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Biomedical subjects

D Caron

Publications and source records attributed to D Caron.

At least 19 recordsLinked to original sources
PubMed2000

Preoperative mobilization of circulating dendritic cells by Flt3 ligand administration to patients with metastatic colon cancer.

PURPOSE: To evaluate preoperative dendritic cell (DC) mobilization and tumor infiltration after administration of Flt3 ligand (Flt3L) to patients with metastatic colon cancer. PATIENTS AND METHODS: Twelve patients with colon cancer metastatic to the liver or lung received Flt3L (20 microg/kg/d subcutaneously for 14 days for one to three cycles at monthly intervals) before attempted metastasectomy. The number and phenotype of DCs mobilized into peripheral-blood mononuclear cells (PBMCs) were evaluated by flow cytometry. After surgical resection, metastatic tumor tissue was evaluated for DC infiltration. In vivo immune responses to recall antigens were measured. RESULTS: After Flt3L administration, on average, the total number of leukocytes in the peripheral blood increased from 5.9 +/- 1.0 x 10(3)/mm(3) to 11.2 +/- 3.8 x 10(3)/mm(3) (mean +/- SD, P: =. 0001). The percentage of CD11c(+)CD14(-) DCs in PBMCs increased from 2.4% +/- 1.8% to 8.8% +/- 4.7% (P: =.004). Delayed-type hypersensitivity (DTH) responses to recall antigens (CANDIDA:, mumps, and tetanus) showed marginally significant increases in reactivity after Flt3L administration (P: =.06, P: =.03, and P: =.08, respectively). An increase in the number of DCs was observed at the periphery of the tumors of patients who received Flt3L compared with those of patients who had not. CONCLUSION: Flt3L is capable of mobilizing DCs into the peripheral blood of patients with metastatic colon cancer and may be associated with increases in DC infiltration in the peritumoral regions. Flt3L mobilization is associated with a trend toward increased DTH responses to recall antigens in vivo. The use of Flt3L to increase circulating DCs for cancer immunotherapy should be considered.

Adjuvants, Immunologic↗
PubMed2000

In vivo generation of human dendritic cell subsets by Flt3 ligand.

Dendritic cells (DCs) represent a family of ontogenically distinct leukocytes involved in immune response regulation. The ability of DCs to stimulate T-cell immunity has led to their use as vectors for immunotherapy vaccines. However, it is unclear whether and to what degree in vitro-generated DCs are representative of DCs that develop in vivo. Treatment of mice with human Flt3 ligand (FL) dramatically increases the number of DCs. We report here that administration of FL to healthy human volunteers increased the number of circulating CD11c(+ )IL-3Ralpha(low) DC (mean 44-fold) and CD11c(-) IL-3Ralpha(high) DC precursors (mean 12-fold). Moreover, the CD11c(+ )DCs were efficient stimulators of T cells in vitro. Thus, FL can expand the number of circulating, functionally competent human DCs in vivo.

Adjuvants, Immunologic↗
PubMed2000

Flt3-ligand and granulocyte colony-stimulating factor mobilize distinct human dendritic cell subsets in vivo.

Dendritic cells (DCs) have a unique ability to stimulate naive T cells. Recent evidence suggests that distinct DC subsets direct different classes of immune responses in vitro and in vivo. In humans, the monocyte-derived CD11c+ DCs induce T cells to produce Th1 cytokines in vitro, whereas the CD11c- plasmacytoid T cell-derived DCs elicit the production of Th2 cytokines. In this paper we report that administration of either Flt3-ligand (FL) or G-CSF to healthy human volunteers dramatically increases distinct DC subsets, or DC precursors, in the blood. FL increases both the CD11c+ DC subset (48-fold) and the CD11c- IL-3R+ DC precursors (13-fold). In contrast, G-CSF only increases the CD11c- precursors (>7-fold). Freshly sorted CD11c+ but not CD11c- cells stimulate CD4+ T cells in an allogeneic MLR, whereas only the CD11c- cells can be induced to secrete high levels of IFN-alpha, in response to influenza virus. CD11c+ and CD11c- cells can mature in vitro with GM-CSF + TNF-alpha or with IL-3 + CD40 ligand, respectively. These two subsets up-regulate MHC class II costimulatory molecules as well as the DC maturation marker DC-lysosome-associated membrane protein, and they stimulate naive, allogeneic CD4+ T cells efficiently. These two DC subsets elicit distinct cytokine profiles in CD4+ T cells, with the CD11c- subset inducing higher levels of the Th2 cytokine IL-10. The differential mobilization of distinct DC subsets or DC precursors by in vivo administration of FL and G-CSF offers a novel strategy to manipulate immune responses in humans.

