The Reactivation of the Red Cell Nucleus

1967 ◽  
Vol 2 (1) ◽  
pp. 23-28 ◽  
Author(s):  
H. HARRIS
Keyword(s):  
Hela Cell ◽  
Cell Nucleus ◽  
Rna Synthesis ◽  
Direct Relationship ◽  
Nuclear Volume ◽  
Red Cell ◽  
Primary Event ◽  
Rna And Dna ◽  
Nuclear Enlargement ◽  
Made In

When the nucleus of a mature hen erythrocyte is introduced into the cytoplasm of a HeLa cell it resumes the synthesis of RNA and DNA. This reactivation of the red cell nucleus in the heterokaryon is associated with a marked increase in its volume. There is a direct relationship between the volume of the nucleus and the amount of RNA which it makes. The nuclear enlargement is not a consequence of increased RNA synthesis, or of DNA synthesis: enlargement is the primary event, and the increase in RNA synthesis is determined by it. The possibility is considered that changes in nuclear volume may regulate not only the amount of RNA made in the nucleus but also the areas of chromatin on which it is made.

Changes in The Cytochemical Properties Of Erythrocyte Nuclei Reactivated By Cell Fusion

1969 ◽  
Vol 4 (1) ◽  
pp. 71-87 ◽  
Author(s):  
L. BOLUND ◽  
N. R. RINGERTZ ◽  
H. HARRIS
Keyword(s):  
Hela Cell ◽  
Cell Fusion ◽  
Dry Mass ◽  
Nuclear Chromatin ◽  
Red Cell ◽  
Melting Profile ◽  
Nuclear Composition ◽  
Erythrocyte Nucleus ◽  
Rna And Dna ◽  
Deoxyribonucleoprotein Complex

When the nucleus of a chick erythrocyte is introduced into the cytoplasm of a HeLa cell it resumes the synthesis of RNA and DNA. This reactivation of the red cell nucleus is associated with an increase in volume and with changes in nuclear composition. These changes have now been studied by quantitative cytochemical techniques. During the process of reactivation the dry mass of the erythrocyte nucleus shows a marked increase which takes place largely before the replication of the DNA begins. Within 24 h of cell fusion, some erythrocyte nuclei already contain an increased amount of DNA, and 48 h after fusion many of them contain twice the normal diploid amount, thus indicating that they have replicated their DNA completely. The physical properties of the nuclear deoxyribonucleoprotein complex also change. The ability of the nuclear chromatin to bind acridine orange increases 4- to 5-fold well before the synthesis of DNA begins; and changes in the melting profile of the deoxyribonucleoprotein suggest that its structure is loosened. This view is also supported by the observation that the reactivity of the erythrocyte nuclei to the Feulgen stain is altered during the early stages of reactivation.

Ribosomal RNA Synthesis and Processing in a Particulate Site in the HeLa Cell Nucleus

Science ◽  
1966 ◽  
Vol 154 (3750) ◽  
pp. 786-789 ◽  
Author(s):  
S. Penman ◽  
I. Smith ◽  
E. Holtzman
Keyword(s):  
Hela Cell ◽  
Ribosomal Rna ◽  
Cell Nucleus ◽  
Rna Synthesis ◽  
Synthesis And Processing

▾ Epoetin – an important advance

1992 ◽  
Vol 30 (8) ◽  
pp. 29.2-32
Keyword(s):  
Renal Failure ◽  
Recombinant Human Erythropoietin ◽  
Antibody Formation ◽  
Blood Transfusions ◽  
Red Cell ◽  
Important Advance ◽  
Human Erythropoietin ◽  
Cell Antibody ◽  
Erythropoietin Deficiency ◽  
Made In

Erythropoietin is the endogenous hormone controlling red blood cell production. Most is made in the kidneys; if they fail, erythropoietin levels fall and anaemia develops. Treatment of erythropoietin deficiency anaemia in patients with renal failure has depended on repeated blood transfusions. Despite transfusions most patients remain anaemic and in addition are exposed to the risks of transfusion, such as viral infection, iron overload and problems associated with red cell antibody formation. The erythropoietin gene has been cloned and recombinant human erythropoietin (rHuEPO) is now marketed under the generic name epoetin. In this article we discuss the use of epoetin to treat anaemia in patients with renal failure and other potentially responsive conditions.

Distinct RNA Synthesis Systems of the HeLa Cell

1970 ◽  
Vol 35 (0) ◽  
pp. 561-575 ◽  
Author(s):  
S. Penman ◽  
H. Fan ◽  
S. Perlman ◽  
M. Rosbash ◽  
R. Weinberg ◽  
...  
Keyword(s):  
Hela Cell ◽  
Rna Synthesis

scholarly journals Malaria and red cell genetic defects

Blood ◽  
1989 ◽  
Vol 74 (4) ◽  
pp. 1213-1221 ◽  
Author(s):  
RL Nagel ◽  
EF Jr Roth
Keyword(s):  
Culture System ◽  
Potential Role ◽  
Dna Analysis ◽  
Red Cell ◽  
Metabolic Products ◽  
Recombinant Technology ◽  
Host Parasite ◽  
Made In

Abstract The study of inherited RBC resistance to malaria has increased our knowledge of the biochemistry and physiology of the host-parasite interaction and suggested potential sites for therapeutic intervention. Discovery by Jensen and Trager of the in vitro culture system for P falciparum has facilitated research in this area. Known RBC defects may affect invasion, growth, or merozoite liberation (Fig 1). Significant advances made in understanding mechanisms underlying protection against malaria should not obscure the fact that the data are far from complete. More knowledge is needed about the influence of the erythrocyte cytoskeleton on invasion and growth of parasites as well as the potential role of phospholipids, erythrocyte enzymes other than G6PD, or other metabolic products. Application of DNA analysis and recombinant technology may have an increasing impact on study of the interaction of RBC defects with malarial parasites.

scholarly journals IRON METABOLISM

Blood ◽  
1949 ◽  
Vol 4 (8) ◽  
pp. 905-927 ◽  
Author(s):  
CLEMENT A. FINCH ◽  
JOHN G. GIBSON ◽  
WENDELL C. PEACOCK ◽  
REX G. FLUHARTY
Keyword(s):  
Iron Metabolism ◽  
The Other ◽  
Normal Rate ◽  
Red Cell ◽  
Clinical Factors ◽  
Hematologic Disorders ◽  
Iron Stores ◽  
Cell Destruction ◽  
Hemoglobin Production ◽  
Made In

Abstract By determining the percentage utilization of intravenously administered radioiron for hemoglobin production over a period of two to three weeks, certain measurements of internal iron metabolism can be made. With a normal rate of blood production, changes in per cent utilization reflect alteration in iron stores. Iron depletion is characterized by more rapid and more complete utilization of radioiron. States of iron excess in hemochromatosis can be identified by their profound depression of radioiron utilization. If, on the other hand, storage iron is not greatly altered, the percentage utilization is determined by the function of the erythropoietic tissue. In myelophthisic anemias, in uremia, and in infection, a similar depression of the curve is found. The rate of erythropoiesis may further be estimated by the slope of the utilization curve, and evidence of abnormal red cell destruction is found in early and abrupt plateau of the utilization curve. A correlation has been made in a variety of hematologic disorders between the radioiron utilization for hemoglobin production and the clinical factors which might be expected to affect iron metabolism in these patients.

NUCLEIC ACID SYNTHESIS AND TRANSFER IN NORMAL, SECOND GENERATION CHICK EMBRYO FIBROBLASTS

1961 ◽  
Vol 39 (10) ◽  
pp. 1625-1633 ◽  
Author(s):  
R. Bather ◽  
Elizabeth Purdie-Pepper
Keyword(s):  
Chick Embryo ◽  
Rna Synthesis ◽  
Second Generation ◽  
Acid Synthesis ◽  
Quantitative Estimates ◽  
Cytoplasmic Rna ◽  
Embryo Fibroblasts ◽  
Slight Rise ◽  
Zero Time ◽  
Rna And Dna

