Unbound vascular endothelial growth factor and its receptors in breast, human milk, and newborn intestine.
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BACKGROUND: Human milk, rich in cytokines, may contain the potent permeability- and angiogenesis-promoting agent vascular endothelial growth factor (VEGF). OBJECTIVE: We wanted to study whether free or bound VEGF is present in human milk and whether it and its receptors (VEGFR-1 and -2) are expressed in lactating breast or newborn intestinal tissue. DESIGN: The study had a longitudinal design with collection of human milk from healthy (n = 32) and diabetic (n = 5) women at 2, 7, and 30 d postpartum. Milk was analyzed for VEGF by enzyme-linked immunosorbent assay along with plasma samples collected 2 d postpartum. Immunohistochemistry was used to localize VEGF and its receptors in lactating breast and newborn intestine. Gel filtration with radiolabeled VEGF was performed to study whether human milk contains VEGF binding proteins. RESULTS: Human milk VEGF concentrations in healthy (76 +/- 19 microg/L, x +/- SD) and diabetic (75 +/- 25 microg/L) women did not differ at 2, 7 (23 +/- 7 and 27 +/- 8 microg/L, respectively), or 30 d (14 +/- 5 and 17 +/- 7 microg/L, respectively) postpartum. VEGF was undetectable in all but 3 plasma samples. Human milk was free of VEGF binding proteins. VEGFR-1 and -2 immunoreactivity was seen in the glandular epithelial cells of the newborn intestine and lactating breast, whereas VEGF was present only in breast glandular epithelium. CONCLUSIONS: The high concentrations of VEGF in human milk, especially colostrum, are not affected by maternal diabetes and may play a role in newborn nutrition. (+info)
Characterization and tissue distribution of 6-O-beta-D-galactopyranosyl myo-inositol in the rat.
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A disaccharide was isolated from rat mammary tissue and determined to be 6-O-beta-galactopyranosyl myo-inositol (6-beta-galactinol) on the basis of combined gas-liquid chromatography-mass spectrometry of the permethylated and peracetylated derivatives as well as previously reported chemical and enzymatic evidence. 6-beta-Galactinol, also found in rat milk, increased during lactation, and on the 18th day represented approximately 17% of the total non-lipid neutral myo-inositol. The sugar was absent in all other rat tissues examined, suggesting a unique association with the process of lactation. This novel galactoside of one human subject on the basis of paper and gas-liquid chromatography. (+info)
Contamination of expressed human breast milk with an epidemic multiresistant Staphylococcus aureus clone.
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Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major cause of outbreaks in intensive care units. Infants make up a sector of the population that presents a high risk for MRSA infections. Mother-to-infant transmission has been indicated as a possible cause of MRSA infections in neonates. The occurrence and characteristics of MRSA in samples of banked human milk were investigated by selective culture, antibiogram and pulsed-field gel electrophoresis. MRSA contamination was found in 11% of 500 samples of expressed, fresh-frozen milk from 500 different donors at five Brazilian milk banks. The great majority of the contaminated samples passed breast milk quality control criteria for dispensing as raw milk under Brazilian and American guidelines. Most of the MRSA isolates belonged to the Brazilian epidemic clone, which is reported to be widespread in several Brazilian states, in Argentina and in Portugal. It is concluded that expressed breast milk can be a reservoir of multiresistant S. aureus epidemic clones. Studies are necessary to assess the source of contamination and potential role of MRSA-contaminated milk in the transmission of MRSA to neonates. (+info)
Measurement of betacellulin levels in bovine serum, colostrum and milk.
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Betacellulin, a member of the epidermal growth factor (EGF) family, was originally isolated and identified from the conditioned medium from a murine pancreatic beta-cell carcinoma cell line. Recently, we isolated bovine betacellulin from a growth factor enriched cheese whey extract, but there is no information on the presence of betacellulin in other biological fluids. We have cloned the cDNA for bovine betacellulin, produced recombinant betacellulin and shown that it has a similar potency to the purified native molecule in stimulating the proliferation of Balb/c3T3 fibroblasts. We have produced a polyclonal antiserum to bovine betacellulin which did not cross-react with EGF or transforming growth factor-alpha (TGF-alpha). The antibody was used in a homologous RIA that was able to detect betacellulin in pooled bovine colostrum sampled during the first 3 days after calving (2.30+/-0.11 ng/ml mean+/-s.e.m.; n=6), in bovine milk soluble fraction (1.93+/-0.64 ng/ml mean+/-s.e.m.; n=5) and in bovine cheese whey (2.59+/-0.16 ng/ml mean+/-s.e.m.; n=3). The betacellulin concentration in foetal bovine serum (FBS) (3.68+/-0.59 ng/ml mean+/-s.e.m.; n=6) greatly exceeded that of betacellulin in serum from male calves 1 and 5 weeks of age (0.53+/-0.15 ng/ml and 0.70+/- 0.09 ng/ml respectively; mean+/-s.e.m.; n=9). Betacellulin measured in the serum of these same animals when aged between 27 and 43 weeks was below the detection limits of the RIA. Sera from 10 out of 36 unmated heifers contained betacellulin levels within the detection limits of the assay (0.433+/-0.06 ng/ml mean+/-s.e.m.; n=10). The presence of betacellulin in bovine colostrum and milk suggests that it plays a role in the growth and development of the neonate and/or mammary gland function. The results also show that betacellulin is undetectable in the castrated adult male circulation. Additionally, although present in very low amounts, serum betacellulin could be under hormonal regulation in the female, since betacellulin was detected in sera from 27% of the unmated heifers examined in this study. The high levels of betacellulin detected in FBS relative to newborn and adult serum suggests a possible endocrine role for this growth factor in the bovine foetus. (+info)
Human immunoglobulin D in colostrum, saliva and amniotic fluid.
