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Biomedical subjects

G Milano

Publications and source records attributed to G Milano.

At least 145 records · Page 8Linked to original sources
PubMed1993

[Demonstration and characterization of EGF receptors in cancer of the uterine cervix].

Epidermal Growth Factor in a polypeptide growth factor of which receptor EGFR has a prognosis value for some malignant tumours. Data are limited concerning the EGFR value in cervix tumours. EGFR was measured in biopsies obtained in cervix cancer patients before any treatment. Twenty-two patients (18 squamous carcinomas, 4 adenocarcinomas) were studied. EGF binding was characterized in seven tumour samples. Scatchard representation identified a single family of binding sites. Kd value revealed high affinity for EGF binding: 0.645 +/- 0.769 nmol/l. EGFR values were determined by a simplified competition method using a radiolabeled ligand. EGFR was found to be more elevated in tumours (n = 20) than in normal tissue (n = 4): (59.5 vs 10.5 fmol/mg proteins). There was a tendency for higher EGFR values in squamous tumours (m = 83.5 fmol/mg proteins) as compared to adenocarcinomas (m = 35.5 fmol/mg proteins), P = 0.09. There was no difference in the distribution of EGFR values according to tumour differentiation and staging. This work confirms the presence of EGFR in cervix tumours. Interestingly, we found that tumours with high EGFR values were more radiosensitive than tumours with low values.

Adenocarcinoma↗
PubMed1993

[l-folinic acid versus racemic folinic acid in the treatment of leukemia in children with high dose of methotrexate].

Until now, folinic acid (FA) has been available the racemic mixture d1 FA, whose biological activity is supported by natural 1 FA. The purpose of this trial was to compare, on a pharmacokinetic, biological, and clinical basis, the racemic mixture dl FA with the pure 1 FA in the rescue of high-dose methotrexate (MTX) therapy. Eighteen children with acute lymphocytic leukemia (ALL) were entered in this trial planned with a cross-over design. Four cycles of MTX (5 g/m2, 24h CVI) were administered to each patient, with a 2-week interval between cycles. The rescue was achieved orally every 6h, starting 12h after the end of the MTX infusion, at a dose of 12 mg/m2 for dl FA and 6 mg/m2 for pure 1 FA. dl FA and 1 FA rescues were alternated from one cycle to the next. d FA, 1 FA, and the active metabolite 5-methyltetrahydrofolate (5-MTHF) were measured in plasma using a stereospecific HPLC assay. After administration of dl FA, the accumulation of d FA in plasma was confirmed: mean residual concentrations were 420 and 652 nM after 2 and 6 intakes respectively. Total active folate concentrations (1 FA + 5-MTHF) were similar between the two types of rescue: 92 and 100 nM respectively for dl FA rescue and 1 FA rescue after two intakes, 186 and 184 nM respectively for dl FA rescue and 1 FA rescue after six intakes. Intra-individual statistical analysis of total active folates (1 FA + 5-MTHF) performed on 17 patients did not show any significant difference between dl FA rescue and 1 FA rescue. For both types of rescue, MTX terminal half-lives were identical (average value 13.9 h). Considering each type of toxicity (hematologic, hepatic, renal and digestive) there was no significant difference in the proportion of toxic cycles following l FA rescue or dl FA rescue. In conclusion, the administration of the pure l FA, as compared with the administration of the racemic mixture, results in comparable blood profiles of active folates and MTX, and leads to equivalent treatment tolerance.

Adolescent↗
PubMed1993

[Clinical pharmacokinetics and practical consequences of optimal use of medroxyprogesterone acetate].

