bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platelet Economy (Platelet Survival and Turnover)*
Authors: Mustard J. F. , Rowsell H. C. , Murphy E. A. 
Published: March 2008

Investigators studying blood platelet survival and turnover have used the term ‘thrombo‐kinetics’ to describe the subject, by analogy with the usages of thermodynamics. Inasmuch as these phenomena reflect the interactions and hazards which the platelets encounter while discharging their function in the circulation, we prefer the term ‘platelet economy’ and we consider that the function and fate of the platelet cannot usefully be separated as objects of study.A number of beliefs about platelet function and economy are widely held. First, the platelets play a leading role in haemostasis, a function which is discharged mainly when injury to the vessel wall occurs; their second main function is considered to be in coagulation, which they support or may even initiate. Beyond these, the platelets are thought to have little useful function. The platelet in vivo is commonly supposed to be a fragile structure, irreversibly damaged by aggregation. Some consider it to have a finite life span, determined by exhaustion of its inner reserves, while others consider its life span to be determined by the demands of the body without regard to the age of the individual platelet.We shall present evidence suggesting that some of these views are gross over‐simplifications and some are erroneous.
A Notional Structure for the Rhesus Antigens
Authors: Knox E. G. 
Published: March 2008

The increasing complexity of the Rhesus antigen–antibody reactions is testing the notation systems at present in use, but some of the difficulties are semantic. The Cc/Dd/Ee notation is applied both to genes and to antigens, and this may cause confusion if the two usages are not clearly recognized and distinguished. In particular, our concepts of antigen structure must not be restricted to the linear arrangement implicit in the gene notation. This paper is an attempt to infer a notional structure for the Rhesus antigens without this conceptual restriction.The problem arises from a previous study (Murray, Knox and Walker, 1965) in which it was shown:(a) that in a cde/cde (rr) mother, a foetus with the cDE/cde (R2r) genotype is a more potent D‐sensitizing stimulus than a CDe/cde (R1r) foetus, and
(b) that cDE/cde (R2r) infants with haemolytic disease of the newborn are more severely affected than CDe/cde (R1r) infants. As in the sensitizing mechanism, cDE/cde (R2r) seems to be a more powerful antigen than CDe/cde (R1r).There is also evidence from serological studies that red cells of different genotypes have irregular antigenic strengths, even with respect to factors which genetically are in the same dose. Three main effects have been demonstrated.(a) Dosage effects. A genotype homozygous for a particular factor produces more antigen than does the heterozygote. However, there are quantitative irregularities and the antigenic strengths in homozygotes and heterozygotes are seldom in a 2:1 or any other constant ratio.(b) Cis‐ and trans‐effects. These effects are interactions between different pairs of factors. For example the presence of C‐antigen diminishes the amount of D‐antigen compared with that found when C is replaced by c. When the C and D genes are on the same chromosome this is known as a cis‐effect and when on opposite chromosomes a trans‐effect.(c) Combined antigens. The most important are the anti‐Ce, ‐ce, series of antigen‐antibody reactions. Their special peculiarity is that they are found only when the two components are determined by the same chromosome and not when the genes are carried on opposite chromosomes.
A Histochemical Method for the Demonstration of Leucocyte Naphthylamidase Using Two Substrates: Alanyl‐ and Methionyl‐4‐Methoxy‐2‐Naphthylamide
Authors: Rutenburg A. M. , Rosales C. L. 
Published: March 2008

