Photodynamic effect of zinc porphyrin on the promastigote and amastigote forms of Leishmania braziliensis.

Leishmaniasis is a neglected disease present in more than 88 countries. The currently adopted chemotherapy faces challenges related to side effects and the development of resistance. Photodynamic therapy (PDT) is emerging as a therapeutic modality for cutaneous leishmaniasis. Zn(ii) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (ZnTE-2-PyP4+, ZnP) is a cationic, water-soluble, zinc porphyrin-based photosensitizer whose photodynamic effect on Leishmania braziliensis was analyzed by evaluating the number of visibly undamaged and motile cells, cell membrane integrity, mitochondrial membrane potential, and ultrastructural damage. Treatment of parasites with ZnP and light induced damage in up to 90% of L. braziliensis promastigote cells. Propidium iodide labeling suggested the loss of plasma membrane integrity. In samples treated with ZnP and light, a hyperpolarization of the mitochondrial membrane potential was also observed. Ultrastructural evaluation of promastigotes after photodynamic treatment indicated a loss of cytoplasmic material and the presence of vacuoles. Scanning electron microscopy showed wrinkling of the plasma membrane and a reduced cell volume. Additionally, the number of amastigotes per macrophage was reduced by about 40% after photodynamic application. The treatment showed no considerable toxicity against mammalian cells. Therefore, the results indicated that PDT associated with ZnTE-2-PyP4+ represents a promising alternative to cutaneous leishmaniasis treatment.

DNA array analysis for red blood cell antigens facilitates the transfusion support with antigen-matched blood in patients with sickle cell disease.

BACKGROUND: Blood samples from patients with sickle cell disease (SCD) present to transfusion service with numerous antibodies, making the searching for compatible red blood cells (RBC) a challenge. To overcome this problem we developed an effective strategy to meet needs of supplying RBC-compatible units to SCD patients using DNA arrays. METHODS: We selected DNA samples from 144 SCD patients with multiple (receiving > 5 units) transfusions previously phenotyped for ABO, Rh(D, C, c, E, e), K1, Fy(a) and Jk(a). We also selected DNA samples from 948 Brazilian blood donors whose ABO/RhD phenotype matched that of the patients. All samples were analysed by DNA array analysis (HEA Beadchip(TM), Bioarray Solutions) to determine polymorphisms associated with antigen expression for 11 blood group systems (Rh, Kell, Kidd, Duffy, MNS, Dombrock, Lutheran, Landsteiner-Wiener, Diego, Colton, Scianna); and one mutation associated with haemoglobinopathies. RESULTS: Based on genotype results we were able to predict phenotype-compatible donors needed in order to provide compatible units to this group of patients. Based on their ABO/Rh phenotype we were able to find in this pool of donors compatible units for 134 SCD patients. CONCLUSION: Blood group genotyping by DNA array contributes to the management of transfusions in SCD patients by facilitating the transfusion support with antigen-matched blood. It has the potential to improve the life of thousands of SCD-transfused patients by reducing mortality due to transfusion reactions and immunization.

Molecular studies of DO alleles reveal that JO is more prevalent than HY in Brazil, whereas HY is more prevalent in New York.

Because of the scarcity of anti-Hy and anti-Jo(a), hemagglutination typing for the Dombrock blood group system antigens, Hy and Jo(a), is not feasible. The molecular bases associated with these antigens have been determined, making it possible to distinguish HY and JO from wild-type DO. This provides a tool to predict the probable phenotype of patients and to screen for antigen-negative donors. PCR-RFLP assays and a microchip assay were used to determine the frequency of HY and JO alleles in donors from Brazil and New York. DNA from random Brazilian donors, 288 by PCR-RFLP and 599 by the bead array method (BeadChip, BioArray Solutions, Warren, NJ), was tested to determine 323G/T (HY+/HY-) and 350C>T (JO+/JO-) single-nucleotide polymorphisms. In New York, 27,226 donors who self-identified as being African American were tested by hemagglutination with anti-Gy(a). Nonreactive and weakly reactive samples were tested by PCR-RFLP for the same alleles as listed above. In Brazil, 30 (3.4%) of the samples were JO/DO and 13 (1.4%) were HY/DO. In New York, of the samples that had HY or JO alleles, 14 were homozygous HY/HY 132 were heterozygous HY/DO, 13 were heterozygous HY/JO, 14 were heterozygous JO/DO, and 3 were homozygous JO/JO. These results show that in donors from Brazil, JO (30 alleles) is more than twice as prevalent as HY (13 alleles), whereas in donors from New York, HY (173 alleles) was more than five times more common than JO (33 alleles).