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Biomedical subjects

G Nicoletti

Publications and source records attributed to G Nicoletti.

At least 217 records · Page 12Linked to original sources
PubMed1987

The sensitivity of gram-negative and gram-positive bacteria to ofloxacin.

The in vitro antimicrobial activity of ofloxacin, a new fluorinated quinolone, was evaluated against 165 Gram-negative rods, both fermentative and non-fermentative, and against 57 Gram-positive strains (coagulase-positive and -negative staphylococci both methicillin-resistant and -susceptible, and Streptococcus faecalis). Minimal inhibitory concentrations were determined by using the macrodilution test and the activity was compared with nalidixic acid, norfloxacin, ampicillin, piperacillin, ceftazidime and gentamicin for Gram-negative rods; norfloxacin and gentamicin for Staphylococcus strains; and norfloxacin, ampicillin, piperacillin and gentamicin for enterococci. Ofloxacin inhibited all fermentative Gram-negative bacteria tested, in a range of 0.05-3.12 mcg/ml, and had good antimicrobial activity against non-fermentative Gram-negative strains: it inhibited 90% of Acinetobacter and 80% of P. aeruginosa tested, at 3.12 mcg/ml. Ofloxacin had a high antimicrobial activity against Staphylococcus and Enterococcus strains tested.

Anti-Bacterial Agents↗
PubMed1987

Anti-mycoplasmal activity of a new macrolide: miocamycin.

The object of this study was the evaluation of the activity of miocamycin and other macrolides (erythromycin and josamycin) against 61 Ureaplasma urealyticum, 1 Acholeplasma laidlawii and 21 aerobe mycoplasmas (M. pneumoniae, M. hominis, M. gallisepticum, M. mycoides) and anaerobe mycoplasmas (M. morale and M. salivarium) both clinically isolated and standard reference strains. The minimum inhibitory concentrations (MIC) values for miocamycin ranged between 0.00625 mg/l and 0.4 mg/l (ureaplasmas) and between 0.001 mg/l and 0.0625 mg/l (mycoplasmas, except M. hominis with 0.025 mg/l to 0.25 mg/l). For erythromycin, the MIC values ranged between 0.19 mg/l up to 500 mg/l (ureaplasmas) and between 0.001 mg/l to 0.0625 mg/l (mycoplasmas, except M. hominis with 100 mg/l to 1000 mg/l). MIC values for josamycin ranged between 0.03125 mg/l and 0.5 mg/l (M. pneumoniae only). The sub-MIC treatment (carried out on human pathogenic mycoplasmas only) evidenced growth curve modifications and a decrease of the O2 uptake directly correlated to the drug concentrations.

Acholeplasma↗
PubMed1986

RMZ: a new cell line from a human alveolar rhabdomyosarcoma. In vitro expression of embryonic myosin.

The RMZ cell line was established from a bone marrow metastasis of a human alveolar rhabdomyosarcoma. Since the beginning of the in vitro culture, RMZ cells showed differentiation-related morphological heterogeneity: actively proliferating polygonal or spindle-shaped cells were observed along with a few multinucleated myotube-like structures and giant cells, frequently multinucleated. All these cell types were still present after over 40 passages. A set of clonal derivatives has been obtained from the second in vitro subculture. All the clones showed the same morphological heterogeneity of the parental cells, but differed from one another in the degree of differentiation. Multinucleated myotube-like structures were strongly stained by anti-desmin antibody; most mononuclear cells were weakly stained. About 80% of RMZ and cloned cells were scored as desmin-positive in cytocentrifuged preparations. The expression of embryonic myosin heavy chain, specifically recognized by the monoclonal antibody BF-G6, was found in RMZ cell line and was localised in the myotube-like structures. Only a few giant cells and rare mononucleated polygonal cells were stained. The average proportion of BF-G6 positive cells in cytocentrifuged preparations was of about 6% of the total RMZ cells. In the two RMZ clones studied, the expression of embryonic myosin was correlated to the proportion of myotube-like structures: a BF-G6 positivity of 35% was found in the most differentiated one.

Cell Count↗
PubMed1986

Microbiological basis for the use of fosfomycin trometamol as single-dose therapy for simple cystitis.

