Author Correction: Mapping the world's free-flowing rivers.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Mapping the world's free-flowing rivers.

Free-flowing rivers (FFRs) support diverse, complex and dynamic ecosystems globally, providing important societal and economic services. Infrastructure development threatens the ecosystem processes, biodiversity and services that these rivers support. Here we assess the connectivity status of 12 million kilometres of rivers globally and identify those that remain free-flowing in their entire length. Only 37 per cent of rivers longer than 1,000 kilometres remain free-flowing over their entire length and 23 per cent flow uninterrupted to the ocean. Very long FFRs are largely restricted to remote regions of the Arctic and of the Amazon and Congo basins. In densely populated areas only few very long rivers remain free-flowing, such as the Irrawaddy and Salween. Dams and reservoirs and their up- and downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity. By applying a new method to quantify riverine connectivity and map FFRs, we provide a foundation for concerted global and national strategies to maintain or restore them.

Infraclavicular anterior thoracic approach for access to the upper thoracic vertebrae: case report and description of a new surgical technique.

Patient with spondylodiscitis who presented kyphosis deformity with neurological compromise at the upper thoracic level, who was treated with a new right infraclavicular anterior thoracic approach, as a new alternative surgical technique. 72-year-old male with kyphosis deformity secondary to T2-T3 ASIA "C" spondylodiscitis, treated with C5 to T6 posterior cervicothoracic instrumentation and right infraclavicular transthoracic anterior approach utilizing an expandable cylinder. Within the literature review carried out in the search engines, no similar techniques to the one described in this article were found. Given the complexity of the surgical approach, this new technique is described as a new way for accessing the upper thoracic spine, demonstrating that the right infraclavicular anterior thoracic approach is a new alternative to access the upper thoracic spine from T1 to T4.

Paciente con espondilodiscitis que presentó deformidad cifótica con compromiso neurológico a nivel torácico superior, quien fue tratado con un nuevo abordaje torácico anterior infraclavicular derecho, como nueva técnica quirúrgica alternativa. Varón de 72 años con deformidad en cifosis secundaria a espondilodiscitis T2-T3 ASIA "C", tratado con instrumentación cervicotorácica posterior C5 a T6 y abordaje anterior transtorácico infraclavicular derecho con colocación de cilindro expandible. Dentro de la revisión bibliográfica realizada en los buscadores no se encontraron técnicas similares a la descrita en este artículo. Dada la complejidad del abordaje quirúrgico, esta nueva técnica se describe como una nueva forma de acceder a la columna torácica superior, demostrando que el abordaje torácico anterior infraclavicular derecho es una nueva alternativa para acceder a la columna torácica superior desde T1 a T4.

Endogenous cytokinins in Cocos nucifera L. in vitro cultures obtained from plumular explants.

Auxin induces in vitro somatic embryogenesis in coconut plumular explants through callus formation. Embryogenic calli and non-embryogenic calli can be formed from the initial calli. Analysis of endogenous cytokinins showed the occurrence of cytokinins with aromatic and aliphatic side chains. Fourteen aliphatic cytokinins and four aromatic cytokinins were analysed in the three types of calli and all the cytokinins were found in each type, although some in larger proportions than others. The most abundant cytokinins in each type of callus were isopentenyladenine-9-glucoside, zeatin-9-glucoside, zeatin riboside, isopentenyladenine riboside, dihydrozeatin and dihydrozeatin riboside in decreasing order. Total cytokinin content was compared between the three types of calli, and it was found to be lower in embryogenic calli compared to non-embryogenic calli or initial calli. The same pattern was observed for individual cytokinins. When explants were cultured in media containing exogenously added cytokinins, the formation of embryogenic calli in the explants was reduced. When 8-azaadenine (an anticytokinin) was added the formation of embryogenic calli and somatic embryos was increased. These results suggest that the difference in somatic embryo formation capacity observed between embryogenic calli and non-embryogenic calli is related to their endogenous cytokinin contents.

Donors Older Than 75 Years Do Not Influence the Appearance of Biliary Complications After Liver Transplantation.

BACKGROUND: In recent years, several studies have shown that the age of the donor may be related to an increase in the occurrence of biliary complications (BCs), which remain the main cause of morbidity after liver transplantation. This study analyzed the type and management of these BCs, the impact of BCs on graft and patient survival rates, and the influence of some characteristics of donors and recipients on BC appearance in patients transplanted with donors 75 years of age or older. PATIENTS AND METHODS: From 2003 to 2016, 100 liver transplantations with donors 75 years of age or older (15.6%) were performed in our hospital. The data were compared with a control group of 400 patients with younger donors (case-control 1:4 per chronology). RESULTS: The BC rate in the group of patients transplanted with organs from elderly donors was 18%, compared to 21.5% in the control group. Specifically, in the immediate post-transplantation period, 14% of the elderly donor group and 13.8% of the control group presented some BCs, with no statistically significant differences in the incidence, type, and treatment of BCs between the two groups. The occurrence of BCs was not a factor associated with graft and patient survival rates. In the global population, donor death by cerebral vascular accident and male donors have influenced the occurrence of BCs. CONCLUSIONS: The advanced age of the donor has not influenced BC rates after transplantation.

Matrix Metalloproteinase 1 as a Novel Biomarker for Monitoring Hepatocellular Carcinoma in Liver Transplant Patients.

INTRODUCTION: Orthotopic liver transplantation (LT) is considered to be one of the few curative treatments available for early stages of hepatocellular carcinoma (HCC). Alfa-fetoprotein (AFP) is the most-used biomarker for HCC despite low sensitivity and specificity. Matrix metalloproteinase 1 (MMP-1) has been considered to be involved in the process of vascular invasion of the malignant cells. The objective of this study was to assess the use of MMP-1 for the management of HCC patients for LT. METHODS: Levels in serum of MMP-1 (ng/mL) and AFP (ng/mL) were assessed in 20 HCC patients (Milan criteria) before and 1, 6, and 12 months after LT. RESULTS: There was a strong significant correlation between levels of MMP-1 and levels of AFP (ρ = .954; P ≤ .05). There were statistical differences in the levels of MMP-1 and APF between the pre-transplantation and post-transplantation groups (1 and 12 months). Increments of both markers 6 months after LT compared with the levels 1 month after LT were detected in 4 of the 20 HCC patients. The detection of recurrence by means of imaging was coincident with the increment of both markers 6 months after LT in 3 of those 4 patients. CONCLUSIONS: After 12 months of follow-up, levels of MMP-1 were comparable to AFP levels after LT. Levels of both markers increase 6 months after LT in patients showing recurrence, indicating discriminatory power to predict relapse and thus serving as valuable markers for HCC monitoring. MMP-1 could be useful in the management of HCC after LT.

[Executive functions and high intellectual capacity]. / Funciones ejecutivas y alta capacidad intelectual.

INTRODUCTION: High intellectual capacity is a process in development in which the executive functions (inhibition, working memory and flexibility) play a role in the optimal manifestation of their potential. AIM: To explore the effectiveness of executive functioning among the profiles of high capacity giftedness and (convergent or divergent) talent. SUBJECTS AND METHODS: The study examines 78 children with high intellectual capacity aged 8-15 years with profiles of giftedness (n = 21), convergent talent (n = 39) or divergent talent (n = 18). A series of tests were administered including the Battery of Differential and General Aptitudes or the Differential Aptitude Test (depending on the age) and the Torrance Test of Creative Thinking, as well as the Wisconsin Card Sorting Test, the Corsi Test and the Go-No Go Test by means of the Psychology Experiment Building Language platform. A multivariate analysis of variance was performed to determine the relationship between executive function and intellectual profile. RESULTS: Significant differences are obtained between the profiles studied and the executive functions of flexibility and inhibition, but not in working memory. CONCLUSION: Working memory is similar across the profiles studied, but the complex profile of giftedness displays better executive functioning, with greater flexibility and inhibition than talent, especially of the convergent type.

TITLE: Funciones ejecutivas y alta capacidad intelectual.Introduccion. La alta capacidad intelectual es un proceso en desarrollo en el que las funciones ejecutivas (inhibicion, memoria de trabajo y flexibilidad) desempeñan un papel en la manifestacion optima de su potencial. Objetivo. Explorar la eficacia del funcionamiento ejecutivo entre los perfiles de alta capacidad de superdotacion y talento (convergente o divergente). Sujetos y metodos. Se estudiaron 78 niños con alta capacidad intelectual de 8-15 años con perfiles de superdotacion (n = 21), talento convergente (n = 39) o talento divergente (n = 18). Se administro la bateria de aptitudes diferenciales y generales o el Differential Aptitude Test (segun la edad) y el test de pensamiento creativo de Torrance, ademas del test de clasificacion de tarjetas de Wisconsin, el test de Corsi y el test go-no go mediante la plataforma Psychology Experiment Building Language. Se realizo un analisis multivariado de la varianza para conocer la relacion entre funcion ejecutiva y perfil intelectual. Resultados. Se obtienen diferencias significativas entre los perfiles estudiados y las funciones ejecutivas de flexibilidad e inhibicion, pero no en la memoria de trabajo. Conclusion. La memoria de trabajo es similar entre los perfiles estudiados, pero el perfil complejo de superdotacion muestra mejor funcionamiento ejecutivo, con mayor flexibilidad e inhibicion que el talento, especialmente el convergente.

Oncological Evaluation by Positron-emission Tomography, Circulating Tumor Cells and Alpha Fetoprotein in Patients With Hepatocellular Carcinoma on the Waiting List for Liver Transplantation.

INTRODUCTION: The objectives of this study are the determination of the number of circulating tumor cells (CTCs), by means of the IsoFlux enrichment system (Fluxion Biosciences Inc, San Francisco, California, United States) in patients with hepatocellular carcinoma (HCC) in compliance with the Milan criteria and on the waiting list for hepatic transplantation, as well as the study of its relation with the of α-fetoprotein levels (AFP) and positron-emission tomography-computed tomography (PET-CT) findings. PATIENTS AND METHODS: An oncologycal evaluation with PET-CT, CTCs, and AFP was conducted in 24 consecutive patients with HCC eligible for orthotopic liver transplantation according to the Milan criteria. The diagnosis of HCC was made according to clinical, biological, and radiological findings. RESULTS: We detected CTCs in peripheral blood in 21 of 24 patients (87.5%) before liver transplantation, with a mean number CTCs of 156 ± 370 (range, 2 to 1768) with statistically significant association between number of CTCs detected in peripheral blood and the time within the waiting list (P < .05), but not betwen AFP levels and standard uptake value and time to orthotopic liver transplantation (P > .05). CONCLUSIONS: PET-TC, CTCs, and AFP levels could be an essential key for the correct management of the patients with HCC on the waiting list for liver transplantation.

Comparison of Two Types of Liquid Biopsies in Patients With Hepatocellular Carcinoma Awaiting Orthotopic Liver Transplantation.

INTRODUCTION: Orthotopic liver transplantation (OLT) is considered one of the few curative treatments available for early stages of hepatocellular carcinoma (HCC). It has been shown that more than 10% of transplanted individuals suffer relapse during the first year after surgery and most of them die because of the tumor. The circulating tumor cells (CTCs) are the main source of recurrences as they disseminate from a primary or metastatic tumor lesion through peripheral blood. We aimed to determine the concentration of CTCs in peripheral blood in these patients by 2 different approaches: the CellSearch and the IsoFlux systems to assess their applicability to this disease monitoring. PATIENTS AND METHODS: A comparative study was conducted in 21 patients with HCC eligible for liver transplantation according to the Milan criteria, whose peripheral blood was processed by the CellSearch and the IsoFlux systems. RESULTS: CTCs were isolated in 1 of the 21 patients (4.7%) by the CellSearch system and in 19 of the 21 patients (90.5%) by the IsoFlux method. The comparison of both methods using Bland-Altman plot shows that there is not consistency in the determination of CTCs in our patients, finding a proportional bias between them. CONCLUSION: The results obtained by both CTCs isolation systems are not interchangeable nor transferable. The CellSearch system does not seem to be the ideal approach for studying CTCs in patients with HCC. The IsoFlux system displays greater sensitivity in the identification of CTCs and might become an important tool in patient management.

Regeneration of coconut (Cocos nucifera L.) from plumule explants through somatic embryogenesis.

A protocol was developed for coconut regeneration using plumules from mature zygotic embryos as explants, and media with the synthetic growth regulators 2,4-dichlorophenoxyacetic acid and 6-benzylaminopurine. Evidence for the regeneration process from these tissues occurring through somatic embryogenesis is presented. The somatic embryos were capable of germination, subsequent development into plantlets and successful transfer to the nursery. The yields were larger, nearly twofold for calli and over tenfold for calli bearing somatic embryos, than those previously reported with inflorescence explants. The present protocol thus represents an improvement in time and yield over previous protocols. Even though plumule explants are not the ideal tissue source due to possible genetic heterogeneity, the improvements made here may be applicable to tissues from mature plants. In addition, micropropagation of coconut using plumules is potentially useful when they are obtained from fruit produced from selected parents of outstanding performance, such as those resistant to diseases.

[Long-term efficacy of radiofrequency catheter ablation in atrial tachycardia]. / Eficacia a largo plazo de la ablación con radiofrecuencia en la taquicardia auricular.

INTRODUCTION AND OBJECTIVES: Radiofrequency ablation has shown to be an effective treatment for supraventricular tachycardias including flutter and atrial tachycardia, however the clinical information available on atrial tachycardia is limited. The aim of this study was to evaluate the immediate and long term effectiveness of radiofrequency ablation in patients with atrial tachycardia and to establish predictors of effectiveness and arrhythmia recurrence. METHODS: We analyzed a series of 126 procedures of atrial tachycardia ablation in 117 patients (69% women) with a mean age of 50 +/- 19 years. RESULTS: Ninety-one percent of the foci were located in the right atrium. A mean of 6 applications were necessary to achieve an efficacy of 74% during the first procedure with a total of 80%. The only predictor of ablation success was the number of foci being smaller in multifocal compared to unifocal (p < 0.01) whereas for recurrences a less premature electrogram at the application point (p = 0.02) was predictive of ablation success. Over a follow-up of 34 +/- 19 months 7.4% of patients had recurrent atrial tachycardia. The probability of recurrence at one year calculated by the Kaplan-Meier method was 12%. Seventy-one percent of the recurrences occurred during the first 3 months after ablation. CONCLUSIONS: Ablation is an effective, safe procedure for short and long term treatment of patients with atrial tachycardia. Effectiveness depends on the number of foci while the recurrence rate is related to the prematurity of atrial electrogram at the application point.

Evaluation of glucose as a cryoprotectant for boar semen.

Fertility parameters of boar spermatozoa were evaluated in vitro, after freeze-thawing the semen in three different extenders containing permeable and non-permeable cryoprotectants: A (111.0 mM Tris, 31.4 mM citric acid, 185.0 mM glucose, 20 per cent egg yolk, 3 per cent glycerol and 100 iu/ml penicillin G); B (200 mM Tris; 70.8 mM citric acid, 55.5 mM glucose, 20 per cent egg yolk, three per cent glycerol and 100 iu/ml penicillin G); C (200 mM Tris, 70.8 mM citric acid, 55.5 mM fructose, 20 per cent egg yolk, 3 per cent glycerol and 100 iu/ml penicillin G). The freeze-thawing techniques were the same for each extender. Eight ejaculates from four boars were obtained; the sperm-rich fraction of each ejaculate was extended in each of the three media at a final concentration of 400 x 106 sperm/ml, loaded into 0.5 ml straws and frozen at a rate of 30 degrees C/minute to -196 degrees C. The straws were thawed at 60 degrees C for eight seconds. Sperm motility, acrosomal integrity and in vitro sperm penetration through the zona pellucida of gilt oocytes matured in vitro were evaluated. The motility of unfrozen spermatozoa was 93.1 per cent compared with 60.7 per cent, 48.2 per cent and 35 per cent for sperm frozen in extenders A, B and C respectively; these values were all significantly different (P<0.05). There was no significant decline in sperm motility after incubation for 30 minutes in extender A, but there were significant decreases in sperm motility after 30 minutes of incubation in B and C. The percentage acrosomal integrities were 97.2 per cent for the control and 45.5 per cent, 30.3 per cent and 16.8 per cent for the frozen-thawed spermatozoa in extenders A, B and C respectively. The results of the in vitro penetration assay were 80.7 per cent when using control spermatozoa, and 42.2 per cent, 18.4 per cent and 3.3 per cent when using frozen-thawed spermatozoa in extenders A, B and C respectively

[Usefulness of troponin T and troponin I in the diagnosis and prognostic stratification of patients with ischemic cardiopathy attending an emergency service]. / Utilidad de la troponina T y troponina I en el diagnóstico y estratificación pronóstica de los pacientes con cardiopatía isquémica que acuden a un Servicio de Urgencias.

BACKGROUND: Diagnostic of chest pain in the emergency services supposes a serious problem. This study wants objective if the new non enzymatic markers of myocardial necrosis (T troponin and I troponin) may be an aid for the diagnostic and prognostic stratification of patients with myocardial ischemia. PATIENTS AND METHODS: 82 successive patients who went to the emergency room for chest pain were studied. Electrocardiogram and blood samples were obtained at 0,4, and 12 house of admission. A clinic-evolutive study was performed at discharge, and they were classified in 3 categories: a) myocardial infarction, b) unstable angina (Braunwald classification) and no coronary pains. RESULTS: In the 27 patients with myocardial infarction the markers of troponin group were more sensitive than creatinine kinase to determine myocardial necrosis at 4 hours of admission. Of 41 patients with unstable angina, 34% were of Braunwald III-B class. Troponin group markers discriminate a group of high risk patients, 70% of the patients that need an emergency coronarography for bad clinical evolution were troponin group marker positive. CONCLUSIONS: The use in the emergency room of troponin necrosis markers (T and I troponin) allows to optimize the sanitary resources, detecting quickly the patients with acute myocardial infarction and discriminate a group of high risk of patients with angina.

[Nutrition programs and levels of health care]. / Actividades de nutrición y niveles de atención en salud.

Population health and nutrition situations present different degrees of complexity which must be met with different degrees of technological complexity. This can be accomplished by organizing, in a progressive way, the resources of the health service system to constitute different levels of attention. In this paper, the concept of levels of attention of the health service system is analyzed on the basis of the aforementioned ideas, and comments are made on the increasing administrative complexity required to keep pace with the increasing technological complexity. Mention is made of the criteria which must be taken into account in order to select nutrition activities to be performed in the health sector and the way in which these activities must conform to the different levels, according to their degree of specialization and complexity. Special reference is made of experiences where the basic or primary level activities involving community participation are particularly important. Finally, the incorporation of nutrition as a part of the attention routine at the various levels is discussed; here, the importance of the necessary mechanisms for coordination and support among the various levels is stressed.

[The health sector in the multisectorial planning for food and nutrition]. / El sector salud en la planificación multisectorial de la alimentación y nutrición.

The limited success of the health unisectorial action for the solution of the nutritional problems of the population led to the recognition of the necessity of coordinating the work of many sectors. The most important responsibilities of the health sector in the process of the multisectorial food and nutrition planning are discussed: morail and technical leadership during the promotion and development of the process: diagnosis of the nutritional problems; definition of the biological reference terms; promotion and participation in the design, initiation, operation and evaluation of food and nutrition multisectorial systems; participation in the formulation of socio-economical development objectives; evaluation of the food and nutrition policies, and follow-up and evaluation of the projects they may generate; active participation and support of resources for the development of the process; implementation and execution of the sectoral activities; research; participation in nutritional planning aspects for disaster situations, and planning of the nutritional activities of the health sector.

