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At least 811 records · Page 45Linked to original sources
PubMed1989

Antibacterial prophylaxis with lactoferrin in neutropenic patients.

The prevention of enterogenic infection by human lactoferrin was tested in five neutropenic patients receiving chemotherapy for acute myelogenous leukemia. Lactoferrin did not significantly delay the onset of infection but reduced its duration and severity as judged from the course of fever. Compared with nine matched controls, lactoferrin-treated patients had a lower incidence of bacteremia on the whole and of gram-negative bacteremia in particular.

Adolescent↗
PubMed1984

Effect of lactoferrin on the growth of a human colon adenocarcinoma cell line--comparison with transferrin.

Lactoferrin was examined for its effect on the growth of a human colon adenocarcinoma cell line (HT 29) in culture and its action was compared to that produced by transferrin and two different iron solutions (ferrous sulfate and ferric chloride). When transferrin was replaced by either iron solutions the cell grew in proportion to the quantity added and the maximal effect obtained was identical to that produced by transferrin alone. When transferrin was replaced by lactoferrin the cells were unable to proliferate for a long time. However, in the presence of low-concentration iron solutions, lactoferrin stimulated the cell growth, and the effect was more pronounced with the ferric chloride solution.

Adenocarcinoma↗
PubMed1999

Elevated CSF lactoferrin in superficial siderosis of the central nervous system.

This study sought to identify abnormalities in the levels of iron transport proteins in patients with superficial siderosis of the central nervous system. We compared patients with superficial siderosis (n = 7) with patients suffering from various other neurological disorders (n = 176, total). CSF and serum levels of lactoferrin, and CSF levels of transferrin were measured by enzyme-linked immunosorbent assay. Serum transferrin was measured by nephelometry. Lactoferrin, but not transferrin, levels in the CSF were significantly elevated in superficial siderosis. Unexpectedly, CSF transferrin was decreased in multiple sclerosis patients. Enhanced CSF lactoferrin may reflect an increased iron transport requirement in the central nervous system in superficial siderosis and might be a useful measure for monitoring response to therapy.

Central Nervous System Diseases↗
PubMed2001

Treatment of enterogenic endotoxinemia with lactoferrin in rats.

Enterogenic endotoxinemia was induced in 28 Wistar rats by means of intraperitoneal injection of 80 mg/kg carrageenan and intraduodenal administration of 5 x 10(10)/kg Escherichia coli bacteria and 10 mg/kg nebacetin. The control group A received 600 mg/kg albumin in addition via the duodenal probe, and the groups B, C and D received 20, 40 and 80 mg/kg lactoferrin, respectively. The therapeutic effect was investigated by determining the endotoxin activity in the plasma every hour. In addition, the bacterial contamination of peritoneal lavages and mesenteric lymph nodes was checked by incubation for 48 h at 37 degrees C. The period of observation was 5 h. There was a dose-dependent improvement of the endotoxin activity in plasma and the bacterial contamination of the peritoneum cavity and mesenteric lymph nodes after lactoferrin administration. The maximum plasma endotoxin activity could be reduced by 89% with 80 mg/kg lactoferrin.

Albumins↗
PubMed1985

Correlations between human salivary levels of lysozyme, lactoferrin, salivary peroxidase and secretory immunoglobulin A with different stimulatory states and over time.

Within-subject correlations for the levels of these salivary proteins were determined in unstimulated and stimulated parotid saliva collected from 8 subjects and for stimulated parotid saliva collected from the same subjects once a week for a 4-week period. Initial correlations between unstimulated and stimulated samples were high and statistically significant (p less than 0.05) for all four proteins. When data were adjusted for variation attributable to flow rate and total protein, some correlations remained the same and those for lysozyme, lactoferrin and salivary peroxidase increased. However, the correlation for secretory immunoglobulin A decreased to a point where it was no longer statistically significant. In the weekly comparison, within-subject correlations across weeks were significant (p less than or equal to 0.05) for lysozyme, lactoferrin and salivary peroxidase, but not for immunoglobulin A. After adjustment for flow rate and total protein, the pattern of correlation was unchanged. Thus the relative rankings of subjects for levels of lysozyme, lactoferrin or salivary peroxidase may be consistent across stimulatory states, even though absolute concentrations may change; levels of these proteins in stimulated parotid saliva may be maintained over time. Secretory immunoglobulin A appears to be more subject to short-term variation.

Adult↗
PubMed1990

Evidence for a different mechanism of lactoferrin and transferrin translocation on HT 29-D4 cells.

The fate of [125I] lactoferrin after binding on its specific receptor on HT29-D4 cells, a clone of HT29 cells, was studied and compared with that of [125I]transferrin. Time courses of protein binding in relation with temperature clearly show that different mechanisms of ligand-transportation for the two glycoproteins exist on these cells: whereas transferrin would enter into the cell probably by a relatively classic pathway of receptor-mediated endocytosis, lactoferrin and its specific receptor would not be internalized. Thus the mechanism by which lactoferrin promotes HT29 cell growth seems quite different from that of transferrin on the same cells.

