Influence of stress on morphine-induced hyperthermia: Relevance to drug conditioning and tolerance development.

Three experiments, with 64 Holtzman and 48 Wistar male rats, examined whether Ss would become tolerant, or sensitized, to morphine-induced hyperthermia and the directionality of the conditioned pyretic effects of morphine. Stress produced by temperature-assessment procedures affected Ss' pyretic response to morphine. Under conditions of high stress, Ss first showed diminished, and then enhanced, hyperthermic responding across repeated dosing with morphine sulfate (5 or 35 mg/kg, sc). The diminished hyperthermia can be attributed to habituation to high levels of assessment stress. Repeated morphine doses delivered under conditions of low stress produced only enhanced hyperthermic responding, indicating that Ss became sensitized to morphine's hyperthermic effects. There was little evidence that morphine supported conditioning of pyretic responses. The temperature-assessment stress that produced hyperthermia was mediated by opiate peptides, was blocked by naloxone, and enhanced the agonist effects of morphine. Implications for theories of drug conditioning and tolerance are discussed. (57 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization and distribution of basic fibroblast growth factor-containing cells in the rat hippocampus

Basic fibroblast growth factor (bFGF), a member of the heparin-binding growth factor family, is present in relatively high levels in the brain where it may play an important role in the maintenance, repair, and reorganization of the tissue. Although bFGF is associated mainly with astrocytes throughout most of the central nervous system (CNS), a narrow but prominent band of pyramidal neurons, which coincides with the CA2 subregion of Ammon's horn in the hippocampus, stains intensely for bFGF. In order to gain an understanding of which cells express bFGF and whether or not BFGF is a good marker for CA2 neurons, we have used a mouse monoclonal antibody directed against recombinant human bFGF to characterize the distribution and localization of bFGF expression in the hippocampus. We find that about one-quarter of the neurons in CA2 are bFGF positive, and they appear smaller and have more irregular-shaped nuclei than their unstained counterparts. In addition, all glial fibrilary acidic protein (GFAP)-positive astrocytes in the hippocampus stain for bFGF, and the distribution of these astrocytes is heterogeneous in the hippocampus. Finally, in both astrocytes and CA2 pyramidal neurons, bFGF immunoreactivity is localized primarily in the nucleus and to a lesser extent in the cytoplasm and processes of stained cells.     

Interaction behaviors of primary versus secondary caretaker fathers.

A comparison was made between the videotaped behaviors of primary caretaker mothers and both primary and secondary caretaker fathers during face-to-face interactions with their 4-mo-old infants. The sample consisted of 36 infants, 12 observed with their primary caretaker mothers, 12 with primary caretaker fathers, and 12 with secondary caretaker fathers. Fathers in general tended to engage in significantly more game playing and less holding of their infants. Primary caretaker fathers and mothers engaged in significantly more smiling, imitative grimaces, and high-pitched imitative vocalizations than did secondary caretaker fathers. These differences were related to the primary caretaker mothers' and fathers' greater familiarity with their infants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Morphine tolerance as habituation.

Demonstrates that the development of tolerance to morphine conforms to A. R. Wagner's (1979) priming model of habituation. Tolerance develops through both associational and nonassociational routes: The development of associational tolerance is attributed to retrieval-generated priming of memory, whereas nonassociational tolerance is attributed to self-generating priming. This model accounts for the effects of dose level, drug signaling, and interdose interval on tolerance development. Also, a habituation model is consistent with data showing that dose level and interdose interval affect the impact of drug signals on tolerance development. Limitations of the habituation model are noted with respect to the development of tolerance in vitro, sensitization, and CRs antagonistic to initial drug effects. (5 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social unrest: Powerlessness and/or self-direction?

