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Received: 30 August 2019 / / Accepted: 25 September 2019 / Published online: 30 October 2019 UDC 613.952-2.468.6
NEUROPROTECTIVE EFFECTS OF D - PENICILLAMINE IN THE NEONATAL PERIOD
Lajos Lakatos1*, Jan Aaseth23, Maryam Dadar4, Geir Bj0rklund5*
1 Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary;
2 Research Department, Innlandet Hospital Trust, Brumunddal, Norway;
3 IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia;
4 Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran;
5 Council for Nutritional and Environmental Medicine (CONEM), Mo i Rana, Norway.
Abstract
Originally D-penicillamine (D-PA) was used due to its potential benefits in the treatment of neonatal hyperbilirubinemia caused by hemolytic diseases in newborn infants or immaturity of the liver enzyme uridine 5'-diphospho-glucuronosyltransferase (UDP-glucuronosyltransferase). In that period, the prevalence of retinopathy of prematurity (ROP) in infants who received treatment with D-PA. Later, studies were performed by different institutes in Poland, Hungary, the USA, Mexico, and India. Short or long-term use of the medication didn't seem to have caused toxicity or intolerance, even D-PA in the newborn period was given in higher doses compared with the doses used in adult patients. Several bilirubin-induced neurologic dysfunctions in the infants, including ROP and autism spectrum disorder, are possibly caused by metal accumulation, unconjugated bilirubin (UCB), as well as UCB-copper complexes in sensitive regions of the central nervous system. Apparently, neonatal hemolysis of red blood cells leads to an unphysiological release of copper and iron from the cells, which pass the blood-brain-barrier (BBB) via the bloodstream. Also, reactive oxygen species contributing to an increased BBB permeability, which creates a dangerous vicious circle in the neonatal brain. In this paper, we present two cases of neonatal hyperbilirubinemia, which indicate the potential neuroprotective effects of D-PA.
Key words: D-penicillamine; copper; bilirubin; neurologic dysfunction; retinopathy prematurity; autism.
Резюме
НЕЙРОПРОТЕКТОРНЫЕ ЭФФЕКТЫ Д - ПЕНИЦИЛЛАМИНА В НЕОНАТАЛЬНОМ ПЕРИОДЕ
Lajos Lakatos1*, Jan Aaseth2,3, Maryam Dadar4, Geir Bj0rklund5*
1 Кафедра педиатрии, медицинский факультет, Дебреценский университет, Дебрецен, Венгрия;
2 Научно-исследовательский отдел, Innlandet Hospital Trust, г. Брумунддал, Норвегия;
3 Первый Московский государственный медицинский университет им. И.М. Сеченова (Университет им. Сеченова), Москва, Россия;
4 Научно-исследовательский институт вакцины и сыворотки Рази, Организация сельскохозяйственных исследований, образования и распространения знаний (AREEO), Карадж, Иран;
5 Совет по питательной и экологической медицине (CONEM), г. Мо и Рана, Норвегия.
D-пеницилламин (D-PA) изначально нашел применение благодаря его потенциальным преимуществам в лечении гипербилирубинемии новорожденных, вызванной гемолитическими заболеваниями или незрелостью фермента печени уридин-5'-дифосфо-глюкуронозилтрансферазы (UDP-глюкуронозилтрансферазы). В тот период была установлена повышенная распространенность ретинопатии недоношенных (ROP) у детей, получавших лечение D-PA. Позднее исследования проводились различными институтами в Польше, Венгрии, США, Мексике и Индии. Кратковременное или длительное использование препарата, по-видимому, не вызывало токсичности или непереносимости, D-PA в период новорожденности даже давали в более высоких дозах по сравнению с дозами, применяемыми у взрослых пациентов. Некоторые вызванные билирубином неврологические дисфункции у детей, включая ROP и расстройства аутистического спектра, возможно, вызваны накоплением металлов, неконъюгированным билирубином (UCB), а также UCB комплексами с медью в чувствительных областях центральной нервной системы. По-видимому, неонатальный гемолиз эритроцитов приводит к нефизиологическому выделению меди и железа из клеток, которые проходят через гематоэнцефалический барьер (ГЭБ) через кровоток. Кроме того, активные формы кислорода способствуют увеличению проницаемости ГЭБ, что создает опасный порочный круг в мозге новорожденных. В этой статье мы представляем два случая гипербилирубинемии новорожденных, которые указывают на потенциальные нейропротективные эффекты D-PA.
