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PubMed2001

Interactions of chlorpromazine with milk proteins.

The mode and nature of the binding of chlorpromazine (CPZ), a psychotropic drug, with milk proteins--alpha-lactalbumin (with substantial amounts of alpha-helix, beta-sheet and random coil), alpha-lactoglobulin (a major beta-sheeted protein) and alphas-casein (a random coiled protein) have been studied spectrofluorometrically and spectropolarimetrically. The binding affinity of CPZ for unfolded proteins is comparatively less than that of folded proteins although the number of binding sites is smaller in the latter case, due to the greater extent of binding of CPZ for folded proteins. Thermodynamic analysis reveals that CPZ binds to alpha-lactalbumin and alphas-casein in an endothermic (deltaH degrees is positive) and hydrophobic manner but with beta-lactoglobulin in an exothermic (deltaH degrees is negative) manner. Far UV Circular dichroic studies reveal that CPZ increases the secondary structure of the major beta-sheeted protein, beta-lactoglobulin possibly by increasing the relative contact orders (non-local contacts) within the residues. On the other hand, for proteins possessing random coil, it increases the unfolded state of the protein. CPZ does not affect local contacts in alpha-helix when its interaction is compared with a major alpha-helical protein, myoglobin.

Antipsychotic Agents↗
PubMed2000

Human milk polyunsaturated long-chain fatty acids and secretory immunoglobulin A antibodies and early childhood allergy.

The possible protective effect of breast milk against atopic manifestations in infancy, i.e. atopic eczema and food allergy, has been controversial for the last decades. Besides the methodological problems, differences in the composition of human milk could explain these controversies. The aim of this study was to investigate the composition of polyunsaturated fatty acids (PUFA) and secretory immunoglobulin A (S-IgA) levels to food proteins (ovalbumin and beta-lactoglobulin) and an inhalant allergen (cat) in milk from mothers of allergic and non-allergic children. Blood samples were obtained at birth and at 3 months from 120 children. Skin prick tests were performed at 6, 12 and 18 months, and the development of atopic diseases was assessed in the children. Breast milk samples were collected from their mothers at birth and monthly during the lactation period. Milk PUFA composition was measured by gas chromatography, and enzyme-linked immunosorbent assay (ELISA) was used to measure total S-IgA, anti-cat S-IgA, anti-ovalbumin S-IgA, and anti-beta-lactoglobulin S-IgA. Allergic disease developed in 44/120 children (22/63 children of allergic mothers and 22/57 children of non-allergic mothers). Lower levels of eicosapentaenoic acid, C20:5 n-3 (EPA), docosapentaenoic acid C22:5 n-3 (DPA), and docosatetraenoic acid C22:4 n-6 (DHA) (p < 0.05 for all) were found in mature milk from mothers of allergic as compared to milk from mothers of non-allergic children. The total n-6:total n-3 and the arachidonic acid, C20:4 n-6 (AA):EPA ratios were significantly lower in transitional and mature milk from mothers of allergic children, as compared to milk from mothers of non-allergic children. The PUFA levels in serum of allergic and non-allergic children were largely similar, except for higher levels of C22:4 n-6 and C22:5 n-6 (p < 0.05 for both) and a higher AA:EPA ratio in serum phospholipids in the former group (p < 0.05). Changes in the levels of milk PUFA were reflected in changes in PUFA serum phospholipids, particularly for the n-6 PUFA. The AA: EPA ratio in maternal milk was related, however, to the AA:EPA only in serum from non-allergic children, while this was not the case in allergic children. The levels of total S-IgA, anti-cat S-IgA, anti-ovalbumin S-IgA, and anti-beta-lactoglobulin S-IgA in milk from mothers of allergic, as compared to non-allergic, children were similar through the first 3 months of lactation. Low levels of n-3 PUFA in human milk, and particularly a high AA:EPA ratio in maternal milk and serum phospholipids in the infants, were related to the development of symptoms of allergic disease at 18 months of age. The milk PUFA composition influenced the composition of PUFA in serum phospholipids of the children. We also showed that the lower levels of colostral anti-ovalbumin S-IgA and lower total S-IgA in mature milk from atopic mothers did not influence the development of allergic disease in the children up to 18 months of age. The findings indicate that low alpha-linolenic acid, C18:3 n-3 (LNA) and n-3 long-chain polyunsaturated fatty acids (LCP) 20-22 carbon chains, but not the levels of S-IgA antibodies to allergens, are related to the development of atopy in children.

