Glucose tolerance in fibromyalgia.

OBJECTIVES: Fibromyalgia (FM) patients have an increased risk for glucose metabolism disturbances, and impaired glucose tolerance may be associated with symptom severity. Elevated levels of plasma lactate have been detected in FM patients. Both pyruvate and lactate are produced in glucose metabolism and reflect oxidative metabolism. The objective of our study was to analyse disturbances in glucose, pyruvate, or lactate metabolism in FM patients. METHODS: We measured plasma levels of glucose, pyruvate, and lactate during an oral glucose tolerance test in 40 non-diabetic, female FM patients and 30 age- and gender-matched healthy controls. RESULTS: FM patients showed a higher glycaemic response to the glucose load at 1 hour (F [1,68] = 10.4, P = .006) and 2 hours (F [1,68] = 7.80, P = .02), and higher glucose area under the curve (13.8 [SD 2.92] vs 11.6 [SD 2.31], P < .01), than healthy controls. Group differences were explained by higher body mass index and percentage of smokers among the FM patients. Pyruvate and lactate levels were similar in both groups. DISCUSSION: Impaired glucose regulation in FM patients is likely not due to FM itself, but to associated lifestyle factors. Our results highlight the importance of assessing the glucose regulation status and the lifestyle factors affecting glucose regulation in FM patients for prevention or early treatment of diabetes and associated complications. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03300635).

Validation of a Gas Chromatography-Mass Spectrometry Method for the Measurement of the Redox State Metabolic Ratios Lactate/Pyruvate and ß-Hydroxybutyrate/Acetoacetate in Biological Samples.

The metabolic ratios lactate/pyruvate and ß-hydroxybutyrate/acetoacetate are considered valuable tools to evaluate the in vivo redox cellular state by estimating the free NAD+/NADH in cytoplasm and mitochondria, respectively. The aim of the current study was to validate a gas-chromatography mass spectrometry method for simultaneous determination of the four metabolites in plasma and liver tissue. The procedure included an o-phenylenediamine microwave-assisted derivatization, followed by liquid-liquid extraction with ethyl acetate and silylation with bis(trimethylsilyl)trifluoroacetamide:trimethylchlorosilane 99:1. The calibration curves presented acceptable linearity, with a limit of quantification of 0.001 mM for pyruvate, ß-hydroxybutyrate and acetoacetate and of 0.01 mM for lactate. The intra-day and inter-day accuracy and precision were within the European Medicines Agency's Guideline specifications. No significant differences were observed in the slope coefficient of three-point standard metabolite-spiked curves in plasma or liver and water, and acceptable recoveries were obtained in the metabolite-spiked samples. Applicability of the method was tested in precision-cut liver rat slices and also in HepG2 cells incubated under different experimental conditions challenging the redox state. In conclusion, the validated method presented good sensitivity, specificity and reproducibility in the quantification of lactate/pyruvate and ß-hydroxybutyrate/acetate metabolites and may be useful in the evaluation of in vivo redox states.

Metformin, valproic acid, and starvation induce seizures in a patient with partial SLC13A5 deficiency: a case of pharmaco-synergistic heterozygosity.

SLC13A5/NaCT is a sodium-coupled citrate transporter expressed in the plasma membrane of the liver, testis, and brain. In these tissues, SLC13A5 has important functions in the synthesis of fatty acids, cholesterol, and neurotransmitters. In recent years, patients homozygous for recessive mutations in SLC13A5, known as SLC13A5 deficiency [early infantile epileptic encephalopathy-25 (EIEE-25)], exhibit severe global developmental delay, early-onset intractable seizures, spasticity, and amelogenesis imperfecta affecting tooth development. Although the pathogenesis of SLC13A5 deficiency remains not clearly understood, cytoplasmic citrate deficits, decreased energy status in neurons, and citrate-zinc chelation are hypothesized to explain the neurological deficits. However, no study has examined the possibility of specific pharmacological drugs and/or lifestyle changes synergizing with heterozygosity of SLC13A5 deficiency to increase the risk of EIEE-25 clinical phenotype. Here, we report on a heterozygous SLC13A5-deficient patient who demonstrated evidence of pharmaco-synergistic heterozygosity upon administration of metformin, valproic acid, and starvation. The report illustrates the importance of careful consideration of the potential adverse effects of specific pharmacological treatments in patients with heterozygosity for disease-causing recessive mutations in SLC13A5.

