Migration of HIV infected individuals from cities to small towns and rural areas spreads AIDS amo... more Migration of HIV infected individuals from cities to small towns and rural areas spreads AIDS among non urban population, superimposing HIV with other endemic or epidemic infections as parasitoses. This situation is a big challenge to public health because in most cases the association between these infections worsens both prognoses. We present here the first case in Argentina of AIDS associated to a mucocutaneous form of American tegumentary leishmaniasis. The patient was from Orán, an area where in the middle eighties, an epidemic outbreak took place. By now more than 2000 cases have been parasitologically confirmed in our Institute and the causing species were identified as Leishmania (V.) braziliensis and L. (L.) amasonensis. Considering the existence of co-infection of HIV and Leishmania, it is recommended that in patients from endemic areas with records of cutaneous or mucocutaneous ulcers, even healed, leishmaniasis must be investigated, among other diseases.
ABSTRACT Heterochromatin is the highly compacted form of chromatin with various condensation leve... more ABSTRACT Heterochromatin is the highly compacted form of chromatin with various condensation levels hallmarked by high DNA methylation. MeCP2 is mostly known as a DNA methylation reader but has also been reported as a heterochromatin organizer. Here, we combine liquid–liquid phase separation (LLPS) analysis and single-molecule tracking with quantification of local MeCP2 concentrations in vitro and in vivo to explore the mechanism of MeCP2-driven heterochromatin organization and dynamics. We show that MeCP2 alone forms liquid-like spherical droplets via multivalent electrostatic interactions and with isotropic mobility. Crowded environments and DNA promote MeCP2 LLPS and slow down MeCP2 mobility. DNA methylation, however, restricts the growth of heterochromatin compartments correlating with immobilization of MeCP2. Furthermore, MeCP2 self-interaction is required for LLPS and is disrupted by Rett syndrome mutations. In summary, we are able to model the heterochromatin compartmentalization as well as MeCP2 concentration and heterogeneous motion in the minimal in vitro system.
Introduccion: El bajo peso al nacer es un problema de salud publica mundial, recien nacidos prete... more Introduccion: El bajo peso al nacer es un problema de salud publica mundial, recien nacidos pretermino bajo peso al nacer, hospitalizados en unidades neonatales, requieren para su manejo profesionales de salud actualizados, que conozcan los factores que contribuyen a la ganancia eficiente de peso. Objetivo: Identificar los factores predictores de la madre, del neonato y las intervenciones que contribuyen a la ganancia eficiente de peso, y las comorbilidades que influyen en la no ganancia ponderal, en neonatos pretermino con bajo peso al nacer hospitalizados en la UCI neonatal. Materiales y metodos: Se conformo una cohorte retrospectiva con neonatos pretermino, de 30-36.6 semanas de edad gestacional, pesos 1000-1800 gramos atendidos en un Hospital de Segundo Nivel en Bogota. Se realizo un analisis en 3 etapas. Primera etapa: se evaluo integridad de la informacion, se calcularon frecuencias de exposicion y no exposicion. Segunda etapa: analisis bivariado, para evaluar asociacion entre...
: Collaboration between Space and Naval Warfare Systems Center Pacific (SSC Pacific) and the Nava... more : Collaboration between Space and Naval Warfare Systems Center Pacific (SSC Pacific) and the Naval Research Lab (NRL) was initiated in 2015 and 2016 as part of the OSD Quantum Science and Engineering Program (QSEP). The collaborations topic is to examine the effect of an electric-field on silicon carbide qubits as a unique contribution, as well as a general benefit in increasing knowledge in the quantum information field and working towards supporting demonstrations of quantum entanglement based on these qubits and quantum memories developed out of the silicon carbide system and other systems as necessary through the QSEP program. This years highlights included successful completion of a novel process flow for the construction of the tunable qubits, measurements of the optical emission from the devices, simulations of the tuning process, and progress for experimental validation of the concepts and for supporting entanglement demonstrations. A patent disclosure was filed on the conce...
En el presente trabajo se lleva a cabo una evaluacion de la sostenibilidad de la deuda publica en... more En el presente trabajo se lleva a cabo una evaluacion de la sostenibilidad de la deuda publica en Venezuela. En la primera parte del estudio se presenta un breve bosquejo teorico de los modelos para evaluar la sostenibilidad de la deuda publica que aparece reflejado en la literatura economica. Asimismo, se presenta la evolucion de los indicadores de sostenibilidad de la deuda publica, asi como una comparacion internacional de los niveles de deuda de Venezuela en comparacion con otros paises de la region. Se observa que aunque los indicadores tradicionales de deuda publica no indican un peso importante de la deuda sobre la economia nacional, al estudiar la trayectoria de endeudamiento actual, se concluye que el endeudamiento publico no es sostenible en el tiempo.