Adjuvants, Immunologic↗
PubMed1998

A foodborne outbreak of Cyclospora cayetanensis at a wedding: clinical features and risk factors for illness.

BACKGROUND: Cyclospora cayetanensis, a coccidian parasite, has increasingly been recognized as a cause of gastrointestinal tract illness. We describe an outbreak of Cyclospora infection following a wedding reception. OBJECTIVES: To investigate and characterize risk factors associated with the outbreak of Cyclospora and to describe the observed clinical course and spectrum of illness. METHODS: Retrospective cohort study involving 94 of the 101 guests who attended a wedding reception at a restaurant in Boston, Mass. RESULTS: Fifty-seven respondents met the case definition of infection; 12 of these had laboratory-confirmed Cyclospora. The epidemic curve was consistent with a point source outbreak with a median incubation period of 7 days. Commonly reported symptoms included diarrhea (100%), weight loss (93%), fatigue (91%), and anorexia (90%). The illness had a characteristic waxing and waning course, with 51 persons (89%) reporting recurring symptoms and 35 (61%) reporting illness lasting more than 3 weeks. By univariate analysis, infection was significantly associated (P<.05) with consumption of wine and a dessert containing raspberries, strawberries, blackberries, and blueberries. Only the dessert remained significant by stratified analysis with an adjusted relative risk of 2.1 (95% confidence interval, 1.4-3.2). CONCLUSIONS: Findings from this study support a point source outbreak of the newly identified pathogen C cayetanensis, with berries as the vehicle of transmission. It suggests that Cyclospora may cause severe diarrhea associated with profound anorexia and weight loss, and should be considered in the evaluation of prolonged gastrointestinal tract illness.

Animals↗
PubMed1998

Biologic activity of interleukin 1 (IL-1) alpha in patients with refractory malignancies.

Interleukin 1 alpha (IL-1 alpha) is a cytokine with pleiotropic effects, including cytotoxic-cytostatic activity against some tumor cell lines. We have conducted a phase I study of recombinant human IL-1 alpha (rhIL-1 alpha) in 17 patients with refractory malignancies to examine its toxicity and biologic activity. rhIL-1 alpha was given as a 2-h IV infusion daily for 5 days at five dose levels (0.08, 0.2, 0.8, 2.0, and 5.0 micrograms/m2). Seventeen patients with malignancies were treated, with no objective tumor responses noted. Common toxicities included: fever (100%), rigors and/or chills (96%), myalgia (54%), and headache (48%). Three patients developed grade III hypotension. The maximum tolerated dose was 2.0 micrograms/m2. rhIL-1 alpha induced a significant increase in absolute neutrophil count over baseline (p < 0.05), a delayed but significant increase in platelet count over baseline (p < 0.05), and there was a marked increase in the number of progenitors [colony-forming units (CFU)-G, CFU-M, CFU-GM, CFU-GEMM and burst-forming units (BFU-E)] observed in the peripheral blood. Nine of 12 evaluable patients showed an increase in bone marrow cellularity or myeloid:erthyroid ratio. Immunophenotyping did not demonstrate an increase in peripheral blood or bone marrow CD34+ cells. Interferon-gamma-mediated monocyte cytotoxicity (MCCTX) was significantly enhanced from baseline (p < 0.001), although an increase in direct MCCTX did not reach statistical significance. In summary, rhIL-1 alpha administration is well tolerated at a dose of 2.0 micrograms/m2 with fever, rigors, myalgia, and headache being the most frequent toxicities. Although there were no objective tumor responses, we have demonstrated significant biologic activity with increased neutrophil and platelet counts, increased peripheral blood progenitor cells, and enhanced interferon-gamma-mediated MCCTX.

Adult↗
PubMed1997

Performance of the new plasma-compatible Advantage blood glucose test strips.