Animals↗
PubMed1998

Humoral immune and clinical responses to food antigens following acute diarrhoea in children.

OBJECTIVE: To investigate the effect of acute watery diarrhoea in children upon humoral immune responses to food antigens and the subsequent development of food allergy. METHODOLOGY: Serum antibodies to cows' milk, beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin and ovalbumin were measured in 30 children with acute diarrhoea in the acute phase and 1 month after recovery. The children were followed for 1 year to assess the development of food allergy. RESULTS: IgG antibeta-lactoglobulin titres for the study group increased 1 month after recovery compared to the titres during the acute phase (P = 0.02). Antibody concentration for the other antigens studied did not rise. Four children developed positive IgE antibodies to one or more of the allergens after the diarrhoeal episode, although the titres were very low. None showed evidence of allergy to cows' milk or egg during the year-long follow-up. CONCLUSIONS: Acute diarrhoea in children resulted in increased production of IgG antibody to beta-lactoglobulin and had a priming effect for development of positive IgE antibody to cows' milk. Clinical food allergy was not observed in any of the children during the year-long follow-up.

Animals↗
PubMed2004

Monte Carlo simulations of flexible polyanions complexing with whey proteins at their isoelectric point.

Electrostatic complexation of flexible polyanions with the whey proteins alpha-lactalbumin and beta-lactoglobulin is studied using Monte Carlo simulations. The proteins are considered at their respective isoelectric points. Discrete charges on the model polyelectrolytes and proteins interact through Debye-Huckel potentials. Protein excluded volume is taken into account through a coarse-grained model of the protein shape. Consistent with experimental results, it is found that alpha-lactalbumin complexes much more strongly than beta-lactoglobulin. For alpha-lactalbumin, strong complexation is due to localized binding to a single large positive "charge patch," whereas for beta-lactoglobulin, weak complexation is due to diffuse binding to multiple smaller charge patches.

Anions↗
PubMed1984

Reduction in the antigenicity of whey proteins by heat treatment: a possible strategy for producing a hypoallergenic infant milk formula.

Residual antigenic protein in heat-denatured cow's milk whey and in two commercial infant milk formulas was determined using enzyme-linked immunosorbent assays specific for beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, bovine IgG1 and alpha-casein. This immunochemical assessment of antigenicity was related to the capacity of the preparations to sensitize immunologically when fed to guinea-pigs for 2 weeks. Antibody production was measured and the susceptibility of the animals to systemic anaphylaxis was assessed by injecting them intravenously with heated or unheated milk proteins. Whey protein that had been heated at 100 degrees or 115 degrees for 30 min was extensively denatured and, in contrast to pasteurized whey, failed to sensitize guinea-pigs for anaphylaxis. Antibody production was undetected or very low. The proteins in SMA powder and SMA Gold Cap liquid concentrate were less denatured and animals given these formulas prepared according to the maker's instructions produced relatively high levels of antibodies to beta-lactoglobulin and alpha-casein and a majority developed anaphylaxis when injected intravenously with these products. As well as failing to sensitize, whey that had received severe heat treatment did not, in most cases, elicit anaphylaxis when injected into animals that had been sensitized with unheated milk. Discrimination between antibodies of the IgG1 and IgG2 subclasses specific for beta-lactoglobulin showed that IgG1, the principal anaphylactic antibody in guinea-pigs, was preferentially depressed in animals drinking heat-denatured milk preparations. The results suggest that heat denaturation of whey protein may be a logical and simple strategy for producing a hypoallergenic baby milk. Nevertheless, the value of experiments in guinea-pigs for predicting results in man is uncertain and the proposal awaits assessment in clinical trials.

Anaphylaxis↗
PubMedDate not supplied

Mast cell degranulation alters lymphatic contractile activity through action of histamine.

