Initial Hb Concentration Research Articles

A novel lanthanide-chelate based molecularly imprinted cryogel for purification of hemoglobin from blood serum: An alternative method for thalassemia diagnosis

Purification and analyzing of proteins is an essential means for understanding their function and diseases associated with their lack or defect. In this research, a new lanthanide-chelate based molecularly imprinted polymer (MIP) was synthesized for selective separation of Hemoglobin (Hb) from human serum in the presence of various interference molecules. The Hb-imprinted polymer was prepared by using complex functional monomer N-methacryloylamido antipyrine (MAAP)-Ce(III) and 2-Hydroxyethyl methacrylate (HEMA) in accordance of cryopolymerization techniques. The nonimprinted cryogel (NIP) was also prepared at same polymerization conditions in the absence of template Hb molecule. The effects of pH, initial Hb concentration, flow rate, temperature and ionic strength on the binding capacity of both imprinted and nonimprinted cryogels was investigated. The maximum binding capacity for the MIP column was found to be as 79.41 mg g−1 dry cryogel, that is four times higher than the NIP column under the optimum conditions (pH 5.0, flow rate: 1.0 mL min−1, T: 25 °C). Moreover, selectivity experiments were performed by using two interference proteins as myoglobin (Mb) and cytochrome c (Cyt-c) and the relative selectivity coefficients (k') for Hb/Mb and Hb/Cyt-c pairs were determined as 36.59 and 37.22, respectively.

Polychelated cryogels: hemoglobin adsorption from human blood

The separation and purification methods are extremely important for the hemoglobin (Hb) which is a crucial biomolecule. The adsorption technique is popular among these methods and the cryogels have been used quite much due to their macropores and interconnected flow channels. In this study, the Hb adsorption onto the Cu(II) immobilized poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA)-Cu(II), cryogels was investigated under different conditions (pH, interaction time, initial Hb concentration, temperature and ionic strength) to optimize adsorption conditions. The swelling test, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), surface area (BET), elemental and ICP-OES analysis were performed for the characterization of cryogels. Polyethyleneimine (PEI) molecule was used as a Cu(II)-chelating ligand. The Hb adsorption capacity of cryogels was determined as 193.8 mg Hb/g cryogel. The isolation of Hb from human blood was also studied under optimum adsorption conditions determined and the Hb (124.5 mg/g cryogel) was isolated. The adsorption model was investigated in the light of Langmuir and Freundlich adsorption isotherm models and it was determined to be more appropriate to the Langmuir adsorption isotherm model.

Significance of Initial Maternal Hemoglobin Concentration during Pregnancy in Birth Weight and Preterm Delivery in Sri Lanka

Objective: The study was conducted to investigate the influence of initial hemoglobin (Hb) concentration of Sri Lankan pregnant mothers on baby’s birth weight and preterm delivery. Methods: For this retrospective study, 3867 primigravid pregnant women in Sri Lanka were followed till they deliver the baby. Sampling method was cluster sampling where all the pregnant mothers giving singleton birth in the selected 15 health division were followed for three years. Mothers’ initial Hb concentration, weight gain during the pregnancy and neonatal outcomes were assessed. Results: Severe iron deficiency anemia at the initial stage of pregnancy had 3.9 - 14.4 folder higher relative risk of low birth weight (LBW) and 3.0 - 8.1 folder higher relative risk of preterm delivery at 95% confidence interval. The minimum incidence of preterm delivery and maximum weight gain of mothers occurs in association with an initial Hb concentration of 105 - 125 g/L. Conclusion: The excess level of initial iron content at pregnancy does not contribute for any adverse effect on pregnancy outcome as like in the later part of pregnancy and therefore supplement of iron during the initial pregnancy for mothers can be carried out regardless of whether the mother is anemic.

Does repeat Hb measurement within 2hours after a normal initial Hb in stable trauma patients add value to trauma evaluation?

