Reticulocyte response

Addisonian pernicious anemia - Parenteral therapy is required for life oral therapy is not dependable. Administer 100 meg daily for 6 or 7 days by IM or deep subcutaneous injection. If there is clinical improvement and a reticulocyte response, give the same amount on alternate days for 7 doses, then every 3 to 4 days for another 2 to 3 weeks. By this time, hematologic values should have become normal. Follow this regimen with 100 meg monthly for life. Administer folic acid concomitantly if needed. 

Iron therapy is indicated only for the prevention or cure of iron deficiency. In general terms, making 25 mg of iron per day available to the bone marrow will allow an iron deficiency anaemia to respond with a rise of 1% of haemoglobin (0.15 g Hb/100 ml) per day a reticulocyte response occurs between 4 and 12 days. An increase in the haemoglobin of at least 2 g/dl after 3 weeks of therapy is a reasonable criterion of an adequate response. Oral preparations are the treatment of choice for almost all patients due to their effectiveness, safety and low cost. Parenteral preparations should be restricted to the few patients unable to absorb or tolerate oral preparations. Red cell transfusion is necessary only in patients with severe symptomatic rmaemia or where chronic blood loss exceeds the possible rate of oral or parenteral replacement. 

Epoetin (recombinant derived human erythropoietin) must be given s.c. (which may be more effective) or i.v. the t) is 4 h and appears not to be affected by dialysis. Maximum reticulocyte response... 

One patient has been found with this deficiency (All). Hie patient, an infant, was mentally retarded, had a megaloblastic anemia and abnormally high levels of serum and erythrocyte folate. In spite of the high serum folate concentration there was a marked rise in the reticulocyte count when the patient was treated with folate. It was thought that the patient had impaired utilization of -methyltetrahydrofolate. Assay of liver W -methyltetrahy-drofolate transferase showed it to be reduced. It was suggested that folate accumulated at the N -methyltetrahydrofolate block and could therefore not be further utilized. Treatment with pteroylglutamic acid provided a means of producing active folate up to the point of the block. Unfortunately this patient was also treated with pyridoxine, and it is not clear which vitamin was responsible for the reticulocyte response. Further studies are required to determine the precise nature of this metabolic disorder. 

Clinically, the effectiveness of iron therapy is best evaluated by tracking the reticulocyte response and the rise in the Hb or the hematocrit. An increase in the reticulocyte count is not observed for at least 4—7 days after beginning therapy. An increase in the Hb level takes even longer. A decision as to the effectiveness of treatment should not be made until 3—4 weeks after the start of treatment, when an increase in the Hb concentration (2 g/dL is considered a positive response, assuming that no other change in the patient s clinical status can account for the improvement and that the patient has not been transfused. 

In humans, the two principal methods used for assaying the intrinsic factor are the reticulocyte response after administration of the intrinsic factor to pernicious anemia patients, and studies of the effect of intrinsic factor on urinary or fecal excretion, on hepatic uptake, on blood plasma radioactivity, and total body radioactivity after the administration of labeled vitamin B12. 

Although they are not well understood, the changes that take place in cells other than erythrocytes in iron deficiency may be significant in the pathogenesis of iron deficiency. For example, the reticulocyte response to iron administration is delayed in iron deficiency anemia. This delay is believed to result from injuries to the red cell precursors. The defects of the precursors are reflected by lower levels of RNA and DNA syn-... 

Wallerstein et al. (1953b) found a severe biochemical deficiency of ascorbic acid in pernicious anemia. They followed reticulocyte responses to Bi2 or folic acid without, and then with, ascorbic acid. They concluded that ascorbic acid may play an adjuvant role in hemopoiesis, probably by enhancing the production of citrovorum factor. 

In the clinical assay of a preparation, the increase in reticulocytes is often looked upon as proof of activity. However, there is frequently a lack of correlation between the degree of reticulocyte response and the rapidity of increase of red blood cells. A good reticulocyte response usually, but not invariably foretells a good erj throcyte increase. On the other hand, a poor reticulocyte response is often followed by a satisfactory increase in erythrocytes. For this reason, less attention is paid, at present, to the reticulocyte rise as a measure of the effectiveness of a tested material. Observation of the magnitude of the reticulocyte rise gives merely an indication of presence of potency of a given material, but not of degree of potency. 

