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2.
Acta bioquím. clín. latinoam ; 55(4): 439-443, dic. 2021. graf
Artigo em Espanhol | LILACS, BINACIS | ID: biblio-1393747

RESUMO

Resumen El objetivo del trabajo fue analizar los valores de hemoglobina glucosilada en el tercer trimestre de embarazo como predictores alternativos de la diabetes gestacional en pacientes del Noreste de México. Se trata de un estudio retrospectivo de casos y controles a partir de 121 expedientes de pacientes embarazadas, divididos en dos grupos, pacientes con diabetes gestacional (casos) y gestantes con valores glucémicos normales (controles). Se analizaron los factores de riesgo asociados a la diabetes gestacional y se obtuvo un punto de corte para la hemoglobina glucosilada. Se encontró que la obesidad materna, la edad y el antecedente del padecimiento fueron asociados significativamente con la diabetes gestacional. Valores de hemoglobina glucosilada ≥5% incrementaron el riesgo de padecer diabetes mellitus gestacional 4 veces y, aunado a un factor de riesgo, la probabilidad se incrementó 7 veces. Se concluye que los valores de hemoglobina glucosilada en el tercer trimestre de embarazo podrían emplearse como prueba diagnóstica de la diabetes gestacional en pacientes del Noreste de México. Sin embargo, aunque las diferencias encontradas fueron estadísticamente significativas, los resultados se deben interpretar con cautela y requieren su confirmación con estudios que incluyan una muestra mayor.


Abstract The objective of this study was to analise glycosylated hemoglobin values in the third trimester of pregnancy as an alternative predictor of gestational diabetes in North East Mexican cohort patients. This is a retrospective case-control study based on 121 records of pregnant patients, divided into two groups, patients with gestational diabetes (cases) and pregnant women with normal glycemic values (control). The risk factors associated with gestational diabetes were analised and a cut-off point for glycosylated hemogestaglobin was obtained. It was found that maternal obesity, age and a history of the condition were significantly associated with gestational diabetes. Values of glycosylated hemoglobin ≥5% increased the risk of suffering from gestational diabetes 4 times, and coupled with a risk factor, the risk increased 7 times. It is concluded that glycosylated hemoglobin values in the third trimester of pregnancy could be used as a diagnostic test for gestational diabetes in patients from the North East of Mexico. Although the differences found were statistically significant, our results must be interpreted with caution and require confirmation by studies with a larger sample.


Resumo O objetivo deste estudo foi analisar os valores da hemoglobina glicada no terceiro trimestre de gestação como preditores alternativos do diabetes gestacional em pacientes na região nordeste do México. Trata-se de um estudo retrospectivo de casos e controles utilizando 121 prontuários de gestantes divididas em dois grupos; pacientes com diabetes gestacional (casos) e gestantes com valores de glicemia normais (controles). Foram analisados os fatores de risco associados a diabetes gestacional obtendo-se um ponto de corte para a hemoglobina glicada. Descobriu-se que a obesidade materna, idade e antecedentes da doença foram associados significativamente ao diabetes gestacional. Valores da hemoglobina glicada ≥ 5% aumentaram o risco de padecer diabetes mellitus gestacional 4 vezes, e juntamente a um fator de risco, a probabilidade aumentou 7 vezes. Conclui-se que os valores da hemoglobina glicada no terceiro trimestre de gestação poderiam ser usados como teste diagnóstico do diabetes gestacional em pacientes da região nordeste do México. Embora as diferenças encontradas tenham sido estatisticamente significativas, os resultados devem ser interpretados com cautela e requerem confirmação através de estudos que incluam uma amostra maior.


