Up-regulation of hypoxia-inducible factor-1alpha is not sufficient for hypoxic/anoxic p53 induction

Oxygen-deprived regions of a solid tumor can induce tumor suppressor p53 expression and hence select for p53-mutant tumor cells with diminished apoptotic potential. It has been proposed that the hypoxia-inducible factor-1 (HIF-1) alpha subunit binds to p53 and protects it from proteasomal degradation. However, we found that hypoxic conditions that strongly induce HIF-1-dependent endogenous gene expression as well as HIF-1alpha protein neither induce p53-dependent gene expression nor p53 protein. The iron chelator deferoxamine induced both HIF-1alpha and p53, but p53 up-regulation could still be detected in HIF-1alpha-deficient cells, suggesting that mechanisms other than HIF-1alpha activation contribute to oxygen-regulated p53 induction.     

Optimal erythropoietin expression in human hepatoma cell lines requires activation of multiple signalling pathways

The Drosophila wing is divided into anterior and posterior compartments, the latter characterized by the expression of the engrailed gene. A comparative analysis is presented here, and suggests that a primary conserved role of engrailed is to drive growth of limbs along the proximo-distal axis. The Apical Ectodermal Ridge in vertebrate limbs resembles the Antero/ Posterior compartment boundary in fly wings, particularly in molecular aspects. Multiple evidence suggests that the fly wing Antero/Posterior boundary is not the result of differential cell affinities between all anterior and posterior cells, but responds to the area of cell communication between anterior and posterior compartments. Arguments are presented here to support the notion that the compartment boundary is a consequence of decapentaplegic function in the control of growth. Patterning, on the other hand, requires the participation of several genes, among which are engrailed, invected and hedgehog. Finally, regulatory interactions between en/En-1 and hh/Shh may be significant in the context of morphogenetic regulation during normal development.     

Cue integration across study tasks and direct and indirect retrieval instructions: Implications for the study of retrieval processes.

In 3 experiments, the ability of a specific model of information integration—the fuzzy logical model of perception (FLMP; D. W. Massaro, 1987; D. W. Massaro et al, see record 1991-17539-001)—to account for retrieval performance across a range of study and test conditions was examined. Results show that the FLMP's relative goodness rule is capable of describing performance in all conditions; in addition, changes in model parameters tracked changes in cued-recall performance in meaningful and interpretable ways, providing a validity test for the model. The model and the experimental paradigm used to test the model are reviewed with respect to their assumptions, and directions important for their use in the study of retrieval processes are outlined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Results of proximal tibial osteotomy. The effects of tibiofemoral angle, stance-phase flexion-extension, and medial-plateau force

Forty-eight knees were evaluated after proximal tibial osteotomy, performed for varus deformity to determine the desired amount of correction of the deformity, the effect of osteotomy on knee motion during gait and one medial-plateau force during standing, and the relationships between these factors and the result. Correction of the tibiofemoral angle to 5 degrees of genu valgum or more produced the best and most lasting results. Stance-phase flexion-extension increased the rotation decreased in knees with good results while the other gait parameters were not significantly changed. Medial-plateau force was decreased by successful tibial osteotomy. The knees with the best and most lasting results had 7 degrees of stance-phase flexion-extension or more during walking and either a valgus tibiofemoral angle of 5 degrees or more or a medial-plateau force of 50 per cent of body weight or less.     

Secreting paragangliomas of the organ of Zuckerkandl. A report on two cases (author's transl)

The authors describe two cases of secreting paragangliomas of the organ of Zuckerkandl, beinging the number of known cases to 78. They underline the interest of arteriographic and phlebographic explorations which define more accurately the origin and spread of these tumours.     

