- Volume 4, Issue 1, 1969
Volume 4, Issue 1, 1969
- Articles
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Properties of the Rat Submaxillary Gland Virus Haemagglutinin and Antihaemagglutinin and Their Incidence in Apparently Healthy Gnotobiotic and Conventional Rats
More LessSUMMARYThe properties of the rat submaxillary gland (RSMG) virus haemagglutinin and its serum antihaemagglutinin, and their incidence and relative titres in gnotobiotic and conventional Sprague-Dawley rats of various ages were investigated. The haemagglutinin was stable at -55° for as long as years and retained its activity after 2 hr at 60°. Various carbohydrases and cobra venom had no effect upon its titre; however, 2 × crystallized trypsin and pronase reduced the titre substantially. The haemagglutinin was not recovered from the submaxillary glands of rats less than 8 weeks of age, though 3-, 5-, and 6-week-old animals had low serum antihaemagglutinin titres. A general correlation was observed between the haemagglutinin and antihaemagglutinin titres of the animals; higher serum antihaemagglutinin titres occurred in those rats with higher haemagglutination titres. No significant difference was usually seen between the haemagglutination titres of gnotobiotic and conventional rats of the same age. The antihaemagglutinin titres of some conventional rats, however, tended to be two- to fourfold greater than those of gnotobiotic animals of comparable age with identical haemagglutination titres. Sera which were heated at 56° for 30 min. absorbed with kaolin, incubated with trypsin, potassium or sodium periodate, or receptor-destroying enzyme showed no reduction in their antihaemagglutinin titres. Sucrose density-gradient centrifugation studies indicated that the antihaemagglutinin was associated with the 7 S fraction; however, some sera showed antihaemagglutinin activity in the 19 S fraction. The haemagglutinin of rat submaxillary gland virus was not inhibited by antisera prepared in mice against reovirus 3, Kilham’s rat virus, Toolan’s H-1 virus or Crawford’s minute virus of mice.
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The Multiplication Regions and Interaction of Acute and Chronic Bee-paralysis Viruses in Adult Honey Bees
L. Bailey and R. G. MilneSUMMARYSerological and infectivity tests showed that acute bee-paralysis virus accumulated in the heads of acutely paralysed bees, especially in the hypopharyngeal glands, and that much virus also occurred in the brain, where particles resembling acute bee-paralysis virus were made visible by electron microscopy. Similar tests showed that chronic bee-paralysis virus was concentrated in the brains of chronically paralysed bees. Electron microscopy of the brains showed particles resembling chronic bee-paralysis virus but these may have been synaptic vesicles or sectioned microtubules, since similar particles were also seen in the brains of apparently healthy bees. These particles also resembled particles that were seen in sections of pellets of purified chronic bee-paralysis virus, and that were electron-transparent in the centre.
Many bees injected with acute bee-paralysis virus and kept at 35° remained apparently healthy though they contained at least as much virus as bees injected with acute bee-paralysis virus and kept at 30°, all of which died of acute paralysis. Conversely, chronic bee-paralysis virus multiplied more at 30° than at 35°, though it killed bees more slowly at the lower temperature. When acute bee-paralysis virus and chronic bee-paralysis virus were injected together into single bees, acute bee-paralysis virus multiplication was depressed at 35° and chronic bee-paralysis virus multiplication was depressed at 30°.
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Induction of a Defective Phage and DNA Methylation in Escherichia coli 15t-
More LessSUMMARYGrowth of Escherichia coli 15t − in a thymine-containing medium with any of several antibacterial agents (5-aminouracil, mitomycin C, nalidixic acid or hydroxyurea) increased the 6-methyladenine content of the extractable DNA and the DNA methylase activity. Similar changes occurred after transient (45 min.) thymine deprivation but not with other antibacterial agents such as penicillin, phenylethyl alcohol, novobiocin. Associated with the increases in 6-methyladenine content and DNA methylase activity was the induction of a defective bacteriophage. Similar effects were noted in the wild-type E. coli 15.
Escherichia coli is a thymine auxotroph derived from E. coli 15t −. It was selected for its resistance to mitomycin C. Neither phage particles nor changes in DNA methylase or 6-methyladenine content were produced in 15t − R under conditions leading to such effects in 15t −.
