bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some factors affecting the viability of freeze-thawed T4 bacteriophage
Authors: Steele P. R. M. , Davies J. D. , Greaves R. I. N. 
Published: May 2009

SUMMARYSome effects of freeze-thawing on the T 4 bacteriophage have been studied. The results indicated that most of the inactivation of rapidly thawed samples was due to osmotic damage, whereas inactivation of slowly thawed samples appeared to be correlated with the eutectic temperature of the suspending medium. Peptone significantly increased the survival of slowly thawed T 4 phage. The particular constituents of peptone largely responsible for this protection were separated as two distinct peptide fractions, using G 25 Sephadex.This work has been supported in part by grants from the Medical Research Council and the Office of Naval Research under contract F61052–68-C-0041.
Salmonella and Arizona in reptiles and man in Western Australia
Authors: Iveson J. B. , Mackay-Scollay E. M. , Bamford V. 
Published: May 2009

SUMMARY1. Ninety-seven (83.6%) of 116 reptiles, comprising 70 lizards, 40 snakes, 4 tortoises and 2 crocodiles, yielded isolations of organisms in the Salmonella and/or Arizona groups.2. The reptiles were captive or free-ranging; the former were drawn from all states of mainland Australia, while the latter were from West Australia only.3. The relative prominence ofSalmonellaserotypes containing numerically highsomatic antigens, the finding of newserotypes, of multiple infections, and of strains in subgenera II and III was remarked.4. The lack of evidence of differences in the serotypes isolated from captive or wild reptiles (except for the isolation ofS. typhimuriumin creatures closely associated with man and his domestic fauna), and the apparent absence of a specific geographical distribution of serotypes in reptiles, lent support to the con clusion that reptiles provide a natural reservoir forSalmonellaand Arizona strains in Australia. The possible spill-over to man, his domestic animals and his food stuffs is discussed.It is a pleasure to record our indebtedness to Dr Joan Taylor for her continuous interest and support in providing confirmation and identification of manySalmonellaserotypes; to Dr W. H. Ewing and later Dr R. Rhode for serotyping the Arizona strains; to Dr G. M. Storr, Curator of Reptiles in the Museum of Western Australia, for identifying the reptiles and to Dr W. S. Davidson, Commissioner of Public Health, Western Australia, for permission to publish.
The effect of the tapeworm Hymenolepis nana on immunity to tuberculosis in mice
Authors: Olds R. J. 
Published: May 2009

SUMMARYMice which carried the tapeworm Hymenolepis nana gave anomalous results when they were infected with tubercle bacilli. Males died earlier than females. The cause of death in some was intussusception or acute enteritis. More tapeworm eggs were excreted in the faeces of male mice, and, for each sex, egg counts were higher in BCG-vaccinated animals.This work forms part of the studies on immunity to tuberculosis for a Ph.D. thesis, and was carried out while I was in receipt of a Harrison-Watson Studentship of Clare College and a Welcome Fellowship of the Animal Health Trust.
Cross-contamination by cooked-meat slicing machines and cleaning cloths
Authors: Gilbert R. J. 
Published: May 2009

SUMMARYIn view of recent food-borne outbreaks of salmonella infection in which cooked-meat slicing machines have been implicated in the spread of organisms from contaminated meat products to other meats, experiments have been made to provide laboratory evidence that a contaminated slicing machine will easily cross-contaminate other products passing through it. Chopped pork inoculated with coagulase-positive staphylococci was cut on a slicing machine; staphylococci were isolated up to the 41st slice of various cooked meats cut on the same machine. The experiments were repeated withSalmonella oranienburg; this serotype was isolated up to the 31st slice of various cooked meats cut on the same machine, and from pieces of damp cloth wiped over the gravity feed, knife centre disk and cutting blade.The importance of efficient and regular cleaning of slicing machines with hot water containing detergent/disinfectant, or detergent followed by disinfectant, applied with clean cloths or preferably disposable paper, is stressed.I thank Dr Betty C. Hobbs, Director of the Food Hygiene Laboratory, and Dr J. C. Kelsey, Administrative Director of the Central Public Health Laboratory, for their help throughout the work and the compilation of the paper.
Some rodenticidal properties of coumatetralyl
Authors: Greaves J. H. , Ayres Priscilla 
Published: May 2009

