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Biomedical subjects

C Moisan

Publications and source records attributed to C Moisan.

8 recordsLinked to original sources
PubMed2005

Usefulness of fine needle aspiration cytology in the diagnosis of loco-regional recurrence of differentiated thyroid carcinoma.

AIM: The aim of our study was to define the usefulness of fine needle aspiration cytology (FNAC) in the assessment of loco-regional recurrence of differentiated thyroid carcinoma (DTC). METHODS: Among 1182 consecutive patients treated and followed for DTC from 1992 to 2001, we retrospectively analysed 65 FNAC results of patients presenting a suspicion of loco-regional recurrence. Recurrences were proved at histology in 35 cases and by cervical radioiodine uptake on post-therapeutic WBS (whole body scan) in nine cases. RESULTS: Among the 44 recurrences, FNAC results were malignant, benign and unsatisfactory in 33, two and nine cases, respectively. For the diagnosis of malignancy, FNAC sensitivity was 94%, specificity 100%, positive predictive value 100% and negative predictive value 87%. In the 35 cases where divergent results between diagnostic WBS (37-111MBq (131)I) and Tg level were observed, FNAC assessed the final status in 22 cases (malignant and benign in 17 and five cases, respectively). Of the 12 non-functioning and non-secreting lesions, FNAC diagnosed malignancy in four of the five malignant cases and ruled out malignancy in all seven benign lesions. CONCLUSION: These results outline the interest of FNAC in the assessment of loco-regional recurrences of DTC, especially when classical follow-up tools such as WBS and/or Tg level are unable to detect the recurrences.

Adult↗
PubMed2001

[Insulin sensitivity, blood pressure and cardiovascular diseases].

Essential hypertension is one of the main components of the insulin resistance syndrome. Blood pressure levels are especially critical for the cardiovascular prognosis of patients with diabetes. However, whether the relationship between blood pressure levels and insulin sensitivity is causal, or just an association, remains debatable. In this study, this relationship is explored through the data of currently available clinical trials.

Blood Pressure↗
PubMed2000

Endovascular procedures under near-real-time magnetic resonance imaging guidance: an experimental feasibility study.

PURPOSE: The purpose of this study was to assess the feasibility of insertion of endovascular stents and the precision of an open-field interventional magnetic resonance imaging (iMRI) system in an in vivo model. METHODS: A feasibility study was undertaken at a university-affiliated hospital. Three male piglets with an average age of 6 months and a weight between 70 and 77 kg and two 3-month-old male piglets that weighed 40 to 44 kg were anesthetized. The five piglets underwent placement of nitinol stents inserted through the right femoral artery, under the guidance of a SIGNA-SP 0. 5T open-configuration iMRI unit. With a dedicated high-resolution near-real-time MRI sequence, the stent was guided and deployed onto a predefined target. RESULTS: The main outcome measures were the duration of the procedure from the beginning of positioning to the end of deployment of the stent, the final position of the stent in relation to the target on the iMRI screen, and comparison with autopsy findings. Three stents were deployed within the aorta at the level of the renal arteries, and two were deployed within the right iliac artery just below the aortic trifurcation. The average duration of the endovascular deployment was 13 minutes. There was an agreement of 0.6 mm in the position of the stent as observed on iMR images and found at autopsy. When the piglets were sacrificed, the average distance between the stents and the predefined target was 7. 8 mm, mostly because of the migration of one stent. Axial views allowed for accurate determination of stent impaction on the vascular wall. CONCLUSIONS: This study confirms the feasibility of stent deployment under near-real-time MRI guidance. It also emphasizes some inherent characteristics that hold promise with regard to other conventional techniques: stents and vascular structures are visualized in near-real-time in any desired plane, and the technique is performed without the potential adverse effects of ionizing radiations and iodinated contrast agents.

Animals↗
PubMed2000

In vitro evaluation of the accuracy of open-configuration MRI in endovascular techniques.

