Oleate prevents saturated-fatty-acid-induced ER stress, inflammation and insulin resistance in skeletal muscle cells through an AMPK-dependent mechanism.

AIMS/HYPOTHESIS: Although the substitution of saturated fatty acids with oleate has been recommended in the management of type 2 diabetes mellitus, the mechanisms by which oleate improves insulin resistance in skeletal muscle cells are not completely known. Here, we examined whether oleate, through activation of AMP-activated protein kinase (AMPK), prevented palmitate-induced endoplasmic reticulum (ER) stress, which is involved in the link between lipid-induced inflammation and insulin resistance. METHODS: Studies were conducted in mouse C2C12 myotubes and in the human myogenic cell line LHCN-M2. To analyse the involvement of AMPK, activators and inhibitors of this kinase and overexpression of a dominant negative AMPK construct (K45R) were used. RESULTS: Palmitate increased the levels of ER stress markers, whereas oleate did not. In palmitate-exposed cells incubated with a lower concentration of oleate, the effects of palmitate were prevented. The induction of ER stress markers by palmitate was prevented by the presence of the AMPK activators AICAR and A-769662. Moreover, the ability of oleate to prevent palmitate-induced ER stress and inflammation (nuclear factor-kappa B [NF-κB] DNA-binding activity and expression and secretion of IL6) as well as insulin-stimulated Akt phosphorylation and 2-deoxyglucose uptake was reversed in the presence of the AMPK inhibitor compound C or by overexpression of a dominant negative AMPK construct. Finally, palmitate reduced phospho-AMPK levels, whereas this was not observed in oleate-exposed cells or in palmitate-exposed cells supplemented with oleate. CONCLUSIONS/INTERPRETATION: Overall, these findings indicate that oleate prevents ER stress, inflammation and insulin resistance in palmitate-exposed skeletal muscle cells by activating AMPK.

Síndrome de hipoventilación central congénita y su continuidad asistencial en atención primaria / Congenital central hypoventilation syndrome and continuity in Primary Health Care

Los avances científicos y las mejoras socioeconómicas han repercutido en los avances técnicos y terapéuticos y cambiado el mapa de actuación del pediatra y de la pediatría. Hoy en día, enfermedades que antes resultaban letales han visto modificada su evolución y la supervivencia de los pacientes ha aumentado, dando paso a situaciones de cronicidad. Así, las patologías que sólo tenían un abordaje hospitalario pueden ahora tratarse en atención primaria, lo cual precisa, además de una familia implicada y capaz de ocuparse de los cuidados necesarios, disponer de recursos materiales y de profesionales dispuestos a asumir dicha tarea. Presentamos el caso de una niña de 19 meses con síndrome de hipoventilación central congénita (SHCC) –enfermedad probablemente infradiagnosticada y caracterizada por hipoventilación durante el sueño– que necesita ventilación asistida a través de traqueostomía, con alimentación enteral a débito continuo por gastrostomía, y en la que al existir la posibilidad de traslado a una vivienda próxima al hospital se plantea el alta hospitalaria. Se traza un plan de actuación y coordinación entre el hospital, el centro de salud, los padres, el distrito sanitario, la gerencia del hospital y el servicio de emergencias. Además, se protocoliza la actuación a seguir en atención primaria, en la que se implica a otros profesionales del centro de salud: pediatra, enfermera y trabajador social. En este artículo, se comunica la experiencia llevada a cabo tras 9 meses de seguimiento (AU)

The scientific advances and socio-economic improvements have had an impact on technical and therapeutic advances, changing the chart of the paediatrician’s and pediatrics performance. Diseases that used to be lethal before have changed their evolution at present with an increase in the children´s survival, leaving them in chronic situations. Thus, diseases that previously only had a hospital boarding can now be treated in Primary Health Care, which would require material resources and professionals willing to undertake this task, beside an involved family, able to deal with the necessary cares. We present a congenital central hypoventilation syndrome, a disease probably under diagnosed and characterized by hypoventilation during sleep, in a 19-months girl who needs assisted ventilation during sleep through tracheotomy, with continuous debit enteral nutrition by gastrostomy, and considering the possibility of moving her to a house close to the hospital, discharge is set out. An action plan and coordination between Hospital Health Center, parents, Health District, Hospital Management and Emergencies is drawn up. The steps to be taken are protocolized at the Primary Health Care, in which the rest of the professionals of the Health Centre is involved in her assistance and with the express management by the appointed pediatrician, nurse and social worker. The experience carried out after 9months of follow-up is informed (AU)

Binding affinity properties of dendritic glycosides based on a beta-cyclodextrin core toward guest molecules and concanavalin A.

