Identificación de áreas prioritarias para la conservación de razas de maíz en la sierra de Ecuador

En Ecuador el maíz es el cultivo más importante en superficie y es base de la alimentación para la población rural que vive en los Andes. A diferencia de lo que sucede en la Costa, en la región Sierra todavía se cultivan numerosas variedades tradicionales que se agrupan en veinticuatro razas. Mantener esta diversidad es, pues, de gran importancia no solo para la seguridad alimentaria, sino también como fuente de genes para tolerancia a factores abióticos que podrían ser incorporados a las variedades modernas. Si bien parte de esta diversidad fue recolectada a mediados del siglo pasado y está siendo conservada en distintos bancos de germoplasma, es deseable que su conservación in situ también esté asegurada, entre otras razones, porque de esta manera el cultivo puede seguir evolucionando. Para poder implementar un plan de conservación en finca que contribuya a preservar este patrimonio, resulta imprescindible identificar áreas idóneas donde concentrar los recursos y conocer las características y tipologías de los agricultores que manejan la diversidad actual. Generar esta información es el objetivo principal de esta investigación y para lograrlo se han llevado a cabo cuatro estudios: (1) Análisis de la diversidad a nivel de razas e identificación de áreas de alta riqueza de razas, alta diversidad morfológica y/o alta diversidad ecogeográfica en la Sierra de Ecuador, (2) Identificación del perfil y las características de los agricultores que conservan y manejan las variedades tradicionales de maíz en la Sierra de Ecuador, (3) Análisis del conocimiento local, manejo y usos de variedades tradicionales de maíz en la Sierra de Ecuador, y (4) Identificación de áreas de alta diversidad y bajo riesgo de pérdida para la conservación en finca de maíz en la Sierra de Ecuador. Para el primer estudio se visitaron 303 fincas distribuidas a lo largo de la Sierra y se recolectaron 636 muestras que fueron caracterizadas morfológicamente mediante 14 variables: 8 relacionadas con la mazorca (forma, longitud y diámetro de la mazorca, color y diámetro de olote y número y disposición de hileras) y 7 referidas el grano (número total de granos, color, forma, longitud, anchura y grosor de grano y tipo de endospermo). Adicionalmente, las fincas donde se tomaron las muestras fueron caracterizadas ecogeográficamente mediante 5 variables climáticas (temperatura media estacional, rango de temperatura media anual, temperatura mínima de diciembre, precipitación estacional y precipitación de octubre), 2 geofísicas (altitud y pendiente) y 5 edáficas (textura principal del suelo, profundidad a roca, pH, contenido en materia orgánica y fertilidad). A partir de esta información y mediante técnicas de sistemas de información geográfica (SIG), se generaron mapas de distribución por raza en formato vectorial y un mapa de riqueza de razas, un mapa de diversidad morfológica y un mapa de diversidad ecogeográfica en formato ráster con celdas de 10 km x 10 km. Los resultados permitieron constatar que, en los últimos 60 años, no se ha perdido ninguna raza. Sin embargo, Canguil, Chaucho y Clavito han dejado de cultivarse en algunas provincias con la consiguiente erosión genética del cultivo. La caracterización morfológica detectó diferencias en el grado de variabilidad intra-raza, siendo Patillo Ecuatoriano, Racimo de Uva y Uchima las razas más heterogéneas tanto para los caracteres cualitativos como cuantitativos. A nivel climático y geofísico, también se detectaron diferencias en el grado de variación intra-raza; Cuzco Ecuatoriano, Kcello Ecuatoriano y Montaña Ecuatoriana fueron las razas que en promedio presentaron mayores rangos y coeficientes de variación para estas variables ecogeográficas. En cuanto a las condiciones edáficas todas las razas, excepto Cónico Dentado, presentaron una gran heterogeneidad, pudiendo crecer tanto en suelos ricos como pobres, con valores de pH entre ácido y moderadamente alcalino. La comparación entre razas reveló diferencias significativas en los rangos ambientales de algunas razas como Cónico Dentado, que tiende a cultivarse a menor altitud y, por tanto, en ambientes menos fríos y de mayor precipitación que Blanco Blandito, Patillo Ecuatoriano, Sabanero Ecuatoriano, Uchima y Zhima. Para la mayoría de las razas se encontraron