Biomedical subjects

H Okamura

Publications and source records attributed to H Okamura.

At least 73 records · Page 4Linked to original sources

PubMed2001

IL-12 and IL-18 are increased and stimulate IFN-gamma production in sarcoid lungs.

Sarcoidosis is a systemic chronic granulomatous disease of unknown cause. Recent investigations revealed that the cytokine profile in inflamed lesions of sarcoidosis is Th1 dominant. To obtain better immunopathologic understanding of sarcoidosis, we examined the expression of IL-12 and IL-18 and their roles in IFN-gamma production in pulmonary sarcoidosis. Sarcoid cases had significantly elevated levels of IL-12 (p40 and p70) and IL-18 in bronchoalveolar lavage (BAL) fluids compared with healthy subjects. IL-12 p70 and IL-18 were immunohistochemically expressed in the epithelioid cells and giant cells of sarcoid granulomas. Significant induction of IFN-gamma, IL-12 p70, and IL-18 was observed from sarcoid BAL fluid cells with LPS stimulation, whereas LPS tended to induce only IL-12 p70 in BAL fluid cells from healthy subjects. Sarcoid cases had significantly greater IFN-gamma induction with LPS stimulation than healthy subjects did. IL-18 mRNA expression was observed in freshly isolated sarcoid BAL fluid cells as well as in LPS-stimulated sarcoid BAL fluid cells, but IFN-gamma and IL-12 mRNA expression was observed only in LPS-stimulated BAL fluid cells. Treatment with anti-IL-12- and anti-IL-18-neutralizing Abs significantly inhibited IFN-gamma production from LPS-stimulated BAL fluid cells of sarcoid cases. Coadministration of rIL-12 or rIL-18 induced greater IFN-gamma production in sarcoid BAL fluid cells than in normal BAL fluid cells. We concluded that bioactive IL-12 and IL-18 were produced in sarcoid BAL fluid cells and synergistically induced IFN-gamma production, indicating important cytokines in the Th1 response of sarcoidosis.

Adjuvants, Immunologic↗

PubMed2001

Interleukin-18 enhances the production of interleukin-8 by eosinophils.

Interleukin-18 (IL-18), a proinflammatory cytokine, leads to IFN-gamma production by NK or T cells, induces Th1 differentiation and suppresses IgE synthesis by B cells when acting on responding cells together with IL-12. IL-18 also exhibits biological activities related to allergic inflammation such as histamine or IL-4 release from basophils and accumulation of eosinophils in localized lesions in allergic model mice. In this study, Reverse transcription (RT)-PCR analysis revealed that IL-18 receptor alpha chain mRNA was expressed in both freshly prepared eosinophils and two eosinophilic cell lines (YY-1 and EoL-1 cells). Flow cytometry and RT-PCR analyses revealed that the treatment of YY-1 cells with n-butyric acid promoted cell maturation and caused an enhancement of IL-18 receptor alpha chain expression. IL-18 had little effect on the survival of peripheral eosinophils, but it dose-dependently augmented IL-8 synthesis by YY-1 cells. In addition, IL-18-mediated up-regulation of IL-8 expression in eosinophils from a patient suffering from hyper-eosinophilic syndrome was confirmed. Our findings using peripheral blood eosinophils and eosinophilic cell line suggest the functional importance of IL-18 in the induction of IL-8 and a potential proinflammatory role in allergy.

Butyric Acid↗

PubMed2001

Characterization and tumorigenicity of human ovarian surface epithelial cells immortalized by SV40 large T antigen.

OBJECTIVES: Epithelial ovarian cancers are considered to arise from neoplastic transformation of the ovarian surface epithelium (OSE). However, the earliest events in ovarian carcinogenesis have not been clearly defined because patients are often diagnosed in the advanced stages and useful in vivo and in vitro experimental systems using human OSE cells are lacking. We aimed to improve the availability of experimental models for the study of human ovarian carcinogenesis. METHODS: Subcultured human OSE cells were transfected with SV40 large T antigen. Resulting OSE cell lines were characterized using immunocytochemistry and tested tumorigenicity. RESULTS: Six immortalized OSE cell lines were obtained. All cell lines essentially retained the original morphological features of normal OSE cells and showed higher proliferation rates and saturation density. Although they were all nontumorigenic in athymic mice, OSE2b-2 sv cells, which were selected in soft agar from colonies of an SV40 large T antigen-expressing transfectant, OSE2b sv, produced tumors on the peritoneal surface, mesothelium, and diaphragm and induced ascites after being injected intraperitoneally. Solid tumors also grew when mice were inoculated subcutaneously. The tumor cells were formed in a solid sheet arrangement and no evidence of glandular or squamous differentiation was present. They were weakly immunostained with an antibody against cytokeratin, and intercellular junctions resembling attachment devices were ultrastructurally present between cells. The tumors were histologically diagnosed as undifferentiated carcinomas. CONCLUSIONS: The established cell lines may provide a model system to investigate the mechanisms of cytogenic and molecular changes from normal OSE cells through the various steps of transformation.

Aged↗

PubMed2001

5'-deoxy-5-fluorouridine, medroxyprogestrone acetate and mitoxantrone hydrochloride for advanced or recurrent breast cancer.

BACKGROUND: In treating advanced or recurrent breast cancer, anthracycline-containing chemotherapy is used for palliation and to maintain quality of life. However, there are several drawbacks including therapeutic failure and cardiotoxicity. We evaluated the efficacy and toxicity of combination chemotherapy with 5'-deoxy-5-fluorouridine (5'-DFUR), medroxyprogestrone acetate (MPA) and mitoxantrone hydrochloride (MIT). METHODS: Sixteen patients with advanced or recurrent breast cancer were enrolled. Chemotherapy was given in a 28-day cycle, starting with MIT 10 mg/m2 intravenously on day 1, then oral 5'-DFUR 800 mg and MPA 800 mg daily. Two or more cycles were given. RESULTS: Fifteen patients were assessable for response and toxicity. Thirteen patients had been treated previously with an anthracycline containing regimen and 2 with CMF. There were 2 partial response patients (13.3%) and 1 complete response patient (6.7%). There were 11 patients showing no change (NC) (73.3%), one of whom was a minor responder and 7 with a long period of NC. There was only one with progressive disease patient. The overall response rate was 20.0%. Adverse events occurred in 5 patients (33.3%). Myelosuppression was the most common with 5 patients becoming leukopenic (33.3%). Nausea/vomiting was the second most common side effect, affecting 2 patients (13.3%). CONCLUSION: Given its high efficacy and preservation of QOL, the combination of MIT, 5'-DFUR and MPA can be a 2nd or 3rd line therapy for advanced or recurrent breast cancer, especially for anthracycline-resistant cases.

Adult↗

PubMed2001

Effects of sibutramine on the central dopaminergic system in rodents.

The effects of sibutramine on central dopaminergic system in rats and mice were examined by neurochemical and behavioral pharmacological methods. Dopamine reuptake inhibition by sibutramine in brain synaptosomes was only 4-5 times stronger than those of amitriptyline and dosulepin, which do not exhibit dopamine uptake inhibition in vivo. Single treatment with sibutramine did not alter the brain content of dopamine and DOPAC. However, similar to methamphetamine and pargyline, sibutramine antagonized methyl-4-pheny-1,2,3,6-tetrahydro-pyridine (MPTP) induced dopamine depletion in mouse brain. In forced swimming tests of reserpinized mice, sibutramine shortened the immobilized time, similar to dopaminergic drugs including nomifensine, bupropion (dopamine-reuptake inhibitor), methamphetamine, SKF 38393 (dopamine D1 agonist), quinpirole (dopamine D2 agonist) and apomorphine (dopamine D1/D2 agonist). In addition, sibutramine caused rotational behavior toward the lesioned side in rats with unilateral lesions of the substantia nigra induced by 6-hydroxydopamine. These results suggest that sibutramine exhibits neurochemical and behavioral dopaminomimetic activity in vivo, which is mediated by dopamine reuptake inhibition by the active metabolites of sibutramine.

Journal Article↗

PubMed2001

Comparisons of event-related potentials after repetitive transcranial magnetic stimulation.

Effects of repetitive transcranial magnetic stimulation (rTMS) on the human cognitive process were investigated by examining auditory event-related potentials (ERPs) in 15 healthy subjects. Two rTMS trains were delivered over the left frontal area, with 30 pulses in each train. ERPs were recorded at 14 electrode sites on the scalp using a typical oddball protocol before and after rTMS. Tone stimuli (20% target and 80% standard) were delivered through earphones. Latency and amplitude of N100, P200, N200 and P300 were measured and compared during the study. To observe information flow between two electrode sites, directed coherence (DCOH) was calculated on the ERPs. Our results show that the effect of rTMS differs in the various ERPs components (P < 0.001). The latency of P300 significantly increased after stimulation, and the increase was more obvious in the frontal (18.6 ms) and central (15.8 ms) areas. The latency of P200 decreased in all areas. The amplitude of component N100 in the frontal and central areas decreased after rTMS. DCOH from the central area to the temporal area and DCOH from the parietal area to the temporal area were significantly higher than the DCOH between other areas (P < 0.01), and these properties were not affected by rTMS (P > 0.05). Information flow was driven from the frontal area to the parietal area after stimulation. Our results suggest that rTMS can suppress cognitive activities, showing an inhibitory effect on neurophysiological processes in the human brain. Since the temporal area is located at the terminus of the propagation pathways, it plays important roles in processing information in cognitive activities.

Adult↗

PubMed2001

Expression of monocyte chemoattractant protein-1 in peritoneal endometriotic cells.

It is well known that the number of peritoneal macrophages is increased in patients with pelvic endometriosis. We measured the concentration of monocyte chemoattractant protein-1 (MCP-1) using an enzyme-linked immunosorbent assay (ELISA) in the peritoneal fluid of women with and without endometriosis. The expression of MCP-1 in pelvic endometriotic lesions obtained from the peritoneum was also examined using immunohistochemistry and nonradioactive in situ hybridization. The mean concentration of MCP-1 in the peritoneal fluid was significantly higher in the patients with endometriosis (P<0.05). The most significant elevation, compared with non-endometriosis patients, was found in stage I of the disease (P<0.05). However, no statistically significant difference was found among endometriosis stages I, II, III, and IV. Immunohistochemical staining revealed that MCP-1-positive cells were localized in the glandular epithelium of the endometriotic lesions and in the stromal macrophages distributed in those lesions, but normal peritoneal cells were negative. The in situ hybridization method demonstrated expression of MCP-1 mRNA on the endometriotic glandular epithelium and stromal macrophages. These findings suggest that MCP-1 may be involved in the histogenesis and early development of peritoneal endometriosis.

Ascitic Fluid↗

PubMed2001

The missense Glu298Asp variant of the endothelial nitric oxide synthase gene is strongly associated with placental abruption.

We recently identified a missense variant (Glu298Asp) that lies within exon 7 of the endothelial nitric oxide synthase (eNOS) gene, and that is associated with severe preeclampsia (proteinuric hypertension that develops as a consequence of pregnancy). Maternal hypertension is the most consistently identified factor predisposing to placental abruption. Our objective, therefore, was to analyze the association between the Glu298Asp eNOS gene variant and placental abruption. The study participants included 35 patients with histories of placental abruption and 170 control subjects. Screening for the Glu298Asp eNOS gene variant was carried out by analysis of polymerase chain reaction/restriction fragment length polymorphism. The analyses revealed that the frequency of the Glu298Asp variant (Glu298Asp homozygotes and heterozygotes) was significantly (P<0.001) higher in the placental abruption group (n=14; 40%) than in the control group (n=24; 14%). We conclude that the presence of the Glu298Asp eNOS gene variant could be a marker of increased risk of developing placental abruption.

Abruptio Placentae↗

PubMed2001

Immunohistochemical localization of phospholipase C isozymes in mature and developing gerbil cochlea.

The possibility that phospholipase C contributes to intracellular signaling in the cochlea was investigated by immunostaining for eight different isoforms of the enzyme. In the mature gerbil cochlea, expression of the isozymes varied widely among different cell types. The phospholipase C-beta1 isoform was detected in inner and outer hair cells, and spiral ganglion neurons where it may participate in regulating Ca(2+) flux. The beta3 isozyme was expressed in epithelial cells thought to mediate lateral and medial circulation of potassium. The beta2 isozyme was present in border, inner phalangeal and Hensen cells, the stria vascularis, and suprastrial and supralimbal fibrocytes where it also may be involved in regulating ion transport activities. The phospholipase C-gamma isozymes were expressed in supporting cells, the stria vascularis, and certain fibrocytes where they possibly participate in activating tyrosine kinase and modulating ion conductances. The delta2 isoform was found in pillar, outer sulcus and strial marginal cells as well as spiral ganglion neurons and their radial processes. Documentation of changes in the expression pattern of phospholipase C isoforms during postnatal development and knowledge of their distribution in several positive control tissues provided further data for speculation about the biologic significance of the cochlear reactivity. The results demonstrate a wide diversity of isozyme distribution in the cochlea and suggest that the enzymes affect activities of various cochlear cell types in different ways.

Aging↗

PubMed2001

Developmental expression of monocarboxylate transporter in the gerbil inner ear.

The expression of H+-monocarboxylate cotransporters (MCTs) that facilitate cell uptake of lactate, pyruvate and other monocarboxylates was investigated in the adult and postnatally developing gerbil inner ear. In the mature cochlea, immunoreactive MCT1 was present in marginal cells of the stria vascularis and in type II, suprastrial and limbal fibrocytes. In the adult vestibular system, dark cells and a subpopulation of fibrocytes immediately underlying maculae and cristae stained strongly for MCT1. Satellite cells surrounding mature spiral and vestibular ganglia neurons also expressed MCT1. MCT1 immunoreactivity was present at birth in marginal and dark cells, at 8 days after birth in fibrocytes and at 12 days after birth in satellite cells, and coincided precisely with the developmental expression of Na,K-ATPase in these sites. The coexpression of MCT1 and Na,K-ATPase in these cell types points to MCT1 as an important source of energy to drive inner ear Na,K-ATPase activity. In the adult inner ear, MCT2 was detectable only in tectal cells of the cochlea and supporting cells of the crista ampullaris. Immunostaining was first observed at 16 days after birth in tectal and at 20 days after birth in supporting cells, and at the same time immunoreactive aquaporin 4 appeared in these cells. The coexpression of MCT2 and aquaporin 4 suggests a possible role for MCT2 in regulating transcellular water movement. Because MCT2 facilitates the transport of acidic intermediates, its biological significance also could relate to modulation of cell pH and volume. Maintenance of the inner ear's unique ion and fluid gradients is essential to normal hearing and balance and requires the expenditure of large amounts of energy. The cellular distribution of MCT1 and MCT2 points to their participation in generating these electrochemical gradients and their potential involvement in sensory deficits associated with various inner ear disorders.

Aging↗

PubMed2001

Effect of neonatal treatment with monosodium glutamate on dopaminergic and L-DOPA-ergic neurons of the medial basal hypothalamus and on prolactin and MSH secretion of rats.

The effect of neonatal treatment with monosodium L-glutamate (MSG) on the dopaminergic systems of the medial basal hypothalamus has been investigated using tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC) immunocytochemistry. Changes in plasma levels of prolactin (PRL) and alpha-melanocyte-stimulating hormone (MSH) have also been determined in intact and in MSG-treated rats after inhibition of TH by alpha-methyl-p-tyrosine (alpha-MpT) or without inhibition of enzyme activity. Monosodium glutamate resulted in a 40% reduction in the number of TH immunopositive tuberoinfundibular neurons, but no change in the number of AADC-positive tuberoinfundibular nerve cells, indicating that this reduction has occurred mainly in TH-positive but AADC-negative elements, i.e., in L-DOPA-ergic neurons. In contrast, MSG did not cause changes in the number of TH and AADC immunoreactive neurons of the periventriculohypophysial and tuberohypophysial dopaminergic systems, and it did not influence basal plasma PRL levels. alpha-methyl-p-tyrosine has increased plasma PRL concentrations in both control and MSG-treated rats of both sexes, but significantly higher responses were detected in females. None of the treatments had any effect on plasma MSH level. These findings suggest that MSG affects primarily L-DOPA-ergic neurons located in the ventrolateral part of the arcuate nucleus, but not dopaminergic neurons situated in the dorsomedial part of the arcuate nucleus; neither PRL nor MSH secretion is altered by MSG; a significant sex difference exists in the pituitary PRL response to inhibition of TH, and this response is not affected by MSG.

Animals↗

PubMed2001

Fatigue in ambulatory patients with advanced lung cancer: prevalence, correlated factors, and screening.

Although it has been indicated that patients with lung cancer experience higher level of fatigue than patients with other cancers, few published studies have focused on the characteristics of this fatigue and how it interferes with daily activities. The purpose of this study was to clarify fatigue prevalence and the factors correlated with fatigue, and to develop a screening method for fatigue in patients with advanced lung cancer. One hundred fifty-seven patients completed two fatigue scales (Cancer Fatigue Scale [CFS], and Fatigue Numerical Scale [FNS]) plus other measures, along with a self-administered questionnaire asking whether fatigue had interfered with any of 7 areas of daily activities. Fifty-nine percent of patients had experienced clinical fatigue, which was defined as fatigue that interfered with any daily activities. Logistic regression analysis demonstrated that symptoms of dyspnea on walking, appetite loss, and depression were significant correlated factors. Both CFS and FNS were found to have sufficient sensitivity and specificity for use as a screening tool. The results indicated that fatigue is a frequent and important symptom, which is associated with both physical and psychological distress in this population. The CFS and FNS were confirmed to have sufficient screening ability.

Adult↗

PubMed2001

Transcriptional regulation in lymphocytes.

Lymphocytes have been used to investigate many cellular processes, including lineage commitment, differentiation, proliferation and apoptosis. The transcription factors that mediate these processes are often expressed broadly in many cell types. The emerging theme is one of cell-type-specific regulation, affecting not only the functional activation of transcription factors but also their access to appropriate regions of DNA.

Animals↗

PubMed2001

Solution structure of a telomeric DNA complex of human TRF1.

BACKGROUND: Mammalian telomeres consist of long tandem arrays of double-stranded TTAGGG sequence motif packaged by TRF1 and TRF2. In contrast to the DNA binding domain of c-Myb, which consists of three imperfect tandem repeats, DNA binding domains of both TRF1 and TRF2 contain only a single Myb repeat. In a DNA complex of c-Myb, both the second and third repeats are closely packed in the major groove of DNA and recognize a specific base sequence cooperatively. RESULTS: The structure of the DNA binding domain of human TRF1 bound to telomeric DNA has been determined by NMR. It consists of three helices, whose architecture is very close to that of three repeats of the c-Myb DNA binding domain. Only the single Myb domain of TRF1 is sufficient for the sequence-specific recognition. The third helix of TRF1 recognizes the TAGGG part in the major groove, and the N-terminal arm interacts with the TT part in the minor groove. CONCLUSIONS: The DNA binding domain of TRF1 can specifically and fully recognize the AGGGTT sequence. It is likely that, in the dimer of TRF1, two DNA binding domains can bind independently in tandem arrays to two binding sites of telomeric DNA that is composed of the repeated AGGGTT motif. Although TRF2 plays an important role in the t loop formation that protects the ends of telomeres, it is likely that the binding mode of TRF2 to double-stranded telomeric DNA is almost identical to that of TRF1.

Amino Acid Motifs↗

PubMed2001

Interleukin-18 is a unique cytokine that stimulates both Th1 and Th2 responses depending on its cytokine milieu.

IL-18 is a potent proinflammatory cytokine able to induce IFNgamma, GM-CSF, TNFalpha and IL-1 in immunocompetent cells, to activate killing by lymphocytes, and to up-regulate the expression of certain chemokine receptors. IL-18 is also essential to host defences against severe infections. In particular, the clearance of intracellular bacteria, fungi and protozoa requires the induction of host-derived IFNgamma, which evokes effector molecules such as nitric oxide. Also, IL-18 plays a part in the clearance of viruses, partly by the induction of cytotoxic T cells, and the expulsion of viruses is impaired in IL-18-deficient mice. IL-18 also enhances tumour rejection by its potent capacity to augment the cytotoxic activity of NK and T cells in vivo. In contrast, recent studies also demonstrate a convincing role for IL-18 in atopic responses, including atopic asthma. IL-18 induces naive T cells to develop into Th2 cells. Moreover, IL-18 also induces IL-13 and/or IL-4 production by NK cells, mast cells and basophils. Therefore, IL-18 should be seen as a unique cytokine that enhances innate immunity and both Th1- and Th2-driven immune responses.

Animals↗

PubMed2001

Peplomycin-induced apoptosis in oral squamous carcinoma cells depends on bleomycin sensitivity.

Oral squamous carcinoma cell line SSCKN cells were shown to be highly sensitive to bleomycin, whereas SCCTF cells were minimally sensitive to this reagent. To determine whether the anticancer drug resistance to oral squamous carcinoma cells could be related to the degree of the drug-induced apoptosis, we examined the effects of peplomycin on induction of apoptosis in these cells. After reaching subconfluence, SCCKN and SCCTF cells were exposed to various concentrations of peplomycin. Peplomycin caused cytotoxicity in both SCCKN and SCCTF cells in a dose-dependent fashion with the maximal effect at concentrations of 1 and 10 microM, respectively, as determined by phase-contrast microscopy and WST-1 cell viability assay. By using the Hoechst 33342 staining, we observed marked nuclear condensation and fragmentation of chromatin in SCCKN cells treated with 1 microM peplomycin. However, SCCTF cells treated with 1 microM peplomycin showed neither nuclear condensation nor fragmentation. DNA ladder formation was also detected in both cell lines by treatment with peplomycin. The induced DNA ladder formation in SCCKN and SCCTF cells was dose-dependent, with the maximal effect at concentrations of 5 and 50 microM, respectively. Bleomycin also induced DNA ladder formation in SCCKN and SCCTF cells with different sensitivities. Mitomycin C induced DNA laddering in both SCCKN and SCCTF cells; however, the intensity of DNA ladder formation was almost the same in both cell lines. The present results indicate that peplomycin-induced apoptosis in oral squamous carcinoma cell lines depends on the sensitivity of these cells to bleomycin.

Antibiotics, Antineoplastic↗

PubMed2001

Effects of high frequency repetitive transcranial magnetic stimulation on P(300) event-related potentials.

OBJECTIVE: Auditory event-related potentials (P(300)-ERPs) were analyzed before and after repetitive transcranial magnetic stimulation (rTMS). METHODS: Two rTMS trains (10 Hz, 3 s, 100% motor threshold and 5 min interval) were delivered over the left frontal area in healthy subjects. P(300)-ERPs were recorded at 14 electrode sites on the scalp using a typical oddball paradigm before and after rTMS. The latencies and amplitudes of N(100), P(200), N(200) and P(300) were measured and compared. The directed coherence (DCOH) was estimated to demonstrate information flow between different cortical areas. RESULTS: rTMS significantly influenced P(300)-ERPs. The effects differed on the different components (P<0.001). The latency of P(300) significantly increased after stimulation, which was more obvious in the frontal and central areas. The changes in P(300) amplitude were not significant (P>0.05). The DCOH from the frontal, central, parietal and occipital areas to the temporal area was significantly higher than the DCOH from the temporal area to the former 4 areas (P<0.01). CONCLUSIONS: rTMS with the present parameters can affect P(300)-ERPs, leading to a delayed P(300) component and changes in information connections around the stimulated site. Our data suggest that rTMS may postpone neuronal activities related to cognitive processing.

Adult↗

PubMed2001

Antifeedant rings B and D opened limonoids from Khaya senegalensis.

Three new rings B and D opened limonoids, two mexicanolides named khayanone (1) and 2-hydroxyseneganolide (2) and one rearranged phragmalin limonoid of 1-O-acetylkhayanolide A (3), were isolated together with six known B,D-seco compounds from the acetone extract of the stem bark of Khaya senegalensis. Structures of new compounds were elucidated by spectroscopic means, and the absolute stereochemistry of 1 was established by CD study of the dibenzoate derivative. The insect antifeedant and antiviral activities of the new compounds were also determined.

Animals↗