Quantification of nucleobases/gold nanoparticles interactions: energetics of the interactions through apparent binding constants determination.

We explore the possibilities of quantifying the interaction of both adenine and thymine with non-functionalized, anionic citrate gold nanoparticles (AuNPs). Following the plasmon absorbance band's red shifts, dependent of the AuNPs aggregation state, apparent binding free energies of the system are obtained for the sum of the two processes (nucleobase interaction plus nanoparticle aggregation). A deconvolution procedure confirms those results. Those apparent binding free energies are, in both cases, in good agreement with previous studies indicating an increased reactivity for adenine. Moreover, density functional theory (DFT) calculations were carried out both to model the structures and to theoretically support and help understand the observed experimental stability of adenine as compared to thymine over gold nanoparticles. Theoretical results indicate the N atom in the amino group of adenine adopts a pyramidal sp3 hybridization character, stabilizing the interaction with Au as compared to thymine.

Free energy of binding of cationic metal complexes to AuNPs through electron-transfer processes.

AuNP effects on the oxidation reaction of [Ru(NH3)5pz](2+) with S2O8(2-) were studied. Experimental results show the effects produced by gold nanoparticles of different sizes, which are then discussed by using an approach based on the two-state model. Changes in the observed reactivity are explained by a change in the degree of association of the reactants to the nanoclusters, which depends on the negative surface potential of the gold nanoparticles. TEM and zeta potential measurements show that this potential determines the binding strength of one of the reactants ([Ru(NH3)5pz](2+)) to the citrate gold surface. The number of binding sites on a citrate nanoparticle receptor has also been determined. The experimental results confirm that an electron transfer reaction can be used as a probe for the determination of the free energy of binding of cationic metal complexes to gold nanoparticles.

[Pseudoaneurysm in the radial artery after catheterization]. / Seudoaneurisma de arteria radial post-canulación.

Eleven days after surgery to remove an olfactory groove meningioma, a woman developed a pulsatile swelling and localized elevation of temperature in the radial artery catheterized to monitor arterial pressure. Pseudoaneurysm of the radial artery was diagnosed and the patient was returned to the operating room for ligation and biopsy of the vessel under regional anesthesia. Her condition worsened in spite of the resection and 48 hours after repair of the arterial pseudoaneurysm she was admitted to the intensive care unit with septic shock. Radial artery catheterization is a safe, frequently performed procedure but it is not free of risk. The most common complication is thrombosis. Much more rare are pseudoaneurysms, lesions that are observed late after catheterization (7-40 days) and are associated with vessel wall alterations, repeated puncture attempts, and catheter infection. The usual therapeutic approach involves surgical resection and ligature of the vessel, although other measures have been suggested.

A functional BH3 domain in an aquaporin from Leishmania infantum.

Despite the absence of sequences showing significant similarity to any of the members of the Bcl-2 family of proteins in protozoa, experiments carried out in yeast or trypanosomatids have demonstrated that ectopic expression of some of these members alters their response to different death stimuli. Because the BH3 domain is the smallest common signature in all the proteins of this family of apoptosis regulators and also because they are essential for molecular interactions between antagonistic members, we looked for sequences with significant similarity to the BH3 motif in the Leishmania infantum genome. Among the top scoring ones, we found the MYLALQNLGDEV amino-acid stretch at the C terminus of a previously described aquaporin, now renamed as Li-BH3AQP. This motif is highly conserved in homologous proteins from other species of the Leishmania genus. The association of Li-BH3AQP with human Bcl-XL was demonstrated by both co-immunoprecipitation and yeast two-hybrid experiments. Ectopic expression of Li-BH3AQP reduced viability of HeLa cells and this deleterious effect was abrogated by the simultaneous overexpression of Bcl-XL. Although we were not able to demonstrate a reduction in parasite viability when the protein was overexpressed in Leishmania promastigotes, a prodeath effect could be observed when the parasites overexpressing Li-BH3AQP were treated with staurosporine or antimycin A. Surprisingly, these parasites were more resistant, compared with wild-type parasites, to hypotonic stress or nutrient deprivation. The prodeath activity was abolished upon replacement of two highly conserved amino acids in this BH3 domain. Taken together, these results point to Li-BH3AQP as the first non-enzymatic protein ever described in trypanosomatids that is involved in cell death.

The expression of the Leishmania infantum KMP-11 protein is developmentally regulated and stage specific.

Transcription of the gene coding for the KMP-11 protein of Leishmania infantum results in the production of a mature RNA transcript of 1.3 kb in length. The expression of KMP-11 mRNA is strongly down-regulated not only during the parasite growth from the logarithmic to the stationary phase but also during the differentiation transit from promastigotes to amastigotes. The estimated concentration of KMP-11 is one order of magnitude higher in promastigotes than in amastigotes. The analysis of the Triton X-114 phase partition of the protein shows that, in agreement with its predicted secondary structure, KMP-11 has an amphipathic nature since it is found in the aqueous as well as in the detergent phase. By fluorescence microscopy a defined pattern of distribution of the protein was observed only in promastigotes where KMP-11 is mainly located in the flagellum and the flagellar pocket.

