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Biomedical subjects

R J Shaw

Publications and source records attributed to R J Shaw.

At least 73 records · Page 4Linked to original sources
PubMed1997

Production of tumor necrosis factor and nitric oxide by macrophages infected with live and dead mycobacteria and their suppression by an interleukin-10-secreting recombinant.

We have analyzed mycobacterium-induced cytokine secretion in the J774A.1 macrophage-like cell line. Tumor necrosis factor alpha (TNF-alpha) was preferentially induced by live organisms, both slow and rapid growing. Expression of interleukin-10 by a recombinant strain of Mycobacterium smegmatis caused reduced production of TNF-alpha and nitric oxide during the early stages of infection.

Blotting, Western↗
PubMed1997

Differentiation of Mycobacterium tuberculosis isolates by spoligotyping and IS6110 restriction fragment length polymorphism.

Mycobacterium tuberculosis isolates from 167 patients attending three London hospitals were analyzed by two techniques for strain differentiation. A significant number of isolates that appeared identical with the recently developed spoligotyping system could be distinguished from each other by IS6110 restriction fragment length polymorphism analysis, with the latter technique demonstrating a generally higher level of discrimination. Spoligotyping, on the other hand, was particularly useful for analysis of isolates with low IS6110 copy numbers, and use of the two techniques in tandem provided an optimal approach to the identification of clusters with epidemiological evidence consistent with recent transmission. Spoligotyping can be applied directly to clinical samples by PCR and provides an important tool for the rapid detection of nosocomial transmission of individual strains.

Adolescent↗
PubMed1997

Cryptogenic fibrosing alveolitis: lack of association with Epstein-Barr virus infection.

BACKGROUND: Cryptogenic fibrosing alveolitis (CFA) is a well defined clinical entity of unknown aetiology. An association between CFA and the presence of protein indicating Epstein-Barr virus (EBV) replication within epithelial cells of the respiratory tract has recently been suggested, leading to speculation for a role for EBV in the pathogenesis of CFA. METHODS: Lung tissue was obtained from patients in three groups: those with cryptogenic fibrosing alveolitis, either lone or associated with systemic sclerosis; patients with other pulmonary disorders; and patients with normal lung. Paraffin blocks were stained using three antibodies raised against well defined EBV antigens. In addition, EBER-1 and EBER-2 anti-sense nucleotide probes were used in an attempt to identify EBV RNA. DNA was also extracted from the tissue sections and evaluated for evidence of EBV DNA using the polymerase chain reaction. RESULTS: Immunohistochemistry showed inconsistent focal positive staining with anti-EBV antibodies in all three groups, but there was no evidence of EBV RNA using in situ hybridisation. None of the samples from patients with pulmonary fibrotic disorders was found to contain EBV DNA following gene amplification. CONCLUSION: Contrary to an earlier report, these results do not support the hypothesis that EBV has a role in the pathogenesis of CFA.

DNA, Viral↗
PubMed1997

Pulmonary artery occlusion by tuberculous mediastinal lymphadenopathy.

Two cases of tuberculous mediastinal lymphadenopathy are presented in which the clinical features mimicked those of pulmonary embolism, causing striking abnormalities on radionuclide scintigraphy. It is concluded that tuberculous mediastinal lymphadenopathy should be included in the differential diagnosis of reduced lung perfusion due to proximal pulmonary artery occlusion.

Adult↗
PubMed1997

Rapid detection of multidrug-resistant tuberculosis.

