Síntesis y caraterización del ligando tris-(2-tiosalicilamidoetil)amina y sus complejos de hierro e indio

The coordination chemistry of the hexadentate ligand, tris(2-thiosalicylamidoethyl)amine, (LH3), was studied. The reaction of the ligand trianion with iron(III) and indium(III) yields monomeric hexacoordinate complexes, LFe·HCl and LIn. The complexes were characterized by spectroscopic, magnetic and electrochemical methods.  

Effect of pretreatment temperature on the surface modification of diatomite with trimethylchlorosilane

Artículo científicoDiatomite samples from Costa Rica were purified using acidic treatments with hydrochloric acid, thermally treated (400–1000 C) and then silylated with trimethylchlorosilane in toluene under inert atmosphere. The purification process allows to decrease the concentration of metals presented in the crude diatomite, as is confirmed by X-ray Fluorescence (XRF) Analysis. The silylated materials were analyzed by using Hyperpolarized 129Xe Nuclear Magnetic Resonance Spectroscopy (HP 129Xe NMR), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), rehydration tests, and contact angle measurements. XRD measurements indicate that diatomite is mainly amorphous, but presents several crystalline phases (kaolinite, cristobalite, and quartz). Pretreatments at high temperatures cause changes in those crystalline phases, resulting in more amorphous materials. However, there is no difference in the overall structure of purified and thermally treated diatomite samples with respect to the silylation products. In addition, SEM measurements show no effect over the pore structure of the materials. On the other hand, TGA measurements and rehydration tests show lower losses of water for silylated materials prepared using higher pretreatment temperatures. Moreover, HP 129Xe NMR, FTIR, and contact angle measurements evidence a modification due to covalent attachment of Si(CH3)3-groups to the surface, which increases for higher pretreatment temperatures. The results provide valuable information about external factors that influence the surface modification of diatomite. This can be useful to control modifications that can be achieved in a similar way

Polymers of unidimentional coordination [M(sac)2(H2O)(pyz)]n, (M= Ni2+, Cu2+ and Zn2+, sac =saccharinate, pyz= pyrazine), spectroscopy and magnetic properties

Coordination polymers have been prepared by the hydrothermal reaction of M2+saccharinates (M = Ni, Cu and Zn) and pyrazine, pyz, in a ratio 1:1. The complexes of formula [M(sac)2(H2O)2pyz]n, M = Ni2+ and Zn2+ and [Cu(sac)2(H2O)pyz]n were characterized by spectroscopic methods and elemental analysis, magnetic measurements, single and powder x-ray diffraction. The compounds crystallize in the triclinic space group p-1. The zinc ion is octahedrally coordinated by two sac ions, two water and two pyrazine molecules. The copper ion is penta-coordinated in a distorted square pyramidal geometry with the pyrazine molecules in the axial position. The metal atoms are connected via pyrazine μ-N,N’-coordination and form linear chains, containing a network of hydrogen bonds between the chains, that build a 2D sheet structure