materiales potencialmente adaptados a condiciones de estrés (precipitación estacional inferior a 500 mm y suelos con pH entre 4.5 y 5.5). Finalmente, los mapas de riqueza, de diversidad morfológica y de diversidad ecogeográfica mostraron 36 celdas de alta diversidad repartidas en las 10 provincias de la Sierra: 11 celdas en las provincias del norte, 11 en las provincias del centro y 14 en las provincias del sur. Para la caracterización e identificación de las tipologías de los agricultores que cultivan maíz en la Sierra de Ecuador y el análisis de los posibles factores de riesgo de pérdida de diversidad, se realizaron entrevistas individuales y semiestructuradas a los agricultores dueños de las fincas donde se recolectaron las muestras para el estudio de diversidad (254 en total). Las preguntas que se formularon (11 abiertas y 5 cerradas) estuvieron organizadas en seis bloques: datos del agricultor, características de la finca, diversidad y conocimiento del cultivo, manejo del cultivo, usos y flujo de semillas. Los resultados indicaron que la diversidad de maíz que hay en la Sierra de Ecuador es manejada mayoritariamente por agricultores mestizos, de entre 30 y 55 años, que cultivan una o dos variedades tradicionales para autoconsumo, en parcelas de menos de 0.5 ha y en asocio con fréjol. El análisis de segmentación mediante el algoritmo Chi-square automatic interaction detection (CHAID) permitió identificar un pequeño grupo de agricultores indígenas con parcelas medianas (entre 0.5 ha y 1.5 ha) que conservan un mayor número de variedades tradicionales por finca que el agricultor promedio. Los análisis estadísticos no detectaron diferencias significativas entre etnias (mestizo vs. indígena), géneros (hombre vs. mujer) y grupos de edad (jóvenes menores de 30 años, adultos entre 30 y 55 años y adultos mayores de 55 años) en lo que respecta al conocimiento del cultivo (criterios de reconocimiento y razones de preferencia) y manejo (tipo de cultivo), pero sí detectaron diferencias entre regiones, principalmente en el modo de cultivar el maíz; mientras que en el norte y sur tienden a sembrarlo en asocio y con un mayor número de especies, en el centro acostumbran a cultivarlo preferentemente solo. En cuanto a los usos, se recopilaron hasta 39 modos diferentes de consumir maíz, siendo Kcello Ecuatoriano y Zhima las razas para las que se registró un mayor número de usos. La comparación del número medio de usos por variedad entre etnias evidenció que los agricultores mestizos utilizan sus variedades tradicionales de forma más variada que los indígenas. Entre los factores de riesgo que se analizaron, el bajo porcentaje de jóvenes agricultores que se ocupan de las fincas podría suponer una amenaza a medio plazo por falta de relevo generacional. Adicionalmente, las numerosas sinonimias y homonimias que se detectaron y el bajo intercambio de semillas también podrían ser causa de pérdida de diversidad, bien por reemplazo o por envejecimiento de la semilla. Finalmente, se concluyó que las razas Chaucho, Complejo Chillo-Huandango, Complejo Mishca-Huandango, Cónico Dentado, Montaña Ecuatoriana y Sabanero Ecuatoriano son particularmente vulnerables, no solo por su baja presencia, sino también por el color de grano que tienen (los mismos que la mayoría de las razas más comunes) y carecer de nombres y usos específicos. Finalmente, para la priorización de áreas de conservación en finca para maíz en la Sierra de Ecuador, se utilizaron 13 criterios de diferente naturaleza: 2 ecogeográficos (precipitación, diversidad ecogeográfica), 6 biológicos (grado de presencia del cultivo, riqueza de razas, diversidad morfológica, presencia de mezclas, presencia de razas locales y riesgo de erosión genética), 3 culturales (abundancia de variedades por finca, diversidad de usos y frecuencia de intercambio) y 2 demográficos (tamaño de la población y distancia a núcleos urbanos). Mediante técnicas SIG y de evaluación multicriterio, los valores originales de las capas-criterio fueron transformados a una escala de 0 a 100. Posteriormente, las capas-criterio normalizadas fueron sumadas utilizando tres métodos de ponderación: (1) mismo peso, (2) diferente peso según la puntuación otorgada por 72 expertos, y (3) diferente peso según el método de comparación entre pares de criterios. Los resultados permitieron identificar ocho celdas de 10 km x 10 km con alta puntuación (> 65): tres celdas en el norte (una en cada una de las provincias), una celda en el centro (en la provincia de Cotopaxi), y cuatro celdas en la región sur (dos en Azuay y otras dos en Loja). ABSTRACT In Ecuador, the maize is the most important cultivation in surface and it is a base of the feeding for the rural population who lives in the Andes. In contrast to what it happens on the Coast, in the Sierra region still there are cultivated numerous traditional varieties that are grouped into twenty-four races. Maintaining this diversity is, therefore, of great importance not only for food security, but also as a source of genes for tolerance to abiotic factors could be incorporated into modern varieties. Although part of this diversity was collected in the middle of the last century and is still preserved in various germplasm banks, it is desirable for the in situ conservation also is assured, among other reasons, because in this way the crop can continue to evolve. To be able to implement a conservation plan on farm that contribute to preserving this heritage, it is essential to identify suitable areas where to concentrate resources and know the characteristics and typology of farmer who managed the current diversity. To generate this information is the main target of this investigation and to achieve this, four studies have been carried out: (1) Analysis of the diversity at races and identification of areas of high richness of races, high morphological diversity and / or ecogeographical high diversity in the Sierra of Ecuador, (2) Identification of the profile and characteristics of farmers who conserve and manage traditional varieties of maize in the Sierra of Ecuador, (3) Analysis of local knowledge, management and use of traditional varieties of maize in the Sierra of Ecuador, and (4) Identification of areas of high diversity and low risk of loss for the conservation of maize in the Sierra of Ecuador. For the first study were visited 303 farms distributed along the Sierra and collected 636 samples that were characterized morphologically by 14 variables: 8 related to the ear (shape, length and diameter of the cob, colour, and diameter of cob and number and arrangement of rows) and 7 referred to the grain (total number of grain, colour, shape, length, width, and thickness and type of grain endosperm). In addition, the farms where the samples were taken were characterized ecogeographically through 5 climatic variables (seasonal average temperature, range of average annual temperature, minimum temperature for December, seasonal precipitation and precipitation of October), 2 geophysical (altitude and slope) and edaphic 5 (main texture of the soil, deep rock, pH, content of organic matter and fertility). From this information and techniques of geographic information systems (GIS), maps were generated for distribution by race in vector format and a map of richness of races, a map of morphological diversity and a map of ecogeographical diversity in raster format with cells of 10 km x 10 km. The results allowed observing that, over the past 60 years, it has not lost any race. Nevertheless, Canguil, Chaucho and Clavito have stopped being cultivated in some provinces with the consequent genetic erosion of the cultivation. The morphological characterization detected differences in the degree of variability intra-race, being Patillo Ecuatoriano, Racimo de Uva and Uchima races more heterogeneous both for the qualitative and quantitative characters. At climate and geophysical level, also detected differences in the degree of variation intra-race; Cuzco Ecuatoriano, Kcello Ecuatoriano and Montaña Ecuatoriana were races that, on average, showed higher ranges and coefficients of variation for these geographical characters. In terms of the edaphic conditions, all races, except Cónico Dentado, showed a great heterogeneity, and can grow both in rich and poor soils, with pH values between acid and moderately alkaline. The comparison between races revealed significant differences in the environmental ranges in some races as Cónico Dentado, which tends to be grown at lower elevations and, therefore, in environments less cold and greater precipitation than Blanco Blandito, Patillo Ecuatoriano, Sabanero Ecuatoriano, Uchima and Zhima. For most of the races were found materials potentially adapted to stress conditions (seasonal precipitation less than 500 mm and soil with a pH between 4.5 and 5.5). Finally, the maps of richness, morphologic diversity and ecogeographical diversity showed 36 cells high diversity distributed in 10 provinces of the Sierra: 11 cells in the northern provinces, 11 in the central provinces and 14 in the southern provinces. For the characterization and identification of the typology of the farmers who cultivate corn in the Sierra of Ecuador and the analysis of the possible factors of risk of loss of diversity, there were realized interviews individual and semistructured to the farmers’ owners of the farms where the samples were gathered for the study of diversity (254 in whole). The questions that were formulated (11 opened ones and 5 closed ones) were organized in six blocks: data of the farmer, characteristics of the farm, diversity and knowledge of the crop, crop management, uses and seed flow. The results indicated that the maize diversity that exist in the Sierra of Ecuador is managed mainly by mestizo farmers, aged between 30 and 55, who cultivate one or two traditional varieties for self-consumption, on plots of less than 0.5 has and in associated with beans. The segmentation analysis algorithm using the Chi-square automatic interaction detection (CHAID technique), allowed to identify a small group of indigenous farmers with medium-sized plots (between 0.5 there is and 1.5 it is) that a major number of traditional varieties preserves for farm that the average farmer. The statistical analysis did not detect significant differences between ethnic groups (mestizos vs. indigenous), genres (man vs. women) and age groups (young people under 30 years of age, adults between 30 and 55 years and adults over 55 years old) in regards to the knowledge of the cultivation (recognition criteria and reasons of preference) and management (type of crop), but if detected differences between regions, mainly on the mode of cultivating the maize; while in the north and south they tend to sow in associate and with a greater number of species, in the center accustomed to cultivate it preferably only. In regards to the uses, they were compiled up to 39 different ways of consuming maize, being Kcello Ecuatoriano and Zhima the races for which a major number of uses registered. The comparison of the average number of uses per variety between ethnic groups showed that the mestizo farmers used their traditional varieties of form more varied than the indigenous people. Between the factors of risk that were analyzed, the low percentage of young farmers who deal with the farms might suppose a medium-term threat for lack of generational relief. In addition, the numerous synonyms and homonyms that were detected and the low seed exchange could also be a cause of loss of diversity, either by replacement or by aging of the seed. Finally, it was concluded that the races Chaucho, Complex Chillo-Huandango, Complex Mishca-Huandango, Cónico Dentado, Montaña Ecuatoriana and Sabanero Ecuatoriano are particularly vulnerable, not only because of their low presence, but also by the grain color they have (the same as the majority of races more common) and lack of names and specific uses. Finally, for the prioritization of maize conservation areas on farm in the Sierra of Ecuador, used 13 criteria of different nature: 2 ecogeographic (precipitation, diversity ecogeographical), 6 biological (degree of presence of the crop, races richness, morphological diversity, the presence of mixtures, presence of local races and risk of genetic erosion), 3 cultural (abundance of varieties per farm, diversity of uses and frequency of exchange) and 2 demographic (population size and distance to urban centers). Using GIS techniques and multicriteria evaluation, the original values of the layers-criterion were transformed to a scale of 0 to 100. Later, the normalized layers - criteria were added using three weighting methods: (1) the same weight, (2) different weight according to the score given by 72 experts, and (3) different weight according to the method of comparison between pairs of criteria. The results allowed to identify eight 10 km cells x 10 km with high punctuation (> 65): three cells in the north (one in each of the provinces), a cell in the center (in the Cotopaxi province), and four cells in the south region (two in Azuay and other two in Loja).

