Genetic analyses of gustation in the fowl

Preferences towards quinine sulfate (QS) and dextrose (DEX) were tested in purelines and reciprocal crosses of two lines of chickens that had undergone 22 generations of selection for high and low juvenile body weight. Parental line-F₁ comparisons provided evidence for non-additive genetic variation for hedonic sensitivity towards QS and DEX, though in opposite directions. Additive genetic variation appeared to influence the preference ratios for both stimuli at super-threshold concentrations. These results are discussed with regard to their evolutionary implications.     

Monoclonal antibodies to three distinct epitopes on human IgE: their use for determination of allergen-specific IgE

Three different monoclonal antibodies (MAb) against human immunoglobulin E have been obtained which specifically bind to human myeloma and polyclonal IgE. The antibodies showed high avidities for soluble IgE (0.7 X 10(9) to 3.3 X 10(9) M-1). These MAb defined three distinct epitopes on IgE. A mixture of these antibodies in combination with an 125I-labelled anti-mouse Kappa chain MAb has been used to measure allergen-specific IgE. This determination was performed by a solid-phase radioimmunoassay using allergen extracts coated to either chemically activated paper discs or to polyvinyl chloride wells. This method is 4-10 times more sensitive than other previously reported procedures. A similar technique has also been applied to detect individual allergens in immunoblots of allergen extracts.     

Localization of the disulfide bridges of human histocompatibility antigens.

Both papain-solubilized and detergent-solubilized human histocompatibility antigens have been treated with NTCB (2-nitro-5-thiocyanatobenzoic acid) which cleaves these molecules at cysteine residues. A study of the fragment produced has made it possible to deduce the size and location of the two disulfide loops in these molecules. The sizes of the two loops in HLA-B7 and in the mixture HLA-B7 + 12 are about 5100 and 6600 daltons, a size similar to that of the disulfide loops found in immunoglobulins. The disulfide loops in HLA-A2 may be smaller in size. The two loops are located in middle regions of these molecules; neither the N-terminal nor the C-terminal regions contain disulfide loops.     

Labeling of cells with ferumoxides-protamine sulfate complexes does not inhibit function or differentiation capacity of hematopoietic or mesenchymal stem cells

Two FDA-approved agents, ferumoxides (Feridex), a suspension of superparamagnetic iron oxide (SPIO) nanoparticles and protamine sulfate, a drug used to reverse heparin anticoagulation, can be complexed and used to label cells magnetically ex vivo. Labeling stem cells with ferumoxides-protamine sulfate (FePro) complexes allows for non-invasive monitoring by MRI. However, in order for stem cell trials or therapies to be effective, this labeling technique must not inhibit the ability of cells to differentiate. In this study, we examined the effect of FePro labeling on stem cell differentiation. Viability, phenotypic expression and differential capacity of FePro labeled CD34 + hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC) were compared with unlabeled control cells. Colony-forming unit (CFU) assays showed that the capacity to differentiate was equivalent for labeled and unlabeled HSC. Furthermore, labeling did not alter expression of surface phenotypic markers (CD34, CD31, CXCR4, CD20, CD3 and CD14) on HSC, as measured by flow cytometry. SDF-1-induced HSC migration and HSC differentiation to dendritic cells were also unaffected by FePro labeling. Both FePro-labeled and unlabeled MSC were cultured in chondrogenesis-inducing conditions. Alcian blue staining for proteoglycans revealed similar chondrogenic differentiation for both FePro-labeled and unlabeled cells. Furthermore, collagen X proteins, indicators of cartilage formation, were detected at similar levels in both labeled and unlabeled cell pellets. Prussian blue staining confirmed that cells in labeled pellets contained iron oxide, whereas cells in unlabeled pellets did not. It is concluded that FePro labeling does not alter the function or differentiation capacity of HSC and MSC. These data increase confidence that MRI studies of FePro-labeled HSC or MSC will provide an accurate representation of in vivo trafficking of unlabeled cells.     

Metachromatic leukodystrophy caused by a partial cerebroside sulfatase defect

A patient with neuropathy and myopathy since infancy but whose neuropathy had been stable for a number of years showed a profound deficiency of arylsulfatase A in leukocytes and urine. Urine contained material that stained metachromatically and cochromatographed with cerebroside sulfate. In contrast, cultured fibroblasts contained about 10-20% of normal arylsulfatase A with properties identical to properties of normal fibroblast enzyme, except that it showed no cerebroside sulfatase activity. Growing fibroblasts in the cerebroside sulfate loading test had an attenuated rate of sulfatide hydrolysis. A re-examination of the cerebroside sulfatase reaction revealed that while only limited hydrolysis occurred with low concentrations of taurodeoxycholate or cholate (type I activation), significant hydrolysis of the natural substrate did take place with high concentrations of cholate (type II activation). This suggests that there is a partial cerebroside sulfatase defect in this atypical form of metachromatic leukodystrophy.     

Multiplicity of allergens in peanuts

Crude peanut protein fractions from raw and roasted peanuts were examined in the RAST with 10 sera from patients showing clinical peanut sensitivity. The radioactive uptake results, which were generally high, did not reveal any distinguishable pattern. Two commercially available peanut proteins, peanut lectin and phospholipase D, gave poor RAST responses. Three purified peanut proteins, α-arachin, conarachin I, and concanavalin A-reactive glycoprotein, all gave significant RAST results that were generally lower than those obtained with the crude extracts. The extent of RAST inhibition obtained with these materials was inversely related to their abundance in the total peanut protein. Crossed immunoelectrophoresis with extracts from raw and roasted peanut indicated the presence of 22 and 10 anodically migrating antigens, respectively. Sixteen IgE binding antigens were revealed for raw peanut and seven for roasted peanut after incubation with a mixed serum from the 10 patients in crossed radioimmunoelectrophoresis (CRIE) using ¹²⁵I-labeled anti-IgE. CRIE plates treated with individual serum samples showed that all the patients had specific IgE for the major antigen peak, which has been tentatively identified as α-arachin. This major storage protein of peanut, which is known to be particularly heat resistant, may be of greater clinical significance than its apparently low RAST activity would seem to indicate.     

Postnatal Iron Supplementation with Ferrous Sulfate vs. Ferrous Bis-Glycinate Chelate: Effects on Iron Metabolism,Growth, and Central Nervous System Development in Sprague Dawley Rat Pups

Iron-fortified formulas and iron drops (both usually ferrous sulfate, FS) prevent early life iron deficiency, but may delay growth and adversely affect neurodevelopment by providing excess iron. We used a rat pup model to investigate iron status, growth, and development outcomes following daily iron supplementation (10 mg iron/kg body weight, representative of iron-fortified formula levels) with FS or an alternative, bioavailable form of iron, ferrous bis-glycinate chelate (FC). On postnatal day (PD) 2, sex-matched rat litters (n = 3 litters, 10 pups each) were randomly assigned to receive FS, FC, or vehicle control until PD 14. On PD 15, we evaluated systemic iron regulation and CNS mineral interactions and we interrogated iron loading outcomes in the hippocampus, in search of mechanisms by which iron may influence neurodevelopment. Body iron stores were elevated substantially in iron-supplemented pups. All pups gained weight normally, but brain size on PD 15 was dependent on iron source. This may have been associated with reduced hippocampal oxidative stress but was not associated with CNS mineral interactions, iron regulation, or myelination, as these were unchanged with iron supplementation. Additional studies are warranted to investigate iron form effects on neurodevelopment so that iron recommendations can be optimized for all infants.