Lipid peroxidation assessment by malondialdehyde measurement in parenteral nutrition solutions for newborn infants: a pilot study.

AIM: To determine malondialdehyde (MDA) concentrations in parenteral nutrition admixtures exposed to ambient room light, and in the serum of neonates. METHODS: Using a new method to measure MDA specifically, this study analysed MDA of lipid-containing all-in-one admixtures provided by the pharmacy, with a composition identical to that used in routine clinical conditions. First, 12 admixtures were exposed to ambient light for 24 h, in the neonatal intensive care unit. Secondly, 18 solutions were either exposed to (n = 9) or protected from ambient light (n = 9) during the same period. Samples of admixtures were collected at baseline and 24 h later, for MDA measurement. Serum MDA was also randomly measured in orally fed healthy neonates. RESULTS: After 24 h exposure to ambient room light, MDA concentrations in parenteral nutrition admixtures increased from 179 (129, 348) nmol l(-1) to 5800 (1632, 14679) nmol l(-1) (p = 0.0002) [50th (10th, 90th) centiles]. When admixtures were protected from light, the increase in MDA was significantly lower than without protection: 187 (60, 429)nmol l(-1) versus 13 696 (3472, 26 049)nmol l(-1) (p = 0.0003). In 54 infants with a gestational age of 33 (28, 39) wk and a birthweight of 1750 (960, 3388) g, plasma MDA concentrations were 173 (98, 315) nmol l(-1). CONCLUSION: In solutions protected from light, MDA concentrations were low and were close to the serum MDA concentrations observed in orally fed neonates. Administration of all-in-one admixtures containing lipids in ambient lighting results in intravenous infusion of high levels of MDA which may present an additional source of morbidity in immature infants. This study confirms the need to protect parenteral admixtures from light.

c-JUN gene induction and AP-1 activity is regulated by a JNK-dependent pathway in hypoxic HepG2 cells.

Hypoxia is an important pathophysiological stress that occurs during blood vessel injuries and tumor growth. It is now well documented that hypoxia leads to the activation of several transcription factors which participate in the adaptive response of the cells to hypoxia. Among these transcription factors, AP-1 is rapidly activated by hypoxia and triggers bFGF, VEGF, and tyrosine hydroxylase gene expression. However, the mechanisms of AP-1 activation by hypoxia are not well understood. In this report, we studied the events leading to AP-1 activation in hypoxia. We found that c-jun protein accumulates in hypoxic HepG2 cells. This overexpression is concomitant with c-jun phosphorylation and JNK activation. Moreover, we showed that AP-1 is transcriptionally active. We also observed that AP-1 transcriptional activity is inhibited by a MEKK1 dominant negative mutant. Moreover, the MEKK1 dominant negative mutant as well as deletion of the AP-1 binding sites within the c-jun promoter inhibited the c-jun promoter activation by hypoxia. All together, these results indicate that, in hypoxic HepG2 cells, AP-1 is activated through a JNK-dependent pathway and that it is involved in the regulation of the c-jun promoter, inducing a positive feedback loop on AP-1 activation via c-jun overexpression.

Evaluation of parenchymal and nonparenchymal cell injury after different conditions of storage and reperfusion.

We used the isolated perfused rat liver model (IPRL) to assess parenchymal and nonparenchymal cell integrity after different conditions of storage and reperfusion. Two studies were performed. In study 1, the IPRL was applied to evaluate the effects of 30 min of normothermic reperfusion with Elohes solution, enriched William's medium (Wif), or Carolina rinse solution (CRS) following 24 h of cold preservation in high-K+ or high-Na+ UW solution. As indicated by creatine kinase-BB (CK-BB) release, reperfusion with CRS provided greater protection of endothelial cells after storage in high-K+ UW solution than after storage in high-Na+ UW solution. In study 2, livers were cold-preserved (24 h, 4 degrees C) in either high-K+ or high-Na+ UW solution, then flushed with either CRS or Wif solution at room temperature before reperfusion (120 min, 37 degrees C) with 5% albumin-William's medium E. There was no statistical difference between the rinse solutions for bile flow and transaminases release. However, CRS improved bile indocyanine green excretion, which is known to be a marker of parenchymal and nonparenchymal cell integrity. Therefore, we can assume that this rinse solution protects rat liver grafts from reperfusion-induced microvascular damage.

High-Na+ low-K+ UW cold storage solution reduces reperfusion injuries of the rat liver graft.

The isolated perfused rat liver model was used to assess graft viability after 24 h of cold preservation. Two solutions were compared for liver preservation: Belzer's original UW solution (high-K+ UW) and a solution containing the same components but with inverted concentrations of sodium and potassium (high-Na+ UW). During the 120 min of normothermic reperfusion, livers preserved in the high-Na+ UW solution released lower levels of creatine kinase-BB isoenzyme, transaminases (ALT and AST), and potassium than those preserved in the high-K+ UW solution. Bile flow and biliary excretion of indocyanine green increased when livers were preserved in the high-Na+ UW solution. We found no statistical differences for oxygen consumption and tissue ATP concentration. The results of this study support the concept that a high-Na+ UW solution is a more effective means of preserving rat livers, at least after 24 h of cold-storage and 120 min of reperfusion in the isolated perfused model, than the original high-K+ UW solution. Liver preservation in the high-Na+ UW solution reduces damage to sinusoidal endothelial and hepatocellular cells. The use of an extracellular-like Belzer cold storage solution eliminates potassium-related problems in cold preservation and subsequent normothermic reperfusion while keeping all the qualities of the original UW solution.

