Coeliac disease: always something to discover

The authors present more than 20 years' experience with coeliac disease, with a summary of their published studies. Hair shaft characteristics were determined by scanning electron microscopy. Hair diameter was significantly lower and cuticular erosion scores higher in those who were not on gluten-free diets as compared to controls, showing a tendency towards normal values following start of gluten-free diets. Proton-induced X-ray emission showed significantly lower zinc content of the hair shaft in the group with acute coeliac disease and after a short-term diet, which approached the normal range only after a year-long diet. The serum prolactin levels in healthy controls and in coeliac patients on the diet were within normal limits, whereas in children with coeliac disease taking gluten in their meals, a significant hyperprolactinaemia was found. The erythrocyte glutathione content of coeliac children was elevated, and the glutathione disulfide level was significantly decreased, as compared to values in normal controls. The erythrocyte glutathione disulfide level and glutathione disulfide/erythrocyte glutathione ratio in coeliac children also differed from those in children with iron deficiency. With genotyping, the DQB1*0201/2 (p < 0.00001) and DR3 (p < 0.00001), DR7 (p < 0.01) alleles showed significant positive association with the disease.

Surface tension, glutathione content and redox ratio of the tracheal aspirate fluid of premature infants with IRDS

OBJECTIVE

Determination of the surface tension (ST), the total glutathione (GL) content and the ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) in the tracheal aspirate (TA) of newborn infants with IRDS.

METHODS

The ST of the TA was determined by monitoring the fluid level pulsated in a capillary glass tube by means of a digitalized videocomputerized picture analysis program, a technique developed in our laboratory. The concentrations of GSSG and total GL in the TA were determined enzymatically with glutathione reductase. All results of laboratory tests were referred to the total phospholipid (PL) concentration. Patients, Experimental Material: TA samples were collected from 32 intubated premature and newborn infants admitted to the NICU with IRDS during the first 2 weeks of their lives. Control samples were obtained from 11 children prior to elective surgery.

RESULTS

The ST relative to the PL content (surface tension index, STI) was significantly lower in the newborns with IRDS than in the control group, and the concentration of GSH in the TA was also markedly decreased in all IRDS infants studied. The concentration of GSSG and the ratio of GSSG to GSH were significantly higher in the severe cases and in those with an unfavourable prognosis. Surfactant treatment had a protective effect against oxidative stress, it induced a decrease in both the GSSG concentration and in the GL redox ratio (GSSG/GSH) in the TA. There was a close correlation between the GSH content and the STI value of the samples studied.

CONCLUSION

Oxidation and consequent depletion of GSH in the TA may be an aggravating factor in the development of the insufficient surface activity in intubated newborns with IRDS.

Oxidative stress induced by bloodless limb surgery on humans

Measure of oxidative stress were studied in blood samples from 10 patients undergoing bloodless lower limb surgery. Ischaemia induced a significant increase in plasma hypoxanthine concentration and xanthine oxidase activity both in the operated leg and in the systemic circulation. Five minutes after reperfusion, ratio of xanthine oxidase/total xanthine oxidase and dehydrogenase activities rose moderately, whereas at 20 min xanthine oxidase accounted for all xanthine oxidoreductase activity in the systemic circulation. A significant increase in blood glutathione redox ratio, enhanced oxidation of haemoglobin to methaemoglobin and rise in plasma haemoglobin concentration were present only in the operated limb. Thus, although the level of the potential free radical generators rose significantly both locally and in the systemic circulation, oxidative stress, as indicated by blood glutathione and erythrocyte injuries, remained limited to the reperfused leg.

The pathogenetic role of heme in pregnancy-induced hypertension-like disease in ewes

Toxicosis syndrome of fasting pregnant ewes has a close similarity to human preeclampsia (hypertension, albuminuria). The common etiological factor might be oxidative hemolysis and heme-induced endothelial damage. Ewes (5 starving, 5 control) at 130-135 gestational days with a 96-h fasting period followed by refeeding were used. Blood pressure, platelet count, electrolytes, kidney and liver function parameters, as well as plasma glucose, hemoglobin/heme, free thiol groups and Trolox equivalent antioxidant capacity, and plasma iron and ferritin levels were measured. Statistical significance was assessed using Student's t test (P < 0.05). Besides hypertension and renal disturbances, hemolysis, elevated liver enzymes and low platelet count, characteristic of human HELLP syndrome, were also present. In the first 24 h of glucose deprivation there was a significant rise in both the plasma hemoglobin/heme and indirect bilirubin concentrations. The antioxidant free thiol levels decreased significantly the next day, without any change in the total antioxidant capacity of the plasma. While the loss of calcium and magnesium levels related to the similarity to preeclampsia, reduced plasma iron concentrations referred to species differences in iron homeostasis. An oxidative stress causing hemolysis in a glucose-6-phosphate dehydrogenase-deficient animal model was proven by the loss of free thiols after glucose deprivation. The activation of the oxidative stress protein heme oxygenase was a signal of endothelial cell injury, the primary cause of pregnancy-induced hypertension.

[Prospective biochemical study of the antioxidant defense capacity in retinopathy of prematurity]

The study was carried out on 60 oxygen-treated premature infants weighed less than 2000 g (1529 +/- 302 g, x mean +/- S. D.) and on their mothers. Both the Retinopathy of Prematurity screening and the biochemical tests were started at the age of 6 weeks. According to our results, the signs of an acute oxidative stress could be seen in all 60 oxygen-treated prematures erythrocyte's glutathione redox system, independently of the presence of the retinopathy compared to prematures (n = 20) with the same gestational age but without oxygen therapy (1720 +/- 305 g, mean +/- S.D.). The concentrations of free sulfhydril groups in the plasma, and the blood selenium levels were significantly lower in the prematures suffering from moderate retinopathy (n = 5) than in the other oxygen-treated premature without retinopathy (n = 27) and with "any retinopathy" (n = 28) patients groups. The same tendency was seen in the mothers. Vitamin E treatment of "any retinopathy" infants seemed to have a positive effect against the development of Retinopathy of Prematurity. The close correlation found between the antioxidant capacity of the mothers and babies suggest that the supplementation of feeding with sulfur-containing amino acids (methionine, cysteine) during pregnancy would improve the antioxidant capacity of prematures. An antioxidant cocktail (selenium + vitamin E) given to the high-risk mothers (advanced age, smoking, pregnancy-induced hypertension) before delivery as suggested in literature might be useful in prevention of Retinopathy of Prematurity.

Oxidative stress and antioxidant defense mechanism in glomerular diseases

The changes in red blood cell (RBC) lipid peroxidation [measured via the malonyl dialdehyde (MDA) concentration], reduced (GSH), and oxidized glutathione (GSSG) levels, hemoglobin (Hb) oxidation and antioxidant enzyme [catalase (Cat), glutathione peroxidase, and superoxide dismutase (SOD)] activities were studied in 45 pediatric patients with various glomerular diseases [minimal change nephrotic syndrome (MCNS) in relapse or in remission, lupus nephropathy (SLE), poststreptococcal glomerulonephritis (APSGN), IgA nephropathy (IGA gn)], and in 20 adult patients with IGA gn and also in 15 pediatric and 14 adult controls. The in vitro effects of hydrogen peroxide [acetyl phenylhydrazine (APH) test] on the GSH and Hb metabolisms were likewise investigated. There was an increased oxidative stress in MCNS with relapse, IGA gn, SLE gn, and APSGN, which could be detected in the GSH and Hb oxidation and in the lipid peroxidation on the peripheral RBC-s. The RBC SOD and Cat activities were significantly lower in all patients than in the controls. The RBC GSSG level was significantly elevated in all patients, with the exception of MCNS in remission. This stimulated a compensatory GSH production in MCNS with relapse and in IGA gn, but not in SLE or APSGN. The regeneration of GSH from GSSG was reduced in MCNS with relapse, SLE, and IGA gn, but not in APSGN. In remission, the GSH-GSSG redox system normalizes, but in vitro the APH test stimulates an intensive Hb oxidation. In conclusion, there is a correlation between the presence of active glomerular disease and the evidence of oxidative changes in the various parameters measured in peripheral RBCs.