Rapid quantification of metabolic intermediates in blood by liquid chromatography-tandem mass spectrometry to investigate congenital lactic acidosis.

A novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been established to quantify metabolic intermediates, including lactate (Lac), pyruvate (Pyr), acetoacetate (ACAC) and 3-hydroxybutyrate (3-HB) in blood. Samples were deproteinized with methanol-acetonitrile solution, and analytes were separated on an adamantyl group-bonded reverse phase column and detected in multiple reaction monitoring mode. Total analysis time was 4 min per sample. Method validation results displayed that limits of quantification were 10.0 µmol L-1 for Lac and Pyr, and 5.0 µmol L-1for ACAC and 3-HB. The within- and between-run coefficients of variation were in the range of 1.2-6.4% for all analytes. The recoveries were ranged from 95.6 to 111.5%. The reference values of analytes were determined for the pediatric population. Duo to instability of Lac, Pyr and ACAC in vitro, a comprehensive stability assay was performed to determine optimal conditions for sample collection, pretreatment and storage. Results showed that precipitation of protein in blood at bedside combined with low storage temperature could effectively preserve the integrity of Lac, Pyr and 3-HB, but the precipitated protein accelerated degradation of ACAC. Isolation of supernatant fluid slowed degradation of ACAC. Supernatant samples could store at -20 °C for 10 days. The use of plasma or serum to determine these intermediates was not recommended. In this study, 450 samples from patients were analyzed, and 7 patients were diagnosed as congenital lactic acidosis. With the advantages of rapid, accurate and reliable, this method is very suitable for congenital lactic acidosis screening and researches related to energy metabolism.

Hyperpolarized [1,(13)C]pyruvate in lysed human erythrocytes: effects of co-substrate supply on reaction time courses.

Hyperpolarized [1,(13)C]pyruvate was injected rapidly into haemolysates in which hydrolysis of nicotinamide adenine dinucleotide (phosphate) (NAD(P))/NAD(P)H had been inhibited with nicotinamide. Haemolysates provide a stable glycolytic system in which membrane permeability is not a flux-controlling step, and they enable the concentration of NADH to be adjusted experimentally while keeping the rest of the sample with the same composition as that of the cytoplasm of the cell (albeit diluted twofold at the time of injection of the [1,(13)C]pyruvate). We showed that the maximum amplitude of the (13)C NMR signal from the [1,(13)C]L-lactate, produced from [1,(13)C]pyruvate, and the time at which it occurred was dependent on NADH concentration, as predicted by enzyme-kinetic analysis. The main feature of such curves was dictated by the immediacy of the supply of the co-substrate of lactate dehydrogenase (LDH, EC 1.1.1.27), and we posit that this also pertains in vivo in various tissues including neoplasms. By constructing an appropriate mathematical model and by using a Markov-chain Monte Carlo approach, we fitted experimental data to estimate LDH and NADH concentrations. Experiments carried out with only endogenous NADH present enabled the estimation of its effective concentration in human RBCs; the ability to make this estimate is a special feature of the rapid-dissolution dynamic nuclear polarization method. We found an endogenous NADH concentration in human RBCs two to four times higher than previously reported.

Porcine model of hemorrhagic shock with microdialysis monitoring.

