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Biomedical subjects

M Minami

Publications and source records attributed to M Minami.

At least 253 records · Page 14Linked to original sources

Intracerebroventricular injection of isoproterenol produces its analgesic effect through interleukin-1beta production.

The effects of isoproterenol, a beta-adrenoceptor agonist, on the production of interleukin-1beta in the brain and on mechanical nociception were examined in rats. Intracerebroventricular (i.c.v.) injection of isoproterenol at the dose of 3 microg/rat markedly induced interleukin-1beta mRNA in the molecular layer of the hippocampus, medial preoptic area, paraventricular thalamic nucleus, paraventricular hypothalamic nucleus, ventromedial hypothalamic nucleus, dorsomedial hypothalamic nucleus and central gray 1 h after injection. In these regions, interleukin-1beta mRNA was expressed mainly in the glial cells. The thresholds to the mechanical stimulation to the hind paw were elevated by i.c.v. administration of isoproterenol (1 to 10 microg/rat). When isoproterenol was given at the dose of 3 microg/rat, the analgesic effect showed two peaks. The first peak was observed at 60 min after injection and the second was observed at 180 min. The second phase of analgesia was antagonized by coadministration of interleukin-1 receptor antagonist. These results suggest that isoproterenol produces an analgesic effect, at least in part, through the induction of interleukin-1beta expression in the brain.

Analgesics↗

DX-8951f, a water-soluble camptothecin analog, exhibits potent antitumor activity against a human lung cancer cell line and its SN-38-resistant variant.

We previously reported that DX-8951f, a novel water-soluble camptothecin analog, significantly inhibits the growth of various human and murine tumors in vitro and in vivo. The antitumor effects and topoisomerase I inhibitory activity of DX-8951f are stronger than those of other current camptothecin analogs. In this study, we established an SN-38-resistant cell line, PC-6/SN2-5, from the human oat cell carcinoma PC-6 cell line by a stepwise selection system, investigated the mechanism of resistance of this cell line and then compared the antitumor activity of camptothecin analogs against the cell line. PC-6/SN2-5 cells were resistant to SN-38 (32-fold) and SK&F 104864 (topotecan; 14-fold), but barely resistant to CPT-11 (3-fold) and DX-8951f (2-fold). Topoisomerase I protein levels and topoisomerase I activities of parental cells were similar to those of resistant cells. Determination of the cellular drug concentration by either flow cytometric analysis or the high-performance liquid chromatography method confirmed that the cellular accumulation of SN-38 and topotecan was significantly reduced in PC-6/SN2-5 cells, whereas that of DX-8951f was only slightly reduced. Furthermore, DX-8951f stabilized the cleavable complex formations in intact PC-6/SN2-5 cells as well as in parental cells, but SN-38 and topotecan did not in the resistant cells. Our data suggest that PC-6/SN2-5 cells may have acquired resistance to camptothecin analogs by a decrease in intracellular drug accumulation and that DX-8951f may have the potency to overcome such a type of resistance mechanism induced by camptothecin compounds.

Antineoplastic Agents↗

Method for the analysis of the methylphosphonic acid metabolites of sarin and its ethanol-substituted analogue in urine as applied to the victims of the Tokyo sarin disaster.

An analysis method for the methylphosphonic acid metabolites of sarin in urine using trimethylsilyl derivatization and flame photometric detection is described in this report. Authentic reference standards of isopropyl methylphosphonic acid (IMPA) and ethyl methylphosphonic acid (EMPA) as well as methylphosphonic acid were employed to estimate the concentration in human urine. A sample pretreatment procedure was developed for urine using a column of cation-loaded ion-exchange resins (Ag+ -, Ba2+ - or H+ -Dowex) and adjusting the pH of the eluate from the column to 3.75-3.85 improved recovery of the target compounds. The eluate was evaporated to dryness under vacuum prior to trimethylsilylation, to remove water and any hydroxy- or amino-carrying volatile substances. The sarin metabolites, because of their low volatility, were concentrated and could be derivatized for analysis. The use of synthesized authentic sarin and ethylsarin metabolites, i.e., IMPA and EMPA, made it possible to establish the necessary sample pretreatment procedures for derivatization and gas chromatography-flame photometric detection (GC-FPD) analysis. The detection limits were 0.025 ppm both for EMPA and [MPA, and 0.625 microM for MPA, respectively. This method can be useful for estimating the exposure level to sarin by assaying the metabolites in urine and it is applicable to a large numbers of samples.

