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Biomedical subjects

Y Okubo

Publications and source records attributed to Y Okubo.

At least 163 records · Page 9Linked to original sources
PubMed1997

The RHD gene is highly detectable in RhD-negative Japanese donors.

Recent molecular studies on the Rh blood group system have shown that the Rh locus of each haploid RhD-positive chromosome is composed of two structural genes: RHD and RHCE, whereas the locus is made of a single gene (RHCE) on each haploid RhD-negative chromosome. We analyzed the presence or absence of the RHD gene in 130 Japanese RhD-negative donors using the PCR method. The RhD-negative phenotypes consisted of 34 ccEe, 27 ccee, 17 ccEE, 26 Ccee, 19 CcEe, 1 CcEE, and 6 CCee. Among them, 36 (27.7%) donors demonstrated the presence of the RHD gene. Others showed gross or partial deletions of the RHD gene. These results were confirmed by Southern blot analysis. Additionally, the RHD gene detected in the RhD-negative donors seemed to be intact through sequencing of the RhD polypeptide cDNA and the promoter region of RHD gene. The phenotypes of these donors with the RHD gene were CC or Cc, but not cc. It suggested that there is some relationship between the RHD gene and the RhC phenotypes in RhD-negative individuals. In Caucasian RhD-negative individuals, the RHD gene has not been found outside of the report of Hyland et al. (Hyland, C.A., L.C. Wolter, and A. Saul. 1994. Blood. 84:321-324). The discrepant data on the RHD gene in RhD-negative donors between Japanese and Caucasians appear to be derived from the difference of the frequency of RhD-negative and RhC-positive phenotypes. Careful attention is necessary for clinicians in applying RhD genotyping to clinical medicine.

Base Sequence↗
PubMed1997

Wide variety of point mutations in the H gene of Bombay and para-Bombay individuals that inactivate H enzyme.

The H genes, encoding an alpha1,2fucosyltransferase, which defines blood groups with the H structure, of four Bombay and 13 para-Bombay Japanese individuals were analyzed for mutations. Four Bombay individuals were homologous for the same null H allele, which is inactivated by a single nonsense mutation at position 695 from G to A (G695A), resulting in termination of H gene translation. The allele inactivated by the G695A was designated h1. The other 13 para-Bombay individuals possessed a trace amount of H antigens on erythrocytes regardless of their secretor status. Sequence analysis of their H genes showed four additional inactivated H gene alleles, h2, h3, h4, and h5. The h2 allele possesed a single base deletion at position 990 G (990-del). The h3 and h4 alleles possessed a single missense mutation, T721C, which changes Tyr 241 to His, and G442T, which changes Asp148 to Tyr, respectively. The h5 allele possessed two missense mutations, T460C (Tyr154to His) and G1042A (Glu348to Lys). The h2, h3, h4, and h5 enzymes directed by these alleles were not fully inactivated by the deletion and the missense mutations expressing some residual enzyme activity resulting in synthesis of H antigen on erythrocytes. Thirteen para-Bombay individuals whose erythrocytes retained a trace amount of H antigen were determined to be heterozygous or homozygous for at least one of h2, h3, h4, or h5 alleles. This clarified that the levels (null to trace amount) of H antigen expression on erythrocytes of Bombay and para-Bombay individuals are determined solely by H enzyme activity. These mutations found in the Japanese H alleles differ from a nonsense mutation found in the Indonesian population. To determine the roles of the H, Se, and Le genes in the expression of H antigen in secretions and Lewis blood group antigen on erythrocytes, the Lewis and secretor genes were also examined in these Bombay and para-Bombay individuals. The Lewis blood group phenotype, Le(alpha- b+), was determined by the combinatorial activity of two fucosyltransferases, the Lewis enzyme and the secretor enzyme, and the secretor status was solely determined by the secretor enzyme activity, not by H enzyme activity. Bombay individuals were confirmed to be homozygous for the inactivated H and Se genes. As expected from the very low frequency of Bombay and para-Bombay individuals in the population, ie, approximately one in two or 300,000, the H gene mutations were found to be very variable, unlike the cases of the point mutations in the other glycosyltransferase genes; the ABO genes, the Lewis gene, and the secretor gene.

