Hipopituitarismo. Una causa poco frecuente de retraso psicomotor

Sr. Editor: El hipopituitarismo es un síndrome clínico, resultante de la secreción insuficiente o ausencia completa de secreción de una o varias hormonas hipofisarias anteriores. Aunque típicamente el diagnóstico se suele realizar en período neonatal, en ocasiones, su primera manifestación puede ser un retraso psicomotor en loa lactantes, por lo que el diagnóstico precoz puede prevenir el deterioro neurocognitivo, evitando la aparición de secuelas neurológicas. Se presentan 2 casos de hipopituitarismo, diagnosticados a raíz de la presencia de retraso psicomotor en periodo de lactante: Caso 1 Recién nacida mujer a término, controlada por aumento craneal del diámetro biparietal y ventriculomegalia de ventrículos laterales con colpocefalia, sin signos de hipertensión intracraneal. Con 20 meses persiste ausencia de bipedestación y lenguaje; estudio analítico neurometabólico, carga viral de citomegalovirus, electroencefalograma, potenciales evocados auditivos, fondo de ojo, cariotipo y cribado neonatal normal. A los 21 meses presenta longitud de 70, 3 cm (–4, 8 DE) y peso de 6, 9 kg (–3, 71 DE), baja velocidad de crecimiento y estudio analítico hormonal compatible con déficit de hormona de crecimiento (GH), con el resto de estudios, incluido el tiroideo, normal. En el estudio genético arrays-CGH se detecta una deleción 1q25.2, asociado a haploinsuficiencia del gen LHX4..

Hypothalamyc hamartomas: Different ways of clinical debut. Cases report

Los hamartomas hipotalámicos son malformaciones no neoplásicas de sustancia gris compuestas por neuronas hiperplásicas. Suelen ser lesiones pequeñas localizadas en la base del cerebro, en el piso del tercer ventrículo y, generalmente, asintomáticas. Sin embargo, pueden ocurrir con alteraciones conductuales-cognitivas, crisis epilépticas y/o signos de pubertad precoz central en función de la localización en la que se encuentren. Se presentan dos pacientes de 2 años 8 meses y 7 años, con presencia de hamartomas hipotalámicos diagnosticados tras el estudio de pubertad precoz central. La paciente de menor edad presenta, además, crisis gelásticas, típicamente asociadas a hamartomas hipotalámicos. Tras los hallazgos clínicos y radiológicos, se trataron con análogos de gonadotropinas, y se observó una regresión de los signos puberales y una no progresión del tamaño de los hamartomas. Hypothalamic hamartomas are benign tumors of gray substance composed by hyperplasic neurons. They are usually asymptomatic small masses with extensions into the third ventricular cavity. In some instances they can cause cognitive behavioral alterations, seizures and/or central precocious puberty depending on the location. Here we present two cases of central precocious puberty due to hypothalamic hamartomas at 28/12 and 7 years of age. The younger patient also presents gelastic seizures, typically associated with hypothalamic hamartomas. After the clinical and radiological findings, they started treatment with GnRH analogues and a regression of the puberty signs without progression in the hamartomas size was observed

Application of a triple ¹⁵N tracing technique to elucidate N transformations in a UK grassland soil

To identify the production and consumption pathways and temporal dynamics of N2O emitted from soil, this study uses 15N-labelled substrate-N to quantify the underlying gross N transformation rates using the Ntrace analysis tool and link them to N-emissions. In three experiments twelve soil cores each were incubated in a lab incubation system to measure gaseous emissions, while parallel incubations under the same conditions were set up for destructive soil sampling at 7 time points. Using the triple labelling technique (applying NH4NO3 with either the NH4+-N or the NO3−-N, or both being 15N labelled), this study investigated the effects of 55, 70 and 85% water filled pore space (deemed to promote nitrification, both nitrification and denitrification, and denitrification, respectively) in a clay soil on gaseous N emissions and investigates the source and processes leading to N2O emissions. To assess the utilisation of applied NO3− vs. nitrified NO3− from applied NH4+, the 15N tracing tool Ntrace was used to quantify the rates of immobilisation of NO3− and NH4+, oxidation of NH4+, mineralisation of organic N and subsequent nitrification by the analysis of the 15N in the soil. Gross transformation rates were calculated, indicating the relative importance of added NO3− and NO3− derived from nitrified added NH4+. Results show an important contribution of heterotrophic nitrification (organic N oxidation to NO3−) which was highest at the 55% water filled pore space (WFPS), decreasing in its contribution to N-transformation processes with increasing WFPS, while nitrification (NH4+ oxidation to NO3−) was contributing the most at 70% WFPS. The contribution of denitrification increased with increasing WFPS, but only became dominant at 85% WFPS. While denitrification still showed to be most important at high and nitrification at lower WFPS, the actual % WFPS values were not as expected and highlight the fact that WFPS is a contributor, but not the sole/most important parameter determining the type of N-transformation processes taking place

Meta-analysis of global livestock urine-derived nitrous oxide emissions from agricultural soils.

