Search PubMed⌕ Search

Biomedical subjects

H Okamura

Publications and source records attributed to H Okamura.

At least 235 records · Page 13Linked to original sources
PubMed1998

IFN-gamma-inducing factor/IL-18 administration mediates IFN-gamma- and IL-12-independent antitumor effects.

We evaluated the mechanism of the antitumor effects of mouse rIFN-gamma-inducing factor/IL-18 protein on the growth of mouse tumor cell lines in vivo. Mice received IL-18 before or after challenge with CL8-1, a mouse melanoma cell line. Both regimens significantly suppressed tumor growth and reduced the number of mice with growth of tumor from 60% (3/5) to 20% (1/5). Furthermore, IL-18 administered before and after tumor inoculation completely abrogated the establishment of CL8-1 in all animals. IL-18 administration also significantly suppressed the growth of MCA205, a sarcoma cell line, even when treatment was delayed to 7 days following tumor inoculation. Although IL-18/IL-12 combination therapy had the most significant and immediate antitumor effects, many mice so treated succumbed with markedly elevated serum IFN-gamma levels. The antitumor effects of IL-18 were abrogated almost completely when NK cells were eliminated using anti-asialo GM1 Ab administration, but only marginally impaired in IFN-gamma or IL-12 gene-disrupted mice. Immunohistochemical staining revealed that the number of the CD8+ T cells, but not CD4+ T cells, found at the tumor site was reduced in animals treated with IL-18. These results indicate that IL-18 has potent antitumor effects mediated by CD4+ T cells and NK cells, but in IFN-gamma- and IL-12-independent pathways.

Adjuvants, Immunologic↗
PubMed1998

Interleukin 18 inhibits osteoclast formation via T cell production of granulocyte macrophage colony-stimulating factor.

IL-18 inhibits osteoclast (OCL) formation in vitro independent of IFN-gamma production, and this was abolished by the addition of neutralizing antibodies to GM-CSF. We now establish that IL-18 was unable to inhibit OCL formation in cocultures using GM-CSF-deficient mice (GM-CSF -/-). Reciprocal cocultures using either wild-type osteoblasts with GM-CSF -/- spleen cells or GM-CSF -/- osteoblasts with wild-type spleen cells were examined. Wild-type spleen cells were required to elicit a response to IL-18 indicating that cells of splenic origin were the IL-18 target. As T cells comprise a large proportion of the spleen cell population, the role of T cells in osteoclastogenesis was examined. Total T cells were removed and repleted in various combinations. Addition of wild-type T cells to a GM-CSF -/- coculture restored IL-18 inhibition of osteoclastogenesis. Major subsets of T cells, CD4+ and CD8+, were also individually depleted. Addition of either CD4+ or CD8+ wild-type T cells restored IL-18 action in a GM-CSF -/- background, while IL-18 was ineffective when either CD4+ or CD8+ GM-CSF -/- T cells were added to a wild-type coculture. These results highlight the involvement of T cells in IL-18-induced OCL inhibition and provide evidence for a new OCL inhibitory pathway whereby IL-18 inhibits OCL formation due to action upon T cells promoting the release of GM-CSF, which in turn acts upon OCL precursors.

Animals↗
PubMed1998

IL-18 (IFN-gamma-inducing factor) regulates early cytokine production in, and promotes resolution of, bacterial infection in mice.

IL-12-induced IFN-gamma production is essential for clearance of Yersinia enterocolitica infection. Similar to IL-12, the recently described cytokine IL-18 (IFN-gamma-inducing factor) is produced by macrophages and induces IFN-gamma production in spleen cells. Therefore, we have investigated the role of IL-18 in Yersinia infection of mice. Heat-killed yersinia-triggered IL-18-promoted IFN-gamma production of splenocytes was predominantly dependent on endogenous IL-12 production, whereas IL-12-promoted IFN-gamma production was not IL-18 dependent. IL-18-induced IFN-gamma production was to a higher degree dependent on IFN-gammaR-mediated mechanisms and in synergism with IL-2 resulted in at least fivefold higher IFN-gamma levels as compared with the combination of IL-12 plus IL-2. Analysis of the effect of IL-18 on IL-12 production of LPS-stimulated peritoneal macrophages revealed that IL-18 decreased LPS-induced IL-12 production, indicating that IL-18 might be involved in negative regulation of IL-12 production. In vivo studies revealed that Yersinia-resistant C57BL/6 mice expressed fourfold higher IL-18 mRNA levels than did susceptible BALB/c mice. Administration of anti-IL-18 Abs caused a 100- to 1000-fold increase in bacterial counts in the spleen of infected mice but did not change IFN-gamma production levels. Taken together, our data demonstrate that IL-18 is involved in regulation of cytokine production during the early phase of bacterial infections as well as in clearance of Yersinia infection.

