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AFLP Polymorphisms Allow High Resolution Genetic Analysis of American Tegumentary Leishmaniasis Agents Circulating in Panama and Other Members of the Leishmania Genus
Get PDFAmerican Tegumentary Leishmaniasis is caused by parasites of the genus Leishmania, and causes significant health problems throughout the Americas. In Panama, Leishmania parasites are endemic, causing thousands of new cases every year, mostly of the cutaneous form. In the last years, the burden of the disease has increased, coincident with increasing disturbances in its natural sylvatic environments. The study of genetic variation in parasites is important for a better understanding of the biology, population genetics, and ultimately the evolution and epidemiology of these organisms. Very few attempts have been made to characterize genetic polymorphisms of parasites isolated from Panamanian patients of cutaneous leishmaniasis. Here we present data on the genetic variability of local isolates of Leishmania, as well as specimens from several other species, by means of Amplified Fragment Length Polymorphisms (AFLP), a technique seldom used to study genetic makeup of parasites. We demonstrate that this technique allows detection of very high levels of genetic variability in local isolates of Leishmania panamensis in a highly reproducible manner. The analysis of AFLP fingerprints generated by unique selective primer combinations in L. panamensis suggests a predominant clonal mode of reproduction. Using fluorescently labeled primers, many taxon-specific fragments were identified which may show potential as species diagnostic fragments. The AFLP permitted a high resolution genetic analysis of the Leishmania genus, clearly separating certain groups among L. panamensis specimens and highly related species such as L. panamensis and L. guyanensis. The phylogenetic networks reconstructed from our AFLP data are congruent with established taxonomy for the genus Leishmania, even when using single selective primer combinations. Results of this study demonstrate that AFLP polymorphisms can be informative for genetic characterization in Leishmania parasites, at both intra and inter-specific levels.American Tegumentary Leishmaniasis is caused by parasites of the genus Leishmania, and causes significant health problems throughout the Americas. In Panama, Leishmania parasites are endemic, causing thousands of new cases every year, mostly of the cutaneous form. In the last years, the burden of the disease has increased, coincident with increasing disturbances in its natural sylvatic environments. The study of genetic variation in parasites is important for a better understanding of the biology, population genetics, and ultimately the evolution and epidemiology of these organisms. Very few attempts have been made to characterize genetic polymorphisms of parasites isolated from Panamanian patients of cutaneous leishmaniasis. Here we present data on the genetic variability of local isolates of Leishmania, as well as specimens from several other species, by means of Amplified Fragment Length Polymorphisms (AFLP), a technique seldom used to study genetic makeup of parasites. We demonstrate that this technique allows detection of very high levels of genetic variability in local isolates of Leishmania panamensis in a highly reproducible manner. The analysis of AFLP fingerprints generated by unique selective primer combinations in L. panamensis suggests a predominant clonal mode of reproduction. Using fluorescently labeled primers, many taxon-specific fragments were identified which may show potential as species diagnostic fragments. The AFLP permitted a high resolution genetic analysis of the Leishmania genus, clearly separating certain groups among L. panamensis specimens and highly related species such as L. panamensis and L. guyanensis. The phylogenetic networks reconstructed from our AFLP data are congruent with established taxonomy for the genus Leishmania, even when using single selective primer combinations. Results of this study demonstrate that AFLP polymorphisms can be informative for genetic characterization in Leishmania parasites, at both intra and inter-specific levels
High clustering rates of multidrug-resistant Mycobacterium tuberculosisgenotypes in Panama
Get PDFBackground: Tuberculosis continues to be one of the leading causes of death worldwide and in the American region. Although multidrug-resistant tuberculosis (MDR-TB) remains a threat to TB control in Panama, few studies have focused in typing MDR-TB strains. The aim of our study was to characterize MDR Mycobacterium tuberculosis clinical isolates using PCR-based genetic markers. Methods: From 2002 to 2004, a total of 231 Mycobacterium tuberculosis isolates from TB cases country-wide were screened for antibiotic resistance, and MDR-TB isolates were further genotyped by double repetitive element PCR (DRE-PCR), (GTG)5-PCR and spoligotyping. Results: A total of 37 isolates (0.85%) were resistant to both isoniazid (INH) and rifampicin (RIF). Among these 37 isolates, only two (5.4%) were resistant to all five drugs tested. Dual genotyping using DRE-PCR and (GTG)5-PCR of MDR Mycobacterium tuberculosis isolates revealed eight clusters comprising 82.9% of the MDR-TB strain collection, and six isolates (17.1%) showed unique fingerprints. The spoligotyping of MDR-TB clinical isolates identified 68% as members of the 42 (LAM9) family genotype.Background: Tuberculosis continues to be one of the leading causes of death worldwide and in the American region. Although multidrug-resistant tuberculosis (MDR-TB) remains a threat to TB control in Panama, few studies have focused in typing MDR-TB strains. The aim of our study was to characterize MDR Mycobacterium tuberculosis clinical isolates using PCR-based genetic markers. Methods: From 2002 to 2004, a total of 231 Mycobacterium tuberculosis isolates from TB cases country-wide were screened for antibiotic resistance, and MDR-TB isolates were further genotyped by double repetitive element PCR (DRE-PCR), (GTG)5-PCR and spoligotyping. Results: A total of 37 isolates (0.85%) were resistant to both isoniazid (INH) and rifampicin (RIF). Among these 37 isolates, only two (5.4%) were resistant to all five drugs tested. Dual genotyping using DRE-PCR and (GTG)5-PCR of MDR Mycobacterium tuberculosis isolates revealed eight clusters comprising 82.9% of the MDR-TB strain collection, and six isolates (17.1%) showed unique fingerprints. The spoligotyping of MDR-TB clinical isolates identified 68% as members of the 42 (LAM9) family genotype
Rough titanium alloys regulate osteoblast production of angiogenic factors
Get PDFMultiple biomaterials are clinically available to spine surgeons for performing interbody fusion. Poly-ether-ether-ketone (PEEK) is used frequently for lumbar spine interbody fusion, but alternative materials are also used, including titanium (Ti) alloys. Previously, we showed that osteoblasts exhibit a more differentiated phenotype when grown on machined or grit-blasted titanium aluminum vanadium (Ti6Al4V) alloys with micron-scale roughened surfaces than when grown on smoother Ti6Al4V surfaces or on tissue culture polystyrene (TCPS). We hypothesized that osteoblasts cultured on rough Ti alloy substrates would present a more mature osteoblast phenotype than cells cultured on PEEK, suggesting that textured Ti6Al4V implants may provide a more osteogenic surface for interbody fusion devices. PURPOSE: The aim of the present study was to compare osteoblast response to smooth Ti6Al4V (sTiAlV) and roughened Ti6Al4V (rTiAlV) with their response to PEEK with respect to differentiation and production of factors associated with osteogenesis. STUDY DESIGN: This in vitro study compared the phenotype of human MG63 osteoblast-like cells cultured on PEEK, sTiAlV, or rTiAlV surfaces and their production of bone morphogenetic proteins (BMPs). METHODS: Surface properties of PEEK, sTiAlV, and rTiAlV discs were determined. Human MG63 cells were grown on TCPS and the discs. Confluent cultures were harvested, and cell number, alkaline phosphatase–specific activity, and osteocalcin were measured as indicators of osteoblast maturation. Expression of messenger RNA (mRNA) for BMP2 and BMP4 was measuredMultiple biomaterials are clinically available to spine surgeons for performing interbody fusion. Poly-ether-ether-ketone (PEEK) is used frequently for lumbar spine interbody fusion, but alternative materials are also used, including titanium (Ti) alloys. Previously, we showed that osteoblasts exhibit a more differentiated phenotype when grown on machined or grit-blasted titanium aluminum vanadium (Ti6Al4V) alloys with micron-scale roughened surfaces than when grown on smoother Ti6Al4V surfaces or on tissue culture polystyrene (TCPS). We hypothesized that osteoblasts cultured on rough Ti alloy substrates would present a more mature osteoblast phenotype than cells cultured on PEEK, suggesting that textured Ti6Al4V implants may provide a more osteogenic surface for interbody fusion devices. PURPOSE: The aim of the present study was to compare osteoblast response to smooth Ti6Al4V (sTiAlV) and roughened Ti6Al4V (rTiAlV) with their response to PEEK with respect to differentiation and production of factors associated with osteogenesis. STUDY DESIGN: This in vitro study compared the phenotype of human MG63 osteoblast-like cells cultured on PEEK, sTiAlV, or rTiAlV surfaces and their production of bone morphogenetic proteins (BMPs). METHODS: Surface properties of PEEK, sTiAlV, and rTiAlV discs were determined. Human MG63 cells were grown on TCPS and the discs. Confluent cultures were harvested, and cell number, alkaline phosphatase–specific activity, and osteocalcin were measured as indicators of osteoblast maturation. Expression of messenger RNA (mRNA) for BMP2 and BMP4 was measure
Randomized, Double-Blinded, Phase 2 Trial of WR 279,396 (Paromomycin and Gentamicin) for Cutaneous Leishmaniasis in Panama
Get PDFIn this randomized, double-blinded Phase 2 trial, 30 patients with Leishmania panamensis cutaneous leishmaniasis were randomly allocated (1:1) to receive once daily topical treatment with WR 279,396 (15% paromomycin + 0.5% gentamicin) or Paromomycin Alone (15% paromomycin) for 20 days. The index lesion cure rate after 6 months follow-up was 13 of 15 (87%) for WR 279,396 and 9 of 15 (60%) for Paromomycin Alone (P = 0.099). When all treated lesions were included, the final cure rate for WR 279,398-treated patients was again 87%, but the final cure rate for Paromomycin Alone-treated patients was 8 of 15 (53.3%; P = 0.046). Both creams were well tolerated with mild application site reactions being the most frequent adverse event. The increased final cure rate in the WR 279,396 group in this small Phase 2 study suggests that the combination product may provide greater clinical benefit than paromomycin monotherapy against L. panamensis cutaneous leishmaniasis.In this randomized, double-blinded Phase 2 trial, 30 patients with Leishmania panamensis cutaneous leishmaniasis were randomly allocated (1:1) to receive once daily topical treatment with WR 279,396 (15% paromomycin + 0.5% gentamicin) or Paromomycin Alone (15% paromomycin) for 20 days. The index lesion cure rate after 6 months follow-up was 13 of 15 (87%) for WR 279,396 and 9 of 15 (60%) for Paromomycin Alone (P = 0.099). When all treated lesions were included, the final cure rate for WR 279,398-treated patients was again 87%, but the final cure rate for Paromomycin Alone-treated patients was 8 of 15 (53.3%; P = 0.046). Both creams were well tolerated with mild application site reactions being the most frequent adverse event. The increased final cure rate in the WR 279,396 group in this small Phase 2 study suggests that the combination product may provide greater clinical benefit than paromomycin monotherapy against L. panamensis cutaneous leishmaniasis
Randomized, Double-Blinded, Phase 2 Trial of WR 279,396 (Paromomycin and Gentamicin) for Cutaneous Leishmaniasis in Panama
Get PDFIn this randomized, double-blinded Phase 2 trial, 30 patients with Leishmania panamensis cutaneous leishmaniasis were randomly allocated (1:1) to receive once daily topical treatment with WR 279,396 (15% paromomycin + 0.5% gentamicin) or Paromomycin Alone (15% paromomycin) for 20 days. The index lesion cure rate after 6 months follow-up was 13 of 15 (87%) for WR 279,396 and 9 of 15 (60%) for Paromomycin Alone (P = 0.099). When all treated lesions were included, the final cure rate for WR 279,398-treated patients was again 87%, but the final cure rate for Paromomycin Alone-treated patients was 8 of 15 (53.3%; P = 0.046). Both creams were well tolerated with mild application site reactions being the most frequent adverse event. The increased final cure rate in the WR 279,396 group in this small Phase 2 study suggests that the combination product may provide greater clinical benefit than paromomycin monotherapy against L. panamensis cutaneous leishmaniasis.In this randomized, double-blinded Phase 2 trial, 30 patients with Leishmania panamensis cutaneous leishmaniasis were randomly allocated (1:1) to receive once daily topical treatment with WR 279,396 (15% paromomycin + 0.5% gentamicin) or Paromomycin Alone (15% paromomycin) for 20 days. The index lesion cure rate after 6 months follow-up was 13 of 15 (87%) for WR 279,396 and 9 of 15 (60%) for Paromomycin Alone (P = 0.099). When all treated lesions were included, the final cure rate for WR 279,398-treated patients was again 87%, but the final cure rate for Paromomycin Alone-treated patients was 8 of 15 (53.3%; P = 0.046). Both creams were well tolerated with mild application site reactions being the most frequent adverse event. The increased final cure rate in the WR 279,396 group in this small Phase 2 study suggests that the combination product may provide greater clinical benefit than paromomycin monotherapy against L. panamensis cutaneous leishmaniasis
Copper interactions with DNA of chromatin and its rolein neurodegenerative disorders.
