bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of plague vaccines by the mouse protection test
Authors: Bucklakd F. E. , Treadwell R. H. 
Published: May 2009

1. In our hands the assay of a plague vaccine, in terms of its power to protect mice against what was hoped to be a standard challenge, was found to be impracticable.2. Assay by mouse protection tests in terms of a Standard vaccine was found to be possible, but it proved to be a very time-consuming procedure and demanded the use of an almost prohibitively large number of mice for a sufficient number of replicate tests which are required to offset the variability in the method. Theoretically a single test might be adequate if the numbers of immunized mice were very large, but there are obvious limitations to the numbers of mice that can be included in a single test of this nature.3. The Ouchterlony plate technique proved to be useful in indicating the antigens present in a particular vaccine, but not on a strictly quantitative basis.4. The vaccine prepared from the virulent human strain ofP. pestiswas found to protect mice more efficiently than those prepared from avirulent strains and when the protective potency was expressed in terms of content of antigen and high molecular weight substances the vaccine prepared from the virulent culture was found to be even more potent than the Standard acetone-dried vaccine.5. The use of formalin as a preservative results in some loss of potency of a vaccine but, provided the strain ofP. pestisused for the preparation of the vaccine is highly virulent, this need not be serious and is offset by a number of advantages.
The intranasal infection of mice with Bordetella pertussis
Authors: Dolby Jean M. , Thow Doraine C. W. , Standfast A. F. B. 
Published: May 2009

Bordetella pertussis instified by the intranasal route into the lungs of mice multiply without difficulty even from small inocula, although B. pertussis is not a natural pathogen for mice and mouse to mouse infection could not be demonstrated. When the initial dose was large the bacilli multiplied until the number in the lungs reached a critical level at which the mouse died. With smaller doses the critical level was never reached; a maximum count was achieved in 10–14 days, after which the number of viable bacilli declined. These smaller doses were consistently non-lethal and the figures for the viable counts when plotted gave curves of typical shape which were called ‘sublethal curves’. The decline corresponded in time with the development of specific immunity. Growth in the lung during the first 4 days of the infection was exponential, the rate of increase in the viable count depending on the size of the inoculum; the smaller the inoculum the faster the increase. With infecting doses at about the critical level, the numbers did not increase during the first 3–4 days, and with larger doses they decreased during the first 2–4 days of infection.Antiserum given with the inoculum reduced the number of viable organisms in the lung at once. Its effect was short-lived, because after 24 hr. the lung count rose; nevertheless, the initial check on the bacteria had converted a lethal in fection into a sublethal infection.
Antigens common to Types 1 and 2 poliomyelitis viruses
Authors: Selzer Golda , Larsson K. 
Published: May 2009

During a recent epidemic of poliomyelitis three viruses isolated (one Type 1 and two Type 2) elicited both Type 1 and Type 2 CF and precipitating antibodies in the patients whilst only the homotypic neutralizing antibodies were present. These viruses inoculated into animals produced specific CF and neutralizing antibodies, but precipitating antibodies to both types were present in a significant number of animals. These findings suggest that certain polioviruses have complement-fixing and precipitating antigens common to both Type 1 and Type 2 viruses.We would like to thank our colleagues in the Virus Research Unit for their helpful advice and criticism and Dr J. Hampton (Poliomyelitis Inst., Johannesburg) for the concentrated Type 1 poliovirus vaccine.
A note on the immunogenicity of ultra-violet irradiated vaccinia virus in man
Authors: Kaplan C. , McClean D. , Vallet L. 
Published: May 2009

A preparation of vaccinia virus inactivated by ultra-violet irradiation under strictly controlled conditions, and shown to produce neutralizing antibody and resistance to challenge in rabbits, was active in only about half of 37 human volunteers. It was not, therefore, likely to be usefully immunogenic in man. In the largest single test, 15 of 25 men had unmodified primary skin reactions when challenged with living virus, although five of these had circulating antibody. On the other hand, only three of 10 men who responded to challenge with modified or negative reactions, had no circulating antibody.In man the presence of circulating antibody does not necessarily indicate resistance to infection in the skin, nor does skin immunity always indicate the presence of circulating antibody.
The pasteurization of liquid whole egg and the evaluation of the baking properties of frozen whole egg
Authors: Heller C. L. , Roberts B. C. , Amos A. J. , Smith Muriel E. , Hobbs Betty C. 
Published: May 2009

