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Abstract
To evaluate the effectiveness of the trauma care system in the Hudson Valley Emergency Medical Services (EMS) Region, (with no designated regional trauma care center) 421 consecutive trauma autopsy reports for 1979-80 were analyzed. Of the 421 trauma patients, 194 died at the scene (DAS), most from vehicular accidents. The remaining 227 patients were triaged into the EMS system. Ninety-five were dead on arrival (DOA) at medical facilities; of 132 (31 per cent) who arrived alive at hospitals, 35 died in emergency rooms and 97 died later as inpatients. Nearly 60 per cent of the deaths involved brain injuries. A panel of five physician-evaluators examined the pathologist's analysis of those deaths considered to have been possibly preventable and concluded that 10 deaths (7.6 per cent) of in-hospital cases were preventable. The study showed the need for primary prevention of accidents to decrease the number of victims (46 per cent) who died at the scene and those (23 per cent) who were dead on arrival at hospitals.
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77
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Seal SN, Schmidt A, Marcus A. Eukaryotic initiation factor 4A is the component that interacts with ATP in protein chain initiation. Proc Natl Acad Sci U S A 1983; 80:6562-5. [PMID: 6579543 PMCID: PMC390393 DOI: 10.1073/pnas.80.21.6562] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Protein synthesis in a resolved homogenate of wheat germ requires ATP and eight factors functioning at the level of protein chain initiation. To identify the component(s) interacting with ATP, the different factors were treated with the ATP affinity analogue 5'-p-fluorosulfonylbenzoyladenosine (FSBA) and tested for their function in protein synthesis. The activity of eukaryotic initiation factor 4A (eIF4A) was strongly curtailed, whereas all other factors were unaffected. At a concentration of 250 microM, AMP, ADP, and ATP protected eIF4A against FSBA inactivation, whereas at a concentration 50 microM, protection was afforded only by ATP. GTP did not protect at a concentration of 250 microM. In another approach, the substrate analogue 2',3'-O-(2,4,6-trinitrophenyl)adenosine 5'-triphosphate (TNP-ATP) was found to inhibit protein synthesis in a manner, at least in part, competitive with ATP. Supplementing a TNP-ATP inhibited reaction with eIF4A substantially reversed the inhibition. Except for a small effect by factor C1, no reversal was obtained with any other component. Finally, a preincubation of ribosomes with ATP, mRNA, and eIF4A resulted in the formation of a complex capable of TNP-ATP-resistant amino acid incorporation. These data are interpreted to indicate that the primary interaction of ATP is with eIF4A. A model is proposed reconciling this conclusion with other observations relevant to the mRNA . ribosome attachment reaction.
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78
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Seal SN, Schmidt A, Marcus A. Wheat germ eIF2 and CoeIF2. Resolution and functional characterization in in vitro protein synthesis. J Biol Chem 1983; 258:10573-6. [PMID: 6885794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
A factor that binds Met-tRNAiMet in a ternary complex (eucaryotic initiation factor (eIF2) ) and an auxiliary component that strongly stimulates the activity of the binding factor (CoeIF2) have been purified from extracts of wheat germ. The molecular weights of the two factors, as determined by glycerol gradient centrifugation and sodium dodecyl sulfate gel electrophoresis, are 88,000 and 20,000, respectively. Incubation of wheat germ eIF2 with gamma-[32P]ATP and alpha-subunit kinase results in the phosphorylation of a Mr = 40,500 subunit, while no specific phosphorylations are found when the eIF2 is incubated with the beta-kinase. These data are interpreted to suggest that CoeIF2 is a monomer of Mr = 20,000 while eIF2 may be a dimer, containing subunits of Mr = 40,000 and 50,000. Both eIF2 and CoeIF2 are strongly required for in vitro amino acid polymerization, providing the first direct demonstration of the function of CoeIF2 in protein synthesis.
