bluuebunny/crossref_metadata_2025_split huggingface dataset:
Megakaryocytopoiesis in Splenectomized and ‘Hypersplenic’ Rats
Authors: Rolovic Zoran , Baldini Mario 
Published: March 2008

Summary. Megakaryocytopoiesis was studied in splenectomized, in normal and in ‘hypersplenic’ rats in order to evaluate the role of the spleen on platelet kinetics. Bone marrow autoradiography after injection of tritiated thymidine was utilized in this investigation. The splenectomized rats were studied 6 weeks after the operation when their platelet count was stable at a level of 23% higher than before splenectomy. Splenomegaly was produced by repeated intraperitoneal injections of methylcellulose and was associated with a 52% lowering of the platelet count.The results revealed identical patterns of megakaryocytopoiesis in splenectomized and normal rats indicating that post‐splenectomy thrombocy tosis was not the consequence of an increased rate of megakaryocyte maturation. On the contrary, megakaryocytopoiesis in the ‘hypersplenic’ rats was stimulated, although slightly so. This demonstrated that thrombocytopenia in the rats with splenomegaly could not be ascribed to the functional inhibition of megakaryocyte maturation.These findings support the view that in normal conditions the role of the spleen lies only in the distribution of the circulating platelet mass with a higher concentration of platelets in the spleen, and are consistent with the suggestion that in ‘hyper‐splenism’ the thrombocytopenia occurs because of excessive pooling of the platelets in the enlarged spleen, while the bone marrow provides a larger than normal number of platelets.
Intestinal Absorption of Reduced Folate Compounds in Man
Authors: Perry Janet , Chanarin I. 
Published: March 2008

Summary. Oral administration of folate compounds was followed by a rise in L. casei active factors in blood. This was due to reduction and methylation of the folate compounds in the small gut and this was demonstrated by the use of dihydropteroylglutamic acid labelled with tritium.Parenteral administration of tritium‐labelled folate analogues was followed by a rapid exchange with unlabelled L. casei active folate from tissues.
The Haemoglobin Constitution of Infants with the Haemoglobin Bart's Hydrops Foetalis Syndrome
Authors: Weatherall D. J. , Clegg J. B. , Boon Wong Hock 
Published: March 2008

Summary. The haemoglobin constitution of 14 infants with the haemoglobin Bart's hydrops syndrome has been examined. Thirteen of the infants were stillborn or lived only a few minutes after delivery, but in one case an exchange transfusion was performed and the pattern of globin chain synthesis examined by an [H3]leucine incorporation experiment utilizing umbilical cord blood. These studies indicate that the syndrome results from a total deficiency of α‐chain production. Furthermore, it has been possible to exclude the presence of fragments of α‐chain longer than II residues in the cells of these infants.In each infant a small quantity of haemoglobin was found which consisted of normal γ‐chains in association with chains of unique constitution. A similar component was found in trace amounts in normal umbilical cord blood. This haemoglobin may be identical with haemoglobin Portland. It is suggested that the non‐γ‐chain of this haemoglobin is the product of a normal foetal haemoglobin locus which produces very small amounts of gene product in normal infants but which is capable of increased activity in the presence of a partial or total deficiency of α‐chains.
Platelet Glycolytic Enzymes: Effect of Cellular Disruption Procedures on Activity
Authors: Doery J. C. G. , Hirsh J. , Gruchy G. C. de 
Published: March 2008

Summary The activities and cellular distribution of the following glycolytic enzymes were determined in human platelets: hexokinase, phosphoglucose isomerase, phosphofructokinase, aldolase, triosephosphate isomerase, glyceraldehyde 3‐phosphate dehydrogenase, 3‐phosphoglycerate kinase, phosphoglyceromutase, enolase, pyruvate kinase, lactate dehydrogenase and glucose 6‐phosphate dehydrogenase and 6‐phosphogluconate dehydrogenase.The effect of four different methods of cellular disruption on platelet ultrastructure and enzyme activity was determined. Freezing and thawing was found to inactivate phosphofructokinase markedly, and to inactivate hexokinase and glucose‐6‐phosphate dehydrogenase slightly. In addition, glucose‐6‐phosphate dehydrogenase was rapidly inactivated in cell lysates irrespective of the method of lysis. This process, which was considerably greater at room temperature than 4°C, was prevented by addition of 0.2 mM‐NADP to the medium before disruption of the platelets. Spontaneous loss of activity of phosphofructokinase, triosephosphate isomerase and pyruvate kinase in cell lysates was decreased by the presence of the reducing agent, dithiothreitol.Hexokinase was found in both the soluble and particulate fraction. The proportions of the enzyme distributed between these two fractions depended on the disruption procedure used.
The Relationship between Serum Iron Levels and Ascorbic Acid Stores in Siderotic Bantu
Authors: Wapnick A. A. , Bothwell T. H. , Seftel H. 
Published: March 2008