OBJECTIVE: Mast cells reside in most tissues and in close association with blood vessels and nerves, areas where lymphatic vessels are also present. Mast cells and lymphatic vessels are two important players in the development of the inflammatory process. This study was designed to examine the effects of mast cell degranulation on the contractile activity of mesenteric lymphatic vessels. METHODS: Lymphatic vessel contractile activity was assessed in vitro by video microscopy of the mesentery of cow's milk-sensitized guinea pigs upon application of beta-lactoglobulin and compared to the response measured in sham animals. RESULTS: Application of 5-10 microM beta-lactoglobulin increased lymphatic vessel constriction frequency and decreased constriction amplitude (n = 12). This effect was not seen in sham-treated animals (n = 16) and was not due to an increased number of mast cells in the mesentery of the milk-sensitized animals, as revealed by histological examination. Two known mast cell-derived mediators, histamine and thromboxane A2, via stable mimetic U46619 also altered lymphatic pumping in a similar manner, but only pretreatment with the histamine H1 receptor antagonist pyrilamine (1 microM) could reduce the beta-lactoglobulin-induced response. The thromboxane A2 receptor antagonist, SQ 29548, and the 5-lipoxygenase inhibitor, caffeic acid, were without significant effect. CONCLUSION: In the in vitro mesenteric preparation, mast cell degranulation altered lymphatic contractile activity via the release of a mediator suggested to be histamine and the subsequent activation of H1 receptors. This action could potentially interfere with the expected ability of lymphatic vessels to reduce edema during inflammation.

Animals↗
PubMed1996

Antiviral effects of milk proteins: acylation results in polyanionic compounds with potent activity against human immunodeficiency virus types 1 and 2 in vitro.

A number of native and modified milk proteins from bovine or human sources were analyzed for their inhibitory effects on human immunodeficiency virus type 1 (HIV-1) and HIV-2 in vitro in an MT4 cell test system. The proteins investigated were lactoferrin, alpha-lactalbumin, beta-lactoglobulin A, and beta-lactoglobulin B. By acylation of the amino function of the lysine residues in the proteins, using anhydrides of succinic acid or cis-aconitic acid, protein derivatives were obtained that all showed a strong antiviral activity against human immunodeficiency virus type 1 and/or 2. The in vitro IC50 values of the aconitylated proteins were in the concentration range of 0.3 to 3 nM. Succinylation or aconitylation of alpha-lactalbumin and beta-lactoglobulin A/B also produced strong anti-HIV-2 activity with IC50 values on the order 500 to 3000 nM. All compounds showed virtually no cytotoxicity at the concentration used. Peptide-scanning studies indicated that the native lactoferrin as well as the charged modified proteins strongly bind to the V3 loop of the gp120 envelope protein, with Kd values in the same concentration range as the above-mentioned IC50. Therefore, shielding of this domain, resulting in inhibition of virus-cell fusion and entry of the virus into MT4 cells, may be the likely underlying mechanism of antiviral action.

Aconitic Acid↗
PubMed1994

Mapping and analysis of dairy cattle quantitative trait loci by maximum likelihood methodology using milk protein genes as genetic markers.

Maximum likelihood methodology was used to estimate effects of both a marker gene and a linked quantitative trait locus (QTL) on quantitative traits in a segregating population. Two alleles were assumed for the QTL. In addition to the effects of genotypes at both loci on the mean of the quantitative trait, recombination frequency between the loci, frequency of the QTL alleles and the residual standard deviation were also estimated. Thus six parameters were estimated in addition to the marker genotype means. The statistical model was tested on simulated data, and used to estimate direct and linked effects of the milk protein genes, beta-lactoglobulin, kappa-casein, and beta-casein, on milk, fat, and protein production and fat and protein percent in the Dutch dairy cattle population. beta-Lactoglobulin had significant direct effects on milk yield and fat percent. kappa-Casein had significant direct effects on milk yield, protein percent and fat yield. beta-Casein had significant direct effects on milk yield, fat and protein percent and fat and protein yield. Linked QTL with significant effects on fat percent were found for kappa-casein and beta-casein. Since the beta-casein and kappa-casein genes are closely linked, it is likely that the same QTL was detected for those two markers. Further, a QTL with a significant effect on fat yield was found to be linked to kappa-casein and a QTL with a significant effect on protein yield was linked to beta-lactoglobulin.