Histochemical methods for the demonstration of naphthylamidase* in tissues were based on the coupling properties of 2‐naphthylamine (Burstone and Folk, 1956; Nachlas, Crawford and Seligman, 1957) after enzymatic release from amino acid naphthylamides. But significant diffusion of the amine and the lack of a suitable diazonium salt to achieve a sufficiently prompt capture reaction to form an insoluble dye as well as prolonged incubation prevented adequate histochemical localization. When the coupling rate of 2‐naphthylamine was found to be significantly enhanced by the presence of a methoxy group in the 4‐position (Nachlas, Goldstein, Rosenblatt, Kirsch and Seligman, 1959), l‐leucyl‐4‐methoxy‐2‐naphthylamide (Rosenblatt, Nachlas and Seligman, 1958) was synthesized and found to serve as a more satisfactory substrate for naphthylamidase demonstration (Nachlas, Morris, Rosenblatt and Seligman, 1960).Replacement of the leucyl group in leucyl‐2‐naphthylamide by alanyl or methionyl groups resulted in a more rapid hydrolysis by naphthylamidase (Nachlas, Goldstein and Seligman, 1962; Smith, Kaufman and Rutenburg, 1965; Monis, Wasserkrug and Seligman, 1965). It therefore appeared likely that the substrates alanyl‐ and methionyl‐4‐methoxy‐2‐naphthylamides would yield further improvement of localization of enzymatic sites and would be potentially useful for the demonstration of naphthylamidase in tissues such as white cells which are known to have a low content of this enzyme.In this report we present the data on the use of both substrates for the demonstration of naphthylamidase in human leucocytes.
The Effect of Acute Haemorrhage and Acute Haemolysis on the Intestinal Iron Absorption in the Rat
Authors: Chirasiri L. , Izak G. 
Published: March 2008

As thetotal body pool of iron is extremely small, a very sensitive and accurate mechanism is required to preserve the balance between the amount of iron entering the body and that being excreted. Although much effort has been concentrated on clarifying the nature of this regulating mechanism, the conclusions arrived at by different investigators vary widely. It has been stated that the body iron pool is maintained by controlled absorption, while excretion plays only a minor role (Moore, 1955; Pirzio–Biroli, Bothwell and Finch, 1958; Pirzio–Biroli and Finch, 1960). It has been proposed by some investigators that the iron content, or the degree of saturation of iron–binding protein in the intestinal epithelium are responsible for the amount of iron absorbed from the gut (Hahn, Bale, Ross, Balfour and Whipple, 1943; Granick, 1946; Stewart, Yuile, Claiborne, Snowman and Whipple, 1950). Others have denied the importance of these mechanisms (Brown, Dubach and Moore, 1958) and have advocated, instead, the importance of erythropoietic activity in the regulation of iron absorption (Chapelle, Gabrio, Stevens and Finch, 1955; Bothwell, Pirzio–Biroli and Finch, 1958; Reynafarje, Lozano and Valdivieso, 1959). Still other workers have demonstrated that iron is lost from the body in desquamated intestinal epithelium in a selective manner so that needed iron is conserved and excess eliminated (Conrad and Crosby, 1963; Crosby, 1963).In view of the many conflicting reports, it seemed of interest to explore the effect of anaemia due to blood loss and due to increased red‐cell destruction on the absorption of iron from isolated intestinal segments of the starving rat. The present communication deals with the results of these investigations.
Gastric Acidity and Iron Absorption
Authors: Jacobs A. , Rhodes J. , Peters D. K. , Campbell H. , Eakins J. D. 
Published: March 2008

achlorhydria has been recognized as an associated feature of iron deficiency anaemia for many years (Faber, 1909; Witts, 1930). There has, however, been little agreement as to the part played by gastric acid in the absorption of iron from the intestinal tract. Early workers produced evidence that iron absorption was greater in the presence of normal gastric acidity than in cases of achlorhydria (Minot and Heath, 1932; Heilmeyer and Plotner, 1936; Barer and Fowler, 1937). Others found that this was not the case (Moore, Arrowsmith, Welch and Minnich, 1939; Grace, Doig and Wolff, 1954; Pirzio‐Biroli, Bothwell and Finch, 1958). More recently Goldberg, Lochhead and Dagg (1963) and Cook, Brown and Valberg (1964) have shown that in some circumstances iron is better absorbed by subjects with normal gastric acid than in those with a histamine fast achlorhydria.In the present investigation quantitative studies of both iron absorption and of gastric acid production have been made in patients with iron deficiency anaemia and additional observations have been made in normal subjects. The relationship between iron absorption and gastric secretory capacity is examined.
Familial Thrombocytopenic Thrombocytopathy
Authors: Cullum Carol , Cooney D. P. , Schrier S. L. 
Published: March 2008

SUMMARYA unique family with thrombocytopenic thrombocytopathy is described and the relevant literature is reviewed. Two of the more severely affected members who have clinical bleeding and thrombocytopenia were studied in detail. Their platelets are large, fail to adhere to wound surfaces, and are rapidly removed from the circulation. Their platelet thromboplastic activity is sharply reduced relative to their increased content of phospholipid and total lipid. It is postulated that the genetic defect is transmitted as an autosomal dominant.
Erythropoietic Cell Proliferation during Recovery from Acute Haemorrhage
Authors: Lord B. I. 
Published: March 2008

SUMMARYRecovery of rats subjected to an acute haemorrhage by cardiac puncture has been followed during the subsequent 7 days. Cell proliferation in the spleen and bone marrow during this recovery process was studied by the autoradiographic technique.By 7 days, the circulating red cell volume was normal as judged by daily measurement of the haematocrit. Both the spleen and the bone marrow made approximately equal contributions to the recovery process. In addition, the liver made a very small contribution. It is suggested that the process of recovery is by stimulation of the stem cell compartment to produce more cells going through the erythroid maturation sequence. The maximum number of erythroid cells in the spleen occurs between 2 and 4 days and at this time the cells are dividing with a mean cycle time of about 15 hours. In returning to normal, this mean cycle time then gradually increases making less divisions during the maturation sequence possible and, therefore, producing mature cells at an increasingly slower rate. The marrow probably behaves in a similar manner but because it is a considerably larger and more diffuse organ than the spleen, the experimentally observed changes are not so dramatic and, therefore, less easily analysed.
Platelets in the Carcinoid Syndrome: A Chemical and Ultrastructural Investigation
Authors: Crawford N. , Sutton Maureen , Horsfield G. I. 
Published: March 2008

SUMMARYA combined chemical and electron microscopic study of normal platelets and platelets from patients with the carcinoid syndrome has revealed an association between their serotonin content and certain alterations in their cytoplasmic structure. In addition to a fibrillary structure of possible cytoskeletal significance, platelets also contain a system of microtubules and vesicles. When the platelet serotonin content is high this tubular structure is prominent and communicates with large vacuoles which may contain granular material. Normal platelets incubated with serotonin show similar alterations in structure. In addition, serial investigations of platelets from two carcinoid patients suggest that in addition to the normal active transport process for absorbing serotonin a diffusion process can operate when the cell is exposed to high environmental concentrations. The significance of these storage mechanisms in relation to normal and elevated platelet serotonin concentration is discussed.
Glandular Fever and Specific Viral Infections: Uptake of Tritiated Thymidine by Circulating Leucocytes
Authors: Besser G. M. , Davis Jane , Duncan Catherine , Kirk Barbara , Kuper S. W. A. 
Published: March 2008

SUMMARYThe circulating leucocyte nuclei in 20 out of 22 patients with glandular fever showed a raised level of uptake of tritiated thymidine in vitro. The uptake was confined to the glandular fever cells but in sonic cases it did not appear until the middle and late stages of the disease. In the few patients studied with the specific viral infection‐mumps, measles and rubella‐there was also increased thymidine labelling, but this was not seen in the two cases of chicken pox. This phenomenon in infections was similar to that seen in the reticuloses but was transient.
An Electron Microscope Study of Bone Marrow in Rheumatoid Disease
Authors: Wardle E. N. , Attan Jacqueline 
Published: March 2008

SUMMARYThe marrow of patients with various haematological complications of rheumatoid disease has been studied with the electron microscope. Although there is evidence that reticulum cells may be reluctant to turn over body iron, yet there is no evidence of iron excess in the reticulum cells of the marrow nor of a morphological defect of normoblast maturation.Iron transfer is normal. Whereas in the early stages of red cell development iron can be seen to enter the normoblasts from the reticulum cells by the distinct process of ropheocytosis, in the late normoblast and reticulocyte aggregates of unused iron pass back to the reticulum cells. The reticulum cell is therefore important in regulating the distribution of iron within the marrow.The reticulo‐endothelial system in rheumatoid disease shows evidence of response to antigenic stimulation. In particular a case of Felty's syndrome showed reticulum cell hyperplasia, lymphoblasts and material resembling rheumatoid factor in the granulocytes. Hyperplasia of the marrow reticulum may lead to a maturation arrest constituting ‘hypersplenism’.
Haemoglobin J‐Bangkok: A Clinical, Haematological and Genetical Study
Authors: Pootrakul S. , Wasi P. , Na‐Nakorn S. 
Published: March 2008

SUMMARYA Thai family with haemoglobins A + J‐Bangkok in nine persons is described. This rare abnormal pigment had identical electrophoretic mobility to other haemoglobins J, but, as α2β256Asp, is not similar to any previously described haemoglobin. Carriers of this haemoglobin were clinically and haematologically normal except for the presence of 47.4–67.2 per cent Hb J. It was also possible to follow the increment of Hb J‐Bangkok from 16.15 per cent in the cord blood to 46 per cent at 2½ months and to 55.18 per cent at 1 year of age. One person is believed to harbour both an α‐thalassaemia and Hb J‐Bangkok genes without evidence of interaction.
The Fine Structure of Fibrin
Authors: Kay D. , Cuddigan B. J. 
Published: March 2008

SUMMARYUsing negatively staining techniques fibrin clots have been examined by electron microscopy, and finer detail of the clot structure has been observed than previously reported. From these observations a model of fibrinogen is proposed having different dimensions from those which are generally accepted and it is suggested that the fibrin clot is formed by end‐to‐end polymerization of the monomer with a one third molecular length overlap between laterally adjacent fibrils.
A Diffraction Method for Measuring the Average Volumes and Shapes of Red Blood Cells
Authors: Child J. A. , King J. , Newman T. H. , Waterfield R. L. 
Published: March 2008

SUMMARYAn instrument and technique are described for determining MCV, MCD and D/T from the visual measurement of the diffraction rings produced by red cells; MCV from the unfixed spherical cells and MCD from the fixed discoidal cells.The method eliminates a serious error due to asymmetry in retinal sensitivity near the fovea.The accuracy of the measurements is assessed from the repeatability of the observations of individual observers, and from the agreement between those of different observers.The validity of the optical theory in the deduction of the cell dimensions from the diffraction measurements is confirmed in the case of spherical cells: (1) By the agreement found between the values of MCV obtained with the spherocytometer on the one hand, and with the electronic counter and centrifuge on the other. (2) By showing that the constants for the various diffraction rings produced by spherical cells have their theoretical values. However, the constants found for the rings produced by the fixed discoidal cells differ significantly from their theoretical values. Because of this, and because of the shrinkage of the fixed cells, the values for MCD and D/T are only relative. The same criticism applies to the standard method for determining these data from dried blood films; but in dried films the shrinkage is variable, whereas in the new method described the shrinkage is constant. Error arising from the intensity of light in a diffraction ring being proportional to the fourth power of the diameter of the cell was examined and found to be negligible in the case of D/T, and to reach a significant amount in MCV only when anisocytosis is extreme.The possibility is considered that in abnormal cells variable shrinkage due to fixation may produce spurious variations in D/T. However, low values for D/T are found in spherocytosis, and high values in thalassaemia, in which the cells are flattened. Further, measurements of unfixed discoidal cells suspended in their own serum gave values of D/T closely parallel to those derived from the fixed discoidal cells.Results may be misleading when a microcytic or macrocytic anaemia is responding to treatment, or following transfusion. The error can be recognized and, by centrifugation, the cells present before treatment can be separated from the newly formed cells and measured in the ordinary way.
The Effect of Collagen on Platelet Glycolysis and Nucleotide Metabolism
Authors: Loder P. Bronwen , Hirsh J. , de Gruchy G. C. 
Published: March 2008

Summary. Glycolytic activity and nucleotide metabolism were studied in normal resting platelets and platelets exposed to collagen. Lactate production was found to be a more sensitive index of glycolytic activity than glucose consumption. In the presence of added glucose, the rate of lactate production was linear for at least 60 minutes. In the absence of glucose, lactate production continued for 60 minutes and appeared to be independent of glucose for the first 10–15 minutes.Addition of both collagen and pure tropocollagen to the platelet suspension produced a significant and constant increase in glycolytic rate. This was associated with release of ATP and ADP and a small but significant increase in total ATP. Addition of ADP in concentrations similar to those released by collagen had no effect on glycolytic activity. Addition of calcium ions produced release of nucleotides but no increase in glycolytic rate. EDTA inhibited glycolysis both in the resting platelets and in the presence of collagen.It is suggested that the stimulation of glycolysis by collagen may be due to the action of collagen on one or more rate‐limiting glycolytic enzymes.
Deranged DNA Synthesis by Bone Marrow from Vitamin B12‐Deficient Humans*
Authors: Metz Jack , Kelly Alan , Swett Virginia Chapin , Waxman Samuel , Herbert Victor 
Published: March 2008

Summary. The synthesis of thymine DNA from deoxyuridine and uridine was studied by culturing human bone marrow for 1–3 hours in the presence of radioactive‐labelled nucleosides. In the current study, this in vitro system appeared useful to test the potential efficacy of agents (such as methionine) which might be used to improve or retard improvement of patients with megaloblastic anaemia.In the bone marrow from patients with B12‐deficient or folate‐deficient megaloblastic anaemia, there was defective incorporation of deoxyuridine into thymine DNA. This defect was partially corrected by added B12 in the B12‐deficient but not the folate‐deficient marrows, and completely corrected by folic acid (pteroylglutainic acid) in both types of deficient marrow. The folate antagonist rnethotrexate blocked the corrective effect of B12. Incorporation of labelled uridine into DNA of B12‐deficient megaloblastic marrow was enhanced less by B12 than by PGA. Vitamin B12 antagonists failed to depress the incorporation of labelled uridine into DNA in bone marrows from both normal and B12‐deficient patients.These results support the concept that inadequate DNA synthesis in B12 deficiency is due in large measure to blockade in folate metabolism brought about by lack of B12. 5‐Methyl‐tetrahydrofolate, which may accumulate in B12 deficiency, failed to correct the defect in DNA synthesis, adding further evidence to the concept of metabolic trapping of this form of folate in B12 deficiency. Thus, riboside reduction in man may be independent of B12, as it is in E. coli, rather than dependent on B12, as it is in L. leichmannii.
Changes in Erythrocyte Membrane and Autohaemolysis during in Vitro Incubation
Authors: Langley G. R. , Axell M. 
Published: March 2008

Summary. Spontaneous autohaemolysis occurs as sterile defibrinated blood is incubated at 37°C. This study was undertaken to identify the membrane changes which occurred during autohaemolysis and the effect upon these of supplementary glucose.After 24 hours of incubation the earliest membrane change recognized was the loss of small amounts of cholesterol; this occurred equally in incubations with and without added glucose. Spherocytes were prominent in incubations without added glucose but were infrequent when supplementary glucose was provided. During the second 24 hours of incubation cholesterol loss increased and phospholipids eluted from the cell surface. In this period of incubation cholesterol and phospholipid loss was less in incubations provided with supplementary glucose. The major individual phosphatides lecithin, sphingomyelin, phosphatidylethanolamine and phosphatidylserine were lost in proportion to their original concentration in the membrane. Membrane protein did not decrease as cell lipid loss occurred.
Fibrinogen Catabolism in Microangiopathic Haemolytic Anaemia
Authors: Baker L. R. I. , Rubenberg M. L. , Dacie J. V. , Brain M. C. 
Published: March 2008

Summary. Fibrinogen catabolism has been studied in six patients with microangiopathic haemolytic anaemia, three patients with fragmentary haemolytic anaemia following the insertion of valve prostheses into the heart and ten control patients. Increased rates of catabolism of 131 I‐fibrinogen were found in the patients with microangiopathic haemolytic anaemia. Evidence of enhanced fibrinolysis was not present.This finding suggests that intravascular coagulation is a feature of some cases of microangiopathic haemolytic anaemia and supports the hypothesis that the interaction of red cells with fibrin may result in the characteristic morphological appearances in these cases.