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Protein phosphorylation is catalyzed by kinases to regulate cellular events and disease states. Identifying kinase-substrate relationships represents a powerful strategy to understand cell biology and disease yet remains challenging due to the rapid dynamics of phosphorylation. Over the last decade, several γ-phosphoryl modified ATP analogs containing crosslinkers were developed to covalently conjugate kinases, their substrates, and their associated proteins for subsequent characterization. Here, kinetics and crosslinking experiments demonstrated that the UV-activated analogs, ATP-aryl azide and ATP-benzophenone, offered the most robust crosslinking, whereas electrophilic ATP-aryl fluorosulfate promoted the most effective proximity-enabled crosslinking. The data will guide future applications of kinase-catalyzed crosslinking to study normal and disease biology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Phosphorylation is a reversible post-translational modification that alters the functions of proteins to govern various cellular events, including cell signaling. Kinases catalyze the transfer of a phosphoryl group onto the hydroxyl residue of serine, threonine, and tyrosine, while phosphatases catalyze the removal. Unregulated kinase and phosphatase activity have been observed in various cancers and neurodegenerative diseases. Despite their importance in cell biology, the role of phosphatases in cellular events has yet to be fully characterized, partly due to the lack of tools to identify phosphatase-substrate pairs in a biological context. The method called kinase-catalyzed biotinylation to identify phosphatase substrates (K-BIPS) was developed to remedy the lack of information surrounding phosphatase biology, particularly focused on substrate identification. In the K-BIPS method, the γ-phosphoryl modified adenosine 5'-triphosphate (ATP) analog, ATP-biotin, is used by kinases to biotin-label phosphoproteins. Because phosphatases must initially remove a phosphoryl group for subsequent biotinylation by ATP-biotin, phosphatase substrates are identified in K-BIPS by comparing biotinylated proteins in the presence and absence of active phosphatases. K-BIPS has been used to discover novel substrates of both serine/threonine and tyrosine phosphatases. This chapter describes the K-BIPS method to enable the identification of substrates to any phosphatases of interest, which will augment studies of phosphatase biology., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Protein phosphatase 1 regulatory subunit 12A (PPP1R12A) interacts with the catalytic subunit of protein phosphatase 1 (PP1c) to form the myosin phosphatase complex. In addition to a well-documented role in muscle contraction, the PP1c-PPP1R12A complex is associated with cytoskeleton organization, cell migration and adhesion, and insulin signaling. Despite the variety of biological functions, only a few substrates of the PP1c-PPP1R12A complex are characterized, which limit a full understanding of PP1c-PPP1R12A activities in muscle contraction and cytoskeleton regulation. Here, the chemoproteomics method Kinase-catalyzed Biotinylation to Identify Phosphatase Substrates (K-BIPS) was used to identify substrates of the PP1c-PPP1R12A complex in L6 skeletal muscle cells. K-BIPS enriched 136 candidate substrates with 14 high confidence hits. One high confidence hit, AKT1 kinase, was validated as a novel PP1c-PPP1R12A substrate. Given the previously documented role of AKT1 in PPP1R12A phosphorylation and cytoskeleton organization, the data suggest that PP1c-PPP1R12A regulates its own phosphatase activity through an AKT1-dependent feedback mechanism to influence cytoskeletal arrangement in muscle cells., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Phosphorylation of proteins by kinase enzymes is a post-translational modification involved in a myriad of biological events, including cell signaling and disease development. Identifying the interactions between a kinase and its phosphorylated substrate(s) is necessary to characterize phosphorylation-mediated cellular events and encourage development of kinase-targeting drugs. One method for substrate-kinase identification utilizes photocrosslinking γ-phosphate-modified ATP analogues to covalently link kinases to their substrates for subsequent monitoring. Because photocrosslinking ATP analogues require UV light, which could influence cell biology, we report here two ATP analogues, ATP-aryl fluorosulfate (ATP-AFS) and ATP-hexanoyl bromide (ATP-HexBr), that crosslink kinase-substrate pairs via proximity-mediated reactions without the need for UV irradiation. Both ATP-AFS and ATP-HexBr acted as cosubstrates with a variety of kinases for affinity-based crosslinking, with ATP-AFS showing more robust complexes. Importantly, ATP-AFS promoted crosslinking in lysates, which demonstrates compatibility with complex cellular mixtures for future application to kinase-substrate identification.