BACKGROUND: A number of experimental protocols have been used to try to reproduce the clinical scenarios of hemorrhagic shock. The present study reports on an experimental swine model of controlled hemorrhagic shock that incorporates microdialysis monitoring for the evaluation of tissue perfusion and oxygenation. The aim of our study was to provide a reproducible, accurate, and reliable model for the testing and evaluation of therapeutic interventions in the area of hemorrhagic shock. METHODS: Landrace swine (n = 8) were subjected to controlled hemorrhagic shock, with a mean arterial pressure of 35 ± 5 as the endpoint. Six more pigs were used as the control group. Microdialysis monitoring of the tissue lactate/pyruvate ratio was used. The mean arterial pressure, heart rate, hematocrit, hemoglobin, and lactate/pyruvate ratio measurements were obtained just before (phase A) and 30 min after (phase B) hemorrhage in the study group; the control group underwent the same measurements at the corresponding points. RESULTS: The mean arterial pressure, hematocrit, and hemoglobin were lower (P < 0.05) in the study group than in the control group at phase B and compared with the values for the study group at phase A. Also, the lactate/pyruvate ratio and heart rate were greater (P < 0.05) in the study group than in control group at phase B and compared with the values for the study group at phase A. CONCLUSIONS: This model of hemorrhagic shock is effective and correlates with the clinical parameters of tissue oxygenation, as documented by microdialysis.

Elucidation of neuroprotective role of endogenous GABA and energy metabolites middle cerebral artery occluded model in rats.

The excitatory amino acids (EAA) like glutamate, aspartate and inhibitory neurotransmitter GABA (gama amino butyric acid) play an important role in the pathophysiology of cerebral ischemia. The objective of the present study is to elucidate the role of endogenous GABA against EAA release in different regions during ischemia. The transient focal ischemia was induced in rats by using middle cerebral artery occlusion model (MCAo). The results indicate gradual elevation of brain glutamate, aspartate and GABA level at different brain regions and attained peak level at 72 h of ischemic reperfusion (IR). At 168 h of IR the EAA levels declined to base line but GABA level was found to be still elevated. The biochemical analysis shows the depleted brain ATP, Na+K+ATPase content and triphasic response of glutathione activity. It can be concluded that time dependent variation in the EAA and GABA release, endogenous GABA can be neuroprotective and earlier restoration of energy deprivation is essential to prevent further neurodegeneration. To have efficient treatment in ischemic condition, multiple approaches like energy supply, antagonism of EAA, controlling calcium function are essential.

Mechanism of lactic acidosis in children with acute severe asthma.

OBJECTIVE: Hyperlactatemia and lactic acidosis are common in adults with acute severe asthma however only a few cases have been reported in children. Type A lactic acidosis is associated with impaired oxygen delivery; type B occurs in the presence of normal oxygen delivery and has been described to occur with excessive adrenergic stimulation. Type A and B lactic acidosis can be distinguished by the blood lactate/pyruvate ratio. Our objectives are to 1) investigate the incidence of hyperlactatemia and lactic acidosis in children with acute severe asthma, and 2) determine whether lactate elevation is type A or B. DESIGN: Prospective observational study. SETTING: University-affiliated tertiary care children's hospital. PATIENTS: All children (n = 105) with acute severe asthma admitted to the pediatric intensive care unit between May 1, 2008 and November 30, 2009 were included. INTERVENTIONS: Blood lactate concentration was measured on a blood gas analyzer for all blood gas assessments obtained for clinical care. Hyperlactatemia was defined as lactate >2.2 mmol/L and lactic acidosis as lactate >5 mmol/L and pH <7.35. If lactate concentration was >5 mmol/L, consent was requested for measuring blood lactate and pyruvate using enzymatic laboratory methods. Lactate/pyruvate ratio >25:1 indicated type A lactic acidosis. MEASUREMENTS AND MAIN RESULTS: Eighty-seven (83%) children had lactate >2.2 mmol/L and 47 (45%) had lactate >5 mmol/L. Of those with lactate >5 mmol/L, 33 (70%) had corresponding blood pH <7.35. Lactate/pyruvate ratios were obtained for 16 patients. Of these, lactate/pyruvate ratio was <10 in three patients; 10-25 in 11; >25 in one; and indeterminate in one. CONCLUSIONS: Lactic acidosis is common in children with acute severe asthma and is primarily type B occurring in the presence of normal oxygen delivery.

[Metabolic therapy and pulmonary disfunction in patients with obstetric sepsis].