Assuntos
Humanos , Feminino , Adulto , Terceiro Trimestre da Gravidez , Hemoglobinas Glicadas , Diabetes Gestacional/diagnóstico , Mulheres , Estudos de Casos e Controles , Probabilidade , Fatores de Risco , Técnicas e Procedimentos Diagnósticos , Corte , Gestantes , Testes Diagnósticos de Rotina , Transtornos do Metabolismo dos Lipídeos , Obesidade Materna
3.
Biochim Biophys Acta Biomembr ; 1863(10): 183665, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34097861

RESUMO

We report a theoretical and experimental study on a new series of small-sized antibacterial peptides. Synthesis and bioassays for these peptides are reported here. In addition, we evaluated different physicochemical parameters that modulate antimicrobial activity (charge, secondary structure, amphipathicity, hydrophobicity and polarity). We also performed molecular dynamic simulations to assess the interaction between these peptides and their molecular target (the membrane). Biophysical characterization of the peptides was carried out with different techniques, such as circular dichroism (CD), linear dichroism (LD), infrared spectroscopy (IR), dynamic light scattering (DLS), fluorescence spectroscopy and TEM studies using model systems (liposomes) for mammalian and bacterial membranes. The results of this study allow us to draw important conclusions on three different aspects. Theoretical and experimental results indicate that small-sized peptides have a particular mechanism of action that is different to that of large peptides. These results provide additional support for a previously proposed four-step mechanism of action. The possible pharmacophoric requirement for these small-sized peptides is discussed. Furthermore, our results indicate that a net +4 charge is the adequate for 9 amino acid long peptides to produce antibacterial activity. The information reported here is very important for designing new antibacterial peptides with these structural characteristics.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/síntese química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Dicroísmo Circular , Interações Hidrofóbicas e Hidrofílicas , Estrutura Secundária de Proteína
4.
Chemphyschem ; 21(12): 1258-1271, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32352214

RESUMO

The thermoresponsive nature of aqueous solutions of poly(N-isopropylacrylamide) (PNIPAAM) star polymers containing 2, 3, 4, and 6 arms has been investigated by turbidity, dynamic light scattering, rheology, and rheo-SALS. Simulations of the thermosensitive nature of the single star polymers have also been conducted. Some of the samples form aggregates even at temperatures significantly below the lower critical solution temperature (LCST) of PNIPAAM. Increasing concentration and number of arms promotes associations at low temperatures. When the temperature is raised, there is a competition between size increase due to enhanced aggregation and a size reduction caused by contraction. Monte Carlo simulations show that the single stars contract with increasing temperature, and that this contraction is more pronounced when the number of arms is increased. Some samples exhibit a minimum in the turbidity data after the initial increase at the cloud point. The combined rheology and rheo-SALS data suggest that this is due to a fragmentation of the aggregates followed by re-aggregation at even higher temperatures. Although the 6-arm star polymer aggregates more than the other stars at low temperatures, the more compact structure renders it less prone to aggregation at temperatures above the cloud point.

5.
Ginecol. obstet. Méx ; 87(4): 228-233, ene. 2019. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1250026

RESUMO

Resumen OBJETIVO: Estimar la incidencia de infecciones en pacientes que finalizaron el embarazo por cesárea e identificar los factores de riesgo asociados antes y después de la implementación de un programa preventivo. MATERIALES Y MÉTODOS: Estudio cuantitativo, no experimental, de cohorte prospectiva. Se seleccionaron mujeres que finalizaron el embrazo por cesárea en el Hospital Universitario de Saltillo, entre octubre de 2015 a octubre de 2016. Se practicaron tres medidas preventivas para disminuir el riesgo de infecciones poscesárea: administración profiláctica de antibiótico, lavado vaginal preoperatorio con yodopovidona y retiro del catéter urinario al término de la cirugía. Al séptimo día del alta hospitalaria se citó a las pacientes para evaluar la posibilidad de infección de la herida quirúrgica, endometritis o sepsis. Para el análisis estadístico se utilizó el programa SPSS versión 21. Se consideró estadísticamente significativo el valor de p < 0.05. RESULTADOS: Se registraron 103 pacientes. La incidencia de infección de la herida quirúrgica, fue de 1.9% y de dehiscencia 1%; no se registraron casos de endometritis. Al comparar la incidencia de infecciones poscesárea, previo al protocolo (año 2015) y posterior a la implementación de las medidas preventivas, se demostró la disminución de infección de la herida quirúrgica (2.4 a 1.9%) y de endometritis (1.9 a 0%). CONCLUSIÓN: La implementación del programa preventivo de infecciones poscesárea, basado en la administración profiláctica de antibiótico, lavado vaginal con yodopovidona y retiro de la sonda urinaria temprana, disminuye el índice de infecciones puerperales poscesárea.


