On temperature factor and the effect of viscosity on blood temperature in the arteries

A mathematical theory which could be used to explain a clinical observation in some sickle-cell anemia patients is proposed. It is shown that if the energy stored in the elastic walls of the artery of such a patient is accompanied by thermal effects, then the existence of a local hot spot on the body of a sickle-cell anemia patient could be due to shock formation even when the viscosity of the blood is zero. On the other hand, if the energy stored is not accompanied by thermal effects, then a jump in the temperature can only occur if the viscosity is not zero. We give the location of such a jump in the temperature and the time of its occurrence in both cases.     

Clinical use of blood,blood components and blood products.

The goal of modern transfusion therapy is to provide appropriate replacement therapy with blood components as opposed to whole blood for patients with specific hematologic deficiencies. A prerequisite of component therapy is, therefore, correct identification of the deficiency. Appropriate use of components avoids many of the hazards associated with the use of whole blood, and at the same time makes maximal use of this valuable resource. Blood components separated from whole blood soon after collection and appropriately stored can, in combination, provide all the factors present in fresh whole blood. Red cell concentrates prepared from multiple packs have a hematocrit of approximately 70%. They may be stored for up to 3 weeks at 4 degrees C and are recommended for most situations requiring red cell transfusions. Platelet concentrates, which can be stored for up to 72 hours at 22 degrees C, may be used for thrombocytopenic patients. Fresh frozen plasma, stored plasma, cryoprecipitated factor VIII, factor VIII concentrate and factor IX complex concentrate are available for the proper treatment of patients with hemorrhagic disorders due to coagulation factor deficiencies. Similarly, albumin and immune serum globulin are available for their oncotic and antibody properties respectively. Thus, the availability and appropriate use of the various blood products allows not only optimal transfusion therapy for each patient, but also fuller utilization of national blood resources.     

Long-term storage of blood samples at freezing temperatures in the presence of a cryoprotectant for hemiglobin assay

Changes in Hi levels in experimentally prepared blood samples during storage at various temperatures were studied. When whole blood in which Hi levels were elevated by sodium nitrite was stored unfrozen, rapid reduction of Hi was observed within 24 hr even at 0 degrees C. When whole blood or a diluted hemolysate was stored frozen for a week or longer, considerable formation of Hi by autoxidation was observed, the formation at -20 degrees C being much more significant than that at -30 degrees C. On the other hand, addition of an equal volume of the cryoprotectant solution of Rowe et al. to blood almost completely inhibited this Hi formation during freezing storage until at least 30 days. Thus, a new method for long-term storage of blood samples for Hi assay was devised.     

A mathematical model for the decay of conserved blood

In the present paper a simple model is presented by means of which a decay of stored blood can be predicted. The following factors are incorporated in the calculation: The relation of the depot stock to the average number of cross matchings per day, the probability of transfusions, the time reserved for crossed stored blood and that which is not transfused as well as the percentage of stored blood already reserved when arriving at the depot.     

Quality parameters of cryoprecipitates from stored blood preservation

The investigations of a series of 281 cryoprecipitates produced from blood stored at 10 degrees C for 12-18 hours resulted in equal values as compared with those preparations from a control group of 53 preparations which had been prepared from blood maximally stored for 4 hours. Thus, international experiences could be confirmed. An improvement in the quality of erythrocyte concentrates simultaneously produced can be regarded as an additional advantage with respect to the formation of microaggregates during the time the stored blood can be made use of.     

The effect of increasing glucose in CPD on the quality of stored blood

Changes in quality of blood units containing one and a half or double amounts of glucose, stored at +4 degrees C for three weeks were analysed. An experimental preservative containing glucose and fructose (1 : 1) was also used. No other additives (purine or purine-nucleoside) were applied. A standard CPD preservative of the National Inst. of Haematology and Blood Transfusion was used as control. The pH, plasma free haemoglobin, K+ content, red blood cell (RBC) ATP and 2,3-DPG content, and RBC fragility index were determined in each sample. Increase of glucose concentration, the addition of fructose had a beneficial effect on blood pH, and on plasma free haemoglobin and K+ concentration. 150% glucose improved the 2,3-DPG maintenance in stored blood.     