Unlabelled: Dietary treatment of phenylketonuria is well established to be safe and to prevent developmental and mental impairment in patients with low or absent phenylalanine hydroxylase activity. The use of semi-synthetic diets necessitates careful and longitudinal control not only of physical and intellectual development, which are both near normal in well treated patients, but also of potential diet inherent insufficiencies of essential nutrients. Concern has been raised by some reports on growth retardation in young patients on strict diets and on decreased bone density in older phenylketonuric children. The clinical significance of these findings is not known., Conclusion: Changes have been found, although inconsistently, in connection with selenium, zinc, iron, retinol and polyunsaturated fatty acid status in dietetically treated patients with phenylketonuria. Both the mechanism and significance of these changes is doubtful at present.

We have prospectively analyzed the DNA fingerprints of Mycobacterium tuberculosis strains from a random sample of patients with newly diagnosed tuberculosis in Windhoek, Namibia. Strains from 263 smear-positive patients in whom tuberculosis was diagnosed during 1 year were evaluated, and the results were correlated with selected epidemiological and clinical data. A total of 163 different IS6110 fingerprint patterns were observed among the 263 isolates. Isolates from a high percentage of patients (47%) were found in 29 separate clusters, with a cluster defined as isolates with 100% matching patterns. The largest cluster included isolates from 39 patients. One predominant strain of M. tuberculosis caused 15% of cases of smear-positive pulmonary tuberculosis in Windhoek. That strain was also prevalent in the north of the country, suggesting that in contrast to other African countries with isolates with high levels of diversity in their DNA fingerprint patterns, only a restricted number of different strains significantly contribute to the tuberculosis problem in Namibia.

Unlabelled: We report on two siblings suffering from a new congenital tubulopathy. Following normal pregnancies not complicated by polyhydramnios, severe renal losses of potassium, chloride, sodium and magnesium occurred in the first weeks after birth. Calcium metabolism was not affected. The distal tubular chloride reabsorption was considerably decreased in the two siblings (0.25 and 0.28, respectively). Secondary hyperaldosteronism, activation of the kallikrein-kinin system and elevated urinary prostaglandin excretion were observed. The effects of indomethacin, spironolactone and captopril on symptoms, electrolyte wasting, activation of renin-angiotensin-aldosterone and kallikrein-kinin system and prostaglandin synthesis were studied. In spite of persisting elevation of prostaglandin synthesis, captopril decreased electrolyte wasting, polyuria and hyperaldosteronism most effectively., Conclusion: We delineate an apparently new disorder characterized by a postnatal onset, an extremely decreased chloride reabsorption with extensive hyperchloriduria and hypermagnesiuria in the presence of normal calcium metabolism. The disorder can be distinguished from other tubulopathies with hypokalaemic alkalosis.

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.

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.

Unlabelled: Treatment of hyperphenylalaninaemias due to phenylalanine hydroxylase deficiency with a low phenylalanine (Phe) diet is highly successful in preventing neurological impairment and mental retardation. There is consensus that, for an optimal outcome, treatment should start as early as possible, and that strict blood Phe level control is of primary importance during the first years of life, but for adolescent and adult patients international treatment recommendations show a great variability. A working party of the German Working Group for Metabolic Diseases has evaluated research results on IQ data, speech development, behavioural problems, educational progress, neuropsychological results, electroencephalography, magnetic resonance imaging, and clinical neurology. Based on the actual knowledge, recommendations were formulated with regard to indication of treatment, differential diagnosis, and Phe level control during different age periods. The development of the early-and-strictly-treated patient in middle and late adulthood still remains to be investigated. Therefore, the recommendations should be regarded as provisional and subject to future research. Efficient treatment of phenylketonuria has to go beyond recommendations for blood Phe level control and must include adequate dietary training, medical as well as psychological counselling of the patient and his family, and a protocol for monitoring outcome., Conclusions: Early-and-strictly-treated patients with phenylketonuria show an almost normal development. During the first 10 years treatment should aim at blood Phenylalanine levels between 40 and 240 micromol/L. After the age of 10, blood phenylalanine level control can be gradually relaxed. For reasons of possible unknown late sequelae, all patients should be followed up life-long.

Background: An increasing number of children with hereditary tubular disorders (HTD) reach adult life due to diagnostic and therapeutic advances which results in growing need to manage these patients by adult centres. Data on the prevalence and the late clinical problems of these patients are limited., Methods: We observed 177 paediatric patients with isolated or complex HTD between 1969 and 1994. The median age at the time of diagnosis was 3 (range 0-18) years and the median observation period 10 (range 1-43) years. The long-term outcomes with respect to renal function, bone disease, and body growth were analyzed., Results: The prevalence of HTD was 3.2% of all patients observed in our renal unit and 14% of those patients with chronic renal failure and/ or end-stage renal disease. The three most frequent disorders observed were nephropathic cystinosis (n = 34), X-linked hypophosphataemic rickets (n = 26), and idiopathic hypercalciuria (n = 17). At the last observation, 12% of the patients with isolated HTD and 30% of those with complex HTD had developed preterminal chronic renal failure; end-stage renal disease was observed in 5 and 25%, respectively (p < 0.001). Progressive disease occurred mainly in patients having cystinosis, primary hyperoxaluria, the syndrome of hypomagnesaemia/hypercalciuria, primary Fanconi syndrome, Fanconi-Bickel syndrome, and methylmalonic aciduria. Nephrocalcinosis was found in 42%, urolithiasis in 14%, bone deformities and/or fractures in 28%, and other extrarenal alterations in 29% of all patients. The median body height at last observation was 2.0 SD below the normal mean (range from -10.4 to +2. 6), and the adult height was subnormal in 48% of 67 grown-up patients. Growth retardation was more severe in complex than in isolated HTD. The mortality decreased from 17% in 1969-1981 to 12% in 1982-1994., Conclusion: Although HTD are rare nephropathies, their frequently progressive course associated with extrarenal complications requires the attention of nephrologists beyond the paediatric age.

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.

Unlabelled: Due to the observation of severe neurological symptoms in single patients as well as brain imaging, neuropsychological and neurophysiological abnormalities, the long-term prognosis of treated phenylketonuria is still under discussion. We investigated the neurological outcome of 57 (24 male, 33 female) patients with phenylketonuria (diet onset < 3 months) at a mean age of 23.6 (17-33) years in comparison to control subjects. Methods used were a clinical-neurological examination, tests for fine motor abilities, IQ test (WAIS-R), a neuropsychological attention task and MRI (30 patients only). Tremor was increased in the patients (28%) compared to controls (15%). Fine motor abilities were significantly reduced in three areas: hand-wrist steadiness, finger-hand dexterity and hand-wrist speed. Tremor as well as reduced fine motor skills were not associated with treatment-related variables, e.g. diet onset, strictness of biochemical control or amount of MRI white matter change. IQ was lower in patients (mean 97.6) compared to matched control subjects (mean 105.5). IQ at 12 years was correlated with biochemical control from birth up to the age of 12 and remained stable up to adult age, independent of biochemical control after 12 years of age. In contrast to the other outcome parameters, the performance in a neuropsychological attention task was influenced by the concurrent plasma phenylalanine concentration. Specific late-onset neurological impairment was not identified in this sample of early-treated adults with phenylketonuria., Conclusion: Careful neurological investigation revealed subtle symptoms of brain damage even after early-initiated treatment in adult patients with phenylketonuria. At present it cannot be excluded that further neurological deterioration could emerge later in life. Thus, patients with phenylketonuria - either on or off diet - should be monitored throughout life.

It has been reported that children with classical phenylketonuria (PKU) have reduced levels of arachidonic acid (AA, 20:4 n-6) and docosahexaenoic acid (DHA, 22:6 n-3) in plasma and membrane phospholipids compared to controls and may therefore require supplementation. However, it is not established that these changes are specific for PKU. They may as well be attributed to the specific composition of a largely vegetarian diet used for dietary PKU treatment. We therefore investigated the fatty acid composition of plasma phospholipids (PL), plasma cholesterol esters (CE), red blood cell phosphatidylcholine (PC), and red blood cell phosphatidylethanolamine (PE) in two groups of PKU patients including 8 children between 1 and 6 years (group A), 9 adolescents between 11 and 18 years (group B), and 20 age-matched healthy controls. Group A had good dietary control (median plasma phenylalanine 272 mumol/L during the last 6 months before phospholipid analysis) while median phenylalanine in group B was 714 mumol/L (p < 0.001). When compared to age-matched controls, group A showed significantly lower DHA levels in PE (4.21 vs 5.85 weight% (wt%), p < 0.01), in PC (1.02 vs 1.25 wt%, p < 0.05) and in CE (0.25 vs 0.54 wt%, p < 0.05). There was no significant difference of DHA between group B and controls. AA levels were similar in phospholipids of all groups. We conclude that reduced levels of long-chain polyunsaturated fatty acids in PKU patients occur only in those patients with strict dietary therapy with respect to n-3 fatty acids, most probably caused by reduced intake of n-3 fatty acids.

Nontuberculous mycobacterial lymphadenitis presents an increasing clinical problem in immunocompetent young children. A slowly growing, nonphotochromogenic mycobacterium was recovered twice (isolates 2553/91 and 2554/91) from the lymphatic tissue of a child with recurrent cervical lymphadenitis. It could be differentiated biochemically from described Mycobacterium species, although it most closely resembled Mycobacterium malmoense by thin-layer chromatography and high-performance liquid chromatography of mycolic acids. A striking characteristic of the isolate was its high degree of susceptibility to antituberculous drugs in vitro, including isoniazid. Direct determination of the 16S rRNA gene sequence revealed a unique sequence and positioned the strain phylogenetically on a branch separate from M. malmoense within a group of slowly growing mycobacteria that show a high degree of similarity to M. simiae at the 16S rRNA gene level. Despite 99.6% sequence identity with M. simiae at the 16S rRNA gene level, DNA-DNA hybridization studies (hydroxyapatite method) demonstrated DNA relatedness of less than 40%. We conclude that this organism is a new species for which we propose the name M. heidelbergense. A culture of the type strain, strain 2554/91, has been deposited in the American Type Culture Collection as strain ATCC 51253.

Hepatic guanidinoacetate methyltransferase deficiency induces a deficiency of creatine/phosphocreatine in muscle and brain and an accumulation of guanidinoacetic acid (GAA), the precursor of creatine. We describe a patient with this defect, a 4-year-old girl with a dystonic-dyskinetic syndrome in addition to developmental delay and therapy-resistant epilepsy. Several methods were used in the diagnosis of the disease: (1) the creatinine excretion in 24-hour urine was significantly lowered, whereas the creatinine concentration in plasma and in randomly collected urine was not strikingly different from control values; (2) the Sakaguchi staining reaction of guanidino compounds in random urine samples indicated an enhanced GAA excretion; (3) GAA excretion measured quantitatively by guanidino compound analysis using an amino acid analyzer was markedly elevated in random urine samples; (4) in vivo 1H magnetic resonance spectroscopy (MRS) revealed a strong depletion of creatine and an accumulation of GAA in brain; (5) in vivo phosphorus 31 MRS showed a strong decrease of the phosphocreatine resonance and a resonance identified as guanidinoacetate phosphate; and (6) in vitro 1H MRS showed an absence of creatine and creatinine resonances in cerebrospinal fluid and the occurrence of GAA in urine. For early detection of this disease, we recommend the Sakaguchi staining reaction of urine from patients with dystonic-dyskinetic syndrome, seizures, and psychomotor retardation. Positive results should result in further investigations including quantitative guanidino compound analysis and both in vivo and in vitro MRS. Although epilepsy was not affected by orally administered creatine (400 to 500 mg/kg per day), this treatment resulted in clinical improvement and an increase of creatine in cerebrospinal fluid and brain tissue.

A sample of 124 isoniazid (INH)-resistant and 88 susceptible strains of Mycobacterium tuberculosis complex from south, central, and west Africa was analyzed by direct sequence analysis and PCR-restriction fragment length polymorphism analysis of their catalase-peroxidase (katG) genes. Point mutations at codon 315 were found in the genomes of 64% of INH-resistant strains, but no complete deletions were identified. Mutations at codon 463 were independent of INH resistance and were linked to the geographic origins of the strains.

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.

Mycobacterium africanum is a pathogen found in tuberculosis patients in certain parts of Africa and is a member of the Mycobacterium tuberculosis complex. Biochemically, strains of M. africanum exhibit a high degree of variability, with some tendency to cluster according to their geographical origin. To investigate whether this phenotypic variability is reflected at the genetic level, we performed DNA fingerprint analysis of strains isolated from patients with pulmonary tuberculosis in Uganda and Sierra Leone. IS6110 DNA fingerprinting was carried out by the mixed-linker PCR method. A total of 138 strains of M. africanum were analyzed: 42 isolates from Uganda and 96 isolates from Sierra Leone. With few exceptions, the resulting DNA fingerprint patterns grouped together according to their country of origin. A striking lack of variability of DNA fingerprints was found for strains from Sierra Leone, where 70 of 96 isolates (61.5%) fell into clusters. The two largest clusters accounted for 41.7% of all isolates and differed by only one band, as confirmed by standard DNA fingerprinting. In contrast, only two clusters (7.1%) with two and three isolates, respectively, were found for M. africanum isolates collected in Uganda, and three of the DNA fingerprints contained fewer than seven bands. Strains of M. tuberculosis collected and processed during the same time period were highly variable in both countries. Our results support the concept of geographically defined subtypes of M. africanum. In addition, they demonstrate that natural geographic differences in the variability of IS6110 DNA fingerprints within the M. tuberculosis complex must be considered if this technique is used for epidemiologic studies.

Body growth in nine children with primary de Toni-Debré-Fanconi syndrome was followed from birth to adolescence or adult life. At the time of diagnosis, corresponding to the start of treatment, the median age was 2.3 (range 0.4-13.9) years and height standard deviation score (SDS) was always decreased (median -3.5, range -6.8 to -2.1). Despite continuous electrolyte and bicarbonate supplementation only four patients showed a slight improvement in growth. At the time of the last observation at the age of 17.2 (4.5-20.1) years median height was -4.7 (-5.9 to -1.8) SDS. The median difference between height at last observation and target height was -4.5 SDS. Final height (n = 5) ranged between -1.8 and -5.5 (median -4.3) SDS. The pubertal growth spurt was absent in two children. Metabolic acidosis was identified as a significant growth-retarding factor. Mean serial blood bicarbonate levels and height SDS at the last observation were correlated (r = -0.87, P < 0.01). No correlation was observed between last height SDS and the degree of hypokalemia, hypophosphatemia, or hypercalciuria. In conclusion, patients with primary de Toni-Debré-Fanconi-syndrome present severe growth failure at the time of diagnosis which persists into adult life. Supportive therapy is frequently unable to prevent further loss of relative height.

The protein quality of the diets of phenylketonuria (PKU) children of different ages (3 months, 10 months, 3 years, 8 years, 12 years, 16 years) with low or high phenylalanine (Phe) tolerance was assessed according to the recommendations of the FAO/WHO consultation group [13]. The amount of each essential amino acid (AA) per gram dietary protein was calculated and compared to the reference. The resultant amino acid score (AAS) indicated a limited to inadequate biological protein quality of the diets in 3-month-old infants (2.2 g protein/kg body weight/day) and 10-month-old infants (2.0 g protein/kg body weight/day) with a "high" Phe tolerance. In all other age groups the AAS was > 100%. However remarkable imbalances in the AA pattern were apparent. Beginning with the age of 3 years (1.7 g protein/kg body weight/day) the intake of the AA lysine and isoleucine was three or two times higher than recommended. At the age of 8 years (1.4 g protein/kg body weight/day) the intake of three AA (valine, isoleucine, lysine) was-related to the WHO recommendations-217%, 229% and 291%. Similar results could be found in the age groups of 12 years (1.1 g protein/kg body weight/day) and 16 years (0.9 g protein/kg body weight/day), respectively. These calculations might help to reconsider the composition of the AA mixtures used in the dietetic treatment of PKU patients.

