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Biomedical subjects

J Hara

Publications and source records attributed to J Hara.

At least 91 records · Page 5Linked to original sources

Low frequency of the p53 gene mutations in neuroblastoma.

BACKGROUND: The p53 gene frequently is affected by point mutations, rearrangements, or deletions that contribute to the genesis or progression of a wide variety of human adult solid tumors; however, to the authors' knowledge, this gene alteration has not been analyzed in neuroblastoma. METHODS: Genomic DNA samples from 20 children with neuroblastoma, including 16 patients with advanced disease, were screened for the presence of mutations in exons 5-9 of the p53 gene, where over 90% of mutations have been reported to be located in human cancer. The screening technique employed polymerase chain reaction/single-strand conformation polymorphism analysis followed by direct DNA sequencing. RESULTS: Heterozygous mutations were detected in 2 of the 20 cases. A silent mutation (T to G transversion) at codon 172 and a missense mutation (G to T transversion) at codon 259 were found in patients with Stage II and Stage IV disease, respectively. Thus, p53 mutations were found to occur in neuroblastoma, but at a low frequency (2 of 20). CONCLUSIONS: Our data suggest that in a minority of neuroblastomas, p53 gene mutations may play a contributing role in tumorigenesis, but other genes presumably play a major role in this tumor.

Child↗

Phenotypic characteristics of acute megakaryocytic leukemia and transient abnormal myelopoiesis.

By immunophenotyping and ultrastructural cytochemistry, the disorders involving megakaryocytic lineage cells have been clarified. These disorders are termed acute megakaryocytic leukemia (AMKL) and transient abnormal myelopoiesis (TAM). The characteristics of blasts in these disorders have been extensively investigated from various standpoints including cytochemistry, cytogenetics, ultrastructure and in vitro-colony differentiation. The target cells of AMKL and TAM are immature cells close to stem cells which are capable of differentiating into lineage cells such as megakaryocytes, erythrocytes and myeloid cells. Phenotypically, these blasts frequently express antigens appearing at an early stage in the hematopoietic differentiation pathway. They thus often emerge as mixed phenotypes as seen in mixed lineage leukemia of immature cell origin.

Hematopoiesis↗

CD8+ lymphocyte counts and the risk of death in advanced HIV infection.

BACKGROUND: Mortality related to human immunodeficiency virus (HIV) infection occurs predominantly in patients with CD4+ lymphocyte counts of less than 50 cells/mm3. We followed 133 HIV-infected patients with enrollment CD4 counts of less than 50 cells/mm3 to determine if the risk of death during a 1-year period could be predicted by a single enrollment CD8+ lymphocyte count. METHODS: Enrollment data including age, sex, T-cell subset counts, p24 antigen status, antiretroviral use, and preexisting HIV-related illnesses were collected on a cohort of 133 consecutive patients with enrollment CD4 counts of less than 50 cells/mm3. The cohort was followed for 1 year, and survival data were analyzed in relation to enrollment variables. RESULTS: The mean enrollment CD8 count of those patients alive at 1 year was 600 cells/mm3, compared with a mean enrollment CD8 count of only 370 cells/mm3 in patients who had died prior to 1 year (P < .001). For every 100-cell decline in the enrollment CD8 count, the risk of death increased by 16% (95% confidence interval [CI], 5% to 22%), independent of other enrollment variables, including CD4 counts and p24 antigen status. A significant CD8 count warning level of 415 cells/mm3, irrespective of the presence of other enrollment variables, was associated with death within 1 year. The Kaplan-Meier estimated chance of death within 1 year was 54% (95% CI, 42% to 66%) for patients with CD8 counts of less than 415 cells/mm3 compared with only 25% (95% CI, 14% to 36%) for patients with CD8 counts greater than 415 cells/mm3. CONCLUSIONS: This study finds that a single CD8 count has important prognostic significance in patients with advanced HIV infection and suggests that potential therapies to enhance CD8 counts might be beneficial to patients with advanced HIV infection.

Acquired Immunodeficiency Syndrome↗

Immunization of the elderly and patients with collagen vascular diseases with live varicella vaccine and use of varicella skin antigen.

