Search PubMed⌕ Search

Biomedical subjects

K Takatsuki

Publications and source records attributed to K Takatsuki.

At least 199 records · Page 11Linked to original sources
PubMed1992

Accelerated declining tendency of human T-cell leukemia virus type I carrier rates among younger blood donors in Kumamoto, Japan.

The annual age- and sex-specific human T-cell leukemia virus type I carrier rate of blood donors in Kumamoto, Kyushu, Japan from 1986 to 1990 revealed that the carrier rates of all the age groups below 50 years declined linearly in both sexes (P less than 0.005). Furthermore, the annual declining rates relative to the carrier rates of 16-19-year-old and 20-29-year-old males were higher than those of all of the older males (P less than 0.02), and all female age groups below 50 years had higher relative declining rates than 50-64-year-old females (P less than 0.05). Although several factors, such as a notification program at obstetric clinics, methodological and technical improvement of the assays, wider knowledge of human T-cell leukemia virus type I infection in the latter years, and immigration of individuals from a nonendemic area, might cause an absolute decline of the carrier rate of the blood donors, these factors could not explain the acceleration of the relative declining rate among younger donors. Therefore, this acceleration represents the tendency of the general population.

Adolescent↗
PubMed1992

[HIV infections].

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Neutrophil chemotactic factors produced by a cell line from thyroid carcinoma.

A neutrophil chemotactic factor (human interleukin 8, human granulocyte-macrophage colony-stimulating factor)-producing cell line, named KHM-5M, was established from a patient with an undifferentiated thyroid carcinoma, neutrophilia, and malignant pleurisy with many neutrophils and a few malignant cells. The cell line was transplanted into nude rats, and the infiltration of neutrophils was observed in and around the transplanted tumor tissue. Neutrophil chemotactic activity was predicted from the clinical features and pathological findings in this case. The extreme chemotactic activity of the neutrophils was demonstrated in conditioned medium from KHM-5M cells using the modified Boyden chamber technique. With sodium dodecyl sulfate-polyacrylamide gel electrophoresis, at least two neutrophil chemotactic activities in conditioned medium from the cell line were observed. The levels of these activities derived from KHM-5M cells were screened by measuring conditioned medium from the COS cells, which expressed a complementary DNA library from the KHM-5M cells. Chemotactic activities (human interleukin 8, human granulocyte-macrophage colony-stimulating factor) were identified by DNA cloning. These results show that the KHM-5M cells derived from an undifferentiated thyroid carcinoma produce multicytokines and suggest that those cytokines modified some pathological features in this case.

Aged↗
PubMed1992

Mutations of the p53 gene in adult T-cell leukemia.

The p53 tumor suppressor gene was examined by direct sequencing of polymerase chain reaction-amplified DNA from fresh tumor cells of 10 patients with adult T-cell leukemia (ATL). Samples included nine patients with acute or lymphomatous ATL, and one patient in whom samples were examined in both his acute and chronic stages of ATL. Four missense mutations and one silent point mutation in the coding region of the p53 gene were found in cells from five patients with either acute or lymphomatous ATL. The missense mutations were homozygous and occurred in evolutionarily highly conserved regions of p53. One patient had no p53 mutation in his leukemic cells during chronic phase of ATL, but had a homozygous point mutation at codon 273 (Arg to His) when he progressed to acute ATL. In summary, we show that p53 is frequently mutated in the acute phase of ATL and one informative case suggests that p53 mutations may be associated with the transition from chronic to acute ATL.

Adult↗
PubMed1992

Effects of short-term administration of recombinant human erythropoietin on rat megakaryopoiesis.

Recombinant human erythropoietin (rHuEpo) was tested for its ability to stimulate rat megakaryopoiesis in vivo. Groups of Sprague-Dawley rats were injected with rHuEpo at a daily dose of 20, 80, or 200 U for 5 days. Significant thrombocytosis (a 30 to 40% increase over the control level) was found only in the rats that received 200 U/day, but some changes in the megakaryopoietic parameters were observed not only in the rats given 200 U/day, but also in those receiving 80 or 20 U/day. rHuEpo induced a dose-dependent elevation of megakaryocyte ploidy, with the maximum 45% increase in the mean ploidy over the control level seen in rats given 200 U/day. The size of the marrow megakaryocytes also increased dose-dependently. rHuEpo did not increase bone marrow megakaryocyte numbers, but it increased those in the spleen in a dose-dependent manner. A change of these parameters was seen as early as day 1 at 24 h after initiating the Epo injections at a time when significant thrombocytosis was already present. Moreover, a significant increase in the ratio of small acetylcholinesterase-positive bone marrow cells was also found, with the greatest response noted on day 1. Administration of a large dose of iron did not alter the thrombopoietic effect of rHuEpo. These results suggest that the in vivo administration of rHuEpo stimulates the maturation of mature as well as immature megakaryocytes already present in the bone marrow.

Animals↗
PubMed1992

Ganglioside-induced inhibition of in vivo immune response in mice.

In vitro immunomodulatory properties of gangliosides have been well characterized such as the ganglioside-induced modulation of CD4 on T lymphocytes and inhibition of lectin-induced proliferative response of lymphocytes. These findings have led to an interesting suggestion that gangliosides play a role as in vivo immune modulators, although this possibility is not clearly defined yet. We then first confirmed in vitro effects of gangliosides on murine immunocytes and examined in vivo effects of gangliosides on immune response in mice. Murine spleen cells that were treated with a ganglioside mixture (GS) purified from bovine brain exhibited a marked decrease in CD4 expression, while CD8 expression was slightly suppressed. Transplantation of GS-untreated control immunocytes that were isolated from syngeneic mice into the immune suppressed mice by X-ray irradiation restored in vivo immune responses, while GS-treated cells could not. Immune response was assayed by the evaluation of footpad swelling which was induced by immunization with sheep erythrocytes as antigens. Moreover, intramuscular administration of gangliosides into mice suppressed both immediate (Arthus)-type and delayed-type allergic reactions. These results suggest that gangliosides would be potential in vivo immune modulators.

Animals↗
PubMed1992

Characterization of a mouse/human chimeric monoclonal antibody (C beta 1) to a principal neutralizing domain of the human immunodeficiency virus type 1 envelope protein.

A chimeric mouse-human antibody (C beta 1) was constructed that recognized the principal neutralizing domain (PND) of human immunodeficiency virus type 1 (HIV-1) gp120. The constant (C) immunoglobulin regions (C gamma 1 and C kappa) of a mouse monoclonal antibody, 0.5 beta, were substituted for the human C gamma 1 and C kappa by recombining the DNA modules encoding variable or C regions. The DNA constructs were then transfected into X63 Ag8.653 myeloma cells. A clone with a high production of the chimeric antibody (C beta 1) was selected. This antibody was tested for its biological activity against HIV-1. It bound to the surface of HTLV-IIIB-infected cells and reacted with gp120/160 with equal affinity and specificity to that of the parental 0.5 beta murine monoclonal antibody in a Western blot assay. Neutralization and/or enhancement of HIV infection were evaluated with C beta 1 and 0.5 beta. Both C beta 1 and 0.5 beta neutralized cell-to-cell infection and cell-free virus infection by HTLV-IIIB. Antibody-dependence enhancement of HIV infection was not observed with either C beta 1 or 0.5 beta in the presence or absence of human complement. Antibody-dependent cell-mediated cytolysis (ADCC) and antibody-dependent complement-mediated cytolysis (ACC) were observed with C beta 1 but not with the parental 0.5 beta. These findings suggest that the neutralizing antibodies to PND may neutralize but not enhance HIV infection. Furthermore, the high levels of ACC and ADCC shown against HIV-infected cells by C beta 1 indicate that the clinical application of such monoclonal antibodies may be possible.

Amino Acid Sequence↗
PubMed1992

Dysregulation of adult T-cell leukemia-derived factor (ADF)/thioredoxin in HIV infection: loss of ADF high-producer cells in lymphoid tissues of AIDS patients.

Adult T-cell leukemia (ATL)-derived factor (ADF) is a multifunctional protein homologous to thioredoxin (TRX) with co-cytokine and thiol-dependent reducing activities. ADF/thioredoxin production is enhanced in T cells transformed by HTLV-I. We have examined the effect of HIV-1 infection on ADF/TRX expression using specific antibody against ADF/TRX. Lymph nodes from 5 AIDS and 1 AIDS-related complex (ARC) patients were examined. As a control, 8 HIV noninfected lymph nodes, including 3 cases with hyperplasia, were also examined. Immunohistopathological studies using normal HIV noninfected lymph nodes showed that ADF/TRX high-producer (ADFh) cells were macrophages and cells with dendritic morphology in the paracortical area. Abundant ADFh cells were observed in HIV noninfected hyperplastic lymph nodes. The number of ADFh cells was low in hyperplastic lymph nodes from an ARC patient. All of the lymph nodes of 5 AIDS cases were atrophic and the number of ADFh cells were extremely low. To verify these histochemical studies, we examined the effect of in vitro HIV infection on ADF/TRX expression in HTLV-I (+) T-cell lines. Western blot analysis showed that a reduction of ADF/TRX in HIV-1-infected SKT-1B and MT-2 cells, and the reduction inversely correlated with p24 antigen level. On the basis of the above in vivo and in vitro findings, we imply that the levels of ADF/TRX were down-regulated by HIV-1 infection and that the down-regulation may play a role for pathophysiology of HIV-infected individuals.

AIDS-Related Complex↗
PubMed1992

Changes in the reactivity and neutralizing activity of a type-specific neutralizing monoclonal antibody induced by interaction of soluble CD4 with gp120.

Antibodies directed against the third hypervariable loop-domain (V3 loop) of human immunodeficiency virus type 1 (HIV-1) gp120 inhibit the infection by HIV-1 in a type-specific manner without interfering with the binding of gp120 to CD4. Previous studies demonstrated that soluble CD4 (sCD4) induced the dissociation of gp120 with gp41 and caused conformational changes within the envelope oligomer. We report changes in the binding and neutralizing activity of a monoclonal antibody against the V3 loop after sCD4 binding to gp120. Flow cytometry revealed that a type-specific neutralizing monoclonal antibody against V3 loop of HTLV-IIIB, 0.5 beta, reacted with HTLV-IIIMN-infected cells after exposure to sCD4. When the sCD4-treated HTLV-IIIMN infected cells were analyzed by two-color flow cytometry, most of the CD4-bearing cells were 0.5 beta-positive, indicating that this reactivity of 0.5 beta was associated with the binding of sCD4 to the infected cells. To determine the cross-neutralization by 0.5 beta after exposure to sCD4, HTLV-IIIMN viruses pretreated with sCD4 were used to infect susceptible target cells. The addition of 0.5 beta significantly reduced the p24 antigen production (66.1 +/- 5.9 pg/ml) compared with a control murine IgG (221.3 +/- 15.3 pg/ml). In contrast, no significant reduction in the p24 antigen production was observed by adding the HTLV-IIIMN neutralizing monoclonal antibody, mu 5.5, (209.9 +/- 15.0 pg/ml). Taken together, these results suggest that sCD4/gp120 binding could induce conformational/antigenic changes within the V3 loop that result in the induction of cross-reactivity and cross-neutralizing activity of a type-specific monoclonal antibody.

Antibodies, Monoclonal↗
PubMed1992

HTLV-I uveitis: a distinct clinical entity caused by HTLV-I.