Hypsographic demography: The distribution of human population by altitude

The global distribution of the human population by elevation is quantified here. As of 1994, an estimated 1.88 × 109 people, or 33.5% of the world’s population, lived within 100 vertical meters of sea level, but only 15.6% of all inhabited land lies below 100 m elevation. The median person lived at an elevation of 194 m above sea level. Numbers of people decreased faster than exponentially with increasing elevation. The integrated population density (IPD, the number of people divided by the land area) within 100 vertical meters of sea level was significantly larger than that of any other range of elevations and represented far more people. A significant percentage of the low-elevation population lived at moderate population densities rather than at the highest densities of central large cities. Assessments of coastal hazards that focus only on large cities may substantially underestimate the number of people who could be affected.

Screening for hypercholesterolaemia in primary care: randomised controlled trial of postal questionnaire appraising risk of coronary heart disease

Objectives: To validate a self administered postal questionnaire appraising risk of coronary heart disease. To determine whether use of this questionnaire increased the percentage of people at high risk of coronary heart disease and decreased the percentage of people at low risk who had their cholesterol concentration measured.

The sutureless aortic valve at 1 year: A large multicenter cohort study

OBJECTIVE Sutureless aortic valve replacement (AVR) offers an alternative to standard AVR in aortic stenosis. This prospective, single-arm study aimed to demonstrate safety and effectiveness of a bovine pericardial sutureless aortic valve at 1 year. METHODS From February 2010 to September 2013, 658 patients (mean age 78.3 ± 5.6 years; 40.0% octogenarian; 64.4% female; mean Society of Thoracic Surgeons score 7.2 ± 7.4) underwent sutureless AVR in 25 European centers. Concomitant cardiac procedures were performed in 29.5% and minimally invasive cardiac surgery in 33.3%. RESULTS One-year site-reported event rates were 8.1% for all-cause mortality, 4.5% for cardiac mortality, 3.0% for stroke, 1.9% for valve-related reoperation, 1.4% for endocarditis, and 0.6% for major paravalvular leak. No valve thrombosis, migration, or structural valve deterioration occurred. New York Heart Association class improved at least 1 level in 77.5% and remained stable (70.4% New York Heart Association class I or II at 1 year). Mean effective orifice area was 1.5 ± 0.4 cm(2); pressure gradient was 9.2 ± 5.0 mm Hg. Left ventricular mass decreased from 138.5 g/m(2) before surgery to 115.3 g/m(2) at 1 year (P < .001). Echocardiographic core laboratory findings confirmed that paravalvular leak was rare and remained stable during follow-up. CONCLUSIONS The Perceval sutureless valve resulted in low 1-year event rates in intermediate-risk patients undergoing AVR. New York Heart Association class improved in more than three-quarters of patients and remained stable. These data support the safety and efficacy to 1 year of the Perceval sutureless valve in this intermediate-risk population.

Prospective longitudinal voxel-based morphometry study of major depressive disorder in young individuals at high familial risk

BACKGROUND Previous neuroimaging studies indicate abnormalities in cortico-limbic circuitry in mood disorder. Here we employ prospective longitudinal voxel-based morphometry to examine the trajectory of these abnormalities during early stages of illness development. METHOD Unaffected individuals (16-25 years) at high and low familial risk of mood disorder underwent structural brain imaging on two occasions 2 years apart. Further clinical assessment was conducted 2 years after the second scan (time 3). Clinical outcome data at time 3 was used to categorize individuals: (i) healthy controls ('low risk', n = 48); (ii) high-risk individuals who remained well (HR well, n = 53); and (iii) high-risk individuals who developed a major depressive disorder (HR MDD, n = 30). Groups were compared using longitudinal voxel-based morphometry. We also examined whether progress to illness was associated with changes in other potential risk markers (personality traits, symptoms scores and baseline measures of childhood trauma), and whether any changes in brain structure could be indexed using these measures. RESULTS Significant decreases in right amygdala grey matter were found in HR MDD v. controls (p = 0.001) and v. HR well (p = 0.005). This structural change was not related to measures of childhood trauma, symptom severity or measures of sub-diagnostic anxiety, neuroticism or extraversion, although cross-sectionally these measures significantly differentiated the groups at baseline. CONCLUSIONS These longitudinal findings implicate structural amygdala changes in the neurobiology of mood disorder. They also provide a potential biomarker for risk stratification capturing additional information beyond clinically ascertained measures.

Multiple regulatory variants located in cell type-specific enhancers within the PKP2 locus form major risk and protective haplotypes for canine atopic dermatitis in German shepherd dogs.