This study aims to determine whether the stock performance of a company affects the frequency of ... more This study aims to determine whether the stock performance of a company affects the frequency of events associated with mergers and acquisitions in Latin America. In order to determine this hypothesis, companies with a consistently poor stock performance (for a period of three years) were identified for a selected number of countries in the region. Subsequently, companies with the lowest decile, in terms of stock returns were compared with the best performing decile, in order to analyze whether there is a higher incidence of events of mergers and acquisitions in the sample of firms with poor performance. The results showed that the highest number of mergers and acquisitions events occurred more frequently in the lowest decile, so a mediocre performance of the stock of the company affects the frequency of events associated with mergers and acquisitions in the sample studied for the period 2005- 2009 in Latin America.
: This technical report presents simulation and experimental hardware development of pulsed modul... more : This technical report presents simulation and experimental hardware development of pulsed modulated microwave/radio frequency electronic control circuitry for control of electron/nuclear spin states of qubits/quantum memory applicable to semiconductor, superconductor, ionic and superconductor-ionic hybrid technologies. As the pulse quality and need for development of single pulses with very high quality will impact directly the coherence time of the qubit/memory, we present as an example the integration of cryogenic superconductor components including filters and amplifiers to improve the pulse quality and validate the approach. Control of qubits/quantum memory using this technology will be subject of future report.
La neumonía es causa importante de morbimortalidad en la infancia. La diferenciación entre las ba... more La neumonía es causa importante de morbimortalidad en la infancia. La diferenciación entre las bacterianas y las que no lo son puede generar dificultades para el clínico. La escala de Laura Moreno combina aspectos clinicos, radiológicos y de laboratorio con una sensibilidad de1100% y especificidad del 93.9%, en el diagnóstico de neumonía bacteriana. Objetivo: describir la concordancia observada en el diagnóstico de neumonía bacteriana, al aplicar una escala de predicción aplicada por el pediatra y el radiólogo comparada con el diagnostico clínico, en los pacientes del servicio de pediatría del Hospital de San José. Metodología: se estudiaron niños con edades que variaron entre un mes y cinco años, hospitalizados con diagnóstico de neumonía en el periodo del 1° de septiembre al 30 de noviembre de 2007. Se analizaron 73 pacientes que cumplieron los criterios de inclusión. Resultados: según el diagnóstico clínico 52 pacientes tenían NB, 18 neumonía viral y tres no fueron clasificados a...
RarA is a widely conserved protein proposed to be involved in recombination-dependent replication... more RarA is a widely conserved protein proposed to be involved in recombination-dependent replication. We present a cell biological approach to identify functional connections between RarA and other proteins using single molecule tracking. We found that 50% of RarA molecules were static, mostly close to replication forks and likely DNA-bound, while the remaining fraction was highly dynamic throughout the cells. RarA alternated between static and dynamic states. Exposure to H2O2 increased the fraction of dynamic molecules, but not treatment with mitomycin C or with methyl methanesulfonate, which was exacerbated by the absence of RecJ, RecD2, RecS and RecU proteins. The ratio between static and dynamic RarA also changed in replication temperature-sensitive mutants, but in opposite manners, dependent upon inhibition of DnaB or of DnaC (pre)primosomal proteins, revealing an intricate function related to DNA replication restart. RarA likely acts in the context of collapsed replication forks,...
Bacillus subtilis AddAB, RecS, RecQ, PcrA, HelD, DinG, RecG, RuvAB, PriA and RecD2 are genuine re... more Bacillus subtilis AddAB, RecS, RecQ, PcrA, HelD, DinG, RecG, RuvAB, PriA and RecD2 are genuine recombinational repair enzymes, but the biological role of RecD2 is poorly defined. A ΔrecD2 mutation sensitizes cells to DNA-damaging agents that stall or collapse replication forks. We found that this ΔrecD2 mutation impaired growth, and that a mutation in the pcrA gene (pcrA596) relieved this phenotype. The ΔrecD2 mutation was not epistatic to ΔaddAB, ΔrecQ, ΔrecS, ΔhelD, pcrA596 and ΔdinG, but epistatic to recA. Specific RecD2 degradation caused unviability in the absence of RecG or RuvAB, but not on cells lacking RecU. These findings show that there is notable interplay between RecD2 and RecG or RuvAB at arrested replication forks, rather than involvement in processing Holliday junctions during canonical double strand break repair. We propose that there is a trade-off for efficient genome duplication, and that recombinational DNA helicases directly or indirectly provide the cell with ...
