PubMed Health⌕ Search

Biomedical subjects

A Marrone

Publications and source records attributed to A Marrone.

25 records · Page 2Linked to original sources
PubMed1991

Activity of aminoglycosides against phagocytosed bacteria.

The intracellular activity of streptomycin, gentamicin, and netilmicin on Escherichia coli phagocytosed by murine peritoneal macrophages was studied using a sensitive and standardized method. Intracellular activity of streptomycin and gentamicin at therapeutic concentrations was seen after 1 h of incubation of antibiotics with macrophages containing phagocytosed bacteria, whilst for netilmicin a significant intracellular activity was observed only after 3 h exposure. The activity of these antibiotics against intraphagocytic bacteria was significantly lower than that observed against extracellular bacteria. Sub-inhibitory concentrations of streptomycin were active against intracellular E. coli. Streptomycin was also active for a phagocytosed streptomycin-resistant strain of E. coli, but this activity was eliminated when the O2-dependent killing mechanisms of macrophages were inhibited by sodium fluoride. The data demonstrate that aminoglycosides may exert a dose-dependent intraphagocytic activity against E. coli that correlates with the time of incubation of the antibiotics with infected macrophages. Streptomycin appears to be the most effective agent followed by gentamicin and the least active was netilmicin. In the case of streptomycin, the intraphagocytic activity seems to be due, at least in part, to the stimulation of O2-dependent cellular microbactericidal mechanisms.

Animals↗
PubMed1991

Prolonged treatment of children with chronic hepatitis B with recombinant alpha 2a-interferon: a controlled, randomized study.

A prospective study was conducted to evaluate the efficacy and tolerance of alpha-interferon in 20 children with biopsy-proven HBsAg/HBeAg/HBV-DNA-positive, anti-delta-negative chronic hepatitis. Patients were randomized to receive alpha 2a-interferon (INF), 3 MU im three times weekly for 12 months, or no treatment (10 patients per group). Five patients receiving IFN showed a marked decrease or negativization of HBV-DNA during treatment. At the end of the study (after 18 month), three patients lost HBV-DNA permanently, and two of them seroconverted to HBeAb 10 and 11 months after disappearance of HBV-DNA with normalization of aminotransferase values. In the control group, one patient had spontaneous clearance of HBV-DNA with conversion to HBeAb and normalization of aminotransferase levels. All treated patients had a febrile reaction in the first month of treatment. The dose of IFN had to be decreased in two patients and was discontinued for persistent intolerance in one of them. Patients who showed a decreased viral replication had higher initial biochemical and histological activity than nonresponders. The data suggest that IFN treatment may favorably influence the progression of chronic B hepatitis in children with a history of acute hepatitis and active chronic disease.

Adolescent↗
PubMed1990

Influence of subinhibitory concentrations of loracarbef (LY 163892) and daptomycin (LY 146032) on bacterial phagocytosis, killing and serum sensitivity.

The aim of this study was to evaluate whether pre-exposure of bacteria to a subinhibitory concentration (sub-MIC) of loracarbef (LY 163892) or daptomycin (LY 146032) could modify bacterial susceptibility to serum bactericidal activity and to phagocytosis and killing by murine peritoneal macrophages and by human polymorphonuclear leucocytes. Escherichia coli, Haemophilus influenzae type b and Staphylococcus aureus grown in the presence of one quarter the MIC of loracarbef, and S. aureus exposed to one quarter the MIC of daptomycin were phagocytosed and killed in numbers significantly higher than non-exposed bacteria. Pre-exposure to loracarbef resulted in increased susceptibility of E. coli and H. influenzae type b to the bactericidal activity of antiserum, but exposure to loracarbef or daptomycin did not modify serum sensitivity of S. aureus. Loracarbef treatment and antiserum enhanced phagocytosis and killing of E. coli and H. influenzae type b to a greater extent than either antibiotic treatment or antiserum alone. These data indicate that loracarbef and daptomycin at sub-MIC enhance the susceptibility of bacterial pathogens to cellular and host defence mechanisms.

Bacteria↗
PubMed1990

[The ultrastructural aspects of the synovial intima and subintima in arthrosis].

Synovial membrane removed surgically from patients during developing degenerative joint disease were studied under a scanning and transmission microscope. The results show that the synovial membrane is folding into villi of average dimensions (microvilli and macrovilli) which project into articular cavity. In regard to the villi, the morphology is locally changeable, with the atrophic-sclerotic areas alternated with hyperplastic areas, but topographically well defined. In the last ones, structural modifications of the intima layer, are characterized by hypertrophy of B synoviocytes, which are constituent and predominant cells in comparison with other cell-types. In the subintima around ectatic vessels, the linfomonocitary inflammatory infiltrations may be found. These alterations are the results of active biological process and because of this synovial membrane is of big importance in developing of osteoarthritis.

Aged↗
PubMedDate not supplied

Post occlusion ischemia in the territory of the internal carotid artery: role of the ophtalmic collateral circulation in relation to the status of the bifurcation.

Recent studies of the literature indicate that arteriosclerotic lesions located in the remnants of bifurcation and proximally to an occluded internal carotid artery can represent sites for the origin of emboli. Through the collateral circulation, these emboli can reach the homolateral cerebral territories producing further ischemic events. Two groups of patient, with angiographically proven internal carotid artery occlusion, one with, and another without irregular arteriosclerotic lesions (IAL) in the stump and/or external carotid artery, were followed up in order to determine the frequency of delayed post-occlusion ischemic events in each group. Ipsilateral events occurred more frequently when there was a stump associated with IAL in the remnants of bifurcation and signs of ophtalmic collateral circulation. This association may have prognostic value and should be considered before performing bypass procedures.

Adult↗
PubMedDate not supplied

[Giant bladder calculus. Report of a clinical case].

The authors describe a case of giant vesical calculus in an 89 year old patient. The diagnosis, as in the other cases reported in the international literature, was made after a series of laboratory and instrumental exams, for groups reported by the patient in the lower abdomen. Operated for the removal of the vesical calculus, he was considered healed after a fortnight. The vesical calculus has a mixed composition and it weighs about 380 grams. The revision of the literature shows the various chemical composition of the vesical calculus that does not permit to identify a common aetiology. It is not possible to demonstrate if the formation of this kind of calculus is primary (in the urinary bladder) or if it is proper of the high urinary tract or mixed. The most recurrent causes being various and different confirm the mixed aetiopathologic theory. The diagnosis, often casual, is made thanks to the most common diagnostic exams; as it is difficult to make a complete cystoscopic control because the bladder is almost completely occupied by the lithiasic formation. The surgical therapy consists of a epicystotomy with a following removal of the calculus. In literature, moreover, cases treated with extra-body lithotripsy are not reported, on the contrary ot happens daily for the lithiasis of the high urinary tract.

Aged↗