Determination of 2'-Fucosyllactose and Lacto-N-neotetraose in Infant Formula.

Human milk oligosaccharides (HMO) are the third most abundant solid component of human milk. It is likely that they are responsible for at least some of the benefits experienced by breast-fed infants. Until recently HMO were absent from infant formula, but 2'-fucosyllactose (2'-FL) and lacto-N-neoteraose (LNnT) have recently become available as ingredients. The development of formula containing these HMO and the quality control of such formula require suitable methods for the accurate determination of the HMO. We developed two different approaches for analysis of 2'-FL and LNnT in formula; high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and hydrophilic interaction liquid chromatography with fluorescence detection (HILIC-FLD). In lab trials using blank formula spiked with the two oligosaccharides, both approaches worked well with recoveries of 94⁻111% (HPAEC-PAD) and 94⁻104% (HILIC-FLD) and RSD (iR) of 2.1⁻7.9% (HPAEC-PAD) and 2.0⁻7.4% (HILIC-FLD). However, when applied to products produced in a pilot plant, the HPAEC-PAD approach sometimes delivered results below those expected from the addition rate of the ingredients. We hypothesize that the oligosaccharides interact with the formula matrix during the production process and, during sample preparation for HPAEC-PAD those interactions have not been broken. The conditions required for labeling the HMO for detection by the FLD apparently disrupt those interactions, and result in improved recoveries. It is likely that both analytical approaches are appropriate if a suitable extraction process is used to recover the HMO.

Seronegative polyarthritis revealing antisynthetase syndrome: a multicentre study of 40 patients.

OBJECTIVE: The aim of this study was to determine the frequency and characteristics of antisynthetase syndrome (ASS) revealed by polyarthritis. METHODS: First we conducted a retrospective single-centre study to assess the frequency of ASS patients who presented with polyarthritis without pulmonary and/or muscle symptoms. Secondly, we conducted a larger, multicentre study in order to describe the clinical characteristics of these patients. Exclusion criteria were the presence of RF, the presence of ACPA and overlap with another CTD. RESULTS: In the single-centre study, polyarthritis was the first manifestation in 12 of 45 ASS patients (27%). An additional 28 patients were collected for the multicentre study, resulting in a total population of 40 ASS patients who presented with polyarthritis. The mean delay from polyarthritis onset to ASS diagnosis was 27 months (s.d. 40). Pulmonary and muscle symptoms were uncommon at ASS diagnosis (40% and 32.5%, respectively) and were dramatically delayed [mean delay after polyarthritis onset of 41 months (s.d. 53) and 21 months (s.d. 14), respectively]. Mechanic's hands and cutaneous signs of DM occurred in 25% and 22.5%, respectively, with a mean delay of 10 months (s.d. 10) and 31 months (s.d. 21), respectively. When present (32%), RP was the earliest non-articular manifestation [mean delay 3 months (s.d. 23) after polyarthritis onset]. On HEp-2 cells, antinuclear and/or cytoplasmic fluorescence was found in 70% of cases, with specificity for various anti-aminoacyl tRNA synthetase (anti-ARS) antibodies. CONCLUSION: ASS may be revealed by polyarthritis. To decrease the delay in diagnosis of ASS, pulmonary and muscle symptoms and anti-ARS antibodies might usefully be searched for in seronegative polyarthritis patients, especially in those with RP.

Determination of sialic acids in milks and milk-based products.

Sialic acids are becoming recognized as important components of milk-based products for infants and young children. As such, many companies now label the sialic acid content of their products. To control the labeling, suitable methods are required for this analysis. The objective of this work was to set up a rapid and sensitive method for the determination of the two most commonly occurring sialic acids, N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), using high-performance liquid chromatography (HPLC). The sialic acids were released from their parent oligosaccharides, glycoproteins, or glycolipids by mild acid hydrolysis using formic acid. They were then derivatized using 1,2-diamino-4,5-methylenedioxybenzene (DMB) and subsequently separated on a Zorbax SB-Aq Rapid Resolution column in less than 2 min. The method developed was validated on various milk-based products and ingredients containing sialic acid at levels from 0.3 to 900 mg/100 g. Spiking experiments indicate that the sialic acid recoveries ranged from 87% to 108%. The expanded measurement uncertainty was typically below 15% for Neu5Gc and typically below 10% for Neu5Ac or the sum of the sialic acids, with a few exceptions. The proposed method is fast, specific, and easy to set up for compliance analysis in a routine laboratory.

Determination of ß -Galactooligosaccharides by Liquid Chromatography.

Beta-galactooligosaccharides (GOS) are oligosaccharides normally produced industrially by transgalactosylation of lactose. They are also present naturally in the milk of many animals including humans and cows. GOS are thought to be good for health, being potential prebiotic fibres, and are increasingly added to food products. In order to control the GOS content of products, the AOAC official method 2001.02 was developed. However, the method has some shortcomings and in particular is unsuited to the analysis of products containing high levels of lactose such as infant formula. To overcome this problem, we developed a new method for application to infant formula and tested it on various GOS ingredients as well as infant formulae. When applied to GOS ingredients the results of the new method compare well with those of the official AOAC method, typically giving results in the range 90-110% of those of the official method and having an expanded measurement uncertainty of less than 15%. For three products, the results were outside this range (recoveries of 80-120% and expended measurement uncertainties up to 20%). When applied to the analysis of infant formula, recoveries were in the range of 92-102% and the expanded measurement uncertainties were between 4.2 and 11%.