Presents a theoretical model for understanding social unrest which is based on the experience of control. It is proposed that social unrest indicates powerlessness and consequently an inability to make self-directed choices to alter one's environment. The model postulates 4 interacting components or sources of behavioral determinants: (a) control from internal organismic states (e.g., impulses), (b) control over these internal states, (c) control over the environment, and (d) control from the environment. It is argued that social unrest must be dealt with in terms of the resources of the social sciences and not in political or managerial priorities. The question of whether social unrest is the outgrowth of the effects of social systems on individuals (overemphasis of control from the environment) or enlightenment regarding the individual's self-directing potential (increased control over the environment) is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Survival of pathogenic bacteria in pesticide solutions and on treated tomato plants

The ability of Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Shigella to survive or grow in pesticide solutions (Ambush 240EC, Benlate T-N-G, Bravo 500, Botran 75WP, Captan 80WDG, Parasol, and Vendex 50W) used by the horticultural industry was examined. In the laboratory, individual cultures were inoculated at 4 log CFU/ml in pesticides diluted with sterile saline to the lowest recommended spray concentrations. During 21 degrees C incubation for < or =96 h, bacterial survivors in the samples and a control consisting of saline were enumerated either by agar surface plating or hydrophobic grid membrane filtration. Most formulations tested were somewhat inhibitory to the pathogenic bacteria. All inoculated bacteria survived or grew in Bravo 500. Among bacteria tested, Salmonella spp. were best able to survive and Listeria spp. were least able to survive in pesticide solutions. When the incubation temperature or pesticide concentration was increased, survival of Salmonella varied depending on the type of formulation. In the field, when a bacterial cocktail containing E. coli O157:H7 and Salmonella Enteritidis was added to Bravo 500 at 6 log CFU/ml, both organisms were recovered from leaves and fruit skins of sprayed tomato plants after the recommended 1 day-to-harvest interval. E. coli and Salmonella survived longer on tomato leaves when sprayed in saline (at least 26 and 56 days, respectively) than when sprayed in Bravo 500 (>45 h and <15 days, respectively). While Salmonella serovars Typhimurium and Heidelberg grew in the fungicide Bravo, and Enteritidis grew in the insecticide Vendex within 96 h at 21 degrees C in the laboratory, pathogen growth in other pesticide formulations did not occur. Higher temperature (< or =30 degrees C) or doubling pesticide concentrations had either no or a negative effect on Salmonella Heidelberg survival. Use of unexpired pesticide formulations may have contributed to the reduced bacterial survival and growth found in the laboratory and during the field trials with Bravo.     

CXCR4 and CCR5 on human thymocytes: biological function and role in HIV-1 infection

Thymocyte infection with HIV-1 is associated with thymic involution and impaired thymopoiesis, particularly in pediatric patients. To define mechanisms of thymocyte infection, we examined human thymocytes for expression and function of CXCR4 and CCR5, the major cell entry coreceptors for T cell line-tropic (T-tropic) and macrophage-tropic (M-tropic) strains of HIV-1, respectively. CXCR4 was detected on the surface of all thymocytes. CXCR4 expression on mature, high level TCR thymocytes was similar to that on peripheral blood T cells, but was much lower than that on immature thymocytes, including CD34+ thymic progenitors. Consistent with this, stroma-derived factor-1 (SDF-1) induced calcium flux primarily in immature thymocytes, with CD34+ progenitors giving the strongest response. In addition, SDF-1 mRNA was detected in thymic-derived stromal cells, and SDF-1 induced chemotaxis of thymocytes, suggesting that CXCR4 may play a role in thymocyte migration. Infection of immature thymocytes by the T-tropic HIV-1 strain LAI was 10-fold more efficient than that in mature thymocytes, consistent with their relative CXCR4 surface expression. Anti-CXCR4 antiserum or SDF-1 blocked fusion of thymocytes with cells expressing the LAI envelope. In contrast to CXCR4, CCR5 was detected at low levels on thymocytes, and CCR5 agonists did not induce calcium flux or chemotaxis in thymocytes. However, CD4+ mature thymocytes were productively infected with the CCR5-tropic strain Ba-L, and this infection was specifically inhibited with the CCR5 agonist, macrophage inflammatory protein-1beta. Our data provide strong evidence that CXCR4 and CCR5 function as coreceptors for HIV-1 infection of human thymocytes.     

