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Biomedical subjects

J Meunier

Publications and source records attributed to J Meunier.

At least 19 recordsLinked to original sources
PubMed1995

Echographic image mean gray level changes with tissue dynamics: a system-based model study.

In echography, several groups have reported a systematic decrease in the total backscattering intensity or image mean gray level during myocardial contraction with a minimum at end-systole and maximum at end-diastole. In order to investigate this phenomenon, we use a three-dimensional inhomogeneous continuum model to mimic the tissue as a collection of cells that scatter the acoustic wave due to their individual impedance. The mathematical analysis clearly shows the relationship between the mean gray level changes and the size, orientation, and deformation of the cells that compose the tissue, as well as the frequency of the transducer. Using a myocardial model example, the mean gray level changes reported in the literature during contraction are described in terms of changes in orientation and deformation of cardiac fibers. The model is simple and should set the ground for further study and analysis of speckle pattern changes during tissue motion.

Echocardiography↗
PubMed1987

Expression of HLA-DR and OKT6 antigens on keratinocytes and dendritic cells in pemphigus.

The expression of HLA-DR and OKT6 antigens by epidermal cells in pemphigus was examined by immunohistochemical methods using skin biopsy specimens from human patients with pemphigus vulgaris. Changes in the distribution and subpopulations of Langerhans cells were observed in lesional (involved) skin. HLA-DR-positive, OKT6-negative dendritic cells were numerous and generally confined to the margins of epidermal clefts. OKT6-positive dendritic cells were rare or absent in lesional skin. The HLA-DR-positive, OKT6-negative dendritic cells associated with intraepidermal clefts are most likely functionally active antigen-presenting cells, which may play a role in lesion development. Aberrant expression of HLA-DR molecules by keratinocytes was observed in both involved and uninvolved skin, and may function to facilitate the recognition of surface-bound pemphigus antigen(s) by immunocompetent cells.

Antibodies, Monoclonal↗
PubMed1986

[Efficiency of associative memory inherent in post-tetanic potentiation].

An associative memory is modeled in networks of cells that are assumed to have the short-term plasticity of the neuromuscular junction of the frog. The data relating synaptic transmission efficiency and stimulation frequency for post-tetanic potentiation of the neuromuscular junction are represented by polynomial expansions. Simulation of storage and retrieval demonstrates that functional associative memory is feasible based on this particular synaptic plasticity. Retrieval reaches a maximum efficiency at a delay of three minutes after storage and is lost after about 9 min. The signal to noise ratio of the retrieved pattern drops steadily as additional associations are stored in memory but retrieval appears to be possible with up to four stored associations. Although the data are derived from synapses not normally proposed as a basis for memory functions, the results here will generalize to other synaptic junctions located more centrally that have similar characteristics. This simulation technique allows the efficiency of associative memory based on various types of synaptic plasticity to be evaluated.

Brain↗
PubMed1985

[Postoperative analgesic effect of pethidine injected epidurally].

Postoperative pain was treated by epidural administration of 30 to 50 mg pethidine (5 mg X ml-1) in a group of 36 patients who had undergone retropubic prostatectomy. Surgery was carried out under epidural anaesthesia with lidocaine. Pain was assessed by means of the visual analogue scale. A general study of the effects of injections and reinjections showed that analgesia thus obtained was excellent at the first hour after injection and lasted 3 to 5 h. The effect of the first postoperative injection on spontaneous pain was studied in 14 patients. Statistical analysis (Wilcoxon test) demonstrated that the fall in pain score was significant at the first and third hours after injection, but not significant at the fifth hour. The analgesia to that pain produced by coughing was studied in 11 patients. There was a significant decrease in pain at the first hour after injection; differences in pain scores at the third hour were not significant. No noticeable side-effect was observed. It was concluded that low doses of epidural pethidine were efficient on postoperative pelvic abdominal pain, but that doses should be increased if painless coughing was required.

Aged↗
PubMed1985

Prostaglandin E2 production by EL 4 leukemia cells from C57BL/6 mice: mechanism for tumor dissemination.

Murine EL 4 leukemia cells contained and secreted prostaglandin E2 (PGE2). PGE2 was secreted into the culture media during in vitro growth, as well as into plasma during growth in the peritoneum of inbred C57BL/6 mice. For the study of the role of PGE2 in tumor dissemination, migration of EL 4 cells out of glass capillary tubes was used as an in vitro model for tumor spread in a host. PGE2 enhanced the in vitro migration of EL 4 cells while indomethacin, a prostaglandin synthesis inhibitor, reduced the extent of migration. When EL 4 cells were allowed to migrate into medium containing both indomethacin and PGE2, the cells exhibited an enhanced migration ability suggesting an extrinsic effect on cells by PGE2. The participation of tumor-derived PGE2 in promoting tumor spread in a host was supported by demonstration that EL 4 cells grown in indomethacin-treated mice secreted less PGE2 and had reduced in vivo dissemination ability. These results indicated that tumor spread was promoted by tumor-derived PGE2. The extent of migration and dissemination can be reduced by prostaglandin synthesis inhibitors such as indomethacin.

Animals↗
PubMed1985

Relationships between morphology, dissemination, migration, and prostaglandin E2 secretion by cloned variants of Lewis lung carcinoma.

Lewis lung carcinoma cells (LLC) were isolated and cloned from metastatic lung nodules of C57BL/6 mice or from a cultured parental LLC line. Their dissemination abilities were defined in vivo by their capacities to disseminate to the lungs following s.c. or i.v. injection into mice and in an in vitro model for tumor dissemination by their ability to migrate out of glass capillary tubes. Cloned LLC cells with an enhanced dissemination capacity exhibited a rounded morphology, were nonadherent during in vitro culture, and readily migrated out of capillary tubes. In contrast, clones not capable of dissemination were adherent and spread during in vitro culture and did not migrate out of capillary tubes. Production of prostaglandin E2 by these clones was measured by a radioimmunoassay. An inverse relationship was observed between the extent of migration and dissemination of clones and their ability to secrete prostaglandin E2 in vitro and in vivo. However, the prostaglandin E2 did not regulate the migration-dissemination capacities of LLC clones as inhibiting prostaglandin synthesis did not alter their capacity to migrate in vitro or to lodge in the lungs following i.v. inoculation into mice.

Animals↗
PubMed1985

Clinical study of muzolimine in acute renal failure, pharmacodynamics and pharmacokinetics.

UNLABELLED: The aim of this study was to test the efficiency of muzolimine in patients with acute renal failure (ARF). METHODS: 6 patients, all males, 46 to 78 years old (mean 67.3 +/- 12.5) suffering from acute renal failure as a complication of a surgical procedure (4 cases) or a medical disease (2 cases) were selected. Creatinine clearance rates were below 20 ml/min for all subjects except one (mean: 14.4 ml/min range 4-34), blood urea levels from 21 to 65 mmol/l (mean = 36.4); mean urinary output, during the 24 hours preceding the study (D-1) was 100.4 +/- 57 ml/h (range 36-208) without any diuretic treatment. No patient was on dialysis. On the treatment day a single oral dose of muzolimine (240 mg) was administered in the morning. During the treatment day (D0) and the post treatment day (D + 1), pharmacodynamics and pharmacokinetics were evaluated. Mean urinary output increased from 1.67 +/- 0.95 ml/min, at D-1 to 3.24 +/- 2 ml/min at D0 (NS), with great differences between patients. The main effect was noted between 0 and 6 hours after the ingestion of muzolimine. The mean electrolyte output increased from D0 to D1 for Na+ (0.1 mmol/min +/- 0.08----0.25 +/- 0.1-NS), K+ (0.05 mmol/min +/- 0.02----0.08 +/- 0.07-NS), Cl- (0.07 +/- 0.07 mmol/min----0.30 +/- 0.12 p less than 0.05) and Ca++ (1.89 +/- 1.89 meq/24 h----4.1 +/- 2 NS), with large individual variations. Mean urea output increased slightly in only 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1984

[Effects of a postpituitary extract and lysine vasopressin on portal and systemic hemodynamics in the cirrhotic patient].