BACKGROUND Canine atopic dermatitis (CAD) is a chronic inflammatory skin disease triggered by allergic reactions involving IgE antibodies directed towards environmental allergens. We previously identified a ~1.5 Mb locus on canine chromosome 27 associated with CAD in German shepherd dogs (GSDs). Fine-mapping indicated association closest to the PKP2 gene encoding plakophilin 2. RESULTS Additional genotyping and association analyses in GSDs combined with control dogs from five breeds with low-risk for CAD revealed the top SNP 27:19,086,778 (p = 1.4 × 10(-7)) and a rare ~48 kb risk haplotype overlapping the PKP2 gene and shared only with other high-risk CAD breeds. We selected altogether nine SNPs (four top-associated in GSDs and five within the ~48 kb risk haplotype) that spanned ~280 kb forming one risk haplotype carried by 35 % of the GSD cases and 10 % of the GSD controls (OR = 5.1, p = 5.9 × 10(-5)), and another haplotype present in 85 % of the GSD cases and 98 % of the GSD controls and conferring a protective effect against CAD in GSDs (OR = 0.14, p = 0.0032). Eight of these SNPs were analyzed for transcriptional regulation using reporter assays where all tested regions exerted regulatory effects on transcription in epithelial and/or immune cell lines, and seven SNPs showed allelic differences. The DNA fragment with the top-associated SNP 27:19,086,778 displayed the highest activity in keratinocytes with 11-fold induction of transcription by the risk allele versus 8-fold by the control allele (pdifference = 0.003), and also mapped close (~3 kb) to an ENCODE skin-specific enhancer region. CONCLUSIONS Our experiments indicate that multiple CAD-associated genetic variants located in cell type-specific enhancers are involved in gene regulation in different cells and tissues. No single causative variant alone, but rather multiple variants combined in a risk haplotype likely contribute to an altered expression of the PKP2 gene, and possibly nearby genes, in immune and epithelial cells, and predispose GSDs to CAD.

A Study of the Association of Maternal Occupations and Deliveries by Cesarean Section for Infants Born in Washington, 2011-2013

Thesis (Master's)--University of Washington, 2016-06

The consistency of extinction risk classification protocols

Systematic protocols that use decision rules or scores arc, seen to improve consistency and transparency in classifying the conservation status of species. When applying these protocols, assessors are typically required to decide on estimates for attributes That are inherently uncertain, Input data and resulting classifications are usually treated as though they arc, exact and hence without operator error We investigated the impact of data interpretation on the consistency of protocols of extinction risk classifications and diagnosed causes of discrepancies when they occurred. We tested three widely used systematic classification protocols employed by the World Conservation Union, NatureServe, and the Florida Fish and Wildlife Conservation Commission. We provided 18 assessors with identical information for 13 different species to infer estimates for each of the required parameters for the three protocols. The threat classification of several of the species varied from low risk to high risk, depending on who did the assessment. This occurred across the three Protocols investigated. Assessors tended to agree on their placement of species in the highest (50-70%) and lowest risk categories (20-40%), but There was poor agreement on which species should be placed in the intermediate categories, Furthermore, the correspondence between The three classification methods was unpredictable, with large variation among assessors. These results highlight the importance of peer review and consensus among multiple assessors in species classifications and the need to be cautious with assessments carried out 4), a single assessor Greater consistency among assessors requires wide use of training manuals and formal methods for estimating parameters that allow uncertainties to be represented, carried through chains of calculations, and reported transparently.

Nucleic acid amplification testing for Neisseria gonorrhoeae: An ongoing challenge

Nucleic acid amplification tests (NAATs) for the detection of Neisseria gonorrhoeae became available in the early 1990s. Although offering several advantages over traditional detection methods, N. gonorrhoeae NAATs do have some limitations. These include cost, risk of carryover contamination, inhibition, and inability to provide antibiotic resistance data. In addition, there are sequence-related limitations that are unique to N. gonorrhoeae NAATs. In particular, false-positive results are a major consideration. These primarily stem from the frequent horizontal genetic exchange occurring within the Neisseria genus, leading to commensal Neisseria species acquiring N. gonorrhoeae genes. Furthermore, some N. gonorrhoeae subtypes may lack specific sequences targeted by a particular NAAT. Therefore, NAAT false-negative results because of sequence variation may occur in some gonococcal populations. Overall, the N. gonorrhoeae species continues to present a considerable challenge for molecular diagnostics. The need to evaluate N. gonorrhoeae NAATs before their use in any new patient population and to educate physicians on the limitations of these tests is emphasized in this review.