Chromosomal defects in 34 male homosexuals, half of them with HIV antibodies

Artículo científico-- Instituto de Investigaciones en Salud--2002Most of the research about viral interactions with human chromosomes was done during the sixties and early seventies and very few was performed after the human immunodeficiency virus (HIV) appearance as an epidemic in the eighties. The objective of this work was to estimate if particular chromosomal changes follow the infection of homosexual males by HIV and to determine if the lifestyle, habits, sexual practices, of our sample of male homosexuals predisposes them to chromosomal abnormalities at a higher rate than the background level of cytogenetic damage the general population has. This was a double blinded case-control study, 17 individuals positive for HIV antibodies (HIV+) detected by enzyme-linked immunosorbent assay (ELISA) and confirmed by western blot (WB) were the cases, and 17 individuals negative for HIV antibodies (HIV-) the controls. These men were a very homogeneous population in terms of age, social status, lifestyles, drug abuse, sexual practices and education. Blood was collected between September 1988 and October 1989. Fresh whole blood was cultured in duplicate for 72 hr. Cell harvest followed conventional methods. Once all cell cultures were gathered, the tubes were picked up at random and air dried chromosome preparations were trypsin-giemsa banded (GTG) after overnight incubation at 60C'. The percentage of gaps and breaks these men had was not different from the reported for the general population, nor were there significant difference among both groups (O.R. = I .8) in terms of amount of chromosomal fragility. The distinction among them was at the level of the specific chromosomal sites where the gaps and breaks located, being sites at 2p21 and at 3p2I four times more frequent among HIV+. These probably represent viral modification sites on chromosomes which are known to look like non-staining gaps which are caused by the virus or viral products. This presumption is supported by an earlier report of repeated breaks at 3p21.1 , in fact this was the most common lesion site in this study of chromosomal aberrations of male homosexuals and the authors even considered the probability of "a new type of chromosome marker" . Furthermore, years later the CKR5 structural gene was mapped to human chromosome 3p21. This gene codes for the chemokine receptor 5 (CKR5) protein which serves as a secondary receptor on CD4+ T lymphocytes for certain strains of HIV-I. It is possible that this gene was being transcribed in HIV+ men and the consequent "staggering" of DNA contributed to the production of gaps and breaks at 3p21.En este estudio se determinaron las consecuencias citogenéticas de la infección con el virus de inmunodeficiencia humana (VIH), mediante un estudio tipo doble-ciego de casos infectados o VIH+ (N = 17) y controies VIH- (N = 17), en 34 hombres de una población muy homogénea de homosexuales, estudiada de 1988 a 1991. Se encontró fragilidad cromosómica no diferente del porcentaje informado de la población general ni diferente entre casos y controles (0.R. = 1.18). Las diferencias entre ambos grupos fueron más bien cualitativas, en los sitios de lesión cromosómica, ya que los hombres infectados mostraron cuatro veces más lesiones en dos genes en particular: 421 y 3p21. Este último coincidió con el sitio de fragilidad más común informado con anterioridad. Este sitio en 3p21 fue posteriormente identificado como el locus cromosómico donde se ubica el gen CKR5 el cual codifica para un receptor secundario en el linfocito T del VIH -1. Se propone que este gen se estaba transcribiendo activamente en los hombres infectados en los que se evidenciaron algunas fracturas cromosómicas en 3p21Universidad de Costa Rica Instituto de investigaciones en SaludUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Synthesis, characterization and redox behaviour of mixed ligand copper(II) saccharinate complexes

Three mixed-­ligand complexes of Cu(II) with saccharin (sac), pyrazole, (Hpz), imidazole, (Himid) were synthesized and characterized on the basis of elemental analysis, FT-­IR spectroscopy, magnetic susceptibility, EPR spectra, and X-­ray diffraction. The reaction of [Cu(sac)2(H2O)4] ⋅ 2H2O with pyrazol in methanol resulted in a mononuclear pentacoordinated compound [Cu(sac)2(Hpz)3] (1) and a trinuclear N,N.bridged compound [Cu3(sac)2(Hpz)3(pz)3)2(OH)] (2), forming a nine membered [-Cu-­N-­N-­]3 ring and μμ3-­‐‐OH bridge; each Cu(II) ion is tetracoordinated, with weak axial interactions from saccharinate ions.The Himidazole compound [Cu2(sac)4(Himid)4] (3) has a dinuclear structure with two saccharinate ions as bridge; each Cu(II) ions has a penta-­coordination sphere, two N-­coordinated and one O-­coordinated saccharinate ions on the equatorial plane, and two imidazole molecules in the axial positions.Se sintetizaron tres complejos de cobre(II) con una mezcla de ligandos, sacarina (sac) y pirazol (Hpz) e imidazole (Himid). Los complejos se caracterizaron por análisis elemental, espectroscopía IR-­FT, susceptibilidad magnética, esoectroscopia EPR y difracción de rayos X. La reacción de [Cu(sac)2(H2O)4] ⋅ 2H2O con pirazol en methanol produce un compuesto mononuclear pentacoordinado, [Cu(sac)2(Hpz)3] (1) y uno trinuclear [Cu3(sac)2(Hpz)3(pz)3)2(OH)] (2), con puentes N,N, que forman un anillo de nueve miembros [-­Cu-­N-­N-­]3 y un puente μμ3-­‐‐OH; cada átomo de cobre está tetracoordinado con una leve interacción axial de los iones sacarinato. El compuesto con imidazol [Cu2(sac)4(Himid)4] (3) posee una estructura dinuclear con dos iones sacarinato puente, cada átomo de cobre está pentacoordinado, con dos iones sacarinatos unidos por el átomo de nitrógeno y uno unido por un átomo de oxígeno en el plano equatorial y dos moléculas de imidazol en la posición axial

Biochemical characterization of extracellular polymeric substances from endodontic biofilms.