Ключевые слова: D-пеницилламин; медь; биллирубин; неврологическая дисфункция; ретинопатия новорожденных; аутизм.
Тушндеме
НЕОНАТАЛДЫ КЕЗЕИДЕГ1 Д-ПЕНИЦИЛЛАМИННЩ НЕЙРОПРОТЕКТОРЛЫКК ЭСЕРЛЕР1
Lajos Lakatos1*, Jan Aaseth2,3, Maryam Dadar4, Geir Bj0rklund5*
1 Педиатрия кафедрасы, медициналык факультет, Дебрецен университетi, Дебрецен, Венгрия;
2 Гылыми - зертету бeлiмi, Innlandet Hospital Trust, Брумунддал к-, Норвегия;
3 И.М. Сеченов атынд. Бiрiншi Мэскеу мемлекеттiк медицина университет (Университет им. Сеченова), Мэскеу к., Ресей
4 Рази вакцина жэне сары су гылыми - зерттеу институты, Ауыл шаруалшылык зерттеулерiн, бiлiмдi уйымдастыру жэне iлiмдi тарату (AREEO), Карадж к., Иран;
5 Тагамдык жэне экологиялык медицина бойынша Кецес (CONEM), Мо жэне Рана к., Норвегия
D-пеницилламин (D-PA) бастапщыда гемолитикалыщ аурулар немесе бауыр уридин-5'-дифосфо-глюкуроносил трансфераза (UDP-глюкуроносил трансферазась) ферменттерЫщ гемолитикальщ аурулардан туындаган неонаталдь гипербилирубинемияны емдеудегi ыщтимал артыщшылыщтарына байланысты щолданылды. Сол кезечде D-PA емiн щабылдаган шала туган балаларда ретинопатияныщ (РОП) кеп таралуы аныщталды. Кейiнiрек зерттеу Польша, Венгрия, А^Ш, Мексика жэне YндiстандаFы 8ртYрлi институттармен жYргiзiлдi. Препаратты щысща мерзiмдi немесе узащ мерзiмдi щолдану, уыттылыщты немесе тезбеушiлiктi тудырмады, D-PA тш ересек емделушiлерде щолданылFан дозалармен салысты^анда неонатальды кезечде жоFарыращ дозаларда да бертдк БалалардаFы билирубиннен туындаFан кейбiр неврологиялыщ дисфункциялар, оныщ iшiнде ROP коса алFанда жэне аутизм спектрЫщ бузылыстары, металлдарды жинащтаумен, байланбаFан билирубинмен (UCB) жэне орталыщ жYЙке жYЙес¡нщ сезiмтал аймащтарында мыс кешендерi бар UCB тудыруы мYмкiн. Эритроциттердщ неонатальды гемолизi щанщуйылуы арщылы гематоэнцефаликалыщ тосщауылынан (BBB) eтетiн щан жасушаларынан мыс пен темiрдщ физиологиялыщ емес белЫуЫе 8келедi. Содан басща, белсендi оттеп тYрлерi ГЭБ еткiзгiштiгiн арттырады, бул нэрестелер миында щауiптi щатерлi ше^бер жасайды. Осы мащалада бiз D-PA потенциалды нейропротективтi 8серлерiне керсететiн жа^а туылFандар гипербилирубинемияны 4 екi жаFдайын усынамыз.
Нег'1зг'1 свздер: D-пеницилламин; мыс; биллирубин; неврологиялык дисфункция; жаца туылгандар ретинопатиясы; аутизм.
Библиографическая ссылка:
Lajos Lakatos, Jan Aaseth, Maryam Dadar, Geir Bj0rklund Нейропротекторные эффекты Д - пеницилламина в неонатальном периоде // Наука и Здравоохранение. 2019. 5 (Т.21). С. 116-120.
Lajos Lakatos, Jan Aaseth, Maryam Dadar, Geir Bj0rklund Neuroprotective effects of D-Penicillamine in the neonatal period // Nauka i Zdravookhranenie [Science & Healthcare]. 2019, (Vol.21) 5, pp. 116-120.
Lajos Lakatos, Jan Aaseth, Maryam Dadar, Geir Bj0rklund Неонаталды кезечдеп Д-пеницилламиннщ нейропротекторльщ 8серлерi // Гылым жэне Денсаульщ са^тау. 2019. 5 (Т.21). Б. 116-120.