Seroepidemiological, clinical and virological studies were carried out in an HTLV-I endemic area to find out if HTLV-I caused an intraocular inflammatory disorder, uveitis. The seroprevalence in patients with uveitis without defined etiologies (62/175, 35.4%) was significantly higher than that in patients with non-uveitic ocular diseases (42/261, 16.1%) or in patients with uveitis with defined etiologies (8/78, 10.3%). Moreover, the seroprevalence in young adults (20-49 years) with uveitis without defined etiologies was 30/67 (44.8%), whereas it was only 10/107 (9.3%) in the other two groups. The uveitis in HTLV-I carriers was characterized clinically by a moderate inflammation of the vitreous body accompanied by a mild iritis and retinal vasculitis. The proviral DNA of HTLV-I was detected by polymerase chain reaction from the inflammatory cells in the anterior chamber in 9 out of 9 seropositive patients with the uveitis, but not in any of the tested patients with other types of uveitis. These data, thus, indicate that HTLV-I causes a specific type of intraocular inflammation, uveitis.

Adult↗
PubMed1992

Human T-cell leukemia virus-1-positive cell line established from a patient with small cell lung cancer.

A stable cell line, KHM-3S, was established from a patient with small cell lung cancer (SCLC), who had a high serum level of soluble interleukin 2 receptors (sIL2-R) and was seropositive for human T cell leukemia virus (HTLV)-1. KHM-3S cells were positive for IL2-R (Tac) and NKH-1, but negative for other lymphocytic markers such as OKT 11, OKT 4, OKT 8, T cell receptor (WT 31), B 1, and B 4. Moreover, the KHM-3S cells were negative for leukocyte common antigen and strongly positive for neuron-specific enolase (NSE). Secretion of sIL2-R and NSE by the KHM-3S line was detected by an enzyme-linked immunosorbent assay. Rearrangement of the T cell receptor gene and monoclonal HTLV-1 integration were found by Southern blot analysis of KHM-3S DNA. However, Northern blot analysis showed no T cell receptor mRNA. KHM-3S may be useful for studies on the role of HTLV-1 in carcinogenesis and IL2-R expression in SCLC.

Antigens, Surface↗
PubMed1992

Human myeloma cell line (KHM-4) established from a patient with multiple myeloma associated with hyperammonemia.

A cell line of plasma cells with high ammonia (NH3) production (KHM-4) was established from a patient with multiple myeloma complicated by hyperammonemia and abnormal serum concentrations of amino acids. Surface marker studies of KHM-4 cells showed that the cells were positive for cytoplasmic immunoglobulins (IgA kappa), HLA-DR, and T 10. Secretion of ammonia by the KHM-4 cells was detected by the addition of L-glutamine and L-arginine into the culture medium of amino acid-free RPMI 1640. In the presence of L-glutamine, KHM-4 cells secreted a greater amount of ammonia than the T cell line, CEM. However, production of ammonia by L-arginine was not observed in other cell lines. These observations provide evidence for the existence of a peculiar amino acid metabolism in the myeloma cells causing hyperammonemia and serum amino acid disturbance.

Ammonia↗
PubMed1992

[A case of primary alveolar hypoventilation syndrome with a good response to nocturnal low-flow oxygen inhalation and negative pressure ventilation].

A 34-year-old female was admitted on June 25, 1990, for the evaluation of alveolar hypoventilation which worsened after her second delivery. She showed impairment of both hypercapnic and hypoxic ventilatory responses, and marked desaturation due to hypopnea and apnea during sleep. Although administration of methylxanthine and medroxyprogesterone was not very effective, after treatment with low flow oxygen, there was a marked decrease in the frequency and duration of desaturation during sleep and improvement of arterial daytime blood gases, which suggested the existence of hypoxic ventilatory depression in the pathophysiology of her nocturnal desaturation. Furthermore, the use of a negative pressure ventilator for 3 hours in the daytime for 10 days resulted in marked improvement of symptoms, arterial blood gases, respiratory muscle strength, and the frequency and duration of sleep desaturation. These findings suggest that both low flow oxygen therapy during sleep, and daytime negative pressure ventilation may be beneficial in patients with primary alveolar hypoventilation and central sleep apnea syndrome.

Adult↗