It is postulated that the rapid killing of ‘thymineless death’ in Escherichia coli 15t − is secondary to induction of a defective bacteriophage. The increases in 6-methyladenine content and DNA methylase activities that occur with thymine deprivation or treatment with the above antibacterial agents are thought to represent phage-induced changes.
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Transformation of Rat Embryo Cells by Adenovirus Type 1
More LessSUMMARYPrimary rat embryo cells were transformed by adenovirus 1. The transformed cells formed foci of multilayered growth in monolayer cultures; cell lines were derived from such foci. A virus stock containing 1.1 × 109 virus particles and 1.5 × 108 p.f.u./ml. contained 2.3 × 102 focus-forming units/ml. when assayed in rat embryo cells. Approximately 4.8 × 106 total virus particles or 6.5 × 105 p.f.u. were required to induce one focus of transformed cells. The transformation rate was 0.0003% for cells exposed to about 2 p.f.u./cell. The transformed cells contained adenovirus 1 specific tumour antigens when tested by immunofluorescent and complement-fixation reactions. They also synthesized adenovirus 1 specific RNA which forms RNase-resistant hybrids with adenovirus 1 DNA.
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The DNA of a Minute Virus of Mice
More LessSUMMARYThe base composition of DNA from a minute virus of mice was determined by hydrolysis of 32P-labelled DNA to give 3′ and 5′ nucleotides. The analyses were consistent only with a single-stranded structure for the virus DNA. This was confirmed by the results of nearest neighbour base sequence analyses. Comparison of minute virus of mice with phage φX 174 and adeno-associated virus type 1 showed a close similarity of minute virus of mice and φX 174 and suggested that all three small DNA virus particles contain not more than 1.7 × 106 daltons of DNA.
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Antigenic Differences Between Wild Type and Mutants of Bacteriophage λ
More LessSUMMARYThe clear-plaque mutants, phage λgv (large plaque, virulent inducer mutant) and λgc (large clear plaque), both types isolated from the same wild-type phage λ, were neutralized by antiserum to phage λ+ at a much slower rate than λ+. For the anti-wild-type serum the neutralization constant (K) was 111 min.−1 for phage λ+, whereas for phage λgv it was only 27 min.−1. On the other hand, antiserum to phage λgv neutralized all three phages at similar rates (K = 84, 76 and 70 min.−1 for λgv, λgc and λ+ respectively). When anti-wild-type serum (K = 96 min.−1 for λ+) was tested against 50 independent λgv-type mutants, it gave a mean K value of 28 min.−1 with 42 of the isolates. Three of the isolates, with mean K value (93 min.−1) equivalent to that for λ+, produced plaques of unusual morphology in certain conditions. With the other five λgv isolates, the serum showed a mean K value of 53 min.−1. The same anti-wild-type serum neutralized phage λg (large turbid plaques) at approximately the same rate (K = 34 min.−1) as the majority of the λgv isolates, whereas for λmi (minute turbid plaque) the rate was greater (K = 123 min.−1) than for λ+ and was intermediate (K = 44 min.−1) for λm5co (medium cocarde plaque). These results indicate that the composition or structure of tail components can vary in different phage λ mutants, and this feature of the phage particle is not directly associated with loss of ability to lysogenize the host bacterium, Escherichia coli.
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Quantum Yields for Inactivation of Tobacco Mosaic Virus Nucleic Acid by Ultraviolet Radiation (254 nm.)
More LessSUMMARYThe quantum yield, under non-photoreactivating conditions, for inactivation of tobacco mosaic virus RNA by ultraviolet radiation (254 nm.) is independent of the RNA concentration but varies appreciably with the ionic strength of the irradiation solvent, being approximately three times greater in water than in 0.1 m-potassium phosphate buffer. Photoreactivation of inactivated tobacco mosaic virus RNA is dependent on RNA concentration, ionic strength of solutions during irradiation, and on the light quality used for photoreactivation. These data can be interpreted as evidence that pyrimidine hydrate is a lethal lesion at least in RNA irradiated at low ionic strength.
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Incorporation of Lipids into Herpes Simplex Virus Particles
More LessSUMMARYThe synthesis of lipids in BSC 1 cells and their association with herpes simplex virus was studied. Radioactive choline was found to be incorporated mainly into lecithin. Infection of cells with herpes simplex virus did not affect the synthesis of cellular lipoproteins. Infected cells, prelabelled with radioactive choline, yielded virus particles which contained radioactively labelled cellular lipids. Treatment of herpes virus particles with sodium deoxycholate caused the dissociation of the particles and the release of capsomeres and soluble proteins.
