Concentrations of thioredoxin, a redox-regulating protein, in umbilical cord blood and breast milk

Growing evidence indicates that oxidative stress occurs during the fetal-to-neonatal transition. Such stress plays an important role in the pathogenesis of many neonatal diseases. Thioredoxin (TRX), a redox-regulating protein with antioxidant activity, is induced in various cells against oxidative stress and is secreted extracellularly. This study was undertaken to examine the clinical and biological importance of TRX in the perinatal setting. We measured concentrations of TRX in umbilical cord blood and breast milk using a sandwich ELISA. Our study demonstrated that concentrations of TRX in umbilical cord blood were six to seven times higher than those in blood of healthy adults. This study also showed that umbilical concentrations of TRX were correlated significantly with the extent of prematurity of the newborn, and that they were elevated significantly in newborns of mothers with preeclampsia compared to those of mothers without preeclampsia. In contrast, concentrations of coenzyme Q₁₀ and vitamin E in umbilical blood were lower than adult blood levels. Breast milk concentrations of TRX during the early postpartum period were seven to eight times higher than those in blood of lactating women. Those of the coenzyme Q₁₀ were lower than adult blood levels, while those of vitamin E were comparable to adult blood levels. Our findings suggest that the systemic release of TRX is enhanced at birth, and that early breast milk is a rich source of this protein. Consequent high levels of TRX in newborns may provide a unique protective mechanism that allows the maintenance of redox balance during the fetal-to-neonatal transition.     

Concentrations of thioredoxin,a redox-regulating protein,in umbilical cord blood and breast milk

Growing evidence indicates that oxidative stress occurs during the fetal-to-neonatal transition. Such stress plays an important role in the pathogenesis of many neonatal diseases. Thioredoxin (TRX), a redox-regulating protein with antioxidant activity, is induced in various cells against oxidative stress and is secreted extracellularly. This study was undertaken to examine the clinical and biological importance of TRX in the perinatal setting. We measured concentrations of TRX in umbilical cord blood and breast milk using a sandwich ELISA. Our study demonstrated that concentrations of TRX in umbilical cord blood were six to seven times higher than those in blood of healthy adults. This study also showed that umbilical concentrations of TRX were correlated significantly with the extent of prematurity of the newborn, and that they were elevated significantly in newborns of mothers with preeclampsia compared to those of mothers without preeclampsia. In contrast, concentrations of coenzyme Q₁₀ and vitamin E in umbilical blood were lower than adult blood levels. Breast milk concentrations of TRX during the early postpartum period were seven to eight times higher than those in blood of lactating women. Those of the coenzyme Q₁₀ were lower than adult blood levels, while those of vitamin E were comparable to adult blood levels. Our findings suggest that the systemic release of TRX is enhanced at birth, and that early breast milk is a rich source of this protein. Consequent high levels of TRX in newborns may provide a unique protective mechanism that allows the maintenance of redox balance during the fetal-to-neonatal transition.     

母乳和新生儿粪便细菌与母乳性黄疸的相关性分析

目的探讨母乳和新生儿粪便细菌与母乳性黄疸(BMJ)的相关性。方法以BMJ患儿为研究对象,并与健康新生儿对照。RT-PCR法检测母乳和新生儿粪便中细菌含量,比较BMJ组和对照组细菌含量的差别,分析血总胆红素与细菌含量的相关性。结果 (1)BMJ组母乳和新生儿粪便中青春双歧杆菌、两歧双歧杆菌和长双歧杆菌浓度显著低于对照组,差异均有统计学意义(均P0.01);(2)母乳两歧双歧杆菌与血清TSB显著负相关(r=-534,P=0.000);新生儿粪便青春双歧杆菌(r=-0.675,P=0.000)、两歧双歧杆菌(r=-0.598,P=0.000)和长双歧杆菌(r=-0.472,P=0.000)与血清TSB显著负相关。结论母乳中双歧杆菌含量下降可能与新生儿BMJ相关。     

Mammary origin of rat milk ribonuclease

• 1.1. When assayed under a variety of ionic conditions rat milk RNAase activity was highest under added Ca²⁺ while the serum enzyme was highest in no added ion, suggesting that milk was higher in the mammary-specific, Ca²⁺ -stimulated, RNAase than was the serum of lactating rats.
• 2.2. The acrylamide gel electrophoresis results demonstrated that milk RNAase differed from serum RNAase both in distribution and ionic preference; all milk RNAase species strongly preferred Ca²⁺ while serum RNAase species had no ionic preference.
• 3.3. The Sephacryl S200 separation accentuated these differences by showing that 98% of the total milk RNAase activity was Ca²⁺ -stimulated and clustered in a region of higher molecular weight than the serum enzyme which again had no ionic preference.
• 4.4. From these results, we conclude that the vast majority of milk RNAase molecules are not transported by the serum, but must originate in the alveolar cells.

