Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas
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Braz. J. Med. Biol. Res. · Sep 2009
High mobility group box 1 as a mediator of endotoxin administration after hemorrhagic shock-primed lung injury.
High mobility group box 1 (HMGB1) was discovered as a novel late-acting cytokine that contributes to acute lung injury (ALI). However, the contribution of HMGB1 to two-hit-induced ALI has not been investigated. To examine the participation of HMGB1 in the pathogenesis of ALI caused by the two-hit hypothesis, endotoxin was injected intratracheally in a hemorrhagic shock-primed ALI mouse model. ⋯ Lung leak was also markedly reduced at 16 h; blockade of HMGB1 24 h after lipopolysaccharide injection failed to alter lung leak or myeloperoxidase at 48 h. Our observations suggest that HMGB1 plays a key role as a late mediator when lipopolysaccharide is injected after hemorrhagic shock-primed ALI and the kinetics of its release differs from that of one-hit ALI. The therapeutic window to suppress HMGB1 activity should not be delayed to 24 h after the disease onset.
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Braz. J. Med. Biol. Res. · Sep 2009
Randomized Controlled TrialThe effect of epidural and general anesthesia on newborn rectal temperature at elective cesarean section.
Both epidural and general anesthesia can impair thermoregulatory mechanisms during surgery. However, there is lack of information about the effects of different methods of anesthesia on newborn temperature. The purpose of this study was to determine whether there are differences in newborn rectal temperature related to type of anesthesia. ⋯ In contrast, newborn rectal temperatures were lower in the epidural anesthesia group than in the general anesthesia group (37.4 +/- 0.3 vs 37.6 +/- 0.3 degrees C; P < 0.05) immediately after birth. Furthermore, the umbilical vein pH value (7.31 +/- 0.05 vs 7.33 +/- 0.01; P < 0.05) and Apgar scores at the 1st-min measurement (8.0 +/- 0.9 vs 8.5 +/- 0.7; P < 0.05) were lower in the epidural anesthesia group than in the general anesthesia group. Since epidural anesthesia requires more iv fluid infusion and a longer time for cesarean section, it involves a risk of a mild temperature reduction for the baby which, however, did not reach the limits of hypothermia.
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Braz. J. Med. Biol. Res. · Aug 2009
Variable positive end-expiratory pressure can maintain oxygenation in experimental acute respiratory distress syndrome induced by oleic acid in dogs.
The use of positive end-expiratory pressure (PEEP) or lung recruitment maneuvers (RM) to improve oxygenation in acute respiratory distress syndrome (ARDS) is used but it may reduce cardiac output (CO). Intermittent PEEP may avoid these complications. Our objective was to determine if variable PEEP compared with constant PEEP is capable of maintaining arterial oxygenation and minimizing hemodynamic alterations with or without RM. ⋯ There was a reduction in CO in group 3 after RM (3.9 +/- 1.1 before to 2.7 +/- 0.5 L*min(-1)*(m(2))(-1) after; P < 0.05), but there was not any difference between constant and variable PEEP periods (2.7 +/- 0.5 and 2.4 +/- 0.7 L*min(-1)*(m(2))(-1); P > 0.05. Variable PEEP is able to maintain PaO(2) when performed in combination with RM in dogs with ARDS. After RM, CO was reduced and there was no relevant difference between the variable and constant PEEP periods.
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Braz. J. Med. Biol. Res. · Feb 2009
Pharmacological effects and behavioral interventions on memory consolidation and reconsolidation.
In this article, we will review some behavioral, pharmacological and neurochemical studies from our laboratory on mice, which might contribute to our understanding of the complex processes of memory consolidation and reconsolidation. We discuss the post-training (memory consolidation) and post-reactivation (memory reconsolidation) effects of icv infusions of hemicholinium, a central inhibitor of acetylcholine synthesis, of intraperitoneal administration of L-NAME, a non-specific inhibitor of nitric oxide synthase, of intrahippocampal injections of an inhibitor of the transcription factor NF-kappaB, and the exposure of mice to a new learning situation on retention performance of an inhibitory avoidance response. All treatments impair long-term memory consolidation and retrieval-induced memory processes different from extinction, probably in accordance with the 'reconsolidation hypothesis'.
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Braz. J. Med. Biol. Res. · Oct 2008
Randomized Controlled TrialEffect of melatonin administration on subjective sleep quality in chronic obstructive pulmonary disease.
Disturbed sleep is common in chronic obstructive pulmonary disease (COPD). Conventional hypnotics worsen nocturnal hypoxemia and, in severe cases, can lead to respiratory failure. Exogenous melatonin has somnogenic properties in normal subjects and can improve sleep in several clinical conditions. ⋯ No differences in daytime sleepiness, lung function and functional exercise level were observed. We conclude that melatonin can improve sleep in COPD. Further long-term studies involving larger number of patients are needed before melatonin can be safely recommended for the management of sleep disturbances in these patients.