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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Certain analyses have suggested that the United States has lower patient survival than other comparable industrialized nations, but it remains to be determined whether this is due to the "adequacy" of dialysis in the United States. Substantial evidence exists that the doses of hemodialysis delivered in the United States have increased over the last 6 years. Databases from Fresenius Medical Care and the National Core Indicators Project from the Health Care Financing Administration (HCFA) have shown that as dialysis dose has increased, mortality has decreased. However, commensurate with this has been the introduction of other technologies and practices, such as anemia control and others. Discerning the relative role of these independent factors on outcome remains complicated. While awaiting the results of the National Institutes of Health HEMO study, this article discusses the merits and contributions of the increasing doses of dialysis on outcome.
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PMID:Status of hemodialysis adequacy in the United States: does it account for improved patient survival? 989 72

X-linked sideroblastic anemia and ataxia (XLSA/A) is a recessive disorder characterized by an infantile to early childhood onset of non-progressive cerebellar ataxia and mild anemia with hypochromia and microcytosis. A gene encoding an ATP-binding cassette (ABC) transporter was mapped to Xq13, a region previously shown by linkage analysis to harbor the XLSA/A gene. This gene, ABC7, is an ortholog of the yeast ATM1 gene whose product localizes to the mitochondrial inner membrane and is involved in iron homeostasis. The full-length ABC7 cDNA was cloned and the entire coding region screened for mutations in a kindred in which five male members manifested XLSA/A. An I400M variant was identified in a predicted transmembrane segment of the ABC7 gene in patients with XLSA/A. The mutation was shown to segregate with the disease in the family and was not detected in at least 600 chromosomes of general population controls. Introduction of the corresponding mutation into the Saccharomyces cerevisiae ATM1 gene resulted in a partial loss of function of the yeast Atm1 protein. In addition, the human wild-type ABC7 protein was able to complement ATM1 deletion in yeast. These data indicate that ABC7 is the causal gene of XLSA/A and that XLSA/A is a mitochondrial disease caused by a mutation in the nuclear genome.
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PMID:Mutation of a putative mitochondrial iron transporter gene (ABC7) in X-linked sideroblastic anemia and ataxia (XLSA/A). 1019 63

In the recent HEMO study, the most common cause of death in dialyzed patients was ischemic heart disease. In Europe there are regional differences, but the mortality due to cardiovascular disease is also very high. The long-lasting controversy whether the high incidence and prevalence of atherosclerotic manifestations (particularly ischemic heart disease) may be explained by known risk factors, or non-traditional risk factors are also involved seems to be partially solved with the increasing evidence that the latter hypothesis is true. Thus, together with classic risk factors such as hypertension, dyslipidemia and diabetes, other situations such as microinflammation, increased concentration of asymmetrical dimethyl-L-arginine, disturbed phosphate metabolism and anemia may represent important risk factors for accelerated atherosclerosis in dialyzed patients.
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PMID:Atherosclerosis in dialyzed patients. 1473 9

The main problem nephrologists have to face today is the very high patient morbidity and mortality. A number of traditional and non-traditional risk factors have a role; among these anaemia, hypertension, dislipidemia, abnormalities in calcium-phosphate metabolism, hyperhomocysteinemia and endothelial dysfunction. An important innovation in the field of hemodialysis has been the availability of high-permeable and high-flux membranes, characterized by a high biocompatibility and ultrafiltration coefficient. The development of automatic systems to control ultrafiltration has enabled the utilisation of these membranes in the clinical setting (high-flux hemodialysis, hemofiltration, hemodiafiltration). It is common opinion that high-flux membranes can positively influence cardiovascular instability, but this has not been confirmed by clinical trials. Although preliminary data indicated a favorable effect on the correction of anemia in patients treated with high-permeable membranes, randomized trials have not shown a significant effect. Better control of anemia could be possible by means of on-line treatments, given their higher removal of medium- and large molecules and reduced microbiological and pyrogenic contamination of the dialysate. A number of analyses showed a lower incidence of bone cysts and/or carpal tunnel syndrome in patients treated with high-flux membranes compared to low-flux ones. High-flux treatments could reduce morbidity and mortality in hemodialysis patients. However, despite its large sample size, the HEMO Study has not been capable of showing a statistically significant effect of higher dialysis dose and high-flux membranes on survival and morbidity. The MPO study has been expressively designed to do a prospective evaluation of the long-term effect of membrane permeability on clinical outcomes. These results are greatly awaited.
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PMID:[Clinical dialysis: new problems and new prospects]. 1535 50

