Biomedical subjects

K Miyamura

Publications and source records attributed to K Miyamura.

At least 37 records · Page 2Linked to original sources

PubMed1997

Prolonged selective neutropenia after allogeneic bone marrow transplantation: possible effect of presensitization by donor lymphocytes prior to transplant.

Selective neutropenia lasting over five months occurred in a 17-year-old adolescent male who received an allogeneic bone marrow transplantation (BMT) from an HLA-identical sibling for severe aplastic anemia. Bone marrow specimens showed maturation arrest of myeloid precursor cells despite sustained engraftment. Cytogenetic analyses revealed complete donor-type chimerism in hematopoietic cells and mixed lymphoid chimerism. The patient received a second BMT from the same donor following more intensive conditioning, including total body irradiation. Neutrophil recovery was rapid and complete donor-type hematopoietic and lymphoid chimerism was observed within three weeks of the second transplant. The present case suggests that prolonged selective neutropenia following BMT is due to residual host-derived immunity which is resistant to the standard immunosuppressive conditioning used prior to BMT for aplastic anemia.

Adolescent↗

PubMed1997

Early diagnosis of vertical HIV infection in infants by rapid detection of immune complex-dissociated HIV p24 antigen.

Conventional HIV antibody detection was problematic for diagnosis of HIV infection in young infants < 18 months of age who were born to HIV-infected mothers. The HIV p24 antigen (Ag) is mainly bound to the antibody as an immune complex which causes underdetection by conventional methods. Attempts were made to dissociate these immune complexes to release free p24 Ag for detection. The current study's objective was to evaluate the rapid assays for detection of immune complex-dissociated p24 Ag (ICD p24 Ag) for early identification of HIV-infected infants as compared to the detection of HIV RNA by polymerase chain reaction (PCR) assay. The ICD was performed by acid dissociation and heat-denatured dissociation, and then the released ICD p24 Ag were detected. Tested were 41 HIV-infected children who acquired the infection perinatally and who had positive PCR and 30 HIV noninfected children with negative PCR. The overall sensitivity of the ICD p24 Ag detection after acid- and heat-denatured dissociation in the infected children was 85.4% and 87.8%, respectively, compared to 34.2% of p24 Ag without pretreatment for dissociation of the serum samples. The specificity of nonimmune complex dissociation and both methods of immune complex dissociation test were 100%. The sensitivity of ICD-p24 Ag test using these two methods showed excellent agreement (K = 0.893). Besides the relatively high sensitivity and specificity of the ICD p24 Ag test, its advantages include simplicity, rapidity, and relatively low cost--indicating ICD p24 Ag detection as a promising method for early diagnosis of vertical HIV infection in infants.

Antibodies, Viral↗

PubMed1997

Treatment of metastatic uterine leiomyosarcoma with cisplatin, pirarubicin, and ifosfamide.

We present the unusual case of a 27-year-old Japanese woman who exhibited recurrences of metastatic tumors from uterine leiomyosarcoma after five operations. Chemotherapy with cisplatin, pirarubicin, and cyclophosphamide was ineffective. Substituting ifosfamide for cyclophosphamide, we obtained a complete response. The Gynecologic Oncology Group (GOG) in the United States has recognized the efficacy of ifosfamide and mesna in the treatment of patients with advanced or recurrent uterine sarcomas. Here we report on the efficacy of ifosfamide in addition to cisplatin and pirarubicin.

Adult↗

PubMed1997

Insulin-like growth factor-binding protein-1 in human follicular fluid: a marker for oocyte maturation.

