Large neutral amino acids block phenylalanine transport into brain tissue in patients with phenylketonuria.

Large neutral amino acids (LNAAs), including phenylalanine (Phe), compete for transport across the blood-brain barrier (BBB) via the L-type amino acid carrier. Accordingly, elevated plasma Phe impairs brain uptake of other LNAAs in patients with phenylketonuria (PKU). Direct effects of elevated brain Phe and depleted LNAAs are probably major causes for disturbed brain development and function in PKU. Competition for the carrier might conversely be put to use to lower Phe influx when the plasma concentrations of all other LNAAs are increased. This hypothesis was tested by measuring brain Phe in patients with PKU by quantitative 1H magnetic resonance spectroscopy during an oral Phe challenge with and without additional supplementation with all other LNAAs. Baseline plasma Phe was approximately 1,000 micromol/l and brain Phe was approximately 250 micromol/l in both series. Without LNAA supplementation, brain Phe increased to approximately 400 micromol/l after the oral Phe load. Electroencephalogram (EEG) spectral analysis revealed acutely disturbed brain activity. With concurrent LNAA supplementation, Phe influx was completely blocked and there was no slowing of EEG activity. These results are relevant for further characterization of the LNAA carrier and of the pathophysiology underlying brain dysfunction in PKU and for treatment of patients with PKU, as brain function might be improved by continued LNAA supplementation.

Glutathione and association antioxidant systems in protein energy malnutrition: results of a study in Nigeria.

Marasmus and kwashiorkor are manifestations of protein energy malnutrition. The pathophysiology of these disorders is poorly understood. We studied a number of blood antioxidants [glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR) and its cofactor flavin adenine dinucleotide (FAD), the tripeptide glutathione as the major nonprotein thiol], serum albumin, and retinol-binding protein in 12 children suffering from kwashiorkor with all classical symptoms, in 13 patients with clinically severe marasmus, in 19 marasmic but active children, and in 23 controls. Significant changes were observed for erythrocyte glutathione and correspondingly for nonprotein thiols in whole blood (0.72 +/- 0.29 mM thiols in controls, 0.50 +/- 0.22 mM in marasmus, 0.35 +/- 0.23 mM in severe marasmus, and 0.22 +/- 0.13 mM in kwashiorkor). These differences were paralleled by a decrease in serum albumin concentration so that the molar ratio of nonprotein thiols/albumin had an average value of approximately 1.5 in all groups. The erythrocyte glutathione-reducing system, represented by G6PDH and glutathione reductase, showed only slight differences among the four groups of children; the supposition that kwashiorkor occurs predominantly in children with aberrant G6PDH could not be substantiated. Unexpectedly, erythrocyte FAD, an index of riboflavin status, was normal in most malnourished patients. Discussed is the prospect of administering glutathione in kwashiorkor patients.

Fatty acid composition of mature human milk in Germany.

An improved gas-chromatographic method with high resolution, sensitivity, and precision was used for analyzing the fatty acid composition of human milk lipids. In 24-h collections of mature hindmilk of 15 German women, 42 different fatty acids could be separated and quantified. Among the saturated fatty acids (median sum 42.76%, wt/wt), six odd-chain fatty acids accounted for 1.16%. Cis monounsaturated acids represented 37.98%. Trans fatty acids, which may have untoward effects on the recipient infant, contributed 4.40% with seven isomers. The polyunsaturated fatty acid (PUFA) fraction (13.82%) included 10 long-chain PUFAs (LCPs; 1.66%). The content of the physiologically important LCPs in milk lipids did not correlate with their parent fatty acids (ie, linoleic and alpha-linolenic acids) but there was a significant correlation between the sum of omega-3 and omega-6 LCPs suggesting interindividual differences in the capacity for secretion of milk-lipid LCPs between mothers.

Glutaryl-coenzyme A dehydrogenase deficiency: a distinct encephalopathy.

Clinical course, diagnostic and therapeutic management, and neurodevelopmental outcome were evaluated in 11 patients with glutaryl-coenzyme A dehydrogenase deficiency. In 9 patients macrocephalus was present at or shortly after birth and preceded the neurological disease. In 7 children an acute illness resembling encephalitis appeared after a period of normal development; 2 had developmental delay and progressive "dystonic cerebral palsy." Later, all 9 displayed typical signs of a disorder of the basal ganglia. In 1 patient with macrocephalus the disorder was diagnosed before the onset of neurological disease; in another it was diagnosed prenatally. Computed tomography and magnetic resonance imaging scans revealed severe generalized cerebral atrophy, most striking in the frontal and temporal lobes in 10 patients. Further deterioration was halted after initiation of treatment consisting of low-protein diets, special formulas low in lysine and tryptophan, and supplements of riboflavin and L-carnitine. Only 1 patient showed a slight clinical improvement. Later, dietary therapy was discontinued in 2 older patients and relaxed in a third without observed adverse effects. Two patients in whom treatment could be initiated before the onset of neurological symptoms have developed normally. However, duration of follow-up (6 and 29 months) does not yet allow classification of glutaryl-coenzyme A dehydrogenase deficiency as a treatable disorder. Total body production of glutaric acid, reflected in the daily urinary output, was efficiently reduced by therapeutic measures. Levels of glutaric acid in plasma and cerebrospinal fluid remained unchanged, which may in part explain the overall unsatisfactory outcome. All patients presented with a severe secondary deficiency of carnitine.(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative diagnosis of Mycobacterium avium lymphadenitis in two immunocompetent children by polymerase chain reaction of gastric aspirates.

BACKGROUND: Analysis of gastric aspirates is a routine procedure for detection of Mycobacterium tuberculosis in pediatric pulmonary tuberculosis. However, identification of nontuberculous mycobacteria in gastric aspirates of immunocompetent children is not thought to be clinically significant. METHODS: A PCR method was devised for the detection of M. avium in clinical specimens. The method is based on the amplification of a M. avium-specific DNA fragment present in the 3'-end of the repetitive element IS1245. Surgically removed lymphatic tissue was analyzed prospectively by microscopy, culture and PCR in 13 children admitted to our hospital with suspected mycobacterial lymphadenitis. In 4 of these children 1 to 4 gastric aspirates were obtained before surgical treatment and submitted to the same analysis. RESULTS: We report the detection of M. avium in the gastric aspirates of two children with cervical lymphadenitis before surgical intervention by a novel PCR method. The subsequently surgically removed lymph nodes were also positive by PCR and culture. In one child cultures of both sources grew M. avium. The isolates could be identified as the same strain by DNA fingerprinting. The PCR assay was almost twice as sensitive as culture in detecting M. avium. CONCLUSIONS: Our findings suggest the possibility for noninvasive diagnosis of cervical lymphadenitis caused by nontuberculous mycobacteria before surgery. In addition detection of M. avium in gastric aspirates without evidence of fistula formation provides new insights into the pathogenesis of mycobacterial infection and disease in immunocompetent children.

Influence of n-6 and n-3 polyunsaturated fatty acids on the resistance to experimental tuberculosis.

It has previously been shown that the n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (20:5(n-3)) and docosahexaenoic acid (22:6(n-3)) possess antiinflammatory properties and can interfere with immune functions. To evaluate whether this would affect resistance to infection, we studied the influence of different types of fatty acids (FAs) on experimental tuberculosis in an animal model. Three groups of 26 weanling guinea pigs were fed isocaloric diets with 26 cal% fat that differed in FA composition with respect to saturated FAs, linoleic acid (18:2(n-6)), eicosapentaenoic acid (20:5(n-3)), and docosanexaenoic acid (22:6(n-3)) as follows: (1) reference (REF) group: 14.8 cal% saturated FAs and 2.8 cal% linoleic acid; (2) n-6 group: 4.6 cal% saturated FAs and 15.4 cal% linoleic acid; (3) n-3 group: 6.3 cal% saturated FAs, 10 cal% linoleic acid, 1.4 cal% eicosapentaenoic acid, and 0.9 cal% docosahexaenoic acid. After 13 weeks, 18 animals from each group were intramuscularly injected with 180 colony-forming units (CFU) Mycobacterium tuberculosis strain H37Rv. Eight noninfected animals per group served as controls. Seven weeks later, the mean number of mycobacteria recovered from the spleens of the n-3 group (log 4.34 CFU, standard error of the mean [SEM], 0.12) was significantly higher than from the REF group (log 3.90 CFU; SEM, 0.15) and the n-8 group (log 3.93 CFU; SEM, 0.13; P < .05). In addition, the Root Index of Virulence (RIV) showed the most pronounced progression of the disease in the n-3 group. The mean size of the tuberculin reaction was larger in the n-3 group than in the other groups (P < .05). There was no significant difference between the n-6 group and the REF group. We conclude that supplementing the diet with n-3 FAs eicosapentaenoic acid and docosahexaenoic acid can affect resistance to M tuberculosis, whereas supplementing with n-6 FAs does not.

