Biomedical subjects

M Mayumi

Publications and source records attributed to M Mayumi.

At least 235 records · Page 13Linked to original sources

PubMed1987

Site-directed mutagenesis of hepatitis B surface antigen sequence at codon 160 from arginine to lysine for conversion of subtypic determinant from r to w.

Site-directed mutagenesis from G to A was induced at nucleotide 479 in the S gene of hepatitis B virus DNA, cloned from an individual carrying the surface antigen of subtype ayr. HepG2 cells were transfected with the plasmid DNA containing the mutant. They produced surface antigen of subtype ayw, unlike HepG2 cells harboring the parent viral DNA that produced surface antigen of subtype ayr. These results indicate that a point mutation from G to A at nucleotide 479 in the S gene, changing codon 160 for arginine to that for lysine, can convert the subtypic determinant of hepatitis B surface antigen from r to its allelic determinant w.

Amino Acid Sequence↗

PubMed1987

Establishment of a common acute lymphoblastic leukemia cell line (LC4-1) and effects of phorbol myristate acetate (PMA) on the surface antigen expression of the cell line.

A common acute lymphoblastic leukemia (ALL) cell line, designated LC4-1, was established from peripheral blood mononuclear cells of a patient with acute non-T-cell ALL. LC4-1 cells were characteristically positive for Ia, B4, and common ALL antigens (CALLA), but negative for B2, Tac, T3, T4, T8, T11, and M1 antigens and E-rosette formation. Approximately 30% of LC4-1 cells expressed detectable amounts of B1 antigens. LC4-1 cells expressed neither Epstein-Barr-virus-associated nuclear antigen (EBNA), cytoplasmic immunoglobulins (cIg) nor surface immunoglobulins (sIg). Gene rearrangements had already occurred in LC4-1 in the D-J region of immunoglobulin heavy chain genes, but not in T-cell receptor (beta-chain) genes, suggesting that LC4-1 is a progenitor cell line of B-cell lineage earlier than pre-B-cells. The expression of cell surface antigens of LC4-1 was changed by treatment with 4-phorbol 12-myristate 13-acetate (PMA) (0.1 ng/ml) for 2 days. Before treatment with PMA, about 98% of LC4-1 cells were positive for B4, CALLA, and Ia. However, following treatment they lost CALLA expression without any change in expression of Ia and B4. There was no change in B1-positive population. The change in surface antigens on LC4-1 cells seems to be due to differentiation induced in the cells by PMA. These results support the hypothesis that CALLA is a differentiation antigen and suggest one possible differentiation pathway for pre-B-cells.

Antibodies, Monoclonal↗

PubMed1987

Colony-stimulating factor and leukemia cell-growth factor produced by a murine endothelial cell line, MKM-O.

A murine cultured cell line (MKM-O) was established from a tumor of a BALB/C (nu/nu) mouse that had been subcutaneously inoculated with human hepatoma tissue fragments in the same location. The MKM-O cell line was proven to be of endothelial origin by morphological examinations and positive staining with fluorescein-labeled antibody against factor VIII antigen. MKM-O cells grown in vitro produced a colony-stimulating factor (CSF) and a leukemia cell-growth factor (LC-GF). CSF from MKM-O acted on both human and murine bone marrow-derived granulocytes and macrophage colony-forming units (CFU-GM). The activity of LC-GF on human leukemia cell lines (HL-60, HSB-2, CEM, DAUDI and K562) was demonstrated both in conditioned medium (CM) of MKM-O and of rat vascular endothelial cells. The CM of MKM-O also demonstrated a limited growth promoting activity against the mononuclear cells from human cord blood and improved their survival, suggesting that endothelial cells play an important role in the proliferation and differentiation of blood cells.

Animals↗

PubMed1987

Point mutation in the S gene of hepatitis B virus for a d/y or w/r subtypic change in two blood donors carrying a surface antigen of compound subtype adyr or adwr.

