ABSTRACT
INTRODUCTION: Patent ductus arteriosus (PDA) is a common problem in preterm newborns. Left vocal cord paralysis (LVCP) can complicate surgical closure if the recurrent nerve is damaged. MATERIALS AND METHODS: A retrospective case series study was conducted on preterm babies diagnosed with PDA in our unit from 1999 to 2013. Their clinical features and treatment complications were reviewed. In those patients that received surgical treatment a telephone questionnaire on the symptoms of LVCP symptoms was completed, and laryncoscopy examination offered. RESULTS: A total of 88 subjects diagnosed with PDA were found, of whom 13.64% (12/88) needed surgery. These patients had a lower gestational age and birth weight. They required mechanical ventilation more frequently, and they had more complications such as, diaphragmatic paralysis, bronchopulmonary dysplasia and intraventricular hemorrhage. One third (3/9) of the surgically treated patients had LVCP, and all of them had dysphonia (100% vs. 16.7%, p=.05). DISCUSSION: LVCP is a common complication of PDA surgery. Further studies are needed to determine its risk factors and its short and long-term consequences.
Subject(s)
Cardiac Surgical Procedures/adverse effects , Ductus Arteriosus, Patent/surgery , Infant, Premature, Diseases/etiology , Postoperative Complications/etiology , Recurrent Laryngeal Nerve Injuries/etiology , Vocal Cord Paralysis/etiology , Female , Humans , Infant, Newborn , Infant, Premature , Male , Recurrent Laryngeal Nerve Injuries/complications , Retrospective StudiesABSTRACT
BACKGROUND: Alcohol consumption during pregnancy, even when moderate, implies a risk of impaired neurodevelopment, physical impairments and malformations. Its early identification is essential for establishing preventive measures to diminish disabilities among newborns. METHODS: To determine the frequency of consumption of substance use in pregnant women, we have used the techniques of gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry to detect drugs and markers of chronic consumption of alcohol in meconium. We performed a prospective study during a period of 10 months among 110 infants in our hospital, assessing anthropometry, neuromuscular development and determination of toxic substances in urine and meconium. Furthermore, meconium analysis identified fatty acid ethyl esters (FAEEs) and ethyl glucuronide (Etg). We also conducted a survey regarding the obstetric history, toxic habits, and employment status of the mothers. RESULTS: According to early detection markers analyzed in meconium (FAEE >1000 ng/g and/or Etg >50 ng/g meconium), 34.65% of pregnant women consumed alcohol during pregnancy, and 17% were positive for both markers. Within the positive cases, 50% of those exceeding a FAEE's value of 5000 ng/g in meconium had low birth-weight children. Only 5/110 mothers (4.5%) admitted to occasional alcohol consumption during pregnancy. Nobody admitted to frequent intake. The cocaine test was positive in three cases; two of them were positive for alcohol as well. CONCLUSION: As expected, many screening devices do not accurately capture use during pregnancy and supplemental methods such as meconium analysis of biomarkers of chronic alcohol consumption may be warranted.
Subject(s)
Alcohol Drinking/adverse effects , Fetal Alcohol Spectrum Disorders/diagnosis , Meconium/chemistry , Prenatal Exposure Delayed Effects/diagnosis , Substance Abuse Detection/methods , Adolescent , Adult , Alcohol Drinking/epidemiology , Biomarkers/analysis , Chromatography, Liquid , Esters/analysis , Fatty Acids/analysis , Female , Fetal Alcohol Spectrum Disorders/epidemiology , Glucuronates/analysis , Humans , Infant, Newborn , Male , Maternal Age , Pregnancy , Prenatal Exposure Delayed Effects/epidemiology , Prospective Studies , Spain/epidemiology , Spectrometry, Mass, Electrospray Ionization/methodsABSTRACT
In this work, different types of gofio produced in the Canary Islands were characterized on the basis of physico-chemical parameters as well as spectral features. An overall of 7 physico-chemical parameters (moisture, ash, pH, Cu, Fe, Mn and Zn) were determined in 64 samples from different cereals and legumes, and IR spectra of all samples were registered. The chemometric processing of both, metal ions contents determined by atomic absorption spectrophotometry, and the MIR spectra, with various techniques including cluster analysis, principal component analysis, and discriminant analysis enabled the accurate characterization and classification of the gofio samples according to the grain used in their obtaining process.
