1. Nearly 1000 mutations have been described for human haemoglobin (Hb), many of which result in subtle changes to the oxygen transport system. Similar changes have occurred over the course of animal evolution resulting in a diversity of functional attributes which appear to correlate the availability of oxygen in the ...

Nitric oxide (NO) produced by the endothelium diffuses both into the lumen and to the smooth muscle cells according to the concentration gradient in each direction. The extremely high reaction rate between NO and hemoglobin (Hb), k(Hb)= 3-5 x 10(7) M(-1).s(-1), suggests that most of the NO produced would be ...

Human blood contains a form of minimally modified low density lipoprotein (LDL), termed LDL-, whose origin remains unknown. Exploring the mechanism of formation, we found that LDL- can be produced in plasma in the absence of oxygen following LDL incubation with oxidized hemoglobin species. A high degree of apolipoprotein B100 ...

Agnathans, comprising lamprey and hagfish species, have been reported to be practically devoid of HCO3-/Cl- exchange across the red blood cell membrane. This suggests that the capacity of their haemoglobin (Hb) to remove H+ is essential for obtaining a high CO2-carrying capacity in the blood. Hydrogen ion titrations were performed ...

The red blood cell substitutes beta-beta cross-linked (DECA-Hb, XLBV-Hb) and non-cross-linked (HbA) hemoglobins (Hbs), were transfused into rabbits and their effects on hematopoiesis examined. All rabbits receiving DECA-Hb or XLBV-Hb tolerated the Hbs well, whereas 50% of the animals transfused with similar doses of non-cross-linked HbA died. Analysis of peripheral ...

Hemoglobin-based blood substitutes are being developed as oxygen-carrying agents for the prevention of ischemic tissue damage and hypovolemic (low blood volume) shock. The ability of cell-free hemoglobin blood substitutes to affect vascular tone through the removal of nitric oxide has also prompted an evaluation of their usefulness for maintaining blood ...

S-Nitrosation of cysteine beta93 in hemoglobin (S-nitrosohemoglobin (SNO-Hb)) occurs in vivo, and transnitrosation reactions of deoxygenated SNO-Hb are proposed as a mechanism leading to release of NO and control of blood flow. However, little is known of the oxygen binding properties of SNO-Hb or the effects of oxygen on transnitrosation ...

CONTEXT: The hemoglobin (Hb) level is the most-used parameter for screening blood donors for the presence of anemia, one of the most-used methods for measuring Hb levels is based on photometric detection of cyanmetahemoglobin, as an alternative to this technology, HemoCue has developed a photometric method based on the determination ...

PURPOSE: This study investigated the vasoconstrictive effects of both stroma-free and liposome-encapsulated cross-linked hemoglobin (Hb) on vascular plexus hemodynamics, using the choroid of the rabbit eye as a model system. METHODS: Sequential subtraction of high-speed ICG fluorescence angiogram images facilitated visualization of the time-varying patterns of blood flow distribution in ...

Blood substitutes are oxygen-carrying plasma expanders intended to be used instead of blood. Their development is a long-standing quest and seen as being one of the several most important prizes of biotechnology. Their value, both in the clinic and market place, is virtually limitless. Most of the emphasis today, both ...

BACKGROUND: Measurements of cerebral haemoglobin oxygenation of 2 near-infrared spectroscopy devices (INVOS 3100 and NIRO 500) were compared during and after hypocapnia. METHODS: Fifteen awake, healthy volunteers, who hyperventilated to obtain end-tidal CO2 (EtCO2) values of approximately 20 mmHg, were studied. During hyperventilation and 8 min thereafter, EtCO2, INVOS 3100 ...

The management of recombinant human erythropoietin (rHuEPO) treatment in hemodialysis patients requires close monitoring of iron status, because the pharmacologically stimulated erythropoiesis is particularly dependent on a continuous supply of iron. Parameters commonly measured to assess iron status are serum ferritin and the transferrin saturation. Both are indirect measures of ...

