Fat-soluble vitamins in breast-fed preterm and term infants.

OBJECTIVE: To examine the supply and status of fat-soluble vitamins in very low birth weight (VLBW) infants compared to a reference group of normal birth weight (NBW) infants. DESIGN: A longitudinal study of VLBW infants in the early neonatal period. Blood samples were drawn at 1 week of age and at discharge from hospital. Plasma was analyzed for the fat-soluble vitamins: retinol, 25-OH-vitamin D, alpha-tocopherol and phylloquinone (vitamin K(1)) using high-performance liquid chromatography. SUBJECTS: A total of 40 VLBW infants were included in the study. A reference group of 33 NBW infants was randomly selected from one of our previous studies. RESULTS: The VLBW infants received fortified human milk, and daily oral vitamin supplement (Multibionta). In VLBW infants, plasma retinol concentrations decreased and plasma 25-OH-vitamin D increased during the study period. VLBW infants had significantly lower plasma retinol (0.3 vs 0.7 mu M) and higher plasma 25-OH-vitamin D (166 vs 25 nM) at discharge compared to NBW infants. Plasma phylloquinone concentration in VLBW infants was very high (53 ng/ml) at one week of age, especially in the youngest infants (192 ng/ml), but decreased rapidly during the study period resulting in low/normal plasma concentrations (0.9 ng/ml) at discharge. CONCLUSIONS: We observed alterations in plasma concentration of retinol and 25-OH-vitamin D in VLBW infants in the early neonatal period, resulting in marked differences between VLBW at discharge and NBW. Further trials are needed to evaluate whether changes in vitamin supplementation may improve clinical outcome in VLBW infants.

Beta-oxidation of medium chain (C8-C14) fatty acids studied in isolated liver cells.

The beta-oxidation and esterification of medium-chain fatty acids were studied in hepatocytes from fasted, fed and fructose-refed rats. The beta-oxidation of lauric acid (12:0) was less inhibited by fructose refeeding and by (+)-decanoyl-carnitine than the oxidation of oleic acid was, suggesting a peroxisomal beta-oxidation of lauric acid. Little lauric acid was esterified in triacylglycerol fraction, except at high substrate concentrations or in the fructose-refed state. With [1-14C]myristic acid (14:0), [1-14C]lauric acid (12:0), [1-14C]octanoic acid (8:0) and [2-14C]adrenic acid (22:4(n - 6] as substrate for hepatocytes from carbohydrate-refed rats, a large fraction of the 14C-labelled esterified fatty acids consisted of newly synthesized palmitic acid (16:0), stearic acid (18:0) and oleic acid (18:1) while intact [1-14C]oleic acid substrate was esterified directly. With [9,10-3H]myristic acid as the substrate, small amounts of shortened 3H-labelled beta-oxidation intermediates were found. With [U-14C]palmitic acid, no shortened fatty acids were detected. It was concluded that when the mitochondrial fatty acid oxidation is down-regulated such as in the carbohydrate-refed state, medium-chain fatty acids can partly be retailored to long-chain fatty acids by peroxisomal beta-oxidation followed by synthesis of C16 and C16 fatty acids which can then stored as triacylglycerol.

The Zellweger syndrome: deficient conversion of docosahexaenoic acid (22:6(n-3)) to eicosapentaenoic acid (20:5(n-3)) and normal delta 4-desaturase activity in cultured skin fibroblasts.

The metabolism of docosahexaenoic acid (22:6(n-3)) and adrenic acid (22:4(n-6)) was studied in cultured fibroblasts from patients with the Zellweger syndrome, X-linked adrenoleukodystrophy (X-ALD) and normal controls. It was shown that [4,5- 3H]22:6(n-3) is retroconverted to labelled eicosapentaenoic acid (20:5(n-3)) in normal and X-ALD fibroblasts, while this conversion is deficient in Zellweger fibroblasts. [U- 14C]Eicosapentaenoic acid (20:5(n-3)) is elongated to docosapentaenoic acid (22:5(n-3)) in all three cell lines. With [U- 14C]20:5(n-3) as the substrate, shorter fatty acids were not detected. With [4,5- 3H]22:6(n-3) as the substrate, labelled fatty acids were esterified in the phospholipid- and triacylglycerol-fraction to approximately the same extent in all three cell lines. [2- 14C]Adrenic acid (22:4(n-6)) was desaturated to 22:5(n-6) and elongated to 24:4(n-6) in all three cell lines and to the largest extent in the Zellweger fibroblasts. This agrees with the view that the delta 4-desaturase is not a peroxisomal enzyme. The observation that the retroconversion of 22:6(n-3) to 20:5(n-3) is deficient in Zellweger fibroblasts strongly suggest that the beta-oxidation step in the retroconversion is a peroxisomal function. Peroxisomal very-long-chain (lignoceroyl) CoA ligase is probably not required for the activation of 22:6(n-3), since the retroconversion to 20:5(n-3) is normal in X-ALD fibroblasts.