Migration of HIV infected individuals from cities to small towns and rural areas spreads AIDS amo... more Migration of HIV infected individuals from cities to small towns and rural areas spreads AIDS among non urban population, superimposing HIV with other endemic or epidemic infections as parasitoses. This situation is a big challenge to public health because in most cases the association between these infections worsens both prognoses. We present here the first case in Argentina of AIDS associated to a mucocutaneous form of American tegumentary leishmaniasis. The patient was from Orán, an area where in the middle eighties, an epidemic outbreak took place. By now more than 2000 cases have been parasitologically confirmed in our Institute and the causing species were identified as Leishmania (V.) braziliensis and L. (L.) amasonensis. Considering the existence of co-infection of HIV and Leishmania, it is recommended that in patients from endemic areas with records of cutaneous or mucocutaneous ulcers, even healed, leishmaniasis must be investigated, among other diseases.
ABSTRACT Heterochromatin is the highly compacted form of chromatin with various condensation leve... more ABSTRACT Heterochromatin is the highly compacted form of chromatin with various condensation levels hallmarked by high DNA methylation. MeCP2 is mostly known as a DNA methylation reader but has also been reported as a heterochromatin organizer. Here, we combine liquid–liquid phase separation (LLPS) analysis and single-molecule tracking with quantification of local MeCP2 concentrations in vitro and in vivo to explore the mechanism of MeCP2-driven heterochromatin organization and dynamics. We show that MeCP2 alone forms liquid-like spherical droplets via multivalent electrostatic interactions and with isotropic mobility. Crowded environments and DNA promote MeCP2 LLPS and slow down MeCP2 mobility. DNA methylation, however, restricts the growth of heterochromatin compartments correlating with immobilization of MeCP2. Furthermore, MeCP2 self-interaction is required for LLPS and is disrupted by Rett syndrome mutations. In summary, we are able to model the heterochromatin compartmentalization as well as MeCP2 concentration and heterogeneous motion in the minimal in vitro system.
Introduccion: El bajo peso al nacer es un problema de salud publica mundial, recien nacidos prete... more Introduccion: El bajo peso al nacer es un problema de salud publica mundial, recien nacidos pretermino bajo peso al nacer, hospitalizados en unidades neonatales, requieren para su manejo profesionales de salud actualizados, que conozcan los factores que contribuyen a la ganancia eficiente de peso. Objetivo: Identificar los factores predictores de la madre, del neonato y las intervenciones que contribuyen a la ganancia eficiente de peso, y las comorbilidades que influyen en la no ganancia ponderal, en neonatos pretermino con bajo peso al nacer hospitalizados en la UCI neonatal. Materiales y metodos: Se conformo una cohorte retrospectiva con neonatos pretermino, de 30-36.6 semanas de edad gestacional, pesos 1000-1800 gramos atendidos en un Hospital de Segundo Nivel en Bogota. Se realizo un analisis en 3 etapas. Primera etapa: se evaluo integridad de la informacion, se calcularon frecuencias de exposicion y no exposicion. Segunda etapa: analisis bivariado, para evaluar asociacion entre...
: Collaboration between Space and Naval Warfare Systems Center Pacific (SSC Pacific) and the Nava... more : Collaboration between Space and Naval Warfare Systems Center Pacific (SSC Pacific) and the Naval Research Lab (NRL) was initiated in 2015 and 2016 as part of the OSD Quantum Science and Engineering Program (QSEP). The collaborations topic is to examine the effect of an electric-field on silicon carbide qubits as a unique contribution, as well as a general benefit in increasing knowledge in the quantum information field and working towards supporting demonstrations of quantum entanglement based on these qubits and quantum memories developed out of the silicon carbide system and other systems as necessary through the QSEP program. This years highlights included successful completion of a novel process flow for the construction of the tunable qubits, measurements of the optical emission from the devices, simulations of the tuning process, and progress for experimental validation of the concepts and for supporting entanglement demonstrations. A patent disclosure was filed on the conce...
En el presente trabajo se lleva a cabo una evaluacion de la sostenibilidad de la deuda publica en... more En el presente trabajo se lleva a cabo una evaluacion de la sostenibilidad de la deuda publica en Venezuela. En la primera parte del estudio se presenta un breve bosquejo teorico de los modelos para evaluar la sostenibilidad de la deuda publica que aparece reflejado en la literatura economica. Asimismo, se presenta la evolucion de los indicadores de sostenibilidad de la deuda publica, asi como una comparacion internacional de los niveles de deuda de Venezuela en comparacion con otros paises de la region. Se observa que aunque los indicadores tradicionales de deuda publica no indican un peso importante de la deuda sobre la economia nacional, al estudiar la trayectoria de endeudamiento actual, se concluye que el endeudamiento publico no es sostenible en el tiempo.