They followed the course of the active principle by noting the presence or absence of a reticulocyte response after the administration of an extract to a pernicious anemia patient during relapse. At first, the material was given orally, but later in the work, it was administered intravenously. In case of negative clinical results, the responsiveness of the patient was tested with liver or liver extracts of proved potency. 

This and all subsequent fractions have been compare the very different procedures involved, maximal reticulocyte response, though injected though given over a period of six days. 

This acetone-ether-insoluble portion when administered to four patients in a daily amoimt of 3.4 mg. in addition to 6.4 mg. of the previously mentioned accessory factors, gave on the 10th day an average erythrocyte response of from 1.8 million R.B.C. per cmm. to 2.5 million R.B.C. per cmm. with appropriate reticulocyte response (62). 

Dr. Benjamin Alexander of the Beth Israel Hospital in Boston, Massachusetts also gave this fraction to a patient in a daily amount of 0.4 mg. without the addition of accessory factors. The initial R.B.C. level was 1.0 million per cmm. A maximum reticulocyte response of 12.4% was obtained on the 6th day and on the 8th day the R.B.C. was found to be 1.6 million per cmm. (personal communication). 

This permutite filtrate was also tested by Dr. Benjamin Alexander in a patient with an initial R.B.C. level of 1.4 million. In a daily dosage of 0.035 mg., without accessory factors added, a maximum reticulocyte response of 11.4% was obtained on the 6th day and the final R.B.C. level of 1.9 million was reached on the 10th day (personal communication). The isolation of the active fraction is summarized in Table XVII. 

An obvious objection to their conclusion is that if they divorce from the pernicious-anemia curing factor the ability to elicit a reticulocyte response, it is difficult to explain the reticulocyte increase which does occur in the treatment of pernicious anemia patients with such preparations as those to which they attribute only that factor. It is also doubtful whether a normal person can be used to test for any component of the antianemic principle. 

The first case, with a recent history of pernicious anemia, was pven injections intravenously for fifteen days, followed by no improvement in blood count, although a moderate reticulocyte response accompanied by a feeling of well-being was observed. Subsequent oral treatment with liver extract effected satisfactory results. 

In their second case, one which had previously responded well to both arsenic and liver, Cuthbertson and associates observed that on subcutaneous injection of the amino acids, the clinical condition of the patient became worse. However, after a transfusion, liver therapy produced favorable results. Although tryptophan and histidine produced an early small reticulocyte response in both cases, there was no appreciable increase in the hemoglobin or red cell levels. Thus, even though there are indications that they have some stimulating action on hematopoietic tissue, the results do not justify ascribing the activity of liver to its content of free tryptophane and histidine. Dominici and Penati (27) were also unable to confirm the favorable results of the French authors. 

Peabody and Neale (94) stated that histidine and tryptophane are probably not the constituents of liver extract which are effective in eliciting a reticulocyte response in grain-fed pigeons. Since they believed that the pigeon response is a measure of the substance or substances active in the treatment of pernicious anemia, they concluded that liver extracts do not owe their antianemic potency to these amino acids. Inasmuch as the only reliable test for pernicious anemia potency is a clinical one, their conclusion cannot be accepted without reservations. 

Although it proved inactive in two other cases, intramuscular administration of heparin in one case effected an erythrocyte response, from an initial level of 2.6 millions to 3.9 millions in a four week period. There was no indication of a reticulocyte response at any time during treatment. As Aleksandrowicz and Gabryelski admit, the therapeutic value of anti-prothrombin is not supported by this single case. 

In 1936, Wilkinson (126) applied Reinecke acid precipitation as employed by Dakin and West to the preparation of active liver extracts, (124, 125, 127). He compared the clinical activity of his liver product with those prepared according to the 1935 method of Dakin and West and that of Laland, Klem, Strandell, ci al. Dakin and West s material showed maximal reticulocyte response with a dose of 58 to 120 mg. administered intramuscularly. With preparations similar to those used by the Scandinavian workers, Wilkinson obtained maximal response with a total dose of 40 to 80 mg. (68). With his own product, Wilkinson was able to elicit maximal response with total doses of 18 to 36 mg., representing an original amount of 661 to 1332 g. of fresh liver. 

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