Chemical Warfare Agents↗

Induction of macrophage inflammatory protein MIP-1alpha mRNA on glial cells after focal cerebral ischemia in the rat.

The distribution and cell source of macrophage inflammatory protein-1alpha (MIP-1alpha) mRNA induced by transient and permanent middle cerebral artery occlusion (MCAO) were investigated by a double in situ hybridization technique. The distribution and time course of the induction of MIP-1alpha mRNA were similar in the two MCAO models. MIP-1alpha mRNA was not detected in the sham-operated rat brain. MIP-1alpha mRNA was induced by MCAO with the peak of expression at 4-6 h after the onset of occlusion, and the signals of MIP-1alpha mRNA were observed in the ischemic core region at an earlier time point, and thereafter intensely in the penumbra of the ischemic area. The signals of MIP-1alpha mRNA were evident on Mac-1alpha mRNA-positive cells, but not on glial fibrillary acidic protein (GFAP) mRNA-positive cells, indicating that MIP-1alpha mRNA was induced in microglia/macrophages of the rat brain after focal cerebral ischemia.

Animals↗

The amino acid residues immediately carboxyl-terminal to the tyrosine phosphorylation site contribute to interleukin 6-specific activation of signal transducer and activator of transcription 3.

Signal transducers and activators of transcription (Stat) proteins play an important role in signaling through a variety of cytokine and growth factor receptors. Each of the Stat proteins is activated in a ligand-specific manner. Only the Src homology 2 (SH2) domains of Stat1 and Stat2 are critical for the ligand-specific activation of interferon signaling. In this study we determined the domains in Stat3 protein that contribute to interleukin 6 (IL-6)-specific phosphorylation. Based on evidence that Stat3, but not Stat1, is activated in the presence of low levels of IL-6 and soluble IL-6 receptor, we constructed various swap mutants between Stat3 and Stat1 and examined their response to IL-6 after their transient expression into COS7 cells. The region upstream of the SH2 domain was exchangeable between Stat1 and Stat3, whereas the region carboxyl-terminal to the SH2 domain of Stat3 was critical to phosphorylation by IL-6. However, unlike Stat1 and Stat2 in interferon signaling, the swap mutant in which 5 amino acid residues just carboxyl-terminal to the tyrosine phosphorylation site (Tyr705) in Stat3 was replaced by the corresponding region derived from Stat1 was not phosphorylated in response to IL-6. Substituting 1 amino acid (Lys709) at position +4 relative to Tyr705 abolished the tyrosine phosporylation of Stat3 in response to IL-6. Co-immunoprecipitation experiments demonstrated that these mutants were associated with gp130 at an extent similar to wild-type Stat3. Taken together, these results show that the amino acid residues immediately carboxyl-terminal to the tyrosine phosphorylation site are involved in IL-6-specific activation of Stat3.

Acute-Phase Proteins↗

Ectopic Breast Caner: Two Case Reports and Review of the Japanese Literature.

Two cases of carcinoma involving ectopic breast tissue are reported, along with a review of the Japanese literature. A total of 65 cases of ectopic breast cancer have been reported; 59 of which occurred in the axilla. Total mastectomy with axillary dissection was performed in 29 cases, and tumor excision with or without nodal dissection was done in 30 cases. Outcome was known in 33 cases, and 5 cases had recurred at the time of this writing. Although the prognosis of ectopic breast cancer was difficult to establish with the limited follow-up data, all the 5 cases in our series with recurrence had axillary lymph node metastases at the time of surgery. Therefore, the complete excision of ectopic breast tissue with nodal dissection, and subsequent chemoendocrine therapy, especially in node-positive patients, is recommended as the treatment of choice.

Journal Article↗

Antiemetic effects of N-3389, a newly synthesized 5-HT3 and 5-HT4 receptor antagonist, in ferrets.