Fosfomycin trometamol (FOT), a new soluble salt of fosfomycin, was developed especially for single-dose treatment in uncomplicated urinary tract infections. In this study, the minimum inhibitory concentrations (MICs) of FOT were measured both in nutrient broth and human urine and compared with calcium fosfomycin, pipemidic acid and cotrimoxazole. A total of 300 bacterial strains of different species from recent urinary infections were studied. Staphylococcus aureus showed the lowest MIC (0.38 micrograms/ml) and Pseudomonas spp. the highest (50 micrograms/ml) with fosfomycin salts in nutrient broth. The MIC of fosfomycin resulted in being higher than those for pipemidic acid and cotrimoxazole against Escherichia coli and Proteus rettgeri and lower for all the other species considered. The MIC values increased about ten times when urine was used as medium. No differences were observed between the two fosfomycin salts. The fosfomycin concentrations of 137-1500 micrograms/ml, easily obtained in urine of healthy adult subjects after a single dose of FOT (3g of fosfomycin), were able to kill all the strains, with the exception of Streptococcus faecalis. The bacterial adhesion of a resistant microorganism (P. aeruginosa) to the cells of the urinary tract, showed a 50% reduction after FOT treatment.

Bacteria↗
PubMed1986

Clones with different metastatic capacity and variant selection during metastasis: a problematic relationship.

Cells from TS/A, a metastasizing line derived from a spontaneous BALB/c mouse mammary adenocarcinoma, were injected either sc or iv in syngeneic mice, and the resulting lung metastases or lung colonies were briefly cultured in vitro and reinjected in mice by the same route; this procedure was repeated 10 times. All the variants obtained did not show a metastatic capacity higher than the parental cell line. Moreover, they gave a number of metastases significantly lower than that produced by high metastatic clones selected in vitro from TS/A. The number of lung colonies obtained with intravenously selected (COL) variants was significantly higher than that obtained with subcutaneously selected (META) variants, TS/A, or in vitro-selected clones; this was already observable after the first cycle of selection. Both COL and META variants did not show the in vitro growth properties of the in vitro-selected high metastatic clones. In conclusion, both intravenous and subcutaneous selection procedures did not lead to an enrichment in high metastatic populations, even if such populations were present in the parental line and had been cloned in vitro; only the intravenous procedure selected high-colonizing variants.

Animals↗
PubMed1986

In vitro activity of imipenem towards gram-negative bacilli.

The authors studied the in vitro antimicrobial activity of imipenem towards 355 gram-negative bacterial strains, taking into particular consideration unusual or dangerous species. The study was carried out on a comparative basis with piperacillin, cefotaxime, ceftazidime and gentamicin. Ninety percent of the fermentative gram-negative strains were inhibited at concentrations less than or equal to 2 mg/l. Imipenem inhibited 100% of strains of Alcaligenes faecalis, Alcaligenes denitrificans, Flavobacterium odoratum, Acinetobacter lwoffii, Acinetobacter anitratum, Pseudomonas fluorescens, Pseudomonas stutzeri and 90% of strains of Pseudomonas aeruginosa and Pseudomonas putida. The excellent bactericidal activity of imipenem was indicated by its minimum bactericidal concentrations equal to or slightly greater than its minimum inhibitory concentrations (MIC). As far as the other parameters were concerned (influence of the dimensions of inoculum and culture medium on MICs), imipenem confirmed its excellent in vitro microbiologic characteristics.

Anti-Bacterial Agents↗
PubMed1986

New trends in the chemotherapy of staphylococcal infections.

The authors evaluated the susceptibility of some antibiotics against several Staphylococci subdivided in lyogroups and different resistance patterns: methicillin-susceptible/penicillin-susceptible (MS/PS), methicillin-susceptible/penicillin-resistant (MS/PR), methicillin-resistant/penicillin-resistant (MR/PR) and methicillin-resistant/penicillin-susceptible (MR/PS). The antimicrobial agents used were: methicillin, penicillin, rifampin, tetracycline, lincomycin, erythromycin, gentamicin and netilmicin. Netilmicin showed better activity against all Staphylococcus strains tested, particularly against coagulase-negative.

Anti-Bacterial Agents↗
PubMed1986

Studies on lincosamide antibiotic resistance in methicillin-susceptible and -resistant staphylococci.

