Involvement of superoxide and nitric oxide on airway inflammation and hyperresponsiveness induced by diesel exhaust particles in mice

We previously demonstrated that chronic intratracheal instillation of diesel exhaust particles (DEP) induces airway inflammation and hyperresponsiveness in the mouse, and that these effects were partially reversed by the administration of superoxide dismutase (SOD). In the present study, we have investigated the involvement of superoxide in DEP-induced airway response by analyzing the localization and activity of two enzymes: (1) a superoxide producer, NADPH cytochrome P-450 reductase (P-450 reductase), and (2) a superoxide scavenger, SOD, in the lungs of the exposed mice and controls. P-450 reductase was detected mainly in ciliated cells and clara cells: its activity was increased by the repeated intratracheal instillation of DEP. While CuZn-SOD and Mn-SOD were also present in the airway epithelium, their activity was significantly decreased following DEP instillation. Exposure to DEP doubled the level of nitric oxide (NO) in the exhaled air. DEP exposure also increased the level of constitutive NO synthase (cNOS) in the airway epithelium and inducible NO synthase (iNOS) in the macrophages. Pretreatment with N-G-monomethyl L-arginine, a nonspecific inhibitor of NO synthase, significantly reduced the airway hyperresponsiveness induced by DEP. These results indicate that superoxide and NO may each contribute to the airway inflammation and hyperresponsiveness induced by the repeated intratracheal instillation of DEP in mice.     

Mu and kappa opioid receptors in periaqueductal gray and rostral ventromedial medulla

The periaqueductal gray (PAG) and rostral ventromedial medulla (RVM) are important brain stem pain modulating regions. Recent evidence suggests that kappa opioids antagonize the effects of mu opioids in the RVM. However, the anatomical relationship between mu and kappa opioid receptors in PAG and RVM is not well characterized. This study examined relationships between mu and kappa opioid receptor immunoreactivity (IR) and mRNA in PAG and RVM. Brain slices were processed for either immunocytochemistry or in situ hybridization. We found considerable anatomical overlap of mu and kappa opioid IR and mRNA in the RVM and PAG. These results provide an anatomical basis for recent behavioral and electrophysiological findings in RVM, and suggest modulatory interactions between mu and kappa opioids in PAG.     

3-Alkanoyl-5-hydroxymethyl tetronic acid homologues and resistomycin: new inhibitors of HIV-1 protease. I. Fermentation, isolation and biological activity

In the course of a screening program for HIV-1 protease inhibiting activity, six new homologues of 3-alkanoyl-5-hydroxymethyl tetronic acids (1 approximately 6) and the known natural product resistomycin (7) were isolated from cultures of the Actinomycete strain DSM 7357. The substituted tetronic acids belong to a recently described structural class of secondary metabolites. The HIV-1 activity of resistomycin (7) has not been reported before.     

Comparison of hemodynamic and regional blood flow changes at equivalent stages of endotoxin and hemorrhagic shock

Hemodynamic, respiratory, and regional blood flow measurements were carried out in two groups of monkeys at three roughly equivalent stages of endotoxin and hemorrhagic shock. Comparisons revealed characteristic differences at the two early stages, particularly in systemic vascular resistance and the pattern of distribution of cardiac output. However, at the final stage of shock, these patterns had merged and there were no characteristic differences between the two groups. The pathologic significance of these findings, in terms of the endotoxin theory of irreversible hemorrhagic shock and the realtive contributions of vasoactive humoral substances at various stages of the two forms of shock, is discussed.     

Some responses of Chrysanthemum morifolium (cv.“hurricane”), grown as a year-round crop in a peat-sand substrate,to micronutrients and liming

The effects of a fritted micronutrient mixture on the growth and flowering of spray chrysanthemums (cv.“Hurricane”) were studied in relation to pH in a peatsand substrate (3:1 by volume). The treatments consisted of three rates of application of a fritted micronutrient mixture (0, 200, 500 g/m³) in factorial combination with four rates of liming (average pH values 4.2, 5.0, 6.3 and 7.1). Five successive crops were grown under conditions, including controlled day-length, used commercially for year-round chrysanthemum production. Bud initiation and development were greatly delayed in the absence of micro-nutrients, particularly at high pH, and some plants failed to flower. The proportion of marketable sprays was decreased by omission of micronutrients (P<0.001) and by liming (P<0.001), and those that were saleable were reduced in size. Omission of micronutrients decreased the numbers of flowers per spray (P<0.001). Plants grown without added micronutrients developed more leaves and bracts on their lateral shoots (P<0.001), particularly at high pH (6.3–7.1); the interaction between lime and micronutrients was significant at P<0.01. Leaf samples were analysed for micronutrient content (B, Fe, Mn, Cu and Zn). Symptoms of boron deficiency (“quilling” of the petals) were recorded and shown to be significantly correlated with the boron content of the leaves (P<0.001). The copper content of plants grown without added micronutrients was well below the published critical level, and this deficiency is considered responsible for many of the effects observed.     

Age-related disruption of trace but not delay classical conditioning of the rabbit's nictitating membrane response.

16 6-mo-old and 15 36–60 mo old New Zealand albino rabbits underwent classical conditioning of the nictitating membrane response in either a delay conditioning (Exp I) or a trace conditioning (Exp II) paradigm. There was no difference between old and young Ss in the acquisition of the CR in the delay paradigm, nor were there any age-related differences in generalization to the tone CS or in sensitivity to the tone CS or eyeshock UCS. However, in the trace conditioning paradigm, old Ss acquired the CR significantly more slowly than young Ss. Because the same stimulus parameters and the same response were used in both experiments, it is unlikely that age-related differences in trace conditioning were due to stimulus sensitivity, motivation, or fatigue. Results are discussed in terms of how brain changes that accompany aging could differentially affect these 2 types of classical conditioning. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)