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Biomedical subjects

L Orlando

Publications and source records attributed to L Orlando.

52 records · Page 3Linked to original sources
PubMed1997

Cytokine-induced expression of CD1b molecules by peripheral blood monocytes: influence of 3'-azido-3'-deoxythymidine.

CD1b is a nonpolymorphic, MHC-like molecule, capable of presenting non-peptide antigens (Ags) to CD3+, CD4-, CD8-, alphabeta or gammadelta T lymphocytes. Previous studies have shown that CD1b can be induced in monocytes/macrophages by GM-CSF+IL-4, and can restrict their presentation of Mycobacterium tuberculosis antigen (Ag) to Ag-specific T cells. Since a number of HIV-positive subjects undergo mycobacterial infections, preliminary studies have been performed to explore whether anti-HIV chemotherapy would influence cytokine-induced CD1b expression in peripheral blood monocytes. The results obtained by treating monocytes with GM-CSF+IL-4, in presence or absence of 3'-azido-3'-deoxythymidine (AZT) showed that: (a) the majority of adherent mononuclear cells (AMNC) collected from peripheral blood of healthy donors, express CD1b molecule on the cell membrane, upon treatment with GM-CSF+IL-4; (b) CD1b appearance is mainly due to the de novo induction of CD1b gene expression (as confirmed by Northern blot analysis), rather than to migration of the molecule from the cytoplasm to the plasma membrane (as suggested by Western blot analysis); (c) AZT does not alter the percentage of CD1b+ AMNC treated with the cytokines; (d) however, AZT inhibits cytokine-induced proliferation of AMNC, thus reducing the overall Ag-presenting potential of the host. Our results suggest that the anti-proliferative effect of AZT could depress anti-mycobacteria immunity in AZT-treated subjects, which may have important implication for the clinical outcome of patients harbouring inadequately treated mycobacterial infections.

Anti-HIV Agents↗
PubMed1997

Inhibition of O6-alkylguanine DNA-alkyltransferase or poly(ADP-ribose) polymerase increases susceptibility of leukemic cells to apoptosis induced by temozolomide.

High levels of expression of the DNA repair enzyme O6-alkylguanine DNA-alkyltransferase (OGAT) (EC 2.1.1.63) account for tumor cell resistance to methylating agents. Previous studies suggested that methylating triazenes might have a potential role for the treatment of acute leukemias with low levels of OGAT. In the current study, we transduced the human OGAT cDNA in OGAT-deficient leukemia cell clones. OGAT-transduced cells were more resistant than their OGAT-deficient counterparts to apoptosis triggered by the methylating triazene temozolomide (TZM), as indicated by the results of flow cytometry, terminal deoxynucleotidyl transferase assay, and analysis of DNA fragmentation. Depletion of OGAT activity by O6-benzylguanine increased leukemia cell sensitivity to TZM-mediated apoptosis. Moreover, combined treatment of cells with TZM and benzamide, an inhibitor of the poly(ADP-ribose) polymerase (EC 2.4.2.30), increased the apoptosis induced by the methylating agent. These results demonstrate for the first time that methyl adducts at the O6 position of guanine, which are specifically removed by OGAT, are the principal DNA lesions responsible for the induction of apoptosis on treatment of leukemic cells with the methylating triazene TZM. This study also supports the possible use of TZM for the treatment of acute leukemias and suggests new strategies to increase the susceptibility of tumor cells to methylating triazenes in the clinic.

Antineoplastic Agents, Alkylating↗
PubMed1997

Dacarbazine-induced immunogenicity of a murine leukemia is attenuated in cells transfected with mutated K-ras gene.

Strong immunogenicity is induced by antitumor triazene compounds in tumor cells through a mutagenic mechanism. A highly immunogenic < > clone, isolated from a dacarbazine-treated L5178Y leukemia of DBA/2 mice, was transfected with K-ras mutated at codon 12 (i.e. ras(m12)). This transfected clone presents at least 2 mutations, one concerning K-ras gene, and the other affecting an unrelated gene, responsible for the generation of a highly immunogenic, MHC class I restricted non-self peptide. The results indicate that cells of < > clone transfected with ras(m12) were less immunogenic than cells of the same origin transfected with the vector alone. Moreover, ras(m12)-transfected cells showed lower levels of H-2K(d) gene expression with respect to those detectable in control cells. In addition, in vivo and in vitro sensitization against < > clone carrying mutated ras did not result in a strong cytotoxic T lymphocyte response against ras(m12)-transfected non immunogenic L5178y target cells. These preliminary results suggest that K-ras mutation could down-regulate the level of tumor immunogenicity, possibly acquired through a mutagenic process affecting other unrelated genes.