The effect of storage on whole blood chemiluminescence measurement of equine neutrophils

The aim of this study was to determine the effect of duration and temperature of sample storage on whole blood chemiluminescence measurement results. Venous blood from 18 clinically healthy Polish half‐bred horses aged 4 to 11 years were used in the study. Luminol dependent chemiluminescence (CL) was used to measure neutrophil oxygen metabolism in whole blood. Blood samples were examined for spontaneous CL and stimulated by a surface receptor stimulus as well as extra‐receptor stimulus. The assay was performed in two parallel experimental sets with samples stored at 4 and 22 °C, respectively. Whole blood CL was estimated at 2, 6, 24, 48, 72, 96 and 120 h after collection. The study demonstrated that temperature and duration of sample storage are factors that determine the quality of CL measurements of whole blood in horses. The study concluded that samples should be stored at 4 °C and the assay should be performed as early as possible. It was also shown that the viability period of horse blood for CL assays is relatively long. Material stored at room temperature for 24 h and even up to 48 h at 4 °C did not show any significant decrease in spontaneous or stimulated chemiluminescence. Copyright © 2012 John Wiley & Sons, Ltd.     

Red blood cell washing,nitrite therapy,and antiheme therapies prevent stored red blood cell toxicity after trauma–hemorrhage

Transfusion of stored red blood cells (RBCs) is associated with increased morbidity and mortality in trauma patients. Pro-oxidant, pro-inflammatory, and nitric oxide (NO) scavenging properties of stored RBCs are thought to underlie this association. In this study we determined the effects of RBC washing and nitrite and antiheme therapy on stored RBC-dependent toxicity in the setting of trauma-induced hemorrhage. A murine (C57BL/6) model of trauma–hemorrhage and resuscitation with 1 or 3 units of RBCs stored for 0–10 days was used. Tested variables included washing RBCs to remove lower MW components that scavenge NO, NO-repletion therapy using nitrite, or mitigation of free heme toxicity by heme scavenging or preventing TLR4 activation. Stored RBC toxicity was determined by assessment of acute lung injury indices (airway edema and inflammation) and survival. Transfusion with 5 day RBCs increased acute lung injury indexed by BAL protein and neutrophil accumulation. Washing 5 day RBCs prior to transfusion did not decrease this injury, whereas nitrite therapy did. Transfusion with 10 day RBCs elicited a more severe injury resulting in ~90% lethality, compared to <15% with 5 day RBCs. Both washing and nitrite therapy significantly protected against 10 day RBC-induced lethality, suggesting that washing may be protective when the injury stimulus is more severe. Finally, a spectral deconvolution assay was developed to simultaneously measure free heme and hemoglobin in stored RBC supernatants, which demonstrated significant increases of both in stored human and mouse RBCs. Transfusion with free heme partially recapitulated the toxicity mediated by stored RBCs. Furthermore, inhibition of TLR4 signaling, which is stimulated by heme, using TAK-242, or hemopexin-dependent sequestration of free heme significantly protected against both 5 day and 10 day mouse RBC-dependent toxicity. These data suggest that RBC washing, nitrite therapy, and/or antiheme and TLR4 strategies may prevent stored RBC toxicities.     

Cryopreservation of isolated blood vessels

Canine saphenous veins were immersed in fetal calf serum (FCS) containing various cryoprotective agents, slowly frozen and stored for several weeks at subzero temperatures. Pharmacological investigations of frozen/thawed tissues revealed considerable attenuation of the contractile force of frozen stored veins as compared to unfrozen veins. The best recovery after thawing of frozen stored canine veins was obtained on tissues which had been frozen slowly to -70 degrees C and stored in liquid nitrogen while being immersed in FCS containing 1.8 mol/l dimethyl sulfoxide (DMSO). Though the maximum response to noradranline of helical strips prepared from these veins was diminished to about 60% the evidence suggests that there may be a very good preservation of the main biochemical properties, such as monoamine oxidase activity, endogenous prostaglandin synthesis and neuronal uptake mechanism in veins stored under these conditions. The same method of cryopreservation was applied to store samples of human veins. Comparison of the pD2 values for various agonists and of the blocking activities of various antagonists of both 5-HT receptors and alpha-adrenoceptors yielded an excellent correlation between the parameters determined on frozen/thawed and unfrozen human veins. It is concluded that freezing isolated blood vessels may be considered an effective means of preserving and storing vascular tissues for pharmacological investigations.     

Freeze drying cattle blood typing reagents*

A system is described for freeze drying and storage of reagents (antisera) used in cattle blood typing tests. Reagents were freeze-dried in evacuated bottles at the desired dilution for rapid reconstitution to use in test procedures. Reagents not in current use were dried in bulk lots and stored in polyethylene film bags. All freeze drying procedures were performed with readily available commercial equipment. A computer program was developed to produce a current inventory of reagent supplies and projections of the number of samples which can be typed.     

Measurement of adenosine triphosphate and 2,3-diphosphoglycerate in stored blood with 31P nuclear magnetic resonance spectroscopy

Conditions for blood storage are chosen to assure adequate levels of adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG). Because of the invasive nature of the techniques, biochemical assays are not routinely used to measure levels of these compounds in stored blood. However, 31P NMR spectroscopy measures phosphorylated intermediates in intact cells and could be used without disruption of the storage pack. We compared levels of ATP and 2,3-DPG measured by 31P spectroscopy and standard enzyme-linked biochemical assays in whole blood (WB) and packed red blood cells (PRBCs) at weekly intervals during a 35-day storage period. NMR demonstrated a marked decrease in 2,3-DPG and an increase in inorganic phosphate after the first week of storage. No significant differences in ATP concentrations were seen in WB during the storage period, but a significant decrease in ATP in PRBCs was documented. There was good agreement in levels of ATP and 2,3-DPG measured by NMR and biochemical techniques. 31P NMR spectroscopy is a noninvasive technique for measuring ATP and 2,3-DPG which has a potential use in quality assurance of stored blood.     

Preparing platelet concentrates from banked blood stored for 1-5 days by using tetracycline antibiotics

It was shown that storage of banked blood up to five days did not change number of platelets and their functional integrity was retained rather well. That made possible the development of a method for preparation of viable platelet concentrates (PC) from stored blood. This method is based on the reversibility of the tetracycline antibiotics inhibitory effect on platelet activation process. According to the results of our in vitro studies PC from stored blood seem to be suitable for clinical usage. This tetracycline method of PC preparation from stored blood may provide a more efficient utilization of available donor blood to meet the ever-expanding needs for PC transfusions.     

Platelet function in stored heparinised autologous blood is not superior to in patient platelet function during routine cardiopulmonary bypass

Background

In cardiac surgery, cardiopulmonary bypass (CPB) and unfractionated heparin have negative effects on blood platelet function. In acute normovolemic haemodilution autologous unfractionated heparinised blood is stored ex-vivo and retransfused at the end of the procedure to reduce (allogeneic) transfusion requirements. In this observational study we assessed whether platelet function is better preserved in ex vivo stored autologous blood compared to platelet function in the patient during CPB.

Methodology/Principal Finding

We measured platelet aggregation responses pre-CPB, 5 min after the start of CPB, at the end of CPB, and after unfractionated heparin reversal, using multiple electrode aggregometry (Multiplate®) with adenosine diphosphate (ADP), thrombin receptor activating peptide (TRAP) and ristocetin activated test cells. We compared blood samples taken from the patient with samples taken from 100 ml ex-vivo stored blood, which we took to mimick blood storage during normovolemic haemodilution. Platelet function declined both in ex-vivo stored blood as well as in blood taken from the patient. At the end of CPB there were no differences in platelet aggregation responses between samples from the ex vivo stored blood and the patient.