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79
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Marcus A. Book Review: Advances in Nutritional Research. Ann Clin Biochem 1983. [DOI: 10.1177/000456328302000519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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80
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Datta K, Marsh L, Marcus A. Early growth of wheat embryonic axes and the synthesis of RNA and DNA. PLANT PHYSIOLOGY 1983; 72:394-7. [PMID: 16663013 PMCID: PMC1066244 DOI: 10.1104/pp.72.2.394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The requirement for the synthesis of RNA and DNA in early germination of wheat (Triticum aestivum var Newana) embryonic axes has been studied by incubating embryos in the presence of appropriate inhibitors and monitoring both embryo growth and the rates of specific metabolic processes. Experiments with 5-fluorouridine showed that both rRNA and DNA synthesis could be curtailed by 60 to 70% without affecting embryo growth to 24 hours. Similarly, the presence of mitomycin C and methotrexate inhibited DNA synthesis 70%, with only a small effect on growth. Experiments with a range of concentrations of cordycepin and alpha-amanitin indicated that mRNA synthesis could be curtailed by 30 to 40% within the first 8 hours of germination with only a small effect on embryo growth. Thus, at least the initial phases of seed embryo germination are not closely linked to the synthesis of mRNA, rRNA, or DNA. Maximal sensitivity of embryo growth was obtained with cycloheximide and 2-(4-methyl-2,6-dinitroanilino)-N-methyl propionamide, supporting the idea that protein synthesis is the macromolecular process most closely linked to early germination.
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81
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Zhu ZP, Marsh L, Marcus A. De novo synthesis of 3'-nucleotidase in germinating wheat embryo. PLANT PHYSIOLOGY 1983; 71:295-9. [PMID: 16662820 PMCID: PMC1066027 DOI: 10.1104/pp.71.2.295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The enzyme 3'-AMP nucleotidase was purified 2,500- to 5,000-fold from extracts of an acetone powder of wheat (Triticum aestivum) embryonic axes germinated for 40 hours. Sodium dodecyl sulfate acrylamide gel electrophoresis and chromatography on Biogel-P100 indicate that the enzyme is monomeric with a molecular weight of 39,000. Extracts of embryos germinated up to 6 hours have only 1% of the 40-hour level of enzyme activity. To see if the increase to 40 hours represents de novo synthesis, extracts were compared for their ability to react with a rabbit antibody prepared against the enzyme. In immunodiffusion tests, 40-hour extracts showed a strong precipitin line coincident with that of the purified enzyme, whereas no precipitation was observed with 1-hour extracts. When the enzyme present in 40-hour extracts was partially inactivated by EDTA, it still blocked the ability of the antibody to inhibit enzyme activity. Extracts of 1-hour embryos, in contrast, were not able to block the inhibitory activity of the antibody. Embryos allowed to take up (35)SO(4) between 40 and 46 hours of germination synthesized (35)S-labeled 3'-nucleotidase. In contrast, no radioactive protein synthesized by embryos during the first 6 hours of germination coincided on gel electrophoresis with the enzyme. These results indicate that the increase in 3'-nucleotidase activity is a consequence of de novo synthesis of the enzyme.
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82
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Seal SN, Schmidt A, Marcus A. Fractionation and partial characterization of the protein synthesis system of wheat germ. I. Resolution of two elongation factors and five initiation factors. J Biol Chem 1983; 258:859-65. [PMID: 6549754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
Wheat germ S100 supernatant was resolved into 10 components, all of which are required for tobacco mosaic virus RNA-directed incorporation of amino acid into protein. Two of the components, C2b and C2a, are, respectively, elongation factors 1 and 2, having molecular weights of 51,000 and 72,000. A third factor (C2e) binds Met-tRNA in a GTP-requiring reaction and is absolutely required for the formation of both 40 S ribosome.Met-tRNAiMet and 80 S ribosome.Met-tRNAiMet complexes. This factor is considered to be eucaryotic initiation factor 2. Formation of 80 S ribosome Met-tRNAiMet complexes is augmented 2 to 3-fold by the simultaneous addition of an mRNA, factor C1, and fraction D2(a + b). Factor C1 also reverses the inhibition of translation by an increased concentration of monovalent cations and promotes the translation of a "competitively inhibited" mRNA. These observations suggest that factor C1 and either factor D2a and D2b (or both) function in mRNA attachment reactions. Factor C1 has a molecular weight of 115,000 and appears to be made up of two or three subunits. Factor D2b has been purified to essential homogeneity and has a molecular weight of 55,000. Its interaction with mRNA and its molecular weight suggest that this factor is the wheat germ equivalent of reticulocyte eucaryotic initiation factor 4A.
