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Biomedical subjects

G Milano

Publications and source records attributed to G Milano.

At least 127 records · Page 7Linked to original sources
PubMed1994

Wide range for optimal concentration of folinic acid in fluorouracil modulation--experimental data on human tumour cell lines.

The clinical use of the fluorouracil (FU)-folinic acid (FA) combination is hampered by the still open choice of the optimal schedule, with marked controversy as concerns the optimal FA dose. This in vitro study on FU-FA combinations in 17 human cancer cell lines, representative of tumour types responding to FU-FA treatment, reassesses the notion of the optimal FA concentration. Cells were exposed for 5 days to various FU-FA concentrations (0.07-77 microM, 14 concentrations, for FU; and 0.0025-100 microM for FA). The growth inhibition was assessed by the MTT test. The investigated cell lines exhibited FU IC50 ranging from 0.4 to 38.9 microM (median 3.7 microM). In six out of 17 cell lines investigated, the addition of FA did not result in a substantial enhancement of FU cytotoxicity (group 1). For the remaining 11 cell lines responding to FA supplementation (group 2), the maximal enhancement factor ranged from 3 to 8, meaning that in the presence of optimal FA concentration, the efficient FU concentration (IC50) was reduced by between 3 and 8 as compared to the efficient FU concentration without FA supplementation. For cell lines responding to FA supplementation, the optimal FA concentrations ranged from 10(-7) to 4 x 10(-4) M (4000-fold range) with a median value at 9.6 x 10(-7) M. Distribution of cell doubling time was not significantly different between group 1 and group 2. In contrast, the FU IC50 were significantly different (P = 0.02) between group 1 (median 7.4 microM) and group 2 (median 2.2 microM), thus indicating that cell lines with the greatest FU cytotoxicity enhancement by FA were those intrinsically sensitive to FU and vice versa.

Breast Neoplasms↗
PubMed1994

[Evolution from pharmacokinetics to pharmacogenetics. The example of 5-fluorouracil].

5FU tends to be used more and more frequently; this fact can be explained by its modulation, mainly by folinic acid. Pharmacokinetic follow-up of 5FU with dose adaptation has demonstrated its clinical usefulness by reducing significantly drug side-effects without any impairment in tumor response. Whatever the anticancer drug considered, it is theoretically possible to predict individual capacities for clearing it. This possibility has been explored for 5FU. Among the different tested variables only gender has a determined influence with females showing an average 15% reduction in 5FU clearance as compared to males. Age, hepatic function, nutritional status have no clear influence on 5FU clearance. 5FU catabolism is governed by a key enzymatic step involving dihydropyrimidine dehydrogenase (DPD). Recent case reports have shown that patients with partial or total DPD deficiency shown in lymphocytes were exhibiting severe 5FU related toxicities. A positive and significant correlation has been established between 5FU clearance and DPD activity measured in lymphocytes. This correlation is too weak for allowing individual 5FU dose to be calculated on the basis of lymphocyte DPD activity. Nevertheless DPD determination may allow high risk patients, with partial or total DPD deficiency to be identified.

Female↗
PubMed1994

Multidrug resistance circumvention by a new triazinoaminopiperidine derivative S9788 in vitro: definition of the optimal schedule and comparison with verapamil.

The current work was undertaken to investigate the importance of exposure sequence and duration in achieving the maximum reversal action of S9788 on doxorubicin (DOX) cytotoxicity against cells that exhibit the (MDR) multidrug resistance phenotype: the MCF7/DOX cell line. Accumulation and release of DOX were examined in this cell line. The reversal effect was compared with that obtained with verapamil. S9788 activity was schedule dependent: when comparing incubation with S9788 before or after treatment with DOX, the best reversal factor was obtained in the case of a post-treatment incubation (65.6 +/- 7.7 vs 20.8 +/- 7.0). S9788 was a more potent modulating agent than verapamil, whatever the schedule of exposure of the cells to the reversal agent. The reversal of resistance after short-term DOX exposures was caused not only by prolonged cellular accumulation of DOX, but also by its prolonged retention after transfer of cells to DOX-free medium. A relationship was noted between cellular exposure to DOX and the cytotoxic effect, and so the reversal of resistance induced by S9788 appears to be directly linked to the level of cell exposure to DOX. This work provided a rationale for improving the schedule of administration of S9788 in clinical trials.

Antineoplastic Agents↗
PubMed1994

Spontaneous or imposed circadian changes in plasma concentrations of 5-fluorouracil coadministered with folinic acid and oxaliplatin: relationship with mucosal toxicity in patients with cancer.

Pharmacokinetics of total platinum, 5-fluorouracil, l-folinic and d-folinic acid, and 5-methyltetrahydrofolate were studied in plasma from nine patients with advanced colorectal cancer treated with oxaliplatin (20 mg/m2/day), 5-fluorouracil (600 mg/m2/day), and folinic acid (300 mg/m2/day). Drugs were administered with a programmable-in-time pump by continuous infusion for 5 days. We compared two drug delivery schedules: constant rate versus chronomodulated rate with peak of oxaliplatin at 4 pm and peak of 5-fluorouracil and folinic acid at 4 am. In the chronomodulated schedule, plasma concentrations of the drugs paralleled the pump functioning: maximum platinum concentration near 4 pm, and maximum 5-fluorouracil and folate concentrations near 4 am. When drugs were administered at a constant rate, mean plasma concentration of 5-fluorouracil varied in a circadian manner each treatment day, that is, a peak at 4 am (approximately 800 ng/ml) and a trough at 1 pm (approximately 100 ng/ml). Mean plasma levels of total platinum and folate compounds increased over the first 24 hours. Total platinum mean level and that of the inactive d-folinic acid isomer reached a constant plasma concentration, whereas biologically active folates exhibited circadian variation in their plasma concentrations (peak around 7 am, trough near 6 pm, and amplitude approximately 10%). Severe mucositis was exhibited by all four patients on the flat schedule, but only by one on the chronomodulated schedule (p < 0.008). Individual pharmacokinetic and toxicity data showed that patients with circadian rhythms in 5-fluorouracil concentrations were least sensitive to 5-fluorouracil-related toxicity. Thus amplification or induction of such rhythm in 5-fluorouracil exposure may permit dose escalation.

Adult↗
PubMed1994

Population study of dihydropyrimidine dehydrogenase in cancer patients.

PURPOSE: We conducted a prospective study on a large set of cancer patients in an attempt to evaluate the incidence of complete or partial dihydropyrimidine dehydrogenase (DPD) deficiency as found in peripheral mononuclear cells (PMNC). PATIENTS AND METHODS: One hundred eighty-five unselected consecutive cancer patients were included. The population consisted of 152 men (mean age, 62.1 years; range, 35 to 90) and 33 women (mean age, 59.2 years; range, 36 to 77). Sixty-eight were head and neck patients treated by a 5-day continuous infusion of fluorouracil (FU; starting dose, 1 g/m2/d, with dose adaptation based on pharmacokinetics) for which DPD activity was measured 2 to 3 days before FU administration (94 cycles analyzed). PMNC-DPD activity was measured by a radio-enzymatic assay using carbon-14-FU. RESULTS: DPD activity in the entire population showed a unimodal distribution, which globally fits a gaussian distribution. Mean and median DPD activity values were 0.222 and 0.211 nmol/min/mg protein, respectively (range, 0.065 to 0.559). No total DPD deficiency was found. Multifactor analysis of variance showed that liver function (biologic evaluation) and age did not influence DPD activity, but that DPD activity was, on average, 15% lower in women (0.194 nmol/min/mg protein) than in men (0.228 nmol/min/mg protein) (P = .03). No difference was demonstrated between premenopausal and postmenopausal women. In patients treated with FU, the risk of developing side effects was not linked to pretreatment DPD activity. FU-related toxicity was linked to FU systemic exposure. The correlation between pretreatment DPD activity and FU systemic clearance (CI) was weak (n = 90, linear regression r = .31, P = .002). Pretreatment DPD activity in patients who required a dose reduction was not significantly different from DPD activity in patients who did not require dose modification. CONCLUSION: From the present study, it appears that total DPD deficiency is a rare event. Although pretreatment DPD activity cannot be a useful indicator for improving FU dose adaptation strategy, the identification of severe DPD deficiency (< 0.100 nmol/min/mg protein) could lead to starting the treatment with a markedly reduced FU dose or even to using an alternative chemotherapy regimen.

Adult↗
PubMed1994

Relationship between fluorouracil systemic exposure and tumor response and patient survival.