Electrogenerated chemiluminescence reactions between the [Ru(bpy)3](2+) complex and PAMAM GX.0 dendrimers in an aqueous medium.

Electrogenerated chemiluminescence, ECL, reactions between tris(2,2'-bipyridine)ruthenium(II), [Ru(bpy)3](2+), and PAMAM GX.0 (X=1 and 2) dendrimers in an aqueous medium were carried out at pH10 (fully deprotonated dendrimer surface). ECL was detected in the presence of GX.0 dendrimers without addition of any known coreactant. Atomic force microscopy, AFM, measurements for GX.0 dendrimers in the presence of the [Ru(bpy)3](2+) complex were also done. AFM images showed the existence of aggregates (pillars) of globular shape, as well as interdendrimer networks forming fibers in the x-y direction for dendrimer aqueous solutions. ECL and AFM results in cooperation suggest that the coreactant effect of the end amine groups is improved by both the dendritic branched shells and the globular z-type aggregates. The ECL efficiency trends as a function of [GX.0] (whole range) can be interpreted taking into account the coreactant effect modulated by the presence of the z and x-y type aggregates. Importantly, ECL efficiency values can be taken as a measure of the change induced on the dendrimer aggregation in aqueous solutions when their concentrations rise. Redox potentials of the [Ru(bpy)3](3+/2+) couple in the presence of the G1.0 and G2.0 dendrimers were also determined.

Sequence and expression of the Drosophila phenylalanine hydroxylase mRNA.

We report the cloning, nucleotide (nt) sequence and expression of the cDNA (pah) encoding phenylalanine hydroxylase (PAH) of Drosophila melanogaster. The strong hybridization signals observed in genomic blots when D. melanogaster DNA was probed with 32P-labeled human pah cDNA, indicated the existence of a high degree of sequence similarity between the pah genes of both species. The length of the pah genomic fragment is about 30 to 40 kb. The cDNA contains 84 bp of the 5'-untranslated region, 1359 bp of the protein-coding region and 87 bp of the 3' region, with only one polyadenylation signal. The isolated cDNA is probably full-length, since the size of the D. melanogaster PAH mRNA is 1.5 kb. At the nt level, the similarity of the D. melanogaster cDNA with human and rat pah cDNAs is 57.9% and 58.1%, respectively. The highest similarities are restricted to the nt sequence coding for the presumed hydroxylation domain. There is no nt sequence similarity between the first three exons of the human pah gene and an equivalent fraction of the D. melanogaster pah gene. At the amino acid (aa) level, the similarity in the presumed hydroxylation domain is 88.5%, in which two motifs of the structure AGLLSSXXXL are found, where X represents any aa. It was interesting to notice the conservation of aa 408, 311 and 280, where mutations are associated with phenylketonuria in humans. We observed, moreover, that, as it occurs in humans and rats, the expression of the D. melanogaster pah gene is tissue-specific and temporally regulated.

Characterization of a highly repeated interspersed DNA sequence of Trypanosoma cruzi: its potential use in diagnosis and strain classification.

In the present paper we report the characterization of a repetitive DNA sequence from the genome of the Maracay strain of Trypanosoma cruzi. The sequence is 1025 nucleotides long and represent about 7% of the total nuclear DNA of the parasite with a copy number of 1-2 x 10(4) copies per genome. It is also present in a high copy number in several strains of T. cruzi but absent from other trypanosomatids and from the human genome. The DNA sequence is interspersed and present on many chromosomes. We show that the different copies of this repeat present extensive endonuclease restriction polymorphisms. Using 2 conserved oligonucleotide primers derived from the repetitive sequence, together with the polymerase chain reaction technique, the presence of less than 1/30 of a single parasite can be readily detected by ethidium bromide staining.

Regulation of hsp70 expression in Trypanosoma cruzi by temperature and growth phase.