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83
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Seal SN, Schmidt A, Marcus A. Fractionation and partial characterization of the protein synthesis system of wheat germ. II. Initiation factors D1 (eucaryotic initiation factor 3), D2c (eucaryotic initiation factor 5), and D2d (eucaryotic initiation factor 4C). J Biol Chem 1983; 258:866-71. [PMID: 6549755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
This report characterizes three components of the fractionated wheat germ protein synthesizing system, factors D1, D2c, and D2d. FActor D1 has a molecular weight of about 420,000 and is comprised of 7-10 components varying in molecular mass between 28,000 and 105,000 daltons. The factor is absolutely required for the formation of both 40-S ribosome.Met-tRNAiMet and 80 S ribosome.Met-tRNAiMet complexes except at low Mg2+ concentration, where significant 40 S ribosome complex formation can be obtained without D1, provided the reaction products are fixed with glutaraldehyde. Factor D1 can be shown to interact with the 40-S ribosome subunit in two ways: the change in sedimentation of the ribosome subunits that occurs when ribosomes are incubated with the factor under dissociating conditions and the prevention of the reformation of 80 S ribosomes by a prior incubation of ribosome subunits with the factor. Factor D2c has a molecular mass of about 100,000 daltons and is absolutely required for the conversion of 40 S ribosome.Met-tRNAiMet complexes to 80 S ribosome.Met-tRNAiMet. Factor D2d strongly augments the D2c-dependent formation of 80S ribosome.Met-tRNAiMet complexes, with the requirement for D2d most apparent when the complexes are fixed with glutaraldehyde, a treatment that labilizes the 80 S ribosome-bound Met-tRNAiMet. Addition of factor D2d to a 40 S ribosome.Met-tRNAiMet synthesizing system also increases the amount of complex obtained 2-5-fold. Consideration of these characteristics establishes components D1, D2c, and D2d as wheat germ eucaryotic initiation factors 3, 5, and 4C, respectively.
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84
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Marcus A, Short AH. Sensitive questions. MEDICAL TEACHER 1983; 5:44-45. [PMID: 24476366 DOI: 10.3109/01421598309147560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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85
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Seal SN, Schmidt A, Marcus A. Fractionation and partial characterization of the protein synthesis system of wheat germ. II. Initiation factors D1 (eucaryotic initiation factor 3), D2c (eucaryotic initiation factor 5), and D2d (eucaryotic initiation factor 4C). J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)33130-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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86
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Seal SN, Schmidt A, Marcus A. A heat-stable protein synthesis initiation factor from wheat germ. J Biol Chem 1982; 257:8634-7. [PMID: 6920387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
A protein synthesis initiation factor of molecular weight 21,500 has been purified to homogeneity from extracts of wheat germ. The factor, referred to as D2d, is stable to heating for 5 min at 75 degrees C and loses less than 15% of its activity upon a similar treatment at 90 degrees C. In contrast, all other wheat germ protein synthesis factors are inactivated by heating for 5 min at 65 degrees C. Formation of 80 S ribosome . Met-tRNAiMet complexes from 40 S ribosome . Met-tRNAiMet complexes, as measured by the binding of [3H]Met-tRNAiMet, is almost completely dependent upon the presence of component D2d. The shift in sedimentation of the ribosome subunits to the 80 S ribosome region, however, occurs in the absence of factor D2d. Thus, the role of the factor is not to join the ribosomal subunits, but rather to keep the Met-tRNAiMet bound to the ribosome. The formation of 40 S ribosome . Met-tRNAiMet complexes is increased 2-fold by the presence of factor D2d. Fixing this complex with glutaraldehyde results in the binding of more Met-tRNAIMet than a nonfixed incubation in the presence of D2d. These results suggest that the primary interaction with the ribosomal subunit can occur in the absence of factor D2d, but that the presence of the factor stabilizes the ribosome-bound Met-tRNAiMet.
