RESUMEN
UNLABELLED: We examined the rate of clinical vertebral fractures, and the circumstances associated with the fractures, in a cohort of 5,995 US older men. Fractures were more common in the most elderly men, and were usually associated with falls and other low-energy trauma. INTRODUCTION: Little is known about clinical vertebral fractures in older men. We postulated that clinical vertebral fractures occur with falls, affect men with osteoporosis, and are more common as age increases. METHODS: Five thousand nine hundred and ninety-five men aged > or =65 years were followed prospectively for an average of 4.7 years. Men with incident clinical vertebral fractures were compared to controls. RESULTS: One percent (n = 61) sustained incident clinical vertebral fractures (2.2/1,000 person-years). The rate of fracture rose with age (0.7% in men 65-69 years and 5% > or =85 years). Fractured men were more likely frail (8.2% vs. 2.2%), more often fell (36.1% vs. 21%) and had lower total hip and lumbar spine BMD (all p values < or =0.002). In 73.8% of cases fractures were precipitated by no known trauma or by low-energy trauma, including falls in 57.3% Fractures were thoracic in 33% and lumbar in 56%. Men with an incident vertebral fracture were more likely to be osteoporotic (13% vs. 2%, p < 0.0001), but most men with incident fractures did not have osteoporosis. CONCLUSIONS: Incident clinical vertebral fractures were relatively common in older men and the rate increased after age 80 years. Fractures were usually associated with minimal trauma, most commonly a fall.
Asunto(s)
Densidad Ósea/fisiología , Osteoporosis/epidemiología , Fracturas de la Columna Vertebral/epidemiología , Factores de Edad , Anciano , Anciano de 80 o más Años , Huesos/fisiología , Estudios de Seguimiento , Humanos , Masculino , Modelos de Riesgos Proporcionales , Factores de Riesgo , Fracturas de la Columna Vertebral/etiología , Estados Unidos/epidemiologíaRESUMEN
Gene therapy and DNA vaccination applications have increased the demand for highly purified plasmid DNA (pDNA) in the last years. One of the main problems related to the scale-up of pDNA purification is the degradation of the supercoiled (sc) isoforms during cell culture and multi-stage purification. In this work, a systematic study of the stability of two model plasmids (3,697 and 6,050 bp) during a mid-scale production process, which includes fermentation, alkaline lysis, isopropanol and ammonium sulphate precipitation and hydrophobic interaction chromatography, was performed. Results indicate that by extending cell culture (up to 26 h) and cell lysis (up to 2 h) it is possible to significantly reduce the amounts of RNA, without significantly compromising the yields of the sc pDNA isoform, a feature that could be conveniently exploited for downstream processing purposes. The stability of pDNA upon storage of E. coli pellets at different temperatures indicates that, differently from RNA, pDNA is remarkably stable when stored in cell pellets (>3 weeks at 4 degrees C, >12 weeks at -20 degrees C) prior to processing. With alkaline lysates, however, storage at -20 degrees C is mandatory to avoid sc pDNA degradation within the first 8 weeks. Furthermore, the subsequent purification steps could be carried out at room temperature without significant pDNA degradation. Since the unit operations and process conditions studied in this work are similar to those generally used for plasmid DNA production, the results presented here may contribute to improve the current knowledge on plasmid stability and process optimization.
Asunto(s)
Técnicas de Cultivo de Célula/métodos , ADN Superhelicoidal/química , Escherichia coli/crecimiento & desarrollo , Vectores Genéticos/química , Plásmidos/química , 2-Propanol/química , Álcalis/química , ADN Superhelicoidal/aislamiento & purificación , Escherichia coli/química , Escherichia coli/genética , Vectores Genéticos/aislamiento & purificación , Plásmidos/aislamiento & purificación , Sales (Química)/químicaRESUMEN
Statistical modeling of links between genetic profiles with environmental and clinical data to aid in medical diagnosis is a challenge. Here, we present a computational approach for rapidly selecting important clinical data to assist in medical decisions based on personalized genetic profiles. What could take hours or days of computing is available on-the-fly, making this strategy feasible to implement as a routine without demanding great computing power. The key to rapidly obtaining an optimal/nearly optimal mathematical function that can evaluate the "disease stage" by combining information of genetic profiles with personal clinical data is done by querying a precomputed solution database. The database is previously generated by a new hybrid feature selection method that makes use of support vector machines, recursive feature elimination and random sub-space search. Here, to evaluate the method, data from polymorphisms in the renin-angiotensin-aldosterone system genes together with clinical data were obtained from patients with hypertension and control subjects. The disease "risk" was determined by classifying the patients' data with a support vector machine model based on the optimized feature; then measuring the Euclidean distance to the hyperplane decision function. Our results showed the association of renin-angiotensin-aldosterone system gene haplotypes with hypertension. The association of polymorphism patterns with different ethnic groups was also tracked by the feature selection process. A demonstration of this method is also available online on the project's web site.