The role of reamberin, a succinate-containing infusion preparation in correlation of pulmonary metabolic and respiratory disturbances in patients with obstetric puerperal sepsis was estimated. The prospective randomized study enrolled 43 patients with puerperal obstetric sepsis complicated by polyorganic deficiency (SOFA 8-10). Nineteen patients of the 1st group and 24 patients of the 2nd group were additionally treated with reamberin in a dose of 800 ml/day for 8 days. The venous and arterial difference by glucose, lactate, pyruvate, diene conjugates, malondialdehyde and ceruloplasmin was investigated. The blood gases were determined with the Ciba Corning 45 apparatus. Lower metabolic activity of the lungs with prevalence of the glucose anaerobic metabolism and lower activity of the intrapulmonary antioxidant protection were observed in the patients with obstetric sepsis. The use of reamberin in the complex therapy of obstetric sepsis promoted maintenance of the initial balance and anaeroibic and aerobic pulmonary metabolism, thus providing shorter terms of the decompensation and recovery of the lungs respiratory function.

Fructose in fetal cord blood and its relationship with maternal and 48-hour-newborn blood concentrations.

BACKGROUND: Studies have suggested that different non-glucose sugars and sugar alcohols play a role in placental and fetal metabolism. However, the role of fructose in the fetal and newborn metabolism is unclear and studies are scarce. AIM: Our objective was to investigate the presence of fructose in umbilical cord blood in full-term gestation and its relationship with maternal and 48-hour-old- newborn blood concentrations, to evaluate fructose production by the fetus and newborn infant. METHODS: Blood fructose and glucose concentrations were determined by HPLC in 26 paired samples of maternal blood, umbilical cord vein, and peripheral newborn blood at 48 h after birth. ANOVA, the Friedman Analysis of Variance on Ranks and the Pearson correlation with p<0.05 were used. RESULTS: Fructose concentration in umbilical cord blood was higher than maternal blood (p=0.024), suggesting endogenous fructose production by the fetal-placental unit via the sorbitol pathway. Fructose concentrations were higher in newborns at 48 h after birth than in the fetal umbilical cord blood (p=0.004), suggesting that fructose production is a continuous process from fetus to newborn. CONCLUSIONS: Fructose production by the sorbitol pathway, present in the fetus and newborn, is an alternative pathway in glucose metabolism probably used to maintain redox balance in the fetus. We suggest that endogenous fructose, similar to dietary ingested fructose, under physiological conditions produces the backbone for triacylglycerol and lipid synthesis in the fetus and newborn. Therefore the route for metabolizing fructose is already present in the early steps of human development.

Validation of the in vivo assessment of pyruvate dehydrogenase activity using hyperpolarised 13C MRS.

Many diseases of the heart are characterised by changes in substrate utilisation, which is regulated in part by the activity of the enzyme pyruvate dehydrogenase (PDH). Consequently, there is much interest in the in vivo evaluation of PDH activity in a range of physiological and pathological states to obtain information on the metabolic mechanisms of cardiac diseases. Hyperpolarised [1-(13)C]pyruvate, detected using MRS, is a novel technique for the noninvasive evaluation of PDH flux. PDH flux has been assumed to directly reflect in vivo PDH activity, although to date this assumption remains unproven. Control animals and animals undergoing interventions known to modulate PDH activity, namely high fat feeding and dichloroacetate infusion, were used to investigate the relationship between in vivo hyperpolarised MRS measurements of PDH flux and ex vivo measurements of PDH enzyme activity (PDH(a)). Further, the plasma concentrations of pyruvate and other important metabolites were evaluated following pyruvate infusion to assess the metabolic consequences of pyruvate infusion during hyperpolarised MRS experiments. Hyperpolarised MRS measurements of PDH flux correlated significantly with ex vivo measurements of PDH(a), confirming that PDH activity influences directly the in vivo flux of hyperpolarised pyruvate through cardiac PDH. The maximum plasma concentration of pyruvate reached during hyperpolarised MRS experiments was approximately 250 µM, equivalent to physiological pyruvate concentrations reached during exercise or with dietary interventions. The concentrations of other metabolites, including lactate, glucose and ß-hydroxybutyrate, did not vary during the 60 s following pyruvate infusion. Hence, during the 60-s data acquisition period, metabolism was minimally affected by pyruvate infusion.