Animals↗
PubMed1998

Establishment of a new cell line, OKT1, from small cell carcinoma secreting ectopic ACTH of the uterine cervix.

OBJECTIVE: Small cell carcinoma of the uterine cervix is rare and represents a unique entity among gynecological tumors. It sometimes demonstrates neuroendocrine differentiation, including adrenocorticotropin (ACTH) secretion. In this study, we established a new cell line, OKT1, from a case of carcinoma secreting ectopic ACTH without Cushing's syndrome and determined the character of the cell line. METHODS: OKT1 was established from OKT tumor cells, derived from a biopsy specimen of small cell cervical carcinoma, and serially heterotransplanted into nude mice. To characterize OKT1, the cell morphology, growth properties, immunohistochemical properties, hormone- and tumor-associated antigen secretion, tumorigenic potential, DNA profile, and chromosomal alteration were studied. RESULTS: The population doubling time of OKT1 was approximately 27 h. The cytological properties of OKT1, including DNA ploidy pattern, were similar to those of the primary tumor. Neuroendocrine differentiation was shown in the OKT1 cells by the positive immunocytochemical staining of neuron-specific enolase (NSE) and the presence of NSE and ACTH in the culture media. The xenograft of 1 x 10(8) OKT1 cells into nude mice yielded tumor mass. Furthermore, OKT1 demonstrated HPV type 18 and absence of a p53 gene mutation from exons 5 through 8. CONCLUSION: To our knowledge, OKT1 is the first cell line established from small cell cervical carcinoma with ACTH secretion.

Adrenocorticotropic Hormone↗
PubMed1998

Predictive factors for psychological distress in ambulatory lung cancer patients.

Although there is a need for systematic research on the psychosocial issues faced by lung cancer patients, there have been few studies in this area. The objective of the present study was to investigate potential predictors of psychological distress among ambulatory lung cancer patients. The variables examined included the patients' characteristics, coping responses, and social support factors. Lung cancer patients completed the Profile of Mood States (POMS) and the Mental Adjustment to Cancer scale (MAC scale), and information pertaining to demographic variables and social support factors was obtained from them at a structured interview. Evaluable data were obtained from 87 patients. The results of multiple regression analysis indicated that female gender, living alone, no children in the role of confidant, nurses as confidants, and helplessness/hopelessness as a coping style were predictive for psychological distress. Information on patients' demographic variables and psychosocial correlates of psychological distress may later be useful in developing interventions to facilitate their adjustment to lung cancer.

Adaptation, Psychological↗
PubMed1998

Full-length GBV-C/HGV genomes from nine Japanese isolates: characterization by comparative analyses.

The genomes of nine GBV-C/HGV isolates from Japanese chronic hepatitis patients were fully sequenced and characterized. They shared 85% nucleotide sequence homology with previously characterized isolates from the US and West Africa. Homology studies and phylogenetic analyses showed that the Japanese isolates formed a third group distinct from the established groups 1 and 2. The genetic distances between the three groups of GBV-C/HGV were very similar to the distances between the two classical swine fever virus (CSFV) serotypes, which suggested that they might belong to a separate GBV-C/HGV serotype. Plot similarity analysis comparing the three groups exposed relatively conserved terminal non-coding regions. Hairpin structures predicted in the Japanese isolates are probably involved in viral replication. The region coding E1-E2-NS-2 showed the least similarity (80%); in HCV the similarity here is only 50% due to its hypervariability. NS-3 and NS-5b that respectively encode the helicase/protease and RNA-dependent RNA polymerase, had a high degree of amino acid homology, suggesting a high degree of functional constraint in this region. The NS-5b nucleotide sequence was highly conserved perhaps because of constraints from RNA secondary structure and/or an open reading frame in the negative strand.