Get PDFIn this study, we have demonstrated the conformational changes to DNA induced by abnormal interactions of copper using circular dichroism, in combination with UV-absorbance and fluorescence spectroscopy. Results confirm that binding of copper to bases of DNA in chromatin is concentration dependent. Binding efficiency of Cu2+ ions to DNA is increased in proportion to the degree of unwinding of the double helix induced by denaturation. Altered B-DNA conformation will alter the integrity of DNA which may affect the normal process of DNA replication and transcription. Copper induced DNA damage in the brain may cause neurotoxicity and the neuronal cell death and is implicated in Alzheimer's disease and other neurological disorders.In this study, we have demonstrated the conformational changes to DNA induced by abnormal interactions of copper using circular dichroism, in combination with UV-absorbance and fluorescence spectroscopy. Results confirm that binding of copper to bases of DNA in chromatin is concentration dependent. Binding efficiency of Cu2+ ions to DNA is increased in proportion to the degree of unwinding of the double helix induced by denaturation. Altered B-DNA conformation will alter the integrity of DNA which may affect the normal process of DNA replication and transcription. Copper induced DNA damage in the brain may cause neurotoxicity and the neuronal cell death and is implicated in Alzheimer's disease and other neurological disorders
Randomized, Double-Blinded, Phase 2 Trial of WR 279,396 (Paromomycin and Gentamicin) for Cutaneous Leishmaniasis in Panama
Get PDFIn this randomized, double-blinded Phase 2 trial, 30 patients with Leishmania panamensis cutaneous leishmaniasis were randomly allocated (1:1) to receive once daily topical treatment with WR 279,396 (15% paromomycin + 0.5% gentamicin) or Paromomycin Alone (15% paromomycin) for 20 days. The index lesion cure rate after 6 months follow-up was 13 of 15 (87%) for WR 279,396 and 9 of 15 (60%) for Paromomycin Alone (P = 0.099). When all treated lesions were included, the final cure rate for WR 279,398-treated patients was again 87%, but the final cure rate for Paromomycin Alone-treated patients was 8 of 15 (53.3%; P = 0.046). Both creams were well tolerated with mild application site reactions being the most frequent adverse event. The increased final cure rate in the WR 279,396 group in this small Phase 2 study suggests that the combination product may provide greater clinical benefit than paromomycin monotherapy against L. panamensis cutaneous leishmaniasisIn this randomized, double-blinded Phase 2 trial, 30 patients with Leishmania panamensis cutaneous leishmaniasis were randomly allocated (1:1) to receive once daily topical treatment with WR 279,396 (15% paromomycin + 0.5% gentamicin) or Paromomycin Alone (15% paromomycin) for 20 days. The index lesion cure rate after 6 months follow-up was 13 of 15 (87%) for WR 279,396 and 9 of 15 (60%) for Paromomycin Alone (P = 0.099). When all treated lesions were included, the final cure rate for WR 279,398-treated patients was again 87%, but the final cure rate for Paromomycin Alone-treated patients was 8 of 15 (53.3%; P = 0.046). Both creams were well tolerated with mild application site reactions being the most frequent adverse event. The increased final cure rate in the WR 279,396 group in this small Phase 2 study suggests that the combination product may provide greater clinical benefit than paromomycin monotherapy against L. panamensis cutaneous leishmaniasi
Copper interactions with DNA of chromatin and its role in neurodegenerative disorders
Get PDFIn this study, we have demonstrated the conformational changes to DNA induced by abnormal interactions of copper using circular dichroism, in combination with UV-absorbance and fluorescence spectroscopy. Results confirm that binding of copper to bases of DNA in chromatin is concentration dependent. Binding efficiency of Cu2+ ions to DNA is increased in proportion to the degree of unwinding of the double helix induced by denaturation. Altered B-DNA conformation will alter the integrity of DNA which may affect the normal process of DNA replication and transcription. Copper induced DNA damage in the brain may cause neurotoxicity and the neuronal cell death and is implicated in Alzheimer's disease and other neurological disorders.In this study, we have demonstrated the conformational changes to DNA induced by abnormal interactions of copper using circular dichroism, in combination with UV-absorbance and fluorescence spectroscopy. Results confirm that binding of copper to bases of DNA in chromatin is concentration dependent. Binding efficiency of Cu2+ ions to DNA is increased in proportion to the degree of unwinding of the double helix induced by denaturation. Altered B-DNA conformation will alter the integrity of DNA which may affect the normal process of DNA replication and transcription. Copper induced DNA damage in the brain may cause neurotoxicity and the neuronal cell death and is implicated in Alzheimer's disease and other neurological disorders
Electrical Polarization of Titanium Surfacesfor the Enhancement of Osteoblast Differentiation
