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Biomedical subjects

R Postlethwaite

Publications and source records attributed to R Postlethwaite.

At least 19 recordsLinked to original sources
PubMed1989

Epidemiology of molluscum contagiosum using genetic analysis of the viral DNA.

The molecular epidemiology of molluscum contagiosum virus (MCV) infections was investigated by restriction endonuclease analysis of the genomes of 222 separate isolates collected from 147 patients living in Germany (33 patients), Hong Kong (6 patients), and Scotland (108 patients). MCV type 1 (MCV-1) caused 96.6% of the infections, and MCV type 2 (MCV-2) caused 3.4%. However, isolates from four of the 142 MCV-1-infected patients and two of the five MCV-2-infected patients showed minor differences in their DNA restriction patterns because of the loss of a single or very few recognition sites for the enzymes used. No genome variations were detected amongst isolates collected from different sites or on several occasions from individual patients or from closely related patients. Southern blot hybridization revealed a high level of relatedness between MCV-1 and 2. No differences were seen in the appearance or anatomical localization of lesions caused by either virus type. In particular, there was no preferred genital localization for MCV-2 infections.

Adolescent↗
PubMed1988

Virulence of Listeria spp.: course of infection in resistant and susceptible mice.

The virulence of representative strains of the five species of Listeria monocytogenes sensu lato was compared in C57BL/6 and BALB/c mice in terms of LD50 values and of bacterial growth kinetics and histological changes in mouse livers. L. monocytogenes sensu stricto and L. ivanovii showed relatively low LD50 values and much bacterial growth for 2-3 days before viable counts declined. Histological changes in L. ivanovii infection resembled those caused by L. monocytogenes, with early development of neutrophil-rich micro-abscesses and hepatocyte necrosis followed by macrophage infiltration and formation of granulomas. By contrast, L. innocua, L. welshimeri and L. seeligeri were almost entirely avirulent as shown by high LD50 values, early elimination of viable bacteria and no evidence of growth. Histological changes consisted only of slight, transient infiltration of the liver with neutrophils. Both groups of bacteria were seen infrequently in Kupffer cells early in infection, but only the highly virulent species appeared to replicate. LD50 values for L. monocytogenes and L. ivanovii were (10-20)-fold greater, and for the less virulent bacteria at least two-fold greater, in C57BL/6 than in BALB/c mice. This difference in host susceptibility was not reflected in detectable histological differences between the two mouse strains.

Animals↗
PubMed1986

Stress inoculation for acute pain: a clinical trial.

The study attempted a clinical evaluation of the efficacy of stress inoculation training for postoperative pain control using patients undergoing coronary artery graft surgery. A treatment group receiving stress inoculation training was compared to attention-education and no-treatment control groups. No differences were found between the groups on two pain rating measures, analgesic intake, or measures of state anxiety and depression. The ineffectiveness of stress inoculation in this study may be due to the difference between experimental and clinical pain, the multiple demands of the preoperative period, possible memory difficulties which some patients may have experienced, or the possibility that the procedure is not sufficiently potent for the intensity of this type of pain.

Acute Disease↗
PubMed1986

Carriage of Listeria monocytogenes and related species in pregnant and non-pregnant women in Aberdeen, Scotland.

The faecal, cervico-vaginal and oropharyngeal carriage of Listeria species in 54 healthy pregnant women and 60 healthy non-pregnant women was investigated. Samples were cold-enriched at 4 degrees C and subcultured on selective media containing acriflavin, nalidixic acid and potassium thiocyanate. Listeria monocytogenes was isolated from the faeces of one pregnant woman (2%) and two non-pregnant women (3.4%). Listeria innocua was isolated from the faeces of one pregnant woman (2%) and one non-pregnant woman (1.7%). Listeria seeligeri was isolated from the faeces of one non-pregnant woman (1.7%). Listeria species were not isolated from cervico-vaginal or oropharyngeal samples. The results indicate that pregnancy does not affect the naturally low carriage rate of Listeria species.

Adolescent↗
PubMed1986

Pseudallescheriasis in northern Britain.

Five cases of Pseudallescheria boydii infection are reported from the northern part of the United Kingdom. None of the patients had travelled abroad. Three cases of otitis in which P. boydii was associated with bacterial infections were diagnosed within a 6-month period. A lady who had diabetes mellitus presented with a pulmonary fungus ball in a pre-existent cavity caused by a previous bacterial infection. After minor trauma at the site of an old skin graft, a farmer's wife developed an ulcer on the dorsum of the right ankle. Precipitating antibodies were demonstrated except in two of the cases of ear infection. The management of the individual cases is discussed.

