Ethane: a marker of lipid peroxidation during cardiopulmonary bypass in humans

The goals of this study were to (1) determine the utility of quantification of ethane as a marker of ischemia-reperfusion during human cardiopulmonary bypass (CPB); and (2) determine, using an animal model for this surgical procedure, whether the mode of surgical approach produced increases the quantity of exhaled ethane. Human CPB was initiated following standard anesthetic and monitoring regimens. Samples of gas were collected at baseline and at multiple defined time points throughout the studies. Ethane was determined using cryogenic concentration and gas chromatography. Sternotomy increased exhaled ethane compared to baseline (p < .007; 5.8 +/- 1.7 vs. 3.0 +/- 0.7 nmol/m2 x min); ethane returned to baseline levels prior to the initiation of CPB. Aortic unclamping produced ethane elevation (p < .05; 2.3 +/- 0.8 vs. 1.5 +/- 0.4 nmol/m2 x min) with the levels being related to a lower cardiac index and a higher systemic vascular resistance post aortic unclamping. Termination of CPB significantly increased ethane levels compared to baseline (p < .002; 4.8 +/- 1.7 vs. 3.0 +/- 0.7 nmol/m2 x min). Independent variables that correlated with increased ethane measurements included a higher arterial blood pH on bypass and the change in hemoglobin pre- and post-CPB. Electrocautery, but not scalpel, incision of the porcine abdominal wall increased ethane levels significantly (p < .02). These results indicate that exhaled ethane may be a valuable marker of lipid peroxidation during and following CPB.     

Maternal hypertension and neurodevelopmental outcome in very preterm infants

AIM: To determine the outcome of preterm infants born to mothers with hypertension during pregnancy, and preterm controls. METHODS: 107 infants of 24-32 weeks gestation, born to hypertensive mothers, and 107 controls matched for gestational age, sex, and multiple pregnancy, born to normotensive mothers, were prospectively enrolled over 2 years. Information on maternal complications and medication was obtained and neonatal mortality and morbidities recorded. Survivors were followed up to at least 2 years, corrected for prematurity. RESULTS: One third of the hypertensive mothers were treated with antihypertensive drugs, while 18% received convulsion prophylaxis with phenytoin. Magnesium sulphate was not prescribed. Both groups had a mean gestational age of 29.9 weeks, with the study infants having a significantly lower birthweight than the controls. Four study and three control infants died in the neonatal period. Cerebral palsy was not diagnosed in any infant of a hypertensive mother compared with five of the controls. The mean general quotient for the two groups was very similar and no difference in the incidence of minor neuromotor developmental problems was shown. CONCLUSIONS: Maternal hypertension seems to protect against cerebral palsy in preterm infants without increasing the risk of cognitive impairment. This was independent of the use of maternally administered magnesium sulphate.     

Benfluorex, a hypotriglyceridemic drug, reduces lipid peroxidation and alleviates adverse metabolic complications of copper deficiency