Get PDFElectrical stimulation has been used clinically to promote bone regeneration in cases of fractures with delayed union or nonunion, with several in vitro and in vivo reports suggesting its beneficial effects on bone formation. However, the use of electrical stimulation of titanium (Ti) implants to enhance osseointegration is less understood, in part because of the few in vitro models that attempt to represent the in vivo environment. In this article, the design of a new in vitro system that allows direct electrical stimulation of osteoblasts through their Ti substrates without the flow of exogenous currents through the media is presented, and the effect of applied electrical polarization on osteoblast differentiation and local factor production was evaluated. A custom-made polycarbonate tissue culture plate was designed to allow electrical connections directly underneath Ti disks placed inside the wells, which were supplied with electrical polarization ranging from 100 to 500 mV to stimulate MG63 osteoblasts. Our results show that electrical polarization applied directly through Ti substrates on which the cells are growing in the absence of applied electrical currents may increase osteoblast differentiation and local factor production in a voltage-dependent manner. Bioelectromagnetics © 2013 Wiley Periodicals, IncElectrical stimulation has been used clinically to promote bone regeneration in cases of fractures with delayed union or nonunion, with several in vitro and in vivo reports suggesting its beneficial effects on bone formation. However, the use of electrical stimulation of titanium (Ti) implants to enhance osseointegration is less understood, in part because of the few in vitro models that attempt to represent the in vivo environment. In this article, the design of a new in vitro system that allows direct electrical stimulation of osteoblasts through their Ti substrates without the flow of exogenous currents through the media is presented, and the effect of applied electrical polarization on osteoblast differentiation and local factor production was evaluated. A custom-made polycarbonate tissue culture plate was designed to allow electrical connections directly underneath Ti disks placed inside the wells, which were supplied with electrical polarization ranging from 100 to 500 mV to stimulate MG63 osteoblasts. Our results show that electrical polarization applied directly through Ti substrates on which the cells are growing in the absence of applied electrical currents may increase osteoblast differentiation and local factor production in a voltage-dependent manner. Bioelectromagnetics © 2013 Wiley Periodicals, In
Bioactivity of Fungal Endophytes as a Function of Endophyte Taxonomy and the Taxonomy and Distribution of Their Host Plants
Get PDFFungal endophytes – fungi that grow within plant tissues without causing immediate signs of disease – are abundant and diverse producers of bioactive secondary metabolites. Endophytes associated with leaves of tropical plants are an especially exciting and relatively untapped source of novel compounds. However, one major challenge in drug discovery lies in developing strategies to efficiently recover highly bioactive strains. As part of a 15-year drug discovery project, foliar endophytes were isolated from 3198 plant samples (51 orders, 105 families and at least 232 genera of angiosperms and ferns) collected in nine geographically distinct regions of Panama. Extracts from culture supernatants of .2700 isolates were tested for bioactivity (in vitro percent inhibition of growth, % IG) against a human breast cancer cell line (MCF-7) and the causative agents of malaria, leishmaniasis, and Chagas’ disease. Overall, 32.7% of endophyte isolates were highly active in at least one bioassay, including representatives of diverse fungal lineages, host lineages, and collection sites. Up to 17% of isolates tested per assay were highly active. Most bioactive strains were active in only one assay. Fungal lineages differed in the incidence and degree of bioactivity, as did fungi from particular plant taxa, and greater bioactivity was observed in endophytes isolated from plants in cloud forests vs. lowland forests. Our results suggest that using host taxonomy and forest type to tailor plant collections, and selecting endophytes from specific orders or families for cultivation, will markedly increase the efficiency and efficacy of discovering bioactive metabolites for particular pharmaceutical targets.Fungal endophytes – fungi that grow within plant tissues without causing immediate signs of disease – are abundant and diverse producers of bioactive secondary metabolites. Endophytes associated with leaves of tropical plants are an especially exciting and relatively untapped source of novel compounds. However, one major challenge in drug discovery lies in developing strategies to efficiently recover highly bioactive strains. As part of a 15-year drug discovery project, foliar endophytes were isolated from 3198 plant samples (51 orders, 105 families and at least 232 genera of angiosperms and ferns) collected in nine geographically distinct regions of Panama. Extracts from culture supernatants of .2700 isolates were tested for bioactivity (in vitro percent inhibition of growth, % IG) against a human breast cancer cell line (MCF-7) and the causative agents of malaria, leishmaniasis, and Chagas’ disease. Overall, 32.7% of endophyte isolates were highly active in at least one bioassay, including representatives of diverse fungal lineages, host lineages, and collection sites. Up to 17% of isolates tested per assay were highly active. Most bioactive strains were active in only one assay. Fungal lineages differed in the incidence and degree of bioactivity, as did fungi from particular plant taxa, and greater bioactivity was observed in endophytes isolated from plants in cloud forests vs. lowland forests. Our results suggest that using host taxonomy and forest type to tailor plant collections, and selecting endophytes from specific orders or families for cultivation, will markedly increase the efficiency and efficacy of discovering bioactive metabolites for particular pharmaceutical targets