 was Thy 1.2+ and L3T4+ with T-cell receptor beta chain gene rearrangement not detectable. Since the same sized rearranged bands were observed between C5 and L8313 leukemic mouse spleen cells, it is indicated that C5 cells are derived from the leukemic cells. Inoculation of these cells into mice induced granulocytosis. These results indicated that L8313, which was thought to be a "granulocytic leukemia", is actually a T-cell leukemia, whose granulocytosis is a leukemoid reaction induced by normal hemopoietic cells responding to the hemopoietic stimulating factors, GM-CSA and IL-3, produced by the leukemic T cells. Thus, L8313 should be known as a T-cell leukemia associated with granulocytosis.

Animals↗
PubMed1988

Changes in intracranial pressure elicited by electrical stimulation of the brainstem reticular formation in spinal cats with vagotomy.

The momentary changes in intracranial pressure (ICP) were explored using electrical stimulation of the brainstem reticular formation and the nucleus fastigii of the cerebellum in cats under artificial ventilation after spinalization (C2) and vagotomy. Regions that yielded an increase in ICP in the arterial pressor area were: the central part of the pontine recticular formation, the dorsal medullary reticular formation, the central part of the medullary reticular formation, and the nucleus fastigii of the cerebellum; and one region in the arterial depressor area was the paramedial and ventral medial region of the medullary reticular formation. Since the arterial blood pressure and respiration was maintained constant during electrical stimulation by spinalization and vagotomy, the increase in ICP in the cranium, a semi-closed box, momentarily reflected an increase in cerebral blood volume due to cerebral vasodilatation. It is suggested that excitation of cell bodies or fibres within these regions may produce cerebral vasodilatation.

Animals↗
PubMed1988

Effects of natural human interferon-alpha, -beta and -gamma on interleukin 2 production in human peripheral lymphocytes.

Effects of interferon (IFN) on PHA-induced interleukin 2 (IL-2) production by human peripheral mononuclear cells were studied comparatively with natural human IFN-alpha, IFN-beta and IFN-gamma, using an equivalent unit of their antiviral activity ranging from 10 to 1000 IU/ml. IL-2 activity was assessed in cultures with or without IFN by a standard bioassay using murine CTLL-2 cells. PHA-induced production of IL-2 in cultures of peripheral mononuclear cells was unaltered or slightly suppressed by the simultaneous presence of IFN-alpha and IFN-beta. The effect was the same, whether or not indomethacin was present in the cultures. In contrast, the addition of IFN-gamma to the PHA-stimulated cultures markedly enhanced IL-2 production, while IFN-gamma per se had no effect on IL-2 production in the absence of PHA. The enhancement of IL-2 production due to IFN-gamma was more marked in cultures which did not include indomethacin than in cultures which contained indomethacin (1 x 10(-6) M).

Humans↗
PubMed1988

Application of a human T cell line derived from a Sézary syndrome patient for human interleukin 4 assay.

Interleukin 4 (IL-4) is a multi-functional biological regulator molecule. We developed a simple assay system for human IL-4, using a IL-2-dependent T cell line designated Sez 627 cell line. Sez 627 cells were found to respond only to human IL-4 and human IL-2, but not to other available lymphokines. In combination with mouse IL-2-dependent CTLL-2 cell line, which responds to both human and murine IL-2 but not to human IL-4, human IL-4 activity can be discriminated from human IL-2 activity.

Biological Assay↗
PubMed1988

Human T cell lines established from the cerebrospinal fluid of patients with human T lymphotropic virus type I-associated myelopathy (HAM).

T cell lines were established from the cerebrospinal fluid (CSF) lymphocytes of two patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). These two interleukin-2 (IL-2)-dependent T cell lines have been cultured for more than 8 months without any accessory cells. The surface phenotype of these cells was CD2(+), CD4(+), CD8(-), Ia(+) and Tac(+). Southern blot hybridization analysis revealed the presence of HTLV-I provirus in these cells and C-type retrovirus particles were identified by electron microscopy. These findings indicate the presence of HTLV-I infected helper T lymphocytes in the CSF of the patients with HAM. These HTLV-I(+) T cell lines may be valuable for investigating the possible neutrotropism of HTLV-I and the role of HTLV-I in the pathogenesis of HAM.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

Analysis of the provirus genome integrated in T cell lines established from the cerebrospinal fluid of patients with human T lymphotropic virus type I-associated myelopathy (HAM).

T cell lines were established from the cerebrospinal fluid (CSF) lymphocytes of three patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). To elucidate the possible changes of the provirus nucleotide sequences integrated in HAM-derived T cell line cells, DNA from these cells was digested with PstI, which cleaved the provirus genome of HTLV-I at several sites, and three common bands were detected by Southern blot analysis in all cases. These bands were identical in size to those detected in T cell lines established from peripheral blood lymphocytes of adult T cell leukemia (ATL) patients. These results were confirmed with restriction enzymes HindIII and BamHI. These findings suggest that the provirus genome detected in T cell lines derived from CSF of HAM patients is identical to HTLV-I.

Adult↗
PubMed1988

HLA-DP typing by analysis of DNA restriction fragment length polymorphisms in the HLA-DP beta subregion.

HLA class II antigens are encoded in the HLA-D region and are highly polymorphic. Southern hybridization technique was used to analyze restriction fragment length polymorphisms (RFLPs) in the DP beta gene and an attempt was made to correlate these with DP haplotypes derived from primed lymphocyte typing (PLT) analysis. Digestion of DNA from 32 Epstein-Barr virus (EBV)-transformed cell lines (of haplotypes DPw2, DPw3, DPw4, DPw5, and Cp63) with three different restriction endonucleases. Southern transfer, and hybridization to the DP beta cDNA probe revealed multiple fragments in all cell lines tested. The polymorphic patterns of these fragments were found to correlate with DP haplotypes, suggesting the possibility that the analysis of DNA RFLPs (DNA typing) in the HLA-DP beta subregion can distinguish and identify HLA-DP haplotypes.

DNA↗
PubMed1988

Effects of electrical stimulation on intracranial pressure and systemic arterial blood pressure in cats. Part I: Stimulation of brain stem.

It has been suggested that brain stem activity is involved in the occurrence of pressure waves. Different sites in the brain stem were activated by electrical stimulation in cats anaesthetized with sodium pentobarbital, to produce an increase in intracranial pressure (ICP) similar to the pressure waves. Then the effect of artificial ventilation on the occurrence of the pressure wave-like response produced under spontaneous respiration was examined since Lundberg's A-waves appear even in artificial ventilation, and B-waves are effaced during artificial ventilation. This results in a brain stem map of ICP and systemic arterial blood pressure (BP) produced by electrical stimulation during spontaneous respiration. Stimulation of the rostral medullary reticular formation produced a rise in ICP and BP in association with a change in the rhythm of the spontaneous respiration; with artificial ventilation, stimulation produced a rise in BP but ICP kept almost at the same level. However, the rise in ICP that was produced by stimulation of the caudal medullary reticular formation during spontaneous respiration also occurred with a depressor response of BP during controlled ventilation. The pressure wave-like responses could be classified, therefore, into two types. One was the response seen during both spontaneous and controlled ventilation, which we designated the 'alpha' wave. The other was the response seen only during spontaneous ventilation, the 'beta' wave. These observations suggest that the origins of A- and B-waves may be related to those of 'alpha' and 'beta' waves, respectively.

Animals↗
PubMed1988

Effects of electrical stimulation on intracranial pressure and systemic arterial blood pressure in cats. Part II: Stimulation of cerebral cortex and hypothalamus.

This experimental work was carried out to examine whether activation of autonomic cortical and hypothalamic areas by electrical stimulation is related to changes in the intracranial pressure (ICP) in cats anaesthetized lightly with sodium pentobarbital. Electrical stimulation was performed using a concentric electrode with a train of electrical pulses (pulse duration, 0.4 ms; frequency, 40 Hz; intensity, 50-400 microA). Stimulation of sites in the anterior cingulate gyrus produced a rise in ICP associated with a fall in systemic arterial blood pressure (BP) or with no change in BP. Stimulation of sites in the anterior hypothalamus produced a fall in BP with an increase in ICP. Stimulation of sites in the area extending from the anterior hypothalamus to the posterior hypothalamus produced rises in BP and ICP. These observations suggest that activation of autonomic cortical and hypothalamic areas is involved in changes in ICP.

Animals↗
PubMed1988

Concurrent changes in Dunaliella salina ultrastructure and membrane phospholipid metabolism after hyperosmotic shock.

Hyperosmotic shock, induced by raising the NaCl concentration of Dunaliella salina medium from 1.71 to 3.42 M, elicited a rapid decrease of nearly one-third in whole cell volume and in the volume of intracellular organelles. The decrease in cell volume was accompanied by plasmalemma infolding without overall loss of surface area. This contrasts with the dramatic increase in plasmalemma surface area after hypoosmotic shock (Maeda, M., and G. A. Thompson. 1986. J. Cell Biol. 102:289-297). Although plasmalemma surface area remained constant after hyperosmotic shock, the nucleus, chloroplast, and mitochondria lost membrane surface area, apparently through membrane fusion with the endoplasmic reticulum. Thus the endoplasmic reticulum serves as a reservoir for excess membrane during hyperosmotic stress, reversing its role as membrane donor to the same organelles during hypoosmotically induced cell expansion. Hyperosmotic shock also induced rapid changes in phospholipid metabolism. The mass of phosphatidic acid dropped to 56% of control and that of phosphatidylinositol 4,5-bisphosphate rose to 130% of control within 4 min. Further analysis demonstrated that within 10 min after hyperosmotic shock, there was 2.5-fold increase in phosphatidylcholine turnover, a twofold increase in lysophosphatidylcholine mass, a four-fold increase in lysophosphatidate mass, and an elevation in free fatty acids to 124% of control, all observations suggesting activation of phospholipase A. The observed biophysical and biochemical phenomena are likely to be causally interrelated in providing mechanisms for successful accommodation to such severe osmotic extremes.