Elderly subjects and patients with collagen vascular diseases were immunized with a live varicella vaccine to assess the vaccine's potential for preventing herpes zoster. An improved varicella-zoster virus (VZV) skin test antigen was then used to assess cell-mediated immunity to VZV. The antigen was prepared from culture fluid of VZV-infected cells and had far less protein content than crude antigen prepared by sonication of infected cells. In 11 of 12 patients with ophthalmic zoster and 17 of 21 with dermal zoster, the skin reaction was negative at the beginning of the disease but became positive later. After two doses of VZV vaccine, 8 of 12 elderly subjects (greater than 60 years old) and 4 of 6 patients with collagen vascular diseases, who were VZV-skin test negative but purified protein derivative tuberculin test-positive, became VZV skin test-positive.

Adolescent↗

Mixed phenotype of blasts in acute megakaryocytic leukaemia and transient abnormal myelopoiesis in Down's syndrome.

Blasts from eight cases with acute megakaryoblastic leukaemia (AMKL) and seven with transient abnormal myelopoiesis in Down's syndrome (TAM) were investigated to clarify their phenotypic characteristics. CD41 and CD7 were the most frequently expressed in both disorders. CD41 was positive in six TAM and five AMKL cases, and CD7 was positive in five TAM and five AMKL cases, respectively. CD33 was detected in four TAM and five AMKL cases. Other myeloid-lineage associated antigens such as CD13 and CD11b could not be found in TAM but were expressed in five AMKL cases. Interestingly, CD56, a neural adhesion molecule, was expressed in three of four TAM and one of five AMKL cases. Cytoplasmic CD3 antigen was also noted in three of five examined cases. A short-term culture study was conducted on blasts from two TAM cases and five AMKL cases. In two cases in which CD41 was not expressed before culture, the expression of CD41 was enhanced after culture with or without 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The expression of CD7 remarkably was depressed, while that of CD13 was enhanced after culture with TPA. These findings suggest that blasts of TAM and AMKL originate from very immature cells and represent a mixed phenotype. In the present study, distinction of phenotypical differences between blast in TAM and AMKL was not possible.

Antigens, CD↗

Monocytes appearing repeatedly after chemotherapies had an identical rearrangement pattern of immunoglobulin with leukemic blasts in a patient with CD13+ acute lymphoblastic leukemia.

We recently encountered a patient with acute lymphoblastic leukemia (ALL) who showed temporal monocytosis of an unusually high cell count (5,000-30,000 monocytoid cells/microliter) five times after treatment with different chemotherapies. The leukemic cells expressed B-cell-associated antigens, CD19 and CD10, E-rosette receptor, CD2 and monocyte/myeloid antigen, CD13 simultaneously. They were peroxidase-negative. One week after the initiation of conventional chemotherapy for ALL, the leukemic blasts had disappeared. Alternatively, monocytoid cells appeared along with the recovery from nadir status. They showed several features of monocytes; they were weakly dot-positive for nonspecific esterase, reactive with CD14 and CD13 and Fc gamma-receptor-positive. Furthermore, they migrated into a fungally infected joint space. Features incompatible with normal monocytes were the absence of peroxidase reactivity, the expression of B-cell-associated antigens, CD19 and CD10 and E-rosette receptor, CD2. Southern blot hybridization analysis revealed an unexpected result that HindIII digested DNA from both leukemic blasts and monocytoid cells had the same rearranged band of IgH. Thus, an identical clonality of monocytoid cells, temporally appearing after chemotherapies and leukemic lymphoblasts, was determined in this patient with CD13+ ALL.

Antigens, CD↗

T-cell receptor alpha and delta gene assembly in B-cell precursor acute lymphoblastic leukemia.

The status of the TCR-alpha/delta genes in B-precursor ALL and the rearrangement patterns of these gene loci are discussed in this review. Although most of these rearrangements have been characterized, some still remain to be clarified. Almost all rearrangements of the TCRs in B-precursor ALL are incomplete and may reflect early recombinational steps during the TCR differentiation processes in normal T-lineage cells. In addition, even in T-cell malignancies, it is rarely possible to obtain clonal cell populations with TCR rearrangements arrested in very early recombinational steps. Therefore, studies of these as yet uncharacterized rearrangements may lead to the discovery of additional gene segments playing important roles in the TCR recombinational processes and may provide useful information for understanding the processes of T-cell differentiation.