Subject(s)
Edible Grain/chemistry , Flour/analysis , Metals , Spain , Spectrophotometry, Atomic , Spectrophotometry, InfraredSubject(s)
Mandible/surgery , Osteogenesis, Distraction , Pierre Robin Syndrome/surgery , Humans , Infant, Newborn , MaleABSTRACT
Introducción: Las malformaciones congénitas pulmonares (MCP) son infrecuentes y generalmente cursan de forma asintomática en el periodo neonatal. Actualmente, su detección se realiza mediante estudios antenatales, confirmándose en el momento del nacimiento mediante pruebas de imagen. Aunque puede mantenerse una actitud expectante en los pacientes asintomáticos, es recomendable realizar una cirugía programada a los 3-6 meses de vida, dadas las graves complicaciones que pueden presentar estos pacientes. Casos clínicos: Presentamos 4 casos de MCP detectados antenatalmente en nuestro centro en los últimos 6 años, valorando su diagnóstico, características y evolución posterior. Resultados: Los 4 casos fueron malformaciones unilaterales detectadas antenatalmente mediante la ecografía del segundo trimestre, y en 3 de ellos también por resonancia magnética. Uno de ellos es una lesión híbrida, malformación adenomatoidea pulmonar congénita asociada a un secuestro intralobar en el pulmón contralateral. En el momento del nacimiento sólo 1 paciente presentó dificultad respiratoria; los otros estaban asintomáticos. La radiografía simple y la tomografía computarizada (TC) realizadas posnatalmente confirmaron el diagnóstico en 3 pacientes, pero en 1 la radiografía fue normal y la TC posterior demuestra una lesión compatible con atresia bronquial. Se realizó una lobectomía del paciente con dificultad respiratoria neonatal y del paciente con MCP-secuestro, que había presentado una infección pulmonar a los 3 meses. Conclusiones: Nuestra serie aporta 4 casos de excepcional observación. Al tratarse de una patología potencialmente grave, es importante que la conozcan todos los pediatras, así como una implicación multidisciplinaria que permita unificar criterios para proporcionar el mejor manejo posible a nuestros pacientes (AU)
Introduction: Congenital lung malformations are rare and generally have an asymptomatic development in the neonatal period. The detection of this condition is done by antenatal studies and it is later confirmed at birth with imaging tests. Although an expectant attitude towards asymptomatic patients may be adopted, the recommendation is to perform a surgical resection programmed between 3-6 months of life, given the serious complications these patients can suffer. Clinical cases: This study presents 4 cases of congenital lung malformations detected antenatally in our center in the last 6 years focusing on their diagnosis, characteristics and further development. Results: All four cases were unilateral malformations detected antenatally by the second quarter ultrasound, of which three were also detected by nuclear magnetic resonance. One of them was a hybrid lesion (congenital malformation of the lung-pulmonary sequestration) associated with an intralobar sequestration in the contralateral lung. Only one of the cases presented respiratory distress at birth, the others being asymptomatic. The chest-X-ray and axial tomography (CT) done postnatally confirmed the diagnosis in three of the patients; the fourth patient was diagnosed after a CT showed bronchial atresia, despite having a normal chest-X-ray. Lobectomy was performed on the patient with neonatal distress and the patient with the hybrid lesion, who had had a pulmonary infection at 3 months of life. Conclusions: This study provides 4 cases of exceptional observation. Congenital lung malformation is a potentially serious pathology, so it is important for all pediatricians to know about it. Thus, a multidisciplinary involvement is needed so as to unify criteria in order to provide patients with the best specialised care (AU)
Subject(s)
Humans , Male , Female , Infant, Newborn , Lung/abnormalities , Respiratory System Abnormalities/epidemiology , Prenatal Diagnosis/methods , Diagnostic Imaging , Radiography, Thoracic , Tomography , Ultrasonography, PrenatalABSTRACT
