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Biomedical subjects

M Moreau

Publications and source records attributed to M Moreau.

At least 163 records · Page 9Linked to original sources
PubMed1985

Polymeric dyes: useful nonabsorbable reference markers for intestinal perfusion studies in animals.

The properties of two polymeric dyes were examined to determine their suitability as nonabsorbable reference markers for intestinal perfusion studies. The first dye was a violet anthroquinone dye, R-478, named polyporphyre; the second was a blue anthroquinone dye, R-411, named polycyanine. The dyes could be determined spectrophotometrically over a concentration range of 0.03-5 microM (1-200 micrograms/mL) and had no appreciable osmotic effect. They were light stable and their absorption spectra did not change in solution over a pH range of 1-11. The dyes had a molecular weight of approximately 40,000 by gel permeation chromatography; they did not appear to have hydrophobic binding sites because they did not bind added dihydroxy bile acid or fatty acid anions. Determination of the dyes was not influenced by the presence of bilirubin when the latter was present at concentrations reported to occur in small intestinal content during digestion. The dyes did not interfere with an endpoint enzymatic determination of bile acids. The dyes caused little quenching of 3H- or 14C-radioactivity in a toluene-based liquid scintillation cocktail. Dyes were easily removed from aqueous solution by passage over a large-pore anion exchange column or by a BaCl2:ZnSO4 protein precipitation procedure. When tested in a rat jejunal perfusion model, changes in dye concentration evoked by hypotonic or hypertonic perfusates were identical to those of polyethylene glycol 4000, a commonly used reference marker. The dyes did not influence the rate of glucose absorption and did not bind to mucus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Application of the trauma score in the prehospital setting.

The Trauma Score (TS) is a physiologic measure of injury severity that correlates with patient outcome. Application of the TS has shown that it is useful for patient triage, for predicting patient outcome, and as a means of normalizing for case mix when comparing prehospital care and transport modalities. Our study explored the interrater reliability of assessments of TS variables that were made by emergency medical technicians and paramedics during the prehospital phase. Results showed that 95.3% of the assessments made by prehospital personnel agreed with those made by a highly-trained nurse observer, despite slight variations in assessment techniques. The results have implications for prehospital field use of the TS.

Diagnosis-Related Groups↗
PubMed1984

Interleukin 1 secretion by human monocytes stimulated by the isolated polysaccharide region of the Bordetella pertussis endotoxin.

The isolated polysaccharide chain, PS-1, of the Bordetella pertussis endotoxin was examined by isoelectric focusing, SDS-polyacrylamide gel electrophoresis and gel filtration for heterogeneity and for possible contamination by the parent endotoxin. This polysaccharide, previously found to be a very potent, macrophage-dependent, polyclonal B-cell activator and to mediate the specific binding of the endotoxin to macrophages, stimulated the interleukin 1 (IL 1) secretion by human monocytes; its potency was similar to that measured for the endotoxin. It was concluded that endotoxin-induced IL 1 production may be initiated by the interaction of the polysaccharide chain of the B. pertussis endotoxin and a specific structure present on macrophages.

Adult↗
PubMed1984

Structure of the terminal reducing heptasaccharide of polysaccharide 1 isolated from the Bordetella pertussis endotoxin.

The tetrasaccharide beta-D-glucopyranosyl-(1,3)-beta-D-glucopyranuronyl-(1, 2)-L-glycero-alpha-D-manno-heptopyranosyl-(1,5)-3-deoxy-D-manno-2- octulosonic acid was isolated after treatment of polysaccharide 1 of Bordetella pertussis endotoxin with nitrous acid. Taking into account previously identified di- and trisaccharide fragments and analytical data obtained for the intact polysaccharide 1, we present the structure of a heptasaccharide that is thought to represent the region immediately adjacent to the hydrophobic (lipid A) moiety of lipopolysaccharide 1 of the B. pertussis endotoxin. This heptasaccharide represents 50 to 60% of the complete polysaccharide structure.

Bordetella pertussis↗
PubMed1983

Fertilization of amphibian eggs: a comparison of electrical responses between anurans and urodeles.