Animals↗
PubMed1996

In vitro inactivation of human O6-alkylguanine DNA alkyltransferase by antitumor triazene compounds.

The cytotoxic and mutagenic properties of antitumor triazene compounds (TZC) have been mainly attributed to their ability to form DNA adducts at the O6 position of guanine. Repair of these lesions is mediated by O6-alkylguanine DNA alkyltransferase (OGAT) in an autoinactivating reaction. Therefore when lesion repair has occurred, cells are depleted of OGAT until synthesis of new enzyme molecules takes place. In this study, we have evaluated the ability of DNA alkylated by different TZC to deplete OGAT activity. Moreover, we have also investigated whether these compounds might inactivate the OGAT enzyme by a direct reaction with the protein. Human OGAT protein was partially purified from insect cells infected with a recombinant baculovirus containing the human OGAT coding sequences. Thereafter human OGAT protein was exposed directly to TZC or to TZC-alkylated DNA. Among the TZC tested, p-(3-methyl-1-triazeno)benzoic acid was the most effective OGAT inactivator by direct interaction with the protein. Moreover DNA substrates treated with methylating TZC, such as temozolomide or p-(3-methyl-1-triazeno)benzoic acid, were more effective in depleting the repair enzyme, compared to DNA pretreated with the chloroethylating TZC mitozolomide. In conclusion, our results show that TZC inactivate in vitro OGAT activity by either direct or indirect mechanisms. Therefore TZC are good candidates for 1) increasing their own cytotoxicity, if used according to appropriate dose and treatment schedules and 2) reversing tumor cell resistance to O6-guanine alkylating agents.

Animals↗
PubMed1996

Drug-induced changes of carcinoembryonic antigen expression in human cancer cells: effect of 5-fluorouracil.

Previous studies showed that 5-fluorouracil (5-FU) is capable of enhancing the membrane reactivity of the human colon carcinoma cell line HT-29 with a monoclonal antibody (COL-1) directed against carcinoembryonic antigen (CEA). In the present study, we show that short-term exposure (i.e., 1 hr) of cancer cells to 5-FU mediates a marked increase of CEA expression, that is concentration-dependent and lasts up to day 5 after treatment. This phenomenon is the result of the drug-mediated enhancement of the CEA expression, but not of the selection of the CEA-positive cells operated by the antimetabolite. This is supported by the finding that the increase of the CEA expression detected by cytofluorimetric analysis is observed not only in the parental HT-29 line, but also in its C22.20 subclone, endowed with a low basal level of CEA and with chemosensitivity to 5-FU lower than that of the parental cell line. Moreover, increase of CEA expression occurs not only in the plasma membrane, but also in the cytosolic cellular compartment, as indicated by the results of Western blot analysis. Northern blot analysis of total RNA extracted from 5-FU-treated HT-29 or C22.20 cells shows an increase in the steady-state levels of CEA and CEA-related transcripts (e.g., biliary glycoprotein). Moreover 5-FU-mediated augmentation of the CEA transcript appears to be attributable mainly to enhanced transcription rather than to increased mRNA stability. It is concluded that induction of enhanced CEA protein expression in cancer cells treated with 5-FU could be of clinical interest for the development of immunochemotherapeutic protocols based on CEA protein as the target molecule.

Carcinoembryonic Antigen↗
PubMed1995

O6-alkylguanine-DNA alkyltransferase attenuates triazene-induced cytotoxicity and tumor cell immunogenicity in murine L1210 leukemia.

Methylating and chloroethylating triazene compounds (TZCs) are effective antitumor agents in murine leukemias and can induce the appearance of novel antigens in leukemic cells (chemical xenogenization). Recently, it has been shown that TZCs might have a role in the treatment of patients affected by acute myelogenous leukemias that express low levels of the DNA repair enzyme, O6-alkylguanine-DNA alkyltransferase (OGAT). In this report, we have evaluated the role of this DNA repair enzyme in the leukemic cell response to the xenogenizing and cytotoxic properties of TZCs. OGAT-deficient murine leukemic L1210 cells were transfected with a recombinant ecotropic retrovirus containing the coding region for the human OGAT protein. Selected clones expressed the human OGAT transcript and had greatly increased OGAT activity. Compared to OGAT-deficient cells, OGAT-expressing cells were considerably more resistant to the xenogenizing properties of 1-(p-chlorophenyl)-3,3- dimethyl-triazene, measured in terms of leukemia graft rejection, and were less susceptible to the cytotoxic activity of the TZCs 8-carbamoyl-3-methyl-imidazo [5,1-d]-1,2,3,5-tetrazin-4(3H)-one and 8-carbamoyl-3-(2-chloroethyl)imidazo [5,1-d]-1,2,3,5-tetrazin-4(3H)-one. These data suggest that methylation of the O6 position of guanine is involved in the appearance of increased tumor immunogenicity after exposure to methylating TZC and that OGAT is able, at least in part, to counteract the cytotoxic effects of methylating and chloroethylating agents.