Despite several technical advances in dialysis treatment modalities and a better patient care management including correction of anemia, suppression of secondary hyperparathyroidism, lipid and oxidative stress profiles improvement, the morbidity and the mortality of dialysis patients still remain still elevated. Recent prospective interventional trials in hemodialysis (HEMO study and 4D study) were not very conclusive in showing any significant improvement in dialysis patient outcomes. High-efficiency convective therapies, such as online hemodiafiltration (HDF), are claimed to be superior to conventional diffusive hemodialysis (HD) in improving the dialysis efficacy and in reducing intradialytic morbidity and all-cause and cardiovascular mortality in dialysis patients. The aim of this report was, first, to review the evidence-based facts tending to prove the superiority of HDF vs. HD in terms of efficacy and tolerance, and, second, to analyze the needs to prove the clinical superiority of HDF in terms of reducing morbidity and all-cause mortality of dialysis patients. A systematic review of studies comparing HDF and HD has been performed in the microbiological safety of online production, the solute removal capacity of small and medium-size uremic toxins, and its implication in the reduction of the bioactive dialysis system vs. patient interaction. Major planned randomized international studies comparing HDF and HD in terms of morbidity and mortality have been reviewed. To conclude, it is thought that these long-term prospective randomized trials will clarify on a scientific evidence-based level the putative beneficial role of high-efficiency HDF modalities on dialysis patient outcomes.
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PMID:Overview of clinical studies in hemodiafiltration: what do we need now ? 1644 70

The need to improve the dialysis outcomes, the negative results from the HEMO and ADEMEX studies as well reports of clinical benefits have rekindled the interest in daily hemodialysis. Although no randomized controlled studies have been published, a large number of manuscripts have described significant benefits from both the short or nocturnal forms of daily (quotidian) dialysis or hemo(dia)filtration. They include improved quality of life, hemodynamic stability, blood pressure control with minimal number of medications, anemia control, regression of cardiac hypertrophy and improved nutrition. Furthermore, quotidian nocturnal hemodialysis provides higher dialysis dose, and has been described to improve endothelial as well as endothelial progenitor cell function, heart rate variability, sleep and phosphate control while it offers unrestricted diet. Several studies have pointed to a lower overall cost and improved cost utility when treating patients using quotidian hemodialysis at home. The obstacles to widespread use are the reimbursement structure in most countries, the willingness and ability of the patients to do home hemodialysis and the availability of user-friendly machines. A prospective randomized controlled study sponsored by the National Institutes of Health (NIH) and US Centers for Medicare and Medicaid services (CMS) currently underway will be pivotal in confirming these benefits and convincing the stakeholders to promote the use of daily hemodialysis.
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PMID:Daily hemodialysis 2006. State of the art. 1676 65

X-linked sideroblastic anemia with ataxia (XLSA/A) is caused by defects of the transporter ABCB7 and is characterized by mitochondrial iron deposition and excess of protoporphyrin in erythroid cells. We describe ABCB7 silencing in HeLa cells by performing sequential transfections with siRNAs. The phenotype of the ABCB7-deficient cells was characterized by a strong reduction in proliferation rate that was not rescued by iron supplementation, by evident signs of iron deficiency, and by a large approximately 6-fold increase of iron accumulation in the mitochondria that was poorly available to mitochondrial ferritin. The cells showed an increase of protoporphyrin IX, a higher sensitivity to H(2)O(2) toxicity, and a reduced activity of mitochondrial superoxide dismutase 2 (SOD2), while the activity of mitochondrial enzymes, such as citrate synthase or succinate dehydrogenase, and ATP content were not decreased. In contrast, aconitase activity, particularly that of the cytosolic, IRP1 form, was reduced. The results support the hypothesis that ABCB7 is involved in the transfer of iron from mitochondria to cytosol, and in the maturation of cytosolic Fe/S enzymes. In addition, the results indicate that anemia in XLSA/A is caused by the accumulation of iron in a form that is not readily usable for heme synthesis.
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PMID:RNA silencing of the mitochondrial ABCB7 transporter in HeLa cells causes an iron-deficient phenotype with mitochondrial iron overload. 1719 93

The interest of investigators in intensified dialysis regimens has been growing in recent years, especially since the HEMO Study Group showed that a higher dose of thrice-weekly hemodialysis fails to reduce mortality and morbidity but improves clinical outcomes. Alternative hemodialysis strategies including short daily hemodialysis (SDHD), long hemodialysis (LHD) and nocturnal daily hemodialysis (NDHD) have been developed in the hope to improve patients' outcomes. A growing number of investigators are studying patients on alternative dialysis regimens and most publications in this field have reported significant improvements in clinical outcomes including left ventricular hypertrophy, blood pressure control, anemia, calcium-phosphate metabolism, and fluid and electrolyte balance; all of these parameters can be considered as indirect signs of improvement in quality of life. However, the strength of these results is often limited by shortcomings in study design. Indeed, in most of these studies an adequate control group is missing, the patient groups are not properly matched, and the number of patients enrolled is small. Similarly, most studies have evaluated the effects of NDHD and/or nocturnal LHD on health-related quality of life (HRQoL) by questionnaire administration. Even though better results might be achieved with nocturnal hemodialysis, no conclusive data exist to prove statistically significant differences in HRQoL between conventional and intensive hemodialysis. In conclusion, all of these novel dialysis strategies offer reliable opportunities for uremic patients, but further trials are needed to determine whether alternative hemodialysis can reduce morbidity and mortality in this high-risk population of patients.
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PMID:[Nocturnal hemodialysis: an alternative treatment for a better quality of life]. 1904 71

X-linked sideroblastic anemia with ataxia (XLSA/A) is a rare inherited disorder characterized by mild anemia and ataxia. XLSA/A is caused by mutations in the ABCB7 gene, which encodes a member of the ATP-binding cassette transporter family. Studies in yeast, mammalian cells, and mice have shown that ABCB7 functions in the transport of iron-sulfur (Fe-S) clusters into the cytoplasm. To further investigate the mechanism of this disease, we have identified and characterized the Caenorhabditis elegans homologue of the ABCB7 gene, abtm-1. We have studied the function of abtm-1 using mutants and RNAi. abtm-1-depleted animals produce arrested embryos that have morphogenetic defects and unusual premature, putative apoptotic events. abtm-1(RNAi) animals also show accumulation of ferric iron and increased oxidative stress. Despite the increased level of oxidative stress in abtm-1(RNAi) animals, they have an increased life span. We observed accumulation of DAF-16/FOXO in the nuclei of affected animals and elevation of the expression of SOD-3, a well established target of DAF-16, which may explain the increased life span extension of these animals. abtm-1 is strongly expressed in tissues with a high energy demand, and abtm-1(RNAi) animals have phenotypes that reflect the need for abtm-1 in these tissues. Finally, we show that reducing the function of other genes involved in Fe-S cluster production produces similar phenotypic consequences to abtm-1 loss of function. Therefore, ablation of abtm-1 in C. elegans provides a model in which to investigate the mechanism underlying XLSA/A.
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PMID:Disruption of the ATP-binding cassette B7 (ABTM-1/ABCB7) induces oxidative stress and premature cell death in Caenorhabditis elegans. 2146 30

X-linked sideroblastic anemia and ataxia (XLSA-A) is a rare cause of early onset ataxia, which may be overlooked due to the usually mild asymptomatic anemia. The genetic defect has been identified as a mutation in the ABCB7 gene at Xq12-q13. The gene encodes a mitochondrial ATP-binding cassette (ABC) transporter protein involved in iron homeostasis. Until now only three families have been reported, each with a distinct missense mutation in this gene. We describe a fourth family with XLSA-A and a novel mutation in the ABCB7 gene.
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PMID:X-linked sideroblastic anemia and ataxia: a new family with identification of a fourth ABCB7 gene mutation. 2239 76


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