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Biomedical subjects

J R Kerr

Publications and source records attributed to J R Kerr.

At least 55 records · Page 3Linked to original sources

Follow-up study of clinical and immunological findings in patients presenting with acute parvovirus B19 infection.

This study was undertaken to examine the natural history of parvovirus B19 infection in persons without a known immune defect in terms of both clinical symptoms and immune responsiveness to the virus. Fifty-three patients with acute B19 infection (positive for serum anti-B19 IgM) were studied; symptoms at acute infection were rash and arthralgia (n = 26), rash (n = 7), arthralgia (n = 16), aplastic crisis (n = 3), and intrauterine fetal death (n = 1). Patients were followed for 26-85 months (mean 57 months) and reassessed for persistent symptoms, anti-B19 antibodies, and antibodies to the unique region of B19 VP1. There were 23 cases of arthralgia persisting for longer than 1 year after acute infection. One of these patients, a 48-year-old woman at follow-up, had had persistent arthralgia for 4 years following acute B19 infection, had rheumatoid factor at a titre of 1920 IU/ml detected at follow-up, and had been independently diagnosed as having rheumatoid arthritis at the time of follow-up. All 53 patients were positive for serum anti-B19 IgG compared to 45 of 53 age- and sex-matched control patients, a significant difference (two-tailed P value = 0.008). All test patients at follow-up and control patients were negative for serum anti-B19 IgM and antibodies to the unique region of B19 VP1. Serum from acute infection from 33 of 53 test patients was tested for antibodies to the unique region of VP1, and 16 of these were positive. The presence of this antibody did not correlate with subsequent duration of symptoms but did correlate with a short interval between symptom onset and blood sampling. The unique region of B19 VP1 is known to be crucial for a successful humoral response to the virus, and it seems that the antigenic role played by this region is important only during the acute phase of B19 infection.

Acute Disease↗

Parvovirus B19 infection.

Human parvovirus B19, discovered in 1974, is a single-stranded DNA virus which causes erythema infectiosum, arthralgia, aplastic crisis in patients with red cell defects, chronic anaemia in immunocompromised patients, and fetal hydrops. Seroprevalence in developed countries is 2-10% in children less than 5 years, 40-60% in adults more than 20 years, and 85% or more in those over 70 years. The virus may be transmitted by the respiratory route and by transfusion of infected blood and blood products. After an incubation period of six to eight days, viraemia occurs, during which reticulocyte numbers fall dramatically resulting in a temporary drop in haemoglobin of 1 g/dl in a normal person. Clearance of viraemia is dependent on development of specific antibody to the B19 structural proteins, VP1 and VP2. The red cell receptor for the virus is blood group P antigen. Diagnosis in immunocompetent persons depends on detection of specific IgM in serum. Diagnosis in immunocompromised persons depends on detection of B19 antigen or DNA in serum. There is no specific treatment for B19 infection; however, human normal immunoglobulin may be used as a source of specific antibody in chronically infected persons. A recombinant parvovirus B19 vaccine is under development.

Adult↗

Autoantibodies following parvovirus B19 infection.

This study was undertaken to assess the incidence and significance of autoantibody production following B19 infection, 53 patients with acute B19 infection (positive for serum anti-B19 IgM) were studied; symptoms were rash and arthralgia (n = 26), rash (n = 7), arthralgia (n = 16), aplastic crisis (n = 3), and intrauterine death (n = 1). These patients were followed for 26-85 months (mean 57 months) and re-assessed for persistent symptoms, serum anti-B19 antibodies, and serum autoantibodies. At follow-up, 14 test and two control patients had one or more serum autoantibodies (anti-nuclear antibody, anti-smooth muscle antibody, gastric parietal cell antibody, anti-reticulin antibody, anti-mitochondrial antibody, rheumatoid factor) at a titre of > or = 40 (P = 0.004). Seven test patients and no control patients had serum autoantibody at a titre > or = 160. Of these seven test patients, only one had persistent symptoms. At follow-up assessment, this woman was 48-year-old, had persistent arthralgia for 4 years following acute B19 infection, rheumatoid factor at a titre of 160 (1920 IU/ml), and had been independently diagnosed as having rheumatoid arthritis. In conclusion, results of the present study showed that low titre autoantibody production was common following symptomatic B19 infection, however, while interesting from a virological standpoint, this finding may be of little significance for future development of autoimmune disease.