The inclusion behavior and concanavalin A binding properties of hepta-antennated and newly synthesized tetradeca-antennated C-6-branched mannopyranosyl and glucopyrannosyl cyclomaltoheptaose (beta-cyclodextrin) derivatives have been evaluated by isothermal titration microcalorimetry and enzyme-linked lectin assay (ELLA), respectively. The synthesis of three first-order dendrimers based on a beta-cyclodextrin core containing 14 1-thio-beta-D-glucose, 1-thio-beta-mannose, and 1-thio-beta-rhamnose residues was performed following a convergent approach and involving (1) preparation of a thiolated bis-branched glycoside building block and (2) attachment of the building block onto heptakis(6-deoxy-6-iodo)-beta-cyclodextrin. Calorimetric titrations performed at 25 degrees C in buffered aqueous solution (pH 7.4) gave the affinity constants and the thermodynamic parameters for the inclusion complex formation of these beta-cyclodextrin derivatives with guests sodium 8-anilino-1-naphthalensulfonate (ANS) and 2-naphthalenesulfonate. The host capability of the persubstituted beta-cyclodextrins decreased with respect to the native beta-CD when sodium 2-naphthalenesulfonate was used as a guest and improved when ANS was used as a guest molecule. Heptavalent mannoclusters based on beta-CD cores enhance the lectin binding affinity due to the cluster effect; however, the increase of the valency from 7 to 14 ligands did not contribute to the improvement of the concanavalin A binding affinity. In addition, the synthesized hyperbranched mannoCDs lost completely the capability as a host molecules.

A double-blind, placebo-controlled study of the use of amphetamine in the treatment of aphasia.

BACKGROUND AND PURPOSE: A number of studies suggest that drugs which increase the release of norepinephrine promote recovery when administered late (days to weeks) after brain injury in animals. A small number of clinical studies have investigated the effects of the noradrenergic agonist dextroamphetamine in patients recovering from motor deficits following stroke. To determine whether these findings extend to communication deficits subsequent to stroke, we administered dextroamphetamine, paired with speech/language therapy, to patients with aphasia. METHODS: In a prospective, double-blind study, 21 aphasic patients with an acute nonhemorrhagic infarction were randomly assigned to receive either 10 mg dextroamphetamine or a placebo. Patients were entered between days 16 and 45 after onset and were treated on a 3-day/4-day schedule for 10 sessions. Thirty minutes after drug/placebo administration, subjects received a 1-hour session of speech/language therapy. The Porch Index of Communicative Ability was used at baseline, at 1 week off the drug, and at 6 months after onset as the dependent language measure. RESULTS: Although there were no differences between the drug and placebo groups before treatment (P=0.807), by 1 week after the 10 drug treatments ended there was a significant difference in gain scores between the groups (P=0.0153), with the greater gain in the dextroamphetamine group. The difference was still significant when corrected for initial aphasia severity and age. At the 6-month follow-up, the difference in gain scores between the groups had increased; however, the difference was not significant (P=0.0482) after correction for multiple comparisons. CONCLUSIONS: Administration of dextroamphetamine paired with 10 1-hour sessions of speech/language therapy facilitated recovery from aphasia in a small group of patients in the subacute period after stroke. Neuromodulation with dextroamphetamine, and perhaps other drugs that increase central nervous system noradrenaline levels, may facilitate recovery when paired with focused behavioral treatment.

Thermodynamic analysis of the binding of glutathione to glutathione S-transferase over a range of temperatures.

The binding properties of a glutathione S-transferase (EC 2.5.1.18) from Schistosoma japonicum to substrate glutathione (GSH) has been investigated by intrinsic fluorescence and isothermal titration calorimetry (ITC) at pH 6.5 over a temperature range of 15-30 degrees C. Calorimetric measurements in various buffer systems with different ionization heats suggest that protons are released during the binding of GSH at pH 6.5. We have also studied the effect of pH on the thermodynamics of GSH-GST interaction. The behaviour shown at different pHs indicates that at least three groups must participate in the exchange of protons. Fluorimetric and calorimetric measurements indicate that GSH binds to two sites in the dimer of 26-kDa glutathione S-transferase from Schistosoma japonicum (SjGST). On the other hand, noncooperativity for substrate binding to SjGST was detected over a temperature range of 15-30 degrees C. Among thermodynamic parameters, whereas DeltaG degrees remains practically invariant as a function of temperature, DeltaH and DeltaS degrees both decrease with an increase in temperature. While the binding is enthalpically favorable at all temperatures studied, at temperatures below 25 degrees C, DeltaG degrees is also favoured by entropic contributions. As the temperature increases, the entropic contributions progressively decrease, attaining a value of zero at 24.3 degrees C, and then becoming unfavorable. During this transition, the enthalpic contributions become progressively favorable, resulting in an enthalpy-entropy compensation. The temperature dependence of the enthalpy change yields the heat capacity change (DeltaCp degrees ) of -0.238 +/- 0.04 kcal per K per mol of GSH bound.