Introduction
Currently, 50% of pregnancies in the USA result in postnatal or prenatal mortality, considerable congenital disabilities, neurological developmental problems, or in other ways, chronically sick and unhealthy babies [7,28,9]. In recent years, the prevalence of immune reactive or neurotoxic conditions like attention deficit disorder (ADD), autism spectrum disorder (ASD), dyslexia, learning disabilities, as well as schizophrenia have increased rapidly [38,35,34]. In the organism, misplaced copper and iron ions catalyze the initiation and acceleration of the activity of oxygen radicals [31]. The interaction that exists between oxygen radicals and their target creates a free radical cascade. Free radicals attack and cause disruption of nearby cells, which additional will produce free radicals, and so on [30,23]. Reactive oxygen species and free radicals are drawn towards iron and copper ions [15,26], attack cells, disrupt cell membranes, neurotransmitters, neuroreceptors, and enzyme systems [32]. In particular,
neuro-systems are vulnerable to peroxidative destruction since they have a high level of fat insulate. To this concept, ASD, ROP, and bilirubin-induced neurologic dysfunction (BIND) are neurodevelopmental and neurodegenerative diseases of the immature brain due to accumulation of unconjugated bilirubin (UCB), UCB-copper complex (as prooxidant), and free metals, respectively, in relevant brain parts, including the basal ganglia. The chelator D-penicillamine (D-PA) is an a-amino acid metabolite of penicillin without antibiotic properties (Fig. 1). D-PA can contribute to healthy cells through the reduction of free radicals via the removal of metal ions (in particular iron and copper), which catalyzes lipid peroxidation [3,16].
Furthermore, heme oxygenase activity, the peroxidation of lipid in the membranes of red blood cells and hemolysis, as well as the activity of uridine 5'-diphospho-glucuronosyltransferase (UDP-glucuronosyltransferase) prior to and after D-PA treatment can be described as critical areas for bilirubin excretion and production [19]. The
peroxidation of lipids also has been evaluated being a membrane damage mechanism in many hemolyses due to red cell disorders [12]. The susceptibility of red blood cells to autooxidation is three times higher in newborn babies compared with adults [37]. Also, a significant reduction in the fluorescence detection of cell lipid extracts and the hemolysis can be achieved by the in vitro D-PA preincubation [17]. It may be an acceptable drug to interact as a binding agent with the copper for use to control the occurrence of icterus neonatorum [17]. Although the same accurate information has been known over the last decades, the complete mechanism of D-PA action is still unknown.
Fig. 1. The metal chelator D-penicillamine (dimethylcysteine, D-PA) is a metabolite of penicillin consisting a thiol, a carboxylic acid, and an amine.
We present two cases of neonatal hyperbilirubinemia from the Department of Pediatrics at Kenezy Gyula Hospital and Clinic in Debrecen, which indicate the potential neuroprotective effects of D-PA.
Case reports
Case 1.
The first patient was an ABO-incompatible preterm infant (birth weight: 2200 g.), who received treatment with D-PA during the neonatal time period [11]. Because of serious hemolysis, an early exchange transfusion was required, but not even this intervention was able to stop the rapid increase in the bilirubin level. At the beginning of the second exchange, the cardiopulmonary arrest occurred requiring resuscitation. At an extremely high bilirubin level (32.5 mg/dl) and with acute symptoms of bilirubin encephalopathy, the intravenous D-PA administration was started. After the first dose, a considerable fall of 6.5 mg/dl in the bilirubin level in four hours was observed, and due to the treatment, it was possible to observe that the hyperbilirubinemia gradually disappeared. Today, this patient is an opera singer and member of a famous German opera house. What makes this case even more remarkable is that neonatal hyperbilirubinemia frequently causes sensorineural hearing impairment.
Case 2.