The purpose of this work was to study the hemodynamic effects of a pituitary extract (Post-Hypophyse, Choay, EPH) and of lysine vasopressin (Diapid, Sandoz, VP). Cardiac, pulmonary and liver hemodynamics were measured in 50 cirrhotic patients before and during intravenous infusion (0.45 IU/kg/h) of EPH (24 patients) or VP (26 patients). EPH and VP did not have identical consequences in cardiac output and systemic resistances. EPH significantly increased cardiac output and significantly decreased systemic resistances while VP significantly and increased systemic resistances. Both vasoactive drugs similarly decreased myocardial performances. EPH and VP had a moderate influence on WHV/IVC pressure gradient. This was variable from one patient to another. The decrease of WHV/IVC pressure gradient observed during EPH infusion was mainly related to an increase of IVC pressure. Since the effects of both drugs on WHV/IVC pressure gradient are slight and unpredictable and they exert an important effect on cardiopulmonary hemodynamics, caution should be taken in administering EPH or VP to cirrhotic patients. The clinical use of EPH or VP should be undertaken only when cardiac and liver hemodynamics monitoring are available.

Cardiac Output↗
PubMed1982

[Recurrent paroxysmal myoglobinuria with acute renal insufficiency caused by muscular carnitine (palmitoyltransferase deficiency. A case].

A 45-year-old man was hospitalized on 3 occasions for recurrent myalgias with paroxysmal myoglobinuria resulting in two episodes of acute renal failure. The second episode was fatal: the patient died of shock and hyperkaliaemia during haemodialysis. The predominant signs and symptoms were muscle pain with functional deficit, signs of renal failure and a rise in serum enzymes. All examinations were negative between attacks. Muscle biopsies showed a major degree of myolysis, and biochemical tests demonstrated severe muscle palmityl transferase deficiency associated with partial deficiency of muscle carnitine. The diagnostic features and physiopathology of the disease are reviewed.

Acute Kidney Injury↗
PubMed1982

[Evaluation of nutritional status in hospital surgical patients (author's transl)].

The nutritional status of 90 hospital surgical patients was evaluated on admission by simple, easily measured anthropometric and biological indexes. The results indicated that many patients were admitted with malnutrition, the degree of which varied according to the indices utilized. Anthropometric measurements showed that 29 to 35% of the patients had moderate malnutrition and 0 to 18% severe malnutrition, while biological indexes revealed moderate or severe malnutrition in over 50% of the subjects. Changes in indices were assessed in 51 patients during their stay in hospital. There was a significant decrease in all anthropometric indexes (p less than 0.01) and in blood albumin (p less than 1.10(-6)) though not in other biological indexes. Differences in sensitivity between indexes may be due to the fact that they reflect activities in different tissues. Several indexes must therefore be utilized in hospital patients to make detection and monitoring of malnutrition more reliable and to evaluate its various aspects.

Adult↗
PubMed1978

[Bronchofibroscopy. 6 questions, 6 fundamental answers].

The authors report the aims, methods, techniques of sampling and the tolerance of broncho-fibroscopy, correlating literature and their personal experience of a thousand examinations. They consider it a very simple examination which without any inconvenience can be used in very serious cases as well as for out-patients. They insist on the technique of biopsy and directed aspiration and demonstrate that with experience the yield of the method can be improved. They conclude by saying that a histo-cytological diagnosis can be made in 95% of cases of bronchial cancers. In their experience, tolerance to this examination is always very good.

Biopsy↗