To provide histological diagnoses of brain diseases, CT-guided stereotactic brain biopsy (CT-SBB) has been widely used because of its less invasive technique compared with open brain biopsy (OBB). However, CT-SBB is not always diagnostic. We report a case of multiple intracranial tuberculoma whose diagnosis was not made by CT-SBB but by OBB. The patient is a 46-year-old man with insulin-dependent diabetes mellitus who had been receiving immunosuppressive agents (azathioprine, cyclosporin, and prednisolone) after renal transplantation for diabetic renal failure for 9 years. He gradually developed febrile, headache and unsteady gait. Brain MRI demonstrated multiple intracranial lesions involving left fronto-temporal and right parietal lobes, left cerebellar hemisphere, and the fourth ventricle. Although the MRI findings were consistent with those of previously reported cases of intracranial tuberculoma, other conditions, such as malignant lymphoma and toxoplasmosis, were not ruled out. Therefore, CT-SBB targeting the left temporal lobe lesion was done for definitive diagnosis, but it revealed only mild perivascular infiltration of mononuclear cells and hemorrhage. He was transferred to our clinic for further evaluation. On examination, mild truncal and limb ataxia on the left were noted in addition to the neurological findings corresponding to diabetic retinopathy and neuropathy. Despite vigorous laboratory examinations, including repeated bacterial cultures and PCR of cerebrospinal fluid, no evidence of tuberculous infection was obtained. A tentative diagnosis of multiple intracranial tuberculoma was made, and anti-tuberculous drugs (isoniazid 400 mg, ethambutol 750 mg, and pyrazinamide 1.5 g) were administered. Since his symptoms deteriorated because of ventricular dilatation resulting from the enlarged lesion in the fourth ventricle after a temporary clinical improvement, VP-shunting and OBB from the left temporal lobe lesion were done. The excised lesion was firmly encapsulated and the histological examination revealed typical pathology of tuberculoma. Ziehl-Neelsen staining and PCR for Mycobacterium tuberculosis of the biopsied specimen were also positive. Further administration of increased doses of anti-tuberculous drugs (isoniazid 600 mg, ethambutol 500 mg, pyrazinamide 2.0 g and intramuscular injection of streptomycin 0.3 g twice a week) eventually ameliorated the symptoms and shrank the lesions. In case of intracranial tuberculoma, the needle of CT-SBB may not penetrate the firm capsule of tuberculoma and only the surrounding brain tissue may be obtained as in the present case. Therefore, it is recommended to consider OBB from the beginning for definitive diagnosis of intracranial tuberculoma. Paradoxical worsening of the clinical and laboratory findings of tuberculosis in spite of appropriate anti-tuberculous therapy as seen in the present case has been described in both pulmonary and extra-pulmonary tuberculosis. The phenomenon, called transient worsening, could happen and we have to keep it in mind during the treatment of intracerebral tuberculoma.     

Randomised controlled trial of L-carnitine as a nutritional supplement in preterm infants

AIMS: To evaluate the effect of L-carnitine supplementation (25 mg/kg/d) on the growth and incidence of hypoglycaemia in preterm infants. METHODS: A double blind, placebo controlled randomised trial, stratified for gestational age, was conducted of 86 preterm infants between 28 and 34 gestational weeks. The median gestational ages in the carnitine group and placebo groups were 30.7 weeks (range 28.0 to 33.6) and 31.4 weeks (range 28.0 to 33.9), respectively. The median birthweights were 1.557 kg (range 0.944 to 2.275) and 1.645 kg (range 0.885 to 2.545), respectively. RESULTS: Mean plasma free carnitine concentrations were below values for normal term infants in both groups on day 1 (carnitine group 44.8 mumol/l, placebo group 25.5 mumol/l) in the placebo group on day 7 (50.7 mumol/l), but in neither group on days 14 and 28. Total, free, and acylcarnitine concentrations were significantly increased in both urine and blood in the L-carnitine group. There was no significant difference between the placebo and carnitine supplemented groups in growth rate, as assessed by weight, length, skinfold thickness and head circumference measurements, or in the incidence of episodes of hypoglycaemia. CONCLUSION: The addition of carnitine as a nutritional supplement at a dose of 25 mg/kg/day did not improve growth in our group of preterm infants nor protect them from episodes of hypoglycaemia.     

The correlation of elevated levels of an index of lipid peroxidation (MDA-TBA) with adverse outcome in the very low birthweight infant

The objective of this study was to examine the relationship between malondialdehyde-thiobarbituric acid (MDA-TBA) levels, as a measure of lipid peroxidation, in very low birthweight (VLBW) infants and outcome measures. A prospective observational longitudinal study was carried out in two level III neonatal units in the South Island of New Zealand measuring MDA-TBA levels in 61 VLBW infants in 1993. MDA-TBA levels were measured in (i) maternal plasma within 48 h of parturition, (ii) cord plasma, and (iii) infants' plasma at 2, 7, 14 and 28 days of age and correlated with antenatal and postnatal factors. Elevated levels of plasma MDA-TBA at 7 days were associated with adverse respiratory and ophthalmological outcome in the VLBW infants. Elevated MDA-TBA levels were measured at sample times close to the time of death in the infants who died. These results substantiate previously reported preliminary observations and support the hypothesis that oxidative injury, particularly within the first 7 days of life, is associated with the development of the long-term complications of the pre-term infant. MDA-TBA levels appear to be a useful measure to continue to explore the role of free radical mediated disease in the VLBW infant.     

