Recent data on the mechanism of action of theophylline

Since Sutherland's work simply based on the inhibition of phosphodiesterase was questioned, other researches have been carried out, indicating that many mechanisms located in the nervous system, the smooth muscle, and the immunity system interfere. The participation of receptors to adenosine, intracellular calcium ions, regulating calciproteins and autacoids such as prostaglandins was the purpose of numerous experimental researches that allow today to fill up the gap left by the fact that the inhibitor of phosphodiesterase was questioned. However, there are not sufficient but there are many seducing research and hypotheses.     

Horizontal optokinetic responses under stroboscopic illumination in cat,monkey and man

Summary The horizontal optokinetic reflex (OKN) was studied in cat, monkey and man under conditions of steady or stroboscopic illumination. In all species, there was an abrupt decrease in OKN gain for a given spatial displacement of the stimulus between two consecutive stroboscopic flashes. The upper limit of spatial displacement which preserved optimal OKN gain was independent of stimulus velocity and flash frequency. The value of this limit differed in the three species studied. In the cat, OKN gain was affected when the spatial displacement between two stimuli exceeded 0.55° of visual angle. In monkey and man, these limits were 1.48° and 2.87°, respectively. When human subjects were asked to voluntary track the stimulus, the limit value reached 4.3°. This result is discussed in the context of the evolution of the smooth pursuit system and its contribution to optokinetic response.     

High frequency jet-ventilation in esophagotracheal fistula

High-frequency jet-ventilation (HFJV) is not widely used, mainly because of technical problems and difficulty to assess its efficiency. However, there is general agreement on following major indication: artificial ventilation in patients with oesotracheal fistula. In the case reported here, HFJV allowed efficient ventilatory support through an endotracheal tube with deflated cuff. Weaning was progressively obtained. Surgery and postoperative course were uneventful.     

Quantification of multicontrast vascular MR images with NLSnake,an active contour model: In vitro validation and in vivo evaluation

Vessel‐wall measurements from multicontrast MRI provide information on plaque structure and evolution. This requires the extraction of numerous contours. In this work a contour‐extraction method is proposed that uses an active contour model (NLSnake) adapted for a wide range of MR vascular images. This new method employs length normalization for the purpose of deformation computation and offers the advantages of simplified parameter tuning, fast convergence, and minimal user interaction. The model can be initialized far from the boundaries of the region to be segmented, even by only one pixel. The accuracy and reproducibility of NLSnake endoluminal contours were assessed on vascular phantom MR angiography (MRA) and high‐resolution in vitro MR images of rabbit aorta. An in vivo evaluation was performed on rabbit and clinical data for both internal and external vessel‐wall contours. In phantoms with 95% stenoses, NLSnake measured 94.3% ± 3.8%, and the accuracy was even better for milder stenoses. In the images of rabbit aorta, variability between NLSnake and experts was less than interobserver variability, while the maximum intravariability of NLSnake was equal to 1.25%. In conclusion, the NLSnake technique successfully quantified the vessel lumen in multicontrast MR images using constant parameters. Magn Reson Med 51:370–379, 2004. © 2004 Wiley‐Liss, Inc.     

Computer-assisted analysis of three-dimensional MR angiograms.

The software tools required for postprocessing of magnetic resonance (MR) angiograms include the following functions: data handling, image visualization, and vascular analysis. A custom postprocessing software called Magnetic Resonance Angiography Computer Assisted Analysis (MARACAS) has been developed. This software combines the most commonly used three-dimensional visualization techniques with image processing methods for analysis of vascular morphology on MR angiograms. The main contributions of MARACAS are (a) implementation of a fast method for stenosis quantification on three-dimensional MR angiograms, which is clinically applicable in a personal computer-based system; and (b) portability to the most widespread platforms. The quantification is performed in three steps: extraction of the vessel centerline, detection of vessel boundaries in planes locally orthogonal to the centerline, and calculation of stenosis parameters on the basis of the resulting contours. Qualitative results from application of the method to data from patients showed that the vessel centerline correctly tracked the vessel path and that contours were correctly estimated. Quantitative results obtained from images of phantoms showed that the computation of stenosis severity was accurate.     

Neuroanatomical Correlates of Visually Evoked Sexual Arousal in Human Males

Brain areas activated in human male sexualbehavior have not been characterized precisely. For thefirst time, positron emission tomography (PET) was usedto identify the brain areas activated in healthy males experiencing visually evoked sexualarousal. Eight male subjects underwent six measurementsof regional brain activity following the administrationof [¹⁵O]H₂O as they viewedthree categories of film clips: sexually explicit clips,emotionally neutral control clips, and humorous controlclips inducing positive but nonsexual emotions.Statistical Parametric Mapping was used to identifybrain regions demonstrating an increased activity associatedwith the sexual response to the visual stimulus.Visually evoked sexual arousal was characterized by athreefold pattern of activation: the bilateralactivation of the inferior temporal cortex, a visualassociation area; the activation of the right insula andright inferior frontal cortex, which are two paralimbicareas relating highly processed sensory information with motivational states; and the activation ofthe left anterior cingulate cortex, another paralimbicarea known to control autonomic and neuroendocrinefunctions. Activation of some of these areas was positively correlated with plasma testosteronelevels. Although this study should be consideredpreliminary, it identified brain regions whoseactivation was correlated with visually evoked sexualarousal in males.     

Hypoxic Single-Pass Isolated Hepatic Perfusion of Hypotonic Cisplatin: Safety Study in the Pig

Background  

Isolated hepatic perfusion (IHP) of chemotherapy has been proposed to deliver high doses of drug while avoiding systemic toxicity. Hypotonic cisplatin has a high in vitro activity on human colon cancer cells. We studied the safety of a 30-min hypoxic single-pass IHP with hypotonic cisplatin.