Summary The concentrations of serum iron and of leucocyte ascorbic acid were measured in 35 adult Bantu subjects and were compared with the marrow gradings of storage iron. Ascorbic acid depletion was almost uniformly present in the 18 subjects with increased iron stores, but was uncommon in those with normal stores. On the other hand, there was no significant correlation between the serum iron levels and the marrow iron gradings.After therapy for 7 days with ascorbic acid the mean serum iron level rose significantly in the siderotic group but was unchanged in the group with normal stores. At this time there was a highly significant correlation between the levels of serum iron and the marrow iron gradings.It is concluded that the serum iron can be used as an index of iron overload in the Bantu only after repletion with ascorbic acid.
The Role of Slowly Proliferating Cells in Rat Bone Marrow during. Regeneration following Hydroxyurea
Authors: Bohne F. , Haas R. J. , Fliedner T. M. , Fache I. 
Published: March 2008

Summary. Rats were labelled with 3H‐thymidine (3H‐TdR) in utero and for 6 weeks after birth to obtain 100% labelling of all the cells in the animals. 6 weeks after the last 3H‐TdR injection only cytokinetically resting cells were still labelled. In bone marrow these were cells of the bone marrow matrix and a fraction of small bone marrow lymphocytes. At this time the effect of hydroxyurea (HU) on bone marrow and especially on the resting cells of this organ was studied.Animals which had received 4x 500 mg HU/kg at 6 hr intervals showed a destruction of all proliferating cells of the bone marrow. Regeneration started 4 days after HU‐treatment and was not completed before 10 days afterwards. The resting matrix cells did not change in number or labelling intensity which shows that they were neither destroyed nor stimulated to proliferate during regeneration. In contrast, the resting small bone marrow lymphocytes showed a dilution of labelling intensity, and after an initial increase, a decrease of their number during recovery of bone marrow. At the same time a new class of labelled cells which was identified as undifferentiated blast cells appeared, and later on labelled erythroid and myeloid precursor cells could be observed. The labelling of these cells disappeared c 6 days after HU‐treatment. Animals which received a single injection of the total dose of 2000 mg/HU/kg showed essentially the same effects but a markedly smaller response to the drug.
Platelet Volume: Density Relationships in Normal and Acutely Bled Dogs
Authors: Minter F. M. , Ingram M. 
Published: March 2008

Summary.The relationship between platelet volume and platelet density was studied in normal dogs and in dogs subjected to acute blood loss.Frequency distribution histograms of platelet densities were obtained by centrifuging diluted whole blood over a series of 13 silicone solutions varying in specific gravity from 1.007 to 1.065 and determining the percentage of platelets that remained in the supernatants above the silicone after centrifugation for 2 min at 9500 g. Frequency distribution histograms of platelet volumes were obtained using the Model B Coulter Counter with the Coulter Model H particle size analyser.Platelets of normal dogs have a skewed distribution of densities. The mean density is approximately 1.020 but the plateau region on the cumulative distribution of platelet densities is not reached until specific gravity 1.045‐1.050. Mean platelet volume increases as density increases.When platelet production was increased following acute blood loss, both mean density and mean volume increased abruptly, but the change in density histograms was more prolonged as well as more striking than change in mean density. Results of serial observations suggest that the large dense platelets produced following acute blood loss represent an aberrant population and that these platelets do not decrease in volume as they age.
A New Technique for the Quantitative Estimation of Fibrinolysis using In Vivo [125I]Fibrinogen
Authors: Hickman J. A. 
Published: March 2008

