scholarly journals One-Fifth of Children with Sickle Cell Anemia Show Exercise-Induced Hemoglobin Desaturation: Rate of Perceived Exertion and Role of Blood Rheology

2020 ◽  
Vol 9 (1) ◽  
pp. 133
Author(s):  
Valentine Brousse ◽  
Corinne Pondarre ◽  
Cecile Arnaud ◽  
Annie Kamden ◽  
Mariane de Montalembert ◽  
...  
Keyword(s):  
Heart Rate ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Perceived Exertion ◽  
Blood Rheology ◽  
Limiting Factor ◽  
Rate Of Perceived Exertion ◽  
And Performance ◽  
Exercise Induced

Perceived exertion is an important self-limiting factor influencing functional capacity in patients with sickle cell anemia (SCA). Exercise-related hemoglobin desaturation (EHD) may occur during a six-minute walking test (6MWT) and could influence the perceived rate of exertion. The aims of this study were (1) to compare the 6MWT responses (heart rate, perceived rate of exertion, and distance covered) between SCA children with and without EHD, and (2) to test the associations between EHD and several biological/physiological parameters. Nine of 51 SCA children (18%) at steady state (mean age 11.9 ± 3.8 years) exhibited EHD at the end of the 6MWT. The rate of perceived exertion increased with exercise in the two groups, but reached higher values in the EHD group. Heart rate and performance during the 6MWT did not differ between the two groups. The magnitude of change in SpO2 during the 6MWT was independently associated with the red blood cell (RBC) deformability and RBC aggregates strength. This study demonstrates that SCA children with EHD during a 6MWT have a higher rate of perceived exertion than non-EHD children despite a similar physiological demand, and that abnormal RBC rheology determinants appear to be significant contributors.

The orientation of sickle hemoglobin fibers within fascicles

1988 ◽  
Vol 46 ◽  
pp. 400-401
Author(s):  
Christopher A. Miller ◽  
Bridget Carragher ◽  
William A. McDade ◽  
Robert Josephs
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Relative Orientation ◽  
Unit Cell ◽  
Red Cell ◽  
High Ph ◽  
Sickle Hemoglobin ◽  
Polar Crystal ◽  
Helical Configuration

Highly ordered bundles of deoxyhemoglobin S (HbS) fibers, termed fascicles, are intermediates in the high pH crystallization pathway of HbS. These fibers consist of 7 Wishner-Love double strands in a helical configuration. Since each double strand has a polarity, the odd number of double strands in the fiber imparts a net polarity to the structure. HbS crystals have a unit cell containing two double strands, one of each polarity, resulting in a net polarity of zero. Therefore a rearrangement of the double strands must occur to form a non-polar crystal from the polar fibers. To determine the role of fascicles as an intermediate in the crystallization pathway it is important to understand the relative orientation of fibers within fascicles. Furthermore, an understanding of fascicle structure may have implications for the design of potential sickling inhibitors, since it is bundles of fibers which cause the red cell distortion responsible for the vaso-occlusive complications characteristic of sickle cell anemia.

Energetics and Mechanics of Steep Treadmill Versus Overground Pole Walking: A Pilot Study

2021 ◽  
pp. 1-4
Author(s):  
Nicola Giovanelli ◽  
Lara Mari ◽  
Asia Patini ◽  
Stefano Lazzer
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Vertical Velocity ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Average Intensity ◽  
Rate Of Perceived Exertion ◽  
Spatiotemporal Parameters ◽  
Pole Walking

Purpose: To compare energetics and spatiotemporal parameters of steep uphill pole walking on a treadmill and overground. Methods: First, the authors evaluated 6 male trail runners during an incremental graded test on a treadmill. Then, they performed a maximal overground test with poles and an overground test at 80% (OG80) of vertical velocity of maximal overground test with poles on an uphill mountain path (length = 1.3 km, elevation gain = 433 m). Finally, they covered the same elevation gain using poles on a customized treadmill at the average vertical velocity of the OG80. During all the tests, the authors measured oxygen uptake, carbon dioxide production, heart rate, blood lactate concentration, and rate of perceived exertion. Results: Treadmills required lower metabolic power (15.3 [1.9] vs 16.6 [2.0] W/kg, P = .002) and vertical cost of transport (49.6 [2.7] vs 53.7 [2.1] J/kg·m, P < .001) compared with OG80. Also, oxygen uptake was lower on a treadmill (41.7 [5.0] vs 46.2 [5.0] mL/kg·min, P = .001). Conversely, respiratory quotient was higher on TR80 compared with OG80 (0.98 [0.02] vs 0.89 [0.04], P = .032). In addition, rate of perceived exertion was higher on a treadmill and increased with elevation (P < .001). The authors did not detect any differences in other physiological measurements or in spatiotemporal parameters. Conclusions: Researchers, coaches, and athletes should be aware that steep treadmill pole walking requires lower energy consumption but same heart rate and rate of perceived exertion than overground pole walking at the same average intensity.

scholarly journals Exercise-induced hemolysis in sickle cell anemia: shear sensitivity and erythrocyte dehydration

Blood ◽  
1982 ◽  
Vol 59 (5) ◽  
pp. 1055-1060 ◽  
Author(s):  
OS Platt
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Control Group ◽  
Shear Forces ◽  
Vigorous Exercise ◽  
Shear Rates ◽  
Small Vessels ◽  
Shear Sensitivity ◽  
Chronic Hemolysis ◽  
Exercise Induced

Abstract We describe a steady-state patient with sickle cell anemia (SS disease) who developed sporadic hemoglobinuria, historically related to vigorous exercise. We studied him and four other patients with SS disease and demonstrated exercise-induced hemoglobinemia. To see if SS erythrocytes were abnormally fragile when exposed to shear forces that could be generated in small vessels of exercising muscles, we exposed them to physiologic shear rates in a cone-plate viscometer. We show that SS erythrocytes are more shear sensitive than normal erythrocytes. This phenomenon is directly related to the presence of dehydrated cells as demonstrated by the increasing shear sensitivity of increasingly dehydrated cells separated on Stractan density gradients. Normal shear sensitivity could be restored to dehydrated layers by restoring normal hydration. Restoration of shear stability was complete in all layers except for the most dense ISC layer. A control group of patients with SC disease exhibited no exercise-induced hemoglobinemia, no abnormal shear sensitivity of whole blood, and only rare dehydrated ISCs. These studies suggest that the exercise-induced hemolysis in SS patients is related to the lysis of dehydrated, shear-sensitive cells. This same process may also contribute to the chronic hemolysis of SS disease--a phenomenon known to correlate with the numbers of dehydrated ISCs.

scholarly journals Role of the Spleen and Effect of Splenectomy in Sickle Cell Disease

Blood ◽  
1958 ◽  
Vol 13 (6) ◽  
pp. 569-581 ◽  
Author(s):  
C. C. SPRAGUE ◽  
J. C. S. PATERSON
Keyword(s):  
Sickle Cell Disease ◽  
Adult Patient ◽  
Survival Time ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Cell Disease ◽  
Erythrocyte Survival ◽  
Effect Of Splenectomy ◽  
Hb C

Abstract The survival of sickle cell anemia and sickle-cell/Hb-C erythrocytes was determined by the radioactive chromium method, both in their parent circulations and in the circulations of compatible normal recipients. In sickle cell anemia patients with splenomegaly the average erythrocyte survival time (T½) was found to be 3.7 days. After splenectomy T½ increased to an average of 11.4 days. In sickle cell anemia patients without splenomegaly the average T½ was found to be 10 days. In five instances an average T½ of 9.2 days was found, whereas the average T½ for the same cells in the circulations of normal recipients was 4.4 days. In sickle-cell/Hb-C disease the average T½ was 15.7 days. Following splenectomy in two patients, T½ was unchanged in one and increased in the second. T½ was shortened in two of three instances when these cells were transfused into normal recipients, but the data are insufficient to permit conclusions to be drawn. The role of the spleen in hemolysis is discussed briefly and it is concluded that the hemolytic process in sickle cell anemia is accelerated in the presence of a spleen. This finding is compatible with the diminution in the severity of sickle cell anemia frequently recognized in the adult patient whose spleen has atrophied, and in the child following splenectomy. The validity of the chromate-tagging method for determining erythrocyte survival is discussed. Splenectomy was performed in children in whom the erythrocyte survival was shortened (T½ less than 6 days).

scholarly journals Evidence for Folic Acid Deficiency in the Genesis of Anemic Sickle Cell Crisis

Blood ◽  
1962 ◽  
Vol 20 (1) ◽  
pp. 19-32 ◽  
Author(s):  
LAWRENCE E. PIERCE ◽  
CHARLES E. RATH
Keyword(s):  
Folic Acid ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Acute Infection ◽  
Indirect Evidence ◽  
Chronic Alcoholism ◽  
Limiting Factor ◽  
Folic Acid Deficiency ◽  
Acid Deficiency ◽  
Sickle Cell Crisis

Abstract Two cases are presented of sickle cell anemia demonstrating evidence of folic acid deficiency during a period of anemic crisis. One patient had acute hypoplastic crisis associated with megaloblastic erythropoiesis not in conjunction with acute infection, dietary inadequacy, gastrointestinal malabsorption or chronic alcoholism. An increased excretion of urinary formiminoglutamic acid of 8.8 µM/hr. after histidine stimulation was observed in association with more severe anemia than had been noted previously during nine years observation. Prompt reticulocytosis and rise in hematocrit to previous levels occurred when 1 mg. oral daily folic acid was administered. Improvement was accompanied by a fall in FIGlu excretion to normalcy. Since the observation of folic acid responsiveness in this patient, it has not been necessary to transfuse him for a period in excess of 15 months whereas his previous average requirement approached one unit each month for the past seven and one-half years. A second patient demonstrated increased formiminoglutamicaciduria coincident with anemic sickle cell crisis following bilateral bronchopneumonia with pulmonary thrombosis. There was a beneficial hematologic response to oral folic acid supplementation in physiologic doses. Previously determined control urinary FIGlu levels had been within normal limits. Increased urinary FIGlu has been observed in five additional sickle cell patients not in anemic crisis. One of these (V. K.) was tested for sensitivity to higher dosage levels of folic acid (5 mg. each day) without improvement. Low levels of FIGlu-like material persisted in some patients with sickle cell anemia after treatment with folic acid. Indirect evidence would indicate that this material is urocanic acid and may be related to the chronic liver dysfunction frequently present in sickle cell disease. Evidence has been presented which indicates that folic acid may be a limiting factor in the development of and recovery from anemic sickle cell crisis.

Hemorheological alterations in sickle cell anemia and their clinical consequences – The role of genetic modulators

2017 ◽  
Vol 64 (4) ◽  
pp. 859-866 ◽  
Author(s):  
Marisa Silva ◽  
Sofia Vargas ◽  
Andreia Coelho ◽  
Alexandra Dias ◽  
Teresa Ferreira ◽  
...  
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Clinical Consequences ◽  
Genetic Modulators
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