Risk stratification of patients with chronic kidney disease: Results of screening strategies incorporating clinical risk scoring and dobutamine stress echocardiography

Background Cardiac disease is the principal cause of death in patients with chronic kidney disease (CKD). Ischemia at dobutamine stress echocardiography (DSE) is associated with adverse events in these patients. We sought the efficacy of combining clinical risk evaluation with DSE. Methods We allocated 244 patients with CKD (mean age 54 years, 140 men, 169 dialysis-dependent at baseline) into low- and high-risk groups based on two disease-specific scores and the Framingham risk model. All underwent DSE and were further stratified according to DSE results. Patients were followed over 20 +/- 14 months for events (death, myocardial infarction, acute coronary syndrome). Results There were 49 deaths and 32 cardiac events. Using the different clinical scores, allocation of high risk varied from 34% to 79% of patients, and 39% to 50% of high-risk patients had an abnormal DSE. In the high-risk groups, depending on the clinical score chosen, 25% to 44% with an abnormal DSE had a cardiac event, compared with 8% to 22% with a.normal DSE. Cardiac events occurred in 2.0%, 3.1 %, and 9.7% of the low-risk patients, using the two disease-specific and Framingham scores, respectively, and DSE results did not add to risk evaluation in this subgroup. Independent DSE predictors of cardiac events were a lower resting diastolic blood pressure, angina during the test, and the combination of ischemia with resting left ventricular dysfunction. Conclusion In CKD patients, high-risk findings by DSE can predict outcome. A stepwise strategy of combining clinical risk scores with DSE for CAD screening in CKD reduces the number of tests required and identifies a high-risk subgroup among whom DSE results more effectively stratify high and low risk.

Using a clinical pathway and education to reduce inappropriate prescribing of enoxaparin in patients with acute coronary syndromes: a controlled study

Aims: To evaluate efficacy of a pathway-based quality improvement intervention on appropriate prescribing of the low molecular weight heparin, enoxaparin, in patients with varying risk categories of acute coronary syndrome (ACS). Methods: Rates of enoxaparin use retrospectively evaluated before and after pathway implementation at an intervention hospital were compared to concurrent control patients at a control hospital; both were community hospitals in south-east Queensland. The study population was a group of randomly selected patients (n = 439) admitted to study hospitals with a discharge diagnosis of chest pain, angina, or myocardial infarction, and stratified into high, intermediate, low-risk ACS or non-cardiac chest pain: 146 intervention patients (September-November 2003), 147 historical controls (August-December 2001) at the intervention hospital; 146 concurrent controls (September-November 2003) at the control hospital. Interventions were active implementation of a user-modified clinical pathway coupled with an iterative education programme to medical staff versus passive distribution of a similar pathway without user modification or targeted education. Outcome measures were rates of appropriate enoxaparin use in high-risk ACS patients and rates of inappropriate use in intermediate and low-risk patients. Results: Appropriate use of enoxaparin in high-risk ACS patients was above 90% in all patient groups. Inappropriate use of enoxaparin was significantly reduced as a result of pathway use in intermediate risk (9% intervention patients vs 75% historical controls vs 45% concurrent controls) and low-risk patients (9% vs 62% vs 41%; P < 0.001 for all comparisons). Pathway use was associated with a 3.5-fold (95% CI: 1.3-9.1; P = 0.012) increase in appropriate use of enoxaparin across all patient groups. Conclusion: Active implementation of an acute chest pain pathway combined with continuous education reduced inappropriate use of enoxaparin in patients presenting with intermediate or low-risk ACS.

Fetal growth patterns in fetuses of women with pregestational diabetes mellitus

Objective To assess the effect of glucose control on the rate of growth of fetuses in women with pregestational diabetes mellitus (Types 1 and 2). Methods All pregestational diabetic women booked at Mater Mothers’ Hospital, Brisbane, Australia, between 1 January 1994 and 31 December 2002, were included. Pregnancies with congenital fetal anomalies, multiple pregnancies, and pregnancies terminated prior to 20 weeks’ gestation were excluded. Dating scans were performed before 14 weeks’ gestation and serial scans were performed at 18, 24, 28, 32 and 36 weeks. Fetal parameters, including biparietal diameter, femur length and abdominal circumference, were recorded. The daily growth rates for biparietal diameter, femur length, and fetal abdominal area were calculated and compared with those in a low-risk (non-diabetic) population. The growth rates in fetuses of women with satisfactory diabetic control (HbA1c

Comparison of estimates and calculations of risk of coronary heart disease by doctors and nurses using different calculation tools in general practice: cross sectional study