Abstract OBJECTIVE: An estimates the incidence and risk factors associated with infections in caesarean sections before and after the implementation of the preventive program. MATERIALS AND METHODS: Non-experimental quantitative study of a prospective cohort type. The study population were women they finished the pregnancy by caesarean section during the period of october 2015 to october 2016. Three preventive measures were performed to reduce the risk of postoperative infections: prophylactic antibiotic, preoperative vaginal lavage with iodopovidone and urinary catheter removal at the end of the surgery a follow-up was performed at 7 days identifying patients with infected wound, endometritis and sepsis. The results will be analyzed using the SSPS software versión 21. RESULTS: A total of 103 women were incorporated into the protocol. The incidence of postoperative infections was 1.9% for wound infections, 1.0% dehiscence and 0% endometritis. A comparative analysis was performed of incidences of surgical site infection, endometritis, sepsis and surgical wound dehiscence, prior to the preventive protocol (year 2015) and after the implementation of preventive measures, and we observed a reduction of endometritis from 1.9% to 0% and of the surgical wound infection from 2.4% to 1.9%. CONCLUSION: The preventive program integrated by the use of prophylactic antibiotic, preoperative vaginal lavage with iodopovidone and urinary catheter removal at the end of surgery, reduced the rate of post-cesarean puerperal infections.

6.
ACS Omega ; 3(5): 5390-5398, 2018 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-30221230

RESUMO

The first stage of the action mechanism of small cationic peptides with antimicrobial activity is ruled by electrostatic interactions between the peptide and the pathogen cell membrane. Thus, an increase in its activity could be expected with an increase in the positive charge on the peptide. By contrast, the opposite behavior has been observed when the charge increases to reach a critical value, beyond which the activity falls. This work studies the perturbation effects in a cell membrane model for two small cationic peptides with similar length and morphology but with different cationic charges. The synthesis and antibacterial activity of the two peptides used in this study are described. The thermodynamic study associated with the insertion of these peptides into the membrane and the perturbing effects on the bilayer structure provide valuable insights into the molecular action mechanism associated with the charge of these small cationic peptides.

7.
Int J Mol Sci ; 19(7)2018 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-29937518

RESUMO

The LrtA protein of Synechocystis sp. PCC 6803 intervenes in cyanobacterial post-stress survival and in stabilizing 70S ribosomal particles. It belongs to the hibernating promoting factor (HPF) family of proteins, involved in protein synthesis. In this work, we studied the conformational preferences and stability of isolated LrtA in solution. At physiological conditions, as shown by hydrodynamic techniques, LrtA was involved in a self-association equilibrium. As indicated by Nuclear Magnetic Resonance (NMR), circular dichroism (CD) and fluorescence, the protein acquired a folded, native-like conformation between pH 6.0 and 9.0. However, that conformation was not very stable, as suggested by thermal and chemical denaturations followed by CD and fluorescence. Theoretical studies of its highly-charged sequence suggest that LrtA had a Janus sequence, with a context-dependent fold. Our modelling and molecular dynamics (MD) simulations indicate that the protein adopted the same fold observed in other members of the HPF family (ß-α-ß-ß-ß-α) at its N-terminal region (residues 1­100), whereas the C terminus (residues 100­197) appeared disordered and collapsed, supporting the overall percentage of overall secondary structure obtained by CD deconvolution. Then, LrtA has a chameleonic sequence and it is the first member of the HPF family involved in a self-association equilibrium, when isolated in solution.


Assuntos
Proteínas de Bactérias/química , Proteínas Ribossômicas/química , Ribossomos/química , Synechocystis/química , Motivos de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Simulação de Dinâmica Molecular , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Estabilidade Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Ribossomos/metabolismo , Soluções , Synechocystis/metabolismo , Termodinâmica
8.
Ginecol. obstet. Méx ; 86(3): 165-173, feb. 2018. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-984415

