Experimental conditions and protein markers for redifferentiation of human coronary artery smooth muscle cells

A phenotype switch from contractile type to proliferative type of arterial smooth muscle cells is known as dedifferentiation, but to the best of our knowledge, little is known about redifferentiation of coronary artery smooth muscle cells. The purpose of the present study was to determine in vitro culture conditions for inducing redifferentiation of coronary artery smooth muscle cells. In addition, the present study aimed to determine protein markers for detection of redifferentiated arterial smooth muscle cells. Human coronary artery smooth muscle cells (HCASMCs) were cultured in the presence or absence of growth factors, including epidermal growth factor, fibroblast growth factor-B and insulin. Protein expression and migration activity of HCASMCs were evaluated using western blotting and migration assay, respectively. In HCASMCs 5 days after 100% confluency, expression levels of α-smooth muscle actin (α-SMA), calponin, caldesmon and SM22α were significantly increased, while expression levels of proliferation cell nuclear antigen (PCNA) and S100A4 and migration activity were significantly decreased, compared with the corresponding levels just after reaching 100% confluency, indicating that redifferentiation occurred. Redifferentiation was also induced in a low-density culture of HCASMCs in the medium without growth factors. When the culture medium for confluent cells was replaced daily with fresh medium, the expression levels of α-SMA, caldesmon, SM22α, PCNA and S100A4 and migration activity were not significantly different but the calponin expression was significantly increased compared with the levels in dedifferentiated cells just after reaching 100% confluency. Thus, redifferentiation was induced in HCASMCs by deprivation of growth factors from culture medium. The results suggested that α-SMA, caldesmon and SM22α, but not calponin, are markers of redifferentiation of HCASMCs.

Fabrication and BSA adsorption/desorption properties of titania/silica composite films modified with silane coupling agents

In this study, we successfully prepared titania/silica composite films modified with silane coupling agents having amino groups and investigated their bovine serum albumin (BSA) adsorption/desorption behavior under light irradiation. XRD patterns and ATR/FT-IR spectra of the films revealed the formation of titania/silica composite films modified with silane coupling agents. In these films, the adsorption and desorption of BSA could be controlled by light irradiation, through the locally photoinduced superhydrophilic titania surface.

Hydrogen nanobubble at normal hydrogen electrode

Electrochemically formed hydrogen nanobubbles at a platinum rotating disk electrode (RDE) were detected by re-oxidation charge. The dissolution time course of the hydrogen nanobubbles was measured by AFM tapping topography under open-circuit conditions at stationary platinum and gold single-crystal electrodes. The bubble dissolution at platinum was much faster than that at gold because two types of diffusion, bulk and surface diffusion, proceeded at the platinum surface, whereas surface diffusion was prohibited at the gold electrode. These findings indicated that the electrochemical reaction of normal hydrogen electrode partly proceeded heterogeneously on the three-phase boundary around the hydrogen nanobubble.

Hydrogen nanobubble at normal hydrogen electrode

Electrochemically formed hydrogen nanobubbles at a platinum rotating disk electrode (RDE) were detected by re-oxidation charge. The dissolution time course of the hydrogen nanobubbles was measured by AFM tapping topography under open-circuit conditions at stationary platinum and gold single-crystal electrodes. The bubble dissolution at platinum was much faster than that at gold because two types of diffusion, bulk and surface diffusion, proceeded at the platinum surface, whereas surface diffusion was prohibited at the gold electrode. These findings indicated that the electrochemical reaction of normal hydrogen electrode partly proceeded heterogeneously on the three-phase boundary around the hydrogen nanobubble.

Humidity-dependent reversible aggregation of rhodamine 6G dye immobilized within layered niobate K4Nb6O17

The spectroscopic behavior of rhodamine 6G (R6G) dye intercalated in layered hexaniobate K4Nb6O17 was investigated. R6G cations were intercalated into the niobate through displacement of preintercalated alkylammonium ions. Powder X-ray diffraction and elemental analysis indicated that the dye molecules were densely accommodated in the interlayer spaces of niobate. The spectroscopic behavior of intercalated R6G was characterized by humidity-dependent aggregation at room temperature. The dye molecules were present dominantly as monomers under humid conditions (93% relative humidity (RH)), while they formed dimers under relatively dry conditions (20% RH). The aggregation-deaggregation of dye occurred reversibly depending on the humidity. The reversible aggregation was not accompanied by a large alteration of the interlayer structure of the sample, because only a small amount of water was adsorbed/desorbed with a small change in the basal spacing of the intercalation compound during the humidity change.

Association of benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid (BPDE-DNA) adduct level with aging in male smokers and nonsmokers

We used our new flow cytometric method to measure benzo[a]pyrene-diolepoxide-deoxyribonucleic acid adduct levels in peripheral lymphocytes from healthy male smokers and nonsmokers. Smokers who had pack-years of 20 or more had significantly higher mean benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels than nonsmokers. In smokers, the adduct levels were correlated significantly with age, years of smoking, and pack-years, whereas daily tobacco consumption was not correlated with adduct levels. We also found a positive relationship between age and benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels in nonsmokers. Passive exposure to tobacco smoke was not associated with adduct levels. The results of our study indicate that benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels may be closely related to aging and that tobacco smoking-as well as other environmental factors-may play a role in the benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct formation.

Release of cytokines from human umbilical vein endothelial cells treated with platinum compounds in vitro

Endothelial cells (EC) produce cytokines, such as interleukin (IL)-1, IL-6, IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF). These cytokines have an important role in the proliferation and differentiation of hematopoietic progenitor cells. On the other hand, anticancer agents generally cause hematopoietic disorders. However, little is known about the effects of chemotherapeutic agents on the secretion of cytokines from EC. Therefore, we investigated if treatment with platinum compounds may stimulate EC to secrete cytokines. EC newly isolated from a human umbilical vein were exposed to cisplatin, carboplatin, or TRK-710 for 80 min, then the cells were washed and placed in fresh medium. The levels of cytokines in the fresh medium were measured by the ELISA method, the levels of intracellular hydrogen peroxide (H2O2) were measured by flow cytometry, and the rhodamine 123-stained live mitochondria of the EC were observed under a confocal laser microscope. Platinum compounds induced cytokine production in human EC: cisplatin most prominently induced the release of IL-1 and IL-6, and TRK-710 had the greatest ability to induce the release of GM-CSF. Intracellular H2O2 production and IL-8 release were transiently induced immediately after treatment with platinum compounds, leading to IL-1 release when H2O2 production was eliminated. These results may provide new insights into the hematological toxicity induced by anticancer agents and the role of IL-1 and IL-6 secreted from EC in this toxicity.

Flow cytometric measurement of benzo[a]pyrene-diol-epoxide-DNA adducts in normal human peripheral lymphocytes and cultured human lung cancer cells

DNA adducts are mainly detected by 32P-postlabeling and enzyme-linked immunosorbent assays. We have established a method for detection of benzo[a]pyrene-diol-epoxide (BPDE)-DNA adducts by flow cytometry, and have clarified the effects of the DNA adducts on cell-cycle progression and the relationship between cell-cycle phases and DNA adduct formation, using human peripheral lymphocytes and three human lung cancer cell lines. We measured the BPDE-DNA adduct levels in both lymphocytes and cancer cells by isolating nuclei, using a nuclear isolation buffer containing Triton X-100 and staining with a BPDE-DNA-specific monoclonal antibody and biotin-streptavidin fluorescein conjugates. BPDE did not affect cell-cycle progression in human peripheral lymphocytes. However, in human lung cancer cells exposed to > 1 microg/ml BPDE, accumulation of cells in the S phase was seen. Cells with DNA content greater than G2M (aneuploid cells) or cells with less than G1 DNA content (apoptotic cells) increased gradually with exposure to increasing BPDE concentrations, suggesting that BPDE may affect cell-cycle progression through binding to DNA. Thus, the measurement of DNA adducts by flow cytometry may provide new insights into carcinogenesis.