Adenine↗
PubMed1997

Decreased prefrontal dopamine D1 receptors in schizophrenia revealed by PET.

Schizophrenia is believed to involve altered activation of dopamine receptors, and support for this hypothesis comes from the antipsychotic effect of antagonists of the dopamine D2 receptor (D2R). D2R is expressed most highly in the striatum, but most of the recent positron emission tomography (PET) studies have failed to show any change in D2R densities in the striatum of schizophrenics, raising the possibility that other receptors may also be involved. In particular, the dopamine D1 receptor (D1R), which is highly expressed in the prefrontal cortex, has been implicated in the control of working memory, and working memory dysfunction is a prominent feature of schizophrenia. We have therefore used PET to examine the distribution of D1R and D2R in brains of drug-naive or drug-free schizophrenic patients. Although no differences were observed in the striatum relative to control subjects, binding of radioligand to D1R was reduced in the prefrontal cortex of schizophrenics. This reduction was related to the severity of the negative symptoms (for instance, emotional withdrawal) and to poor performance in the Wisconsin Card Sorting Test. We propose that dysfunction of D1R signalling in the prefrontal cortex may contribute to the negative symptoms and cognitive deficits seen in schizophrenia.

Adult↗
PubMed1997

The Oka blood group antigen is a marker for the M6 leukocyte activation antigen, the human homolog of OX-47 antigen, basigin and neurothelin, an immunoglobulin superfamily molecule that is widely expressed in human cells and tissues.

The high-frequency blood group antigen Ok(a) is carried on a red cell membrane glycoprotein (gp) of 35-69 kDa that is widely distributed on malignant cells of different origins. Immunostaining of hemopoietic cells and a range of normal human tissues demonstrated a wide distribution of the Ok(a) gp that appears to be nonlineage-restricted, although certain tissues show differentiation-related expression. Ok(a) gp was purified from red cell membranes by immunoaffinity chromatography using mAb A103 and amino acid sequence analysis was performed. The N-terminal 30 amino acids are identical to the predicted sequence of M6 leukocyte activation antigen (M6), a member of the Ig superfamily (IgSF) with two IgSF domains. There are homologs in rat (MRC OX-47 or CE9), in mouse (basigin or gp42), and in chicken (HT7 or neurothelin). The molecular basis of the Ok(a) mutation was established by sequencing M6 cDNA derived from normal and Ok(a-) EBV-transformed B cell lines. A point mutation in the translated portion of M6 cDNA, G331AG-->AAG gives rise to a predicted E92-->K amino acid change in the first Ig-like domain of the Ok(a-) form of the protein. Transfection of mouse NS-0 cells with normal or Ok(a-) cDNA confirmed the identity of the protein and only the Ok(a-) transfectants failed to react with monoclonal anti-Ok(a) Ab.

ABO Blood-Group System↗
PubMed1997

Distribution of ABO genotypes and allele frequencies in a Korean population.

The genotypes of the ABO blood group system were investigated in Korean living in Kangwon-Do area by PCR-RFLP analysis of the seven polymorphic nucleotide positions 261, 467, 526, 646, 703, 796 and 803 of the cDNA from A1 transferase. In 253 unrelated Korean individuals, 15 genotypes were found and the allele frequencies of A(Pro), A(Leu), B, O(T) and O(A) were 0.022, 0.209, 0.209, 0.360 and 0.200, respectively, with no deviation from Hardy-Weinberg expectations (chi 2 = 2.145, d.f. = 6, 0.90 < p < 0.95). As for the distribution of allele frequencies, a significant difference was noticed between the Korean and a Japanese (chi 2 = 30.87, d.f. = 4, p < 0.001) and a German (chi 2 = 127.76, d.f. = 4, p < 0.001) populations.

ABO Blood-Group System↗
PubMed1997

Prevention of graft coronary arteriosclerosis by antisense cdk2 kinase oligonucleotide.