Alleles↗
PubMed1989

Serum antibodies to cow's milk proteins in pediatric inflammatory bowel disease. Crohn's disease versus ulcerative colitis.

Serum antibodies to five cow's milk proteins (alpha-casein, bovine serum albumin, beta-lactoglobulin A and B, and alpha-lactalbumin) were investigated in young patients with inflammatory bowel disease (56 Crohn's disease, 24 ulcerative colitis). IgG antibodies against bovine serum albumin, beta-lactoglobulin A and beta-lactoglobulin B were higher in Crohn's disease patients than in those with ulcerative colitis or the controls. IgG anti-bovine serum albumin antibodies were higher in those Crohn's disease patients who had higher scores of disease activity. Finally, IgA antibodies to alpha-casein were higher in patients with Crohn's disease and ulcerative colitis when compared to controls. These findings may be due to increased uptake of dietary antigens or enhanced immunological response occurring in Crohn's disease patients.

Adolescent↗
PubMed1982

Milk antigen absorption in the preterm and term neonate.

The concentrations of beta-lactoglobulin was measured in the sera of 47 preterm an term neonates during the first few days of life under standardised conditions after feeding with a cows' milk'based formula. Preterm neonates, particularly those of less than 33 weeks' gestation, had higher serum concentrations of beta-lactoglobulin than term neonates given an equivalent mild feed. Prior feeding with breast milk did not diminish the amount of beta-lactoglobulin absorbed. Our results suggest tha te ability of the gastrointestinal tract to exclude antigenically intact food proteins increases with gestational age and that gut closure occurs normally before birth in man.

Breast Feeding↗
PubMed2002

Humoral and cell mediated immune response to cow's milk proteins in Behçet's disease.

OBJECTIVE: To investigate the humoral and cellular immune response against cow's milk proteins in Behçet's disease and to distinguish any behaviour during active or inactive disease. METHODS: Peripheral blood mononuclear cells from 16 patients and from eight normal controls were cultured in the presence of phytohaemagglutinin (PHA), beta-casein, beta-lactoglobulin, or chicken egg albumin. Interferon gamma (IFNgamma) and interleukin 4 (IL4) were measured in the culture supernatants by enzyme linked immunosorbent assay (ELISA). Serum samples from 46 patients with Behçet's disease and from 37 healthy subjects were also studied for antibody detection. Antibodies to beta-casein, beta-lactoglobulin, and chicken egg albumin were determined by ELISA. RESULTS: High IFNgamma but not IL4 levels were found in the supernatants of lymphocytes from patients with active disease cultured in the presence of cow's milk proteins. Levels were comparable with those obtained in cultures stimulated with PHA. A significantly higher level of anti-beta-casein and anti-beta-lactoglobulin IgG and IgA antibodies was found in patients with active Behçet's disease. No relation was found between their occurrence and the age of the patients, the duration of disease, or the presence of gastrointestinal abnormalities. Antibodies to chicken albumin were detected at low levels and with a prevalence similar to that of healthy subjects. CONCLUSION: The results indicate that an active immune response occurs in Behçet's disease. This response involves an increased frequency of antibodies to cow's milk protein and a strong Th1 polarisation after exposure to these antigens. The occurrence of these abnormalities supports a putative role for cow's milk proteins immune response in the pathogenesis of Behçet's disease.

Acute Disease↗
PubMed1987

Passage of dietary antigens into the blood of children with coeliac disease. Quantification and size distribution of absorbed antigens.

The uptake of ovalbumin (OA) from egg and beta-lactoglobulin (BLG) from cow's milk into the blood was investigated for seven hours after a test meal in five children with coeliac disease on a gluten free diet and after gluten challenge, and in five children with normal jejunal mucosa. Ovalbumin was detectable by ELISA in three of five coeliac children (maximal concentrations 8-178 ng/ml serum) and in five of five controls (maximal 4-91 ng/ml serum). Beta-lactoglobulin was detected in three of five coeliac children (maximal 0.6-6 ng/ml serum) and in two of five controls (maximal 0.5 and 50 ng/ml serum). No clear relationship was seen between maximal antigen concentrations and titres of serum IgG or IgA antibodies determined by ELISA, or as percentage antigen binding in a Farr type radioimmunoassay. Ovalbumin and beta-lactoglobulin was seen in serum of all coeliac patients and controls by HPLC fractionation in combination with ELISA, either in high MW fractions, or at the Mr of native OA and BLG, respectively. In one control degradation products (about 17 kD) of BLG were detectable in serum. The serum concentrations of OA and BLG were increased on gluten challenge in four or five coeliac children, indicating increased macromolecular passage through the gut mucosa in untreated coeliac disease.