Transmission of multidrug-resistant strains of Mycobacterium tuberculosis (MDR-TB) presents a serious problem for infection control in hospitals, particularly in the context of co-infection with the human immunodeficiency virus (HIV). We report on the use of molecular genetic tools to allow rapid assessment of samples from patients potentially infected with MDR-TB. Sputum and bronchoalveolar lavage samples were obtained from two HIV-positive patients with suspected tuberculosis, who had previous contact with a known MDR-TB index case. Polymerase chain reaction (PCR) was used directly on clinical samples to amplify genetic loci associated with rifampicin resistance (rpoB), and strain-specific polymorphisms (the direct repeat (DR) region). Drug resistance was determined using a commercially available kit for detection of point mutations in the rpoB gene (Inno-Lipa RifTB; Innogenetics, Belgium), and confirmed by nucleotide sequencing. Strain variation was determined using the spoligotyping method, based on the presence or absence of variable linker sequences within the DR region. In one patient, infection with a MDR strain identical to that of a known index case was demonstrated. A second patient, although positive for M. tuberculosis, was found to be infected with a rifampicin-sensitive strain. Results were obtained within 48 h, allowing appropriate treatment to be initiated and infection control measures to be implemented. PCR-based tests for strain-typing and for identification of rifampicin resistance provide important tools for identifying patients with MDR-TB and for rapid monitoring of potential nosocomial spread of MDR-TB. Prompt confirmation or exclusion of possible transmission allows early clinical intervention to prevent future outbreaks of multidrug-resistant M. tuberculosis.

Antibiotics, Antitubercular↗
PubMed1996

Production and characterisation of monoclonal antibodies recognising ovine IgE.

Two monoclonal antibodies (mAbs), XB6 and YD3, which recognise ovine immunoglobulin E (IgE) were produced. Mast cells isolated from ovine intestinal mucosa were used as a source of IgE to immunize mice. Culture supernatants of hybridomas were screened by immunoassays on small-intestine tissue sections, isolated mucosal cells, and dot blots of lysed mast cell homogenate. Two mAbs were chosen for their specific binding to mast cells. Antigen bound by these mAbs was purified by immunoaffinity chromatography using XB6 mAb, and this produced two bands consistent with IgE heavy chain (86,000 Daltons) and immunoglobulin light chain (28,000 Daltons) when run under reducing conditions on SDS-PAGE gels. Purified IgE was shown on dot blots to react weakly with mAb to chimeric ovine IgE and strongly to polyclonal anti-sheep antibodies. The two mAbs induced an immediate hypersensitivity-like reaction when injected into the skin of sheep. The mAbs bound to mast cells and other mononuclear cells, presumably IgE-secreting B-cells in mesenteric lymph node sections. These mAbs proved useful for detecting IgE-bearing cells in various ovine tissues, for purifying mast cells from cell isolates by panning and immunomagnetic bead separation, for purifying serum IgE using immunoaffinity chromatography and for detecting IgE in an ELISA. Competitive binding assays showed that the two mAbs bind to different epitopes on IgE. These mAbs will be useful in research applications and in diagnostic assays.

Anaphylaxis↗
PubMed1996

Thunderstorm associated asthma: a detailed analysis of environmental factors.

OBJECTIVES: To seek associations between meteorological factors, concentrations of air pollutants or pollen, and an asthma epidemic which occurred in London on 24 and 25 June 1994 after a thunderstorm. DESIGN: Retrospective study of patients' accident and emergency department records, with bivariate and multivariate analysis of environmental factors and data collection for the two months surrounding the epidemic. SETTING: The accident and emergency department of St Mary's Hospital in west central London. SUBJECTS: 148 patients presenting with asthma between 1 June and 31 July 1994, of whom 40 presented in the 24 hours after the storm. RESULTS: The asthma epidemic was significantly associated with a drop in air temperature six hours previously and a high grass pollen concentration nine hours previously. Non-epidemic asthma was significantly associated with lightning strikes, increase in humidity or sulphur dioxide concentration, a drop in temperature or high rainfall the previous day, and a decrease in maximum air pressure or changes in grass pollen counts over the previous two days. CONCLUSIONS: New episodes of asthma during the epidemic on 24 and 25 June 1994 were associated with a fall in air temperature and a rise in grass pollen concentration. Non-epidemic asthma was significantly associated with a greater number of environmental changes. This may indicate that the patients with thunderstorm associated asthma were a separate population, sensitive to different environmental stimuli.

Air Pollutants↗
PubMed1996

Temperament as a correlate of adolescent defense mechanisms.