Abstract:Nitrous oxide (N2O) is an air pollutant of major environmental concern, with agriculture representing 60% of anthropogenic global N2O emissions. Much of the N2O emissions from livestock production systems result from transformation of N deposited to soil within animal excreta. There exists a substantial body of literature on urine patch N2O dynamics, we aimed to identify key controlling factors influencing N2O emissions and to aid understanding of knowledge gaps to improve GHG reporting and prioritize future research. We conducted an extensive literature review and random effect meta?analysis (using REML) of results to identify key relationships between multiple potential independent factors and global N2O emissions factors (EFs) from urine patches. Mean air temperature, soil pH and ruminant animal species (sheep or cow) were significant factors influencing the EFs reviewed. However, several factors that are known to influence N2O emissions, such as animal diet and urine composition, could not be considered due to the lack of reported data. The review highlighted a widespread tendency for inadequate metadata and uncertainty reporting in the published studies, as well as the limited geographical extent of investigations, which are more often conducted in temperate regions thus far. Therefore, here we give recommendations for factors that are likely to affect the EFs and should be included in all future studies, these include the following: soil pH and texture; experimental set?up; direct measurement of soil moisture and temperature during the study period; amount and composition of urine applied; animal type and diet; N2O emissions with a measure of uncertainty; data from a control with zero?N application and meteorological data

Soil nitrous oxide emissions from grassland: Potential inhibitor effect of hippuric acid

In grassland systems, cattle and sheep urine patches are recognized as nitrous oxide (N₂O) emission hot spots due to the high urinary nitrogen (N) concentrations. Hippuric acid (HA) is one of the constituents of ruminant urine that has been reported as a natural inhibitor of soil N₂O emissions. The aim of this study was to examine the potential for elevated ruminant urine HA concentrations to reduce N₂O emissions, in situ, on an acidic heavy clay soil under poorly drained conditions (WFPS > 85%). A randomized complete block design experiment with three replications and four treatments was conducted using the closed-static-flux chamber methodology. The four treatments were applied inside the chambers: control with no artificial urine application (C), control artificial urine (U), and enriched artificial urine with two rates of HA (55.8 and 90 mM, U+HA1, U+HA2). Soil inorganic-N, soil dissolved organic carbon (DOC), soil pH as well as N₂O and methane (CH₄ ) fluxes were monitored over a 79-d period. Although N₂O emissions were not affected by the HA enriched urine treatments, U+HA2 positively affected the retention of N as NH⁺₄ until day 3, when the soil pH dropped to values < 5. Subsequently, as a consequence of rainfall events and soil acidification, it is likely that leaching or sorption onto clay reduced the efficacy of HA, masking any treatment differential effect on N₂O emissions. Moreover, CH₄ fluxes as well as DOC results reflected the soil anaerobic conditions which did not favour nitrification processes. Further research is needed to determine the fate of HA into the soil which might clarify the lack of an in situ effect of this compound

Sheep urination frequency, volume, N excretion and chemical composition: Implications for subsequent agricultural N losses

Ruminant urine patches are potential sites of reactive nitrogen (N) loss to the environment. Quantification of N losses from grazed grasslands requires measurement of the frequency of urine deposition, as well as its volume and chemical composition. However, studies to date are typically restricted to analyses of few replicate animals and urination events, especially for sheep. Here, we present data on urine frequency, volume, chemical composition (n=193 events from n=6 sheep) and metabolomic profile (n=4–5 events from n=4–5 sheep) from penned sheep. Differences in urine parameters and chemical composition data were compared seasonally and between two sites (improved and semi-improved pasture). Sheep urinated 8–11 times d−1, assuming time within pens represented a 24 h period. The mean urine event volume recorded was 289±14 mL, from which we estimated a daily urine production value of 2.77±0.15 L urine sheep−1 d−1. Daily urine N excretion and individual urine N concentrations were greater from sheep in improved pasture (26.7±2.3 g N sheep−1 d−1; 7.0±0.2 g N L−1) compared to those in semi-improved pasture (16.7±1.2 g N sheep−1 d−1; 5.5±0.4 g N L−1), but this did not equate to greater individual urine patch N loadings due to site differences in the urine-tosoil surface area influenced (17.5 L m-2 at the semi-improved site and 8.9 L m-2 at the improved site). Urine chemical composition varied seasonally and by site. Site- and season-specific urine should, therefore, be used in studies assessing N losses from urine patches. Based on the urine chemical composition data, we provide an updated artificial sheep urine ‘recipe’ which could be utilised to replicate natural sheep urine. The urine metabolomic profile clustered according to pasture quality, while clustering according to season was less evident. Our results provide important information for experimental and modelling studies assessing the scale and nature of N pollution arising from sheep-grazed pastures