[Conservative management of liver trauma and its complications: current gold-standard]

INTRODUCTION

The liver is the second most frequently involved organ in abdominal trauma in children. The aim of this study was to review the characteristics of liver traumas (LT) in children, its treatment and complications.

MATERIAL AND METHODS

Retrospective study of patients with LT treated between 2010-2014. We analyzed data regarding diagnosis, conservative management (CM), complications and treatment.

RESULTS

Twenty-four patients of LT with a mean age of 9.8 years (SD: 3.4) were treated at our center. Liver injury degrees according to the Organ Injury Scale of American Association for Surgery of Trauma (AAST) were: grade I (4), grade II (6), grade III (8), grade IV (5) and grade V (1). CT angiography was performed in 23 patients. Four of the six patients with initial hemodynamic instability required blood transfusion; of those, two required angioembolization for active bleeding in extrahepatic locations and a third required damage control surgery. Three patients presented late-onset complications: 2 large size bilomas which underwent spontaneous resolution and a third patient with a right biloma and section of the left bile duct who required a multidisciplinary approach. Median hospital stay was 6 days (r 1-92). With a mean follow-up of 17.75 months (SD: 16.35) (r: 2-57) long-term survival was 96%. The patient who received surgery died due to a post-traumatic brain injury.

CONCLUSION

CM seems to be the treatment of choice in LT regardless of injury degree. Surgery should be reserved for cases refractory to CM due to the associated high mortality.

Cadmium induces reactive oxygen species generation and lipid peroxidation in cortical neurons in culture

Cadmium is a toxic agent that it is also an environmental contaminant. Cadmium exposure may be implicated in some humans disorders related to hyperactivity and increased aggressiveness. This study presents data indicating that cadmium induces cellular death in cortical neurons in culture. This death could be mediated by an apoptotic and a necrotic mechanism. The apoptotic death may be mediated by oxidative stress with reactive oxygen species (ROS) formation which could be induced by mitochondrial membrane dysfunction since this cation produces: (a) depletion of mitochondrial membrane potential and (b) diminution of ATP levels with ATP release. Necrotic death could be mediated by lipid peroxidation induced by cadmium through an indirect mechanism (ROS formation). On the other hand, 40% of the cells survive cadmium action. This survival seems to be mediated by the ability of these cells to activate antioxidant defense systems, since cadmium reduced the intracellular glutathione levels and induced catalase and SOD activation in these cells.

SNAP, a NO donor, induces cortical neuron death by a mechanism in which the caspase pathway is implicated

In this paper, we present data which demonstrate that, in cortical neurons, SNAP induces loss in cell viability as evaluated by the XTT test. This cell death started at 250 microM SNAP when the treatment was performed in a serum-free medium and at 10 microM when the treatment was given in the presence of serum. This death was mediated, at least in part, by an apoptotic mechanism detected by flow cytometry and DNA fractionation. The highest SNAP concentrations induced a dual behavior on caspase-3 activity. Concentrations of 250 microM in the absence of serum and 10 microM to 300 microM in the presence of serum produced caspase-3 activation. This indicates that NO induces neuronal death by an apoptotic mechanism in which the caspase pathway is implicated. Higher SNAP concentrations (500 microM to 1 mM) diminished the caspase-3 activity to levels similar or even lower than control values. This profile was observed in the absence as well as in the presence of serum in the medium. The caspase-3 inhibition mediated by the highest SNAP concentrations did not imply NO cellular protection since the caspase-3 inhibition mediated by these SNAP concentrations neither correlated with cellular viability nor with cellular apoptosis. The possible mechanism of caspase-3 inhibition at the highest SNAP concentrations used is discussed.

