Estudio clínico citológico de pacientes con ascitis en un hospital nacional general del Perú

Objetivo. Evaluar la sensibilidad, especifcidad y valores predictivos del estudio clínico citológico de pacientes con ascitis en un hospital nacional general del Perú. Métodos. Se incluyeron pacientes que presentaron manifestaciones clínicas de ascitis, estudios bioquímicos, citológicos e histológicos. Resultados. Se estudiaron 15 pacientes con ascitis. La media de la edad fue 62 años, siendo 80 % mujeres y 20 % varones. Los diagnósticos finales revelaron diversas neoplasias malignas (93,3 %) y tuberculosis peritoneal (6,7 %). La manifestación clínica más frecuente fue dolor abdominal de grado leve a severo (80 %). Los componentes celulares fueron: hematíes (73,3 %), histiocitos (26,7 %), linfocitos (73,3 %), polimorfonucleares (40 %), células mesoteliales (86,7 %) y grupos de células epitelioides con diverso grado de atipia (80 %). Dos casos mostraron células linfoides atípicas. La sensibilidad y el valor predictivo positivo fueron del 87 % y 80 %, respectivamente. Conclusiones. De acuerdo con una prueba dicotómica, el presente estudio demuestra la alta sensibilidad y alto valor predictivo positivo del estudio clínico citológico en pacientes con ascitis.

Efecto de la ingestión de Banisteriopsis caapi y Psychotria viridis 'Binomio ayahuasca' en el hipocampo del cerebro de ratas / Effect of Banisteriopsis caapi and Psychotria viridis "Binomio ayahuasca" ingestion in the rat hippocampus

Objetivo: Evaluar el efecto de la ingestión de Banisteriopsis caapi y Psychotria viridis 'Binomio ayahuasca' en el hipocampo de cerebro de ratas. Diseño: Estudio experimental, descriptivo, analítico, transversal. Institución: Instituto de Investigación en Ciencias Farmacéuticas y Recursos Naturales, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú. Material biológico: Ratas. Intervenciones: Administración del binomio ayahuasca por vía orogástrica a ratas albinas adultas de la especie Rattus novergicus y de cepa Holtzman. A siete grupos de cinco con un peso promedio de 240 ± 30 g se les administró (GI) blanco, (GII) 2,5 mL diazepam, (GIII) 0,7 mL solución de Banisteriopsis caapi, (GIV) 0,7 mL Psychotria viridis, y a los grupos (GV), (GVI) y (GVII) se administró 0,7 mL, 3,5 mL y 7,0 mL de solución del binomio ayahuasca, respectivamente. Principales medidas de resultados: Macroscópicos: comportamiento de reflejos y actividad motora. Microscópicos: número de células piramidales y granulosas, y desorganización celular. Resultados: En el tamizaje fitoquímico del extracto se caracterizó presencia de alcaloides, antraquinonas, triterpenoides y esteroides, fenoles, flavonoides y saponinas. Los volúmenes de droga administradas a los grupos de intervención con el binomio en la dosis de 0,7 mL manifestaron significativo aumento en el número de células granulosas sobre las células piramidales; a dosis de 3,5 mL el número de células granulosas fue menor con presencia de células piramidales grandes y pequeñas; y a dosis de 7,0 mL se manifestó desorganización celular, presencia de células piramidales grandes y pequeñas, y aumento de células granulosas. Conclusiones: El extracto alcohólico del binomio ayahuasca presenta efecto neuropatológico en el hipocampo del cerebro de ratas. (AU)

One-pot nucleation, growth, morphogenesis, and passivation of 1.4 nm Au nanoparticles on self-assembled rosette nanotubes.