OBJECTIVE: To establish a plasma calibration curve for the Advantage Blood Glucose System that would permit direct comparison with results provided by clinical laboratories. DESIGN AND METHODS: The initial study involved the comparison between the Advantage whole blood referenced results and the laboratory plasma results. The second study validated the plasma-compatibility of the first new lot of Advantage test strips with this new calibration curve. RESULTS: Plasma and whole blood glucose data, obtained at Hôpital Maisonneuve-Rosemont in Montréal, demonstrated the typical differences between these two sample types. Mathematical correction of the Advantage results eliminated this difference. This new equation was then encoded into the code keys of a new lot of Advantage test strips and a second study was conducted to verify the comparability to laboratory plasma glucose. CONCLUSION: The results for the Advantage Blood Glucose System may now be compared directly with the laboratory plasma or serum glucose results.

Blood Chemical Analysis↗
PubMed1997

Split-face comparison of adapalene 0.1% gel and tretinoin 0.025% gel in acne patients.

BACKGROUND: Adapalene is a new naphthoic acid derivative developed for the topical treatment of acne vulgaris. OBJECTIVE: We compared the skin tolerance of adapalene 0.1% gel with tretinoin 0.025% gel in subjects with acne. METHODS: Fifteen acne patient volunteers were enrolled in this investigator-masked, left-right comparison, randomized, controlled, intraindividual study. Adapalene 0.1% gel and tretinoin 0.025% gel were applied once a day to one half-face by the volunteers for 14 consecutive days. Clinical signs (erythema, desquamation, papules, vesicles, edema) and subjective symptoms (tightness, pruritus, burning) were evaluated and scored daily except on weekends. RESULTS: Adapalene 0.1% gel was better tolerated than tretinoin 0.025% gel. The overall mean score calculated from all features combined was significantly higher with tretinoin gel than with adapalene gel (p = 0.002). CONCLUSION: Adapalene 0.1% gel was significantly less irritating than tretinoin 0.025% gel when tested in acne patients.

Acne Vulgaris↗
PubMed1997

Skin tolerance of adapalene 0.1% gel in combination with other topical antiacne treatments.

BACKGROUND: Adapalene (Differin gel) is a new naphthoic acid derivative developed for the topical treatment of acne vulgaris. OBJECTIVE: We assessed, in healthy volunteers, the skin irritancy potential of three combinations, each including adapalene 0.1% gel and one topical marketed antiacne product. METHODS: Twenty-five healthy volunteers were enrolled in a 21-day cumulative irritancy study performed in a double-blind, randomized, controlled, intraindividual design. Five days a week, the three materials (benzoyl peroxide, clindamycin phosphate, and erythromycin) were applied in a nonocclusive manner either alone or in combination with adapalene gel on seven cutaneous sites on the upper back. Adapalene was applied in the evening whereas the three other materials were applied in the morning. Irritation was evaluated and scored daily except on weekends. RESULTS: All materials were well-tolerated when tested alone. The combinations of adapalene 0.1% gel and either benzoyl peroxide, clindamycin phosphate, or erythromycin were also well-tolerated. The mean cumulative irritancy indices indicated that all three combinations were nonirritating. CONCLUSION: Under the conditions of the study, all tested treatments alone or in combination appeared nonirritating.

Adapalene↗
PubMed1997

The use of scintigraphy to provide "proof of concept" for novel polysaccharide preparations designed for colonic drug delivery.

PURPOSE: The aim of the present study was to provide "proof of concept" data in man for novel polysaccharide preparations designed for colonic drug delivery using gamma scintigraphy. METHODS: Two placebo calcium pectinate matrix tablet formulations were studied: one contained calcium pectinate and pectin (CaP/P) and was designed to rapidly disintegrate in the ascending colon, the other contained calcium pectinate and guar gum (CaP/GG) and was designed to disintegrate more slowly, releasing its contents throughout the ascending and transverse colon. Both formulations were enteric coated in order to protect them from the stomach. Ten healthy volunteers received either a CaP/P or CaP/GG tablet, in a randomised cross-over study. Transit and disintegration of the radiolabelled formulations was followed by gamma scintigraphy. Rat studies were conducted in order to verify that the expected colonic degradation of the polysaccharide formulations was as a consequence of bacterial enzyme attack. RESULTS: The in vivo clinical study confirmed the results obtained in the rat and bench in vitro fermentation models; complete tablet disintegration for Formulation CaP/GG appeared to be slower than that of Formulation CaP/P and the time and the location of complete tablet disintegration was more reproducible with Formulation CaP/P compared to Formulation CaP/GG. CONCLUSIONS: These results provide "proof of concept" data for the use of calcium pectinate preparations for drug delivery to the colon and highlight the value of scintigraphy in focusing the development strategy for colonic targeting preparations.

