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Biomedical subjects

T Oka

Publications and source records attributed to T Oka.

At least 289 records · Page 16Linked to original sources

Enhancing activity of mycobacterial cell-derived adjuvants on immunogenicity of recombinant human hepatitis B virus vaccine.

In a previous study, we demonstrated that a lipophilic derivative of muramyl dipeptide [MDP-Lys(L18)] augmented antibody response to recombinant human hepatitis B surface antigen (rhHBsAg) when it was co-immunized with rhHBsAg solubilized in PBS. Here, we examined adjuvant activity of two bacterial cell-derived adjuvants such as Bacillus Calmette-Guérin cell wall skeleton (BCG-CWS) and trehalose-6,6'-dimycolate (TDM), to enhance immunogenicity of rhHBsAg, comparing their activity with that of MDP-Lys(L18). In an animal model where mice were immunized subcutaneously (s.c.) with rhHBsAg (25 micrograms/mouse) admixed with 100 micrograms/mouse of BCG-CWS (Vac/BCG-CWS) or 50 micrograms/mouse of TDM (Vac/TDM) in o/w emulsion formulation, both mice immunized with Vac/BCG-CWS and Vac/TDM showed higher antibody titres to HB antigen than those of mice immunized with the recombinant vaccine alone. The activity of BCG-CWS and TDM to enhance antibody induction seemed to be almost the same with that of MDP-Lys(L18). Furthermore, the enhanced antibody response raised by these adjuvants was shown to be due to high titres of HB antigen-specific IgG1. In addition, the activity of these three adjuvants to enhance antibody response was shown to be higher than that of the present clinical vaccine, aluminium hydroxide-attached rhHBsAg (rhHBsAg-alum). In an analysis of delayed-type hypersensitivity (DTH) reaction where mice were immunized with rhHBsAg admixed with or without each adjuvant in o/w emulsion and followed by intrafootpad (i.f.) injection of rhHBsAg 4 weeks after immunization, mice immunized with Vac/BCG-CWS and Vac/TDM as well as Vac/MDP-Lys(L18) showed a significant increment of swelling reaction. These results suggest that BCG-CWS, TDM and MDP-Lys(L18) are potential adjuvants to enhance the immunogenicity of rhHBsAg to induce humoral and cellular responses.

Acetylmuramyl-Alanyl-Isoglutamine↗

Juxta-adrenal cortical cell nests or nodular formation in the younger generation: what does it mean?

The number and size of juxta-adrenal cortical cell nests or nodular formation (JACN) and their histology were examined in autopsy material from 255 successive subjects of various ages (from fetuses to elderly patients). The study of number and size showed that JACN occurred significantly more frequently among subjects aged 0-year-old (0Y0) to 10Y0 (p < 0.01) than among other age groups. The study of numbers within each nodular size range (large nodular formations [LNF; nodules with a minor axis measuring 0.25 mm or more] and small nodular formations [SNF; smaller than LNF]) showed that the number of SNF and the SNF to LNF ratio decreased according to age, while the number of LNF remained relatively constant. Immunohistochemical examination of proliferating adrenal cortical cells using the mouse anti-human antibody MIB-1 demonstrated many positive cells in subjects with many JACN. No nodular proliferation of adrenocorticotrophic hormone positive cells occurred in the adenohypophysis. Fibrous thickening of the adrenal capsule increased gradually with age or medication. JACN was very frequently observed among subjects with conditions such as asplenic syndrome, acute lymphocytic leukemia and Down's syndrome. These data suggest that JACN might be an anatomic variant but that certain factors could increase the size and number of JACN after birth.

Adenoma↗

Mutational analysis of the N-ras gene in acute lymphoblastic leukemia: a study of 125 Japanese pediatric cases.

A point mutation of the N-ras gene is one of the known genetic alterations identified in patients with acute lymphoblastic leukemia (ALL), but its clinical importance is still controversial. Using polymerase chain reactions, we examined codons 12, 13 and 61 of this gene in 125 Japanese childhood ALL patients (64 common-ALL, 22 pre-B-ALL, 33 T-ALL, 2 B-ALL, 3 undifferentiated ALL, and 1 unclassified ALL) including 9 relapsed patients. An N-ras point mutation was observed in 14 (11%) patients (9 common-ALL, 3 T-ALL, and 2 undifferentiated ALL; 13 patients at diagnosis and 1 at relapse). The patients with undifferentiated ALL harbored an N-ras mutation at a significantly higher rate. However, no correlation was found between the presence of an N-ras mutation and sex, age, or white blood count. There was no significant difference in the event-free survival rate between 13 fresh patients with an N-ras mutation and 103 patients with a wild-type configuration. The N-ras mutation was present in about 10% of childhood ALL cases but it did not have a prognostic impact. The sequence analyses revealed that the majority of the patients (13/14) had an N-ras mutation of a G to A transition. This finding was consistent with previous reports on N-ras mutations in acute leukemias in which the incidence of a G to A mutation was significantly higher in ALL than in myeloid malignancies.

Child↗

Ethanol administration delays recovery from acute pancreatitis induced by exocrine hyperstimulation.