In Pleurodeles waltl and Ambystoma mexicanum, which exhibit physiological polyspermy, the membrane potential in most eggs did not change in any consistent pattern during 45 min after fertilization; in some cases, a slow hyperpolarization began 5 to 15 min after insemination and continued for 10-15 min. These eggs then slowly depolarized, reaching a stable value of -10 to +10 mV, about 45 min after fertilization. Membranes of eggs activated by A23187 or by electrical stimulus showed a similar behavior. The diversity of responses does not correlate with the number of sperm fusing with the egg. Holding the membrane potential at a constant value between -40 and +40 mV during insemination did not prevent fertilization nor delay sperm-egg interactions. The fertilization or activation potential of Rana temporaria eggs consists of a rapid (1 sec) depolarization accompanied by a sudden decrease in membrane resistance. The activation potential can be triggered by A23187 and by calcium iontophoresis; its amplitude depends on the (Cl-)0 and to a lesser extent on the (Na+)0. Fertilization was prevented when the membrane potential was clamped above +15 mV. However, slowing the rise time (5 to 8 sec instead of 1 sec) and reducing the amplitude (10-20 mV instead of 40-60 mV) of the fertilization potential, both by injecting negative current, never induced polyspermy.

Amphibians↗
PubMed1982

Isolation of a trisaccharide containing 2-amino-2-deoxy-D-galacturonic acid from the Bordetella pertussis endotoxin.

4-O-(2-Amino-2-deoxy-alpha-D-glucopyranosyl-6-O-(2-amino-2-deoxy-alpha-D-galactopyranuronyl)-D-glucopyranose, a branched-chain trisaccharide, was isolated after hydrolysis of Bordetella pertussis endotoxin with 4 M HCl for 1 h at 100 degrees C. The trisaccharide was present in both polysaccharide moieties of the two constituent lipopolysaccharides of this endotoxin. Its structure was established by analysis of the 400-MHz nuclear magnetic resonance spectrum and by chemical and enzymatic degradation.

Bordetella pertussis↗
PubMed1982

Effects of butoprozine on ionic currents in frog atrial and ferret ventricular fibres. Comparison with amiodarone and verapamil.

The effects of butoprozine on cardiac membrane currents of frog atrial and ferret ventricular fibres were investigated in voltage clamp conditions by means of the double sucrose gap technique. Comparison was made with amiodarone and verapamil. Butoprozine was found to decrease the fast sodium and slow calcium inward currents and the delayed outward current in a dose-dependent manner. The reactivation kinetics of both inward currents were reduced by butoprozine. Amiodarone principally decreased the delayed outward current but high concentrations also depressed the inward currents. In the same way, small concentrations of verapamil inhibited the slow inward calcium current while high concentrations also affected the delayed outward and the fast inward sodium currents. The reactivation kinetics of both inward currents were reduced by amiodarone. These of the fast inward current remained unaffected by verapamil while these of the slow inward current were reduced or sometimes not appreciably changed. The effects of butoprozine on the ionic currents accounted for the modifications observed on the action potential and automaticity and this study allowed the understanding of the mechanisms by which the drug can exert its antiarrhythmic action. Some of them are common to amiodarone and verapamil.

Amiodarone↗
PubMed1982

Electrophysiological effects of butoprozine on isolated heart preparations. Comparison with amiodarone and verapamil.

The electrophysiological effects of butoprozine, a relatively new antiarrhythmic agent, were investigated in sheep cardiac Purkinje fibres using a microelectrode technique and in frog atrial and ferret ventricular fibres using a double sucrose gap technique. Comparison was made with amiodarone and verapamil. Butoprozine increased the action potential duration like amiodarone, depressed the plateau phase like verapamil and decreased the amplitude and the maximum rate of depolarization. Pacemaker activity in Purkinje fibres and repetitive activity in frog atrium were inhibited by the three drugs. The inhibition of automaticity was related to a reduction of the slope of diastolic depolarization in both tissues by butoprozine and amiodarone. The results confirm that butoprozine possesses a potent antiarrhythmic activity. It acts by mechanisms common to amiodarone and verapamil.

Action Potentials↗
PubMed1981

Post-operative neuropathic fractures in patients with myelomeningocele.

Neuropathic fractures are common after major surgical procedures to stabilize the hip or spine in patients with myelomeningocele. Complications resulting from such fractures are frequently observed. The fractures occur particularly in the more severely involved children and are associated with prolonged immobilization after surgery. The authors advise that all necessary surgery be done within the shortest possible time, and urge that prolonged immobilization be avoided if possible.