RESUMO

Resumen OBJETIVO Evaluar si la prescripción de ácido tranexámico a pacientes con síndrome de HELLP mejora su curso clínico en forma general. MATERIALES Y MÉTODOS Estudio retrospectivo, analítico y comparativo al que se incluyeron dos grupos de pacientes con diagnóstico de síndrome de HELLP atendidas entre enero de 2015 y diciembre de 2016 en el servicio de Ginecología y Obstetricia del Hospital Universitario de Saltillo. A un grupo se le indicó ácido tranexámico y al control ningún medicamento. RESULTADOS Se incluyeron 18 pacientes, 9 en cada grupo. Parámetros de laboratorio: plaquetas mayores a 105 vs menores a 105 en el grupo control. La deshidrogenasa láctica (DHL) tuvo un decremento de 58 vs 16% en las pacientes tratadas en las primeras 48 horas. La aspartato aminotransferasa (TGO) mejoró 56 vs 43% en el grupo control y la alanina aminotransferasa (TGP) mejoró 31 vs 20% en el grupo control, ambas en las primeras 24 horas. La cuantificación de proteínas en orina en 24 horas reportó 2867 mg versus 3378 mg en el grupo control. La hemoglobina permaneció siempre en cifras superiores a 11 vs 9.92 g/dL del grupo control. Los días de estancia en la unidad de cuidados intensivos fue de 3 vs 4.16 del grupo control. CONCLUSIONES Hacen falta más estudios con asignación al azar, con una muestra más amplia, para valorar las ventajas y efectos del ácido tranexámico en pacientes con síndrome de HELLP. La prescripción de este medicamento representa una alternativa en el tratamiento del síndrome de HELLP, que proporciona un beneficio clínico.


Abstract OBJECTIVE To stablish if the use of tranexamic acid (TXA) in patients with HELLP syndrome improves the clinic curse in general terms. MATERIALS AND METHODS Analytic, comparative and retrospective study where two groups of patients are included, which assisted to the obstetrics and gynecology service in the Hospital Universitario de Saltillo, where the diagnosis of HELLP syndrome was made. Tranexamic acid was given to one of the groups versus the control group without the drug. RESULTS 18 patients were included, 9 in each group. The following was observed respect to the laboratory parameters: platelets greater than 105 vs smaller than 105 in the control group. The lactate dehydrogenase (DHL) had a decrease of 58 vs 16% in the patients without tranexamic acid in the first 48 hours. The aspartate aminotransferase (AST) improved 56 vs 43% in the control group, and the alanine aminotransferase (ALT) improved 31 vs 20% in the control group, both in the first 24 hours. The report of protein quantification in 24 hours was 2867 vs 3378 mg in the control group. The hemoglobin figures remained greater than 11vs 9.92 g/dL of the control group. The days of stay in the intensive care unit (UCI) were 3 vs 4.16 of the control group. CONCLUSIONS: Randomized studies are required with an extended sample, to value the benefits and effects of the tranexamic acid, in this kind of patients. According to the collected data the use of tranexamic acid represents an alternative in the treatment of HELLP syndrome, which provides a clinic benefit.

9.
Ginecol. obstet. Méx ; 86(5): 342-350, feb. 2018. graf
Artigo em Espanhol | LILACS | ID: biblio-984441

RESUMO

Resumen ANTECEDENTES La extracción de un mioma, posterior a la resección laparoscópica, puede ser: directa, mediante colpotomía posterior, minilaparotomía, morcelación intraabdominal estándar o eléctrica. La mayor parte de estas opciones suele requerir la colocación de un trocar de 10-12 mm o la ampliación de la incisión en la piel y fascia para extraer el tejido; esto implica desventajas estéticas y clínicas, como el riesgo de hernias incisionales. CASOS CLÍNICOS Se comunican tres casos de pacientes con diagnóstico de miomatosis de grandes elementos (7 cm el menor y 15 cm el mayor) en los que posterior a la miomectomía por laparoscopia se extrae la pieza quirúrgica íntegra mediante colpotomía posterior, con evolución posquirúrgica favorable y sin síntomas concomitantes. CONCLUSIÓN La extracción transvaginal mediante colpotomía posterior es una alternativa segura y efectiva para retirar piezas quirúrgicas porque la elasticidad de la vagina permite extraer de forma segura piezas grandes, y evitar así el uso del morcelador y sus posibles riesgos. Además, se evita ampliar las incisiones abdominales, lo que implica menor dolor posoperatorio, recuperación más rápida y mejores resultados cosméticos. La vía vaginal es segura, con mínimo riesgo de complicaciones y con mejores resultados posquirúrgicos comparada con el resto de las opciones de cirugía laparoscópica.