Alcohol consumption causes acute alcohol pancreatitis and worsens the prognosis; however, there is no useful model for elucidation of the mechanism underlying this worsening. The aim of our study was to establish a new prognostic model of acute alcohol pancreatitis in rats. To ascertain the effect of continuous infusion of ethanol on each phase, i.e., progression and recovery, in caerulein-induced pancreatic injury in rats, we infused a physiological or supramaximal dose of caerulein intravenously to conscious Wistar rats for up to 6 h (time: 0-6 h) with or without ethanol infusion for 9 h (time: 3-12 h). Ethanol did not induce the pancreatic injury alone or when combined with a physiological dose of caerulein. In the progression phase, ethanol infusion for 3 h (time: 6 h) did not aggravate the pancreatic injury induced by a supramaximal dose of caerulein in terms of plasma amylase and lipase activities but did increase the pancreatic calcium level. In the recovery phase, however, ethanol infusion for 9 h (time: 12 h) significantly restrained the recovery from pancreatic injury as monitored in terms of these activities. Further, ethanol infusion for 9 h significantly increased the cumulative urinary excretion of amylase from 12 to 27 h but did not do the same from 0 to 12 h. In the histological evaluation at 27 h, the induction of acinar cell vacuolization and dilation of the glandular lumina and ducts were significant in the caerulein plus ethanol-treated group. Our findings suggest that ethanol administration delays the recovery rather than worsens the progression in acute pancreatic injury induced by exocrine hyperstimulation, and we consider our experimental model to be a useful tool for studying the pathogenesis of worsening prognosis in acute alcohol pancreatitis.

Acute Disease↗

Systemic administration of rIL-12 synergistically enhances the therapeutic effect of a TNF gene-transduced cancer vaccine.

Interleukin-12 (IL-12) is a potent antitumor cytokine, which induces and enhances the activity of natural killer (NK) cells, lymphokine activated killer (LAK) cells and cytotoxic T lymphocytes (CTL). IL-12 also stimulates IFN-gamma production from both T cells and NK cells. In this study, we transfected methylcholanthrene-induced fibrosarcoma (MCA-D) with TNF gene and investigated the therapeutic effect of TNF gene-transduced cancer vaccine and whether the vaccination effect is enhanced by systemic administration of recombinant IL-12 (rIL-12), in a murine model. TNF gene-transduced cancer vaccine or systemic administration of rIL-12 showed slight or moderate inhibition of pre-established tumor. However, simultaneous application of the vaccine and rIL-12 resulted in complete eradication. The cytotoxicity of CTL against parental tumor cells was enhanced with the combination of the vaccine and rIL-12, and IFN-gamma production from spleen cells also increased synergistically. Our findings show that synergistic enhancement of CTL activity and IFN-gamma production could play an important role in the antitumor effect of combination therapy using TNF gene-transduced cancer vaccine and rIL-12.

Adjuvants, Immunologic↗

Evidence for specific immune response against P210 BCR-ABL in long-term remission CML patients treated with interferon.

Interferon-alpha treatment induces complete cytogenetic remission in 25% of Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML) patients. These remissions are durable unlike remissions induced with other therapies and yet residual leukemia is detectable in most of these patients. Total peripheral blood mononuclear cells (PBMCs) from CML patients in long-term remission following interferon treatment exhibited significantly higher proliferative responses (four- to 15-fold over background) than normals directed against P210 BCR-ABL in extracts of transfected monkey fibroblast cells. Surprisingly, similar enhanced levels of specific proliferative responses were observed with extracts from cells expressing Bcr and/or Abl proteins. In contrast, extracts from vector only or v-Mos-expressing cells had background level responses. Control monkey fibroblast cells lacking BCR-ABL expression failed to induce proliferation over background levels. Normal individuals had no significant responses to Bcr/Abl extracts. On the other hand, peripheral blood mononuclear cells from allogeneic bone marrow transplant CML patients had proliferative responses to cell extracts independent of Bcr-Abl. These data indicate that patients in remission due to alpha-interferon treatment have significantly higher levels of specific cellular immunoreactivity against Bcr/Abl sequences than normal controls, which could play a role in maintaining cytogenetic remission in Ph-positive CML patients.

Adult↗

H3+ in dense and diffuse clouds.

Interstellar H3+ has been detected in dense as well as diffuse clouds using three 3.7 microns infrared spectral lines of the nu 2 fundamental band. Column densities of H3+ from (1.7-5.5) x 10(14) cm-2 have been measured in dense clouds in absorption against the infrared continua of the deeply embedded young stellar objects GL2136, W33A, MonR2 IRS 3, GL961E, and GL2591. Strong and broad H3+ absorptions have been detected in dense and diffuse clouds towards GC IRS 3 and GCS3-2 in the region of the galactic center. A large column density of H3+, comparable to that of a dense cloud, has been detected towards the visible star Cygnus OB2 No. 12, which has a line of sight that crosses mostly diffuse clouds. The H3+ chemistry of dense and diffuse clouds are discussed using a very simple model. Some future projects and problems are discussed.

Astronomical Phenomena↗