Conclusion/Significance

Ex vivo preservation of autologous blood in unfractionated heparin does not seem to be profitable to preserve platelet function.     

Caching behaviour by eastern woodrats,Neotoma floridana,in relation to food perishability

Two experiments were conducted on eastern woodrats to determine whether the preference for food items gathered for their caches and the sequence of use of items in the cache varied with perishability. In the first experiment, woodrats were given either 2 kg each of two non-perishable items, laboratory chow and bur oak acorns (which they used more than chow), or 2 kg each of preferred, but perishable, grapes and the non-perishable chow. As hypothesized, the woodrats both ate and stored acorns when they were paired with chow (there would be no advantage to either eating or storing the less-used chow). In contrast, when given grapes and chow, the woodrats continued to eat grapes but stored primarily chow. That is, the utility of the items appeared to change depending on whether they were to be eaten or stored. In the second experiment, woodrats were given excess amounts of chow or grapes that were 2, 4, 6 and 8 days old. They ingested chow in the proportions available, as the chow did not spoil with age. However, the consumed grapes in proportions significantly different from those available. It was anticipated that they would eat the oldes grapes first and store the freshest grapes, but neither this pattern nor any other was obvious in ralation to the age of the grapes. The results suggest that woodrats discriminate between food items based on their perishability, and vary their decisions about what to ingest and store accordingly.     

The oxygen transport function of the blood and of the erythrocyte concentrate during storage and its importance for blood transfusion

The property of oxygen transport function was investigated in blood which had been stored in solutions of "glugizir" and "zitroglucophosphate" and in erythrocyte concentrates gained from it on the noughth, 7th, 14th und 21st day of storage at -4 +/- 2 degrees C. The parameters of the oxygen binding function (oxygen content of erythrocytes, half time of haemoglobin saturation with oxygen, concentration of organic phosphate [2.3 diphosphoglycerate and adenosine triphosphate] and those of inorganic phosphorus were determined in erythrocytes. During storage for more than 21 days no significant differences could be detected in the property of oxygen transfer between erythrocytes of stored blood and erythrocyte concentrate, with the values for storing in zitroglucophosphate being somewhat higher. Problems of applying all components of donor blood efficiently are discussed. In performing an adequate haemotherapy with blood components the importance of a functional condition of erythrocytes and oxygen balance in the organism of the receiver should be considered. The necessity of transfusing erythrocyte concentrate in the therapy of anaemias of different genesis is emphasized and the differences in applying concentrates in different plasma solutions are referred to. By transfusing concentrates the effectiveness of hemotherapy are elevated and the rate of complications and side-effects of whole blood are diminished.     

Fine-Grained,Local Maps and Coarse,Global Representations Support Human Spatial Working Memory

While sensory processes are tuned to particular features, such as an object''s specific location, color or orientation, visual working memory (vWM) is assumed to store information using representations, which generalize over a feature dimension. Additionally, current vWM models presume that different features or objects are stored independently. On the other hand, configurational effects, when observed, are supposed to mainly reflect encoding strategies. We show that the location of the target, relative to the display center and boundaries, and overall memory load influenced recall precision, indicating that, like sensory processes, capacity limited vWM resources are spatially tuned. When recalling one of three memory items the target distance from the display center was overestimated, similar to the error when only one item was memorized, but its distance from the memory items'' average position was underestimated, showing that not only individual memory items'' position, but also the global configuration of the memory array may be stored. Finally, presenting the non-target items at recall, consequently providing landmarks and configurational information, improved precision and accuracy of target recall. Similarly, when the non-target items were translated at recall, relative to their position in the initial display, a parallel displacement of the recalled target was observed. These findings suggest that fine-grained spatial information in vWM is represented in local maps whose resolution varies with distance from landmarks, such as the display center, while coarse representations are used to store the memory array configuration. Both these representations are updated at the time of recall.     

