人乳游离氨基酸的含量及动态变化

本文报道了南京城区90份不同哺乳期(1～42d)母乳中游离氨基酸的含量。结果表明:人乳中最丰富的游离氨基酸是谷氨酸,其次是牛磺酸。人乳中的必需游离氮基酸在初乳中含量最高,以后随泌乳时间的延长而下降。文中讨论了人乳游离氨基酸在婴儿早期喂养中的作用。本研究为提倡母乳喂养和配制人乳化的婴儿食品提供了科学依据。     

早产儿和足月儿母乳及牛乳铜铁锌含量测定

用原子吸收分光光度计火焰法测定产后4周内早产儿母乳、足月儿母乳及牛乳的铜、铁、锌含量。早产儿和足月儿母乳中三种微量元素的含量均随产后周龄延长而降低,二者间无显著性差异。早产儿母乳铜含量、产后第1周铁含量显著高于牛乳。计算出的平均摄入量与推荐量比较,早产儿母乳铜、铁、锌营养价值优于牛乳。     

人奶、牛奶和新生儿配方奶中的表皮生长因子水平

目的　证实母乳EGF分泌量的变化是对早产儿加速生长和成熟的一种适应性反应；比较人乳、新鲜牛奶以及新生儿奶配方中的EGF含量.方法　使用放射免疫分析法,测定了57份人初乳（分别来自分娩早产儿和足月儿的母亲）、4种新鲜牛奶和8种基于牛奶的新生儿配方奶中的EGF含量. 结果　早产儿奶的EGF水平（28.2±10.3?nmol/L）明显高于足月儿奶（17.3±9.6?nmol/L）.母乳EGF含量与其分娩的新生儿胎龄和出生体重呈负相关.新鲜牛奶的EGF水平（13.8-18.2?nmol/L）与足月儿奶相当,但低于早产儿奶.非水解蛋白质配方奶的EGF浓度明显低于人奶和新鲜牛奶.水解蛋白质配方奶的EGF浓度在可测范围之下. 结论　早产儿奶中EGF的高含量可能代表着一种与早产儿加速的生长发育相适应的代偿机制；由于配方奶中的EGF不足甚至缺乏,故应提倡用母乳喂养自己的婴儿.     

谷氨酰胺在胃肠肿瘤患者术后的应用进展

谷氨酰胺(glutamine,Gln)是血液循环和组织内游离氨基酸池中含量最丰富的一种氨基酸,既能为氨基酸、蛋白质、核酸的合成提供氮源,又能被氧化释放能量。Gln是一种特殊的营养物质,是一种条件性必需氨基酸,约占全身游离氨基酸的60%,它是血浆中含量最高的氨基酸,正常血浆浓度为0.6~0.9 mmol/L。近年来,随着临床营养领域研究的不断深入,单纯的营养支持已逐步转为免疫营养治疗的概念。Gln能够提     

谷氨酰胺抑制肠道粘膜萎缩

<正> 谷氨酰胺是体内含量丰富的氨基酸,约占骨骼肌、肝脏氨基酸总含量的60％,营养输液时谷氨酰胺是必不可少的。谷氨酰胺可由体内合成,在血中游离氨基酸中浓度很高。近年来,谷氨酰胺抑制肠道粘膜萎缩的     

谷氨酰胺在临床疾病中的应用

谷氨酰胺（Glutamine,Gln）是体液中最丰富的氨基酸之一,占总游离氨基酸的61%,其中75%存在于骨骼肌中。其血浓度为0.5～0.9mmol/l,约占所释放氨基酸总量的1/3。在骨骼肌和能合成并储存谷氨酰胺的器官中的浓度是血液中可循环浓度的30倍。虽然谷氨酰胺在体内组织中的含量很大,但其缺乏会引起很多疾病,     

