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S Doi

Publications and source records attributed to S Doi.

At least 145 records · Page 8Linked to original sources

An alpha-specific gene, SAG1 is required for sexual agglutination in Saccharomyces cerevisiae.

Seven alpha-specific mutants specifically defective in sexual agglutinability were isolated. The other alpha mating functions exhibited by these mutants, designated sag mutants, such as the production of alpha pheromone and response to a mating pheromone, were normal. While the MAT alpha sag1 cells did not agglutinate with wild-type a cells, the MATa sag1 cells did, indicating that the SAG1 gene is expressed only in alpha cells. The mutations were semi-dominant and fell into a single complementation group, SAG1, which was mapped near met3 on chromosome X. Complementation analysis showed that sag1 and ag alpha 1, the latter being a previously reported alpha-specific mutation, were mutations in the same gene.

Genes, Fungal↗

Administration of recombinant IL-2 augments the level of serum IgM in an IL-2 deficient patient.

A patient with ataxia telangiectasia was treated with recombinant interleukin-2 (rIL-2) and the resulting immunological effects evaluated. The patient lacked IL-2 production, and immunoglobulin synthesis was also impaired. Treatment with IL-2 selectively increased serum IgM without any significant side effects. Therapy also restored B-cell function in vitro. IgM production as well as the proliferative response to Staphylococcus aureus strain Cowan I. These results suggest that IL-2 treatment may correct both T-cell and B-cell defects.

Adolescent↗

Chloroquine, a lysosomotropic agent, inhibits zygote formation in yeast.

Haploid cells of opposite mating type of Saccharomyces cerevisiae conjugate to form zygote. During the conjugation process, the degradation or reorganization of the cell wall and the fusion of the two plasma membranes take place. Since chloroquine inhibits cellular events associated with the reorganization of the plasma membrane, the effect of the drug on conjugation was studied. Chloroquine at a concentration, at which cell growth was not retarded, inhibited zygote formation, while it did not affect other mating functions, such as sexual agglutination, production of and response to mating pheromone. Cells in a mating culture containing chloroquine formed no "prezygote" suggesting that they were not prepared for entering into fusion process. The inhibitory effect of chloroquine was reversible as cells formed zygote when they were washed after treatment with chloroquine. Zygote formation was unaffected in cells possessing chloroquine within vacuoles after incubation with the drug in complete medium (YPD) at pH 7.5, followed by washing. This suggests that chloroquine inhibits zygote formation by adsorbing to the plasma membrane of S. cerevisiae.

Adsorption↗

Rapid clearance of Plasmodium yoelii-infected erythrocytes after exposure to the ionophore A23187.

1. The effects of Ca2+ and the calcium ionophore A23187 on the intraerythrocytic development of the asexual forms of Plasmodium yoelii were examined. 2. Erythrocyte-free parasites obtained by saponin lysis of infected cells remained viable after exposure to 1 mM Ca2+. 3. A23187 inhibited the growth of P. yoelii and the inhibition was augmented by Ca2+ in cells infected with parasites at young stage of development. 4. A23187-treated infected cells disappeared from the circulation shortly after intravenous injection and this disappearance was profound in infected cells treated with the ionophore in the presence of Ca2+.

Animals↗

Transport processes of 2-deoxy-D-glucose in erythrocytes infected with Plasmodium yoelii, a rodent malaria parasite.

The transport processes of D-glucose in Plasmodium yoelii-infected mouse erythrocytes were investigated using 2-deoxy-D-glucose (2DOG), a non-metabolizable analogue of D-glucose. Infected cells showed an increase in the uptake of 2DOG compared to uninfected controls, and an effect which was more prominent in cells with mature-stage parasites. Kinetic studies measuring the initial rates of 2DOG uptake revealed two components in infected cells with late trophozoite and schizont-stage parasites: a simple diffusion system and a carrier (transporter)-mediated system. The transporter was common for D-glucose and 2DOG and had a kinetic constant indicating a high affinity for 2DOG (the Km = 0.18 mM and the Vmax = 0.61 mmol/10(10) cells/min), as compared to the constant of the mouse erythrocyte carrier (the Km = 10 mM and the Vmax = 1.8 mmol/10(10) cells/min). Determination of the distribution of [3H]2DOG in infected cells and experiments with metabolic inhibitors indicated that the simple diffusion system localizes in the membrane of host cells and the transporter in the parasite plasma membrane. The parasite glucose transporter was much less sensitive to cytochalasin B than that of the host cells and the uptake of 2DOG via the transporter was dependent on energy. Based on these findings, the following features emerge: D-glucose first gains access to the cytosol of infected erythrocytes via the simple diffusion system, which appears after infection by the parasite, and an active uptake against the concentration gradient takes place at the parasite plasma membrane via the parasite glucose transporter in an energy dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Immunohistochemical analysis of peripheral T-cell lymphoma in Japanese patients.