Air pollution, temperature, and regional differences in lung cancer mortality in Japan

In this study, the authors investigated regional differences in lung cancer mortality in Japan, and, based on data acquired between 1970 and 1990 for 47 Japanese prefectures, estimated the relationship between regional lung cancer mortality and air pollution and/or temperature. Investigators used data for nitrogen dioxide, sulfur dioxide, motor vehicle density, tobacco expenditure, and temperature as independent variables for age-adjusted lung cancer death rates. The age-adjusted lung cancer death rates were higher in the southern geographical block of Japan (i.e., approximately 1.2-fold in males and 1.1-fold in females) and in the northern block (approximately 1.2-fold in males) than in the central block. The regional differences in the age-adjusted lung cancer death rates were explained by nitrogen dioxide and temperature. Temperature caused a greater effect (regression coefficients) of nitrogen dioxide on the age-adjusted lung cancer death rates than did nitrogen dioxide alone in the southern block (i.e., approximately 1.3-fold in males and 1.2-fold in females). These results provide the first evidence of a possible synergistic interaction between air pollution and high temperature on lung cancer mortality.

Acute immobilization stress and intraventricular injection of CRF suppress naloxone-induced LH release in ovariectomized estrogen-primed rats

The present study was undertaken to evaluate the role and possible interaction of the endogenous opioid peptide (EOP) and corticotropin-releasing factor (CRF) in the acute stress-induced suppression of gonadotropin secretion in ovariectomized estrogen-primed rats. An intravenous (i.v.) injection of naloxone (10 or 20 mg/kg), an EOP antagonist, significantly elevated serum luteinizing hormone (LH) levels within 10 min in non-stressed animals. The naloxone-induced LH release was completely eliminated when tested 30 min after the onset of acute immobilization. In a subsequent study, it was found that suppression of the naloxone-induced LH release occurred as early as 5 min after the stress onset, and was still evident 60 min after the end of a 30-min period of immobilization. The effect of naloxone was restored 3 h after liberation of the animal from the 30-min immobilization. An intraventricular (i.c.v.) injection of CRF (1 or 5 micrograms) also significantly suppressed, in a dose-related manner, the effect of a subsequent i.v. injection of naloxone. However, an i.c.v. injection of alpha-helical CRF(9-41) (25 or 50 micrograms), a CRF antagonist, prior to immobilization, could not interfere with the suppressive effect of stress on naloxone-induced LH release. These results suggest that both acute immobilization stress and CRF can inhibit the LH secretory activity without mediation by EOP neurons. However, the stress-related suppression may involve non-CRF mechanism(s).

Acute stress suppresses the N-methyl-D-aspartate-induced luteinizing hormone release in the ovariectomized estrogen-primed rat

The effects of N-methyl-D-aspartate (NMDA) and luteinizing hormone releasing hormone (LH-RH) on luteinizing hormone (LH) secretion were examined in ovariectomized estrogen-primed rats under nonstressed and acutely stressed conditions. The basal LH levels were significantly elevated 15 min after the onset of acute immobilization stress, but were not altered in emotionally stressed or nonstressed rats. Intravenous injections of 10 and 40 mg/kg NMDA significantly elevated serum LH levels by 161 and 212%, respectively, from baseline within 10 min in nonstressed animals. However, the NMDA-induced LH release was significantly reduced when tested 30 min after the onset of acute immobilization stress. Acute emotional stress, which did not affect the baseline LH, also suppressed the LH release response to NMDA, suggesting that the reduced LH responses to NMDA in stressed animals was not due to the elevated baseline level. Pituitary LH release responses to LH-RH were not affected by acute immobilization. We conclude from these results: (1) acute immobilization stress exerts both stimulatory and inhibitory effects on LH release, while acute emotional stress has only an inhibitory effect in estrogen-primed ovariectomized rats; (2) this inhibition occurs at the suprapituitary level, and (3) it involves a suppression of the responsiveness of the hypothalamic LH-RH neuronal system to the excitatory amino acid input.