Bioelectrical impedance spectroscopy to estimate fluid balance in critically ill patients

Fluid management is a crucial issue in intensive-care medicine. This study evaluated the feasibility and reproducibility of bioimpedance spectroscopy to measure body-water composition in critically ill patients, and compared fluid balance and daily changes in total body water (TBW) measured by bioimpedance. This observational study included 25 patients under mechanical ventilation. Fluid balance and bioimpedance measurements were recorded on 3 consecutive days. Whole-body bioimpedance spectroscopy was performed with exact or ideal body weights entered into the device, and with or without ICU monitoring. Reproducibility of bioimpedance spectroscopy was very good in all conditions despite ICU monitoring and mechanical ventilation. Bioimpedance measurements using an ideal body weight varied significantly, making the weighing procedure necessary. Comparison of fluid balance and daily changes in body weight provided the best correlation (ρ = 0.74; P < 0.0001). Daily changes in TBW were correlated with fluid balance (Spearman coefficient ρ = 0.31; P = 0.003) and this correlation was improved after exclusion of patients with a SOFA score >10 (ρ = 0.36; P = 0.05) and with extracorporeal circulation (ρ = 0.50; P = 0.005). Regardless of the technique used to estimate volume status, important limits of agreement were observed. Non-invasive determination of body-water composition using bioimpedance spectroscopy is feasible in critically ill patients but requires knowledge of the patient’s weight. The best method to assess volume status after fluid resuscitation and the value gained from information about body composition provided by bioimpedance techniques needs further evaluation.     

Kinetic modelling of in vitro cell-based assays to characterize non-specific bindings and ADME processes in a static and a perfused fluidic system

Recently, physiologically based perfusion in vitro systems have been developed to provide cell culture environment close to in vivo cell environment (e.g., fluidic conditions, organ interactions). In this work, we model and compare the fate of a chemical, benzo[a]pyrene (B[a]P), in a perfusion and a standard (static well-plate) system. These in vitro systems are composed of Caco-2 and HepG2 cells so as to mimic absorption across the small intestine and intestinal and hepatic metabolism. Compartmental models were developed and calibrated with B[a]P kinetics data in the culture medium to estimate the apparent permeability of Caco-2 cells, the in vitro biotransformation of B[a]P, as well as the different routes of loss by non-specific adsorption. Our results show that non-specific binding is the main process responsible for the depletion of B[a]P in the culture media: at steady state, only 40% and 24% of the total concentration of B[a]P are bioavailable in the static and perfused systems, respectively. We also showed that Caco-2 permeability in the perfused culture system is closer to in vivo conditions than the one obtained in the static system and that higher cellular metabolic activities are observed in static conditions. Perfused in vitro systems combined with kinetic modelling are promising tools for studying in vitro the different processes involved in the toxicokinetics of xenobiotics.     

Amoebicidal activity and chemical composition of Pterocaulon polystachyum (Asteraceae) essential oil

Acanthamoeba species are free-living amoebae that constitute an etiological agent of Acanthamoeba keratitis, an illness that may cause severe ocular inflammation and blindness and has a very difficult treatment. These molecules that are found in plants may be an alternative for the development of new drugs. Plants of the genus Pterocaulon (Asteraceae) are used in folk medicine as an antiseptic and antifungal agent. In this work, we analyzed Pterocaulon polystachyum essential oil and assessed its amoebicidal activity against Acanthamoeba polyphaga. The leaves of the fresh plant submitted to hydrodistillation yielded 0.15% (w/v) of essential oil that was analyzed by gas chromatography–mass spectrometry being E-sesquilavandulyl acetate as the major component, representing 43.8% of the oil. For the assessment of the amoebicidal activity, concentrations of 20, 10, 5, 2.5, and 1.25 mg/mL of essential oil were tested, being lethal to 100% of the A. polyphaga trophozoites at the concentrations of 10 and 20 mg/mL in 24 and 48 h. The cytotoxic effect of essential oil was also tested in mammalian cells using MTT assay. Amoebicidal activity results are in accordance with previous work in which the lipophilic compounds from this plant were active against Acanthamoeba castellanii. However, further studies with the major component of the essential oil will be carried out.     

Differential development of body equilibrium among littermates in the newborn rabbit

Interest is growing among psychobiologists and behavioral ecologists in the role of sibling relations in shaping individual development and life histories. In litters of domestic rabbits Oryctolagus cuniculus the heaviest pups at birth are more likely to survive the critical first postnatal week, they compete more effectively with littermates for milk and well-insulated positions in the litter huddle, and are the heaviest at weaning. Here we report that high birth weight pups are also better able to maintain body equilibrium. Testing pups' ability to maintain equilibrium when placed on a 15 degrees ramp for 2 min each day during the first postnatal week, we found that pups showed a continual daily improvement in their ability to maintain balance while moving on the ramp, rarely lost balance by postnatal day 8, and that heavier pups could maintain balance better and earlier than their lighter littermates. Better ability to maintain body equilibrium, however achieved, may help explain heavier pups' advantage in competing for vital resources such as milk and in gaining access to better-insulated positions in the litter huddle. It also provides further support for the usefulness of birth weight, not only as an absolute measure but also relative to the weight of other littermates, as a predictor of different developmental trajectories, behavioral and physiological, among same-age siblings in this mammal.     

Nasal delivery of P-gp substrates to the brain through the nose-brain pathway

The objective of this study was to evaluate in rats the potential utility of the nasal route to enhance central nervous system (CNS) delivery of drugs recognized by P-glycoprotein (P-gp). Well-known P-gp substrates verapamil and talinolol were perfused nasally or infused intravenously, and when plasma concentrations following intravenous infusion and nasal perfusion showed similar profiles. The concentration of verapamil in the brain after nasal perfusion was twice that after intravenous infusion. Although talinolol in the brain and the cerebrospinal fluid after i.v. infusion were below the detection limit, it was detected after nasal perfusion. When rats were treated with cyclosporin A, brain concentrations of verapamil after both administration modes were increased significantly, while those of talinolol were not significantly changed. Since the permeability of talinolol is low, talinolol in the brain which was transported directly from the nasal cavity has little chance of transport by P-gp localized in the apical membrane of cerebral microvessel endothelial cells. The potential for drug delivery utilizing the nose-CNS route was confirmed for P-gp substrates. The advantage of nasal delivery over i.v. delivery of talinolol to the brain was more significant than that of verapamil, suggesting that nasal administration is more useful strategy for the brain delivery of low-permeability P-gp substrates than the use of P-gp inhibitors.     

Diagnostic and surgical approach to an hourglass-shaped nasopalatine glioma in an infant

The authors report a case of glioma nasopalatine Multifoil in wallet, location-intra nasal and palatal left. The nasal glioma is a rare congenital malformation presenting as a nasal mass composed of neuroglial tissue heteropias resulting from an abnormality in embryonic development. It is a benign tumor that fits into the nosology of the masses of the midline. This abnormality arises primarily a diagnostic problem because often mistaken for a meningo-encephalocele or a nasal dermoid cyst. Localization nose and palate, an hourglass, is extremely rare if not exceptional; The computed tomography (CT) has enabled the accurate assessment of injury and has guided the choice of surgical technique. The resection was done successfully without recurrence. Histology examination of the surgical specimen confirmed the nature of astrocytic neuroglial tumor. The location of the tumor pedide palate to that of the left nostril is special and especially histological diagnosis of this congenital malformation.