Animals↗
PubMed1989

Evaluation of the oral toxicity of spinacine hydrochloride in a 13-week study in rats.

Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid), the major reaction product of formaldehyde added to Grana Padano cheese, was administered to five groups of ten rats of each set at dietary concentrations that provided doses of O (control), 15, 30, 60 or 300 mg/kg body weight/day for 13 wk. There were no adverse effects upon survival, growth or food intake. No significant treatment-associated changes were found in haematological parameters, in serum chemistry or organ weights at the end of the study. At autopsy, neither gross nor histological modifications were attributable to treatment with spinacine. In this study the no-effect dose level for spinacine was considered to be 300 mg/kg body weight/day.

Administration, Oral↗
PubMed1988

Ferric chondroitin 6-sulfate (Condrofer): a new potent antianaemic agent with a favourable pharmacokinetic profile.

One and 3 mg/kg iron as Condrofer**, a new soluble formulation of this metal, and 1 mg/kg iron as Proteoferrina*** or ferritin were given orally for 4 weeks to male rats in which severe experimental anaemia had previously been induced (by iron-deficient diet and repeated bleedings). Haematological (erythrocyte count, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, reticulocytes and leukocytes) and blood chemistry (sodium, potassium, iron and total protein) parameters were checked weekly and at the end of the drug administration period. Clinical and behavioral signs, body weight, food intake and necroscopic observations were also recorded. Condrofer time- and dose-dependently improved the general blood picture, the clinical data and the autoptic findings to the point of making these animals significantly approach control rats, save for one parameter, sideremia, which after 4 weeks of treatment remained lower than normal. The most plausible explanation would seem that the severe anaemia interfered both with the physiological iron storage and with the iron-dependent mitochondrial enzymatic systems. Iron (1 mg/kg) daily as Proteoferrina or ferritin was significantly less effective than when this metal was administered as Condrofer, since all the haematological parameters and the clinical, behavioral signs and necroscopic observations were less favourable. The more complete reversal of anaemia in the rats that received Condrofer is, most probably, due to the higher bioavailability of iron administered under this formulation, as demonstrated by iron kinetics after equidoses of iron as Condrofer and Proteoferrina.

Anemia, Hypochromic↗
PubMedDate not supplied

Toxicological evaluation of u-hEGF.

The toxicological evaluation of urinary human epidermal growth factor (u-hEGF) included mutagenicity, single and repeated dose general toxicity, and teratogenicity studies in various animal species. The mutagenic potential of u-hEGF was tested in vitro (Ames test, chromosome aberration in human lymphocytes, unscheduled DNA synthesis in HeLa cells) and in vivo (chromosome aberration in Chinese hamster bone marrow and micronucleus test in rat bone marrow). No mutagenic or clastogenic effects were found. The acute toxicity of u-hEGF was evaluated in mice and rats, using single subcutaneous (sc) or intravenous (i.v.) injection of 15 mg/kg. No toxic effects were observed Four-week i.v. daily administration of u-hEGF at the doses of 0.3, o.9, and 3 mg/kg in the SD rat followed by 2 wk of compound withdrawal induced pronounced and generally dose-related effects (i.e., epithelial hyperplasia) in a wide range of tissues and organs, at all doses. However, these effects were not apparently detrimental to the general health of the rats. The repeated sc administration of u-hEGF to cynomolgus monkeys for 4 wk at the same doses as used in the rat study resulted in lethality after about 7 days of treatment in the 2 higher dose groups or after 14 days at the lowest dose. The main clinical signs observed were gastrointestinal effects, respiratory distress, sedation, marked loss of body weight, and cutaneous desquamation. At histology, hyperplasia of most epithelia was seen in all groups. In addition, atrophy of the ovarian follicles and necrosis of the uterine endometrium were noted. Changes considered secondary to physical distress were atrophy of the hemopoietic and lymphatic system and hepatic steatosis. The embryofetal toxicity and teratogenicity of u-hEGF was tested, using the i.v. route in the SD rat and the i.v. and sc routes in the New Zealand White rabbit. In both species, the compound was administered at the doses of 0, 0.3, 0.9, and 3 mg/kg/day, from day 6 to 15 of pregnancy in rats and 6-18 in rabbits. In the rat, an increase in body weight was noted in the dams and fetuses at the 2 high doses. No embryotoxic or teratogenic effects were observed. In the rabbit studies, mortality and severe clinical signs involving various systems, with marked effects on the eyes, were observed at all doses tested during the first days of treatment by both routes. From the reproductive point of view, most of the surviving treated gravid females showed only resorptions.