Effects of dietary purified eicosapentaenoic acid (20:5 (n-3)) and docosahexaenoic acid (22:6(n-3)) on fatty acid desaturation and oxidation in isolated rat liver cells.

The effects of dietary supplementation of eicosapentaenoic acid (20:5(n-3), EPA) and docosahexaenoic acid (22:6(n-3), DHA) on the metabolism of polyunsaturated fatty acids were studied in isolated rat liver cells. Both pure EPA and pure DHA and a mixture of the two n-3 fatty acids in different doses were used. The supplementation of moderate amounts of n-3 fatty acids suppressed the activity of delta 6-desaturase (50%) and to a smaller extent of the delta 5-desaturase (60-70%) compared to controls. When higher doses of dietary purified EPA and DHA were used, this inhibitory effect on the delta 6- and delta 5-desaturase activities disappeared. The delta 4-desaturase activity seemed to be unaffected by the feeding conditions used. The supplementation of the n-3 fatty acids in the diet at all dose levels used increased the beta-oxidation of all the polyunsaturated fatty acids, especially of linoleic acid, linolenic acid and eicosapentaenoic acid. The results suggest an increase both in peroxisomal and mitochondrial beta-oxidation. The peroxisomal beta-oxidation of n-3 fatty acids seemed to be particularly increased.

Effects of clofibrate feeding on essential fatty acid desaturation and oxidation in isolated rat liver cells.

The effects of clofibrate feeding on the metabolism of polyunsaturated fatty acids were studied in isolated rat hepatocytes. Administration of clofibrate stimulated the oxidation and particularly the peroxisomal beta-oxidation of all the fatty acids used. The increase in oxidation products was markedly higher when n-3 fatty acids were used as substrate, indicating that peroxisomes contribute more to the oxidation of n-3 than n-6 fatty acids. The whole increase in oxidation could be accounted for by a corresponding decrease in acylation in triacylglycerol while the esterification in phospholipids remained unchanged. A marked stimulation of the amounts of newly synthesized C16 and C18 fatty acids recovered, was observed when 18:2(n-6), 20:3(n-6), 18:3 (n-3) and 20:5(n-3), but not when 20:4(n-6) and 22:4(n-6) were used as substrate. This agrees with the view that extra-mitochondrial acetyl-CoA produced from peroxisomal beta-oxidation is more easily used for fatty acid new synthesis than acetyl-CoA from mitochondrial beta-oxidation. The delta 6 and delta 5 desaturase activities were distinctly higher in cells from clofibrate fed rats indicating a stimulating effect.

Peroxisomal retroconversion of docosahexaenoic acid (22:6(n-3)) to eicosapentaenoic acid (20:5(n-3)) studied in isolated rat liver cells.

Retroconversion of docosahexaenoic acid (DHA, 22:6(n-3)) to eicosapentaenoic acid (EPA, 20:5(n-3)) was studied in isolated rat liver cells. 20% of the substrate was retroconverted to EPA in control cells by one cycle of beta-oxidation probably with delta 4 enoyl CoA reductase and delta 3, delta 2 enoyl CoA isomerase as auxiliary enzymes. This conversion was not stimulated by (-)-carnitine and was not inhibited by the addition of (+)-decanoylcarnitine. In hepatocytes from fasted rats little EPA was formed from DHA. These results strongly suggest that the retroconversion of DHA to EPA is a peroxisomal function. Retroconverted EPA, produced from DHA was rapidly incorporated in triacylglycerol, the phosphatidylcholine and phosphatidyletanolamine fractions. During longer incubation time EPA was partly removed from the phospholipid fractions, chain-elongated to 22:5(n-3) and incorporated in the triacylglycerol fraction.

Omega-oxidation of fatty acids studied in isolated liver cells.

