Search PubMed⌕ Search

Biomedical subjects

A S Beare

Publications and source records attributed to A S Beare.

At least 37 records · Page 2Linked to original sources
PubMed1975

A single radial haemolysis technique for the measurement of influenza antibody.

A single radial haemolysis in geltechnique has been developed for the detection and measurement of antibody to influenza haemagglutinin. The methold combines the sensitivity of haemagglutination-inhibition with the accuracy of single radial diffusion. It is simple, quick, reproducible, does not require purified or concentrated virus, and is unaffected by non-specific inhibitors. The method is particularly suitable for the routine screening of large numbers of serum samples, and may have application also to viruses other than the influenza group.

Animals↗
PubMed1975

Glutamate dehydrogenase specific activity and cephalosporin C synthesis in the M8650 series of Cephalosporium acremonium mutants.

Conditions for the accurate measure of glutamic dehydrogenase (GDH) from Cephalosporium acremonium were determined. K(m) values for alpha-ketoglutarate and ammonium ion were 7 and 15 mM, respectively. The half-saturation for reduced nicotinamide adenine dinucleotide phosphate was 5 muM. Reduced nicotinamide adenine dinucleotide did not serve as a cofactor for the enzyme. The specific activity of GDH was measured in six mutants of C. acremonium which varied in their ability to synthesize cephalosporin C. The mutants represented two separately derived lines, A and B. The four mutants in line B were characterized by a derepression of the GDH upon entry into stationary phase. The two mutants in line A were characterized by repressed levels of GDH during the same period. Both lines exhibited high GDH activity early in their fermentations, but activity decreased during the period of active cell growth. Cytochrome c concentrations followed the same pattern as total soluble intracellular protein. Line A mutants were low in cephalosporin C productivity and line B encompassed low, intermediate, and high productivity mutants. The relative frequency of yield improvements in line A and B indicate that the altered regulation pattern for GDH in line B may have removed a nitrogen limitation for cephalosporin C synthesis.

Acremonium↗
PubMed1975

Myxoviruses.

Myxoviruses can be divided into 2 groups, orthomyxoviruses and paramyxoviruses. the former comprise the influenza group which is subdivided into types A,B and C. Influenza B and C are purely human pathogens but influenza A, which includes a large number of antigenic subtypes, occurs in nature in pigs, horses, birds and man. All influenza A viruses irrespective of origin are chemically, biologically and genetically related. The epidemics which they cause are curious and puzzling and are an important cause of morbidity. Paramyxoviruses consist of human and animal parainfluenza viruses. The former comprise parainfluenza types 1,2,3 and 4 and mumps viruses, and, rather less certainly, measles and respiratory syncytial virus. The main animal paramyxoviruses are parainfluenza 3 (agent of shipping fever) in cattle; NDV (cause of fowl pest) and Yucaipavirus in birds; Sendai and PVM in mice; Nariva virus in rodents; possibly bovinerespiratory syncytial virus; and SV5 and SV41 in monkeys. The viruses and their place in nature will be reviewed.

Animals↗
PubMed1974

Use of single radial immunodiffusion test for serological studies in volunteers inoculated with live attenuated influenza virus.

Pre- and post-vaccination serum samples from 278 volunteers, who were given live influenza vaccines, were tested by haemagglutination inhibition (HI) and single radial immunodiffusion tests(SRDT) for antibody to influenza A/Hong Kong/1/68 (H3N2) virus envelope antigens. Those with high antibody titres detected in both tests were less frequently infected, and 85% of the 159 infected showed rises by HI and 70% by SRDT. Similarly, 69 pairs were tested for antibody to Hong Kong (N2) neuraminidase by neuraminidase inhibition test (NI) and by SRD tests. Those with high titres in both tests resisted infection and those who were infected showed a rise in antibody detected both by NI and SRD tests. In general, SRDT was less sensitive than HI and NI in detecting antibody and antibody rises, but in some volunteers it did detect antibody rises which were not detected by conventional tests. Because of its simplicity and speed it appeared to be of use in evaluating such vaccines.

Antibodies, Viral↗
PubMed1973

The efficacy of live and inactivated vaccines of Hong Kong influenza virus in an industrial community. A report to the Medical Research Council Committee on influenza and other respiratory virus vaccines.

