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Biomedical subjects

M Fukuda

Publications and source records attributed to M Fukuda.

At least 1,189 records · Page 66Linked to original sources
PubMed1985

Structures of glycosphingolipids isolated from human granulocytes. The presence of a series of linear poly-N-acetyllactosaminylceramide and its significance in glycolipids of whole blood cells.

Structures of glycolipids isolated from human granulocytes were elucidated by fast atom bombardment-mass spectrometry, methylation analysis, and exo- and endoglycosidase treatment. All neutral glycolipids, with saccharide residues ranging from 2 to 10, were found to have linear N-acetyllactosaminyl backbones. The majority of neutral glycolipids contain one or two fucosyl residues attached to N-acetylglucosamine residues through the Fuc alpha 1----3 linkage and were reactive with the monoclonal antibody specific to Gal beta 1----4(Fuc alpha 1----3)GlcNAc, the Lex structure. Their general structure can be expressed as follows: (formula; see text) where n = 0-3. Glycolipids containing sialic acid (gangliosides) were also found to have linear N-acetyllactosaminyl backbones with sialic acid joined to this backbone by either alpha 2----3 or alpha 2----6 linkage. The gangliosides have the following general structure: (formula; see text) where n = 0-3. The ceramide was composed of sphingosine with d18:1 as the long-chain base and C16:0 (as a major component) or C24:1 (as a minor component) fatty acid. Analysis of glycolipids isolated from granulocytes, erythrocytes, and whole blood cells revealed that, among the glycolipids prepared from the whole blood cells, dihexaosylceramide, lactoneotetraosylceramide, and the above described linear lactoneo series neutral glycolipids are present in granulocytes but barely present in erythrocytes.

Antibodies, Monoclonal↗
PubMed1985

Regulation of glycophorin gene expression by a tumor-promoting phorbol ester in human leukemic K562 cells.

We have previously shown that treatment of the human leukemic cell line K562 with the tumor promoter 12-O-tetradecanoyl phorbol 13-acetate (TPA) leads to a reduction in the expression of two surface glycoproteins, Gp-105 and glycophorin (Fukuda, M. (1981) Cancer Res. 41, 4621-4628). In this report, we examine the mechanism for reduction of glycophorin expression. By immunoprecipitation of metabolically labeled proteins, we found an 11-fold reduction in the incorporation of [3H]glucosamine into glycophorin after 48 h of TPA treatment. This was found to closely correlate with a reduction in [35S]methionine incorporation, suggesting that regulation occurs at the level of protein synthesis and not glycosylation. We also found that TPA decreased the incorporation of [3H]glucosamine into glycophorin in another leukemic cell line, HEL. A time course showed that there was a 3-fold reduction in glycophorin biosynthesis as early as 4 h after TPA treatment. The level then decreased to approximately 10% of the untreated control levels after 12 h of treatment. The reduction in glycophorin biosynthesis was found to be reversible following removal of TPA from the culture medium. By immunoprecipitation of in vitro translation products directed by purified total cellular RNA, we found that there is a corresponding decrease in glycophorin mRNA activity. Glycophorin mRNA activity was extensively reduced as early as 1 h after TPA treatment and by 12 h was nearly undetectable. Interestingly, the size of the primary translation product was found to be 8 kDa larger than the fully processed apoprotein. These results are consistent with the transcriptional regulation of glycophorin expression by TPA.

Cell Line↗
PubMed1985

Application of immunoblotting to serum protein phenotyping with reference to alpha 2HS-glycoprotein (AHS) typing of bloodstains.

Sera and bloodstain extracts were subjected to isoelectric focusing in polyacrylamide gels. The focused proteins were transferred to nitrocellulose membranes by diffusion or electrophoretically, then allowed to react with specific antiserum and, after washing, with peroxidase-labeled anti-rabbit IgG. The immune complexes formed on the membranes were detected with 4-chloro-1-naphthol and hydrogen peroxide. Serum group-specific component, alpha 2HS-glycoprotein, the sixth and the seventh component of complement, factor 13B, and plasminogen could be phenotyped with high sensitivity. Bloodstains as old as 6 months could be correctly typed for alpha 2HS-glycoprotein by the blotting technique.

Blood Grouping and Crossmatching↗
PubMed1985

Computed tomographic and histopathological studies of pontine glioma.

Correlative study of computed tomography (CT) and pathologic findings was performed in eight cases of pontine glioma. All patients except one had chemotherapy and radiotherapy, with no surgical intervention. On initial CT scans, all patients had hypodense lesions in part or the whole of the pons, and there was evidence of mass effect. Four of eight cases showed contrast enhancement. After chemotherapy and radiotherapy, swelling of the pons and the width of the hypodense areas decreased. The hypodense areas sometimes became isodense in correlation with clinical amelioration. After several months of remission in responding cases, ring-enhanced lesions reappeared at the primary site, together with recurrent neurological signs. Pathological study postmortem was focused on the histological counterparts of the CT findings of central and perifocal hypodense areas and contrast enhancement. In six of seven treated cases, the central hypodense area surrounded by ring enhancement was shown to be coagulation necrosis. Higher cellularity and hypervascularity with glomeruluslike structures of small vessels were generally observed in enhanced areas. The areas diffusely infiltrated by tumor cells, but not enhanced in CT scans, had few abnormal vessels. Tumor cells were seen not only in hypodense areas around the enhanced portion but also in areas far beyond the enhanced portion. Exophytic expansion of tumor was observed in two cases on postmortem examination. One of these was detected by CT scans before death.

Astrocytoma↗
PubMed1985

Cell proliferation and cell loss in intramucosal signet ring cell carcinoma of canine stomachs induced by N-ethyl-N'-nitro-N-nitrosoguanidine.

Signet ring cell carcinoma was induced in canine stomachs by N-ethyl-N'-nitro-N-nitrosoguanidine, and modes of cell proliferation and turnover in the carcinoma were studied by 3H-thymidine autoradiography in conjunction with morphometric analysis. From 2 to 15 months after the cessation of 8 months carcinogen treatment, carcinomas in an early stage were obtained. Most of the cancer tissues confined to the lamina propria showed a layered structure. This comprised three layers; the superficial and the deep layer were composed of signet ring cells, and the middle layer was composed of small round cells. The dogs were labeled with 3H-thymidine by s.c. injection and by local infusion of the celiac artery. Flash-labeled autoradiographs revealed that most 3H-thymidine incorporating cancer cells were located around the middle layer, with a small amount of mucin. Using a pulse labeling experiment, those labeled carcinoma cells were shown to migrate from the middle layer towards the surface. Morphometric analysis of the autoradiographs showed that the small cells in the middle layer migrated upwards and produced mucin to become full-blown signet ring cells by 5.5 days. In 15 days, most labeled cancer cells in the superficial layer had disappeared. This mode of cellular turnover appeared to mimic a cell renewal system of the normal gastric mucosa. If the cancer cells turn over in this way, the tumor must grow slowly, remaining as an intramucosal cancer for a relatively long period.

Adenocarcinoma, Mucinous↗
PubMed1985

Movement and non-movement related pallidal unit activity during bar press feeding behavior in the monkey.

Activity was recorded from 358 neurons in the globus pallidus (GP) of monkeys (Macaca fuscata) during an operant feeding task consisting of 3 stages: (1) food or non-food presentation (1st stage); (2) bar pressing (2nd stage); and (3) food acquisition and ingestion (3rd stage). There were two kinds of neurons, one with high and the other with very low (almost silent), spontaneous firing rates. Two hundred and four neurons (57%) responded in one or more of the feeding stages. Of the 21 neurons which responded in the 1st stage, two responded selectively to food presentation, and 19 responded to both food and non-food visual presentation. One hundred and seventy-four neurons (49%) and 107 neurons (30%) responded in the 2nd and 3rd stages, respectively, and 106 (30%) of these were directly related to specific feeding motor acts such as arm extension, flexion, bar pressing, grasping, chewing etc. Both high and low firing neurons responded to motor acts with sharp or gradual onset. More than half of those that responded to arm extension showed laterality (contra or ipsi)- and function (extension or flexion)-dependent responses. The incidence of the motor related neurons was higher in the caudodorsal part of the GP. On the other hand, about one third, especially in the rostroventral part of the GP, showed dissociating responses in that they responded during bar pressing for food or during ingestion in an operant task, but not during bar pressing for non-food or during forcible ingestion. The magnitude of firing changes during arm extension and bar pressing depended on the nature of the food. Moreover, in trials using new food or false (model) food, firing changes during bar press appeared or disappeared within a few trials with no correlation to bar press movement. These data suggest heterogeneous functions within the GP; the caudodorsal part is strictly concerned with motor execution and preparation, while the rostroventral part is not related to motor function directly, but may rather be important in coupling internal, motivational information to the motor system.

Animals↗
PubMed1985

Topographic organization of projections from the amygdala to the hypothalamus of the rat.

Afferent fibers from the amygdala to subdivisions of lateral, ventromedial and dorsomedial hypothalamic nuclei were investigated in rat by retrograde transport of horseradish peroxidase. Small (intranuclear size) peroxidase deposits were placed in hypothalamic nuclei by iontophoresis of a tracer solution containing poly-L-alpha-ornithine which greatly limited diffusion. The medial, central and amygdalo-hippocampal nuclei of the amygdala were found to be the major donors of amygdaloid afferent fibers to the hypothalamus, but there was also substantial labeling of somata in cortical, basomedial, basolateral and lateral amygdaloid nuclei and the intra-amygdaloid bed nucleus of the stria terminalis. No fibers projected from the posterior cortical nucleus of the amygdala to the hypothalamus. Most amygdaloid projections to the lateral hypothalamic area originated in the anterior half of the amygdala, while projections to the ventromedial hypothalamic nucleus arose along the entire length of the amygdala except the posterior cortical nucleus. The amygdalo-hippocampal area projects to the medial hypothalamus. Other amygdaloid nuclei project to both the medial and lateral hypothalamic nuclei. These topographic organizations of amygdaloid afferent fibers to various subdivisions of the hypothalamic nuclei are discussed and compared with other anatomical studies on these connections.

Amygdala↗
PubMed1985

Insertion of a long KpnI family member within a mitochondrial-DNA-like sequence present in the human nuclear genome.

Structural analysis of a phage lambda Charon 4A clone carrying one of the human nuclear mitochondrial(mut)-DNA-like sequences revealed that a KpnI-family member (KpnI 5.5-kb DNA) is inserted within this sequence. The inserted KpnI 5.5-kb DNA contains several possible polyadenylation signal sequences followed by an A-rich sequence at its 3' end and is flanked by perfect 13-bp direct repeats of the duplicated mtDNA-like sequences. These structures strongly suggest that the KpnI 5.5-kb DNA is a mobile element. Comparison of the 5' terminal sequences of the KpnI 5.5-kb DNA and four other long KpnI-family DNAs so far examined, using the predicted general promoter sequence for eukaryotic tRNAs, indicates that they contain the consensus sequences for the split internal RNA polymerase III control region.

Base Sequence↗
PubMed1985

DNA content of diffusely infiltrative carcinomas in the stomach.

DNA content of diffusely infiltrative carcinomas of 15 Japanese patients, ranging in age from 38 to 65 years, was determined by cytofluorometry, using paraffin sections which were available for histological examination. Sections were stained with 0.0025% propidium iodide. By measuring the fluorescence intensity of at least 50 mitotic cells, ploidy patterns of the cancers were determined, whereas a control of the diploid DNA content was set by measuring the fluorescence intensity of mitotic cells in the non-cancerous gastric mucosa; only metaphase nuclei in the sections were considered to have a whole amount of nuclear DNA in the cytofluorometric measurement. In the present study, it was found that most of the diffusely infiltrative carcinomas consisted of a heteroploid cell line. Their stem DNA contents ranged between 2.8C and 4.8C (2C corresponds to a diploid amount of nuclear DNA). Of 15 cancers, four comprised a mosaic cancer of two different heteroploid cell lines. We encountered only one carcinoma containing a diploid cell line. However, this cancer also contained a heteroploid cell line. Six cancers contained a polyploid cell population, the DNA content of which was double of the stem DNA content. In most cases, the cancer cells distributed in the mucosal layer were also heteroploid, thereby suggesting a heteroploid origin of the diffusely infiltrative carcinomas.

Adult↗
PubMed1985

Elongation in the major direction of tobacco mosaic virus assembly.

