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Biomedical subjects

R Scotti

Publications and source records attributed to R Scotti.

At least 73 records · Page 4Linked to original sources
PubMed1988

Direct detection of paramagnetic species in adriamycin perfused rat hearts.

Direct detection of paramagnetic species in control and adriamycin-perfused rat hearts has been carried out. Depending on the flow rate of the perfusion solution (8,4,2 and 1 ml/min) different paramagnetic species were observed: Fe(III)(g = 2.12) at 4 ml/min; three types of oxygen centered radicals of which two in control hearts (g = 2.05 g = 2.038 g = g = 2.008) and the third one (g = 2.03 g = 2.005) in adriamycin perfused hearts, at 2 ml/min. The latter radical was the only one observed at perfusion rate of 1 ml/min both in control and adriamycin treated systems. A relationship between the intracellular enzymatic reductive activation of the anthracycline and the occurrence of ischemic conditions (4,2 and 1 ml/min) in myocardial tissues is proposed basing on the relative amounts of the paramagnetic species above mentioned.

Animals↗
PubMed1988

Bactericidal activity of teicoplanin in an in-vitro two-compartment kinetic model.

The bactericidal activity of teicoplanin was studied in a model system in which antibiotic concentration is continuously varied. A two-compartment open model was used to reproduce, in vitro serum pharmacokinetics of teicoplanin in humans during 24 h after iv administration. Staphylococcal and streptococcal strains of various species were tested. Teicoplanin showed rapid killing of Staphylococcus epidermidis and Staph. hominis. All strains of Staph. epidermidis were rapidly killed in spite of the high MIC values (4-16 mg/l). The killing effect against Staph. haemolyticus was less rapid and marked than against Staph. epidermidis, with strain to strain variation. A 99.9% kill was achieved for most strains within 22 h, but with other isolates regrowth occurred which was due to the presence of highly resistant cells in the original population. Other staphylococci (Staph. aureus, Staph. saprophyticus) and Streptococcus pyogenes, Str. bovis and Str. salivarius were reduced by 99.9% within 22 h. Bactericidal activity against other streptococci (Str. mutans, Str. agalactiae, Str. faecalis, Str. faecium) was less marked; against Str. sanguis teicoplanin was bacteriostatic.

Anti-Bacterial Agents↗
PubMed1988

A40926 aglycone and pseudoaglycones: preparation and biological activity.

A40926 antibiotics are new glycopeptides which are much more active than other members of this class against Neisseria gonorrhoeae. Their activity against Gram-positive bacteria, including coagulase-negative Staphylococci, is similar to that of other glycopeptides. An A40926 preparation containing factors A and B ("A40926 A + B complex") was hydrolyzed to the aglycone and to the mannosyl and N-acylaminoglucuronyl aglycones. The mannosyl aglycone and the aglycone were less active than A40926 A + B complex against Streptococci and Gram-positive anaerobes and lost the anti-gonorrheal activity. In contrast, the N-acylaminoglucuronyl aglycones were as active as the parent complex against these Gram-positive bacteria and were moderately active against N. gonorrhoeae. The aglycone and, even more so, the N-acylaminoglucuronyl aglycones, had better activity than the parent complex against coagulase-negative Staphylococci. In experimental septicemia in the mouse, A40926 A + B complex and its derivatives had activity proportional to their MIC for the test organism.

Animals↗
PubMed1986

Homologous telomeric sequences are present in different species of the genus Plasmodium.

The telomeric sequence cloned from Plasmodium berghei (see M. Ponzi et al. (1985) EMBO J. 4, 2991-2995) was tested for species specificity. A telomeric and a subtelomeric fragment of the cloned insert served as separate, labelled probes on pulsed field gradient electrophoretical patterns and on genomic digests from the rodent malarias Plasmodium yoelii, Plasmodium chabaudi and from the human malaria Plasmodium falciparum. Results indicate that the subtelomeric fragment, abundantly represented in two chromosomes of P. berghei, is not present in the other DNA tested, while the telomeric fragment is present in every chromosome-sized molecule in all the species tested. The telomeric location in the other genomes of the sequences homologous to the P. berghei telomeric probe is confirmed by experiments with Bal 31 exonuclease. In all cases, the TaqI site appears to delimit the common telomeric portion.

Animals↗
PubMed1984

In vitro activity of A-16686, a potential antiplaque agent.