Serological survey on the prevalence of chicken anaemia virus infection in Hungarian chicken flocks

A serological survey on the prevalence of chicken anaemia virus (CAV) infection was performed by using the indirect immunofluorescence (IF) and the virus neutralization (VN) tests in commercial Hungarian chicken populations. By the indirect IF test, a total of 846 serum samples from 13 meat-type parent flocks of two breeds were investigated between 10 and 62 weeks of age. All flocks were found to be positive for anti-CAV antibodies, and the rates of antibody-positive birds among flocks ranged from 40 to 93.3% and with an average of 73.3%. From nine 1-day- to 9-week-old progeny broiler flocks, 96 serum samples were tested. In the 3 flocks, sampled at the hatchery, 75 to 100% (average 86.4%) of the 22 tested birds were antibody positive. From the 6 flocks, tested between 4 to 9 weeks of age, 3 were antibody negative at 4 and 5 weeks of age, whereas in the 3 remaining 6- to 9-week-old flocks 10 to 20% (average 13.5%) of the birds were antibody positive. In egg-laying parent flocks of 14 and 35 weeks old, 54.4 and 71.7% of the tested 79 and 46 birds had antibodies to CAV, respectively. By the VN test, a total of 670 serum samples from 9 meat-type parent flocks aged between 11 and 37 weeks were investigated. The rate of antibody positivity in flocks was always over 80% and averaged 90.9%. From 7 progeny broiler flocks, 261 serum samples were tested between one day and 7 weeks of age, and the rates of seropositivity in flocks were between 93.3 to 100% and averaged 96.9%. In an egg-laying parent flock, 89.2% of the tested 102 birds had neutralizing antibodies to CAV at 35 weeks old. It was concluded that CAV is widespread in Hungarian commercial chicken populations. Though, according to simultaneous examination of 195 flock sera, the VN test revealed 11.3% more antibody-positive birds, the indirect IF test was found suitable for serological surveys at flock(s) level, provided that sufficient numbers of individual chicks were tested.

Blood glutathione redox ratio as a parameter of oxidative stress in premature infants with IRDS

Oxygen toxicity is thought to play an important pathogenic role in several neonatal diseases, including idiopathic respiratory distress syndrome (IRDS). Therefore, the development of a reliable measure of the actual oxidative stress status of patients would be of great clinical significance. In order to obtain information about the oxidative stress during the first week of life in premature infants with IRDS, the blood concentrations of oxidized and reduced glutathione, as well as their molar ratios, were determined by a highly sensitive, specific enzymic assay. The fractional inspired oxygen concentrations needed to maintain adequate arterial oxygen tension and the arterio-alveolar oxygen ratios were chosen as parameters indicating the severity of illness in premature infants at a given time. There was a highly significant positive correlation between the glutathione redox ratios and the fractional inspired oxygen concentrations. A maturity-related difference was also found; the oxidized glutathione concentrations were the highest in the least mature infants, accompanied by a pronounced compensatory rise in the reduced glutathione concentrations as well. A significant negative correlation was found between the arterio-alveolar oxygen ratio and the glutathione redox ratio: i.e., an improvement in oxygenation was accompanied by a decrease in the glutathione redox ratio. The efficient recycling of reduced glutathione in erythrocytes providing antioxidant protection for premature infants, permits the use of the blood glutathione redox ratio as a noninvasive measure of in vivo oxidative stress.