Butler and Lomonossoff [Butler, P. J. G. & Lomonossoff, G. P. (1978) J. Mol. Biol. 126, 877-882] claim that the elongation in the major direction (3'-->5') proceeds by incorporation of disk protein in tobacco mosaic virus (TMV) assembly. The strongest argument they have for this theory is the periodicity of 50 or 100 nucleotides that they observed in the banding pattern of the protected RNAs during the first few minutes of the assembly reaction. We repeated their experiment using TMV-OM (a common Japanese strain) disk protein and TMV-OM RNA. We observed a banding pattern similar to theirs, but we found the long protected RNA at 6 min to be from the 260-nm intermediate particle rather than from the full-length TMV RNA. We also carried out the assembly reaction between TMV-OM disk protein, as well as cucumber green mottle mosaic virus (CGMMV) protein, and three strains of TMV RNAs. During the course of each assembly reaction, we examined the banding patterns. We demonstrated that the banding pattern of the protected RNA differs depending on what kind of RNA is used, rather than on what kind of aggregational state the protein is in. Specifically, the similar banding pattern observed for CGMMV subunit protein was also observed for TMV disk protein in the assembly reaction with TMV (OM) RNA. We showed previously that the assembly reaction between CGMMV protein and TMV RNA proceeds by incorporation of CGMMV subunit protein. This strongly indicates that the banding pattern of the protected RNA does not arise from the stepwise addition of the 20S disk protein.

Journal Article↗
PubMed1985

Kinetic study of carboxypeptidase P-catalyzed reaction. Pressure and temperature dependence of kinetic parameters.

Detailed kinetic analyses of carboxypeptidase P-catalyzed reactions were carried out spectrophotometrically using 3-(2-furyl)acryloyl-acylated peptide substrates. The maximum kcat/Km was observed at around pH 3.5 for the synthetic peptide substrates. The kcat/Km value decreased with increasing pH, with an apparent pKa value of 4.43. However, the maximum kcat was observed at neutral pH (pH congruent to 6) and the pKa was 4.49. These apparently different pH profiles for kcat/Km and kcat of this enzyme were due to the decreasing Km value in the acid pH region. The pressure and temperature dependences of these kinetic parameters were also measured. N-Benzoylglycyl-L-phenyllactate (Bz-Gly-OPhLac) gave dependences similar to those of the peptide substrate, suggesting that there is no distinct difference in the catalytic mechanism between the peptide and the ester hydrolyses.

Carboxypeptidases↗
PubMed1985

Characterization of a membrane surface glycoprotein associated with T-cell activation.

A cell surface antigen (gp140) was previously shown to exist on T cell subsets as well as on monocytes and macrophages in normal peripheral blood. Elevated expression of this antigen was associated with immune system disorders, acute lymphocytic leukemias, and in vitro activation of T cells. The antigen could be identified with monoclonal antibody (MAb) T305. Gp140 was a biosynthetic product of T cells because it could be labeled with [3H]leucine or [3H] glucosamine. Biochemical studies of gp140 used high performance liquid chromatography with nitrocellulose blotting to isolate aliquots suitable for 125I radiolabeling and immunoprecipitation to demonstrate: a) a reduction in m.w. of gp140 KD to 90 KD after deglycosylation by trifluoromethanesulfonic acid, b) alteration of isoelectric point from 4.1 to 5.7 after neuraminidase treatments, c) absence of N-linked sugars based on resistance to endoglycosidase F, d) resistance to trypsin and chymotrypsin digestion but susceptibility to pronase, and e) presence of sialic acid and lactosaminoglycan as O-linked sugars. Gp140 could be labeled with the periodate/NaB[3H]4 technique, indicating its similarity to a class of sialoglycoproteins previously described on activated T-cells in mouse and man. The antigenic epitope recognized by MAb T305 contains sialic acid linked (2----3) to galactose; however, periodate oxidation of the exocyclic ring of sialic acid did not affect binding by MAb T305. In an attempt to determine the functional role of gp140, we tested the ability of MAb T305 to block: a) proliferation of peripheral blood lymphocytes to mitogens, b) response to interleukin 2 (IL 2) of an IL 2 dependent T cell line, and c) growth of a T-ALL derived cell line. No inhibition of proliferation or growth was noted. Although the function of gp140 remains unknown, its association with lymphocyte activation and certain disease states suggests that it may provide a target for modulation of the immune response. These studies characterize the structural features of gp140 and further define the epitope recognized by MAb T305.

Animals↗