Acorns,insects, and the diet of adult versus nestling Acorn Woodpeckers

ABSTRACT The diet of Acorn Woodpeckers (Melanerpes formicivorus) in central coastal California consists of a mixture of high‐quality (insects) and low‐quality (stored acorns) food during the spring breeding season. We used stable isotope ratios obtained from blood samples to estimate possible differences in the proportion of these items being fed to nestlings and being consumed by breeding adults, as well as the extent to which the diet of nestlings shifts between insects and acorns during the nestling period. Based on both feeding observations and items recovered from nestlings, older nestlings were fed 28% acorns. Using this value as a baseline for the isotope analyses, the diet of breeding adults was estimated to consist of 90% acorns. Based on repeated samples from the same nestlings over time, the estimated proportion of acorns in their diet increased from 19% in 9‐ to 12‐d‐old nestlings to 42% in 23‐ to 26‐d‐old nestlings. There was a significant correlation between the isotope values of adults and the nestlings they fed, indicating that different groups of Acorn Woodpeckers have significantly different diets. Although important for successful reproduction in this species, stored acorns are not the primary food resource used to feed young. Instead, the availability of stored acorns allows adult Acorn Woodpeckers to provide nestlings with more protein‐rich insects while maintaining themselves on relatively protein‐poor, low‐quality acorns. Differences in the diets of adults and their nestlings are likely widespread among species that feed, at least in part, on low‐quality foods, such as fruit and seeds, during the breeding season.     

Comparison of PCR, culture and microscopy of blood smears for the diagnosis of anthrax in sheep and cattle

AIMS: To compare microscopy, culture and PCR for the diagnosis of anthrax in blood samples from sheep and cattle. METHODS AND RESULTS: Blood samples were stored at room temperature and at 37 degrees C after receipt, over a period of 15-17 days. Aliquots were plated onto blood agar and blood smears were prepared. Following microscopic examination, DNA was extracted from blood smears and subjected to a multiplex PCR assay targeting the Ba813, cap and lef markers. CONCLUSIONS: PCR provided the most reliable means for the detection of Bacillus anthracis in deteriorating blood samples (15-17 days) and was also successful in diagnosing anthrax in blood smears that had been stored for 6 years and a blood sample which had been stored for 18 months at -20 degrees C. While less successful than PCR, culture for B. anthracis on 7% sheep blood agar was typically more reliable (2-17 days) than the examination of blood smears (2-6 days) for encapsulated bacilli. SIGNIFICANCE AND IMPACT OF THE STUDY: This work demonstrated the superiority of PCR for the diagnosis of anthrax from blood smear scrapings, particularly when microscopy is unreliable.     

Microcomputer monitor and blood sampler for free-diving Weddell seals

The equipment used for the first sampling of arterial blood at depth on free-diving Weddell seals Leptonychotes weddelli is described. Blood was withdrawn through an aortic catheter by a submersible, peristaltic roller pump and stored in a single- or multiple-sample collection device. The multiple sampler allowed up to eight individual blood samples to be collected during a single dive. The blood pump was controlled by a dedicated microcomputer that allowed initiation of blood sampling at flexible combinations of depth and/or time during either the descending or ascending phase of the dive. The dedicated microcomputer also recorded swimming depth, velocity, heart rate, and body temperature at selectable time intervals. These data were transmitted to a laboratory computer, and blood samples were retrieved, when the seal surfaced to breathe.     

Phagocytosis of formol treated red blood cells

Formol treated red blood cells have been established to be phagocytized by human leukocytes in the presence of compatible AB0 standard test sera in case such red blood cells are stored continuously in water or in case they are incubated in saliva in advance for one hour at least at 37 degrees C. If formol treated red blood cells are continuously stored in 0.9% NaCl solution or if they are lyophilized in addition they will not be engulfed by human leukocytes in presence of compatible standard test sera of the AB0 system. The additional treatment with papain of formol treated red blood cells will cause a moderate phagocytosis.