Oxidative damage of red blood cells in haemolytic uraemic syndrome

Changes in red blood cell (RBC) lipid peroxidation [measured by malonyl dialdehyde (MDA) concentration], glutathione (GSH) metabolism, antioxidant enzyme activities (catalase, superoxide dismutase, glutathione peroxidase) and haemoglobin (Hb) metabolites (metHb, carboxy Hb) were studied in six children with post-enteropathic (D+) haemolytic uraemic syndrome (HUS) and ten controls. The in vitro effect of hydrogen peroxide [acetylphenylhydrazine (APH) test] on GSH and Hb metabolism was also investigated. MDA levels were significantly higher and the antioxidant enzyme activities were lower in HUS patients than in the controls (P < 0.01). The oxidised glutathione concentration was significantly higher in the patients than in the control children (26.3 +/- 12.6 vs. 10.9 +/- 1.8 nmol/g Hb. Percentage values of carboxy Hb and metHb were also higher in HUS (P < 0.01). Incubation of RBC with APH induced a more pronounced decrease in the concentration of GSH (P < 0.001) and a significant increase (P < 0.01) in the level of metHb and carboxy Hb in the HUS patients. This suggests that there is reduced RBC GSH stability in HUS. Utilisation of GSH and antioxidant enzymes leads to increased Hb oxidation and haemolysis. The oxidative damage may have an important role in the pathogenesis of haemolytic anaemia in HUS.

[Retrospective biochemical study of the preventive property of antioxidants in retinopathy of prematurity]

Oxygen radical injury may be one of the factors leading to Retinopathy of Prematurity. It occurs when the body's natural antioxidant capacity is overwhelmed by the free oxygen radicals produced during the perinatal period. Supposing, that premature infants may have defects in their antioxidant systems which can be detected later, even in childhood, a retrospective study of 36 patients of different ages (born prematurely) suffering from different stages of Retinopathy of Prematurity was carried out. According to our results, the signs of an acute oxidative stress could only be seen in the 3 month-old patients' erythrocyte glutathione redox system which was independent of the clinical severity of retinopathy. However, following an in vitro oxidative stress an increased susceptibility of erythrocytes was found in all our patient groups, which means, that the ratio of residual and original amounts of reduced glutathione was decreased and the amount of oxidated derivates of haemoglobin was increased. As selenium is an integral part of glutathione peroxidase enzyme, the very low selenium levels measured in all of our patient groups indicate a reduced glutathione peroxidase activity. The present study suggests, that selenium depletion even in Hungary might play an important role in the pathogenesis of Retinopathy of Prematurity.

The effect of erythropoietin on the cellular defence mechanism of red blood cells in children with chronic renal failure

The glutathione redox system, haemoglobin (Hb) oxidation, the activity of antioxidant enzymes and the lipid peroxidation product malonyl dialdehyde (MDA) were studied in red blood cells (RBCs) during administration of recombinant human erythropoietin (rhEPO) over 12 weeks in ten children maintained on haemodialysis. A rapid increase in the reticulocyte count was accompanied by a slower rise in total Hb concentration. The mean level of oxidized glutathione (GSSG) increased from 13.2 +/- 5.3 nmol/g Hb to 56.7 +/- 15.8 nmol/g Hb 4 weeks after the start of rhEPO (P < 0.001), followed by a fall to the basal value. Reduced glutathione (GSH) levels showed a smaller though constant elevation during rhEPO therapy (P < 0.001). Before rhEPO treatment, incubation of RBCs for 1 h with acetylphenylhydrazine induced a decrease in GSH concentration compared with controls (P < 0.001), which became more pronounced in the first few weeks of rhEPO therapy (P < 0.001). In addition, the percentage of Hb derivatives (metHb and haemichrome) increased in the first 4 weeks of rhEPO therapy (P < 0.001). Although there was no significant difference between the values obtained preEPO and during EPO treatment, MDA levels were continuously higher and superoxide dismutase, catalase and glutathione peroxidase concentrations were lower than in the controls (P < 0.001). These results are compatible with oxidative damage to the RBCs in the early period of rhEPO therapy in children with end-stage renal failure. The GSH-GSSG system, as an important cellular defence mechanism of the RBCs, appears to be severely affected.