Graft coronary arteriosclerosis, which limits the long-term survival of allograft recipients, is characterized by diffuse intimal thickening composed of proliferative smooth muscle cells. We observed that messenger RNA of the cell cycle regulatory enzyme cyclin-dependent kinase (cdk) 2 kinase, which mediates smooth muscle cell proliferation, was elevated in the thickened intima of coronary arteries of murine heterotopic cardiac allografts. We studied the effects of antisense phosphorothioate oligodeoxynucleotide (ODN) against this enzyme using gene transfer mediated by a hemagglutinating virus of Japan (HVJ)-liposome complex intraluminally delivered to inhibit the intimal hyperplasia. At 30 days after transplantation, antisense cdk2 kinase ODN treatment had dramatically inhibited neointimal formation in the allografts. Expression of vascular cell adhesion molecule-1 was also suppressed by antisense cdk2 kinase. However, these effects were not observed in the sense or scrambled ODN-treated allografts. Thus, an intraluminal administration of antisense ODN directed to a specific cell cycle regulatory gene can inhibit neointimal formation after cardiac transplantation.

Animals↗
PubMed1997

Flow cytometric detection of cytomegalovirus antigen in peripheral blood cells after bone marrow transplantation.

Cytomegalovirus (CMV) immediate-early (IE) antigen within the nucleus of cells was detected by flow cytometry in peripheral blood obtained from five bone marrow transplant recipients. In patients with an unexplained fever, CMV antigens were detected in monocytes or lymphocytes. On the other hand, in patients with CMV pneumonia, CMV antigens were detected in polymorphonuclear leucocytes (PMNLs). We suggest that the detection of CMV antigen in monocytes or lymphocytes may be related to CMV activation or reactivation, and the positive results in PMNLs indicate that the patient has a CMV-associated disease (CMV pneumonia). Our method may be useful in monitoring CMV activation or reactivation, and analysing the mechanisms of CMV infection.

Antigens, Viral↗
PubMed1997

Intercellular adhesion molecule-1 on eosinophils is involved in eosinophil protein X release induced by cytokines.

Recent evidence suggests that adhesion molecules play important roles in eosinophil functions such as degranulation and superoxide anion production. CD11b/CD18 (Mac-1) and CD49d/CD29 (VLA-4) are involved in eosinophil-endothelial adhesion through their counterligands, intercellular adhesion molecule-1 (ICAM-1; CD54) and vascular cell adhesion molecule-1 (VCAM-1), respectively. CD54 is also induced on eosinophils by cytokine stimulation. We hypothesized that CD54 on human eosinophils may participate in eosinophil degranulation. CD54 was induced on eosinophils by a combination of human recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) and human recombinant tumour necrosis factor-alpha (rTNF-alpha) within 2 hr of incubation, as determined by flow cytometric analysis. Recombinant GM-CSF alone induced a slight but significant CD54 expression on eosinophils. Release of eosinophil protein X, an indicator of eosinophil degranulation, was induced by rGM-CSF and this effect was synergistically enhanced by adding rTNF-alpha. To determine the role of newly expressed CD54 in eosinophil degranulation, a blocking assay was performed using monoclonal antibody (mAb) against CD54 and CD18. Anti-CD18 mAb and anti-CD54 mAb markedly inhibited eosinophil degranulation induced by rGM-CSF or a combination of rGM-CSF and rTNF-alpha. On the other hand, anti-CD54 mAb had little effect on rGM-CSF- or rGM-CSF/rTNF-alpha-induced adhesion of eosinophils, whereas anti-CD18 mAb significantly inhibited eosinophil adhesion. These results indicate that CD54 on eosinophils plays an important role in the eosinophil degranulation and that eosinophils are capable of interacting with other beta 2 integrin-positive cells.

Antibodies, Monoclonal↗
PubMed1997

Induction of the 2B9 antigen/dipeptidyl peptidase IV/CD26 on human natural killer cells by IL-2, IL-12 or IL-15.