Assessment of uterine arterial notching as a screening test for adverse pregnancy outcome

Recombinant papillomavirus-like particles have recently been shown to be highly effective for the prevention of papillomavirus infections and associated tumors, and a virus-like particle-based vaccine against the most prevalent HPV causing genital infection in humans will be developed in the near future. Another use of these virus-like particles may lie in gene therapy and DNA immunization. We report here that human papillomavirus-like particles composed of the major capsid protein (L1) of HPV-16 are able to package unrelated plasmid DNA in vitro and then to deliver this foreign DNA to eukaryotic cells with the subsequent expression of the encoded gene. The results indicate higher gene transfer than with DNA alone or with liposome. Virus-like particles are a very promising vehicle for delivering genetic material into target cells. Moreover, the preparation of the gene transfer vehicle is relatively easy.     

Breath ethane as a marker of reactive oxygen species during manipulation of diet and oxygen tension in rats

Breath ethane, O2 consumption, and CO2 production were analyzed in 24-mo-old female Fischer 344 rats that had been fed continuously ad libitum (AL) or restricted 30% of AL level (DR) diets since 6 wk of age. Rats were placed in a glass chamber that was first flushed with air, then with a gas mixture containing 12% O2. After equilibration, a sample of the outflow was collected in gas sampling bags for subsequent analyses of ethane and CO2. The O2 and CO2 levels were also directly monitored in the outflow of the chamber. O2 consumption and CO2 production increased for DR rats. Hypoxia decreased O2 consumption and CO2 production for the AL-fed and DR rats. These changes reflect changes in metabolic rate due to diet and PO2. A significant decrease in ethane generation was found in DR rats compared with AL-fed rats. Under normoxic conditions, breath ethane decreased from 2.20 to 1.61 pmol ethane/ml CO2. During hypoxia the levels of ethane generation increased, resulting in a DR-associated decrease in ethane from 2.60 to 1.90 pmol ethane/ml CO2. These results support the hypothesis that DR reduces the level of oxidative stress.     

Pulmonary function tests as a predictor of chronic lung disease in ventilated preterm infants

BACKGROUND: The objective of this study was to determine if the value of respiratory system compliance and lung resistance could be a good predictor of chronic lung disease (CLD) in an early stage of this disease. METHODS: The study was carried out on 48 preterms infant (BW < 1500 g) who were ventilated for respiratory distress, calculating pulmonary mechanics at 3, 5, 7 and 10 days of life with a standardized protocol of measurements. RESULTS: Infants who did not develop CLD showed higher values of respiratory system dynamic compliance (Crsdyn) than the CLD group since the 5th day of life (p < 0.001). The values of lung resistance show a statistical significant difference between groups since the 7th day of life. CONCLUSIONS: These findings indicate that, with a well standardized method of measurements, the value of Crsdyn can well be a good predictor and a sensible prognostic factors for CLD.     

Infant auditory discrimination in preterm and full-term infants as a predictor of 5-year intelligence.

Examined the relation between responsiveness to auditory novelty in full-term and preterm infants at 4 mo and subsequent intellectual performance at 5 yrs of age. At 4 mo, cardiac response to repetitive and novel auditory stimulation was assessed using a variable-trials habituation procedure for 9 full-term and 19 preterm infants. Ss were followed until the age of 5 yrs, and intellectual performance was measured using the Stanford-Binet Intelligence Scale. A statistically significant correlation of .60 was found between infant novelty response scores and 5-yr intelligence scores. Mother's education also related to 5-yr performance, although not significantly when the novelty response was partialed out. Results suggest that measures of early perceptual-memory development may reflect early cognitive processes necessary for later intellectual performance. Within the preterm group, there was a sample of male infants with below-average intelligence at 5 yrs. These Ss failed to respond to novelty, and their mothers had not completed high school. Thus, a subsample of high-risk Ss can be identified early in life. A significant positive relation was also found between scores on the Bayley Scales of Infant Development and intelligence at 5 yrs of age. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