A one-pot strategy for the nucleation, growth, morphogenesis, and passivation of 1.4 nm Au nanoparticles (NPs) on self-assembled rosette nanotubes (RNTs) is described. Tapping-mode atomic force microscopy, transmission electron microscopy, energy-dispersive X-ray analysis, and selected-area electron diffraction were used to establish the structure and organization of this hybrid material. Notably, we found that the Au NPs formed were nearly monodisperse clusters of Au(55) (1.4-1.5 nm) nestled in pockets on the RNT surface.

Biologically inspired rosette nanotubes and nanocrystalline hydroxyapatite hydrogel nanocomposites as improved bone substitutes.

Today, bone diseases such as bone fractures, osteoporosis and bone cancer represent a common and significant public health problem. The design of biomimetic bone tissue engineering materials that could restore and improve damaged bone tissues provides exciting opportunities to solve the numerous problems associated with traditional orthopedic implants. Therefore, the objective of this in vitro study was to create a biomimetic orthopedic hydrogel nanocomposite based on the self-assembly properties of helical rosette nanotubes (HRNs), the osteoconductive properties of nanocrystalline hydroxyapatite (HA), and the biocompatible properties of hydrogels (specifically, poly(2-hydroxyethyl methacrylate), pHEMA). HRNs are self-assembled nanomaterials that are formed from synthetic DNA base analogs in water to mimic the helical nanostructure of collagen in bone. In this study, different geometries of nanocrystalline HA were controlled by either hydrothermal or sintering methods. 2 and 10 wt% nanocrystalline HA particles were well dispersed into HRN hydrogels using ultrasonication. The nanocrystalline HA and nanocrystalline HA/HRN hydrogels were characterized by x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Mechanical testing studies revealed that the well dispersed nanocrystalline HA in HRN hydrogels possessed improved mechanical properties compared to hydrogel controls. In addition, the results of this study provided the first evidence that the combination of either 2 or 10 wt% nanocrystalline HA and 0.01 mg ml(-1) HRNs in hydrogels greatly increased osteoblast (bone-forming cell) adhesion up to 236% compared to hydrogel controls. Moreover, this study showed that HRNs stimulated HA nucleation and mineralization along their main axis in a way that is very reminiscent of the HA/collagen assembly pattern in natural bone. In summary, the presently observed excellent properties of the biomimetic nanocrystalline HA/HRN hydrogel composites make them promising candidates for further study for bone tissue engineering applications.

Spectroscopically encoded microspheres for antigen biosensing.

Here, we demonstrate the potential of barcoded resins (BCRs) as a reliable platform for immunoassays. Four BCRs were synthesized by dispersion polymerization of 4-methylstyrene, t-butylstyrene, 2,4-dimethylstyrene, and 2,5-dimethylstyrene. Methacrylic acid was included in the polymerization step to provide an anchor point for antibody conjugation. In addition to identifying the BCRs through their unique spectrum in an immunoassay experiment, Raman scattering spectroscopy confirmed the immunoreactivity of the bead-conjugated antibody by detecting 150 ng/mL ( approximately 150 pg/bead) of fluorescently labeled rabbit IgG antigen. The simplicity, versatility, and effectiveness of this platform demonstrate its potential for high-throughput multiplexed bioassays.

Helical rosette nanotubes with tunable stability and hierarchy.

The design of nanostructured materials with tunable dimensions and properties that maintain their structural integrity under physiological conditions is a major challenge in biomedical engineering and nanomedicine. Helical rosette nanotubes (HRN) are a new class of materials produced through a hierarchical self-assembly process of low molecular weight synthetic organic modules in water. Here, we describe a synthetic strategy to tune their stability and hierarchy by preorganization of the self-assembling units, control of net charge per unit of nanotube surface area, amphiphilicity, and number of H-bonds per self-assembling module, and through peripheral steric (de)compression. Using these criteria, HRNs with tunable stability and hierarchical architecture were produced from self-assembling modules that (a) persist as individual molecules in solution, (b) self-assemble into HRN but denature at high temperature (<85 degrees C), (c) self-assemble into HRN whose structural integrity persists even in boiling water (>95 degrees C), and (d) self-assemble into well-dispersed short nanotubes, long nanotubes, ribbons, or superhelices. Given the biocompatibility, synthetic accessibility, and chemical and physical tunability of these materials, numerous applications in biomedical engineering, materials science, and nanoscience and technology are envisioned.