Animals↗
PubMedDate not supplied

[Prophylaxis of toxic effects on the peripheral venous system associated with intravenous administration of vinorelbine].

Vinorelbine is effective in the treatment of a number of malignancies. However, beside the haematologic and not haematologic toxicity as thrombocytopenia, granulocytopenia, fatigue, paresthesias, nausea and vomiting, one of the most common side effects is the local irritation with thrombophlebitis. The side effect, reported in about 10-26% of patients receiving vinorelbine infusions, is due to the vescicant and irritant action of the drug. Many studies have been performed in order to reduce the incidence of venous irritation either with concomitant administration of anti-inflammatory drugs as defibrotide or ketorolac, or changing infusion schedule from bolus infusion to a 20-30 minute infusion. Aim of this review is to define peripheral venous system toxicity of vinorelbine and the best way of administration.

Anti-Inflammatory Agents↗
PubMedDate not supplied

Effect of 5-fluorouracil on carcinoembryonic antigen expression and shedding at clonal level in colon cancer cells.

BACKGROUND: The carcinoembryonic antigen (CEA) is a tumor marker largely utilized for the detection of minimal disease or as a target of immunotherapeutic approaches. In preclinical models CEA has been found to be up-regulated after exposure of cancer cells to 5-fluorouracil (5-FU). In the present study, the clonal distribution of CEA and its regulation by 5-FU at clonal level was investigated using human HT-29 colon cancer cells. MATERIALS AND METHODS: The extent of CEA expression was measured in terms of: (a) antigen levels on plasma membrane, by flow cytometry; (b) cytoplasm and membrane protein, by Western blot analysis: (c) transcript, by Northern blot analysis; (d) CEA shedding by radioimmunossay. RESULTS: CEA protein and gene transcript were variably expressed among different clones. In all cases 5-FU was able to increase the percentage of CEA-positive cells, the amount of antigen, either in the membrane or cytosolic fractions, and the corresponding transcript. Moreover, a marked increase of CEA shedding was found in drug-treated cells with respect to that of controls. The increase of CEA induced by the antimetabolite was not the result of a selection mechanism based on preferential killing of CEA negative cells. The antimetabolite was capable of enhancing antigen expression also in other CEA-positive tumor cell lines with different basal levels of the marker. CONCLUSIONS: The present findings could be of potential value to increase the sensitivity of diagnostic procedures based on detection of CEA positive tumor cells. Moreover, the antimetabolite might be included in immunotherapeutic protocols to facilitate recognition of CEA-positive cancer cells by immune responses.

Antimetabolites, Antineoplastic↗
PubMedDate not supplied

Chemotherapy with vinorelbine, cisplatin and continuous infusion of 5-fluorouracil in locally advanced breast cancer: a promising low-toxic regimen.

Primary chemotherapy for locally advanced breast cancer, usually an anthracycline-containing regimen, improves local disease control allowing for an initially inoperable tumour to be resected. The feasibility and efficacy of a regimen containing vinorelbine (V), cisplatin (P) and 5-fluorouracil (5-Fu) as continuous infusion (ViFuP regimen) for patients with locally advanced breast cancer were evaluated. Twenty-six patients with a T4 breast cancer presentation (eight also had synchronous distant metastases) were treated with V (20 mg total dose i.v. on day 1 and day 3), P (60 mg/m2 i.v. on day 1) and 5-Fu (200 mg/m2/d as continuous infusion) all given every 3 weeks for a maximum of 6 courses. Eleven patients had an inflammatory breast lesion, 4 had a T4a and 11 a T4b presentation. Among those with metastases, 6 had one site and 2 had two sites of disease. After chemotherapy all tumors except one became operable. Objective response was observed in 19 out of the 26 evaluable patients (73%; 95% CI: 52-88%): fourteen had a partial response (54%); 5 had a clinically complete response (19%) and 5 had complete pathological response (20%; 95% CI: 7-41%). Seven patients had stable disease (27%) while no disease progression under treatment occurred. Mild or moderate side-effects included neutropenia (G1-G2 in 58% and G3 in 31% of patients), anemia (G1 in 19%), nausea and/or vomiting (G1-G2 in 92% of patients), mucositis (G1-G2 in 23%), diarrhea (G1 in 19%), plantar-palmar erythema (G1 in 12%) and alopecia G1 in 27% of patients. We conclude that the ViFuP regimen is well-tolerated and its use results in a high response rate. Thus ViFuP may be considered a relevant alternative to more toxic regimens, with an acceptable response rate. Despite the lack of a formal demonstration of equal efficacy with more toxic regimens commonly applied in locally advanced breast cancer, testing new modalities or drugs might provide a more fruitful strategy for relevant therapeutic progress.