SUMMARYThe toxicity and palatability of coumatetralyl (3-(α-tetralyl)-4-hydroxycoumarin) to rats (Rattus norvegicus Berk.) were investigated in the laboratory by means of feeding tests. Animals resistant to warfarin (3-(α-acetonylbenzyl)-4-hydroxy-coumarin) and warfarin-resistant rats from infestations refractory to coumatetralyl, as well as non-resistant animals, were employed in the tests.Medium oatmeal containing a concentration of 0·1% coumatetralyl was not markedly less palatable than the same food unpoisoned. In comparison warfarin at 0·05% but not at 0·025% was significantly less readily eaten than the plain food. Coumatetralyl at 0·05% and 0·005% was about as toxic as 0·005% warfarin is reported to be to non-resistant rats. Warfarin-resistant rats were significantly less susceptible to coumatetralyl than were non-resistant rats. Warfarin-resistant rats from an infestation refractory to coumatetralyl were significantly less susceptible to coumatetralyl than were animals from other sources.It is considered that coumatetralyl at concentrations of the order of 0·05% in bait would be a good alternative to warfarin against non-resistant rats. While it would be expected that, at this concentration, coumatetralyl would often give good results against warfarin-resistant infestations, this use might eventually produce an increase in the incidence of resistance to both anticoagulants.We thank Baywood Chemicals Ltd., for supplying the coumatetralyl used in this work. We are also indebted to several colleagues for supplying wild rats and information on field investigations and to Messrs G. Snell and P. Romer for technical assistance.
Overlap and the errors of plaque counting: I. The overlap biases of observed counts and their correction
Authors: Howes D. W. 
Published: May 2009

SUMMARYThe number of plaque-forming units is underestimated if plaques overlap. A simple model was developed to account for this bias, and tested by an extensive experimental analysis. It is shown that models of this type are inadequate, but can be modified to give objective methods for setting limits to the acceptable counting range, and for correcting the overlap bias of observed counts which fall within this range.Where overlapping of plaques is a significant source of error, these methods will improve the efficiency of plaque assays and will render the statistical analysis of counting data more reliable.
Overlap and the errors of plaque counting: II. The bias of the variance and the concealment of errors
Authors: Howes D. W. , de St Groth S. Fazekas 
Published: May 2009

SUMMARYThe overlapping of plaques compresses their distributions and reduces observed variances. For a given distribution the reduction of the variance is substantially larger than that of the mean. To derive the error of a plaque assay from the assumption that the variance equals the mean may therefore lead to serious over-estimation of the precision of the assay.Procedures for estimating the true error of plaque assays are developed, and their use is illustrated on experimental material.
Transfer areas and clean zones in operating suites
Authors: Ayliffe G. A. J. , Babb J. R. , Collins B. J. , Lowbury E. J. L. 
Published: May 2009

SUMMARYThe value of clean zones and of transfer areas in operating suites was assessed by comparisons of the amounts of contamination on floors, trolleys and footwear in suites with and without a clean zone and a transfer area; counts of Clostridium welchii were used as an index of bacterial contamination introduced into the aseptic zone from outside.The mean counts of Cl. welchii on contact plates from the wheels of trolleys used to convey patients from wards to the operating suite (67·9 ± 7·68 per plate) were significantly higher than those from theatre trolleys (i.e. those used only inside a theatre suite provided with a transfer area) (3·13 ± 0·47 per plate); mean counts of total bacteria were only slightly lower on the wheels of theatre trolleys than on those of hospital trolleys. Other surfaces of hospital trolleys showed counts similar to those found on theatre trolleys.Contact plates from floors showed significantly lower counts of Cl. welchii in the aseptic zone and the clean zone than in the hospital corridor, the protective zone and (when present) the transfer area.The mean counts per 100 cm2 of Cl. welchii were approximately the same on the floor of a theatre with a clean zone and a transfer area (0·83) as in one with a clean zone but no transfer area (0·5). Counts of total bacteria were higher in the latter. A suite with no clean zone or transfer area showed a higher mean count of Cl. welchii on contact plates from the aseptic zone (operating theatre) (20·5 ± 12·33 per 100 cm2). These higher levels of contamination were due to sporadic high counts of Cl. welchii found near the door of the theatre with no clean zone; in another theatre with no clean zone the level of Cl. welchii on the floor was not higher than that in the theatres with clean zones.Theatres with plenum ventilation had lower mean counts of airborne Cl. welchii than those ventilated by windows: there was no significant difference in the levels of Cl. welchii on the floors of theatres with the two forms of ventilation.On sampling with contact plates, theatre footwear yielded fewer total organisms, Staphylococcus aureus and Cl. welchii than outdoor shoes removed before entering the clean zone.The hygienic value of transfer areas and clean zones is discussed. Bacteriological support could not be obtained for the former, but the latter appeared to contribute something to the cleanliness of the theatre by preventing heavy sporadic contamination.We wish to thank Mr M. Wilkins for valuable assistance, the staff of the operating theatres for their co-operation and Alne Engineering Limited, 57 High Street, Henley-in-Arden, Solihull, for supplying disposable contact plates.
Strontium chloride and strontium selenite enrichment broth media in the isolation ofSalmonella
Authors: Iveson J. B. , Mackay-Scollay E. M. 
Published: May 2009