Base Sequence↗
PubMed1998

Changes in macrophage colony-stimulating factor concentration in serum and follicular fluid in in-vitro fertilization and embryo transfer cycles.

OBJECTIVE: To evaluate the changes of macrophage colony-stimulating factor concentration in serum and compare macrophage colony-stimulating factor concentration in follicular fluid (FF) through IVF-ET cycles. DESIGN: Sera and the matched FFs were collected serially through the IVF-ET cycles and analyzed retrospectively with respect to macrophage colony-stimulating factor concentration. SETTING: Department of Obstetrics and Gynecology of Kumamoto University Hospital. PATIENT(S): Ninety-four women underwent 129 cycles of ovulation induction by using GnRH agonist (GnRHa)-hMG-hCG for IVF-ET program. INTERVENTION(S): Serum and FF macrophage colony-stimulating factor concentrations were measured by ELISA. MAIN OUTCOME MEASURE(S): Concentrations of macrophage colony-stimulating factor in serum and FF. RESULT(S): Serum macrophage colony-stimulating factor concentration was gradually increased throughout ovarian stimulation, and reached a peak from the day of oocyte retrieval to 2 days after oocyte retrieval, whereas no significant change in macrophage colony-stimulating factor was observed in cases of poor ovarian response to hMG. The macrophage colony-stimulating factor concentration in follicles was significantly higher than that in sera on the day of oocyte retrieval, and the concentrations in follicles from which oocyte could be retrieved were significantly higher than those from which oocyte could not be retrieved. CONCLUSION(S): These results suggest that gonadotropins lead to an increase in ovarian macrophage colony-stimulating factor production, and that this macrophage colony-stimulating factor production in response to hMG administration is lost in poor ovarian responders. Thus, macrophage colony-stimulating factor may play an important role in the process of follicular maturation and ovulation as an intraovarian regulator.

Adult↗
PubMed1998

Analysis of the cytokine interaction among interleukin-1beta, interleukin-8, and interleukin-1 receptor antagonist in the rabbit ovulatory process.

OBJECTIVE: To elucidate the regulation and involvement of interleukin (IL)-1beta, IL-8, and IL-1 receptor antagonist in the hCG-induced rabbit ovulatory process. DESIGN: Randomized, controlled animal study. SETTING: University research laboratory. ANIMAL(S): Mature female New Zealand white rabbits. INTERVENTION(S): After i.v. administration of 100 IU of hCG to rabbits, ovarian levels of IL-1beta. IL-8, and IL-1 receptor antagonist were determined at indicated times by ELISA. Anti IL-1beta, anti-lL-8, or anti-IL-1 receptor antagonist antiserum was given i.v. 30 minutes before hCG injection. MAIN OUTCOME MEASURE(S): Effects of each antiserum on the levels of the other cytokines and neutrophil accumulation, assessed by myeloperoxidase activity, were determined. Ovulation rate (rate of ruptured follicles) was also evaluated. RESULT(S): The maximal level of IL-8 was detected at 4 hours. which preceded that of IL-1beta and IL-1 receptor antagonist, detected at 6 hours after hCG injection. Administration of anti-IL-1beta antiserum resulted in a statistically significant reduction of the peak levels of IL-8 and IL-1 receptor antagonist. Administration of anti-IL-8 antiserum reduced the accumulation of IL-1beta and IL-1 receptor antagonist. Anti-IL-1 receptor antagonist antiserum significantly augmented the accumulation of IL-1beta and IL-8. Myeloperoxidase activity was reduced by anti-IL-8 antiserum. Anti-IL-1beta and anti-lL-8 antiserum reduced the hCG-induced ovulation rate, but a synergistic effect was not evident when these antisera were injected simultaneously. Anti-IL-1 receptor antagonist antiserum had no apparent effect on ovulatory efficiency. CONCLUSION(S): IL-1beta, IL-8, and IL-1 receptor antagonist may affect the accumulation of related cytokines in ovaries and may be involved in ovulation.

Animals↗
PubMed1998

Protection of chickens with or without maternal antibodies against both Marek's and Newcastle diseases by one-time vaccination with recombinant vaccine of Marek's disease virus type 1.

We constructed a stable recombinant Marek's disease virus type 1 (rMDV1) expressing the fusion protein (F) of Newcastle disease virus (NDV) by inserting the coding sequence within the US10 gene of MDV1 by homologous recombination and designated this as rMDV1-US10L(F). The NDV-F protein was significantly expressed under control of the SV40 late promoter in cultured cells infected with the rMDV1. To examine the protective efficacy of the rMDV1, specific pathogen-free (SPF) chickens were vaccinated with rMDV1 at one-day-old. Almost all birds (> 95%) were protected from NDV challenge via intramuscular, ocular, intranasal and intratrachial routes at 4 weeks after vaccination. The rMDV1 showed 100% protection against virulent MDV1 challenge in SPF chickens. Antibody responses against NDV-F and MDV1 antigens were observed at least up to 11 weeks after immunization. When the sera from chickens vaccinated with the rMDV1 were examined for the presence of anti-NDV-F antibody on the day of NDV challenge, the vaccinated bird group which did not survive from NDV challenge were found to show lower antibody titers than the surviving group. The rMDV1 also provided sufficient protection against NDV and MDV1 challenges in commercial chickens with maternal antibodies against NDV-F and MDV1 antigens.

Animals↗
PubMed1998

Rare case of autoimmune hyperchylomicronemia during pregnancy.

A pregnant woman was found to have severe hypertriglyceridemia, fasting chylomicronemia, and low platelet count. The activities of serum lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) proved to be extremely low. The activities of the enzymes in normal plasma were completely inhibited by addition of the patient's plasma. We concluded that autoantibodies to lipases were responsible for this patient's hypertriglyceridemia.

Adult↗
PubMed1998

Neuron-glia interaction in the suprachiasmatic nucleus: a double labeling light and electron microscopic immunocytochemical study in the rat.

The morphological interactions between astroglial and neuronal elements were elucidated in the rat suprachiasmatic nucleus (SCN) by light and electron microscopic immunocytochemistry using antibodies against glial fibrillary acidic protein (GFAP), vasoactive intestinal peptide (VIP) and arginine-vasopressin (AVP). Throughout the SCN, particularly in its ventral portion, GFAP-like-immunoreactive (GFAP-LI) astroglial elements were found. These astrocytes displaying GFAP-like immunoreactivity occasionally contained fairly well-developed organelles. Some of these astrocytes were found as satellite cells in close contact with non-immunoreactive neuronal perikarya and processes. Around the neurons, GFAP-LI astroglial processes were also observed to cover some portions of presynaptic and postsynaptic elements. In addition, these astroglial elements were seen between two neuronal somata and pericytes of blood capillaries as glial endfeet. By double labeling immunoelectron microscopy using antibodies against GFAP/VIP and GFAP/AVP, some portions of VIP-like-immunoreactive or AVP-like-immunoreactive neuronal somata and processes were found to be engulfed by GFAP-LI astroglial processes. The possible functional roles of the morphological interactions between astroglial and neuronal elements are discussed.

Animals↗
PubMed1998

Regulation of interferon-gamma production by IL-12 and IL-18.

IL-18 (interferon-inducing factor) and IL-12 exhibit a marked synergism in interferon-gamma induction in T cells. Investigations into the mechanism of this synergism have revealed that IL-12 upregulates expression of the IL-18 receptor on cells producing interferon-gamma. Although IL-18 does not induce the development of Th1 cells, it is essential for the effective induction and activation of Th1 cells by IL-12. As for natural killer cells, IL-18 seems to activate them independently of IL-12. Although IL-12 and IL-18 activate both innate and acquired immunity, their excessive production by activated macrophages may induce multiple organ disorders including disruption of the immune system.

Animals↗
PubMed1998

Defective NK cell activity and Th1 response in IL-18-deficient mice.

