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Hematological anomalies have been observed in patients with prolonged liver damage. For example, patients with chronic cirrhosis (scarring of the liver) often develop anemia and other blood disorders. Hemoglobin is the metalloprotein within red blood cells that is responsible for the oxygen-carrying capacity of blood, and its function may be affected by liver damage. The poor prognosis of patients with cirrhosis and anemia has stimulated further study of hemoglobin function and oxygen saturation.Blood samples from both cirrhotic patients and healthy individuals at rest and after exercise were exposed to varying partial pressures of oxygen. Measurement of oxyhemoglobin dissociation curves (ODCs [Figure 1]) from the blood samples revealed significant functional differences in the hemoglobin from cirrhotic patients relative to control subjects.
Figure 1 Oxyhemoglobin dissociation curve for cirrhotic patients (CP) at rest and for healthy controls (HC) at rest and after 20 minutes of exerciseVitamins are considered nontoxic supplements and are frequently provided to anemic patients to increase red blood cell production. They may therefore have therapeutic benefits for cirrhotic patients. However, some studies indicate that excessive vitamin consumption may lead to oxidative stress that could induce anemia through hemolysis (red blood cell rupturing) . Hemoglobin strongly absorbs light at 577 nm, and researchers conducted hemolysis assays by spinning down red blood cells and measuring absorbance (Abs) of the supernatant at 577 nm to determine how much hemoglobin was released. The assay was carried out in the presence of four vitamins to determine their potential as oxidizing agents, and results are shown in Table 1.Table 1 Hemolysis of Red Blood Cells from Healthy Donors Treated With Vitamins [2 mM] for 30 Minutes, Measured by Absorbance at 577 nm
Adapted from Clerbaux T, Detry B, Geubel A, et al. The oxyhemoglobin dissociation curve in liver cirrhosis. Chest. 2006;129(2) :438-45.
-The effect of anaerobic exercise on the oxygen saturation curve in healthy patients is shown in Figure 1. Which of the following is involved in the change in the oxygen dissociation curve?

Question

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Hematological anomalies have been observed in patients with prolonged liver damage. For example, patients with chronic cirrhosis (scarring of the liver) often develop anemia and other blood disorders. Hemoglobin is the metalloprotein within red blood cells that is responsible for the oxygen-carrying capacity of blood, and its function may be affected by liver damage. The poor prognosis of patients with cirrhosis and anemia has stimulated further study of hemoglobin function and oxygen saturation.Blood samples from both cirrhotic patients and healthy individuals at rest and after exercise were exposed to varying partial pressures of oxygen. Measurement of oxyhemoglobin dissociation curves (ODCs [Figure 1]) from the blood samples revealed significant functional differences in the hemoglobin from cirrhotic patients relative to control subjects.

Figure 1 Oxyhemoglobin dissociation curve for cirrhotic patients (CP) at rest and for healthy controls (HC) at rest and after 20 minutes of exerciseVitamins are considered nontoxic supplements and are frequently provided to anemic patients to increase red blood cell production. They may therefore have therapeutic benefits for cirrhotic patients. However, some studies indicate that excessive vitamin consumption may lead to oxidative stress that could induce anemia through hemolysis (red blood cell rupturing) . Hemoglobin strongly absorbs light at 577 nm, and researchers conducted hemolysis assays by spinning down red blood cells and measuring absorbance (Abs) of the supernatant at 577 nm to determine how much hemoglobin was released. The assay was carried out in the presence of four vitamins to determine their potential as oxidizing agents, and results are shown in Table 1.Table 1 Hemolysis of Red Blood Cells from Healthy Donors Treated With Vitamins [2 mM] for 30 Minutes, Measured by Absorbance at 577 nm

Adapted from Clerbaux T, Detry B, Geubel A, et al. The oxyhemoglobin dissociation curve in liver cirrhosis. Chest. 2006;129(2) :438-45.
-The effect of anaerobic exercise on the oxygen saturation curve in healthy patients is shown in Figure 1. Which of the following is involved in the change in the oxygen dissociation curve?

Quizplus · Accepted Answer

11ecba2d_0f58_b925_a3bf_5d9f114e9ebc_MD0008_00 For muscles to contract during exercise, they must break down glucose for energy. This process requires the continuous reduction of NAD⁺ to NADH as glucose is oxidized to pyruvate. Cells must oxidize NADH back to NAD⁺ to continue glycolysis. Under anaerobic conditions this is accomplished by coupling oxidation of NADH to the reduction of pyruvate, producing lactic acid. 11ecba2d_0f58_e036_a3bf_7be538f28598_MD0008_00 NADH+pyruvate ⇌NAD++lactic acid During the 20 minutes of exercise performed by healthy individuals, increased lactic acid production causes an increase in the H⁺ concentration, which lowers the blood pH. Accumulated H⁺ ions are able to bind to hemoglobin and reduce its affinity for oxygen in a phenomenon known as the Bohr effect. This reduced affinity appears as a right shift in the ODC, as shown in Figure 1. The reduction in hemoglobin affinity for oxygen allows more O₂ to be unloaded to the muscle cells. Therefore, the need for more oxygen in contracting muscles is met as by-products generated during exercise decrease hemoglobin oxygen binding. (Choice A) CO₂ production is increased, not decreased, in contracting muscles. Like lactic acid buildup, this process also contributes to hemoglobin's reduced affinity for oxygen. (Choice B) Exercise does indeed decrease the partial pressure of oxygen in muscles as oxygen is consumed. However, changes in oxygen partial pressure correspond to different positions along the ODC, not to changes in its shape. (Choice C) Hemoglobin binds oxygen less tightly during exercise due to a decrease in blood pH. Educational objective: Acidic byproducts of glycolysis produced during exercise cause a right shift in the hemoglobin oxygen dissociation curve. This phenomenon, known as the Bohr effect, provides muscles with a means to receive more oxygen from the blood during activity.

Passage Hematological Anomalies Have Been Observed in Patients with Prolonged Liver