This study aims to determine whether the stock performance of a company affects the frequency of ... more This study aims to determine whether the stock performance of a company affects the frequency of events associated with mergers and acquisitions in Latin America. In order to determine this hypothesis, companies with a consistently poor stock performance (for a period of three years) were identified for a selected number of countries in the region. Subsequently, companies with the lowest decile, in terms of stock returns were compared with the best performing decile, in order to analyze whether there is a higher incidence of events of mergers and acquisitions in the sample of firms with poor performance. The results showed that the highest number of mergers and acquisitions events occurred more frequently in the lowest decile, so a mediocre performance of the stock of the company affects the frequency of events associated with mergers and acquisitions in the sample studied for the period 2005- 2009 in Latin America.
: This technical report presents simulation and experimental hardware development of pulsed modul... more : This technical report presents simulation and experimental hardware development of pulsed modulated microwave/radio frequency electronic control circuitry for control of electron/nuclear spin states of qubits/quantum memory applicable to semiconductor, superconductor, ionic and superconductor-ionic hybrid technologies. As the pulse quality and need for development of single pulses with very high quality will impact directly the coherence time of the qubit/memory, we present as an example the integration of cryogenic superconductor components including filters and amplifiers to improve the pulse quality and validate the approach. Control of qubits/quantum memory using this technology will be subject of future report.
La neumonía es causa importante de morbimortalidad en la infancia. La diferenciación entre las ba... more La neumonía es causa importante de morbimortalidad en la infancia. La diferenciación entre las bacterianas y las que no lo son puede generar dificultades para el clínico. La escala de Laura Moreno combina aspectos clinicos, radiológicos y de laboratorio con una sensibilidad de1100% y especificidad del 93.9%, en el diagnóstico de neumonía bacteriana. Objetivo: describir la concordancia observada en el diagnóstico de neumonía bacteriana, al aplicar una escala de predicción aplicada por el pediatra y el radiólogo comparada con el diagnostico clínico, en los pacientes del servicio de pediatría del Hospital de San José. Metodología: se estudiaron niños con edades que variaron entre un mes y cinco años, hospitalizados con diagnóstico de neumonía en el periodo del 1° de septiembre al 30 de noviembre de 2007. Se analizaron 73 pacientes que cumplieron los criterios de inclusión. Resultados: según el diagnóstico clínico 52 pacientes tenían NB, 18 neumonía viral y tres no fueron clasificados a...
RarA is a widely conserved protein proposed to be involved in recombination-dependent replication... more RarA is a widely conserved protein proposed to be involved in recombination-dependent replication. We present a cell biological approach to identify functional connections between RarA and other proteins using single molecule tracking. We found that 50% of RarA molecules were static, mostly close to replication forks and likely DNA-bound, while the remaining fraction was highly dynamic throughout the cells. RarA alternated between static and dynamic states. Exposure to H2O2 increased the fraction of dynamic molecules, but not treatment with mitomycin C or with methyl methanesulfonate, which was exacerbated by the absence of RecJ, RecD2, RecS and RecU proteins. The ratio between static and dynamic RarA also changed in replication temperature-sensitive mutants, but in opposite manners, dependent upon inhibition of DnaB or of DnaC (pre)primosomal proteins, revealing an intricate function related to DNA replication restart. RarA likely acts in the context of collapsed replication forks,...
Bacillus subtilis AddAB, RecS, RecQ, PcrA, HelD, DinG, RecG, RuvAB, PriA and RecD2 are genuine re... more Bacillus subtilis AddAB, RecS, RecQ, PcrA, HelD, DinG, RecG, RuvAB, PriA and RecD2 are genuine recombinational repair enzymes, but the biological role of RecD2 is poorly defined. A ΔrecD2 mutation sensitizes cells to DNA-damaging agents that stall or collapse replication forks. We found that this ΔrecD2 mutation impaired growth, and that a mutation in the pcrA gene (pcrA596) relieved this phenotype. The ΔrecD2 mutation was not epistatic to ΔaddAB, ΔrecQ, ΔrecS, ΔhelD, pcrA596 and ΔdinG, but epistatic to recA. Specific RecD2 degradation caused unviability in the absence of RecG or RuvAB, but not on cells lacking RecU. These findings show that there is notable interplay between RecD2 and RecG or RuvAB at arrested replication forks, rather than involvement in processing Holliday junctions during canonical double strand break repair. We propose that there is a trade-off for efficient genome duplication, and that recombinational DNA helicases directly or indirectly provide the cell with ...
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Papers by Hector Romero