In order to investigate the role of insulin-like growth factors (IGFs) in human ovulation, we evaluated the concentrations of IGF-binding proteins (IGFBPs) in human follicular fluid (FF). The concentrations of IGFBP-1 in the FFs of 15 women undergoing in vitro fertilization and embryo transfer were measured and related to those of 17beta-estradiol (E2), progesterone and androstenedione in the FFs. IGFBP-1 levels in the FFs were positively correlated with those of E2 and progesterone. No correlation was found between the IGFBP-1 and androstenedione levels in FFs. The concentrations of IGFBP-1 were significantly increased in the FFs which contained mature oocytes compared with those of immature oocytes, whereas IGFBP-3 in FFs tended to decrease as oocytes matured. It is suggested that IGFs may play important roles in human preovulatory processes, and that IGFBP-1 may be a valuable biochemical marker in the evaluation of oocytes.

Androstenedione↗

PubMed1996

No proof of HTLV-I/II in intravenous drug abusers with a high rate of HIV-1 infection in central Thailand.

Serum specimens of 1,074 intravenous drug abusers (IVDA) were examined for infection with HIV-1, HTLV-I and HTLV-II in central Thailand. Three hundred and sixty-two of the specimens were seropositive for HIV-1 (33.7%). The HIV-1 seropositive IVDAs exhibited increased seropositivity with age through group 40-44 and significantly decreased seropositivity over the age of 45. In contrast, no seropositivity to either HTLV-I or -II was detected in the samples tested by a particle-agglutination assay for HTLV followed by type-specific Western blotting for HTLV. Reference to previous reports suggested that the rate of HIV infection in IVDAs has decreased with no HTLV-I or HTLV-II in Thailand when compared with that of the HIV infection in 1992.

Adolescent↗

PubMed1996

Measurement of pulmonary status and surfactant protein levels during dexamethasone treatment of neonatal respiratory distress syndrome.

BACKGROUND: Early postnatal use of dexamethasone in infants with respiratory distress syndrome (RDS) has been shown effectively to improve pulmonary status and to allow early weaning off mechanical ventilation. However, the mechanisms to explain the beneficial effects of dexamethasone in ventilatory dependent preterm infants remain unclear. METHODS: A double blind, placebo controlled study was performed to determine the change in pulmonary ventilation of premature infants with RDS as a result of dexamethasone treatment, and to evaluate the effect of dexamethasone on the levels of surfactant-associated proteins A (SP-A) and D (SP-D) in the tracheal fluid from 34 premature infants with RDS and 29 control subjects. RESULTS: Dexamethasone treatment decreased fractional inspired oxygen concentration (FIO2), arterial carbon dioxide tension (PCO2), mean airway pressure (MAP), and facilitated successful weaning from mechanical ventilation. SP-A concentrations in the tracheal aspirates were increased at days 7 and 14, and SP-D concentrations were increased during the period from days 3 to 14 in the dexamethasone treated group compared with the control group. However, albumin levels in the tracheal aspirate samples were decreased after dexamethasone treatment over the period from days 3 to 14. There was an inverse correlation between PCO2 values and SP-A concentrations. CONCLUSIONS: These results suggest that early use of dexamethasone can improve pulmonary status and also increase SP-A and SP-D levels in the tracheal fluid in premature infants with RDS.

Albumins↗

PubMed1996

Gene therapy against an experimental glioma using adeno-associated virus vectors.

The efficacy of gene therapy for glioma was examined using adeno-associated virus (AAV)-based vectors to deliver genes to experimental tumors in mice. Stereotactic injection of 2 x 10(5) U-251SP human glioma cells into the brains of nude mice produced tumors of 19.06 +/- 1.79 mm2 17 days after injection. Employing a high titer preparation of AAV vector containing the gene for beta-galactosidase (AAV-lacZ), dose-dependent transduction of U-251SP cells was seen in vitro. When 1.6 x 10(10) AAV-lacZ particles were directly injected into tumors in vivo, 30-40% of the cells along the needle track expressed beta-galactosidase. Transduction of U-251SP cells in vitro with an AAV vector containing a bicistronic gene encoding both herpes simplex thymidine kinase and human interleukin-2 (AAV-tk-IRES-IL2) rendered them sensitive to the cytocidal effects of ganciclovir (GCV) and IL-2 was produced in a dose-dependent manner. Cocultures of AAV-tk-IRES-IL2 transduced cells and nontransduced cells proved highly sensitive to GCV indicating the contribution of the bystander effect. Stereotactic delivery of 6 x 10(10) AAV-tk-IRES-IL2 particles into day 7 tumors in nude mice followed by administration of GCV for 6 days, resulted in a 35-fold reduction in the mean volume of tumors compared with controls. Normal brains did not suffer from any toxic effect of the administration of AAV-tk-IRES-IL2 and GCV. These results indicate that high titer AAV vector treatment may be safe and effective for in vivo gene therapy of human brain tumors.