Knowledge of hyperphenylalaninemia (HPA) mutational spectrum in a population allows in many cases an accurate prediction of the phenotype and tetrahydrobiopterin (BH4) responsiveness, thus selecting an adequate treatment. In this work, we have performed the molecular characterization of 105 HPA patients from Galicia, in the northwest region of Spain, evaluating their phenotype and BH4 response. The mutational spectrum analysis showed 47 distinct mutations in 89 families, 37 of them (78.7%) corresponding to missense mutations. Six mutations account for 47.2% of all the investigated alleles, each one with a frequency ≥ 5% (IVS10-11G>A, p.R261Q, p.V388M, p.R176L, p.E280K, p.A300S). The most prevalent HPA mutations in Galicia are the common Mediterranean mutation IVS10-11G>A and p.R261Q, with frequencies of 13.8% and 10.5%, respectively. One novel mutation (p.K361Q; c.1081A>C) was also reported. Although a good genotype-phenotype correlation is observed, there is no exact correlation for some genotypes involving mutations p.R261Q, p.I65T or IVS10-11G>A. Forty seven patients were monitored for post-challenge BH4, establishing genotype-based predictions of BH4-responsiveness in all of them. All phenylketonuric patients with 2 nonresponsive mutations were unresponsive to BH4 and patients with mutations previously associated with BH4 responsiveness in the two alleles had a clear positive response to the test, with the exception of 5 patients with mutations p.R261Q, p.I65T and p.R68S. Our study supports a similar degree of heterogeneity of the HPA mutation spectrum in Galicia compared to reported data from Southern Europe. Patients carrying null mutations in both alleles showed the highest degree of concordance with the most severe phenotypes. Genotype is a good predictor of BH4 response.
Subject(s)
Biopterins/analogs & derivatives , Mutation , Phenylalanine Hydroxylase/genetics , Phenylketonurias/epidemiology , Phenylketonurias/genetics , Adolescent , Adult , Biopterins/pharmacology , Child , Child, Preschool , Female , Gene Frequency , Genetic Association Studies , Humans , Male , Molecular Epidemiology , Pedigree , Phenylalanine Hydroxylase/deficiency , Spain/epidemiology , Young AdultABSTRACT
BH4 therapy is an advancement in the treatment of phenylketonuria, reducing blood phenylalanine (phe) levels and increasing tolerance to natural proteins of responding patients. We report the results of 16 patients undergoing long-term BH4 treatment. Responding patients to BH4 was usually based on 24-h loading tests; a ≥30% decrease in blood phe was considered a positive response. Weekly loading made it possible to identify an additional "slow responder." The 16 responders constitute 24.6% of patients who completed the trial (87.5% of responders in mild hyperphenylalaninemia, 38.1% in mild PKU, and 2.8% in classical PKU).Mean dose of BH4 used was 9.75 ± 0.9 mg/kg per day, during a mean of 62 months. Age at treatment start was below 4 years in seven patients; five of which begun treatment during their first month since birth. All but one patient showed good treatment compliance; six continue on BH4 monotherapy without dietary phe restriction; six showed an increase in phe tolerance of 24-55%; and in the five patients who received treatment since the neonatal period an increase in phe tolerance following the phase of maximum growth has persisted. None of the patients showed side effects except one whom vomiting at the beginning of the treatment.Testing at the time of diagnosis in the neonatal period is very appropriate, and if there is a positive response, the patient can be treated with BH4 from onset with the advantage of being able to continue breast-feeding.
ABSTRACT
Neonatal screening of medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is of major importance due to the significant morbidity and mortality in undiagnosed patients. MCADD screening has been performed routinely in Galicia since July 2000, and until now 199,943 newborns have been screened. We identified 11 cases of MCADD, which gives an incidence of 1/18,134. During this period, no false negative screens have been detected. At diagnosis, all identified newborns were asymptomatic. Our data showed that octanoylcarnitine (C8) and C8/C10 ratio are the best markers for screening of MCADD. C8 was increased in all patients and C8/C10 was increased in all but one patient.The common mutation, c.985A > G, was found in homozygosity in seven newborns and in compound heterozygosity in three, while one patient did not carry the common mutation at all. In addition, two novel mutations c.245G > C (p.W82S) and c.542A > G (p.D181G) were identified. Ten of the 11 identified newborns did not experience any episodes of decompensation. The patient with the highest level of medium chain acylcarnitines at diagnosis, who was homozygous for the c.985A > G mutation, died at the age of 2 years due to a severe infection.This is the first report of the results from neonatal screening for MCADD in Spain. Our data provide further evidence of the benefits of MCADD screening and contribute to better understanding of this disease.