Medroxyprogesterone acetate (MPA) is one of the major drugs used in endocrine therapy for advanced breast cancer. However, its optimal dose is still not clearly established. Response to treatment and drug-related side effects were analyzed as a function of plasma MPA concentrations during prolonged MPA administration. MPA plasma concentrations were measured (HPLC assay) at steady state (Css min) in 129 patients (mean age 63 years, 34-87) treated by MPA (111 being treated orally exclusively, with daily doses ranging from 400 to 2000 mg). A wide inter-patient variability was noted in MPA Css min for the 70 patients receiving 1000 mg/day per os: median 51 ng/ml, range 10-269 ng/ml. Intra-patient analysis of the evolution of MPA Css min during prolonged treatment showed relative stability of MPA concentrations (mean coefficient of variation = 21%). A weak but nevertheless significant correlation was demonstrated between oral doses and MPA Css min (P = 0.016). Thirty-five percent of patients (45/129) developed MPA-related side effects which were associated with the highest plasma MPA concentrations: medians were 81 and 32 ng/ml for toxic and non-toxic treatments respectively (P < 0.001). Moreover, the cumulative incidence of side-effects constantly increases with the elevation of Css min. Objective response was assessable in 55 patients treated by MPA exclusively. Plasma MPA concentrations were significantly different between patients with PD and those with either CR, PR or SD: medians were 46 and 65 ng/ml respectively (P = 0.025). The cumulative incidence of objective response increases up to 70 ng/ml. Analysis of toxicity and response as a function of the oral dose did not reveal any significant relationship. These data suggested an optimal therapeutic window for MPA Css min located within 50-70 ng/ml. This study demonstrates that, as opposed to the administered dose, plasma MPA concentration is a determining factor for toxicity and response to therapy.

Adult↗
PubMed1993

HPLC of folinic acid diastereoisomers and 5-methyltetrahydrofolate in plasma.

We present a rapid, sensitive, and automated HPLC method with direct resolution of l-folinic acid (l-FA), d-folinic acid (d-FA), and 5-methyltetrahydrofolate (5MTHF) from plasma samples. Plasma (500 microL) is first extracted on solid phase (RP-18 cartridge). The dI-FA peak is collected on-line from a reversed-phase column (RP-8, 119 x 2 mm, 4 microns: HPLC 1) and then automatically loaded onto a chiral stationary phase (human serum albumin, 150 x 4.6 mm, 7 microns: HPLC 2). The same mobile phase flows in both systems (0.2 mol/L Na2HPO4:1-propanol, 98:2, pH 6.2). HPLC 1 allows quantification of 5MTHF by absorption at 313 nm; HPLC 2, the quantification of l-FA and d-FA by electrochemical detection in the oxidation mode (total run time 18 min). Recoveries are > 80%. CVs for intra- and interassay reproducibilities are < 5% and 15%, respectively. Linearity of the response (0.1-1 mumol/L and 1-50 mumol/L, r = 0.99, P < 0.01) is satisfactory. The sensitivity limit is 50 nmol/L for 5MTHF and 20 nmol/L for l-FA and d-FA. This assay is substantially improved over existing methods regarding feasibility and is being used in pharmacokinetic investigations in cancer patients.

Acetaminophen↗
PubMed1992

l-folinic acid versus d,l-folinic acid in rescue of high-dose methotrexate therapy in children.

BACKGROUND: At this time, folinic acid (FA) is commercially available as the racemic mixture d,l-FA, whose biological activity is supported by natural l-FA. The administration of d,l-FA results in the accumulation of d-FA in plasma relative to the active l-FA form; in vitro studies have shown that d-FA can compete with the polyglutamation of methotrexate (MTX). PURPOSE: Our purpose was to compare, on a pharmacokinetic, biological, and clinical basis, the racemic mixture d,l-FA with the pure l-FA in rescue of high-dose MTX therapy (5 g/m2) in children with acute lymphocytic leukemia (ALL). METHODS: Eighteen children with ALL were entered in this trial, which was planned with a crossover design. Four cycles of MTX were administered to each patient, and rescue was achieved orally every 6 hours at a dose of 12 mg/m2 for d,l-FA and 6 mg/m2 for pure l-FA. The d,l-FA and l-FA rescues were alternated from one cycle to the next. d-FA, l-FA, and the active metabolite 5-methyltetrahydrofolate (5-MTHF) were measured in plasma using a stereospecific high-performance liquid chromatography assay. RESULTS: Considering total active folate levels (l-FA + 5-MTHF), mean residual concentrations were similar for rescue by d,l-FA and l-FA, after two and six intakes, respectively: 92 and 186 nM for d,l-FA rescue versus 100 and 184 nM for l-FA rescue. Intra-individual comparison of total active folates (l-FA + 5-MTHF) did not show any significant difference between d,l-FA rescue and l-FA rescue. After administration of d,l-FA, the accumulation of d-FA in plasma was confirmed. For both types of FA rescue, MTX terminal half-lives were identical (average value, 13.9 hours). Considering each type of toxic effect (hematologic, hepatic, renal, and digestive), there was no significant difference in the proportion of toxic cycles following l-FA rescue or d,l-FA rescue. CONCLUSION: The administration of the pure l-FA, compared with the administration of the racemic mixture, results in comparable blood profiles of active folates and MTX, leads to equivalent treatment tolerance, and avoids the plasma accumulation of d-FA.

Adolescent↗
PubMed1992

Correlation between dihydropyrimidine dehydrogenase activity in peripheral mononuclear cells and systemic clearance of fluorouracil in cancer patients.

Dihydropyrimidine dehydrogenase (DPD) is the initial key enzyme in the catabolism of 5-fluorouracil (5-FU). We measured DPD activity in lymphocytes from 57 consecutive head and neck cancer patients while simultaneously monitoring 5-FU pharmacokinetics during 5-day, continuous infusion (1000 mg/m2/day) 5-FU therapy (82 cycles in total). The mean value for DPD activity was 0.186 +/- 0.068 (SD) nmol/min/mg of protein (range, 0.058 to 0.357). The mean value for 5-FU clearance was 2522.6 +/- 684.2 ml/min/m2 (range, 1052 to 4029). A significant linear correlation was observed between DPD activity and 5-FU clearance (r = 0.716, P less than 0.0001). DPD activity was poorly correlated to plasma uracil concentrations (r = -0.260, P = 0.0215). Likewise, plasma uracil concentrations were poorly correlated to 5-FU clearance (r = -0.214, P = 0.0595). In patients evaluated for more than one cycle (n = 18), there was large intrapatient variability in both DPD activity and 5-FU clearance. No significant difference was noted between cycles for DPD activity or 5-FU clearance (Kruskal-Wallis test). Monitoring DPD activity in lymphocytes may be useful in identifying patients at risk for altered 5-FU disposition.

Adult↗
PubMed1992

Doxorubicin weekly low dose administration: in vitro cytotoxicity generated by the typical pharmacokinetic profile.

The cytotoxic effects of prolonged exposure to low concentrations of doxorubicin or a doxorubicin bolus were examined in vitro on four human breast cancer cell lines to simulate the plasma concentration profile of weekly low-dose (WLD) doxorubicin in breast cancer patients. Cells were exposed to doxorubicin for various prolonged times (24, 72, 120 and 192 h) and with different drug concentrations (5, 10, 20, 50 and 80 nmol/l). In a series of parallel experiments, cell lines were placed in contact with the drug for short periods (1 h) before prolonged exposure to doxorubicin; the concentrations of these pulses were 150, 250 and 350 nmol/l. A constant decrease in tritiated thymidine incorporation was noted as a function of the drug concentration and the duration of the cell contact with the drug. Interestingly the lowest concentrations (5-10 nmol/l) produced marked cytotoxic effects. For equivalent concentration x time values, experiments including doxorubicin pulses resulted in greater cytotoxicity than continuous exposure alone, in a dose-related manner. This finding was related to differences in intracellular doxorubicin concentrations. Results suggest that the rather empirically designed WLD doxorubicin schedule can generate greater cytotoxic effects than continuous doxorubicin administration alone.

Breast Neoplasms↗
PubMed1992

Effects of prolonged exposure to cisplatin on cytotoxicity and intracellular drug concentration.

The present study was designed to analyse the cytotoxic effect of cisplatin in vitro as a function of various exposure times (up to 120 h), keeping constant the parameter C x T (product of the drug concentration per time). Intracellular drug concentrations were measured in parallel following analysis of cisplatin influx and efflux characteristics. A head and neck cancer cell line was selected to represent the spectrum of cisplatin antitumour activity. The IC50 values (micrograms/ml) for 1, 2, 11 and 121 h were, respectively 4.51, 2.73, 0.27 and 0.151. Reduction of the IC50 was clearly not linearly related to prolongation of the cisplatin exposure time. The kinetics of cisplatin incorporation into CAL 27 cells was investigated as a function of different cisplatin concentrations. A plateau was reached after 16 h of contact. For the extracellular cisplatin concentrations of 1, 2.5, 5 and 10 micrograms/ml, the average intracellular Pt concentrations at the plateau were, respectively (ng/10(6) cells): [mean (S.D.)] 12.8 (0.98), 31.11 (5.12), 71.38 (6.03) and 136.7 (16.5). Intracellular Pt concentrations were linearly related to the extracellular drug concentration (r = 0.99). The drug left the cells following a two-slope kinetics pattern with an alpha half-life of 1.29 h and a beta half-life of 94.4 h. The cytotoxic effect for a given C x T clearly differed for the different cisplatin exposure times. The longest exposure time (121 h) gave the least pronounced cytotoxicity. The intracellular Pt concentrations were linearly related to the C x T values. Cisplatin levels were much lower after the 121 h exposure. These data may prove valuable in establishing a rationale which can aid in selection of optimal modes of clinical cisplatin administration.

Carcinoma, Squamous Cell↗
PubMed1992

Long-term stability of 5-fluorouracil and folinic acid admixtures.

5-Fluorouracil (5-FU) and d,1-folinic acid (FA) are used in association to treat a wide variety of malignancies. The stability and the compatibility of 5-FU and FA in combination in intravenous admixtures were studied under various storage conditions and with drug concentrations matching their clinical use (0.9% sodium chloride, 5% dextrose, protected from light or not). 5-FU and FA concentrations (mg/ml) were 6.5 or 50 and 4.0 or 30.8, respectively. Successive aliquots of the drugs mixtures were withdrawn during 60 h from 500 ml glass bottles and 500 ml polyvinyl chloride (PVC) bags (at room temperature) and during 120 h from cassettes (at 32 degrees C). Drug concentrations were measured by high performance liquid chromatography. For all conditions tested, the changes in 5-FU and FA relative to the initial concentrations remained within the assay reproducibility (10%). In complement, infrared Fourier transformation spectrophotometry has not shown a significant fixation of FA or 5-FU on the PVC bags, in all tested conditions. Under the conditions examined above 5-FU and FA can be mixed in the same container for their use in cancer chemotherapy. This can have practical consequences by simplifying the widely used treatment protocols associating 5-FU and FA.

Drug Combinations↗
PubMed1992

Influence of sex and age on fluorouracil clearance.

PURPOSE: Currently, fluorouracil (5-FU) is one of the major drugs used in cancer chemotherapy. Several investigators, including ourselves, have demonstrated a link between abnormalities in 5-FU clearance (Cl) and the risk of developing more or less 5-FU-related toxicities. Age and sex are among the host factors that have been implicated in the pharmacokinetic variability of drugs. Presently, no data are available on the possible influence of sex and age on 5-FU Cl. PATIENTS AND METHODS: Three hundred eighty patients (mean age, 61.7 years; range, 25 to 91; 301 men and 79 women) with squamous cell carcinoma (sre) of the head and neck were treated in our institution between 1987 and 1991. 5-FU Cl was determined for a total of 1,092 chemotherapy cycles. Each cycle consisted of cisplatin and 5-day continuous intravenous infusion 5-FU (daily doses ranging between 365 and 1,224 mg/m2). RESULTS: 5-FU Cl values (L/h/m2) showed a wide dispersion for both men (median, 179; range, 29 to 739) and women (median, 155; range, 56 to 466). 5-FU Cl values were lower significantly for women compared with men (P = .0005). When adjusted for age and dose, the influence of sex on log Cl remained significant (P = .013). There was no evidence that age modified 5-FU Cl when adjusted for sex and dose. Interestingly, for both men and women, the oldest patients (greater than 70 years) maintained their ability to clear 5-FU with daily doses that ranged from 500 to 1,000 mg/m2. CONCLUSIONS: These data indicate that the capacities to clear 5-FU are lower in women compared with men and are not influenced by age. It would be of interest to know whether this sex-related difference in 5-FU Cl may be clinically relevant by considering both toxicity and tumor response to 5-FU treatment.

Adult↗
PubMed1992

Pharmacokinetics and pharmacodynamics of medroxyprogesterone acetate in advanced breast cancer patients.

PURPOSE: Medroxyprogesterone acetate (MPA) is one of the major drugs used in endocrine therapy for advanced breast cancer. However, its optimal dose still has not been clearly established. Response to treatment and drug-related side effects were analyzed as a function of plasma MPA concentrations during prolonged MPA treatment. PATIENTS AND METHODS: MPA plasma concentrations were measured (high-performance liquid chromatography [HPLC] assay) at steady state (Css min) in 129 patients (mean age, 63 years; range, 34 to 87) treated by MPA (86% were treated orally exclusively with daily doses ranging from 400 to 2,000 mg). RESULTS: A wide interpatient variability was noted in MPA Css min for the 70 patients who received 1,000 mg/d orally (median, 51 ng/mL; range, 10 to 269 ng/mL). Intrapatient analysis of the evolution of MPA Css min during prolonged treatment showed relative stability of MPA concentrations (mean CV, 20.6%). A weak but significant correlation was demonstrated between oral doses and MPA Css min (P = .016). Thirty-five percent of patients (45 of 129) developed MPA-related side effects that were associated with the highest plasma MPA concentrations; medians were 81 and 32 ng/mL for toxic and nontoxic treatments, respectively (P less than .001). Objective response was assessable in 55 patients who were treated by MPA exclusively. Plasma MPA concentrations were significantly different (P = .025) between patients with progressive disease (PD) (median, 46 ng/mL) and those with complete response (CR), partial response (PR), or stable disease (SD) (median 65 ng/mL). Comparison of CR plus PR versus SD versus PD showed only a tendency toward significant differences in MPA Css min (P = .07). Analysis of toxicity and response as a function of the oral dose did not show any significant relationship. These data suggested an optimal therapeutic window for MPA Css min located within 50 to 70 ng/mL. CONCLUSION: This study demonstrates that plasma MPA concentration, as opposed to the administered dose, is a determining factor for toxicity and response therapy [corrected].

Adult↗
PubMed1992

[Dihydropyrimidine dehydrogenase activity in lymphocytes: predictive factor for 5-fluorouracil clearance].

We previously have shown that pharmacokinetic monitoring of 5-fluorouracil (5-FU) could significantly improve the 5-FU therapeutic index when given in continuous venous infusion (Br J Cancer 59, 287-290, 1989). However, the more rational approach would be to find individual biological factors which could predict 5-FU clearance. Dihydropyrimidine dehydrogenase (DPD) is the initial enzyme in the catabolism of 5-FU. DPD activity was measured in 57 head and neck cancer patients receiving CDDP (100 mg/m2, day 1) plus 5-FU (1 g/m2/day x 5, day 2-day 6). DPD activity was measured in lymphocytes using a radioenzymatic assay (2.5 mM MgCl2, 250 microM NADPH, 20 microM 14C-5-FU) with separation of 14C-5-FU from 14C-5-FUH2 by HPLC coupled with a radiodetector. The average DPD activity measured in lymphocytes was 0.186 +/- 0.068 nmol/min/mg protein (range 0.058-0.357) and the average 5-FU clearance (Cl) was 2,523 +/- 684 ml/min/m2 (range 1,052-4,029). A significant linear correlation was demonstrated between DPD activity and 5-FU clearance (Cl = 1,099 + 7,580 DPD, r2 = 0.613, P < 0.0001). In patients evaluated for more than one cycle (n = 18), variations in 5-FU clearance were associated with corresponding variations in DPD activity. The individual determination of DPD activity measured in lymphocytes could be useful for identifying patients at risk for altered 5-FU pharmacokinetics and could be used to adjust the optimal 5-FU dose for each patient before starting the treatment.