Aged↗
PubMed1986

Parvovirus infection in a family with wheeze in an adult.

In a family outbreak of human parvovirus infection, a 59-year-old doctor had a prodromal illness with wheeze. This was followed by a distinct acute episode with itch and arthropathy and a two-month phase characterized by intermittent cough and wheeze.

Antibodies, Viral↗
PubMed1984

Disseminated histoplasmosis.

A case of chronic disseminated histoplasmosis, presenting 16 years after returning to Scotland from West Bengal, is reported. The difficulties and pitfalls in diagnosis and management are emphasised.

Aged↗
PubMed1978

Infection of mouse liver by human adenovirus type 5.

CBA mice, inoculated intravenously with large doses of adenovirus type 5, showed raised levels of serum aspartate aminotransferase (SAAT; EC 2.6.I.I) and died within a few days from histologically demonstrable hepatic necrosis. After inoculation of I LD50, virus was rapidly taken up by the tissues where infectivity then declined greatly. Organ titres then increased about 100-fold by 48 h p.i. but, in the liver, which showed intranuclear inclusion bodies, and by electron microscopy, scattered intranuclear and intracytoplasmic adenovirions, the increase was 10000- to 100000-fold. P antigen was detected by single radial diffusion in liver extracts, and by immunofluorescence in 80% of liver cells at 36 h p.i. Hexon, penton base and fibre antigens appeared later and in fewer cells. The maximum amount of hexon, of demonstrable type 5 specificity, was shown by radioimmunoassay to be equivalent to up to 5 x 1011 whole adenovirions/g liver. It is concluded that human adenovirus type 5 undergoes an abortive but lytic infection in most liver cells but that replication may proceed to completion in a few.

Adenoviridae Infections↗
PubMed1976

Molluscum contagiosum -- a defective poxvirus?

Purified preparations of molluscum contagiosum virus contain a DNA-dependent RNA polymerase (EC 2.7.7.6) with similar but not identical properties to those of the enzyme found in vaccinia virions. The ultraviolet inactivation kinetics of the RNA polymerase from both viruses were similar, displaying fast and slow components. Ultraviolet irradiation destroyed the interfering capacities of molluscum and inactivated vaccinia virions, and the interferon-inducing capacity of molluscum virus slowly and with first-order kinetics. Inactivation studies of the interferon-inducing capacity of vaccinia virus were complicated by cytotoxic effects. Electron microscopical studies showed all stages of virus growth in vaccinia-infected mouse embryo cells; molluscum virus appeared to be degraded in lysosome-like bodies. In preliminary studies, marked changes in cytoplasmic RNA synthesis and in patterns of polypeptide synthesis were found in vaccinia-infected but not in molluscum-infected mouse embryo cells.

Adsorption↗
PubMed1974

Antibody responses to antigenic determinants of influenza virus hemagglutinin. I. Thymus dependence of antibody formation and thymus independence of immunological memory.

Using immunodiffusion methods it has been shown that purified hemagglutinin (HA) extracted from two related strains of influenza A viruses (A/PR8/34 and A/FM1/47) have two distinct antigenic determinants, or groups of determinants. One determinant is cross-reactive while the other is strain-specific. Antisera raised in normal mice against HA were shown to contain two populations of antibody molecules, each directed against one of the determinants. Immunization of thymus-deprived (TXBM) mice showed a strong thymus dependence of antibody formation to HA. However, the thymus dependence of antibody formation against the cross-reactive determinant could be overcome by repeated inoculations of HA in TXBM mice, indicating a different handling of two portions of the same molecule by the immunological system. Strong, secondary-type responses to the strain-specific determinant were observed in primed thymus-deprived mice after reconstitution with virgin thymus cells, showing that specific immunological memory was elicited by this determinant despite the absence of detectable antibody secretion. These findings are interpreted as examples of immunological recognition and memory mediated by B lymphocytes and discussed in terms of mechanisms of T and B lymphocyte co-operation. It is suggested that the helper effect of T lymphocytes is exerted at a late stage in the differentiation of specific populations of B cells into antibody-secreting cells.

Animals↗