X-ray diffraction studies of electrochemical graphite intercalation compounds of ionic liquids

Electrochemical intercalation studies are used to characterize a series of ionic liquids composed of a variety of cationic and anionic species. Electrochemically, the ionic liquids are characterized by cyclic voltammograms and charge–discharge experiments for the intercalation and de-intercalation of the various cationic and anionic species into graphite. X-ray structure analysis is also performed to determine the relationship between the electrochemical behaviour of the ionic liquids, and the formation of intercalated graphitic compounds. Two different types of imidazolium cations are studied, specifically the di- and trisubstituted imidazolium. These cations are paired with the following anions: tetrafluoroborate, hexafluorophosphate, bis(trifluoromethanesulfonyl)imide, bis(perfluoroethanesulfonyl)imide, nitrate and hydrogen sulfate. Results indicate stronger intercalation chemistry for the trisubstituted imidazoliums, correlating with the greater charge–discharge efficiencies found for these types of ionic liquids. Many of the anions exhibit very poor charge–discharge efficiencies, correlating to very poorly formed graphite intercalates. The exception to this is the hydrogen sulfate intercalate, which had low charge–discharge efficiencies but formed a well defined graphite intercalate. Only the imide based anions exhibited both high charge–discharge efficiencies and the formation of a clearly defined graphite intercalate.     

Sediment geochemistry of Al, Fe, and P for two historically acidic, oligotrophic Maine lakes

Phosphorus (P) may be liberated from lake sediments by reductive dissolution of Fe(OH)(3(S)) during periods of hypolimnetic anoxia. P, however, remains adsorbed to Al(OH)(3(S)) regardless of redox conditions. During chronic or episodic acidification of a catchment, ionic Al is mobilized from soils to receiving waters. A fraction of the mobilized Al may precipitate as a consequence of higher pH of the receiving waters. We hypothesized that phosphorus retention in lake sediments is directly related to the magnitude of Al loading in response to low pH in the watershed. We studied cores representing over 200 years of sediment accumulation in historically acidic Mud Pond and Little Long Pond in eastern Maine, USA. Sequential chemical extractions of sediment were used to assess the history of Al, Fe, and P interactions. Mud Pond is a first-order pond with a pH of approximately 4.7, having acidified slightly in response to anthropogenic acidification from approximately 1930. The inlet stream to Mud Pond has dissolved Al concentrations often exceeding 500 microg/L, of which more than half is organically-bound. Mud Pond drains into Little Long Pond, a second-order pond with a historical pH of <6, and which has shown little pH or alkalinity response to increases or decreases in atmospheric SO(4)(2-) input. Sequential extractions show that Al and P are predominantly in the 0.1 M NaOH-extractable fraction in the sediments from both ponds throughout the cores. The concentration of the likely biogenic and non-reactive P within the NaOH fraction increases up core from <30% to approximately 60%. Extractable Fe (<20% of extractable Al) is mainly in the 0.1 M NaOH-extractable fraction, except for the top few cm, which are predominantly in the bicarbonate-dithionite reducible fraction. Accumulation rates of sediment, Al, Fe, and P in both ponds have increased in the last 50-60 yr, but fractions remain in the same proportion. Throughout both sediment cores the molar ratio of specific Al:P fractions greatly exceeds 25, and molar ratio of specific Al:Fe fractions greatly exceeds 3, the thresholds proposed by Kopácek et al. [Kopácek J, Borovec J, Hejzlar J, Ulrich K-U, Norton SA, Amirbahman A. Aluminum control of phosphorus sorption by lake sediments. Environ Sci Technol 2005; 39: 8784-89.] for P release during anoxia. The data illustrate a continuous association of P with Al in both ponds during the last two centuries, likely due to the persistent natural acidity of the catchments.