Apical periodontitis is frequently associated with the presence of bacteria biofilm, which has an indisputable impact on the prognosis of endodontic therapy due to the high resistance to adverse environmental conditions, chemicals, and antibiotic therapy that characterize bacteria within biofilm. The biofilm matrix acts as a protective shield over the encased microorganisms. The aim of this investigation was to identify the main biochemical components of biofilm matrix from endodontic mono- and dual-species biofilms. Enterococcus faecalis and Actinomyces naeslundii were cultured as mono- and dual-species biofilms for 14 days. Crude extracellular polymeric substances (EPSs) from biofilm matrices were extracted using chemical and physical methods. High-performance liquid chromatography, gas chromatography, and mass spectrometry were used to determine the carbohydrate, protein, and fatty acid components. Chemical analysis of the biofilm matrices revealed that they were mainly composed of stachyose, maltose, and mannose carbohydrates. The protein profile in all biofilm samples showed abundant oxidoreductases and chaperone proteins and some virulence- associated proteins mainly located in the membrane surface. High percentages of saturated and monounsaturated fatty acids were identified in all biofilm matrices, with a major prevalence of palmitic, stearic, and oleic acids. Based on the results, it was possible to obtain for the first time a general overview of the biochemical profile of endodontic biofilm matrices

Karyotypes in pregnancy losses, frst 31 cases studied in Costa Rica

El Laboratorio ha recibido 31 muestras de restos de abortos desde 2005. Para 24 casos se tiene información acerca de la semana de edad gestacional en que se tomó la muestra. Todos los casos fueron pérdidas gestacionales tempranas, excepto uno con 26 semanas de embarazo. El promedio de edad gestacional para los casos de abortos tempranos fue de 8 semanas y 6 días. Todas las muestras tenían algún grado de contaminación bacteriana. Sin embargo, de 31, solamente no se lograron cultivos celulares en 7 muestras muy contaminadas. La tasa de fracaso de los cultivos fue, por lo tanto, del 22%. De los 24 cariotipos obtenidos, 15 fueron 46, XX, 3 fueron 46, XY y 6 resultaron anormales, para un 25% de cromosomopatía en estas muestras. Es posible que el porcentaje de cromosomopatía encontrado esté subestimado, debido a la contaminación de las muestras con células maternas. El tiempo promedio de respuesta del Laboratorio, para el 90 % de los casos, fue de 24 días.The laboratory has received 31 samples of abortion material since 2005. For 24 cases, we have information about the gestational age at which the sample was taken. All cases were an early pregnancy loss except for one with 26 weeks of pregnancy. The average gestational age for cases of early abortion was 8 weeks and 6 days. All samples had some degree of bacterial contamination. However, out of 31 samples, we failed to obtain cell cultures only in 7 due to high contamination. Therefore, the failure rate of the cultures was 22%. Out of the 24 karyotypes obtained, 15 were 46, XX, 3 were 46, XY and 6 were abnormal, for a 25% of chromosome aberrations in these samples. It is possible that the percentage of abnormal chromosomes found is underestimated due to sample contamination with maternal cells. For 90% of cases, the average turn around time of the laboratory was 24 days.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

