What's new for 'Trypanosomatids' in PubMed

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Sent on Thursday, 2011 Jun 16
Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results

Items 1 - 3 of 3

1.	PLoS One. 2011;6(6):e20786. Epub 2011 Jun 6. Intracellular targeting specificity of novel phthalocyanines assessed in a host-parasite model for developing potential photodynamic medicine. Dutta S, Ongarora BG, Li H, Vicente Mda G, Kolli BK, Chang KP. Source Department of Microbiology/Immunology, Chicago Medical School/Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America. Abstract Photodynamic therapy, unlikely to elicit drug-resistance, deserves attention as a strategy to counter this outstanding problem common to the chemotherapy of all diseases. Previously, we have broadened the applicability of this modality to photodynamic vaccination by exploiting the unusual properties of the trypanosomatid protozoa, Leishmania, i.e., their innate ability of homing to the phagolysosomes of the antigen-presenting cells and their selective photolysis therein, using transgenic mutants endogenously inducible for porphyrin accumulation. Here, we extended the utility of this host-parasite model for in vitro photodynamic therapy and vaccination by exploring exogenously supplied photosensitizers. Seventeen novel phthalocyanines (Pcs) were screened in vitro for their photolytic activity against cultured Leishmania. Pcs rendered cationic and soluble (csPcs) for cellular uptake were phototoxic to both parasite and host cells, i.e., macrophages and dendritic cells. The csPcs that targeted to mitochondria were more photolytic than those restricted to the endocytic compartments. Treatment of infected cells with endocytic csPcs resulted in their accumulation in Leishmania-containing phagolysosomes, indicative of reaching their target for photodynamic therapy, although their parasite versus host specificity is limited to a narrow range of csPc concentrations. In contrast, Leishmania pre-loaded with csPc were selectively photolyzed intracellularly, leaving host cells viable. Pre-illumination of such csPc-loaded Leishmania did not hinder their infectivity, but ensured their intracellular lysis. Ovalbumin (OVA) so delivered by photo-inactivated OVA transfectants to mouse macrophages and dendritic cells were co-presented with MHC Class I molecules by these antigen presenting cells to activate OVA epitope-specific CD8+T cells. The in vitro evidence presented here demonstrates for the first time not only the potential of endocytic csPcs for effective photodynamic therapy against Leishmania but also their utility in photo-inactivation of Leishmania to produce a safe carrier to express and deliver a defined antigen with enhanced cell-mediated immunity.
	PMID: 21673971 [PubMed - in process]

2.	Pediatr Infect Dis J. 2011 Jul;30(7):630-1. Visceral leishmaniasis as a cause of persistent Fever in pediatric hodgkin lymphoma. Pani CK, Mohapatra S, Samantaray JC, Bakhshi S. Source Department of Medical Oncology, Dr. B. R. A. Institute Rotary Cancer Hospital (Pani) Department of Microbiology, All India Institute of Medical Sciences (Mohapatra, Samantaray) Department of Medical Oncology, Dr. B. R. A. Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India, sambakh@hotmail.com (Bakhshi).
	PMID: 21673550 [PubMed - in process]

3.	Photomed Laser Surg. 2011 Jun 14. [Epub ahead of print] Photodynamic Therapy Using Methylene Blue to Treat Cutaneous Leishmaniasis. Song D, Lindoso JA, Oyafuso LK, Kanashiro EH, Cardoso JL, Uchoa AF, Tardivo JP, Baptista MS. Source 1 Departamento de Bioquímica-Instituto de Química, Universidade de São Paulo , São Paulo-SP, Brazil . Abstract Abstract Objective: The purpose of this study was to show the efficiency and underlying mechanism of action of photodynamic therapy (PDT) using methylene blue (MB) and non-coherent light sources to treat cutaneous leishmaniasis (CL). Background data: Systemic treatment can cause severe side effects, and PDT using porphyrin precursors as sensitizers has been used as an alternative to treat CL. MB has been used under illumination or in the dark to treat a wide range of medical conditions, and it exhibits antimicrobial activity against protozoa and viruses. Methods: In in vitro tests, the cell viability (via a MTT colorimetric assay) of Leishmania amazonensis parasites was evaluated as a function of MB concentration. In in vivo experiments, we analyzed the treatment of two lesions from a patient with leishmaniasis. The patient received a low dose of pentavalent antimony (SbV), and one lesion was treated with PDT. Results: We observed IC(50) decreases from 100 to 20 μM in response to PDT when MB was used in different concentrations in in vitro tests. Use of SbV in combination with the PDT protocol produced faster wound recovery when compared with the use of SbV alone. Conclusions: The in vitro experiments and the results from the clinical case suggest that the inexpensive PDT protocol that is based on MB and RL50® may be used to treat CL caused by L. amazonensis.
	PMID: 21671755 [PubMed - as supplied by publisher]