Chromosome Mapping↗

Transient abnormal myelopoiesis in Down's syndrome.

Recent data have elucidated the pathogenesis of transient abnormal myelopoiesis (TAM) to a great extent. TAM is a monoclonal disorder which resolves spontaneously and the target cell in this disorder is a multipotent stem cell which is capable of differentiating into megakaryocytes. The pathogeneses of TAM/AMKL (acute megakaryoblastic leukemia) appears to be closely associated with abnormal quality and quantity of a gene located on chromosome 21. AMKL developing after the regression of TAM appears to come from the same clone as the TAM, which apparently experiences some kind of genetic alterations. It seems that the gene responsible for TAM will soon be cloned in the near future. However, the mechanism of spontaneous regression of TAM has as yet not been clarified. The expanding clone in the transient physiological immunodeficient state, during the perinatal period, might be eliminated with the maturation of more mature immunosurveillance. Alternatively, the TAM clone might be destined to undergo spontaneous death, which is called "programmed cell death" (apoptosis). The mechanism of this phenomenon awaits further elucidation.

Chromosome Aberrations↗

[Phenotypic and genotypic analysis of acute leukemia--current status of lineage specific classification].

More detailed identification and understanding of the heterogeneity of leukemias using a broad panel of markers seems to be essential for the successful design of more sophisticated and effective treatments. Based on the FAB system, immunological phenotypes using a panel of monoclonal antibodies, and rearrangements of immunoglobulin and T-cell receptor genes, acute leukemia can be divided into six subtypes such as B-lineage, T-lineage, AML, NK-lineage, AUL and mixed lineage leukemia. The definition of B-lineage and T-lineage cells, a new classification for mixed lineage leukemia, incidence of dual rearrangements and their clinical significance are discussed.

Acute Disease↗

Clinical significance of CD7-positive stem cell leukemia. A distinct subtype of mixed lineage leukemia.

Ten leukemia cases with mixed phenotype were investigated in terms of clinical characteristics and cellular origin. Three patients were infants and six patients were older children. Six of them had a high leukocyte count and a mediastinal mass was found in three cases. All but one showed hepatosplenomegaly and/or lymphoadenopathy. In spite of intensive chemotherapy, most of them responded poorly. Cytochemical analysis of their leukemic cells revealed a low percentage of positivity for myeloperoxidase reactivity (less than 25%) in two cases and electron microscopic platelet peroxidase reactivity was found in one of three analyzed cases. Phenotypically, these cells all expressed CD7, and other T-lineage-associated, B-lineage-associated, and/or myeloid-associated antigens were also detected to some extent. In addition, three cases expressed CD41 and one case expressed CD56. The T-cell receptor (TCR) genes and immunoglobulin gene were in the germline configuration in seven cases. In three rearranged cases, two showed only the TCR-delta gene rearrangement, and one had both TCR-gamma and delta gene rearrangements. Cell culture studies with 12-0-tetradecanoyl-phorbol-13-acetate (TPA) revealed differentiation to the T-lineage in two cases and to a myeloid lineage in one case. Megakaryocytic differentiation was detected in two cases in culture without TPA. These results suggest that the cells from these cases arose from stem cells capable of both lymphoid and nonlymphoid differentiation. Although the cells were heterogeneous with regard to their potency of differentiation, they have similar clinical characteristics. Because of poor prognosis, it is important to identify this type of leukemia, and allogenic or autologous bone marrow transplantation should be considered.

Acute Disease↗

Differential usage of delta recombining element and V delta genes during T-cell ontogeny.