Long-range flow-induced alignment of self-assembled rosette nanotubes on Si/SiOx and poly(methyl methacrylate)-coated Si/SiOx.

Helical rosette nanotubes are obtained through the self-assembly of low molecular weight synthetic modules in water. Here we demonstrate that despite their dynamic nature, these materials respond very well to directional fluid flow and assume long-range order on flat substrates. Persistence length, order, and packing of the rosette nanotubes were found to depend dramatically on the surface properties of both the substrate and the nanotubes and vary from well-ordered long-range 2D films to bundled nanotubes or amorphous conglomerates. While flow-induced long-range alignment of dynamic nanostructures is unprecedented, the chemical tunability of the rosette nanotubes is anticipated to offer a versatile means for investigating the basis of interfacial forces in self-assembled organo-silicon devices and their effect on the stability and physical properties of organic nanostructures on electroactive surfaces.

Formation of dispersed nanostructures from poly(ferrocenyldimethylsilane-b-dimethylsiloxane) nanotubes upon exposure to supercritical carbon dioxide.

While incompatible block copolymers commonly assemble into several established classical or complex morphologies, highly asymmetric poly(ferrocenyldimethylsilane-b-dimethylsiloxane) (PFS-b-PDMS) diblock copolymers can also self-organize into high-aspect-ratio nanotubes with PDMS corona in the presence of PDMS-selective organic solvents. Exposure of these nanotubes on a carbon substrate to supercritical carbon dioxide (scCO2), also a PDMS-selective solvent, appears to promote partial dissolution of the copolymer molecules. At sufficiently high copolymer concentrations, the dissolved molecules subsequently re-organize within the scCO2 environment to form new copolymer nanostructures that redeposit on the substrate upon scCO2 depressurization. Transmission electron microscopy reveals that micelles form under all the conditions examined here, whereas nanotubes coalesce and vesicles develop only at relatively high temperatures. The extent to which the copolymer nanotubes dissolve and the size distribution of the replacement micelles are sensitive to exposure conditions. These results suggest that the phase behavior of PFS-b-PDMS diblock copolymers in scCO2 may be remarkably rich and easily tunable.

A reversible tube-to-rod transition in a block copolymer micelle.

A remarkable morphology transition occurs with a change in temperature for a diblock copolymer [poly(ferrocenyldimethylsilane-b-dimethylsiloxane) (PFS40-b-PDMS480, PDI = 1.01)] in n-decane solution. This polymer, which forms nanotubes at 25 degrees C, rearranges to form short dense rods when the solution is heated to 50 degrees C. When the solution is cooled to 25 degrees C, the system evolves back to nanotubes. These experiments demonstrate that both structures are dynamic and represent equilibrium states of the material. Contrast matching static light-scattering measurements on the short dense rods show that the insoluble PFS core is rigid and has a length distribution similar to that seen in electron microscopy images.

Efecto del jabón con Piper angustifolium R & P (matico) sobre la piel normal de conejos / Efect of Piper angustifolium R & P (matico) soap on normal rabbit skin

Objetivo: Determinar la acción de un preparado, a partir del extracto alcohólico de las hojas de Piper angustifolium R & P, bajo la forma de jabón. Material y métodos: Se utilizó un lote de conejos blancos cepa Nueva Zelanda, que fueron depilados con una crema conteniendo sales del ácido tioglicólico (Opilca); se dividieron en cuatro grupos al azar; la zona depilada del primero fue elevada con agua corriente, el segundo con los componentes del jabón básico; el tercero y el cuarto, fueron tratados con el jabón conteniendo el extracto del matico, a razón de una y dos veces, diariamente, durante 30 días. Se extrajo una porción de la piel de la zona tratada para el estudio histopatológico. Resultados: Los resultados del estudio fitoquímico indican la presencia de compuestos fenólicos y triterpenoides como metabolitos secundarios, los que serían responsables de la actividad farmacológica. Además, en el estudio histológico se observó la presencia de una capa protectora, siendo ésta más marcada en los conejos que se trataron dos veces al día durante un mes. Conclusiones: El jabón de matico mostró un efecto protector cuando fue utilizado dos veces al día en la piel de conejo.