In a multicentric and interdisciplinary approach the German Collaborative Study of Children Treated for Phenylketonuria (PKU) investigates prospectively the effects of early started strict dietary treatment on the growth and development of 140 patients. The present paper focuses on longitudinal intelligence data from 4, 5 and 9 years of age of 89 patients in relation to the quality of dietary control in comparison to 200 healthy children tested by the same protocol. Cluster analysis of phenylalanine (Phe) levels distinguished a cluster of good dietary control with Phe levels according to the recommendation of maintaining Phe levels below 360 mumol/l, a cluster of poor dietary control with Phe levels greater than 600 mumol/l after the age of 3 years, and a cluster of intermediate control. Intelligence quotients (IQ) and Phe clusters were inversely related with non-significant differences between the clusters good and intermediate. On average, all three clusters scored significantly lower than healthy age peers. Mean IQ scores decreased for patients as well as for healthy children due to different tests used at different measurement occasions. Patients with poor dietary control showed a steeper decrease between 4 and 5 years than patients with better dietary control. Between 5 and 9 years IQ differences between patients and healthy children remained stable. Verbal IQs were higher than performance IQs for patients as well as for healthy children. It is concluded that after early and strict treatment during the pre-school years Phe levels, in the range observed, do not influence IQ development until the age of 9 years. IQ subscale pattern indicate that PKU results in a generalized reduction of IQ instead of disturbing specific abilities. It remains to be investigated whether higher Phe levels are also innocuous and/or may result in late effects.

The amino acid composition of food products frequently used in the diets of amino acid and protein disorders-including tryptophan- was estimated using ion-exchange column chromatography and high performance liquid chromatography. It includes fruits (different varieties of apples, pears, ananas, bananas, peach, strawberries, honey melon, water melon, kiwi, plums, grapes), vegetables (different varieties of potatoes, potato products, cauli-flower, broccoli, cabbages, spinach, olives, lettuce, cucumber, peas, mushrooms) and commercially available or home-made food products (meat broth, fine gravy paste, ketchup, liquid seasoning, soja sauce, different varieties of Chinese noodles, sausages for phenylketonuria patients), and different new fiber concentrates.

Unlabelled: We report on two siblings, a girl of 7 years and a boy of 2 years, who presented in infancy with hypotonia, athetoid movements, myopathy and severe developmental delay. The progressive clinical course was characterized by ophthalmoplegia, pyramidal tract signs, loss of visual contact and failure to thrive. The older sister died at the age of 7 years. The younger brother followed an almost identical clinical course. MRI of the brain revealed bilateral hypodensities and atrophy of the putamen. Neurophysiological investigations were consistent with peripheral neuropathy. Investigations for neurometabolic disorders in urine, plasma and CSF of both patients revealed a consistent increase of methylmalonic acid in urine, plasma and CSF as well as borderline low free GABA in CSF. Except for an inconstant elevation of lactate in the boy, metabolic acidosis, hypoglycaemia, episodic ketoacidosis, or hyperammonaemia, the usual concomitants of organoacidopathies, were absent in both children. Homocystinuria was excluded. Methylmalonic aciduria did not respond to antibiotic treatment, vitamin B12 therapy nor dietary protein restriction. Incorporation of [14C]propionate into protein in cultured fibroblasts was pathologically but inconsistently decreased. Both patients' cell lines showed only minimal response to hydroxocobalamin and normal methylmalonyl-CoA mutase activity., Conclusion: Even though the definitive underlying enzymatic defect in this sibship remains obscure our results suggest a new genetic disorder. This report illustrates that hitherto undescribed metabolic disorders remain to be elucidated even in long investigated areas of intermediary metabolism such as methylmalonic aciduria.

The fatty acid (FA) composition of samples of breast milk obtained from well-nourished Sudanese women was determined by capillary gas chromatography. Saturated fatty acids (SFA) constituted 46%, monoenoic acids (MONOENE) 33% and polyunsaturated fatty acids (PUFA) accounted for 21% of total fatty acids. The mean value (18.28%) of the essential fatty acid linoleic acid was comparable to the levels reported for well-nourished mothers from industrialised countries. The proportions of fatty acids synthesised de novo in the mammary gland (10:0, 12:0, 14:0) were less than expected from published studies of mothers consuming low fat diet averaging 17.4%. The amount of 22:6 n-3 which is synthesised from 18:3 n-3 and also taken up by consumption of fish were found to be low. The possible nutritional implications of the low n-3 fatty acids for the infants should therefore be investigated.

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.

In the present study eicosanoid synthesis was studied in macrophages of guinea pigs fed different amounts of (n-6)- and (n-3)-polyunsaturated fatty acids (PUFA). Three groups of weanling guinea pigs were fed by isocaloric diets differing only in their contents of PUFA: controls with 2.8 Cal% of linoleic acid (LA; 18:2(n-6)); (n-6)-rich fed animals with 15.4 Cal% of LA; and (n-3)-rich fed animals with 10.1 Cal% of LA, 1.4 Cal% of eicosapentaenoic acid (20:5(n-3)) and docosahexaenoic acid (22:6(n-3)). After 13 weeks half the number of animals from each group was infected i.m. by 180 colony forming units of Mycobacterium tuberculosis strain H37Rv. Seven weeks after infection the release of leukotriene (LT)B4 and prostaglandin (PG)E2 was quantified in calcium ionophore stimulated whole blood, peritoneal macrophage cultures and alveolar macrophages by immunoassays after high performance liquid chromatography. Synthesis of LTB4 and PGE2 was found to be reduced in (n-3)-rich fed guinea pigs (p < 0.05), and equivalent between controls and (n-6)-rich fed animals. Controls and (n-6)-rich fed animals showed the same mycobacterial counts in the spleen whereas (n-3)-rich fed guinea pigs demonstrated an increased number of mycobacteria (p < 0.05). Our results demonstrate that an increased dietary intake of (n-3)-PUFA suppress LTB4 and PGE2 synthesis. The increased number of M. tuberculosis found in the spleens of (n-3)-rich fed animals could represent persistence of the experimental infection. It may be speculated that a functional relationship exists between the two findings.

It has been shown that the detection of tuberculostearic acid (TBSA) with gas chromatography-mass-spectrometry provides a highly specific, sensitive and rapid method for the diagnosis of various forms of tuberculosis. However, the need for complex and expensive equipment prevented the more widespread use of this method. We report on the application of conventional gas chromatography with flame ionization detectors in the detection of TBSA in sputum samples. TBSA was detected in all patients with proven pulmonary tuberculosis before treatment or under treatment for less than 4 weeks (n = 18). Six of these patients (33%) had a negative microscopy result at the time of the study. Sputum samples from patients under therapy for longer than 4 weeks (n = 20) were TBSA-positive in 15 cases (75%). Only in two cases was the diagnosis by microscopy and/or culture not met by TBSA-detection. All sputa of 20 control patients with lung diseases other than tuberculosis were TBSA negative. Additional analysis of patients' data showed a significant relationship (P < 0.005) between the relative amounts of TBSA detectable in the sputum samples and the duration of therapy. It is concluded that conventional capillary gaschromatography may be sensitive and specific enough to be used for the detection of TBSA in sputum of patients with pulmonary tuberculosis.

Neurological manifestations are very common and can be the leading and/or presenting feature in organic acid disorders, sometimes in the absence of metabolic derangement. Review of the time course and presentation of neurological disease in organic acid disorders reveals characteristic clinical findings of ataxia, myoclonus, extrapyramidal symptoms, metabolic stroke and megalencephaly. A group of organic acid disorders presents exclusively with neurological symptoms. These include glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type I), succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria), mevalonic aciduria, N-acetylaspartic aciduria (Canavan disease) and L-2-hydroxyglutaric aciduria. As a group these "cerebral" organic acid disorders appear to remain often undiagnosed and their true incidence is much less well-known than that of the "classical" organic acid disorders. Unfortunately, stringent guidelines for a clinical preselection of neuropaediatric patients to be investigated for organic acid disorders cannot be provided. Today, screening for neurometabolic disorders should be as comprehensive as possible and include determinations of amino acids, purines and pyrimidines and markers of peroxisomal function in addition to organic acid analysis.

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.

In patients with mevalonate kinase deficiency, urinary excretion of the leukotriene LTE4 was found to be elevated. A positive linear relationship between increased urinary excretion of mevalonate and LTE4 (n = 5) suggests that increased cysteinyl leukotriene synthesis is involved in the pathomechanisms of this disease.

Acid-fast bacilli were isolated from lymph nodes of an immunocompetent child presenting with unilateral cervical lymphadenitis. The slowly growing mycobacterium could not be identified by traditional methods. Direct sequencing of the enzymatically amplified 16S rRNA gene revealed a unique sequence belonging to a previously unrecognized mycobacterium. Direct 16S rDNA sequencing enables definitive identification of mycobacterial isolates. The method is useful for rapid recognition of previously unrecognized pathogens.

Aminoacidopathies and organoacidopathies are the most common acute life-threatening inborn errors of metabolism in the neonatal period. In the Federal Republic of Germany approximately 1 out of 5000 newborns is currently diagnosed as having an aminoacidopathy and approximately 1 out of 9000 newborns an organoacidopathy. Especially in the case of organoacidopathies there is substantial evidence that this number represents an underestimation. Many cases of amino- and organoacidopathies are still likely to remain undiagnosed. The incidence figures would warrant neonatal population screening for these disorders; however, the complexity and expense of the current methods prohibit this approach. Instead specialized investigations are carried out in children who develop symptoms indicative of an inborn error of metabolism. This approach is called selective screening. Early diagnosis, therefore, rests on a high degree of suspicion. In this paper clinical and laboratory findings of amino- and organoacidopathies are summarized. They can be nonspecific and misinterpreted. In the neonate and infant the presentation is commonly that of an acute overwhelming disease, whereas in the older child unexplained mental and/or neurological problems are often the leading symptom. We present an algorithm for the quick and comprehensive diagnosis of acutely presenting inborn errors of metabolism using commonly available parameters. However, in many cases the definitive diagnosis is not reached by selective metabolic screening of a single urine specimen of a patient, but requires close cooperation between the referring physician and the metabolic specialist. Multiple analyses, sometimes of different physiological fluids, or even in vivo and in vitro loading tests may be necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Glutaric aciduria type I is due to an impaired glutaryl-CoA-dehydrogenase with an increased urinary excretion of glutaric and 3-OH glutaric acid. Typically, the clinical course until the sixth month or even 3rd year of life is symptom free, and only later an encephalopathic crisis develops. The only symptom of our 4 patients was macrocephaly (head circumference greater than 97. percentile) in early infancy. 3 of them suffered from an encephalopathic crisis at 8 months to 3 years of age; during that time they lost already established abilities as sitting, walking and speaking, and developed choereoathetotic movements. One child aged 15 months was normal beside it's macrocephalus. All children were treated with a diet low in lysine (80 mg/kg BW/day), tryptophane (21 mg/kg BW/day), and by supplementation of L-carnitine (200 mg/kg BW/day) and riboflavine (200 mg/day) and the motorically disturbed children received Lioresal 1 mg/kg BW/day. The effect of this treatment cannot be evaluated so far, but there is evidence that the dietetic therapy together with carnitine supplementation may prevent further deterioration in affected, or an encephalopathic crisis in unaffected patients. Therefore we suggest to investigate organic acids in urine in every child or infant with macrocephalus to exclude glutaric aciduria type I.

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.