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87
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Seal SN, Schmidt A, Marcus A. A heat-stable protein synthesis initiation factor from wheat germ. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34175-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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88
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Marsh L, Datta K, Marcus A. Germination of wheat embryos and the transport of amino acids into a protein synthesis precursor pool. PLANT PHYSIOLOGY 1982; 70:67-73. [PMID: 16662481 PMCID: PMC1067087 DOI: 10.1104/pp.70.1.67] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Wheat (Triticum aestivum L. var. Lew) embryonic axes take up externally supplied radioactive amino acid (from a solution greater than 2 millimolar) such that the specific radioactivity of the total internal amino acid rapidly reaches that of the external solution. Nevertheless, incorporation of radioactive amino acid into protein increases steadily as the concentration of external amino acid is increased, indicating that the amino acid that is precursor to protein synthesis is not in equilibrium with the total internal amino acid pool. When the external source of amino acid is removed, incorporation of radiolabeled amino acid into protein continues at a rate comparable to that of embryos maintained in the radioactive solution. In explanation of these data, it is suggested that there are two separate cytoplasmic pools of amino acids, one a protein synthesis precursor pool, and the second, an expandable pool into which exogenous radioactive amino acids are taken up. The protein synthesis pool is fed at a limited rate from the expandable pool and at a far greater rate from an endogenous source. As a consequence, the specific activity of the amino acid that is the precursor for protein synthesis is considerably below that of the total internal pool and is determined by the rate of movement into the protein synthesis pool from the expanded radioactive cytoplasmic pool.The rate of movement of amino acids from the expandable pool into the protein synthesis pool increases approximately 5-fold during the initial 4.5 hours of embryo germination. When this change is considered in analyzing the relative rates of protein synthesis, there is probably no more than a 2-fold increase in protein synthetic capacity between embryos germinated for 1.5 and 4.5 hours. The leveling off of the change in transport capacity after 4.5 hours suggests that the earlier increase in the rate of this process may be a necessary step before the embryos can begin to accelerate their growth rate.
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89
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Rodaway S, Datta K, Marcus A. A novel effect of 6-azauridine on growth and protein synthesis in wheat embryonic axes. Arch Biochem Biophys 1982; 215:140-7. [PMID: 6178369 DOI: 10.1016/0003-9861(82)90288-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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90
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Hymes KB, Cheung T, Greene JB, Prose NS, Marcus A, Ballard H, William DC, Laubenstein LJ. Kaposi's sarcoma in homosexual men-a report of eight cases. Lancet 1981; 2:598-600. [PMID: 6116083 DOI: 10.1016/s0140-6736(81)92740-9] [Citation(s) in RCA: 423] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The clinical findings in eight young homosexual men in New York with Kaposi's sarcoma showed some unusual features. Unlike the form usually seen in North America and Europe, it affected younger men (4th decade rather than 7th decade); the skin lesions wee generalised rather than being predominantly in the lower limbs, and the disease was more aggressive (survival of less than 20 months rather 8-13 years). All eight had had a variety of sexually transmitted diseases. All those tested for cytomegalovirus antibodies and hepatitis B surface antigen of anti-hepatitis B antibody gave positive results. This unusual occurrence of Kaposi's sarcoma in a population much exposed to sexually transmissible diseases suggests that such exposure may play a role in its pathogenesis.