Examination of the role of oxygen free radicals in bronchial asthma in childhood

The antioxidant enzyme activities, the lipid peroxidation level, the parameters of glutathione metabolism, and the proportion of haemoglobin oxidation products were determined during the symptom-free period of childhood bronchial asthma. A decreased catalase activity and a significantly reduced glutathione instability were demonstrated as compared to the controls. The results indicate that antioxidant protection of the haemoglobin molecule in asthmatic children is considerably decreased.

Erythrocyte defense mechanisms against free oxygen radicals in haemodialysed uraemic children

Changes in erythrocyte lipid peroxidation (measured as the concentration of malonyl dialdehyde), glutathione metabolism, antioxidant enzyme activities (glutathione peroxidase, catalase, and superoxide dismutase), the oxidized products of haemoglobin (Hb), and hydrogen peroxide (H2O2)-induced haemolysis were studied in six children with chronic renal failure treated with serial acetate and bicarbonate haemodialysis (HD). Ten age- and sex-matched children acted as controls. Malonyl dialdehyde levels were significantly higher and antioxidant enzyme activities lower in uraemic red blood cells (RBCs) compared with controls (P less than 0.05). Incubation of RBCs for 1 h with acetylphenylhydrazine induced a decrease in the concentration of reduced glutathione (P less than 0.001) and an increase in the level of oxidized products of Hb (P less than 0.001), but only in the uraemic patients. The H2O2 haemolysis test revealed a mild (n = 3) to increased (n = 3) haemolysis in the uraemic RBCs. Oxidative haemolysis is probably a multifactorial process in uraemic patients, and may be an important risk factor in HD therapy.

De novo complex chromosomal rearrangement in a woman with recurrent spontaneous abortion and one healthy daughter

Although rare, complex chromosomal rearrangements have been reported in the literature. The result is multiple congenital malformations in the offspring and recurrent spontaneous abortion. Chromosome 7 is usually involved, but in our patient chromosome 18 was involved.

[Selenium levels in erythrocytes of children with celiac disease]

Selenium is the component of the glutationperoxidase one of the most important enzymes in the antioxidant protection of the organism. In preliminary studies the authors found in celiac children increased sensitivity to oxidative stress and biochemical changes referring to decreased activity of glutationperoxidase enzyme. Therefore the selenium content of washed erythrocytes has been determined with fluorimetry in 24 celiac children kept on gluten containing diet and 25 on gluten-free diet. In gluten loading the selenium level was significantly lower than in the healthy control group. The selenium value rose at a small degree in the erythrocytes of celiac children kept on gluten-free diet but did not reach the lower limit of the physiological value. On the basis of these results the malabsorption of selenium was found to play also an important role in the decreased protecting capacity against oxidative stress effects in celiac diseases of childhood. The necessity of supplementing the trace element is raised.

Effect of allopurinol treatment in premature infants with idiopathic respiratory distress syndrome

A randomized prospective study of the effectiveness of allopurinol (Ap), a potent and specific inhibitor of the enzyme xanthine oxidase, was performed in premature infants endangered by hypoxia. The drug was given at a dose of 20 mg/kg/day orally for 3 days. In the Ap-treated group the expected decrease in the serum concentration and urinary excretion of uric acid was accompanied by a decrease in the mortality rate of infants with idiopathic respiratory distress syndrome. In these patients a concomitant improvements in renal function, as indicated by an increased urinary flow rate and creatinine output, was also obvious. It is suggested that the observed beneficial effect is due to the specific inhibition of xanthine oxidase associated with Ap therapy leading to reduced generation of superoxide radicals and decreased urinary loss of purine.

Serum and urinary arginine-esterase activity in paediatric kidney diseases

Serum and urinary kallikrein activities were determined from the arginine-esterase activities in various groups of kidney diseases and were compared with urinary beta-glucuronidase excretion, urinary output, urinary protein content and creatinine clearance. Serum arginine-esterase activity was significantly augmented in the active stage of diffuse renal diseases but was not related to the severity of parenchymal damage. The values improved during remission; the enzyme activity in chronic uraemic patient was as low as in the control sera. There was a positive correlation between urinary output and serum arginine-esterase activity, and consequently serum kallikrein might have an enhancing effect on diuresis.