Antibodies↗
PubMedDate not supplied

Measurements of the wettability of protein-covered hydroxyapatite surfaces.

We developed a new method (dropping time method, DTM) to investigate the wettability of a surface of a protein layer adsorbed on glass plates in aqueous solution. However, the previous setup of DTM can only be utilized for optically transparent materials. In this study, we have extended the method to optically nontransparent materials such as hydroxyapatite plates. DTM is based on measuring the dropping time of a liquid film along a protein-covered surface when this surface is instantaneously vertically removed from the protein solution. The intensity of the reflected light beam depends on the presence of a liquid film on the surface. This allows to estimate the movement of the liquid film along the sorbent surface. Thus, the extended DTM can be used for determining the wettability of optically nontransparent solid plates. The adsorption behavior of four proteins (albumin, lysozyme, beta-lactoglobulin, ovalbumin) on a hydrophobic hydroxyapatite plate in water was studied by this method. When adsorbed from a protein solution of high concentration, the surfaces of adsorbed proteins, except ovalbumin, were fairly hydrophilic; this hydrophilicity was already attained at the initial stage of the adsorption process. The surface of ovalbumin on hydroxyapatite was more hydrophobic than those of the other proteins, and the hydrophilicity increased with the protein adsorption process. At low protein concentration, the hydrophilicity increased in the course of the adsorption process. The change in hydrophilicity with time depends on the kind of protein. Hen's egg lysozyme is more hydrophilic and the time to reach saturation is shorter than for the other proteins. The processes of increasing hydrophilicity of the surface of human serum albumin, beta-lactoglobulin and ovalbumin are similar. However, for beta-lactoglobulin hydrophobicity at adsorption saturation is stronger than for human serum albumin and ovalbumin. Thus, using DTM it is shown that the hydrophilicity of the surface of adsorbed protein on hydroxyapatite depends strongly on the kind of protein.

Adsorption↗
PubMed1997

Circulating antibodies to common food antigens in Japanese children with IDDM.

OBJECTIVE: To investigate the humoral immune response to common food antigens in Japanese children with IDDM. RESEARCH DESIGN AND METHODS: IgG antibodies to cow's milk, beta-lactoglobulin, bovine serum albumin (BSA), alpha-lactalbumin, and hens egg ovalbumin were examined by enzyme-linked immunosorbent assay in the sera of 33 patients with IDDM, ages 11.8 +/- 3.4 years. The data were compared with that of 50 normal subjects, ages 10.3 +/- 5.1 years, who acted as control subjects. A positive antibody to a food antigen was defined as an antibody titer greater than the 95th percentile value in normal subjects. RESULTS: Children with IDDM had significantly higher median titers of IgG antibodies to beta-lactoglobulin and ovalbumin (P = 0.03 and P = 0.0005 respectively). More children with IDDM than control subjects had positive IgG antibody to ovalbumin (21 vs. 6%, P = 0.04). Titers, as well as the number of positive antibodies to other food antigens, including BSA, did not differ between the two groups. CONCLUSIONS: Japanese children with IDDM show an enhanced humoral immune response to beta-lactoglobulin and ovalbumin, a phenomenon that may be related to the pathogenesis of the disease.

Adolescent↗
PubMed2006

Modeling of lactose crystallization and color changes in model infant foods.