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91
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Marcus A, Weksler B, Jaffe E, Safier L, Ullman H, Broekman M, Dorso C, Brown S. Arachidonic acid metabolism in platelets and endothelial cells. Prog Lipid Res 1981; 20:431-4. [PMID: 6804972 DOI: 10.1016/0163-7827(81)90076-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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92
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Rodaway S, Marcus A. In vivo synthesis of 6-azauridine 5'-triphosphate and incorporation of 6-azauridine into RNA of germinating wheat embryonic axes. J Biol Chem 1980; 255:8402-4. [PMID: 6157685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The cytostatic effect of 6-azauridine on cell growth is generally regarded to be a consequence of the inhibition of de novo pyrimidine biosynthesis by the metabolite, 6-azauridine 5'-monophosphate. We show here that wheat embryonic axes further metabolize 6-azauridine to the 5'-triphosphate and incorporate the analogue into RNA, thus offering an alternative mechanism for growth inhibition. At a level of 6-azauridine required to maximally inhibit UTP biosynthesis, the ratio of 6-azaUTP to UTP is about 2:1 and substitution of 6-azauridine for uridine in new RNA is on the order of 1 in 18. The new metabolites of 6-azauridine are identified by high pressure and thin layer chromatography coupled with enzyme treatments.
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93
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Huang BF, Rodaway SJ, Wood A, Marcus A. RNA synthesis in germinating embryonic axes of soybean and wheat. PLANT PHYSIOLOGY 1980; 65:1155-9. [PMID: 16661351 PMCID: PMC440501 DOI: 10.1104/pp.65.6.1155] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The rate of synthesis of RNA during early germination of wheat and soybean embryos was investigated by ascertaining the incorporation of radioactive uridine into RNA. In wheat embryos, where the lag period preceding rapid growth is 5.5 hours, there is a 2-fold increase in RNA synthesis between 1.5 and 5.5 hours, with half of the increase occurring by 3.5 hours. In soybean axes, where the lag period is 9.5 hours, the increased rate of RNA synthesis is 5.5-fold between 1.5 and 9.5 hours, with three fourths of this increase occurring after 4 hours.Analysis of the ratio of radioactivity incorporated into the 18S and 26S rRNAs of the germinating embryos provided a further measure of the increased rates of RNA synthesis. With wheat embryos, the 26S/18S ratio increased from 1.0 at 1.5 hours to 1.5 at 3.5 hours, while with the soybean axes, distinct ribosomal patterns were obtained only after 4 hours and the 26S/18S rRNA ratio increased from 0.4 at 4 hours to 1.0 at 9 hours. The extent of methylation of the rRNA synthesized at 4 and 9 hours in the soybean axes was similar, indicating that the methylating capacity of the axes is probably not rate limiting to rRNA synthesis. In both seed embryo systems the level of UTP increased 2 to 3-fold during the lag phase of germination. With wheat embryos, the time course of the increase in UTP correlated approximately with the change in the rate of RNA synthesis. With the soybean axes, however, the increase in the rate of RNA synthesis occurred predominantly after the rise in the level of UTP.
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94
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Marcus A, Simpson MA, Patterson A, Kay S, Clarke R. WHO Has Got it Right: A New 16mm film M&B May&Baker Aspects of anaerobic infection. MEDICAL TEACHER 1980; 2:61-62. [PMID: 24479391 DOI: 10.3109/01421598009071270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hilaire Belloc wrote "They answered as they took their fees 'There is no cure for this disease.'" The profession to which he was referring is probably transparent, but what may be a little more opaque is that his comment could apply to those individuals who claim to run courses suitable for medical educators, including those who come from developing countries. However, for those who read the paper Progress of the WHO Global Teaching Training Programme 1969-1979 (WHO/EDUC/79.178), the truth of Belloc's words is as painful as Mark Twain's plea to "Always tell the truth because it will gratify the few and astonish the many."