Lincomycin and clindamycin are still effective against anaerobic bacteria, and their antibacterial activity has also been indicated against gram-positive aerobic cocci, chiefly Staphylococcus aureus. The present emergency due to epidemiological circulation of Staphylococci, especially coagulase-negative, methicillin-resistant, and the question of the current validity of the lincosamides, induced us to study the activity of lincomycin and clindamycin against staphylococci belonging to different lyogroups in comparison to erythromycin. Clindamycin showed good antibacterial activity while methicillan-resistant strains showed an increase in resistance to erythromycin and lincomycin.

Anti-Bacterial Agents↗
PubMed1986

Epidemiology of resistance to netilmicin and other aminoglycosides.

The authors carried out a study to evaluate the epidemiology and resistance of netilmicin, gentamicin, tobramycin and amikacin during the 1984-1985 period. Clinical specimens of different origin, drawn both from hospitalized and outpatients were used in the study. The strains were tested for their sensitivity to aminoglycosides. In particular the degree of resistance in both fermentative and non-fermentative gram-negative strains was determined. As previously pointed out in other works, netilmicin showed good antimicrobial activity in respect to other aminoglycosides.

Amikacin↗
PubMed1985

Colony-stimulating activity from the new metastatic TS/A cell line and its high- and low-metastatic clonal derivatives.

We investigated the presence of colony-stimulating factor (CSF) in supernatants obtained from TS/A, a new metastatic murine cell line, and from its high-and low-metastatic clonal derivatives (E and F clones, respectively). TS/A cells produced a CSF in vitro that induced proliferation and differentiation of murine monocytic and granulocytic progenitors in agar cultures. In TS/A-bearing mice remarkable splenomegaly, blood granulocytosis and thymus depletion were observed along with a stimulatory activity in serum and a strong proliferative activity both in spleen and in bone marrow populations. Conditioned media from E clones showed an in vitro colony-stimulating activity greater than those of F clones. Mice injected subcutaneously with cells of all clones studied showed granulocytosis, splenomegaly and thymus depletion, although to varying degrees. However, no direct correlation between granulocytosis-splenomegaly and the number of spontaneous lung metastases was observed.

Animals↗
PubMed1985

[ABAC, a closed system: problems and solutions, currency and perspectives].

The ABAC System, as it is currently configured, uses pre-determined panels of antibiotics. This form of presentation is a limit for the use of the large number of new molecules, mainly active on Gram-negative bacteria. Therefore, the introduction of a new disposable, called "Gram-negative bacteria--new molecules" is suggested. Such a device will contain those additional and more widely tested antibiotics. According to recent studies concerning the pathology of Gram-positive organisms and the chemotherapeutic treatment for such pathology, changes in the disposable formulations for staphylococci and streptococci are proposed.

Anti-Bacterial Agents↗
PubMed1985

In vivo reexpression of H-2 antigens in B16 melanoma cells.

We have previously shown that B16-A (H-2b) murine melanoma cells, when cultured in vitro for more than ten passages, have an undetectable or reduced expression of H-2Kb and Db antigens, respectively. We have now studied the possibility to restore H-2 expression (measured by quantitative antisera absorption) in B16-A cells either by a limited (30 days) period of in vivo growth or by treatment with immune interferon. In vivo transplants in allogeneic H-2k or H-2d mice and in H-2-compatible but Mls and multiple non-H-2 loci incompatible mice restored the normal expression of Kb and Db antigens. Cells obtained from tumors grown in syngeneic or in minor histocompatibility antigens-allogeneic mice showed only a weak increase in Db antigens. Such induction of H-2 expression appears to be mediated by the host's immune system, since (1) cells obtained from tumors grown in allogeneic BALB/c nude mice expressed much lower levels of H-2 antigens than those from tumors grown in normal BALB/c mice, and (2) it was possible to induce H-2 expression by growing B16 cells in syngeneic C57Bl/6 mice previously allostimulated with unrelated BALB/c tumor. In vitro treatment with immune interferon restored the expression of both Kb and Db antigens. We hypothesize that H-2 reexpression on B16 cells grown in allogeneic hosts could take place via the nonspecific components of the immune response, such as immune interferon.

Animals↗