Animals↗

PubMed1995

Analysis of proliferative activity using antiproliferating cell nuclear antigen antibody in colorectal cancer.

Using anti-PCNA antibody (PC10), an immunohistochemical study of the expression of PCNA in formalin-fixed and paraffin-embedded materials of colorectal cancer patients was performed and correlation of PCNA expression with clinicopathological findings and DNA ploidy pattern was studied. PCNA labeling rate (PCNA LR) was estimated in the advancing margin of the tumor and ranged from 23.8% to 77.9%. There was a significant difference in lymphatic vessel invasion, liver metastasis and Dukes' stage between the groups with high (> 48.7) and low (< 48.7) PCNA LR (P < 0.05). No differences were seen in tumor size, histological type, lymph node metastasis or DNA ploidy pattern. In patients with younger age, infiltration to neighboring organs, a high degree of venous invasion, and peritoneal dissemination, the frequency of high PCNA LR tended to be higher (P < 0.1). The results above suggest that a high proliferative activity as defined by evaluation of the PCNA LR at the advancing margin of the tumor may be one of the parameters of malignant potential and helpful as a predictor of liver metastasis in colorectal cancer.

Antibodies, Monoclonal↗

PubMed1995

Inhibitory effect of transferrin on progesterone production in the granulosa cell of humans in vivo and porcine granulosa cell in vitro.

We evaluated the effect of transferrin on the regulation of granulosa cell function in humans by evaluating the production of progesterone (P) in the preovulatory phase in vivo, and in cultured porcine granulosa cells in vitro. Twenty-five women treated for in vitro fertilization and embryo transfer had their serum levels of 17 beta-estradiol (E2) and P determined on the day of administration of human chorionic gonadotropin. Transferrin concentrations were also determined in ovarian follicular fluid. In an in vitro study, porcine granulosa cells were cultured in the presence of follicle-stimulating hormone (FSH) and transferrin. Serum levels of P showed a significant negative correlation with those of transferrin (r = -0.53, p < 0.01), whereas serum levels of E2 did not (r = 0.14). When the subjects were divided into two groups by serum P concentration (low P < 1 ng/ml, high P > or = 1 ng/ml) serum concentrations of transferrin were significantly increased in the group with the low versus the high level of p (p < 0.01). Production of P by porcine granulosa cells was suppressed by transferrin in the presence of various concentrations of FSH. Increasing the dose of transferrin significantly suppressed the production of P by those cells in a dose-dependent fashion. The production of P during the preovulatory phase may be suppressed by transferrin in the granulosa cells.

Adult↗

PubMed1995

Development and usefulness of the gelatin-particle-agglutination test for titration of antibodies against diphtheria, pertussis and tetanus toxins.

The gelatin-particle-agglutination (PA) test for titrating antibodies against diphtheria, pertussis and tetanus toxins was developed and used for assaying 65 sera from healthy children to assess the antitoxin acquisition in relation to the administration of adsorbed diphtheria-purified pertussis-tetanus (DPT) combined vaccine. The antitoxin titers obtained by the PA test and the conventional methods were correlated well; the correlation coefficient of the diphtheria antitoxin titers between the PA test and the cell culture method was 0.908, that of the tetanus antitoxin titers between the PA test and the passive hemagglutination test 0.968, and that of anti-pertussis toxin titers between the PA test and polystyrene-ball ELISA 0.885. The PA test was shown to be useful in both developed and developing countries, since it is simple to perform, sensitive and specific, and the three antitoxins can be titrated by the same procedure.