Effect of various depolarizing agents on endogenous amino acid neurotransmitter release in rat cortical neurons in culture

The purpose of this study is to determine whether differences in membrane potential and/or intracellular Ca2+ increments are implicated in a programmed release of amino acid neurotransmitters (aspartate, glutamate, glycine and GABA) in cortical neurons in culture. According to our results, it is possible to assume that difference in membrane potential is not the only signal which starts the amino acid neurotransmitter release, but there are other necessary conditions at the start of this amino acid release. One of these conditions could be the increment in intracellular Ca2+, but our results indicate that, in cortical neurons in culture, the total intracellular Ca2+ increments are not important on release levels, but are the stimulating agent which produces this intracellular Ca2+ increment. From these results we may infer: (1) that in rat cortical neurons there are neurons which contain and release glutamate, aspartate, glycine and GABA, (2) that in cortical neurons the 36.6 +/- 5.8% of the neurons are GABA-ergic, (3) that the membrane potential and the total intracellular calcium are not only responsible for the release of these amino acids but also the depolarizing agent which plays an important role in this release, and (4) that glutamate and aspartate and glutamate and GABA are localized in different vesicular pools or in different cell neurons.

Comparative study between 4-aminobutyrate-2-oxoglutarate aminotransferase (GABA-T) from rat forebrain and cerebellum

In this study differences in the biochemical properties of 4-aminobutyric acid aminotransferase (GABA-T) from forebrain and cerebellum were detected. These differences may be related to: a) the characteristics of the catalytic site, b) the substrate affinities and c) their pyridoxal-phosphate requirements which suggests that PLP could be a physiological regulator of these forms of brain GABA-T.

Glutamate dehydrogenase: some properties of the rat brain enzyme from different cellular compartments

1. Differences in the GDH activity of neuronal, glial cells and synaptosomes were detected. 2. The enzyme was measured in both directions: synthesis and degradation of glutamate. 3. Synaptosomes were the region with the highest GDH activity. 4. ADP plays an important role in the regulation of the reaction sense. 5. This effector produced higher activation on the enzyme measured in the direction of glutamate synthesis than in the sense of its degradation. 6. The enhancement produced by ADP was dependent on the enzyme localization. The ADP effect is discussed.

GABAA and GABAB sites in bovine adrenal medulla membranes

The effect of several ligands and Ca2+ ions on [3H]GABA binding to bovine adrenal medulla membranes was investigated. Without any blockade, the [3H]GABA binding showed two components, one of low affinity (Kd = 139 +/- 22 nM and Bmax = 3.2 +/- 0.4 pmol/mg protein) and the other of high affinity (Kd = 41 +/- 6 nM and Bmax = 0.35 +/- 0.26 pmol/mg protein). Muscimol specifically blocked low-affinity sites, and (-)baclofen blocked high-affinity components. Ca2+ ions were strictly necessary for maximum binding to high-affinity sites, whereas they did not significantly affect sites of the lower affinity. These results show that the bovine adrenal medulla has a GABAA receptor population of low affinity together with a GABAB receptor of high affinity.

Succinic semialdehyde dehydrogenase activity in bovine adrenal medulla and blood platelets: a comparative study with the brain enzyme

In the present paper we report the presence of succinic semialdehyde dehydrogenase (SSADH) in bovine adrenal medulla and blood platelets. Both enzymes present some analogies with the brain enzyme in terms of cofactor requirements, optimal pH, mitochondrial localizaton and inhibition by AMP. However, the activity of the platelet enzyme is 100 times lower than that of the brain and affinities of both enzymes for their specific substrate succinic semialdehyde and NAD are different. The presence of SSADH in adrenal medulla and blood platelets allows us to confirm the presence of a complete GABA bypass in these tissues, where the neurotransmitter could have important regulator functions.

GABA binding in bovine adrenal medulla membranes is sensitive to baclofen

1. The data summarized in this report reveals the existence of GABA binding in the bovine adrenal medulla membranes. 2. Since this binding was displaced not only by muscimol and bicuculline but also by baclofen, results suggest the possibility that both types of receptors (GABAA and GABAB) could be present in bovine adrenal membranes.

