Extracellular ATP hydrolysis in Caco-2 human intestinal cell line.

Extracellular nucleotides and nucleosides activate signaling pathways that play major roles in the physiology and pathophysiology of the gastrointestinal tract. Ectonucleotidases hydrolyze extracellular nucleotides and thus regulate ligand exposure to purinergic receptors. In this study, we investigated the expression, localization and activities of ectonucleotidases using Caco-2 cells, a model of human intestinal epithelial cells. In addition, by studying ATP release and the rates of extracellular ATP (eATP) hydrolysis, we analyzed the contribution of these processes to the regulation of eATP in these cells. Results show that Caco-2 cells regulate the metabolism of eATP and by-products by ecto-nucleoside triphosphate diphosphohydrolase-1 and -2, a neutral ecto-phosphatase and ecto-5'-nucleotidase. All these ectoenzymes were kinetically characterized using intact cells, and their presence confirmed by denatured and native gels, western blot and cytoimmunofluorescence techniques. In addition, regulation of eATP was studied by monitoring the dynamic balance between intracellular ATP release and ectoATPase activity. Following mechanical and hypotonic stimuli, Caco-2 cells triggered a strong but transient release of intracellular ATP, with almost no energy cost, leading to a steep increase of eATP concentration, which was later reduced by ectoATPase activity. A data-driven algorithm allowed quantifying and predicting the rates of ATP release and ATP consumption contributing to the dynamic accumulation of ATP at the cell surface.

Natural flavonoids inhibit the plasma membrane Ca2+-ATPase.

Research on flavonoids from plant sources has recently sparked increasing interest because of their beneficial health properties. Different studies have shown that flavonoids change the intracellular Ca2+ homeostasis linked to alterations in the function of mitochondria, Ca2+ channels and Ca2+ pumps. These findings hint at plasma membrane Ca2+-ATPase (PMCA) involvement, as it transports Ca2+ actively to the extracellular medium coupled to ATP hydrolysis, thus maintaining ion cellular homeostasis. The present study aims to investigate the effect of several natural flavonoids on PMCA both in isolated protein systems and in living cells, and to establish the relationship between flavonoid structure and inhibitory activity on PMCA. Our results show that natural flavonoids inhibited purified and membranous PMCA with different effectiveness: quercetin and gossypin were the most potent and their inhibition mechanisms seem to be different, as quercetin does not prevent ATP binding whereas gossypin does. Moreover, PMCA activity was inhibited in human embryonic kidney cells which transiently overexpress PMCA, suggesting that the effects observed on isolated systems could occur in a complex structure like a living cell. In conclusion, this work reveals a novel molecular mechanism through which flavonoids inhibit PMCA, which leads to Ca2+ homeostasis and signaling alterations in the cell.

Regulation of extracellular ATP of human erythrocytes treated with α-hemolysin. Effects of cell volume, morphology, rheology and hemolysis.

Alpha-hemolysin (HlyA) of uropathogenic strains of Escherichia coli irreversibly binds to human erythrocytes (RBCs) and triggers activation of ATP release and metabolic changes ultimately leading to hemolysis. We studied the regulation of extracellular ATP (ATPe) of RBCs exposed to HlyA. Luminometry was used to assess ATP release and ATPe hydrolysis, whereas changes in cell volume and morphology were determined by electrical impedance, ektacytometry and aggregometry. Exposure of RBCs to HlyA induced a strong increase of [ATPe] (3-36-fold) and hemolysis (1-44-fold), partially compensated by [ATPe] hydrolysis by ectoATPases and intracellular ATPases released by dead cells. Carbenoxolone, a pannexin 1 inhibitor, partially inhibited ATP release (43-67%). The un-acylated toxin ProHlyA and the deletion analog HlyA∆914-936 were unable to induce ATP release or hemolysis. For HlyA treated RBCs, a data driven mathematical model showed that simultaneous lytic and non-lytic release mainly governed ATPe kinetics, while ATPe hydrolysis became important after prolonged toxin exposure. HlyA induced a 1.5-fold swelling, while blocking this swelling reduced ATP release by 77%. Blocking ATPe activation of purinergic P2X receptors reduced swelling by 60-80%. HlyA-RBCs showed an acute 1.3-2.2-fold increase of Ca2+i, increased crenation and externalization of phosphatidylserine. Perfusion of HlyA-RBCs through adhesion platforms showed strong adhesion to activated HMEC cells, followed by rapid detachment. HlyA exposed RBCs exhibited increased sphericity under osmotic stress, reduced elongation under shear stress, and very low aggregation in viscous media. Overall results showed that HlyA-RBCs displayed activated ATP release, high but weak adhesivity, low deformability and aggregability and high sphericity.