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An antiserum raised to a partially purified preparation of secretory IgA isolated from human colostrum was shown to contain antibodies directed against human IgD. The inferred presence of IgD in the human colostrum was confirmed and also its association with antibody activity, as demonstrated by the presence of anti-E. coli antibodies. IgD was also shown to be present in whole saliva, parotid saliva and amniotic fluid, but could not be detected in jejunal juice. (+info)
Uptake and excretion of organochlorine compounds in neonatal calves.
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Intestinal absorption mechanisms of young calves change rapidly during the first 24 h postpartum and subsequently effect the absorption efficiencies of a wide range of compounds. This study was conducted to determine absorption efficiencies of (p,p'-dichlorodiphenyl)dichloroethylene (DDE), 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153), and 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD) when administered in colostrum to neonatal calves. Four male Holstein calves were given a single oral dose containing 100 mg each of DDE, PCB-153, and OCDD either 1 h (n = 2) or 65 h (n = 2) postpartum to determine whether time of exposure influenced the rate or extent of absorption. Another male calf received 100 mg each of DDE and OCDD 1 h postpartum. One gram of chromic oxide (Cr2O3) was administered as a digestion marker to dosed calves. Two male calves, receiving only colostrum, served as controls. Serum IgG concentrations indicated that the 1-h calves absorbed 20 to 37% of the ingested IgG and 65-h calves < 2%; therefore, the gut absorption mechanisms had changed by 65 h. Plasma DDE, PCB-153, and OCDD profiles did not differ based on time of exposure, suggesting that their mechanism of absorption was not influenced by the changing gut. Trapezoidal area under the curve to the last time point values indicated that, during the trial, relative plasma organochlorine concentrations amounted to PCB-153 > DDE > OCDD. Tissue concentrations were similar across treatment groups, with DDE and PCB-153 residues concentrating in adipose tissue and OCDD in the liver. Absorption efficiencies, calculated from fecal recoveries, were >97%, >74%, and >72% for DDE, PCB-153, and OCDD, respectively. These doses of DDE, PCB-153, and OCDD (2.5 +/- 0.1 mg/kg) did not produce signs of toxicosis based on detailed clinical observations, serum clinical chemistry, and gross and histological observations at necropsy. The results of this study indicate that DDE, PCB-153, and OCDD were absorbed and distributed similarly in calves exposed 1 or 65 h postpartum and did not induce toxicosis when administered in combination at these concentrations. (+info)
Soluble CD14 enriched in colostrum and milk induces B cell growth and differentiation.
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Induction of resting B cell growth and differentiation requires a complex series of temporally coordinated signals that are initiated on contact with activated helper T cells. These signals complement one another, each rendering the B cell susceptible to factors supporting progressive activation. Here, we demonstrate that soluble CD14 (sCD14) bypasses the physiological sequelae of events that limit B cell activation. B cell growth and differentiation in vitro is induced by both native and recombinant forms of sCD14 at nanomolar concentrations. sCD14-mediated cellular activation does not require membrane CD14 expression, depends on a region of CD14 that is not involved in lipopolysaccharide binding, and requires functional Toll-like receptor 4. Consistent with biological activity of sCD14 in vitro, its administration to neonatal mice enhances Ig secretion. The results presented establish sCD14 as a naturally occurring soluble B cell mitogen of mammalian origin. (+info)
Colostral neutrophils express Fc alpha receptors (CD89) lacking gamma chain association and mediate noninflammatory properties of secretory IgA.
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Colostrum plays an important role in protecting newborn infants against acute gastrointestinal and respiratory infections. IgA antibodies have been considered the major effector component; however, the role of their receptors on colostral phagocytes, especially neutrophils, has not been studied. Here, we demonstrate that CD15+ colostrum neutrophils express IgA Fc receptors (Fc alphaR, CD89) at levels similar to those of blood neutrophils. Most colostral cells (70%) bear secretory IgA (SIgA) on their surface (and intracellularly), whereas blood cells do not. The Fc alphaR on colostral neutrophils was identified as the a.1 isoform with a similar molecular mass (55-75 kDa) as that identified for blood neutrophils. Removal of N-linked carbohydrates revealed a major protein core of 32 kDa for both cell types. In contrast, co-immunoprecipitation and immunoblot experiments using a mild detergent, digitonin, revealed a lack of gamma chain association with Fc alphaR (gamma-less) exclusively on colostral neutrophils. The functional role of these gamma-less Fc alphaR cells was evaluated by measuring superoxide release and killing of SIgA-coated enteropathogenic E. coli. No increase in superoxide release was observed in colostral cells compared with blood neutrophils, whereas optimal release was obtained with PMA stimulation. Furthermore, despite similar bacterial phagocytosis index between both cell types, IgA-mediated bacterial-killing was not detectable with colostral neutrophils, whereas killing was detectable on blood cells. These results reveal exclusive expression of gamma-less Fc alphaR on colostral neutrophils associated with receptor hyperoccupation by IgA and with low, bacterial-killing activity, which suggest that this receptor may mediate noninflammatory effects of SIgA. (+info)