Fecha: 
01/11/2007
Linea de Investigacion: 

Abstract

New therapeutic alternatives against leishmaniasis remain a priority. The activity of azithromycin against Leishmania (Leishmania) major has been previously demonstrated. Different responses among species of Leishmania make species-specific drug screening necessary. The activity of azithromycin against Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis was evaluated in golden hamsters infected through footpad injections of metacyclic promastigotes, and compared with untreated controls and animals treated with meglumine antimoniate. Footpad thickness, lesion cultures and dissemination sites were analyzed. Treatment of golden hamsters with oral azithromycin at 450mg/kg had no activity against infections with Leishmania (Leishmania) amazonensis. For infections due to Leishmania (Viannia) braziliensis, azithromycin demonstrated significant activity relative to untreated controls, but inferior to meglumine antimoniate, for controlling lesion size. Neither drug was able to totally eliminate parasites from the lesions. It was concluded that azithromycin has activity against Leishmania (Viannia) braziliensis but not against Leishmania (Leishmania) amazonensis in this model.

Fecha: 
01/10/2007
Linea de Investigacion: 

Abstract

Azithromycin was compared with meglumine antimoniate for treatment of patients with cutaneous leishmaniasis. Patients were randomized to receive oral azithromycin, 500 mg/day (22 patients) or intramuscular meglumine antimoniate, 10 mg Sb/kg/day (23 patients), both for 28 days, with a second cycle of 15 days if necessary, and followed-up for one year after completion of treatment. Efficacy, defined as complete re-epithelization without relapse for 12 months after completing therapy, was 82.6% (95% confidence interval [CI] = 67-98%) for meglumine antimoniate and 45.5% (95% CI = 25-66%) for azithromycin. All patients who failed treatment with azithromycin were treated with meglumine antimoniate and clinically cured. Azithromycin was well tolerated; meglumine antimoniate caused arthralgias and local symptoms in 78% of the patients. In 17 cases, species identification was obtained; Leishmania (Viannia) braziliensis was identified in all of them. For the treatment of American cutaneous leishmaniasis caused by L. (V.) braziliensis, meglumine antimoniate is significatively more efficacious than azithromycin, which was clinically curative in almost half of the patients and well-tolerated.

Fecha: 
01/04/2006
Linea de Investigacion: 

Abstract

OBJECTIVE:

To evaluate clinical, immunologic, and virologic performance of patients with nadir CD4 counts of >350 cells/microL upon treatment interruption.

DESIGN:

Randomized, open-label clinical trial of 48 weeks' duration.

METHODS:

Patients on effective highly active antiretroviral therapy, with nadir CD4 counts of >350 cells/microL and peak viral loads of <50,000 copies/mL were randomized to continue therapy or to interrupt antiretroviral medication. End points for patients with treatment interruption were CD4 counts of <350 cells/microL, viral loads of >1 log above the pretherapy values, or clinical symptoms attributable to HIV, at which point treatment was restarted. In the continuation group, the end points were virologic failure, opportunistic infections, and treatment discontinuation due to toxicities.

RESULTS:

Twenty patients were randomized to stop therapy and 16 patients to continue. Median CD4 counts at baseline were 643 cells/microL for the interruption group and 633 cells/microL for the continuation group. No end points were reached in the interruption group. By week 8, viral load returned to values comparable to those of pretherapy in all patients in the interruption group and remained stable until week 48. CD4 counts dropped in the interruption group (median loss of 156 cells/microL) at week 48. Significant decreases in venous lactate were observed in the interruption group.

CONCLUSIONS:

Treatment interruptions in patients with nadir CD4 counts of >350 cells/microL seem safe for at least 48 weeks. Pretherapy viral load appears as a valuable tool to predict its level at week 48.

Fecha: 
01/01/2006
Linea de Investigacion: 

Abstract

Anti-native DNA antibodies can be detected by indirect immunofluorescence assay with Crithidia luciliae, displaying an annular image due to a kinetoplast containing double stranded DNA. Other structures such as membrane, flagellum and basal corpuscle can be stained as well, showing what is called atypical fluorescent images. As C. luciliae belongs to the Trypanosomatidae family, which include the human pathogens Trypanosoma cruzi and Leishmania spp., it was considered that these atypical images could be caused by cross-reactions. Serological studies for Chagas' disease were performed in 105 serum samples displaying atypical images. Sixty four percent of the samples from non endemic and 78.3% from endemic areas for Chagas' disease showed fluorescence in both, membrane and flagellum (joint image). Fifty samples from normal blood donors and 57 samples from patients with conective tissue diseases were tested with C. luciliae. None of them presented the joint image except for two patients with lupus who were also chagasic. In addition, 54 samples from chagasic patients were studied and all of them presented the joint image. We also studied 46 samples from patients with leishmaniasis from whom 28 were coinfected with T. cruzi. The joint image was observed in 88.0% of the samples with leishmaniasis and in 89.3% of the co-infected samples. The results suggest that C. luciliae could be used as an economical, and of low risk, alternative substrate for the serological diagnosis of Chagas' disease, even though it does not discriminate for Leishmania spp. infection. This study also suggests that whenever atypical images are observed in C. luciliae during the search for anti-DNA antibodies, it would be convenient to submit the patient to clinical and serological tests for the diagnosis of leishmaniosis and Chagas' disease.

Autor/es: 
Fecha: 
01/05/2005
Linea de Investigacion: 

Abstract

Sixteen Leishmania stocks, 15 isolated from patients with cutaneous (CL), mucocutaneous (MCL), or recurrent cutaneous leishmaniasis, plus one from a dog with CL in Salta and Corrientes Provinces, Argentina, were studied by multilocus enzyme electrophoresis. Thirteen of the stocks from humans were grouped in two zymodemes; nine termed as KMS 1, four as KMS 2, and assigned to Leishmania (Viannia) braziliensis. Two additional stocks from CL cases expressed a KMS 4 enzyme profile, corresponding to L. (V.) guyanensis. Although the parasites from the dog were also assigned to L. (V.) braziliensis, its zymodeme, KMS 3, was not expressed in any of the current human isolates. The characterization of Leishmania from a dog was done for the first time in Argentina. The importance of the intraspecific polymorphism in the induction of clinical forms and in the host-reservoir concept is briefly discussed, based on the zymodeme data of isolates from humans and dogs. The presence of L. (V.) guyanensis was confirmed in the country.

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