Project description:BackgroundPhenylalanine is an indispensable amino acid and, via tyrosine, is the precursor for the neurotransmitters dopamine, norepinephrine, and epinephrine. Currently, dietary requirements for phenylalanine during pregnancy are unknown.ObjectivesThis study's aim was to determine phenylalanine requirements (in the presence of excess tyrosine) during early and late gestation using direct amino acid oxidation (DAAO; with l-[1-13C]phenylalanine) and indicator amino acid oxidation (IAAO; with l-[1-13C]leucine).MethodsTwenty-three healthy women (age: 30.4 ± 3.1 y, mean ± SD) were studied at a range of phenylalanine intakes (5.5-30.5 mg · kg-1 · d-1 in early and late pregnancy using DAAO, and 2.5-30.5 mg · kg-1 · d-1 in late pregnancy using IAAO) for a total of 76 study days. Test intakes were provided as 8 isocaloric and isonitrogenous meals with 1.5 g · kg-1 · d-1 protein and energy at 1.7 times the measured resting energy expenditure. Breath samples were analyzed on an isotope ratio mass spectrometer for 13C enrichment. Phenylalanine requirement was determined using a 2-phase linear regression crossover model to identify a breakpoint in 13CO2 production (representing the mean requirement) in response to phenylalanine intakes.ResultsPhenylalanine requirement during early pregnancy was determined to be 15 mg · kg-1 · d-1 (95% CI: 10.4, 19.9 mg · kg-1 · d-1); during late pregnancy, it was determined to be 21 mg · kg-1 · d-1 by DAAO (95% CI: 17.4, 24.7 mg · kg-1 · d-1) and IAAO (95% CI: 10.5, 32.2 mg · kg-1 · d-1).ConclusionsOur results suggest a higher requirement (40%) for phenylalanine during late pregnancy than during early pregnancy. Moreover, the early pregnancy requirements are higher than the previous adult male requirement (9.1 mg · kg-1 · d-1; 95% CI: 4.6, 13.6 mg · kg-1 · d-1), although the 95% CIs overlap. Both DAAO and IAAO methods provided similar breakpoints in late pregnancy, showing that the DAAO method was appropriate even though low phenylalanine intakes could not be tested. These results have potential implications for gestation stage-specific dietary phenylalanine recommendations in future.This trial was registered at clinicaltrials.gov as NCT02669381.

Project description:Background: Standard Guthrie cards have been widely used to collect blood samples from neonates for newborn screening programs, and to a lesser extent, from normal controls and patients in research studies. Ease of blood collection (small quantity and less pain), transportation, and storage are the advantages of using these cards. It is believed that RNA obtained from these samples is of low quantity and degraded quality. However, we recently discovered that approximately 3,500 expressed genes can be detected from blood spot samples using in-house made, low resolution cDNA microarrays. Here, we established a new and improved methodology to acquire gene expression profiles from blood spot cards using commercially-available high resolution microarrays. We determined the optimal number of blood spot punches required for maximal RNA extraction, eliminated uses of trizol and chloroform for RNA extraction by using a modified protocol of the illustra Mini Spin Kit from GE-Whatm an, concentrated the quantity of RNA templates before amplification, improved amplification efficiency using the new Ribo-SPIA technology in WT-Ovation Pico System (WT-Pico) by NuGEN, before the samples were hybridized onto 4x44K whole human genome gene expression microarrays from Agilent. Nine dried blood spot samples were collected from a control population and stored at ~ -80 °C between 6 months to 2 years. High quality RNA was extracted from the buffy coat of the same individuals as a reference and processed using the standard Agilent microarray procedure. Commercially-available brain RNA was used as a positive control in both standard and new procedures for microarrays. Results: Three 3-mm punches produced the highest yield of total RNA using the non-trizol extraction method. Three to six nanogram per microliter of RNA can be concentrated and is sufficient to be amplified using the WT-Pico. Approximately 9,000 expressed genes can be detected after normalization and background correction of the microarray data. Conclusion: Genome-wide gene expression profile can be obtained from archived dried blood spot samples. Our new and improved methodology will add value to the perception of utilizing archival Guthrie cards eg. neonatal blood spot cards as unique biospecimens for molecular genomics and diagnostic studies of perinatal diseases such as pediatric cancers. Keywords: Gene Expression experiment

Project description:Background: Standard Guthrie cards have been widely used to collect blood samples from neonates for newborn screening programs, and to a lesser extent, from normal controls and patients in research studies. Ease of blood collection (small quantity and less pain), transportation, and storage are the advantages of using these cards. It is believed that RNA obtained from these samples is of low quantity and degraded quality. However, we recently discovered that approximately 3,500 expressed genes can be detected from blood spot samples using in-house made, low resolution cDNA microarrays. Here, we established a new and improved methodology to acquire gene expression profiles from blood spot cards using commercially-available high resolution microarrays. We determined the optimal number of blood spot punches required for maximal RNA extraction, eliminated uses of trizol and chloroform for RNA extraction by using a modified protocol of the illustra Mini Spin Kit from GE-Whatm an, concentrated the quantity of RNA templates before amplification, improved amplification efficiency using the new Ribo-SPIA technology in WT-Ovation Pico System (WT-Pico) by NuGEN, before the samples were hybridized onto 4x44K whole human genome gene expression microarrays from Agilent. Nine dried blood spot samples were collected from a control population and stored at ~ -80 °C between 6 months to 2 years. High quality RNA was extracted from the buffy coat of the same individuals as a reference and processed using the standard Agilent microarray procedure. Commercially-available brain RNA was used as a positive control in both standard and new procedures for microarrays. Results: Three 3-mm punches produced the highest yield of total RNA using the non-trizol extraction method. Three to six nanogram per microliter of RNA can be concentrated and is sufficient to be amplified using the WT-Pico. Approximately 9,000 expressed genes can be detected after normalization and background correction of the microarray data. Conclusion: Genome-wide gene expression profile can be obtained from archived dried blood spot samples. Our new and improved methodology will add value to the perception of utilizing archival Guthrie cards eg. neonatal blood spot cards as unique biospecimens for molecular genomics and diagnostic studies of perinatal diseases such as pediatric cancers. Keywords: Gene Expression experiment Archival guthrie blood-spot cards may contain valuable data for epidemiological or other studies. Showing microarray data from guthrie blood-spot cards

Dataset Information

Phenylalanine and tyrosine measurements across gestation by tandem mass spectrometer on dried blood spot cards from normal pregnant women.

Publications

Phenylalanine and tyrosine measurements across gestation by tandem mass spectrometer on dried blood spot cards from normal pregnant women.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets