铁负荷过重对淋巴细胞转铁蛋白受体表达的影响

本研究采用体外细胞培养、ＡＢＣ－ＲＬＩＳＡ法、ＲＮＡ斑点杂交和原子吸收光谱分析等技术方法，观察了高浓度柠檬酸铁对健康人外周血淋巴细胞转铁蛋白受体（ＴｆＲ）及其基因表达的影响。结果显示：高铁负荷组比正常对照组ＴｆＲ减少了２２％、３８％和６１％（Ｐ＜０．０１），且ＴｆＲｍＲＮＡ水平也随着基质中铁浓度的增高而降低。细胞内铁浓度与ＴｆＲ数量变化呈显著负相关（ｒ＝－０．９７６８，ｎ＝６，Ｐ＜０．０５），说明铁负荷过重可下向调节淋巴细胞ＴｆＲ及其基因表达。     

铁缺乏时淋巴细胞增殖反应改变的实验研究

本研究采用体外细胞培养，３Ｈ－Ｔｄｒ掺入，原子吸收光谱分析等技术方法，观察了低浓度Ｆｅ－ｃｉｔ时淋巴细胞内铁浓度变化及经ＣｏｎＡ、ＰＨＡ诱导的细胞增殖反应能力改变，结果显示：铁缺乏时（第２、３、４组）ＳＩ降低，与正常组（第１组）比较相差非常显著（Ｐ＜０．０１），ＳＩ与细胞内铁浓度的变化呈显著正相关（Ｐ＜０．０５，ｒ１＝０．９４６６，ｒ２＝０．９３３９），说明铁缺乏时淋巴细胞增殖反应能力受抑。     

138例医用X线工作者外周血象分析

本文统计分析了我区１３８例医用Ｘ线工作者外周血象（白细胞，血小板计数）二项指标。其均值低于健康成人血象，探讨了影响其有关因素，发现放射工龄（Ｘ１）；个人累积剂量当量（Ｘ２）呈负相关关系。相关系数分别为ｒＹ１＝－０．４７１（Ｐ〈０．００１）；ｒＹ２＝－０．４５１（ｐ〈０．００１）；ｒＹ１＝－０．６８６８（ｐ〈０．００１）ｐ；ｒＹ２＝－０．６５９（Ｐ〈０．００１）。进一步计算了它们之间的偏相关系数，强     

血清铜锌及硒水平与肝癌患者的预后

测定４６例原发性肝癌患者的血清Ｃｕ、Ｚｎ、Ｓｅ及Ｃｕ／Ｚｎ比值，与对照组比较：血清Ｚｎ、Ｓｅ水平明显低于对照组（Ｐ＜０．０１，Ｐ＜０．００１）；而Ｃｕ及Ｃｕ／Ｚｎ比值则高于对照组（Ｐ均＜０．００１）；而且血清Ｃｕ水平与患者病期有关，并与患者生存天数呈相关关系（ｒ＝－０．７２４）     

支气管哮喘血浆内皮素含量变化观察分析

本文采用特异性放免技术测定７０例支气管哮喘急性发作（发作组）、临床控制（缓解组）和１０名健康对照者（对照组）的血浆内皮素（ＥＴ）含量。结果显示：发作组血浆含量（１１６±３．６）ｎｇ／Ｌ分别显著高于缓解组［（６８±２．７）ｎｇ／Ｌ，Ｐ＜０．０１］和对照组（５０±７．３２）ｎｇ／Ｌ；而缓解组和对照组间的差异无显著性；发作组血浆ＥＴ含量分别与血氧分压（ＰａＯ２）及一秒用力呼气容积占用力肺活量比值（ＦＥＶ１％）呈显著负相关（ｒ＝－０．７１７，ｒ＝－０．７０１６，Ｐ＜０．０１）与峰流速变异率（ＰＥＦ％）呈显著正相关（ｒ＝０．６３６４，Ｐ＜０．０１）。上述结果提示ＥＴ参与支气管哮喘急性发作的病理生理过程     