Experiments carried out by the British Egg Marketing Board in order to establish a heat treatment which would effectively pasteurize liquid whole egg are described.The results of large scale bakery trials and subsequent trade demands indicate that the recommended pasteurization treatment gives a product of a satisfactory baking performance.It is recommended that for the adequate pasteurization of whole-egg products, a temperature of 64·4°C. (148° F.) for the minimum holding time of 2·5 min. should be used.
Zone electrophoresis of enteroviruses
Authors: Polson A. , Deeks D. 
Published: May 2009

Zone electrophoresis in a sugar concentration gradient is proposed as a complementary method for the biological classification of the enteroviruses. Under standardized experimental conditions it was found that the majority of the Coxsackie A viruses and the polioviruses have a common, low electrophoretic mobility. sackie A viruses and the polioviruses have a common, low electrophoretic mobility. The impression was gained that the ECHO viruses show the highest electrophoretic mobility, though in some cases there is overlapping with the Coxsackie Bs. The mobility of both of these groups is considerably higher than that of the other two.Zone electrophoresis appears to be an excellent method for the purification of the enteroviruses prior to the production of specific precipitating antibodies.
The measurement of bacterial respiration on pig skin with micro-respirometers
Authors: Woodroffe R. C. S. 
Published: May 2009

1. The respiration of bacteria normally present in thin slices of skin taken from pig's trotters has been measured in Cruickshank micro-respirometers.2. These respirometers were originally designed to measure skin respiration in a medium including antibiotic to inhibit bacterial activity. The skin and medium was contained in a glass well. Using pig skin in a similar system without antibiotic, bacteria left the skin to grow independently in the medium. To overcome this difficulty polythene cups were made with an inner compartment for the tissue without medium and an outer compartment for water which provided a humid atmosphere.3. Using polythene cups without medium the skin respiration was neglible, bacterial respiration was measured in situ and correlation between oxygen uptake and bacterial counts was obtained. This correlation was valid within experiments only.4. Respiration of skin samples taken from adjacent areas of pig's trotter was similar, but there was large variation between samples from different trotters.5. Respiration due to bacteria increased rapidly for 6–9 hr., followed by a slower increase. This may be due to a limited food supply or to a state of equilibrium.
A respirometer technique for estimating germicidal activity on skin
Authors: Woodroffe R. C. S. 
Published: May 2009

1. A technique for measuring the antibacterial activity of germicides on pig skin in micro-respirometers has been described.2. Using this technique the activity of the following germicides has been estimated: 2,2-dihydroxy, 3,5,6,3′,5′,6′-hexachlorodiphenylmethane, 3,4,4′-trichlorocarbanilide, 3,5,4′tribromosalicylanilide, 2,2′-thiobis (4,6-dichlorophenol), Irgasan CF3*, 3,5,3′,4′-tetrachlorosalicylanilide.3. The results obtained have been discussed in relation to hand-washing test results (Hurstet al.1960).
Factors affecting the growth of virus of foot-and-mouth disease on surviving explants of bovine tongue epithelium
Authors: Morrow A. W , Buckley L. S 
Published: May 2009

A simple, laboratory scale, stirred system has been developed to examine conditions of culture necessary for optimum return of infective virus from explants of surviving bovine tongue epithelium, with particular bias towards large-scale procedures.Control of hydrogen-ion concentration and aeration of the culture are emphasized.The authors wish to thank Dr I. A. Galloway and Dr J. B. Brooksby for their helpful advice in preparing this paper, Mrs J. Lansley for her untiring technical assistance and Mr J. Goodridge who constructed the culture apparatus.
The site of specific substances in capsulated organisms
Authors: Barber Cella 
Published: May 2009

