RESUMEN
More than twenty genes are required for the correct initiation, spacing, and morphogenesis of trichomes in Arabidopsis. The initial selection of trichome precursors requires the activity of both the GLABROUS1 (GL1) and TRANSPARENT TESTA GLABROUS (TTG) genes. The GLABRA2 (GL2) gene is required for subsequent phases of trichome morphogenesis such as cell expansion, branching, and maturation of the trichome cell wall. Previous studies have shown that GL2 is a member of the homeodomain class of transcription factors. Here we report a detailed analysis of GL2 expression in the shoot using anti-GL2 antibodies and the GUS reporter gene fused to the GL2 promoter. The GL2 expression profile in the shoot is complex, and involves spatial and temporal variation in developing leaves and trichomes. Two separate promoter domains that are expressed in trichomes were identified. GL2, like GL1, is expressed in developing trichomes and in cells surrounding trichomes during early stages of trichome development. Unlike GL1, GL2 expression persists in mature trichomes. It was found that while GL1 and TTG were not required for the initiation of GL2 expression in the non-trichome cells, the presence of a functional GL1 or TTG gene was able to increase GL2 expression in these cells compared to ttg gl1 plants. The hypothesis that GL1 regulates aspects of GL2 expression is consistent with epistatic analysis of gl1 and gl2 and the expression patterns of GL1 and GL2. In support of this hypothesis, it was found that ectopic expression of GL1 in the presence of ectopic expression of the maize R gene, which can bypass the requirement for TTG, can ectopically activate GL2 transcription.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis/genética , Regulación del Desarrollo de la Expresión Génica/genética , Proteínas de Homeodominio/genética , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/genética , Arabidopsis/crecimiento & desarrollo , Regulación de la Expresión Génica de las Plantas/genética , Genes de Plantas/genética , Genes Reporteros/genética , Histocitoquímica , Inmunohistoquímica , Microscopía Electrónica , Morfogénesis/fisiología , Mutagénesis/genética , Proteínas Nucleares/genética , Hojas de la Planta/ultraestructura , Regiones Promotoras Genéticas/genética , Eliminación de Secuencia/genética , Factores de Transcripción/metabolismoRESUMEN
The combination of two factors gives early HIV infection an especially strong influence on transmission dynamics: (a) increased transmission probabilities and (b) increased transmission potential of partners infected during this period. Most attention has been focused on the first factor because it fits the way we usually think about risk factors affecting individuals. The second factor acts not on individuals, but across chains of transmission. It is missed by models with constant partnership formation rates over an individual's life or with random mixing. It cannot be assessed from available data collected from individuals. Its assessment requires data from both individuals in a partnership. We demonstrate that this second effect can be so strong that early infection can dominate transmission dynamics even when transmission probabilities are only modestly increased. This second effect is not directly parameterized in our models but arises from two realistic types of temporal variation in partnership formation: (a) Partnership formation rates vary by age with preferential partnership formation in one's own age group, and (b) individuals of any age can experience transient periods of high-risk partnership formation. In a model with only the age-related effect, early infection is observed to dominate transmission dynamics when 20% of transmissible virus is allocated to the first 6 weeks of infection, 7% to middle infection, and 73% to late infection. This domination occurs both early in the course of an epidemic and later when endemic infection levels have been reached. When the second effect is added, early infection is seen to dominate transmission in a model allocating 10% of transmissible virus to the first 6 months, 40% to middle infection, and 50% to late infection. In this model, transmission probabilities during early infection are only 4.17 times those of middle infection and half those of late-stage infection.
Asunto(s)
Simulación por Computador , Infecciones por VIH/transmisión , Modelos Biológicos , Factores de Edad , Humanos , Probabilidad , Factores de RiesgoRESUMEN
There is little information available on the effects of periodontal therapy on tissue levels of interleukin-6 (IL-6). This study compares IL-6 concentrations in gingiva and gingival crevicular fluid (GCF) from patients requiring surgical procedures following Phase I periodontal therapy. Sites requiring surgery due to "unresolved" intrabony pockets were compared to sites not requiring surgery ("resolved") in each patient. Resolved sites had minimal histologic evidence of chronic inflammation and IL-6 accumulation; unresolved sites contained a substantial number of chronic inflammatory cells and IL-6 was widely distributed. IL-6 levels in GCF were significantly greater at resolved than at unresolved gingival sites (P < 0.001); however, IL-6 tissue levels were significantly greater at unresolved than in resolved gingival sites (P < 0.01). These results suggest that IL-6 levels were elevated in gingival connective tissue adjacent to intrabony pockets which had not been resolved following Phase I therapy. Thus, intrabony pocket resolution may be affected by accumulation of IL-6 in the adjacent gingival connective tissue, which may result from increased rates of synthesis or reduced rates of release from gingiva into the GCF.
Asunto(s)
Encía/química , Interleucina-6/análisis , Enfermedades Periodontales/terapia , Adulto , Anciano , Pérdida de Hueso Alveolar/metabolismo , Pérdida de Hueso Alveolar/patología , Pérdida de Hueso Alveolar/cirugía , Pérdida de Hueso Alveolar/terapia , Tejido Conectivo/química , Tejido Conectivo/patología , Epitelio/química , Epitelio/patología , Femenino , Encía/patología , Líquido del Surco Gingival/química , Hemorragia Gingival/metabolismo , Hemorragia Gingival/patología , Hemorragia Gingival/terapia , Humanos , Masculino , Persona de Mediana Edad , Pérdida de la Inserción Periodontal/metabolismo , Pérdida de la Inserción Periodontal/patología , Pérdida de la Inserción Periodontal/cirugía , Pérdida de la Inserción Periodontal/terapia , Enfermedades Periodontales/metabolismo , Enfermedades Periodontales/patología , Enfermedades Periodontales/cirugía , Bolsa Periodontal/metabolismo , Bolsa Periodontal/patología , Bolsa Periodontal/cirugía , Bolsa Periodontal/terapia , Periodontitis/metabolismo , Periodontitis/patología , Periodontitis/cirugía , Periodontitis/terapiaRESUMEN
A methodology is presented with examples of the productivity, the staffing required, the resultant productivity, and costs that can be obtained for hospital units that are subject to random work demands such as laboratory, radiology, physical therapy, and nuclear medicine. The methodology assumes that the hospital has a labor productivity system that produces the RVUs or earned hours of work accomplished daily by shift. Factors considered are the distribution of the capabilities of the work force, the fatigue and delay allowances of the work standards, the quality of the work standards, the maximum amount of overtime that people will be asked to work, staffing policies such as constant or different staffing levels for each day of the week, and worker selection processes. Predicted results are compared with present practice, which indicates that substantial cost reductions can occur with the use of the methodology.
Asunto(s)
Eficiencia , Departamentos de Hospitales , Modelos Teóricos , Administración de Personal , Admisión y Programación de Personal , Presupuestos , Costos y Análisis de Costo , Estudios de Tiempo y Movimiento , Recursos HumanosRESUMEN
The authors use a truncated sequential probability ratio test (SPRT) to diagnose diabetes. It is hypothesized that, for a given oral glucose tolerance test (OGTT), the differences between successive observations are more diagnostic than the observations alone. Using such differences in a SPRT, OGTT test data for 950 subjects are analyzed and thresholds for classifying diabetes and normal values are established. This sequential approach provides the same diagnosticity as that obtained by using the National Diabetic Data Group criteria, but it is more efficient. In particular, the procedure significantly reduces the sampling cost and average patient waiting time.