Continuous Exposure to Low-Dose-Rate Gamma Irradiation Reduces Airway Inflammation in Ovalbumin-Induced Asthma

Although safe doses of radiation have been determined, concerns about the harmful effects of low-dose radiation persist. In particular, to date, few studies have investigated the correlation between low-dose radiation and disease development. Asthma is a common chronic inflammatory airway disease that is recognized as a major public health problem. In this study, we evaluated the effects of low-dose-rate chronic irradiation on allergic asthma in a murine model. Mice were sensitized and airway-challenged with ovalbumin (OVA) and were exposed to continuous low-dose-rate irradiation (0.554 or 1.818 mGy/h) for 24 days after initial sensitization. The effects of chronic radiation on proinflammatory cytokines and the activity of matrix metalloproteinase-9 (MMP-9) were investigated. Exposure to low-dose-rate chronic irradiation significantly decreased the number of inflammatory cells, methylcholine responsiveness (PenH value), and the levels of OVA-specific immunoglobulin E, interleukin (IL)-4, and IL-5. Furthermore, airway inflammation and the mucus production in lung tissue were attenuated and elevated MMP-9 expression and activity induced by OVA challenge were significantly suppressed. These results indicate that low-dose-rate chronic irradiation suppresses allergic asthma induced by OVA challenge and does not exert any adverse effects on asthma development. Our findings can potentially provide toxicological guidance for the safe use of radiation and relieve the general anxiety about exposure to low-dose radiation.     

Comparison of sensory tests and neuronal quantity of peripheral nerves between streptozotocin (STZ)-induced diabetic rats and paclitaxel (PAC)-treated rats

Although diabetic peripheral neuropathy (DPN) and chemotherapy-induced peripheral neuropathy (CIPN) are different disease entities, they share similar neuropathic symptoms that impede quality of life for these patients. Despite having very similar downstream effects, there have been no direct comparisons between DPN and CIPN with respect to symptom severity and therapeutic responses. We compared peripheral nerve damage due to hyperglycemia with that caused by paclitaxel (PAC) treatment as represented by biochemical parameters, diverse sensory tests, and immunohistochemistry of cutaneous and sciatic nerves. The therapeutic effects of alpha-lipoic acid and DA-9801 were also compared in the two models. Animals were divided into seven groups (n?=?7–10) as follows: normal, diabetes (DM), DM?+?alpha-lipoic acid 100?mg/kg (ALA), DM?+?DA-9801 (100?mg/kg), paclitaxel-treated rat (PAC), PAC?+?ALA (100?mg/kg), and PAC?+?DA-9801 (100?mg/kg). The sensory thresholds of animals to mechanical, heat, and pressure stimuli were altered by both hyperglycemia and PAC when compared with controls, and the responses to sensory tests were different between both groups. There were no significant differences in the biochemical markers of blood glutathione between DM and PAC groups (p?>?.05). Quantitative comparisons of peripheral nerves by intraepidermal nerve fiber density (IENFD) analysis indicated that the DM and PAC groups were similar (6.18?±?1.03 vs. 5.01?±?2.57). IENFD was significantly improved after ALA and DA-9801 treatment in diabetic animals (7.6?±?1.28, 7.7?±?1.28, respectively, p?p?>?.05). Sciatic nerves were less damaged in the PAC-treated groups compared with the DM groups with respect to axonal diameter and area (8.60?±?1.14?μm vs. 6.66?±?1.07?μm, and 59.04?±?15.16?μm² vs. 35.71?±?11.2?μm², respectively, p?相似文献   

Evaluation of Repellency Effect of Two Natural Aroma Mosquito Repellent Compounds,Citronella and Citronellal*

Repellent efficacies of two natural aroma compounds, citronella and citronellal, against mosquitoes, Culex pipiens pallens, were evaluated both in field and in vitro. In vitro, the experiment was conducted with three controlled bands impregnated with 30% citronella extract, 15% citronella extract and 30% citronellal extract, and with bands impregnated 30% citronella in field. Data was obtained by the means of counting numbers bitten by mosquitoes per unit time, namely human bait method. Percentage repellencies of above three controlled bands were calculated at 86%, 73%, and 78%, respectively in vitro, and 80% in field, showing high repellent effectiveness against mosquitoes. This estimation was also confirmed by t‐test compared between control group and each experimental group.     

IL-5 induces a Pgp-1 (CD44) bright B cell subpopulation that is highly enriched in proliferative and Ig secretory activity and binds to hyaluronate

Pgp-1 expression was examined in unstimulated B cell populations and in B cells activated with several polyclonal stimuli. Flow cytometry analysis demonstrated that Pgp-1 expression increased when B cells were activated with supernatant of cloned Th2 cells, with LPS, or with IL-5, stimuli that induced polyclonal proliferation and differentiation. IL-5-primed B cells were phenotypically unique and could be divided into two distinct subpopulations based on the brightness of Pgp-1 expression. Furthermore, sterile sorting experiments showed that proliferating and differentiating B cells were highly enriched in a Pgp-1-bright, Ia-dull, B220-dull subpopulation. The possibility that Pgp-1 expressed on activated B cells functions as an adhesion molecule was evaluated by assessing adhesion of activated B cells to defined substrates. It was found that IL-5-activated B cells bound strongly to hyaluronate-coated surface, and this binding was specifically inhibited by anti-Pgp-1 Ab. These findings suggest that Pgp-1 expression is a useful marker which, under defined conditions, identifies the proliferating and differentiating subset of activated B cells. Moreover, the Pgp-1 bright subset of IL-5-primed B cells binds to hyaluronate in a Pgp-1-dependent manner that suggests a potential role of Pgp-1 in the in vivo adherence and trafficking of activated B cells.     