Summary.A technique for the quantitative measurement of the fibrinolytic activity of blood is described, based on the rate of release of radioactivity in vitro from clotted blood obtained from patients previously receiving [125I]fibrinogen. The accuracy of the technique was assessed by comparison of the release of radioactivity with the appearance of fibrin degradation products, by observation of the effects of fibrinolytic inhibitors and by comparison of the initial fibrin content of the clot with the measurement of radioactivity released after total lysis.The measurement of fibrinolysis with this technique correlated well with the dilute blood clot lysis time in samples with a normal fibrinogen concentration, but the correlation was poor when the fibrinogen concentration was elevated. Since the measurement of fibrinolysis by this new technique is likely to be largely unaffected by the fibrinogen concentration, it is suggested that this technique is of particular value when the fibrinogen concentration is outside the normal range and, further, will allow significant comparison of fibrinolytic activity between blood samples of differing fibrinogen concentration.
Studies on the Regulation of Granulopoiesis
Authors: Morley A. , Monette F. C. , Rizzoli V. , Howard D. , Stohlman F. 
Published: March 2008

Summary.Tritiated thymidine autoradiography was used to study the control of granulocyte production and release using the irradiated leg shielded mouse as an experimental model. Neutropenia resulted in a shortening of 24–36 hr in the mean transit time through the non‐proliferating granulocyte compartment. There was little difference between neutropenic and control animals in labelling indices of the cells in the proliferative granulocyte compartments, which suggests that the granulocytic hyperplasia observed in the neutropenic mice was predominantly due to differentiation of morphologically unrecognizable precursor cells rather than increased proliferation of morphologically recognizable cells. The persistence of a labelling index of approximately 60% in the myeloblast‐promyelocyte compartment 24 hr after injection suggests that these precursor cells were rapidly proliferating.
Prothrombal: A New Concentrate of Human Prothrombin Complex for Clinical Use
Authors: Bruning P. F. , Loeliger E. A. 
Published: March 2008

Summary. There is a great need for a concentrate containing coagulation factors II, VII, IX and X, suitable for the prevention or treatment of haemorrhage due to a deficiency of these factors. This paper describes a routine method for the production of such a concentrate (called Prothrombal), the properties of the material and its clinical use. The method has the following advantages: simplicity, suitability for small‐scale application in any blood bank, and the use of standard human ACD plasma as starting material, the other components of the blood remaining available for clinical use. In the adsorption‐elution procedure aluminum hydroxide was a suitable adsorbent.Administration of Prothrombal to patients was tolerated very well. Safe haemostasis was obtained in a patient with severe haemophilia B using Prothrombal to cover several extensive orthopaedic operations. The recovery in vivo of coagulation factor activity was satisfactory and reliable and was assessed for factor IX at about 25%. The results of giving Prothrombal on nine occasions to patients with a severe deficiency of factor IX (haemophilia B), factor II, factor VII, or a combination of factors II, VII, IX and X, are described and discussed.
Apparent Folate Deficiency in Iron‐Deficiency Anaemia
Authors: Roberts P. D. , StJohn D. J. B. , Sinha R. , Stewart J. S. , Baird I. M. , Coghill N. F. , Morgan J. O. 
Published: March 2008

Summary. Examination of 50 patients with iron‐deficient hypochromic anaemia showed evidence suggesting a high incidence of folate depletion. The peripheral blood films of 44 patients (88%) showed more than 3% of neutrophils with five nuclear lobes, 35 patients (70%) had a high mean neutrophil lobe count, 20 patients (40%) had hypersegmented neutrophils and 19 patients (38%) had giant metamyelocytes in the bone marrow. The serum folate was below 3 ng/ml in 12 patients and 3–6 ng/ml in 18. Red‐cell folate was subnormal in 15%, and 45% had a positive Figlu test.Correlation between various tests for folate deficiency was not found, apart from a correlation between red‐cell folate levels and morphological changes in the neutrophils. The haemoglobin rise following intravenous iron therapy was smaller when the serum folate level was low. There was probably a similar relationship to the red‐cell folate level, but the numbers tested were small. The presence of neutrophil multilobing in the peripheral blood film and giant metamyelocytes in the bone marrow did not influence the response to iron therapy, neither did an abnormal Figlu excretion.Following intravenous iron therapy, both neutrophil multilobing and marrow giant metamyelocytes were significantly reduced in number. This therapy did not significantly alter Figlu excretion measured 6 weeks after treatment, but both serum and red‐cell folate levels fell. Intravenous iron therapy did not produce any significant changes in the serum vitamin B12 levels. The part that iron deficiency itself may play in causing apparent folate depletion is discussed.
Epsilon‐Aminocaproic Acid Therapy for Dental Extractions in Haemophilia and Christmas Disease: A Double Blind Controlled Trial
Authors: Walsh P. N. , Rizza C. R. , Matthews J. M. , Eipe J. , Kernoff P. B. A. , Coles M. D. , Bloom A. L. , Kaufman B. M. , Beck P. , Hanan C. M. , Biggs Rosemary 
Published: March 2008