The purpose of this study was to determine the accuracy of an interventional magnetic resonance imaging (iMRI) system to position an endovascular catheter in an in vitro model that simulated an infrarenal aortic aneurysm. Adequate visualization of abdominal aortic aneurysms (AAAs) was shown previously in humans. A dedicated near-real-time imaging protocol readily available on a Signa SP 0.5T open configuration MRI unit (General Electric Medical Systems, Milwaukee, WI, USA) was used to image the AAAs of ten human volunteers. A pulsatile in vitro model that simulated an AAA was built, which included the kidneys, the renal arteries, the aorta, and the iliac arteries. A catheter was advanced to a predetermined target through one of the iliac limbs of the model. Using two different techniques, the accuracy with which an interventionist could position the endovascular catheter under the near-real-time guidance of the iMRI system was evaluated. The AAAs of all ten patients were visualized, including the aneurysm wall, the thrombus within it, and the residual lumen, while maintaining adequate contrast, signal, and imaging speed. The position of the catheter was evaluated on target in 42 in vitro procedures. This series of tests showed an average accuracy of 1 mm for catheter positioning. The near-real-time imaging mode of the iMRI system enabled satisfactory evaluation of human AAAs, and it showed great accuracy for catheter positioning in the in vitro model. These results provide optimism regarding the potential of iMRI in endovascular surgery.

Aortic Aneurysm, Abdominal↗
PubMedDate not supplied

Hydrostatic pressure effects on eel mitochondrial functioning and membrane fluidity.

Aerobic metabolism which is required for long swimming activities during the eel's spawning migration at depth, is a potential target for pressure effects due to its components located in the inner mitochondrial membrane (respiratory chain and oxidative phosphorylation). Previous studies have evidenced that eels are able to acclimatize to pressure through membrane fluidity adjustment. However these studies were performed on the premigratory stage (yellow stage), which never encounters high pressure. Metamorphosis (silvering) seems to preadapt eels (at the silver stage) to most of the environmental changes they will encounter during migration. Is it also true for pressure resistance? This study shows that yellow eels exhibit a higher pressure sensitivity than silver eels (compression effects). The acclimatization period (21 days at 10.1 MPa) cancels the differences in pressure sensitivity and in aerobic metabolism observed at 0.1 MPa between the two stages. The mechanisms, which take place in yellow eels during acclimatization to high pressure, appear to be already present in silver eels before pressure exposure. Indeed at 0.1 MPa, silver eels exhibit higher membrane fluidity and proportions of membrane polyunsaturated fatty acids. Metamorphosis, by improving membrane fluidity, seems to allow silver eels to cope with hydrostatic pressure without spending energy in acclimatization processes.

Acclimatization↗
PubMedDate not supplied

Does hydrostatic pressure have an effect on reactive oxygen species in the eel?

Eels are submitted to hydrostatic pressure (HP) during their spawning migration (about 6000 Km). Before migration, they change from the yellow to the silver stage (silvering process). The effects of HP in relation to the silvering process have been studied on aerobic metabolism and more precisely on reactive oxygen species (ROS) metabolism. HP acclimatization of yellow eels improves oxidative phosphorylation together with supposed concomitant changes in electron leak and ROS production. Therefore hydroxyl radical (OH*) production, superoxyde dismutase and catalase activities, malondialdehyde content and in parallel oxygen consumption were measured in the red muscle of long-term pressure exposed and control group yellow and silver eels. At atmospheric pressure, yellow eels exhibited significantly higher oxygen consumption and OH* production than silver eels; and significantly lower malondialdehyde content. This could be due to the increase in membrane fluidity induced by the silvering process. Long-term HP exposure decreases yellow eel oxygen consumption which becomes similar to that of the silver stage. In parallel there is a decrease in OH* production and concomitantly antioxidant enzyme activities follow the same tendency. Thus the respiratory chain improvement in pressure acclimatized yellow eels is accompanied by a ROS production decrease which could mean an electron leak decrease.

Acclimatization↗
PubMedDate not supplied

A comparative study of reactive oxygen species in red muscle: pressure effects.

In ectotherms as well as in endotherms, the mitochondrial respiratory chain is the major source of reactive oxygen species (ROS) including the highly reactive, hydroxyl radical (OH*). It is known that the different steps involved in ROS production and the antioxidant systems are comparable in ectotherms and endotherms. But regulatory mechanisms in ROS production are less known especially in fish submitted to environmental changes. Firstly, we performed a ROS muscle metabolism interspecies study, using trout and eels as ectotherms and rats as endotherms, measuring OH* production, superoxide dismutase and catalase activities and in parallel oxygen consumption (MO2). Secondly, we studied the effects of an environmental factor (hydrostatic pressure) on ROS metabolism in both fish species. The results show that, at atmospheric pressure, fish have a higher OH*/MO2 ratio than rats which exhibit a higher superoxide dismutase activity. In fish exposed to hydrostatic pressure, this ratio is reversed so that for the same MO2 value, fish produce less OH* under hydrostatic pressure than at atmospheric pressure.

Animals↗