OBJECTIVES: The possible oxidative complications induced by free hemoglobin (Hb) released during the blood storage are discussed together with therapeutic strategies using vitamin E and specific inhibitor haptoglobin. Prooxidative properties of Hb in blood have been examined using LDL as a marker for oxidative stress, which contribute to toxicity observed ...

Phospholipid vesicles encapsulating purified hemoglobin (HbV) were developed to provide O2-carrying capacity to plasma expanders. Microvascular perfusion was determined for HbV with different O2 affinity (P50 = 9, 16, and 30 mmHg) prepared by coencapsulating pyridoxal 5'-phosphate (PLP) at the molar ratios of [PLP]/[Hb] = 0, 0.5, and 3, respectively ...

Concern about potential infective agents in donated blood has stimulated the recent development of blood substitutes. Chemically cross-linked hemoglobins are already undergoing clinical trials and might soon be ready for routine use. New generations of modified hemoglobin are being prepared to modulate the effects of nitric oxide and oxygen radicals, ...

The cardiovascular effects of human albumin (Alb) and three human hemoglobin (Hb) solutions, dextran-benzene-tetracarboxylate Hb, alphaalpha-crosslinked Hb, and o-raffinose-polymerized Hb were compared in anesthetized rabbits undergoing acute isovolemic hemodilution with Hct reduction from 41.4 +/- 2.7 to 28.8 +/- 1.6%. The impact of the vasoconstricting properties of Hb was examined ...

In order to further define the influence of microvessel diameter on intraluminal oxygen transport a previously described in vitro artificial capillary system was modified from a vessel diameter of 25 microns to 10 microns. Oxygen uptake and release rates were measured for hemoglobin solutions and red blood cell (Rbc) suspensions ...

The problems posed by transfusion of homologous blood have led to the development of substances able to replace the gas transporting properties of blood. Perfluorocarbons (PFCs) emulsions and modified haemoglobin (Hb) solutions have been developed for this goal and are now tested in clinical assays. PFCs are synthetic fluorinated hydrocarbons, ...

We examined the effect of a prolonged dive on measures of oxidative stress in human divers. Ten subjects, wearing dry suits, completed mental tasks while lying quietly at 4.6 m fresh water for 3.5 h. Subjects (9 male, 1 female) were active, experienced divers ranging in age from 19 to ...

Hemoglobin solutions are potential resuscitative fluids with volume expanding and oxygen delivery abilities developed to reduce the use of blood transfusion. Most hemoglobin solutions in clinical trials increase transiently arterial pressure by inhibiting nitric oxide-dependent vasodilation. Our objective was to compare the effects on central hemodynamics and carotid blood flow ...

The effect of intermittent hypoxia (IHx) on blood hemoglobin concentration ([Hb]) and the underlying mechanisms were studied in rats exposed to 10% O2, 1 h/day, for up to 5 wk. IHx protocols with longer daily hypoxic exposure show persistent polycythemia; however, it is unknown whether [Hb] increases transiently during hypoxia ...

Early approaches to the development of oxygen carriers involved the use of stroma-free hemoglobin solutions. These solutions did not require blood typing or crossmatching and could be stored for long periods. In addition, a variety of methods have been developed in chemically modifying and stabilizing the hemoglobin molecule. Several hemoglobin ...

Theoretically, if the arterial partial oxygen pressure (PaO2) does not change, a right shift in the oxygen equilibrium curve (OEC) of hemoglobin should reduce arterial oxygen saturation. In this study we investigate whether a right shift in the OEC of hemoglobin decreases transcutaneous oxygen saturation (Tc-SO2) following the administration of ...

Prospects for safe and effective blood substitutes are promising, based on clinical trial results of soluble hemoglobin solutions and emulsion of perfluorocarbins. Advantages of blood substitutes include sterilization of viral and bacterial contaminants, room temperature storage, a long shelf life, and absence of ABO and other red cell antigens. Projected ...

The aim of this study was to investigate the permeation behavior of a large molecule through a venous wall; hemoglobin was chosen as a model substance. In vitro experiments were performed using a Chien-Valia diffusion chamber. Postmortem, hemolyzed, and fresh nonhemolyzed blood samples were investigated as permeants. Vein patches from ...