The stripping film technique of autoradiography has been used to study some aspects of RNA and DNA metabolism in chick embryo fibroblasts in second generation tissue culture.Approximately one third of the cells incorporated thymidine-H3into DNA in a 20-minute uptake period. The duration of DNA synthesis, the generation time (time elapsing between two successive cell divisions), and the duration of mitosis have been calculated and are very similar to the values obtained for pure strains of hamster cells maintained in culture for several months by another author.RNA synthesis, as measured by uridine-H3incorporation, occurred only in the nucleus and nucleolus. Both sites synthesized RNA simultaneously beginning at zero time. The ratio of the number of grains over the nucleolus to that over the whole nucleus remained constant throughout the uptake of uridine-H3and its transfer to the cytoplasm.A small amount of labelled soluble RNA precursors remain in the nucleus after removal of uridine-H3from the medium. This results in a slight rise in radioactivity of the nucleus after uridine-H3removal. RNA then leaves the nucleus rapidly and appears in the cytoplasm. The half life of RNA in the nucleus is about 4 hours. Some turnover of cytoplasmic RNA seems to occur after 8 hours but quantitative estimates of its rate cannot be made due to changing geometry of the cells as the RNA migrates from the nuclear to the peripheral parts of the cell.Finally, little or no RNA synthesis occurs for a period of about 30 minutes during contraction of the chromosomes in mitosis.

scholarly journals THE ELECTROPHORETIC MOBILITY OF RABBIT ERYTHROCYTES AND GHOSTS

1939 ◽  
Vol 22 (4) ◽  
pp. 545-553 ◽  
Author(s):  
Harold A. Abramson ◽  
Robert F. Furchgott ◽  
Eric Ponder
Keyword(s):  
Cell Membrane ◽  
Electrophoretic Mobility ◽  
Red Cells ◽  
Red Cell ◽  
Electrical Mobility ◽  
Freezing And Thawing ◽  
Made In

Measurements of the electrical mobility of washed rabbit red cells and of ghosts produced by hypotonic solutions, freezing-and-thawing, chloroform, and saponin were made in the Abramson horizontal microelectrophoresis cell. These different forms of lysis, which corresponds to a variety of degrees of injury to the red cell, are unaccompanied by any change in electrical mobility. These observations are discussed from the standpoint of the possible structure of the cell membrane and the action of lysins upon it.

The Finite Element Analysis of New Forged Coupler Knuckle

2013 ◽  
Vol 367 ◽  
pp. 122-125
Author(s):  
Guang Xin Wang ◽  
Xiang Shun Bu ◽  
Lin Jie Li ◽  
Li Li Zhu
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Direct Relationship ◽  
Element Analysis ◽  
Compression Load ◽  
The Finite Element Analysis ◽  
Simulation Results ◽  
Element Technique ◽  
Working Situation ◽  
Made In

As one of the most important load-bearing parts, coupler knuckle has a direct relationship with the safety in operation and reliability of the freight trains. A new forged coupler knuckle is made in order to meet the challenge to export ore train to Australia. Using the finite element technique, the stress characteristics of forged coupler knuckle under 1225kN load in tension and 1500kN compression load are evaluated. Simplify the load and boundary condition depend on the real working situation, the numerical simulation results coincide with experimental data.

Relationship between chromatin structure and replication in mouse L-cells

1980 ◽  
Vol 58 (12) ◽  
pp. 1359-1369 ◽  
Author(s):  
Rose Sheinin ◽  
G. Setterfield ◽  
I. Dardick ◽  
G. Kiss ◽  
M. Dubsky
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
De Novo ◽  
Nuclear Volume ◽  
Chromatin Protein ◽  
Structural Reorganization ◽  
L Cells ◽  
Inhibition Of Dna Synthesis ◽  
De Novo Protein Synthesis ◽  
Nuclear Enlargement

Mouse L-cells treated with cytosine arabinoside, hydroxyurea, fluorodeoxyuridine, methotrexate, or mitomycin C rapidly cease DNA synthesis and stop dividing. Such inhibition of DNA replication is followed by interruption of formation of lysine- and arginine-containing proteins, including chromatin-bound histones, and by a major reorganization of the heterochromatin of the central nucleoplasm, manifest as disaggregation of large clumps of this condensed chromatin. Morphometric analysis revealed both cell and nuclear enlargement in cells treated with such antimetabolites of DNA replication. These observations are in contrast to those made with WT-4 cells starved of isoleucine or treated with cycloheximide. Isoleucine depletion was associated with inhibition of DNA synthesis and continued increase of cell and nuclear volume, but not with massive disaggregation of heterochromatin. Cycloheximide produced inhibition of DNA synthesis and protoplasmic growth, and also prevented structural reorganization of chromatin. A model is presented which suggests that initiation of chromatin replication is associated with a process, dependent upon de novo protein synthesis, which results in chromatin disaggregation. This can be revealed by inhibition of the correct replication of chromatin DNA and chromatin protein.

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