Genomes of hepatitis B virus (HBV) were cloned from the plasma of a blood donor who carried subviral particles of three distinct subtypes in the following proportions: adr, 25%; ayr, 63%; and adyr, 12%. HBV DNA clones were classified into two groups based on a difference at only one nucleotide in the S gene. Two clones had A as nucleotide 365 that formed part of the codon for lysine as amino acid residue 122 and produced a surface antigen of subtype adr in transfected NIH 3T3 cells. The remaining four clones had G determining the codon for arginine and produced a surface antigen of subtype ayr in transfected cells. Similarly, HBV genomes were cloned from the plasma of an individual who carried subviral particles of subtypes adr (71%) and adwr (29%). Two clones had T and A as nucleotides 476 and 479, respectively. The other seven clones had C and G as the respective nucleotides. Based on a comparison with previously reported HBV genomes of various subtypes, the mutation of nucleotide 479, forming part of the codon for lysine or arginine as amino acid residue 160, was deduced to determine the w or r subtype, respectively. When NIH 3T3 cells were transfected separately with the genome of subtype adw or adr, derived from plasma containing a surface antigen of subtype adwr, and then cocultured, they produced subviral particles of either subtype adw or adr. When cells were transfected with the genomes of subtypes adw and adr simultaneously, however, subviral particles were produced that possessed w and r determinants on the selfsame particles. These results attributed the d/y or w/r subtypic change to a point mutation in the S gene and favored coinfection of hepatocytes with an HBV genome and its mutant as the mechanism of compound subtypes.

Base Sequence↗

PubMed1987

Free and integrated forms of hepatitis B virus DNA in human hepatocellular carcinoma cells (PLC/342) propagated in nude mice.

Primary hepatocellular carcinoma cells (PLC/342) propagated in nude mice produce hepatitis B surface antigen of subtype adr, as well as core particles containing viral DNA and DNA polymerase. Free and integrated forms of hepatitis B virus (HBV) DNA in the tumor were isolated by molecular cloning, and their nucleotide sequences were determined. Both of the two representative clones of free HBV DNA had the same genomic length (3,158 base pairs) and had two stop codons as well as two deletions in the envelope gene. None of the seven distinct clones of integrated HBV DNA possessed the entire viral genome. The integrated clone sequences had deletions and rearrangements, and only two clones possessed the envelope gene including the promoter and enhancer sequences. The C gene, which codes for core protein, was preserved in the two free clones and one of the integrated clones. The P gene, which codes for DNA polymerase, had deletions at two positions of 21 and 36 base pairs in both free clones, but was carried in toto by one of the integrated clones. The nucleotide sequences of the S genes of two free and four integrated clones, as well as their two inverted repeats, were compared. All of the eight sequences of the S gene possessed two nucleotide substitutions in common that were not displayed by any of the reported HBV genomes. The sequences differed from one another by only 1.2%. They differed, however, from 11 reported HBV genomes of subtype adr by 2.4%, from an ayr genome by 1.9%, from 2 adw genomes by 6.9%, and from 2 ayw genomes by 5.9%. These results indicate that all free and integrated HBV DNA species in the PLC/342 tumor cell evolved from a common progenitor. The free HBV DNA underwent nucleotide substitutions during several integration events, resulting in integrated HBV DNA copies that were similar in sequence but distinct from the reported HBV genomes.

Animals↗

PubMed1987

Low burst promoting activity production by phytohemagglutinin-stimulated mononuclear cells of cord blood.

Burst-promoting activity (BPA) produced by phytohemagglutinin(PHA)-stimulated cord blood mononuclear cells (MNC) was examined using the two-stage cell culture assays. Burst-promoting activity was measured as the increase in the number of early erythroid progenitor cells in 2-day incubation of peripheral blood MNC with or without the conditioned medium of PHA-stimulated MNC (PHA-LCM). Burst-promoting activity in PHA-LCM of cord blood was significantly lower than that of adult blood (37 +/- 13 versus 105 +/- 19%, mean +/- SD, p less than 0.01). No elevation of inhibitors to the erythroid colony growth was noted in PHA-LCM of cord blood. In contrary, the response of cord blood MNC to PHA was similar to that of adult blood MNC, as determined by colony-stimulating activity production and cell proliferation. These results showed that burst-promoting activity production by PHA-stimulated MNC of cord blood was lower than that of adult blood.

Cells, Cultured↗

PubMed1987

Short-term prednisolone for inducing seroconversion from hepatitis B e antigen to antibody along with clinical improvement in patients with chronic active hepatitis type B.

