Characterization of hepatic fatty acids in mice with reduced liver fat by ultra-short echo time (1)H-MRS at 14.1 T in vivo.

Alterations in the hepatic lipid content (HLC) and fatty acid composition are associated with disruptions in whole body metabolism, both in humans and in rodent models, and can be non-invasively assessed by (1)H-MRS in vivo. We used (1)H-MRS to characterize the hepatic fatty-acyl chains of healthy mice and to follow changes caused by streptozotocin (STZ) injection. Using STEAM at 14.1 T with an ultra-short TE of 2.8 ms, confounding effects from T2 relaxation and J-coupling were avoided, allowing for accurate estimations of the contribution of unsaturated (UFA), saturated (SFA), mono-unsaturated (MUFA) and poly-unsaturated (PUFA) fatty-acyl chains, number of double bonds, PU bonds and mean chain length. Compared with in vivo (1) H-MRS, high resolution NMR performed in vitro in hepatic lipid extracts reported longer fatty-acyl chains (18 versus 15 carbons) with a lower contribution from UFA (61 ± 1% versus 80 ± 5%) but a higher number of PU bonds per UFA (1.39 ± 0.03 versus 0.58 ± 0.08), driven by the presence of membrane species in the extracts. STZ injection caused a decrease of HLC (from 1.7 ± 0.3% to 0.7 ± 0.1%), an increase in the contribution of SFA (from 21 ± 2% to 45 ± 6%) and a reduction of the mean length (from 15 to 13 carbons) of cytosolic fatty-acyl chains. In addition, SFAs were also likely to have increased in membrane lipids of STZ-induced diabetic mice, along with a decrease of the mean chain length. These studies show the applicability of (1)H-MRS in vivo to monitor changes in the composition of the hepatic fatty-acyl chains in mice even when they exhibit reduced HLC, pointing to the value of this methodology to evaluate lipid-lowering interventions in the scope of metabolic disorders.

Responders to Wide-Pulse, High-Frequency Neuromuscular Electrical Stimulation Show Reduced Metabolic Demand: A 31P-MRS Study in Humans.

Conventional (CONV) neuromuscular electrical stimulation (NMES) (i.e., short pulse duration, low frequencies) induces a higher energetic response as compared to voluntary contractions (VOL). In contrast, wide-pulse, high-frequency (WPHF) NMES might elicit-at least in some subjects (i.e., responders)-a different motor unit recruitment compared to CONV that resembles the physiological muscle activation pattern of VOL. We therefore hypothesized that for these responder subjects, the metabolic demand of WPHF would be lower than CONV and comparable to VOL. 18 healthy subjects performed isometric plantar flexions at 10% of their maximal voluntary contraction force for CONV (25 Hz, 0.05 ms), WPHF (100 Hz, 1 ms) and VOL protocols. For each protocol, force time integral (FTI) was quantified and subjects were classified as responders and non-responders to WPHF based on k-means clustering analysis. Furthermore, a fatigue index based on FTI loss at the end of each protocol compared with the beginning of the protocol was calculated. Phosphocreatine depletion (ΔPCr) was assessed using 31P magnetic resonance spectroscopy. Responders developed four times higher FTI's during WPHF (99 ± 37 ×103 N.s) than non-responders (26 ± 12 ×103 N.s). For both responders and non-responders, CONV was metabolically more demanding than VOL when ΔPCr was expressed relative to the FTI. Only for the responder group, the ∆PCr/FTI ratio of WPHF (0.74 ± 0.19 M/N.s) was significantly lower compared to CONV (1.48 ± 0.46 M/N.s) but similar to VOL (0.65 ± 0.21 M/N.s). Moreover, the fatigue index was not different between WPHF (-16%) and CONV (-25%) for the responders. WPHF could therefore be considered as the less demanding NMES modality-at least in this subgroup of subjects-by possibly exhibiting a muscle activation pattern similar to VOL contractions.