PURPOSE: The aim of this study was to analyze the link between fluorouracil (FU) systemic exposure and tumor response and overall survival. PATIENTS AND METHODS: One hundred eighty-six patients (162 men, 24 women) with head and neck cancer were studied. All received cisplatin plus FU for three cycles as first-line chemotherapy. The treatment consisted of cisplatin (100 mg/m2 intravenously [IV]) followed by a 5-day continuous venous infusion of FU (1 g/m2/d). The median follow-up duration for the 104 patients alive was 24 months. For each cycle, we calculated the area under the curve over the duration of pharmacokinetic follow-up (AUC0-105 h) for plasma FU. For each patient, we analyzed the averaged AUC0-105 h and the averaged total dose for the three cycles. RESULTS: The response rate was 30% complete responses (CRs), 22% partial responses (PRs) more than 75%, 25% PRs less than 75%, and 23% no response (NR). Medians for averaged AUC and dose per cycle were 27,906 ng/mL h (first through third quartile, 25,398 to 31,060) and 7,000 mg (first through third quartile, 6,200 to 7,833), respectively. The tumor response was significantly linked to tumor stage (P < .001) and to averaged AUC (P = .05), but not to averaged dose. Analysis of parameters (continuous variable) expressing FU treatment intensity showed that dose did not influence survival contrary to the AUC (P = .001). The AUC remains significant (P = .025) in a multivariate analysis including tumor stage, demonstrating that the greater the FU systemic exposure, the longer the survival. CONCLUSION: These results strengthen the interest of individual FU dose adaptation based on pharmacokinetics.

Adult↗
PubMed1994

[Tamoxifen increases cytotoxic effects of fotemustine. Experimental results on cell lines of human melanoma].

Fotemustine (Fote) is a new aminoacid linked chloroethyl nitrosourea which has been shown to be useful in disseminated malignant melanoma. The aim of the present study was to analyze the cytotoxic effects resulting from the combination of antiestrogens and Fote on human melanoma cell lines. The antiestrogens tested were tamoxifen (TMX 5.10(-7) M and 5.10(-6) M) and 40H TMX (5.10(-8) M and 5.10(-7) M). As a preliminary step, a series of nine human melanoma cell lines was screened in order to identify and quantify the presence of estradiol receptors (ER) in these cell lines. This led to selecting an ER positive (+) cell line. The drugs alone or in combination were then tested against CAL 1 ER (+) and CAL 7 ER (-) melanoma cell lines. Different sequences of drug combinations were tested using clinically compatible drug concentrations. For CAL 1 cells there was a growth inhibitory effect induced by the antiestrogens given alone. Overall, the presence of the antiestrogens resulted in higher cytotoxic effects than when cells were exposed to Fote alone. The lowest IC50 Fote values as compared to Fote alone were generated by the sequences with the antiestrogens administered before Fote. Significantly, these associations with antiestrogens enabled the IC50 values of Fote to be reduced up to 80%. Globally TMX and 40H TMX had similar synergistic effects. TMX and 40H TMX had a modest influence on Fote cytotoxic effects against CAL 7 ER (-) cells. These data may be useful for optimal planning of future clinical trials for malignant melanoma using antiestrogens and nitrosoureas.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

[EGF receptor, a prognostic factor in epidermoid cancers of the upper aerodigestive tracts].

EGFR was determined, before treatment; in tumors biopsies obtained from 109 consecutive patients with head and neck cancer (100 men and nine women), using iodine labelled recombinant EGF. The median age of the study population was 60 years. EGFR levels varied from 2 to 2302 fmol/mg membrane protein (median 71). There was a significant difference of distribution for EGFR levels between stages I and II tumors and stages III and IV tumors (P = 0.03). The EGFR cut-off value for overall survival was 120 fmol/mg protein and the median follow-up was 18 months (3-35) EGFR overexpression was associated with shorter relapse-free (P = 0.0125) and overall survival (P = 0.028). By multivariate analysis the only significant variables were EGFR for relapse-free survival and tumor staging and EGFR for overall survival. Analyzed in 60 patients treated by first-line chemotherapy CDDP-5FU, the longest survival was achieved for patients who had a complete response to chemotherapy and the lowest EGFR levels (P = 0.018). EGFR expression in the primary tumor allows survival among first line chemotherapy responder categories to be discriminated.