IL-18 is a cytokine that is secreted from activated macrophages and induces IFNgamma production. To investigate the in vivo role of IL-18, we generated IL-18-deficient mice. In Propionibacterium acnes (P. acnes)-primed IL-18-deficient mice, LPS-induced IFNgamma production was markedly reduced, despite normal IL-12 induction. Natural killer cell activity was significantly impaired. Th1 cell response after injection of P. acnes or Mycobacterium bovis (bacillus Calmette-Guerin [BCG]) was significantly reduced. Similar results were observed in IL-12-deficient mice. Interestingly, Th1 response was induced after BCG infection in IL-12-deficient mice. We therefore generated mice lacking both IL-18 and IL-12. In these mice, NK activity and Th1 response were further impaired. This demonstrates the important role of both IL-18 and IL-12 in NK activity, as well as in in vivo Th1 response.

Animals↗
PubMed1998

Selective inhibition of NFAT activation by a peptide spanning the calcineurin targeting site of NFAT.

NFAT transcription factors play a key role in the immune response. The activation of NFAT proteins is controlled by calcineurin, the calmodulin-dependent phosphatase that is inhibited by the immunosuppressive drugs cyclosporin A and FK506. Here we identify a short conserved sequence in NFAT proteins that targets calcineurin to NFAT. Mutation of a single residue in this sequence impairs the calcineurin-mediated dephosphorylation and nuclear translocation of NFAT1. Peptides spanning the region inhibit the ability of calcineurin to bind to and dephosphorylate NFAT proteins, without affecting the phosphatase activity of calcineurin against other substrates. When expressed intracellularly, a corresponding peptide inhibits NFAT dephosphorylation, nuclear translocation, and NFAT-mediated expression in response to stimulation. Thus, disruption of the enzyme-substrate docking interaction that directs calcineurin to NFAT can effectively block NFAT-dependent functions.

Amino Acid Sequence↗
PubMed1998

Predictors of patients' mental adjustment to cancer: patient characteristics and social support.

Because being diagnosed with cancer is considered to be extremely stressful, cancer patients' mental adjustment has been widely studied. Previous studies have revealed that cancer patients' mental adjustment is correlated with the quality of life and the degree of psychological distress and have suggested that one of the most adaptive adjustments is 'fighting spirit' whereas one of the most maladaptive is 'helplessness/hopelessness'. However, little is known about the association between patients' mental adjustment to cancer and their spouses characteristics or social support network. This paper describes a study of cancer patients' characteristics and social support factors as predictors of the patients' responses to having cancer. A total of 455 ambulatory cancer patients completed the Mental Adjustment to Cancer (MAC) scale and participated in a structured interview about their characteristics and social support. The results of multiple regression analysis suggested that size of household, performance status, support from physicians and satisfaction with support were predictive of patients' fighting spirit, whereas age, education, size of household, performance status and satisfaction with support were predictive of helplessness/hopelessness.

Adolescent↗
PubMed1998

A new mammalian period gene predominantly expressed in the suprachiasmatic nucleus.

BACKGROUND: In mammals, two possible clock genes (Clock, Per1) have very recently been reported. mPer1 (the first identified mouse period gene), in particular, shows a circadian expression in suprachiasmatic nuclei (SCN), the mammalian circadian centre. However, only mPer1 and Clock as clock components may not be sufficient to understand all the events in circadian oscillation and entrainment. RESULTS: A mammalian period complementary DNA, mPer2, has been isolated from the mouse brain. The amino acid sequence of mPer2 is similar to mPer1 and Drosophila Period (dPer), indicating that mPer2 is a member of the family which contains mPer1, itself a homologue of dPer. mPer2 mRNA is predominantly expressed in SCN. A robust circadian rhythmic expression in the SCN supports the view that mPer2 is a clock gene. mPer2 is strongly expressed at the subjective afternoon in constant darkness, distinct from a morning-phase clock mPer1. Our precise quantitative in situ hybridizations have revealed that the peak expression of mPer2 transcripts is delayed by 8 h in LD (light-dark) or 4 h in DD (dark-dark) conditions when compared to mPer1. A short brief light exposure at the early subjective night, prompting a phase-shift in locomotor rhythms, induces a transient increase of mPer2 transcripts with delayed onset, as compared to mPer1 mRNA induction. Furthermore, mPer2 is co-expressed with mPer1 in single SCN cells. CONCLUSIONS: Mammalian period genes show molecular heterogeneity, each of which is composed of a different oscillator, and may serve to establish stable circadian rhythms in mammalian oscillating cells.

Amino Acid Sequence↗