Short-term prednisolone therapy was instituted on 27 patients with chronic active hepatitis (CAH) type B, in an attempt to induce seroconversion from hepatitis B e antigen (HBeAg) to the corresponding antibody (anti-HBe). Patients with CAH received a four-week regimen of prednisolone with daily dosage tapering from 40 to 10 mg (total 700 mg). Within one year after the withdrawal of prednisolone, 19 (70%) lost HBeAg and 11 of them (41% of the total) developed anti-HBe, at rates significantly higher than 3 (12%) and 1 (4%) who spontaneously showed respective serological changes among 26 matched controls during one year (p less than 0.001). Within two years after the withdrawal, 21 (78%) lost HBeAg and 19 (70%) developed anti-HBe, in contrast to 6 (23%) and 2 (8%) of controls who showed respective changes during that period (p less than 0.001). Seroconversion to anti-HBe was invariably accompanied by clinical and biochemical improvements along with loss of DNA polymerase from circulation. Elevation in transaminase levels, reflecting the rebound of steroid withdrawal, always heralded and appeared to be required for the seroconversion, but serious aggravation of hepatitis was not encountered in any of the patients.

Adult↗

PubMed1987

Regulation of IgE receptor expression on human peripheral blood lymphocytes by lymphocytosis promoting factor (LPF), lectins and dexamethasone.

Using a monoclonal anti-human Fc epsilon R antibody (H107), we found that lymphocytosis promoting factor (LPF), phytohaemagglutinin (PHA-P) and Concanavalin A (Con A) could induce Fc epsilon R, detected by immunofluorescence study, on normal human peripheral blood lymphocytes without IgE. The number of Fc epsilon R bearing lymphocytes was increased by stimulation with 3, 10 and 10 micrograms/ml of LPF, PHA-P and Con A, respectively, from 6.0 +/- 3.0/1000 cells to 26.0 +/- 7.9, 54.0 +/- 6.7 and 24.8 +/- 7.1/1000 cells, respectively. Although the induction of Fc epsilon R occurred neither in the separated T-enriched fraction (TEF) nor the T-depleted fraction (TDF), it recovered when the two fractions were mixed. The cell free supernatants from TEF stimulated with LPF or PHA-P could increase Fc epsilon R(+) cells in TDF, whereas those from TDF failed to increase them in TEF. The results suggest that the induction of Fc epsilon R occurs mainly on B lymphocytes by the soluble factor(s) formed by T cells stimulated with LPF or PHA-P. The induction of Fc epsilon R by stimulants was completely inhibited by 10(-6) M dexamethasone. It was demonstrated that the effects of dexamethasone on lymphocytes were dual: one was on B cells to inhibit responsive increases of Fc epsilon R, and the other was on T cells to suppress the formation of the soluble factor(s) which induced Fc epsilon R on B cells.

Dexamethasone↗

PubMed1987

Analysis with antiidiotype antibody of a patient with chronic lymphocytic leukemia and a large cell lymphoma (Richter's syndrome).

A murine monoclonal antibody made against an idiotypic determinant (Id) of surface IgM/IgD lambda molecules on chronic lymphocytic leukemia (CLL) cells of a 71-year-old woman was used for clonal analysis by two-color immunofluorescence. The anti-Id antibody identified IgM+/IgD+/lambda+ B cells as the predominant cell type of her CLL clone. In addition, substantial proportions of the IgG and IgA B cells and most of the IgM plasma cells in her bone marrow and blood were Id+. Six years after diagnosis, the patient died of respiratory failure due to infiltration of lungs by malignant cells. Autopsy revealed a dramatic change in the tumor cell morphology. The lungs, hilar nodes, and liver were infiltrated by a diffuse large cell lymphoma admixed with the leukemic cells. By immunohistologic staining these anaplastic lymphoma cells were IgM+/IgD-/lambda+ B cells expressing the same Id noted earlier on the CLL cells. The immunoglobulin gene rearrangement pattern on Southern blot analysis was also the same in leukemic blood cells and in the tissues involved by the lymphoma. Thus, the combination of antiidiotype and immunoglobulin gene analyses in this patient with Richter's syndrome revealed that a CLL clone, seemingly "frozen" in differentiation, was actually undergoing isotype switching, differentiation into plasma cells, and evolution into a rapidly growing and fetal lymphoma.

Aged↗

PubMed1987

[Clinical studies of flomoxef in the field of pediatrics].

