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Medical Sciences	50%

Selected Abstracts

Effect of elevated homocysteine on cardiac neural crest migration in vitro

DEVELOPMENTAL DYNAMICS, Issue 2 2002
Philip R. Brauer
Abstract A positive correlation between elevated maternal homocysteine (Hcys) and an increased risk of neural tube, craniofacial, and cardiac defects is well known. Studies suggest Hcys perturbs neural crest (NC) development and may involve N-methyl-D-aspartate (NMDA) receptors (Rosenquist et al., 1999). However, there is no direct evidence that Hcys alters NC cell behavior. Here, we evaluated the effect of Hcys on cardiac NC cell migratory behavior in vitro. Neural tube segments from chick embryos treated in ovo with or without Hcys were placed in culture and the migratory behavior of emigrating NC cells was monitored. Hcys significantly increased in vitro NC cell motility at all embryonic stages examined. NC cell surface area and perimeter were also increased. However, the relative distance NC cells migrated from their original starting point only increased in NC cells treated in ovo at stage 6 or at the time neural tube segments were cultured. Cysteine had no effect. NMDA mimicked Hcys' effect on NC motility and migration distance but had no effect on cell area or perimeter. The noncompetitive inhibitor of NMDA receptors, MK801+, significantly inhibited NC cell motility, reduced migration distance, and also blocked the effects of NMDA and Hcys on NC motility and migratory distance in vitro. A monoclonal antibody directed against the NMDA receptor immunostained NC cells in vitro and, in western blots, bound a single protein with the appropriate molecular weight for the NMDA receptor in NC cell lysates. These data are consistent with the hypothesis that a Hcys-sensitive NMDA-like receptor is expressed by early emigrating NC cells or their precursors, which is important in mediating their migratory behavior. Perturbation of this receptor may be related to some of the teratogenic effects observed with elevated Hcys. © 2002 Wiley-Liss, Inc. [source]

A simplified technique for diagnostic and surgical arthroscopy of the shoulder joint in the dog

JOURNAL OF SMALL ANIMAL PRACTICE, Issue 1 2002
F. M. Martini
A modified technique is presented for surgical and diagnostic arthroscopy of the shoulder joint in the dog. The technique involves access to the joint through two points only; one was created in place of the drainage needle-cannula, which was replaced with a portal, while the second was located more caudally compared with previous techniques. Using a changing guide rod system the two portals are completely interchangeable in order to perform easier arthroscopic surgery either in the cranial or caudal aspect of the joint. The presence of only one portal caudal to the lateral collateral ligament allows more freedom of movement and avoids interference between the arthroscope and the instruments. The modified procedure was performed on 33 joints affected by osteochondritis dissecans or tenoligament diseases and facilitated straightforward diagnostic examinations, and simple and rapid surgical procedures. [source]

2D Slurry Bubble Column Hydrodynamic Phenomena Clarified with a 3D Gas,Liquid Model

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3-4 2003
Jeroen H. J. Kluytmans
Abstract The gas hold-up in a 2D bubble column is modelled using a 3D gas hold-up model. The influence of the scale of 2D bubble columns on several parameters, for instance, transition gas hold-up, transition gas velocity, and bubble rise velocities, is investigated and related to 3D bubble columns. By adapting the rise velocity of the large bubbles of an existing 3D bubble column model (Krishna et al., 2001a), the gas hold-up in both the homogeneous and the heterogeneous regime can be described satisfactorily. By adjusting the transition points only, it is also possible to describe the gas hold-up in systems containing small amounts of carbon particles and electrolyte. The smallest dimension of the 2D slurry bubble column, the column thickness, influences the location of the regime transition point. In the heterogeneous regime, however, it is only the largest column dimension, the column width, that influences the gas hold-up. These observations together enable proper 2D/3D bubble column comparison in future studies. Dans cette étude, la rétention de gaz dans une colonne à bulles en 2D est modélisée à l'aide d'un modèle de rétention de gaz en 3D. L'influence de l'échelle des colonnes à bulles 2D sur plusieurs paramètres, comme la rétention de gaz de transition, la vitesse de gaz de transition et les vitesses de montée des bulles, est étudiée et reliée aux colonnes à bulles 3D. On montre qu'en adaptant la vitesse de montée des bulles larges fournie par un modèle de colonnes à bulles 3D existant (Krishna et al., 2001a), la rétention de gaz tant en régime homogène qu'hétérogène peut être décrite de manière satisfaisante. En ajustant seulement les points de transition, il est également possible de décrire la rétention de gaz dans des systèmes contenant de petites quantités de particules de carbone et d'électrolyte. On a trouvé que la plus petite dimension de la colonne à bulles à suspensions 2D, soit l'épaisseur de la colonne, influence la position du point de transition de régime. Cependant, dans le régime hétérogène, c'est seulement la plus grande dimension de la colonne, soit la largeur de la colonne, qui influence la rétention de gaz. Toutes ces observations vont permettre des comparaisons adéquates des colonnes 2D et 3D dans les prochaines études. [source]

Low-carbohydrate (low & high-fat) versus high-carbohydrate low-fat diets in the treatment of obesity in adolescents

ACTA PAEDIATRICA, Issue 2 2009
S Demol
Abstract Aim: To compare the impact of low-carbohydrate diets of different fat content to high-carbohydrate low-fat diet on weight and metabolic parameters in obese adolescents. Methods: Fifty-five patients aged 12,18 years with a body mass index (BMI) above the 95th percentile were randomly allocated to one of three isoenergetic diet regimens. Anthropometric and metabolic measurements were taken after overnight fast, at baseline, after the 12-week intervention and after nine month of follow-up. Results: No significant differences were found among the groups in changes in BMI, BMI-percentile, fat percentage, or metabolic markers at the end of the intervention and at the end of follow-up. Insulin level and homeostasis model assessment (HOMA) level decreased significantly at both time points only in the two low carbohydrate diet groups. Conclusion: All diet regimens are associated with a significant reduction in BMI and improvement of some metabolic parameters in obese adolescents. Low-carbohydrate diets apparently have no advantage over high-carbohydrate low-fat diets. The significant drop in insulin level and HOMA in the low carbohydrate diet groups is noteworthy given the increasing frequency of type-2 diabetes as part of metabolic syndrome in children and youth. The impact of low carbohydrate diets in obese and insulin-resistant youth warrants further investigation. [source]