Biological Transport↗
PubMed1992

Structural organization of the mouse lactoferrin gene.

The complete structure of the mouse lactoferrin gene is presented. Mouse lactoferrin (mLF) is encoded by a single copy gene of approximately 30 kilobases (kb) in size. The gene is organized into 17 exons separated by 16 introns. The exons range in size from 48 base pairs (bp) to 190 bp whereas the introns range from 0.2 kb to 4.3 kb. Structural analysis of the mouse lactoferrin gene reveals that this gene shares a similar intron-exon distribution pattern with both human transferrin and chicken ovotransferrin.

Animals↗
PubMed1982

Plasma lactoferrin levels in pregnancy and cystic fibrosis.

Plasma lactoferrin levels were determined by radioimmunoassay for the different weeks of normal pregnancy, in normal healthy adults and in children with and without cystic fibrosis. The lactoferrin levels were higher in pregnancy than in both male and female normal adults and showed a slight progressive increase up to week 29 and thereafter remained high. Five our of seven children with cystic fibrosis had markedly raised plasma lactoferrin levels from six to 16 times higher than the mean of a control group of children.

Adolescent↗
PubMed1992

Interaction of calmodulin with lactoferrin.

Calmodulin, as a major intracellular calcium-binding protein, regulates many Ca(2+)-dependent enzymes and plays an important role in a wide spectrum of cellular functions of the eukaryotes. Interaction between calmodulin and human lactoferrin, a 78 kDa protein with antibacterial properties, was found in the presence of Ca2+ using (i) a method for the detection of calmodulin binding proteins with biotinylated calmodulin, (ii) affinity chromatography on an agarose-calmodulin column with subsequent detection by an enzyme-linked immunosorbent assay (ELISA). The binding of calmodulin to lactoferrin blocked the ability of lactoferrin to agglutinate Micrococcus lysodeikticus.

Agglutination Tests↗
PubMed1995

Structural determination of two N-linked glycans isolated from recombinant human lactoferrin expressed in BHK cells.

A full-length cDNA coding for human lactoferrin was isolated from a mammary gland library and the recombinant protein was expressed in BHK cells as described by Stowell K. M. et al. [1991, Biochem. J. 276, 349-355]. Two N-linked glycans from purified recombinant lactoferrin were released by hydrazinolysis and analyzed by 400-MHz 1H-NMR spectroscopy. The identified structures corresponded to N-acetyllactosaminic biantennary glycans and were alpha-2,3-disialylated forms (80%) or alpha-2,3-monosialylated (20%) forms. Moreover, 70% of total glycans were alpha-1,6-fucosylated at the GlcNAc residue linked to asparagine. In regard to its glycan moiety, the recombinant glycoprotein is close to native lactoferrins from milk or leucocytes but shows specific structural features which should be taken into account prior to in vivo and in vitro biological studies.

Animals↗
PubMed1985

A monoclonal antibody-based immunoassay for human lactoferrin.

Monoclonal antibodies against human lactoferrin define at least 3 and possibly as many as 6 different epitopes. A sandwich enzyme-linked immunoassay, using monoclonals against different epitopes, has been optimised for the measurement of serum lactoferrin. In 35 samples from healthy adults the mean lactoferrin content of serum from blood clotted overnight was 0.54 +/- 0.26 micrograms/ml.

Adult↗
PubMed1989

Preliminary crystallographic studies on human apo-lactoferrin in its native and deglycosylated forms.

Human apo-lactoferrin in both native and deglycosylated forms has been purified, and crystals obtained by dialysis against low ionic strength buffer solutions. The crystals of native apo-lactoferrin are orthorhombic, space group P2(1)2(1)2(1) with cell dimensions a = 222.0 A, b = 115.6 A, c = 77.8 A and have two protein molecules per asymmetric unit. Two crystal forms of deglycosylated apo-lactoferrin have been obtained. One is orthorhombic, space group P2(1)2(1)2(1), with cell dimensions a = 152.1 A, b = 94.6 A, c = 55.8 A. The second is tetragonal, space group I4, with cell dimensions a = b = 189.4 A, c = 55.1 A. Both of the latter have only one molecule per asymmetric unit, and are suitable for high-resolution X-ray structure analysis.

Apoproteins↗
PubMed1981

Immunological identification of lactoferrin as a shared antigen on radioiodinated human sperm surface and in radioiodinated human seminal plasma.

