Search PubMed⌕ Search

Biomedical subjects

G Marchal

Publications and source records attributed to G Marchal.

At least 487 records · Page 27Linked to original sources
PubMedDate not supplied

Functional recovery of subepicardial myocardial tissue in transmural myocardial infarction after successful reperfusion: an important contribution to the improvement of regional and global left ventricular function.

BACKGROUND: The transmural extent of myocardial necrosis after an acute coronary artery occlusion can vary considerably. The contribution of residual subepicardial viable myocardium to global left ventricular function is largely unknown. METHODS AND RESULTS: We studied 12 patients with single-vessel disease 1 week after successful reperfusion of a first transmural anterior myocardial infarction (MI). With PET, myocardial blood flow (MBF) and glucose metabolism were measured regionally, and the viability was graded as normal, mismatch, or match with severely (<50% of normal) or intermediately (50% to 80% of normal) impaired MBF. Magnetic resonance tagging was used to regionally quantify fiber strains, wall thickening, and ejection fraction in patients 1 week and 3 months after the MI and in age-matched healthy volunteers. From 1 week to 3 months, subepicardial fiber shortening improved significantly in the match region (MBF <50%, -5.1+/-7.0% to -9.9+/-8. 7%; MBF of 50% to 80%, -7.1+/-7.6% to -14.9+/-7.9%). This was associated with an improvement in regional ejection fraction in the infarcted myocardium (29.6+/-21.8% to 43.5+/-15.5%, P<0.0001) and in normal regions (54.3+/-15.1% to 56.5+/-13.1%, P=0.013), contributing to an increase in global ejection fraction from 44.2+/-22.2% to 49. 3+/-17.9% (P<0.0001). CONCLUSIONS: Functional recovery of viable subepicardial regions is a mechanism of late improvement in regional and global ejection fraction after a so-called transmural MI.

Aged↗
PubMedDate not supplied

Multimedia E-mail systems for computer-assisted radiological communication.

In the film-based organization of communicating radiological results to the referring physician, the different media (text, images, graphics, voice) are separated. When using computer technology, multimedia reports containing links between these different media can be used. This changes the way radiological reports are generated, accessed, and possibly discussed. We performed experiments in a clinical setting using two different metaphors for communicating multimedia information. In the 'paper metaphor', labels in the report text are linked to annotations in selected images. In the 'slide presentation metaphor', annotated images are presented synchronously to a spoken report. With both systems additional interaction between radiologist and referring physician is supported using multimedia 'electronic mail'. The experiments indicate that multimedia does not only significantly increase the efficiency of information transfer, but also has the potential to make reporting itself more efficient. Given that the amount of image-related information keeps growing, multimedia links are a promising method to give efficient access to the most relevant information.

Computer Graphics↗
PubMedDate not supplied

Design for user efficiency in a dedicated ICU viewing station.

The intensive care unit (ICU) is one application where significant benefit is expected from the use of digital technology in the acquisition, management and presentation of images. However, the potential benefits should not be outweighed by disadvantages of current digital technology. One of the bottlenecks is the efficiency of image viewing using a workstation, especially if this viewing station is implemented using affordable commonly available hardware. In this paper we describe the design concepts of a relatively low-cost but efficient viewing station for chest images, and discuss clinical experience with this system at an ICU ward. The user interface has been optimized towards the specific patterns of ICU image viewing. By anticipating user requests and preparing images during idle times of the computer, the mean image access time could be reduced by a factor of 4, while most images could be presented instantaneously. Information from the hospital information system (HIS) is exploited in the user interface, and a simplified PAC-HIS coupling has been implemented for the simultaneous presentation of images and reports.

Belgium↗
PubMedDate not supplied

Using WWW and JAVA for image access and interactive viewing in an integrated PACS.

We start from the observations that (1) potential benefits from PACS can only be realized if PACS and HIS are integrated into a 'multimedia medical information system', and (2) that this also requires integration at the level of the user interface. The user interface should allow integrated interaction with information from different subsystems, of which PACS is one. However, in the real world, different information systems are constructed using different technologies. Moreover, radiological image viewing is a highly interactive task that puts a particular burden on the graphical user interface. We describe our experiences in applying technology emerging around the 'World Wide Web' (WWW) for interactive access to an integrated PACS/HIS. We illustrate the use of Web browsers to access new medical services, touch technologies for interactive access to HIS-PACS information, and emphasize the potential of JAVA applets. We argue that JAVA may become an important tool for providing highly interactive user interfaces to larger multimedia information systems. We discuss Web technology in the general context of HIS/PACS integration.

Archives↗
PubMedDate not supplied

[Increased catabolism of antigen and enhanced recruitment of antigen-sensitive cells by activation of macrophages with a bacterial phospholipid extract (EBP) (author's transl)].