We analyzed the usage of the delta recombining element (delta Rec) and six V delta genes in cell samples from 15 patients with CD3- and 10 patients with CD3+ T-cell acute lymphoblastic leukemia in an attempt to define the hierarchy of genetic events that is associated with the T-cell receptor (TCR) alpha/delta gene complex during T-cell ontogeny. Based on the deletion patterns of these genes, we surmised their relative order on chromosome 14 to be as follows: 5'-V delta 4, V delta 6, V delta 1, V delta 5, delta Rec, V delta 2, D delta 1-3, J delta 1-3, C delta, V delta 3-3'. In agreement with previous reports, V delta 1 was found to be preferentially rearranged in CD3+ samples. In CD3- samples, V delta 2 and V delta 3 rearrangements were observed at a high frequency. Incomplete V delta D delta rearrangements using V delta 2 or V delta 3, which are closest to C delta, were observed in three patients with CD3- and one patient with CD3+. These results suggest that V delta 2- and V delta 3-(Dn)D delta 3 recombinations are among the earliest recombinational events. Delta Rec was observed to be rearranged to phi J alpha on one allele. In addition, delta Rec rearrangements to J delta 1 and J alpha close to phi J alpha were also demonstrated on three alleles and one allele, respectively. Delta Rec rearrangements to J delta and J alpha other than phi J alpha also inhibit expression of the TCR delta locus. Approximately half of the alleles with J delta rearrangements showed no involvement of known V delta or delta Rec, indicating the existence of other, yet-uncharacterized V delta or delta Rec-like segments.

Antigens, Differentiation, T-Lymphocyte↗

Monoclonal nature of transient abnormal myelopoiesis in Down's syndrome.

Neonates with Down's syndrome occasionally show an excess of blasts in their peripheral blood. This disorder spontaneously resolves within several months and is called transient abnormal myelopoiesis (TAM) or transient myeloproliferative disorder. It has been uncertain whether the excess of blasts in TAM is a result of a clonal proliferation or a polyclonal reactive condition. The clonality of cells in females can be examined by analysis of the methylation patterns of the X chromosomes of proliferating cells using restriction fragment length polymorphism (RFLP). Using this strategy, we studied three females with Down's syndrome accompanied by TAM who showed heterozygosity in RFLP of either the hypoxanthine phosphoribosyltransferase or phosphoglycerate kinase gene. Analysis of the methylation patterns of these genes demonstrated a clonal nature for blasts in three patients. Thus, TAM is a clonal proliferative disorder. In addition, lymphocytes with a normal appearance contained in analyzed samples from these patients also showed a monoclonal pattern, suggesting that TAM may be a disorder of multipotent stem cells.

Bone Marrow↗

Establishment of a novel cell line with T-lineage phenotype (HPB-MLp-W) from a non-Hodgkin's lymphoma patient.

We report the characterization of a novel human T-cell line, HPB-MLp-W, which was established from blastic cells of a lymph node specimen from a patient with non-Hodgkin's lymphoma. They demonstrated the T-cell association antigens, CD2 and CD4, but no CD3, CD8, CD1, CD5, CD7 nor T-cell antigen receptor on their cell surfaces. They were also positive for Ia and Ki-1 antigen, and negative for CD25 (Tac-1). The cell line HPB-MLp-W had the same pattern of antigen expression as the patient's cells. Southern-blot analysis of DNA showed a rearrangement of the T-cell receptor-alpha and beta genes. To our knowledge, this is a novel cell line with unique T-lineage marker, to be established from a case of non-Hodgkin's lymphoma.

Antigens, CD↗

Inhibition of Legionella pneumophila in guinea pig peritoneal macrophages by new quinolone, macrolide and other antimicrobial agents.

The effect of 14 antimicrobial agents, including new quinolones and a new macrolide, on the intracellular multiplication of Legionella pneumophila in cultured guinea pig peritoneal macrophages was examined. Gentamicin and beta-lactam antibiotics did not inhibit the intracellular growth of L. pneumophila. Minocycline, erythromycin and DR-3355 inhibited multiplication at concentrations of 1, 0.5 and 0.1 mg/l respectively. Rifampicin, the new macrolide roxithromycin, and the new quinolones ofloxacin, ciprofloxacin and AT-4140 all inhibited the intracellular growth of L. pneumophila at concentrations of less than 0.03 mg/l. The minimal extracellular concentration inhibiting intracellular multiplication (MIEC), compared with conventional MIC measurements, provides a better indication of antimicrobial efficacy against bacteria, such as L. pneumophila, which can multiply in phagocytes.

4-Quinolones↗