Child↗
PubMed1980

Biological activities of fragments derived from Bordetella pertussis endotoxin: isolation of a nontoxic, Shwartzman-negative lipid A possessing high adjuvant properties.

Endotoxin from fresly sedimented Bordetella pertussis cells, isolated by the phenol/water procedure when submitted to kinetically controlled, mild acidic hydrolysis released a polysaccharide (polysaccharide 1), a complex lipid (lipid X), and a glycolipid. When treated with somewhat stronger acid, the glycolipid yielded a second polysaccharide (polysaccharide 2) and another complex lipid (lipid A). The intact pertussis endotoxin had all the usual properties of endotoxins extracted from enteric bacteria. Lipid X and the intermediary glycolipid retained all the endotoxic properties of the unfractionated endotoxin. In lipid A, pyrogenicity was reduced to a very low level and toxicity and Shwartzman reactivity were absent; however, this fraction retained most of the endotoxin's antiviral activity, and its adjuvant power was considerably higher than that of the intact endotoxin. Lipid A elicited nonspecific resistance against challenge with certain bacteria, but not against others.

Adjuvants, Immunologic↗
PubMed1980

The results and complications of surgery for the paralytic hip and spine in myelomeningocele.

We have reviewed the results of operations to stabilise the paralytic hip and to correct and stabilise the deformed spine of children with myelomeningocele. Despite a high complication rate the spinal operations were frequently successful. The hip operations were less satisfactory, with stabilisation of the hip eventually achieved in 69 per cent of the patients and improved walking in only 27 per cent. We do not recommend that such operations be undertaken on the hips of children with a level of paralysis at L3 or above. If stabilisation is indicated multiple combined procedures produce the best result.

Child↗
PubMed1979

Natural history of the dislocated hip in spastic cerebral palsy.

A review was made of 88 adult institutionalized patients with spastic cerebral palsy and contractural deformity of the hips. 21 were untreated for dislocated hip, and 11 of these suffered from hip pain. The degree of pain was directly related to neurological maturity and to the coexistence of athetosis and spasticity. Decubitus ulcers and perineal care problems were more associated with contractures than with dislocation alone. It is concluded that dislocation and subluxation should be prevented by surgical means, but that surgical treatment of the already dislocated hip should be reserved for the neurologically mature and athetoid patient.

Adult↗
PubMed1979

Relationships between hormone-induced calcium release and 86rubidium uptake stimulation in starfish oocytes.

86Rubidium+ uptake, but not 86Rubidium efflux, is strongly stimulated after addition of the meiosis inducing hormone 1-methyladenine (1-MeAde) to prophase blocked oocytes of the starfish Marthasterias glacialis. This stimulation is a transient process which does not require the continuous presence of 1-MeAde and is elicited within 1 minute of contact. 1-MeAde and its biologically active structural analogs fully stimulate Rb+ uptake at concentrations which are about two orders of magnitude lower than those required to trigger meiosis reinitiation but which already release underthreshold levels of Ca2+ from the inner part of the plasma membrane. External Ca2+ concentrations effective in triggering meiosis reinitiation also stimulate Rb+ influx, while drugs like D600, theophyllin and caffein which suppress the hormone induced Ca2+ release, simultaneously preclude the stimulation of Rb+ uptake. Dithiothreitol (DTT) which mimicks 1-MeAde action in releasing Ca2+ and inducing meiosis acts both on the efflux and on active and passive Rb+ influxes. Ouabain, the classical inhibitor of the Na+, K+ pump does not preclude meiosis reinitiation under the influence of 1-MeAde, its agonists of mimetics. It suppresses the active component of Rb+ uptake both in control or stimulate oocytes. When applied only in preincubation before starting the hormone treatment, it cannot however inhibit the stimulation of Rb+ uptake, while basal pump inhibition is preserved. These results demonstrate that stimulation of the active Rb+ or K+ transport is not indispensable to meiosis reinitiation. They suggest moreover that the hormone induced Ca2+ release from the plasma membrane may be responsible for unmasking new ouabain sensitive transport sites.

Adenine↗