In vitro testing of the antibacterial activity of fosfomycin trometamol against urinary pathogens.

The activity of fosfomycin trometamol (FOT) was compared with that of cotrimoxazole (COT) and norfloxacin (NOR) using urine as medium and 10(7) bacteria as inoculum, conditions as close as those found by the administration of the drugs in vivo during the course of a urinary tract infection. The minimum inhibitory concentrations (MIC) of all antibiotics against 100 strains isolated from urinary tract infections were found to be higher than the breakpoint. Concentrations of FOT corresponding to mean and maximal values found in urine after single dose administration within the 0-48 h interval killed the great majority of strains.

Bacteriostatic and bactericidal activities of beta-lactams against Streptococcus (Enterococcus) faecium are associated with saturation of different penicillin-binding proteins.

The MICs and MBCs of benzylpenicillin, ampicillin, cefotaxime, and methicillin were evaluated against a Streptococcus (Enterococcus) faecium wild-type strain and against three mutants hyperproducing PBP 5 in cells incubated at both optimal and suboptimal temperatures. In the wild-type strain grown at optimal temperature, the MBCs of all beta-lactams were significantly greater than the MICs (bacteriostatic effect). As opposed to this, in the same cells grown at suboptimal temperature and in the mutants hyperproducing PBP 5 at all temperatures, the MICs of all antibiotics coincided with the MBCs (bactericidal effect).

Streptococcus faecium mutants that are temperature sensitive for cell growth and show alterations in penicillin-binding proteins.

The penicillin-binding proteins (PBPs) of 209 cell division (or growth) temperature-sensitive mutants of Streptococcus faecium were analyzed in this study. A total of nine strains showed either constitutive or temperature-sensitive conditional damage in the PBPs. Analysis of these nine strains yielded the following results: one carried a PBP 1 constitutively showing a lower molecular weight; one constitutively lacked PBP 2; two lacked PBP 3 at 42 degrees C, but not at 30 degrees C; one was normal at 30 degrees C but at 42 degrees C lacked PBP 3 and overproduced PBP 5; two were normal at 42 degrees C and lacked PBP 5 at 30 degrees C; one constitutively lacked PBP 5; and one carried a PBP 6 constitutively split in two bands.

Changes in penicillin-binding proteins during the life cycle of Micromonospora.

The penicillin-binding proteins (PBPs) of Micromonospora were studied. Only one PBP (48,000 mol weight) was found in membranes isolated from primary mycelia, whereas three PBPs were observed in secondary mycelia and designated PBP 1 (89,000 mol weight), PBP2 (69,000) and PBP3 (48,000). Both the unique PBP produced by primary mycelia and PBP3 of secondary mycelia had the same affinity for penicillin which was higher than that of PBP2 and 3.

Superficial temporal artery to proximal middle cerebral artery anastomosis: clinical and angiographic long term results.

Anastomosis of the superficial temporal artery (STA) with a proximal segment of the middle cerebral artery (MCA) has been proposed as a new cerebral revascularization technique alternative to the conventional bypass on the cortical surface. We introduced this procedure in our surgical practice in 1982 for patients with internal carotid artery (ICA) aneurysms not suitable for direct repair in whom occlusion of the ICA is considered necessary. One patient died because a conventional STA-MCA bypass did not prevent a major stroke caused by a therapeutic ICA occlusion.

Role of EEG monitoring and cross-clamping duration in carotid endarterectomy.

The usefulness of electroencephalographic (EEG) monitoring as well as the significance of the period of cross clamping in carotid endarterectomy have not been completely defined. In particular, the clinical importance of major EEG changes has not been fully investigated and some recent studies seem to indicate that the method has little value. As to the duration of cross clamping, there is strong evidence that occlusion times of about 15 minutes are tolerated under general anesthesia, but no information is available regarding longer periods of occlusion.

Lung cancer screening: the Mayo program.

The National Cancer Institute has sponsored three randomized controlled trials of screening for early lung cancer in large, high-risk populations to determine whether lung cancer detection can be improved by adding sputum cytological screening every 4 months to chest roentgenography done either yearly or every 4 months; and lung cancer mortality can be significantly reduced by this type of screening program, followed by appropriate treatment. Results of the three trials suggest that sputum cytology alone detects 15% to 20% of lung cancers, almost all of which are squamous cancers with a favorable prognosis; and chest roentgenography may be a more effective test for early-stage lung cancer than previous reports have suggested. Nevertheless, results of the randomized trial conducted at the Mayo Clinic showed that offering both procedures to high-risk outpatients every 4 months conferred no mortality advantage over standard medical practice that included recommended annual testing.

Comparison of effects of penicillin minimal inhibitory and sub-inhibitory concentration on Staphylococcus aureus and Streptococcus faecium does not support the view that antibiotic sub-inhibitory concentrations can specifically interfere with bacterial virulence.

The effect of minimal (MIC) and sub-minimal (sub-MIC) inhibitory concentrations of penicillin on Staphylococcus aureus and Streptococcus faecium were compared. It was found that similar alterations in both cell shape and ultrastructure were found in the presence of penicillin MIC and sub-MICs, the only difference being that while in the presence of penicillin MIC all individual cells were altered, in the presence of sub-MICs the damaged portion was smaller the lower the penicillin concentration and the longer the incubation time. By testing the effect of inoculum size on the penicillin MIC, it was found that penicillin concentrations, which were sub-MICs for rather dense population, turned out to be the MICs for lower density populations.

