Patient-specific electromechanical models of the heart for the prediction of pacing acute effects in CRT: a preliminary clinical validation.

Cardiac resynchronisation therapy (CRT) is an effective treatment for patients with congestive heart failure and a wide QRS complex. However, up to 30% of patients are non-responders to therapy in terms of exercise capacity or left ventricular reverse remodelling. A number of controversies still remain surrounding patient selection, targeted lead implantation and optimisation of this important treatment. The development of biophysical models to predict the response to CRT represents a potential strategy to address these issues. In this article, we present how the personalisation of an electromechanical model of the myocardium can predict the acute haemodynamic changes associated with CRT. In order to introduce such an approach as a clinical application, we needed to design models that can be individualised from images and electrophysiological mapping of the left ventricle. In this paper the personalisation of the anatomy, the electrophysiology, the kinematics and the mechanics are described. The acute effects of pacing on pressure development were predicted with the in silico model for several pacing conditions on two patients, achieving good agreement with invasive haemodynamic measurements: the mean error on dP/dt(max) is 47.5±35mmHgs(-1), less than 5% error. These promising results demonstrate the potential of physiological models personalised from images and electrophysiology signals to improve patient selection and plan CRT.

Influence of glial cells in the dopamine releasing effect resulting from the stimulation of striatal delta-opioid receptors.

Recent data indicate that striatal dopamine release induced by stimulation of delta-opioid receptors is a consequence of glutamate release. However, glial cells, which mainly support glutamate uptake and are involved in glutamate signaling and potentially express delta-opioid receptors, could participate to this effect. The present study investigates the contribution of glial cells in the releasing effects of [d-Pen2, d-Pen5]-enkephalin (DPDPE) by using the gliotoxin l-alpha-aminoadipate (l-alpha AA). Initially, we evaluated the early influence of l-alpha AA local infusion (10 microg/microL) on dialysate levels of glutamate and dopamine under basal or DPDPE treatment conditions. l-alpha AA produced a significant increase of glutamate and dopamine in dialysates (+76% and +50% respectively) and the concomitant infusion of DPDPE (10 microM) significantly enhanced this effect in an additive manner (+110% and +44% respectively). Secondly, we assessed the DPDPE effects on striatal glutamate and dopamine dialysate levels, 2 days after an intra-striatal injection of l-alpha AA which produced destruction of glial cells. This lesion, decreasing the basal glutamate dialysate level as well as its tissue content (by 55% and 36% respectively), prevented the increase in glutamate and dopamine extracellular levels induced by DPDPE. This result confirmed that the DPDPE-induced dopamine release requires an initial glutamate release. However, this effect could reflect a major disruption of glutamatergic transmission caused by the toxin, as suggested by the local infusion of glutamine (2.5 mM) which, in lesioned rats, prevented the decrease in the basal extracellular content of glutamate and restored the DPDPE-induced increase in glutamate and dopamine dialysate levels. Therefore, these results indicate that, although glial cells are essential to maintain functional glutamatergic neurotransmission, they are not directly involved in the process by which stimulation of striatal delta-opioid receptors induces extracellular glutamate release and, consecutively, dopamine release.

[Traissac voice prosthesis. Apropos of 9 years experiences]. / L'implant phonatoire de Traissac. A propos d'une expérience de 9 ans.

BACKGROUND: Long term results are discussed. PATIENTS: A retrospective study of 9 years (1/01/89, 1/01/98) concern 107 laryngectomized patients with 9 patients a part from this period, and 30% without prosthesis. Among 80 patients with prosthesis, 57% had received primary TEPs (tracheoesophageal puncture), 21% delayed primary TEPs and 22% secondary TEPs. Oesophageal voice is always learned with tracheoesophageal voice. RESULTS: We find a success rate (1 month) in 75% of cases, with a maximum follow up time of 8 years (the average is 3 years 1 month). We find a success rate with a long-term result in 66% of cases. Prosthesis removal exists in 30% of cases and oesophageal voice is successfull once out of 3 in this cases. Mean lifetime Traissac's prosthesis is 18 months. After removal, non closed fistulas can exist in 40% of cases, and surgery is always successful. DISCUSSION: Material Traissac's prosthesis explains extended lifetime. CONCLUSION: Traissac's prosthesis gave us satisfaction during a use of 8 years.

