Reference ranges of serum bile acids in children and adolescents.

BACKGROUND: Bile acids (BA) are found predominantly in bile but also in serum, where they can be used as markers for inborn and acquired hepatobiliary disorders. We measured serum BA levels by mass spectrometry to determine reference ranges for healthy children and adolescents in different age groups. METHODS: In 194 healthy children and adolescents (0-19 years) concentrations of serum BA and BA composition were determined using high-performance liquid chromatography high-resolution mass spectrometry. Individuals were classified by ages into five groups: 0-5 months, 6-24 months, 3-5 years, 6-11 years, and >11 years. RESULTS: The 95% confidence interval of serum total BA values in newborns was 3.85-6.32 µmol/L. In the cohort aged 6-24 months total BA values were significantly higher (6.61-9.43 µmol/L; p<0.001). During growth, values decreased (6-11 years; 3.61-5.41 µmol/L), and after 11 years (3.09-4.12 µmol/L) resembled those in adults (0.28-6.50 µmol/L). With respect to conjugation patterns, in neonates BA were primarily conjugated with taurine; however, after 6 months glycine conjugates clearly predominated. CONCLUSIONS: Our data show that serum BA values vary substantially during the first years of life and that reference ranges for BA are age-dependent. The physiologic mechanisms underlying these variations remain to be determined.

Relation between biomarkers and clinical severity in patients with Smith-Lemli-Opitz syndrome.

UNLABELLED: Smith-Lemli-Opitz syndrome (SLOS), a multiple congenital anomaly with severe mental retardation, is caused by decreased activity of 7-dehydrocholesterol reductase. Fifteen Hungarian patients were diagnosed with SLOS on the basis of clinical symptoms, serum cholesterol, 7-dehydrocholesterol, and molecular genetic testing. Their age at the time of diagnosis in mild SLOS (n = 4, clinical score <20) was 0.5-18 years, cholesterol was 2.37 ± 0.8 mmol/L, and 7DHC was 0.38 ± 0.14 mmol/L. In the group of typical SLOS (n = 7, score 20-50), the diagnosis was set up earlier (age of 0.1-7 years); t-cholesterol was 1.47 ± 0.7 mmol/L, and 7DHC was 0.53 ± 0.20 mmol/L. Patients with severe SLOS (n = 4, clinical score > 50) died as newborns and had the lowest t-cholesterol (0.66 ± 0.27 mmol/L), and 7DHC was 0.47 ± 0.14 mmol/L. Correlation coefficient with clinical severity was 0.74 for initial t-cholesterol and 0.669 for Cho/7DHC. Statistically significant difference was between the initial t-cholesterol of mild and severe SLOS (p = 0.01), and between the Cho/7DHC ratios of groups (p = 0.004). In severe SLOS, the percentage of α-lipoprotein was significantly lower than in typical (p = 0.003) and mild SLOS (p = 0.004). Although serum albumin, total bilirubin, and hemostasis parameters remained in the reference range during cholesterol supplementation (n = 10) combined with statin therapy (n = 9), increase of aspartate aminotransferase and alanine aminotransferase in 50 % of the patients probably refers to a reversible alteration of liver function; therefore, statin therapy was suspended. CONCLUSION: life expectancy is fundamentally determined by the initial t-cholesterol, but dehydrocholesterol and α-lipoprotein have prognostic value. Accumulation of hepatotoxic DHC may inhibit the synthesis of α-lipoproteins, decreasing the reverse cholesterol transport. During statin therapy, we suggest monitoring of lipid parameters and liver function.

The predictive value of immature granulocyte count and immature myeloid information in the diagnosis of neonatal sepsis.

