La dénervation rénale unilatérale et le système kallikréine-bradykinine rénal chez le rat

But de l’étude L’effet antihypertenseur de la dénervation rénale chez les patients hypertendus s’explique partiellement par une augmentation de la natriurèse tubulaire. Pour étudier une contribution possible du système kallikréine-kinines (SKK) à cette natriurèse dans le rat, nous avons dosé dans le plasma et dans les tissus l’activité de la kallikréine (AK) et la concentration de la bradykinine (BK). Méthodes Pour AK, nous avons adapté et validé un essai enzymatique qui libère la para-nitroaniline à partir du tripeptide H-D-Pro-Phe-Arg-pNA ; les coefficients de variation (CV) intra-essai et inter-essai étaient inférieurs à 8 % pour AK plasmatique et tissulaire (plasma n = 6 et 13, tissu n = 4). La linéarité d’une série de dilutions confirmait la spécificité de l’essai. Le dosage de BK tissulaire se basait sur une méthode établie pour le plasma : tissus étaient homogénéisés et BK extraite et isolée par éthanol et HPLC, et finalement quantifiée par radio-immunoessai. Les CV intra- et inter-essai pour BK étaient 18 % dans le plasma (n = 8 et n = 35) et inférieurs à 16 % dans différents tissus (n = 5–8). Résultats Chez le rat mâle Wistar (n = 3), la BK plasmatique était de 8,2 ± 6,6 fmol/mL (M ± SD) et la BK tissulaire (fmol/g) variait, pour les 14 organes testés, de 14 ± 3 pour le cerveau à 521 ± 315 pour la glande sous-maxillaire. Six jours après dénervation rénale gauche, la BK rénale gauche (89 ± 9) n’était pas différente comparée à la BK rénale droite (75 ± 23). De même, l’AK était identique dans les deux reins (gauche 18,0 ± 1,5, droit 15,8 ± 1,4 μkat/g). Conclusion Un effet éventuel de la dénervation rénale unilatéral sur le SKK rénal devrait donc être bilatéral.

Antimicrobial effects of murine mesenchymal stromal cells directed against Toxoplasma gondii and Neospora caninum: role of immunity-related GTPases (IRGs) and guanylate-binding proteins (GBPs).

Mesenchymal stromal cells (MSCs) have a multilineage differentiation potential and provide immunosuppressive and antimicrobial functions. Murine as well as human MSCs restrict the proliferation of T cells. However, species-specific differences in the underlying molecular mechanisms have been described. Here, we analyzed the antiparasitic effector mechanisms active in murine MSCs. Murine MSCs, in contrast to human MSCs, could not restrict the growth of a highly virulent strain of Toxoplasma gondii (BK) after stimulation with IFN-γ. However, the growth of a type II strain of T. gondii (ME49) was strongly inhibited by IFN-γ-activated murine MSCs. Immunity-related GTPases (IRGs) as well as guanylate-binding proteins (GBPs) contributed to this antiparasitic effect. Further analysis showed that IFN-γ-activated mMSCs also inhibit the growth of Neospora caninum, a parasite belonging to the apicomplexan group as well. Detailed studies with murine IFN-γ-activated MSC indicated an involvement in IRGs like Irga6, Irgb6 and Irgd in the inhibition of N. caninum. Additional data showed that, furthermore, GBPs like mGBP1 and mGBP2 could have played a role in the anti-N. caninum effect of murine MSCs. These data underline that MSCs, in addition to their regenerative and immunosuppressive activity, function as antiparasitic effector cells as well. However, IRGs are not present in the human genome, indicating a species-specific difference in anti-T. gondii and anti-N. caninum effect between human and murine MSCs.

Strategies for reducing fumigant loss to the atmosphere

A model is developed to describe transport and loss of methyl bromide (MeBr) in soil following application as a soil fumigant. The model is used to investigate the effect of soil and management factors on MeBr volatilization. Factors studied include depth of injection, soil water content, presence or absence of tarp, depth to downward barrier, and irrigation after injection. Of these factors, the most important was irrigation after injection followed by covering with the tarp, which increased the diffusive resistance of the soil and prevented early loss of MeBr. The model offers an explanation for the apparently contradictory observations of earlier field studies of MeBr volatilization from soils under different conditions. The model was also used to calculate the concentration-time index for various management alternatives, showing that the irrigation application did not make the surface soil more difficult to fumigate, except at very early times. Therefore, irrigation shows promise for reducing fumigant loss while at the same time permitting control of target organisms during fumigation.