Applying a method of selective separation of the specific high polymers the intracellular site of the specific substance in the Copenhagen strain of Pneumococcus Type II was demonstrated, by electron microscopy; the specific polymeric material assumed to form the capsule is situated within the bacterial cell and the electron density of this material is sufficiently high to permit its detection.The possibility of obtaining electron micrographs of the polymeric substances as contained in the cells or after their diffusion into the medium or when secreted as slime, suggests that the current concept of the capsules as the site of the specific substances may have to be reviewed.The electron micrographs were made by Dr A. Petrovici to whom I express my thanks.
Physical and serological investigation of Rift Valley fever antigens
Authors: Levitt Julia , Polson A. 
Published: May 2009

1. Extracts containing non-infective soluble antigens have been prepared from the tissues of mice infected with a pantropic or any of three neurotropic strains of Rift Valley fever virus. The antigens were detectable by complement-fixation and gel-precipitin tests using antisera prepared in mice.2. The extracts appeared to contain at least two antigens separable by electrophoresis and distinguishable by Ouchterlony tests. The faster migrating minor antigen occurs sparsely and was not further examined.3. No distinction, physical or immunological, was observed between the major antigen derived from the four strains.4. In gel diffusion-filtration experiments with granulated 7 % agarose, the major antigen appeared to be polydisperse containing particles with diffusion rates ranging from at least as low as that ofBurnupena cinctahaemocyanin to almost as high as that of haemoglobin.5. Centrifugal analysis indicated the presence of particles having sedimentation constants of about 8, 29 and greater than 100 Svedberg units. These particles have a density of about 1·27 g./ml. If all the particles of the major antigen are spherical, with a density of 1·27 g./ml., the three size groups have diameters of about 7–8, 14 and < 26 mμ.6. The diffusion coefficient of the smallest particle was estimated to be 6·06x 10−7cm.2/sec. corresponding to a sphere 7 mμ in diameter, or 4·78 x 10−7cm.2/ corresponding to a sphere 9 mμ in diameter depending on which of two values for the diffusion coefficient of mouse γ-globulin is used in the calculation.7. In density gradient zone electrophoresis at pH 8·6, the principal antigen migrated at about the same rate as haemoglobin and appreciably slower than the virus. The authors are indebted to Prof. A. Kipps for his continued interest in this work, and to Dr T. H. Mead for valuable criticism of this paper. This investigation was supported in part by a Public Health Service research grant Al 04044–02 from the National Institute of Health, Bethesda, U.S.A.
Simultaneous active and passive immunization of guinea-pigs against tetanus
Authors: Smith J. W. G. 
Published: May 2009

1. Simultaneous active and passive immunization of guinea-pigs using tetanus toxoid adsorbed on to aluminium hydroxide produced a higher antitoxin response than simultaneous immunization using plain toxoid. The response was also better than that produced by plain toxoid alone.2. A 24 hr. interval between the injection of plain toxoid and the subsequent injection of antitoxin gave no better results than when toxoid and antitoxin were given at the same time.3. The response to simultaneous immunization, using adsorbed toxoid, of guinea-pigs sensitized to horse serum, was superior in the first 6 weeks to that of guinea-pigs which had not been sensitized.4. The suggestion that simultaneous active and passive immunization of man should be performed with adsorbed toxoid rather than plain toxoid is supported by these results.
A complement fixation technique for the quantitative measurement of antigenic differences between strains of the virus of foot-and-mouth disease
Authors: Davie John 
Published: May 2009

1. A complement fixation test has been developed to measure the minor antigenic differences which occur between strains of the virus of foot-and-mouth disease of the same immunological type.2. Strain-specific sera were prepared from each of the virus strains examined and then titrated with each of the antigens.3. The amounts of complement fixed in each reaction were measured in the region of maximal fixation where the antigen and antibody were present in optimal proportions.4. Heterologous antigen-antibody reactions were compared with the homologous reaction in each test and expressed as cross-fixation ratios.5. Pairs of antigens could then be compared by taking the product of their cross-fixation ratios one with the other. The values of cross-fixation product so obtained ranged from 1·0 between identical strains to 0·01 between strains of different immunological type.6. Strains of virus which exhibit cross-fixation products of 0·5 or more with one another have been classified within subtype groups.I wish to acknowledge the guidance and encouragement of Dr J. B. Brooksby, Director of the Animal Virus Research Institute, Pirbright, and the technical assistance of Mr E. Scoates.
The development of skin resistance and hypersensitivity following inactivated vaccinia virus vaccines in rabbits
Authors: McNeill T. A. 
Published: May 2009

A study was made of the development of skin resistance and delayed hyper-sensitivity to vaccinia virus after immunization with inactivated vaccinia virus in rabbits. These vaccines are shown to increase skin resistance, and it is also shown that the development of this resistance is dependent upon the virus content of the vaccine. Skin resistance is shown to be related to the titre of circulating antibody rather than to the degree of delayed hypersensitivity. Possible reasons for conflicting reports in the literature on this subject are discussed.An unusual skin reaction was seen in some animals when challenged with live virus after immunization with inactivated vaccine. The nature of these reactions is discussed.
Streptococcal infection in young pigs. II. Epidemiology and experimental production of the disease
Authors: Elliott S. D. , Alexander T. J. L. , Thomas J. H. 
Published: May 2009

1. In streptococcal infection of piglets the causative agent (PM streptococcus) was isolated from the throats of a high proportion of infected animals and from their apparently healthy litter-mates.2. The PM streptococcus was isolated from the noses of three out of forty-three normal sows. In one sow the streptococcus was also isolated from the throat.3. Bacteriaemia was induced in piglets up to the age of 17 days by inoculating into the nose and throat broth cultures of the PM streptococcus. Blood cultures were usually positive within 24 hr., and secondary involvement of the joints and meninges frequently occurred during the ensuing few days.4. Serum taken from piglets 5 weeks after experimental infection and administered subcutaneously protected susceptible piglets against subsequent infection with PM streptococci.5. The possibility of preventing streptococcal infection in piglets by active immunization of the sow is discussed.
Further studies with quadruple vaccine
Authors: Dane David S. , Haire Margaret , Dick George , Briggs E. Moya , Connor T. J. 
Published: May 2009

Reactions to the pertussis component of the original commercial batches of quadruple vaccine against poliomyelitis, diphtheria, tetanus and pertussis (Quadrilin, Glaxo Laboratories) gave some cause for concern. Severe reactions were found to be more common in infants under 6 months of age than in older infants.A modified quadruple vaccine, which has been used in N. Ireland since October 1964, was found to give rise to significantly fewer and milder reactions. This vaccine when given in three doses separated by intervals of 6–9 weeks and 6 months to fifty-eight infants most of whom were 6–7 months of age at the start of immunization was found to give a satisfactory immunological response.
Immunogenicity of experimental trachoma vaccines in baboons: I. Experimental methods, and preliminary tests with vaccines prepared in chick embryos and in HeLa cells
Authors: Collier L. H. , Blyth W. A. 
Published: May 2009

Parallel titrations of a strain of trachoma (MRC–221) and one of inclusion conjunctivitis (MRC–4) in the baboon conjunctiva and in chick embryos suggest that ten to twenty 50% egg infective doses are equivalent to one 50% baboon infective dose; but that at least 1000 egg infective doses are needed to induce moderate or severe infections in all of a given number of baboons.For vaccine experiments in baboons, a system of scoring physical signs and presence of inclusion bodies was devised; the significance of differences in vaccinated and control animals in their response to conjunctival challenge was determined by analysis of variance. An aqueous suspension of live MRC–4 grown in the yolk sac was given as two subcutaneous doses and one intravenous dose at weekly intervals, and protected all of six baboons challenged with the homologous strain; three similarly spaced subcutaneous doses were less effective. The immunity induced by this vaccine waned considerably during the ensuing 15 months. Vaccine prepared from a live ‘fast-killing’ variant of MRC–4 grown in HeLa cells was less effective than MRC–4 itself in protecting baboons against infection with the parent strain.Although both yolk sac and HeLa cell vaccines induced the formation of antibody fixing complement with trachoma group antigen, the serum titres in individual animals at the time of challenge were unrelated to the degree of protection; during a 15 month observation period there were pronounced falls in the titres of antibody induced either by vaccination or by challenge with egg-grown TRIC agent.We wish to thank Dr I. Sutherland (M.R.C. Statistical Research Unit) for his helpful advice during the early stages of this work. We are also greatly indebted to Mr P. Avis (Pfizer Ltd.) for his advice and for undertaking the statistical computations; and to Miss Anne Smith and Miss Pay Storey (M.R.C. Trachoma Research Unit) for doing the complement fixation tests.
The inhibition of growth of vaccinia and cowpox viruses in RK 13 cells
Authors: Baxby Derrick , Rondle C. J. M. 
Published: May 2009