In Streptococcus faecium penicillin-binding protein 5 alone is sufficient for growth at sub-maximal but not at maximal rate.

In Streptococcus faecium inhibition by both benzylpenicillin and cefotaxime of cells growing at maximal and at reduced rates was associated with saturation of different penicillin-binding proteins. Cells growing at reduced rates were not inhibited by benzylpenicillin concentrations that saturated all penicillin-binding proteins except penicillin-binding protein 5, but did stop growing when this protein was saturated.

Purification of Streptococcus faecium penicillin binding protein 5, a multifunctional penicillin-binding protein.

Penicillin-binding protein 5 of Streptococcus faecium has been solubilized and partially separated from other membrane proteins by covalent affinity chromatography. PBP 5 was successively purified to homogeneity by resolution on SDS-polyacrylamide gel, elution and renaturation of penicillin-binding activity. The purification procedure does not alter the properties that the protein exhibits in the membranous environment.

Transition from resistance to hypersusceptibility to beta-lactam antibiotics associated with loss of a low-affinity penicillin-binding protein in a Streptococcus faecium mutant highly resistant to penicillin.

Penicillin-binding protein (PBP) 5 of Streptococcus faecium has been shown to have a very low affinity for penicillin, and this PBP was suggested to be responsible for both the natural low susceptibility and high resistance to the antibiotic in this species (R. Fontana, R. Cerini, P.

Different staphylococcal species contain various numbers of penicillin-binding proteins ranging from four (Staphylococcus aureus) to only one (Staphylococcus hyicus).

The penicillin-binding proteins of a total of 25 staphylococcal strains belonging to five different species were analyzed. All strains of the same species showed an identical penicillin-binding protein pattern which clearly differed from that of strains of the other species. Staphylococcus aureus, Staphylococcus intermedius, Staphylococcus simulans, and the dolphin strains were found to contain two to four penicillin-binding proteins.

Hematin-catalyzed epoxidation of 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene by polyunsaturated fatty acid hydroperoxides.

Hematin catalyzes the epoxidation of 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP-7,8-diol) by 13-hydroperoxy-9-cis,11-trans-octadecadienoic acid and other fatty acid hydroperoxides in the presence of detergent. The major oxidation product is the anti-dihydrodiolepoxide and the minor product is the syn-dihydrodiolepoxide. (+)-BP-7,8-diol is oxidized to (-)-anti-diolepoxide and (+)-syn-diolepoxide whereas (-)-BP-7,8-diol is oxidized to (+)-anti-diolepoxide and (-)-syn-diolepoxide.

Regulation of penicillin-binding protein activity: description of a methicillin-inducible penicillin-binding protein in Staphylococcus aureus.

The penicillin-binding proteins (PBPs) of two methicillin-resistant strains of Staphylococcus aureus (R2 and R1) were analyzed in cells grown in the absence and in the presence of methicillin. Under the former condition, strain R2 showed the typical PBP pattern of beta-lactam-susceptible strains, while strain R1 showed a markedly increased amount of PBP-3. Under the latter condition, on the other hand, a novel PBP (PBP-2a) located between PBP-2 and -3 was detected in strain R2, while strain R1 appeared to synthesize an even greater amount of PBP-3, in respect to untreated cells.

Functional classification of bronchial carinae.

Extensive classifications have been in use to describe the bronchial tree; however, the lack of uniform nomenclature to describe the carinae which separate the various bronchi has led to the use of lengthy and often confusing terminologies in reporting and understanding bronchoscopic findings. We have developed a practical classification of main bronchial carinae and suggest the use of abbreviations to describe them. The newer nomenclature is designed to help improve clinical communication, especially with regard to bronchoscopic findings and their clinical implications, among physicians who specialize in pulmonary diseases.

The National Cancer Institute Cooperative Early Lung Cancer Detection Program. Results of the initial screen (prevalence). Early lung cancer detection: Introduction.

This introduction provides a description of 3 cooperating studies on Screening for Early Lung Cancer conducted under the auspices of the National Cancer Institute. The next 3 reports detail the unique aspects and results of the individual screening studies. The final presentation summarizes the initial ("prevalence") screening for all 3 centers (approximately 30,000 men), and gives our conclusions.

Division of temperature-sensitive Streptococcus faecium mutants after return to the permissive temperature.

The regrowth of 27 temperature-sensitive division mutants of Streptococcus faecium ATCC 9790 was examined after various periods of incubation at the nonpermissive temperature. Several of the mutants blocked at various stages of septum formation or of daughter-cell separation divided in a partially or completely synchronous way after a short incubation at the nonpermissive temperature. All four lytic mutants blocked early in the cell division cycle divided at a normal rate after a brief lag.

Early lung cancer detection: results of the initial (prevalence) radiologic and cytologic screening in the Mayo Clinic study.

The initial (prevalence) radiologic and cytologic screening for lung cancer in the Mayo Clinic study (Mayo Lung Project) involved 10,933 outpatients. All were men at high risk for lung cancer, but none were suspected of having it when they entered the Mayo Clinic. Screening identified 91 lung cancers (8.