抑制谷氨酰胺合成酶对小鼠纹状体氨基酸类和单胺类递质含量的影响

目的：探讨抑制谷氨酰胺合成酶对小鼠纹状体氨基酸类递质和单胺类递质稳态的影响。方法：3月龄C57BL/6J小鼠,腹腔给予谷氨酰胺合成酶抑制剂L-蛋氨酸磺酸盐0.1 mL/10 g,隔日给药,持续2周。Western blot方法检测纹状体谷氨酰胺合成酶以及谷氨酸转运体蛋白表达水平,高效液相色谱法检测纹状体谷氨酸、谷氨酰胺等氨基酸类递质和多巴胺、5-羟色胺等单胺类递质的含量。结果：同生理盐水对照组相比,实验组小鼠纹状体谷氨酸转运体1、谷氨酸天冬氨酸转运体表达上调,谷氨酰胺合成酶表达下调;谷氨酸、谷氨酰胺、天冬氨酸含量减少,γ-氨基丁酸、丝氨酸含量增加,而单胺类递质含量无明显变化。结论：系统性给予谷氨酰胺合成酶抑制剂能影响脑内氨基酸类递质代谢的稳态,导致兴奋性神经递质谷氨酸水平下降,抑制性神经递质γ-氨基丁酸水平上升,但对单胺类递质含量没有影响。     

谷氨酰胺在肠外营养的应用

谷氨酰胺(Glutamine,Gln)是人体血浆和组织中含量最丰富的游离氨基酸,约占总游离氨基酸的50%[1]。Gln是条件必需氨基酸,也称半必需氨基酸,参与机体内各种代谢和合成的生化过程[2],具有多种重要的生理功能,是人体内一种非常重要的     

母乳中尿酸的检测及其临床意义

目的了解足月儿母初乳、成熟乳及早产儿母初乳中尿酸的含量及其临床意义.方法用尿酸酶-过氧化酶法测定足月儿母初乳、成熟及早产儿母初乳乳清中尿酸的含量,并进行比较.结果足月儿母初乳中尿酸含量明显高于成熟乳,早产儿与足月儿母初乳中尿酸含量无显著性差异.结论尿酸作为一种抗氧化物质,可能在保护母乳多不饱和脂肪酸免于自由基过氧化反应以及保护新生儿肠道粘膜完整性方面起重要作用.     

谷氨酰胺的临床应用

谷氨酰胺(Glutamine,Gln)是体内含量最丰富的非必需氨基酸,约占血液游离氨基酸的60%.正常情况下,肌肉等组织可大量合成,所以它被视为非必需氨基酸.当人体处于应激状态,例如外伤、手术、烧伤、感染或糖皮质激素治疗时,体内各个器官都加快了对Gln的代谢,从而导致机体储备的Gln下降,当体内逐渐耗竭,而内源性合成的Gln又不能满足机体的需要时,Gln就成为一种条件必需氨基酸.Gln是合成氨基酸、蛋白质、核酸和许多其它生物分子的前体物质,在肝、肾、小肠和骨骼肌代谢中起重要的调节作用,是机体内各器官之间转运氨基酸和氨的主要载体,也是生长迅速细胞的主要燃料.     

母乳及配方奶对出院后早产儿生长发育影响的研究

目的探讨早产儿母乳、早产儿配方奶及普通足月儿配方奶对早产儿出院后家庭喂养条件下生长发育的影响。方法将210例早产儿随机分为早产儿母乳组、早产儿配方奶组及普通足月儿配方奶组,观察三组早产儿生后矫正胎龄6个月时的生长发育情况。结果早产儿母乳组与早产儿配方奶组早产儿体重、身长、头围的差异无统计学意义（P〉0.05）,但较普通足月儿配方奶组差异有统计学意义（P〈0.05）,早产儿母乳组神经行为发育与早产儿配方奶组及普通足月儿配方奶组相比,差异有统计学意义（P〈0.05）。结论生后矫正胎龄6个月时早产儿配方奶喂养早产儿在体重、身长及头围方面能与早产儿母乳喂养取得相同效果,且均较普通足月儿配方奶喂养效果好,早产儿母乳喂养早产儿在神经行为发育方面优于早产儿配方奶及普通足月儿配方奶喂养。     

Epidermal growth factor concentrations in human milk, cow’s milk and cow ’s milk-based infant formulas

Objective Because maternal epidermal growth factor (EGF)may be an adaptive response to a ccelerate growth and maturation in premature infants, we compared the EGF conten t in fresh cow’s milk and cow’s milk-based infant formulas with full and prete rm mother’s milk. Methods EGF content of 57 human colostrum from mothers delivering prematurely a nd at term, 4 different fresh cow’s milk and 8 different cow’s milk-bas ed infant formulas was determined by radioimmunoassay (RIA). Results Human milk from mothers of premature infants had a higher EGF content compared t o that from mothers of term infants (28.2±10.3nmol/L vs 17.3±9.6nmol/L ). EGF content in human milk negatively correlated with gestational age and bir th weight of neonates. EGF content in fresh cow’s milk (13.8-18.2nmol/L) wa s similar to that in human term milk. EGF levels in non-hydrolyzed protein for mulas were much lower (5.6-8.6nmol/L), and were undetactable in hydrolyzed p rotein formulas. Conclusion The high EGF content in premature milk may represent a maternal compensatory mec hanism to accelerate the growth and development of immature infants. Feeding in fants with breast milk from their own mother should be advocated since there is lack of EGF in cow’s milk-based infant formulas.     

Experience of early breast milk feeding in preterm very low birth weight infants

Although human milk is generally accepted as the gold standard for the feeding of term infants, its use in the preterm and very low birth weight (VLBW) infants particularly in the initial period of birth has been more controversial. Little is known about the risks and benefits of early introduction of breast feeding on preterm VLBW infants. The primary object of this study was to evaluate the safety and benefit of early breast milk feeding in preterm VLBW newborns during their initial hospitalization periods. Therefore a prospective observational study was conducted among 37 preterm VLBW infants who were admitted to the Neonatal ward of Sir Salimullah Medical College and Mitford Hospital during the period of February 15th to July 25th, 2003. Oral feeding with breast milk was started within one hour of birth, and weight gain, feeding tolerance, nosocomial infection rate as well as other associated problems of pre-maturity, and postnatal growth curve were recorded upto 16th postnatal day. Seventy three percent of the newborns tolerate breast milk well from the very beginning, and the rest did not tolerate initially but all of them tolerate within 24 hours of birth. Infants had less initial weight loss (20 ± 10 gm) and faster recovery of birth weight. They regained their birth weight at 12th postnatal day. Hyper-bilirubinaemia was found in only 22% cases, and was observed in the group who initially didn't tolerate breast milk and was on intravenous fluid. Nobody developed symptomatic hypoglycemia or necrotizing enterocolitis (NEC). Two cases of sepsis and another two cases of minor infection like conjunctivitis and oral thrush have occurred. In conclusion it can be said that early breast milk feeding is safe in preterm VLBW infants and it helps to promote growth and reduce the need for intravenous line.     

哈蟆油发酵乳中蛋白质及氨基酸含量分析

目的：建立哈蟆油发酵乳中蛋白质及氨基酸含量分析方法。方法运用考马斯亮蓝法测定哈蟆油发酵乳中蛋白质含量,运用氨基酸自动分析仪测定哈蟆油发酵乳中氨基酸的含量。结果3批哈蟆油发酵乳蛋白含量分别为8.0501、8.0930、7.7582 mg/mL。平均总氨基酸的含量为15.3205 mg/mL。结论哈蟆油发酵乳中含有合成人体所需蛋白质及丰富的氨基酸。     

Latent anaphylactic sensitisation of infants of low birth weight to cows' milk proteins

Latent systemic anaphylactic sensitisation to cows' milk was assessed in 61 preterm infants who were randomly assigned to receive either a special formula for preterm infants based on cows' milk or banked breast milk or one or other of these as a supplement to maternal milk. A single sample of venous blood was taken near to the time of discharge from the neonatal intensive care unit, and the histamine release by blood basophils in response to in vitro challenge with cows' milk and anti-IgE was measured. Compared with the blood from infants fed on human milk, that from infants fed on preterm formula showed a significant increase in histamine release to challenge with cows' milk, the response being greater in blood from infants of lower birth weight and gestational age. A smaller but significant increase in blood histamine release with anti-IgE challenge was observed in the group fed on preterm formula. Infants of low birth weight fed on preterm formula based on cows' milk may develop latent systemic sensitisation more rapidly than infants born at term. The clinical importance of this requires further investigation.     