Adult↗
PubMedDate not supplied

Platelet gel biotechnology applied to regenerative surgery of intrabony defects in patients with refractory generalized aggressive peridontitis. Case report.

Platelet gel biotechnology, a method which has all the components of "tissue engineering" techniques, potentiates the already known healing process of guided tissue regeneration procedures (GTR) by multiplying the number of molecules that activate the healing response and by grafting in the host site various cell types, among which stem cells. Here are reported cases of patients affected by refractory generalized aggressive periodontitis treated with the association GTR and platelet gel biotechnology to verify if the contribution of the gel would produce superior results than those obtained by surgery alone which had been previously applied to the same sites with negative results. Three patients in therapy from 4 to 11 years, already subjected to surgery (GTR) and antibiotic therapy, were reoperated with the adjunct of autologous platelet gel. At a distance of 15.2 months (range 11-17 months) the operated sites showed a reduction in probing pocket depth of 3.4 mm (range 2.8-4.8 mm) and a gain in clinical attachment level of 3.1 mm (range 3-3.5 mm). The association of platelet gel biotechnology with GTR in the surgical treatment of intrabony defects of refractory generalized aggressive periodontitis patients seems to produce results similar to those reported for patients with chronic adult periodontitis. The observations at 15.2 months indicate that there is a stability over time of the results in those sites where previous surgical therapy had shown relapse.

Adult↗
PubMedDate not supplied

Groove associated periodontitis: classification proposal and clinical. Case report.

The presence of a palatoradicular groove (PRG), more frequently observed at the level of the upper lateral incisors, may compromise both the radicular pulp and the periodontium leading to endodontic-periodontal lesions. Frequently, the prognosis of these elements is compromised because of the missed diagnosis or because of the complex therapeutic approach that is necessary to cure the associated pathologies. A histopathological and clinical classification is proposed showing according to the degree of the affected tooth involvement. Preventive measures are also discussed and a clinical case is reported. A 49-year-old woman presented with a PRG at the superior left lateral incisor, endodontically treated years before, associated with probing pocket depths of 10 mm and 7 mm, clinical attachment loss of 11 mm and first degree mobility. The tooth was treated with splinting, periodontal surgery with radiculoplasty, root surface conditioning, guided tissue regeneration and with a prosthetic crown for esthetic rehabilitation. Six years later, the operated site showed probing pocket depths of 3 mm, gains in clinical attachment level of 4 mm and 7 mm and reduction of tooth mobility. The ceramic crown re-established an acceptable esthetics for the patient. Even in the presence of a 3(rd) degree PRG, according to the classification presented, the prognosis of the tooth may be positive through the association of root canal treatment, periodontal and prosthetic therapy. The classification presented shows the clinician the best therapeutic approach.

Female↗
PubMedDate not supplied

A phase II study of primary dose-dense sequential doxorubicin plus cyclophosphamide and docetaxel in cT4 breast cancer.

BACKGROUND: Dose-dense chemotherapy with anthracyclines and taxanes has improved either disease free survival or overall survival in high risk patients with early breast cancer. PATIENTS AND METHODS: The activity and safety of a dose-dense schedule (q14 days) of adriamycin 60 mg/sqm and cyclophosphamide 600 mg/sqm (AC) x 4 cycles followed by docetaxel 75 mg/sqm for 4 cycles with hematopoietic support in patients with stage IIIB breast cancer was explored. Patients with ER > or =10% tumors received concomitant endocrine therapy with 3-month triptorelin and letrozole. RESULTS: Fifteen patients with histologically proven cT4b (three patients) and cT4d (twelve patients) M0 breast cancer were enrolled. Median age was 48 years (range 25-66). Eight clinical responses including one pathological complete remission (pCR), three stable disease (including minor responses) and four progression of disease, one during AC and three during taxotere, were observed. Four patients had grade 3-4 non hematological toxicities and all except one discontinued treatment. CONCLUSION: Due to the high rate of progressive disease, this schedule should not represent a standard option in cT4 breast cancer.

Adult↗