Two new media, strontium chloride and strontium selenite broths, are described for the enrichment culture ofSalmonellafrom human and animal material.In comparative trials, strontium chloride was found to be comparable to Rappaport medium for the recovery of a wide range ofSalmonellaserotypes from human faeces and sewage, and from pig faeces and glands. Both were superior to selenite F medium.Strontium selenite was found to be superior to selenite F in the recovery ofS. typhifrom human faeces and sewage.We are greatly indebted to Mr M. H. Lello for preparing the samples of strontium selenite used in the investigation and for allowing us to publish the notes on his method of preparing the substance.Our thanks are due to Pro. C. T. Huang of Hong Kong for sending samples of faeces from typhoid cases under his care; and to Dr Joan Taylor for her continuing help in confirming or identifying the serotypes of salmonella isolated.We thank Dr W. S. Davidson, Commissioner of Public Health, Western Australia, for permission to publish.
Pantothenate-requiring dwarf colony variants ofStaphylococcus aureusas the etiological agent in bovine mastitis
Authors: Sompolinsky D. , Gluskin I. , Ziv G. 
Published: May 2009

SUMMARYIn a herd affected with bovine mastitis, dwarf colony variants ofStaphylococcus aureus, auxotrophic for Ca-pantothenate, were isolated from the milk of four cows with mastitis. From one of these cows, a dwarf variant with an unknown metabolic disorder was isolated during the same period. Infections with auxo trophic staphylococci were always chronic and proved to be refractory to anti biotic treatment, though the causative micro-organism was highly susceptible to the drugs used as judged byin vitrotests.The authors acknowledge with appreciation the skilful help of Miss Nili Abramova.
Control of cross-infection in an intensive care unit
Authors: Harris D. M. , Orwin J. M. , Colquhoun J. , Schroeder H. G. 
Published: May 2009

SUMMARYIn a survey undertaken in an intensive care unit, coliform bacilli were found to be responsible for most infections,Pseudomonas aeruginosaand Staphylococcus aureus being isolated much less frequently. Tracheostomy or endotracheal intubation predisposed to infection, but in our experience intermittent positive pressure ventilation did not significantly affect its incidence. Little cross-infection has occurred, and it has never been possible to incriminate the ventilators in its transmission.We gratefully acknowledge the assistance we have received from colleagues in the Intensive Therapy Unit and the Department of Bacteriology during the course of this investigation.
The influence of antigenic variation on influenza A2 epidemics
Authors: Pereira Marguerite S. , Chakraverty Pratima , Pane A. R. , Fletcher W. B. 
Published: May 2009

SUMMARYThe antigenic variation of influenza A 2 virus and the antibody present in the population to different variants are described and related to the occurrence of epidemics of influenza in England since 1957.
A comparative study of methods for the diagnosis of respiratory virus infections in childhood
Authors: Sturdy Patricia M. , McQuillin Joyce , Gardner P. S. 
Published: May 2009