Chronic rapamycin treatment causes glucose intolerance and hyperlipidemia by upregulating hepatic gluconeogenesis and impairing lipid deposition in adipose tissue.

OBJECTIVE: The mammalian target of rapamycin (mTOR)/p70 S6 kinase 1 (S6K1) pathway is a critical signaling component in the development of obesity-linked insulin resistance and operates a nutrient-sensing negative feedback loop toward the phosphatidylinositol 3-kinase (PI 3-kinase)/Akt pathway. Whereas acute treatment of insulin target cells with the mTOR complex 1 (mTORC1) inhibitor rapamycin prevents nutrient-induced insulin resistance, the chronic effect of rapamycin on insulin sensitivity and glucose metabolism in vivo remains elusive. RESEARCH DESIGN AND METHODS: To assess the metabolic effects of chronic inhibition of the mTORC1/S6K1 pathway, rats were treated with rapamycin (2 mg/kg/day) or vehicle for 15 days before metabolic phenotyping. RESULTS: Chronic rapamycin treatment reduced adiposity and fat cell number, which was associated with a coordinated downregulation of genes involved in both lipid uptake and output. Rapamycin treatment also promoted insulin resistance, severe glucose intolerance, and increased gluconeogenesis. The latter was associated with elevated expression of hepatic gluconeogenic master genes, PEPCK and G6Pase, and increased expression of the transcriptional coactivator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) as well as enhanced nuclear recruitment of FoxO1, CRTC2, and CREB. These changes were observed despite normal activation of the insulin receptor substrate/PI 3-kinase/Akt axis in liver of rapamycin-treated rats, as expected from the blockade of the mTORC1/S6K1 negative feedback loop. CONCLUSIONS: These findings unravel a novel mechanism by which mTORC1/S6K1 controls gluconeogenesis through modulation of several key transcriptional factors. The robust induction of the gluconeogenic program in liver of rapamycin-treated rats underlies the development of severe glucose intolerance even in the face of preserved hepatic insulin signaling to Akt and despite a modest reduction in adiposity.

Effects of ozone blood treatment on the metabolite profile of human blood.

Metabonomic characterization of the effects caused by ozone and other stressors on normal human blood was performed. Samples of blood obtained from healthy subjects were treated ex vivo with increasing concentrations of ozone and/or with UV radiation and heat. (1)H-NMR analysis of plasma samples after treatments showed the quantitative variation of some metabolites and the formation of new metabolites normally absent. Both the increment of some metabolites like formate, acetoacetate, and acetate and the decrement of pyruvate were of particular interest. Moreover, the oxidation of ascorbic acid and the transformation of uric acid into allantoin after ozonation within the therapeutic concentration range were observed. In the ozonated spectra, 2 unidentified peaks appeared at 2.82 ppm and 8.08 ppm. They are related to the direct antioxidant activity of albumin in the presence of ozone and they could be considered as specific markers of the blood ozonation.

Comparison of high-performance liquid chromatography with fluorescence detection versus enzymatic assay to measure blood pyruvate in clinical practice.

OBJECTIVES: Measurement of blood pyruvate allows the diagnosis of patients with mitochondrial disorders. The aim of this study was to assess the analytical performance of an HPLC and an enzymatic assay for quantifying pyruvate. METHODS: The criteria of analytical performance for each assay and the correlation between methods were evaluated. RESULTS: Both assays were linear over the range 0 to 500 micromol/L of pyruvate. The total precision of the HPLC and enzymatic method were <5% for pyruvate concentrations ranging from 28 and 213 micromol/L and 42 and 181 micromol/L, respectively. The limit of detection for the HPLC technique was determined to be 1 micromol/L and the limit of quantification was 5 micromol/L. The mean recovery for HPLC was 99%. Results for the enzymatic assay showed a limit of detection of 5 micromol/L and a limit of quantification of 10 micromol/L. The mean recovery was 90.4%. In the method comparison, the HPLC method gave values that were on average 24 micromol/L higher than the enzymatic assay. CONCLUSION: Both techniques demonstrated good analytical performance. The negative bias observed for the enzymatic assay can be explained by its lesser good recovery compared to the HPLC assay.