Agglutination Tests↗

PubMed1994

Parvovirus particles as platforms for protein presentation.

Empty capsids of the human pathogenic parvovirus B19 can be produced in a baculovirus system. B19 capsids are composed mainly of major capsid protein (VP2) and a small amount of minor capsid protein (VP1); VP1 is identical to VP2 but contains an additional 227-aa N-terminal region ("unique" region). A portion of that region of VP1 is external to the capsid, and VP1 is not required for capsid formation. We substituted the unique region with a sequence encoding the 147 aa of hen egg white lysozyme (HEL) and constructed recombinant baculoviruses with variable amounts of retained VP1 sequence joined to the VP2 backbone. After cotransfection with VP2 baculovirus and expression in insect cells, capsids were purified by density sedimentation. Purified recombinant capsids contained HEL. External presentation of HEL was demonstrated by immunoprecipitation, ELISA, and immune electron microscopy using anti-lysozyme monoclonal antibodies or specific rabbit antisera. Empty particles showed enzymatic activity in a micrococcal cell wall digestion assay. Rabbits inoculated with capsids made antibodies to HEL. Intact heterologous protein can be incorporated in B19 particles and presented on the capsid surface, properties that may be useful in vaccine development, cell targeting, and gene therapy.

Baculoviridae↗

PubMed1994

Surfactant protein D binding to alveolar macrophages.

Surfactant protein D (SP-D) is a lung-specific protein, synthesized and secreted by lung epithelial cells. It belongs to group III of the family of C-type lectins; each member of this group has an unusual overall structure consisting of multiple globular 'head' regions (which contain the C-type lectin domains) linked by triple-helical, collagen-like, strands. This group includes the surfactant protein A (SP-A) and the serum proteins mannan-binding protein, conglutinin and collectin-43, all of which have been shown to bind to the C1q receptor found on a wide variety of cells, including macrophages. Both SP-D and SP-A have been shown to enhance oxygen radical production by alveolar macrophages. Although this strongly suggests a direct interaction between SP-D and a specific receptor on alveolar macrophages, it is still unclear whether SP-D binds to the same receptor used by SP-A and/or C1q. Human SP-D was isolated from amniotic fluid and was radiolabelled using 125I. Alveolar macrophages were isolated from human bronchioalveolar lavage fluid, and also from bovine lung washings, by differential adhesion to 24-well tissue-culture plates. The study was carried out using EDTA-containing buffers, to eliminate Ca(2+)-dependent C-type lectin binding, and was also carried out at 4 degrees C to eliminate possible internalization by the cells. 125I-SP-D showed specific binding to alveolar macrophages in both a time- and concentration-saturable manner. The binding was inhibited, by approx. 90%, on addition of a 200-fold excess of unlabelled SP-D. The apparent dissociation constant (Kd) was (3.6 +/- 1.3) x 10(-11) M, based on the assumption that native SP-D is assembled as a dodecamer of 12 identical polypeptides of 43 kDa to yield a protein of 516 kDa. C1q was also shown to bind alveolar macrophages (Kd 3 x 10(-6) M), but addition of C1q did not show inhibition of the binding of 125I-SP-D to the macrophages. We conclude that SP-D binds specifically to alveolar macrophages and the receptor involved is different from that utilized by C1q.

Animals↗

PubMed1994

Surfactant proteins A (SP-A) and D (SP-D): levels in human amniotic fluid and localization in the fetal membranes.