The steady-state level of the hsp70 mRNAs of Trypanosoma cruzi cultured at different temperatures and growth conditions has been analyzed by Northern blotting. We show that only one size class of hsp70 mRNA, of about 2.2 kb, is transcribed from the hsp70 cluster and that its transcription is constitutive at 28 degrees C. However, after a heat shock treatment at 37 degrees C for 2 h of logarithmically growing parasites, the abundance of the hsp70 mRNA increased about 4-fold. A similar increase was observed at 28 degrees C when the parasite culture reached the stationary phase of growth. On the other hand, a heat shock at 42 degrees C did not change the steady state level of the 2.2-kb size class of hsp70 mRNA. However, accumulation of transcripts of high molecular weight was detected when stationary growing parasites were cultured at 42 degrees C for 2 h. Also at 37 degrees C the steady state level of the alpha- and beta-tubulin mRNAs of logarithmically growing parasites exhibited a slight increase but only after a period of 24 h. Analysis by one-dimensional immunoblots of the Hsp70 levels showed that at 37 degrees C the abundance of the protein was 4-fold higher than at 28 degrees C. Immunoblots of high-resolution two-dimensional gel electrophoresis showed, moreover, that various isoforms of this protein are constitutively expressed at 28 degrees C and that some of them have a specific pattern of induction at 37 degrees C. We observed, moreover, that the heat shock induces the expression of a series of proteins while it causes repression of others.

DNA binding properties and antileukemic (L1210) activity of a Pt-pentamidine complex.

The DNA thermal stabilizing effect and the antileukemic properties of a Pt-pentamidine complex have been studied. The results indicate that the pentamidine ligands in Pt-pentamidine probably have an interaction with the DNA stronger than that of pentamidine alone because they are bound to the nucleic acid through the cis-PtCl2 residues. However, the cis-PtCl2 residues do not seem to significantly destabilize the helix. Two types of evidences are consistent with this hypothesis: (1) a decrease in the dielectric constant of the medium does not remove the pentamidine ligands from the Pt-pentamidine: DNA complex, and (2) the renaturation of the DNA in Pt-pentamidine:DNA complex is DNA concentration independent. 1H- and 13C-NMR spectroscopic data together with the elemental analysis indicate that the complex is a stoichiometric oligomer of formula [(cis-PtCl2)3(pentamidine)3] [PtCl4]2. This drug exhibits significant antineoplastic activity in BDF1 mice bearing i.p. L1210 leukemia. At a concentration of 50 mg/kg, about 15% of the LD50 for the 1,5 and 9 days schedule, the antitumor activity (T/C = 337%) is considerably superior to that of cis-DDP (T/C = 215%) or carboplatin (T/C = 220%) at doses representing 75% and 50%, respectively, of the LD50 for the same treatment schedule. Moreover, it was found that the nephro-hepatotoxicity of the complex is low.

Encefalitis autoinmunitaria secundaria a teratoma ovárico: un nuevo síndrome neuropsiquiátrico. Reporte de caso / Autoimmune encephalitis secondary to ovarian teratoma: a new neuropsychiatric syndrome. Report of one case

Resumen ANTECEDENTES: los síndromes neurológicos paraneoplásicos son trastornos asociados con neoplasias, casi siempre por autoanticuerpos producidos por el propio tumor, que causan autoinmunidad cruzada con antígenos en el sistema nervioso central. Hace poco se describió una nueva enfermedad neuropsiquiátrica en mujeres jóvenes con teratoma ovárico, que producen anticuerpos en contra del receptor de N-metil-D-aspartato, que es parte de los diferentes tipos de encefalitis límbicas. CASO CLÍNICO: paciente de 20 años de edad, con un cuadro neuropsiquiátrico prominente con diagnóstico final de encefalitis límbica por anticuerpos anti rNMDA secundaria a teratoma ovárico, con remisión total del cuadro neurológico después del tratamiento multimodal. CONCLUSIÓN: en nuestro conocimiento es el primer caso reportado de encefalitis límbica anti rNMDA debida a teratoma ovárico, con remisión completa del cuadro después del tratamiento multimodal con cirugía, inmunosupresión e inmunomodulación.

Abstract BACKGROUND: paraneoplastic neurological syndromes are disorders associated with neoplasias, generally from autoantibodies produced by the tumor itself that cause crossed immunity with antigens in the central nervous system. A new neuropsychiatric disease was described recently in young women with ovarian teratoma that produce antibodies against the N-methyl-D-aspartate receptor that is part of the spectrum of limbic encephalitis. CLINICAL CASE: 20 year old patient with a significant neuropsychiatric picture with a final diagnosis of limbic encephalitis from anti rNMDA antibodies secondary to ovarian teratoma, and total remission of the neurological picture after multimodal treatment. CONCLUSION: to our knowledge it is the first case of anti rNMDA limbic encephalitis due to ovarian teratoma reported with complete remission of the picture after multimodal treatment with surgery, immunosuppression and immunomodulation.

Heat-induced programmed cell death in Leishmania infantum is reverted by Bcl-X(L) expression.

