Ambush strategy enhances organisms' performance in rock-paper-scissors games.

We study a five-species cyclic system wherein individuals of one species strategically adapt their movements to enhance their performance in the spatial rock-paper-scissors game. Environmental cues enable the awareness of the presence of organisms targeted for elimination in the cyclic game. If the local density of target organisms is sufficiently high, individuals move towards concentrated areas for direct attack; otherwise, they employ an ambush tactic, maximising the chances of success by targeting regions likely to be dominated by opponents. Running stochastic simulations, we discover that the ambush strategy enhances the likelihood of individual success compared to direct attacks alone, leading to uneven spatial patterns characterised by spiral waves. We compute the autocorrelation function and measure how the ambush tactic unbalances the organisms' spatial organisation by calculating the characteristic length scale of typical spatial domains of each species. We demonstrate that the threshold for local species density influences the ambush strategy's effectiveness, while the neighbourhood perception range significantly impacts decision-making accuracy. The outcomes show that long-range perception improves performance by over 60%, although there is potential interference in decision-making under high attack triggers. Understanding how organisms' adaptation their environment enhances their performance may be helpful not only for ecologists, but also for data scientists, aiming to improve artificial intelligence systems.

Influence of the river flow pulse on the maturity, resilience, and sustainability of tropical coastal ecosystems.

Coastal marine ecosystems have structural and functional features usually connected by the seasonal transfer of nutrients and organisms. These environments can utilize inter-ecosystem subsidies to increase resilience and maturity and support human activities like fishing. However, the importance of the connection and the role of the seasonal pulse of energy flows to enhance maturity are still poorly understood and reported. Our objective in this paper is to assess the effect of seasonal hydrological pulses on two tropical coastal interconnected ecosystems. Thus, we made four Ecopath models for estuarine and neritic environments considering the dry and rainy seasons, with a similar sampling design that allowed them to be compared. Our results provide evidence for the occurrence of the pulsed ecosystems since both environments seem driven by the river flow. Estuary presents more and more substantial differences (measured by ecosystem attributes) in both seasons because it is directly affected by river floods than the neritic environment. The neritic is affected indirectly by the movement of species from the estuary and by a weaker river flow. In the dry season, the differences between ecosystems are lower because the dry season trend to homogenize cycling, maturity, homeostasis, and resilience. We found that the seasonal river flow (pulse) forces the variability of biomass, flows, and ecosystem features, and this variance creates the required stability for both ecosystems. Still, these environments benefit through the exchange of components that relieve the pressures of predation on specific groups and maintain the energy flow necessary for the functioning of their trophic webs. The pulse by the rainfall favors connectivity and equalizes the two systems, increasing the connectivity between them and the exchange of subsidies that strengthens the trophic structures, contributing to the increase in maturity. In these ecosystems, seasonal changes become a key factor for exchanging flows that will promote sustainability, the accumulation of more biomass (growth), and the optimization of reserve energy (development) in both systems. This efficient joint strategy of perpetuation is what promotes resistance and resilience to these ecosystems, which together can reach different states of equilibrium, translated into maturity to withstand new environmental changes.

How local antipredator response unbalances the rock-paper-scissors model.

Antipredator behavior is a self-preservation strategy present in many biological systems, where individuals join the effort in a collective reaction to avoid being caught by an approaching predator. We study a nonhierarchical tritrophic system, whose predator-prey interactions are described by the rock-paper-scissors game rules. We perform a set of spatial stochastic simulations where organisms of one out of the species can resist predation in a collective strategy. The drop in predation capacity is local, which means that each predator faces a particular opposition depending on the prey group size surrounding it. Considering that the interference in a predator action depends on the prey's physical and cognitive ability, we explore the role of a conditioning factor that indicates the fraction of the species apt to perform the antipredator strategy. Because of the local unbalancing of the cyclic predator-prey interactions, departed spatial domains mainly occupied by a single species emerge. Unlike the rock-paper-scissors model with a weak species because of a nonlocal reason, our findings show that if the predation probability of one species is reduced because individuals face local antipredator response, the species does not predominate. Instead, the local unbalancing of the rock-paper-scissors model results in the prevalence of the weak species' prey. Finally, the outcomes show that local unevenness may jeopardize biodiversity, with the coexistence being more threatened for high mobility.