Adult↗
PubMed1993

Combination of reduced folates with methotrexate or 5-fluorouracil. Comparison between 5-formyltetrahydrofolate (folinic acid) and 5-methyltetrahydrofolate in vitro activities.

Folinic acid (dlFA) is increasingly used in clinical oncology. The active isomer lFA is intensively metabolized into l5-methyltetrahydrofolate (l5MTHF), the relative proportions of lFA, dFA and l5MTHF in blood varying considerably between oral and i.v. FA administration. The purpose of the study was to compare the in vitro activities of pure lFA and pure l5MTHF at equivalent drug exposure [area under curve (AUC)], taking into account their respective chemical stability in the culture medium. The in vitro growth inhibition [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) test] was evaluated on five human tumor cell lines after methotrexate (MTX)-folate or 5-fluorouracil (5FU)-folate exposures. Not only were the activities of lFA and l5MTHF compared, but also clinically relevant mixtures of lFA + dFA + l5MTHF corresponding to the proportions found at steady state during oral (PO mixture, 4, 39 and 57%, respectively) and i.v. administrations (i.v. mixture, 7, 81 and 12%, respectively). Measurement of folates demonstrated the marked lability of l5MTHF (65.8% loss over 5 days in the culture medium) as compared to lFA (2.6% loss). Whatever the pharmacological model tested (MTX-folate or 5FU-folate), comparison of the folate effects at equivalent drug exposure taking into account their relative stability showed that l5MTHF was never more potent than lFA. Moreover, a higher efficiency of lFA was demonstrated for the cell line most sensitive to 5FU; in this case, as expected, the i.v. mixture was more potent than the PO mixture. This study shows that depending on the tumor, lFA can be more potent than its main circulating metabolite l5MTHF. Along with the limited capacity of oral absorption, the choice between oral and i.v. route for FA administration in patients should take into consideration the different pharmacological activities between lFA and l5MTHF which suggest that the oral route is potentially detrimental to the optimal activity of the 5FU-FA combination as compared to i.v. administration.

Antineoplastic Agents↗
PubMed1993

Tamoxifen enhances the cytotoxic effects of the nitrosourea fotemustine. Results on human melanoma cell lines.

Fotemustine (Fote) is a new amino acid-linked chloroethyl nitrosourea which has been shown to be useful in disseminated malignant melanoma. The aim of the present study was to analyse the cytotoxic effects resulting from the combination of anti-oestrogens and Fote on human melanoma cell lines. The anti-oestrogens tested were tamoxifen (TMX, 5 x 10(-7) mol/l and 5 x 10(-6) mol/l) and 4OH TMX (5 x 10(-8) mol/l and 5 x 10(-7) mol/l). As a preliminary step, a series of nine human melanoma cell lines was screened in order to identify and quantify the presence of oestradiol receptors (ER) in these cell lines. This led to the selection of an ER-positive (+) cell line. The drugs alone or in combination were then tested against CAL 1 ER (+) and CAL 7 ER (-) melanoma cell lines. Different sequences of drug combinations were tested using clinically compatible drug concentrations. For CAL 1 cells, there was a growth inhibitory effect induced by the anti-oestrogens given alone. Overall, the presence of the anti-oestrogens resulted in higher cytotoxic effects than when cells were exposed to Fote alone. The lowest IC50 Fote values as compared to Fote alone were generated by the sequences in which the anti-oestrogens were administered before Fote. Significantly, these associations with anti-oestrogens enabled the IC50 values of Fote to be reduced by up to 80%. Globally, TMX and 4OH TMX had similar synergistic effects. TMX and 4OH TMX had a modest influence on Fote cytotoxic effects against CAL 7 ER-negative cells. These data may be useful for optimal planning of future clinical trials for malignant melanoma using anti-oestrogens and nitrosoureas.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Importance of the irradiation timing within a chemoradiotherapy sequence including cisplatin and 5-FU-folinic acid. Experimental results.