Adult↗
PubMed1992

[Cytotoxic effects of the combination of a new nitrosourea, fotemustine, combined with 5-fluorouracil and folinic acid depend on the sequence of their administration].

The present study was designed to analyse the cytotoxic effects of the combination of fotemustine plus 5-fluorouracil (5-FU) and folinic acid (FA). Two human tumor cell lines were used; one line was derived from colon cancer (WIDR) and the other from a non-small cell lung cancer (CAL 12). Cytotoxic effects were assessed by the MTT semi-automated test in 96-well incubation plates. The effects of various drug combinations were evaluated by the isobologram method. The drug combinations tested included fotemustine concentrations of 20, 30, 40, 50 and 70 micrograms/ml, 5-FU concentrations of 5, 15 and 30 micrograms/ml, and a constant FA concentration of 10(-5) M. A total of 180 different experimental conditions were tested. When cells were exposed to fotemustine before 5-FU the final cytotoxic effects for both cell lines were additive or synergistic in the majority of cases (P less than 0.001). The 5-FU concentration was a determinant factor affecting modification of the effects of the drug combination from antagonism (with low 5-FU concentrations) to synergism (high 5-FU concentrations) (P less than 0.001). Addition of FA (10(-5) M) resulted in a significant shift towards synergistic associations for both cell lines. Administration of 5-FU before fotemustine caused a marked antagonism which 10(-5) M FA was unable to significantly shift towards simple additivity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Improved bioavailability of a new oral preparation of medroxyprogesterone acetate.

Medroxyprogesterone acetate (MPA) is widely used in the hormonal therapy of breast cancer. So far, oral formulations of MPA commercially available present a very low bioavailability, with a less than 10% extent of oral absorption. A new oral preparation of MPA has been recently developed. Based on a pilot study, an open, randomized, crossover trial has been performed on 22 breast and endometrial cancer patients to evaluate the relative bioavailability of this new oral formulation (200-mg sachet, twice daily) as compared with a standard formulation (Farlutal, 500-mg tablet, twice daily). The bioavailability evaluation was mainly based on the area under the curve measured between two administrations at steady state, after 15 days of continuous therapy. Wide interpatient variability of MPA plasma levels after oral MPA administration was confirmed. The MPA plasma levels were higher in patients treated with the new formulation than in patients treated with Farlutal. The relative bioavailability of the new preparation was 3.5 times higher than that of the standard. This new formulation represents a great improvement in the extent of oral absorption of MPA and could lead to better management of hormone-responsive tumors by hormonal therapy.

Administration, Oral↗
PubMed1991

Sequence-dependent cytotoxic effects of the combination of a new nitrosourea, fotemustine, with 5-fluorouracil plus folinic acid.

The present study was designed to analyse the cytotoxic effects of the combination of fotemustine with 5-fluorouracil (5-FU) plus folinic acid (FA). Two human tumor cell lines were used; one line was derived from colon cancer (WIDR) and the other, from a non-small-cell lung cancer (CAL 12). Cytotoxic effects were assessed using the MTT (tetrazolium bromide) semi-automated test in 96-well incubation plates. The effects of various drug combinations were evaluated by the isobologram method. The drug combinations tested included fotemustine concentrations of 20, 30, 40, 50 and 70 micrograms/ml, 5-FU concentrations of 5, 15 and 30 micrograms/ml, and a constant FA concentration of 10(-5) M. A total of 180 different experimental conditions were tested. When cells were exposed to fotemustine prior to treatment with 5-FU, the final cytotoxic effects on both cell lines were additive or synergistic in the majority of cases (P less than 0.001). The 5-FU concentration was a determinant factor that modified the effects of the drug combination from antagonism (at low 5-FU concentrations) to synergism (high 5-FU concentrations; P less than 0.001). The addition of FA (10(-5) M) resulted in a significant shift towards synergistic associations in both cell lines. Administration of 5-FU prior to treatment with fotemustine caused marked antagonism, which 10(-5) M FA could not significantly shift towards simple additivity.

Antineoplastic Agents↗