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Biomedical subjects

M Berti

Publications and source records attributed to M Berti.

At least 109 records · Page 6Linked to original sources
PubMed1986

Activity of teicoplanin in localized experimental infections in rats.

We tested the ability of teicoplanin alone and in combination with rifampicin or gentamicin to cure experimental endocarditis and granuloma pouch infections in rats caused by Streptococcus faecalis, Str. sanguis, methicillin-sensitive and -resistant Staphylococcus aureus. Vancomycin and ampicillin were also tested. Teicoplanin was more active than vancomycin and ampicillin. Combinations of teicoplanin with rifampicin or gentamicin were significantly more effective than single drug therapy. These results suggest that teicoplanin could be an interesting alternative to vancomycin in the treatment of serious streptococcal and staphylococcal infections in man.

Animals↗
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↗
PubMed1984

Teicoplanin, antibiotics from Actinoplanes teichomyceticus nov. sp. VI. Chemical degradation: physico-chemical and biological properties of acid hydrolysis products.

Teicoplanin is an antibiotic complex consisting of five closely related factors, T-A2-1, 2, 3, 4 and 5 and a more polar factor, T-A3-1. By controlled acid hydrolysis the complex is transformed into pseudoaglycones and finally into a single aglycone with consecutive removal of three sugar units. Quantitative determination of sugars obtained by degradative reactions and NMR/LC-MS studies on suitable derivatives confirmed that all the components carry one N-acyl-D-glucosamine and that at least two of them are characterized by N-decanoyl and N-undecanoyl chains on the D-glucosamine unit. The hydrolysis products still possess in vitro and in vivo activity.

Animals↗
PubMed1984

7-(D,L-alpha-fluoro-2-thienylacetamido)cephalosporanic acid (L 14655), a new semisynthetic cephalosporin. Synthesis and preliminary biological evaluation.

We describe the synthesis and some preliminary antimicrobial and enzymatic properties of 7-(D,L-alpha-fluoro-2-thienylacetamido)cephalosporanic acid (L 14655), a fluorinated derivative of cephalothin. L 14655 had antimicrobial activity similar to that of cephalothin. Cell-free studies demonstrated that L 14655 was very stable to hydrolysis by type Ia beta-lactamase (325 times more than cephalothin) but not to TEM enzyme. In addition, L 14655 was 480 times more active than cephalothin in preventing the hydrolysis of nitrocephin by type Ia enzyme. Preliminary studies in intact beta-lactamase-producing cells did not however produce evidence of enhanced activity of L 14655 relative to cephalothin.

Anti-Bacterial Agents↗
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 new model of experimental Bacteroides fragilis infection in mice and rats.

We describe a method, based on Selye's granuloma pouch, for establishing reproducible Bacteroides fragilis infections in both mice and rats starting from rather low inocula. The infected pouches resemble abscesses and phlegmons. This model is promising for studies of antibiotic therapy in that both bacterial kinetics and antibiotic levels can be followed in the exudates.

Animals↗
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↗
PubMed1980

A non steroidal anti-inflammatory drug that stimulates prostaglandin release.

Diacetylrhein (DAR) is a new anti-inflammatory and anti-osteoarthritic drug. Studies with isolated lung preparation showed that DAR does not exert its action by inhibiting the arachidonic acid metabolism. Furthermore, the in vivo experiments showed that DAR, contrary to most anti-inflammatory drugs, induced an increase of prostaglandin-like substances in the rat exudates. The above results are substantiated by experimental evidence that in the rat this compound displays a dose-dependent protecting activity against indomethacin-induced gastric damage.

Animals↗
PubMed1979

Kinetics of a rifampicin-trimethoprim combination.

Two different regimens of a rifampicin-trimethoprim combination were studied in two groups of healthy volunteers. Each regimen was administered for seven consecutive days. In the first, the treatment consisted of 300 mg of rifampicin and 80 mg of trimethoprim administered t.i.d. In the second 450 mg of rifampicin and 120 mg of trimethoprim were administered b.i.d. Data on serum levels and urinary excretion are discussed.

Adult↗
PubMed1979

[Synthesis and biological activity of 7-(2-nitroimidazoles and 7-(2-aminoimidazole) methyleneamino cephalosporin and their derivatives].

The synthesis of 7-[[(1-methyl-2-nitro-1H-imidazol-5-yl)methylene]amino] and 7-[[(2-amino-1-methyl-1H-imidazol-5-yl)methyle-ne]amino]cephalosporanic acids and of some derivatives is described. Their physico-chemical characteristics are reported. The compounds show no appreciable antibacterial activity in vitro. They show no synergy with cephaloridine against Enterobacter cloacae 214 (producer of class I beta-lactamase) and therefore have no anti-beta-lactamase activity.

Cephalosporins↗
PubMed1978

Synthesis and biological activities of some cephalosporin derivatives with carbonylamino or acetylamino [(nitro or amino) imidazole] substituents in position 7.

The synthesis and the physicochemical properties of some cephalosporin derivatives with a carbonylamino- or acetylaminoimidazole moiety in position 7 are described. The effects on biological activity of the presence of some groups (methyl or ethyl, 2-nitro or 5-nitro, 2-amino) on the imidazole nucleus are examined. Selected heterocyclicthiomethyl substituents were also introduced in the 3 position of the cephalosporin nucleus. The in vitro antimicrobial activities of the compounds and their effectiveness in protecting against bacterial (S. aureus) infections in mice were evaluated. Two of the compounds (V b) and (V d) are as active as cephalexin and more active than cephalothin when administered subcutaneously, while they appear to be less effective when administered orally.

Animals↗
PubMed1978

Teichomycins, new antibiotics from Actinoplanes teichomyceticus Nov. Sp. I. Description of the producer strain, fermentation studies and biological properties.

A soil isolate of Actinoplanes that produces the chemically unrelated new antibiotics teichomycins A1 and A2 has been proposed as a new species named Actinoplanes teichomyceticus nov. sp. (ATCC 31121). Studies of medium and fermentation conditions indicated that the highest antibiotic titers, ca 900 u/ml, are obtained in a medium containing 1% (w/v) glucose, 1% cotton seed meal, 1% malt extract, and 0.4% yeast extract. Both teichomycin A1 and teichomycin A2 are highly active against gram-positive bacteria. Teichomycin A1 shows some activity against gram-negative bacteria. Both antibiotics cured mice experimentally infected with sensitive bacteria and showed low acute toxicity. Of the two antibiotics teichomycin A2 is the more active.

Actinomycetales↗