SUMMARYNasopharyngeal secretions and cough/nasal swabs were taken from 111 children admitted to hospital in Newcastle upon Tyne with acute lower respiratory disease. A comparison was made between nasopharyngeal secretions and cough/nasal swabs as material for isolation of viruses in tissue culture. These results were, in turn, compared with those obtained by applying a fluorescent antibody technique to the exfoliated cells in the nasopharyngeal secretions for the rapid diagnosis of respiratory syncytial virus infection.More viruses were isolated in tissue culture from nasopharyngeal secretion than from cough/nasal swabs. Further evidence for the superiority of nasopharyngeal secretions was obtained by comparing the virus isolations in the laboratory in 1967 with those in 1968. Respiratory syncytial virus was not only isolated more often but more quickly in tissue culture inoculated with nasopharyngeal secretions.The fluorescent antibody technique not only provided a diagnosis on the patient's day of admission in 95% of those infected with respiratory syncytial virus but also proved to be as sensitive as the culture of nasopharyngeal secretions and considerably more sensitive than the culture of cough/nasal swabs for the diagnosis of respiratory syncytial virus infection.We wish to acknowledge the invaluable help given us by consultants, medical officers, ward sisters and their staff in the paediatric wards of the Child Health Department. We also wish to thank the technical staff in the Department of Virology for their aid.
Some factors affecting the viability of freeze-thawed T4 bacteriophage
Authors: Steele P. R. M. , Davies J. D. , Greaves R. I. N. 
Published: May 2009

SUMMARYThe effects of various salts on the viabifity of T4 and T4 Bo phages during freezing and thawing have been studied. The effectiveness of different salts in causing inactivation or protection of phage during freeze—thawing was of the same order as has been observed for their effects on the conformational stability of macromolecules. There were two important contributory factors causing inactivation of phage during freeze—thawing: (i) concentration of solutes during freezing, and (ii) lowering the temperature, without change in salt concentration.The viability of phage following storage at subzero temperatures was dependent on the storage temperature, the species of ions in the suspending medium and the initial salt concentration. Viability was greatest when phage had been initially suspended in dilute solutions.Survival of T4 Bo phage, following cooling to subzero temperatures and rewarming, was greater in D2O solutions than in H2O solutions.It was found that 20% glycerol completely protected against inactivation of T4 Bo phage, suspended in 3·5 molal NaBr, which were cooled to subzero temperatures and rewarmed in the absence of ice. Without added glycerol the viability of T4 Bo phage suspended in 3·5 molal NaBr, which were cooled to −20° C and rewarmed was less than 1%. This protective effect of glycerol is in contradiction to the accepted views of its mode of action in prevention of freezing injury.This work has been supported in part by grants from the Medical Research Council and the Office of Naval Research under contract F 61052–68-C-0041.
Bactericidal properties of Tego 103 S and Tego 103 G
Authors: Kuipers J. S. , Dankert J. 
Published: May 2009

SUMMARYThe bactericidal activity of Tego 103S was compared with that of chlorhexidine in ethanol, and Tego 103G with Halamid. The activity was determined on Pseudomonas aeruginosa, Staphylococcus aureus and Achromobacter anitratus by various methods. Tego 103S in 1% solution was less active than chlorhexidine 0·5% in 70% ethanol, and Tego 103 G in 1% solution was less active than Halamid 0·3 %. The presence of serum did not noticeably influence the activity of the Tego preparations.
Studies on the serological relationships between avian pox, sheep pox, goat pox and vaccinia viruses
Authors: Uppal P. K. , Nilakantan P. R. 
Published: May 2009

SUMMARYBy using neutralization, complement fixation and immunogel-diffusion tests, it has been demonstrated that cross-reactions occur between various avian pox viruses and between sheep pox and goat pox viruses. No such reactions were demonstrated between avian pox viruses and vaccinia virus or between avian pox and sheep pox and goat pox viruses. Furthermore, no serological relationship was demonstrable between vaccinia virus and sheep pox and goat pox viruses.
Vaccination against Hong Kong influenza in Britain, 1968–9: A report to the Medical Research Council Committee on Influenza and other Respiratory Virus Vaccines
Authors: Tyrrell D. A. J. , Buckland Rosemary , Rubenstein D. , Sharpe D. M. 
Published: May 2009