A-16686, a new glycoproteide antibiotic from Actinoplanes sp., was evaluated as a potential antiplaque agent in comparison with chlorhexidine, benzalkonium chloride, and cetylpyridinium chloride. A-16686 had good activity against gram-positive organisms associated with dental plaque (various streptococci, Streptococcus mutans in particular, lactobacilli, Actinomyces viscosus, and Actinomyces naeslundii); most of the strains tested were clinical isolates. It was bactericidal for streptococci (MBC/MIC ratio of less than or equal to 8 for 92% of the strains) and for growing cells of S. mutans briefly exposed to antibiotic (99.9% killing within 5 min of contact with 200 micrograms of A-16686 per ml). It also inhibited the in vitro plaque formation by S. mutans and had good activity against preformed plaques. For most cases, its activity was comparable to those of chlorhexidine, benzalkonium chloride, and cetylpyridinium chloride. A-16686 appears to be a promising antiplaque agent because of the following attributes: narrow spectrum of activity, rapid bactericidal action, lack of selection of resistant mutants, absence of cross-resistance with clinically used antibiotics, nonabsorption by oral route, good tolerability by the oral mucosa (rats and dogs), and physical characteristics (white powder, soluble in water).

Anti-Bacterial Agents↗
PubMed1984

A-16686, a new antibiotic from Actinoplanes. II. Biological properties.

A-16686, a new glycoproteide antibiotic obtained from fermentation of an Actinoplanes strain, is active against Gram-positive aerobic and anaerobic bacteria; MIC values ranged from 0.016 to 2.0 micrograms/ml. A-16686 is bactericidal for growing cells of Staphylococcus aureus, S. epidermidis, Streptococcus faecalis, S. faecium, S. mutans, S. mitis and S. sanguis. There is no cross-resistance with clinically used antibiotics. A-16686, administered subcutaneously, is very effective in experimental S. pyogenes and S. pneumoniae septicemias in the mouse.

Ampicillin↗
PubMed1983

Statistical study of the angle formed by the lateral part of the mandibular condyle and the horizontal plane.

The angle between the LCA and frontal plane and the inclination of the lateral part of the mandibular condyle and the horizontal plane were measured in a sample of the skulls used in the study. Correlation between the two angles was found to be almost insignificant. Fifty-eight percent of the TMJs had an inclination of the lateral part of the condyle less than 15 degrees. The maximum value for this angle was found to be 45 degrees, and the minimum was -6 degrees.

Cephalometry↗
PubMed1983

Teichomycin: in-vitro and in-vivo evaluation in comparison with other antibiotics.

Teichomycin, a new glycopeptide antibiotic with a spectrum of activity similar to that of vancomycin, was highly active against staphylococci, streptococci and Gram-positive anaerobes (Propionibacterium acnes, Clostridium perfringens and Cl. difficile). Ninety per cent of the Staphylococcus aureus and streptococcal strains, including enterococci, were inhibited by 0.4 mg/l; 90% of Staph. epidermidis strains were susceptible to 1.6 mg/l. Vancomycin was less active than teichomycin against all clinical isolates tested. Multiply resistant strains, including methicillin-resistant Staph. aureus, were all susceptible to teichomycin and vancomycin. Teichomycin was highly bactericidal for growing cells of staphylococci and Streptococcus pyogenes and moderately bactericidal for Str. faecalis. In mice, teichomycin was well absorbed upon subcutaneous administration and had a half-life of 2.5 h. It was very effective in curing experimental mouse septicemias caused by Gram-positive bacteria (ED50 values less than 1 mg/kg).

Animals↗
PubMed1982

A clinical study of graphic registration of the condylar path inclination.

The angular values of the CSP registered from 390 patients and obtained by tracing a tangent to the graph with the GR were analyzed. The data subjected to statistical analysis gave a median angular value of the CSP equal to 33 degrees and showed a great median value dispersion. A low error index was obtained in tracing the tangent to the CSP tracing with the GR method. The angular values of the CSP were repeatable over time since the variations found were less than 5 degrees. Variations of the CSP greater than 5 degrees were noted after repeated registrations in patients with TMJ disturbances as well as in patients treated with complete dentures. These data show the necessity for an individual measurement of the CSP value, especially in patients who need extensive readjustments of the prosthesis.

Dental Occlusion↗
PubMed1982

Anatomic study of condylar position at maximum intercuspation.

An anatomic study of the mandibular condylar position was conducted on 40 dried skulls with intact dentitions. The distance between the condyle and the mandibular fossa in three different sections were measured anteriorly, superiorly, and posteriorly. The mandibular condylar was found to be in a slightly anterior position. The implications are discussed.

Cephalometry↗
PubMed1981

Antibacterial activity of DL 473, a new semisynthetic rifamycin derivative.

DL 473, a new semisynthetic rifamycin, was 2-10 times more active in vitro than rifampicin (RAMP) against several clinical isolates of Mycobacterium tuberculosis and only slightly less active than RAMP against Gram-positive and Gram-negative bacteria. It showed excellent therapeutic activity in mice in experimental infections caused by Staphylococcus aureus, Streptococcus pyogenes group A, Streptococcus pneumoniae and Klebsiella pneumoniae. In the experimental TB infection in the mouse DL 473 was clearly more active than isoniazide and RAMP, two of the most effective antitubercular drugs in current use. The LD50 in the mouse was significantly higher than that of RAMP and the half-life was about 5 times longer than that of RAMP.

Animals↗