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B Oliva

Publications and source records attributed to B Oliva.

72 records · Page 4Linked to original sources
PubMedDate not supplied

Multicentric study of seroprevalence of Borrelia burgdorferi and Anaplasma phagocytophila in high-risk groups in regions of central and southern Italy.

The aim of this study was to evaluate the seroprevalence of B. burgdorferi and A. phagocytophila in populations of workers from 4 Italian regions, known to be exposed to tick bites. A total of 712 serum samples collected were divided as follows: 387 samples were obtained from workers at risk for tick bites and 325 from individuals that were not considered to be at risk of ticks bites and served as the control group. Antibodies against B. burgdorferi were found in 29 (7.5%) of the 387 risk workers and in 4 (1.2%) of the 325 control group. Antibodies reactive with the HGE agent were found in 22 (5.7%) of the 387 risk workers and in 3 (0.9%) of the 325 control group. Antibodies to both B. burgdorferi and A. phagocytophila were found in 1.6% of the forestry workers confirming the possibility of coinfection or concurrent infection. The present finding show significant differences between seroprevalence of the risk workers and that of the people with no risk for tick exposure.

Anaplasma phagocytophilum↗
PubMedDate not supplied

Genetic variability among Blastoschizomyces capitatus isolates from different clinical sources.

Sixteen clinical isolates and nine ATCC reference strains of Blastoschizomyces capitatus were analysed genetically, examined for the cellobiose, arbutin and salicin assimilation and tested for the aspartyl-proteinase secretion. The restriction endonuclease analysis (REA) with HpaII and HinfI enzymes and the electrophoretic karyotype (EK) were investigated. Both the restriction enzymes revealed two groups (I, II) constituted by the same isolates: 17 isolates (68%) in group I and 8 (32%) in group II. The EK analysis revealed sixteen groups. These data prompts for a genetic variability of the isolates of Blastoschizomyces capitatus and their account in two distinct genetic groups as suggested by REA. This grouping was confirmed by examining the utilisation of cellobiose, arbutin and salicin. The tests for secretory aspartyl proteinase (Sap) were positive only for three isolates, suggesting a marginal role of this specific enzyme in pathogenesis for these isolates.

Arbutin↗
PubMedDate not supplied

Melaleuca alternifolia essential oil possesses potent anti-staphylococcal activity extended to strains resistant to antibiotics.

Melaleuca alternifolia Cheel essential oil (TTO) and its major component terpinen-4-ol were examined against a large number of clinical isolates of Staphylococcus aureus to establish their anti-staphylococcal activities. Classic and established procedures were used to study M.I.C., time-kill curves, synergism and mutational frequency. The anti-staphylococcal activity of terpinen-4-ol and TTO were superior to those of antibiotics belonging to the major families (all the tested drugs are for topical use or included in ointments, eye drops or used during surgery); terpinen 4-ol and TTO were active against strains resistant to mupirocin, fusidic acid, vancomycin, methicillin and linezolid. TTO and terpinen-4-ol were bactericidal as revealed by time-kill curves; the frequency of mutational frequency to TTO was < 2.9 x 10 9. The study demonstrates good anti-staphylococcal activity of TTO and terpinen-4-ol against a large number of S.aureus isolates and suggests the possible application of these agents for topical treatment of staphylococcal infections. This is the first extensive study on the anti-staphylococcal activity of TTO. The results suggest that this compound may have application as a topical agent for the control of superficial staphylococcal infections, including activity against organisms resistant to antibiotics which can be used, or are specific, for topical use.

Anti-Bacterial Agents↗
PubMedDate not supplied

Genotype and phenotype relationship in MLSb resistance in Streptococcus pyogenes and Streptococcus agalactiae isolated in central Italy.

The aim of this work is to study a correlation between phenotype and genotype in clinical isolates of erythromycin-resistant Streptococcus spp. Among the 25 erythromycin-resistant S. pyogenes, we detected six strains with iMLSB, nine with cMLSB and two with M phenotypes. Among 14 erythromycin-resistant S. agalactiae, we detected five strains with iMLSB, seven with cMLSB and none with an M phenotype. Moreover, 8 S. pyogenes and 2 S. agalactiae showed a phenotype not matching the known ones described in literature, defining an unknown phenotype. Upon examination, the genetic profiles, erm(A), erm(B) and mef(A), of the clinical isolates did not easily correlate with a specific phenotype. Our findings highlighted that the whole matter of phenotypic diversity in macrolide-resistant S. pyogenes and S. agalactiae strains and the correlation with their genetic profiles should be submitted to a more careful analysis of phenotypic and genotypic characterization.

Anti-Bacterial Agents↗
PubMedDate not supplied

In vitro chemosensitivity of chronic lymphocytic leukemia B-cells to multidrug regimen (CEOP) compounds using the MTT colorimetric assay.

BACKGROUND: Anthracycline-containing regimens have given controversial clinical results in CLL. Therefore, we explored the in vitro behavior of CLL B-cells after exposure to the compounds included in the most frequently used combination therapy regimen (CEOP). METHODS: A 4-day MTT colorimetric assay was used in vitro to test the effect of CEOP regimen drugs, either alone or in combination, on CLL B-cells. All drugs but mafosfamide, tested in place of cyclophosphamide, were used at concentrations corresponding to the in vivo dosage employed in the CEOP regimen. Chlorambucil was also studied since it represents the standard treatment for this disease. RESULTS: Epirubicin, prednisone and vincristine displayed a cytotoxic effect in 15, 13 and 4 out of 30 samples, respectively. Combinations of the same drugs showed a synergistic effect in 6 out of 13 assays. A cytotoxic effect of chlorambucil was detected in 2 out of 5 responders to the combination of CEOP regimen drugs, and in 3 out of 7 non responders. Mafosfamide induced a reduction in cell survival in 60-80% of the samples, depending on its concentration. CONCLUSIONS: The MTT assay is suitable for evaluating the in vitro chemosensitivity of CLL B-cells to multidrug regimen compounds. In the present study 40% of samples were resistant to CEOP regimen components in vitro. The possible role of MTT in predicting the clinical response to the CEOP regimen should still be established by prospective in vitro and in vivo studies.