It was cared for a term infant girl who was born at 39 weeks' gestation to a 24-year-old, blood group O, Rh-positive mother. The pregnancy was uncomplicated, and group A, an Rh-positive baby, weighed 3100 g. At 50 hours of age, the bilirubin level (Sebi) was 4l6 mmol/l
(24.3 mg/dl); the hemoglobin value was 130 g/l. The baby was transferred to the neonatal unit, and the physicians decided to perform an exchange transfusion. At the admission, the baby's parents, who were members of the Jehovah's Witnesses, requested written in the chart that blood not under any circumstances, should be administered. On the other hand, they authorized the application of alternative therapies, i.e., 300 mg D-PA per day (divided into three doses) orally administered for three days, intravenous fluids, recombinant human erythropoietin (rhEPO), and phototherapy. The treatment with rhEPO was started with on day seven as a subcutaneous injection (200 U/kg) and was until day 23, given every second day, supplemented with vitamin E, folic acid, and iron. For this infant with ABO-HDN, the clinical data are shown in Table 1. Interestingly, she also has an excellent voice. At 16 years old, she was the winner of a school song festival. Also, she is a very good student in mathematics.
Table 1.
Clinical data of the reported infant (case 2).
Postnatal Serum Hemoglobin Treatment
age bilirubin (pmol/l) (g/l)
50 hours 416=24.3 130 D-PA+PT
58 hours 354=20.7 D-PA+PT
76 hours 277=16.2 D-PA+PT
100 hours 233=13.6 115
Seven days 214=12.5 113 rhEPO
Nine days 95 rhEPO
12 days 87 rhEPO
15 days 98 rhEPO
20 days 101 rhEPO
25 days 120
Six months 125
Abbreviations: D-penicillamine (D-PA); physiotherapy (PT); recombinant human erythropoietin (rhEPO)
Discussion
Although many well-trained physicians have been practicing chelation in cases of neonatal hyperbilirubinemia also in Poland, and the USA [18,25,11,39,33], this therapeutic approach is still considered controversial. The use of D-PA as a copper chelator is accepted routinely for the treatment of Wilson's disease (WD), and it should then be initiated as soon as the disease is diagnosed, in many cases, in young children [14]. D-PA, as well as trientine, can reduce the copper content in the brain of experimental animals and in cases of WD, thereby preventing the development of severe neurological signs and symptoms [19, 8, 1].
Since D-PA is classified as an orphan drug by the U.S. Food and Drug Administration [13], intravenous D-PA is not sold in the normal drug market. Orphan drugs are pharmaceutical agents developed for the treatment of very rare medical conditions, which otherwise would not without support from the government been profitable to produce. These conditions are termed orphan diseases.
Already for more than two decades ago, it was known that the copper metabolism of fetuses is different from
adults and similar to WD [10]. This knowledge has led researchers to suggest that WD patients have an error in the change from the neonatal mode to the adult mechanism. Both in normal fetuses and in patients with WD, the biliary excretion of copper is considerable reduced, i.e., low plasma values of copper, as well as low or absent plasma concentration of caeruloplasmin [27].
Several heavy metal ions, in particular, iron and copper, have a crucial pathogenic role in neurodegenerative disorders, including BIND or other neonatal conditions, having an impact both on oxidative stress and the structure of proteins (misfolding) [4,5,6, 24]. A recently published long-term follow-up study [29] indicates that the administration of D-PA to newborn infants can give significant neuroprotection in severe cases of ROP and BIND. Also, oxidative stress and copper dyshomeostasis have been concerned with
neurodevelopmental/neurodegenerative disorders like ASD. It is considered that elevated copper levels may be an etiological factor in ASD [40,2,20,36,21,22]. In newborn babies, the high activity of heme oxygenase may reflect the enzyme-inducing actions of metals (in particular copper and iron), which are derived by the breakdown of fetal erythrocytes [22].
Conclusion
D-PA is the most common drug for the treatment of copper overload. Also, some preterm infants have been treated with D-PA for severe jaundice and to prevent retinopathy during the last 28-40 years by Hungarian neonatologists. D-PA also alleviates oxidative stress and acts as a powerful antioxidant. D-PA also can reveal neuroprotective effects in BIND, and ROP, and may act protectively against other neurodegenerative disorders. However, it should be taken into account that D-PA may give rise to side effects. Monitoring of blood count, liver function tests, and urinary protein are recommended because of possible adverse effects.
Disclosure statement
All authors have no conflicts of interest to disclose.
References:
1. Aaseth J. Experimental copper chelation: clinical implications // Erudite J Drugs. 2012;1:1-3.
2. Almandil N.B., Alkuroud D.N., AbdulAzeez S., Al Sulaiman A., Elaissari A., Borgio J.F. Environmental and genetic factors in autism spectrum disorders: Special emphasis on data from Arabian studies // Int J Environ Res Public Health. 2019;16(4):658.
3. Ayala A, Muñoz M.F., Arguelles S. Lipid peroxidation: production, metabolism, and signaling mechanisms of malondialdehyde and 4-hydroxy-2-nonenal // Oxid Med Cell Longev. 2014;2014.
4. Bj0rklund G. The role of zinc and copper in autism spectrum disorders // Acta Neurobiol Exp (Wars). 2013;73(2):225-36.
5. Bj0rklund G., Chartrand M. Nutritional and environmental influences on autism spectrum disorder // J Nutr Disorders The. 2016;6:e123.
6. Bj0rklund G., Saad K., Chirumbolo S, Kern J.K., Geier D.A., Geier M.R. et al. Immune dysfunction and
neuroinflammation in autism spectrum disorder // Acta Neurobiol Exp (Wars). 2016;76(4):257-68.
7. Brooks D., Asta K., Sturza J., Kebede B., Bekele D, Nigatu B. et al. Patient preferences for prenatal testing and termination of pregnancy for congenital anomalies and genetic diseases in Ethiopia // Prenat Diagn. 2019; 39(8):595-602.
8. Cao Y., Skaug M.A., Andersen O., Aaseth J. Chelation therapy in intoxications with mercury, lead and copper // J Trace Elem Med Biol. 2015;31:188-92.
9. Chen L., Wang W.-J., Auger N., Xiao L., Torrie J., McHugh N.G.-L. et al. Diabetes in pregnancy in associations with perinatal and postneonatal mortality in First Nations and non-Indigenous populations in Quebec, Canada: population-based linked birth cohort study // BMJ Open. 2019;9(4):e025084.
10. Chowrimootoo G., Scowcroft H., Seymour C.A. Caeruloplasmin isoforms in Wilson's disease in neonates // Archives of Disease in Childhood-Fetal and Neonatal Edition. 1998;79(3):F198-F201.
11. Christensen R., Alder S., Richards S., Lambert D., Schmutz N., Wiedmeier S. et al. D-Penicillamine administration and the incidence of retinopathy of prematurity // J Perinatol. 2007;27(2):103.
12. Goldstein B.D., Harber L.C. Erythropoietic protoporphyria: lipid peroxidation and red cell membrane damage associated with photohemolysis // J Clin Invest. 1972;51(4):892-902.
13. Hadjivasiliou A. Evaluate Pharma // Orphan Drug Report. 2014. 20.15.
14. Horn N., M0ller L.B., Nurchi V.M., Aaseth J. Chelating principles in Menkes and Wilson diseases: Choosing the right compounds in the right combinations at the right time // J Inorg Biochem. 2018.
15. Jomova K., Valko M. Advances in metal-induced oxidative stress and human disease // Toxicology. 2011;283(2-3):65-87.
16. Kandanapitiye M.S., Gunathilake C., Jaroniec M., Huang S.D. Biocompatible D-penicillamine conjugated Au nanoparticles: targeting intracellular free copper ions for detoxification. J Mater Chem B. 2015;3(27):5553-9.
17. Lakatos L., Balla G. D-Penicillamine in the neonatal period. LAP Lambert Academic Publishing. 2016.
18. Lakatos L., Kover B. Az ujszulottkori hyperbilirubinaemiak D-Penicillamin therapiaja. D-Penicillamine Therapy In Neonatal Hyperbilirubinaemias // A Preliminary Report. Orv Hetil (Hungarian J Med). 1974;115:307-11.
19. Lakatos L., Balla G., Pataki I. Copper-induced oxidative/nitrosative stress and excitoxicity in the neonatal period: neuroprotection with D-Penicillamine // Pediatr Dimens. 2017;2:1-6.
20. Lakatos L. Penicillamine-Preventing or. Curing" Autism Spectrum Disorders in the Neonatal Period. 2017:51-2.
21. Macedoni-Luksic M., Gosar D., Bj0rklund G., Orazem J., Kodric J., Lesnik-Musek P. et al. Levels of metals in the blood and specific porphyrins in the urine in children with autism spectrum disorders // Biol Trace Elem Res. 2015;163(1-2):2-10.
22. Maines M.D., Kappas A. Metals as regulators of heme metabolism // Science. 1977;198(4323) :1215-21
23. Martínez A., Reina M. Copper or free radical scavenger? // Computational and Theoretical Chemistry. 2017;1104:1-11.
24. Meguid N.A., Anwar M., Bj0rklund G., Hashish A., Chirumbolo S., Hemimi M. et al. Dietary adequacy of Egyptian children with autism spectrum disorder compared to healthy developing children // Metab Brain Dis. 2017;32(2):607-15.
