Optimizing the functionality of clients with age-related macular degeneration.

Age-related macular degeneration (ARMD) is a major cause of severe vision loss and blindness among older people. This condition is progressive, incurable, and significantly compromises central vision. Rehabilitation nurses have a pivotal role in the assessment and management of clients with ARMD. An understanding of incidence and pathophysiology of ARMD, as well as health promotion and a new treatment for ARMD can help rehabilitation nurses design interventions to help clients maintain an acceptable quality of life despite declining vision.     

血清铁、铁蛋白和转铁蛋白与妊娠期糖尿病的相关性研究

目的探讨妊娠期糖尿病(GDM)与血清铁(SI)、血清铁蛋白(SF)和血清转铁蛋白(TRF)水平变化的关系及临床意义。方法选取2017年1-8月江苏省妇幼保健院孕周为24~28周的GDM孕妇121例作为GDM组,血糖正常的孕妇167例作为对照组。分别测定两组孕妇SI、SF、TRF、血红蛋白(Hb)、平均红细胞体积(MCV)、平均红细胞血红蛋白含量(MCH)、平均红细胞血红蛋白浓度(MCHC)水平并进行比较。结果与对照组孕妇比较,GDM组孕妇SI、SF、TRF水平均明显升高,差异均有统计学意义(P<0.05);两组孕妇Hb、MCV、MCH和MCHC水平比较,差异均无统计学意义(P>0.05);SI、SF及TRF水平与空腹血糖、1 h血糖、2 h血糖均呈正相关(P<0.05);单因素Logistic回归分析显示,当显著性水平α=0.05时,SI、SF和TRF水平均是GDM发病的危险因素(P<0.01)。结论孕妇体内铁储存水平的升高与GDM的发生密切相关。     

Serum ferritin, blood donation, iron stores and haemochromatosis

Summary. Serum iron and ferritin concentrations were measured in 1,532 regular blood donors from South Wales who were undergoing HLA typing prior to registration on the British Bone Marrow and Platelet Donor Panel. Serum transferrin concentrations were determined for donors with serum iron concentrations > 24 µmol/1. There were 25 donors with transferrin saturations > 50% and 11 with transferrin saturations > 60%. There were five donors with serum ferritin concentrations > 200 µg/1 (women) or > 300 µg/1 (men). Two of the male donors had transferrin saturations > 50% and serum ferritin >300 µg/1 on repeat blood samples and are being treated by venesection. Donors with HLA-A3 did not differ from those without A3 in serum iron or ferritin concentrations. Even in the group of donors who were apparently homozygous for A3 there were neither abnormal serum iron nor ferritin concentrations.
Although it is well established that measurements of transferrin saturation are required to detect homozygous haemochromatosis ( HFE ) in its earlier stages, the number of 'false-positive' results is likely to be unacceptably high for screening blood donors. Serum ferritin assays should identify donors with HFE and iron overload before the onset of liver damage. With two million regular donors and 300,000 new donors each year, a significant proportion of the U.K. population will be screened within 10 years. The assay of serum ferritin identifies donors with low levels of storage iron who are at risk of developing iron-deficiency anaemia. Furthermore, donation frequency may be increased for those donors with higher ferritin concentrations when blood supplies are low.     

Nutritional supplements in the prevention of age-related macular degeneration

The benefit of the AREDS study and of nutritional supplements in reducing the onset or progression of end-stage AMD in those known to be at risk is a step forward in our understanding of what can be a blinding and debilitating disease. Nutritional supplements are not without risks, and their effects must be diligently and accurately monitored. However, they pose a viable complement in the venue of treating ocular disease and conditions.     

Visual factors and mobility in persons with age-related macular degeneration

The objectives of this study were to determine the effects of reducing light level on mobility performance in persons with age-related macular degeneration (ARMD) and how performance relates to measures of visual sensory and perceptual function. ARMD results in the loss of central, high-acuity vision and is the leading cause of vision loss in veterans participating in the blind rehabilitation programs of the Department of Veterans Affairs. In 41 subjects with ARMD acuity, peak letter contrast sensitivity, visual field extent, glare disability, color confusion, spatio-temporal contrast sensitivity, motion sensitivity, scanning ability, and figure-ground discrimination were measured to determine their ability to predict mobility performance. Mobility performance was assessed under photopic (high illumination) and mesopic (low illumination) lighting conditions on a laboratory obstacle course and two real-world courses, an indoor hallway and an outdoor residential route. Reducing illumination resulted in significant increases in the time to complete each course and the number of mobility incidents (errors) that occurred. Two measures of overall performance, total time and total mobility incidents, were calculated for each course by summing time and incidents over the two illumination levels. Combinations of vision variables were able to account for 30 to 60% of the variance in the measures of overall performance. Log contrast sensitivity measured with the Pelli-Robson chart test and visual field extent were the most important predictors of performance. Other variables making significant contributions to prediction in multi-predictor models included: scanning ability, glare sensitivity, color confusion, and peak contrast sensitivity to drifting gratings.     