Cell Membrane↗
PubMed1988

Prognostic implication of cellular DNA content in acute lymphoblastic leukemia.

To assess the prognostic value of the cellular DNA content measured by flow cytometry in acute lymphoblastic leukemia (ALL), we studied the pretreatment distribution of the DNA content in marrow blasts from 74 children with this disease. They were divided into standard- and high-risk groups according to their white blood cell counts and age at the time of diagnosis and were followed for up to 44 months. Abnormal DNA stemlines were detected in 26 children, and all of them had a hyperdiploid DNA content (DNA index of greater than 1.0). The duration of remission was significantly longer in those with hyperdiploid DNA stemlines than in those with diploid DNA stemlines in both risk groups. In the standard-risk group, the DNA content and common ALL antigen were significant prognostic factors, especially the former. In the high-risk group, the DNA content also showed an independent significant correlation with the clinical outcome.

Adolescent↗
PubMed1988

Successful treatment of a VIPoma by continuous subcutaneous infusion of somatostatin analogue (SMS 201-995).

A case with WDHA syndrome due to VIPoma is reported. Injection of somatostatin analogue SMS 201-995 was followed by prompt suppression of vasoactive intestinal polypeptide levels (VIP), decreased stool volume, and restoration of the serum potassium concentration to normal. Long-term treatment with SMS 201-995 for up to 20 weeks produced excellent clinical control and a decrease in tumour size. No adverse effects were noted except for localized pain at the site of injection. This was overcome by using a continuous subcutaneous infusion pump which also enabled the effective daily dosage to be reduced and thereby adverse reactions to be avoided.

Female↗
PubMed1988

Localization of Fc receptors on liver sinusoidal endothelium. A histological study by electron microscopy.

The localization of Fc receptors for IgG on mouse liver sinusoidal endothelium was studied in tissue sections by light and electron microscopy using peroxidase-antiperoxidase IgG complexes as ligands. Light microscopy revealed that Fc receptors were continuously present along the sinusoidal wall, but absent on the endothelium of the central vein and that of the portal area blood vessels. Electron microscopy revealed Fc receptors on both the luminal and basal aspects of the plasma membrane, far more being present on the former, on the walls of cytoplasmic fenestrae, and abundantly on the walls of coated pits and vesicles of sinusoidal endothelial cells. Fc receptors were found more frequently on sinusoidal endothelial cells than on Kupffer cells. Fat-storing cells lacked the receptors and hepatocytes showed an ambiguous result which was considered to be nonspecific.

Animals↗
PubMed1988

Temperature-sensitive Escherichia coli mutant with an altered initiation codon of the uncG gene for the H+-ATPase gamma subunit.

A mutant of Escherichia coli showing temperature-sensitive growth on succinate was isolated, and its mutation in the initiation codon (ATG to ATA) of the uncG gene (coding for the gamma subunit of H+-ATPase F0F1) was identified. This strain could grow on succinate as the sole carbon source at 25 and 30 degrees C, but not at 37 or 42 degrees C. When this strain was grown at 25 degrees C on succinate or glycerol, its membranes had about 15% of the ATPase activity of wild-type membranes, whereas when it was grown at 42 degrees C, its membranes had about 2% of the wild-type ATPase activity. Membranes of the mutant grown at 25 or 42 degrees C could bind F1 functionally, resulting in about 40% of the specific activity of wild-type membranes. The gamma subunit was identified in an EDTA extract of membranes of the mutant grown at 25 degrees C, but was barely detectable in the same amount of extract from the mutant grown at 42 degrees C. These results indicate that initiation of protein synthesis from the AUA codon is temperature sensitive and that the gamma subunit is essential for assembly of F1 in vivo as shown by in vitro reconstitution experiments (S. D. Dunn and M. Futai, J. Biol. Chem. 255:113-118, 1980).

Base Sequence↗
PubMed1988

Isolation of subunits from Methanosarcina barkeri ATPase: nucleotide-binding site in the alpha subunit.

The alpha (62,000-dalton) and beta (49,000-dalton) subunits of Methanosarcina barkeri ATPase were purified to homogeneity. The subunits and ATPase complex were trypsinized in the presence of various nucleotides. ATP and ADP changed the trypsin sensitivity of the alpha subunit in the complex and isolated forms, suggesting the presence of a nucleotide-binding site in the alpha subunit.

Adenosine Diphosphate↗