Primary and secondary disturbances in trace element metabolism connected with genetic metabolic disorders.

Several primarily inherited disturbances of minerals and trace elements have been discovered within the last 20 years. Secondary disturbances of selenium and zinc induced by dietetic treatment of inborn errors of metabolism and by parenteral nutrition also came to our knowledge recently. Two main types of chronic or primary hypomagnesaemia are known which are caused either by impaired intestinal absorption or by false magnesium handling by the kidneys. In acrodermatitis enteropathica, an autosomal-recessive inherited disease leading to characteristic skin lesions, alopecia and dystrophy, low zinc concentrations of serum, urine and hair are measured. The intestinal absorption of zinc is reduced. In copper metabolism two inherited diseases are known with low serum and usually caerulosplasmin concentrations. In Menkes' steely hair syndrome (trichlpoliodystrophy) an intestinal net malabsorption of copper exists, whereas in Wilson's disease the copper contents of several organs are increased.

The influence of vitamin B-6 on cystathioninuria in premature infants.

The amount of cystathionine excreted in the urine of premature infants, ages 10 to 17 days, decreases after oral administration of 40 mg vitamin B-6 daily. Thus, it can be speculated that in vivo cystathionase of premature infants may be induced or activated by pyridoxine.

Alpha-ketoadipic aciduria: degradation studies with fibroblasts,.

Observation of one patient with alpha-ketoadipic aciduria initiated degradation studies with radiolabelled lysine metabolites in fibroblasts in order to localise the metabolic defect. Liberation of 14-CO-2 from alpha-D,L-(1-14-C) aminoadipate and alpha-(1-14-C) ketoadipate was considerably less in the patient's fibroblasts than in the patient's fibroblasts than in normal controls, whereas 14-CO-2 production from (1,5-14-C) glutarate was in the normal range. These results indicate a defect in the oxidative decarboxylation of alpha-ketoadipate as the probable cause of alpha-ketoadipic aciduria; Cultured amniotic fluid cells from pregnancies of the 15th and 16th week of gestation degrade alpha-(1-14-C) ketoadipate with a similar activity to fibroblast cultures from normal humans after birth.

Serum-selenium concentrations in patients with maple-syrup-urine disease and phenylketonuria under dieto-therapy.

Serum-selenium concentrations were measured in 2 dietetically treated patients with maple-syrup-urine disease, in 11 dietetically treated patients with phenylketonuria, in 37 healthy children of different ages and in 183 healthy adults. The estimations were performed by instrumental neutron activation analysis. The values of the dietetically treated patients were much lower than those of healthy children of the same age group. Within 8 to 12 weeks the serum-selenium concentrations decreased from normal values before therapy to very low values under dieto-therapy. During infancy the serum-selenium concentrations of healthy individuals show an increase to the adult range of values.

Correlations between branched-chain amino acids and branched-chain alpha-keto acids in blood in maple syrup urine disease.

In 62 blood samples from 3 patients with classical maple syrup urine disease and from one patient with a variant form, a close linear correlation was found between levels of branched chain amino acids and their corresponding alpha-keto acids. Keto acids were determined as O-trimethylsilyl quinoxalinols by gas chromatography with a nitrogen-selective detector.