OBJECTIVE: To assess the effect of using different risk calculation tools on how general practitioners and practice nurses evaluate the risk of coronary heart disease with clinical data routinely available in patients' records. DESIGN: Subjective estimates of the risk of coronary heart disease and results of four different methods of calculation of risk were compared with each other and a reference standard that had been calculated with the Framingham equation; calculations were based on a sample of patients' records, randomly selected from groups at risk of coronary heart disease. SETTING: General practices in central England. PARTICIPANTS: 18 general practitioners and 18 practice nurses. MAIN OUTCOME MEASURES: Agreement of results of risk estimation and risk calculation with reference calculation; agreement of general practitioners with practice nurses; sensitivity and specificity of the different methods of risk calculation to detect patients at high or low risk of coronary heart disease. RESULTS: Only a minority of patients' records contained all of the risk factors required for the formal calculation of the risk of coronary heart disease (concentrations of high density lipoprotein (HDL) cholesterol were present in only 21%). Agreement of risk calculations with the reference standard was moderate (kappa=0.33-0.65 for practice nurses and 0.33 to 0.65 for general practitioners, depending on calculation tool), showing a trend for underestimation of risk. Moderate agreement was seen between the risks calculated by general practitioners and practice nurses for the same patients (kappa=0.47 to 0.58). The British charts gave the most sensitive results for risk of coronary heart disease (practice nurses 79%, general practitioners 80%), and it also gave the most specific results for practice nurses (100%), whereas the Sheffield table was the most specific method for general practitioners (89%). CONCLUSIONS: Routine calculation of the risk of coronary heart disease in primary care is hampered by poor availability of data on risk factors. General practitioners and practice nurses are able to evaluate the risk of coronary heart disease with only moderate accuracy. Data about risk factors need to be collected systematically, to allow the use of the most appropriate calculation tools.

An initial evaluation of gellan gum as a material for tissue engineering applications

Alpha-modified minimum essential medium (αMEM) has been found to cross-link a 1% gellan gum solution, resulting in the formation of a self-supporting hydrogel in 1:1 and 5:1 ratios of polysaccharide: αMEM. Rheological data from temperature sweeps confirm that in addition to orders of magnitude differences in G' between 1% gellan and 1% gellan with αMEM, there is also a 20°C increase in the temperature at which the onset of gelation takes place when αMEM is present. Frequency sweeps confirm the formation of a true gel; mechanical spectra for mixtures of gellan and αMEM clearly demonstrate G' to be independent of frequency. It is possible to immobilize cells within a three-dimensional (3D) gellan matrix that remain viable for up to 21 days in culture by adding a suspension of rat bone marrow cells (rBMC) in αMEM to 1% gellan solution. This extremely simple approach to cell immobilization within 3D constructs, made possible by the fact that gellan solutions cross-link in the presence of millimolar concentrations of cations, poses a very low risk to a cell population immobilized within a gellan matrix and thus indicates the potential of gellan for use as a tissue engineering scaffold. © 2007 Sage Publications.

Bayesian neural network approach for determining the risk of re-intervention after endovascular aortic aneurysm repair

This article proposes a Bayesian neural network approach to determine the risk of re-intervention after endovascular aortic aneurysm repair surgery. The target of proposed technique is to determine which patients have high chance to re-intervention (high-risk patients) and which are not (low-risk patients) after 5 years of the surgery. Two censored datasets relating to the clinical conditions of aortic aneurysms have been collected from two different vascular centers in the United Kingdom. A Bayesian network was first employed to solve the censoring issue in the datasets. Then, a back propagation neural network model was built using the uncensored data of the first center to predict re-intervention on the second center and classify the patients into high-risk and low-risk groups. Kaplan-Meier curves were plotted for each group of patients separately to show whether there is a significant difference between the two risk groups. Finally, the logrank test was applied to determine whether the neural network model was capable of predicting and distinguishing between the two risk groups. The results show that the Bayesian network used for uncensoring the data has improved the performance of the neural networks that were built for the two centers separately. More importantly, the neural network that was trained with uncensored data of the first center was able to predict and discriminate between groups of low risk and high risk of re-intervention after 5 years of endovascular aortic aneurysm surgery at center 2 (p = 0.0037 in the logrank test).