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A study has been undertaken to determine the rate at which stored platelets lose their ability to respond to stimuli and to establish whether this decrease in function could be ascribed to the storage-induced proteolysis of prominent platelet proteins observed by others. Platelet concentrates were stored at 4°C and 25°C for up to 14 days, and their ability to secrete and aggregate in response to appropriate stimuli was determined at 6, 96, and 192 hr after venipuncture. At each time point the protein complement of the platelets was also monitored by SDS-polyacrylamide gel electrophoresis to assess the extent of intracellular protein degradation. Platelets from concentrates stored at either temperature exhibited a decreased ability to respond to stimuli as storage time increased. After 8 days of storage at 4°C and up to 9 days at 25°C, no proteolysis of major platelet proteins was observed; however, complete loss of platelet function was observed. This strongly indicates that a decrease in platelet function should not be causally linked to degraded contractile-structural proteins and that extending the functional life of platelets during storage is still an attainable goal since proteolysis is notthe inevitable result of short-term storage.

1. Six animals (cats) were subjected to four whole body irradiation exposures over a period of one and one-half years. Irradiation dosage was 200 r to the whole body, an amount producing severe hematopoietic abnormalities in the cat. Irradiation in each case was immediately preceded by a large phlebotomy, so that functional impairment of erythropoiesis resulting from irradiation could be assessed in terms of a defective regeneration of erythrocytes. The effect of multiple radiation exposures could also be evaluated for each animal in terms of its prior response to phlebotomy and irradiation. The effects of repeated exposures on the leukocytes could likewise be assessed by means of the comparative leukocyte regeneration curves. 2. Little evidence of permanent functional damage of erythropoietic tissue by repeated exposures under the conditions of this experiment were observed. Erythrocyte and hemoglobin regeneration patterns were very similar from one exposure to another. However, hemoglobin regeneration was slightly slower after the fourth and last irradiation. Whether this represents encroachment on marrow reserve by multiple irradiations or whether it was an artifact resulting from iron deficiency cannot be said with certainty. Multiple exposures exerted little apparent effect on the leukocyte regeneration curves. 3. After recovery from the fourth irradiation, the percentage of mononuclear leukocytes was somewhat less than that prior to the first. 4. It is concluded that while repeated irradiation insults under the conditions of our experiment probably result in hidden damage even in the presence of apparent complete recovery, this damage is so subtle that it is difficult to detect by the tests of marrow reserve employed in this study.

The literature concerning blood histamine has been reviewed, including the evidence that the incorporation of histamine within the myeloid leukocytes may be one of the metabolic functions of myelopoiesis. Data are presented on the histamine content of blood in normal subjects and in subjects with acute leukemia, chronic myelocytic leukemia, erythremia, and with leukocytoses or leukemoid reactions of other etiologies. The changing relationships of total blood histamine to unit myeloid cell histamine in subjects receiving irradiation therapy for chronic myelocytic leukemia are also presented. The data indicate that total blood histamine in chronic myelocytic leukemia is usually very high in comparison to normal, that the values in erythremia show a definite but less marked tendency in the same direction, while the values in leukocytoses of other etiology are, with few exceptions, normal or low. The blood histamine per million myeloid cells is, on the average, about twice normal in subjects with chronic myelocytic leukemia, within the normal range or a little low in erythremia, and very low on the average in the group of leukocytoses studied. The suggestion is tentatively made that an aberration in this metabolic process (histamine incorporation within myeloid leukocytes) may be an inherent component of chronic myelocytic leukemia, whereas in physiologic leukocytoses and leukemoid reactions this is not the case.

1. Lymphocytes in dogs have been labeled by means of the DNA-P32 incorporation technic. 2. In the thoracic duct, a high level of lymphocyte DNA-P32 specific activity is reached within two hours. After 24 to 30 hours, the activity falls to a lower level which is then maintained for at least 160 hours. 3. Lymphocyte-granulocyte separations on the blood revealed that DNA-P32 specific activity reached a peak on the fourth day for both lymphocytes and granulocytes. 4. These findings are consistent with a short maturation time for the lymphocyte and a short intravascular time.

Recent concepts of the relationship of the blood granulocyte mass to the marrow reserve of granulocytes have been reviewed. Evidence has been presented to show that the marrow is the chief area of granulocyte "reserves" or "stores." The development of acute leukocytosis in response to a stimulus such as the intravenous injection of bacterial endotoxin depends upon release of cells from the intramedullary pool of granulocytes. The turnover of the marrow granulocyte reserve (MGR) is an orderly process in the steady state, and determines the form of the curve of DNA-labeled granulocytes in the peripheral blood. From estimates of the turnover time of the MGR it appears that the granulocyte spends an average time of about 10 hours in the peripheral blood. Granulocytes do not appear to recirculate once they have left the peripheral blood and have entered the tissues. However, granulocytes may be sequestered within capillary beds for variable periods, and may re-enter the circulating blood from such areas. Such cells are not to be considered as having re-entered the blood from the tissues. The intravenous injection of a purified bacterial lipopolysaccharide as a stimulus to acute leukocytosis is described. The possbile usefulness of this procedure in assessing the MGR is discussed.