Glutaric aciduria type II: report on a previously undescribed metabolic disorder.

A report is given on a hitherto undescribed metabolic disorder, characterized clinically by fatal neonatal acidosis, hypoglycemia and a strong 'sweaty-feet' odour. Biochemical features were a massive urinary excretion of glutaric and lactic acids. Isobutyric, isovaleric and alpha-methylbutyric acids were also greatly increased, followed by adipic, ethylmalonic, alpha-hydroxybutyric, n-butyric, beta-hydroxybutyric, sebacic, suberic, propionic, alpha-hydroxyisovaleric and hexanoic acids. The serum level of glutaric acid was highly elevated. In the serum there were also abnormal levels of lactic, alpha-hydroxybutyric, adipic, suberic, p-hydroxyphenyllactic, myristic, hexadecenoic, palmitic, oleic and stearic acids. Plasma lysine and valine were also elevated. Degradation of 14C-labelled glutaric acid and 14C-labelled branched-chain amino acids, alpha-ketoisovaleric and alpha-ketoisocaproic acids in intact fibroblasts was decreased, whereas that of pyruvic acid was normal. The defect was tentatively supposed to be localized at the level of the metabolism of a range of acyl-CoA compounds. The name glutaric aciduria 'type II' is proposed for the patient's disease.

Alpha-ketoadipic aciduria, a new inborn error of lysine metabolism; biochemical studies.

Investigation of a psychomotorically retarded girl showed excretion of abnormal amounts of alpha-ketoadipic acid, alpha-hydroxyadipic acid, alpha-aminoadipic acid, 1,2-butenedicarboxylic acid and elevation of plasma alpha-aminoadipic acid levels. The identity of these metabolities was established by various methods. The excretion of alpha-aminoadipic acid correlated to the lysine intake. Degradation studies with cultured fibroblasts indicate a defect in the oxidative decarboxylation of alpha-ketoadipic acid (see Clin. Chim. Acta, 58 (1975) 271.

Facts and artefacts in mevalonic aciduria: development of a stable isotope dilution GCMS assay for mevalonic acid and its application to physiological fluids, tissue samples, prenatal diagnosis and carrier detection.

A stable isotope dilution assay using D3-mevalonic acid was developed and applied to the study of mevalonic aciduria. The method also appears to be suitable for the evaluation of different therapeutic regimens in patients with hypercholesterolemia. Mevalonic acid was isolated by liquid partition chromatography and quantified as the underivatized lactone by means of ammonia chemical ionization selected ion monitoring capillary gas chromatography-mass spectrometry. In heterozygotes there was significantly greater urinary excretion of mevalonic acid, while the range of enzymatic activity of mevalonate kinase showed an overlap with that of controls. The analysis of amniotic fluids of two pregnancies at risk for mevalonic aciduria showed a 3277-fold elevation as compared to controls in the first case, diagnostic of an affected fetus, and a normal value in the second one. Mevalonic acid concentration was much increased in tissues of the affected and aborted fetus. Concentrations ranged from 840 to 1120 mumol/kg in various tissues and were as high as 1810 mumol/kg in brain. Concentrations in control fetal tissues were approximately 1 mumol/kg.

D-Glyceric acidemia in a patient with chronic metabolic acidosis.

A patient is described with glyceric acidemia and glyceric aciduria. The main clinical problems in infancy were severe metabolic acidosis and failure to thrive. The patient needs permanent treatment with bicarbonate. Hyperglycinemia, as described in the first case discovered elsewhere, was not present. The glyceric acid was found to have the D-configuration, as analyzed by capillary gas chromatography of its di-O-acetyl-l-menthyl ester. The abnormality may result from a defect in serine metabolism.

Scaly skin alterations and plasma fatty acids in Congolese children.