Computed tomography in traumatology with special regard to the advances of three-dimensional display.

There is a variety of methods to aid in the diagnosis of fractures requiring operative treatment. A computer program that produces pseudo-three-dimensional (3D) images from sets of axial computed tomograms is used for examining fractures in areas of complex skeletal anatomy. The resulting reconstructions, representing the surface in a form similar to that of anatomic preparations, can facilitate the process of diagnosis. They are also valuable for planning operations. The 3D information can be used to define the size, shape, and location of the various fracture types. We have used the technique in more than 500 patients with injuries to the skull, spine, acetabulum, sternoclavicular joint, shoulder, knee, and calcaneus and are able to demonstrate the benefit of special investigation protocols.

[Bony bridges of the lumbar transverse processes]. / Knöcherne Spangen der Lendenwirbelquerfortsätze.

A traumatic osseous bridge between lumbar transverse processes is a bone formation occurring after severe or even mild trauma of the back. However, only few of the patients with a contusion of the back or a fracture of a lumbar transverse process develop such an osseous bridge. The localisation of the haematoma plays an important role in this process, but myositis ossificans is a mandatory condition. Anamnesis will not lead to traumatic aetiology in all cases, because sometimes the patient is not aware of the fact that a transverse process has been fractured. The diagnosis finally depends on the recognition of the different shapes. The traumatic osseous bridge is characterised by the kind of trauma that causes the fracture of the transverse process. The shapes can be classified as "h", "H", "K", or "Z". Among 72 patients with inter-transverse osseous bridges, only 11 patients have congenital bridges. The congenital osseous bridge shows typical features that can be explained by means of embryogenic and functional dynamic considerations. These symptoms are the O-shape, concavity of the lumbar spine of a pathological nature and the absence of degenerative changes in the corresponding intervertebral space.

[Specific detection of various stages of Osler's disease of the brain using high field magnetic resonance tomography (1.5 Tesla)]. / Spezifischer Nachweis verschiedener Stadien einer Oslerschen Erkrankung des Gehirns mittels Hochfeld MRT (1.5 Tesla).

MR is a sensitive noninvasive examination method for diagnosing parenchymatous cryptic arteriovenous malformations and sequels of cerebral haemorrhage. In a patient with recurring nosebleed and brain stem syndrome eleven so-called cryptic arteriovenous malformations or their haemorrhage sequels were diagnosed via magnetic resonance tomography. Basing on these specific findings, nosebleeding, and a positive family anamnesis, the findings could be classified as belonging to manifestations of Osler's disease (hereditary haemorrhagic telangiectasia). This rare disease is characterised by a triad of signs: telangiectasias, recurring bleeding, and heredity. In this article the specific MR image is compared with the CT pattern and the results are discussed against the background of literature on Osler's disease which is also known as Rendu-Osler-Weber disease.

Absence of complement activation in vitro by sodium meglumine ioxitalamate.

The effect of radiographic contrast media on proteins of the complement system in vitro was investigated using protein level measurement and crossed immunoelectrophoresis. Despite the 20% loss of total serum hemolytic activity (CH50) induced by sodium meglumine ioxitalamate (0.5 M), no significant changes in C3c, C3N or B were detected by radial immunodiffusion. These contrast media did not cause electrophoretic conversion of C3, as assessed by the absence of split product, and the small degree of spontaneous C3 conversion (loss of 20% C3N antigen and the presence of two peaks with C3c antigen) which occurred when serum was incubated in polypropylene tubes, was inhibited by the contrast media. The effects of sodium meglumine ioxitalamate and zymosan in vitro on complement activation were compared.