Colistimethate sodium and acute kidney injury: Incidence, risk factors, outcome and prognosis of renal function / Fracaso renal agudo y colistimetato de sodio: incidencia, factores de riesgo, resultados y pronóstico de la función renal

BACKGROUND: Colistimethate sodium (CMS) treatment has increased over the last years, being acute kidney injury (AKI) its main drug-related adverse event. Therefore, this study aimed to evaluate the incidence and risk factors associated with AKI, as well as identifying the factors that determine renal function (RF) outcomes at six months after discharge. MATERIALS AND METHODS: This retrospective study included adult septic patients receiving intravenous CMS for at least 48 h (January 2007-December 2014). AKI was assessed using KDIGO criteria. The glomerular filtration rate (GFR) was estimated by the 4-variable MDRD equation. Logistic and linear models were performed to evaluate the risk factors for AKI and chronic kidney disease (CKD). RESULTS: Among 126 patients treated with CMS; the incidence of AKI was 48.4%. Sepsis-severe sepsis (OR 8.07, P = 0.001), sepsis-septic shock (OR 42.9, P < 0.001), and serum creatinine (SCr) at admission (OR 6.20, P = 0.009) were independent predictors. Eighty-four patients survived; the main factors for RF evolution at the 6-month follow-up was baseline eGFR (0.58, P < 0.001) and at discharge (0.34, P < 0.001). Fifty-six percent (34/61) of the patients that developed AKI survived. At six months, 32% had CKD. CONCLUSIONS: The development of AKI in septic patients with CMS treatment was associated with sepsis severity and SCr at admission. Baseline eGFR and eGFR at discharge were and important determinant of the RF at the 6-month follow-up. These predictors may assist in clinical decision making for this patient population

INTRODUCCIÓN: El tratamiento con colistimetato de sodio (CMS) se ha incrementado, siendo su principal complicación el fracaso renal agudo (FRA). El objetivo de este estudio fue determinar la incidencia de FRA y los factores de riesgo asociados, así como identificar los factores que determinan la función renal (FR) a los 6 meses del alta hospitalaria. MATERIALES Y MÉTODOS: Estudio retrospectivo que incluyó pacientes adultos sépticos que recibieron CMS intravenoso durante al menos 48 h (enero 2007-diciembre 2014). El diagnóstico de FRA se realizó según los criterios KDIGO. Se estimó el filtrado glomerular (FG) mediante la ecuación del MDRD-4. Se realizaron modelos logísticos y lineales para evaluar los factores de riesgo para el desarrollo de FRA y enfermedad renal crónica (ERC). RESULTADOS: Ciento veintiséis pacientes fueron incluidos; la incidencia de FRA fue del 48,4%. Sepsis-sepsis severa (OR: 8,07; p = 0,001), sepsis-shock séptico (OR: 42,9; p < 0,001) y la creatinina sérica (CRs) al ingreso (OR: 6,20; p = 0,009) fueron predictores independientes de FRA. Ochenta y cuatro pacientes sobrevivieron; el determinante principal de la evolución de la FR a los 6 meses de seguimiento fue el FGe basal (0,58; p < 0,001) y al alta (0,34; p < 0,001). El 56% (34/61) de los pacientes que desarrollaron FRA sobrevivieron. A los 6 meses, el 32% desarrollo ERC. CONCLUSIONES: El desarrollo de FRA asociado al tratamiento con CMS se asoció con el grado de severidad de la sepsis y la CRs al ingreso. El FGe basal y al alta hospitalaria fueron predictores independientes de la FR a los 6 meses de seguimiento

Colistimethate sodium and acute kidney injury: Incidence, risk factors, outcome and prognosis of renal function.