Recent developments in the treatment of age-related macular degeneration

Age-related macular degeneration (AMD) is a common cause of visual loss in the elderly, with increasing prevalence due to increasing life expectancy. While the introduction of anti-VEGF therapy has improved outcomes, there are still major unmet needs and gaps in the understanding of underlying biological processes. These include early, intermediate, and atrophic disease stages. Recent studies have assessed therapeutic approaches addressing various disease-associated pathways, including complement inhibitors. Drug-delivery aspects are also relevant, as many agents have to be administered repeatedly. Herein, relevant pathogenetic factors and underlying mechanisms as well as recent and potential therapeutic approaches are reviewed.     

Mucosal transferrin and ferritin factors in the regulation of iron absorption

1. A standardized decompensation and recompensation of iron homeostasis has been produced by a change-over from normal to iron deficiency and back. 2. Under these conditions the 59Fe uptake into transferrin and ferritin of the mucosal "cytosol" and SDS treated "membrane" fraction has been measured together with the 59Fe amount transferred into the body. 3. The increase of the intestinal 59Fe absorption due to a progressive iron deficiency is associated with an increase of the 59Fe uptake into the mucosal transferrin of the "cytosol" and the "membrane" fraction; the reverse is observed with regard to mucosal ferritin. 4. Three days after the re-establishment of normal conditions the 59Fe absorption was lowered to normal values, while the 59Fe uptake into mucosal ferritin achieved again normally high values. 5. The high apparent rate of absorption in iron deficient animals decreased during the last 50 min after injection of the 59Fe labelled test dose. The 59Fe content in the ferritin fraction increased simultaneously, whereas the 59Fe content in the transferrin fraction remained the same. 6. The conclusion is drawn that the intestinal iron absorption is regulated by both mucosal iron binding proteins. Mucosal transferrin is responsible for the increase of absorption in iron deficiency while mucosal ferritin is responsible for the inhibition of iron absorption when the iron homeostasis recompensats.     

Serum ferritin and iron stores during pregnancy

The iron status of two groups of pregnant women was investigated. One group did not receive iron (group B), the other erceived 100 mg iron/day (group A). 1. In all individuals concentrations of hemoglobin, serum iron, transferrin and serum ferritin were determined at regular intervals from the third month until delivery and at 3 months after delivery. The same determinations were performed in cord blood. 2. Changes in iron status appeared to be less in individuals with iron supplement than in those without iron supplement. A fall in Hb, serum iron and serum ferritin is observed in all individuals. 3. Three months after delivery the Hb concentration has generally returned to the normal female value, but the serum ferritin concentration is still very low. 4. The fetus does not discriminate as to the iron status of the mother. In both groups (A and B) cord blood values appeard to be not significantly different.     

补体因子H多态性在年龄相关性黄斑变性发病中的作用机制

目的:探讨补体H因子的多态性在年龄相关性黄斑变性疾病发生中的作用机制。资料来源:应用计算机检索PubMed数据库1983-01/2006-12相关年龄相关性黄斑变性及补体H因子多态性方面的文献,检索词"Age-related macular degeneration,complement factor H,polymorphism,epidemiology,etiology",限定文献语言种类为Engllish。资料选择:对资料进行初审,选取包括年龄相关性黄斑变性流行病学、病因学以及补体H因子多态性方面的文献,开始查找全文。纳入标准:文章所述内容与年龄相关性黄斑变性或补体H因子相关。排除标准:临床诊断及治疗。资料提炼:共检索到176篇相关文献,最终纳入38篇符合标准的文献。资料综合:年龄相关性黄斑变性的发病机制十分复杂,至今尚不清楚。最近研究发现,补体因子H在年龄相关性黄斑变性的发生、发展中起着相当重要的作用,如果补体因子H功能下降,补体被异常激活,导致补体成分C3b、C5b-9产生增多,C5b-9(膜攻击复合体)沉积于视网膜色素上皮细胞基底层,促进玻璃膜疣的形成并沉积于视网膜色素上皮层与Bruch膜之间,引起视网膜色素上皮层-Bruch膜-脉络膜毛细血管复合体变性,黄斑区和后极部萎缩,进而Bruch膜内胶原增厚,弹力纤维层断裂,脉络膜毛细血管进入视网膜色素上皮层下及视网膜神经上皮层下,最终导致视网膜下新生血管的形成,年龄相关性黄斑变性的发生。结论:补体因子H多态性在年龄相关性黄斑变性的发生中起着非常重要的作用,这为今后采取新的早期干预措施、寻求更为有效的治疗方法提供了新的方向。     