Superspin glass state in a diluted nanoparticle system stabilized by interparticle interactions mediated by an antiferromagnetic matrix.

In nanoparticle systems consisting of two magnetic materials (bi-magnetic nanoparticles or nanoparticles embedded in a magnetic matrix), there is a constantly growing interest in the investigation of the interplay between interparticle interactions and the nanoparticle-matrix interface exchange coupling, because of its enormous impact on a number of technological applications. The understanding of the mechanisms of such interplay is a great challenge, as it would allow controlling equilibrium and non-equilibrium magnetization dynamics of exchange coupled nanoparticles systems and finely tuning their anisotropy. Here, we provide evidence that this interplay leads to a collective superspin glass (SSG) behavior in a system of diluted ferromagnetic (FM) nanoparticles embedded in an antiferromagnetic (AFM) matrix (5% volume fraction of Co particles in Mn film matrix). We have developed a novel mesoscopic model to study the influence of interparticle interaction on the exchange bias (EB) and the dynamical behavior of assemblies of FM nanoparticles embedded in a granular AFM matrix. Our mesoscopic model is based on reducing the amount of simulated spins to the minimum number necessary to describe the magnetic structure of the system and introducing the adequate exchange parameters between the different spins. The model replicates remarkably well the observed static and dynamical SSG properties as well as the EB behavior. In addition, the proposed model well explains the role of the significant Co/Mn alloying and of the granularity of the matrix in mediating interparticle interactions through exchange and dipole-dipole coupling between the uncompensated moments of its grains and the exchange interaction at the Co/Mn interface.

Photoelastic sphenoscopic analysis of crystals.

Birefringent crystals are at the basis of various devices used in many fields, from high energy physics to biomedical imaging for cancer detection. Since crystals are the main elements of those devices, a great attention is paid on their quality and properties. Here, we present a methodology for the photoelastic analysis of birefringent crystals, based on a modified polariscope. Polariscopes using conoscopic observation are used to evaluate crystals residual stresses in a precise but time consuming way; in our methodology, the light beam shape, which impinges on the crystal surface, has been changed from a solid cone (conoscopy) to a wedge (sphenoscopy). Since the polarized and coherent light is focused on a line rather than on a spot, this allows a faster analysis which leads to the observation, at a glance, of a spatial distribution of stress along a line. Three samples of lead tungstate crystals have been observed using this technique, and the obtained results are compared with the conoscopic observation. The samples have been tested both in unloaded condition and in a loaded configuration induced by means of a four points bending device, which allows to induce a known stress distribution in the crystal. The obtained results confirm, in a reliable manner, the sensitivity of the methodology to the crystal structure and stress.

A photoelastic measurement system for residual stress analysis in scintillating crystals by conoscopic imaging.

The assessment of the stress state of scintillating crystals is an important issue for producers as well as users of such materials, because residual stress may arise during growth process. In this paper, a measurement system, based on the use of a photoelastic, conoscopic optical setup, is proposed for the assessment of stress state in scintillating crystals. Local stress values can be measured on the crystal in order to observe their spatial distribution. With the proposed system, it is possible to vary the dimensions of the inspected measurement volume. It has been validated with reference to a known stress state induced in a birefringent crystal sample and it has been tested for the case of loaded and unloaded samples, showing sub-millimetric spatial resolution and stress uncertainty ≤0.25 MPa. The proposed measurement system is a valid method for the inspection of scintillating crystals required by producers and users of such materials.