In Vivo Longitudinal (1)H MRS Study of Transgenic Mouse Models of Prion Disease in the Hippocampus and Cerebellum at 14.1 T.

In vivo (1)H MR spectroscopy allows the non invasive characterization of brain metabolites and it has been used for studying brain metabolic changes in a wide range of neurodegenerative diseases. The prion diseases form a group of fatal neurodegenerative diseases, also described as transmissible spongiform encephalopathies. The mechanism by which prions elicit brain damage remains unclear and therefore different transgenic mouse models of prion disease were created. We performed an in vivo longitudinal (1)H MR spectroscopy study at 14.1 T with the aim to measure the neurochemical profile of Prnp -/- and PrPΔ32-121 mice in the hippocampus and cerebellum. Using high-field MR spectroscopy we were able to analyze in details the in vivo brain metabolites in Prnp -/- and PrPΔ32-121 mice. An increase of myo-inositol, glutamate and lactate concentrations with a decrease of N-acetylaspartate concentrations were observed providing additional information to the previous measurements.

Cabouret, Bernadette, Groslambert, Agnès, Wolff, Catherine (eds.), Visions de l’Occident romain. Hommages à Yann Le Bohec. Collection Études et Recherches sur l’Occident Romain, 2 vol. Paris, De Boccard 2012, págs. 959.

Este libro, en dos volúmenes, es un merecido homenaje al profesor Yann LE BOHEC (professeur émérite, Paris IV-La Sorbonne), jubilado forzosamente de la docencia universitaria en septiembre de 2011. La carrera investigadora del profesor Le Bohec que naturalmente continua en la actualidad ha tratado multitud de temas relacionados con el Imperio Romano, aunque deben ser destacadas en especial dos temáticas: el norte de África y el ejército romano. Y obviamente estos asuntos se ven también muy reflejados en los artículos de todos aquellos colegas y amigos que colaboran en el homenaje.

Cabouret, Bernadette, Groslambert, Agnès, Wolff, Catherine (eds.), Visions de l"Occident romain. Hommages à Yann Le Bohec. Collection Études et Recherches sur l"Occident Romain, 2 vol. Paris, De Boccard 2012, págs. 959. 27 x 17 cm. Prefacio de André Laronde ( ).

Este libro, en dos volúmenes, es un merecido homenaje al profesor Yann LE BOHEC (professeur émérite, Paris IV-La Sorbonne), jubilado forzosamente de la docencia universitaria en septiembre de 2011. La carrera investigadora del profesor Le Bohec que naturalmente continua en la actualidad ha tratado multitud de temas relacionados con el Imperio Romano, aunque deben ser destacadas en especial dos temáticas: el norte de África y el ejército romano. Y obviamente estos asuntos se ven también muy reflejados en los artículos de todos aquellos colegas y amigos que colaboran en el homenaje.

Red Riding Hood: Caperucita Roja, de Perrault a Catherine Hardwicke

El cuento de Caperucita Roja1 ha sobrevivido a través de los años gracias a su rico simbolismo por las imágenes de gran alcance que contiene. La joven niña con la capa roja que se encuentra con un lobo disfrazado de abuela es algo que golpea profundamente al receptor. El tema se ha estudiado desde numerosos puntos de vista; destaca el psicoanalista Bruno Bettelheim,2 que señala la caperuza que lleva la protagonista como símbolo de su entrada en la pubertad, asociando el color rojo con el ciclo menstrual. No todos los críticos están de acuerdo con este aspecto, aunque bastantes autores relacionan el cuento con el despertar de la sexualidad,la adolescencia y todo lo que conlleva. Perrault tampoco descuida tener en cuenta su advertencia de los riesgos en la etapa, sobre todo para las niñas románticas, en la moraleja final del relato.

Catherine M:n uusi alastomuus

Vastine Päivi Koiviston artikkeliin Totuus naisen seksuaalisuudesta? / Naistutkimus 3/2002.