Activation of human natural killer (NK) cells involves sequential events including cytokine production and induction of cell surface molecules, resulting in the enhancement of cytolytic activity. To delineate the activation process of NK cells, we generated murine monoclonal antibodies (mAbs) against YT, a human large granular lymphocyte/natural killer (LGL/NK) cell line. Among the mAbs reactive with YT cells, one mAb, termed 2B9, was noted because of the lack of reactivity with most of the human T- and B-cell lines tested. In fresh peripheral blood mononuclear cells (PBMC), however, the majority of cells expressing this antigen (Ag) were T cells but not CD16+ nor CD56+ NK cells. Since YT cells showed an activated phenotype expressing interleukin-2 (IL-2) receptor alpha chain, we examined whether 2B9 Ag could be induced on normal human peripheral blood NK cells by cytokines known to activate NK cells. The 2B9 Ag was induced on NK cells by IL-2, IL-12 or IL-15 while no induction was observed by interferon-gamma (IFN-gamma). Biochemical analysis showed that anti-2B9 mAb recognized a 115 kDa molecule in YT cells. A cDNA clone encoding the 2B9 Ag was isolated from a cDNA expression library of YT cells and its sequence was identical to CD26 cDNA although it was not of full length. Transient expression of the 2B9 cDNA on COS-7 cells revealed that this cDNA encodes the antigenic epitope(s) recognized by anti-2B9 mAb as well as Ta1, an anti-CD26 mAb. These results showed that the 2B9 Ag is identical to CD26, and demonstrated that CD26 is an activation antigen on CD16+ CD56+ NK cells inducible by IL-2, IL-12 or IL-15.

Antibodies, Monoclonal↗
PubMed1997

Further analysis of Del (D-elute) using polymerase chain reaction (PCR) with RHD gene-specific primers.

Del (D-elute) in the Rh blood group system is a variant with very weak D antigen and no agglutination is found by the indirect antiglobulin test. This variant is characterized by the presence of anti-D eluate obtained after an adsorption-elution test using anti-D antibodies. We studied here the molecular genetic status of Del by using polymerase chain reaction with sequence-specific primers (PCR-SSP). We screened 306 serologically apparent D-negative Japanese donors comprising 102 Del types for exons 7, 4 and 10 of the RHD gene. No PCR product was found in all 204 non-Del samples from the D-seronegative donors. However, PCR products were found in all 102 Del samples and all 70 D-seropositive samples tested by the three PCR methods for exons 7, 4 and 10 analysis. Del was found with CCee, CcEe and Ccee, but not with CCEe, CcEE, ccEE, ccEe or ccee phenotype. The incidences of Del in the samples with the serological phenotypes CCee, CcEe and Ccee were 80.0% (4/5), 68.2% (45/66) and 61.6% (53/86), respectively. The results provide evidence that Del samples have exons 4, 7 and 10 of an RHD gene present in some form. This is consistent with the evidence that D antigen is present on the cells although only detected by antibody adsorption and elution. The PCR-SSP method in the present study is useful to confirm Del among serologically apparent D-negative samples.

Asian People↗
PubMed1997

DBT: a partial D phenotype associated with the low-incidence antigen Rh32.

Eight probands are described with a D phenotype in which a partial D antigen is associated with Rh32 antigen; three of these probands were investigated because of the anti-D in their serum. The partial D lacks epD1-epD5 and epD9 and some epD6/7 and only expresses epD8 and other parts of epD6/7. The strength of the partial D antigen varies between unrelated DBT individuals. The Rh32 antigen of the DBT cells is weaker than that of D(C)(e) cells. Tests on DBT, DFR and R0Har cells with anti-epD6/7 split these monoclonal anti-D into eight patterns of reaction. A new pattern of reactions was observed, presaging a new epitope, but this was not numbered.

Antibodies, Monoclonal↗
PubMed1997

The effect of epidural saline injection on analgesic level during combined spinal and epidural anesthesia assessed clinically and myelographically.