The authors immunohistochemically analyzed the phenotype of 40 cases of peripheral T-cell lymphoma, including 12 adult T-cell leukemia/lymphoma (ATL) cases. Molecular genetic analysis of the T-cell receptor beta-chain and immunoglobulin heavy chain genes were also applied to cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like lymphoma and so-called Lennert's lymphoma. Twenty non-ATL lymphomas expressed a helper/inducer phenotype, whereas only one extranodal case expressed a suppressor/cytotoxic phenotype. Three cases had a CD4-CD8- phenotype, and two cases a CD4+CD8+phenotype. No specific relationship between morphologic characteristics (LSG classification) and phenotype was found among non-ATL lymphomas. Six of eight AILD-like lymphomas had a helper/inducer phenotype. Monoclonality of neoplastic T-cells was demonstrated in six of the seven cases of AILD-like lymphoma by molecular genetic analysis. Two cases of Lennert's lymphoma also showed a helper/inducer phenotype and rearrangement of the T-cell receptor beta-chain gene. Serologically defined ATL cases had a helper/inducer phenotype except in one case that expressed both CD4 and CD8. None of the ATL cases had the CD7 antigen in this study using WT 1 as a CD7 antibody, which is in contrast with the non-ATL lymphomas in which 13 of 25 cases expressed CD7. CD25, strongly detectable in all ATL cases, was negative or weakly expressed in non-ATL lymphomas. These facts suggest that non-ATL and ATL are in the different biologic state, probably resulting from the integration of human T-cell leukemia virus type I (HTLV-I), although both are derived from helper/inducer T-cells.

Antigens, Differentiation, T-Lymphocyte↗

Production of sterile transcripts of C gamma genes in an IgM-producing human neoplastic B cell line that switches to IgG-producing cells.

A human neoplastic B cell line SSK41 that expresses IgM on its surface switches spontaneously to IgG-producing cells. The SSK41 line contains a single immunoglobulin heavy-chain locus, the constant region (C) genes of which retain the germline configuration. The IgG-producing SSK41 line was purified by sorting, and shown to have undergone S-S recombination with deletion of the C mu gene. This line produced secretory and membrane-bound forms of gamma-chain mRNA. From cDNA libraries of a mixed population of IgM+/IgG+ SSK41 cells, we have isolated cDNA clones encoding the mature membrane-bound and secretory forms of the mu and gamma 1 heavy chains, all of which share the same variable region sequence. cDNA clones containing the mature gamma 3 chain were identified as well. We also isolated cDNA clones containing C gamma 1 and C gamma 3 sterile transcripts from the SSK41 line. These sterile transcripts contained additional exon sequences designated 'I' which were localized upstream of the C gamma 1 and C gamma 3 switch regions and homologous to murine counterparts. The I sequences were precisely spliced to the 5' ends of the corresponding C gamma exon sequences. These features of germline CH transcripts, i.e. the isotype specificity to class switching, location of exons, and sequences per se, are highly conserved between man and mouse.

Amino Acid Sequence↗

Plasminogen phenotypes in a Japanese population. Four new variants including one with a functional defect.

Human plasminogen (PLG) phenotypes were investigated by polyacrylamide gel isoelectric focusing followed by immunoblotting. In 5,735 plasma samples from unrelated, healthy Japanese individuals, four new variants were detected and tentatively designated PLG AOsaka, PLG BOsaka, PLG MOsaka and PLG ANara. The plasminogen concentrations and activities of the PLG phenotypes were studied. In agreement with previous studies PLG M5 was found to have a decreased activity. The new variant PLG MOsaka had a very low activity and appears to be an abnormal plasminogen with a functional defect similar to that of PLG M5.