Role of diffusion-weighted magnetic resonance imaging in prostate cancer evaluation.

PURPOSE: The authors analysed the role of diffusion-weighted imaging (DWI) as an additional tool in magnetic resonance (MR) evaluation of prostate cancer. MATERIALS AND METHODS: Forty-one patients with suspected prostate cancer underwent MR imaging (1.5 Tesla). A DWI sequence was added to the standard morphological protocol, with a maximum b value of 1,000 s/mm(2). Diffusion maps were obtained, and the apparent diffusion coefficient (ADC) was calculated by drawing a region of interest (ROI) over healthy tissue and areas suspicious for malignancy. Histology was considered the gold standard. RESULTS: The areas correctly classified by MR imaging (42/51) had a low signal intensity on T2-weighted imaging and low ADC value (0.99 ± 0.15 mm(2)/s; p<0.01) compared with the healthy peripheral zone (PZ) (1.73 ± 0.27 mm(2)/s; p<0.01). Nine areas classified as suspicious for malignancy on T2-weighted sequences showed high ADC (1.44 ± 0.06 mm(2)/s; p<0.01) and were confirmed to be disease free by subsequent histological examination. The accuracy of morphofunctional MR imaging was 81.6% compared with 73.7% of the morphological analysis alone. CONCLUSIONS: The addition of DWI to the standard protocol increases the overall diagnostic performance of MR imaging in detecting prostatic cancer. Thus, DWI can help the clinician determine the most appropriate management strategy for the patient.

Superparamagnetic blocking and superspin-glass freezing in ultra small δ-(Fe(0.67)Mn(0.33))OOH particles.

The magnetic properties of ultra-small (~2 nm) δ-(Fe(0.67)Mn(0.33))OOH nanoparticles prepared by a microemulsion technique have been investigated by magnetization and ac susceptibility measurements at variable frequency. The results provide evidence of two different magnetic regimes whose onset is identified by two maxima in the zero-field-cooled susceptibility: a large one, centered at ~150 K (T(mh)), and a narrow one at ~30 K (T(ml)). The two temperatures exhibit a different frequency dependence: T(mh) follows a Vogel-Fulcher law τ = τ(0)exp[(E(a)/k(B))/(T-T(0))], indicating a blocking of weakly interacting nanoparticle moments, whereas T(ml) follows a power law τ = τ(0)(T(g)/T(mν)-T(g))(α), suggesting a collective freezing of nanoparticle moments (superspin-glass state). This picture is coherent with the field dependence of T(ml) and T(mh) and with the temperature dependence of the coercivity, strongly increasing below 30 K.

Thermal hysteresis of Morin transition in hematite particles.

Rhombohedral shaped, single crystal hematite particles with narrow size distribution (D(TEM) = 93 +/- 2 nm) were prepared by hydrolysis of iron chloride and polymerisation in water. The results of field dependent magnetization measurements at different warming-cooling rates and ac susceptibility measurements at varying frequencies are reported and discussed. Thermal hysteresis (DeltaT(M)) associated with the Morin transition and field dependence of the Morin temperature (T(M)) are observed in warming-cooling cycles (DeltaT(M) = 25 and 13 K for H = 0.1 and 3 T, respectively) due to the first order phase transition. A frequency dependence of ac susceptibility is observed above T(M), as a result of the relaxation of the magnetic moment of hematite particles in the weak-ferromagnetic phase.

A phase II study of UFT with leucovorin administered as a twice daily schedule in the treatment of patients with metastatic colorectal cancer.

Prolonged infusions have been shown to be safer and potentially more effective than bolus regimens of 5-fluorouracil (5-FU) as treatment for metastatic colorectal cancer (mCRC). However, infusional 5-FU requires central venous access and costly infusion pumps. Oral fluoropyrimidines enable longer exposures to 5-FU with increased convenience. Tegafur-uracil (UFT) with leucovorin (LV) given thrice daily has improved safety plus comparable survival and response rates to bolus 5-FU/LV. We conducted a phase II clinical study in 98 patients with mCRC to evaluate if UFT with LV given twice daily provided comparable time to progression (TTP), efficacy and tolerability to that reported for thrice daily in two phase III clinical studies. Secondary objectives included overall response rate (ORR) and overall survival (OS). Median TTP was 3.8 months, when compared with 3.5 months for thrice daily. The ORR (11%) and median OS (12.8 months) with twice daily administration were similar to that of thrice daily administration (12% and 12.4 months). The incidence of grade 3/4 treatment-related diarrhoea was 30% on the twice daily and 21% on the thrice daily schedule. These results suggest that twice daily administration has similar efficacy and tolerability to thrice daily administration and is an acceptable alternative for patients who would benefit from UFT with LV therapy.

Surface spin-glass freezing in interacting core-shell NiO nanoparticles.

Magnetization and AC susceptibility measurements have been performed on ∼3 nm NiO nanoparticles in powder form. The results indicate that the structure of the particles can be considered as consisting of an antiferromagnetically ordered core, with an uncompensated magnetic moment, and a magnetically disordered surface shell. The core magnetic moments block progressively with decreasing temperature, according to the distribution of their anisotropy energy barriers, as shown by a broad maximum of the low field zero-field-cooled magnetization (M(ZFC)) and in the in-phase component χ' of the AC susceptibility, centred at ∼70 K. On the other hand, surface spins thermally fluctuate and freeze in a disordered spin-glass-like state at much lower temperature, as shown by a peak in M(ZFC) (at 17 K, for H = 50 Oe) and in χ'. The temperature of the high temperature χ' peak changes with frequency according to the Arrhenius law; instead, for the low temperature maximum a power law dependence of the relaxation time was found, τ = τ(0)(T(g)/(T(ν)-T(g)))(α), where α = 8, like in spin glasses, τ(0) = 10(-12) s and T(g) = 15.9 K. The low temperature surface spin freezing is accompanied by a strong enhancement of magnetic anisotropy, as shown by the rapid increase of coercivity and high field susceptibility. Monte Carlo simulations for core/shell antiferromagnetic particles, with an antiferromagnetic core and a disordered shell, reproduce the qualitative behaviour of the temperature dependence of the coercivity. Interparticle interactions lead to a shift to a high temperature of the distribution of the core moment blocking temperature and to a reduction of magnetization dynamics.

Efficacy of an educational program on dialysis, renal transplantation, and organ donation on the opinions of high school students: a randomized controlled trial.

AIM: Organ shortage is a rate-limiting factor for transplantation. The aim of this study was to evaluate the impact of an educational program targeted to high school students on opinions concerning organ donation. METHODS: Sixteen public high schools in Torino, Italy, were randomized (2001 to 2002) as interventions (n = 8) or controls (n = 8). Intervention was composed of first questionnaire, first lesson (one to two classes; 2 hours, by a trained nephrology fellow); second lesson (all classes together; coordinated by a nephrologist, with patients and trainees); second questionnaire. Control included questionnaires. Statistical analysis compared the opinions in the questionnaires after stratification for age, sex, and type of school. RESULTS: Fourteen schools completed the program (seven interventions: 937 first and 808 second questionnaires; controls: 739 and 659). Television (82.5%) and newspapers (43.2%) were the main sources of information; knowledge on renal transplantation (grafts feasible per patient, average duration) was low; only 12.2% of the students gave correct answers. The opinions on living donation were highly positive (76.8%) with no difference in control, intervention schools, first and second questionnaires, according to sex, age, or type of school. The opinions on cadaveric transplantation were affected by the educational intervention with a drop in negative answers (from 33.7% to 16%), with an increase in positive (from 31.5% to 42.9%) and in uncertain ones (from 34.8% to 41.1%) among the intervention schools; 98% of the students appreciated the program. CONCLUSION: The positive effect on student opinions suggests the need to develop educational approaches as a part of our routine clinical work.

How many organs should one patient receive? The ethics of transplantation in the medical school.