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The Kinetics of Neutralization of Venezuelan Equine Encephalomyelitis Virus by Antiserum and the Reversibility of the Reaction
More LessSUMMARYThe neutralization of Venezuelan equine encephalomyelitis virus followed first-order kinetics, with the reaction rate dependent on the antibody concentration and the reaction temperature but independent of pH and virus concentration within the prescribed limits. The linear relationship obtained between the neutralization reaction rate constant (k) and antiserum dilution showed that k increased fivefold for each tenfold dilution of antiserum. The energy of activation, calculated from an Arrhenius plot of the data, was approximately 9000 cal./mole of virus. Each 10° change in temperature (Q 10) altered the k value by a factor of 1.7. In the presence of excess antibody, a small fraction of virus resisted neutralization. Neutralized virus could not be appreciably reactivated by simple dilution under physiological conditions but was dissociated at either acid or alkaline pH values. Re-neutralization of virus occurred when the environmental medium was adjusted to neutrality, indicating that reactivation was the result of dissociation and not denaturation. Neutralized virus could be attached to cell monolayers and reactivated to an infectious state by treatment at acid pH.
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The Incorporation of [3H]Thymidine, [14C]Orotic Acid, [14C]Uridine-diphosphoglucose and [14C]Glucosamine into a Post-ribosomal Fraction of Normal and Scrapie-affected Mouse Brain and Spleen
More LessSUMMARYCentrifugation of post-ribosomal supernatant fluids of brain homogenates at high speed for a prolonged period yielded a transparent pellet material. Resuspension of this pellet followed by centrifugation on a caesium chloride gradient resulted in a sharp band at a density of 1.34 g./cm.3. The band material sedimented as a single peak of approximately 5 S in the analytical ultracentrifuge and had scrapie activity. Although the position of the band and its S value are similar in normal and scrapie-affected mice there was an increased incorporation of [3H]thymidine and [14C]uridine-diphosphoglucose into the gradient fractions immediately above and into the band at a density of 1.3 to 1.34 g./cm.3 in scrapie-affected mice. Chromatography of the resuspended post-ribosomal pellet on Sepharose 4B yielded two peaks. In scrapie-affected mice, incorporation experiments showed an area between the two peaks with increased incorporation of [3H]thymidine, [14C]uridine-diphospho-glucose and [14C]glucosamine. Experiments on spleen homogenates yielded comparable results.
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Incorporation of Radioactivity from 14C-Sugars into Macromolecules in Poliovirus-infected or Guanidine-treated HeLa Cells
More LessSUMMARY14Carbon from glucose-U-14C was found to be incorporated into DNA, RNA and protein in HeLa cell cultures infected with poliovirus. This incorporation was partially inhibited by the 2nd hr of infection. The inhibition was related to the multiplicity of exposure to poliovirus and DNA was inhibited to a greater degree than RNA. In infected and normal HeLa cultures the rate of evolution of 14CO2 from glucose-1-14C was 77 times greater than from glucose-6-14C. The incorporation of 14C from these sugars into macromolecules in normal and infected cultures did not reflect this difference, thus the 14C in the macromolecules comes from the glycolytic pathway rather than the hexosemonophosphate shunt. Concentrations of guanidine inhibiting poliovirus replication also inhibit the incorporation of 14C from glucose-U-14C into DNA and RNA in normal and infected cultures. In cultures receiving both virus and guanidine, the inhibitory effects of each were not additive, suggesting that the viral inhibition of 14C incorporation requires some early step in virus replication.
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The RNA Injection Step of Bacteriophage f2 Infection
More LessSUMMARYIn this communication we describe the events occurring during the injection step in the infection of Escherichia coli Hfr cells with the RNA bacteriophage f2. The phage RNA is partially injected into the F-pilus of the Hfr cell. This step was found to be necessary for f2 RNA to block the penetration of the DNA phage f1. A cold sensitive mutant of f2 is described. It is able to inject its RNA at 41° but not at 31°.
After contact is made between the phage RNA and the F-pilus, the coat protein of the phage desorbs from the F-pilus as an empty shell, leaving the RNA free to enter the cell. In the absence of divalent metals, however, the phage RNA is unable to leave the shell. When the shell desorbs from the F-pilus, the RNA remains inside in a ribonuclease sensitive state. A small fraction of the RNA in cultures depleted of divalent metal ions remains bound to the cell. It is sensitive to ribonuclease and is removed from the cell by treatments which remove F-pili.