[Demographic dynamics in the food-nutrition problem: the search for effective strategies in Latin America]. / La dinámica demográfica en la problemática alimentaria-nutricional: la búsqueda de estrategias effectiv as en América Latina.

This paper addresses the interrelationship between the food and nutrition problem and population problems in Latin America within a global focus. A basic framework is presented which defines four demographic problems highly related with the food and nutrition situation: The underutilization of the labor force; the accelerated growth of the marginal population; the poor geographic distribution and rapid urbanization; and the high rates of infant and child mortality. Findings from the recent experience of demography in food and nutrition planning in the last four years in Central America and Panama are outlined, and strategies are recommended for the development of different types of programs and projects in population-nutrition. Finally, a list of applied research, basic information and direct action projects in population-nutrition that have been detected as needed by most of the Central American countries, is presented.

PIP: This paper explores various strategies for development of more effective integrated programs of nutrition and population, based on the study of the interrelationship between the 2 problems and the experience acquired in the application of population studies to the process of food and nutrition planning in Central America and Panama. An implicit consensus has been reached that the major problems which confront Latin American governments as a result of present demographic and social trends are urban concentration and metropolization, underutilization of the labor force, extreme poverty, and insufficient basic services. Many existing studies of the links between population, nutrition, and socioeconomic development have had perspectives that have been too global or too partial to support policymaking and planning. Some new lines of study of women, the family, basic needs and extreme poverty, on 1 side, and the elaboration of diagnostic tools, target groups, goals, primary health interventions, integral rural development, and their evaluation, on the other, represent advances in the integration of population and nutrition problems into development planning. A model of interrelationships between demographic policies, malnutrition, and socioeconomic development gives highest priority to 4 demographic problems affecting nutrition: underutilization of the labor force, which affects purchasing power and consumption; growth of the marginal sector, poor population distribution and rapid urbanization; and high mortality among children under 5. A project developed in Central America and Panama from 1977-79 on the sociodemographic dimensions of food and nutrition planning was largely intended to improve institutional planning capacity. An illustrative table identifies 4 conditioning factors of malnutrition, including lack of adequate planning, insufficient food production and poor distribution and underutilization of available food by the body; provides examples of nutritional programs directed toward the problems, and lists expected effects of the programs on demographic variables. Another table outlines conditioning factors of malnutrition and related demographic variables. 5 areas requiring research in Central America are seasonal migration and malnutrition; malnutrition and infant mortality; composition and stability of the family and intrafamily food distribution; urban women's role and lactation; and agricultural density, rural displacement, and home production.

Evaluation of a multilayered chitosan-hydroxy-apatite porous composite enriched with fibronectin or an in vitro-generated bone-like extracellular matrix on proliferation and diferentiation of osteoblasts.

The use of extracellular matrix (ECM) molecules from tissues is an interesting way to induce specific responses of cells grown onto composite scaffolds to promote adhesion, proliferation and differentiation. There have been several studies on the effects on cell proliferation and differentiation of osteoprogenitor cells cultured onto composites, either adding some ECM molecules or grown in the presence of growth factors. Other studies involve the use of osteoblasts cultured on a three-dimensional (3D) matrix, enriched with ECM molecules produced by the same cells grown previously inside the composite. Here, the effect of enrichment of a novel multilayered chitosan-hydroxyapatite composite with ECM molecules produced by osteoblasts, or the addition of 25 or 50 µg/ml fibronectin to the composite, on proliferation and differentiation of osteoblasts cultured on these composites was studied. The results showed an increase in the number of osteoblasts from day 1 of culture, which was higher in the group grown onto composites enriched with the highest concentration of fibronectin or with ECM molecules produced naturally by osteoblasts cultured previously on them, when compared with the control group. However, this increment tended to decline in all groups after day 7 of culture, the day when they reached the highest peak of proliferation. Differentiation expressed as alkaline phosphatase activity followed the proliferation pattern of the cells cultivated on the scaffolds. The results demonstrate the potential offered by these enriched 3D multilayered composites for improving their ability as bone grafting material.