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Ricardo Palacios

Publications and source records attributed to Ricardo Palacios.

7 recordsLinked to original sources
PubMed2007

Pharmacokinetics of antimony in children treated for leishmaniasis with meglumine antimoniate.

BACKGROUND: In some settings, the response to pentavalent antimonial therapy for leishmaniasis may be lower in children than in adults. We hypothesized that there are age-dependent pharmacokinetic differences of potential clinical relevance. METHODS: We compared the pharmacokinetics of antimony (Sb) in adults and 2 groups of children 3-6 years old who had cutaneous leishmaniasis treated with intramuscular meglumine antimoniate. Adults (n=9) and the first group of children (n=9) received 20 mg Sb/kg/day for 20 days; the second group of children (n=6) received 20 mg Sb/kg for 19 days and 30 mg Sb/kg on day 20. Drug exposure was assessed by the area under the 24-h time-concentration curve (AUC(0-24)) in plasma. RESULTS: Children (vs. adults) who received 20 mg/kg had a 42% lower AUC(0-24) (mean +/- SE, 111+/-7 vs. 190+/-10 mg x h/L, compared with adults; P<.001), a 16% lower peak concentration (32.7+/-0.9 vs. 38.8+/-2.1 mg/L; P=.04), and a 75% higher weight-adjusted clearance (0.185+/-0.013 vs. 0.106+/-0.006 L/h/kg; P<.001). The 30 mg/kg dose in children increased the AUC(0-24) to 164+/-10 mg x h/L and the peak concentration to 43.8+/-2.3 mg/L. CONCLUSIONS: Drug exposure is significantly lower in children than in adults treated with the same weight-adjusted regimen of meglumine antimoniate, which primarily stems from a higher antimony clearance rate.

Adult↗
PubMed2006

Evidence for leishmania (viannia) parasites in the skin and blood of patients before and after treatment.

BACKGROUND: American cutaneous leishmaniasis is considered to be a zoonotic disease transmitted by sand flies that feed on infected sylvatic mammals. However, the "domestication" of transmission and the increase in treatment failure with antimonial drugs have raised the suspicion of anthroponotic transmission of American cutaneous leishmaniasis. METHODS: The objective of the present study was to explore the potential of humans as a source of infection for sand flies. Biological (xenodiagnosis and culture) and molecular (polymerase chain reaction/Southern blot) detection methods were used to evaluate peripheral-blood monocytes and tissue fluids from sites accessible to sand flies from 59 adult patients with parasitologically confirmed American cutaneous leishmaniasis. RESULTS: Overall, 44.1% of patients (26/59) presented biological and/or molecular evidence of Leishmania parasites in normal skin, peripheral-blood monocytes, lesion scars, or lesion border (by xenodiagnosis) before (18/59 [30.5%]) or after (10/27 [37.0%]) treatment. Leishmania parasites were cultured from the unaffected skin of 2 (3.6%) of 55 patients, and xenodiagnosis gave positive results for 5 (8.8%) of 57 patients before treatment. CONCLUSIONS: The presence of Leishmania parasites in the unaffected skin and peripheral-blood monocytes of a high proportion of patients even after treatment and the acquisition of infection by sand flies support the plausibility of anthroponotic transmission of American cutaneous leishmaniasis.

Adolescent↗
PubMed2005

Sublingual immunotherapy for hazelnut food allergy: a randomized, double-blind, placebo-controlled study with a standardized hazelnut extract.