Intranasal vaccines of inactivated or living attentuated A2/Hong Kong influenza viruses were compared for clinical acceptability, serological effects and protective efficiency against natural epidemic influenza in a large industrial and clerical population.Neither vaccine resulted in any significant untoward side-effects. The serum haemagglutination-inhibiting (HI) antibody response within 1 month of vaccination was similar with both vaccines; approximately 50% of those with little or no pre-vaccination antibody developed 4-fold or greater rises in titre. The effect of the antigenic potency of the vaccines and the prior immunological experience of the population is discussed. Volunteers given live vaccine showed a 2.2-fold lower incidence of clinical influenza than those given killed vaccine in a natural epidemic 16 months after vaccination.

Antibody Formation↗
PubMed1973

In vitro antiviral activity and preliminary clinical trials of a new adamantane compound.

A compound, 1'-methyl spiro (adamantane-2,3'-pyrrolidine) maleate, chemically related to the antiviral drug amantadine, was tested for activity in vitro against a number of human respiratory viruses. By a variety of techniques, it was shown to be active against a wide range of human and animal influenza A viruses. The effect was, however, variable and ranged from high activity against two 1957 Asian strains to no observable activity against a 1971 strain. Like amantadine, the drug did not inhibit the growth of influenza B viruses. It was also inactive against a number of paramyxoviruses. Unlike amantadine, the drug did inhibit rhinoviruses, but to a lesser extent than myxoviruses. The coronavirus 229E was also sensitive to the action of the drug in vitro. Although an earlier trial in volunteers showed that, when given orally from 2 days before until 5 days after virus challenge, the drug was protective against infection with influenza A/Hong Kong/68 virus, a similar trial in volunteers challenged with rhinoviruses 2 and 9 revealed no useful activity against rhinoviruses in man.

Animals↗
PubMed1972

The role of serum haemagglutination-inhibiting antibody in protection against challenge infection with influenza A2 and B viruses.

The intranasal inoculation of volunteers with living partially attenuated strains of influenza A and B viruses offers a new opportunity to determine the protective effect of serum haemagglutin-inhibiting antibody against a strictly homologous virus, under conditions where the time and dosage of the infective challenge can be controlled, the scoring of proven infections can be more precise and higher rates of infection can be achieved than in most natural epidemics.In 1032 adult volunteers, whose serum HI antibody titre was determined immediately before virus challenge, there was a consistent inverse quantitative relationship between the HI titre and the likelihood of infection. The PD 50 (50% protective dose) of HI antibody was 1/18-1/36, but an unusual finding was that volunteers with no detectable pre-challenge antibody often seem to be less susceptible to infection than those with pre-challenge antibody in low titre.In one group of volunteers challenged with an influenza B strain there was no evidence that pre-challenge antibody titres against viral neuraminidase had any significant protective effect against challenge infection.

Administration, Intranasal↗
PubMed1972

Experimental infection of human volunteers with a swine influenzavirus antigenically related to the human A-Hong Kong-68 virus.

An influenzavirus of swine origin (swine/Taiwan/7310/70) antigenically closely related to the human A/Hong Kong/68 virus readily infected human volunteers. Those infected developed antihaemagglutinin and antineuraminidase antibodies to the human A/Hong Kong/68 virus as well as to the swine/Taiwan virus. The clinical reactions produced by the swine/Taiwan virus were, however, milder than those produced in volunteers infected with A/Hong Kong/68. In contrast, two other "classical" swine viruses (strains antigenically related to the prototype swine/Iowa/15/30 strain), immunologically distinct from the Hong Kong/68 virus, possessed low infectivity for man.

Animals↗
PubMed1971

Recombinant influenza-A viruses as live vaccines for man. Report to the Medical Research Council's Committee on Influenza and other Respiratory Virus Vaccines.

The infection of volunteers with five hybrid influenza-A viruses is described. Four of these were produced in Great Britain by recombining an Ao virus, non-infective for man, with a wild Hong Kong like strain. The fifth was the American recombinant, X-31, derived from similar parents and widely used in the manufacture of killed vaccines. All five viruses had the haemagglutinin and neuraminidase of A2/Hong Kong/68. Two of the viruses were not attenuated and induced symptoms of clinical influenza. The other three were appreciably attenuated and were infective and antigenic. It seems that recombination is a rapid and effective way of producing live vaccine viruses to specification. It is also the quickest known method of attenuation.

Antibodies, Viral↗