BACKGROUND: Interest in the humanities in the medical school is growing; while several medical schools, mainly of Anglo-Saxon background, have developed dedicated courses, the experience in Italy is limited. METHODS: Since the academic year 2000 to 2001, a discussion of ethical problems was implemented in the nephrology course (fourth year of the Medical School of Torino, Italy; overall 6 years). In 2002 to 2003, a case entitled "Retransplantation of Multiple Organs (Prog Transplant 2002)" was discussed in 2 hours of small-group tutorial teaching: a boy received a renal graft at age 5, failed at age 7 due to recurrent glomerulonephritis, required a heart-kidney graft at age 11, and a second heart-kidney graft at 17. Student opinions were gathered by anonymous semistructured questionnaires at the beginning of the lessons as a basis for discussion. RESULTS: Following the lessons all students returned the questionnaires (n = 104). In the absence of competition for allocation, retransplantation was approved by 76.2%, unacceptable for 1% (22.9% uncertain-blank). With a waiting list of 10 patients, the opinions changed: 32.4% approved transplantation, 6.7% didn't approve it, 60.9% were uncertain. A theoretical categorization into deontological or utilitaristic approaches favored the first (41.9% vs 26.7%), with a high prevalence of blank-uncertain (31.5%); 21.9% of the students would change their opinion was that study head of the Transplant Department. CONCLUSION: Ethical aspects of the medical profession have been discussed with interest by medical school students; the high prevalence of uncertain answers and requests to develop specific tools underline the importance of this educational approach.

Kidney vending: opinions of the medical school students on this controversial issue.

BACKGROUND: In this era of globalization, in which different cultural and economic barriers are progressively abated, in the context of the development of rapid information networks such as the Internet, physicians are increasingly challenged by clinical and ethical questions. Kidney vending, banned in some countries, legal or tolerated in others, may be the prototype of the ethical aspects of health-care globalization. METHODS: To test the interest and the opinions of medical school students, a simulated case was proposed to students attending a seminar within the nephrology course fourth year of the Medical School of Torino, san Luigi): an Italian patient comes to the nephrologist's office asking for advice on the possibility to legally buy a kidney in a foreign country. The 43 students attending the lesson answered a semistructured questionnaire (15 boys, 28 girls, of median age 23 years). Attendance was within the usual standards (50 students inscribed per year). From the clinical point of view, 11.6% were favorable to kidney vending, 51.2% were contrary, 37.2% were uncertain. From the ethical point of view, no student was pro, 81.4% were contrary, and 18.6% were uncertain. The open comments underline the importance of patient self-determination and of informed consent. Similar opinions were recorded in a nonstructured question: "What should physician's attitude be, in the face of a choice he/she doesn't share?" CONCLUSION: Students' uncertainties and doubts underline the need to discuss ethical scenarios in the clinical teachings of the medical school.

To give or to receive? Opinions of teenagers on kidney donation.

BACKGROUND: The attitude toward living donation varies widely in the world, for economic and cultural reasons. In Italy, as in other Mediterranean settings, the role of living kidney donation is minor. AIM: To analyze the reasons for this attitude, we gathered data in a general population sample of high school students in a large northern Italian industrial city (Torino, about 900,000 inhabitants). METHODS: Semistructured questionnaires (n = 1676), gathered in 2001 to 2002 in 14 high schools, in the context of an educational program on dialysis, renal transplantation, and organ donation, were analyzed presumably reflecting opinions gathered before the educational intervention. RESULTS: Most students, in the case of a close relative or partner needing dialysis, answer that they would donate a kidney (yes: 78.2%, no: 2.9%, uncertain-blank: 18.9%); receiving a living donor kidney is felt as disturbing: only 57.5% of the students would accept it (no: 5.9%, uncertain-blank: 36.6%), mainly because of fear of long-term problems for the donor. Donation from an older to a younger person is seen more positively than vice versa. CONCLUSION: In our settings, the attitude of the teenagers on living donation is positive; however, while "giving" is positively seen, the presence of unresolved fears is witnessed by the lower acceptance of the idea of "taking." These data suggest to focus on the risks of kidney donation in educational campaigns and in patient-physician information. The positive attitude shared by the teenagers supports the working hypothesis that lack of information is one of the determinants of the low living donor transplantation rate in our area.

