Establishment of mouse and rat hepatoma cell clones showing stable expression of rabbit cytochrome P450 IA2

AbstractCytochrome P450 IA2, a liver-specific member of the 3-methylcholanthrene-inducible family, is never detected in established cell lines. With the aim of isolating cells stably producing this protein, we have used rat and mouse hepatoma cells as recipients in transfection experiments involving rabbit cytochrome P450 IA2 cDNA. We report here the isolation of five hepatoma cell clones expressing functional P450 IA2. The level of expression is comparable to that found in COS cells transiently transformed by other P450 cDNAs. It ranges between 0.4 and 1.6 pmol P450 IA2/mg total cell protein

Combining high dose therapy, bilateral motor priming, and vagus nerve stimulation to treat the hemiparetic upper limb in chronic stroke survivors: a perspective on enhancing recovery

Stroke is a leading cause of disability worldwide and upper limb hemiparesis is the most common post-stroke disability. Recent studies suggest that clinically significant motor recovery is possible in chronic stroke survivors with severe impairment of the upper limb. Three promising strategies that have been investigated are (1) high dose rehabilitation therapy (2) bilateral motor priming and (3) vagus nerve stimulation. We propose that the future of effective and efficient upper limb rehabilitation will likely require a combination of these approaches

Paneth Cell Alterations During Ischemia-reperfusion, Follow-up, and Graft Rejection After Intestinal Transplantation

BACKGROUND Ischemia-reperfusion (IR) injury is inevitable during intestinal transplantation (ITx) and executes a key role in the evolution towards rejection. Paneth cells (PC) are crucial for epithelial immune defense and highly vulnerable to IR injury. We investigated the effect of ITx on PC after reperfusion (T0), during follow-up, and rejection. Moreover, we investigated whether PC loss was associated with impaired graft homeostasis. METHODS Endoscopic biopsies, collected according to center-protocol and at rejection episodes, were retrospectively included (n=28 ITx, n=119 biopsies) Biopsies were immunohistochemically co-stained for PC (lysozyme) and apoptosis, and PC/crypt and lysozyme intensity were scored. RESULTS We observed a decrease in PC/crypt and lysozyme intensity in the first week after ITx (W1) compared to T0. There was a tendency towards a larger decline in PC/crypt (p=0.08) and lysozyme intensity (p=0.08) in W1 in patients who later developed rejection compared to patients without rejection. Follow-up biopsies showed that the PC number recovered, whereas lysozyme intensity remained reduced. This persisting innate immune defect may contribute to the well-known vulnerability of the intestine to infection. There was no clear evidence that PC were affected throughout rejection. CONCLUSION This study revealed a transient fall in PC numbers in the early post-ITx period, but a permanent reduction in lysozyme intensity following ITx. Further research is needed to determine the potential clinical impact of PC impairment after ITx

Kelvin-Helmholtz instability in the presence of variable viscosity for mudflow resuspension in estuaries

The temporal stability of a parallel shear flow of miscible fluid layers of dif- ferent density and viscosity is investigated through a linear stability analysis and direct numerical simulations. The geometry and rheology of this Newto- nian fluid mixing can be viewed as a simplified model of the behavior of mud- flow at the bottom of estuaries for suspension studies. In this study, focus is on the stability and transition to turbulence of an initially laminar configuration. A parametric analysis is performed by varying the values of three control pa- rameters, namely the viscosity ratio, the Richardson and Reynolds numbers, in the case of initially identical thickness of the velocity, density and viscosity profiles. The range of parameters has been chosen so as to mimic a wide variety of real configurations. This study shows that the Kelvin-Helmholtz instability is controlled by the local Reynolds and Richardson numbers of the inflection point. In addition, at moderate Reynolds number, viscosity strat- ification has a strong influence on the onset of instability, the latter being enhanced at high viscosity ratio, while at high Reynolds number, the influ- ence is less pronounced. In all cases, we show that the thickness of the mixing layer (and thus resuspension) is increased by high viscosity stratification, in particular during the non-linear development of the instability and especially pairing processes. This study suggests that mud viscosity has to be taken into account for resuspension parameterizations because of its impact on the inflec- tion point Reynolds number and the viscosity ratio, which are key parameters for shear instabilities

The uses of coherent structure (Dryden Lecture)

The concept of coherent structure in turbulent flow is a revolutionary idea which is being developed by evolutionary means. The main objective of this review is to list some solid achievements, showing what can be done by using the concept of coherent structure that cannot be done without it. The nature of structure is described in terms of some related concepts, including celerity, topology, and the phenomenon of coalescence and splitting of structure. The main emphasis is on the mixing layer, as the one flow whose structure is well enough understood so that technical applications are now being made in problems of mixing and chemistry. An attempt is made to identify some conceptual and experimental obstacles that stand in the way of progress in other technically important flows, particularly the turbulent boundary layer. A few comments are included about the role of structure in numerical simulations and in current work on manipulation and control of turbulent flow. Some recent developments are cited which suggest that the time is nearly right for corresponding advances to occur in turbulence modeling