The Revised Dimensions of Temperament Survey, which assesses nine dimensions of temperament, and the Defense Style Questionnaire, used to assess defense mechanisms, were completed by 107 female adolescents. Temperament was found to be strongly correlated with defense style, particularly with immature defenses (p = 0.0001). The findings support the hypothesis that the biological dimension of temperament is correlated with specific defense mechanisms.

Adolescent↗
PubMed1996

The immune response of sheep surgically modified with intestinal loops to challenge with Trichostrongylus colubriformis.

Aspects of the local immune response to nematode challenge were investigated in vivo in isolated loops of the upper small intestine of mature sheep that were immunised by repeated infections with Trichostrongylus colubriformis infective larvae (L3). Groups of 3 sheep were challenged either through the loop (Group 1) or orally (Group 2) with T. colubriformis L3, the third group served as unchallenged controls (Group 3). Nematode specific antibody levels, mast cell proteinase levels (SMCP) and larval migration inhibition (LMI) activity were determined in loop secretions for 4 weeks after challenge. The intestinal loops remained functional throughout the experiment. Groups 1 and 2 were re-challenged 2 weeks after the first challenge, and all 3 Groups were slaughtered 2 weeks later. Histopathological examination showed elevated numbers of globule leukocytes (GL) in both the nematode-challenged loop and unchallenged small intestine of Group 1 and small intestine of Group 2 indicating that nematode infections induce the local appearance of large numbers of GL. Oral, but not loop challenge caused increased antibody levels in loop secretions when compared to unchallenged controls. Only loop-challenged sheep showed a peak in loop fluid SMCP levels 10-13 days after the first challenge which coincided with a peak in numbers of mucosal GL. The isolated loops of all 3 groups showed highly elevated numbers of eosinophils when compared to the intact small intestine. Loop fluid of all 3 groups showed a high level of LMI activity reflecting the high level of nematode-resistance induced by the immunisation procedures. Sheep in Groups 1 and 2 were both able to expel challenge infections, and when compared to Group 3, showed higher blastogenic activity of unstimulated cells derived from a mesenteric lymph node in the region of the challenged part of the intestine. The present experiment showed that surgically constructed intestinal loops provided a model system by which the substantial changes associated with the local intestinal immune response to challenge with T. colubriformis could be investigated.

Animals↗
PubMed1996

Cross-reacting antibodies to Sarcoptes suis, Chorioptes bovis and Notoedres cati and anti-P. ovis IgE in sera from sheep infested naturally with Psoroptes ovis.

For the development of immunodiagnostic tests to detect mange mite infections in man and animals, it is necessary to know about antigen structure and cross-reactivity between different mite species and other arthropods in contact with the host. Sera from sheep infected with Psoroptes ovis (sheep anti-P. ovis sera) showed positive reactions in dot blots to P. ovis antigen and cross-reactivity to crude antigen extracts from Sarcoptes suis, Notoedres cati and Chorioptes bovis. Using sheep Specific Pathogen Free (SPF) sera in dot blots, weak reactions were seen to all but the Ch. bovis antigen. In SDS PAGE-separated P. ovis antigens at least 35 different proteins could be distinguished. In western blots, at least 24 out of these 35 were recognized as antigens by sheep anti-P. ovis immunoglobulins. At least 13 were recognized by sheep anti-P. ovis IgE. One of these, at 19 kDa, was recognized only with sheep anti-P. ovis IgE, the other 12 also with anti-P. ovis immunoglobulins. Cross-reactive antigens were recognized by sheep anti-P. ovis immunoglobulins in SDS PAGE-separated, and nitrocellulose transferred mite extracts in western blots as follows: 13 antigens in S. suis extracts, 9 in N. cati and 8 in Ch. bovis. Sheep SPF sera recognized an antigen at 67 kDa in each of these 4 mite species. Rabbit anti-sheep immunoglobulins in the P. ovis antigen control bound to a protein at 28 kDa which may be sheep IgG light chain taken up by P. ovis feeding on sheep. Despite the antigenic similarities between mange mites, sufficient differences were apparent to make immunodiagnostic tests for mange feasible.

Animals↗
PubMed1996

Sequential cellular and humoral responses in the abomasal mucosa and blood of Romney sheep dosed with Trichostrongylus axei.

Abomasal cannulae were surgically placed in 7 2-year-old New Zealand Romney sheep which had been maintained parasite-free from birth. Four of these sheep were randomly selected and dosed orally with 10,000 infective Trichostrongylus axei larvae per week for 8 weeks, while the remaining 3 sheep served as uninfected controls. Abomasal biopsy, blood and faecal samples were obtained from all sheep at regular intervals from 5 days before and until 58 days after the first infection. The sheep were then killed, worm burdens assessed and abomasal and small intestinal samples collected Faecal egg counts of all 4 dosed sheep were low and only one (No. 701) had a substantial worm burden (8400) post mortem. Overall, levels of mucosal mast cells/globule leukocytes, eosinophils, T19+ cells and larval migration inhibitory activity increased significantly in the abomasal mucosa of the dosed sheep compared to the controls. The CD4+:CD8+ cell ratio in the abomasal mucosa of the dosed sheep also increased compared to that of the controls (P = 0.06). In blood, T. axei-specific antibody (total and IgG1) and eosinophil numbers increased significantly in the dosed sheep. Mucosal cells staining for IgE (IgE+), and blood and mucosal eosinophils showed the earliest substantive increases in number followed by increases in specific serum antibody levels, numbers of mucosal cells fluorescing under UV light (UVf) and T19+ cells. The difference in the IgE+ and UVf cell responses indicated that expansion of globule leukocyte numbers lagged behind that of mucosal mast cells. The results supported the concept of CD4+ T cell help in the abomasal mucosa and defined the sequential expression of components of the immunological responses potentially mediating resistance to T. axei. In sheep No. 701, persistence of adult worms was associated with lower mucosal IgE+ cell and eosinophil responses compared with the other dosed sheep.

Abomasum↗
PubMed1996

Increase in the concentration of transforming growth factor beta-1 in bronchoalveolar lavage fluid before development of chronic lung disease of prematurity.

OBJECTIVE: Pulmonary fibrosis is a prominent feature of chronic lung disease of prematurity (CLD). We sought to determine the influence of the potent profibrotic cytokine transforming growth factor beta-1 (TGF-Beta 1) on the development of CLD. METHODS: We determined the concentration of active and total TGF-Beta 1 in bronchoalveolar lavage fluid obtained from 18 infants who subsequently had CLD (mean gestation, 25.7 weeks; birth weight, 816 gm) 15 (29.8 weeks, 1493 gm) who recovered from the respiratory distress syndrome, and 7 (35.1 weeks, 2441 gm) control infants. RESULTS: The concentration of both active and total TGF-Beta 1 was increased in the infants with CLD when compared with the respiratory distress syndrome and control groups. The increase in active and total TGF-Beta 1 was greatest on day 4 of age, when infants who eventually had CLD were compared with those who did not progress to CLD (active TGF-Beta 1, 39.5 vs 4.6 ng/ml; total TGF-Beta 1, 43.8 vs 13.8 ng/ml). In addition, immunocytochemistry studies localized pan-TGF-Beta to alveolar macrophages obtained by bronchoalveolar lavage. CONCLUSIONS: These observations indicate that TGF-Beta 1 may contribute to the fibrotic response that is observed in the lungs of infants who have CLD.

Bronchoalveolar Lavage Fluid↗
PubMed1996

A prospective clinical evaluation of the longevity of resorbable sutures in oral mucosa.

A prospective, randomised and controlled clinical investigation was undertaken to evaluate the longevity of resorbable sutures in the oral environment. The sutures investigated were gut, polyglycolic acid and polyglactin 910, were of standard gauge and needle type, and were placed using a standard technique by trained clinicians. The sutures were monitored following apical surgery in 55 patients (110 sutures) and the median survival values were: gut - 4 days, polyglycolic acid - 15 days, polyglactin 910 - 28 days. These differences were highly statistically significant. A postal survey of 30 randomly selected oral and maxillofacial surgeons reveal most prefer to use resorbable sutures, with softgut the most popular choice. Most would like an ideal resorbable suture to last 5 to 14 days and in this respect none of the materials tested appears satisfactory.

Absorption↗