BACKGROUND: Food allergy may be life-threatening, and patients affected need to receive accurate diagnoses and treatment. Hazelnut has often been implicated as responsible for allergic reactions, and trace quantities can induce systemic reactions. OBJECTIVE: The aim of this study was to evaluate the efficacy and tolerance of sublingual immunotherapy with a standardized hazelnut extract in patients allergic to hazelnut. METHODS: This was a randomized, double-blind, placebo-controlled study. Inclusion criteria were a history of hazelnut allergy and positive skin prick test and double-blind placebo-controlled food challenge results. Patients were then randomly assigned into 2 treatment groups (hazelnut immunotherapy or placebo). Efficacy was assessed by double-blind, placebo-controlled food challenge after 8 to 12 weeks of treatment. Blood samples were drawn for measurement of specific IgE, IgG(4), and serum cytokines before and after treatment. RESULTS: Twenty-three patients were enrolled and divided into 2 treatment groups. Twenty-two patients reached the planned maximum dose at 4 days. Systemic reactions were observed in only 0.2% of the total doses administered. Mean hazelnut quantity provoking objective symptoms increased from 2.29 g to 11.56 g (P = .02; active group) versus 3.49 g to 4.14 g (placebo; NS). Moreover, almost 50% of patients who underwent active treatment reached the highest dose (20 g), but only 9% in the placebo. Laboratory data showed an increase in IgG(4) and IL-10 levels after immunotherapy in only the active group. CONCLUSION: Our data confirm significant increases in tolerance to hazelnut after sublingual immunotherapy as assessed by double-blind, placebo-controlled food challenge, and good tolerance to this treatment.

Administration, Sublingual↗
PubMed2005

Safety and elicitation of humoral and cellular responses in colombian malaria-naive volunteers by a Plasmodium vivax circumsporozoite protein-derived synthetic vaccine.

Substantial experimental evidence indicates that the Plasmodium circumsporozoite (CS) protein has great potential as a vaccine candidate. We tested the safety and immunogenicity of vaccines composed of P. vivax CS-derived synthetic peptides. Sixty-nine healthy, malaria-naive volunteers were randomized to receive three injections of placebo or synthetic proteins N, R, or C (10, 30, or 100 microg/dose) in a double-blinded fashion. Vaccines were well tolerated and no serious adverse events were observed. Peptides N and R elicited humoral responses at all doses; peptide C elicicted these responses only at doses of 30 and 100 microg. The N peptide at a dose of 100 microg elicited the greatest antibody response. Antibodies to the three peptides recognized P. vivax sporozoites in an immunofluorescent antibody test. Peripheral blood mononuclear cells from most immunized volunteers also produced interferon-gamma upon peptide in vitro stimulation. These vaccines appear safe, well tolerated, and immunogenic in malaria-naive volunteers. Further optimization and development of this vaccine is being attempted to conduct phase II clinical trials.

Adolescent↗
PubMed2003

A genomic screen of Spanish multiple sclerosis patients reveals multiple loci associated with the disease.

In order to identify the genomic regions that might confer susceptibility to multiple sclerosis (MS) in the Spanish population, we have performed a genome-wide screen for association in patients with MS using pooled DNA from 200 clinical cases and 200 healthy controls. The pools were typed using 5546 microsatellites. The typing was repeated for the most promising 1269 markers after which 191 potentially associated markers were identified. Eleven of these markers map to the MHC region, and 14 to non-MHC regions identified in previous linkage screens. Our results provide support for the presence of multiple coding regions that contain MS susceptibility genes of small or moderate effect.

Adult↗
PubMed2003

IgG antibody reactivity to Borrelia burgdorferi sensu stricto antigens in patients with morphea in Colombia.

BACKGROUND: Morphea and lichen sclerosus et atrophicus (LSA) are sclerotic skin lesions of unknown etiology involving connective tissue. The hypothesis of a borrelial origin of morphea and LSA is currently controversial. METHODS: Immunoglobulin G (IgG) immunoblot serologies against Borrelia burgdorferi in patients with morphea and LSA were analyzed and compared with those from healthy donors and patients with syphilis to determine the association with a probable borrelial agent in Colombia. RESULTS: No significant differences in the number of reactive antigenic bands were found between morphea/LSA patients and syphilis patients or healthy donors. The presence of at least one of the following bands, p28, p39, or p45, was the criterion most able to distinguish morphea/LSA, yielding a specificity of 95% and a sensitivity of 28.6%. Using this criterion as evidence of putative exposure to a causative borrelial agent, sclerotic skin lesions had an odds ratio of 7.60 (95% confidence interval, 1.47-39.23). CONCLUSIONS: These results could be explained by cross-reactivity; however, the partial shared reactivity of sera from patients with syphilis and morphea/LSA does not rule out the possibility that a new spirochetal agent, unrelated to B. burgdorferi or Treponemas, may be the causative agent of morphea/LSA in Colombia.

Adolescent↗