补硒对低硒居民血小板活化状态的影响

应用１２５Ｉ标记放免法测定血浆血栓素（ＴＸＡ２）、前列环素（ＰＧＩ２）和血小板ＴＸＡ２生成，以比浊法和ＥＬＩＳＡ分别测定血小板聚集性和β－血小板球蛋白（βＴＧ），电镜观察血小板形态，对比研究补硒（２００μｇＳｅ／ｄ，亚硒酸钠，１２周）和未补硒低硒居民上述参数的变化。用２，３－二氨基萘荧光法和谷胱甘肽还原酶偶联法测定硒含量和谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性。结果表明，补硒使红细胞硒和ＧＳＨ－Ｐｘ活性显著增高（Ｐ＜０．０１）；血浆ＴＸＡ２、ＴＸＡ２／ＰＧＩ２比值及血小板ＴＸＡ２生成和聚集性均显著低于未补硒组（Ｐ＜０．０１或０．０５），但血浆ＰＧＩ２和βＴＧ含量以及血小板βＴＧ含量和释放率无显著改变（Ｐ＞０．０５）；补硒可明显减轻病区低硒居民血小板的形态变化，使α－颗粒数显著高于未补硒组（Ｐ＜０．０１）；红细胞硒或ＧＳＨ－Ｐｘ活性分别与血浆ＴＸＡ２和血小板ＴＸＡ２生成呈显著负相关（ｒ＝－０．６９６，－０．７８０；－０．６７６和－０．７９６，Ｐ＜０．０１），与ＡＤＰ诱导的血小板聚集性显著负相关（ｒ＝－０．３９０，－０．３７２，Ｐ＜０．０５）；与凝血酶诱导的聚集性呈不显著的负相关（ｒ＝－０．２７９，－０．３０９?     

煤尘,矽尘对血液中性粒细胞碱性磷酸酶和过氧化物酶的影响

采用血细胞组织化学方法，对接触煤尘，矽尘工人及尘肺病人血液中性粒细胞（ＰＭＮ）碱性磷酸酶（ＡＫＰ）和过氧化物酶（ＰＯＸ）进行测定，结果显示，煤尘和矽尘均可致血液中性粒细胞的ＡＫＰ升高（Ｐ〈０．０１）ＰＯＸ降低（Ｐ〈０．０１），接触煤尘和矽尘工龄与ＡＫＰ和ＰＯＸ的相关分析表明，接尘工龄与ＡＫＰ和ＰＯＸ呈负相关关系（煤尘ｒ＝－０．３７７４，ｒ＝－０．２６９９，矽尘ｒ＝－０．２４０１，ｒ＝－０．２２７２     

人类精子DNA氧化损伤与精子质量和精液中镉、铅浓度的关系

用高压液相色谱—光电检测系统和高压液相色谱—紫外线检测器同时检测发现人精子ＤＮＡ８ＯＨｄＧ 和ｄＧ 水平,用原子吸收光谱检测精液中镉、铅浓度。确定５６ 名非吸烟者精子ＤＮＡ８羟脱氧核糖核酸（８ＯＨｄＧ） 水平,探讨人类精子ＮＤＡ氧化性损伤与精子质量和精液中镉、铅浓度的关系。发现８ＯＨｄＧ／１０６ｄＧ平均几何均数为４８．３（９５ ％ ＣＩ：２０．８ － １１１．８ ,ｎ ＝ ５６） ;８ＯＨｄＧ／１０６ｄＧ 与精子密度（ｒ＝ － ０．４６ ,Ｐ＝ ０．００１ ,ｎ ＝ ５６） 和精子总数之间（ｒ＝ － ０．３７ ,Ｐ＝ ０．００５ ,ｎ ＝ ５６） 呈明显的负相关;８ＯＨｄＧ／１０６ｄＧ 与精液镉（ｒ＝ ０．４９ ,Ｐ＝ ０．００１） 、铅（ｒ＝ ０．３０ 、Ｐ＝ ０．０２５） 浓度呈明显的正相关。提示人类精子氧化性损伤影响精子质量,精液中镉、铅浓度可能是人类精子氧化性损伤的重要因素     

大鼠全血核黄素HPLC测定及其初步应用

为探讨核黄素营养状况评价的直接指标血液核黄素浓度，本文建立了大鼠全血核黄素的ＨＰＬＣ测定方法。其重复性，ＣＶ＝３．２％，回收率为８９．９％，全血核黄素与全血谷胱甘肽还原酶活性系数呈负相关，ｒ＝－０．７９５９，Ｐ＜０．００１。提示本方法可用于大鼠核黄素营养状况的评价。     