Summary. The results are reported of a pilot study and two separate double blind controlled trials of the effectiveness of epsilon‐aminocaproic acid (EACA) in dental extractions in patients with haemophilia and Christmas disease. In the major trial 31 patients were studied; 23 at Oxford and eight at Cardiff. All patients received either EACA (6 g four times daily for 10 days at Oxford or for 7 days at Cardiff) or a placebo, in conjunction with a single preoperative dose of therapeutic materials expected to raise the plasma factor‐VIII or factor‐IX level to 50%. Post‐operative therapeutic materials were withheld unless intraoral bleeding occurred. Despite the fact that plasma factor‐VIII or factor‐IX levels were, on average, lower, the number of teeth extracted larger, the amount of therapeutic concentrates less and the postinfusion plasma factor‐VIII or factor‐IX levels lower in the EACA group at Oxford, the incidence of postoperative intraoral bleeding was lower and the requirements for postoperative therapeutic materials less in the group treated with EACA. Side‐effects were not a major problem. The number of patients studied at Cardiff was too few for statistical analysis but the results were similar to those at Oxford. The total conservation of therapeutic materials at Oxford in comparison to the amount utilized before EACA was used is estimated on the basis of these results to be approximately 12 000 factor‐VIII or factor‐IX units/patient, or approximately 190 units/kg/patient, equivalent, for each patient, to the amount derived from approximately 120 blood donations.These results show that EACA in conjunction with preoperative therapeutic concentrates sufficient to raise the plasma factor‐VIII or factor‐IX level to 50% can be useful for all patients with haemophilia and Christmas disease undergoing tooth extraction. In some patients EACA therapy is contraindicated and for these patients adequate cover with therapeutic materials must be provided during the postoperative period.
Detection of Splenic Anti‐Platelet Antibody Synthesis in Idiopathic Autoimmune Thrombocytopenic Purpura (ATP)
Authors: Karpatkin S. , Strick N. , Siskind G. W. 
Published: March 2008

Summary. A significant decline in the serum anti‐platelet antibody titre, as measured by the platelet factor 3 (PF‐3) immuno‐injury technique, followed splenectomy in seven out of eight patients with autoimmune thrombocytopenic purpura (ATP).Anti‐platelet antibody could be eluted from the splenic extracts of 11 of 13 patients with ATP. The anti‐platelet antibody detected could be adsorbed with washed human platelets and could be removed with rabbit anti‐human IgG (RAHIgG). Extracts of spleens from six ‘control’ patients (five with hereditary spherocytosis and one with Milroy's disease) had no detectable anti‐platelet antibody.Minced spleen from nine patients with ATP and five ‘controls’ were cultured for 17 hr in a medium containing 14C amino acids. Washed platelets adsorbed at least five times more Ladioactivity from globulin fractions of cultured ATP spleens than did ‘control’ spleens. In contrast, washed granulocytes failed to adsorb significant radioactivity. Supernatants obtained from these splenic incubates were also tested for anti‐platelet antibody (PF‐3 test). Anti‐platelet antibody was detectable in all seven ATP patients tested and was absent in the three control subjects tested. The anti‐platelet antibody could be adsorbed with washed human platelets but not with washed human granulocytes or red blood cells. These data suggest that the spleen might be a significant site for anti‐platelet antibody synthesis in ATP.
Normal Haematological Values in the Central American Population
Authors: Viteri F. E. , de Tuna V. , Guzmán M. A. 
Published: March 2008