BACKGROUND: Colistimethate sodium (CMS) treatment has increased over the last years, being acute kidney injury (AKI) its main drug-related adverse event. Therefore, this study aimed to evaluate the incidence and risk factors associated with AKI, as well as identifying the factors that determine renal function (RF) outcomes at six months after discharge. MATERIALS AND METHODS: This retrospective study included adult septic patients receiving intravenous CMS for at least 48h (January 2007-December 2014). AKI was assessed using KDIGO criteria. The glomerular filtration rate (GFR) was estimated by the 4-variable MDRD equation. Logistic and linear models were performed to evaluate the risk factors for AKI and chronic kidney disease (CKD). RESULTS: Among 126 patients treated with CMS; the incidence of AKI was 48.4%. Sepsis-severe sepsis (OR 8.07, P=0.001), sepsis-septic shock (OR 42.9, P<0.001), and serum creatinine (SCr) at admission (OR 6.20, P=0.009) were independent predictors. Eighty-four patients survived; the main factors for RF evolution at the 6-month follow-up was baseline eGFR (0.58, P<0.001) and at discharge (0.34, P<0.001). Fifty-six percent (34/61) of the patients that developed AKI survived. At six months, 32% had CKD. CONCLUSIONS: The development of AKI in septic patients with CMS treatment was associated with sepsis severity and SCr at admission. Baseline eGFR and eGFR at discharge were and important determinant of the RF at the 6-month follow-up. These predictors may assist in clinical decision making for this patient population.

Optimization of hot-air drying conditions for cassava flour for its application in gluten-free pasta formulation.

The design and development of gluten-free foods requires a comprehensive understanding of the behavior of the raw materials to attain the same cooking and nutritional quality as gluten-based food. The objective of this study was to determine the optimal hot-air drying conditions for elaboration of cassava flour to be used in a gluten-free pasta formulation. The results showed that the operational conditions to minimize the hot-air drying time (57 min) to produce cassava flour with higher water holding capacity was 57 ℃ at 3 m/s. Then, the optimal formulation for the pasta was found to be cassava (26 g/100 g), amaranth flour (12 g/100 g), and carboxymethyl cellulose (0.23 g/100 g), which maximized the Aw (0.160), moisture content (3.10 g/100 g), hardness (5.02 N), and protein content (9.30 g/100 g), and it is used for the sensorial analysis, which showed that an earthy taste was the main problem with consumer satisfaction.

Oral antioxidant therapy for prevention and treatment of preeclampsia: Meta-analysis of randomized controlled trials.

AIMS: To determine whether oral antioxidant therapies, of various types and doses, are able to prevent or treat women with preeclampsia. DATA SYNTHESIS: The following databases were searched: MEDLINE, CENTRAL, LILACS, and Web of Science. Inclusion criteria were: a) randomized clinical trials; b) oral antioxidant supplementation; c) study in pregnant women; d) control group, treated or not with placebo. Papers were excluded if they evaluated antioxidant nutrient supplementation associated with other non-antioxidant therapies. Data were extracted and the risk of bias of each study was assessed. Heterogeneity was analyzed using the Cochran Q test, and I2 statistics and pre-specified sensitivity analyses were performed. Meta-analyses were conducted on prevention and treatment studies, separately. The primary outcome was the incidence of preeclampsia in prevention trials, and of perinatal death in treatment trials. Twenty-nine studies were included in the analysis, 19 for prevention and 10 for treatment. The antioxidants used in these studies were vitamins C and E, selenium, l-arginine, allicin, lycopene and coenzyme Q10, none of which showed beneficial effects on the prevention of preeclampsia (RR: 0.89, CI 95%: [0.79-1.02], P = 0.09; I2 = 39%, P = 0.04) and other outcomes. The antioxidants used in the treatment studies were vitamins C and E, N-acetylcysteine, l-arginine, and resveratrol. A beneficial effect was found in intrauterine growth restriction. CONCLUSIONS: Antioxidant therapy had no effects in the prevention of preeclampsia but did show beneficial effects in intrauterine growth restriction, when used in the treatment of this condition.

Developmental trajectories of children with Down syndrome by socio-economic status: the case of Latin America.