Ⅱ型糖尿病伴发冠心病患者血清脂质与丙二醛变化的临床观察

观察了４０例Ⅱ型糖尿病（ＮＩＤＤＭ）伴发冠心病（ＣＨＤ）患者及３２例ＮＩＤＤＭ无心脑肾并发症患者（对照组）血脂水平及丙二醛（ＭＤＡ）和超氧化物歧化酶（ＳＯＤ）的血清含量，结果显示，除胆固醇外，其余各指标两组间均有显著差异。ＣＨＤ组ＭＤＡ明显高于对照组，而ＳＯＤ则明显低于对照组。多元线性相关分析表明，低密度脂蛋白胆固醇与ＭＤＡ呈显著正相关（ｒ＝０．５７１２；Ｐ＜０．００１）。高密度脂蛋白胆固醇与ＳＯＤ呈显著正相关（（ｒ＝０．５１１２；Ｐ＜０．００１）。提示ＮＩＤＤＭ患者伴发冠心病高脂血症与脂质过氧化间有一定的关系。     

Increasing the cooking temperature of meat does not affect nonheme iron absorption from a phytate-rich meal in women

The effect of increasing cooking temperatures of meat on nonheme iron absorption from a composite meal was investigated. Cysteine-containing peptides may have a role in the iron absorption enhancing effect of muscle proteins. Heat treatment can change the content of sulfhydryl groups produced from cysteine and thereby affect iron absorption. Twenty-one women (25 +/- 3 y) were served a basic meal without meat and two other meals consisting of the basic meal plus 75 g of pork meat cooked at 70, 95 or 120 degrees C. The meals were extrinsically labeled with (55)Fe or (59)Fe. Iron absorption was determined from measurements of whole-body (59)Fe retention and the activity of (55)Fe and (59)Fe in blood samples. Nonheme iron absorptions were 0.9 (0.5-4.0)% (P = 0.06), 0.7 (0.4-3.9)% (P = 0.1) and 2.0 (1.3-3.1)% (P < 0.001) greater when meat cooked at 70, 95 or 120 degrees C, respectively, was added to the basic meal. Increasing the cooking temperature of meat did not impair nonheme iron absorption compared with cooking at 70 degrees C. Because the cysteine content of meat decreased with increasing cooking temperature, this argues against a specific contribution of sulfhydryl groups from cysteine residues in the promotion of nonheme iron absorption by meat proteins.     

Low-pH cola beverages do not affect women's iron absorption from a vegetarian meal

Preliminary data in the literature indicate that iron absorption from a meal may be increased when consumed with low-pH beverages such as cola, and it is also possible that sugar iron complexes may alter iron availability. A randomized, crossover trial was conducted to compare the bioavailability of nonheme iron from a vegetarian pizza meal when consumed with 3 different beverages (cola, diet cola, and mineral water). Sixteen women with serum ferritin concentrations of 11-54 μg/L were recruited and completed the study. The pizza meal contained native iron and added ferric chloride solution as a stable isotope extrinsic label; the total iron content of the meal was ~5.3 mg. Incorporation of iron from the meal into RBC was not affected by the type of drink (9.9% with cola, 9.4% with diet cola, and 9.6% with water). Serum ferritin and plasma hepcidin were correlated (r = 0.66; P<0.001) and both were significant predictors of iron bioavailability, but their combined effect explained only 30% of the inter-individual variation (P<0.001) and illustrates the current lack of understanding of mechanisms responsible for the fine-tuning of iron absorption. Although there was no effect of low-pH drinks on iron bioavailability in healthy women, their effect on absorption of fortification iron that requires solubilization in dilute acid, such as reduced iron, and in individuals with low gastric acid production, such as older people and individuals with Helicobacter pylori infection, warrants further investigation.     

L-alpha-glycerophosphocholine contributes to meat's enhancement of nonheme iron absorption

In this research, our aim was to isolate and characterize the substance known as "meat factor," which is reported to enhance nonheme iron absorption. We used various analytical techniques, and the final step was a human study to measure the effect of a candidate compound on iron absorption. Lean beef was selected for study, as it is known to increase nonheme iron absorption. Cooked ground beef was homogenized and aliquots were taken through a simulated gastric and intestinal digestion. This was followed by purification using fast protein liquid chromatography. The fractions were collected and applied to a Caco-2 cell system designed to measure iron absorption using radioiron. Fractions with an enhancing effect were analyzed by mass spectrometry, nuclear magnetic resonance, and HPLC, and a proposed empirical formula was obtained for the substance in the most active fraction (C(8)H(20) NO(6)P). Tandem mass spectrometry was used to identify the compound as L-alpha-glycerophosphocholine (L-alpha) by comparing the spectra against authentic material. We added a commercially available food grade source of L-alpha to vegetarian lasagna, with and without 100 mg ascorbic acid (a known enhancer of nonheme iron absorption), at the same enhancer:iron molar ratio (2:1), and fed meals to 13 women of child-bearing age with low iron stores. The nonheme iron was labeled with stable isotopes of iron to provide a total dose per meal of 10 mg iron, and absorption was measured from erythrocyte incorporation. Nonheme iron absorption from lasagna was increased by the addition of either ascorbic acid (P = 0.010) or L-alpha (P = 0.023). We have identified L-alpha as a component of muscle tissue that enhances nonheme iron absorption, and this finding provides new opportunities for iron fortification of foods.     

Pork meat increases iron absorption from a 5-day fully controlled diet when compared to a vegetarian diet with similar vitamin C and phytic acid content

Meat increases absorption of non-haem iron in single-meal studies. The aim of the present study was to investigate, over a 5 d period, the potential increasing effect of consumption of pork meat in a whole diet on the fractional absorption of non-haem iron and the total absorption of iron, when compared to a vegetarian diet. A randomised cross-over design with 3 x 5 d whole-diet periods with diets containing Danish-produced meat, Polish-produced meat or a vegetarian diet was conducted. Nineteen healthy female subjects completed the study. All main meals in the meat diets contained 60 g of pork meat and all diets had high phytic acid content (1250 mumol/d). All main meals were extrinsically labelled with the radioactive isotope (59)Fe and absorption of iron was measured in a whole body counter. The non-haem iron absorption from the Danish meat diet was significantly higher compared to the vegetarian diet (P=0.031). The mean fractional absorption of non-haem iron was 7.9 (se1.1), 6.8 (se 1.0) and 5.3 (se 0.6) % for the Danish and Polish meat diets and vegetarian diet, respectively. Total absorption of iron was higher for both meat diets compared to the vegetarian diet (Danish meat diet: P=0.006, Polish meat diet: P=0.003). The absorption ratios of the present study were well in accordance with absorption ratios estimated using algorithms on iron bioavailability. Neither the meat diets nor the vegetarian diets fulfilled the estimated daily requirements of absorbed iron in spite of a meat intake of 180 g/d in the meat diets.     

Meat consumption in a varied diet marginally influences nonheme iron absorption in normal individuals

It is widely recognized that the intake of animal foods is the most important dietary determinant of the iron status of a population. The primary reason is the high bioavailability of heme iron, but it is also known from radiolabeled single-meal feeding studies in humans that muscle tissue facilitates absorption of nonheme iron. In the present study, we examined the effect of meat intake on nonheme iron absorption from a whole diet. Iron absorption was measured during 3 separate dietary periods in 14 volunteers (7 men and 7 women) by having them ingest a radioiron-labeled wheat roll with every meal for 5 d. The diet was freely chosen for the first dietary period and altered to eliminate or maximally increase the intake of muscle foods during the second and third periods. Nonheme iron absorption did not differ for the 3 dietary periods although the geometric mean of 4.81% when subjects consumed a freely chosen diet increased by 35% to 6.47% with maximum meat consumption (P = 0.075). When nonheme absorption was adjusted to normalize for differences in iron status using serum ferritin correction and the 3 absorption periods were pooled, multiple regression analysis indicated no significant relation with heme or nonheme iron, vitamin C, calcium, phosphorus, fiber, or tea content of the diet with the exception of animal tissue (P = 0.013). We conclude that the higher iron status associated with the consumption of an omnivorous diet is due more to the intake of heme iron than to the enhancing effect on nonheme iron absorption.     

Can we cut out the meat of the dish? Constructing consumer-oriented pathways towards meat substitution

The shift towards a more sustainable diet necessitates less reliance on foods of animal origin. This study presents data from a representative survey of Dutch consumers on their practices related to meat, meat substitution and meat reduction. The practices reflected a cultural gradient of meat substitution options running from other products of animal origin and conventional meat free meals to real vegetarian meals. To investigate feasible substitution options, a variety of meals without meat were presented using photos, which were rated by the participants in terms of attractiveness and chances that they would prepare a similar meal at home. The results demonstrated the influence of meal formats, product familiarity, cooking skills, preferences for plant-based foods and motivational orientations towards food. In particular, a lack of familiarity and skill hampered the preparation of real vegetarian meals. Based on the findings we propose a diversified understanding of meat substitution and we specify four policy-relevant pathways for a transition towards a more plant-based diet, including an incremental change towards more health-conscious vegetarian meals, a pathway that utilizes the trend towards convenience, a pathway of reduced portion size, and practice-oriented change towards vegetarian meals.     