BackgroundIn our level I trauma center, it is considered common practice to repeat blood haemoglobin measurements in patients within 2 h after admission. However, the rationale behind this procedure is elusive and can be considered labour-intensive, especially in patients in whom haemorrhaging is not to be expected. The aim of this study was to assess the value of the repeated Hb measurement (r-Hb) within 2 h in adult trauma patients without evidence of haemodynamic instability.MethodsThe local trauma registry was used to identify all trauma patients without evidence of haemodynamic instability from January 2009 to December 2010. Patients in whom no initial blood Hb measurement (i-Hb) was done on admission, referrals, and patients without risk for traumatic injuries or haemorrhage based upon mechanism of injury (e.g. inhalation or drowning injury) were excluded.ResultsA total of 1,537 patients were included in the study, 1,246 of which did not present with signs of haemodynamic instability. Median Injury Severity Score (ISS) was 5 (interquartile range (IQR) 1 to 13), 22% of the patients were multitrauma patients (ISS > 15). A normal i-Hb was found in 914 patients (73%). Of the 914 patients with a normal i-Hb, 639 (70%) had a normal r-Hb, while in 127 patients (14%), an abnormal r-Hb was found. In none of these patients, the abnormal r-Hb led to new diagnoses. In 148 patients (16%), no repeated Hb measurement was done without clinical consequences.ConclusionWe conclude that repeated blood Hb measurement within 2 h after admission in stable, adult trauma patients with a normal initial Hb concentration does not add value to a trauma patient's evaluation.

Hydrothermal synthesis of hydroxyapatite nanorods and nanowires using riboflavin-5′-phosphate monosodium salt as a new phosphorus source and their application in protein adsorption

Hydroxyapatite (HA), as the main inorganic constituent in vertebrate hard tissues, is an important biomaterial for the application in drug delivery and protein adsorption. Herein, we report a simple and green hydrothermal synthesis of HA nanorods and nanowires by using the biocompatible biomolecule riboflavin-5′-phosphate monosodium salt (RP) as a new phosphorus source. In this method, the RP molecules hydrolyze to form inorganic phosphate ions under hydrothermal conditions, and these phosphate ions react with calcium ions to form HA nanorods or nanowires after nucleation and crystal growth. The effects of experimental conditions including hydrothermal temperature, heating time and pH value of the initial solution on the hydrolysis process of RP molecules are investigated. A possible formation mechanism of HA nanorods and nanowires is proposed. The as-prepared HA nanorods and nanowires are explored for the potential application in protein adsorption. The hemoglobin (Hb) loading capacities of HA nanowires and HA nanorods increase with increasing initial Hb concentration. The Hb loading capacities of HA nanowires and HA nanorods are determined to be as high as 289 mg g−1 and 298 mg g−1, respectively, at an initial Hb concentration of 2000 mg mL−1. The pH-dependent Hb release property of Hb-loaded HA nanowires and HA nanorods has been found. The experimental results indicate that the products are promising for applications in protein adsorption.

Magnetic nanocomposite of hydroxyapatite ultrathin nanosheets/Fe3O4 nanoparticles: microwave-assisted rapid synthesis and application in pH-responsive drug release.

Synthetic hydroxyapatite (HAP) nanostructured materials have been considered as promising biomaterials due to their excellent biocompatibility. In this study, a magnetic nanocomposite consisting of HAP ultrathin nanosheets (UNs) and Fe3O4 magnetic nanoparticles (MNs) has been prepared using a rapid microwave-assisted route. The Fe3O4 magnetic nanoparticles are hybridized with HAP ultrathin nanosheets, which self-assemble to form a hierarchically nanostructured magnetic nanocomposite (HAPUN/MNs). The as-prepared HAPUN/MNs nanocomposite is characterized and investigated as a drug nanocarrier using hemoglobin (Hb) and docetaxel (Dtxl) as model drugs. The adsorption amount of Hb on the HAPUN/MNs nanocomposite increases with the increasing initial Hb concentration. The release of Hb from the HAPUN/MNs nanocomposite is essentially governed by a diffusion process. The HAPUN/MNs nanocomposite has a good sustained release profile for Dtxl, and shows good pH-responsive drug release properties, which can be explained by the gradual dissolution of HAP in a low pH value environment. The HAPUN/MNs nanocomposite has a high biocompatibility and also a high in vitro anticancer effect after loading Dtxl.