Data are presented correlating 22 determinations of the histamine content of blood in patients with chronic granulocytic leukemia with (1) the basophils (2) the other myeloid granulocytes. Expressing the histamine in each case on the basis of the amount in 108 granulocytes, there is a readily evident positive correlation with the basophil percentage and a negative correlation with the percentage of other myeloid elements. This is strikingly apparent in instances where blood with a very high percentage of basophils was analyzed. The data indicate that in chronic granulocytic leukemia, the basophil is predominantly and, perhaps exclusively, responsible for the marked elevations in blood histamine. Inferentially, it appears probable that this cell type, though small in numbers, may be the principal carrier of histamine in non-leukemic blood.

A standard method of concentrating urinary erythropoietin and a standard assay procedure can be used to demonstrate the hormone in the urine of normal human beings. The eythropoietically active material recovered produced increasing response to increasing dose and was completely neutralized by rabbit serum containing antibodies to human urinary erythropoietin. The average normal man excretes approximately 1 standard A unit of erythropoietin per day and the average normal woman excretes approximately 0.4 units per day. With the exception of one patient with a renal allograft, and normal subjects living at extremely high altitude, the recovery of erythropoietin from the urine has not been found to exceed normal in patients with polycythemia, whether the polycythemia is primary or secondary to renal pathology. Markedly elevated levels of erythropoietin were found in subjects living at extremely high altitude.

1. Two cases of hemophilia are presented in whom the development of a circulating anticoagulant was detected. This anticoagulant was demonstrated in the whole blood, plasma, and serum of both patients. 2. Both patients became refractory to treatment with either fresh whole blood, plasma, or antihemophilic globulin (Fraction I of Cohn). In fact, the anticoagulant apparently made its appearance as a result of repeated transfusions or injections of antihemophilic globulin. 3. The anticoagulant in each case was shown not to inhibit any of the elements participating in the classical theory of clotting, i.e., prothrombin, thromboplastin, thrombin or fibrinogen. It was also demonstrated that this anticoagulant was not related to heparin in its mechanism of action. 4. Electrophoretic fractionation of the plasma was carried out, and it was found that the anticoagulant was associated with the gamma globulin fraction of plasma. 5. The demonstration of specific precipitin titres in the serum of each of these patients against antihemophilic globulin seemed to indicate that the mechanism of action of the anticoagulant was to inhibit the action of antihemophilic globulin. This was further substantiated by the in vitro inhibition of the ability of antihemophilic globulin to accelerate the coagulation time of ordinary hemophilic blood. 6. A hypothesis is presented to explain the appearance of the anticoagulant. It is believed that these two hemophiliacs are deficient in or lack antihemophilic globulin in their blood, and hence repeated injections of the globulin either in the form of whole blood, plasma, or Fraction I of Cohn results in "isoimmunization" against the injected globulin. The resulting antibodies inhibit any antihemophilic globulin which may then be injected and hence explain the refractory state exhibited by these two cases. Blood from these patients containing these antibodies likewise exerts an anticoagulant influence when added to normal blood by the same mechanism. 7. A discussion of the implications of this phenomenon in the development of a refractory phase in hemophilia is presented.

Patients with severe hematologic disorders may have elevated erythropoietin titers in plasma or urine at higher hemoglobin concentrations than those associated with elevated titers in experimental animals or patients anemic as a result of simple blood loss. Patients with "primary" hematologic disease may have a measurable titer of erythropoietin in the plasma and urine at hemoglobin concentrations up to 8 Gm./100 ml., but patients with iron-deficiency anemia show elevated titers in the urine only with hemoglobin concentrations at or below 4 Gm./100 ml. and in the plasma below 5 Gm./100 ml. The abruptness with which the titer rises and the severity of the anemia required before measurable titers appear are similar in man and in rabbits, sheep and dogs. The fact that no measurable erythropoietin titer can be demonstrated when the hemoglobin concentration is well below that required for intense stimulation of erythropoiesis and the abruptness of the rise at hemoglobin concentration of 4 Gm./100 ml. or less suggest that erythropoietin may not be an important factor in the control of erythropoiesis except in extreme circumstances. On the other hand, these facts may be explained more simply by the insensitivity of the assay methods used.

1. Leukocyte homogenates show active, reproducible respiratory activity in a fortified system. 2. Chloramphenicol inhibits leukocyte respiration in vitro when used in concentrations similar to other commonly used inhibitors. 3. Chlortetracycline, oxytetracycline, penicillin and streptomycin have no significant effect on leukocyte respiration. 4. Urethane and atabrine produce inhibition of leukocyte respiration, but the latter is more active. 5. The possible sites of action of chloramphenicol in cellular metabolism are discussed.

Since anemia or polycythemia can result only from a change in rate of formation of red cells or a change in the life span of the red cells, a determination of the total red cell volume, Fe59 studies to estimate the rate and site of production of red cells, and C14-labeled glycine or Fe59 studies to determine the life span of red cells permit a description of the pathogenesis of any alterations in the erythropoietic state. This has been of great value in clinical hematology from the stand-point of understanding the basic nature of the various diseases and, in particular, the selection of patients with unusual anemias possibly related to hypersplenism who might benefit from splenectomy. Splenic erythropoiesis can be easily differentiated from splenic red cell destruction. Since two of these methods—the determination of the blood volume and the Fe59 studies—are now possible in general commumnity hospitals and since modifications of the Fe59 method permit the determination of the life span of the red cell, adequate evaluation of the erythropoietic state is now possible in general hospitals.

A woman with a history of thrombocytopenic purpura occurring approximately every twenty-eight days was studied extensively on the Metabolic Research Ward. The patient had been treated previously with splenectomy and hystero-oophorectomy without improvement. The cyclical nature of her thrombocytopenia was documented by repeated hematologic observations. Endocrinologic studies demonstrated no evidence of ovarian activity or cyclical variations in adrenal activity. Urinary gonadotropins (FSH) fell coincident with the fall in platelets and suggest that cyclical pituitary function might be related in some way. The exact etiologic mechanisms, however, were not disclosed by this study.

A family of Greek derivation is described in which 2 out of 6 children examined exhibited a sickle cell type of anemia. The father of these children was found to have thalassemia minor and the mother the sickle cell trait. It is presumed that the anemia in the two children was due to simultaneous heterozygosity for the sickling and thalassemia genes. Biochemical studies with reference to the occurrence and amounts of normal, sickle cell, and fetal hemoglobin were carried out on the parents and the 6 children. The theoretic interpretation of the biochemical findings is discussed.

1. The general aim of the investigations here reported has been to obtain evidence for or against "indirect" radiation effects. 2. To this end, twenty-six successful cross circulation experiments (carotid to carotid anastomoses) have been performed between normal cats and radiated cats. 3. Cross circulation was established in most instances at some specified time interval after the radiation of one partner. All intervals up to eighty-two hours after radiation of one partner were covered. 4. In seven experiments cross circulation was established and then one animal radiated while the other was shielded. These were considered the most critical experiments of the group. 5. Detailed data on leukocyte and lymphocyte counts in the normal animals obtained during an approximately twenty-eight day period of follow-up are presented. 6. These data are not considered to support the thesis of indirect effects peculiar to radiation. A trend toward slightly lowered absolute lymphocyte counts in normal animals after cross circulation was not considered significant, and in no instance did leukopenia develop in the normal animal. 7. The literature is reviewed and discussed.

The hormonal control through the hypophyseo-adrenal cortical system of lymphoid tissue structure and function is an important concept. We cannot at the present time regard that the concept is established fact. Final judgment must await additional work and the clarification of some of the inconsistencies which appear to exist. It seems reasonable that lymphoid tissue is one of the end organs of adrenal cortical hormone and that it may perhaps play a role in the response of the organism to stress. It seems quite clear that the sugar hormone of the adrenal cortex is capable of producing structural alterations in lymphoid tissue. Change in thoracic duct lymphocyte numbers as a result of augmentation in the amount of available adrenal cortical hormone is at present controversial. Experiments in this laboratory have failed to demonstrate it. The production of lymphopenia, at least in some species and possibly in man, by increasing available sugar hormone is supported by some evidence. The exact mechanism of production of lymphopenia is open to question, its relationship to changes in lymphoid tissue structure being one of inference. The converse situation—absolute lympocytosis resulting from deprivation of adrenal cortical hormone—is the subject of controversial reports. At best, it must be admitted that relatively slight alterations from the accepted normal range of lymphocyte values occur in the adrenal insufficient organism. Changes in plasma gamma globulins and antibody titers associated with changes in the amount of available cortical hormone are reported. It should be clarified whether such changes have necessarily resulted from lymphocyte dissolution or are related to other of the variegated actions of adrenal cortical hormone. The relationship of adrenal cortical hormone to lymphoid tissue and lymphocytes and the relationship of the latter to the response of the organism to stress must indeed be complex. It is reasonably well established that the life span of the lymphocyte is very short indeed1,58,22 and each lymphocyte presumably liberates its metabolically important contents within a few hours at the most. If stress continues for any period of time, as often it does, it is difficult to visualize the wisdom of interfering with the production of metabolically vital substances in order to secure the transient benefits of lymphoid tissue dissolution. It is also somewhat difficult to regard as proved that the various changes reported after hormone augmentation or deprivation necessarily represent the normal mechanism by which these factors are regulated and kept within physiologic limits. More investigations are required to answer such questions and to further elucidate the interrelationship of the adrenal cortex and lymphoid tissues.