BACKGROUND: Hemoglobin-based blood substitutes appear poised to deliver the promise of a universally compatible, disease-free alternative to banked blood. However, vasoconstriction following administration of tetrameric hemoglobins has been problematic, likely because of nitric oxide binding. Polymerized hemoglobin is effectively excluded from the abluminal space because of its size, and is ...

OBJECTIVE: To evaluate the accuracy of 3 automated methods of determining Hct and hemoglobin (Hb) concentration, compared with manual methods. Animals-22 clinically normal adult horses of various breeds. PROCEDURE: A blood sample was obtained from each horse. Six dilutions (representing Hct of 0, 10, 20, 40, 60, or 70%) were ...

We describe an HPLC-based method for the detection and quantification of fetal hemoglobin in stools of newborns. The new procedure is an alternative to the classic qualitative test for adult hemoglobin in meconium based on the differential stability of hemoglobin species in dilute base (Apt test). The HPLC method, based ...

Two near-infrared spectroscopy (NIRS) methods are available for measuring changes (Delta) in total cerebral hemoglobin concentration (CHC): 1) a continuous measurement of the changes in total hemoglobin concentration (Delta[Hb]tot) and 2) the difference between two absolute measurements of CHC, each derived from a small, controlled change in inspired O2 fraction. ...

Neo red cells (NRCs) are a blood substitute representing stroma free hemolysate (SFHL) encapsulated in liposomes and containing NAD, glucose, adenine, and inosine, etc. as substrates or coenzymes of the Embden-Meyerhof pathway in RBCs and inositol hexaphosphate (IHP) as an allosteric effector. The oxygen transport efficiency (OTE) of NRCs was ...

Time courses of total (GSH-t), disulfide (GSSG), and mixed disulfide (PSSG) forms of glutathione were studied in chicken blood submitted to oxidative stress induced by diamide or by the reactive oxygen species (ROS)-producing system xanthine/xanthine oxidase (X/XO). Diamide-treated blood induced an immediate increase in GSSG and PSSG, while X/XO produced ...

Three different levels of hyperchloremia were induced in healthy Friesian calves to study the effects of chloride on blood oxygen transport. By infusion, the calves received either 5 ml/kg of 0.9% NaCl (low-level hyperchloremia; group A), 5 ml/kg of 7.5% NaCl (moderate hyperchloremia; group B), or 7.5 ml/kg of 7.5% ...

Some recent reports showed that a brief exposure to a mental stressor during 3-20 min may induce hematological changes in humans. The aim of the present study was to examine the effects of academic examination stress on erythron variables, such as the number of red blood cells (RBC), hemoglobin (Hb), ...

Hemoglobin E (HbE; alpha2beta226glu-lys), globally the commonest hemoglobin variant, is synthesized at a slightly reduced rate and has a homozygous phenotype similar to heterozygous beta thalassemia. Yet, when it is inherited together with a beta thalassemia allele, the resulting condition, HbE/beta thalassemia, is sometimes characterized by a severe, transfusion-dependent thalassemia ...

BACKGROUND: Hemoglobin-based blood substitutes may cause vasoconstriction, which could limit organ perfusion during trauma resuscitation. We investigated the effect of two hemoglobin solutions on regional blood flow and mucosal perfusion in the gastrointestinal tract in a hemorrhagic shock model. METHODS: Twenty-four swine were bled 30% of blood volume over 1 ...

Glucose-6-phosphate dehydrogenase (G6PD) deficiency affects an estimated 400 million people. Most of the individuals affected live in Africa, the Middle East and Southeast Asia, or are African-Americans. The ethnic distribution of G6PD-deficiency is extremely variable in Israel--where the Jewish population has been repatriated from more than 60 different countries--its prevalence ...

Patients with the nondeletion genotype of hemoglobinopathy H (HbH or beta4) disease have higher proportions of HbH and more severe tissue hypoxia than patients with the deletion genotype. Because these patients' red blood cells (RBCs) contain mainly two Hb species, HbH and HbA, the high proportion of HbA can be ...