Surfactant proteins A (SP-A) and D (SP-D) are major proteins, in the lung, which are composed of collagenous and globular domains. They show an overall similarity to the serum complement protein Clq, which is involved in the initiation of antibody-dependent defence mechanisms. Both SP-A and SP-D were detected, immunochemically, in amniotic fluid as early as 26 weeks gestation and, as expected, SP-A levels rose sharply from 32 weeks towards term. By contrast, SP-D levels in the same samples rose only moderately. Immunochemistry of paraffin sections of fetal membranes, revealed the presence of both SP-A and SP-D in the amniotic epithelium and chorio-decidual layers. SP-A and SP-D are both lectins and therefore they may play a role in the antibody-independent recognition and clearance of pathogens in the amniotic fluid.

Amniotic Fluid↗

PubMed1994

Nucleotide sequence comparison of the mycobacterial dnaJ gene and PCR-restriction fragment length polymorphism analysis for identification of mycobacterial species.

We recently reported a genus-specific PCR for the mycobacterial dnaJ gene. In the present study, we have determined the nucleotide sequences of the dnaJ gene from 19 mycobacterial species (Mycobacterium tuberculosis, M. bovis, M. bovis BCG, M. africanum, M. microti, M. marinum, M. kansasii, M. gastri, M. simiae, M. scrofulaceum, M. szulgai, M. gordonae, M. avium, M. intracellulare, M. xenopi, M. fortuitum, M. chelonae, M. hemophilum, and M. paratuberculosis). On the basis of the amplified dnaJ gene nucleotide sequences, we constructed a phylogenetic tree of the mycobacterial species by using the neighbor-joining method and unweighted pairwise grouping method of arithmetic average. We found that the phylogenetic relationship inferred within the slowly growing species was in good agreement with the traditional classification, with three major branches corresponding to Runyon's groups I, II, and III. An exception was M. simiae, which was phylogenetically closer to the cluster including members of Runyon's group III than to that of Runyon's group I. On the other hand, the rapid growers, such as M. fortuitum and M. chelonae, did not form a coherent line corresponding to Runyon's group IV, indicating that our phylogenetic analysis based on the dnaJ gene reflects the phenotypic characteristics such as pigmentation but not the growth rate. Finally, we revealed the species-specific restriction sites within the amplified dnaJ gene to differentiate most of the mycobacterial DNA by a combination of PCR with restriction fragment length polymorphism analysis.

Amino Acid Sequence↗

PubMed1994

Astrovirus as a cause of gastroenteritis in Japan.

We used an enzyme immunoassay (EIA) to screen for astrovirus in stool specimens from outbreaks and sporadic cases of gastroenteritis collected between 1982 and 1992 in six prefectural public health institutes in Japan. Three outbreaks of gastroenteritis involving schoolchildren and adults were confirmed to be attributable to astrovirus. Astrovirus was detected in 6 to 10% of the specimens from patients with sporadic gastroenteritis from whom no other bacterial or viral agent had been identified. Among the sporadic cases, astrovirus was most frequently detected in infants less than 1 year of age, and the incidence peaked in March and April. Using specimens from recent outbreaks, we found that the EIA was more sensitive than electron microscopy (EM) for the detection of astrovirus, and many EM-negative specimens were positive by EIA. However, some stool specimens previously found to have astrovirus-like particles by EM were negative by EIA, perhaps because of inadequate storage conditions, such as long-term storage and repeated freezings and thawings. Our results indicate that astrovirus is more commonly associated with childhood gastroenteritis than has been previously appreciated and suggest that further studies to examine the epidemiology and disease burden of this virus are needed.

Adolescent↗

PubMed1994

The transcriptional regulator YY1 binds to the 5'-terminal region of B19 parvovirus and regulates P6 promoter activity.