Summary. A total of 6787 subjects were studied, representative of the Central American populations but without clinical evidence of haematological disease. Out of this sample, 452 individuals fulfilled the following conditions: they were hook‐worm free, with values of serum iron > 50 μg/100 ml; saturation of transferrin > 20%; serum folates (L. casei) > 5 ng/ml; and serum vitamin B12 (E. gracilis) > 150 Pg/ml. These individuals were considered adequately nourished from the erythropoietic point of view, and they constituted the ‘normal’ sample from which values for haemoglobin, packed cell volume, red blood cell count, and red blood cell indices were calculated. These subjects were grouped by age and sex, and according to the altitude above sea level of their place of residence (0‐750 and 751–1500 m).Results from this highly selected sample indicate that haematological values are equal or higher to those reported for ‘normal’ individuals from well‐nourished, non‐tropical populations. To our knowledge, this is the only study where norms have been derived from a population sample with well‐documented ‘normal’ serum values for iron, % saturation of transferrin, folate and vitamin B12.From these data, haematological values below which the risk for an individual having a subnormal haematological state increase, are derived and discussed.
The Function of the Phagocytic Leucocytes in Leukaemia
Authors: Goldman J. M. , Catovsky D. 
Published: March 2008

Summary. Various aspects of the function of the phagocytic cells (neutrophils and monocytes) in the peripheral blood of patients with leukaemia have been reviewed. Mobilization of neutrophils and monocytes to sites of experimentally induced inflammatory lesions appears to be defective in acute myeloid leukaemia (AML). Phagocytosis (uptake of bacteria) appears to be defective in the neutrophils of patients with untreated chronic granulocytic leukaemia. The killing of Candida albicans by neutrophils from patients with AML also seems to be impaired. Preliminary evidence suggests that monocytes from patients with acute monocytic leukaemia have an enhanced phagocytic and candidacidal activity after 7 days in culture.Neutrophils and monocytes from patients with AML do not differ from normal leucocytes in their capacity to reduce nitroblue tetrazolium which suggests that cellular metabolism after phagocytosis is not greatly disordered in leukaemic cells: however, a possible deficiency in the neutrophils in chronic granulocytic leukaemia is suggested. On the other hand, some leukaemic neutrophils lack the enzyme myeloperoxidase and this abnormality is particularly associated with the myeloblastic‐promyelocytic type of AML. The contribution of these leucocyte abnormalities to the pathogenesis of infection is discussed.
Transferrin—Reticulocyte Binding: Evidence for the Functional Importance of Transferrin Conformation
Authors: Lane R. S. 
Published: March 2008

SummaryIron‐free and 59Fe‐labelled human and rabbit 125I‐transferrins have been chromatographed on DEAE cellulose at pH 7.9 and have also been incubated with rabbit reticulocytes in order to determine transferrin and iron uptake.Chromatography of human apo‐ and iron‐transferrin indicated clear differences in their surface properties which are considered to be conformation‐dependent. These differences were not evident in rabbit transferrin samples.Human and rabbit iron‐transferrins and rabbit apo‐transferrin all associated rapidly with rabbit reticulocytes; human apo‐transferrin was only weakly bound. Correlation of data from both experiments suggested that reticulocyte binding of human apo‐transferrin is limited by its molecular confirmation. The incubation studies confirmed results of other workers and indicated that the data from these experiments with human and rabbit transferrin are not in conflict.Compared with rabbit iron‐transferrin, only half as much human iron‐transferrin was bound to rabbit reticulocytes in a comparable experiment. Iron transfer from bound human and rabbit transferrin took place at equal rate. It is argued that fewer receptors on rabbit reticulocytes are available for human transferrin because, when bound, the size and shape of a molecule limits further binding of transferrin molecules at adjacent sites.
The Anaemia of Kala Azar
Authors: Woodruff A. W. , Topley Elizabeth , Knight R. , Downie Campbell G. B. 
Published: March 2008

SummaryIt has been confirmed that during the active phase of kala azar the erythrocyte life span is shortened. At this time patients’ immunoconglutinin titres are raised, and their erythrocytes have been shown to be agglutinated by anti‐complement and anti‐non‐y‐globulin sera. Erythrocyte destruction in kala azar takes place largely in the spleen, as demonstrated by rising counts over the spleen relative to the praecordium and liver following labelling of the patients’ erythrocytes with 51Cr. This point is supported by the absence of anaemia observed in a patient with a heavy kala azar infection but whose spleen had been removed a year earlier. We postulate that an autoimmune mechanism is likely to be the explanation of these observations and of the reduced erythrocyte survival in kala azar. Such a mechanism provides a basis which may help to explain the development of anaemia in a number of other protozoal and helminthic infections in man.