One Hundred Accredited Fetal Karyotypes in Costa Rica During 2009 and 2010

Objetivo: La identificación de cromosomopatía fetal es un factor importante para el mejor manejo perinatal y pediátrico en los embarazos de alto riesgo. El objetivo de esta publicación es mostrar al personal de salud, los resultados de nuestros ensayos de cariotipo en líquido amniótico, obtenidos desde el momento en que han sido acreditados por el Ente Costarricense de Acreditación y compararlos con los estándares internacionales. Métodos: Se realizó cultivo abierto de 100 muestras recibidas desde enero del 2009 hasta diciembre 2010, provenientes de hospitales de la seguridad social y de servicios de salud privados y la cosecha de los “amniocitos” mediante suspensión enzimática. La indicación de amniocentesis en el 65% de los casos fue por ecografía anormal y el 28% de las veces por edad materna avanzada. Resultados: La cromosomopatía fetal encontrada fue de 35%. Para muestras en cantidad y calidad aceptables, el éxito de los cultivos fue 100% y el tiempo de respuesta fue de 13 días promedio. Estos datos concuerdan con las normas internacionales en esta materia. Además, anualmente participamos satisfactoriamente en rondas de evaluación externa de la calidad organizados por la Cytogenetic European Quality Assessment. Conclusión: En Costa Rica contamos con servicios de perinatología con equipos ecográficos muy sofisticados y con personal altamente especializado, de manera que los defectos anatómicos fetales y otras patologías rara vez pasan desapercibidas. El cariotipo fetal es el complemento indispensable para el abordaje clínico óptimo de estos casos, sobre todo, cuando se cuenta con la calidad que garantizan los ensayos acreditados.Aims: The identification of fetal abnormal chromosomes in high risk pregnancies, allows proper pediatric and obstetric management of the cases as well as genetic counseling. The results of 100 genetic amniocentesis from January 2009 to December 2010, since the accreditation of these laboratory tests, are reported. Methods: Amniocentesis were performed in hospitals of the social security system and in private facilities. There were two main reasons for referral: abnormal ultrasound assessment (65% of cases) and advanced maternal age (28%). Fetal cells were flask open cultured and suspension harvested. Results: Abnormal fetal karyotypes were 35%. Success rate for samples of acceptable quality was 100%. Turn around time was 13 days average. This data is in accordance with American and European requirements for quality and competence. The laboratory also participates annually in Cytogenetic European Quality Assessment rounds with achievements of satisfactory performance. Conclusion: In Costa Rica we have skilled and experienced perinatologists as well as highly sophisticated ultrasonographic equipment, so that many fetal and pregnancy abnormalities are routinely detected. In these cases, the fetal karyotype of guaranteed quality is a very useful tool in their adequate clinical management.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Raman Spectroscopic Characterization of Endodontic Biofilm Matrices

Endodontic persistent infections are often mediated by bacterial biofilms. This mode of bacterial growth is characterized by the presence of a matrix mainly composed of extracellular polymeric substances (EPSs) that protect the encased microorganisms. To establish better control and disinfection protocols, elucidation of the main components of biofilm matrices present in endodontic infections is required. The aim of the present study was to characterize the principal components of E. faecalis, A. naeslundii, and dual-species biofilm matrices by means of Raman spectroscopy and confocal scanning laser microscopy (CSLM) techniques. The total biomass of biofilms was quantified via crystal violet assays, and the monospecies biofilms showed higher biomass than the dual-species biofilms. Raman spectroscopy and confocal laser scanning microscopy were used to identify the biochemical composition and structure of the biofilm matrices. Spectra originating from the biofilms of two endodontic pathogens show the presence of carbohydrates, proteins, fatty acids, and nucleic acids in all samples; however, variation in the levels of expression of these biomolecules allows spectroscopic differentiation of the biofilms using principal component analysis. This study is the first attempt to identify the composition of monospecies and dual-species biofilms of endodontic origin. Our data provides an important approach to the understanding of molecular dynamics of endodontic infections

Synthesis, structure and spectroscopic characterization of Ni(II), Co(II), Cu(II) and Zn(II) complexes with saccharinate and pyrazole

Four mononuclear mixed-ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II), with saccharin (sac) and pyrazole (Hpz) were synthesized and characterized on the basis of elemental analysis, FT-IR spectroscopy, magnetic susceptibility, thermal analysis data and X-ray diffraction. The [Co(sac)2(Hpz)2(H2O)2] (1) and [Ni(sac)2(Hpz)2(H2O)2] (2) had similar molecular structures but distinct monoclinic crystal structure types (space group P21/n for 1 and P21/c for 2); the members of each pair of ligands were mutually trans. The saccharinate ligands were N-coordinated. The copper complex showed the same coordination environment as the Co and Ni complexes but crystallizes in the triclinic space group P1 and presented pseudo-Jahn–Teller distortion along the O(w)–Cu–O(w) bonds. The [Zn(sac)2(pz)2] complex was tetrahedrally coordinated and crystallized in the monoclinic space group C2/c. Thermal decomposition of the complexes in a nitrogen atmosphere resulted in removal of the water molecules and pyrazole ligands at relatively low temperature and formation of stable metal saccharinates as intermediates, which also decomposed at higher temperatures, about 300 C. 2007 Elsevier Ltd. All rights reserved.Universidad de Costa Rica/[115-98-375]/UCR/Costa RicaMinistery of Science and Technology/[BQU2002-00554]//EspañaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic