bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyploidization of Megakaryocytes in Normal Humans, in Patients with Idiopathic Thrombocytopenia and with Pernicious Anaemia
Authors: Queisser U. , Queisser W. , Spiertz B. 
Published: March 2008

Summary. Polyploidization of human megakaryocytes was studied in bone marrow aspirates from three normal individuals, three patients with idiopathic thrombocytopenic purpura (ITP) and three patients with pernicious anaemia (PA). The cells were labelled in vitro with tritiated thymidine and analysed by a combined cytophotometric and autoradiographic method. Cells were divided into types I, II and III.Normal megakaryocytes showed ploidy stages from 4c to 32c, the 4c stage occurring only in type I. The labelling indices showed that in normal megakaryocytes polyploidization takes place in type I and II and not in type III cells. This study provided evidence for alternation of DNA synthesis and rest periods. It is postulated that rhythmical polyploidization in megakaryocytopoiesis takes place. The progressive increase in the proportion of cells in successive resting periods (G‐phases) suggests that high ploidy cells have longer resting periods than low ploidy cells.In ITP, megakaryocyte morphology, labelling indices and distribution of DNA content were normal. Assuming a normal ploidy composition in ITP, the megakaryocytic hyperplasia observed in typical cases may be explained by an increased influx from the unrecognizable progenitor cell.In PA, an arrest of megakaryocytic DNA synthesis was observed comparable to that found in megaloblastic erythropoiesis.
Deduction of Mean Red‐Cell Life‐Span from 51Cr Survival Curves*
Authors: Garby L. , Mollison P. L. 
Published: March 2008

Summary. Twenty‐two estimates of Cr red‐cell survival in normal subjects, using the ‘citrate‐wash’ method of labelling, are described; results obtained with this method are shown to have given closely similar results in three different laboratories. By contrast, methods in which 51Cr is added to ACD blood have given a much wider range of normal values.In 14 patients red‐cell survival was estimated simultaneously with DF32P and 51Cr, the latter results being corrected for Cr elution using empirical factors. Estimates of mean red‐cell life‐span by the two methods agreed fairly closely. It is concluded that when 51Cr is used as a red‐cell label, the citrate‐wash method, or some other method which has also been shown to give reproducible results in different laboratories, should be used and the results should then be corrected so as to obtain an estimate of mean life‐span. Such estimates should be more useful in clinical practice than uncorrected Cr survival data.
The Effects of Phenothiazines on Human Erythrocytes: An Ultrastructural Study
Authors: Preston F. E. , Lee D. 
Published: March 2008

Summary. The in vitro effects of two phenothiazine derivatives on human erythrocytes have been studied by scanning electron microscopy.The induced changes were identical for both compounds and consisted of cup‐shaped deformities of the erythrocytes, sphering and membrane defects. The type and degree of alteration was a function of the concentration of the phenothiazine derivative.The demonstration of multiple surface membrane defects affords a satisfactory explanation of the haemolysis of red cells which have been exposed to chlorpromazine concentrations greater than 2.5 × 10−4m.
Re‐assessment of the Reliability of the Haematocrit
Authors: England J. M. , Walford D. M. , Waters D. A. W. 
Published: March 2008

Summary. Significant quantities of plasma are trapped between the centrifuged red cells in the microhaematocrit. This produces a falsely high haematocrit and mean corpuscular volume, and a falsely low mean corpuscular haemoglobin concentration. Trapped plasma accounts for approximately 3% of the normal red‐cell column. Slightly higher values are found in macrocytic anaemias, but values as high as 5–6% may be found in the hypochromic anaemias, and even over 20% in sickled samples of blood.It is suggested that automatic blood counters of the Coulter S type be set to record a true haematocrit without trapped plasma. This value is 1 1/2% less than the microhaematocrit value with normal blood. Absolute values in normal subjects under these conditions are reported.
The Prevalence of Iron Deficient Erythropoiesis and Anaemia in a Rural Jamaican Community
Authors: Ahern E. J. , Swan A. V. , Ahern V. N. 
Published: March 2008

SummarySerum iron, iron binding capacity and transferrin saturation were measured in 389 predominantly Negro adults from an agricultural community in Jamaica. The relationships between iron measurements and several other red cell characteristics were investigated and the possible influence of common inherited red cell defects was examined. Iron deficient erythropoiesis (transferrin saturation ± 15%) occurred in only a third of anaemic subjects. Values for total iron binding capacity were considerably lower than those found in a large random sample from Wales (Jacobs et al., 1969). These findings are considered in relation to the nutritional status of the population.
Heterogeneous Metabolism of Marrow Ferritins during Erythroid Cell Maturation
Authors: Shepp M. , Toff H. , Yamada H. , Gabuzda T. G. 
Published: March 2008

SummaryTwo metabolically distinct pools of ferritin exist side by side in the bone marrow. One has been designated‘anabolic’ since it accepts iron from transferrin and is presumably an isoferritin characteristic of erythroid cells. The other is primarily‘catabolic’, since it accepts iron from degraded haemoglobin and is considered an isoferritin of reticuloendothelial cells. Both of these isoferritins, however, incorporate iron during the period of erythroid cell maturation in the marrow, although the incorporation proceeds at markedly different rates. The incorporation of iron into both isoferritins can be demonstrated regardless of the route of administration of iron, i.e., whether by transferrin or by degraded haemoglobin. The results support the hypothesis that storage iron moves directly or indirectly from the ferritin pool of the developing erythroid cell to that of the reticuloendothelial cell. They also show that reticulothelial cell ferritin iron undergoes rapid reutilization to re‐enter the iron storage pool of erythroblasts.
The Relation between Erythropoiesis and Plasma Erythropoietin Levels in Normal and Genetically Anaemic Mice during Prolonged Hypoxia or after Whole‐Body Irradiation
Authors: Russell Elizabeth S. , Keighley Geoffrey 
Published: March 2008

SummaryWhen normal mice (B6D2F1, WBB6F1‐ +/+ and WCB6F1‐ +/+) are exposed to constant hypoxia, they respond with a steady increase of PCV for about 3 weeks. Plasma erythropoietin increases sharply for the first 1 or 2 days only, then falls to control levels, with occasional temporary increases through the next 30–40 days. Genetically anaemic mice (WBB6F1‐W/Wv and WCB6F1‐Sl/Sld) respond differently. The W/W mice show an increase of PCV, and Sl/Sld mice do not, but both respond with large increases of plasma erythropoietin levels which persist, except for some temporary falls, through 16–40 days. The response to hypoxia of chimeric W/W mice, their anaemia cured by implantation of +/+ marrow cells, resembles that of normal +/+ mice much more than that of anaemic W/W mice. Although normal WBB6F1‐ +/+ mice recover after 200 R whole‐body irradiation at rates similar to those of other normal mice, anaemic WBB6F1‐W/W mice show delayed onset of haemopoietic recovery in spite of significant production of erythropoietin. Exogenous erythropoietin injected into mice disappears more slowly from the plasma of anaemic W/W mice than from the plasma of normal +/+ mice, and erythropoietin which has been passed through WBB6F1‐ +/+ normal mice is not thereby made as effective in anaemic W/W mice as it is in normal mice. These findings are consistent with the view that although both W/W and Sl/Sld anaemic mice can produce large amounts of erythropoietin over prolonged periods, W/W mice remain anaemic because of a genetic defect in RBC precursors, and Sl/Sld mice remain anaemic because of a genetic defect in some part of the internal environment in which the RBC must develop.WBB6F1‐W/W anaemic mice, when exposed to hypoxia, excrete erythropoietin in their urine. When these mice have their kidneys removed and they are exposed to hypoxia for a short time there is no significant production of erythropoietin.The suggestion is made that some genetically anaemic large domestic animals, if they could be found, might be useful and needed sources of erythropoietin.
Urokinase Therapy: Dosage Schedules and Coagulant Side Effects
Authors: Prentice C. R. M. , Turpie A. G. G. , McNicol G. P. , Douglas A. S. 
Published: March 2008

SummaryThe effect of a new preparation of urokinase (Roche) has been studied, in the laboratory and in 10 patients and three volunteers. It is a non‐toxic and active fibrinolytic agent if given in adequate dosage, but it was found that a small initial infusion gave rise to a paradoxical coagulant effect in the recipient. This effect was associated with the formation of‘cryofibrinogen’ and an increase in factor‐VIII activity. The coagulant effect was probably mediated by a low‐grade process of plasminogen activation rather than due to the preparation of urokinase itself. The preparation did have minor intrinsic thromboplastic activity similar to that described in other preparations of urokinase, but it is unlikely that this would produce a significant effect in vivo. The coagulant effect could be overcome by increasing the initial dose of urokinase to produce rapidly the haemostatic defect normally associated with fibrinolytic therapy.
Effect of Vincristine on Platelet Production in Mice
Authors: Rak K. 
Published: March 2008

SummaryPlatelet production was investigated using [75Se]selenomethionine bio‐assay in C57BL mice after a single injection of vincristine within the dose range 0.2–3.2 mg/kg. The changes in the circulating platelet count were also followed. There was an immediate, not strictly dose‐dependent, fall in the number of platelets, a quick recovery with an overshoot after small doses, delayed recovery with a moderate overshoot after intermediate doses and a slow recovery returning to normal levels after large doses. The drug caused an overproduction of platelets with every dose used, but this was not necessarily reflected in the peripheral platelet count. It seems unlikely, at least after the smaller doses, that the early fall in platelets plays a role in the increased platelet production. Platelet precursors are resistant to a single dose of vincristine and the drug may have a primary stimulatory effect on the megakaryocytopoietic system.
Comparative Effects of Fibrinogen Degradation Fragments D and E on Coagulation
Authors: Larrieu M. J. , Rigollot C. , Marder V. J. 
Published: March 2008

SummaryThe mechanism of anticoagulant action of the fibrinogen degradation products (fragments D and E) has been investigated using purified products in selected esterolytic, proteolytic and coagulation systems. Their modes of action were distinctly different. Fragment D acted primarily by inhibiting fibrin monomer polymerization, while fragment E did not significantly alter this process. The latter product appeared to be a competitive inhibitor of the clotting action of thrombin on fibrinogen. Its comparative effect in thrombin proteolytic and esterolytic systems indicated that fragment E did not irreversibly inactivate the enzyme centre of thrombin. Rather, it appeared to block a thrombin binding site essential for proper alignment with the fibrinogen substrate. This competitive inhibition suggests that fragment E may derive from and share physical structures with the thrombin‐susceptible, N‐terminal portion of the fibrinogen molecule.
The Metabolism of Maturing Reticulocytes
Authors: Gasko O. , Danon D. 
Published: March 2008

SummaryThe aerobic metabolism of populations of rabbit reticulocytes separated into age groups by differential flotation was measured by manometric techniques. The activity of the Krebs tricarboxylic acid cycle was studied by following the metabolism of substrates such as [2‐14C]acetate, [3‐14C]pyruvate and [6‐14C]glucose. These mitochondrial activities were found to decline with maturation of the reticulocytes. The mode of decline was studied and its significance is discussed.
The Iron Content of Intestinal Epithelial Cells and Its Subcellular Distribution: Studies on Normal, Iron‐Overloaded and Iron‐Deficient Rats
Authors: Richmond Veronica S. , Worwood Mark , Jacobs Allan 
Published: March 2008

Summary. Small intestinal epithelial cells from normal, iron‐loaded and iron‐deficient rats were homogenized and fractionated by differential centrifugation. The iron content of the fractions was measured together with the activities of two iron containing enzymes, succinic dehydrogenase and cytochrome oxidase. A comparison of the values obtained from the iron‐overloaded rats with controls showed no significant increase in either the iron content or the enzyme activities. However, the iron‐deficient rats showed a marked decrease in both. In all three cases the concentration of iron was particularly high in the mitochondrial fraction. In irondeficient epithelial cells mitochondrial enzyme activity appeared in the soluble fraction suggesting mitochondrial damage.It is suggested that body iron is reflected by mitochondrial iron status and function in the intestinal epithelial cells and that this is a factor determining cell uptake of iron from the gut lumen.
Identification of a New Vitamin B12 Binder (Transcobalamin III) in Normal Human Serum
Authors: Bloomfield F. J. , Scott J. M. 
Published: March 2008

Summary. Fractionation of vitamin B12 binders in a normal human serum pool showed a distribution of 92% Transcobalamin II (TCII) and 8% Transcobalamin I (TCI) on DEAE‐cellulose chromatography. Separation of the same serum pool using gel filtration gave 74% TCII and 26% TCI. This 18% discrepancy could be due either to massive contamination of the DEAE‐cellulose TCII peak with TCI, or to the presence of a high molecular weight binder which elutes with TCII on DEAE‐cellulose, and with TCI on gel filtration.Refractionation of the TCII peak showed it to be relatively uncontaminated with TCI. Removal of the low molecular weight binders with charcoal consistently gave a peak in the TCII area on DEAE, which subsequent gel filtration analysis showed to be of high molecular weight. This new binder is further distinguished from TCI by the observation that its vitamin B12 binding capacity does not increase to the same extent as TCI on fasting.Since this binder could be demonstrated in 50 different normal sera, it is clearly not a pathological binder, and should be called Transcobalamin III (TCIII).
The in Vitro Action of Dapsone and its Derivatives on Normal and G6PD‐deficient Red Cells
Authors: Scott G. L. , Rasbridge Marian R. 
Published: March 2008

Summary. In an attempt to define the mechanism of dapsone‐induced haemolysis the in vitro action of dapsone (4,4′, diaminodiphenylsulphone) and some of its derivatives on normal and G6PD‐deficient red cells has been investigated. Dapsone, its N′ acetyl‐ and hydroxy‐derivatives have no measurable effect on metabolism, haemoglobin or the membrane in either normal or G6PD‐deficient red cells. 4, hydroxylamino‐4′ aminodiphenylsulphone (HADS) and 4, hydroxylamino‐4′ acetaminodiphenylsulphone (HMDS) have oxidant effects on red cells. Both of these compounds readily form methaemoglobin but in normal red cells higher levels of methaemoglobin are achieved with HMDS than with HADS. With both compounds less methaemoglobin is formed in glucose‐deprived or in G6PD‐deficient red cells. In normal red cells hexose monophosphate pathway (HMP) activity is increased, HADS being a more potent stimulus than HMDS. It is suggested that methaemoglobin formation is dependent upon the recycling of these compounds via the HMP.Normal red cells incubated with the two hydroxylamine compounds did not show any change in reduced glutathione (GSH), globin or the membrane, apart from increased sensitivity to peroxide lysis. G6PD‐deficient red cells, on the other hand, did lose GSH rapidly and underwent increased autohaemolysis. The mechanism of these effects is discussed.Some, but not all, of the in vivo effects of dapsone can be reproduced by the hydroxylamine derivatives in vitro. It is concluded that either some other derivatives are involved or that the effect of long exposure to these oxidant compounds in vivo is different.
Perturbation of Generation Cycle of Human Leukaemic Lymphoblasts in Vivo by l‐Asparaginase
Authors: Ernst Peter 
Published: March 2008

Summary. In four patients with acute lymphoblastic leukaemia the cytokinetic effect on leukaemic lymphoblasts of l‐asparaginase has been studied in vivo, by a method of combined autoradiography and microspectrophotometry. During an observation period of 30 hr the labelling index, the mitotic index and the mean grain count decreased, and in one case studied a rapid decline in the peripheral blast cell count occurred. The interpretation of the observations is that l‐asparaginase arrests cells in S phase, whereas no preferential effect is exerted on cells in G1 and mitosis. Besides this action l‐asparaginase has a generalized lytic effect on lymphoblasts independent of proliferative activity. Differentiated myeloid and erythroid cells seem to be resistant to the action of l‐asparaginase.In the study a microspectrophotometric method by which it is possible to measure in the autoradiograms the DNA content of single cells labelled with 3H‐nucleoside without interference from the autoradiographic silver grains is described.
Isoprecipitins: Precipitating Antibodies Reacting with Blood Group Specific Substances
Authors: Pintera J. , Vacl J. 
Published: March 2008

Summary.A precipitating iso‐anti‐A was discovered in the serum of a female blood donor when routine tests were being performed for anti‐Au HAA antibody by means of counter‐immunoelectrophoresis. The isoprecipitin reacted with the sera of blood group A and AB donors and with dilute solutions of blood group A substance. Using the same technique, a significantly higher instance of anti‐A and anti‐B isoprecipitins was found in mothers of children suffering from haemolytic disease of the newborn due to ABO incompatibility. Regular screening of antenatal sera for precipitating anti‐A and anti‐B is recommended for possible antenatal prediction of affected infants. False positive reactions might be obtained when known Au HAA antigen‐positive sera used for screening for the presence of human anti‐Au HAA also contain A or B specific substances which could react with corresponding precipitating antibodies.
125I‐Transferrin Turnover in Rabbits with Haemolytic Anaemia
Authors: Shepp Margaret , Yamada Hideo , Berenfeld Marion , Gabuzda Thomas G. 
Published: March 2008

Summary.The metabolism of purified 125I‐labelled homologous transferrin in rabbits with haemolytic anaemia was compared to that in control rabbits and no significant differences were found. During 3 weeks of haemolysis plasma transferrin concentrations did not change appreciably. The fractional turnover rate was 43% of the intravascular pool per day. The intravascular pool was 45% of the total exchangeable transferrin.
The Separation of Free and Bound Vitamin B12
Authors: Adams J. F. , Mcewan Fiona C. 
Published: March 2008

Summary. The separation of free and bound vitamin B12 was studied using four binders and two forms of vitamin B12 and effecting separation by charcoal adsorption, bag dialysis, ultrafiltration and gel filtration. In charcoal separation systems the results could be significantly affected by a change in the binder, the form of vitamin B12, the type of charcoal, the mass of charcoal or the presence of albumin. In systems with gastric juice and cyanocobalamin one charcoal separation procedure yielded results which were comparable to those obtained by all other procedures but this did not occur with gastric juice and hydroxocobalamin or with other binders and both forms of vitamin B12.Results obtained using dialysis for separation varied with the membrane employed. Results obtained by gel filtration were significantly different from those obtained by ultrafiltration and those obtained by one ultrafiltration procedure were always significantly different from those yielded by another. Separation methods which give insignificantly different results in one system do not necessarily yield insignificantly different results in a system with a different binder or different form of vitamin B12.
The Role of Complement in Endotoxin Shock and Disseminated Intravascular Coagulation: Experimental Observations in the Dog
Authors: Garner R. , Chater B. V. , Brown D. L. 
Published: March 2008

Summary.The endotoxin shock response of Beagle dogs, characterized by profound hypotension and progressive fatal disseminated intravascular coagulation (DIC) was compared in anaesthetized normal dogs and in dogs previously decomplemented with purified cobra venom factor. The hypotension and the early thrombocytopenia were abolished in the decomplemented group, while the subsequent DIC was greatly ameliorated. Factor VII was apparently activated in decomplemented dogs but consumed in normal dogs. An observation as yet to be defined in relation to the shock syndrome was that dog platelets lost their collagen aggregation throughout the period of total decomplementation. It is suggested that complement activation is a major requirement for the full expression of fatally progressive DIC in endotoxin shock and that the activation of the coagulation system occurs, at least in part, via the extrinsic pathway.
Globin Synthesis in the Jamaican Negro with Beta‐Thalassaemia
Authors: Friedman Sh. , Schwartz E. , Ahern V. , Ahern E. 
Published: March 2008

Summary. Globin synthesis was studied in three Jamaican Negro families with 18 heterozygotes and five homozygotes for β‐thalassaemia. Synthesis of the β‐chain of Hb A in the peripheral blood of heterozygotes was equal to that of α‐chain in 10 patients and was decreased in the remainder. In one patient with Hb C β‐thalassaemia, the β/α ratio was normal. These findings were similar to those in American Negroes, but differed from those in Caucasians with β‐thalassaemia trait, in each of whom the β/α ratio was decreased. Globin synthesis was balanced in the bone marrows of Negro and Caucasian heterozygotes. Despite the milder clinical disease in Negro homozygotes as compared to Caucasian patients, the β/α synthesis ratios were similar in both groups.The presence of α‐thalassaemia combined with β‐thalassaemia in Negro heterezygotes is not a likely explanation for the high incidence of balanced globin synthesis ratios. The expression of relative β‐ to α‐chain synthesis in Negro heterozygotes appears to be modified by a factor which is not linked to the δ‐chain locus. The nature of this factor is not known at present.