Umbilical and maternal amino acid concentrations in appropriate and small for gestational age infants]

Serum amino acid concentrations were determined in 63 pregnant women and their infants at delivery. Samples were obtained from 47 appropriate for gestational age infants (AGA) and 16 small for gestational age infants (SGA). The SGA group had significantly lower concentrations of total amino acid, compared with those of AGA, in both the umbilical and maternal blood. The essential amino acids of the cord, such as isoleucine and threonine, and maternal essential amino acids like threonine and arginine in the SGA group were lower than those in the AGA group. In contrast, nonessential amino acid concentrations, such as alanine, proline and aspartic acid were significantly higher in the umbilical blood of the SGA infants, while there were no differences in the maternal blood of both AGA and SGA groups. There was a positive relationship between maternal and umbilical total amino acid concentrations in the AGA group, but no relationship exists in the SGA group.     

Nutrient composition of milk produced by mothers of preterm infants in Nigeria

Nutrient composition was determined in breast milk obtained by manual expression from 12 mothers who delivered prematurely (mean 32 weeks) and 15 mothers who delivered at term (mean 39.4 weeks), on days 3, 7, 14, 21 and 28 postpartum. Complete 24-hour milk expressed by five term mothers and seven preterm mothers on days 7, 14, 21 and 28 lactational ages was also recorded. In both preterm and term mothers' milk, lactose and fact concentrations increased with lactational age, while protein and mineral concentrations decreased. The preterm mothers' milk contained higher concentrations of protein, fat and minerals and lower concentrations of lactose than term mothers's milk. The fat and caloric density of milk of the mothers in this study, who were mostly of low social class, was lower than that reported from Western countries. The implication of this finding for feeding premature infants in developing countries is discussed.     

母婴分离诱导子代抑郁大鼠肠道氨基酸代谢失调

目的：探索母婴分离诱导产后子鼠的抑郁样行为及对小肠氨基酸和氨基酸转运体的影响。方法：采用母婴分离建立子鼠抑郁模型,将 SD 母鼠随机分为对照组（n=8）和母婴分离组（n=8）。对照组母鼠在产后不进行任何干预。母婴分离组的母鼠在正常分娩后与子鼠连续分离14?d,每天分离3?h。采用糖水偏好实验、新奇抑制摄食实验及强迫游泳实验评估子鼠的抑郁样行为。采用氨基酸分析仪检测子鼠小肠中氨基酸的变化,通过蛋白质印迹法检测子鼠肠道中性氨基酸转运蛋白 ASCT2、B⁰AT1和LAT1的表达。结果：与对照组比较,母婴分离组子鼠的体重在出生后第21天和28天减轻（t=4.925和 5.766,均P<0.01）,糖水偏好百分比减小（t=2.709,P<0.05）,摄食潜伏期延长（t=–13.431,P<0.01）,强迫游泳实验中的不动时间延长（t=–3.616,P<0.01）。与对照组比较,母婴分离组子鼠小肠中的天冬氨酸浓度增加（t=–6.672,P<0.01）,谷氨酰胺和甘氨酸浓度减小（t=3.107 和 9.781,均P<0.01）,同时 ASCT2 和 B⁰AT1 蛋白表达减少（t=6.734和9.015,均P<0.01）,而 LAT1 蛋白表达增加（t=–8.942,P<0.01）。结论：母婴分离诱导子鼠产生抑郁样行为,同时其小肠氨基酸浓度发生变化,肠道氨基酸转运体表达改变,提示肠道氨基酸功能失调与母婴分离诱导的抑郁样行为可能相关。