UNLABELLED: An epidural injection of physiological saline solution after spinal anesthesia may produce a higher level of analgesia than spinal anesthesia alone because of a volume effect. The purpose of this study was to clarify the volume effect caused by epidural injection of saline after spinal anesthesia. Twenty patients undergoing combined spinal and epidural anesthesia for elective surgery whose analgesic levels did not reach the surgical regions 10 min after spinal anesthesia at the L4-5 interspace were randomly assigned to two groups. The control group (n = 10) received no epidural saline injection. The saline group (n = 10) received 10 mL of saline through an epidural catheter at the L2-3 or L3-4 interspace 10 min after spinal anesthesia. In the saline group, the levels of analgesia 15 and 20 min after spinal anesthesia were significantly higher than those in the control group (P < 0.05). Next, we examined the volume effect of epidural injection of saline with myelography using two adult volunteers. In both volunteers, the upper level of the contrast medium, which was injected in the lumbar subarachnoid space, began to increase concurrently with lumbar epidural injection of saline, reaching from L3 to L1 and from L2 to T12. The diameter of the subarachnoid space diminished to less than 25% after injection of saline. We conclude that lumbar epidural injection of saline increases the analgesic level 10 min after spinal anesthesia, probably because of a volume effect. IMPLICATIONS: In this study, using surgical patients and volunteers, we determined that a lumbar epidural injection of physiological saline solution 10 min after spinal anesthesia produces a higher analgesic level than spinal anesthesia alone because of a volume effect.

Adult↗
PubMed1997

Relationship between levels of soluble interleukin-2 receptors and the types and activity of vitiligo.

Levels of serum-soluble interleukin-2 receptors (serum sIL-2R) are thought to indicate the activation of immunocompetent cells, mainly lymphocytes. Elevated levels of serum sIL-2R have been observed in various infectious and autoimmune diseases and also after organ transplantation. It has been hypothesized that autoimmune mechanisms are involved in the pathogenesis of vitiligo. Therefore, we studied serum sIL-2R levels in relation to disease types and activity of vitiligo. We used sera separated from venous blood samples from 12 patients with dermatomally distributed type B vitiligo, 17 patients with non-dermatomally distributed type A vitiligo during the active stage, 9 patients with type A vitiligo during the inactive stage, and 12 normal control subjects. Serum sIL-2R levels were similar in type B vitiligo patients and the controls but were significantly elevated in patients with active type A vitiligo compared with controls and inactive type A vitiligo patients. It is suggested that the immune system is activated in patients with type A vitiligo during the active stage and that autoimmune mechanisms may play a role only in type A vitiligo.

Autoimmunity↗
PubMed1997

Quantitative EEG correlates of normal aging in the elderly.

To clarify the effect of normal aging on the EEG in the elderly, relative EEG power and coherence were studied in 68 elderly subjects (age range 61-90 years) as well as in 20 young subjects (age range 23-38 years). Relative beta power was significantly higher in the elderly subjects, while no significant differences were seen among the elderly groups. Therefore it may be assumed that EEG power in the centrooccipital region among the normal elderly remains almost unchanged. Also, age had no effect on interhemispheric coherence. However, intrahemispheric coherence was found to decrease with age in all bands almost linearly. Thus, intrahemispheric coherence is a more sensitive indicator of normal aging than relative power.

Adult↗
PubMed1997

Interleukin-13 but not interleukin-4 prolongs eosinophil survival and induces eosinophil chemotaxis.

The effects of recombinant human (rh) interleukin (IL)-4 or rhIL-13 on survival, and chemotactic activity of human eosinophils were examined. Only rhIL-13 prolonged eosinophil survival in a dose-dependent manner above 3 ng/ml. Eosinophil survival induced by rhIL-13 was inhibited by monoclonal antibodies (mAbs) against IL-3 (p < 0.01) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (p < 0.05), suggesting that rhIL-13 induced IL-3 and GM-CSF production from eosinophils and an autocrine mechanism is responsible for the eosinophil survival. The effects of rhIL-13 on eosinophil chemotactic activity were also examined. rhIL-13 showed chemotactic activity for eosinophils in a dose-dependent manner. Checkerboard analysis revealed that eosinophil migration was dependent on the concentration gradient, confirming that rhIL-13 is a chemotactic factor. rhIL-4 showed no effects. IL-13 may play an important role in the survival and recruitment of eosinophils in allergic diseases.

Cell Degranulation↗