Correlation entre les courbes courant-tension et la morphologie des dépôts électrolytiques d'étain

Résumé En contrÔlant le transport de matière par diffusion au sein de l'électrolyte au moyen d'une électrode à disque tournant, on étudie le mécanisme de lélectrocristallisation de l'étain en milieu phénolsulfonique. Les courbes courant-tension stationnaires et les diagrammes d'impédance peuvent s'expliquer par la coexistence d'au moins trois espèces adsorbées à l'interface métal-electrolyte. L'apparition des trois variétés morphologiques (spongieuse, compacte, puis dendritique) de dépÔt observées lorsqu'on augmente la densité de courant suggère, d'une manière analogue à l'électrocristallisation du zinc, l'intervention d'un processus autocatalytique dans le mécanisme réactionnel de décharge des ions Sn²⁺ et son couplage avec la diffusion superficielle d'adions du type Sn _ads ⁺ . La compétition entre l'adsorption d'hydrogène, capable d'inhiber la décharge des ions Sn²⁺, et ce processus autocatalytique explique que, dans les conditions stationnaires, la courbe courant-tension soit parallèle à l'axe des courants dans une certaine gamme de densités de courant.L'addition de dihydroxydiphenylsulfone dans l'électrolyte, qui élargit le domaine des densités de courant intermédiaires où le dépÔt reste compact, modifie la cinétique de l'électrocristallisation en ayant pour effet de réduire l'importance relative du processus autocatalytique dans le mécanisme réactionnel.

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The mechanism of the electrocrystallization of tin in a phenolsulphonic bath is studied by using a rotating disc electrode. The current-voltage curves plotted under steady-state conditions and the impedance diagrams can be explained by the coexistence of at least three adsorbed species at the metal-electrolyte interface. The three kinds of deposit morphology (spongy, compact, and dendritic) which are observed with increasing current density suggests, as in the case of zinc electrocrystallization, the coupling of an autocatalytic step occurring at the interface with the surface diffusion of adions such as Sn _ads ⁺ . The competition between this autocatalytic step and the hydrogen adsorption, which is able to inhibit the discharge of Sn²⁺ ions, explains why the steady-state current-voltage curves are parallel to the current axis in a certain range of current density.With small amounts of dihydroxydiphenylsulphone in the electrolyte, the range of current density leading to compact deposits is widened. It is shown that the additive changes the coupling of the processes taking place at the interface and seems to decrease the importance of the autocatalytic step in the reaction mechanism.

     

Clinical and biochemical studies in an American child with sialuria

Sialuria is a rare inborn error of sialic acid (NeuAc) metabolism resulting from failure of CMP-NeuAc to adequately feedback inhibit the rate-limiting enzyme in sialic acid synthesis, UDP N-acetylglucosamine (UDP-GlcNAc) 2-epimerase. We describe the fourth reported sialuria patient, T.W., whose clinical features include developmental delay, coarse facies, and massive urinary excretion of sialic acid. Biochemical studies of T.W. fibroblasts revealed a 200-fold increase in free NeuAc content compared with normal. Bound NeuAc was only slightly elevated. The free NeuAc was predominantly in the cytosol fraction of fibroblasts after differential centrifugation, with only 4% of the free NeuAc content in other (nuclear, granular, and microsomal) cellular compartments. CMP-NeuAc inhibited UDP-GlcNAc 2-epimerase by 80% in normal fibroblasts but inhibited the epimerase of T.W. (sialuria) cells by only 13%. Cytidine feeding of sialuria fibroblasts decreased the intracellular free NeuAc content by 47%; this was accompanied by a fourfold increase in CMP-NeuAc, which may be sufficient to feedback inhibit the mutant epimerase and reduce free NeuAc production. Cytoplasmic pH was determined by the pH sensitive fluorescent indicator 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, pentaacetoxymethylester (BCECF/AM) using the H+ equilibration method. The intracellular pH of sialuria fibroblasts, 7.18 +/- 0.04, was not found to be significantly different from that of normal cells (7.19 +/- 0.08).     

Design and fabrication of monolithic optical spot size transformers(MOSTs) for highly efficient fiber-chip coupling

A novel type of monolithic optical spot size transformer realized in the InP/InGaAsP material system combines many desirable features like high fiber-chip coupling efficiency, large spot size transformation, high tolerances for fiber alignment, simple fabrication, and straightforward integrability with other devices. The spot size transformation is accomplished by two waveguide sections tapered in the vertical and lateral directions, respectively. We discuss design issues, describe the fabrication process, give experimental results, and present the monolithic integration of the spot size transformers with a current controlled directional coupler switch