Ranibizumab: treatment in patients with neovascular age-related macular degeneration

Vascular endothelial growth factor (VEGF)-A is a major regulator of angiogenesis and vascular permeability implicated in the development of diseases involving pathological angiogenesis and increased vascular permeability, such as neovascular age-related macular degeneration (AMD). LUCENTIS (ranibizumab), a humanized antigen-binding fragment (Fab) that neutralizes all VEGF-A isoforms and their biologically active degradation products, was recently approved by the FDA. Ranibizumab is the first FDA-approved treatment for neovascular AMD that maintains or improves vision in > or = 90% patients and provides a > or = 15-letter improvement in visual acuity for a quarter to a third of patients with all choroidal neovascularisation subtypes. Ranibizumab was associated with a < or = 1.7% rate of key serious ocular adverse events, such as endophthalmitis and uveitis, in two pivotal Phase III trials.     

磁共振成像在年龄相关性黄斑变性中的研究进展

年龄相关性黄斑变性(age-related macular degeneration,AMD)好发于50岁及以上中老年人,呈进行性发展,可导致单眼或双眼部分乃至完全性视力丧失,是老年人视力丧失的主要原因.近年来,研究人员采用磁共振成像(magnetic resonance imaging,MRI)技术非侵入性地检查眼部...     

Ranibizumab: treatment in patients with neovascular age-related macular degeneration

Vascular endothelial growth factor (VEGF)-A is a major regulator of angiogenesis and vascular permeability implicated in the development of diseases involving pathological angiogenesis and increased vascular permeability, such as neovascular age-related macular degeneration (AMD). LUCENTIS? (ranibizumab), a humanised antigen-binding fragment (Fab) that neutralises all VEGF-A isoforms and their biologically active degradation products, was recently approved by the FDA. Ranibizumab is the first FDA-approved treatment for neovascular AMD that maintains or improves vision in ≥ 90% patients and provides a ≥ 15-letter improvement in visual acuity for a quarter to a third of patients with all choroidal neovascularisation subtypes. Ranibizumab was associated with a ≤ 1.7% rate of key serious ocular adverse events, such as endophthalmitis and uveitis, in two pivotal Phase III trials.     

Serum ferritin and iron status in 'healthy' elderly individuals

Iron status, including S-ferritin, S-iron, S-transferrin, transferrin saturation and haemoglobin, was assessed in 267 selected elderly subjects (128 male, 139 female) with a median age of 79 years (range 60-93 years) not suffering from diseases connected with inappropriately high S-ferritin. In both sexes, S-ferritin levels were practically constant over the examined age range. Males had a geometric mean ferritin of 75 micrograms/l and females a value of 60 micrograms/l (p less than 0.001). Levels of S-ferritin less than 15 micrograms/l (i.e. depleted iron stores) were found in 7.8% of males and in 10.1% of females. An S-ferritin level less than 15 micrograms/l and transferrin saturation less than 15% (i.e. latent iron deficiency) was observed in 2.3% of males and in 2.2% of females. None had iron deficiency anaemia. In subjects (n = 232) without iron deficiency [i.e. S-ferritin greater than or equal to 15 micrograms/l, mean red cell volume greater than or equal to 79 fl and haemoglobin greater than or equal to 121 g/l (7.5 mmol/l)], the arithmetic mean of S-iron was 18 mumol/l. S-transferrin 28 mumol/l and transferrin saturation 33%. The levels of S-iron, S-transferrin and transferrin saturation were not significantly different in males and females.     

Dried plasma spot measurements of ferritin and transferrin receptor for assessing iron status.

