Effect of indomethacin and adrenocorticotrophic hormone on renal function in man: An experimental model of inappropriate antidiuresis

Effect of indomethacin and adrenocorticotrophic hormone on renal function in man: An experimental model of inappropriate antidiuresis. The effect of prostaglandin synthesis inhibition on basal and ACTH-stimulated adrenal and renal function was investigated in normai volunteers. Data were collected during control and experimental study periods (13 days each). Adrenocorticotrophic hormone (Cosyntropin, 80 U/day) was administered i.v. on days 8 and 9 of each period. Indomethacin (150 mg/day) was given on days 5 through 13 of the experimental period. The subjects ate a constant diet containing 9 mEq of sodium, 100 mEq of potassium, and 2,500 ml of fluid daily. Indomethacin markedly inhibited urinary PGE excretion and plasma PGE concentration. The effect of ACTH alone as compared to the effect of ACTH and indomethacin showed: plasma sodium concentration, 139 ± 1 vs. 131 ± 3 mEg/liter (P < 0.01, mean ± SEM); plasma osmolality, 287 ± 3 vs. 270 ± 3 mOsm/liter (P < 0.01); free water clearance, 97 ± 66 vs. -1100 ± 380 ml/24hr (P < 0.01); urine volume, 2,000 ± 60 vs. 950 ± 200 ml/day (P < 0.01); and urine osmolality 282 ± 12 vs. 720 ± 144 mOsm/liter (P < 0.01). We conclude that the effects of ACTH and prostaglandin synthesis inhibition interact to result in inappropriate antidiuresis.Effet de l'indométhacine et de l'hormone adrénocorticotrope sur la fonction rénale chez l'homme: Un modèle expérimental d'antidiurèse inappropriée. L'effet de l'inhibition de la synthèse de prostaglandine sur la fonction surrénalienne basale et stimulée par l'ACTH et sur la fonction rénale a été étudié chez des sujets normaux volontaires. Les résultats ont été obtenus au cours de périodes contrôles et expérimentales de 13 jours chacune. De l'hormone adrénocorticotrope (Cosyntropin) a été administrée par voie i.v. les 8ème et 9ème jours de chaque période à raison de 80 U par jour. L'indométhacine, 150 mg/jour, a été donnée du 8ème au 13ème jour de la période expérimentale. Les sujets ont été soumis à un régime constant contenant 9 mEq de sodium, 100 mEq de potassium, et 2,500 ml de liquide par jour. L'indométhacine a fortement inhibé l'excrétion urinaire de PGE et abaissé la concentration plasmatique de PGE. L'effet de l'ACTH seul comparé à l'effet de l'ACTH associé à l'indométhacine a montré: une concentration plasmatique de sodium de 139 ± 1 vs. 131 ± 3 mEq/litre (P < 0,01) moyenne et SEM); une osmolalité plasmatique de 287 ± 3 vs. 270 ± 3 mOsm/litre (P < 0,01); une clearance de l'eau libre de 97 ± 66 vs. - 1100 ± 380 ml/24 hr (P < 0,01); un débit urinaire de 2,000 ± 60 vs. 950 ± 200 ml/jour (P < 0,01); et une osmolalité urinaire de 282 ± 12 vs. 720 ± 144 mOsm/litre (P < 0,01). Nous considérons que les effets de l'ACTH et de l'inhibition de la synthèse de prostaglandine se combinent pour déterminer une antidiurése inappropriée

Investigation of continuous-time quantum walk by using Krylov subspace-Lanczos algorithm

In papers\cite{js,jsa}, the amplitudes of continuous-time quantum walk on graphs possessing quantum decomposition (QD graphs) have been calculated by a new method based on spectral distribution associated to their adjacency matrix. Here in this paper, it is shown that the continuous-time quantum walk on any arbitrary graph can be investigated by spectral distribution method, simply by using Krylov subspace-Lanczos algorithm to generate orthonormal bases of Hilbert space of quantum walk isomorphic to orthogonal polynomials. Also new type of graphs possessing generalized quantum decomposition have been introduced, where this is achieved simply by relaxing some of the constrains imposed on QD graphs and it is shown that both in QD and GQD graphs, the unit vectors of strata are identical with the orthonormal basis produced by Lanczos algorithm. Moreover, it is shown that probability amplitude of observing walk at a given vertex is proportional to its coefficient in the corresponding unit vector of its stratum, and it can be written in terms of the amplitude of its stratum. Finally the capability of Lanczos-based algorithm for evaluation of walk on arbitrary graphs (GQD or non-QD types), has been tested by calculating the probability amplitudes of quantum walk on some interesting finite (infinite) graph of GQD type and finite (infinite) path graph of non-GQD type, where the asymptotic behavior of the probability amplitudes at infinite limit of number of vertices, are in agreement with those of central limit theorem of Ref.\cite{nko}.Comment: 29 pages, 4 figure

R-PEP-27, a Potent Renin Inhibitor, Decreases Plasma Angiotensin II and Blood Pressure in Normal Volunteers

The hemodynamic and humoral effects of the specific human renin inhibitor R-PEP-27 were studied in six normal human subjects on low and high sodium intake diets. An intravenous infusion of R-PEP-27 (0.5 to 16 μg/min/kg body wt) reduced blood pressure in a dose-dependent fashion; the mean arterial blood pressure at the end of the infusion fell from 128 ± 4/83 ± 4 to 119 ± 3/71 ± 3 mm Hg (mean ± SEM) (P < .01) during the low sodium intake diet. R-PEP-27 had no effect on blood pressure during the high sodium intake diet. R-PEP-27 significantly reduced plasma angiotensin II and aldosterone concentrations. The temporal response to R-PEP-27 suggests that it is a shortlived although highly potent competitive inhibitor of renin; this peptide is a valuable and specific physiologic probe of the renin-angiotensin system. Am J Hypertens 1994;7:295-30

Localized states in strong magnetic field: resonant scattering and the Dicke effect

We study the energy spectrum of a system of localized states coupled to a 2D electron gas in strong magnetic field. If the energy levels of localized states are close to the electron energy in the plane, the system exhibits a kind of collective behavior analogous to the Dicke effect in optics. The latter manifests itself in ``trapping'' of electronic states by localized states. At the same time, the electronic density of states develops a gap near the resonance. The gap and the trapping of states appear to be complementary and reflect an intimate relation between the resonant scattering and the Dicke effect. We reveal this relation by presenting the exact solution of the problem for the lowest Landau level. In particular, we show that in the absence of disorder the system undergoes a phase transition at some critical concentration of localized states.Comment: 28 pages + 9 fig

Type VI secretion: a beginner's guide

Type VI secretion is a newly described mechanism for protein transport across the cell envelope of Gram-negative bacteria. Components that have been partially characterised include an IcmF homologue, the ATPase ClpV, a regulatory FHA domain protein and the secreted VgrG and Hcp proteins. Type VI secretion is clearly a key virulence factor for some important pathogenic bacteria and has been implicated in the translocation of a potential effector protein into eukaryotic cells by at least one organism (Vibrio cholerae). However, type VI secretion systems (T6SSs) are widespread in nature and not confined to known pathogens. In accordance with the general rule that the expression of protein secretion systems is tightly regulated, expression of type VI secretion is controlled at both transcriptional and post-transcriptional levels