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Biomedical subjects

L Gutmann

Publications and source records attributed to L Gutmann.

At least 109 records · Page 6Linked to original sources
PubMed1994

Treatment of spastic gait in cerebral palsy.

The most common presentation of cerebral palsy is spastic diplegia, which in severe cases can impede nursing care and in less severe cases can impair a child's ability to move around with facility. A procedure has been developed to decrease spasticity in which there is selective section of portions of the dorsal roots L2-S2. In a series of such operations in 19 children with spastic diplegia, we were able to decrease their spasticity significantly with resultant improvement in motor function and self care. There were no significant complications and patient and family satisfaction was high. Our experiences further confirm existing evidence that this procedure is very helpful and highly recommended for selected children with spasticity due to cerebral palsy.

Cerebral Palsy↗
PubMed1993

AAEM minimonograph #2: important anomalous innervations of the extremities.

Anomalous innervations of the extremities are common and influence the interpretation of electrophysiologic studies in normal patients and those with peripheral nerve lesions. The following anomalous innervations are reviewed: median to ulnar nerve communication; ulnar to median nerve communication; variations in the innervation of intrinsic muscles of the hand; accessory deep peroneal nerve; and tibial to peroneal nerve communication. The electrophysiologic recognition of these anomalies and the manner in which they affect the interpretation of electrodiagnostic studies in various conditions is emphasized.

Action Potentials↗
PubMed1993

Lambert-Eaton myasthenic syndrome with prominent postexercise exhaustion.

A 66-year-old man with Lambert-Eaton myasthenic syndrome, polyneuropathy, and small cell lung cancer, developed profound muscle weakness with a prolonged period of ventilatory dependency. Electrophysiological studies demonstrated very small compound muscle action potentials in response to supramaximal nerve stimulation, limited tetanic and postexercise facilitation, and prolonged prominent postexercise exhaustion (40-60% of baseline value) persisting up to 20 minutes. It is hypothesized that these changes may reflect both a severe defect in acetylcholine release and decreased availability of releasible acetylcholine from the terminal axon.

Aged↗
PubMed1993

Triple combination penicillin-vancomycin-gentamicin for experimental endocarditis caused by a highly penicillin-and glycopeptide-resistant isolate of Enterococcus faecium.

A combination of low-dose penicillin (75,000 IU/kg twice daily [b.i.d.]) vancomycin (30 mg/kg b.i.d.) and gentamicin (6 mg/kg b.i.d.) has been shown to be as effective as a combination of high-dose penicillin (500,000 IU/kg b.i.d.) and gentamicin (6 mg/kg b.i.d.) in the treatment of rabbit endocarditis caused by an Enterococcus faecium strain moderately resistant to beta-lactams and highly resistant to glycopeptides. The same regimens were evaluated against an E. faecium strain highly resistant to both penicillin (MIC, 128 micrograms/mL) and vancomycin (MIC, 512 micrograms/mL). High doses of penicillin-gentamicin and vancomycin-gentamicin had no effect in in vitro killing-curve studies or in rabbits after treatment for 5 days. High doses of penicillin-vancomycin were only bacteriostatic in killing curves and provided a small reduction in the bacterial titers of the vegetations. In contrast, high-dose penicillin-vancomycin-gentamicin was bactericidal in vitro and highly effective in treating rabbits. However, the emergence of a bacterial subpopulation resistant to the synergistic effect of penicillin and vancomycin could reduce the clinical utility of this combination.

Animals↗
PubMed1993

Activity of the beta-lactamase inhibitor BRL 42715 against cephalosporinases produced by Enterobacteriaceae.

BRL 42715, a novel beta-lactamase inhibitor, was evaluated for its capacity to inhibit cephalosporinases. BRL 42715 was effective in potentiating the activity of antibiotics against clinical isolates of Enterobacteriaceae that produced high levels of cephalosporinases. This correlated well with the very low 50% inhibition values (< 0.004 mg/L) of BRL 42715 for cephalosporinases extracted from different species. When compared in vitro to clavulanic acid, sulbactam, and tazobactam, BRL 42715 was the most efficient inhibitor of cephalosporinase.

Anti-Bacterial Agents↗
PubMed1993

Characterization of ceftriaxone-resistant Enterobacteriaceae: a multicentre study in 26 French hospitals. Vigil'Roc Study Group.