Intravenous (IV) infection of a bacterial phospholipid extract (EBP) 24 H before IV immunization of mice with sheep red blood cells has modified the specific immune response. A decrease of the response evaluated by the number of rosette-forming cells was observed after the larger doses of EBP. This effect appeared secondarily to an increased catabolism of antigen. Infection of a medium sized dose of EBP directly into the portal vein induced a decreased response by enhancing antigen phogocytosis by liver macrophages. The same amount of EBP injected IV into a systemic vein increased the immune response. An enhanced phagocytosis by macrophages which do not act in the immune response appeared likely after the larger stimulation. Irradiated spleen cells when transferred into naive recipients showed a decreased immunogenicity when obtained from mice injected with antigen and previously treated by the larger doses of EBP. On the other hand, after treatment of mice with low of medium sized doses of EBP, the immune response was increased. Twice the number of rosette-forming cells was observed in treated mice on days 3, 4 and 5 after immunization. The number of B rosette-forming cells appeared higher than the T rosettes following this treatment. This effect appeared secondarily to an increased recruitment of precursor cells. Transfer into naive irradiated recipients of treated spleen cells mixed with antigen was without effect. On the contrary, an enhanced number of rosette-forming cells was detected after transfer of normal spleen cells into irradiated and EBP-treated recipients. This enhancement of response appeared to be produced by more efficient recruitment of precursor cells as demonstrated by an increased frequency of antibody-forming cells in an in vivo limiting dilution technique.

Animals↗
PubMedDate not supplied

[A micromethod for measuring macrophage chemotactic factor(s) in the supernatants of mouse lymphocyte cultures stimulated by concanavalin A].

A micromethod is described for the measurement of the macrophage chemotactic factor (s) released by activated murine lymphocytes in culture. Lymphocytes are stimulated by various doses of concanavalin A in the wells of a tissure culture microplate. Two wells are used for thymidine incorporation measurement and three wells for the chemotactic assay. For this assay, microchambers are prepared from segments of a disposable tuberculine syringe closed on oneend by gluing a small Millipore filter. These chambers are placed in the wells of the tissue culture plate so that the filter is just in contact with the supernatant of the lymphocyte culture. They are then filled with 5.104 macrophages obtained from the peritoneum of normal mice suspended in 100 mul of medium 199 supplemented with bovine serum albumin. The macrophages migrate into the filter more deeply in experiments with stimulate lymphocytes than in experiments with non-stimulated cultures. The distance travelled by the macrophage is measured by the difference between the microscope focal adjustments for the top of the filter and the deepest migrating cells respectively.

Animals↗
PubMedDate not supplied

Prominent dural enhancement adjacent to nonmeningiomatous malignant lesions on contrast-enhanced MR images.

Prominent dural enhancement was noted in 10 (16%) of 61 superficial malignant intracranial tumors studied with contrast-enhanced MR imaging during a 2-year period. Included were six glioblastomas, three parenchymal metastases, and one case of dural metastasis. Seven patients had surgery. In four, there was extensive leptomeningeal invasion in the center of the lesion. In two of these lesions there was firm attachment of the center of the tumor to the dura, but without dural invasion despite extensive external carotid artery supply to the tumor in one case. In two cases the overlying dura was normal, and there was no leptomeningeal tumoral invasion. In the case of dural metastasis, huge nodular lesions were present along the inner aspect of the dura. In none of the cases did prominent dural enhancement adjacent to the tumor correspond with tumoral invasion or extension to the dura. Prominent dural enhancement on contrast-enhanced MR images appears to be much less frequent in malignant tumor than in meningioma, where it is seen in up to 60% of the cases. We believe this finding is more likely to represent reactive changes of the dura than tumoral invasion.

Brain Neoplasms↗
PubMedDate not supplied

Intracranial meningiomas: correlation between MR imaging and histology in fifty patients.

The magnetic resonance (MR) findings in 50 surgically verified intracranial meningiomas were reviewed. An attempt was made to correlate their signal intensity on spin echo (SE) T1-weighted, proton density [N(H)], and T2-weighted images with the different histologic subtypes. The T1-weighted images were nonspecific in differentiating the subtypes of meningiomas. On proton density and T2-weighted images, more information was available, but there remained large group (46%) of meningiomas that were not classifiable. The average signal intensity scores on T1-weighted, proton density, and T2-weighted images in the different histologic subtypes were correlated with each other using the Student t test. Only one significant correlation (psammomatous-anaplastic) and three almost significant correlations (syncytial-transitional or psammomatous and transitional-psammomatous) were found. Different histologic subtypes may have a different MR appearance, but this does not suffice to reach a histologic diagnosis by MR imaging.

Adult↗
PubMedDate not supplied

[Detection of weak graft-versus-host reactions by the suppressive effect on the immune response (author's transl)].

Weak graft-versus-host reactions induced between H-2 compatible strains are not detected by the splenomegaly assay in newborn mice. Similarly the proliferative response in the mixed lymphocyte culture or the popliteal lymph node assay was not extensive in some combinations. On the contrary, the inhibition of the specific immune response to heterologous red cells was observed when graft occurred from 15 days before immunization. So the weak graft-versus-host reactions appeared to be easily detected by the suppressive effect on antibody synthesis.

Animals↗
PubMedDate not supplied

The superior mesenteric artery syndrome: an unusual complication in a patient with the Hallervorden-Spatz syndrome.

A 12 year old patient with the Hallervorden-Spatz syndrome and suffering from acute intestinal obstruction during treatment with benztropine is presented. An upright film of the abdomen and opacification of the duodenum showed an abrupt cut off just to the right of the third lumbar vertebra. Abdominal ultrasound demonstrated a reduced superior mesenteric-aortic angle and distance. Predisposing factors in this patient were supine position, extreme opisthotonos and duodenal hypotonia induced by benztropine.

Benztropine↗