SUMMARYThe growth of vaccinia and cowpox in RK13 cells was studied by measurement of infective virus production, gel diffusion and haemagglutination. The effects of virus growth inhibitors on the normal course of infection were then followed. Although the results with the two viruses were essentially similar some differences were detected between them. Inhibitors of DNA synthesis permitted production of many virus-specific soluble antigens. Compounds which inhibit DNA function and compounds that affected energy-yielding reactions had more dramatic effects. The different results obtained suggested that the synthesis of virus-specific materials was sequential and a possible part of the sequence is suggested.
Age susceptibility and excretion ofSalmonella typhimuriumin calves
Authors: Robinson R. A. , Loken K. I. 
Published: May 2009

SUMMARYTwo groups of calves were dosed orally with 104, 105, and 106S. typhimuriumat approximately 2 days of age and at 14–21 days of age. No obvious clinical signs were observed with this strain, but younger calves excreted the salmonellas in the faeces for longer periods than older animals. The younger animals also excreted more salmonellas per gram of faeces in the first week following dosing. These observations may explain why salmonella cross-infection is likely to occur where very young calves are congregated. Following cessation of excretion of salmonellas in the faeces and subsequent slaughter of calves, examination of all the mesenteric, caecal, and colic lymph nodes showed these to be the most useful sites for recovery of salmonellas.Provided good nutrition and hygienic conditions prevail, calves retained on their farm of origin for longer periods are more likely to recover from neonatal salmonella infections.
Evidence for a two-stage model of microbial infection
Authors: Meynell G. G. , Maw Joan 
Published: May 2009

SUMMARYColony counts on mice given the same number ofSalmonellaalways differ considerably. However, the standard error of the mean log count does not increase after the first 1·5 hr. of infection until the 8th or 10th day. These infections therefore appear to pass through an initial stage lasting a few hours, in which a varying proportion of the inoculum is killed, followed by a prolonged second stage in which the scatter in individual colony counts remains constant.
Inhibition by pyrimidine analogues of the synthesis of folic acid by trachoma agents
Authors: Reeve P. , Taverne Janice , Bushby S. R. M. 
Published: May 2009

SUMMARYTrimethoprim, a 2,4-diaminopyrimidine derivative which inhibits the growth of some bacteria by interfering with folic acid synthesis, inhibited the growth of several strains of the trachoma agent. Inhibition was most clearly demonstrated by measuring prolongation of mean death time of groups of chick embryos inoculated with a single lethal dose of agent. Over a certain range, prolongation was proportional to the logarithm of concentration of inhibitor; higher concentrations were toxic for the embryo. On a weight basis, trimethoprim was not as active as sulphafurazole. Inoculation in conjunction with sulphafurazole resulted in slight potentiation of activity. A related pyrimidine derivative, the antimalarial drug pyrimethamine, also significantly inhibited the growth of one strain of trachoma.In cell culture, trimethoprim decreased the number of inclusions formed by a suspension of the trachoma agent and induced morphological changes in the inclusions similar to those caused by sulphafurazole.Inhibition of the growth of the trachoma agent in the chick embryo was reversed by leucovorin calcium. It is concluded that, as with bacteria, the drug acts by blocking the folio acid cycle and that the trachoma agent most probably contains a dihydrofolate reductase.