The Significance of Iron Turnover in the Control of Iron Absorption

Following acute blood loss, there is a 4- to 5-day lag before any demonstrable change in plasma iron kinetics. Then there is a shortened Fe⁵⁹T and transient fall in the plasma iron. Associated with this is a decreasein the intestinal content of iron and an increased absorption of iron. We suggest the iron content of the epithelial cell is important in the regulation ofits ability to absorb iron. The intestinal iron content is in turn closely controlled by the plasma iron turnover.

Submitted on October 7, 1963 Accepted on December 3, 1963     

The Effect of Injected Iron on the Absorption of Iron in Iron Deficiency

S ummary . The effects of injected iron on the absorption of iron by iron deficient animals have been studied. When iron deficiency is partly or fully corrected by injection of iron dextran, prolonged and marked depression of iron absorption follows despite the persistence of iron deficiency. Although total absorption increases with decreasing size of parenteral replacement dose, the depression of absorption per unit of iron injected increases.     

铁离子在脑出血中的损伤机制及铁螯合剂的神经保护作用

脑出血后脑组织发生一系列病理生理学变化,主要包括血肿扩大、血肿周围代谢异常以及脑水肿形成。近年来的研究表明,铁离子在脑出血后继发性脑损伤中起重要作用,铁螯合剂能够特异性结合铁离子并阻断其介导的损伤过程。文章就脑出血后铁离子的代谢变化、铁离子相关性脑损伤机制以及铁螯合剂的神经保护作用进行综述。     

抵抗素基因-420C>G位点多态性对脑出血患者血浆抵抗素水平的影响

目的探讨抵抗素基因-420C>G位点单核苷酸多态性对脑出血患者血浆抵抗素水平的影响。方法选取344例高血压性基底核出血患者,入院时抽取外周血提取DNA,采用聚合酶反应-限制性片断多态性分析基因型,同时采用ELISA法检测血浆抵抗素浓度,进行统计分析。结果酶切后可见抵抗素基因-420C>G位点有CC、CG和GG三种基因型,等位基因C和G的频率分别为71.08%和28.92%,基因型CC、CG和GG的频率依次为50.29%、41.57%和8.14%。经Hardy-Weinberg遗传平衡定律检验,各基因型频率符合遗传平衡。CC、CG和GG基因型患者血浆抵抗素浓度依次为(23.83±7.09)ng/mL、(26.54±7.32)ng/mL和(27.18±9.97)ng/mL。CC基因型患者血浆抵抗素均显著低于CG和GG基因型患者(P<0.01,P<0.05)。结论抵抗素基因-420C>G位点单核苷酸多态性显著影响脑出血患者血浆抵抗素水平,可能参与脑出血炎症反应。     

蛛网膜下腔出血后铁代谢机制的研究进展

脑血管痉挛(CVS)是蛛网膜下腔出血(SAH)的常见并发症,是SAH患者致死、致残的主要原因之一.近年来对其发病机制及治疗方法进行了深入的研究,发现铁代谢在SAH后脑血管痉挛中有着重要作用.本文就近年来国内外学者在SAH后铁代谢病理生理机制的研究进展作一综述.     

The Relationship between Marrow Iron Stores,Plasma Ferritin Concentrations and Iron Absorption

The percentage absorption from a 3 mg dose of ferrous iron was measured in 50 subjects with iron stores that varied over a wide range. Iron status was assessed by a number of measurements, including the haemoglobin concentration, the plasma iron concentration, the total iron-binding capacity, the plasma ferritin concentration and the concentration of non-haem iron in the bone marrow. There were good inverse correlations between the log percentage iron absorption and both the log marrow non-haem iron concentration (r —0.94; P < 0.001) and the log plasma ferritin concentration (r —0.78; P < 0.001). In addition, there was a positive correlation between the marrow non-haem iron concentration and the plasma ferritin concentration (r +0.84; P <0.001). These results suggest that reticuloendothelial iron stores represent an important determinant of iron absorption and that their size can be guaged from the plasma ferritin concentration.     