BACKGROUND: Efforts to reduce the high global prevalence of nutritional anemia require the use of both reliable laboratory assays to distinguish iron deficiency from other causes of anemia and cost-effective methods for collection of blood specimens under field conditions. The suitability of using small plasma samples spotted and dried on filter paper for measurements of plasma ferritin and transferrin receptor was evaluated in the present study. METHODS: Blood specimens obtained from 73 male and 83 female subjects (19-40 years) representing a wide range of iron status were used to perform parallel measurements of plasma ferritin and transferrin receptor on whole plasma and spotted plasma samples. RESULTS: Ratio plots, evaluating the acceptability and precision of the spot method in ferritin and transferrin receptor assays, showed the expected proportion of data points within the 95% prediction interval. In the composite group of 156 subjects, both the whole plasma and plasma spot methods gave a geometric mean transferrin receptor/ferritin ratio of 18. The regression equation for the ratio was logy = 1.045 logx - 0.05126; r = 0.986; P <0.0001. The ratio of transferrin receptor/ferritin determined from plasma spots correctly identified all 12 subjects with iron deficiency anemia compared with 11 of the 12 for whole plasma measurements. CONCLUSIONS: Measurements of ferritin and transferrin receptor on plasma spotted and dried on filter paper are comparable to whole plasma values for the identification of iron deficiency anemia. The use of dried plasma spots will facilitate the collection, storage, and transport of samples in epidemiological studies of anemia prevalence.     

Usefulness of soluble transferrin receptor and ferritin in iron deficiency and chronic disease

Soluble transferrin receptor (sTfR) is a biochemical parameter used for the detection of iron deficiency in situations where ferritin has limited diagnostic value owing to the present chronic disease. The sTfR concentration was determined in 118 patients divided according to their inflammatory status and underlying disease into groups of patients with iron‐deficiency anemia (IDA), anemia of chronic disease (ACD) and patients with a coexisting state of iron deficiency and anemia of chronic disease (ID+ACD). All patients with iron deficiency had elevated sTfR levels, but ferritin concentrations were normal or increased in patients with inflammatory characteristics. Diagnostic efficiencies of sTfR, sTfR/log ferritin index (sTfR/F) and ferritin were evaluated by receiver operating characteristic curve (ROC) analysis. According to the results obtained, the best diagnostic efficiency for differential diagnosis of anemic patients with iron deficiency compared to the control group had a sTfR concentration (0.884) that was significantly higher than ferritin (0.638), but not higher than the calculated ratio sTfR/F (0.820). The cut‐off value of the sTfR/F index differentiating the best control group from the IDA and ID+ACD groups was 1.30, and for differentiation of ACD from IDA and ID+ACD, the value was 0.90. Soluble transferrin receptor is an additional parameter to ferritin for the diagnosis of IDA and differential diagnosis of ID+ACD, but calculation of the sTfR/F index did not improve the diagnostic value of determining sTfR alone.     

Usefulness of soluble transferrin receptor and ferritin in iron deficiency and chronic disease

Soluble transferrin receptor (sTfR) is a biochemical parameter used for the detection of iron deficiency in situations where ferritin has limited diagnostic value owing to the present chronic disease. The sTfR concentration was determined in 118 patients divided according to their inflammatory status and underlying disease into groups of patients with iron-deficiency anemia (IDA), anemia of chronic disease (ACD) and patients with a coexisting state of iron deficiency and anemia of chronic disease (ID+ACD). All patients with iron deficiency had elevated sTfR levels, but ferritin concentrations were normal or increased in patients with inflammatory characteristics. Diagnostic efficiencies of sTfR, sTfR/log ferritin index (sTfR/F) and ferritin were evaluated by receiver operating characteristic curve (ROC) analysis. According to the results obtained, the best diagnostic efficiency for differential diagnosis of anemic patients with iron deficiency compared to the control group had a sTfR concentration (0.884) that was significantly higher than ferritin (0.638), but not higher than the calculated ratio sTfR/F (0.820). The cut-off value of the sTfR/F index differentiating the best control group from the IDA and ID+ACD groups was 1.30, and for differentiation of ACD from IDA and ID+ACD, the value was 0.90. Soluble transferrin receptor is an additional parameter to ferritin for the diagnosis of IDA and differential diagnosis of ID+ACD, but calculation of the sTfR/F index did not improve the diagnostic value of determining sTfR alone.