Adult↗
PubMedDate not supplied

In vitro sensitivity of chronic lymphocytic leukemia B-cells to fludarabine, 2-chlorodeoxyadenosine and chlorambucil: correlation with clinico-hematological and immunophenotypic features.

BACKGROUND: Chlorambucil (CLB), 2-chlorodeoxyadenosine (2-CDA) and fludarabine (FAMP) are among the most widely used drugs in chronic lymphocytic leukemia (CLL). Therefore we evaluated in vitro sensitivity to these drugs and cross-resistance of purine analogs. In addition, we correlated the in vitro data with the main clinico-hematological variables and surface markers. PATIENTS AND METHODS: Eighty CLL samples obtained from 63 untreated and 17 treated CLL patients were tested in vitro with the MTT assay. Lethal dose (LD)50 values were calculated to determine sensitivity to CLB, 2-CDA and FAMP. RESULTS: Samples were clustered either for a one-log increase of LD50 values or for LD50 threshold values of 3 microM for FAMP, 0.3 microM for 2-CDA and 7 microM for CLB, which correspond to the therapeutically achievable plasmatic levels of these drugs. A higher number of samples sensitive to 2-CDA were identified by the first approach; with the second method the relative order of sensitivity was FAMP > 2-CDA > CLB. Concerning 2-CDA and FAMP cross-resistance, out of 61 samples resistant to 2-CDA, 29.5% were sensitive to FAMP. Conversely, 13.9% out of 43 samples resistant to FAMP were sensitive to 2-CDA. No correlation was found between the main clinico-hematological features and the LD50 values of each drug either considering the whole series or only the untreated cases. In vitro drug sensitivity was also evaluated during the steady-state of the disease and at disease progression in six untreated cases. We observed a mean increase in the LD50 values of about 13, 38 and 22 times for CLB, FAMP and 2-CDA, respectively. Among the treated cases, the LD50 values of both purine analogs and CLB correlated with bone marrow histology. CLL cells expressing CD14, CD11c, CD11b, and FMC7 were more resistant in vitro to purine analogs but not to CLB. CONCLUSIONS: This study suggests that i) the purine analogs exert a greater cytotoxic effect on CLL cells; ii) 2-CDA and FAMP are not cross-resistant in vitro in a percentage of CLL samples, iii) a possible change in LD50 values may be related to modification of the disease status, and iv) the expression of certain surface markers, which are CLL-unrestricted, identifies samples with higher in vitro resistance to purine analogs.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

The in vitro cytotoxic effect of mitoxantrone in combination with fludarabine or pentostatin in B-cell chronic lymphocytic leukemia.

BACKGROUND AND OBJECTIVE: Clinical studies indicate that combination chemotherapy with mitoxantrone (Mitox) and a purine analog can improve the response rate in indolent lymphoproliferative disorders. We explored the in vitro Mitox- fludarabine (FAMP)- and pentostatin (Pento)-induced cytotoxicity and their interactions in CLL. METHODS: The peripheral lymphocytes of 24 CLL patients were tested at different drug concentrations, with Mitox, FAMP or their combinations in 22 cases, and with Mitox, Pento or their combinations in 20 cases, 18 of which were the same from the FAMP group. The MTT assay was chosen for the drug-induced cell cytotoxicity and flow cytometry analysis of the DNA hypodiploid peak for the study of the apoptotic process. Drug interactions were calculated in the MTT assay according to both multiplicative and maximum models. RESULTS: According to the lethal dose (LD) 50 values, when the three drugs were tested alone, 11 out of 22 and 8 out of 20 samples were sensitive to Mitox in the FAMP and Pento groups, respectively; on the other hand, 2 out of 22 and 0 out of 20 samples appeared sensitive to FAMP or Pento alone, respectively. Analyzing the MTT assay data with the multiplicative and maximum model, the combinations of Mitox+FAMP and Mitox+Pento at different drug concentrations were synergistic in 28.2% and 39.3%, respectively. At leukemic cell survival < or = 50%, 11.7% and 11.1% of all combinations were synergistic in the Pento and FAMP group, respectively. The number of synergistic interactions at a therapeutically achievable plasma-drug concentration was an inverse function of the Mitox concentration. In the FAMP group, a direct correlation was found between the LD50 values of both FAMP and Mitox and the number of synergistic interactions, while the Pearson correlation coefficient was not significant in the Pento group. Finally, as measured by the DNA hypodiploid peak, Mitox (0.25 microgram/mL) plus Pento (0.16 microgram/mL) showed a significantly enhanced apoptosis in comparison to each single drug, while Mitox failed to demonstrate an additive effect with FAMP (1 microgram/ml). INTERPRETATION AND CONCLUSIONS: This experience demonstrates the extent of the in vitro synergism of Mitox with FAMP and Pento in inducing cell cytotoxicity; it also shows an adjunctive apoptotic effect for the Mitox-Pento association only.

Antibiotics, Antineoplastic↗