     

Intracellular origin and secretion of milk fat globules

The cream or fat fraction of milk consists of fat droplets composed primarily of triacylglycerols that are surrounded by cellular membranes. In this review we discuss what is known about how these droplets are formed in and secreted by mammary epithelial cells during lactation. This secretion mechanism, which appears to be unique, is unlike the exocytotic mechanism used by other cell types to secrete lipids. Milk fat globules originate as small, triacylglycerol-rich, droplets that are formed on or in endoplasmic reticulum membranes. These droplets are released from endoplasmic reticulum into the cytosol as microlipid droplets coated by proteins and polar lipids. Microlipid droplets can fuse with each other to form larger cytoplasmic lipid droplets. Droplets of all sizes appear to be unidirectionally transported to apical cell regions by as yet unknown mechanisms that may involve cytoskeletal elements. These lipid droplets appear to be secreted from the cell in which they were formed by being progressively enveloped in differentiated regions of apical plasma membrane. While plasma membrane envelopment appears to be the primary mechanism by which lipid droplets are released from the cell, a mechanism involving exocytosis of lipid droplets from cytoplasmic vacuoles also has been described. As discussed herein, while we have a general overview of the steps leading to the fat globules of milk, virtually nothing is known about the molecular mechanisms involved in milk fat globule formation, intracellular transit, and secretion.     

Haloperidol secreted in breast milk.

A nursing mother was given haloperidol 5 mg twice daily for puerperal psychosis and continued to breast feed under hospital supervision. Despite considerable amounts of haloperidol being secreted in the breast milk (up to 23.5 micrograms/l), the infant was apparently not sedated, fed well, and continued to thrive. The findings suggest that maternal ingestion of haloperidol for short periods has no deleterious effect on the infant''s development.     

n-acetyl-beta-hexosaminidase activity in human breast milk

1. The lysosomal enzyme, N-acetyl-beta-hexosaminidase (HEX) is present in human breast milk. It is composed predominantly of "A" (heat-labile) and "B" (heat-stable) isozymes which coelute with the corresponding major serum isozymes on DE-52 ion-exchange chromatography. 2. Total HEX activity in "early" milk obtained at 2.8 +/- 1.4 weeks post partum, is approx. 2.5-fold higher (87 +/- 29 nmol/60'/mg protein. n = 10) than that of pregnancy serum (35.7 nmol/60'/mg protein) prior to delivery. 3. These levels increase to greater than 3-fold (110 +/- 20 nmol/60'/mg protein, n = 13) as the milk matures (10.3 +/- 4.2 weeks). 4. The specific activity of HEX A in the milk changes little with time post partum, because absolute 5. In contrast, HEX B specific activity is increased, as absolute levels (per volume) remain constant in the face of decreasing milk protein content, 5. These changes result in a high degree of correlation (r = 0.81) between time of lactation and % HEX A observed.     

The inhibitory activity of Lactobacillus spp. isolated from breast milk on gastrointestinal pathogenic bacteria of nosocomial origin

Milk acts as a mean for transporting many essential substances from the mother to the child. In human beings, milk includes several predominant bacteria, such as staphylococci, streptococci, micrococci, lactobacilli, enterococci, lactococci and bifidobacteria. Besides, its intake favors the predominance of bifidobacteria and lactobacilli in the child’s intestinal microbiota. The present work explores the isolation and selection of lactobacilli strains with probiotic potential, focusing in their degree of hydrophobicity and antagonism against important gastrointestinal nosocomial pathogens. 98 lactobacilli were isolated from 48 breast milk samples, with most strains belonging to the obligately homofermentative group (36.7%). 63% of the isolated strains showed a high degree of hydrophobicity when tested on three solvents and were selected for detecting antimicrobial activity against gastrointestinal pathogens, including Escherichia coli, Shigella spp, Pseudomonas spp and Salmonella spp strains. When applying the agar diffusion test, many isolated strains presented inhibitory activity against pathogenic strains. We observed that: Salmonella enteriditis was the most inhibited pathogen, and the strains with the most inhibitory power were AR2 and O1 (both highly hydrophobic lactic acid bacteria), which showed an opposing effect against all nosocomial pathogens tested. Although more in vitro, in vivo or clinical data would be needed before any conclusion on the probiotic properties of the strains can be drawn, our results demonstrate that some of the tested strains may have good probiotic potential for their inclusion in products targeting infants.