Bulk microphase segregation of an asymmetric organometallic-inorganic diblock copolymer: a remarkable example of concentric cylinders.

We report that an asymmetric diblock copolymer, poly(ferrocenyldimethylsilane-b-dimethylsiloxane) (PFS90-b-PDMS900, PDI = 1.01, volume fraction PFS = 0.20), self-assembles in the bulk state to form a hexagonal periodic structure with a remarkable morphology. Part of the major component forms the core of concentric cylinders with a mean diameter of 35.5 nm surrounded by a 7 nm thick shell of PFS. The remaining PDMS fills the interstitial spaces. The morphology was elucidated by small-angle X-ray scattering, as well as by scanning and conventional transmission electron microscopy.

Nanotubes from the self-assembly of asymmetric crystalline-coil poly(ferrocenylsilane-siloxane) block copolymers.

Block copolymers with a high asymmetry normally give spherical starlike micelles in a solvent selective for the longer block. We have discovered that samples of poly(ferrocenyldimethylsilane-b-dimethylsiloxane) (PFS-b-PDMS) with block ratios of 1:12 form nanotubes in n-hexane and n-decane, which are poor solvents for PFS. Two block copolymer samples PFS(40)-b-PDMS(480) (M(n) = 45 300, PDI = 1.01) and PFS(80)-b-PDMS(960) (M(n) = 90 500, PDI = 1.01) were synthesized by sequential anionic polymerization. When self-assembly occurs, the PFS blocks aggregate and crystallize to form a shell with a cavity in the middle of the tube, while the PDMS blocks form the corona. The nature of these structures was elucidated by conventional transmission electron microscopy and dark-field scanning transmission electron microscopy. Time- and temperature-dependence studies revealed that a variety of morphologies are formed initially depending on the conditions of sample preparation, but most of them eventually rearrange to form nanotubules. The lengths of the tubes can be varied with time and with the choice of solvents. We have been able to grow nanotubes with lengths reaching 0.1 mm. The presence of the hollow core was confirmed by trapping tetrabutyllead in the cavity and performing energy-dispersive X-ray measurements on the resulting structure.

Concentración de pólvora para determinar la distancia de un disparo de arma de fuego / Determination of firing distance by gunpowder residue concentration analysis

Ensayar un método de diagnóstico adecuado con la medición del concentración de partículas de polvora incrustadas en los tejidos periferios al orificio de entrada (OE) para precisar la probable distancia de disparo. Usando un revolver calibre 38 con munición FAME se realizó cinco series de disparos contra fragmentos de piel de cerdo con cobertura de tela desde distancias conocidas, verificandose la presencia del tatuaje sobre la piel y la tela. Las muestras fueron microfotografiadas para cuantificar los gránulos de pólvora presentes sobre la piel. Para todas las distancias de disparo se establece un espacio claro periferico al OE, un inicio del tatuaje, una extensión del tatuaje y un final del tatuaje o zona clara postatuaje, variando esta elación de modo directamente proporcional a la distancia del disparo e inversamente a la concentración de restos de pólvora. Puede determinarse con mayor precisión la distancia aproximada de disparo, en un rango de 30 a 100 cm midiendo la concentración de partículas de pólvora incrustadas en la superficie cutánea por medio del método de microfotografía estereoscópica. Se propone el término "Tatuaje de Escarapela" para referirse a este tipo de distribución.