The antiemetic activity of N-3389 (endo-3,9-dimethyl-3,9-diazabicyclo[3,3,1]non-7-yl-1 H-indazole-3-carboxamide dihydrochloride), a new 5-HT3 and 5-HT4 receptor antagonist, against cisplatin-, cyclophosphamide- and copper sulfate-induced emesis was investigated using ferrets. We also examined the effects of these agents on abdominal afferent vagus nerve activity in anesthetized ferrets. Both intraperitoneal (0.1-1.0 mg/kg) and oral (0.1-1.0 mg/kg) administration of N-3389 produced dose-dependent antiemetic effects. The time-course of cisplatin (10 mg/kg, i.p.)-induced emesis in another group of ferrets paralleled the increase in abdominal afferent vagus nerve activity induced by cisplatin (10 mg/kg, i.p.) and was inhibited by pretreatment with N-3389 (1.0 mg/kg, i.v.). Furthermore, the cisplatin (10 mg/kg, i.p.)-induced increase in abdominal afferent vagus nerve activity was markedly reduced by an additional injection of N-3389 (0.1-1.0 mg/kg, i.v.) in a dose-dependent manner. The antiemetic effects exhibited by N-3389 are probably due to the inhibition of 5-HT3 and 5-HT4 receptors on the abdominal afferent vagus nerves.

5-Methoxytryptamine↗

Analysis of initial attachment of B cells to endothelial cells under flow conditions.

This study examined the adhesive interactions of peripheral blood B cells with TNF-alpha-activated endothelial monolayers, and analyzed the roles of E-selectin, P-selectin, or VCAM-1 molecules expressed on activated HUVEC. B cell interaction occurred on activated HUVEC, but not on resting HUVEC under flow conditions. The majority of peripheral blood B cells expressed P-selectin glycoprotein ligand-1 and alpha4 integrin. However, the expression of cutaneous lymphocyte Ag on B cells was low. Under flow conditions, B cells could bind to P-selectin-coated tubes and VCAM-1-transfected Chinese hamster ovary cells. In contrast, B cells could not bind to E-selectin-coated tubes. Adhesion activity of B cells to P-selectin-coated tubes was weaker than that of T cells. Furthermore, adhesion activity of B cells to VCAM-1-transfected Chinese hamster ovary cells was similar to that of T cells. Treatment of activated HUVEC with anti-VCAM-1 mAb reduced interaction of B cells under flow conditions. However, the treatment of activated HUVEC with anti-P-selectin mAb did not reduce interaction. These data indicated that the interaction of VCAM-1 with alpha4 integrin plays a major role in an initial attachment of B cells to endothelial monolayers under flow conditions.

Animals↗

Granulocyte colony-stimulating factor and interleukin-6-producing lung cancer cell line, LCAM.

BACKGROUND AND OBJECTIVES: We describe a case of granulocyte colony-stimulating factor (GCSF) and interleukin-6 (IL-6)-producing lung cancer. METHODS: A 53-year-old man underwent left upper lobectomy under diagnosis of lung cancer. The tumor obtained by a preoperative biopsy was analyzed. RESULTS: Preoperative data showed leukocytosis with left-shift of leukocytic morphology and thrombocytosis and an elevated serum GCSF level. Histological examination revealed poorly differentiated adenocarcinoma. A cell line, named LCAM, was established from the tumor and the cytokines in the culture medium were measured by enzyme immunoassay. GCSF and IL-6 were produced in large amounts by LCAM, but granulocyte-macrophage colony-stimulating factor (GMCSF) and interleukin-3 (IL-3) were not. A proportion of LCAM expressed GCSF receptor on the cell surface, but IL-6 receptor could not be detected. LCAM proliferation was inhibited in the culture with antihuman GCSF antibody in a dose-dependent manner. CONCLUSIONS: We suggest that LCAM proliferation is positively regulated by GCSF.

Granulocyte Colony-Stimulating Factor↗

Epitope selection in major histocompatibility complex class I-mediated pathway is affected by the intracellular localization of an antigen.

We analyzed the mode of antigen presentation of an endogenous antigen localized in the cytoplasm or in the mitochondria. Pseudomonas aeruginosa PAO leucine-, isoleucine-, valine-binding protein (LIVAT-BP) encoded by the braC gene was used as a model antigen. Using mouse BALB/3T3 cells, we established two LIVAT-BP transfectants by transfection of a plasmid harboring the intact braC or braC gene fused with the mitochondrial transport signal derived from the yeast COXIV gene. One of the resulting transfectants, BC-15, expressed LIVAT-BP in the cytoplasm, while YZ-710 cells expressed LIVAT-BP in the mitochondria. The splenic effector cells derived from BALB/c mice primed with BC-15 cells exhibited cytotoxic T lymphocyte (CTL) activity against BC-15 cells, but not against YZ-710 cells, whereas splenic effector cells primed with YZ-710 cells exhibited CTL activity against YZ-710 cells, but not against BC-15 cells. Neither group of splenic effector cells showed CTL activity against parental BALB/3T3 cells. These CTL belonged to the CD8+ alphabeta T cell subset. Furthermore, we observed that the CTL activity against t BC-15 cells or YZ-710 cells was blocked with anti-H2-K(d) mAb, but not with anti-H2-D(d) or H2-L(d) mAb. The CTL against BC-15 or YZ-710 cells could kill parental BALB/3T3 cells in the presence of peptides produced by alkali lysis of the LIVAT-BP, suggesting that these CTL indeed recognized the peptide(s) derived from LIVAT-BP. We determined that the epitope for the CTL against BC-15 cells was QYGEGIATEV, corresponding to residues 162-171, and that the epitope recognized by the CTL against YZ-710 cells was GYKLIFRTI, corresponding to residues 123-131 of LIVAT-BP, respectively. Thus, we show here that epitope selection for MHC class I expression is affected by the intracellular localization of the antigenic protein.

3T3 Cells↗

Experimental bronchiolitis obliterans induced by in vivo HVJ-liposome-mediated endothelin-1 gene transfer.

BACKGROUND: Bronchiolitis obliterans (OB) is a lesion that results when injury to small conducting airways is repaired by a proliferation of fibrous granulation tissue. Bronchiolitis obliterans has emerged as a main cause of morbidity and mortality in the setting of lung and heart-lung transplantation. Endothelin-1 (ET-1), initially discovered as a vasoconstrictive peptide, has a mitogenic activity on vascular smooth cells and airway epithelial cells. Overproduction of endothelin has been reported in patients with OB or chronic rejection after lung transplantation. It is still undetermined whether locally overexpressed ET-1 has a potential impact in the pathogenesis of OB. METHODS: We locally overexpressed ET-1 using ultraviolet irradiation-inactivated hemagglutinating virus of Japan (HVJ)-liposome-mediated in vivo gene transfer. Plasmid DNA of prepro-ET-1 and high mobility group 1 protein were coencapsulated in liposomes, and were introduced into airway epithelial cells by HVJ-mediated membrane fusion. Control animals received instillation of HVJ-liposome with an empty expression cassette. To confirm the efficiency of transfection, HVJ liposome with beta-galactosidase gene was introduced. The expression of ET-1 and beta-galactosidase was assessed by immunohistochemistry. RESULTS: Bronchial epithelium alveolar cells and alveolar macrophage were stained blue (X-Gal) 1 week after in vivo gene transfer of beta-galactosidase gene, indicating beta-gal activity. In animals 1 to 2 weeks after in vivo transfection of prepro-ET-1 gene, hyperplastic connective tissue plaque was seen in the alveolar duct and small conducting airway, indicating histologically distinctive bronchiolitis obliterans. Strong ET-1-like immunoactivities were seen in the airway epithelial, hyperplastic connective tissue, and alveolar cells. No histopathologic changes were seen in the control animals. CONCLUSIONS: These results suggested that ET-1 may play an important role in the pathogenesis of OB. The effective pharmacologic antagonist or inhibitor may possibly control the progression of disease in patients of OB.

Animals↗

Increased nitric oxide levels in exhaled air of rat lung allografts.

In organ transplantation nitric oxide has been reported to be involved in allograft rejection. We examined in a rat lung transplantation model whether nitric oxide is overproduced in acute rejection and can be detected in exhaled air. Thirteen rat right lung transplants were separated into three groups: group 1 (n = 5), untreated allografts (Brown-Norway [RT1n] to Lewis [RT1l]); group 2 (n = 4), cyclosporine-treated allografts; and group 3 (n = 4), isografts (Lewis to Lewis). We examined exhaled nitric oxide levels with a chemiluminescence analyzer and chest roentgenograms on days 2 through 5. Histologic samples were obtained on days 3 and 5. On day 5, the recipients were killed and we measured exhaled nitric oxide from the right and left lungs separately. Blood samples were also obtained for measurement of serum nitrite/nitrate. The exhaled nitric oxide level in untreated allografts increased significantly from day 5 (63.9 +/- 39.2 ppb, p = 0.0095) and was significantly higher than that in treated allografts (9.1 +/- 1.6 ppb) (p = 0.0085) and isografts (6.9 +/- 0.5 ppb) (p = 0.0068). The nitric oxide level in untreated allografts (826.5 +/- 416.1 ppb) was 75 times as high as that from the contralateral normal left lungs (11.2 +/- 2.6 ppb) (p = 0.0118). The level of exhaled nitric oxide correlated significantly with the histologic rejection grade (p = 0.0001). There was no significant difference in the serum nitrite/nitrate levels between allografts and isografts. These data suggest that increased exhaled nitric oxide levels might reflect acute rejection in lung transplants.

Animals↗

Improvement of erythrocyte deformability by cholesterol-lowering therapy with pravastatin in hypercholesterolemic patients.

Erythrocyte deformation is an important regulatory factor of the microcirculation. The present study was designed to examine whether erythrocyte deformability is altered in hypercholesterolemic patients and, if so, whether cholesterol-lowering therapy affects this parameter in these patients. The erythrocyte deformability of 37 hypercholesterolemic patients was evaluated before and after 1 year of therapy with pravastatin, an inhibitor of hepatic hydroxymethyl glutaryl coenzyme A reductase, under various shear stresses (4.7, 9.5, 23.6, 47.3, 118.1, and 236.2 dyne/cm2) using laser diffractometry. At study entry, erythrocyte deformability under 4.7 and 9.5 dyne/cm2 shear stress, which is actually observed in human vessels, was reduced compared with that in 20 age-matched normocholesterolemic subjects and was inversely correlated with serum cholesterol and low-density lipoprotein (LDL) cholesterol. Pravastatin therapy for 1 year, which reduced serum cholesterol from 288 +/- 28 to 223 +/- 20 mg/dL, significantly improved erythrocyte deformability by approximately 20%. There was a significant relation between the improvement of erythrocyte deformability and the reduction of serum cholesterol or LDL cholesterol. The results suggest that erythrocyte deformability is reduced in hypercholesterolemic patients, and that long-term cholesterol-lowering therapy can improve reduced erythrocyte deformability, which may contribute to the improvement of organ perfusion.

Adult↗

Renoprotective effects of a combined endothelin type A/type B receptor antagonist in experimental malignant hypertension.

We previously showed that plasma endothelin-1 (ET-1) concentration was increased in deoxycorticosterone acetate (DOCA)-salt-induced malignant hypertension in spontaneously hypertensive rats (SHR). In contrast, in normal SHR, this value is similar to that seen in Wistar-Kyoto (WKY) rats. The purpose of this study was to examine the effects of the new combined ET type A/type B (ETA/B) receptor antagonist, TAK-044, on the development of hypertension in this model of malignant hypertension. TAK-044 10 mg/kg, which effectively blocks both ETA and ETB receptors, was administered intraperitoneally once per day for 4 weeks in DOCA-salt SHR, and the effects on ET-1 and other parameters were compared with the same values in untreated WKY rats, untreated DOCA-salt SHR, and hydralazine-treated DOCA-salt SHR. DOCA-salt caused marked increases in blood pressure, blood urea nitrogen (BUN), serum creatinine, and plasma ET-1 concentrations in SHR. Both TAK-044 and hydralazine significantly suppressed the increase in blood pressure in DOCA-salt SHR to the same extent. Both treatments also suppressed the increase in BUN and serum creatinine, but this attenuation was less marked with hydralazine than with TAK-044. Neither TAK-044 nor hydralazine affected plasma ET-1 concentration in this model. TAK-044 significantly reduced kidney weight in DOCA-salt SHR, whereas the decrease seen with hydralazine was less marked. Prevention of DOCA-salt-induced renal structural injury (mesangial hypercellularity, glomerular sclerotic changes, and tubulointerstitial damage) in this model was clearly greater with TAK-044 treatment than with hydralazine treatment. These results suggest that endogenous ET-1 may, at least in part, contribute to renal functional and structural damage in malignant DOCA-salt SHR. Our results raise the possibility of renoprotective effects of ETA/B receptor blockers in certain forms of malignant hypertension.

Animals↗

Dietary docosahexaenoic acid increases cerebral acetylcholine levels and improves passive avoidance performance in stroke-prone spontaneously hypertensive rats.

We have recently shown that inferior performance in passive avoidance task is accompanied with decreased hippocampal choline (Ch) in stroke-prone spontaneously hypertensive rats (SHRSP) compared with normotensive control Wistar-Kyoto rats (WKY). We also reported that dietary docosahexaenoic acid (DHA) suppresses the development of hypertension and stroke-related behavioral changes, resulting in the prolongation of the life span of SHRSP. In this study, we examined the effect of dietary DHA on the cerebral acetylcholine (ACh) levels and learning performance in passive avoidance tasks in SHRSP. The arachidonic acid decreased and the DHA increased in plasma lipids dose dependently with dietary DHA treatments, which decreased the systolic blood pressure in SHRSP. Dietary DHA significantly restored the significantly inferior learning performance in passive avoidance response observed in control SHRSP (DHA 0%). Furthermore, the hippocampal ACh levels were correlated positively with the total response latency in passive avoidance tasks. These results suggest that cholinergic dysfunction in the brain of control SHRSP is responsible, at least in part, for the impaired learning ability and the dietary DHA ameliorates this performance failure.

Acetylcholine↗

Predominance of type 2 cytokine-producing CD4+ and CD8+ cells in patients with atopic dermatitis.

BACKGROUND: Recently, increased IL-4 and decreased interferon-gamma (IFN-gamma) production in peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis have been reported by several groups. They measured the total amount of each cytokine in culture supernatants in their studies. These studies suggested a predominance of type 2 cytokine-producing cells in atopic dermatitis. However, it is still unclear whether the cytokine imbalance is the result of an imbalance of specific T-cell subsets or of dysregulation of the cytokine-producing ability in T-cell subsets. Here, we examined frequencies of IL-4-, IFN-gamma-, or IL-2-producing CD4+ cells and CD8+ cells in PBMCs from patients with atopic dermatitis at a single cell level by using flow cytometry. METHODS: PBMCs from 45 patients with atopic dermatitis and 24 healthy control subjects were stimulated with immobilized anti-CD3 monoclonal antibody for 6 hours in the presence of monensin. Cells were fixed, made permeable, and stained for intracellular cytokines in combination with staining for cell surface markers CD4 and CD8. RESULTS: The frequency of IL-4-producing CD4+ cells and CD8+ cells from patients with atopic dermatitis was significantly higher (p < 0.001) than that from healthy control subjects. In contrast, the frequency of IFN-gamma-producing CD4+ cells and CD8+ cells was significantly decreased (p < 0.01) in the patients with atopic dermatitis. The frequency of IL-2-producing cells from patients with atopic dermatitis was comparable to that from healthy control subjects. CONCLUSION: Our findings indicate that frequencies of type 2 cytokine-producing cells, not only among CD4+ cells but also among CD8+ cells, were significantly higher in patients with atopic dermatitis than in healthy control subjects.

Adolescent↗

Effects of dietary docosahexaenoic acid on survival time and stroke-related behavior in stroke-prone spontaneously hypertensive rats.

1. Dietary docosahexaenoic acid (DHA) suppressed the age-dependent increase in systolic blood pressure and prolonged the average survival time of stroke-prone spontaneously hypertensive rats (SHRSP). 2. Dietary DHA (1% and 5% in diets) altered the circadian rhythm of SHRSP, causing significant increases in ambulatory activity during the dark period. At the onset of stroke, desynchronization with light and dark phases and new biological rhythms were noted in all of the control SHRSP (DHA 0%). DHA treated SHRSP did not show such behavioral changes. 3. These effects were accompanied by the increase of DHA and the decrease of AA levels in plasma and brain cortex. 4. It was concluded that dietary DHA suppresses the development of hypertension and stroke-related behavioral changes, resulting in prolongation of the SHRSP's life span.

Aging↗