A calorimetric study of the binding of S-alkylglutathiones to glutathione S-transferase.

The binding of three competitive glutathione analogue inhibitors (S-alkylglutathione derivatives) to glutathione S-transferase from Schistosoma japonicum, SjGST, has been investigated by isothermal titration microcalorimetry at pH 6.5 over a temperature range of 15--30 degrees C. Calorimetric measurements in various buffer systems with different ionization heats suggest that no protons are exchanged during the binding of S-alkylglutathione derivatives. Thus, at pH 6.5, the protons released during the binding of substrate may be from its thiol group. Calorimetric analyses show that S-methyl-, S-butyl-, and S-octylglutathione bind to two equal and independent sites in the dimer of SjGST. The affinity of these inhibitors to SjGST is greater as the number of methylene groups in the hydrocarbon side chain increases. In all cases studied, Delta G(0) remains invariant as a function of temperature, while Delta H(b) and Delta S(0) both decrease as the temperature increases. The binding of three S-alkylglutathione derivatives to the enzyme is enthalpically favourable at all temperatures studied. The temperature dependence of the enthalpy change yields negative heat capacity changes, which become less negative as the length of the side chain increases.

Enthalpy of captopril-angiotensin I-converting enzyme binding.

High-sensitivity titration calorimetry is used to measure changes in enthalpy, heat capacity and protonation for the binding of captopril to the angiotensin I-converting enzyme (ACE; EC 3.4.15.1). The affinity of ACE to captopril is high and changes slightly with the pH, because the number of protons linked to binding is low. The determination of the enthalpy change at different pH values suggests that the protonated group in the captopril-ACE complex exhibits a heat protonation of approximately -30 kJ/mol. This value agrees with the protonation of an imidazole group. The residues which may become protonated in the complex could be two histidines existing in two active sites, which are joined to the amino acids coordinated to Zn2+. Calorimetric measurements indicate that captopril binds to two sites in the monomer of ACE, this binding being enthalpically unfavorable and being dominated by a large positive entropy change. Thus, binding is favored by both electrostatic and hydrophobic interactions. The temperature dependence of the free energy of binding deltaG degrees is weak because of the enthalpy-entropy compensation caused by a large heat capacity change, deltaCp =-4.3+/-0.1 kJ/K/mol of monomeric ACE. The strong favorable binding entropy and the negative deltaCp indicate both a large contribution to binding due to hydrophobic effects, which seem to originate from dehydration of the ligand-protein interface, and slight conformational changes in the vicinity of the active sites.

Simulation of compartmental models for kinetic data from a positron emission tomograph.

Linear compartmental models are used to describe the disposition of radio-labelled compounds in regions of interest in the mammalian body, based on a time sequence of measurements from a positron emission tomograph (PET). In this paper we show how closed form solutions for the model equations have been incorporated into a computer program for simulation and parameter estimation. A typical PET data example is included to illustrate the implementation and compare the closed form method with a numerical ode solution method.

Heavy isotope-labeling study of the metabolism of monomeric and tetrameric acetylcholinesterase forms in the murine neuronal-like T 28 hybrid cell line.

We have used the method of heavy isotope labeling to study the metabolic turnover of acetylcholinesterase forms in the neuroblastoma-derived T 28 hybrid cells in their differentiated state. These cells contain mostly G1 and G4 forms, together with a small proportion of G2, and secrete all these forms into the culture medium. The cells maintained constant and equal levels of acetylcholinesterase, with the same proportions of molecular forms, in a medium containing heavy isotope-labeled amino acids and in a control light medium of similar composition. In addition, they secreted acetylcholinesterase at the same rate in both media. After transfer of the cells into the heavy medium, heavy isotope-labeled acetylcholinesterase molecules progressively replace preexisting light molecules. We analyzed heavy and light components of acetylcholinesterase for each of the two major G1 and G4 forms, by reconstructing the pattern obtained in sucrose gradient differential sedimentation, using combinations of weighted elementary distributions. Heavy molecules were detected in cellular extracts after about 30 min for G1 and 3 h for G4. Both heavy forms also appeared in the medium after a lag of about 3 h. The cellular complement of G1 was renewed much faster than that of G4, the levels of the light forms being reduced to 50% of the original level after 3.5 and 40 h, respectively. Each of these forms appeared to consist of several metabolic pools, and we present simplified models which describe their possible relationships.