尼莫地平治疗蛛网膜下腔出血的疗效观察

目的观察尼莫地平治疗蛛网膜下腔出血的疗效。方法选择2010年11月—2012年11月在我院住院的蛛网膜下腔出血患者68例,将其随机分为对照组和治疗组,各34例。对照组给予常规治疗,治疗组在此基础上给予尼莫地平持续泵注治疗,比较两组治疗效果。结果治疗组总有效率为94.1%(32/34),高于对照组的52.9%(18/34)(P0.05);治疗组脑血管痉挛发生率、病死率及复发率均低于对照组(P0.05);两组均无明显不良反应。结论尼莫地平能显著提高蛛网膜下腔出血患者的疗效,降低脑血管痉挛的发生率及病死率,不增加再出血风险。     

The Relationship between the Turnover Rate of Neutrophilic Granulocytes and. Plasma Lysozyme Levels

S ummary . Thirty-six kinetic studies with radioactive diisopropylfluoro-phosphate (DF³²P) labelled neutrophilic granulocytes were carried out in 33 patients with a wide range of neutrophil counts, and the kinetic data compared with plasma lysozyme levels. A highly significant correlation was found between the neutrophil turnover rate and plasma lysozyme, which suggests that plasma lysozyme is mainly derived from disintegrating neutrophilic granulocytes. Recovery calculations showed, however, that in patients with normal and increased neutrophil counts at least 40% of the neutrophils passing through the blood did not deliver their lysozyme content back to the plasma, probably due to either lysozyme degradation in the tissues and/or due to loss of intact neutrophils from the organism, e.g. to the alimentary tract. The high degree of correlation between the neutrophil turnover rate and plasma lysozyme levels makes it possible, with certain provisos, to use plasma lysozyme levels in the clinical assessment of the neutrophil turnover rate.     

The Effect of Food Consistency on Iron Absorption

Iron absorption and the half-time of gastric emptying were measured concurrently in 13 normal volunteer subjects. Each subject ate two test meals of identical composition; one meal was prepared and served in the usual manner while the second was homogenized before serving. No correlation was found between the half-time of gastric emptying and the absorption of either heme or nonheme iron among subjects eating the conventional meal. Homogenization of the meal led to a 31% fall in the mean half-time of gastric emptying and an increase in iron absorption of 22% for nonheme and 42% for heme. These findings indicate that the physical form of a meal has a modest effect on iron absorption.     

The Effect of Transferrin Polymorphisms on Iron Metabolism

ABSTRACT: The effect of five different transferrin variants (TFv1, TFv2, TFv3, TFv4, and TFv5) on the hemoglobin level, mean corpuscular volume (MCV), ferritin level, percent transferrin saturation (%TS), and the unsaturated iron binding capacity (UIBC) was investigated in subjects with defined HFE haplotypes, 919 persons undergoing health screening and 113 patients with clinical hemochromatosis. The most common variant is TFv4; the population distribution of this variant was also studied. None of the variants were found to have an effect on any of the parameters of iron metabolism that were investigated. Moreover, the frequency of these variants in patients with clinically significant hemochromatosis was no different from that in the general population. We conclude that these polymorphisms in transferrin do not play a role in the expression of hemochromatosis, nor do they produce any other significant changes in iron metabolism.     

Effect of Chronic Ethanol Exposure on Myocardial Phosphoinositide Turnover

The effect of chronic ethanol consumption (2 months) on atrial contractility and the myocardial phosphoinositide signaling system was examined in rat heart. Two months of ethanol consumption was not associated with changes in heart weight-to-body weight ratios; however, developed twitch tension was significantly lower in the ethanol atria compared with the control atria. Cytosolic and membrane-associated phospholipase C activity in atrial and ventricular tissue was measured and ethanol consumption was only associated with changes in ventricular cytosolic phospholipase C activity. When examining α₁-adrenergic stimulated phosphoinositide turnover in [³H]inositol radiolabeled left atria, no differences in phenylephrine (10 μM)-stimulated inositol monophosphate, inositol bisphosphate, inositol trisphosphate, and inositol tetrakisphosphate were found between groups before or at various times after the addition of phenylephrine. It is concluded that short-term ethanol consumption is associated with depressed contractile function, but not the development of hypertrophy or changes in α₁-adrenoreceptor-stimulated phosphoinositide turnover.     