BACKGROUND: To determine the predictive value of the immature granulocyte count and the immature myeloid information in neonatal early onset sepsis we examined 133 blood samples of patients admitted to our neonatal intensive care unit. METHODS: Measurements were performed using the Sysmex XE-2100, an automated hematological analyzer. Patients were divided into two groups: 1) symptomatic neonates with diagnosis of early onset sepsis; and 2) controls including asymptomatic neonates who were admitted because of prematurity, low birth weight, or delayed postnatal transition. RESULTS: The number of immature granulocytes and the immature myeloid information were significantly elevated in neonates with early onset sepsis compared to controls (median 280/µL vs. 50/µL, p=0.049 and 639/µL vs. 89/µL, p<0.0001, respectively). CONCLUSIONS: Automated determinations of immature granulocytes and immature myeloid information seem to be useful adjunctive methods in the diagnosis of neonatal early onset sepsis.

Urinary total globotriaosylceramide and isoforms to identify women with Fabry disease: a diagnostic test study.

BACKGROUND: Fabry disease is a treatable X-linked lysosomal storage disorder caused by alterations in the structural gene (GLA) of α-galactosidase A (AGAL), manifesting with cardiovascular and/or kidney disease and decreased life span. Although males as well as females can be affected, females cannot be identified using AGAL activity. We evaluated urinary total globotriaosylceramide (Gb3) and single N-acyl isoforms for the detection of Fabry disease in female patients with and without chronic kidney disease (CKD). STUDY DESIGN: Diagnostic accuracy study. SETTING & PARTICIPANTS: 28 untreated women with Fabry disease and 335 female outpatients without Fabry disease with (n = 213) and without CKD (n = 122). INDEX TEST: Assessment of urinary Gb3 using electrospray ionization tandem mass spectrometry, including 6 N-acyl isoforms, total Gb3 related to urinary creatinine, and ratios of Gb3-24 to Gb3-18 and Gb3-24 to urinary AGAL. REFERENCE TEST: Fabry disease, diagnosed by identification of known pathogenic GLA mutations in patients or their male relatives. RESULTS: 6 parameters (ratio of Gb3-24 to urinary AGAL activity; Gb3-24; ratio of Gb3-24 to Gb3-18; Gb3-22; Gb3-16; and total Gb3) were highly informative for the diagnosis of Fabry disease independent of the presence or absence of CKD (area under the receiver operating characteristic curve, 0.876-0.927; all P < 0.001). LIMITATIONS: Because of low signal-to-noise ratios, 15.8% of samples had to be excluded. CONCLUSION: Total urinary Gb3 and Gb3 isoforms can be used for the diagnosis of Fabry disease in women.

Biochemical and molecular characterization of 18 patients with pyridoxine-dependent epilepsy and mutations of the antiquitin (ALDH7A1) gene.

Patients with pyridoxine dependent epilepsy (PDE) present with early-onset seizures resistant to common anticonvulsants. According to the benefit of pyridoxine (vitamin B(6)) and recurrence of seizures on pyridoxine withdrawal, patients so far have been classified as having definite, probable, or possible PDE. Recently, PDE has been shown to be caused by a defect of alpha-amino adipic semialdehyde (AASA) dehydrogenase (antiquitin) in the cerebral lysine degradation pathway. The accumulating compound piperideine-6-carboxylic acid (P6C) was shown to inactivate pyridoxalphosphate (PLP) by a Knoevenagel condensation. Pipecolic acid (PA) and AASA are markedly elevated in urine, plasma, and cerebrospinal fluid (CSF) and thus can be used as biomarkers of the disease. We have investigated 18 patients with neonatal seizure onset, who have been classified as having definite (11), probable (four), or possible (three) PDE. All patients had elevated PA and AASA in plasma (and urine) while on treatment with individual dosages of pyridoxine. Within this cohort, molecular analysis identified 10 novel mutations (six missense mutations, one nonsense mutation, two splice site mutations) within highly conserved regions of the antiquitin gene. Seven mutations were located in exonic sequences and two in introns 7 and 17. Furthermore, a novel deletion of exon 7 was identified. Two of the 36 alleles investigated require further investigation. A known mutation (p.Glu399Gln) was found with marked prevalence, accounting for 12 out of 36 alleles (33%) within our cohort. Pyridoxine withdrawal is no longer needed to establish the diagnosis of "definite" PDE. Administration of pyridoxine in PDE may not only correct secondary PLP deficiency, but may also lead to a reduction of AASA (and P6C) as presumably toxic compounds.

