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Biomedical subjects

N Maeda

Publications and source records attributed to N Maeda.

At least 487 records · Page 27Linked to original sources
PubMed1989

Augmentation of human cytotoxic T lymphocytes against autologous tumor by a factor released from human monocytic leukemia cell line.

A human acute monocytic leukemia cell line, THP-1, releases a factor which activates human cytotoxic (killer) T lymphocytes (CTL) against autologous tumor in vitro. The factor, named cytotoxic (killer) T cell activating factor (KAF), is an acidic protein of 70,000 to 100,000 dalton molecular size. Peripheral blood leukocytes from two patients, bearing epithelioid sarcoma or malignant schwannoma, were cultured for 7 days with individual autologous tumor to induce CTL directed to the corresponding tumor. Monocyte-depleted peripheral leukocytes generated lesser CTL activity than the monocyte-containing leukocyte population. However, the KAF was able to replace the monocyte function. The KAF acted at the CTL generation phase as well as the effector phase. The KAF-activated killer cells possessed CD4-8+ surface phenotype. The CTL killed autologous tumor or other unrelated tumor cell lines only when they shared some of the HLA class I antigens. It was also demonstrated that the KAF does not activate killer cells without proper antigenic stimuli, because the KAF-augmented CTL possess specificity against autologous tumor or other HLA-A or -B matched tumor cell lines. The therapeutic applicability of human KAF for anti-tumor CTL therapy against autologous tumor is discussed.

Adult↗
PubMed1989

Rheological properties of erythrocytes in recombinant human erythropoietin-administered normal rat.

Recombinant human erythropoietin [rhEPO (180 iu/micrograms); 1 or 10 micrograms polypeptide equivalent/kg] was intravenously administered daily to 6-week-old normal rats for 1 week. Rheologically, (1) blood viscosity at shear rate of 40-380 s-1 increased in a manner entirely dependent upon the haematocrit, (2) no change in erythrocyte deformability was detected by high shear rheoscopy, and (3) the velocity of rouleau formation in autologous plasma (at 7.5 s-1) decreased. Haematologically, rhEPO administration induced considerable polycythaemia with reticulocytosis in a dose-dependent manner, accompanying increased cell volume and decreased intracellular haemoglobin concentration, thus the density distribution of erythrocytes shifted towards low specific gravity. Plasma viscosity and plasma protein composition were unaffected by rhEPO-administration. In erythrocyte metabolism, no drastic alteration in the level of 2.3-DPG or ATP was detected.

Animals↗
PubMed1989

Osteosarcoma with prominent epithelioid features.

Osteosarcoma in the metaphysis to epiphysis of the left femur of a 17-year-old male is reported. The lesion appeared osteolytic with sclerotic foci on roentgenographs, accompanied by an extensive tumor shadow in the surrounding soft tissue. While 60% of the tumor was necrotic, histological examination of the remaining viable tissue revealed that it consisted almost entirely of a sheet of epithelioid cells, separated by thin, fibrovascular septa with an alveolar-like pattern, suggestive of metastatic carcinoma. Only a few areas were characterized by malignant osteoid tissue intermingled with the above cells, showing significant positivity for bone-specific alkaline phosphatase and 5'-nucleotidase, thus permitting a diagnosis of osteosarcoma. Autopsy findings revealed that the metastatic foci were histologically similar to those of the primary tumor. Electron microscopy revealed poor development of cytoplasmic organelles, supporting possible derivation from an osteoblastic cell lineage at an early stage.

Acid Phosphatase↗
PubMed1989

Phosphorylation of P400 protein by cyclic AMP-dependent protein kinase and Ca2+/calmodulin-dependent protein kinase II.

Purified P400 protein was phosphorylated by both purified Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) and the catalytic subunit of cyclic AMP-dependent protein kinase (A-kinase). Because P400 protein was suggested to function as an integral membrane protein, we investigated the phosphorylation of P400 protein using crude mitochondrial and microsomal fractions (P2/P3 fraction). Incubation of the P2/P3 fraction from mouse cerebellum with cyclic AMP or the catalytic subunit of A-kinase stimulated the phosphorylation of P400 protein. The phosphorylation of P400 protein was not observed in the P2/P3 fraction from mouse forebrain. Cyclic AMP and A-kinase enhanced the phosphorylation of several proteins, including P400 protein, suggesting that P400 protein is one of the best substrates for A-kinase in the P2/P3 fraction. Although endogenous and exogenous CaM kinase II stimulated the phosphorylation of some proteins in the P2/P3 fraction, the phosphorylation of P400 protein was weak. Immunoprecipitation with the monoclonal antibody to P400 protein confirmed that the P400 protein itself was definitely phosphorylated by the catalytic subunit of A-kinase and CaM kinase II. A-kinase phosphorylated only the seryl residue in P400 protein. Immunoblot analysis of the cells in primary culture of mouse cerebellum confirmed the expression of P400 protein, which migrated at the same position on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as that in the P2/P3 fraction. Incubation of the cultured cerebellar cells with [32P]orthophosphate resulted in the labeling of P400 protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Prolonged degeneration of muscle spindles in the masseter muscle after treatment of developing mice with the local anesthetic lidocaine hydrochloride.

The effect of lidocaine-HCl on muscle spindles in the masseter muscle of developing mice was investigated. Repeated injections of mice with anesthetic in the short term decreased the diameters of primary endings, intrafusal muscle fibers and outer capsules in the equatorial regions of muscle spindles, and caused a drop in the succinic dehydrogenase activity in intrafusal muscle fibers of the muscle spindles. In addition, the diameters did not recover to the control value even after about 10 weeks following cessation of anesthetic treatment. Thus, the present results suggest that repeated use of lidocaine-HCl in developing animals may cause dysfunction of the skeletal muscles.