Effects of Ethylene on the Kinetics of Curvature and Auxin Redistribution in Gravistimulated Roots of Zea mays

We tested the involvement of ethylene in maize (Zea mays L.) root gravitropism by measuring the kinetics of curvature and lateral auxin movement in roots treated with ethylene, inhibitors of ethylene synthesis, or inhibitors of ethylene action. In the presence of ethylene the latent period of gravitropic curvature appeared to be increased somewhat. However, ethylene-treated roots continued to curve after control roots had reached their final angle of curvature. Consequently, maximum curvature in the presence of ethylene was much greater in ethylene-treated roots than in controls. Inhibitors of ethylene biosynthesis or action had effects on the kinetics of curvature opposite to that of ethylene, i.e. the latent period appeared to be shortened somewhat while total curvature was reduced relative to that of controls. Label from applied ³H-indole-3-acetic acid was preferentially transported toward the lower side of stimulated roots. In parallel with effects on curvature, ethylene treatment delayed the development of gravity-induced asymmetric auxin movement across the root but extended its duration once initiated. The auxin transport inhibitor, 1-N-naphthylphthalamic acid reduced both gravitropic curvature and the effect of ethylene on curvature. Since neither ethylene nor inhibitors of ethylene biosynthesis or action prevented curvature, we conclude that ethylene does not mediate the primary differential growth response causing curvature. Because ethylene affects curvature and auxin transport in parallel, we suggest that ethylene modifies curvature by affecting gravity-induced lateral transport of auxin, perhaps by interfering with adaptation of the auxin transport system to the gravistimulus.     

Alkaline and Acid Phosphatase Demonstration in Human Bone and Cartilage: Effects of Fixation Interval and Methacrylate Embedments

Human bone and cartilage specimens were evaluated for acid and alkaline phosphatase localization following varying fixation periods for fresh or frozen tissue. Formalin fixations of up to 183 hr were followed by embedment in methyl methacrylate; frozen tissue was examined either without fixation or following fixation for up to 1 hr and subsequent glycol or methyl methacrylate embedding. The humeral epiphysis of a young patient with osteogenic sarcoma showed optimum acid and alkaline phosphatase localization following fixation for periods up to 15 hr and embedding in methyl methacrylate. Frozen costochondral junction from a newborn with osteogenesis imperfecta type II showed optimum acid and alkaline phosphatase localization following 30 min fixation in formalin and embedding in methyl methacrylate or after 5 min fixation and embedding in glycol methacrylate.     

Expression of the human epidermal growth factor receptor in a murine T-cell hybridoma. A transmembrane protein tyrosine kinase can synergize with the T-cell antigen receptor.

Although the T-cell receptor for antigen (TCR) lacks intrinsic kinase activity, stimulation of this receptor induces tyrosine phosphorylation of multiple substrates. In contrast, the epidermal growth factor receptor (EGFR) has intrinsic cytoplasmic tyrosine kinase catalytic activity that is activated upon EGF binding. To compare the functional effects of the TCR and a transmembrane protein tyrosine kinase (PTK), we used retrovirus-mediated gene transduction to express the human c-erbB proto-oncogene, encoding the EGFR, in a murine T-cell hybridoma. Tyrosine phosphorylation induced by the TCR and the EGFR occurred on substrates unique to each receptor as well as on several shared substrates, including the zeta chain of the TCR. Stimulation of the EGFR induced calcium ion flux in these cells, suggesting that the heterologous tyrosine kinase can couple to the T-cell phospholipase signal transduction pathway, but this stimulus did not lead to interleukin 2 production. However, EGF stimulation of transduced cells significantly enhanced TCR signaling, as assessed by interleukin 2 production, indicating that cross talk can occur between the TCR and a transmembrane PTK.     

Characterization of the binding of ferritin to the rat liver ferritin receptor

The binding characteristics and specificity of the rat hepatic ferritin receptor were investigated using ferritins prepared from rat liver, heart, spleen, kidney and serum, human liver and serum, guinea pig liver and horse spleen as well as ferritins enriched with respect to either H- or L-type subunit composition, prepared by chromatofocusing of rat liver ferritin on Mono-P or by reverse-phase chromatography of ferritin subunits on ProRPC 5/10. No significant difference was apparent in the binding of any of the tissue ferritins, or of ferritins of predominantly acidic or basic subunit composition. However, serum ferritin bound with a lower affinity. The effect of carbohydrate on the ferritin-receptor binding was examined by glycosidase treatment of tissue and serum ferritins. Tissue ferritin binding was unaffected, while serum ferritin binding affinity was increased to that of the tissue ferritins. Inhibition of ferritin binding by lactoferrin was not due to common carbohydrate moieties as previously suggested but was due to direct binding of lactoferrin to ferritin. Therefore, carbohydrate residues do not appear to facilitate receptor-ferritin binding, and sialic acid residues present on serum ferritin may in fact interfere with binding. The results indicate that the hepatic ferritin receptor acts preferentially to remove tissue ferritins from the circulation. The lower binding affinity of serum ferritin for the ferritin receptor explains its slower in vivo clearance relative to tissue ferritins.