The objective of the present in vitro study was to determine an optimal timing of the irradiation in the combination cisplatin (CDDP) and 5-fluorouracil-folinic-acid (5-FU-FA) allowing a maximal cytotoxic effect on a human cell line derived from a head and neck carcinoma (CAL 27 cells). The various tested chemoradiotherapy sequences were applied in parallel to human keratinocytes in culture (SVK 14 cells). This was done in order to define the best sequence allowing the achievement of an optimal selectivity of the cytotoxic effects. The drug sequence was: CDDP over 2 h then fresh medium was added including the tandem 5-FU-d,I FA applied 6 h after CDDP, for 5 days. Irradiation was applied only once and at various times within the drug sequence. The cytotoxicity effects of the different chemoradiotherapy combinations were assessed by the MTT semi-automated test. The part taken by the 5-FU-FA combinations in the overall cytotoxicity was examined; an effect was apparent on CAL 27 cells only. The evolution of the radiation effect (RE = cell survival after drugs/cell survival after drugs plus irradiation) was analysed as a function of the different times of irradiation within the given drug sequence. Clearly, the RE values were dependent upon time at which the radiation dose in the chemoradiotherapy regimen was administered. For CAL 27 cells, irradiation effects were maximal at the first irradiation time tested after the end of the CDDP exposure (i.e. t = 3.5 h). In contrast, this optimal chemoradiotherapy timing for better cytotoxicity on CAL 27 cells did not correspond to that of SVK 14 cells. Consequently, it was possible to establish that the best time for the selectivity index was located shortly after the CDDP exposure.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Evaluation of the time-schedule dependency for the cytotoxic activity of the new vinca alkaloid derivative, S 12363 (vinfosiltine).

S 12363 is a new vinca alkaloid derivative obtained by appending an optically active alpha-aminophosphonate at the C23 position of 04-deacetyl vinblastine. The present study concerns four different human tumour cell lines, which represent the spectrum of vinca alkaloid clinical activity. The influence of time exposure on S 12363 growth inhibition was studied in vitro. Cells were exposed to the drug during the following exposure times: 5, 15, 30 min and 1, 3, 6, 12, 24, 48, 72, 144 h. The concentrations of S 12363 applied were between 1 x 10(-2) and 1 x 10(3) nmol/l. The cytotoxic effects were assessed by using the methyltetrazolium (MTT) semi-automated test. Considering the IC50 values in terms of concentration (C) x time (T), I (C x T)50, it was shown that for an equal growth inhibitory effect (50% of cell death) the increased exposure times required higher cumulative drug exposures. More precisely, only very long exposure (greater than 24 h) resulted in very high I (C x T)50. The drug exposure ratios which correspond to I (C x T)50 values for 144 h divided by the I (C x T)50 values for 0.25 h ranged between 2.8 and 18.3. If T and C had symmetrical effects on the final growth inhibition, the I (C x T)50 ratios should have been equal to one. For all cell lines investigated there were similar dose-response curves following two types of S12363 exposure: a single day exposure or three successive daily exposures, the total C x T values being the same in both experimental situations. The basic pharmacological information provided by the present study may encourage further clinical trials of this potentially interesting new vinca alkaloid.

Antineoplastic Agents, Phytogenic↗
PubMed1993

Expression of epidermal growth factor receptor and survival in upper aerodigestive tract cancer.

PURPOSE: To determine the expression of epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinoma and to evaluate its prognostic value. MATERIALS AND METHODS: EGFR was determined in tumor biopsies obtained from 109 consecutive patients with head and neck cancer (100 men, nine women). Control biopsies were obtained from 94 patients in a symetric nontumoral area of the same anatomic site. EGFR was measured by a binding assay using human recombinant iodine 125-EGF. RESULTS: The presence of detectable EGFR levels was found in all explored tumors with highly marked differences between patients (median, 71 fmol/mg protein; range, 2 to 2,302). In 93 of 94 cases, EGFR levels were higher in tumor samples as compared with healthy control zones. There was no significant difference in EGFR expression according to the various anatomic sites explored or tumoral differentiation status. There was a significant difference of distribution for EGFR levels between stages I and II tumors and stages III and IV tumors. The tumor EGFR levels were not linked to the response to first-line chemotherapy by cisplatin (CDDP) and fluorouracil (5FU). Survival was assessable for 103 patients for overall survival and for 81 patients for recurrence. EGFR overexpression was associated with shorter relapse-free (P = .0125) and overall survival (P = .028) rates. By multivariate analysis, the only significant variable was EGFR for relapse-free survival and tumor staging for overall survival. The association of EGFR to tumor staging markedly improves the significance for overall survival predictability (P = .002). CONCLUSION: EGFR determination deserves particular attention in head and neck cancer, since it independently carries a strong prognostic value.

Adult↗