Iron absorption in humans: bovine serum albumin compared with beef muscle and egg white

We studied the influence of bovine serum albumin and beef meat on nonheme iron absorption in humans and on dialyzable iron in vitro. The addition of serum albumin to a maize gruel had no significant effect on nonheme Fe absorption whereas the addition of beef meat caused a threefold increase. When added to a bread meal, serum albumin caused a modest 60% increase in nonheme Fe absorption and beef meat had no effect. When added to a protein-free meal, serum albumin reduced Fe absorption by 47% compared with a 72% reduction on addition of egg white. The bioavailability of nonheme Fe from meals containing serum albumin was consistently overestimated by the in vitro technique. We conclude that the facilitation of nonheme Fe absorption by meat is not a general property of all animal protein but is better explained by the action of one or more specific animal tissues.     

Statistical model for predicting non-heme iron bioavailability from vegetarian meals

Availability of non-heme iron has been extensively discussed when meals comprise heme as well as non-heme iron, but seldom so for exclusively vegetarian meals. The present study aimed to develop a statistical model for predicting non-heme iron availability from a composite vegetarian meal. Radioisotopic measurements of in vitro iron dialyzability of 208 out of 274 meals representing vegetarian diets from Asia, Africa, Europe and Latin America and the meal contents of iron, zinc, copper, ascorbic acid, beta-carotene, riboflavin, thiamin, folic acid, tannic acid, fiber and degraded phytate forms (IP6-IP1) were used for development of the model. A multiple regression model weighted for calorie contents was developed for the percentage iron dialyzability with the possible predictors as meal contents along with plausible interaction terms. The model was validated with in vitro iron dialyzability of 66 meals and in vivo iron absorption in five ileostomized adults. Application of the model was demonstrated using data on the daily dietary intake of 215 young adults whose hemoglobin levels were estimated twice in 3 weeks. Weighted multiple regression model was: ln(% Fe dialyzability)=1.340-0.259xln(IP2 [mg])+0.188xln(IP3 [mg])-0.278xln(IP5 [mg])+0.0912xln(ascorbic acid [mg])+0.06693xln(tannins [mg])+0.09552xln(beta-carotene [microg])+0.137xln(hemicellulose [g]) (P<0.01, R2=0.51). Good agreement was seen between observed and predicted dialyzability (r=0.90) and human absorption (r=0.89). The model would be useful to estimate bioavailable iron intakes of vegetarian populations and to identify at-risk individuals.     

Adequacy of a vegetarian diet at old age (Dutch Nutrition Surveillance System)

To assess the adequacy of a vegetarian diet at old age, the dietary intake (assessed through dietary history with cross-check) of 44 apparently healthy lacto-(ovo-)vegetarians, aged 65-97 years, was evaluated. Adequacy was assessed by a comparison of nutrient intake with (Dutch) recommendations and by evaluating data on nutritional status. The results were also compared with data of elderly omnivores. In contrast to elderly omnivores, percentages of energy from protein (13%), fat (37%), and carbohydrates (50%) as well as P/S ratio (0.63) were close to or within the range of Dutch guidelines regarding a healthy diet (percentages of energy from protein, fat, and carbohydrates 10-15, 30-35, and 55%, respectively: P/S ratio 0.5-1.0). For most of the micronutrients studied intake was adequate, and nutrient density of the vegetarian diet was higher than of the omnivorous diet. However, the supply of zinc (average daily intake 8.5 and 7.6 mg for men and women, respectively), iron (because of lower bioavailability of nonheme iron), vitamin B12 (women only: intake 2.3 micrograms/day), and water (daily intake less than 1600 ml for 30% of the vegetarians) need special attention, considering the relatively high prevalence of a marginal status of these nutrients. In conclusion, a lacto-(ovo-)vegetarian diet can be adequate at old age, provided that it is carefully planned, especially with respect to the supply of iron, zinc, and vitamin B12.     

Food iron absorption. I. Use of semisynthetic diet to study absorption of nonheme iron.

Recent studies have established the validity of employing an extrinsic radioiron tag to measure the absorption of nonheme iron from a complex meal. In the present study, extrinsic tagging was used to measure absorption of nonheme iron from a standard meal chosen as representative of a typical American meal, and from a semisynthetic meal having the same total chemical composition. The latter was designed so that the major dietary components could be systematically altered to determine their separate effects on food iron absorption. Absorption from the standard meal in 32 healthy women averaged 10.0% as compared with a mean absorption of 1.8% from semisynthetic meal. Most but not all of this fivefold difference in absorption could be explained by the enhancing effect of meat in the standard meal. The low availability of iron from the semisynthetic meal will be of particular value in studying factors which enhance food iron absorption, whereas the standard meal is suitable for studying factors which reduce availability of food iron.