Unexpected absence of correlation between the genetic mechanisms regulating beta-carboline-induced seizures and anxiety manifested in an elevated plus-maze test.

Among the ligands of the benzodiazepine site, one can mention the benzodiazepines as agonists and some beta-carbolines (e.g. methyl-beta-carboline-3-carboxylate, abbreviated hereafter beta-CCM) as inverse agonists. Most benzodiazepines and beta-carbolines act on processes involved in memory, anxiety, and convulsions with opposite physiological effects. Since these molecules have influences on both anxiety and convulsions, we predicted that there would exist a genetic correlation between anxiety evaluated in an elevated plus-maze and susceptibility to beta-CCM-induced seizures. Using inbred strains of mice, the genetic correlation was estimated with the Hegmann and Possidente model. An absence of genetic correlation was found, showing that the mechanisms responsible for basal anxiety measured with the elevated plus-maze test and those leading to susceptibility to beta-CCM-induced seizures do not share the same genetic pathways.

Paclitaxel and carboplatin adjuvant therapy alone or with radiotherapy for resected nonsmall cell lung carcinoma: a feasibility study of the Minnie Pearl Cancer Research Network.

BACKGROUND: The objective of this study was to determine the feasibility and toxicity of paclitaxel and carboplatin given in the adjuvant setting alone for patients with resected Stage IB disease and combined with radiotherapy for patients with resected Stages II and IIIA disease and selected patients with Stage IIIB and IV disease (Revised International System for Staging of Lung Cancer). METHODS: One hundred two patients with resected nonsmall cell lung carcinoma were treated in the postoperative period with 3 courses of paclitaxel 200 mg/m(2) intravenously (i.v.) over 1 hour and carboplatin area under the curve of 6 i.v. every 3 weeks for 3 courses. Patients with Stage IB received no further therapy, and those with higher stages also subsequently received radiotherapy plus concurrent weekly paclitaxel and carboplatin over 6 weeks. The median age was 61 years, with 56 men and 46 women, and the predominant histologic type was adenocarcinoma. Twenty pneumonectomies, 80 lobectomies, and 2 other procedures were performed. Ninety percent of the patients (92 of 102) received all 3 courses of adjuvant paclitaxel and carboplatin (84% received full doses). Seventy-three percent received full doses of radiotherapy and concurrent weekly chemotherapy (49 of 67 patients), and 14 others received greater than 75% of the radiotherapy and concurrent chemotherapy. RESULTS: Toxicity of the chemotherapy was mild with only three hospitalizations for neutropenia and fever and no treatment-related deaths. Severe hypersensitivity occurred in six patients (6%). Concurrent radiation therapy and weekly chemotherapy also was well tolerated with the exception of Grade 3-4 esophagitis observed in 27% (17 of 67 patients). Follow-up was short with a median of 10 months, and 65% of all patients remained progression free. CONCLUSIONS: Three courses of paclitaxel and carboplatin is tolerable, feasible, and can be delivered in most patients in the adjuvant setting. Subsequently, in higher stage patients, concurrent postoperative radiation therapy and weekly paclitaxel and carboplatin is well tolerated and delivered in most patients. Definitive prospective randomized Phase III adjuvant trials are warranted.

A phase I-II trial of topotecan and gemcitabine in patients with previously treated, advanced non-small cell lung cancer (LOA-3).

The purposes of this study were to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), toxicity profile, and antitumor activity of topotecan (TOP) and gemcitabine (GEM) combination therapy when administered to patients with previously treated, advanced, non-small cell lung cancer. Both compounds were administered intravenously over 30 min, with TOP on days 1-5 and GEM on days 1 and 5 only. Nineteen patients were treated with 75 courses at three dose levels. The MTD was 0.75 and 400 mg/m2 for TOP and GEM, respectively, with thrombocytopenia and neutropenia as the DLTs. Partial responses were achieved in 3 of 17 patients (18%) with measurable disease. Six patients (32%) had disease stabilization for at least four courses of treatment. The median survival was 10 months from the initiation of TOP and GEM. This combination was relatively well tolerated and exhibited promising antitumor activity in patients with advanced, previously treated, non-small cell lung cancer.