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95
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Marcus A, Hope K, Simpson MA, Patterson A, Montgomery C, Clarke R. A 'soft option' no more. MEDICAL TEACHER 1980; 2:5-6. [PMID: 24480000 DOI: 10.3109/01421598009072164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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96
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Rodaway S, Marcus A. Germination of soybean embryonic axes: nucleotide sugar metabolism and initiation of growth. PLANT PHYSIOLOGY 1979; 64:975-81. [PMID: 16661117 PMCID: PMC543176 DOI: 10.1104/pp.64.6.975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
UDP-Sugars comprise the dominant class of nucleotide sugars in isolated soybean axes during early germination. While "dry" axes contain 1 nanomole per axis of UDP-sugars, further synthesis is initiated upon imbibition such that the concentration of total UDP-sugars reaches 8 nanomoles per axis or roughly 1 millimolar after 10 hours, when the axes begin to elongate. The GDP-sugars are essentially absent before imbibition, accumulate rapidly for 90 min to 173 picomoles per axis, then decrease somewhat, reattaining the earlier peak level shortly before growth begins. Meanwhile, the level of ADP-sugars is unchanged. These data indicate that the 10-hour lag period preceding axis growth does not result from a diminished ability to synthesize a major category of nucleotide sugars.Relative rates of synthesis of individual UDP- and GDP-sugars were determined by incorporation of [(3)H]uridine or [(3)H]guanosine. The distribution of label in the different classes of UDP-sugars and in the single class of GDP-sugar was quantitatively similar when analyzed before, at the onset, or during early growth. It therefore seems unlikely that synthesis of a key nucleotide sugar controls the initiation of growth.The possible relevance of nucleotide sugars to growth is discussed and new methods for enzymic analysis of picomole levels of nucleotide sugars are described.
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97
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Herson D, Schmidt A, Seal S, Marcus A, van Vloten-Doting L. Competitive mRNA translation in an in vitro system from wheat germ. J Biol Chem 1979; 254:8245-9. [PMID: 468823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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98
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Saccuzzo DP, Kerr M, Marcus A, Brown R. Input capability and speed of processing in mental retardation. JOURNAL OF ABNORMAL PSYCHOLOGY 1979; 88:341-5. [PMID: 479455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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99
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Ramagopal S, Marcus A. RNA synthesis in growing and stationary cells of a culture of Scarlet Rose. Disproportionate synthesis of ribosomal subunits in the stationary state. J Cell Physiol 1979; 98:603-11. [PMID: 438304 DOI: 10.1002/jcp.1040980318] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
RNA synthesis has been investigated in resting and growing cells of a culture of Scarlet rose. The rates of messenger RNA (mRNA) and ribosomal RNA (rRNA) synthesis are five- and ten-fold higher, respectively, in the growing culture. In stationary phase cultures, newly synthesized 26S and 18S rRNA do not appear in the cytoplasm in equimolar amounts. Rather, the 26S/18S ratio of [3H]-uridine labeled rRNA of stationary cells ranged from 0.9 to 1.3 while the ratio of the corresponding fraction from growing cells was 1.6 to 2.0. A similar result was obtained when cells were labeled with [3H-CH3] methionine. Pulse chase experiments demonstrated that the nascent pre-rRNA in resting cells could be chased into polysomes. These data are interpreted to indicate that a major part of the regulation of rRNA synthesis in stationary cells is at the level of the processing of the rRNA transcript.
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100
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Seal SN, Schmidt A, Tomaszewski M, Marcus A. Inhibition of noncapped mRNA translation by the cap analogue, 7-methylguanosine-5'-phosphate. Biochem Biophys Res Commun 1978; 82:553-9. [PMID: 208566 DOI: 10.1016/0006-291x(78)90910-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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