Asunto(s)
Diagnóstico por Computador/métodos , Predisposición Genética a la Enfermedad , Hipertensión/diagnóstico , Reconocimiento de Normas Patrones Automatizadas , Polimorfismo Genético/genética , Sistema Renina-Angiotensina/genética , Algoritmos , Estudios de Casos y Controles , Femenino , Genotipo , Humanos , Hipertensión/genética , Masculino , Modelos Genéticos , Reproducibilidad de los ResultadosRESUMEN
Large-scale processes used to manufacture grams of plasmid DNA (pDNA) should be cGMP compliant, economically feasible, and environmentally friendly. Alcohol and salt precipitation techniques are frequently used in plasmid DNA (pDNA) downstream processing, as concentration and prepurification steps, respectively. This work describes a study of a standard 2-propanol (IsopOH; 0.7 v/v) and ammonium sulfate (AS; 2.5 M) precipitation. When inserted in a full process, this tandem precipitation scheme represents a high economic and environmental impact due to the large amounts of the two precipitant agents and their environmental relevance. Thus, major goals of the study were the minimization of precipitants and the selection of the best operating conditions for high pDNA recovery and purity. The pDNA concentration in the starting Escherichia coli alkaline lysate strongly affected the efficiency of IsopOH precipitation as a concentration step. The results showed that although an IsopOH concentration of at least 0.6 (v/v) was required to maximize recovery when using lysates with less than 80 microg pDNA/mL, concentrations as low as 0.4 v/v could be used with more concentrated lysates (170 microg pDNA/mL). Following resuspension of pDNA pellets generated by 0.6 v/v IsopOH, precipitation at 4 degrees C with 2.4 M AS consistently resulted in recoveries higher than 80% and in removal of more than 90% of the impurities (essentially RNA). An experimental design further indicated that AS concentrations could be reduced down to 2.0 M, resulting in an acceptable purity (21-23%) without compromising recovery (84-86%). Plasmid recovery and purity after the sequential IsopOH/AS precipitation could be further improved by increasing the concentration factor (CF) upon IsopOH precipitation from 2 up to 25. Under these conditions, IsopOH and AS concentrations of 0.60 v/v and 1.6 M resulted in high recovery (approximately 100%) and purity (32%). In conclusion, it is possible to reduce substantially the mass of precipitation agents used without affecting recovery, if a small concession is made regarding purity. This directly translates into an improvement of the process economics and in a reduction of the environmental impact of the process.
Asunto(s)
2-Propanol/química , Sulfato de Amonio/química , ADN/aislamiento & purificación , Plásmidos/aislamiento & purificación , Precipitación Química , Cromatografía Líquida de Alta Presión , Precipitación Fraccionada , Interacciones Hidrofóbicas e Hidrofílicas , Plásmidos/químicaRESUMEN
Statistical modeling of links between genetic profiles with environmental and clinical data to aid in medical diagnosis is a challenge. Here, we present a computational approach for rapidly selecting important clinical data to assist in medical decisions based on personalized genetic profiles. What could take hours or days of computing is available on-the-fly, making this strategy feasible to implement as a routine without demanding great computing power. The key to rapidly obtaining an optimal/nearly optimal mathematical function that can evaluate the [quot ]disease stage[quot ] by combining information of genetic profiles with personal clinical data is done by querying a precomputed solution database. The database is previously generated by a new hybrid feature selection method that makes use of support vector machines, recursive feature elimination and random sub-space search. Here, to evaluate the method, data from polymorphisms in the renin-angiotensin-aldosterone system genes together with clinical data were obtained from patients with hypertension and control subjects. The disease [quot ]risk[quot ] was determined by classifying the patients' data with a support vector machine model based on the optimized feature; then measuring the Euclidean distance to the hyperplane decision function. Our results showed the association of renin-angiotensin-aldosterone system gene haplotypes with hypertension. The association of polymorphism patterns with different ethnic groups was also tracked by the feature selection process. A demonstration of this method is also available online on the project's web site.
Asunto(s)
Femenino , Humanos , Masculino , Diagnóstico por Computador/métodos , Predisposición Genética a la Enfermedad , Hipertensión/diagnóstico , Reconocimiento de Normas Patrones Automatizadas , Polimorfismo Genético/genética , Sistema Renina-Angiotensina/genética , Algoritmos , Estudios de Casos y Controles , Genotipo , Hipertensión/genética , Modelos Genéticos , Reproducibilidad de los ResultadosRESUMEN
Recognition of antigens by immunocompetent cells involves interactions that are specific to the chemical sequence and conformation of the epitope (antigenic determinant). Adjuvants that are currently used to enhance immunity to antigens tend to either alter the antigen conformation through surface adsorption or shield potentially critical determinants, e.g., functional groups. It is demonstrated here that surface-modified diamond nanoparticles (5-300 nm) provide conformational stabilization, as well as a high degree of surface exposure to protein antigens. By enhancing the availability and activity of the antigen in vivo, a strong, specific immune response can be elicited. Results are demonstrated for mussel adhesive protein (MAP), a substance for which conventional adjuvants have proven only marginally successful in evoking an immune response. Surface-modified diamond nanoparticles as antigen delivery vehicles are a novel example of the exciting marriage of materials science, chemistry, and biology.