Animals↗
PubMed1989

Long-term observations of the masseter muscle following single or repeated injections of lidocaine hydrochloride into developing mice.

Effects of lidocaine-HCl on extrafusal muscle fibers in the masseter muscle of developing mice were studied histologically and morphometrically. In the affected region, many extrafusal muscle fibers were circular and smaller in diameter than unaffected extrafusal muscle fibers, and the SDH activity of the affected fibers was very irregular. In lidocaine-HCl injected groups, the ratios of extrafusal muscle fibers with central nuclei to total extrafusal muscle fibers were higher than those in the saline solution-injected groups. The diameters of extrafusal muscle fibers in the masseter muscle treated with lidocaine-HCl were smaller than those in the saline solution-injected groups. These changes in the muscle with lidocaine-HCl continued for 45 days after a single injection. Five injections of lidocaine-HCl into developing mice caused long-term degeneration of the masseter muscle. Thus, the present study suggests that a local anesthetic agent caused degeneration of immature muscle fibers of the masseter muscle in developing mice and may result in long-term decrease of masticatory capacity. Therefore, lidocaine-HCl may inhibit the synchronized development of masticatory organs in developing animals.

Animals↗
PubMed1989

Etiology of nasal polyps associated with aspirin-sensitive asthma.

It is well known that nasal polyps occur at high frequency in aspirin-sensitive asthma (ASA). Their etiology, however, remains obscure. Therefore, histopathologic observations and measurements of arachidonic acid metabolites were carried out to investigate the etiopathogenesis of nasal polyps in ASA. Abundant eosinophils and degranulated mast cells were found in the tissue of nasal polyp-associated ASA cases. Electron-microscopic analyses of these eosinophils revealed that high-electron-dense material had disappeared from the cytoplasmic granules' central crystalloids. Arachidonic acid metabolites (PGE2, PGF2, 6-keto-PGF1 and TXB2) from the cyclooxygenase pathway were measured via gas mass-chromatography. Leukotrienes (LTC4 and LTD4) from the lipoxygenase pathway were measured via HPLC-radioimmunoassay. Especially noteworthy are the high level of leukotrienes and low level of prostaglandins in nasal polyp-associated ASA. The etiopathogenesis of nasal polyps in aspirin-sensitive asthma is postulated.

Arachidonic Acid↗
PubMed1989

Lack of effect of indomethacin and captopril on protein-induced glomerular hyperfiltration in normal subjects.

We examined the possible roles of renal prostaglandins, renin-angiotensin and the kallikrein-kinin system in protein-induced glomerular hyperfiltration in normal subjects. The normal subjects were divided into three groups, i.e., control, indomethacin-treated and captopril-treated groups. Protein loading (0.6 g/kg BW as protein) resulted in a significant increase in glomerular filtration rate (GFR) from a baseline of 98 +/- 8 ml/min/1.73 M2 to 135 +/- 13 (P less than 0.01) in the control group. In both the indomethacin and captopril groups, significant elevations of GFR were observed after the test meal. The urinary kallikrein excretions after the meal were not significantly different from those for preloading in all groups. These results suggest that renal prostaglandins, renin-angiotensin and the kallikrein-kinin system may be less involved in protein-induced glomerular hyperfiltration in normal subjects.

Adult↗
PubMed1989

[Penetrating keratoplasty and cataract surgery].

Of 46 eyes undergoing simultaneous penetrating keratoplasty and cataract extraction, 25 grafts (54%) remained clear with an average follow-up of 37 months. This low success rate can be party explained by the fact that more than 50% of our patients had unfavourable ocular conditions preoperatively. In case of simultaneous procedures, methods of cataract extraction (ICCE or ECCE) did not have any significant affect on the rate of clear grafts. In eyes with favourable ocular conditions preoperatively, the rates of clear grafts were similar (approximately 75%) in cases of simultaneous operation (21 eyes) and separate operation (8 eyes).

Adult↗
PubMed1988

Molecular genetics of the apolipoprotein B gene in pigs in relation to atherosclerosis.

Immunologically defined alleles of the pig apolipoprotein B (ApoB) locus (apoB) are correlated with different blood cholesterol levels and predisposition towards premature coronary heart disease. We show here that these alleles are associated with differences in the apoB gene by identifying six restriction fragment length polymorphisms at the pig apoB locus. We have sequenced a 2.4-kb fragment encompassing exons 11 through 14 of one allele, and 7.1 kb from the 3' one-third of exon 26 to about 1 kb past the last exon from another allele. The decoded amino acids of the pig and human ApoB proteins are identical at 70% of these positions. One region close to the C-terminus of the protein is surprisingly different in pigs and humans (57% identity) but the C-terminal region is relatively well conserved (74% identity). Neither of the two putative low-density lipoprotein (LDL) receptor-binding sites is completely conserved in pigs and humans, but identical stretches of amino acids occur near these sites more frequently than in the other sequenced regions. We compare the nucleotide sequences of the region encompassing the putative LDL receptor-binding sites from four pig alleles, including one implicated directly in atherosclerosis. None of the differences appears to account for the hypercholesterolemic phenotype. We conclude that significant differences in the physiology of LDL particles result from changes outside the putative receptor-binding region.

Alleles↗