Abstract BACKGROUND The extraction of the myoma after laparoscopic resection can be done by: direct extraction, standard intra-abdominal morcellation, electric morcellation, extraction by posterior colpotomy or by minilaparotomy. Most of these options generally require placement of a 10-12 mm trocar and / or enlargement of the skin incision and fascia for tissue removal; In addition to the aesthetic disadvantages, it represents clinical implications such as the risk of incisional hernias. CLINICAL CASES We present 3 cases of patients with diagnosis of myomatosis of large elements, the smallest being 7 cm and the largest being 15 cm, in greater diameter, after the laparoscopic myomectomy the extraction of the complete surgical piece is performed through posterior colpotomy, presenting a favorable postoperative recovery, without associated symptoms. CONCLUSIONS The transvaginal extraction through posterior colpotomy represents a safe and effective alternative for the extraction of surgical pieces, the elasticity of the vagina allows the safe extraction of large pieces, avoiding the use of the morcellator and its possible risks; It also avoids expanding the abdominal incisions, associating to less postoperative pain, faster recovery and better cosmetic results. The vaginal route is a safe option with minimal risk of complications, and with better postsurgical results compared to the other options in laparoscopic surgery.

10.
Ginecol. obstet. Méx ; 86(6): 357-367, feb. 2018. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-984445

RESUMO

Resumen OBJETIVO Exponer el tratamiento médico y quirúrgico indicado en el Hospital Universitario de Saltillo a pacientes con acretismo placentario. MATERIALES Y MÉTODOS Estudio retrospectivo, transversal y analítico efectuado en pacientes tratadas con enfoque predictivo y preventivo de hemorragia obstétrica atendidas entre los años 2015-2017. Se incluyeron todas las pacientes operadas con la técnica descrita. Se analizan las variables maternas y fetales posquirúrgicas que aportan información para evaluar los resultados obstétricos mediante medias y porcentajes. RESULTADOS Se incluyeron 10 pacientes con media de edad de 31 años, 70% con antecedente de cesárea y 50% de legrado. El sangrado transquirúrgico tuvo una media de 1067 cc, con un tiempo quirúrgico promedio de 3.6 h, la media de transfusión de concentrados eritrocitarios fue de 2.3, el Apgar de los recién nacidos se reportó en ≥ 7, no se requirió reinternvención y no se encontraron casos de muerte materna. CONCLUSIONES Si bien el tamaño de la muestra es pequeño continuaremos recabando datos de lo sucedido con otras pacientes. Es indispensable estudiar más casos para tener evidencias de nuestra propuesta de tratamiento con pruebas aún más sólidas. También hace falta un seguimiento prolongado a las pacientes para conocer si hay o no complicaciones tardías.


Abstract OBJECTIVE Expose the medical and surgical treatment indicated in the University Hospital of Saltillo to patients with placental accreta. MATERIAL AND METHODS A retrospective, cross-sectional and analytical study, patients treated with a predictive and preventive approach of obstetric hemorrhage were studied in Hospital Universitario de Saltillo during 2015-2017. RESULTS 10 patients were included, with a mean age of 31 years, 70% had a history of cesarean section and 50% curettage. Transurgical bleeding averaged 1067 cc, an average surgical time of 3.6 hrs, average of transfusion of erythrocyte concentrates was 2.3, Apgar of newborns was reported ≥7, no surgical reoperation was required, no cases were found of maternal death. CONCLUSIONS Although the size of the sample is small, we will continue to collect data on what happened with other patients. It is essential to study more cases to have evidence of our treatment proposal with even more solid evidence. There is also a need for prolonged follow-up of patients to determine whether there are late complications or not.