Energy expenditure during allogeneic and autologous bone marrow transplantation.

Resting energy expenditure (REE) was measured by indirect calorimetry during allogeneic and autologous bone marrow transplantation in order to evaluate the evolution in allogeneic and autologous recipient patients. REE values obtained with indirect calorimetry and compared with values using the Harris-Benedict formula were different. Evolution of REE during aplasia were significantly different in autologous and allogeneic recipients with an increase 11.5 ' 10.8 cent for autologous and a decrease of - 7.3 ' 8.9 cent in allogeneic bone marrow transplantation (BMT) patients. There were no differences in nutritional status and REE before BMT, at discharge and 1 month after discharge between the two groups but all patients had inflicted damage on their nutritional status at discharge from hospital after BMT. However, these patients differed because of the decrease in oral nutritional intake and an increase in the length of aplasia and hospital stay in allogeneic patients. Currently, there is no proof that recommendations for nutritional interventions or results of nutritional investigations in allogeneic BMT can be extrapolated in autologous patients. Harris-Benedict formula does not estimate the energy expenditure of patients submitted to massive chemotherapy and BMT with enough precision because of the great differences in individuals.

Nifedipine improves recovery function of kidneys preserved in a high-sodium, low-potassium cold-storage solution: study with the isolated perfused rat kidney technique.

BACKGROUND: Extracellular types (high-Na) of cold-storage solution (CSS) have been shown to be more effective in preserving kidneys than intracellular CSS (high-K). On the other hand, calcium entry blockers (CEB) have been demonstrated to improve graft function when administered after and/or prior to transplantation. The ischaemia reperfusion syndrome involves, in part, an alteration in intracellular calcium metabolism that induces an increase in renal vascular resistances (RVR) and other cellular dysfunction, and high-K CSS per se are vasoconstrictive. Since CEB act via a modification in intracellular calcium metabolism on vascular smooth muscle, glomerular, and tubular cells, we evaluated the actual benefit on CEB on kidneys preserved in Belzer's CSS (K-UW) and a high-Na version of Belzer's CSS (Na-UW). METHOD: The isolated perfused rat kidney (IPK) was used, first as a vascular bed to test the effects of CSS on RVR, and the influence of nifedipine. Second, the recovery function of the IPK was assessed by GFR and tubular Na reabsorption, after 24 h preservation in K-UW and Na-UW, with or without nifedipine. Results were compared with a control group in which renal function was measured without prior cold-storage. RESULTS: K-UW but not Na-UW induced an increase in RVR when flushed into the kidney. This vasoconstriction is prevented by nifedipine. K-UW CSS was more deleterious to renal function than Na-UW. Addition of nifedipine to the flush, the CSS for 24 h, and to the normothermic reperfusate further improved recovery function of the IPK cold stored in Na-UW but not in K-UW, without any modification of RVR. CONCLUSION: Nifedipine may be of potential effect in attenuating ischaemic injury by a mechanism which does not involve its vasodilatory properties.

Standard doses versus repeated high doses of epinephrine in cardiac arrest outside the hospital.

Among all of the cathecolamines used for cardiac arrest treatment, epinephrine injection during cardio-pulmonary resuscitation is currently the most powerful means of enhancing effectiveness; however, deliberations about the optimal dosage have recently become intense. In the SAMU of Lyon (F), we conducted a double blind prospective randomized study over an 18-month period, comparing repeated standard-dose epinephrine (1 mg) and repeated high-dose epinephrine (5 mg) in the management of cardiac arrest outside the hospital. Five-hundred thirty-six patients were enrolled with 265 in the standard-dose group and 271 in the high-dose group; both groups are globally similar. One-hundred eighty-one (33.8%) patients returned to spontaneous circulation (R.O.S.C.); 85 in the standard-dose group (32%) and 96 in the high-dose group (35.5%). One-hundred nineteen patients (22.2%) were admitted; 54 in the standard-dose group (20.4%) and 65 in the high-dose group (24%). At 6 months nine patients (7.6%) were alive; three patients from the standard-dose group (5.5%) and six from the high-dose group (9.2%). We never noticed cardiac or neurologic adverse effects with the high doses. The results of this study are not statistically significant, but we observed a marginal trend towards repeated 5 mg epinephrine doses. A large French multicentre study is now necessary.

Evaluation of a high sodium-low potassium cold-storage solution by the isolated perfused rat kidney technique.

The isolated perfused rat kidney (IPK) model was used to assess initial renal function after 24 h preservation in 3 different cold storage solutions: EuroCollins (EC), a solution prepared according to the formulation of Belzer's solution (High-K+ UW) and a high Na(+)-low K+ Belzer UW solution (High-Na+ UW). GFR and FRNa were measured after 24 h cold storage in each of the solutions during 60 min, and were compared to values obtained in a control group in which renal function was measured immediately after the kidneys had been harvested. ATP and CP were measured in fresh renal tissue, in kidneys preserved for 24 h in each solution, in control IPK, and in reperfused IPK after they had been preserved for 24 h. Main results showed that preservation in either solution caused a dramatic decrease in GFR and in FRNa within the first 60 min following reperfusion of cold-stored kidneys. However FRNa was significantly higher in the High-Na+ UW group. ATP and CP content were decreased to approximately 10% of basal values in all experimental groups after cold-storage. Normothermic reperfusion of IPK after cold-storage induced a restoration of ATP levels, but CP content decreased further. There was no significant difference in ATP and CP content between cold-storage solutions, nor any correlation between metabolic and functional parameters.