After lactoperoxidase-catalyzed iodination of either human sperm surface or human seminal plasma, a 72-76 kdalton component was resolved on SDS-7.5% polyacrylamide gels. The approximate molecular weight of this component was consistent with that of human lactoferrin, a major sperm-coating antigen. Immunoprecipitation of labeled sperm surface and of labeled seminal plasma with specific anti-human lactoferrin antibody identified lactoferrin as a constituent of this 72-76 kdalton component both on human sperm surface and in human seminal plasma. These data show that components which have been inferred to be shared because of similarities in biochemical characteristics also contain immunologically identical components.

Absorption↗
PubMed1992

Nucleotide and primary amino acid sequence of porcine lactoferrin.

A cDNA encoding porcine lactoferrin (pLF) was isolated from a porcine mammary gland lambda gt11 cDNA library using human lactoferrin cDNA as the hybridization probe. Nucleotide sequence analysis indicates that pLF is 686 amino acids in length and shares 72.6%, 70.7% and 62.2% overall amino acid sequence identity with bovine, human and murine lactoferrin, respectively.

Amino Acid Sequence↗
PubMed1990

Ferritin-dependent lipid peroxidation by stimulated neutrophils: inhibition by myeloperoxidase-derived hypochlorous acid but not by endogenous lactoferrin.

Human neutrophils stimulated with phorbol myristate acetate or formylmethionylleucylphenylalanine caused superoxide-dependent release of iron from feritin, measured as the formation of a ferrous-ferrozine complex. The stimulated cells also caused ferritin-dependent peroxidation of phospholipid liposomes. Peroxidation was inhibited by lactoferrin, but only at concentrations considerably in excess of what could be achieved by release of endogenous lactoferrin. Peroxidation was enhanced by catalase and methionine, especially when stimulants that release myeloperoxidase were used. Peroxidation was inhibited by added myeloperoxidase. These results are explained by myeloperoxidase catalysing the formation of hypochlorous acid (HOCl) and the HOCl reacting with the lipid to inhibit peroxidation. Thus, neutrophils are able to use ferritin to promote lipid peroxidation. This may be limited under some conditions by iron binding to lactoferrin or transferrin, and more generally by reactions of the lipid with myeloperoxidase-derived HOCl. However, the latter reactions themselves may be harmful.

Ferritins↗
PubMed1996

Comparative study of lactoferrin and other blood markers of inflammatory stress between preeclamptic and normal pregnancies.

OBJECTIVE: To test lactoferrin as a blood discriminator of neutrophil activation between normal and preeclamptic pregnancy. DESIGN: Comparative study between normal (n = 40) and preeclamptic women receiving treatment (n = 42) in the third trimester of pregnancy and in the post partum period (30 women with normal pregnancy and 22 with preeclampsia). METHODS: Blood, serum or plasma measurements of neutrophils, lactoferrin, vitamin C, vitamin E, lipid peroxidation products, elastase, C-reactive protein (CRP), gamma-glutamyltranspeptidase (gamma GT), haptoglobin, osmotic fragility, urea, creatinine, uric acid, transaminases (ASAT, ALAT), lactic dehydrogenase (LDH), platelets, red and white blood cells. RESULTS: In preeclamptic women the ratios of lactoferrin per neutrophil or per erythrocyte are higher before delivery than in normal women but decrease after delivery. Delivery induces a greater inflammatory response in normal pregnancy as detected by blood concentrations of inflammatory markers and hepatic and renal parameters. CONCLUSION: Whereas in normal pregnant women neutrophil activation increases with delivery, in preeclamptic women the opposite occurs.

Adult↗
PubMed1976

Failure of rabbit reticulocytes to incorporate conalbumin or lactoferrin iron.

Despite the remarkable molecular similarity of human lactoferrin and human transferrin, the results of this investigation indicate that human lactoferrin was unable to furnish rabbit reticulocytes with iron for heme synthesis. Although conalbumin closely resembles transferrin in many of its properties, conalbumin iron-binding differs from human transferrin iron-binding. There are conflicting reports in the literature regarding conalbumin's ability to furnish iron to reticulocytes. In this study, small amounts of lactoferrin or conalbumin were adsorbed to mature and immature cell surfaces but neither of these iron-binding proteins surrendered iron intracellularly to reticulocytes for heme synthesis.

Animals↗
PubMed1982

Enhanced production of hydroxyl radicals by the xanthine-xanthine oxidase reaction in the presence of lactoferrin.

The generation of hydroxyl radicals by the xanthine-xanthine oxidase reaction (C. Beauchamp and I. Fridovich (1970) J. Biol. Chem. 245, 4641-1616) has been shown to be increased by iron-saturated lactoferrin isolated from pig neutrophils. Hydroxyl radical production, measured by EPR spin trapping and by ethylene production from alpha-keto-gamma-methiol butyric acid, has been demonstrated to be produced by a Fenton-type Haber-Weiss reaction catalysed by lactoferrin. The possibility that lactoferrin catalyses such a reaction in vivo is considered.

Animals↗