11.
Angew Chem Int Ed Engl ; 56(3): 782-785, 2017 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-27933691

RESUMO

A new electrochemical framework for tracking individual soft particles in solution and monitoring their fusion with polarized liquid-liquid interfaces is reported. The physicochemical principle lies in the interfacial transfer of an ionic probe confined in the particles dispersed in solution and that is released upon their collision and fusion with the fluid interface. As a proof-of-concept, spike-like transients of a stochastic nature are reported in the current-time response of 1,2-dichloroethane(DCE)|water(W) submilli-interfaces after injection of DCE-in-W emulsions. The sign and potential dependence of the spikes reflect the charge and lipophilicity of the ionic load of the droplets. A comparison with dynamic light scattering measurements indicates that each spike is associated with the collision of a single sub-picoliter droplet. This opens a new framework for the study of single fusion events at the micro- and nanoscale and of ion transport across biomimetic soft interfaces.

12.
Biochemistry ; 55(45): 6209-6220, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27791355

RESUMO

The assembly of the protein complex of cytochrome c oxidase (COX), which participates in the mitochondrial respiratory chain, requires a large number of accessory proteins (the so-called assembly factors). Human COX assembly factor 3 (hCOA3), also known as MITRAC12 or coiled-coil domain-containing protein 56 (CCDC56), interacts with the first subunit protein of COX to form its catalytic core and promotes its assemblage with the other units. Therefore, hCOA3 is involved in COX biogenesis in humans and can be exploited as a drug target in patients with mitochondrial dysfunctions. However, to be considered a molecular target, its structure and conformational stability must first be elucidated. We have embarked on the description of such features by using spectroscopic and hydrodynamic techniques, in aqueous solution and in the presence of detergents, together with computational methods. Our results show that hCOA3 is an oligomeric protein, forming aggregates of different molecular masses in aqueous solution. Moreover, on the basis of fluorescence and circular dichroism results, the protein has (i) its unique tryptophan partially shielded from solvent and (ii) a relatively high percentage of secondary structure. However, this structure is highly flexible and does not involve hydrogen bonding. Experiments in the presence of detergents suggest a slightly higher content of nonrigid helical structure. Theoretical results, based on studies of the primary structure of the protein, further support the idea that hCOA3 is a disordered protein. We suggest that the flexibility of hCOA3 is crucial for its interaction with other proteins to favor mitochondrial protein translocation and assembly of proteins involved in the respiratory chain.


Assuntos
Proteínas de Membrana/química , Proteínas Mitocondriais/química , Multimerização Proteica , Estrutura Secundária de Proteína , Soluções/química , Sequência de Aminoácidos , Dicroísmo Circular , Simulação por Computador , Complexo IV da Cadeia de Transporte de Elétrons/química , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Cinética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Modelos Moleculares , Agregados Proteicos , Ligação Proteica , Domínios Proteicos , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Dodecilsulfato de Sódio/química
13.
ACS Nano ; 10(8): 7418-27, 2016 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-27459174

RESUMO

Current developments in nanotechnology have increased the demand for nanocrystal assemblies with well-defined shapes and tunable sizes. DNA is a particularly well-suited building block in nanoscale assemblies because of its scalable sizes, conformational variability, and convenient self-assembly capabilities via base pairing. In hybrid materials, gold nanoparticles (AuNPs) can be assembled into nanoparticle structures with programmable interparticle distances by applying appropriate DNA sequences. However, the development of stoichiometrically defined DNA/NP structures is still challenging since product mixtures are frequently obtained and their purification and characterization is the rate-limiting step in the development of DNA-NP hybrid assemblies. Improvements in nanostructure fractionation and characterization techniques offer great potential for nanotechnology applications in general. This study reports the application of analytical ultracentrifugation (AUC) for the characterization of anisotropic DNA-linked metal-crystal assemblies. On the basis of transmission electron microscopy data and the DNA primary sequence, hydrodynamic bead models are set up for the interpretation of the measured frictional ratios and sedimentation coefficients. We demonstrate that the presence of single DNA strands on particle surfaces as well as the shape factors of multiparticle structures in mixtures can be quantitatively described by AUC. This study will significantly broaden the possibilities to analyze mixtures of shape-anisotropic nanoparticle assemblies. By establishing insights into the analysis of nanostructure mixtures based on fundamental principles of sedimentation, a wide range of potential applications in basic research and industry become accessible.


