A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Alterações metabólicas e morfométricas induzidas por hipóxia em Gallus gallus

Low O2 partial pressure during embryonic and fetal development can decrease the growth and metabolic rate of the embryo, leading to morphophysiological changes after birth, and blunt the hypoxic ventilatory response in newly hatched chicken. In the present study, different conditions during incubation (cold and hypoxia) were performed to evaluate the effect of prenatal hypoxia on metabolic rate, and the response to acute hypoxia in different strains and ages of Gallus gallus. We also considered the possibility that prolonged metabolic depression per se, but not specifically induced by hypoxia, during incubation would be a contributing factor to decreased metabolic rate in neonate. Thus chicken embryos were incubated at 35◦C (cold group), which is known to decrease the embryonic oxygen consumption (VO2) by ~ 30% throughout the incubation period and increases the incubation time in ~2 days. Finally, in precocial birds, no study has approached the influence of hypoxia at different stages of incubation in the morphometric development of the intestine, not only important for the digestive processes and absorption, but also for protection against pathogens, so we evaluated the morphometric characteristics and quantity of goblet cells per villi of the small intestine regions in newly hatched broiler chicksBaixa pressão parcial de O2 durante o desenvolvimento embrionário e/ou fetal pode diminuir a taxa metabólica e a taxa de crescimento do embrião, podendo levar a alterações morfofisiológicas após o nascimento, além de atenuar a resposta ventilatória hipóxica no recém-eclodido de galinhas. No presente estudo, várias incubações foram realizadas para avaliar o efeito da hipóxia pre-natal sobre a taxa metabólica e a resposta à hipóxia aguda em diferentes linhagens e idades de Gallus gallus. Além disso, foi verificada a possibilidade de que a redução da taxa metabólica por si e não especificamente induzida por hipóxia prolongada durante desenvolvimento pré-natal seria um fator contribuinte sobre a diminuição da taxa metabólica em neonatos. Para isso embriões de galinha foram incubados a 35 ◦C (grupo de frio), que é conhecido por diminuir o consumo de oxigênio embrionário por ~30% ao longo de incubação, e aumenta o período de incubação em ~2 dias. Quanto a aves precoces, nenhum estudo havia abordado a influência da hipóxia em diferentes fases de incubação no desenvolvimento morfométrico do intestino, importante não somente para os processos digestivos e de absorção, mas também para a proteção contra patógenos; por isto avaliamos as características morfométricas e a quantidade de células caliciformes por vilo das regiões do intestino delgado em pintainhos recémeclodidos de frango de cort

Thermogenesis, vocalization, and temperature preference of 1-day-old chicken hatchlings after cold-exposure in late embryogenesis

In a thermal gradient the preferred ambient temperature (T (a) pref) of chicken hatchlings is a few degrees lower than thermoneutrality. To investigate whether a correlation may exist between T (a) pref and the autonomic thermogenic capacity or not we studied a group of hatchlings (N = 15) exposed to cold at end-incubation, a procedure known to increase their postnatal thermogenesis. Chicken embryos were exposed to cold (34.5 A degrees C instead of 38 A degrees C) at days 18-20 of incubation. By comparison to Controls (N = 15), they hatched a few hours later, with similar body weight, body temperature, vocalization (number of sounds produced per unit time), and oxygen consumption (, measured in a respirometer by an open-flow methodology). When exposed to slow cooling these hatchlings had a higher lower critical temperature (LCT) of thermoneutrality and higher , and slightly higher vocalization than Controls. In a thermal gradient, T (a) pref averaged 34.3 +/- A 0.3 A degrees C, or 1 A degrees C higher than in Controls (33.4 +/- A 0.3 A degrees C; P < 0.05), in proportion with their higher LCT (38 +/- A 0.1 A degrees C instead of 36.7 +/- A 0.3 A degrees C; P < 0.001), so that the T (a) pref - LCT difference (-3.6 +/- A 0.3 A degrees C) was similar to Controls (-3.3 +/- A 0.3 A degrees C). In conclusion, in chicken hatchlings T (a) pref was lower than LCT irrespective of the magnitude of their thermogenic response. It was estimated that, at T (a) pref, was similar to 20 % higher than at thermoneutrality. Such metabolic increase could carry some physiological advantage and the choice of T (a) pref may reflect the hatchling's needs to maintain slightly elevated.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Chicken hatchlings prefer ambient temperatures lower than their thermoneutral zone

We investigated whether or not the preferred ambient temperature (Tapref) of the 1-day old chicken hatchling, a precocial neonate with excellent locomotory capacity, clearly identifiable thermogenesis and independence from maternal care, coincides with the lower critical temperature (LCT) of thermoneutrality and minimal oxygen consumption ((V) over dot(O2)). Tapref of single chicks measured in a thermocline (N = 16) averaged 33.5 +/- 0.3 degrees C (mode, 33.3 +/- 0.4 degrees C). The same value was obtained in hatchlings studied in pairs. LCT was computed from the ambient temperature (Ta)-(V) over dot(O2) relationship, constructed by slowly decreasing the Ta of a respirometer from 38 to 29 degrees C over 2.5 h, while continuously measuring (V) over dot(O2) by an open-flow methodology; LCT averaged 36.4 degrees C +/- 0.3 or 36.8 degrees C +/- 0.4, depending on the method of computation. In all hatchlings Tapref was lower than LCT (P < 0.001), by a magnitude that depended on the method of computation of the two variables, 2.8 degrees C +/- 0.3 (P < 0.001) or 3.9 degrees C +/- 0.5. The Tapref-LCT difference implied that, at Tapref, (V) over dot(O2) was higher than at thermoneutrality. We conclude that in the chicken hatchling thermal preference does not coincide with thermoneutrality, probably because during development what seems optimal from a thermoregulatory viewpoint may not necessarily be so for other regulatory functions. (C) 2014 Elsevier Inc All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP