Lactation attenuates pro-oxidant reactions in the maternal brain.

Reactive oxygen species (ROS) are intimately linked to bioenergetics and redox biology, contributing to cellular functioning and physiological signaling, but also acting as toxic agents during oxidative stress. Hence, the balance between pro-oxidant reactions and the activity of antioxidant defenses sustains a basal oxidative status, controls the increase of redox signaling, and mediates potential pathological events during oxidative stress. Maternal experience, especially during nursing, requires high energetic demands and expenditure to ensure the well-being of the offspring. The mother must adapt from satisfying her own needs to additionally fulfilling those of her descendants. Oxidative stress has been proposed as one of the reproductive trade-off hallmarks. However, the oxidative shielding hypothesis has also been proposed in the context of reproduction. The reproductive experience induces a wide range of well-documented changes in the female brain, which potentially lead to protection against the enhanced oxidative activity. To date, the metabolic and cellular mechanisms that underlie lactation-induced neuroprotection against oxidants are unknown. The neuroendocrine changes in the brain of the lactating dam promote diminished propensity to excitotoxic brain injury and stress, as well as enhanced neuroprotection and plasticity. In addition to review studies on the oxidant balance due to motherhood, we included new data from our laboratory, addressing the importance of measuring pro-oxidant reactions in separated brain regions. The hippocampus of lactating rats exhibits lower levels of pro-oxidant reactions than that of virgin rats, supporting the oxidative shielding hypothesis in lactation.

Corrigendum: On the Basis of Synaptic Integration Constancy during Growth of a Neuronal Circuit.

[This corrects the article on p. 198 in vol. 10, PMID: 27587998.].

On the Basis of Synaptic Integration Constancy during Growth of a Neuronal Circuit.

We studied how a neuronal circuit composed of two neuron types connected by chemical and electrical synapses maintains constant its integrative capacities as neurons grow. For this we combined electrophysiological experiments with mathematical modeling in pairs of electrically-coupled Retzius neurons from postnatal to adult leeches. The electrically-coupled dendrites of both Retzius neurons receive a common chemical input, which produces excitatory postsynaptic potentials (EPSPs) with varying amplitudes. Each EPSP spreads to the soma, but also crosses the electrical synapse to arrive at the soma of the coupled neuron. The leak of synaptic current across the electrical synapse reduces the amplitude of the EPSPs in proportion to the coupling ratio. In addition, summation of EPSPs generated in both neurons generates the baseline action potentials of these serotonergic neurons. To study how integration is adjusted as neurons grow, we first studied the characteristics of the chemical and electrical connections onto the coupled dendrites of neuron pairs with soma diameters ranging from 21 to 75 µm. Then by feeding a mathematical model with the neuronal voltage responses to pseudorandom noise currents we obtained the values of the coupling ratio, the membrane resistance of the soma (rm ) and dendrites (r dend), the space constant (λ) and the characteristic dendritic length (L = l/λ). We found that the EPSPs recorded from the somata were similar regardless on the neuron size. However, the amplitude of the EPSPs and the firing frequency of the neurons were inversely proportional to the coupling ratio of the neuron pair, which also was independent from the neuronal size. This data indicated that the integrative constancy relied on the passive membrane properties. We show that the growth of Retzius neurons was compensated by increasing the membrane resistance of the dendrites and therefore the λ value. By solely increasing the dendrite resistance this circuit maintains constant its integrative capacities as its neurons grow.

Impacto de tres años de experiencia en tromboendarterectomía pulmonar / Three-year impact of experience with pulmonary thromboendarterectomy

Objetivo: Describir la experiencia clínica de una serie de casos de pacientes adultos con hipertensión pulmonar tromboembólica crónica, llevados a tromboendarterectomía pulmonar. Métodos: Estudio descriptivo, retrospectivo, de ocho pacientes adultos llevados a tromboendarterectomía pulmonar en la Fundación Cardiovascular de Colombia, entre febrero de 2010 y abril de 2013. Resultados: se evaluaron 5 mujeres y 3 hombres, con promedio de edad 45 ± 18 años, datos basales promedio de SpO2 92 ± 2%, PaO2/FiO2 244 ± 82, PaCO2 28,8 ± 3,4 mm Hg, presión pulmonar media 53 ± 11 mm Hg y resistencia vascular pulmonar (RVP) 999 ± 414 dyn/s/cm−5. Al tercer día postoperatorio un paciente necesitó oxigenación con membrana extracorpórea (ECMO) venoarterial por 11 días. A los 4 ± 1días de tromboendarterectomía pulmonar, la RVP descendió 71 ± 21% respecto al valor basal (p = 0,002, IC 95%) y la presión pulmonar media disminuyó 32 ± 27 mm Hg (p = 0,001). La SpO2 basal aumentó 96 ± 3%. La sobrevida fue del 100% a los 24 meses de seguimiento, sin reingresos ni recurrencia de tromboembolia pulmonar. Conclusiones: Los resultados institucionales fueron adecuados a corto y mediano plazo. En casos de edema por reperfusión la alternativa de ECMO como soporte vital extracorpóreo es indispensable.

Motivation: To describe clinical experience of a series of cases of adult patients with chronic thromboembolic pulmonary hypertension who underwent pulmonary thromboendarterectomy. Methods: Descriptive retrospective study of eight adults who underwent pulmonary thromboendarterectomy at the Fundación Cardiovascular de Colombia between February 2010 and April 2013. Results:5 women and 3 men were assessed, with an average age of 45 ± 18 years, with avergae baseline data of SpO2 92 ± 2%, PaO2/FiO2 244 ± 82, PaCO2 28.8 ± 3.4 mmHg, average pukmonary pressure of 53 ± 11 mmHg and pulmonary vascular resistance (PVR) of 999 ± 414 dyn/s/cm−5. On the third postoperative day one patient required veno-arterial extracorporeal membrane oxygenation (ECMO) during 11 days. At 4 ± 1 days after pulmonary thromboendarterectomy, PVR decreased 71 ± 21% with regards to baseline value (p = 0.002, IC 95%) and pulmonary pressure was reduced to 32 ± 27 mmHg (p = 0.001). Baseline SpO2 increased 96 ± 3%. Survival rate was 100% after 24 months of follow-up, without readmissions or recurrence of pulmonary thromboembolism. Conclusions: Institutional results were adequate in the short and medium term. Cases with reperfusion edema, the alternative of ECMO as an extracorporeal life support is imperative.

Efecto del Grupo Racial y Algunos Factores no Genéticos sobre la Producción de Leche e Intervalo entre Partos en Vacas de Doble Propósito / Effect of Breed Group and Some Non-genetic Factors on Milk Production and Calving Interval in Dual Purpose Cows

Para determinar el efecto del grupo racial y algunos factores no genéticos sobre la producción de leche corregida a 244 días (P244) y el intervalo entre parto (IEP), se analizaron 9469 y 6288 observaciones, respectivamente. Los animales se encontraban a pastoreo y en dos ordeños diarios. El modelo estadístico incluyó los efectos: finca (F:1, 2), año de parto (AP: 1995-2005) para P244 y (AP: 1995-2004) para IEP; mes de parto (MP:1,2,3,……,12), número de lactancia, (NL:1,…, 6 ó más), grupo racial ≥ ¾ Bos indicus, ≥ ¾ Bos taurus, 50%Holstein-50% Cebú, 50% Pardo Suizo-50% Cebú y Mosaico lechero, (GR:>CEBU, >E, H50CB50, PS50CB50, ML) y las interacciones FxAP, FxGR, FxNL, APxMP, APxNL. Todos los efectos afectaron a P244d e IEP, a excepción del mes de parto que no fue significativo para P244. La P244 e IEP promedio fueron de 1744 kg y 467 d, respectivamente. Las diferencias entre el mejor y el peor año en P244 e IEP fueron de 275 kg y 141 d, respectivamente. El GR con mayor producción de leche y con el mayor IEP fue PS50CB50 con 1844 kg y 487 d, respectivamente y el de menor producción y menor IEP fue>CEBU con 1619 kg y 452 d. La diferencia en P244 y IEP entre la primera y la quinta lactancia fue de 181 kg y 20 d, respectivamente. Existieron diferencias entre las dos haciendas de 84 kg y 22 d para P244d e IEP, respectivamente. Es interesante resaltar que la interacción FxGR fue significativa (P<0.01), indicando que los GR se comportan de forma diferente en cada finca. Se puede concluir que los efectos no genéticos y el GR tienen una alta influencia sobre la P244 y el IEP.

In order to establish the effect of breed group and some non-genetic factors on milk production corrected at 244 days (P244) and also on calving interval (IEP), 9469 and 6288, observations were analyzed, respectively. The animals were at grazing and milked twice daily. The statistical model included effects of: farm (F: 1,2); year of birth (AP:1995-2005) for P244, and (AP: 1995-2004) for IEP; month of birth (MP: 1, … 12), lactation number, (NL: 1...6 or more), breed group: mostly cebu (≥ ¾ Bos indicus); mostly European (≥ ¾ Bos taurus); 50% Holstein-50% Zebu; 50% Brown Swiss-50% Cebu and Dairy Crossbred Mosaic (GR:>CEBU, >E, H50CB50, PS50CB50, ML) and the interactions FxAP, FxGR, FxNL, APxMP, APxNL. All studied factor affected P244d and IEP, except the month of birth which, was not significant for P244. The average P244 and IEP were 1744 kg and 466 d, respectively. The differences between the best and worst year for P244 and IEP were 275 kg and 141 d, respectively. The GR with the higher milk production and highest IEP was PS50CB50 with 1844 kg and 487 d, respectively. As well, GR with the lower production and lowest IEP was > CEBUE with 1619 kg and 452 d, respectively. The difference for P244 and IEP between the first and fifth sixth lactation was 181 kg and 20 d, respectively. There was difference between the two farms of 84 kg and 22 d for P244d and IEP, respectively. It is interesting to note that FxGR interaction was significant (P<0.01), indicating that GR performed differently on each farm. It can be concluded that the non-genetic effects and GR have a high influence on the P244 and IEP.

Causas de salida en hembras brahman localizadas en zona de sabanas bien drenadas / Loss causes in brahman females located in well drained savannas

Se analizaron 497 registros de un rebaño de hembras Brahman, perteneciente a un hato ubicado en zona de sabanas bien drenadas del estado Guárico, Venezuela, con el objetivo de determinar las causas de salida. El análisis de los registros se realizó a través de la prueba de Bicuadrado. Se determinaron como causas de salida las ventas para matadero, ventas para cría, autoconsumo, desconocidas y mortalidad, siendo ésta última la principal causa de salida, responsable del 48,5% del total. La frecuencia de las diferentes causas de salida varió entre los diferentes años evaluados. Se concluyó que la alta proporción de salidas por muertes es reflejo de la problemática existentes en la zona (salud y nutrición animal), así como problemas asociados con el manejo.