Adult↗
PubMed1996

Effects of PIXY321, a granulocyte-macrophage colony-stimulating factor/interleukin 3 fusion protein, on human tumor colony-forming units taken directly from patients.

PIXY321, a granulocyte-macrophage colony-stimulating factor/interleukin 3 (GM-CSF/IL-3) genetically engineered hybrid, has shown greater biological activity in stimulating committed myeloid progenitors than either GM-CSF or IL-3 in vitro, in vivo, and in patients treated with high-dose chemotherapy. However, one concern is that PIXY321 may stimulate the proliferation of malignant cells which have functional GM-CSF or IL-3 receptors. Therefore, using a human tumor cloning assay, we have tested the effects of several concentrations of PIXY321 ranging from 0.1 to 100 ng/ml on tumor cells taken directly from 98 patients with solid tumors and Hodgkin's or non-Hodgkin's lymphomas. Of the 34 evaluable specimens, including 15 breast cancers, 5 ovarian cancers, 5 lung cancers, and 9 lymphomas, none showed stimulation of tumor growth. Interestingly, a significant inhibition of the tumor proliferation was seen in one breast cancer and in one large cell immunoblastic non-Hodgkin's lymphoma after continuous exposure of PIXY321. In conclusion, the use of PIXY321 to reduce myelosuppression after high-dose chemotherapy appears unlikely to result in stimulation of the growth of malignant cells in patients with lymphoma or cancers of the breast, lung, and ovary.

Breast Neoplasms↗
PubMed1994

Pharmacokinetic analysis of two new sustained-release products of diltiazem designed for twice- and once-daily treatment.

The pharmacokinetics of two new sustained-release (SR) products of diltiazem, Dilapress 120 mg tablets and Dilapress 240 mg tablets, was analysed and characterized in three different studies, in comparison to the following diltiazem SR formulations: Cardizem Retard, Cardizem SR, and Cardizem CD. Dilapress 120, designated for twice-daily dosing, was found to be bioequivalent to Cardizem SR and to Cardizem Retard with mean (+/- SD) relative bioavailability values of 99 +/- 27% and 113 +/- 38%, respectively. Dilapress 240, designed for once-a-day treatment, was found to have a slower absorption rate than Cardizem SR and its extent of absorption was 56 +/- 19% relative to that of Cardizem SR. However, the bioavailability of Dilapress 240 relative to that of Cardizem CD was 118 +/- 46%, indicating that the bioavailability of Cardizem CD relative to that of Cardizem SR was only 54 +/- 29%. Diltiazem is partially available due to a saturable liver first-pass effect. A high dose of Cardizem SR may partially escape this first-pass effect and, thus, achieve a higher extent of absorption than a slower SR product. Consequently, SR products of diltiazem designed for once-daily treatment may not reach the saturation stage in the liver first-pass effect process that diltiazem is susceptible to. Consequently, a twice-daily SR product of diltiazem cannot serve as a reference for extent of absorption assessments of a once-daily SR product.

Absorption↗
PubMed1994

Repeated topical administration of all-trans-retinoic acid and plasma levels of retinoic acids in humans.

BACKGROUND: Vitamin A ingestion raises plasma levels of several potentially teratogenic retinoic acids (RAs) with all-trans and 13-cis configuration, but definitive data concerning the consequences of topical administration of all-trans-RA are lacking. OBJECTIVE: The study objective was to investigate the potential for inducing systemic activity after topical administration of 0.025% all-trans-RA by measuring plasma retinoid levels. METHODS: Plasma levels of all-trans-RA, 13-cis-RA, and 4-oxo-13-cis-RA were measured in four healthy subjects before, during, and after 14 daily topical applications of all-trans-RA. RESULTS: Topical administration of all-trans-RA did not significantly increase plasma levels of all-trans-RA, 13-cis-RA, and 4-oxo-13-cis-RA. Significant decreases in levels of these RAs observed during the night may reflect diurnal variations of retinoid metabolism or lowered absorption of dietary vitamin A. CONCLUSION: Diurnal and nutritional factors influence plasma levels of endogenous retinoids to a greater extent than topical administration of all-trans-RA at doses used for acne therapy, which on the basis of these results appears unlikely to induce systemic effects.