Lactose crystallization and color changes in formulas containing beta-lactoglobulin and gelatinized starch were investigated. Model infant formulas were prepared by colyophilization of 3 components (lactose, beta-lactoglobulin, and gelatinized starch). A mixture design was used to choose the percentage of each mixture component. These formulas were stored for 3 mo at different relative humidities (RH), ranging from approximately 0 to 94.6%, to study the lactose crystallization and color changes. Crystallization kinetics was studied by gravimetric methods, and lactose state (crystalline vs. amorphous) was verified before and after storage by differential scanning calorimetry. Before storage, lyophilized lactose was amorphous, but during storage it crystallized, depending on the RH. The lactose crystallization RH depended on the quantity of beta-lactoglobulin and gelatinized starch, and by increasing these quantities, the crystallization RH increased. For some formulas, the crystallization RH was noted at 3 different RH during storage. The first was noted after 1 d of storage and the second and third were observed later on, showing that crystallization is a time-dependent phenomenon. Nonenzymatic browning was studied in model infant formulas by yellow color changes of samples at 11.3, 43.2, 54.5, and 75.4% RH. In this study, 7 mathematical models were proposed to predict the moisture sorption properties and color changes at different RH, and the models were validated by experimental results.

Adsorption↗
PubMed1975

Examination of cottage cheese whey proteins by scanning electron microscopy: relationship to membrane fouling during ultrafiltration.

Deposits formed on the membrane during ultrafiltration of aqueous solutions of individual whey proteins were examined under a scanning electron microscope. Gamma-globulin formed granules which agglomerated and stacked into layers to form a porous matrix on the membrane. Beta-lactoglobulin and bovine serum albumin both formed sheets on the membrane and formed multimers which were identified by sodium dodecyl sulfate gel electrophoresis. Beta-lactoglobulin also formed strands where deposits were not thick. Alpha-lactalbumin formed smooth spherical particles which did not hinder water permeation greatly. Studies of ultrafiltration rate indicated that beta-lactoglobulin and gamma-globulin were most significant in causing permeation flux decline by surface fouling.

Animals↗
PubMed1976

Response to labeled precursor amino acids, varying cell density, and graded amino acid complement for protein synthesis in mammary cell culture.

Effect of labeled precursor amino acids, varying cell densities, graded quantities of amino acid complement, and incubation environment on milk protein synthesis were studied with cultures of mammary cells isolated from Sprague Dawley rats. The essential amino acid complement of Eagle's minimal essential medium was used as base. Protein synthesis, measured by incorporation of labeled lysine, leucine, and phenylalanine, was affected by source of label for the "beta-lactoglobulin fraction" and beta-casein but not alpha-lactalbumin. Cell numbers between 6 X 106 and 6 X 107 per 5 ml of culture medium did not significantly alter rates of synthesis. Increasing amounts of amino acid concentration from one to three-fold increased synthesis of "beta-lactoglobulin fraction" and alpha-lactalbumin regardless of cell population. Response to addition of essential amino acid for "beta-lactoglobulin fraction" synthesis was linear over one to five-fold with 30.9 mug/flask per fold addition (linear regression coefficient; squared correlation = .91). Results were similar for beta-casein synthesis; 25.9 mug/flask and squared correlation = .91. No culturing effects between carbon dioxide and conventional incubators were significant.

Amino Acids, Essential↗
PubMed1978

Limiting amino acids for milk protein synthesis by bovine mammary cells in culture.

Experiments are presented to determine the effect of labeled precursor amino acid on synthesis of beta-lactoglobulin and beta-casein and to identify the most limiting amino acids in Eagle's minimal essential medium for synthesis of milk protein. Protein synthesis was measured by incorporation of carbon-14 labeled amino acids into milk protein from bovine mammary cell culture. Mammary tissue from 13 Holsteins (12.7 kg milk/day) was dispersed and cultured for 18 h. In Experiment 1, three replications (cows) with three amino acid mixtures, utilizing labeled lysine or leucine as the marker amino acid, showed that labeled lysine overestimated the effect of medium lysine, and labeled leucine overstimated the effect of leucine on beta-lactoglobulin and beta-casein synthesis. Subsequently Experiment 2 utilized 10 replications (cows) to determine the effect of a three-fold increase of each of 13 amino acids in Eagle's medium. Increased threonine or methionine improved beta-lactoglobulin synthesis and cystine increased beta-casein. Second and third best response in beta-casein were from addition of methionine and threonine. Combined analysis from 10 cows and two protein responses by multivariate procedures identified, in order of decreasing magnitude, cystine, threonine, and methionine as limiting amino acids in the dispersed cell culture.

Amino Acids↗