The Relationship between Body Iron Stores and Ferritin Turnover in Rat Liver and Intestinal Mucosa

A single dose of oral or parenteral iron is known to stimulate ferritin synthesis in the liver and small intestine in experimental animals. A study has been carried out on the ferritin content and ferritin turnover in rat liver and intestinal mucosa in iron deficient, normal and iron loaded animals. [I-¹⁴C]DL-leucine incorporation into ferritin was used as a measure of its synthesis.
A significantly greater ferritin accumulation was found in the intestinal mucosa of the group of iron loaded animals compared with normal or iron deficient rats ( P < 0.001). In the liver the ferritin protein, ferritin iron and labelled ferritin content was significantly different between all three groups ( P < 0.001), the amounts being higher in the iron loaded animals and lower in the iron deficient animals when compared with the normal group. These results may explain how the absorption of iron in the small intestine is controlled by body iron stores.     

The Effect of Iron Stores on Ferrokinetics in Polycythaemia

The ferrokinetic data of patients with primary polycythaemia are those of patients with depleted iron stores. Differences in iron kinetics between polycythaemia vera and secondary polycythaemia are related to the variation in the quantity of iron stores and do not appear to be inherent to the type of polycythaemia. If ferrokinetic studies are to be used to evaluate or classify polycythaemia, storage iron must be assessed.     

血浆瘦素水平与脑出血预后的相关性分析

目的探讨脑出血患者血浆瘦素水平及其对脑出血预后的预测价值。方法收集高血压性基底节区出血患者为脑出血组共108例,同期健康体检人群为对照组共50例,采用ELISA法检测两组血浆瘦素水平,分析其与脑出血后3个月死亡的相关性。结果脑出血组血浆瘦素水平[(33.24±15.25)ng/ml]与对照组[(10.31±4.93)ng/ml]比较差异有统计学意义(P<0.01)。多因素分析显示,血浆瘦素水平是脑出血后3个月内死亡的独立危险因素(OR=1.31,95%CI=1.08~2.26,P<0.05)。ROC曲线分析显示,血浆瘦素水平对脑出血后3个月内死亡有显著预测价值(曲线下面积=0.86,95%CI=0.78~0.92,P<0.01),且判定血浆瘦素水平大于41.73ng/ml,对预测脑出血后3个月内死亡的灵敏度为71.43%和特异度为87.50%。结论脑出血后血浆瘦素水平升高,检测血浆瘦素水平有助于早期判断脑出血患者的死亡。     

去铁敏治疗大鼠脑出血后脑水肿的疗效观察

目的探讨铁螯合剂———去铁敏不同时间点治疗大鼠脑出血后脑水肿的效果。方法大鼠脑出血建模后,随机分组,并设立对照组,观察每组动物给药前后的神经功能缺损症状及其脑组织的水含量、钠离子含量和铁离子含量的变化。结果脑出血大鼠在不同时间点给予去铁敏治疗均能明显改善大鼠的神经功能缺损症状,且较对照组有显著性差异(P<0.01);同时也能明显降低血肿周围脑组织水和Na+含量。术后24h给予去铁敏治疗对脑组织铁离子含量无明显影响(P>0.05);术后72h小时去铁敏治疗则明显降低脑组织铁离子的含量(P<0.01)。结论去铁敏对大鼠脑出血后脑水肿的治疗有一定效果。     