Possible involvement of low and high affinity GABA receptors in the chloride influx into synaptosomes

Experiments carried out in the absence or presence of GABA using a synaptosomal fraction from which endogenous GABA was as far as possibly eliminated, seem to indicate that both GABA receptors are involved in the chloride channel opening. This hypothesis is supported by results obtained in the presence of GABA agonist (muscimol) or drugs which are related to the complex GABA receptor-ionophore (diazepam and phenobarbital).

GABA-T in bovine medulla cells: kinetic properties and comparison with GABA-T from other tissues

4-aminobutyrate-2-oxoglutarate aminotransferase (GABA-T) has been found in adrenal medulla. The enzyme from this tissue is very similar to those found in other tissues in respect to their mitochondrial localization, optima pH and responses to cofactor. The enzyme from medulla has substrate km values similar to those for the brain enzyme, while it differs from those found for other tissues such as kidney, liver and platelets.

Method of assay for 4-aminobutyrate-2-oxoglutarate aminotransferase

In this paper an analytical colorimetric method is presented where 2,4-dinitrophenyl hydrazine is used to measure small amounts of succinic semialdehyde in the presence of 2-oxoglutarate. This method is applicable to the measurement of 4-aminobutyrate-2-oxoglutarate aminotransferase activity, where succinic semialdehyde formed during the enzymatic reaction has to be measured in the presence of 2-oxoglutarate.

Effect of diphenylhydantoin, granatane-3-spiro-5'-hydantoin and leptazol on mouse brain glutamate dehydrogenase, urea and ammonia levels in brain

The effect of diphenylhydantoin (DPH), granatane-3-spiro-5'-hydantoin and leptazol has been checked on both GDH activity and ammonia and urea levels in brain. Concentrations of 90 mg/kg of leptazol decreased, significantly, the ammonium and urea levels in brain with respect to normal control. DPH and G-3SH had no effect on these metabolites against normal control. The association of DPH and leptazol decreased both urea and ammonium levels in brain but the association of G-3SH and leptazol decreased, significantly, urea levels but not ammonium's. DPH, leptazol at 90 mg/kg concentration and the association of DPH or G-3SH with leptazol had no significant effect on GDH activity while G-3SH increased the enzyme activity when it was measured in the direction of glutamate degradation. DPH, G-3SH and both concentrations of leptazol decreased the GDH activity when it was checked in the direction of glutamate synthesis. The association of DPH and leptazol did not produce any effects, while the association of G-3SH-leptazol increased the enzyme activity. DPH and G-3SH and leptazol at 110 mg/kg concentration decreased the relation of GDH activity between the biosynthetic and degradative sense. The association of G-3SH-leptazol increased this relation while leptazol and its association with DPH did not affect it.

Enzymatic disappearance of hydroxylamine in the presence of GABA

This paper presents data on the elimination of hydroxylamine from Lupinus albus seeds when they were germinated in the presence of GABA and hydroxylamine. The possibility of an enzymatic reaction. ATP dependent, between GABA and hydroxylamine is discussed. Some kinetic properties from this reaction are studied.

Protection by GABA and succinic semialdehyde of seed germination and some enzymatic activities against high concentration of hydroxylamine

Hydroxylamine was found to stimulate germination of Lupinus albus at concentrations inferior to 10 mM and to inhibit it greatly at 20 mM concentration. This inhibition was partially restored by GABA or succinic semialdehyde. Hydroxylamine, at high concentrations, behaved as inhibitor in vivo on GABA 2-oxyglutarate amino-transferase and succinic semialdehyde dehydrogenase NAD-dependent, whereas it behaved as activator on succinic semialdehyde dehydrogenase NADP-dependent. No effects were observed on the enzymatic activities and the inhibited germination was partially restored, after GABA and succinic semialdehyde had been added to a growth medium with a 20 mM hydroxylamine concentration. A possible protection mechanism of GABA and succinic semialdehyde against hydroxylamine action is discussed.