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Ribonucleic Acid Nucleotidyl Transferase Induced in Chick Fibroblasts after Infection with an Influenza Virus
More LessSUMMARYA RNA-dependent RNA-nucleotidyl transferase (RNA-polymerase) has been demonstrated in chick fibroblasts infected with fowl plague virus. This enzyme was not found in uninfected cells. It needed Mg2+-ions and all four nucleoside triphosphates for its activity. Pretreatment with RNase or addition of RNase prevented the incorporation of [3H]GTP into acid insoluble material. DNase had no effect. The enzyme’s activity was only slightly inhibited by actinomycin or proflavine. The incorporation of [3H]GTP could be stimulated by RNA isolated from rat liver microsomes. It was strongly inhibited by small doses of polyvinyl sulphate or dextran sulphate, and by larger amounts of DNA and protamine sulphate. The enzyme was found in the microsomal and—at a lower activity—in the nuclear fraction of infected cells. In vivo enzymic activity could not be detected until 1 hr after infection; it then increased steadily with increasing time. The rate of synthesis, however, resembled that of viral RNA synthesis. The appearance of the enzyme could be inhibited by actinomycin, actidione, or p-fluorophenylalanine. If actinomycin was added 2 hr after infection to the cells, viral RNA synthesis ceased completely at 6 hr after infection, in spite of the fact that large amounts of RNA polymerase could be then detected after homogenization.
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Volumes and issues
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Volume 105 (2024)
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Volume 104 (2023)
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Volume 103 (2022)
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Volume 102 (2021)
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Volume 101 (2020)
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Volume 100 (2019)
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Volume 99 (2018)
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Volume 98 (2017)
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Volume 97 (2016)
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Volume 96 (2015)
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Volume 95 (2014)
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Volume 94 (2013)
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Volume 93 (2012)
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Volume 92 (2011)
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Volume 91 (2010)
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Volume 90 (2009)
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Volume 89 (2008)
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Volume 87 (2006)
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Volume 86 (2005)
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Volume 85 (2004)
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Volume 84 (2003)
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Volume 82 (2001)
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Volume 81 (2000)
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Volume 80 (1999)
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Volume 79 (1998)
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Volume 78 (1997)
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Volume 77 (1996)
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Volume 76 (1995)
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Volume 75 (1994)
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Volume 74 (1993)
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Volume 73 (1992)
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Volume 72 (1991)
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Volume 71 (1990)
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Volume 70 (1989)
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Volume 69 (1988)
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Volume 68 (1987)
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Volume 67 (1986)
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Volume 66 (1985)
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Volume 65 (1984)
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Volume 64 (1983)
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Volume 62 (1982)
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Volume 60 (1982)
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Volume 57 (1981)
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Volume 56 (1981)
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Volume 55 (1981)
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Volume 54 (1981)
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Volume 53 (1981)
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Volume 52 (1981)
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Volume 51 (1980)
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Volume 50 (1980)
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Volume 49 (1980)
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Volume 48 (1980)
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Volume 47 (1980)
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Volume 46 (1980)
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Volume 45 (1979)
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Volume 44 (1979)
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Volume 43 (1979)
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Volume 42 (1979)
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Volume 41 (1978)
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Volume 40 (1978)
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Volume 39 (1978)
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Volume 38 (1978)
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Volume 37 (1977)
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Volume 36 (1977)
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Volume 35 (1977)
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Volume 34 (1977)
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Volume 33 (1976)
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Volume 32 (1976)
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Volume 31 (1976)
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Volume 30 (1976)
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Volume 29 (1975)
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Volume 28 (1975)
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Volume 27 (1975)
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Volume 25 (1974)
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Volume 23 (1974)
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Volume 21 (1973)
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Volume 18 (1973)
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Volume 16 (1972)
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Volume 15 (1972)
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Volume 14 (1972)
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Volume 13 (1971)
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Volume 11 (1971)
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Volume 10 (1971)
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Volume 9 (1970)
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Volume 8 (1970)
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Volume 7 (1970)
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Volume 6 (1970)
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Volume 5 (1969)
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Volume 4 (1969)
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Volume 3 (1968)
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Volume 2 (1968)
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Volume 1 (1967)