Metabolism newborns

The second method for mixture analysis is the use of specialized software together with spectral databases. We have developed a mixture analysis program AMIX for one- and multidimensional spectra. The most important present applications are the field of combinatorial chemistry and toxicity screening of medical preparations in the pharmaceutical industry. An important medical application is screening of newborn infants for inborn metabolic errors. 

Bradycardia Bradycardia is a slow heart rate (60 beats per minute or slower) that does not meet the body s metabolic demands. Symptoms of bradycardia include dizziness, extreme fatigue, shortness of breath, or fainting spells. This can be compared to tachycardia, which is an extremely rapid heart rate, usually signified by a pulse of over 100 beats per minute. Adults usually have a resting heart rate of 70-80 beats per minute, although well-trained athletes can have resting rates in the 50 s or 60 s. Newborn babies have a normal heart rate of 120-160 beats per minute. A slowed heart rate can lead to a variety of other problems. First aid treatment may include administration of oxygen. 

When the newborn population Is examined It Is found that between 2 and 4% of Individuals, depending on how the figures are calculated, have some type of birth defect which Is considered to be genetic In origin (8,9) The term "birth defect" Is used In a general sense and encompasses all types of structural, metabolic, and other abnormalities which derive from genetic or other prenatal causes. The birth defects detected postnatally represent only a small fraction of the totality of abnormalities which result from genetic aberrations, but most of the latter result In early spontaneous abortions... 

Screening for the numerous disease of genetic origin on newborns will be expanded so that eventually a battery of tests will be utilized for the determination of the erythrocyte abnormalities and abnormalities of intermediate metabolism. 

As with urine, saliva (spumm) is easy to collect. The levels of protein and lipids in saliva or spumm are low (compared to blood samples). These matrices are viscous, which is why extraction efficiency of xenobioties amoimts to only 5 to 9%. By acidifying the samples, extraction efficiencies are improved as the samples are clarified, and proteinaceous material and cellular debris are precipitated and removed. Some xenobioties and their metabohtes are expressed in hair. Hair is an ideal matrix for extraction of analytes to nonpolar phases, especially when the parent xenobioties are extensively metabolized and often nondetectable in other tissues (parent molecules of xenobioties are usually less polar than metabolites). Hair is a popular target for forensic purposes and to monitor drug compliance and abuse. Human milk may be an indicator of exposure of a newborn to compounds to which the mother has been previously exposed. The main components of human milk are water (88%), proteins (3%), lipids (3%), and carbohydrates in the form of lactose (6%). At present, increasing attention is devoted to the determination of xenobioties in breath. This matrix, however, contains only volatile substances, whose analysis is not related to PLC applications. 

A few studies have reported associations between prenatal lead exposure and changes in heme metabolism. In a study of 294 mother-infant pairs, Haas et al. (1972) reported mean PbB levels of 16.98 pg/dL for mothers and 14.98 pg/dL for newborns. Infant PbB levels and ALA-U were positively correlated. The authors, however, did not report the levels of ALA-secretion in infants and mothers with no lead exposure. In pregnant urban women (Kuhnert et al. 1977), cord erythrocyte lead levels ranged... 

The urea cycle is essential for the detoxification of ammonia 678 Urea cycle defects cause a variety of clinical syndromes, including a metabolic crisis in the newborn infant 679 Urea cycle defects sometimes result from the congenital absence of a transporter for an enzyme or amino acid involved in the urea cycle 680 Successful management of urea cycle defects involves a low-protein diet to minimize ammonia production as well as medications that enable the excretion of ammonia nitrogen in forms other than urea 680... 

Urea cycle defects cause a variety of clinical syndromes, including a metabolic crisis in the newborn infant. 

Bakka, A. and M. Webb. 1981. Metabolism of zinc and copper in the neonate changes in the concentrations and contents of thionein-bound Zn and Cu with age in the livers of the newborn of various mammalian species. Biochem. Pharmacol. 30 721-725. 

Nickel is considered essential to animals because it is present in the fetus or newborn, is homeostatically regulated, the metabolic pool of nickel is specifically influenced by hormonal substances or pathologic processes, certain metalloproteins contain nickel, and because nickel deficiency has been induced experimentally in certain species of birds and animals (NAS 1975 USPHS 1977 Kirchgessner and Schnegg 1980). In general, the nickel deficiency syndrome can be cured or prevented by trace amounts of nickel (NAS 1975). However, nickel administration may not be successful in reversing all abnormalities produced by nickel deprivation (USPHS 1977). 

This in fact is what happened. Tandem MS has clearly been shown to be the only technology to screen for disorders of fatty acid oxidation and could also detect many disorders of organic acid metabolism. Tandem MS has the ability to detect both compound classes (amino acids and acylcarnitines) and after demonstrating that both classes could be prepared in the same manner, the MS/MS analysis of blood spots for newborn screening applications was born. 

The galactose-l-phosphate uridyl transferase pathway is by far the most important in galactose metabolism it accounts for about 5/6 of the total galactose metabolized in mammals. It is less active in the newborn than in the adult, e.g., the liver of newborn rats has only 1/5 the adult amount of galactose-l-phosphate uridyl transferase per milligram of protein (13). 

Koeberl DD, Young SP, Gregersen NS, Vockley J, Smith WE, Benjamin DK Jr, An Y, Weavil SD, Chaing SH, Bah D, McDonald MT, Kishnani PS, Chen YT, Millington DS. Rare disorders of metabolism with elevated butyryl- and isobutyryl-carnitine detected by tandem mass spectrometry newborn screening. Pediatr Res. 2003 Aug 54(2) 219-23. Epub 2003 May 7. PubMed citation... 

A much more serious genetic disease, first described by Foiling in 1934, is phenylketonuria. Here the disturbance in phenylalanine metabolism is due to an autosomal recessive deficiency in liver phenylalanine hydroxylase (Jervis, 1954) which normally converts significant amounts of phenylalanine to tyrosine. Phenylalanine can therefore only be metabolized to phenylpyruvate and other derivatives, a route which is inadequate to dispose of all the phenylalanine in the diet. The amino acid and phenylpyruvate therefore accummulate. The condition is characterized by serious mental retardation, for reasons which are unknown. By the early 1950s it was found that if the condition is diagnosed at birth and amounts of phenylalanine in the diet immediately and permamently reduced, mental retardation can be minimized. The defect is shown only in liver and is not detectable in amniotic fluid cells nor in fibroblasts. A very sensitive bacterial assay has therefore been developed for routine screening of phenylalanine levels in body fluids in newborn babies. 

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