Phase I dose-finding and pharmacokinetic trial of irinotecan (CPT-11) administered every two weeks.

OBJECTIVES: This trial was performed to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and pharmacokinetic profile of irinotecan (CPT-11) when administered on a once-every-2-week schedule. PATIENTS AND METHODS: CPT-11 was administered to successive cohorts of patients at progressively increasing starting doses ranging from 125 to 350 mg/m2. The MTD and DLTs were determined both for CPT-11 alone and for CPT-11 followed by filgrastim (G-CSF). Plasma samples were obtained during the first 24 hours after initial dosing to determine the total concentrations (lactone + carboxylate forms) of CPT-11; of the active metabolite SN-38; and of SN-38 glucuronide (SN-38G). RESULTS: Neutropenic fever was the DLT for CPT-11 at the 300 mg/m2 dose level. When G-CSF was added, dose escalation beyond 350 mg/m2 could not be achieved due to grade 2-3 toxicities that prevented on-time retreatment with CPT-11. Severe, late diarrhea was uncommon on this schedule. Peak plasma concentrations of SN-38 and SN-38G were approximately 2.5% and 4.2% of the corresponding peak plasma concentration for CPT-II, respectively The harmonic mean terminal half-lives for CPT-11, SN-38, and SN-38G were 7.1 hours, 13.4 hours, and 12.7 hours, respectively. No predictive correlation was observed between CPT-11 or SN-38 peak concentration or AUC and first-cycle diarrhea, neutropenia, nausea, or vomiting. Across the range of doses studied, mean CPT-11 clearance was 14.0 +/- 4.0 l/h/m2 and volume of distribution was 146 +/- 45.9 l/m2. CONCLUSIONS: When administered every two weeks, the recommended phase II starting dose of CPT-11 is 250 mg/m2 when given alone and 300 mg/m2 when supported by G-CSF. This every-two-week regimen offers a tolerable and active alternative to weekly or every-three-week single-agent CPT-11 therapy.

A phase I trial of gemcitabine and infusional 5-fluorouracil (5-FU) in patients with refractory solid tumors: Louisiana Oncology Associates protocol no. 1 (LOA-1).

The major purposes of this study were to determine the maximally tolerated dose (MTD), dose-limiting toxicity (DLT), toxicity profile, and antitumor activity of gemcitabine (GEM) (Gemzar) and 5-fluorouracil (5-FU) combination therapy when administered to patients with advanced solid tumors. GEM was administered intravenously over 30 minutes on days 1, 8, and 15, and 5-FU was administered as a continuous intravenous infusion from day 1 through day 15 of each 28-day treatment course. Seventeen patients (13 men and 4 women, median age 57, all previously treated with chemotherapy) were treated with 68 courses at 3 dose levels: 800/200, 1,000/200, and 1,000/300 [GEM (mg/m2/week)/ 5-FU (mg/m2/day)]. Two further patients were not fully evaluable for toxicity; one died from a probable pulmonary embolism, and one refused further treatment after developing grade II mucositis and dermatitis after her day 1 to 7 treatment. At the third dose level, 2 of 4 patients developed grade III mucositis; one also developed grade IV neutropenia with fever and grade III thrombocytopenia. Patient accrual then resumed at the second dose level. At this level, 10 patients were treated, with two developing grade III mucositis. One of these patients also developed grade IV dermatitis. No other patient developed grade III or IV side effects. Prophylactic dexamethasone was initiated after 4 of the first 7 patients (including 1 of the not fully evaluable patients) developed dermatitis-grade IV in 1 patient and grade II in the remaining 3 patients. After the steroids were initiated, 4 of the last 11 patients treated developed dermatitis, but grade 1 in all cases. One patient with metastatic gastric cancer achieved a near-complete response of his gastric mass and adrenal metastasis. Minor responses were achieved in a patient with colon carcinoma and a patient with an ethmoid sinus adenoid cystic carcinoma. The MTD and recommended dose for phase II clinical trials of GEM and 5-FU on the above schedule is 1,000 mg/m2 and 200 mg/m2 respectively, with mucositis as the DLT.