The electrophysiology of glomerular mesangial cells

Glomerular mesangial cells (MC) are renal vascular cells that regulate the surface area of glomerular capillaries and thus, partly control glomerular filtration rate. Clarification of the signal transduction pathways and ionic mechanisms modulating MC tone are critical to understanding the physiology and pathophysiology of these cells, and the integrative role these cells play in fluid and electrolyte homeostasis. The patch clamp technique and an assay of cell concentration were used to electrophysiologically and pharmacologically analyze the ion channels of the plasmalemmal of human glomerular MC maintained in tissue culture. Moreover, the signal transduction pathways modulating channels involved in relaxation were investigated. Three distinct K$\sp+$-selective channels were identified: two low conductance channels (9 and 65pS) maintained MC at rest, while a larger conductance (206pS) K$\sp+$ channel was quiescent at rest. This latter channel was pharmacologically and biophysically similar to the large, Ca$\sp{2+}$-activated K$\sp+$ channel (BK$\rm\sb{Ca}$) identified in smooth muscle. BK$\rm\sb{Ca}$ played an essential role in relaxation of MC. In cell-attached patches, the open probability (P$\rm\sb{o}$) of BK$\rm\sb{Ca}$ increased from a basal level of $<$0.05 to 0.22 in response to AII (100nM)-induced mobilization of cytosolic Ca$\sp{2+}$. Activation in response to contractile signals (membrane depolarization and Ca$\sp{2+}$ mobilization) suggests that BK$\rm\sb{Ca}$ acts as a low gain feedback regulator of contraction. Atrial natriuretic factor (ANF; 1.0$\mu$M) and nitroprusside (NP; 0.1mM), via the second messenger, cGMP, increase the feedback gain of BK$\rm\sb{Ca}$. In cell-attached patches bathed with physiological saline, these agents transiently activated BK$\rm\sb{Ca}$ from a basal $\rm P\sb{o}<0.05$ to peak responses near 0.50. As membrane potential hyperpolarizes towards $\rm E\sb{K}$ (2-3 minutes), BK$\rm\sb{Ca}$ inactivates. Upon depolarizing V$\rm\sb{m}$ with 140 mM KCl, db-cGMP (10$\mu$M) activated BK$\rm\sb{Ca}$ to a sustained P$\rm\sb{o}$ = 0.51. Addition of AII in the presence of cGMP further increased P$\rm\sb{o}$ to 0.82. Activation of BK$\rm\sb{Ca}$ by cGMP occured via an endogenous cGMP-dependent protein kinase (PKG): in excised, inside-out patches, PKG in the presence of Mg-ATP (0.1mM) and cGMP increased P$\rm\sb{o}$ from 0.07 to 0.39. In contrast, neither PKC nor PKA influenced BK$\rm\sb{Ca}$. Endogenous okadaic acid-sensitive protein phosphatase suppressed BK$\rm\sb{Ca}$ activity. Binning the change in P$\rm\sb{o}\ (\Delta P\sb{o}$) of BK$\rm\sb{Ca}$ in response to PKG (n = 69) established two distinct populations of channels: one that responded ($\cong$67%, $\rm\Delta P\sb{o} = 0.45 \pm 0.03$) and one that was unresponsive ($\Delta\rm P\sb{o} = 0.00 \pm 0.01$) to PKG. Activation of BK$\rm\sb{Ca}$ by PKG resulted from a decrease in the Ca$\sp{2+}$- and voltage-activation thresholds independent of sensitivities. In conclusion, mesangial BK$\rm\sb{Ca}$ channels sense both electrical and chemical signals of contraction and act as feedback regulators by repolarizing the plasma membrane. ANF and NO, via cGMP, stimulate endogenous PKG, which subsequently decreases the activation threshold of BK$\rm\sb{Ca}$ to increase the gain of this feedback regulatory signal. ^

Review of lattice results concerning low-energy particle physics

We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the lightquark masses, the form factor f+(0), arising in semileptonic K → π transition at zero momentum transfer, as well as the decay-constant ratio fK / fπ of decay constants and its consequences for the CKM matrix elements Vus and Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)L × SU(2)R and SU(3)L×SU(3)R Chiral Perturbation Theory and review the determination of the BK parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, we focus here on D- and B-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant αs.

Contes et légendes d'Israe͏̈l

par A. Weil. Ill. de Kuhn Régnier

Jewish fairy tales

translated by Gerald Friedlander. Ill. by Beatrice Hirschfeld

Mährchen für Kinder

erzählt von Aurelie. Mit 3 Zeichn. in Farbendr. von Ludwig Burger

Hisṭorie fon der šehne kenigliche printzesin Helene welche durch eini wasr fahrṭ zo fr unglikṭi ds zi muzṭ ir brohṭ beṭlin gehn

Digitalisat der Ausg. Frankfurt an der Oder, 1782/83

Institutions for sustainable governance of forests: Equity, robustness and cross-level interactions in Mawlyngbna, Meghalaya, India

This study adopts Ostrom’s Social-Ecological Systems (SES) framework in empirical fieldwork to explain how local forestry institutions affect forest ecosystems and social equity in the community of Mawlyngbna in North-East India. Data was collected through 26 semi-structured interviews, participatory timeline development, policy documents, direct observation, periodicals, transect walks, and a concurrent forest-ecological study in the village. Results show that Mawlyngbna's forests provide important sources of livelihood benefits for the villagers. However, ecological disturbance and diversity varies among the different forest ownership types and forest-based livelihood benefits are inequitably distributed. Based on a bounded rationality approach, our analysis proposes a set of causal mechanisms that trace these observed social-ecological outcomes to the attributes of the resource system, resource units, actors and governance system. We analyse opportunities and constraints of interactions between the village, regional, and state levels. We discuss how Ostrom’s design principles for community-based resource governance inform the explanation of robustness but have a blind spot in explaining social equity. We report experiences made using the SES framework in empirical fieldwork. We conclude that mapping cross-level interactions in the SES framework needs conceptual refinement and that explaining social equity of forest governance needs theoretical advances.

Sēfer mešal haq-qadmônî : doś šprechṭ .. fon fil mînê mešālîm ...

[Isaak Ben-Salomon Ibn-Abi-Sahula]

Šini orṭlichi gišichṭn : ein šin naies bichlein gimochṭ for gros un klain ... eś iz oich niṭ mol giwezn gidrukṭ in unzr šprach ...

[Joseph Maarssen]

Sipure maʿaśiyot

Digitalisat der Ausg. Warszawa, 1863