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Biomedical subjects

A Mazzoni

Publications and source records attributed to A Mazzoni.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Association between hepatitis C virus and mixed cryoglobulinemia [see comment].

The prevalence of hepatitis C virus (HCV) RNA and of antibodies to HCV in an unselected series of 42 mixed cryoglobulinemia patients was investigated in this study. HCV RNA was detected by the polymerase chain reaction technique, and HCV antibodies by two enzyme-linked immunosorbent assays (Chiron ELISA HCV, Second Generation, Emeryville CA, USA; Wellcome Diagnostic, England). HCV RNA was found in 86% of the mixed cryoglobulinemia patients. Using either the Chiron ELISA or the Wellcome ELISA, HCV antibodies were present in 90% of the same samples; anti-HCVAb seropositivity was confirmed in all cases by immunoblot assay (Chiron RIBA HCV, Second Generation Assay). A striking correlation between HCV RNA and anti-HCV antibody seropositivities was recorded. HCV RNA in mixed cryoglobulinemia patients was not correlated with the presence or absence of biopsy-proven liver involvement. These results suggest that the association between HCV and mixed cryoglobulinemia is not fortuitous, and therefore that HCV may have an etiopathogenetic role in this disorder.

Adult↗
PubMedDate not supplied

Membrane gangliosides and immuno-mediated cytolysis in drug sensitive and treatment-induced multidrug resistant human ovarian cancer cells.

The pattern of cytoplasmic membrane gangliosides and two cellular features which have been reported to be related to the expression of different membrane gangliosides, namely adhesion to solid substrates and susceptibility to the lytic activity of immune effector cells, have been investigated in drug sensitive A2780 human ovarian cancer cells and in two treatment-induced multidrug resistant sublines (A2780-DX1 and A2780-DX3). The total membrane gangliosides content of A2780 sensitive cells was comparable to that of the two multidrug resistant (MDR) sublines, but the acquisition of the MDR phenotype was characterized by an increased expression of the polysialylated gangliosides (particularly the disialoganglioside GDIa) and decreased expression of the monosialoganglioside GM2. The kinetics of cellular adhesion (both to plastic culture dishes and to extracellular matrix coated dishes) were similar in the three cell lines, indicating that the gangliosides profile seems not to be relevant for cell adhesivity to the above mentioned substrates. When human peripheral blood lymphocytes in toto (PBL) and two lymphokine activated (LAK) T cell subpopulations (CD3+4-8- and CD3-16+) were used as effector cells against A2780 (sensitive) and A2780-DX3 (highly resistant) cells, cytolysis of target cells was more efficient against the A2780-DX3 subline, suggesting a possible role of the ganglioside GD1a as a target structure for LAK immunotherapy.

Antineoplastic Agents↗
PubMedDate not supplied

Effect of the tiapamil analog RO11-2933 on cellular sensitivity to antitumor drugs in sensitive and multidrug resistant human ovarian cancer cells.

The ability of the Tiapamil analog N-(3,4 Dimethoxyphenyl)-N-methyl-2-(naphthyl)-m-dithiane-2-propylamine hydrocloride (RO11-2933) to influence the cytotoxic activity of Doxorubicin (DX) and seven other antitumor agents was evaluated in sensitive and treatment-induced multidrug resistant human ovarian cancer cells. In vitro treatment of A2780 sensitive cells with 1 microM RO11-2933 for 72hr potentiated by less than 3-fold the cytotoxic effects of each antitumor drug tested, with the exception of Cisplatin and Fluorouracil, which were potentiated by 7.2- and 5.0-fold, respectively. In A2780-DX3 resistant cells, RO11-2933 increased by a mean of 50-fold the cytotoxic effects of the anthracyclines and the Vinka alkaloids analyzed. A potentiation of Cisplatin activity was also observed (6.5-fold), whereas the Tiapamil analog did not significantly modify the antiproliferative activity of Bleomycin, Fluorouracil or Ara-C. Analysis of DX uptake and retention showed that in resistant cells RO11-2933 restored the intracellular DX content to levels comparable to those of sensitive A2780 cells, suggesting that the cytoplasmic membrane might represent a possible site of action of this compound. The results obtained indicate that RO11-2933 might represent an effective agent in combination with several anticancer drugs for the treatment of drug resistant ovarian carcinomas.