Gene Frequency↗

Induction of repressible acid phosphatase by unsaturated fatty acid in Saccharomyces cerevisiae.

We studied the induction of acid phosphatase (APase) by fatty acids in Saccharomyces cerevisiae. S. cerevisiae has two types of APase: constitutive and repressible enzymes. The synthesis of the latter APase is normally derepressed by depletion of inorganic phosphate (Pi) in the incubation medium. Of the saturated and unsaturated fatty acids tested, linoleic, linolenic and arachidonic acids induced the synthesis of APase even in the presence of a high concentration of Pi, whereas palmitic, stearic and oleic acids did not. De novo protein synthesis but not stimulation of secretion of the enzyme was required for the induction. Genetic analyses using plasmids carrying the genes, PHO5 and PHO3, that code for repressible APase and constitutive APase, respectively, showed that linolenic acid induced the formation of repressible APase. Linolenic acid inhibited the uptake of exogenous 32Pi and simultaneously lowered the intracellular level of Pi. These circumstances indicate that linolenic acid-induced derepression of repressible APase is primarily caused by a fall in the intracellular level of Pi. However, cells that had been preincubated in the presence of a high concentration of Pi produced APase shortly after the addition of linolenic acid. It is, therefore, suggested that, as well as a normal regulatory mechanism for derepression of repressible APase, a mechanism independent of the external level of Pi participates in the induction of repressible APase by linolenic acid.

Acid Phosphatase↗

The establishment of a clinical diagnostic method of the visual evoked potentials (VEPs) in the cat: the effects of recording electrode positions, stimulus intensity and the level of anesthesia.

The establishment of characteristic wave pattern of visual evoked potentials (VEPs) in the cat was attempted in order to be aid for clinical veterinary practitioners with the evaluation of visual dysfunction. 1) The position where the largest response of the VEPs was detected was close to the midline of the occipital area in normal cats. 2) The VEPs consisted of three components with latencies within 100 msec after flash stimulus. 3) Flash stimuli of higher illumination produced VEPs of shorter latencies and increased amplitude. Intensity of more than 0.6 J was necessary to obtain stable VEP patterns. 4) The latencies of VEPs hardly changed with time course under pentobarbital anesthesia, although they showed a fluctuant variation.

Anesthesia, Intravenous↗

Cross-lineage gene rearrangements in human leukemic B-precursor cells occur frequently with V-DJ rearrangements of IgH genes.

Gene configurations of immunoglobulin (Ig), T-cell antigen receptor (TCR) beta chain, and T-cell rearranging gene gamma (TRG gamma) were studied in human B-precursor lymphoblastic leukemic cells. These cells were phenotypically classified into three developmental stages (stages II through IV) according to Nadler's criteria. All of them showed the Ig heavy chain (IgH) gene rearrangement, and 67% of the cells in stage IV had the rearranged TRG gamma, albeit seldom in other stages. We further analyzed IgH gene rearrangements in detail using upstream to DH (diversity region of IgH) region probe to distinguish DJ from V-DJ recombination. All dual genotyped cells in each stage except one case in stage II showed the V-DJ rearrangements. This suggests the cross-lineage involvement of the putative recombinase, particularly in the process of V-DJ rearrangements. We next examined the transcriptional status of Ig genes as an indirect reflection of the accessibility of these genes to the recombinase. Properly spliced IgH transcripts of normal size were observed in stage IV and surface Ig positive stage, but not in stage II nor III. However, IgH transcripts of aberrant sizes were seen in stage II, III, and also IV. Cross-lineage gene rearrangements were shown to occur frequently when normally spliced IgH gene begins to be transcribed or just before this. These findings may implicate that V-DJ or V-VDJ gene rearrangements forming functional IgH genes, induce frequently TCR or TRG gene rearrangements. We propose these dual genotypes are different in origin from those observed in stem cell leukemia.

Antigens, Differentiation, B-Lymphocyte↗

[Two cases of familial spastic paraparesis with amyotrophy of the hands].

Familial spastic paraparesis with amyotrophy of the hands was reported, and its significance in the literature was reviewed. Case 1: An 18 year-old boy, who had been suffering from spastic gait since 12 years old, noticed his hand muscle wasting distributed bilateral first interosseous muscle, thenar and hypothenar muscle at age 17. Case 2: A 20 year-old man, elder brother of case 1, who also walked in spastic manner from his childhood, developed bilateral hand muscle atrophy similar to case 1 at age 19. Clinical features of these two cases could be summarized as familial spastic paraparesis with amyotrophy characterized by hand muscle atrophy, spasticity of lower extremities with hyperreflexia and bilateral positive pathological reflexes and spastic gait. Their younger sister was also examined, who showed only minimal spastic paraparesis. The electrophysiological examination including EMG and SEP suggested the pathological process could involve not only lateral column, but also posterior column and anterior horn. Slight but generalized spinal cord atrophy was demonstrated on metrizamide CT myelography. The muscle biopsy performed from left gastrocnemius in case 2, confirmed neurogenic changes. Although the association of retinal degeneration, cataracta, mental retardation, pes cavus or even generalized amyotrophy has been reported in familial spastic paraparesis, only limited cases are available, dealing with the amyotrophy of limbs. As far the cases with amyotrophy localized to the hands are concerned, it is absolutely rare and only the cases reported by Silver could be regarded as similar or same clinical entities to our cases.

Adolescent↗

Southern blot analysis of Bcr, N-ras, H-ras, c-myc and myb proto-oncogenes in blast crisis of chronic myelogenous leukemia.

Proto-oncogenes were studied by Southern blotting in 12 patients with chronic myelogenous leukemia in blast crisis (CML). Cytogenetically, all cases had Philadelphia (Ph1) chromosome and 4 had additional chromosomal abnormalities including +8, +19, i(17q), double Ph1. The bcr gene was rearranged in all cases and the region of breakage points were located in the 5.8 kb Bgl II-Bam HI fragment of bcr. In a case with double Ph1 the breakage points of bcr were thought to be different from each other. We analyzed other proto-oncogenes (N-ras, H-ras, c-myc and myb) by Southern blotting, but did not find any abnormalities.

Adult↗

Malignant histiocytosis with rearrangement of the heavy chain gene and evidence of monocyte-macrophage lineage.

A unique case of malignant histiocytosis (MH) is reported. Its origin from the monocyte-macrophage system was indicated by expression of highly specific myeloid cell markers (My4, MCS2, and cytoplasmic lysozyme), diffuse activity of acid phosphatase and NaF-sensitive alpha-naphthyl acetate esterase, lack of immunologic markers specific for other cell lineages, and germ line configuration of the immunoglobulin light chain gene and the T-cell receptor beta-chain gene. Its neoplastic nature was suggested by the single rearranged band of the immunoglobulin heavy chain gene.

Adult↗

Establishment of a peripheral T-cell lymphoma cell line showing amplification of the c-myc oncogene.

A new T-cell lymphoma cell line, designated T34, was established from freshly isolated lymph node tumor cells of a patient with non-Hodgkin's diffuse large cell lymphoma. The T34 cells, as well as the parental lymphoma cells, showed mature helper/inducer immunophenotypes in that they formed spontaneous sheep erythrocyte rosettes and reacted with OKT-3 and OKT-4 monoclonal antibodies. They were negative for OKT-6, OKT-8, terminal deoxynucleotidyl transferase, WT-1, and HLA-DR antigens. Molecular analysis revealed that the T34 cells contained 8- to 16-fold amplified c-myc DNA. The same genetic change was observed in parental lymphoma cells, indicating that the c-myc amplification had occurred in vivo. There was no gross rearrangement of the c-myc DNA. The c-myc gene of the T34 cell line was actively transcribed into normal-sized c-myc mRNA. Cytogenetic analysis showed that both the T34 and the parental lymphoma cells had a near-triploid karyotype with multiple structural chromosome changes. The terminal end of the long arm of chromosome No. 8, the chromosomal locus of single-copy c-myc, was elongated (8q+ chromosome), perhaps reflecting the site of c-myc amplification. These data suggested that amplification of the c-myc oncogene played some role in progression and proliferation of this peripheral T-cell neoplasm.

Aged↗