losartan-potassium and Methemoglobinemia

Absolute polycythemia is a condition with increased red blood cell mass. There are a number of primary and secondary polycythemic disorders leading to absolute polycythemia. Primary polycythemias are caused by a defect intrinsic to the erythroid progenitor cells. The best characterized primary polycythemia is the autosomal dominant primary familial and congenital polycythemia (PFCP). Familial or childhood occurrence of the myeloproliferative disorder polycythemia vera are also discussed, emphasizing the importance of distinction between polycythemia vera and PFCP. Congenital or familial secondary polycythemic conditions are characterized by increased red cell mass, which is caused by circulating serum factors, typically erythropoietin.

Topics: 2,3-Diphosphoglycerate; Adult; Bisphosphoglycerate Mutase; Child; Erythropoietin; Hemoglobins, Abnormal; Humans; Methemoglobinemia; Polycythemia

Lisa Capaldini, a physician who treats patients with HIV-related fatigue, discusses symptoms, diagnosis techniques, and treatments of depression, anemia, and various other roots of fatigue in HIV-positive patients. Biochemical depression, caused by abnormal levels of serotonin and norepinephrine in the brain, is easily misdiagnosed or overlooked. Physical and emotional symptoms of depression mirror common effects of HIV such as exhaustion, anger, and irritability. Knowing the history of depression prior to HIV infection, including previous drug abuse and family history of depression, will help to diagnose fatigue. Dr. Capaldini recommends antidepressants provided the condition is properly diagnosed and the side effects are not harmful to the patient. Selective serotonin reuptake inhibitors (SSRI), the most frequently prescribed antidepressants, can cause short term sexual dysfunction. Bupropion and Wellbutrin can be prescribed to avoid this side effect. Psychotherapy can be effective if therapists are familiar with HIV disease and can distinguish between symptoms brought on by behavior, addictive habits, or pre-existing depression. Consideration also must be given to drug interactions, particularly with the antiretrovirals ritonavir and delavirdine, which can cause seizures or disturb cardiac rhythm. Anemia is most noticeable after physical exertion, and symptoms are more evident based on the increased rate that red blood cells move out of the normal range. To determine the course of treatment, physicians need to clarify the cause of anemia. Anemia can be caused by drugs, vitamin deficiencies, or other nutritional problems. Adrenal insufficiency, methemoglobinemia, and malnutrition are also causes of fatigue. Diagnosing fatigue due to hepatitis B or C, rather than HIV, can be achieved by measuring hepatitis levels and observing T cell counts and viral load. Dr. Capaldini suggests that proper diet and exercise prevent fatigue from getting worse.

Topics: Adrenal Insufficiency; Anemia; Anti-HIV Agents; Antidepressive Agents; Depression; Drug Interactions; Erythropoietin; Fatigue; Female; Hepatitis, Viral, Human; HIV Infections; Humans; Male; Methemoglobinemia; Nutrition Disorders

Acute hypoxemia was produced in chronically catheterized sheep fetuses to determine the response time necessary to increase plasma immunoreactive erythropoietin (Ep) concentration. Sodium nitrite (0.2 mM) was infused via a fetal vein to induce fetal hypoxemia. The resultant fetal methemoglobinemia was associated with a predictable, incremental decrease in arterial oxygen content. Twelve nitrite infusions were performed in eight fetal sheep preparations (gestational ages 115-146 days). Mean methemoglobin level increased to 33% of total Hb after 1-2 h of NaNO2 infusion. These results were compared to those obtained in nine control studies in eight fetuses in which no change was observed for plasma Ep, arterial oxygen content, PaO2, pHa, or whole blood lactate. In the nitrite infused group, however, a significant and progressive increase in mean plasma Ep level over baseline levels was observed during the 4th and 5th h of hypoxemia (p less than 0.01). This change in Ep was significantly greater compared to the control group. These results, however, were confounded by the concomitant development of a lactic acidemia secondary to the fetal hypoxemia. To examine the theoretic possibility that lactic acidemia may primarily affect fetal Ep levels, an additional group of five fetuses was infused with L-lactic acid for the same time period. Although the decrements in pHa and whole blood lactate levels achieved in these fetuses were in excess of those observed during the nitrite infusions, this possibility was ruled out since no change in fetal plasma Ep levels occurred. We conclude that during the 4th h of acute fetal hypoxemia a predictable, progressive increase in plasma Ep level is observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acidosis; Animals; Erythropoietin; Female; Fetal Blood; Fetal Hypoxia; Hemodynamics; Lactates; Lactic Acid; Methemoglobinemia; Oxygen; Pregnancy; Radioimmunoassay; Sheep; Sodium Nitrite