Scaly skin alterations on the surface of the legs are frequently found in African children. Because similar signs occur in essential fatty acid deficiency, the fatty acid status of a group of African children with (n = 10) and without (n = 27) such skin alterations was determined. Analysis of the fatty acid composition of the plasma phospholipid and cholesterol ester fractions as well as clinical examinations were performed. Constantly low levels of linoleic acid and arachidonic acid were not associated with the occurrence of scaly skin alterations, which were also found in children with normal values for these polyunsaturated fatty acids. It is suggested that scaly skin alterations in Congolese children are not a sign of essential fatty acid deficiency.

Effects of dietary supplementation of saturated fatty acids and of n-6 or n-3 polyunsaturated fatty acids on plasma and red blood cell membrane phospholipids and deformability in weanling guinea pigs.

The fatty acid composition of plasma cholesteryl esters, plasma phospholipids, red blood cell (RBC) membrane phosphatidylcholine (corresponding to the outer membrane leaflet), and phosphatidylethanolamine (corresponding to the inner membrane leaflet) was investigated in weanling guinea pigs fed with diets of cacao (saturated fatty acids), sunflower oil [n-6 polyunsaturated fatty acids (PUFA)] or fish oil (n-3 PUFA) for 20 wk. RBC deformation was measured by means of a cell-transit analyzer (filtration) and a cone-plate rheoscope. The contents of saturated fatty acids in plasma phospholipids and RBC membrane leaflets were similar in all three groups. Diets with sunflower oil resulted in a high content of linoleic acid in plasma cholesteryl esters and in the outer leaflet of RBC membranes. Fatty acids of fish oil were mainly incorporated in plasma phospholipids and in the inner leaflet of RBC membranes. The arachidonic acid content was high in all groups in the plasma phospholipids and in the inner leaflet. The n-6 and n-3 PUFA were mainly incorporated in the inner leaflet. In all groups the polyunsaturated/saturated fatty acid ratio and the total PUFA content were similar in the inner RBC membrane. The RBC filtration times and the RBC deformation indices were not affected by the dietary treatment.

Rubidium-A possible essential trace element : 1. The rubidium content of whole blood of healthy and dietetically treated children.

The rubidium content of whole blood was estimated by instrumental neutron activation analysis. In 46 healthy children it amounts to {ie193-1} g/g dry weight. There was no difference between the values found for infants, toddlers, and school children. In 29 dietetically treated patients with phenylketonuria and maple-syrup-urine disease the values were significantly lower than in healthy children. During the first three months of diet therapy the rubidium levels remained in the lower range of the normal values, decreasing to about 60% of the mean of normal values later on. With increasing length of diet therapy these values tended to decrease. It remains questionable whether these decreased levels reflect only an induced biochemical phenomenon without biological importance, or whether they are the first signs of a deficiency syndrome.

Platelet selenium in children with normal and low selenium intake.

The concentration of selenium was determined by instrumental neutron activation analysis in erythrocytes, platelets, and plasma of eight dietetically treated children with phenylketonuria (n=6) or maple-syrup-urine disease (n=2) with low selenium intake and for ten children with normal selenium intake. The normal selenium concentration in platelets was about 600 ng/g and about five times higher than in erythrocytes of the same children. A decreased selenium concentration in platelets was seen only when the corresponding concentrations in erythrocytes and plasma were very low. This suggests a special role of selenium in platelets.

Vitamin E status of Congolese children in a rural area.

The role of vitamin E in severe malnutrition is controversially discussed. In order to evaluate the vitamin E status of unselected African children the plasma tocopherol levels of 52 children from a village in the People's Republic of Congo were assessed by HPLC and related to the plasma lipid values. Although plasma concentrations of total tocopherols (mean 351.1 +/- 59.4 micrograms/dl) and alpha-tocopherol (mean 313.3 +/- 57.0 micrograms/dl) were found to be low, normal ratios of total tocopherols to total lipids (mean 0.99 +/- 0.17 mg/g) and alpha-tocopherol to total lipids (mean 0.89 +/- 0.09 mg/g) were estimated. It is concluded that plasma vitamin E levels should be related to plasma lipids if populations are monitored in which low lipid concentrations have to be expected. These data on Congolese children may be used for comparison if the vitamin E status in other agrogeographical areas of Africa or in clinically abnormal groups is investigated.