Adolescent↗

The women's health agenda: evolution of hormone replacement therapy as treatment and prophylaxis for coronary artery disease.

The purpose of this paper is to develop an understanding of the research literature on the connection between hormone replacement therapy and development of coronary artery disease as it pertains to women. It is clear that research in this century regarding heart disease in general has been gender-biased or inappropriately gender-neutral. Research initially focused on how the developing knowledge of the protective effect of female hormones could be used to benefit men. It has only been in the last decade or so that gender-based research has been appreciated, acknowledged, facilitated, and finally accepted for its contributions to advancing knowledge and for benefiting women with coronary artery disease.

Bias↗

Inhibition of growth of fungi pathogenic to man by Stenotrophomonas maltophilia.

Ten strains of Stenotrophomonas maltophilia were tested by a cross-streaking method for in-vitro inhibition of 10 strains of fungi known to infect man; these were Candida krusei, C. keyfr, C. guillermondii, C. tropicalis, C. lusitaniae, C. parapsilosis, C. pseudotropicalis, C. albicans, C. glabrata and Aspergillus fumigatus. Significant inhibition of fungal growth was observed with all 10 strains of S. maltophilia, but not with Escherichia coli NCTC 10418, Staphylococcus aureus NCTC 6571 and Haemophilus influenzae NCTC 11931.

Aspergillus fumigatus↗

Design and production of a target-specific monoclonal antibody to parvovirus B19 capsid proteins.

Native parvovirus B19 was used as antigen to produce a mouse monoclonal antibody, R92F6, which reacted with B19 VP1 and VP2, neutralised the virus in bone marrow culture, and labelled infected cells in paraffin-embedded tissues from cases of B19-related fetal hydrops. The B19 epitope recognised by R92F6 (amino acids 328-344 from the amino terminal region of B19 VP2) appears to be highly conserved, since these tissue specimens were obtained over a 13 year period from widely spaced locations in the UK. This epitope was synthesised as a peptide (S7b) which was used as antigen to produce a mouse monoclonal antibody, 3H8, which specifically reacted with the B19 capsid proteins VP1 and VP2 in immunofluorescence and immunoblot assays. 3H8 was also capable of labelling formalin-fixed, paraffin-embedded, B19-infected fetal tissue and was shown to be of the same isotype as R92F6 (IgG1). Highly conserved epitopes derived from conserved amino acid sequences are valuable in the diagnosis of infectious disease. If these can be recognised and accurately synthesised, the production of specific mouse monoclonal antibodies may be possible for many human pathogens. Considering the vast amount of sequence data available in the literature, this approach seems to be both feasible and of wide potential.

Animals↗

Genetic diversity in the non-structural gene of parvovirus B19 detected by single-stranded conformational polymorphism assay (SSCP) and partial nucleotide sequencing.

A homologous region in the parvovirus B19 non-structural gene (B19 nt 1399-1682) was examined in 50 samples from patients with a wide variety of B19-related disease from various countries by PCR amplification, single-stranded conformational polymorphism (SSCP) assay and nucleotide sequencing. Five SSCP types were confirmed by nucleotide sequence analysis. Of a total of 6 mutations, all were silent. Types 3 and 4 accounted for 92% of strains. There was no correlation between genome type and either clinical illness or patient age. However, there was a correlation between SSCP type and country of origin. Type 3 strains predominated in Japan (18/26) and the UK (6/8), whereas type 4 predominated in the USA (9/12). Notably, type 3 strains also predominated among females (14/18), whereas there were approximately equal numbers of strain types 3 (7/17) and 4 (8/17) among males; an observation which remains unexplained. Within the Japanese group, although type 3 strains predominated overall, strains isolated from 1981 to 1987 consisted of types 1 (2/15), 2 (1/15), 3 (8/15), and 4 (4/15), whereas strains isolated from 1990 to 1994 consisted almost entirely of type 3 (10/11).