Administration, Topical↗
PubMed1994

Monocyte activation following systemic administration of granulocyte-macrophage colony-stimulating factor.

Twenty-four patients with solid malignancies were treated with granulocyte-macrophage colony-stimulating factor (GM-CSF) on a Phase 1b trial. The objective of the study was to evaluate the effects of GM-CSF on peripheral blood monocyte activation. GM-CSF was administered by subcutaneous injection daily for 14 days. Immune parameters measured were monocyte cytotoxicity against the human colon carcinoma (HT29) cell line, serum tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, and in vitro TNF-alpha and IL-1 beta induction. All patients were evaluable for toxicity. Fifteen patients were evaluable for immunologic response. Treatment with GM-CSF led to a statistically significant enhancement in direct monocyte cytotoxicity against HT29 cells. There was no increase in serum TNF-alpha or IL-1 beta and no consistent in vitro induction of TNF-alpha or IL-1 beta from monocytes posttreatment. Treatment was well tolerated overall. We conclude that treatment with GM-CSF can lead to enhanced monocyte cytotoxicity. Further studies are in progress to evaluate the effect of GM-CSF on other parameters of monocyte functions.

Adult↗
PubMed1993

Barrier function of human skin and human reconstructed epidermis.

The present study compares the stratum corneum of human skin and human reconstructed epidermis by histological examination as well as by estimation of water permeability. Measurement of the percutaneous absorption of benzoic acid, testosterone, and hydrocortisone revealed that under the same experimental conditions the reconstructed epidermis on de-epidermized dermis exhibits a barrier function with qualitative properties similar to that of normal skin: water and benzoic acid penetrate more rapidly than testosterone and hydrocortisone. Quantitatively, however, reconstructed epidermis is more permeable than normal human skin. This points to an impaired barrier function of the epidermis reconstructed in vitro.

Adult↗
PubMed1993

A reliability study of SLEDAI: a disease activity index for systemic lupus erythematosus.

SLEDAI, a disease activity index for systemic lupus erythematosus (SLE) has been validated against other such indices and its reliability has been shown by specialists in SLE. To assess its reliability among less experienced clinicians, we conducted a reliability study with 3 rheumatology trainees and 9 patients with SLE according to a Latin square design. SLEDAI easily distinguished between patients (p = 0.0009), and physician variability was not statistically significant (p = 0.27). Inter and intraobserver agreement were 78.7 and 98.0%, respectively. SLEDAI was thus shown to be a reliable instrument among less experienced observers for the assessment of disease activity in SLE.

Education, Medical, Graduate↗
PubMed1992

Derivation of the SLEDAI. A disease activity index for lupus patients. The Committee on Prognosis Studies in SLE.

OBJECTIVE: To standardize outcome measures in systemic lupus erythematosus (SLE). Three indices were identified which could adequately describe outcome (disease activity, damage from disease, and health status); we describe here the development of the Disease Activity Index. METHODS: Twenty-four variables were identified as important factors in a disease activity index. These were used to generate 574 patient profiles, which were rated on a disease activity scale of 0-10 by 14 rheumatologists. A second rating of 10 of the profiles yielded scores that were not significantly different from the first, indicating that experienced clinicians can reliably make global estimates of disease activity. Multiple regression models were used to estimate the relative importance of the 24 clinical variables in the physicians' global rating of disease activity. These were estimated on a "training set" of 75% of physicians' ratings, and then validated on a "testing set," consisting of the remaining 25% of physicians' ratings. RESULTS: The explanatory power of the models in the training set was high (R2 = 0.93). The models' regression coefficients for the organ systems were simplified for easier use in clinical practice. This generated a "weighted" index of 9 organ systems for disease activity in SLE, the SLEDAI, as follows: 8 for central nervous system and vascular, 4 for renal and musculoskeletal, 2 for serosal, dermal, immunologic, and 1 for constitutional and hematologic. The maximum theoretical score is 105, but in practice, few patients have scores greater than 45. The SLEDAI predicted well the physicians' ratings in the testing set (Pearson's correlation coefficients = 0.64-0.79). CONCLUSION: The SLEDAI is a validated model of experienced clinicians' global assessments of disease activity in lupus. It represents the consensus of a group of experts in the field of lupus research.

Central Nervous System↗