SUMMARYStudies of the effect of Hong Kong (HK) influenza vaccine were made in adults and children in Great Britain during 1968 and 1969. The vaccines were administered intramuscularly and also by intranasal spray. The serum antibody response was studied in 284 subjects. Most developed rising titres to vaccine given intramuscularly and few to vaccine given intranasally. Deoxycholate-split vaccine was as potent as conventional whole virus vaccine. Antibody titres were maintained for months. Over 4000 subjects in factories, offices and schools were observed during the epidemic. The incidence of disease was not significantly reduced by either form of vaccination. A survey was made of epidemics in boarding schools in which some of the pupils had been vaccinated, in six with commercial polyvalent vaccine and in five with HK; there was a lower incidence of influenza in two schools vaccinated 2 or 4 weeks earlier with HK vaccine.
A comparison of monovalent Hong Kong influenza virus vaccine with vaccines containing only pre-1968 Asian strains in adult volunteers: A report to the Medical Research Council Committee on Influenza and other Respiratory Virus Vaccines
Authors: Hobson D. , Baker F. A. , Chivers C. P. , Reed Sylvia E. , Sharp D. 
Published: May 2009

SUMMARYA total of 1601 adult industrial workers were vaccinated with either monovalent inactivated vaccine of the Hong Kong strain of influenza A virus, or with polyvalent vaccine containing only pre-1968 Asian viruses. Serological investigations on a random sample of volunteers showed that 53/56 (95 %) given Hong Kong vaccine developed a significant rise in specific haemagglutination-inhibiting antibody; final titres were 1/48 or greater in 39 (70%) and the GMT (geometric mean titre) was 96·5. After polyvalent Asian vaccine, 40/67 (60%) also produced antibody against Hong Kong virus, but only 21 (31 %) had final titres of 1/48 or above, and the GMT rose only to 14·1. An intranasal spray of the Hong Kong vaccine in addition to injected Asian vaccine gave no additional increase in antibody.Each type of vaccine stimulated a recall of pre-existing antibody against Asian viruses. The possible significance of heterologous responses to the two vaccines is discussed.The incidence of clinical influenza in the trial population was sporadic, and the infection rates were too low to allow any accurate estimate of the protective efficiency of the two vaccines.
Temperate bacteriophages ofEscherichia coliO119:B14
Authors: Kasatiya S. S. 
Published: May 2009

SUMMARYLysogeny was detected in 98·8 % of the 343Escherichia coliO119: B14 strains. A suitable indicator strainE. coliKS was selected to demonstrate the presence of temperate phages in this serotype. A great diversity in the temperate population was observed based on their lytic patterns and neutralization studies. No definite relationship could be established between the biochemical reactions and the flagellar antigens of the lysogenic strain and its temperate phage though some temperate phages released byE. coliO119:B14 strains with certain flagellar antigens did give specific lytic patterns and were serologically identical. Lysogenic strains, which did not release temperate phages spontaneously, were u.v. in-ductible. Cross-reactions with lysogenized colonies which were immune to corresponding phages also confirmed diversity of temperate phages inE. coliO119: B 14.
Differentiation of the serological response toYersinia enterocoliticaandBrucella abortusin cattle
Authors: Corbel M. J. , Cullen G. A. 
Published: May 2009

SUMMARYThe serological responses of cattle to inoculation withBrucella abortusandYersinia enterocoliticatype IX were compared. Complete cross-reactions were found in serum agglutination, antiglobulin, complement fixation and Rose Bengal plate tests. The cross-reaction betweenBr. abortusandY. enterocoliticaIX was confirmed by immunodiffusion tests. Although antibodies specific for each organism could also be detected by immunodiffusion tests with high titre rabbit or bovine sera, these tests were insufficiently sensitive for routine diagnostic use.A quantitative Rose Bengal plate test, using Rose Bengal stainedBr. abortusandY. enterocoliticaIX, was developed which enabled the antibody responses to the two organisms to be differentiated. The specificity of this test was confirmed by cross-absorption experiments and its sensitivity was sufficient to permit evaluation of all bovine sera giving positive reactions to the serum agglutination test.
The laboratory transmission of Coxsackie A6 virus by mosquitoes
Authors: Maguire T. 
Published: May 2009

SUMMARYCoxsackie A 6 virus, strain V 29, originally isolated from Aedes polynesiensis in Fiji, was found to survive in A. australis for 5 days after intrathoracic injection and for 6 days after feeding on viraemic mice, and in Culiseta tonnoiri for 8 days after feeding.The virus level in both fed and injected mosquitoes fell steadily after infection and never exceeded the original level.No virus transmission was obtained in 46 successful second feedings on days 10–14 with A. australis, but three transmissions were obtained with C. tonnoiri, two on day 10 and one on day 13, from 12 successful second feedings.