25. Nagy A., Felszeghi E. Per os D-Penicillaminnal és fototerápiával sikeresen kezelt Rh-isoimmunisation // Gyermekgyógyászat. 2000;51:81-3.
26. Nimse S.B., Pal D. Free radicals, natural antioxidants, and their reaction mechanisms // Rsc Advances. 2015;5(35):27986-8006.
27. Ohrvik H., Aaseth J., Horn N. Orchestration of dynamic copper navigation-new and missing pieces // Metallomics. 2017;9(9):1204-29.
28. Pasupathy D., Denbow M., Rutherford M. Obstetricians RCo, Gynaecologists. The Combined Use of Ultrasound and Fetal Magnetic Resonance Imaging for a Comprehensive Fetal Neurological Assessment in Fetal Congenital Cardiac Defects: Scientific Impact Paper No. 60. // BJOG: An International Journal of Obstetrics & Gynaecology. 2019;126(7):e142-e51.
29. Pataki I., Balla G, Nagy A., Berkes A., Szolos A. Long-term follow up of patients treated with D-Penicillamine in the neonatal period // J Neonatal Biol. 2018;7(270):2167-0897.1000270.
30. Perrone S., Tataranno M.L., Stazzoni G., Buonocore G. Oxidative stress and free radicals related diseases of the newborn // Adv Biosci Biotechnol. 2012;3(07):1043
31. Perry G., Sayre L.M., Atwood C.S., Castellani R.J., Cash A.D., Rottkamp C.A. et al. The role of iron and copper in the aetiology of neurodegenerative disorders // CNS drugs. 2002;16(5):339-52.
32. Phaniendra A., Jestadi D.B., Periyasamy L. Free radicals: properties, sources, targets, and their implication
in various diseases // Indian journal of clinical biochemistry. 2015;30(1):11-26.
33. Qureshi M.J., Kumar M. D-Penicillamine for preventing retinopathy of prematurity in preterm infants // Cochrane Database Syst Rev. 2013(9). https://doi.org/10.1002/14651858.CD001073.pub2
34. Rohlman D.S., Ismail A., Bonner M.R., Rasoul G.A., Hendy O., Dickey L.O. et al. Occupational pesticide exposure and symptoms of attention deficit hyperactivity disorder in adolescent pesticide applicators in Egypt // Neuro Toxicology. 2019;74:1-6.
35. Sirivichayakul S., Kanchanatawan B., Thika S., Carvalho A.F., Maes M. A New Schizophrenia Model: Immune Activation is Associated with the Induction of Different Neurotoxic Products which Together Determine Memory Impairments and Schizophrenia Symptom Dimensions // CNS Neurol Disord Drug Targets. 2019;18(2):124-40.
36. Skalny A.V., Simashkova N.V., Klyushnik T.P., Grabeklis A.R., Bj0rklund G., Skalnaya M.G. et al. Hair toxic and essential trace elements in children with autism spectrum disorder // Metab Brain Dis. 2017;32(1):195-202.
37. Stocks J., Offerman E., Modell C., Dormandy T. The susceptibility to autoxidation of human red cell lipids in health and disease // Br J Haematol. 1972;23(6):713-24.
38. Strunecka A, Strunecky O. Chronic Fluoride Exposure and the Risk of Autism Spectrum Disorder // Int. J Environ Res Public Health. 2019;16(18):3431.
39. Tandon M., Dutta S., Dogra M.R., Gupta A. Oral D-penicillamine for the prevention of retinopathy of prematurity in very low birth weight infants: a randomized, placebo-controlled trial // Acta P^diatrica. 2010;99(9):1324-8.
40. Walker L.R., Rattigan M., Canterino J. A case of isolated elevated copper levels during pregnancy // J. Pregnancy. 2011;2011.
*Corresponding authors:
Lajos Lakatos: Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary. Postal address: 4032 Debrecen, Hungary, Nagyerdei krt. 95. Phone: +36 52 411600/56288 Email: [email protected]
Geir Bj0rklund - Council for Nutritional and Environmental Medicine Toften 24, 8610 Mo i Rana, Norway E-mail: [email protected]