Turnover of Ethyl-Linoleate in Rat Plasma and Its Distribution in Various Organs

The fate of [¹⁴C]ethyl-linoleate (EthLin) after its intravenous administration was investigated in pentobarbital-anesthetized rats. The disappearance of [¹⁴C]EthLin from the plasma was very rapid and followed quite closely a biexponential function of time. Fitting of the experimental data to a two-compartmental mammillary model revealed that the labeled compounds are eliminated from the plasma with a half-life of <1 min during the early time following the intravenous injection and that a large portion of the EthLin is hydrolyzed instantly to linoleic acid and ethanol. About 9–11 % of the plasma [¹⁴C]EthLin or its breakdown products are irreversibly cleared from the plasma compartment each minute. Most of the ¹⁴C-labeled compounds that originated in the plasma were recovered in the rat liver and lungs and to a lesser extent in the heart, spleen, and kidneys. Two hr after the [¹⁴C]EthLin administration, -2.5–5.5% of the total radioactivity in the various organs was still associated with EthLin. Such accumulations, although relatively small, indicate that fatty acid ethyl esters (FAEEs) may be taken up from the plasma. Thus, some of the FAEEs that are formed in certain organs may spillover to the circulating blood where much of it would be hydrolyzed to free fatty acids, but reuptake from the plasma may still account, to some extent, to FAEE-induced damage in chronic alcohol abusers.     

The Effect of Neomycin on Iron Absorption in Germfree Rats

Studies of radioiron absorption were performed on two groups of adult male germfree and open animal room rats which had been raised under special conditions. The latter were housed in germfree type isolators and shielded from further external bacterial exposure from weanling to adult life. Both groups were given a 5 day course of neomycin treatment and 1 day later radioiron was administered by intragastric instillation. Both groups showed an increase in radioiron absorption and total serum iron level over controls at death 7 days following intragastric instillation. Our findings suggest that the neomycin effect on iron absorption is a complex one which may operate in the absence of living bacteria.     

Plasma Iron and Erythrocytic Glutathione Peroxidase Activity

The red cell glutathione-peroxidase (GSH-Px) activity of 9 normal subjects is compared with that of 15 cases of iron deficiency anaemia and with 13 cases of heterozygous beta-thalassaemia with the same degree of anaemia and hypochromia. 2 cases of sideroblastic anaemia with high serum iron levels were also examined. Enzymatic activity was found to be significantly decreased in iron deficiency anaemia (about 55 % of normal range), while it was not affected in heterozygous betathalassaemia and it was increased in the 2 cases of sideroblastic anaemia. Moreover, GSH-Px activity exhibited a significant correlation with serum iron levels in all the patients studied. The observed modifications in GSH-Px activity are not correlated with erythrocyte ageing because reticulocyte-poor fractions exhibited GSH-Px activity which was not significantly reduced in respect of the reticulocyte-rich ones. These data seem to suggest that iron has a crucial connection with erythrocyte GSH-Px and that the enzyme deficiency may be of some importance in explaining the decreased red cell survival observed in severe iron-deficiency anaemias.     

The Effect of Acetaldehyde on Human Plasma Factor XIII Function

The effect of acetaldehyde on the transglutaminase activity in pooled normal human plasma has been investigated. In this study, 0.05, 0.2, and 0.7 ml of pooled human plasma were preincubated for 30 min. at room temperature with buffer or acetaldehyde at final concentrations of 40.6, 22.4, and 11.2 mM before being utilized for Factor XIIIa assay with fibrinogen and thrombin which had been preheated at 40°C to destroy endogenous Factor XIII/XIIIa activity. At all concentrations of acetaldehyde and all concentrations of plasma-containing Factor XIII which were employed, prolongation of both clotting time and stabilization time was observed. The 11.2 mM acetaldehyde is within the range of daily acetaldehyde production to be predicted in severe alcoholics as a consequence of imbibing alcohol. The stabilization times measured for Factor XIIIa activity appear to be the most sensitive to acetaldehyde compared to acetaldehyde effects on thrombin, Factor Xa, and fibrinogen studied earlier in this laboratory, as well as Factors II, VII, and X.