During a multicentre study performed in 26 French hospitals, 287 (3.2%) of 9038 Enterobacteriaceae isolated, mainly Enterobacter spp., Serratia spp., Citrobacter spp. and Klebsiella spp. were classified as ceftriaxone resistant on the basis of an MIC > 4 mg/L or the presence of an extended-spectrum beta-lactamase. Extended-spectrum beta-lactamase was present mainly in Klebsiella pneumoniae (65 strains, 10.2%) and very rarely in Escherichia coli, Proteus mirabilis, Klebsiella oxytoca, Citrobacter spp. and Enterobacter spp. The extended-spectrum beta-lactamases conferred low-level resistance to ceftriaxone in nearly 60% of the strains harbouring them, emphasizing the need for routine testing for the presence of these enzymes. Among transconjugants three types of extended-spectrum beta-lactamase were identified. Those resembling TEM-3 were the most common, but TEM-21, and SHV-4 were also found. Clavulanate and to a lesser extent sulbactam inhibited all the extended-spectrum beta-lactamases encountered in this study.

Ceftriaxone↗
PubMed1993

Novel gyrA point mutation in a strain of Escherichia coli resistant to fluoroquinolones but not to nalidixic acid.

We have previously described a clinical isolate of Escherichia coli (Q2) that is highly resistant to fluoroquinolones (MIC of ciprofloxacin, 16 micrograms/ml) but susceptible to nalidixic acid (MIC of nalidixic acid, 4 micrograms/ml) (N. Moniot-Ville, J. Guibert, N. Moreau, J.F. Acar, E. Collatz, and L. Gutmann, Antimicrob. Agents Chemother. 35:519-523, 1991). Transformation of strain Q2 with a plasmid carrying the wild-type gyrA gene from E. coli K-12(pAFF801) resulted in a 32-fold decrease in the MIC of ciprofloxacin, suggesting that at least one mutation in gyrA was involved in the resistance of Q2. Intragenic gyrA fragments of 668 and 2,500 bp from strain Q2 were amplified by the polymerase chain reaction. We sequenced the 668-bp fragment and identified a single novel point mutation (transition from G to A at position 242), leading to an amino acid substitution (Gly-81 to Asp) in the gyrase A subunit. We constructed hybrid plasmids by substituting either the 668-bp fragment or the 2,500-bp fragment from Q2 DNA, both of which contained the gyrA point mutation, for the corresponding fragments in wild-type gyrA (2,625 bp) of E. coli K-12. When introduced into E. coli KNK453 (gyrA temperature sensitive), both plasmids conferred an eightfold increase in the MIC of ciprofloxacin, but only a twofold increase in the MIC of nalidixic acid. When introduced into E. coli Q2, neither plasmid conferred any change in the MICs of ciprofloxacin or nalidixic acid, suggesting that only the point mutation found in gyrA was involved in the resistance that we observed.

Anti-Infective Agents↗
PubMed1993

Penicillin-binding proteins of Rhodococcus equi: potential role in resistance to imipenem.

Rhodococcus equi is a gram-positive coccobacillus which, like other members of the order Actinomycetales, is increasingly reported as an opportunistic pathogen in patients with AIDS. The use of combinations of antibiotics that include imipenem (IMP) has been suggested for the treatment of patients infected with R. equi. An antagonism between IMP, meropenem, cefoxitin, ceftriaxone, moxalactam, and oxacillin and other beta-lactams, such as penicillin, amoxicillin, cephalothin, and ticarcillin, was detected in vitro both on Mueller-Hinton agar and in broth for all 10 IMP-susceptible R. equi strains examined. To study the mechanism of the antagonism between beta-lactams, a mutant with decreased susceptibility to IMP (isolate IpR) was selected in vitro from a susceptible clinical isolate of R. equi (isolate IpS). IpR exhibited decreased susceptibility to IMP, meropenem, cefoxitin, ceftriaxone, moxalactam, and oxacillin but not to penicillin, amoxicillin, cephalothin, or ticarcillin. No beta-lactamase was found in IpS, IpS cultured with antagonistic beta-lactams, or IpR strains. Labeling of penicillin-binding proteins (PBPs) revealed four PBPs with molecular masses of ca. 59, 56, 43, and 26 kDa in IpS. In IpR, PBP 3 disappeared and was replaced by PBP 3a of 40 kDa. The 50% saturation of PBP 3 and PBP 3a by the carbapenems correlated with the MICs of these antibiotics, respectively, for IpS and IpR strains. However, PBP 3a was not detected in IpS when IpS was cultured in the presence of beta-lactams, with which antagonism was observed. The present work describes the PBPs of R. equi and reports that IMP resistance in R. equi is related to an altered PBP pattern.