Metabolic assessment of gradual development of moderate experimental colitis in IL-10 deficient mice.

Evidence has linked genetic predisposition and environmental exposures to the worldwide pandemic of inflammatory bowel diseases (IBD), but underlying biochemical events remain largely undefined. Here, we studied the gradual development of colitis in Interleukin 10 deficient mice using a combination of (i) histopathological analysis of intestinal sections, (ii) metabolic profiling of blood plasma, and (iii) measurement of plasma inflammatory biomarkers. Data integration using chemometric tools, including Independent Component Analysis, provided a new strategy for measuring and mapping the metabolic effects associated with the development of intestinal inflammation at the age of 1, 8, 16, and 24 weeks. Chronic inflammation appeared at 8 weeks and onward, and was associated with altered cecum and colon morphologies and increased inflammatory cell infiltration into the mucosa and the submucosa. Blood plasma profiles provided additional evidence of loss of energy homeostasis, impaired metabolism of lipoproteins and glycosylated proteins. In particular, IL-10-/-mice were characterized by decreased levels of VLDL and increased concentrations of LDL and polyunsaturated fatty acids, which are related to the etiology of IBD. Moreover, higher levels of lactate, pyruvate, citrate and lowered glucose suggested increased fatty acid oxidation and glycolysis, while higher levels of free amino acids reflected muscle atrophy, breakdown of proteins and interconversions of amino acids to produce energy. These integrated system investigations demonstrate the potential of metabonomics for investigating the mechanistic basis of IBD, and it will provide novel avenues for management of IBD.

[l-arginine efficiency in MELAS syndrome. A case report]. / La l-arginine, une thérapeutique symptomatique efficace au cours d'un syndrome MELAS.

INTRODUCTION: Mitochondrial encephalomyopathy lactic acidosis and stoke-like episodes (MELAS) is a rare neurodegenerative disease caused by mutations of mitochondrial DNA. CASE REPORT: We report the case of a 12-year-old child with MELAS syndrome who presented with recurrent migraine-like headache and sudden blindness suggesting stroke-like episodes. Furthermore, he developed progressive muscular impairment with bilateral hearing loss. Serum lactate and pyruvate levels were elevated and the muscle biopsy showed an aspect of red-ragged fibers with Gomori trichrome. Brain imaging showed calcifications of basal ganglia on the CT scan and a parieto-occipital high signal on diffusion-weighted MRI. A genetic analysis was not performed but the presence of hearing loss in the patient's mother was suggestive of maternal transmission. Stroke-like episodes in the form of migraine-like headache and blindness were the patient's major complaint and did not improve despite analgesic drugs. After oral administration of l-arginine at the dose of 0.4mg/kg per day, stroke-like symptoms totally and rapidly disappeared. DISCUSSION: The efficiency of l-arginine in stroke-like episodes was initially reported then confirmed in a controlled study. The pathophysiology of stoke-like episodes and the mechanisms underlying the action of l-arginine are discussed.

Adequate energy-protein intake is not enough to improve nutritional and metabolic status in muscle-depleted patients with chronic heart failure.