ABSTRACT
The Expanded Newborn Screening Program (MS/MS) in the region of Galicia (NW Spain) was initiated in 2000 and includes the measurement of methionine levels in dried blood spots. Between June 2000 and June 2007, 140 818 newborns were analysed, and six cases of persistent hypermethioninaemia were detected: one homocystinuria due to cystathionine ß-synthase (CßS) deficiency, and five methionine adenosyltransferase I/III (MAT I/III) deficiencies. The five cases of MAT I/III deficiency represent an incidence of 1/28 163 newborns. In these five patients, methionine levels in dried blood spots ranged from 50 to 147 µmol/L. At confirmation of the persistence of the hypermethioninaemia in a subsequent plasma sample, plasma methionine concentrations were moderately elevated in 4 of the 5 patients (mean 256 µmol/L), while total homocysteine (tHcy) was normal; the remaining patient showed plasma methionine of 573 µmol/L and tHcy of 22.8 µmol/L. All five patients were heterozygous for the same dominant mutation, R264H in the MAT1A gene. With a diet not exceeding recommended protein requirements for their age, all patients maintained methionine levels below 300 µmol/L. Currently, with a mean of 2.5 years since diagnosis, the patients are asymptomatic and show developmental quotients within the normal range. Our results show a rather high frequency of hypermethioninaemia due to MAT I/III deficiency in the Galician neonatal population, indicating a need for further studies to evaluate the impact of persistent isolated hypermethioninaemia in neonatal screening programmes.
Subject(s)
Amino Acid Metabolism, Inborn Errors/diagnosis , Methionine Adenosyltransferase/deficiency , Methionine/blood , Neonatal Screening/methods , Amino Acid Metabolism, Inborn Errors/blood , Amino Acid Metabolism, Inborn Errors/diet therapy , Amino Acid Metabolism, Inborn Errors/enzymology , Amino Acid Metabolism, Inborn Errors/genetics , Biomarkers/blood , Child Development , Child, Preschool , Early Diagnosis , Female , Genetic Predisposition to Disease , Homocysteine/blood , Humans , Infant , Infant, Newborn , Male , Methionine Adenosyltransferase/blood , Methionine Adenosyltransferase/genetics , Mutation , Pedigree , Phenotype , Predictive Value of Tests , Prognosis , Spain , Tandem Mass Spectrometry , Up-RegulationABSTRACT
The response to tetrahydrobiopterin (BH4) in patients with phenylalanine hydroxylase (PAH, EC 1.14.16.1) deficiency (OMIM 261600) has been widely reported. Here we report results of the BH4 loading test (20 mg/kg per day) in a group of 36 patients with PAH deficiency and phenotype of mild hyperphenylalaninaemia (HPA), mild phenylketonuria (PKU) or classic PKU. The patients ranged from neonates aged 7-15 days, detected in the Newborn Screening Programme for PKU in the population of Galicia (NW Spain), to adults aged up to 32 years who had been receiving a low-phenylalanine (Phe) diet for a period of years. Ten of the 36 patients showed a reduction of more than 30% in plasma Phe levels within 24 h of BH4 loading (ranging from 33.7% to 90.2%, mean 59.2%, SD 19.8%). All the patients with mild HPA (100%) showed a positive response; 57% of patients with mild PKU (4 of 7) showed a positive response. Of particular interest were positive responses in two patients with classic PKU, and in one patient with mutations of the phenylalanine hydroxylase (PAH) gene that have not to date been reported to be BH4-responsive (p.S303A and p.G46S). BH4 treatment (5-8 mg/kg per day) was commenced in 9 of the 10 BH4-responsive patients. The observed responses to treatment argue for application of the BH4 loading test in all patients with HPA or PKU, independently of genotype, phenotype or age.
Subject(s)
Biopterins/analogs & derivatives , Diet, Protein-Restricted , Phenylalanine/blood , Phenylketonurias/diagnosis , Phenylketonurias/drug therapy , Adult , Biopterins/therapeutic use , Humans , Infant, Newborn , Mutation , Patient Selection , Phenylalanine Hydroxylase/genetics , Phenylalanine Hydroxylase/metabolism , Phenylketonurias/diet therapy , Phenylketonurias/metabolism , Predictive Value of Tests , Severity of Illness Index , Treatment OutcomeABSTRACT
The purpose of the present paper is to develop an easy and quick in vitro method to compare copper availability from breast milk and infant formulas. This study focuses on the differences caused by the use of pH 2.0 (adult gastric pH) or pH 5.0 (newborn gastric pH) in the first stage of the enzymolysis. pH affects Cu solubility, a possible estimator of the availability. Selection of a digestor, times of enzymolysis, centrifugation parameters, and Cu determination by ETAAS were discussed as well. Percentage of Cu solubility was larger from breast milk (gastric pH 2.0, 65.3 +/- 14.0 vs 40.0 +/- 13.9%; gastric pH 5.0, 61.2 +/- 16.5 vs 26.6 +/- 10.3%), but the soluble content was larger from infant formulas for both pHs (gastric pH 2.0, 245.3 +/- 82.1 vs 113.0 +/- 103.4 ng mL(-1); gastric pH 2.0, 169.3 +/- 76.9 vs 75.3 +/- 21.9 vs ng mL(-1)).
Subject(s)
Copper/pharmacokinetics , Infant Formula , Milk, Human , Biological Availability , Centrifugation , Copper/analysis , Humans , Hydrogen-Ion Concentration , Infant , Solubility , UltracentrifugationABSTRACT
Multivariate calibration methods that use fluorescence data for the simultaneous determination of furosemide and triamterene were developed. One of the most salient advantages of them is that the vast amount of information provided by the whole spectrum of the sample is not required. This makes analyses simple and fast. The methods require selecting chemometric parameters such as the specific spectral region and number of factors to be used. Both spectral region and number of factors are selected, simultaneously, by minimising the prediction residual error sum of squares (PRESS). The proposed methods were used for the simultaneous determination of the two drugs in real samples (pharmaceutical preparations) with no excipient separation pre-treatment, with furosemide and triamterene contents of 1.68E-3 to 4.31E-2 and 1.03E-3 to 3.12E-2mugml(-1), respectively; as well as that of triamterene at concentrations of 5.00E-4 to 5.80E-3mugml(-1) in urine samples. The ability to construct the calibration validation sets directly from the urine samples itself avoids the need to consider matrix interferences or to pre-treat the sample and/or separate some analytes The results were quite good in all cases.
ABSTRACT
Size exclusion chromatography (SEC) and flame atomic absorption spectroscopy (FAAS) were used for the separation of metal-containing species in milk whey. After milk ultracentrifugation, the sample was injected into a TSK-Gel G2000 glass column and eluted with 0.2M NH4NO3-NH3, pH 6.7. Low molecular weight proteins were fractionated, and the fractions were characterized by molecular weight. Zinc distributions were obtained by FAAS using a high performance nebulizer. The method was very sensitive (limit of detection = 2.6 x 10(-3) microg/mL; limit of quantitation = 8.9 x 10(-3) microg/mL) and precise (RSDs < or =10%). This method was applied to the determination of Zn in binding compounds in breast milk whey and in commercial cow's milk-based formulas. Distribution patterns were different. The presence of Zn in most fractions in breast milk was most significant, whereas in infant formulas Zn was detected only in fractions of molecular weight <5 kDa and in the highest molecular weight peak.
Subject(s)
Chromatography, Gel/methods , Infant Food/analysis , Milk Proteins/analysis , Milk, Human/chemistry , Spectrophotometry, Atomic/methods , Zinc/analysis , Calibration , Humans , Indicators and Reagents , Infant , Molecular Weight , Sensitivity and SpecificityABSTRACT
This method will allow the determination of bound copper to low relative molecular mass compounds in milk. The milk whey obtained by ultracentrifugation was submitted to fractionation by size exclusion chromatography (SEC) on a TSK-Gel2000 (Toso Haas) column with a mobile phase of 0.2 M NH4NO3 + NH3, pH 6.7. Fractions of effluent corresponding to the protein peaks were collected and the copper content was determined by ETAAS. The method was sensitive (LOD 0.4 microgram l-1 and LOQ 1.5 micrograms l-1 in the fraction; LOQ 7.5-22.5 micrograms l-1 referred to the milk sample and depended on fraction volume) and precise (RSD +/- 10%). Media sample recoveries from the column were 101.2%. Cu was predominantly present in fractions corresponding to relative molecular mass 76 and 15 kDa of breast milk while copper was mostly found in fractions corresponding to 14 and 38 kDa of cow's milk-based infant formulae; moreover, copper was eluted in the relative molecular mass region < 6 kDa.
Subject(s)
Copper/analysis , Infant Food/analysis , Milk, Human/chemistry , Chromatography, High Pressure Liquid/methods , Humans , Infant , Infant, Newborn , Spectrophotometry, Atomic/methodsABSTRACT
The wavelength range and number of factors used in partial least-squares (PLS) calibration for the resolution of the dihydralazine (DHZ)-hydrochlorothiazide (HCT) binary mixture and the dihydralazine-hydrochlorothiazide-reserpine ternary mixture were optimized in terms of the relative standard error (R.S.E.) and relative mean standard error (R.M.S.E.). Under the optimum conditions thus established, synthetic mixtures of the analytes can be resolved with errors and relative standard deviations (R.S.D) less than 4.5 and 1.0%, respectively. The ensuing method, which was validated by comparison with high performance liquid chromatography (HPLC), also gives good results with real samples (pharmaceutical preparations).
ABSTRACT
OBJECTIVE: To collect data on hospitalization for respiratory syncytial virus (RSV) infections and presumptive risk factors for rehospitalization among premature infants in Spain. DESIGN: Observational, prospective, longitudinal, multicenter study. SETTING: Fourteen Spanish neonatal units with an annual birth cohort of 57,000 infants. PATIENTS: All children (n = 680) born < or =32 weeks of gestational age between April 1, 1998, and March 31, 1999, and discharged from the hospital before March 31, 1999, were included in the study. A total of 96 were excluded because of administration of prophylactic treatment (n = 55) or were lost to follow-up (n = 41). Five children died during the study period, but death was related to RSV in only 1 case. METHODS AND MAIN OUTCOME MEASURES: Neonatal and demographic data were recorded at the initial visit. Infants were prospectively followed at monthly intervals up to March 31, 1999. In patients rehospitalized for respiratory disorders, further data about RSV status and morbidity were collected. A comparison was made between children rehospitalized for RSV infection and those who were not. The influence of factors on the probability of rehospitalization for RSV infection was assessed by logistic regression analysis. RESULTS: Of the 584 evaluable patients 118 (20.2%) were rehospitalized for respiratory disease during the study period. The causative pathogen was identified in 89 (75.4%) hospital admissions. Of these 59 (66.3%) were a result of RSV infection in 53 children; 6 were reinfections. In a logistic regression model significant independent prognostic variables included: lower risk of RSV hospitalization with increase gestational age [odds ratio (OR), 0.85; 95% confidence interval (CI), 0.72 to 0.99; P < 0.047]; higher risk with chronic lung disease (OR = 3.1; 95% CI 1.22 to 7.91; P < 0.016); and living with school age siblings (OR = 1.86; 95% CI 1.01 to 3.4; P < 0.048). CONCLUSION: This large descriptive study has enabled us to define the influence of specific risk factors that increase the risk of rehospitalization for RSV infection in preterm infants. Such studies help to define the appropriate role of available prophylactic interventions and establish treatment guidelines.
Subject(s)
Pneumonia, Viral/epidemiology , Respiratory Syncytial Virus Infections/epidemiology , Respiratory Tract Infections/epidemiology , Child, Preschool , Chronic Disease , Cohort Studies , Female , Humans , Incidence , Infant , Logistic Models , Male , Multicenter Studies as Topic , Patient Readmission , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Viruses/isolation & purification , Risk Factors , Spain/epidemiologyABSTRACT
Speciation of iron in milk was carried out by high performance liquid chromatography (HPLC) and electrothermal atomic absorption spectrometry (ETAAS). Milk whey was obtained and low molecular weight protein separation was performed by size exclusion chromatography (SEC) with a TSK Gel SW glass guard (Waters) pre-column and a TSK-Gel G2000 glass (Toso Haas) column. After studying water as a possible mobile phase, this mobile phase was carefully selected in order to avoid alterations of the sample and to make subsequent iron determination in the protein fractions easier by ETAAS. The proposed method is sensitive (limit of detection [LOD] and LOQ 1.4 and 4.7 microg l(-1), respectively) and precise (relative standard deviation [RSD]<10%). Iron is principally found in the proteins of 3 and 76 kDa in breast milk, and it is irregularly distributed in infant formulas.