HLA genotyping as first-line screening tool for coeliac disease in children with juvenile idiopathic arthritis.

OBJECTIVES: Coeliac disease (CD) and juvenile idiopathic arthritis (JIA) often coexist. This association warrants assessment for CD in patients with JIA. We evaluated the clinical relevance and cost-effectiveness of human leucocyte antigen (HLA) genotyping in first-line screening for development of CD in children with JIA. PATIENTS AND INTERVENTIONS: 95 patients with JIA were screened for CD using CD-specific antibodies. In case of positivity, a small intestinal biopsy was performed to confirm diagnosis. In addition, HLA genotyping was performed. 110 age-matched and sex-matched Caucasian children from the same geographical area served as controls. RESULTS: CD was diagnosed in 4 of 95 patients with JIA (4.2%), a rate significantly higher compared with controls (p<0.02) and 14 times higher than in the general population. Twenty-six patients (27.4%) had one of the variants of the risk genotypes. All four patients diagnosed with CD had a HLA-DQ2.5 genotype: one was homozygote, the remainder heterozygote. Twenty-two patients are, judging by their HLA genotypes, at risk of developing CD and require repeated serological screening. None of the 69 patients without HLA-DQ2/DQ8 genotypes had CD-specific antibodies. Screening with HLA genotyping becomes cheaper than screening without after the second determination. CONCLUSIONS: In our cohort of patients with JIA, lack of HLA-DQ2/DQ8 genotypes identified a majority not at risk of CD in whom repeated serological testing is unnecessary. Genotyping is nowadays the most efficient and cost-effective way to screen for CD risk in JIA.

Combined Respiratory Chain Deficiency and UQCC2 Mutations in Neonatal Encephalomyopathy: Defective Supercomplex Assembly in Complex III Deficiencies.

Vertebrate respiratory chain complex III consists of eleven subunits. Mutations in five subunits either mitochondrial (MT-CYB) or nuclear (CYC1, UQCRC2, UQCRB, and UQCRQ) encoded have been reported. Defects in five further factors for assembly (TTC19, UQCC2, and UQCC3) or iron-sulphur cluster loading (BCS1L and LYRM7) cause complex III deficiency. Here, we report a second patient with UQCC2 deficiency. This girl was born prematurely; pregnancy was complicated by intrauterine growth retardation and oligohydramnios. She presented with respiratory distress syndrome, developed epileptic seizures progressing to status epilepticus, and died at day 33. She had profound lactic acidosis and elevated urinary pyruvate. Exome sequencing revealed two homozygous missense variants in UQCC2, leading to a severe reduction of UQCC2 protein. Deficiency of complexes I and III was found enzymatically and on the protein level. A review of the literature on genetically distinct complex III defects revealed that, except TTC19 deficiency, the biochemical pattern was very often a combined respiratory chain deficiency. Besides complex III, typically, complex I was decreased, in some cases complex IV. In accordance with previous observations, the presence of assembled complex III is required for the stability or assembly of complexes I and IV, which might be related to respirasome/supercomplex formation.

Opposite associations of age-dependent insulin-like growth factor-I standard deviation scores with nutritional state in normal weight and obese subjects.

OBJECTIVE: Insulin-like growth factor-I (IGF-I) has been suggested to be a prognostic marker for the development of cancer and, more recently, cardiovascular disease. These diseases are closely linked to obesity, but reports of the association of IGF-I with measures of obesity are divergent. In this study, we assessed the association of age-dependent IGF-I standard deviation scores with body mass index (BMI) and intra-abdominal fat accumulation in a large population. DESIGN: A cross-sectional, epidemiological study. METHODS: IGF-I levels were measured with an automated chemiluminescence assay system in 6282 patients from the DETECT study. Weight, height, and waist and hip circumference were measured according to the written instructions. Standard deviation scores (SDS), correcting IGF-I levels for age, were calculated and were used for further analyses. RESULTS: An inverse U-shaped association of IGF-I SDS with BMI, waist circumference, and the ratio of waist circumference to height was found. BMI was positively associated with IGF-I SDS in normal weight subjects, and negatively associated in obese subjects. The highest mean IGF-I SDS were seen at a BMI of 22.5-25 kg/m2 in men (+0.08), and at a BMI of 27.5-30 kg/m2 in women (+0.21). Multiple linear regression models, controlling for different diseases, medications and risk conditions, revealed a significant negative association of BMI with IGF-I SDS. BMI contributed most to the additional explained variance to the other health conditions. CONCLUSIONS: IGF-I standard deviation scores are decreased in obesity and underweight subjects. These interactions should be taken into account when analyzing the association of IGF-I with diseases and risk conditions.

Rapid analysis of total plasma homocysteine by tandem mass spectrometry.

Elevated plasma homocysteine levels may be an independent risk factor for premature vascular disease. Early detection and population screening are warranted to recognise hyperhomocysteinemia and initiate homocysteine lowering therapy. Current methods for homocysteine analysis are time consuming, labor intensive and/or expensive. We developed a sensitive and fast method for homocysteine analysis based on tandem mass spectrometry that avoids the need for derivatization and preanalytical chromatography.

Liquid chromatographic method for simultaneous determination of mycophenolic acid and its phenol- and acylglucuronide metabolites in plasma.

A simple, sensitive and reproducible HPLC method is presented for the simultaneous determination of mycophenolic acid (MPA) and its metabolites phenolic MPA-glucuronide (MPAG) and acyl glucuronide (AcMPAG) in human plasma. Sample purification requires protein precipitation with 0.1 M phosphoric acid/acetonitrile in the presence of Epilan D as an internal standard (IS). Separation was performed by reversed-phase HPLC, using a Zorbax SB-C18 column, 32% acetonitrile and a 40 mM phosphoric acid buffer at pH 3.0 as mobile phase; column temperature was 50 degrees C, flow rate 1.4 ml/min, and measurement by UV detection was at 215 nm (run time 12 min). The method requires only 50 microl plasma. Detection limits were 0.1 microg/ml for MPA and AcMPAG, and 2.0 microg/ml for MPAG, respectively. Mean absolute recovery of all three analytes was >95%. This analytical method for the determination of MPA and its metabolites is a reliable and convenient procedure that meets the criteria for application in routine clinical drug monitoring and pharmacokinetic studies.

[DOOR (deafness, onychodystrophy, osteodystrophy, mental retardation) syndrome]. / DOOR- (deafness, onychodystrophia, osteodystrophia, mentális retardáció) szindróma.

Authors highlight the difficulties of syndrome identification through reporting the first case of DOOR syndrome in Hungary (the 28th case worldwide). The awareness and appropriate weighing of the importance of vestigial nails (onychodystrophy) was crucial for the correct diagnosis. Based on the normal level of 2-oxoglutarate excretion, the patient can be categorized as type 2. This is associated with better survival, which does not mean a substantial difference in quality of life. Although, prenatal diagnosis is not possible at present, knowledge of the enzyme defect and detection of the reduced activity of the 2-oxoglutarate dehydrogenase E1 component may provide an opportunity. If parents opt to have another child, a 25% risk is to be taken into account.

Whole-exome sequencing in patients with inherited neuropathies: outcome and challenges.

Inherited peripheral neuropathies (IPN) are one of the most frequent inherited causes of neurological disability characterized by considerable phenotypic and genetic heterogeneity. Based on clinical and electrophysiological properties, they can be subdivided into three main groups: HMSN, dHMN, and HSN. At present, more than 50 IPN genes have been identified. Still, many patients and families with IPN have not yet received a molecular genetic diagnosis because clinical genetic testing usually only covers a subset of IPN genes. Moreover, a considerable proportion of IPN genes has to be identified. Here we present results of WES in 27 IPN patients excluded for mutations in many known IPN genes. Eight of the patients received a definite diagnosis. While six of these patients carried bona fide pathogenic mutations in known IPN genes, two patients had mutations in genes known to be involved in other types of neuromuscular disorders. A further group of eight patients carried sequence variations in IPN genes that could not unequivocally be classified as pathogenic. In addition, combining data of WES and linkage analysis identified SH3BP4, ITPR3, and KLHL13 as novel IPN candidate genes. Moreover, there was evidence that particular mutations in PEX12, a gene known to cause Zellweger syndrome, could also lead to an IPN phenotype. We show that WES is a useful tool for diagnosing IPN and we suggest an expanded phenotypic spectrum of some genes involved in other neuromuscular and neurodegenerative disorders. Nevertheless, interpretation of variants in known and potential novel disease genes has remained challenging.

Culture proven newborn sepsis with a special emphasis on late onset sepsis caused by Enterobacteriaceae in a level III neonatal care unit in Astana, Kazakhstan.

BACKGROUND: Newborn sepsis is one of the major public health concerns worldwide. Also in our neonatal care unit, it is one of the major problems and especially infections with Enterobacteriaceae were noted to pose an increasing problem in the last years. METHODS: Data collection was done retrospectively for 2011. Early onset sepsis was defined as having a positive blood culture within 72 h and late onset sepsis after 72 h of delivery. RESULTS: Out of 599 patients being admitted, 58 newborns were assessed having a neonatal sepsis. Of these 58 newborns with sepsis, 11 were diagnosed within 72 h post delivery (early onset) and 47 were diagnosed after 72 h post delivery (late onset). The percentage of Enterobacteriaceae causing late onset sepsis was 57.5 %. Among these, Klebsiella pneumoniae could be isolated in 29.8 %, Enterobacter cloacae in 12.8 %, Enterobacter aerogenes in 8.5 %, and Escherichia coli in 6.4 % of late onset sepsis. Majority of the strains showed a resistance to antibiotics used in empiric treatment. Antibiotic prophylaxis/treatment from birth until the onset of late onset sepsis could be analyzed in 20 out of 27 newborns with late onset sepsis caused by Enterobacteriaceae. A regimen of empirical antibiotic treatment containing aminopenicillin and/or gentamicin was administered in 16 newborns and that of cephalosporin in 14 out of 20 newborns for at least 5 days before onset of sepsis. CONCLUSIONS: The association of empiric long-term antibiotic treatment and the high number of late onset sepsis with often multiresistant Enterobacteriaceae might be causal and urges for a change in general antibiotic prophylaxis/treatment in newborns admitted to the neonatal care unit of our hospital.

Adipose tissue as a source of nicotinamide N-methyltransferase and homocysteine.

Nicotinamide N-methyltransferase (NNMT) catalyses the conversion of nicotinamide to 1-methylnicotinamide and plays an important role in hepatic detoxification reactions. Here we show that, in addition to the liver, 3T3-L1 adipocytes as well as human and murine adipose tissue explants express high amounts of enzymatically active NNMT. NNMT mRNA levels and enzyme activity increased in 3T3-L1 cells in a differentiation-dependent manner. Homocysteine, the atherogenic product of the NNMT-catalyzed reaction, was secreted from 3T3-L1 cells or adipose tissue cultures. Homocysteine release increased during 3T3-L1 differentiation and was reduced when adipose tissue was treated with the NNMT inhibitor 1-methylnicotinamide. Nicotinic acid (NA), a widely used drug to lower elevated plasma lipid levels, induced NNMT enzyme activity in white adipose tissue of mice. In tissue culture nicotinamide treatment led to an increase in adipose tissue homocysteine secretion. These data support the concept that adipose tissue NNMT contributes to the increased plasma homocysteine levels in patients treated with NA.

Reference ranges for neuroprotein S-100B: from infants to adolescents.

BACKGROUND: Diagnosis and treatment of mild traumatic brain injuries in children are especially problematic. At present, computed tomography (CT) is the standard method to identify if patients with intracranial lesions require inpatient monitoring. CT, however, involves exposure to high doses of X-rays, which should be avoided if possible. In adults, the serum level of neuroprotein S-100B has already been proven to be effective for the selection of patients requiring CT. The aim of the present study was to determine reference ranges for serum S-100B in a large number of healthy children. METHODS: All patients younger than 18 years with no recent history of head injuries presenting for routine operations were included in the study. RESULTS: A total of 394 patients were evaluated. In children from 3 to 18 years an upper reference level of 0.16 microg/L was determined. There was a strong inverse relation between age and S-100B in patients younger than 3 years. As the values in this age group were scattered and the number of cases limited (n=65), no reference range could be calculated. CONCLUSIONS: This study provides S-100B reference ranges for pediatric patients based on the largest group of healthy pediatric patients yet analyzed.

Rapid determination of urinary globotriaosylceramide isoform profiles by electrospray ionization mass spectrometry using stearoyl-d35-globotriaosylceramide as internal standard.

Globotriaosylceramide is a neutral glycolipid containing the trihexoside Gal(alpha1-4)Gal(ss1-4)Glc(ss1-1') covalently bound to N-acylsphingosine. It was identified as the main storage substance in the kidney of patients with Fabry disease, an X-linked deficiency of lysosomal alpha-galactosidase A which can significantly be ameliorated by enzyme replacement therapy. Unlike hemizygote males, affected heterozygote females cannot be identified by enzyme assays and therefore may remain untreated. A quantitation of urinary globotriaosylceramides was proposed as an alternative method for their diagnosis. However, the required studies on physiological and pathological variations in the excretion of trihexosides so far have been prevented by a lack of suitable methods. A validated, robust and quick high-throughput method for the quantitative analysis of globotriaosylceramide isoforms using stable-isotope-dilution/internal standardization and electrospray ionization mass spectrometry (ESI-MS) was developed. An internal standard, stearoyl-d35-globotriaosylceramide, was synthesized by enzymatic coupling of d35-stearic acid to the corresponding lyso-ceramidetrihexoside. Glycolipid isoforms of high purity were obtained from a 5-mL urine portion by extraction on C18 solid-phase columns and a novel washing protocol. ESI-MS analysis was performed in full and neutral loss scan modes. Urinary trihexosyl- and some of the di- and monohexosylceramide isoforms can be quantified within a single experiment. All glycolipid isoforms were above detection limit in healthy male and female subjects (n = 63). Prominent elevations of tetracosanoyl-(C24:0 plus C24:1)-globotriaosylceramides were found in urines from female (>2.5-fold above normals) or male Fabry patients (>5.8-fold above normals), but not among controls. Globotriaosylceramide isoforms shall now be analyzed in Fabry patients, non-genetic kidney disease and healthy subjects to define the conditions for a safe diagnosis of heterozygotes.

Quantitative analysis of clindamycin in human plasma by liquid chromatography/electrospray ionisation tandem mass spectrometry using d1-N-ethylclindamycin as internal standard.

A new method for the quantitative analysis of clindamycin in human plasma by liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) is presented. Recently published methods possess a disadvantage because of their use of internal standards with extraction and ionisation properties different from those of clindamycin. To avoid these problems, d(1)-N-ethylclindamycin was synthesised for use as internal standard by N-demethylation and subsequent d(1)-N-ethylation. Plasma sample preparation was done by an easy and rapid liquid-liquid extraction using ethyl acetate. The method was validated in the expected concentration range for a pharmacokinetic study. Calibration graphs were linear within the range 0.05-3.2 microg/mL plasma. Intra-day precision was between 0.90% (2.8 microg/mL) and 3.25% (0.05 microg/mL), inter-day variability was found to be between 1.33% (0.7 microg/mL) and 2.60% (0.05 microg/mL). Inter-day accuracy showed deviations between 0.4% (0.05 microg/mL) and -4.8% (0.2 microg/mL). The method is simple and robust, and has been applied to the batch analysis of clindamycin during a pharmacokinetic study.