Antineoplastic Agents↗
PubMedDate not supplied

Enhancement of adriamycin-induced cytotoxicity by increasing retention and inhibition of DNA repair in DOX-resistant P388 cell lines with new calcium channel blocker, DMDP.

The effect of DMDP, N-(3,4-dimethoxyphenethyl)-N-methyl-2-(2-naphthyl)-m-dithiane-2-propylam ine hydrochloride, on DOX-induced cytotoxicity, drug uptake, DNA damage and repair was investigated in adriamycin sensitive and resistant P388 cell lines. In vitro, the DOX-resistant P388 cells used are about 300-fold more resistant than the sensitive cells. Resistant cells were characterized by lower DOX accumulation, rapid drug efflux, significant decrease of DNA single and double strand breaks and rapid repair of the induced single strand breaks. DMDP, a calcium channel blocker, is an effective modulator of DOX resistance in P388 cells. This modulation was found to be highly dependent of the concentration of the modulators, optimal at the maximally moncytotoxic concentrations of 1-4 microM, and the duration of exposure to the modulator, optimal under conditions of continuous exposure to the modulator. Under the optimal conditions in the presence of the modulator, DMDP, both intracellular concentration and retention of DOX were restored in the resistant P388 cells to the value comparable to those found in DOX sensitive P388 cells. Even though DOX accumulation and retention were at a comparable level in both the sensitive and resistant cells in the presence of DMDP, the amount of DNA single strand breaks achieved in the resistant cells was only about 30% of the amount of damage observed in the sensitive cells. The data indicate that if P388/R cells were only exposed to DOX for about 2 h, the induced DNA single strand breaks were repaired rapidly within 8 h thereafter, while no significant repair was seen in the resistant cells exposed to DOX in combination with DMDP. In contrast, the repair of the extensive DNA single strand breaks induced by DOX in P388/S cells was not effected by DMDP. These data clearly demonstrated that resistance to DOX in P388 cells are multifactorial. Restoration of intracellular accumulation and retention of DOX by DMDP in the resistant cells are although necessary but not sufficient for complete restoration of the sensitivity of the highly resistant cells.

Alkaloids↗
PubMedDate not supplied

[Surgery of the base of the skull].

This is a review of the current status of the surgery of the skull base with special reference to the otolaryngological districts. The main topics are as follow: classification of pathology review of the clinical and surgical anatomy clinical and neuroradiological diagnosis surgical management of the pathology in the occipito-temporal area and in the rhinobase principles of management and operative approaches to the skull base in Neurosurgery principles of management and operative approaches to the skull base in Maxillo-Facial Surgery.

Humans↗
PubMedDate not supplied

Plasma retinol levels and side effects following high-dose retinyl acetate in breast cancer patients.

Plasma retinol levels and toxicity were evaluated in thirteen metastatic breast cancer patients treated orally with high-dose (300,000 I.U./day) retinyl acetate in combination with oral tamoxifen. Following the first dose of the drug, there was a drop of plasma retinol concentrations followed by a recovery to the pre-treatment levels and by a further increase to reach a plateau six to eight hours after drug administration. During the first two months of treatment cumulative increase of plasma retinol was seen, and long-term systemic concentrations in the +50-60% range level were maintained by the treatment. The toxicity observed was acceptable and included gastrointestinal symptoms, skin toxicity and headache. These toxicities could be related to the long-term increase of retinol systemic concentrations. We concluded that the daily dose of 300,000 I.U. retinyl acetate can be administered to cancer patients over a period of several months, is well tolerated and yields a substantial increase of systemic retinol.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

[Antifungal prophylaxis: up-date and prospectives].

Author reviews the now available strategies for the prophylaxis of primary and opportunistic mycoses. Chemoprophylaxis of opportunistic mycoses that are the most frequently observed fungal infections in Italy, gives satisfactory protection in endogenous fungal infections. On the contrary, fungal exogenous infections are not easily treated. In fact, systematically acting drugs which are also easy to use, are still lacking. Strict reverse isolation seems to achieve good results in these infections.

Administration, Oral↗