Individual polymers at thermal equilibrium were exposed to an elongational flow producing a high strain rate, and their dynamics were recorded with video fluorescence microscopy. The flow was turned on suddenly so that the entire evolution of molecular conformation could be observed without initial perturbations. The rate of stretching of ...

Cyclical fluctuations in cerebral blood flow velocity in Doppler measurements are a well known phenomenon. In 1992 Livera et al have shown in one patient, that cyclical fluctuations of cerebral blood volume could be measured with near infrared spectroscopy (NIRS). The aim of the present study was a quantification of ...

BACKGROUND: Human polymerized hemoglobin (PolyHeme) is a universally compatible, disease-free, oxygen-carrying resuscitative fluid. This is the first prospective, randomized trial to compare directly the therapeutic benefit of PolyHeme with that of allogeneic red blood cells (RBCs) in the treatment of acute blood loss. STUDY DESIGN: Forty-four trauma patients (33 male, ...

BACKGROUND AND PURPOSE: In normal subjects, regional cerebral blood flow (rCBF) is greatly increased by neuronal activity, whereas the cerebral metabolic rate for O2 is increased only slightly. However, it is not clear what kinds of cerebral blood oxygenation and hemodynamic changes can be induced by language activities in language-relevant ...

Mössbauer spectra of 12 beta-thalassemia/hemoglobin E spleen samples from Thai patients who had not received multiple blood transfusions and chelation therapy and seven beta-thalassemia spleen samples from Australian patients who had received multiple blood transfusions and chelation therapy were recorded with sample temperatures of 78 K. Each spectrum was found ...

A technique is described for opening the membrane of a red blood cell by electroporation in a manner which permits free exchange of the native hemoglobin with exogenous hemoglobin in the surrounding medium. After resealing the RBC's demonstrate near normal size and hemoglobin content and retain an effective methemoglobin reduction ...

In this study we examined transferrin (Tf) and hemoglobin (Hb) types and frequencies and their relationship with Packed Cell Volume (PCV), which is considered as a selection criterion for the trypanotolerance trait. Blood samples were collected from 96 sheep and were typed for Tf and Hb. The frequencies of the ...

We investigated the effects of modified hemoglobin on regional blood flow and function of different organs during hyperdynamic sepsis. Fourteen sheep were surgically prepared for the study. After a 5-day recovery period, a continuous infusion of live Pseudomonas aeruginosa bacteria was begun and maintained for 48 h. At 24 h, ...

The purpose of this study was to evaluate the ability of indolinic and quinolinic nitroxide radicals to protect trout (Salmo irideus) erythrocytes against oxidative stress. By using laurdan as a fluorescence probe, it was observed that the nitroxides inhibited the shift towards a gel phase of liposomes prepared with phospholipids ...

Splanchnic mucosal perfusion abnormalities have been implicated in the development of sepsis and multiorgan failure. We employed reflectance spectrophotometry for direct assessment of the microvascular hemoglobin oxygen saturation (HbiO2) and hemoglobin concentration (rel Hb(conc)) in the mucosa of the upper gastrointestinal tract. Owing to the high recording frequency together with ...

Most of hemoglobin-based oxygen carriers (HBOCs) increase the blood pressure after injection in the blood stream by a mechanism involving one or more factors that contribute to the regulation of the vascular tone. Many techniques make it possible to study the vascular effects of HBOCs both in vivo and in ...

According to the International Committee for Standardization in Haematology (ICSH), we determined the reference values for reticulocytes using an automated blood cell analyzer Technicon H*3 RTC in 200 healthy adult blood donors, aged between 17 and 60 years, 100 of whom were male and 100 female. The parameters included reticulocyte ...

OBJECTIVE: Adenosine 5'-triphosphate (ATP) causes vasoconstriction by activation of P2-purinoceptors on vascular smooth muscle cells. Erythrocytes contain ATP at a concentration (1.6 mmol/L) that contracts smooth muscle. Previous studies of hemoglobin solutions did not assess whether the vasoactivity was caused by ATP rather than or in addition to hemoglobin. It ...