Biomedical subjects

Jean Luc Moretti

Publications and source records attributed to Jean Luc Moretti.

4 recordsLinked to original sources

PubMed2004

Leukoaraiosis and mobility decline: a high resolution magnetic resonance imaging study in older people with mild cognitive impairment.

Patterns of leukoaraiosis were analyzed on both T2-weighted fast fluid-attenuated inversion-recovery and 3D T1-weighted sequences in 23 community-dwelling older subjects with mild cognitive impairment. Mobility assessment had allowed their classification into higher and lower mobility groups (P<0.0001). Lower mobility appeared correlated with frontal subependymal lesions (P=0.0005). The absence of marked ventriculomegaly, any thick caps, deep white matter lesions curved along the ventricles bodies, large deep white matter lesions, deep grey matter leukoaraiosis was an hallmark of the higher mobility group (P<0.0001). High resolution MRI demonstrated regular patterns of the subependymal lesions and detected perivascular distribution in other forms of leukoaraiosis. It suggests that the underlying mechanism of mobility decline in the elderly may be impairment of cerebrospinal fluid dynamics with cerebral small vessel disease.

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PubMed2002

Clinical validation of simultaneous dual-isotope myocardial scintigraphy.

Simultaneous dual-isotope (rest thallium-201/stress technetium-99m sestamibi) myocardial single-photon emission tomography (SPET) would be an ideal procedure; however, (99m)Tc cross-talk on the (201)Tl window hampers its routine use. Photon energy recovery (PER) is a spectral deconvolution technique validated for scatter and cross-talk removal in phantom studies and a limited series of patients. In this study we aimed to validate the technique in 295 patients within a context of clinical routine practice. Conventional separate rest (201)Tl myocardial SPET data sets were visually compared with simultaneous dual-isotope data sets corrected by PER. Conventional separate rest (201)Tl data sets were identical to dual PER-corrected (201)Tl data sets in 173 (58.6%) patients. As dual PER (201)Tl data sets are corrected for (99m)Tc cross-talk but also for (201)Tl scatter, they were compared with separate rest (201)Tl data sets corrected by PER in the 122 discordant patients. No difference was found in 77 (26.1%) patients. In 26 (8.8%) patients, the difference consisted in the presence of a defect on dual PER (201)Tl data sets only, mirroring an ischaemic defect on (99m)Tc-sestamibi data sets. This difference can be attributed to the influence of stress on the kinetics of (201)Tl injected at rest. In the remaining 19 (6.4%) patients, the difference between separate and simultaneous PER-corrected data sets was scored as mild in 11 and moderate in eight patients and seemed to be related to multiple methodological factors. It is concluded that PER correctly removes (99m)Tc cross-talk. With the addition of an appropriate attenuation correction, the PER technique may allow the routine use of simultaneous dual-isotope myocardial scintigraphy in the near future.

Artifacts↗

PubMed1991

Central pain and thalamic hyperactivity: a single photon emission computerized tomographic study.

Five patients with central post-stroke pain (CPSP) accepted to be studied according to the following paradigm: a single photon emission computerized tomography (SPECT) using [123I]N-isopropyl-iodoamphetamine (IMP) was made in each patient 20 min following i.v. injection of IMP; during this time, the patients were stimulated in order to reproduce their spontaneous pain. Of the five patients, two had CPSP with hyperpathia following a stroke (with a lesion on CT scan involving the thalamo-cortical pathway in one and involving the thalamus in the other); two had CPSP following a stroke in the middle cerebral artery area, without hyperpathia; and the last patient suffered pain from algodystrophia following a fracture of the wrist. In the two cases with hyperpathia, SPECT demonstrated a contralateral relative hyperactivity in a central region corresponding to the thalamic area. This was not observed in the three other patients. In the two patients with hyperpathia, a second SPECT scan with stimulation of the contralateral pain-free arm did not demonstrate any hyperactivity in the thalamic area. These results suggest that a thalamic neuronal hyperactivity may characterize some hyperpathic syndromes and, in accordance with our previous results obtained in the rat, that the loss of inhibition on medial thalamic neurons may be a main feature of hyperpathia following certain cerebral stroke syndromes.

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PubMedDate not supplied

MRP1 modulation by PAK-104P: detection with technetium-99m-MIBI in cultured lung tumor cells.

BACKGROUND: Resistance mediated by the MultiDrug Resistance protein (P-glycoprotein and MRP1), results in energy-dependent efflux of drugs and 99mTc-MIBI from the cells. The goal of our investigation was to evaluate the capacity of PAK-104P to lower multidrug resistance by decreasing substrate efflux. MATERIALS AND METHODS: 99mTc-MIBI accumulation was quantified in the leukaemia cell line which expresses the P-glycoprotein (K562/R) or not (K562/S) and the small lung cancer cell line which expresses MRP1 (GLC4/R) or not (GLC4/S). Three experimental protocols were used: 1). cells were treated with increasing concentrations of PAK-104P; 2). the plasma membrane potential was lowered; 3). intracellular reduced glutathione (GSH) was depleted. RESULTS: Exposure of cells to 5 microM PAK-104P affected 99mTc-MIBI accumulation as follow: 1). no effect on K562 cell lines; 2). increased 8-fold in GLC4/R; 3). enhanced in GLC4 after GSH concentration and transmembrane potential reduction. CONCLUSION: Assessed by 99mTc-MIBI, PAK-104P modulated MRP1 activity by the decrease of intracellular GSH concentration.

ATP Binding Cassette Transporter, Subfamily B, Mem↗