BACKGROUND: Several studies show that socio-economic status (SES) is related to the developmental trajectories of children with typical development (TD). However, few studies have analysed this relationship regarding children with neurodevelopmental disorders such as Down syndrome (DS). In this paper, we analyse the impact of SES in the neurodevelopmental trajectories of children with DS in comparison with children with TD. METHOD: Cognitive, language, motor and socio-emotional development were assessed in 31 children with DS between the ages of 15 and 80 months from high to low SES backgrounds. Data from this group were compared with data from a sample of 72 children with TD randomly selected from the Longitudinal Survey of Early Childhood. We analyse and compare these two groups using the developmental trajectories method RESULTS: The results show delayed onsets for the four abilities measured in children with DS compared with children with TD from high to low SES. In the comparison of the developmental trajectories, we found that the differences between the neurodevelopmental trajectories in DS and TD vary according to SES. High SES show differences only in language development, while low SES show significant differences in cognitive, language and socio-emotional development. CONCLUSIONS: The results indicate that SES is a factor that could impact the developmental trajectories of children with DS. Although the differences between children with DS and with TD are similar at the beginning regardless of SES, the developmental trajectories are slower in children with DS of low SES than in children of high SES. We argue that the differences are related to the complex interaction of several biological and cultural factors associated with SES. Some specific hypotheses about nutrition, health care access, quality of education and parenting practices are presented, but more research in this area is needed to fully understand these results.

The bone degenerative processes in senile fishes from Holocene Brazilian shell mounds.

Zooarchaeological collections from shell mounds in Rio de Janeiro (2,470-4,632 cal BP) contain a high prevalence of swollen fish bones belonging to the Atlantic spadefish (Chaetodipterus faber), crevalle jack (Caranx hippos) and fat snook (Centropomus parallelus). Given the lack of knowledge of the bone degenerative process in senile fishes, this study analysed hyperostotic bone in zooarchaeological and modern specimens to obtain high-resolution morphology and microstructure reconstruction. We used microCT as well as X-ray diffraction to characterize the crystallographic changes associated with fish senility. Our results showed that trabecular microstructures in hyperostotic bones were consistent with estimated values of the per cent bone volume-to-total volume ratio (BV/TV) and were greater than 60% in cortical bone. Hyperostotic bones indicated a high radiograph density, and X-ray diffractograms showed a decrease in hydroxyapatite [Ca10 (PO4 )6 (OH)2 ] and calcite (CaCO3 ) neocrystallization. These crystalline and density changes revealed an advanced stage of fish senile and indicate the vulnerability of ageing fish populations.

Sensory profile, soluble sugars, organic acids, and mineral content in milk- and soy-juice based beverages.

The juice industry has undergone a continuous innovation to satisfy the increasing healthy food demand by developing, among others, beverages based on fruits and milk or soybeans. The comparison among the sensory attributes between nineteen commercial mixed beverages showed significant differences in colour, sweetness, acidity, and consistency. Sucrose and citric acid were found in large proportion due to their natural presence or their addition. Potassium was the major macromineral (148-941 mg/L), especially in soy beverages. The low concentration of sodium in soy drinks is a healthy characteristic. The profile of inorganic anions has been included for the first time. Sulphate (39-278 mg/L) and phosphate (51-428 mg/L) were the predominant anions. High correlations were found between the percentage of fruit and consistency, fructose, malic acid, potassium and phosphate content (r(2)>0.790). Based on the data obtained, these beverages show pleasant organoleptic characteristics and constitute a good source of essential nutrients for regular consumers.

Molecular identification of trypanosomatids in wild animals.

Diverse wild animal species can be reservoirs of zoonotic flagellate parasites, which can cause pathologic Chagas disease. The present study aimed to detect the natural occurrence of flagellate parasites through direct microscopic examination of the parasites in blood samples and through PCR of whole blood and blood culture (haemoculture) samples from 38 captive and 65 free-living wild animals in the Centre for Conservation of Wild Fauna (CCWF), an area endemic for leishmaniasis. For this study, PCR was accomplished using primers for the ribosomal region (ITS-1) of the flagellate parasites. The amplified fragments were cloned and sequenced to identify DNA of the Trypanosomatid parasite species, observed in blood cultures from 3.9% (04/103) of the animals. Through these techniques, Trypanosoma cruzi was identified in haemoculture samples of the following three free-living species: common agouti (Dasyprocta aguti), white-eared opossum (Didelphis albiventris), and nine-banded armadillo (Dasypus novemcinctus). Furthermore, Trypanosoma minasense was identified in whole blood samples from 01 (0.9%) captive animal (black howler monkey-Alouatta caraya). These results demonstrated the first report of T. cruzi isolation in wild species from the CCWF using blood culture, which can be applied in addition to molecular tools for epidemiological studies and to identify trypanosomatids in wild animals.

Cytogenetics findings in a histiocytic sarcoma case.

