Amino acids, Amniotic fluid

Agilent ChemStation software, 29-31, 33 Alkylquinaxolines, in Phodopus roborovskii, 19 Allomones, 13 2-Aminoacetophenon, 155 2-Amino-7-hydroxy-5,5-dimethyl-4-thiaheptanoic acid, see Felinine Amniotic fluid, odour of, 194 Amphetamine, 266... 

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. 

Braida L, Crovella S, Boniotto M, et al (2001) A rapid and quantitative mass spectrometry method for determining the concentration of acylcarnitines and amino acids in amniotic fluid. Prenat Diagn 21 543-546... 

Organic acids have also been studied in plasma, e.g. [341], amniotic fluid [363] and CSF [364]. Several other classes of compounds have received attention in profile analysis, most notably steroids (see above under Steroids) and amino acids [340,341]. 

Adriaenssens et al. (A3) have described a simple screening method for the study of amino acids in tissues using frozen slices. Efron (ElO) has described methods for the extraction of free amino acids from urine, plasma, spinal fluid, sweat, and cellular material. Saifer (SI) has made a comparative study of seven published procedures for extracting free amino acids from brain tissue and concluded that perchloric acid extraction is the simplest and gives the most consistent results.With minor modifications this extraction method can be applied to amniotic fluid (S5), brain and other tissues (All, SI), plasma, urine, cerebrospinal fluid, etc. 

Quantitative Levels op Free Amino Acids in Normal Human Amniotic Fluid, Blood Plasma, Urine, and Cerebrospinal Fluid (CSF)... 

Where no effective treatment exists at present for some inborn errors of metabolism, and where these disorders are associated with severe illness, mental retardation, or early death, the prenatal diagnosis of the diseased fetus by amniotic fluid enzyme analysis is now possible (MIO, Mil, M12). These new developments in the field of transabdominal amniocentesis, coupled with more liberal abortion laws, can serve to reassure families with a previous history of a fatal disease that their offspring will be physiologically normal. As applied to the field of amino acid disorders, enzyme analysis of cultured amniotic fluid cells has been used to diagnosis potential cases of homocystinuria (Fig. 51) and... 

L8. Levy, H. L., and Montag, P. P., Free amino acids in human amniotic fluid. A quantitative study by ion-exchange chromatography. Pediat. Res. 3, 113-120 (1969). 

Saifer, A., A Zary, E. A., Valenti, C. and Schneck, L., Quantitative cation-exchange chromatographic analysis of free amino acids in human amniotic fluid collected during early pregnancy. Clin. Chem. 16, 891-895 (1970). 

Alanine glutamate Aldioxa Aleuritic acid Aluminum capryloyl hydrolyzed collagen Aluminum undecylenoyl collagen amino acids Ammonium dimethicone copolyol sulfate Ammonium glycyrrhizate Ammonium hydrolyzed collagen Amniotic fluid AMP-isostearoyl gelatin/keratin amino acids/lysine hydroxypropyltrimonium chloride AMP-isostearoyl hydrolyzed soy protein AMP isostearoyl hydrolyzed wheat protein Amyl... 

Gas Chromatographic Analysis of Concentrations of Amino Acids in Amniotic Fluid from Early, Middle, and Late Periods of Human Gestation... 

Gas Chromatography-Mass Spectrometric Analysis of Organic Acids and Amino Acids in Amniotic Fluid Koenshu - lyo Masu Kenkyukai 3 137-142 (1978) GA 92 193773k... 

In the amniotic fluid there is a decreasing concentration of most amino acids with increasing gastational age. The maximum rate of decrease occurs between the twenty-second and the twenty-fourth week of gestation (0 Neill t l., 1971 Thomas t a l., 1971). 

For our studies, an amino acid solution was prepared which reflected what is made available to the fetus. The solution contained 6.2 gm N/1 or 5.36 gm of -amino nitrogen. Since the nitrogen requirements of premature infants range between 0.5 and 0.7 gm N per kg body weight (Snyderman, 1970), the daily needs for nitrogen of a fetus weighing 2 kg can be covered by 200 ml of this solution. For our studies, 250 ml of this solution were slowly instilled into the amniotic fluid. 

At specific intervals, amniotic fluid was aspirated for column chromatography. In addition, total nitrogen, -amino nitrogen, urea, uric acid, creatinine as well as certain enzymes were also determined. 

The amino acids given intraamnially disappeared from the amniotic fluid at an unexpectedly rapid and rather uniform rate. 

Fig. 1, Changes in the amniotic fluid concentration of amino acids given intra-amniotically.

Figure 1 shows the decreasing concentration of amino acids from the amniotic fluid as a function of time. After two hours, approximately two thirds of the amino acids given intraamnially disappeared thereafter the rate of removal plateaued. After twenty four hours, the values returned to the baseline. The rapid disappearance of the amino acids from the amniotic fluid is difficult to explain. 

Amniotic fluid has limited value in prenatal diagnosis for the aminoacid-opathies. Unlike the organic acid disorders, in most amino acid disorders the metabolites do not accumulate before birth. Abnormal amino acid patterns in amniotic fluid have only been found in two of the urea cycle disorders, namely argininosuccinate lyase deficiency (argininosuccinic acidemia) and argininosuccinate synthetase deficiency (citrullinemia). 

For prenatal diagnosis, amniotic fluid can be used to identify acylcarni-tines characteristic of certain branched-chain amino acid disorders. Cultured amniocytes or chorionic villous cells can be used with in-vitro substrate loading for diagnosis of fatty acid and branched-chain amino acid disorders as described earlier for fibroblasts [13]. 

Glycodelin-A (GdA), is a human amniotic fluid-derived glycoprotein that has potent contraceptive and immunosuppressive activities. GdA has 162 amino acids and there are three potential A-linked glycosylation sites at Asn-28, Asn-63 and Asn-85. Together LC-ES-MS and FAB-MS gave sufficient data to define the site occupancy and the sequences of the A-glycans present on GdA. 

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