Optimization of the Urea Removal in a Wearable Dialysis Device Using Nitrogen-Doped and Phosphorus-Doped Graphene.

Dialysis has been recognized as an essential treatment for end-stage renal disease (ESRD). This therapy, however, suffers from several limitations leading to numerous complications in the patients. As dialysis cannot completely substitute healthy kidney functions, the health condition of an ESRD patient is ultimately affected. Wearable artificial kidney (WAK) can resolve the restrictions of blood purification by the dialysis method. However, absorbing large amounts of urea produced in the body is one of the main challenges of these WAK and overcoming this is necessary to improve both functionality and footprint of the device. This study investigates the adsorption capabilities of N- and P-doped graphene nanosorbents for the first time by using molecular dynamic simulation. Urea removal on carbon nanosheets was simulated with different percentages of phosphorus and nitrogen dopants along with the pristine graphene. Specifically, the effects of interaction energy, adsorption percentage, gyration radius, hydrogen bonding, and other molecular dynamic analyses on urea removal were also investigated. The results from this study match well with the existing research, demonstrating the accuracy of the model. The results further suggest that graphene nanosheets doped by 10% nitrogen are likely the most effective in removing urea given that it is associated with the maximum radial distribution function (RDF), the maximum reduction in gyration radius, a high number of hydrogen bonds, and the most negative adsorption energy. This molecular study offers attractive suggestions for the novel adsorbents of artificial kidney devices and paves the way for the development of novel and enhanced urea adsorbents.

Heterozygosity for the Novel HBA2: c.*91_*92delTA Polyadenylation Site Variant on the α2-Globin Gene Expanding the Genetic Spectrum of α-Thalassemia in Iran.

There are four copy numbers of α-globin genes (16p13.3) in the human genome and the number of defective α-globin genes dictates the severity of α-thalassemia (α-thal). Mutations that occur in the 3' untranslated region (3'UTR), and especially at the polyadenylation (polyA) sites, affect the translation, stability and export of mRNA. A patient with hypochromic microcytic anemia was referred to the Kariminejad-Najmabadi Pathology & Genetics Center, Tehran, Iran by the health network. Molecular analysis of genomic DNA for the evaluation of mutations on the α- and ß-globin genes was performed. Direct sequencing of the hemoglobin (Hb) subunit α2 (HBA2) gene revealed a two nucleotide deletion between +816 and +817 in the 3'UTR, located at the polyA site, which seems to be a novel pathogenic variant. This novel variant expands the genetic spectrum of α-thal in the 3'UTR of the HBA2 gene.

Frequency of α-Globin Gene Triplications and Coinheritance with ß-Globin Gene Mutations in the Iranian Population.

Numerical variation in α-globin genes is very important due to their roles as an effective factor for phenotype presentation. An unequal crossover from misalignment of a homologous sequence of an α-globin gene during meiosis can produce a numerical alteration. A single α-globin gene deletion is the most frequent mutation in α-thalassemia (α-thal) worldwide, while the additional α-globin chain is relatively common. The excess α-globin gene plays a critical role in pathophysiology of thalassemia, especially when in coinherited with ß-thalassemia (ß-thal). α-Globin triplication leads to an imbalanced ratio between α- and ß-globin chains, thus, it can exacerbate the clinical and hematological features of ß-thal. Different studies have been performed in various countries to determine the frequency of α-globin triplication and its genotype-phenotype correlation with ß-thal. In this study, we focused on the frequency of α-globin gene triplication and its characterization, either solely or in coexistence with ß-globin gene mutations in Iranian populations. We have investigated the α-globin gene rearrangements in 4010 individuals from different provinces of Iran with normal to abnormal hematological parameters. In total, the frequency of the αααanti 3.7 triplication was 1.7% and phenotype aggravation was observed in α-globin triplication patients who were carriers of ß-thal. Therefore, identification of genotype-phenotype correlation of α-globin triplication with ß-thal can be very useful for predicting the severity of clinical manifestations during genetic counseling.

Outcomes by day and night for patients bypassing the emergency department presenting with ST-segment elevation myocardial infarction identified with a pre-hospital electrocardiogram.

BACKGROUND: Pre-hospital ECG and emergency department (ED) bypass direct to the catheter laboratory may optimize reperfusion times for patients with ST-segment elevation myocardial infarction. Questions remain over feasibility and safety during off hours. AIMS: To determine if presenting time of day is associated with differences in in-hospital and 30-day mortality and key reperfusion times. METHODS/RESULTS: Seven hundred and twenty consecutive patients with STEMI triaged directly from the field to the catheter laboratory between June 2004-May 2013. Vital status was reported as of August 2013. The mean age was 65 ± 14 years, and 75.1% were male. Overall mortality (in-hospital/30 days) did not significantly differ for patients (3.4% in hours and 3.1% off hours; P = N/S). Symptom onset-to-arrival to the heart attack was non-significantly lower (100 minutes off hours (IQR 78-174) versus 110 minutes in hours (IQR 75-199), P = N/S). Call-to-balloon time was not significantly affected by the time of presentation: 150 min in hours (IQR 111-239) versus 154 minutes during off hours (IQR 115-225) P = N/S. Overall door-to-balloon time was 36 minutes (IQR 25-51), 34 minutes in hours (IQR 24-49) versus 40 minutes off hours (IQR 29-55) P = N/S. The overall false positive activation rate was only 13.1%, (in hours 12.2% vs. off hours 14.6%, respectively, P = N/S). CONCLUSIONS: In a unit with an established field triage system facilitating ED bypass, reperfusion times and mortality are not significantly influenced by whether the patient presents during standard working hours or outside of these hours.

Extracellular allosteric Na(+) binding to the Na(+),K(+)-ATPase in cardiac myocytes.

Whole-cell patch-clamp measurements of the current, Ip, produced by the Na(+),K(+)-ATPase across the plasma membrane of rabbit cardiac myocytes show an increase in Ip over the extracellular Na(+) concentration range 0-50 mM. This is not predicted by the classical Albers-Post scheme of the Na(+),K(+)-ATPase mechanism, where extracellular Na(+) should act as a competitive inhibitor of extracellular K(+) binding, which is necessary for the stimulation of enzyme dephosphorylation and the pumping of K(+) ions into the cytoplasm. The increase in Ip is consistent with Na(+) binding to an extracellular allosteric site, independent of the ion transport sites, and an increase in turnover via an acceleration of the rate-determining release of K(+) to the cytoplasm, E2(K(+))2 → E1 + 2K(+). At normal physiological concentrations of extracellular Na(+) of 140 mM, it is to be expected that binding of Na(+) to the allosteric site would be nearly saturated. Its purpose would seem to be simply to optimize the enzyme's ion pumping rate under its normal physiological conditions. Based on published crystal structures, a possible location of the allosteric site is within a cleft between the α- and ß-subunits of the enzyme.