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Biomedical subjects

C Martin

Publications and source records attributed to C Martin.

At least 793 records · Page 44Linked to original sources
PubMed1990

[Psychologic factor in Menière's disease].

Although a number of authors have evoked a psychosomatic etiology for Ménière's disease, few works have dealt specifically with this subject. Forty-eight patients with authentic Ménière's disease underwent a series of psychometric self-evaluation determinations, in addition to a complete, repeated ENT examination. The first questionnaire, the SCL 90, explored the psychological profile. The second questionnaire, the QD 2 A, explored the depressive tendency. This study clearly showed that patients with Ménière's disease present a psychopathological profile which significantly differs to that of a reference population, particularly in terms of level of anxiety, depressive tendency and phobia. The latter points are of real practical importance, since they imply that improvements in Ménière's disease call for treatment of the phobic component in addition to the anxious-depressive component. Finally, there is an obvious correlation between the extent of hearing loss, in turn related to the frequency of vertigo attacks, and the severity of psychopathological disorders.

Adult↗
PubMed1990

[Influence of catheter type and site on infection incidence. Prevention techniques].

Relative risk of catheter-related sepsis varies according to the site and the catheter type chosen. Subclavian vein route is usually safer than internal jugular vein route. However internal jugular catheter can be tunnelled on the thorax which may decrease infections risk. Infection rate is very low during arterial cannulation whatever the site used, including femoral artery. The use of Swan-Ganz catheter is accompanied by a very low infection rate, despite repeated interventions on the catheter line. Prevention of infection is a major goal during vascular catheterization. A strict aseptic procedure must be used during placement of the line. Same aseptic precautions must be taken during every manipulation of the line. The best results are obtained when the management of the intravascular line is under the responsibility of a specialized "Catheter Team".

Asepsis↗
PubMed1990

[Outbreak of Staphylococcus aureus infections in an intensive care unit].

An outbreak of nosocomial staphylococcal infections occurred over a six months period in an intensive care unit. This outbreak was caused by a single phage type of oxacillin resistant Staphylococcus aureus (SA) which infected ten patients. Six patients had bacteremia with infected catheter, two with urinary tract infection and two patients had a pneumonia. The median SAPS was 13. Four patients died. An epidemiologic study was performed to know SA nasal carriage prevalence of patients and hospital staff. There were seven isolates of SA from 83 hospital staff and three from 20 patients, all with the same phage type 77. Hospital staff and patients colonisation with a same SA strain is a potential reservoir for epidemic nosocomial infections. Prophylactic measures are hygienic measures like handwashing, but perhaps also patients and staff selective decontamination with topical antimicrobial substances.

Cross Infection↗
PubMed1990

[Tissue penetration of single-dose cefotetan used for antibiotic prophylaxis in colorectal surgery].

Pharmacokinetics and tissue penetration of cefotetan were studied after a single injection of 2 g for antibiotic prophylaxis in colo-rectal surgery. Beta half-life was 4.3 +/- 1 h, total body clearance was 0.74 +/- 0.2 ml/kg/min and volume of distribution was 270 +/- 76 ml/kg. At time of laparotomy, cefotetan concentration was 14.2 +/- 7 micrograms/g in abdominal wall fat and 16.4 +/- 1 micrograms/g in epiploic fat. In the colonic wall, cefotetan concentration was 33.3 +/- 16 micrograms/g. At time of abdominal closure, cefotetan concentrations were 6.3 +/- 3 micrograms/g in the abdominal wall fat and 6.1 +/- 4 micrograms/g in the epiploic fat.

Abdominal Muscles↗
PubMed1990

Identification and properties of voltage-sensitive sodium channels in smooth muscle cells from pregnant rat myometrium.

Saturable high and low affinity binding sites for [3H]saxitoxin were identified in myometrial membranes of pregnant rats, with dissociation constants of 0.53 and 27 nM, respectively. The maximal binding capacity of the low affinity binding sites was about 10 times higher than that of the high affinity binding sites. The dissociation constants obtained from association and dissociation kinetics of [3H]saxitoxin were similar to those obtained from equilibrium binding. Saxitoxin and tetrodotoxin specifically displaced [3H]saxitoxin binding at both types of sites. Isradipine (1-10 microM) and amiloride (50-100 microM) were without effect on the binding of [3H]saxitoxin. At high concentrations (10-100 microM), veratridine induced a partial inhibition of [3H]saxitoxin binding. In dispersed myometrial cells, [3H]saxitoxin binding revealed the presence of both high and low affinity binding sites, with KD values similar to those obtained in myometrial membranes. Sodium currents were studied in both freshly dispersed and cultured myometrial cells in the presence of veratridine (100 microM), using the whole-cell patch-clamp technique. Steady state inactivation curves indicated that sodium channels were available at negative membrane potentials (between -110 and -40 mV). Isradipine (1-10 microM) and amiloride (50-100 microM) were without effect on the sodium current. Applications of saxitoxin or tetrodotoxin inhibited the amplitude of the sodium current in a concentration-dependent manner. The concentrations of saxitoxin and tetrodotoxin producing half-maximal inhibition were 1.4 and 8.8 nM, respectively. Although the IC50 values for saxitoxin and tetrodotoxin found from electrophysiological experiments are not identical to the equilibrium dissociation constants for the high and low affinity sites found from binding experiments, these results suggested that binding of the neurotoxins to the high affinity sites may be involved in their inhibitory effects on sodium channels. Furthermore, low affinity binding sites may be associated with a non-functional subtype of sodium channels in myometrial cells.

