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Biomedical subjects

M Merle

Publications and source records attributed to M Merle.

251 records · Page 14Linked to original sources
PubMedDate not supplied

Magnetization transfer fast imaging of implanted glioma in the rat brain at 4.7 T: interpretation using a binary spin-bath model.

C6 glioma cells were implanted in the left caudate nucleus of the rat brain. Histologic studies confirmed the presence of neoplastic tissue surrounded by a thin edematous region. Proton magnetization transfer contrast (MTC) fast imaging, using continuous wave off-resonance irradiation, was performed in vivo at 4.7 T with the rapid acquisition with relaxation enhancement (RARE) sequence. The observed MTC allowed very clear distinction of the tumoral region, in which magnetization transfer (MT) ratios were lower than in healthy tissues. Contrasts were analyzed as a function of the offset frequency and the amplitude of the radiofrequency (RF) irradiation. The contrast was higher between the contralateral basal ganglia and the tumor and lower between the tumor and the temporal lobe. Modeling of MT in the three brain regions was performed using a system including free water and a pool of protons with restricted motions. The rate of exchange between the two pools exhibited a decreasing hierarchy from the basal ganglia to the tumor. T2B values for the immobile protons ranged from 9.3 microsec in the basal ganglia to 7.5 microsec for the glioma. The acquisition conditions leading to the highest contrasts between the tumor and the healthy tissues correspond to 3,000 Hz offset frequency and 300 to 700 Hz RF irradiation amplitude.

Animals↗
PubMedDate not supplied

Direct and reverse dorsal metacarpal flaps.

We reviewed the anatomy of vascular systems used for both direct and reverse dorsal metacarpal flaps. The three-dimensional arrangement of the dorsal arterial network of the hand was examined. The collateral and terminal branches of this dorsal arterial network are described as a potential source of blood supply for composite flaps. Three types of dorsal-palmar anastomotic network were identified at the first and second metacarpal spaces, in the web space area. They could provide blood supply to reverse metacarpal flaps. Results of a series of 12 cases of reverse metacarpal flaps are given.

Adolescent↗
PubMedDate not supplied

Comparative 31P and 1H NMR studies on rat astrocytes and C6 glioma cells in culture.

Rat astroglial cells in primary culture (95% enrichment) and C6 glioma cells were adapted to grow on microcarrier beads. In vivo 31P NMR spectra were collected from cell-covered beads perfused in the NMR tube. The NMR-visible phosphorylated metabolite contents of both cell types were determined using saturation factors calculated from the values of longitudinal relaxation times determined for C6 cells using progressive saturation experiments. On the other hand, the amounts of phosphorylated metabolites in cells were determined from proton decoupled 31P NMR spectra of cell perchloric acid extracts. The results indicate that the NTP and Pi contents of the normal and tumoral cells were similar, whereas the PCr level was higher in C6 cells and the NDP and phosphomonoester levels higher in astrocytes. The comparison of 1H NMR spectra of cell perchloric acid extracts evidenced larger inositol and alanine contents in C6 cells, whereas larger taurine and choline (and choline derivatives) contents were found in astrocytes. The Glu/Gln ratio was very different, 3.5 and 1 in C6 cells and astrocytes, respectively. In both cases, the more intense resonance in the 1H NMR spectrum was assigned to glycine. Based on the comparison of the metabolite content of a tumoral and a normal cell of glial origin, this work emphasizes the usefulness of a multinuclear NMR study in characterizing intrinsic differences between normal and tumoral cells.

Animals↗
PubMedDate not supplied

[Value of corticosteroids in bacterial meningitis].

Bacterial meningitis mortality largely results from the intense host inflammation response to infection. Lysis of bacteria releases bacterial components that stimulate production of cytokines. Cerebrospinal fluid concentrations of these cytokines have been shown to correlate with the severity of the meningitis in both experimental and clinical situations. Dexamethasone has an antiinflammatory effect superior to methylprednisolone. It is the only agent with which significant clinical studies have yet been performed. A recent study recommends the routine use of dexamethasone with Haemophilus influenzae meningitis. The immediate and long-term clinical profiles indicate significantly better outcomes for the dexamethasone group. It is prudent to administer dexamethasone before the first parenteral dose of antibiotic to prevent the release of bacterial components induced by bacterial lysis. The search for agents that down modulate inflammation more strongly continues. Some monoclonal antibodies are superior to dexamethasone in experimental meningitis without modification of antibiotic pharmacokinetics.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Toe transfers in traumatic mutilations of the hand in children. Solutions, techniques and results].

Severe mutilating injuries of the hand are rarely encountered in children. Among the reconstruction techniques, partial and total toe transfers are to be considered because these techniques fulfill the growth requirements and because good sensory results can be expected in children. A clinical series of partial or total toe transfers, performed for correction of post traumatic mutilations is presented. Clinical results and technical refinements are discussed.

Adolescent↗
PubMedDate not supplied

[Medical and surgical management of septic diabetic foot].

Infected wounds in diabetic patients are still frequent and the main cause of amputations. The experience of 180 patients admitted for foot lesions between june 1988 and september 1993 shows us the importance of combined medical and chirurgical cares. Non invasive vascular evaluation is reliable and often sufficient for preoperative vascular assessment. Total excision of infected and necrotic tissues is essential for the control of septic conditions. Conservative surgery can be considered a possibility as atypic amputations and adapted footwear may allow quick recovery and early walking. Resigned attitudes and pejorative outlooks are out-of-date, when faced with a diabetic foot problem. Optimal metabolic control and full preoperative assessment guide surgical possibilities.

Abscess↗