Flomoxef (FMOX, 6315-S), a newly synthesized antibiotic which belongs to the oxacephem group, was clinically evaluated for its efficacy and safety in 17 patients with ages ranging from 1 month to 9 year-8-month who had bacterial infections. The results obtained were summarized as follows. 1. A pharmacokinetic study following 20 mg/kg FMOX administration by intravenous bolus injection showed that the half-life of FMOX (beta phase) was 39.8 minutes and the urinary excretion of FMOX in the first 6 hours was 76.5%. 2. FMOX was administered to 3 patients with pneumonia, 8 patients with bronchopneumonia, 2 patients with tonsillitis, 2 patients with pyelonephritis, one patient each with cervical lymphadenitis, and pustulosis associated with severe varicella at daily dosage levels of 61.9 approximately 87.2 mg/kg, divided into 3 or 4 administrations by intravenous bolus injection or by 30 minutes drip infusion. The clinical results of these 17 patients were as follows; excellent: 14 patients, good: 2 patients, poor: 1 patient. The efficacy rate was 94.1%. 3. No clinical adverse reaction was observed in any of the 17 patients. Neutropenia, eosinophilia, a slight elevation of GPT and slight elevations of GOT & GPT were observed in 1, 1, 1, and 2 patients, respectively. No abnormality in coagulation system was observed in any of 10 evaluable patients. 4. MICs of FMOX against 13 strains isolated from patients were as follows. MIC against 2 out of 3 strains of Streptococcus pneumoniae was 0.20 micrograms/ml and that of the remaining 1 strain was 0.39 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1987

Defective mutants of hepatitis B virus in the circulation of symptom-free carriers.

A total of 75 clones of hepatitis B virus (HBV) DNA were isolated from the plasma of 4 symptom-free carriers. Each set of clones from a carrier all possessed at least one complete genome, for which the entire nucleotide sequence was determined. A deletion of nucleotide sequence, spanning from 13 to 1071 base pairs, was detected in 17 clones (23%). As many as 16 of them had a deletion in the C gene, with or without the involvement of the P and X genes. The remaining one clone had a deletion restricted to the pre-S region. Accordingly, these defective mutants could not replicate themselves without help from complete HBV co-infecting the same hepatocyte. Defective mutants would have developed during the replication of HBV by reverse transcription of an RNA intermediate, and provide another evidence for a close similarity of HBV with retroviruses.

Chromosome Deletion↗

PubMed1987

Genomic heterogeneity of hepatitis B virus in a 54-year-old woman who contracted the infection through materno-fetal transmission.

From the plasma of a 54-year-old woman, who acquired the persistent carrier state of hepatitis B virus through materno-fetal transmission, 49 clones of viral genomes were propagated. They did not reveal any differences in the size and number of cleavage products with any of 11 restriction endonucleases. Randomly selected 5 clones were classified into 3 groups by the variation at 4 positions in the nucleotide sequence of the envelope and core genes. The complete nucleotide sequences were determined for 3 of them, each representing a group, and they all had a genomic length of 3215 nucleotides. Variation was found in from 5 to 11 nucleotides. Assuming the infection with the common ancestor virus at birth, hepatitis B virus genomes in her plasma were estimated to have evolved at a rate from 1.4 to 3.2 x 10(-5) nucleotide substitutions per site per year. This value is 10(4)-fold greater than DNA genomes, 10(2)-fold less than human immunodeficiency virus but in the same order as most RNA viruses including certain retroviruses.

Base Sequence↗

PubMed1987

[Clinical evaluation of cefuzonam in children].

Cefuzonam (L-105, CZON), a new parenteral cephalosporin, was evaluated for its efficacy and safety in 22 children with bacterial infections (Table 1). The results obtained are summarized below. MICs of CZON to 26 strains of isolated organisms are shown in Table 2. MICs to all 14 strains of Haemophilus influenzae and 6 strains of Streptococcus pneumoniae were less than 0.05 microgram/ml. The MIC to 2 strains of Staphylococcus aureus was 0.39 microgram/ml and that to another was 0.78 microgram/ml. Two strains of Escherichia coli showed MICs of less than 0.05 and 0.10 microgram/ml, respectively. The MIC to 1 strain of Enterococcus faecalis was 6.25 micrograms/ml. The CZON was administered in 3 or 4 divided doses at a daily dosage ranging from 58.5 to 85.7 mg/kg by 30-minute drip infusion or intravenous injection to 22 patients (9 cases of pneumonia, 9 cases of tonsillitis, 2 cases of bronchitis, 1 case each of suppurative parotitis and acute pyelonephritis) and the following clinical results were obtained; excellent: 12 cases; good: 7 cases; fair: 3 cases. The overall efficacy rate was 86% (Table 4). Diarrhea was observed in four patients, and was resolved with or without discontinuation of the medication within a week. Anemia was noted in 2 cases. Leucopenia and neutropenia was observed in 1 case. There were a moderate rises in S-GOT and S-GPT activities in 1 patient (Table 4), and they necessitated the cessation of the CZON therapy. The S-GOT and S-GPT activities became normal after the drug treatment was stopped.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1987

Interaction between human albumin polymers and the envelope polypeptide of hepatitis B virus (P31) containing the translation product of the pre-S2 region.

