The study objectives were to measure the concentrations of albumin, prealbumin and transferrin in amniotic fluid (AF), and to establish if these concentrations were associated with infant birth weight (BW). At St Mary's Hospital (Montreal, Quebec), 294 AF samples were collected from mothers undergoing routine amniocentesis (12-19 weeks gestation). Exclusion criteria included subjects having gestational diabetes, multiple births or fetal genetic abnormalities. AF samples were analyzed by capillary electrophoresis (CE) at 190 nm. Analysis of variance and multiple linear regressions were performed. AF prealbumin could not be detected by CE. However, ANCOVA showed that transferrin was different among BW categories. Multiple regressions showed the parameter estimates for transferrin and albumin were negative, but neither was associated with BW in our study population. In contrast, transferrin was negatively associated with BW in our LBW infants. Our study shows that 2nd trimester AF transferrin may emerge as a biomarker for poor in-utero growth.

Diss. - Columbia Univ. / Description based on print version record.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2010. / Title from title screen (site viewed July 8, 2010). PDF text: xiv, 323 p. : ill. (some col.) ; 11 Mb. UMI publication number: AAT 3398186. Includes bibliographical references. Also available in microfilm and microfiche formats.

A single column cation exchange method was developed which allowed simultaneous recovery of lysozyme and avidin from undiluted egg white using a unique elution sequence which involved accumulation of avidin on the column through several cycles of egg white application and lysozyme elution. Lysozyme was recovered with higher yields than reported for the isoelectric precipitation methods often used in the industry (86% vs 60 - 80%) and in high purity. Avidin recovery was also as good or better than that of previously reported ion exchange methods (74 - 80% vs 17 -80%). The purity of the avidin fraction (up to 40.9%) was superior to other reported primary avidin fractions. Avidin was shown to have a greater potential for both electrostatic and hydrophobic interactions with Duolite C-464 than lysozyme but under the conditions of this separation, electrostatic interactions were dominant. Secondary purification of avidin by carboxymethyl celluose cation exchange (CMC), gel filtration, metal chelate interaction chromatography (MCIC), aliphatic hydrophobic interaction chromatography (HIC), and Phenyl-Sepharose interaction chromatography (PSIC) each resulted in considerable increase in avidin purity. In terms of resin capacity, yields, and avidin purity however, CMC ion exchange was superior. A comparison of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) andnative protein electrophoresis profiles gave clear evidence of protein - protein interaction between avidin and lysozyme in partially purified avidin preparations. This interaction may also occur between the native proteins in the egg white, but has not been demonstrated with certainty. The molar ratio of avidin to available biotin binding sites was estimated by 5 methods. For highly purified avidin samples the hydroxy azo benzoic acid (HABA) method proposed by Green (1965) was superior. A new method, utilizing an immobilized biotin column, which did not require extensive purification of avidin was found to give similar results. Finally, a highly sensitive assay of proteins bound to nitrocellulose membranes was developed which was capable of quantifying as little as 0.12 µg of protein. Membrane bound proteins were labeled with peroxidase via a biotin - avidin linkage as previously reported and bound peroxidase activity was related to initial protein content. The method was applicable to determination of the relative concentrations of different protein bands on Western blots of electrophoresis gels. / Land and Food Systems, Faculty of / Graduate

Hypoalbuminaemia is an essential accompaniment of protein malnutrition. Yet the level of plasma albumin is usually regarded as a relatively crude reflection of a patient's nutritional status, reduction occurring only after prolonged or severe inadequacy of dietary protein. Brock recognized that a marginal degree of hypoalbuminaemia might be evidence of impending or early deficiency, and suggested that minor grades of "protein subnutrition" could conceivably exist with serum albumin levels still within the normal range. The work reported in this thesis developed originally out of an attempt to explore this possibility, and to characterize some of the changes in albumin metabolism that followed mild or early experimental protein deprivation in man and rabbits. Dynamic studies using albumin labelled with radioactive iodine revealed evidence of early adaptational changes, possibly occurring before alteration in the plasma albumin levels. While these studies shed some light on the response of albumin metabolism to experimental depletion, they failed to provide the hoped-for means by which subclinical protein malnutrition could be detected. From this work, however, it was but a short conceptual jump to the general problem of albumin homeostasis, a consideration of which forms the basis of this thesis. The first approach was a study of changes in albumin synthesis and catabolism in rabbits following limitation of dietary protein intake. Adaptive responses were then investigated in animals, provided with normal protein diets, after protein depletion induced by an alternative method - plasmapheresis - and, finally, after intravenous infusion of albumin solutions. Based on these and reported results, a tentative hypothesis has been adduced to account for the body's adaptation to variation in the plasma albumin pool, brought about by experimental manipulation or occurring spontaneously in disease.

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