F4-isoprostanes as specific marker of docosahexaenoic acid peroxidation in Alzheimer's disease

F2-isoprostanes are prostaglandin-like compounds derived from free radical-catalysed peroxidation of arachidonic acid. Peroxidation of eicosapentaenoic acid produces F3-isoprostanes, whereas peroxidation of docosahexaenoic acid would give F4-isoprostanes. This study demonstrates the presence of esterified F4-isoprostanes in human brain and shows that levels are elevated in certain brain cortex regions in Alzheimer's disease. Our data with Alzheimer's disease suggest that analysis of F4-isoprostanes will provide new opportunities to study lipid peroxidation in the neurodegenerative diseases.     

Respiratory pentane: a measure of in vivo lipid peroxidation applied to rats fed diets varying in polyunsaturated fats, vitamin E, and selenium and exposed to nitrogen dioxide

Pentane is one decomposition product of omega 6-unsaturated lipid hydroperoxides. The measurement of respiratory pentane is one of the most sensitive in vivo tests of lipid peroxidation. This measurement was applied to test the ability of a low level, short-term exposure of rats of nitrogen dioxide to induce lipid peroxidation. When exposed to 4.48 ppm nitrogen dioxide for 60 min, no increase in pentane production was detected. For 10 weeks prior to exposure, the rats were fed Torula yeast-based diets with 10% stripped lard or 10% stripped corn oil. The ratios of basal pentane production by rats fed the following antioxidants were for corn oil- and lard-fed rats, respectively: 40 I.U. vitamin E/kg and 0 selenium: 0 vitamin E and 0.1 ppm selenium: 0 vitamin E and 0 selenium, 1:2.2:5.8 and 1:1.9:3.5. Pentane production was significantly (P<0.05) greater by corn oil-fed rats than by lard-fed rats only when both vitamin E and selenium were absent from the diet.     

Perinatal and neonatal outcome and late pulmonary sequelae in infants born after preterm premature rupture of membranes

The regulation of the lytic and lysogenic development in the life cycle of bacteriophage Mu is regulated in part by its repressor, c, which binds to three operator sites, O1, O2 and O3, overlapping two divergent promoters. The oligomeric structure of this repressor protein was investigated by hydrodynamic and biochemical methods. Size-exclusion chromatography, analytical ultracentrifugation, dynamic light scattering, crosslinking and direct electron microscopy observations suggest that c exists primarily as a hexamer with a molecular mass of 120-140 kDa at low concentrations, i.e. in the 10-microM range. This molecule undergoes a self-assembly process leading to dodecamers and higher order species as the concentration is further increased in a manner depending on the nature of the solvent. Our results also suggest that these species have an elongated structure, and a possible arrangement of the subunits within the hexamer is proposed. The implication of this unusual quaternary structure for a repressor in its interaction with the operator sites O1 and O2 remains to be elucidated.     

Enhanced lipid peroxidation in patients positive for antiphospholipid antibodies

The mechanism leading to the formation of antiphospholipid antibodies (aPL) is still unknown. Because an in vitro study suggested that aPL may derive from pro-oxidant conditions, we sought a relationship between aPL and isoprostanes, indices of lipid peroxidation in vivo. Thirty patients with systemic lupus erythematosus have been studied. Seventeen (56.6%) were positive for aPL because they had lupus anticoagulant and/or high titer of anticardiolipin antibodies (aCL). Plasma levels of tumor necrosis factor (TNF ) and urinary excretion of two isoprostanes, 8-epi-PGF2alpha and IPF2alpha -I, free radical catalyzed oxidation products of arachidonic acid, were measured. Patients with systemic lupus erythematosus had higher urinary excretion of 8-epi-PGF2alpha and IPF2alpha -I than controls; urinary excretion of the two isoprostanes was highly correlated (Rho = 0.74, P < .0001). Urinary 8-epi-PGF2alpha was highly correlated with both aCL titer (Rho = 0. 70, P < .0001) and TNF (Rho = 0.84, P < .0001), a measure of disease severity. Excretion of this isoprostane was also higher in those patients who exhibited aPL (P < .0001). Comparable correlations were observed with the isoprostane IPF2alpha -I. No difference of 8-epi-PGF2alpha was observed between patients with and without previous history of thrombosis. This study, showing the existence of a close association between aPL and increased in vivo lipid peroxidation, supports the hypothesis that these antibodies may result from pro-oxidative conditions and suggests that inflammation may play an important role.     

Splenic macrophages in preterm infants: a necropsy study

AIMS: To study the frequency and nature of histiocytes in the splenic red pulp of infants who died following complicated immaturity/prematurity. METHODS: Twenty four preterm/immature infants were investigated. Frozen sections of formalin fixed splenic tissue were stained with Oil Red O. Paraffin wax sections from the same tissue were conventionally stained with haematoxylin and eosin. Immunohistochemistry was carried out for a number of macrophage markers. The administration of Intralipid was compared with the presence and extent of tissue macrophages. RESULTS: The spleens of 10 infants showed varying degrees of Oil Red O positivity ranging from mild to strong. In all these cases varying numbers of macrophages were confirmed in the splenic parenchyma in ordinary sections. The immunomarkers indicated that the histiocytes belonged to the macrophage phagocytic system. Of the 10 cases with splenic macrophages all had received Intralipid. Of those not receiving Intralipid none showed splenic macrophages. Seven had received Intralipid but did not have splenic macrophages; they had either only received small amounts of Intralipid or Intralipid was discontinued before death. CONCLUSIONS: Splenic macrophages are common at necropsy in immature/preterm infants. The macrophages are most lucidly demonstrated using Oil Red O staining in frozen sections. There is a strong association between the presence of splenic macrophages and Intralipid administration.     

Lipid peroxidation in healthy fetuses, preterm and fullterm neonates

Thrombolytic therapy has been accepted in the treatment of acute myocardial infarction. Given historical recommendations that thrombolytic therapy is contraindicated in patients receiving CPR, its potential clinical benefit for facilitating conversion of rhythm in patients in refractory cardiac arrest has not been investigated. We present three case reports in which patients with confirmed acute myocardial infarction had a witnessed cardiac arrest in the ED. Standard Advanced Cardiac Life Support measures failed in all three cases. A bolus infusion of tissue plasminogen activator was administered during CPR in refractory ventricular fibrillation (two cases) and pulseless ventricular tachycardia (one case). Patients were given tissue plasminogen activator and had defibrillation, followed by a spontaneous return of circulation, with resuscitation and subsequent discharge. No postarrest sequelae were observed as a result of thrombolytic use during the resuscitative process. We conclude that bolus thrombolytic infusions during CPR may facilitate spontaneous return of circulation in select patients with confirmed acute myocardial infarction, witnessed cardiac arrest in the ED, and refractory ventricular fibrillation or tachycardia.     

Ischemic tolerance and lipid peroxidation in the brain

Using a modified method of focal ischemic preconditioning (FIP) followed by permanent middle cerebral artery occlusion (MCAO), we studied the effects of ischemic tolerance on infarct volume. The FIP was achieved by obstructing the blood flow into the MCA using miniature clamps at two points simultaneously. The first point was proximal to its origin and the second was where it intersects the middle cerebral vein. In rats subjected to three short conditioning periods (3 x 3 min with 7 min reperfusion between occlusions), there were significant reductions in the infarct volume in the cerebral cortex induced by the subsequent MCAO in FIP-treated rats compared with sham-operated controls. This rapid FIP-induced ischemic tolerance to subsequent MCAO occurred within 1 day and lasted for 5 days. Tissue lipid peroxidation in the cortex was significantly reduced for up to 2 days after FIP. In contrast, lipid peroxidation increased rapidly after MCAO. A significant reduction in this increase was observed in FIP-treated rats, suggesting a correlation with the subsequent reduction in the infarct volume.