Solid Dispersion of Ursolic Acid in Gelucire 50/13: a Strategy to Enhance Drug Release and Trypanocidal Activity

Solid dispersions (SDs) are an approach to increasing the water solubility and bioavailability of lipophilic drugs such as ursolic acid (UA), a triterpenoid with trypanocidal activity. In this work, Gelucire 50/13, a surfactant compound with permeability-enhancing properties, and silicon dioxide, a drying adjuvant, were employed to produce SDs with UA. SDs and physical mixtures (PMs) in different drug/carrier ratios were characterized and compared using differential scanning calorimetry, hot stage microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size, water solubility values, and dissolution profiles. Moreover, LLC-MK2 fibroblast cytotoxicity and trypanocidal activity evaluation were performed to determine the potential of SD as a strategy to improve UA efficacy against Chagas disease. The results demonstrated the conversion of UA from the crystalline to the amorphous state through XRD. FTIR experiments provided evidence of intermolecular interactions among the drug and carriers through carbonyl peak broadening in the SDs. These findings helped explain the enhancement of water solubility from 75.98 μg/mL in PMs to 293.43 μg/mL in SDs and the faster drug release into aqueous media compared with pure UA or PMs, which was maintained after 6 months at room temperature. Importantly, improved SD dissolution was accompanied by higher UA activity against trypomastigote forms of Trypanosoma cruzi, but not against mammalian fibroblasts, enhancing the potential of UA for Chagas disease treatment.Key words: Chagas disease, Gelucire 50/13, solid dispersions, solvent evaporation method, ursolic acid     

Contribution to the diatom flora of Cambodia: Five new recent freshwater taxa

Cambodian aquatic ecosystems are extremely diversified and constitute major preservation targets.However,the species composition,diversity,and distribution of the inhabiting algal communities are large...     

Use of RAPD patterns for clone verification and in studying provenance relationships in Norway spruce (Picea abies)

 We have used the RAPD technique to analyse samples of Picea abies obtained from an improvement forestry station. Two types of plant material were harvested, the first being clones and the second provenances from various regions. We first checked the clonal identity of elite tree cuttings and clones; some differences in the RAPD patterns resulting from mis-planting or mis-labelling of cuttings were found. We also established a reference library of RAPD fingerprints for 96 clones, which will serve as a reference source in cases of litigation concerning clone identity. The RAPD technique was also used to study the genetic relationship between nine European provenances of Norway spruce. A dendogram was obtained by individual pairwise comparison of 42 RAPD bands, which separated the nine provenances into two major groups, one containing the Nordic provenances (Sweden and Bielorussia) and another the Alpine provenances (France, Austria, Germany and Belgium). The Belgian provenance, which is not indigenous, is most closely related to the German provenance. We conclude that the RAPD technique is a useful tool for forestry stations in managing propagation operations. Received: 15 June 1996 / Accepted: 11 October 1996     

Genetic alterations in poorly differentiated and undifferentiated thyroid carcinomas

Thyroid gland presents a wide spectrum of tumours derived from follicular cells that range from well differentiated, papillary and follicular carcinoma (PTC and FTC, respectively), usually carrying a good prognosis, to the clinically aggressive, poorly differentiated (PDTC) and undifferentiated thyroid carcinoma (UTC).It is usually accepted that PDTC and UTC occur either de novo or progress from a pre-existing well differentiated carcinoma through a multistep process of genetic and epigenetic changes that lead to clonal expansion and neoplastic development. Mutations and epigenetic alterations in PDTC and UTC are far from being totally clarified. Assuming that PDTC and UTC may derive from well differentiated thyroid carcinomas (WDTC), it is expected that some PDTC and UTC would harbour genetic alterations that are typical of PTC and FTC. This is the case for some molecular markers (BRAF and NRAS) that are present in WDTC, PDTC and UTC. Other genes, namely P53, are almost exclusively detected in less differentiated and undifferentiated thyroid tumours, supporting a diagnosis of PDTC or, much more often, UTC. Thyroid-specific rearrangements RET/PTC and PAX8/PPARγ, on the other hand, are rarely found in PDTC and UTC, suggesting that these genetic alterations do not predispose cells to dedifferentiation. In the present review we have summarized the molecular changes associated with the two most aggressive types of thyroid cancer.     

Quantitative variation of the sesquiterpene lactones and chromenes of encelia farinosa

The components of the two major classes of natural products of the composite Encelia farinosa, sesquiterpene lactones and benzopyrans/benzofurans (chromenes), were resolved and quantified by high performance liquid chromatography. Geographic variation was examined over a range of mesic and xeric populations from California and Arizona (USA). The concentration of farinosin, a sesquiterpene lactone, varies significantly between individuals and seasonally within individuals. Ontogenetic comparisons revealed interpopulation variations within sesquiterpene lactones and chromenes. A geographic survey suggests the presence of two putative chemical races which vary in the amounts of sesquiterpene lactones and chromenes present. The adaptive significance of this quantitative variation is discussed.     

Ultrastructural immunolocalization of elastic fibers in rat blood vessels using the protein A-gold technique

Identification of elastic fibers at the ultrastructural level is accomplished by a post-embedding immunohistochemical technique using the protein A-colloidal gold method. Antisera against elastins from human dermis and rat aorta have been characterized by radioimmunoassay and then applied to thin sections of rat blood vessels. Two fixative solutions and two embedding media have been tested. Both antibodies bind to elastic fibers of normal arteries and veins, indicating crossreactions among organs and species. The high sensitivity of this method is demonstrated by its application to the detection of neo-elastogenesis in the intimal thickening of aortic grafts.     