Assuntos
DNA/química , Nanopartículas Metálicas , Nanotecnologia , Ouro , Ultracentrifugação
14.
J Biol Chem ; 290(38): 23077-93, 2015 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-26251518

RESUMO

Lysine acetylation is an important post-translational modification in the metabolic regulation of both prokaryotes and eukaryotes. In Escherichia coli, PatZ (formerly YfiQ) is the only known acetyltransferase protein and is responsible for acetyl-CoA synthetase acetylation. In this study, we demonstrated PatZ-positive cooperativity in response to acetyl-CoA and the regulation of acetyl-CoA synthetase activity by the acetylation level. Furthermore, functional analysis of an E809A mutant showed that the conserved glutamate residue is not relevant for the PatZ catalytic mechanism. Biophysical studies demonstrated that PatZ is a stable tetramer in solution and is transformed to its octameric form by autoacetylation. Moreover, this modification is reversed by the sirtuin CobB. Finally, an in silico PatZ tetramerization model based on hydrophobic and electrostatic interactions is proposed and validated by three-dimensional hydrodynamic analysis. These data reveal, for the first time, the structural regulation of an acetyltransferase by autoacetylation in a prokaryotic organism.


Assuntos
Acetiltransferases/química , Proteínas de Escherichia coli/química , Escherichia coli/enzimologia , Modelos Moleculares , Multimerização Proteica , Acetilação , Acetiltransferases/genética , Acetiltransferases/metabolismo , Substituição de Aminoácidos , Animais , Coenzima A Ligases/química , Coenzima A Ligases/genética , Coenzima A Ligases/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Humanos , Camundongos , Mutação de Sentido Incorreto , Estrutura Quaternária de Proteína , Sirtuínas/química , Sirtuínas/genética , Sirtuínas/metabolismo
15.
Ginecol Obstet Mex ; 83(5): 316-9, 2015 May.
Artigo em Espanhol | MEDLINE | ID: mdl-26233978

RESUMO

Obstetric hemorrhage remains the leading cause of maternal death, we continue to insist on preventive management of patients at high risk of massive pelvic bleeding, uterine dearterialization selective, significantly reduces the morbidity and mortality of the patient, on this ocassion we report the case of a 33-year-old with a diagnosis of cervical ectopic pregnancy of 13 gestational weeks, treated with selective dearterialization of hypogastric arteries with excellent results, without postoperative complications.


Assuntos
Histerectomia/métodos , Gravidez Ectópica/cirurgia , Hemorragia Uterina/cirurgia , Adulto , Colo do Útero , Feminino , Idade Gestacional , Humanos , Pelve , Gravidez , Hemorragia Uterina/etiologia
16.
Ginecol Obstet Mex ; 83(1): 32-40, 2015 Jan.
Artigo em Espanhol | MEDLINE | ID: mdl-26016314

RESUMO

BACKGROUND: Pelvic hemorrhage is a potential complication that occurs performing an obstetric or gynecological surgery, it is essential to know the distribution of pelvic vascular supplement, and implement preventive measures, can significantly reduce morbidity and mortality. OBJECTIVE: To describe the experience of hypogastric artery ligation, as a preventive and therapeutic measure of pelvic hemorrhage, this will give us new prospective lines for future investigation. METHODS: Retrospective observational study, in which all patient who were performed a surgical procedure and report hypogastric artery ligation at the Saltillo University Hospital, from January 2008 to July 2014 was studied. RESULTS: 41 patients were obtained with hypogastric artery ligation, 28 gynecological and 13 obstetric patients. Among gynecological indications, cancer surgery represents 67.85%, benign lesions 25% and pelvic abscess 7.12%. Obstetric indications were uterine hypotonia with 46%, placenta previa with 23.07% and uterine fibroids, broad ligament hematoma and abruptio placenta a total of 30.7%. There was one complication in relation with technique that was a laceration of internal iliac artery without any consequence linked to this. And uterine preserving of 62% was observed in obstetric patients. CONCLUSIONS: This technique is a feasible and safe for preventive and therapeutic management of pelvic surgery, with a low incidence of complications 3.5% in gynecological patients and 0% in obstetric, with a mortality of 0%.


Assuntos
Hemorragia Gastrointestinal/cirurgia , Complicações Pós-Operatórias/epidemiologia , Hemorragia Pós-Parto/cirurgia , Adulto , Idoso , Artérias/cirurgia , Feminino , Hemorragia Gastrointestinal/etiologia , Hospitais Universitários , Humanos , Ligadura , México , Pessoa de Meia-Idade , Hemorragia Pós-Parto/etiologia , Gravidez , Estudos Retrospectivos , Adulto Jovem
17.
Ginecol Obstet Mex ; 83(2): 110-5, 2015 Feb.
Artigo em Espanhol | MEDLINE | ID: mdl-25993774

RESUMO

Anterior pelvic exenteration is the last opportunity to control disease in a patient with cervical cancer in an advanced stage with a vesico-vaginal fistula, or in a patient with persistence of the disease and the need of improving the quality of life. In this case we present the cause of a 62 year old patient, with IVa stage cervical cancer, with bladder spread and a vesico-vaginal fistula treated with an anterior pelvic exenteration with Bricker technique and adjuvant treatment with radiotherapy.


Assuntos
Exenteração Pélvica/métodos , Neoplasias do Colo do Útero/cirurgia , Fístula Vesicovaginal/cirurgia , Feminino , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Qualidade de Vida , Radioterapia Adjuvante , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/radioterapia , Fístula Vesicovaginal/patologia , Fístula Vesicovaginal/radioterapia
18.
Carbohydr Polym ; 102: 223-30, 2014 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-24507276

RESUMO

SEC measurements of the [η]-M relationship for alginate from Macrocystis pyrifera and the wormlike model can be used to characterize flexibility through two independent treatments (Bohdanecky's equations and HYDFIT program), both providing the same results. Two different assumptions concerning mass per unit of length lead to different conclusions. First: persistence length decreases with ionic strength (the intrinsic component of the persistence length is 11.3 nm and the electrostatic component is 6 nm when ionic strength is 0.01). Second: persistence length is independent of ionic strength (12 nm). Either of these options shows that the wormlike model in itself is not sufficient to explain flexibility over the whole range of chain lengths for these polyelectrolytes. A plausible explanation could be the presence of a combination of short-range and long-range screening effects of the ions of the solutions. This would also explain some data found in the literature regarding alginate flexibility.

19.
Ginecol Obstet Mex ; 82(12): 791-5, 2014 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-25826963

RESUMO

OBJECTIVE: Search Histologic Chorioamnionitis frequency in patients in week 28 (+/-) and pregnancy with premature rupture of membranes. PATIENTS AND METHOD: Retrospective and observational study in which we studied all patients who came between June 28, 2011 and November 15, 2011 to receive obstetric care in the service of Tocochirurgical of the University Hospital of Saltillo, with greater than or equal 28 weeks of pregnancy. RESULTS: 598 patients were studied, and the frequency of premature rupture of membranes with histologic chorioamnionitis at term patients was, respectively, 1.7 and 5.3% in preterm labor. In the total sample frequency of histologic chorioamnionitis was 0.6% (4 patients) and, of these, 25% were term and 75% with preterm rupture. In patients with premature rupture of membranes the clinical chorioamnionitis was 0% valued by the criteria of Gibbs. CONCLUSIONS: The premature rupture of membranes is a risk factor important for histological chorioamnionitis. To decrease risk factors and possible complications, an established protocol must be taken.


Assuntos
Corioamnionite/epidemiologia , Corioamnionite/patologia , Feminino , Ruptura Prematura de Membranas Fetais , Humanos , Gravidez , Prevalência , Estudos Retrospectivos , Adulto Jovem
20.
Biophys Rev ; 5(2): 195-206, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23646070

RESUMO

The last three decades has seen some important advances in our ability to represent the conformation of proteins in solution on the basis of hydrodynamic measurements. Advances in theoretical modeling capabilities have been matched by commensurate advances in the precision of hydrodynamic measurements. We consider the advances in whole-body (simple ellipsoid-based) modeling-still useful for providing an overall idea of molecular shape, particularly for those systems where only a limited amount of data is available-and outline the ELLIPS suite of algorithms which facilitates the use of this approach. We then focus on bead modeling strategies, particularly the surface or shell-bead approaches and the HYDRO suite of algorithms. We demonstrate how these are providing great insights into complex issues such as the conformation of immunoglobulins and other multi-domain complexes.

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