NMR relaxation induced by iron oxide particles: testing theoretical models.

Superparamagnetic iron oxide particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of iron oxide particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water.

Phase I - II study to assess the feasibility and activity of the triple combination of 5-fluorouracil/folinic acid, carboplatin and irinotecan (CPT-11) administered by chronomodulated infusion for the treatment of advanced colorectal cancer. Final report of the BE-1603 study.

Thirty-six metastatic colorectal cancer patients received every 2 weeks, as first- (17) or second-line (19) treatment a combined chronotherapy with CPT-11 (infused at day 1 from 2 to 8 a.m.; peak at 5 a.m.), given with 5FU (700 mg/m(2) per day; days 2-5) and folinic acid (300 mg/m(2) per day; days 2-5) both infused from 10 p.m. to 10 a.m. with a peak at 4 a.m., and carboplatin (40 mg/m(2) per day; days 2-5; infused from 10 a.m. to 10 p.m.; peak at 4 p.m.). The doses of CPT11 could be easily pushed from 120 to 180 mg/m(2) in successive cohorts in the phase I part of the study (11 cases). Twenty-five patients were then treated in the phase II of the trial. The overall toxicity was mild leading to dose-reductions in only 11-13% courses. The tumoral activity was interesting with 81% responses and 94% tumour control. Also prolonged survivals were recorded with 8.8 months of progression free and 15.6 months overall survivals. More prolonged survivals were observed in chemotherapy naive patients. Seven patients (19%) could be reoperated from their residual disease.

[Chronotherapy with 5-fluorouracil folinic acid and oxaliplatin delivered over 48 hours every second week in colorectal cancer. The CHC-Liège experience (Belgium)]. / Chronochimiothérapie à base de 5-fluorouracil, acide folinique et oxaliplatine administrée en deux jours toutes les deux semaines pour le cancer colorectal. L'expérience du CHC-Liège (Belgique).

One hundred and ten consecutive patients suffering from a colorectal cancer received chronotherapy infused over two days every two weeks. Each course comported 5 FU 3g/m(2), folinic acid (600 mg/m(2) - l. form or 1200 mg/m(2)--racemic form) and oxaliplatin (85/mg/m(2)--adjuvant indication or 100mg/m(2)--palliative indication). According to chronobiological concepts, 5 FU and folinic acid were infused from 10 pm to 10 am with a peak at 4 am while oxaliplatin was delivered from 10 am to 10 pm with a peak at 4 pm. The overall tolerance was excellent with a maximum of 17% patients experiencing a grade 3 toxicity. The toxicity was higher in women, in older patients (>=70) or in case of flat infusion. In adjuvant situation (60 cases), progression free and overall survivals established respectively at 76% (42+months) and 88% (45+months). Fifty-two percent response rate were recorded within the palliative group (50 cases) with an overall 68% disease control. Median progression free survival was seven months but median survival was not attained at 31+ months. Thirty percent patients could benefit from a curative surgery after chemotherapy. Older patients (>=70) experienced worsened survival. In conclusion, we think that our chrono-FOLFOX 2-12 should be proposed as standard treatment for colorectal cancer patients.

[Chemotherapy for human gastric cancer: a review]. / Qu'attendre de la chimiothérapie dans le cancer de l'estomac en 2008?

The authors review the actual position of medical treatment for human gastric cancer. Chemotherapy has been evaluated first in palliative situation, then as adjuvant post-surgical approach either through systemic or intraperitoneal route. Now chemotherapy may also be proposed as neoadjuvant (before surgery) treatment as part of an integrated global pluridisciplinary approach. New hopes to improve the prognosis come then from both neoadjuvant and adjuvant chemotherapy (+/- radiotherapy) and further from less toxic infusional therapies (chronomodulation), new schedules with proved active molecules (docetaxel, oxaliplatin, irinotecan, pemetrexed) as well as from new targeted treatments (against ie, EGF-receptor and angiogenesis).

Specific effects of ras oncogene expression on the growth and histogenesis of human epidermal keratinocytes.