Histiocytic sarcoma (HS) is a neoplasm derived from histiocytes. Its diagnosis was not clear until its immunohistochemistry profile was correctly established. Not much is known about its genetic properties. We report a case of a 48-year-old male patient whose bone marrow was almost completely occupied by monomorphic medium size neoplastic cellularity. Its immunohistochemical profile was CD68(+), CD4(+), CD45(+) with negativity of other dendritic cells, and other lineage markers. Cytogenetic study showed 4 related clones: one with trisomy 8 and extra material on the short arms of chromosome 4; a second line with tetrasomy of chromosome 8, add(4)(p16); the third clone had the same alterations as the previous and deletion of chromosome 3 at q11; the fourth line had tetrasomy 8 and translocation t(3;5)(q25;q35). To our knowledge this is the first HS case showing chromosome 8 trisomy and tetrasomy and the other described alterations.

Acute kidney injury as a risk factor for chronic kidney diseases in disadvantaged populations.

Acute kidney injury (AKI) is considered to be a potential cause for developing chronic kidney disease (CKD); on the other hand, CKD predisposes to AKI. The lack of adequate epidemiological data makes it difficult to determine if AKI induces CKD in less developed countries. The etiology of AKI in rich populations, in whom sophisticated surgery, interventional radiology and oncology treatments are usually the cause of AKI, is very different from that of disadvantaged populations, where the origin of AKI is associated with endemic infections, obstetric problems, poisons, toxins and natural disasters. Any conclusions extrapolated from these two settings should be treated with caution. Moreover, people living in disadvantaged conditions are usually much younger than those in rich areas and this age factor could facilitate total recovery of renal function after AKI if treatment based on an adequate supply of water, rehydration and anti-infectious measures were provided. In the small segment of the population of less developed countries having an income per capita similar to that observed in the developed countries, the long-term outcome of AKI should also be expected to be similar. New data coming from two single centers analyzing only the long-term outcome of acute tubular necrosis (ATN) patients, with a normal or near normal renal function prior to the AKI episode, coincide in reporting a requirement for chronic dialysis among the surviving patients of 2%. If these data are confirmed, the importance of AKI as cause of CKD should be reconsidered, both in developed and less developed countries.

Different flowering phenology of alien invasive species in Spain: Evidence for the use of an empty temporal niche?

Flowering phenology is an important and poorly understood plant trait that may possibly be related to the invasiveness potential of alien species. The present work evaluates whether flowering time of invasive alien species is a key trait to overcome the climatic filters operating in continental Mediterranean ecosystems of Spain (characterised by summer drought and low temperatures in winter). We conducted comparisons between the flowering phenology of the invasive species in their native range and in Spain, and between flowering phenology of 91 coexisting invasive-native species pairs. For the alien species, geographical change from the native to the invaded region did not result in shifts in the start and the length of the flowering period. Overall, climatic conditions in the native range of species selected for a flowering pattern is maintained after translocation of the species to another region. Flowering of tropical and temperate invasive alien species peaked in summer, which contrasts with the spring flowering of native and invasive alien species of Mediterranean climate origin. By exploiting this new temporal niche, these invasive alien species native to tropical and temperate regions benefit from reduced competition with natives for abiotic and biotic resources. We suggest that human-mediated actions have reduced the strength of the summer drought filter in particular microhabitats, permitting the invasion of many summer-flowering aliens.

Long-term outcome of acute tubular necrosis: a contribution to its natural history.

As long-term outcome studies of acute renal failure (ARF) are scarce and non-homogeneous, we studied 187 consecutive acute tubular necrosis (ATN) patients without previous nephropathies, discharged alive from our hospital between October 77 and December 92 and followed-up until December 99 (range 7-22 years; median 7.2). Variables were analyzed at the time of the acute episode and during follow-up. In 2000-2001 a clinical evaluation was made in 58 of the 82 patients still alive. Ten patients were lost to follow-up and 95 died. In 59% death was related with the disease present when the ATN developed. Kaplan-Meir survival curve showed 89, 67, 50, and 40% at 1, 5, 10, and 15 years, respectively, after discharge. Survival curves were significantly better (log-rank P<0.001) among the youngest, those surviving a polytrauma, those without comorbidity and surprisingly those treated in intensive care units. The proportional Cox model showed that age (hazard ratio (HR) 1.04 per year of age; P=0.000), presence of comorbid factors (HR 4.29; P=0.006), surgical admission (HR 0.45; P=0.000), and male sex (HR 1.72; P=0.020) were the variables associated with long-term follow-up. In the evaluated patients renal function was normal in 81%. Long-term outcome after ARF depends on absence of co-morbid factors, cause of initial admission and age. Although the late mortality rate is high and related with the original disease, renal function is adequate in most patients.

[Urea distribution volume calculated by ionic dialysance]. / Cálculo del volumen de distribución de la urea mediante dialisancia iónica.

BACKGROUND: Direct dialysis quantification is considered the gold standard for determining urea distribution volume, but it is impractical for routine use. So, urea distribution volume in hemodialysis patients is usually estimated from anthropometric equations. Ionic dialysance allows to calculate the urea distribution volume dividing the Kt obtained by ionic dialysance by the Kt/V obtained by a simplified formula. The aim of the present work was to analyse the concordance between the ionic dialysance and the direct dialysis quantification methods to estimate de urea distribution volume. MATERIAL AND METHODS: In 15 hemodialysis patients (10 males and 5 females), we have estimated the urea distribution volume by the direct dialysis quantification (Vurea), by the anthropometrics equations of Watson (VWatson) and Chertow (VChertow) and by the ionic dialysance method (VDI). To obtain VDI we have used two simplified Kt/V formulas: the monocompartimental and the equilibrated Daugirdas equations (VDIm and VDIe respectively). The intermethod variability was assessed by the relative difference (absolute difference between VUrea and the other methods, divided by the mean). RESULTS: VUrea (26,2 L) was statistically different from theVDIe (30,6 L, p < 0.01), VWatson 35.2 L (p < 0.001) and VChertow (38 L, p < 0.001). VDIm was 26.3 L (p = ns). VUrea represents the 42% of the body weight for the males (range 36 to 49%) and the 33% of the body weight for the female (range 28 to 38%). The intermethod variability was high for the VDIe (21.6%), VWatson (37.4%) and VChertow (48. 1%), but it was low for the VDIm (9.9%). CONCLUSIONS: Urea distribution volume calculated by the ionic dialysance method using the monocompartimental Daugirdas Kt/V equation has an acceptable agreement with the urea distribution volume calculated by the direct dialysis quantification. Anthropometry-based equations overestimate the urea distribution volume in hemodialysis patients.

Cálculo del volumen de distribución de la urea mediante dialisancia iónica / Urea distribution volume calculated by ionic dialysance

Introducción: En la práctica clínical el volumen de distribución de la urea sesuele calcular por fórmulas antropométricas, pero el método más seguro es mediantela cuantificación de la urea eliminada en la sesión de diálisis, lo que implicala recogida del dializado y la determinación de la concentración plasmáticade urea tras haberse alcanzado el equilibrio postdiálisis. La dialisancia iónica permitecalcular el volumen de distribución de la urea dividiendo el Kt obtenido pordialisancia iónica por el Kt/V proporcionado por las fórmulas simplificadas.El objetivo del presente trabajo ha consistido en estudiar la concordancia entrelos diversos métodos para calcular el volumen de distribución de la urea.Material y métodos: En 15 enfermos (10 varones y 5 mujeres) hemos calculadoel volumen de distribución de la urea mediante la cuantificación de la ureaeliminada (VUrea) y lo hemos comparado con el obtenido por dos fórmulas antropométricas(Watson y Chertow) y por la dialisancia iónica (VDI). Para obtenerel VDI se utilizaron las ecuaciones de Daugirdas para los modelos monocompartimentaly equilibrado. Se consideraron pues dos VDI (VDIm y VDIe respectivamente)según la ecuación de Daugirdas empleada. Para estudiar la concordanciahemos utilizado la diferencia relativa (diferencia absoluta entre cada método y elVUrea dividido por la media aritmética).Resultados: El VUrea fue de 26,2 L que representa el 42% del peso en varones(con un amplio rango entre 36 y 49%) y un 33% en mujeres (rango 28-38%). El volumen de distribución de la urea con los otros métodos fue: Watson35,2 L (p < 0,001), Chertow 38 L (p < 0,001), VDIe 30,6 L (p < 0,01) y VDIm26,3 L (p = ns). La diferencia relativa del VUrea con las fórmulas antropométricasy con el VDIe fue muy alta (Watson: 37,4%, Chertow: 48,1%, VDIe 21,6%),obteniéndose una concordancia aceptable con el VDIm (9,9%).Conclusiones: El volumen de distribución de la urea calculado por dialisanciaiónica y la ecuación de Kt/V monocompartimental de Daugirdas, tiene una concordanciaclínicamente aceptable con el obtenido mediante la recogida del dializado.Los métodos antropométricos proporcionan unos valores mucho más elevados,con diferencias que son inaceptables desde el punto de vista clínico