The omega- and beta-oxidation of medium- and long-chain fatty acids (C10-C18) were studied in hepatocytes from fasted, fed and clofibrate-fed rats. The omega-oxidation systems were most active with lauric acid (12:0) and decanoic acid (10:0) as substrates and there was decreasing activity with chain lengths from 14 to 18 carbon atoms. In fed rats no omega-oxidation of fatty acids was detected unless the mitochondrial beta-oxidation was inhibited. In fasted rats the omega-oxidation was less than 2% and preincubation with (+)-decanoylcarnitine increased the omega-oxidation to 15% of the total fatty acid oxidation. Clofibrate feeding did not increase the omega-oxidation in isolated hepatocytes. Inhibition of the alcohol dehydrogenase with 4-methylpyrazole inhibited both the oxidation of omega-hydroxylated fatty acid and the initial hydroxylation of lauric acid to dicarboxylic acid, suggesting the importance of the alcohol dehydrogenase in the omega-oxidation of fatty acids. 95% of the dicarboxylic acids and 80% of the hydroxy-fatty acids were excreted from the cells in the incubations with decanoic acid (10:0). No chain-shortened dicarboxylic acids were detected with [1-14C]decanoic- or [1-14C]lauric acid as substrate, while small amounts C10 and C12 dicarboxylic acids were observed in incubations with [1-14C]myristic acid (14:0).

Adrenoleukodystrophy. The chain shortening of erucic acid (22:1(n-9)) and adrenic acid (22:4(n-6)) is deficient in neonatal adrenoleukodystrophy and normal in X-linked adrenoleukodistrophy skin fibroblasts.

The metabolism of long chain unsaturated fatty acids was studied in cultured fibroblasts from patients with X-linked adrenoleukodystrophy (ALD) and with neonatal ALD. By using [14-14C] erucic acid (22:1(n-9)) as substrate it was shown that the peroxisomal beta-oxidation, measured as chain shortening, was impaired in cells from patients with neonatal ALD. The beta-oxidation of adrenic acid (22:4(n-6)), measured as acid-soluble products, was also reduced in the neonatal ALD cells. The peroxisomal beta-oxidation of [14-14C]erucic acid (22:1(n-9)) and [2-14C]adrenic acid (22:4(n-6)) was normal in cells from X-ALD patients. The beta-oxidation, esterification and chain elongation of [1-14C]arachidonic acid (20:4(n-6)) and [1-14C]eicosapentaenoic acid (20:5(n-3)) was normal in both X-linked ALD and in neonatal ALD. Previous studies suggest that the activation of very long chain fatty acids by a lignoceryl (24:0)-CoA ligase is deficient in X-linked ALD, while the peroxisomal beta-oxidation enzymes are deficient in neonatal ALD. The present results suggest that the peroxisomal very long-chain acyl-CoA ligase is not required for activation of unsaturated C20 and C22 fatty acids and that these fatty acids can be efficiently activated by the long chain acyl-(palmityl)-CoA ligase.

The effect of dietary alpha-bromopalmitate on blood lipids in the rat.

When alpha-bromopalmitate was fed to rats for 9-30 days, the level of serum triacylglycerol increased up to 2-fold over the concentration of controls. alpha-Bromopalmitate treatment had no effect on concentration of complex lipids in liver, while the triacylglycerol level in heart was significantly enhanced. From metabolic studies using isolated hepatocytes and liver microsomes, it is suggested that the increased serum triacylglycerol level after alpha-bromopalmitate feeding is mainly due to reduced fatty acid oxidation in both liver and peripheral tissues, and to a lesser extent, to inhibited fatty acid uptake and esterification.

The effect of dietary N-3 fatty acids on osmotic fragility and membrane fluidity of human erythrocytes.

Sixteen healthy females were randomly assigned to receive fish oil or corn oil double blind in a 28 days intervention period. Osmotic fragility of erythrocytes was decreased in the fish-oil supplemented group and not affected in the corn-oil group. The decrease in osmotic fragility was maximal after 14 days and approached the pre-intervention level after 24 and 28 days of n-3 supplementation. No change was observed in erythrocyte membrane fluidity in either of the groups. The level of n-3 fatty acids increased significantly in erythrocytes from the fish oil supplemented subjects, mainly at the expense of linoleic acid (18:2, n-6) and oleic acid (18:1). No significant change was seen in the relative amount of arachidonic acid (20:4,n-6) or in the phospholipid/cholesterol ratio in erythrocytes, while the ratio between the sum of phoshatidylcholine and sphingomyeline/phosphatidylethanolamine (PC+SM/PE) increased during the intervention period. This study does not verify the hypothesis of a relationship between osmotic fragility and membrane fluidity. It is concluded that increased level of n-3 fatty acids in erythrocyte membranes decreases osmotic fragility, and that this effect is counteracted by increased PC+SM/PE ratio.

Regulation of the metabolism of polyunsaturated fatty acids.

The object of the present work has been to assess some aspects of the control of the metabolism of polyunsaturated fatty acids. In these studies we have used isolated cells; hepatocytes and cardiac myocytes from rat, and lymphocytes and fibroblasts from humans. Attention has focused on the importance of dietary and hormonal factors which can exert an effect shortly after activation of fatty acid, and thus may determine whether the fatty acid will be desaturated, chain-elongated, directly esterified or oxidized. Both the short-term and long-term regulation excerted by dietary fat have been studied in both rat and human. Profound sex-differences exist in fatty acid esterification, oxidation and fatty acid composition in lipoproteins. It is suggested that these differences, at least in part are due to a different content of intracellular fatty acid binding proteins in female and male liver. The peroxisomal retroconversion of C22-unsaturated fatty acids to their C20-homologues is probably involved in the regulation of fatty acid composition in membrane phospholipids, being a sort of "overflow valve". In several somewhat different diseases the patients have no peroxisomes or their peroxisomes are defective. In these peroxisomal diseases the beta-oxidation of very long-chain fatty acids is deficient. In this present work we show that fibroblast from patients with the peroxisomal diseases, Zellweger disease, X-linked adrenoleukodystrophy and neonatal adrenoleukodystrophy differ in their ability to shorten C22-fatty acids.

[Natural surfactant in routine treatment of neonatal respiratory distress syndrome. Experiences from two central hospitals]. / Naturlig surfaktant som rutinebehandling av neonatalt åndenødssyndrom. Erfaringer fra to sentralsykehus.

Regular use of surfactant in the treatment of respiratory distress syndrome started in Norwegian neonatal intensive care units in 1992. The authors present the results for the first 70 babies with respiratory distress syndrome who were treated with natural surfactant from 1991 to 1994 at two level II hospitals. Median time of administration dropped from eight hours after birth in 1991 to three hours in 1994. Treatment soon after birth leads to a greater reduction in oxygen requirement. 12 children died, all of them very immature after complicated pregnancies. The total mortality in babies with a birth weight of less than 1,500 grams was 7%. The incidence of severe bronchopulmonary dysplasia was markedly reduced and the total number of days on a ventilator was reduced by 50%. Use of surfactant was not associated with more complications. Severe respiratory distress syndrome should be prevented with antenatal steroids, and treated early postnatally with natural surfactant.

[Surfactant treatment of acute pulmonary failure. Other indications than neonatal distress syndrome]. / Surfaktantbehandling ved akutt lungesvikt. Andre indikasjoner enn neonatalt åndenødssyndrom.

In 1959 Avery and Mead suggested internationally that respiratory failure in premature infants is due to lack of surfactant. Surfactant is a phospholipid protein complex that is synthesised and stored in alveolar type II pneumocytes in the lungs. The main function of surfactant is to reduce surface tension in the lungs and make respiratory effort easier. Since 1959 much of scientific work has been done in this field, and there is now increasing evidence to support the theory that surfactant is important for normal lung function. Therefore surfactant insufficiency plays a major role in acute respiratory failure of any etiology. In this paper we focus on other possible indications for surfactant replacement therapy, and describe a patient with meconium aspiration syndrome which was treated successfully with exogenous natural surfactant.

The decrease in osmotic fragility of erythrocytes during supplementation with n-3 fatty acids is a transient phenomenon.

In order to study the effect of dietary n-3 fatty acids on osmotic fragility of human erythrocytes, 11 healthy subjects were given a supplement of 6 g day-1 of an oil containing 50% n-3 fatty acids for either 14 days or 34 days. Fourteen days after start the osmotic fragility was decreased by 60-80% (buffer-salt concentration 0.41%), and the level of n-3 fatty acids in membrane phospholipids was increased by approximately 60%. The decrease in fragility was less marked after 24 days and almost at the pre-supplementation level after 34 days. There was no correlation between changes in fragility and in the fatty acid pattern of membrane phospholipids of the erythrocytes. The changes induced in fatty acid composition of phospholipids did not affect membrane fluidity. It is concluded that factors other than the nature of fatty acids in membranes may be involved in modifying osmotic fragility, and that there is no correlation between membrane fragility and membrane fluidity.

[Intrauterine nutrition]. / Intrauterin ernaering.

Foetal or intrauterine nutrition is a subject of increasing interest. There are two main reasons for this. The first one is the observation that being born small for gestational age is associated with increased risk of cardiovascular disease and diabetes later in life. The second one is the discovery that nutritional factors directly influence activity of genes. If nutritional inadequacies in the foetal period permanently alter the expression of genes, the individual's susceptibility to perinatal complications and diseases later in life may be altered. The main causes of intrauterine malnutrition are poor maternal diet, placental insufficiency, and impaired foetal usage of nutrients. The consequences of foetal malnutrition may include intrauterine growth retardation, congenital malformation, a variety of neurological dysfunctions, susceptibility to birth asphyxia, and diseases later in life; all of these are important determinants of health throughout life.

C-reactive protein as an indicator of infection in the immunosuppressed child.

C-reactive protein (CRP) concentrations were determined in a prospective fashion in 50 children with malignant disease. In 35 children with active and aggressive disease, but without signs of infection, no significant increase in CRP was detected. Neither did aggressive cytostatic therapy (70 courses) in non-infected children result in an increase. In bacteriologically proven, and in clinical sepsis-suspected cases, CRP values increased in all cases to levels above 100 mg/l (normal values less than 5 mg/l). Effective antibiotic therapy resulted in a prompt decline in CRP. Viral infections resulted in a much smaller increase. We conclude that serial measurements of CRP in these immunosuppressed children are of great help in monitoring infections and defining the group that needs antibiotic therapy. The measurement is also a good indicator of the effectiveness of the antibiotic therapy chosen.

Dietary n-3 fatty acids and children with hyperlipidaemia.

A review of the literature shows that no studies on children with primary genetic lipid disorders have been published. Case reports are presented indicating that hyperlipidaemias presenting in children--both familial hypercholestrolaemia and disorders with secondary hyperlipidaemia (triglycerides) may benefit of the intake of n-3 fatty acids.

Dietary n-6 fatty acids inhibit the incorporation of dietary n-3 fatty acids in thrombocyte and serum phospholipids in humans: a controlled dietetic study.

The effect of a high dietary intake of n-6 fatty acids (36 g daily) vs a low intake (4-6 g daily) on the incorporation of fatty acids from a dietary supplementation of n-3 fatty acids (6 g daily) was studied for 8 weeks in 15 healthy, normolipaemic volunteers. The importance of a high (43.6) vs a low (20.6) energy percentage from fat was also investigated in the participants on a low n-6 intake. Fatty acid analyses of serum and thrombocyte phospholipids showed a marked increase in docosahexaenoic acid (22:6 (n-3), DHA) and especially eicosapentaenoic acid (20:5 (n-3), EPA) in both the high and low n-6 groups after 14 days, but the changes were significantly greater in the low n-6 diet groups. Changes of the ratio between EPA and arachidonic acid (20:4 (n-6), AA) in phospholipids followed an identical pattern in serum and thrombocytes. This indicates that thrombocytes are influenced by the fatty acid composition in serum. The results showed that incorporation of n-3 fatty acids in phospholipids was reduced by a high intake of dietary n-6 fatty acids in the cells and lipid fractions studied. The observed effect of dietary n-6 fatty acids was independent of the energy percentage provided by dietary fat. In order to obtain an optimal effect of n-3 supplementation, the intake of linoleic acid has to be considered and kept at a low level. The serum content of cholesterol was unaffected, but the concentration of triacylglycerol was reduced during the supplementation period.

[Neonatal respiratory distress syndrome treated with a natural surfactant. The Norwegian Curosurf study]. / Neonatalt åndenødssyndrom behandlet med naturlig surfaktant. Den norske Curosurfstudien.

43 Norwegian premature infants with respiratory distress syndrome were randomized to receive either a high dose (initial dose 200 mg/kg) or a low dose (initial dose 100 mg/kg) of natural porcine surfactant (Curosurf). In the high dose group, up to five doses of surfactant could be given compared with three in the low dose group. In the high dose group, oxygen requirement was significantly lower during the first 36 hours after surfactant was administered than the requirement in the low dose group. There was no difference in outcome between the high and low dose groups. Outcome was poor for babies with birthweight < 750 gram or gestational age < 26 weeks, in spite of an initial favourable surfactant response in several of them. We conclude that the initial dose of Curosurf should be 100 mg/kg and two more doses can be given if necessary.

Leukemic blasts with markers of four cell lineages in Down's syndrome ("megakaryoblastic leukemia").

Among 16 patients with Down's syndrome (DS) and acute leukemia admitted to our department during a ten year period, 6 were diagnosed as acute megakaryoblastic leukemia (AMkL). The diagnosis was based on clinical and hematologic criteria, confirmed in three patients with the use of monoclonal antibodies (MoAb) specific for megakaryocytic antigens. In these three, and in a fourth patient, the leukemic blasts were positive for other myeloid, lymphoid and erythroid markers in MoAb testing. We suggest that AMkL in DS is a mixed lineage leukemia with blasts presenting a variety of cell surface antigens, indicating origin from an early progenitor cell with the capability of megakaryocytic differentiation. Of the 6 patients with AMkL, 4 treated with standard AML protocols are in complete continuing remission (CCR) with observation periods from 57+ to 148+ months.