Two preparations of human serum albumin (Cohn fraction V), when subjected to high-performance liquid chromatography, were found to contain albumin polymers with molecular sizes of 35 X 10(4) daltons or greater (breakthrough fraction), as well as tetramers, trimers and dimers. They bound to the envelope polypeptide of hepatitis B virus composed of translation products of the pre-S2 region and the S gene (P31), carrying the receptor for polymerized human serum albumin, with an activity increasing in parallel with the degree polymerization.

Genes↗

PubMed1986

A solid-phase enzyme immunoassay for the common and subtypic determinants of hepatitis B surface antigen with monoclonal antibodies.

Monoclonal antibodies were raised against the common (a) as well as subtypic determinants (d, y, w and r) of hepatitis B surface antigen (HBsAg). They were applied to subtyping HBsAg by sandwiching it between antibody against a fixed on a solid-phase support and antibody against one or other of d, y, w and r, linked to horseradish peroxidase. The assay was applied to evaluate antigenic specificities of the NIH and Japanese panels composed of 44 sera containing HBsAg particles of various subtypes. HBsAg particles of a hybrid subtype, adyr, were sandwiched between monoclonal antibody against d and that against y, thereby indicating that they possessed both d and y determinants on the selfsame particle. The expression of d and y determinants on hybrid HBsAg particles was much less than that on ordinary particles of adw, adr, ayw or ayr subtype.

Animals↗

PubMed1986

A radioimmunoassay that sandwiches human interleukin-2 between radiolabeled monoclonal antibody and the receptor on a hematopoietic cell line.

Two monoclonal antibodies were raised against human interleukin-2 (IL-2) produced by E. coli harboring recombinant complemental DNA. Both antibodies did not neutralize its activity, nor did they inhibit the binding of IL-2 to the receptor on target cells. Taking advantage of the ability of monoclonal antibodies to detect IL-2 that had bound to the receptor, a radioimmunoassay was developed that sandwiched IL-2 between the radiolabeled monoclonal antibody and the receptor on a hematopoietic cell line infected with human T cell leukemia virus Type I. The assay had the advantage of detecting only IL-2 with the ability to bind to the receptor, and displayed a linear dose-response relationship over concentrations ranging from 5 to 100 ng/ml.

Antibodies, Monoclonal↗

PubMed1986

Application of monoclonal antibodies to the isolation and characterization of a killer toxin secreted by Hansenula mrakii.

A strain of yeast, Hansenula mrakii, secretes a toxin that kills sensitive yeasts, such as Saccharomyces cerevisiae Monoclonal antibodies raised against the toxin had both binding and neutralizing activities. The toxin in culture media was isolated by an affinity column of monoclonal antibody. The toxin is a basic polypeptide with an isoelectric point at pH 9.1, and devoid of mannosides. It is composed of 88 amino acid residues with a molecular size of 10 721 Da. The monoclonal antibodies could be applicable to the analysis of biologically active sites on the toxin, in an attempt to synthesize chemically a small peptide with killer activity and little immunogenicity.

Amino Acid Sequence↗

PubMed1986

Selective immunoglobulin M deficiency associated with disseminated molluscum contagiosum.

A 16-year-old girl with disseminated molluscum contagiosum (MC) was found to have a very low level of serum IgM, elevated levels of IgG and IgA, and a high level of IgE. She had normal numbers of peripheral blood IgM+, IgG+ and IgA+ B-lymphocytes but their terminal differentiation into plasma cells could not be induced by pokeweed mitogen (PWM) in vitro. On the other hand, the patient's T-cells showed normal helper functions in the PWM system and normal interferon (IFN) production in vitro. However, the IgM+ B-cells can be induced to differentiate into IgM secreting cells by Epstein-Barr virus (EBV), suggesting that the genetic mechanism for synthesis of the component immunoglobulin proteins is present. T-cell functions were impaired, as shown by delayed type cutaneous hypersensitivity (DTH) and mitogen response. The data suggest that the selective IgM deficiency of the patient is due mainly to defects in B-cells at the terminal differentiation stage, but immunological abnormalities are present in both B and T-cell systems. Neutrophil functions examined were normal. MC was treated by intravenous injection of IFN without any side effects; however, no clinical improvement was achieved.

Adolescent↗