Adolescent↗

Investigation of a nosocomial outbreak of Pseudomonas aeruginosa pneumonia in an intensive care unit by random amplification of polymorphic DNA assay.

From July to September 1993 in the intensive care unit of the Royal Victoria Hospital there were 10 cases of pneumonia associated with sputum culture of Pseudomonas aeruginosa. The isolates had an identical biotype and pyocine typing profile. The same strain of P. aeruginosa was recovered from the sink plug-hole in two rooms, and the tap handles and ventilator tubing in a third room. All strains were retrospectively typed by the random amplification of polymorphic DNA (RAPD) method using a 26-mer oligonucleotide primer, and were identical in profile. Recommendations to medical and nursing staff included secretion isolation precautions, terminal disinfection after patient discharge, use of disposable vinyl gloves by hospital staff for all body substance contacts, thorough handwashing with 4% chlorhexidine gluconate before and after dealing with all patient contacts, and prompt, appropriate antibiotic treatment for P. aeruginosa pneumonia. RAPD is a simple and effective method to determine the relatedness of P. aeruginosa isolates, and typing results are available within a single working day; thus dramatically increasing its clinical relevance over existing molecular methods.

Bacterial Typing Techniques↗

A study of the role of parvovirus B19 in rheumatoid arthritis.

Serum and synovial tissue from 26 patients with rheumatoid arthritis (RA) (according to the diagnostic criteria of the American Rheumatism Association) and 26 patients with osteoarthritis (OA) were examined. Among the RA group, the female to male ratio was 4.2:1, and the age range was 44-82 yr with a mean of 64.0 yr; joints from which synovium was sampled were hip (n = 12), knee (n = 9), ankle (n = 3) and shoulder (n = 2). The duration of rheumatoid disease ranged from 6 to 24 yr with a mean of 13.9 yr. Among the OA group, the female to male ratio was 2.25:1, and the age range was 51-88 yr with a mean of 68.2 yr; joints from which synovium was sampled were hip (n = 18) and knee (n = 8). Twenty-one patients from the RA group and 20 patients from the OA group had evidence of previous parvovirus B19 infection (serum anti-B19 IgG), and all patients from both groups were serum anti-B19 IgM negative. Synovial sections from all 52 patients were stained with mouse monoclonal antibodies, 3H8 (to B19 capsid proteins) and alpha-P (to blood group P antigen). All tissue sections examined were found to be negative for both B19 capsid proteins and blood group P antigen. Using a nested polymerase chain reaction (PCR) assay, all patients were negative for serum B19 DNA. However, B19 DNA was demonstrated in the synovium of 10 of 26 RA patients and 9 of 26 OA patients; uncorrected chi 2 value = 0.08; degrees of freedom = 1; P = 0.77. All 19 patients testing positive for synovial B19 DNA had evidence of prior exposure to B19 infection (serum anti-B19 IgG). In conclusion, although there is published evidence of chronic rheumatoid-like arthropathy following acute parvovirus B19 infection, our findings do not support the involvement of B19 in the aetiopathogenesis of RA.

Adult↗

Satisfaction and cardiac lifestyle.

A descriptive, correlational approach was used to examine the relationship between success with a recommended cardiac lifestyle and satisfaction with a cardiac rehabilitation programme 1 year following completion. The Cardiac Lifestyle Questionnaire (CLQ) and the Programme Satisfaction Questionnaire (PSQ) evaluated success in eight lifestyle dimensions and four satisfaction areas. Seventy-two participants (85.7%) returned questionnaires. Successful lifestyle dimensions included exercise, tobacco, alcohol and weight; diet, stress and hypertension were unsuccessful. Two open-ended programme satisfaction questions revealed that 'caring' and 'individualized' approaches were most favoured by participants. These provide direction for high-quality care in cardiac rehabilitation programmes. Discriminant analysis did not yield a statistically significant separation of groups relative to cardiac lifestyle on the basis of programme satisfaction areas.

Adult↗