An increasing number of reports indicate that single-celled organisms are able to die following what seems to be an ordered program of cell death with strong similarities to apoptosis from higher eukaryotes. DNA degradation and several other apoptotic-like processes have also been described in the parasitic protozoa Leishmania. However, the existence of an apoptotic death in this parasite is still a matter of controversy. Our results indicate that most of the processes of macromolecular degradation and organelle dysfunction observed in mammalian cells during apoptosis can also be reproduced in promastigotes of the genus Leishmania when incubated at temperatures above 38 degrees C. These processes can be partially reversed by the expression of the anti-apoptotic mammalian gene Bcl-X(L), which suggests that this family of apoptosis-regulating proteins was present very early in the evolution of eukaryotic cells.

Nivel de conocimientos de los adolescentes sobre el Virus de Inmunodeficiencia Humana/Síndrome de Inmunodeficiencia Adquirida / Level of knowledge among adolescents on the Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome

El Programa Conjunto de las Naciones Unidas informó que 33.3 millones de personas en el mundo vivían con el VIH a finales del 2009. En México existen 200,000 personas con el VIH/SIDA. En el sureste mexicano, Oaxaca ocupa el cuarto lugar de casos de SIDA principalmente en los adolescentes. La disciplina de enfermería puede abordar este problema a través de la promoción y prevención de la enferme - dad en los adolescentes que residen en zonas rurales. Objetivo: Identificar el nivel de conocimientos que tienen los adolescentes hijos de padres migrantes acerca del VIH/SIDA de una comunidad rural oaxaqueña. Metodología. El estudio fue transversal, descriptivo. La muestra fue de 37 adolescentes ambos sexos hijos de padres migrantes. La ética del estudio consideró el Reglamento de la Ley General de Salud. Resultados: El 91.2% de la muestra presentó conocimientos regulares, el 2.9% conocimientos adecuados y el 5.9% no adecuados. Discusión y conclusión: Los resultados coinciden con otras investigaciones, sin embargo la mayor parte de éstas se han realizado en un contexto urbano, lo que ha limitado la prevención del VIH/SIDA en zonas rurales. El estudio, permitió evidenciar problemas que pueden ser abordados, por la disciplina de enfermería.

The United Nation Joint Program of the United Nations Organization to inform that 33.3 millions of persons in the world lived with VIH to the end of 2009. In México exist 200,000 persons with VIH/SIDA. Oaxaca hold the fourth position of case of SIDA in the southeast in adolescents. The discipline of nursing can broach this problem through it promotion and prevention of the disease in the adolescents that to lie in place zone rurals. Objective. To identify the level of knowledge that to have the adolescents children's of parents migrants about the one VIH/SIDA of a community rural of Oaxaca. Methodology. The study were descriptive transverse. The simple were of 37 adolescents both sexs. Children´s of parents migrants. The ethic of study to considers the Rules Health General Law of México. Results. The 91.2% of sample to present knowledge regulars; the 2.9% knowledge good and the 5.9% knowledge bads. Discussion and conclusion. The results to coincide with others researchs. However the majority part of these to them the used in a context urban, this to limited prevention of VIH/SIDA in zones rurals. The adolescents had Knowledge regulars and the study to permit to demonstrate problems that can be broach by the discipline of nursing.

In vivo binding of trimethylpsoralen detects DNA structural alterations associated with transcribing regions in the human beta-globin cluster.

In order to increase our knowledge about the mechanisms that regulate expression of human beta-like globin genes, we have used a novel technique to analyze the chromatin structure in living cells. This approach allowed us to detect specific DNA regions in vivo where nucleosome folding or unconstrained DNA supercoiling in erythroid cells differs from that in non-erythroid cells. In this method, we use 4,5',8-trimethylpsoralen (TMP) as a probe capable of detecting altered chromatin conformations. Our results show that TMP binds to DNA with a higher affinity over the regions in the locus that are actively expressed, including both the promoter and the transcribed region. This higher affinity detected when comparing erythroid cells with non-erythroid cells does not extend to other regions inside the beta-globin cluster. Our data suggest that the observed effect is likely due to nucleosome displacement. Alternatively, it could result from localized DNA supercoiling, but not from widespread torsional stress across the entire beta-like globin locus as hypothesized previously.

Leucine rich repeats are the main epitopes in Leishmania infantum PSA during canine and human visceral leishmaniasis.

The PSA protein is one of the major antigens of the surface of the Leishmania infantum parasite membrane. We describe the immune humoral response against the PSA in dogs and human patients with visceral leishmaniasis caused by L. infantum. The immunodominant region of the PSA was determined by subcloning, expression and purification of three fragments covering the complete protein. The analysis revealed that the antibodies are mostly directed against the central region, which is formed exclusively by leucine rich repeats. This region is recognized by 100% of the sera from the infected dogs and 40% of the human sera. These percentages are significantly higher than those observed when the complete protein was used as antigen. The analysis of the isotype of the G immunoglobulins raised against the immunodominant determinants of the PSA indicates that both IgG1 and IgG2 classes are produced during natural infections but that the IgG2 predominates over that of the IgG1.