Genetic analysis of autoimmune sialadenitis in nonobese diabetic mice: a major susceptibility region on chromosome 1

The nonobese diabetic (NOD) mouse strain provides a good study model for Sj?gren's syndrome (SS). The genetic control of SS was investigated in this model using different matings, including a (NOD x C57BL/6 (B6))F(2) cross, a (NOD x NZW)F(2) cross, and ((NOD x B6) x NOD) backcross. Multiple and different loci were detected depending on parent strain combination and sex. Despite significant complexity, two main features were prominent. First, the middle region of chromosome 1 (chr.1) was detected in all crosses. Its effect was most visible in the (NOD x B6)F(2) cross and dominated over that of other loci, including those mapping on chr.8, 9, 10, and 16; the effect of these minor loci was observed only in the absence of the NOD haplotype on chr.1. Most critically, the chr.1 region was sufficient to trigger an SS-like inflammatory infiltrate of salivary glands as shown by the study of a new C57BL/6 congenic strain carrying a restricted segment derived from NOD chr.1. Second, several chromosomal regions were previously associated with NOD autoimmune phenotypes, including Iddm (chr.1, 2, 3, 9, and 17, corresponding to Idd5, Idd13, Idd3, Idd2, and Idd1, respectively), accounting for the strong linkage previously reported between insulitis and sialitis, and autoantibody production (chr.10 and 16, corresponding to Bana2 and Bah2, respectively). Interestingly, only two loci were detected in the (NOD x NZW)F(2) cross, on chr.1 in females and on chr.7 in males, probably because of the latent autoimmune predisposition of the NZW strain. Altogether these findings reflect the complexity and heterogeneity of human SS.     

Preliminary assays indicate that Antonia ovata (Loganiaceae) and Derris amazonica (Papilionaceae), ichthyotoxic plants used for fishing in Roraima,Brazil, have an insecticide effect on Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae)

Laboratory-reared Lutzomyia longipalpis (Lutz and Neiva 1912) was tested with extracts of two ichthyotoxic plants, known as timbós, used as fishing poison in the Amazon. Phlebotomines, L. longipalpis, and plants, Antonia ovata and Derris amazonica, were collected in the Raposa-Serra do Sol Indian Reserve, a focus of visceral leishmaniasis in the State of Roraima, Brazil. Extracts were prepared from dried leaves of A. ovata and roots of D. amazonica that were percolated in water, filtered and dried out at 50 degrees C. The solid extract obtained was diluted in water at 150, 200 and 250 mg/ml. The solution was blotted in filter paper placed at the bottom of cylindric glass tubes containing sand flies. For each plant extract and dilution, two series of triplicates with 5 male and 5 female specimens of L. longipalpis were used. Mortality was recorded every 2 h during 72 h of exposure. At 72 h the mortality was as high as 80% for extracts of A. ovata (LD50 = 233 mg/ ml), and 100% for D. amazonica (LD50 = 212 mg/ ml) whereas in the control groups maximum mortality never surpassed 13%. Preliminary assays indicated that A. ovata and D. amazonica displayed significant insecticide effect against L. longipalpis.     

A Long-Term Experimental Study Demonstrates the Costs of Begging That Were Not Found over the Short Term

Parent–offspring conflict theory predicts that begging behaviour could escalate continuously over evolutionary time if it is not prevented by costliness of begging displays. Three main potential physiological costs have been proposed: growth, immunological and metabolic costs. However, empirical evidence on this subject remains elusive because published results are often contradictory. In this study, we test for the existence of these three potential physiological costs of begging in house sparrow (Passer domesticus) nestlings by stimulating a group of nestlings to beg for longer and another group for shorter periods than in natural conditions. All nestlings were fed with the same quantity of food. Our study involves a long-term experimental treatment for begging studies (five consecutive days). Long-term studies frequently provide clearer results than short-term studies and, sometimes, relevant information not reported by the latter ones. Our long-term experiment shows (i) a clear effect on the immune response even since the first measurement (6 hours), but it was higher during the second (long-term) than during the first (short-term) test; (ii) evidence of a growth cost of begging in house sparrow nestlings not previously found by other studies; (iii) body condition was affected by our experimental manipulation only after 48 hour; (iv) a metabolic cost of begging never previously shown in any species, and (v) for the first time, it has shown a simultaneous effect of the three potential physiological costs of begging: immunocompetence, growth, and metabolism. This implies first, that a multilevel trade-off can occur between begging and all physiological costs and, second, that a lack of support in a short-term experiment for the existence of a tested cost of begging does not mean absence of that cost, because it can be found in a long-term experiment.     

Overexpression of the <Emphasis Type="Italic">Arabidopsis</Emphasis> anaphase promoting complex subunit <Emphasis Type="Italic">CDC27a</Emphasis> increases growth rate and organ size

The Anaphase Promoting Complex (APC) controls CDK activity by targeting the ubiquitin-dependent proteolysis of S-phase and mitosis-promoting cyclins. Here, we report that the ectopic expression of the Arabidopsis CDC27a, an APC subunit, accelerates plant growth and results in plants with increased biomass production. CDC27a overexpression was associated to apical meristem restructuration, protoplasts with higher ³H-thimidine incorporation and altered cell-cycle marker expression. Total protein extracts immunoprecipitated with a CDC27a antibody showed ubiquitin ligase activity, indicating that the Arabidopsis CDC27a gets incorporated into APC complexes. These results indicate a role of AtCDC27a in regulation of plant growth and raise the possibility that the activity of the APC and the rates of plant cell division could be regulated by the concentration of the CDC27a subunit. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Cristian Antonio Rojas and Nubia Barbosa Eloy contributed equally to this work.