Background: Direct dialysis quantification is considered the gold standard fordetermining urea distribution volume, but it is impractical for routine use. So, ureadistribution volume in hemodialysis patients is usually estimated from anthropometricequations. Ionic dialysance allows to calculate the urea distribution volumedividing the Kt obtained by ionic dialysance by the Kt/V obtained by a simplifiedformula. The aim of the present work was to analyse the concordancebetween the ionic dialysance and the direct dialysis quantification methods to estimatede urea distribution volume.Material and methods: In 15 hemodialysis patients (10 males and 5 females),we have estimated the urea distribution volume by the direct dialysis quantification(Vurea), by the anthropometrics equations of Watson (VWatson) and Chertow(VChertow) and by the ionic dialysance method (VDI). To obtain VDI wehave used two simplified Kt/V formulas: the monocompartimental and the equilibratedDaugirdas equations (VDIm and VDIe respectively). The intermethod variabilitywas assessed by the relative difference (absolute difference between VUreaand the other methods, divided by the mean).Results: VUrea (26,2 L) was statistically different from theVDIe (30,6 L, p <0.01), VWatson 35.2 L (p < 0.001) and VChertow (38 L, p < 0.001). VDIm was26.3 L (p = ns). VUrea represents the 42% of the body weight for the males(range 36 to 49%) and the 33% of the body weight for the female (range 28 to38%). The intermethod variability was high for the VDIe (21.6%), VWatson(37.4%) and VChertow (48.1%), but it was low for the VDIm (9.9%).Conclusions: Urea distribution volume calculated by the ionic dialysance methodusing the monocompartimental Daugirdas Kt/V equation has an acceptableagreement with the urea distribution volume calculated by the direct dialysis quantification.Anthropometry-based equations overestimate the urea distribution volumein hemodialysis patients

Lumbar bone mineral density after kidney transplantation: a three-year prospective study.

Osteopenia is a common complication after transplantation. However, prospective long-term studies are scarce and most were performed in patients on cyclosporine and high-dose steroids. In 65 patients with functioning grafts, 41 males and 24 females, 50 on tacrolimus-based immunosuppression and 15 on cyclosporine-based immunosuppression, bone mineral density (BMD) was measured in the lumbar spine (L2-L4) and femoral neck (FN) using dual X-ray absorptiometry (DEXA) in the first month after transplantation (baseline) and at 1, 2, and 3 years. At baseline, BMD was similar to the control population both in L2-L4 (z score = -0.421) and in FN (z score = -0.518). During the follow-up, 3 types of patterns were identified: BMD increased in L2-L4 in 25 patients (38.5%), remained stable in 20 patients (30.8%), and decreased in 20 patients (30.8%). BMD losses appeared mainly during the first year (0.964 +/- 0.162 baseline; 0.904 +/- 0.161 at 1 year, 0.886 +/- 0.140 at 3 years; analysis of variance [ANOVA] P < .001). However, the improvement was maintained throughout the follow-up (0.860 +/- 0.176 g/cm2 at baseline; 0.901 +/- 0.161 at 1 year; 0.954 +/- 0.178 at 3 years; ANOVA P < .001) and there was a parallel increase of BMD in FN (0.712 +/- 0.144 at baseline; 0.744 +/- 0.249 at 1 year; 0.826 +/- 0.184 at 3 years; ANOVA P < .01). There were no differences between both groups in graft function, intact parathyroid hormone (iPTH) levels, number of postmenopausal women, or steroid doses. About one third of patients had bone loss during the first year after transplantation. We were unable to identify any risk factor for this complication in patients on low-dose steroids.