BACKGROUND: An adequate energy-protein intake (EPI) when combined with amino acid supplementation may have a positive impact on nutritional and metabolic status in patients with chronic heart failure (CHF). METHODS AND RESULTS: Thirty eight stable CHF patients (27 males, 73.5+/-4 years; BMI 22.5+/-1.4 kg/m2), with severe depletion of muscle mass and were randomised to oral supplements of essential amino acids 8 g/day (EAA group; n=21) or no supplements (controls; n=17). All patients had adequate EPI (energy> or =30 kcal/kg; proteins >1.1 g/kg). At baseline and 2-months after randomisation, the patients underwent metabolic (plasma lactate, pyruvate concentration; serum insulin level; estimate of insulin resistance by HOMA index), nutritional (measure of nitrogen balance), and functional (exercise test, walking test) evaluations. Body weight increased by >1 kg in 80% of supplemented patients (mean 2.96 kg) and in 30% of controls (mean 2.3 kg) (interaction <0.05). Changes in arm muscle area, nitrogen balance, and HOMA index were similar between the two treatment groups. Plasma lactate and pyruvate levels increased in controls (p<0.01 for both) but decreased in the supplemented group (p<0.01 and 0.02 respectively). EAA supplemented patients but not controls improved both exercise output and peak oxygen consumption and walking test. CONCLUSIONS: Adequate EPI when combined with essential amino acid supplementation may improve nutritional and metabolic status in most muscle-depleted CHF patients.

Cadmium affects the expression of heat shock protein 90 and metallothionein mRNA in the Pacific oyster, Crassostrea gigas.

Cadmium (Cd) is a widespread nonessential heavy metal that enters the aquatic environment as a result of natural processes and human activities such as wastewater production, agriculture, and mining. To determine the effects of Cd on organisms, we investigated its time- and dose-related effects on mRNA levels of heat shock protein 90 (HSP90) and metallothionein (MT) in the gill and digestive gland and changes enzyme levels in the hemolymph of the Pacific oyster Crassostrea gigas. Full-length HSP90 cDNA was isolated from C. gigas by rapid amplification of cDNA end (RACE) techniques and found to contain 2154 nucleotides, including an open reading frame, and was predicted to encode a protein of 717 amino acids. BLAST analysis indicated that the HSP90 gene of C. gigas shared high homology with known HSP90 genes of other mollusks. The expression of HSP90 mRNA increased significantly with exposure to 0.01 ppm Cd for 11 days or 0.05 or 0.1 ppm Cd for 7 days. The expression of MT mRNA increased significantly with exposure to 0.01, 0.05, or 0.1 ppm Cd for 11 days. Glutamate oxaloacetate and glutamate pyruvate levels increased significantly with exposure to 0.05 or 0.1 ppm Cd for 7 days. These results indicate that HSP90 and MT play important roles in the physiological changes related to metabolism and cell protection that occur in Pacific oysters exposed to Cd.

The lactate:pyruvate ratio following open cardiac surgery in children.

OBJECTIVE: To explore the relationship between lactate:pyruvate ratio, hyperlactataemia, metabolic acidosis, and morbidity. DESIGN AND SETTING: Prospective observational study in the paediatric intensive care unit (PICU) of a university hospital. PATIENTS: Ninety-seven children after open cardiac surgery. Most children (94%) fell into low-moderate operative risk categories; observed PICU mortality was 1%. INTERVENTIONS: Blood was sampled on admission for acid-base analysis, lactate, and pyruvate. Metabolic acidosis was defined as standard bicarbonate lower than 22 mmol/l, raised lactate as higher than 2 mmol/l, and raised lactate:pyruvate ratio as higher than 20. MEASUREMENTS AND RESULTS: Median cardiopulmonary bypass and aortic cross-clamp times were 80 and 46 min. Metabolic acidosis occurred in 74%, hyperlactataemia in 42%, and raised lactate:pyruvate ratio in 45% of children. In multivariate analysis lactate:pyruvate ratio increased by 6.4 in children receiving epinephrine infusion and by 0.4 per 10 min of aortic cross-clamp. Duration of inotropic support increased by 0.29 days, ventilatory support by 0.27 days, and PICU stay by 0.42 days, for each 1 mmol/l increase in lactate. Neither standard bicarbonate nor lactate:pyruvate ratio were independently associated with prolongation of PICU support. CONCLUSIONS: Elevated lactate:pyruvate ratio was common in children with mild metabolic acidosis and low PICU mortality. Hyperlactataemia, but not elevated lactate:pyruvate ratio or metabolic acidosis, was associated with prolongation of PICU support. Routine measurement of lactate:pyruvate ratio is not warranted for children in low-moderate operative risk categories.