We performed a systematic study to identify cellular factors that bound to the terminal repeat region of B19 parvovirus. Using electrophoretic mobility shift assays, we detected one cellular factor which prominently bound to the repeat region. The factor was purified from K562 nuclear extract by specific DNA affinity column chromatography and identified as YY1, a multifunctional transcription factor. Of multiple possible YY1 binding sites in the upstream region of the P6 promoter, three showed specific strong binding. Transcription enhancement by YY1 was demonstrated in vitro by transient transfection assays. In studies using truncated and mutated versions of this region, YY1 activity was diminished by the alteration of any two of these three sites and abolished by the alteration of all three sites. Our results suggest that YY1 is a positive regulator of B19 parvovirus transcription.

Base Sequence↗

PubMed1994

Molecular evolution of the major capsid protein VP1 of enterovirus 70.

Nucleotide sequences of the genome RNA encoding capsid protein VP1 (918 nucleotides) of 18 enterovirus 70 (EV70) isolates collected from various parts of the world in 1971 to 1981 were determined, and nucleotide substitutions among them were studied. The genetic distances between isolates were calculated by the pairwise comparison of nucleotide difference. Regression analysis of the genetic distances against time of isolation of the strains showed that the synonymous substitution rate was very high at 21.53 x 10(-3) substitution per nucleotide per year, while the nonsynonymous rate was extremely low at 0.32 x 10(-3) substitution per nucleotide per year. The rate estimated by the average value of synonymous and nonsynonymous substitutions (W.-H. Li, C.-C. Wu, and C.-C. Luo, Mol. Biol. Evol. 2:150-174, 1985) was 5.00 x 10(-3) substitution per nucleotide per year. Taking the average value of synonymous and nonsynonymous substitutions as genetic distances between isolates, the phylogenetic tree was inferred by the unweighted pairwise grouping method of arithmetic average and by the neighbor-joining method. The tree indicated that the virus had evolved from one focal place, and the time of emergence was estimated to be August 1967 +/- 15 months, 2 years before first recognition of the pandemic of acute hemorrhagic conjunctivitis. By superimposing every nucleotide substitution on the branches of the phylogenetic tree, we analyzed nucleotide substitution patterns of EV70 genome RNA. In synonymous substitutions, the proportion of transitions, i.e., C<==>U and G<==>A, was found to be extremely frequent in comparison with that reported on other viruses or pseudogenes. In addition, parallel substitutions (independent substitutions at the same nucleotide position on different branches, i.e., different isolates, of the tree) were frequently found in both synonymous and nonsynonymous substitutions. These frequent parallel substitutions and the low nonsynonymous substitution rate despite the very high synonymous substitution rate described above imply a strong restriction on nonsynonymous substitution sites of VP1, probably due to the requirement for maintaining the rigid icosahedral conformation of the virus.

Base Sequence↗

PubMed1994

Clinical significance of minimal residual disease in leukemia detected by polymerase chain reaction: is molecular remission a milestone for achieving a cure?

Polymerase chain reaction (PCR) technology has been useful in clarifying molecular or minimal residual disease (MRD) status in patients with leukemia. Although PCR has several inherent problems, accumulated data have demonstrated that patients with leukemia harbor PCR-detectable residual disease for a certain period despite clinical remission. This has been for approximately 1 year in childhood acute lymphoblastic leukemia and adult acute promyelocytic leukemia after chemotherapy and for approximately 2 years in chronic myelogenous leukemia after bone marrow transplantation. Ultimately, PCR-undectable residual disease is necessary for achieving cures in most patients. However, it is difficult to make an early prediction of subsequent relapse after obtaining PCR negatively, since the emergence of PCR-detectable disease occurs only several months before clinical relapse. Therefore, PCR negativity is necessary but not sufficient for achieving cures in most patients with leukemia. Periods of persistent PCR-detectable disease will require further investigations for relapse prediction. More accurate serial quantitation would clarify a precise MRD status in leukemia patients and might allow for more accurate prediction of relapse. Since PCR-undectable residual disease is necessary for cures in most patients, it can be proposed that a "molecular remission", defined as PCR-undetectable disease, is a milestone and target for achieving cure by cytoreductive therapy.

Humans↗