Little progress has been made in identifying specific regulatory pathways that might be affected in cells by a mutationally activated p21ras when its expression does not lead to complete transformation. We wished to determine whether a normal, diploid human epithelial cell in which activation of ras had occurred could be identified in culture and, furthermore, whether expression of a mutant p21ras in such an otherwise normal cell would result in abnormal histogenic behavior in vivo. Thus, we introduced the v-Ha-ras gene into an early passage culture of normal human epidermal keratinocytes via a defective retrovirus. We examined these genetically engineered cells for changes in growth and differentiation, both in culture and in the epithelium formed when cultures were grafted to the skin of nude mice. We have found that keratinocytes expressing p21v-ras are independent of epidermal growth factor (EGF)--a factor which is normally essential for progressive colony growth, but that they are otherwise indistinguishable in culture from normal cells. v-ras keratinocytes also secrete a factor possessing some specific biological activities of members of the fibroblast growth factor (FGF) family, but which is distinct from acidic and basic FGF. In short-term dermal grafts the v-ras cells form a non-invasive and normally differentiating epidermis. However, the cells express elevated levels of keratin 19, which is a characteristic of fetal epidermis and of premalignant lesions of some stratified squamous epithelia.

Dose-response relationship of epirubicin-based first-line chemotherapy for advanced breast cancer: a prospective randomized trial.

PURPOSE: We compared prospectively the antitumor efficacy of two combination chemotherapy regimens with two different dose levels of epirubicin as first-line treatment for advanced breast cancer. PATIENTS AND METHODS: One hundred forty-one fully assessable patients were randomized to receive either our intensified schedule (group A, n = 71) of epirubicin 50 mg/m2 on days 1 and 8 (every 3 weeks), or a non-intensified program (group B, n = 70) in which epirubicin was only administered on day 1. Both groups also received fluorouracil (5 FU) and cyclophosphamide 500 mg/m2 on day 1 of each course. RESULTS: A statistically significant difference in response rate was observed (69% in group A v 41% in group B, P < .001) for both locally advanced (LA) and recurrent metastatic (RM) disease. Response duration (22 v 14 months, P < .01) and time to progression (TTP; 19 v 8 months, P < .02) were also significantly improved. Overall survival was similar in both groups. However, univariate and/or multivariate analyses showed a meaningful relationship between type of treatment allocated, dose-intensity (DI) of epirubicin, and response rate, as well as between TTP and survival. Ultimately, TTP and survival were also influenced by further treatment modalities, namely, hormonotherapy and chemotherapy. CONCLUSION: This study validates prospectively the concept of a dose-response relationship for an anthracycline-based chemotherapy in previously untreated advanced breast cancer.

Sequential administration of epirubicin and paclitaxel for advanced breast cancer. A phase I randomised trial.

Forty-six previously untreated patients with advanced breast cancer were eligible for the present randomised phase I study. It aimed to evaluate the toxicity and activity of a therapeutic sequence with epirubicin on day 1 followed by paclitaxel on day 2 (sequence A) or the reverse sequence, ie., paclitaxel on day 1 followed by epirubicin on day 2 (sequence B). The starting doses of epirubicin and paclitaxel, administered either according to sequence A or B, (level 1 cohort) were 90 mg/m2 and 175 mg/m2, respectively. Per cohort of 3 patients, the dose of paclitaxel was increased by 25 mg/m2 (levels 2 and 4) and of epirubicin by 10 mg/m2 (levels 3 and 5). Treatment was repeated with 3-week intervals. The maximal tolerated dose (MTD) was achieved at level 1 in sequence B (paclitaxel first) and level 3 (epirubicin 100 mg/m2 followed by paclitaxel 200 mg m2) in sequence A. Dose limiting toxicity (DLT) was neutropenia (+/- febrile) in both sequences. Cardiac events occurred in 28% of the patients; significant decrease in left ventricular ejection function (LVEF) was observed in 8/33 and in 2/13 patients in sequence A and B, respectively. This was associated with 5 and 1 cardiac heart failure (CHF), respectively. In 43 evaluable patients, 10 CR and 25 PR were observed (overall response rate 81%). In the 20 patients with locally advanced disease (LABC), the respective numbers were 7 CR and 11 PR; in the 23 metastatic (MBC) patients, 3 CR and 14 PR were recorded. The median survival of the both groups was not reached at 33 + months. In conclusion , the combination of epirubicin and paclitaxel has significant activity in breast cancer. The recommended sequence of both drugs in combination therapy, mainly to avoid neutropenia, is epirubicin day 1 followed by paclitaxel on day 2. Cardiac toxicity remains problematic in either sequence of administration.

Theoretical and experimental study of ON-Resonance Saturation, an MRI sequence for positive contrast with superparamagnetic nanoparticles.

Superparamagnetic iron oxide nanoparticles (SPM particles) are widely used in MRI as negative contrast agents. Their detection is sometimes difficult because negative contrast can be caused by different artifacts. To overcome this problem, MRI protocols achieving positive contrast specific to SPM particles were developed such as the ON-Resonance Saturation (ONRS) sequence. The aim of the present work is to achieve a bottom-up study of the ONRS sequence by an understanding of the physical mechanisms leading to positive contrast. A complete theoretical modeling, a novel numerical simulation approach and experiments on agarose gel phantoms on a 11.7 T MRI system were carried out for this purpose. The influence of the particle properties and concentration - as well as the effect of the sequence parameters on the contrast - were investigated. It was observed that theory and experiments were in strong agreement. The tools developed in this work allowed to predict the parameters leading to the maximum contrast. For example, particles presenting a low transverse relaxivity can provide an interesting positive contrast after optimization of their concentration in the sample.

Bottom-up study of the MRI positive contrast created by the Off-Resonance Saturation sequence.

Superparamagnetic iron oxide nanoparticles (SPM particles) are used in MRI to highlight regions such as tumors through negative contrast. Unfortunately, sources as air bubbles or tissues interfaces also lead to negative contrast, which complicates the image interpretation. New MRI sequences creating positive contrast in the particle surrounding, such as the Off-Resonance Saturation sequence (ORS), have thus been developed. However, a theoretical study of the ORS sequence is still lacking, which hampers the optimization of this sequence. For this reason, this work provides a self-consistent analytical expression able to predict the dependence of the contrast on the sequence parameters and the SPM particles properties. This expression was validated by numerical simulations and experiments on agarose gel phantoms on a 11.7 T scanner system. It provides a fundamental understanding of the mechanisms leading to positive contrast, which could allow the improvement of the sequence for future in vivo applications. The influence of the SPM particle relaxivities, the SPM particle concentration, the echo time and the saturation pulse parameters on the contrast were investigated. The best contrast was achieved with SPM particles possessing the smallest transverse relaxivity, an optimal particle concentration and for low echo times.

HIV DNA and antibodies in syringes from injecting drug users: a comparison of detection techniques.

OBJECTIVE: Direct HIV testing of individual injecting drug users is not always feasible. As an alternative, we have evaluated the sensitivity and specificity of several techniques for detecting HIV-1-specific products in used syringes. DESIGN: Polymerase chain reaction (PCR) and antibody-capture assays were compared using syringes prepared with blood from HIV-1-positive and -negative individuals. METHODS: PCR sensitivity was maximized, enabling detection of single copies of HIV-1-specific proviral DNA. The limits of detection from used syringes were determined for PCR by diluting extracts and correlated to CD4+ cell counts. Similarly, limits of detection were determined for enzyme immunoassays (EIA) and Western blot. RESULTS: All techniques were highly specific, although with PCR false-positives were detected occasionally. EIA proved more sensitive than Western blot in detecting needles containing HIV-1-infected individuals' blood. Even after prolonged storage of syringes at room temperature, EIA was equal to or better than PCR as an HIV-1 detection technique. The most sensitive method for detecting HIV-1 was the viral-based EIA when the recommended predilution step was omitted. CONCLUSIONS: EIA proved preferable to PCR because of their higher sensitivity, absence of false-positives and easier sample preparation and analysis.

Poor sensitivity, specificity, and reproducibility of detection of HIV-1 DNA in serum by polymerase chain reaction. The Transfusion Safety Study Group.

A series of recent studies have reported detection by the polymerase chain reaction (PCR) of cell-free human immunodeficiency virus type 1 (HIV-1) DNA (as opposed to virion RNA) in serum from both seropositive and seronegative persons. To evaluate the sensitivity, specificity, and reproducibility of PCR detection of cell-free HIV-1 DNA, we distributed coded panels containing 98 serum specimens obtained from well-characterized, infected individuals and control blood donors to the two laboratories with reported experience with this technique. Positive results were reported with HIV-1 gag primers (SK38/39) for 48 of 188 separate PCR determinations on DNA extracts from 44 serum samples from seropositive patients (25.5% sensitivity). HIV-1 gag signal was also reported for 28 of 151 PCR determinations on 34 samples from noninfected blood donors (18.5% false-positive rate). PCR for HIV-1 env DNA performed in one laboratory was negative on all specimens from seropositive and seronegative patients. Results for cell-free HIV-1 gag and human genomic (beta-globin or HLA DQ-alpha) DNA were inconsistent on replicate and serial specimens evaluated within each laboratory and between laboratories. These results indicate that current techniques for detecting cell-free HIV-1 DNA in serum lack adequate sensitivity, specificity, and reproducibility for widespread clinical applications.

Chronotherapy with 5-fluorouracil, folinic acid and carboplatin for metastatic colorectal cancer; an interesting therapeutic index in a phase II trial.

The aim of this study was to develop a phase II study gauging the contribution of a daily low-dose of carboplatin combined with 5-fluorouracil (5-FU) and folinic acid (FOL) in a chronotherapy schedule for advanced colorectal cancer patients. 60 patients with metastatic colorectal cancer were included in a phase II trial in which 50% of patients had received prior chemotherapy of up to three regimens. Treatment consisted of a combination of 5-FU (700 mg/m(2)/day) and FOL (300 mg/m(2)/day) infused from 10.00 pm to 10. 00 am peaking at 4.00 am with carboplatin infused from 10.00 am to 10.00 pm at 40 mg/m(2)/day with a peak at 4.00 pm. 4-day courses were repeated every 2 weeks in an ambulatory setting with a programmable pump. Patients experienced excellent tolerance (grades III-IV%): diarrhoea, 8.1; nausea/vomiting, 4.8; mucositis, 3.2; skin or neurological 1.7; granulocytes 29.0; platelets and haemoglobin (Hb) 9.7. Major tumour responses were observed in 47% of cases, 4 complete response (CR), 24 partial response (PR); 3 CR and 6 PR (69%) were recorded in 13 previously untreated patients; 11 (18%) underwent subsequent surgical resection of residual metastases. Median survival was 14.6 months with 22% patients surviving over 2 years (35% survival for responders versus 0 for non-responders). In conclusion, this chronotherapy determined administration of 5-FU/FOL and carboplatin yielded an excellent therapeutic index for the combination and warrants further evaluation in the first-line treatment of metastatic colorectal cancer.

A sensitive viral capture assay for detection of plasma viremia in HIV-infected individuals.

Human immunodeficiency virus was detected in the serum/plasma of individuals infected with human immunodeficiency virus (HIV) after capture of virions on microparticles coated with monoclonal antibodies to external and transmembrane proteins of HIV-1. We analyzed serial samples obtained from 6 individuals who seroconverted, 18 asymptomatic, and 12 AIDS patients. HIV-1 RNA was detected in all (29/29) seropositive samples and in 6 seronegative samples immediately preceding seroconversion. In contrast, HIV antigen was detected in 13/29 (45%) of seropositive samples. HIV-1 RNA was also detected in 3 antigen-negative samples from one individual 8-5 months prior to seroconversion and in one sample from another person 2 days before antigen positivity. The intensity of the polymerase chain reaction (PCR) signal paralleled the concentration of HIV antigen. Conversely, seropositive HIV antigen-negative samples gave a weaker PCR signal. HIV-1 RNA was detected in 10/18 (60%) samples from asymptomatic, HIV antigen-negative, individuals and in 11/12 (92%) specimens obtained from AIDS patients. The viral capture method may provide a sensitive, specific, and semiquantitative means of detecting circulating HIV at all stages of infection.

Selectivity of human T lymphotropic virus type-1 (HTLV-1) and HTLV-2 infection among different populations in Brazil.

A seroprevalence study for human T lymphotropic virus type-1 (HTLV-1) and HTLV-2 was conducted in Sao Paulo, Brazil among 2,312 individuals that included following groups: 1,148 volunteer blood donors, 37 patients with tropical spastic paraparesis (TSP), 53 with lymphoproliferative disorders, 171 with a history of multiple blood transfusions, 268 human immunodeficiency virus type-1 (HIV-1) seropositive subjects, and 635 Amazonian Indians. Antibodies to HTLV-1/2 were screened by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blot and/or radioimmunoprecipitation. The differentiation of HTLV-1 and HTLV-2 was achieved using a synthetic recombinant peptide (rgp46) ELISA. We confirmed the presence of HTLV-1 infection in Brazil, both in blood donors (0.4%) and in patients exposed to blood transfusions (2.9%), as well as the occurrence of HTLV-1-associated TSP (11 patients, or 30% of all TSP cases) and adult T cell leukemia/lymphoma (two cases, or 3.5% of all hematologic malignancies). The HIV-1 infected individuals were shown to be coinfected (8.9%) with either HTLV-1 or HTLV-2. All HIV-1 and HTLV-2 coinfected individuals were intravenous drug abusers. In addition, we also demonstrated the presence of HTLV-2 (4.7%), and HTLV-1/2 (0.8%) in tribes of Amazonian Indians who lived in the eastern Amazon basin (southeastern State of Para). The selectivity of these retroviral infections in particular groups is emphasized, as well as the need for HTLV-1/2 screening of all blood donors in Brazil as a public health measure.

Phase II trial with high-dose ifosfamide and mesna given in a 24-h infusion for advanced GI tract cancer.

In all, 26 patients with advanced GI tract cancer (among whom 23 had liver metastases) were treated in a phase II trial with a 24-h infusion of high-dose ifosfamide and mesna (5 g/m2). Two PR, 1 CR and 4 NC were evidenced among 23 patients evaluable for response. The toxicity was significant and mainly expressed in the hair, digestive tract, granulocytes and CNS. One patient died from CNS and kidney toxicities. Only patients with good clinical indices, normal serum albumin and creatinine levels and without pelvic involvement seemed to be candidates to benefit from the treatment.

Cancer-associated alteration of circadian rhythms in carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) in humans.

A circadian rhythm of serum concentrations of two tumor markers (CEA and AFP) was demonstrated in individuals not suffering from cancer. These rhythms exhibited a diurnal peak with a nocturnal dip. They disappeared in cancer groups. However, in some cancer subjects, a circadian activity was still detectable, but with quite different characteristics (time of peak, amplitude) of rhythms when compared to controls. The importance of such findings is discussed with regard to the circadian kinetics of cancer cells, to time scheduled cancer treatments and to the detection of cancer.

Importance of 5-fluorouracil dose-intensity in a double randomised trial on adjuvant portal and systemic chemotherapy for Dukes B2 and C colorectal cancer.

366 patients fully resected from a Dukes B2 or C colorectal cancer were randomised to receive 6 courses of systemic chemotherapy comprising either 5-fluorouracil (5 FU) alone (arm A: 450 mg/m2/day-5/21 days) or combined folinic acid (FOL) and 5 FU (arm B: respectively 200 mg/m2 racemic form or 100 mg/m2-l-form and 370 mg/m2/day-5/21 days). 173 patients had also been initially randomised to receive one course of intraportal chemotherapy just after surgery or no portal treatment. Oral levamisole (150 mg/day; 3 days every other week) was given to all patients for one year. A significantly higher incidence of leuco-granulocytopenia was observed in the arm A (5 FU alone) inducing more frequent dose delays and adaptations as well as levamisole's withdrawal. Then dose-intensities and dose-intensity products were lower in this arm but the dose intensity expressed in mg/m2/week remained higher (631 +/- 107 vs 557 +/- 99; p < 0.001). The median follow-up in the study was 4.5 years. Relapse free (RFS) and overall survivals (OAS) were prolonged in the 5 FU alone group peculiarly in those patients who had not been randomised for portal treatment. Curves diverged progressively with longer follows-up (at 8 years; RFS in arm A: 67-71% vs 59-53% in arm B; OAS in arm A: 72-74% vs 56-46% in arm B). Patients suffering from a colon or a Dukes C cancer benefited the most from the treatment with 5 FU alone. The results are discussed in the light of other recent adjuvant trials. Well dosed 5 FU over a short period of time without folinic acid may be a valuable and inexpensive adjuvant treatment for colorectal cancer. Levamisole may no longer be recommended in this setting.

Ambulatory chrono-chemotherapy by portable pumps: feasibility and compliance. Nursing aspects.

A study was undertaken among thirty seven advanced cancer patients, receiving chronochemotherapy by ambulatory programmable-in-time pumps. Drugs were infused through simple or double chamber venous, and/or arterial totally implantable side-ports. The aim was to evaluate the treatment feasibility in an ambulatory mode, while appreciating the patient's physical and psychological tolerance and measuring the treatment's impact on the patient's daily life and family unit. The results of the study showed that, out of a total of 1613 days of treatment, only 27 returns to the hospital were required, which were due to minor incidents (mainly pipe leaks). No treatment was abandoned or interrupted by non-compliance and all patients maintained the ambulatory mode of treatment. Moreover patients cooperated fully with this mode of treatment with firm support from their relatives. The study emphasized the necessity of proper training for patients and good information about the delivery system, as a means of preventing the poor functioning of equipment and the ability to take promp action in order to maintain life functions and to confront potential side effects.

[Chronopharmacologic approach to the administration of anticancer agents in pancreatic adenocarcinoma. Pilot experience]. / Approche chronopharmacologique de l'administration des agents anticancéreux dans l'adénocarcinome pancréatique. Expérience pilote.

The authors first analyzed the potential interest of the delivery of anticancer agents according to chronobiological concepts for human pancreatic cancer. They report their experience on 41 patients treated in adjuvant (12 cases) or palliative (29 cases) situations. The excellent therapeutic index observed warrants further evaluations of this concept in randomized trials.