Action Potentials↗
PubMed1990

[Detection of beta-lactamases in the Bacteroides fragilis group].

One hundred and thirty three strains of Bacteroides fragilis group isolated from clinical specimen were tested for beta-lactamase activity against five beta-lactam antibiotics, ampicillin, cefaloridin, cefuroxime, cefotaxime and cefoxitin. The Minimal Inhibitory Concentration of antibiotics was determined using the agar dilution method. Beta-lactamase production was detected by a microbiological method in 128 of the 133 (96%) strains. The detected beta-lactamases had a broad-spectrum activity, hydrolyzing both penicillins and cephalosporins (101 strains). Some strains had a wide activity against beta-lactam antibiotics, including cefoxitin (7 strains); among these strains, 3 were found hydrolyzing imipenem.

Anti-Bacterial Agents↗
PubMed1990

[Modification of ofloxacin pharmacokinetics induced by prolonged mechanical ventilation].

The pharmacokinetics of ofloxacin was studied in 12 intensive care patients, 6 of whom being under mechanical ventilation. All patients had a creatinine clearance greater than 60 ml/min/1.73 m2 and they were given 3 mg/kg. IV ofloxacin within 30 mn, with a twice daily regimen for 7 days. Pharmacokinetic studies were performed on day 1 (D1) and 7 (D7). Between D1 and D7 a significant increase in T 1/2 beta, AUC and blood levels were observed together with a decrease in total body clearance. Creatinine clearance was not modified between D1 and D7 but ofloxacin renal clearance was considerably altered. Abnormalities in ofloxacin renal tubular secretion may account for the drug cumulation which was observed during repeated administration in intensive care patients.

Aged↗
PubMed1989

Acetylated low density lipoproteins promote the release and metabolism of arachidonic acid by murine macrophages.

It has been postulated that the ratio of prostacyclin/thromboxane A2 in the blood is an important marker for atherosclerosis. We studied the role of the Acetylated Low Density Lipoprotein (Acetyl-LDL) on the arachidonic acid metabolism in macrophages, the progenitor of the foam-cells in atheroma. When stimulated by Acetyl-LDL, macrophage released and metabolized arachidonic acid. This effect was time- and dose-dependent. Only 50% of the Acetyl-LDL-induced arachidonic acid released was metabolized while more than 90% of zymosan or A23187 induced arachidonic acid released was metabolized. Furthermore, when the macrophages were stimulated by Acetyl-LDL, a decrease of prostaglandin E2 and an increase of the levels of prostacyclin and thromboxane were noted. The implications of these observations in the pathogenesis of atherosclerosis are discussed.

Acetylation↗
PubMed1989

Presynaptic effect of gamma-aminobutyric acid on the inhibitory nerve and nerve terminals in the crayfish neuromuscular junction.

Experiments were carried out in voltage-clamped fibres of the opener muscle of the first walking leg or claw of small crayfish. Repetitive discharges in the inhibitory nerve innervating the muscle were induced by adding serotonin (10(-6) mol/l) and forskolin (10(-4) mol/l) to the superfusate. Rates of nerve discharge were determined by recording nerve evoked inhibitory postsynaptic currents (IPSCs) in the voltage-clamped muscle fibre. Subsequently, the effect of gamma-aminobutyric acid (GABA) on the rate of IPSCs in normal and Cl- -deficient superfusate was investigated. In normal superfusate GABA (10(-5) mol/l) abolished the IPSCs whereas in Cl- -deficient superfusate GABA (10(-4) mol/l) enhanced the rate of IPSCs. Moreover, in Cl- -deficient superfusate the rate of asynchronous quantal release of inhibitory transmitter could be enhanced by GABA. The results indicate that in the crayfish neuromuscular junction the inhibitory axon is supplied with GABA receptors which may affect (a) axonal excitation and (b) quantal output at the inhibitory axon terminals.

Action Potentials↗
PubMed1989

Genome juggling by transposons: Tam3-induced rearrangements in Antirrhinum majus.

Transposable elements are well known for their ability to generate large- and small-scale rearrangements of the sequences flanking their insertion sites. These include deletions, inversions, and duplications. Tam3, a transposon from the Snapdragon (Antirrhinum majus), is highly active in the generation of such rearrangements. We have analysed a number of Tam3-induced rearrangements at the nivea (niv) locus by Southern blotting, cloning, and sequence determination. The data obtained from these analyses have led to an understanding of the mechanisms by which these complex alleles were formed. We have shown that the primary rearrangements usually occur without excision of the element and therefore result from aberrant transposition attempts. Subsequent rearrangements may occur on excision of the element. Finally, we suggest how the analysis of such rearrangements may not only provide information about Tam3 transposition but also show how transposon-induced rearrangements may influence the structure and function of the genome as a whole.

Base Sequence↗
PubMed1989

Activity of the transposon Tam3 in Antirrhinum and tobacco: possible role of DNA methylation.

The transposon Tam3 from Antirrhinum majus can transpose in a heterologous host (Nicotiana tabacum); thus the element is autonomous, probably encoding the specific information required for its own transposition. In transgenic tobacco Tam3 rapidly becomes methylated at its ends whilst adjacent flanking sequences remain hypomethylated. This methylation may account for our failure to detect Tam3 transposition in the progeny of transgenic tobacco. Treatment with the inhibitor of cytosine methylation, 5 aza-cytosine appeared to induce transposon related activity at a low level. In Antirrhinum methylation also appears to be associated with inactivation of Tam3 copies.

DNA↗