Encapsulation of Hemoglobin Using Condensation Reaction of Butylcyanoacetate with Formaldehyde

AbstractSummary: Hemoglobin (Hb)‐encapsulating particles have been prepared in a single step by condensation reaction of butylcyanoacetate (BCNA) with formaldehyde (FA) in Hb aqueous solution. Dimethylamine was used as a base catalyst and then the reaction was performed in 0.1 M HEPES buffer (pH 7.4) at room temperature. Particle composition analysis by extraction indicated that the particles consisted of PBCNA, HEPES and Hb. The content of Hb loaded into the particles monotonously increased with increasing initial Hb concentrations. Almost all Hb molecules in aqueous solution could be recovered as particles. In addition, the encapsulated Hb maintained the oxygen‐carrying capacity similar to native Hb. These results indicate that condensation reaction of BCNA with FA can provide the assembly of Hb molecules in aqueous solution.

Parameters for successful monthly extended dosing of darbepoetin-alpha in patients undergoing hemodialysis

To document the feasibility and report the results of dosing darbepoetin-alpha at extended intervals up to once monthly (QM) in a large dialysis patient population. 175 adult patients treated, at 23 Swiss hemodialysis centres, with stable doses of any erythropoiesis-stimulating agent who were switched by their physicians to darbepoetin-alpha treatment at prolonged dosing intervals (every 2 weeks [Q2W] or QM). Multicentre, prospective, observational study. Patients' hemoglobin (Hb) levels and other data were recorded 1 month before conversion (baseline) to an extended darbepoetin-alpha dosing interval, at the time of conversion, and once monthly thereafter up to the evaluation point (maximum of 12 months or until loss to follow-up). Data for 161 evaluable patients from 23 sites were included in the final analysis. At 1 month prior to conversion, 73% of these patients were receiving darbepoetin-alpha weekly (QW) and 27% of the patients biweekly (Q2W). After a mean follow-up of 9.5 months, 34% received a monthly (QM) dosing regimen, 52% of the patients were receiving darbepoetin-alpha Q2W, and 14% QW. The mean (SD) Hb concentration at baseline was 12.3 +/- 1.2 g/dl, compared to 11.9 +/- 1.2 g/dl at the evaluation point. The corresponding mean weekly darbepoetin-alpha dose was 44.3 +/- 33.4 microg at baseline and 37.7 +/- 30.8 microg at the evaluation point. Conversion to extended darbepoetin-alpha dosing intervals of up to QM, with maintenance of initial Hb concentrations, was successful for the majority of stable dialysis patients.

Biocompatible and Biodegradable Polymersome Encapsulated Hemoglobin: A Potential Oxygen Carrier

This work describes the development of polymersome-encapsulated hemoglobin (PEH) self-assembled from biodegradable and biocompatible amphiphilic diblock copolymers composed of poly(ethylene oxide) (PEO), poly(caprolactone) (PCL), and poly(lactide) (PLA). In the amphiphilic diblock, PEO functions as the hydrophilic block, while either PCL or PLA can function as the hydrophobic block. PEO, PCL, and PLA are biocompatible polymers, while the last two polymers are biodegradable. PEH dispersions were prepared by extrusion through 100 nm pore radii polycarbonate membranes. In this work, the encapsulation efficiency of human and bovine hemoglobin (hHb and bHb) in polymersomes was adjusted by varying the initial concentration of Hb. This approach yielded Hb loading capacities that were comparable to values in the literature that supported the successful resuscitation of hamsters experiencing hemorrhagic shock. Moreover, the Hb loading capacities of PEHs in this study can also be tailored simply by controlling the diblock copolymer concentration. In this study, typical Hb/diblock copolymer weight ratios ranged 1.2-1.5, with initial Hb concentrations less than 100 mg/mL. The size distribution, Hb encapsulation efficiency, oxygen affinity (P 50), cooperativity coefficient (n), and methemoglobin (metHb) level of these novel PEH dispersions were consistent with values required for efficient oxygen delivery in the systemic circulation. Taken together, our results demonstrate the development of novel PEH dispersions that are both biocompatible and biodegradable. These novel dispersions show very good promise as therapeutic oxygen carriers.

Stability of Liposome Encapsulated Hemoglobin Dispersions

The demand for artificial blood substitutes in cases of elective surgeries, trauma, and civilian mass catastrophes increases every day. However, few studies have been done to characterize the mechanical stability of blood substitutes, especially liposome encapsulated hemoglobin (LEHb) dispersions. In this work, the stability of LEHb dispersions was investigated by fitting Jung et al.'s liposome size distribution model to experimentally measured LEHb size distributions [6] (produced via extrusion) using asymmetric flow field-flow fractionation coupled with multi-angle static light scattering. The effective bending constant (KB) and radius of curvature (R0) of each liposome dispersion were regressed from the size distribution fits. The model was found to be in agreement with the size distributions of LEHbs extruded through 400, 200 and 100 nm pore diameter membranes, but not in agreement with LEHbs extruded through 80 and 50 nm pore diameter membranes. Although the magnitude of KB fluctuated, we deduced a general trend for KB to decrease with decreasing pore diameter, and increasing initial Hb concentration. LEHbs extruded through 400nm pore diameter membranes were stabilized by the spontaneous curvature effect, while those extruded through 80 and 50 nm pore diameter membranes were mostly stabilized by thermal undulations, regardless of the initial Hb concentration. For LEHb dispersions extruded through 200 and 100 nm pore diameter membranes, there was a transition of stabilization mechanism from spontaneous curvature to thermal undulations with increasing initial Hb concentration. Taken together, these results suggest that moderate Hb encapsulation might actually impart better mechanical stability to LEHb dispersions extruded through 200 and 100 nm pore diameter membranes.

Purification and characterization of liposomes encapsulating hemoglobin as potential blood substitutes.

In view of the desirability to increase the survival time of the liposome-based artificial red blood cells in vivo, the variables influencing optimum hemoglobin capture and preservation for the bovine hemoglobin-loaded liposomes (LEHb) are investigated. In order to predict the in vivo response, the necessary experiments for the in vitro system characterization have been carried out. The liposomes are prepared by the Reverse Phase Evaporation technique and then purified using a Sepharose 4B column. The purified LEHbs display a unimodal size distribution in the submicron range with a volume average diameter of 0.115 microns and a particle count of 1.25* 10(15) per ml of suspension. Analysis of the lipi/Hb content of the liposomes reveals that the variations in the ratio of Hb encapsulated to lipid entrapped (Hb/L)f as a function of the initial Hb concentration ([Hb]o) is insignificant compared to the net augmentation of (Hb/L)f as a function of the increasing initial lipid to Hb loading ([L]o). Meanwhile high [Hb]o s are necessary for the preservation of oxyhemoglobin.

Parity as a Determinant of the Hematologic Response to Hematinics Supplementation in Underprivileged Pregnant Women in Malaysia

The effect of parity on the hematological response to supplemental hematinics and the relationship between birth weight and Hb concentration were examined in 67 pregnant rural Kelantanese Malay women recruited at 20-24 weeks of gestation. Among initially anemic women (Hb concentration at recruitment < 110 g/l), a significant supplementation effect was observed in the lower parae (3 or less children) but not in the higher parae. Among initially nonanemic women, a progressive decline in mean Hb concentration was observed in the higher parae; in the lower parae, however, an initial fall in mean Hb concentration was followed by a rise to almost the initial level. Birth weight was inversely related to initial Hb concentration. There was no association between birth weight and final measured Hb level, parity or any of the measured maternal characteristics. These observations suggest: a) women with initially lower Hb concentration might have experienced a greater acceleration of plasma volume expansion than those with initially higher Hb level; and b) hemopoiesis might be impaired in the higher multiparae.