Anti-Bacterial Agents↗
PubMed1993

Mechanisms of resistance to quinolones.

Mechanisms of resistance to the quinolones have been described for several bacterial species, but mainly for Escherichia coli and Staphylococcus aureus. Two principal mechanisms have been described: 1) alteration of the DNA gyrase, which is the target site of the quinolones; and 2) diminished accumulation in the cell as a result of either decreased uptake or increased efflux. Alteration of DNA gyrase is usually the result of a mutation in the gyrA, or more rarely, the gyrB gene. All substitutions in subunit A of the gyrase are located in the 67 to 106 amino-acid domain and are clustered around Ser-83 in E. coli and Ser-84 in S. aureus. A decrease in uptake has been described for Gram-negative bacteria such as Enterobacteriaceae and Pseudomonas aeruginosa. It has almost always been correlated with a modified electrophoretic profile of outer membrane proteins of the quinolone-resistant mutants. In E. coli, a decrease in OmpF seemed to be linked to the activation of the micF operon in most of the mutants described. These mutants were cross-resistant to unrelated antibiotics, such as trimethoprim, chloramphenicol, tetracycline, and some beta-lactams. In all these mutants the normal or enhanced efflux of quinolones increased the level of resistance. Enhanced efflux has been described as the second mechanism of resistance in S. aureus. Acquired resistance to the quinolones was thought, until recently, to result from chromosomal mutation. Plasmid-mediated resistance associated with an enhanced efflux has been described in S. aureus, but this needs to be confirmed. When a high level of resistance is observed, 2 or 3 mechanisms may be involved.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Quinolones↗
PubMed1992

A silent carbapenemase gene in strains of Bacteroides fragilis can be expressed after a one-step mutation.

High-level carbapenem-resistant (CpmR) mutants, with MICs for imipenem and carbapenem of greater than 128 micrograms/ml, were selected in vitro from four carbapenem-susceptible (CpmS) clinical isolates of Bacteroides fragilis. The CpmS strains produced very low levels of beta-lactamase activity, which was increased approx. 50- to 100-fold in the CpmR mutants. Isoelectric focussing and enzyme kinetic analysis (Km and Vrel) of the 'carbapenemases' from the CpmR mutants and similarly resistant clinical isolates suggested a close relatedness of the enzymes. A probe covering most of the cfiA gene encoding such an enzyme (Thompson, J.S. and Malamy, M.H. (1990) J. Bacteriol. 172, 2584-2593) hybridized with DNA from the CpmR mutants, their CpmS parental strains as well as clinical CpmR isolates, but not from randomly chosen carbapenem-susceptible strains. The possibility is considered that mutations leading to expression of the silent carbapenemase gene, and thereby to clinically relevant carbapenem resistance, may also occur in the clinical setting.

Bacterial Outer Membrane Proteins↗
PubMed1992

Replacement of the essential penicillin-binding protein 5 by high-molecular mass PBPs may explain vancomycin-beta-lactam synergy in low-level vancomycin-resistant Enterococcus faecium D366.

The mechanism of synergy between vancomycin and penicillin, as well as other beta-lactam antibiotics, was examined in a penicillin-resistant E. faecium (D366) expressing an inducible low-level resistance to vancomycin. It was demonstrated that penicillin per se was not able to reduce the inducible expression of the 39.5-kDa protein (VANB) or the carboxypeptidase activity which are involved in the mechanism of vancomycin resistance of this strain. Assays of competition between 3H-benzylpenicillin and diverse beta-lactam antibiotics suggested as the most likely explanation of the synergy that, once vancomycin resistance has been induced, the high-molecular mass penicillin-binding proteins (PBPs), and possibly PBP1 in particular, which have a high affinity for beta-lactam antibiotics, take over the role of the low-affinity PBP5 which is, in the non-induced strain, responsible for beta-lactam resistance.

Bacterial Proteins↗